| hepatocarcinogenicity of estragole (1-allyl-4-methoxybenzene) and 1'-hydroxyestragole in the mouse and mutagenicity of 1'-acetoxyestragole in bacteria. | approximately 20% of a dose of estragole, a naturally occurring flavoring agent, was excreted in the urine of outbred male cd -1 mice as a conjuage (presumably the glucuronide) of 1'-hydroxyestragole, estragole and its 1'-hydroxy metabolite caused significant increases in the incidences of hepatocellular carcinomas in male cd-1 mice that received the compounds by sc injection at 1-22 days of age. estragole induced hepatocellular carcinomas by 15 months in 23 and 39% of the mice that received tot ... | 1976 | 187802 |
| comparative effect of methioninyl adenylate on the growth of salmonella typhimurium and pseudomonas aeruginosa. | the bacteriostatic effect of methioninyl adenylate(mamp)--a specific inhibitor of the enzyme methionyl-trna synthetase--was investigated on salmonella typhimurium and pseudomonas aeruginosa. 0.1 mm of this molecule added to the culture, inhibits the growth of s. typhimurium. the inhibition is specifically reversible by 0.1 mm l-methionine. in the same conditions even 1-2 mm mamp has a very slight effect on the growth rate of p. aeruginosa and only during the first two generations. the same obser ... | 1976 | 189717 |
| pyrimidine ribonucleoside monophosphokinase and the mode of rna turnover in bacillus subtilis. | a protein catalyzing the phosphorylation of cmp to cdp was purified and characterized. kinase activity for ump copurified during ammonium sulfate fractionation, deae-cellulose and hydroxylapatite chromatography, and gel filtration on sephadex g-75, the ratios of activities for the two substrates remaining constant. the purified product, possessing both activities was homogeneous as judged by the single band following polyacrylamide gel electrophoresis. the protein showed no kinase activity again ... | 1976 | 189719 |
| outer membrane of salmonella typhimurium. electron spin resonance studies. | the supramolecular structure of the outer membrane of salmonella typhimurium that produces an rc-type lipopolysaccharide was studied by adding spin-labeled fatty acid probes to membranes as well as model bilayers. lipopolysaccharide of this organism apparently formed a bilayer structure in 0.2 m nacl/0.01 m mgcl2, and the electron spin resonance spectra suggested that the motion of the segments of hydrocarbon chains near the carboxyl end was quite restricted even at high temperature; this is pre ... | 1977 | 189812 |
| galactose transport in salmonella typhimurium. | we have studied the various systems by which galactose can be transported in salmonella typhimurium, in particular the specific galactose permease (gp). mutants that contain gp as the sole galactose transport system have been isolated, and starting from these mutants we have been able to select point mutants that lack gp. the galp mutation maps close to another mutation, which results in the constitutive synthesis of gp, but is not linked to galr. growth of wild-type strains on glaactose induces ... | 1977 | 190207 |
| the role of camp in flagellation of salmonella typhimurium. | a mutational alteration either in adenylate cyclase (cya-) or in cyclic-3'5'-amp (camp) receptor protein (crp-) rendered salmonella typhimurium incapable of producing flagella. the amount of mrna specific for flagellin in these mutants was almost negligible when assayed in an in vitro protein synthesizing system. a secondary mutation cfs, partially suppressing the cya- mutation, was identified among the revertants of cya-. a mutation in the same cistron as cfs resulted in a non-flagellate phenot ... | 1976 | 178991 |
| correlation of bacterial mutagenicity and hamster cell transformation with tumorigenicity induced by 2,4-toluenediamine. | in the presence of rat liver microsome enzymes, 2,4-toluenediamine (tda) was mutagenic for several tester strains of salmonella typhimurium. tda induced morphological transformation in an in vitro carcinogenesis system using secondary culture target cells prepared from cryopreserved primary syrian hamster embryo cells. these results now correlate bacterial mutagenicity and in vitro morphological transformation with the reported tumorigenicity of this compound. | 1977 | 196749 |
| hepatic clearance of salmonella typhimurium in silica-treated mice. | scanning electron microscopy demonstrates that crystalline silica destroys liver kupffer cells but has no other obvious deleterious effects on the liver. silica-treated livers still retain the ability to trap large numbers of bacteria perfused through the portal vein even though the rate of clearance is well below normal. in vivo, silica treatment decreases the rate of bacterial clearance from the blood, alters the in vivo organ distribution of cleared bacteria, and decreases the mean lethal dos ... | 1977 | 197004 |
| intracellular distribution of enzymes of phospholipid metabolism in several gram-negative bacteria. | cell-free extracts of salmonella typhimurium, serratia marcescens, enterobacter aerogenes, and micrococcus cerificans contained the following enzymatic activities related to phospholipid metabolism: cytidine 5'-diphospho-1,2-diacyl-sn-glycerol (cdp-diglyceride):l-serine o-phosphatidyltransferase (phosphatidylserine synthase), phosphatidylserine decarboxylase, cdp-diglyceride:sn-glycero-3-phosphate phosphatidyltransferase (phosphatidylglycerophosphate synthase), phosphatidylglycerophosphate phosp ... | 1977 | 199573 |
| transport of antibiotics and metabolite analogs by systems under cyclic amp control: positive selection of salmonella typhimurium cya and crp mutants. | mutants in the cyclic amp (camp) control system in salmonella typhimurium (cya = adenyl cyclase, crp = camp receptor protein) were partially resistant to growth inhibition by 22 antibiotics (including fosfomycin, nalidixic acid, and streptomycin) and 29 inhibitory analogs of normal bacterial fuel/carbon sources. this resistance was used as the basis for an efficient positive selection of cya and crp mutants. we propose that these antibiotics and analogs enter the bacteria through transport syste ... | 1978 | 201606 |
| role of arylhydroxamic acid acyltransferase in the mutagenicity of n-hydroxy-n-2-fluorenylacetamide in salmonella typhimurium. | | 1978 | 203386 |
| mapping and characterization of the nad genes in salmonella typhimurium lt-2. | an ampicillin enrichment technique was used to isolate 39 nicotinic acid-requiring mutants of salmonella typhimurium lt-2. using interrupted-mating and transductional mapping procedures, three loci, designated nada, nadb, and nadc, were identified. these loci mapped at 33, 82, and 6 min, respectively, on the s. typhimurium linkage map. the arrangement of the loci on the salmonella linkage map corresponded closely to the nada, nadb, and nadc loci on the escherichia coli k-12 linkage map, indicati ... | 1978 | 203571 |
| transcription of the hut operons of salmonella typhimurium. | we have measured, by ribonucleic acid-deoxyribonucleic acid hybrid formation, the amounts of hut-specific ribonucleic acid contained in extracts of various mutant strains of salmonella typhimurium. our data are consistent with a model in which regulation of hut enzyme production occurs at the level of transcription and support earlier genetic evidence indicating that all of the hut genes are transcribed in the clockwise direction on the s. typhimurium chromosome. these results also suggest that ... | 1977 | 192711 |
| resolution and purification of three periplasmic phosphatases of salmonella typhimurium. | a survey of salmonella typhimurium enzymes possessing phosphatase or phosphodiesterase activity was made using several different growth conditions. these studies revealed the presence of three major enzymes, all of which were subsequently purified: a cyclic 2' ,3'-nucleotide phosphodiesterase (ec 3.1.4.d), an acid hexose phosphatase (ec 3.1.3.2), and a nonspecific acid phosphatase (ec 3.1.3.2). a fourth enzyme hydrolyzed bis-(p-nitrophenyl)phosphate but none of the other substrates tested. no ev ... | 1977 | 192712 |
| cyclic amp-dependent synthesis of fimbriae in salmonella typhimurium: effects of cya and pts mutations. | synthesis of bacterial fimbriae (group 1, subtype 1) was shown to be dependent on cyclic amp and was subject to catabolite repression by many carbohydrates. mutations in the genes coding for the energy-coupling protein constituents of the phosphoenolpyruvate:sugar phosphotransferase system prevented repression of fimbrial production by the sugar substrates of this enzyme system. | 1978 | 206537 |
| studies of the stereochemistry and of the role of metal ions in the mechanism of phosphoribosylpyrophosphate synthetase from salmonella typhimurium. | | 1978 | 206555 |
| regulation of two phosphatases and a cyclic phosphodiesterase of salmonella typhimurium. | the regulation of three salmonella typhimurium phosphatases in reponse to different nutritional limitations has been studied. two enzymes, an acid hexose phosphatase (ec 3.1.3.2) and a cyclic phosphodiesterase (ec 3.1.4.d), appear to be regulated by the cyclic adenosine 3' ,5'-monophosphate (amp) catabolite repression system. levels of these enzymes increased in cells grown on poor carbon sources but not in cells grown on poor nitrogen or phosphorus sources. mutants lacking adenyl cyclase did no ... | 1977 | 192713 |
| magnetic resonance studies of the anthranilate synthetase-phosphoribosyltransferase enzyme complex from salmonella typhimurium. | | 1979 | 222217 |
| expression of klebsiella nif and his genes in salmonella typhimurium. | derivatives of salmonella typhimurium carrying f prime or p prime plasmids with klebsiella nif and his genes had specific nitrogenase activities similar to klebsiella in selective conditions, even to showing "hyperinduction" under argon. no evidence was obtained for catabolite repression of normal nif expression but dibutyl cyclic amp often augmented "hyperinduction". in non-selective conditions the klebsiella his nif determinants were rapidly lost from the plasmids; the low levels of nif expres ... | 1977 | 192833 |
| mutagenicity of cancer chemotherapeutic agents in the salmonella/microsome test. | seventeen cancer chemotherapeutic agents were tested for their ability to mutate salmonella typhimurium tester strains in the salmonella/microsome mutagenicity test. there was a high correlation between the mutagenicity and carcinogenicity of a given agent. carcinogens positive in the test were adriamycin, daunomycin, 1-propanol-3,3'-iminodimethanesulfonate, cyclophosphamide, isophosphamide, hycanthone, chlornaphazin, nitrogen mustard, uracil mustard, melphalan, and thio-tepa. two carcinogesn, a ... | 1977 | 193638 |
| genetics and regulation of d-xylose utilization in salmonella typhimurium lt2. | twenty-one xyl- mutants of salmonella typhimurium were selected: all had lost one or more of the activities for d-xylose isomerase, c-xylulokinase, or d-xylose transport. the mutants were classified into five functional groups: xylr, pleiotropic negative (12 mutants); xyla, d-xylose isomerase defective (3 mutants); xylb, d-xylulokinase defective (2 mutants); xylt, d-xylose transport defective (1 mutant); and 3 mutants with defective d-xylose isomerase and d-xylulokinase. some nonsense mutations ... | 1979 | 222732 |
| structural features of salmonella typhimurium lipopolysaccharide required for activation of tissue factor in human mononuclear cells. | activation of mononuclear cell tissue factor was examined utilizing lipopolysaccharides obtained from wild-type and both rc and re mutants of salmonella typhimurium. wild-type (smooth) lipopolysaccharide, galactose-deficient (rc) lipopolysaccharide, heptose-deficient (re) lipopolysaccharide, and lipid a preparations were all active in their ability to generate tissue factor activity in human mononuclear cells grown in tissue culture. polymyxin b has been reported to prevent some of the lethal ef ... | 1977 | 193873 |
| light-induced mutagenicity of neutral red (3-amino-7-dimethylamino-2-methylphenazine hydrochloride). | illumination of salmonella typhimurium in the presence of neutral red (3-amino-7-dimethylamino-2-methylphenazine hydrochloride) results in mutations of the base substitution type. | 1977 | 191177 |
| asbestos and glass fibres in bacterial mutation tests. | asbestos fibres are carcinogenic in man and experimental animals but fine glass fibres are known, at present, only to be carcinogenic in experimental animals. asbestos and glass fibres have been studied in mutation tests using auxotrophic strains of escherichia coli and salmonella typhimurium. the mutagenic activities of the positive control mutagens ultraviolet light, potassium chromate, ethyl methanesulphonate and benzo(a)pyrene were detected in the experiments. however, no mutagenic activity ... | 1977 | 194149 |
| immunochemical analysis of membrane vesicles from escherichia coli. | membrane vesicles isolated from escherichia coli ml 308--225 have been analyzed by crossed immunoelectrophoresis, and immunoprecipitates corresponding to the following cellular components have been identified: atpase (ec 3.6.1,3), two or three nadh dehydrogenases (ec 1.6.99.3), d-lactate dehydrogenase (ec 1.1.1.27), glutamate dehydrogenase (ec 1.4.1.4), dihydro-orotate dehydrogenase (ec 1.3.3.1), 6-phosphogluconate dehydrogenase (ec 1.1.1.43), polynucleotide phosphorylase (ec 2.3.7.8), beta-gala ... | 1979 | 218620 |
| the metabolism of d-arabinose by salmonella typhimurium. | | 1977 | 200704 |
| synthesis of adenosine 3':5'-cyclic monophosphate in salmonella typhimurium growing in continuous culture. | | 1979 | 219134 |
| effects of cyclic amp altering drugs on endotoxin-induced termination of pregnancy. | the effects of dibutyryl-cyclic amp (dbcamp), propranolol, and theophylline on endotoxin (lps) challenged pregnant mice was determined by comparing the patterns of termination and times of fetal expulsion. endotoxin isolated from wild type (wt) and re chemotype mutant cells of salmonella typhimurium was used. wild type lps caused the expulsion of the fetuses, while re lps primarily caused the resorption of the fetuses. the major change in pattern occurred in the propranolol treated re lps challe ... | 1979 | 219454 |
| effect of endotoxin on uterine cycle amp in pregnant mice. | the effect of endotoxin (lps) on uterine camp was determined by measuring the levels of camp and camp phosphodiesterase after challenge. two lps preparations, isolated from wild type (wt) and re chemotype mutant cells of salmonella typhimurium were used. the pattern of termination differed with wt lps resulting in expulsion of the fetuses, and re lps primarily causing the resorption of the fetuses. the animals challenged with wt lps showed a decrease in uterine camp when the mice were starting t ... | 1978 | 205927 |
| alkyl methane sulfonate mutation of diploid human lymphoblasts and salmonella typhimurium. | concentration dependence of mutation in equigenerational exposures to methyl, ethyl, propyl, and butyl methanesulfonates has been determined in diploid human lymphoblasts and salmonella typhimurium. forward mutation was measured at the hypoxanthine guanine phosphoribosyltransferase locus in human lymphoblasts and at the putative guanine phosphoribosyltransferase locus in s. typhimurium. reverse mutation at the his g46 locus was also measured in s. typhimurium. this analysis and previous reports ... | 1978 | 206353 |
| survival of bacteria in carcasses. | bacteria injected into the bloodstream of guinea pigs shortly before death decreased in number in carcass tissues for about 1 h after death. if initial bacterial numbers were sufficiently low, all bacteria were eliminated, and carcass tissues were sterile 24 h after death. carcass tissue sterility was maintained with an initial density of clostridium perfringens or salmonella typhimurium of 20 cells per g or with an initial density of the other species examined of several hundred cells per gram. ... | 1979 | 222211 |
| kinetic and magnetic resonance studies of the interaction of the cr-atp complex with phosphoribosylpyrophosphate synthetase from salmonella typhimurium. | | 1979 | 222212 |
| pyridine nucleotide cycle of salmonella typhimurium: regulation of nicotinic acid phosphoribosyltransferase and nicotinamide deamidase. | nicotinic acid phosphoribosyl transferase (naprtase) and nicotinamide deamidase activities from salmonella typhimurium were examined regarding their regulation by either feedback inhibition or repression mechanisms. the results indicate that neither enzyme is subject to feedback inhbition. nicotinamide deamidase does not appear to be under repression control. naprtase, however, is repressed when cells are grown in minimal medium supplemented with various intermediates of the pyridine nucleotide ... | 1979 | 222729 |
| uptake and catabolism of d-xylose in salmonella typhimurium lt2. | salmonella typhimurium lt2 grows on d-xylose as sole carbon source with a generation time of 105 to 110 min. the following activities are induced at the indicated time after the addition of the inducer, d-xylose: d-xylulokinase (5 min), d-xylose isomerase (7 to 8 min), and d-xylose transport (10 min). all other pentoses and pentitols tested failed to induce isomerase or kinase. synthesis of d-xylose isomerase was subject to catabolite repression, which was reversed by the addition of cyclic aden ... | 1979 | 222731 |
| arginine auxotrophic phenotype of mutation in pyra of salmonella typhimurium: role of n-acetylornithine in the maturation of mutant carbamylphosphate synthetase. | mutations in pyra that abolish catalytic activity of carbamylphosphate synthetase cause auxotrophy for both arginine and a pyrimidine. eight pyra mutants auxotrophic only for arginine (aux) were isolated by the mutagenized phage technique; three of these required arginine only at low temperature (20 degrees c). explanations of the aux phenotype based on bradytrophy were eliminated by the discovery that blocking the utilization of carbamylphosphate for pyrimidine biosynthesis by insertion of an a ... | 1978 | 207669 |
| arylsulfatase in salmonella typhimurium: detection and influence of carbon source and tyramine on its synthesis. | arylsulfatase synthesis was shown to occur in salmonella typhimurium lt2. the enzyme had a molecular weight of approximately 50,000 and was separated into five forms by isoelectrofocusing. the optimal ph for substrate hydrolysis was ph 6.7, with michaelis constants for nitrocatechol sulfate and nitrophenyl sulfate being 4.1 and 7.9 mm, respectively. enzyme synthesis was strongly influenced by the presence of tyramine in the growth medium. the uptake of [14c]tyramine and arylsulfatase synthesis w ... | 1979 | 222733 |
| effect of substitution of monovalent anions in external medium on the swimming pattern of salmonella typhimurium. | the effect of replacement of ions in the extracellular medium on the swimming pattern of bacteria (salmonella typhimurium) has been investigated. the replacement of chloride ion (cl-) in the standard medium by methanesulfonate ion (ms-) or by propionate ion (pr-) induced an increase in the tumbling frequency, or a decrease of the end-to-end distances of tracks. replacement of ms- by cl- resulted in transient depression of tumbling, and replacement of pr- by cl- resulted in immediate recovery of ... | 1978 | 207676 |
| alteration of the ability of liver microsomes to activate n-2-fluorenylacetamide to a mutagen of salmonella typhimurium during hepatocarcinogenesis. | | 1978 | 208764 |
| [seromonitoring of laboratory mouse and rat colonies for common murine pathogens (author's transl)]. | during a period from 1973 to 1978, 392 and 225 lots including 12,232 mouse and 8,044 rat individual sera, respectively, were examined for antibodies to murine hepatitis virus, sendai virus, bordetella bronchiseptica, mycoplasma pulmonis, tyzzer agents, salmonella typhimurium and corynebacterium kutscheri. of mouse lots 94.5% and 39.3% from breeder and user colonies, respectively, were negative for all antibodies examined as well as 31.6% and 17.2% of rat breeder and user colonies, respectively. ... | 1979 | 225183 |
| utilization of d-xylose by wild-type strains of salmonella typhimurium. | enzyme studies of strains of salmonella typhimurium representing biotypes that utilized d-xylose rapidly (xylose strong) or slowly (xylose weak) showed that they were different in the utilization of d-xylose because the xylose-weak strains were deficient in the transport of d-xylose. this observation is consistent with the idea that strains of the different xylose-weak biotypes, e.g. biotypes 17 to 32, were descended from strains of xylose-strong types, particularly from biotype 1. | 1979 | 216662 |
| 5-fluoroorotate-resistant mutants of salmonella typhimurium. | spontaneously occurring mutants of salmonella typhimurium resistant to 5-fluoroorotate (5-foa) were isolated. one class of mutant showed marked derepression of pyrimidine biosynthetic enzymes and had the unusual property of being unable to grow on nutrient agar. however, when the osmotic strength of nutrient agar was increased, the mutants were able to grow. the genetic basis for the osmotic fragility and elevated pyr enzyme synthesis was the result of mutations affecting pyrh, encoding the enzy ... | 1978 | 217514 |
| inhibitors for the mutagenicities of colon carcinogens, 1,2-dimethylhydrazine and azoxymethane, in the host-mediated assay. | inhibitory effects of several chemicals on the mutagenicities of 1,2-dimethylhydrazine (dmh) and azoxymethane (aom) for salmonella typhimurium g46 in the host-mediated assay were investigated. they were carbon disulfide (cs2), tetraethylthiuram disulfide (disulfiram, dsf), sodium diethyldithiocarbamate (sddc), ethylene-bis(dithiocarbamato) manganese (maneb), pyrazole (pz), aminoacetonitrile hydrogen sulfate (aan), and sodium selenite (se). all the compounds, except for se, inhibited the mutageni ... | 1979 | 228849 |
| mutagenicity of chamuvaritin: a benzyldihydrochalcone isolated from a medicinal plant. | the mutagenic effects of chamuvaritin, dihydrobenzylchalcone isolated from uvaria chamae, were investigated using salmonella typhimurium tester strains ta92, ta94--98, ta100--1535, ta1537 and ta1538. the phytochemical was mutagenic in tester strains ta98 and ta100 and required activation by the hepatic s-9 microsomal enzyme preparation. | 1979 | 228850 |
| pyridine nucleotide cycle of salmonella typhimurium: isolation and characterization of pnca, pncb, and pncc mutants and utilization of exogenous nicotinamide adenine dinucleotide. | mutants of salmonella typhimurium lt-2 deficient in nicotinamidase activity (pnca) or nicotinic acid phosphoribosyltransferase activity (pncb) were isolated as resistant to analogs of nicotinic acid and nicotinamide. information obtained from interrupted mating experiments placed the pnca gene at 27 units and the pncb gene at 25 units on the s. typhimurium lt-2 linkage map. a major difference in the location of the pnca gene was found between the s. typhimurium and escherichia coli linkage maps. ... | 1979 | 220211 |
| bacterial lipopolysaccharide depresses spontaneous, evoked, and ionophore-induced transmitter release at the neuromuscular junction. | the neurotoxocity of rna-free lipopolysaccharide (lps) extracted from salmonella typhimurium (sr-11) was tested at the frog neuromuscular junction using intracellular recording techniques. spontaneous miniature endplate potential (mepp) frequency was reduced to 45% of control after 60 minutes in the presence of 10 and 50 micrograms lps/ml ringer's solution. elevation of extracellular [ca] to 10 mm converted the mepp frequency response to a biphasic pattern of early acceleration followed by late ... | 1979 | 229236 |
| phagolysosome formation, cyclic adenosine 3':5'-monophosphate and the fate of salmonella typhimurium within mouse peritoneal macrophages. | salmonella typhimurium did not inhibit fusion of lysosomes with the phagocytic vacuoles in infected macrophages and caused no increase in cyclic adenosine 3':5'-monophosphate. glutaraldehyde-killed bacteria showed rapid ultrastructural degeneration within the phagolysosomes. in contrast, untreated bacteria were resistant to digestion by lysosomal enzymes. intracellular survival of this species appears to depend on resistance to, and not evasion of, lysosomal enzymes. | 1979 | 220378 |
| migration of epithelial cells in the small intestine of mice perorally infected with coxsackievirus b5. | the rate of cell migration in the small intestine during enteric viral infections has not been assessed previously. cd-1 mice (33 days old) were infected perorally with 1.0 x 10(8) plague-forming units of coxsackievirus b5 and 12 hr later were injected intraperitoneally with 2 micron ci of [3h]thymidine/g of body weight. after 2, 12, 24, 48, 60, and 72 hr, mice were killed, and the small intestine was removed. specimens obtained at each interval were examined by radioautography; similar specimen ... | 1979 | 221595 |
| altered linkage values in phage p22--mediated transduction caused by distant deletions or insertions in donor chromosomes. | the effects of distant deletions or insertions in the salmonella typhimurium donor strains on p22--mediated cotransducibility of genetic markers was studied. we found that deletions of histidine operon, unit 44 of the chromosome map, changed the linkage of markers purf and aroc (unit 49) and pyrf and trpa (unit 34). they did not change the linkage of more distant markers pyre and cyse. the effect of three types of insertions was examined. the donor strains carried f factor, tn10 transposon or pi ... | 1979 | 232232 |
| phosphoribosylpyrophosphate (prpp) synthetase mutant in salmonella typhimurium. | | 1979 | 232626 |
| isolation of super-repressor mutants in the histidine utilization system of salmonella typhimurium. | two super-repressor mutations in the histidine utilization (hut) operons of salmonella typhimurium are described. cells bearing either of these mutations have levels of hut enzymes that do not increase above the uninduced levels when growth is in the presence of either histidine or the gratuitous inducer imidazole propionate. both mutations lie in the region of the gene for the hut repressor, hutc, and reverse mutations of both are to the constitutive (repressor-negative) rather than to the indu ... | 1975 | 234417 |
| deoxycytidine triphosphate deaminase of salmonella typhimurium. purification and characterization. | deoxycytidine triphosphate deaminase (ec 3.5.4., dctp aminohydrolase) of salmonella typhimurium lt2 has been pruified 500-fold. the reaction requires the presence of mg-2plus, mn-2plus, ca-2lus, or co-2plus. kinetics of the reaction with varying mg-2plus concentrations, keeping the concentration of dctp constant, suggests that the true substrate of the reaction is mgdctp. the dependence of the rate of reaction on dctp concentration in the presnece of 5-fold excess of mg-2plus is sigmoid, with a ... | 1975 | 234434 |
| differential fluorescence labelling with 5-dimethyl-aminonaphthalene-1-sulfonyl chloride of intact cells and isolated membranes in salmonella typhimurium and acholeplasma laidlawii. | for fluorescence labelling intact cells and isolated cell envelopes (membranes) from salmonella typhimurium and acholeplasma laidlawii were treated with mixed dansylchloride-lecithin-cholesterol vesicles. this kind of dansylation, which has been supposed to be specific for cell surface proteins, produced fluorescent protein pattern after sds-polyacrylamide gel electrophoresis only when isolated envelopes were dansylated. acid hydrolysis of fluorescent cell envelopes of salmonella typhimurium yie ... | 1975 | 235245 |
| phosphoribosylpyrophosphate synthetase (ribose-5-phosphate pyrophosphokinase) from salmonella typhimurium. | | 1978 | 211378 |
| decreased binding of polymyxin by polymyxin-resistant mutants of salmonella typhimurium. | polymyxin-resistant pmra strains were shown to absorb only about 25% of the amount of polymyxin absorbed by the corresponding polymyxin-sensitive parent strains. the lipopolysaccharide from the pmra strains bound less polymyxin than the lipopolysaccharide from the parent strains. | 1979 | 222738 |
| nucleoside diphosphokinase from salmonella typhimurium. | | 1978 | 211385 |
| [inner membrane structures and the electron paramagnetic resonance spectra of salmonella typhimurium cells after their interaction with nitroso compounds]. | | 1978 | 214672 |
| depression of spontaneous and ionophore-induced neurotransmitter release by salmonella. | exposure of frog neuromuscular junctions to heat-killed, lyophilized salmonella typhimurium (sr 11) produces an early increase in spontaneous transmitter release followed by depression of release and blockade of the obligatory release usually induced by ionophore x537a. | 1979 | 223876 |
| regulation of catalase synthesis in salmonella typhimurium. | the specific activity of catalase in salmonella typhimurium and other enteric bacteria decreased during the logarithmic phase of growth and increased at the onset and during the stationary phase. the increase in catalase synthesis at the end of the exponential phase in s. typhimurium cells coincided with the lowest ph value reached by the culture. maintenance of the ph at a constant neutral value did not alter the typical pattern of synthesis in contradiction of the results previously reported ( ... | 1975 | 238955 |
| the effects of additional flora on the response of salmonella mutants lodged in the gastrointestinal tract. | a histidine auxotroph of salmonella typhimurium, strain ta1538, will lodge for several months in the gastrointestinal tract of otherwise germ-free rats and of rats additionally associated with bacteria characteristic of the normal flora such as lactobacillus plantarum and bacteroides vulgatus. in the presence of the additional flora, the concentration of strain ta1538 is diminished in the stomach but not in the lower gastrointestinal tract or in the feces. following the ingestion of 2-nitrofluor ... | 1977 | 318921 |
| effect of silica on the innate resistance of inbred mice to salmonella typhimurium infection. | the role of macrophages in the innate immunity of (cba/n female x dba/2n male)f1 female mice to salmonella typhimurium was assessed with silica, an agent which has been reported to selectively inactivate macrophages. silica, administered intravenously to mice, markedly decreased the phagocytic capacity of splenic macrophages but had no effect on splenic responsiveness to the b-cell mitogen lipopolysaccharidide or the t-cell mitogen phytohemagglutinin, nor did it affect the frequency of surface i ... | 1979 | 226477 |
| phylogenetic relationships between different d-xylose biogroups in wild-type salmonella typhimurium strains and a suggested evolutionary pathway. | | 1979 | 227827 |
| a transport system for phosphoenolpyruvate, 2-phosphoglycerate, and 3-phosphoglycerate in salmonella typhimurium. | salmonella typhimurium strain lt-2 was found to utilize phosphoenolpyruvate, 2-phosphoglycerate, and 3-phosphoglycerate as sole sources of carbon and energy for growth, but escherichia coli strains did not. the following evidence suggests that this growth difference was due to the presence in salmonella cells of an inducible phosphoglycerate permease distinct from previously studied transport systems: (a) the ability of cells to take up 3-phospho[14-c]glycerate was induced by growth in the prese ... | 1975 | 238977 |
| regulation of the ammonia assimilatory enzymes in salmonella typhimurium. | the regulation of glutamate dehydrogenase (ec 1.4.1.4), glutamine synthetase (ec 6.3.1.2), and glutamate synthase (ec 2.6.1.53) was examined for cultures of salmonella typhimurium grown with various nitrogen and amino acid sources. in contrast to the regulatory pattern observed in klebsiella aerogenes, the glutamate dehydrogenase levels of s. typhimurium do not decrease when glutamine synthetase is derepressed during growth with limiting ammonia. thus, it appears that the s. typhimurium glutamin ... | 1975 | 240804 |
| [study of the mutagenic activity of mazheptil]. | mutagenic activity of the psychotropid drug--majeptil was studied. majeptil does not induce gene mutations on salmonella typhimurium and chromosomal aberrations in mice bone marrow cells in vivo. it is shown that majeptil increase the level of chromosome aberrations in the culture of human peripheral blood lymphocytes. it is also active in the dominant lethal test on mice. | 1975 | 241146 |
| isolation of temperature-sensitive pantothenate kinase mutants of salmonella typhimurium and mapping of the coaa gene. | temperature-sensitive pantothenate kinase mutants of salmonella typhimurium lt2 were selected by using the excretion of pantothenate at the nonpermissive temperature as a screening method. thermolability of the pathothenate kinase activity in extracts of the mutants was demonstrated. the mutations were mapped at min 89 of the salmonella chromosome, near rpob, by transduction. as pantothenate kinase catalyzes the first step in the biosynthesis of coenzyme a from pantothenate, the new genetic locu ... | 1979 | 230178 |
| mechanism for induction of anti-dna antibodies by bacterial lipopolysaccharides in mice; ii. correlation between anti-dna induction and polyclonal antibody formation by various polyclonal b lymphocyte activators. | the capacity of various polyclonal b lymphocyte activators (pba) to induce, in mice, the formation of anti-dna antibodies was compared with their ability to mediate the release of dna in circulating blood and to stimulate polyclonal antibody synthesis in vivo. anti-dna antibodies or polyclonal antibody synthesis were induced in mice after the injection of at least 10 microgram lipopolysaccaride (lps) from salmonella typhimurium, 1 mg dextran sulfate (ds), or 2 mg purified protein derivative of t ... | 1977 | 303258 |
| microsomal activation to mutagens of antischistosomal methyl thioxanthenones and initial tests on a possibly non-mutagenic analogue. | five methylthioxanthenone and methylbenzothiopyranoindazole analogues, including lucanthone (miracil d), are non-mutagenic for salmonella typhimurium but are activated to mutagens by a rat liver microsome preparation. hydroxymethyl analogues, including hycathone (etrenol), are mutagenic in the absence of microsomes. it seems reasonable to assume that the hydroxymethyl derivatives are the more proximal mutagens and that salmonella is unable to carry out the hydroxylation necessary for mutagen act ... | 1975 | 235087 |
| purine nucleoside phosphorylase from escherichia coli and salmonella typhimurium. purification and some properties. | the purine nucleoside phosphorylases from escherichia coli and from salmonella typhimurium have been purified to electrophoretic homogeneity and crystallized. comparative studies revealed that the two enzymes are very much alike. they obey simple michaelis-menten kinetics for their substrates with the exception of phosphate for which they show negative cooperativity. gel filtration on sephadex g-200 of the native enzymes revealed a molecular weight for both enzymes of 138000 plus or minus 10%. b ... | 1975 | 235429 |
| factors affecting mutagenic activity of cigarette smoke condensate in salmonella typhimurium ta 1538. | smoke condensates from burley tobacco, bright-type tobacco and various brands of commercial cigarettes were tested for mutagenicity by using a microsomal test system with salmonella typhimurium ta 1538. smoke condensate from burley tobacco had much higher mutagenic activity than that from bright-type tobacco. increased mutagenic activity was observed with smoke condensates from burley tobacco grown with increasing amounts of nitrogen fertilizer, and from commercial cigarettes blended with burley ... | 1977 | 319352 |
| mitomycin c-induced expression of trpa of salmonella typhimurium inserted into the plasmid cole1. | ecori endonuclease digestion of the deoxyribonucleic acid of a phi80 transducing phage carrying the entire tryptophan (trp) operon of salmonella typhimurium (phi80 s.t.trpe-a) yielded a 4.3 x 10(6)-dalton fragment containing intact trpe, trpd, and trpc and a 3.35 x 10(6)-dalton fragment containing intact trpa. the trpa fragment inserted into ecori-cleaved plasmids cole1 and cr1 was expressed regardless of its orientation of insertion. mitomycin c, a compound that induces colicin e1 production in ... | 1977 | 318646 |
| mutations affecting glutamine synthetase activity in salmonella typhimurium. | a positive selection procedure has been devised for isolating mutant strains of salmonella typhimurium with altered glutamine synthetase activity. mutants are derived from a histidine auxotroph by selecting for ability to grow on d-histidine as the sole histidine source. we hypothesize that the phenotype may be based on a regulatory increase in the activities of the d-histidine racemizing enzymes, but this has not been established. spontaneous glutamine-requiring mutants isolated by the above se ... | 1975 | 238935 |
| gene order of the histidine utilization (hut) operons in klebsiella aerogenes. | p1-sensitive mutants of klebsiella aerogenes were isolated and the gene order of the hut region was then determined using p1-mediated transduction. the genes are located in the klebsiella chromosome between gal and bio as in salmonella typhimurium. the gene order, gal, huti, hutg, hutc, huu, huth, bio is also the same as that observed in s. typhimurium. | 1975 | 238937 |
| the contribution of metronidazole and two metabolites to the mutagenic activity detected in urine of treated humans and mice. | the urine of two patients receiving therapeutic doses of the trichomonacide, metronidazole, was analyzed for mutagenic activity using the histidine auxotroph ta1535 of salmonella typhimurium. the activity detected in the urine was significantly higher than could be accounted for by the presence of the administered drug. chromatographic analysis of the urine indicated the presence of the metabolite 1-(2-hydroxyethyl)-2-hydroxymethyl-5-nitroimidazole, which when tested in vitro with ta1535 was fou ... | 1977 | 318924 |
| formate hydrogenlyase system in salmonella typhimurium lt2. | isolation from salmonella typhimurium of mutants unable to reduce benzyl viologen under anaerobic conditions has allowed the study of the factors involved in the multienzymic formate hydrogenylase system. 1. depending on the affected activities, different classes of mutants were found: fhl-a mutants have lost formate dehydrogenase 1 and formate dehydrogenase 2 activities; mutations in fdha (117 min) or fdhb (33 min) lead to such a phenotype. fhl-b and fhl-c mutants have lost formate dehydrogenas ... | 1977 | 318997 |
| mitogenic stimulation of murine spleen cells: relation to susceptibility to salmonella infection. | the screening of several inbred strains of mice suggested that the capacity of their spleen cells to respond to the mitogenic effect of lipopolysaccharide (lps) of gram-negative bacteria was correlated with their resistance to intraperitoneal infection with salmonella typhimurium. an infection of lps into mice caused changes in the in vitro responsiveness of their spleen cells to the mitogenic effects of lps and phytohemagglutinin. pretreatment of mice with whole ultraviolet (uv)-killed bacteria ... | 1977 | 319060 |
| soluble and membrane-bound aspartate-binding activities in salmonella typhimurium. | the specificities of the soluble and membrane aspartate-binding activities were compared with each other and with the specificity of aspartate chemotaxis and were found to be distinct. the soluble aspartate-binding protein was purified to homogeneity and had a molecular weight of 30,000. the dissociation constant was 10(-6) m for aspartate, and the protein bound glutamate, cysteic acid, and 2-amino-3-phosphonopropionate. aspartate transport was inhibited by cysteic acid. | 1975 | 239919 |
| mutagenicity of five cyclic n-nitrosamines: assay with salmonella typhimurium. | the mutagenicity of five cyclic n-nitrosamines was studied with the use of salmonella typhimurium ta1535 in vitro with and without microsomal activation. the carcinogens nitrosopiperidine and nitrosopyrrolidine required metabolic activation before manifesting mutagenic activity. nitrosoproline and nitrosohydroxyproline, noncarcinogens, were not mutagenic. nitroso-3-pyrrolidinol was mutagenic in the absence of microsomes, thereby suggesting a role of hydroxylation in the metabolic activation of n ... | 1977 | 319245 |
| airborne mutagens bioassayed in salmonella typhimurium. | particulate airborne pollutants, collected in buffalo, new york, and berkeley, california, were asayed for mutagenic activity in the ames salmonella typhimurium test system. mutagens requiring liver enzymes for activation, as well as direct acting mutagens, were readily detected in the buffalo sample. by contrast, only direct acting mutagens were detected in the berkeley sample. | 1977 | 319246 |
| transposition of plasmid dna segments specifying hydrocarbon degradation and their expression in various microorganisms. | the conjugative tol plasmid (75 mdal), specifying biodegradation of xylenes, toluene, and trimethylbenzene derivatives, undergoes dissociation in pseudomonas aeruginosa pao to a nonconjugative tol(*) plasmid (28 mdal) and a transfer plasmid termed toldelta (48 mdal). the tol(*) plasmid is rendered transmissible through introduction of a number of conjugative plasmids such as factor k, cam, and toldelta but not by the fp2 derivative pr0271. transfer of tol(*) via factor k or toldelta is mediated ... | 1978 | 277912 |
| carcinogenicity test of six nitrosamides and a nitrosocyanamide administered orally to rats. | six nitrosamides [ethylnitrosourea (enu), 2-hydroxyethylnitrosourea (henu), carboxymethylnitrosourea, 1-nitroso-5,6-dihydrouracil (ndhu), 1-nitrosohydantoin, and n-methyl-n-nitrosobenzamide (mnb)] and ethylnitrosocyanamide (enc) were administered chronically in sodium citrate-buffered drinking water to mrc wistar rats. enu induced tumors of the reticuloendothelial system (res) (50% incidence), mammary glands, and large intestine. ndhu in drinking water produced hepatocellular carcinomas (96% inc ... | 1979 | 286123 |
| patterns of transcription in bacteriophage p22-infected salmonella typhimurium. | two peaks of rna synthesis (early and late) are directed by bacteriophage p22 in lytic infections of salmonella typhimurium. late rna synthesis is not seen in p22 23- infections; neither early nor late rna synthesis occurs in p22 24- infections. genes 23 and 24 of p22 appear to be analogous to genes q and n of lambda, respectively. | 1977 | 319258 |
| inhibition of promutagen activation by the antioxidants butylated hydroxyanisole and butylated hydroxytoluene. | butylated hydroxyanisole (bha) and butylated hydroxytoluene (bht) exhibited antimutagenic activity in the salmonella typhimurium reversion test. both bha and bht reduced reversion induced by chemicals requiring metabolic activation for effectiveness. however, they did not affect reversion induced by direct-acting mutagens. these results suggested that bha and bht may inhibit the metabolic activation processes and demonstrated that the s. typhimurium reversion test may be used to identify inhibit ... | 1979 | 287836 |
| pyrolysis products from amino acids and protein: highest mutagenicity requires cytochrome p1-450. | pyrolysis products of proteins and amino acids are highly mutagenic, but metabolism of these chemicals by rat liver subcellular fractions is known to be required for production of the mutagenic intermediates. we examined the mutagenesis of seven purified pyrolysis products from tryptophan, lysine, glutamic acid, and soybean globulin with salmonella typhimurium strain ta98 in the presence of liver fractions from genetically "responsive" c57bl/6n and ah(b)/ah(d) or "nonresponsive" dba/2n and ah(d) ... | 1979 | 293693 |
| in vitro metabolic activation of ethidium bromide and other phenanthridinium compounds: mutagenic activity in salmonella typhimurium. | | 1977 | 319349 |
| nitrous acid mutagenesis of duplex dna as a three-component system. | purified native hemophilus influenzae dna is relatively insusceptible to nitrous acid (na) mutagenesis in vitro, but is readily mutated following denaturation. na mutagenicity for duplex dna is significantly increased in the presence of various alcohols, glycols, phenols or primary amines. phenol-extracted dna contains dissociable contaminants of low molecular weight that enhance na mutagenesis. enhancement of na mutagenesis by phenol and by spermine is due to the formation of unstable molecular ... | 1979 | 314585 |
| studies on mutagenicity of irradiated sugar solutions in salmonella typhimurium. | irradiated sugar solutions are mutagenic towards salmonella typhimurium, the effect being dose-dependent up to 2.0 mrad. at all doses, ribose solution exhibited greater mutagenicity than did sucrose solution. the mutagenic effect was observed only in dividing cells and appears to be directly related to the growth rate. a larger proportion of revertants was observed after incubation with irradiated sugar solution for a period of 4 h than for 24 h. irradiation of the sugar solutions in the frozen ... | 1977 | 319351 |
| chemical composition and biological activities of a phenol-water extract from haemophilus influenzae type a. | ribonucleic acid was removed from a phenol-water extract of haemophilus influenzae type a by streptomycin sulfate. this preparation was called purified preparation or pp. it contained neutral sugars (glucose, galactose, mannose, pentose), glucosamine, amino acids, and fatty acids. heptose and 2-keto-3-deoxyoctonic acid were not present. the biological properties and immunogenicity were compared with the activities of lipopolysaccharide of escherichia coli or salmonella typhimurium. higher doses ... | 1979 | 317593 |
| deoxyribose-5-phosphate aldolase from salmonella typhimurium. | | 1975 | 237187 |
| thymidine-requiring mutants of salmonella typhimurium that are defective in deoxyuridine 5'-phosphate synthesis. | in a salmonella typhimurium strain made diploid for the thy region by introduction of the escherichia coli episome, f'15, mutants resistant to trimethoprim in the presence of thymidine were selected. one was shown to be defective in deoxyuridine 5'-phosphate (dump) synthesis; it requires deoxyuridine or thymidine for growth and is sensitive to trimethoprim in the presence of deoxyuridine. genetic studies showed that the mutant is mutated in two genes, dcd and dum, located at 70 and 18 min, respe ... | 1977 | 318643 |
| tris(2,3-dibromopropyl) phosphate: mutagenicity of a widely used flame retardant. | tris(2,3-dibromopropyl) phosphate, a widely used flame-retardant additive for textiles, is mutagenic to histidine-requiring strains of salmonella typhimurium. extracts of fabrics treated with this compound are also capable of inducing mutations in these bacterial strains. | 1977 | 318761 |
| antimicrobial susceptibility of salmonella isolates from the broiler chicken industry in ontario. | antibacterial drug resistance among 219 salmonella isolates recovered during 1974 from poultry and poultry environments at the various production stages of broiler chickens in three integrated ontario companies are recorded. all isolates were susceptible to ampicillin, trimethroprim-sulfamethoxazole complex, furazolidone, cephaloridine and amoxicillin. a relative increase in resistance to tetracycline and streptomycin with an accompanying decrease in resistance to triple sulfa compound was recor ... | 1977 | 318909 |
| mutagenicity of n-butyl-n-(4-hydroxybutyl)nitrosamine, a bladder carcinogen, and related compounds. | n-butyl-n-(4-hydroxybutyl)nitrosamine (bbn), which specifically induces bladder tumors, was shown to be mutagenic to salmonella typhimurium strains ta 1535 and ta100 in the presence of an s-9 mix prepared from the liver of rats treated with polychlorinated biphenyl. reduced nicotinamide adenine dinucleotide was a more effective cofactor than reduced nicotinamide adenine dinucleotide phosphate in the activation of bbn by the rat liver s-9 fraction, n-butyl-n-(3-carboxypropyl)nitrosamine, reported ... | 1977 | 318920 |
| properties of the galactose binding protein of salmonella typhimurium and escherichia coli. | the galactose binding protein implicated in transport and in chemotaxis has been purified to homogeneity from the shock fluids of salmonella typhimurium and escherichia coli. both proteins are monomers of molecular weight 33 000 and exhibit cross-reactivity with antibody. the salmonella galactose receptor showed binding of 1 mol of [14c]galactose or 1 mol of [14c]glucose at saturation. the dissociation constants were 0.38 and 0.17 mum, respectively. in light of the previously published report th ... | 1977 | 319823 |
| outer membrane of salmonella typhimurium. identification of proteins exposed on cell surface. | proteins exposed on the outer surface of the outer membrane of salmonella typhimurium were identified by reacting intact cells with a covalent labeling reagent. since the outer membrane permitted the free diffusion of small hydrophilic molecules, we used a macromolecular reagent, cnbr-activated dextran, as the non-penetrating labeling agent. we also used a mutant producing a lipopolysaccharide with a very short (i.e. hexasaccharide) carbohydrate chain, in order to avoid steric hindrance by the c ... | 1977 | 319828 |
| repression and inhibition of transport systems for branched-chain amino acids in salmonella typhimurium. | kinetics of the transport systems common for entry of l-isoleucine, l-leucine, and l-valine in salmonella typhimurium lt2 have been analyzed as a function of substrateconcentration in the range of 0.5 to 45 mum. the systems of transport mutants, ka203 (ilvt3) and ka204 (ilvt4), are composed of two components; apparent km values for uptake of isoleucine, leucine, and valine by the low km component are 2 mum, 2 to 3 mum, and 1 mum, respectively, and by the high km component 30 mum, 20 to 40 mum, a ... | 1977 | 320186 |
| comparative electrophilicity, mutagenicity, dna repair induction activity, and carcinogenicity of some n- and o-acyl derivatives of n-hydroxy-2-aminoflourene. | n-myristoyloxy-n-acetyl-2-aminofluorene, n-acetoxy-n-myristoyl-2-aminofluorene, n-myristoyloxy-n-myristoyl-2-aminofluorene, and n-hydroxy-n-myristoyl-2-aminofluorene each yielded a high incidence of sarcomas in male rats within 5 to 7 months after s.c. injection of 64 micronmoles in divided doses. n-acetoxy-n-acetyl-2-aminofluorene and n-hydroxy-2-acetylaminofluorene, although potent carcinogens at the s.c. site, were less active than the above derivatives with a myristoyl substituent. n-sulfono ... | 1977 | 322856 |
| influence of methionine biosynthesis on serine transhydroxymethylase regulation in salmonella typhimurium lt2. | the enzyme serine transhydroxymethylase (ec 2.1.2.1; l-serine:tetrahydrofolate-5,10-hydroxymethyltransferase) is responsible both for the synthesis of glycine from serine and production of the 5,10-methylenetetrahydrofolate necessary as a methyl donor for methionine synthesis. two mutants selected for alteration in serine transhydroxymethylase regulation also have phenotypes characteristic of metk (methionine regulatory) mutants, including ethionine, norleucine, and alpha-methylmethionine resist ... | 1977 | 320194 |
| isolation and characterization of catalase deficient mutants of salmonella typhimurium. | catalase deficient mutants (kat) of salmonella typhimurium have been isolated. the mutantions kata1, katc6 and katd9 appear to map at about minute 10 on the salmonella chromosome. the katc6 and katd9 lesions are complemented by the e. coli f'128 (lac + pro +) episome but the kata1 lesion is not. katb2 maps at about minute 100. none of the mutants are oxygen sensitive; they grow as well as wild bacteria, even when aerated. | 1977 | 320456 |
| mutagenic activities in vitro and in vivo of five antischistosomal compounds. | five antischistosomal compounds--hycanthone, two of its chloroindazole analogs (ia-4 and ia-4 n-oxide), oxamniquine, and metrifonate--were tested for mutagenic activity, using salmonella typhimurium strains ta 98 and ta 100 under in vitro and in vivo (host-mediated) conditions. in all assay systems hycanthone exhibited by far the highest mutagenic potency. although oxamniquine and metrifonate had low metagenic activity in vitro and although their administration resulted in urine of low metagenic ... | 1977 | 319220 |
| 9-aminoacridine-a frameshift mutagen for salmonella typhimurium ta 1537 inactive at the hgprt locus in human lymphoblasts. | | 1977 | 320466 |