J Biol Chem, 1990 Jun 25, 265(18), 10535 - 40 Alkyl hydroperoxide reductase from Salmonella typhimurium . Sequence and homology to thioredoxin reductase and other flavoprotein disulfide oxidoreductases; Tartaglia LA et al.; The DNA sequence of the Salmonella typhimurium ahp locus was determined . The locus was found to contain two genes that encode the two proteins (C22 and F52a) that comprise the S . typhimurium alkyl hydroperoxide reductase activity . The predicted sequence of the F52a protein component of the alkyl hydroperoxide reductase was found to be highly homologous to the Escherichia coli thioredoxin reductase protein (34% identity with many conservative substitutions) . The homology was found to be particularly striking in the region containing the redox-active cysteines of the thioredoxin reductase molecule, and among the identities were the redox-active cysteines themselves . Aside from the strong similarity to thioredoxin reductase, overall homology between the F52a protein and other flavoprotein disulfide oxidoreductases such as glutathione reductase, dihydrolipoamide dehydrogenase, and mercuric reductase was found to be rather limited, and the conserved active site segment common to the three proteins was not observed within the F52a protein . However, three short segments that have been implicated in FAD and NAD binding were found to be conserved between the F52a protein and the other disulfide reductases . These results suggest that the alkyl hydroperoxide reductase is the second known member of a class of disulfide oxidoreductases which was represented previously by thioredoxin reductase alone; they also allow the putative assignment of several functional domains. Mol Cell Biochem, 1990 Jun 25, 95(2), 133 - 7 Nifedipine administration impairs natural resistance of mice to Salmonella typhimurium; Nalini K et al.; Administration of Ca2+ channel blockers in cardiac disorders and the central role of Ca2+ in modulating neutrophil functions, prompted us to investigate whether administration of nifedipine to mice would alter their natural resistance to infectious agents like Salmonella typhimurium . Neutrophil chemiluminescence (CL) in response to S . typhimurium was significantly (p less than 0.01) decreased in mice fed with nifedipine (0.015 mg/kg body weight) over a period of six months . Intracellular killing of S . typhimurium by isolated neutrophils also decreased significantly (p less than 0.01) and exponentially with nifedipine administration, representing a 42% fall at six months . In addition the drug administration lowered the survival rate of animals following challenge by a lethal dose of S . typhimurium (LD50 = 1 x 10(4) bacteria/animal) . Our data suggest that long term administration of nifedipine lowers the natural resistance of mice to S . typhimurium owing to impaired neutrophil functions. J Mol Biol, 1990 Jun 20, 213(4), 819 - 32 Flagellar hook and hook-associated proteins of Salmonella typhimurium and their relationship to other axial components of the flagellum; Homma M et al.; Within the bacterial flagellum the basal-body rod, the hook, the hook-associated proteins (HAPs), and the helical filament constitute an axial substructure whose elements share structural features and a common export pathway . We present here the amino acid sequences of the hook protein and the three HAPs of Salmonella typhimurium, as deduced from the DNA sequences of their structural genes (flgE, flgK, flgL and fliD, respectively) . We compared these sequences with each other and with those for the filament protein (flagellin) and four rod proteins, which have been described previously (Joys, 1985; Homma et al., 1990; Smith & Selander, 1990) . Hook protein most strongly resembled the distal rod protein (FlgG) and the proximal HAP (HAP1), which are thought to be attached to the proximal and distal ends of the hook, respectively; the similarities were most pronounced near the N and C termini . Hook protein and flagellin, which occupy virtually identical helical lattices, did not resemble each other strongly but showed some limited similarities near their termini . HAP3 and HAP2, which form the proximal and distal boundaries of the filament, showed few similarities to flagellin, each other, or the other axial proteins . With the exceptions of the N-terminal region of HAP2, and the C-terminal region of flagellin, proline residues were absent from the terminal regions of the axial proteins . Moreover, with the exception of the N-terminal region of HAP2, the terminal regions contained hydrophobic residues at intervals of seven residues . Together, these observations suggest that the axial proteins may have amphipathic alpha-helical structure at their N and C termini . In the case of the filament and the hook, the terminal regions are believed to be responsible for the quaternary interactions between subunits . We suggest that this is likely to be true of the other axial structures as well, and specifically that interaction between N-terminal and C-terminal alpha-helices may be important in the formation of the axial structures of the flagellum . Although consensus sequences were noted among some of the proteins, such as the rod, hook and HAP1, no consensus extended to the entire set of axial proteins . Thus the basis for recognition of a protein for export by the flagellum-specific pathway remains to be identified. J Mol Biol, 1990 Jun 20, 213(4), 687 - 703 Structure and evolution of a multidomain multiphosphoryl transfer protein . Nucleotide sequence of the fruB(HI) gene in Rhodobacter capsulatus and comparisons with homologous genes from other organisms; Wu LF et al.; The gene order of the fructose (fru) operon and nucleotide sequence of the first gene (fruB(HI) of Rhodobacter capsulatus are reported, analyzed and compared with homologous genes from other bacteria, and the gene products are identified . Included within the region reported is a gene encoding a multiphosphoryl transfer protein (MTP) of the phosphoenolpyruvate:sugar phosphotransferase system (PTS) . MTP consists of three moieties: a fructose-specific enzyme III (IIIfru)-like N-terminal moiety (residues 1 to 143) followed by an FPr(HPr)-like moiety (residues 157 to 245) and an enzyme I-like moiety (residues 273 to 827) . The enzyme III-like moiety closely resembles the N-terminal 143 residues of the IIIfru-FPR fusion protein from Salmonella typhimurium (40.6% identity throughout its length) and the C-terminal 145 residues of the mannitol-specific enzyme II (IImtl) (37.8% identity throughout its length with the IIImtl moiety of IImtl) . The FPr-like domain of MTP resembles the S . typhimurium FPr (42.4% identity) and the Escherichia coli or S . typhimurium HPr (38.8% identity) . The enzyme I-like moiety resembles the E . coli enzyme I (38.9% identity) . Predicted phosphorylation sites within the three functional units of MTP (His62 in the IIIfru-like moiety; His171 in the FPr-like moiety and His457 in the enzyme I-like moiety) were identified on the basis of sequence comparisons with the homologous proteins from enteric bacteria . The three functional domains of MTP are joined by two flexible "linkage" regions, rich in alanine, glycine and proline, which show 47% sequence identity with each other . They also exhibit a high degree of sequence identity with the linkage region of the mannose-specific enzyme III (IIIman) of the E . coli PTS as well as several other proteins of bacterial, eukaryotic and viral origin . At the RNA level, these linker regions formed hairpin structures with high (90%) G + C content . Analyses of the IIIfru-FPr fusion protein of S . typhimurium revealed that between the IIIfru and FPr moieties of this protein is a stretch of 142 amino acids that do not show homology to known PTS proteins . This region and the adjacent FPr-like region contain a sequence of 110 residues exhibiting 59% similarity to the receiver consensus motif defined by Kofoid and Parkinson . Because the Salmonella IIIfru-FPr fusion protein has been implicated in transcriptional regulation, this region of the Salmonella protein may prove to have regulatory significance.(ABSTRACT TRUNCATED AT 400 WORDS) Biochemistry, 1990 Jun 19, 29(24), 5767 - 75 Rotational resonance determination of the structure of an enzyme-inhibitor complex: phosphorylation of an (aminoalkyl)phosphinate inhibitor of D-alanyl-D-alanine ligase by ATP; McDermott AE et al.; We have used a newly developed solid-state NMR method, rotational resonance, to establish the structure of an inhibited complex formed upon reaction of D-alanyl-D-alanine ligase, ATP, and the aminoalkyl dipeptide analogue {1(S)-aminoethyl}{2-carboxy-2(R)-methyl-1- ethyl}phosphinic acid (Ib) . Analogue Ib was determined to be an ATP-dependent, slow-binding inhibitor of the D-Ala-D-Ala ligase from Salmonella typhimurium, with an enzyme-inhibitor half-life of 17 days at 37 degrees C . The inhibited complex shows a 31P NMR spectrum which is very different from that which would arise from a mixture of the free inhibitor and ATP . Four well-resolved lines were observed: two (at -8 and -14 ppm) are assignable as the phosphates of ADP, the third is assignable to an inhibitor resonance (at 53 ppm) that shifts by approximately 19 ppm on binding, and the fourth is assignable to a resonance (at -3 ppm) due to a polyphosphate or phosphate ester moiety . At rotational resonance the spectrum shows evidence for strong dipolar couplings between the phosphinate phosphorus and a phosphate ester species . The dipolar coupling between the phosphorus signals at 53 and -3 ppm was measured at rotational resonance by use of numerical simulations of both the line shape of the signal and the profile of magnetization transfer between the two sites . The measured coupling, 1.0 +/- 0.2 kHz, indicates that the two species are bridged in a P-O-P linkage, with a P-P through-space distance of 2.7 +/- 0.2 A . This proves that the mechanism of inactivation involves phosphorylation of the enzyme-bound inhibitor by ATP to form a phosphoryl-phosphinate adduct. J Biol Chem, 1990 Jun 5, 265(16), 8993 - 8 Kinetic evidence for the formation of D-alanyl phosphate in the mechanism of D-alanyl-D-alanine ligase; Mullins LS et al.; The steady state kinetic mechanism, molecular isotope exchange and the positional isotope exchange (PIX) reactions of D-alanyl-D-alanine ligase from Salmonella typhimurium have been studied . The kinetic mechanism has been determined to be ordered Ter-Ter from initial velocity and product inhibition experiments . The first substrate to bind is ATP followed by the addition of 2 mol of D-alanine . Pi is released, and then D-alanyl-D-alanine and ADP dissociate from the enzyme surface . In the reverse direction D-alanyl-D-alanine exhibits complete substrate inhibition (Ki = 1.15 +/- 0.05 mM) by binding to the enzyme-ATP complex . In the presence of D-alanine, D-alanyl-D-alanine ligase catalyzed the positional exchange of the beta,gamma-bridge oxygen in {gamma-18O4}ATP to a beta-nonbridge position . Two possible alternate dead-end substrate analogs, D-2-chloropropionic acid and isobutyric acid, did not induce a positional isotope exchange in {gamma-18O4}ATP . The positional isotope exchange rate is diminished relative to the net substrate turnover as the concentration of D-alanine is increased . This is consistent with the ordered Ter-Ter mechanism as determined by the steady state kinetic experiments . The ratio of the positional isotope exchange rate relative to the net chemical turnover of substrate (Vex/Vchem) approaches a value of 1.4 as the concentration of D-alanine becomes very small . This ratio is 100 times larger than the ratio of the maximal reverse and forward chemical reaction velocities (V2/V1) . This situation is only possible when the reaction mechanism proceeds in two distinct steps and the first step is much faster than the second step . The enzyme was also found to catalyze the molecular isotope exchange of radiolabeled D-alanine with D-alanyl-D-alanine in the presence of phosphate . These results are consistent with the formation of D-alanyl phosphate as a kinetically competent intermediate. FEBS Lett, 1990 Jun 4, 265(1-2), 129 - 32 Evidence for the ability of L10 ribosomal proteins of Salmonella typhimurium and Klebsiella pneumoniae to regulate rplJL gene expression in Escherichia coli; Paton EB et al.; Genes rplJ, coding for ribosomal protein L10 of Salmonella typhimurium and Klebsiella pneumoniae, have been cloned on pUC plasmid . The resultant multicopy recombinant plasmids were detrimental for the growth of normal JM101 E . coli host cells and harmless for the mutant JF3029 host . This negative effect is the evidence for the ability of heterologous L10 proteins to regulate expression of rplJL genes in E . coli . Nucleotide sequence was determined completely for S . typhimurium rplJL' DNA portion and partially for rplJL' genes of K . pneumoniae . According to the nucleotide sequence data obtained three amino acid substitutions differ L10 proteins of S . typhimurium and E . coli and the long range, providing for the coupled translations of L10 and L7/L12 cistrons in E . coli mRNA is also valid for S . typhimurium and K . pneumoniae. Environ Health Perspect, 1990 Jun, 86, 85 - 7 Metabolism and mutagenicity of isoprene; Gervasi PG et al.; Liver microsomes of various rodents (mouse, rat, rabbit, and hamster) metabolize isoprene (2-methyl-1,3-butadiene) to the corresponding monoepoxides 3,4-epoxy-3-methyl-1-butene and 3,4-epoxy-2-methyl-1-butene . 3,4-Epoxy-3-methyl-1-butene (half-life 85 min) was found to be the main metabolite, although the stable 3,4-epoxy-2-methyl-1-butene was also formed (about 14-25% with respect to the main epoxide) . The kinetic constants (Km and Vmax) for the formation of the major epoxide metabolite of isoprene were determined by gas-liquid chromatography . The minor epoxide was further epoxidized to the isoprene dioxide by the microsomes of all rodents studied . The Km and Vmax were determined and phenobarbital was found to be a good inducer for this epoxidation in all species . The mutagenic activity, using Salmonella typhimurium, and the chemical reactivity (alkylating power and half-life) of the epoxide metabolites of isoprene were investigated and compared to those of other structurally related epoxides . Isoprene and the monoepoxide intermediates of the isoprene biotransformation were not mutagenic in Salmonella typhimurium . However, the isoprene dioxide (2-methyl-1,2,3,4-diepoxybutane) was found to be mutagenic and have alkylating power towards nicotinamide, similar to the structurally corresponding 1,2,3,4-diepoxybutane . In conclusion, the metabolism of isoprene does not lead to the formation of mutagenic monoepoxide (in contrast to butadiene) but the formation of mutagenic and presumably carcinogenic isoprene diepoxide is possible, thereby a genotoxic effect of isoprene in rodents or other species cannot be ruled out. Proc Natl Acad Sci U S A, 1990 Jun, 87(11), 4304 - 8 The ability of Salmonella to enter mammalian cells is affected by bacterial growth state; Lee CA et al.; We have examined the effect of different growth conditions on the ability of Salmonella to interact with Madin-Darby canine kidney cells . Two growth conditions that affect the expression of Salmonella adherence and invasiveness have been identified . First, bacteria lose their invasiveness in the stationary phase of growth . Second, bacteria growing in oxygen-limited growth conditions are induced for adherence and invasiveness, whereas those growing aerobically are relatively nonadherent and noninvasive . Salmonella from cultures aerated with gas mixtures containing 0% or 1% oxygen were 6- to 70-fold more adherent and invasive than those from cultures aerated with a gas mixture containing 20% oxygen . The Salmonella typhimurium oxrA gene that is required for the anaerobic induction of many proteins is not involved in the regulation of Salmonella invasiveness . We speculate that oxygen limitation might be an environmental cue that triggers the expression of Salmonella invasiveness within the intestinal lumen and other tissues. Carcinogenesis, 1990 Jun, 11(6), 985 - 9 Differences in conformations of covalent adducts derived from the binding of 5- and 6-methylchrysene diol epoxide stereoisomers to DNA; Geacintov NE et al.; The conformations of adducts derived from the covalent binding of four different isomeric diol epoxide derivatives of 5- or 6-methylchrysene to native double-stranded calf thymus DNA were studied by linear dichroism techniques . Out of four isomers investigated here, only the R,S,S,R enantiomer of anti-1,2-dihydroxy-3,4-epoxy-1,2,3,4-tetrahydro-5-methylchrysene, (+)-5-MeCDE, is highly tumorigenic and mutagenic toward Salmonella typhimurium TA100; the S,R,R,S enantiomer, (-)-5-MeCDE, and the corresponding R,S,S,R and S,R,R,S enantiomers of anti-1,2,-dihydroxy-3,4-epoxy-1,2,3,4-tetrahydro-6-methylchrysene are non-tumorigenic and much less mutagenic than (+)-5-MeCDE . {Melikian et al., (1988) Cancer Res., 48, 1781-1787} Only the DNA adducts derived from the binding of (+)-5-MeCDE are characterized by a pronounced positive linear dichroism signal at 308 nm due to the phenanthrenyl residue which is tilted at an angle of 45-48 degrees with respect to the average orientations of the axes of unoriented DNA segments . The phenanthrenyl residues derived from the covalent binding to DNA of the other three inactive or less active isomers appear to be unoriented . The defined orientation of the covalently bound phenanthrenyl residues derived from (+)-5-MeCDE corresponds to adduct conformations which are similar to those obtained from the binding of the highly tumorigenic trans-7,8-dihydroxy-anti-9,10-epoxy-7,8,9,10-tetrahydrobenzo{a}pyrene stereoisomer and other highly active bay-region diol epoxide derivatives to DNA . These findings provide further evidence that there is a correlation between DNA adduct conformation and biological activities for these series of polycyclic aromatic diol epoxide derivatives with R,S,S,R absolute configuration and which are known to bind predominantly to N2 of guanine. Infect Immun, 1990 Jun, 58(6), 1711 - 9 The Borrelia burgdorferi flagellum-associated 41-kilodalton antigen (flagellin): molecular cloning, expression, and amplification of the gene; Wallich R et al.; Monoclonal antibodies directed against the major Borrelia burgdorferi flagellar protein, the 41-kilodalton (kDa) protein flagellin, were used to monitor cloning and expression of the flagellin gene from a Borrelia burgdorferi genomic library . The structure of the gene was analyzed, and recombinant nonfusion flagellin was produced in Escherichia coli . A DNA sequence analysis of the 41-kDa flagellin gene revealed the presence of an open reading frame that encoded a protein having 336 amino acid residues and a calculated molecular mass of 35.8 kDa, indicating that there was posttranslational modification of the natural 41-kDa flagellin protein . Upstream from the AUG start codon sequence we identified motifs corresponding to consensus procaryotic promoter elements which could be utilized by the cloned flagellin gene when it was expressed in E . coli MC1061 . The deduced flagellin protein sequence exhibited high levels of homology to sequences of flagellin proteins from Bacillus subtilis and Salmonella typhimurium . The levels of sequence similarity for the amino- and carboxy-terminal portions were about 65 and 56%, respectively . DNA sequence information on the flagellin gene was used to design oligonucleotides for gene amplification by the polymerase chain reaction method, and by using this method 0.01 pg of Borrelia burgdorferi DNA could be detected . Our results provide a basis for further biochemical analysis of the 41-kDa flagellin protein, investigation of the role of this protein in host-pathogen interactions, and development of a standardized reagent for diagnostic systems for Borrelia burgdorferi infections. J S Afr Vet Assoc, 1990 Jun, 61(2), 65 - 7 Salmonellosis in an adult dairy cow; Stadler P et al.; An outbreak of diarrhoea occurred in a Jersey herd after the introduction of new stock . One of the cows was examined and treated unsuccessfully . Clinical findings included depression, fever, dehydration, congestion, signs of colic and a severe diarrhoea . The post mortem examination revealed emaciation, pseudomembranous enteritis, mesenteric lymphadenopathy and focal disseminated hepatic necrosis . Salmonella typhimurium was isolated from the faeces, mesenteric lymph nodes and liver. J Toxicol Sci, 1990 Jun, 15 Suppl 2, 239 - 51 Mutagenicity tests of mofezolac (N-22); Ohuchida A et al.; 1 . The reverse mutation test was carried out on mofezolac (N-22) at dose range of 50-5000 micrograms/plate using Salmonella typhimurium strains, TA100, TA98, TA1535 and TA1537, and Escherichia coli strain WP2uvrA . In all tester strains no significant increases were observed in the number of revertant colonies as compared with solvent control in the absence or presence of mammalian metabolic activation system . 2 . The chromosomal aberration test on N-22 was carried out using cultured Chinese hamster lung cells (CHL) . The cells were treated with N-22 at the doses of 37.5, 75.0, 150 and 300 micrograms/ml without S9 Mix and at the doses of 150, 300, 450 and 600 micrograms/ml with S9 Mix . No significant differences were found in the incidence of structural-and numeral-aberrations of chromosomes as compared with the solvent control in the system without S9 Mix . However, in the system with S9 Mix, structural aberration (11.5%) and numeral aberration (14.2%) of chromosomes were observed in the groups of dosing 600 micrograms/ml with dose dependency . 3 . These results indicate that N-22 has clastogenic activity by the metabolic activation. FEMS Microbiol Lett, 1990 Jun 1, 57(3), 205 - 10 sulA-independent division inhibition in his-constitutive strains of Salmonella typhimurium; Gibert I et al.; Constitutive expression of the S . typhimurium histidine operon causes multiple phenotypic changes including strong filamentation . However, the SOS regulatory network is not involved in the inhibition of cell division . The possibility of SOS-independent activation of sulA gene transcription has been ruled out using sulA-lacZ fusions . These results suggest the existence of a pathway of division inhibition unrelated to sulA and not regulated by the SOS system. Kansenshogaku Zasshi, 1990 Jun, 64(6), 693 - 8 {O5-antigenic classification of Salmonella typhimurium isolated from outbreaks of Salmonella enteritis}; Yamaura N et al.; S . typhimurium (STM) were isolated from outbreaks of Salmonella enteritis and were studied for their reactivity to monoclonal antibody TMY1 specific for Salmonella O5-antigen with the following results; By using the bacterial agglutination test with TMY1, STM were classified into O5-antigenic molecule positive and negative (copenhagen type) strains, suggesting the usefulness of TMY1 as an exquisite epidemiologic tool for Salmonella enteritis. Environ Health Perspect, 1990 Jun, 86, 75 - 8 In vitro and in vivo genotoxicity of 1,3-butadiene and metabolites; Arce GT et al.; 1,3-Butadiene and two major genotoxic metabolites 3,4-epoxybutene (EB) and 1,2:3,4-diepoxybutane (DEB) were used as model compounds to determine if genetic toxicity findings in animal and human cells can aid in extrapolating animal toxicity data to man . Sister chromatid exchange (SCE) and micronucleus induction results indicated 1,3-butadiene was genotoxic in the bone marrow of the mouse but not the rat . This paralleled the chronic bioassays which showed mice to be more susceptible than rats to 1,3-butadiene carcinogenicity . However, 1,3-butadiene did not induce unscheduled DNA synthesis (UDS) in the rat or mouse hepatocytes following in vivo exposure . Likewise, UDS in rat and mouse hepatocytes in vitro was not induced by EB or DEB . Salmonella typhimurium gene mutation (Ames) tests of 1,3-butadiene using strains TA1535, TA97, TA98, and TA100 and employing rat, mouse, and human liver S9 metabolic systems were barely 2-fold above background only in strain TA1535 at 30% 1,3-butadiene in air with induced and uninduced rat S9 and mouse S9 (uninduced) . 1,3-Butadiene was negative in in vitro SCE studies in human whole blood lymphocytes cultures treated in the presence of rat, mouse, or human liver S9 metabolic activation . In general, 1,3-butadiene is genotoxic in vivo but is a weak in vitro genotoxin. Mol Biochem Parasitol, 1990 Jun, 41(2), 281 - 8 The gene for hypoxanthine phosphoribosyl transferase of Plasmodium falciparum complements a bacterial HPT mutation; Shahabuddin M et al.; The enzyme hypoxanthine phosphoribosyl transferase of Plasmodium falciparum has been overexpressed in Escherichia coli . The protein was found to be active enzymatically . When the recombinant expression vector (pPfPRT2) was transformed and expressed in a Salmonella typhimurium mutant KP1684 (purE deoD hpt gpt), the active expressed protein complemented the hpt mutation in the bacteria . We discuss the practical value of this strain . Assays of the expressed protein in the mutant extract showed that the enzyme is able to use hypoxanthine, guanine and xanthine as substrates . A specificity study using the competitive inhibitor, 6-thioguanine, showed that of these hypoxanthine is the most favourable substrate . The biological significance of xanthine utilisation by the enzyme is discussed. Appl Environ Microbiol, 1990 Jun, 56(6), 1541 - 6 Enzyme-linked immunosorbent assay for Salmonella typhimurium in food: feasibility of 1-day Salmonella detection; Lee HA et al.; A microtitration plate, antibody-capture, enzyme-linked immunosorbent assay was developed for detection of Salmonella typhimurium . The assay utilizes a monoclonal detector antibody which shows no cross-reactions with non-Salmonella species and only a slight cross-reaction with one other Salmonella serotype . By using only one cultural stage (in a nonselective, chemically defined medium) prior to the enzyme-linked immunosorbent assay, low numbers of cells in food (10 cells 25 g-1) were detected in 19 h . Non-Salmonella competing organisms did not interfere with detection of S . typhimurium even when present in the ratio of 10(6):1 (non-Salmonella/Salmonella spp.) . The assay shows the feasibility of rapid, 1-day testing for Salmonella spp . with antibody technology. Mutat Res, 1990 Jun, 244(2), 129 - 34 Inhibitory action of peony root extract on the mutagenicity of benzo{a}pyrene; Sakai Y et al.; The inhibitory effects of peony root extract on the mutagenicity of benzo{a}pyrene (B {a}p) have been investigated in the Salmonella typhimurium reversion test . Four kinds of experiments were performed: direct chemical reaction (1) between peony root extract and B {a}p, and (2) between peony root extract and active metabolite(s) of B {a}p, (3) inhibition of metabolic processes of B{a}p with S9 mix, and (4) inhibition of activation on mutagenicity . Peony root extract interfered with the action of enzymes in the S9 mix, and inactivated the activity of B{a}p metabolites . The bio-antimutagenic effect was assayed by reversion in Salmonella typhimurium TA98 and TA100. Carcinogenesis, 1990 Jun, 11(6), 975 - 80 Quantitative relationship between mutagenic potency in the Ara test of Salmonella typhimurium and carcinogenic potency in rodents . A study of 11 direct-acting monofunctional alkylating agents; Roldan-Arjona T et al.; This work attempted to derive a quantitative relationship between mutagenicity and carcinogenicity by examining the association between mutagenic potency in the Ara test of Salmonella typhimurium and carcinogenic potency in rodents . Mutagenesis was monitored by selecting forward mutations to L-arabinose resistance . Lethality was measured at equivalent experimental conditions to those of mutant yield by using a mixed population of a pair of isogenic strains distinguished by their differential nutritional requirements . The study was carried out with a group of 11 direct-acting monofunctional alkylating agents, which failed to show any quantitative correlation in the histidine reverse-mutation test . Our data suggest that the mutagenic efficiency of the compounds is directly proportional to the magnitude of the maximum yield of L-arabinose resistance mutants and inversely proportional to the dose and the number of lethal hits at which the maximum yield occurs . A highly significant correlation (r10 = 0.86, P less than 0.01) was found between the mutagenic efficiencies of the compounds in the Ara test and their carcinogenic potencies in rodents, expressed as TD50 ('tumor dose' 50) values . The result suggests that the Ara forward-mutation test of S . typhimurium might be capable of reflecting the relative potency of animal carcinogens, at least when confined to particular chemical classes . A more generic and definitive conclusion about the predictive value of the Ara test would require this analysis to be extended to other types of genotoxic carcinogens. Mutat Res, 1990 Jun, 241(2), 151 - 9 Mutagenicity evaluation of HC Blue No . 1 and HC Blue No . 2 . III . Effects in the Salmonella typhimurium/Escherichia coli reversion assay and the mouse lymphoma L5178Y TK+/- forward mutation assay; Oberly TJ et al.; The hair-dye ingredients, HC Blue No . 1 (HCB1) and HC Blue No . 2 (HCB2), were tested for the induction of bacterial mutation using Salmonella typhimurium strains TA1535, TA1537, TA98 and TA100; and Escherichia coli strains WP2uvrA- . In addition, both dyes were evaluated in the mouse lymphoma L5178Y TK+/- assay (MLA) for the potential to induce forward mutation . A liver homogenate (S9) prepared from Aroclor 1254-induced male Fischer 344 rats was used to provide a means for metabolic activation . HCB1 was not mutagenic in the Ames assay, but was weakly mutagenic in the MLA only in the presence of metabolic activation . In contrast, HCB2 was a strong mutagen in the Ames assay in tester strain TA98 both in the presence and absence of metabolic activation . A positive response was also noted with HCB2 in the MLA, both in the presence and absence of metabolic activation . Negative findings from the Ames assay of this study agree with other published results where an identical lot of HCB1 was used . Using the same lot, a weak positive result was observed in the MLA, however, the activation requirements and magnitude of the response were different from that of a lot evaluated by the NTP . In contrast, HCB2 appears to be both a bacterial and mammalian cell mutagen independent of lot variability. J Bacteriol, 1990 Jun, 172(6), 3358 - 66 Sulfate and thiosulfate transport in Escherichia coli K-12: identification of a gene encoding a novel protein involved in thiosulfate binding; Hryniewicz M et al.; The sequence of 1,973 nucleotides encompassing the region at and directly adjacent to the CysB-dependent promoter controlling expression and synthesis of the sulfate-thiosulfate transport system of Escherichia coli has been determined . The transcription start site has been mapped by primer extension . One open reading frame representing the first gene of the presumed sulfate transport operon was identified and designated cysP . The deduced amino acid sequence of the CysP polypeptide indicates the presence of a signal peptide . Expression of the cysP gene in the T7 promoter-polymerase system revealed the location of the gene product in the periplasm . Construction of a cysP insertional mutant and assays of binding and uptake of sulfate and thiosulfate by this mutant allowed the identification of the cysP gene product as a thiosulfate-binding protein . The TGA termination codon of cysP was found to overlap the putative ATG initiation codon of the next open reading frame, inferred as being essential for the sulfate transport system, and it was designated cysT . Preliminary sequence data from the corresponding region of the Salmonella typhimurium chromosome showed strictly homologous counterparts of the E . coli cysP and cysT genes. Mol Gen Genet, 1990 Jun, 222(1), 161 - 5 Transcription and regulation of the cpdB gene in Escherichia coli K12 and Salmonella typhimurium LT2: evidence for modulation of constitutive promoters by cyclic AMP-CRP complex; Liu J et al.; Measurements of cyclic phosphodiesterase, or of beta-galactosidase in the case of cpdB'-'lacZ fusions, indicate that cpdB expression in both Escherichia coli and Salmonella typhimurium is modulated by carbon source availability, consistent with previous observations in Salmonella . Nucleotide sequence analysis and transcription mapping of both cpdB genes have revealed, in their 5' flanking regions, sequences with good similarity to consensus -10 and -35 regions and cyclic AMP-cyclic AMP receptor protein (cAMP-CRP) binding sites . Furthermore, they are strongly conserved in both organisms . Deletion analysis of an E . coli cpdB'-'lacZ fusion supports the identification of these elements, and a role for the cAMP-CRP binding site in modulating constitutive cyclic phosphodiesterase expression. Proc Natl Acad Sci U S A, 1990 Jun, 87(12), 4790 - 3 Five of 12 forms of vaccinia virus-expressed human hepatic cytochrome P450 metabolically activate aflatoxin B1; Aoyama T et al.; Twelve forms of human hepatic cytochrome P450 were expressed in hepatoma cells by means of recombinant vaccinia viruses . The expressed P450s were analyzed for their abilities to activate the potent hepatocarcinogen aflatoxin B1 to metabolites having mutagenic or DNA-binding properties . Five forms, P450s IA2, IIA3, IIB7, IIIA3, and IIIA4, activated aflatoxin B1 to mutagenic metabolites as assessed by the production of His revertants of Salmonella typhimurium in the Ames test . The same P450s catalyzed conversion of aflatoxin B1 to DNA-bound derivatives as judged by an in situ assay in which the radiolabeled carcinogen was incubated with cells expressing the individual P450 forms . Seven other human P450s, IIC8, IIC9, IID6, IIE1, IIF1, IIIA5, and IVB1, did not significantly activate aflatoxin B1 as measured by both the Ames test and the DNA-binding assay . Moreover, polyclonal anti-rat liver P450 antibodies that crossreact with individual human P450s IA2, IIA3, IIIA3, and IIIA4 each inhibited aflatoxin B1 activation catalyzed by human liver S-9 extracts . Inhibition ranged from as low as 10% with antibody against IIA3 to as high as 65% with antibody against IIIA3 and IIIA4 . These results establish that metabolic activation of aflatoxin B1 in human liver involves the contribution of multiple forms of P450. J Bacteriol, 1990 Jun, 172(6), 2940 - 5 Activation of a new proline transport system in Salmonella typhimurium; Ekena K et al.; Proline uptake can be mediated by three different transport systems in wild-type Salmonella typhimurium: a high-affinity proline transport system encoded by the putP gene and two glycine-betaine transport systems with a low affinity for proline encoded by the proP and proU genes . However, only the PutP permease transports proline well enough t allow growth on proline as a sole carbon or nitrogen source . By selecting for mutations that allow a putP mutant to grow on proline as a sole nitrogen source, we isolated mutants (designated proZ) that appeared to activate a cryptic proline transport system . These mutants enhanced the transport of proline and proline analogs but did not require the function of any of the known proline transport genes . The mutations mapped between 75 and 77.5 min on the S . typhimurium linkage map . Proline transport by the proZ mutants was competitively inhibited by isoleucine and leucine, which suggests that the ProZ phenotype may be due to unusual mutations that alter the substrate specificity of the branched-chain amino acid transport system encoded by the liv genes. Infect Immun, 1990 Jun, 58(6), 1879 - 85 Expression of Salmonella typhimurium genes required for invasion is regulated by changes in DNA supercoiling; Galan JE et al.; The ability to enter intestinal epithelial cells is an essential virulence factor of salmonellae . We have previously cloned a group of genes (invA, B, C, and D) that allow S . typhimurium to penetrate tissue culture cells (J . E . Galan and R . Curtiss III, Proc . Natl . Acad . Sci . USA 86:6383-6387, 1989) . Transcriptional and translational cat and phoA fusions to invA (the proximal gene in the invABC operon) were constructed, and their expression was studied by measuring the levels of alkaline phosphatase or chloramphenicol acetyltransferase activity in mutants grown under different conditions . It was found that when strains containing the fusions were grown on media with high osmolarity, a condition known to increase DNA superhelicity, the level of invA transcription was approximately eightfold higher than that in strains grown on media with low osmolarity . The osmoinducibility of invA was independent of ompR, which controls the osmoinducibility of other genes . Strains grown in high-osmolarity media in the presence of subinhibitory concentrations of gyrase inhibitors (novobiocin or coumermycin A1), which reduce the level of DNA supercoiling, showed reduced expression of invA . Nevertheless, invA was poorly expressed in topA mutants of S . typhimurium, which have increased DNA superhelicity . In all cases, the differential expression of the invasion genes was correlated with the ability of S . typhimurium to penetrate tissue culture cells . These results taken together indicate that expression of S . typhimurium invasion genes is affected by changes in DNA supercoiling and suggest that this may represent a way in which this organism regulates the expression of these genes. Ann Otol Rhinol Laryngol Suppl, 1990 Jun, 148, 33 - 4 Role of middle ear endotoxin in inner ear inflammatory response and hydrops: long-term study; Lim DJ et al.; The permeability of the round window membrane for Salmonella typhimurium-derived endotoxin was examined with use of a total of 33 chinchillas . One milligram of each endotoxin was instilled into the tympanic cavities via the superior bullae . The endotoxin activities in middle ear effusions (MEEs), perilymph, and sera were determined by limulus amebocyte lysate assay . Endotoxin was detected in perilymph on the inoculated side by 12 hours after endotoxin instillation and persisted for up to 3 weeks . Endotoxin level peaked at 24 to 48 hours postinstillation, and it steadily declined afterward . This result suggests that the maximum penetration occurred during the active inflammatory stage . Histologic evidence demonstrated remarkable pathologic changes in the inner ear, including bleeding and inflammatory cell recruitment, mostly in the perilymphatic spaces (eg, scalae tympani, scalae vestibuli, spiral ligament), strial swelling, and sensory cell degeneration . This result suggests that endotoxin present in the middle ear can permeate the round window membrane, causing inner ear tissue damage in this animal model. J Immunol, 1990 Jun 1, 144(11), 4340 - 6 Activation of mouse peritoneal macrophages during infection with Salmonella typhimurium does not result in enhanced intracellular killing; Langermans JA et al.; Our study was performed to investigate whether macrophages become activated during an infection with Salmonella typhimurium and, if so, whether these activated macrophages kill S . typhimurium faster than resident macrophages . Mice received i.v . injections with a sublethal number of S . typhimurium; on about day 12 of the infection the numbers of bacteria in the liver and the spleen were maximal . During the infection, activation of peritoneal macrophages could be demonstrated on the basis of three criteria, i.e., the ability to inhibit the proliferation of Toxoplasma gondii, an enhanced production of H2O2 and an increased expression of Ia Ag . The rate of in vitro intracellular killing of S . typhimurium by these activated macrophages was not increased compared to that for resident macrophages . To determine the growth of S . typhimurium in activated mice a nalidixic acid-resistant mutant strain, called S . typhimurium 510R, was used . The net growth rates of the mutant S . typhimurium 510R in the spleen of S . typhimurium 510-activated and normal mice were similar . However, in the liver of S . typhimurium 510-activated mice the number of S . typhimurium 510R did not change during 3 to 48 h after injection . The role of specific antibodies during the initial phase of the infection was negligible, because only low levels of antibodies were detected during the first 15 days of infection and the growth rates of S . typhimurium 510 in the spleen and liver of mice with high titers of antibodies were not significantly different from the rates in normal mice . The results of this study demonstrate that although macrophages become activated during an infection with S . typhimurium, these cells do not display an enhanced bactericidal activity in vitro and in vivo no significant effect on the growth rate of S . typhimurium in the spleen and a bacteriostatic effect in the liver is found . Hence macrophage activation is probably not very important in the host defense against S . typhimurium. Infect Immun, 1990 Jun, 58(6), 2014 - 6 Anaerobiosis, type 1 fimbriae, and growth phase are factors that affect invasion of HEp-2 cells by Salmonella typhimurium; Ernst RK et al.; The invasion of HEp-2 cells by Salmonella typhimurium was studied under various conditions . Anaerobiosis was shown to markedly affect the internalization of bacterial cells by HEp-2 cells . Anaerobically grown bacteria incubated with HEp-2 cells under anaerobic conditions markedly stimulated the rate of invasion . Anaerobiosis may therefore be a controlling factor in the invasion process . Cells obtained during the logarithmic phase of growth invaded at much higher rates than cells obtained during the stationary phase of growth . The presence of mannose-sensitive type 1 fimbriae on the bacterial surface also promoted invasion, and these fimbriae appear to play a role as an accessory virulence factor. Zentralbl Bakteriol, 1990 Jun, 273(2), 200 - 8 Macrophage activation by leptospiral lipopolysaccharide; Isogai E et al.; Leptospiral lipopolysaccharides (LPSs) extracted from Leptospira interrogans serovars copenhageni and hebdomadis were tested for the ability to induce macrophage activation . In-vitro analysis showed that each leptospiral LPS was a potent activator to macrophages . After stimulation with the LPSs, interleukin-1 (IL-1) secretion, interferon (IFN) production and chemiluminescence (CL) response were induced . Intravenous high-dose injection of the leptospiral LPSs induced various lesions such as necrosis of the liver, and the LPSs were detected in macrophages in the liver, spleen and lymphnodes by immunohistochemical examination . Enhancement of macrophage activity in mice inoculated with low doses of leptospiral LPS was recognized . The macrophages of the LPS-treated mice showed a significantly higher bactericidal action than those of control mice . The beta-galactosidase and nitroblue tetrazolium (NBT) positive cells in macrophages of the LPS-treated mice increased significantly . In the NBT reduction test after phagocytosis of latex beads or Salmonella typhimurium, the macrophages of the LPS-treated mice showed a significantly higher activity than those of control mice. J Immunol Methods, 1990 May 25, 129(2), 221 - 6 Cross-reactive affinity purification of immunoglobulin recognizing common gram-negative bacterial core antigens; Tyler JW et al.; A procedure isolating immunoglobulins specific for common gram-negative bacterial core antigens is described . A polyclonal reagent was purified by ammonium sulfate precipitation, dialysis, and column affinity chromatography . The initial vaccinal antigen was an Ra mutant Escherichia coli O111:B4 (strain J5) . The capture antigen was lipopolysaccharide derived from an Ra mutant, Salmonella typhimurium TV119 covalently-linked to an agarose matrix . Column eluants were characterized in terms of total protein concentration, IgG concentration, and EIA titer recognizing E . coli (J5) . Low protein, low IgG, high EIA reading fractions were isolated, demonstrating the utility of the described technique to purify broad spectrum cross-reactive immunoglobulin reagents. J Biol Chem, 1990 May 25, 265(15), 8387 - 91 Identification of the polyamine-induced protein as a periplasmic oligopeptide binding protein; Kashiwagi K et al.; The physiological function of the polyamine-induced protein (PI protein), whose synthesis is stimulated at an early stage after the addition of putrescine to growing cells of a polyamine-requiring mutant of Escherichia coli (Mitsui, K., Igarashi, K., Kakegawa, T., and Hirose, S . (1984) Biochemistry 23, 2679-2683), has been studied . The following findings clearly show that the PI protein is a binding protein of an oligopeptide transport system . (a) PI protein was found in a periplasmic fraction . (b) When the restriction map of a clone for the PI protein gene was compared with Kohara's physical map (Kohara, Y., Akiyama, K., and Isono, K . (1987) Cell 50, 495-508), the gene was found at 27 min of the E . coli chromosome, where genes for an oligopeptide transport system were located . (c) The clone contained a 1,629-nucleotide open reading frame encoding a 543-amino acid protein whose calculated Mr was 60,901, and the predicted amino acid sequence from this open reading frame was quite similar to that of an oligopeptide binding protein of Salmonella typhimurium . (d) When the transport activity of a tripeptide, Gly-Leu-125I-Tyr, was measured in a polyamine-requiring mutant of E . coli growing both in the presence and absence of putrescine, the activity was higher in the cells growing in its presence . (e) Polyamine stimulation of cell growth was greater when an oligopeptide rather than corresponding amino acids was added to the medium . These results suggest that the polyamine stimulation of PI protein synthesis at the early stage after the addition of putrescine contributes to the polyamine stimulation of cell growth through the supply of nutrients. J Biol Chem, 1990 May 15, 265(14), 8108 - 16 Structural characterization of monophosphoryl lipid A homologs obtained from Salmonella minnesota Re595 lipopolysaccharide; Johnson RS et al.; Sixteen monophosphoryl Lipid A (MLA) homologs obtained from the lipopolysaccharides of Salmonella minnesota Re595 were separated by preparative thin layer chromatography into eight fractions . The components of these fractions were analyzed directly (or as structural analogs) and characterized by mass spectrometry . Molecular weights were determined by negative and positive ion fast atom bombardment mass spectrometry and component structures were assigned following a study of fragmentation and metastable ion kinetic energy spectrometry . One fraction (TLC-8) contained a single heptaacyl MLA of Mr = 1,954, a structure previously elucidated (Qureshi, N., Mascagni, P., Ribi, E., and Takayama, K . (1985) J . Biol . Chem . 260, 5271-5278) . The remaining seven fractions contained 15 additional MLAs with decreasing acylation . Two of these components have been previously reported in S . minnesota and Salmonella typhimurium . Three of the eight TLC fractions (TLC-8, -7, -6) were found to be biologically active toward human platelets inducing their aggregation and secretion of serotonin . All tested fractions induced varying degrees of phosphorylation of a platelet protein of Mr = 47,000 (P47) reflecting protein kinase C activation (Grabarek, J., Her, G . R., Reinhold, V . N., and Hawiger, J . J . (1990) J . Biol . Chem . 265, 8117-8121). Ugeskr Laeger, 1990 May 14, 152(20), 1456 - 7 {Salmonella typhimurium meningitis during the neonatal period}; Rix M et al.; Salmonella meningitis is rare . A case of Salmonella typhimurium meningitis in an infant aged eight days is presented . The infant was probably infected during delivery . The infant survived with severe neurological sequelae . Recurrence of excretion of Salmonella typhimurium in the faeces occurred after withdrawal of antibiotic therapy and, after nine months, Salmonella typhimurium was still excreted in the faeces. Vet Rec, 1990 May 12, 126(19), 479 - 81 Diarrhoea in adult horses: a survey of clinical cases and an assessment of some prognostic indices; Mair TS et al.; Samples of faeces and blood were obtained from 66 adult horses with diarrhoea . The results of routine bacteriological, parasitological, haematological and biochemical tests were correlated with the outcome of the cases . Twenty-two (33 per cent) of the horses died or were destroyed as a consequence of the diarrhoea . A diagnosis was reached in only 23 cases (35 per cent), and in nine of them only at post mortem examination . Salmonella typhimurium was isolated from five cases . Statistical analysis revealed significant differences between the horses which survived and those which died in their packed cell volumes, white blood cell counts, neutrophil counts, serum albumin concentrations and alkaline phosphatase activities. Mutagenesis, 1990 May, 5(3), 233 - 9 Relationship of Syrian inbred hamster acetylator genotype to the mutagenic activation of 2-aminofluorene; Yerokun T et al.; The genetic constitution of mammalian enzymes involved in the metabolism of xenobiotics is one of the important factors responsible for large inter-individual differences in the rate of biotransformation and consequently the magnitude of genotoxic effects exerted in target tissues . The present study examines the mutagenic activation of 2-aminofluorene (AF) with hepatic post-mitochondrial (S9) preparations derived from homozygous rapid (Patr/Patr) acetylator and homozygous slow (Pats/Pats) acetylator Syrian inbred hamsters and its relationship to acetylator genotype . These hamster strains differ in their capacities for acetyl coenzyme A (AcCoA)-dependent, N-acetylation and O-acetylation of carcinogenic arylamines and their N-hydroxyarylamine metabolites . AF N-acetyltransferase activities determined in hepatic S9 fractions were 72.2 +/- 4.2 nmol/min/mg in rapid acetylator hamsters and 6.65 +/- 0.37 nmol/min/mg in slow acetylators, and were unaffected by the presence of 0.1 mM paraoxon . Mutagenic activation of AF was measured by reversion to histidine prototrophy in Salmonella typhimurium strain TA98 . The metabolic activation of AF utilizing standard hepatic S9 preparations exhibited typical saturation kinetics that did not differ between acetylator genotypes . However, the addition of AcCoA to the standard S9 mix resulted in a dose-dependent reduction in the number of histidine revertants . In dose-response studies in which the concentrations of AF, AcCoA or S9 protein were varied, higher numbers of revertants were consistently generated with hepatic S9 derived from the slow acetylator compared to the rapid acetylator hamsters . These results indicate an acetylator genotype-dependent modulation of arylamine genotoxicity was reflected as a reduction in the levels of mutagenic metabolites generated in vitro.(ABSTRACT TRUNCATED AT 250 WORDS) FEMS Microbiol Lett, 1990 May, 57(1-2), 1 - 6 Evidence for a DNA inversion system in Bordetella pertussis; Foxall PA et al.; The expression of virulence-associated genes in Bordetella pertussis can be lost in three ways: phase variation, antigenic modulation, or serotype conversion . The mechanism(s) of these alterations in gene expression is unclear . B . pertussis chromosomal DNA was probed with cloned pin genes from Escherichia coli and cloned hin genes from Salmonella typhimurium . DNA duplex melting temperature experiments indicated significant homology between B . Pertussis chromosomal DNA and both DNA inversion genes . Southern blots using the hin gene probe showed homology with a 15 kb EcoRI fragment of B . pertussis chromosomal DNA . We postulate here that B . pertussis contains a DNA inversion system which may be responsible for serotype conversion or virulence phase change in this organism. Poult Sci, 1990 May, 69(5), 818 - 26 Effects of a buffered propionic acid in diets on the performance of broiler chickens and on microflora of the intestine and carcass; Izat AL et al.; A buffered propionic acid (BPA) was added to broiler diets fed in floor pens with litter . The BPA was fed continuously at 0, .2, .4, and .8% in Trial 1 and at 0 and .4% in Trial 2 . The BPA was also fed at .4% for the last 7 days in Trial 2 . Natural salmonellae exposure versus periodic dosage with Salmonella typhimurium was compared in Trial 2 . In Trial 1, the BPA supplement had no adverse effects on growth, feed utilization, or abdominal fat with a significant (P less than or equal to .05) increase in the female dressing value at .8% of buffered propionic acid . The total number of coliforms and of Escherichia coli in the duodenum were significantly reduced by .4% BPA; in the jejunum, by all levels used in the trials; and in the ileum, by .4% and .8% of buffered propionic acid . The intestinal pH was not influenced by the BPA addition . In Trial 2, the BPA at .4% fed continuously had no adverse effect on growth, feed utilization, the abdominal fat of females, or the dressing percentage of males while significantly reducing the abdominal fat for males and increasing the dressing percentage for females . Feeding .4% BPA for the last 7 days had no effect on any of these parameters . Periodic dosage with S . typhimurium had no effect on body weight, feed utilization, or abdominal fat and significantly increased the dressing percentage . There was a significant interaction between the Salmonella dosage and the time of feeding BPA on dressing percentage.(ABSTRACT TRUNCATED AT 250 WORDS) Toxicol Lett, 1990 May, 51(3), 277 - 85 Release of mutagens after chemical or microbial degradation of beech wood lignin; Mohtashamipur E et al.; The microbial or chemical degradation of lignin from untreated samples of beech wood dusts (Fagus silvatica) resulted in the release of different mutagenic responses in the Salmonella/mammalian plate incorporation assay . In the first experiment using chemical degradation of lignin, dust samples were pre-extracted using acetone-water; the lignin portions were degraded into simpler compounds which were further fractionated on a Sephadex-LH20 column . The compounds isolated from the second phase of Sephadex, representing substances with a 3-4 ring structure and/or those of the same molecular weight, were highly mutagenic towards Salmonella typhimurium TA100 in the presence of metabolic activation . These substances were also active to some extent in strain TA1537 both in the presence and absence of Aroclor-induced rat liver homogenates . In contrast, no direct- or indirect-acting mutagenicity was found when testing with strains TA97 and TA98 . Strain TA1535 responded positively only to direct-acting mutagens in the fraction tested . The mutagenic fraction was found to be toxic to the cells when tested in a histidine-rich medium . Repurification of this mutagenic fraction, using silica-gel column chromatography, revealed much higher mutagenic activity than the test material towards strain TA100 . In the second pilot experiment, Phanerochaete chrysosporium and Chaetomium globosum, which are known for their ability to degrade lignin, were each incubated with wood dusts in a mixture of physiological saline and nutrient broth for either 3 or 30 days . Significant mutagenic activity was observed with the dust extract after incubation with Ph . chrysosporium but not with Ch . globosum which is a known degrader of beech lignin . These results are discussed regarding hypotheses on the carcinogenicity of beech wood dusts. Carcinogenesis, 1990 May, 11(5), 869 - 71 Formation of a nitro derivative of 2-amino-3,4-dimethylimidazo{4,5-f}quinoline by photo-irradiation; Hirose M et al.; A direct-acting mutagen to Salmonella typhimurium TA98 was found to be formed by exposing 2-amino-3,4-dimethylimidazo{4,5-f}quinoline (MeIQ) in acetone to sunlight for 60 min . The direct-acting mutagen in the irradiated sample was purified by HPLC and identified as 3,4-dimethyl-2-nitroimidazo-{4,5-f}quinoline (NO2-MeIQ) . The yield of NO2-MeIQ from MeIQ was estimated to be 0.3%. Cancer Res, 1990 May 1, 50(9), 2729 - 33 Androgen-dependent renal microsomal cytochrome P-450 responsible for N-hydroxylation and mutagenic activation of 3-methoxy-4-aminoazobenzene in the BALB/c mouse; Degawa M et al.; A murine renal microsomal enzyme responsible for the mutagenic activation of 3-methoxy-4-aminoazobenzene (3-MeO-AAB) was characterized by its catalytic activity for the mutagenic and metabolic conversion of 3-MeO-AAB . Incubation of 3-MeO-AAB with a renal or hepatic microsome fraction from male BALB/c mice in the presence of NADPH and NADH yielded N-hydroxy and 4'-hydroxy metabolites of 3-MeO-AAB as determined by two-dimensional thin layer chromatography, and the enzyme responsible for the N-hydroxylation was named 3-MeO-AAB N-hydroxylase . A mutagenicity test using Salmonella typhimurium TA98 bacteria as a tester strain has revealed that N-hydroxy-3-MeO-AAB is a potent direct mutagen but that 4'-hydroxy-3-MeO-AAB is not mutagenic . Although 3-MeO-AAB N-hydroxylase activity in liver microsomes showed no sex difference, the enzyme activity in the kidney was detected from male mice but not from females . However, administration of testosterone to female mice induced the enzyme in the kidney . Castration of male mice depressed the activity of 3-MeO-AAB N-hydroxylase in renal microsomes but it little affected the hepatic activity, and on administration of testosterone to the castrated mice the depressed renal microsomal activity recovered to a normal level . The activity of 3-MeO-AAB hydroxylase and the amount of cytochrome P-450 in renal microsomes showed a close correlation . Both renal and hepatic microsomes required NADPH as a main cofactor to mutagenize 3-MeO-AAB and to yield N-hydroxy-3-MeO-AAB from 3-MeO-AAB, and the enzyme activity was strongly inhibited by 7,8-benzoflavone . When the activities of renal and hepatic 3-MeO-AAB N-hydroxylase were compared on the basis of the amount of cytochrome P-450, the renal type enzyme showed about 8 times greater activity than hepatic type enzyme . These results indicate that the kidney contains an androgen-dependent microsomal 3-MeO-AAB hydroxylase which is different from an isozyme present in the liver and which is a new type of cytochrome P-450 isozyme. Med Lav, 1990 May-Jun, 81(3), 212 - 21 {Identification of genotoxic compounds used in leather processing industry}; Clonfero E et al.; The release of mutagens from 7 carbon black-based leather dyes and from leather samples at various stages of finishing was determined . After vigorous treatment with toluene, 4 commercial dyes yelded mutagenic extracts on Salmonella typhimurium in the presence of microsomal enzymes . Only in one case were the responsible chemicals identified as polycyclic aromatic hydrocarbons . The low bioavailability of mutagens contained in carbon black and their low mutagenic activity suggest that the risk associated with the use of these dyes is probably negligible . Soxhlet extracts with ethanol from finished leather were mutagenic on strain TA98 of Salmonella typhimurium in the absence of S9 mix . Analysis of extracts of leather samples at various intermediate stages of processing showed that mutagenic activity was detectable after the colouring process . The responsible compound was identified as a nitroazo dye (Colour Index: Acid Brown 83), with a mutagenic potential of about 4 revertant/micrograms . Eighteen commercial tannins containing mainly Cr(III) sulphates were assessed for genotoxicity . Most were contaminated with Cr(VI), a known mutagenic and carcinogenic agent, at levels sufficient to induce an increased frequency of SCE (sister chromatid exchanges) in mammalian cells (CHO, chinese hamster ovary) tested in vitro. Mutagenesis, 1990 May, 5(3), 285 - 91 Comparison of Salmonella typhimurium TA102 with Escherichia coli WP2 tester strains; Wilcox P et al.; In 1982, Levin et al . published a paper describing a new Salmonella typhimurium strain, TA102, for detecting mutagenic agents that react preferentially with AT base pairs . This strain has an AT base pair at the critical mutation site within the hisG gene, which is located on a multicopy plasmid, pAQ1; the chromosomal copy of the hisG gene has been deleted . It also has an intact excision repair system, thus facilitating the detection of cross-linking agents, and carries the mutator plasmid, pKM101 . Although TA102 has been shown to be reverted by certain mutagenic agents that are not detected in the usual battery of strains (TA1535, TA1537, TA1538, TA98 and TA100), there has been a general reluctance within the field to include TA102 as one of the standard screening strains . This may in part result from the difficulties which have been experienced in many laboratories in maintaining the strain, and in obtaining reproducible spontaneous and induced revertant counts . At Glaxo we routinely include certain Escherichia coli strains in our microbial test battery, and were aware that some of the genetic features offered by TA102 were already being covered by these strains . For example, E.coli WP2 (pKM101) has an AT base pair at the critical mutation site within the trpE gene, is excision proficient (and thus will detect cross-linking agents) and carries the pKM101 plasmid to enhance error-prone repair . From the published literature it was apparent that a number of the 'TA102 specific' mutagens could be detected in E.coli e.g . neocarzinostatin, UV and 8-MOP plus UV.(ABSTRACT TRUNCATED AT 250 WORDS) Mutagenesis, 1990 May, 5(3), 267 - 74 The comparative responses of Salmonella typhimurium TA1537 and TA97a to a range of reference mutagens and novel compounds; O'Donovan MR; Salmonella typhimurium TA97a was added to the set of indicator strains routinely used for the Ames test in this laboratory (TA1535, TA1537, TA1538, TA98 and TA100) for a trial period during which a total of approximately 40 reference mutagens and novel pharmaceutical compounds were examined . The conclusions from this trial were as follows: (i) there are agents mutagenic for TA1537 which are not detected by TA97a . (ii) except for agents requiring the R factor plasmid, TA97a shows no increased sensitivity to mutagens when compared with TA1537 and (iii) nearly all the limited published database is for the original isolate, TA97, rather than TA97a, and the results obtained here indicate significant differences in response between the two; TA97a remains, therefore, essentially unvalidated. Mutagenesis, 1990 May, 5(3), 263 - 6 Studies on the induction of gene mutations in bacterial and mammalian cells by the ring-opened benzene metabolites trans,trans-muconaldehyde and trans,trans-muconic acid; Glatt H et al.; t,t-Muconaldehyde and t,t-muconic acid have been investigated for the induction of gene mutations in Salmonella typhimurium (reversion of the his- strains TA97, TA98, TA100, TA102, TA104 and TA1535), Escherichia coli (reversion of the trp- strain WP2 uvrA) and Chinese hamster V79 cells (acquisition of resistance toward 6-thioguanine) . t,t-Muconaldehyde proved weakly mutagenic in strain TA104 in the presence and absence of NADPH-fortified postmitochondrial fraction from rat liver homogenate (S9 mix) . In strains TA97, TA100 and TA102, weak positive responses were observed only in the presence of S9 mix . In strains TA98, TA1535 and WP2 uvrA, the result was negative . In V79 cells, the mutation frequency was increased from approximately 7 X 10(-6) to 90 X 10(-6) in cultures exposed to t,t-muconaldehyde at optimal concentration (1.7-3 microM in separate experiments) . The concentration-response curve showed pronounced hyperlinearity, with no mutagenic effect being observed at a third of the optimal concentration . t,t-Muconic acid was greater than 100 times less toxic than t,t-muconaldehyde in both bacteria and mammalian cells, and it did not show any mutagenic effect . These results complete a previous mutagenicity study, carried out on benzene and 13 metabolites . It is concluded that the newly investigated metabolites cannot account for the bacterial mutagenicity of bioactivated benzene and benzene-trans-1,2-dihydrodiol, since these compounds exhibited their strongest response in strain TA1535 . t,t-Muconaldehyde showed similarities in its mutagenicity to p-benzoquinone and hydroquinone . All three compounds showed, at most, weak effects in bacteria, but were strongly mutagenic in V79 cells.(ABSTRACT TRUNCATED AT 250 WORDS) J Antimicrob Chemother, 1990 May, 25(5), 813 - 23 Beta-lactam antibiotics (aztreonam, ampicillin, cefazolin and ceftazidime) in the control and eradication of Salmonella typhimurium in naturally resistant and susceptible mice; Bonina L et al.; This study was undertaken to investigate the efficacy of different beta-lactam antibiotics in the treatment of systemic salmonella infections in the mouse typhoid model . Innately susceptible BALB/c (Itys) and resistant CBA (Ityr) mice were used to investigate the efficacy of one monocyclic (aztreonam) and three bicyclic (ampicillin, cefazolin, ceftazidime) beta-lactam antibiotics in controlling systemic salmonella infections when given for brief or prolonged periods . The present study confirms and amplifies earlier reports on ampicillin therapy, demonstrates marked differences in the efficacy of the different antibiotics and shows that aztreonam is not only very effective but can completely eradicate the salmonellae from the RES when given early in the infection. FEMS Microbiol Immunol, 1990 May, 2(1), 35 - 43 Specific inhibition of phagosome-lysosome fusion in murine macrophages mediated by Salmonella typhimurium infection; Ishibashi Y et al.; Phagosome-lysosome fusion in murine macrophages infected with S . typhimurium LT2 or S . typhi 1079 was investigated . Fusion of phagosome containing S . typhimurium LT2 with lysosome was markedly impaired, whereas S . typhi 1079 did not inhibit phagosome-lysosome fusion in murine macrophages . A similar inhibition of fusion was observed with LPS-deficient mutants of S . typhimurium LT2, suggesting that O-antigens do not contribute to the inhibition of fusion . Phagosome-lysosome fusion in macrophages after ingestion of UV-killed S . typhimurium LT2 was much greater than that of live bacteria . Furthermore, treatment of S . typhimurium LT2 with streptomycin, an inhibitor of bacterial protein synthesis, caused an increase in the extent of phagosome-lysosome fusion . Therefore protein synthesis in live bacteria is probably required for the inhibition of phagosome-lysosome fusion . These results suggest that phagosome-lysosome fusion in murine macrophages is impaired by some product(s) of viable S . typhimurium LT2. Antimicrob Agents Chemother, 1990 May, 34(5), 853 - 7 Antimicrobial susceptibility of Salmonella typhimurium carrying the outer membrane permeability mutation SS-B; Vaara M; The antibiotic susceptibility profile of Salmonella typhimurium SS-B, a mutant susceptible to some antimicrobial agents, was studied in detail . Twenty-eight agents were tested, and eleven of these had MICs significantly lower (32- to greater than 250-fold) for the SS-B strain than for its parent . The drugs were generally hydrophobic or amphiphilic . Polymyxin B nonapeptide, which has a known outer membrane permeabilizing action, further reduced the MIC of several of these agents for the SS-B strain by a factor of approximately 10 to 30 . In most cases, the resulting MICs were lower than the corresponding MICs for the parent strain grown in the presence of polymyxin B nonapeptide . In addition, the hydrophobic fluorescent probe N-phenyl naphthylamine was rapidly embedded in the membranes of the SS-B strain but was poorly embedded in those of the parent strain. Mutat Res, 1990 May, 244(1), 61 - 5 An association between mutagenicity and carcinogenic potency; Rosenkranz HS et al.; A comparison between mutagenic and non-mutagenic rodent carcinogens studied by the U.S . National Toxicology Program revealed that as a group, rat carcinogens mutagenic in Salmonella typhimurium are more potent than their non-mutagenic counterparts. Mutat Res, 1990 May, 244(1), 37 - 42 Mutagenic activity of pyrolysates of cyanocobalamin and some other water-soluble vitamins in the model system with the Salmonella/mammalian microsomes; Demura R et al.; Pyrolysates of cyanocobalamin, thiamine hydrochloride, riboflavin, pyridoxine hydrochloride, and ascorbic acid were tested for mutagenicity in the histidine-requiring mutants Salmonella typhimurium TA98 and TA100 . Each vitamin was sealed in a glass tube and heated at 100-600 degrees C in a muffle furnace . Methanol-chloroform extracts of the pyrolysate of each vitamin tested did not show any mutagenicity in either TA98 or TA100 without rat liver 9000 x g supernatant fraction (S9) added . In the presence of S9, the B-group vitamins (cyanocobalamin, thiamine hydrochloride, riboflavin, and pyridoxine hydrochloride) were all mutagenic in TA98 and TA100, with the highest activity among the vitamins tested found in the pyrolysate of cyanocobalamin . The pyrolysate of 0.25 mumole cyanocobalamin produced 3200 revertants, while the pyrolysates of 0.25 mumole thiamine hydrochloride and riboflavin produced only 910 revertants, and the pyrolysate of pyridoxine hydrochloride did not show any mutagenicity at that amount . The mutagenicity was generally more active to TA98 than to TA100, indicating that frameshift-type mutagens were contained in the pyrolysates . The pyrolysate of ascorbic acid did not show any mutagenic activity in either TA98 or TA100 under the present experimental conditions. J Bacteriol, 1990 May, 172(5), 2485 - 90 Constitutive expression of the phoP regulon attenuates Salmonella virulence and survival within macrophages; Miller SI et al.; The phoP genetic locus is a two-component regulatory system (phoP-phoQ) that controls the expression of genes essential for Salmonella typhimurium virulence and survival within macrophages . Strains with a phoP constitutive mutation (phenotype PhoPC) showed up to 10-fold greater expression of phoP-activated genes (pag loci) than did strains with a wild-type phoP locus (phenotype PhoP+) . While the phoP constitutive mutation resulted in increased expression of pag loci, it also dramatically reduced the expression of other protein species . Comparison of the protein content of PhoP+ and PhoPC strains by two-dimensional protein gel electrophoresis demonstrated that at least 40 separate protein species were changed in expression as a result of this mutation . The PhoPC S . typhimurium were found to be attenuated for virulence and survival within macrophages . This finding suggests that a balanced PhoP-PhoQ regulatory response, which allows expression of phoP-repressed as well as -activated genes, is required for full virulence of S . typhimurium . We have further shown that small numbers of PhoPC bacteria can be used as a live attenuated vaccine to protect against mouse typhoid . As few as 15 PhoPC bacteria protected mice against challenge with 10(5) 50% lethal doses of wild-type organisms, suggesting that important protective antigens are regulated by the PhoP-PhoQ virulence regulon. Infect Immun, 1990 May, 58(5), 1323 - 6 Oral vaccination of mice against tetanus by use of a live attenuated Salmonella carrier; Fairweather NF et al.; A Salmonella typhimurium aroA mutant has been used as a live carrier to immunize mice against tetanus . Plasmid pTETtac4, which expresses a 50-kilodalton fragment of tetanus toxin (fragment C) under the control of the tac promoter, was introduced into SL3261 aroA . When used as a live vaccine and administered orally or intravenously, this strain was able to induce protective immunity in mice against a lethal tetanus toxin challenge . When plasmid pTETtac2, which contains the lacI gene, was used, no immunity was obtained, indicating that the expression of fragment C was repressed in vivo . We believe that this is the first example of a successful oral vaccination that uses an attenuated bacterial carrier to deliver a protective antigen derived from tetanus toxin. J Gen Microbiol, 1990 May, 136 ( Pt 5), 887 - 96 Cobalamin-dependent 1,2-propanediol utilization by Salmonella typhimurium; Jeter RM; The enteric bacterium Salmonella typhimurium utilizes 1,2-propanediol as a sole carbon and energy source during aerobic growth, but only when the cells are also provided with cobalamin as a nutritional supplement . This metabolism is mediated by the cobalamin-dependent propanediol dehydratase enzyme pathway . Thirty-three insertion mutants were isolated that lacked the ability to utilize propanediol, but retained the ability to degrade propionate . This phenotype is consistent with specific blocks in one or more steps of the propanediol dehydratase pathway . Enzyme assays confirmed that propanediol dehydratase activity was absent in some of the mutants . Thus, the affected genes were designated pdu (for defects in propanediol utilization) . Seventeen mutants carried pdu::lac operon fusions, and these fusions were induced by propanediol in the culture medium . All of the pdu mutations were located in a single region (41 map units) on the S . typhimurium chromosome between the his (histidine biosynthesis) and branch I cob (cobalamin biosynthesis) operons . They were shown to be P22-cotransducible with a branch I cob marker at a mean frequency of 12% . Mutants that carried deletions of the genetic material between his and cob also failed to utilize propanediol as a sole carbon source . Based upon the formation of duplications and deletions between different pairs of his::MudA and pdu::MudA insertions, the pdu genes were transcribed in a clockwise direction relative to the S . typhimurium genetic map. Mutat Res, 1990 May, 230(1), 55 - 60 The effect of plasmid pKM101 on umuDC gene function enhancing precise excision of transposons; Andreeva IV et al.; Mutation in the thr gene with the highest UV-induced reversion frequency has been chosen from a number of mutations arisen from insertion of transposon Tn10 into the umuDC- Salmonella typhimurium . This mutation has been transferred by transduction into the Salmonella strain carrying E . coli umuDC+ genes . umuDC- and umuDC+ Salmonella strains, bearing the same insertion mutation, were used to study the effect of umuDC genes and of plasmid pKM101 on spontaneous and UV-induced precise excision of Tn10 . This process, like point mutagenesis, is shown to be umuDC-stimulated . Plasmid pKM101 eliminates the effect of umuDC+ genes on UV-induced Tn10 precise excision, in contrast to its effect on point mutagenesis, and does not enhance spontaneous precise excision of Tn10. Zh Mikrobiol Epidemiol Immunobiol, 1990 May, (5), 38 - 42 {Trends in the development of the epidemic process in salmonellosis caused by Salmonella typhimurium and Salmonella enteritidis}; Sergevnin VI et al.; The dynamics and structure of the epidemic process of Salmonella infections among the population of Perm in 1983-1988 was studied and the results of evaluation of antibiotic resistance of the dominating Salmonella species analyzed . The study revealed that a decrease in salmonellosis morbidity caused by S . typhimurium was associated with a limited circulation of anthroponotic (antibiotic-resistant) variants of Salmonellae and a relative increase in the proportion of zoonotic (antibiotic-sensitive) strains . At the period of elevated morbidity this Salmonella infection affected mainly young children in cold months, whereas in recent years seasonal morbidity rises shifted to spring-summer and summer-autumn months, affecting older age groups of the population . The study also revealed that a rise in salmonellosis morbidity caused by S . enteritidis was due to increased circulation of zoonotic variants of Salmonellae . Changes in the epidemiological situation necessitate correction of the system of epidemiological surveillance on Salmonella infections with the emphasis on sanitation measures in stock-breeding farms with unfavorable epidemiological situation. Chem Res Toxicol, 1990 May-Jun, 3(3), 195 - 8 Reevaluation of the effect of ellagic acid on N-methyl-N-nitrosourea DNA alkylation and mutagenicity; Lord HL et al.; N-Methyl-N-nitrosourea (MNU) is a reactive, mutagenic methylating agent . MNU methylates DNA at various sites, including guanine N7, guanine O6, and adenine N3 . Dixit and Gold {(1986) Proc . Natl . Acad . Sci . U.S.A . 83, 8039-8043} reported that ellagic acid, a phenolic natural product, inhibited the mutagenicity of MNU in Salmonella typhimurium strain TA 100, inhibited salmon sperm DNA alkylation by {3H}MNU, and also greatly reduced the ratio of guanine O6 to guanine N7 alkylation . We have examined the MNU-induced alkylation of calf thymus DNA and evaluated the effect of ellagic acid on this binding . Ellagic acid had only a slight effect on total alkylation and did not alter the ratio of methylation at guanine-O6 and -N7 positions . In further experiments, ellagic acid did not significantly inhibit MNU mutagenicity . These findings do not support the potential use of ellagic acid as an inhibitor of biological damage induced by nitrosoureas. J Bacteriol, 1990 May, 172(5), 2209 - 16 Recombination of Salmonella phase 1 flagellin genes generates new serovars; Smith NH et al.; To determine the evolutionary mechanisms generating serotypic diversity in Salmonella strains, we sequenced the central, antigen-determining part of the phase 1 flagellin gene (fliC) in strains of several serovars for which estimates of chromosomal genomic relatedness had been obtained by multilocus enzyme electrophoresis . The nucleotide sequence of this region was identical in several chromosomally divergent strains of Salmonella heidelberg (phase 1 antigen r) but differed by 19% from the corresponding and similarly invariant sequence in strains of the closely related serovar Salmonella typhimurium (phase 1 antigen i) . Mutational drift of the sequence present in the common ancestor is unlikely to have generated the difference between the phase 1 flagellins of these two serovars, which we attribute instead to a recombination event . This interpretation is supported by evidence that Salmonella strains of very diverse chromosomal backgrounds but similar phase 1 antigens may have closely similar nucleotide sequences for this highly polymorphic region . We suggest that lateral transfer and recombination of phase 1 flagellin genes is a major evolutionary mechanism generating new Salmonella serovars. J Pediatr Gastroenterol Nutr, 1990 May, 10(4), 530 - 5 Effect of vitamin A deficiency on the adherence of fimbriated and nonfimbriated Salmonella typhimurium to isolated small intestinal enterocytes; Gabriel EP et al.; In vitamin A-deficient children, increased rates of bacterial infections in the intestine have been observed . The adherence of bacteria is a prerequisite for invasion . Thus, the effect of vitamin A deficiency on the adherence of fimbriated and nonfimbriated Salmonella typhimurium to isolated small intestinal enterocytes was studied . Male weanling rats matched by weight were divided into three groups: one group was fed a vitamin A-free diet for 8-12 weeks; another was given the same diet supplemented with retinol acetate; a third group matched for age served as controls . The vitamin A-deficient group showed a significantly lower growth rate and lower serum retinol levels than either the retinol acetate-supplemented or control groups . In all the groups, S . typhimurium possessing mannose-sensitive fimbriae adhered to enterocytes in significantly larger numbers than the nonfimbriated strains . The number of fimbriated S . typhimurium bound to enterocytes from the proximal small intestine was significantly higher in the vitamin A-deficient rats than in the pair-fed vitamin A-supplemented group (19.3 +/- 14.9 versus 7.8 +/- 5.0; p less than 0.05) or the control group (19.3 +/- 14.9 versus 8.7 +/- 3.5, p = 0.01) . The specific activities of the enterocytes lactase, sucrase, and maltase and the protein content in the vitamin A-deficient rats were similar to those in the controls . These results demonstrate that vitamin A deficiency in rats is associated with the increased ability of S . typhimurium to adhere to proximal small intestinal enterocytes . However, the possible changes in the membrane of the enterocyte do not include decreases in brush border disaccharidases or protein content. J Bacteriol, 1990 May, 172(5), 2259 - 66 Regulation of the Salmonella typhimurium aroF gene in Escherichia coli; Muday GK et al.; The Salmonella typhimurium aroF gene, encoding the tyrosine-sensitive 3-deoxy-D-arabino-heptulosonate 7-phosphate (DAHP) synthase, was localized to a chromosomal PstI fragment by Southern blotting with an Escherichia coli aroF probe . This fragment was cloned by screening a plasmid library for complementation of an E . coli aroF mutant . The nucleotide sequence of S . typhimurium aroF was determined and compared with its E . coli homolog . The nucleotide sequences are 85.1% identical, and the corresponding amino acid sequences are 96.1% identical . The E . coli genes encoding the three DAHP synthase isoenzymes are evolutionarily more distant from one another than are the homologous aroF genes of E . coli and S . typhimurium . The S . typhimurium aroF regulatory region contains three imperfect palindromes, two upstream of the promoter and one overlapping the promoter, that are nearly identical to operators aroFo1, aroFo2, and TyrR box 1 of E . coli . The aroFo1 and aroFo2 sequences of the two organisms are each separated by three turns of the DNA helix with no sequence similarity . The 5' ends of the aroF transcripts for both organisms contain untranslated regions with potential stem-loop structures . Translational fusions of the aroF regulatory regions to lacZ were constructed and then introduced in single copy into the E . coli chromosome . beta-Galactosidase assays for tyrR-mediated regulation of aroF-lacZ expression revealed that the E . coli TyrR repressor apparently recognizes the operators of both organisms with about equal efficiency. Tokai J Exp Clin Med, 1990 May, 15(2-3), 111 - 21 Ecological mechanism of protection of intestinal bacterial flora against Salmonella typhimurium infection; Ozawa A et al.; Our results indicate that the responsiveness of the phagocytic and intracellular killing process of peripheral blood granulocytes and peritoneal phagocytic cells in infected germfree mice is due primarily to the OCl- (hypochloride ion) with myeloperoxidase involvement, while the response in infected conventional mice is brought about mainly by the O2- (superoxide anion) . These facts are believed to be invaluable footholds in elucidating the quantitative and qualitative differences in phagocytic cell response depending upon the presence or absence of intestinal flora. Nucleic Acids Res, 1990 Apr 25, 18(8), 2079 - 86 The signal for the termination of protein synthesis in procaryotes; Brown CM et al.; The sequences around the stop codons of 862 Escherichia coli genes have been analysed to identify any additional features which contribute to the signal for the termination of protein synthesis . Highly significant deviations from the expected nucleotide distribution were observed, both before and after the stop codon . Immediately prior to UAA stop codons in E . coli there is a preference for codons of the form NAR (any base, adenine, purine), and in particular those that code for glutamine or the basic amino acids . In contrast, codons for threonine or branched nonpolar amino acids were under-represented . Uridine was over-represented in the nucleotide position immediately following all three stop codons, whereas adenine and cytosine were under-represented . This pattern is accentuated in highly expressed genes, but is not as marked in either lowly expressed genes or those that terminate in UAG, the codon specifically recognised by polypeptide chain release factor-1 . These observations suggest that for the efficient termination of protein synthesis in E . coli, the 'stop signal' may be a tetranucleotide, rather than simply a tri-nucleotide codon, and that polypeptide chain release factor-2 recognises this extended signal . The sequence following stop codons was analysed in genes from several other procaryotes and bacteriophages . Salmonella typhimurium, Bacillus subtilis, bacteriophages and the methanogenic archaebacteria showed a similar bias to E . coli. Eur J Biochem, 1990 Apr 20, 189(1), 119 - 24 Translational regulation of M13 gene II protein by its cognate single-stranded DNA binding protein; Zaman GJ et al.; To unravel the mechanism by which the single-stranded DNA binding protein encoded by gene V of the filamentous phage M13 regulates the synthesis of its cognate DNA replication protein encoded by gene II, an in vivo test system has been developed . The system consists of two recombinant plasmids with compatible replication origins . One plasmid contains M13 gene V under the control of the inducible araB promoter of Salmonella typhimurium . The other plasmid contains a fusion gene, whose expression is dependent upon the M13 gene-II-promoter and which consists of the 5' end of M13 gene II and the 5'-truncated beta-galactosidase gene of Escherichia coli . Induction of the synthesis of wild-type gene V protein by arabinose resulted in a specific reduction of both the beta-galactosidase activity and the amount of fusion protein produced . These specific inhibitory effects were not observed when the synthesis of the fusion protein was studied in the presence of an amber mutant of gene V . Comparison of the relative concentrations of the fusion protein mRNAs, as present in arabinose-induced and noninduced cells, provided solid and direct evidence for the conclusions made in earlier publications, that gene V protein exerts its regulatory effect at the level of translation . Since the transcript of the fusion gene only contains the first 74 nucleotides of gene II mRNA, it is furthermore concluded that these nucleotides are already sufficient for gene V protein to exert its regulatory effect. Cancer Lett, 1990 Apr 20, 50(2), 149 - 56 Inhibition of liver microsome-mediated mutagenesis, metabolism and DNA-binding of benzo{a}pyrene and benzo{a}pyrene 7,8-dihydrodiol in the rat following glucose administration; Vance RE et al.; Aroclor 1254-induced rat liver microsomes prepared from control and glucose-treated rats (30% glucose in drinking water 48 h prior to sacrifice) were used in studies of benzo{a}pyrene (BaP) and BaP 7,8-dihydrodiol (BaP 7,8-DHD)-induced mutagenesis in Salmonella typhimurium TA100 . Microsome-dependent metabolism and metabolite binding of BaP and BaP 7,8-DHD to calf thymus DNA was also investigated . BaP-induced mutagenesis in TA100 was inhibited 27% and BaP 7,8-DHD-induced mutagenesis was inhibited 55% by microsomes from glucose-treated rats . {3H}BaP and {3H}BaP 7,8-DHD metabolite binding to DNA was inhibited 17% and 20%, respectively . High performance liquid chromatographic (hplc) analysis of enzyme-hydrolyzed DNA yielded 7R and 7S-diol epoxide-1 deoxyguanosine (BPDE-1:dG) adducts and BPDE-2:dG adducts of {3H}BaP and {3H}BaP 7,8-DHD . These adducts were inhibited 38% and 50%, respectively, by microsomes from glucose-treated rats . Hplc analysis of organosoluble metabolites of {3H}BaP and {3H}BaP 7,8-DHD showed an inhibition of metabolism of 28% and 50%, respectively, by microsomes from glucose-treated rats . The inhibition of metabolism correlated with the effect of glucose treatment on inhibition of BaP and BaP 7,8-DHD-induced mutagenesis and adduct formation . These results suggest that the mechanism by which glucose produces its effects on mutagenesis, DNA-binding and adduct formation is by an inhibition of microsome-mediated metabolism of BaP and BaP 7,8-DHD. J Immunol, 1990 Apr 15, 144(8), 3143 - 51 The primary effect of the Ity locus is on the rate of growth of Salmonella typhimurium that are relatively protected from killing; Benjamin WH Jr et al.; The Ity locus affects the net increase in numbers of Salmonella typhimurium in the liver and spleen of infected mice . There has been controversy, however, about whether the effects of this locus are due to differential killing of S . typhimurium or differential growth rates of S . typhimurium in mice . Our studies using S . typhimurium aroA mutants, which do not grow in vivo, demonstrate that growth of the infecting salmonella is necessary for the observation of the Ity phenotype . To examine the effects of the Ity locus on the growth and killing of fully virulent salmonella, we infected Ity-congenic mice i.v . with stationary phase S . typhimurium containing a single copy of the plasmid pHSG422 . This plasmid exhibits defective replication at body temperature and is diluted out during salmonella growth in vivo . Thus, the frequency of plasmid-containing salmonella recovered from mice provides a measure of salmonella cell divisions in vivo . Inasmuch as the numbers of plasmid-containing salmonella are only slightly affected by bacterial division, any decline in the numbers of plasmid-containing salmonella is an unbiased measure of killing . By infecting mice with these plasmid-containing salmonella we observed that: 1) during the first four h post infection (during blood clearance of injected salmonella) there is about 3-fold more killing of salmonella in Ityr mice than in Itys mice; 2) from 4 to 44 h postinfection (after blood clearance is completed) there is little if any additional killing in either Itys or Ityr mice; and 3) during the first 48 h postinfection there is about 18-fold more growth of salmonella in Itys mice than in Ityr mice . Thus, the major effect of the Ity locus on resistance to salmonella, is the regulation of growth within a "safe" (relatively nonbactericidal) site in the liver and spleen. Science, 1990 Apr 13, 248(4952), 189 - 94 Transcriptional regulator of oxidative stress-inducible genes: direct activation by oxidation; Storz G et al.; The oxyR gene positively regulates genes induced by oxidative stress in Salmonella typhimurium and Escherichia coli . Purification of the OxyR protein showed that oxidized but not reduced OxyR activates transcription of oxidative stress-inducible genes in vitro . Conversion between the two forms of OxyR is rapid and reversible . Both the oxidized and the reduced forms of the OxyR protein are capable of binding to three diverse sequences upstream of OxyR-regulated promoters, but the interactions of the two forms of OxyR with the promoter regions are different . The results suggest that direct oxidation of the OxyR protein brings about a conformational change by which OxyR transduces an oxidative stress signal to RNA polymerase. J Biol Chem, 1990 Apr 5, 265(10), 5487 - 93 Chemical modification of Salmonella typhimurium phosphoribosylpyrophosphate synthetase with 5'-(p-fluorosulfonylbenzoyl)adenosine . Identification of an active site histidine; Harlow KW et al.; Liquid chromatographic procedures have been developed for rapidly locating the site of reaction of chemical modification reagents with Salmonella typhimurium 5-phosphoribosyl-alpha-1-pyrophosphate (PRPP) synthetase . The enzyme was reacted with the active site-directed reagent 5'-(p-fluorosulfonylbenzoyl)adenosine (FSBA) . FSBA bound to the enzyme with an apparent KD of 1.7 +/- 0.4 mM . The enzyme was inactivated during the reaction, and a limiting stoichiometry of 1.2 mol of FSBA/mol of enzyme subunit corresponded to complete inactivation . Inclusion of ATP in the reaction protected the enzyme from inactivation and incorporation of the reagent . Inclusion of ribose 5-phosphate increased the rate of reaction of PRPP synthetase with FSBA . Amino acid analyses of acid hydrolysates of modified enzyme failed to detect any known FSBA-amino acid adducts . Tryptic digestion of 5'-(p-fluorosulfonylbenzoyl)-{3H}adenosine-modified enzyme at pH 7.0 yielded a single radioactive peptide . The peptide, TR-1, was subjected to combined V8 and Asp-N protease digestion, and a single radioactive peptide was isolated . This radioactive peptide yielded the sequence Asp-Leu-His-Ala-Glu, which corresponded to amino acid residues 128-132 in S . typhimurium PRPP synthetase . No radioactivity was associated with any of the phenylthiohydantoin-amino acid fractions, all of which were recovered in good yield . A majority of the radioactivity was found in the waste effluent (64%) and on the glass fiber filter loaded into the sequenator (23%) . The lability of the modification and the sequence of this peptide indicate His130 as the site of reaction with FSBA. Mol Microbiol, 1990 Apr, 4(4), 633 - 44 The ami locus of the gram-positive bacterium Streptococcus pneumoniae is similar to binding protein-dependent transport operons of gram-negative bacteria; Alloing G et al.; The complete nucleotide sequence of the ami locus of Streptococcus pneumoniae revealed the presence of six open reading frames, amiABCDEF . The predicted Ami proteins are probably involved in a transport system . The AmiA, C, D, E, and F proteins exhibit homology with components of the oligopeptide permeases (opp) of Salmonella typhimurium and Escherichia coli . Intriguingly, the AmiB protein is homologous to ArsC, a cytosolic modifier subunit of the anion pump encoded by the arsenical resistance operon of the R-factor R773 from E . coli . Data are presented which indicate that Ami is indeed a transport system. Mol Gen Genet, 1990 Apr, 221(2), 139 - 47 Gene fliA encodes an alternative sigma factor specific for flagellar operons in Salmonella typhimurium; Ohnishi K et al.; Through genetic studies, the fliA gene product has been shown to regulate positively gene expression in late operons of the flagellar regulon in Salmonella typhimurium . In the present study, the fliA gene was cloned and sequenced . The fliA coding region consisted of 717 nucleotides beginning with the GTG initiation codon and the conserved sequence specific to promoters for flagellar operons was found to exist upstream of the coding region . The fliA gene product deduced from the nucleotide sequence was a protein with 239 amino acid residues and the calculated molecular mass was 27,470 dalton . The deduced amino acid sequence was homologous with that of sigma 28, a flagellar specific sigma factor of Bacillus subtilis . The fliA gene product was identified as a protein of molecular mass 29 kDa in the in vitro transcription-translation system, while three proteins of 29 kDa, 31 kDa and 32 kDa were found in the products programmed by the fliA gene in minicells and in maxicells . The 29 kDa FliA protein was purified from the FliA overproducing strain which carried the ptac-fliA fusion . This protein activated the in vitro synthesis of flagellin, the fliC gene product . RNA polymerase containing the purified FliA protein was shown to transcribe the fliC gene . These results indicate that FliA protein functions as an alternative sigma factor specific for S . typhimurium flagellar operons. Avian Dis, 1990 Apr-Jun, 34(2), 463 - 5 Salmonella typhimurium penetration through the eggshell of hatching eggs; Padron M; This study was undertaken to demonstrate penetration of Salmonella typhimurium through the eggshell of newly laid broiler hatching eggs . Eggs were challenged either by lightly spraying the bacteria over the blunt end of the egg or by contact with contaminated dry nest litter . Exposure time for both groups was 10 minutes; afterward, all eggs were disinfected and incubated 19 days under normal conditions . Chorioallantoic membranes and yolk sacs were cultured in brain-heart infusion broth on day 19 to demonstrate penetration . Isolation of the bacteria from chorioallantoic membranes and yolk sacs, respectively, were as follows: sprayed group: 100% and 83%; contact group: 59% and 29% . These results showed that although water enhanced S . typhimurium penetration, its presence on the eggshell is not essential for penetration to occur. Avian Dis, 1990 Apr-Jun, 34(2), 389 - 92 Reduction of Salmonella typhimurium concentration in broiler chickens by milk or whey; DeLoach JR et al.; Whey (5%) in the feed of chicks for the first 10 days of life reduced the mean log10 number of viable S . typhimurium from 5.68 in control chickens to 3.38 in whey-fed chickens . Lactose in drinking water or reconstituted dry milk (5% wt: vol) in drinking water reduced the mean log10 number of S . typhimurium to 2.60 and 2.11, respectively . Milk (5% wt: wt) in feed was not effective in reducing S . typhimurium colonization . The lack of effect of milk in the feed is believed to be because not enough lactose was provided at the 5% (wt: wt) concentration . Lactose in whey or nonfat dried milk offers alternatives to the use of pure lactose in preventing or lowering S . typhimurium numbers in young broiler chickens. Microbiologica, 1990 Apr, 13(2), 115 - 9 Microbial mutagenicity screening of natural flavouring substances; Crebelli R et al.; Sixty-five commercial samples of natural flavouring substances were screened for mutagenicity in the Salmonella typhimurium strains TA98 and TA100 . The results obtained demonstrated a significant mutagenic activity in onion and garlic extracts, both in assays with and without exogenous metabolic activation . The response pattern obtained in tester strains with different genetic backgrounds suggests the involvement of mutagenic flavone(s) in the genotoxic effects observed. J Antimicrob Chemother, 1990 Apr, 25(4), 629 - 34 Treatment of experimental Salmonella typhimurium infection in mice with lomefloxacin; Butler T et al.; To evaluate the difluorinated quinolone lomefloxacin in murine typhoid, mice were inoculated intraperitoneally with the LT-2 strain of Salmonella typhimurium and treated with graded doses of the drug given once daily by an orogastric needle . Treatment with lomefloxacin for seven days reduced mortality with a 50% effective dose of 2.5-7.8 mg/kg/day . When given once daily for three days, doses greater than or equal to 5 mg lomefloxacin/kg/day caused significant reductions in splenic counts of S . typhimurium and prevented the inflammatory response to infection in the spleen. Appl Environ Microbiol, 1990 Apr, 56(4), 1038 - 45 Low-pH-induced effects on patterns of protein synthesis and on internal pH in Escherichia coli and Salmonella typhimurium; Hickey EW et al.; Escherichia coli and Salmonella typhimurium were grown in a supplemented minimal medium (SMM) at a pH of 7.0 or 5.0 or were shifted from pH 7.0 to 5.0 . Two-dimensional gel electrophoretic analysis of proteins labeled with H2(35)SO4 for 20 min during the shift showed that in E . coli, 13 polypeptides were elevated 1.5- to 4-fold, whereas in S . typhimurium, 19 polypeptides were increased 2- to 14-fold over the pH 7.0 control . Upon long-term growth at pH 5.0, almost double the number of polypeptides were elevated twofold or more in S . typhimurium compared with E . coli . In E . coli, there was no apparent induction of heat shock proteins upon growth at pH 5.0 in SMM . However, growth of E . coli in a complex broth to pH 5.0, or subsequent growth of fresh E . coli cells in the filtrate from this culture, showed that a subset of five polypeptides is uniquely induced by low pH . Two of these polypeptides, D60.5, the inducible lysyl-tRNA synthetase, and C62.5, are known heat shock proteins . Measurements of the internal pH (pHi) and growth rates of both organisms were made during growth in SMM at pH 7.0, pH 5.0, and upon the pH shift . The data show that the pHi of E . coli decreases more severely than that of S . typhimurium at an external pH of 5.0; the growth rate of E . coli is about one-half that of S . typhimurium at this pH, whereas the two organisms have the same growth rate at pH 7.0 . The two-dimensional gel, growth, and pHi experiments collectively suggest that, at least in SMM, S . typhimurium is more adaptive to low-pH stress than is E . coli. Scand J Immunol, 1990 Apr, 31(4), 453 - 60 In vivo and in vitro antibacterial activity of conglutinin, a mammalian plasma lectin; Friis-Christiansen P et al.; Conglutinin is a mammalian C-type lectin which agglutinates iC3b-coated erythrocytes . Ingram {13} found that euglobulin from bovine serum may confer partial protection against experimental infections in mice . We now present evidence that the protective activity in euglobulin against infections of BALB/c mice with Salmonella typhimurium is mediated by conglutinin . Conglutinin also demonstrated antibacterial activity against E . coli and S . typhimurium in vitro . The expression of this activity required the presence of heat-labile serum factors and peritoneal exudate or spleen cells, but not antibodies to the bacteria . Antibacterial activity was also demonstrated when the bacteria were pretreated with serum at 37 degrees C before incubation with conglutinin and cells . The activity of conglutinin was not observed when factor I-deficient or EDTA-treated serum was used instead of normal serum . The active peritoneal exudate or spleen cells showed adherence to plastic. Mutat Res, 1990 Apr, 240(4), 295 - 306 Genetic toxicity of the benzene metabolite trans, trans-muconaldehyde in mammalian and bacterial cells; Witz G et al.; Previous studies in our laboratory identified trans,trans-muconaldehyde (MUC), a six-carbon diene dialdehyde, as a microsomal metabolite of benzene . This ring-opened metabolite of benzene was also shown to be hematotoxic in mice in a manner similar to benzene . To further explore the role of MUC in relation to benzene toxicity, a number of test systems were utilized to determine its genotoxic potential . In B6C3F1 mice, MUC induced a highly significant increase in sister-chromatid exchange (SCE), the lowest effective dose being 3 mg/kg, but failed to induce any micronuclei (MN) . In Chinese hamster ovary (CHO) cells, MUC at concentrations up to 0.8 micrograms/ml was negative in the hypoxanthine-guanine phosphoribosyl transferase (HGPRT) assay . Dose-related increases in the percentage of cells with MN were observed in CHO cells treated with 0.4-0.8 micrograms/ml MUC . MUC did not-cause unscheduled DNA synthesis in rat primary hepatocytes . Treatment of Salmonella typhimurium TA97 with MUC induced a low level of mutations at concentrations ranging from 10 to 70 micrograms/ml with or without S9 activation . MUC was inactive in strains TA1535, TA100, TA1538 and TA98 . In CHO cells and rat primary hepatocytes, MUC was cytotoxic at 0.4 and 4.0 micrograms/ml, respectively . Concentrations of 100 micrograms/plate MUC were toxic for bacterial cells . The present findings indicate that MUC is nonmutagenic or minimally mutagenic in bacterial and mammalian in vitro systems . In mammalian cells, MUC is highly cytotoxic and genotoxic. Mutat Res, 1990 Apr, 240(4), 267 - 79 Mutagenicity of isoquinoline alkaloids, especially of the aporphine type; Nozaka T et al.; The mutagenicity of 44 isoquinoline alkaloids was tested in Salmonella typhimurium TA100 and TA98 in the presence or absence of S9 mix . The alkaloids tested included compounds from the isoquinoline, benzylisoquinoline, bisbenzylisoquinoline, monoterpene isoquinoline, berberine, morphinane, hasubanan, benzo{c}phenanthridine and aporphine groups . Among the alkaloids tested, liriodenine was the most potent mutagen for TA100 and roemerine was the most potent for TA98 . A clear structure-mutagenicity relationship was observed in a series of aporphine alkaloids (aporphine, dehydroaporphine, 7-oxoaporphine and 4,5-dioxoaporphine), and 10,11-non-substituted aporphines were suggested to exert their mutagenicity through metabolic activation of the 10,11 positions, possibly as the 10,11-epoxides. Mutat Res, 1990 Apr, 240(4), 259 - 66 Occurrence of 2-amino-3-methylimidazo{4,5-f}quinoline (IQ), 2-amino-6-methyldipyrido{1,2-a:3',2'-d}imidazole (Glu-P-1) and other heterocyclic amine mutagens in oil of charred egg yolk (ranyu); Kato T et al.; Mutagenicity of oil of charred egg yolk (called ranyu in Japanese), which is commercially available and consumed as a health food in Japan, was tested on Salmonella typhimurium strains TA98 and TA100 with and without metabolic activation . Both strains showed a high response to the oil, and the number of His+ revertant colonies with strain TA98 was 15,000-20,000 for 1 g equivalent amount of oil . The mutagens were purified by acid extraction, chloroform extraction after alkalization, dialysis, adsorption to blue cotton, passing through a Sephadex LH-20 column and several stages of high-pressure liquid chromatography with reverse-phase columns . At least 7 heterocyclic amine mutagens were detected . Two of them were suggested to be 2-amino-3-methylimidazo{4,5-f}quinoline (IQ) and 2-amino-6-methyldipyrido {1,2-a:3',2'-d}imidazole (Glu-P-1) . One was suggested to be 2-amino-3,4-dimethylimidazo{4,5-f}quinoline (MeIQ) . The others were not identified but distinguishable from 12 known heterocyclic amine mutagens . The estimated minimum contents of IQ and Glu-P-1 were 1.1 ng/g and 4.8 ng/g, respectively. Am J Vet Res, 1990 Apr, 51(4), 619 - 24 Peroxidase-antiperoxidase and immunogold labeling of Salmonella typhimurium and Salmonella choleraesuis var kunzendorf in tissues of experimentally infected swine; Pospischil A et al.; Peroxidase-antiperoxidase immunoenzymatic labeling and immunogold labeling techniques were evaluated for microscopic detection and location of Salmonella organisms in tissues of experimentally infected swine . Salmonella typhimurium and Salmonella choleraesuis var kunzendorf were labeled specifically by the peroxidase-antiperoxidase technique in paraffin-embedded tissues of infected swine for conventional light microscopy and by postembedding immunogold labeling on ultrathin sections for electron microscopy . Salmonella typhimurium had a low tendency to invade the enteric mucosa and did not reveal any predilection for a specific intestinal location . Salmonella choleraesuis var kunzendorf, however, was located preferentially in colon and on the luminal surface of ileal M cells of Peyer patches and had a tendency to invade the enteric mucosa there. Mutat Res, 1990 Apr, 243(4), 303 - 8 Influence of S9 mix on the expression of mutants in the L-arabinose resistance test of Salmonella typhimurium; Roldan-Arjona T et al.; S9 mix produces an effect similar to that of D-glucose in the L-arabinose resistance test of Salmonella typhimurium, releasing the growth inhibition exerted by L-arabinose . Two elements are responsible for this effect: the glucose-6-phosphate present in the cofactors of the S9 mix and the S9 fraction itself . UV light was used as a mutagen to compare the efficiency of S9 mix and D-glucose in allowing phenotypic expression of mutants in selective plates with L-arabinose; 0.5 ml of S9 mix per plate showed and efficacy similar to that of 0.5 mg of D-glucose per plate . To verify that the S9 mix is equivalent to D-glucose traces in selective plates with respect to the number of induced mutants in compounds requiring metabolic activation, we utilized 2 direct-acting nitrofurans . Our conclusion is that activation of agents could be erroneously attributed to the S9 mix, when plates with 0.5 mg of D-glucose are compared to plates with 0.5 ml of S9 mix plus 0.5 mg of D-glucose . Our results suggest that D-glucose traces be omitted in experiments requiring the presence of the S9 mixture. Mutat Res, 1990 Apr, 243(4), 249 - 53 5-Formyldeoxyuridine: a new type of DNA damage induced by ionizing radiation and its mutagenicity to salmonella strain TA102; Kasai H et al.; An aqueous solution of calf thymus DNA was irradiated by 60Co gamma-rays and modified nucleosides produced in DNA were analyzed by high-pressure liquid chromatography coupled with a photodiode array UV detector . A new product with UV absorption maxima at 230 nm and 280 nm was observed . The structure of this compound was proposed to be 5-formyldeoxyuridine (f5dU) based on the mass spectrum of its trimethylsilyl derivative (M+, m/z472) and the structure was confirmed by chemical synthesis . The yield of f5dU (2.4/10(4) dT/krad) in DNA was of roughly the same order as that of 8-hydroxydeoxyguanosine and 5-hydroxymethyldeoxyuridine . Free f5dU was mutagenic to Salmonella typhimurium strain TA102: therefore f5dU incorporated into DNA may induce mutations. Epidemiol Infect, 1990 Apr, 104(2), 243 - 51 Plasmid profile typing can be used to subdivide phage-type 49 of Salmonella typhimurium in outbreak investigations; Threlfall EJ et al.; Plasmid profile typing has been used to subdivide phage-type 49 of Salmonella typhimurium, the most common phage type in humans in England and Wales since 1985 . Twenty profile patterns have been identified in 350 strains examined . Four profile patterns have been identified in 143 isolates from patients infected in 33 epidemiologically unrelated incidents and two patterns have predominated, ST49:62 and ST49:62, 1 . These patterns were also common amongst S . typhimurium phage-type 49 isolated from cattle and poultry; however ST49:62 was more common in bovines whereas ST49:62, 1 predominated in poultry . S . typhimurium phage-type 49 with a different profile pattern, ST49:62, 3, was responsible for a large outbreak in London in 1988 which was traced to mayonnaise made from eggs supplied by one producer . Plasmid profile typing can now be regarded as a method of supplementing phage typing in investigating outbreaks caused by this organism. Infect Immun, 1990 Apr, 58(4), 935 - 7 Induction of hypersensitivity to endotoxin and tumor necrosis factor by sublethal infection with Salmonella typhimurium; Matsuura M et al.; The effect of sublethal infection with Salmonella typhimurium on the sensitivity of mice to the lethal activity of lipopolysaccharide (LPS) was studied in C3H/TifF mice . These mice are more resistant to S . typhimurium infection and survive inocula that are lethal for most other strains of mice . Infection of C3H/TifF mice with 2 x 10(4) CFU of S . typhimurium was without lethal effect . However, administration of LPS at different times after infection revealed that the sensitivity of the animals to the lethal activity of LPS increased exponentially, reaching a maximum by 6 to 8 days after infection . Thereafter, it decreased, reaching preinfection values about 4 weeks after inoculation . At the height of sensitivity, the animals were susceptible to less than 1 microgram of LPS compared with 100 or 200 micrograms in noninfected mice . The sensitization to LPS by infection was paralleled by a sensitization to tumor necrosis factor . The time course of development of sensitization to tumor necrosis factor, as well as the time course of its decrease and disappearance, was almost identical to that of LPS. Cancer Res, 1990 Apr 1, 50(7), 2036 - 43 Inactivation of 1,3-, 1,6-, and 1,8-dinitropyrene by cytochrome P-450 enzymes in human and rat liver microsomes; Shimada T et al.; NADPH-fortified human liver microsomes were examined with regard to ability to detoxicate several chemicals that do not require enzymatic oxidation to elicit a genotoxic response in a Salmonella typhimurium TA1535/pSK1002 system where umu response is used as an indicator of DNA damage . Microsomes did not affect the response seen with daunomycin, mitomycin C, 2,4,7-trinitro-9-fluorene, 1-nitropyrene, doxorubicin, 1-methyl-3-nitro-1-nitrosoguanidine, 2-nitrofluorene, or 1-ethyl-3-nitro-1-nitrosoguanidine (cited in order of decreasing umu response per mol) . Human and rat liver microsomes did inactivate 1,3-, 1,6-, and 1,8-dinitropyrene; with human liver microsomes the activity of 1,3-dinitropyrene