Mutat Res, 1992 Feb, 271(1), 89 - 96 Mutagenicity assay for nitroarenes of air pollutants held in leaves of woody plants; Suzuki J et al.; A new method was developed for the detection of mutagenic nitroarenes held in the leaves of woody plants using a small amount of leaves . This method consists of extraction of mutagen from fresh leaves (15-30 g) by ultrasonication with ethyl acetate and purification by elution with benzene on a silica gel column to remove such inhibitory components for mutagenesis as chlorophyll . The mutation assay uses the new Salmonella typhimurium strains YG1021 (a nitroreductase-overproducing strain of TA98) and YG1024 (an O-acetyltransferase-overproducing strain of TA98), which are very sensitive to some nitroarenes in the absence of S9, and standard strain YG1020 (TA98 containing pBR322-Aps) for comparison . This method was applied to woody plants growing on various sites in the Tokyo metropolitan area and the suburbs . It was shown that the leaves of all woody plants tested contained different amounts of mutagens, probably mutagenic nitroarenes, depending upon their growing sites. Mutat Res, 1992 Feb, 271(1), 1 - 12 Collaborative study using the preincubation Salmonella typhimurium mutation assay for airborne particulate matter in Japan . A trial to minimize interlaboratory variation; Matsushita H et al.; A collaborative study has been performed over a period of 3 years to develop a suitable method for monitoring the mutagenicity of airborne particulate matter . The study was organized with 8 laboratories and performed in the following steps: (1) selection of a suitable technique for each process involved in the mutagenicity monitoring, (2) developing a tentative protocol by combining systematically the selected techniques, (3) evaluation of the protocol by intra- and inter-laboratory studies, (4) modification of the protocol according to the evaluation, and (5) evaluation of the modified protocol by conducting an interlaboratory study . We found a suitable method for mutagenicity monitoring of particles in the atmosphere . Airborne particles were sampled with a high-volume sampler, the samples were stored at -80 degrees C, extracted by sonication using dichloromethane, solvent-exchanged, and assayed by the preincubation method using Salmonella typhimurium TA98 and TA100 . The observed mutagenic activity was normalized with that of an internal standard . Round robin tests revealed that the method resulted in excellent reproducibility . The coefficient of variation for mutagenic activities of airborne particulate samples collected in various districts of Japan were in the range of 14.7 +/- 6.6% to 19.6 +/- 4.0% for strains TA98 and TA100 with and without metabolic activation . We also found that the plate incorporation method was equivalent to the preincubation method for airborne particulate extracts. Mutat Res, 1992 Feb, 281(2), 143 - 7 Mutagenicity of pyrrolizidine alkaloids in the Salmonella typhimurium/mammalian microsome system; Rubiolo P et al.; The mutagenicity of a series of pyrrolizidine alkaloids, and of extracts from several Italian Senecio species containing pyrrolizidine alkaloids, including S . inaequidens, S . fuchsii and S . cacaliaster, were tested using the Salmonella typhimurium/mammalian microsome system . Retrorsine, senecivernine, seneciphylline and the Senecio extracts showed a weakly mutagenic activity. Mutat Res, 1992 Feb, 265(2), 263 - 72 Formation of genotoxic metabolites from anthraquinone glycosides, present in Rubia tinctorum L; Blomeke B et al.; Rubia tinctorum L., a medicinal plant used for the treatment of kidney and bladder stones, contains a characteristic spectrum of 9,10-anthraquinone derivatives, which are substituted in only one of the aromatic benzo rings . The majority of the anthraquinones present in the plant itself or in plant extracts are glycosides . We investigated the metabolism of two such glycosides, alizarinprimeveroside (AlP) and lucidinprimeveroside (LuP) . AlP given orally to rats was metabolized to alizarin (Al) and 1-hydroxyanthraquinone (1-HA) . The reductive cleavage of AlP was also observed after treatment of this compound with rat liver enzymes (S9) and NADPH . 1-HA has been reported to induce unscheduled DNA synthesis (UDS) in primary rat hepatocytes (PRH) and intestinal and liver tumors in rats after chronic treatment . The in vitro genotoxicity of 1-HA was confirmed by our present investigations . We also observed that the glycoside AlP was active at inducing UDS in PRH, but the compound was inactive in the Salmonella/microsome assay . Oral administration of LuP to rats resulted in the excretion of lucidin and rubiadin . When LuP was treated with rat liver extract and NADPH, the compound was reduced to rubiadinprimeveroside (RuP), which was hydrolyzed to rubiadin . We have recently shown that lucidin is highly genotoxic in a battery of short-term tests . We now report that rubiadin is also highly genotoxic in Salmonella typhimurium . However, in contrast to lucidin, it requires metabolic activation . In the UDS assay in PRH, rubiadin was even more potent than lucidin and equal to the positive control DMBA . In addition, the glycoside LuP is active in the Salmonella/microsome assay as well as in the UDS assay . The present work demonstrates that the uptake of the anthraquinone glycosides AlP and LuP leads to the rodent carcinogen 1-HA, and to the highly genotoxic compounds lucidin and rubiadin . This extends our previous studies and supports our suggestion that the therapeutic use of Rubia tinctorum may involve a carcinogenic risk. Mutat Res, 1992 Feb, 265(2), 181 - 93 Modulation of mutagenic properties in a series of DNA-directed alkylating agents by variation of chain length and alkylator reactivity; Ferguson LR et al.; Four series of aniline mustards linked to a DNA-affinic acridine chromophore by alkyl chains of varying length (2-5 carbon atoms) have been studied for their mutagenic properties, as estimated in four strains of Salmonella typhimurium and in Saccharomyces cerevisiae strain D5 . The four series have very different mustard reactivities, as determined by the aniline link group (-O-, -CH2-, -S- or -SO2-) . Some of the derived compounds cause frameshift mutagenesis which can be detected in TA98 and also "petite" mutagenesis activity, neither of which occur to significant extents with the parent mustards or with 9-aminoacridine . None of the derived compounds are as effective as the parent mustards in mitotic crossing-over, nor do they show ability for frameshift mutagenesis in S . typhimurium TA1977 which is typical of acridines . Some of the compounds have comparable frameshift activity to compounds such as ICR-191, but appear to have a different base-pair preference . The results indicate clear structure-activity relationships for the spectrum of mutagenic activity, which relate to both chain length and alkylator reactivity, for these compounds. Mutat Res, 1992 Feb, 265(2), 149 - 54 Modulating effect of tanshinones on mutagenic activity of Trp-P-1 and benzo{a}pyrene in Salmonella typhimurium; Sato M et al.; The modulating effects of the Chinese medicinal plant 'Tan-shen', the radix of Salvia miltiorrhiza Bunge, on the mutagenic activities of Trp-P-1 (3-amino-1,4-dimethyl-5H-pyrido{4,3-b}indole) and B(a)P (benzo{a}pyrene) were investigated using Salmonella typhimurium TA98 . Ether- and hot water-extracted 'Tan-shen' enhanced both mutagens at low concentrations, but suppressed them at high concentrations . Extracts by ether treatment were more effective than those extracted by hot water . Dihydrotanshinone I, cryptotanshinone, tanshinone I, and tanshinone IIA were isolated from the ether extract by high performance liquid chromatography (HPLC) and were recognized to be the mutagenic modulators . 4 tanshinones enhanced the mutagenicity of Trp-P-1 by 8-24-fold at 20 micrograms/plate and the enhancement was reduced at the higher concentration . Dihydrotanshinone I suppressed Trp-P-1 activity completely at 100 micrograms/plate. Infect Immun, 1992 Feb, 60(2), 491 - 6 Virulence of non-type 1-fimbriated and nonfimbriated nonflagellated Salmonella typhimurium mutants in murine typhoid fever; Lockman HA et al.; The virulence of Salmonella typhimurium mutants that were unable to synthesize type 1 fimbriae was tested in a murine typhoid fever model . Nonfimbriated mutants (fim) exhibited a lower 50% lethal dose than a wild-type (fim+) strain and produced significantly higher mortality (fim, 55%; fim+, 37% {P less than 0.002}) in mice that were challenged orally . There was no difference in virulence when the wild-type and mutant strains were injected intraperitoneally into mice . The progress of a short-term lethal infection was monitored after oral inoculation of mice with a mixture containing equivalent numbers of fim+ wild-type and fim mutant bacteria . The results indicated that while both strains colonized the intestinal tract equally well and invaded internal organs, the S . typhimurium fim mutant proliferated in the blood of the mice faster than the fim+ strain . The results of the mixed oral challenge suggested that bacteremia caused by fim+ S . typhimurium was reduced or delayed by the sequestration of the fimbriated bacteria in the spleen, liver, and kidneys . Thus, type 1 fimbriae were not virulence factors for S . typhimurium in this model, and the fimbriae may be an impediment to the pathogen in this setting . An S . typhimurium double mutant lacking type 1 fimbriae and flagella (fla) also was tested in mice . The virulence of the fim fla mutant was greatly reduced compared with that of the wild-type strain (mortality from fim fla challenge, 11% {P less than 0.0005}) . The significance of this latter result is discussed in relation to host adaptation by pathogenic salmonellae. FEMS Microbiol Immunol, 1992 Feb, 4(3), 147 - 53 Detection of porin antigen in serum for early diagnosis of mouse infections with Salmonella typhimurium; Muthukkumar S et al.; The monoclonal antibodies to porin, an outer membrane protein isolated from Salmonella typhimurium and sandwich enzyme linked immunosorbent assay (ELISA) has made possible the detection of porin from sera of S . typhimurium-infected mice . The specificity of the monoclonal antibodies was ascertained based on their cross-reactivity with porins isolated from S . typhi, Shigella flexneri and Escherichia coli and lipopolysaccharide (LPS) of S . typhimurium and E . coli . Serum samples were found to be positive for porin as early as 3 days after intravenous and 5 days after oral infection . In addition, a positive correlation was observed between the bacterial load and the concentration of porin detected in the sera . On the other hand, analysis of sera for anti-porin antibody showed diametrically opposite time kinetics with antigenaemia . These results indicate that porin accumulates in the serum of infected mice much earlier than the appearance of antibodies to porin . Thus detection of porin holds promise for early diagnosis of typhoid. Gene, 1992 Feb 1, 111(1), 43 - 9 Localization of the exonuclease and polymerase domains of Bacillus subtilis DNA polymerase III; Barnes MH et al.; Structural gene mutants were cloned and exploited to identify the major catalytic domains of Bacillus subtilis DNA polymerase III (BsPolIII), a 162.4-kDa {1437 amino acids (aa)} polymerase: 3'-5' exonuclease (Exo) required for replicative DNA synthesis . Analysis of the sequence, mutagenicity, and catalytic behavior of natural and site-directed point mutants of BsPolIII unequivocally located the domain involved in exonuclease catalysis within a 155-aa residue segment displaying homology with the Exo domain of Escherichia coli DNA polymerase I . Sequence analysis of four structural gene mutations which specifically alter then enzyme's reactivity to the inhibitory dGTP analog, 6-(p-hydroxyphenylhydrazino)uracil, and the inhibitory arabinonucleotide, araCTP, defined a domain (Pol) involved in dNTP binding . The Pol domain was in the C-terminal fourth of the enzyme within a 98-aa segment spanning aa 1175-1273 . The primary structure of the domain was unique, displaying no obvious conservation in any other DNA polymerase, including the distantly related PolIIIs of the Gram- organisms, E . coli and Salmonella typhimurium. Sci Total Environ, 1992 Jan 15, 111(2-3), 109 - 24 Analysis of the genotoxicity of municipal solid waste incinerator ash; Silkowski MA et al.; Combined bottom and fly ash obtained from a Chicago, IL, municipal solid waste incinerator (MSWI) was extracted with organic solvents, water or acidified water . The mean amounts of organic material isolated from each extraction procedure were 688.2, 91.8 and 167.7 micrograms/g MSWI ash . These extracts were evaluated for toxicity and mutagenicity in Salmonella typhimurium strains TA98 and TA100 . We developed and calibrated a micropreincubation assay to evaluate small concentrations of the organic extracts . No direct-acting mutagens were found, however the acid-treated aqueous extracts were toxic . Materials isolated with methylene chloride methanol were mutagenic after hepatic microsomal activation (S9) . The mutagenic potencies of the organic extract normalized to a per gram ash basis was the induction of 103.46 revertants in TA98 and 247.5 revertants in TA100 . The aqueous extracts were neither toxic nor mutagenic . However, the acid-treated aqueous extract was mutagenic to TA100 . The organic material isolated from the acidic extract had an induced mutagenic potency of 44.2 revertants/mg extract . Normalizing these data indicate a mutagenic potency of 7.4 revertants/g MSWI ash leached. Cancer Lett, 1992 Jan 10, 61(2), 129 - 34 The effect of ellagic acid on xenobiotic metabolism by cytochrome P-450IIE1 and nitrosodimethylamine mutagenicity; Wilson T et al.; Ellagic acid (EA) is an inhibitor of the in vitro mutagenicity of N-nitrosodimethylamine (NDMA) in Salmonella typhimurium strain TA100 using pyrazole-induced rat liver 9000 x g supernatant (S-9) . In order to understand this activity, the effect of EA on the metabolic hydroxylation of 4-nitrophenol, a substrate, as is NDMA, for cytochrome P-450IIE1 was studied using pyrazole induced rat S-9 and microsomal protein . It is shown that EA has an inhibitory effect on 4-nitrophenol hydroxylase with both enzyme preparations . This effect on cytochrome P-450IIE1 may be responsible, at least in part, for the inhibition of NDMA mutagenicity by EA. Biochim Biophys Acta, 1992 Jan 6, 1129(2), 228 - 30 The nucleotide sequence of leuB from Salmonella typhimurium; Andreadis A et al.; The nucleotide sequence and deduced polypeptide sequence of the Salmonella typhimurium leuB are reported, as well as a conserved region that might bind the enzyme substrate. Biochim Biophys Acta, 1992 Jan 6, 1129(2), 223 - 7 Completion of the nucleotide sequence of the 'maltose B' region in Salmonella typhimurium: the high conservation of the malM gene suggests a selected physiological role for its product; Schneider E et al.; We have subcloned and sequenced the genes malF and malM of Salmonella typhimurium, thereby completing the determination of the nucleotide sequence of its 'maltose B' regulon . The malM gene, encoding a periplasmic protein of unknown function in Escherichia coli, is a highly conserved as genes encoding proteins of known function from the same region. J Mol Biol, 1992 Jan 5, 223(1), 171 - 84 Substructure of the flagellar basal body of Salmonella typhimurium; Sosinsky GE et al.; The Salmonella typhimurium basal body, a part of the flagellar rotary motor, consists of four rings (denoted M, S, P and L) and a coaxial rod . Using low-dose electron microscopy and image averaging methods on negatively stained and frozen-hydrated preparations, we examined whole basal body complexes and subcomplexes obtained by dissociation in acid . Dissociation occurs in steps, allowing us to obtain images of substructures lacking the M ring, lacking the M and S rings, and lacking the M and S rings and the proximal portion of the rod . We obtained images of the L and P ring subcomplex . The existence of a subcomplex missing only the M ring suggests either that the S and M rings derive from two different proteins, or that the M ring is a labile domain of a single protein, which makes up both rings . At the 25 to 30 A resolution of our averaged images, the L, P and S rings appear cylindrically symmetric . Images of the M ring show variability that may be due to differences in angular orientation of the grid, but equally could be due to structural variations . Three-dimensional reconstructions of these structures from the averaged images reveal the internal structure and spatial organization of these components. J Mol Biol, 1992 Jan 5, 223(1), 27 - 30 Interdomain salt bridges modulate ligand-induced domain motion of the sulfate receptor protein for active transport; Jacobson BL et al.; The refined crystal structure of the liganded form of the Salmonella typhimurium sulfate-binding protein, a periplasmic receptor of active transport, is made up of two globular domains bisected by a deep cleft wherein the dehydrated sulfate is completely engulfed and bound by hydrogen bonds and van der Waals' forces . Two salt bridges (between Glu15 and Arg174 and between Asp68 and Arg134) span the cleft opening . To elucidate the role of the inter-domain salt bridges in the ligand-induced domain motion, the acidic residues were changed (singly and together) to their corresponding amide side-chains by site-directed mutagenesis of the recombinant Escherichia coli sulfate-binding protein . Rapid kinetics and equilibrium measurements of sulfate binding to the purified mutant proteins demonstrate that these salt bridges stabilize the closed liganded form of the receptor and modulate the rate of cleft opening . Our results have new implications in understanding the dynamics of many other multidomain proteins that undergo similar large-scale domain motions. J Clin Pathol, 1992 Jan, 45(1), 34 - 6 Salmonella bacteraemia in England and Wales, 1981-1990; Threlfall EJ et al.; AIMS: To report the incidence of nontyphoidal salmonellas in England and Wales and identified in the Division of Enteric Pathogens, London between 1981 and 1990 . METHODS: Strains were serotyped and phage typed for Salmonella typhimurium, S enteritidis, and S virchow, using established methods . RESULTS: Overall, less than 2% of nontyphoidal salmonellas isolated from humans were from blood culture . The highest numbers of bloodstream isolates were from infections caused by S enteritidis and S typhimurium, but the highest incidence of septicaemias was attributable to infections with S cholerae-suis, S dublin, and S virchow . 2.2% of S typhimurium isolates phage type 204C were from blood culture; likewise, 5.5% of S virchow phage type 19 . This could be a cause for concern as most isolates of both these phage types are multiresistant to antimicrobial drugs . CONCLUSIONS: Salmonella septicaemia is rare in England and Wales in other than a few serotypes of limited epidemiological importance. Mol Microbiol, 1992 Jan, 6(1), 47 - 57 Membrane topology of the integral membrane components, OppB and OppC, of the oligopeptide permease of Salmonella typhimurium; Pearce SR et al.; The oligopeptide permease of Salmonella typhimurium is a periplasmic binding protein-dependent transport system . Five gene products, OppABCDF, are required for the functioning of this transporter, two of which (OppB and OppC) are highly hydrophobic, integral membrane proteins and are responsible for mediating passage of peptides across the cytoplasmic membrane . OppB and OppC are each predicted, from their sequences, to span the membrane many times . In this paper we describe experimental evidence confirming these predictions using a combination of biochemical, immunological and genetic procedures . Each of these two proteins is shown to span the membrane six times, with the N- and C-termini both being located at the cytoplasmic face of the membrane . Opp is apparently a typical member of the ABC (ATP-binding cassette) superfamily of transporters . These findings, therefore, have general implications for the organization and function of other ABC transporters, including the human multidrug resistance protein and the product of the cystic fibrosis gene. Environ Mol Mutagen, 1992, 19(1), 53 - 70 Quantitative structure-activity relationship investigation of the role of hydrophobicity in regulating mutagenicity in the Ames test: 2 . Mutagenicity of aromatic and heteroaromatic nitro compounds in Salmonella Typhimurium TA100; Debnath AK et al.; A quantitative structure-activity relationship (QSAR) has been derived for the mutagenic activity of 117 aromatic and heteroaromatic nitro compounds acting on Salmonella typhimurium TA100 . Relative mutagenic activity is bilin-early dependent on hydrophobicity, with an optimal log P of 5.44, and is linearly dependent on the energy of the lowest unoccupied molecular orbital of the nitro compound . The dependence of mutagenic activity on hydrophobicity and electronic effects is very similar for TA98 and TA100 . Mutagenic activity in TA100 does not depend on the size of the aromatic ring system, as its does in TA9 . The effect of the choice of assay organism, TA98 versus TA100, on nitroarene QSAR is seen to be similar to the effect previously found for aminoarenes . Lateral verification of QSARs is presented as a tool for establishing the significance of a new QSAR. Environ Mol Mutagen, 1992, 19(1), 37 - 52 A QSAR investigation of the role of hydrophobicity in regulating mutagenicity in the Ames test: 1 . Mutagenicity of aromatic and heteroaromatic amines in Salmonella typhimurium TA98 and TA100; Debnath AK et al.; Quantitative structure-activity relationships (QSAR) have been derived for the mutagenic activity of 88 aromatic and heteroaromatic amines acting on Salmonella typhimurium TA98 + S9 and 67 amines acting on TA100 + S9 . Mutagenic activity is linearly dependent on hydrophobicity, the energy of the highest occupied molecular orbital, and the energy of the lowest unoccupied molecular orbital of the amine . The dependence of mutagenic activity on hydrophobicity and electronic effects is nearly identical for TA98 and TA100 . Mutagenic activity in TA98 is also found to depend on the size of the aromatic ring system . Different QSARs are derived for the mutagenic activity of hydrophilic amines (log P less than 1) acting on either TA98 or TA100 . The mechanism of amine activation and reaction with DNA is considered in light of these findings. Environ Mol Mutagen, 1992, 19(1), 14 - 20 Direct-acting mutagenic activity in white, rosé, and red wines with the Ara test of Salmonella typhimurium; Ariza RR et al.; Thirty-two commercially produced white, rose, and red wines from Spain were assayed for genotoxicity . The Ara forward mutagenicity assay with Salmonella typhimurium served as the test system . All the wines were mutagenic in the absence of mammalian microsomal activation (S9 mix) and/or glycosidase activities with the exception of one rose wine which gave a clear dose-response relationship, although its mutagenic potency was considered statistically nonsignificant . The mutagenic activity covered nearly a 30-fold range . Compared to white and rose wines, red wines showed the highest levels of mutagenicity; this wine type included four "very potent" (greater than 3,000 AraR mutants/ml) mutagenic wines . The level of wine mutagenicity did not correlate with either the region or the year of production (vintage) . Individual winery methods are suggested as primarily responsible for variations in mutagenic activity . The present study with the Ara test supports the possibility that wine components other than the flavonols quercetin and rutin are the major putative mutagens: (1) white wines, as well as rose or red wines, were detected as being mutagenic; (2) in no case was activation required for the detection of mutagenicity; (3) mutagen(s) were detected mainly (red wine) when not exclusively (white and rose wine) in the polar fraction from XAD-2 chromatography . The high sensitivity of the Ara test has allowed the screening of the mutagenicity of a variety of wines with no previous process of extraction or concentration . The comparison of the mutagenic activity of the entire complex mixture to that of its lyophilized residue has revealed a positive synergistic role for ethanol in the mutagenicity of certain wines . Finally, this work suggests that the Ara test is a useful tool for mutagenicity screening in wines . Thus, this test might play an important role in elucidating the genotoxic mechanism of action of alcoholic beverages, and for studying optional production methods to decrease the mutagenicity of commercial wines. J Bacteriol, 1992 Jan, 174(2), 643 - 5 Fumarate or a fumarate metabolite restores switching ability to rotating flagella of bacterial envelopes; Barak R et al.; Flagella of cytoplasm-free envelopes of Escherichia coli or Salmonella typhimurium can rotate in either the counterclockwise or clockwise direction, but they never switch from one direction of rotation to another . Exogenous fumarate, in the intracellular presence of the chemotaxis protein CheY, restored switching ability to envelopes, with a concomitant increase in clockwise rotation . An increase in clockwise rotation was also observed after fumarate was added to partially lysed cells of E . coli, but the proportion of switching cells remained unchanged. J Bacteriol, 1992 Jan, 174(2), 492 - 8 Molecular analysis of the Escherichia coli phoP-phoQ operon; Kasahara M et al.; The phoP-phoQ operon of Salmonella typhimurium is a member of the family of two-component regulatory systems and controls expression of the phoN gene that codes for nonspecific acid phosphatase and the genes involved in the pathogenicity of the bacterium . The phoP-phoQ operon of Escherichia coli was cloned on a plasmid vector by complementation of a phoP mutant, and the 4.1-kb nucleotide sequence, which includes the phoP-phoQ operon and its flanking regions, was determined . The phoP-phoQ operon was mapped at 25 min on the standard E . coli linkage map by hybridization with the Kohara mini set library of the E . coli chromosome (Y . Kohara, K . Akiyama, and K . Isono, Cell 50:495-508, 1987) . The predicted phoP and phoQ gene products consist of 223 and 486 amino acids with estimated molecular masses of 25,534 and 55,297 Da, respectively, which correspond well with the sizes of the PhoP and PhoQ proteins identified by the maxicell method . The amino acid sequences of PhoP and PhoQ of E . coli were 93 and 86% identical, respectively, to those of S . typhimurium. J Bacteriol, 1992 Jan, 174(2), 390 - 7 Regulation of the Salmonella typhimurium metA gene by the metR protein and homocysteine; Mares R et al.; The DNA sequence of the Salmonella typhimurium metA control region is presented . S1 nuclease mapping was used to determine the transcription initiation site . By measuring beta-galactosidase levels in Escherichia coli strains lysogenized with lambda phage carrying a metA-lacZ gene fusion, the MetR protein was shown to activate the metA gene . Homocysteine, an intermediate in methionine biosynthesis, plays a negative role in the MetR-mediated activation mechanism . Gel mobility shift assays and DNase I protection experiments showed that the MetR protein binds to a DNA fragment carrying the metA control region and protects a 26-bp region beginning 9 bp upstream of the -35 promoter sequence. J Bacteriol, 1992 Jan, 174(1), 84 - 91 The Salmonella typhimurium virulence plasmid complement resistance gene rck is homologous to a family of virulence-related outer membrane protein genes, including pagC and ail; Heffernan EJ et al.; A fragment of the Salmonella typhimurium virulence plasmid containing the rck locus, when cloned in the recombinant cosmid pADE016, was shown previously to confer high-level complement resistance on both rough and smooth Escherichia coli, Salmonella minnesota, and S . typhimurium and was associated with the production of an outer membrane protein . We determined the nucleotide sequence of the fragment containing the rck locus . Mutations in the two major open reading frames confirmed that the complement resistance mediated by pADE016 was due to a single 555-bp rck gene encoding a 17-kDa outer membrane protein . Analysis of the rck gene revealed that the Rck outer membrane protein consisted of 185 amino acid residues, with a calculated postcleavage molecular mass of 17.4 kDa . Rck is homologous to a family of outer membrane proteins expressed in gram-negative bacteria, two of which have been associated with virulence-related phenotypes: PagC, required by S . typhimurium for survival in macrophages and for virulence in mice; and Ail, a product of the Yersinia enterocolitica chromosome capable of mediating bacterial adherence to and invasion of epithelial cell lines . Rck, most closely related to PagC, represents the third outer membrane protein in this five-member family with a distinct virulence-associated phenotype. J Bacteriol, 1992 Jan, 174(1), 24 - 9 The CobII and CobIII regions of the cobalamin (vitamin B12) biosynthetic operon of Salmonella typhimurium; Escalante-Semerena JC et al.; A detailed deletion map of the CobII and CobIII regions of the cobalamin biosynthetic (cob) operon of Salmonella typhimurium LT2 has been constructed . The CobII region encodes functions needed for the synthesis of lower ligand 5,6-dimethylbenzimidazole (DMB); CobIII encodes functions needed for the synthesis of the nucleotide loop that joins DMB to the corrin macrocycle . The genetic analysis of 117 deletion, insertion, and point mutations indicates that (i) the CobII and CobIII mutations are contiguous--that is, they are grouped according to function; (ii) the CobII region is composed of four complementation groups (cobJKLM); (iii) cobM mutations do not complement mutations in any of the other three CobII groups; and (iv) CobIII mutations include three complementation groups that correspond to the cobU, cobS, and cobT genes. Environ Mol Mutagen, 1992, 20(1), 12 - 8 Molecular analysis of mutations induced by the intercalating agent ellipticine at the hisD3052 allele of Salmonella typhimurium TA98; DeMarini DM et al.; We have used DNA colony hybridization, the polymerase chain reaction (PCR), and direct DNA sequencing to determine the mutations induced by the intercalating agent ellipticine in Salmonella typhimurium TA98 in the presence of S9 . Of 400 ellipticine-induced revertants that were selected at a mutant yield that was ninefold over the background, 85.5% contained a GC or CG deletion within a common CGCGCGCG hotspot; this deletion occurred among 47% of the spontaneous revertants . In addition to this hotspot, the ellipticine spectrum contained two deletion warmspots that reside opposite each other in looped-out regions of a possible DNA secondary structure . Ellipticine and its metabolites likely revert Salmonella strain TA98 by forming DNA adducts that promote slippage-mismatches and by stabilizing these slipped mismatched sequences via intercalation . The involvement of these mechanisms, along with a likely role for DNA secondary structures and a possible role for DNA gyrase, may account for the site specificity exhibited by ellipticine in strain TA98. Mutagenesis, 1992 Jan, 7(1), 77 - 81 Study on the mutagenicity of brandy with the Ara test; Ariza RR et al.; The forward mutation assay to L-arabinose resistance (Ara test) in Salmonella typhimurium was used to demonstrate that evaporated residues of brandy had direct-acting mutagenic activity . The mutagenicity covered a 100-fold range, from 13482 to 127 AraR induced mutants/ml brandy equivalent . Rat liver S9 mix suppressed the mutagenic activity of brandy in the Ara test . The inactivating capacity was independent of microsomal monoxygenase enzymes and appeared to be mediated through a heat stable component of the S9 fraction . Catalase was identified as the putative S9 component responsible for its inactivating capacity . The implication of reactive oxygen species in the direct-acting mutagenicity of brandy was supported by the higher sensitivity of Escherichia coli bacterial strains deficient in two major cellular antioxidant defense (glutathione and/or catalase) compared to their parental wild-type . Phenolic compounds of a polar nature could be responsible for the mutagenicity through the production of reactive oxygen intermediates . Non-matured beverages (gin and non-matured rum) were non-mutagenic . It is conceivable that mutagenic phenolics might be extracted from the wood during maturation in the barrel . Autoxidation of phenolic compounds could be a common mechanism in the mutagenicity of complex mixtures of plant origin. Mutagenesis, 1992 Jan, 7(1), 37 - 9 Influence of the triazine ring on the mutagenicity of triazinoindoles and some congeners; Lopez-de-Cerain A et al.; Three compounds, which could be considered as precursors or derivatives of the 3-(4'-substituted-benzylidenamino)5H- 1,2,3-triazin{5,4b}indol-4-one series, were selected from the study of their mutagenic activity . Ames tests were performed study of their mutagenic activity . Ames tests were performed using the Salmonella typhimurium strains TA97, TA98, TA100, and TA102, according to the preincubation procedure, both with and without metabolic activation . The 3-amino-5H-1,2,3-triazin{5,4b}indol-4-one has been shown to be a strong S9-independent mutagen, which reverts frameshift and substitution mutations . Nevertheless its potency increases with the addition of microsomal fraction . In contrast, the 2-benzyliden-1-(3-aminoindol)-2-carbohydrazide and the 3-aminoindol-2-carbohydrazide congeners were not mutagenic . These results suggest that the 1,2,3-triazine ring is the principle substructure responsible for the mutagenicity of the triazinoindole congeners studied. Mutagenesis, 1992 Jan, 7(1), 31 - 5 Bacterial mutagenic evaluation of a series of 4' substituted derivatives of 3-benzylidenamino-5H-1,2,3-triazin{5,4b}indol-4-one; Garcia E et al.; The mutagenicity of ten triazinoindole derivatives was studied in bacteria . The compounds form part of a 3-(4'-substituted-benzylidenamino)-5H-1,2,3-triazin{5,4-b}in dol-4-one series and differ in the physicochemical properties of the substituent at the 4' position of the benzylidenamino group: -H, -OH, -COOH, -OCH3, -COOCH3, -NHCOCH3, -C1, -NO2, -C6H5, and -OC6H5 . They were tested in the TA97, TA98, TA100, and TA102 strains of Salmonella typhimurium, both with and without metabolic activation, using the preincubation procedure . Only the derivatives with phenyl and phenoxy substituents were non-mutagenic . The remaining compounds significantly increased the number of His+ revertants and showed three patterns of activity based upon their mutagenic potency and their response to metabolic activation . Size and hydrophobicity of the 4'-substituents are the physicochemical characteristics that most differentiate the mutagenic triazinoindole derivatives from the nonmutagenic ones. Mutagenesis, 1992 Jan, 7(1), 13 - 8 Sensitivity of Salmonella typhimurium TA97a to the type of agar used for preparation of Vogel-Bonner plates; Wilcox P et al.; Recent problems with the supply of Difco bacto agar have forced some laboratories to evaluate alternative agars for use in the Salmonella/microsome assay . This led to the independent observation in two laboratories (Boots and Glaxo) that Salmonella typhimurium TA97a is sensitive to certain types of agar that may be used to prepare Vogel-Bonner minimal medium plates . A programme of work was, therefore, undertaken to investigate this phenomenon; 9-aminoacridine hydrochloride (at Boots) and 4-nitro-o-phenylenediamine (at Glaxo) were tested against TA1537 and TA97a using Vogel-Bonner plates prepared with a number of different agars . Three agars (Lab M, Difco Bi-tek and Beckton Dickinson granulated) were identified which, although supporting normal growth of TA1537 revertant colonies, gave much reduced control counts and responses to the mutagens with TA97a . One agar, Becton Dickinson grade A, gave poor responses with TA1537 but produced satisfactory results with TA97a . In contrast to the Vogel-Bonner plates, varying the type of agar used in the top agar overlays had little effect on the responses obtained . On the basis of these comparisons, Becton Dickinson purified agar was selected as a suitable alternative to Difco bacto and it was concluded that laboratories using agars other than these, or purchasing pre-poured plates without specifying the type of agar, should be made aware of potential problems with TA97a. J Cancer Res Clin Oncol, 1992, 118(6), 447 - 52 Protective role of aqueous turmeric extract against mutagenicity of direct-acting carcinogens as well as benzo {alpha} pyrene-induced genotoxicity and carcinogenicity; Azuine MA et al.; Turmeric (Curcuma longa Linn.) has been shown to inhibit chemical carcinogenesis . In this study, we compared the chemopreventive efficacy of an aqueous turmeric extract (AqTE) and its constituents, curcumin-free aqueous turmeric extract (CFAqTE) and curcumin, using the Salmonella typhimurium mutagenicity assay and the bone marrow micronucleus test in female Swiss mice . AqTE exhibited antimutagenic activity against direct-acting mutagens, 4-nitro-O-phenylenediamine and 1-methyl-3-nitro-1-nitrosoguanidine, in strains TA 98 and TA 100 respectively . Both AqTE and CFAqTE inhibited the mutagenicity of benzo {alpha}pyrene in the two strains in the presence of Aroclor-1254-induced rat liver homogenate . The inhibition in both studies was dose-dependent . Administration of AqTE, CFAqTE and curcumin at a dose of 3 mg/animal 18 h prior to i.p . benzo {alpha}pyrene injection (250 mg/kg) significantly inhibited bone marrow micronuclei formation in female Swiss mice by 43%, 76%, and 65% respectively . Furthermore, the incidence and multiplicity of forestomach tumours induced by benzo {alpha}pyrene (1 mg/animal, twice weekly, p.o . for 4 weeks) in female Swiss mice were significantly inhibited by AqTE, CFAqTE and curcumin given 2 weeks before, during and after the carcinogen treatment . These data indicate that the protection against genomic damage by turmeric extract and its components tested could be necessary for some aspects of its cancer chemoprevention. Environ Mol Mutagen, 1992, 19(4), 338 - 45 Mutagenicity of beta-alkyl substituted acrolein congeners in the Salmonella typhimurium strain TA100 and genotoxicity testing in the SOS chromotest; Eder E et al.; The beta-alkyl substituted acrolein congeners crotonaldehyde, trans-2-pentenal, trans-2-hexenal, 2,4-hexadienal, and trans-2-heptenal were clearly mutagenic in a slightly modified preincubation Ames test with Salmonella typhimurium TA100 with and without S9 mix using a threefold bacterial cell density and a 90-min preincubation time, whereas trans-cis-2,6-nonadienal did not show any mutagenic activity . The greatest impediment to adequate mutagenicity testing of these compounds is their toxicity toward bacteria . Within the congener family tested, toxicity increases as a function of both chain length and lipophilicity, and it becomes more and more difficult to demonstrate mutagenicity . Mutagenicity decreases with increasing chain length . This effect may be explained by increasing toxicity . The effect of S9 mix seems to be mostly nonenzymatic detoxication by nonspecific scavanger protection of bacterial cytotoxicity . No indication could be found that bioactivation plays a role in S9-mediated reduction of bacterial cytotoxicity . Although positive mutagenic outcomes could be obtained with the SOS chromotest for other alpha, beta-unsaturated carbonyl compounds, these acrolein congeners were not genotoxic in this test, most probably because they are toxic for the Escherichia coli bacteria PQ37 and PQ243. Environ Mol Mutagen, 1992, 19(4), 331 - 7 Ozone is mutagenic in Salmonella; Dillon D et al.; Ozone is a highly reactive gas that has been tested for genotoxicity in a number of systems . Induced genetic damage resulting from ozone treatment may not be readily observed because of the high toxicity of the chemical and difficulties in generating and administering controlled concentrations . The mutagenicity of ozone was investigated in Salmonella typhimurium using a plate test protocol designed for reactive vapours and gases . Ozone, at two to three consecutive doses, induced weak, albeit statistically significant, mutagenic responses in tester strain TA102 with and without Aroclor-induced rat liver S9 (lowest effective mean concentration of 0.019 ppm; 35 min total exposure) . However, dose-related responses were not always obtained . No mutagenicity was detected in strains TA98, TA100, or TA1535, with or without S9 . In strain TA104, ozone induced a weak response only at a single dose with S9; this response was not reproducible . Mutagenicity was dependent on the ozone flow rate and total exposure time, with variations in the optimum dose-time regimen leading to toxicity or complete inactivity . The data show that ozone is a very weak bacterial mutagen and only when tested under narrowly prescribed, subtoxic dosing conditions. Environ Mol Mutagen, 1992, 19(4), 311 - 5 Structure-activity relationship in the mutagenic effect of chiral or racemic 2-bromo-propanamides on Salmonella typhimurium; Dolzani L et al.; Some 2-bromo-propanamides were prepared and tested for direct mutagenicity in Salmonella typhimurium TA 100 . Results confirm the mutagenic activity of 2-bromo-N-benzyl-propanamide and indicate that it is independent of enantiomeric configuration . A variation in the chemical structure, namely, the addition of a methyl group at the benzylic carbon, causes the four resulting diastereomers to be devoid of any activity . Conversely, some racemic ring-substituted methoxy and/or hydroxy derivatives of the parent compound displayed mutagenic properties, causing an increase in the number of his+ revertants up to 524 per milligram per plate. Indian J Med Res, 1992 Jan, 95, 17 - 20 Salmonella typhimurium enterotoxin mediated fluid secretion; Khurana S et al.; Unidirectional Na+ and Cl- fluxes were studied in rats treated with S . typhimurium enterotoxin (S-LT) . There was net absorption of Na+ and Cl- in the control group, while in the toxin treated animals there was net secretion of Na+ and Cl- (P less than 0.001) . There was no change in the transport of D-glucose in the toxin treated group as compared to the control animals . The Na+, K(+)-ATPase pump was unaltered in the S-LT treated animals (198.67 +/- 11.23 nmoles Pi/mg protein/min) as compared to the control group (189.93 +/- 10.09 nmoles Pi/mg protein/min) . There was no change in the unidirectional fluxes of Ca+2 in the S-LT treated animals as compared to the control animals, suggesting no change in the permeability of the S-LT treated intestinal membrane to Ca+2. Vaccine, 1992, 10(5), 337 - 40 Prophylaxis of Salmonella abortus ovis-induced abortion of sheep by a Salmonella typhimurium live vaccine; Linde K et al.; A Salmonella typhimurium live vaccine with optimal level of attenuation for sheep, constructed by means of 'metabolic drift' mutations, was tested for its efficacy in preventing Salmonella abortus ovis-induced abortions . In two field trials in Kirgiziya, 78,000 to 100,000 first delivery sheep received a fully tolerated single dose of 10(9) c.f.u . live vaccine 2 months before to 4 months after insemination . Alternatively, they were immunized twice with commercial inactivated S . abortus ovis vaccine, or they served as non-immunized controls . The S . abortus ovis-induced abortion frequency in the controls was greater than or equal to 30%, in sheep immunized with inactivated vaccine greater than or equal to 11% . In flocks immunized with live vaccine, the S . abortus ovis-induced abortion frequency did not exceed 0.1% . Thus, use of 'metabolic drift' mutations for construction of stable vaccine strains optimally attenuated for the particular host species proved to be relevant to practice. Eur J Epidemiol, 1992 Jan, 8(1), 120 - 1 Human salmonellosis transmitted by a domestic turtle; Dessi S et al.; Salmonella typhimurium was isolated in the culture test of a small child admitted to hospital suffering from febrile gastroenteritis with stools containing traces of mucus and blood . Her mother also resulted positive for this microorganism . The family had recently bought a small turtle, imported from Florida, at the city fair . Further tests revealed Salmonella typhimurium in both the turtle's feces and the water in its tank. Environ Mol Mutagen, 1992, 19(3), 253 - 8 Mutagenicity of benzo(a)pyrenyl-1-sulfate in the Ames test; Irwin SE et al.; Comparison of the mutagenicity of nine isomeric benzo(a)pyrenyl {B(a)P} phenols conjugated with either sulfate or glucuronide was carried out using strain Salmonella typhimurium TA98 . Of the nine conjugates tested, only B(a)P-1-sulfate was mutagenic . Accordingly, the mutagenicity of B(a)P-1-sulfate was compared with that of B(a)P and 1-hydroxybenzo(a)pyrene {B(a)P-1-OH} in the presence and absence of rat lung S9 and Aroclor-induced liver S9 with and without an NADPH-generating system . B(a)P-1-sulfate was slightly mutagenic, whereas B(a)P and the 1-hydroxy derivative were nonmutagenic when S9 fractions and NADPH were omitted . Addition of induced liver S9 with NADPH caused mutagenicity with B(a) -1-OH greater than B(a)P greater than B(a)P-1-sulfate . B(a)P-1-sulfate was the only mutagenic species when lung S9 was added . This mutagenicity did not require NADPH . Sodium sulfite, an inhibitor of arylsulfatase, decreased the mutagenicity of B(a)P-1-sulfate . These data suggest that a unique mutagenic species is generated from B(a)P-1-sulfate via arylsulfatase in rat lung. Environ Mol Mutagen, 1992, 19(3), 244 - 52 Effects of plate preparation on results in microbial mutation assays; Majeska JB et al.; Glucose autoclaved in an alkaline phosphate solution (heated glucose+salts, HGS) results in the production of a moiety that is nonmutagenic but can interact with a series of 4-{2-(aryl)ethenyl}-2,6-dimethylphenols to result in an increase in bacterial revertants that is dependent on the amount of HGS in the minimal agar plates . The reaction between the HGS and the chemical to form a mutagen is independent of the presence of bacteria, does not result in a nutritive analog to enhance growth of the auxotrophic bacteria, and is effective only in Salmonella typhimurium and Escherichia coli strains that contain the plasmid pKM101 . A sufficient amount of this glucose product may be formed in normal plate preparation to produce apparent mutagenic activity of these chemicals. Avian Dis, 1992 Jan-Mar, 36(1), 24 - 9 Reaction of the avian respiratory system to intratracheally administered avirulent Salmonella typhimurium; Toth TE et al.; Chickens were inoculated intratracheally (IT) with the SR-11 Salmonella typhimurium deletion mutant x4062 strain . Data collected for 8 days postinoculation (PI) were: signs of respiratory and gastrointestinal disease; histological lesions; the influx, phagocytic proportion, and phagocytic capacity of avian respiratory phagocytes (ARPs); and the proportion of granulocytes vs . macrophages in the lung tissues and lavage fluids of the lungs and air sacs . S . typhimurium-inoculated chickens had no clinical signs of gastrointestinal or respiratory disease but had various degrees of inflammatory changes in the lungs . At 5 hr PI, S . typhimurium-inoculated chickens had approximately 53-fold more ARPs than mock-inoculated controls . Between 26 hr and 8 days PI, the number of ARPs from S . typhimurium-inoculated birds was not significantly higher than the number from the mock-inoculated controls . Flow cytometric analysis of ARPs demonstrated that the proportion of phagocytic ARPs and the phagocytic capacity of ARPs from S . typhimurium-inoculated chickens were significantly higher between 5 and 26 hr PI than those of the ARPs from mock-inoculated chickens . Kinetic changes over 8 days in the granulocyte/macrophage ratios in the lavage fluids, as compared with kinetic changes in the lung tissues, suggested that the granulocytes generally represent a much higher proportion of the ARPs, and egress earlier and in much larger numbers from the tissues to the lumen of lungs and air sacs than do macrophages. Avian Dis, 1992 Jan-Mar, 36(1), 139 - 42 Effect of feeding selected short-chain fatty acids on the in vivo attachment of Salmonella typhimurium in chick ceca; McHan F et al.; Two groups of 20 chicks each were fed 1% fatty acid continuously starting at 1 day of age, while a control group of 20 chicks received unsupplemented feed . At 2 days of age, chicks were inoculated orally with 1 ml of Salmonella typhimurium (1 x 10(6) colony-forming units/ml) . Ceca were obtained from six chicks of each group at 7, 14, and 21 days of age . At 14 days of age, formic and propionic acids had statistically reduced Salmonella recovery by 2.56 logs and 3.09 logs, respectively, compared with controls . At 21 days of age, both test groups showed significant reductions of approximately 3.6 logs compared with controls . There were no statistical differences in body weights among the groups at 21 days of age. Environ Mol Mutagen, 1992, 19 Suppl 21, 2 - 141 Salmonella mutagenicity tests: V . Results from the testing of 311 chemicals; Zeiger E et al.; 311 chemicals were tested under code, for mutagenicity, in Salmonella typhimurium; 35 of the chemicals were tested more than once in the same or different laboratories . The tests were conducted using a preincubation protocol in the absence of exogenous metabolic activation, and in the presence of liver S-9 from Aroclor-induced male Sprague-Dawley rats and Syrian hamsters . Some of the volatile chemicals were also tested in desiccators . A total of 120 chemicals were mutagenic or weakly mutagenic, 3 were judged questionable, and 172 were non-mutagenic . The remaining 16 chemicals produced different responses in the two or three laboratories in which they were tested . The results and data from these tests are presented. Environ Mol Mutagen, 1992, 19(2), 167 - 81 Evaluation of the mutagenic and genotoxic activities of 48 nitroimidazoles and related imidazole derivatives by the Ames test and the SOS chromotest; De Meo M et al.; The mutagenic and genotoxic activities of 48 nitroimidazoles and related imidazole derivatives have been evaluated by using modified versions of the Ames test and the SOS Chromotest . Salmonella typhimurium tester strain TA 100 was used with and without metabolic activation in the Ames test and Escherichia coli tester Strain PQ 37 was used with and without metabolic activation in the SOS Chromotest . Including metronidazole and dimetridazole, 45 derivatives were mutagenic and genotoxic . The mutagenic potencies (MP) ranged from 0.127 to 53,717 revertants/nmol while the SOS induction powers (SOSIP) ranged from 0.00131 to 107 IF/nmol . The overall correlation between MP and SOSIP was r = 0.845 (n = 84) as calculated by linear regression analysis . A higher correlation was observed between MP and SOSIP without the S9 mix than with it . Among the imidazole derivatives, the 5-nitroimidazoles with a lactam ring at the 2-position showed the highest MP and SOSIP . The presence of a nitro group at the 5-position was critical for the mutagenicity and the genotoxicity of the derivatives . Substituents at the 1- and 2-positions were also found to modulate these activities. Environ Mol Mutagen, 1992, 19(2), 139 - 46 Conditions for detecting the mutagenicity of divalent metals in Salmonella typhimurium; Pagano DA et al.; The mutagenesis of metals in bacteria, as reported in the literature, can best be described as inconsistent . We report that cobalt chloride (Co++), ferrous sulfate (Fe++), manganese sulfate (Mn++), cadmium chloride (Cd++), and zinc chloride (Zn++) could be reproducibly detected as mutagens in Salmonella strain TA97 when preincubation exposures were made in sterile, distilled, deionized water, or in Hepes buffer in NaCl2/KCl2, rather than the standard sodium phosphate buffer . Co++ was also mutagenic under standard preincubation conditions . The individual components of Vogel-Bonner medium, i.e., potassium and ammonium phosphate, citrate, and magnesium sulfate, inhibit mutagenesis by these metals . The phosphates and the citrate probably inhibit by chelating the metals, while data are presented to suggest that Mg++ inhibition of metal mutagenesis is due to competitive inhibition for active transport via the magnesium active transport system in Salmonella . The chelator, diethyldithiocarbamate, inhibited the mutagenicity of Co++, Fe++, Zn++, and Mn++, but enhanced the mutagenicity of Cd++ . The results presented show that divalent metals can be detected as mutagens in Salmonella, and that their lack of detection as mutagens is not due to an inherent insensitivity of Salmonella but to their interaction with media components and/or passive and active transport processes. Environ Mol Mutagen, 1992, 19(2), 112 - 24 Metal, mutagenicity, and biochemical studies on bivalve molluscs from Spanish coasts; Rodriguez-Ariza A et al.; Three species of marine bivalve molluscs (Chamelea gallina, Ruditapes decussatus, and Crassostrea gigas) have been studied in order to evaluate the levels of pollution on the South Atlantic Spanish littoral . Several transition metals (Cu, As, Cd, Sn, Hg, Pb) were determined as a general index of total contamination . Animals from putative contaminated areas exhibited higher metal contents than those from cleaner waters . C . gigas showed 5-20-fold higher total metal content than the other two species . The mutagenicity of ethanolic extracts was assayed by using both the His reversion and the Ara forward mutation tests . Mollusc tissues from the three species did not contain genotoxins active on TA98 (frameshift mutations) or TA100 (mainly G:C base-pair substitutions), but did contain direct-acting genotoxins of a polar nature and oxidative type . This was based on the following observations: 1) mammalian metabolic activation was not required for mutagenicity, 2) mutagens were eluted with the polar fraction from XAD-2 columns, and 3) mutagenic responses were observed with Salmonella typhimurium TA102 (A:T base-pair substitutions; sensitive to oxidative damages) and Escherichia coli catalase-deficient (AraR forward mutations) strains . No relevant differences were found in the mutagenicity of mollusc extracts from areas with different pollution levels . Otherwise, our data suggest that, in general, animals living in contaminated environments had fewer genotoxins of oxidative type than those from less polluted areas . Such a result might be explained by the observation of increased levels of a number of detoxifying and antioxidant enzymes, such as glutathione-S-transferase, glutathione-peroxidase, catalase, and superoxide dismutase . Thus, contaminated animals seem to be better protected against the oxidative damages induced by metals, in agreement with their lower malondialdehyde levels . To what extent the responsible mutagenic compounds are of endogenous origins, or "Nature's pesticides" (the major toxic chemicals ingested by phytoplankton filter-feeders), and/or the result of human activities remains to be determined. Vaccine, 1992, 10(1), 61 - 6 Humoral and cell-mediated immunity in mice after immunization with live oral vaccines of Salmonella typhimurium: auxotrophic mutants with two attenuating markers; Mitov I et al.; Persistence and clearance of the vaccinal strains, humoral and cell-mediated immune response and protective immunity were assessed in ICR mice, immunized intraperitoneally or intragastrically with double-marker auxotrophic mutants of Salmonella typhimurium strains 1771 and 3334 (his-pur-) . Strain 3334 possesses in addition the antiepidemic Hst (high sensitivity to tensides) marker which confers decreased survival in the gut and environment . The results showed that the strains are not overattenuated . They revealed preserved multiplication capacity, established carrier state for 28-30 days and induced humoral and cell-mediated immunity as measured by passive haemolysis and microagglutination or footpad swelling tests, respectively . The immune response was determined by biological features of the strains . Strain 1771 induced synthesis of O- and H-antibodies 7-11 days earlier than strain 3334 . Footpad reactions appeared 3-4 days after immunization and a week before the serum antibodies . Cell-mediated immunity showed clear correlation with the protection against challenge with a virulent strain . The present results suggest that the double-marker auxotrophic mutants of S . typhimurium might prove very useful in the development of a live vaccine in further studies on livestock. Poult Sci, 1992 Jan, 71(1), 59 - 63 Influence of coccidiosis on Salmonella colonization in broiler chickens under floor-pen conditions; Arakawa A et al.; The influence of coccidiosis on colonization of Salmonella typhimurium in broiler chickens under floor pen conditions was studied by semiquantitative methods . Chickens of two groups, unmedicated and medicated with nicarbazin (125 ppm via the feed), were exposed to three species of Eimeria (Eimeria tenella, Eimeria maxima, and Eimeria acervulina) at 2, 3, and 4 wk of age and given S . typhimurium in the feed 2 days later . Salmonella typhimurium was isolated most often (100%) from ceca of chickens exposed at 3 wk of age . Birds in the unmedicated group were positive for S . typhimurium at a higher rate than those in the medicated group . Salmonella typhimurium was detected in livers only in a few unmedicated birds. Metabolism, 1992 Jan, 41(1), 1 - 2 Fish oil decreases natural resistance of mice to infection with Salmonella typhimurium; Chang HR et al.; Mortality rate in mice fed fish oil for 4 weeks was remarkably higher after a very low peroral (PO) challenge with Salmonella typhimurium, as compared with those fed diets rich in either corn oil or hydrogenated coconut oil, or a low fat (chow) diet . None of the surviving mice fed the fish oil diet showed bacterial counts in their spleens, unlike 45.4% to 66.6% of surviving mice fed high fat or low fat diets . The spleens of mice fed fish oil presented the highest number of bacteria 7 days after intraperitoneal infection with the same bacterial strain . Thus, the current studies demonstrate that a diet rich in fish oil decreases host resistance to infection. FEMS Microbiol Lett, 1992 Jan 1, 69(2), 101 - 4 The role of ntrA in the anaerobic metabolism of Salmonella typhimurium; Fasciano A et al.; The possible involvement of NtrA in the expression of several anaerobically induced genes in Salmonella typhimurium was investigated . Unlike Escherichia coli, where hydrogenase 3 is ntrA dependent, the introduction of a mutation in ntrA had virtually no effect on the hydrogenase activity, thought to be hydrogenase 3, of S . typhimurium LT7 . Fumarate reductase and alcohol dehydrogenase activities were found to be diminished in ntrA mutant strains, but this may very well be indirect since fdhF mutant strains showed the same effect . These results suggest that in S . typhimurium NtrA is highly specific for the anaerobic expression of fdhF. J Bacteriol, 1992 Jan, 174(2), 486 - 91 Molecular genetic analysis of the Escherichia coli phoP locus; Groisman EA et al.; We have cloned the Escherichia coli phoP gene, a member of the family of environmentally responsive two-component systems, and found its deduced amino acid sequence to be 93% identical to that of the Salmonella typhimurium homolog, which encodes a major virulence regulator necessary for intramacrophage survival and resistance to cationic peptides of phagocytic cells . The phoP gene was mapped to kilobase 1202 on the Kohara map (25-min region) of the E . coli genome (Y . Kohara, K . Akiyama, and K . Isono, Cell 50:495-508, 1987) and found to be transcribed in a counterclockwise direction . Both E . coli and S . typhimurium phoP mutants were more sensitive than their isogenic wild-type strains to the frog-derived antibacterial peptide magainin 2, suggesting a role for PhoP in the response to various stresses in both enteric species. Free Radic Res Commun, 1992, 16(1), 1 - 10 Clastogenic and mutagenic actions of active species generated in the 6-hydroxydopamine/oxygen reaction: effects of scavengers of active oxygen, iron, and metal chelating agents; Gee P et al.; A pro-oxidant triphenol, 6-hydroxydopamine (6-OHDA), induced mutations in the Salmonella typhimurium TA 104 tester strain (over the concentration range to 800 microM), and induced chromosomal aberrations in cultured Chinese hamster ovary (CHO) cells at lower concentrations (up to 90 microM) . It was however only marginally mutagenic (up to cytotoxic levels of 200 microM) in the TA102 tester strain . Clastogenicity in the more sensitive CHO cell assay was mediated by activated oxygen . Superoxide dismutase decreased the incidence of chromosomal aberrations by 60% and catalase (or superoxide dismutase plus catalase) decreased the incidence to control levels . The clastogenicity of 6-OHDA was dependent upon unsequestered transition metal ions, since addition of EDTA plus desferrioxamine decreased chromosomal aberrations by 90% . The simplest explanation of the data is that genotoxicity is mediated by active species generated in a Fenton-type reaction between 6-OHDA and H2O2 catalyzed by traces of metals in the medium. Folia Microbiol (Praha), 1992, 37(3), 188 - 92 Comparison of permuted region lengths in the genomes of related Salmonella typhimurium phages P22 and L; Spanova A; Lengths of permuted regions in the P22 and L phage genomes were estimated from the relative yields of DNA in many electrophoretic bands obtained using several restriction endonucleases . It was found that 3.6 kb (8.7%) of P22-DNA and 7.2 kb (17.8%) of L-DNA were circularly permuted . In both phages the sequential packaging process proceeded in the same direction and four headful-size DNA molecules were, on the average, cleaved in one packaging series . The differences in circular permutation may originate from different genome lengths because their average headful portions are very similar (42.5 kb in P22 and 42.3 kb in L). Infection, 1992, 20 Suppl 2, S84 - 92 The role of GM-CSF in infection; Freund M et al.; GM-CSF is a hemopoietic growth factor with substantial effects on the proliferation of neutrophils, eosinophils and monocytes/macrophages . Its physiologic role in infection is still poorly understood . The gene for GM-CSF is constitutively transcribed in cells substantial for antiinfectious response . Various cells are activated and induced by TNF and IL-1 to synthesize GM-CSF . No systemic GM-CSF levels can be detected in patients with infection . It is likely that GM-CSF plays its physiological role in the immediate vicinity of the cells by which it is secreted . GM-CSF functionally activates neutrophils, monocytes/macrophages and eosinophils . It may augment T-cell proliferation and function . GM-CSF is effective in mice infected with Staphylococcus aureus or Salmonella typhimurium . Its effect in infectious disease in man should be explored. Sb Ved Pr Lek Fak Karlovy Univerzity Hradci Kralove Suppl, 1992, 35(3), 219 - 42 {Genotoxic activity test of sodium fluoride in vitro}; Srb V et al.; The artificial drinking water fluoridization provided as a mass preventive measure against dental decay poses another substantial problem which is a possibility of genotoxic action . Up to this date, this matter remains still obscur and is discussed with more or less intensity from time to time . The mentioned fact supported authors to study the impact of short-term 24 hrs sodium fluoride (NaF) action in concentration range of 0-500 mg.1(-1) drinking water in the frame of so-called minimal testing set (analysis of chromosomal aberrations in human peripheral lymphocytes, Ames test) . For the initial NaF concentration applied, the reference value of 1 mg per 1 liter artificial fluoridization was estimated . The use of Ames test with TA 98 and TA 100 Salmonella typhimurium (+/- S9) strains showed no significant increase in revertants responsible of NaF mutagenic activity in any of applied concentrations (0-1300 mg per 1 Petri dish; = 0-520 mg.l-1 converted to the basic supplementative dose) . Cytogenetic analysis of peripheral lymphocytes showed more sensitivity than prototrofic salmonella test . Yet one order higher NaF concentration than its application norm 1 mg.l-1 (i.e . 11 mg.l-1) has induced the occurrence of 3.8% ABB after single addition for 24 hrs to the "healthy" blood cultivated in vitro at short-term . This accounts for a value close to the level of statistically significant difference with regard to the application norm recommended . This level has been even exceeded as for a total count of fragments and exchanged parts . Thus the two orders higher NaF concentration (110.0 mg.l-1) resulted in a strong increase of cells with chromosomal aberrations for all of indicators observed; e.g . 27.5% ABB . Based on literary sources, obtained results and properly experience in practical proceeding artificial fluoridation, the authors concluded that the latter is not adequate to the up-to-date status of knowledge . Besides of economical and technical problems, those scientific are mainly concerned with making doubtful the auto-presumed genotoxic inertness for chronic users of fluoridated drinking water . Author's opinion is that when necessarily provided, the artificial fluoridization of drinking water should be proceeded selectively (in accord with real requirements of an appropriated population group, its age structure and location), temporarily and with intermittent checkout of fluoridization application regimen . To conclude, authors recommend further observation with use of biological model situations in vivo. Zh Mikrobiol Epidemiol Immunobiol, 1992, (9-10), 50 - 7 {Protection from virulent Salmonella groups B and D after the peroral immunization of chicks with a hybrid of Salmonella typhimurium and Salmonella dublin}; Polotskii IuE et al.; Chickens over 10 days old, infected orally with virulent salmonellae, were found to remain alive . Histologic investigation showed the development of mild enteritis and more pronounced, lasting for more than two weeks, inflammation of the cecum, dissemination and focal lesions in the liver (granulomas, necrosis) . In experiments on the oral immunization of 3-day old chickens the bivalent hybrid of S . typhimurium vaccine strain 274 and S . dublin induced only pronounced blast transformation in lymphatic follicles of the cecum, hyperplasia of activated macrophages and formation of granulomas from these macrophages and lymphocytes . After oral challenge of the immunized chickens with virulent salmonellae of group B (S . typhimurium) and group D (S . enteritidis, S . gallinarum-pullorum) the chickens exhibited sharply pronounced protection against adhesion, colonization and invasion, and a few penetrating bacteria were rapidly destroyed by immune macrophages . Hybrid strain 274/O9 proved to be suitable for use as oral bivalent vaccine against salmonellosis in chickens. Yi Chuan Xue Bao, 1992, 19(4), 362 - 8 {Isolation of vitamin B2 auxotroph and preliminary genetic mapping in Salmonella typhimurium}; Wang A; The first independent vitamin B2 auxotrophs of Salmonella typhimurium were obtained by using selective medium containing extraordinarily high concentration of B2 (300 micrograms/ml) after mutagenesis . Transduction analysis showed that 21 B2 auxotrophs could be divided into four groups, which were unlinked to each other . It means that at least 4 structural genes were involved in B2 biosynthetic pathway . Preliminary genetic mapping indicated that 2 genes located in 7'-22' and other 2 located in 22'-34' and 61.5'-69' region on the genetic map of S . typhimurium respectively. Zh Mikrobiol Epidemiol Immunobiol, 1992, (7-8), 42 - 5 {The evaluation of the mutagenic activity of pertussis vaccinal preparations}; Bolgareva GM et al.; Two vaccine preparations obtained from Bordetella pertussis, whole-cell vaccine constituting one of the components of adsorbed DPT vaccine and acellular vaccine, were tested for mutagenicity . The doses of the preparations covered the range 1-100 ED50 . Ames' test and the metaphase analysis of marrow cells of C57BL/6J mice were used . The acellular preparation was also tested on thymectomized mice, taking into consideration chromosomal aberrations in marrow metaphases . Whole-cell and acellular pertussis vaccines did not induce mutations in Salmonella typhimurium and chromosomal aberrations in mouse marrow cells. Nutr Cancer, 1992, 17(3), 287 - 95 Antimutagenic and anticarcinogenic effects of carotenoids and dietary palm oil; Azuine MA et al.; Four carotenoids, canthaxanthin, beta-carotene, 8H-apo-beta-carotenal, and 8'-apo-beta-carotene methylester were tested for their ability to suppress the mutagenicity of 1-methyl-3-nitro-1-nitrosoguanidine and benzo{a}pyrene (BP) in Salmonella typhimurium tester strain TA 100 . The anticarcinogenic efficacy of the four carotenoids was further assessed in the BP-induced forestomach tumor model in female Swiss mice . The effect of dietary palm oil was also examined in BP-induced neoplasia in the female Haffkine Swiss mouse strain . Canthaxanthin, beta-carotene, 8'-apo-beta-carotenal, and 8'-apo-beta-carotene methylester showed a dose-dependent decrease in the mutagenicity compared with 1-methyl-3-nitro-1-nitrosoguanidine and BP in strain TA 100 . In the BP-induced forestomach tumor model, all four carotenoids showed a similar significant anticarcinogenic effect . Dietary administration of palm oil showed a dose-dependent antitumor activity in the animals . Our results show that the intrinsic antimutagenic and anticarcinogenic properties of the carotenoids are not significantly influenced by their conversion to vitamin A. IARC Sci Publ, 1992, (116), 323 - 52 Chemicals classified by IARC: their potency in tests for carcinogenicity in rodents and their genotoxicity and acute toxicity; McGregor DB; Chemicals classified by the IARC to its groups 1, 2A, 2B and 3 were examined in an attempt to identify characteristics of their behaviour in experimental studies of carcinogenicity, genotoxicity and acute mammalian toxicity that correlate with those categories . Only those agents for which information on carcinogenic potency was available were studied . In both mice and rats, more chemicals were potent carcinogens if they had been categorized in Group 1 (human carcinogens) than if they had been put into one of the other categories . Not surprisingly, there was a weak association between carcinogenic potency and acute toxicity . Mice were especially sensitive to tumour induction by halides; the lower sensitivity of rats to any carcinogenic effect of halides could be due in part to their higher systemic toxicity in this species: a reduced differential of toxic and carcinogenic doses decreases the dose window in which carcinogenic effects may be demonstrated . It was notable that the human carcinogens were active in those genotoxicity tests with higher specificity for identifying rodent carcinogens . Predictive assays for carcinogenicity that were considered to be highly specific were tests for cytogenetic effects in vivo, unscheduled DNA synthesis in hepatocytes, mutation in any of the five commonly used strains of Salmonella typhimurium and mutation at the hprt locus in mammalian cells . None of the relationships was strong enough to form the basis of a simple categorization, but they could serve to alert investigators to chemicals of special toxicological interest and importance. Ophthalmic Res, 1992, 24(3), 162 - 8 Retino-choroidal changes in endotoxin-induced uveitis in the rat; Ruiz-Moreno JM et al.; A single injection of 100 micrograms of lipopolysaccharide from Salmonella typhimurium in the foot pads of Lewis rats induced acute inflammation of the eye . Clinically, the disease started as early as 0.5 h and peaked 18 h after the inoculation . The aqueous protein concentration was increased after the inoculation . Histopathologically, cellular infiltrates and proteinaceous exudates were observed in the anterior segment (anterior chamber, iris and ciliary body) . In addition to those changes described in previous reports, the examination of the posterior segment showed retinal vasculitis, hemorrhagic exudates, focal destruction of photoreceptor cells and choroidal infiltration. Microbiol Immunol, 1992, 36(4), 369 - 80 Bactericidal activities of rat defensins and synthetic rabbit defensins on Staphylococci, Klebsiella pneumoniae (Chedid, 277, and 8N3), Pseudomonas aeruginosa (mucoid and nonmucoid strains), Salmonella typhimurium (Ra, Rc, Rd, and Re of LPS mutants) and Escherichia coli; Kohashi O et al.; Rat defensins were purified and tested for in vitro bactericidal assay against gram-positive and gram-negative bacteria . Staphylococcus aureus (209P, Cowan I, Smith diffuse and Smith compact) were resistant to defensins, whereas Staphylococcus epidermidis, Staphylococcus saprophyticus, Micrococcus lysodeikticus and Bacillus subtilis were less sensitive . Gram-negative bacteria, such as Pseudomonas aeruginosa (mucoid and K) and Klebsiella pneumoniae (Chedid, 277, and 8N3 which were heavily capsulated, moderately capsulated and noncapsulated, respectively) were all very sensitive to defensins and killed within 20 min . Escherichia coli was moderately sensitive and the rough mutants of lipopolysaccharide (LPS) of Salmonella typhimurium LT2, such as Ra, Rc, Rd, and Re were equally sensitive to defensins, being killed within 40 min . Lysozyme did not show any bactericidal activity except against M . lysodeikticus and B . subtilis, whereas it enhanced the bactericidal activity of defensins against P . aeruginosa, E . coli, and K . pneumoniae and suppressed the killing activity of defensins against S . typhimurium and S . aureus . With regard to the three synthetic rabbit defensins, NP1, NP4, and NP5, NP1 showed strong bactericidal activity against K . pneumoniae 277, comparable to that of rat defensins . Neither NP4 nor NP5 showed any bactericidal activity, while NP5 rather enhanced the bactericidal activity of NP1 against K . pneumoniae 277. Microbiol Immunol, 1992, 36(4), 339 - 50 Molecular cloning and nucleotide sequencing of a novel aminoglycoside 6'-N-acetyltransferase gene from an R-plasmid of Salmonella typhimurium S24 isolated in Taiwan; Peng CF et al.; A conjugative aminoglycoside resistance plasmid pST2 has been isolated from Escherichia coli K-12 14R525, which was mated with a clinical isolate of Salmonella typhimurium S24 . A novel resistance gene of aminoglycoside 6'-N-acetyltransferase{AAC(6')} was cloned from plasmid pST2 on a 1,393 kilobase (kb) of SphI-SalI fragment into vector pACYC184 and pUC18 . This novel AAC(6') gene in plasmid pST2 acetylated kanamycin, amikacin, dibekacin, tobramycin, gentamicin, netilmicin, and sisomicin . The complete nucleotide sequence of the novel AAC(6') gene and its neighboring sequences were also determined . Minicell experiments detected only one protein of 24.7 kilodaltons (kDa) translated from an open reading frame of the 618 base pairs (bp) gene. Food Addit Contam, 1992 Jan-Feb, 9(1), 29 - 37 N-nitrosamine and mutagenicity formation in Chinese salted fish after digestion; Weng YM et al.; Salted and dried fish (Nemipterus virgatus), acquired from Hong Kong, was treated with 0.43-110 mM nitrite during in vitro digestion using gastric enzymes and the volatile N-nitrosamine content and mutagenicity on Salmonella typhimurium TA100 assayed without concentration . N-Nitrosodimethylamine (NDMA; the only nitrosamine detected) formation was second order in nitrite concentration . When 10 g of fish was treated with 6.96 mM nitrite, 394 nM NDMA was formed . Thiocyanate was catalytic for NDMA formation at nitrite concentration greater than 0.87 mM and when the ratio of thiocyanate to nitrite was greater than 1 . Approximately a 50% inhibition in NDMA formation by ascorbic acid was seen when the ratio of ascorbate to nitrite was approximately 2 or greater and the nitrite concentration was 1.74 mM . Mutagenicity increased with increasing nitrite concentration but the addition of thiocyanate did not increase mutagenicity over nitrite alone . Ascorbate increased mutagenicity even though NDMA formation was inhibited . Even at nitrite concentrations greater than 100-fold higher than expected in vivo, there was insufficient NDMA formed to account for the observed mutagenicity . These data do not exclude the possibility that the observed mutagenicity was due to non-volatile N-nitroso compounds, however, this possibility seems unlikely given the effects of ascorbate and thiocyanate which would be expected to inhibit and enhance non-volatile N-nitroso compound formation. Environ Mol Mutagen, 1992, 20(3), 211 - 7 The role of glutathione in the bacterial mutagenicity of vapour phase dichloromethane; Dillon D et al.; Dichloromethane (DCM) vapour by inhalation is carcinogenic to rodents and is an in vivo rodent cell clastogen and a bacterial mutagen . It has been suggested that the bacterial mutagenicity of DCM is mediated by glutathione (GSH) conjugation . The involvement of endogenous and exogenous GSH in the conversion of DCM to a bacterial mutagen has been studied in a vapour phase protocol using wild-type and GSH-deficient (NG54; gsh) Salmonella typhimurium TA100 strains in the presence and absence of various rat liver fractions . The effect of the duration of exposure was also investigated in these Salmonella strains and in E . coli WP2 uvrA pKM101 . Dose- and time-related increases in revertants occurred with all metabolic activation systems used (without exogenous metabolic activation; with Aroclor-induced rat liver S9, microsomes, or cytosol fractions), with minor quantitative differences among the 3 strains . Mutagenicity was marginally highest in the presence of cytosol at the highest DCM concentrations . Strain NG54 gsh, which contains approximately 25% of the TA100 level of GSH/microgram protein, was slightly less responsive to DCM-induced mutagenicity than TA100 . Addition of 0.33 mumoles/plate of GSH had little effect on the mutagenic responses of TA100 or NG54 in the presence or absence of S9 . In these 2 strains, exogenous S9 produced small increases in mutagenicity at the highest concentrations of DCM (2 and 4% v/v) . These results suggest that if an interaction between DCM and GSH is required for the activation of DCM to a bacterial mutagen, it occurs at low levels of endogenous GSH and is not significantly affected by GSH supplementation. Environ Mol Mutagen, 1992, 20(3), 188 - 98 Evaluation of the mutagenicity of an N-nitroso contaminant of the sunscreen Padimate O: N-nitroso-N-methyl-p-aminobenzoic acid, 2-ethylhexyl ester (NPABAO); Dunkel VC et al.; The nitrosamine contaminant, N-nitroso-N-methyl-p-aminobenzoic acid, 2-ethylhexyl ester (NPABAO), of the major sunscreen ingredient Padimate O (4-N,N'-dimethylamino-benzoic acid, 2-ethylhexyl ester) was synthesized and tested for mutagenicity in the Salmonella typhimurium and mouse lymphoma L5178Y TK +/- assays . In contrast to the previously reported positive responses in S . typhimurium tester strains TA100 and TA1535 {Loeppky et al., 1991}, there were no increases in the number of revertants with strains TA98, TA100, TA1535, and TA1538 in either the Salmonella plate incorporation {Ames et al., 1975} or preincubation {Yahagi et al., 1977} assays . Additional testing with Salmonella, following the modified preincubation procedure {Rogan, 1990} that gave the initial positive response, was also negative . Data from the mouse lymphoma assays were also uniformly negative . During synthesis of NPABAO, small amounts of 4-N,N'-dimethylamino-3-nitrobenzoic acid, 2-ethylhexyl ester (DMANBAO) can be formed . To determine whether the reported positive mutagenicity response of NPABAO could be the result of trace amounts of DMANBAO in the NPABAO, that compound was also synthesized and tested for mutagenicity with Salmonella . Positive responses were obtained with tester strains TA98 and TA 1538 but not with TA100 and TA1535, indicating that DMANBAO was not responsible for the increase in revertants originally reported. Mutat Res, 1992, 280(3), 161 - 8 Effects of supercypermethrin, a synthetic developmental pyrethroid, on four biological test systems; Miadokova E et al.; The genotoxic potential of the insecticide supercypermethrin, a second-generation pyrethroid, was studied on four different test systems . It was non-mutagenic to Salmonella typhimurium strains TA1535, TA100, TA1538, TA98 and TA97 in the presence and absence of S9 mixture . It induced gene conversion at the tryptophan locus and induced point mutations at the isoleucine locus in Saccharomyces cerevisiae cells . A slight increase in the frequency of aberrant anaphases and telophases in root tips of Hordeum vulgare and Vicia faba was observed, but no genotoxic effects were detected in Drosophila melanogaster. Environ Mol Mutagen, 1992, 20(1), 61 - 72 Comparison of acyltransferase-mediated mutagenicity and nucleic acid binding of N-acetoxy-4-acetylaminobiphenyl by hepatic and bladder microsomes from rats and dogs; Swaminathan S et al.; Acyltransferase-mediated mutagenic and metabolic activation of N-acetoxy-4-acetylaminobiphenyl (N-OAc-AABP) by hepatic tissues of rats and dogs were compared . N-OAc-AABP was mutagenic in Salmonella typhimurium TA98 even in the absence of exogenous enzyme(s) . However, supplementation with hepatic microsomes from dogs showed a dose-dependent increase in mutagenicity of N-OAc-AABP, whereas under the same conditions, rat microsomes were inactive . Incubation of liver microsomes with RNA showed that 46.4 and 11.2 nmole of {3H}N-OAc-AABP were bound/mg RNA/mg protein with dogs and rats, respectively . The hepatic microsome-mediated binding and mutagenicities of N-OAc-AABP were blocked by paraoxon, suggesting the involvement of deacetylase(s) in the activation process . Analyses of the in vitro incubates of N-OAc-AABP with rat and dog liver microsomes revealed the O-deacetylation product N-hydroxy-4-acetylaminobiphenyl (N-OH-AABP) as the major metabolite . The ratios of O-deacetylation of N-O{14C}Ac-AABP versus N-deacetylation of N-OAc-{14C}AABP for hepatic microsomes from dogs and rats were 2.9 and 7.2, respectively . The O- and N-deacetylases are also distributed in bladder tissues and their activities in comparison to the hepatic tissues were lower and amounted to 14.2 and 5.0 nmoles (O/N-deacetylation ratio 2.8) for dogs and 14.8 and 1.7 nmoles per mg protein per min (O/N-ratio of 8.7) for rats . The microsomes from bladder tissues also catalyzed the binding of {3H}N-OAc-AABP to RNA and enhanced its mutagenic response in TA98, both of which were blocked by paraoxon . The occurrence of deacetylase(s) in the target tissues of the bladder carcinogen 4-acetylaminobiphenyl (AABP) suggests that metabolic activation of some of the proximate metabolites could occur within these target organs . Furthermore, since the O-deacetylation product N-OH-AABP is relatively innocuous compared to the N-deacetylation product N-acetoxy-4-aminobiphenyl, these results imply that the refractiveness of rats for 4-aminobiphenyl or AABP-induced bladder carcinogenesis might in part be associated with the higher ratios of microsomal O/N-deacetylase activities . Thus susceptibility to arylamine or arylacetamide-induced liver and bladder carcinogenesis might be influenced by the microsomal deacetylases. Vaccine, 1992, 10(6), 405 - 11 Synthetic recombinant vaccine expressing influenza haemagglutinin epitope in Salmonella flagellin leads to partial protection in mice; McEwen J et al.; The influenza virus haemagglutinin epitope 91-108, which is a conserved amino acid sequence in all type A H3 strains, was expressed in Salmonella flagellin, to evaluate its potential as a vaccine . For that purpose, a synthetic oligonucleotide comprising 54 bases coding for the corresponding sequence was inserted into the plasmid pLS408 and transformed into Escherichia coli JM101 . Colonies containing the recombinant plasmid were used to transform Salmonella typhimurium LB5000 and were then transduced to a flagellin negative 'live vaccine' aroA mutant of Salmonella dublin . Rabbits immunized either with the live recombinant S . dublin or with the flagellin isolated from it, showed significant levels of IgG response against the synthetic peptide 91-108 as well as against the intact A/Texas/77 influenza virus . Mice immunized with the same preparations developed influenza-specific IgG antibodies in the blood and secreted IgA antibodies in their lungs . Furthermore, these mice showed about 50% protection against challenge infection with the virus . The most successful results were achieved by intranasal immunization with the isolated recombinant flagellin, when employed without the aid of adjuvant. Mutat Res, 1992 Jan, 281(1), 55 - 61 Genotoxicity and cell proliferative activity of a nitrosated Oroxylum indicum Vent fraction in the pyloric mucosa of rat stomach; Tepsuwan A et al.; In vivo genotoxic activity and cell proliferative activity were examined in the stomach mucosa of male F344 rats by in vivo short-term methods after oral administration of a nitrosated Oroxylum indicum Vent (OiV) fraction, which had been found to be mutagenic without S9 mix to Salmonella typhimurium TA98 and TA100 . Administration of the nitrosated OiV fraction at doses of 1 and 2 g/kg body weight induced dose-dependent DNA single-strand scission (p less than 0.02), determined by the alkaline elution method, in the stomach pyloric mucosa 2 h after its administration: a dose of 2 g/kg body weight induced an 18-fold increase in the DNA elution rate constant . Administration of the nitrosated OiV fraction at doses of 0.7-2.8 g/kg body weight also induced dose-dependent increases, up to 11-fold (p less than 0.05), in replicative DNA synthesis in the stomach pyloric mucosa 16 h after its administration . Moreover administration of the nitrosated OiV fraction at doses of 0.25-2.0 g/kg body weight induced dose-dependent increases, up to 100-fold, in ornithine decarboxylase activity in the stomach pyloric mucosa with a maximum 4 h after its administration . These results demonstrate that the nitrosated OiV fraction has genotoxic and cell proliferative activity in the pyloric mucosa of rat stomach in vivo. J Bacteriol, 1992 Jan, 174(1), 336 - 41 Characterization of lipopolysaccharide fractions and their interactions with cells and model membranes; Yeh HY et al.; The role of the length of the O-antigen polysaccharide side chain of bacterial lipopolysaccharide (LPS) in biological and model membrane systems was investigated . LPS from Salmonella typhimurium ATCC 14028 was chromatographed on a Sephadex G-200 column in the presence of sodium deoxycholate and separated into three fractions on the basis of molecular size . Sodium dodecyl sulfate-polyacrylamide gel electrophoresis, Western blot (immunoblot), and chemical analyses indicated that these fractions differed from each other primarily in the number of repeating units in the O-antigen polysaccharide side chain . In a biological system fractions 2 and 3 had the same effects to induce mitogenesis in murine lymphocytes, but fraction 1 was less effective than the other two fractions . In a model membrane system, LPS induced changes in small unilamellar vesicles (SUVs) which were measured by changes in the behavior of a fluorescent probe, 1,6-diphenylhexa-1,3,5-triene (DPH), and interaction of increasing amounts of all LPS fractions with SUVs gradually increased DPH anisotropy . Fractions 2 and 3 had similar effects on the SUVs as detected by changes in DPH anisotropy, while fraction 1 had almost twice as much activity as the other two fractions . These results suggest that the polysaccharide side chain of LPS may modulate the ability of biologically active lipid A to interact with cells and model membranes . In addition, factors other than changes in membrane fluidity may play a role in mediating LPS-induced cell activation. Mutat Res, 1992 Jan, 265(1), 61 - 73 Structural requirements for the induction of the SOS repair in bacteria by nitrated polycyclic aromatic hydrocarbons and related chemicals; Mersch-Sundermann V et al.; The CASE (computer-automated structure evaluation) methodology was used to investigate the structural basis of the SOS-inducing activity of 56 nitrated polycyclic aromatic hydrocarbons (nitroarenes, nPAH) and the unsubstituted parent PAH molecules . Based upon the presence and/or absence of structural features, CASE identified 5 activating (biophores) and 4 inactivating (biophobes) fragments responsible for the SOS-inducing activity . Based upon these fragments, CASE correctly calculated the genotoxicity of 94.6% of the molecules in the training set (sensitivity = 0.85, specificity = 1.0) . Disregarding the questionable experimental results of the unexpected very weak direct-acting activity of the unsubstituted benzo{a}pyrene, dibenzo{a,h}anthracene and 7,12-dimethylbenz{a}anthracene, the concordance of the prediction was 100%, i.e., sensitivity = 1.0, specificity = 1.0 . Additionally, the quantitative analysis of the SOS-inducing potency showed a good correlation between the experimental and predicted results . The present analyses indicate an identity in the structural determinants responsible for SOS induction in E . coli PQ37 (SOS chromotest) and mutagenicity in Salmonella typhimurium. Mutat Res, 1992 Jan-Mar, 276(1-2), 93 - 100 Results of a comparative study on the Salmonella pre-incubation and plate incorporation assays using test samples from the IPCS collaborative study; Goto S et al.; Three complex mixtures (air particles, diesel particles and a coal tar fraction) and two pure compounds (benzo{a}pyrene and 1-nitropyrene) were tested in both the pre-incubation and the plate incorporation assay employing Salmonella typhimurium TA98 and TA100 . Each experiment was conducted independently 2 or 4 times in duplicate in the presence and absence of metabolic activation . The mutagenic activities were calculated by least squares linear regression from the slope of the linear portion of each dose-response curve . Although slightly higher mutagenic activity was observed in the pre-incubation assay for the two pure compounds and with the plate incorporation assay for the diesel particulate sample, the overall data from both assays gave similar values and good correlations in TA100 and TA98 . The results indicate that the pre-incubation assay could be used for these samples instead of the plate incorporation assay. Mutat Res, 1992 Jan-Mar, 276(1-2), 3 - 9 Design and implementation of a collaborative study of the mutagenicity of complex mixtures in Salmonella typhimurium; Lewtas J et al.; In 1987, the International Programme on Chemical Safety (IPCS) in collaboration with the U.S . Environmental Protection Agency (U.S . EPA) and the U.S . National Institute of Standards and Technology (U.S . NIST) initiated an international collaborative study of the mutagenicity of complex environmental mixtures in the Ames Salmonella typhimurium mutation assay . The objectives of this study were: (1) to estimate the inter- and intra-laboratory variability associated with the extraction of mixtures for bioassay, (2) to estimate the inter- and intra-laboratory variability associated with the Salmonella typhimurium bioassay when applied to complex mixtures, and (3) to determine whether standard reference complex mixtures would be useful in mutagenicity studies and to evaluate whether reference or certified mutagenicity values determined from this collaborative study should be reported . The complex mixtures used in this study were selected from standard reference materials (SRMs) which had previously been issued by the U.S . NIST as SRM 1597 (coal tar), SRM 1649 (diesel particulate matter) and SRM 1650 (urban air particulate matter) with certified values for polycyclic aromatic hydrocarbons . These SRM complex mixtures are available to scientists as reference standards for analytical chemistry research and are under consideration as SRMs for mutagenicity studies of complex environmental mixtures . This paper briefly describes the final study design, protocol, selection of the complex mixtures, and implementation of this international study. Mutat Res, 1992 Jan-Mar, 276(1-2), 101 - 15 Mutagenicity and chemical analysis of sequential organic extracts of airborne particulates; Savard S et al.; To obtain insight into the identity of chemicals associated with the mutagenicity of United States National Institute of Standards and Technology (NIST) Standard Reference Materials SRM 1649 (urban dust) and SRM 1650 (diesel particulate), parallel mutagenicity tests and chemical analyses were performed on dichloromethane and sequential organic extracts of these samples . SRM 1649 and 1650 were sequentially extracted with five organic solvents of increasing polarity, in order to partition mutagenic components into discrete fractions . The solvents (with associated polarity index) were as follows: (1) hexane (0.0); (2) hexane:diethyl ether 9:1 (0.29); (3) hexane:diethyl ether 1:1 (1.45); (4) diethyl ether (2.9); (5) methanol (6.6) . 0.9270 g of SRM 1649, and 0.0510 g of SRM 1650 were each extracted three times with 8 ml of each of the solvents, the three aliquots were pooled, and analysed for target organics or solvent-exchanged into DMSO for mutagenicity testing in Salmonella typhimurium strains TA98 and TA100 . The dichloromethane extracts of SRM 1649 and SRM 1650 contained direct-acting mutagens in Salmonella strains TA98 and TA100; SRM 1650 was significantly more potent than SRM 1649 in either strain . Addition of S9 caused a large decrease in mutagenicity of each extract, although SRM 1650 remained more potent . An interesting pattern of mutagenicity was observed for the sequential extracts of SRM 1649 and SRM 1650: the mutagenic potency of SRM 1649 extracts increased with increasing polarity of the extraction solvent while the response of the SRM 1650 extracts was the opposite . This suggests that the direct-acting mutagens in SRM 1650 are unlike those in SRM 1649 . The response, though diminished, was largely unchanged when S9 was included in the test mixture . Chemical analyses on the various extracts were performed using a Hewlett-Packard model 5890 gas chromatograph equipped with a model 5970B mass selective detector (GC-MSD), and a 0.3 microns film thickness cross-linked methyl silicone capillary column (HP 1909A-101) . Selected ion monitoring (SIM) methods were used to analyze for 105 target compounds including PAHs and nitro-PAHs . Chemical analysis of the dichloromethane extracts of SRM 1649 and SRM 1650 identified three main classes of compounds: polyaromatic hydrocarbons (PAH), nitro-polyaromatic hydrocarbons (NO2-PAHs) and heterocyclics . The concentration of target compounds and the proportion of nitro-PAHs and heterocyclic compounds were considerably greater in SRM 1650 than in SRM 1649, consistent with the observed differences in their mutagenic potency . However, the different responses of the dichloromethane extracts in TA98 and TA100 suggest the presence of different (unidentified) compounds.(ABSTRACT TRUNCATED AT 400 WORDS) Microbiol Immunol, 1992, 36(6), 593 - 602 Type 1 pili enhance the invasion of Salmonella braenderup and Salmonella typhimurium to HeLa cells; Horiuchi S et al.; The relationship between type 1 pili-associated adhesion and invasion to HeLa cells by Salmonella braenderup and S . typhimurium was studied . When the clinical isolates of these strains were grown in L-broth, they showed both type 1 pili formation and mannose-sensitive adhesion to HeLa cells . On the other hand, the type 1 pili-defective mutants, which were obtained either by repeated subcultures on L-agar plates or by the transposon Tn1-insertion mutagenesis of the S . braenderup and S . typhimurium strains, concomitantly lost mannose-sensitive adhesion to HeLa cells . When the HeLa cells were incubated with Salmonella, the type 1 piliated strains invaded the HeLa cells with much higher infection rate than did the type 1 pili-defective strains . The invasion of type 1 piliated strains to HeLa cells was markedly inhibited in the presence of D-mannose . The infectivity of the strain, which lost type 1 pili but still had mannose-resistant adhesion, was slightly higher than that of the strains defective in both mannose-sensitive and mannose-resistant adhesion . These results suggested that type 1 pili have a role in enhancing the invasion of S . braenderup and S . typhimurium to HeLa cells. Acta Virol, 1992 Jan, 36(1), 25 - 31 Dynamics of non-specific antibacterial activity of the peritoneal cells of mice induced with Coxiella burnetii antigen; Tokarevich NK et al.; It was found that primary immunization with Coxiella burnetii antigen increased mouse resistance to Salmonella typhimurium infection as evidenced by acceleration of bacterial elimination from the peritoneal cavity and a decrease in lethality of experimental animals . The existence of two rises of bactericidal activity of mouse peritoneal cells was ascertained: the "early" on days 1 and 2, and the "late" on day 14 after C . burnetii administration . The first rise was accompanied by some increase in the number of peritoneal cells as well as by some change of their qualitative representation . The second increase of antibacterial activity was detected during the pronounced cellular and humoral immune responses to C . burnetii. J Med, 1992, 23(5), 327 - 38 Effects of tetanus toxin, Salmonella typhimurium porin, and bacterial lipopolysaccharide on platelet aggregation; Matera C et al.; Endotoxins may interfere with platelet aggregation by interacting with the platelet membrane . The aim of this study was to evaluate the effects of tetanus toxin, Salmonella typhimurium porin, and bacterial lipopolysaccharide (LPS) on platelet aggregation induced by ADP and thrombin in vitro . Spontaneous platelet aggregation and platelet aggregation induced by ADP and thrombin were measured . Our results show that Salmonella typhimurium porin and bacterial LPS enhanced human and rabbit platelet aggregation induced by ADP and thrombin . Tetanus toxin did not affect platelet aggregation. Vaccine, 1992, 10(12), 811 - 3 Active protection of mice against Salmonella typhi by immunization with strain-specific porins; Isibasi A et al.; NIH mice were immunized with between 2.5 and 30 micrograms of two highly purified porins, 34 kDa and 36 kDa, isolated from the virulent strain Salmonella typhi 9,12, Vi:d . Of mice immunized with 10 micrograms of porins, 90% were protected against a challenge with up to 500 LD50 (50% lethal doses) of S . typhi 9,12,Vi:d and only 30% protection was observed in mice immunized with the same dose of porins but challenged with the heterologous strain Salmonella typhimurium . These results demonstrate the utility of porins for the induction of a protective status against S . typhi in mice. Environ Mol Mutagen, 1992, 20(4), 289 - 96 Certain tryptophan photoproducts are inhibitors of cytochrome P450-dependent mutagenicity; Rannug U et al.; Two photoproducts, derived from UV-irradiation of the amino acid L-tryptophan and with high Ah (TCDD) receptor binding affinity, were tested for genotoxic and antimutagenic effects . The two indolo{3,2-b}carbazole derivatives, with the molecular weights of 284 and 312, respectively, were tested in Saccharomyces cerevisiae strain D7 for mitotic gene conversion and reverse mutation and in strain RS112 for sister chromatid conversion and gene conversion . No significant (P > 0.05) genotoxic effects were found in strain D7, while strain RS112 showed a small but significant increase in the frequency of sister chromatid conversions . In Chinese hamster ovary (CHO) cells the two compounds induced a statistically significant but less than twofold increase in the frequency of sister chromatid exchanges (SCE) . No mutations were detected when the compounds were tested in Salmonella typhimurium strains TA98 and TA100 . However, both 284 and 312 acted as antimutagens on strain TA100 + S9 in the presence of benzo(a)pyrene . The decrease in mutagenicity by the most potent compound 284 was 20 revertants/nmol . This effect could be explained by an inhibitory effect on the cytochrome P450-dependent ethoxyresorufin O-deethylase (EROD) activity as seen in rat hepatocytes . The two compounds were also tested with hamster cells expressing rat cytochrome P-450IA1 . The results support the conclusion that this cytochrome P-450 isozyme is inhibited by the tryptophan photoproducts . Similar results were also seen with two other high affinity Ah receptor ligands the quinazolinocarboline alkaloids rutaecarpine and dehydrorutaecarpine. Microbiol Immunol, 1992, 36(3), 269 - 78 The comparison of cell-mediated immunity induced by immunization with porin, viable cells and killed cells of Salmonella typhimurium; Matsui K et al.; A marked level of cell-mediated immunity (CMI) to Salmonella typhimurium-infection in mice, as determined by acquired resistance, delayed-type hypersensitivity, interleukin-2 production and interferon-gamma production, was induced by immunization with porin or viable cells but not with killed cells of S . typhimurium LT2 . When the up-regulation of immune system to each immunogen was studied by comparing increases of Ia-bearing macrophages, the immunization with porin or viable cells, but not killed cells, could stimulate the immune system for more than 14 days . Interleukin-1 (IL-1) production of macrophages to each immunogen was also examined; the result showed that immunization with porin or viable cells could induce a notable level of IL-1 production, while killed cells could not . However, when the abilities to induce these immune responses were compared between UV-killed and heat-killed cells, UV-killed cells were superior to heat-killed cells . These results suggested that the ineffectiveness of immunogen that lacked CMI-inducing ability might be ascribed to the denaturation of antigen and the insufficient inductions of Ia-bearing macrophages and IL-1 production. Environ Mol Mutagen, 1992, 19(3), 185 - 94 Mutations in topA interfere with the inducible expression of DNA damage response loci in Salmonella typhimurium; Smith CM et al.; Strains of Salmonella typhimurium deficient in topoisomerase I activity (topA mutants) are UV sensitive and non-mutable (Overbye and Margolin: J Bacteriol 146:170-178, 1981) . Using lac-operon fusions to DNA damage inducible (din) loci we investigated whether these observations could be explained by an inability of topA strains to efficiently induce DNA damage responses . Mitomycin C (MMC)-induced expression of lac-operon fusions to uvrB and to a second SOS locus, din-9, was largely eliminated in topA bacteria . The inducible expression of several other din-fusions was also diminished . This inducibility defect was mimicked by growth of din-9 topA+ bacteria in media of high osmolarity, a condition that leads to increased DNA supercoiling . Inhibitors of DNA gyrase efficiently induced din-9 in topA bacteria . Together, these results suggest that the topA effect on din expression may be mediated at the level of DNA supercoiling . The sensitivities of a number of din-fusions to topA paralleled the degree to which they were repressed by excess LexA, suggesting that mutations in topA might influence LexA-operator interactions and/or increase lexA expression. Environ Mol Mutagen, 1992, 19(2), 156 - 60 Nitrobenzo{a}pyrene-induced DNA amplification in SV40-transformed Chinese hamster embryo cells; Neft RE et al.; Nitrobenzo{a}pyrenes (NBaPs) are ubiquitous environmental pollutants that produce mutations in Salmonella typhimurium and Chinese hamster ovary cells . In this study, 1-, 3-, and 6-NBaP induced amplification of SV40 DNA sequences in an SV40-transformed Chinese hamster embryo cell line which is sensitive to DNA amplification by various known carcinogens . Of the three isomers, 3-NBaP produced the highest level of gene amplification, which was 4.8 relative to untreated controls at a dose of 5 micrograms/ml . Considering the relationship between gene amplification and tumorigenesis, it seems prudent to carry out a more exhaustive analysis of the carcinogenic potential of these agents. J Bacteriol, 1992 Jan, 174(1), 245 - 53 A method for constructing single-copy lac fusions in Salmonella typhimurium and its application to the hemA-prfA operon; Elliott T; This report describes a set of Escherichia coli and Salmonella typhimurium strains that permits the reversible transfer of lac fusions between a plasmid and either bacterial chromosome . The system relies on homologous recombination in an E . coli recD host for transfer from plasmid to chromosome . This E . coli strain carries the S . typhimurium put operon inserted into trp, and the resulting fusions are of the form trp::put::{Kanr-X-lac}, where X is the promoter or gene fragment under study . The put homology flanks the lac fusion segment, so that fusions can be transduced into S . typhimurium, replacing the resident put operon . Subsequent transduction into an S . typhimurium strain with a large chromosomal deletion covering put allows selection for recombinants that inherit the fusion on a plasmid . A transposable version of the put operon was constructed and used to direct lac fusions to novel locations, including the F plasmid and the ara locus . Transductional crosses between strains with fusions bearing different segments of the hemA-prfA operon were used to determine the contribution of the hemA promoter region to expression of the prfA gene and other genes downstream of hemA in S . typhimurium. Arch Biochem Biophys, 1992 Jan, 292(1), 179 - 89 Reaction of the nucleotide analogue 2-{(4-bromo-2,3-dioxobutyl)thio}adenosine 2',5'-bisphosphate at the coenzyme site of wild-type and mutant NADP(+)-specific glutamate dehydrogenases from Salmonella typhimurium; Haeffner-Gormley L et al.; Wild-type glutamate dehydrogenase (EC 1.4.1.4) from Salmonella typhimurium reacts at 25 degrees C in 0.1 M phosphate buffer, pH 7, with the nucleotide analogue 2-{(4-bromo-2,3-dioxobutyl)thio}-adenosine 2',5'-bisphosphate (2-BDB-TA 2',5'-DP) to give 78% inactivation . Protection against inactivation was achieved with NADPH, indicating that modification occurred in the region of the coenzyme binding site . After reaction of the enzyme with 2-BDB-TA 2',5'-DP, the dioxo moiety of the bound reagent was reduced with {3H}NaBH4 . The radioactive peptide which corresponds to the sequence Leu282-Cys283-Glu284-Ile285-Lys286 was isolated by HPLC from tryptic digests of inactive modified enzyme but was absent in digests of active enzyme modified in the presence of NADPH . Mutant enzyme E284Q was 64% inactived by 2-BDB-TA 2',5'-DP and modification of the corresponding Leu282-Lys286 peptide was found, while neither mutant enzyme C283I nor C283I:E284Q was inactivated by the nucleotide analogue and no corresponding radioactive peptides were found . These results show that cysteine-283 is the target of the reagent and is located near the coenzyme binding site . The nucleotide analogue 2-{(4-bromo-2,3-dioxobutyl)thio}-1,N6-ethenoadenosine 2',5'-bisphosphate (2-BDB-T epsilon A 2',5'-DP) has also been shown to react with cysteine-283 (L . Haeffner-Gormley et al., 1991, J . Biol . Chem . 266, 5388-5394) . However, the predominant form of the Leu282-Lys286 peptide after reaction with 2-BDB-TA 2',5'-DP contained only 0.17 mol tritium/mol leucine, whereas the 2-BDB-T epsilon A 2',5'-DP-modified peptide contained 1.80 mol tritium/mol leucine; these results indicate that the reaction product of 2-BDB-T epsilon A 2',5'-DP retains two reducible carbonyl groups while these are not available in the product of 2-BDB-TA 2',5'-DP . It is suggested that cysteine-283 reacts primarily at a carbonyl group of 2-BDB-TA 2',5'-DP to form a thiohemiacetal derivative, while it reacts at the methylene group of 2-BDB-T epsilon A 2',5'-DP with displacement of bromide . Both nucleotide analogues also yielded, in small amount, a crosslinked peptide containing the sequences 282-286 and 299-333, indicating proximity between these regions in the native structure. Int J Tissue React, 1992, 14(5), 211 - 8 Butylated hydroxyanisole produces both mutagenic and desmutagenic derivatives under gastric conditions; Kanazawa K et al.; Dietary butylated hydroxyanisole (BHA) has been known to have inconsistent functions on carcinogenesis, both prevention and initiation . We assumed that both functions of BHA were introduced by the derivatives formed after the reaction with gastric components such as nitrite in the stomach . We then identified the derivatives produced by incubating BHA with sodium nitrite at pH 2.0 or pH 5.0 . Eight derivatives were detected; 2-tert.-butyl-p-quinone (BQ), 3,3'-di-tert.-butyl-biphenyldiquinone-(2,5,2',5') (BBDQ), 2,6-di-tert.-butyl-8-hydroxy-dibenzofuran-1,4-quinone (BHDQ), 6-nitro-BHA, 2,2'-dihydroxy-3,3'-di-tert.-butyl-5,5'-dimethoxy-biphenyl (di-BHA), an oxidized product of di-BHA, and two unstable reaction intermediates . BQ was a major final product at pH 2.0, but not at pH 5.0 . 6-Nitro-BHA and the oxidized products of di-BHA were also the final products . BBDQ was formed from di-BHA and easily converted to BHDQ . Their mutagenicity and desmutagenicity were assayed using Salmonella typhimurium strains . BQ and BBDQ were the mutagens of base-substitution type, BHDQ was the potent desmutagen against a mutagenicity of Trp-P-2, and the others had neither of the two activities . Thus, BHA was found to produce both the mutagen and desmutagen under the gastric conditions . BQ has been previously reported to be easily detoxified by glutathione, and BHA itself is well known to prevent carcinogenesis . In the assessment of dietary BHA on carcinogenesis, since one of the mutagens from BHA is easily detoxified in our bodies and another is converted to a desmutagen, BHA appears to be one of the favourable chemicals for us. J Am Vet Med Assoc, 1991 Dec 15, 199(12), 1757 - 9 Salmonella typhimurium abscess as a postoperative complication in a horse with colic; Blikslager AT et al.; An 11-year-old, 430-kg fox-trotter stallion was referred for evaluation of colic . A right-sided inguinal hernia was diagnosed . At exploratory laparotomy, the ileum was found to be herniated through the right inguinal canal . Compromised small intestine was resected, jejunocecal anastomosis was performed, and the horse was castrated . Three days after surgery, the stallion would not bear weight on the left hind limb . The musculature of the left thigh region became swollen . Aspiration of the left thigh region yielded serosanguineous fluid from which Salmonella typhimurium was isolated . Ultrasonography of the left thigh revealed multiple hypoechoic areas suggestive of abscess . The left medial thigh region was surgically incised, and a large abscess was drained . Bacteriologic culture of feces yielded S typhimurium . The owner elected to have the horse euthanatized. Proc Natl Acad Sci U S A, 1991 Dec 15, 88(24), 11470 - 4 Intracellular replication is essential for the virulence of