Salmonella typhimurium

Mutat Res, 1983 May, 120(2-3), 91 - 5
Are econazole, miconazole and clotrimazole mutagenic to bacteria?
Voogd CE, van der Stel JJ.
The fungistatic drugs econazole, miconazole and clotrimazole were investigated as to mutagenic properties in the fluctuation test with Klebsiella pneumoniae and Escherichia coli K12 as test organisms and in the plate-incorporation test, with and without metabolic activation, with Salmonella typhimurium strains TA98 and TA100 . No mutagenic activity of the 3 compounds on these microorganisms was found.

Mutat Res, 1983 May, 109(2), 183 - 93
The correlation between benzo{a}pyrene-induced mutagenicity and DNA adduct formation in Salmonella typhimurium TA100; Arce GT et al.; In an attempt to stabilize the dose response in the Salmonella typhimurium test (STT), the use of DNA-bound products from BP was evaluated as a measure of the biologically effective dose . In addition to the previously documented interlaboratory variation, we observed a 3-fold difference in the dose response of TA100 to BP even when the assay was repeated with the same experimental conditions . When overall BP-DNA adduct formation was related to the level of His+ revertants, a series of responses emerged with two predominating . In the first type of response around 70 revertants per plate were generated for every BP molecule bound per 10(6) nucleotides of cellular DNA . The second response gave about 1400 revertants per plate for one BP bound in every 10(6) nucleotides . Several intermediates curves were also detected . The variation in the mutational response to binding levels occurred regardless of the source of S9 or the growth stage of the cells . These experiments indicate that there was no constant level of DNA damage that would lead to a specified number of revertants of TA100 by BP and that DNA modification was not solely responsible for mutagenic potency . It is possible that an induction of an error-prone repair function of the muc gene carried by the plasmid pKM101 in TA100 may be affecting the relationship between the measured adduct level and reversion frequency.

J Bacteriol, 1983 May, 154(2), 763 - 71
Isolation and characterization Salmonella typhimurium mutants lacking a tripeptidase (peptidase T); Strauch KL et al.; Salmonella typhimurium contains an enzyme, peptidase T, that hydrolyzes a variety of tripeptides . Specificity studies with a peptidase activity stain after gel electrophoresis of crude cell extracts showed that peptidase T hydrolyzes tripeptides containing N-terminal methionine, leucine, or phenylalanine . Little or no activity could be detected against dipeptides, N-blocked or C-blocked tripeptides, and tetrapeptides . Analysis of reaction products by high-pressure liquid chromatography showed that peptidase T removes the N-terminal amino acid from tripeptides . Mutants lacking peptidase T were isolated by screening microcultures grown in the wells of plastic microtitration plates for hydrolysis of Met-Ala-Ser or Met-Gly-Gly . Mutations (pepT) that eliminate this enzyme were found to be phage P22 cotransducible with purB at approximately 25 map units on the S . typhimurium map . Comparison of the growth properties of mutant and wild-type strains suggests that peptidase T does not function in utilization of tripeptides to provide amino acids during growth.

Cancer Res, 1983 May, 43(5), 2052 - 8
Formation of DNA adducts in vitro and in Salmonella typhimurium upon metabolic reduction of the environmental mutagen 1-nitropyrene; Howard PC et al.; The polycyclic nitroaromatic hydrocarbon 1-nitropyrene is an environmental pollutant, a potent bacterial mutagen, and a carcinogen . Xanthine oxidase, a mammalian nitroreductase, catalyzed the in vitro metabolic activation of this compound to DNA-bound adducts . Maximum adduct formation occurred at pH 5.5 to 6.0 and was increased by the addition of catalase to the incubation medium . DNA binding from 1-nitropyrene was inhibited by hydrogen peroxide, L-ascorbate, and glutathione . Enzymatic hydrolysis of the modified DNA and subsequent analysis by high-pressure liquid chromatography indicated the presence of one major and two minor adducts . The major adduct was characterized by mass spectrometry and nuclear magnetic resonance spectroscopy as N-(deoxyguanosin-8-yl)-1-aminopyrene . The minor adducts appear to be decomposition products of the major adduct . When Salmonella typhimurium TA1538 was incubated with 1-nitropyrene, a strong correlation was found between the extent of DNA binding and the frequency of induced histidine reversions . Analysis of the bacterial DNA indicated one major adduct which had chromatographic properties and pKaS identical to those of N-(deoxyguanosin-8-yl)-1-aminopyrene . These data indicate that N-hydroxy-1-aminopyrene is probably the mutagenic and DNA-binding species formed during the metabolic reduction of 1-nitropyrene.

J Bacteriol, 1983 May, 154(2), 561 - 8
Regulation of proline utilization in Salmonella typhimurium: characterization of put::Mu d(Ap, lac) operon fusions; Maloy SR et al.; The genes for proline utilization were fused to the structural genes of the lac operon by use of the hybrid Mu phage derivative Mu d(Ap lac) . Stable deletion derivatives of these fusions were selected and used to study the transcriptional regulation of the put genes . Analysis of these fusions showed that the putA gene product, a bifunctional oxidase-dehydrogenase, also serves to negatively control transcription of the putA and putP genes . Transcription of the put genes is repressed only in putA+ strains; this repression is lifted when exogenous proline is supplied . Transcription of the put genes is stimulated by cyclic AMP in putA+ and putA strains . Maximal induction of the put genes in putA+ strains requires oxygen or an alternative electron acceptor . This oxygen effect is mediated by the putA protein since putA mutants show maximal transcription even without an electron acceptor . The orientation of the Mu d(Ap lac) insertions was determined by formation of Hfr's via the lac homology on F'ts114 lac+ . The direction of chromosome mobilization by these Mu d(Ap lac)-directed Hfr's demonstrated that the putP and putA genes are divergently transcribed from a central regulatory region lying between them.

J Mol Biol, 1983 Apr 15, 165(3), 443 - 59
DNA sequence changes of mutations in the histidine operon control region that decrease attenuation; Barnes WM et al.; The DNA sequence changes of 18 (9 different) mutations in the control region of the histidine operon of Salmonella typhimurium are presented . All of these mutations increase the level of expression of the operon, presumably by decreasing transcription termination at the attenuator . Five of the mutations were previously isolated hisO mutations, and the other four were isolated here as His+ pseudorevertants of His- stop codon mutations in the leader peptide gene . Only two mutations, O1242 and O3154, directly affect the terminator stem of the leader RNA . One mutation, O1202, creates a strong new stem that would compete with the terminator stem . Most of the other mutations damage other RNA stems . Their effect can best be explained by, and they thus provide supporting evidence for, the prevailing model of attenuator regulation involving alternative, competing RNA stems in the leader RNA . Two mutations that do not appear to significantly affect an RNA stem directly, including a deletion of three of the seven consecutive histidine codons, are best explained as effects of a translating ribosome upon the RNA stem structures, even though the histidine codons are not translated in the pseudorevertants.

Science, 1983 Apr 8, 220(4593), 201 - 4
Fibronectin binds to some bacteria but does not promote their uptake by phagocytic cells; Van de Water L et al.; The involvement of plasma fibronectin in phagocytosis of bacteria was investigated by testing the binding of fibronectin to several species of bacteria and by evaluating the ability of fibronectin to promote binding and endocytosis of two species of these bacteria by phagocytic cells . Fibronectin binds non-covalently to Gram-positive and Gram-negative bacteria and to yeast but did not appear to be necessary or sufficient for uptake of Staphylococcus aureus and Salmonella typhimurium by several different phagocytic cell types.

J Toxicol Environ Health, 1983 Apr-Jun, 11(4-6), 971 - 80
Detection of nitroaromatic compounds on coal combustion particles; Hanson RL et al.; Mutagenic and nonmutagenic extracts of fly ash from fluidized bed combustion were analyzed to determine the compounds responsible for the direct mutagenic activity (mutagenic activity that does not require added metabolic enzymes in the Salmonella mutagenicity assay) . Some nitro derivatives of polycyclic aromatic hydrocarbons which are direct acting mutagens were detected by tandem triple quadrupole mass spectrometry . Treatment of a mutagenic and a nonmutagenic extract with excess N2O4 resulted in 28- and 3200-fold increases, respectively, in direct mutagenicity in Salmonella typhimurium strain TA98 and an increase in the relative abundance of nitroaromatic compounds . Polycyclic aromatic compounds were also detected and tentatively identified by gas chromatography-mass spectrometry . Since, previous studies have shown that polycyclic aromatic hydrocarbons may react with NO2 to form direct-acting mutagens, it appears that the direct-acting mutagens in these fly ash extracts may be products of reactions of polycyclic aromatic hydrocarbons with NOX in the combustion gases.

Cancer Lett, 1983 Apr, 18(3), 271 - 5
Mutagenicity of N-nitrosobis(2-hydroxypropyl)amine and its related compounds in the presence of rat lung and liver S9; Mori Y et al.; The mutagenic activities of N-nitrosobis(2-hydroxypropyl)amine (BHP) and its related compounds were studied in Salmonella typhimurium TA100 and TA98 strains by Ames's liquid incubation assay in the presence or absence of lung and liver S9 of rats treated with polychlorinated biphenyl (PCB) . BHP and its related compounds, N-nitroso-(2-hydroxypropyl)(2-oxopropyl)amine (HPOP), N-nitrosobis(2-oxopropyl)amine (BOP), N-nitrosobis(2-acetoxypropyl)amine (BAP), and N-nitroso-2,6-dimethylmorpholine (NDMM) showed negative mutagenicity in the absence of lung and liver S9 in TA100 and TA98 strains while those compounds showed positive in the presence of liver S9 in TA100 strain . HPOP and BOP showed positive mutagenic activity in the presence of lung S9 in TA100 strain . HPOP showed the strongest mutagenic activity in the presence of lung and liver S9.

Ann Ophthalmol, 1983 Apr, 15(4), 321 - 2
Endogenous endophthalmitis due to Salmonella typhimurium; Shohet I et al.; Endogenous endophthalmitis due to Salmonella typhimurium is reported in a 1-year-old child . Despite vigorous antibiotic therapy, the child's vision deteriorated, and loss of light perception occurred in the infected eye . Endophthalmitis is a very rare complication of salmonellosis, and it should alert physicians because of its severe damage to the eye.

J Appl Physiol, 1983 Apr, 54(4), 1167 - 71
Reproducibility of cardiopulmonary effects of different endotoxins in the same sheep; Traber DL et al.; This study compares qualitative and quantitative differences between the cardiopulmonary responses to Salmonella typhimurium and Escherichia coli 055:B5 endotoxins (Difco) in the same sheep model . Lipopolysaccharides, 0.75 micrograms/kg, were infused into chronically instrumented sheep over 30 min . Cardiopulmonary and pulmonary lymph flux data were collected for 2 h prior to and 6 h following this . One week later the sequence was repeated with another endotoxin . The administration of the two endotoxins was varied: some received S . typhimurium first; others received E . coli . A total of 13 animals were studied; 8 had intact pulmonary lymphatic catheters . Following each injection of endotoxin these animals showed a typical response of early high pressure-mediated increase in pulmonary lymph flow and later lymph flow elevation associated with a very mild increase in microvascular pressure and lymph with normal protein levels . These changes were associated with hemoconcentration, lowered arterial oxygen partial pressure, cardiac index, and blood neutrophil count . It is concluded that Difco S . typhimurium and E . coli endotoxins are similar in their mechanism of action and potency and can be studied in the same animal.

Mutat Res, 1983 Apr, 120(1), 7 - 11
Mutagenicity and co-mutagenicity of catechol on Salmonella; Yoshida D et al.; Catechol was not mutagenic for Salmonella typhimurium TA98, TA100 or TA1537 in the presence or absence of S9 mix . At the lower level of S9 in the Ames method, the mutagenic activity of benzo{a}pyrene decreased with the increased addition of catechol . When catechol was added to the pre-incubation mixture at a higher concentration than in the conventional Ames method, the mutagenic activity of benzo{a}pyrene increased with the increased addition of catechol . Catechol is believed to be a co-mutagen for benzo{a}pyrene in the presence of a sufficient amount of S9 in the incubation mixture.

Mutat Res, 1983 Apr, 117(1-2), 93 - 104
Determining the mutagenic activity of a tar, its vapors and aerosols; Penalva JM et al.; The Ames test was performed on Salmonella typhimurium, strain TA98, TA100, TA1535, TA1537, TA1538, to evaluate the mutagenic potential of a tar as well as its vapors and aerosols emitted at 250, 350 and 550 degrees C . Two chemical procedures were used: extractions of aromatics for DMSO; elimination of acids, alcohols and phenols . Weak mutagenic activity was demonstrated at each temperature . Then, using only Salmonella typhimurium strains TA98 and TA100, a study was made on the effects of the mutagenic compounds, benzo{a}pyrene, 2-aminoanthracene, nitrofluorene, methyl methanesulfonate and on the vapors and aerosols emitted at 350 degrees C by road-coating tar . For promutagenic compounds, an enhancing effect was observed before an inhibition effect . For direct mutagenic compounds, only the inhibition effect appeared . The mutagenic and/or carcinogenic activity was usually tested on a pure isolated chemical compound.

Mutat Res, 1983 Apr, 117(1-2), 47 - 54
Mutagenicity of methyl nitrite in Salmonella typhimurium; Tornqvist M et al.; Methyl nitrite was tested for mutagenicity in Salmonella typhimurium TA1535 . In the first set of experiments, plated bacteria were exposed to methyl nitrite in desiccators both in the absence and presence of a metabolizing system (S9 from Aroclor-pretreated Sprague-Dawley rats) . Initial concentrations from 125 to 500 ppm were tested . In all experiments an increased initial concentration gave an increased mutagenic response . The mutagenic effect in the presence of S9 was similar to that in the absence of S9 . Owing to difficulties in dose determinations in this type of experiment it could not be decided, unequivocally, whether the mutagenic effect was caused by methyl nitrite or its hydrolysis products . Experiments were therefore carried out in suspension, and the concentrations of methyl nitrite and inorganic nitrite were determined . Treatments with inorganic nitrite were also carried out under similar conditions . From the results of these experiments we concluded that methyl nitrite is mutagenic . Possible mechanisms of action of methyl nitrite are discussed, and it is suggested that mutagenicity may be a general property of alkyl nitrites.

Mutat Res, 1983 Apr, 117(1-2), 41 - 6
Mutagenicity in Salmonella typhimurium TA98 of the serum extract of the organic matter derived from airborne particulates; Takeda N et al.; To investigate the interactions between mutagens and serum components, the mutagenicity of the serum extract of the organic matter derived from airborne particulates (tar) was examined by the Salmonella/mammalian microsome mutagenicity test . The mutagens in the organic matter were found to be extracted with serum but not with saline . The mutagenic activity of the serum extract of the tar, however, decreased to about 60% compared with that of the DMSO extract, when they were activated by S9 mix . On the other hand, without S9 mix, the mutagenic activities of the serum and DMSO extracts were about the same . Gel filtration of the serum extract was carried out and followed by mutagenicity testing of each fraction . It is suggested that the mutagens, which require metabolic activation, combine mainly with beta-lipoproteins and the direct mutagens with both alpha- and beta-lipoproteins in serum.

Mutat Res, 1983 Apr, 117(1-2), 21 - 9
Mutagenicity of dichloroacetylene and its degradation products trichloroacetyl chloride, trichloroacryloyl chloride and hexachlorobutadiene; Reichert D et al.; Dichloroacetylene (DCA) is a highly reactive compound that decomposes rapidly in contact with air into a series of chlorinated aliphatic hydrocarbons (e.g., phosgene, trichloroacetyl chloride, trichloroacryloyl chloride and hexachlorobutadiene) . Experiments were performed to compare the mutagenic properties of DCA and its degradation products on the histidine-dependent tester strains TA98 and TA100 of Salmonella typhimurium . In these experiments, DCA vapour was streamed under analytical control through the bacterial suspensions . DCA is soluble in aqueous solution and was stable under the experimental steady-state conditions of the bacterial exposure . There is a linear correlation between the supply of DCA vapour and solubilized DCA in the range of 1000 and 16 000 ppm . Mutagenic response was observed with strain TA100 if the bacteria were suspended in Oxoid medium . No mutagenicity could be detected with strain TA98 . DCA mixtures with acetylene, as used as stabilizer for animal experiments, were not mutagenic in either bacterial strain, irrespective of the presence or absence of S9 mix in the cell suspension . One of the degradation products of DCA, trichloroacryloyl chloride, showed pronounced mutagenic properties with and without drug-metabolizing enzymes . Other degradation products of DCA, such as trichloroacetyl chloride and hexachlorobutadiene, were not mutagenic, either in the presence or absence of liver homogenate.

Mutat Res, 1983 Apr, 117(1-2), 193 - 9
Mutagenicity of oxytetracycline; Blitek D et al.; Oxytetracycline hydrochloride, potassium nitrite and a combination of this antibiotic with the nitrite were tested for their mutagenicity in the host-mediated assay with mice as the host animals . The Salmonella typhimurium strain used was his G46 . The bacteria were injected intraperitoneally, and the test compounds were administered by a stomach tube . Neither oxytetracycline nor potassium nitrite were mutagenic for strain G46, but the combination of the compounds administered in the highest tolerated doses proved to be mutagenic for this Salmonella strain . The mutagenicity of the compounds was further evaluated by the micronucleus test in the bone marrow of Swiss mice . The test compounds were administered p.o., half the dose 30 h and the rest 6 h before the animals were killed . Oxytetracycline and the combination of oxytetracycline with potassium nitrite induced a significant increase in the frequency of micronuclei in polychromatic erythrocytes . Dose-response experiments with oxytetracycline and with the combination of the antibiotic with nitrite revealed an apparent no-effect level at 2 X 50 to 2 X 500 mg/kg . At higher doses both oxytetracycline and oxytetracycline with nitrite significantly influenced the ratio of erythrocytes to nucleated cells . The findings were compared with data obtained with dimethylnitrosamine included in both kinds of experiment.

Mutat Res, 1983 Apr, 117(1-2), 113 - 25
Modulation of aromatic amine mutagenicity in Salmonella typhimurium with rat-liver 9000 g supernatant or monolayers of rat hepatocytes as an activation system; Holme JA et al.; 2-Aminofluorene (AF), 2-acetylaminofluorene (AAF) and N-hydroxy-2-acetylaminofluorene (N-OH-AAF) were studied for mutagenic activity in S . typhimurium and either liver 9000 g supernatant fractions (S9) or monolayer cultures of hepatocytes isolated from Wistar rats were used as an activation system . All 3 compounds were converted into mutagens excreted into the incubation medium by the cell-culture system, with N-OH-AAF greater than AF greater than AAF . Cultures used 24 h after plating were less efficient in promutagen conversion than were cultures used after 2 h . Phenobarbital, but not 3-methylcholanthrene, pretreatment of the rats caused similar effects on AF, AAF and N-OH-AAF mutagenicity with both S9 and hepatocyte cultures . The mutagenicities of AF and AAF were reduced by the cytochrome-P-450 inhibitors metyrapone and alpha-naphthoflavone, whereas the mutagenicity of N-OH-AAF was increased by using both inhibitors . Further, the microsomal deacetylase inhibitor paraoxon caused only a moderate reduction in N-OH-AAF mutagenicity, but a total inhibition of AAF mutagenicity . No significant effect of paraoxon on AF mutagenicity was seen . With the S9 system, no effect of ascorbate on the mutagenicity of AF, AAF or N-OH-AAF was observed . In contrast, the mutagenicity of all 3 compounds was increased by ascorbate when hepatocyte cultures were used as activation system . Incubation of hepatocyte monolayers in a sulfate-free medium did not change the mutagenicity of AF, AAF or N-OH-AAF . Galactosamine, an inhibitor of glucuronidation in cells, increased the mutagenicity of AF, AAF and N-OH-AAF with hepatocyte cultures . The addition of cofactor for glucuronidation in the S9 system, however, had no effect . A reduction in mutagenicity of AF and AAF, but not that of N-OH-AAF, was observed with the addition of glutathione (GSH) in both the S9 and the hepatocyte systems . On the other hand, no effect of cellular GSH depletion was seen on aromatic-amine mutagenicity in the hepatocyte system . The data indicate that the hepatocyte culture system offers advantages over the conventional liver-sub-fraction activation system as a model, in vivo, for the metabolism of the aromatic amine mutagens/carcinogens.

Mutat Res, 1983 Apr, 117(1-2), 105 - 12
Conversion of Congo red and 2-azoxyfluorene to mutagens following in vitro reduction by whole-cell rat cecal bacteria; Reid TM et al.; Congo red, an azo dye derived from benzidine, and 2-azoxyfluorene, a derivative of 2-aminofluorene, were reduced during overnight incubation with a suspension of rat intestinal bacteria . High performance liquid chromatography and ultraviolet spectral analysis verified the presence of benzidine in extracts of the Congo red incubations and 2-aminofluorene in extracts of the 2-azoxyfluorene incubations . Extracts of the Congo red incubations were mutagenic toward Salmonella typhimurium TA1538 in the presence of a post-mitochondrial activating system, but Congo red was not mutagenic without this reductive pretreatment . Thus, the utility of the Ames test in screening for potential mutagens may be expanded by a reductive pretreatment utilizing cecal bacteria.

Mutat Res, 1983 Apr, 117(1-2), 1 - 8
Mutagenicity of bis- and mono-(2,3-dibromopropyl)phosphate, and their salts used as flame retardants, in the Salmonella/microsome system; Nakamura A et al.; The mutagenicity of pure synthesized samples of bis(2,3-dibromopropyl)phosphate (bis-BP) and mono(2,3-dibromopropyl)phosphate (mono-BP) against Salmonella typhimurium TA100 was examined in relation to microsomal activation of tris(2,3-dibromopropyl)phosphate (tris-BP) . Both mono- and bis-BPs were weak direct mutagens . Their mutagenicities increased with S9 mix, but the rates were much less than that of tris-BP . The magnesium and ammonium salts of mono- and bis-BPs were also prepared and their mutagenicities were examined with S9 mix in relation to 2 commercial flame retardants (our abbreviations: DB-1 and DB-2) . In both mono- and bis-BP series, an apparent increase of mutagenicity was observed in the order: ammonium salt greater than magnesium salt greater than free acid . On the other hand, mono-BP and its salts are usually more active than the corresponding bis-BPs independently of the kind of cation . DB-1 (DB-2), however, is more potent than the magnesium (ammonium) salts of mono- and bis-BPs, the constituents in DB-1 (DB-2) . No synergistic effect between mono-BP salts and bis-BP salts was observed . The different unknown mutagenic compounds in DB-1 and DB-2 are suggested.

J Bacteriol, 1983 Apr, 154(1), 84 - 91
flaAII (motC, cheV) of Salmonella typhimurium is a structural gene involved in energization and switching of the flagellar motor; Dean GE et al.; The flaAII gene of Salmonella typhimurium has also been termed motC and cheV, because defective alleles may give rise to a nonflagellate, paralyzed, or nonchemotactic phenotype . We isolated a temperature-sensitive motility mutant (MY1) and have found that the mutation occurs in the flaAII gene . In temperature-jump experiments, MY1 could be converted from highly motile to paralyzed within 0.5 s, demonstrating that flaAII is a structural gene whose product is immediately essential for motor rotation . The mutant, although chemotactic at permissive temperatures (less than 36 degrees C), had a higher clockwise rotational bias than did the wild type; it can therefore be regarded simultaneously as motC(Ts) and cheV (tumbly) . The only previously reported S . typhimurium cheV mutant was smooth-swimming . A shift toward counterclockwise bias accompanied loss of rotational speed in the restrictive temperature range . This result, by analogy with known proton motive force effects on motor switching, further indicates a central role of the flaAII (motC, cheV) protein in the energy transduction and switching process . Since there is no evidence associating it with the isolable entity known as the basal body, it may reside at the cytoplasmic face of the flagellar motor.

Infect Immun, 1983 Apr, 40(1), 236 - 44
Effect of lipopolysaccharide mutations on the pathogenesis of experimental Salmonella gastroenteritis; Mintz CS et al.; Lipopolysaccharide mutants of Salmonella typhimurium provoked diminished amounts of fluid in rabbit ileal loops as compared with the response to the wild type . The responses elicited by these mutants ranged from 0 to 60% of that caused by the parent strain . Two completely rough mutants and one leaky rough mutant were chosen for further study . Purified lipopolysaccharide from the parent and the mutant strains failed to stimulate fluid exsorption in ileal loop experiments . Histological studies revealed that the three lipopolysaccharide mutants were less invasive than wild type and were less able to generate an inflammatory reaction in the rabbit ileum . A Salmonella enterotoxin was present in culture filtrates from one rough mutant and the wild type; however, the rough mutant appeared to produce less toxin . Enterotoxic activity was absent in culture filtrates from the two other rough mutants . These results suggest that reductions in both invasiveness and the ability to produce Salmonella enterotoxin decreased the ability of these mutants to provoke fluid exsorption . Also, the results indicate that lipopolysaccharide mutations can have a profound effect on the enteropathogenic properties of S . typhimurium.

Food Chem Toxicol, 1983 Apr, 21(2), 221 - 3
Mutagenicity study of nine monoalkyl phthalates and a dialkyl phthalate using Salmonella typhimurium and Escherichia coli; Yoshikawa K et al.; Nine monoalkyl (C1-C8) phthalates and di-(2-ethylhexyl) phthalate (DEHP) were assayed for mutagenicity in two strains of Salmonella typhimurium (TA98 and TA100) and two strains of Escherichia coli WP2 try- (uvrA+ and uvrA-) with and without metabolic activation with S-9 mix . The procedure of Ames et al . (Mutation Res . 1975, 31, 347) was used, with minor modifications . None of the compounds tested showed any mutagenic activity, but all the monoalkyl phthalates showed some lethality towards the S . typhimurium strains, the most toxic being monoheptyl phthalate . A marginally lethal effect on the Salmonella strains was shown by DEHP, but only at the highest concentration tested (2000 micrograms/plate) and in the absence of S-9 mix.

Food Chem Toxicol, 1983 Apr, 21(2), 175 - 80
Negative Ames tests of epoxide fatty methyl esters derived from hemolysis of linoleic acid hydroperoxides; Gardner HW et al.; Five isomeric epoxyhydroxyene and epoxyoxoene fatty esters derived from hemolytic decomposition of linoleic acid hydroperoxide were tested for mutagenicity by the "Ames' top-agar incorporation method using S-9 mix derived from livers of male rats pretreated with Aroclor 1254 . The epoxide fatty esters tested--methyl trans-12,13-epoxy-erythro-11-hydroxy-cis(trans)-9-octadecenoate and methyl trans-12,13-epoxy-threo-11-hydroxy-cis(trans)-9-octadecenoate (each composed of approximately 80% cis-9-ene and 20% trans-9-ene), methyl trans-12,13-epoxy-9-oxo-(trans-10-octadecenoate, methyl trans-12,13-epoxy-9-hydroxy-trans-10-octadecenoate and methyl cis-12,13-epoxy-9-oxo-trans-10-octadecenoate--had structural characteristics similar to certain potent mutagens . However, these esters were not mutagenic in Salmonella typhimurium strains TA100, TA98 or TA1537 at concentrations up to 2000 micrograms/test plate . Under the same test conditions, the methyl ester of hydroperoxy linoleic acid, from which these epoxides were derived, was weakly mutagenic in strain TA100 and possibly also in strain TA98.

Environ Res, 1983 Apr, 30(2), 427 - 41
The mutagenicity of a Prudhoe Bay crude oil and its residues from an experimental in situ burn; Sheppard EP et al.; Fresh and weathered Prudhoe Bay crude oil as well as residues from its combustion were tested for mutagenicity using strain TA98 in the Ames Salmonella typhimurium/liver microsome test . Because of the toxicity of the oils involved, mutagenic effects were clearly visible only at very low concentrations . All samples were found to be mutagenic, with precipitated plume having the greatest activity followed by the burn residue, the weathered oil, and fresh crude, respectively . The most polar components of the neutral fraction of the samples displayed the greatest mutagenicity.

Naturwissenschaften, 1983 Apr, 70(4), 173 - 9
{Microbiological short-time tests for the evaluation of mutagenic potential of chemical substances}; Gericke D; During the last 20 years it became much more interesting to test new chemicals as fast as possible for their carcinogenic potency . Therefore new test models were developed . Mutagenicity seems to be one sign for carcinogenicity . Therefore test systems using microorganisms were studied which are influenced by mutagenic substances . These systems are described, first of all the Ames-Test, using revertants of Salmonella typhimurium, secondly the Escherichia coli system deficient of DNA-polymerase A (DNA-Pol A-) . The yeast Saccharomyces cerevisiae was introduced some years ago and finally the Neurospora crassa system serves as an additional test to define exactly the localisation of mutations . The tests and their problems are discussed.

J Natl Cancer Inst, 1983 Apr, 70(4), 767 - 9
Increased mutagenicity of chloroethylnitrosoureas in the presence of a rat liver S9 microsome mixture; Suling WJ et al.; The mechanism for an enhanced effect of Aroclor 1254-induced Sprague-Dawley rat liver 9,000 x g supernatant (S9) microsome preparation on the mutagenicity of 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU), 1-(2-chloroethyl)-3-cyclohexyl-N-nitrosourea (CCNU), and 2-{3-(2-chloroethyl)-3-nitrosoureido}-2-deoxy-D-glucopyranose (chlorozotocin) for Salmonella typhimurium strain TA1535 was studied . Although all three compounds were direct-acting mutagens, rat liver S9 increased the mutagenic response to BCNU, CCNU, and chlorozotocin . The enhanced mutagenic effect was independent of NADPH . Heat-denatured S9 enhanced the mutagenicity of BCNU and CCNU, but not that of chlorozotocin . Mutagenic enhancement, however, was less than that observed with untreated S9 . The substitution of extractable S9 lipid and bovine serum albumin for S9 in the reaction mixture resulted in an enhanced mutagenicity of CCNU with little or no effect on BCNU or chlorozotocin mutagenicity . These results suggest that the enhanced mutagenicity of CCNU, and possibly that of BCNU, in the presence of S9 was due in part to nonspecific factors that are present in the S9 preparation.

Mutat Res, 1983 Apr, 117(1-2), 31 - 40
Microbial mutagenicity of 3- and 4-ring polycyclic aromatic sulfur heterocycles; Pelroy RA et al.; The stable isomers of 3- and 4-ring polycyclic aromatic sulfur heterocycles were tested for mutagenicity in the Ames standard plate incorporation test and a liquid pre-incubation modification of the Ames test . Of the 4 three-ring compounds tested, only naphtho{1,2-b}thiophene was mutagenic . Of the four-ring compounds, 7 of 13 were mutagenic in the standard Ames or pre-incubation Ames test . The highest activity for the 4-ring compounds was observed for phenanthrol{3,4-b}thiophene, a compound of approximately the same mutagenic potency in the Ames test as benzo{a}pyrene . The other active 4-ring compounds were of considerable less mutagenic potency than phenanthrol{3,4-b}thiophene . Mutagenicity for two of the 4-ring aromatic thiophenes could only be detected in the liquid pre-incubation Ames test . Salmonella typhimurium TA100 was the most sensitive strain to mutagenesis by these compounds, followed by TA98 . All mutagenesis was indirect, requiring metabolic activation.

J Biol Chem, 1983 Mar 25, 258(6), 3769 - 74
Salmonella typhimurium mutants defective in UDP-D-galactose:lipopolysaccharide alpha 1,6-D-galactosyltransferase . Structural, immunochemical, and enzymologic studies of rfaB mutants; Wollin R et al.; The biochemical defect in a class of Salmonella typhimurium mutants (rfaB) defective in biosynthesis of the lipopolysaccharide core is described . Structural, immunochemical and enzymologic studies showed that: (i) the core polysaccharide completely lacked the branch alpha 1,6-D-galactosyl residue of the normal lipopolysaccharide as shown by methylation analysis and 1H nmr spectroscopy; (ii) the mutant lipopolysaccharides acted as acceptors for transfer of D-galactose from UDP-D-galactose into alpha 1,6 linkage to the proximal D-glucosyl residue of the core in a reaction catalyzed by an enzyme activity present in extracts from rfaB+ cells; (iii) the UDP-D-galactose:(glucosyl)lipopolysaccharide alpha 1,6-D-galactosyltransferase activity was absent from extracts of rfaB cells.

Science, 1983 Mar 25, 219(4591), 1427 - 9
Activation of 2-aminofluorene by cultured plant cells; Plewa MJ et al.; Cultured tobacco plant cells activated 2-aminofluorene to an agent mutagenic to Salmonella typhimurium strain TA98 . The plant activation of 2-aminofluorene is heat-inactivated and may not involve solely cytochrome P-450 . The kinetics of activation demonstrated both time- and concentration-dependent responses.

Biochim Biophys Acta, 1983 Mar 15, 756(1), 41 - 8
Different biosynthetic pathways of the pyrimidine moiety of thiamin in procaryotes and eucaryotes; Yamada K et al.; {14C}Formate is incorporated into the C-2 of the pyrimidine moiety of thiamin by Escherichia coli and Salmonella typhimurium . In Saccharomyces cerevisiae, it is incorporated into C-4 . Radioactive carbons of {1-14C}glycine and {2-14C}glycine are incorporated by S . typhimurium into the C-4 and C-6 of the pyrimidine, respectively, but not by S . cerevisiae . These facts suggest that procaryotes and eucaryotes have different biosynthetic pathways for pyrimidine . In this study, the procaryotes tested incorporated {14C}formate into the C-2 and the eucaryotes incorporated it into the C-4 of the pyrimidine.

J Biol Chem, 1983 Mar 10, 258(5), 3266 - 79
Genetic characterization of the folding domains of the catalytic chains in aspartate transcarbamoylase; Jenness DD et al.; In Salmonella typhimurium strains which produce high constitutive levels of aspartate transcarbamoylase due to the pyrH700 mutation, the bulk of the carbamoyl phosphate of the cell is consumed for the biosynthesis of pyrimidines . As a consequence, there is little substrate available for arginine synthesis and the cell growth is impeded . Suppression of arginine auxotrophy by mutations which block aspartate transcarbamoylase activity provides a positive selection technique for mutant strains defective in this enzyme activity . A genetic analysis was performed on 29 mutant strains harboring defects in the structural gene pyrB, encoding the catalytic chains of aspartate transcarbamoylase of Escherichia coli . Extracts from 15 strains contained intact, inactive enzyme-like molecules of the same size as the purified wild type enzyme . These same extracts contained a predominant polypeptide chain which migrated electrophoretically at the same rate as catalytic chains from wild type enzyme . In addition to these 15 different missense mutants, 14 others (presumably chain-terminating mutants) were isolated; no polypeptides corresponding to full length catalytic chains were detected in these strains . Based on their reversion and suppression properties, seven were designated as frameshift and two as amber nonsense . A fine structure recombination map of the pyrB locus was constructed from a series of three-factor transductional crosses . Mutational sites were correlated with regions in the polypeptide sequence by relating their map positions to that of mutation pyrB231 which results in an amino acid replacement at position 128 . Moreover, since recent crystallographic studies indicate that residue 128 is located near the junction between the NH2- and COOH-terminal folding domains, the mutational sites can be placed within either of these two regions of tertiary structure . Interallelic complementation experiments showed four units of complementation . Those defining the alpha and beta units were missense mutants with their mutational sites in the NH2- and COOH-terminal domains, respectively . The mutants determining the delta and gamma units involved premature polypeptide chain termination and their mutational sites were correlated with distal regions of the two respective domains . Several mutants of the chain-terminating type failed to complement members of more than one unit . Possible effects of the various mutations and their implications for mechanisms of complementation and enzyme activity are presented.

J Biol Chem, 1983 Mar 10, 258(5), 2870 - 4
Purification and characterization of recA protein from salmonella typhimurium; Pierre A et al.; recA protein was purified to homogeneity from Salmonella typhimurium TA98 strain after induction of the cells by nalidixic acid . The purification was monitored with a radioimmune assay and involved a specific elution of the protein by ATP from a single-stranded DNA-cellulose column . From 240 liters of cell culture we obtained 40 mg of recA protein which was more than 98% pure . This protein exhibited the same molecular weight as measured on sodium dodecyl sulfate-polyacrylamide gel and the same isoelectric point as the Escherichia coli recA protein purified by a similar procedure . In addition, the S . typhimurium recA protein is endowed with a single-stranded DNA-dependent ATPase activity and cleaves the phage lambda repressor in vitro at the same rate as E . coli recA protein and with the same qualitative requirements . However, peptide mapping with the Staphylococcus aureus V8 protease and cross-reaction with heterologous antibodies show that these two proteins are slightly different.

Mutat Res, 1983 Mar, 116(3-4), 361 - 7
Induction of chromosome damage by methylene chloride in CHO cells; Thilagar AK et al.; The genotoxicity of methylene chloride was determined using sister-chromatid exchange (SCE) and chromosome aberration assays in cultured Chinese hamster ovary (CHO) cells . Methylene chloride caused extensive chromosome aberrations both with and without metabolic activation . However, the results of the SCE assay were negative for methylene chloride . These results agree with previously observed genotoxic effects of methylene chloride in Salmonella typhimurium and Saccharomyces cerevisiae . The fact that methylene chloride causes chromosome aberrations without increasing the SCE level indicates that complete reliance on the induction of SCE as a test system for assessing chromosomal effects is not valid.

Environ Health Perspect, 1983 Mar, 49, 21 - 5
N-hydroxylation of carcinogenic and mutagenic aromatic amines; Kato R et al.; N-Hydroxylation and mutagenic activation of heterocyclic aromatic amines from protein pyrolysis products were studied in rat liver microsomes and nuclei, rat hepatocytes and various species of purified cytochrome P-450 . These mutagenic amines include Trp-P-2 (3-amino-1-methyl-5H-pyrido{4,3-b}indole), Trp-P-1 (3-amino-1,4-dimethyl-5H-pyrido{4,3-b}indole), Glu-P-1 (2-amino-6-methyldipyrido-{1,2-a:3',2'-d}imidazole), Glu-P-2 (2-amino-dipyrido{1,2-a:3',2'-d}imidazole) and IQ (2-amino-3-methyl-3H-imidazo-{4,5-f}quinoline) . The number of revertants of Salmonella typhimurium TA 98 was always correlated to the amount of each of the N-hydroxylated metabolites in various experimental conditions . The N-hydroxylated amines covalently bound to DNA directly or after being acylated with amino acids by amino-acyl-tRNA synthetase . Various species of cytochrome P-450 preparations showed markedly different activity in N-hydroxylation and mutagenic activation of Trp-P-2, Glu-P-1 and IQ . A high spin form of cytochrome P-450, isolated from the liver of PCB-treated rats, showed very high activity in N-hydroxylation of Trp-P-2, Glu-P-1 and 2-aminofluorene, although its activity was very low in benzo(a)pyrene hydroxylation . The present results indicate that different species of cytochrome P-450 are involved in the N-hydroxylation and mutagenic activation of aromatic amines.

J Med Chem, 1983 Mar, 26(3), 309 - 12
Mutagenicity and chemistry of N-nitroso-N-(p-substituted-benzyl)methylamines; Singer GM et al.; The relative mutagenicities of N-nitroso-N-(p-substituted-benzyl)methylamines in Salmonella typhimurium TA 1535 were tested in order to determine whether biological activity is affected by the electron density at a nitrosamine alpha carbon . The order of potency was as follows: X = Cl greater than CN greater than Br greater than NO2 greater than H greater than CH3O greater than CH3 greater than F much greater than COOH . No direct correlation was apparent, nor was there any obvious correlation between biological activity and the extent of base-catalyzed hydrogen-deuterium exchange at the alpha carbons.

Trop Geogr Med, 1983 Mar, 35(1), 37 - 41
Drug resistance among Salmonellae in Kuwait; Chugh TD et al.; The status of drug resistance among Salmonella spp . prevalent in Kuwait during 1979-1980 has been assessed . Antibiotic sensitivity of 345 clinical isolates against 14 antimicrobial agents was done by disc-diffusion technique and their MIC was determined by plate dilution . Only 9.6% of these isolates were sensitive to all the 14 drugs . There was resistance to sulfisoxazole (78%), tetracycline (69%), kanamycin (61%), ampicillin (56%), streptomycin (53%), chloramphenicol (38%) and mezlocillin (38%) . Multiple drug resistance (three or more drugs) was seen in 71% of isolates and many of them were resistant to five or more drugs . The common resistance patterns observed were ACGKSSuT, ACKSSuT, ACSSuT, and ASSuT . Co-trimoxazole was the drug of choice as only 15 strains (4%) were resistant to it . The minimum inhibitory concentration (MIC) of the resistant strains was invariably high . Salmonella typhimurium was the commonest (41%) single species and the frequency and level of resistance was higher in this serotype than in others.

Bull Eur Physiopathol Respir, 1983 Mar-Apr, 19(2), 143 - 5
Resistance to infection: looking for new genes; Glynn AA; Genetic factors in resistance to infection, somewhat neglected with the development of microbiology, are again receiving careful attention . Although there are numerous reports of infection resulting from deficiencies in, for example, immunoglobulins or complement components, specific abnormalities in resistance associated with particular HLA groups have been unexpectedly rare . In mice, the Ity gene on chromosome 1, which is important in resistance to Salmonella typhimurium infection, may well be identical with the Lsh and Bcg genes concerned with resistance to Leishmania donovani and Mycobacterium bovis BCG . The most likely common factor determining resistance to three such disparate organisms is the macrophage, but direct evidence of its role is lacking . The high and low antibody-producing strains of mice selected by BIOZZI {2} are respectively sensitive and resistant to many intracellular infections including S . thyphimurium . Experiments with hybrids between Biozzi mice and other inbred strains suggest that the high line carries the Itys (salmonella susceptibility gene) plus another gene increasing susceptibility . Low line mice carry the Ityr gene plus another gene increasing resistance . Inbred mice are invaluable for analogizing gene interactions which, once understood, can be looked for in man.

Mutat Res, 1983 Mar, 119(3), 289 - 91
Evaluation of mutagenic effect of the fungicide fenaminosulf in Drosophila melanogaster; Pai SB; Fenaminosulf (p-dimethylaminobenzenediazo sodium sulfonate, CAS registry No . 140-56-7) which is an active ingredient in several commercial fungicides was reported to be mutagenic in Salmonella typhimurium (McCann et al., 1975), Bacillus subtilis (Kada et al., 1974) and shown to cause chromosome aberrations in plants (Zutshi and Kaul, 1975) . Since fenaminosulf has structural similarity to the potent carcinogen, butter yellow (p-dimethylaminoazobenzene, CAS registry No . 60-11-7), the present studies were undertaken to evaluate the mutagenic potential of this fungicide in Drosophila melanogaster . Fenaminosulf administered at 10 mg/100 ml food medium failed to induce sex-linked recessive mutations in Drosophila . Since Drosophila has drug-metabolizing enzymes similar to those of mammals (Vogel, 1975), it is suggested that the lack of mutagenic activity of fenaminosulf could be due to the conversion of fenaminosulf to non-mutagenic derivatives in Drosophila.

Zentralbl Bakteriol Mikrobiol Hyg {A}, 1983 Mar, 254(1), 69 - 77
{Plasmid patterns of Salmonella typhimurium lysotype n.c . 1/72/n.c . strains from East Germany}; Tietze E et al.; Salmonella typhimurium strains isolated in the German Democratic Republic between 1972 and 1980 mainly belong to phage type n.c.1/72/n.c . and biochemotype b . Nearly all of these strains are characterized by an identical basic plasmid pattern . Thus, they may be considered to be independent isolates of the same epidemic strain . Moreover, some multiple drug resistant offsprings of that epidemic strain have been characterized by their carriage of an additional IncH-1 R plasmid . However, a few strains of phage type n.c.1/72/n.c . were found to differ fundamentally in their plasmid patterns from that of the epidemic strain . The phage pattern of these strains is determined by a conjugative R plasmid belonging to the incompatibility group IncI4 . Despite of the same phage- and biochemotype these strains must be considered non-related with the epidemic strain, therefore . The analysing of the plasmid pattern of bacterial strains turns out to be an important contribution to the investigation of epidemic processes.

Toxicology, 1983 Mar-Apr, 26(3-4), 207 - 12
Lack of mutagenic activity of dimethylformamide; Antoine JL et al.; Different test systems have been utilized to evaluate the mutagenic and carcinogenic properties of dimethylformamide (DMF), an aliphatic amide used as a solvent in chemical industry . The Ames test was performed on different strains of Salmonella typhimurium, whereas the ability of DMF to induce structural aberrations in eukaryotic chromosomes was tested by in vitro observations on human lymphocytes and in vivo experiments on mouse bone marrow . Furthermore, male mice were treated with DMF for the induction of sperm abnormalities . The negative results obtained in all test systems as well as the absence of positive reports in man or in experimental animals with respect to induction of cancers suggest strongly that DMF is devoid of mutagenic or carcinogenic properties.

Zh Mikrobiol Epidemiol Immunobiol, 1983 Mar, (3), 26 - 32
{Biological characteristics of Salmonella typhimurium obtained from different sources 1975-1980}; Kamenskaia IN et al.; Distinct differences in a number of biological properties between S . typhimurium hospital strains and cultures of animal origin have been revealed . During 1975-1980 changes in the fermentation of lysine were observed in hospital strains and the retarded fermentation of sorbitol was revealed in strains of animal origin . S . typhimurium 1R, a new highly virulent biovariant resistant to antibiotics, and enzymatic varieties of biovar 11S were isolated . The nonstability of enzymatic differences between hospital strains and cultures of animal origin necessitates their constant observation in order to differentiate these cultures for the purpose of epidemic analysis . Complete correlation between the properties of cultures circulating on a limited territory and the character of morbidity in Salmonella infection demonstrates the epidemiological importance of the intraspecific differentiation tests under study.

Infect Immun, 1983 Mar, 39(3), 1481 - 4
Polyclonal activation of B-lymphocytes in vivo by Salmonella typhimurium lipoprotein; Johnson RB et al.; Lipoprotein prepared from the outer membrane of Salmonella typhimurium is a polyclonal activator of murine B-lymphocytes . It was shown to be mitogenic for splenic cultures, stimulating increased incorporation of {3H}thymidine into DNA . When injected intravenously into mice, the lipoprotein induced splenomegaly and polyclonal B-cell activation . The latter was evident from an increase in the number of plaque-forming cells against trinitrophenylated sheep erythrocytes . Similar results were obtained with Escherichia coli lipoprotein.

Infect Immun, 1983 Mar, 39(3), 1187 - 95
Effect of growth phase and cell envelope structure on susceptibility of Salmonella typhimurium to the lactoperoxidase-thiocyanate-hydrogen peroxide system; Purdy MA et al.; The lactoperoxidase-thiocyanate-hydrogen peroxide system was found to have both bacteriostatic and bactericidal activities against strains of Salmonella typhimurium . The bactericidal activity was clearly dependent on the permeability of the bacterial cell envelope . The deep rough mutant TA1535, with the most permeable cell envelope, was killed both at neutral and acid pH, whereas very little or no killing was observed with the intact cells of the parent strain hisG46 . The delta gal mutant, TA1530, representing an intermediate in cell envelope permeability, was inhibited to a much lesser extent than TA1535 . Bacteria in log phase of growth were more sensitive to the bactericidal effects than were those in stationary phase . Growth phase had little influence on the bacteriostatic effects . The hisG46 strain produced significant quantities of acid in the presence of glucose . This acid production was inhibited by the lactoperoxidase-thiocyanate-hydrogen peroxide system, and, in contrast to results obtained with several strains of streptococci, this inhibition was not reversed by addition of a reducing agent (2-mercaptoethanol).

Mutat Res, 1983 Mar, 116(3-4), 399 - 405
Absence of mutagenic activity of WHR-1142A, lidamidine hydrochloride, in 4 short-term tests for mutagenic/carcinogenic potential; Allen JA et al.; WHR-1142A, lidamidine hydrochloride, an antidiarrhoeal agent, was tested for possible mutagenic/carcinogenic activity in the Ames Salmonella typhimurium/metabolic activation test, the micronucleus test, by analysis of metaphase chromosomes obtained from human lymphocytes grown in culture and in a cell transformation assay . No evidence of mutagenic/carcinogenic activity due to WHR-1142A, lidamidine hydrochloride, was found in any of the 4 tests.

Mutat Res, 1983 Mar, 116(3-4), 305 - 15
Mutagenicity of selected sulfonated azo dyes in the Salmonella/microsome assay: use of aerobic and anaerobic activation procedures; Brown JP et al.; A selection of 16 sulfonated azo dyes of both the monoazo type and diazo dyes based on benzidine, o-tolidine and o-dianisidine were assayed for mutagenicity in Salmonella typhimurium strains TA98 and TA100 employing both aerobic and anaerobic preincubation procedures . 3 food dyes, FD & C Red No . 40 and Yellows No . 5 and No . 6 were non-mutagenic in all tests . 5 dyes were mutagenic with aerobic treatment (trypan blue, Pontacyl Sky Blue 4BX, Congo Red, Eriochrome Blue Black B, dimethylaminoazobenzene) and 6 were mutagenic aerobically with riboflavin and cofactors (Deltapurpurin, trypan blue, Pontacyl Sky Blue 4BX, Congo Red, methyl orange, Ponceau 3R) . Anaerobic preincubation involving enzymatic reduction of the dyes led to a different pattern of mutagenicity, with trypan blue giving much enhanced mutagenicity; Eriochrome Blue Black B, Pontacyl Sky Blue 4BX, Deltapurpurin and Congo Red exhibiting similar activity to aerobic preincubation; and methyl orange and Ponceau 3R yielding no mutagenicity . The results are interpreted with respect to an hypothesis involving partial reduction of the azo bond under differing degrees of aerobiosis via azo-anion radicals and hydrazo intermediates.

Mutat Res, 1983 Mar, 116(3-4), 297 - 304
Mutagenicity of anthraquinones in the Salmonella preincubation test; Tikkanen L et al.; The mutagenicities of 15 naturally occurring anthraquinones were examined in Salmonella typhimurium strains TA98, TA100 and TA2637 by the preincubation method . 7 of the 15 compounds tested, i.e., chrysazin, emodin, islandicin, alizarin, chrysophanol, 2-hydroxyanthraquinone and emodic acid, were strong mutagens in strain TA2637 with metabolic activation . All of these compounds contain 1-3 hydroxyl groups, and some also have methyl groups . Cynodontin, an anthraquinone with 4 hydroxyl groups and 1 methyl group, was only slightly mutagenic in strain TA2637 . 2-Hydroxyanthraquinone, alizarin, emodin, islandicin and chrysazin were also mutagenic in strain TA100 with S9 mix . All the bisanthraquinones tested, i.e., skyrin, (+)rugulosin, (-)luteoskyrin, (-)rubroskyrin and sennoside A, were non-mutagenic in this test system with or without metabolic activation . Unsubstituted anthraquinone and anthrone were also non-mutagenic . These results show that hydroxyl substituents are necessary for the mutagenicity of anthraquinones, the optimal substitutions being 1-3 hydroxyl groups per molecule . The 4th hydroxyl group, in the compound cynodontin reduces the mutagenicity considerably.

Mutat Res, 1983 Mar, 116(3-4), 217 - 38
Structural specificity of aromatic compounds with special reference to mutagenic activity in Salmonella typhimurium--a series of chloro- or fluoro-nitrobenzene derivatives; Shimizu M et al.; The mutagenicity of 21 chloro- or fluoronitrobenzene compounds and 9 chloro- or fluorobenzene compounds in Salmonella typhimurium (strains TA98, TA1538, TA1537, TA100 and TA1535) was examined . The tests were carried out under the conditions of absence and presence of liver microsomal activation . 15 nitro-group compounds had mutagenic activity; above all, compounds of fluoronitrobenzene were mutagenic for both types of strain . On the other hand, chloronitrobenzene compounds were mutagenic for base-pair substitution strains only . Mutagenic activity was exhibited by all compounds having a chloro or fluoro substituent at the para and ortho position in the nitrobenzene nucleus . All compounds without a nitro substituent showed no mutagenic activity.

Mutat Res, 1983 Mar, 116(3-4), 185 - 216
Further mutagenicity studies on pesticides in bacterial reversion assay systems; Moriya M et al.; A total of 228 pesticides (88 insecticides, 60 fungicides, 62 herbicides, 12 plant-growth regulators, 3 metabolites and 3 other compounds) was tested for mutagenicity in bacterial reversion-assay systems with 5 strains (TA100, TA98, TA1535, TA1537 and TA1538) of Salmonella typhimurium and a strain (WP2 hcr) of Escherichia coli . 50 pesticides (25 insecticides, 20 fungicides, 3 herbicides, 1 plant-growth regulator and 1 other compound) were found to be mutagenic . 5 of them required metabolic activation (S9 mix) for their activities . Among various chemical groups, organic phosphates, halogenated alkanes and dithiocarbamates showed higher ratios of mutagens . Although 22 of the pesticides tested have been reported to be carcinogenic, 7 of them, i.e., captain, DBCP, EDB, EDC, ETU, HEH and nitrofen, were detected as mutagens in the present assay . Most of the other 15 non-mutagenic carcinogens were organochlorine pesticides such as alpha-BHC, chlorobenzilate, p,p'-DDT, dieldrin and quintozene.

Mutat Res, 1983 Mar, 108(1-3), 45 - 56
Rate of induced forward mutation at 3 genetic loci in Salmonella typhimurium; Skopek TR et al.; The rate of forward mutation to 8-azaguanine, 5-fluorouracil and azetidine carboxylic acid resistance was measured in Salmonella typhimurium following treatment with 18 chemical mutagens . Although the absolute frequency of both spontaneous and chemically-induced mutation was different at the markers scored, the 3 selection systems were found to be equisensitive: each system produced a statistically significant response at approximately the same mutagen concentration . This result suggests that in Salmonella the target size present in a given forward mutation assay is sufficiently large to approximate the level of mutation occurring elsewhere in the chromosome in sections of DNA of similar size.

Proc Natl Acad Sci U S A, 1983 Mar, 80(5), 1159 - 63
An intermediate step in translocation of lipopolysaccharide to the outer membrane of Salmonella typhimurium; Mulford CA et al.; Evidence for transient localization of newly synthesized lipopolysaccharide at the periplasmic face of the inner membrane has been obtained by immunoelectron microscopic techniques . Salmonella typhimurium galE mutants in which O-antigen synthesis is dependent on addition of exogenous galactose were employed, and the distribution and fate of pulse-synthesized O antigen was examined by indirect ferritin labeling with anti-O-antigen IgG of spheroplasts prepared by treatment with lysozyme/EDTA . O-reactive lipopolysaccharide appeared rapidly at the exposed periplasmic face of the inner membrane after addition of galactose and was rapidly depleted upon termination of the pulse . Control experiments showed that secondary redistribution of lipopolysaccharide from outer membrane did not occur under the conditions employed for spheroplast formation and immunolabeling, and the pulse-chase kinetics were consistent with those expected for an intermediate in translocation of lipopolysaccharide to the outer membrane . In addition, undecaprenol-linked O antigen was detectable at the periplasmic face of the inner membrane within 30 sec after addition of galactose to a galE deep rough double mutant, and it accumulated stably in that location . The mutation in synthesis of the lipopolysaccharide core in the deep rough strain prevents transfer of O-antigen chains from undecaprenol phosphate to lipopolysaccharide . The result suggests that attachment of O antigen to lipopolysaccharide occurs on the extracytoplasmic side of the inner membrane and supports the conclusion that lipopolysaccharide is translocated to the outer membrane from the periplasmic, rather than the cytoplasmic, face of the inner membrane.

Mutat Res, 1983 Mar, 119(3), 281 - 5
In vitro production of azide mutagenic metabolite in Arabidopsis, Drosophila and Neurospora; Rosichan JL et al.; The ability of Arabidopsis, Drosophila and Neurospora to convert azide to its mutagenic metabolite was investigated . Cultures of these organisms all contained significant levels of O-acetylserine sulfhydrylase activity . Extracts from each organism produced a product from O-acetylserine and azide in vitro which was mutagenic in Salmonella typhimurium TA1530.

J Bacteriol, 1983 Mar, 153(3), 1259 - 65
Oligopeptidase-deficient mutants of Salmonella typhimurium; Vimr ER et al.; An oligopeptidase that hydrolyzes N-acetyl-L-alanyl-L-alanyl-L-alanyl-L-alanine (AcAla4) has been identified in extracts of Salmonella typhimurium . Mutants lacking this activity have been isolated in dcp mutant strains by screening extracts of mutagenized clones for failure to hydrolyze AcAla4 or by screening colonies for inability to use AcAla4 as a nitrogen source . Double mutants (dcp optA) lacking both oligopeptidase A and dipeptidyl carboxypeptidase cannot use AcAla4 as a nitrogen source, although dcp+ optA and dcp optA+ strains grow on this peptide . The mutations responsible for the loss of activity map at a locus (optA) between asd (75 map units) and xylA (78 map units) . Oligopeptidase A hydrolyzes certain N-blocked tetrapeptides, unblocked pentapeptides, and unblocked hexapeptides, usually but not always liberating the C-terminal tripeptide . These two activities seem to be responsible for the production of a large fraction of the dipeptides that accumulate during protein breakdown in a pepN pepA pepB pepD strain.

J Bacteriol, 1983 Mar, 153(3), 1252 - 8
Dipeptidyl carboxypeptidase-deficient mutants of Salmonella typhimurium; Vimr ER et al.; Mutants of Salmonella typhimurium deficient in dipeptidyl carboxypeptidase have been isolated by screening for clones unable to use N-acetyl-L-alanyl-L-alanyl-L-alanine (AcAla3) as the sole nitrogen source . An insertion of the transposable element Tn10 near dcp (the locus coding for dipeptidyl carboxypeptidase) has been isolated and used to map the locus in the interval between purB and trp, an otherwise genetically silent region of the S . typhimurium map . All dcp mutants could still grow using N-acetyl-L-alanyl-L-alanyl-L-alanyl-L-alanine (AcAla4) as the sole nitrogen source . Crude extracts from the dcp mutants failed to hydrolyze AcAla3 but retained approximately 80% of the wild-type activity toward AcAla4 . Several lines of evidence indicate that hydrolysis of AcAla4 in the dcp mutant results from the action of a new peptidase distinct from dipeptidyl carboxypeptidase . A mutant strain lacking dipeptidyl carboxypeptidase in addition to peptidases N, A, B, and D showed reduced protein breakdown during carbon starvation compared with a strain lacking only peptidases N, A, B, and D.

Res Vet Sci, 1983 Mar, 34(2), 188 - 92
Effect of reticuloendotheliosis virus on the response of chickens to Salmonella typhimurium infection; Motha MX et al.; Groups of 25 chickens free of maternal antibody to reticuloendotheliosis virus (REV) were inoculated with either third or seventh passage REV at either one or seven days of age . Some of the birds inoculated at day 1 with REV were inoculated with Salmonella typhimurium either concurrently or six or 13 days later while some of those inoculated with REV at day 7 were inoculated concurrently with S typhimurium . At day old, infection with S typhimurium alone caused the death of 12 of 25 chicks whereas in the dual infection, using the third passage REV, 18 of 25 birds died . Similarly no seven or 14 day old chickens died when challenged with S typhimurium alone, but previous day-old infection with REV caused a respective mortality of eight of 25 and five of 25 birds . With the seventh passage REV a similar pattern was seen . At day old S typhimurium infection alone killed seven of 25 birds whereas combined with virus the mortality was 14 of 25 and while S typhimurium alone killed none of 25 chicks infected at seven days old, the mortality in birds also infected with REV was 14 of 25 . Combined virus and bacterial infections did not increase the proportion of feathering defects in birds surviving S typhimurium infections . There was a significantly higher proportion of feathering defects in birds infected with third passage virus compared with seventh passage virus . Although a higher proportion of birds had antibody responses to REV in the seventh than in the third passage group, there was no discernible difference in the effect the different viruses had on chickens' susceptibility to S typhimurium.

Proc Natl Acad Sci U S A, 1983 Mar, 80(5), 1207 - 11
Synthesis of aspartate transcarbamoylase in Escherichia coli: transcriptional regulation of the pyrB-pyrI operon; Navre M et al.; The first committed reaction in pyrimidine biosynthesis in Escherichia coli and Salmonella typhimurium is catalyzed by the allosteric enzyme aspartate transcarbamoylase (aspartate carbamoyltransferase; carbamoylphosphate:L-aspartate carbamoyltransferase, EC 2.1.3.2), the product of the pyrB-pyrI operon . Regulation of the pyrimidine pathway is achieved in part by changes in the enzyme's catalytic activity as a function of the concentration of substrates and other metabolites as well as by variations in enzyme synthesis in response to changes in cellular levels of pyrimidine nucleotides . Although there is substantial evidence that UTP concentration has a marked influence on expression of the pyrB-pyrI operon, the mechanism of this control is not known . We have cloned the operon and determined the nucleotide sequence of the region preceding the first structural gene (pyrB) . These studies show two regions sharing considerable homology with the consensus sequence of E . coli promoters, a segment that can code for a 44-amino-acid leader peptide, and a sequence very similar to that of the attenuator of the trp operon . RNA transcripts from several bacterial strains were studied by S1 nuclease mapping . Under conditions leading to extensive enzyme synthesis there was a large production of transcript whose 5' end correlated with the putative promoter closer to the structural genes . At low levels of operon expression there was little transcript in the extracts and both promoters appeared to serve as initiation sites . The results are interpreted in terms of transcriptional control of the pyrB-pyrI operon according to an attenuation model that differs in novel ways from the mechanisms proposed for the regulation of amino acid biosynthesis.

J Bacteriol, 1983 Mar, 153(3), 1439 - 50
Two alanine racemase genes in Salmonella typhimurium that differ in structure and function; Wasserman SA et al.; Mutations were isolated in a previously undescribed Salmonella typhimurium gene encoding an alanine racemase essential for utilization of L-alanine as a source of carbon, energy, and nitrogen . This new locus, designated dadB, lies within one kilobase of the D-alanine dehydrogenase locus (dadA), which is also required for alanine catabolism . The dadA and dadB genes are coregulated . Mutants (including insertions) lacking the dadB alanine racemase do not require D-alanine for growth unless a mutation is introduced at a second locus, designated dal . Two genes specifying alanine racemase activity were cloned from S . typhimurium . The two cloned DNA sequences do not cross-hybridize with each other; one was shown to contain the dadB gene.

J Bacteriol, 1983 Mar, 153(3), 1172 - 9
Identification of the uvrD gene product of Salmonella typhimurium LT2; Pang PP et al.; The product of the uvrD gene of Salmonella typhimurium LT2 and Escherichia coli K-12 is thought to play a role in both the correction of mismatched bases and the repair of DNA damage, since insertion mutations in the uvrD gene increase the spontaneous mutation frequency and make the cells more sensitive to killing by UV irradiation . To clone the uvrD gene of S . typhimurium, we first generated a uvrD-specific probe by using DNA from an S . typhimurium uvrD421::Tn5 mutant . This probe was used to screen a lambda library of S . typhimurium DNA . Bacteriophage carrying intact uvrD+ genes were subsequently identified, and the uvrD+ gene was subcloned onto a low-copy-number vector . By using a combination of Tn1000 insertion mutagenesis and the maxicell technique, the product of the uvrD gene was shown to be a 75,000-dalton protein, and the relative direction of transcription of this protein was determined . Introduction of a low-copy-number plasmid carrying the S . typhimurium uvrD+ gene into uvrD insertion mutants of either S . typhimurium or E . coli restored the spontaneous mutation frequency and degree of UV sensitivity to the levels in the corresponding uvrD+ strains.

Infect Immun, 1983 Mar, 39(3), 1265 - 70
Effective antibacterial protection induced by a Listeria monocytogenes-specific T cell clone and its lymphokines; Kaufmann SH; The capacity of the murine Listeria monocytogenes-specific T cell clone 9-36-1 and of lymphokines derived therefrom to induce antibacterial protection in vivo was studied . Clone 9-36-1 was stimulated to proliferate and to produce lymphokines by in vitro culture with syngeneic accessory cells and heat-killed L . monocytogenes . Although 9-36-1 cells were highly active in vitro, intravenous transfer of the cells resulted in marginal protection against a systemic infection with L . monocytogenes . In contrast, 9-36-1 cells injected subcutaneously together with L . monocytogenes into the footpad induced marked protection in syngeneic, but not in allogeneic, mice . Multiplication of Salmonella typhimurium was not reduced by the T cell clone . Studies with 51Cr-labeled T cells indicated that the low activity of intravenously transferred cells was due to an altered migration pattern . Lymphokines produced by 9-36-1 cells in vitro induced protection against L . monocytogenes in syngeneic recipient mice . Lymphokine-induced protection was also demonstrable in allogeneic recipients and against S . typhimurium . These findings suggest that the L . monocytogenes-specific T cell clone 9-36-1, although unable to immigrate into sites of bacterial deposition, had retained its ability to mobilize antibacterial defense mechanisms once present at the site of reaction.

J Med Chem, 1983 Mar, 26(3), 455 - 8
Derivatives of beta-adrenergic antagonists . N-Nitrosopropranolol and N-hydroxypropranolol and its aldonitrone; Zhang S et al.; Potential precursors to chemically reactive species derived from the beta-adrenergic antagonist propranolol were synthesized and tested for mutagenicity in the Ames Salmonella assay . N-Hydroxypropranolol (1), the corresponding aldonitrone, 3-(1-naphthoxy)-2-hydroxypropionaldehyde N-isopropylnitrone (2), and N-nitrosopropranolol (3) were prepared and tested . N-Hydroxypropranolol (1) was obtained by direct alkylation of 3-(1-naphthoxy)-1-bromo-2-propanol with N-isopropylhydroxylamine and isolated as its neutral oxalate or HBr salt . The aldonitrone (2) was obtained by mercuric oxide oxidation of the hydroxylamine . N-Nitrosopropranolol (3) was prepared by treating propranolol with nitrous acid . None of the compounds was mutagenic in the Ames assay with Salmonella typhimurium TA-98 and TA-100 strains, either in the absence or in the presence of the S-9 liver fraction from Arochlor 1254 treated rats . None of the compounds was significantly toxic to the bacteria, except for slight toxicity of the oxalate salt of 1.

Biochem Biophys Res Commun, 1983 Feb 28, 111(1), 346 - 51
Possible role of DT-diaphorase in the bioactivation of antitumor quinones; Talcott RE et al.; Menadione derivatives that are toxic to tumor cells are believed to be reduced intracellularly to species that react with DNA . In this communication, we report evidence that one of these derivatives, 3-bromomethylmenadione, is reduced by DT-diaphorases present in rat liver cytosol and in rat 9L brain tumor cells . Dicoumarol, an inhibitor of DT-diaphorases was found to inhibit both the reduction of 3-bromomethylmenadione and its mutagenicity to Salmonella typhimurium TA 97 . Homogenates of rat 9L cells were found to contain relatively high levels of DT-diaphorase, suggesting that these tumor cells may be relatively sensitive to antitumor quinones that are activated by this enzyme.

Anal Biochem, 1983 Feb 15, 129(1), 1 - 13
Complete analysis of tRNA-modified nucleosides by high-performance liquid chromatography: the 29 modified nucleosides of Salmonella typhimurium and Escherichia coli tRNA; Buck M et al.; A high-performance liquid chromatography (HPLC) method has been developed to quantify the major and modified nucleoside composition of total, unfractionated transfer RNA . The method is rapid and sensitive and offers a high degree of chromatographic resolution suitable for quantifying both stable and unstable modified nucleosides . It is nondestructive and allows the recovery of nucleosides for further characterization . We apply the method in the analysis of the 29 modified nucleosides in tRNA from Salmonella typhimurium (and Escherichia coli) and show it to be useful in examining changes in the modified nucleoside content of tRNA . Such changes may be important in regulation.

Biochem Biophys Res Commun, 1983 Feb 10, 110(3), 746 - 52
Species difference in the metabolic activation of phenacetin by rat and hamster liver microsomes; Nohmi T et al.; Phenacetin is mutagenic in Salmonella typhimurium TA 100 when liver 9,000 X g supernatant fractions from PCB-treated hamsters instead of rats are used . A mechanism of the species difference in phenacetin mutagenicity was investigated . By high-performance liquid chromatography analysis, it was found that phenacetin is activated to direct-acting mutagens through N-hydroxylation and deacetylation by hamster liver microsomes . Although no significant species difference was observed in N-hydroxylation, rates of deacetylation were 9 to 150 times higher in hamsters than in rats . The results indicate that the marked species difference in phenacetin mutagenicity is due to the difference in deacetylation activity between rat and hamster liver microsomes.

Mutat Res, 1983 Feb, 116(2), 161 - 8
Lack of genotoxic properties of the hair-dye component N-methyl-amino-2-nitro-4-N',N'-bis-(2-hydroxyethyl)-aminobenzene, in mammalian cells in vitro, and in yeasts; Loprieno N et al.; N-Methyl-amino-2-nitro-4-N',N'-bis-(2-hydroxyethyl)-aminobenzene is a hair-dye ingredient . Its potential ability to induce gene mutations, in the yeast S . pombe and in cultured mammalian CH-V79 cells, mitotic gene conversion in the yeast S . cerevisiae, and unscheduled DNA synthesis in cultured human HeLa cells was evaluated . The chemical proved unable to induce detectable genotoxic effects according to these tests . The present data, together with others that show that the chemical is not mutagenic in Salmonella typhimurium or Drosophila, and is not clastogenic in mammalian cytogenetic assays (in vitro or in vivo), strongly support the non-genotoxicity of the chemical.

J Bacteriol, 1983 Feb, 153(2), 837 - 45
Role of hypoxanthine and guanine in regulation of Salmonella typhimurium pur gene expression; Houlberg U et al.; Data are presented which indicate that the repression of pur gene expression seen after the addition of preformed purines to cultures of Salmonella typhimurium is the consequence of the presence or the formation of the purine bases, hypoxanthine and guanine . This conclusion is based on the following observations . First, it was impossible to find a correlation between the size of any individual purine nucleotide pool and the level of the first four enzymes in the de novo biosynthetic pathway . Second, adenine plus guanosine served as a perfect source of purine nucleotides, but their presence caused no repression of pur gene expression if the cells lacked purine nucleoside phosphorylase activity . This enzyme is needed to convert adenine and guanosine to hypoxanthine and guanine, but not for their conversion to nucleotides . Third, addition of guanine to a strain lacking guanine phosphoribosyltransferase (gpt) resulted in a repression of the level of the purine de novo biosynthetic enzymes, a reduction of the growth rate, and a fall in the pools of ATP and GTP . Addition of hypoxanthine to a strain lacking hypoxanthine phosphoribosyltransferase (hpt) had a similar, although weaker, effect . If the cells lacked both hypoxanthine and guanine phosphoribosyltransferases (hpt gpt), their basal level of the purine de novo biosynthetic enzymes was repressed in minimal medium . Such cells grow slower than wild-type cells and excrete purines, probably due to the inability to salvage endogenously formed hypoxanthine and guanine.

J Toxicol Sci, 1983 Feb, 8(1), 15 - 24
The production of mutagens in the intestine of mice fed on a diet containing 15% sorbic acid (I); Tsuchiya T et al.; When mice were fed on a diet containing 15% sorbic acid for a period up to 6 months, ether extracts of the intestinal contents of the mice were not mutagenic with Salmonella typhimurium TA98, but the acidic components obtained by fractionating the ether extracts, showed slightly mutagenic activity with S . typhimurium TA98, and they required the addition of liver 9,000 xg supernatant fraction for mutagenic activation . These results suggested that mutagens were gradually produced in the intestine and moved into the liver where they were metabolically activated . It is possible to presume that liver carcinoma might be attributable to the production of these mutagens.

Acta Pathol Microbiol Immunol Scand {B}, 1983 Feb, 91(1), 69 - 73
Bacterial hydrophobicity measured as partition of palmitic acid between the two immiscible phases of cell surface and buffer; Malmqvist T; Bacterial hydrophobicity was measured as the affinity of palmitic acid to the cell surface . Cell surface and buffer were regarded as two immiscible phases with different affinity for the fatty acid . After equilibration of the system, the partition quotient (PQ) between the two phases was calculated . The bacteria hydrophobicity was expressed as the amount of cell mass required to give a partition quotient of 10 between amount of fatty acid bound to cell surface and amount of fatty acid in buffer (PQ 10) . This system permits measurement of changes in hydrophobicity during bacterial growth as shown for Staphylococcus aureus, strain V 8 . The hydrophobicity of this bacterium increased 4-5 times during the exponential growth-phase of the culture . In the stationary growth-phase there was a loss of hydrophobicity, which continued for at least 48 hours, linearly with time . The system was also tested with a Salmonella typhimurium strain and its rough mutant . The results were consistent with findings in other test systems measuring the hydrophobicity of these bacteria.

Mutat Res, 1983 Feb, 107(2), 239 - 47
Influence of conjugation reactions on the mutagenicity of aromatic amines; Hongslo J et al.; 2-Acetylaminofluorene (AAF) and 2-aminofluorene (AF), as well as their N-hydroxylated metabolites, N-OH-AAF and N-OH-AF, were studied for mutagenic effects in Salmonella typhimurium with rat- and mouse-liver S9 and microsomal subfractions in the presence of cofactors for glucuronidation and glutathione (GSH) transfer . Addition of UDPGA did not affect the mutagenicity of AAF, AF or N-OH-AAF under any experimental condition . Addition of GSH, on the other hand, markedly inhibited AAF, AF and N-OH-AAF . This seemed to be due to the direct effect of GSH, and not through an enzyme-catalyzed conjugation . Further, GSH inhibited the direct mutagenicity of N-OH-AF.

Zentralbl Bakteriol Mikrobiol Hyg {A}, 1983 Feb, 253(4), 515 - 22
Competitive growth experiments with related pairs of tartrate-fermenting and tartrate-non-fermenting strains of Salmonella typhimurium: relevance to biotyping studies; Old DC et al.; For each of the isomers of tartaric acid, meso- or d- or l-, a pair of strains of Salmonella typhimurium was obtained, the one, a naturally occurring, non-fermenting strain and the other a spontaneous, tartrate-fermenting mutant derived from it . For each of the pairs of strains, competitive mixed cultures were grown from inocula of the tartrate-fermenting and tartrate-non-fermenting strains in peptone medium without or with the appropriate tartrate isomer . In each experiment, small numbers of tartrate-fermenting bacteria outgrew small or large numbers of tartrate-non-fermenting bacteria in 24 hours in tartrate-containing but not in tartrate-free peptone medium . The results of the experiments are discussed with reference to the choice of the definitive time of reading for tartrate-utilisation tests in the biotyping of S . typhimurium.

Toxicology, 1983 Feb, 26(2), 155 - 60
On the mutagenicity of metabolites derived from the mushroom poison gyromitrin; von der Hude W et al.; The hepatotoxic and carcinogenic hydrazine N-methyl-N-formyl hydrazine (MFH), which is formed from the mushroom poison gyromitrin by hydrolytic cleavage in vivo and in vitro during food processing is much more mutagenic for the strain TA 100 of Salmonella typhimurium in the presence of a metabolic activation system than in its absence . On the other hand, acetylated MFH (Ac-MFH) was not mutagenic for TA 100 in both test conditions . For the strain TA 98 neither MFH nor Ac-MFH were mutagenic both with and without metabolic activation . Therefore, a metabolic conversion of the free NH2-moiety of MFH into a genotoxic metabolite of MFH is postulated.

Can J Biochem Cell Biol, 1983 Feb-Mar, 61(2-3), 150 - 3
A novel phosphoprotein dependent on the bacterial phosphoenolpyruvate-sugar phosphotransferase system; Waygood EB et al.; A protein has been fond by isoelectricfocusing and autoradiography in Escherichia coli and Salmonella typhimurium which was phosphorylated by enzyme I and an histidine-containing phosphocarrier protein (HPr) of the phosphoenolpyruvate-sugar phosphotransferase system (PTS) . This protein was not factor III glc nor was it specifically induced by fructose . Its presence in soluble crude extracts was dependent upon growth conditions; however, the two bacteria had different patterns and amounts in respect to this novel protein . The protein was present in S . typhimurium SB2950 which has an extensive deletion through the pts operon, thus indicating that it must be coded for elsewhere on the genome.

J Gen Microbiol, 1983 Feb, 129 (Pt 2), 321 - 35
Transduction of Escherichia coli trp genes in Salmonella typhimurium and effect of N-methyl-N'-nitro-N-nitrosoguanidine on transduction with heterogenotic DNA; Mergeay M et al.; P1Kc-mediated transduction of Escherichia coli trp genes occurred at a frequency of about 10(-8) in Salmonella typhimurium trp strains carrying mutations determining sensitivity to P1 and a low level of restriction enzymes . Heterospecific transductants were analysed by using them as donors in second-stage transductions mediated by bacteriophage KBint . One class of heterospecific transductants had the phenotype Trp+ Pro- but were extremely unstable and reverted at high frequency (up to 80%) to the parental phenotype . The Trp+ Pro- phenotype probably represents insertions of the E . coli trp genes in the S . typhimurium pro genes . It was stable in a RecA background . Haploid Pl-mediated heterogenotes exhibited various degrees of homology with the trp region of S . typhimurium in KB-mediated second-stage transductions: one heterogenote (MA427), which transduced the linked markers trp, cysB and pyrF very poorly, was used to look at the effects of the mutagen N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) in stimulating heterologous recombination and to derive a method for positive selection of linked mutations . Following treatment with MNNG, heterospecific Trp+ transductants were obtained with MA427 as donor . Their yield was maximal immediately after MNNG treatment but decreased and even disappeared when transductions were carried out a few hours later . This transient process is thought to represent MNNG-induced conversion of abortive transductants to complete transductants . On the other hand, phenotypic analysis of MNNG-induced Trp+ heterologous transductants revealed the presence of mutations of various phenotypes . In particular, the antimutator phenotype was recognized in 15 clones among 110 MNNG-induced recombinants tested . However, most of these mutations seemed not to influence heterologous recombination.

Gann, 1983 Feb, 74(1), 51 - 9
In vitro metabolic activation of N,N-dibutylnitrosamine in mutagenesis; Suzuki E et al.; Enzymatic alpha-hydroxylation is believed to be the initial step in the metabolic activation of mutagenic and carcinogenic nitrosamines . Oxidative in vitro metabolism of N,N-dibutylnitrosamine (DBN) by hepatic microsomal fractions prepared from rats treated with phenobarbital and polychlorinated biphenyl (PCB) was investigated . Following incubation of DBN with the microsomal fractions, N-butyl-N-(3-hydroxybutyl)nitrosamine was identified by gas-liquid chromatography as the principal metabolite with the N-nitroso moiety, and butyraldehyde and/or two isomeric butyl alcohols (n- and sec-) were also identified and determined by gas-liquid chromatography and high-pressure liquid chromatography . The latter compounds originate from the unstable alpha-hydroxylated intermediate, N-butyl-N-(1-hydroxybutyl)nitrosamine, by spontaneous decomposition . An increased production of butyraldehyde with a concomitant enhancement of the mutagenicity of DBN toward Salmonella typhimurium TA1535 was observed when microsomes prepared from phenobarbital- and PCB-treated rats were used . SKF 525-A not only inhibited the mutagenic activation of DBN by microsomes from rats treated with the inducers but also selectively inhibited the formation of butyraldehyde and butyl alcohols from DBN . These results indicate that among the four initial hydroxylations (alpha, omega-2, omega-1, and omega) of the butyl chain demonstrated in the metabolism of DBN, alpha-hydroxylation is primarily involved in the mutagenic activation.

Zh Mikrobiol Epidemiol Immunobiol, 1983 Feb, (2), 52 - 6
{Comparative evaluation of biological properties of Salmonella typhimurium strains of different origin and genetic nature of resistance to antibiotics}; Belova TN et al.; The results obtained in the comparative study of the biological characteristics of Salmonella typhimurium strains of different origin are presented . The circulation of two biovariants differing in a number of biological characteristics, mainly in their susceptibility to antibiotics, has been shown . R-plasmids, mostly with the markers of resistance to tetracycline and with a molecular weight of 64 Md, have been isolated from "hospital" and "sporadic" strains possessing multiple antibiotic resistance.

Infect Immun, 1983 Feb, 39(2), 659 - 65
Acute iron overload in mice: pathogenesis of Salmonella typhimurium infection; Sawatzki G et al.; The bacterial growth in the tissues of C3D2F1 male mice was measured during an experimental infection with two Salmonella typhimurium strains (high virulence, strain 2386/74; low virulence, strain L15403) . This experimental model was used for evaluation of the pathogenesis in normal and iron-overloaded animals . Acute iron overload was accomplished by intramuscular injections of chelated iron (with 2,3-dihydroxybenzoic acid and citrate) with a single dose of 100 micrograms of iron per mouse . Bacteria were given intraperitoneally 1 h after the iron injection . Serum iron levels, transferrin levels, and the bacteria counts in blood and liver were measured simultaneously in all animals . There was a significant increase of bacterial growth in all tissues in the iron-treated animals . Iron abolished the normal clearance of the bacteria with low virulence from the blood . This study demonstrates that a general iron overload, as determined by an increased serum iron level, resulting from preinjection of iron, enhances bacterial growth.

Mutat Res, 1983 Feb, 119(2), 89 - 93
Toxic and mutagenic effects of formaldehyde in Salmonella typhimurium; Temcharoen P et al.; Toxic and mutagenic activities of formaldehyde were studied in Salmonella typhimurium strain TM677, using forward mutation to 8-azaguanine (8-AG) resistance both in the absence and in the presence of Aroclor-induced rat-liver postmitochondrial supernatant (PMS) . The results showed that formaldehyde was toxic and mutagenic to the bacteria in both systems, but toxicity and mutagenicity were reduced in the presence of PMS . The minimum concentration required to induce toxicity and mutagenicity was 0.17 mM in the absence of PMS and 0.33 mM in the presence of PMS.

Mutat Res, 1983 Feb, 116(2), 91 - 102
Mutagenicity of substituted phenanthrenes in Salmonella typhimurium; LaVoie EJ et al.; An extensive series of alkylated phenanthrenes was assayed for mutagenic activity in Salmonella typhimurium TA98 and TA100 . Among the alkylated phenanthrenes assayed, 1-methylphenanthrene, 9-methylphenanthrene, 1,4-dimethylphenanthrene and 4,10-dimethylphenanthrene were active as mutagens . These studies suggest that the structural requirements favoring mutagenic activity among alkylated phenanthrenes are inhibition of 9,10-dihydrodiol formation and the presence of an unsubstituted angular ring adjacent to a free peri position . The mutagenic activities of 9-fluoro-, 9-chloro-, and 9-bromo-phenanthrene were also evaluated . The positive mutagenic response of these halogenated phenanthrenes further supports the observation that inhibition of 9,10-dihydrodiol formation among substituted phenanthrenes favors mutagenic activity.

Mutat Res, 1983 Feb, 116(2), 83 - 90
Mutagenicity in Salmonella typhimurium mutants of serum extracts from airborne particulates; Ohsawa M et al.; Airborne particulates collected from urban and non-urban air were extracted with calf serum or benzene, and their mutagenic potencies were evaluated in the Salmonella reversion assay . The serum extracts were mutagenic to strains TA98 and TA100 and contained both direct- and indirect-acting mutagens . Mutagenic activities for TA98 recovered from the particulates by serum or benzene extraction were much less in the serum extracts than in the benzene extracts . There was no significant difference in mutagenic potencies of the extracts between the urban and non-urban particulates, irrespective of the presence of S9 mix . The calculated mutagenic activities per m3 of air, however, were greater for urban air than for non-urban air, because of higher concentration of particulates in urban air than in non-urban air . Serum effectively reduced both direct and indirect mutagenic activities of the benzene extracts except for an insufficient reduction in direct mutagenicity at a high dose of benzene extracts . These findings suggest that serum could contribute greatly to decrease the mutagenicity of airborne particulates by mechanisms such as less efficient solubilization of mutagenic components and inactivation by protein binding . Biological availability of mutagens, therefore, should be considered for evaluation of actual mutagenic hazard by airborne particulates.

Mutat Res, 1983 Feb, 116(2), 155 - 9
Mutagenic evaluation of the monocyclic aromatic amine N-methylamino-2-nitro-4-N', N'-bis(2-hydroxyethyl)-aminobenzene in the Salmonella typhimurium/mammalian microsome test; Shahin MM et al.; The hair-dye component N-methylamino-2-nitro-4-N', N'-bis(2-hydroxyethyl) aminobenzene was investigated for mutagenic activity in Salmonella typhimurium strains TA1535, TA100, TA1537, TA1538 and TA98 . The testing was performed in the absence and in the presence of a rat-liver microsomal activation system induced by Aroclor 1254 . Our results indicate that N-methylamino-2-nitro-4-N', N'-bis(2-hydroxyethyl)aminobenzene does not induce mutations in Salmonella typhimurium strains, either in the absence or in the presence of the metabolic activation system . The purity of the compound was controlled by utilizing high-pressure liquid chromatography (HPLC) and thin-layer chromatography (TLC).

Mutat Res, 1983 Feb, 116(2), 103 - 17
Mutagenic activities of gentisin and isogentisin from Gentianae radix (Gentianaceae); Morimoto I et al.; The mutagenic activities of 2 hydroxyxanthones, gentisin and isogentisin, obtained from the methanol extract of Gentianae radix (Gentianaceae) were investigated . The methanol extract of Gentianae radix, which showed mutagenicity in the Ames test in Salmonella typhimurium strain TA100 with S9 mix, was fractionated by column chromatography on Sephadex LH-20, and the fractions were purified by preparative TLC and column chromatography on polyamide . 2 mutagenic materials thus obtained, S1 and S2, each gave a single band on TLC . Identification of S1 and S2 was accomplished by comparing the analytical (mps, elementary analyses) and spectral (UV, IR, mass, NMR) results for S1 and S2 with literature data for gentisin and isogentisin . At doses below 10 micrograms, S1 (gentisin) and S2 (isogentisin) had similar specific mutagenic activities . At doses of over 10 to 50 micrograms, the mutagenic activities of S2 and S1 were 19.1 and 6.94 revertants per microgram respectively . This much lower activity of S1 than S2 may be a result of its poor solubility owing to the presence of the OMe group at C-3 . The combined yield of S1 and S2 was about 76 mg (40 mg as S1 and 36 mg as S2), which accounted for 76% of the content of mutagenic compounds (100 mg) estimated roughly from the total mutagenic activity in the extract of the starting materials (100 g).

Mutat Res, 1983 Feb, 113(1), 13 - 9
The effect of different genetic properties of Salmonella typhimurium on the determination of stabilities and mutagenic concentrations of chemical carcinogens using the diffusion bioassay; Awerbuch TE et al.; The mathematical model used to calculate half-life and mutagenic concentrations of chemical carcinogens from the diffusion bioassay does not include any terms related to the nature of the microorganism used in the assay (Awerbuch et al., 1979; Awerbuch and Sinskey, 1980) . In this work we tested the model with different strains of Salmonella typhimurium . These strains are auxotrophs for histidine and are sensitive to base-pair substitution . The half-life (tau 1/2) of N-methylN'-nitro-N-nitrosoguanidine (NG) was calculated by the diffusion assay, using strains hisG46, TA1950, TA1535 and TA100 as the bacterial indicators . For all strains tau 1/2 equalled 2.2 h; strain sensitivity for detecting threshold mutagenic concentrations of NG was essentially the same, except that hisG46 was slightly more sensitive.

J Infect Dis, 1983 Feb, 147(2), 210 - 6
A hospital outbreak of multiresistant Salmonella typhimurium belonging to phage type 193; Robins-Browne RM et al.; An outbreak of nosocomial infection was caused by strains of Salmonella typhimurium phage type 193 that were resistant to ampicillin, chloramphenicol, neomycin-kanamycin, streptomycin, spectinomycin, sulfonamides, tetracyclines, trimethoprim, and nalidixic acid . Resistances to drugs other than nalidixic acid were specified by plasmids, and, on the basis of phage typing and plasmid characterization studies, the multiresistant phage type 193 strains were determined to be clonal . In a two-year period, 488 patients infected with these bacteria were identified . An investigation in a pediatric surgical ward, where the outbreak was particularly severe, showed that patients exposed to antibiotics were more likely to be colonized with the epidemic strain and that young debilitated patients were more liable to show clinical signs of infection . Epidemiologic studies suggested that cross infection via the hands of the ward staff was the likely means of propagation of the epidemic.

J Hyg (Lond), 1983 Feb, 90(1), 55 - 60
Plasmid-encoded trimethoprim resistance in salmonellas isolated in Britain between 1970 and 1981; Threlfall EJ et al.; Trimethoprim resistance was plasmid-encoded in all trimethoprim-resistant Salmonella typhimurium and in the majority of trimethoprim-resistant salmonellas of other serotypes isolated since 1970 from humans and food animals in Britain . In S . typhimurium, non-autotransferring plasmids of compatibility group 3 and autotransferring plasmids of group H2 predominated . The predominance of these plasmid types has resulted from the spread of clones of trimethoprim-resistant strains of phage types 18, 170 and 204c . In other salmonellas, a variety of plasmid compatibility groups have been identified . Almost all plasmids which conferred resistance to trimethoprim also coded for sulphonamide resistance.

J Bacteriol, 1983 Feb, 153(2), 998 - 1007
Regulation of Escherichia coli aspartate transcarbamylase synthesis by guanosine tetraphosphate and pyrimidine ribonucleoside triphosphates; Turnbough CL Jr; The effects of guanosine tetraphosphate (ppGpp) and pyrimidine ribonucleoside triphosphates on Escherichia coli aspartate transcarbamylase (ATCase) synthesis were examined . To determine the effect of ppGpp, a stringent (relA+) and relaxed (relA) isogenic pair of E . coli K-12 strains was starved for isoleucine, and the residual rate of synthesis of this enzyme was measured . It was necessary to starve the strains for uracil before the isoleucine limitation to maintain similar, low levels of UTP, the putative pyrimidine effector of ATCase synthesis . The isoleucine starvation of the stringent strain caused an immediate 10-fold increase in the intracellular concentration of ppGpp, which was coincident with the cessation of the synthesis of the enzyme . The elevated level of ppGpp then decayed until it reached an intracellular concentration similar to that found in unstarved cells . Enzyme synthesis resumed at this time . In the relaxed strain, the intracellular concentration of ppGpp did not increase upon isoleucine starvation and synthesis of the enzyme was not repressed . These experiments strongly indicated that ppGpp acts as a negative effector of ATCase synthesis . The repression of ATCase synthesis by ppGpp was demonstrated directly by using a Salmonella typhimurium (relA) in vitro coupled transcription-translation system with a lambda specialized transducing phage carrying the E . coli K-12 operon encoding the subunits of this enzyme (pyrBI) as a source of DNA . This in vitro system was also used to measure the effects of UTP and CTP on ATCase synthesis . Increasing the concentration of UTP in the in vitro reaction mixture resulted in strong repression of this synthesis, whereas increasing the CTP concentration did not affect synthesis significantly . Possible mechanisms for the regulation of pyr gene expression, including attenuation control, are discussed.

J Immunol, 1983 Feb, 130(2), 903 - 7
Natural and antibody-dependent cell-mediated activity against Salmonella typhimurium by peripheral and intestinal lymphoid cells in mice; Nencioni L et al.; Cell-mediated immune responses were assessed employing a 2-hr in vitro cytotoxicity assay against S . typhimurium . It was observed that lymphocytes from GALT as well as from peripheral lymphoid organs possessed natural antibacterial activity, whereas macrophages were devoid of this spontaneous activity . The distribution of this newly described natural activity was PPL greater than MnL greater than IEL = SpL = PBL greater than PoL; this did not correlate with the organ distribution of NK activity against YAC-1 tumor cells, which was PBL greater than SpL = IEL greater than MnL = PoL = PPL . Moreover, the phenotype of the splenic effector cell of the natural activity against S . typhimurium showed some differences from that of NK activity . In fact, both these cells were asialo GM1+, Fc-receptor+, nonadherent, and nonphagocytic, but the former was Thy-1.2- and the latter Thy-1.2+ . The effector cell of the natural antibacterial activity in the Peyer's patches had the same phenotype as the splenic one . It was then observed that the antibacterial activity could be augmented by the addition of immune antibodies against S . typhimurium . This was particularly evident employing IEL, SpL, and PBL as effector cells, whereas PPL and MnL did not show any antibody-dependent antibacterial activity . Furthermore, these last two populations could not mediate ADCC against CRBC . Employing selective methods to deplete cell populations, we observed that, at least at the splenic level, there is also a cell that differs in its phenotypic characteristics from that mediating natural antibacterial activity but that plays a role in the antibody-dependent reactions . In conclusion, these results suggest that natural and antibody-dependent antibacterial mechanisms might be important in defense against S . typhimurium, particularly at the gastrointestinal level, where many bacterial infections first take place and begin to interact with the host immune system.

Cancer Res, 1983 Feb, 43(2), 653 - 9
Mutagenic response of Ames strains cured of their inducible Fels 1 and Fels 2 prophages; Affolter M et al.; Ames strain TA100 was cured of its Fels 1 and Fels 2 prophages to yield the corresponding nonlysogenic derivative designated TAQ100 . The two monolysogenic strains corresponding to TA100 lysogenic for Fels 1 (TAQ100F1) and for Fels 2 (TAQ100F2) were also isolated . In addition, the equivalent strains lacking pKM101 and designated TAQ1535, TAQ1535F1, and TAQ1535F2 were obtained . Ames strains TA98 and TA1538 are lysogenic for Fels 2 and were observed by colony hybridization to contain cryptic Fels 1 DNA sequences . Strains corresponding to TA98 and TA1538 cured of Fels 2 were isolated and designated TAQ98F1d and TAQ1538F1d, respectively . Fels 1 grew poorly on Fels 1-cured strains, and Fels 2 grew not at all on Fels 2-cured strains . The cured strains had therefore to be identified as such by their failure to react in colony hybridization with 32P-labeled probes of Fels 1 and/or Fels 2 DNA . The specificity of the labeled probes was confirmed with the aid of the nonlysogenic Salmonella typhimurium strain Q1 and its two monolysogenic derivatives Q1 (Fels 1) and Q1 (Fels 2) . The cured strains were found to respond in the same manner as did the standard Ames strains to a variety of well-known mutagens, including aflatoxin B1, 7, 12-dimethylbenz(a)anthracene, daunorubicin, 2-amino-dipyrido{1,2-a:3',2'-d}imidazole, and beta-naphthylamine . Also, mitomycin C, bleomycin, and diethylstilbestrol were nonmutagenic to TAQ100 and TAQ98F1d as they are to TA100 and TA98 . Since the Fels prophages are inducible by aflatoxin B1, by daunorubicin, and by other agents, it seems that mutagenesis and Fels prophage induction occur in separate subpopulations of cells; this situation had previously been reported to occur for mutagenesis and prophage lambda induction in Escherichia coli . In any case, the Fels prophages appear to have no major influence on the mutagenic response of the Ames strains.

J Bacteriol, 1983 Feb, 153(2), 830 - 6
Genetic map of the opp (Oligopeptide permease) locus of Salmonella typhimurium; Higgins CF et al.; The uptake of peptides by Salmonella typhimurium is mediated by three apparently independent transport systems . One of these systems, the oligopeptide permease, is encoded by a genetic locus (opp) which has been mapped at 34 min on the S . typhimurium chromosomal map . We accurately mapped the location of opp by cotransduction frequencies and by deletion analysis and show that the gene order for this region of the chromosome is cysB-trp-tonB-opp-galU-tdk . All opp mutants, independently isolated by a variety of means, mapped at this one locus, between tonB and galU . Spontaneous and transposon Tn10-generated deletions were used to construct a fine-structure genetic map of opp . Evidence is presented which indicates that opp covers a 5- to 6-kb segment of DNA and is therefore likely to consist of more than one gene.

J Bacteriol, 1983 Feb, 153(2), 1114 - 9
Internal promoters of the his operon in Salmonella typhimurium; Schmid MB et al.; Two internal promoters in the his operon of Salmonella typhimurium have been precisely mapped genetically . The internal promoters are found in, or very close to, gene border regions in the his operon . The his operon was examined for the presence of additional internal promoters whose transcripts were sensitive to rho-mediated transcription termination and therefore had escaped detection . No new internal promoters were found . It is argued that the internal promoters described here are not likely to be fortuitous message start sites, but may play a physiologically important role in operon expression.

Zh Mikrobiol Epidemiol Immunobiol, 1983 Feb, (2), 84 - 6
{Characteristics of hydrolysis of lipopolysaccharide and Boivin antigen isolated from Salmonella typhimurium}; Iankina NF et al.; The work deals with the isolation of serologically active polysaccharide from S . typhimurium 415 . Particular attention is paid to different conditions for the hydrolysis of lipopolysaccharide (LPS) and Boivin's antigen, permitting the authors to obtain polysaccharides with different activity of the determinant groups . The action of 1% acetic acid on LPS, lasting for several hours, did not result in the hydrolysis of the antigen, while its hydrolysis in 1.5% acetic acid led to the decomposition of the greater part of the determinant groups . Polysaccharide isolated from Boivin's antigen after hydrolysis in 1% acetic acid retained the specific activity of all antigenic determinants of the natural biopolymer.

J Mol Biol, 1983 Jan 25, 163(3), 377 - 94
Transcription attenuation is the major mechanism by which the leu operon of Salmonella typhimurium is controlled; Searles LL et al.; Three mutations, each causing constitutive expression of the Salmonella typhimurium leu operon, were cloned into phage vector lambda gt4 on EcoRI DNA fragments carrying all of that operon except for part of the promoter-distal last gene . Sequence analysis of DNA from these phage demonstrated that each contains a single base change in the leu attenuator . Transcription of mutant DNA in vitro resulted in transcription beyond the usual site of termination . The level of beta-IPM dehydrogenase, the leuB enzyme, was elevated 40-fold in a strain carrying one of these mutations, and starvation of this strain for leucine had little effect on the amount of activity expressed . Using a strain with a wild-type promoter-leader region of the leu operon, the rates of synthesis and degradation of leu leader RNA and readthrough RNA (leu mRNA) were measured by DNA-RNA hybridizations with specific DNA probes . The rate of synthesis of the leu leader was about the same in cells grown with excess or with limiting leucine . On the other hand, the rate of synthesis of leu mRNA was 12-fold higher for cells grown in limiting leucine as opposed to excess leucine . The rate of degradation of these RNA species was the same under both conditions of growth . Thus, the variation in expression of the leu operon observed for cells grown in minimal medium is, for the most part, not caused by control over the frequency of initiation or by the differential stability of these RNA species . Rather, the variation is a direct result of the frequency of transcription termination at an attenuator site . These results taken together suggest that transcription attenuation is the major mechanism by which leucine regulates expression of the leu operon of S . typhimurium for cells growing in a minimal medium.

J Biol Chem, 1983 Jan 10, 258(1), 629 - 35
Effect of altered lipid A synthesis on the synthesis of the OmpA protein in Salmonella typhimurium; Rick PD et al.; The effect of altered lipid A synthesis on the synthesis of the OmpA protein was investigated in mutants of Salmonella typhimurium possessing a temperature-sensitive defect in 3-deoxy-D-manno-octulosonate (2-keto-3-deoxyoctonate) synthesis . The defect is due to a mutation in the structural gene for 3-deoxy-D-manno-octulosonate-8-phosphate synthetase (designated kdsA), and expression of this lesion results in the accumulation of an incomplete precursor of lipid A (Rick, P.D., and Osborn, M.J . (1977) J . Biol . Chem . 252, 4895-4903) . Pulse labeling studies revealed a pronounced transient increase in the rate of OmpA synthesis following a shift of mutants to nonpermissive conditions . The rate of OmpA synthesis increased about 2.5-fold at 20-30 min following a shift to 42 degrees C and then decreased over the next 30-40 min . A similar but less pronounced increase in the apparent rate of synthesis of the 34-kilodalton porin protein was also observed . In contrast, the rates of synthesis of total cell envelope protein, as well as that of the 35 and 36-kilodalton porin proteins, were relatively unaffected . The effect of increased temperature on the rate of OmpA synthesis was specifically related to expression of the kdsA lesion; it was not found to be strain-specific or uniquely related to expression of a single kdsA mutant allele.

FEBS Lett, 1983 Jan 10, 151(1), 59 - 62
Cyclic AMP-independent phosphorylation of Escherichia coli isocitrate dehydrogenase; Malloy PJ et al.; The phosphorylation of NADP-specific isocitrate dehydrogenase in a wild-type and in an adenylate cyclase deletion mutant of Escherichia coli has been investigated . The results obtained clearly indicate that cyclic AMP is not required for the phosphorylation reaction per se, not is it for the synthesis or possible activation of the phosphoprotein kinase in this organism . This data are in contrast to results observed in Salmonella typhimurium, and indicate that important differences exist in the phosphorylation of the isocitrate dehydrogenase in these two organisms.

J Gen Virol, 1983 Jan, 64 (Pt 1), 199 - 205
Genetic studies of hybrids between coliphage phi 80 and Salmonella phage P22; Yamamoto N et al.; Hybrids between Escherichia coli phage phi 80 and Salmonella typhimurium phage P22 were isolated after superinfection by P22 of a smooth E . coli-S . typhimurium hybrid lysogenic for phi 80 . These hybrid phages, designated phi 80immP22 and phi 80immP22dis, possessed the phi 80 protein coat and tail genes . The phi 80immP22 hybrids acquired the immunity (immC) region of P22 and some adjacent P22 genes, but E . coli-S . typhimurium strains lysogenic for phi 80immP22 hybrids remained sensitive to P22 . The phi 80immP22dis hybrids, found ten times more frequently than the phi 80immP22 hybrids, contained a more extensive portion of the P22 genome which encompassed the immI as well as the immC region of P22 . Therefore, the phi 80immP22dis hybrids conferred on their hosts immunity to P22 infection . Further analyses have revealed that the phi 80immP22dis hybrids carry the P22 attachment region and either P22 tail gene 9 or antigen conversion gene a1, but not both of these genes.

Prog Food Nutr Sci, 1983, 7(3-4), 19 - 28
Survival rate of Salmonella and Shigella in fermented milk products with and without added human gastric juice: an in vitro study; Alm L; The survival rates of Salmonella agona, Salmonella java, Salmonella typhimurium and Shigella sonnei in milk and fermented milk products were investigated with and without the addition of human gastric juice during a 7 to 10 hour test period . It was found that yoghurt inhibited the growth of Salmonella and Shigella very effectively even when the yoghurt had been heated to 100 degrees C for 15 minutes, whereas milk and the other fermented milk products showed a lower ability to inhibit the growth of pathogens . Yoghurt plus human gastric juice greatly depressed the growth rate of the pathogens; after 30 minutes no more colonies were formed . Even kefir or ropy milk plus gastric juice showed inhibition of Salmonella typhimurium after one hour . In the case of acidophilus milk plus gastric juice, the inhibition of Salmonella typhimurium occurred first after 2.5 hours and the presence of viable Shigella sonnei was noticed for 4 hours . The addition of physiological NaCl instead of human gastric juice to the fermented milk samples before inoculation changed the picture of the survival rate . Only yoghurt inhibited the growth of Salmonella java after 30 minutes; Shigella sonnei survived in yoghurt for 4 hours and in the other fermented milk samples for 5 hours . It can be assumed that yoghurt contains some antimicrobial compounds that inhibit the growth of pathogens and that this inhibiting property is enhanced by the addition of human gastric juice.

Environ Mutagen, 1983, 5(6), 803 - 11
The induction of bacterial mutation and hepatocyte unscheduled DNA synthesis by monosubstituted anilines; Thompson CZ et al.; A group of 45 monosubstituted aniline compounds was tested for the induction of point mutations in Salmonella typhimurium and Escherichia coli as well as for unscheduled DNA synthesis (UDS) in rat hepatocyte culture . Eleven compounds were bacterial mutagens, and five compounds induced UDS . Among these a correspondence between mutagenicity and UDS occurred for only two compounds (o-phenylenediamine and 4-aminobiphenyl), and these were also reported to be carcinogenic in rodents . Bacterial mutation was observed for one compound (p-phenylenediamine) not carcinogenic in rodents, and six suspect carcinogens were not detected in either test . In addition, eight compounds of unknown carcinogenic potential induced either bacterial mutation or UDS.

Nutr Cancer, 1983, 5(2), 87 - 91
Correlation of mutagenicity and tumorigenicity of betel quid and its ingredients; Shirname LP et al.; The mutagenic activity of betel quid and its ingredients was determined using Salmonella typhimurium tester strains TA 100, TA 1535, TA 98, and TA 1538, both in the presence and absence of S9 mixture . Aqueous extracts of betel quid (BQ), betel quid with tobacco (BQT), and betel nut (BN) were mutagenic in strain TA 100 . Aqueous extract of betel leaf (BL) was not mutagenic in any of the four strains . Arecoline and arecaidine, which are major alkaloids present in BN, were mutagenic in all four tester strains . Tumorigenicity studies in Swiss mice given the above constituents showed that BN and BQ induced lung tumors (47% and 26%, respectively) . However, when BN was fed with BL, tumorigenicity was lowered to 38% . BL alone was not tumorigenic . Thus, the mutagenicity of betel quid and its ingredients is correlated with tumorigenicity.

Med Microbiol Immunol (Berl), 1983, 171(4), 199 - 202
The role of macrophages in acquired cell-mediated immunity to Toxoplasma gondii; Hof H; Mice immunized by primary infection with an avirulent strain of Toxoplasma gondii were protected against challenge infection with a highly virulent strain, even though macrophages were eliminated either by dextran sulfate or by carbon ink . This findings differs strikingly from previous results obtained in similar experiments with other intracellular pathogens such as Listeria monocytogenes and Salmonella typhimurium . It is therefore concluded that the macrophage population, which plays an essential role in the cell-mediated immunity to reinfection with L . monocytogenes and S . typhimurium, is not of primary importance in cell-mediated immunity to reinfection with T . gondii.

C R Seances Acad Sci III, 1983, 296(7), 363 - 8
{Specificity in the relationship between Salmonella typhimurium and Schistosoma mansoni}; Bouillard C et al.; Special interaction between Salmonella typhimurium (STM) and Schistosoma mansoni is considered under two complementary aspects, in vivo and in vitro, using scanning and transmission electron microscopy . The resulting observations have obviously permitted us to discover a large specificity in these adhesion phenomena that seems to lead to the fusion of membranes between the two organisms . Microanalysis trials executed in these areas of strong affinity were attempted.

Can J Biochem Cell Biol, 1983 Jan, 61(1), 29 - 37
Determination of the levels of HPr and enzyme I of the phosphoenolpyruvate-sugar phosphotransferase system in Escherichia coli and Salmonella typhimurium; Mattoo RL et al.; The levels of histidine-containing protein HPr and enzyme I of the phosphoenolpyruvate-sugar phosphotransferase system of Escherichia coli strains 1100, NC3, W3110, and P650 and Salmonella typhimurium strains SB3507 and LJ144 have been determined by quantitative sugar phosphorylation assay and immunochemically . The levels have been determined for cells grown on minimal salts with glucose, fructose, mannitol, glycerol, and lactate and on nutrient broth . All determinations indicate a two- to three-fold change in the levels of enzyme I and HPr between growth on hexoses, which gave the higher levels, and the other growth substrates . The highest levels were not always found in glucose-grown cells . Antibodies were produced in rabbits using purified proteins from E . coli P650 . The activity measurements and immunochemically determined enzyme I protein gave specific activities in the crude extracts of E . coli strains which were similar to that of the pure enzyme . The wild-type S . typhimurium enzyme I in crude extracts did not have the same immunochemical reactivity, although there was a considerable cross-reaction and the specific activity appeared to be half that of pure enzyme I . The HPr from both E . coli and S . typhimurium behaved identically and, although the immunoprecipitation was weak, it did indicate that HPr assays may not be as reliable as the enzyme I assays . The relative amounts of enzyme I and HPr found indicate that there are between 10- and 20-fold more HPr molecules in a cell than enzyme I subunits which form active dimers.

Cancer Immunol Immunother, 1983, 14(3), 202 - 4
Synergistic anti-tumor effect of mini-cells prepared from Salmonella typhimurium with mitomycin C in EL4-bearing mice; Kurashige S et al.; A statistically significant increase in survival time was observed in EL4-bearing mice after a mini-cell inoculation . However, no case of survival for over 30 days was observed after an EL4 graft in mice treated with mini-cells alone . Fifty percent of the mice survived for 40 days after an EL4 transplantation when the mice were treated with both an IV injection of mini-cells and an SC injection of mitomycin C . The mini-cell injection restored the macrophage chemotaxis activity in EL4-bearing mice but did not restore the lymphocyte activities.

Poult Sci, 1983 Jan, 62(1), 30 - 7
The influence of a feed additive level of virginiamycin on the course of an experimentally induced Salmonella typhimurium infection in broilers; Abou-Youssef MH et al.; The purpose of this study was to determine the effect of virginiamycin on the course of an experimentally induced infection of Salmonella typhimurium in broilers . Several parameters were evaluated, including effects on the persistence and duration of shedding of the infecting Salmonella organism and its antibiotic resistance patterns . Virginiamycin was administered to the experimentally infected group for 8 weeks in feed at concentrations of 25 g/ton . This was compared to an infected control group not receiving the antibiotic . No effects were exhibited by virginiamycin on Salmonella typhimurium shedding and antibiotic resistance patterns.

Carcinogenesis, 1983, 4(2), 157 - 60
The effect of substituents in the aromatic ring on carcinogenicity of N-nitrosomethylaniline in F344 rats; Kroeger-Koepke MB et al.; N-Nitroso-N-methylaniline (NMA) and N-nitroso-N-methyl-4-fluoroaniline (p-F-NMA), both non-mutagenic in Salmonella typhimurium and N-nitroso-N-methyl-4-nitroaniline (p-NO2-NMA), a potent mutagen, were tested for carcinogenicity in F344 rats . NMA was shown to induce a high level of tumors in the upper gastrointestinal tract, particularly in the esophagus . Male rats treated with NMA died with tumors at a slightly higher rate than females, although the final tumor yield was the same . Most of the rats treated with p-F-NMA also developed tumors of the esophagus, but they died less rapidly than the NMA treated rats, indicating that p-F-NMA is a slightly weaker carcinogen than NMA . The powerful, directly acting mutagen, p-NO2-NMA did not appear to induce tumors at all since its tumor spectrum was essentially identical to that of the untreated control rats . Thus, the carcinogenic activities of NMA and its substituted analogs do not appear to correlate with bacterial mutagenesis assays . Additionally, NMA, p-F-NMA and N-nitroso-N-methyl-4-bromoaniline, the last a strong mutagen in S . typhimurium, were shown not to induce sister chromatid exchanges in CHO cells and in a clone of a CHO:liver cell hybrid which had previously been shown to be sensitive to chemical agents which require metabolic activation.

Appl Environ Microbiol, 1983 Jan, 45(1), 174 - 81
Bacterial survival and association with sludge flocs during aerobic and anaerobic digestion of wastewater sludge under laboratory conditions; Farrah SR et al.; The fate of indicator bacteria, a bacterial pathogen, and total aerobic bacteria during aerobic and anaerobic digestion of wastewater sludge under laboratory conditions was determined . Correlation coefficients were calculated between physical and chemical parameters (temperature, dissolved oxygen, pH, total solids, and volatile solids) and either the daily change in bacterial numbers or the percentage of bacteria in the supernatant . The major factor influencing survival of Salmonella typhimurium and indicator bacteria during aerobic digestion was the temperature of sludge digestion . At 28 degrees C with greater than 4 mg of dissolved oxygen per liter, the daily change in numbers of these bacteria was approximately -1.0 log10/ml . At 6 degrees C, the daily change was less than -0.3 log10/ml . Most of the bacteria were associated with the sludge flocs during aerobic digestion of sludge at 28 degrees C with greater than 2.4 mg of dissolved oxygen per liter . Lowering the temperature or the amount of dissolved oxygen decreased the fraction of bacteria associated with the flocs and increased the fraction found in the supernatant.

J Bacteriol, 1983 Jan, 153(1), 357 - 63
Effects of the hisT mutation of Salmonella typhimurium on translation elongation rate; Palmer DT et al.; The hisT mutation in Salmonella typhimurium which results in loss of pseudouridine base modifications in the anticodon regions of many tRNAs was shown to reduce the rate of protein synthesis in vivo by about 20 to 25% as compared with that measured in hisT strains . Reduced protein synthesis rate occurred predominantly at the level of translation rather than transcription . Increased sensitivity of hisT mutants to growth inhibition by antibiotics that inhibit translation elongation, but not by those that inhibit translation initiation, transcription initiation, or transcription elongation, indicates that the hisT mutation leads to a defect in one or more of the steps in the polypeptide chain elongation mechanism . These results can account for effects of the hisT mutation on regulation of certain amino acid biosynthetic operons, including the his, leu, and ilv operons.

J Bacteriol, 1983 Jan, 153(1), 33 - 44
Mutagenesis, by methylating and ethylating agents, in mutH, mutL, mutS, and uvrD mutants of Salmonella typhimurium LT2; Shanabruch WG et al.; Salmonella typhimurium LT2 mutH, mutL, mutS, and uvrD mutants were especially sensitive to mutagenesis by both the recA+-dependent mutagen methyl methane sulfonate and the recA+-independent mutagen ethyl methane sulfonate, but not to mutagenesis by agents such as 4-nitroquinoline-1-oxide and UV irradiation . Similarly, these mutator strains were very sensitive to mutagenesis by the methylating agents N-methyl-N'-nitro-N-nitrosoguanidine and N-methyl-N-nitrosourea . The increased susceptibility to mutagenesis by small alkylating agents due to mutH, mutL, mutS, and uvrD mutations was not accompanied by an increased sensitivity to killing by these agents . Various models are discussed in an effort to explain why strains thought to be deficient in methyl-instructed mismatch repair are sensitive to mutagenesis by methylating and ethylating agents.

Ultrasound Med Biol, 1983, Suppl 2, 49 - 53
Investigation into the possible genetic effects of diagnostic ultrasound; Wegner RD et al.; The mutagenic effect of DUS (diagnostic ultrasound) was examined using two generators emitting continuous waves and pulsed waves, respectively . Three different test systems for mutagenic activity were employed in this study . 1 . The frequency of sister chromatid exchanges (SCEs) was determined in metaphase chromosomes of human lymphocytes and of Chinese hamster ovary (CHO) cells sonicated at different stages of the cell cycle . 2 . The induction of DNA single strand breaks was tested in CHO cells treated with continuous wave ultrasound . Following sonication an endonuclease was introduced into the cells converting single strand breaks to chromosomal aberrations scorable in the following metaphase . 3 . The influence of DUS on the number of point mutations was evaluated in the Ames test . A tester strain of Salmonella typhimurium indicating base substitutions was sonicated . At the present stage, all results proved to be completely negative and could thus not support the view of any mutagenic activity of diagnostic ultrasound.

Ultrasound Med Biol, 1983, Suppl 2, 45 - 8
Is pulsed ultrasound mutagenic?
Barnett SB, Baker RS, Barnstable S.
The possibility that microsecond pulses of 3 MHz ultrasound may interact at the cellular level, with genetic consequences, was investigated using two different endpoints . The Ames mammalian microsome test was employed to assess mutagenicity and viability in Salmonella typhimurium bacteria, while the sister chromatid exchange frequency provided an indicator of ultrasound induced effects at the chromosome level in Chinese hamster ovary cells.

G Batteriol Virol Immunol, 1983 Jan-Jun, 76(1-6), 57 - 61
{Biological effects of laser radiation and methylene blue on a strain of Salmonella typhimurium (TA 100) (II)}; Pasquetto N et al.; In this second note, the AA . have studied biological effect of laser radiation and methylene blue on Salmonella typhimurium TA 100 strain with greatest susceptibility for mutagenetic agents . Their results show a biological effect of laser radiation, of methylene blue like to those obtained for TA 1538 strain, nevertheless greatest susceptibility of TA 100 strain because carrier of plasmid.

G Batteriol Virol Immunol, 1983 Jan-Jun, 76(1-6), 48 - 56
{Biological effects of the combined action of laser radiation and methylene blue on a strain of Salmonella typhimurium (TA 1538) (I)}; Curci E et al.; The AA . have studied biological effects of laser radiation and methylene blue (MB) on Salmonella typhimurium TA 1538 strain . Their results show low lethal effect of laser radiation directly proportional to administered dose . This effect is more evident in the only MB treatment . Lethal effect persisted, although non directly proportional with combined treatment laser and MB . Some treatments have not demonstrated mutagenetic effect . A new set of trials they are making on Salmonella typhimurium TA 100 strain with plasmid pK M 101 that give to strain greatest susceptibility for mutagenetic agents.

Pediatr Pharmacol (New York), 1983, 3(3-4), 175 - 80
The benefits of drug monitoring in patients with bacterial meningitis, eg, chloramphenicol monitoring; Rosin H et al.; Regular drug monitoring during therapy with chloramphenicol sodium succinate is actually recommended by expert centers . In this report a case of meningitis due to Salmonella typhimurium is described, which underlines the necessity of examining both the chloramphenicol and the chloramphenicol succinate concentrations . It is suggested that medical microbiologists and clinicians should be encouraged to take advantage of new, quick, and sensitive methods for drug monitoring in order to achieve optimal therapy.

Nutr Cancer, 1983, 5(3-4), 146 - 51
Mutagenic activity of heated potato/oil systems; Osman A et al.; Mutagens detected with Salmonella typhimurium strain TA 98 in the presence of liver S9 mix were extracted from potato slices, but not pure potato starch, after frying in oil . No mutagenic activity was detected using strain TA 100, in the presence or absence of S9 mix with either fried potato slices or potato starch . Mutagenic activity was detected at frying temperatures of 140 degrees C and above . The mutagenic activity was limited to the outer portion of the fried potato slices and increased with frying time and temperature . Mutagenic activity ratios for extraction with both (NH4)2SO4/NH4OH and Na2SO4/NaOH were similar.

Acta Chem Scand B, 1983, 37(7), 629 - 38
Synthesis of disaccharides related to the O-specific polysaccharide of Salmonella typhimurium; Bock K et al.; Methyl 2-O-benzyl-4,6,-O-benzylidene-alpha-D-mannopyranoside (13) has been glycosylated with 3,6-dideoxy-2,4-di-O-p-nitrobenzoyl-alpha-D-xylo-hexopyranosyl bromide (4) and its enantiomer (5) using mercury cyanide as catalyst and toluene and nitromethane as solvent . The anomeric ratio has been determined by 1H NMR spectroscopy and is reversed going from the D to the L compound . Glycosylation of 13 with 2-O-benzyl-3,6-dideoxy-4-O-p-nitrobenzoyl-alph-D-xylo-hexopyranosyl bromide (9) under similar reaction conditions gives exclusively the alpha-linked disaccharide while glycosylation using 2,4-di-O-benzyl-3,6-dideoxy-alpha-D-xylo-hexopyranosyl chloride (12) gives a 1:3 mixture of beta- and alpha-linked disacchrides . Glycosylation of 13 with 12, catalyzed by tetrabutylammonium bromide at elevated temperature, yields exclusively the alpha-linked disaccharide . The conformation of two of the deprotected disaccharides has been determined using hard sphere calculations and high field NMR data.

Z Parasitenkd, 1983, 69(6), 797 - 805
Host specificity in mice selected for innate immunity to Nematospiroides dubius: infections with Nippostrongylus brasiliensis, Mesocestoides corti and Salmonella typhimurium; Brindley PJ et al.; The selection of mice for innate immunity to Nematospiroides dubius was not specific . Mice bred as refractory (R) to N . dubius infection were more refractory to primary infections with Nippostrongylus brasiliensis than other mice bred as liable (L) to infection with N . dubius . R and L, as well as randomly-bred (Rd) and inbred C3H mice were all immune to challenge infection with N . brasiliensis . Previous infections with N . brasiliensis failed to influence the course of N . dubius infections or the status of the selected mice as R, Rd and L to infection with N . dubius . R and L mice were equally susceptible to Mesocestoides corti infection but more resistant than Rd mice . R and L mice died sooner after infection with Salmonella typhimurium than Rd, although R survived longer than L mice.

Toxicon, 1983, 21(6), 785 - 96
Cytotonic enterotoxins and cytotoxic factors produced by Salmonella enteritidis and Salmonella typhimurium; Baloda SB et al.; Strains of Salmonella enteritidis and Salmonella typhimurium isolated from human diarrheal cases produced heat-labile enterotoxin(s) and cytotoxic factor(s) which elongated, lysed or deformed Chinese hamster ovary cells in tissue culture . The toxin(s) caused fluid accumulation in ligated rabbit gut loops and produced increased skin permeability . Salmonella toxin produced by these strains does not cross-react immunologically with high titer Vibrio cholerae toxin antisera or heat-labile Escherichia coli enterotoxin antisera used in this study and does not bind to galactose--Sepharose gel . The activity of the toxin was not inhibited by GM1-ganglioside.

Dev Comp Immunol, 1983 Summer, 7(3), 555 - 62
Bacteria-immune system interactions . XII . Effects of aging on Balb/c mice responsiveness to Salmonella typhimurium; Kleinman R et al.; Age-associated changes in reactivity to bacteria were tested at several levels . At the level of bacteria binding to lymphocytes, there were no significant differences between young and old mice, however the lymphocytes from adults bound less bacteria than the other age groups . Similarly, the lymphocytes from spleens of adult mice were less efficient in killing bacteria than all the other age groups . The lymphocytes of young mice had higher and longer range reactivity than the ones from old mice . Bacterial stimulation did not produce significant levels of thymidine incorporation in any of the age groups tested.

Nutr Cancer, 1983, 5(1), 26 - 33
Genotoxicity of brown-colored polymerization products formed in smoke flavors; Pool BL et al.; Smoke aroma essences, which are prepared from smokehouse smoke by condensation and purification, are used for flavoring raw food products . The essences spontaneous decompose and produce brown-colored polymerization products, which may react with protein and be liberated within the acidic environment of the human stomach . The potential of these products to cause DNA damage was studied in two microbial and two in vivo assay systems . The polymerization products induced his+ reversion in Salmonella typhimurium TA 100 after metabolic activation by liver enzymes . There was no significant activity in a differential killing assay with repair-deficient strains of Escherichia coli WP2 . In vivo tests demonstrated significant increases in the rate of sister chromatid exchanges in bone marrow cells of Chinese hamsters, but no increase in micronuclei was detectable . Thus, genotoxic components may be present in the brown-colored fractions of smoke aroma essences, but further study is needed.

Environ Mutagen, 1983, 5(5), 687 - 94
Mutagenicity testing of two tropical plant materials with pesticidal potential in Salmonella typhimurium: Phytolacca dodecandra berries and oil from seeds of Azadirachta indica; Jongen WM et al.; In this study the mutagenic potential of two tropical plant materials was investigated in Salmonella typhimurium strains TA98 and TA100 . The oil extract from seeds of Azadirachta indica showed no mutagenic activity in either strain with or without addition of metabolizing systems . When extracts of Phytolacca dodecandra berries were tested, only the butanol extract caused direct mutagenicity in TA98 . After addition of rat liver homogenate, again only the butanol extract was positive in TA98 . Addition of gut flora extract as metabolizing system generated positive effects in both the methanol extract and the butanol extract . The water extract showed only a slight positive effect, which can most probably be ascribed to the presence of histidine in the sample.

Ann N Y Acad Sci, 1983, 407, 258 - 66
Cell-mediated mutagenesis of Chinese hamster V79 cells and Salmonella typhimurium; Langenbach R et al.; In the cell-mediated approach, intact cells metabolically activate the chemical and the genetic end points are measured in cocultivated or coincubated target cells . Cell-mediated systems have been used to study fundamental problems in carcinogenesis, such as organ and species specificity of carcinogen activation, and in screening for carcinogenic chemicals . In the studies discussed here, cells from various rat, hamster, or bovine tissues are used to metabolically activate the chemical, and mutation and/or SCE induction in V79 cells and mutation of S . typhimurium are measured as genetic end points . The detection of genetic activity of a chemical depends both on the cell (organ, species, type, etc.) used for metabolic activation and on the genetic end point measured . Hydrocarbons and nitrosamines are two classes of environmentally significant chemicals that are sensitively detected with cell-mediated systems . The cell-mediated approach provides a valuable metabolic activation component for short-term in vitro systems, and further studies are needed to utilize and evaluate its full potential.

Ann N Y Acad Sci, 1983, 407, 164 - 76
Mutagenicity and carcinogenicity correlations between bacteria and rodents; Brusick D; Detection of mutation in bacteria has acquired the status of an accepted procedure in genetic toxicology programs . The methods presently employed in such programs include both forward and reverse mutation-induction techniques in strains of Salmonella typhimurium and Escherichia coli . The specific strains used in these techniques have been selected over the years on the basis of their sensitivity to a broad range of chemical mutagens . In addition, it has been reported that chemical carcinogens can be presumptively identified on the basis of these assays, and bacterial testing has been generally considered the front-line test procedure for the identification of presumptive mutagenic carcinogens . An analysis of correlative studies both retrospective and cross-sectional shows a range of predictive capabilities depending on features such as chemical class, carcinogenic mechanism, and requirements for specific metabolic toxification processes . The greatest limitations associated with the use of bacteria mutation testing is the real and/or perceived issue of the test or a misinterpretation of the correlation coefficients under conditions of routine application . Concerns related to the performance (reliability, reproducibility, and predictability) and relevance of bacteria assays perpetuate controversy surrounding their application to hazard assessment . A review of several studies comparing mutation induction and tumor induction indicates that the Ames test can be useful in screening large numbers of chemicals, but the true correlation coefficient is only about 80% when compared to tumor responses in mice and rats.

Mol Cell Biochem, 1983, 52(2), 97 - 106
Isolation and characterization of a tRNA(guanine-7-)-methyltransferase from Salmonella typhimurium; Colonna A et al.; The tRNA modifying enzyme, S-adenosylmethionine:tRNA(guanine-7-)-methyltransferase, has been extensively purified from Salmonella typhimurium . A rapid and efficient purification method using phosphocellulose chromatography followed by ammonium sulfate precipitation and Sephadex G-100 gel filtration is described . The enzyme appears to be a single polypeptide chain with a molecular weight of approximately 25 000--30 000 daltons . The Km for S-adenosylmethionine and for undermethylated tRNA is 53 microM and 3.4 microM, respectively . The methylation reaction is dependent on added monovalent or divalent cations; 5 mM spermidine, 3 mM MgCl2 and 1 mM spermine are the most effective . The enzyme, though not homogeneous, is free from contaminating ribonucleases and other tRNA methyltransferases.

Mol Gen Genet, 1983, 190(3), 427 - 31
P22 antirepressor protein prevents in vivo recA-dependent proteolysis of P22 repressor; Prell HH et al.; A method was developed to demonstrate recA-dependent P22-repressor breakdown in vivo by SDS-polyacrylamide electrophoresis of unfractionated extracts of phage-infected, lysogenic Salmonella typhimurium strains TA1530 rec+ and TA1530 recA1- . The antirepressor of P22 is not cleaved by recA protein . Under conditions of unregulated ant-overproduction (Harvey et al . 1981) antirepressor protects c2-repressor in vivo against proteolytic cleavage by recA protein.

Mol Gen Genet, 1983, 190(2), 183 - 8
Genetic instability associated with the aroC321 allele in Salmonella typhimurium involves genetic duplication; Hoffman GR et al.; Strains of Salmonella typhimurium that contain the aroC321 allele require phenylalanine, tyrosine, and tryptophan for growth but revert to tryptophan-prototrophy at high frequencies (about 10(-4) per cell plated) . The Trp+ derivatives remain auxotrophic for phenylalanine and tyrosine and are genetically unstable, in that they readily give rise to cells that require all three aromatic amino acids . On the basis of growth characteristics and genetic instability, it has been proposed that reversion to tryptophan-prototrophy in aroC321 strains occurs by genetic duplication . This paper provides genetic evidence in support of that hypothesis . The data indicate, moreover, that the tryptophan prototrophs contain a duplication that extends at least from glpT to xyl, a region of greater than 30% of the Salmonella chromosome . The aroC locus is found within the duplicated region, and aroC321/aroC321 merodiploids apparently grow as tryptophan prototrophs because of a gene-dosage effect.

Environ Mutagen, 1983, 5(4), 577 - 88
Evaluation of the release of mutagens and 1-nitropyrene from diesel particles in the presence of lung macrophages in culture; King LC et al.; The release and recovery of mutagenic activity and 1-nitropyrene from diesel particles phagocytized and cultured with lung macrophages were studied . The Ames Salmonella typhimurium plate incorporation assay was used to measure mutagenic activity . Quantitative analysis of 1-nitropyrene was performed with liquid chromatography/fluorescence analysis . The cytotoxicity and phagocytosis of diesel particles with and without fetal calf serum were evaluated to select exposure concentrations that resulted in minimal toxicity and maximal engulfment of particles by the macrophages . The diesel-particle exposure concentrations for the mutagenicity studies were 200 micrograms/ml in the absence of serum and 375 micrograms/ml in the presence of serum . Engulfment and incubation of diesel particles with lung macrophages resulted in the loss of considerable mutagenic activity (97-98%) and significantly less 1-nitropyrene (10-25%) . These studies suggest that lung macrophages have the capability to metabolize mutagenic nitroaromatics found in diesel particles.

Environ Mutagen, 1983, 5(4), 565 - 75
Effect of bacterial concentration on reversions induced in Salmonella typhimurium TA1538 by N-hydroxy-2-acetylaminofluorene; White GL et al.; Reversions induced by N-hydroxy-2-acetylaminofluorene (N-OH-AAF) were measured in the Salmonella/microsome quantitative plate assay using various concentrations of Salmonella typhimurium strain TA1538 . The number of induced revertants increased with an increasing number of bacteria/plate, but the variation in reversion frequency was not as great as the variation in bacterial concentration . The effects of bacterial concentration on reversion fixation, phenotypic expression, selection of his+ revertants, and the interaction of the mutagen with bacterial DNA were examined . Suspension cultures of TA1538 were exposed to N-OH-AAF and various dilutions were prepared and assayed for revertants/10(8) bacteria . Reversion frequencies were very dependent on bacterial concentration between approximately 0.2 X 10(8) and 2 X 10(8) bacteria/plate . Revertants/10(8) TA1538 were reduced above about 2 X 10(8) bacteria/plate, indicating that culture conditions limited reversion fixation, expression and/or selection at these concentrations . The number of spontaneous revertants/plate determined both from bacteria exposed to dimethyl sulfoxide in suspension culture and in the Salmonella/microsome assay were not greatly affected by bacterial concentration . To study the effect of bacterial concentration on the interaction of the mutagen with bacterial DNA, various concentrations of TA1538 were exposed to the same dose of N-OH-AAF . Both revertants/10(8) TA1538 and DNA adducts varied inversely with bacterial concentration . The effect of bacterial concentration on both reversion fixation and/or expression and on mutagen binding to DNA may influence reversion frequencies in the Salmonella/microsome assay.

Environ Mutagen, 1983, 5(4), 527 - 40
Mutagenicity evaluation of amino-oxazoline derivatives using in vitro and in vivo short-term tests; Suter W et al.; During routine investigation of potential drugs it was found that 1-methyl-4-(2-oxazoline-2-ylamino)-indazole (1) compound 1 was mutagenic for Salmonella typhimurium TA1535 and TA100 . The genotoxicity of compound 1 was confirmed by the following in vitro test systems: V79 Chinese hamster cells (HGPRT-locus), Saccharomyces cerevisiae D7 (mitotic gene conversion, mutations, aberrations), and Escherichia coli (rec-assay) . On the other hand, when compound 1 was tested in vivo (micronucleus test in mice and sister chromatid exchange in Chinese hamsters) it did not show evidence of genotoxic activity . In order to study structure/activity relationships, different analogues of compound 1 were tested in Salmonella typhimurium TA1535 . The tests showed that (1) most 2-amino-oxazolines were mutagenic for the test organism; (2) the 2-amino-imidazoline and 2-amino-thiazolidine derivatives tested were not mutagenic; (3) substituents bound to the extranuclear nitrogen of the 2-aminooxazoline ring had only a weak influence on the mutagenic potential; and (4) methylation of the oxazoline ring, most conspicuously at the carbon in position 5, strongly reduced the mutagenic effect . From these observations it is concluded that the reaction of nucleophilic DNA sites with the most electrophilic site of the oxazoline ring, ie, the carbon in position 5, is responsible for the genotoxicity of amino-oxazoline compounds . Due to the genotoxicity observed in these in vitro tests this class of compounds was no longer developed, but dropped, even without performing a long-term carcinogenicity study or considering the negative in vivo findings.

Arzneimittelforschung, 1983, 33(3), 369 - 72
Mutagenicity studies on tibezonium, a new oropharyngeal disinfectant; Veronese M et al.; N,N-Diethyl-N-methyl-{2-{{4-(4-phenylthio) phenyl}-3H-1,5-benzodiazepin-2-yl}thio}-ethanaminium iodide) (tibezonium iodide; CAS-54663-47-7), a new oropharyngeal disinfectant, was tested, using the Ames procedure with and without metabolic activation, on five strains of Salmonella typhimurium and using the host mediated assay with Schizosaccharomyces pombe as microorganism test . In both tests the drug did not show any mutagenic activity when compared with mutagenic standards.

Adv Exp Med Biol, 1983, 162, 297 - 302
Strain dependent variation of delayed-type hypersensitivity in Salmonella typhimurium infected mice; Killar L et al.; Inherently hypersusceptible C3H/HeJ and C3HeB/FeJ mice show increased resistance to challenge with virulent S . typhimurium after immunization with a live, avirulent S . typhimurium mutant in the absence of a delayed-type hypersensitivity response, while innately resistant C3H/HeNCr1BR and CD-1 mice show both immunity and positive footpad reactions after immunization . Understanding the mechanism for this specific anergy in the hypersusceptible strains may provide clues for understanding the immune defect that causes these mice to be so exquisitely susceptible to Salmonella infection.

Microbiol Immunol, 1983, 27(2), 167 - 75
Delayed hypersensitivity in murine salmonellosis: specificity of footpad reaction in mice infected with rough mutants of Salmonella typhimurium; Cho N et al.; Delayed type (footpad) hypersensitivity (DTH) in BALB/c mice immunized with rough mutant strains of Salmonella typhimurium LT2 was examined . Injection of live organisms of an Rb mutant TV148 strain induced DTH in mice, while injection of the heat-killed organisms did not . The mice immunized with live organisms of the Ra, Rb, Rc, Rd, and Re mutant strains showed positive footpad reactions to the heat-killed cell antigen of LT2 (wild type) strain . The mice immunized with the Rb mutant strain also showed positive footpad swellings in response to heat-killed cell antigens of S . paratyphi A, S . paratyphi B, S . typhi, S . enteritidis, and S . cholerae-suis . Furthermore, positive reactions to antigens of Escherichia coli and Shigella flexneri were seen in the TV148-immunized mice, but the mice did not respond to heat-killed organisms of Pseudomonas aeruginosa or Staphylococcus aureus . The cross-reactive footpad reaction to E . coli could be transferred adoptively with T cells prepared from the spleens of TV148-immunized mice into syngeneic recipients . These results suggest that the cross-reactive DTH antigen(s) is widely distributed among related organisms such as Shigella and Escherichia.

Microbiol Immunol, 1983, 27(2), 117 - 30
Immunogenic dialyzable factor derived from a ribosomal fraction of Salmonella typhimurium . II . Isolation and characterization of the protective moiety in the dialyzable factor; Kita E et al.; An immunogenic dialyzable factor was obtained by dialysis of the freeze-thawed ribosomal fraction derived from a smooth virulent strain (LT2) of Salmonella typhimurium . Ion exchange chromatography of the dialyzable factor on Dowex 1-X2 (Cl- form) demonstrated the presence of four peaks and the fourth peak eluted with 0.4 M NaCl in 0.005 N HCl was found to be necessary for protection . This effective peak was not obtained by chromatography of nonprotective dialyzable factors such as an RNase digest . Dowex chromatography of the dialyzable factors isolated from rough mutants of strain LT2 revealed that the dialyzable factor of strain SL1004 whose live vaccine is capable of inducing protective immunity contained fairly large amounts of peak IV . DEAE-cellulose for two-dimensional thin layer chromatography was used to identify the composition of the dialyzable factor and peak IV . Eight spots were located under ultraviolet light and seven spots were characterized by their absorption ratios . In peak IV, four nucleotides were located and identified by comparison with a map of the original dialyzable factor . The data show that the effective components of the dialyzable factor are mixed nucleotides and may be unique to ribonucleic acids of strains of S . typhimurium in which live vaccines are capable of affording mouse protection.

Microbiol Immunol, 1983, 27(1), 7 - 24
Immunogenic dialyzable factor derived from a ribosomal fraction of Salmonella typhimurium . I . Preparation of the protective dialyzable factor from the ribosomal fraction by the freeze-thaw procedure; Kita E et al.; The preparation, properties, and immunogenicity of the dialyzable factor from a ribosomal fraction of Salmonella typhimurium are described . The ribosomal fraction was purified to eliminate O-antigenic components, by affinity chromatography (Sepharose-anti-O antibody conjugates used as immunoadsorbent) . The dialyzable factor was obtained in the concentrated dialysate of the purified ribosomal fraction which was alternately frozen in dry-ice acetone and thawed in an 80 C water bath, for a total of five or six cycles . When this preparation was tested for its ability to protect mice against challenge with 1,000 LD50 of the homologous bacteria, it afforded 100% protection at a dose equivalent to 5.0 micrograms of RNA . The protection conferred by this factor was mainly cell mediated but immune serum enhanced this immunity despite the fact that no antibodies were detected in it . The protective activity of this factor was sensitive to RNase digestion but resistant to proteolytic enzymes . Ion exchange chromatography of this factor with DEAE-Sephadex A-25 (in 7 M Urea-0.02 M Tris-HCl buffer, pH 7.5) resulted in a single A260 peak which was found to be immunogenic . Chemical analysis of this peak after it was concentrated and desalted revealed that this immunogenic fraction was composed mainly of mixed nucleotides . The data indicate that protective immunity conferred by a ribosomal vaccine is associated with RNA but may not require the intact RNA molecule.

Mol Gen Genet, 1983, 189(3), 458 - 62
Control of arg gene expression in Salmonella typhimurium by the arginine repressor from Escherichia coli K-12; Gardner MM et al.; The regulation of synthesis of arg enzymes in Salmonella typhimurium by the arginine repressor of Escherichia coli K-12 has been reevaluated using a strain of S . typhimurium in which the argR gene was rendered nonfunctional by inserting the translocatable tetracycline-resistance element Tn10 into the argR gene . In contrast to previous studies, the introduction of the argR+ allelle of E . coli on an F-prime factor to the argR::Tn10 S . typhimurium strain reduced the synthesis of arg enzymes to essentially wild-type levels . The elevated levels of arg enzymes observed in other hybrid merodiploids may have been the consequence of the formation of hybrid repressor molecules . The readily scoreable phenotype of tetracycline resistance facilitated establishing linkage of cod and argR (0.6% cotransduction) by P22 phage-mediated transduction.

Environ Mutagen, 1983, 5(2), 193 - 215
Mutagenic evaluations of four rubber accelerators in a battery of in vitro mutagenic assays; Hinderer RK et al.; The mutagenic/carcinogenic potential of four commercial accelerators were evaluated using a battery of in vitro assays . All of these compounds were mutagenic in one or more assays . Positive responses were noted in the Escherichia coli pol A+/pol A- DNA repair, mouse lymphoma L5178Y TK+/- forward mutation, BALB/3T3 cell transformation, and CHO cell chromosome aberration assays . In contrast to previous studies of accelerators, no mutagenic response was observed in the E coli WP2 uvrA- assay or in any of the Salmonella typhimurium strains tested . These studies have indicated that rubber accelerators should be regarded as potential human health hazards and that further in vitro and in vivo studies are needed to assess the potential genetic hazards of this large class of chemicals.

Drug Chem Toxicol, 1983, 6(1), 71 - 82
Mutagenesis of nitro-dibenzo-p-dioxins; White WE Jr et al.; Two dioxins, 2-nitro-dibenzo-p-dioxin (I) and 2,3 dichloro-7-nitro-dibenzo-p-dioxin (II), were prepared by condensing 3,4 dichloro nitrobenzene with the dipotassium salts of catechol and 4,5-dichloro-catechol, respectively . Both compounds were very mutagenic for Salmonella typhimurium TA1538, but only weakly mutagenic for TA1537 . Compound II, but not compound I, also induced a few (approximately 100 revertants at near toxic doses) point mutations in strain TA1535.

Carcinogenesis, 1983, 4(6), 787 - 9
Synthesis of 1,6-diaminopyrene from 1,6-dinitropyrene and its S9 dependent mutagenicity to S . typhimurium; Ashby J et al.; 1,6-Dinitropyrene elicits a potent mutagenic response in a range of microorganisms in the absence of auxiliary metabolism (S9 mix) . This activity is considered to be dependent upon nitroreductase enzymes endogenous to the marker organism producing electrophilic species from one or both of the nitro groups . In order to evaluate this suggestion 1,6-diaminopyrene has been synthesised, characterized and found to elicit a mutagenic response in strain TA98 of Salmonella typhimurium, but only when evaluated in the presence of S9 mix . The active dose-range of the diamino compound was 10(4) times higher than that of the parent dinitro compound.

Microbios, 1983, 36(144), 71 - 84
The influence of growth in the presence of antibiotics on the lipid composition of Salmonella typhimurium; El-Khani MA et al.; The lipid content of Salmonella typhimurium was examined after growth in the presence of benzylpenicillin, ampicillin, mecillinam and tetracycline in nutrient broth and a defined medium with either glucose, acetate or glycerol as the sole carbon source . The total lipid content was not changed significantly but the level of palmitoleic acid was higher in antibiotic treated cells with the level of C17 delta being lower . The level of phospholipids was increased slightly in antibiotic treated cells, with phosphatidylserine and diphosphatidyl glycerol being the most affected . The results are discussed in terms of antibiotic resistance and mode of action of the beta-lactam antibiotics.

Environ Mutagen, 1983, 5(3), 263 - 72
Comparative mutagenicity of a coal combustion fly ash extract in Salmonella typhimurium and Chinese hamster ovary cells; Li AP et al.; The dichloromethane extract of a coal combustion fly ash sample obtained from an experimental fluidized bed coal combustor was tested for mutagenicity in Salmonella typhimurium and cultured Chinese hamster ovary (CHO) cells . The extract was directly mutagenic in S typhimurium strain TA98 and the nitroreductase deficient strains TA98NR and TA98/1,8DNP6 . The mutagenicity observed in TA98NR and TA98/1,8DNP6 was lower than that in TA98 . Addition of exogenous Aroclor 1254-induced rat liver supernatant (liver S9) decreased the bacterial mutagenicity of the extract . A different mutagenic response was observed in CHO cells . In the absence of liver S9, although the extract was cytotoxic to CHO cells, no significant mutagenicity was observed . Addition of exogenous liver S9 decreased the cytotoxicity and increased the mutagenicity at both Na+-K+-ATPase and hypoxanthine-guanine phosphoribosyl transferase (HGPRT) gene loci in CHO cells . Using gas chromatography/mass spectrometry (GC/MS) and tandem quadruple mass spectrometry, a number of polynuclear aromatic hydrocarbons (PAHs) and nitrated PAHs (nitro-PAHs) were tentatively identified and quantitated . A possible explanation of the difference in bacterial and mammalian mutagenicity of the extract is that the bacterial mutagenicity was induced by the nitro-PAHs that are potent bacterial mutagens and mammalian mutagenicity was induced by both PAHs and nitro-PAHs that are promutagens.

Genetics, 1983 Jan, 103(1), 23 - 9
New suppressors of frameshift mutations in Salmonella typhimurium; Kohno T et al.; Several new types of suppressor mutants have been isolated . These were identified among revertants of mutants originally generated by mutagens other than the acridine-derived ICR191 . The new suppressors correct mutations other than those with runs of C or G which are recognized by the previously described suppressors . Several frameshift mutations are corrected by more than one suppressor type . Apparently, the DNA base sequence near these mutant sites includes sites of action for several distinct suppressor types.

Carcinogenesis, 1983, 4(4), 409 - 13
Genetic and cytogenetic effects of 1,3-dimethyl-3-phenyl-1-nitrosourea in Salmonella typhimurium and Chinese hamster V79 cells; Thust R et al.; 1,3-Dimethyl-3-phenyl-1-nitrosourea (DMPNU) shows no spontaneous decomposition in aqueous buffered solution (pH 7.0) at 37 degrees C over a measuring period of 10 days, but it is directly genotoxic in all assays applied . This compound induces base substitutions in Salmonella typhimurium (especially in the plasmid harbouring strain TA 100), gene mutations at the HGPRT+ locus of Chinese hamster V79 cells, and is a very potent inducer of clastogenic damage and sister chromatid exchanges in V79 cells . Data on gene mutation induction by 1-methyl-1-nitrosourea are included for comparison . The findings on DMPNU are discussed in comparison with trialkylnitrosoureas . In contrast to these latter compounds, DMPNU is active without addition of S9 mix in vitro . It is assumed that its genotoxic activity is due to an intracellular catalytic degradation favoured by the electron-withdrawing effect of the phenyl group.

Res Vet Sci, 1983 Jan, 34(1), 16 - 20
Experimental study of some factors limiting 'competitive exclusion' of salmonella in chickens; Lafont JP et al.; Some factors affecting the efficiency of competitive exclusion of Salmonella typhimurium var copenhagen in chicks were studied experimentally under gnotobiotic conditions . Axenic chickens were given dilute suspensions of adult faeces and exposed to the salmonellae . Prevention of colonisation of the gut by salmonellae ('competitive exclusion') was variable and depended possibly in part on the source of the adult faeces used to protect the chicks . Exclusion was also dose-dependent, a large inoculum of the salmonellae (10(7) viable organisms per animal) leading to colonisation in treated chicks . An inapparent carrier state was sometimes produced by lower doses of the salmonellae (10(2) viable organisms per animal), but bursts of excretion still appeared after inoculation of the salmonellae . In inapparent healthy carriers, the inoculation of a dose of Eimeria tenella oocysts that was known to produce subclinical caecal coccidiosis led to the shedding of large numbers of salmonellae for over two weeks, and the use of 'competitive exclusion' in poultry as a preventive measure for salmonella infections might thus be limited by the frequent occurrence of subclinical coccidiosis in the field.

Environ Mutagen, 1983, 5(1), 9 - 15
Isolation of streptomycin-dependent strains from salmonella typhimurium TA98 and TA100 and their use in mutagenicity tests; Kada T et al.; Streptomycin-dependent (SMd) mutant strains of Salmonella typhimurium TA98 and TA100 were isolated . A highly sensitive detection system was obtained by using these SMd derivatives for the SMd leads to SMind mutation . The system was available for testing the mutagenicities of samples containing histidine, such as food.

Environ Mutagen, 1983, 5(1), 87 - 100
Some findings on mutagenicity in airborne particulate pollutants; Tokiwa H et al.; Mutagenic activity in particulate airborne pollutants in several samples collected in a wide variety of industrial, residential, and small-scale factory districts over the past seven years was detected by the Ames test . The particulate air samples that were not contaminated with several chemicals such as NO (less than 0.001 ppm), NO2 (less than 0.001 ppm), and SO2 (less than 0.001 ppm) showed only low mutagenic activity (1 revertant/m3) when they were tested with Salmonella typhimurium strain TA98 in the presence of S9 mix . However, most of the samples polluted by particulate matters showed high mutagenicity, with responses varying from 2.4 to 445 revertants per m3: 67 samples from an industrial area induced an average of 44 revertants per m3; 60 from a residential area, 16.2; and 10 from a small-scale factory area, 72.1 . For assessing the mutagenic potential of the pollution in the atmosphere, the frequency of mutation determined with strain TA98 in the presence of S9 mix was used to divide the samples tentatively into five groups (A-E) on the basis of the normal logarithmic distribution curve of 137 samples . Air samples belonging to group A gave less than 2.3 revertants per m3 of air (1.12 +/- 0.12, no pollution); those of group B gave a range of 2.4 to 8.6 (5.93 +/- 1.91, slight pollution); those of group C gave a range of 8.7 to 30.2 (16.0 +/- 5.36, moderate pollution); those of group D gave a range of 30.3 to 115 (56.7 +/- 20.1, considerable pollution); and those of group E gave more than 116 (234 +/- 119, heavy pollution) . Of the 137 samples tested, 6 samples (4.4%) were assigned to group A, 38 (27.7%) to group B, 52 (38.0%) to group C, 34 (24.8%) to group D, and 7 (5.1%) to group E . Furthermore, the samples in an industrial area were classified in the order of group C (35.8%), group B (26.9%), group D (22.4%), group E (8.96%), and group A (5.97%), and those in a residential area in the order of group C (46.7%), group B (33.3%), group D (18.3%), and group A (1.67%).

Environ Mutagen, 1983, 5(1), 17 - 22
5-Nitroacenaphthene: a newly recognized role for the nitro function in mutagenicity; McCoy EC et al.; The direct-acting mutagenicity of 5-nitroacenaphthene for Salmonella typhimurium is dependent upon the reduction of the nitro function as evidenced by the significant decrease in mutagenicity seen with nitroreductase-deficient Salmonella strains . Addition of microsomal preparations results in a significant increase in mutagenicity and a by-passing of the block in nitroreductase-deficient and arylhydroxylamine esterifying-deficient enzyme strains . The results are taken to indicate that the microsome-induced mutagenicity is due primarily to oxidation of the acenaphthene moiety . The results are consistent with recent studies which indicate that the nitro function exercises a directing effect on ring oxidation.

Carcinogenesis, 1983, 4(3), 331 - 3
Unequivocal demonstration that malondialdehyde is a mutagen; Basu AK et al.; Malondialdehyde (MDA), a product of lipid peroxidation and prostaglandin biosynthesis, has been reported to be mutagenic and carcinogenic . Recent evidence suggests, however, that strongly mutagenic impurities are generated during the preparation of MDA that may contribute to the observed biological activity . Since MDA is widely produced in animal tissue it is important to establish whether it is actually mutagenic and carcinogenic . We have utilized three complementary methods for the preparation of highly purified MDA for biological testing . These are chromatographic purification of the sodium salt of MDA, sublimation of the free acid of MDA, and basic hydrolysis of beta-(p-nitrophenoxy)acrolein . The latter is a unique method that we have developed specifically to generate MDA under non-acidic conditions where it is stable . MDA prepared by each method induced approximately 5 revertants/mumol in Salmonella typhimurium his D 3052 . This unequivocally demonstrates that MDA is a weak mutagen.

Carcinogenesis, 1983, 4(3), 305 - 10
Effects of alpha-deuterium substitution on the mutagenicity of 4-(methyl-nitrosamino)-1-(3-pyridyl)-1-butanone (NNK); Hecht SS et al.; 4-(Methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), a carcinogenic tobacco specific nitrosamine, can be converted to electrophilic diazohydroxide intermediates by metabolic hydroxylation of either the methylene carbon (carbon 4) or the methyl carbon attached to the nitrosamine group . To investigate the relative importance of these two processes in NNK mutagenesis, we synthesized 4,4-dideutero-4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone({4,4,-D2}NNK) and 4-(trideuteromethylnitrosamino)-1-(3-pyridyl)-1-butanone ({CD3} NNK), and evaluated their mutagenic activities in Salmonella typhimurium tester strains . In the presence of Aroclor induced rat liver 9000 g supernatant, NNK and {4,4-D2}NNK had comparable mutagenic activities towards S . typhimurium TA 1535 and TA 100, but {CD3}NNK was inactive in both strains . These results suggest that hydroxylation of the methyl group of NNK is more important than hydroxylation of carbon 4 in its activation to a mutagen . To test the inherent mutagenicity of 4-oxo-4-(3-pyridyl)butyldiazohydroxide and methyldiazohydroxide which would be formed by methyl hydroxylation or carbon 4 hydroxylation, respectively, we compared the mutagenicities, without activation, of the corresponding model compounds, 4-(carbethoxynitrosamino)-1-(3-pyridyl)-1-butanone and carbethoxynitrosaminomethane (methylnitrosourethane) . Both compounds were highly mutagenic toward S . typhimurium TA 1535 and TA 100, but at doses of 4 x 10(-3) to 4 x 10(-4) mumol/plate, only 4-(carbethoxynitrosamino)-1-(3-pyridyl)-1-butanone was mutagenic . These results are consistent with those obtained with the deuterium substituted compounds and indicate the importance of 4-oxo-4-(3-pyridyl)butylation of DNA in NNK mutagenesis.

Carcinogenesis, 1983, 4(3), 291 - 5
The morphological transformation of Syrian hamster embryo cells by chemicals reportedly nonmutagenic to Salmonella typhimurium; Amacher DE et al.; Nine chemicals classified as presumptive carcinogens on the basis of chronic rodent bioassays and one suspected human carcinogen which are reportedly not mutagenic to Salmonella typhimurium tester strains were tested for the ability to produce morphological transformation in Syrian hamster embryo cells in the absence of any exogenous source of metabolic activation . Acetamide, benzene, carbon tetrachloride, L-ethionine, monuron, piperonyl butoxide and trichloroethylene all induced positive morphological transformation in the presence of at least one of two medium and serum combinations as did the positive controls, ethyl methanesulfonate and benzo{a}pyrene . The remaining three chemicals, griseofulvin, isoniazid and trypan blue, did not induce morphological transformation under these same test conditions suggesting that they differ from the other seven chemicals in mechanism of action, target specificity or species susceptibility . Our results for seven of those ten selected chemicals in the clonal transformation assay using Syrian hamster embryo cells differ from their reported activity in the S . typhimurium point mutation assay . On the basis of this small sample, the Syrian hamster embryo transformation assay was a better predictor of the reported rodent bioassay results.

Environ Health Perspect, 1983 Jan, 47, 171 - 6
Biological actions of nitroarenes in short-term tests on Salmonella, cultured mammalian cells and cultured human tracheal tissues: possible basis for regulatory control; Sugimura T et al.; Pure synthetic nitropyrene compounds were subjected to a mutation test using Salmonella typhimurium TA 98 and TA 100 with and without S9 mix, a metabolic activation system . Dinitropyrenes were highly mutagenic . Among them, 1,8-dinitropyrene was the most potent mutagen, producing 940,000 revertants of TA 98/micrograms . 1,3,6-Trinitropyrene and 1,3,6,8-tetranitropyrene were also highly mutagenic, producing 708,000 and 221,000 revertants/micrograms, respectively . 1-Nitropyrene was weakly mutagenic . All nitropyrenes were more mutagenic towards TA 98 than TA 100, and all mutagenic activities were abolished by the presence of S9 mix . Di- and trinitropyrenes were demonstrated to be mutagenic to Chinese hamster lung cells without metabolic activation, by using diphtheria toxin resistancy as a marker . The range of mutagenic potential of nitropyrenes was much narrower with cultured mammalian cells than with Salmonella . 1-Nitropyrene was not mutagenic . 1,6-Dinitropyrene and 1-nitropyrene induced unscheduled DNA synthesis in epithelial cells of in vitro cultured human bronchi, as did diol-epoxides of benzo{a}pyrene, while benzo{a}pyrene itself was inert . 1-Nitropyrene and 3-nitrofluoranthene produced subcutaneous fibrosarcomas at the loci of injections in the backs of rats . Tumors were found in 47% and 40% of animals with total doses of 40 mg of 1-nitropyrene and 30 mg of 3-nitrofluoranthene, respectively . The biomedical significance of nitroarenes is discussed.

Carcinogenesis, 1983, 4(2), 161 - 7
Mutagenicity and DNA damage induced by arylamines in the Salmonella/hepatocyte system; Staiano N et al.; Coincubation of isolated, intact rat hepatocytes with Salmonella typhimurium tester strain TA 98 (Salmonella/hepatocyte system) has been employed to determine both bacterial mutagenicity and DNA damage in rat hepatocytes following treatment with 2-acetylaminofluorene (AAF) and its derivatives . In vivo pretreatment of rats with either 2,3,7,8-tetrachlorodibenzodioxin or 3-methylcholanthrene markedly increased both DNA damage and bacterial mutation frequency upon incubation of AAF or 2-aminofluorene (AF) in this system . The increase in damage to the hepatocyte DNA was more pronounced after AAF treatment than following AF exposure, while the increase in bacterial mutation frequency was greater after AF treatment . Treatment of hepatocytes with paraoxon prior to exposure to N-hydroxy-2-acetylaminofluorene (N-OH-AAF) or N-acetoxy-2-acetylaminofluorene (N-OAc-AAF) partially inhibited both DNA damage and the bacterial mutagenicity caused by these agents . Treatment of primary rat hepatocytes with 2-hydroxy-2-aminofluorene (N-OH-AF) causes a low level of DNA breaks . Substitution of primary rat hepatocytes with highly differentiated rat hepatoma cells (Reuber H4-II-E) revealed a low level of DNA breakage after exposure to N-OH-AAF whereas treatment with either N-OAc-AAF or N-OH-AF induced a dose dependent increase in DNA breaks . Pretreatment of the Reuber cells with paraoxon inhibited the DNA damage caused by N-OAc-AAF whereas the DNA damage induced by N-OH-AF was increased after paraoxon treatment . Employing host cells with differing metabolic capacity, such as Reuber vs . primary hepatocytes, in the Salmonella/hepatocyte system, may allow a determination of the relative importance of different metabolic pathways in mutagenicity and/or genotoxicity of arylamines.

Am J Vet Res, 1983 Jan, 44(1), 46 - 50
Effects of transportation, surgery, and antibiotic therapy in ponies infected with Salmonella; Owen RA et al.; Seventeen ponies were infected with Salmonella typhimurium and then 15 were variously stressed by transportation and/or surgery and 9 were given oxytetracycline . Indications of Salmonella reactivation occurred in all the stressed ponies . Diarrhea due to a reactivation of the Salmonella infection did not develop until greater than 3 days after stress, although maximal shedding of organisms occurred within 24 hours . A neutropenia generally occurred within 24 hours after stress and lasted about 5 days . A rectal temperature greater than 39 C usually did not occur . An increase in serologic titer was noticed in about half of the ponies . Transportation had a major role in reactivating the Salmonella infection, and 1 pony died of peracute colitis . The use of oxytetracycline prolonged the excretion of Salmonella; therefore, this drug should not be used after stress, particularly transportation, in ponies that have diarrhea or are known to be Salmonella carriers.

Mutat Res, 1983 Jan, 119(1), 7 - 14
A comparison of the mutagenicity and macromolecular binding of the carcinogens Michler's ketone and reduced Michler's ketone; McCarthy DJ et al.; The mutagenicity of 4,4'-bis(dimethylamino)benzophenone (Michler's ketone, MK, CAS No . 90-94-8) and 4,4'-methylenebis(N,N-dimethyl)benzamine (reduced Michler's ketone, RMK, CAS No . 101-61-1) for Salmonella typhimurium strain TA100 was compared using activated 9000 X g (S9) liver supernatants from 2 animal species . RMK, but not MK, was mutagenic when incubated with phenobarbital-induced B6D2F1 mouse or Osborne-Mendel rat-liver S9 . The mutagenic response for RMK was linear at doses from 1 to 33 micrograms/plate . A higher percentage of RMK and MK became irreversibly bound to mouse-liver macromolecules than to rat-liver macromolecules when incubated at 37 degrees C in the presence of reduced nicotinamide adenine dinucleotide phosphate.

Mutat Res, 1983 Jan, 119(1), 27 - 34
Inactivation of potent pyrolysate mutagens by chlorinated tap water; Tsuda M et al.; The potent mutagens 3-amino-1-methyl-5H-pyrido{4,3-b}indole (Trp-P-2, 62450-07-1), 2-amino-6-methyldipyrido-{1,2-a:3', 2'-d}imidazole (Glu-P-1, 67730-11-4) and 2-amino-3-methylimidazo{4,5-f}quinoline (IQ, 76180-96-6), isolated from pyrolysates of tryptophan and glutamic acid and from broiled sardines, respectively, were effectively degraded by chlorinated tap water with a concomitant loss of mutagenicity toward Salmonella typhimurium TA98 and TA100 . The half-life of 10 microM IQ in the presence of 1.5 ppm of residual chlorine was less than 10 sec; those of Glu-P-1 and Trp-P-2 were 0.5-1 and 2-3 min, respectively . This means that a glass of chlorinated tap water (150 ml) containing 1.5 ppm of residual chlorine can break down about 200 micrograms of these pyrolysate mutagens within a couple of minutes.

Infect Immun, 1983 Jan, 39(1), 423 - 30
Histopathological study of protective immunity against murine salmonellosis induced by killed vaccine; Nakoneczna I et al.; Swiss-Webster mice were vaccinated with heat-killed salmonellae and then were infected with virulent Salmonella typhimurium . Only 1 of the 18 vaccinated mice died from a challenge of 10(4) X the 50% lethal dose, and about 70% of them survived a challenge of 10(5) X the 50% lethal dose . Histopathological examinations of the lesions developed in these vaccinated mice showed that they followed the characteristic features of a primary lesion in murine salmonellosis . There was an early necrosis with infiltration of polymorphonuclear leukocytes and abscess formation within the first 6 to 7 days after infection . However, these abscesses remained small and discrete . By days 7 to 10, the lesions began to transform into granulomas, first with the appearance of peripheral mononuclear cells and then by the replacement of polymorphs . By the third week of the infection, minute and discrete granulomas were seen scattered in the spleen, liver, and lymph nodes . Beyond this stage, healing and tissue regeneration followed . Thus, the characteristics of infectious lesions developed in mice vaccinated with heat-killed salmonellae are distinctly different from those developed in mice protected by the avirulent vaccine.

Carcinogenesis, 1983, 4(1), 45 - 8
Mutagenicity of 1,2-dimethylhydrazine towards Salmonella typhimurium, co-mutagenic effect of secondary biliary acids; Wilpart M et al.; Even though 1,2-dimethylhydrazine (DMH) is highly carcinogenic in experimental animals, it has not been shown to be clearly mutagenic in any of the short term tests in vitro . The present report demonstrates that DMH is mutagenic in the Ames test when it is incubated together with lithocholic or deoxycholic acid with or without metabolic activation . Such a co-mutagenic effect seems to be restricted to the secondary biliary acids since neither cholic nor chenodeoxycholic acid had the same activity . The secondary biliary acids are present in the colon where they are formed by bacteria . Such a co-mutagenic effect could thus be of importance with regard to the carcinogenic activity of DMH . It could also be relevant to colon carcinogenesis in humans.

Chem Biol Interact, 1983 Jan, 43(1), 67 - 71
The 1-nitropyrene reductase of Salmonella typhimurium; Lu C et al.; We have devised a sensitive fluorimetric assay to monitor the conversion of 1-nitropyrene to 1-aminopyrene . Application of this assay to extracts of Salmonella typhimurium strains TA98 and TA100 (which are sensitive to the mutagenic and lethal effects of 1-nitropyrene) has shown that these bacteria contain 'nitropyrene reductase' activity at the low level of 10(-11) mol/min/mg protein . NADPH and NADH serve equally well as reducing agents . The nitropyrene reductase activity of strain TA100 F50 (a mutant resistant to 1-nitropyrene) was found to be considerably lower.

Surgery, 1983 Jan, 93(1 Pt 2), 158 - 64
Toxicologic evaluation of metronidazole with particular reference to carcinogenic, mutagenic, and teratogenic potential; Roe FJ; The gastrointestinal tract and nervous system are the main targets for metronidazole toxicity . With the possible exception of certain neurotoxic effects in a few heavily treated patients, all the toxic effects of metronidazole are transient and reversible on withdrawal of the drug . Properly designed tests for embryotoxicity and teratogenicity in rats, rabbits, and mice have produced convincingly negative results, and no adverse effects on the fetus have been observed in women given the drug for trichomoniasis during various stages of pregnancy . The antimicrobial activity of metronidazole is thought to depend on its nitroreduction to form short-lived cytotoxic metabolites capable of reacting with deoxyribonucleic acid . It is therefore perhaps not surprising that metronidazole has been reported to be mutagenic for certain strains of Salmonella typhimurium . Metronidazole gave negative results in the mouse micronucleus test and no increase in sister chromatid exchanges or chromosomal aberrations in cultured human lymphocytes . Prolonged exposure to metronidazole in the treatment of patients with Crohn's disease was not associated with any increase in the frequency of chromosomal aberrations . Prolonged high-dose exposure of mice to metronidazole led to an increased incidence of lung tumors in three separate studies and to a suggestive increase in lymphoreticular neoplasia in female animals in one of the studies . These effects are probably nonspecific, since major effects on the incidence of neoplasms of the same and other kinds have been produced by merely varying the amount of a standard diet that mice consume . A reported excess of liver tumors in rats exposed to metronidazole can be explained by the fact that the authors failed to age standardize their data despite a big and highly significant beneficial effect of the drug on survival . Two carcinogenicity studies in hamsters have given entirely negative results . The follow-up for 10 or more years of 771 women first treated with metronidazole between 1960 and 1969 for trichomoniasis revealed no excess of any form of cancer attributable to treatment, and no excess cancer risk has so far come to light in the Kaiser-Permanente follow-up of nearly 2500 patients given at least one prescription of metronidazole between 1969 and 1973 . At the present time it is reasonable to conclude that this highly useful, and sometimes life-saving, drug is essentially free of cancer risk or other serious toxic side effects.

J Bacteriol, 1983 Jan, 153(1), 506 - 10
Excretion of flagellin by a short-flagella mutant of Salmonella typhimurium; Ikeda T et al.; A nonmotile mutant of Salmonella typhimurium, SJW1254, has very short flagella (less than 0.1 micron long) due to a mutation in the structural gene of flagellin (H2) . When ammonium sulfate was added to the culture medium of SJW1254 grown to the late-log phase, a large amount of protein precipitated . Gel electrophoresis and immunodiffusion showed that more than 90% (wt/wt) of the precipitated protein was flagellin . The mutant flagellin appeared to be excreted in the monomeric form, in an amount comparable to the amount in the flagellar filaments of wildtype bacteria . No such precipitate was obtained from the medium of wild-type bacteria . The mutant flagellin had the same apparent molecular weight (55,000) and isoelectric point (5.3) as the wild-type flagellin, but differed in mobility in polyacrylamide gel electrophoresis under nondenaturing conditions . Moreover, the mutant flagellin did not polymerize in vitro under various conditions in which wild-type flagellin polymerized . These results suggested that the mutant bacteria excreted flagellin because the flagellin polymerized poorly and therefore could not be trapped at the tip of the flagellar filament . This short-flagella mutant should be useful for studying the mechanism of flagellin transport.

J Bacteriol, 1983 Jan, 153(1), 350 - 6
Degradation of proline peptides in peptidase-deficient strains of Salmonella typhimurium; Miller CG et al.; A mutant strain of Salmonella typhimurium that lacks two proline-specific peptidases (peptidases P and Q) could not complete the degradation of proline peptides formed as intermediates in starvation-induced protein breakdown . The wild-type strain produced free proline as the product of degradation of proline-labeled proteins . The pepP pepQ mutant, however, produced a mixture of small proline peptides . In the absence of peptidase Q only, peptidase P could complete the degradation of most of the proline peptide intermediates formed . In the absence of peptidase P only, about 50% of the proline-labeled, acid-soluble products were proline peptides . These results are consistent with in vitro specificity data indicating that peptidase Q hydrolyzes X-Pro dipeptides only, whereas peptidase P attacks both X-Pro dipeptides and longer peptides with X-Pro at their N-termini . A mutant strain lacking four broad-specificity peptidases (peptidases N, A, B, and D), but containing peptidases P and Q, also produced proline peptides as products of protein breakdown . This observation suggests that broad-specificity peptidases are required to generate the X-Pro substrates of peptidases P and Q . A strain lacking six peptidases (N, A, B, D, P, and Q) was constructed and produced less free proline from protein breakdown than either the pepP pepQ strain or the pepN pepA pepB pepD strain . These observations suggest that the degradation of peptide intermediates involves the sequential removal of N-terminal amino acids and requires both broad-specificity aminopeptidases (peptidases N, A, and B) and the X-Pro-specific aminopeptidase, peptidase P.

Microbiol Immunol, 1983, 27(10), 861 - 7
Isolation and partial properties of a porin-like protein from Vibrio parahaemolyticus cell envelope; Koga T et al.; The cell envelope of Vibrio parahaemolyticus pilot strain K-11 contains a major protein with an apparent molecular weight of 35,000 which was not solubilized with 2% sodium dodecyl sulfate (SDS) at 50 C for 30 min and was resistant to trypsin . The protein was extracted from the SDS-insoluble envelope with SDS containing 0.4 M NaCl and purified by acetone precipitation and gel filtration . The purified protein was completely dissociated into a monomer with a molecular weight of 35,000 in SDS at 60 C . The amino acid composition of the protein was nearly the same as that of porins from Escherichia coli and Salmonella typhimurium . Thus the protein seems to be porin-like.

Mol Gen Genet, 1983, 192(3), 477 - 86
Regulatory interactions among the cya, crp and pts gene products in Salmonella typhimurium; Dobrogosz WJ et al.; A well-characterized set of pts deletion mutants of Salmonella typhimurium were used to re-evaluate the purported role of the PTS in the inducer exclusion process and in regulation cAMP synthesis . During the course of these studies a class of secondary mutations was isolated which suppress the inhibition of cAMP synthesis caused by pts mutations . These suppressor mutations were traced to the crp locus and tentatively designated as acr (adenylate cyclase regulation) mutations . A new model is proposed in which CRP rather than adenylate cyclase is believed to be the central regulatory element in the catabolite repression phenomenon.

Mol Gen Genet, 1983, 191(3), 413 - 20
Gene organization in the distal part of the Salmonella typhimurium histidine operon and determination and sequence of the operon transcription terminator; Carlomagno MS et al.; Several transducing phages, carrying different deletions of the Salmonella typhimurium histidine operon were constructed and mapped . These phages were used to obtain fragments of DNA comprising different regions of the operon, which were subcloned in plasmid vectors . The recombinant plasmids allowed the construction of a physical and restriction map of the histidine operon . The presence of the different genes on individual fragments was confirmed by complementation tests . The transcription termination site of the histidine operon has been established by S1 mapping and sequence analysis . The entire operon measures about 7100 base pairs and the last six structural genes are contained in 3450 bases of genetic materials.

Dev Biol Stand, 1983, 53, 47 - 54
Aromatic-dependent "Salmonella sp." as live vaccine in mice and calves; Stocker BA et al.; A block in the common aromatic biosynthesis (aro) pathway makes E . coli, Salmonella, etc., exacting for aromatic metabolites; two of these, paraaminobenzoic acid and dihydroxybenzoic acid, are not mammalian metabolites . Bacteria needing substances not available in host tissues should be unable to grow there and so be non-virulent . Transposon-generated deletion and deletion-inversion mutations at aroA caused loss of mouse virulence in Salmonella typhimurium; e.g., LD50, intraperitoneal route, increased from less than 10 to greater than 10(6), and LD50 by feeding increased from ca . 10(5) to greater than 10(8) . Furthermore, a single injection of 10(5) live aro- bacteria protected mice of a Salmonella-susceptible line, BALB/c, against challenge, 4 weeks later, with 5 X 10(5) virulent S . typhimurium (i.e., greater than 10(4) LD50); a single dose of the live-vaccine strain given i.p . also protected against challenge one month later by feeding 2 X 10(7) of a virulent strain . Mice vaccinated by feeding 2 X 10(8) live aro- bacteria were unaffected by feeding, one month later, 2 X 10(7) of a virulent S . typhimurium strain ( = ca 100 LD50) . Intravenous injection of microparticulate silica did not reduce the mouse i.p . LD50 of an aro- strain, and 3 i.p . injections of cyclophosphamide, 4 mgm, caused only a small reduction . Thus the reduced virulence of the aro- strain does much depend on the integrity of host cellular defense mechanisms . Non-reverting aro- derivatives made from proven calf-virulent S . typhimurium and S . dublin strains are being tested at the School of Veterinary Medicine, University of California at Davis . None of 26 calves given aro- live-vaccine bacteria intramuscularly (usually 10(9)) and none of 8 calves fed ca . 10(11) live aro- bacteria, died or became seriously ill . Vaccinated and control calves were challenged by feeding 10(11) bacteria of a virulent strain, S . typhimurium or S . dublin . This challenge caused death of 14 of 16 non-vaccinated calves . The results, to date, in vaccinated animals indicate that one aro- strain of each of the two Salmonella species is effective if given as a live vaccine in two intramuscular doses.

Carcinogenesis, 1983, 4(6), 647 - 52
Carcinogenesis and atherogenesis: differences in monooxygenase inducibility and bioactivation of benzo{a}pyrene in aortic and hepatic tissues of atherosclerosis-susceptible versus resistant pigeons; Majesky MW et al.; Atherosclerosis-susceptible White Carneau (WC-2) pigeons were compared with atherosclerosis-resistant Show Racer (SR-39) pigeons in terms of hepatic and aortic biotransformation and bioactivation of benzo{a}pyrene (B{a}P) . Following pretreatment of the two strains with 3-methylcholanthrene (MC, 40 mg/kg), WC-2 hepatic 9000 X g supernatant fractions (S-9) exhibited consistently greater increases in the production of specific B{a}P metabolites when compared with uninduced controls than did the corresponding SR-39 preparations . Analyses of organic solvent-extractable metabolites with h.p.l.c . revealed that inducer pretreatment resulted in significantly greater increases (18- versus 7-fold) in the generation of B{a}P-7,8-dihydrodiol by WC-2 versus SR-39 hepatic S-9 . Similar differences in inducibility were found for most other metabolites appearing in the h.p.l.c . profiles . Hepatic monooxygenase systems were induced in both strains following treatment of pigeons with a mixture of polychlorinated biphenyls (Aroclor 1254, 500 mg/kg); WC-2 birds again demonstrated greater responsiveness . Bioactivation of B{a}P to mutagenic (but not cytotoxic) products by hepatic S-9 was more effective in preparations from MC-pretreated WC-2 versus SR-39 pigeons when assessed with Salmonella typhimurium tester strains . Aortic homogenates from MC-pretreated pigeons displayed even greater inducibility differences than were observed with hepatic preparations . Inducer-mediated increases in the formation of B{a}P-7,8- and B{a}P-9,10-dihydrodiols were approximately 10- and 12-fold greater in WC-2 than SR-39 aortic preparations, respectively . The results document marked differences in biotransformation and bioactivation of carcinogenic hydrocarbons by atherosclerosis-susceptible and resistant pigeons and are reminiscent of the metabolic differences observed in carcinogenesis-susceptible and resistant strains of mice . It is suggested that these pigeon strains might offer a promising system in which to further study the role of target tissue biotransformation in the atherogenic actions of polynuclear aromatic hydrocarbons.

Environ Mutagen, 1983, 5(3), 311 - 8
Rat nasal tissue activation of benzo(a)pyrene and 2-aminoanthracene to mutagens in Salmonella typhimurium; Bond JA et al.; Cytochrome P-450-dependent monooxygenase activity has been measured in the nasal turbinates of dogs and rats . The capacity of male Fischer-344 rat nasal tissue to bioactivate benzo(a)pyrene (BaP) and 2-aminoanthracene (2-AA) to mutagens in Salmonella typhimurium was investigated . 2-AA was mutagenic in strains TA98 and TA100 when nasal tissue S-9 was utilized as the activating enzyme system and BaP was mutagenic in strain TA100 . At all doses and protein concentrations tested, 2-AA displayed nearly 500-1000 times greater bacterial mutagenicity than BaP . In strain TA-100, nasal tissue S-9 was approximately twice as active toward 2-AA as lung S-9 and 75% as active as liver S-9 . Aryl hydrocarbon hydroxylase activity was detected in rat nasal tissue when 14C-BaP was used as a substrate . Rat nasal tissue metabolized BaP to several oxidized metabolites which included dihydrodiols, quinones, and phenols . 3-Hydroxybenzo(a)pyrene and BaP-3, 6-quinone were the major metabolites detected (150 pmoles/mg protein/30 min) . These results indicate that rat nasal tissue can metabolize promutagens to reactive species which may play an important role in xenobiotic-induced nasal tumors.

Carcinogenesis, 1983, 4(1), 93 - 6
Specificity of rat liver cytochrome P-450 isozymes in the mutagenic activation of benzo{a}pyrene, aromatic amines and aflatoxin B1; Robertson IG et al.; The ability of three purified forms of rat liver cytochrome P-450 to metabolically activate benzo{a}pyrene, trans-benzo-{a}pyrene-7,8-dihydrodiol, 2-aminofluorene, aflatoxin B1, dimethylnitrosamine, and a pyrolysis product of tryptophan(3-amino-1-methyl-5H-pyrido(4,3-b)indole) (Trp-P-2) to mutagenic products was examined using Salmonella typhimurium strains TA98 and G46 in a reconstituted monooxygenase system . The isozymes examined were cytochrome P-450-PB (the major phenobarbital inducible form), and the two major 3-MC inducible forms (cytochromes P-448(52) and P-448(55)) . Cytochromes P-448(52) and P-448(55) preferentially metabolize 2-aminofluorene and Trp-P-2 to mutagenic products . However, only cytochrome P-448(55) metabolizes benzo{a}pyrene and its 7,8-dihydrodiol derivative to mutagenic products . Both cytochrome P-448(52) and P-448(55) metabolize aflatoxin B1 to mutagenic products at a much faster rate than cytochrome P-450-PB . Dimethylnitrosamine was not activated by any of the isozymes tested.

Allerg Immunol (Leipz), 1983, 29(3), 160 - 7
Depressed macrophage functions at temperatures below 37 degrees C; Ganguly R et al.; Immunobiological properties of guinea pig and human peritoneal macrophages were studied at temperatures ranging from 25 degrees C to 37 degrees C . Glass adherence, random migration, response to MIF and killing of Salmonella typhimurium and Saccharomyces cerevesiae by guinea pig macrophages were decreased with temperatures below 37 degrees C . Killing of Sacch . cerevesiae by human macrophages was also reduced at temperatures less than 37 degrees C . Acid phosphatase and beta-N-acetylglucosaminidase (NAG) activity assayed at 37 degrees C did not change when the cells were preincubated for 1 and 5 hours at various temperatures . Impaired macrophage function with subnormal temperatures may contribute to enhanced susceptibility to infection of patients with chronic diseases such as renal failure and cirrhosis.

C R Seances Soc Biol Fil, 1983, 177(2), 149 - 57
{Use of scanning electron microscopy coupled with transmission electron microscopy in comparative studies of the relation between Schistosoma mansoni and Salmonella typhimurium}; Bouillard C et al.; Relations between Schistosoma mansoni and Salmonella typhimurium are studied in vivo and in vitro using scanning and transmission electron microscopy as complementary methods . Salmonellae adhesion is a specific process materialized in special places of male and mature schistosome tegumental surface . Interactions are marked by bacterial strong fibres creating a network all around Schistosoma where Salmonellae are dividing . Membrane junction is the last stage leading to symbiotic balance between two biologic systems.

Carcinogenesis, 1983, 4(7), 867 - 71
Biological activity of benzylating N-nitroso compounds . Models of activated N-nitrosomethylbenzylamine; Wiessler M et al.; Unsymmetrically substituted N-nitrosomethylbenzylamine is an oesophageal carcinogen with potential methylating and benzylating properties . Whereas the methylating activity of the compound has been investigated, little is known of its potential benzylating properties . In order to elucidate the biological consequences of benzylation, related model compounds which are presumed benzylating agents were synthesized and tested for mutagenicity . N-nitrosobenzylurea and its structural analogue N-nitroso-p-methylbenzylurea were direct acting mutagens in Salmonella typhimurium TA 98 . Activity was also present in TA 1535, but it was less pronounced . N-nitroso-alpha-acetoxybenzyl-benzylamine was equally mutagenic in S . typhimurium TA and TA 1535 . N-nitroso-acetoxymethyl-benzylamine and N-nitrosoacetoxy-methyl-p-methylbenzylamine are two model compounds which may decompose by hydrolysis or through esterases to yield intermediates also though to arise after alpha-C hydroxylation of the methyl group of the parent nitrosamines . These compounds needed additional activation by enzymes present in the post-mitochondrial supernatant of rat liver . They were distinctly mutagenic in TA 98 . Furthermore, all compounds also caused the induction of phage lambda in a qualitative assay with Escherichia coli Br 513 . Thus, benzylation of DNA clearly results in a biological consequence . These findings are supportive of the theory that if enzymic attack occurs on the methyl group of N-nitrosomethylbenzylamine, benzylation may also contribute to the overall biological activity of the compound.

Mol Gen Genet, 1983, 189(3), 463 - 70
Construction and use of pyr::lac fusion strains to study regulation of pyrimidine biosynthesis in Salmonella typhimurium; Michaels G et al.; The technique developed by Rosenfeld and Brenchley {J Bacteriol 144, 848-851 (1980)} has been used to introduce Mu d1 (Apr lac) into Salmonella typhimurium for purposes of constructing pyr::lac fusion strains . A stable pyrB::lac fusion mutant was subsequently derived and used for the genetic characterization of the pyrB gene . The direction of transcription of pyrB was determined to be counterclockwise on the S . typhimurium linkage map and argI was shown to be located clockwise of pyrB . Mutants altered in the regulation of expression of pyrB were isolated and two of the isolates chosen for further study were tentatively categorized as promoter or operator mutants.

Genetics, 1983 Jan, 103(1), 31 - 42
Genetic characterization of the sufj frameshift suppressor in Salmonella typhimurium; Bossi L et al.; A new suppressor of +1 frameshift mutations has been isolated in Salmonella typhimurium . This suppressor, sufJ, maps at minute 89 on the Salmonella genetic map between the argH and rpo(rif) loci, closely linked to the gene for the ochre suppressor tyrU(supM) . The suppressor mutation is dominant to its wild-type allele, consistent with the suppressor phenotype being caused by an altered tRNA species . The sufJ map position coincides with that of a threonine tRNA(ACC/U) gene; the suppressor has been shown to read the related fourbase codons ACCU, ACCC, ACCA.--The ability of sufJ to correct one particular mutation depends on the presence of a hisT mutation which causes a defect in tRNA modification . This requirement is allele specific, since other frameshift mutations can be corrected by sufJ regardless of the state of the hisT locus.--Strains carrying both a sufJ and a hisT mutation are acutely sensitive to growth inhibition by uracil; the inhibition is reversed by arginine . This behavior is characteristic of strains with mutations affecting the arginine-uracil biosynthetic enzyme carbamyl phosphate synthetase . The combination of two mutations affecting tRNA structure may reduce expression of the structural gene for this enzyme (pyrA).

Teratog Carcinog Mutagen, 1983, 3(6), 503 - 13
Mutagenicity (Ames): a structure-activity model; Enslein K et al.; A statistical structure-activity model of the Salmonella typhimurium (Ames) test has been devised based on 472 chemicals for which this endpoint has been measured . The model uses substructural fragments as the independent parameters to explain the difference in mutagenicity of the different chemicals . The model is able to classify 86% of the chemicals into their correct categories; the false-positive rate is 4.7%, and the false-negative rate 5.3% . Approximately 10% of the chemicals cannot be classified by the existing equation . This structure-activity model can be used as a preliminary screen prior to other testing as well as for setting priorities for more detailed investigations.

Teratog Carcinog Mutagen, 1983, 3(6), 491 - 501
The effects of excision repair and the plasmid pKM101 on the induction of his+ revertants by chemical agents in Salmonella typhimurium; Inman MA et al.; Expansion of the Ames Salmonella/microsome mutagenesis test to include plasmid pKM101-bearing, excision repair-proficient derivatives permits 1) the identification of mutagens that require both factors for activity; 2) the identification of genotoxins through the enhancement of survival by excision repair; and 3) the classification of substances according to the effects of excision repair on their mutagenesis . Class I includes substances that require excision repair to effect mutagenesis . Class II contains substances whose mutagenesis is not affected by excision repair . Class III mutagens cause premutational lesions in DNA which are readily removed by excision repair . This classification scheme is suggested as a preliminary step in making a risk estimation for a mutagen.

Teratog Carcinog Mutagen, 1983, 3(5), 429 - 38
Quantitative relationship between structure and mutagenic activity in a series of 5-nitroimidazoles; Biagi GL et al.; The mutagenic activity of 20 5-nitroimidazoles was tested in Salmonella typhimurium TA-100 strain by means of the Ames test . A multiple regression analysis using the interaction term MR2 X Hb and the chromatographic Rm values yielded the equation: (formula see text); where C is the molar concentration (1 M X 10(-6) of each drug increasing the revertants by five times in the Ames test . The interaction term MR2 X Hb takes into account the positive effect exerted by substituents characterized by higher molar refractivity (MR2) and capable of hydrogen bonding (Hb) . It was found that when the electroreduction potentials (EIc.p.) were included, the correlation was not improved.

Mol Gen Genet, 1983, 192(1-2), 187 - 97
Regulation of transcription of glnA, the structural gene encoding glutamine synthetase, in glnA::Mu d1 (ApR, lac) fusion strains of Salmonella typhimurium; Krajewska-Grynkiewicz K et al.; Using the Casadaban Mu d1 phage (Casadaban and Cohen 1979) we fused cis-acting regulatory sites for the Salmonella typhimurium glnA gene, the structural gene encoding glutamine synthetase, to lacZ so that transcription of lacZ was controlled by the glnA promoter-operator . Activities of beta-galactosidase in two glnA::Mu d1 fusion strains were high, approximately 25% and 125% the induced level of beta-galactosidase when transcription of lacZ is under control of the lac promoter, indicating that glutamine synthetase is not required to activate transcription of its own structural gene . Introduction of nitrogen regulatory mutations ntrA::Tn10 or ntrC::Tn10 into fusion strains resulted in greatly decreased synthesis of beta-galactosidase indicating that the positive regulatory factors encoded by ntrA and ntrC activate glnA expression at the level of transcription . Comparison of beta-galactosidase activities in fusion strains with those in fusions carrying ntrC or ntrA mutations indicated that: 1) the magnitude of activation of glnA expression is at least 43-fold; 2) the magnitude of repression is approximately 13-fold and repression occurs at the level of transcription; 3) the degree of modulation of glnA expression by ntr products is at least 560-fold (13 X 43); and 4) glutamine synthetase is not required for repression of transcription of its own structural gene . In contrast to strains carrying non-polar mutations in glnA, strains carrying glnA insertion mutations, including glnA::Mu d1 fusions, are apparently defective in activating expression of some nitrogen controlled genes other than glnA . Defects cannot be accounted for by the absence of glutamine synthetase protein or catalytic activity; they appear to be due to decreased expression of nitrogen regulatory genes ntrB and/or ntrC, which are adjacent to glnA.

Teratog Carcinog Mutagen, 1983, 3(4), 377 - 93
Genotoxicity and teratogenicity of diphenyl and diphenyl ether: a study of sea urchins, yeast, and Salmonella typhimurium; Pagano G et al.; This study was designed to investigate the possible genotoxic and teratogenic actions of diphenyl (DP), diphenyl ether (DPE), and their eutectic mixture, in a comparative approach including different test systems . Two microbial systems and a metazoan model were used: (1) diploid D7 strain of Saccharomyces cerevisiae; (2) Salmonella typhimurium strains TA100, TA98, TA1535, TA1537, TA1538, TA1532, TA2636; and (3) sea urchins (Paracentrotus lividus and Sphearechinus granularis) . Both compounds resulted in severe toxicity in all of test organisms at levels greater than or equal to 10(-5) M (approximately 2 ppm) . DP caused genetic effects in yeast with and without activating system, while the two chemicals appeared to be ineffective in Salmonella up to toxic levels . The action of DP and DPE on sea urchins resulted in developmental defects and mitotic abnormalities, following exposure of embryos or by pretreatment of sperm or eggs . In this system DPE appeared to be more effective than DP by about one order of magnitude (minimal active concentrations: 10(-5) M vs 10(-4) M) . The eutectic mixture, industrially used as a heat transfer medium, was tested in its virgin and used form, for genotoxicity and embryotoxicity . The latter appeared to be more effective than the virgin eutectic . This increase in the embryo- and genotoxicity of the used eutectic may be related to the appearance of newly formed compounds in the heat transfer process . These compounds have been separated by high-pressure liquid chromatography and detected by fluorimetry.

Teratog Carcinog Mutagen, 1983, 3(4), 367 - 76
Effect of incubation and activation conditions on the hepatocyte-mediated plate incorporation and preincubation Salmonella typhimurium mutagenesis assays; Williams K et al.; Primary cell-mediated microbial mutagenesis assays have been shown to be useful in detecting specific target organ genotoxic activity . The lack of a standard protocol for these assays, however, makes interlaboratory comparisons difficult . In order to standardize the hepatocyte-mediated Salmonella typhimurium mutagenesis assay, incubation and activation conditions for the plate incorporation and preincubation assays were examined using two aromatic amines, 2-aminofluorene (AF) and 2-acetylaminofluorene (AAF) . Direct comparison of two preincubation protocols demonstrated the necessity for the hepatocytes to be present during the two- to three-day plate incubation period . An examination of various preincubation times showed relatively minor differences between 15 and 90 minutes . The preincubation and plate incorporation protocols were directly compared using both hamster and rat hepatocytes . For both preincubation and plate incorporation, the optimum concentration of hepatocytes was shown to be 1 X 10(6)/plate . Direct evaluation of various hepatocyte-mediated bacterial protocols should facilitate future interlaboratory comparisons using a more standardized procedure.

Mol Gen Genet, 1983, 190(1), 20 - 6
Genetic fine structure of the tricarboxylate transport (tct) locus of Salmonella typhimurium; Somers JM et al.; The tct (tricarboxylate transport) locus of Salmonella typhimurium is found at 59 units between nalB and pheA (Somers et al . 1981) . This locus was further resolved by fine structure genetic mapping and by analysis of one of the gene products, the tricarboxylate binding protein (C protein) . 135 independent fluorocitrate resistant clones were isolated and 12 point mutants were ordered by 3 point reciprocal crosses using an adjacent Tn10 insertion . Eight spontaneous deletions as well as 17 deletions arising from imprecise excisions of internal and flanking Tn10 elements were used to construct a deletion map comprising 21 deletion segments . 115 strains were than assigned to these segments to complete the fine-structure map . Using the expression of the C protein as a guide, an analysis of a variety of mutant strains indicated: that the tct locus is composed of at least four genes and transcription is clockwise; the C protein structural gene (tctC) resides in the centre of the region and codes for two isoelectric forms of the C gene product; tctC is flanked by two regions which are involved in transport but whose gene products are not yet identified.

Teratog Carcinog Mutagen, 1983, 3(2), 205 - 13
Criteria for the standardization of Salmonella mutagenicity tests: results of a collaborative study . IV . Relationship between the number of his- bacteria plated and number of his+ revertants scored in the Salmonella mutagenicity test; Goggelmann W et al.; Five laboratories participated in a joint ring study to investigate the role of bacterial cell number in the Salmonella mutagenicity test . A strictly standardized protocol, using sodium azide and TA 1535, was developed and employed to test the mutagenicity of N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) with different dilutions of Salmonella typhimurium TA-100 and TA-1535 cultures . All laboratories detected the mutagenic activity of sodium azide with only a 2-fold variation of test results . For MNNG the interlaboratory variation was approximately 5-fold . Decreasing numbers of test bacteria employed resulted in lower numbers of MNNG-induced revertants in all laboratories . The number of preexisting revertants decreased in direct proportion to the reduced cell content, whereas the number of spontaneous revertants was not as greatly affected . A critical amount of test bacteria was required in order to obtain numbers of induced revertants which were equal to twice the number of spontaneous revertants . Two evaluation parameters which may be employed to describe the mutagenicity of a compound are compared.

Teratog Carcinog Mutagen, 1983, 3(2), 187 - 93
Criteria for the standardization of Salmonella mutagenicity tests: results of a collaborative study . II . Studies to investigate the effect of bacterial liquid culture preparation conditions on Salmonella mutagenicity test results; Herbold BA et al.; The influence of various parameters and growth conditions in the "overnight culture" of Salmonella typhimurium strains on mutagenicity test results was investigated . A number of factors were first suspected to be of some importance for the quantitative outcome of the mutagenicity test . None of them, however, was found to influence the results to such a marked extent as to be a major source of variability . Only the brand of nutrient broth used for the propagation of the bacteria proved finally to have a certain effect on the number of (spontaneous and induced) revertant colonies, although no precise and quantitative statements can be made with regard to a possible standardization of this experimental segment in the Salmonella mutagenicity test . The occurrence of such unpredictable but noticeable influences is, however, evidence for the importance of an intralaboratory optimization and standardization of all parts of the test procedure.

Teratog Carcinog Mutagen, 1983, 3(1), 51 - 63
Mutagenicity of a series of 25 nitroimidazoles and two nitrothiazoles in Salmonella typhimurium; Cantelli-Forti G et al.; Twenty-five 5-nitroimidazole and two 5-nitrothiazole derivatives were tested for mutagenicity as well as for antibacterial activity in Salmonella typhimurium TA-100 strain . Many of these compounds such as metronidazole, azanidazole, nimorazole, carnidazole, ornidazole, tinidazole, etc are extensively used in human chemotherapy, and some of them were recently synthetized for possible clinical trials as hypoxic cell specific radiosensitizers . Both mutagenic and antibacterial activity were shown for 22 of the test compounds . The high correlation between mutagenic and antibacterial activity supports the hypothesis of a same mechanism for both activities . The present results confirm that the mutagenicity of the nitroheterocyclic compounds is not separated from other biological activities, such as antimicrobial activity.

FEBS Lett, 1982 Dec 27, 150(2), 434 - 8
DNA-binding of IQ, Me-IQ and Me-IQx, strong mutagens found in broiled foods; Watanabe T et al.; Non-covalent DNA-binding has been studied of 2-amino-3-methylimidazo{4,5-f}quinoline (IQ), 2-amino-3,4-dimethylimidazo{4,5-f}quinoline (Me-IQ) and 2-amino-3,8-dimethylimidazo{4,5-f}quinoxaline (Me-IQx), strong mutagens found in broiled foods . These mutagens are intercalated into DNA, as found by ultraviolet absorption and gel electrophoresis . The binding of IQ is stronger with GC pairs than AT pairs in DNA . The binding constants with calf thymus DNA are 1.6 X 10(6) (Me-IQ), 0.9 X 10(6) (IQ) and 0.7 X 10(6) M-1 (Me-IQx) at pH 6.0 . This order of DNA affinity agrees with the order of mutagenicity towards Salmonella typhimurium TA98.

Int J Cancer, 1982 Dec 15, 30(6), 719 - 24
Inhibitory effects of phenolics, teas and saliva on the formation of mutagenic nitrosation products of salted fish; Stich HF et al.; The objectives of this study were to simulate in vitro some of the conditions that may prevail in man during the ingestion of a meal and to quantitate the inhibitory effect of phenolics and phenolic-containing beverages on the formation of mutagenic nitrosation products . The test system consisted of nitrosating (pH 2, 1 h, 37 degrees C) an aqueous fraction of a salt-preserved Chinese fish (Pak Wik) with or without the inhibitors to be tested and estimating the frequency of his+ revertants per survivor of Salmonella typhimurium (strain TA1535) . The phenolics and teas were added to the nitrosation mixture . Catechin, chlorogenic acid, gallic acid, pyrogallol and tannic acid suppressed the formation of mutagenic nitrosation products . The inhibitory efficiency was comparable to that of ascorbic acid . A Japanese, a Chinese and a Ceylonese tea also prevented the formation of mutagenic nitrosated fish products at doses which are usually consumed by man . Moreover, saliva exerted an inhibitory effect . The inhibitory effect was not additive when the phenolics or saliva were added concurrently to the nitrosation mixture . The possibility that phenolics are involved in the apparent chemopreventive effect of fruits and vegetables is discussed.

J Biol Chem, 1982 Dec 10, 257(23), 14553 - 64
Sugar transport by the bacterial phosphotransferase system . Regulation of other transport systems (lactose and melibiose); Mitchell WJ et al.; The role of the phosphoenolpyruvate-dependent phosphotransferase system (PTS) in the phenomenon of inducer exclusion was examined in whole cells of Salmonella typhimurium which carried the genes of the Escherichia coli lactose operon on an episome . In the presence of the PTS substrate methyl alpha-D-glucopyranoside, the extent of accumulation of the lactose analog methyl beta-D-thiogalactopyranoside was reduced . A strain carrying a mutation in the gene for Enzyme I was hypersensitive to the PTS effect, while a crr mutant strain was completely resistant . Influx, efflux, and exchange of galactosides via the lactose "permease" were inhibited by methyl alpha-glucoside . This inhibition occurred in the presence of metabolic energy poisons, and therefore does not involve either the generation of metabolic energy or energy-coupling to the lactose transport system . When the cellular content of the lactose permease was increased by induction with isopropyl beta-D-thiogalactopyranoside, cells gradually became less sensitive to inducer exclusion . The extent of inhibition of methyl beta-thiogalactoside accumulation by methyl alpha-glucoside was shown to be dependent on the relative cellular content of the PTS and lactose system . The data were consistent with an hypothesis involving partial inactivation of galactoside transport due to interaction between a component of the PTS and the lactose permease . By examination of the effects of the PTS and lactose uptake and melibiose permease-mediated uptake of methyl beta-thiogalactoside, it was further shown that the manner in which inducer exclusion is expressed is independent on the routes available to the non-PTS sugar for exit from the cell.

J Biol Chem, 1982 Dec 10, 257(23), 14565 - 75
Sugar transport by the bacterial phosphotransferase system . Preparation and characterization of membrane vesicles from mutant and wild type Salmonella typhimurium; Beneski DA et al.; Modifications of published procedures (reviewed by Kaback, H . R . (1974) Science (Wash . D . C.) 186, 882-892) were developed for preparing membrane vesicles from Salmonella typhimurium . The preparations consisted largely of closed, unilamellar structures and contained inner membrane with little to no contamination by outer membrane or cell wall . A variety of cytoplasmic proteins was assayed in the membrane preparations, and they were found to be present at low to trace levels, whereas other proteins known to be associated with membranes were found at high levels (with respect to specific activities) in the vesicle preparations . At least 90% of the vesicles appeared to be oriented right-side-out; we do not know whether the remaining 10% represents closed vesicles oriented inside-out or "leaky" right-side-out vesicles . The vesicle preparations were impermeable to both low and high molecular weight solutes, for example, to both intra- and extravesicular sucrose . In double label experiments, the vesicle volumes were found to be about 6 microliters/mg of protein for preparations isolated from the wild type strain, and about 4.5 microliters/mg of protein for vesicles isolated from a mutant, SB2950, deleted in ptsH, ptsI, and crr genes (proteins HPr, Enzyme I, and IIIGlc, respectively) . One advantage of S . typhimurium over Escherichia coli for these studies is that the former can be induced to take up phosphoenolpyruvate . This may be the reason that S . typhimurium vesicles transported methyl alpha-glucoside at 4- to 100-fold the rates reported for vesicles from E . coli, while uptake rates of proline were comparable in the two types of preparations . Vesicles from strain SB2950 were unable to take up methyl alpha-glucoside, but the transport (and phosphorylating) system was reconstituted in the vesicles by trapping the soluble purified proteins inside the vesicles during preparation of the latter . All three proteins were required for reconstruction . Studies with intra- and extravesicular soluble proteins of the phosphoenolpyruvate:glucose phosphotransferase system showed that the IIMan complex, which phosphorylates glucose, 2-deoxyglucose, and other sugars, is symmetrically oriented in the membranes . That is, this complex could phosphorylate 2-deoxyglucose when supplemented with Enzyme I and HPr either inside or outside of the membranes, and the sugar phosphate was found on the same side of the membranes as the soluble phosphotransferase system proteins . The integral membrane protein, II-BGlc, which phosphorylates glucose and methyl alpha-glucoside, showed contrasting behavior . Methyl alpha-glucoside phosphate was formed (intravesicularly) only when the soluble proteins (Enzyme I, HPr, and IIIGlc) were located inside the vesicles . Thus, II-BGlc appears to be asymmetrically oriented in the membranes.

J Biol Chem, 1982 Dec 10, 257(23), 14526 - 37
Sugar transport by the bacterial phosphotransferase system . Isolation and characterization of a glucose-specific phosphocarrier protein (IIIGlc) from Salmonella typhimurium; Meadow ND et al.; The phosphocarrier protein, IIIGlc, of the phosphoenolpyruvate:glycose phosphotransferase system (PTS) was purified to homogeneity by two methods . The first method utilized ion exchange and gel filtration chromatography, isoelectric focusing, and polyacrylamide gel electrophoresis, and required several weeks for completion . The second method utilized and antibody affinity column plus two additional steps and could be completed in a few days . By both procedures, two forms of IIIGlc were isolated, which were called IIIGlc Slow and IIIGlc Fast on the basis of their relative mobilities in polyacrylamide gels . IIIGlc Fast is derived from IIIGlc Slow by cleavage of the seven NH2-terminal amino acids from the latter protein . Both IIIGlc Slow and IIIGlc Fast have Mr approximately 20,000; neither protein contains cysteine, tyrosine, or tryptophan . IIIGlc Slow is very stable to heat; only 50% of its sugar phosphorylating activity is lost after 1 h at 100 degrees C . The phosphoryl group in IIIGlc Slow appears to be linked to a histidinyl residue . Direct transfer of the phosphoryl group from HPr (the histidine-containing phosphocarrier protein of the PTS) to IIIGlc slow was demonstrated as well as the reverse reaction . In addition, phospho-IIIGlc Slow served as a phosphoryl donor to methyl alpha-glucoside (or glucose) in the absence of all other PTS components except the partially purified integral membrane protein specific for this sugar, II-BGlc . The loss of the seven amino acids from IIIGlc Slow (giving IIIGlc Fast) leads to a marked alteration in the kinetic properties of the protein in the phosphotransferase system . IIIGlc Slow accepts 1 mol of phosphate from phosphoenolpyruvate via Enzyme I and HPr (the histidine-containing phosphocarrier protein) and participates in the phosphorylation of glucose or methyl alpha-D-glucoside . IIIGlc Fast also accepts 1 mol of phosphate, but phospho-IIIGlc Fast is only 2-3% as active as phospho-IIIGlc Slow in the phosphorylation of sugar . IIIGlc Fast is found only in trace quantities in living cells, and may play a role in the regulation of non-PTS sugar transport systems.

J Biol Chem, 1982 Dec 10, 257(23), 14518 - 25
Sugar transport by the bacterial phosphotransferase system . Nanosecond fluorescence studies of the phosphocarrier protein (HPr) labeled at the NH2-terminal methionine; Hildenbrand K et al.; HPr is a low molecular weight, phosphocarrier protein of the Salmonella typhimurium phosphoenolpyruvate:glycose phosphotransferase system (PTS) . This protein was alkylated with the fluorescent reagent (N-iodoacetylaminoethyl)-5-naphthylamino-1-sulfonate under conditions which favor alkylation of the thioether linkage in methionine residues (Link, T . P . and Stark, G . R . (1968) J . Biol . Chem . 243, 1082-1088) to give the corresponding sulfonium derivatives . The isolated fluorescent protein (95-100% pure) was as active as native HPr both as a phosphoryl acceptor protein (phosphoenolpyruvate and Enzyme I of the PTS), and as a phosphocarrier protein in the phosphorylation of methyl alpha-glucoside by the complete PTS . The fluorescent label was shown to be predominantly, possibly exclusively, at the NH2-terminal methionine residue . The decay of the fluorescence intensity could be described in terms of a biexponential function with the time constants tau 1 approximately 7 ns, tau 2 approximately 15 ns, and a ratio of alpha 2/alpha 1 approximately 3 for the pre-exponential factors . The decay of the fluorescence emission anisotropy was found to be consistent with some internal motion of the probe, in addition to the rotation of the protein conjugate as a whole.

J Biol Chem, 1982 Dec 10, 257(23), 14499 - 509
Sugar transport by the bacterial phosphotransferase system . Primary structure and active site of a general phosphocarrier protein (HPr) from Salmonella typhimurium; Weigel N et al.; The general histidine-containing phosphocarrier protein (HPr) of the Salmonella phosphotransferase system is required for the phosphorylation of all sugar substrates by this system . The complete amino acid sequence of HPr, consisting of 84 amino acid residues, has been established . The sequence was determined by cleaving the protein with cyanogen bromide, trypsin, and with a protease from Staphylococcus aureus, followed by isolation and amino acid sequence determination of the resulting peptides . The Salmonella typhimurium protein contains two histidine residues, at positions 15 and 75, respectively . The phosphoryl group in phospho-HPr was linked to the His-15 residue . Based on several lines of evidence, the HPr protein from Escherichia coli appears to be identical with the protein from S . typhimurium . The HPr protein from S . aureus has also been isolated in this laboratory and was shown to differ from the HPr proteins described above both with respect to amino acid composition and the inability of the S . aureus and E . coli HPR proteins to substitute for each other in the in vitro sugar phosphorylation assays . The complete amino acid sequence of S . aureus HPr has been reported (Beyreuther, K., Raufuss, H., Schrecker, O., and Hengstenberg, W . (1977) Eur . J . Biochem . 75, 275-286), and its secondary structure has been predicted; this protein contains 70 amino acid residues and only one histidine . In the present studies, three methods were used to predict the secondary structure of S . typhimurium HPr, the results were combined, and a secondary structure for the protein is proposed . Although the amino acid compositions and sequences of the S . typhimurium and S . aureus HPr proteins are quite different, 13 residues are identical in the sequence of the two proteins, and most of these are located near the active site histidine residue . In addition, the predicted secondary structures of the two proteins are quite similar; the additional 14 residues in S . typhimurium, located at the carboxyl terminal end, are predicted to form an alpha-helix.

J Biol Chem, 1982 Dec 10, 257(23), 14492 - 8
Sugar transport by the bacterial phosphotransferase system . Isolation and characterization of a phosphocarrier protein HPr from wild type and mutants of Salmonella typhimurium; Beneski DA et al.; HPr, the histidine-containing phosphocarrier protein of the phosphotransferase system, has been isolated and purified from wild type Salmonella typhimurium and from two mutants of this organism . Comparison of the sequences of these three forms of HPr indicates that the two mutants contain substitutions at residue 4 in the polypeptide chain; in place of glutamine in the wild type, one mutant (SB3899) contained serine and the other (SB3093) contained lysine . The substitution of lysine for glutamine resulted in increased positive charge of the molecule which is reflected in an expected decreased mobility on polyacrylamide gel electrophoresis and its behavior on isoelectric focusing . However, these changes had no effect on phosphocarrier activity in the phoshoenolpyruvate:glycose phosphotransferase system as measured by the kinetics of the interaction on the mutant HPr proteins with both Enzyme I and Enzyme II . These results have important implications for potential chemical modification of HPr . The HPr from wild type cells was crystallized.

J Biol Chem, 1982 Dec 10, 257(23), 14477 - 91
Sugar transport by the bacterial phosphotransferase system . Phosphoryl transfer reactions catalyzed by enzyme I of Salmonella typhimurium; Weigel N et al.; The phosphorylation of Enzyme I is the first step in the phosphotransfer reaction sequence catalyzed by the phosphoenolpyruvate:glycose phosphotransferase system (PTS) from Salmonella typhimurium . The characterization of phospho approximately Enzyme I and the reactions in which it participates are described in this report . About 1 mol of phosphoryl group was incorporated per mol of Enzyme I monomer when the homogeneous enzyme was incubated with {32}phosphoenolpyruvate and Mg2+ . The phosphoryl group in phospho approximately Enzyme I is linked at the N-3 position in the imidazole ring of a histidine residue . Phospho approximately Enzyme I donates its phosphoryl group to pyruvate (to form phosphoenolpyruvate (P-enolpyruvate)) and to the histidine-containing phosphocarrier protein of the phosphotransferase system (HPr) (to form phospho approximately HPr) . In the presence of HPr and appropriate sugar-specific proteins, the phosphoryl group can be transferred from Enzyme I to methyl alpha-glucoside (to form sugar-phosphate) . The phosphorylation of Enzyme I by phosphoenolpyruvate requires divalent cation, but the phosphoryl group is transferred from phospho approximately Enzyme I to HPr in the presence of 20 mM EDTA . Kinetic studies show a biphasic rate for Enzyme I phosphorylation, suggesting that the enzyme is phosphorylated in the associated state . Equilibrium experiments were conducted on the following Reactions A and C . (formula: see text) . The apparent K' for Reaction B was calculated from K'A and K'C . K'C was found to be about 11 . K'A was studied both at very low and high substrate (P-enolpyruvate and pyruvate) concentrations relative to their respective Km values . At low substrate concentrations, the reaction appeared independent of pH in the range of 6.5 to 8.0, and when analyzed according to the simplest expression that could be written for total species of each component (Reaction A), the apparent average K' was 1.5 . At high substrate concentrations, about 50% of the Enzyme I was phosphorylated, and this value changed only slightly with large changes in the P-enolpyruvate to pyruvate ratio . Expressions for K'A are derived which partially explain these results by including enzyme-substrate complexes in the equilibrium expression . The K' values were used to derive apparent standard free energy changes for the hydrolysis of the phosphoproteins of the PTS . Since these are similar to those for the hydrolysis of P-enolpyruvate, the phosphate transfer potentials of the PTS phosphoproteins are among the highest of known biological phosphate derivatives . In addition, unlike the reactions which occur during anaerobic glycolysis and electron transport, the high phosphate transfer potential is conserved in the PTS reaction sequence until the last step, the translocation of the sugar substrate across the membrane concomitant with its phosphorylation . Potential regulation of the PTS, in particular the effect of the intracellular ratio of P-enolpyruvate to pyruvate, is considered.

J Biol Chem, 1982 Dec 10, 257(23), 14470 - 6
Sugar transport by the bacterial phosphotransferase system . Studies on the molecular weight and association of enzyme I; Kukuruzinska MA et al.; Studies were conducted on the physical properties of Enzyme I, the first protein in the Salmonella typhimurium phosphoenolpyruvate:glycose phosphotransferase system . Since values lower than those previously reported for the monomer molecular weight were obtained, experiments were performed to determine whether Enzyme I had been partially degraded during isolation of homogeneous protein . Crude extracts and partially purified and homogeneous protein preparations exhibited identical behavior in crossed immunoelectrophoresis analyses, indicating that the isolated protein represented native, intact Enzyme I . The monomeric subunit of Enzyme I is globular, with a frictional ratio of about 1 . Sedimentation equilibrium experiments provided a monomer molecular weight of 57,700 +/- 3,400, and gel filtration studies under denaturing conditions gave a comparable value of 57,000 . The values previously obtained from polyacrylamide gel electrophoresis analyses in the presence of sodium dodecyl sulfate varied with the conditions used, but under one set of conditions agreed with those given above . The sedimentation equilibrium studies were conducted at 8 degrees C, in the absence of substrates and cofactor (phosphoenolpyruvate, pyruvate, Mg2+) . Under these conditions Enzyme I self-associates, but the association is weak, favoring primarily monomer . Because of solubility limitations, the sedimentation experiments were performed with Enzyme I at an initial concentration of 0.5 mg/ml, providing a concentration distribution of 0.1 to 2 mg/ml . Computer analysis of the results showed that within this concentration range it was not possible to distinguish between two modes of self-association, monomer-dimer and isodesmic . The physiological significance of the results is discussed.

J Biol Chem, 1982 Dec 10, 257(23), 14543 - 52
Sugar transport by the bacterial phosphotransferase system . The glucose receptors of the Salmonella typhimurium phosphotransferase system; Stock JB et al.; We have previously reported that glucose can be phosphorylated by phospho-HPr and two sugar-specific pairs of proteins of the Escherichia coli and Salmonella typhimurium phosphoenolpyruvate:glycose phosphotransferase system . Each of the sugar-specific complexes comprises two proteins, lipid, and divalent cation, and each is present in membranes isolated from wild type cells . For reasons described in this report, one of the complexes is designated IIGlc and the other IIMan . The IIMan complex has previously been separated into its protein components, II-A and II-B (Kundig, W., and Roseman, S . (1971) J . Biol . Chem . 246, 1407-1418), while the accompanying reports describe dissociation of the IIGlc complex into its components, IIIGlc and II-BGlc . Curtis and Epstein (Curtis, S . J., and Epstein, W . (1975) J . Bacteriol . 122, 1189-1199) first showed that there are two phosphotransferase systems in whole cells responsible for glucose uptake and obtained the respective mutants, now designated ptsG and ptsM . The present studies provide kinetic conditions for assaying each activity separately (in vivo and in vitro), when both are present in the same membrane preparation . The IIGlc system is responsible for the uptake and phosphorylation of glucose and methyl alpha-glucoside, whereas the IIMan system is less specific and utilizes glucose, mannose, and 2-deoxyglucose . With high sugar concentrations in vitro, IIMan is also capable of phosphorylating methyl alpha-glucoside, fructose, and N-acetylmannosamine, while IIGlc phosphorylates fructose and mannose . The in vivo transport results were qualitatively consistent with the in vitro phosphorylation results, and several of the kinetic parameters also showed good quantitative agreement . The levels of the two activities depended on the growth conditions . In addition, transport studies showed that initial uptake rates of methyl alpha-glucoside and steady state levels of this analogue depended on the energy state of the cells and that these two parameters did not necessarily change in the same direction when metabolic inhibitors were used . A series of E . coli and S . typhimurium mutants were characterized both with respect to their ability to transport the glucose analogues and to phosphorylate them in vitro . The original mutants of Curtis and Epstein, ptsG and ptsM, were found to be defective in II-BGlc and the IIMan complex, respectively.

Infect Immun, 1982 Dec, 38(3), 948 - 52
Innate resistance of mice to Salmonella typhi infection; O'Brien AD; The basis for the natural resistance of mice to Salmonella typhi was examined . In contrast to Salmonella typhimurium, the virulence of S . typhi for mice was independent of the mouse strain and was not affected by inactivation of murine macrophages with silica . However, mice were more susceptible to S . typhi when given iron alone or iron and an iron chelator . The results suggest that the failure of S . typhi to undergo net growth in murine tissues reflects an inability of the bacterium to multiply rather than rapid killing by resident macrophages.

Environ Health Perspect, 1982 Dec, 46, 197 - 205
Mutagenic activity associated with by-products of drinking water disinfection by chlorine, chlorine dioxide, ozone and UV-irradiation; Zoeteman BC et al.; A retrospective epidemiological study in The Netherlands showed a statistical association between chlorination by-products in drinking water and cancer of the esophagus and stomach for males . A pilot-plant study with alternative disinfectants was carried out with stored water of the Rivers Rhine and Meuse . It was demonstrated that the increase of direct acting mutagens after treatment with chlorine dioxide is similar to the effect of chlorination . Ozonation of Rhine water reduced the mutagenic activity for Salmonella typhimurium TA 98 both with and without metabolic activation . UV alone hardly affects the mutagenicity of the stored river water for S . typh . TA 98 . In all studies, practically no mutagenic activity for S . typh . TA 100 was found . Although remarkable changes in the concentration of individual organic compounds are reported, the identity of the mutagens detected is yet unclear . Compounds of possible interest due to their removal by ozonation are 1,3,3-trimethyloxindole, dicyclopentadiene and several alkylquinolines . Compounds which might be responsible for the increased mutagenicity after chlorination are two brominated acetonitriles and tri(2-chlorethyl) phosphate . Furthermore, the concentration procedure with adsorption on XAD resin and the subsequent elution step may have affected the results . It is proposed to focus further research more on the less volatile by-products of disinfection than on the trihalomethanes.

Environ Health Perspect, 1982 Dec, 46, 111 - 6
Organic N-chloramines: chemistry and toxicology; Scully FE Jr et al.; The stability of aqueous solutions of organic N-chloramines, suspected of contaminating chlorinated water, has been studied . Two factors influence the decomposition of solutions of N-chloropiperidine and N-chlorodiethylamine: a spontaneous decomposition and photodecomposition . Since solutions of these compounds are relatively long-lived, a need for an analytical method for their identification is discussed . A new method is described which involves reaction of organic N-chloramines with arenesulfinic acid salts . The method gives high yields of stable arenesulfonamides . Several toxicological studies of N-chloropiperidine are described . The compound is mutagenic by Ames assay in Salmonella typhimurium strain TA 100 and does not require metabolic activation as indicated in a total body fluids analysis using C57BL/J6 mice . N-Chloropiperidine was subjected to a modified in vitro cell transformation assay using diploid fibroblast cells from Syrian hamster fetuses . A maximum number of foci of 4 per dish was observed at a seeding of 5 X 10(3) cells/60 mm dish . Under similar conditions, MNNG-induced foci ranged from 4 to 7 per dish.

J Am Geriatr Soc, 1982 Dec, 30(12), 769 - 73
Age-dependent differences in outcome of infections, with special reference to experiments in mice; Louria DB et al.; The host defects that increase either the frequency or the severity of certain infections in older persons are reviewed briefly . The major defect is in the functioning of the lymphocyte-macrophage system; this is expressed as deficits in cutaneous reactivity and T cell response after antigenic stimulation . A review of induced infections in experimental animals shows results generally consistent with the data in humans . Infections due to Listeria monocytogenes, Salmonella typhimurium, and Toxoplasma gondii all appear to be worse in senescent mice; each of these organisms is dealt with primarily by the lymphocyte-macrophage system . We have recently completed studies on aged mice infected with Staphylococcus aureus, an organism dealt with primarily by polymorphonuclear leukocytes rather than the lymphocyte-macrophage system . Surprisingly, staphylococcal infections were much worse in older animals . These studies suggest that in older mice there may also be a defect either in polymorphonuclear leukocyte mobilization and/or function or in the ability of older mice to resist the lethal effects of staphylococcal toxins.

Food Chem Toxicol, 1982 Dec, 20(6), 887 - 92
Inactivation of aflatoxin B1 mutagenicity by thiols; Friedman M et al.; The mutagenicity of aflatoxin B1 to Salmonella typhimurium strain TA98 decreased rapidly upon exposure of aflatoxin B1 to various thiols in aqueous solution . Mutagenic activity was reduced to control values within 24 hr with N-acetyl-L-cysteine (NAC), N-2-mercaptopropionylglycine (MPG), mercaptoethanol, reduced glutathione or mercaptopropionic acid at pH values near 4 . Mercaptoacetic acid, mercaptosuccinic acid, cysteine, acetyl-D,L-homocysteine thiolactone, cysteine methyl ester, D-penicillamine and beta-mercaptoethylamine were less effective . Relatively high thiol concentrations (greater than or equal to 0 . 25 M) were required to achieve complete inactivation within 24 hr with the thiols tested . The inactivation rate was strongly dependent on thiol concentration and pH, but was relatively independent of the aflatoxin concentration under the conditions examined . With MPG and NAC reaction rates were much slower at neutral pH values than at pH's between 3 and 4 . HPLC and thin-layer chromatographic examination of aflatoxin B1 solutions partially inactivated with NAC revealed the formation of a new product at a rate that correlated with the disappearance of aflatoxin B1 and the loss of mutagenic activity . This reaction product has not yet been identified, but the evidence suggests that it is the product of an addition of the thiol at the difuran region of the aflatoxin.

Mutat Res, 1982 Dec, 106(2), 195 - 208
Mutagenicity and cytotoxicity of the carcinogen-mutagen aflatoxin B1 in Streptococcus pneumoniae (Pneumococcus) and Salmonella typhimurium: dependence on DNA repair functions; Stark AA et al.; Strains R6, R6x and R6uvr-1 of Streptococcus pneumoniae (Pneumococcus) are sensitive to the cytotoxic effects of the mutagen/carcinogen aflatoxin B1 (AFB1) . R6uvr-1 is more prone to the cytotoxic effects of AFB1 than the repair-proficient parental strain, R6 . The same differential susceptibility of strains R6, R6x and R6uvr-1 was observed when UV light replaced metabolically activated AFB1 . All pneumococcal strains were immutable by AFB1 . AFB1 mutagenesis in Salmonella typhimurium strains was dependent on a functional RecA gene product . The enhancing effects of delta uvrB and plasmid pKM101 were found to be additive . Data presented are consistent with the following: (i) AFB1 toxic effects are due mainly to DNA binding of AFB1; (ii) AFB1 mutagenesis is dependent on error-prone DNA repair; (iii) Pneumococcus lacks an active error-prone (SOS) DNA-repair system.

Infect Immun, 1982 Dec, 38(3), 865 - 70
Enhanced phagocytic response of macrophages to bacteria by physical impact caused by bacterial motility or centrifugation; Tomita T et al.; The mechanism of enhanced phagocytic and chemiluminescent responses of macrophages caused by bacterial motility (T . Tomita, E . Blumenstock, and S . Kanegasaki, Infect . Immun . 32:1242, 1981) was studied . Both responses increased up to a certain level with an increased number of motile bacteria, such as Salmonella typhimurium, Escherichia coli, or Pseudomonas aeruginosa, added . In contrast, only a slight increase was observed with the motility (mot) mutants of these bacteria, even when 4,000 bacteria per single macrophage were added . If nonmotile bacteria were centrifuged together with a monolayer culture of macrophages, the number of bacteria ingested per macrophage increased dramatically . This phenomenon was not observed in the presence of cytochalasin B or at a low temperature, and about half of the associated bacteria were killed within 30 min of prolonged incubation, indicating that the bacteria were not simply embedded on the macrophage surface . An observed biphasic increase of ingestion with an increase in centrifugal force suggested the existence of a threshold velocity for efficient phagocytosis . The minimum centrifugal force required for maximal response was determined under the conditions in which equalized collision frequency between bacteria and macrophages was maintained when different centrifugal forces were employed . From the value obtained (5 x g), the required rate of movement was calculated as approximately 2.5 microns/s, supposing that the bacterium is spherical and has a 1-micron radius . This value is much lower than the velocity of movement of motile bacteria (20 to 50 microns/s) . The results indicate that physical impact caused by bacterial motility is enough to induce a high response of macrophages.

Zentralbl Bakteriol Mikrobiol Hyg {A}, 1982 Dec, 253(3), 344 - 54
The invasion of Salmonella typhimurium into the cecal wall of chickens infected with Eimeria tenella; Hikasa Y et al.; The effect of concurrent Eimeria tenella and Salmonella typhimurium infections on the invasion of S . typhimurium into the cecal wall of chickens were studied . In the experiment 1) groups were composed of birds infected with a daily dose of 1 X 10(3) to 1 X 10(5) S . typhimurium for 5 days and birds infected with S . typhimurium as the same manner one day after having been infected with 20,000 E . tenella oocysts . Chickens were killed 7, 10 and 14 days after coccidial infection . The ceca were examined bacteriologically . The number of S . typhimurium in the cecal washings and cecal wall and the number of chickens positive for S . typhimurium in the ceca were significantly greater in the concurrent infections than in the S . typhimurium alone . In experiment 2) groups were composed of birds infected with E . tenella and S . typhimurium in the same manner as experiment 1) and birds infected with 2 X 10(6) to 2 X 10(7) S . typhimurium for 5 consecutive days . Chickens were killed 7, 10 and 14 (or 15) days after coccidial infection . The distribution of S . typhimurium in the ceca was examined by fluorescent antibody technique . In coccidia-infected chickens, intense, specific fluorescence was noted in the epithelia destructed by coccidia, around the coccidial oocysts parasitized in the epithelial cells, and in the lamina propria and submucosa . In S . typhimurium alone-infected chickens, specific fluorescence was also found in the epithelia, lamina propria and submucosa, but was only limited in the lumen and on the surface of epithelial linings . The results indicated that the invasion of S . typhimurium into the cecal wall was enhanced by E . tenella infection in chickens.

Xenobiotica, 1982 Dec, 12(12), 831 - 48
Mutagenic properties of allylic and alpha, beta-unsaturated compounds: consideration of alkylating mechanisms; Eder E et al.; 1 . Allyl and allylic compounds may exert alkylating activities by SN1, SN2 and SN2' mechanisms . This direct alkylating potential can be determined quantitatively by a modified 4-NBP (4-nitrobenzyl pyridine) test . 2 . The alkylating activities in a systematically selected series of allyl and allylic compounds correlate well with the direct mutagenic potential as determined in the Ames test using Salmonella typhimurium TA 100 as tester strain . 3 . The allylic structure is a prerequisite for these types of activities since structurally related molecules lacking the allylic moiety are inactive in this respect . 4 . The potency of both the alkylating and mutagenic activity is determined by the strength of the leaving group: --OSO2CH3 greater than I greater than Br greater than Cl greater than--NCS . 5 . Indirect mutagenicity, through metabolic activation of the olefinic bond (by addition of S9 mix to the tester medium), can be ruled out for practically all compounds, the only exception found being 2,3-dichloro-1-propene where an increase of mutagenicity is encountered after addition of S9 mix; mechanistic explanations for this exception are provided . 6 . Analogous activation is demonstrated for benzyl halides, the alkylating potency of which is even higher than that of genuine allylic compounds . 7 . A variety of methyl- and chlorine-substituted allyl compounds has been included in the study: both groups increase activity, either by +I (CH3) or by +M effects (Cl) . 8 . alpha, beta-Unsaturated carbonyl compounds, e.g . acrolein and crotonaldehyde, also display direct mutagenic activity which is due to a completely different mechanism: covalent binding to nucleophilic sites of DNA bases by Michael addition . Methyl and other alkyl substitutions decrease the mutagenic potential in this type of compound . The corresponding alcohols, also displaying mutagenic activity but to a lesser degree, are metabolically activated by ADH (alcohol dehydrogenase) of the tester strain microbes to the aldehydes or ketones.

Rev Esp Fisiol, 1982 Dec, 38(4), 409 - 17
Isolation and kinetic properties of pyruvate kinase activated by fructose-1,6-biphosphate from Salmonella typhimurium LT-2.I; Garcia-Olalla C et al.; Pyruvate kinase, activated by fructose-1,6-biphosphate from Salmonella typhimurium LT-2, has been isolated and purified to homogeneity . The enzyme, similar to that from Escherichia coli, is a tetramer with an approximate molecular weight of 240,000 . The native enzyme shows optimum pH 6.8 (T = 30 degrees C) . The enzymatic reaction does not require K+ ions; while Mg2+ or Mn2+ are essential for its activity . The non-activated enzyme shows sigmoid kinetics to phosphoenolpyruvate with a Hill coefficient of 2.73; the activated enzyme becomes michaelian with KSADP y KSPEP 0.25 and 0.08 mM, respectively . Both substrates excess and ATP cause enzyme inhibition . In agreement with the experimental results a steady-state random-ordered hybrid Bi-Bi mechanism with two dead-end complexes is proposed.

Poult Sci, 1982 Dec, 61(12), 2517 - 9
Mutagenesis testing of acetyl-tributylcitrate and epoxidized soybean oil; Heath JL et al.; Mutagenesis testing was conducted on two plasticizers commonly used in plastic wrap manufacture, acetyl-tributylcitrate and epoxidized soybean oil . There is no record of mutagenic testing using a bacterial screening method for these two compounds . The two plasticizers were screened using mutant strains of Salmonella typhimurium . The tests determined that they were not mutagenic.

Food Chem Toxicol, 1982 Dec, 20(6), 917 - 20
Enzyme-mediated mutagenicity in Salmonella typhimurium of contaminants of synthetic indigo products; Jongen WM et al.; The mutagenic potential of two natural and seven synthetic, commercial indigo dye products was investigated . The natural products showed no mutagenicity in Salmonella typhimurium stains TA98 and TA100 . In the presence of rat-liver homogenate from Aroclor 1254 pretreated rats all of the synthetic products were mutagenic towards strain TA98 but not towards strain TA100 . The mutagenic effect produced was highly dependent on the amount of rat-liver homogenate added . Because of its high mutagenic potential, one product was further investigated . In the presence of rat-liver homogenate this product was weakly mutagenic towards strain TA1537 and strongly mutagenic towards strain TA1538 . No mutagenicity was observed in strain TA1535 . Experiments with purified synthetic indigo and natural indigo revealed that the mutagenic activity of the synthetic commercial products can be ascribed to one or more contaminants.

Zh Mikrobiol Epidemiol Immunobiol, 1982 Dec, (12), 60 - 5
{Incidence of antibiotic resistance in Salmonella typhimurium strains isolated in different epidemic situations}; Pokrovskii VI et al.; A total of 1800 S . typhimurium strains isolated in different regions of the USSR in 1968-1979 were studied . Of these strains, 68.6% were resistant to 6-8 antibiotics, 7.8% were resistant to 2-5 antibiotics, and 23.6% proved to be resistant to all antibiotics . The number of multiresistant strains sharply increased during the last 10 years . The strains isolated from different sources and in different epidemic situations considerably differed in their sensitivity to the action of antibiotics . The infective agents isolated from the hospital foci of salmonellosis were found to possess the maximum multiresistance . The study of the genetic nature of multiresistance showed that the multiresistance strains had a conjugative R-plasmid with resistance determinants CmTc, type Fin+, incompatibility group F1me . The phage typing of the strains with phages from the collection of the Tbilisi Research Institute for Vaccines and Sera revealed that these strains belonged to phagotype 2 . The problems of the relationship between the biological properties of causative agents and the character of the epidemic process of the diseases caused by these agents are discussed.

Mutat Res, 1982 Dec, 105(6), 387 - 92
Genotoxicity of flavoring agents; Kasamaki A et al.; The genotoxicity of 9 flavoring agents widely used in everyday foods was studied by a bacterial mutation test in the Salmonella/microsome system and by a chromosome test in Chinese hamster (CH) cells . In the mutation test none of the flavorings exhibited significant induction of his+ revertants in Salmonella typhimurium TA98 or TA100, either with or without rat-liver microsome as the metabolic activation system . On the other hand, in the chromosome test most of the agents induced severe chromosome aberration in the treated CH cells, suggesting a potential genotoxicity.

Mutat Res, 1982 Dec, 102(4), 393 - 400
Mutagenicity of a series of hexacoordinate cobalt(III) compounds; Schultz PN et al.; 15 cobalt(III) compounds have been tested for DNA-damaging capabilities using an E . coli differential repair assay and for mutagenicity in strains of Salmonella typhimurium . 4 of these compounds were active in both systems . Although the general ligand requirements for genetic activity of cobalt(III) appear to closely parallel those of chromium(III) and rhodium(III), the genetic activity of cobalt compounds seems particularly dependent upon the structure of the ligands coordinated about the metal ion . By a simple methyl substitution on the organic ligands, a compound completely devoid of activity, e.g . trans-{Co(pyr)4Cl2}Cl, could be made slightly mutagenic in Salmonella typhimurium strains e.g . trans-{Co(3-pic)4Cl2}Cl . Substitution at the 4-position rather than the 3-position on the same pyridine ring, e.g . trans-{Co(4-pic)4Cl2}Cl, results in a 50-fold enhancement of activity in both repair and mutagenesis systems . The difference in genetic activity is attributed to the influence of the ligands on the relative lability of the metal complex.

Mutat Res, 1982 Dec, 102(4), 373 - 81
Mutagenic action of methyl 2-cyanoacrylate vapor; Andersen M et al.; Alkyl 2-cyanoacrylate adhesives were tested for mutagenicity in Salmonella typhimurium strains TA98, TA100, TA1535 and TA1538 . Both a normal spot test and a spot test specially designed to test volatile compounds were used . The adhesives were also tested in the plate incorporation assay . These investigations showed that methyl 2-cyanoacrylate adhesives are mutagenic in strain TA100 . The spot test for volatile compounds showed that it is the vapors from the methyl 2-cyanoacrylate monomer that are responsible for the mutagenic effect . One can conclude that working with methyl 2-cyanoacrylate adhesives entails exposure to vapors with a mutagenic effect and may therefore pose a carcinogenic hazard . Because the adhesives are used in industry, their mutagenic effect has a special importance in work environment.

Mutat Res, 1982 Dec, 102(4), 331 - 46
Mutagenic studies on the hair dye 2-(2',4'-diaminophenoxy)ethanol with different genetic systems; Loprieno N et al.; A new hair-dye coupler, 2-(2',4'-diaminophenoxy)ethanol was analyzed for its potential mutagenic activity in different genotoxic assays, namely gene reverse mutations in Salmonella typhimurium, forward mutations in the yeast Schizosaccharomyces pombe, and in the V79 Chinese hamster cell line grown in vitro (HGPRT forward mutation system) . Two other genetic test systems, measuring the mitotic gene conversion in Saccharomyces cerevisiae (strain D4) and the unscheduled DNA-repair synthesis in a HeLa cell line grown in vitro, were also used . 2,4-Diaminoanisole, a mutagenic/carcinogenic structurally related hair-dye coupler, and a group of well-known mutagens, namely methyl methanesulfonate, ethyl methanesulfonate, cychlophosphamide, hycanthone and N-nitrosodimethylamine, were used as positive controls . The new aromatic amine, 2-(2',4'-diaminophenoxy)ethanol, was negative in all the assays performed, under the same treatment conditions as in the case of all the positive controls.

Mutat Res, 1982 Dec, 102(4), 319 - 29
Mutagenic evaluation of the hair-dye component 2,4-diaminophenoxyethanol in Salmonella typhimurium/microsome plate test and Saccharomyces cerevisiae strains D4 and XV185-14C; Shahin MM et al.; The hair-dye coupler 2,4-diaminophenoxyethanol was tested for mutagenicity in the histidine-requiring mutants of Salmonella typhimurium (TA1535, TA100, TA1537, TA1538 and TA98) . The tests were carried out in the absence and presence of uninduced as well as an Aroclor-1254-induced rat-liver microsomal activation system . In the absence and presence of uninduced S9 this compound was not mutagenic in all strains used . Negative results were also obtained in the presence of an Aroclor-1254-induced rat-liver microsomal activation system . The mutagenic activity of this compound was also investigated in 2 systems of yeast, the gene conversion system with strain D4 and the reversion system with strain XV185-14C . In the absence and presence of metabolic activation, no mutagenic effect was observed.

Mutat Res, 1982 Dec, 102(4), 313 - 8
Mutagenic activity of 2-(2',4'-diaminophenoxy)ethanol in strains TA1538 and TA98 of Salmonella typhimurium; Mohn G et al.; The mutagenicity of 2-(2',4'-diaminophenoxy)ethanol (2,4-DAPE) was compared with that of 2,4-diaminoanisole (2,4-DAA), a chemically related compound previously used in hair-dye formulations . Both chemicals were tested in standard procedures with the Salmonella/microsome mutagenicity test as described by Ames and colleagues . In several experiments, which extended over a total period of 2 years, 2,4-DAA exhibited definite, but variable mutagenicity toward strain TA1538 when S9 preparations of rat liver induced with Aroclor 1254 were present in the incubation mixtures . The compound 2,4-DAPE did not exhibit detectable mutagenic activity when tested concomitantly under the same experimental conditions . We conclude that 2,4-DAPE is not mutagenic for Salmonella under conditions of the standard mammalian microsome assay with strain TA1538 and TA98 as indicators.

Mutat Res, 1982 Dec, 97(6), 411 - 28
Phenotypic instability of Salmonella typhimurium tester strains: an example of a plasmid-enhanced genetic drift?
Anders M, Karpinsky GE, McCoy EC, Rosenkranz HS.
Strains derived from Salmonella typhimurium LT-2, which are used as tester strains in mutagenicity assays, show significant changes in biochemical phenotypes . The presence of plasmid pKM101 in these strains greatly increases both the frequency of these shifts as well as the spectrum of phenotypes involved . It is suggested that in plasmid-free strains these variations reflect the effects of endogeneously induced mutations which are amplified in the absence of a functional uvrB gene product . In plasmid-containing strains this genetic drift may be promoted further by the pKM101-coded error-prone DNA repair system . The observation of a plasmid-mediated genetic drift lends support to the suggestion that transposons may contribute to the carcinogenic process.

J Nutr, 1982 Dec, 112(12), 2333 - 41
Alterations in immune function in rats caused by dietary lipotrope deficiency: effect of age; Nauss KM et al.; Weanling male Sprague-Dawley rats were maintained on a control (C), folacin-deficient (F) or marginal methionine-choline diet (M/C) for 3 weeks, 3 months or 12 months . The immunocompetence of the animals was determined by in vivo (response to infection with salmonella typhimurium) and in vitro (lymphocyte transformation assay) methods . It was found that young animals were most sensitive to dietary lipotrope deficiency, and the in vivo response to bacterial infection did not always correlate with in vitro assessment of immune function . Histopathologic examination of spleens from S . typhimurium-infected rats maintained for 3 weeks on the experimental diets showed an overall decreased cellularity especially in the follicular areas, compared to controls . No differences were seen in the spleens of infected animals at later time points . A short-term (3-week) lipotrope deficiency resulted in a depressed lymphocyte transformation response to concanavalin A (Con A) in the spleen, thymus and lymph nodes; to phytohemagglutinin A (PHA) in the spleen and lymph nodes only . After 3 months on the F or M/C diets, a depressed Con A-induced transformation response was still seen in the spleen, but the normal aging-induced immunosuppression resulted in a low response in all animals, with few significant differences existing among groups.

J Bacteriol, 1982 Dec, 152(3), 1188 - 95
DNA primase of plasmid ColIb is involved in conjugal DnA synthesis in donor and recipient bacteria; Chatfield LK et al.; The sog gene of the IncI alpha group plasmid ColIb is known to encode a DNA primase that can substitute for defective host primase in dnaG mutants of Escherichia coli during discontinuous DNA replication . The biological significance of this enzyme was investigated by using sog mutants, constructed from a derivative of ColIb by in vivo recombination of previously defined mutations in a cloned sog gene . The resultant Sog- plasmids failed to specify detectable primase activity and were unable to suppress a dnaG lesion . These mutants were maintained stably in E . coli, implying that the enzyme is not involved in vegetative replication of ColIb . However, the Sog- plasmids were partially transfer deficient in E . coli and Salmonella typhimurium matings, consistent with the hypothesis that the normal physiological role of this enzyme is in conjugation . This was confirmed by measurements of conjugal DNA synthesis . Studies of recipient cells have indicated that plasmid primase is required to initiate efficient synthesis of DNA complementary to the transferred strand, with the protein being supplied by the donor parent and probably transmitted between the mating cells . Primase specified by the dnaG gene of the recipient can substitute partially for the mutant enzyme, thus providing an explanation for the partial transfer proficiency of the mutant plasmids . Conjugal DNA synthesis in dnaB donor cells was deficient in the absence of plasmid primase, implying that the enzyme also initiates synthesis of DNA to replace the transferred material.

Mutat Res, 1982 Dec, 102(4), 383 - 91
Sulfite suppresses the mutagenic property of coffee; Suwa Y et al.; The mutagenicity of instant and freshly brewed coffee on Salmonella typhimurium TA100 and TA98 without S9 mix was inactivated by sodium sulfite . Sulfite ion at a dose of 200 ppm almost completely inactivated the mutagenicity of coffee made in the ordinary way (5-15 mg dry weight/ml) . Sodium bisulfite and potassium metabisulfite had similar effects . On the contrary, L-ascorbic acid enhanced the mutagenicity of coffee . Sodium sulfite also inactivated the phage-inducing activity of coffee in inductest III . Sodium sulfite completely suppressed the mutagenicities of 1,2-dicarbonyls, namely diacetyl and glyoxal . Diacetyl is present in coffee, beer, butter and other foods and drinks . Because sodium sulfite, sodium bisulfite and potassium metabisulfite are widely used as food additives, they should be useful in reducing the levels of mutagens in foods.

J Bacteriol, 1982 Dec, 152(3), 1111 - 6
Nucleoside salvage pathway for NAD biosynthesis in Salmonella typhimurium; Liu G et al.; A previously undescribed nucleoside salvage pathway for NAD biosynthesis is defined in Salmonella typhimurium . Since neither nicotinamide nor nicotinic acid is an intermediate in this pathway, this second pyridine nucleotide salvage pathway is distinct from the classical Preiss-Handler pathway . The evidence indicates that the pathway is from nicotinamide ribonucleoside to nicotinamide mononucleotide (NMN) and then to nicotinic acid mononucleotide, followed by nicotinic acid adenine dinucleotide and NAD . The utilization of exogenous NMN for NAD biosynthesis has been reexamined, and in vivo evidence is provided that the intact NMN molecule traverses the membrane.

J Biol Chem, 1982 Nov 25, 257(22), 13726 - 30
Bacterial phosphotransferase system . Solubilization and purification of the glucose-specific enzyme II from membranes of Salmonella typhimurium; Erni B et al.; The glucose-specific enzyme II (IIGlc) of the phosphoenolpyruvate-dependent phosphotransferase system of Salmonella typhimurium has been purified to homogeneity . Purification included the following steps: detergent solubilization of membranes in polydisperse octyloligooxyethylene, isoelectrofocusing, chromatofocusing, and either glycerol gradient centrifugation or gel filtration, all in the presence of the same detergent . Enzymatic activity was assayed as phosphoenolpyruvate-dependent phosphorylation of methyl-alpha-D-glucopyranoside . It could be measured after detergent dilution only and required the presence of phosphatidylglycerol in a sonicated suspension . An antiserum prepared against enzyme IIGlc specifically inhibited phosphorylation of methyl-alpha-D-glucopyranoside . In the solubilized state, purified enzyme IIGlc exists as a complex of molecular weight of 105,000 and a sedimentation coefficient of 3.8 S . In polyacrylamide gels in sodium dodecyl sulfate, it has an apparent molecular weight of about 40,000.

Biochim Biophys Acta, 1982 Nov 24, 719(2), 273 - 83
Nitrogen fixation in Klebsiella pneumoniae during osmotic stress . Effect of exogenous proline or a proline overproducing plasmid; Le Rudulier D et al.; Osmotic stress, imposed by 0.5 M NaCl or other electrolytes and non-electrolytes, caused over a 100-fold reduction in the whole-cell nitrogen fixation activity of Klebsiella pneumoniae, wild-type strain M5A1 . This reduction of nitrogen fixation activity could be reversed by the addition of proline to the culture medium at 0.5 mM concentration . With 0.5 M NaCl, in the presence of proline, nitrogenase activity was 47-fold greater than in the absence of proline . A mutation, originally isolated in Salmonella typhimurium, which resulted in proline over-production and enhanced osmotolerance, was transferred into K . pneumoniae by F' conjugation . Intracellular proline, synthesized at high levels because of the mutation, had similar stimulatory effects on nitrogen fixation under osmotic stress as proline provided exogenously . In the overproducing strain, the cellular level of proline is elevated as much as 125-fold during stress over that seen in the control strain . To determine the mechanism of stimulation of nitrogen fixation by proline during stress, the biosynthesis of nitrogenase polypeptides was studied . Net nitrogenase biosynthesis and the biosynthesis of other unidentified peptides, is strongly inhibited during osmotic stress; proline reverses the inhibition . The role of proline in enhancing nitrogen fixation during osmotic stress is discussed.

Biochim Biophys Acta, 1982 Nov 24, 719(2), 251 - 8
Purification and some properties of cytosine deaminase from Salmonella typhimurium; West TP et al.; Cytosine deaminase (EC 3.5.4.1) from Salmonella typhimurium has been purified 419-fold to apparent homogeneity . SDS polyacrylamide gel electrophoresis indicated that the final cytosine deaminase preparation was homogeneous . The molecular weight of cytosine deaminase was determined to be approx . 230000 containing four identical subunits with each subunit having a molecular weight 54000 . Cytosine was deaminase has a pH optimum of 7.30 to 7.50 and a temperature optimum of 45 to 50 degrees C . Cytosine was deaminated specifically; 5-fluorocytosine was deaminated to a lesser extent . The Km and V values for cytosine were 0.74 mM and 47.16 mumole/min, respectively . As effectors of enzyme activity, PPi stimulated the deamination while metal ions and orotidine monophosphate inhibited it . The physical characteristics of cytosine deaminase lend credence to its proposed salvage role in pyrimidine metabolism as indicated previously by physiological studies (West, T.P . and O'Donovan, G.A., J . Bacteriol . (1982) 149, 1171-1174).

Clin Exp Immunol, 1982 Nov, 50(2), 283 - 90
Genetic control of resistance to Salmonella typhimurium infection in high and low antibody responder mice; Plant JE et al.; Mice selected by Biozzi for high and low responses to sheep erythrocytes were investigated for resistance to subcutaneous Salmonella typhimurium infection . The resistance was measured by LD50 values, viable bacterial counts in liver and spleen at 10 days, and the kinetics of infection over 4 weeks . High responder mice were susceptible to S . typhimurium injected subcutaneously (LD50 less than 10) and low line resistant (LD50 3 x 10(6)) . Control of natural resistance to S . typhimurium in inbred mice is primarily by a single gene . Ity, on chromosome 1 . Results with hybrid generations of Biozzi mice with either BALB/c (sensitive) or CBA (resistant) inbred mice indicated additional genetic control of resistance in Biozzi mice . Analysis of resistance data of backcrosses of (high x low)F1 with either parental strain showed this genetic control to be at least one other gene in the Biozzi mice, not linked to Ity . The antibody responses in the hybrid generations and inbred and Biozzi parental strains were tested by haemagglutination assays and ELISA . After specific stimulation of the mice there was an inverse relationship between resistance to S . typhimurium and antibody levels.

Immunol Lett, 1982 Nov, 5(5), 267 - 72
The protective capacity of immune sera in experimental mouse salmonellosis is mainly due to IgM antibodies; Saxen H et al.; Passive immunization was used to protect mice against a general infection caused by Salmonella typhimurium and our purpose was to compare the protective capacity of different immunoglobulin isotypes (classes and subclasses) . Three antisera were studied, one pool of mouse serum against the envelope of rough bacteria, and two rabbit sera against smooth bacteria . Three different methods were used to separate isotypes . The consistent finding was that only IgM antibodies protected efficiently . A unit of IgG antibodies had an effect that was 1/50th of the IgM effect or less . This effect could have been due to a contamination by IgM . IgA appears to be non-protective like IgG . In two of the antisera a considerable proportion of protective antibodies were against a defined antigenic determinant (anti-0-4,5 or anti-0-9) . IgG antibodies of these sera measured by the solid phase assay were also predominantly anti-0-4,5 or anti-0-9, respectively . This argues that the failure of IgG antibodies to protect cannot be explained by assuming that unlike IgM antibodies they are directed against "non-protective" determinants . We conclude that the observed difference between the protective capacities of IgM and IgG antibodies is due to C-region differences between the mu- and gamma-chains.

Eur J Cell Biol, 1982 Nov, 29(1), 1 - 12
Phagosomal-phagolysosomal membrane dynamics of stimulated mouse peritoneal macrophages; Leung KP et al.; Freeze-fracture replication was used to study the membrane events of stimulated mouse peritoneal macrophages during phagocytosis . An increase in intramembrane particles (IMPs) was observed on the protoplasmic fracture (PF) face of the freeze-fractured plasma membrane of phagocytosing macrophages as compared to those of the plasma membrane of nonphagocytosing cells . On the basis of freeze-fracture patterns of membranes, three types of phagosomal membranes were found following the ingestion of the streptomycin-dependent mutant (avirulent) of Salmonella typhimurium (SMD) . Most phagosomes 10 min after bacterial uptake had membranes that were structurally similar to the plasma membranes of phagocytosing cells . Structural transformations, i.e., changes in IMP number and size distribution, were observed in phagosomal membranes as the time from bacterial uptake increased . Similar types of phagosomal membranes were also found in phagocytosing macrophages when wild-type Salmonella typhimurium (virulent) was used as the phagocytic challenge . Some indirect morphological evidence suggested that membranes may be pinched off from the phagosomes-phagolysosomes which would be available for recycling back to the cell surface . In the systems studied thus far it appears that the freeze-fracture structure of phagolysosomal membranes is significantly different from that of the plasma membranes . In addition, freeze-fracture evidence suggested that fusion can take place between adjacent phagosomes or phagolysosomes.

Can J Physiol Pharmacol, 1982 Nov, 60(11), 1367 - 73
Superoxide dismutase protects against paraquat-mediated dioxygen toxicity and mutagenicity: studies in Salmonella typhimurium; Hassan HM et al.; Paraquat is univalently reduced to the relatively stable, but oxygen-sensitive, paraquat radical (PQ.+) . This PQ.+ can react with dioxygen to generate the superoxide radical, which can further generate other more deleterious species of oxygen free radicals (i.e., hydroxyl radical, OH.) . These oxygen free radicals are known to cause chromosomal breaks; therefore, it was logical to postulate that paraquat is a mutagen . This proved to be the case when tested in a modified Ames test using a liquid incubation assay . Salmonella typhimurium strains TA98 and TA100 were grown in the presence of various concentrations of PQ, as well as in the presence of known mutagenic compounds: mitomycin C, azide, and proflavine . Paraquat was much more toxic and mutagenic in a simple nutritionally restricted medium than in a rich complex medium and these toxic and mutagenic effects were oxygen dependent . Furthermore, cells containing high levels of superoxide dismutase were more resistant to the toxic and mutagenic effects of paraquat than were cells containing a normal level of this enzyme.

Appl Environ Microbiol, 1982 Nov, 44(5), 1110 - 7
Membrane lipid alterations and thermal stress in Salmonella typhimurium 7136; Tomlins RI et al.; Salmonella typhimurium ATCC 7136 exhibited major changes in lipid composition when grown in the presence of either 0.15% sodium deoxycholate or 0.15% sodium benzoate . These lipophilic compounds had directly opposing effects on the lipid profile of the organism . The saturated/unsaturated ratio was markedly elevated in benzoate-grown cells . On the other hand, it was depressed by an even greater margin from the control after growth in the presence of deoxycholate . Adjustments in the phospholipid content of the cells were also recorded . Phosphatidylethanolamines decreased by 28 and 50% in the deoxycholate- and benzoate-grown cells, respectively . Compensatory increases in phosphatidylglycerols of 87.5 and 175% occurred, along with increases in cardiolipins of 12- and 22-fold, respectively . Deoxycholate or benzoate supplementation also altered the relative distribution of neutral lipids; again, benzoate stimulated the greater change . Compositional changes were accompanied in the organism by increased heat sensitivity, but the effect on the susceptibility of S . typhimurium to injury varied with the physical properties of the supplement used.

Appl Environ Microbiol, 1982 Nov, 44(5), 1081 - 5
Rapid identification of microorganisms by circular-intensity differential scattering; Salzman GC et al.; There is a pressing need in clinical medicine for rapid identification of microorganisms . We describe a method that has the potential for such rapid identification: circular-intensity differential scattering, which is based on the differential scattering of left and right circularly polarized light . The scanning time required to obtain the spectral signature of an organism is about 4 min . Using a commercial circular dichrograph modified to measure circular intensity differential scattering at 90 degrees, we obtained significantly different spectra for five different crude influenza viruses . Salmonella typhimurium TA98 and TA100, and Escherichia coli HB101, HB101(pBR322), and HB101(pMB9) . Purified supercoiled plasmid pBR322 DNA was readily distinguishable from linear pBR322 DNA; such differences in nucleic acid packaging may be significant factors in the discriminatory power of this technique.

J Urol, 1982 Nov, 128(5), 1104 - 8
Immunotherapy of murine transitional cell carcinoma; Lamm DL et al.; A series of 6 controlled experiments in C3H/He mice were performed to evaluate nonspecific immunotherapeutic regimens with a transplantable murine bladder tumor (MBT2) . Immunotherapeutic agents studied included live Bacillus Calmette-Guerin (BCG) preparations in varying doses and strains (Tice, Pasteur, and Glaxo), Re mutant glycolipid (ReG) from Salmonella typhimurium, BCG cell wall skeletons (CWS), CWS plus B4 glycolipid fraction of ReG, and Keyhole-Limpet Hemocyanin (KLH) . Animals received an intradermal MBT2 inoculation and were then randomized to treatment and control (saline treated) groups . Immunotherapy was administered intralesionally 1 day after tumor transplantation . Tumors were excised by amputation at a volume of 400 mm . and animals were later rechallenged with tumor inocula, again treated, and followed for tumor incidence growth rate and survival . No antitumor affect was observed with ReG, CWS or CWS plus B4 . KLH immunotherapy did result in measurable antitumor effect . Consistent and statistically significant (p less than 0.01) antitumor responses as measured by prolonged survival and decreased growth rate were observed with Tice and Pasteur strains of BCG in doses ranging from 5 X 10(5) to 1 X 10(7) colony forming units per animal . Doses in excess of 10(7) units were found to decrease antitumor response . Glaxo strain BCG had no beneficial effect when used in the maximal dose (10(6) colony forming units) that could be administered . In animals immunized with intermediate doses of live Tice or Pasteur strain BCG in the study, effective long term immunity to transitional cell carcinoma was observed . Although many new immunotherapeutic agents have been advocated in other tumor models, to date we have found Tice and Pasteur strains of live BCG to be the most effective agents in the treatment of transitional cell carcinoma.

Environ Health Perspect, 1982 Nov, 45, 35 - 40
Phthalate esters as peroxisome proliferator carcinogens; Warren JR et al.; The phthalate ester di(2-ethylhexyl) phthalate is both a peroxisome proliferator and a hepatic carcinogen . Peroxisome proliferators as a class are hepatocarcinogenic in rodent species . However, none of the peroxisome proliferators tested to date including the phthalate esters and related alcohol and acid analogs have demonstrated mutagenic or DNA-damaging activity in the in vitro Salmonella typhimurium/microsomal or the lymphocyte 3H-thymidine assays . A working hypothesis is proposed that peroxisome proliferation itself initiates neoplastic transformation of hepatic parenchymal cells by increasing intracellular rates of DNA-damaging reactive oxygen production . Evidence which supports such a hypothesis includes increased fatty acid beta-oxidation, elevated H2O2 levels, accumulation of peroxidized lipofuscin, disproportionately small increase in catalase, and elevated peroxisomal uricase activity which accompany peroxisome proliferation in hepatocytes . Direct testing of this hypothesis will provide insight into mechanisms of phthalate ester carcinogenicity and cytotoxicity.

Environ Health Perspect, 1982 Nov, 45, 111 - 4
Mutagenic activity of phthalate esters in bacterial liquid suspension assays; Seed JL; The mutagenic activities of several phthalate esters have been evaluated in an 8-azaguanine resistance assay in Salmonella typhimurium . Three phthalate esters were found to be mutagenic: dimethyl phthalate, diethyl phthalate and di-n-butyl phthalate . A number of other phthalate esters were not found to be mutagenic, including di(2-ethylhexyl) phthalate, di-n-octyl phthalate, diallyl phthalate, diisobutyl phthalate and diisodecyl phthalate . A metabolite of di(2-ethylhexyl) phthalate, 2-ethylhexanol, was also noted to be mutagenic . The mutagenic activity of this agent and others in this series was dose dependent but weak . No dose-response curve exceeded more than 3.5 times background at maximally testable concentrations . A liquid suspension histidine reversion assay of dimethyl phthalate showed levels of mutagenic activity similar to that observed in the azaguanine resistance assay . The data suggest a need for further investigation of the mutagenic potential of these agents in other assay systems.

J Bacteriol, 1982 Nov, 152(2), 959 - 62
Bacteriophage P22 as a vector for Mu mutagenesis in Salmonella typhimurium: isolation of nad-lac and pnc-lac gene fusions; Holley EA et al.; Salmonella phage P22 was utilized as a vector for phage Mu cts d1(Apr lac) mutagenesis in Salmonella typhimurium . Efficient transposition of phage Mu d1 and the construction of gene fusions were readily accomplished with this procedure . Mutants blocked in the biosynthesis of NAD+ and in pyridine nucleotide cycle metabolism were isolated by this method, resulting in nadB-lac, nadC-lac, and pncB-lac gene fusions.

Antimicrob Agents Chemother, 1982 Nov, 22(5), 775 - 80
Diffusion of beta-lactam antibiotics through liposome membranes containing purified porins; Kobayashi Y et al.; A method to determine the diffusion of cephalosporins through porin pores in vitro was developed, using liposomes reconstituted from phospholipids, lipopolysaccharides, and purified porin trimers . With this method, the roles of several species of porin pores from Escherichia coli and Salmonella typhimurium in the diffusion of cephalexin, cephaloridine, and cephalothin were examined . Results clearly showed that porins from E . coli B and 39,000-molecular-weight porins from S . typhimurium formed the most efficient pores . Thus, these were considered to represent a single functional group . OmpF and OmpE porins of E . coli K-12 and 38,000-molecular-weight porins of S . typhimurium formed moderately efficient pores . OmpC porins of E . coli K-12 and 40,000-molecular-weight porins of S . typhimurium were the least efficient pore formers . The present method can be used to distinguish the role of individual porin pores in the diffusion of cephalosporins.

Infect Immun, 1982 Nov, 38(2), 588 - 91
In vitro effect of murine-derived transfer factor on Salmonella-specific rosette formation; Smith RA et al.; The splenic lymphocytes from Salmonella-immune ICR Swiss or C3H/HeJ mice formed greater than 0.2% antigen-specific rosettes with sheep erythrocytes coated with a spent-medium protein antigen of Salmonella typhimurium . These rosette-forming lymphocytes were found to be sensitive to the effects of antithymocyte serum plus complement . Transfer factor prepared from the Salmonella-immune splenic lymphocytes of ICR Swiss mice was active in sensitizing nonimmune ICR Swiss or C3H/HeJ lymphocytes to form greater than or equal to 0.2% rosettes with salmonella antigen-coated sheep erythrocytes . These rosettes were also sensitive to antithymocyte serum and complement . Few rosettes were formed between the transfer factor-treated lymphocytes and sheep erythrocytes coated with a Listeria protein antigen . A nonimmune dialysate preparation was inactive in sensitizing nonimmune lymphocytes, as indicated by a lack of rosette formation . Neither the immune transfer factor nor the nonimmune dialysate had any enhancing or abrogating effect upon rosette formation by splenic lymphocytes from Salmonella-immune mice . The enumeration of antigen-specific rosettes may be a useful means of assaying for transfer factor activity.

J Gen Microbiol, 1982 Nov, 128 (Pt 11), 2797 - 804
Phages I alpha and I2-2: IncI plasmid-dependent bacteriophages; Coetzee JN et al.; Phage I alpha was isolated from sewage from Windhoek, South West Africa . It formed relatively clear plaques about 2 mm in diameter, on sensitive strains of Escherichia coli K12 and Salmonella typhimurium LT2 . The phage had an hexagonal outline with a diameter of about 24 nm, contained RNA and was resistant to chloroform . Phage I alpha formed plaques or propagated only on organisms carrying I1 plasmids or the I gamma plasmid R621a . The efficiency of plating was higher on E . coli than on S . typhimurium hosts . The phage adsorbed along the length of shafts of I1 pili . Phage I2-2 was isolated from Pretoria sewage . It was a filamentous virus and individual virions varied considerably in length . Phage I2-2 formed turbid plaques which varied from pin point to about 1 mm in diameter on all hosts . It was resistant to RNAase and sensitive to chloroform . Phage I2-2 had a spectrum of activity limited to strains harbouring I2 plasmids but the adsorption site could not be demonstrated . The phage was not related serologically to phages Ifl or PR64FS.

Infect Immun, 1982 Nov, 38(2), 476 - 86
Association of adhesive, invasive, and virulent phenotypes of Salmonella typhimurium with autonomous 60-megadalton plasmids; Jones GW et al.; The plasmid DNA content of six invasive and adhesive strains of Salmonella typhimurium was determined, and all six strains (CR8500 {S850}, CR6600 {TML}, W118, NY, PR, and S2204) were found to harbor at least one plasmid equivalent in size to the 60-megadalton plasmid ("cryptic" plasmid), pSLT, which is normally resident in S . typhimurium strain LT2 . The role of such 60-megadalton plasmids in the adhesive and invasive properties of strain CR6600, a commonly encountered salmonella pathogen that produces type 1 fimbriae, and strain CR8500, a representative FIRN biotype which does not produce type 1 fimbriae, was studied further by obtaining derivatives of these strains that no longer harbored an autonomous 60-megadalton plasmid . Strains CR6260 and CR6190 and strains CR8100 and CR8353, which were "cured" derivatives of strains CR6600 and CR8500, respectively, were significantly less adhesive and invasive in the HeLa cell test . A 53.5-megadalton colicin plasmid harbored by strain CR6600 did not detectably influence these properties . Additionally, strain CR6260 was avirulent, and strain CR8100 was 1,000 to 10,000-fold less virulent for orally infected mice as compared with their respective parental strains . Significantly, the virulence of strain CR8100 correlated with tissue colonization by bacteria that exhibited autonomous copies of a 60-megadalton plasmid . We propose that this plasmid exists in both autonomous and integrated states and that the in vivo environment selects for bacteria with autonomous plasmid copies which can express the virulent phenotype, thus enabling such strains to survive the defense mechanisms of the host.

J Biol Chem, 1982 Oct 10, 257(19), 11368 - 76
Metabolism and activation of 7,8-dihydrobenzo{a}pyrene during prostaglandin biosynthesis . Intermediacy of a bay-region epoxide; Reed GA et al.; A Tween 20-solubilized preparation of prostaglandin endoperoxide synthase has been shown to metabolize 7,8-dihydrobenzo{a}pyrene (H2BP) to a form highly mutagenic to Salmonella typhimurium strain TA98 . The arachidonic acid-dependent metabolism of H2BP by microsomal and purified prostaglandin endoperoxide synthase has been studied and the products identified . A spectral investigation of the metabolism indicated the bay-region double bond as the primary site of metabolism . Radiolabeled H2BP was synthesized and incubated with the enzyme preparations and the metabolites were separated by reverse phase high performance liquid chromatography and quantitated by liquid scintillation counting . Radioactive products were characterized by co-chromatography with chemically synthesized standards, UV-visible spectra, and mass spectrometry of acetate derivatives . The major polar products were determined to be trans- and cis-9,10-dihydroxy-7,8,9,10-tetrahydrobenzo{a}pyrene and 7,8,9,10-tetrahydrobenzo{a}pyrene-9-one in a ratio of 1:1.2:0.4 . The inclusion of 5 mM 3,3,3-trichloropropene-1,2-oxide, an epoxide hydrolase inhibitor, produced the same products but in a ratio of 1:2.3:1.2 . Incubations with purified prostaglandin endoperoxide synthase yielded the three products in a ratio of 1:2.8:0.7 . The major nonpolar product was identified as benzo{a}pyrene . The polar products of metabolism, the effects of 3,3,3-trichloropropene-1,2-oxide on their distribution, and the detection of a mutagenic intermediate support the conclusion that H2BP is co-oxygenated during prostaglandin biosynthesis to 9,10-epoxy-7,8,9,10-tetrahydrobenzo{a}pyrene.

J Biol Chem, 1982 Oct 10, 257(19), 11808 - 15
Purification and structural determination of nontoxic lipid A obtained from the lipopolysaccharide of Salmonella typhimurium; Qureshi N et al.; Endotoxin extracted from the heptose-less mutant of Salmonella typhimurium was hydrolyzed in 0.1 N HCl in methanol/water (1:1, v/v) at 100 degrees C to yield lipid A, which was then fractionated on a Sephadex LH-20 column to yield a major monophosphoryl lipid A fraction . The monophosphoryl lipid A was further fractionated by preparative thin layer chromatography . This process yielded three major bands (TLC-1, -3, and -5) and two minor bands (TLC-7 and -9) . The purity of these fractions was established by ion exchange and reverse phase high performance liquid chromatography . The thin layer fractions were analyzed by fast atom bombardment mass spectrometry . TLC-1 and -3 gave molecular ions (M-H)- at m/e 1730 and 1716, respectively . Both of these fractions contained beta-hydroxymyristic, lauric, and 3-myristoxymyristic acids in O-acyl linkages . The molecular formula and Mr of TLC-1 are C95H179O22N2P and 1731.16; those of TLC-3 are C94H177O22N2P and 1717.15 . TLC-1 was a methyl homolog of TLC-3 . The major component of TLC-5 (C80H151O22N2P and Mr = 1506.99) gave a molecular ion at m/e 1506 and contained two beta-hydroxymyristic acids and a lauric acid in the O-acyl linkages . The major component of TLC-7 (C66H125O19N2P and Mr = 1280.83) and the single component of TLC-9 gave molecular ions at m/e 1280 and 1098, respectively . TLC-7 contained lauric and beta-hydroxymyristic acids in the O-acyl linkages . TLC-9 (C54H103O18N2P and Mr = 1098.69) contained a single O-acylated beta-hydroxymyristate group . TLC-1 and -3 were nontoxic in the chick embryo lethality test and regressed established tumors in the syngeneic guinea pigs.

Appl Environ Microbiol, 1982 Oct, 44(4), 825 - 31
Accessory replicons of species of Salmonella and Shigella; Dhillon TS et al.; Shigella and Salmonella strains isolated from clinical samples were examined . Out of 42 Shigella strains tested, 17 (40%) were found to be colicinogenic and another 3 were lysogenic . All three lysogens yielded a phage antigenically homologous to coliphage P2 . Out of 30 strains tested, only 1 was found to be resistant to both neomycin and sulfamethoxazole . Out of 48 strains of Salmonella tested for drug resistance, only 2 showed multiple drug resistance . In contrast to Shigella isolates, the Salmonella isolates were infrequently (approximately 5%) bacteriocinogenic . The frequency of lysogeny in Salmonella strains was found to be 6% when tested on Salmonella typhimurium LT2, but by using a set of five indicators belonging to species Salmonella potsdam, Salmonella mbadanka, Salmonella dublin, Salmonella london, and Salmonella wandsworth, 50% of the strains were shown to be lysogenic . Salmonella phages related to P22 were recoverable from Salmonella saintpaul, Salmonella indiana, and Salmonella heidelberg . Some isolates of S . typhimurium yielded a temperature-sensitive and P22-heterologous phage which was found to be a more efficient transducer of bacterial genetic markers than P22 . EcoRI-generated fragments of the DNA of some phages permitted the establishment of a clonal descent for some of the wild-type lysogenic bacterial strains . This last observation points out the potential usefulness of prophages as epidemiological markers.

J Pharmacol Exp Ther, 1982 Oct, 223(1), 163 - 8
Studies on microsomal cytochrome P-450, monooxygenases and epoxide hydrolase in cultured keratinocytes and intact epidermis from BALB/C mice; Bickers DR et al.; Studies of drug and carcinogen metabolism in cultured keratinocytes and in intact epidermis from the skin of BALB/C mice were performed . The cultured cells were shown to retain 33 to 40% of corresponding intact epidermal aryl hydrocarbon hydroxylase (AHH), 7-ethoxycoumarin-O-de-ethylase (7-ED) and epoxide hydrolase activities . In vitro treatment of the cells or in vivo application to the skin of animals with the polycyclic aromatic hydrocarbons benz(a)anthracene (BA) or benzo(a)pyrene resulted in significant induction of AHH and 7-ED activities . The responsiveness of AHH was greater than that of 7-ED in both preparations . BA (4 x 10(-4) M) induced AHH and 7-ED at least 12- and 4-fold, respectively, in either the keratinocytes or intact epidermis, whereas epoxide hydrolase activity was not altered in either preparation . All of these enzyme activities were predominantly located in the microsomal fraction of the keratinocytes and the epidermis . Keratinocyte AHH had a pH optimum at 7.4 . The apparent Km for benzo(a)pyrene as substrate in control and BA-induced cells was 10 and 6 microM, respectively, whereas Vmax was 15-fold greater in the carcinogen-treated cells . CO-difference spectra demonstrated the presence of the heme-protein cytochrome P-450 in microsomes prepared from keratinocytes and intact epidermis; absorption maximum was between 451 to 453 nm . The metabolic activity of keratinocytes was further demonstrated in the Ames mutagen assay . A supernatant (9000 x g) prepared from keratinocytes pretreated with BA enhanced the mutagenesis of 2-aminoanthracene in the TA98 strain of Salmonella typhimurium . These studies indicate that cultured keratinocytes provide a useful experimental model system for the study of epidermal drug and carcinogen metabolism.

Proc Natl Acad Sci U S A, 1982 Oct, 79(19), 6093 - 7
Role of prostaglandin D2 in the hypothermia of rats caused by bacterial lipopolysaccharide; Ueno R et al.; The intraperitoneal administration of lipopolysaccharide from Salmonella typhimurium (1 mg/kg) caused a fall in the rat colonic temperature of about 2 degrees C at an ambient temperature of 22 +/- 3 degrees C . The hypothermia induced by the lipopolysaccharide was abated in a dose-dependent manner by the administration of indomethacin . Other inhibitors of prostaglandin synthetase such as aspirin, flufenamic acid, and phenylbutazone had effects similar to those of indomethacin . When various prostaglandins were injected intracerebroventricularly, only prostaglandin D2 caused a dose-dependent fall in the colonic temperature at doses between 1.2 and 6 nmol/kg . Microinjection of prostaglandin D2 into the preoptic area caused hypothermia of about 1 degree C . However, injection of prostaglandin D2 into the posterior hypothalamus had little effect on the colonic temperature . The hypothermia caused by prostaglandin D2 was not abated by the administration of indomethacin . The amount of prostaglandin D2 increased significantly in the preoptic/hypothalamic region of rat brain 1 hr after the intraperitoneal administration of the lipopolysaccharide, whereas such increase was not observed in rats pretreated with indomethacin . The in vitro incubation of the preoptic/hypothalamic slices with the lipopolysaccharide also increased the amount of prostaglandin D2 . These results suggest that the intraperitoneal administration of the lipopolysaccharide induces the release of prostaglandin D2 in the preoptic/hypothalamic area of rat brain and that the latter compound is involved in the hypothermic response of rats to the lipopolysaccharide.

Food Chem Toxicol, 1982 Oct, 20(5), 531 - 3
Formation of mutagens in boiled pork extract; Lin JY et al.; When boiled pork extract was heated under reflux at 102 degrees C for 4 hr mutagens, which were detected using Salmonella typhimurium strains TA98 and TA1538, were formed . The level of mutagenicity was dependent on the concentration of pork in the extract, the duration of boiling and on pH; the optimum pH for mutagen formation was found to be 9 to 11 . Thin-layer chromatographic analysis showed that the mutagens formed in boiled pork extract were chromatographically distinguishable from benzo{a}pyrene and from the primary mutagenic pyrolysis products of tryptophan (3-amino-1,4-dimethyl-5H-pyrido{4,3-b}indole and of glutamic acid (2-amino-6-methyldipyrido{1,2-a:3',2'-d}imidazole).

Gann, 1982 Oct, 73(5), 681 - 3
Mutagenicity of methylglyoxal in coffee; Kasai H et al.; Major carbonyl compounds from a extract of ground roasted coffee beans were identified as 5-hydroxymethylfurfural, acetol, glyoxal, methylglyoxal and diacetyl . Among these carbonyl compounds, methylglyoxal showed considerable mutagenic activity toward Salmonella typhimurium TA100 without S9 mix (around 100,000 revertants/mg) . More than 50% of the total mutagenic activity of coffee can be accounted for by the activity of methylglyoxal.

Chem Biol Interact, 1982 Oct, 42(1), 97 - 105
DNA binding and growth inhibitory properties of a series of 2,7-di-alkyl-substituted derivatives of proflavine; Baguley BC et al.; Proflavine (3,6-diaminoacridine) and its 2,7-dimethyl, 2,7-diethyl, 2,7-diisopropyl and 2,7 di-t-butyl derivatives have been compared with respect to their DNA binding and biological properties . The binding of the first three members of the series to covalently closed circular duplex DNA showed the unwinding properties expected of intercalators . The 2,7-diisopropyl showed intermediate properties and the 2,7-di-t-butyl derivative failed to unwind this DNA . Antibacterial toxicity, measured in cultures of Salmonella typhimurium, increased with increasing lipophilic character of the compounds . Mutagenicity in the TA1537 frameshift tester strain was restricted to the first two members of the series, although the mutagenicity of the more lipophilic members may have been masked by toxicity . In contrast, toxicity towards cultures of L1210 cells showed a possible transition between intercalating and non-intercalating derivatives . It is proposed that DNA intercalation provides the major component of the toxicity towards cultured leukaemia cells, whereas lipophilicity provides the major component towards bacteria.

Antimicrob Agents Chemother, 1982 Oct, 22(4), 541 - 7
Thiolutin-resistant mutants of Salmonella typhimurium; Joshi A et al.; Spontaneous mutants of Salmonella typhimurium isolated in our laboratory from thiolutin-containing tryptone agar plates are partially resistant to thiolutin in enriched media . In minimal media, they are not resistant . The mutants are not temperature sensitive but fail to support the development of phage P22 at higher temperatures (40 degrees C) . Thiolutin did not interfere with RNA polymerase or nucleotide kinase in in vitro experiments . However, thiolutin did inhibit the rate of incorporation of exogenous uridine into the cellular pool and consequently the acid-precipitable material . It appears that one site of action of thiolutin is at the membrane level.

Zentralbl Bakteriol Mikrobiol Hyg {A}, 1982 Oct, 253(1), 88 - 101
Proteins from Salmonella R-mutants mediating protection against Salmonella typhimurium infection in mice I . Preparation of proteins free from lipopolysaccharide using various chromatographic methods; Bhatnagar N et al.; Different chromatographic methods are described to remove traces of LPS from proteins extracted from the surface of several R-mutants of Salmonella . The protein preparations obtained by these methods were found to contain less than 0.001% of beta-hydroxymyristic acid as determined by gas liquid chromatography . This corresponds to less than 0.003 to 0.006% of R-form-LPS (depending on the chemotype of the mutant) and less than 0.014% of S-form-LPS . From some protein mixtures LPS could be removed by repeated gel filtration on a column of Sepharose CL-6B . Recycling gel filtration proved to be more effective considering the high recovery of protein in much shorter time . Ion exchange chromatography on DEAE Sepharose CL-6B was also useful in some cases . Thus, using one or the other method LPS free protein preparations could be obtained with extracts obtained from 6 out of 7 bacterial strains.

Appl Environ Microbiol, 1982 Oct, 44(4), 801 - 8
Mutagenicity and toxicity of carcinogenic and other hydrazine derivatives: correlation between toxic potency in animals and toxic potency in Salmonella typhimurium TA1538; Malca-Mor L et al.; Eleven hydrazine derivatives and an aromatic amine were examined for mutagenicity and toxicity to Salmonella typhimurium . Phenylhydrazine, 2-nitrophenylhydrazine, 4-nitrophenylhydrazine, 2,4-dinitrophenylhydrazine, p-tolylhydrazine, and 4-nitroaniline were found to be frameshift mutagens (strain TA1538) . Benzylhydrazine, m-hydroxybenzylhydrazine, p-hydrazinobenzoic acid, L-tyrosine hydrazide, p-aminobenzoyl hydrazide, and isoniazid were not mutagenic . All chemicals were toxic to strain TA1538 . A qualitative correlation was found between the pK of the compounds and their mutagenicity . Relative toxicities of hydrazines to bacteria were found to be closely correlated with the relative toxicities of the same compounds in animals . Described herein is a methodology for the rapid prescreening of chemicals which may be used as drugs for those with a high benefit/risk ratio.

Mutat Res, 1982 Oct-Nov, 102(3), 201 - 12
The aza-arenes as mutagens for Salmonella typhimurium; Seixas GM et al.; Several unsubstituted aza-arenes have been found to be more mutagenic to Salmonella typhimurium than their corresponding parent hydrocarbons . In most cases, the activity of these compounds depended on the presence of a post-mitochondrial supernatant for metabolic activation, although acridine was mutagenic only in the absence of such an activating system . An examination of the effect of the metabolizing system's concentration on mutagenicity showed that quinoline, benzo{f}quinoline, and phenanthridine have different optima . In an attempt to uncover active intermediates in aza-arene metabolism, N-oxides of quinoline and phenanthridine were synthesized and found to be non-mutagenic, and coincubation with the epoxide hydrase inhibitor trichloropropylene oxide did not affect the mutagenic activity of quinoline or phenanthridine.

Food Chem Toxicol, 1982 Oct, 20(5), 557 - 61
Bacterial mutagenicity studies on chloroform in vitro; Van Abbe NJ et al.; Chloroform was tested for mutagenicity in the Salmonella/microsome assay using five strains of Salmonella typhimurium . In view of previous reports describing the development of liver and kidney tumours in some experiments involving long-term administration of chloroform to rats and mice, the mutagenicity tests were carried out in the absence of any S-9 microsomal-enzyme preparation and in the presence of S-9 microsomal-enzyme preparations derived from (a) livers and (b) kidneys of rats and mice previously exposed to the microsomal-enzyme inducer Aroclor 1254 . No evidence of potential mutagenicity was observed under any of the test conditions . To determine whether the findings might have been influenced by the volatility of the chloroform, the test organisms were exposed to chloroform vapour, but again chloroform gave no indication of potential mutagenicity . Taken in conjunction with already published data from mutagenicity studies with chloroform, it appears unlikely that the tumours observed in some long-term rodent studies are attributable to a genotoxic action of the compound.

Cell, 1982 Oct, 30(3), 893 - 902
Evidence for posttranslational translocation of beta-lactamase across the bacterial inner membrane; Koshland D et al.; Secretion of beta-lactamase was studied in Salmonella typhimurium infected with P22 phage carrying wild-type and mutant alleles of the structural gene . Cellular location of precursor and mature products of wild-type and temperature-sensitive and chain-terminating mutants was analyzed by cell fractionation and by trypsin accessibility in intact and lysed spheroplasts . The precursors of wild-type and all these mutants (none of which alter the signal peptide) are found sequestered within the cell, while all the mature forms have at least partially been translocated across the inner membrane . Thus most beta-lactamase molecules traverse the membrane after completion of their translation . It seems that the carboxyl terminus of beta-lactamase is not required for translocation across the inner membrane but is required for the protein to appear in the periplasm as a soluble species.

Mutat Res, 1982 Oct, 105(4), 211 - 21
Microbial mutation studies with tetrachlorvinphos (Gardona)); Brooks TM et al.; The mutagenic activity of tetrachlorvinphos was investigated in agar-layer cultures of Escherichia coli WP2 and WP2 uvrA, Salmonella typhimurium TA1535, TA1538, TA98 and TA100 . Assays were carried out both in the presence and in the absence of S9 fractions of liver homogenates from rats and mice, both from untreated animals, and from animals pre-treated with Aroclor 1254 . The induction of mitotic gene conversion by tetrachlorvinphos was studied in stationary phase cultures of the yeast Saccharomyces cerevisiae D4 . No mutagenic effects, as determined by reverse gene mutation, were detected in vitro in the bacterial/mammalian microsome assay when a range of bacterial tester strains were exposed to tetrachlorvinphos at amounts up to 2000 micrograms per plate, either in the absence or in the presence of S9 fractions from non-induced or Aroclor-induced mouse or rat livers . Tetrachlorvinphos did not increase the mitotic gene conversion frequency in stationary phase cultures of the yeast, Saccharomyces cerevisiae D4.

J Bacteriol, 1982 Oct, 152(1), 260 - 8
Genetic mapping of mutations in a highly radiation-resistant mutant of Salmonella typhimurium LT2; Ibe SN et al.; The genes involved in the high radiation resistance of mutant R68 of Salmonella typhimurium LT2 were mapped by conjugation . It was observed that the high radiation resistance involved genes localized in two regions of the chromosome, which have been designated as garA and garB for high gamma resistance . The garA gene mapped near gal and uvrB at about 18 map units, and the garB gene mapped near purC at about 49 map units . The resistance of R68 was reduced to the wild-type level by the acquisition of the two wild-type alleles, garA+ and garB+ . Recombinants carrying the garA or garB gene repaired single-strand breaks in their DNA faster than did the wild-type strain . However, only those with the garA mutation showed a marked increase in UV irradiation resistance above the wild-type level, whereas those with garB mutation exhibited an increased rate of spontaneous degradation of DNA beyond the level observed in recA cells.

Zh Mikrobiol Epidemiol Immunobiol, 1982 Oct, (10), 79 - 81
{Changes in the cAMP level in macrophages in Salmonella typhimurium phagocytosis}; Boichenko MN et al.; The effect of a virulent S . typhimurium strain and its cAMP-deficients mutant on the level of cAMP in macrophages in the process of phagocytosis has been studied . The virulent strain has been shown to induce the 3-fold increase of the level of cAMP in macrophages, while the mutant renders no such effect.

Cell, 1982 Oct, 30(3), 903 - 14
Diverse effects of mutations in the signal sequence on the secretion of beta-lactamase in Salmonella typhimurium; Koshland D et al.; Mutations in the beta-lactamase structural gene that alter the signal peptide were used to study secretion into the periplasm of Salmonella typhimurium . Processing and cellular location of mutant gene products were followed by pulse-chase and cell-fractionation experiments and by trypsin accessibility in intact and lysed spheroplasts . The precursor proteins examined never appear as a free species in the periplasm . Two of the signal-sequence mutants accumulate a precursor form that is trypsin-accessible in intact spheroplasts; the precursors synthesized by the remaining mutants resemble wild-type in that they remain trypsin-inaccessible . One of the latter mutants does produce mature protein, but at a very reduced rate . It thus appears that signal-sequence mutations can affect more than one step in the secretion process, and that processing of the signal peptide is not required for the protein to be translocated (at least partially) across the inner membrane.

J Bacteriol, 1982 Oct, 152(1), 49 - 56
Regulatory region of the Klebsiella aerogenes tryptophan operon; Blumenberg M et al.; The trp operon of Klebsiella aerogenes was cloned, and its regulatory region was sequenced . Comparison with previously reported trp regulatory sequences of other enteric bacteria indicates that the K . aerogenes trp promoter-operator region is most similar to the corresponding region of Salmonella typhimurium . The trp leader regions of K . aerogenes and other enteric bacteria are organized similarly, but there are significant differences in the stabilities of the predicted secondary structures in their leader transcripts . These differences should make the K . aerogenes attenuator a weaker transcription termination site than any of the other attenuator regions studied; this was confirmed in in vitro transcription experiments . The sequence of the leader transcript and the precise site of in vitro termination were determined.

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