Toxicol Lett, 1987 May, 36(3), 281 - 7 Methemoglobinogenic potential of primaquine and its mutagenicity in the Ames test; Marrs TC et al.; Single doses of primaquine did not produce methemoglobinemia in beagle bitches . Repeated daily administration for 12 days produced a gradually rising level of methemoglobin over that time period, unaccompanied by depletion of erythrocytic reduced glutathione . Primaquine was mutagenic in the Ames test in Salmonella typhimurium strain TA 1537, with or without S9, using a liquid preincubation assay . Primaquine was non-mutagenic in this assay to strains TA 1535, TA 1538, TA 98 and TA 100, regardless of the presence or absence of S9 . In the standard overpour Ames test, the drug was non-mutagenic in all 5 Salmonella strains, both with and without S9 metabolic activation. Food Chem Toxicol, 1987 May, 25(5), 373 - 7 In vitro formation of a triazene compound by reaction of sulphadimidine and nitrite; Hoogenboom LA et al.; The interaction between the veterinary drug sodium sulphadimidine and nitrite has been studied under acid conditions and the formation of 1,3-di-(4-{N-(4,6-dimethyl-2-pyrimidinyl)sulphamoylphenyl)triazene (DDPSPT) was demonstrated . This compound was not mutagenic when tested on Salmonella typhimurium and Drosophila melanogaster . In addition to the formation of DDPSPT, desaminosulphadimidine was identified as a minor reaction product. Proc Natl Acad Sci U S A, 1987 May, 84(9), 2718 - 22 N-terminal methionine-specific peptidase in Salmonella typhimurium; Miller CG et al.; Crude extracts of a multiply peptidase-deficient strain of Salmonella typhimurium contain an aminopeptidase that specifically removes N-terminal methionine from peptides . This activity shows pronounced specificity for the peptide's second amino acid . Methionine is removed from peptides with alanine, threonine, or glycine in this position but not when the second amino acid is leucine or methionine . The activity is stimulated by Co2+ and is inhibited by EDTA . Mutations that lead to overproduction (up to 30-fold) of the activity have been obtained by selecting for growth on Met-Gly-Gly as a methionine source . These mutations map at approximately 3 map units, phage P22 cotransducible with leu . The overproducer mutations are dominant to wild type, and duplication of the wild-type allele of the locus leads to a gene dosage effect on peptidase levels . This suggests that the locus of the overproducer mutations may be the structural gene for the peptidase . NaDodSO4/PAGE shows an increased level of a single protein (34 kDa) in the overproducer mutant . This protein is highly enriched in a purified preparation of the peptidase . The specificity of this enzyme suggests that it is involved in the cleavage of methionine from newly synthesized peptide chains . This activity can specifically remove methionine from the N terminus of a completed protein . Treatment of purified, unprocessed (N-terminal methionine) interleukin 1 beta with the purified peptidase results in removal of N-terminal methionine with no additional alterations . N-terminal processing of at least this protein can occur after translation is complete . We propose to call this enzyme peptidase M (methionine-specific aminopeptidase). Mol Gen Genet, 1987 May, 207(2-3), 435 - 40 Involvement of ack-pta operon products in alpha-ketobutyrate metabolism by Salmonella typhimurium; Van Dyk TK et al.; The herbicide sulfometuron methyl inhibits acetolactate synthase II of Salmonella typhimurium, resulting in toxic accumulation of alpha-ketobutyrate . Four mutants, containing Tn10 insertions in the acetate kinase (ack) or phosphotransacetylase (pta) genes, were found among a collection of mutants hypersensitive to sulfometuron methyl . The genetic map location of these four Tn10 insertions at 46 min was identical to that of ack and pta point mutants . The insertion and point mutants shared the following phenotypes: resistance to fluoroacetate, sensitivity to alizarin yellow, inability to utilize inositol as a sole carbon source, and hypersensitivity to sulfometuron methyl . Three of the four Tn10 insertion mutants were deficient in phosphotransacetylase but not in acetate kinase activities, indicating insertion of Tn10 in the pta gene . The fourth mutant contained an insertion in the ack gene and was deficient in both acetate kinase and phosphotransacetylase activities . This polarity is consistent with cotranscription of ack and pta . All ack and pta mutants tested were defective in alpha-ketobutyrate turnover . Acetate kinase and phosphotransacetylase are proposed to be part of a pathway for alpha-ketobutyrate metabolism . Propionyl-CoA, an intermediate of that pathway, and propionate, the product of the pathway, accumulated upon inhibition of acetolactate synthase. J Bacteriol, 1987 May, 169(5), 2251 - 8 Regulation of cobalamin biosynthetic operons in Salmonella typhimurium; Escalante-Semerena JC et al.; Transcription of cobalamin (cob) biosynthetic genes in Salmonella typhimurium is repressed by cobalamin and by molecular oxygen . These genes seem to be subject to catabolite repression, and they are maximally expressed under conditions of anaerobic respiration of glycerol-fumarate . A 215-fold increase in the expression of cob genes occurs when S . typhimurium shifts from aerobic growth on glucose to anaerobic respiration of glycerol-fumarate under strictly anoxic growth conditions . Exogenous cyclic AMP substantially stimulates the transcription of cob-lac fusions during aerobic growth . However, cyclic AMP is not absolutely required for the expression of the pathway, nor does it mediate the aerobic control . Cobalamin biosynthesis is not seen under aerobic growth conditions, even when transcription is stimulated by the addition of cyclic AMP . Hence, additional control mechanisms triggered by the presence of molecular oxygen must operate independently from transcription effects on the cob operons. J Bacteriol, 1987 May, 169(5), 1787 - 93 Genetic analysis in Salmonella typhimurium with a small collection of randomly spaced insertions of transposon Tn10 delta 16 delta 17; Kukral AM et al.; We report the isolation of a group of 279 Salmonella typhimurium strains carrying randomly spaced insertions of the minitransposon Tn10 delta 16 delta 17 and describe the use of these strains to facilitate genetic analysis . The insertions were isolated initially in individual recombinant lambda clones from a genomic library . Individual insertions were then moved into the S . typhimurium chromosome, where the distribution of insertion sites relative to standard genetic markers was analyzed in a series of transductional crosses . Since a different, randomly chosen clone was used to generate each insertion, the distribution of insertion positions should have been as random as the cloning events leading to the formation of the library . In agreement with this expectation, most S . typhimurium markers tested were cotransducible with one or more of these Tn10 delta 16 delta 17 insertions . We expect that most new mutations will be quickly classified and mapped by determination of the pattern of cotransduction with this set of insertions . This use is illustrated by the analysis of a group of lac operon fusions regulated by anaerobiosis . We also describe several other applications that should make this collection a useful new tool in S . typhimurium genetics. J Mol Biol, 1987 Apr 20, 194(4), 679 - 90 lambda N antitermination system: functional analysis of phage interactions with the host NusA protein; Schauer AT et al.; Coliphage lambda gene expression is regulated temporally by systems of termination and antitermination of transcription . The lambda-encoded N protein (pN) acting with host factors (Nus) at sites (nut) located downstream from early promoters is the first of these systems to operate during phage development . We report observations on some of the components of this complex system that, in part, address the way in which these elements interact to render RNA polymerase termination-resistant . (1) The isolation of a conditionally lethal cold-sensitive nusA mutation demonstrates that NusA is essential for bacterial growth . (2) The effect on lambda growth in a host in which the Salmonella NusA protein is overproduced suggests that NusA is essential for N-mediated antitermination in phage lambda . (3) A truncated NusA product, representing only the amino two-thirds of the native protein, is active for both bacterial growth and pN action, indicating that the carboxy end of the molecule may not be a functionally important region . (4) lambda pN can function with the heterologous nut region from Salmonella typhimurium phage P22 when lambda pN is overproduced, demonstrating that lambda pN can function with the nut regions of other lambdoid phages . (5) A single base-pair change in the lambda nutR boxA sequence that was selected to permit a lambda derivative to utilize the Salmonella NusA protein restores lambda growth in the Escherichia coli nusA1 host. J Mol Biol, 1987 Apr 20, 194(4), 635 - 42 Differences between transfer RNA molecules; McClain WH et al.; Computer-assisted comparisons of 67 tRNA sequences that function in Escherichia coli or Salmonella typhimurium were used to identify single and multiple nucleotide positions that maximally distinguish the 20 amino acid acceptor groups . Positions in the anticodon were identified most frequently, as expected from the decoding function of this region of the tRNA . The biological function, if any, of positions outside the anticodon may include specificity for aminoacyl-tRNA synthetase enzymes. J Biol Chem, 1987 Apr 5, 262(10), 4740 - 7 Structure and biological relationships of Coxiella burnetii lipopolysaccharides; Amano K et al.; Lipopolysaccharides (LPSs) extracted from nine strains of Coxiella burnetii were analyzed for chemical compositions, molecular heterogeneity by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and lethal toxicities in galactosamine-sensitized mice . The structure of a unique disaccharide of hydrolyzed phase I LPS was determined to be galactosaminuronyl-alpha (1-6)-glucosamine (GalNU-alpha (1-6)-GlcN, C12H22N2O10) with an Mr of 354 . The Mr of LPSs of C . burnetii intra- and interspecific strains and the content of GalNU-alpha (1-6)-GlcN and two sugars, virenose and dihydrohydroxystreptose, were used as biochemical markers of truncated LPSs . Smooth-phase I LPS contained all three compounds, semi-rough-phase I LPS did not contain virenose, and rough-phase II LPS contained none of the three compounds . These analyses indicate that the intermediate to larger Mr LPSs require the addition of GalNU-alpha (1-6)-GlcN and dihydrohydroxystreptose to obtain the major (10.5 kDa), the intermediate (between 10.5 and 27 kDa), and the minor (23 kDa) LPS bands . The addition of virenose to the major and the minor bands produced the large Mr phase I LPSs . Extreme microheterogeneity in the banding profile ranging in Mr from the 2.5 to 10.5 kDa may be due to unidentified components, while the microheterogeneity in Mr of the 10.5-kDa and larger LPS bands is related to variations in the compounds described here . All of the LPSs were toxic in galactosamine-sensitized mice, albeit they were 100-1000-fold less toxic than Escherichia coli and Salmonella typhimurium endotoxin. J Mol Biol, 1987 Apr 5, 194(3), 443 - 52 Transcription termination sites at the distal end of the leu operon of Salmonella typhimurium; Rosenthal ER et al.; Transcription terminates at two different sites at the distal end of the leucine operon of Salmonella typhimurium . The first of these sites (leut), located 140 base-pairs past the end of leuD, contains a G + C-rich palindrome followed by a run of T residues in the non-coding strand . Termination at leut, both in vitro and in vivo, is independent of rho protein, but is stimulated by the NusA protein . The second termination site (leut'), located 145 base-pairs beyond the first, is rho-dependent both in vitro and in vivo, and is not influenced by NusA protein . The organization of transcription termination sites at the distal end of the leu operon (a rho-independent site followed by a rho-dependent site) is similar to that for the trp operon of Escherichia coli. Food Chem Toxicol, 1987 Apr, 25(4), 331 - 5 Commercial hickory-smoke flavouring is a human lymphoblast mutagen but does not induce lung adenomas in newborn mice; Braun AG et al.; Commercial aqueous wood-smoke flavouring induced significant increases in the 6-thioguanine resistance mutation frequency of TK6 human lymphoblasts at 0.1 microliter flavouring/ml of cell suspension . This corresponds to 6 micrograms/ml of dissolved 'solids' as determined by fully drying the aqueous flavouring in a vacuum desiccator . In AHH-1 human lymphoblasts, which contain a cytochrome P-450 monooxygenase system, mutations were induced at 0.3 microliter/ml, corresponding to 18 microliters/ml of dissolved 'solids' . The flavouring did not induce 8-azaguanine resistant mutations in Salmonella typhimurium at concentrations up to 1.5 microliter/ml . At higher concentrations the flavouring was toxic to bacteria . The flavouring did not induce lung adenomas or other tumours in newborn mice when injected ip with total doses of up to 26 microliters over a 3-wk period . Toxicity to the kidney, colon and rectum was observed in some mice at 15 wk of age. J Clin Microbiol, 1987 Apr, 25(4), 702 - 5 Evaluation of immuno-dot-blot assay for detection of cholera-related enterotoxin antigen in Salmonella typhimurium; Panigrahi D et al.; Twenty-five strains of Salmonella typhimurium isolated in India were examined for the presence of cholera/coli-related enterotoxin antigen by a previously described latex particle agglutination test and by a newly developed immuno-dot-blot test using immunopurified goat antibody against the cholera-related enterotoxin isolated from an Escherichia coli strain of human origin . The immuno-dot-blot assay could detect 0.02 ng of purified enterotoxin . The amount of toxin antigen detected varied widely from strain to strain . Fourteen of the 25 polymyxin B-treated extracts of bacteria harvested from 6-h Casamino Acids-yeast extract broth cultures gave positive results in both serologic assays as well as in rabbit skin tests for delayed permeability factor . An additional strain was positive only in the immuno-dot-blot . Five of six stool isolates and six of seven blood isolates tested gave positive reactions . Two isolates of Salmonella enteritidis tested were also positive . The immuno-dot-blot test appears to be a simple, rapid, and reliable method for detection of cholera-related enterotoxin antigen in S . typhimurium . The demonstration of a cholera-related enterotoxin, even in small amounts, in a facultative intracellular pathogen raises interesting questions regarding its potential role in pathogenesis both of diarrheal disease and systemic infections caused by salmonellae. Mutat Res, 1987 Apr, 190(4), 241 - 6 Mutagenicity-enhancing effect of quercetin on the active metabolites of 2-acetylaminofluorene with mammalian metabolic activation systems; Ogawa S et al.; The effects of quercetin on the mutagenicity of 2-acetylaminofluorene (AAF) and its 3 active metabolites, N-hydroxy-AAF (N-OH-AAF), aminofluorene (AF) and N-acetoxy-AAF(N-OAc-AAF) were investigated . The mutagenicity assays were carried out with Salmonella typhimurium TA98, and S9, microsomes and cytosol were used as metabolic activation systems . In the presence of S9, quercetin enhanced the mutagenicity of AAF, N-OH-AAF, AF and N-OAc-AAF by 6.9-, 4.3-, 3.6- and 3.9-fold, respectively . Quercetin enhanced the mutagenicity of these substrates with microsomes, whereas it depressed the mutagenicity of these substrates with cytosol . From these results, it seemed probable that quercetin promotes the N-hydroxylation and deacetylation in the microsomes, whereas it inhibits the deacetylation in the cytosol . It was shown that in the metabolism of AAF and its metabolites, quercetin modulates the balance between the mutagenicity activation and inactivation processes, which is catalysed by the enzymes in the microsomes and cytosol, and causes enhancement of the mutagenicity of AAF. Mutat Res, 1987 Apr, 187(4), 191 - 7 Structure-mutagenicity relationship among aminoquinolines, aza-analogues of naphthylamine, and their N-acetyl derivatives; Takahashi K et al.; The mutagenicity of 7 positional isomers of aminoquinolines (AQ) and their N-acetyl derivatives (AcAQ) was tested in Salmonella typhimurium TA100 and TA98 in the presence and absence of S9 mix . In a series of aminoquinolines, the order of mutagenic potency in the presence of S9 mix is: 5-AQ greater than 8-AQ greater than 7-AQ greater than 3-AQ greater than 2-AQ much greater than 4-AQ, 6-AQ . The alpha-positional isomers, 5-AQ and 8-AQ, are more mutagenic than the beta-isomer, 2-, 3-, 6-, 7-AQ's . These results are in contrast to the finding that beta-naphthylamine is more mutagenic than alpha-naphthylamine . In a series of N-acetylaminoquinolines, the order of mutagenic potency in the presence of S9 mix is: 7-AcAQ greater than 6-AcAQ greater than 8-AcAQ much greater than all the others . It is suggested that the AQ and AcAQ series might exert their mutagenicity through different molecular mechanisms (i.e., metabolic activation) from each other . The rate of metabolic activation does not seem to be correlated with the mutagenic potency of the compounds . It is noteworthy that 7-AQ and 8-AQ are mutagenic in both the strains tested in the absence of S9 mix. Mutat Res, 1987 Apr, 187(4), 181 - 90 Comparative genotoxic effects of IQ and MeIQ in Salmonella typhimurium and cultured mammalian cells; Holme JA et al.; The food mutagens 2-amino-3-methylimidazo{4,5-f}quinoline (IQ) and 2-amino-3,4-dimethylimidazo{4,5-f}quinoline (MeIQ) were studied for their genotoxic potential using hepatocytes isolated from untreated and Aroclor 1254 (PCB) pretreated rats as an activation system . Monolayers of hepatocytes co-incubated with Salmonella typhimurium TA98 activated IQ and MeIQ to bacterial mutagens, with MeIQ being about twice as potent as IQ . The mutagenic activities of IQ and MeIQ were increased by using hepatocytes from PCB-pretreated rats . IQ and MeIQ also caused primary DNA damage in the hepatocytes as determined by increases in the rate of alkaline elution of DNA, as well as increases in DNA-repair synthesis . Furthermore, exposure of V79 cells co-cultured with PCB-pretreated hepatocytes to IQ and MeIQ showed evidence of increased sister-chromatid exchanges and a low and variable increase in the number of 6-thioguanine-resistant mutants . The genotoxic potency of IQ and MeIQ in mammalian cells was low or virtually absent compared to their extreme potency in bacteria . This could be due to a lower capacity of mammalian cells to further metabolize the so-called directly acting bacterial mutagens, formed by a cytochrome P-450 dependent N-hydroxylation, to their ultimate reactive forms. Mutat Res, 1987 Apr, 177(2), 241 - 6 Acid-mediated mutagenicity of tobacco snuff: its possible mechanism; Whong WZ et al.; Polar solvent extracts of tobacco snuff under acidic conditions were mutagenic in Salmonella typhimurium . Using the Griess reagent test, nitrite ranging from approximately 1.8 to 5.4 mg/g of snuff was found in the polar fraction of extracts . After acid treatment, nitroso compounds in the amount corresponding to the nitrite concentration were detected . The mutagenic potency of the acid-treated extracts was consistent with the content of nitroso compounds generated . Formation of nitroso compounds and the mutagenic activity under acidic conditions was inhibited by ascorbic acid . The results indicate that a nitrosation process was involved in snuff extracts during acid treatment . Studies related to the source of nitrite in tobacco snuff demonstrated that snuff contained bacteria which were able to reduce nitrate to nitrite and that the amount of nitrite in snuff extracts could be further increased by incubation of the extracts with the bacteria . Since snuff contains a considerable amount of nitrate, it seems that reduction of nitrate in snuff to nitrite by bacteria, and nitrosation of certain constituents in snuff by nitrite under acidic conditions to form mutagenic nitroso compounds are possible mechanisms responsible for the acid-mediated mutagenicity of snuff extracts. J Bacteriol, 1987 Apr, 169(4), 1767 - 71 Conditional transduction of Salmonella typhimurium envB mutations; Anton DN; Joint transduction of the argR and envB genes was observed, at a frequency of 24.5%, when four envB strains were transduced to tetracycline resistance (Tetr) with bacteriophage P22 grown on an argR372::Tn10 envB+ donor . When round-cell argR372::Tn10 derivatives of those envB strains were used as donors, two of them did not produce envB transductants in wild-type LT2 and other envB+ recipients, even though large numbers of Tetr transductants were obtained . This apparent exclusion of envB mutations did not occur when mecillinam-resistant derivatives of those envB+ strains were used as recipients . Mutations conferring partial resistance to mecillinam were found, unlinked to the argR-envB region, in three of the four envB strains studied; envB+ derivatives of the four strains were competent to accept envB mutations excluded by wild-type recipients . It is suggested that some envB mutations are lethal in the absence of suppressor mutations, some of which increase resistance to mecillinam. J Bacteriol, 1987 Apr, 169(4), 1493 - 8 The flaFIX gene product of Salmonella typhimurium is a flagellar basal body component with a signal peptide for export; Homma M et al.; flaFIX, the structural gene for the periplasmic P ring of the flagellar basal body of Salmonella typhimurium, was cloned . Two gene products with apparent molecular weights of 38,000 and 40,000 were identified by minicell analysis . Data from pulse-chase and membrane fractionation experiments and data on the inhibitory effect of the proton ionophore carbonyl cyanide m-chlorophenylhydrazone all indicated that the 40-kilodalton protein was a precursor form which, after export across the cytoplasmic membrane accompanied by cleavage of a signal peptide, gave rise to the mature protein in the periplasm . The N-terminal amino acid sequence of the FlaFIX protein, predicted from the DNA sequence, conformed well to known signal peptide sequences . The results indicate that the P-ring protein of the basal body (unlike flagellin and possible some other external flagellar components) crosses the cytoplasmic membrane in a conventional signal peptide-dependent manner. J Bacteriol, 1987 Apr, 169(4), 1489 - 92 Identification of proteins of the outer (L and P) rings of the flagellar basal body of Escherichia coli; Jones CJ et al.; Synthesis of the Salmonella typhimurium hook protein from the gene cloned on a multicopy plasmid results in partial suppression of the flagellar assembly defects of certain classes of Escherichia coli mutants (K . Ohnishi, M . Homma, K . Kutsukake, and T . Iino, J . Bacteriol, 169:1485-1488, 1987) . This phenomenon allowed hook-basal body complexes from such mutants to be purified and analyzed by electron microscopy and gel electrophoresis . The absence of the P and L rings in such structures was found to correlate with the absence of proteins of apparent molecular weight 39,000 and 26,000, respectively . Gene-polypeptide correlations from other studies enabled us to complete gene-polypeptide-structure correspondences for these two proteins as flaM----39-kilodalton protein----P ring and flaY----26-kilodalton protein----L ring. J Bacteriol, 1987 Apr, 169(4), 1485 - 8 Formation of flagella lacking outer rings by flaM, flaU, and flaY mutants of Escherichia coli; Ohnishi K et al.; Among flagellar mutants of Escherichia coli, flaM or flaU mutants form basal bodies lacking the outer P and L rings, whereas flaY mutants predominantly form basal bodies lacking the L ring . In these mutants, hooks and filaments are occasionally assembled onto these incomplete basal bodies . When the hook protein gene, flaFV, of Salmonella typhimurium was cloned on the multicopy plasmid pBR322 and introduced into these mutants, the efficiency with which cells assembled hooks and filaments onto the incomplete basal bodies increased significantly . Such cells formed characteristic dotted swarms on semisolid plates, indicating that cells carrying flagella without the outer rings are weakly motile because of poor function of their flagella, a low flagellar number per cell, or both of these defects . FlaV mutants also produced incomplete basal bodies lacking the outer rings, but assembly of hooks and filaments did not occur in these mutants even after introduction of the plasmid carrying flaFV of S . typhimurium . The failure in the case of flaV mutants was attributed to their inability to modify the rod tip to the structure competent for assembly of hook protein. J Bacteriol, 1987 Apr, 169(4), 1391 - 7 A new methionine locus, metR, that encodes a trans-acting protein required for activation of metE and metH in Escherichia coli and Salmonella typhimurium; Urbanowski ML et al.; We isolated an Escherichia coli methionine auxotroph that displays a growth phenotype similar to that of known metF mutants but has elevated levels of 5,10-methylenetetrahydrofolate reductase, the metF gene product . Transduction analysis indicates that the mutant carries normal metE, metH, and metF genes; the phenotype is due to a single mutation, eliminating the possibility that the strain is a metE metH double mutant; and the new mutation is linked to the metE gene by P1 transduction . Plasmids carrying the Salmonella typhimurium metE gene and flanking regions complement the mutation, even when the plasmid-borne metE gene is inactivated . Enzyme assays show that the mutation results in a dramatic decrease in metE gene expression, a moderate decrease in metH gene expression, and a disruption of the metH-mediated vitamin B12 repression of the metE and metF genes . Our evidence suggests that the methionine auxotrophy caused by the new mutation is a result of insufficient production of both the vitamin B12-independent (metE) and vitamin B12-dependent (metH) transmethylase enzymes that are necessary for the synthesis of methionine from homocysteine . We propose that this mutation defines a positive regulatory gene, designated metR, whose product acts in trans to activate the metE and metH genes. Carcinogenesis, 1987 Apr, 8(4), 515 - 20 The 32P-post-labeling method in quantitative DNA adduct dosimetry of 2-acetylaminofluorene-induced mutagenicity in Chinese hamster ovary cells and Salmonella typhimurium TA1538; Arce GT et al.; The usefulness of the 32P-post-labeling/t.l.c . method for quantitative DNA adduct dosimetry was evaluated . 2-Acetylaminofluorene (2-AAF)-DNA adducts from three systems were characterized qualitatively and quantitatively by the 3H-radiolabeled technique with subsequent analysis by h.p.l.c . (pre-labeling method) and by the 32P-post-labeling method . Both methods showed N-acetoxyacetylaminofluorene (N-OAc-AAF) reaction products with calf thymus DNA were predominantly N-(deoxyguanosin-8-yl)-2-acetylaminofluorene (dG-C8-AAF) with some N-(deoxyguanosin-8-yl)-2-aminofluorene (dG-C8-AF) and N-(deoxyguanosin-N2-yl)-2-acetylaminofluorene (dG-N2-AAF) . In contrast, Chinese hamster ovary (CHO) cells treated with {3H}N-OAc-AAF gave 80 or 90% dG-C8-AF adducts and 20 or 10% dG-C8-AAF adducts with the post- or pre-labeling method, respectively . Likewise in CHO cells treated with 2-AAF in the presence of rat liver homogenate, approximately 90% dG-C8-AF and 10% dG-C8-AAF adducts were detected using the 32P-post-labeling method . In Salmonella typhimurium strain TA1538 treated with 2-AAF or {3H}2-AAF in the presence of a rat liver homogenate, one adduct, dG-C8-AF, was identified . Similar quantitative results were also obtained with the two methods . However, the 32P-post-labeling method was more sensitive and also eliminated the use of radiolabeled-mutagen treatments . Quantitative DNA adduct dosimetry was applied to AAF-induced mutagenesis in the S . typhimurium and CHO/HPRT mutation assays . A linear and reproducible relationship existed between dG-C8-AF levels and AAF-induced mutants in both systems. Cancer Res, 1987 Apr 1, 47(7), 1811 - 4 Mutagenicity experiments on agroclavines, new natural antineoplastic compounds; Glatt H et al.; Agroclavine, an alkaloid produced by some species of fungi and dicotyledon plants, and its 1-alkylated derivatives are potentially useful as antineoplastic drugs, since they exert potent and selective cytostatic effects . In the present study, we have investigated agroclavine and its 1-propyl and 1-pentyl derivatives for mutagenicity . The genetic end point studied was the reversion of strains of Salmonella typhimurium (TA 100, TA 98, TA 1537) and Escherichia coli (WP2 uvrA), auxotrophic for histidine and tryptophan, respectively . The compounds were tested directly and in the presence of a mammalian xenobiotic-metabolizing system . In the direct test, agroclavine and the two alkylated derivatives examined exhibited substantial bacteriotoxicity but no mutagenicity . Addition of NADPH-fortified postmitochondrial supernatant fraction of rat liver homogenate led to a clear-cut decrease in bacteriotoxicity and to the formation of mutagenic products . Each compound was effective in all three strains of S . typhimurium used . In E . coli only spurious effects were seen . 1-Pentylagroclavine, the most hydrophobic compound in the series, was the strongest mutagen . Agroclavine, the least hydrophobic compound, was the weakest . The mutagenic potencies and efficacies of all these test compounds were much weaker than those of the positive controls, which were known mutagens and carcinogens . Moreover, the differential effect of metabolism by liver enzymes demonstrates that the toxicity and mutagenicity of agroclavine and its derivatives are caused by different chemical species . Hence, it may be possible to develop derivatives that are cytotoxic but not mutagenic. Proc Natl Acad Sci U S A, 1987 Apr, 84(7), 1769 - 73 Structure of human lactoferrin at 3.2-A resolution; Anderson BF et al.; The three-dimensional structure of human milk lactoferrin, a member of the transferrin family, has been determined crystallographically at 3.2-A resolution . The molecule has two-fold internal homology . The N- and C-terminal halves form two separate globular lobes, connected by a short alpha-helix, and carry one iron-binding site each . Each lobe has the same folding, based on two domains of similar supersecondary structure, with the iron site at the domain interface . Each iron atom is coordinated by four protein ligands: two tyrosines, one histidine, and one aspartate . A probable CO3(2-) (or HCO3-) ion is suggested by the electron density, bound to iron and adjacent to an arginine side chain and a helix N terminus . The protein folding and location of the binding sites show marked similarities with those of other binding proteins, notably the sulfate-binding protein from Salmonella typhimurium. Poult Sci, 1987 Apr, 66(4), 760 - 1 Invasion of Salmonella typhimurium into the cecal wall of gnotobiotic chickens with Eimeria tenella; Fukata T et al.; Salmonella typhimurium was recovered from cecal contents and the cecal wall of gnotobiotic chickens infected with S . typhimurium (10(4) cfu/bird) 2, 4, 6, or 8 days after Eimeria tenella infection (5 X 10(4) oocysts/bird) and killed 1 day after S . typhimurium infection . Bacterial counts in the cecal contents of chickens killed 5, 7, and 9 days after S . typhimurium and E . tenella infection were significantly greater than those in chickens infected with S . typhimurium alone . Number of S . typhimurium in the cecal wall of birds killed 5 or 7 days after coccidial infection were significantly greater than those of birds infected with S . typhimurium alone . It appears that S . typhimurium easily invaded the cecal wall, which had been damaged by coccidial infection. Microbiologica, 1987 Apr, 10(2), 183 - 8 Antibiotic resistance and R plasmids in endemic strains of Salmonella typhimurium isolated in Sicily; Giammanco G et al.; The characteristics of R plasmids in strains of Salmonella typhimurium isolated in Sicily during 1983 from apparently isolated cases of human infection have been determined . A plasmid of the Inc group 10-B-0, characterized by ApSm resistance markers and with a molecular weight of 70 Md, was found in strains belonging to different phage types (2, 3, 117, 135, NT) . The data obtained suggest that strains of the same phage type harboring such plasmids come from the same bacterial clone which has continued to be endemic through interhuman contagion . Instead, the presence of the same plasmid in strains of different phage type could indicate its spreading in different bacterial clones. Mutat Res, 1987 Apr, 177(2), 229 - 39 Inhibitory effect of phenolic compounds on aflatoxin B1 metabolism and induced mutagenesis; San RH et al.; The interaction between phenolic compounds and the food-borne carcinogenic mycotoxin, aflatoxin B1 (AFB1), was examined . 6 phenolic compounds (gallic acid, chlorogenic acid, caffeic acid, dopamine, p-hydroxybenzoic acid and salicylic acid) inhibited AFB1-induced mutagenesis in Salmonella typhimurium strain TA98 in a suspension assay in the presence of rat-liver microsomes (S9) . The inhibitory effect was observed when the phenolic compound and the mutagen (AFB1 plus S9) were administered concurrently, but not when exposure to the mutagen was followed by the phenolic compound . The concentrations of the phenolic compounds used were not mutagenic to S . typhimurium strain TA98 and had no effect on the survival of the bacteria . The inhibition of AFB1 metabolism was studied using high-pressure liquid chromatography . Increasing the concentration of all 6 phenolic compounds resulted in a dose-dependent reduction of both major AFB1 metabolite peaks . The results are consistent with the hypothesis that the phenolic compounds do not react covalently with AFB1, and the inhibitory effect of phenolic compounds on AFB1-induced mutagenesis may be due to the inhibition of the activation enzymes. Carcinogenesis, 1987 Apr, 8(4), 541 - 5 Prostaglandin H synthase-dependent mutagenic activation of heterocyclic aromatic amines of the IQ-type; Wild D et al.; Microsomes from ram seminal vesicles known as a rich source of prostaglandin H synthase (PHS) activate the food mutagen IQ (2-amino-3-methylimidazo{4,5-f}quinoline) to (a) product(s) mutagenic in Salmonella typhimurium TA98 . The activation is dependent on the PHS cofactor arachidonic acid and is strongly inhibited by the PHS inhibitor indomethacin . In this system, the mutagenic potency of IQ is 22 and 110 times higher than that of 2-aminofluorene and benzidine, respectively . The high mutagenic potency of IQ observed previously with mono-oxygenase activation is thus extended to the PHS system . The mutagenic activity produced by PHS increases for 4 h; this contrasts with the relatively short lifetime of the activity produced by mono-oxygenase and suggests that different agents are involved in the two processes . The PHS-mediated mutagenic activity of IQ is strongly dependent on the bacterial O-acetyltransferase which is defective in strain TA98/1,8-DNP6 . Further, the responses of the strains TA1978 and TA1538 indicate that the mutagenic activity is dependent on lack of the bacterial DNA excision repair and independent of the plasmid pkM101 coded error-prone DNA repair system . Structural analogs of IQ without a methyl group on the imidazole ring and with a naphthalene instead of the quinoline ring show greatly diminished PHS-mediated mutagenic activity . The strain response pattern and structure-activity relationships are similar to those found with mono-oxygenase activation of IQ and thus indicate a basic similarity of the IQ activation via PHS with that via mono-oxygenase . It is hypothesized that PHS may activate carcinogenic heterocyclic aromatic amines in vivo. Mol Gen Genet, 1987 Apr, 207(1), 120 - 9 OmpR and EnvZ are pleiotropic regulatory proteins: positive regulation of the tripeptide permease (tppB) of Salmonella typhimurium; Gibson MM et al.; The tppB locus of Salmonella typhimurium encodes the anaerobically-induced tripeptide permease . We have demonstrated that expression of tppB requires the function of the ompR and envZ gene products, originally identified as positive regulatory proteins required for the osmotic regulation of porin expression . Significantly, tppB expression is not osmotically regulated . We have also identified three additional genes whose expression depends on OmpR . Thus OmpR and EnvZ serve a more general regulatory role than has previously been supposed . This study provides the first detailed genetic analysis of the ompB locus of S . typhimurium. Mutat Res, 1987 Apr, 187(4), 199 - 207 Photochemical instability of 1-nitropyrene, 3-nitrofluoranthene, 1,8-dinitropyrene and their parent polycyclic aromatic hydrocarbons; Holloway MP et al.; The environmental contaminants pyrene, 1-nitropyrene, 1,8-dinitropyrene, fluoranthene, and 3-nitrofluoranthene were exposed to light (greater than or equal to 310 nm) either in DMSO, or following coating onto silica . Under all conditions tested the pyrenyl were less stable than the fluoranthenyl compounds . During irradiation in DMSO or on silica, 1-nitropyrene had half-lives of 1.2 and 6 days, while those of 3-nitrofluoranthene were 12.5 and greater than 20 days, respectively . The photodecomposition of 1,8-dinitropyrene resembled that of 1-nitropyrene with half-lives of 0.7 and 5.7 days . A principle photodecomposition product of 1,8-dinitropyrene was identified as 1-nitropyren-8-ol . It was also found that when the nitroarenes were exposed to light, the loss of compound was associated with a concomitant loss of mutagenicity in Salmonella typhimurium strain TA98 . The mechanism of nitrated polycyclic aromatic hydrocarbon decomposition and 1-nitropyren-8-ol formation, and the relevance to the atmospheric disposition of these compounds are discussed. J Bacteriol, 1987 Apr, 169(4), 1372 - 8 Toxic accumulation of alpha-ketobutyrate caused by inhibition of the branched-chain amino acid biosynthetic enzyme acetolactate synthase in Salmonella typhimurium; LaRossa RA et al.; Biochemical and genetic analyses of the bacterium Salmonella typhimurium suggest that accumulation of alpha-ketobutyrate partially mediates the herbicidal activity of acetolactate synthase inhibitors . Growth inhibition of wild-type bacteria by the herbicide sulfometuron methyl was prevented by supplementing the medium with isoleucine, an allosteric inhibitor of threonine deaminase-catalyzed synthesis of alpha-ketobutyrate . In contrast, isoleucine did not rescue the growth of a mutant containing a threonine deaminase unresponsive to isoleucine . Moreover, the hypersensitivity of seven Tn10 insertion mutants to growth inhibition by sulfometuron methyl and alpha-ketobutyrate correlated with their inability to convert alpha-ketobutyrate to less noxious metabolites . We propose that alpha-ketobutyrate accumulation is an important component of sulfonylurea and imidazolinone herbicide action. Zh Mikrobiol Epidemiol Immunobiol, 1987 Apr, (4), 3 - 8 {Genetic characteristics and protective properties of neamin-resistant mutant Salmonella typhimurium and S . dublin of the Nea(r) Str(s) and Nea(r) Str(r) 500 classes}; Marakusha BI et al.; The genetic analysis of attenuated mutants, class Nea(r) Str(s), with the use of bacteriophage P 22 has shown that mutation rendering the mutants resistant to neamine is localized in gene nea A . In experiments with the intraperitoneal infection of mice, the appearance of this mutation in S . typhimurium and S . dublin virulent strains has been found to lead to the decrease of virulence in 100% of clones . On the basis of the data obtained in this investigation, region str-spc in S . typhimurium and S . dublin has been mapped . In contrast to mutation spc A, mutations nea A and str A have been shown to inhibit the action of amber suppressor . The investigation has confirmed the regularity, previously established for Shigella flexneri, concerning the relationship between the influence of mutations, occurring in the genes which determine resistance to neamine and streptomycin and control the synthesis of ribosomal proteins S4, S5, S12 and S17, on the virulence of S . typhimurium and S . dublin and the effect of these mutations on the accuracy of the translation of genetic information in the biosynthesis of protein: mutation spc A has been found to produce no changes in the virulence of salmonellae, while mutations nea A and str A cause its loss . Salmonella strains carrying mutations nea A and nea B have shown pronounced protective properties in experiments on mice. J Gen Microbiol, 1987 Apr, 133 ( Pt 4), 953 - 60 Phage tf-1: a filamentous bacteriophage specific for bacteria harbouring the IncT plasmid pIN25; Coetzee JN et al.; Phage tf-1 is a filamentous phage which is about 800 nm in length, 10 nm in width and has slightly tapered ends . The phage was isolated from sewage and formed plaques or propagated only on Escherichia coli, Salmonella typhimurium and Klebsiella oxytoca strains harbouring the IncT plasmid pIN25 at 30 degrees C . It adsorbed in large numbers to pIN25-encoded long thick flexible conjugative pili formed at 30 degrees C and also to the short form of these pili synthesized at 37 degrees C . The reason for the failure to form plaques at 37 degrees C is not known . The adsorption site is a short length of the pilus shaft extending 100-200 nm back from the distal tip . Efficient phage tf-1 adsorption to the same site was found for pili determined by other IncT plasmids in spite of the fact that phage tf-1 did not plate or propagate on strains harbouring them . However, areas of specific partial clearing on lawns of these plasmid-containing bacteria were produced by phage in high concentrations . Lack of plaque-formation could be due to inefficient intracellular assembly coupled to avid adsorption of any liberated phage to pili . The phage differs from all but one other filamentous phage by being sensitive to diethyl ether. Mol Toxicol, 1987 Apr-Sep, 1(2-3), 247 - 59 Macrophage functional activities versus cellular parameters upon sublethal pesticide exposure in mice; Krzystyniak K et al.; The toxicity of selected organochlorine, organophosphate, and carbamate pesticides on the functions and cellular parameters of peritoneal macrophages was examined in inbred C57Bl/6 mice . Effects of single, sublethal pesticide exposure on macrophages were determined by analysis of the cell viability, cell adherence capacity, generation of superoxide anion (O2-), antigen processing, phagocytosis of Salmonella typhimurium, and resistance to in vitro virus-induced cytopathic effects (cpe) after infection with mouse hepatitis virus 3 (MHV3) . Most of the studies were done for the organochlorine pesticide dieldrin, which inhibited several macrophage functions, such as phagocytosis of S . typhimurium, release of the single processed protein antigen avidin, and resistance to MHV3 virus-induced cpe . The virus-induced cytolysis in macrophage cultures was significantly increased after in vivo exposure to single sublethal doses of other selected pesticides, such as guthion, carbofuran, sevin, and matacil . However, none of the selected pesticides, used in sublethal (0.4 less than or equal to LD50 less than or equal to 0.6) doses appeared to be a factor impairing the O2- -generating system in chemically elicited or immunologically activated peritoneal macrophages . In conclusion, sublethal pesticide exposure can induce a significant impairement of several macrophage functions, such as phagocytosis, antigen processing, and resistance to virus-induced cytolysis . Inhibition of the O2- -generating system by sublethal pesticide exposure, however, can be excluded as a mechanism of potential suppressory action of these pesticides on antiviral and antibacterial host defence systems in which macrophages play a primary role. Nucleic Acids Res, 1987 Mar 25, 15(6), 2653 - 64 Nucleotide sequence and expression of the cloned gene of bacteriophage SP6 RNA polymerase; Kotani H et al.; The coding region of the gene for bacteriophage SP6 RNA polymerase was cloned into pBR322, and its entire nucleotide sequence was deduced . The predicted amino acid sequence for the polymerase consists of 874 amino acid residues with a total molecular weight of 98,561 daltons . Comparison of the amino acid sequence with that of T7 RNA polymerase reveals that regions with partial homology are present along the sequence . The coding region of SP6 RNA polymerase was inserted into an E . coli expression vector . The polymerase gene was efficiently expressed in E . coli cells, and the enzymatic properties of the expressed polymerase were very similar to those of the enzyme synthesized in SP6 phage-infected Salmonella typhimurium cells. Cancer Res, 1987 Mar 15, 47(6), 1509 - 15 Rat hepatocyte-mediated bacterial mutagenicity in relation to the carcinogenic potency of benz(a)anthracene, benzo(a)pyrene, and twenty-five methylated derivatives; Utesch D et al.; 7,12-Dimethylbenz(a)anthracene, benz(a)anthracene, and benzo(a)pyrene as well as the 24 monomethylbenzo(a)pyrenes (MBPs) and monomethylbenz(a)anthracenes (MBAs), compounds which differ in carcinogenicity from very potent to apparently inactive, were investigated for mutagenicity (reversion to histidine prototrophy) in Salmonella typhimurium TA100 using either intact or NADPH-fortified homogenized rat hepatocytes for metabolic activation . In both systems, all 27 hydrocarbons showed positive responses . Their mutagenic potency in the homogenate-mediated test varied in a narrow range and did not correlate detectably with their reported activity in carcinogenicity experiments . When the cell homogenate was replaced by intact cells, the maximal mutagenic effects were weaker by factors of 1 to 14, depending on the compound, and were seen only at higher substrate concentrations . The differences between cell- and homogenate-mediated mutagenicity were small with the strong carcinogens 7,12-dimethylbenz(a)anthracene 7-MBA, 12-MBA, benzo(a)pyrene, 1-MBP, and 11-MBP . The differences were large with the apparent noncarcinogens and those weak carcinogens that were strongly mutagenic in the homogenate-mediated test . As a result of this differential reduction in activity, the cell-mediated mutagenicity did not correlate with the homogenate-mediated mutagenicity but correlated approximately with the carcinogenic potency . The lowest effects in the cell-mediated experiments were seen with 7-, 8-, 9- and 10-MBP, 2-MBA, and 3-MBA . In these compounds, the methyl group is attached to a carbon of the terminal angular benzo ring, and therefore bay-region diol-epoxides, if formed at all, additionally would carry a methyl group on one of the oxidized positions . On the other hand, among all the compounds tested 7,12-dimethylbenz(a)anthracene, 12-MBA, and 11-MBP, which have the methyl group attached in the bay-region position opposite the terminal benzo ring, showed the highest mutagenic efficacies in the cell-mediated test, as compared to those observed in the homogenate-mediated test . These structure-activity relationships and the previously reported observation that among various promutagenic benzo(a)pyrene metabolites only the 7,8-dihydrodiol was strongly mutagenic in the cell-mediated test would suggest that in the cell-mediated bacterial mutagenicity test, bay-region diol-epoxides are the ultimate mutagens which are preferentially detected. Cancer Res, 1987 Mar 1, 47(5), 1287 - 96 Carcinogenicity of mutagens: predictive capability of the Salmonella mutagenesis assay for rodent carcinogenicity; Zeiger E; A total of 224 chemicals that have been tested in long-term studies for carcinogenicity in rats and mice by the National Cancer Institute and the National Toxicology Program were tested for mutagenicity in Salmonella typhimurium . Correlations between mutagenicity and carcinogenicity were examined . The influences of chemical structure, rodent species and organ responses, and bacterial strain responses on the carcinogenesis/mutagenesis correlations were also examined . Not all carcinogens induced tumors in both rats and mice . A clear mutagenic or equivocal mutagenic response in Salmonella was predictive for 77% of the carcinogens or equivocal carcinogens, although only 54% of the 149 carcinogens or equivocal carcinogens were mutagens, and 58% of the nonmutagens were carcinogens or equivocal carcinogens . The proportion of mutagens and equivocal mutagens that were not carcinogenic or equivocal was 23% . There was no apparent way to distinguish the mutagenic carcinogens from the mutagenic noncarcinogens by the responses of the specific Salmonella strains . The proportions of different chemical classes in the data base strongly affected the correlations; 40% of the chlorinated carcinogens were mutagens, whereas 75% of the amines and 100% of the nitro-containing carcinogens were mutagens . Because 29% of the chemicals (30% of the carcinogens) were chlorinated, the poor correlation of this class was reflected in the overall correlation . It is concluded that the use of the Salmonella mutagenicity assay is warranted for the identification of carcinogens, but not for noncarcinogens . The proportion of carcinogens detected as mutagens is dependent on the specific classes of chemicals tested and on the rodent species used to define the carcinogens. Food Chem Toxicol, 1987 Mar, 25(3), 225 - 8 Biological and chemical studies on overheated brewed coffee; Sasaki Y et al.; Vapour formed from overheated decaffeinated coffee was condensed and tested for mutagenicity using the Ames assay in Salmonella typhimurium strains TA98 and TA100 . Vapour produced at 73 and 100 degrees C exhibited no mutagenicity . The basic fraction of vapour produced at 350 degrees C showed weak mutagenicity towards strains TA98 with metabolic activation . The chemical analysis of this fraction identified pyridines and pyrazines as the major constituents . None of the compounds identified in this fraction has been reported as mutagenic when tested in the Ames assay. Chem Biol Interact, 1987 Mar, 61(3), 215 - 28 An investigation of the metabolism of N-nitroso-N-methylaniline by phenobarbital- and pyrazole-induced Sprague-Dawley rat liver and esophagus derived S-9; Gold B et al.; The metabolism and mutagenicity of the esophageal carcinogen N-nitroso-N-methylaniline (NMA) was studied using hepatic and esophageal 9000 X g supernatant (S-9) preparations from Sprague-Dawley rats induced with pyrazole and phenobarbital . Only pyrazole-induced hepatic S-9 was able to dose-dependently activate NMA to a mutagen in the Ames assay and specifically in Salmonella typhimurium TA1537 . NMA in the presence of phenobarbital-induced S-9 gave a very weak non-dose dependent mutagenic response . Metabolism of NMA by the two induced hepatic and esophageal S-9 fractions yielded aniline and N-methylaniline (MA) . Phenobarbital-induced S-9 from both tissues also afforded phenol, while none was found with the pyrazole-induced preparations . Phenol formation presumably arose from the direct oxidative demethylation of NMA via a benzenediazonium ion (BDI) intermediate . The results indicate that an important metabolic pathway for NMA, with both inducing agents, entails an initial denitrosation to yield MA, which in turn rapidly undergoes oxidative demethylation to aniline . The conversion of NMA to phenol also suggests that direct demethylation of NMA in the phenobarbital-induced system is an important metabolic pathway. Am J Vet Res, 1987 Mar, 48(3), 504 - 10 Virulence of wild and mutant strains of Salmonella typhimurium in ligated intestinal segments of calves, pigs, and rabbits; Clarke RC et al.; A ligated intestine model in calves, pigs, and rabbits was tested for its value as an indicator of virulence of potential vaccine strains of Salmonella typhimurium . A wild virulent strain (3860C), a laboratory strain LT2, and mutants of these 2 strains were evaluated . Inoculation of calf intestinal segments with strain 3860C revealed that fluid responses were greatest in the proximal portion of the small intestine and that doses greater than 10(7) organisms were required to produce fluid responses and mucosal damage . Immunoperoxidase-stained sections of intestine revealed that a large dose of Salmonella organisms was required before mucosal invasion could be detected . Aromatic (aroA), galactose epimerase (galE), and diaminopimelic acid (dap) mutants of strain 3860C all resulted in much less fluid response, mucosal invasion, and mucosal damage compared with those by the parent organism . Strain LT2 induced such weak responses that it was not possible to evaluate reductions in virulence of its mutants . In 6-week-old pigs, there was no fluid response to any strains; however, in 1-week-old pigs, there was fluid response to the wild strain and some of its mutants . In adult rabbits, fluid responses were not observed, except when the wild strain was inoculated in the proximal portion of the small intestine . The calf and 1-week-old pig models appeared to be best suited for assessment of virulence of mutant strains of S typhimurium. Mutat Res, 1987 Mar, 190(3), 191 - 6 Lack of mutagenic activity of bile acids in bacterial fluctuation tests; Venitt S et al.; 3 bile acids (cholic acid, chenodeoxycholic acid and deoxycholic acid) were assayed for mutagenicity in Salmonella typhimurium TA98 and TA100 in fluctuation tests in the absence of an external source of metabolic activation . At the doses tested, there were no dose-related statistically significant increases in mutagenicity compared with appropriate controls . These results do not support the claim (Watabe, J., and H . Bernstein (1985) Mutation Res., 158, 45-51) that these bile acids are mutagenic. Mutat Res, 1987 Mar, 190(3), 177 - 82 Mutagenicity of some substituted 1-phenyl-3,3-dimethyltriazenes . I . The salmonella/mammalian microsome assay and repair test; Cerna M et al.; The mutagenic activity and related biological properties of Br-, Cl-, NO2- and CH3-derivatives of 1-(phenyl)-3,3-dimethyltriazene were investigated in Salmonella/microsome assays with standard and preincubation metabolic activation and in the repair test using Salmonella and E . coli B/r . In the repair test, the CH3-derivative was slightly positive in the E . coli recA and uvrA repair system, the NO2-derivative had a killing effect on Salmonella typhimurium uvrB-deficient strains . In Salmonella mutagenicity assays, all tested triazene derivatives reverted frameshift tester strains, especially TA1537 . The highest number of frameshift mutations was induced by the CH3-derivative in the presence of a standard metabolic activation system; direct mutagenicity of this derivative was weak, reaching about the same level of activity as seen after preincubation . The only test compound that induced mutations of the base-substitution type was the NO2-derivative; this derivative showed the highest mutagenicity when activated by preincubation. Mutat Res, 1987 Mar, 187(3), 133 - 40 Retinol (vitamin A) inhibition of dimethylnitrosamine (DMN) and diethylnitrosamine (DEN) induced sister-chromatid exchanges in V79 cells and mutations in Salmonella/microsome assays; Huang CC; When the Chinese hamster cell line V79 and the tester strain of Salmonella typhimurium TA100 were treated with the precarcinogens dimethylnitrosamine (DMN) or diethylnitrosamine (DEN) in the presence of S9 mix, a dose-dependent increase of sister-chromatid exchanges (SCE) in V79 cells and His+ revertants in TA100 resulted . DMN was a far more efficient SCE inducer than DEN, while DEN was a more efficient inducer of His+ revertants than DMN . Retinol (Rol) effectively inhibited DMN and DEN induced SCE in V79 cells and His+ revertants in TA100 . Concurrent treatment of V79 cells with Rol at various doses and one dose of DMN or DEN in the presence of S9 mix caused a significant reduction of SCE as compared to SCE induced by DMN or DEN without Rol . Rol inhibition of DMN-induced SCE was dose-dependent . Rol was less efficient in inhibiting DEN-induced SCE, and no consistent dose-dependent inhibition was observed . At all doses, Rol significantly inhibited DMN and DEN induced mutation frequencies in TA100 . At the highest dose of Rol (40 micrograms/plate), the inhibition of DMN and DEN induced His+ revertants reached about 90% and 60%, respectively . The possibility that Rol exerts its antimutagenic activities by inhibiting certain forms of the cytochrome P-450 isoenzymes required for activation of precarcinogens such as DMN and DEN is discussed. J Bacteriol, 1987 Mar, 169(3), 1168 - 73 Localization and stoichiometry of hook-associated proteins within Salmonella typhimurium flagella; Ikeda T et al.; The localization of hook-associated proteins (HAP1, HAP2, and HAP3) in Salmonella typhimurium flagella was studied by using specific antibodies together with a second antibody conjugated with colloidal gold . HAP1 and HAP3 were localized at the hook-filament junction, as has been suggested previously . HAP2, however, was localized at the filament tip . This finding supports the idea that HAP2 acts to induce polymerization of endogenous flagellin at the filament tip, and HAP1 and HAP3 are junction proteins to connect hook with filament . Analysis of the protein composition of short flagella from a mutant indicated that a single flagellum contains about 10 to 20 HAP1, 10 to 20 HAP2, and 10 to 40 HAP3 molecules. J Bacteriol, 1987 Mar, 169(3), 1003 - 9 Lysogenic conversion of Salmonella typhimurium bacteriophages A3 and A4 consists of O-acetylation of rhamnose of the repeating unit of the O-antigenic polysaccharide chain; Wollin R et al.; Lysogenization of Salmonella typhimurium with either of the bacteriophages A3 and A4 results in O-acetylation of the L-rhamnose residues of the O-polysaccharide chain of the lipopolysaccharide of the bacterial cell envelope . The O-acetyl group is found on both O-2 and O-3 of the L-rhamnosyl residues . This lysogenic conversion prevents the adsorption of the A3 and A4 phages and also greatly reduces the rate of adsorption of phage P22 to the O-polysaccharide chain as measured by binding studies with whole bacteria . Isolated lipopolysaccharide from A3- and A4-lysogenized bacteria was also inefficient in inactivating these phages: the concentration required for 50% inactivation was 10,000-fold higher than that for lipopolysaccharide from S . typhimurium not lysogenized by any A phage . Binding of phages A3 and A4 is accompanied by hydrolysis of the alpha-1,3 linkage between rhamnose and galactose in the tetrasaccharide repeating unit of the O-polysaccharide . Phage hydrolysis generates saccharides of various lengths, the majority being dodecasaccharides, i.e., equivalent to three repeating units . It is surmised that O-acetylation of the rhamnosyl residue interferes with phage A3, A4, and P22 infection by preventing binding to and hydrolysis of the O-polysaccharide chain, the initial step in the phage infection cycle . The new O-acetyl-rhamnose entities did not elicit specific antibodies in rabbits in accordance with earlier experiences . The O-acetylation of O-2 and O-3 of rhamnose is a new, hitherto unknown, modification of the O-polysaccharide chain of S . typhimurium. Infect Immun, 1987 Mar, 55(3), 816 - 21 Protective immunity induced by outer membrane proteins of Salmonella typhimurium in mice; Udhayakumar V et al.; Outer membrane proteins (OMP) extracted from both smooth (C5) and rough (Rb2) strains of Salmonella typhimurium were able to induce protective immunity to salmonellosis . The OMP-induced protection lasted for at least 6 months . The antibody level was estimated by passive hemagglutination . In the C5 OMP-immunized mice, antibodies to both proteins and lipopolysaccharide were detected . On the other hand, in the Rb2 OMP-immunized mice, antiprotein but not antilipopolysaccharide antibodies were detected . Delayed-type hypersensitivity appeared as early as the second week after immunization with OMP and persisted through the fourth week. J Infect Dis, 1987 Mar, 155(3), 540 - 9 Mediation of serum resistance in Salmonella typhimurium by an 11-kilodalton polypeptide encoded by the cryptic plasmid; Hackett J et al.; A cosmid bank of the DNA (including cryptic plasmid DNA) of a virulent strain of Salmonella typhimurium was prepared in Escherichia coli K12, and clones that contained cryptic plasmid DNA were detected by probing . Two such clones expressed a new outer membrane protein of 11 kilodaltons (kDa) and were serum resistant (E . coli K12 is serum sensitive) . The gene encoding the 11-kDa protein was subcloned in a 2.1-kilobase fragment and shown to mediate serum resistance in both E . coli K12 and a cryptic plasmid-free (serum-sensitive) strain of S . typhimurium . The cryptic plasmid-free S . typhimurium strain did not express normal lipopolysaccharide, but introduction of the 11-kDa protein gene into the strain rendered the strain serum resistant without restoration of normal lipopolysaccharide synthesis . The 11-kDa protein gene was not sufficient to restore either macrophage resistance or virulence to a cryptic plasmid-free strain of S . typhimurium. Cell Biol Toxicol, 1987 Mar, 3(1), 17 - 21 Induction of malignant transformation in vitro and mammary tumors in rats by two new potent anthracycline antitumor antibiotics, morpholinodaunomycin and cyanomorpholinoadriamycin; Westendorf J et al.; The two new potent anthracycline antitumor antibiotics, morpholinodaunomycin and cyanomorpholinoadriamycin, are non-mutagenic or weakly mutagenic in Salmonella typhimurium or V79 Chinese hamster cells, but highly active inducing DNA repair in in cultured rat hepatocytes . Both agents were found to induce malignant transformation in vitro of C3H M2 mouse fibroblasts and mammary tumors in female Sprague-Dawley rats . The data indicate a) that these new anthracyclines, too, are highly oncogenic and b) in conjunction with previously published results, that the predictive value of in vitro short-term tests for in vivo carcinogenicity is dependent on the employment of a battery of such tests. Microb Pathog, 1987 Mar, 2(3), 211 - 21 Salmonella typhimurium aroA mutants as carriers of the Escherichia coli heat-labile enterotoxin B subunit to the murine secretory and systemic immune systems; Maskell DJ et al.; We investigated the ability of Salmonella typhimurium vaccines to deliver heterologous antigens to the systemic and secretory immune systems of the mouse, while retaining their immunogenicity against salmonellosis . S . typhimurium SL3261, an avirulent aroA mutant, or SL3261 carrying plasmid pBRD026, a pBR322 derivative encoding the gene for Escherichia coli LT-B were used to immunize BALB/c mice orally . Both immunizing strains invaded the mononuclear phagocyte system of the mice, grew slowly until approximately day 14 post-infection, and then were rapidly cleared . No salmonellae were detected in livers, spleens, mesenteric lymph nodes or Peyer's patches by day 42 . Mice immunized with either strain and challenged orally with the virulent parent strain, SL1344, several weeks after clearing the immunizing organism, were protected against the lethal S . typhimurium infection . Mice infected with SL3261 (pBRD026) developed substantial levels of IgG and IgA anti-LT-B antibodies 14 days post-infection in both serum and gut samples . The sera neutralized the effects of LT in an in vitro Vero cell assay . Thus, aroA mutants of S . typhimurium can deliver a heterologous antigen from a different enteric pathogen to the murine systemic and secretory immune systems without altering their efficacy against salmonellosis. Mutagenesis, 1987 Mar, 2(2), 97 - 9 Synthesis and mutagenicity of 3-halogenated and 3,3',5,5'-tetrahalogenated benzidines; Savard S et al.; 3-Fluorobenzidine (FBz), 3-chlorobenzidine (ClBz), 3-bromobenzidine (BrBz), 3,3',5,5'-tetrafluorobenzidine (F4Bz), and 3,3',5,5'-tetrachlorobenzidine (Cl4Bz) were synthesized and tested for their ability to revert Salmonella typhimurium . F4Bz was the only compound to show direct-acting mutagenicity and was equally potent in strain TA98 and the acetylase-deficient strain TA98/1,8-DNP6 . In the presence of hamster liver S9, all compounds except Cl4Bz were mutagenic . The relative mutagenicities in TA98 were FBz greater than ClBz greater than BrBz greater than F4Bz greater than Bz greater than Cl4Bz = 0 . In TA98/1,8-DNP6 the trend was F4Bz approximately BrBz approximately ClBz greater than FBz greater than Bz greater than Cl4Bz = 0. Mutagenesis, 1987 Mar, 2(2), 137 - 40 Activation of 2-amino-3-methylimidazo (4,5-f) quinoline in rat and human hepatocyte/Salmonella mutagenicity assays: the contribution of hepatic conjugation; Paterson P et al.; The capacity of human liver S9 and hepatocytes to metabolically activate 2-amino-3-methylimidazo (4,5-f) quinoline (IQ) in Salmonella mutagenicity assays more closely resembles that of preparations from Aroclor-induced rat than control rat . The extent to which hepatocyte conjugating enzymes contribute to activation in these assays has been studied . Omission of sulphate or addition of a 'specific' sulphotransferase inhibitor (2,6-DCNP) did not significantly reduce mutagenicity, nor did PAPS enhance S9-mediated bacterial mutagenicity . Conversely, mutagenicity was significantly inhibited by PCP (an inhibitor of both sulphotransferase and acetyltransferase) and an acetylation-deficient Salmonella (TA98/1,8DNP6) was unresponsive to the mutagenicity of IQ . These data suggest that acetylation but not sulphation is important in IQ bacterial mutagenesis . The addition of acetyl CoA, PAPS-generating system or ATP paradoxically reduces the mutagenicity of IQ in S9/Salmonella TA98 assays . Therefore, activation by esterification in hepatocytes does not contribute to the mutagenicity of IQ in Salmonella typhimurium possibly due to restricted access of conjugates into the bacterial cell. Mutagenesis, 1987 Mar, 2(2), 101 - 5 Synthesis and bacterial mutagenicity of the cyclopenta oxides of the four cyclopenta-fused isomers of benzanthracene; Bartczak AW et al.; Many polycyclic aromatic hydrocarbons containing peripherally fused cyclopenta rings are believed to be activated primarily by epoxidation of the cyclopenta ring . The cyclopenta epoxides of a series of four cyclopenta benzanthracene derivatives, benz{e}aceanthrylene-5,6-oxide, benz{j}aceanthrylene-1,2-oxide, benz{l}aceanthrylene-1,2-oxide and benz{k}acephenaceanthrylene-4,5-oxide were synthesized from their parent hydrocarbons by formation of the bromohydrin followed by dehydrobromination, and characterized by u.v.-vis, and 1H n.m.r . spectroscopy and mass spectrometry . The mutagenicity of these compounds was investigated in the Ames plate incorporation assay with Salmonella typhimurium strain TA98 . All the oxides were active without exogenous metabolic activation (170-320 His+ revertants per nanomole) and also toxic above 0.5 microgram/plate . Addition of S9 protein did not increase, and generally decreased, the mutagenicity of the oxides, while toxicity was largely unchanged . These results are consistent with the postulated role of cyclopenta oxides as major contributors to the mutagenicity of the parent compounds in the Ames assay. J Gen Microbiol, 1987 Mar, 133 ( Pt 3), 779 - 82 Flagellation of Salmonella typhimurium treated with nalidixic acid; Iino T et al.; Filamentous cells of Salmonella typhimurium, obtained after treatment with nalidixic acid in the exponential phase of growth, elongated up to 10 micron, corresponding to 4 unit cell lengths, per nucleoid . During elongation, division of nucleoids and septum formation did not occur, but de novo formation of flagella continued . Most of the filamentous cells were motile, and flagella were evenly distributed on their surface. J Gen Microbiol, 1987 Mar, 133 ( Pt 3), 515 - 25 L-cysteine biosynthesis in Escherichia coli: nucleotide sequence and expression of the serine acetyltransferase (cysE) gene from the wild-type and a cysteine-excreting mutant; Denk D et al.; Serine acetyltransferase (SAT) from Escherichia coli is subject to feedback inhibition by L-cysteine . A mutant was isolated which excretes L-cysteine because of a lesion in cysE, the structural gene for SAT, rendering the enzyme less feedback sensitive . To analyse the structural basis for this mutation the cysE genes both from wild-type E . coli and the mutant strain were cloned and their nucleotide sequences determined . The cysE gene contained an open reading frame consisting of 819 bp, equivalent to a protein of 273 amino acids . The mutant gene showed a single base change in position 767 resulting in a methionine to isoleucine substitution . A causal connection between this SAT sequence alteration, feedback insensitivity and L-cysteine excretion was demonstrated . The SAT from the wild-type strain was purified . It was composed of a single polypeptide chain migrating in SDS gels according to an Mr of 34,000 . As in Salmonella typhimurium, the enzyme was associated in a bifunctional complex with O-acetylserine (thiol)-lyase. Tsitol Genet, 1987 Mar-Apr, 21(2), 118 - 22 {Modifying action of drug preparations on the effect of promutagen compounds}; Oblapenko NG et al.; The Ames test has shown that the action of nitrosomorpholine and cyclophosphane promutagens on bacteria of Salmonella typhimurium TA 1950 increases while using S-9 liver fraction of rats treated with pharmaceuticals of amidopyrine, reserpine and pyrazidol and decreases while using those treated with phenazepam. Res Vet Sci, 1987 Mar, 42(2), 194 - 9 Observations on the pathogenesis of experimental Salmonella typhimurium infection in chickens; Barrow PA et al.; The virulence of Salmonella typhimurium strains for day-old chickens was examined . The mortality following oral inoculation varied from 0 to 100 per cent . Some breeds were more susceptible than others . There was no correlation between oral and parenteral virulence . Pathogenesis studies associated with one of the most virulent strains suggested that, after invasion, organisms multiplied in the liver and spleen and spread to other organs producing a systemic infection . The cause of death was probably a combination of anorexia and dehydration resulting from general malaise and diarrhoea . A virulent strain studied in detail spread through the body faster, persisted for a longer period and was more invasive than an avirulent strain . In the system studied invasiveness was the virulence determinant of overriding importance. Cell Biol Toxicol, 1987 Mar, 3(1), 51 - 61 Mutagenic activation of 2-amino-3-methylimidazo{4,5-f}-quinoline (IQ) and 2-amino-3,4-dimethylimidazo{4,5-f}-quinoline (MeIQ) by subcellular fractions and cells isolated from small intestine, kidney and liver of the rat; Holme JA et al.; The mutagenic activity of the pyrolysis products 2-amino-3-methyl-imidazo{4,5-f}-quinoline 2-amino-3,4-dimethylimidazo{4,5-f}-quinoline in Salmonella typhimurium TA98 using rat intestinal and renal subcellular fractions as activation systems was approximately 1 and 5 revertants per nmol, respectively . This was 1,000 times less than the activity with a subcellular fraction from rat liver . The mutagenic activity of both compounds was considerably increased using intestinal, renal and hepatic preparations isolated from PCB (Aroclor 1254)-pretreated rats, compared to preparations from control animals . In addition, both compounds displayed a moderate direct-acting mutagenic activity at concentrations above 10(-5) M . Isolated cells from small intestine, kidney and liver incubated in nucleopore chambers were able to convert both compounds into products which mutated bacteria outside the chambers . The concentrations of chemicals required to yield responses of a similar magnitude were approximately 3 orders of magnitude higher in the intestinal and renal systems compared to the hepatic system . The formation of metabolites mutagenic for Salmonella typhimurium by hepatic subcellular and cellular systems was shown to be superior to the respective intestinal and renal systems. Parasite Immunol, 1987 Mar, 9(2), 151 - 60 Live oral Salmonella vaccines: potential use of attenuated strains as carriers of heterologous antigens to the immune system; Dougan G et al.; Live attenuated strains of salmonellae are showing promise as live oral vaccines against human typhoid fever and other Salmonella infections of man and animals . Attenuation can be achieved by introducing genetically defined, non-reverting mutations into specific genes on the Salmonella chromosome . Mutations in the gal E or aroA genes of Salmonella inhibit the ability of the bacteria to grow in vivo, and strains carrying such lesions are effective vaccines against salmonellosis . Genetic determinants encoding for the expression of potentially protective antigens from heterologous, non-Salmonella pathogens can be readily introduced into these attenuated Salmonella strains . Expression of the heterologous antigen does not affect the ability of the Salmonella host to be used as a Salmonella vaccine . Mice infected orally with a Salmonella typhimurium aroA vaccine expressing the Escherichia coli heat-labile toxin B subunit developed both a secretory and serum antibody response to this antigen . These serum antibodies were able to neutralise the activity of E . coli heat-labile toxin in tissue culture assays . A humoral and cell-mediated (DTH) immune response was detected against beta galactosidase, an intracellular antigen, in mice infected with an aroA vaccine expressing this cloned antigen . The prospects for the development of live Salmonella vaccines as a method for delivering heterologous antigens derived from bacteria, viruses and parasites is discussed. Infect Immun, 1987 Mar, 55(3), 822 - 4 An outer membrane protein (porin) as an eliciting antigen for delayed-type hypersensitivity in murine salmonellosis; Udhayakumar V et al.; The porin, an outer membrane protein of Salmonella typhimurium, was found to be a suitable antigen for eliciting delayed-type hypersensitivity in mouse salmonellosis . Histological examination of the reaction site revealed that the porin was superior to other antigenic preparations in eliciting a typical delayed-type hypersensitivity reaction consisting of mononuclear cell infiltration without polymorphonuclear cell contamination . This study indicates the importance of using a suitable protein antigen from S . typhi for human application. Mutagenesis, 1987 Mar, 2(2), 115 - 9 Circadian monitoring of gastric juice mutagenicity; De Flora S et al.; The circadian monitoring of intragastric pH and of the mutagenicity of 440 gastric juice samples collected hourly from 22 subjects provided evidence that, irrespective of diagnosis and treatment, a weak yet consistent increase in revertants can be detected in his- Salmonella typhimurium strains during the 3-4-h periods following each meal . The recorded mutagenic activity was not related to the histidine content of gastric juice, was due to thermostable components and was not significantly inhibited by administration of vitamin C . Various genetic mechanisms were involved, which were different from those consequent to the artificial supplementation of gastric juice with sodium nitrite . Treatment with a histamine H2-receptor antagonist (famotidine), either at dinner or at bedtime, was followed by a nocturnal plateau of mutagenicity . However, such effect was not due to mutagenicity of the drug or of its derivatives, but to the therapeutic rise in pH associated with its antisecretory activity. Mutat Res, 1987 Mar, 177(1), 45 - 52 Glutathione mutagenesis in Salmonella typhimurium TA100: dependence on a single enzyme, gamma-glutamyltranspeptidase; Stark AA et al.; Glutathione was mutagenic in Salmonella typhimurium strain TA100 in the presence of purified mammalian gamma-glutamyltranspeptidase . Glutathione disulfide, gamma-glutamyl glutamic acid, and S-methyl-glutathione were not mutagenic under the same conditions . Glutathione-mediated, gamma-glutamyltranspeptidase-dependent mutagenesis of TA100 cells was inhibited by serine-borate complex, a known gamma-glutamyltranspeptidase inhibitor, and potentiated by glycylglycine, a known gamma-glutamyltranspeptidase enhancer . It is concluded that this enzyme is necessary and sufficient to activate glutathione to a mutagen. Mutat Res, 1987 Mar, 177(1), 35 - 43 Formation of a highly mutagenic diazo compound from the bamethan-nitrite reaction; Kikugawa K et al.; A variety of cardiovascular drugs were treated with 10 equivalent amounts of nitrite in acidic solutions . Among 18 drugs, a preparation of bamethan {1-(4-hydroxyphenyl)-1-hydroxy-2-butylaminoethane} showed strikingly high mutagenicity by this treatment toward Salmonella typhimurium TA98 and TA100 strains . Treatment of bamethan with an equivalent amount of nitrite gave N-nitrosobamethan I which was not mutagenic . However, treatment of bamethan with 4 equivalent amounts of nitrite afforded a highly mutagenic compound II, which was identified as 3-diazo-N-nitrosobamethan by its physicochemical analysis and chemical properties . Specific mutagenic activity of II was 9200 His+ revertants/mu mole toward TA98 and 8060 His+ revertants/mu mole toward TA100 . Addition of microsomal system little affected the activity . Bamethan is administrated orally during long period for treatment of cardiovascular diseases . It is noted that this drug can produce the highly mutagenic diazo compound by reaction with nitrite which is present in digestive tracts. Microb Pathog, 1987 Mar, 2(3), 171 - 83 Role of monoclonal O-antigen antibody epitope specificity and isotype in protection against experimental mouse typhoid; Carlin NI et al.; A panel of 14 monoclonal antibodies with specificity for the O-antigenic polysaccharide chain of the lipopolysaccharide of the cell envelope of Salmonella typhimurium was established . The specificity of each antibody clone was determined against a set of Salmonella saccharide antigens, natural and synthetic, in passive hemagglutination and enzyme immunoassays . The monoclonal antibodies could be classified into at least five different groups: (i) O4 epitope specific, (ii) O4,12 specific, (iii) O4,12(2) specific, (iv) O5 specific, and (v) O12 specific . These specificities correspond to different structural and conformational domains of the polysaccharide chain, and often extend over more than one repeating unit (tetrasaccharide) of the polymer . The passive protection afforded by these antibodies was estimated in an experimental mouse typhoid model using S . typhimurium SH2201 for intraperitoneal challenge . Monoclonal antibodies of the IgG3 isotype were available for four of the epitope groups and were protective in the following order of activity O4 greater than O4,12 greater than O4,12(2) greater than or equal to O12 . The difference between O4 and 012 antibodies was greater than 2500 fold in protective activity . Antibodies of the IgM class were highly protective irrespective of being of the O4,12 or O12 epitope specificity . Two IgA antibodies with O5 epitope specificity were not protective . The results show that both isotype and epitope specificity can be of importance for the protective ability of antibodies generated by the host. Eur J Biochem, 1987 Feb 16, 163(1), 51 - 5 Reversible binding of Salmonella typhimurium lipopolysaccharides by immobilized protamine; Helander IM et al.; The ability of agarose-linked protamine to bind Salmonella typhimurium lipopolysaccharides was investigated . Radioactively labelled lipopolysaccharides were isolated both from a smooth strain (SH6749, labelled with {14C}galactose) and from a rough strain (SH5014, lipopolysaccharide chemotype Rb2, labelled with {3H}acetate) . From 50-micrograms samples of the lipopolysaccharides, protamine-agarose columns bound 99.5-99.9% of the input radioactivity . The binding efficacy was not affected by pH in the range from 3.7 to 10.5 . Maximal binding capacity of protamine-agarose for highly soluble (triethylamine form) lipopolysaccharide of SH5014 was estimated to be 13.5 mg/ml packed adsorbent . The bound lipopolysaccharides could be totally released from the columns and recovered by elution with the anionic detergent sodium deoxycholate, or with 0.5 M NaCl in the presence of the uncharged detergent Triton X-100 . By analysis in sodium dodecyl sulfate/polyacrylamide gels, the macromolecular quality of the recovered lipopolysaccharide was shown to be identical to that of the original . Protamine-agarose chromatography can thus be applied to purify lipopolysaccharide preparations, and to separate as well as concentrate lipopolysaccharides from dilute solutions without altering their composition . This application was challenged with water as well as insulin solution experimentally contaminated with radiolabelled lipopolysaccharide . While the insulin protein did not bind to the protamine-agarose, the contaminating lipopolysaccharide was effectively trapped. Toxicol Lett, 1987 Feb, 35(2-3), 201 - 7 Mutagenicity of the C-nitroso analog of fenitrothion; Corbett MD et al.; The chemicals fenitrothion, nitroso fenitrothion, amino fenitrothion and 3-methyl-4-nitrophenol were tested for mutagenicity to Salmonella typhimurium strains TA98 and TA100, both in the presence and absence of rat liver S-9 mix . The strong mutagenicity of nitroso fenitrothion to both strains either in the presence or absence of S-9 mix contrasted with the observation that fenitrothion displayed no mutagenicity in these tester strains . The results suggest that the normal nitroreductases present in TA98 and TA100 cannot metabolize fenitrothion to a mutagenic metabolite . This inability of the tester strains to effect partial nitroreduction results in the failure of this screening system to predict the potential genotoxicity of this pesticide. J Clin Microbiol, 1987 Feb, 25(2), 273 - 7 Enzyme-linked immunosorbent assay for detection of Salmonella typhi protein antigen; Appassakij H et al.; A double-antibody sandwich enzyme-linked immunosorbent assay (ELISA) was designed for the detection of Salmonella typhi protein antigen . The optimal concentration of antibody for coating the plate was found to be 50 micrograms/ml . The optimum conditions for antibody coating and antigen and conjugate incubation were 37 degrees C for 3 h, 37 degrees C for 2 h, and 4 degrees C overnight, respectively . The enzyme-substrate reaction was allowed to take place at 30 degrees C for 1 h . The established ELISA was found to be reproducible, with an inter-run coefficient of variation of less than 12% for the detection of an S . typhi protein antigen concentration of 0.5 to 50 micrograms/ml . The minimal detectable level of the antigen was 0.5 micrograms/ml . Cross-reactions were observed with the high level (50 micrograms/ml) of protein antigens obtained from Salmonella typhimurium, Escherichia coli, Salmonella paratyphi A, and Salmonella enteritidis . The ELISA established was used for the detection of S . typhi protein antigen in serum from 62 patients with typhoid, 30 patients with clinically diagnosed typhoid fever, 21 patients with paratyphoid, 17 patients with pyrexia caused by other bacteria, and 160 normal, healthy individuals . It was found that the sensitivity, specificity, accuracy, positive predictive value, and negative predictive value of this assay were 83.87, 89.04, 87.93, 67.53, and 95.31%, respectively. Infect Immun, 1987 Feb, 55(2), 467 - 71 Susceptibilities of macrophage populations to infection in vitro by Leishmania donovani; Olivier M et al.; Many studies have demonstrated differences in the resistance of strains of mice to infection by Leishmania donovani, Salmonella typhimurium, and Mycobacterium bovis BCG; this resistance/susceptibility phenotype seems to be controlled by a single gene . The present study investigated the susceptibility of liver, lung, peritoneal, and spleen macrophages to infection by L . donovani promastigotes in vitro; the objective was to determine if the susceptibility of animals was expressed by their macrophages when infected in vitro . This study indicated that the Lsh phenotype was only expressed by liver macrophages . The liver macrophages of the susceptible C57BL/6J strain were significantly more phagocytic than those of the resistant C57L/J strain; infection affected the phagocytic activity of the macrophage population . These results indicated that only liver macrophages can express the Lsh gene . Recognition of expression is in part due to its effect on the phagocytic activity of the macrophages. Agents Actions, 1987 Feb, 20(1-2), 93 - 7 The inhibition by morphine and D-aspartic acid of antibody production against Salmonella typhimurium antigen in rats: its antagonism by L-aspartic acid; Koyuncouglu H et al.; The changes in the production of antibody against Salmonella typhimurium antigen were investigated in rats by means of the agglutination test after chronic oral administration of the L-asparaginase inhibitors morphine (M) or D-aspartic acid (D-Asp) alone or together with L-aspartic acid (L-Asp) and food restriction, all of which had been started five days before the injections of antigen . The statistical evaluation, carried out after the titers had been defined as -log2 of the highest dilution giving a positive agglutination reaction, showed that M or D-Asp significantly decreased antibody production in comparison with the immunized control or food restricted group . The concomitant administration of L-Asp appeared to significantly antagonize the inhibitory effect of both M and D-Asp . Therefore, the results were considered as further supporting evidence for the fact that the deleterious effect of M on the immune system and its functions might be related to the inhibitory effect of M on L-asparaginase activity. J Appl Bacteriol, 1987 Feb, 62(2), 115 - 8 A note on the effect of the lactoperoxidase systems on salmonellas in vitro and in vivo; Wray C et al.; The lactoperoxidase system (LPS), a natural bactericidal system in milk, was investigated for its activity against salmonellas in vivo and in vitro . In acidified raw milk, in which the LPS was supplemented with an exogenous supply of H2O2, the numbers of salmonellas decreased rapidly . Different salmonella serotypes were affected to the same extent; rough strains, however, were more susceptible than smooth strains . When calves were fed on fresh milk, containing the LPS, and challenged with Salmonella typhimurium in doses of either 10(9) or 10(10), the clinical findings and salmonella excretion patterns were similar to those of control calves fed on heated milk . It was concluded that further studies, perhaps in the field, are necessary to evaluate LPS as a possible non-antibiotic system to control salmonellosis. J Steroid Biochem, 1987 Feb, 26(2), 259 - 64 Sterol hydroperoxide metabolism by Salmonella typhimurium; Smith LL et al.; In order to rationalize multiphasic dose-response data evincing mutagenicity towards Salmonella typhimurium TA1537 for sterol hydroperoxides 3 beta-hydroxy-5 alpha-cholest-6-ene-5-hydroperoxide and 3 beta-hydroxycholest-5-ene-7 alpha-hydroperoxide their metabolism by the bacterial test strain was investigated . The 5 alpha-hydroperoxide was isomerized to the 7 alpha-hydroperoxide and reduced to 5 alpha-cholest-6-ene-3 beta,5-diol; the 7 alpha-hydroperoxide was reduced to cholest-5-ene-3 beta,7 alpha-diol and transformed to 3 beta-hydroxycholest-5-en-7-one . The 3 beta,5 alpha-diol and 3 beta,7 alpha-diol were not interconverted nor was either transformed to the 7-ketone. Mutat Res, 1987 Feb, 190(2), 113 - 7 2,7-Diamino-3,8-dimethylphenazine as the major mutagenic product from the reaction of 2,4-diaminotoluene with hydrogen peroxide; Watanabe T et al.; The mutagenicity of 2,4-diaminotoluene (DAT) in Ames's Salmonella/microsome test was remarkably enhanced by treatment with hydrogen peroxide . Therefore, identification of the major mutagenic reaction product of 2,4-DAT with hydrogen peroxide at room temperature has been performed . Red precipitates were produced in a 2-day reaction mixture and were column chromatographed on silica gel . 5 fractions having mutagenic potency were obtained . The red crystalline needles, obtained as the major reaction product, were separated from fraction 2 and were subjected to high resolution mass spectrometry, 1H- and 13C-NMR spectrometry . The structure of the compound was determined to be 2,7-diamino-3,8-dimethylphenazine from physicochemical and chemical evidence . The compound induced 212 revertants/nmole in Salmonella typhimurium TA98 with 25 microliters S9 per plate. Mutat Res, 1987 Feb, 190(2), 107 - 12 Enhancement of the mutagenicity of 2-acetylaminofluorene by flavonoids and the structural requirements; Ogawa S et al.; The enhancing effects of 12 kinds of flavonoids on the mutagenicity of 2-acetylaminofluorene (AAF) in Salmonella typhimurium TA98 were investigated . In the mixed applications of AAF (22.4 nmoles/plate) with flavonoids (31.4-45.0 nmoles/plate) in the presence of a mammalian metabolic activation system (S9 mix), morin, galangin, flavonol, kaempferol, quercetin and myricetin enhanced the mutagenicity of AAF by 3.3-10.2-fold . The potency of the mutagenicity enhancing effects increased in the described order . For the mutagenicity-enhancing effects of the flavonoids on AAF, the flavonol structure, including the free 3-hydroxyl group and the 2,3-double bond, were essential . In the quercetin analogues, the 5-hydroxyl group was also essential . Further, the numbers of the hydroxyl groups substituted at the 3', 4' and 5'-positions in the B-ring contributed to an increase of the enhancing effect, whereas the substitution of a hydroxyl group at the 2'-position depressed the potency of the effect. Mutat Res, 1987 Feb, 190(2), 101 - 5 Selenium inhibition of benzo{a}pyrene, 3-methylcholanthrene, and 3-methylcholanthrylene mutagenicity in Salmonella typhimurium strains TA98 and TA100; Prasanna P et al.; Selenium (Se) decreased the mutagenicity of benzo{a}pyrene (BP), 3-methylcholanthrene (3MC), and 3-methylcholanthrylene (3MCE) in Salmonella typhimurium strains TA98 and TA100 . Metabolism of BP, 3MC and 3MCE to mutagens was accomplished with the liver S9 fraction from Aroclor 1254-treated male Sprague-Dawley rats . Exposure of the bacteria to 4 nmoles BP, 10 nmoles 3MC, or 10 nmoles 3MCE in the presence of S9, and up to 200 nmoles Se as Na2SeO3 resulted in decreased mutagenicities up to 39, 66 and 60% of their respective control activities without Se in TA98 and up to 46, 52 and 64% of their respective control activities without Se in TA100 . Se (200 nmoles) alone was not mutagenic in strains TA98 or TA100 with or without S9 . BP, 3MC and 3MCE were not mutagenic in either strain without S9 . None of the tested concentrations of BP, 3MC, 3MCE and Se were cytotoxic . Assays of the aryl hydrocarbon hydroxylase (AHH) activity in the S9 preparation revealed decreased AHH activity with increase in Se concentration . The decreased mutagenicity and AHH activity were Se (as Na2SeO3) dependent and could not be duplicated by sulfur (S as Na2SO3) . Inhibition of AHH activity by Se provides an explanation of the mechanism of Se inhibition of BP, 3MC and 3MCE mutagenicities in S . typhimurium TA98 and TA100. Mutat Res, 1987 Feb, 187(2), 67 - 77 Mutagenic activity of nitro-substituted cyclopenta-fused polycyclic aromatic hydrocarbons towards Salmonella typhimurium; Goldring JM et al.; Cyclopenta-fused isomers of pyrene and benz{a}anthracene, nitrated on the etheno bridge, were synthesized and tested in the Ames plate-incorporation assay . Since enzymatic reduction, if it occurs in these compounds, would form arylhydroxylamines which in turn would form highly stabilized arylnitrenium ions, we hoped to test the hypothesis that the direct-acting mutagenic activity of nitroPAH is correlated with the degree of stabilization of the electrophilic intermediate . We found that these compounds are mutagenic (1-9 rev/nmole in Salmonella typhimurium TA98) and do not require S9 activation . However, this activity is substantially lower than that of other nitroPAH of comparable size such as 1-nitropyrene (250-300 rev/nmole) . The reasons for this comparative lack of activity are discussed with reference to current theories regarding structure-activity relationships of nitroPAH. Mutat Res, 1987 Feb, 182(1), 5 - 13 Induction of genetic tandem duplications in Salmonella by polycyclic aromatic hydrocarbon and amine carcinogens; Pall ML et al.; 6 polycyclic aromatic hydrocarbon or similar amine carcinogens were tested as inducers of genetic tandem duplications in a rough strain of Salmonella typhimurium . When metabolically activated by rat-liver microsomes, all 6 were active in inducing genetic tandem duplications, yielding from over 3 times to almost 14 times as many tandem duplicants per viable bacterium as did concurrent uninduced control cultures . These results extend the number and chemical diversity of carcinogens shown to induce genetic duplications in bacterial tester systems . We suggest that polycyclic hydrocarbon carcinogens may act in carcinogenesis by inducing genetic duplications or other genetic rearrangements . Duplication induction may be a useful genetic endpoint for screening potential carcinogens. Mutat Res, 1987 Feb, 176(2), 185 - 98 Comparative mutagenicity of halogenated pyridines in the Salmonella typhimurium/mammalian microsome test; Claxton LD et al.; The Salmonella/microsome assay with strains TA97, TA98, TA100 and TA102 was used to examine the potential mutagenicity and structure-activity of 16 mono- and di-halogenated pyridines . The chemical reactivity of the halopyridines suggests that nucleophilic displacement of halogens can occur with halogens at positions 2, 4 and 6 being displaced in addition-elimination reactions . 2-Chloropyridine gave a positive result with rat-liver metabolic activation, and 2-fluoropyridine gave equivocal results under these conditions . Mutagenic responses were also obtained with 2-chloromethyl pyridine and 3-chloromethyl pyridine, in both the presence and absence of rat-liver S9 . These results suggest that the halogenated pyridines, especially with halogens at the 2-position, and singly on a methyl substituent, have mutagenic activity in the Salmonella assay. Mutat Res, 1987 Feb, 176(2), 171 - 8 Mutagenicity of halogenated and other substituted dinitrobenzenes in Salmonella typhimurium TA100 and derivatives deficient in glutathione (TA100/GSH-) and nitroreductase (TA100NR); Kerklaan PR et al.; In a previous study, it was shown that 1-chloro-2,4-dinitrobenzene (CDNB) was less mutagenic in a glutathione (GSH)-deficient derivative of Salmonella typhimurium TA100 (TA100/GSH-) than in TA100 itself, suggesting that the mutagenicity of the compound is dependent on GSH, possibly mediated by the action of a bacterial nitroreductase(s) on the CDNB-GSH conjugate . In the present study a series of mutagenicity tests were performed to determine how CDNB could be activated after reaction with GSH . In liquid preincubation assays, strains TA100, TA100/GSH- and TA100NR, a nitroreductase-deficient derivative of TA100, were treated with CDNB and its fluoro and bromo analogues (FDNB and BDNB), further with its GSH conjugate (S-GSH-DNB) and possible metabolic products, such as S-cysteine-dinitrobenzene (S-Cys-DNB) and S-methyl-dinitrobenzene (S-methyl-DNB), and with 2 more analogues, O-methyl-dinitrobenzene (O-methyl-DNB) and dinitrobenzene (DNB) . CDNB, FDNB and BDNB were found to be mutagenic in TA100 and TA100NR, while TA100/GSH- was much less sensitive to the mutagenic action of these halogenated dinitrobenzenes . DNB, O-methyl-DNB, S-methyl-DNB and S-Cys-DNB induced equal numbers of His+ revertants in TA100 and TA100/GSH-, but were not mutagenic in TA100NR . S-GSH-DNB showed no mutagenic activity in any of the 3 strains under the present experimental conditions . These results suggest that the halogenated aromatics may react with bacterial DNA and produce pre-mutagenic alterations according to 2 mechanisms: direct attack on the DNA through nucleophilic substitution (SN2) of the halogen atoms; activation through GSH conjugation and subsequent nitroreduction of the conjugate or its metabolic products to more reactive intermediates. J Virol, 1987 Feb, 61(2), 594 - 6 The genome of lipid-containing bacteriophage PRD1, which infects gram-negative bacteria, contains long, inverted terminal repeats; Gerendasy DD et al.; The bacteriophage PRD1 is a lipid-bearing phage that infects a wide variety of gram-negative bacteria, including Escherichia coli and Salmonella typhimurium when they contain the appropriate plasmid . It contains a linear duplex DNA molecule that is covalently bound by its 5' ends to a terminal protein . We report here that the PRD1 genome contains a 111-base-pair terminal inverted repeat which does not bear homology to that of any known linear duplex DNAs with terminal proteins . We further report that its 3' termini are susceptible to enzymatic digestion by exonuclease III. J Bacteriol, 1987 Feb, 169(2), 917 - 9 Acetohydroxy acid synthase I is required for isoleucine and valine biosynthesis by Salmonella typhimurium LT2 during growth on acetate or long-chain fatty acids; Dailey FE et al.; Salmonella typhimurium LT2 normally expresses two acetohydroxy acid synthases (AHAS I and AHAS II) . The function of AHAS I in this organism was unclear, since AHAS I-deficient (ilvBN) mutants of LT2 grew well on glucose or succinate minimal media, whereas AHAS II-deficient (ilvGM) mutants requried isoleucine for normal growth on glucose minimal media . We report that AHAS I-deficient mutants of S . typhimurium required isoleucine and valine for growth on acetate or oleate minimal media, whereas AHAS II-deficient mutants were able to grow on these media without isoleucine supplementation. J Bacteriol, 1987 Feb, 169(2), 897 - 9 Evidence for regulation of gluconeogenesis by the fructose phosphotransferase system in Salmonella typhimurium; Chin AM et al.; A genetic locus designated fruR, previously mapped to min 3 on the Salmonella typhimurium chromosome, gave rise to constitutive expression of the fructose (fru) regulon and pleiotropically prevented growth on all Krebs cycle intermediates . Regulatory effects of fruR were independent of cyclic AMP and its receptor protein and did not prevent uptake of Krebs cycle intermediates . Instead, the phosphotransferase system appeared to regulate gluconeogenesis by controlling the activities of phosphoenolpyruvate carboxykinase and phosphoenolpyruvate synthase. J Bacteriol, 1987 Feb, 169(2), 894 - 6 Genetic expression of enzyme I activity of the phosphoenolpyruvate:sugar phosphotransferase system in ptsHI deletion strains of Salmonella typhimurium; Chin AM et al.; Mutants expressing a novel enzyme I of the phosphoenolpyruvate:sugar phosphotransferase system, termed enzyme I, were isolated from strains of Salmonella typhimurium which were deleted for the HPr and enzyme I structural genes . The mutations lay in a newly defined gene, termed ptsJ, which mapped on the S . typhimurium chromosome between the ptsHI operon and the cysA gene. Environ Res, 1987 Feb, 42(1), 106 - 13 In vivo induction of sister chromatid exchanges in mice by nitrosated coal dust extract; Krishna G et al.; The genotoxicity of coal dust extract nitrosated with sodium nitrite (NaNO2) was investigated in mice with the in vivo sister chromatid exchange (SCE) assay system . The SCEs in bone marrow cells of mice were examined following single and double oral dosings of coal dust extract, NaNO2, and nitrosated coal dust extract . Coal dust extract and NaNO2 separately did not cause significant increases of SCEs either in single or in double dosings . Nitrosated coal dust extract in single doses did not increase SCEs but in two doses significant increases in SCEs were observed (P less than 0.02) . The mutagenicity of the same extracts was tested in Salmonella typhimurium with the Ames tester strain TA98 . Coal dust extract was either non- or weakly mutagenic and NaNO2 was nonmutagenic . The nitrosated coal dust extract caused pronouced increases in his+ revertants both with and without rat liver S9 activation . These findings provide additional evidence that nitrosation of ingested coal dust which may occur in the stomach environment could be one of the factors leading to the higher incidence of gastric cancer in coal miners. J Gen Microbiol, 1987 Feb, 133 ( Pt 2), 305 - 10 The osmotically regulated proU locus of Salmonella typhimurium encodes a periplasmic betaine-binding protein; Higgins CF et al.; The proU locus of Salmonella typhimurium encodes an osmotically induced betaine transport system . We have identified a 31 kDa periplasmic protein, encoded by proU, whose synthesis is induced by osmotic stress . A specific betaine-binding activity with a KD of about 1 microM is also present in the periplasm of osmotically induced cells . This activity is absent in those proU mutants which lack the 31 kDa periplasmic protein . Thus, ProU is a periplasmic binding-protein-dependent transport system. J Interferon Res, 1987 Feb, 7(1), 121 - 9 Interferon-gamma potentiation of lipopolysaccharide-induced eicosanoid release from human monocytes; Nichols FC et al.; Interferon-gamma (IFN-gamma) can act to potentiate lipopolysaccharide (LPS)-stimulated processes in mononuclear phagocytes, including interleukin-1 release and tumoricidal activity . The present investigation examined the capacity of IFN-gamma to modulate LPS-stimulated prostaglandin E2 (PGE2) and thromboxane B2 (TxB2) release from counterflow isolated human monocytes . The release of PGE2 and TxB2 was compared for cells incubated with IFN-gamma prior to treatment with LPS and for cells treated simultaneously with IFN-gamma and LPS . Treatment of cells with IFN-gamma prior to stimulation with LPS (10 micrograms/ml, Salmonella typhimurium) resulted in elevated prostaglandin E (by immunoassay) and {3H}PGE2 release from monocytes when compared with LPS-treated cultures . In contrast, IFN-gamma pretreatment did not potentiate labeled or immunoreactive TxB2 release from LPS-treated monocytes . IFN-gamma pretreatment without LPS stimulation did not result in elevated eicosanoid release over controls . In addition, continuous treatment of monocytes with both IFN-gamma and LPS did not result in greater release of PGE2 and TxB2 than the summed individual effects of IFN-gamma and LPS . These results indicate that IFN-gamma selectively potentiates LPS-stimulated arachidonic acid conversion to PGE2 and not TxB2 in human monocytes . This effect was observed only for monocytes pretreated with IFN-gamma prior to stimulation with LPS. Jpn J Cancer Res, 1987 Feb, 78(2), 153 - 61 Metabolic activation of phenacetin and phenetidine by several forms of cytochrome P-450 purified from liver microsomes of rats and hamsters; Nohmi T et al.; Metabolic activation of phenacetin by liver microsomes proceeds via both phenetidine and N-hydroxyphenacetin to direct-acting mutagens, i.e., N-hydroxyphenetidine and p-nitrosophenetole . Five different molecular species of cytochrome P-450 have been purified from liver microsomes of drug-pretreated Wistar rats or Syrian hamsters and their abilities to activate phenetidine and phenacetin were compared using reconstituted microsome systems . High-spin forms of cytochrome P-450 purified from 3-methylcholanthrene-pretreated rats (MC-P-448-H) or hamsters (P-488 ham-II) showed higher catalytic activity for N-hydroxylation of phenetidine than three other low-spin forms of cytochrome P-450 purified from the same animals or from phenobarbital-pretreated rats . MC-P-448-H and P-488 ham-II required the presence of cytochrome b5 for their maximum activities in the reconstituted system . The five forms of cytochrome P-450, however, exhibited no measurable activity for N-hydroxylation of phenacetin either with or without cytochrome b5 . The mutagenicity of phenacetin and phenetidine toward Salmonella typhimurium TA100 was generated when the reconstituted microsomes containing MC-P-488-H or P-488 ham-II were used as activating enzymes . From these results, it was suggested that high-spin forms of cytochrome P-450 (MC-P-448-H and P-448 ham-II) played an important role in the metabolic activation of phenacetin to the direct-acting mutagens. Mutat Res, 1987 Feb, 182(1), 31 - 9 Comparison of metabolic activation of carcinogens in human, rat, and hamster hepatocytes; Synder S et al.; The activities to activate and detoxify procarcinogens were compared in intact hepatocytes from humans, Sprague-Dawley rats and Syrian golden hamsters . Mutagenic metabolites that were released from the isolated hepatocytes were detected by mutation induction in co-cultivated Salmonella typhimurium TA98 . Hepatocytes from the 3 animal species all activated aflatoxin B1 (AFB1), acetylaminofluorene (AAF) and aminofluorene (AF) and released active metabolites to induce mutation in the indicator S . typhimurium T98 . Hamster hepatocytes were more effective than were human and rat hepatocytes to mediate mutation of Salmonella TA98 by AFB1, AAF and AF . Hepatocytes of human and rat failed to mediate mutation by 1-aminopyrene (1-AP) . Indeed, at low concentration of 1-AP and 1-nitropyrene (1-NP), the presence of the hepatocytes decreased the number of TA98 revertants . Only at higher concentrations of 1-aminopyrene and 1-nitropyrene did hamster hepatocytes increase mutation frequencies of indicator cells over the control groups . It seems that hepatocytes, particularly human hepatocytes, are better able to absorb and detoxify 1-AP and 1-NP than to activate them. Mutat Res, 1987 Feb, 176(2), 179 - 84 Mutagens formed from butylated hydroxyanisole treated with nitrite under acidic conditions; Mizuno M et al.; The reaction products from butylated hydroxyanisole treated with nitrite under acidic conditions were investigated for mutagenic activity in Salmonella typhimurium his reversion assay and for DNA-damaging activity using H17 Rec+ (wild) and M45 Rec- (recombinationless) of Bacillus subtilis . The chloroform extract of the reaction mixture showed 9 spots on thin-layer chromatography (TLC) . Compounds from 2 spots on the TLC had high mutagenic activity in TA100 without S9 mix, with DNA-damaging activity . The 2 mutagens were then crystallized from the reaction mixture and identified to be 2-tert.-butyl-p-quinone (t-BQ) and the dimer of t-BQ; 3,3'-di-tert.-butyl-biphenyldiquinone-(2,5,2',5') (BBDQ), from their instrumental analysis . The mutagenic activities of t-BQ and BBDQ were determined by Ames test, and the induced mutation frequencies were about 1.9 X 10(-4) (t-BQ) and 8.3 X 10(-5) (BBDQ). Mutat Res, 1987 Feb, 176(2), 165 - 70 Metabolic activation of emodin in the reconstituted cytochrome P-450 system of the hepatic microsomes of rats; Tanaka H et al.; Studies were undertaken to elucidate further the mechanism by which emodin, an anthraquinoid mycotoxin and constituent of rhubarb, was converted into a direct-acting mutagen to Salmonella typhimurium TA1537 by the hepatic microsomes and the reconstituted cytochrome P-450 system . Emodin was activated into a mutagenic principle(s) in the reconstituted cytochrome P-450 system, and its mutagenicity was significantly higher with the fraction II (P-448 type) than the fraction I (P-450 type) derived from the hepatic microsomes of PCB-induced rats . Thin-layer chromatographic analysis revealed that the purified cytochrome II-a (maximal CO-differential spectrum at 448.0 nm and high-spin form) activity converted emodin into 2-hydroxy-emodin, a direct-acting mutagen. Infect Immun, 1987 Feb, 55(2), 288 - 92 Differentiation and interaction of secretory immunoglobulin A and a calcium-dependent parotid agglutinin for several bacterial strains; Rundegren J et al.; Previous studies have suggested that both secretory immunoglobulin A (sIgA) and various nonimmunoglobulin salivary glycoproteins are capable of agglutinating a variety of bacteria . The present study was designed to compare the nature of the agglutinins for Streptococcus mutans and Salmonella typhimurium in parotid saliva and colostrum . S . mutans was aggregated by saliva and colostrum, whereas S . typhimurium was aggregated only by saliva as detected by a spectrophotometric method . The principal salivary agglutinin for both S . mutans and S . typhimurium was calcium dependent and could be desorbed in phosphate-buffered saline (pH 6.8) . In contrast, the colostral agglutinin was calcium independent and not readily desorbed . The agglutinin activities of saliva and colostrum for S . mutans were additive, suggesting independent target sites on the bacterial surface . The agglutinin activity of colostrum was totally associated with sIgA as was suggested by blocking of the agglutinating activity with anti-alpha-chain serum and the absence of blocking with an antibody specific for salivary agglutinin . Interestingly, anti-alpha-chain serum removed all agglutinating activity from saliva, but not from the phosphate-buffered saline-desorbed agglutinin . Dialysis of parotid saliva against 0.1 M disodium EDTA eliminated the agglutinin blocking activity of anti-alpha-chain serum but not that of the antiagglutinin antibody . The ability of anti-alpha-chain serum to block agglutination of the EDTA-dialyzed saliva could be restored by the addition of calcium chloride, suggesting that sIgA and salivary agglutinin are associated through a calcium-mediated interaction . These results indicate that bacterial agglutinating activity of colostrum, as detected spectrophotometrically, is mediated by sIgA, and that of saliva is mainly dependent upon a calcium-dependent nonimmunoglobulin agglutinin . The agglutinating activities of sIgA and parotid agglutinin seem to be additive, and their calcium-dependent association may favor the enhancement of their respective activities. Antimicrob Agents Chemother, 1987 Feb, 31(2), 230 - 7 Decreased binding of antibiotics to lipopolysaccharides from polymyxin-resistant strains of Escherichia coli and Salmonella typhimurium; Peterson AA et al.; The interactions of polycationic antibiotics with lipopolysaccharide (LPS) isolated from parental and polymyxin-resistant strains of Salmonella typhimurium and Escherichia coli were measured by using a cationic spin probe . Electron spin resonance spectra indicated that increasing concentrations of cations competitively displaced probe from LPS aggregates . Polymyxin B and other cations displaced less probe from LPS of polymyxin-resistant strains than from LPS of the parental strains, whereas the same amount or more probe was displaced from isolates of the mutants by the structurally similar antibiotic, EM 49 (octapeptin) . In general, the differential affinities of these antibiotics for LPS correlated with their antibiotic activity in vivo, suggesting that resistance results from a decrease in antibiotic permeability across the outer membrane due to alterations in the LPS which affect antibiotic binding . The alterations in the structure of LPS from the polymyxin-resistant mutants of E . coli were characterized using 31P nuclear magnetic resonance spectroscopy . Th