| 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 |
| dna of bacillus subtilis bacteriophage spp1: physical mapping and localization of the origin of replication. | the genome of bacillus subtilis bacteriophage spp1, a linear, 28.5-megadalton dna duplex, was mapped by analysis with the restriction endonucleases endo r.sal i, sma i, xba i, bgl i, bgl ii, and ecori. the spp1 genome, like that of the salmonella typhimurium phage, p22, was found to be a terminally repetitious, circularly permuted molecule. 6-(p-hydroxyphenylazo)uracil, a selective, reversible inhibitor of spp1 dna synthesis, was exploited to synchronize the initiation of genome replication and ... | 1978 | 104053 |
| 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 |
| a lipopolysaccharide-binding cell-surface protein from salmonella minnesota. isolation, partial characterization and occurrence in different enterobacteriaceae. | 1. protein extracts obtained from salmonella minnesota re mutant cells by treatment with edta/nac1 solution contain a protein which exhibits high affinity to bacterial lipopolysaccharides. the isolation and partial characterization of this lipopolysaccharide-binding protein is described. 2. the protein was purified from edta extracts by a two-step procedure consisting of ion-exchange chromatography on cm-sephadex and preparative polyacrylamide gel electrophoresis at ph 9.5. the yield of the tota ... | 1979 | 111933 |
| redox potential-dependent nitrite metabolism by salmonella typhimurium. | salmonellae are generally resistant to the inhibitory effects of nano2. removal of the lipopolysaccharide of salmonella typhimurium by ethylenediaminetetraacetic acid pretreatment did not result in subsequent inhibtion of growth by nano2, indicating that lipopolysaccharide does not function to exclude nano2 from the cell. nano2 disappeared from the medium while the cells were growing, but, after stationary phase was reached, no further losses were observed unless the ph was maintained above 7.0. ... | 1979 | 114115 |
| differences in the genetic control of primary and secondary antibody responses. | primary and secondary antibody responses to f and s antigens of salmonella typhimurium have been studied in h and l lines of mice genetically selected for primary reponse to sheep erythrocytes (se) (selection i). the range of interline separation obtained (non-specific effect of selection i) was as large as for the selection antigen in the primary response to f antigen and slightly smaller in the primary response to s antigen. for these two antigens the interline difference was reduced after boo ... | 1979 | 115781 |
| influence of a sub-therapeutic level of virginiamycin in feed on the incidence and persistence of salmonella typhimurium in experimentally infected swine. | | 1979 | 115823 |
| selective neutralization by antiinterferon globulin of macrophage activation by l-cell interferon, brucella abortus ether extract, salmonella typhimurium lipopolysaccharide, and polyanions. | | 1979 | 116771 |
| age-related defense against infection with intracellular pathogens. | young adult (6--12 weeks old) and aged (20--24 months old) nmri mice were infected with various intracellular parasites. the following results were obtained: (1) after a sublethal infection with listeria monocytogenes, aged mice were found to show a resistance similar to that of young adults. a challenge infection with this pathogen was followed by specific immunity of long duration in both age-groups. (2) on the other hand, young animals were significantly more resistant to salmonella typhimuri ... | 1979 | 116909 |
| induction of bacteriolytic enzyme from pyocinogenic pseudomonas aeruginosa and its enzymatic properties. | mitomycin c induced a pyocinogenic pseudomonas aeruginosa p15 to produce a bacteriolytic enzyme, pr1-lysozyme, together with pyocin r1. no significant accumulation of the enzyme was observed inside the induced cells. the enzyme was partially purified by acrinol treatment and amberlie cg-50 column chromatography. the mode of action of the enzyme on the host bacterial cells as well as on micrococcus lysodeikticus cells or peptidoglycan isolated from salmonella typhimurium, was compared with that o ... | 1978 | 117282 |
| mutagenicity of nitrosodiethanolamine on salmonella typhimurium. | nitrosodiethanolamine was examined in the ames assay for bacterial mutagens. in absence of s9 activation a mutagenic effect was found. | 1979 | 117355 |
| mutagenicity tests with griseofulvin. | griseofulvin was studied for its ability to induce structural chromosomal aberrations in germ and somatic cells of the male mouse. it was also tested for its capacity to produce his+ revertants in salmonella typhimurium. all tests yielded negative results, whereas highly significant effects were recorded in control assays with thio-tepa. | 1979 | 117357 |
| mutagenic and dna-damaging effects of n-alkyl-n-(alpha-acetoxyalkyl)nitrosamines, models for metabolically activated n,n-dialkylnitrosamines. | mutagenic and dna-damaging effects of a series of n,n-dialkylnitrosamines monosubstituted at the alpha-carbon with an acetoxyl group were tested in salmonella typhimurium, escherichia coli, and bacilus subtilis in the absence of metabolic activation system. the compounds comprised 8 n-alkyl-n-(acetoxymethyl)nitrosamines (alkyl=methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, or tert-butyl) and n-butyl-n-(1-acetoxybutyl)nitrosamine. all the compounds, except one with a tert-butyl gro ... | 1979 | 118074 |
| mutagenicity and metabolism of dimethylnitrosamine and benzo[alpha]pyrene in tissue homogenates from inbred syrian hamsters treated with phenobarbital, 3-methylcholanthrene or polychlorinated biphenyls. | there are significant differences between mice and hamsters in polycyclic hydrocarbon and nitrosamine metabolism. homogenates of liver, lung and intestinal mucosa from 6 strains of syrian golden hamster were compared for their ability to metabolize benzo[alpha]pyrene (bp) and dimethylnitrosamine (dmn) to mutagens. females of strains mha/sslak, lsh/sllak, cb/sslak, pd4/lak lhc/lak and lak:lvg (syr) were either untreated or received phenobarbital (pb), 3-methylcholanthrene (mc) or polychlorinated ... | 1979 | 118380 |
| effects of the hepatic s9 fraction from aroclor-1254-treated rats on the mutagenicity of benzo[alpha]pyrene and 2-aminoanthracene in the salmonella/microsome assay. | the mutagenicity of benzo[alpha]pyrene and 2-aminoanthracene for salmonella typhimurium ta98 in the plate-incorporation test was studied using liver s9 from untreated and aroclor-1254-treated rats. the induction of liver s9 protein, arylhydrocarbon hydroxylase (ahh), and cytochrome p448/450 was followed with time. there was no change in protein concentrations with induction; ahh and cytochrome levels were increased at 1, 3, 5 and 7 days post aroclor treatment. benzo[alpha]pyrene mutagenicity was ... | 1979 | 118381 |
| studies on the mutagenicity of p-phenylenediamine in salmonella typhimurium. presence of pcb's in rat-liver microsomal fraction induced by aroclor. | the mutagenicity of fresh solutions of p-phenylenediamine (ppd) and aroclor 1254 was investigated. the histidine-requiring strains of salmonella typhimurium were used in the absence and presence of uninduced and/or aroclor-induced rat-liver homogenate. the presence of polychlorinated biphenyls (pcbs) was also examined by chromatographic methods in aroclor-induced rat-liver homogenate. in the absence of metabolic activation, as well as in the presence of uninduced rat-liver homogenate, ppd was no ... | 1979 | 118383 |
| mutagenicity of skin tanning lotions. | two lotions that tan skin in the absence of sunlight and their active ingredient, dihydroxyacetone (dha), are mutagenic in salmonella typhimurium strain ta100 without metabolic activation. however, addition of s-9 mix that contains aroclor 1254-induced rat hepatic microsomes enhances significantly the mutagenic activity of all three agents. both lotions and dha also cause primary dna damage as determined by the rec-assay in bacillus subtilis. the potential human health hazard of these lotions is ... | 1979 | 121138 |
| differential mutagenicities of triamino benzenes against salmonella typhimurium ta98 in the presence of s9 fractions from polychlorinated biphenyls-, phenobarbital- or 3-methylcholanthrene-pretreated rats, hamsters and mice. | mutagenicity of 6 aminobenzene derivatives against salmonella typhimurium ta98 was studied in the presence of various s9 fractions. s9, which has been prepared form the livers of rats, hamsters and mice after pretreatment with different types of inducers; polychlorinated biphenyls, phenobarbital and 3-methylcholanthrene, was used as the methabolic activating enzyme in this mutation assay. the s9 fractions from 3-methylcholanthrene-treated rats and mice are most useful for mutation induction by t ... | 1979 | 121315 |
| [comparative study of microbial methods for the detection of genetic toxicity]. | it is important to have a rapid and accurate method to detect the toxic action of drugs and chemical compounds used by man. a comparative study with two microbial systems was carried out: one using salmonella typhimurium and the other using bacillus subtilis. the 1-8-dihydroxyantraquinone was the tested drug and the n-methyl-n'-nitro-n-nitrosoguanidine and the 2-aminofluorene were used as control substances. these compounds were used as such or after previous transformation by a microsomal syste ... | 1979 | 122387 |
| typhoid cardiac involvement. | three cases of typhoid cardiac complications are reported. salmonella typhi was the aetiological agent in all three; the discovery of 3 patients over a period of 18 months merits special interest, especially since typhoid fever is endemic in the area concerned. the significance of the complication reported here is further enhanced by absence of similar specific cases in the english literature dealing with cardiac salmonellosis. one of the cases described in this article, the only fatality of the ... | 1975 | 123083 |
| subunit composition, function, and spatial arrangement in the ca2+-and mg2+-activated adenosine triphosphatases of escherichia coli and salmonella typhimurium. | | 1975 | 124154 |
| [protection by oral vaccination of mice with an avirulent live strain of salmonella typhimurium]. | before determining the quantity of mouse intestinal secretory iga after oral vaccination, we have tried to find the best conditions of immunization with an avirulent s. typhimurium strain given by oral route. the results show the superiority of the live vaccin with respect to the heat-killed one. | 1975 | 126768 |
| salmonella typhimurium hfra, a mutant in which adenosine triphosphate can drive amino acid transport but not energy-dependent nicotinamide nucleotide transhydrogenation. | in contrast with wild-type salmonella typhimurium lt2, strain hfra did not have atp-driven energy-dependent transhydrogenase activity, although atp-dependent quenching of atebrin fluorescence was normal. respiration-dependent and energy-independent transhydrogenase, and ca2+-activated atpase (adenosine triphosphatase) activities were similar in both strains. purified atpases from the two strains had similar specific activities, similar subunit polypeptides, and were equally effective in restorin ... | 1975 | 128357 |
| mechanisms of siderophore iron transport in enteric bacteria. | uptake of 55fe- and 3h-labeled siderophores and their chronic analogues have been studied in salmonella typhimurium lt-2 and escherichia coli k-12. in s. typhimurium lt-2, at least two different mechanisms for siderophore iron transport may be operative. uptake of 55fe- and 3h-labeled ferrichrome and kinetically inert lambda-cis-chromic [3h]deferriferrichrome by the s. typhimurium lt-2 enb7 mutant, which is defective in the production of its native siderophore, enterobactin, appears to occur by ... | 1976 | 131124 |
| mutagenicity assays on fluorescent whitening agents using microorganisms. | six fluorescent whitening agents (fwas) have been re-examined for their activity as inducers of cytoplasmic petite mutants and mitotic gene conversion in diploid yeast saccharomyces cerebisiae and reversion from auxotrophy to prototrophy in neurospora crassa, escherichia coli and salmonella typhimurium. the results provide no indication that the fwas examinded produce mutagenic changes or any other alterations in the gene material. in a recent re-examination with salmonella using the method of a ... | 1975 | 132347 |
| [the examination of lysogenic properties of salmonella typhimurium strains; utilization for further differentiation of phage types (author's transl)]. | | 1976 | 136307 |
| mutagenicity of streptozotocin and several other nitrosourea compounds in salmonella typhimurium. | the following nitrosourea compounds were compared for their ability to induce mutation (to histidine independence) in the histidine-requiring auxotroph salmonella typhimurium his g46: mnu, streptozotocin (sz, streptozocin) and its analogs sza1 and sza2, and the antitumor drugs bcnu, ccnu and dcnu. at equitoxic doses sz, sza1, sza2 and mnu were almost equally mutagenic causing 150, 42, 140 and 170 mutants/106 survivors at 20% lethal dose (id20) although, on a wieght basis, sz was the most mutagen ... | 1976 | 138082 |
| association of salmonella mutants with germ-free rats: characterization of the reverse mutational response to 2-nitrofluorene. | salmonella typhimurium strain ta1538 described by ames, in association with otherwise germ-free rats, colonizes the gastrointestinal tract. the revertants enumerated in the feces of each of these rats varies in a coordinated manner in relation to the day on which the measurement is made. in response to the oral ingestion of a single dose of 2-nitrofluorene, the concentration of revertants in the feces increases and then returns essentially to control values within 6 days. when these rats are cha ... | 1976 | 138083 |
| mammalian host- and fluid-mediated mutagenicity assays of captan and streptozotocin in salmonella typhimurium. | the mutagenicity of captan and of streptozotocin was tested in vivo by reversion of hisg46 base-pair substitution histidine auxotrophs of salmonella typhimurium in the peritoneal cavity or in blood, plasma or urine of rats or mice. genetic response was determined by the frequency of revertants (quantitative test) or by the number of revertants per plate (semiquantitative test). in quantitative hma captan gave negative results following 3 hourly 500 mg/kg s.c. doses or 1000 mg/kg oral dose in mic ... | 1977 | 138085 |
| mutation induction by the antischistosomal drug f30066 in various test systems. | the genetic activity of furapromidium (f30066), an antischistosomal drug, was studied in salmonella typhimurium, saccharomyces cerevisiae, neurospora crassa and cultured chinese hamster cells. the results show that f30066 induces gene mutations in s. typhimurium, n. crassa and chinese hamster cells. this compound also causes gene conversions in s. cerevisiae. | 1977 | 138086 |
| [evolution of mouse intestinal and blood immunoglobulins after oral route vaccination]. | the authors have studied the mice immunoglobulins level after vaccination by oral route with a killed-pathogenic strain of salmonella typhimurium and an avirulent mutant of the same bacteria. the obtained results show an increase of the intestinal iga and igg1 levels and a slighter one of sera igg between the 10 th and 30 th day following immunization. no correlation was observed concerning the igm, igg and iga levels and the mice protection against a challenge of pathogenic bacteria. | 1977 | 142559 |
| use of transferrin-iron enterobactin complexes as the source of iron by serum-exposed bacteria. | two smooth and six rough strains of salmonella typhimurium with progressively smaller amounts of sugar and protein in their outer membrane were tested for degree of virulence in normal and iron-injected mice and for ability to acquire iron in mammalian sera. the rate of mortality showed that bacterial virulence for mice was lowered with progressive decrease of outer-membrane sugar and protein. iron injections increased the rate of mortality in mice infected either with smooth strains or with sup ... | 1977 | 144704 |
| siderophores: diverse roles in microbial and human physiology. | siderophores, defined as high affinity iron(iii) ion transport agents, and their cognate membrane-bound receptor complexes, occur in the enteric bacteria escherichia coli and salmonella typhimurium. the total system is tightly regulated by iron repression. the transport properties of the specific siderophores enterobactin and ferrichrome (which is not made by these particular enteric bacteria) have been examined in detail. in e. coli the outer membrane receptor for ferrichrome is programmed by t ... | 1976 | 145937 |
| [mutagenicity of the metabolites of the epoxide-diol pathway of safrole and its analogs. study on salmonella typhimurium]. | mutagenicity of the metabolites of the expoxide-diol pathway of safrole and analogues was studied on ames' strains with ames' method. safrole, eugenol, eugenolmethylether, estragol, allylbenzene and 1'-hydroxysafrole, are not mutagen on ta 1535, ta 100 (point mutation) and ta 1537, ta 1538, ta 98 (frameshift mutations) without activation system. the corresponding epoxides that we have synthetized, are mutagens and inducers of point mutation in ta 1535 and ta 100. dose-effect curves show differen ... | 1977 | 146546 |
| the immunological relationship between filtrable agent, salmonella and murine leukosis. | salmonella typhimurium was invariably isolated from our j strain murine leukosis. immunization of d103 mice with either inactivated salmonella typhimurium or the cell-free extract of leukosis inhibited the transplantation of leukosis. the adoptive immunization of d103 mice with spleen cells of strong a mice immunized with either salmonella or the cell-free extract of leukosis inhibited the transplantation of leukosis. the addition of either salmonella or the cell-free extract of leukosis inhibit ... | 1977 | 147604 |
| constitutive expression of the iron-enterochelin and ferrichrome uptake systems in a mutant strain of salmonella typhimurium. | two high-affinity iron uptake systems are known in salmonella typhimurium, one utilizing iron-enterochelin and the other utilizing ferrichrome. it has been shown previously that expression of several elements of the iron-enterochelin uptake system are regulated by the iron content of the medium, with growth in high-iron medium resulting in repression of enzymes of enterochelin synthesis and degradation and of the ability of whole cells to take up iron-enterochelin. in this study we describe a mu ... | 1978 | 151097 |
| mutagenicity testing of benomyl, methyl-2-benzimidazole carbamate, streptozotocin and n-methyl-n'-nitro-n-nitrosoguanidine in salmonella typhimurium in vitro and in rodent host-mediated assays. | the fungicide benomyl and its commercial preparations fundazol 50wp and benlate 50wp and the benomyl metabolite methyl-2-benzimidazole carbamate and its commercial preparation mbc 50wp were tested for mutagenicity in in vitro spot tests, in microsomal plate assay, in liquid-culture treatments, or in rodent host-mediated assay. the base-pair substitution salmonella typhimurium mutant hisg46 and the hisg46-bearing uvrb excision-repair-deficient mutants ta100, ta1530, ta1535 or ta1950 were used as ... | 1978 | 151228 |
| [immunologic reactions in vitro to abnormal forms of salmonella typhimurium induced in the presence of fosfomycin]. | | 1978 | 154074 |
| the value of plasmid studies in the epidemiology of infections due to drug-resistant salmonella wien. | since 1969 strains of salmonella wien that are resistant to multiple antibacterial drugs have caused widespread epidemics of enteritis in europe and north africa. of 113 british strains examined between january 1970 and january 1977, 67 were multi-resistant. these strains and 22 strains from six other countries were examined to determine their plasmid content. two plasmids were found in the vast majority of strains: an fime factor, conferring resistance to ampicillin, chloramphenicol, kanamycin, ... | 1979 | 155714 |
| changes in the immunoglobulin levels of the mouse gut and serum during conventionalisation and following administration of salmonella typhimurium. | increasess in all immunoglobulin classes, except igm, were observed in the sera of specific pathogen-free (spf) mice beginning 10 days after their removal from barrier conditions. concentrations of serum immunoglobulins, comparable with those of conventional mice, were obtained in these animals between 21 and 35 days. following the removal of germ-free mice from their sterile isolaters, their intestinal iga levels increased over 35 days to attain levels found in conventional animals. a marked in ... | 1978 | 156538 |
| enterochelin (enterobactin): virulence factor for salmonella typhimurium. | the ability of salmonella typhimurium to synthesize enterochelin (enterobactin; ent) affects its capacity to grow both in vivo and in vitro. an ent mutant (96-1), blocked in the conversion of chorismate to 2,3-dihydroxybenzoate, was derived from sr-11, a strain of high mouse virulence. this mutant was unchanged in the other characteristics tested: colonial, biochemical, antigenic, and cellular. in contrast to sr-11, growth of this mutant in complement-inactivated human serum was strongly inhibit ... | 1979 | 156695 |
| tumor induction in swiss mice by filtrable agent and salmonella typhimurium. | combined inoculation of a cell-free extract of leukotic tissue of d103 mice and salmonella typhimurium into adult swiss mice induced leukosis and solid tumors. the induced solid tumors were histologically multifarious, and were transplantable in swiss mice, but not in other strains of mice. | 1979 | 160187 |
| response to a metal ion-citrate complex in bacterial sensing. | salmonella typhimurium responds chemotactically to gradients of divalent cations in the presence of citrate ions. the actual chemoeffector is the citrate-metal ion complex, which acts as an attractant. citrate (which is also a chemoeffector for salmonella) and the citrate-metal ion complex are recognized by different receptors. the response of salmonells, which can transport citrate through its membrane, is quite different than that of escherichia coli, which cannot. | 1979 | 160411 |
| gene for the rna polymerase sigma subunit mapped in salmonella typhimurium and escherichia coli by cloning and deletion. | the genes for the rna polymerase sigma subunit (rpod) and dna primase (dnag) of salmonella typhimurium have been cloned into lambda vectors. combined restriction, deletion and functional analysis of the cloned fragment allows us to map the genes precisely on the fragment, establishes the direction in which rpod is transcribed, and reveals the existence of at least one new gene in the vicinity. a closely homologous, smaller fragment of escherichia coli dna, also cloned into lambda, contains rpod ... | 1979 | 160566 |
| [results of 28 years of observations of the circulation of biologically nonuniform varieties of salmonella typhimurium]. | | 1978 | 161090 |
| inactivation of viruses and bacteria by ozone, with and without sonication. | selected organisms with public health significance were placed in a reaction chamber for treatment by ozonation, by ozonation and sonication, by sonication, or by sonication during oxygenation. vesicular stomatitis virus, encephalomyocarditis virus, gdvii virus, staphylococcus aureus, pseudomonas fluorescens, salmonella typhimurium, enteropathogenic escherichia coli, vibrio cholerae, and shigella flexneri were inactivated by treatment with ozone. when microorganisms were suspended in phosphate-b ... | 1975 | 163616 |
| control of expression of the pyr genes in salmonella typhimurium: effects of variations in uridine and cytidine nucleotide pools. | the differential rate of synthesis of five of the pyrimidine biosynthetic enzymes coded for by pyrb-f, and the endogenous concentrations of the individual pyrimidine nucleotides were determined in specially constructed mutants of salmonella typhimurium. in the mutants employed the different pyrimidine nucleotide pools may be manipulated individually during exponential growth. the results obtained indicate the following. (i) the expression of pyrb, pyre, and pyrf is controlled by a uridine nucleo ... | 1975 | 163814 |
| mechanism of the suppressive effect of interferon on antibody synthesis in vivo. | mouse interferon preparations significantly suppress the in vivo antibody response to sheep red blood cells (srbc), a thymus-dependent antigen, and to salmonella typhimurium lipopolysaccharide (lps), a thymus-independent antigen. it is also possible to effect the late responses of antigen sensitive "memory" cells observed during secondary immunization by administration of interferon prior to primary immunization. the immunosuppressive activity of interferon was time- and dose-dependent. maximum ... | 1975 | 163863 |
| carbamylphosphate synthetase from salmonella typhimurium. regulations, subunit composition, and function of the subunits. | carbamylphosphate synthetase was purified to homogeneity from a derepressed strain of salmonella typhimurium by a procedure based on affinity chromatography employing immobilized glutamine. the enzyme catalyzes the synthesis of carbamylphosphate from either ammonia or glutamine together with atp and bicarbonate. the atp saturation curve of either nitrogen donor is sigmoidal (n equals 1.5) but the affinity for atp is higher with ammonia. in addition to the feedback inhibition by ump and activatio ... | 1975 | 166993 |
| inactivation of salmonella phosphoribosylpyrophosphate synthetase by oxidation of a specific sulfhydryl group with potassium permanganate. | phosphoribosylpyrophosphate synthetase from salmonella typhimurium contains four cysteine residues per subunit. three of these react readily with 5, 5'-dithiobis(2-nitrobenzoic acid) (dtnb), forming an active derivative with kinetic and physical properties similar to the native enzyme, but one reacts only under denaturing conditions. stoichiometric amounts of kmno4 inactivate the dtnb-treated enzyme. the loss of activity is correlated with the oxidation of the remaining cysteinyl group to cystei ... | 1975 | 167011 |
| mutagenicity testing with salmonella typhimurium strains. ii. the effect of unusual phenotypes on the mutagenic response. | the enhanced sensitivity of some salmonella typhimurium strains to the mutagenic action of a number of chemicals appears to be due to the defect in the uvrb gene product and not to an inability to produce h-2-s or to the absence of formic acid hydrogenlyase which also characterizes these strains. | 1975 | 167280 |
| cyclic 3', 5'-adenosine monophosphate phosphodiesterase mutants of salmonella typhimurium. | positive selection procedures for mutants of salmonella typhimurium lacking cyclic 3', 5'7-adenosine monophosphate (camp) phosphodiesterase have been devised. the gene (cpd) coding for this enzyme has been located on the chromosome and shown to be 25% co-transducible with metc using phage p22. the mutants have been used to investigate the role of the enzyme in the control of genes whose expression is known to be dependent on camp. significant alterations in the regulation of some but not others ... | 1975 | 168178 |
| pyrr identical to pyrh in salmonella typhimurium: control of expression of the pyr genes. | mutants of salmonella typhimurium showing constitutive synthesis of the pyrimidine biosynthetic enzymes coded for by the pyra-f genes (g. a. o'donavan and j. c. gerhart, 1972) have been reinvestigated. the high rate of expression of the pyrb-f genes in these mutants as well as their pyrimidine excretion is shown to be due to mutations in the gene pyrh encoding uridine 5'-monophosphate kinase. thus, the term pyrr used for these mutants should be replaced by the designation pyrh. | 1975 | 169229 |
| tryptophan biosynthesis in salmonella typhimurium: location in trpb of a genetic difference between strains lt2 and lt7. | salmonella typhimurium prototrophs carrying a trpr mutation synthesize tryptophan biosynthetic enzymes constitutively. when feedback inhibition of anthranilate synthetase but not 5'-phosphoribosylpyrophosphate phosphoribosyltransferase activity was by-passed by growing cells on media supplemented with anthranilic acid, all trpr prototrophs overproduced and excreted tryptophan. however, the rate of tryptophan production depended on both the ancestry of the trpr strain and the integrity of its trp ... | 1975 | 169230 |
| coordinate regulation of adenylate cyclase and carbohydrate permeases by the phosphoenolpyruvate:sugar phosphotransferase system in salmonella typhimurium. | adenylate cyclase (ec 4.6.1.1) and several carbohydrate permeases are inhibited by d-glucose and other substrates of the phosphoenolpyruvate:sugar phosphotransferase system. these activities are coordinately altered by sugar substrates of the phosphotransferase system in a variety of bacterial strains which contain differing cellular levels of the protein components of the phosphotransferase system: enzyme i, a small heat-stable protein, and enzyme ii. it is suggested that the activities of aden ... | 1975 | 169265 |
| action of polymyxin b on bacterial membranes: morphological changes in the cytoplasm and in the outer membrane of salmonella typhimurium and escherichia coli b. | though the primary action of the cationic antibiotic polymyxin b is against the membrane of susceptible bacteria, severe morphological changes are detected in the cytoplasm. using fluorescence microscopy and a mono-n-dansyl-polymyxin b derivative, we could demonstrate aggregations of the antibiotic with cellular material, possibly nucleic acids and/or ribosomes. these aggregations were only produced by minimum inhibitory or higher concentrations of the antibiotic as shown with salmonella and esc ... | 1975 | 169730 |
| regulation of gmp reductase in salmonella typhimurium. | the levels of guanosine 5'-phosphate reductase (ec 1.6.6.8) in salmonella typhimurium appear to be modulated by changes in the ratio of the adenine and guanine nucleotide pools. alterations of this ratio may be induced by high levels of guanosine in the culture medium or by genetic lesions in one of several purine interconversion enzymes, such as pur a or pur b mutants. the induction of the reductase requires transcription and translation processes and, in contrast to earlier observation with es ... | 1975 | 169910 |
| characterization of monkey peripheral neutrophil granules during infection. | rhesus monkey (macaca mulatta) neutrophils were shown to contain the azurophilic granule maker enzymes myeloperoxidase and beta-glucuronidase but were deficient in the specific granule markers alkaline phosphatase (akp) and lysozyme. isopycnic centrifugation of leukocyte homogenates on linear sucrose gradients resulted in cosedimentation of myeloperoxidase and beta-glucuronidase with an equilibrium density of 1.18. after an intravenous inoculation of monkeys with salmonella typhimurium akp activ ... | 1975 | 170208 |
| studies of the quaternary structure and the chemical properties of phosphoribosylpyrophosphate synthetase from salmonella typhimurium. | phosphoribosylpyrophosphate (prpp) synthetase (ec 2.7.6.1) was purified to virtual homogeneity from salmonella typhimurium cells by a modification of previously published procedures. the molecular weight of the subunit was determined to be 31,000 +/- 3,000 by polyacrylamide gel electrophoresis in sodium dodecyl sulfate and sedimentation equilibrium analysis of the enzyme dissolved in 6 m guanidine hydrochloride. the amino acid composition of the enzyme was determined. proline was identified as t ... | 1975 | 170262 |
| regulation of intracellular adenosine cyclic 3':5'-monophosphate levels in escherichia coli and salmonella typhimurium. evidence for energy-dependent excretion of the cyclic nucleotide. | sugars and other energy sources were found to lower intracellular concentrations of adenosine 3':5'-monophosphate (cyclic amp) in strains of escherichia coli and salmonella typhimurium which were deficient for cyclic amp phosphodiesterase. this effect required the presence of the specific transport system responsible for entry of that sugar into the cell and depended on the intracellular catabolic enzymes. metabolizable sugars were more effective than nonmetabolizable sugars in reducing cellular ... | 1975 | 170265 |
| mutants of salmonella typhimurium responding to cysteine or methionine: their nature and possible role in the regulation of cysteine biosynthesis. | nineteen mutants of salmonella typhimurium responding to either cysteine or methionine (cym) have been identified amongst cysteine (cys) and methionine (met) auxotrophs. their growth responses to known intermediates in the related pathways of cysteine and methionine biosynthesis and complementation patterns in abortive transduction tests divided the mutants into six groups. results of conjugation, cotransduction and deletion mapping experiments substantiated these groups, each of which carried a ... | 1975 | 170364 |
| altered dna synthesis in a mutant of salmonella typhimurium that channels bacteriophage p22 toward lysogeny. | pox-1, a mutant of salmonella typhimurium, strongly channels p22 toward lysogeny. viral dna synthesis in this slow-growing mutant is delayed to a greater extent than viral protein synthesis. the relative enhancement of c2 repressor synthesis results in much higher repressor/dna synthesis ratios in pox-1 than in wild-type cells. this probably accounts for the high frequency of lysogenization. | 1975 | 171446 |
| host influence on the activity of genes c1 and c3 in regulating the decision between lysis and lysogency in bacteriophage p22. | a polymyxin b-sensitive mutant of salmonella typhimurium (pox-1) channels all infecting wild-type p22 toward lysogenization. the efficiency of this channeling is sufficiently high that p22c+ (wild type) cannot form plaques on pox-1; phage mutants defective in repressor synthesis (p22c1, c2, c3) or refractory toward repressor (p22vir b) can form plaques. the lytic growth of all phages which have a functional c1 gene is retarded in pox-1; this retardation is seen even in phages which cannot make r ... | 1975 | 171449 |
| pathogenesis of salmonella-mediated intestinal fluid secretion. activation of adenylate cyclase and inhibition by indomethacin. | salmonella typhimurium, an organism that invades intestinal mucosa but does not elaborate a traditional enterotoxin, evokes ileal secretion by causing alterations in active sodium and chloride transport mechanisms. to evaluate the possibility that these changes in transport might be related to the adenylate cyclase-cyclic amp or na+-k+-adenosine triphosphatase (atpase) systems, mucosal adenylate cyclase, camp phosphodiesterase, na+-k+ and mg++ atpase activities, and camp concentrations were meas ... | 1975 | 172399 |
| cysteine biosynthesis in salmonella typhimurium: the presence of atp-sulfurylase and aps-kinase in various cysteine-requiring mutants. | enzymatic tests were performed on a series of cysteine-requiring mutants for the presence of the sulfate activating enzymes. atp-sulfurylase (sulfate adenylyltransferase ec 2.7.7.4) and aps-kinase (adenylylsulfate kinase ec 2.7.1.25). the enzymatic products adenosine 5'-[35s]sulfatophosphate and adenosine 3'-phosphate 5'-[35s]sulfatophosphate were identified by paper electrophoresis and measured quantitatively without elution from the paper. cys mutants mapping in cistrons, a, h, i, j, g, and ea ... | 1975 | 173451 |
| action of polymyxin b on bacterial membranes: phosphatidylglycerol- and cardiolipin-induced susceptibility to polymyxin b in acholeplasma laidlawii b. | to identify the polymyxin receptor molecules in the membranes of living microorganisms, fusion of intact acholeplasma laidlawii b with lipid vesicles was investigated according to the procedure of grant and mcconnell (1973). the naturally polymyxin-resistant a. laidlawii b was treated with phospholipid vesicles prepared from purified phospholipids of the polymyxin-susceptible salmonella typhimurium g30. a. laidlawii b absorbed between 15 and 45% of its own lipid content of the added tritium-labe ... | 1976 | 176930 |
| growth rate modulation of four aminoacyl-transfer ribonucleic acid synthetases in enteric bacteria. | the specific activities of arginyl- glutamyl- seryl-, and valyl-transfer ribonucleic acid (trna) synthetases were measured in the wild-type and mutant strains of salmonella typhimurium lt2 and escherichia coli b/r. in media restricted only by carbon and energy source availability, the specific activities of all four enzymes were proportional to the growth rate, with the exception of seryl-trna synthetase in s. typhimurium, which remained essentially constant. structural gene densities were calcu ... | 1976 | 177401 |
| the role of camp in flagellation of salmonella typhimurium. | a mutational alteration either in adenylate cyclase (cya-) or in cyclic-3'5'-amp (camp) receptor protein (crp-) rendered salmonella typhimurium incapable of producing flagella. the amount of mrna specific for flagellin in these mutants was almost negligible when assayed in an in vitro protein synthesizing system. a secondary mutation cfs, partially suppressing the cya- mutation, was identified among the revertants of cya-. a mutation in the same cistron as cfs resulted in a non-flagellate phenot ... | 1976 | 178991 |
| inhibition of growth and aspartokinase activity of salmonella typhimurium by thialysine. | thialysine (s-2-aminoethyl cysteine) is an analog of lysine and has been reported to inhibit the lysyl-trna synthetase activity of escherichia coli. this analog inhibits the growth of salmonella typhimurium when added to glucose minimal medium at concentrations of 1.25 mm or greater. the addition of lysine with thialysine restores the normal growth rate, whereas, methionine, valine, or leucine each enhances the growth inhibition casued by thialysine. enzyme assays demonstrate that thialysine inh ... | 1976 | 179582 |
| effects of crp mutations on adenosine 3',5'-monophosphate metabolism in salmonella typhimurium. | wild-type salmonella typhimurium could not grow with exogenous cyclic adenosine 3',5'-monophosphate (amp) as the sole source of phosphate, but mutants capable of cyclic amp utilization could be isolated provided the parental strain contained a functional cyclic amp phosphodiesterase.all cyclic amp-utilizing mutants had the growth and fermentation properties of cyclic amp receptor protein (crp) mutants, and some lacked cyclic amp binding activity in vitro. the genetic defect in each such mutant w ... | 1976 | 179973 |
| the effect of bacterial infections on ketone concentrations in rat liver and blood and on free fatty acid concentrations in rat blood. | the concentrations of cytoplasmic lactate and pyruvate and the nad+/nadh ratio and the concentrations of mitochondrial acetoacetate, beta-hydroxybutyrate, and the nad+/nadh ratio were determined in normal, fed, and fasted rats, and in rats infected with streptococcus pneumoniae, francisella tularensis, and salmonella typhimurium. the various infections were found to have little or no effect on the cytoplasmic parameters. in normal rats, fasting caused a marked increase in blood and hepatic keton ... | 1976 | 181658 |
| simultaneous selection of mutants in gluconeogenesis and nucleoside catabolism in salmonella typhimurium. | penicillin selection in minimal thymidine medium, used to select mutants in deoxynucleoside catabolism, also yields a high percentage (37%) of mutants in fructose diphosphatase. the expression of the deo regulon is retarded in the mutants defective in the glyconeogenic pathway. | 1976 | 182268 |
| non-specific immunity after local immunization. | the most important advantage of local immunization is the non-specific effect. the active protection test in mice shows an immunity against oral infection with virulent salmonella typhimurium bacteria after oral immunization with heterologous inactivated enterobacteria. we observed the same non-specific protection in a viral model. after oral immunization with inactivated s. typhimurium bacteria, the mice are protected against oral infection with a virulent parapoliomyelitis virus. in the phagoc ... | 1976 | 182583 |
| action of polymyxin b on bacterial membranes. binding capacities for polymyxin b of inner and outer membranes isolated from salmonella typhimurium g30. | radioactive mono-n-acetyl-14c-polymyxin b or natural polymyxin b are within 60 s absorbed by isolated inner (cytoplasmic) and outer membranes from salmonella typhimuriumg30. the sigmoidal binding isotherms indicate saturation of inner and outer membranes with approximately 30 and 60 nmoles polymyxin b bound per mg membrane, respectively. based on the known content of these membranes in lipopolysaccharide, phosphatidylglycerol, cardiolipin and phosphatidylethanolamine, a calculation of the theor ... | 1976 | 183617 |
| methionine-repressible homoserine dehydrogenase of serratia marcescens: purification and properties. | serratia marcescens sa-3 possesses two homoserine dehydrogenases and neither has any aspartokinase activity unlike the case of escherichia coli enzymes. the two enzymes have been separated. one of them is active with either nad+ or nadp+ and has been purified about 180-fold to homogeneity. this enzyme is completely repressed by the presence of 1 mm methionine or homoserine in the growth medium, but its activity is unaffected by any amino acid of the aspartate family either singly or together. in ... | 1976 | 184374 |
| leakage of periplasmic enzymes from lipopolysaccharide-defective mutants of salmonella typhimurium. | mutants of salmonella typhimurium with defects in the heptose region of the lipopolysaccharide (lps) molecule (heptose-deficient, chemotype re) leak periplasmic enzymes (acid phosphatase (ec 3.1.3.2), cyclic phosphodiesterase, ribonuclease i (ec 3.1.4.22), and phosphoglucose isomerase (ec 5.3.1.9) (pgi is at least partially periplasmic in e. coli and s. typhimurium; see below)) and do not leak an internal enzyme (glucose-6-phosphate dehydrogenase) into the growth medium. the extent of this leaka ... | 1976 | 184900 |
| arginine-sensitive phenotype of mutations in pyra of salmonella typhimurium: role of ornithine carbamyltransferase in the assembly of mutant carbamylphosphate synthetase. | the phenotype of certain mutations in pyra, the gene encoding carbamylphosphate synthetase (cpsase), is expressed only in the presence od exogenous arginine. in unsupplemented media, synthesis of carbamylphosphate and growth was almost normal; in arginine-containing media, synthesis of carbamylphosphate stopped, as did growth, as a consequence of starvation for pyrimidine. genetic and biochemical evidence suggests that arginine exerts this inhibition by repressing the synthesis of ornithine carb ... | 1976 | 185193 |
| isolation and partial characterization of an argr mutant of salmonella typhimurium. | an arginine regulatory mutant (i.e., mutated in the argr gene) has been isolated from a strain of salmonella typhimurium lt2. the argr mutant was found to excrete arginine into the growth medium with glycerol but not glucose as carbon source. constitutive synthesis of arginine biosynthetic enzymes was observed. whereas previous results (a. t. abd-e1-a1 and j. l. ingraham, abstr. annu. meet. am. soc. microbiol. 1975, k169, p. 175) have shown constitutive synthesis of carbamyl phosphate synthetase ... | 1976 | 185197 |
| effect of polymyxin on the outer membrane of salmonella typhimurium: freeze-fracture studies. | polymyxin-caused projections on the cell surface of salmonella typhimurium were seen as depressions in the outer concave fracture face and as protrusions in the outer convex fracture face, indicating participation of both leaflets of the outer membrane in these projections. | 1976 | 185199 |
| ultrastructure of lipopolysaccharides of yersinia enterocolitica, salmonella typhimurium and escherichia coli. | the fine structure of isolated lipopolysaccharides (lps) from the rough and smooth form of an yersinia enterocolitica strain (ye 75 r/ye 75 s) and from smooth forms of salmonella typhimurium (s 1010) and escherichia coli (essen) were examined electron-microscopically by negative staining. partial denaturation of lps in tris-buffer with acid and/or polymyxin b treatment revealed a common structure of strandlike lps. electron-microscopically, lps-strands were found to consist of two identical sub- ... | 1976 | 185850 |
| response of mouse liver glycogen cycle enzymes to endotoxin treatment. | the present study was undertaken to characterize endotoxin-induced changes in carbohydrate metabolism and more specifically, to determine the contribution of glycogenolysis to the loss of liver glycogen. female icr mice, fasted overnight, were injected with a median lethal dose (ld50, 9 mg/kg) of endotoxin extracted from salmonella typhimurium strain sr-11. glycogen synthase and glycogen phosphorylase activities were measured at 0.5 and 6 h after treatment. endotoxin treatment did not alter tota ... | 1976 | 185914 |
| fosfomycin resistance: selection method for internal and extended deletions of the phosphoenolpyruvate:sugar phosphotransferase genes of salmonella typhimurium. | selection for resistance to the antibiotic fosfomycin (fos; l-cis 1,2-epoxypropylphosphonic acid, a structural analogue of phosphoenolpyruvate) was used to isolate mutants carrying internal and extended deletions of varying lengths within the ptshi operon of salmonella typhimurium. strains carrying "tight" ptsi point mutations and all mutants in which some or all of the ptsi gene was deleted were fos resistant. in contrast, strains carrying ptsh point mutations were sensitive to fos. resistance ... | 1976 | 186449 |
| hepatocarcinogenicity of estragole (1-allyl-4-methoxybenzene) and 1'-hydroxyestragole in the mouse and mutagenicity of 1'-acetoxyestragole in bacteria. | approximately 20% of a dose of estragole, a naturally occurring flavoring agent, was excreted in the urine of outbred male cd -1 mice as a conjuage (presumably the glucuronide) of 1'-hydroxyestragole, estragole and its 1'-hydroxy metabolite caused significant increases in the incidences of hepatocellular carcinomas in male cd-1 mice that received the compounds by sc injection at 1-22 days of age. estragole induced hepatocellular carcinomas by 15 months in 23 and 39% of the mice that received tot ... | 1976 | 187802 |