Salmonella typhimurium

J Antimicrob Chemother, 1986 Oct, 18 Suppl C, 175 - 7
R plasmids in Salmonella typhimurium in the United Kingdom; Threlfall EJ et al.; In the United Kingdom, R plasmids are common in bovine-associated phage types of Salmonella typhimurium and in particular in strains of phage type 204c (DT204c); all strains of this type carry at least three R plasmids . Gentamicin resistance appeared in DT204c in 1983 and plasmids conferring resistance to gentamicin also code for resistance to apramycin . Three types of apramycin-gentamicin resistance plasmid have been identified.

Appl Environ Microbiol, 1986 Oct, 52(4), 718 - 22
Mutagenicity of the Alternaria metabolites altertoxins I, II, and III; Stack ME et al.; The Ames Salmonella typhimurium assay was used to demonstrate that an extract of the mold Alternaria alternata was mutagenic . The mutagenic extract was fractionated, and the Ames test was used to determine which fractions were mutagenic . Subsequently, altertoxins I and II and a new compound referred to as altertoxin III were isolated by liquid chromatography and shown to be hydroxyperylenequinone compounds by mass spectrometry and infrared, ultraviolet, and proton magnetic resonance spectroscopy . Altertoxins I, II, and III were mutagenic to S . typhimurium TA98, TA100, and TA1537 with and without metabolic activation.

Proc Natl Acad Sci U S A, 1986 Oct, 83(19), 7157 - 61
Restoration of flagellar clockwise rotation in bacterial envelopes by insertion of the chemotaxis protein CheY; Ravid S et al.; When cells of the bacterium Salmonella typhimurium are incubated with penicillin and lysed in a dilute buffer, flagellated cytoplasm-free envelopes are formed . When the envelopes are tethered to glass by their flagella and then energized, some of them spin . The direction of rotation of wild-type envelopes is exclusively counterclockwise (CCW) . We perturbed this system by including in the lysis medium (and hence in the envelopes) the chemotaxis protein CheY . As a result, some of the envelopes rotated exclusively clockwise (CW) . The fraction of envelopes that did so increased with the concentration of CheY; at a concentration of 48 microM (pH 8), all functional envelopes spun CW . The fraction also increased with the pH of the lysis medium in the range of 6.6-8.4 . The results were the same in the presence or absence of intracellular Ca2+ . Reconstituted envelopes failed to respond to chemotactic stimuli . None of them changed the direction of their rotation . However, when the intracellular pH was lowered to 6.6 or below, envelopes that spun CW stopped rotating, while envelopes that spun CCW continued to rotate . This phenomenon was reversible . We conclude that CheY per se, without any additional free cytoplasmic mediators, interacts with a switch at the base of the flagellum to cause CW rotation.

Mutat Res, 1986 Oct, 175(2), 51 - 9
Aspects of chloroquine mutagenicity; Obaseiki-Ebor EE et al.; Using the Ames plate reversion and fluctuation tests, the mutagenic activity of chloroquine was tested in the new tester strains of Salmonella typhimurium, TA97, TA102, and Escherichia coli strains WP2, WP2hcr, WP6 and WP67 . The E . coli transconjugants obtained from the mating transfer of R-plasmid(s) in strains TA97 and TA102 respectively to E . coli WP2, i.e . EE97 and EE102, were also tested . Chloroquine reverted strain TA97 from histidine dependence to independence and also reverted E . coli strains EE97 and EE102 from tryptophan dependence to independence . The E . coli strains WP2, WP2hcr; WP6 and WP67 and S . typhimurium TA102 were not affected . S . typhimurium TA97 could be reverted with 250 ng/ml of chloroquine (therapeutic blood level of chloroquine is 300 ng/ml) . Reversion generally occurred optimally at the relatively lower concentrations of chloroquine i.e . 25, 50 micrograms/ml than at higher concentrations . From the properties of the reverted tester strains, the results indicated that chloroquine per se mediated frameshift reversion.

Mutat Res, 1986 Oct, 172(1), 37 - 45
Xanthine oxidase-mediated mutagenicity of the bladder carcinogen 4-nitrobiphenyl; Swaminathan S et al.; Xanthine oxidase catalyzed mutagenicity of 4-nitrobiphenyl (NBP), a dog-bladder carcinogen, was tested in Ames assay using Salmonella typhimurium TA98 strains . NBP was active as a mutagen in the parent strain TA98 which is proficient in nitroreductase, while it was inactive in the strain TA98NR which is deficient in nitroreductase . However, preincubation of NBP at 37 degrees C with NADH and commercial preparations of xanthine oxidase for 30 min resulted in a dose-dependent increase in the mutagenic activity in TA98NR . Allopurinol blocked the xanthine oxidase catalyzed mutagenicity of NBP in TA98NR and the extent of inhibition was dependent upon the concentration of the inhibitor . Rat-liver and dog-bladder cytosol preparations also enhanced the mutagenic activity of NBP in TA98NR in a dose-dependent manner . In addition, the cytosol-mediated activity was also inhibited by allopurinol, implying that the cytosolic enzyme activity might be due to xanthine oxidase . In vitro enzymatic reduction of NBP using bacterial cell lysates of TA98 and TA98NR revealed the major product of reduction to be 4-aminobiphenyl . The transient intermediates of reduction were not detected during the in vitro incubation . The reduction intermediate N-hydroxylaminobiphenyl showed direct and equal mutagenic activity in both TA98 and TA98NR, in contrast to NBP . These results suggest that N-hydroxylaminobiphenyl is generated during the preincubation of NBP with xanthine oxidase or cytosolic preparations and the former might account for the mutagenicity of NBP . Furthermore, the occurrence of such enzyme(s) in the target tissue for NBP carcinogenesis, support the hypothesis that metabolic activation of the bladder carcinogen NBP could occur within the target organ by virtue of its intrinsic metabolic potential.

Mutat Res, 1986 Oct, 172(1), 29 - 36
Selective mutagenic activity of 2-bromo-propanamides on Salmonella typhimurium . A structure-activity study; Dolzani L et al.; Nineteen 2-halogeno-acetamides, -propanamides, and -iso-butyramides and four related epoxyamides were tested as mutagens for Salmonella typhimurium TA100 . Mutagenic activity was observed in strictly selected 2-halogenoamides and in all epoxyamides . The effectiveness of 2-halogenoamides depends upon: the character of the carbon carrying the halogen (1 degree, 2 degrees, 3 degrees); the nature of the halogen (Br, Cl); the substitution at nitrogen . Some considerations concerning the selectivity observed are presented.

Mutat Res, 1986 Oct, 172(1), 19 - 27
Mutagenicity of the photochemical reaction products of pyrene with nitrogen dioxide; Hisamatsu Y et al.; The mutagenicity of the photochemical reaction products of pyrene with nitrogen dioxide (NO2) and the mutagens in them were investigated for the interpretation of their biological significance as genetoxic hazards of polycyclic aromatic hydrocarbons (PAHs) in airborne particles . Samples extracted from the photochemical reaction products of pyrene with NO2 diluted with air using a high-pressure mercury lamp were mutagenic for Salmonella typhimurium strains TA97 and TA98 in the absence of S9 mix, with a trend to detoxification in the presence of the metabolic system . The mutagens in the crude samples extracted from their products, which were fractionated by normal-phase high-performance liquid chromatography (HPLC) on a column of Nucleosil 100-30 with n-hexane-benzene as an eluting solution, were analyzed by HPLC, mass spectrometry and Fourier transform infrared (FT-IR) spectrometry . Based on these results, it was recognized that 1-nitropyrene (1-NP), 1,3-dinitropyrene (1,3-DNP), 1,6-dinitropyrene (1,6-DNP) and 1,8-dinitropyrene (1,8-DNP) was formed by the photochemical reaction of pyrene with NO2 . The yield of DNPs peaked at 2-3 h irradiation.

J Bacteriol, 1986 Oct, 168(1), 437 - 9
Cloning and characterization of the gene encoding 3-deoxy-D-manno-octulosonate 8-phosphate synthetase from Escherichia coli; Woisetschlager M et al.; The cloning of the gene for Escherichia coli PL-2 2-keto-3-deoxy-D-manno-octonate 8-phosphate synthetase is reported . Positive transformants showed an increase of approximately three-fold in specific activity of the enzyme both in E . coli and in Salmonella typhimurium as host cells . A subclone containing a 1.5-kilobase PvuII fragment overproduced active enzyme . Minicell experiments that allow the detection of plasmid encoded proteins revealed an insert-coded single protein band of 34 kilodaltons.

J Bacteriol, 1986 Oct, 168(1), 420 - 4
Global control in Salmonella typhimurium: two-dimensional electrophoretic analysis of starvation-, anaerobiosis-, and heat shock-inducible proteins; Spector MP et al.; The response of Salmonella typhimurium to various forms of environmental stress was examined by using O'Farrell two-dimensional gel electrophoresis . Polypeptides (a total of 110) which quantitatively increased during various starvations, anaerobiosis, or heat shock were identified and cataloged in reference to a standard polypeptide map . Although significant overlap was noted during comparison of proteins induced by different starvations, only a few proteins produced during heat shock or anaerobiosis were also identified as starvation inducible.

J Bacteriol, 1986 Oct, 168(1), 398 - 404
Characterization and physiological roles of membrane-bound hydrogenase isoenzymes from Salmonella typhimurium; Sawers RG et al.; We found that Salmonella typhimurium strain LT2 (Z) possessed two immunologically distinct, membrane-bound hydrogenase isoenzymes, which were similar in electrophoretic mobilities and apoprotein contents to hydrogenase isoenzymes 1 and 2 of Escherichia coli . The S . typhimurium enzymes cross-reacted with antibodies raised to the respective hydrogenase isoenzymes of E . coli . As for E . coli, an additional membrane-bound hydrogenase activity (termed hydrogenase 3), which did not cross-react with antibodies raised against either hydrogenase 1 or 2, was also present in detergent-dispersed membrane preparations . The physiological role of each of the three isoenzymes in E . coli has remained unclear owing to the lack of mutants specifically defective for individual isoenzymes . However, analysis of two additional wild-type isolates of S . typhimurium revealed specific defects in their hydrogenase isoenzyme contents . S . typhimurium LT2 (A) lacked isoenzyme 2 but possessed normal levels of hydrogenases 1 and 3 . S . typhimurium LT7 lacked both isoenzymes 1 and 2 but retained normal hydrogenase 3 activity . Characterization of hydrogen metabolism by these hydrogenase-defective isolates allowed us to identify the physiological role of each of the three isoenzymes . Hydrogenase 3 activity correlated closely with formate hydrogenlyase-dependent hydrogen evolution, whereas isoenzyme 2 catalyzed hydrogen uptake (oxidation) during anaerobic, respiration-dependent growth . Isoenzyme 1 also functioned as an uptake hydrogenase but only during fermentative growth . We postulate that this enzyme functions in a hydrogen-recycling reaction which operates during fermentative growth.

J Bacteriol, 1986 Oct, 168(1), 389 - 97
Two genetically distinct pathways for transcriptional regulation of anaerobic gene expression in Salmonella typhimurium; Jamieson DJ et al.; Expression of the tripeptide permease gene tppB is anaerobically induced . This induction is independent of the fnr (oxrA) gene product, which is known to be required for the anaerobic induction of several respiratory enzymes . We isolated, characterized, and mapped mutations in two genes, oxrC and tppR, which prevent the anaerobic induction of tppB expression . Mutations in oxrC were highly pleiotropic, preventing the anaerobic expression of the formate dehydrogenase component of formate hydrogen lyase (fhl), a tripeptidase (pepT), and two of the three known hydrogenase isoenzymes (hydrogenases 1 and 3) . On the other hand, expression of nitrate reductase, fumarate reductase, and a number of other fnr (oxrA)-dependent enzymes was not affected by mutations in oxrC . Thus, there appeared to be at least two distinct classes of anaerobically induced genes, those which required fnr for their expression and those which required oxrC . It seems that fnr-dependent enzymes perform primarily respiratory functions, whereas oxrC-dependent enzymes served fermentative or biosynthetic roles . We found the primary defect of oxrC mutants to be a deficiency in phosphoglucose isomerase activity, implying that a product of glycolysis functions as an anaerobic regulatory signal . Mutations in tppR were specific for tppB and did not affect expression of other oxrC-dependent genes . However, tppR did exhibit phenotypes other than the regulation of tppB . Both oxrC and tppR mutants were hypersensitive to the toxic NAD analog 6-aminonicotinic acid . This suggests that oxrC and tppR may play a role in the regulation of NAD biosynthesis or, alternatively, that NAD or a related nucleotide serves as the anaerobic signal for oxrC-dependent enzymes.

J Bacteriol, 1986 Oct, 168(1), 328 - 33
Control of lipopolysaccharide biosynthesis and release by Escherichia coli and Salmonella typhimurium; Ishiguro EE et al.; The influence of the relA gene on lipopolysaccharide (LPS) biosynthesis and release by Escherichia coli and Salmonella typhimurium was investigated . Similar results were obtained with both species . The incorporation of {3H}galactose into LPS by galE mutants was inhibited by at least 50% (as compared with normal growing controls) during amino acid deprivation of relA+ strains . This inhibition could be prevented by the treatment of the amino acid-deprived relA+ bacteria with chloramphenicol, a known antagonist of the stringent control mechanism . Furthermore, LPS biosynthesis was not inhibited during amino acid deprivation of isogenic relA mutant strains . These results indicate that LPS synthesis is regulated by the stringent control mechanism . Normal growing cells of both relA+ and relA strains released LPS into the culture fluid at low rates . Amino acid deprivation stimulated the rate of LPS release by relA mutants but not by relA+ bacteria . Chloramphenicol treatment markedly stimulated the release of cell-bound LPS by amino acid-deprived relA+ cells . Thus, a low rate of LPS release was characteristic of normal growth and could be increased in nongrowing cells by relaxing the control of LPS synthesis.

J Bacteriol, 1986 Oct, 168(1), 322 - 7
Cloning and characterization of the cysAMK region of Salmonella typhimurium; Hulanicka MD et al.; A total of 30 kilobases of DNA comprising the cysAMK region of S . typhimurium was cloned as a series of fragments in phage lambda 1059 . The genetic organization of this region was established through studies of gene expression from fragments subcloned in pBR322 and from blot hydridization analyses of restriction sites in chromosomal DNA from multisite deletion strains . The results give a gene order of cysA-cysM-crr-ptsl-ptsH-cysK over a distance of approximately 12 kilobases . cysM and cysA have been cloned and expressed in pBR322; attempts to obtain stable pBR322 derivatives carrying cysK were unsuccessful.

J Bacteriol, 1986 Oct, 168(1), 109 - 14
Export of glutathione by some widely used Salmonella typhimurium and Escherichia coli strains; Owens RA et al.; Significant levels of extracellular glutathione (GSH) were detected in aerobically grown cultures of some strains of Salmonella typhimurium LT-2 and in Escherichia coli K-12, B, and B/r but not in cultures of nine freshly isolated clinical isolates of E . coli . Cultures of S . typhimurium generally contained less total GSH (intracellular plus external) than did E . coli cultures . S . typhimurium TA1534 contained about 2 mM intracellular GSH and exported about 30% of its total GSH . The external GSH concentration increased logarithmically during exponential growth and peaked at about 24 microM in early-stationary-phase cultures . External accumulation of GSH was inhibited by 30 mM NaN3 . GSH was predominantly exported in the reduced form . Two-dimensional paper chromatography of supernatants from cultures labeled with Na2(35)SO4 confirmed the presence of GSH and revealed five other sulfur-containing compounds in the media of S . typhimurium and E . coli cultures . The five unidentified compounds were not derivatives of GSH.

Infect Immun, 1986 Oct, 54(1), 1 - 8
Protection of C3H/HeJ mice from lethal Salmonella typhimurium LT2 infection by immunization with lipopolysaccharide-lipid A-associated protein complexes; Killion JW et al.; C3H/HeJ mice were immunized intraperitoneally (i.p.) with lipopolysaccharide (LPS)-lipid A-associated protein (LAP) complexes or with purified protein-free LPS prior to lethal i.p . or intravenous Salmonella typhimurium LT2 challenge . Our results demonstrated that these Salmonella-hypersusceptible mice can be effectively protected against 1,000 100% lethal doses of S . typhimurium LT2 (i.e., 1,000 viable bacteria) administered by intravenous challenge when previously immunized with LAP-LPS complexes . In contrast to these results, immunization with LPS afforded markedly less protection regardless of the route of challenge, thus suggesting that the LAP portion of LAP-LPS complexes may be necessary for inducing protection against Salmonella infections . For most experiments, antigens were emulsified in complete Freund adjuvant (CFA); however, the CFA portion of the vaccine was suggested not to be an essential component for the induction of immunity to Salmonella infections, since equivalent levels of protection were obtained when it was omitted from the vaccine . The induction of immunity to murine salmonellosis by prior immunization with CFA-LAP-LPS was demonstrated not to be a transient phenomenon, since C3H/HeJ mice were still protected against lethal S . typhimurium LT2 challenge as late as 225 days postimmunization.

Dis Colon Rectum, 1986 Oct, 29(10), 671 - 2
Salmonella typhimurium infection after colectomy with mucosal proctectomy, a pouch, and ileoanal anastomosis; Lontoft E; Severe Salmonella typhimurium infection is described in a patient who was treated previously for ulcerative colitis by total colectomy and mucosal proctectomy with a pouch and ileoanal anastomosis.

Protein Eng, 1986 Oct-Nov, 1(1), 59 - 65
The cloning and expression of an anti-peptide antibody: a system for rapid analysis of the binding properties of engineered antibodies; Roberts S et al.; The cloning of the light and heavy chain genes of an antilysozyme monoclonal antibody is described and the application of site-directed mutagenesis for reconstruction of complete cDNAs from incomplete cDNA clones is discussed . The behaviour of the RNA transcripts produced from these cDNAs after their subcloning into an appropriate Salmonella typhimurium, SP6, vector and subsequent injection into Xenopus oocytes has been analysed . The antibody secreted by oocytes after RNA injection has been quantitated and its antigen-binding properties compared with wild-type hybridoma antibody . The results show that this route for expression of antibodies, though limited in its capacity to produce more than a few micrograms of protein, is potentially a means for rapid evaluation of the antigen-binding properties of engineered antibodies.

J Immunogenet, 1986 Oct-Dec, 13(5-6), 451 - 7
Genes within the major histocompatibility complex influence the response to ampicillin therapy and severity of relapse in H-2 congenic, susceptible Itys mice infected with virulent Salmonella typhimurium; Maskell DJ et al.; Control by genes within H-2 of natural resistance to fully virulent salmonellae in susceptible mice was studied by the typhoid relapse model . Susceptible (Itys), H-2 congenic C57BL/10 (B10) lines were infected with a lethal dose of the virulent S . typhimurium C5 and rescued from death by ampicillin therapy, inducing a chronic infection . The response to therapy and its cessation, both early and late in the infection, varied in different strains . B10 (H-2b) and B10.D2 (H-2d) responded less well to therapy, and were more prone to relapse on its removal, than B10.A (H-2a) or B10.M (H-2f) mice . This haplotype distribution is the same as that previously reported for H-2 linked resistance and susceptibility of similar mice to salmonellae of low virulence . The results indicate that resistance to a virulent salmonella capable of causing natural infection is influenced by genes within the MHC.

Res Commun Chem Pathol Pharmacol, 1986 Oct, 54(1), 101 - 13
The mutagenicity of aflatoxin Q1 to Salmonella typhimurium TA 100 with or without rat or human liver microsomal preparations; Yourtee DM et al.; An investigation of the mutagenicity of aflatoxin Q1 in the Salmonella-mutagenicity test is reported . This mammalian metabolite of aflatoxin B1 was marginally mutagenic to strain TA 98 when either rat or human liver microsomes were present in the test . However, it was mutagenic to TA 100 with the same liver activation sources in the assay . Moreover, it was mutagenic to TA 100 in the absence of liver microsomes . This Q1 mutagenesis, presumably a direct acting base substitution effect, was nearly equal to the liver activated mutagenesis . It was also greater in this respect than aflatoxin B1 or aflatoxicol.

Mutat Res, 1986 Oct, 175(2), 47 - 50
Suppressive effects of coffee on the SOS responses induced by UV and chemical mutagens; Obana H et al.; SOS-inducing activity of UV or chemical mutagens (AF-2, 4NQO and MNNG) was strongly suppressed by instant coffee in Salmonella typhimurium TA1535/pSK1002 . As decaffeinated instant coffee showed a similarly strong suppressive effect, it would seem that caffeine, a known inhibitor of SOS responses, is not responsible for the effect observed . The suppression was also shown by freshly brewed coffee extracts . However, the suppression was absent in green coffee-bean extracts . These results suggest that coffee contains some substance(s) which, apart from caffeine, suppresses SOS-inducing activity of UV or chemical mutagens and that the suppressive substance(s) are produced by roasting coffee beans.

Carcinogenesis, 1986 Oct, 7(10), 1729 - 32
Inhibition of benzo{a}pyrene-dependent mutagenesis and cytochrome P-450 reductase activity by copper complexes; Reiners JJ Jr et al.; The superoxide dismutase (SOD) biomimetic copper(II) (3,5-diisopropylsalicylate)2 (CuDIPS) has been previously reported to inhibit the tumorigenicity of a polycyclic aromatic hydrocarbon (PAH) requiring metabolic activation . We have used the Ames Salmonella typhimurium revertant assay to survey the effects of CuDIPS and its analogs on the metabolic activation of the PAH benzo{a}pyrene (BP) by liver homogenates . Supplementation of homogenates from normal and Aroclor 1254-treated SENCAR mice with varied concentrations of CuDIPS resulted in a dose-dependent noncompetitive inhibition of BP mutagenesis . Cytochrome P-450 reductase activity in liver homogenates and microsomal preparations was also inhibited by concentrations of CuDIPS possessing antimutagenic activity . Neither DIPS nor ZnDIPS, analogs of CuDIPS lacking SOD activity, inhibited mutagenesis or P-450 reductase activity . CuSO4, which has SOD activity, was almost as effective as CuDIPS on a molar basis in inhibiting mutagenesis and P-450 reductase activity . The inhibitory effects of CuDIPS and CuSO4 could not be attributed to their SOD activity since bovine liver superoxide dismutase, at a 100-fold excess of CuDIPS-SOD activity, had no effect on their activity . Collectively these findings suggest that the in vitro antimutagenic activity of CuDIPS is independent of its salicylate structure and is mediated through a copper-dependent but non SOD-associated inhibition of P-450 reductase activity.

J Antimicrob Chemother, 1986 Oct, 18 Suppl C, 183 - 8
Antibiotic resistance profiles and molecular epidemiology of Salmonella typhimurium and S . dublin, mainly from cattle; Jorgensen ST; Among 130 strains of Salmonella typhimurium and 191 strains of S . dublin, all isolated from cattle in the early 1980s, 80% and 63%, respectively, were resistant to one or more (up to three) antibiotics . Monoresistance to sulphonamides was most common . In 169 strains of the two serotypes from 1985 the antibiotic resistance load was of a similar size . The latter batch was not studied with respect to plasmids . In the strains from 1980 and 1981 the plasmid load was analysed by conjugation, transformation, extraction of plasmid DNA and subsequent electrophoresis in agarose gels . Plasmid DNA from 38 strains was further analysed by restriction with endonuclease EcoRI . On the basis of this the strains were classified into four groups: two of S . typhimurium, one of S . dublin and one group of both serotypes . This suggested that dissemination of strains and plasmids mainly occurred through clonal spread of strains.

J Hyg (Lond), 1986 Oct, 97(2), 193 - 7
Recognition of the cryptic plasmid, pSLT, by restriction fingerprinting and a study of its incidence in Scottish Salmonella isolates; Brown DJ et al.; The plasmid pSLT is a cryptic plasmid of 60 megadaltons (Md) present in Salmonella typhimurium LT2 . We present evidence that it has a characteristic fingerprint when digested with the restriction enzymes PstI and SmaI . Among a representative collection of S . typhimurium isolates it was present in 67% of strains and was widely distributed amongst different phage types (DT) with the exception of DT10 and U285 . Furthermore, its prevalence among veterinary isolates was significantly higher than among human isolates . It was not found among any of the 96 strains representative of other salmonella serotypes currently prevalent and thus appears to be serotype-specific.

Genetics, 1986 Oct, 114(2), 633 - 57
A quantitative model for nonrandom generalized transduction, applied to the phage P22-Salmonella typhimurium system; Mandecki W et al.; A mathematical model for nonrandom generalized transduction is proposed and analyzed . The model takes into account the finite number of transducing particle classes for any given marker . The equations for estimation of the distance between markers from contransduction frequency data are derived and standard errors of the estimates are given . The obtained relationships depend significantly on the number of classes of transducing fragments . The model was applied to estimate the number of transducing fragment classes for a given marker in transduction with phage P22 of Salmonella typhimurium . It was found that the literature data on frequencies of contransduction in crosses with mutual substitution of selective and nonselective markers can be rationalized most accurately by assuming that the mean number of classes is equal to 2 . An improved method for analysis of cotransduction data is proposed on the basis of our model and the results of calculation . The method relies on solving a set of algebraic equations for cotransduction frequencies of markers located within one phage length . The method allows a relatively precise determination of distances between markers, positions of transducing particle ends and deletion or insertion lengths . The approach is applied to the trp-cysB-pyrF and aroC-hisT-purF-dhuA regions of the Salmonella typhimurium chromosome.

Chem Biol Interact, 1986 Oct 1, 59(3), 309 - 24
Aerobic and anaerobic reduction of nitrated pyrenes in vitro; Djuric Z et al.; Nitrated pyrenes are mutagenic and tumorigenic environmental pollutants that are activated to DNA-binding derivatives via nitroreduction . We have investigated the enzymatic nitroreduction of 1-nitropyrene, 1,3-, 1,6- and 1,8-dinitropyrene to determine if differences in the extent of nitroreduction may help explain differences in their biological potencies . Each nitrated pyrene was incubated aerobically and anaerobically with 105,000 X g supernatant (S105) from Salmonella typhimurium TA98 and the nitroreductase-deficient strain, TA98NR, and with cytosol and microsomes from rat and human liver . Under anaerobic conditions, 1-nitropyrene and 1,3-dinitropyrene were reduced by TA98 S105 to a lesser extent than 1,6- and 1,8-dinitropyrene . The extent of 1,6- and 1,8-dinitropyrene metabolism was not altered relative to TA98 when using TA98NR S105, but the nitroreduction of 1-nitropyrene and 1,3-dinitropyrene was decreased . Both rat and human liver cytosol and microsomes reduced 1,6- and 1,8-dinitropyrene to greater extents than 1-nitropyrene and 1,3-dinitropyrene . Under aerobic conditions rat and human liver cytosols were similar to TA98 S105 in that aminopyrene decreased while nitrosopyrene formation increased . By comparison, oxygen decreased the microsomal formation of both nitrosopyrenes and aminopyrenes . The reduction of succinoylated cytochrome c was measured during the hepatic metabolism of nitro- and nitrosopyrenes under aerobic conditions . The data indicated that reduced nitro- and nitrosopyrene intermediates were directly reducing succinoylated cytochrome c and that the assay could be used as a measure of aerobic nitroreduction . These studies demonstrate that 1,6- and 1,8-dinitropyrene are reduced to a greater extent than 1-nitropyrene and 1,3-dinitropyrene, which corresponds to their relative biological potencies as mutagens and carcinogens . Furthermore, although more extensive nitroreduction is detected under anaerobic conditions, the nitroreduction that occurs aerobically may be important for the mutagenic and tumorigenic properties of these compounds.

J Bacteriol, 1986 Oct, 168(1), 405 - 11
Effects of anaerobic regulatory mutations and catabolite repression on regulation of hydrogen metabolism and hydrogenase isoenzyme composition in Salmonella typhimurium; Jamieson DJ et al.; Hydrogen metabolism in Salmonella typhimurium is differentially regulated by mutations in the two anaerobic regulatory pathways, defined by the fnr (oxrA) and oxrC genes, and is controlled by catabolite repression . The synthesis of the individual hydrogenase isoenzymes is also specifically influenced by fnr and oxrC mutations and by catabolite repression in a manner entirely consistent with the proposed role for each isoenzyme in hydrogen metabolism . Synthesis of hydrogenase isoenzyme 2 was found to be fnr dependent and oxrC independent, consistent with a role in respiration-linked hydrogen uptake which was shown to be similarly regulated . Also in keeping with such a respiratory role was the finding that both hydrogen uptake and the expression of isoenzyme 2 are under catabolite repression . In contrast, formate hydrogenlyase-dependent hydrogen evolution, characteristic of fermentative growth, was reduced in oxrC strains but not in fnr strains . Hydrogenase 3 activity was similarly regulated, consistent with a role in hydrogen evolution . Unlike the expression of hydrogenases 2 and 3, hydrogenase 1 expression was both fnr and oxrC dependent . Hydrogen uptake during fermentative growth was also both fnr and oxrC dependent . This provided good evidence for a distinction between hydrogen uptake during fermentation- and respiration-dependent growth and for a hydrogen-recycling process . The pattern of anaerobic control of hydrogenase activities illustrated the functional diversity of the isoenzymes and, in addition, the physiological distinction between the two anaerobic regulatory pathways, anaerobic respiratory genes being fnr dependent and enzymes required during fermentative growth being oxrC dependent.

Zh Mikrobiol Epidemiol Immunobiol, 1986 Oct, (10), 3 - 8
{Isolation and characteristics of the biological and genetic properties of neamin-resistant mutants of Salmonella typhimurium and Salmonella dublin candidates for vaccine creation}; Marakusha BI et al.; Mutants, resistant to neamine and spectinomycin, have been isolated from S . typhimurium and S . dublin highly virulent strains . The neamine-resistant mutants can be divided into 3 classes in accordance with their sensitivity to streptomycin: sensitive, resistant to low and high concentrations of this antibiotic . The transduction analysis with the use of bacteriophage P 22 has revealed that the spectinomycin-resistant mutations under study are spc A mutations, while the mutations leading to resistance to neamine in class Near Strr 500 are nea B mutations . The mutation leading to resistance to spectinomycin (spc A) has been found to produce no changes in the virulence of salmonellae in the intraperitoneal infection of mice . The mutations leading to resistance to neamine and streptomycin (nea B and str A) have been found to decrease virulence.

Microb Pathog, 1986 Oct, 1(5), 433 - 41
Evidence for the importance of O antigen specific antibodies in mouse-protective Salmonella outer membrane protein (porin) antisera; Saxen H et al.; The antibodies responsible for the protective effect of sera obtained by immunizing rabbits with the major outer membrane protein porin of Salmonella typhimurium complexed with LPS (Kuusi et al., Infect . Immun., 1981; 34:328-332) were found to be directed to the O antigen . They were effective in very small concentration which probably accounted for our failure to identify them before or now by in vitro methods . Although both the porin and the LPS in the complexes used for immunization were isolated from rough (R) form organisms devoid of O antigen by all usually applied criteria, the antigen contained a small amount of smooth form LPS, most probably derived from a slight leakiness of the rfa mutation responsible for the R character . The small amount of contaminating O antigen was apparently rendered highly immunogenic by complexation with the outer membrane protein.

Toxicol Appl Pharmacol, 1986 Sep 30, 85(3), 355 - 66
Microsomal activation of fluoranthene to mutagenic metabolites; Babson JR et al.; The in vitro metabolism of fluoranthene (FA) was assessed by incubating 3-{3H}FA, the synthesis of which is described, with rat hepatic microsomal enzymes . Several metabolites including the FA 2,3-diol, FA 2-3,-quinone, 3-OH-FA, 1-OH-FA, and 8-OH-FA were isolated by high-pressure liquid chromatography and identified by comparison of chromatographic properties and uv-visible spectra with those of synthetic standards . The major metabolite produced over the FA concentration range studied (23-233 microM) was FA 2,3-diol, accounting for 29-43% of the total extractable metabolites . This diol was characterized further by high-resolution mass spectroscopy and H-NMR and determined to be identical in structure to the trans-2,3-dihydroxy-2,3-dihydrofluoranthene . The FA 2,3-diol, syn and anti 2,3-diol-1,10b-epoxides, FA 2,3-quinone, and FA 7,8-diol were all shown to be mutagenic toward Salmonella typhimurium TM677 . The FA 1,10b-diol and syn and anti FA 1,10b-diol-2,3-epoxides were not mutagenic . The epoxide hydrolase inhibitor, 3,3,3-trichloropropylene oxide, markedly reduced the mutagenic potency of FA while concurrently inhibiting FA 2,3-diol production but not overall FA metabolism . These results suggests that a major metabolic activation pathway of FA resulting in the production of mutagenic species involves the formation of the FA 2,3-diol and the subsequent oxidation of this diol to a FA 2,3-diol-1,10b-epoxide . Another minor activation pathway with mutagenic endpoints may involve the formation of the 7,8-diol.

J Mol Biol, 1986 Sep 5, 191(1), 39 - 58
Novel regulatory mutants of the phosphate regulon in Escherichia coli K-12; Wanner BL; New pleiotropic mutants were isolated that express either the phoA, psiE or psiO promoter constitutively and simultaneously alter bacterial alkaline phosphatase regulation, carbon utilization or ultraviolet light sensitivity . To do this, Lac+ mutants were isolated from strains with the appropriate lacZ transcriptional fusions . Over 300 independent mutants were characterized, and all that constitutively express phoA map in phoR, phoU, the phosphate-specific transport system or a new locus called phoF . However, only phoU mutants express both phoA and psiE constitutively . Carbohydrate-utilizing mutants that show constitutive expression of psiE and psiO map in cya, crp and, possibly, crr . Also, numerous ultraviolet-light-sensitive mutants were discovered that show increased psiO expression and map in lon . Some other mutations that lead to constitutive psiO expression (which is normally induced either by phosphate, nitrogen or carbon starvation or anoxia) show decreased expression of phoA . Also, several mutants were found that show an unusual metastable character affecting psiO or phoA transcription . In these, colonies spontaneously switch between an induced and repressed "state" with respect to lac or bacterial alkaline phosphatase expression . In some, the clonal variation of the lactose phenotype or bacterial alkaline phosphatase synthesis is recA-independent and phenotypically resembles phase variation in Salmonella typhimurium . The latter class are called "phase mutants" . The mutants are discussed in terms of protein-nucleic acid interactions and/or possible changes in the DNA, i.e . modifications or rearrangements, within the phosphate gene system, that are physiologically regulated.

Carcinogenesis, 1986 Sep, 7(9), 1561 - 7
Modulation of cytotoxic and genotoxic effects of 2-acetylaminofluorene in rat and hamster hepatocytes by 3-methylcholanthrene pre-treatment; Holme JA et al.; It is well known that 2-acetylaminofluorene (AAF)-induced liver cancer is reduced by simultaneous administration of 3-methylcholanthrene (MC) in the rat, but not in the hamster . The present report examines the effects of MC pre-treatment on the metabolism and toxicity of AAF in monolayer cultures of hepatocytes . Hepatocytes isolated from pre-treated animals of both species metabolized AAF and 2-aminofluorene (AF) to metabolites mutagenic to Salmonella typhimurium more efficiently than hepatocytes from control animals . MC-pre-treated rat hepatocytes showed increased responses to AAF- and AF-induced unscheduled DNA synthesis, while MC-pre-treated hamster hepatocytes were less responsive than the untreated hepatocytes . Increased cytotoxic effects of AAF were observed in MC-pre-treated rat hepatocytes, whereas AAF was not cytotoxic in hamster hepatocytes from either pre-treated or control animals . MC pre-treatment caused increased rates of formation of C-hydroxylated, N-hydroxylated, water-soluble and covalently macromolecular bound AAF metabolites in both species . No significant effect of MC pre-treatment was seen on the formation of AF from AAF . A large decrease in the ratio between covalently macromolecular bound (activated) metabolites and the sum of C-hydroxylated and water-soluble (detoxified) AAF metabolites, was seen after MC pre-treatment of rat hepatocytes, whereas no or only a minor decrease was observed in hamster hepatocytes . This ratio correlated much better with the in vivo carcinogenicity data than the other parameters such as mutagenicity, DNA repair or covalent macromolecular binding . Thus, the hypothesis that AAF-induced liver cancer depends less on the rate at which AAF is activated, but more on the relative proportion of the dose which is activated, is supported by the present data.

J Nat Prod, 1986 Sep-Oct, 49(5), 866 - 71
Mutagenic perylenequinone metabolites of Alternaria alternata: altertoxins I, II, and III; Stack ME et al.; The mold genus Alternaria is a widely distributed plant pathogen . Some of these species, e.g., A . alternata, are common decay organisms of fruits and vegetables . Two novel perylene oxide metabolites, altertoxins II and III, have been identified in extracts of A . alternata isolates that exhibit mutagenic responses in the Ames Salmonella typhimurium assay . These identifications were based on mass, optical rotational, and 1H- and 13C-nmr spectral studies . Previous reports of related perylene dione mycotoxins have been clarified.

Food Chem Toxicol, 1986 Sep, 24(9), 987 - 8
Salmonella/microsome mutagenicity tests of heat-processed milk samples; Sekizawa J et al.; Samples of whole milk were heat treated by commercial heat-sterilization, by commercial heat-pasteurization or by a laboratory heat-pasteurization (65 degrees C for 30 min) . Each sample was tested for mutagenicity in Salmonella typhimurium strains TA98 and TA100 with and without S-9 mix . Dichloromethane extracts of milk heated at 100, 135 and 150 degrees C for 5 hr were also tested for mutagenicity using the same assay . None of these samples exhibited mutagenicity in the Ames assay used.

Bioorg Khim, 1986 Sep, 12(9), 1181 - 4
{Sensitivity of mannosyl transferases from Salmonella serotype E1 and B to modification of the donor heterocyclic base}; Druzhinina TN et al.; A series of synthetic nucleoside diphosphate mannoses with different heterocyclic bases were tested as GDP-Man analogues in enzymatic mannosylation during assembly of O-antigen repeating units of Salmonella anatum and Salmonella typhimurium . The substrate efficiency was found to depend strongly on oxygen atom presence at C6 of the purine residue, the H2N-C2-N1-H grouping of the heterocyclic nucleus being less important . UDP-Man proved to be an efficient substrate for the mannosylation reactions.

Genetika, 1986 Sep, 22(9), 2265 - 71
{Study of promutagen biotransformation in the Ames test . IV . The effect of transplanted tumors on the biotransformation of various antineoplastic agents}; Oblapenko NG et al.; The effect of transplantation of rat tumours Jensen sarcoma, sarcoma 45, sarcoma M-1, as well as of inoculation of rat normal connective tissue on the processes of biotransformation of antitumour preparations cyclophosphane (CP), thiophosphamide, prospidine and of model compound nitrosomorpholine (NM) was studied . The study was accomplished by means of the Ames test with indicator bacterial strain Salmonella typhimurium TA 1950 in relation to the reactions of the 1st and the 2nd phases of xenobiotics metabolism . It was shown that the presence of tumours leads to inhibition of both metabolic activation processes of the promutagens NM and CP and the conjugation reactions of genetically active metabolites of these compounds with reduced glutathione . Genetic danger is supposed to be increased during application of antitumour preparations, the mutagenic activity of which is due to the activity of their metabolites . It is noted that the most essential effect on biotransformation processes of NM and CP was exhibited by sarcoma M-1, the most important changes of the biotransformation processes of promutagens being observed in the initial period of pathologic process, i.e . on the 3rd day after inoculation . Transplantation of the normal connective tissue of rats had no effect on reactions of both the 1st and the 2nd phase of metabolism of the promutagens studied.

Genetika, 1986 Sep, 22(9), 2259 - 64
{Study of promutagen biotransformation in the Ames test . III . The role of conjugation with glucuronic acid and sulfate in the modification of mutagenic effect of nitrosomorpholine, diethylnitrosamine and cyclophosphamide}; Loknitskaia NN et al.; The role of reactions of conjugation with uridine diphosphoglucuronic acid (UDPGA) and with 3-phosphoadenosine-5-phosphosulfate (PAPS) in modification of the mutagenic effect of diethyl nitrosamine (DENA), nitrosomorpholine (NM) and cyclophosphane (CP) was studied by the Ames test . It was shown that adding UDPGA to the activating mixture significantly decreased the level of the mutagenic effect of DENA, NM and CP on bacteria Salmonella typhimurium TA 1950, when S9 and microsomal fractions of rat liver homogenate were used . Adding PAPS to the activating mixture when S9 and cytosole fractions were used, did not affect mutagenic action of DENA on S . typhimurium TA 1950 and TA 1535, enhancing the mutagenic effect of CP on TA 1535, with no such influence on TA 1950 . Introduction of PAPS into the activating mixture elevated the mutagenic effect of NM on both bacterial strains using S9 fraction but not cytosole fraction.

Mutat Res, 1986 Sep, 168(2), 69 - 240
The Salmonella typhimurium/mammalian microsomal assay . A report of the U.S . Environmental Protection Agency Gene-Tox Program; Kier LD et al.; The Salmonella assay has been in use for almost 15 years and can be defined as a routine test for mutagenicity and for predicting potential carcinogenicity . It detects the majority of animal carcinogens and consequently plays an important role in safety assessment . The test is also routinely used as the frontline screen for environmental samples (complex mixtures) isolated from air, water and food . This role will continue to remain an area of growth as or because sample volumes associated with these testing areas are generally very limited and more extensive testing is generally impossible . While this test, like all others, has some limitations, it is recommended that it be regularly included in all genetic testing batteries.

J Med Microbiol, 1986 Sep, 22(2), 119 - 23
Spontaneous deletions of drug-resistance determinants from Salmonella typhimurium in Escherichia coli; Roy S et al.; Plasmids isolated from two different clinical isolates of Salmonella typhimurium, both resistant to the antibiotics ampicillin, tetracycline, streptomycin and chloramphenicol, were used to transform Escherichia coli . Segregation of antibiotic-resistance determinants occurred in both cases . Analysis of plasmids from one set of segregants by DNA-DNA hybridisation indicated that the segregation was due to precise deletions in the transforming plasmid.

Cancer Res, 1986 Sep, 46(9), 4556 - 65
Mutagenic and cell-transforming activities of triol-epoxides as compared to other chrysene metabolites; Glatt H et al.; The syn- and anti-isomers of the bay-region diol-epoxides of chrysene and of 3-hydroxychrysene and their metabolic precursors have been investigated for mutagenicity in Salmonella typhimurium (reversion to histidine prototrophy) and V79 Chinese hamster cells (acquirement of resistance to 6-thioguanine) and for transforming activity in M2 mouse prostate cells . Other known and potential chrysene metabolites have been included in mutagenicity experiments . Direct mutagenic activity in S . typhimurium TA 100 exhibited, in order of potency, anti-triol-epoxide greater than syn-triol-epoxide greater than anti-diol-epoxide greater than syn-diol-epoxide greater than chrysene 5,6-oxide much greater than chrysene-1,2-quinone, chrysene-3,4-quinone, and chrysene 5,6-quinone . Chrysene, the six isomeric chrysenols, and the trans-dihydrodiols {trans-1,2-dihydroxy-1,2-dihydrochrysene (chrysene-1,2-diol), trans-3,4-dihydroxy-3,4-dihydrochrysene, trans-5,6-dihydroxy-5,6-dihydrochrysene, and 9-hydroxy-trans-1,2-dihydroxy-1,2-dihydrochrysene (9-hydroxychrysene-1,2-diol)} were inactive per se but were activated to mutagens in the presence of reduced nicotinamide adenine dinucleotide phosphate-fortified postmitochondrial fraction (S9 mix) of liver homogenate from Arochlor 1254-treated rats . Chrysene, 3-hydroxychrysene, chrysene-1,2-diol, and 9-hydroxychrysene-1,2-diol were activated efficiently; the other compounds were activated weakly . In S . typhimurium TA 98, the mutagenic activities of the chrysene derivatives were weak in comparison with those in the strain TA 100 . trans-3,4-Dihydroxy-3,4-dihydrochrysene (in the presence of S9 mix) was the most efficacious mutagen in strain TA 98 . The relative mutagenic potencies of the directly active compounds differed from the results obtained in strain TA 100, in that in strain TA 98 the anti-diol-epoxide was more mutagenic than the triol-epoxides and chrysene 5,6-oxide was more mutagenic than syn-diol-epoxide and syn-triol-epoxide . In V79 cells, the order of mutagenic potency was: anti-triol-epoxide greater than anti-diol-epoxide greater than syn-triol-epoxide greater than syn-diol-epoxide greater than chyrsene 5,6-oxide greater than chrysene-1,2-diol (in the presence of S9 mix) greater than 9-hydroxychrysene-1,2-diol (in the presence of S9 mix) greater trans-3,4-dihydroxy-3,4-dihydrochrysene in the presence of S9 mix) . Chrysene, 3-hydroxychrysene, 5-hydroxychrysene, and 6-hydroxychrysene showed no mutagenic effects in V79 cells, either in the presence or absence of S9 mix.(ABSTRACT TRUNCATED AT 400 WORDS)

Cell Biol Toxicol, 1986 Sep, 2(3), 341 - 55
Formation of reactive 1-nitropyrene metabolites by lung microsomes and isolated lung cells; Dybing E et al.; The metabolism and activation of 1-nitropyrene (1-NP) to reactive intermediates by lung microsomes and isolated lung cells was studied . Mutagenicity of 1-NP metabolites was assayed in Salmonella typhimurium TA98NR, a strain lacking a major component of nitroreductase activity . In the presence of NADPH, microsomes from rabbit, rat and hamster lung metabolized 1-NP to mutagenic products to a similar degree . Pretreatment with a mixture of polychlorinated biphenyls (PCB) decreased the formation of mutagenic metabolites by rabbit lung microsomes, but did not affect the production of mutagens by rat or hamster lung microsomes . 3H-1-NP was metabolized to covalently bound protein products at a rate of 82 and 10 pmol/mg by rabbit and hamster lung microsomes, respectively, whereas no binding was detected in rat lung microsomes . PCB-pretreatment increased covalent protein binding of 3H-1-NP in lung microsomes from hamster and rat, but decreased the binding in rabbit lung microsomes . High performance liquid chromatography analysis indicated that 3H-1-NP was readily converted to ring-hydroxylated products by rabbit and hamster lung microsomes; the rate was much lower with rat lung microsomes . 3H-1-NP was activated to metabolites that covalently bound to protein in isolated rabbit lung cells, with the following rates being observed: Clara cells greater than lung digest greater than type II cells . In contrast, covalent protein binding in cells isolated from rat lung was very low . 1-NP was not activated to products mutagenic for S . typhimurium TA 98NR when co-incubated with cells isolated either from rabbit or rat lung.

Rev Infect Dis, 1986 Sep-Oct, 8(5), 682 - 92
Molecular epidemiology of bacterial infections: examples of methodology and of investigations of outbreaks; Wachsmuth K; Plasmid profile analysis, plasmid and chromosomal bacterial restriction endonuclease DNA analysis, and DNA hybridization are increasingly used in clinical microbiology and epidemiology . These techniques have been applied, singly and in combination, to investigations of outbreaks, including those of diarrheal diseases caused by pandemic Vibrio cholerae, enterotoxigenic and enterohemorrhagic Escherichia coli, Salmonella muenchen, and Salmonella typhimurium . The techniques have been critical in the unraveling of outbreaks of disease caused by nosocomial and community-acquired pathogens . Although there are limitations to these methods, their applications have important ramifications for basic science and public health.

Cancer Lett, 1986 Sep, 32(3), 327 - 34
Use of the human liver cell line Hep G2 in a modified Salmonella reversion assay; Zhuo Z et al.; The human hepatoma cell line Hep G2 was used to activate promutagenic chemicals to mutagens in a modified Salmonella typhimurium reversion assay . Hep G2 cells mediated positive mutagenic responses in tester strain TA98 with 5 and 25 micrograms/plate of 2-aminofluorene, but these responses were consistently lower than those seen using primary rat hepatocytes . In addition, 3 and 6 X 10(6) Hep G2 cells per assay produced positive mutagenic responses with 2-aminoanthracene, benzidine, acetylbenzidine and aflatoxin B1, while benzo{a}pyrene, 7,12-dimethylbenz{a}anthracene, 3-methylcholanthrene, 4-aminobiphenyl and 4- and 11-aminobenzo{a}pyrene were nonmutagenic with Hep G2-cell activation . These results indicate that Hep G2 cells may be a useful intact cellular metabolizing system of human origin for predicting the genotoxicity of promutagenic agents, but that the use of Salmonella as a target cell may limit the classes of mutagens detected.

Proc Natl Acad Sci U S A, 1986 Sep, 83(18), 6805 - 9
Anaerobic regulation of nitrogen-fixation genes in Rhodopseudomonas capsulata; Kranz RG et al.; A Rhodopseudomonas capsulata nifH::lacZ gene fusion was used to isolate constitutive mutants of R . capsulata, unable to repress nif gene transcription anaerobically with every fixed-nitrogen source tested . When these nifc strains were grown aerobically, nif gene transcription was repressed . These results indicate that the regulation of nif gene transcription by fixed nitrogen is different from the regulation by oxygen . Under anaerobic conditions, nif gene transcription in both R . capsulata and Klebsiella pneumoniae is specifically prevented by inhibitors of DNA gyrase {DNA topoisomerase type II (ATP-hydrolyzing), EC 5.99.1.3} . A recent study has shown that anaerobically grown Salmonella typhimurium have high DNA gyrase activity, whereas aerobically grown cells have high DNA topoisomerase type I (EC 5.99.1.2) activity and DNA that is more relaxed {Yamamoto, N . & Droffner, M . L . (1985) Proc . Natl . Acad . Sci . USA 82, 2077-2081} . In view of these results, we suggest that the control of nif gene transcription in response to oxygen is determined by the action of DNA gyrase and DNA topoisomerase I . Thus, although nitrogen control of nif gene expression requires the products of regulatory genes for which constitutive mutations can be isolated, oxygen appears instead to prevent the adoption of a DNA conformation necessary, directly or indirectly, for nif gene transcription.

J Bacteriol, 1986 Sep, 167(3), 1086 - 8
Genetics of NAD metabolism in Salmonella typhimurium and cloning of the nadA and pnuC loci; Tirgari S et al.; The nadA and pnuC loci of S . typhimurium were cloned and found to reside within a 2.2-kilobase region . Two-dimensional O'Farrell gel electrophoresis of the proteins produced after chloramphenicol amplification and subsequent release from chloramphenicol inhibition revealed NadA and PnuC to be 43,000- and 25,000-molecular-weight proteins, respectively . The data indicated that nadA and pnuC represent two distinct genes.

Food Chem Toxicol, 1986 Sep, 24(9), 981 - 5
Mutagenicity studies of selected antihistamines, their metabolites and products of nitrosation; Kammerer RC et al.; Methapyrilene, four structurally related antihistamines, three metabolites of methapyrilene and two products of the reaction of methapyrilene with nitrite were all tested for mutagenicity to Salmonella typhimurium . The two products of the methapyrilene-nitrite reaction have also been identified as metabolites of methapyrilene . None was mutagenic alone, either with or without rat liver S-9 activation . After reaction with sodium nitrite in acetic acid solution (nitrosation), the products of five of the ten compounds were mutagenic . These compounds were methaphenilene, 2-thiophenemethanol, 2-thiophenecarboxylic acid, N-(2-pyridyl)-N'N'-dimethylethylenediamine and N-(2-thenylmethyl)-2-aminopyridine.

J Bacteriol, 1986 Sep, 167(3), 1081 - 2
Exclusion of high-molecular-weight maltosaccharides by lipopolysaccharide O-antigen of Escherichia coli and Salmonella typhimurium; Ferenci T et al.; The barrier properties of lipopolysaccharide were studied by testing the influence of O-antigen on the binding of ligand to maltoporin in the outer membranes of Escherichia coli and Salmonella typhimurium . Maltoporin (LamB protein) of Escherichia coli K-12 was capable of interacting with macromolecular starch polysaccharides, as was previously shown by the binding of intact bacteria to fluorescein-labeled amylopectin or to starch-Sepharose columns . In contrast, strains with complete O-antigenic lipopolysaccharide showed reduced binding to these substrates . A similar result was obtained with Salmonella typhimurium LT2, which did not bind to starch unless rfa mutations removed noncore polysaccharide . The exclusion limit of the lipopolysaccharide permeability barrier to alpha-glucans was tested by measuring the maltoporin-dependent transport of maltose and its inhibition by maltodextrins of various sizes . Only amylopectin (molecular weight, greater than 25,000) was excluded in transport experiments, whereas maltodextrins with molecular weights of up to 2,000 were not excluded by the presence of an O-polysaccharide layer.

Vet Rec, 1986 Aug 30, 119(9), 201 - 3
Salmonella in sewage effluent and the relationship to animal and human disease in the north of Scotland; Johnston WS et al.; During the period July 1982 to December 1984, the presence of salmonella organisms was investigated at weekly intervals in the sewage system and abattoir effluent of a town in the north of Scotland . Three hundred and fifteen isolations, representing 37 different serotypes, were made which included 20 different Salmonella typhimurium phage types and four different S enteritidis phage types . Ten of the serotypes were isolated from livestock in the district during the survey as well as in the periods immediately before and after the survey . There were seven recorded incidents of human infection, involving four salmonella serotypes, only three of which were isolated concurrently from sewage.

Biochemistry, 1986 Aug 26, 25(17), 4778 - 84
A cysteine residue (cysteine-116) in the histidinol binding site of histidinol dehydrogenase; Grubmeyer CT et al.; Salmonella typhimurium L-histidinol dehydrogenase (EC 1.1.1.23), a four-electron dehydrogenase, was inactivated by an active-site-directed modification reagent, 7-chloro-4-nitro-2,1,3-benzoxadiazole (NBD-Cl) . The inactivation followed pseudo-first-order kinetics and was prevented by low concentrations of the substrate L-histidinol or by the competitive inhibitors histamine and imidazole . The observed rate saturation kinetics for inactivation suggest that NBD-Cl binds to the enzyme noncovalently before covalent inactivation occurs . The UV spectrum of the inactivated enzyme showed a peak at 420 nm, indicative of sulfhydryl modification . Stoichiometry experiments indicated that full inactivation was correlated with modification of 1.5 sulfhydryl groups per subunit of enzyme . By use of a substrate protection scheme, it was shown that 0.5 sulfhydryl per enzyme subunit was neither protected against NBD-Cl modification by L-histidinol nor essential for activity . Modification of the additional 1.0 sulfhydryl caused complete loss of enzyme activity and was prevented by L-histidinol . Pepsin digestion of NBD-modified enzyme was used to prepare labeled peptides under conditions that prevented migration of the NBD group . HPLC purification of the peptides was monitored at 420 nm, which is highly selective for NBD-labeled cysteine residues . By amino acid sequencing of the major peptides, it was shown that the reagent modified primarily Cys-116 and Cys-377 and that the presence of L-histidinol gave significant protection of Cys-116 . The presence of a cysteine residue in the histidinol binding site is consistent with models in which formation and subsequent oxidation of a thiohemiacetal occurs as an intermediate step in the overall reaction.

J Biol Chem, 1986 Aug 15, 261(23), 10814 - 20
Kinetics of receptor modification . The multiply methylated aspartate receptors involved in bacterial chemotaxis; Terwilliger TC et al.; A method for determining the extent of methyl esterification of each of the four potential sites on the aspartate receptors involved in chemotaxis in Escherichia coli and Salmonella typhimurium is presented . In this procedure, radioactive methyl esters are incorporated into the receptors, the receptors are cleaved by trypsin and the V8 protease from Staphylococcus aureus, and the four fragments containing sites of methylation are separated by high performance liquid chromatography . Using this technique, we find that the rate of methyl esterification increases at all four sites after stimulation with the "attractant" aspartate, suggesting that all four sites of modification are involved in adaptation to aspartate . We also find that the rate of methyl esterification at each site is correlated with the homology between the protein sequence at that site and the "consensus" sequence, Glu-Glu-X-X-Ala-Thr/Ser.

J Toxicol Sci, 1986 Aug, 11(3), 197 - 211
{Toxicological studies on sophorolipid derivatives . (I) . Acute toxicity, eye irritation, primary skin irritation, skin sensitization, phototoxicity, photosensitization, mutagenicity of polyoxypropylene (12) {(2'-0-beta-D-glucopyranosyl-beta-D-glucopyranosyl)oxy-} fatty acid ester-}; Ikeda Y et al.; Acute toxicity, eye irritation, primary skin irritation, skin sensitization, phototoxicity, photosensitization and mutagenicity of sophorolipid derivatives were studied in rats, mice, rabbits, guinea pigs and Salmonella typhimurium strains . The acute oral toxicity of sophorolipid (SL) which Torulopsis bombicola produces, and its derivatives (PSL, Ethyl-SL and Oleyl-SL) were shown to be very low . The LD50 values of PSL ranged from 10 g/kg to 16 g/kg on oral administration in rats and mice, and from 5.8 g/kg to 6.6 g/kg on subcutaneous administration in mice . The oral LD50 values of Ethyl-SL and Oleyl-SL were estimated to be greater than 15 g/kg and that of SL was 12.5 g/kg . In eye irritation study, PSL failed to produce any reactions at 50% concentration even when the rabbit eye was not subsequently washed . SL, Ethyl-SL, Oleyl-SL and Tween 20 were "no irritant" or "slight irritant" to the rabbit eye at 20% concentration . PSL showed no irritancy to both the intact and abraded guinea pig skin at 50% concentration . And in other examinations, it was also indicated that PSL had no potentials of skin sensitization, phototoxicity and photosensitization in guinea pigs and had no potentials of mutagenicity in Salmonella typhimurium TA98 and TA100.

Environ Health Perspect, 1986 Aug, 67, 89 - 91
Mutagens in coffee and other beverages; Nagao M et al.; A cup of coffee contains mutagens which produce about 5 X 10(4)-10(5) revertants of Salmonella typhimurium TA 100 without S9 mix . One of the mutagens was identified to be methylglyoxal . Methylglyoxal was present in various beverages such as black tea, whisky, and brandy . Methylglyoxal itself induced tumors in rats when administered by subcutaneous injection . However, the mutagenic properties of coffee were different from those of methylglyoxal . The mutagenicity of coffee was suppressed by catalase, and coffee was found to contain hydrogen peroxide . Furthermore, coffee solution was found to have a hydrogen peroxide-generating system . Instant coffee (15 mg/mL) contains 130 microM hydrogen peroxide immediately after the dissolution of coffee powder in water at room temperature . The concentration of hydrogen peroxide increased with time . The mutagenicity of methylglyoxal was increased by the copresence of hydrogen peroxide . A maximum of 30-fold enhancement was observed . The mutagenicity of black tea but not that of whisky was suppressed by catalase.

Environ Health Perspect, 1986 Aug, 67, 121 - 7
Genotoxicity, carcinogenicity, and mode of action of the fried food mutagen 2-amino-3-methylimidazo{4,5-f}quinoline (IQ); Weisburger JH et al.; Because mutagens typified by 2-amino-3-methylimidazo{4,5-f}quinoline (IQ) observed in cooked foods are widely consumed, detailed studies of their biochemical and biological properties including carcinogenicity are most important . IQ induces unscheduled DNA synthesis in liver cells, which when taken together with its powerful mutagenicity in the Salmonella typhimurium test system, predicts carcinogenicity . In female Sprague-Dawley rats, IQ did exhibit potent carcinogenicity for the mammary gland, the ear duct, and to a lesser extent, pancreas and bladder . Data from Japanese laboratories indicate carcinogenicity also to the intestinal tract . Thus, one of the mutagens formed during cooking is a versatile carcinogen that because of extensive human intake requires urgent exploration for specific human cancer risk.

Environ Health Perspect, 1986 Aug, 67, 111 - 6
Hydroxylation of guanine in nucleosides and DNA at the C-8 position by heated glucose and oxygen radical-forming agents; Kasai H et al.; Heated glucose is mutagenic to Salmonella typhimurium TA 100 in the absence of S-9 mix . For identifying unknown mutagens in heated glucose (dry solid, 200 degrees C, 20 min), reaction with isopropylideneguanosine (IPG) was followed by isolation and characterization of the mutagen-IPG adduct . Two adducts, glyoxal-IPG and 8-hydroxy-IPG, were identified in the reaction mixture by this technique . To elucidate the mechanism of this hydroxylation reaction, we investigated the abilities of various agents to hydroxylate deoxyguanosine or guanine base in DNA . Various reducing agents, metals, asbestoses, polyphenols, aminophenols, and X-ray were effective for hydroxylation, and an oxygen radical seems to be the reactive species . For sensitive detection of 8-hydroxyguanine, a monoclonal antibody for it was prepared.

Br J Dermatol, 1986 Aug, 115 Suppl 31, 86 - 92
Cutaneous phototoxicity reactions; Lowe NJ; This paper reviews some potential mechanisms of cutaneous phototoxicity and discusses selected methods of predicting and ranking phototoxic reactions . Phototoxicity is a non-immunological reaction that is induced by the action of light on a photoactive chemical . The phototoxic chemical may be either exogenous or endogenous, and if exogenous may include topical or systemic agents . Examples of phototoxic agents include psoralens (e.g . 5-methoxypsoralen, 8-methoxypsoralen, as well as the isopsoralens) . Psoralens are used therapeutically for the treatment of different skin diseases and psoralen-like chemicals may be present in perfumes and cosmetics . Phototoxic reactions can be evaluated visually in animals . The hairless mouse has also proved useful with skin thickening as a marker of dermal oedema and the induction of polyamine biosynthetic enzymes, as well as other biochemical changes being indicative of cutaneous phototoxicity . In vitro tests of phototoxicity include the Candida albicans assay as well as bacterial mutagenicity . For example, in the latter category different psoralens vary in their ability to induce mutagenicity in Salmonella typhimurium strains, an assay which can provide rapid screening of potential phototoxicity of chemicals . For human testing, phototoxic chemicals can be delivered topically or orally, and in conjunction with appropriate ultraviolet radiation will produce phototoxic reactions which can be evaluated for intensity of response.

Environ Res, 1986 Aug, 40(2), 427 - 36
Bioavailability of 1-nitropyrene from model coal fly ash and its uptake by alveolar macrophages; Mumford JL et al.; Alveolar macrophage cultures exposed to coal fly ash vapor-coated with 1-nitropyrene were used as a model system to study the bioavailability and the uptake of a nitroaromatic hydrocarbon from coal combustion emissions . Initially, 1-nitropyrene-coated fly ash and uncoated fly ash were examined for cytotoxicity using rabbit alveolar macrophages and for mutagenicity in the Salmonella typhimurium plate incorporation assay . The results were compared to determine the effects of vapor deposition . The distribution and recovery of 1-nitropyrene from macrophage cultures treated with coated fly ash were determined by using a reverse-phase high-performance liquid chromatography-fluorescence method . 1-Nitropyrene alone was not very toxic, nor did vapor deposition of 1-nitropyrene onto coal fly ash significantly affect the toxicity of the fly ash . Most toxicity resulted from the original, uncoated fly ash particles . 1-Nitropyrene after being coated onto the particles was bioavailable in agar and aqueous culture medium . The coated fly ash showed mutagenic activity when the particles were tested directly; the uncoated fly ash did not show mutagenic activity . 1-Nitropyrene recovery from alveolar macrophage cultures exposed to the coated fly ash diminished as cell number increased . The rate of 1-nitropyrene loss was 2.7 ng/10(6) macrophages for medium and 4.1 ng/10(6) macrophages for the whole culture . The mutagenic activity recovered from these macrophage cultures also decreased with increasing cell number.

J Gen Microbiol, 1986 Aug, 132 ( Pt 8), 2079 - 85
The traT protein is able to normalize the phenotype of a plasmid-carried permeability mutation of Salmonella typhimurium; Sukupolvi S et al.; The isolation of different classes of antibiotic-supersensitive outer membrane permeability mutants of Salmonella typhimurium has been described previously (Sukupolvi et al., 1984, Journal of Bacteriology 159, 704-712) . One of these, the SS-A mutation, sensitizes the bacteria to gentian violet and to hydrophobic antibiotics . The phenotype of the SS-A mutant was restored to normal when a cloned fragment of the F plasmid, or the R plasmid R6-5, carrying the genes traS, T and D was introduced on a multicopy plasmid . The introduction of a plasmid carrying only the traT gene showed that this gene was sufficient to restore the phenotype . Only clones with functioning traT (irrespective of copy number) restored the normal antibiotic-resistant phenotype in the SS-A mutant . An incompatibility test using a donor strain which carried transposon Tn10 in the 60 MDa plasmid of S . typhimurium and a recipient in which Tn5 was placed close to the SS-A mutation indicated that the SS-A mutation was located in the 60 MDa virulence plasmid (previously called the cryptic plasmid) of S . typhimurium . The introduction of the large virulence plasmid carrying the SS-A mutant allele into wild-type S . typhimurium or Escherichia coli resulted in strains with a phenotype identical to that of the original SS-A mutant.

Mol Gen Genet, 1986 Aug, 204(2), 281 - 4
Lowered induction of genetic tandem duplications in Salmonella by the pKM101 plasmid; Pall ML et al.; Selection for 3-amino-1,2,4-triazole (AT) resistance in certain strains of Salmonella typhimurium has been previously shown to select for genetic tandem duplications of the histidine operon . We show here that agents which induce tandem duplications are less effective in such induction in the presence of the pKM101 plasmid . The presence of the plasmid also produces an increase in AT-resistance due to mechanisms other than duplication, presumably because pKM101 produces high levels of error-prone repair . We suggest that high levels of error-prone repair may cause decreases in tandem duplication induction and propose that error-prone repair and tandem duplication may be alternative cellular responses to certain DNA lesions.

J Environ Sci Health B, 1986 Aug, 21(4), 319 - 34
Screening pesticides for their ability to damage bacterial DNA; Rashid KA et al.; Twenty-six pesticides and pesticide degradation products were screened (125 micrograms - 2000 micrograms) for their ability to induce unrepairable damage to bacterial DNA . Three repair test systems were utilized in this study, the Salmonella typhimurium (TA1538/TA1978), the E . coli K-12 (Pol A1+/Pol1-) and the E . coli WP2 (WP2, WP2uvrA, WP67, CM611 and CM571) . Aldicarb (1000 micrograms), benomyl (250 micrograms), 2-aminobenzimidazole (2000 micrograms), captan (125 micrograms), fenazalor (500 micrograms), 5,6-dichloro-2-trifluoromethylbenzimidazole (NC-2983) (250 micrograms), isothymol (250 micrograms), maleic hydrazide (1000 micrograms), pentachloronitrobenzene (1000 micrograms) were DNA-damaging to one or more bacterial test systems . Isothymol and NC-2983 affected all three test systems . Chlorinated hydrocarbon insecticides, some being recognized as carcinogens, did not produce a zone of inhibition in any of the tester strains possibly due to their poor solubility and diffusion in the agar overlay . It was concluded that these tests can be performed along with bacterial reversion tests to complement each other as short-term screening tests for potential carcinogens and mutagens.

Environ Health Perspect, 1986 Aug, 67, 93 - 103
A current genotoxicity database for heterocyclic thermic food mutagens . I . Genetically relevant endpoints; Hatch FT; Cooking, heat processing, or pyrolysis of protein-rich foods induce the formation of a series of structurally related heterocyclic aromatic bases that have been found to be mutagens . The primary genetic assay utilized to detect and isolate these mutagens has been the his reversion assay in Salmonella typhimurium . The classification and nomenclature of these chemicals is revised to reflect recent advances . The findings of short-term tests for genetic injury that have been applied to these agents are presented in a systematic way . Cell-free, bacterial, mammalian cell culture, and in vivo systems are included . Major results, the mutagens tested, and key references are presented in tabular form, with text commentary . Integrated conclusions on the state of current knowledge of the genetic toxicity of thermic food mutagens are presented . Areas in need of further research are defined . Finally, an outline is presented of a suggested path leading to the determination whether normal methods of food preparation and processing constitute a human health hazard.

Environ Health Perspect, 1986 Aug, 67, 5 - 10
Past, present, and future of mutagens in cooked foods; Sugimura T; Mutation assay with Salmonella typhimurium enabled us to detect various types of mutagens in cooked foods . A series of mutagenic heterocyclic amines has been isolated and identified in broiled fish and meat and in pyrolyzates of amino acids and proteins . Feeding experiments showed these mutagens to be carcinogenic in mice and rats . The mechanism of formation and pathway of metabolic activation of these heterocyclic amines have been elucidated . Their contents in various cooked foods have been determined . The presence of mutagenic nitropyrenes (some of which were confirmed as carcinogens) in grilled chicken was also established . Roasted coffee beans also yield mutagens such as methylglyoxal . The formation of mutagen precursors, including beta-carboline derivatives and tyramine which become mutagens with nitrite treatment, was found during food processing . Oncogene activation in animal tumors induced by some of these food mutagens/carcinogens has been confirmed . The role of mutagens/carcinogens in cooked foods in human cancer development has not yet been exactly evaluated . In order to do this, more information on their carcinogenic potency, human intake, metabolism in the human body, and the effects of combined administration with other initiators, promoters and other modifying factors in food is required.

Mutat Res, 1986 Aug-Sep, 171(2-3), 99 - 104
Airplane emissions: a source of mutagenic nitrated polycyclic aromatic hydrocarbons; McCartney MA et al.; Organic solvent extracts from airplane emission particulates are mutagenic for Salmonella typhimurium strain TA98 . Using Salmonella tester strains deficient in enzymes required for the bioactivation of various nitroarenes, the mutagenicity present in these emissions was ascribed to the presence of nitrated polycyclic aromatic hydrocarbons . Based on the known aircraft particulate emission rates at U.S . airports, and using 1-nitropyrene (1-NP) and 1,8-dinitropyrene (1,8-DNP) as surrogates, it is calculated that at a minimum 7 kg 1-NP and 20 g, 1,8-DNP are emitted daily at a typical U.S . airport.

Mutat Res, 1986 Aug-Sep, 171(2-3), 63 - 70
Mutagenicity of para-substituted alpha-methylstyrene oxide derivatives with Salmonella; Rosman LB et al.; A series of 5 para-substituted alpha-methylstyrene oxide derivatives have been synthesized and together with alpha-methylstyrene oxide as well as styrene oxide have been studied as to their mutagenicity with the TA100 and TA1535 strains of Salmonella typhimurium . A multiple regression analysis model has been developed which describes the mutagenicity of the alpha-methylstyrene oxides in TA100 . An increase in van der Waals volume was the most important variable in the model with greater improvement occurring with inclusion of the Hammett values for the para substituents on the compounds . The alpha-methylstyrene oxides were less active alkylating agents with 4-(p-nitrobenzyl)pyridine than styrene oxide and with pyridine all reactivity was at the beta-epoxide carbon . However all the alpha-methylstyrene oxide derivatives, except for the bromo compound where toxicity was evident, showed mutagenicity values either greater or comparable to that of styrene oxide . These studies would indicate that reactivity at the beta-carbon should also be a factor in describing the mutagenicity of the parent styrene oxide series.

Mutat Res, 1986 Aug-Sep, 171(2-3), 157 - 63
Comparative in vivo and in vitro genotoxicity studies of airborne particle extract in mice; Krishna G et al.; The genotoxicity of an acetone extract of locally collected airborne particles was evaluated both in vitro and in vivo using the sister-chromatid exchange (SCE) assay in mice . At the highest concentration (5.36 mg/5 ml culture), the extract caused approximately a 3-fold increase in SCEs over controls in mouse bone marrow and spleen primary cells in vitro . However, the same airborne particle extract did not induce a significant increase in the SCE level over controls in vivo in mouse bone marrow and spleen cells when administered intraperitoneally or through oral gavage . This indicates that bone marrow and spleen primary cell cultures can be used in in vitro genotoxicity studies of complex mixtures, and that the genotoxicity of airborne particles detected in the in vitro system cannot always be detected in vivo with the same cell types . In addition, the same acetone extract of airborne particles caused dose-related his+ revertants in the strain TA98 of Salmonella typhimurium, both with and without S9 activation . The significant finding of this study is that the in vitro genotoxicity results of airborne particle extract may not be very meaningful in an in vivo situation.

Mutat Res, 1986 Aug-Sep, 171(2-3), 123 - 9
Hepatocyte-mediated mutagenicity of mononitrobenzo{a}pyrenes in Salmonella typhimurium strains; Hass BS et al.; The mononitro-substituted isomers of benzo{a}pyrene (B{a}P), 1-, 3- and 6-nitrobenzo{a}pyrene (NB{a}P), are environmental pollutants and are metabolized to mutagens in Salmonella by rat-liver homogenate postmitochondrial supernatant (S9) fractions . In this study, activation of these compounds to mutagens was investigated using the hepatocyte-mediated Salmonella mutagenicity assay . Hepatocytes from rats treated with Aroclor 1254 activated both 3-NB{a}P and 1-NB{a}P to mutagens, while 6-NB{a}P was not mutagenic . The positive mutagenicity responses were functions of both the chemical dose and the hepatocyte concentration . By using a nitroreductase-deficient strain (TA98NR) and a transesterificase-deficient strain (TA98/1,8-DNP6), it was verified that the direct-acting mutagenicities of 1- and 3-NB{a}P primarily were due to metabolic processes involving nitroreduction while the S9- and hepatocyte-mediated mutagenicity responses were also dependent on transesterification . When compared with the mutagenic responses produced with S9, the mutations induced by 1- and 3-NB{a}P in the presence of hepatocytes were relatively more dependent upon nitroreductase metabolism and less on transesterification . Thus, intact hepatocytes were capable of activating 1- and 3-NB{a}P to mutagenic metabolites and some of these metabolites appeared to be different from those produced by S9.

Mutat Res, 1986 Aug-Sep, 171(2-3), 105 - 13
Detection of 1-nitropyrene in yakitori (grilled chicken); Kinouchi T et al.; Pieces of raw chicken with or without a marinating sauce were grilled over a city gas flame, extracted with benzene-ethanol (4:1) by ultrasonication and fractionated into diethyl ether-soluble neutral, acidic and basic fractions . The mutagenicity of these fractions was measured with Salmonella typhimurium strains TA100, TA98, TA98NR and TA98/1,8-DNP6 in the presence and absence of a 9000 X g post-mitochondrial supernatant from Aroclor 1254-treated Sprague-Dawley rat liver (S9 mix) . The basic fraction of yakitori without the sauce was more mutagenic than the other fractions for S . typhimurium strain TA98 in the presence of S9 mix . This is probably due to the presence of amino acid or protein pyrolysates . However, when the chicken was grilled with the sauce, the basic fraction showed lower mutagenicity for strain TA98 in the presence of S9 mix than did the same fraction without the sauce . The neutral fraction of yakitori with sauce showed high mutagenicity for strain TA98 in the absence of S9 mix, but low mutagenicity for strains TA98NR and TA98/1,8-DNP6, suggesting that this fraction might contain nitropyrenes (NPs) . The neutral fraction of yakitori was analyzed by high-performance liquid chromatography (HPLC) . The neutral fraction of the chicken grilled with the sauce for 3, 5 and 7 min contained 3.8, 19 and 43 ng, respectively, of 1-NP per gram of yakitori accounting for 3.0, 2.7 and 1.3%, respectively, of the total mutagenicity.(ABSTRACT TRUNCATED AT 250 WORDS)

J Clin Microbiol, 1986 Aug, 24(2), 298 - 300
Competitive enzyme-linked immunosorbent assay for cholera-related enterotoxins in Salmonella typhimurium; Hariharan H et al.; We report a rapid competitive enzyme-linked immunosorbent assay to screen Salmonella typhimurium strains for cholera-related enterotoxin antigens . Polymyxin B extracts of bacterial cells from syncase-glucose broth cultures of 7 of 15 strains gave positive results . The specificity of the test was confirmed with known heat-labile-enterotoxin-positive and -negative Escherichia coli strains which gave significantly different values.

Proc Natl Acad Sci U S A, 1986 Aug, 83(16), 6169 - 73
In vitro reconstitution of flagellar filaments onto hooks of filamentless mutants of Salmonella typhimurium by addition of hook-associated proteins; Homma M et al.; An in vitro system for reconstituting flagellar filaments onto hooks of filamentless mutants of Salmonella typhimurium was used to investigate the role played in filament formation by the three hook-associated proteins (HAPs, products of the flaW, flaU, and flaV genes) . These proteins--FlaW, FlaU, and FlaV--are believed to be assembled in this order at the distal end of the hook . When the recipient hooks were provided by flaU mutants, whose hook tips contained FlaW only, exogenous FlaU was essential for polymerization of both exogenous and endogenous flagellin, whereas exogenous FlaV inhibited such polymerization . When the recipients were flaV-mutant hooks, whose tips contained FlaW and FlaU but not FlaV, exogenous FlaV inhibited polymerization of exogenous flagellin . FlaV also inhibited polymerization of exogenous flagellin at the tips of filament fragments . In contrast, FlaV was essential for polymerization of endogenous flagellin onto flaV-mutant hooks, and onto short filaments that had been made (in the absence of FlaV) by polymerization of exogenous flagellin on the tips of flaV-mutant hooks . These results suggest that FlaV acts not only at the tip of the hook to initiate growth of the filament, but also at the tip of the growing filament, and that FlaV is essential for polymerization of endogenous flagellin--i.e., for the normal process of filament assembly in vivo.

Mutat Res, 1986 Aug, 174(4), 259 - 63
An internal survival standard for Salmonella typhimurium forward mutation assays; Maliniack M et al.; A novel S . typhimurium forward mutation assay which avoids plating density artifacts is described . The new method uses a pair of multiply drug-resistant substrains of TM677, a bacterial strain used in previous forward mutation studies . This technique permits the measurement of cell survival following mutagen treatment by plating the culture on specially supplemented plates at the same cell concentration used to measure mutant yield . Thus this method is both technically easier and theoretically superior to our previous method.

Mutat Res, 1986 Aug, 174(4), 255 - 8
Mutagenicity of soy sauce treated with a physiologically feasible concentration of nitrite; Tahira T et al.; Soy sauce treated with nitrite was found to be more mutagenic to Escherichia coli WP2 uvrA/pKM101 than Salmonella typhimurium TA100 without S9 mix . The mutagenicity of soy sauce treated with nitrite was affected by the concentration of soy sauce in the nitrosation mixture, and a concentration of 5% resulted in the highest specific activity (revertants/ml soy sauce equivalent) . By incubating soy sauce at a concentration of 5% in a solution of 1 mM nitrite at pH 3 for 1 h at 37 degrees C, the equivalent of 1 ml of soy sauce induced 2790 revertants of E . coli WP2 uvrA/pKM101 without S9 mix.

J Med Microbiol, 1986 Aug, 22(1), 39 - 49
The nature and role of mucosal damage in relation to Salmonella typhimurium-induced fluid secretion in the rabbit ileum; Wallis TS et al.; The time course and nature of mucosal damage induced in rabbit ileal loops by two strains of Salmonella typhimurium (TML and W118) isolated from human infections was assessed by immunofluorescence microscopy and by scanning and transmission electronmicroscopy . Salmonella-induced fluid secretion occurred in the presence or absence of gross mucosal architectural damage . Neither strain caused mucosal ulceration . When damage did occur, the villi were shortened by loss of their tip regions with concomitant reforming of an intact mucosal surface . Immediately preceding the onset of fluid secretion, marked infiltration of the mucosa with polymorphonuclear leukocytes and occasional macrophages was seen . This revives an earlier suggestion that interaction between invading salmonellae and acute inflammatory cells may be an important factor in initiation of fluid secretion . Brush-border invasion by salmonellae cannot per se be the immediate cause of fluid secretion, because the latter occurred several hours after initial invasion.

J Bacteriol, 1986 Aug, 167(2), 639 - 46
crp genes of Shigella flexneri, Salmonella typhimurium, and Escherichia coli; Cossart P et al.; The complete nucleotide sequences of the Salmonella typhimurium LT2 and Shigella flexneri 2B crp genes were determined and compared with those of the Escherichia coli K-12 crp gene . The Shigella flexneri gene was almost like the E . coli crp gene, with only four silent base pair changes . The S . typhimurium and E . coli crp genes presented a higher degree of divergence in their nucleotide sequence with 77 changes, but the corresponding amino acid sequences presented only one amino acid difference . The nucleotide sequences of the crp genes diverged to the same extent as in the other genes, trp, ompA, metJ, and araC, which are structural or regulatory genes . An analysis of the amino acid divergence, however, revealed that the catabolite gene activator protein, the crp gene product, is the most conserved protein observed so far . Comparison of codon usage in S . typhimurium and E . coli for all genes sequenced in both organisms showed that their patterns were similar . Comparison of the regulatory regions of the S . typhimurium and E . coli crp genes showed that the most conserved sequences were those known to be essential for the expression of E . coli crp.

Eur J Biochem, 1986 Aug 1, 158(3), 561 - 7
Peptide uptake by Salmonella typhimurium . The periplasmic oligopeptide-binding protein; Hiles ID et al.; The uptake of most peptides, including many peptide antibiotics, by the oligopeptide permeases of Escherichia coli and Salmonella typhimurium requires the function of a specific peptide-binding protein (the OppA protein) located within the periplasm . The OppA protein is the largest and most abundant periplasmic substrate-binding protein known and has an unusually broad substrate-binding specificity . The OppA protein has been purified to homogeneity and anti-OppA antibodies have been raised . The sequence of the OppA protein has been deduced from the nucleotide sequence of the oppA gene . This protein is unrelated to any other known periplasmic substrate-binding protein, either immunologically or in its amino acid sequence . The role of this protein in peptide transport is discussed.

Carcinogenesis, 1986 Aug, 7(8), 1339 - 44
Mutagenicity of 3,4-diphenyl-5-nitrofuran analogs in Salmonella typhimurium; Ichikawa M et al.; A new series of chemicals comprising eight different 3,4-diphenyl-substituted furan analogs, namely, methyl-3,4-diphenyl-2-furoate, methyl-3,4-diphenyl-5-nitro-2-furoate, 3,4-diphenyl-5-nitro-2-furoic acid, 3,4-diphenyl-5-nitro-2-acetylfuran, 3,4-diphenyl-5-nitro-2-bromoacetylfuran, 2-amino-4-(3,4-diphenyl-5-nitro-2-furyl)thiazole, 2-acetyl-amino-4-(3,4-diphenyl-5-nitro-2-furyl)thiazole and 2-formyl-amino-4-(3,4-diphenyl-5-nitro-2-furyl)thiazole were synthesized and their mutagenic activities tested in Salmonella typhimurium . The structure--activity relationship studies revealed that for mutagenic activity the nitro group is essential and that the potency of activity is greatly altered by the nature of the substituent at the 2-position of the furan ring . The mutagenic activities of these chemicals were generally much higher in TA100 compared to TA98 . The relative order of activities for 2-substituted, 3,4-diphenyl-5-nitrofurans were COOCH3 greater than COCH2BR greater than COCH3 greater than COOH in S . typhimurium TA100 . 3,4-Diphenyl-5-nitro-2-bromoacetylfuran was equally active in nitroreductase-proficient (TA98, TA100) and in nitroreductase-deficient (TA98NR, TA100NR) strains . In contrast, the acetyl and carboxymethyl ester analogs were relatively less active in nitroreductase-deficient strains . Mutagenic activities of 3,4-diphenyl-substituted furylthiazoles in comparison with the unsubstituted analogs of N-{4-(5-nitro-2-furyl)-2-thiazolyl}-formamide, N-{4-(5-nitro-2-furyl)-2-thiazolyl}-acetamide and 2-amino-4-(5-nitro-2-furyl)thiazole revealed that the phenyl groups drastically reduced their mutagenic activities . However, the relative order of activities formylamino greater than or equal to acetylamino greater than amino were the were the same between phenyl-substituted and unsubstituted analogs.

J Bacteriol, 1986 Aug, 167(2), 616 - 22
Cloning and DNA sequence analysis of the wild-type and mutant cyclic AMP receptor protein genes from Salmonella typhimurium; Schroeder CJ et al.; The crp gene from Salmonella typhimurium, as well as two mutant adenylate cyclase regulation genes designated crpacr-3 and crpacr-4, were cloned into the EcoRI site of plasmid pUC8 . Initially cloned on 5.6-kilobase fragments isolated from EcoRI digests of chromosomal DNA, these genes were further subcloned into the BamHI-EcoRI site of plasmid pBR322 . When tested, Escherichia coli crp deletion strains harboring the clones regained their ability to pleiotropically ferment catabolite-repressible sugars . Also, the crpacr-containing strains displayed sensitivity to exogenous cyclic AMP (cAMP) when grown on eosin-methylene blue medium with xylose as the carbon source . The proteins encoded by the S . typhimurium wild-type and mutant crp genes were found to have similar molecular weights when compared with the wild-type cAMP receptor protein (CRP) from E . coli . DNA sequence analysis of the wild-type crp gene showed only a three-nucleotide difference from the E . coli sequence, suggesting little divergence of the crp gene between these organisms . The crpacr sequences, however, each contained single nucleotide changes resulting in amino acid substitutions at position 130 of the CRP . Based on the site at which these substitutions occur, the crpacr mutations are believed to affect CRP-cAMP interactions.

Biochem Biophys Res Commun, 1986 Jul 31, 138(2), 505 - 11
Frameshift mutagenesis in Salmonella typhimurium by reversible DNA intercalators: effect of a UVR B mutation; Rene B et al.; The simple reversible intercalating agents isopropyl-oxazolopyridocarbazole and 9-aminoacridine have been found to induce frameshift -1 mutations at a much lower level in Salmonella typhimurium delta uvrB TA 1537 than in the uvr+ wild type TA 1977 strain . This phenomenon can neither be explained by differential cytotoxicity of the drug nor by selective permeation and accessibility to intercalating sites to bacterial DNA . These finding indicate that the lower mutagenicity of intercalating agents in the delta uvrB strains does not result from nonspecific phenotypic modifications of parameters which control the mutagenesis . That leads to the hypothesis that in agreement with the Streisinger's model, the excision repair system could be directly involved in the appearance of frameshift mutations.

Biochemistry, 1986 Jul 29, 25(15), 4233 - 40
Beta-elimination of indole from L-tryptophan catalyzed by bacterial tryptophan synthase: a comparison between reactions catalyzed by tryptophanase and tryptophan synthase; Ahmed SA et al.; Although tryptophan synthase catalyzes a number of pyridoxal phosphate dependent beta-elimination and beta-replacement reactions that are also catalyzed by tryptophanase, a principal and puzzling difference between the two enzymes lies in the apparent inability of tryptophan synthase to catalyze beta-elimination of indole from L-tryptophan . We now demonstrate for the first time that the beta 2 subunit and the alpha 2 beta 2 complex of tryptophan synthase from Escherichia coli and from Salmonella typhimurium do catalyze a slow beta-elimination reaction with L-tryptophan to produce indole, pyruvate, and ammonia . The rate of the reaction is about 10-fold higher in the presence of the alpha subunit . The rate of indole production is increased about 4-fold when the aminoacrylate produced is converted to S-(hydroxyethyl)-L-cysteine by a coupled beta-replacement reaction with beta-mercaptoethanol . The rate of L-tryptophan cleavage is also increased when the indole produced is removed by extraction with toluene or by condensation with D-glyceraldehyde 3-phosphate to form indole-3-glycerol phosphate in a reaction catalyzed by the alpha subunit of tryptophan synthase . The amount of L-tryptophan cleavage is greatest in the presence of both beta-mercaptoethanol and D-glyceraldehyde 3-phosphate, which cause the removal of both products of cleavage . The cleavage reaction is not due to contaminating tryptophanase since the activity is not inhibited by (3R)-2,3-dihydro-L-tryptophan, a specific inhibitor of tryptophanase, but is inhibited by (3S)-2,3-dihydro-L-tryptophan, a specific inhibitor of tryptophan synthase . The cleavage reaction is also inhibited by D-tryptophan, the product of a slow racemization reaction.(ABSTRACT TRUNCATED AT 250 WORDS)

Biochem Pharmacol, 1986 Jul 15, 35(14), 2313 - 22
Inhibition of the mutagenicity and metabolism of 6-methyl-benzo{a}pyrene and 6-hydroxymethyl-benzo{a}pyrene; Bayless JH et al.; Previously reported inhibitors of benzo{a}pyrene (BaP) mutagenicity in Salmonella typhimurium strain TA98 were tested for their effectiveness against the mutagenicity of 6-methyl-benzo{a}pyrene (6-CH3-BaP), 6-hydroxymethyl-benzo{a}pyrene (6-CH2OH-BaP) and 6-acetoxymethyl-benzo{a}pyrene (6-CH3COOCH2-BaP) . Dose-response curves obtained for phenothiazine (PTH), 2-chlorophenothiazine (2Cl-PTH), phenylisothiocyanate (PHN), phenethylisothiocyanate (PNE), trans-retinol (TR) and disulfiram (TETD) showed a variety of degrees of inhibition of mutagenicity . Additionally, glutathione (GSH) was found to inhibit the mutagenicity of 6-CH3COOCH2-BaP, and the mutagenicity of 6-CH2OH-BaP was enhanced by the addition of supplemental ATP, Na2SO4 and EDTA . Only 2Cl-PTH was equally as good an inhibitor of 6-CH3-BaP and BaP, reducing revertant colonies to less than 50% of control at 10 X BaP concentration . To probe the mechanism of inhibition, the effect of 2Cl-PTH on the binding of BaP and the 6-substituted benzo{a}pyrenes to cytochrome P-450 was investigated by difference spectroscopy . Also, the effect of 2Cl-PTH on the subsequent metabolism of 6-CH3-BaP and 6-CH2OH-BaP was investigated by rapid scan difference spectroscopy and high-performance liquid chromatographic separation of products . The results are consistent with a major mechanism of inhibition for 2Cl-PTH involving a competition for the cytochrome P-450 binding site.

J Comp Pathol, 1986 Jul, 96(4), 379 - 86
An in vivo and in vitro study of selenium deficiency and infection in rats; Boyne R et al.; Selenium deficiency in rats impairs the ability of neutrophils and peritoneal macrophages to kill Candida albicans organisms in vitro . In contrast, killing of Salmonella typhimurium and Staphylococcus aureus organisms is unaffected by the deficiency . Survival of rats after intraperitoneal injection of 8 X 10(7) S . aureus organisms was not affected by Se deficiency, but a 5-fold increase in the dose (4 X 10(8) S . aureus organisms) led to a significantly greater mortality in the Se deficient rats.

Infect Immun, 1986 Jul, 53(1), 26 - 31
Yersinia enterocolitica infection in resistant and susceptible strains of mice; Hancock GE et al.; We investigated natural resistance in mice to Yersinia enterocolitica, an enteric bacterial pathogen of humans, with a view to determine host genetic factors that are important in resistance . Most mouse strains studied (C3H/HeN, BALB/c, BALB.B, DBA/2, A, Swiss, and SWR) were highly susceptible to infection (50% lethal dose {LD50}, 2 X 10(2) to 6 X 10(2) Y . enterocolitica administered intravenously {i.v.}) . In contrast, C57BL/6 mice were highly resistant (LD50, 2 X 10(5) Y . enterocolitica administered i.v.) . Resistance to i.v . Yersinia infection did not appear to be related to the Ity locus (which codes for resistance to Salmonella typhimurium and other pathogens) because Ityr mice (C3H/HeN, DBA/2, A, and SWR) were more susceptible to Y . enterocolitica than were Itys (C57BL/6) mice . In addition, because BALB.B mice (congenic to C57BL/6 mice at the H-2 locus) were susceptible, resistance was probably not H-2 linked . BALB/c X C57BL/6 F1 mice were intermediate in their resistance to Y . enterocolitica infection (LD50, 3 X 10(4) organisms administered i.v.), suggesting that resistance to Y . enterocolitica depends on a gene dosage affect or a resistance gene(s) interaction between susceptible and resistant parents . Further studies with C57BL/6 and BALB/c mice as prototype resistant and susceptible strains were undertaken . A time course study of Y . enterocolitica growth in various organs following i.v . infection revealed no strain difference in bacterial growth during the first 48 h of infection . Thereafter, however, C57BL/6 mice were capable of restricting Y . enterocolitica growth in all tissues (liver, lung, spleen, kidneys), whereas extensive bacterial proliferation occurred in BALB/c mice tissues . BALB/c mice were also more susceptible to oral Y . enterocolitica infection than were C57BL/6 mice, demonstrating increased mortality and greater numbers of bacteria in the Peyer's patches . Finally, whereas thymus-bearing C57BL/6 X BALB/c F1 mice were resistant to infection, athymic (nude) C57BL/6 X BALB/c F1 mice were susceptible . These studies provide a model to investigate natural immunity to enteric pathogens at mucosal surfaces, as well as provide the basis for clarifying the role of host genotype in Y . enterocolitica resistance.

J Med Chem, 1986 Jul, 29(7), 1319 - 21
Isolation, synthesis, and antitumor evaluation of spirohydantoin aziridine, a mutagenic metabolite of spirohydantoin mustard; Struck RF et al.; Spirohydantoin mustard (SHM), a central nervous system directed nitrogen mustard with anticancer activity, was metabolized in the presence of mouse liver postmitochondrial supernatant (9000g fraction) to a nonpolar alkylating metabolite . The metabolite was isolated by thin-layer chromatography of chloroform or ethyl acetate extracts of incubation mixtures, and its structure was established by mass spectral analysis, synthesis, and cochromatography . The metabolite, spirohydantoin aziridine, was mutagenic for Salmonella typhimurium TA1535 in the Ames assay but inactive as an antitumor agent against P388 leukemia in vivo.

J Appl Bacteriol, 1986 Jul, 61(1), 51 - 6
Laboratory studies on salmonella-contaminated cheese involved in a major outbreak of gastroenteritis; Ratnam S et al.; A major outbreak of gastroenteritis was traced to Cheddar cheese contaminated with Salmonella typhimurium . There were no significant differences in pH values of the contaminated (mean pH 5.31) and non-contaminated (mean pH 5.39) cheese . The isolation rates of Salm . typhimurium were about the same when cheese samples were homogenized in lactose broth, lactose broth containing 1% Tween 80, or in aqueous 2% sodium citrate . Salmonella typhimurium was isolated regardless of preenrichment in lactose broth, but required selective enrichment in selenite cystine or tetrathionate brilliant green broth . There were no marked differences in the isolation rates obtained with different selective enrichment media, or after incubation at 36 degrees and 43 degrees C for 24 or 48 h . Contaminated samples of cheese failed to yield Salm . typhimurium consistently despite large and multiple samplings; samples from the interior of cheese blocks yielded positive results more frequently than the samples from the exterior . The number of Salm . typhimurium in factory sealed blocks as well as in samples obtained from the homes of known cases of salmonellosis was found to range from less than 3/100 g to 9/100 g of cheese . The infective dose of Salm . typhimurium in contaminated cheese was probably no greater than 10(4) organisms, and a rapid decline in numbers of Salm . typhimurium must have occurred subsequent to the outbreak.

Ann Inst Pasteur Immunol, 1986 Jul-Aug, 137D(1), 93 - 107
Increased phagocytic activity in mice treated by a mouse granuloma protein; Fontan E et al.; Intravenous injection of a protein extracted from a talc-induced granuloma (MGP) enhanced the blood clearance of a highly virulent strain of Salmonella typhimurium . This protein was able to enhance mouse resistance to systemic infection with Listeria monocytogenes when injected one or two days prior to infection . Furthermore, since MGP-treated athymic mice were also protected against Listeria infection, mature T cells were most likely not involved in this enhanced resistance . These findings suggest that this increased resistance to infection correlates with an activation of liver and spleen macrophages . This protective effect of MGP was not due to possible endotoxin contamination of the preparation, as the MGP activity was destroyed by heating.

Immunology, 1986 Jul, 58(3), 379 - 87
Functional characteristics of the veiled cells in afferent lymph from the rat intestine; Mayrhofer G et al.; Non-lymphoid veiled cells (VC) in the thoracic duct lymph from mesenteric lymphadenectomized rats have been studied by light microscopy, enzyme histochemistry and scanning electron microscopy . These cells arise in the afferent lymph from the intestine . They have been semi-purified and examined for expression of Ia antigens using an indirect immunoperoxidase technique and monoclonal antibodies . Accessory cell function necessary for mitogen-induced blastogenesis in the thoracic duct lymph from these animals has been correlated with the presence of VC by depletion and reconstitution experiments . Similar results were obtained with lymphocyte suspensions from other rat lymphoid organs and they are contrasted with those from studies on mouse lymphoid cells . Antigen presentation in a secondary in vitro lymphoproliferative assay was also depleted from immunized lymph node cells by removal of endogenous VC and can be reconstituted in a dose-dependent fashion with antigen-pulsed VC from afferent intestinal lymph . In contrast, reconstitution of both mitogen-induced blastogenesis and antigen-induced lymphoproliferation with peritoneal exudate cells was poor, while at high multiplicities of added macrophages, such cells were inhibitory . Afferent intestinal lymph VC were found to transport bacteria and bacterial antigen in rats infected with Salmonella typhimurium . The results are discussed in relation to the lineage of the VC in intestinal afferent lymph, their function as accessory cells and their possible physiological role in transporting antigens from the gut to its regional lymph nodes.

Fundam Appl Toxicol, 1986 Jul, 7(1), 1 - 16
Regulatory implications of Ames' mutagenicity assay using Salmonella typhimurium; Jackson BA et al.; Interpretive difficulties can be expected when molecular biology and modern genetics are applied to the safety evaluation of chemicals . Experience, in a regulatory setting, with evaluating the results of short term tests, such as Ames' mutagenicity assay using Salmonella typhimurium (Ames' assay), shows that the traditional toxicological paradigm for interpreting and evaluating the results of such tests is less than adequate . The considerable importance of a negative test outcome to the public health as well as to the course of the commercial development of a potentially useful chemical places special demands on both the investigator and the regulatory reviewer for an understanding of Ames' assay . The adequate design, conduct, interpretation, and evaluation of the outcomes of this assay require a knowledge of the chemical properties of the test agent, an understanding of the scientific basis of the test, and an appreciation of the extent to which modifications of the assay can alter the outcome . The investigator and the regulatory reviewer use the same considerations to determine the adequacy of the test design and of the test results . However, a fundamental difference exists between how they interpret results and how they view the outcome . Results from a study comparing activation systems from food animal and laboratory animal sources are used to illustrate the complexity of using safety data from a genetic test . A framework is developed to suggest how to accommodate the points of view of the investigator and the regulatory reviewer in evaluating these data.

Proc Natl Acad Sci U S A, 1986 Jul, 83(14), 5189 - 93
Mutants of Salmonella typhimurium that cannot survive within the macrophage are avirulent; Fields PI et al.; Salmonella typhimurium is a facultative intracellular pathogen capable of surviving within phagocytic cells of the reticuloendothelial system . To identify the genes important for intracellular survival, 9516 independent Tn10 insertional mutations were isolated in a virulent strain of S . typhimurium . By using an in vitro assay for survival within macrophages, 83 Tn10 mutants have been identified that have a diminished capacity for intracellular survival (designated MS or macrophage survival mutants) . All of the MS mutants are less virulent than the parent strain in vivo, demonstrating that, for Salmonella, survival within the macrophage is essential for virulence . Thirty-seven of the MS mutants have been characterized as to their phenotype, including several mutations that confer sensitivity to specific microbiocidal mechanisms of the macrophage.

Mutat Res, 1986 Jul, 174(3), 169 - 73
Genetic activity of 2-aminofluorene in the salmonella/erythrocyte mutagenicity assay; Cantelli-Forti G et al.; In a previous study, we demonstrated the activation of cyclophosphamide by mouse erythrocytes in a yeast test using the D7 strain of Saccharomyces cerevisiae . The present study provides further information on the ability of washed red blood cells from mice to activate 2-aminofluorene (2-AF) detected as an increase in mutation frequency of the tester strain, TA1538 (frameshift mutation) of Salmonella typhimurium . The 2-AF was tested at different concentrations (1-8 micrograms/plate) using both the liquid-suspension test and the agar-plate test . For comparison, the bioactivation of 2-AF by the hepatic postmitochondrial supernatant (S9 fraction) from Aroclor-1254-induced rats was studied . 2-AF was only found to be clearly mutagenic in the agar-plate test with both activation systems . The genetic response obtained with the erythrocytes appeared to be related to the number of cells/plate . At the lowest dose, slight differences are observed when genotoxic effects were compared to those with the S9 fraction.

J Bacteriol, 1986 Jul, 167(1), 420 - 2
Mutant of Salmonella typhimurium LT2 deficient in DNA adenine methylation; Ritchie LJ et al.; A mutant of Salmonella typhimurium LT2 deficient in methylation of the adenine residues in the sequence 5'-GATC-3' was isolated . The mutation (dam-1) was linked to the cysG locus, and the properties of the mutant were similar to those of Escherichia coli dam mutants . Reversion of the hisC3076 frameshift marker by 9-aminoacridine was substantially enhanced by the dam-1 mutation, implying a direct role for adenine methylation in the prevention of frameshift mutation induction.

Carcinogenesis, 1986 Jul, 7(7), 1239 - 41
Synthesis and mutagenicity of 3,3'-dihalogenated benzidines; Savard S et al.; 3,3'-Difluorobenzidine (F2Bz), and 3,3'-dibromobenzidine (Br2Bz) were synthesized and compared with 3,3'-dichlorobenzidine (Cl2Bz) for ability to revert Salmonella typhimurium . The relative mutagenicities in all systems are Cl2Bz approximately equal to Br2Bz greater than F2Bz greater than Bz . F2Bz, Cl2Bz, and Br2Bz are direct-acting mutagens towards S . typhimurium strain TA98 . The acetylase-deficient derivative TA98/1,8-DNP6 displays no resistance to induction of mutagenesis by these compounds, in the absence of mammalian activation . With addition of hamster hepatic S-9 activation the mutagenicity of these compounds increases greatly . TA98/1,8-DNP6 shows some resistance to this mutagenicity . Multiple mechanisms must exist for the genotoxicity of 3,3'-dihalogenated benzidines.

Mutagenesis, 1986 Jul, 1(4), 267 - 73
Conditions for the optimal use of the L-arabinose-resistance mutagenesis test with Salmonella typhimurium; Hera C et al.; Different conditions of mutagenesis have been compared in order to optimize the use of the L-arabinose resistance test with Salmonella typhimurium . The mutagenesis protocols compared were the plate-incorporation, the pre-incubation and the liquid tests . Fourteen chemicals were used in the comparison: six direct-acting mutagens and eight pre-mutagens . Five concentrations of S9 (3, 7.5, 10, 15 and 33% v/v) were compared in the liquid test with pre-mutagens, and three densities of bacteria (ranging from 10(8) to 10(6) cells) were used in the comparison between the plate-incorporation and the pre-incubation mutagenesis test . In general, the liquid test proved the most sensitive mutagenesis protocol . When carrying out this test in a mass screening of mutagens, we propose to select the L-arabinose-resistant mutants in plates supplemented with 0.5 mg of D-glucose, and to express the mutagenic response as the absolute number of induced mutants . The plate-incorporation and the pre-incubation mutagenesis protocols could be considered as alternative procedures in the case of previous negative results with the liquid test . Two recommendations can be finally made in order to avoid false negative results: (a) a large population of bacteria (ranging from 10(8) to 10(7) cells) must be exposed to the mutagens in both the plate-incorporation and the pre-incubation mutagenesis tests, and (b) ideally, several S9 concentrations (ranging from 3 to 30% v/v) would be employed for testing in liquid samples of unknown mutagenicity.

Mutagenesis, 1986 Jul, 1(4), 275 - 82
Computer-automated prediction of the mutagenicity of benzidine, 4,4"-diaminoterphenyl, 4-dimethylaminoazobenzene and 4-cyanodimethylaniline: comparison with the results of the Second UKEMS Collaborative Study; Rosenkranz HS et al.; There was agreement between the experimental results, obtained in the course of the Second UKEMS Collaborative Study, for the mutagenicity in Salmonella typhimurium of benzidine, 4,4"-diaminoterphenyl, 4-dimethylaminoazobenzene and 4-cyanodimethylaniline and the mutagenicity predicted by CASE (Computer Automated Structure Evaluation), a recently developed artificial intelligence system.

Rev Infect Dis, 1986 Jul-Aug, 8 Suppl 4, S409 - 19
Use of a new, low-pH immunoglobulin G preparation during episodes of bacteremia in the rat; Emerson TE Jr et al.; A rapidly expanding role for immunoglobulin G preparations in conditions other than the classical immunodeficiency syndromes is evident . This relatively new concept of treatment with polyclonal antibody has been tested in the rat with severe Salmonella typhimurium bacteremia with use of a newly developed, native immunoglobulin G preparation for intravenous use (IGIV pH 4.25) . IGIV pH 4.25 increased survival time and decreased absolute mortality, prevented hypotension and acidosis, and ameliorated or prevented changes in variables indicative of organ damage during S . typhimurium bacteremia in the rat . Intravenous infusion of IGIV pH 4.25 at high rates did not cause further deterioration in the arterial blood pH in the acid-base-compromised rat and hence should not cause clinically significant decreases in pH in patients with compromised acid-base regulating systems.

Infect Immun, 1986 Jul, 53(1), 116 - 23
Factors responsible for increased susceptibility of mice to intestinal colonization after treatment with streptomycin; Que JU et al.; Streptomycin sulfate (5 mg/ml) was added to the drinking water of Swiss white mice . After treatment for 1 week, the mice were challenged orogastrically with 10(8) Pseudomonas aeruginosa cells . The organism failed to multiply in the intestinal tract of either treated or untreated animals, but could be recovered from contents and tissues after 48 h . In a previous study, Salmonella typhimurium was shown to multiply in the intestines of streptomycin-treated but not untreated mice when 10(3) organisms were used as inoculum . Streptomycin administration had little effect on Eh, protein or carbohydrate concentrations of cecal contents, or intestinal motility . However, it caused a statistically significant increase in water content and pH of contents and a decrease in the concentrations of acetic, propionic, butyric, and valeric acids . S . typhimurium multiplied in pooled cecal contents obtained from both streptomycin-treated and untreated animals, but its multiplication rate and total populations were significantly greater in contents from treated animals . P . aeruginosa did not multiply in contents from either treated or untreated mice . Similar results were obtained when the organisms were inoculated into nutrient broth adjusted to simulate the pH levels and volatile fatty acid (VFA) concentrations in cecal contents of treated and untreated mice . The addition of brain heart infusion broth to cecal contents from untreated animals, in concentrations that support multiplication of S . typhimurium and P . aeruginosa, did not reverse inhibition . The addition of VFA to cecal contents from treated animals to equal the concentration in cecal contents from untreated animals caused inhibition of a magnitude observed in cecal contents from untreated animals . The results indicate that VFA operating at the pH level of cecal contents of conventional mice inhibit the multiplication of both S . typhimurium and P . aeruginosa and restrict colonization of the intestine by these organisms . The decrease in VFA concentrations that occurs as a result of streptomycin administration adequately explains the increased susceptibility of treated mice to colonization with S . typhimurium . It does not explain the increased susceptibility of treated mice to P . aeruginosa colonization, however.

Genetics, 1986 Jul, 113(3), 499 - 515
Interaction of DNA polymerase III gamma and beta subunits in vivo in Salmonella typhimurium; Engstrom J et al.; We show that temperature-sensitive mutations in dnaZ, the gene for the gamma subunit of DNA polymerase III holoenzyme, can be suppressed by mutations in the dnaN gene, which encodes the beta subunit . These results support a direct physical interaction of these two subunits during polymerase assembly or function . The suppressor phenotype is also sensitive to modulation by the dnaA genotype . Since dnaA is organized in an operon with dnaN, and dnaA is a regulatory gene of this operon, we propose that the dnaA effect on suppression can best be explained by modulation of suppressor dnaN levels.

Mutat Res, 1986 Jul, 166(1), 29 - 37
Enhancement of UV survival, UV- and MMS-mutability, precise excision of Tn10 and complementation of umuC by plasmids of different incompatibility groups; Brunner DP et al.; 29 conjugative resistance and colicin plasmids from 19 different incompatibility (Inc) groups were examined for their ability to enhance post-ultraviolet (UV) survival and UV- and methyl methanesulfonate(MMS)-induced mutability in Salmonella typhimurium LT2 strains . 14 Muc+ plasmids enhanced each of the survival and mutation-related properties tested, while 14 Muc- plasmids showed no enhancing effects in any tests . One Muc+ plasmid, pRG1251 (IncH1), enhanced post-UV survival and each of the mutation-related properties tested, except MMS-induced mutagenesis . Two further noteworthy plasmids, R391 (IncJ) and R394 (IncT), produced apparent strain-dependent effects in S . typhimurium which differed from those reported to have been found in Escherichia coli . Plasmid R391 enhanced post-UV survival in S . typhimurium, in contrast to its UV-sensitizing effects in E . coli . In both hosts plasmid R391 enhanced UV- and MMS-induced mutagenesis . Plasmid R394 had no enhancing effects on UV survival or UV- and MMS-induced mutagenesis in S . typhimurium, in contrast to its reported enhancement of MMS-induced mutagenesis in E . coli . Conjugal transfer of R394 to E . coli strain AB1157 and assays of mutagenesis-related traits supported results observed in S . typhimurium . Muc+ plasmids were found to enhance the frequency of precise excision of the transposon Tn10 when inserted within hisG or trpA in S . typhimurium strains . Precise excision could be further enhanced in S . typhimurium by UV-irradiation . Analysis of Tn10 mutants with altered IS10 ends indicated that intact inverted repeats at the ends of Tn10 were required for efficient enhancement of precise excision.

J Infect Dis, 1986 Jul, 154(1), 156 - 62
Cloned, random chromosomal sequences as probes to identify Salmonella species; Tompkins LS et al.; We have developed and evaluated a new technique--chromosomal probe fingerprinting--to differentiate between strains of Salmonella species by using sequences of cloned chromosomal DNA as probes to highlight restriction site heterogeneity . Chromosomal probe fingerprint patterns were compared with other strain-typing methods and epidemiological data . Seventeen isolates of Salmonella typhimurium recovered from 11 outbreaks had six unique chromosomal probe fingerprint patterns . Most strains of Salmonella dublin, including some that had identical plasmid profiles and restriction endonuclease analysis patterns, could be distinguished by this method . On the other hand, eight of nine isolates of Salmonella enteritidis had a common chromosomal probe fingerprint pattern, although there were differences in plasmid profiles and the isolates had been collected over a lengthy time interval from widely disparate geographic locations . These results suggest clonal dissemination of some Salmonella serovars.

J Bacteriol, 1986 Jul, 167(1), 73 - 6
Hydroxamate production by Aquaspirillum magnetotacticum; Paoletti LC et al.; Spent culture fluids from Aquaspirillum magnetotacticum MS-1 grown at high (20 microM) but not low (5 microM) iron concentration contained material yielding a positive hydroxamate test . Cells possessed six major outer membrane proteins . Three outer membrane proteins ranging from 72,000 to 85,000 daltons were coordinately produced at iron concentrations conducive to hydroxamate production . A 55,000-dalton iron-repressible outer membrane protein was also present in strain MS-1 cultured at low but not high ferric quinate concentration . Culture fluids from strain MS-1 which were hydroxamate positive augmented growth of a Salmonella typhimurium siderophore-deficient (enb-7) mutant in low-iron medium, suggesting a role of hydroxamate in uptake of iron by the cell.

Mutagenesis, 1986 Jul, 1(4), 283 - 6
Enhancement of frameshift mutagenesis in Salmonella typhimurium derivatives of hisC3076 by 5-azacytidine and other agents; Podger DM et al.; The yield of frameshift revertants of Salmonella typhimurium strain hisC3076 on plates containing the mutagen 9-aminoacridine (9AA) is enhanced by the addition to the selection medium of a number of chemical agents . These include 5-azacytidine (5-azaC), naladixic acid, ethyl methanesulphonate; pre-treatment of cells with u.v . light or gamma-radiation is also effective . With the exception of u.v . which is detected as a poor mutagen in strain hisC3076, all other enhancing agents are not usually detected as mutagens in this strain . The observed synergism between 9AA and 5-azaC in recA and uvrB derivatives of hisC3076 eliminates the possibility that recA-dependent repair or excision repair is necessary . However a lack of synergism in a uvrD derivative suggests that helicase II is involved . It is suggested that the presence of 9AA in the plating medium enables the synergistic agents to be detected as mutagens.

J Appl Bacteriol, 1986 Jul, 61(1), 11 - 8
Mechanisms of triple stress-mediated damage in stationary phase cells of Salmonella typhimurium exposed to succinate-acidified hypochlorite system at 5 degrees C; Obafemi A et al.; Exposure for 20 min of stationary phase cells of Salmonella typhimurium to a combined triple stress system (TSS) treatment comprising hypochlorite derived 5 ppm free available chlorine in solution acidified with 1% succinate (pH 2.5) and at a chill shock temperature of 5 degrees C resulted in symptoms of injury . Cells became sensitive to 40 micrograms/ml lysozyme, 50 micrograms/ml actinomycin D and 100 micrograms/ml ribonuclease B, to which control cells were resistant . Metabolic injury was indicated by reduction in colony forming ability of stressed cells on minimal salts glucose agar M9 medium . There was no detectable leakage loss of 260-280 nm-absorbing materials . This was also confirmed by assay of the cellular RNA material components . Loss of alkaline phosphatase activity was observed in the stressed cells . The intensity of induced cellular damage as measured by lysozyme sensitivity was greatest in the cells exposed to the complete TSS, followed by those stressed in 1% succinate at 5 degrees C, then 5 ppm chlorine at 5 degrees C and the singular chill shock stress at 5 degrees C, respectively . The magnitudes of cellular damage, however, were suggestive of synergistic interactions among the component stress factors of the TSS . The findings obtained indicated impairment of the structural integrity and functional capabilities of the permeability barriers and the inactivation of certain periplasmic enzymes . The resultant cumulative cellular damage from the TSS exposure may therefore enhance greater sensitivity of treated cells to subsequent stress factors.

Biochemistry, 1986 Jun 3, 25(11), 3261 - 7
Biosynthetic alanine racemase of Salmonella typhimurium: purification and characterization of the enzyme encoded by the alr gene; Esaki N et al.; An alanine racemase, encoded by the alr (dal) gene and believed to be the biosynthetic source of D-alanine for cell wall formation, was purified to homogeneity from an overproducing strain of Salmonella typhimurium (dadB), and the enzymological properties of this enzyme were compared with those of the dadB alanine racemase that functions in the catabolism of L-alanine {Wasserman, S . A., Daub, E., Grisafi, P., Botstein, D., & Walsh, C . T . (1984) Biochemistry 23, 5182} . The alr-encoded enzyme has a monomeric structure with a molecular weight of about 40 000 . One mole of pyridoxal 5'-phosphate is bound per mole of enzyme, which is essential for catalytic activity of the enzyme . After the internal Schiff base with pyridoxal 5'-phosphate was reduced with NaB3H4, followed by carboxamidomethylation and tryptic digestion of the enzyme, the amino acid sequence of the pyridoxal 5'-phosphate binding peptide was determined . The sequence of 10 amino acid residues around the lysine residue, to which pyridoxal 5'-phosphate is bound, was identical with that of the dadB racemase . No homology was found in the amino-terminal amino acid sequence between the two enzymes . The enzyme was inactivated with D- and L-beta-fluoroalanine, D- and L-beta-chloroalanine, and D-O-acetylserine in a mechanism-based fashion with a common partition ratio of about 150 . The enzyme was labeled with an equimolar amount of {14C}-D-beta-chloroalanine . The inactivator-pyridoxal 5'-phosphate adduct was isolated and shown to be the same structure formed in the dadB racemase inactivation {Roise, D., Soda, K., Yagi, T., & Walsh, C . (1984) Biochemistry 23, 5195}.

Biochemistry, 1986 Jun 3, 25(11), 3255 - 60
Biosynthetic alr alanine racemase from Salmonella typhimurium: DNA and protein sequence determination; Galakatos NG et al.; The nucleotide sequence of the alr gene encoding the biosynthetic alanine racemase in Salmonella typhimurium is reported . The sequence was determined by the dideoxy chain termination method of Sanger mostly from recombinants derived from shotgun and specific subcloning of a 2.6-kilobase region containing the alr gene . The final bridging of nonoverlapping contiguous sequences was accomplished with the use of synthetic site-specific primers . The alr gene was found to be 1077 base pairs in length encoding a protein of 359 amino acid residues . Comparison of alr with the dadB gene encoding the catabolic alanine racemase in S . typhimurium revealed almost identical size (1077 vs . 1068 base pairs) and 52% sequence identity . The respective gene products displayed 43% homology, which includes a decapeptide bearing the pyridoxal 5'-phosphate binding site.

Biochemistry, 1986 Jun 3, 25(11), 3118 - 24
Identification of three sites of proteolytic cleavage in the hinge region between the two domains of the beta 2 subunit of tryptophan synthase of Escherichia coli or Salmonella typhimurium; Ahmed SA et al.; The beta 2 subunit of tryptophan synthase is composed of two independently folding domains connected by a hinge segment of the polypeptide that is particularly susceptible to limited proteolysis by trypsin {Hogberg-Raibaud, A., & Goldberg, M . (1977) Biochemistry 16, 4014-4019} . Since tryptic cleavage in the hinge region inactivates the beta 2 subunit, the spatial relationship between the two domains is important for enzyme activity . However, it was not previously known whether inactivation results from cleavage of the chain or from the loss of internal fragment(s) subsequent to cleavage at two or more sites . We now report comparative studies of limited proteolysis by three proteinases: trypsin and endoproteinases Lys-C and Arg-C . Our key finding that endoproteinase Arg-C inactivates the beta 2 subunit by cleavage at a single site (Arg-275) demonstrates the important role of the hinge peptide for enzymatic activity . We have also identified the sites of cleavage and the time course of proteolysis by trypsin at Arg-275, Lys-283, and Lys-272 and by endoproteinase Lys-C at Lys-283 and Lys-272 . Sodium dodecyl sulfate gel electrophoresis, Edman degradation, and carboxypeptidases B and Y have been used to identify the several fragments and peptides produced . Our finding that the beta 2 subunit and F1 fragments have a heterogeneous amino terminus (Met-1 or Thr-2) indicates that the amino-terminal methionine is incompletely removed during posttranslational modification . Our results show that Edman degradation can be effectively used with a protein of known sequence to analyze proteolytic digests that have at least four different amino-terminal sequences.(ABSTRACT TRUNCATED AT 250 WORDS)

Eur J Biochem, 1986 Jun 2, 157(2), 335 - 42
Cloning and structural characterization of the Salmonella typhimurium pyrC gene encoding dihydroorotase; Neuhard J et al.; The pyrC gene of Salmonella typhimurium, encoding the third enzyme of pyrimidine nucleotide biosynthesis, dihydroorotase, has been cloned into the multicopy plasmid pBR322 . The recombinant plasmid, pJRC1, promoted the synthesis of 20-30-fold elevated levels of dihydroorotase . The expression of pyrC was regulated to the same extent by pyrimidines whether present on the multicopy plasmid or in single copy on the chromosome . A comparison of the polypeptides encoded by pyrC-complementing and non-complementing plasmids showed the gene product to have a molecular mass of approximately 37 kDa . The nucleotide sequence of the gene and 400 base pairs upstream from the coding region was determined . An open-reading frame, encoding a protein with a calculated molecular mass of 38 500 Da, was deduced to be the coding region for pyrC . S1 nuclease mapping indicated that transcription of pyrC is initiated 40 base pairs upstream from the translational start . Subcloning of a 184-base-pair DNA fragment, which included 118 base pairs upstream from the transcriptional start, and the first eight codons of the pyrC structural gene, into a galK expression vector, established that the pyrC promoter and regulatory region are harbored on this fragment . The leader region does not show any features resembling the attenuators found in front of the coding regions of pyrB and pyrE; however, it contains a region of dyad symmetry, which may allow the leader transcript to form a stable hairpin . The possible significance of this putative hairpin formation in the regulation of pyrC expression is discussed.

Carcinogenesis, 1986 Jun, 7(6), 959 - 63
Anti-mutagenesis and anti-promotion by apigenin, robinetin and indole-3-carbinol; Birt DF et al.; We assessed the anti-mutagenic and anti-promotion properties of two flavones, apigenin and robinetin, and of indole-3-carbinol, because these compounds have been reported in vegetables, the consumption of which has been associated with reduced rates of cancer . However, the active components of these foods and their effects on carcinogenesis have not been established . Anti-mutagenicity was determined in the Salmonella typhimurium assay by measuring the effects of the test compounds on bacterial mutagenesis induced by methyl-nitrosourea (MNU), methyl-n-nitro-N-nitrosoguanidine (MNNG), benzo{a}pyrene (BaP) or 2-aminoanthracene (2-AA) . Inclusion of apigenin resulted in a 62% and a 43% inhibition of mutagenicity with 13 nmol of 2-AA and 30 nmol BaP respectively . Robinetin caused an 87% inhibition of mutagenicity by 2-AA, but indole-3-carbinol had little or no effect on the mutagenicity of any of the compounds . None of the three compounds inhibited mutagenesis by MNU or MNNG and none were mutagenic or toxic when tested in the absence of mutagenic compounds at doses up to 20 micrograms/plate . Anti-promotion properties were assessed by measuring the effects of apigenin, robinetin and indole-3-carbinol on induction of ornithine decarboxylase activity (ODC) in mouse epidermis by 17 nmol 12-O-tetradecanoyl phorbol-13-acetate (TPA) . Pretreatment of the skin half an hour before TPA with apigenin, robinetin, butylated hydroxyanisole, 13-cis-retinoic acid (all at 50 mumol) or di-fluoromethylornithine (1.6 mumol) inhibited ODC induction at 6 h after TPA by 67-80% . Pretreatment with 50 mumol indole-3-carbinol caused a 78% elevation in the TPA induction at this time . Dose response measurements were conducted with apigenin, indole-3-carbinol and robinetin . Inhibition by 30-90% of TPA-induced ODC was observed at 6 h after TPA in mice pretreated with 12.5-100 mumol apigenin . Pretreatment with 37.5 or 50 mumol indole-3-carbinol or 0.5, 12.5 or 25 mumol robinetin resulted in elevated induction of epidermal ODC by TPA at 6 h after TPA . However, treatment with 50 or 100 mumol robinetin diminished ODC induction at 6 h after TPA . Treatment with 100 mumol apigenin or 50 or 100 mumol indole-3-carbinol in non-TPA-treated mouse skin caused elevations in epidermal ODC . In comparing the time course of ODC induction, indole-3-carbinol (50 mumol) pretreatment shifted the induction of epidermal ODC to earlier times, in addition to elevating ODC induction by TPA.(ABSTRACT TRUNCATED AT 400 WORDS)

Eur J Epidemiol, 1986 Jun, 2(2), 99 - 103
Metastatic focal infections due to multiresistant Salmonella typhimurium in children: a 34 month experience in Rwanda; Lepage P et al.; Nineteen out of 139 children with severe systemic disease due to multiresistant Salmonella typhimurium observed during a 34-month period in an in-patient department in Rwanda had focal metastatic infections . More than 80% of the invasive Salmonella infections were acquired in the hospital . Focal metastatic infections occurred after longer hospital stays than bacteremia (29.1 +/- 17.4 days as against 13.5 +/- 9.0 days, p less than 0.01) and were diagnosed more time after the first sign of infection (3.28 +/- 1.41 days as against 1.86 +/- 1.10 days, p less than 0.01) . Bacteremia was documented in 13 of the 17 children with focal infection from whom blood cultures were obtained . Seven of 12 had positive stool cultures . The sites of metastatic focal infection were meninges (7 cases), soft tissue (5 cases), joint or bone (4 cases), pleura (2 cases), eye (1 case) . The clinical course of meningitis was fulminant and 6/7 patients died before receiving adequate antimicrobial therapy . One child with meningitis and 9 patients with focal infections at other sites were treated with cefotaxime and were cured or improved.

Eur J Epidemiol, 1986 Jun, 2(2), 124 - 7
Phagocytosis and resistance to Salmonella typhimurium infection in mice fed with lipidic diet; Romano Carratelli C et al.; The peritoneal macrophages from mice on a lipidic diet have shown an increase of surface hydrophobicity of cytoplasmatic membrane . This fact is correlated with a decrease of the phagocytic index and with an impairment of Salmonella typhimurium.

Xenobiotica, 1986 Jun, 16(6), 587 - 93
Mutagenicity of para-nitroso-dimethyl- and diethyl-anilines; Goodall CM et al.; Low concentrations of para-nitroso-dimethylaniline (NdMA) were mutagenic to Salmonella typhimurium TA100 with optimal effect at 1.5 microM in fluctuation assays, without activating enzymes . The diethyl homologue (NdEA) had little or no mutagenic effect at low concentrations, although the bacteriocidal effects of NdMA and NdEA were similar . At higher bacteriocidal concentrations (approximately LC55-LC80) both NdMA and NdEA were mutagenic . NdMA and some other C-nitroso compounds proved carcinogenic in animal bioassays, and further research is needed to assess the human hazard from exposure to C-nitroso compounds in food, medicines or industry.

Mol Gen Genet, 1986 Jun, 203(3), 435 - 44
Relationship between pseudo-HPr and the PEP: fructose phosphotransferase system in Salmonella typhimurium and Escherichia coli; Geerse RH et al.; We have studied in Salmonella typhimurium and Escherichia coli the properties of pseudo-HPr suppressor mutations . These mutations suppressed the defects in a ptsH mutant which lacks HPr, one of the enzymes of the phosphoenolpyruvate: carbohydrate phosphotransferase system . The suppressor mutation was mapped in S . typhimurium at 3 min, closely linked to leu . The corresponding chromosomal fragment of 1.7 kb from S . typhimurium and E . coli (extending clockwise from ilvH) was cloned . In a maxicell system a protein with an approximate molecular weight of 36,000 was synthesized . Pseudo-HPr suppressor mutations (fruR) and a deletion extending clockwise from leu resulted in the constitutive expression of the fru operon containing the genes for IIFru (fruA), IIIFru (fruB), fructose 1-phosphate kinase (fruK) and pseudo-HPr (fruF) . fruR probably codes for a repressor of the fru operon . Tn10 mutagenesis revealed the following order of genes in the fru operon: fruB-(fruK, fruF)-fruA . Pseudo-HPr activity could replace HPr in PEP-dependent phosphorylation of PTS carbohydrates . IIIFru could be phosphorylated both via HPr and pseudo-HPr, since mutants lacking pseudo-HPr activity were still able to phosphorylate fructose in the presence of added HPr . Both the pseudo-HPr suppressor mutations at 3 min and the deletion extending from leu had an additional phenotype . Introduction of these mutations or deletions was always accompanied by disappearance of PEP synthase activity . Complementation of such a mutant with the cloned fragments reversed both phenotypes at the same time . Possibly, the fruR gene product acts as an activator of the gene coding for PEP synthase.

Mol Gen Genet, 1986 Jun, 203(3), 389 - 96
Primary and secondary structural homologies between the HIS4 gene product of Saccharomyces cerevisiae and the hisIE and hisD gene products of Escherichia coli and Salmonella typhimurium; Bruni CB et al.; A detailed comparative analysis of the Escherichia coli and Salmonella typhimurium hisIE and hisD gene products and the functionally equivalent, single, HIS4 gene product of Saccharomyces cerevisiae permitted several insights concerning the relationship between these genes . Our analysis supports the idea that HIS4 results from the fusion of his IE and hisD . The comparison permitted a more precise definition of the functional domains of hisI/HIS4A and hisE/HIS4B as well as the two functional domains of hisD/HIS4C . The homologies between the bacterial and yeast sequences suggest a region of the hisD/HIS4C protein that may constitute one of the active centres . A large fragment at the amino terminal region of the yeast protein is missing from the bacterial hisIE gene product and is probably not needed for catalytic activity . Another region of non-homology in the yeast protein is probably a peptide bridge connecting the HIS4AB domain to HIS4C . Although the overall homology at the level of amino acid sequence is modest (about 38%) there is a striking similarity when the hydropathic patterns and predicted secondary structural configurations of these proteins are compared.

J Environ Sci Health B, 1986 Jun, 21(3), 243 - 50
Evaluation of beta-naphthoxyacetic acid for mutagenic activity in the Salmonella/mammalian microsome assay; Rashid KA et al.; Beta-naphthoxyacetic acid (BNOA) is used as a plant growth regulator on tomatoes and strawberries . It is the active ingredient in Blossom-Set and Berry-Set, two plant hormone sprays for fruit-set . The mutagenic activity of BNOA was evaluated in four strains of Salmonella typhimurium (TA97, TA98, TA100 and TA1535) in the presence and absence of liver microsomal and cytosolic enzymes derived from Aroclor induced rats . BNOA did not produce any significant increase (p less than 0.05) in the reversion of any of the four tester strains in the standard plate incorporation assay . Results of the agar overlay toxicity tests indicates that the chemical shows toxic effects at concentrations above 500 micrograms/plate . It was concluded that under the conditions of these tests, BNOA did not exhibit any mutagenic activity.

Can J Microbiol, 1986 Jun, 32(6), 498 - 504
Granule contents from rat polymorphonuclear leukocytes: antimicrobial properties and characterization; Hodinka RL et al.; The nonoxidative antibacterial properties of isolated rat polymorphonuclear leukocyte granule contents were examined using Salmonella typhimurium LT-2 and a series of progressively rough lipopolysaccharide mutants of this strain as target bacteria . The granule extract was most active at 37 degrees C, with a substantial decrease in activity observed at lower temperatures . Deep rough bacterial mutants were killed best within a pH range of 6-8, while killing of mutants with increased lipopolysaccharide content was most efficient at an acid pH of 5 . The activity of the extract was dependent on incubation time but was independent of the number of bacterial cells present in the assay mixture . The killing action of the granule extract was inhibited by the cations Na+, K+, Mg2+, Ca2+, and Fe2+ . The degree of inhibition was dependent on the type and concentration of ion used . Rough mutants grown with aeration to log phase were killed more efficiently than the same mutants grown to stationary phase under static conditions . Also, gram-positive bacteria were more susceptible to the extract than were gram-negative organisms.

Biophys J, 1986 Jun, 49(6), 1229 - 35
Conformational dynamics of two histidine-binding proteins of Salmonella typhimurium; Zukin RS et al.; The Salmonella typhimurium periplasmic histidine-binding J-protein is one of four proteins encoded by the histidine transport operon . Mutant J-protein hisJ5625 binds L-histidine, but does not transport it . The tertiary structure and conformational dynamics of native and mutant J-protein have been compared using steady state fluorescence, fluorescence polarization, and fluorescence energy transfer measurements . The two proteins have different three-dimensional structures and exhibit different responses to histidine binding . Ligand-induced conformational changes were demonstrated in both J-proteins using fluorescence energy transfer (distant reporter method) between the single tryptophan residue per mole of protein and a fluorescein-labeled methionine residue . However, the conformational change of the mutant protein is qualitatively and quantitatively different from that of the wild-type protein . Moreover, the microenvironment of the tryptophan and its distance from the labeled methionine (44A for the wild type, 60A for the mutant J-protein) are different in the two proteins . In conclusion, these results indicate that the specific conformational change induced in the wild type J-protein is a necessary requirement for the transport of L-histidine.

Mutat Res, 1986 Jun, 164(3), 139 - 43
Mutagenicity towards Salmonella typhimurium of some known genotoxic agents, activated by isolated hepatocytes of monkey (Macaca fascicularis) . Comparison with isolated human hepatocytes; Neis JM et al.; This paper describes some striking differences between isolated human and monkey hepatocytes in their capacity to activate some known genotoxic agents into products mutagenic towards Salmonella typhimurium . Isolated monkey hepatocytes, in contrast to human hepatocytes, appeared to activate benzidine (BZ), N-acetylbenzidine (MABZ), N,N'-diacetylbenzidine (DABZ), 2-aminofluorene (2-AF) and 2-acetylaminofluorene (2-AAF) poorly . With monkey hepatocytes BZ was slightly more mutagenic than DABZ, whereas with human hepatocytes DABZ was more active than BZ . N-Nitrosodimethylamine (DMN) and N-nitrosodiethylamine (DEN) were also found to be poorly mutagenic when activated by monkey hepatocytes, unlike the human hepatocytes . However, the polycyclic arylhydrocarbons benzo{a}pyrene (B{a}P) and 7,12-dimethylbenzanthracene (7,12-DMBA) were highly active in the presence of monkey hepatocytes, unlike the human hepatocytes . A metabolic study showed that monkey liver preparations seem to possess a higher monooxygenase activity towards B{a}P than human liver preparations.

Mol Pharmacol, 1986 Jun, 29(6), 629 - 36
An Ab initio study of the relationship between nitroarene mutagenicity and electron affinity; Maynard AT et al.; Electron affinities, approximated by lowest unoccupied molecular orbital (LUMO) energies, were determined for an extensive group of nitrated polycyclic aromatic hydrocarbons by ab initio methods at the STO-3G level . Significant correlations were demonstrated between nitroarene LUMO energy and the corresponding mutagenic activity in Salmonella typhimurium strains TA98, TA100, TA1537, and TA1538 . An analogous correlation using Huckel calculations was substantially poorer . A correlation between nitro group rotation and LUMO energy was related to pi-conjugation about the C--N bond . Analysis of aryl substituent effects on nitrenium ion stability implicated additional nitro substitution in certain systems to be destabilizing . The results suggest a means for predicting nitroarene mutagenic activity and for assessing the role of metabolic intermediates.

J Bacteriol, 1986 Jun, 166(3), 1113 - 7
High A + T content conserved in DNA sequences upstream of leuABCD in Escherichia coli and Salmonella typhimurium; Haughn GW et al.; The nucleotide sequence of over 800 base pairs of DNA upstream of leuP was determined for Escherichia coli and Salmonella typhimurium . In both of these enteric bacteria, approximately 500 base pairs of A + T-rich sequences separates leuP from an upstream open reading frame . Although these A + T-rich sequences share little homology, the distribution of A + T base pairs within the region is strikingly conserved . Deletion of the A + T-rich sequences upstream of the E . coli leu operon does not markedly affect the strength of the leu promoter in vivo.

Immunology, 1986 Jun, 58(2), 225 - 30
Impairment of lymphocyte proliferative responses and interleukin-2 production in susceptible (C57BL/6) mice infected with Salmonella typhimurium; Deschenes M et al.; C57BL/6 (susceptible) and A/J (resistant) mice were infected intravenously with a temperature-sensitive mutant of Salmonella typhimurium . In C57BL/6 mice a marked depression of the proliferative response of spleen cells to B and T mitogens occurred and was maximal at 2-3 weeks post-infection, whereas only minor changes were found in A/J mice . This immunodepression was mediated, at least in part, by adherent cells . Moreover, spleen cells from infected C57BL/6 mice did not produce interleukin-2 (IL-2) after concanavalin A stimulation . The impairment of IL-2 production was not related to a defect in IL-1 release . The addition of IL-2 to spleen cells did not restore their ability to respond to mitogens . The depression of mitogenic responses in infected C57BL/6 mice occurred at a time when increased resistance was present.

Environ Res, 1986 Jun, 40(1), 155 - 63
Mutagenicity of used crankcase oils from diesel and spark ignition automobiles; Dutcher JS et al.; The Salmonella mutagenicity assay was used to compare the mutagenic activity of used crankcase oil (UCO) from diesel and spark-ignition (gasoline) engine passenger cars . UCO samples were obtained during periodic oil changes from 9 spark-ignition and 10 diesel-powered vehicles . Five samples of unused motor oil were also tested . Direct tests of UCO did not detect mutagenic activity in Salmonella typhimurium strain TA-98 . Therefore, an extraction procedure was used to concentrate the mutagens and remove interfering chemicals . Extracts were tested both with and without Aroclor-1254-induced rat liver homogenate fraction (S-9) . Dose-dependent mutagenicity with and without S-9 was observed in both diesel and spark-ignition engine UCO extracts . Mutagenic activity was also found in unused oil extracts, but it was lower than that in UCO extracts and generally required addition of S-9 . The mutagenic potency of diesel UCO extracts was similar to that of gasoline UCO extracts, both with and without addition of S-9 . This indicated that potential health risks associated with disposal, handling, and recycling of diesel UCO may not be significantly different from those of UCO from gasoline engines.

Mutat Res, 1986 Jun, 161(1), 39 - 48
Mutagenic sterol hydroperoxides; Smith LL et al.; Sterol hydroperoxides 3 beta-hydroxy-5 alpha-cholest-6-ene-5-hydroperoxide and 3 beta-hydroxycholest-5-ene-7 alpha-hydroperoxide show weak dose-response direct mutagenicity towards Salmonella typhimurium strain TA 1537 in a liquid medium incubation bioassay . Responses were compromised by metabolism of the sterol hydroperoxides and by phase separation during the incubation period . Mutagenicity responses were increased by added superoxide dismutase but diminished by added rat liver S9 enzymes and abolished by added catalase . Catalase also abolished the stimulatory effect of superoxide dismutase . These results indicate that superoxide and peroxide be implicated in the mutagenicity responses.

J Infect Dis, 1986 Jun, 153(6), 1119 - 25
The colonization of Peyer's patches by a strain of Salmonella typhimurium cured of the cryptic plasmid; Hackett J et al.; We cured a strain of Salmonella typhimurium of its cryptic plasmid and confirmed that orally administered cured strains lost virulence for mice . Loss of the cryptic plasmid rendered the S . typhimurium strain sensitive to the bactericidal action of normal human serum . However, loss of the plasmid did not change the ability of the strain to associate with HeLa cells in tissue culture . Furthermore, when administered orally to mice, both the plasmid-containing and plasmid-free strains invaded the Peyer's patches of the small intestine to the same extent, and both were capable of inducing resistance to oral challenge with virulent S . typhimurium . When injected intraperitoneally, the cured strain was eliminated rapidly, whereas the parental strain persisted . We also showed that the cured strain did not contain a plasmid copy in the chromosome . We propose that although the plasmid-cured strain of S . typhimurium is able to colonize Peyer's patches, it cannot survive when administered intraperitoneally because it is susceptible to elimination by macrophages.

Cancer Res, 1986 Jun, 46(6), 2760 - 6
Bacterial and mammalian cell mutagenicity of four optically active bay-region 3,4-diol-1,2-epoxides and other derivatives of the nitrogen heterocycle dibenz{c,h}acridine; Wood AW et al.; The mutagenic activities of the enantiomers of the diastereomeric pair of bay-region 3,4-diol-1,2-epoxides of the nitrogen heterocycle, dibenz{c,h}acridine, have been evaluated in histidine-dependent strains of Salmonella typhimurium and in an 8-azaguanine-sensitive line of Chinese hamster cells . In strains TA 98 and TA 100 of S . typhimurium the pair of enantiomers with {1R,2S,3S,4R} and {1S,2R,3R,4S} absolute configuration and the benzylic hydroxyl group trans to the epoxide oxygen are 2 to 4 times more mutagenic than the {1S,2R,3S,4R} and {1R,2S,3R,4S} isomers in which the benzylic hydroxyl and epoxide oxygen are cis . In both strains of bacteria there is very little difference in mutagenic activity between the enantiomers of each diastereomer . In contrast to these results in bacteria, the bay-region 3,4-diol-1,2-epoxide isomer with {1R,2S,3S,4R} absolute configuration is 5 to 7 times more mutagenic to Chinese hamster V79 cells than are the other 3 isomers . The enantiomeric pair of bay-region tetrahydro-1,2-epoxides of dibenz{c,h}acridine are at least 7 times more mutagenic than the diol-epoxides in the Salmonella assay, and no difference in mutagenic activity is observed between enantiomers . In the Chinese hamster V79 cell system, however, the tetrahydro-1,2-epoxide with {1R,2S} absolute configuration is 2- to 3-fold more mutagenic than its enantiomer with {1S,2R} absolute configuration . Homogeneous rat liver epoxide hydrolase does not catalyze the hydration of the diol-epoxide isomers to nonmutagenic products, although the tetrahydroepoxides, especially the tetrahydro-3,4-epoxide, are metabolized by the enzyme . Results of metabolic activation experiments with the bacterial mutagenesis system and microsomes from Aroclor 1254-treated rats are consistent with the mutagenicity data described above and support the concept that dibenz{c,h}acridine is metabolically activated to a bay-region diol-epoxide . Notably: (a) 3,4-dihydrodibenz{c,h}acridine, the expected precursor of a bay-region tetrahydroepoxide, is metabolized to a potent mutagen; (b) racemic dibenz{c,h}acridine 3,4-dihydrodiol is metabolized to products which are several-fold more mutagenic than are products of the metabolism of dibenz{c,h}acridine or its 1,2- or 5,6-dihydrodiols; and (c) the tetrahydro-3,4-diol, which lacks the isolated bay-region double bond, is not metabolically activated to a bacterial mutagen.

Microb Pathog, 1986 Jun, 1(3), 269 - 74
Expression of the innate resistance gene Ity in mouse Kupffer cells infected with Salmonella typhimurium in vitro; Harrington KA et al.; Early innate resistance to salmonellae in mice is controlled by the chromosome 1 gene Ity which regulates the in vivo net growth rate of bacteria in the RES by an unknown mechanism . It similarly controls innate resistance to Leishmania donovani, BCG and Mycobacterium lepraemurium . Murine Kupffer cell cultures were infected with virulent Salmonella typhimurium and followed for 12 h . Multiresistant organisms were used so that the antibiotics in the medium could not interfere with the results; extracellular bacteria were removed by repeated washes . Monolayers from resistant Ityr (C3H/He, CBA, A/J) and Ityr/s (B10 x A/J)F1 mice resisted infection with S . typhimurium C5 better than those from susceptible Itys (DBA/1, BALB/c, B10.M) mice, which were progressively lost from the culture plates at a faster rate than resistant monolayers . Organisms were clearly visible inside large vacuoles in the macrophages . The results confirm and amplify results of others on salmonella-infected peritoneal and splenic macrophages, and support the view that the Ity gene is expressed as a function of macrophages.

Mutat Res, 1986 Jun, 174(2), 85 - 8
Mutagenic activation of aflatoxin B1 by several forms of purified cytochrome P-450; Ishii K et al.; Metabolic activation by several forms of purified cytochrome P-450 of aflatoxin B1 to a product(s) mutagenic to Salmonella typhimurium TA100 was examined . Of the 5 forms of cytochrome P-450 purified from liver microsomes of untreated and PCB-treated male rats, a constitutive form purified from untreated male rats, P-450-male, and a high-spin form of cytochrome P-450, P-448-H, from PCB-treated rats were highly active.

J Bacteriol, 1986 Jun, 166(3), 857 - 65
Association of RNA polymerase having increased Km for ATP and UTP with hyperexpression of the pyrB and pyrE genes of Salmonella typhimurium; Jensen KF et al.; We investigated the transcription kinetics of RNA polymerase from an rpoBC mutant of Salmonella typhimurium which showed highly elevated, constitutive expression of the pyrB and pyrE genes as well as an increased cellular pool of UTP . When bacterial cultures containing an F' lac+ episome were induced for lac operon expression, the first active molecules of beta-galactosidase were formed with a delay of 73 +/- 3 s in rpo+ cells . The corresponding time was 104 to 125 s for cells carrying the rpoBC allele, indicating that this mutation causes a reduced RNA chain growth rate . In vitro the purified mutant RNA polymerase elongated transcripts of both T7 DNA and synthetic templates more slowly than the parental enzyme at a given concentration of nucleoside triphosphates . This defect was found to result from four- to sixfold-higher Km values for the saturation of the elongation site by ATP and UTP . The saturation kinetics of the RNA chain initiation step also seemed to be affected . The maximal elongation rate and Km for GTP and CTP were less influenced by the rpoBC mutation . Open complex formation at the promoters of T7 DNA and termination of the 7,100-nucleotide transcript showed no significant difference between the parental and mutant enzymes . Together with the phenotype of the rpoBC mutant, these results indicate that expression of pyrB and pyrE is regulated by the mRNA chain growth rate, which is controlled by the cellular UTP pool . The rate of gene expression is high when the saturation of RNA polymerase with UTP is low and vice versa.

J Bacteriol, 1986 Jun, 166(3), 1022 - 7
Influence of modification next to the anticodon in tRNA on codon context sensitivity of translational suppression and accuracy; Bouadloun F et al.; Effects on translation in vivo by modification deficiencies for 2-methylthio-N6-isopentenyladenosine (ms2i6A) (Escherichia coli) or 2-methylthio-N6-(4-hydroxyisopentenyl)adenosine (ms2io6A) (Salmonella typhimurium) in tRNA were studied in mutant strains . These hypermodified nucleosides are present on the 3' side of the anticodon (position 37) in tRNA reading codons starting with uridine . In E . coli, translational error caused by tRNA was strongly reduced in the case of third-position misreading of a tryptophan codon (UGG) in a particular codon context but was not affected in the case of first-position misreading of an arginine codon (CGU) in another codon context . Misreading of UGA nonsense codons at two different positions was codon context dependent . The efficiencies of some tRNA nonsense suppressors were decreased in a tRNA-dependent manner . Suppressor tRNA which lacks ms2i6A-ms2io6A becomes more sensitive to codon context . Our results therefore indicate that, besides improving translational efficiency, ms2i6A37 and ms2io6A37 modifications in tRNA are also involved in decreasing the intrinsic codon reading context sensitivity of tRNA . Possible consequences for regulation of gene expression are discussed.

Infect Immun, 1986 Jun, 52(3), 828 - 33
Natural and recombinant interferons inhibit epithelial cell invasion by Shigella spp; Niesel DW et al.; The effect of natural and recombinant interferons (IFNs) on the abilities of Shigella flexneri, S . sonnei, and Salmonella typhimurium to invade different human and murine cells was examined . Pretreatment of cell monolayers with natural and recombinant IFNs reduced the number of Shigella-infected cells in a dose-dependent manner . Establishment of an anti-invasive cellular state was time dependent, requiring 10 h for 50% inhibition of bacterial invasion . The inhibitory effect of IFN was species specific, with human or murine IFN effective against homologous but not heterologous cells . Gamma IFN was slightly more potent than alpha IFN at inhibiting bacterial invasion . Inhibition of Shigella invasion was dependent on the challenge dose of bacteria . Little inhibition of invasion was seen when cells were pretreated with low concentrations of IFN and challenged with high multiplicities of infection of Shigella sp . In contrast to Shigella invasion, the maximum inhibitory effect of IFN on Salmonella invasion of cells was observed at low levels (5 to 50 U) of IFN . These results suggest that Shigella and Salmonella invasions occur at unique sites on eucaryotic cells or by different penetration mechanisms . More importantly, these data suggest that IFN may play a significant role in host defense against Shigella and Salmonella infections.

J Biochem Toxicol, 1986 Jun, 1(2), 43 - 55
Synthesis and genotoxicity of acetoxyoxirane, the epoxide of vinyl acetate; Simon P et al.; Acetoxyoxirane, the epoxide of vinyl acetate and a potential reactive intermediate, was synthesized and characterized by 13C-nuclear magnetic resonance (13C-NMR) and mass spectroscopy . The compound induced lesions (endonuclease-sensitive and alkali-labile sites) in supercoiled PM2 DNA in vitro and was directly mutagenic toward Salmonella typhimurium TA100 . The mutagenicity of the epoxide in phosphate buffer (pH 7.4, 37 degrees C) decreased, with an initial half-life of 2.8 minutes, and mutagenicity was completely abolished by addition of S-9 mix . Acetoxyoxirane did not induce unscheduled DNA synthesis on incubation with Syrian hamster embryo fibroblasts (SHE cells) . These findings may possibly be explained by an effective inactivation of acetoxyoxirane by esterases when these are present in the biological system . This view is consistent with the lack of acetoxyoxirane detected in rat liver microsomal incubations of vinyl acetate.

Mol Gen Genet, 1986 Jun, 203(3), 382 - 8
Nucleotide sequence of the Escherichia coli hisD gene and of the Escherichia coli and Salmonella typhimurium hisIE region; Chiariotti L et al.; In this paper we report the nucleotide sequence of the hisD gene of Escherichia coli and of the his IE region of both E . coli and Salmonella typhimurium . The hisD gene codes for a bifunctional enzyme, L-histidinol:NAD+ oxidoreductase, of 434 amino acids with a molecular mass of 46,199 daltons . We established that the hisIE region of both S . typhimurium and E . coli is composed of a single gene and not, as previously believed, of two separate genes . The derived amino acid sequence indicates that the hisIE gene codes for a bifunctional protein of 203 amino acids with an approximate molecular mass of 22,700 daltons . We also determined the nucleotide sequence of a deletion mutant in S . typhimurium which abolishes the hisF and hisI functions but retains the hisE function . We deduced that the mutant produces a chimeric protein fusing the aminoterminal region of the upstream hisF gene to the carboxyl-terminal domain of the hisIE gene which encodes for the hisE function . In view of these results the structural and functional organization of the histidine operon in enteric bacteria needs to be revised . The operon is composed of only 8 genes and the pathway leading to the biosynthesis of the amino acid requires 11 enzymatic steps.

J Appl Bacteriol, 1986 Jun, 60(6), 501 - 11
Peroxide sensitivity of cold-shocked Salmonella typhimurium and Escherichia coli and its relationship to minimal medium recovery; Mackey BM et al.; Cold-shocked Salmonella typhimurium displayed minimal medium recovery (MMR), viable counts on M9 minimal agar being much higher than those on tryptone soya yeast extract agar (TSYA) . The addition of catalase to TSYA restored counts to the level found on M9 agar . Peroxide concentrations between 12 and 30 mumol/l were measured in TSYB but none was detected in M9 medium . Cold-shocked cells were sensitive to reagent hydrogen peroxide at a concentration similar to that found in TSYB . The minimal medium recovery phenomenon of cold-shocked cells is thus a manifestation of peroxide sensitivity . Changing the composition of growth media affected both cellular catalase activity and the magnitude of the MMR effect but the two properties were not directly related . Factors additional to cellular catalase activity must therefore affect susceptibility to peroxide following cold shock . Mutational loss of catalase, exonuclease III or recA-dependent DNA repair functions all increased the sensitivity of cold-shocked Escherichia coli to the inhibitory effects of peroxide present in rich medium . The peroxide resistant fraction of a cold-shocked population of Salm . typhimurium (i.e . those cells able to grow on TSYA) was more resistant to gamma radiation than the population as a whole . Cold shock thus sensitizes cells to more than one form of oxidative stress . Prior exposure of growing cells to 30 mumol/l hydrogen peroxide abolished their sensitivity to rich medium following cold shock implying that Salm . typhimurium contains an inducible system protecting against oxidative stress.

Virology, 1986 Jun, 151(2), 274 - 85
Isolation of temperature-sensitive mutants of bacteriophage MB78 and correlation between the physical and genetic maps; Verma M et al.; In order to study the biochemistry and genetics of the virulent virus MB78 of Salmonella typhimurium, 31 temperature-sensitive mutants of the phage were isolated following mutagenesis with N-methyl-N'-nitro-N-nitrosoguanidine . These have been classified into six complementation groups (A through F) . Linkage between different complementation groups has been mapped by using two factor crosses between representative members of each group . To correlate the physical and genetic maps of the phage, complementation between bacterial clones carrying plasmids with EcoRI fragments of the phage DNA as inserts and the ts mutants was studied . Good correlation between the physical and genetic maps has been obtained . Tentative locations of the ts mutations on the phage genome have thus been determined.

Mutat Res, 1986 Jun, 161(1), 29 - 37
Rat and hamster hepatocyte-mediated induction of SCEs and mutation in V79 cells and mutation of salmonella by aminofluorene and dimethylnitrosamine; Langenbach R et al.; Aminofluorene (AF) and dimethylnitrosamine (DMN) were examined for their ability to induce multiple genetic endpoints after rat and hamster hepatocyte metabolic activation . The endpoints measured included mutations at the Na+/K+-ATPase (ouabain resistance) and hypoxanthine-guanine-phosphoribosyltransferase (6-thioguanine resistance) loci, and sister-chromatid exchanges (SCEs) in Chinese hamster V79 cells, and mutation of Salmonella typhimurium strains TA98 and TA100 . AF, with rat and hamster hepatocyte activation, induced only low levels of mutations at either loci in V79 cells but did induce SCEs . Mutation of Salmonella by AF after hepatocyte activation also occurred and was a sensitive endpoint for detecting this aromatic amine . DMN induced high levels of mutations at both loci in V79 cells in addition to SCEs in the presence of hepatocytes from both species . DMN was also mutagenic to Salmonella, but only with hamster hepatocytes . Salmonella did not respond as strongly to DMN as the V70 cells . Hamster hepatocytes were more active than rat hepatocytes in activating both carcinogens . The results indicate the variable sensitivity of the genetic endpoints and species differences in activation for two potent chemical carcinogens.

J Bacteriol, 1986 Jun, 166(3), 1013 - 21
Pleiotropic effects induced by modification deficiency next to the anticodon of tRNA from Salmonella typhimurium LT2; Ericson JU et al.; A strain of Salmonella typhimurium LT2 was isolated, which harbors a mutation acting as an antisuppressor toward an amber suppressor derivative, supF30, of tRNATyr1 . The mutant is deficient in cis-2-methylthioribosylzeatin{N6-(4-hydroxyisopentenyl)-2-me thylthioadenosine, ms2io6A}, which is a modification normally present next to the anticodon (position 37) in tRNA reading codons starting with uridine . The gene miaA, defective in the mutant, is located close to and counterclockwise of the purA gene at 96 min on the chromosomal map of S . typhimurium with the gene order mutL miaA purA . Growth rate of the mutant was reduced 20 to 50%, and the effect was more pronounced in media supporting fast growth . Translational chain elongation rate at 37 degrees C was reduced from 16 amino acids per s in the wild-type cell to 11 amino acids per s in the miaA1 mutant in the four different growth media tested . The cellular yield in limiting glucose, glycerol, or succinate medium was reduced for the miaAI mutant compared with wild-type cells, with 49, 41, and 57% reductions, respectively . The miaAI mutation renders the cell more sensitive or resistant toward several amino acid analogs, suggesting that the deficiency in ms2io6A influences the regulation of several amino acid biosynthetic operons . We suggest that tRNAPhe, lacking ms2io6A, translates a UUU codon in the early histidine leader sequence with lowered efficiency, leading to repression of the his operon.

J Immunol, 1986 Jun 1, 136(11), 4006 - 12
Polyclonal activation of rat B cells . I . A single mitogenic signal can stimulate proliferation, but three signals are required for differentiation; Stunz LL et al.; A water-soluble, proteinaceous preparation derived from the cell walls of Salmonella typhimurium Re mutants has recently been tested in our laboratory for its ability to act as a mitogen for rat lymphocytes . We have found this preparation (STM) to be a potent stimulator of B lymphocyte proliferation, as measured both by 3H-TdR incorporation and by cell cycle analysis performed with flow cytofluorometry . STM stimulates approximately 50% of rat B cells to enter cycle . Previous investigations by others have shown that at least two sets of signals are required for B cell differentiation; a) proliferation signals that may consist of both a stimulator of B cell conversion from G0 to G1 and growth factors, and b) differentiation signals that probably include at least two B cell differentiation factors (BCDF) . When STM was tested in a differentiation system it did not drive purified B cells to differentiate to PFC, either alone or when supplemented with a supernatant from concanavalin A-stimulated spleen cells (CAS) . However, when both CAS and dextran sulfate (DXS) were supplied to the STM-stimulated cells, a large number of PFC resulted . DXS does not act by stimulating an additional, CAS-responsive B cell subset, since it has only a marginal effect upon 3H-TdR uptake and does not increase the number of B cells in cycle when used together with STM . We postulate that the two agents may be acting sequentially: STM stimulates the B cells to proliferate, and DXS drives the proliferating cells to become responsive to CAS . This suggests that the signals for B cell differentiation must consist of at least three activities: a trigger to stimulate the cells to proliferate, a factor to drive the cells to a BCDF-responsive state, and a BCDF that can drive the cells to secrete antibody.

J Biol Chem, 1986 May 15, 261(14), 6444 - 9
Cloning, sequencing, and species relatedness of the Escherichia coli cca gene encoding the enzyme tRNA nucleotidyltransferase; Cudny H et al.; The Escherichia coli cca gene which encodes the enzyme tRNA nucleotidyltransferase has been cloned by taking advantage of its proximity to the previously cloned dnaG locus . A series of recombinant bacteriophages, spanning the chromosomal region between the dnaG and cca genes at 66 min on the E . coli linkage map, were isolated from a lambda Charon 28 partial Sau3A E . coli DNA library using recombinant plasmids containing regions between dnaG and cca as probes . Two of the recombinant phage isolates, lambda c1 and lambda c4, contained the cca gene . A BamHI fragment from lambda c1 was subcloned into pBR328, and cells containing this recombinant plasmid, pRH9, expressed tRNA nucleotidyltransferase activity at about 10-fold higher level than the wild type control . The cca gene was further localized to a 1.4-kilobase stretch of DNA by Bal31 deletion analysis . The nucleotide sequence of the cca gene was determined by the dideoxy method, and revealed an open reading frame extending for a total of 412 codons from an initiator GTG codon that would encode a protein of about 47,000 daltons . Southern analysis using genomic blots demonstrated that the cca gene is present as a single copy on the E . coli chromosome and that there is no homology on the DNA level between the E . coli cca gene, and the corresponding gene in the Bacillus subtilis, Saccharomyces cerevisiae, Petunia hybrida, or Homo sapiens genomes . Homology was found only with DNA from the closely related species, Salmonella typhimurium . These studies have also allowed exact placement of the cca gene on the E . coli genetic map, and have shown that it is transcribed in a clockwise direction.

J Gen Microbiol, 1986 May, 132 ( Pt 5), 1283 - 95
Effects of in vitro growth phase on the pathogenesis of Salmonella typhimurium in mice; Benjamin WH Jr et al.; The growth phase of a bacterial (Salmonella typhimurium) culture was shown to have pronounced effects on the pathogenic properties of the harvested bacteria . Salmonellae obtained from a culture in primary (exponential) growth phase (PP) were more readily cleared from the blood and more readily killed by phagocytes than were salmonellae obtained from a more slowly growing secondary growth phase (SP) culture . PP salmonellae were observed to cause death of mice sooner than SP salmonellae . This appeared to be because the more rapid growth of PP, as compared to SP, salmonellae continued in the liver and spleen for several hours following intravenous injection, and more than compensated for their high in vivo death rate . As a result, within 4 h there were approximately 10-fold more live salmonellae in the spleens and livers of mice that had received PP, as compared to SP, salmonellae . This 10-fold difference was maintained until the death of the mice, indicating that after the first 4 h post-inoculation, the net in vivo growth of the salmonellae was the same regardless of their growth phase in the inoculating culture . This transition between PP and SP salmonellae occurred long before a dense stationary phase culture was obtained . Salmonellae grown in minimal media exhibited the biological properties of SP salmonellae and never entered as rapid a growth phase as did salmonellae in complete media.

Pharmacol Res Commun, 1986 May, 18(5), 491 - 501
Mutagenic activity of the dacarbazine analog p-(3,3-dimethyl-1-triazeno)benzoic acid potassium salt in bacterial cells; Tamaro M et al.; The mutagenic activity of the antimetastatic agent p-(3,3-dimethyl-1-triazeno)benzoic acid potassium salt (DM-COOK) was studied in procaryotic cells and compared with that of dacarbazine (DTIC) which is clinically used in the management of human neoplasms . The results indicated that DM-COOK has a very low mutagenic activity on the Salmonella typhimurium strains tested, while it is more effective in inducing trp+ revertants in E . coli B strains . The magnitude of these effects was always less pronounced than that displayed by DTIC . The mutagenic activity of DM-COOK appeared to be independent from the addition of a metabolic activating system and had a different pattern from that displayed by MM-COOK . It is therefore unlikely that DM-COOK acts through conversion into the monomethyl derivative.

Poult Sci, 1986 May, 65(5), 922 - 8
Use of egg washwater pH to prevent survival of Salmonella at moderate temperatures; Holley RA et al.; The survival and thermal resistance of Salmonella typhimurium N+L141083 was examined in egg washwater at moderate temperatures over a range of pH values . Salmonella were able to grow at 38 and 42 C when washwater pH was less than or equal to 9.5, but substantial lethality was noted at greater than or equal to pH 10 . At pH 10.5 and 11, Salmonella were eliminated within 5 hr . At 6 C, Salmonella levels were maintained for 18 hr without lethality up to pH 11 . At pH 11, some lethality was noted after 5 hr . A D42 value at pH 7.0 could not be calculated, but at pH 10, a value of 40.8 sec was determined . Narrow range pH paper (pH 8 to 10) responded to egg washwater contact at or above pH 10 with a clear color reaction . Below pH 10, the paper signalled the need for addition of alkaline detergent to prevent the growth of Salmonella.

J Appl Bacteriol, 1986 May, 60(5), 381 - 7
The destruction of Salmonella typhimurium in chicken exudate by different freeze-thaw treatments; Obafemi A et al.; Antibacterial treatments for frozen poultry, including holding at -5 degrees C and slow thawing at 4 degrees C to which exponential phase cells of Salmonella typhimurium were susceptible, were found to be relatively ineffective against stationary phase cells . Exposure of the latter, however, to a pre-freezing triple stress treatment of cold-shock exposure at 5 degrees C to a solution containing 5 mg/l of free available chlorine in 1% succinic acid (pH 2.5) for 20 min substantially lowered the resistance of the cells to subsequent freezing, storage and thawing in poultry flesh exudate . Cell survival was further decreased by storage of exudate at -18 degrees C for 28 d and this reduced the proportion of stationary phase cells to less than 1% of initial numbers, with a concomitant increase in sensitivity to deoxycholate . Such a combined pre-treatment may have practical potential for salmonella decontamination in the production of frozen poultry.

J Leukoc Biol, 1986 May, 39(5), 521 - 32
The in vitro mitogenic response to intact bacteria by murine B cells does not predict in vivo susceptibility to Salmonella typhimurium; Elkins K et al.; We are interested in developing in vitro culture systems that will permit immune responses to intact Salmonella typhimurium, since these systems would have certain advantages over in vivo infection models for the characterization of the host's responding cell types . In this report, the in vitro proliferative response of nonimmune murine spleen cells to four different killed preparations of S . typhimurium, strain TML (TML), are examined . These studies show that UV-killed TML, heat-killed TML, glutaraldehyde-killed TML, and acetone-killed and dried TML, all elicit a nonspecific mitogenic spleen cell response in vitro, as does a live, avirulent, temperature-sensitive mutant of TML, TS27 . This response reaches a maximum on day 2 after initiation of culture, which is similar to the time course of a conventional lipopolysaccharide (LPS) response . Unlike the LPS response, little 3H-thymidine incorporation is observed in low-density cultures (2 X 10(5) cells/well), which suggests a critical role for accessory cells . The responding cell types include, but are not necessarily limited to, the B-cell population . The response cannot be readily inhibited by polymyxin B, which binds specifically to the lipid A portion of LPS . Thus, the bacterial components required for mitogenicity are not yet definitively identified . A survey of the mitogenic responses of lymphocytes from various inbred mouse strains, including the C3H/HeJ LPS hyporesponsive strain, indicates that all B cells tested are capable of proliferating vigorously in response to intact TML, regardless of the in vivo susceptibility to virulent infection . These results also emphasize the importance of assessing the nonspecific components of the immune response when studying the specific immune response to intact S . typhimurium.

Infect Immun, 1986 May, 52(2), 504 - 8
Delayed-type hypersensitivity and immunity to Salmonella typhimurium; Killar LM et al.; Studies were carried out to correlate immunity and expression of delayed-type hypersensitivity (DTH) in mice of the C3H lineage immunized with an avirulent strain of Salmonella typhimurium (strain SL3235) . This strain belongs to a class of aroA- organisms which are being considered as vaccine strains for humans and veterinary use . In a systematic study, the relationship between the mouse strain and the immunizing dose of strain SL3235 on the development of protective immunity and DTH was examined . It was found that in hypersusceptible C3H/HeJ and C3HeB/FeJ mice, several doses of strain SL3235 afforded protection against intravenous challenge doses as high as 1,300 50% lethal doses . Despite these significant levels of immunity to challenge, mice of these two strains never mounted significant DTH responses following immunization with the doses of strain SL3235 tested, which spanned 3 orders of magnitude . Nonresponsiveness was not due to antigen overload, as all of the mouse strains were comparably colonized with strain SL3235 at the time of DTH elicitation . Further, it was found that the ability of responsive C3H/HeNCrlBR mice to display DTH was dependent on the immunizing dose of strain SL3235 and that a dosage could be found that resulted in increased resistance to challenge in these mice without a concomitant display of DTH . Thus, while both induction of protective immunity and DTH were vaccine dosage dependent in the responsive mouse strain (C3H/HeNCrlBR), DTH was a less sensitive measure of protective immunity than survival . Vaccine dosages ranging over three orders of magnitude failed to yield positive footpads to the Salmonella elicitin in the nonresponsive mice . The data suggest that caution should be observed in interpreting Salmonella DTH tests that are used as screens of immune status to typhoid fever in humans, as the extent of discordance between immunity and DTH in humans is unknown.

Mutat Res, 1986 May, 160(3), 195 - 205
Psoralen photomutagenic specificity in Salmonella typhimurium; Koch WH; The cytotoxic and mutagenic specificity of two therapeutically employed psoralens was examined in several Ames Salmonella typhimurium strains with near ultraviolet light (UVA, 320-400 nm) activation . Photomutagenic activity of 8-methoxypsoralen (8MOP) and 4,5',8-trimethylpsoralen (TMP) was found to be sequence-specific, and additionally was dependent on the level of DNA-repair proficiency . Base-pair substitution photomutagenesis in hisG46 appeared to require plasmid pKM101-mediated "error-prone" repair . Frameshift photomutagenesis was observed in all hisC3076 strains but not in hisD3052 strains . Frameshift mutagenic activity in hisC3076 was enhanced in the absence of uvrB excision repair and increased further by plasmid pKM101 . Phototoxicity was essentially identical in hisC3076, hisD3052 and hisG46 strains; uvrB- excision-repair-deficient bacteria were considerably more susceptible to lethal effects than wild-type parental strains, while the presence of pKM101 had no apparent effect on survival . Finally, the data show that psoralens are potent frameshift photomutagens in Salmonella hisC3076 strains and demonstrate the potential utility of these strains in evaluating photomutagenic and phototoxic activity of new furocoumarin derivatives.

Zhonghua Min Guo Wei Sheng Wu Ji Mian Yi Xue Za Zhi, 1986 May, 19(2), 153 - 9
Effect of EGTA on phagocytosis of Salmonella typhimurium by human neutrophils; Shaio MF et al.; The ingestion of mutant strains of Salmonella typhimurium by human neutrophils was greatly reduced by the presence of ethylene glycol tetra-acetic acid (EGTA) in the reaction mixture . Ingestion of preopsonized bacteria by neutrophils was little affected by Ca++ in the reaction mixture but largely reduced by the presence of EGTA . In addition to chelation of Ca++, EGTA has an adverse effect on neutrophils . In studies of phagocytosis, to avoid this effect, EGTA should not be present in the reaction mixture when it is used to prevent the complement classical pathway activation.

Zhonghua Min Guo Wei Sheng Wu Ji Mian Yi Xue Za Zhi, 1986 May, 19(2), 137 - 52
Complement pathway activity in the opsonization of mutant strains of Salmonella typhimurium; Shaio MF et al.; Two separate complement pathway activities and their interaction in the opsonization of mutant strains of Salmonella typhimurium by human neutrophils were investigated in 1% and 10% sera . In the absence of antibody, all mutant strains of S . typhimurium could activate complement by either the classical or the alternative pathway . The presence of antibody did not alter alternative pathway activity but enhanced the classical pathway activity, especially for those strains possessing intact core structure and in the presence of 10% serum . This effect of antibody on classical pathway activation decreased as the lipopolysaccharide chain length decreased . The finding that the presence of antibody reduced the classical pathway activity in the opsonization of SL 1032 (Rd1) strain in 10% serum was unexpected . This suggests that if complement activity in the absence of antibody is already marked, the presence of antibody cannot increase it further . Inhibition was also found in the interaction between classical and alternative pathways . For SL 1032 (Rd1) strain, in the absence of antibody, either classical or alternative pathway activity alone could be maximally activated in 10% serum and when present together were in competition with each other . The interaction, either enhancement or inhibition, was not only dependent on the individual strain but also on the concentration of serum . In general, enhancement occurred in the presence of 1% serum while inhibition was observed in the presence of 10% serum . Such antagonistic interaction has not previously been reported.

Int J Pept Protein Res, 1986 May, 27(5), 449 - 53
Synthesis of N3-fumaramoyl-L-2,3-diaminopropanoic acid analogues, the irreversible inhibitors of glucosamine synthetase; Andruszkiewicz R et al.; Several analogues of N3-fumaramoyl-L-2,3-diaminopropanoic acid were synthesized and evaluated for inhibition of glucosamine-6-phosphate synthetase activity . The syntheses were accomplished by acylation reaction of N2-tert.-butoxycarbonyl-L-2,3-diaminopropanoic acid (Boc-A2pr) or N2-tert.-butoxycarbonyl-L-2,4-diaminobutanoic acid (Boc-A2-bu) with the N-succinimidoyl esters of several derivatives of alpha, beta-unsaturated acids 2a-d followed by deprotection of the Boc groups . The obtained compounds were tested for inhibition of glucosamine synthetase isolated from Salmonella typhimurium and Saccharomyces cerevisiae . The results indicated that among the synthesized compounds, N3-4-methoxyfumaroyl-L-2,3-diaminopropanoic acid (FMDP) was the most powerful inhibitor of glucosamine synthetase.

J Assoc Off Anal Chem, 1986 May-Jun, 69(3), 510 - 2
Production and isolation of aflatoxin M1 for toxicological studies; Hsieh DP et al.; One hundred mg aflatoxin M1 was produced and purified for toxicological studies . Aspergillus flavus NRRL 3251 was cultured on rice to produce aflatoxins B1, B2, M1, and M2, B1 and B2 were separated from M1 and M2 by a normal phase low pressure liquid chromatography (LC) column . M1 was then separated from M2 by a reverse phase low pressure LC column . Recoveries of aflatoxins from the LC columns were about 90% . The purified M1 was confirmed by ultraviolet-visible spectrometry, mass spectrometry, nuclear magnetic resonance spectrometry, optical rotation, and its mutagenicity to Salmonella typhimurium TA98.

Bioorg Khim, 1986 May, 12(5), 699 - 707
{Genes encoding the beta-subunit of bacterial RNA-polymerases . I . Primary structure of the EcoRI-C fragment of the Salmonella typhimurium gene rpoB}; Sverdlov ED et al.; BglII fragment of S . typhimurium DNA, containing rpoB gene coding for the RNA polymerase beta-subunit, was cloned . The nucleotide sequence of the rpoB gene EcoRI-C fragment (2873 b.p.) was determined.

J Antimicrob Chemother, 1986 May, 17(5), 559 - 69
Transposable resistance to trimethoprim and 0/129 in Vibrio cholerae; Goldstein F et al.; Vibrio cholerae biotype el tor strain BM2508, resistant to trimethoprim, 0/129, streptomycin and spectinomycin was isolated from the faeces of a child with severe diarrhoea . Resistance to trimethoprim and 0/129 was due to a dihydrofolate reductase type I and resistance to streptomycin-spectinomycin to a 3'',9-aminoglycoside-aminocyclitol adenylyltransferase . The resistance genes were not transferable to Escherichia coli and, as inferred from ultracentrifugation in cesium chloride-ethidium bromide and agarose gel electrophoresis of crude bacterial lysates, were located on the chromosome . The resistance genes were transposed to multiple sites of plasmids belonging to incompatibility groups 6-C and P, introduced in BM2508 and were subsequently transferred to E . coli (rec-), Salmonella typhimurium, V . cholerae and V . parahaemolyticus strains where they re-transposed into the chromosome . Analysis of plasmid DNA from the transconjugants by agarose gel electrophoresis following digestion with HindIII and by Southern hybridization using a ColEl::Tn7 probe indicated the presence of a 14-kilobase transposon, Tn1527, closely related to Tn7 . The emergence of Tn1527 in V . cholerae may lead to prophylactic and therapeutic failures due to trimethoprim resistance and to bacterial misidentification because of cross resistance to 0/129.

J Bacteriol, 1986 May, 166(2), 666 - 9
Phosphate starvation regulon of Salmonella typhimurium; Foster JW et al.; Several phosphate-starvation-inducible (psi) genetic loci in Salmonella typhimurium were identified by fusing the lacZ gene to psi promoters by using the Mu d1 and Mu d1-8 bacteriophages . Although several different starvation conditions were examined, the psi loci responded solely to phosphate deprivation . A regulatory locus, psiR, was identified as controlling the psiC locus . The psiR locus did not affect the expression of the Escherichia coli phoA locus or any of the other psi loci described.

J Bacteriol, 1986 May, 166(2), 651 - 7
Cloning and analysis of the sfrB (sex factor repression) gene of Escherichia coli K-12; Rehemtulla A et al.; The sfrB gene of Escherichia coli K-12 and the rfaH gene of Salmonella typhimurium LT2 are homologous, controlling expression of the tra operon of F and the rfa genes for lipopolysaccharide synthesis . We have determined a restriction map of the 19-kilobase ColE1 plasmid pLC14-28 which carries the sfrB gene of E . coli . After partial Sau3A digestion of pLC14-28, we cloned a 2.5-kilobase DNA fragment into the BamHI site of pBR322 to form pKZ17 . pKZ17 complemented mutants of the sfrB gene of E . coli and the rfaH gene of S . typhimurium for defects of both the F tra operon and the rfa genes . pKZ17 in minicells determines an 18-kilodalton protein not determined by pBR322 . A Tn5 insertion into the sfrB gene causes loss of complementing activity and loss of the 18-kilodalton protein in minicells, indicating that this protein is the sfrB gene product . These data indicate that the sfrB gene product is a regulatory element, since the single gene product elicits the expression of genes for many products for F expression and lipopolysaccharide synthesis.

J Natl Cancer Inst, 1986 May, 76(5), 879 - 83
Kinetics of depression and recovery of murine hepatic cytochrome P-450 levels after treatment with the interferon inducer polyriboinosinic-polyribocytidylic acid; Crowe DO et al.; In vivo treatment of randombred Swiss Webster mice with polyriboinosinic-polyribocytidylic acid (poly l X poly C) inhibited the induction of cytochrome P-450's by both 3-methylcholanthrene {(MCA) CAS: 56-49-5} and phenobarbitol {(PB) CAS: 50-06-6} . Concomitant treatments with poly l X poly C and a single dose of MCA inhibited the induction of P-450's for 24 hours and delayed the obtainment of the MCA-induced P-450 levels for approximately 48-72 hours . When cytochrome P-450 levels were induced by four successive daily treatments of MCA or PB and when poly l X poly C was given on only the 1st day, induction of P-450's was completely suppressed for 24 hours and obtainment of the maximal P-450 level was delayed by 72-96 hours . Treatment with poly l X poly C of animals preinduced for P-450's by four successive daily treatments with either PB or MCA decreased the P-450 content to the noninduced basal level within 24 hours . The effect was temporary in the MCA-treated mice since P-450 content recovered to the MCA-preinduced levels within 72 hours . PB-dependent P-450 induction was short lived, and no recovery occurred after poly l X poly C treatment of PB-preinduced mice . Reduced hepatic cytochrome P-450 contents correlated with decreased abilities of liver homogenates to metabolically activate benzo {a}pyrene (CAS: 50-32-8) and N-acetyl-2-aminofluorene (CAS: 53-96-3), as scored in an Ames Salmonella typhimurium revertant assay.

Mutat Res, 1986 May, 160(3), 249 - 57
Studies of mutagenicity and clastogenicity of 5-azacytidine in human lymphoblasts and Salmonella typhimurium; Call KM et al.; 5-Azacytidine (5-AzaC) induced mutation in the TK+/- human lymphoblastoid line, TK6, at both the thymidine kinase (tk) locus as measured by resistance to trifluorothymidine (F3TdR), and the hypoxanthine-guanine phosphoribosyltransferase (hgprt) locus, as measured by resistance to 6-thioguanine (6TG) . F3TdRR and 6TGR mutant fractions induced by 5-AzaC were observed after a normal phenotypic expression time and remained stable . Interestingly, 5-AzaC was 5-10 times more mutagenic at the tk locus than the hgprt locus . However, F3TdRR colonies from 5-AzaC-treated cultures behaved like TK-deficient mutants induced by other chemical mutagens . The TK or HGPRT phenotype had no effect on the toxicity of 5-AzaC, thus eliminating differential toxicity as a potential cause for the observed higher mutability at the tk locus . 5-AzaC did not induce F3TdRR cells in the parental TK+/+ lymphoblastoid line, indicating that 5-AzaC-induced F3TdRR variants were not due to a dominant alteration in gene expression . 5-AzaC did not induce chromosomal aberrations in TK6 cells, eliminating clastogenic events as a potential cause for the higher mutability at the tk locus . 5-AzaC was also found to be mutagenic in a forward mutation assay to 8-azaguanine resistance in Salmonella typhimurium.

Biochem Biophys Res Commun, 1986 Apr 29, 136(2), 577 - 81
Tetrathionate reductase of Salmonella thyphimurium: a molybdenum containing enzyme; Hinojosa-Leon M et al.; Use of radioactive molybdenum demonstrates that the tetrathionate reductase of Salmonella typhimurium is a molydenum containing enzyme . It is proposed that this enzyme shares with other molybdo-proteins, such as nitrate reductase, a common molybdenum containing cofactor the defect of which leads to the loss of the tetrathionate reductase and nitrate reductase activities.

Biochemistry, 1986 Apr 22, 25(8), 2198 - 205
Conformation of d(CpG) modified by the carcinogen 4-aminobiphenyl: a combined experimental and theoretical analysis; Shapiro R et al.; The change in DNA conformation produced by the attachment of a reactive substance is likely to be a vital factor in determining the biological consequences of the reaction . We have prepared a deoxydinucleoside monophosphate containing the major adduct derived from the carcinogenic amine 4-aminobiphenyl and analyzed its conformation by theoretical and experimental methods . Reaction of d(CpG) with N-acetoxy-N-(trifluoroacetyl)-4-aminobiphenyl afforded the product modified at C-8 of guanine with 4-aminobiphenyl . After purification by reverse-phase high-performance liquid chromatography, milligram amounts of product were obtained . It was analyzed by circular dichroism, proton magnetic resonance, and minimized potential-energy calculations . A flexible molecule with a mixture of conformers is indicated . Both carcinogen-base-stacked states and base-base-stacked states, with guanine both syn anti, contribute to the population mixture on the dimer level . The global minimum-energy conformation has syn-guanine and carcinogen-base stacking . Forms of this type are calculated to represent roughly 58% of the conformer population . Because of the twisted nature of the biphenyl moiety, carcinogen-base stacking inherently involves less overlap than that in the planar and rigid three-ringed aminofluorene analogue . This difference might relate to the diminished effectiveness of the aminobiphenyl vs . the aminofluorene adduct as a frameshift mutagen in Salmonella typhimurium 1538.

J Am Vet Med Assoc, 1986 Apr 15, 188(8), 876 - 8
Immunoglobulin A myeloma in a cat with pleural effusion and serum hyperviscosity; Hawkins EC et al.; Immunoglobulin A myeloma, serum hyperviscosity, and septic pleuritis were diagnosed in a cat with pleural and peritoneal effusions . Serum hyperviscosity was determined by use of a WBC pipette, and clinical manifestations included retinopathy and cardiac changes . The presence of Salmonella typhimurium in the pleural fluid may have resulted from increased susceptibility to infection . Postmortem examination revealed plasma cell infiltration of the pleura, mesenteric lymph nodes, and the serosa of the intestine, liver, and spleen . This case represents an unusual form of myeloma in the cat.

Biochem J, 1986 Apr 15, 235(2), 385 - 90
Quantification of tissue-type plasminogen activator (t-PA) mRNA in human endothelial-cell cultures by hybridization with a t-PA cDNA probe; van Zonneveld AJ et al.; We describe the construction of a recombinant DNA plasmid, consisting of the vector pBR322 and full-length tissue-type plasminogen-activator (t-PA) cDNA, by using polyadenylated RNA from cultured Bowes melanoma cells as substrate . A 1280-base-pair PstI restriction fragment, covering the 3' untranslated region and part of the coding region for the t-PA L-chain, was used as a radiolabelled probe to determine the size and the number of t-PA mRNA molecules in cultured endothelial cells of different origin from the same individual . Northern blotting showed that in all these cells a t-PA mRNA is synthesized of about 2500 nucleotides, indicating that transcriptional initiation, splicing and polyadenylation is similar . The number of t-PA mRNA molecules per cell measured, by using a dot-blotting technique and t-PA mRNA made in vitro, with a plasmid DNA preparation harbouring a specific promotor of the Salmonella typhimurium bacteriophage SP6, t-PA cDNA and SP6 RNA polymerase as standard, is approx . 10,000 in all cultured endothelial cells from adult vessels . However, the amount of t-PA antigen synthesized and/or secreted differs by a factor of 6-20 . Relatively large amounts of t-PA antigen secreted were detected in conditioned medium from vena-cava-derived cells, whereas low amounts were found in conditioned medium from arteria-iliaca-derived cells.

J Appl Toxicol, 1986 Apr, 6(2), 101 - 8
Effect of donor age on the levels of activity of rat, hamster and human liver S9 preparations in the Salmonella mutagenicity assay; Raineri R et al.; Liver S9 fractions were prepared from male and female Syrian Golden hamsters and Sprague-Dawley rats, 1, 3, 6 and 12 months of age, which were either uninduced (corn-oil treated) or induced with Aroclor 1254 suspended in corn oil . These preparations were compared at varying protein levels for their ability to metabolize polycyclic aromatic hydrocarbons (benzo(a)pyrene, 3-methylcholanthrene, 7,12-dimethylbenzanthracene), aromatic amines (N-2-acetyl-aminofluorene, beta-naphthylamine, benzidine), and nitroso compounds (N-nitroso-diethylamine, nitrosopyrrolidine, nitrosodiethylmethylurea) to products mutagenic to Salmonella typhimurium . With 3-methylcholanthrene or benzo(a)pyrene in the presence of S9 preparations from Aroclor-treated male rats, the numbers of revertant colonies decreased with increasing age of the animals . Mutagenicity of aromatic amines was not affected by the age of the donor animals from which the S9 was prepared . The use of liver S9 from 1-month-old hamsters produced the highest number of revertant colonies with nitrosodiethylamine . This number decreased with preparations from animals of increasing age . The greatest number of revertant colonies with nitrosopyrrolidine occurred with preparations from male hamsters . A decrease in numbers of revertant colonies with increasing age was observed with the S9 preparation from Arcolor-treated male rats . Nitroso-diethylmethylurea was mutagenic only in the presence of S9 from male or female Aroclor-treated hamsters and the metabolic activity of the S9 preparations did not change with age . S9 preparations from livers of 50-70-year-old humans were compared for their ability to produce mutagenic metabolites at a number of protein levels.(ABSTRACT TRUNCATED AT 250 WORDS)

J Gen Microbiol, 1986 Apr, 132 ( Pt 4), 1035 - 41
Characterization of SE1, a new general transducing phage of Salmonella typhimurium; Llagostera M et al.; A transducing phage, SE1, which is able to infect Salmonella typhimurium was isolated from a Salmonella enteritidis strain . SE1 is a temperate phage which is heteroimmune with respect to phages P22, L, KB1 and ES18 . It is similar in morphology and size to phages P22, L and KB1 and is serologically related to phages P22 and L but not to KB1 . Efficiencies of generalized transduction effected by phage SE1 are similar to those for P22HT (int7), a mutant which mediates a high frequency of chromosomal gene transduction . The lengths of chromosomal DNA transduced by SE1 and P22HT (int7) are similar . Furthermore, the SE1 prophage does not exclude the transducing particles from cells it has lysogenized; consequently it is possible to use both SE1 lysogens and non-lysogenic strains as recipients in SE1-mediated transduction experiments, and obtain similar transduction efficiencies . However, the SE1 prophage gives rise to a lysogenic conversion that decreases the rate of adsorption of SE1 and L phages by about 50%, but does not affect adsorption of P22 . Altogether these results suggest that phage SE1 may be a useful tool in the genetic manipulation of S . typhimurium.

Can J Vet Res, 1986 Apr, 50(2), 165 - 73
Galactose epimeraseless mutants of Salmonella typhimurium as live vaccines for calves; Clarke RC et al.; The purpose of the study was to evaluate the safety and efficacy of a galactose epimeraseless mutant of Salmonella typhimurium administered as an oral vaccine to one week old calves and to investigate properties of galactose epimeraseless mutants which affect their virulence and immunogenicity . The galactose epimeraseless mutant S . typhimurium strain G30D caused diarrhea and fever in three calves to which it was administered orally at a dose of 10(10) organisms; all three calves died following challenge with virulent S . typhimurium ten days postvaccination . Mild illness developed in four calves vaccinated with a dose of 9 X 10(6) organisms and one of these calves survived challenge . Three unvaccinated calves died following challenge . The vaccine organism persisted in tissues and was shed for a prolonged period by calves which received 10(10) organisms . Studies of characteristics of galactose epimeraseless mutants of S . typhimurium showed that, in the presence of galactose, there is selection for secondary mutants which are galactose resistant . The studies indicate that galactose epimeraseless mutants of S . typhimurium are not good candidate live vaccine organisms for use in calves.

Avian Dis, 1986 Apr-Jun, 30(2), 313 - 8
Effects of cage contamination with coccidia and salmonella on acute salmonellosis in young chickens; Kosugi Y et al.; The effects of concurrent cage contamination with Salmonella typhimurium and Eimeria tenella on the establishment of salmonella infection in day-old chickens were investigated . Chickens were divided into five groups: uninfected recipient birds placed in a cage contaminated by donor birds infected with E . tenella and S . typhimurium; E . tenella-infected recipients placed in a cage contaminated by S . typhimurium-infected donors; uninfected recipients placed in a cage contaminated by S . typhimurium-infected donors; E . tenella-infected recipients placed in a cage contaminated by uninfected donors; and uninfected recipients placed in a cage contaminated by uninfected donors . Three identical trials were conducted . Recipient birds were necropsied 4, 7, and 11 days after caging . In the cage where donor birds infected with both organisms had been reared, S . typhimurium counts in feces and number of feces positive for S . typhimurium were significantly (P less than 0.05) greater than those in the other cages on days 0, 4, and 7 after caging . Moreover, in this cage, more chicks died, counts of S . typhimurium in cecal contents were greater, and more birds were positive for S . typhimurium than in the other groups . This suggests that S . typhimurium infection in day-old chickens is enhanced in cages contaminated with E . tenella and S . typhimurium compared with infection in cages contaminated with S . typhimurium alone.

Chem Biol Interact, 1986 Apr, 58(1), 69 - 78
Relationships between structure of 5-nitro-2-furylethylenes and their SOS-function-inducing activities in Escherichia coli; Sturdik E et al.; The SOS-function-inducing activities of 36 furylethylenes were characterized in Escherichia coli K12 . The induction of the SOS function was assayed by monitoring the beta-galactosidase activity in the sulA::lacZ fusion strain PQ 37 . To correct for the inhibitory effects of test compounds on mRNA or protein synthesis, the level of the constitutive alkaline phosphatase was assayed in parallel . Tested furylethylenes included nine alkylesters and eleven N-alkylamides of 5-nitro-2-furylacrylic acid (NFAA) and fourteen derivatives differing not only in substituents at exocyclic double bond, but also in the position 5 of the furan ring . The induction of the SOS-function by the derivatives depends on the presence of 5-nitrofuran centre in their molecule; side chains in the position 2 modify the degree of SOS response . SOS-inducing potency of n-alkyl congeners decreases with increasing lipophilicity . Effect of derivatives with branched alkyl substituents is lower than expected from the behavior of the n-alkyl homologues . All derivatives with positive effect on SOS-function in E . coli show mutagenic activity on Salmonella typhimurium TA98 in Ames test.

J Hyg (Lond), 1986 Apr, 96(2), 161 - 9
Inhibition of colonization of the chicken caecum with Salmonella typhimurium by pre-treatment with strains of Escherichia coli; Barrow PA et al.; Simultaneous oral administration of broth cultures of three strains of Escherichia coli isolated from sewage and an abattoir strongly inhibited the colonization of a subsequently administered strain of Salmonella typhimurium . The three strains were protective against the S . typhimurium strain under a variety of conditions: in different breeds and in chickens fed different diets . The strains were not equally effective against other salmonella strains . Oral administration of the strains produced a statistically significant reduction in the excretion of the S . typhimurium strain over a period of 7 weeks.

Cancer Lett, 1986 Apr, 31(1), 27 - 34
Mechanism of inhibition of N-methyl-N'-nitro-N-nitrosoguanidine-induced mutagenesis by phenolic compounds; Chan RI et al.; At non-toxic concentrations, 2 naturally occurring phenolic compounds, caffeic acid and chlorogenic acid, suppressed the mutagenic activity of the carcinogen N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) in Salmonella typhimurium strain TA1535 . The inhibitory effect was observed only when the phenolic compound and the mutagen were administered concurrently . The interaction between phenolic compounds and MNNG was also studied in a cell-free system using a colorimetric method . The results are consistent with the assumption that phenolic compounds scavenge reactive electrophilic MNNG degradation products, thereby preventing their action on critical cellular targets.

J Bacteriol, 1986 Apr, 166(1), 341 - 5
Escherichia coli B/r leuK mutant lacking pseudouridine synthase I activity; Searles LL et al.; Escherichia coli B/r strain EB146 containing mutation leuK16 has elevated levels of enzymes involved in the synthesis of leucine, valine, isoleucine, histidine, and tryptophan (Brown et al., J . Bacteriol . 135:542-550, 1978) . We show here that strain EB146 (leuK16) has properties that are similar to those of E . coli and Salmonella typhimurium hisT strains . In tRNA1Leu from both hisT and leuK strains, positions 39 and 41 are uridine residues rather than pseudouridine residues . Furthermore, in tRNA3Leu and tRNA4Leu from a leuK strain, uridine residues at positions 39 and 40, respectively, are unmodified . Pseudouridine synthase I activity is missing in extracts of strain EB146 (leuK16), and extracts of strain EB146 (leuK16) and of a hisT strain do not complement one another in vitro . Four phenotypes of strain EB146 (leuK16), leucine excretion, wrinkled colony morphology, and elevated levels of leu and his enzymes, are complemented by a plasmid having a 1.65-kilobase DNA fragment containing the E . coli K-12 hisT locus . These results indicate that either leuK codes for pseudouridine synthase I (and is thus a hisT locus in reality) or, less likely, it codes for a product that affects the synthesis or activity of pseudouridine synthase I.

J Bacteriol, 1986 Apr, 166(1), 253 - 9
Proline transport and osmotic stress response in Escherichia coli K-12; Grothe S et al.; Proline is accumulated in Escherichia coli via two active transport systems, proline porter I (PPI) and PPII . In our experiments, PPI was insensitive to catabolite repression and was reduced in activity twofold when bacteria were subjected to amino acid-limited growth . PPII, which has a lower affinity for proline than PPI, was induced by tryptophan-limited growth . PPII activity was elevated in bacteria that were subjected to osmotic stress during growth or the transport measurement . Neither PPI nor uptake of serine or glutamine was affected by osmotic stress . Mutation proU205, which was similar in genetic map location and phenotype to other proU mutations isolated in E . coli and Salmonella typhimurium, influenced the sensitivity of the bacteria to the toxic proline analogs azetidine-2-carboxylate and 3,4-dehydroproline, the proline requirements of auxotrophs, and the osmoprotective effect of proline . This mutation did not influence proline uptake via PPI or PPII . A very low uptake activity (6% of the PPII activity) observed in osmotically stressed bacteria lacking PPI and PPII was not observed when the proU205 lesion was introduced.

Infect Immun, 1986 Apr, 52(1), 6 - 11
Early-phase endotoxin tolerance: induction by a detoxified lipid A derivative, monophosphoryl lipid A; Madonna GS et al.; After a sublethal exposure to lipopolysaccharide (LPS) or to lipid A, which is that portion of the LPS molecule associated with endotoxicity, a transient period ensues during which a normally responsive individual is rendered hyporesponsive to LPS-induced toxicity . This period has been defined as early-phase endotoxin tolerance . Recently, a nontoxic derivative of lipid A from Salmonella typhimurium, monophosphoryl lipid A (MPL), was isolated and purified . In this study, we assessed the ability of MPL to induce early endotoxin tolerance . Initial injection of MPL resulted in a dose-dependent stimulation of both serum colony-stimulating factor and serum interferon, indicators of in vivo LPS responsiveness . In contrast, MPL failed to induce the symptoms of endotoxicity which are normally seen after injection of even sublethal amounts of intact endotoxin or lipid A preparations . Injection of MPL on day 0 reduced significantly the amount of LPS-induced serum colony-stimulating factor and interferon produced upon challenge with Escherichia coli LPS 3 days later and also mitigated toxic manifestations, as evidenced by a marked increase in the 50% lethal dose . Like the early tolerance induced by wild-type (toxic) LPS, MPL-induced tolerance was characterized by an accompanying elevation in the number of bone marrow-derived macrophage progenitor cells and by an alteration in bone marrow cell sizing profiles . These results indicate that MPL is effective in inducing a state of LPS-hyporesponsiveness without the toxic side effects of endotoxin and that the structural component(s) necessary for induction of early-phase endotoxin tolerance is contained within MPL.

Proc Soc Exp Biol Med, 1986 Apr, 181(4), 560 - 8
Genetic variation in the recruitment and activation of chicken peritoneal macrophages; Qureshi MA et al.; Genetic variation in the ability to recruit and activate peritoneal macrophages was examined in seven partially developed 15I5-B congenic White Leghorn chicken lines . While the ability to generate peritoneal exudate cells (PECs) was similar in all lines, major differences were observed in the numbers, composition, and functional activity of harvestable peritoneal adherent cell populations . In response to a general stimulant, Sephadex, lines .7-2 and .6-2 produced the greatest numbers of adherent peritoneal cells while lines .C-12 and .15I-5 were among the poorest responders . Macrophage percentage of adherent PECs varied between lines . 15I5 chickens produced a consistently high percentage of adherent macrophages while .6-2 birds exhibited the lowest macrophage percentage at all ages examined . Phagocytosis was used as one measure of the level of macrophage activation and similar results were obtained using both opsonized and unopsonized sheep erythrocytes; adherent peritoneal cells from lines .6-2, .7-2, and .P-13 exhibited the highest activity and .C-12, .15I-5, and background 15I5(B15) lines produced cells with the lowest phagocytic activity . In a second functional assay, the killing of Salmonella typhimurium, macrophage-rich cells from line .P-13 exhibited the lowest activity which was significantly lower than that obtained with cells from lines .6-2 and .15I-5 . Antigen-specific stimulation of peritoneal adherent cells by ferritin also showed that .C-12 was a low responder in contrast with other lines . The results indicate that these genetic lines differ in peritoneal macrophage function and suggest that the chicken major histocompatibility complex may influence certain properties of chicken macrophage function.

Carcinogenesis, 1986 Apr, 7(4), 673 - 6
Effects of 6-nitro substitution on 5-methylchrysene tumorigenicity, mutagenicity and metabolism; el-Bayoumy K et al.; 6-Nitro-5-methylchrysene was prepared by nitration of 5-methylchrysene and the mutagenic and tumorigenic activities of the two compounds were compared . Whereas 5-methylchrysene was a strong tumor initiator on mouse skin, no tumors were observed in the mice treated with 6-nitro-5-methylchrysene . In Salmonella typhimurium TA100, both compounds were mutagenic in the presence, but not in the absence, of rat liver 9000 g supernatant . The major metabolite of 6-nitro-5-methylchrysene in rat liver in vitro was trans-1,2-dihydro-1,2-dihydroxy-6-nitro-5-methylchrysene . In view of the ready conversion of 6-nitro-5-methylchrysene to a 1,2-dihydrodiol, its apparent lack of tumorigenicity in mouse skin was intriguing.

Microb Pathog, 1986 Apr, 1(2), 115 - 24
Genetic mapping of novel virulence determinants of Salmonella typhimurium to the region between trpD and supD; Benjamin WH Jr et al.; Salmonella typhimurium strains are known to vary greatly in their virulence for mice . A few of the genes affecting their virulence have been described . In this report we have localized at least two genes that affect the ability of S . typhimurium to grow in BALB/cByJ to a 6 unit section of the salmonella chromosome which does not contain any previously described virulence determinants . The genetic mapping was done by interrupted matings using Hfr strains made in a virulent LT2 strain . The Hfr strains were constructed by inserted the plasmid F'(TS)114 lac+ Tn::10 into the LT2 chromosome at specific sites through homologous recombination with chromosomal Tn10s . Short interrupted matings to an avirulent LT2 strain in either direction through the portion of the chromosome from trpD at 34 units to supD at 40 units resulted in transconjugants which were fully virulent . Since we also found several transconjugants with intermediate virulence it appears that more than one virulence gene may exist in this area of the chromosome . The mechanisms of action of these genes are not known.

J Bacteriol, 1986 Apr, 166(1), 1 - 8
An ethA mutation in Bacillus subtilis 168 permits induction of sporulation by ethionine and increases DNA modification of bacteriophage phi 105; Allen ER et al.; In contrast to Escherichia coli and Salmonella typhimurium, Bacillus subtilis could convert ethionine to S-adenosylethionine (SAE), as can Saccharomyces cerevisiae . This conversion was essential for growth inhibition by ethionine because metE mutants which were deficient in S-adenosylmethionine synthetase activity, were resistant to 10 mM ethionine and converted only a small amount of ethionine to SAE . Another mutation (ethA1) produced partial resistance to ethionine (2 mM) and enabled continual sporulation in glucose medium containing 4 mM DL-ethionine . This sporulation induction probably resulted from the effect of SAE, since it was abolished by the addition of a metE1 mutation . The induction of sporulation was not simply controlled by the ratio of SAE to S-adenosylmethionine, but apparently depended on another effect of the ethA1 mutation, which could be demonstrated by comparing the restriction of clear plaque mutants of bacteriophage phi 105 grown in an ethA1 strain with the restriction of those grown in the standard strain . The phages grown in the ethA1 strain showed increased protection against BsuR restriction . We propose that SAE induces sporulation through the inhibition of a key methylation reaction.

Am J Vet Res, 1986 Apr, 47(4), 769 - 73
Enterotoxin activity of a Salmonella typhimurium of equine origin in vivo in rabbits and the effect of Salmonella culture lysates and cholera toxin on equine colonic mucosa in vitro; Murray MJ; To determine whether a strain of Salmonella typhimurium (UCD 1755) of equine origin had enterotoxin activity, 2 ml of a cell-free culture lysate of strain UCD 1755 and approximately 10(9) viable strain UCD 1755 organisms were inoculated into ligated small intestinal segments of rabbits . Intestinal segments inoculated with viable strain UCD 1755 organisms and those inoculated with a cell-free culture lysate of strain UCD 1755 had significant (P less than 0.05) accumulations of fluid 10 hours after inoculation when compared with ligated intestinal segments either inoculated with sterile brain-heart infusion broth or left empty . There was not a statistically significant difference between fluid accumulation of intestinal segments inoculated with viable strain UCD 1755 and that of segments inoculated with a cell-free culture lysate of strain UCD 1755 . The responses of equine colonic mucosa to culture filtrates of 2 strains of salmonella typhimurium (UCD 1755 and SL 1027) and purified cholera toxin were studied in vitro . Isolated smaples of colonic mucosa were incubated for 4 hours at 37 C in Krebs-Henseleit bicarbonate buffer (KHB) alone, KHB plus culture lysate of strain UCD 1755, KHB plus culture lysate of strain SL 1027, and KHB plus 1 microgram of cholera toxin/ml . Cyclic adenosine monophosphate (cAMP) content of each sample was determined.(ABSTRACT TRUNCATED AT 250 WORDS)

J Bacteriol, 1986 Apr, 166(1), 275 - 80
Inversion of aerotactic response in Escherichia coli deficient in cheB protein methylesterase; Dang CV et al.; Mutants of Escherichia coli and Salmonella typhimurium that were deficient in protein methylesterase activity encoded by cheB had an inverted response to oxygen; they were repelled by concentrations of oxygen that attract wild-type bacteria . Normal responses to oxygen and phosphotransferase substrates were observed in mutants that were deficient in protein methyltransferase (CheR) and the methyl-accepting transducing proteins (Tsr, Tar, Trg) . However, the methylation-independent response to oxygen was modified by the loss of esterase activity . The inversion was apparently effected by the amidated Tsr protein present in cheB tsr+ mutants because aerotaxis was normal in cheB tsr strains . Chemotaxis to phosphotransferase sugars was normal in cheB mutants provided the extreme clockwise bias of the flagellar motors was modified to increase the probability of counterclockwise rotation.

J Bacteriol, 1986 Apr, 166(1), 187 - 93
Subdivision of flagellar genes of Salmonella typhimurium into regions responsible for assembly, rotation, and switching; Yamaguchi S et al.; Three flagellar genes of Salmonella typhimurium (flaAII.2, flaQ, and flaN) were found to be multifunctional, each being associated with four distinct mutant phenotypes: nonflagellate (Fla-), paralyzed (Mot-), nonchemotactic (Che-) with clockwise motor bias, and nonchemotactic (Che-) with counterclockwise motor bias . The distribution of Fla, Mot, and Che mutational sites within each gene was examined . Fla sites were fairly broadly distributed, whereas Mot and Che sites were more narrowly defined . Local subregions rich in sites of one type were not generally rich in sites of another type . Among Che sites, there was little overlap between those corresponding to a clockwise bias and those corresponding to a counterclockwise bias . Our results suggest that within the corresponding gene products there are specialized subregions for flagellar structure, motor rotation, and control of the sense of rotation.

Infect Immun, 1986 Apr, 52(1), 101 - 9
In vivo repackaging of recombinant cosmid molecules for analyses of Salmonella typhimurium, Streptococcus mutans, and mycobacterial genomic libraries; Jacobs WR et al.; Strains of Escherichia coli K-12 were constructed that permitted the amplification of in vitro-packaged recombinant cosmid-transducing particles by in vivo repackaging of recombinant cosmid molecules . Thermal induction of these thermoinducible, excision-defective lysogens containing recombinant cosmid molecules yielded high titers of packaged recombinant cosmids and low levels of PFU . These strains were used to amplify packaged recombinant cosmid libraries of Mycobacterium leprae, Mycobacterium vaccae, Salmonella typhimurium, and Streptococcus mutans DNA . Contiguous and noncontiguous libraries were compared for the successful identification of cloned genes . Construction of noncontiguous libraries allowed the dissociation of desired genes from genes that were deleterious to the survival of a cosmid recombinant and permitted selection for unlinked traits that resulted in a selected phenotype . In vivo repackaging of recombinant cosmids permitted amplification of the original in vitro-packaged collection of transducing particles, storage of cosmid libraries as phage lysates, facilitation of complementation screening, expression analysis of repackaged recombinant cosmids after UV-irradiated cells were infected, in situ enzyme or immunological screening, and facilitation of recovery of recombinant cosmid molecules containing transposon inserts.

Biochem Genet, 1986 Apr, 24(3-4), 195 - 205
Biochemical and genetic characterization of L-glutamate transport and utilization in Salmonella typhimurium LT-2 mutants; Alvarez-Jacobs J et al.; Two systems for L-glutamate transport were found in Salmonella typhimurium LT-2 GltU+ (glutamate utilization) mutants . The first one is similar to the glt system previously described in Escherichia coli; by transductional analysis the structural gene, gltS, coding for the transport protein was located at minute 80 of the chromosome as part of the operon gltC-gltS, and its regulator, the gltR gene, near minute 90; the gltS gene product transports both L-glutamate and L-aspartate, is sodium independent, and is beta-hydroxyaspartate sensitive . The second transport system, whose structural gene was called gltF and is located at minute 0, was L-glutamate specific, sodium independent, and alpha-methylglutamate sensitive . Two aspartase activities occurred in S . typhimurium LT-2: the first one was present only in the GltU+ mutants, had a pH 6.4 optimum, was essential for both L-glutamate and L-aspartate metabolism, and mapped at minute 94, close to the ampC gene . The second one had a pH 7.2 optimum, could be induced by several amino acids, and thus may have a general role in nitrogen metabolism.

Infect Immun, 1986 Apr, 52(1), 344 - 7
In vivo properties of a cloned K88 adherence antigen determinant; Dougan G et al.; An Escherichia coli strain of serotype O9:K36:H19 harboring the K88 recombinant plasmid pMK005 was able to efficiently colonize the small bowel of young piglets after oral infection . The strain expressed K88 antigen in vivo, and bacteria were detected in close association with the surface of the intestinal villi . Mice infected orally or intravenously with attenuated Salmonella typhimurium SL3261 harboring pMK005 were well protected against subsequent challenge with the highly virulent S . typhimurium SL1344 . Anti-K88 antibodies were detected in the serum of mice immunized with SL3261(pMK005).

Eur J Clin Microbiol, 1986 Apr, 5(2), 148 - 51
Cross-reactivity of monoclonal antibodies against lipopolysaccharides of gram-negative bacteria; de Jongh-Leuvenink J et al.; Monoclonal antibodies were produced against Escherichia coli O111, Escherichia coli J5, and the rough (R) mutant of Salmonella typhimurium M206, and tested by enzyme-linked immunosorbent assay against lipopolysaccharides of several gram-negative strains . The monoclonal antibodies were also identified with an immunoblotting assay . Anti-Escherichia coli O111 monoclonal antibodies reacted only with homologous O antigens . Anti-J5 monoclonal antibodies cross-reacted with core lipopolysaccharide, especially with Rc lipopolysaccharide . IgM anti-J5 monoclonal antibodies showed more extensive cross-reactivity than IgG3 monoclonal antibodies . Anti-Re monoclonal antibodies cross-reacted weakly with all rough lipopolysaccharide tested . Thus, the varying specificity of these monoclonal antibodies seems to indicate that the core regions in the lipopolysaccharides of various gram-negative bacteria are not similar.

Mol Gen Genet, 1986 Apr, 203(1), 172 - 6
Cloning part of the region encoding biosynthetic enzymes for surface antigen (O-antigen) of Salmonella typhimurium; Brahmbhatt HN et al.; The rfb gene cluster of Salmonella typhimurium encodes the enzymes required for the biosynthesis of the O-Antigen . A part of it has been cloned in plasmid vectors pBR322 and pUC9 using an adjacent, previously cloned, part of the his operon (Barnes 1981) as a molecular probe for the first clone . A detailed restriction enzyme map of 7.57 kb of rfb DNA is presented and the approximate locations of two of the genes, rfbK and rfbM have been defined.

Biochim Biophys Acta, 1986 Mar 28, 870(2), 357 - 66
Inactivation of glucosamine-6-phosphate synthetase from Salmonella typhimurium LT2 by fumaroyl diaminopropanoic acid derivatives, a novel group of glutamine analogs; Chmara H et al.; A novel group of glutamine analogs, N3-fumaroyl-L-2,3-diaminopropanoic acid (FDP) and its derivatives and analogs including amide (FCDP), methyl ester (FMDP) and its homologue, N4-(4-methoxyfumaroyl)-L-2,4-diaminobutanoic acid, inactivate glucosamine-6-phosphate synthetase (L-glutamine: D-fructose-6-phosphate aminotransferase (hexose-isomerizing), EC 2.6.1.16), isolated from Salmonella typhimurium, by covalent modification . For comparative purposes, selected known glutamine analogs were also examined . Anticapsin, 6-diazo-5-oxo-L-norleucine and, at high concentration, azaserine inactivate the enzyme . The pseudo-first-order rate constants show a hyperbolic dependence on inhibitor concentration for all the above-mentioned inhibitors, suggesting the formation of a reversible complex prior to covalent modification . Dissociation constants for inhibitors were determined and ranged from 10(-4) M for FCDP to 10(-6) M for FMDP . Albizziin, gamma-glutamylhydroxamate and, at low concentration, azaserine inhibit glucosamine synthetase only reversibly . All inhibitors tested are competitive in relation to glutamine . and competitive inhibitors, albizziin and gamma-glutamylhydroxamate protect the enzyme against inactivation . Fructose 6-phosphate accelerates the rate of inactivation . Some analogs of FDP, such as SMDP, CRDP, O-FMSer, MMDP and AADP, are not active against glucosamine-6-phosphate synthetase . The structure-activity relationship of the novel group of glutamine analogs is discussed and structural requirements for the activity of these compounds is established . It is postulated that the compounds examined can be classified as mechanism-based enzyme inactivators.

Biochemistry, 1986 Mar 25, 25(6), 1346 - 54
Evidence for the existence of a channel in the glucose-specific carrier EIIGlc of the Salmonella typhimurium phosphoenolpyruvate-dependent phosphotransferase system; Robillard GT et al.; The effect of membrane-impermeable sulfhydryl reagents on glucose-specific enzyme II (EIIGlc) activity has been studied in Salmonella typhimurium whole cells and in properly sealed inverted cytoplasmic membrane vesicles . Glutathione N-hexylmaleimide and N-polymethylenecarboxymaleimides inactivate methyl alpha-D-glucopyranoside (alpha-MeGlc) transport and phosphorylation in whole cell preparations at a dithiol that can be protected by oxidizing reagents, trivalent arsenicals, or phosphorylation of EIIGlc . Accessibility to this activity-linked site is restricted to small apolar reagents or to polar reagents with a hydrophobic spacer between the polar group and the reactive maleimide moiety . These same reagents inactivate alpha-MeGlc phosphorylation in inverted cytoplasmic membrane vesicles . Inhibition results from reaction at a dithiol that can be protected by nonpermeant mercurials, oxidants, and arsenicals as well as by phosphorylation of EII . The characteristics of this site are virtually identical with those of the activity-linked dithiol elucidated in intact cells . No evidence could be found for a second activity-linked site on the other side of the membrane when the permeable reagent N-ethylmaleimide was used . Since only one activity-linked dithiol can be detected with sealed inverted membrane vesicles or intact cells and it is accessible to membrane-impermeable sulfhydryl reagents from both sides of the cytoplasmic membrane, we suggest that it is located in a channel constructured by the carrier and that the channel spans the membrane . A second dithiol, not essential for activity, is located near the outer surface of the cytoplasmic membrane.

Nucleic Acids Res, 1986 Mar 25, 14(6), 2779 - 98
Analysis and comparison of the internal promoter, pE, of the ilvGMEDA operons from Escherichia coli K-12 and Salmonella typhimurium; Lopes JM et al.; It was previously determined that the distal portion of the ilvGMEDA operon was expressed despite the insertion of transposons into ilvG and ilvE . This observation suggested the existence of internal promoters upstream of ilvE (pE) and ilvD (pD) . The internal promoter pE, responsible for part of ilvEDA expression, has been analyzed both in vivo and in vitro . Our results indicate that: pE exists in both E . coli K-12 and S . typhimurium; pE is located in the distal end of the ilvM coding sequence; the pE sequence is highly conserved in the two bacteria; the amino acid sequence of the ilvM gene product is 93% homologous between the two bacteria; transcription from pE can be demonstrated both in vivo and in vitro; the efficiency of pE is essentially equivalent in the two bacteria.

J UOEH, 1986 Mar 20, 8 Suppl, 271 - 9
{Studies on the mutagenicity test methods: comparison of the screening methods using Salmonella typhimurium and Saccharomyces cerevisiae}; Fukunaga M et al.; Twenty-two acridine compounds and eleven phenanthridinium derivatives were tested for the induction of mutation in both eukaryotic, Saccharomyces cerevisiae and bacterial, Salmonella typhimurium . Summarized and discussed about the relationships between mutagenic activity and chemical structure of their compounds . Some metal compounds were examined for the induction of mitotic crossing over, mitotic gene conversion and reversion in yeast . Furthermore, the effects of the cell growth at the presence of these metal compounds on the mutations induced by nitrous acid was also examined . Mutagenic susceptibility of the yeast to these metal compounds on the comparison to the bacteria and the mechanisms of metal mutagenicity were discussed.

Antimicrob Agents Chemother, 1986 Mar, 29(3), 535 - 8
Differences in susceptibility to quinolones of outer membrane mutants of Salmonella typhimurium and Escherichia coli; Hirai K et al.; The mechanism of penetration of quinolones through the bacterial outer membrane was studied with lipopolysaccharide-deficient and porin-deficient mutants . The data indicated that the lipopolysaccharide layer might form a permeability barrier for hydrophobic quinolones such as nalidixic acid but not for hydrophilic quinolones such as norfloxacin and ciprofloxacin . The results also showed that quinolones with a low relative hydrophobicity appeared to permeate through OmpF porin, whereas quinolones with a low relative hydrophobicity appeared to permeate through OmpF porin, whereas quinolones with a high relative hydrophobicity appeared to permeate through both OmpF porin and phospholipid bilayers.

Toxicol Lett, 1986 Mar, 30(3), 209 - 17
Metabolism of 2-aminofluorene by rat small-intestine fractions: differential effect of intragastric versus intraperitoneal administration of 3-methylcholanthrene; Fouarge M; The influence of 3-methylcholanthrene (3-MC) induction on small intestinal enzymes was studied by measuring the enzymatic characteristics of 2-aminofluorene N-hydroxylase and the activation of this aromatic amine into mutagen(s) towards Salmonella typhimurium . When injected intraperitoneally to rats, 3-MC modified neither the N-hydroxylation nor the mutagenic properties of 2-aminofluorene (2-AF) in the presence of postmitochondrial and microsomal fractions from small intestine . On the other hand, the intragastric administration of the inducer slightly increased affinity and significantly induced maximum velocity of N-hydroxylase . Moreover, the ability of the small intestinal fractions to activate 2-AF into mutagenic intermediate(s) was enhanced after intragastric application . The mode of administration seems to be crucial in the induction of small intestinal enzymes required for metabolic and mutagenic activation of carcinogenic aromatic amines such as 2-AF.

Rev Infect Dis, 1986 Mar-Apr, 8(2), 189 - 207
Problems in salmonellosis: rationale for clinical trials with newer beta-lactam agents and quinolones; Bryan JP et al.; Disease syndromes caused by Salmonella species continue to be important, as evidenced by a major outbreak of infection due to multiresistant Salmonella typhimurium in 1985; this outbreak involved more than 12,000 people in five north-central states of the United States . Salmonella species have become progressively more resistant in recent years to the clinically useful antibiotics (trimethoprim-sulfamethoxazole, ampicillin, and chloramphenicol) . The clinical experience accumulated thus far indicates that two new classes of antimicrobial agents, the third-generation cephalosporins and the quinolones, offer significant potential for the treatment of specific problems in salmonellosis: bacteremia and enteric fever, meningitis, osteomyelitis, and the chronic carrier state.

Immunology, 1986 Mar, 57(3), 431 - 5
Cellular aspects of the longer-lasting immunity against mouse typhoid infection afforded by the live-cell and ribosomal vaccines; Kita E et al.; In order to compare the potential of salmonella vaccines prepared from Salmonella typhimurium to provide the longer-lasting protection from the aspects of cell-mediated immunity, groups of mice were immunized with optimal doses of the following preparations: live cells, ribosome-rich extract, acetone-killed cells, and heat-killed cells . At various intervals post-immunization, mouse peritoneal macrophages and splenic T cells were tested for biological activities . The capacity of each vaccine to confer mouse protection against a lethal challenge with S . typhimurium correlated with the degree of macrophage activation engendered by each of them in the early stage of immunization . In the late stage of immunization, the level of mouse protection conferred by each vaccine was found to be based on the capacity of T cells to respond to salmonella antigens, which correlated with the degree of adoptive immunity by T cells . The live-cell and ribosomal vaccines were superior to killed-cell vaccines in inducing the cell-mediated protection . Thus, the longer-lasting immunity provided by the live-cell and ribosomal vaccines can be accounted for by the fact that T cells of mice immunized with both vaccines have the persistent reactivity to salmonella antigens.

Mutat Res, 1986 Mar, 173(3), 169 - 76
Structure-activity relationships of nitro and methyl-nitro derivatives of indoline, indole, indazole and benzimidazole in Salmonella typhimurium; Vance WA et al.; The mutagenic activities of eleven nitro derivatives and eleven N-methyl-nitro derivatives of indoline, indole, indazole and benzimidazole were investigated in Salmonella TA98 and TA100 . The presence of a nitro group at C4 or C7 resulted in only weakly or nonmutagenic compounds, while a nitro group at C2, C5 or C6 usually resulted in measurable mutagenic activity in the non-N-methylated compounds . Methylation of a ring nitrogen usually reduced the mutagenic activity of these nitroheterocyclics except 2-nitro-benzimidazole, which resulted in a better than 300-fold increase in mutagenic activity . A proposed mechanism for the increased mutagenic activity obtained by methylation of imidazole nitrogens may provide insights into the reasons for the potent mutagenicities observed for several similarly methylated cooked-food mutagens.

Mutat Res, 1986 Mar, 169(3), 93 - 103
Characterization of bacterial mutagenicity mediated by 13-hydroxy-ent-kaurenoic acid (steviol) and several structurally-related derivatives and evaluation of potential to induce glutathione S-transferase in mice; Pezzuto JM et al.; Stevioside is a sweet-tasting diterpene glycoside that is derived from Stevia rebaudiana (Bertoni) Bertoni (Compositae) . It is used commercially in Japan and other parts of the world as a sucrose substitute . Whereas stevioside demonstrates no mutagenic activity in a variety of test systems, the aglycone, steviol (13-hydroxy-ent-kaurenoic acid), is mutagenic toward Salmonella typhimurium strain TM677 in the presence of a metabolic activating system derived from the liver of Aroclor 1254-pretreated rats . The required activating component is localized in the microsomal fraction of rat liver, suggestive of a cytochrome P-450-mediated reaction . Partially purified epoxide hydrolase does not inhibit steviol-induced mutagenicity, indicating that an active metabolite is not an epoxide that serves as a substrate for this enzyme preparation . The 13-hydroxy group of steviol is required for the expression of mutagenicity since ent-kaurenoic acid is nonmutagenic, and acetylation of steviol at this position negates mutagenicity . Similarly, diterpenes bearing a strong structural resemblance to steviol, cafestol and kahweol, were found to demonstrate no mutagenic activity toward Salmonella typhimurium TM677, as were their respective acetates and palmitic acid esters . Conversely, 19-O-beta-D-glucopyranosyl steviol, a potential hydrolysis product of stevioside, is mutagenic and bactericidal in the presence of a metabolic activating system . Additionally, in contrast to the nonmutagenic diterpenes cafestol and kahweol that are effective as inducers of glutathione S-transferase activity, evaluation by administration to mice proved steviol, isosteviol and various steviol glycosides to be inactive in this process . Thus, structural differences among these naturally occurring and semi-synthetic diterpenes appear to impart major differences in biological activity that may relate to human health upon dietary ingestion.

Mutat Res, 1986 Mar, 169(3), 71 - 9
Structure-mutagenicity relationships of chalcones and their oxides in the Salmonella assay; Rashid KA et al.; 31 p-monosubstituted chalcones (E-1, 3-diphenylpropene-1-one) and the corresponding oxides (E-1-benzoyl-2-phenyloxirane) were tested for mutagenic activity on two strains of Salmonella typhimurium (TA98 and TA100) with and without rat liver microsomal and cytosolic enzymes . Highest mutagenicity (3.0 revertants/nmole in either strain) was seen with the 4-nitrochalcone, especially after S9 activation . Epoxidation, in general, increased the mutagenic activity of the respective chalcone . Benzoyl (4') substituted chalcones and their oxides with an electron-withdrawing substituent (e.g., nitro, fluoro) usually had higher activity than their phenyl (4) substituted counterparts, whereas the converse was the case with electron-donating substituents (e.g., acetamido, methoxy) . Further multiple factorial analysis revealed that increasing hydrophilicity as indicated by the Hansch pi parameter, and resonance electronic contributions were more important than other factors including steric terms in explaining the mutagenicity of these compounds . Mutagenic effects of some chalcone oxides, particularly the 4-methoxy derivative, were markedly decreased by S9 treatment . The consequence of the weak-to-moderate mutagenicity of these compounds to dietary intake of hydroxylated and methoxylated chalcones is discussed.

J Med Microbiol, 1986 Mar, 21(2), 151 - 9
Electronmicroscopy studies on the bactericidal action of inflammatory leukocytes in murine salmonellosis; Guo YN et al.; Inbred female C3H mice were given 2 X 10(7) cfu virulent Salmonella typhimurium by intraperitoneal injection . Peritoneal washings were harvested between 3 h and 72 h after infection and examined by electronmicroscopy . There was evidence of intracellular killing by polymorphs and macrophages . The degeneration of intracellular salmonellae was seen initially as enlarging central electron-lucent areas in the cytoplasm and peripheral condensation of cytoplasmic granules, followed by disruption of the bacterial envelope and disintegration of cellular structure . Alternatively, the initial injury appeared as an irregular and discontinuous bacterial envelope with compression of the bacterium and diffuse condensation of cytoplasmic granules . It was also evident that virulent salmonellae multiplied extracellularly in the peritoneal cavity of the infected mice.

J Bacteriol, 1986 Mar, 165(3), 890 - 5
Acquisition of maltose chemotaxis in Salmonella typhimurium by the introduction of the Escherichia coli chemosensory transducer gene; Mizuno T et al.; Escherichia coli and Salmonella typhimurium are closely related species . However, E . coli cells show maltose chemotaxis but S . typhimurium cells do not . When an E . coli chemotransducer gene (tarE), the product of which is required for both aspartate and maltose chemotaxis, was introduced by using a plasmid vector into S . typhimurium cells with a defect in the corresponding gene (tarS), the transformant cells acquired the ability for both aspartate and maltose chemotaxis . In contrast, when the tars gene was introduced into tarE-deficient E . coli cells, the transformant cells acquired aspartate chemotaxis but not maltose chemotaxis . These results indicate that the absense of maltose chemotaxis in S . typhimurium is a consequence of the properties of the tars gene product.

J Bacteriol, 1986 Mar, 165(3), 780 - 6
Oxygen-regulated stimulons of Salmonella typhimurium identified by Mu d(Ap lac) operon fusions; Aliabadi Z et al.; Using the technique of Mu d1(Ap lac)-directed lacZ operon fusions, several oxygen-regulated genetic loci were identified in Salmonella typhimurium . Thirteen anaerobically inducible and six aerobically inducible operon fusions were identified . Based on control by the oxrA and oxrB regulatory loci, the anti-lacZ fusions were grouped into three classes: class I loci were regulated by both oxr loci, class II genes were regulated by oxrA only, and class III loci were not affected by either regulatory locus . Several of the anti-lacZ fusions required growth in complex medium before they exhibited the inducible phenotype . While the expression of some of these loci was repressed when organisms were grown in nitrate, others were stimulated by nitrate . Fusions into the hyd and phs loci were identified among the isolated anti-lacZ fusions . Six oxygen-inducible (oxi) operon fusions were also identified . Two of the oxi loci mapped near oxygen-regulatory loci: oxiC near oxrA and oxiE near oxyR . However, neither fusion appeared to occur within the regulatory locus . The data presented serve to further define the aerobic and anaerobic stimulons of S . typhimurium but indicate additional regulatory circuits above those already defined.

J Bacteriol, 1986 Mar, 165(3), 740 - 5
Autoregulation by tandem promoters of the Salmonella typhimurium LT2 metJ gene; Urbanowski ML et al.; Regulation of the Salmonella typhimurium metJ gene was examined by measuring beta-galactosidase activity in Escherichia coli strains lysogenic for a phage carrying a metJ-lacZ gene fusion . The results indicated that the metJ gene is regulated by its own gene product and by methionine supplementation to the growth medium . This autoregulatory mechanism involved two tandem promoters, pJ1 and pJ2, separated by approximately 65 base pairs . Deletion analysis permitted the assessment of the activity of promoters pJ1 and pJ2 individually . Promoter Pj1 was negatively regulated by the metJ gene product and by methionine . Although Pj2 regulation remained unclear, evidence is presented which suggests that it is not negatively regulated like pJ1.

Infect Immun, 1986 Mar, 51(3), 872 - 8
Salmonella typhimurium virulence genes necessary to exploit the Itys/s genotype of the mouse; Benjamin WH Jr et al.; The studies described in this paper provide evidence that the pathogenesis of Salmonella typhimurium in mice is dependent on interactions between particular genotypes of the infected mice and the infecting Salmonella strain . This conclusion was based on data obtained by infecting a panel of BXD recombinant inbred mice with each of three S . typhimurium strains . One of the S . typhimurium strains was a transconjugant (WB500) produced in an interrupted mating between the two other strains, one (SR-11) of high and the other (LT2-Z) of low virulence for BALB/c mice . We found that strain WB500 appeared to have inherited from SR-11 a gene (or genes) which was required to exploit the Itys/s genotype in mice . However, WB500 apparently lacked other SR-11 virulence gene(s), whose effect on the in vivo growth of SR-11 was independent of the Ity genotype of the mouse.

Carcinogenesis, 1986 Mar, 7(3), 431 - 4
Mutagenicity of the mercapturic acid and other S-containing derivatives of hexachloro-1,3-butadiene; Wild D et al.; The main metabolic pathway of the genotoxic environmental contaminant hexachloro-1,3-butadiene (HCBD) is the direct conjugation reaction with glutathione . To establish structure-effect relationships we studied the mutagenic activity of four S-containing HCBD conjugates with and without metabolic activating enzymes (S9 mix) in Salmonella typhimurium . The N-acetyl-S-pentachlorobutadienyl-L-cysteine (mercapturic acid) was clearly mutagenic after metabolic activation; its mutagenic activity was 48.6 revertants/micrograms or 18.7 revertants/nmol, which is, on a molar basis, a mutagenic response 80 times greater than that of the parent compound HCBD . The mutagenic effect of the mercapturic acid rather decreased by addition to the pre-incubation system of pyridoxal 5'-phosphate, a co-factor of the enzyme beta-lyase . Methyl-N-acetyl-S-pentachlorobutadienyl-D,L-homocysteinate, structurally closely related to mercapturic acid, exerted a weak mutagenic effect comparable to that of HCBD . The two S-containing HCBD metabolites (S-pentachlorobutadienyl-mercaptoacetic acid and pentachlorobutadienyl-methylthioether) did not reveal significant mutagenic effects . The results indicate the involvement of the enzyme N-deacetylase which catalyzes the conversion of mercapturic acid to the HCBD-cysteine conjugate . In addition a high substrate specificity of the C-S bond-cleaving enzyme beta-lyase was observed.

Cell Immunol, 1986 Mar, 98(1), 78 - 92
Stimulation of mouse B cells by a factor that coisolates with T-cell proteoglycan; Levitt D et al.; We have isolated a factor that copurifies with chondroitin sulfate proteoglycan secreted by mouse splenocytes and some murine T-cell hybridomas . This factor will stimulate proliferation and plaque-forming cell differentiation of B lymphocytes from mouse spleens, even after T cells have been depleted (less than 2% Thy 1.2-bearing cells) . Adherent macrophages enhance the activity of this factor, but their function can be replaced in macrophage- and T-cell-depleted populations by small concentrations of a protein mitogen from Salmonella typhimurium . The stimulatory fraction contains chondroitin sulfate, a major protein which has a molecular weight of 74,000 and a minor moiety at 50,000 . Stimulatory activity of this material is destroyed by (i) boiling, (ii) mild alkali treatment, and (iii) protease digestion . It is unaffected by RNase and chondroitinase treatments, suggesting that the factor is a protein . Our data define a new B-cell stimulatory substance(s) and suggest that it may be associated with chondroitin sulfate proteoglycan secreted by immune cells.

Carcinogenesis, 1986 Mar, 7(3), 371 - 4
The blocking effect of disodium cromoglycate on carcinogenesis induced by benzo{a}pyrene; Vlckova A et al.; Subcutaneous injection of 3 mg benzo{a}pyrene into the right hind leg of experimental rats resulted in local tumors in the area of application in all the animals . The same dose of disodium cromoglycate applied prior to benzo{a}pyrene prevented tumor formation or provoked a significant inhibition of the carcinogenic process, e.g . delay of tumor formation and of a reduced size, a number of mitoses and cytological abnormalities and a prolongation of the animal's life . In the in vitro Salmonella typhimurium mutation assay of Ames, disodium cromoglycate eliminated toxicity and mutagenicity of 5-nitro-2-furylacrylic acid . The results would suggest that the initial response of the cell to benzo{a}pyrene had been conducted through the calcium-dependent exocytic pathway, which can be efficiently blocked by disodium cromoglycate, probably by preventing the signals increase in free intracellular calcium concentration . The preserved calcium balance as a consequence of the effect of disodium cromoglycate on benzo{a}pyrene-induced cell response might be a factor responsible for the carcinogenesis inhibition phenomena . The results of the in vitro study in correlation with those obtained in vivo support the suggestion that disodium cromoglycate may influence parallel structures in various cell types.

Genetics, 1986 Mar, 112(3), 429 - 39
Activity of Chi recombinational hotspots in Salmonella typhimurium; Smith GR et al.; Chi sites have previously been shown to stimulate homologous recombination by the Escherichia coli RecBC pathway . To test the activity of Chi in another organism, bacteriophage lambda crosses were carried out in Salmonella typhimurium strains bearing the E . coli lambda receptor protein . Chi is active in these crosses in S . typhimurium, but is less active than in the same crosses carried out in E . coli . The lower Chi activity in S . typhimurium appears to be intrinsic to the S . typhimurium RecBC enzyme, since the Chi activity in E . coli-S . typhimurium hybrids depends on the species of origin of their RecBC enzyme . For these studies we constructed and F' factor and a pBR322-derived plasmid carrying the thyA+ recC+ recB+ argA+ region of the S . typhimurium chromosome.

Mutagenesis, 1986 Mar, 1(2), 125 - 30
Bacterial genotoxicity of nitrosated famotidine; De Flora S et al.; Famotidine, a histamine H2-receptor antagonist, was devoid of mutagenic activity in seven his- Salmonella typhimurium strains (TA1535, TA1537, TA1538, TA97, TA98, TA100 and TA102) and was equitoxic in repair-proficient (WP2) and repair-deficient (WP2uvrA, WP67, CM561, CM571, WP100 and CM871) Escherichia coli strains, both in the presence and in the absence of S9 mix containing liver S9 fractions from Aroclor-treated rats . However, after a short pre-incubation step with nitrite in an acidic environment, the drug increased, by a direct mechanism, the number of his+ revertants in Salmonella strains TA100, TA102 and TA97 (a decrease of mutagenicity being conversely observed in TA1535) and of trp+ revertants in E . coli strains WP2uvrA and WP67 . Moreover, it enhanced the induction of non-reparable DNA damage in E . coli strains simultaneously lacking the uvrA-dependent excision repair and the lexA post-replication repair pathways . The mutagenicity of acidified nitrite-famotidine mixtures was related to doses of both precursors, with a maximum production of mutagenic derivatives in a slight molar excess of nitrite . The optimal pH of the nitrosation reaction (2.0) was intermediate between the one required for cimetidine (1.5) and ranitidine (2.5) . Potency of famotidine as a precursor of mutagenic derivatives was considerably lower than the one of the other two H2 blockers . The nitrosation products of all three drugs mainly induced base-pair substitutions in Salmonella DNA, to a greater extent at sites containing G.C base pairs (strain TA100) in the case of famotidine and cimetidine, and at sites containing A.T base pairs (TA102) in the case of ranitidine.(ABSTRACT TRUNCATED AT 250 WORDS)

J Biol Chem, 1986 Feb 15, 261(5), 2441 - 50
Nucleotide sequence and in vivo expression of the ilvY and ilvC genes in Escherichia coli K12 . Transcription from divergent overlapping promoters; Wek RC et al.; The ilvC gene of Escherichia coli K12 encodes acetohydroxy acid isomeroreductase, the second enzyme in the parallel isoleucine-valine biosynthetic pathway . Previous data have shown that transcription of the ilvC gene is induced by the acetohydroxy acid isomeroreductase substrates, acetohydroxybutyrate or acetolactate, and that this substrate induction of ilvC expression is mediated by a positive activator encoded by the ilvY gene . We report here the isolation and complete nucleotide sequence of the ilvY and ilvC genes . The ilvY and ilvC genes encode polypeptides of Mr 33,200 and 54,000, respectively . In vitro transcription-translation of these gene templates results in the synthesis of gene products of these identical molecular weights . The ilvC gene is transcribed in the same direction as the genes of the adjacent ilvGMEDA operon . The ilvY gene is transcribed in a direction opposite to the ilvC and ilvGMEDA genes . The in vivo transcriptional initiation sites of the ilvY and ilvC genes have been determined by S1 nuclease protection experiments . These transcriptional initiation sites are 45 nucleotides apart, and transcription of the ilvY and ilvC genes is initiated via divergent overlapping promoters . The nucleotide sequence of the ilvY and ilvC promoters and 5'-coding regions of Salmonella typhimurium LT2 have been determined . A comparison of these sequences with E . coli K12 suggests regions important in the promotion, regulation, and translation of the ilvY and ilvC genes . A model is presented in which the ilvY-encoded activator binds to an operator site in the overlapping promoter region and reciprocally regulates the transcription of the ilvY and ilvC genes . The carboxyl-terminal amino acid sequence of threonine deaminase encoded by the ilvA gene of the ilv-GMEDA operon of E . coli K12 has been identified by homology with the previously deduced threonine deaminase amino acid sequence encoded by the ilv1 gene of Saccharomyces cerevisiae . Based on the deduced amino acid sequences of the ilvA and ilvY genes, the translational termination codons for both genes are shown to be separated by 52 nucleotides . The proximity of the ilvA and ilvY genes suggests that the 3'-ends of these transcripts overlap.

Biochem Biophys Res Commun, 1986 Feb 13, 134(3), 1136 - 41
Biosynthesis of thiamine: origin of the methyl carbon atom of the pyrimidine moiety in Salmonella typhimurium; Estramareix B et al.; Two biosynthetic, unevenly labeled samples of 5-aminoimidazole riboside were prepared . The incorporation of radioactivity from these labeled samples was studied in a Salmonella typhimurium strain able to use this riboside as precursor of the pyrimidine moiety of thiamine . In one sample, the ribose part was labeled almost equally at C-1' and C-2' and threefold more at C-3' but unlabeled at C-4' and C-5' . The pyrimidine moiety of thiamine derived from it was found almost inactive at C-5, C-7; the specific activity of the methyl carbon atom was found close to that of C-1' or C-2' of ribose in the precursor . On the other hand, only a poor incorporation of radioactivity occurred from a sample in which the ribose part was labeled mainly at C-1' . We conclude that C-5, C-7 of the pyrimidine moiety of thiamine derive from C-4', C-5' and the methyl carbon atom of the pyrimidine derives from C-2' of the ribose part of 5-aminoimidazole ribotide.

Eur J Biochem, 1986 Feb 3, 154(3), 673 - 6
Chain length heterogeneity of lipopolysaccharide released from Salmonella typhimurium by ethylenediaminetetraacetic acid or polycations; Hukari R et al.; Cells of two smooth Salmonella typhimurium strains (SL696 and SH4247) were treated with ethylenediaminetetraacetic acid (EDTA) and the polycations poly(L-lysine) and protamine to monitor both quantitatively and qualitatively the release of {14C} galactose-labelled lipopolysaccharide into the medium to find out whether these effector substances caused selective release of certain fractions from the initially heterogenous lipopolysaccharide population . Each one of the substances released considerable amounts of lipopolysaccharide into the medium . Analysis by sodium dodecyl sulphate/polyacrylamide gel electrophoresis followed by autoradiography showed that the total lipopolysaccharide (from isolated membranes) and the released materials produced coincident banding patterns, each with a high degree of O side-chain length heterogeneity . Densitometric scans of the autoradiograms were analyzed for possible differences in the distribution and relative abundance of lipopolysaccharide molecules with different O chain lengths . It was found that in SL696 the released materials were identical to the total lipopolysaccharide; in SH4247 subtle deviations from the total lipopolysaccharide were seen . We conclude from these results that lipopolysaccharide molecules with short and long O side chains are linked to and stabilized in the outer membrane by similar mechanisms equally susceptible to the effects of EDTA and polycations.

Am J Vet Res, 1986 Feb, 47(2), 232 - 5
Characteristics of Salmonella isolated from animals at a veterinary medical teaching hospital; Ikeda JS et al.; Salmonella belonging to 47 serotypes was isolated from animals at the University of California Veterinary Medical Teaching Hospital during the years 1974 to 1983 . Salmonella belonging to 12 serotypes accounted for 89% of the 725 isolates . Salmonella typhimurium (including var copenhagen) was the most commonly isolated serotype, but during 1981 to 1983, S krefeld and S saint-paul were predominant . Certain serotypes seemed to be isolated more frequently from extraintestinal sources (S typhi-suis, S dublin) . Although resistance to ampicillin, kanamycin, neomycin, streptomycin, and sulfonamides was common (greater than 60% of the isolates were resistant), resistance to chloramphenicol, gentamicin, and trimethoprim-sulfonamides was infrequent, except for isolates of S krefeld and S saint-paul.

Carcinogenesis, 1986 Feb, 7(2), 207 - 14
A 7-hydroxymethyl sulphate ester as an active metabolite of the carcinogen, 7-hydroxymethylbenz{a}anthracene; Watabe T et al.; 7-Hydroxymethylbenz{a}anthracene (7-HBA) showed potent mutagenicity towards Salmonella typhimurium TA 98 in the presence of untreated rat liver cytosol fortified with the PAPS-generating system, sodium sulphate and ATP . No mutagenic activity was observed either when the cytosol was boiled or when sodium sulphate or ATP was omitted from the assay medium . A highly reactive sulphate ester of 7-HBA was isolated and identified from the medium . It had a half-life of 3.5 min at 37 degrees C and pH 7.4 in water and showed potent, intrinsic mutagenicity towards TA 98 . The mutagenicity of 7-HBA sulphate was almost completely retarded in the presence of the cytosol and glutathione . From the biological systems containing glutathione a non-mutagenic and stable glutathione conjugate was isolated that was assigned as S-(benz{a}anthracen-7-yl)methylglutathione . 7-HBA sulphate covalently bound to calf thymus DNA and cytosolic proteins . A fluorospectroscopic study indicated that the carcinogen bound to the biomacromolecules through its 7-methylene group with loss of a sulphate anion as a leaving group.

Br J Rheumatol, 1986 Feb, 25(1), 13 - 9
Salmonella reactive arthritis: serum and secretory antibodies in eight patients identified after a large outbreak; Trull AK et al.; Serial measurements of serum and secretory antibodies to Salmonella typhimurium were made by ELISA in eight patients with suspected reactive arthritis identified after a large outbreak of Salmonella gastroenteritis . All three patients from whom Salmonella had been isolated developed significant serum IgG, IgA and IgM antibody responses . Only one of the three possessed HLA-B27 . A further three patients, two with HLA-B27, had raised antibodies, although none had experienced gastroenteritis . Salmonella infection was not confirmed in the remaining two patients . The three B27-negative patients with confirmed reactive arthritis had HLA-B locus antigens which serologically cross-react with B27 . One of six patients with confirmed reactive arthritis was under the age of 25 years whereas 256 of 418 (61%) patients with uncomplicated enteritis were under this age . The development of reactive arthritis may follow subclinical Salmonella infection and is influenced by genetic and age-related factors.

Antimicrob Agents Chemother, 1986 Feb, 29(2), 239 - 43
Emergence of aminoglycoside 3-N-acetyltransferase IV in Escherichia coli and Salmonella typhimurium isolated from animals in France; Chaslus-Dancla E et al.; We studied two outbreaks of calf salmonellosis caused by apramycin and gentamicin-resistant Salmonella typhimurium strains . In both cases, the responsible strains were resistant to ampicillin, chloramphenicol, kanamycin, streptomycin, tetracycline, and trimethoprim; one strain was also resistant to nalidixic acid in one outbreak . A systematic survey of the intestinal Escherichia coli strains of calves from the two affected flocks showed that 11 of 24 animals sampled were also colonized by apramycin- and gentamicin-resistant E . coli strains . These isolates belonged to four biotypes and were resistant to ampicillin, chloramphenicol, kanamycin, streptomycin, tetracycline, trimethoprim, and nalidixic acid . All of the strains were resistant to high levels of apramycin (MICs, 512 to 1,024 micrograms/ml) and to gentamicin (MICs, 8 to 32 micrograms/ml), and these resistances were always transferred en bloc . In S . typhimurium, this coresistance was borne by plasmids that were approximately 39 kilobases long (outbreak 1) or 90 kilobases long (outbreak 2), whereas in E . coli, the coresistance was due to plasmids that were approximately 110 kilobases long in both outbreaks . The two plasmids of Salmonella and four plasmids of E . coli encoded type IV aminoglycoside 3-N-acetyltransferases . The intensive use of curative and preventive treatments in calf production could be responsible for the emergence of enzymic resistance to apramycin and gentamicin.

J Gen Microbiol, 1986 Feb, 132 ( Pt 2), 231 - 5
Stabilization of glucose-starved Escherichia coli K12 and Salmonella typhimurium LT2 by peptidase-deficient mutants; Bockman AT et al.; Escherichia coli K12 and Salmonella typhimurium LT2 cells were stabilized during carbon starvation in the presence of peptidase-deficient mutant strains . The rate of loss of viability of the wild-type S . typhimurium strain was decreased an average of 2-fold, and the rate for the wild-type E . coli strain was decreased about 2.3-fold, when either was starved in the presence of the multiply peptidase-deficient S . typhimurium strain TN852; other peptidase-deficient strains exhibited similar stabilizing effects . Starving wild-type S . typhimurium LT2 cells utilized peptides excreted by the starving peptidase-deficient cells for protein synthesis, and, to a lesser extent, as respiratory substrates . Provision of free amino acids in steady-state levels to starving E . coli K12 cells in a cell recycle apparatus had a stabilizing effect similar to that of mixing with peptidase-deficient cells.

J Clin Microbiol, 1986 Feb, 23(2), 360 - 5
Plasmid profile analysis in epidemiological studies of animal Salmonella typhimurium infection in Japan; Nakamura M et al.; Plasmid profiles were investigated in 65 isolates of Salmonella typhimurium derived from animal outbreaks during the period of 1978 through 1983 in Japan . Incidence of plasmids, drug-resistance, and conjugative R plasmids were extraordinarily high in these isolates . This high incidence reflects the prophylactic and therapeutic use of antibiotics . Most isolates from diseased animals, cohabiting animals, and each farm showed the same or similar plasmid patterns . However, there was a difference in plasmid patterns within strains isolated from each of several animals . It may be that one or two plasmids were introduced or deleted in these strains, leading to the difference discerned in strains isolated from the same animal . It was also shown that during one epidemic, two strains of S . typhimurium were involved that could be distinguished by plasmid profile analysis . Our conclusion is that when S . typhimurium strains isolated from animals reared in limited areas exhibit identical or similar plasmid patterns, they are derived from the same source and that when strains isolated in a limited area exhibit quite a different plasmid pattern, these strains are derived from independent sources.

J Appl Bacteriol, 1986 Feb, 60(2), 93 - 6
A note on survival of salmonellas during anaerobic digestion of cattle dung; Gadre RV et al.; Anaerobic digestion of night soil with cattle dung slurry in biogas plants is advocated in Indian villages as a means of disposal of human excreta in the absence of conventional sanitary systems . Although intestinal pathogens are likely to be eliminated during anaerobic digestion, there is no conclusive evidence that this is so . Large numbers of saprophytic organisms in the fermenting mass make it impossible to detect the residual pathogens . Use of an antibiotic-resistant strain of Salmonella typhimurium as a test organism to study its survival during anaerobic digestion showed that the organism is totally eliminated in nine days.

Biochem Int, 1986 Feb, 12(2), 267 - 77
Purification and characterization of bacteriophage 9NA lysozyme; Verma M et al.; Bacteriophage 9NA is a virulent phage of Salmonella typhimurium which induces a lysozyme in host cells toward the later stages of its multiplication . 9NA lysozyme has been purified about 1000 fold starting from the lysate of 9NA infected cells . The enzyme has an optimum pH between 7 and 8 and its activity is dependent on the ionic strength of the assay medium . Salts like NaCl and KCl are inhibitory to the lysozyme . Gram-negative cells act as better substrate for the lysozyme than do Gram-positive cells . The enzyme has a molecular weight of about 2.1 X 10(4) and rapidly loses its activity at temperatures higher than 45 degrees C . The properties of 9NA lysozyme have been compared with those of T4, lambda and P22 lysozymes.

Zh Mikrobiol Epidemiol Immunobiol, 1986 Feb, (2), 24 - 7
{Effect of interferon type I on the in vivo persistence of Salmonella typhimurium}; Fil'chakov IV et al.; The influence of type I interferon on the persistence of S . typhimurium in the body of mice has been studied . The injection of the preparation of interferon has been shown to be conductive to the survival of the animals and to reduce the time of Salmonella persistence in the body . The injection of interferon enhances the phagocytic activity of macrophages in the peritoneal exudate of mice.

Mutat Res, 1986 Feb, 164(1), 41 - 51
Activation of mutagens by hepatocytes and liver 9000 X g supernatant from human origin in the Salmonella typhimurium mutagenicity assay . Comparison with rat liver preparations; Neis JM et al.; The mutagenicity of 10 known genotoxic compounds, of several chemical classes, was measured in Salmonella typhimurium mutagenicity assays comprising isolated human hepatocytes or human liver 9000 X g supernatant (S9) from 4 different individuals, as activating system . The mutagenic activity of several compounds as determined with the Salmonella/hepatocyte suspension assay showed obvious differences when compared with the values obtained in the Salmonella/S9 plate assay . For instance, the mutagenic activity of BZ, DMN and DEN appeared to be much higher in the hepatocyte assay than in the S9 assay . However, 2-AF and 2-AAF were activated more effectively into mutagens in the S9 assay than in the hepatocyte assay . 2-AF was slightly more mutagenic than 2-AAF in the hepatocyte assay, whereas it was far more mutagenic than 2-AAF in the S9 assay . DMN was found more mutagenic than DEN in the hepatocyte assay, whereas in the S9 assay DEN appeared to be slightly more mutagenic . Furthermore, great interindividual differences in the metabolic activation of certain compounds, e.g . BZ and DMN, were observed in the hepatocyte suspension assay, whereas these variations were less evident in the S9 plate assay . Comparison of the mutagenicity data obtained with the human liver preparations, with those obtained with rat liver preparations, showed great interspecies differences in the capacity to activate certain chemicals into mutagens . The use of human liver preparations, in particular isolated human hepatocytes, may be of great value in studies on inter- and intraspecies variations in metabolic activation of genotoxic agents.

J Med Microbiol, 1986 Feb, 21(1), 19 - 23
Enterotoxin production by Salmonella typhimurium strains of different virulence; Wallis TS et al.; Six strains of Salmonella typhimurium (TML, W118, LT7, SL1027, M206 and Thax-1) of known virulence and ability to induce fluid secretion when inoculated into the rabbit ileum were examined for enterotoxin production . Enterotoxic activity, assayed in the rabbit ileal-loop test, was detected in polymyxin-B extracts from all strains (with the possible exception of Thax-1) cultured for 6 h in casamino acid-yeast extract medium . The extracts were inactive in tissue-culture assays with CHO, Y-1 adrenal and Vero cells, and in the infant mouse assay for enterotoxin . There was no correlation between enterotoxigenicity in vitro and the ability of whole organisms to induce fluid secretion in vivo . The significance of these results in relation to salmonellosis is discussed.

Am J Pathol, 1986 Feb, 122(2), 323 - 34
Comparison of inflammatory reactions induced by intraarticular injection of bacterial cell wall polymers; Esser RE et al.; Cell wall polymers isolated from group A streptococci, as well as lipopolysaccharide from Salmonella typhimurium and synthetic muramyl dipeptide, were injected into the ankle joints of rats . The inflammatory responses were assessed by gross and histologic examination, and edema was measured by accumulation of radiolabeled albumin in the limbs . The isolated group-specific polysaccharide induced extensive edema of the articular and periarticular tissue immediately after injection, and this resolved in 24 hours . The peptidoglycan moiety did not produce early edema, but induced an acute exudative reaction followed by a proliferative synovitis which resolved after 5 days . Reactions induced by covalently bound complexes of peptidoglycan and the group-specific polysaccharide (PG-APS) varied, depending on the size of the complex . Small fragments, derived from mutanolysin digestion, caused both an acute edematous reaction and transient arthritis . Larger fragments did not cause the immediate edematous reaction, but induced an acute arthritis that appeared within 24 hours and evolved into a chronic process . Episodes of recurrent inflammation, a distinctive feature of joint inflammation induced by systemic injection of PG-APS polymers, were not observed following intraarticular injection of any of the cell wall polymers . The relative susceptibility of different rat strains to arthritis induced by intraarticular injection paralleled the responses to systemic injection of PG-APS . These results demonstrate that variations in arthropathogenicity are due, in part, to inherent differences in the phlogistic activities of different cell wall polymers, and that the genetic control of susceptibility involves regulation of the inflammatory responses rather than the quantity of cell wall distributed to the joint.

Mutat Res, 1986 Feb, 173(2), 111 - 5
Chlorophyllin: a potent antimutagen against environmental and dietary complex mixtures; Ong TM et al.; Chlorophyllin, the sodium and copper salt of chlorophyll, was tested for its ability to inhibit the mutagenic activity of a variety of complex mixtures--extracts of fried beef, fried shredded pork, red grape juice, red wine, cigarette smoke, tobacco snuff, chewing tobacco, airborne particles, coal dust and diesel emission particles--in strain TA98 of Salmonella typhimurium . Chlorophyllin was highly effective against the mutagenicity (90-100% inhibition) of 8 of these 10 mixtures . The mutagenicity of the other 2 mixtures was inhibited 75-80% at the highest concentration of chlorophyllin studied . Control and reconstruction experiments showed that chlorophyllin was not toxic to Salmonella at the concentrations used . The antimutagenic activity of chlorophyllin was heat-stable . The mechanism of the antimutagenicity of chlorophyllin in these experiments is not known; however, chlorophyllin is an antioxidant . Scavenging of radicals and/or interaction with the active group of mutagenic compounds may be responsible for its antimutagenic activity . The data reported here indicate that chlorophyllin is potentially useful as an antimutagenic agent.

Cancer Res, 1986 Feb, 46(2), 524 - 31
Monoclonal antibody-directed analysis of cytochrome P-450-dependent monooxygenases and mutagen activation in the livers of DBA/2 and C57BL/6 mice; Hietanen E et al.; Monoclonal antibodies (MAb 1-7-1 and Mab 2-66-3) specific for cytochrome P-450 (cyt . P-450) isozymes inhibited the metabolism of carcinogens, other xenobiotics, and endogenous compounds in two strains of mice . Postmitochondrial liver supernatant (S9) was prepared from untreated, 3-methylcholanthrene-treated, phenobarbital-treated, and pregnenolone 16 alpha-carbonitrile-treated C57BL/6 (B6) and DBA/2 (D2) mice . The modifying effect of two types of MAb to a 3-methylcholanthrene-induced cyt . P-450 and a phenobarbital-induced cyt . P-450 was investigated for: (a) S9-mediated mutagenicity of aflatoxin B1, benzo(a)pyrene 7,8-dihydrodiol, 2-acetylaminofluorene, and N-nitrosomorpholine in Salmonella typhimurium strains; and (b) the activity of aryl hydrocarbon hydroxylase, ethoxycoumarin O-deethylase, ethoxyresorufin O-deethylase, aminopyrine N-demethylase, and testosterone 6 beta-, 7 alpha-, and 16 beta-hydroxylases . With certain S9s, MAb-1-7-1 inhibited only those cytochrome P-450 isozymes involved predominantly in activity of aryl hydrocarbon hydroxylase, ethoxyresorufin O-deethylase, and ethoxycoumarin O-deethylase and mutagenicity of 2-acetylaminofluorene and benzo(a)pyrene 7,8-dihydrodiol; MAb 2-66-3 inhibited only those involved in aminopyrine N-demethylase and testosterone 6 beta-, 7 alpha, and 16 beta-hydroxylase activity and aflatoxin B1 mutagenicity . Both Mab 1-7-1 and MAb 2-66-3 inhibited cytochrome P-450 isozyme(s) implicated predominantly in testosterone 7 alpha-hydroxylation in S9 from pregnenolone 16 alpha-carbonitrile-treated B6 mice . MAb 1-7-1 did not inhibit N-nitrosomorpholine mutagenicity and MAb 2-66-3 increased it by 2- to 6-fold depending on the source of S9 . Using these MAbs, it is thus possible to identify the contribution of the epitope-defined single or class of cyt . P-450 to specific metabolic reactions in S9 from untreated and inducer-treated mice.

J Bacteriol, 1986 Feb, 165(2), 434 - 42
opp-lac Operon fusions and transcriptional regulation of the Escherichia coli trp-linked oligopeptide permease; Andrews JC et al.; The transcriptional regulation of the Escherichia coli trp-linked opp operon that encodes the oligopeptide permease was investigated by using lambda plac Mu51-generated lac operon fusions . Synthesis of beta-galactosidase by strains harboring oppA-lac, oppB-lac, and oppD-lac fusions occurred at a basal level when the fusion-containing strains were grown in minimal medium . The addition of L-leucine or L-alanine to exponentially growing, aerobic cultures or shifting the aerobic fusion-containing strains to anaerobic growth medium increased the synthesis of beta-galactosidase from all opp-lac fusions . When transcription of the opp operon was induced by L-leucine, the differential rate of beta-galactosidase synthesis from each opp-lac fusion increased 8- to 10-fold; this increased rate of lacZ expression from the opp-lac fusions resulted in a 5- to 6-fold increase in total beta-galactosidase activity after maximum expression was achieved . Importantly, when F'123 derivatives harboring independently isolated E . coli opp-lac operon fusions were introduced into E . coli and Salmonella typhimurium, the data clearly demonstrated that the E . coli opp operon was expressed identically and responded to the same transcriptional regulatory signals in both E . coli and S . typhimurium . A comparison of beta-galactosidase synthesis by E . coli strains harboring an opp-lac operon fusion and either an oppE+ locus or an oppE mutation demonstrated that the reduction in peptide transport produced by the oppE mutation does not result from a decrease in the level of opp operon transcription.

J Immunol, 1986 Feb 1, 136(3), 1074 - 80
Differences in initial rate of intracellular killing of Salmonella typhimurium by granulocytes of Salmonella-susceptible C57BL/10 mice and Salmonella-resistant CBA mice; van Dissel JT et al.; The contribution of granulocytes to differences in the innate susceptibility of mouse strains to infection by Salmonella typhimurium was assessed on the basis of the size and composition of the inflammatory exudate after i.p . injection of bacteria and the intracellular killing of the bacteria by exudate peritoneal cells and blood granulocytes of resistant CBA and susceptible C57BL/10 mice . The increase in the numbers of both peritoneal granulocytes and macrophages 24 hr after i.p . injection of various numbers of live S . typhimurium was two to four times higher in C57BL/10 mice (p less than 0.05) than in CBA mice . However, despite the larger number of phagocytes in the inflammatory exudate, the numbers of viable S . typhimurium in the peritoneal cavity 24 hr after injection was higher (p less than 0.01) in C57BL/10 mice than in CBA mice . Because the proportion of noningested bacteria was similar in the two mouse strains (less than 30%), these findings indicate a difference in the rate of intracellular killing of the bacteria by exudate peritoneal cells (greater than 75% granulocytes) of the two mouse strains . Subsequent determination of the initial rate of intracellular killing (Kk) of S . typhimurium revealed that after phagocytosis of the bacteria in vivo, exudate peritoneal granulocytes (harvested 24 hr after i.p . injection of 10(3) live S . typhimurium) of CBA mice killed S . typhimurium twice as efficiently (Kk = 0.014 min-1; p less than 0.01) as exudate granulocytes of C57BL/10 mice (Kk = 0.008 min-1) did . Similarly, the initial rate of intracellular killing of the ingested S . typhimurium by blood granulocytes of CBA mice (Kk = 0.017 min-1) was two times higher (p less than 0.01) than that of C57BL/10 mice (Kk = 0.007 min-1) . These findings may be specific for S . typhimurium, because L . monocytogenes were killed with equal efficiency by exudate granulocytes and blood granulocytes of these mouse strains (p greater than 0.20) . The results of the present study are relevant with respect to the innate resistance of mice to S . typhimurium, particularly during the initial phase of infection when the inflammatory exudate contains predominantly granulocytes.

Cancer Res, 1986 Feb, 46(2), 558 - 66
Inhibitory effect of 3-hydroxybenzo(a)pyrene on the mutagenicity and tumorigenicity of (+/-)-7 beta, 8 alpha-dihydroxy-9 alpha, 10 alpha-epoxy-7,8,9,10-tetrahydrobenzo(a)pyrene; Huang MT et al.; The 12 isomeric phenols of benzo(a)pyrene were tested for their ability to inhibit the mutagenic activity of (+/-)-7 beta, 8 alpha-dihydroxy-9 alpha, 10 alpha-epoxy-7,8,9,10-tetrahydrobenzo(a)pyrene {B(a)P 7,8-diol-9,10-epoxide-2}, an ultimate mutagenic and carcinogenic metabolite of benzo(a)pyrene . 3-Hydroxybenzo(a)pyrene {3-HO-B(a)P}, a major metabolite of benzo(a)pyrene, was the most potent antagonist tested . Approximately 3 nmol of 3-HO-B(a)P, 14 nmol of 10-HO-B(a)P, and 5-8 nmol of 1-, 2-, 4-, 5-, 6-, 7-, 8-, 9-, 11-, and 12-HO-B(a)P inhibited the mutagenic activity of 0.05 nmol of B(a)P 7,8-diol-9,10-epoxide-2 by 50% in Salmonella typhimurium strain TA 100 . The importance of the phenolic group for antimutagenic activity was indicated by the lack of antimutagenic activity of benzo(a)pyrene itself . 3-HO-B(a)P also inhibited the mutagenic activity resulting from the metabolic activation of benzo(a)pyrene and (+/-)-trans-7,8-dihydroxy-7,8-dihydrobenzo(a)pyrene by rat liver microsomes . This inhibition may have resulted from an effect of 3-HO-B(a)P on the metabolic activation of these carcinogens and/or from a direct effect on the action of B(a)P 7,8-diol-9,10-epoxide-2 . In a mammalian cell culture system utilizing Chinese hamster V79 cells, 3-HO-B(a)P (8 microM) inhibited the mutagenicity of B(a)P 7,8-diol-9,10-epoxide-2 (0.2 microM) by 50% . Although 3-HO-B(a)P was a potent inhibitor of the mutagenic activity of bay-region diol epoxides of benzo(a)pyrene, dibenzo(a,h)pyrene, and dibenzo(a,i)pyrene in S . typhimurium strain TA 100, higher concentrations of 3-HO-B(a)P were needed to inhibit the mutagenicity of the chemically less reactive benzo(a)pyrene 4,5-oxide and the bay-region diol epoxides of benz(a)anthracene, chrysene, and benzo(c)phenanthrene . Both 3-HO-B(a)P and 10-HO-B(a)P accelerated the disappearance of B(a)P 7,8-diol-9,10-epoxide-2 from 1:9 dioxane-water solutions at pH 7 and 25 degrees C . 3-HO-B(a)P, the most effective antimutagen of the B(a)P phenols tested, was much more reactive with the diol epoxide than 10-HO-B(a)P, the least effective antimutagen . The rate constant for the reaction of 3-HO-B(a)P with the diol epoxide exhibited a nonlinear (greater than first-order) dependence on the concentration of the phenol . Evidence was obtained for covalent adduct formation between the diol epoxide and each of the two phenols.(ABSTRACT TRUNCATED AT 400 WORDS)

Mol Gen Genet, 1986 Feb, 202(2), 327 - 30
Reversion and immobilization of phage Mud1 cts (Apr lac) insertion mutations in Salmonella typhimurium; Blum P et al.; Phage Mud1 cts (Apr lac), or Mud1, insertion mutations may be accompanied by adjacent deletion formation which can complicate use of lac fusions generated with this phage for gene regulatory studies . As for phage Mu insertion mutations, phage Mud1 insertions fail to revert at significant frequency (whether or not accompanied by an adjacent deletion) . We describe isolation of revertible (X mutant) derivatives of phage Mud1 in Salmonella typhimurium . The X mutant derivatives allow use of reversion as a simple test to determine whether a Mud1 insertion has occurred precisely without an adjacent deletion that may have fused the lac genes to a promoter outside of the gene of interest . In addition, a simple method for stabilizing Mud1 generated lac fusions against subsequent transposition is described.

J Bacteriol, 1986 Feb, 165(2), 386 - 92
Sensitivity of a Salmonella typhimurium aspC mutant to sulfometuron methyl, a potent inhibitor of acetolactate synthase II; Van Dyk TK et al.; Sulfometuron methyl is a potent and specific inhibitor of acetolactate synthase II in Salmonella typhimurium . Mutant strains sensitive to sulfometuron methyl on minimal medium were isolated following mutagenesis with Tn10 . A conditionally auxotrophic insertion mutant, strain SMS409, which required aspartate at high temperatures or in the presence of tyrosine, was found among the 15 mutants isolated . The Tn10 insertion in strain SMS409 was mapped by conjugation and transduction to the region between aroA and pncB at 20 min on the chromosome of S . typhimurium; this location is similar to the genetic location of aspC in Escherichia coli . The specific activity of the aspC product, aspartate aminotransferase, was severely reduced in strain SMS409 . This indicated that the Tn10 insertion in strain SMS409 inactivated aspC . An aspC mutant of E . coli was also inhibited by either sulfometuron methyl or tyrosine . We present a hypothesis which relates the observed alpha-ketobutyrate accumulation in sulfometuron methyl-inhibited cultures of strain SMS409 to aspartate starvation.

Proc Natl Acad Sci U S A, 1986 Feb, 83(4), 1026 - 30
Colony probing as an alternative to standard sequencing as a means of direct analysis of chromosomal DNA to determine the spectrum of single-base changes in regions of known sequence; Miller JK et al.; We demonstrate here the means to directly analyze bacterial chromosomal DNA for all classes of single-base mutations in a specific codon in any region of known sequence through the use of DNA probing as a powerful substitute for standard sequencing techniques . With this method, chromosomal DNA from hundreds of mutants can be examined for single-base changes without any DNA cloning . This method can conveniently provide a large data base for the assessment of all classes of single-base mutations occurring spontaneously or induced by a known or suspected mutagen . The method is demonstrated for the analysis of histidine-independent (His+) revertants of hisG46, a missense mutation of Salmonella typhimurium that can revert in six or seven ways.

Mutat Res, 1986 Feb, 173(2), 105 - 9
Isolation, identification and bacterial mutagenicity of 2-nitro-9-fluorenone from diesel-exhaust particle extracts; Bechtold WE et al.; Organic extracts of diesel-exhaust particles show direct mutagenic activity in the Salmonella typhimurium bacterial mutagenicity assay . Nitro-aromatic compounds are believed to be responsible for part of the mutagenicity . A previously unidentified polyfunctional nitro-aromatic compound, 2-nitro-9-fluorenone (2N-Fone) was isolated from diesel-exhaust particles using a two-step fractionation scheme consisting of Sephadex LH20 chromatography and silica-gel thin-layer chromatography . Positive identification was by gas chromatography/mass spectroscopy and coelution with an authentic standard . Direct and indirect mutagenicities of 2N-Fone in several bacterial strains were also determined . The results indicated that 2N-Fone produces 60-70 rev/nmole of direct mutagenic activity, and is about 1/5 to 1/10 as mutagenic as 1-nitropyrene.

Biochemistry, 1986 Jan 28, 25(2), 305 - 12
Glucose-specific permease of the bacterial phosphotransferase system: phosphorylation and oligomeric structure of the glucose-specific IIGlc-IIIGlc complex of Salmonella typhimurium; Erni B; The glucose-specific membrane permease (IIGlc) of the bacterial phosphoenolpyruvate-dependent phosphotransferase system (PTS) mediates active transport and concomitant phosphorylation of glucose . The purified permease has been phosphorylated in vitro and has been isolated (P-IIGlc) . A phosphate to protein stoichiometry of between 0.6 and 0.8 has been measured . Phosphoryl transfer from P-IIGlc to glucose has been demonstrated . This process is, however, slow and accompanied by hydrolysis of the phosphoprotein unless IIIGlc, the cytoplasmic phosphoryl carrier protein specific to the glucose permease (IIGlc) of the PTS, is added . Addition of unphosphorylated IIIGlc resulted in rapid formation of glucose 6-phosphate with almost no hydrolysis of P-IIGlc accompanying the process . A complex of IIGlc and IIIGlc could be precipitated from bacterial cell lysates with monoclonal anti-IIGlc immunoglobulin . The molar ratio of IIGlc:IIIGlc in the immunoprecipitate was approximately 1:2 . Analytical equilibrium centrifugation as well as chemical cross-linking showed that purified IIGlc itself is a dimer (106 kDa), consisting of two identical subunits . These results suggest that the functional glucose-specific permease complex comprises a membrane-spanning homodimer of IIGlc to which four molecules of IIIGlc are bound on the cytoplasmic face.

J Am Vet Med Assoc, 1986 Jan 15, 188(2), 163 - 7
Salmonellosis in hospitalized horses: seasonality and case fatality rates; Carter JD et al.; Salmonellosis was studied during an 11-year period (July 1971 through June 1982) in 245 hospitalized horses . Ten years' data (207 cases) were analyzed in a time series study . Peak seasonality of the disease was from June through September . The cycle curve revealed 3 major outbreaks, with no apparent periodicity . Eighteen Salmonella serotypes caused clinical salmonellosis in horses, but 84% of the cases and 90% of the deaths were caused by 5 serotypes: Salmonella typhimurium, S typhimurium var copenhagen, S anatum, S kottbus, and S saint-paul . Overall, the case fatality rate was 44.9% . Excluding mixed infections, horses infected with S typhimurium and S typhimurium var copenhagen, had a significantly higher (P less than 0.001) case fatality rate (60.4%) than those infected with other Salmonella serotypes (32.3%).

Eur J Biochem, 1986 Jan 15, 154(2), 337 - 41
The phosphoenolpyruvate:glucose phosphotransferase system of Salmonella typhimurium . The phosphorylated form of IIIGlc; Nelson SO et al.; Enzyme IIIGlc of the phosphoenolpyruvate: sugar phosphotransferase system (PTS) of Salmonella typhimurium can occur in two forms: phosphorylated and nonphosphorylated . Phosphorylated IIIGlc (P-IIIGlc) has a slightly lower mobility during sodium dodecyl sulphate/polyacrylamide gel electrophoresis than IIIGlc . In bacterial extracts both phosphoenolpyruvate (the physiological phosphoryl donor of the PTS) as well as ATP can phosphorylate IIIGlc . The ATP-catalyzed reaction is dependent on phosphoenolpyruvate synthase, however, and is due to prior conversion of ATP to phosphoenolpyruvate . The phosphoryl group of phosphorylated IIIGlc is hydrolysed after boiling in sodium dodecyl sulfate but phosphorylated IIIGlc can be discriminated from IIIGlc if treated with this detergent at room temperature . We have used the different mobilities of IIIGlc and P-IIIGlc to estimate the proportion of these two forms in intact cells . Wild-type cells contain predominantly P-IIIGlc in the absence of PTS sugars . In an S . typhimurium mutant containing a leaky ptsI17 mutation (0.1% enzyme I activity remaining) both forms of IIIGlc occur in approximately equal amounts . Addition of PTS sugars such as glucose results, both in wild-type and mutant, in a dephosphorylation of P-IIIGlc . This correlates well with the observed inhibition of non-PTS uptake systems by PTS sugars via nonphosphorylated IIIGlc.

Biochem Biophys Res Commun, 1986 Jan 14, 134(1), 100 - 5
Regioselective glutathione conjugation of the carcinogen, 7, 12-dihydroxymethylbenz{a}anthracene, via reactive 7-hydroxymethyl sulfate ester in rat liver cytosol; Watabe T et al.; Potent mutagenicity of 7,12-dihydroxymethylbenz{a}anthracene (DHBA) toward Salmonella typhimurium TA 98 in the presence of rat liver cytosol fortified with 3'-phosphoadenosine 5'-phosphosulfate (PAPS) was completely retarded by the addition of glutathione (GSH) . The reactive and intrinsically mutagenic metabolite, DHBA 7-sulfate, formed by hepatic cytosolic sulfotransferase disappeared from the incubation mixture by the addition of GSH . Non-mutagenic S-(12-hydroxymethylbenz{a}anthracen-7-yl)methylglutathione was isolated from the incubation mixture consisting of the hepatic cytosol, DHBA, PAPS, and GSH and proved to be formed by GSH S-transferase directly from DHBA 7-sulfate as an obligatory intermediate.

J Biol Chem, 1986 Jan 5, 261(1), 428 - 43
Isolation of differentiated membrane domains from Escherichia coli and Salmonella typhimurium, including a fraction containing attachment sites between the inner and outer membranes and the murein skeleton of the cell envelope; Ishidate K et al.; Cell envelopes of Salmonella typhimurium and Escherichia coli were disrupted in a French pressure cell and fractionated by successive cycles of sedimentation and floatation density gradient centrifugation . This permitted the identification and isolation of several membrane fractions in addition to the major inner membrane and murein-outer membrane fractions . One of these fractions (fraction OML) accounted for about 10% of the total cell envelope protein, and is likely to include the murein-membrane adhesion zones that are seen in electron micrographs of plasmolyzed cells . Fraction OML contained inner membrane, murein, and outer membrane in an apparently normal configuration, was capable of synthesizing murein from UDP-{3H}N-acetylglucosamine and UDP-N-acetylmuramylpentapeptide and covalently linking it to the endogenous murein of the preparation, and showed a labeling pattern in {3H}galactose pulse-chase experiments that was consistent with its acting as an intermediate in the movement of newly synthesized lipopolysaccharide from inner membrane to outer membrane . The fractionation procedure also identified two new minor membrane fractions, with characteristic protein patterns, that are usually included in the region of the major inner membrane peak in other fractionation procedures but can be separated from the major inner membrane fraction and from contaminating flagellar fragments by the subsequent floatation centrifugation steps.

Proc Soc Exp Biol Med, 1986 Jan, 181(1), 163 - 8
Endotoxin inactivating activity of rat serum; Yamaguchi Y et al.; The ability of rat serum to inactivate endotoxin (LPS) was assessed with the aid of the limulus amebocyte lysate assay . Following the addition of various amounts of endotoxin to normal serum the mixture was incubated for 1 hr at 37 degrees C and the residual endotoxin activity determined . One milliliter of rat serum inactivated between 5 and 10 micrograms Escherichia coli LPS per hour . Heating serum for 45 min at 56 degrees C resulted in loss of 80-90% of the LPS inhibitor (LPSI) activity . Serum from cobra venom factor (CVF)-treated rats inactivated between 0.5 and 2.5 micrograms LPS/ml serum . Serum from tolerant rats, even after heating for 45 min at 56 degrees C, inactivates between 10 and 15 micrograms LPS/ml serum/hr; decomplemented tolerant rat serum neutralizes between 5 and 10 micrograms LPS/ml serum/hr . Clearly, the tolerant rat has large quantities of LPSI activity, which does not appear to be complement . The inhibitor found in tolerant rat serum is not species specific since it inactivates Salmonella minnesota and Salmonella typhimurium endotoxins to the same degree and in the same amount as E . coli endotoxin, the agent used to induce tolerance . Both heating serum (56 degrees C) and lead acetate reduce LPSI activity.

IARC Sci Publ, 1986, (70), 413 - 8
Detection and identification of mutagens by the adducts formed upon reaction with guanosine derivatives; Kasai H et al.; Mutagens present in crude samples such as heated glucose can be detected or identified by means of the adducts formed upon reaction with a fluorescent guanosine derivative (FG) or isopropylideneguanosine (IPG) . After the reaction of IPG with heated glucose, two adducts were isolated by high-performance liquid chromatography . One of the adducts was identified as the cyclic adduct formed between IPG and glyoxal . Mesoxaldialdehyde, which is structurally related to glyoxal, also produced a cyclic IPG-adduct and showed mutagenic activity in Salmonella typhimurium strain TA100 . The other adduct isolated from the reaction mixture of IPG and heated glucose was 8-hydroxy-IPG . Various reagents which generate oxygen radicals were effective in the hydroxylation of guanosine derivatives at the C-8 position . These reagents also cause hydroxylation of guanine residues in DNA.

Proc Natl Sci Counc Repub China B, 1986 Jan, 10(1), 20 - 34
Food-borne amines and amides as potential precursors of endogenous carcinogens; Lin JK; This paper reviews the experimental results of our research in the past several years and other related papers that have been directed toward the occurrence, biotransformation and epidemiological significance of carcinogenic N-nitroso compounds in biosphere . Endogenous carcinogens are a group of cancer-causing compounds produced in vivo from harmless precursors . This category has been exemplified by the well-known carcinogens, N-nitroso compounds . The significance of naturally occurring amines and amides as precursors of carcinogenic N-nitroso compounds in vivo and their implication in the incidence of human cancer have been investigated and emphasized . Extremely high levels of trimethylamine-N-oxide and dimethylamine were detected in squids and other seafoods . More than 90% of trimethylamine-N-oxide were converted to dimethylamine and trimethylamine on pyrolysis . Low levels of dimethylamine and methylamine were also detected in the fermented soybean products, wines and sauces . Both dimethylamine and trimethylamine are excellent precursors of dimethylnitrosamine . Several naturally occurring aromatic amines especially 2-carboline derivatives such as harman, norharman, harmaline, harmalol, harmine and harmol are mutagenic and become more mutagenic to Salmonella typhimurium after nitrosation . Appreciable amounts of piperidine were detected in the popular spice white and black pepper powders . Under acidic condition, piperidine reacts readily with nitrite to form carcinogenic N-nitroso-piperidine . N-Nitrosophenacetin was formed from the reaction of nitrite with the amide drug phenacetin . This new compound showed strong mutagenicity to Salmonella typhimurium and Sarcina lutea and strong teratogenic activity to Leghorn chicken embryos . Studies have shown that the majority of N-nitroso compounds in the body come from in vivo conversion . Most investigators believe that this endogenous pool of N-nitroso compounds may prove to be a major exposure route in man . The presence of naturally occurring amines and amides in the diet then becomes one of the crucial limiting steps in the formation of endogenous N-nitroso compounds in vivo.

Chemotherapy, 1986, 32(2), 102 - 12
Autoradiographic evidence for penetration of 3H-ceftriaxone (Rocephin) into cells of spleen, liver and kidney of mice; Kuhn H et al.; Ceftriaxone (Rocephin), a broad-spectrum parenteral cephalosporin with an exceptionally long elimination half-life, has a marked activity against both Salmonella typhimurium infections in mice and typhoid fever in man . This study investigates autoradiographically the penetration of ceftriaxone into murine cells of liver, spleen and kidney, with emphasis on the cells of the reticuloendothelial system (RES) . The RES is an important site of localization of the pathogenic agent of typhoid fever . An incorporation of ceftriaxone was found in several cell types of the three investigated organs, in particular the cells of the RES and in precursors, e.g . monocytes of the blood stream, Kupffer cells or reticular cells . Besides long biological half-life, satisfactory penetration into phagocytes and other tissue cells has been shown, which is essential to the good in vivo activity of ceftriaxone against systemic Salmonella infections.

Beitr Trop Landwirtsch Veterinarmed, 1986, 24(4), 431 - 5
Viability of Salmonella typhimurium in different environmental conditions (feed, litter; temperature); Nashed SM; In countries with a prevailing poultry production, salmonellosis is of growing importance . The poultry contaminated with salmonellae plays a significant role in the food poisoning of men and in decreasing the breeding results . The study investigated the viability of Salmonella typhimurium in feed and litter contaminated with this germ, at different temperatures . The organism remained viable at 37 degrees C in feed up to 6 weeks, in litter for 2 weeks, at room temperature in the feed up to 71 weeks in the litter up to 78 weeks, and at 7 degrees C in feed and litter up to 79 weeks . Recommendations are given for the control of salmonellosis by referring to the sources and possibilities of contamination.

Nucleic Acids Symp Ser, 1986, (17), 141 - 3
Synthesis of a mutagenic nucleoside, 2'-deoxy-2-(p-nitrophenyl)-adenosine; Matsuda A et al.; The reaction of 2-amino-6-chloropurine riboside with i-amyl nitrite in benzene in the presence of Cu2O, followed by treatment with NH3/MeOH gave 2-phenyladenosine (1) . The crude sample of 1 was found to be mutagenic to bacteria (Salmonella typhimurium TA 98 and TA 100, without metabolic activation) . When this material was subjected to high pressure liquid chromatography, the mutagenic activity was found only in contaminating minor components, whose structures were assigned as 2-(m- and p-nitrophenyl)-adenosines (2m,p) . In order to study structure-activity relationships, several nucleoside and base analogues were synthesized . Among them, 2'-deoxy-2-(p-nitrophenyl)-adenosine (8) was the most potent mutagen as tested either with TA 98 or TA 100.

Gene, 1986, 47(2-3), 231 - 44
The organization of the araBAD operon of Escherichia coli; Lee N et al.; The nucleotide (nt) sequence of the araBAD operon of Escherichia coli B/r has been determined . The nt sequence predicts a transcript of about 4250 nt . The coding regions of araB, araA and araD genes were identified by partial amino acid (aa) sequences of the purified proteins and their cleavage products . We have deduced that the polypeptides encoded by the araBAD operon consist of 566 (araB), 500 (araA) and 231 (araD) aa residues . The operon contains a leader sequence of 27 nt . The intergenic region between araB and araA is 10 bp in length, while the araA and araD genes are separated by 283 bp consisting primarily of six REP sequences . Comparison of the E . coli sequence with that of Salmonella typhimurium {Lin et al., Gene 34 (1985) 111-122; 123-128; 129-134} shows that, while considerable divergence in nt sequence has occurred, the aa sequences are largely conserved . The most pronounced difference, found in the araD gene, is the deletion of a single nt in the S . typhimurium sequence.

Arch Toxicol Suppl, 1986, 9, 425 - 9
Structure-activity relationship of nitroimidazo (2,1-b) thiazoles in the Salmonella mutagenicity assay; Biagi GL et al.; The mutagenic activity of a series of nitroimidazo (2,1-b) thiazoles was determined in Salmonella typhimurium TA-100 strain by means of the Ames test . A multiple regression analysis showed a highly significant parabolic relationship between mutagenic activity and the Rm values as an expression of the lipophilic character of molecules . The lipophilic character should be important in determining an optimal cell permeation . However when the lipophilic character was expressed by means of the sigma pi values the equation was much less satisfactory . This could be due to the fact that the Rm values of nitroheterocyclic compounds actually represent a measure both of lipophilic and polar character.

Scand J Infect Dis, 1986, 18(6), 551 - 2
Food poisoning outbreak in Ibadan, Nigeria, due to a new phage type of Salmonella typhimurium; Ojeniyi AA et al.; An outbreak of food poisoning in Ibadan, Nigeria, claimed about 20 lives . A new phage type U282 of Salmonella typhimurium, the causative organism, was isolated from a sandwich filling, which yielded 4 X 10(9) viable organisms/g . The sandwiches were prepared in Lagos and kept without refrigeration until consumption next day . There is need for stricter control in the tropical developing countries of private catering agencies which imitate those of the advanced industrial countries.

Mem Inst Oswaldo Cruz, 1986 Jan-Mar, 81(1), 49 - 52
CL 64,855, a potent anti-Trypanosoma cruzi drug, is also mutagenic in the Salmonella/microsome assay; Ferreira RC et al.; The nitroimidazole-tiadiazole derivative CL 64,855 (2-amino-5-(1-methyl-5-nitro-2-imidazolyl)-1,3,4-thiadiazole, a potent anti-trypanosomal drug, was assayed in a short-term bacterial mutagenicity test with Salmonella typhimurium strains TA 98, TA 100 and TA 102 . Results indicate that CL 64,855 is a potent frameshift mutagen detected by strains TA 98 and TA 102 . CL 64,855 was able to revert the indicators strains at concentrations as low as 0.1 micrograms/plate . Metabolic activation experiments with rat liver microsomal fractions did not increase the mutagenic action of CL 64,855.

IARC Sci Publ, 1986, (70), 293 - 7
Evaluation of the mutagenicity of 1,N6-ethenoadenine- and 3,N4-ethenocytosine-nucleosides in Salmonella typhimurium; Negishi K et al.; To provide supporting evidence for the hypothetical involvement of etheno-derivative formation in DNA in chloroacetaldehyde-mediated mutagenesis, etheno nucleosides were examined for their direct-acting mutagenicity in Salmonella typhimurium strain TA100 . The results, however, have shown that 1,N6-ethenoadenosine, 1,N6-ethenodeoxyadenosine, 3,N4-ethenocytidine and 3,N4-ethenodeoxycytidine lack mutagenicity in this test system . A lesson learned in this study is that 3,N4-ethenocytosine nucleosides prepared synthetically or obtained from commercial sources can give false positive mutagenicity due to mutagenic contaminants.

IARC Sci Publ, 1986, (70), 283 - 91
Methylglyoxal in beverages and foods: its mutagenicity and carcinogenicity; Nagao M et al.; Methylglyoxal was found to induce mutations in Salmonella typhimurium strains TA100, TA102 and TA104, gene conversion in Saccharomyces cerevisiae strain D7, and diphtheria toxin resistance mutation in Chinese hamster lung cells . Methylglyoxal was detected in coffee, whiskey, a soft drink, toasted bread and soy sauce . The mutagenicity of methylglyoxal was suppressed by sulfite, cysteine, glutathione and dithiothreitol, and enhanced by hydrogen peroxide . Methylglyoxal induced sarcomas in rats at the site of its subcutaneous injection.

Environ Mutagen, 1986, 8(6), 829 - 37
Mutagenicity of N-substituted phenanthrene 9,10-imines in Salmonella typhimurium and Chinese hamster V79 cells; Glatt H et al.; We previously showed that some (nonsubstituted) aziridines derived from polycyclic aromatic hydrocarbons (arene imines) elicit various mutagenic and genotoxic effects in bacteria and mammalian cells and that these arene imines are active at much lower concentrations than the corresponding epoxide analogues . In the present study, N-substituted derivatives of phenanthrene 9,10-imine were investigated . All 10 derivatives studied showed direct mutagenicity in Salmonella typhimurium TA100 . Some of the compounds additionally exhibited weak effects in the strains TA98 and TA1537 . Most N-substituted derivatives were weaker mutagens than unsubstituted phenanthrene 9,10-imine but stronger mutagens than phenanthrene 9,10-oxide . Bulky substituents reduced the mutagenicity more than did small substituents . In addition, the derivatives with electron-withdrawing substituents (with the exception of N-chlorophenanthrene 9,10-imine) were weaker mutagens than those with electron-donating substituents . Phenanthrene 9,10-imine and five N-substituted derivatives were investigated to determine whether they induce gene mutations at the hgprt locus in V79 cells . Four compounds, including the parent aziridine, were positive in the V79 test . The other two compounds were negative . The mutagenic potencies in the V79 cell system did not correlate well with those obtained with the Salmonella system . Overall, the study shows that in addition to unsubstituted arene imines, N-substituted derivatives are mutagenic . This finding is of interest, as metabolic pathways leading from aromatic compounds to N-substituted arene imines are conceivable.

Environ Mutagen, 1986, 8(6), 797 - 815
Effects of excision repair and plasmid pKM101 on mutagenic and cytotoxic potencies of anthracycline derivatives in test strains of Salmonella typhimurium; Thomas HF et al.; The effects of excision repair and presence of plasmid pKM101 on the mutagenicities and cytotoxicities of the anthracycline derivatives Adriamycin, daunomycin, carminomycin, and 4-demethoxydoxorubicin were examined in strains of Salmonella typhimurium . Plasmid pKM101 has been shown to mediate inducible error-prone repair in S . typhimurium . While the test compounds were shown to produce a range of mutational responses in excision repair defective (uvrB-), pKM101-bearing strains of different his- backgrounds, proficiency in excision repair generally resulted in the elimination of mutagenic responses in all such strains except those that contain the hisG428 site . In the absence of pKM101, only hisD3052 uvrB- strain TA1538 was shown to be sensitive to anthracycline mutagenicity . A suspension (preincubation) test as well as a direct plating test showed that while proficiency in either excision repair (uvr+) or plasmid pKM101 error-prone repair afforded cellular protection against anthracycline cytotoxicity, plasmid-free uvrB- strains were most sensitive to anthracycline cytotoxicity.

Int Arch Occup Environ Health, 1986, 58(3), 227 - 34
A fraction of beech wood mutagenic in the Salmonella/mammalian microsome assay; Mohtashamipur E et al.; Base-pair substitution mutagens were isolated from the dusts of several untreated samples of beech wood and tested for mutagenicity in the Salmonella/mammalian microsome assay . These compounds reverted Salmonella typhimurium his- TA 100 in the presence of Aroclor-induced rat S9 . These mutagens were found to be toxic to the cells when tested in a histidine-rich medium (complete medium) . Mutagenicity of the non-fractionated wood-dust extracts due to the presence of some inhibitory compounds of wood could not be confirmed significantly . These inhibitors counteracted the reversion of bacteria when the known mutagens, such as benzo(a)pyrene, aflatoxin B1 and ethyl methanesulfonate, were tested . The results indicate that beech wood-dust contains mutagenic constituent(s) which may contribute to their assumed tumor bearing effects among wood-workers.

Environ Mutagen, 1986, 8(5), 741 - 51
A protocol for the combined biochemical and serological identification of the Ames mutagen tester strains as Salmonella typhimurium; Busch DB et al.; Previously published reports have noted biochemical reactions atypical of Salmonella among the Ames tester strains of Salmonella typhimurium, and an inability to assign the strains to a specific Salmonella O (heat-stable cell wall) antigen group . We studied the biochemistry and serology of strains TA97, 98, 100, 102, 104, 1535, 1537, and 1538 in an attempt to develop a protocol to correctly speciate the strains . Biochemical reactions of all eight strains using standard media supplemented with histidine and biotin were consistent with those of the genus Salmonella . Strains TA100, 104, and 1535 were assigned to Salmonella O groups using bacteria treated with hot ethanol (White schema) . H (flagellar) antigen assignments were performed successfully with seven of the eight strains . Two H antigen assignments required the use of the Craigie tube test for selection of motile revertants . Combining our biochemical and serological results obtained by this protocol, we were able to correctly speciate TA100, 104, and 1535 as Salmonella typhimurium . Our results demonstrate that representatives of the tester strains can be correctly speciated provided that procedures are followed that allow for the unusual nutrient requirements, the deep rough cell wall mutation, and the variably deficient motility of these organisms.

Environ Mutagen, 1986, 8(5), 717 - 25
Chromium (VI) comutagenesis: characterization of the interaction of K2CrO4 with azide; LaVelle JM; In a previous report chromate potentiated the mutagenicity of sodium azide, apparently by affecting repair and/or replication of DNA . Further evidence in support of such a mechanism for chromate potentiation is reported here . Chromate does not react directly with azide or its major mutagenic metabolite, azidoalanine, eliminating such reactions as possible mechanisms for potentiation . Further, azide was unable to potentiate the mutagenicity of chromate in Salmonella typhimurium strain TA104, which is sensitive to chromate mutagenicity but not to azide . Thus, it appears that the potentiation is not due to an action of azide in modulating chromate mutagenicity . Finally, the interaction was not altered by deficiency in recA gene product in S typhimurium GW19, nor by enhancement of SOS repair in the pKM101 containing strain TA100 . Thus, induction of recA-dependent functions seems to play no role in the comutagenic actions of chromate . The simplest explanation for potentiation seems to be that chromate is able either to limit error-free recovery from azide-induced DNA damage or to promote error-prone repair or error-prone processing at sites of lesions.

Environ Mutagen, 1986, 8(5), 675 - 92
Genetic and physiological modulation of anthracycline-induced mutagenesis in Salmonella typhimurium; Cebula TA; The genotoxic properties of adriamycin and daunomycin, anthracycline antibiotics effective in the treatment of a wide variety of malignancies, were examined in the Salmonella/Ames reverse-mutation test . A novel time- and temperature-dependent phenomenon that potentiates the mutagenicity of these compounds, termed mutational enhancement, is described . The results of congeneric and chemical attenuation studies imply that anthracycline-induced free radicals contribute substantively to the mutagenic potentials of adriamycin and daunomycin . These studies show that adriamycin and daunomycin are not simple intercalative compounds . Rather, anthracycline-induced mutagenesis entails at least two separate but intimately related steps, namely, intercalation within discrete base sequences and the free-radical-mediated events that ensue . Implications of the nonrandom and site-specific action of the anthracyclines are discussed.

Environ Mutagen, 1986, 8(5), 659 - 73
Glutathione: a protective agent in Salmonella typhimurium and Escherichia coli as measured by mutagenicity and by growth delay assays; Owens RA et al.; Cultures of some aerobically grown strains of Salmonella typhimurium and Escherichia coli contain up to 24 microM extracellular glutathione (GSH) {Owens RO, Hartman PE (1985): Environ Mutagen 7(Suppl 3): 47} in addition to having intracellular GSH concentrations in the millimolar range . The addition of 26 microM GSH to cultures of Salmonella typhimurium strain TA1534 partially protected the bacteria from the toxic effects causing growth delay by 54 microM N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) . When MNNG was preincubated with equimolar GSH, the mutagenicity of the MNNG was neutralized . The addition of micromolar GSH to cultures of an Escherichia coli GSH- strain protected the cells from growth inhibition by micromolar concentrations of mercuric chloride, methyl mercuric chloride, silver nitrate, cisplatin, cadmium chloride, cadmium sulfate, and iodoacetamide . In the cases of mercuric chloride, cisplatin, MNNG, silver nitrate, and iodoacetamide, reaction products with GSH were detected by paper chromatography . In contrast to reduced GSH, micromolar concentrations of oxidized glutathione (GSSG) provided little or no protection and formed no detectable reaction products . Export of GSH by enteric bacteria may provide an important defense mechanism against exogenous toxic agents otherwise active in the micromolar range.

Microbiol Immunol, 1986, 30(5), 425 - 35
Increased resistance to Salmonella infection of hypoferremic mice fed a low-protein diet; Gauthier Y et al.; BALB/c and CBA/CA mice fed a protein-deficient diet developed a plasma hypoferremia corresponding to a 30 percent lowering of serum iron concentration . This hypoferremia persisted as long as the diet was maintained . Hypoferremic CBA/CA mice had increased resistance to Salmonella typhimurium C5 infection, as shown by the reduced lethal activity and the decreased growth of the bacteria in the spleen and in the peritoneal exudate of the deficient animals . This induced resistance was abolished after injection of iron or Desferal into the restricted animals . Such resistance was not observed with BALB/c mice fed a protein-deficient diet, in spite of the plasma hypoferremia . The growth of S . typhimurium C5 in the spleen and in the peritoneal exudate of these animals did not differ from the growth observed in control animals fed a protein-sufficient diet . This study suggests that hypoferremia induced by a protein-deficient diet is probably involved in the enhancement of resistance of CBA/CA mice to Salmonella infection, and that the phenomenon is host-strain dependent.

Int Arch Allergy Appl Immunol, 1986, 81(1), 24 - 30
Genetic control of delayed-type hypersensitivity in mice to Salmonella antigen; Cho N et al.; Genetic restriction on the expression of delayed-type hypersensitivity (DTH) to Salmonella typhimurium in mice transferred passively with immune spleen cells was studied . After the intravenous transfer of immune C3H/HeJ (H-2Ik) cells into A.TL (H-2Ik) or A.TH (H-2Is) mice, footpad DTH responses could be evoked in the A.TL recipients, but not in the A.TH mice . When the immune cells of BALB/c or C3H/He mice were intravenously-transferred into F1 hybrids produced by mating BALB/c and C57BL/6 or C3H/He and C57BL/6, respectively, no DTH response could be evoked in these F1 hybrids that received immune parental cells . Local transfer as well as systemic intravenous transfer of immune parental cells to F1 haplotype recipients did not cause any DTH . Previous treatment of the F1 hybrid recipients with cyclophosphamide did not result in the expression of the DTH response . Transfer of immune F1 spleen cells into parental strains also did not induce DTH . When the immune cells of parental strains were transferred into F2 mice and into back-cross mice, examination of the DTH response in these mice showed that some of them did not have any obvious footpad swelling, while others revealed various magnitudes of swelling . The resistance of F1 hybrids to transfer of DTH is discussed.

Nutr Cancer, 1986, 8(3), 201 - 10
Nonmutagenicity of curcumin and its antimutagenic action versus chili and capsaicin; Nagabhushan M et al.; Turmeric, which is one of the commonly used spices in Indian cooking, was tested for mutagenicity using the Ames test . The alcoholic extract of fresh or dried turmeric, its principal components, and pyrolyzed turmeric powder and curcumin were tested for mutagenicity in Salmonella typhimurium strains with and without metabolic activation . None of these were mutagenic in all the tester strains . Chilies (which are used with turmeric powder) and their principal alkaloid capsaicin were mutagenic in the TA 98 with S9 mixture . We tested curcumin, which is the principal component of turmeric, for its antimutagenic effect . It showed dose-dependent decreases in mutagenicity of chili extract and capsaicin . Also, we compared the antimutagenicity of curcumin with other known antioxidants, including BHA, vitamins E and C, and vegetable oils . These all showed dose-dependent decreases in mutagenicity of chili extract and capsaicin . These studies show that although there are few mutagenic principles in Indian food, there is still quite a large number of antimutagenic principles in the Indian diet that will modulate the activity of environmental mutagens.

Microbios, 1986, 45(184-185), 209 - 12
Production of colicin E5 by epidemic strains of Salmonella typhimurium var . Copenhagen; Afrasiabi SN et al.; Sixty eight strains of Salmonella typhimurium were isolated during an outbreak of salmonellosis in the paediatric ward of Saadi hospital in Shiraz, Iran . Eleven of the strains were shown to produce a single type of colicin of group E . This colicin was identified as colicin E5 . Most of the colicinogenic strains exhibited similar drug sensitivity and phage typing patterns and all were of the serotype S . typhimurium var . Copenhagen.

J Cancer Res Clin Oncol, 1986, 111(3), 209 - 19
Synthesis, antitumor activity, distribution and toxicity of 4-{4-{bis(2-chloroethyl)amino}phenyl}-1-hydroxybutane-1 1-bisphosphonic acid (BAD), a new lost derivative with increased accumulation in rat osteosarcoma; Wingen F et al.; The aim of this study was to investigate whether the newly synthesized bisphosphonic acid-linked N-Lost derivative BAD retains bone-seeking and cytostatic properties . The paper describes experiments on mutagenicity in vitro and on toxicity in vivo . BAD is characterized by very low mutagenic activity toward histidine auxotrophic Salmonella typhimurium strains . Cytotoxic effects were tested in rat osteosarcoma and in Walker carcinosarcoma 256B . The LD50 of i.v . injected BAD was 146 mg/kg . Acute toxicity is probably caused by calcium complexing of the bisphosphonate part of the molecule . Labeling experiments showed moderate accumulation in bone and osteosarcoma, as well as in lung metastases . BAD effected high tumor growth inhibition in osteosarcoma and Walker carcinosarcoma-bearing rats and marked prolongation of survival; histologic and radiographic examination revealed rapid calcification of osteosarcoma and lung metastases . BAD-pretreatment produced protective effects against osteolysis induced by intratibially implanted Walker carcinosarcoma ascites cells . The cytostatic efficacy of equitoxic doses of BAD in rat osteosarcoma is comparable to that of dacarbazine and in Walker carcinosarcoma to that of melphalan.

Environ Mutagen, 1986, 8(4), 627 - 30
NPPD (spy dust) is predicted to be a mutagen; Klopman G et al.; With the aid of CASE, the Computer Automated Structure Evaluation system, a new artificial intelligence procedure to study structure-activity relationships and a data base consisting of 233 monocyclic nitroarenes, it is predicted that 5-(4-nitrophenyl)-2,4-pentadienal will be mutagenic for Salmonella typhimurium but that the activity will be very low.

Environ Mutagen, 1986, 8(4), 611 - 9
Mutagenicity study on pyrazole, seven pyrazole derivatives, and two nitroimidazoles with the L-arabinose resistance test of Salmonella typhimurium; Alejandre-Duran E et al.; The mutagenicity of pyrazole and seven pyrazole derivatives (4-nitropyrazole, 4-bromopyrazole, 1-methyl-4-nitropyrazole, 3,5-dimethyl-4-nitropyrazole, 1-methyl-4-bromopyrazole, 4,4'-dinitro-1, 1'-methylene-dipyrazole and 4,4'-dibromo-1,1'-methylene-dipyrazole) has been investigated with the L-arabinose forward mutation assay of Salmonella typhimurium . Two nitroimidazoles (1-methyl-5-nitroimidazole and metronidazole) were included as reference drugs . The mutagenicity of each chemical was determined by both preincubation and liquid tests, in the presence or absence of S9 microsomal fraction . The mutagenic response was expressed as the absolute number of L-arabinose resistant mutants growing in selective plates, supplemented with traces of D-glucose . Strain BA13 with a wildtype lipopolysaccharide barrier was used as a comparison to the deep rough derivative BA9 . No mutagenic effect was detected with pyrazole and two of its derivatives, 1-methyl-4-bromopyrazole and 4,4'-dibromo-1,1'-methylene-dipyrazole . The other five pyrazole derivatives were mutagenic to different degrees, although their mutagenic potencies were always considerably lower than those of the two nitroimidazoles . The results suggest that 4-nitropyrazoles, as well as 4,4'-dinitro-1, 1'-methylene-dipyrazoles, should be investigated further as alternatives to, or even substitutes for, the currently used nitroimidazoles.

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