Publications
| Title | Abstract | Year Filter | PMID(sorted descending) Filter |
|---|
| 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 |
| phosphoribosylpyrophosphate (prpp) synthetase mutant in salmonella typhimurium. | 1979 | 232626 | |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| phylogenetic relationships between different d-xylose biogroups in wild-type salmonella typhimurium strains and a suggested evolutionary pathway. | 1979 | 227827 | |
| 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 |
| [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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| magnetic resonance studies of the anthranilate synthetase-phosphoribosyltransferase enzyme complex from salmonella typhimurium. | 1979 | 222217 | |
| kinetic and magnetic resonance studies of the interaction of the cr-atp complex with phosphoribosylpyrophosphate synthetase from salmonella typhimurium. | 1979 | 222212 | |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| synthesis of adenosine 3':5'-cyclic monophosphate in salmonella typhimurium growing in continuous culture. | 1979 | 219134 | |
| 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 |
| 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 |
| 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 |
| [inner membrane structures and the electron paramagnetic resonance spectra of salmonella typhimurium cells after their interaction with nitroso compounds]. | 1978 | 214672 | |
| nucleoside diphosphokinase from salmonella typhimurium. | 1978 | 211385 | |
| phosphoribosylpyrophosphate synthetase (ribose-5-phosphate pyrophosphokinase) from salmonella typhimurium. | 1978 | 211378 | |
| alteration of the ability of liver microsomes to activate n-2-fluorenylacetamide to a mutagen of salmonella typhimurium during hepatocarcinogenesis. | 1978 | 208764 | |
| 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 |
| 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 |
| studies of the stereochemistry and of the role of metal ions in the mechanism of phosphoribosylpyrophosphate synthetase from salmonella typhimurium. | 1978 | 206555 | |
| 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 |
| 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 |
| 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 |
| 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 |
| role of arylhydroxamic acid acyltransferase in the mutagenicity of n-hydroxy-n-2-fluorenylacetamide in salmonella typhimurium. | 1978 | 203386 | |
| 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 |
| the metabolism of d-arabinose by salmonella typhimurium. | 1977 | 200704 | |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| development and applications of bacillus subtilis test systems for mutagens, involving dna-repair deficiency and suppressible auxotrophic mutations. | a mutagen-tester of bacillus subtilis was constructed and tested with known carcinogens. the parental strain ha101 of okubo and yanagida carrying suppressible nonsense mutations in his and met genes was transformed to carry an excision-repair deficiency mutation. the constructed strain tkj5211 showed a 20--30-fold higher sensitivity for his+ reversion than the parental strain when treated with uv and uv-mimetic chemicals but unchanged mutation frequency with x-rays and methyl methanesulfonate. t ... | 1977 | 191747 |
| 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 |
| 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 |
| 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 |
| 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 |
| 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 |
| [in vitro phagocytosis of salmonella typhimurium strains following treatment with various chemical substances]. | 1976 | 188309 | |
| 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 |
| fosfomycin resistance: selection method for internal and extended deletions of the phosphoenolpyruvate:sugar phosphotransferase genes of salmonella typhimurium. | selection for resistance to the antibiotic fosfomycin (fos; l-cis 1,2-epoxypropylphosphonic acid, a structural analogue of phosphoenolpyruvate) was used to isolate mutants carrying internal and extended deletions of varying lengths within the ptshi operon of salmonella typhimurium. strains carrying "tight" ptsi point mutations and all mutants in which some or all of the ptsi gene was deleted were fos resistant. in contrast, strains carrying ptsh point mutations were sensitive to fos. resistance ... | 1976 | 186449 |
| response of mouse liver glycogen cycle enzymes to endotoxin treatment. | the present study was undertaken to characterize endotoxin-induced changes in carbohydrate metabolism and more specifically, to determine the contribution of glycogenolysis to the loss of liver glycogen. female icr mice, fasted overnight, were injected with a median lethal dose (ld50, 9 mg/kg) of endotoxin extracted from salmonella typhimurium strain sr-11. glycogen synthase and glycogen phosphorylase activities were measured at 0.5 and 6 h after treatment. endotoxin treatment did not alter tota ... | 1976 | 185914 |
| ultrastructure of lipopolysaccharides of yersinia enterocolitica, salmonella typhimurium and escherichia coli. | the fine structure of isolated lipopolysaccharides (lps) from the rough and smooth form of an yersinia enterocolitica strain (ye 75 r/ye 75 s) and from smooth forms of salmonella typhimurium (s 1010) and escherichia coli (essen) were examined electron-microscopically by negative staining. partial denaturation of lps in tris-buffer with acid and/or polymyxin b treatment revealed a common structure of strandlike lps. electron-microscopically, lps-strands were found to consist of two identical sub- ... | 1976 | 185850 |
| effect of polymyxin on the outer membrane of salmonella typhimurium: freeze-fracture studies. | polymyxin-caused projections on the cell surface of salmonella typhimurium were seen as depressions in the outer concave fracture face and as protrusions in the outer convex fracture face, indicating participation of both leaflets of the outer membrane in these projections. | 1976 | 185199 |
| isolation and partial characterization of an argr mutant of salmonella typhimurium. | an arginine regulatory mutant (i.e., mutated in the argr gene) has been isolated from a strain of salmonella typhimurium lt2. the argr mutant was found to excrete arginine into the growth medium with glycerol but not glucose as carbon source. constitutive synthesis of arginine biosynthetic enzymes was observed. whereas previous results (a. t. abd-e1-a1 and j. l. ingraham, abstr. annu. meet. am. soc. microbiol. 1975, k169, p. 175) have shown constitutive synthesis of carbamyl phosphate synthetase ... | 1976 | 185197 |
| arginine-sensitive phenotype of mutations in pyra of salmonella typhimurium: role of ornithine carbamyltransferase in the assembly of mutant carbamylphosphate synthetase. | the phenotype of certain mutations in pyra, the gene encoding carbamylphosphate synthetase (cpsase), is expressed only in the presence od exogenous arginine. in unsupplemented media, synthesis of carbamylphosphate and growth was almost normal; in arginine-containing media, synthesis of carbamylphosphate stopped, as did growth, as a consequence of starvation for pyrimidine. genetic and biochemical evidence suggests that arginine exerts this inhibition by repressing the synthesis of ornithine carb ... | 1976 | 185193 |
| leakage of periplasmic enzymes from lipopolysaccharide-defective mutants of salmonella typhimurium. | mutants of salmonella typhimurium with defects in the heptose region of the lipopolysaccharide (lps) molecule (heptose-deficient, chemotype re) leak periplasmic enzymes (acid phosphatase (ec 3.1.3.2), cyclic phosphodiesterase, ribonuclease i (ec 3.1.4.22), and phosphoglucose isomerase (ec 5.3.1.9) (pgi is at least partially periplasmic in e. coli and s. typhimurium; see below)) and do not leak an internal enzyme (glucose-6-phosphate dehydrogenase) into the growth medium. the extent of this leaka ... | 1976 | 184900 |
| methionine-repressible homoserine dehydrogenase of serratia marcescens: purification and properties. | serratia marcescens sa-3 possesses two homoserine dehydrogenases and neither has any aspartokinase activity unlike the case of escherichia coli enzymes. the two enzymes have been separated. one of them is active with either nad+ or nadp+ and has been purified about 180-fold to homogeneity. this enzyme is completely repressed by the presence of 1 mm methionine or homoserine in the growth medium, but its activity is unaffected by any amino acid of the aspartate family either singly or together. in ... | 1976 | 184374 |
| action of polymyxin b on bacterial membranes. binding capacities for polymyxin b of inner and outer membranes isolated from salmonella typhimurium g30. | radioactive mono-n-acetyl-14c-polymyxin b or natural polymyxin b are within 60 s absorbed by isolated inner (cytoplasmic) and outer membranes from salmonella typhimuriumg30. the sigmoidal binding isotherms indicate saturation of inner and outer membranes with approximately 30 and 60 nmoles polymyxin b bound per mg membrane, respectively. based on the known content of these membranes in lipopolysaccharide, phosphatidylglycerol, cardiolipin and phosphatidylethanolamine, a calculation of the theor ... | 1976 | 183617 |
| non-specific immunity after local immunization. | the most important advantage of local immunization is the non-specific effect. the active protection test in mice shows an immunity against oral infection with virulent salmonella typhimurium bacteria after oral immunization with heterologous inactivated enterobacteria. we observed the same non-specific protection in a viral model. after oral immunization with inactivated s. typhimurium bacteria, the mice are protected against oral infection with a virulent parapoliomyelitis virus. in the phagoc ... | 1976 | 182583 |
| simultaneous selection of mutants in gluconeogenesis and nucleoside catabolism in salmonella typhimurium. | penicillin selection in minimal thymidine medium, used to select mutants in deoxynucleoside catabolism, also yields a high percentage (37%) of mutants in fructose diphosphatase. the expression of the deo regulon is retarded in the mutants defective in the glyconeogenic pathway. | 1976 | 182268 |
| the effect of bacterial infections on ketone concentrations in rat liver and blood and on free fatty acid concentrations in rat blood. | the concentrations of cytoplasmic lactate and pyruvate and the nad+/nadh ratio and the concentrations of mitochondrial acetoacetate, beta-hydroxybutyrate, and the nad+/nadh ratio were determined in normal, fed, and fasted rats, and in rats infected with streptococcus pneumoniae, francisella tularensis, and salmonella typhimurium. the various infections were found to have little or no effect on the cytoplasmic parameters. in normal rats, fasting caused a marked increase in blood and hepatic keton ... | 1976 | 181658 |
| effects of crp mutations on adenosine 3',5'-monophosphate metabolism in salmonella typhimurium. | wild-type salmonella typhimurium could not grow with exogenous cyclic adenosine 3',5'-monophosphate (amp) as the sole source of phosphate, but mutants capable of cyclic amp utilization could be isolated provided the parental strain contained a functional cyclic amp phosphodiesterase.all cyclic amp-utilizing mutants had the growth and fermentation properties of cyclic amp receptor protein (crp) mutants, and some lacked cyclic amp binding activity in vitro. the genetic defect in each such mutant w ... | 1976 | 179973 |
| inhibition of growth and aspartokinase activity of salmonella typhimurium by thialysine. | thialysine (s-2-aminoethyl cysteine) is an analog of lysine and has been reported to inhibit the lysyl-trna synthetase activity of escherichia coli. this analog inhibits the growth of salmonella typhimurium when added to glucose minimal medium at concentrations of 1.25 mm or greater. the addition of lysine with thialysine restores the normal growth rate, whereas, methionine, valine, or leucine each enhances the growth inhibition casued by thialysine. enzyme assays demonstrate that thialysine inh ... | 1976 | 179582 |
| 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 |
| growth rate modulation of four aminoacyl-transfer ribonucleic acid synthetases in enteric bacteria. | the specific activities of arginyl- glutamyl- seryl-, and valyl-transfer ribonucleic acid (trna) synthetases were measured in the wild-type and mutant strains of salmonella typhimurium lt2 and escherichia coli b/r. in media restricted only by carbon and energy source availability, the specific activities of all four enzymes were proportional to the growth rate, with the exception of seryl-trna synthetase in s. typhimurium, which remained essentially constant. structural gene densities were calcu ... | 1976 | 177401 |
| action of polymyxin b on bacterial membranes: phosphatidylglycerol- and cardiolipin-induced susceptibility to polymyxin b in acholeplasma laidlawii b. | to identify the polymyxin receptor molecules in the membranes of living microorganisms, fusion of intact acholeplasma laidlawii b with lipid vesicles was investigated according to the procedure of grant and mcconnell (1973). the naturally polymyxin-resistant a. laidlawii b was treated with phospholipid vesicles prepared from purified phospholipids of the polymyxin-susceptible salmonella typhimurium g30. a. laidlawii b absorbed between 15 and 45% of its own lipid content of the added tritium-labe ... | 1976 | 176930 |
| cysteine biosynthesis in salmonella typhimurium: the presence of atp-sulfurylase and aps-kinase in various cysteine-requiring mutants. | enzymatic tests were performed on a series of cysteine-requiring mutants for the presence of the sulfate activating enzymes. atp-sulfurylase (sulfate adenylyltransferase ec 2.7.7.4) and aps-kinase (adenylylsulfate kinase ec 2.7.1.25). the enzymatic products adenosine 5'-[35s]sulfatophosphate and adenosine 3'-phosphate 5'-[35s]sulfatophosphate were identified by paper electrophoresis and measured quantitatively without elution from the paper. cys mutants mapping in cistrons, a, h, i, j, g, and ea ... | 1975 | 173451 |
| pathogenesis of salmonella-mediated intestinal fluid secretion. activation of adenylate cyclase and inhibition by indomethacin. | salmonella typhimurium, an organism that invades intestinal mucosa but does not elaborate a traditional enterotoxin, evokes ileal secretion by causing alterations in active sodium and chloride transport mechanisms. to evaluate the possibility that these changes in transport might be related to the adenylate cyclase-cyclic amp or na+-k+-adenosine triphosphatase (atpase) systems, mucosal adenylate cyclase, camp phosphodiesterase, na+-k+ and mg++ atpase activities, and camp concentrations were meas ... | 1975 | 172399 |
| host influence on the activity of genes c1 and c3 in regulating the decision between lysis and lysogency in bacteriophage p22. | a polymyxin b-sensitive mutant of salmonella typhimurium (pox-1) channels all infecting wild-type p22 toward lysogenization. the efficiency of this channeling is sufficiently high that p22c+ (wild type) cannot form plaques on pox-1; phage mutants defective in repressor synthesis (p22c1, c2, c3) or refractory toward repressor (p22vir b) can form plaques. the lytic growth of all phages which have a functional c1 gene is retarded in pox-1; this retardation is seen even in phages which cannot make r ... | 1975 | 171449 |
| altered dna synthesis in a mutant of salmonella typhimurium that channels bacteriophage p22 toward lysogeny. | pox-1, a mutant of salmonella typhimurium, strongly channels p22 toward lysogeny. viral dna synthesis in this slow-growing mutant is delayed to a greater extent than viral protein synthesis. the relative enhancement of c2 repressor synthesis results in much higher repressor/dna synthesis ratios in pox-1 than in wild-type cells. this probably accounts for the high frequency of lysogenization. | 1975 | 171446 |
| mutants of salmonella typhimurium responding to cysteine or methionine: their nature and possible role in the regulation of cysteine biosynthesis. | nineteen mutants of salmonella typhimurium responding to either cysteine or methionine (cym) have been identified amongst cysteine (cys) and methionine (met) auxotrophs. their growth responses to known intermediates in the related pathways of cysteine and methionine biosynthesis and complementation patterns in abortive transduction tests divided the mutants into six groups. results of conjugation, cotransduction and deletion mapping experiments substantiated these groups, each of which carried a ... | 1975 | 170364 |
| regulation of intracellular adenosine cyclic 3':5'-monophosphate levels in escherichia coli and salmonella typhimurium. evidence for energy-dependent excretion of the cyclic nucleotide. | sugars and other energy sources were found to lower intracellular concentrations of adenosine 3':5'-monophosphate (cyclic amp) in strains of escherichia coli and salmonella typhimurium which were deficient for cyclic amp phosphodiesterase. this effect required the presence of the specific transport system responsible for entry of that sugar into the cell and depended on the intracellular catabolic enzymes. metabolizable sugars were more effective than nonmetabolizable sugars in reducing cellular ... | 1975 | 170265 |
| studies of the quaternary structure and the chemical properties of phosphoribosylpyrophosphate synthetase from salmonella typhimurium. | phosphoribosylpyrophosphate (prpp) synthetase (ec 2.7.6.1) was purified to virtual homogeneity from salmonella typhimurium cells by a modification of previously published procedures. the molecular weight of the subunit was determined to be 31,000 +/- 3,000 by polyacrylamide gel electrophoresis in sodium dodecyl sulfate and sedimentation equilibrium analysis of the enzyme dissolved in 6 m guanidine hydrochloride. the amino acid composition of the enzyme was determined. proline was identified as t ... | 1975 | 170262 |
| characterization of monkey peripheral neutrophil granules during infection. | rhesus monkey (macaca mulatta) neutrophils were shown to contain the azurophilic granule maker enzymes myeloperoxidase and beta-glucuronidase but were deficient in the specific granule markers alkaline phosphatase (akp) and lysozyme. isopycnic centrifugation of leukocyte homogenates on linear sucrose gradients resulted in cosedimentation of myeloperoxidase and beta-glucuronidase with an equilibrium density of 1.18. after an intravenous inoculation of monkeys with salmonella typhimurium akp activ ... | 1975 | 170208 |
| regulation of gmp reductase in salmonella typhimurium. | the levels of guanosine 5'-phosphate reductase (ec 1.6.6.8) in salmonella typhimurium appear to be modulated by changes in the ratio of the adenine and guanine nucleotide pools. alterations of this ratio may be induced by high levels of guanosine in the culture medium or by genetic lesions in one of several purine interconversion enzymes, such as pur a or pur b mutants. the induction of the reductase requires transcription and translation processes and, in contrast to earlier observation with es ... | 1975 | 169910 |
| action of polymyxin b on bacterial membranes: morphological changes in the cytoplasm and in the outer membrane of salmonella typhimurium and escherichia coli b. | though the primary action of the cationic antibiotic polymyxin b is against the membrane of susceptible bacteria, severe morphological changes are detected in the cytoplasm. using fluorescence microscopy and a mono-n-dansyl-polymyxin b derivative, we could demonstrate aggregations of the antibiotic with cellular material, possibly nucleic acids and/or ribosomes. these aggregations were only produced by minimum inhibitory or higher concentrations of the antibiotic as shown with salmonella and esc ... | 1975 | 169730 |
| coordinate regulation of adenylate cyclase and carbohydrate permeases by the phosphoenolpyruvate:sugar phosphotransferase system in salmonella typhimurium. | adenylate cyclase (ec 4.6.1.1) and several carbohydrate permeases are inhibited by d-glucose and other substrates of the phosphoenolpyruvate:sugar phosphotransferase system. these activities are coordinately altered by sugar substrates of the phosphotransferase system in a variety of bacterial strains which contain differing cellular levels of the protein components of the phosphotransferase system: enzyme i, a small heat-stable protein, and enzyme ii. it is suggested that the activities of aden ... | 1975 | 169265 |
| tryptophan biosynthesis in salmonella typhimurium: location in trpb of a genetic difference between strains lt2 and lt7. | salmonella typhimurium prototrophs carrying a trpr mutation synthesize tryptophan biosynthetic enzymes constitutively. when feedback inhibition of anthranilate synthetase but not 5'-phosphoribosylpyrophosphate phosphoribosyltransferase activity was by-passed by growing cells on media supplemented with anthranilic acid, all trpr prototrophs overproduced and excreted tryptophan. however, the rate of tryptophan production depended on both the ancestry of the trpr strain and the integrity of its trp ... | 1975 | 169230 |
| pyrr identical to pyrh in salmonella typhimurium: control of expression of the pyr genes. | mutants of salmonella typhimurium showing constitutive synthesis of the pyrimidine biosynthetic enzymes coded for by the pyra-f genes (g. a. o'donavan and j. c. gerhart, 1972) have been reinvestigated. the high rate of expression of the pyrb-f genes in these mutants as well as their pyrimidine excretion is shown to be due to mutations in the gene pyrh encoding uridine 5'-monophosphate kinase. thus, the term pyrr used for these mutants should be replaced by the designation pyrh. | 1975 | 169229 |
| cyclic 3', 5'-adenosine monophosphate phosphodiesterase mutants of salmonella typhimurium. | positive selection procedures for mutants of salmonella typhimurium lacking cyclic 3', 5'7-adenosine monophosphate (camp) phosphodiesterase have been devised. the gene (cpd) coding for this enzyme has been located on the chromosome and shown to be 25% co-transducible with metc using phage p22. the mutants have been used to investigate the role of the enzyme in the control of genes whose expression is known to be dependent on camp. significant alterations in the regulation of some but not others ... | 1975 | 168178 |
| mutagenicity testing with salmonella typhimurium strains. ii. the effect of unusual phenotypes on the mutagenic response. | the enhanced sensitivity of some salmonella typhimurium strains to the mutagenic action of a number of chemicals appears to be due to the defect in the uvrb gene product and not to an inability to produce h-2-s or to the absence of formic acid hydrogenlyase which also characterizes these strains. | 1975 | 167280 |
| inactivation of salmonella phosphoribosylpyrophosphate synthetase by oxidation of a specific sulfhydryl group with potassium permanganate. | phosphoribosylpyrophosphate synthetase from salmonella typhimurium contains four cysteine residues per subunit. three of these react readily with 5, 5'-dithiobis(2-nitrobenzoic acid) (dtnb), forming an active derivative with kinetic and physical properties similar to the native enzyme, but one reacts only under denaturing conditions. stoichiometric amounts of kmno4 inactivate the dtnb-treated enzyme. the loss of activity is correlated with the oxidation of the remaining cysteinyl group to cystei ... | 1975 | 167011 |
| carbamylphosphate synthetase from salmonella typhimurium. regulations, subunit composition, and function of the subunits. | carbamylphosphate synthetase was purified to homogeneity from a derepressed strain of salmonella typhimurium by a procedure based on affinity chromatography employing immobilized glutamine. the enzyme catalyzes the synthesis of carbamylphosphate from either ammonia or glutamine together with atp and bicarbonate. the atp saturation curve of either nitrogen donor is sigmoidal (n equals 1.5) but the affinity for atp is higher with ammonia. in addition to the feedback inhibition by ump and activatio ... | 1975 | 166993 |
| mechanism of the suppressive effect of interferon on antibody synthesis in vivo. | mouse interferon preparations significantly suppress the in vivo antibody response to sheep red blood cells (srbc), a thymus-dependent antigen, and to salmonella typhimurium lipopolysaccharide (lps), a thymus-independent antigen. it is also possible to effect the late responses of antigen sensitive "memory" cells observed during secondary immunization by administration of interferon prior to primary immunization. the immunosuppressive activity of interferon was time- and dose-dependent. maximum ... | 1975 | 163863 |
| control of expression of the pyr genes in salmonella typhimurium: effects of variations in uridine and cytidine nucleotide pools. | the differential rate of synthesis of five of the pyrimidine biosynthetic enzymes coded for by pyrb-f, and the endogenous concentrations of the individual pyrimidine nucleotides were determined in specially constructed mutants of salmonella typhimurium. in the mutants employed the different pyrimidine nucleotide pools may be manipulated individually during exponential growth. the results obtained indicate the following. (i) the expression of pyrb, pyre, and pyrf is controlled by a uridine nucleo ... | 1975 | 163814 |
| inactivation of viruses and bacteria by ozone, with and without sonication. | selected organisms with public health significance were placed in a reaction chamber for treatment by ozonation, by ozonation and sonication, by sonication, or by sonication during oxygenation. vesicular stomatitis virus, encephalomyocarditis virus, gdvii virus, staphylococcus aureus, pseudomonas fluorescens, salmonella typhimurium, enteropathogenic escherichia coli, vibrio cholerae, and shigella flexneri were inactivated by treatment with ozone. when microorganisms were suspended in phosphate-b ... | 1975 | 163616 |
| [results of 28 years of observations of the circulation of biologically nonuniform varieties of salmonella typhimurium]. | 1978 | 161090 | |
| gene for the rna polymerase sigma subunit mapped in salmonella typhimurium and escherichia coli by cloning and deletion. | the genes for the rna polymerase sigma subunit (rpod) and dna primase (dnag) of salmonella typhimurium have been cloned into lambda vectors. combined restriction, deletion and functional analysis of the cloned fragment allows us to map the genes precisely on the fragment, establishes the direction in which rpod is transcribed, and reveals the existence of at least one new gene in the vicinity. a closely homologous, smaller fragment of escherichia coli dna, also cloned into lambda, contains rpod ... | 1979 | 160566 |
| response to a metal ion-citrate complex in bacterial sensing. | salmonella typhimurium responds chemotactically to gradients of divalent cations in the presence of citrate ions. the actual chemoeffector is the citrate-metal ion complex, which acts as an attractant. citrate (which is also a chemoeffector for salmonella) and the citrate-metal ion complex are recognized by different receptors. the response of salmonells, which can transport citrate through its membrane, is quite different than that of escherichia coli, which cannot. | 1979 | 160411 |
| tumor induction in swiss mice by filtrable agent and salmonella typhimurium. | combined inoculation of a cell-free extract of leukotic tissue of d103 mice and salmonella typhimurium into adult swiss mice induced leukosis and solid tumors. the induced solid tumors were histologically multifarious, and were transplantable in swiss mice, but not in other strains of mice. | 1979 | 160187 |