Publications

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
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
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
proton efflux associated with melibiose permease activity in salmonella typhimurium.		1978	27177
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
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
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
biotransformation and bioactivation of 7,12-dimethylbenzaanthracene in human fetal and placental tissues. analyses of hplc profiles and studies with salmonella typhimurium.		1978	26548
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
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
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
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
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
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
glutamine synthetase from salmonella typhimurium: manganese(ii), substrate, and inhibitor interaction with the unadenylylated enzyme.		1977	20051
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
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
characterization of an endonuclease associated with the drug resistance plasmid pkm101.	an endonuclease was detected in strains of salmonella typhimurium containing the drug resistance plasmid pkm101. the enzyme was not detectable in strains lacking this plasmid, but it was present in strains containing mutants of pkm101 that were no longer able to enhance host cell mutagenesis. the endonuclease had a molecular weight of roughly 75,000 and, at ph 7.0, was equally active on single-stranded and duplex deoxyribonucleic acid (dna). the reaction with single-stranded dna was optimal at p ...	1977	18440
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
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
lipid a mutants of salmonella typhimurium. purification and characterization of a lipid a precursor produced by a mutant in 3-deoxy-d-mannooctulosonate-8-phosphate synthetase.	we describe here the isolation, purification, and structural characterization of a lipid a precursor synthesized under nonpermissive conditions by a mutant of salmonella typhimurium conditionally defective in the synthesis of the 3-deoxy-d-mannoctulosonate (2-keto-3-deoxyoctonate, kdo) region of the lipopolysaccharide. the precursor was isolated free from lipopolysaccharide, murein, and phospholipids by extraction of delipidated cells with 90% phenol/chcl3/petroleum ether. the molecule was recov ...	1977	17608
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
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
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
sodium-dependent methyl 1-thio-beta-d-galactopyranoside transport in membrane vesicles isolated from salmonella typhimurium.	membrane vesicles isolated from salmonella typhimurium g-30 grown in the presence of melibiose catalyze methyl 1-thio-beta-d-galactopyranoside (tmg) transport in the presence of sodium or lithium, as shown initially with intact cells by stock and roseman (stock, j., and roseman, s. (1971), biochem. biophys. res. commun. 44, 132). tmg-dependent sodium uptake is also observed, but only when a potassium diffusion potential (interior negative) is induced across the vesicle membrane. cation-dependent ...	1977	16639
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
lack of a regulatory function for glutamine synthetase protein in the synthesis of glutamate dehydrogenase and nitrite reductase in escherichia coli k12.	synthesis of glutamine synthetase (gs) in anaerobic batch cultures of escherichia coli was repressed when excess nh4+ was available, but derepressed during growth with a poor nitrogen source. in wild-type bacteria there was only a weak inverse correlation between the activities of gs and glutamate dehydrogenase (gdh) during growth in various media. no positive correlations were found between the activities of gs and nitrite reductase, or between gs and cytochrome c552: both of these proteins wer ...	1977	16079
properties of two phosphatases and a cyclic phosphodiesterase of salmonella typhimurium.	the properties of three phosphatases from salmonella typhimurium have been examined. a cyclic 2',3'-nucleotide phosphodiesterase (ec 3.1.4.d) hydrolyzes cyclic 2',3'-purine and -pyrimidine nucleotides, as well as 3'-mononucleotides, and has a ph optimum of about 7.5. it requires divalent cations for activity and has a molecular weight of 67,000. acid hexose phosphatase (ec 3.1.2.2) possesses activity towards hexose phosphates as well as other sugar phosphates. the enzyme is apparently a dimer of ...	1977	15982
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 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
ornithine transcarbamylase from salmonella typhimurium: purification, subunit composition, kinetic analysis, and immunological cross-reactivity.	ornithine transcarbamylase (otcase) was purified to hemogeneity from a derepressed strain of salmonella typhimurium. the optimal ph for enzyme activity is 8.0. the molecular weight of the enzyme was calculated to be 116,000, based on measurements of the sedimentation coefficient by sucrose gradient ultracentrifugation and the stokes radius by gel filtration. polyacrylamide gel electrophoresis of cross-linked otcase in the presence of sodium dodecyl sulfate showed that the enzyme is composed of t ...	1977	14923
proton movements coupled to sugar transport via the galactose transport system in salmonella typhimurium.	we have studied proton movements associated with substrate transport via the galactose transport system in salmonella typhimurium. the addition of galactose to lightly buffered suspensions of anaerobic, non-metabolizing cells of salmonella typhimurium, specifically induced for the galactose transport system, causes an increase in extracellularph as galactose and protons enter the cell together. other substrates for this transport system, d-fucose, 2-deoxygalactose, glucose and 2-deoxyglucose sim ...	1977	14832
adsorption of phage p22 to salmonella typhimurium.	adsorption of phage p22 to its receptor in the lipopolysaccharide (lps) of the envelope of salmonella typhimurium is accompanied by a hydrolytic cleavage of the o polysaccharide chain. the enzyme, and endorhamnosidase, is found in the phage tail. propagation of a mutant of phage p22, containing two amber mutations, under restrictive conditions permitted isolation of phage tail parts with endorhamnosidase activity. the tail parts, purified by ion exchange chromatography, were shown to be homogeno ...	1977	14224
repression of the tyrosine, lysine, and methionine biosynthetic pathways in a hist mutant of salmonella typhimurium.	a comparison was made of the repressibility of certain enzymes in the tyrosine, methionine, and lysine biosynthetic pathways in wild-type salmonella typhimurium and a hist mutant. the results show that (i) tyrosine represses the synthesis of the tyrosine-sensitive 3-deoxy-d-arabino-heptulsonic acid 7-phosphate synthetase and the tyrosine aminotransferase to the same extent in a hist mutant as in wild type and (ii) there is no detectable alteration in the extent to which methionine represses o-su ...	1977	14106
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
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
mutant strains (nit) of salmonella typhimurium with a pleiotropic defect in nitrogen metabolism.	we have isolated mutant strains (nit) of salmonella typhimurium that are defective in nitrogen metabolism. they have a reduced ability to use a variety of compounds including glutamate, proline, arginine, n-acetyl-glucosamine, alanine, and adenosine as sole nitrogen source. in addition, although they grow normally on high concentrations of ammonium chloride (greater than 1 mm) as nitrogen source, they grow substantially more slowly than wild type at low concentrations (less than 1 mm). we postul ...	1976	10275
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
effect of mutagenic metabolic activation of n-nitrosomorpholine on microorganisms.	almost similar sensitivity is demonstrated of different methods of studying mutagenic metabolic activation of n-nitrosomorpholine (nm) in salmonella typhimurium ta 1950 (host-mediated assay and the system of metabolic activation with rat liver homogenate). the role of correlation of certain ingredients of nm metabolic activation system with homogenates (homogenate and cofactor nadph concentrations) is studied. the fact of influence of microsome protein activator (phenobarbital) on the nm mutagen ...	1976	10229
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
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
rat and mouse tissue-mediated mutagenicity of ring-substituted 3,3-dimethyl-1-phenyltriazenes in salmonella typhimurium.	3,3-dimethyl-1-phenyltriazene and a series of ring-substituted derivatives (x-phi-n=n-n-(ch3)2:x=substituent(s); phi=phenyl) were tested for their mutagenic and toxic action upon salmonella typhimurium g-46 in a liquid incubation system containing 9000 g tissue supernatants and an nadph-generating system. the compounds could be grouped into four classes according to their toxicity and mutagenicity after 1 h incubation at 37 degrees c at a concentration of 5 mm in the presence of liver supernatan ...	1976	7749
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
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
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
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
vinyl chloride dependent mutagensis: effects of liver extracts and free radicals.	the mutagenic effects of vinyl chloride (vc) on salmonella typhimurium strain ta1530 are enhanced by mouse or rat liver extracts. the extracts prepared from mice pretreated either with vinyl chloride or the microsomal enzyme inducer, aroclor 1254, did not produce any greater stimulation of vc-dependent mutagenesis than extracts from untreated animals. these same extracts, however, differed markedly in their capacity to stimulate the mutagenicity of dimethylnitrosamine (dmn), a compound which is ...	1976	5669
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
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
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
changes in bile physicochemical indexes in experimental salmonella typhimurium carrier state.		1975	3718
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
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
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
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
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
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
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