Publications

inhibitory effect of reducing agents on n-acetoxy- and n-hydroxy-2-acetylaminofluorene-induced mutagenesis.	the effect of cysteine (alpha-amino-beta-mercaptopropionic acid) on the mutagenic activities of the proximate carcinogen, n-hydroxy-2-acetylaminofluorene, and the ultimate carcinogen, n-acetoxy-2-acetylaminofluorene, was examined by estimating the frequency of his+ revertants of salmonella typhimurium. nontoxic concentrations of cysteine significantly reduced the formation of revertants when it was applied concurrently with the two carcinogens. cysteine showed no detectable effect on mutagenesis ...	1978	346207
selection of salmonella typhimurium mutants with altered serine transhydroxymethylase regulation.	in salmonella typhimurium the glya gene product, serine transhydroxymethylase (e.c. 2.1.2.1.; l-serine:tetrahydrofolate-5,10-hydroxymethyltransferase) is responsible for the interconversion of serine and glycine. this reaction also provides the cell with one-carbon units from the 5,10-methylene-tetrahydrofolate formed during glycine synthesis. despite the importance of this enzyme, however, no mutants in which its regulation has been specificially altered have been isolated. to isolate such muta ...	1978	346438
influence of the growth phase and fimbriae on the gradient elution of salmonella typhimurium from deae-cellulose.		1978	346548
a survey of argentine and lebanese bone for salmonellas with particular reference to the isolation of salmonella typhimurium.		1978	346551
isolation and characterization of mutants of the plasmid pkm101 deficient in their ability to enhance mutagenesis and repair.	a screening procedure was developed for identifying mutants of the plasmid pkm101 no longer capable of enhancing mutagenesis. the test was based on the large pkm101-mediated increase in the number of gal+ papillae observed on colonies of salmonella typhimurium gal mutants plated on tetrazolium-galactose plates in the presence of a mutagen. the pkm101 mutant plasmids transferred normally, were stably maintained in cells, caused normal levels of ampicillin resistance, and still imparted sensitivit ...	1978	346562
permease-specific mutations in salmonella typhimurium and escherichia coli that release the glycerol, maltose, melibiose, and lactose transport systems from regulation by the phosphoenolpyruvate:sugar phosphotransferase system.	several carbohydrate permease systems in salmonella typhimurium and escherichia coli are sensitive to regulation by the phosphoenolpyruvate:sugar phosphotransferase system. mutant salmonella strains were isolated in which individual transport systems had been rendered insensitive to regulation by sugar substrates of the phosphotransferase system. in one such strain, glycerol uptake was insensitive to regulation; in another, the maltose transport system was resistant to inhibition; and in a third ...	1978	346569
transmembrane permeability channels in vesicles reconstituted from single species of porins from salmonella typhimurium.	aggregates of the "major" outer membrane proteins, "porins," of salmonella typhimurium form diffusion channels in reconstituted vesicle membranes. the aggregate consists of three species of porins with apparent molecular weights of 34,000, 35,000, and 36,000 when active aggregates are subjected to sodium dodecyl sulfate-acrylamide gel electrophoresis after heating in the presence of sodium dodecyl sulfate (nakae, j. biol. chem. 251:2176-2178, 1976). single species of porins were isolated by solu ...	1978	346571
role of murein lipoprotein in morphogenesis of the bacterial division septum: phenotypic similarity of lkyd and lpo mutants.	phenotypes were compared in two different classes of mutants with defects in murein-lipoprotein (lkyd mutants of salmonella typhimurium and an lpo mutant of escherichia coli). both mutations are associated with the same triad of phenotypic abnormalities, consisting of defective formation of the division septum, leakage of periplasmic proteins during growth, and increased sensitivity to several unrelated external toxic agents. the abnormality in septum formation consists of a defect in invaginati ...	1978	346575
the mutagenicity of heterocyclic n-nitrosamines for salmonella typhimurium.	14 carcinogenic and noncarcinogenic heterocyclic n-nitrosamines were evaluated for mutagenicity to salmonella typhimurium ta-1535, which responds to mutagens inducing base-pair substitutions. both suspension and plate tests were used, with mouse and rat liver in vitro metabolic activation systems. all carcinogenic nitrosamines showed a positive response in at least one test system, as did the noncarcinogens. in general, the mutagenic responses obtained with mouse liver were equal to, or greater ...	1978	347283
genetic activity of allyl chloride.	allyl chloride (3-chloroprene) is mutagenic for salmonella typhimurium and it induces gene conversions in saccharomyces cerevisiae. it also displays dna-modifying activity for e. coli. this is in contrast to a recent study which reported its lack of genetic activity for salmonella typhimurium.	1978	347285
the mutagenicity of n-nitrosopiperidines for salmonella typhimurium.		1978	347286
tinidazole (tnz) ethyl[2-(2-methyl-5-nitro-1-imidazolyl) ethyl]sulphone) is mutagenic in a salmonella typhimurium assay.		1978	347287
the identification of the trna substrates for the supk trna methylase.	purified preparations of the trna methylase deficient in supk strains of salmonella typhimurium transfer methyl groups from s-adenosylmethionine (sam) to at least two trna species, an alanine trna and a serine trna. the identity of the trna substrates for this enzyme was determined by a change in the elution position of the methyl-labeled trna from bnd-cellulose columns before and after aminoacylation with a specific amino acid followed by derivatization of the free primary amino group with phen ...	1978	347399
detection of salmonella typhimurium infection of chickens.	the serological response of two groups of chickens was followed by three techniques after experimental infection of one group with salmonella typhimurium. results obtained illustrate the greater sensitivity of the microantiglobulin (coombs) test over more conventional methods for detecting salmonella agglutinins. the possibilities of the diagnostic use of the microantiglobulin test in the field are discussed.	1978	347688
salmonella serotypes isolated from the aquatic environment (wabash river, indiana, 1973-1976).	during 1973-1976, 833 isolations of salmonellae were made from the aquatic biosphere of the wabash river, lafayette, ind. of the isolants, 643 were definitively serotyped. salmonella typhimurium represented 34.4% of the cultures. salmonella eimsbuettel previously had not been recognized in indiana. a total of 35 serotypes and 1 untypable group c1 was obtained from the aquatic samples, ie, river water, river bottom sediment, fish, and mussels. most of the isolants were presumed to be of human ori ...	1978	347997
lack of mutagenicity to salmonella typhimurium of some fusarium mycotoxins.	the mutagenicity of eight fusarium toxins (mono-, di-, and triacetoxyscirpenol, t-2 toxin, deoxynivalenol, 3-acetyl-deoxynivalenol, zearalenone, and moniliformin) and of two positive controls (aflatoxin b1 and sterigmatocystin) to histidine-requiring strains ta 98, 100, 1535, and 1537 of salmonella typhimurium was tested both with and without metabolic activation. both aflatoxin b1 and sterigmatocystin, but none of the eight fusarium toxins, were mutagenic to s. typhimurium. the lack of mutageni ...	1978	348106
an epizootic of salmonella typhimurium var. copenhagen in broilers and the use of cultured chicken interestinal flora for its control.	1. an epizootic caused by salmonella typhimurium var. copenhagen and occurring on the farms of one company was examined with the following factors in mind: the spread of the epizootic, the infection rate of the flocks and the role of the food, hatchery and parent stock. 2. a microbiological technique was used the aim of preventing infection on the farms. 3. the method of control was not as effective the field as in the laboratory; the possible reasons for this are discussed.	1978	348270
[specific mutagenic effectiveness of 1,4-bis-diazoacetylbutane in relation to individual genes].	a selective effect of 1,4-bis-diazoacetylbutane (dab) with respect to individual genes is observed when studying its mutagenic action on bacterial strains. escherichia coli and salmonella typhimurium. the frequency of mutations to thr+ exceeded in three orders the background of spontaneous variability for this marker. no induced mutations to trp+ and his+ leu+, which might be the result of transition, transversions, suppressor mutations and frame shift mutations, were detected. mutagenic effect ...	1977	348566
[reparation of the damages induced by uv light in salmonellae].	the survival of salmonella typhimurium wild type strains after uv-irradiation is studied. it is demonstrated that many of these are more sensitive to uv-irradiation than escherichia coli of the wild type. alkaline sucrose density gradient centrifugation has demonstrated a deficiency of these strains in normal excision repair of uv-damaged dna. this deficiency is not a feature of salmonella genus, because a strain is found of the same resistance and reparation ability as e. coli wild type strain.	1977	348575
mutagenicity of nitrosourea compounds for salmonella typhimurium.	the nitrosourea derivatives 1,3-bis(2-chloroethyl)-1-nitrosourea (nsc-409962), 1-(2-chloroethyl)-3-cyclohexyl-1-nitrosourea (ccnu; nsc-79037), 1-(2-chloroethyl)-3-(4-methylcyclohexyl)-1-nitrosourea (me-ccnu; nsc-95441), and 1-methyl-1-nitrosourea (mnu; nsc-23909) were screened for mutagenic potential with salmonella typhimurium strains g46 and ta1530 in vitro and in vivo. alu were also mutagenic in the host-mediated assay. four additional chemotherapeutic nitrosoureas were tested in vitro, three ...	1978	349171
oral administration of neomycin to chickens experimentally infected with salmonella typhimurium.	groups of healthy chickens with a light experimental salmonella typhimurium infection were fed on a diet containing 225 g per ton (1016 kg) of neomycin for two days. this brought about only a slight reduction in the incidence of chickens that were excreting s typhimurium in their faeces. examination of caecal contents two days after the cessation of treatment revealed the neomycin had not had any effect in eliminating infection. in one experiment, the neomycin administration resulted in the emer ...	1978	349853
allosteric inhibition and catabolite inactivation of purified biodegradative threonine dehydratase of salmonella typhimurium.		1978	350274
mutagenicity of several classes of antitumor agents to salmonella typhimurium ta98, ta100, and ta92.	the mutagenic activities of antitumor agents, including 5 antibiotics, 19 antimetabolites, 5 alkylating agents, 2 alkaloids, 1 enzyme, and 1 adrenal steroid hormone, were tested on salmonella tyhimurium ta100, ta98, and ta92. four of these, busulfan, carbazilquinone, 1-(4-amino-2-methylpyrimidine-5-yl)methyl-3-(2-chloroethyl)-3-nitrosourea hydrochloride, and pipobroman were shown for the first time to be mutagenic. further, the known mutagenicities of five others, daunomycin hydrochloride, adria ...	1978	350383
1,2-dihydro-1,2-dihydroxy-5-methylchrysene, a major activated metabolite of the environmental carcinogen 5-methylchrysene.	the metabolic activation of the environmental carcinogen 5-methylchrysene was studied by combining high-pressure liquid chromatographic analysis of metabolites formed in vitro with assays of these metabolites for mutagenic activity toward salmonella typhimurium. metabolites were formed by incubation of 5-methylchrysene with the 9000 x g supernatant from aroclor-treated rat livers. with the use of reverse-phase columns, the metabolites were resolved into nine peaks, a to i. each peak was collecte ...	1978	350385
the acceptor for polar head groups of the lipid a component of salmonella lipopolysaccharides.	we describe here experiments which determine at which stage in the lipid a biosynthesis the polar head groups 4-aminoarabinose, phosphorylethanolamine and 3-deoxy-d-manno-octulosonic acid are transferred to the diphosphorylated glucosamine backbone of the lipid a structure. use was made of a conditional lethal mutant of salmonella typhimurium (ts1) which is defective in the synthesis of 3-deoxy-d-manno-octulosonic acid 8-phosphate and accumulates under nonpermissive conditions an underacylated l ...	1978	350584
[exerimental study of enterotoxic activity in some strains of salmonella typhimurium: observations on the model of adp-induced platelet aggregation].	in a previous report it has been shown that enterotoxin preparations (cholera and e. coli) able to activate adenylatecyclase system, abrogated platelet aggregation induced by adp. in the present study the same experimental model has been applied to some purified filtrates from salmonella typhimurium strains. preparations from 986 and tlm (invasive strains causing also fluid secretion) interfere with platelet aggregation, while 1027 strain (invasive but not evoking fluid secretion) didn't show su ...	1977	350683
isolation of salmonella typhimurium from cephalhematoma and osteomyelitis.		1978	350769
characterization of a salmonella typhimurium hisu mutant defective in trna precursor processing.	the da11 mutant of salmonella typhimurium, originally isolated as derepressed for the histidine operon, carries a temperature-dependent alteration in a nucleolytic enzyme specifically involved in the maturation of trna. as a consequence of this alteration, no detectable synthesis of any mature trna species occurs in da11 upon shift at 43 degrees c, whereas many trna precursors, whose sizes range between 80 and 750 nucleotides, do accumulate. kinetic studies on the synthesis and processing of the ...	1978	350829
immunochemistry of salmonella o-antigens: preparation of an octasaccharide-bovine serum albumin immunogen representative of salmonella serogroup b o-antigen and characterization of the antibody response.	the o-antigenic polysaccharide of phenol-water extracted salmonella typhimurium (o antigens 4, 12) lipopolysaccharide was enzymatically cleaved by phage p22 endorhamnosidase. an octasaccharide with the (formula: see text) structure gal-man-rha-gal-man-rha was isolated and shown to retain the o-antigen 4 specificity of the native polysaccharide. after oxidation of the terminal reducing rhamnose residue to the corresponding aldonic acid, the octasaccharide was covalently linked to bovine serum alb ...	1978	351058
nucleotide sequence of the promoter--operator region of the tryptophan operon of salmonella typhimurium.		1978	351192
rna polymerase interaction at the promoter--operator region of the tryptophan operon of escherichia coli and salmonella typhimurium.		1978	351193
comparison of the nucleotide sequences of the initial transcribed regions of the tryptophan operons of escherichia coli and salmonella typhimurium.		1978	351195
screening of safrole, eugenol, their ninhydrin positive metabolites and selected secondary amines for potential mutagenicity.	the mutagenicity of safrole, eugenol, the secondary amines, with which they combine during metabolism, and the ninhydrin positive urinary metabolites of safrole and eugenol was tested. the panel of tests included the direct bacterial assay, a microsomal mutagenesis assay and a host-mediated assay. with the direct bacterial assay employing four mutant strains of salmonella typhimurium (ta1530, ta1531, ta1532, ta1964), all the compounds gave negative results. in the microsomal mutagenesis assay, ...	1978	351383
mutagenicity of n-nitrosopiperazine derivatives in salmonella typhimurium.	mutagenicity of several nitroso derivatives of piperazine was assayed using histidine auxotrophic strains of salmonella typhimurium. nitroso derivatives of piperazine required metabolic activation with preference to phenobarbital induced rat-liver microsomal enzymes. we observed a good correlation between a positive effect in the mutation assay and the carcinogenic potency of the compound. even though our results are not in complete agreement with earlier published work using several microbial m ...	1978	351385
potentiation, desensitization, and inversion of response in bacterial sensing of chemical stimuli.	behavior patterns of chemotactic mutants of salmonella typhimurium were compared to those of the wild type by using the quantitative tumble frequency assay. some cheu mutants were completely inverted in their responses--e.g., attractants produce responses expected for repellents and repellents produce responses expected for attractants. still others swam smoothly and did not respond to any stimuli. mutants of other complementation groups were found to exhibit exact additivity or potentiation in ...	1978	351616
[atypical strains of salmonella typhimurium isolated during hospital infection].		1978	352044
a mutant of escherichia coli which accumulates large amounts of coproporphyrin.	a mutant of escherichia coli which accumulates a large amount of coproporphyrin, presumably because of a block in heme biosynthesis, has been isolated after nitrosoguanidine mutagenesis. on rich media, the mutant forms colonies which give bright orange fluorescence when illuminated with ultraviolet light. the mutant appears to be similar to a salmonella typhimurium mutant, deficient in uroporphyrinogen iii cosynthase, described by sasarman and desrochers ((1976) j. bacteriol. 128, 717--721). a s ...	1978	352406
genetic instability in auxotrophs of salmonella typhimurium requiring cysteine or methionine and resistant to inhibition by 1,2,4-triazole.	triazole-resistant (trz(r)) derivatives of six cysteine- or methionine-requiring (cym(-)) mutants of salmonella typhimurium were isolated. some of the derivatives of each mutant (cts) were prototrophic, i.e., cym(-) was suppressed. in every case suppression was initially unstable, cym(-) auxotrophs being segregated at high frequency, although trz(r) was stable. after several subcultures on selective medium, cts strains were classified as either persistently unstable or stabilized. the unstable s ...	1978	352798
the nature of genetic instability in auxotrophs of salmonella typhimurium requiring cysteine or methionine and resistant to inhibition by 1,2,4-triazole.	we tested the hypothesis that unstable suppression of auxotrophy in triazole-resistant derivatives of cym- mutants of salmonella typhimurium is due to reversible insertion at the cym- site of genetic material originating in the cysalkptshi region. we have shown that the unstable phenotype was co-transducible with markers in the cyscdhij region. the suppression of the cym phenotype was reca dependent and frequencies of segregation were affected by uv irradiation. restored enzyme activity in suppr ...	1978	352799
[intergeneric conjugational hybridization of escherichia coli and salmonella typhimurium. 1. obtaining a salmonella hybrid possessing greater recipient activity in crosses with escherichia coli].	intergeneric hybrids were selected from mating hfrh escherichia coli with f- salmonella typhimurium. the hybrid obtained from e. coli leu+ and pro+ genes possessed the increased recipient ability in the mating with e. coli hfrr1 (o--ilv--mete--ara). this hybrid lacked the ability to restrict the phage p1 dna propagated on e. coli k-12. the replacement of mutated uvra gene of salmonella for uvra+ gene of e. coli restore uvr+ phenotype of salmonella mutant.	1977	352802
[mutagenic activity of dioxydine].	a previous evaluation of mutagenic activity of some drugs and perspective substances is carried out using indicator microorganisms. the mutagenicity of dioxydine, a drag with discovered antibacterial activity, is investigated. dioxydine is shown to induce reversions in mutant of salmonella typhimurium ta-1950, the indicator strain which demonstrates mutagenic activity of agents, producing mutations of base pair substitution type. dioxydine proved to affect logariphmiically growing bacterial cult ...	1978	352806
production and partial purification of salmonella enterotoxin.	by using a strain of salmonella typhimurium, we detected the presence of an enterotoxin, as determined by the rabbit ileal loop assay, in various complex and defined media. the enterotoxin was concentrated by ultrafiltration of culture supernatant fluids and eluted in and adjacent to the void volume of a sephadex g-100 column. this suggested that the enterotoxic factor was of a relatively high molecular weight, and additional evidence indicated it was heterogeneous in size. further chromatograph ...	1978	352941
bacteriophage p22 is not a likely probe for zones of adhesion between the inner and outer membranes of salmonella typhimurium.	thin-section electron micrographs of plasmolyzed salmonella typhimurium infected with bacteriophage p22 demonstrated that phage adsorbed to cells over sites of inner- and outer-membrane contact. efforts were made to isolate such adsorption sites by infection of cells with 35s- and 32p-labeled phage and by separation of the membranes on sucrose gradients. at 37 degrees c, about 75% of the 35s radioactivity could be recovered in a region of intermediate density between the inner and outer membrane ...	1978	353032
mutagenic action of triose reductone and ascorbic acid on salmonella typhimurium at 100 strain.		1978	353232
linkage map of salmonella typhimurium, edition v.		1978	353483
genetic control of defective cell shape and osmotic-sensitivity in a mutant of salmonella typhimurium.		1978	353491
arginine regulon control in a salmonella typhimurium--escherichia coli hybrid merodiploid.	the regulation of synthesis of arg enzymes was studied in a hybrid merodiploid in which an episome of escherichia coli carrying the argr+ allele was transfered to salmonella typhimurium argr strain. the arg enzyme levels of the hybrid merodiploid were compared to that found in argr and argr+ haploids of s. typhimurium. the results showed that repression of synthesis of arg enzymes was effected through the introduction of the e. coli argr+ allele but significant quantitative differences of arg en ...	1978	353519
microbial assays for mutagenicity: a modified liquid culture method compared with the agar plate system for precision and sensitivity.	a microbial assay system for mutagenicity was developed in which bacterial cells divided in liquid culture. the statistical and practical problems associated with dividing cells were avoided or reduced, whilst the advantages in precision and reliability resulting from the determination of mutation per colony-forming unit (survivor) and of separating the mutation and selection systems were retained. seven mutagens, two of which required microsomal activation, were evaluated by this liquid-medium ...	1978	353542
analytical and biological analyses of test materials from the synthetic fuel technologies. i. mutagenicity of crude oils determined by the salmonella typhimurium/microsomal activation system.	we have assayed the mutagenicity of crude industrial products and effluents with the salmonella/microsomal activation system. test materials (crude products from coal-conversion processes and natural crude oils) were initially fractionated into primary classes by liquid--liquid extraction and then further fractionated by column chromatography. prescreening was accomplished over a wide concentration range with the ames tester strains. active fractions (mainly the neutral fractions containing poly ...	1978	353548
microbiological mutagenicity studies of pesticides in vitro.	14 pesticides were tested as pure compounds for the induction of point mutations in four strains of salmonella typhimurium--ta1535, ta1536, ta1537 and ta1538--in the presence and in the absence of rat-liver microsomal fractions and for the induction of resistance to low concentrations of streptomycin in the filamentous bacterium, streptomyces coelicolor. the technique used was essentially the so-called "spot test". the pesticides investigated were: aminotriazole, benomyl, captafol, captan, dichl ...	1978	353549
[post-salmonella rheumatism: case report].	a twenty seven year old man had polyarthritis following diarrhoea due to salmonella typhimurium. the role of the salmonella infection in the pathogenesis of this joint problem would appear to be confirmed by the detection of the organism on stool culture and a positive reaction for specific antigens in the blood. the arthritis was cured in six weeks under the influence of non-steroid anti-inflammatory agents.	1978	353717
nonmutagenic action of cannabinoids in vitro.	under the specific conditions reported for the separate tests delta9-tetrahydrocannabinol (thc) did not elicit a mutagenic response in microbial and eukaryotic in vitro test systems. thc treatment to histidine auxotrophs of salmonella typhimurium strains ta 98 (susceptible to frame shift mutation) and ta 100 (susceptible to base pair substitution) were investigated. analysis for possible revertance in the presence and absence of s9 microsomal activation system indicated an absence of induction o ...	1978	353830
detection of mutagens produced by fungi with the salmonella typhimurium assay.	forty-one fungal isolates (one isolate per species) representing common plant pathogens and food crop contaminants were grown on sterile, polished rice and assayed for mutagenic activity in the salmonella typhimurium-microsome system. initially, single doses of aqueous and chloroform extracts of the moldy rice were assayed against the ta100 tester strain by incorporating extracts into the growth medium and by applying small quantities on disks placed on the agar surface. suspected activity was e ...	1978	354528
survival of a salmonella typhimurium experimental contaminant during cooking of beef roasts.	twenty-one raw boneless beef roasts were experimentally injected with 2 x 10(7) cells of a nalidixic acid-resistant strain of salmonella typhimurium per roast. contaminated roasts were cooked to center internal temperatures of 137.0 to 147.5 degrees f (58.3 to 64.1 degrees c) in a gas-fired pilot plant food-processing oven. viable experimental contaminants were recovered from two core samples of the 21 roasts (one cooked to 137.0 degrees f [58.3 degrees c] and one cooked to 141.5 degrees f [ca 6 ...	1978	354529
[observed metabolic changes in the polymorphonucleocytes and macrophages of guinea pigs injected with salmonella typhimurium s neurotoxin].		1977	354587
an evaluation of 6 short-term tests for detecting organic chemical carcinogens.	a number of tests have been described which are thought to be capable of identifying carcinogens without using the actual induction of cancer as an endpoint. this study compared the performance of 6 such tests on a selection of 120 organic chemicals. the tests studies were: (1) mutation of salmonella typhimurium; (2) cell transformation; (3) degranulation of endoplasmic reticulum; (4) sebaceous gland suppression; (5) tetrazolium reduction and (6) subcutaneous implant. a further 4 tests were exam ...	1978	354672
mutagenic and recombinogenic effects of the antitumor antibiotic anthramycin.	anthramycin, one of the pyrrolo(1,4)benzodiazepine antibiotics with potent antitumor activity, was tested for its effects on a number of genetic parameters. the results show that this antibiotic is nonmutagenic in the ames strains of salmonella typhimurium while mutagenic in only one and antimutagenic in the rest of the genes tested in the eukaryotic organism saccharomyces cerevisiae. the antibiotic is, however, a potent recombinogen inasmuch as it induced mitotic crossing over, mitotic gene con ...	1978	354779
dietary lipid-dependent activation of the carcinogen n-2-fluorenylacetamide in rats as monitored by salmonella typhimurium.		1978	354780
activation of carcinogens and mutagens by rat colon mucosa.	colon mucosal cells can catalyze the activation of precarcinogens to mutagenic metabolites without the intermediacy of intestinal bacteria as shown in a mutagenesis assay system composed of salmonella typhimurium strain ta100 and the 9000 x g supernatant fraction of rat colon mucosal cells. pretreatment of rats with beta-naphtoflavone increased the activation of 2-aminoanthracene 10- to 20-fold and the activation of benzo(a)pyrene 4-fold. pretreatment of rats with aroclor 1254 doubled the activa ...	1978	354782
[intergeneric conjugational crossing of escherichia coli with salmonella typhimurium. ii. transfer of a pola1 mutation from escherichia coli to salmonella typhimurium and its phenotypic expression in the salmonella genome].	the escherichia coli structural gene for dna polymerase i was inserted into salmonella typhimurium chromosome by conjugal transfer. the genetic analysis of p1-mediated transduction of obtained hybrid showed that pola gene is located in it between mete and rha loci and is cotransduced with mete (about 50%) and rha (12%). the phenotypic properties of pola1 hybrid e. colixs. typhimurium concerning uv-mms-ng and gamma-ray sensitivity are similar to the pola1 mutants of e. coli.	1977	355054
inducible reactivation and mutagenesis of uv-irradiated bacteriophage p22 in salmonella typhimurium lt2 containing the plasmid pkm101.	the inducible (weigle) reactivation of uv-irradiated bacteriophage p22 has been examined on strains of salmonella typhimurium with and without the mutagenesis-enhancing plasmid pkm101. a large inducible reactivation was observed in the plasmid-containing strain, but only a small response was observed in the strain lacking the plasmid. an increased frequency of clear-plaque mutants was detected among the survivors. the efficiencies of the plasmid-mediated and cellular repair processes have been d ...	1978	355224
salmonella typhimurium mutants lacking protease ii.	mutants of salmonella typhimurium lacking protease ii, an endoprotease with trypsin-like specificity, have been isolated. these mutants can be identified by using the chromogenic substrate n-methyl-n-p-toluenesulfonyl-l-lysine beta-naphthyl ester to screen colonies growing on agar for the presence of the enzyme. all of the mutations isolated map at locus tlp (typsin-like protease) which is cotransducible (approximately 1%) using phage p1 with tre (trehalose utilization) at approximately 58 min o ...	1978	355236
outer membrane of gram-negative bacteria. xviii. electron microscopic studies on porin insertion sites and growth of cell surface of salmonella typhimurium.	salmonella typhimurium contains three "major proteins" or "porins" (34k, 35k, and 36k) in the outer membrane. a mutant strain producing only the 35k porin was first grown in media containing high concentrations of nacl to "repress" the porin synthesis and then was shifted into a medium without nacl. the newly made porin molecules were then labeled with the ferritin-coupled antibody at various times after the shift, and the samples were examined by whole-mount, freeze-etching, and thin-section el ...	1978	355240
detection of mutagenicity of the colon carcinogen 1,2-dimethylhydrazine by the host-mediated assay and its correlation to carcinogenicity.	mutagenic potential of 1,2-dimethylhydrazine (dmh) was investigated in the host-mediated assay with mice used as hosts. this assay revealed potent mutagenicity of this colon carcinogen for salmonella typhimurium g46. the mutagenicity of dmh was inhibited by pretreatment of mice with disulfiram. in addition, mouse strain and sex differences influenced the mutation induction by dmh: mutation induction was significantly lower in c57bl/6 mice than in outbred icr mice of either sex and was generally ...	1978	355648
direct demonstration of duplicate tuf genes in enteric bacteria.	radioactive tuf mrna was used to detect the tuf gene in bacterial dna that had been digested by various restriction endonucleases. both the k-12 and the b strains of escherichia coli contain two tuf genes, but no more than two. salmonella typhimurium also contains duplicate tuf genes.	1978	356046
[distribution and characteristics of the r factors in e. coli isolated from poultry].	it has been demonstrated that escherichia coli organisms isolated from birds in the district of haskovo are up to 65 per cent resistant to drugs. it has been experimentally shown that the genetic determinants of resistance to chemotherapeutics are transferred via conjugation. the possibility of transferring r-factors from escherichia coli to salmonella typhimurium points to one of the routes for the occurrence of drug resistance in salmonella bacteria.	1978	356413
[effect of low temperatures on the count and virulence of salmonellae in slaughtered poultry].	studied was the effect of shock freezing at -34 degrees c and the storing of slaughtered birds at -18 degrees c up to six months on the survival and the change in the virulence of salmonella typhimurium, s. meleagridis, and s. gallinarum-pullorum. it was established that the number of the tested salmonella species decreased steadily, however, no complete devitalizing was attained. the salmonella count was most intensely reduced in the first fifteen days of storing. most resistant to the effect o ...	1978	356414
cellular response in salmonella typhimurium-infected mice: evaluation of salmonella receptors of b lymphocytes.	the cellular response in the course of experimental infection with salmonella typhimurium was studied in mice. t cells were detected by the presence of theta-antigen, b cells by the binding of fluorescent immunoglobulins, and cells with receptors by labeled salmonella binding. lymphocytes were from spleen and lymph nodes. results have been divided into three groups: group a, including mice with slight symptomatology; group b, including those with serious infection symptomatology; and group c, in ...	1978	357283
mapping of the heme locus in salmonella typhimurium.	a new type of heme-deficient mutant was isolated in salmonella typhimurium by neomycin selection. the mutant was deficient in uroporphyrinogen decarboxylase activity, coded by the heme gene. the heme gene was located between the genes rif and thi at 128 min on the chromosomal map of s. typhimurium.	1978	357418
a model for the adsorption of phage p22 to salmonella typhimurium.	a new model for the adsorption of bacteriophage p22 to its host salmonella typhimurium is proposed. the main feature of this model is that only three of the six tail proteins found on the mature phage function during adsorption. this model explains why there is a difference in the specific endoglycosidase activity of the tail protein of mature virions as opposed to unattached tail protein. it also accounts for the cubic relationship between p.f.u. and tail protein concentration in in vitro assem ...	1978	357683
dctp deaminase from salmonella typhimurium.		1978	357902
thymidine phosphorylase from salmonella typhimurium.		1978	357903
preferential uptake of thymidine by thymineless enterobacteria: its significance in dna labelling.	minimum satisfactory concentrations of thymine and thymidine were determined for the growth of a high thymine-requirng (thy) mutant to escherichia coli strain j5-3. cultures were then grown in the presence of these concentrations of non-radioactive ('cold') pyrimidine together with 5 microci/ml [methyl-3h)thymine, or [methyl-3h)thymidine (specific activities 5 ci/m mole), and the uptake of radioactivity into ice cold trichloroacetic acid insoluble material determined. by far the most efficient l ...	1977	357930
a protein methylesterase involved in bacterial sensing.	a protein methylesterase has been identified in soluble extracts of salmonella typhimurium and escherichia coli. this enzyme catalyzes the hydrolysis of gamma-glutamyl methyl ester residues from membrane-bound 60,000-molecular weight proteins that are essential for chemotaxis. analyses of methylesterase activity in a variety of chemotactically defective strains suggest that the methylesterase is a product of the chex gene in salmonella and the cheb gene in e. coli. in addition, the chet gene pro ...	1978	358191
[food poisoning caused by salmonella typhimurium].		1978	358303
eidemiological aspects of an outbreak of salmonellosis in sheep.	an outbreak of salmonellosis caused by salmonella typhimurium occurred in a lambing flock where management factors and fostering movements were responsible for spread within the group and to farm personnel and their families. possible sources of the infection are discussed.	1978	358546
vinyl carbamate as a promutagen and a more carcinogenic analog of ethyl carbamate.	vinyl carbamate was much more active (10 to 50 times) than ethyl carbamate for the initiation of skin tumors and for the induction of lung adenomas in mice. vinyl carbamate was also mutagenic to salmonella typhimurium ta 1535 and ta 100 in the presence of reduced nicotinamide adenine dinucleotide phosphate-fortified rat or mouse liver mitochondrial supernatant fractions. this mutagenic activity was inhibited strongly by cytochrome p-450 inhibitors. no mutagenic activity was observed for vinyl ca ...	1978	359128
immunization of calves against salmonellosis.	salmonella typhimurium bacterins, containing adequate antigenic mass, protected calves against clinical signs of salmonellosis and death. protection against salmonellosis was correspondingly reduced when the bacterin was diluted 1:10 and 1:100. a mouse protection test revealed that 17 of 18 (94%) of the s typhimurium-containing bacterin serials produced in 1977 stimulated adequate immunity.	1978	359522
kinetic analyses of the sugar phosphate:sugar transphosphorylation reaction catalyzed by the glucose enzyme ii complex of the bacterial phosphotransferase system.	the sugar phosphate:sugar transphosphorylation reaction catalyzed by the glucose enzyme ii complex of the phosphotransferase system has been analyzed kinetically. initial rates of phosphoryl transfer from glucose-6-p to methyl alpha-glucopyranoside were determined with butanol/urea-extracted membranes from salmonella typhimurium strains. the kinetic mechanism was shown to be bi-bi sequential, indicating that the enzyme ii possesses nonoverlapping binding sites for sugar and sugar phosphate. bind ...	1978	359550
evidence for protein kinase activities in the prokaryote salmonella typhimurium.	evidence for phosphorylation of proteins by protein kinases has been found in salmonella typhimurium despite previous indications that protein kinase action is absent in prokaryotes. at least four proteins have been found to be phosphorylated. serine and threonine phosphates have been isolated from acid hydrolysates of these proteins after in vivo and in vitro labeling. the kinases do not phosphorylate histones, casein, or phosvitin. it would appear that phosphorylation as a regulatory control e ...	1978	359551
cysteine synthetase from salmonella typhimurium lt-2. aggregation, kinetic behavior, and effect of modifiers.		1978	359557
correlation of phaga type, biotype and source in strains of salmonella typhimurium.	a series of 2092 cultures of salmonella typhimurium isolated from human, animal and other sources in 57 countries were differentiated into 204 phage types and 19 primary and 147 full biotypes. different biotypes belonged to the same phage type and different phage types to the same biotype, so the combination of typing methods differentiated strains more finely than either method alone: 574 different ;phage type/biotypes' were distinguished in 1937 cultures belonging to the 204 recognized phage t ...	1978	359703
bacteriophage p22-mediated specialized transduction in salmonella typhimurium: high frequency of aberrant prophage excision.	the temperate bacteriophage p22 mediates both generalized and specialized transduction in salmonella typhimurium. specialized transduction by phage p22 is different from, and less restricted than, the well characterized specialized transduction by phage lambda, due to differences in the phage dna packaging mechanisms. based on the properties of the dna packaging mechanism of phage p22 a model for the generation of various types of specialized transducing particles is presented that suggests gene ...	1978	359827
bacteriophage p22-mediated specialized transduction in salmonella typhimurium: identification of different types of specialized transducing particles.	the temperate bacteriophage p22 mediates both generalized and specialized transduction in salmonella typhimurium. specialized transduction by phage p22 is different from, and less restricted than, the well characterized specialized transduction by phage lambda, due to differences in the phage dna packaging mechanism. phage lysates produced by induction of lysogenic strains contain very high frequencies of supq newd- and proa,b-specialized transducing particles (10(-2)/pfu and 10(-3)/pfu, respect ...	1978	359828
acylaminoacid esterase mutants of salmonella typhimurium.	salmonella typhimurium contains three electrophoretically separable enzyme activities that hydrolyze n-acetyl phenylalanine beta-naphthyl ester (napne). one of these enzymes is an endoprotease, protease i. mutations at a locus apea near pure lead to loss of this enzyme. we have found that n-acetyl leucine alpha-naphthyl ester (nalne) is not hydrolyzed by protease i but is a good substrate for the other two activities. using nalne as a chromogenic substrate to screen colonies growing on agar, we ...	1978	360040
nucleotide sequence of the leader region of the phenylalanine operon of escherichia coli.	the phea structural gene of the phenylalanine operon of escherichia coli is preceded by a transcribed leader region of about 170 nucleotide pairs. in vitro transcription of plasmids and restriction fragments containing the phe promoter and leader region yields a major rna transcript about 140 nucleotides in length. this transcript, phea leader rna, has the following features: (i) a potential ribosome binding site and aug translation start codon about 20 nucleotides from its 5' end; (ii) 14 addit ...	1978	360214
dna sequence from the histidine operon control region: seven histidine codons in a row.	the dna sequence of 250 base pairs preceding the first structural gene of the histidine operon of salmonella typhimurium was determined by the dideoxy chain-termination method. single-stranded dna template was provided by an m13-histidine transducing phage constructed for the purpose by in vitro recombination. the termination site for the histidine leader rna is identified by analogy with the trp operon leader termination sequence, and is 47 nucleotides before the start codon of the first struct ...	1978	360216
relative sensitivities of forward and reverse mutation assays in salmonella typhimurium.	forward mutation to 8-azaguanine resistance and reverse mutation to histidine prototrophy were measured in salmonella typhimurium after treatment with 16 mutagens of both base-substitution and frameshift classes. the two approaches were found to be equisensitive for all 16 mutagens--i.e., induction of significant mutation occurred at similar concentrations in the forward mutation assay and in the most sensitive of the five ames tester strains.	1978	360221
mutagenic activity of hymenovin in salmonella typhimurium: association with the bishemiacetal functional group.		1978	360487
mutagenicity of acrylonitrile.	incubation of salmonella typhimurium strains in an atmosphere of 0.2% gaseous acrylonitrile increased the numbers of his+ revertants/plate only in the presence of a fortified s9 liver fraction. the mutagenic effect was particularly pronounced with strains ta1530, ta1535 and ta1950 and much weaker with strains ta100, ta98 and ta1978. the results of bacterial fluctuation tests confirmed the necessity of the presence of s9 mix and showed the particular sensitivity of ta1530. the reversion rate vari ...	1978	360488
toxicological model for a two-acid system.	lactic and acetic acids were determined to be slightly synergistic in their inhibitory interrelationship against salmonella typhimurium with the use of a modified toxicological model.	1978	360990
citrate transport in salmonella typhimurium.		1978	360994
transport of c4-dicarboxylic acids in salmonella typhimurium.		1978	360995
spread of multiresistant strains of salmonella typhimurium phage types 204 and 193 in britain.		1978	361157
purification and characterization of a trna methylase from salmonella typhimurium.	a trna methylase, in which supk strains of salmonella typhimurium are deficient, was purified from strain lt2 and characterized. column chromatography of protein extracts from wild-type cells on phosphocellulose, diethylaminoethyl-sephadex a-50, and hydroxlapatite resulted in an enzyme that was estimated to be about 50% pure. trna from s. typhimurium which had been incubated at ph 9.0 served as a substrate for this methylase. the enzyme has a molecular weight of about 50,000 as estimated by gel ...	1978	361688
biosynthesis of uridine diphosphate n-acetylmannosaminuronic acid in rff mutants of salmonella tryphimurium.	in salmonella typhimurium, three groups of genes located in rfb, rfe, and rff clusters are known to be involved in the biosynthesis of the enterobacterial common antigen. we found that enzymatic synthesis of uridine diphosphate n-acetylmannosaminouric acid, the activated form of a constituent sugar of the common antigen, followed the pathway previously described in escherichia coli (n. ichihara, n. ishimoto, and e. ito, febs lett. 39:46--48, 1974). all of the six rff mutants tested, which fail t ...	1978	361690
major outer membrane protein in salmonella typhimurium induced by maltose.	a maltose-induced major outer membrane protein (the 44k protein) is demonstrated in salmonella typhimurium. this protein resembles the lambda receptor of escherichia coli in its location, induction properties, apparent molecular weight, and association with the peptidoglycan layer of the cell wall. the 44k protein is missing in certain salmonella mal- mutants, which are also missing a protein analogous to the maltose-binding protein of e. coli. thus, these mutants may be defective in the control ...	1978	361696
genetic mapping of tyramine oxidase and arylsulfatase genes and their regulation in intergeneric hybrids of enteric bacteria.	the genes for arylsulfatase (atsa) and tyramine oxidase (tyna) have been mapped in klebsiella aerogenes by p1 transduction. they are linked to gdhd and trp in the order atsa-tyna-gdhd-trp-pyrf. complementation analysis using f' episomes from escherichia coli suggested an analogous location of these genes in e. coli, although arylsulfatase activity was not detected in e. coli. p1 phage and f' episomes were used to create intergeneric hybrid strains of enteric bacteria by transfer of the ats and t ...	1978	361719
investigations on the outer membrane proteins of salmonella typhimurium.	the number, nature and organization of the outer membrane proteins of salmonella typhimurium have not yet been resolved. therefore these proteins were isolated using a concentrated solution of guanidine hydrochloride and studied using different analytical techniques. upon chromatography on sephadex g-200 four fractions were obtained. only the fraction containing a protein of molecular weight 13,000 produced immunoprecipitation reactions with the antisera raised against the whole bacteria. on pol ...	1977	362132
analysis of merodiploids of the cysb region in salmonella typhimurium.		1978	362164