| 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 |
| past and present aspects of diarrheal disease in childhood. clinical study and treatment (author's transl). | the etiologic and pathophysiologic findings described in the first part of this paper have important consequences: the recognition of the specific etiology of diarrhea requires new laboratory methods: most of these, however, are technically easy to perform and do not require a large laboratory. a long-ranging consequence of this changed concept is a well-founded modification of therapy. the most important discovery was, that in a well balanced glucose electrolyte solution sodium and glucose enha ... | 1975 | 1346 |
| use of lincomycin, methicillin and ristomycin in the nutrient media for isolating pathogenic intestinal microorganisms. | elective-differentiating solid nutrient media for simultaneous isolation of vibrioes, salmonella and shigella were developed. antibiotics active against grampostive microflora and dry bile salts inhibiting the growth of proteus were used as the inhibitors of the growth of the accompanying microflora. the medium was lincomycin and the bile salts may be prepared in a dry form. | 1975 | 2096 |
| proceedings: preliminary investigations on the mode of action of the cocarcinogen a1 using bacteria. | | 1975 | 2726 |
| bacteriological studies on cefatrizine (s-640 p) (author's transl). | | 1976 | 4635 |
| in vitro and in vivo antibacterial activity, blood and urinary levels of a new chemotherapeutic agent similar to nalidixic acid. | | 1975 | 5970 |
| kinetics of haemopoietic recovery in endotoxin-treated mice. | kinetics of mouse spleen colony forming units were studied after intra-peritoneal injection of 1 mug/blody weight bacterial endotoxin s. typhosa. when these mice were used as unirradiated and sublethally irradiated donors, it was possible to study the effect of the endotoxin injection upon the cells. use of the treated mice as irradiated recipients of normal cells gave information about the host effect. in treated unirradiated mice, the total nucleated cell and the cfu counts were disturbed, and ... | 1976 | 4225 |
| changes in bile physicochemical indexes in experimental salmonella typhimurium carrier state. | | 1975 | 3718 |
| 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 |
| 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 |
| classical and postclassical modes of regulation of the synthesis of degradative bacterial enzymes. | | 1976 | 6998 |
| 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 |
| a new method using p-benzoquinone for coupling antigens and antibodies to marker substances. | a method using p-benzoquinone for coupling antigens and antibodies to enzymes and erythrocytes is described. the method involves the treatment of proteins (or polysaccharides) at ph 6 or 7 with an excess of p-benzoquinone. after removal of the unreacted reagent by gel filtration, the "activated" proteins were coupled at ph 8-9 with enzymes or erythrocytes. biological activities of the proteins were not substantially modified by this treatment since 80-100% of the antigen binding capacity was fou ... | 1976 | 7179 |
| bacteriological and physicochemical studies of the meat from poultry with acute marek's disease. | studied were bacteriologically a total of 114 birds affected with acute marek's disease (40 broilers, 44 growing layers, and 30 adult layers) as well as 100 healthy control birds of the same three categories. a chemical analysis was performed of the red and white meat of 20 of the diseased pullets and 20 of the diseased adult layers as well as of 34 of the affected broilers. the investigation included the same numbers of the control birds. extractions of the sampled meat were studied in terms of ... | 1975 | 3015 |
| 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 |
| characteristics of lipopolysaccharides of salmonella typhi isolated from carriers and patients suffering from typhoid fever. | lipopolysaccharides (lps) of salmonella typhi strains, isolated from carriers and patients suffering from typhoid fever, were characterised according to their biochemical properties, morphological structure and degree of aggregation of complexes. all preparations of lps, regardless of their origin, were morphologically heterogeneous. free electrophoresis and immunoelectrophoresis demonstrated that lps preparations were composed of components possessing different mobilities in electric fields. lp ... | 1976 | 2523 |
| effectiveness of the vaccine of vi-antigen of salmonella typhosa in children and adolescents. | | 1975 | 1943 |
| starvation survival of salmonella enteritidis. | washed cells of salmonella enteritidis harvested from a defined medium during logarithmic growth were subjected to starvation in ph 7 phosphate buffer at 37 c. viability was measured by slide cultures and plate counts. the survival of cell suspensions equivalent to 1 to 10 mg (dry wt)/ml was influenced by cryptic growth. the rate of cryptic growth, assessed by plate counts, increased with cell density and could not be alleviated by starvation with dialysis. dialysis of the starving culture did r ... | 1976 | 1369 |
| growth of staphylococcus and salmonella on frankfurters with and without sodium nitrite. | conventional and nitrite-free frankfurters in loosely wrapped packages were compared as to their ability to support growth of salmonella, staphylococcus, and their naturally occurring spoilage flora at 7 c (simulating refrigerated storage) and 20 c (simulating possible temperature abuse). at 7 c salmonella did not grow in either type of frankfurter; staphylococcus and the natural spoilage flora sometimes grew more rapidly in the absence of nitrite, but the difference was not significant. at 20 ... | 1975 | 952 |
| significance of starter cultures for raw sausage aging in view of food and nutrition hygiene. | the authors studied the effects of liquid starter cultures on the survival of pathogenic germs. it was found that the foreign bacteria tested differed in growth limitation which is obviously dependent on acidity and the amount of lactic acid produced by fermentation. since the pathogenic bacteria differ in the ability to survive, it is imperative to observe strict hygienic measures in preparing starter cultures and to use absolutely sterile monocultures for raw sausage ageing. | 1976 | 8718 |
| survival of salmonellae during pepperoni manufacture. | survival of salmonellae in artificially contaminated beef-pork mixtures (approximately 10(4) salmonellae/g) was studied in pepperoni prepared by either a natural flora or lactic starter culture fermentation or in nonfermented sausages. the pepperoni did not become salmonellae free during the usual commercial 15 to 30-day drying period. salmonella dublin was present in all products, fermented or unfermented, after 42 to 43 days of drying. at a lower level of contamination, 10(3)/g, s. dublin coul ... | 1975 | 951 |
| relationship between serum antibiotic concentration and inhibiting potency of the serum. application to ampicillin and amoxicillin. | | 1975 | 654 |
| 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 |
| 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 |
| bacterial meningitis in infancy and childhood in lusaka (one year prospective sturdy). | in approximately 10,000 admissions in a 12 months period, at university teaching hospital, lusaka 85 cases of meningitis were recorded. the signs and symptoms in these patients do not greatly differ from other similar studies in africa. the commonest organism isolated was pneumococcus. there was high mortality rate which was to a large extent due to parents not bringing their children to hospital early enough for medical treatment to be instituted. this is borne out by the fact that 50% of the c ... | 1975 | 5834 |
| microbial interactions in foods: meats, poultry and dairy products. | | 1976 | 5780 |
| 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 |
| serum bactericidal activity in the horseshoe crab, limulus polyphemus. | serum from the horseshoe crab, limulus polyphemus, was examined for bactericidal activity against five species of bacteria. greatest activity was found against pseudomonas putida and flavobacterium sp.; with the former, serum dilutions as high as 1:20 were capable of reducing viable counts by 50% within 2 h. bactericidal activity of a significantly lesser magnitude was demonstrated against serratia marcesencs and salmonella minnesota. no killing was seen when the lobster pathogen aerococcus viri ... | 1976 | 11188 |
| the rotating aeration system fuchs system in the treatment of liquid animal and municipal wastes. 3. hygienic studies on the rotation aeration of cattle slurry. | | 1976 | 5074 |
| the role of aflatoxin metabolism in its toxic lesion. | | 1976 | 4903 |
| 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 |
| 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 |
| classification of acute bacterial meningitis cases according to their etiology, seen in a children's hospital in ankara from march 1973 to april 1974. | in a 14 months period, as from march 1973 to april 1974 468 cases of acute bacterial meningitis have been diagnosed by c.s.f. findings; namely by examining the protein and sugar content, by the cell counts, gram's staining and culturing of the sediments of c.s.f. 188 cases were proven by culturing to be meningococcic meningitis. all these cases are from the families living in suburban areas of the city under crowded circumstances, which show the importance of population density in the epidemiolo ... | 1976 | 6862 |
| 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 |
| immunochemical relationships between bacteria belonging to two separate families: pneumococci and klebsiella. | | 1976 | 3470 |
| observations on brilliant green agar with h2s indicator. | several formulations of brilliant green agar with an added h2s indicator were evaluated. results were optimum with variations of a basic formula consisting of 40 g of tryptic soy agar (difco), 8 g of lactose, 8 g of sucrose, 80 mg of phenol red, 1 g of sulfanilamide, 1.5 g of ferric ammonium citrate, 5 g of sodium thiosulfate pentahydrate, and 7 mg of brilliant green dye per liter. brilliant green dye was added after sterilization of the other components this formulation supported good growth of ... | 1976 | 7190 |
| the effect of lipids from typhoid endotoxin on the activity of some liver enzymes. | sublethal doses of typhoid endotoxin distinctly increased the activities of glutamate dehydrogenase and histidine ammonium lyase in liver tissue of mice within 3 hrs and the tyrosine transaminase activity within 6 hrs after a single intraperitoneal administration. within 24 hrs normalzation of these enzyme activities and a decrease in the urocaninase activity were observed in liver tissue. lipid a, obtained from the endotoxin, activated glutamate dehydrogenase and histidine ammonium lyase, inhib ... | 1975 | 3021 |
| study of the amount of antibody-forming and rosette-forming cells in different states of natural immunity in mice. | | 1976 | 13562 |
| emergency prophylaxis of typhoid using the vi-antigen of typhoid bacteria. | | 1976 | 13578 |
| the rotation aeration system (fuchs system) for the treatment of liquid animal and municipal waste. 4. hygienic studies with the rotation aeration of municipal sewage. | | 1976 | 7232 |
| 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 effect of temperature, solids content and ph on the survival of salmonellas in cattle slurry. | | 1976 | 8190 |
| 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 |
| effect of glass on ph-dependent stability of typhoid vaccine. | vaccines made from the ty-2 strain of salmonella typhosa were tested periodically for stability of ph and of potency. the acetone-treated cultures prepared in buffered saline solutions retained potency beyond 30 months of storage at 0 to 5 c. similar vaccines in unbuffered saline solutions lost potency coincident with increase of alkalinity. vaccines packaged in united states pharmacopeia borosilicate glass vials retained potency and ph stability, whereas those in type iii united states pharmaco ... | 1976 | 9421 |
| 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 |
| age-dependent resistance of chicken of salmonella in vitro: antibacterial activity of lysed granule fraction of splenic adherent cells. | lysed granule fraction was prepared from splenic adherent cells from 0-day-old to 2-month-old chickens and was examined antibacterial activity to salmonella pullorum and salmonella sentfenberg. the activity of lysed granule fraction from 2-month-old chickens was exhibited at ph 5.0 but not exhibited at ph 6.0 or 7.0 to both serotypes of salmonella. at ph 5.0, lysed granule fraction from 0-day-old chickens revealed little antibacterial activity to s. pullorum but the activity increased with incre ... | 1977 | 15389 |
| helical transformations of salmonella flagella in vitro. | | 1976 | 9518 |
| 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 |
| 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 |
| 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 |
| the occurrence of salmonellas, mycobacteria and pathogenic strains of escherichia coli in pig slurry. | ninety-eight samples of pig slurry from 54 farms were examined for the presence of salmonellas, porcine enteropathogenic strains of haemolytic escherichia coli and mycobacteria. salmonellas were isolated from 12 farms (22%) and enteropathogenic e. coli from 13 farms (24%). pathogenic mycobacteria were not isolated. salmonellas were isolated from 7 of 16 farms (44%) stocked with 'minimal disease' pigs compared with only 5 of 38 farms (13%) stocked with conventionally reared pigs. conversely enter ... | 1976 | 10332 |
| mutagenicity of fluroxene. | | 1976 | 10759 |
| a simple procedure for screening of salmonellae using a semi-solid enrichment and a semi-solid indicator medium. | | 1976 | 11204 |
| 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 |
| the role of microflora in development of graft-versus-host disease. | | 1976 | 11583 |
| application of a direct spectrophotometric assay employing a chromogenic substrate for tryptophanase to the determination of pyridoxal and pyridoxamine 5'-phosphates. | | 1976 | 11704 |
| properties of tyrosine-inhibitable 3-deoxy-d-arabinoheptulosonic acid-7-phosphate synthase from salmonella. | tyrosine-inhibitable 3-deoxy-d-arabinoheptulosonic acid-7-phosphate (dahp) synthase was purified to homogeneity without significant loss of sensitivity to inhibition by tyrosine from an operator-constitutive strain (tyroc) of salmonella. the enzyme had an apparent molecular weight of 76,000 by gel filtration and a subunit molecular weight of 40,000 by sodium dodecyl sulfate-gel electrophoresis and by reaction with dimethyl suberimidate. it had an isoelectric point of 4.68. inhibition by l-tyrosi ... | 1977 | 12135 |
| 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 |
| 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 |
| the immune response in cirrhotic rats. antigen distribution, humoral immunity, cell-mediated immunity and splenic suppressor cell activity. | the immunological disturbances occurring as a result of liver disease have been studied in an animal model of cirrhosis. the mononuclear phagocytic cells of the normal liver phagocytose large amounts of antigen irrespective of whether that antigen is injected directly into the portal or into the systemic circulations. the liver therefore acts as a filter 'in series' and 'in parallel' with the spleen and reduces the immunogenicity of antigens entering the organism by either of these routes. in ra ... | 1976 | 12899 |
| detection of salmonella antigens in the neutralization reaction (anr). | | 1977 | 17975 |
| flagellar transformations at alkaline ph. | | 1976 | 13224 |
| structure and assembly of the capsid of bacteriophage p22. | identification of the genes and proteins involved in phage p22 formation has permitted a detailed analysis of particle assembly, revealing some unexpected aspects. the polymerization of the major coat protein (gene 5 product) into an organized capsid is directed by a scaffolding protein (gene 8 product) which is absent from mature phage. the resulting capsid structure (prohead) is the precursor for dna encapsidation. all of the scaffolding protein exits from the prohead in association with dna p ... | 1976 | 13434 |
| the ability of enteric bacteria to catalyze the covalent binding of bile acids and cholesterol to dna and their in ability to metabolize benzo(a)pyrene to a binding product and to known metabolites. | the capacity of enteric bacteria (e. coli, salmonella, pseudomonas, shigella and klebsiella) to catalyze the covalent binding of benzo(a)pyrene (bp), cholic acid, deoxycholic acid and cholesterol was investigated. in general, these bacteria were incapable of activating bp to a covalently bound product with calf thymus dna. metabolism studies of bp by fluorometric assay failed to indicate any accumulation of bp-3-hydroxy in the incubation medium. detailed metabolic investigation with high-pressur ... | 1977 | 19150 |
| effect of sera from immunologically altered mice on phytohemagglutinin-induced mouse lymphocyte transformation. | the dna-synthetic response of mouse spleen cells to phytohemagglutinin in vitro is depressed by the addition of normal mouse serum. the effects of sera from mice that had been modified immunologically were examined. increased depressive activity was found in sera from nude mice and from mice recently treated with anti-thymocyte globulin, but no change was found in sera from thymectomized, irradiated, bone marrow-reconstituted mice, nor from lethally or sublethally irradiated or cyclophosphamide- ... | 1976 | 13697 |
| 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 |
| 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 |
| a sensitive substrate for the clotting enzyme in horseshoe crab hemocytes. | an endotoxin-activated hemocyte lysate from horseshoe crab (tachypleus and limulus) was found to hydrolyze specifically bz-ile-glu-gly-arg-p-nitroanilide, which was recently introduced as the substrate for assay of the blood coagulation factor, factor xa. further, this amidase activity increased by increasing the concentration of bacterial endotoxin (salmonella minnesota r595) added to the lysate. thus, the measurement of the amidase activity in the hemocyte lysate can be very useful to detect a ... | 1977 | 19439 |
| 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 |
| bactericidal activity in conventional or decontaminated mice undergoing gvhd or radiation-induced injury. | | 1976 | 14846 |
| 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 |
| effect of capsular polysaccharide of klebsiella pneumoniae on host resistance to bacterial infections. i. induction of increased susceptibility to infections in mice. | when klebsiella pneumoniae capsular polysaccharide (cps-k) from type 1, kasuya strain, was injected intraperitoneally (i.p.) immediately before i.p. bacterial challenge, the survival time of mice infected with salmonella enteritidis nub 1 (virulent strain) was shortened and the mortality rate for mice infected with s. enteritidis nub 31 (avirulent strain) was enhanced. the promotion of infection with s. enteritidis nub 1 by cps-k depended upon its dose, the effect of cps-k being demonstrable up ... | 1976 | 9528 |
| regulation of tyrosine and phenylalanine biosynthesis in salmonella. | several types of 4-fluorophenylalanine resistant mutants were isolated. in one type of mutant dahp synthetase (tyr) and prephenate dehydrogenase were coordinately derepressed. the mutation was linked to arof and tyra and was cis- dominant by merodiploid analysis, thus confirming that it is an operator constitutive mutation (tyroc). a second type of mutation showed highly elevated levels of tyrosine pathway enzymes which were not repressed by l-tyrosine. it was unlinked to tyra and arof, and was ... | 1976 | 9783 |
| defence against bacterial drug resistance. | | 1976 | 10047 |
| 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 |
| 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 |
| effect of ph upon the activity of cefoxitin. | | 1977 | 23373 |
| 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 |
| 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 |
| mechanism of in vitro mutagenic activation and covalent binding of n-hydroxy-2-acetylaminofluorene in isolated liver cell nuclei from rat and mouse. | | 1978 | 26463 |
| 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 |
| bacterial endocarditis: clinical and bacteriological aspects and prognostic factors. | the microbiological, clinical and therapeutic aspects of all (71) cases of bacterial endocarditis admitted to the hôpital cantonal, geneva, between august 1970 and october 1974 were reviewed: there was a definite trend towards higher prevalence of acute cases compared to subacute cases. the pathogenic role of s. epidermidis, mostly in cases of prosthetic valve endocarditis, could be demonstrated in several cases. when defined initially by microbiological criteria only, acute endocarditis were ch ... | 1977 | 17156 |
| preenrichment procedure for detection of salmonella in gelatin. | trypticase soy broth was superior to nutrient and lactose broths as a preenrichment medium for the detection of salmonella in artificially and naturally contaiminated gelatin. the detection rate for salmonella were further enhanced when homogenization of the gelatin-broth mixture was accomplished by the use of gelatinase rather than by heating of 45 degrees c. detection rats were also increased by adjusting the ph of the gelatin-broth mixture of 7.0, optimum ph for gelatinase (ec 3.4.23.2) activ ... | 1977 | 17457 |
| on the aetiology of gastric cancer: mutagenicity of food extracts after incubation with nitrite. | | 1977 | 17566 |
| 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 |
| 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 |
| mild alkaline hydrolysis of lipopolysaccharide endotoxin enhances its mitogencity for murine b cells. | mild alkaline hydrolysis was found to enhance the mitogenicity of lipopolysaccharide endotoxin for murine b lymphocytes. alkaline treated lipopolysaccharide also retained its property as a polyclonal activator. whereas this treatment reduced the lethality of endotoxin for mice, its toxicity for lymphocytes cultured in the absence of fetal calf serum was increased. lipid analysis indicated that there were no significant changes in the fatty acids of lipid a, but particle size was significantly re ... | 1977 | 18405 |
| 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 |
| 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 |
| bacterial recombination. | the most perspective trends in studying the mechanisms of genetic exchanges in bacteria are discussed. they are the following. 1. comparison of the recombination stages in various biological phenomena such as transformation, transduction (generalized), conjugation (common and single-stranded) and transfection. 2. characterization of genetic determinants and basic enzymes of the recombination process in rec-systems of different bacteria. 3. determination of some peculiar features of the intrageni ... | 1977 | 19345 |
| 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 |
| cross-protective immunity to gram-negative bacilli: studies with core glycolipid of salmonella minnesota and antigens of streptococcus pneumoniae. | two immunoprophylactic approaches to the control of infections caused by gramnegative bacilli were evaluated by study of experimental infections in animals. the core glycolipid antigen derived from the re mutant of salmonella minnesota r595 is shared by virtually all enteric bacteria, and immunization with this endotoxin protects against the hemodynamic sequelae of bacterial infection and pyrexia without enhancing intravascular clearance of bacteria. the degree of protection afforded by active a ... | 1977 | 19538 |
| genetics of the (gram-negative) bacterial surface. | | 1978 | 27815 |
| glutamine synthetase from salmonella typhimurium: manganese(ii), substrate, and inhibitor interaction with the unadenylylated enzyme. | | 1977 | 20051 |