Avian Dis, 1995 Jan-Mar, 39(1), 1 - 8 Mitogenic responses of the head-associated lymphoid tissues of the chicken; Maslak DM et al.; A blastogenesis microassay employing 3-(4,5-dimethylthiazol-2-yl)-2,5 diphenyl tetrazolium bromide (MTT) was adapted to measure blastogenic responses of lymphocytes from the chicken's head-associated lymphoid tissues (i.e., the harderian gland and conjunctiva-associated lymphoid tissue) to T- and B-cell mitogens . Lymphocytes isolated from peripheral blood, spleen, and the harderian gland had highly significant (P < 0.01) responses to T- and B-cell mitogens compared with control lymphocytes cultured without mitogens . Cultured lymphocytes obtained from the harderian gland had highly significant mitogenic responses to the T-cell mitogen concanavalin A (25 to 100 micrograms/ml) and to the B-cell mitogen Salmonella typhimurium lipopolysaccharide (1.25 to 5.0 micrograms/ml) compared with the control lymphocytes . Mitogenic responses of cultured lymphocytes obtained from the conjunctiva-associated lymphoid tissue could not be measured within the given parameters of the blastogenesis microassay . This was primarily due to the low yield of lymphocytes, which proved to be a limiting factor . The ability of the MTT blastogenesis microassay to detect blastogenic responses of the harderian gland to mitogens may be indicative of its usefulness for measuring cell-mediated immunity responses to other antigens. Microbiol Immunol, 1995, 39(2), 95 - 103 Different sensitivity of complement to Salmonella typhimurium accounts for the difference in natural resistance to murine typhoid between A/J and C57BL/6 mice; Nakano A et al.; The difference in natural resistance to Salmonella typhimurium between S . typhimurium-resistant A/J mice and S . typhimurium-susceptible C57BL/6 mice was analyzed . In both strains, the growth of S . typhimurium was controlled in the spleen until 48 hr of infection, while serum C3b levels were increased in A/J mice immediately after infection but not in C57BL/6 mice . Incubation of A/J mouse serum with S . typhimurium or its lipopolysaccharide (LPS) generated sufficient amounts of C3b, but that of C57BL/6 mouse serum with them did not . A/J macrophages had higher intracellular killing activity in vitro than did C57BL/6 cells against S . typhimurium pre-opsonized with each corresponding fresh serum . However, the cells from both mice exhibited a similar level of killing activity against S . typhimurium pre-opsonized with fresh A/J serum or rabbit complement . The resistance of C57BL/6 mice was significantly increased by opsonizing S . typhimurium with fresh A/J serum or rabbit complement before inoculation . The serum level of interferon-gamma (IFN-gamma) in A/J mice was 2.7 times as high as in C57BL/6 mice at 48 hr post-infection . Recombinant murine IFN-gamma enhanced the intracellular killing activity of macrophages from both mice when S . typhimurium was pre-opsonized with fresh A/J serum but not with fresh C57BL/6 serum . These findings suggest that A/J macrophages exhibit maximal killing activity against A/J serum-opsonized S . typhimurium in vivo when the cells are activated with IFN-gamma . Therefore, the rapid and sufficient activation of complement by Salmonella LPS may render A/J mice more resistant against murine typhoid. Biosci Biotechnol Biochem, 1995 Jan, 59(1), 31 - 4 Purification and characterization of cycloinulooligosaccharide fructanotransferase (CFTase) from Bacillus circulans MCI-2554; Kushibe S et al.; Cycloinulooligosaccharide fructanotransferase (CFTase) that produces cyclofructan from inulin was purified about 69-fold from a culture broth of Bacillus circulans MCI-2554 by column chromatographies on DEAE-Toyopearl, QAE-Toyopearl, hydroxyapatite, and phenyl-Sepharose . The molecular mass of the enzyme was estimated to be 115 kDa by SDS-polyacrylamide gel electrophoresis and gel filtration, indicating a monomer structure . Maximal activity was observed at pH 7.5 and 45 degrees C . The enzyme was active from pH 5.5 to pH 9.5, and at temperatures up to 45 degrees C . The enzyme activity was inhibited by Fe2+ and Cu2+ . A part of the amino acid sequence was identical with that of beta-fructofuranosidases of Zymomonas mobilis, carrot, Salmonella typhimurium, and mung bean. Plasmid, 1995 Jan, 33(1), 27 - 39 The host range of RK2 minimal replicon copy-up mutants is limited by species-specific differences in the maximum tolerable copy number; Haugan K et al.; The minimal replicon of the broad-host-range plasmid RK2 consists of a gene, trfA (trans-acting replication), encoding a protein required for initiation of plasmid replication . The TrfA protein binds to iterons in the cis-acting origin of vegetative replication (oriV), but the exact mechanism by which TrfA-mediated replication initiation takes place is not known . We report here the isolation and characterization of five mini RK2 trfA mutant plasmids with an elevated plasmid copy number, four in Pseudomonas aeruginosa and one in Azotobacter vinelandii . The mutations are localized between or downstream of previously reported Escherichia coli copy-up mutations in trfA, and one of the mutations has been described earlier as an independent copy-up isolate in E . coli . The five mutant plasmids were all moderately copy up in both E . coli and their host of origin, in spite of the use of isolation procedures which were expected to select efficiently in favor of plasmid mutants specifying high copy numbers . In contrast, previously described high copy-up mutants isolated in E . coli could not be established in P . aeruginosa and A . vinelandii . These high copy-up mutants were shown to induce cell killing in E . coli under conditions where the plasmid copy number was increased as a physiological response to reduced growth rate . We propose that the reason for this killing effect is that the copy number under these conditions exceeds an upper tolerance level specific for E . coli . By assuming that the corresponding tolerance level is lower in P . aeruginosa and A . vinelandii than in E . coli, and that the mechanism of copy number regulation is similar, the model can explain the phenotypes of all tested copy up mutants in these two hosts . Analogous studies were also performed in Salmonella typhimurium and Acetobacter xylinum . The data obtained in these studies indicate that the above model is probably generally true for gram-negative bacteria, and the results also indicate that the maximum tolerable copy number is surprisingly low in some hosts. Mol Microbiol, 1995 Jan, 15(1), 25 - 38 Functional analysis of the Salmonella typhimurium invasion genes invl and invJ and identification of a target of the protein secretion apparatus encoded in the inv locus; Collazo CM et al.; We have carried out a functional analysis of invl and invJ, two Salmonella typhimurium genes required for this organism to gain access to cultured mammalian cells . These genes are located immediately down-stream of invC, a previously identified gene also required for bacterial invasion . Non-polar mutations in either of these genes rendered S . typhimurium severely defective for entry into cultured epithelial cells, although these mutations did not affect the ability of these organisms to attach to those cells . Nucleotide sequence analysis revealed that the invl and invJ genes encode proteins with molecular weights of 18,077 and 36,415, respectively . Polypeptides of similar sizes were observed when these genes were expressed in a bacteriophage T7 RNA polymerase-based expression system . Comparison of the predicted sequences of invl and invJ with translated sequences in the existing databases indicated that these proteins are identical to the previously identified S . typhimurium SpaM and SpaN proteins . Further analysis of these sequences revealed regions of homology between Invl and the N-terminus of IpaB of Shigella spp . and between InvJ and EaeB of enteropathogenic Escherichia coli . Localization studies by immunoblot analysis indicated that InvJ is secreted to the culture supernatant, a surprising finding since this protein also lacks a typical signal sequence . Mutations in invG and invC, two members of the Salmonella inv locus, effectively prevented the transport of InvJ to the culture supernatant . Thus, InvJ is the first identified target of the protein secretion apparatus encoded in the inv locus and therefore a candidate to have effector functions related to bacterial entry. J Am Vet Med Assoc, 1995 Jan 1, 206(1), 75 - 6 Septicemic salmonellosis in two llamas; Anderson NV et al.; At necropsy, Salmonella choleraesuis var kunzendorf was recovered from the lungs of a 6-year-old female llama that died within a few days of onset of illness . The llama had had fence-line contact with 40 sows at a farm . Salmonella typhimurium was isolated from a blood sample of a 6-day-old male cria that also died after a short illness. J Reprod Immunol, 1995 Jan, 28(1), 15 - 30 In vivo inhibition of cell-mediated and humoral immune responses to cellular antigens by SV-IV, a major protein secreted from the rat seminal vesicle epithelium; Romano-Carratelli C et al.; Microgram amounts of protein SV-IV, a major secretory protein produced by adult rat seminal vesicle epithelium, markedly decrease the mouse humoral immune response to cellular xenogeneic or allogeneic antigens (sheep red blood cells (SRBC) or mouse epididymal spermatozoa) . The significant reduction in the total number of splenocytes and their main cell subsets in SRBC-immunized mice, the dramatic decrease in the number of Ia+ splenic T cells and the marked inhibition of splenocyte ability to respond in vitro to polyclonal mitogen stimuli suggest that the macrophage accessory cells are the primary target of the SV-IV immunosuppressive activity in vivo . Moreover, the infection of SV-IV-treated mice with Salmonella typhimurium produced an increased mortality of the experimental animals associated with a marked decrease of the phagocytic and intracellular killing activities of their peritoneal macrophages. Biol Pharm Bull, 1995 Jan, 18(1), 49 - 52 Activation of N-nitrosodialkylamines to mutagens by a metalloporphyrin/oxidant model system for cytochrome P450; Okochi E et al.; N-Nitrosodialkylamines are environmental alkylating carcinogens which are metabolically activated to alpha-hydroxy nitrosamines by cytochrome P450 . The precise mechanism of their activation is not well understood, and a simplified chemical model for cytochrome P450 as a non-enzymatic system is useful for investigating the mechanism . In the present study, a chemical model was used in a bacterial mutation assay as a substitute of S9 mix, and its ability in the activation of N-nitrosodialkylamines was elucidated . In the presence of tetrakis(pentafluorophenyl)porphyrinatoiron(III) chloride and tert-butyl hydroperoxide, the mutagenicity of N-nitrosodialkylamines {alkyl = methyl (NDM), ethyl (NDE), propyl (NDP) and butyl (NDB)} in Salmonella typhimurium YG7108 was detected . The mutagenicity increased by the pre-incubation and was dependent on the concentration of mutagens . The mutagenic activity of N-nitrosodialkylamines in Salmonella typhimurium YG7108 was in the following order: NDB > NDM > NDE approximately NDP . The formation of aldehydes derived from dealkylation in the present model was exemplified by the formation of acetaldehyde from NDE . These results showed that N-nitrosodialkylamines were activated by the model system, and consequent mutagenicity was observed . The oxidation by the model can mimic the metabolic activation of chemical carcinogens by cytochrome P450, and the biomimetic catalyst is useful in investigating the mechanisms of the metabolic pathway of N-nitrosodialkylamines. Vet Med (Praha), 1995, 40(1), 29 - 32 {Characteristics of the plasmid profile of inositol- and rhamnose- negative strains of Salmonella typhimurium}; Cizek A et al.; S . typhimurium isolates obtained during a large outbreak of human salmonellosis associated with smoked mackerels in the Czech Republic as well as strains of S . typhimurium isolated from black headed gull (Larus ridibundus) were examined following biotyping, phage typing, plasmid profiling and restriction endonuclease analysis (Eco RI, Hind III and Bam HI) of plasmid DNA . The epidemic strain of S . typhimurium and two isolates from environment of nesting colony black-headed gull were meso-inositol and L-rhamnose negative, phage type 141 . The isolates from human and environment of nesting colony were found to share the same plasmid profile and REA. Int J Food Microbiol, 1995 Jan, 24(3), 385 - 96 Growth and penetration of Salmonella enteritidis, Salmonella heidelberg and Salmonella typhimurium in eggs; Schoeni JL et al.; Eggs and egg dishes are important vehicles for Salmonella infections . Salmonella enteritidis, Salmonella typhimurium and Salmonella heidelberg, which can be isolated from chicken ovaries and feces, have been implicated in approximately 50% of the foodborne salmonellosis outbreaks in the United States . In this study, the growth of these three organisms, inoculated into yolks and albumen, was compared at 4, 10 and 25 degrees C . Regardless of whether 10(2) cfu/g or 10(4) cfu/g was inoculated into the yolk or albumen, populations of all strains increased 3 logs or more in number in one day when incubated at 25 degrees C . Maximum numbers of Salmonella ranged from 10(8) to 10(10) cfu/g . All strains grew at 10 degrees C, but peak numbers were lower and occurred later than those at 25 degrees C . Populations of the three Salmonella strains inoculated into eggs stored at 4 degrees C grew sporadically; in some test groups populations declined . The potential for Salmonella in contaminated feces to establish in the interior of eggs was examined by monitoring shell penetration . At 25 degrees C, all three Salmonella strains penetrated the shell in 3 days, but at 4 degrees C, only S . typhimurium was found in one membrane sample . When hatchery conditions were simulated by incubating eggs at 35 degrees C for 30 min followed by storage at 4 degrees C, penetration was enhanced . Penetration was observed by day 1-3 when eggs were exposed to 10(4) cfu Salmonella/g feces . Increasing the inoculum to 10(6) cfu/g feces resulted in 50-75% of the contents of eggs to be contaminated by day 1 . All Salmonella-positive samples were detected by enrichment . Results of this study indicate that S . enteritidis, S . typhimurium, or S . heidelberg present in feces can penetrate to the interior of eggs and grow during storage. J Clin Microbiol, 1995 Jan, 33(1), 173 - 9 Value of plasmid profiling, ribotyping, and detection of IS200 for tracing avian isolates of Salmonella typhimurium and S . enteritidis; Millemann Y et al.; Seventy selected strains of Salmonella typhimurium and S . enteritidis isolated from related poultry flocks in three independent geographical areas were characterized by phenotypic and genotypic methods to compare the usefulness of the methods in epidemiological studies . The 56 S . typhimurium isolates were poorly discriminated by their biotypes, resistance patterns, and plasmid profiles . Nine different ribotypes were obtained after DNA digestion by BglII, PvuII, and SmaI . Seven IS200 types, characterized by six to nine copies of IS200 on the chromosome, were detected after digestion of genomic DNA by PstI . These studies resulted in the definition of 15 clonal lineages distributed in three clusters . The 14 S . enteritidis strains were not discriminated either by ribotyping or by detection of IS200 (IS200 typing), but were separated on the basis of antibiotic resistance and plasmid profiling . The stability of the insertion sequence type was confirmed by inoculation of an S . typhimurium strain to axenic chickens reared for 15 weeks in sterile isolators. Environ Mol Mutagen, 1995, 26(1), 86 - 93 Role of classical nitroreductase and O-acetyltransferase on the mutagenicity of nifurtimox and eight derivatives in Salmonella typhimurium; Jurado J et al.; This study investigates the mutagenicity of nifurtimox (NFX) and eight analogues in Salmonella typhimurium indicator strains that possess different levels of classical nitroreductase or O-acetyltransferase activities . The NFX analogues tested replace the 3-methyl-4-yl-tetrahydro-1,4-thiazine-1,1-dioxide group of the parent compound with the following other groups: indazol-1-yl (1G); pyrazol-1-yl (1B); benzimidazol-1-yl (1E); 1,2,4-triazol-4-yl (1D); 1-methyl-3-methylthio-1,2,4-triazol-4-yl-5-thione (1I); 3,5-bis(methylthio)-1,2,4-triazol-4-yl (1H); 1-adamantyl (ADA); and 4,6-diphenylpyridin-1-yl-2-one (1K) . In the genetic backgrounds of the standard Ames tester strains TA98 and TA100, these bacteria combine the L-arabinose resistance forward mutation assay (Ara test) with a deficiency or overproduction of either nitroreduction or O-acetylation . The Ara test revealed, in agreement with previous findings, important differences between TA98 and TA100 and demonstrated, moreover, that these genetic differences are of significance in mutagenicity testing with nitrofuran compounds . The Ara test also indicated dissimilarities between the metabolic activation of NFX and its analogues, these compounds being classified in three different groups according to their mutagenicity toward strain BA14 (genetic background of TA98) and its derivatives . The first group included analogues (1G, 1E, 1I, and ADA) that showed similar mutagenic potency in all bacterial strains . These compounds are considered not to be substrates for both classical nitroreductase and O-acetyltransferase . The second group included compounds (analogues 1B and 1K, and the reference drug NFX) with increased mutagenicity toward the strain overproducing the classical nitroreductase, and/or reduced mutagenicity toward the corresponding deficient bacteria . These compounds are considered to be activated by the classical nitroreductase . The third group (analogues 1D and 1H) was activated by bacterial O-acetyltransferase, and consequently showed increased and decreased mutagenicity with the particular overproducer or deficient bacterial strain, as compared to their isogenic parentals . Previous reports have pointed out interest in NFX analogue 1H as a promising candidate for the replacement of NFX . The present study further enhances the putative interest of compound 1H, based on the different metabolic activation pathway exhibited by this analogue as compared to the parental drug, NFX. Int J Occup Med Environ Health, 1995, 8(1), 41 - 7 Non-mutagenicity of thiadiazole-1,3,4 derivatives in Salmonella typhimurium strains; Kalski A et al.; The Ames mutagenicity assay with Salmonella typhimurium strains (TA97a, TA98, TA100 and TA102) was used to investigate the ability of five dyes (thiadiazole-1,3,4 derivatives) to induce point mutations . The results did not reveal any mutagenic effects of the tested dyes on the S . typhimurium strains . No mutagenic activity was observed in the experimental series with and without exogenous activation. Acta Vet Hung, 1995, 43(1), 95 - 103 The production of K88 antigen by Escherichia coli and Salmonella typhimurium strains with recombinant DNA; Holoda E et al.; Expression of K88ab antigen by strains with recombinant DNA, differing in molecular weight or promoter, was subjected to investigation . Strains with recombinant DNA produced greater amounts of antigen than did field isolates . Maximal production was recorded for the E . coli C600 strain with 10.85 kb recombinant DNA with promoter P1 of the pBR322 vector . The substitution of promoter Ptac for promoter P1 did not result in an increased expression of K88ab antigen . The production of K88ab antigen by Salmonella typhimurium TM333 with recombinant DNA was on a level comparable to that of E . coli C600 or E . coli HB101 strains with the same recombinant DNA. Nippon Saikingaku Zasshi, 1995, 50(2), 537 - 45 {Incidence and serotypes of Salmonella in apparently healthy swine at slaughterhouses in Japan: 1975-1989}; Yoshida T et al.; To find healthy Salmonella carriers among swine, isolation of Salmonella from fresh cecum samples was attempted at slaughterhouses in Tokyo, Saitama, and Tochigi during a period of 11 years . Of a total 3,058 samples, 1,341 were collected between 1975 and 1979, and the other 1,717 between 1984 and 1989 . The overall isolation rate of Salmonella was 13.3% (408 pigs) . The rate was 23.1% between 1975 and 1979 and 5.7% between 1984 and 1989 . A total of 1,037 isolates were identified as Salmonella and classified into 28 serotypes . These serotypes involved Salmonella typhimurium (26.1%), S . derby (25.4%), and S . london (9.5%) . However, the detection rate of these serotypes varied from year to year . Two serotypes were detected from each of 37 pigs and three from a pig . Of these 38 pigs, 27 carried the serotypes of S . typhimurium or S . derby or both . The present study revealed that Salmonella carriers were highly frequent among healthy swine in Japan in 1970s, but decreased in 1980s. DNA Seq, 1995, 5(3), 145 - 52 Nucleotide sequence of the region between crr and cysM in Salmonella typhimurium: five novel ORFs including one encoding a putative transcriptional regulator of the phosphotransferase system; Titgemeyer F et al.; A 4471 bp region between crr and cysM on the Salmonella typhimurium chromosome (49.5 min) has been sequenced . Five ORFs were found within this region, one of which is likely to be the putative regulatory gene, ptsJ, that corresponds in map position to a gene which when mutated allows expression of a cryptic Enzyme I of the phosphotransferase system . The deduced amino acid sequence of the encoded protein is similar to those of several open reading frames (ORFs) including ORFT2 of Rhodobacter spheroides with which it is 28% identical throughout most of its length (comparison score of 21 S.D.) . PtsJ exhibits a putative, N-terminal, helix-turn-helix, DNA binding domain that is similar in sequence to those in members of the GntR family of transcriptional regulators . Analyses of the sequences of the ORFs encoded within this region are presented. Environ Mol Mutagen, 1995, 25(4), 284 - 7 Mutagenicity in vitro of 3,4-dichloro-5-hydroxy-2(5H)-furanone (mucochloric acid), a chlorine disinfection by-product in drinking water; Jansson K et al.; The mutagenicity of chlorinated humic drinking waters is accounted for mainly by a single contaminant, 3-chloro-4-(dichloromethyl)-5-hydroxy-2(5H)-furanone (MX), as assessed in Salmonella typhimurium strain TA100 . In the present study 3,4-dichloro-5-hydroxy-2(5H)-furanone (mucochloric acid, MA), another drinking water contaminant much less potent as a mutagen in TA100 than MX, was tested in Chinese hamster ovary (CHO) cells for the induction of mutation at the hypoxanthine phosphoribosyl transferase (hprt) locus to 6-thioguanine resistance (TGr) . Unexpectedly, MA induced TGr mutants in CHO cells with a potency comparable to that reported previously for MX . In subsequent experiments with S . typhimurium, the presence of pKM101 plasmid in strain TA100 increased susceptibility to the mutagenicity of MA, but much less than to that of MX, relative to the parental strain TA1535 lacking pKM101 . The difference between the two compounds in TA100 thus appears to be due to a higher enhancement of the mutagenicity of MX than that of MA by pKM101 mediated error-prone DNA repair. Pharmacogenetics, 1995, 5 Spec No, S103 - 7 Conjugation of carcinogens by theta class glutathione s-transferases: mechanisms and relevance to variations in human risk; Guengerich FP et al.; Conjugation of chemicals with glutathione (GSH) can lead to decreased or increased toxicity . A genetic deficiency in the GSH S-transferase mu class gene M1 has been hypothesized to lead to greater risk of lung cancer in smokers . Recently a gene deletion polymorphism involving the human theta enzyme T1 has been described: the enzyme is present in erythrocytes and can be readily assayed . A rat theta class enzyme, 5-5, has structural and catalytic similarity and the protein was expressed in the Salmonella typhimurium tester strain TA1535 . Expression of the cDNA vector increased the mutagenicity of ethylene dibromide and several methylene dihalides . Mutations resulting from the known GSH S-transferase substrate 1,2-epoxy-3-(4'nitrophenoxy)propane were decreased in the presence of the transferase . Expression of transferase 5-5 increased mutations when 1,2,3,4-diepoxybutane (butadiene diepoxide), 4-bromo-1,2-epoxybutane, or 1,3-dichloracetone were added . The latter compound is a model for the putative 1,2-dibromo-3-chloropropane oxidation product 1-bromo-3-chloroacetone . These genotoxicity and genotyping assays may be of use in further studies of the roles of GSH S-transferase theta enzymes in bioactivation and detoxication and any changes in risk due to polymorphism. Environ Mol Mutagen, 1995, 26(2), 171 - 7 Genotoxicity of m-phenylenediamine and 2-aminofluorene in Salmonella typhimurium and human lymphocytes with and without plant activation; Plewa MJ et al.; The promutagenic arylamines, m-phenylenediamine (mPDA) and 2-aminofluorene (2-AF), were evaluated for their genotoxicity in Salmonella typhimurium strain YG1024 and in human lymphocytes . These agents were assayed with and without TX1MX plant activation mix . Both arylamines without activation were refractory in S . typhimurium, demonstrating that plant activation was required for the generation of their ultimate mutagenic metabolites . However, using the alkaline single-cell gel/Comet assay, both mPDA and 2-AF directly induced DNA damage in human lymphocytes . This effect was reduced when the human cells were treated with the arylamine plus TX1MX . mPDA with or without plant activation was not toxic to the exposed cells . However, at concentrations over 80 microM, 2-AF was toxic to lymphocytes . This toxic response was eliminated by incubation with TX1MX . mPDA and 2-AF were plant-activated into mutagens for S . typhimurium . However, these plant-activated products had a reduced genotoxic potency in human lymphocytes. Environ Mol Mutagen, 1995, 26(2), 155 - 62 Relationships among in vitro mutagenicity assays: quantitative vs . qualitative test results; Benigni R et al.; In previous investigations, we studied the relationships between the profiles of the qualitative responses of in vitro short-term tests (mutation in Salmonella typhimurium, chromosomal aberrations in CHO cells, sister chromatid exchanges in CHO cells, and mutation in mouse lymphoma cells) and common sets of chemicals . In this paper, we address the study of the quantitative responses (potency) . We show that two analyses point to similar patterns of relationships: the mutation in mouse lymphoma cells assay is most similar to the CHO sister chromatid exchange assay, and the Salmonella assay is most similar to the CHO chromosomal aberrations assay. Environ Mol Mutagen, 1995, 25(2), 134 - 47 1-Nitropyrene as a marker for the mutagenicity of diesel exhaust-derived particulate matter in workplace atmospheres; Scheepers PT et al.; The use of 1-nitropyrene (1-NP) as a marker for the occupational exposure to diesel exhaust (DE) mutagens was investigated in workplace atmospheres contaminated with DE from a variety of emission sources, such as power supplies, forklifts, trucks, caterpillar vehicles, trains, ships' engines, and vehicles in city traffic . Total suspended particulate matter was collected by area sampling . The 1-NP content of acetone extracts of these samples as determined by gas chromatography-high resolution mass spectrometry varied from 0.080 to 17 micrograms/g acetone extractable matter, corresponding to air concentrations of 0.012 to 1.2 ng/m3 . A sample collected in a rural area contained 0.0017 ng/m3 1-NP . The mutagenicity of the extracts was tested in the Salmonella typhimurium strains TA98 and TA1538, using the microsuspension assay with and without metabolic activation by an exogeneous metabolizing system (rat liver S9-fraction) . In addition, the S . typhimurium strains YG1021 and YG1024 were used because of their high sensitivity towards the mutagenicity of nitro polycyclic aromatic hydrocarbons . When plotting the mutagenic potency of the air sample extracts as determined in the absence of liver S9 versus the particle-associated 1-NP level, a relatively high correlation (r = 0.80-0.91) was observed in all of the S . typhimurium strains . High correlations (r = 0.80-0.93) were also observed when plotting the results of mutagenicity testing after activation by S9 versus the outcome of chemical analysis . These results show that the 1-NP content of workplace air samples is associated with their mutagenic potency, suggesting that 1-NP may be used as a marker for occupational exposure to DE-derived particle-associated mutagens. Mutat Res, 1995 Jan, 346(1), 57 - 60 Detection of mutagenicity of diphenyl ether herbicides in Salmonella typhimurium YG1026 and YG1021; Oguri A et al.; Three kinds of diphenyl ether herbicides, 4-nitrophenyl 2,4,6-trichlorophenyl ether (CNP, chlornitrofen), 2,4-dichlorophenyl 3-methoxy-4-nitrophenyl ether (chlomethoxynil) and 2,4-dichlorophenyl 3-methoxycarbonyl-4-nitrophenyl ether (bifenox), were tested for mutagenicity in Salmonella typhimurium YG1026 and YG1021, which have high nitroreductase activity, and also in S . typhimurium TA100 and TA98 . CNP and chlomethoxynil showed mutagenicity in S . typhimurium YG1026, without S9 mix, inducing 50 and 304 revertants per microgram . These mutagenicities were suppressed by the addition of S9 mix . CNP and chlomethoxynil were also mutagenic to YG1021 with and without S9 mix, and their mutagenicities were lower than those to YG1026 . On the other hand, bifenox was mutagenic to YG1026 only with S9 mix, inducing 3.0 revertants per micrograms . These three herbicides showed no mutagenicity in S . typhimurium TA100 and TA98 either with or without S9 mix. Mutat Res, 1995 Jan, 341(3), 225 - 34 Geographical variations in mutagenicity of blue rayon extracts of Japanese human bile; Mano H et al.; The mutagenicity of human bile was investigated in the Ames test after blue rayon treatment . In the present study, 52 and 59 bile samples were collected from the high and the low risk population for gallbladder cancer (GBC), respectively . The bile mutagenicity was detected only when the blue rayon extracts of bile were assayed with Salmonella typhimurium TA98 in the presence of S9 mix . Thirty-two (61.5%) of 52 samples obtained from the high risk population were mutagenic . In our previous study (Mano et al., 1993), the mutagenicity was observed in 14 (58.3%) of 24 samples . After combining this data with the results of the present study, 46 (60.5%) of 76 samples revealed the mutagenicity . On the other hand, the mutagenicity was detected in only 7 (11.9%) of 59 samples collected from the low risk population . Therefore, we found a significant geographical difference in the bile mutagenicity. Adv Exp Med Biol, 1995, 371B, 1653 - 7 Assessment of attenuated Salmonella typhimurium strains designed as potential carriers of foreign antigens for mucosal localization and immuno-genicity in a rabbit model; Boedeker EC et al.; Neither wild type nor attenuated S . typhimurium strains induced diarrheal illness in rabbits . All strains localized to the Peyer's patch at higher concentrations than in lumenal contents or adjacent ileum . Wild type S . typhimurium C5 induced a typhoid-like illness in rabbits with severe weight loss, bacteremia, persistent splenic colonization, and serum IgG response . Both attenuated strains were disseminated to spleen (day 3) but produced minimal systemic illness . They induced biliary IgA responses greater than the wild type (day 7), but minimal serum IgG responses . Both mutants of S . typhimurium are suitable for further development as live enteric vaccines to carry foreign antigens since they localize to Peyer's patch after oral inoculation, induce biliary antibody, and produce minimal systemic disease . The attenuated strains tested are systemically disseminated . It remains to be determined whether dissemination (determined by a large virulence plasmid) is necessary for the desired mucosal immune response or acceptable for an oral vaccine strain. Chirality, 1995, 7(5), 359 - 64 Comparative toxicity of (+)-(R)- and (-)-(S)-1,2-dibromo-3-chloropropane; Kouzi SA et al.; The haloalkane 1,2-dibromo-3-chloropropane (DBCP), an environmental pollutant that was widely used as a soil fumigant, is a carcinogen and a mutagen and displays target-organ toxicity to the testes and the kidneys . Because little is known about effects of stereochemistry on the metabolism and toxicity of halogenated alkyl compounds and because DBCP, which has a chiral center at C-2, may show enantioselectivity in its metabolism and/or toxicities, the optically pure enantiomers of DBCP were tested in vivo in rats for organ toxicity as well as for bacterial mutagenicity . Organ toxicity studies showed that (S)-DBCP was slightly more renal toxic than (R)-DBCP but was not significantly more toxic than the racemate, and that no significant differences were observed in the extents of testicular necrosis and atrophy caused by either enantiomer or the racemate . In contrast, (R)-DBCP was more mutagenic than either (S)-DBCP or the racemate to Salmonella typhimurium (S . typhimurium) strains TA 100 and TA104 . However, there was little or no enantioselectivity in glutathione S-transferase (GST)-catalyzed conjugation reactions of glutathione with DBCP based on the lack of selectivity in the rates of disappearance of the enantiomers of DBCP in the presence of glutathione (GSH) and GSTs as monitored by chiral gas chromatography (GC). Microbios, 1995, 81(327), 93 - 101 Local skin reaction in mice and guinea pigs induced by a single intradermal inoculation of Fusobacterium necrophorum lipopolysaccharide; Kanoe M et al.; Dermal responses induced by Fusobacterium necrophorum strain VPI 2891 lipopolysaccharide (LPS) were studied using mice and guinea pigs . In ddY mice, the LPS elicited inflammatory, haemorrhagic lesions and an increase in local vascular permeability 24 h postinjection . Of the mouse strains, C3H/HeJ mice were less sensitive . The LPS induced erythema and haemorrhagic responses in guinea pig skin 24 h postinoculation . These responses were dose-dependent . The intensity of dermal inflammation-inducing activity of F . necrophorum LPS was similar to that of Escherichia coli strain 055:B5 LPS, but weaker than that of Salmonella typhimurium LPS . These findings suggest that the fusobacterial LPS may play an important role in contributing to produce the initial lesions in the bacterial infection. Biochemistry, 1994 Dec 20, 33(50), 14957 - 64 Supramolecular self-assembly of glutamine synthetase: mutagenesis of a novel intermolecular metal binding site required for dodecamer stacking; Dabrowski MJ et al.; Dodecameric glutamine synthetase (GS) from Escherichia coli assembles into highly ordered supramolecular protein tubes in the presence of several divalent metal ions . The molecular mechanism for this metal-induced self-assembly of the E . coli GS has been studied by molecular modeling and site-directed mutagenesis . The X-ray crystal structure of the nearly identical Salmonella typhimurium GS has been used to construct a model of the "stacked" complex between two dodecamers . A complementary fit, based on steric constraints, reveals a possible interaction between the N-terminal helices from adjacent dodecamers . The amino acid side chains of His and Met residues within the helices from each of the subunits of one face of a dodecamer lie within approximately 3.5 A of the analogous side chains in the subunits from the adjacent dodecamer in the stacked complex . His-4, Met-8, and His-12 from adjacent helices provide potential ligands for a binuclear metal binding site . Replacement of each of these surface residues with aliphatic amino acids has negligible effects on the enzymatic activity, the regulation of activity via adenylylation, and gross dodecameric structure . However, the rate and extent of metal ion-mediated self-assembly of GS tubules are reduced to < 2% of the wild-type protein in the single mutants H4A, H12L, and H12D . The M8L mutant demonstrates a 3-fold decrease in the bimolecular rate constant for stacking, but electron microscopy indicates that this mutant does form stacked tubes . The cysteine-containing mutants H4C, M8C, and H12C were also constructed.(ABSTRACT TRUNCATED AT 250 WORDS) J Immunol, 1994 Dec 15, 153(12), 5634 - 42 Construction, expression, and immunogenicity of multiple tandem copies of the Schistosoma mansoni peptide 115-131 of the P28 glutathione S-transferase expressed as C-terminal fusions to tetanus toxin fragment C in a live aro-attenuated vaccine strain of Salmonella; Khan CM et al.; Genetic fusions have been constructed between the highly immunogenic but atoxic fragment C of tetanus toxin and a guest peptide, aa115-131, from the protective 28-kDa glutathione S-transferase Ag of Schistosoma mansoni . Fusions have been assembled to express one, two, four, and eight tandem copies of the peptide . The recombinant vectors have been electroporated into the nonvirulent aroA strain of Salmonella typhimurium SL3261 . The fusion proteins are soluble and stably expressed in Salmonella as evaluated by Western blotting with fragment C and glutathione S-transferase antisera . Mice have been immunized i.v . with a single dose of the live recombinant salmonellae . The strains are stable in mice and elicit Ab responses directed against fragment C, as determined by enzyme-linked immunosorbent assays . Ab responses were also detected against the guest peptide . The Ab responses improved dramatically toward the aa115-131 peptide with increasing copy number, with the octameric "repitope" fusion displaying the greatest potency . This approach may represent a general strategy for eliciting immune responses against peptides in live bacterial vaccines. J Bacteriol, 1994 Dec, 176(24), 7630 - 7 Molecular characterization of the Salmonella typhimurium flhB operon and its protein products; Minamino T et al.; The flhB and flhA genes constitute an operon called flhB operon on the Salmonella typhimurium chromosome . Their gene products are required for formation of the rod structure of flagellar apparatus . Furthermore, several lines of evidence suggest that they, together with FliI and FliH, may constitute the export apparatus of flagellin, the component protein of flagellar filament . In this study, we determined the nucleotide sequence of the entire flhB operon from S . typhimurium . It was shown that the flhB and flhA genes encode highly hydrophobic polypeptides with calculated molecular masses of 42,322 and 74,848 Da, respectively . Both proteins have several potential membrane-spanning segments, suggesting that they may be integral membrane proteins . The flhB operon was found to contain an additional open reading frame capable of encoding a polypeptide with a calculated molecular mass of 14,073 Da . We designated this open reading frame flhE . The N-terminal 16 amino acids of FlhE displays a feature of a typical signal sequence . A maxicell labeling experiment enabled us to identify the precursor and mature forms of the flhE gene products . Insertion of a kanamycin-resistant gene cartridge into the chromosomal flhE gene did not affect the motility of the cells, indicating that the flhE gene is not essential for flagellar formation and function . We have overproduced and purified N-terminally truncated FlhB and FlhA proteins and raised antibodies against them . By use of these antibodies, localization of the FlhB and FlhA proteins was analyzed by Western blotting (immunoblotting) with the fractionated cell extracts . The results obtained indicated that both proteins are localized in the cytoplasmic membrane. J Bacteriol, 1994 Dec, 176(24), 7625 - 9 Isolation and characterization of FliK-independent flagellation mutants from Salmonella typhimurium; Kutsukake K et al.; A flagellum of Salmonella typhimurium and Escherichia coli consists of three structural parts, a basal body, a hook, and a filament . Because the fliK mutants produce elongated hooks, called polyhooks, lacking filament portions, the fliK gene product has been believed to be involved in both the determination of hook length and the initiation of the filament assembly . In the present study, we isolated two mutants from S . typhimurium which can form flagella even in the absence of the fliK gene product . Flagellar structures were fractionated from these suppressor mutants and inspected by electron microscopy . The suppressor mutants produced polyhook-filament complexes in the fliK mutant background, while they formed flagellar structures apparently indistinguishable from those of the wild-type strain in the fliK+ background . Genetic and sequence analyses of the suppressor mutations revealed that they are located near the 3'-end of the flhB gene, which has been believed to be involved in the early process of the basal body assembly . On the basis of these results, we discuss the mechanism of suppression of the fliK defects by the flhB mutations and propose a hypothesis on the export switching machinery of the flagellar proteins. Carcinogenesis, 1994 Dec, 15(12), 2899 - 903 Mutagenicity of nitric oxide is not caused by deamination of cytosine or 5-methylcytosine in double-stranded DNA; Schmutte C et al.; Several human tumors of diverse histological origin have a high incidence of C:G to T:A transition mutations at methylated CpG sites in tumor suppressor genes . We used a sensitive genetic assay to examine the ability of nitric oxide (NO), a physiological intra- and intercellular messenger molecule, to promote these transitions by deaminating cytosine (C) or methylcytosine (5mC) in double-stranded DNA . Exposure of a test double-stranded plasmid containing C or 5mC at the target site to NO in phosphate-buffered solution at pH 7.4 followed by transformation into Escherichia coli ung- strain to avoid repair of U did not result in a significant increase in reversion frequency . In addition, exposure of E . coli transformed with the target plasmid to an NO-releasing spermine-NO complex during log-phase growth did not result in larger numbers of revertants, whereas Salmonella typhimurium strain TA1535 showed a dose-responsive increase in reversion frequency when treated in the same way . We conclude that genotoxicity of NO is not caused by deamination of C or 5mC to U or T, respectively, in double-stranded DNA . This is supported by the finding that extracts of TA1535 contained high uracil-DNA glycosylase activity, suggesting that the difference in mutagenesis between the strains is not due to a lack of uracil repair . Therefore, mutational hot-spots seen in human tumor tissues at CpG sites are probably not due to the action of NO at 5mC. Epidemiol Infect, 1994 Dec, 113(3), 425 - 34 Changing epidemiology of human salmonellosis in Hong Kong, 1982-93; Wong SS et al.; A comprehensive analysis of the epidemiology of salmonellosis in a major hospital in Hong Kong from 1982-93 is reported . The trend of salmonella isolations over the past 12 years and changes in the occurrence of individual serotypes are delineated . A total of 5328 isolates were analyzed . Groups B (Salmonella typhimurium and S . derby) and E (S . anatum) were the commonest serogroups isolated from the intestinal tract in all age groups . A significant increase in the isolation of group D salmonellae has been observed since 1989 . This is accounted for by a substantial rise in S . enteritidis isolation as seen in Western countries, despite a concomitant decrease of S . typhi . The extraintestinal isolation index (EII) is proposed as an index of the virulence potential of individual serotypes and serogroups . Group D salmonella was found to be the most invasive serogroup . While group D was the predominant serogroup isolated from extraintestinal sites in patients older than 1 year, group B serotypes (especially S . typhimurium) were more frequently seen in infants younger than 12 months. J Immunol, 1994 Dec 1, 153(11), 4925 - 33 Phagocytic processing of exogenous particulate antigens by macrophages for presentation by class I MHC molecules; Harding CV et al.; Exogenous Ags that are processed in vacuolar endocytic compartments are generally presented by class II MHC molecules and not class I MHC (MHC-I) molecules, which conventionally present cytoplasmic or endogenous Ags . Accordingly, i.v . immunization of C57BL/6 mice with soluble OVA did not elicit a CD8 T cell response . However, i.v . immunization with OVA coupled to Latex particles (Latex-OVA) elicited an OVA-specific CD8 T cell response in vivo (particles from 59 to 2000 nm diameter were effective) . In vitro, Latex-OVA was processed by H-2b macrophages and presented by Kb at least 100- to 1000-fold more efficiently than was soluble OVA . Inhibition of phagocytosis by cytochalasin D blocked the processing of Latex-OVA, whereas processing was not blocked by Brefeldin A . Latex-OVA was presented directly by H-2b macrophages or after "regurgitation" of processed OVA peptide from viable MHC-disparate macrophages for binding to surface Kb molecules on fixed H-2b macrophages . Peptide regurgitation was observed during processing of both Latex-OVA and Salmonella typhimurium 14028s that express an OVA fusion protein (Crl-OVA) . However, the regurgitation pathway was less efficient than direct processing by viable H-2b macrophages . Thus, macrophages express an alternate pathway that allows MHC-I presentation of vacuolar exogenous particulate Ags, including inert synthetic particles without lipid membranes and intravacuolar bacteria . Peptides from these Ags are released from intracellular compartments to bind to surface MHC-I molecules, but peptide-MHC-I complexes also may be generated within intracellular compartments. Infect Immun, 1994 Dec, 62(12), 5519 - 27 Development and evaluation of an experimental vaccination program using a live avirulent Salmonella typhimurium strain to protect immunized chickens against challenge with homologous and heterologous Salmonella serotypes; Hassan JO et al.; A stable live avirulent, genetically modified delta cya delta crp Salmonella typhimurium vaccine strain, chi 3985, was used in several vaccination strategies to evaluate its use in the control of Salmonella infection in chickens . Oral vaccination of chickens at 1 and at 14 days of age with 10(8) CFU of chi 3985 protected against invasion of spleen, ovary, and bursa of Fabricius and colonization of the ileum and cecum in chickens challenged with 10(6) CFU of virulent homologous Salmonella strains from group B . Chickens challenged with heterologous Salmonella strains from groups C, D, and E were protected against visceral invasion of spleen and ovary, while invasion of the bursa of Fabricius and colonization of ileum and cecum was reduced in vaccinated chickens . Oral vaccination at 2 and at 4 weeks of age induced an excellent protection against challenge with virulent group B Salmonella serotypes and very good protection against challenge with group D or E Salmonella serotypes, while protection against challenge with group C Salmonella serotypes was marginal but significant . Vaccination at 2 and at 4 weeks of age also protected vaccinated chickens against challenge with 10(8) CFU of highly invasive S . typhimurium or S . enteritidis strains . The protection of chickens vaccinated with chi 3985 against challenge with homologous and heterologous Salmonella serotypes is outstanding, and the complete protection against ovarian invasion in chickens challenged with 10(8) CFU of highly invasive S . typhimurium or S . enteritidis strains suggests that vaccination of chickens with chi 3985 can complement the present hygiene- and sanitation-based Salmonella control measures . This paper reports a breakthrough in the use of live avirulent vaccine to control Salmonella carriers in chickens. Immunology, 1994 Dec, 83(4), 670 - 4 Antigen expressed by Salmonella typhimurium is processed for class I major histocompatibility complex presentation by macrophages but not infected epithelial cells; Harding CV et al.; Macrophages were shown to mediate class I major histocompatibility complex (MHC-1) presentation of a fusion protein (Crl-OVA) expressed in Salmonella typhimurium, a bacterium which fails to escape from vacuolar compartments after phagocytosis or penetration into host cells . Salmonella typhimurium also penetrates into non-phagocytic intestinal epithelial cells, a portal of entry for systemic infection . We tested the ability of infected epithelial cells to process antigen expressed by S . typhimurium for presentation by MHC-I molecules to CD8+ T cells . CMT-93 murine adenocarcinoma cells expressed Kb and effectively presented the OVA 257-264 peptide to CD8 OVA T-hybridoma cells, but infected CMT-93 cells failed to process Crl-OVA expressed in S . typhimurium . Therapeutically useful MHC-I-restricted cytotoxic T-lymphocyte (CTL) responses may be generated by macrophage presentation of Salmonella antigens or recombinant antigens expressed in Salmonella vaccine vectors . Our data suggest that an inability of epithelial cells to present these antigens may limit the utility of CTL in epithelial immunity in salmonellosis, but studies of additional epithelial cell systems are needed. Epidemiol Mikrobiol Imunol, 1994 Dec, 43(4), 177 - 9 {Distribution of Salmonella typhimurium phage types isolated from various sources in the Slovak Republic 1992-1993}; Majtanova L; The author assessed phagotypes of Salmonella typhimurium strains isolated in 1992 and 1993 from patients with salmonellosis (n = 1,099) from foods (mainly home pig-slaughtering) (n = 10), surface water (n = 1) and one case of a nosocomial infection . In the reference laboratory for phagotyping of Salmonellae a total of 1,111 strains were examined -376 in 1992 and 735 in 1993 . During this period phagotypes 2b dominated (27.81%), 1 (26.28%) and 1 variant (25.02%), whereby in 1993 among the examined strains phagotypes 1 and 1 variant predominated (37% and 36.8% resp.) . All strains isolated from foodstuffs in 1993 belonged to these two phagotypes . Types of 12.8% of the total number of examined strains could not be identified. Arzneimittelforschung, 1994 Dec, 44(12), 1366 - 8 Mutagenicity studies of benzalazine; Herzog R et al.; Benzalazine (2-hydroxy-5-{(4-carboxyphenyl) azo} benzoic acid, CAS 64896-26-0), a new agent for the treatment of ulcerative colitis and Crohn's disease of the large intestine, was studied for genotoxic effects by using the following short-term in vitro and in vivo test: 1 . reverse mutation test (Ames method) on Salmonella typhimurium, 2 . HGPRT (hypoxanthine-guanine phosphoribosyl transferase) point mutation test on V79 hamster cells, 3 . in vivo cytogenetic test on Chinese hamster cells, and 4 . in vivo sister chromatid exchange test on Chinese hamster cells . Benzalazine did not show any positive response in the reverse mutation test, HGPRT-point mutation test, in vivo cytogenetic and sister chromatid exchange test. Indian J Med Res, 1994 Dec, 100, 266 - 7 An outbreak of multidrug resistant Salmonella typhimurium in Delhi (India); Wattal C et al.; A total of 85 patients with multidrug resistant S . typhimurium were isolated between May and September 1991 at the Sir Ganga Ram Hospital, New Delhi, India . Fifty eight (72.5%) patients out of 80 stool culture positives suffered from enteritis and 23 (39.6%) of them settled with oral rehydration therapy alone . All strains were sensitive to 4 aminoquinolones (oflaxcin) but five were resistant to third generation cephalosporin (Cefotaxime; MIC between 50-75 micrograms/ml) whereas 88-96 per cent isolated were resistant to most of the other antibiotics . The convalescent carrier rate was prolonged with the use of antibiotics . The phage type of S . typhimurium isolated from the index and other cases was 178 and multidrug resistance strains had seven plasmids (1.2 to 16 kb) . Barrier nursing and sodium hypochlorite disinfection helped in limiting the outbreak. Comput Chem, 1994 Dec, 18(4), 391 - 6 Artificial neural networks applied to classification of mutagenic activity of nitro-substituted polycyclic aromatic hydrocarbons; Song XH et al.; Three-layer artificial neural networks (ANN) with back-propagation of error have been applied to classification of nitro-substituted polycyclic aromatic hydrocarbons (NPAH) based on the regularity that the structure difference of NPAH compounds leads to different mutagenic activity towards Salmonella typhimurium . The network's architecture and parameters were optimized to give maximum correct classification rate of 93.8% for two different classes of NPAHs: weakly active and strongly active ones . The results compared favourably with those obtained by nonlinear mapping pattern recognition method . Considering that the most important factor for NPAH's mutagenicity might be the electron effect of the substituted nitro-groups, an electrotopological state index of nitrogen atom was introduced additionally as one of network's inputs, and the correct classification rate was consequently raised to 97.5% . The network's prediction ability for untrained samples was also satisfactory. Appl Environ Microbiol, 1994 Dec, 60(12), 4345 - 50 Flow cytometric analysis of the cellular DNA content of Salmonella typhimurium and Alteromonas haloplanktis during starvation and recovery in seawater; Lebaron P et al.; Flow cytometry was used to investigate the heterogeneity of the DNA content of Salmonella typhimurium and Alteromonas haloplanktis cells that were starved and allowed to recover in seawater . Hoechst 33342 (bisbenzimide) was used as a DNA-specific dye to discriminate between DNA subpopulations . The DNA contents of both strains were heterogeneous during starvation . S . typhimurium cells contained one or two genomes, and A . haloplanktis cells contained up to six genomes . S . typhimurium genomes were fully replicated at the onset of starvation . Each replication cycle was completed in the early stage of starvation for A . haloplanktis by stopping cells in the partition step of the cell cycle prior to division . Multigenomic marine cells can undergo rapid cell division without DNA synthesis upon recovery, resulting in large fluctuations in the DNA contents of individual cells . In contrast, the heterogeneity of the DNA distribution of S . typhimurium cells was preserved during recovery . The fluctuations in the DNA fluorescence of this strain seem to be due to topological changes in DNA . Flow cytometry may provide a new approach to understanding dynamic and physiological changes in bacteria by detecting cellular heterogeneity in response to different growth conditions. Appl Environ Microbiol, 1994 Dec, 60(12), 4263 - 7 Reduction and mutagenic activation of nitroaromatic compounds by a Mycobacterium sp; Rafii F et al.; Mycobacterium sp . strain Pyr-1 cells, which were grown to the stationary phase in media with and without pyrene, were centrifuged and resuspended in a medium containing 1-nitropyrene . Cells that had been grown with pyrene oxidized up to 20% of the added 1-nitropyrene to 1-nitropyrene-cis-9,10- and 4,5-dihydrodiols . However, cells that had been grown without pyrene reduced up to 70% of the 1-nitropyrene to 1-aminopyrene but did not produce dihydrodiols . The nitroreductase activity was oxygen insensitive, intracellular, and inducible by nitro compounds . Nitroreductase activity was inhibited by p-chlorobenzoic acid, o-iodosobenzoic acid, menadione, dicumarol, and antimycin A . Extracts from cells that had been grown without pyrene activated 1-nitropyrene, 1-amino-7-nitrofluorene, 2,7-dinitro-9-fluorenone, 1,3-dinitropyrene, 1,6-dinitropyrene, and 6-nitrochrysene to DNA-damaging products, as shown in Salmonella typhimurium tester strains by the reversion assay and by induction of the umuC gene . Activation of nitro compounds, as shown by the umu test, was enhanced by NADPH . This study shows that Mycobacterium sp . strain Pyr-1 metabolizes nitroaromatic compounds by both oxidative and reductive pathways . During reduction, it generates products that are mutagenic. Appl Environ Microbiol, 1994 Dec, 60(12), 4255 - 62 Detection of Salmonella typhimurium in dairy products with flow cytometry and monoclonal antibodies; McClelland RG et al.; Flow cytometry, combined with fluorescently labelled monoclonal antibodies, offers advantages of speed and sensitivity for the detection of specific pathogenic bacteria in foods . We investigated the detection of Salmonella typhimurium in eggs and milk . Using a sample clearing procedure, we determined that the detection limit was on the order of 10(3) cells per ml after a total analysis time of 40 min . After 6 h of nonselective enrichment, the detection limits were 10 cells per ml for milk and 1 cell per ml for eggs, even in the presence of a 10,000-fold excess of Escherichia coli cells. Behring Inst Mitt, 1994 Dec, (95), 57 - 66 Synthesis and secretion of bacterial antigens by attenuated Salmonella via the Escherichia coli hemolysin secretion system; Gentschev I et al.; We describe a plasmid system which allows the secretion of foreign antigens in attenuated Salmonella aroA strains by the secretion apparatus of E . coli hemolysin . The gene (or gene fragment) encoding the antigen is inserted in frame into a residual position of the hlyA gene, encoding the HlyA secretion signal (HlyAs) . Generally, the fused gene is efficiently expressed and the synthesized antigen is in part secreted into the culture supernatant and in part exposed on the surface of the producing Salmonella strain . The successful use of this approach is demonstrated with two antigens of Salmonella typhimurium, PagC and SlyA, both of which are potent virulence factors but produced only in small amounts under in vitro culture conditions and two virulence proteins of Listeria monocytogenes, p60 and listeriolysin . Interestingly the listeriolysin fusion protein proved to be cytolytically active and allowed, when expressed in Salmonella, the escape of these bacteria into the cytoplasm of infected macrophages. Microb Pathog, 1994 Dec, 17(6), 409 - 23 Comparison of Salmonella typhi and Salmonella typhimurium invasion, intracellular growth and localization in cultured human epithelial cells; Mills SD et al.; Invasion of the cultured epithelial cell lines HeLa, Henle-407, and Caco-2 (polarized and nonpolarized) by Salmonella typhi and Salmonella typhimurium were compared using conventional gentamicin invasion assays . Additionally, the mechanisms of invasion and intracellular trafficking by S . typhi and S . typhimurium were compared in HeLa cells using indirect immunofluorescence microscopy . S . typhi strain Ty2 was invasive in all human cell lines tested, including apical uptake into polarized Caco-2 cell monolayers . This strain also replicated at levels similar to S . typhimurium strain SL1344 inside HeLa and Henle-407 cells . Indirect immunofluorescence microscopy confirmed that S . typhi, like S . typhimurium, induced membrane ruffles and cytoskeletal rearrangements upon contact with HeLa cell surfaces . Ruffling induced by S . typhi and S . typhimurium was accompanied by macropinocytosis of the fluid phase endocytic marker fluorescein-dextran-sulphate and by aggregation of cell surface class I MHC heavy chain . Intracellular lysosomal trafficking of S . typhi and S . typhimurium in HeLa cells was also studied . The lysosomal membrane glycoprotein marker h-lamp-2 colocalized with S . typhi-containing vacuoles, as previously shown for S . typhimurium . The soluble lysosomal enzyme marker cathepsin D also was found within S . typhi-containing vacuoles to the same extent as previously published for S . typhimurium . The results from this study suggest that S . typhi and S . typhimurium use similar mechanisms for invasion and intracellular trafficking in cultured human epithelial cells. Hum Exp Toxicol, 1994 Dec, 13(12), 861 - 5 Metabolism and genotoxicity of the halogenated alkyl compound tris(2,3-dibromopropyl)phosphate; van Beerendonk GJ et al.; 1 . The genotoxicity of the flame retardant tris(2,3-dibromopropyl)phosphate (Tris-BP) was studied in vivo . Results showed that Tris-BP was highly clastogenic, but it could only initiate a low number of preneoplastic foci in the rat liver in vivo . In Drosophila, Tris-BP could be classified as a cross-linking agent, because it was more clastogenic than mutagenic . The use of completely deuterated Tris-BP as a metabolic probe revealed that cytochrome P450 and most likely the formation of 2-bromoacrolein (2BA) from Tris-BP is important for the observed genotoxic effects . 2 . In contrast to the high mutagenicity of Tris-BP and 2BA in Salmonella typhimurium, we were unable to detect an increase in mutation frequency of 2BA on the hprt locus of human TK6 cell line . In another system, using a shuttle vector modified with 2BA:DNA-adducts, also no increase in mutation frequency could be detected in human cells . This low mutagenicity of 2BA corresponds with its low mutagenicity in Drosophila and its low induction of preneoplastic foci in the rat liver . 3 . Several DNA adducts of 2BA have been identified, including an unstable 3-(bromooxypropyl)thymidine adduct which has the potential to form cross-links and a cyclic 3,N4-(bromo)propeno-deoxycytidine adduct which can possibly be involved in the clastogenicity of Tris-BP . 4 . Taken together, these data indicate that Tris-BP and 2BA may not effectively induce gene mutations in eukaryotic systems, but rather be potent clastogens . Risk assessment of these and related compounds should therefore be based on the knowledge of clastogens rather than mutagens. Tierarztl Prax, 1994 Dec, 22(6), 529 - 31 {The effectiveness in calves of subcutaneous vaccination with the Salmonella vaccine Murivac}; Steinbach G et al.; Subcutaneous administration of a Salmonella typhimurium bacterin, given twice in an interval of two weeks, protected calves against the oral infection with a Salmonella wild strain. Int J Food Microbiol, 1994 Dec, 24(1-2), 137 - 45 Growth and survival of Yersinia enterocolitica, Salmonella and Bacillus cereus in Brie stored at 4, 8 and 20 degrees C; Little CL et al.; The potential of stabilised Brie to support growth of the food-borne pathogens, Yersinia enterocolitica serotypes 0:3 and 0:9, Salmonella typhimurium, S . dublin (both dairy isolates), S . thompson, and Bacillus cereus (3 dairy isolates), after contamination on opening the cheese package was evaluated . Growth kinetics of the different pathogens was determined in relation to inoculum size and storage temperature (4 degrees C, 8 degrees C and 20 degrees C) . Only Y . enterocolitica was found to grow on the surfaces (outer and exposed) of Brie at all three storage temperatures . Growth of this pathogen during refrigerated storage must be avoided to ensure safety . The numbers of B . cereus and Salmonella increased at 20 degrees C but declined at a slow rate during storage at 4 degrees C and 8 degrees C . However, survival of these two pathogens for extended periods at abuse temperatures could pose a health hazard . Predictions from a predictive modelling program (MFS model) and a modelling database (Food Micromodel) were compared to observed growth values in Brie . Although accurate in the case of B . cereus at 20 degrees C, predicted generation times were in general found to be considerably shorter than the observed values, i.e., overall they were 'fail safe' . Predicted lag times, however, were generally longer compared to observed values in the case of Y . enterocolitica and at low inocula for Salmonella, and would 'fail dangerous' if used for predictive purposes. Int J Food Microbiol, 1994 Dec, 24(1-2), 125 - 36 Development of antibiotic-resistant strains for the enumeration of foodborne pathogenic bacteria in stored foods; Blackburn CD et al.; Strains of Aeromonas spp., Salmonella enteritidis phage type 4, Salmonella typhimurium, verotoxigenic Escherichia coli O157:H7 (VTEC) and Yersinia enterocolitica resistant to streptomycin, nalidixic acid and a combination of both antibiotics were selected . When compared with the parent strains, most of the antibiotic-resistant strains had slightly slower growth rates at their optimum incubation temperature but the difference was reduced progressively when the temperature was lowered . Some antibiotic-resistant strains had considerably slower growth rates in the presence of the relevant antibiotic and these were not used further . Several agar and impedance media with added streptomycin and nalidixic acid were assessed for the enumeration of the antibiotic-resistant strains in artificially contaminated stored foods . Differential/selective media were required to enumerate low numbers of antibiotic-resistant strains in certain foods . The following agar and impedance media were selected: Aeromonas Agar (Ryan) for Aeromonas spp., Xylose Lysine Agar and Lysine Iron Cysteine Neutral Red Medium for Salmonella, Eosin Methylene Blue Agar and Coliform Medium for VTEC, and Yersinia Selective Agar without selective agents for Yersinia enterocolitica . The agar and impedance media have been used successfully to enumerate antibiotic-resistant strains inoculated into foods and stored at different temperatures. Biomed Environ Sci, 1994 Dec, 7(4), 346 - 56 Mutagenicity and induction of drug-metabolizing enzyme activity by LPG combustion particulates in rats; Yin XJ et al.; Methylene chloride extracts of particulates from liquefied petroleum gas (LPG) combustion appliance were studied by using Ames test, micronucleus test and inducibility of pulmonary and hepatic aryl hydrocarbon hydroxylase (AHH) and glutathione S-transferase (GST) in rats . The extracts showed mutagenicity for Salmonella typhimurium strain TA98 and its derivatives TA98NR and TA98/1,8-DNP6 with or without S9 mix . The revertants in strains TA98NR and TA98/1,8-DNP6 were less than 40% and 50% of that in strain TA98 without S9 mix, respectively . Positive results were obtained in mouse bone marrow micronucleus assay . Intratracheal instillation of the extracts led to increase in pulmonary (but not hepatic) AHH and GST activities in rats . It was seen that AHH was more sensitive than GST to induction by the extracts. Cancer Lett, 1994 Nov 25, 87(1), 25 - 32 Suppressive effects of the extracts of Japanese edible seaweeds on mutagen-induced umu C gene expression in Salmonella typhimurium (TA 1535/pSK 1002) and tumor promotor-dependent ornithine decarboxylase induction in BALB/c 3T3 fibroblast cells; Okai Y et al.; Some of epidemiological data indicated that ubiquitous consumption of seaweeds in Japan may be a possible protective factor against some types of tumor . To analyse this problem, the authors studied the antimutagenic and antitumor promotion activities in methanol-soluble extracts of typical edible seaweeds which showed suppressive effects on 3-amino-1,4-dimethyl-5H-pyrido{4,3-b}indol (Trp-P-1)-induced umu C gene expression in SOS response of Salmonella typhimurium (TA 1535/pSK 1002) and 12-O-tetradecanoylphorbol-13-acetate (TPA)-dependent ornithine decarboxylase induction in BALB/c 3T3 fibroblast cells . Although eight varieties of edible seaweeds including chlorophyta, Phaenophyta and Rhodophyta showed significant antimutagenic and antipromotion activities, they expressed the activities different from each other . Among these seaweeds, Enteromorpha prolifera ('Sujiaonori' in Japanese) and Porphyra tenera ('Asakusanori') showed relatively strong suppressive activities in both antimutagenic and antipromotion assays compared with other seaweeds . These seaweeds contained considerable amounts of beta-carotene as a possible active principle with anticarcinogenic activity . This compound was partially associated with the antimutagenic activity in the seaweed extract, but did not contribute to the antipromotion activity of seaweed extract under our experimental conditions . These results strongly suggest that Japanese edible seaweeds have possible antimutagenic and antipromotion activities probably associated with antitumor activity. Proc Natl Acad Sci U S A, 1994 Nov 22, 91(24), 11606 - 10 Detection and classification of mutagens: a set of base-specific Salmonella tester strains; Gee P et al.; A detection and classification system for mutagens has been developed that identifies the six possible base-pair substitution mutations . A set of six Salmonella typhimurium (TA7001 to TA7006) strains has been constructed, each of which carries a unique missense mutation in the histidine biosynthetic operon . In addition to the his mutation, these strains carry different auxiliary features that enhance the mutability of the target his mutation . These include the R factor pKM101, which has the SOS-inducible mucAB system; a deletion of the uvrB component of excision repair; and rfa mutations to increase the accessibility of bulky chemicals to the bacteria . Another set of strains (TA7041 to TA7046) contain a wild-type rfa gene . Reversion via the base substitution unique to each strain was verified by sequence analyses of > 800 revertants obtained from different types of mutagens . The strains have considerably lower spontaneous reversion frequencies and detect a variety of mutagens at a sensitivity comparable to the Salmonella tester strains TA100, TA102, and TA104 . The low spontaneous frequency of reversion of a mixture of the six tester strains (approximately 10 revertants per plate) enables a single mutation assay with the mixture that is followed by classification of the type of mutation with the individual strains. Proc Natl Acad Sci U S A, 1994 Nov 8, 91(23), 11261 - 5 Construction, expression, and immunogenicity of the Schistosoma mansoni P28 glutathione S-transferase as a genetic fusion to tetanus toxin fragment C in a live Aro attenuated vaccine strain of Salmonella; Khan CM et al.; A vector has been constructed to allow genetic fusions of guest antigens via a hinge domain to the C terminus of the highly immunogenic C fragment of tetanus toxin . A fusion has been constructed with the gene encoding the protective 28-kDa glutathione S-transferase (EC 2.5.1.18) from Schistosoma mansoni . The recombinant vector has been electroporated into the nonvirulent Salmonella typhimurium aroA live vaccine strain SL3261 . The corresponding chimeric protein is stably expressed in a soluble form in Salmonella as evaluated by Western blotting with fragment C and glutathione S-transferase antisera . Mice immunized intravenously with a single dose of the live recombinant bacteria elicit antibodies to both fragment C and glutathione S-transferase as detected by enzyme-linked immunosorbent assays . Furthermore, all of the mice were solidly protected when challenged with lethal doses of either tetanus toxin or the virulent Salmonella typhimurium strain C5 . Mice have also elicited antibodies to fragment C and glutathione S-transferase after oral immunization . It may be that a live trivalent vaccine against typhoid, tetanus, and schistosomiasis is feasible. J Bacteriol, 1994 Nov, 176(22), 6852 - 60 The Salmonella typhimurium katF (rpoS) gene: cloning, nucleotide sequence, and regulation of spvR and spvABCD virulence plasmid genes; Kowarz L et al.; The spv region of Salmonella virulence plasmids is essential for the development of a systemic infection in mice . Transcriptional activation of the spvABCD operon occurs during stationary growth phase and is mediated by the regulatory gene product SpvR . We have previously shown that expression of a spvRAB'-cat fusion in Escherichia coli was dependent on the katF (rpoS) locus which encodes an alternative sigma factor (sigma S) . The katF gene from Salmonella typhimurium has been cloned, sequenced, and used to construct Salmonella katF mutants by allelic replacement . Using these mutants, we demonstrated by mRNA and gene fusion analyses that sigma S, in conjunction with SpvR, controls the transcription of the regulatory gene spvR . In a second series of experiments, we sought to clarify the relationship between sigma S and SpvR in the control of spvABCD transcription . It was shown that expression of a transcriptional spvAB'-lacZ fusion could be restored in E . coli and Salmonella katF mutants when spvR was expressed in trans from an exogenous promoter . Moreover, identical spvA mRNA startpoints were detected in katF+ and katF strains . These results indicate that the reduction of spvABCD transcription in katF mutants is mainly due to decreased expression of spvR . Finally, mouse inoculation studies with S . typhimurium katF mutants of both wild-type and virulence plasmid-cured strains suggest that katF contributes to Salmonella virulence via the regulation of chromosomal genes in addition to that of spv genes. J Bacteriol, 1994 Nov, 176(21), 6688 - 96 Analysis of promoters controlled by the putative sigma factor AlgU regulating conversion to mucoidy in Pseudomonas aeruginosa: relationship to sigma E and stress response; Martin DW et al.; Alginate overproducition by mucoid Pseudomonas aeruginosa is a critical pathogenic determinant expressed by this organism during chronic infections in cystic fibrosis . Conversion to mucoidy and a subsequent loss of mucoid character can occur via different mutations in the algU mucA mucB gene cluster . The algU gene encodes a 22.2-kDa putative alternative sigma factor required for expression of the critical alginate biosynthetic gene algD . In this work, algU transcription was studied by S1 nuclease protection analysis . Transcription from the promoter proximal to the algU coding region was found to be dependent on AlgU . The -35 and -10 sequences of this newly mapped promoter showed strong similarity ot the promoters of two other critical alg genes: algD and algR . The proximal promoter of algR was also shown to depend on algU . Interestingly, the putative -35 and -10 regions of all three promoters displayed striking similarity to the consensus sequence of the sigma E-dependent promoters in Escherichia coli and Salmonella typhimurium . This 24-kDa sigma factor, controlling genes participating in resistance to high temperatures and oxidative stress, has been previously biochemically characterized, but the gene for sigma E remained unidentified . To examine whether AlgU is related to sigma E, the effect of algU inactivation on the sensitivity of P . aeruginosa to killing by heat and reactive oxygen intermediates was tested . Two isogenic pairs of algU+ and algU mutant strains were compared . The algU mutants, irrespective of the mucoid status of the parental strains, displayed increased sensitivity to killing by paraquat, known to generate intracellular superoxide radicals, and heat . Further lgobal homology searches revealed the presence of a previously unrecognized E . coli gene with the predicted gene product showing a striking 66% identity to AlgU . The corresponding gene from S . typhimurium was cloned and sequenced, and it is displayed one amino acid substitution relative to its E . coli equivalent . AlgU and its close homologs in E . coli and S . typhimurium may be functionally related. Carcinogenesis, 1994 Nov, 15(11), 2605 - 11 Substance-dependent sex differences in the activation of benzylic alcohols to mutagens by hepatic sulfotransferases of the rat; Glatt H et al.; Six primary and 10 secondary benzylic alcohols derived from polycyclic aromatic hydrocarbons were tested for mutagenicity in Salmonella typhimurium TA98 in the presence of varying amounts of hepatic cytosol from adult male and female rats and 3'-phosphoadenosine-5'-phosphosulfate, the cofactor for sulfotransferases . With the exception of 1-(9-anthryl)ethanol, 4H-cyclopenta{def}-phenanthren-4-ol and 10-hydroxy-7,8,9,10-tetrahydrobenzo{a}pyrene, all the benzylic alcohols were activated to mutagens . For 1-(1-pyrenyl)ethanol (1-HEP), 1-(2-pyrenyl)ethanol (2-HEP), 6-hydroxymethylanthanthrene (6-HMAA), 2-hydroxymethylpyrene (2-HMP), 10H-indeno{1,2,7,7a-bcd}pyren-10-ol (OH-IP), 3-hydroxy-3,4-dihydrocyclopenta{cd}pyrene (3-OH-H2-CPcdP) and 1-(6-benzo{a}pyrenyl)ethanol (6-HEBP), this is the first observation of a mutagenic activity . The primary alcohols 1-hydroxymethylpyrene, 2-HMP, 9-hydroxymethylanthracene, 7-hydroxymethyl-12-methylbenz{a}anthracene and 6-hydroxymethylbenzo{a}pyrene, as well as the secondary alcohols 1-HEP and 3-OH-H2-CPcdP, were more efficiently activated by hepatic cytosol from females than by preparations from males (2.6- to 8-fold) . A further compound, 6-HEBP showed significant, but relatively weak, effects in the presence of cytosol from females, whereas it was inactive in the presence of hepatic cytosol from males . The reverse sex difference was observed in the activation of 4H-cyclo-penta{def}chrysen-4-ol, the activity of cytosol from males amounting to about four times that from females . Four other compounds, 2-HEP, 7-hydroxy-7,8,9,10-tetrahydrobenzo{a}pyrene, 6-HMAA and OH-IP, were activated with similar efficiency by hepatic cytosol from both sexes (< two-fold differences) . The study indicates that different sulfotransferases are involved in the bioactivation of benzylic alcohols, including forms preferentially expressed in females as well as forms preferentially expressed in males, and that these enzymes qualitatively differ in their substrate tolerance for benzylic alcohols. Carcinogenesis, 1994 Nov, 15(11), 2523 - 9 Activation of procarcinogens by human cytochrome P450 enzymes expressed in Escherichia coli . Simplified bacterial systems for genotoxicity assays; Shimada T et al.; Bacterial assays were used to examine the activation of 14 known procarcinogens by cytochrome P450 (P450) enzymes . Human P450s 1A1, 1A2 and 3A4 were expressed in Escherichia coli with slight modification of their N-terminal sequences . Genotoxicity was measured by the induction of the SOS response in Salmonella typhimurium NM2009 (TA1535/pSK1002/pNM12), which contains a umuC regulatory sequence attached to the lacZ reporter gene . Conditions for analysis were examined using E . coli membranes and purified enzymes . Membrane fractions, fortified with NADPH-P450 reductase, were found to be useful preparations for measuring activation of the procarcinogens . Conditions of linearity were established for these assays and the systems were applied to several particular problems related to bioactivation of procarcinogens by P450s . The patterns of activation of the 14 individual chemicals were consistent with the literature developed using human liver microsomes, purified liver P450s and other approaches . The P450s expressed in bacterial membranes could be inhibited by antibodies . 7,8-Benzoflavone inhibited P450s 1A1 and 1A2 and stimulated P450 3A4 in the membranes . The contributions of P450s 1A1 and 1A2 were distinguished with some of the arylamines and 7,8-dihydroxy-7,8-dihydrobenzo{a}pyrene . Recombinant P450 3A4 was found to be more active than P450 1A2 in the activation of aflatoxin B1 at all substrate concentrations examined. Carcinogenesis, 1994 Nov, 15(11), 2507 - 16 Synthesis and mutagenicity of the diastereomeric fjord-region 11,12-dihydrodiol 13,14-epoxides of dibenzo{a,l}pyrene; Luch A et al.; Extensive tumorigenicity studies in rodents revealed that dibenzo{a,l}pyrene (DB{a,l}P) is the most potent carcinogen among all polycyclic aromatic hydrocarbons (PAHs) tested so far . The structure of the genotoxic metabolite(s) responsible for this exceptional carcinogenicity is unknown . The fjord-region syn- and anti-DB{a,l}P-11,12-dihydrodiol 13,14-epoxides (syn- and anti-DB{a,l}PDE) were synthesized to clarify their role as possible ultimate mutagenic and carcinogenic metabolites of DB{a,l}P.9-Formyl-11,12-dimethoxybenzo{g} chrysene was prepared from 9-phenanthrylacetic acid by a photochemical route . After reaction of the aldehyde with trimethylsulfonium iodide to generate an oxiranyl side-chain, treatment with boron trifluoride produced the key intermediate 11,12-dimethoxy-DB{a,l}P in 14% overall yield . From 11,12-dimethoxy-DB{a,l}P the syn- and anti-DB{a,l}PDE were stereoselectively prepared via the trans-11,12-dihydrodiol . The mutagenicity of the syn- and anti-DB{a,l}PDE was examined in four his- strains of Salmonella typhimurium and in Chinese hamster V79 cells . In all five test systems, the new dihydrodiolepoxides were more potent than any of the previously investigated dihydrodiolepoxides . The specific mutagenicity observed with anti-DB{a,l}PDE in strain TA104 exhibited the highest value ever found with any compound in any his- strains of S.typhimurium . The same appears to be true for the activity observed with this compound in V79 cells . In all five systems, syn-DB{a,l}PDE was only moderately less active than its anti-diastereomer (approximately 2-fold) . The exceptional mutagenic activities of these dihydrodiolepoxides may be one of the reasons for the exceptional carcinogenic activity of DB{a,l}P. Infect Immun, 1994 Nov, 62(11), 5095 - 101 Further characterization of the PhoP regulon: identification of new PhoP-activated virulence loci; Belden WJ et al.; Salmonella typhimurium survival within macrophages is an essential virulence property necessary to enteric fever pathogenesis . This survival requires coordinate transcriptional activation of virulence genes within acidified macrophage phagosomes . Virulence gene transcription is regulated by a two-component system comprising the PhoP (transcriptional activator) and PhoQ (sensor-kinase) proteins . Thirteen new PhoP-activated loci (designated pagD to pagP) encoding membrane or secreted proteins have been identified by use of the transposon TnphoA . Three of these loci have a chromosomal location that was linked to the previously identified pagC locus . Strains with TnphoA insertions in pagD, pagJ, pagK, and pagM were significantly attenuated for mouse virulence (50% lethal dose greater than 1,000 times that of wild-type bacteria) . No strains with pag::TnphoA insertions were found to have altered sensitivity to the cationic antimicrobial peptide NP-1 defensin . PhoP and PhoQ are pleotropic regulators of membrane or secreted proteins, suggesting that the ability to effect a global change in the expression of these proteins is required for S . typhimurium survival within acidified macrophage phagosomes. Infect Immun, 1994 Nov, 62(11), 4739 - 46 Invasiveness and persistence of Salmonella enteritidis, Salmonella typhimurium, and a genetically defined S . enteritidis aroA strain in young chickens; Cooper GL et al.; Newly hatched chicks were dosed orally with a Salmonella typhimurium wild-type strain, an S . enteritidis wild-type strain, and a genetically defined S . enteritidis aroA vaccine candidate, strain CVL30 . The S . typhimurium strain, 2391 Nalr, was virulent in newly hatched chicks and caused deaths in 7 of 20 chicks after an oral dose of 10(5) organisms . The S . enteritidis wild-type strain, LA5, caused death in 1 of 25 chicks and gross pathology including pericarditis and perihepatitis in 6 of the 24 survivors after an oral dose of 10(9) organisms . S . enteritidis aroA CVL30, attenuated by ca . 6.5 log10 in BALB/c mice, was nonvirulent when administered orally to chicks and did not cause morbidity . When newly hatched chicks were dosed, the pattern of invasion and colonization of the reticuloendothelial system by strain CVL30 was similar to that of its parent strain, LA5, irrespective of the dose . Oral inoculation of newly hatched chicks with < 10 organisms of S . enteritidis LA5 or CVL30 was followed by multiplication in the cecal contents . Within 3 days of hatching, the pH of the cecal contents was reduced from ca . 7 to 5 . Samples of gut contents were inoculated in vitro . The S . enteritidis strains multiplied in samples taken from the ileum and duodenum irrespective of age but multiplied in the cecal samples from newly hatched chicks only . Invasion from the gut by S . enteritidis LA5 and CVL30 was both age and dose dependent. J Toxicol Sci, 1994 Nov, 19(4), 235 - 8 Evidence of partial involvement of P-450 2D in mutagenic activation of benzo(a)pyrene in liver S-9 fraction from untreated rats; Masuda M et al.; In order to clarify which species of cytochrome P-450 is involved in activation of benzo(a)pyrene (BP) in untreated rat liver, strain and sex differences in the ability of rat liver 9000 g supernatant (S-9) to mutagenically activate BP was investigated using Ames test . The numbers of histidine revertants in Ames test after pre-incubation of TA 98 strain of Salmonella typhimurium and BP with liver S-9 from male rats were markedly higher than those obtained using female rats . In addition, a marked strain difference (Wistar > DA) in the ability of liver S-9 from Wistar and DA rats to activate BP was observed . Antibody against cytochrome P-450 2D inhibited up to 50% of the revertant formation by the activation of BP with liver S-9 from male Wistar rats . These results indicate the partial involvement of cytochrome P-450 2D subfamily as well as cytochrome P-450 species specific to male rats in activation of BP to ultimate mutagen in untreated rat liver. Mutagenesis, 1994 Nov, 9(6), 553 - 7 Activation of benzylic alcohols to mutagens by human hepatic sulphotransferases; Glatt H et al.; Four primary and five secondary benzylic alcohols derived from polycyclic aromatic hydrocarbons were tested for mutagenicity in Salmonella typhimurium TA98 in the presence of 3'-phosphoadenosine-5'-phosphosulphate, the cofactor for sulphotransferases, and varying amounts of hepatic cytosol from three or four different human subjects, a 3-year-old child, an adult female, an adult male and one unknown . All compounds except one, 4H-cyclopenta{def}phenanthren-4-ol, were activated to mutagens . The interindividual variation in the activities was at most 3-fold and the individual activities towards the different substrates were correlated with each other . The same compounds had previously been tested in the presence of hepatic cytosol from rats and all compounds activated in one species were also activated in the other species . However, there were marked quantitative differences, which were further complicated by the observation of a substantial sex difference in the rat . Male and female rat liver cytosol showed higher sulphotransferase activities towards 1-hydroxymethylpyrene, 9-hydroxymethylanthracene, 7-hydroxymethyl-12-methylbenz{a}anthracene and 4H-cyclopenta{def}chrysen-4-ol than human liver cytosol . The largest difference in activity was seen with 7-hydroxymethyl-12-methylbenz{a}anthracene, reaching a factor of approximately 100 between human and female rat . However, with other benzylic alcohols, the activity in human liver cytosol was in the range of that found in the less active sex of rat (3-hydroxy-3,4-dihydrocyclopenta{cd}pyrene, 2-hydroxymethylpyrene) or the more active sex of rat {1-(1-pyrenyl)ethanol}.(ABSTRACT TRUNCATED AT 250 WORDS) Mutagenesis, 1994 Nov, 9(6), 547 - 51 9-Methoxytariacuripyrone, a naturally occurring nitro-aromatic compound with strong mutagenicity in Salmonella typhimurium; Schimmer O et al.; 9-Methoxytariacuripyrone, a nitro-aromatic compound isolated from Aristolochia brevipes showed strong mutagenic activity in strain TA98, TA100 and some YG strains of Salmonella typhimurium with and without S9 mix . Incubation with cytosol resulted in a heavy increase in mutagenicity . When incubated with microsomes the activity was dramatically decreased . The results are discussed in view of the enzymes possibly involved in activation and detoxification of the compound . The role of the basic structure on the mutagenicity mediated through the nitro group was also considered. Mutagenesis, 1994 Nov, 9(6), 523 - 6 Moderate inhibition of mutagenicity and carcinogenicity of benzo{a}pyrene, 1,6-dinitropyrene and 3,9-dinitrofluoranthene by Chinese medicinal herbs; Horikawa K et al.; The activity of six Chinese medicinal herbs against the environmental mutagens and carcinogens benzo{a}pyrene (B{a}P), 1,6-dinitropyrene (1,6-diNP) and 3,9-dinitrofluoranthene (3,9-diNF) was determined . Samples of Prunella spica, Rheum palmatum, Polygonum multiflorum, Agrimonia pilosa, Ephedra sinica and Teitoutou were tested in an in vitro system . Antimutagenic activity against B{a}P was marked in the presence of extracts (boiled for 2 h in a water bath) whereas that against 1,6-diNP and 3,9-diNF varied from 20 to 86% . The differences in inhibition might be due to inactivation of metabolic enzymes . An extract of P . multiflorum was divided into ether, ethyl acetate and water soluble fractions, which were tested for antimutagenic activity against B{a}P . The antimutagenic action of the ethyl acetate soluble fraction was substantial and dose-dependent . Tannins and related compounds were the major components of the extract, of which epigallocatechin, epigallocatechin gallate, epicatechin gallate and tannic acid strongly inhibited the mutagenicity of B{a}P (2.5 micrograms/plate) in Salmonella typhimurium TA98 with S9 mix . To confirm the results of the in vitro test system, F344/DuCrj male rats were given a subcutaneous injection of B{a}P . Thereafter, they received water extracts of the six Chinese medicinal herbs for 50 weeks and were examined for tumors . The P . multiflorum extract significantly reduced the tumor incidence. J Toxicol Sci, 1994 Nov, 19 Suppl 3, 487 - 97 {Mutagenicity studies of lactitol (NS-4)}; Iwakura K et al.; Lactitol (NS-4), a hepatic encephalopathy drug, was examined for mutagenicity in the reverse mutation test in bacteria, the chromosome aberration test with cultured mammalian cells, and the micronucleus test in mice . 1 . In the reverse mutation test using Salmonella typhimurium (TA1535, TA100, TA1537, and TA98) and Escherichia coli (WP2uvrA), the drug did not significantly increase revertant colonies in any of the test strains with or without metabolic activation system (S-9mix) . 2 . In the chromosome aberration test with cultured Chinese hamster lung cells (CHL/IU), the drug did not significantly increase aberrant cells in the direct method or in the metabolic activation method . 3 . In the micronucleus test with Slc:ddY male mice, the drug did not significantly increase micronucleated polychromatic erythrocytes in the bone marrows . These results suggest that lactitol has no mutagenicity in vitro or in vivo. Lett Appl Microbiol, 1994 Nov, 19(5), 294 - 8 Evaluation of different DNA extraction procedures for the detection of Salmonella from chicken products by polymerase chain reaction; Soumet C et al.; Polymerase chain reaction (PCR) was used after a short pre-enrichment culture to detect Salmonella subspecies in chicken fillets . A direct PCR assay performed with chicken meat inoculated with Salmonella Typhimurium produced no PCR products . Six different DNA extraction protocols were tested to recover efficiently Salmonella DNA after a short incubation period . Three of them gave results that were reliable, rapid and sensitive . Successful protocols used Proteinase K and/or a centrifugation step to concentrate the samples . For reliable detection of Salmonella subspecies, a few thousand bacterial cells per ml must be present . To obtain this number of bacterial cells with an inoculation of about one cell in 25 g of ionized food products, it was necessary to incubate samples for at least 10 h before PCR . A larger inoculum of approximately 10 cells in 25 g of ionized food products, required 8 h in culture broth to give positive results by PCR-based assay. Chem Res Toxicol, 1994 Nov-Dec, 7(6), 779 - 83 Interactive chlorine-by-bromine and hydrogen-by-hydroxyl group replacement effects in 2(5H)-furanone mutagenicity; LaLonde RT et al.; Both bromine- and chlorine-substituted 2(5H)-furanones are produced by the chlorination of ligno-humic waters containing bromide ion . The molar mutagenicities of four bromine- and chlorine-substituted 2(5H)-furanones were determined by the Salmonella typhimurium (TA100) assay to explore Cl-by-Br and H-by-OH replacement effects on mutagenicity . Each of these two replacements was expected to enhance mutagenicity based on earlier work showing that lower LUMO energy levels and greater radical anion stability correlated with elevated TA100 mutagenicity . The four compounds investigated were the following: 2,3-dibromo-5-hydroxy-2(5H)-furanone (mucobromic acid, MBA); 2,3-dibromo-2(5H)-furanone (reduced mucobraomic acid, RMBA); 2,3-dichloro-5-hydroxy-2(5H)-furanone (mucochloric acid, MCA); and 2,3-dichloro-2(5H)-furanone (reduced mucochloric acid, RMCA) . Mean molar mutagenicities were found to be 5.54, 1.18, 2.92 and 0.105 revertants/nmol for the four compounds in the order named . Mutagenicity enhancements resulting from Cl-by-Br and H-by-OH replacements were analyzed by simple ratios of mean molar mutagenicity and by multiple regression analysis . The effect of the Cl-by-Br replacement on mutagenicity amounted to a 1.9-fold enhancement in the presence of C-5 OH, but an 11-fold enhancement in the presence of C-5 H . This demonstrated that the two replacement effects were interactive . Higher mutagenicity values corresponded to lower AM1 computed LUMO energy levels and greater radical anion stabilities. Mutat Res, 1994 Nov 1, 311(1), 9 - 20 Mutational spectrum of revertants in the hisD3052 allele of Salmonella typhimurium induced by hydrogen peroxide-activated benzidine; Wallace RE et al.; Benzidine is mutagenic in a modified Ames (Salmonella typhimurium) assay, which uses hydrogen peroxide-dependent peroxidative activation . The mutational specificity of benzidine was investigated in tester strain TA98, which reverts by frameshifts of the hisD3052 allele . The most frequently observed mutation is a deletion of two bases from a (CG)4 run . This deletion was elevated in frequency among benzidine-induced revertants, relative to spontaneous revertants . Many other mutations were also observed, including additions, deletions, and complex events . Only small frameshifts were observed among the benzidine-induced revertants, whereas some larger deletions were observed among the spontaneous revertants. Mutat Res, 1994 Nov 1, 311(1), 149 - 56 Structure-mutagenicity relationships in series of 11H-indolo{3,2-c}quinoline-1,4-diones, tetrahydro-11H-indolo{3,2-c}quinoline-1,4-diones and 11H-pyrido{3',4':4,5}pyrrolo{3,2-c}quinoline-1,4-diones with leukemia cytotoxic properties . Relations with topoisomerase I inhibiting properties; Callais F et al.; Six heterocyclic quinones with topoisomerase I inhibiting properties and cytotoxic activities on L1210 leukemia cells were studied for their mutagenicity in four strains of Salmonella typhimurium . The tested compounds are 3-methoxyindolo{3,2-c}quinoline-1,4-diones and their derivatives in which the common pyrroloquinoline nucleus is annelated either with a benzene or a cyclohexane on a pyridine ring . Almost all quinones were found to be direct-acting mutagens at different levels in all strains, mainly TA97a and TA98 . Relations were established between their structure and their mutagenic activities . The mutagenicity was found to be influenced (i) by the nature of the fourth nucleus: the pyridinic compounds were the most active, the non-aromatic ones were practically inactive; (ii) by the presence of a methyl group in the 6-position that decreased the mutagenicity . Then, the mutagenic properties were compared with the topoisomerase I inhibiting property that is one of the possible mechanisms of action for these cytotoxic quinones . The results indicated a correlation between mutagenicity and enzyme inhibiting properties. Mutat Res, 1994 Nov, 341(1), 71 - 5 Antimutagenicity of lemon grass (Cymbopogon citratus Stapf) to various known mutagens in salmonella mutation assay; Vinitketkumnuen U et al.; Lemon grass (Cymbopogon citratus Stapf) was extracted with 80% ethanol . The extract was not found to be mutagenic in the Salmonella mutation test with or without metabolic activation . However, the extract was found to possess antimutagenic properties towards chemical-induced mutation in Salmonella typhimurium strains TA98 and TA100 . Mutagenicity of AFB1, Trp-P-1, Trp-P-2, Glu-P-1, Glu-P-2, IQ, MNNG and AF-2, was inhibited by the extract of lemon grass in a dose-dependent manner, but no effect was found on the mutagenic activity of benzo{a}pyrene. Mutat Res, 1994 Nov, 341(1), 1 - 15 Study of the genotoxic activity of five chlorinated propanones using the SOS chromotest, the Ames-fluctuation test and the newt micronucleus test; Le Curieux F et al.; Three short-term assays (the SOS chromotest, the Ames-fluctuation test and the newt micronucleus test) were carried out to evaluate the genotoxicity of five chlorinated propanones identified in several chlorinated waters (monochloropropanone, 1,1-dichloropropanone, 1,3-dichloropropanone, 1,1,1-trichloropropanone and 1,1,3-trichloropropanone) . In the SOS chromotest, all the compounds except monochloropropanone were found to induce primary DNA damage in Escherichia coli . With the fluctuation test, all five chloropropanones showed mutagenic activity on Salmonella typhimurium strain TA100 . The newt micronucleus assay detected a clastogenic effect on the peripheral blood erythrocytes of Pleurodeles waltl larvae only for 1,3-dichloropropanone and 1,1,3-trichloropropanone . Moreover, two structure-activity relationships are noticeable: (1) chloropropanones with chlorine substituents on both carbon positions (1,3-DCP and 1,1,3-TCP) are by far more genotoxic than chloropropanones substituted only on one carbon position (1,1-DCP and 1,1,1-TCP); (2) the increase of the number of chlorine substituents decreases the mutagenic activity (fluctuation test) of the chlorinated propanones studied. Mutat Res, 1994 Nov, 325(2-3), 65 - 74 Genotoxicity of dithiocarbamates and their metabolites; Franekic J et al.; Dithiocarbamate fungicides are widely used in agriculture for protection of vegetable crops and seeds . The mutagenicity spectra of ziram, thiram, zineb S-65 and ETU were determined by employing a battery of test systems included the bacterium Salmonella typhimurium (strains TA98, TA100, TA102, TA104, TA1535, TA1538), the yeast Saccharomyces cerevisiae (strain D61.M) and the shallot Allium ascalonicum somatic cells . Plate incorporation assay with S . typhimurium demonstrated direct mutagenicity of ziram in TA100 and thiram in TA100 and TA98 whereas zineb S-65 and ETU were ineffective . Tests for mitotic chromosome malsegregation in S . cerevisiae D61.M gave positive results with thiram, zineb S-69 and ETU . In shallot somatic root-tip cells ziram, thiram and ETU induced different genetic damages e.g . mitotic disturbance, polyploidy and micronuclei. Infect Immun, 1994 Nov, 62(11), 4969 - 74 Salmonella typhimurium invasion of epithelial cells: role of induced host cell tyrosine protein phosphorylation; Rosenshine I et al.; Salmonella typhimurium invades nonphagocytic epithelial and fibroblast cells via a process resembling phagocytosis . We have compared some phenotypes that are involved in S . typhimurium invasion by using different host cell lines, including HeLa, Henle-407, and A431 . Infection with either wild-type S . typhimurium, bacterial culture supernatant, or the noninvasive invA mutant was associated with induction of tyrosine phosphorylation of host cell mitogenic activating protein kinase . However, we did not detect induction of tyrosine phosphorylation of the epidermal growth factor receptor in S . typhimurium-infected cells . Treatment with the tyrosine protein kinase inhibitor genistein did not reduce S . typhimurium invasion into any of these cell lines . These results suggest that S . typhimurium invasion is independent of host cell epidermal growth factor receptor activation. Biochem Biophys Res Commun, 1994 Oct 28, 204(2), 937 - 43 Hepatic metabolism of chloral hydrate to free radical(s) and induction of lipid peroxidation; Ni YC et al.; Metabolism of chloral hydrate by male B6C3F1 mouse liver microsomes generates free radical intermediate(s) as evidenced by electron spin resonance spectroscopic analysis . The subsequent induction of endogenous lipid peroxidation was shown by analysis of the resulting products with high-pressure liquid chromatography . Chloral hydrate was found mutagenic in Salmonella typhimurium strain TA104 . Both lipid peroxidation and mutagenicity were efficiently inhibited by free radical scavengers, alpha-tocopherol and menadione. J Biol Chem, 1994 Oct 28, 269(43), 26591 - 3 Structural and kinetic analysis of a channel-impaired mutant of tryptophan synthase; Schlichting I et al.; Substrate channeling is a process by which two sequential enzymes interact to transfer a metabolite (or intermediate) from one enzyme active site to the next without allowing free diffusion of the metabolite . Channeling is thought to play an important role in metabolic regulation and cellular modulation of enzymatic activities . Although there are numerous examples of sequential enzyme pairs in glycolysis and other biosynthetic pathways that are thought to exhibit channeling, this is as yet controversial . Tryptophan synthase is considered the best example for an enzyme displaying channeling behavior between subunits . Tryptophan synthase is an alpha 2 beta 2 tetrameric enzyme complex, which catalyzes the last two steps in the biosynthesis of L-tryptophan . The alpha subunit catalyzes the cleavage of indole-3-glycerol phosphate to indole and glyceraldehyde-3-phosphate; the beta subunit catalyzes the condensation of indole with serine to form tryptophan, in a reaction mediated by pyridoxal phosphate . The inability to trap free indole in the steady-state reaction and analysis of the kinetics of single turnover reactions have led to the postulate that indole may pass directly from the alpha to the beta site without diffusion through solution (Demoss, J . A . (1962) Biochim . Biophys . Acta 62, 279-293; Matchett, W . M . (1974) J . Biol . Chem . 249, 4041-4049) . The crystal structure of tryptophan synthase from Salmonella typhimurium has provided additional support for substrate channeling by elucidating a 25-A hydrophobic tunnel connecting the two catalytic sites (Hyde, C . C., Ahmed, S . A., Padlan, E . A., Miles, E . W., and Davies, D . R . (1988) J . Biol . Chem . 263, 17857-17871) . The structure suggests that mutation of a residue lining the tunnel to a more bulky residue might impede or block the passage of indole during catalysis thus enabling detection of indole during a single enzyme turnover . A mutant of tryptophan synthase has been prepared in which one of the residues lining the tunnel, beta Cys-170, has been replaced with a bulkier tryptophan residue . Kinetic and structural analyses of the beta C170W mutant by rapid chemical quench methods and x-ray crystallographic analysis show both the transient formation of indole and the obstruction of the tunnel, thus providing direct evidence for the substrate channeling mechanism. J Biol Chem, 1994 Oct 21, 269(42), 26503 - 11 The cobC gene of Salmonella typhimurium codes for a novel phosphatase involved in the assembly of the nucleotide loop of cobalamin; O'Toole GA et al.; We report the identification of a new locus, designated cobC, involved in the assembly of the nucleotide loop of cobalamin in Salmonella typhimurium . The cobC gene has been mapped, cloned, and sequenced . DNA sequence analysis suggested that cobC is divergently transcribed from the adjacent cobD gene and suggests that the regulatory region of these genes overlap . The cobC gene codes for a predicted polypeptide of 26 kDa with striking homology to phosphoglycerate mutase, fructose-2,6-bisphosphatase, and acid phosphatase enzymes . In vitro experiments demonstrated that CobC dephosphorylated the cobalamin biosynthetic intermediate N1-(5-phospho-alpha-D-ribosyl)-5,6-dimethylbenzimidazole to generate N1-alpha-D-ribosyl-5,6-dimethylbenzimidazole . In vivo data showed that the lack of cobC function blocks the synthesis of cobalamin from its precursors cobinamide and 5,6-dimethylbenzimidazole, i.e . it prevents the assembly of the nucleotide loop of cobalamin . Additionally, exogenous N1-alpha-D-ribosyl-5,6-dimethylbenzimidazole rescues the defect of a cobC mutant . We propose that cobC codes for a novel phosphatase whose primary role is in cobalamin biosynthesis . A model for the sequence of biosynthetic steps that assemble the nucleotide loop of cobalamin in S . typhimurium is presented. J Biol Chem, 1994 Oct 21, 269(42), 26358 - 62 Signal transduction in chemotaxis . A propagating conformation change upon phosphorylation of CheY; Lowry DF et al.; The CheY protein from Escherichia coli and Salmonella typhimurium are among the best characterized proteins of the receiver domain family of two component signal transduction systems in bacteria . Phosphorylation of CheY plays a central role in bacterial chemotaxis . However, it is not entirely clear how its state of phosphorylation contributes to its function . Genetic evidence suggests that CheY changes its conformation upon phosphorylation . We present evidence for this conformation change by comparing the NMR 15N-1H correlation spectra of CheY.Mg2+ complex and phospho-CheY in the presence of magnesium . Large changes in chemical shift are used as indicators of chemical changes and probable structural changes in the protein backbone . Our observations suggest that significant structural changes occur in CheY upon phosphorylation and that these changes are distinct from the changes produced by magnesium ion binding . In addition to residues Asn-59 and Gly-65 that are immediately adjacent to the site of phosphorylation at Asp-57, a large number of other residues show significant chemical shift changes as a result of phosphorylation . These include Met-17, Val-21, Asn-23, Gly-39, Met-60, Met-63, Asp-64, Leu-66, Glu-67, Leu-68, Leu-69, Met-85, Val-86, Thr-87, Ala-88, Asn-94, Val-107, Lys-109, Thr-112, Ala-113, Ala-114, and Asn-121 . These results appear inconsistent with the recent suggestion that phosphorylation produces the same structural changes as magnesium binding (Bellsolell, L., Prieto, J., Serrano, L., and Coll, M . (1994) J . Mol . Biol . 238, 489-495) . We find that some regions change overlap with a genetically defined motor binding face . We therefore propose that the conformation switch modulates the interaction of CheY with its target, the flagellar motor . Other regions also change, possibly reflecting the many different functions of CheY homologues. Commun Dis Rep CDR Rev, 1994 Oct 14, 4(11), R136 - 40 Associations between human and farm animal infections with Salmonella typhimurium DT104 in Herefordshire; Fone DL et al.; Reports of human infection with Salmonella typhimurium definitive type (DT) 104 have generated considerable interest . We undertook a descriptive study of infections with S . typhimurium DT 104 infection in humans and farm animals in Herefordshire between 1991 and 1993 . Laboratory reports of human salmonellosis, sent to the consultant in communicable disease control, were compared with cases identified using Statutory Incident Reports of salmonella in animals, birds and their products, received from the Ministry of Agriculture, Fisheries and Food . Six separate associations of infection between farming families and their livestock were identified . Nine out of 23 human cases, including three family outbreaks, were associated with animal infection . This study suggests that occupationally acquired infection in farmers and their families may be contributing to the national increase in cases, and shows the value of drawing together data from human and animal sources for the surveillance, investigation, and control of human infection with S . typhimurium DT104. Commun Dis Rep CDR Rev, 1994 Oct 14, 4(11), R130 - 5 A case control study of infection with an epidemic strain of multiresistant Salmonella typhimurium DT104 in England and Wales; Wall PG et al.; Laboratory reports of a multiresistant strain of Salmonella typhimurium definitive type (DT) 104 rose in 1993; this led the Public Health Laboratory Service to investigate cases and identify possible risk factors for infection . Information derived from questionnaires, and details of previous isolations of S . typhimurium DT104 from food and animals, were used to design an unmatched case control study . Eighty-three cases whose isolations were of the same plasmid profile type (the 'epidemic strain') and 235 controls were included in the analysis . Illness was independently associated with the consumption of several food items and contact with animals, particularly ill farm animals . The number of isolations of this organism continues to rise, and control measures may include reducing infection in animals used for food, reducing the risk of contamination at all stages of the food chain, and raising awareness of measures to prevent food poisoning among food handlers and the general public. Gene, 1994 Oct 11, 148(1), 173 - 4 The methyl viologen-resistance-encoding gene smvA of Salmonella typhimurium; Hongo E et al.; The complete nucleotide sequence of the gene encoding the Salmonella typhimurium methyl viologen-resistant protein, SmvA, similar to QacA (resistance to quaternary ammonium ion) of Staphylococcus aureus, and the surrounding sequences were determined . This indicated that the gene arrangement of S . typhimurium is different from that of Escherichia coli in this region. EMBO J, 1994 Oct 3, 13(19), 4568 - 76 Genetic and molecular analyses of the interaction between the flagellum-specific sigma and anti-sigma factors in Salmonella typhimurium; Kutsukake K et al.; More than 50 genes are required for flagellar formation and function in Salmonella typhimurium . According to the cascade model of flagellar regulon, the flagellar operons are divided into three classes, 1, 2, and 3, with respect to transcriptional hierarchy . FliA is an alternative sigma factor specific for transcription of the class 3 operons, while FlgM is an anti-sigma factor which binds to FliA and prevents its association with RNA polymerase core enzyme . In the present study, we isolated a number of fliA mutants in which the altered FliA proteins become insensitive to inhibition by FlgM . Sequence analysis of their mutation sites revealed that most of them caused the amino acid substitutions in region 4 of the conserved amino acid sequences of sigma factors which lies near the C-terminal end of FliA . Using a set of fliA deletion mutants in a high-expression plasmid, we demonstrated that polypeptides containing the C-terminal portion of FliA could titrate the intracellular FlgM protein resulting in derepression of the class 3 operons . This result indicates that the C-terminal region of FliA contains the FlgM-binding domain . This was confirmed by a chemical cross-linking experiment with FlgM and truncated FliA proteins. Chem Biol Interact, 1994 Oct, 93(1), 73 - 84 Mutagenic activity of halogenated propanes and propenes: effect of bromine and chlorine positioning; Lag M et al.; A series of halogenated propanes and propenes were studied for mutagenic effects in Salmonella typhimurium TA100 in the absence or presence of NADPH plus liver microsomes from phenobarbital-induced rats as an exogenous metabolism system . The cytotoxic and mutagenic effects of the halogenated propane 1,2-dibromo-3-chloropropane (DBCP) has previously been studied in our laboratories . These studies showed that metabolic activation of DBCP was required to exert its detrimental effects . All of the trihalogenated propane analogues were mutagenic when the microsomal activation system was included . The highest mutagenic activity was obtained with 1,2,3-tribromopropane, with approximately 50-fold higher activity than the least mutagenic trihalogenated propane, 1,2,3-trichloropropane . The order of mutagenicity was as follows: 1,2,3-tribromopropane > or = 1,2-dibromo- 3-chloropropane > 1,3-dibromo-2-chloropropane > or = 1,3-dichlo