| phospholipase d activity of gram-negative bacteria. | a phospholipase hydrolyzing cardiolipin to phosphatidic acid and phosphatidyl glycerol was characterized in gram-negative bacteria but was absent in preparations of gram-positive bacteria, saccharomyces cerevisiae, and rat liver mitochondria. in cell-free extracts of escherichia coli, salmonella typhimurium, proteus vulgaris, and pseudomonase aeruginosa, this cardiolipin-hydrolyzing enzyme had similar ph and mg2+ requirements and displayed a specificity which excluded phosphatidyl glycerol and p ... | 1975 | 360 |
| expression of the hut operons of salmonella typhimurium in klebsiella aerogenes and in escherichia coli. | the normal hut (histidine utilization) operons, as well as those with mutations affecting the regulation of their expression, of salmonella typhimurium were introduced on an f' episome into cells of s. typhimurium and klebsiella aerogenes whose chromosomal hut genes had been deleted and into cells of escherichia coli, whose chromosome does not carry hut genes. the episomal hut operons respond in a manner very similar to induction and catabolite repression in all three organisms. the small differ ... | 1975 | 362 |
| regulation of the hut operons of salmonella typhimurium and klebsiella aerogenes by the heterologous hut repressors. | in merodiploid strains of klebsiella aerogenes with chromosomal hut genes of k. aerogenes and episomal hut genes of salmonella typhimurium, the repressor of either species can regulate the hut operons of the other species. the repression exerted by the homologous repressor on the left-hand hut operon is, in both organisms, stronger than that exerted by the heterologous repressor. | 1975 | 363 |
| 3-deoxy-d-arabino-heptulosonic acid 7-phosphate synthase mutants of salmonella typhimurium. | the first committed step of aromatic amino acid biosynthesis in salmonella typhimurium was shown to be catalyzed by three isoenzymes of 3-deoxy-d-arabino-heptulosonic acid 7-phosphate (dahp) synthase. mutations in each of the genes specifying the isoenzymes were isolated and mapped. arog, the structural gene for the phenylalanine-inhibitable isoenzyme, was linked to gal, and aroh, the structural gene for the tryptophan-inhibitable isoenzyme, was linked to aroe. arof, the structural gene for the ... | 1975 | 365 |
| transport and metabolism of vitamin b6 in salmonella typhimurium lt2. | salmonella typhimurium lt2 concentrates radioactivity intracellularly from 3hpyridoxal or 3hpyridoxine up to 25 times the external concentration. after 1 min of uptake intracellular radioactivity is found as phosphorylated vitamin b6. the process is sensitive to temperature and is maximally active at ph 8.1, but under the conditions tested it is insensitive to monovalent cations or metabolic inhibitors, and does not require an exogenous energy source. the km values for uptake of pyridoxine and p ... | 1976 | 2599 |
| histidyl transfer ribonucleic acid synthetase from salmonella typhimurium. interaction with substrates and atp analogues. | structural requirements for substrate binding to histidyl-trna synthetase from salmonella typhimurium have been investigated using atp analogues. ki values and the relative binding affinity of the enzyme for these analogues have been determined in the trna aminoacylation reaction. the enzyme is highly specific for atp: no binding was found for gtp, ctp, ttp and utp. datp is a very poor substrate for acylation of trna, with a km 40-fold higher than that of atp. binding of adenosine 5'-triphosphat ... | 1976 | 3414 |
| transduction of chromosomal genes between enteric bacteria by bacteriophage p1. | we have used p1 transduction to create intergeneric hybrid strains of enteric bacteria by moving the gena and hut genes between klebsiella aerogenes, escherichia coli and salmonella typhimurium. the use of e. coli as the recipient in such transductions permits the construction of episomes and specialized transducing phage containing non-e. coli material. the effect of host restriction modification and deoxyribonucleic acid homology on the frequency of intergeneric transduction of these loci has ... | 1976 | 3494 |
| changes in bile physicochemical indexes in experimental salmonella typhimurium carrier state. | | 1975 | 3718 |
| envelope mutation promoting autolysis in salmonella typhimurium. | two strains independently isolated in salmonella typhimurium display abnormal autolytic activity when nutrient broth becomes alkaline. they also show increased sensitivity to deoxycholate, edta, and sodium dodecyl sulfate. response to acridine orange remains normal. in both strains a single stable mutation is responsible for all the changes. the same gene, called envd, appears to be involved in both mutant strains. envd has been located at minute 33 of the salmonella genetic map, between markers ... | 1976 | 4722 |
| nonspecific bactericidal activity of the lactoperoxidases-thiocyanate-hydrogen peroxide system of milk against escherichia coli and some gram-negative pathogens. | two strains of escherichia coli and one strain each of salmonella typhimurium and pseudomonas aeruginosa were killed by the bactericidal activity of the lactoperoxidase-thiocyanate-hydrogen peroxide system in milk and in a synthetic medium. h2o2 was supplied exogenously by glucose oxidase, and glucose was produced at a level which was itself noninhibitory. two phases were distinguished: the first phase was dependent on the oxidation of scn(-) by lactoperoxidase and h2o2, which was reversed by re ... | 1976 | 5374 |
| defective lipid disposal mechanisms during bacterial infection in rhesus monkeys. | mechanisms producing hypertriglyceridemia during bacterial sepsis have not been well defined. in this study lipid disposal mechanisms were assessed in 76 infected and 19 control male rhesus monkeys by the ability to dispose of triglycerides after: (1) oral lipid loading; (2) intravenous lipid loading; and (3) by lipolytic enzyme activity tests as measured by postheparin lipolytic activity (phla). studies were performed both before and 48 hr after intravenous inoculation with either salmonella ty ... | 1976 | 5648 |
| enzymic and molecular properties of base-plate parts of bacteriophage p22. | using 14c-labeled salmonella bacterial cells as the substrate, the enzymic and molecular properties of the base-plate parts of phage p22 were studied. the base-plate part consisted of a single protein species which cleaved extensively the o-antigen of salmonella typhimurium, salmonelly schottmuellerie and with somewhat slower rate that of salmonella typhi, releasing oligo-saccharide products with rhamnose at the reducing end. much less cleavage was observed with a strain of s. typhimurium lysoge ... | 1976 | 6284 |
| regulation of histidase synthesis in intergeneric hybrids of enteric bacteria. | regulation of the expression of the histidase coded by hutk of klebsiella aerogenes in salmonella typhimurium and in escherichia coli and of the expression of the histidase coded by huts of s. typhimurium in e. coli was investigated. the hutk histidase was found to be sensitive to catabolite repression in k. aerogenes and in e. coli, but insensitive to catabolite repression in s. typhimurium; huts histidase has previously been shown to be catabolite sensitive in all three organisms. the expressi ... | 1976 | 6426 |
| kinetic properties of serratia marcescens adenosine 5'-diphosphate glucose pyrophosphorylase. | the regulatory properties of partially purified adenosine 5'-diphosphate-(adp) glucose pyrophosphorylase from two serratia marcescens strains (atcc 274 and atcc 15365) have been studied. slight or negligible activation by fructose-p2, pyridoxal-phosphate, or reduced nicotinamide adenine dinucleotide phosphate (nadph) was observed. these compounds were previously shown to be potent activators of the adpglucose pyrophosphorylases from the enterics, salmonella typhimurium, enterobacter aerogenes, e ... | 1976 | 6432 |
| the synthesis and properties of n6-substituted 2-amino-purine derivatives. | 1. the synthesis, ultraviolet absorption spectra, and behaviour in alkali of n6-methoxy-, n6-methyl, hydroxy-, and n6-hydroxy-2-aminopurines have been described 2. n6-methoxy-2-aminopurine riboside 5'-pyrophosphate has been prepared and used for polymerization with polynucleotide phosphorylase. 3. the copolymer containing n6-methoxy-2-aminopurine riboside and adenosine residues has been obtained; attempts to synthesize the homopolymer have not been successful. 4. all the purine analogues synthes ... | 1976 | 7092 |
| deoxyribonucleic acid-binding studies on the hut repressor and mutant forms of the hut repressor of salmonella typhimurium. | in salmonella typhimurium the genes coding for the enzymes of histidine utilization (hut) are clustered in two adjacent operons, hutmigc and hut(p,r,q)uh. a single repressor, the product of the c gene, regulates both operons by binding at two operator sites, one near m and one in (p,r,q). the deoxyribonucleic acid (dna)-binding activity of the repressor was measured using dna's containing separate operators. the repressor had greater activity when assayed using dna containing the operator of the ... | 1976 | 8423 |
| the regulation of glutamine transport and glutamine synthetase in salmonella typhimurium. | transport of glutamine by the high-affinity transport system is regulated by the nitrogen status of the medium. with high concentrations of ammonia, transport is repressed; whereas with casamino acids, transport is elevated, showing behaviour similar to glutamine synthetase. a glutamine auxotroph, lacking glutamine synthetase activity, had elevated transport activity even in the presence of high concentrations of ammonia (and glutamine). this suggests that glutamine synthetase is involved in the ... | 1976 | 8587 |
| prevention of benzo(a)pyrene-induced mutagenicity by homogeneous epoxide hydratase. | benzo(a)pyrene and benz(a) anthrancene which, in contrast to the k-region epoxides benzo(a)pyrene 4,5-oxide and benz(a)anthracene 5,6-oxide, are not mutagenic to salmonella typhimurium ta 1537 in the absence of mammalian enzyme preparations, were activated by liver microsomes from c3h mice, which had not received any pretreatment, to mutagens reverting this tester strain to histidine prototrophy. addition of epoxide hydratase inhibitors greatly increased this mutagenicity and addition of pure ep ... | 1976 | 10260 |
| unique aspects of the regulation of the aspartate transcarbamylase of serratia marcescens. | aspartate trancarbamylase (atc ase; ec 2.1.3.2) from serratia marcescens hy has been purified 134-fold. its properties are unique. unlike the atcase from escherichia coli and salmonella typhimurium, the s. marcescens hy enzyme activity is not feedback inhibited by any purine or pyrimidine nucleotide effectors; instead, the enzyme is activated by both cytidine 5'-triphosphate and adenosine 5'-triphosphate. like the atcase from e. coli and s. typhimurium, adenosine 5'-triphosphate alters the s0.5 ... | 1976 | 11207 |
| formation of mutagenic n-nitroso compounds from the pesticides prometryne, dodine and carbaryl in the presence of nitrite at ph 1. | environmental chemicals including pesticides carrying secondary and tertiary amino groups are suggested to be a health hazard to man since potentially carcinogenic nitroso compounds may be formed in the presence of nitrite at low ph values resembling conditions in the human stomach. nitrosation of the isopropylamino-triazine prometryne, the n-dodecyl guanidine dodine and the n-methylcarbamate carbaryl was investigated in the presence of hcl and acetic acid at ph 1 and excess sodium nitrite for 4 ... | 1976 | 12468 |
| the influence of ph on the effects of 2,4-d (2,4-dichlorophenoxyacetic acid, na salt) on saccharomyces cerevisiae and salmonella typhimurium. | the genetic effects of 2,4-d (2,4-dichlorophenoxyacetic acid, na salt) have been investigated in cells of the yeast saccharomyces cerevisiae and of the bacterium salmonella typhimurium in experiments in vitro and in vivo. experiments in vitro showed that the killing of both yeast and bacteria is dependent on the ph in the treatment solution of 2,4-d. a dose-dependent increase of the frequency of mitotic gene conversion and mitotic recombination in yeast was observed at ph 4.50 and 4.30. in exper ... | 1977 | 15215 |
| mutagenicity of halogenated ether anesthetics. | an in vitro microbial assay system employing two histidine-dependent strains of salmonella typhimurium, ta1535 and ta100, was used to test the mutagenicities of enflurane, methoxyflurane, isoflurane and fluroxene. enflurane, isoflurane and fluroxene in concentrations ranging from 0.01 to 30 per cent and methoxyflurane in concentrations ranging from 0.01 to 7 per cent were incubated with bacteria in the presence or absence of homogenates of liver prepared from rats pretreated with the enzyme indu ... | 1977 | 15474 |
| the product of a newly identified gene, ginf, is required for synthesis of glutamine synthetase in salmonella. | the product of a newly identified gene, glnf, which is distinct from the glutamine synthetase structural gene (glna), is required for synthesis of glutamine synthetase l-glutamate:ammonia ligase (adp-forming), ec 6.3.1.2 in salmonella typhimurium and probably in escherichia coli. salmonella strains with icr (2-chloro-6-methoxy-9-3-(2-chloroethyl)aminopropylaminoacridine dihyodrochloride)-induced (frameshift) mutations in glnf are glutamine auxotrophs; they have less than 10% oof wild-type glutam ... | 1977 | 16262 |
| regulation of enzyme synthesis by the glutamine synthetase of salmonella typhimurium: a factor in addition to glutamine synthetase is required for activation of enzyme formation. | in klebsiella aerogenes but not in salmonella typhimurium glutamine synthetase can function during nitrogen-limited growth to increase the rate of synthesis of histidase from the hut genes of s. typhimurium 15-59 (huts. 15-59). formation of proline oxidase is also not increased in nitrogen-limited cultures of s. typhimurium. however, in hybrid strains of escherichia coli or k. aerogenes, the glutamine synthetase of s. typhimurium activates synthesis of histidase from the huts. 15-59 genes. appar ... | 1977 | 16868 |
| phosphoprotein phosphatase activity associated with the cytoplasmic membrane of salmonella typhimurium and escherichia coli. | membrane-associated phosphoprotein phosphatase activity was demonstrated in extracts of salmonella typhimurium and escherichia coli. the active protein could be extracted from the membrane as a large water-soluble complex (mr greater than 150,000). maximal activity was observed at ph 6 to 7 in the presence of a divalent cation. the enzyme appears to be distinct from previously described phosphatases. | 1977 | 16933 |
| aryl and heterocyclic diazo compounds as potential environmental electrophiles. | 4-aminoimidazole-5-carboxamide, a component of human urine derived from the de novo purine biosynthetic pathway, was evidenced to undergo in vivo diazotization in rats following its sequential administration with nano2. the diazotization product, 4-diazoimidazole-5-carboxamide, undergoes intramolecular cyclization to yield 2-azahypoxanthine, the urinary presence of which was confirmed mass spectrometrically. 4-diazoimidazole-5-carboxamide demonstrated dose-related mutagenicity in salmonella typh ... | 1977 | 17015 |
| mutagenicity of 22 n-nitrosamides and related compounds for salmonella typhimurium ta1535. | twenty-two n-nitrosamides and related compounds, including 14 nitrosoureas, 5 nitrosocarbamates, and one nitrosocyanamide, were tested at various concentrations for mutagenic activity towards salmonella typhimurium ta1535 without the use of microsomes. the ether-water partition coefficient, solubility in water, and half-life in aqueous solution were also measured. twenty compounds were mutagenic, with "standard mutagenic concentrations" (i.e. those producing 100 mutants/dish) of 0.0024--6500 mic ... | 1977 | 17832 |
| nitrosation in vitro and in vivo by sodium nitrite, and mutagenicity of nitrogenous pesticides. | 37 nitrogenous pesticides, belonging to the chemical groups of amides, carbamates and ureas, were nitrosated with sodium nitrite in vitro. the nitrosated compounds were tested for mutagenic activity in the bacterial spot test with salmonella typhimurium his g 46. those pesticides reacting positively in this test after nitrosation were then fed to mice in combination with sodium nitrite in order to assess the formation and mutagenicity of these nitroso compounds in vivo. with the already known ex ... | 1977 | 17833 |
| characterization of salmonella typhimurium mutants with altered glutamine synthetase activity. | a number of glutamine auxotrophs of salmonella typhimurium were isolated and characterized genetically. three of the mutations appear to be closely linked and are complemented by episomes carrying the glna region of escherichia coli. the lesions in these strains are approximately 20% linked by p1 transduction with a mutation in the rha gene, but are unlinked to ilv. another mutation causing glutamine auxotrophy in strain jb674 is genetically distinct from the others. strain jb674 grown in glucos ... | 1977 | 19344 |
| inhibitory action of fatty acids on the growth of neisseria gonorrhoeae. | fatty acids of various chain lengths (c(1) to c(24)) were examined for their effects on growth, oxygen consumption, and in vitro reduced nicotinamide adenine dinucleotide oxidase activity of neisseria gonorrhoeae cs-7. the growth inhibition caused by saturated fatty acids increased with increasing chain length to a maximum with palmitic acid (c(16)). stearic acid (c(18)) and longer saturated fatty acids showed little inhibition of growth. however, unsaturated fatty acids of chain length c(16) to ... | 1977 | 19358 |
| glutamine synthetase from salmonella typhimurium: manganese(ii), substrate, and inhibitor interaction with the unadenylylated enzyme. | | 1977 | 20051 |
| the n4-hydroxycytidine reduction system in toluenized cells of salmonella typhimurium. | 1. enzymatic reduction of n4-hydroxycytidine to cytidine in salmonella typhimurium is highly specific. the reaction occurs only at the nucleoside level. free base or its 1-methyl analogue is not reduced. 2. the ph optimum shows a broad plateau with a maximum at ph 7.0. the apparent km value, estimated in the toluene-treated cells, is 4.8 mm and vmax 1.4 nmoles/min/mg of wet bacterial weight. the reaction is nadh-dependent, although in toluenized bacterial cells it can occure without addition of ... | 1977 | 22212 |
| biochemical-genetic study of the first enzyme of histidine biosynthesis in salmonella typhimurium: substrate and feedback binding regions. | twenty-five strains of salmonella typhimurium containing different mutations in the first gene of histidine biosynthesis were studied to correlate regions of the genetic map with biochemical functions. these strains contained either missense, double-frameshift, or suppressed nonsense mutations, all of which resulted in altered, though active, enzymes. each mutant enzyme was assayed for activity in the presence of varying concentrations of the feedback inhibitor l-histidine or the substrates atp ... | 1978 | 22534 |
| energetics of galactose, proline, and glutamine transport in a cytochrome-deficient mutant of salmonella typhimurium. | the effect of inhibitors and uncouplers on the osmotic shock-sensitive transport systems for glutamine and galactose (by the beta-methyl galactoside permease) was compared to their effect on the osmotic shock-resistant proline and galactose permease systems in cytochrome-deficient cells of salmonella typhimurium sasy28. both osmotic shock-sensitive and -resistant systems were sensitive to uncouplers and to inhibitors of the membrane-bound ca2+, mg2+-activated adenosine triphosphatase. this sugge ... | 1977 | 22779 |
| surface-charge characteristics of smooth and rough salmonella typhimurium bacteria determined by aqueous two-phase partitioning and free zones electrophoresis. | aqueous biphasic partitioning of salmonella typhimurium s and r bacteria in a system containing 6.2 per cent (w/w) dextran 500 and 4.4 per cent (w/w) poly(ethyleneglycol) 6000 (peg) was similar to the partition of the corresponding surface lipopolysaccharide (lps). further partition analysis with charged peg showed that s bacteria and their lps exposed very little charge, whereas r bacteria and their lps showed a conspicuous negative charge at neutral ph. free zone electrophoresis also indicated ... | 1977 | 23649 |
| bactericidal activity of specific and azurophil granules from human neutrophils: studies with outer-membrane mutants of salmonella typhimurium lt-2. | extracts of specific granules and azurophil granules from human neutrophils were tested for their bactericidal activity against various lipopolysaccharide mutants of salmonella typhimurium lt-2. three purified granule populations, one specific and two azurophil, were obtained by isopycnic centrifugation of homogenized neutrophils. each was extracted with 0.2 m acetate buffer (ph 4), and the extracts were dialyzed against phosphate-buffered saline (ph 7) to remove acetate. these extracts containe ... | 1978 | 24000 |
| the mutagenic effect of 1,2-dichloroethane on salmonella typhimurium i. activation through conjugation with glutathion in vitro. | one of the main components in the waste products from vinyl chloride industries (edc-tar), is ethylene dichloride (1,2-dichloroethane). this compound has been tested for mutagenicity on salmonella typhimurium ta 1535. it is concluded that 1,2-dichloroethane gives a weak direct mutagenic effect, which is enhanced by addition of the postmitochondrial liver fraction (s-9). this activation is nadph-independent and non microsomal. it is caused by a factor in the soluble fraction (115 000 g supernatan ... | 1978 | 24503 |
| biotransformation and bioactivation of 7,12-dimethylbenzaanthracene in human fetal and placental tissues. analyses of hplc profiles and studies with salmonella typhimurium. | | 1978 | 26548 |
| salmonella typhimurium peptidase active on carnosine. | wild-type salmonella typhimurium can use carnosine (beta-alanyl-l-histidine) as a source of histidine, but carnosine utilization is blocked in particular mutants defective in the constitutive enzyme peptidase d, the product of the pepd gene. biochemical evidence for assigning carnosinase activity to peptidase d (a broad-specificity dipeptidase) includes: (i) coelution of carnosinase and dipeptidase activity from diethylaminoethyl-cellulose and bio-gel p-300 columns; (ii) coelectrophoresis of car ... | 1978 | 26655 |
| mutations that alter the covalent modification of glutamine synthetase in salmonella typhimurium. | glnd and glne mutant strains of salmonella typhimurium lack three of the four activities required for reversible covalent modification of glutamine synthetase (gs; ec 6.3.1.2). the glnd strains, which are unable to deadenylylate gs and therefore accumulate the adenylylated or less active form of the enzyme, were isolated as glutamine bradytrophs. they lack the activity of piia uridylyl-transferase, one of the proteins required for deadenylylation of gs; in addition, they lack piid uridylyl-remov ... | 1978 | 26663 |
| on the evolution of an oligocephalic enzyme. glutamine-chorismate-amidotransferase-free anthranilate phosphoribosyltransferases from mutant strains of salmonella typhimurium. | (1) a procedure has been described for the purification of two glutamine-chorismate-amidotransferase-free anthranilate phosphoribosyltransferases from mutant strains tax6trpr782 and trpab1653trpr782 of salmonella typhimurium. (2) the native enzymes tend to aggregate forming polymers of molecular weights 333,000 in the case of taxtrpr782 and 220,000 and larger than 1x10(6) in the case of trpab1653trpr782. in the presence of sodium dodecyl sulfate the polymer of trpab1653trpr782 dissociates into a ... | 1978 | 27022 |
| differential mutagenicity of reaction products of various pyrazolones with nitrite. | four pyrazolones in frequent use, i.e. antipyrine (ap), aminopyrine (amp), sulpyrine (sp) and isopropylantipyrine (ipa), were compared for their reactivity with nitrite and for the in vitro mutagenicity of their reaction products by ames' reversion tests. in various acidic solutions at 37 degrees c, ap, amp and sp were found to react easily with nitrite and yield various products including dimethylnitrosamine (dmna) and 4-nitrosoantipyrine (4-nap) in the cases of amp and ap, respectively. when t ... | 1978 | 27721 |
| utilization of d-amino acids by dadr mutants of salmonella typhimurium. | utilization of d-amino acids being substrates of d-amino acid dehydrogenase of salmonella typhimurium was examined. the experiments were done with wild type strains and the mutants dada missing the enzyme activity and dadr in which its synthesis is released from catabolite repression. growth on d-tryptophan, d-histidine and d-methionine used as precursors of the l-amino acids was faster when the respective auxotrophs carried dadr mutations. the dadr mutants grew faster when d-or l-alanine was pr ... | 1978 | 29590 |
| effects of surface-active agents on neutrophil receptors. | an easily performed assay to identify the c3b and fc receptors on human neutrophils was developed. salmonella typhimurium were treated with fluorescein and then incubated in nonimmune fresh human serum, which led to c3b fixation via activation of the alternative pathway. similarly, type ii pneumococci were treated with fluorescein and opsonized with type-specific rabbit antiserum. neutrophils bearing c3b and fc receptors formed rosettes with the respective bacteria, which were easily readable be ... | 1978 | 30696 |
| protective ability of salmonella ribosomal protein and rna in inbred mice. | ribosomal vaccines prepared from salmonella typhimurium were effective immunogens in a/j, c3h/hedub, and c3h/hej mice. purified ribosomal components were also tested as immunogens in the inbred mice. protein isolated from a salmonella ribosomal fraction could protect all three mouse strains. although purified rna was shown to be protective for a/j and c3h/hedub mice, it was not protective for c3h/hej mice. protective immunity could be induced in a/j and c3h/hedub mice by various immunostimulants ... | 1978 | 30697 |
| salmonella typhimurium lt-2 mutants with altered glutamine synthetase levels and amino acid uptake activities. | to determine whether salmonella typhimurium has a nitrogen control response, we have examined the regulation of nitrogen utilization in two mutants with fivefold and threefold elevations in their glutamine synthetase activities. the mutants do not require glutamine for growth on glucose--ammonia medium but do have altered growth on other nitrogen sources. they grow better than an isogenic control on media containing arginine or asparate, but more slowly with proline or alanine as nitrogen source ... | 1978 | 30754 |
| binding of cholesterol by neisseria gonorrhoeae. | the binding of [1,2-3h]cholesterol to neisseria gonorrhoeae cs-7, pseudomonas aeruginosa, and salmonella typhimurium (smooth and rough strains) was investigated. the kinetics of cholesterol binding to n. gonorrhoeae cs-7 demonstrated that binding occurred slowly with maximum binding by 10 h. under optimum conditions, a large percentage (65%) of the added cholesterol was associated with the cells. chemical fractionation revealed that ca. 98% of the labeled cholesterol was associated with the cell ... | 1978 | 32139 |
| serum opsonic deficiency produced by streptococcus pneumoniae and by capsular polysaccharide antigens. | the opsonic requirements for phagocytosis of s. pneumoniae types 6, 7, 18, and 23 were determined in normal and c2 deficient serum, and in normal serum chelated with magnesium ethyleneglycoltetraacetic acid. all four strains were effectively opsonized via the alternative complement pathway, a finding suggesting that the capsular polysaccharides of these strains activated complement via the alternative pathway. since bacteremic pneumococcal disease is often associated with circulating capsular po ... | 1978 | 34937 |
| mutagenicity of the non-carcinogenic dibenzylnitrosamine and an alpha-acetoxy derivative. | the mutagenicity of a non-carcinogenic nitrosamine, n,n-dibenzylnitrosamine (i), and a chemically synthesized alpha-acetoxy derivative, n-(alpha-acetoxy-benzyl)-n-benzylnitrosamine (ii), has been examined in salmonella typhimurium ta100 and ta1535. compound (i) was non-mutagenic when tested directly or in the presence of a metabolic activation system while (ii) was highly mutagenic when tested directly. this is the first report on the conversion of a non-mutagenic n-nitrosamine to a mutagen by t ... | 1979 | 35280 |
| nitrogen control of salmonella typhimurium: co-regulation of synthesis of glutamine synthetase and amino acid transport systems. | nitrogen control in salmonella typhimurium is not limited to glutamine synthetase but affects, in addition, transport systems for histidine, glutamine, lysine-arginine-ornithine, and glutamate-aspartate. synthesis of both glutamine synthetase and transport proteins is elevated by limitation of nitrogen in the growth medium or as a result of nitrogen (n)-regulatory mutations. increases in the amounts of these proteins were demonstrated by direct measurements of their activities, by immunological ... | 1979 | 35521 |
| method for salmonella concentration from water at ph 3.5, using micro-fiber glass filters. | a method is described for the concentration of salmonella from water. as is done with enterovirus, salmonella bacteria were concentrated from water in two steps: by ph 3.5 adsorption on and ph 9.5 elution from 8-micron porosity micro-fiber glass filter tubes. this method worked in less than 30 min, and salmonella typhimurium was inactivated only slightly in spite of rapid ph variations (ph 3.5 to 9.5). it was demonstrated that the retention by the filters stems from two phenomena: a low retentio ... | 1979 | 39501 |
| mutagenic activation of tris(2,3-dibromopropyl)phosphate: the role of microsomal oxidative metabolism. | the flame retardant tris(2,3-dibromopropyl)phosphate (tris-bp) is converted to products which are mutagenic for salmonella typhimurium ta 100 in the presence of rat liver microsomes, nadph and oxygen. other bromopropyl-compounds were also mutagenic; 2,3-dibromopropene and 2,3-dibromopropionic acid were directly mutagenic, whereas 2,3-dibromopropanol and tris(2-bromopropyl)phosphate were weakly mutagenic after addition of liver microsomes and cofactors. typical in vivo and in vitro inhibitors of ... | 1979 | 40390 |
| the inhibitory effect of bovine rumen fluid on salmonella typhimurium. | the possible fate of salmonella typhimurium in the rumen was investigated by monitoring rumen volatile fatty acids (vfa), lactate concentrations and ph over periods which included regular feeding and 48 h starvation. preparations were made containing 50 per cent rumen fluid from the cow or vfa solutions, and then inoculated with s typhimurium. viable counts before and after incubation for 24 h at 37 degrees c were compared. incubation in broths with high concentrations of vfa and low ph resulted ... | 1979 | 42125 |
| [compared survival of "escherichia coli" and "salmonella typhi-murium" in cold water (author's transl)]. | the survival rates of escherichia coli and salmonella typhi-murium in water are studied at 4, 10 and 20 degrees c and ph 6 and 8, either separately or in mixed culture at four different ratios. s. typhi-murium's survival rate is enhanced at ph 6 and low water temperature. the value of traditional microbiological indicators in assessed in cold water conditions. | 1979 | 43688 |
| elucidation of the inhibitory factors of yogurt against salmonella typhimurium. | the inhibitory nature of yogurt against contaminating microorganisms has been studied extensively. nevertheless, the factors responsible for the death of salmonella typhimurium in yogurt have not been elucidated. an understanding of these factors is important for the determination of yogurt's safety to consumer health. yogurt fermented for 18 h at 42 c had a stable environment with the following conditions: ph 3.85, oxidation-reduction potential -80 mv, lactic acid concentration 158 mm, and acet ... | 1979 | 44306 |
| [investigations on the fatty acid composition of lipids from salmonella typhimurium s and r forms (author's transl)]. | | 1979 | 44942 |
| mutagenicities of smoke condensates and the charred surface of fish and meat. | smoke condensates obtained from broiling fish showed mutagenic activity for salmonella typhimurium ta100 and ta98. metabolic activation was required to induce mutagenic activity of smoke condensates of some species of fish. the smoke condensate obtained during charcoal broiling of beefsteak was far less mutagenic than that of fish, with or without metabolic activation. extracts of the charred surface of broiled fish and meat also contained mutagenic substances. these extracts needed metabolic ac ... | 1977 | 45723 |
| salmonella typhimurium resistant to silver nitrate, chloramphenicol, and ampicillin. | a strain of salmonella typhimurium appeared sequentially in three patients in a burn unit, and epidemiological study suggested the occurrence of person-to-person spread. this organism was responsible for both colonisation and invasive infection in these patients whose burn surfaces were receiving topical treatment with 0.5% silver nitrate (agno3) solution. the antibiotic and metal ionsusceptibility pattern of this strain of s. typhimurium was unique and disturbing: resistant to silver nitrate, m ... | 1975 | 46385 |
| person-to-person spread of salmonella typhimurium after a hospital common-source outbreak. | in september, 1973, diarrhoea caused by salmonella typhimurium developed in 32 people in a maine hospital. both epidemiological and microbiological evidence indicated that raw egg beaten in milk ("egg-nog") was responsible for the infection. however, 6 patients and 8 employees had not had egg-nog, and their illness developed after the source of infection had been recognised and removed. most of these people had had direct contact with an infected patient, and presumably acquired the infection ... | 1975 | 46457 |
| stimulation of phagocytic activity in the reticuloendothelial systems of mice by lipid a complexed with homologous or heterologous proteins. | heterologous proteins are more suitable carriers than homologous proteins for the expression of endotoxic activity of lipid a prepared from the lipopolysaccharides of salmonella typhimurium sl1102 (re form) to stimulate the reticuloendothelial system of mice. | 1975 | 46844 |
| letter: person-to-person spread of salmonella typhimurium. | | 1975 | 47981 |
| salmonella typhimurium mutations conferring resistance to felix o phage without loss of smooth character: phage attachment and immunochemical and structural analyses of lipopolysaccharides. | salmonella typhimurium mutants, called felix o-resistant (for), selected for resistance to phage felix o (fo) which has its receptor in the core lipopolysaccharide (lps), retain most of the properties of the smooth parent strain (macphee, krishnapillai, roantree & stocker, 1975). lps extracted from one parent and two for strains by the phenol-water and the phenol-chloroform-light petroleum methods have been subjected to passive haemagglutination inhibition and methylation analysis. the amount of ... | 1975 | 48537 |
| immunological study of anthranilate synthetase. | an immunological study of anthranilate synthetase (asase) has been initiated using quantitative precipitation, enzyme neutralization, and immunodiffusion methods. cross-reactivity of anthranilate synthetase-anthranilate-5-phosphoribosylpyrophosphate phosphoribosyltransferase (asase-prtase) from escherichia coli, klebsiella aerogenes, and salmonella typhimurium and asase from serratia marcescens and pseudomonas putida was detected with antibodies to ?e. coli trypsin-treated asase. cross-reactivit ... | 1975 | 50316 |
| shared antigens between bacteria and guinea pig line 10 hepatocarcinoma cells. | this study was undertaken to investigate the possibility that listeria monocytogenes, brucella abortus, and salmonella typhimurium share antigenic components with guinea pig line 10 hepatocarcinoma cells. rabbits were immunized with sonicates of these bacteria or line 10 tumor cells. other rabbits were immunized with line 1 cells, a tumor with antigenic characteristics different from those of line 10. the binding of antibodies to radiolabeled antigens prepared from extracts of bacteria and line ... | 1976 | 57823 |
| extension of host-range for coliphage bf23 to include salmonella typhimurium. | | 1975 | 58634 |
| [detection of the membranous structures of salmonella typhimurium at a neutral isoelectric point]. | | 1976 | 63102 |
| structure and properties of a hybrid tryptophan synthetase of alpha chain produced by genetic exchange between escherichia coli and salmonella typhimurium. | genetic exchange between the structural genes for the alpha chain of tryptophan synthetase [tryptophan synthase; l-serine hydro-lyase (adding indoleglycerol-phosphate), ec 4.2.1.20] of e. coli and s. typhimurium yielded recombinant genes that specified functional hybrid polypeptides. the alpha chains produced by three recombinants appeared to be identical but differed from those of e. coli and s. typhimurium by at least 27 and 8 amino acid residues, respectively. in vivo and in vitro tests of en ... | 1977 | 64983 |
| neutralization of salmonella toxin-induced elongation of chinese hamster ovary cells by cholera antitoxin. | a partially purified preparation of the delayed skin permeability factor from salmonella typhimurium caused chinese hamster ovary cells to elongate. the elongation effect and the skin test activity were blocked by monospecific rabbit antisera against cholera toxin and against the b fragment of cholera toxin, | 1977 | 67084 |
| effectiveness of parenteral and oral typhoid vaccination in mice challenged with a salmonella typhi-salmonella typhimurium hybrid. | live salmonella typhi administered intraperitoneally, acetone-killed s. typhi administered intraperitoneally, and live s. typhi given orally, with their effectiveness decreasing in that order, protected swiss white mice against death from challenge with a virulent salmonella typhimurium hybrid expressing s. typhi antigens. | 1977 | 67085 |
| mutants of coliphage bf23 able to propagate on smooth strains of salmonella typhimurium. | | 1976 | 71066 |
| heterospecific transduction as a tool to select dna processing mutations in salmonella typhimurium [proceedings]. | | 1977 | 79345 |
| ingested mutagens from opium and tobacco pyrolysis products and cancer of the oesophagus. | substances which are commonly sucked or chewed in two areas where the incidence of oesophageal cancer is high, the transkei and north-east iran, were tested in bacterial mutagenicity assays. pyrolysed substances, opium dross in north-east iran and tobacco pipe residues in the transkei, displayed mutagenic activity in salmonella typhimurium strains ta98 and ta100 in the presence of rat liver microsomes. | 1978 | 79865 |
| direct-acting mutagens in automobile exhaust. | particulate matter in city air contains chemicals which are mutagenic in the ames salmonella typhimurium assay. in residential urban areas, the principal mutagens in air do not require liver enzymes to be activated. the source of these liver independent (direct-acting) mutagens may be automobile exhaust because (1) the mutagenic activities were correlated to the lead content or air, (2) the mutagens were found exhaust samples from automobiles and from an experimental cfr single-cylinder gasoline ... | 1978 | 80258 |
| treatment of salmonella typhimurium salmonellosis. | | 1978 | 80570 |
| masking of protein antigen by modification of amino groups with carbobenzoxychloride (benzyl chloroformate) and demasking by treatment with nonspecific protease. | cryostat sections of various substrates were treated with carbobenzoxychloride in acetone to modify antigens. by applying specific fluorescent antibodies, it could be shown that the antigenic determinants of rabbit gamma-globulin and bovine insulin were totally masked. the antigenicity of acth was markedly reduced, whereas the polysaccharide antigens of salmonella typhimurium were only partially masked. after masking, antigenicity could be restored by treatment with nonspecific protease. the rev ... | 1978 | 82572 |
| [safety evaluation of nk 631. antigenicity, effect on delated hypersensitivity, irritative effect on eye mucous membrane and mutangenicity of pepleomycin (nk 631) (author's transl)]. | 1. whether nk 631 is antigenic to guinea pigs and rabbits was studied by the methods of active and passive anaphylactic shock tests, schultz-dale reaction, passive cutaneous anaphylaxis, ouchterlony, tanned red cell haemagglutination test and test according to the u.s. appraisal of the safety of chemicals in foods, drugs and cosmetics. however, none of the tests proved nk 631 to be antigenic. 2. the immunosuppressive effect of nk 631 was studied by delayed hypersensitivity to picryl chloride in ... | 1978 | 83409 |
| an alteration in outer membrane permeability associated with a division lesion in a strain of salmonella typhimurium. | salmonella typhimurium strain 4a is a temperature sensitive mutant with defects in both septation and separation. the separation lesion was reversed by phenethylalcohol but this agent failed to allow septation or growth at restrictive temperature. organisms of strain 4a grown at 42 degrees c were, unlike the parental strain, resistant to lysis by lysozyme plus edta and lipopolysaccharide was poorly extracted by edta from cultures of strain 4a grown at 42 degrees c. such cultures may, therefore, ... | 1978 | 83740 |
| binding properties of goat igm anti-dinitrophenyl antibodies. | goats immunized over 2 months with low doses of 1 mg/kg of dinitrophenylated salmonella typhimurium responded with low levels of anti-dnp antibodies restricted to the igm class. the purified antibodies show low association constants (ka between 10(4) of 10(5) l/m), a high degree of homogeneity (heterogeneity indices alpha between 0.7 and 0.9) and ten combining sites when tested against dinitrophenyl-lysine as ligand by equilibrium dialysis. these binding properties remained unchanged during the ... | 1978 | 86504 |
| effect of subminimal inhibitory concentrations of mecillinam on the synthesis of dna, rna, and protein of salmonella typhimurium: a proposed mechanism of action. | salmonellae alter their rod-like morphology to become large ovals within 3-5 hr after being exposed to concentrations of mecillinam below the minimal inhibitory concentration. before this overt morphologic change occurs, synthesis of dna increases, with a concomitant decrease in total protein synthesis. incorporation of [3h]leucine into cell wall protein is markedly inhibited by mecillinam, whereas incorporation of leucine into soluble intracellular proteins is enchanced by the drug. electrophor ... | 1979 | 94451 |
| [protective action on mice of acellular extracts from salmonella typhimurium]. | acellular fractions obtained by saline extraction at 60 or at 100 degree c of salmonella typhimurium protect mice against an experimental infection with the homologous strain. after purification, these fractions which are complex, might be used for the development of a vaccine. | 1978 | 97021 |
| listeria monocytogenes cell walls induce decreased resistance to infection. | a significant decrease in murine resistance to listeria monocytogenes was induced by using crude listeria cell wall fraction (lcwf) and purified listeria cell walls (pf). when equal amounts of these materials were injected, pf was more effective than lcwf in decreasing resistance. the pf effect was dose dependent when measured either as a decrease in 50% lethal dose of the listeria challenge or as a decrease in survival time of the infected mice. pf apparently does not act directly on the lister ... | 1978 | 97226 |
| ultrastructural study of salmonella typhimurium treated with membrane-active agents: specific reaction dansylchloride with cell envelope components. | amino groups of cell envelope proteins, lipids, and lipopolysaccharides cannot be labeled in intact cells of salmonella typhimurium g 30 by using 5-dimethylaminonaphthalene-1-sulfonylchloride incorporated in lecithin-cholesterol vesicles. however, application of membrane-interacting agents like tris(hydroxymethyl)aminomethane (tris)-hydrochloride, ethylenediaminetetraacetate (na salt) (edta), divalent cations, and sublethal doses of the cationic antibacterial agents polymyxin b and chlorhexidine ... | 1978 | 97268 |
| isolation of large bacterial plasmids and characterization of the p2 incompatibility group plasmids pmg1 and pmg5. | large plasmids from agrobacterium tumefaciens, salmonella typhimurium, escherichia coli, pseudomonas putida, and pseudomonas aeruginosa were routinely and consistently isolated using a procedure which does not require ultracentrifugation but includes steps designed to separate large-plasmid dna from the bacterial folded chromosome. it also selectively removes fragments of broken chromosome. a variety of large plasmids was readily visualized with agarose gel electorphoresis, including five betwee ... | 1978 | 97269 |
| antibacterial functions of macrophages in experimental protein-calorie malnutrition. ii. cellular and humoral factors for chemotaxis, phagocytosis, and intracellular bactericidal activity. | cellular and humoral aspects of the antibacterial activity of macrophages during experimental protein-calorie malnutrition were studied. there were no defects in chemotaxis or bactericidal activity of cells from protein-deficient animals, although phagocytosis-associated oxygen consumption and hexose monophosphate shunt activity were depressed. however, marked impairment of humoral chemotactic factors generated in the peritoneal cavity by glycogen injection and of heatlabile serum opsonins for s ... | 1978 | 98599 |
| model for disseminated intravascular coagulation: bacterial sepsis in rhesus monkeys. | dic is a hemorrhagic syndrome frequently encountered as a complication in severe gram-negative bacterial sepsis. an animal model for sepsis-associated dic was developed in order to permit study of the appearance and development of this syndrome in relation to the entire disease process. rhesus monkeys (4 to 6 kg) were infected by intravenous injection of 10(9) salmonella typhimurium organisms and studied for a period of 7 to 10 days following infection. ten of 23 infected monkeys developed petec ... | 1978 | 98603 |
| tissue-mediated mutagenicity of vinylidene chloride in salmonella typhimurium ta1535. | vinylidene chloride is weakly positive in the salmonella typhimurium ta1535 test, mediated by kidney and liver post-mitochondrial supernatant (s-9 mix) from normal mice, but strongly positive with the s-9 mix from the induced animals. in the case of mediation by rat tissue, only liver s-9 mix from induced animals affords a significant positive response. these findings agree with the greater availability in treated mice than in rats of reactive vinylidene chloride metabolites, 1,1-dichloroethylen ... | 1978 | 99228 |
| purine nucleoside phosphorylase from salmonella typhimurium and rat liver. | | 1978 | 99637 |
| strain-dependent cytotoxic effects of endotoxin for mouse peritoneal macrophages. | the cytotoxic effects of bacterial lipopolysaccharides (lps) on mouse leukocytes have been examined in vivo and in vitro. intraperitoneal injection of lps into c57bl/6 mice greatly reduced the recovery of mononuclear cells; lps was cytotoxic for macrophages, but had a mitogenic effect on lymphocytes. similar effects of lps on peritoneal leukocytes were observed in vitro. when monolayers of adherent peritoneal cells were studied in vitro, cytotoxicity was also observed, suggesting that the effect ... | 1978 | 101460 |
| heat-labile b-cell mitogen obtained from listeria monocytogenes. | a water-soluble extract of listeria monocytogenes strain 10403 acts as a mitogen on cultured mouse spleen lymphocytes. this mitogen induced a response six to nine times that of controls, as measured by [3h]thymidine incorporation. the mitogen extract was derived from washed bacterial cells which were mechanically disrupted with a french press. the extract was centrifuged at 105,000 x g and filtered through a 0.22-micrometer filter. similar levels of lymphocyte stimulation were observed in lympho ... | 1978 | 103837 |
| homology of the gene coding for outer membrane lipoprotein within various gram-negative bacteria. | the mrna for a major outer membrane lipoprotein from escherichia coli was found to hybridize specifically with one of the ecori and one of the hindiii restriction endonuclease-generated fragments of total dna from nine bacteria in the family enterobacteriaceae: e. coli, shigella dysenteriae, salmonella typhimurium, citrobacter freundii, klebsiella aerogenes, enterobacter aerogenes, edwardsiella tarda, serratia marcescens, and erwinia amylovora. however, among the enterobacteriaceae, dna from two ... | 1979 | 104972 |
| mutagenic effect of 7, 12-dimethylbenz[a]anthracene-epidioxide on salmonella typhimurium. | | 1979 | 106234 |
| mutagenicity of 4-nitropyridine-1-oxide for salmonella typhimurium. | | 1978 | 106271 |
| mutagenicity studies with x-ray-contrast media, analgesics, antipyretics, antirheumatics and some other pharmaceutical drugs in bacterial, drosophila and mammalian test systems. | as part of our investigation into mutagenic effects of environmental compounds, we studied 21 pharmaceuticals most frequently sold in west germany: 6 x-ray-contrast media, 13 analgesics, antipyretics and antirheumatics, 1 central stimulant, and 1 antidepressant. they were studied in different bacterial, drosophila and mammalian test systems. 4 of these 21 compounds could be detected as mutagens in one of the test systems. namely: 1,2-dichloroethane induced an increase in the frequency of recessi ... | 1979 | 106272 |
| comparison of the in vitro mutagenicity and metabolism of dimethylnitrosamine and benzo[a]pyrene in tissues from inbred mice treated with phenobarbital, 3-methylcholanthrene or polychlorinated biphenyls. | homogenates of liver, lung, kidney, stomach, small intestine and colon from 8 strains of mice were compared for their ability to metabolize benzo[a]pyrene (bp) and dimethylnitrosamine (dmn) to mutagens. females of strains cf1, akr/j, au/ssj, dba/2j, swr/j, a/j, c3h/hej, and c57bl/6j were either untreated or received phenobarbital (pb), 3-methylcholanthrene (mc) or polychlorinated biphenyls (ar) to induce drug-metabolizing enzymes. the effects of these drugs on organ weight and on the amounts of ... | 1979 | 106274 |
| conversion of 2,4,6-trinitrophenol to a mutagen by pseudomonas aeruginosa. | a strain of pseudomonas aeruginosa reduced 2,4,6-trinitrophenol (picric acid) to 2-amino-4,6-dinitrophenol (picramic acid) under anaerobic conditions. mutagenic assays of picric acid and picramic acid were carried out with histidine-requiring strains of salmonella typhimurium. picric acid (10 micrograms per plate) demonstrated mutagenicity (both frame shift and base substitution-gype mutations) only after activation with a rat liver homogenate preparation. picramic acid (1 microgram per plate) i ... | 1979 | 107854 |
| isolation and characterization of bacterial flagellar hook proteins from salmonellae and escherichia coli. | flagellar hook proteins from salmonella and escherichia coli were dissociated in acid and purified by diethylamino-ethyl-cellulose column chromatography. these two proteins had the same electrophoretic mobility in sodium dodecyl sulfate-polyacrylamide gels. however, analytical electrofocusing patterns showed that these proteins had different isoelectric points (4.7 for salmonella typhimurium and 4.4 for e. coli). immunodiffusion and immuno-electron microscopy carried out with antisera prepared a ... | 1979 | 108251 |
| comparative mutagenicity of palmotoxin bo and aflatoxins b1 and m1. | the mutagenicity of palmotoxin bo and of aflatoxin m1 relative to that of aflatoxin b1, the potent mutagen, was studied in five ames' tester strains of salmonella typhimurium (ta-98, ta-100, ta-1535, ta-1537, ta-1538). aflatoxins b1 and m1 are both highly mutagenic in a microsome-mediated system in ta-100. the prediction of the relative carcinogenicity of aflatoxin m1 to aflatoxin b1 posed by the mutation of ta-100 is probably more authentic than ta-87. the mutagenic potency of palmotoxin bo is ... | 1979 | 109559 |
| positive control of lac operon expression in vitro by guanosine 5'-diphosphate 3'-diphosphate. | maximal expression of the escherichia coli lactose operon in a coupled in vitro transcription-translation system from a salmonella typhimurium rela mutant was strongly dependent upon addition of guanosine 5'-diphosphate 3'-diphosphate (ppgpp). without added ppgpp, at saturating 3',5'-cyclic amp (camp) concentrations, synthesis of beta-galactosidase (beta-d-galactoside galactohydrolase, ec 3.2.1.23) was reproducibly only 5-7% of that which can be obtained with 0.5-0.8 mm ppgpp. experiments in whi ... | 1979 | 109832 |
| aminopeptidase i activities in several microorganisms. | aminopeptidase i activity which was found to be localized in the same subcellular fraction and to be similarly heat stable was partially purified by a common procedure from escherichia coli b, escherichia coli k12, enterobacter aerogenes, salmonella typhimurium, serratia marcescens pseudomonas aeruginosa, and proteus vulgaris. the enzyme preparations were shown to contain a single animopeptidase active toward both leucylleucine and methionylalanylserine by mixed-substrate initial-velocity kineti ... | 1978 | 110425 |
| susceptibility of cba/n mice to infection with salmonella typhimurium: influence of the x-linked gene controlling b lymphocyte function. | | 1979 | 110879 |