Publications
| Title | Abstract | Year Filter | PMID(sorted ascending) Filter |
|---|
| differences between the anthranilate-5-phosphoribosylpyrophosphate phosphoribosyltransferases of salmonella typhimurium strains lt2 and lt7. | the anthranilate-5-phosphoribosylpyrophosphate phosphoribosyltransferases (prt), coded by the second structural gene (trpb) of the tryptophan (trp) operon in strains lt2 and lt7 of salmonella typhimurium, differ from each other in a number of parameters. these include the apparent km values for their substrates anthranilic acid and 5-phosphoribosylpyrophosphate, thermostability, sensitivity to substrate inhibition by anthranilic acid, as well as end-product inhibition by tryptophan and specific ... | 1979 | 383894 |
| transduction of fimbriation demonstrating common ancestry in firn strains of salmonella typhimurium. | the production of fimbriate (fim+) recombinants was observed in transductional crosses between different pairs of wild-type strains of different biotypes of salmonella typhimurium. fim+ recombinants were readily produced in transductions from fim+ donor strains to fim- recipient strains and, less frequently, between some pairs of fim- strains, for example, between almost any strain of the firn biogroup (fim- inl- rha- bxyl-) and many strains of the non-firn fim- biogroup. none of numerous crosse ... | 1979 | 383900 |
| inhibition of 2-fluorenamine-induced mutagenesis in salmonella typhimurium by vitamin a. | vitamin a alcohol (retinol) completely inhibited the mutagenicity of the carcinogen 2-fluorenamine (2-fa) in salmonella typhimurium ta98 when the mutagen was activated by liver microsomes from cfn rats. the mutagenicity of 2-fa activated by 9,000xg rat liver supernatant s9 was inhibited by retinol to a lesser degree. the decline in the number of his+ revertants was not an artifact due to bacterial killing, inasmuch as retinol was not toxic to the bacteria at levels that totally inhibited mutagen ... | 1979 | 384006 |
| concentration-dependent mutation by alkylating agents in human lymphoblasts and salmonella typhimurium: n-methyl-n-nitrosourethane and beta-propiolactone. | the toxic and mutagenic effects of the alkylating agents n-methyl-n-nitrosourethane (mnut) and beta-propiolactone (bpl) were quantitatively measured in human lymphoblasts and salmonella typhimurium. forward mutation to 6-thioguanine resistance was measured in the human lymphoblasts, and forward mutation to 8-azaguanine resistance was measured in the bacterial cells after equigenerational (1.5 doubling times) exposures. in both systems, the induced mutant fraction rose linearly as a function of c ... | 1979 | 384009 |
| assay for mutagenicity of bile in sprague-dawley rats treated subcutaneously with intestinal carcinogens. | to investigate the mode of action of sc injected intestinal carcinogens, the mutagenicity assay of bile collected from noninbred sprague-dawley rats treated sc with carcinogens was conducted in the presence and absence of beta-glucuronidase. the bile samples from rats inoculated with 4-aminobiphenyl were mutagenic for salmonella typhimurium ta100 only in the presence of beta-glucuronidase, whereas those from the 3,2'-dimethyl-4-aminobiphenyl-treated rats did not require the enzyme for mutagenici ... | 1979 | 384011 |
| the in vitro detection of defects in temperature sensitive rna polymerases from mutants of salmonella typhimurium. | 1979 | 384150 | |
| mutagenicity of 8-ethoxycaffeine in vitro. induction of point mutations in the salmonella/microsome test and of sister-chromatid exchanges as well as chromosomal aberrations in chinese hamster ovary cells (cho line). | the caffeine derivative 8-ethoxycaffeine (eoc) was tested in 3 different test systems in vitro. each experiment was carried out with and without s9 mix. incubation temperatures were 20 and 37 degrees c. (1) in the salmonella/microsome test, eoc behaved as a pro-mutagen in the salmonella typhimurium strain ta1535. no mutagenic activity was found in experiments without s9 mix. the influence of temperature was negligible. the mutagenic activity of eoc depended mainly on the mammals used to prepare ... | 1979 | 384216 |
| dna--benzo[a]pyrene adducts formed in a salmonella typhimurium mutagenesis assay system. | the dna adducts formed in salmonella typhimurium when bacteria are incubated with radioactive benzo[a]pyrene and liver microsomal enzymes from several sources has been investigated. when enzyme preparations from aroclor i254 or 3-methylcholanthrene induced c57bl/6n (b6) mice were used to mediate activation, the predominant product was an adduct between the 10 position of 7 beta, 8 alpha-dihydroxy-9 alpha, 10 alpha epoxy-7,8,9,10-tetrahydrobenzo[a]pyrene and the n-2 position of deoxyguanosine. si ... | 1979 | 384221 |
| reversal of sodium-azide mutagenicity by liver preparations and by gastric juice. | sodium azide was found to be mutagenic for salmonella typhimurium by inducing base-pair substitutions that were not enhanced by pkm101 plasmid (r factor). however, the mutagenicity of sodium azide was decreased by enzyme proteins contained in rat-liver post-mitochondrial fractions, depending on the nadph-generating system. pre-incubation with human gastric juice also decreased azide mutagenicity. these metabolic effects might explain the conflicting nature of the mutagenicity and carcinogenicity ... | 1979 | 384225 |
| mutagens in the feces of 3 south-african populations at different levels of risk for colon cancer. | the incidence of mutagens in the feces of 3 south-african populations at different risk levels for colon cancer has been determined. lyophilized fecal samples were extracted with ether and the mutagenicity of the extracts determined using the salmonella/mammalian microsome mutagenicity test. 19% of the samples from urban white south-africans, a population at a high risk for colon cancer, were mutagenic using salmonella typhimurium strain ta100. this incidence was significantly greater (p less th ... | 1979 | 384227 |
| the l-arabinose-resistance test with salmonella typhimurium strain sv3 selects forward mutations at several ara genes. | a new assay has been described for mutagenicity testing using an l-arabinose-sensitive strain of salmonella typhimurium. the test strain sv3 and several l-arabinose-resistant mutants selected therefrom are characterized in the present study by 3 different criteria: inhibition of growth by l-arabinose, accumulation of keto-sugars, and activities of the enzymes involved in l-arabinose catabolism. strain sv3 (ara-531) shows high levels of inducible l-arabinose isomerase (ec 5.3.1.4) and l-ribulokin ... | 1979 | 384229 |
| platinum(ii) complexes generate frame-shift mutations in test strains of salmonella typhimurium. | cis-diamminodichloroplatinum(ii) (cis-pdd) and diaquoethylenediamineplatinum(ii) induce histidine revertants in salmonella typhimurium strains ta98 (frame-shift mutation) and ta100 (base-pair substitution mutation). a linear dose--response relationship is found with cis-pdd acting on ta98 and ta100. salmonella typhimurium strains ta1535, ta1537 and ta1538 are not sensitive to the mutagenic action of cis-pdd. all 5 strains are sensitive to the toxic effect of cis-pdd. platinum(ii) complexes induc ... | 1979 | 384231 |
| derivatives of side-chain hydroxylated nitrosamines direct acting mutagens in salmonella typhimurium. | methyl-(beta-tosyloxyethyl)nitrosamine and 3-methyl-4,5-dihydro-1,2,3-oxadiazolium tosylate are potent direct acting mutagens in the ames assay, as is n-nitrosoprolinyl tosylate. these compounds are derived from beta-hydroxylated nitrosamines. the closely related methyl-(gamma-tosyloxypropyl)nitrosamine is not mutagenic without activation. these data are consistent with the chemical behavior of these substances, which suggest that suitable derivatives of beta-hydroxylated nitrosamines, such as o ... | 1979 | 384234 |
| [the anodically moving thermolabile antigen (ata) of gram negative bacteria. protection of mice by immunization with ata (author's transl)]. | mice are protected against lethal doses of salmonella typhi-murium by vaccination with ata extracted from providencia. no protective effect is observed when the s. typhi-murium strains are enterotoxigenic. thus protection is antibacterial, but not antitoxic. | 1979 | 384750 |
| mutagenic activity of fusarium moniliforme isolates in the salmonella typhimurium assay. | a total of 33 isolates of fusarium moniliforme from several food or feed crops were grown on sterile cracked corn, and chloroform-isopropanol extracts were assayed for mutagenic activity in the salmonella typhimurium-microsome system by using tester strain ta98 or ta100 or both. extracts of 21 (64%) of the isolates assayed against ta100 were mutagenic. activities of seven of these extracts were increased markedly with incorporation of the liver homogenate (s-9) into the assay. seven (33%) of the ... | 1979 | 384905 |
| [geographic distribution of biotypes of salmonella typhimurium var. copenhagen in belgium]. | 1978 | 384913 | |
| covalent linkage of lipoprotein to peptidoglycan is not essential for outer membrane stability in proteus mirabilis. | isolated rigis layers from proteus mirabilis harvested at different growth phases were degraded by endo-n-acetylmuramidase from chalaropsis b, and the degradation products were investigated. the results show the complete absence of covalently linked lipoprotein in exponential-phase cultures. stationary cells, however, possess covalently linked lipoprotein in amounts similar to those found in escherichia coli or salmonella typhimurium during all growth phases. the overall peptidoglycan structure ... | 1979 | 384953 |
| a single amino acid substitution in a histidine-transport protein drastically alters its mobility in sodium dodecyl sulfate-polyacrylamide gel electrophoresis. | mutation hisj5625 has altered the histidine-binding protein j of salmonella typhimurium such that histidine transport is impaired, even though binding of histidine by the j protein is unimpaired [kustu, s.g., & ames, g.f. (1974) j. biol. chem. 249, 6976--6983]. we have determined by protein analytical methods that the only effect of this mutation has been the substitution of a cysteine residue for an arginine at a site in the interior of the polypeptide chain. this arginine residue is therefore ... | 1979 | 385047 |
| studies on experimental enteric salmonellosis in ponies. | clinical, bacteriological, serological and haematological observations were made on 13 adult ponies orally inoculated with salmonella typhimurium. the results were compared to two control ponies and four others infected by accidental transmission. the clinical responses in inoculated ponies included pyrexia lasting four days and neutropaenia during the first five days after inoculation followed by a neutrophilia. pyrexia and neutropaenia was associated with maximal shedding of organisms in the r ... | 1979 | 385122 |
| the influence of cations on the permeability of the outer membrane of salmonella typhimurium and other gram-negative bacteria. | the high sensitivity of rough mutants of salmonella typhimurium, s. minnesota, and escherichia coli 08 (i.e. with defects in the carbohydrate core of the lipopolysaccharide) to several antibiotics and to the dye gentian violet could be substantially reduced by the addition of cations (mg2+, na+) into the growth medium. one heptoseless mutant of s. typhimurium (chemotype re) and its isogenic smooth parent strain were studied in more detail. the uptake of gentian violet was about 20% in the smooth ... | 1979 | 385129 |
| free flying sparrows as carriers of salmonellosis. | salmonella typhimurium was isolated from nine of 60 wild sparrows trapped in the guelph area. while this organism was isolated from birds trapped at several different locations, the highest prevalence was in sparrows trapped in close proximity to an animal clinic. the significance of these findings in relation to human and animal salmonellosis is discussed. | 1979 | 385137 |
| locating salmonella resistance gene on mouse chromosome 1. | the inherited resistance of inbred mouse strains to salmonella typhimurium injected subcutaneously has been reported to be controlled primarily by a single gene designated ity. resistant mice have the dominant allele ityr and sensitive mice are homozygous for the recessive allele itys. this paper describes studies undertaken to locate the gene using readily distinguishable phenotypes as chromosome markers. appropriate f1 backcross and f2 generations of hybrids between resistant and susceptible i ... | 1979 | 385184 |
| characterization of a mutator dna polymerase i from salmonella typhimurium. | 1979 | 385235 | |
| bactericidal activity of fractionated granule contents from human polymorphonuclear leukocytes: antagonism of granule cationic proteins by lipopolysaccharide. | granule extracts from human polymorphonuclear leukocytes (pmn) were prepared with 0.2 m (ph 4.0) acetate. a fraction (valley ab) with distinctive bactericidal activity against cell wall mutants of salmonella typhimurium lt-2 was obtained after fractionation of the granule extracts by sephadex g-100 column chromatography. the smooth parent lt-2 strain was less sensitive to the bactericidal action. susceptibility of the rough mutants to bactericidal action increased as sugar residues decreased in ... | 1979 | 385501 |
| membrane receptors for aspartate and serine in bacterial chemotaxis. | high affinity binding sites for serine and aspartate have been characterized in membranes from salmonella typhimurium and escherichia coli. greater than 80% of these sites have been identified as chemotaxis receptors. mutants lacking binding sites for these amino acids have been shown to have corresponding defects in taxis. the substrate specificity of each of the receptors in salmonella is very high; most analogs of serine and aspartate do not bind to these receptor sites and do not affect chem ... | 1979 | 385590 |
| in vivo methylation of prokaryotic elongation factor tu. | in salmonella typhimurium and escherichia coli, elongation factor tu (ef-tu) is methylated as shown by its incorporation of labeled methyl residues from [methyl-3h]methionine. analysis of the nature of the methyl-containing residues by protein hydrolysis, followed by paper chromatography and high voltage electrophoresis showed that both mono- and dimethyllysine are present. eighty per cent of the ef-tu molecules are methylated if methylation occurs at a unique lysine residue. the ef-tu fraction ... | 1979 | 385603 |
| the effect on the virulence and infectivity of salmonella typhimurium and salmonella gallinarum of acquiring antibiotic resistance plasmids from organisms that had caused serious outbreaks of disease. | antibiotic resistance plasmids from organisms that had caused serious epidemics, including those responsible for epidemics of chloramphenicol-resistant typhoid fever and dysentery in central america, were transferred to a strain of salmonella typhimurium and of salmonella gallinarum. the virulence and infectivity of these r(+) forms were then compared with the r(-) parent forms in orally inoculated chickens.none of the r(+) forms were more virulent than their r(-) parent forms. the mortality rat ... | 1979 | 385769 |
| mutagenic effects of benzo[a]pyrene after metabolic activation by hepatic 9000 g supernatants or intact hepatocytes. | the activating capacities of isolated rat hepatocytes and 9000 g supernatant from these cells with respect to the mutagenic effect of benzo[a]pyrene on salmonella typhimurium ta100 were investigated. no mutagenicity of benzo[a]pyrene was found with the cell-mediated assay, unless the hepatocytes were disrupted after pre-incubation with benzo[a]pyrene or the intracellular glutathione content was reduced. it is suggested that a retention of active metabolites and an effective detoxication may acco ... | 1979 | 386101 |
| the mutagenicity of nitrosamides in salmonella typhimurium. | 34 nitrosamides (10 nitrosoalkylcarbamates, 2 nitrosoalkylnitroguanidines, 12 nitrosoalkylureas, 6 substituted nitrosoalkylureas, and 4 cyclic nitrosoalkylureas) were tested for mutagenicity in salmonella. all were direct-acting mutagens of varying potency. | 1979 | 386106 |
| in vivo conversion of sodium azide to a stable mutagenic metabolite in salmonella typhimurium. | salmonella typhimurium ta1530 and g46 strains growing in minimal medium supplemented with sodium azide produce a stable mutagenic metabolite which is not azide. the production of this metabolite is restricted to the log phase of bacteria grown in the presence of azide. the metabolite is highly mutagenic in dna-repair defective base-substitution strains ta1530 and ta1535, but ineffective in frameshift strains ta1538 and ta1537. the metabolite induces mutations in resting cells of the ta1530 strai ... | 1979 | 386107 |
| mutagenic cholesterol preparations. | naturally air-aged commercial samples of usp or reagent-grade cholesterol contain components which are mutagenic towards salmonella typhimurium strains ta1537, ta1538 and ta98. these mutagenic components are associated with the polar cholesterol autoxidation products, but identity of the mutagenic components has not been achieved. pure crystalline nonmutagenic cholestrol free from autoxidation products becomes mutagenic towards these strains upon heating at 70 degrees in air or following exposur ... | 1979 | 386108 |
| mutagenicity evaluation of the two antimalarial agents chloroquine and mefloquine, using a bacterial fluctuation test. | the two antimalarial agents chloroquine and mefloquine have been tested for mutagenicity in salmonella typhimurium strains ta1535, ta1537 and ta1538. chloroquine was found to revert strain ta1537 at concentrations of 100 and 250 micrograms/ml, most likely due to intercalation. no mutagenicity was found with mefloquine at concentrations up to 2.5 micrograms/ml, neither without nor with metabolic activation by ca2+-precipitated rat liver microsomes. higher concentrations of mefloquine and chloroqu ... | 1979 | 386109 |
| genetic toxicity of procarbazine in bacteria and yeast. | procarbazine [n-isopropyl-alpha-(2-methylhydrazino)-p-toluamide hydrochloride] is used to treat hodgkin's disease. this compound was tested in vitro without and with s10 fraction from mice liver (microsomal assay) using saccharomyces cerevisiae strain d7, salmonella typhimurium (strains ta98, ta100, ta1535) and in vivo in swiss albino mice (host-mediated assay) using d7. procarbazine, without s10 fraction, is highly toxic and induced mitotic crossover, gene conversion, and reverse mutation in d7 ... | 1979 | 386110 |
| mutagenic activity of thiram in ames tester strains of salmonella typhimurium. | the mutagenic activity of thiram was investigated in 4 histidine-requiring strains of salmonella typhimurium (ta1535, ta100, ta1538, ta98) with and without activation by liver microsomes. in strains ta1535 and ta100, thiram induces mutations without metabolic activation. the presence of rat-liver microsome fraction, cysteine or glutathione abolish its mutagenic activity in these strains. in contrast, thiram requires metabolic activation for the expression of its mutagenic activity in ta1538 and ... | 1979 | 386113 |
| [sepsis and peritonitis caused by salmonella typhimurium in a patient splenectomized for pancytopenia]. | 1979 | 386167 | |
| isolation and mapping of plasmids containing the salmonella typhimurium origin of dna replication. | a purified ecori restriction endonuclease fragment that determines resistance to kanamycin and is incapable of self-replication was used to select autonomously replicating fragments from an ecori digest of a salmonella typhimurium f' plasmid containing the chromosomal region believed to include the s. typhimurium origin of dna replication. both the f factor and s. typhimurium chromosome replication origins were cloned by this procedure. the ecori fragmentment containing the s. typhimurium origin ... | 1979 | 386330 |
| permeabilization of cells for studies on the biochemistry of bacterial chemotaxis. | the cell membranes of salmonella typhimurium and escherichia coli have been made permeable in order to introduce s-adenosylmethionine into the cell for study of the course of methylation. a series of protein bands in the mr 60,000 region were methylated, the specific bands and the extent of methylation depending on the attractant used. the change in levels of methylation was essentially the same as the in vivo responses, indicating that the permeabilization procedure maintains the relative relat ... | 1979 | 386344 |
| experimental klebsiella and salmonella infection in neonatal swine. | twenty colostrum-fed piglets from three sows were separated from the sows 24 hours after birth and were randomly divided into five groups of four piglets each. every piglet in each of four test groups was orally inoculated with about 10(10) colony forming units of salmonella typhimurium, salmonella choleraesuis var kunzendorf or one of two isolates of klebsiella pneumoniae. one group served as uninoculated controls. piglets infected with k. pneumoniae developed severe diarrhea beginning about 12 ... | 1979 | 387185 |
| transfer of f'lac+ plasmid from salmonella typhimurium to shigella flexneri. | 1978 | 387348 | |
| histidine mutants requiring adenine: selection of mutants with reduced hisg expression in salmonella typhimurium. | a method is described for the selection of salmonella typhimurium mutants with reduced levels of hisg enzyme activity. this method is based on the fact that the hisg enzyme catalyzes the consumption of atp in the first step of histidine biosynthesis. normally, this reaction is closely regulated, both by feedback inhibition and by repression of the operon. however, conditions can be set up that result in the uncontrolled use of adenine in histidine biosynthesis. cells grown under these conditions ... | 1979 | 387516 |
| a refined map of the hisg gene of salmonella typhimurium. | the hisg gene is the most operator-proximal structural gene of the histidine operon; it encodes the feedback-inhibitable first enzyme of the biosynthetic pathway. previously, hisg mutants were mapped into seven intervals defined by the availble deletion mutations having endpoints in the hisg gene. the map has been refined using over 60 new deletion mutants. the new map divides the gene into 40 deletion intervals, which average approximately 30 base pairs in length. the map has been used to analy ... | 1979 | 387517 |
| [effect of bacterial insecticides on soil self-purification processes and on the survival in the soil of pathogenic enterobacteria with the example of salmonella typhimurium]. | 1979 | 387535 | |
| [acute renal failure and hypocomplementemia associated with salmonella typhimurium infection]. | 1979 | 387548 | |
| absence of mutagenic activity in salmonella typhimurium of some impurities found in saccharin. | 1979 | 387554 | |
| immunization with major outer membrane proteins in experimental salmonellosis of mice. | porin (outer membrane protein) preparations extracted from a rough (rb2) mutant of salmonella typhimurium proved to be good immunogens in mice and rabbits. the antibody response achieved was measured by using enzyme-linked immunosorbent assay techniques. high titers of both antiporin and antilipopolysaccharide were detected in both species. the rabbit antiserum raised against the porins and the porin preparations themselves had a highly significant protective capacity against intraperitoneal sal ... | 1979 | 387596 |
| artificial salmonella vaccines: o-antigenic oligosaccharide-protein conjugates induce protection against infection with salmonella typhimurium. | outbred mice were vaccinated with various artificial salmonella vaccines and subsequently challenged intraperitoneally with graded doses of virulent salmonella typhimurium. the salmonella vaccines used were: (i) octasaccharide, obtained by hydrolysis of the o-antigenic polysaccharide chain of s. typhimurium strain sh 4809 with phage p22-associated endo-rhamnosidase and covalently linked to either diphtheria toxin or edestine; (ii) purified outer membrane proteins (porins) from s. typhimurium; an ... | 1979 | 387597 |
| collaborative studies on the salmonella/microsome mutagenicity assay. | although the salmonella/plate test has been used extensively, a collaborative study was undertaken to determine the interlaboratory reproducibility of this microbial mutagenicity assay. four laboratories participating in the study have completed testing, under code, of 61 carcinogens and noncarcinogens. all chemicals were tested both with and without metabolic activation in salmonella typhimurium strains ta1535, 1537, 1538, 98, and 100. the metabolic activation systems used were derived from the ... | 1979 | 387710 |
| regulation of o-acetylserine sulfhydrylase b by l-cysteine in salmonella typhimurium. | a technique based on resistance to azaserine was used to isolate mutants lacking o-acetylserine sulfhydrylase b, one of two enzymes in salmonella typhimurium capable of synthesizing l-cysteine from o-acetyl-l-serine and sulfide. the mutant locus responsible for this defect has been designated cysm, and genetic mapping suggests that cysm is very close to and perhaps contiguous with cysa. strains lacking either o-acetylserine sulfhydrylase b or the second sulfhydrylase, o-acetylserine sulfhydrylas ... | 1979 | 387718 |
| immuno-electron microscopic localization of lipopolysaccharide antigens on ultrathin sections of salmonella typhimurium. | lipopolysaccharide antigens were demonstrated on ultrathin sections of styrene-embedded salmonella typhimurium by direct postembedding staining with ferritin-labeled antibodies. the antigenicity, partially masked in the embedding process, could be satisfactorily recovered by treatment of ultrathin sections with nonspecific protease. as judged from the reaction site of the ferritin-labeled antibodies, the lipopolysaccharides were localized in two zones. the broader zone of densely distributed fer ... | 1979 | 387723 |
| role of gene flafv on flagellar hook formation in salmonella typhimurium. | nine temperature-sensitive nonflagellate mutants defective in flafv were isolated from a strain of salmonella typhimurium. among them three mutants were found to produce flagella with abnormally shaped (either straight or irregularly curved) hooks at the permissive temperature. two mutations that rendered hooks straight were located in one of the eight segments of flafv defined by deletion mapping. the mutation that rendered hooks irregularly curved was located in a different segment. an flar mu ... | 1979 | 387724 |
| chemotaxis of salmonella typhimurium toward citrate. | salmonella, but not escherichia coli, was attracted to citrate, a distinction that is understandable in view of the inability of e. coli to transport tricarboxylic acids. the salmonella response to citrate and to two previously described attractants, aspartate and malate, was mutually noncompetitive. citrate taxis different from citrate uptake in that it did not require na+, was constitutive, and was not repressible by glucose. | 1979 | 387726 |
| electron acceptor taxis and blue light effect on bacterial chemotaxis. | salmonella typhimurium and escherichia coli from anaerobic cultures displayed tactic responses to gradients of nitrate, fumarate, and oxygen when the appropriate electron transport pathway was present. such responses were named "electron acceptor taxis" because they are elicited by terminal electron acceptors. mutant strains of s. typhimurium and e. coli were used to establish that functioning electron transport pathways to nitrate and fumarate are required for taxis to these compounds. aerotaxi ... | 1979 | 387740 |
| deoxyribonucleic acid adenine and cytosine methylation in salmonella typhimurium and salmonella typhi. | the methylations of adenine in the sequence -gatc- and of the second cytosine in the sequence - [formula: see text] - were studied in salmonella typhimurium and in salmonella typhi. the study was carried out by using endonucleases which restrict the plasmid pbr322 by cleavage at the sequences -gatc- (dpni and mboi) and - [formula: see text] - (ecorii). the restriction patterns obtained for this plasmid isolated from transformed s. typhimurium and s. typhi were compared with those of pbr322 isola ... | 1979 | 387741 |
| pyridine nucleotide cycle of salmonella typhimurium: in vitro demonstration of nicotinamide mononucleotide deamidase and characterization of pnua mutants defective in nicotinamide mononucleotide transport. | the enzyme nicotinamide mononucleotide deamidase, an integral component of the proposed four-membered pyridine nucleotide cycle (pnc iv), has been demonstrated in extracts of salmonella typhimurium lt2. the enzyme has an optimum ph of 8.7 and deamidates nicotinamide mononucleotide, forming nicotinic acid mononucleotide. sigmoidal kinetic data suggest that this enzyme may be allosteric and therefore an important regulatory component of pyridine nucleotide cycle metabolism. mutants previously desi ... | 1979 | 387742 |
| interference of azide with cysteine biosynthesis in salmonella typhimurium. | the growth inhibition of salmonella typhimurium azia mutants by sodium azide is reversed by cystine and related compounds. nadph-sulphite reductase (hydrogen-sulphide:nadp+ oxidoreductase; ec 1.8.1.2), an enzyme of cysteine biosynthesis, is inhibited in cell extracts by sodium azide. azib mutants which are able to grow in the presence of the inhibitor without cystine were isolated. about half of them were mapped in the cysk gene and have only residual activity of its product, o-acetylserine sulp ... | 1979 | 387913 |
| salmonella bacteriophage glycanases: endorhamnosidases of salmonella typhimurium bacteriophages. | twelve bacteriphages lysing only smooth salmonella typhimurium strains were shown to have similar morphology--an icosahedric head to which a short, noncontractile tail carrying six spikes was attached. all phages degraded their lipopolysaccharide (lps) receptors as shown by their ability to cleave off [14c]galactosyl-containing oligosaccharides from s. typhimurium cells labeled in their lps. the oligosaccharides inhibited the alpha-d-galactosyl-specific bandeiraea simplicifolia lectin agglutinat ... | 1979 | 387979 |
| [laboratory and clinical studies on cefamandole (author's transl)]. | the authors have carried out the laboratory and clinical studies of cefamandole (cmd). the results are as follows: the sensitivity was measured by plate dilution method on 26 strains of staphylococcus aureus, escherichia coli, klebsiella pneumoniae and 14 strains of salmonella typhimurium isolated from patients. the distribution of sensitivity of s. aureus was 0.39 approximately 3.13 micrograms/ml and the peak of distribution was 1.56 micrograms/ml. the distribution of sensitivity of e. coli was ... | 1979 | 387993 |
| azide-induced mutagenesis in gram-negative bacteria is reca-and lexa-independent. | azide-induced mutagenesis was investigated in salmonella typhimurium and escherichia coli. azide was highly effective in inducing mutation in uvrb, uvrb reca and uvrb recb mutants of s. typhimurium. the mutagenic effect of azide was also observed in uvra lexa mutants of e. coli k12 and e. coli b/r. these results suggest that azide-induced mutagenesis is due to mis-replication of dna. | 1979 | 388210 |
| leu operon of salmonella typhimurium is controlled by an attenuation mechanism. | the nucleotide sequence of the control region of the leu operon of salmonella typhimurium was determined. a prominent feature of this region is a signal for termination of transcription. in vitro, transcription does terminate at this site, yielding a leader rna of about 160 nucleotides as a major product. this leader rna is potentially translatable into a peptide containing 28 amino acids, 4 of which are adjacent leucine residues. several regions of base complementarity exist within the leader, ... | 1979 | 388423 |
| nucleotide sequences of trpa of salmonella typhimurium and escherichia coli: an evolutionary comparison. | the complete nucleotide sequences of trpa of salmonella typhimurium and escherichia coli were determined. the nucleotide sequences are 24.8% divergent, compared with amino acid sequence divergence of 14.9%. over half of the codons of each gene contain synonymous nucleotide changes. the pattern of synonymous nucleotide changes is consistent with the interpretation that such changes result from random mutational events. we do not find any evidence indicating that codon selection or rna structure i ... | 1979 | 388433 |
| differences in mutagenicity and cytotoxicity of (+)- and (-)-benzo[a]pyrene 4,5-oxide: a synergistic interaction of enantiomers. | in order to study the biological effects of (+)- and (-)-benzo[a]pyrene 4,5-oxide, a synthesis of these molecules has been developed based on the resolution of (+/-)-cis-4,5-dihydroxy-4,5-dihydrobenzo[a]pyrene. the (-) enantiomer of benzo[a]pyrene 4,5-oxide was 1.5- to 5.5-fold more mutagenic than the (+) enantiomer in strains ta 98, ta 100, ta 1537, and ta 1538 of salmonella typhimurium and in chinese hamster v79 cells. in studies with v79 cells, the (-) enantiomer of benzo[a]pyrene 4,5-oxide w ... | 1979 | 388437 |
| [phage typing of salmonella typhimurium. preliminary scheme with locally adapted phages]. | 1978 | 388561 | |
| effects of pretreatment with 2,3,7,8-tetrachlorodibenzo-p-dioxin on the capacity of hepatic and extrahepatic mouse tissues to convert procarcinogens to mutagens for salmonella typhimurium auxotrophs. | 1979 | 388724 | |
| the smob mutation suppressing cell filamentation and ability to support the multiplication of phage p22 in salmonella typhimurium. | isolation and properties of a salmonella typhimurium mutant smob are described. the mutation maps at unit 99 of the s. typhimurium chromosome between pyrb and deoc. it suppresses cell filamentation and temperature sensitivity of histidine-constitutive mutants, but does not restore the normal regulatory pattern to the histidine operon. strains carrying the mutation have greatly reduced ability to support the growth of phage p22, but not of es18 or felix o. | 1979 | 388953 |
| on the different response of salmonella typhimurium hisg46 and ta1530 to mutagenic action of base analogues. | various mutagens are known to induce more his+ revertants in ta1530 than in hisg46 strain. to test whether the mutator effect shown by ta1530 is limited to the his mutation, the lysa8 marker was introduced into both the ta1530 and hisg46 strain, and its reversibility, after induction by n4-hydroxycytidine, was estimated. the ability to reverse the lys marker was tenfold higher in the ta1530/lysa8 transductants than in the hisg46/lysa8 transductants or in the donor for lys, the lysa8 strain. | 1979 | 388954 |
| properties of cysk mutants of escherichia coli k12. | triazole and azaserine resistant mutants of e. coli k12 affecting cysk gene coding for o-acetylserine sulphydrylase were isolated. the cysk gene in e. coli is located in the same region of chromosome as the cyck gene in salmonella typhimurium. all azaserine and some triazole resistant mutants require cysteine for growth at a normal rate. the cysk mutants have reduced sulphate uptake. stability and transfer by conjugation of triazole resistant phenotype were checked. differences in sulphate metab ... | 1979 | 388955 |
| integration of f factor and cryptic lt2 plasmid into a specific site of the salmonella typhimurium chromosome. | suppression of dnaa mutation by f'lac and cryptic lt2 plasmid was used for selecting clones containing these plasmids integrated into rfa and galk genes. | 1979 | 388957 |
| [epizootiology of salmonella typhimurium infection in chickens]. | the incidence of s. typhimurium infections among fowl increased in thr region of potsdam in general, and on various big farms in particular, 1976 and over the first half of 1977. the outbreaks included subclinical infections and clinically manifest diseases which caused remarkable loss of broilers from the affected stocks (up to 15.92 per cent). parent stocks contaminated with s. typhimurium were to be the sources of infection in all cases. a total of 1,220 salmonella strains were isolated from ... | 1979 | 389191 |
| the reduced mutagenicity of aflatoxin b1 due to hydroxylation: observations on five salmonella typhimurium tester strains. | the mutagenicity of aflatoxin m1 relative to that of aflatoxin b1, the parent compound, was studied in 5 ames' tester strains of salmonella typhimurium (ta 98, ta 100, ta 1535, ta 1537, ta 1538). aflatoxins b1 and m1 are both highly mutagenic in microsome-mediated system in ta 100. the prediction of the relative carcinogenicity of aflatoxin m1 to aflatoxin b1 posed by the mutation of ta 100 is probably more authentic than by ta 98. | 1979 | 389414 |
| formation of mutagens in cooked foods. i. beef. | mutagens detectable by salmonella typhimurium ta98, after activation by liver s-9 fraction, are formed when meat is cooked by frying, broiling and boiling. high levels of mutagenic activity are formed rapidly when frying, or more slowly during broiling. formation of mutagens in boiled beef stock requires several days under reflux, but shows a strong concentration dependence. time curves suggest that a period exists during which mutagens are not readily formed; however, after this period mutagen ... | 1979 | 389415 |
| mutagenic activity of gastric juice. | gastric juice samples from patients of a rural area of the colombian andes at high risk to gastric cancer were tested for mutagenesis with salmonella typhimurium strains ta100 and ta1538. direct mutagenic effect was found in samples with detectable amounts of nitrite. this effect was not accountable by nitrite alone. nitrite-negative samples from the same area and samples from the low-risk area of cali were negative using the same mutagenesis assay. | 1979 | 389416 |
| mutagenicity of metabolites of carcinogenic aminoazo dyes. | the mutagenicity of 8 azo dyes and 6 p-phenylenediamine derivatives, which comprised the metabolites of carcinogenic 4-aminoazobenzene derivatives, was studied on salmonella typhimurium ta98 and ta100. 4'-hydroxy-n-methyl-4-aminoazobenzene and its o-sulfate and o-glucuronide, and 3-hydroxy-4-aminoazobenzene were mutagenic on ta98 in the presence of s-9 mix. p-phenylenediamine and its o-methoxyl derivative were definitely mutagenic on ta98 with the addition of s-9 mix. all metabolites tested were ... | 1979 | 389418 |
| mutagenic factors in cooked foods. | the charred surface of fish and beef showed strong mutagenic activity in salmonella typhimurium test strains when activated by s-9 mix of rat liver. the pyrolysis products of proteins and amino acids were also highly mutagenic. among the pyrolysis products of amino acids, those of tryptophan, serine, and glutamic acid were most active. the new gamma-carboline derivatives, 3-amino-1,4-dimethyl-5h-pyrido[4,3-b]indole and 3-amino-1-methyl-5h-pyrido[4,3-b]indole, were purified from the pyrolysis pro ... | 1979 | 389565 |
| methylmethacrylate is a mutagen for salmonella typhimurium. | the long-term effects of exposure to monomeric methylmethacrylate have yet to be established. we have measured the toxicity and mutagenicity of methylmethacrylate for salmonella typhimurium. at levels of thirty-four millimolar, methylmethacrylate exhibited 28 per cent of the mutagenic activity of an equimolar dose of dimethylnitrosamine. methylmethacrylate alone exhibited toxicity to the bacteria, but when the methylmethacrylate was incubated with a rat-liver enzyme metabolizing system, mutagene ... | 1979 | 389931 |
| three-dimensional image reconstruction of straight flagella from a mutant salmonella typhimurium. | 1979 | 390160 | |
| host transcription in bacteriophage p22-infected salmonella typhimurium. | the kinetics of host rna synthesis, as measured by pulse-label kinetics and rna-dna hybridization, is inhibited 10-fold shortly after infection with bacteriophage p22. this early inhibition lasts through the first 6 min of infection and affects not only rna synthesis but several other energy-requiring cellular functions. in lysogenic infections, the rate of bacterial transcription rapidly recovers to the value of uninfected controls. in lytic infections, the rate of host transcription increases ... | 1979 | 390166 |
| constitutive mutation of cysjih operon in a cysb deletion strain of salmonella typhimurium. | in a cysb deletion strain a new mutation, denoted cys-2332 was isolated, which causes the constitutive expression of the cysjih operon. cys-2332 is closely linked to cysjih and presumably is located in the initiator region of this operon, rendering its expression independent of the cysb gene product and the internal inducer o-acetyl-l-serine. the presence of sulfite reductase (encoded by cysi and cysj) activity in a cysb- cys-2332 double mutant indicates that cysg, which is not linked to cysjih ... | 1979 | 390311 |
| mutagens in coffee and tea. | coffee prepared in the usual way for drinking contains a substance(s) that is mutagenic to salmonella typhimurium ta100 without mammalian microsomal enzymes. one cup of coffee (200 ml) contains mutagen(s) inducing 1.4-4.6 x 10(5) revertants under standard conditions. instant coffee too is mutagenic to ta100 and one cup of instant coffee prepared from 1 g of coffee powder and 200 ml of water induced 5.6-5.8 x 10(4) revertants of ta100. caffeine-free instant coffee also has similar mutagenicity. a ... | 1979 | 390384 |
| interaction between amino-alpha-carboline and amino-gamma-carboline on mutagenicity in salmonella typhimurium. | 1979 | 390389 | |
| mutational studies with diquat and paraquat in vitro. | diquat and paraquat were assayed in the following tests. (1) ames test in salmonella typhimurium (strains ta1535, ta1537, ta1538, ta98 and ta100) with and without rat-liver microsomal fractions. (2) resistance to 8-azaguanine in salmonella typhimurium (strain hisg46, ta92 and ta1535. (3) repair test in salmonella typhimurium (strains ta1538 and ta1978). (4) gene mutations in aspergillus nidulans: 8-ag resistance and methionine suppression (meth a1 locus). (5) lethal recessive damage in aspergill ... | 1979 | 390391 |
| mutagenicity of nitrosamines formed from nitrosation of spermidine. | 5 nitrosamines formed from the nitrosation of spermidine were investigated for mutagenicity using various strains of salmonella typhimurium in the presence and absence of s9 mix. using the plate incorporation method, 3-butenyl-(2-propenyl)-n-nitrosamine, 3-hydroxybutyl (2-hydroxypropyl)-n-nitrosamine, 4-hyroxybutyl-(2-hydroxypropyl)-n-nitrosamine, 4 hydroxybutyl-(3-hydroxypropyl)-n-nitrosamine, and in the liquid test 3-hydroxybutyl-(3-hydroxypropyl)-n-nitrosamine were mutagenic in the absence of ... | 1979 | 390392 |
| mutagenicity of pyrrolizidine alkaloids in the salmonella/mammalian-microsome test. | the mutagenicities of 7 pyrrolizidine alkaloids to salmonella typhimurium ta100 were demonstrated by a modified ames's method. the pyrrolizidine alkaloids found to be mutagenic were clivorine, fukinotoxin, heliotrine, lasiocarpine, ligularidine, lx201 and senkirkine. pre-incubation of these alkaloids with s9 mix and bacteria in a liquid medium was essential for demonstration of their mutagenicities. | 1979 | 390394 |
| liver extract mediated mutagenicity of acrylonitrile. | the mutagenic activity of acrylonitrile vapours towards salmonella typhimurium strains strictly depends upon the presence of a liver postmitochondrial fraction. the reversion rate varies according to the animal species from which the s9 fraction is obtained as well as to the pretreatment of the animals. the comparatively weak activating effect of the microsomal fraction and the inability of both skf525a and carbon monoxide to inhibit the s9 mediated mutagenicity of acrylonitrile (acn) suggest th ... | 1979 | 390766 |
| international spread of multiresistent strains of salmonella typhimurium phage types 204 and 193 from britain to europe. | 1979 | 390851 | |
| toxins of molds from decaying tomato fruit. | among 27 mold isolates from decaying tomatoes, culture filtrates or ethyl acetate extracts of 8 isolates grown in yeast extract-sucrose medium were markedly toxic (mortality, greater than 50%) to brine shrimp larvae. the toxicity of six of these isolates could be attributed to the presence of citrinin, tenuazonic acid, or t-2 toxin. ethyl acetate extracts of five alternaria isolates and one fusarium isolate were mutagenic for salmonella typhimurium strains. in ripe tomatoes inoculated with toxin ... | 1979 | 391152 |
| detection of the carcinogenic nitrofuran derivative vr-6 as a mutagen in the salmonella/microsome test. | the carcinogenic nitrofuran, vr-6, was evaluated for mutagenicity in salmonella typhimurium ta 100 using the plate assay (ames test). the dose-response curve indicated that s. typhimurium ta 100 is a very sensitive genetic indicator for this chemical class and that basepair substitution appears to be the molecular mechanism with vr-6. the results reported here provide evidence, that vr-6 is a directly acting mutagen for s. typhimurium ta 100 and that the chemical is partially deactivated in the ... | 1979 | 391179 |
| the catalytically active form of histidinol dehydrogenase from salmonella typhimurium. | the active-enzyme-sedimentation procedure was used to identify the catalytically competent form of histidinol dehydrogenase (ec 1.1.1.23) isolated from salmonella typhimurium. at ph 9.4 the active species has a sedimentation coefficient s20,w of 5.4s, indicating that the dimer with a mol.wt. of approx. 83 000 is the enzymically active form. | 1979 | 391222 |
| effect of an induced conformational change on the physical properties of two chemotactic receptor molecules. | the physical properties and conformational dynamics of the salmonella typhimurium ribose and galactose receptors have been examined. studies involving circular dichroism, fluorescence, absorption spectroscopy, and sedimentation analysis show that the two receptor proteins have different morphologies and exhibit diverse responses to sugar binding. the ribose receptor lacks both tryptophan and disulfide residues, and the galactose receptor lacks disulfides and has only a single tryptophan residue. ... | 1979 | 391272 |
| specificity of insertion by the translocatable tetracycline-resistance element tn10. | genetic analysis of 131 independent transpositions of the tetracycline-resistance element tn10 from a single site in phage p22 into the histidine operon of salmonella typhimurium reveals that tn10 insertions are not randomly distributed along this chromosomal target. the insertions occur in 22 different "clusters"; insertions within each cluster are very tightly linked in recombination tests. tn10 insertions are not evenly distributed among the identified clusters. the existence of these cluster ... | 1979 | 391640 |
| application of agarose gel electrophoresis to the characterization of plasmid dna in drug-resistant enterobacteria. | a simple gel electrophoresis method has been described for the detection of plasmid dna in bacteria (meyers et al., 1976). we investigated further the problems encountered in using this method for the analysis of plasmids in wild enterobacterial strains. the migration of open circular and linear plasmid dna was examined, since these forms sometimes caused difficulty in the interpretation of the plasmid content of uncharacterized strains. electrophoresis at different agarose concentrations was em ... | 1979 | 392048 |
| formation of dna-damaging and mutagenic activity in the reaction systems containing nitrite and butylated hydroxyanisole, tryptophan, or cysteine. | it was confirmed by the procedure of rec-assay that dna-damaging activities were formed in the reaction systems containing nitrite and phenol derivatives including bha, tryptophan or cysteine under gastric ph conditions. the mutagenic action of the nitrite-bha, nitrite-tryptophan and nitrite-cysteine systems was also tested according to ames' method using salmonella typhimurium ta 1535 and ta 98. the mutagenic activity was observed in the nitrite-tryptophan and nitrite-cysteine systems, though t ... | 1979 | 392055 |
| mutagenicity of fluorene derivatives: a proposed mechanism. | several derivatives of fluorene, a tricyclic, organic molecule, have been found to induce both frameshift mutations and base-pair substitutions in salmonella typhimurium strains developed by ames. comparisons of the mutagenic potency of these derivatives for several strains of salmonella suggest the importance of a carbonyl group substituted at the carbon-9 position of mutagenic derivatives, with respect to mutagenic potency. in this study, we present a feasible mechanism for the interaction of ... | 1979 | 392305 |
| intrahepatic mutagenesis assay: a sensitive method for detecting n-nitrosomorpholine and in vivo nitrosation of morpholine. | an intrahepatic host-mediated mutagenicity assay capable of detecting low levels of n-nitrosomorpholine (nmor) is described. the indicator organism was salmonella typhimurium ta1530 which had been injected intravenously 10 min prior to the administration of the test compound. the bacteria were subsequently recovered from the liver and scored for revertants by standard methods. the lower limit of detectibility of this system for intubated nmor was 0.2 microgram/g body weight. this assay was then ... | 1979 | 392314 |
| the mutagenicity of natural products from marine algae. | 5 polyhalogenated hydrocarbon natural products isolated from the marine red alga plocamium spp. were tested for mutagenicity in the ames reversion assay. all 5 of the compounds induced revertants in salmonella typhimurium strains ta100 and ta1535, indicating the mutational events involved base substitutions. one of the compounds, designated cross-conjugated ketone, was shown to be almost 200 times more effective as a mutagen than was ethyl methanesulfonate. | 1979 | 392317 |
| mutagenicity of anthraquinone and azo dyes in ames' salmonella typhimurium test. | 23 dyes belonging to different chemical classes--anthraquinones, mono- and bis-azo compounds--were tested for their mutagenic activity on ames strains of salmonella typhimurium. 5 dyes induced frameshift mutations. | 1979 | 392318 |
| mutagenicity and metabolism studies on 12 thiuram and dithiocarbamate compounds used as accelerators in the swedish rubber industry. | 12 thiuram and dithiocarbamate compounds used in the rubber industry as accelerators, and to some extent as sources of sulfur, were tested, as well as carbon disulfide, a metabolite found in vivo after dithiocarbamate treatment, for mutagenicity in salmonella typhimurium. a mutagenic effect on the base-substitution-sensitive strains ta1535 and ta100 was found for 7 compounds. the most potent directly acting mutagens were: tetramethylthiuram disulfide (tmtd), zinc dimethyldithiocarbamate (ziram), ... | 1979 | 392319 |
| bovine salmonellosis: experimental production and characterization of the disease in calves, using oral challenge with salmonella typhimurium. | a highly virulent strain of salmonella tyhimurium was given orally to produce disease experimentally in 21 normal colostrum-fed calves 3 to 9 weeks old. the challenge inoculum varied from 10(4) to 10(11) organisms. the disease was characterized by fever, depressed attitude, and decreased appetite. many calves given larger challenge dose levels also had diarrheic feces containing mucus, fibrin, and blood. fecal cultures were positive for salmonella. septicemia occurred in some calves (9 of 15 cal ... | 1979 | 393144 |
| [inflammation and host resistance against bacteria. i.--increased resistance against listeria monocytogenes and salmonella typhimurium in mice, following their treatment with bradykinin, kallidin and methionyl-lysyl-bradykinin (author's transl)]. | mice pretreated with kinins are more resistant to a lethal challenge of listeria monocytogenes. the multiplication of listeria is decreased in the liver and spleen and the blood clearance of salmonella typhi-murium is increased. | 1979 | 393161 |
| evaluation of the immune response directed against the salmonella antigenic factors o4,5 and o9. | a pair of o4,5,12 and o9,12 his(+) sister transductants derived from a virulent salmonella typhimurium parent were used as intraperitoneal and oral challenge strains to determine whether immunity directed against the o9 and o4,5 antigenic components could be detected after immunization with heat-killed vaccines containing one or the other of these antigenic components. challenge with a mixture (ca. 1:1) of the two strains and culturing of livers and spleens at intervals indicated that the o4,5,1 ... | 1979 | 393635 |
| 2-amino-5-methyl-5-hexenoic acid, a methionine analog produced by streptomyces sp. mf374-c4. | 2-amino-5-methyl-5-hexenoic acid (amha), a new methionine analog, was isolated from a fermentation broth of streptomyces sp. mf374-c4 based on its reversal of the effect of n-methyl-n'-nitro-n-nitrosoguanidine (mnng) in a test system that determines the size of growth zones of revertants (his+) of salmonella typhimurium ta1535. amha also inhibited growth of the tester strain in a synthetic medium. these amha activities were abolished by methionine. the incidence of spontaneous streptomycin-resis ... | 1979 | 393683 |