| antagonistic effect of extremely oxygen-sensitive clostridia from the microflora of conventional mice and of escherichia coli against shigella flexneri in the digestive tract of gnotobiotic mice. | two extremely oxygen-sensitive strains of clostridium sp., designated clostridium e and p, were obtained from digestive microflora of conventional mice and found to constitute a barrier against shigella flexneri sf-2 when associated in vivo with escherichia coli k-12. these and other simplified fractions of the conventional microflora were demonstrated to have an effect comparable to that of the total flora. when k-12 and clostridium e were established in gnotobiotic mice before the introduction ... | 1977 | 330410 |
| blastogenic transformation by lipopolysaccharide of blood leukocytes from immunized but not normal cattle. | escherichia coli lipopolysaccharide produced blastogenic transformation in whole-blood leukocytes from heifers that had been infected and immunized with campylobacter fetus, but not in cells from control animals. this suggests that lipopolysaccharide dose not function as a b-cell mitogen in cattle and that its stimulation of cells from immunized animals occurred through another mechanism. | 1977 | 330414 |
| penicillin g or ampicillin for oral treatment of canine urinary tract infections. | penicillin g or ampicillin was administered orally to 144 dogs with urinary tract infections. the daily dosage of penicillin g ranged from 110,000 to 165,000 u/kg (50,000-75,000 u/lb), and the dosage of ampicillin varied from 77 to 110 mg/kg (35-50 mg/lb). the daily dose of each antibiotic was divided into 3 or 4 doses and given at approximately 8- or 6-hour intervals for 10 to 14 days. response to treatment, based on results of urine culture, varied from no response for infections caused by pse ... | 1977 | 330479 |
| clinical evaluation of pivmecillinam in acute simple cystitis: a comparative study with amoxycillin by a randomized double-blind technique. | the comparative efficacy of pivmecillinam and amoxycillin in 243 patients with acute simple cystitis was determined in a randomized double-blind trial. pivmecillinam was found to be significantly more effective on both clinical and bacteriological grounds. the superiority of pivmecillinam was primarily due to its efficacy in infections due to ampicillin resistant escherichia coli. fewer side effects were reported in patients who received pivmecillinam. | 1977 | 330481 |
| propionate-induced synthesis of odd-chain-length fatty acids by escherichia coli. | exogenous propionate is incorporated in vivo by escherichia coli as a primer to produce lipids with fatty acids of odd chain lengths. this provides a method for the specific labeling of the three terminal carbons in the fatty acyl chains of phospholipids. | 1977 | 330493 |
| fine-structure mapping of the fira gene, a locus involved in the phenotypic expression of rifampin resistance in escherichia. | the fira (ts)200 mutation not only eliminates the resistance to rifampin of certain genetically resistant strains, but, moreover, renders ribonucleic acid synthesis thermolabile. the fira gene has been mapped by p1 tranduction and is located extremely close to the structural gene for deoxyribonucleic acid polymerase iii at 4 min on the escherichia coli linkage map. | 1977 | 330494 |
| genetic characterization of an escherichia coli mutant altered in the structure of murein lipoprotein. | mutants defective in the structure, biosynthesis, and assembly of murein lipoprotein have been isolated. one of these mutants has been shown to synthesize a structurally altered lipoprotein. the biochemical features of the mutant lipoprotein (lipid deficiency, dimer formation, and a reduced, bound form of lipoprotein) could be attributed to a single mutation (or closely linked mutations) located at 36.4 min of the escherichia coli map. we propose that this mutant is altered in the structural gen ... | 1977 | 330496 |
| isolation and characterization of specialized lambda transducing bacteriophage carrying the metbjf methionine gene cluster. | secondary attachment site lysogens of deltaatt(lambda)deltappc-argecbh strains of escherichia coli with lambdaci857 integrated into the bfe gene (88 min) were isolated. of 20 such lysogens examined, 2 produce lysates with transducing phage containing the metbjf gene cluster (87 min). reintroduction of the ppc-argecbh chromosome segment (which lies between the bfe and met genes) into these strains virtually abolishes the production of met transducing phage. all of the phage examined have lost ess ... | 1977 | 330497 |
| genetic analysis of escherichia coli k-12 region i flagellar mutants. | flagellar mutants in escherichia coli region i were obtained by selection for resistance to the flagellotropic phage chi. f' elements carrying this region of the e. coli genome were then constructed. stable merodiploid strains with a flagellar defect on the exogenate and another on the endogenote were prepared. these merodiploids yielded information on the complementation behavior of mutations in this region. region i was shown to include at least six cistrons, flav, flak, flal, flam, flas, and ... | 1977 | 330498 |
| intracellular localization of the superoxide dismutases of escherichia coli: a reevaluation. | all of the superoxide dismutase isozymes of escherichia coli have been shown to occur in the cell matrix, and none have been found in the periplasm. this was the case with both e. coli b and e. coli k-12, whether grown on a low phosphate medium or on a trypticase soy-yeast extract medium. alkaline phosphatase was used as a marker of the periplasm; adenosine deaminase and glucose 6-phosphate dehydrogenase were used as matrix markers, and consistent results were obtained by osmotic shock, spheropl ... | 1977 | 330499 |
| major proteins of the escherichia coli outer cell envelope membrane as bacteriophage receptors. | three escherichia coli phages, tuia, tuib, and tuii, were isolated from local sewage. we present evidence that they use the major outer membrane proteins ia, ib, and ii, respectively, as receptors. in all cases the proteins, under the experimental conditions used, required lipopolysaccharide to exhibit their receptor activity. for proteins ia and ii, an approximately two- to eightfold molar excess of lipopolysaccharide (based on one diglucosamine unit) was necessary to reach maximal receptor act ... | 1977 | 330500 |
| isolation, genetic analysis, and characterization of escherichia coli mutants with defects in the lacy gene. | five hundred thirty-five lacy mutants were isolated from an escherichia coli strain carrying the lactose operon on an f' factor, either without mutagenesis or after mutagenesis with 2-aminopurine or n-methyl-n'-nitro-n-nitrosoguanidine. crosses against 48 independently isolated deletions ending in the lacy gene divided the gene into 36 deletion groups. suppressibility studies with 7 nonsense suppressor strains classified 276 mutants as nonsense mutants and 78 as missense (or nonsuppressible) mut ... | 1977 | 330501 |
| glutamate transport driven by an electrochemical gradient of sodium ions in escherichia coli. | the role of na+ in glutamate transport was studied in escherichia coli b, strain 29-78, which possesses a very high activity of glutamate transport (l. frank and i. hopkins, j. bacteriol., 1969). energy-depleted cells were exposed to radioactive glutamate in the presence of a sodium gradient, a membrane potential, or both. one hundred- to 200-fold accumulation of the amino acid was attained in the presence of both electrical and chemical driving forces for the sodium ion. somewhat lower accumula ... | 1977 | 330502 |
| threonyl-transfer ribonucleic acid synthetase from escherichia coli: subunit structure and genetic analysis of the structural gene by means of a mutated enzyme and of a specialized transducing lambda bacteriophage. | threonyl-transfer ribonucleic acid synthetase (thrrs) has been purified from a strain of escherichia coli that shows a ninefold overproduction of this enzyme. determination of the molecular weight of the purified, native enzyme by gel chromatography and by polyacrylamide gel electrophoresis at different gel concentrations yielded apparent molecular weight values of 150,000 and 161,000, respectively. polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate yields a single prot ... | 1977 | 330505 |
| relationship between cell coiling and motility of spirochetes in viscous environments. | the lowest viscosity that stops translational motility of cells (minimum immobilizing viscosity [miv] was determined for various spirochetes. the viscous agent used was polyvinylpyrrolidone, the miv for either spirochaeta halophila p1 or spirochaeta aurantia j4t was approximately 1,000 centipoise (cp), and for leptospira interrogans (biflexa) b16 the miv was greater than 500 cp. in comparison, the miv for the flagellated bacteria escherichia coli and spirillum serpens was 60 cp. miv values for t ... | 1977 | 330506 |
| relationship between messenger ribonucleic acid and enzyme levels specified by the leucine operon of escherichia coli k-12. | the levels of leucine-forming enzymes in escherichia coli k-12 varied over a several thousand-fold range, depending upon conditions of growth. the highest levels were achieved by growing auxotrophs in a chemostat under conditions of leucine limitation. under such conditions, enzyme levels were increased 45- to 90-fold relative to cells grown in minimal medium containing leucine (the latter values arbitrarily called 1). leucine operon-specific messenger ribonucleic acid levels were elevated to ab ... | 1977 | 330509 |
| properties of proteins produced after damage to deoxyribonucleic acid of escherichia coli. | large amounts of extra proteins, x (in the envelope fraction) and x' (in the cytoplasmic fraction) were detected by sds-polyacrylamide gel electrophoresis when dna of escherichia coli was damaged. these two proteins had the same apparent molecular weight (appproximately 40,000) and were produced under identical conditions, including requirement for the reca" and lexa+ genotype. sucrose density gradient centrifugation revealed that protein x' consisted of relatively large and heterogeneous aggre ... | 1977 | 330510 |
| studies on the allosteric properties of mutationally altered phosphoenolpyruvate carboxylases of escherichia coli. discrimination of allosteric sites. | | 1977 | 330511 |
| transport of sugars and amino acids in bacteria. xviii. properties of an isoleucine carrier in the cytoplasmic membrane vesicles of escherichia coli. | the properties of the carrier for isoleucine in escherichia coli were studied using cytoplasmic membrane vesicles (im vesicles) prepared by the method of yamato, anraku, and hirosawa (j. biochem. 77, 705 (1975)). the im vesicles exhibited respiration-dependent isoleucine transport activity which was more than 30-fold higher than that of "kaback vesicles" prepared by our hand from the same strains of e. coli k12. the isoleucine carrier activity of im vesicles was inhibited by norleucine but not b ... | 1977 | 330512 |
| strain specificity of outer membrane proteins in escherichia coli. | outer membrane proteins of various strains of escherichia coli were compared using three different systems of sodium dodecyl sulfate (sds)-polyacrylamide gel electrophoresis. the outer membranes of e. coli k-12, e. coli b, and e. coli j-5 had distinctive protein compositions. as regards proteins which interact with peptidoglycan, e. coli k-12 contained o-8 and o-9, while e. coli b possessed one protein which migrated to the position of o-9. although e. coli j-5 possessed two such proteins, o-8' ... | 1977 | 330513 |
| lipoprotein-bearing peptidoglycan sacculus as a preferred site for the in vitro assembly of membrane from dissociated components of outer membrane of escherichia coli k-12. | | 1977 | 330517 |
| studies on bacterial chemotaxis. i. separation of proteins from cell envelope of escherichia coli. | radioactive proteins from escherichia coli cell envelope fraction were separated by two-dimensional polyacrylamide gel electrophoresis. electrophoresis was carried out under several sets of conditions, and autoradiographs were obtained. many of the proteins were separated at well-defined positions with good reproducibility. some of the proteins moved relative to these stationary proteins depending at least two factors, i.e. the amount of proteins applied in the first dimension and the electric c ... | 1977 | 330519 |
| regulation of escherichia coli ornithine transcarbamylase by orotate. | ornithine transcarbamylase from escherichia coli, strain w, exhibits negative cooperativity with respect to ornithine, and the enzymatic activity is further regulated by orotate. the effect of orotate on ornithine transcarbamylase is dependent not only upon the carbamylphosphate concentration, but also upon the concentration of ornithine. at high concentrations of carbamylphosphate (10 mm), a conversion from negative cooperativity to positive cooperativity is observed with 10 mm orotate. at 1 mm ... | 1977 | 330520 |
| escherichia coli protein x is the reca gene product. | escherichia coli protein x is known to be made in large amounts following dna damage or inhibition of dna replication. we have shown that it is identical to the reca gene product by partial proteolytic digestion of the radiochemically pure proteins and analysis by electrophoresis on polyacrylamide-sodium dodecyl sulfate gels. | 1977 | 330525 |
| micrococcus luteus correndonucleases. ii. mechanism of action of two endonucleases specific for dna containing pyrimidine dimers. | py pyrimidine dimers py correndonucleases i and ii from micrococcus luteus act exclusively on thymine-thymine, cytosine-cytosine, and thymine-cytosine cyclobutyl dimers in dna, catalyzing incision 5' to the damage and generating 3'-hydroxyl and 5'-phosphoryl termini. both enzymes initiate excision of pyrimidine dimers in vitro by correxonucleases and dna polymerase i. the respective incised dnas, however, differ in their ability to act as substrate for phage t4 polynucleotide ligase or bacterial ... | 1977 | 330526 |
| identification of udp-glucose as an intermediate in the biosynthesis of the membrane-derived oligosaccharides of escherichia coli. | the membrane-derived oligosaccharides of escherichia coli constitute a closely related family of oligosaccharides containing approximately 9 glucose units variously substituted with sn-glycero-1-phosphate and phosphoethanolamine residues derived from the head groups of membrane phospholipids, and also with succinate in o-ester linkage (kennedy, e.p., rumley, m.k., schulman, h., and van golder, l.m.g. (1976) j. biol. chem. 251, 4208-4213). studies with mutant strains defective in the synthesis of ... | 1977 | 330527 |
| pseudouridine-deficient transfer rnas from escherichia coli b and their use as substrates for pseudouridine synthetase. | transfer rnas isolated from escherichia coli b grown in the presence of 2-thiouracil are deficient in pseudouridine. much of this deficiency is from the t psi c region, which has only about 50% of its normal pseudouridine content. the other modified nucleoside from this region, ribothymidine, is reduced by only about 10%. studies showed that 2-thiouracil is incoproated into the rna of e. coli during growth in the presence of the analog. this incorporation appears to result from the replacement o ... | 1977 | 330528 |
| role of anticodon bases in aminoacylation of escherichia coli methionine transfer rnas. | | 1977 | 330530 |
| dna polymerase iii holoenzyme of escherichia coli. purification and resolution into subunits. | dna polymerase iii holoenzyme has been purified from escherichia coli hms-83, using, as an assay, the conversion of coliphage g4 single-stranded dna to the duplex replicative form. the holoenzyme consists of at least four different subunits: alpha, beta, gamma, and delta of 140,000, 40,000, 52,000, and 32,000 daltons, respectively. the alpha subunit is dna polymerase iii, the dnae gene product. the holoenzyme has been resolved by phosphocellulose chromatography into an alpha - gamma - delta comp ... | 1977 | 330531 |
| organization of the yeast ribosomal rna gene cluster via cloning and restriction analysis. | the restriction endonuclease ecor1 cleaves saccharomyces cerevisiae dna, which codes for ribosomal rna (rrna), into seven fragments, a second restriction endonuclease, hindiii, cleaves the same yeast ribosomal dna into two fragments. these two restriction enzymes each yield dna segments that total about 5.9 megadaltons. the "repeat unit" of the yeast genes coding for rrna is thus about 5.9 megadaltons or about 9000 base pairs long. the two hindiii-cleaved dna fragments as well as one of the ecor ... | 1977 | 330533 |
| tryptophan synthase of escherichia coli. removal of pyridoxal 5'-phosphate and separation of the alpha and beta2 subunits. | | 1977 | 330534 |
| analysis of the structure of t4 bacteriophage-modified valyl-trna synthetase by limited proteolysis and isoelectric focusing. | the new form of valyl-trna synthetase (ec 6.1.1.9) that appears immediately after infection of escherichia coli with bacteriophage t4 was purified and subjected to mild proteolysis using five different proteases. the inactivation of aminoacylation activity was both more extensive and rapid than that obtained with valyl-trna synthetase purified from uninfected e. coli. the addition of bulk trna from e. coli b protected the phage-specific form of valyl-trna synthetase from proteolysis, but atp and ... | 1977 | 330535 |
| effect of cysteine modification on dihydrofolate reductase from a methotrexate-resistant strain of escherichia coli b. identification of modified residues. | | 1977 | 330537 |
| purification and characterization of polynucleotide phosphorylase from escherichia coli. probe for the analysis of 3' sequences of rna. | a simple procedure for purifying polynucleotide phosphorylase from escherichia coli cells by means of affinity chromatography on an rna-sepharose column is described. the purified enzyme preparation has a specific activity 3500-fold that of the crude extract and is essentially homogeneous, as determined by ultracentrifugation, polyacrylamide gel electrophoresis under denaturing conditions, isoelectric focusing and serological assays. it is virtually free of nuclease contamination, a property whi ... | 1977 | 330538 |
| influence of modified nucleosides in e. coli transfer ribonucleic acids on chromatographic mobilities of transfer rna. | | 1977 | 330553 |
| use of omega-aminohexyl-sepharose in the fractionation of escherichia coli b aminoacyl-trna synthetases. | the usefulness of aminohexyl-sepharose in purification of e. coli b aminoacyl-trna synthetases is presented. the purification factors for 14 synthetases lie in the range 3- to 94-fold and the recoveries of the enzymatic activity were 30-80%, depending on the enzyme. | 1977 | 330554 |
| esculin hydrolysis by enterobacteriaceae. | literature reports disagree concerning esculin hydrolysis in the family enterobacteriaceae. a total of 2,490 strains of the family were investigated for esculin hydrolysis by two methods, the esculin spot test and the pathotec incubation strip, which measures constitutive enzyme, and five growth-supporting methods, which determine both constitutive and inducible enzymes. the five growth-supporting media studied were: vaughn-levine, the standard esculin hydrolysis medium (p. r. edwards and w. h. ... | 1977 | 330558 |
| relationship of k1 antigen to biotype in clinical isolates of escherichia coli. | two hundred and ninety-four isolates of escherichia coli, including 105 from blood cultures, 94 from stools of hospital inpatients, and 96 from rectal cultures of healthy young adults, were biotyped by using the api-20e system and tested for the presence of k1 antigen. the overall frequency of k1 strains was 14.2% and was similar among the three sources. forty-eight biotypes were observed, but two-thirds of all isolates, including two-thirds of the k1 strains, belonged to only five biotypes. amo ... | 1977 | 330559 |
| growth of cell wall-defective variants of escherichia coli: comparison of aerobic and anaerobic induction frequencies. | a method for quantitating the conversion of escherichia coli to colony-forming, cell wall-defective (cwd) bacteria has been developed. the induction frequency, i.e., the percentage of the population recovered as cwd colonies was determined for 20 randomly selected clinical isolates of e. coli under aerobic and anaerobic incubation conditions. penicillin (1,000 u/ml) was the inducing agent. the 20 strains segregated into three groups. group i organisms produced cwd colonies with high frequency bo ... | 1977 | 330562 |
| relative enterotoxigenicity of coliform bacteria. | the enterotoxigenicity of 12 strains of coliform bacteria (enterobacter cloacae, klebsiella pneumoniae, and escherichia coli) isolated from the gastrointestinal (gi) tract of persons with either acute diarrhea or tropical sprue and of 13 strains of the same species isolated from urine (gu) cultures was determined. fractions of heat-labile (lt) and heat-stable (st) toxins of each strain were separated by ultrafiltration, and the effect of graded concentrations (range, 100 microgram-10 pg/ml) on w ... | 1977 | 330767 |
| gastroenteritis in children: a two-year review in manitoba. i. etiology. | during two years, 1,217 children hospitalized with gastroenteritis at the children's centre in winnipeg, manitoba, canada were studied. bacterial pathogens were present in 25% of these children: enteropathogenic escherichia coli in 120, shigella in 139, salmonella in 24, and multiple pathogens in 18. rotavirus was detected in 54 (11%) of 472 patients examined. rotavirus and enteropathogenic e. coli were the most common pathogens in infants, and shigella was the most common in older children. bac ... | 1977 | 330769 |
| virulence factors of enterotoxigenic escherichia coli. | further evidence for the role of enterotoxigenic escherichia coli as an etiologic agent of diarrhea is presented. a retrospective study of 71 cases of diarrhea in mexican children demonstrated that greater than 40% of them harbored e. coli that produced heat-labile and/or heat-stable enterotoxin. the antigenic surface-associated colonization factor of e. coli strain h-10407 has been further characterized: this pilus-like antigen is produced under conditions of growth that repress the production ... | 1977 | 330772 |
| antigens of escherichia coli, human immune response, and the pathogenesis of urinary tract infections. | acute pyelonephritis (but not cystitis or "asymptomatic" bacteriuria) due to escherichia coli induces serum antibodies to o-but rarely to k-antigens, especially not to the most common antigen, k1. locally produced secretory iga and igg antibodies to o-and k-antigens appear in urine during most infections. the e. coli in urine of patients with asymptomatic bacteriuria are different from those in patients with acute pyelonephritis and cystitis and undergo continuous changes, presumably caused by t ... | 1977 | 330773 |
| antibody to cell wall glycolipid of gram-negative bacteria: induction of immunity to bacteremia and endotoxemia. | antiserum to the core glycolipid of gram-negative bacteria was prepared by immunization of rabbits with vaccine composed of killed cells of the uridine diphosphate galactose-deficient mutant (j5) of escherichia coli o:111. antiserum to j5 not only prevented death of animals from endotoxin but also prevented the local and generalized shwartzman reactions. antiserum to endotoxin also prevented renal cortical necrosis and disseminated intravascular coagulation during the evolution of the generalize ... | 1977 | 330776 |
| the infant rat as a model of bacterial meningitis. | the pathogenesis of bacterial meningitis was studied in infant rats. intranasal intoculation of greater than 10(3) haemophilus influenzae type b resulted in an incidence of bacteremia that was directly related to the size of hte challenge inoculum. the temporal and quantitative relationship of bacteremia to meningitis indicated that bacteria spread to the meninges by the hematogenous route and that the magnitude of bacteremia was a primary determinant in the development of meningitis. in a spara ... | 1977 | 330777 |
| neonatal meningitis due of escherichia coli k1. | human neonates are uniquely susceptible to serious infections due to escherichia coli. investigation of the serotypes of e. coli isolated from neonates with meningitis revealed that greater than 80% of the isolates possessed the capsular polysaccharide antigen designated k1. cultures of stool from healthy infants, children, and adults have shown that k1 organisms are commonly found in individuals of all ages. studies of mother-infant pairs have demonstrated transmission of k1 strains from mothe ... | 1977 | 330780 |
| intestinal colonization and adhesion by enteroxigenic escherichia coli: ultrastructural observations on adherence to ileal epithelium of the pig. | colonization of pig ileum by enterotoxigenic escherichia coli that were enteropathogenic for pigs but that lacked k88 antigen (k88-) resulted in morphological characteristics similar to those reported for k88+ strains. strains of enterotoxigenic e. coli from three different k88-serotypes adhered to the villous epithelium. in sections examined by transmission electron microscopy, adherent bacteria were separated from each other and from epithelial microvilli by peribacterial electron-lucent regio ... | 1977 | 330781 |
| genetic control of lymphocyte activation: lack of response to low doses of concanavalin a in lipopolysaccharide-nonresponder mice. | c3h/hej mice do not respond to the polyclonal b-cell activator lipopolysaccharide (lps) from escherichia coli; this was first described by sultzer who observed that mice of this strain did not respond to an intraperitoneal (i.p.) injection of lps as measured by the accumulation of leukocytes in the peritoneal cavity. neither were c3h/hej mice as susceptible to lps toxcitiy (1). it was later reported that lps-induced mitogenesis (2,3), adjuvanticity (4), and the appearance of ia antigens on b lym ... | 1977 | 330792 |
| the mechanism of action of nitro-heterocyclic antimicrobial drugs. primary target of 1-methyl-2-nitro-5-vinylimidazole is dna. | the antimicrobial drug 1-methyl-2-nitro-5-vinylimidazole (mev) preferentially blocked dna synthesis, was mutagenic and induced coliphage lambda in escherichia coli. the antibacterial effects of mev are the consequences of repairable damage to dna, as shown by hypersensitivity of reca and uvr strains to mev and related drugs, stimulation by mev of dna turnover which was dependent on the product of the uvra gene, and the presence of cross-links in dna from mev-treated bacteria. | 1977 | 330809 |
| the mechanism of action of nitro-heterocyclic antimicrobial drugs. metabolic activation by micro-organisms. | although the target of the antimicrobial drug 1-methyl-2-nitro-5-vinylimidazole (mev) has been shown to be dna (goldstein et al., 1977) the drug was ineffective in cell-free systems because it was not activated. both the rate of metabolic activation of mev and its antibacterial activity were increased when bacteria were grown in limiting oxygen. mutants of escherichia coli which were conditionally resistant to nitroimidazoles and nitrofurans were defective in drug activation. the activities of t ... | 1977 | 330810 |
| regulation of glucosamine utilization in staphylococcus aureus and escherichia coli. | glucosamine- or n-acetylglucosamine-requiring mutants of staphylococcus aureus 209p and escherichia coli k12, which lack glucosamine-6-phosphate synthetase [2-amino-2-deoxy-d-glucose-6-phosphate ketol-isomerase (amino-transferring); ec 5.3.1.19], were isolated. growth of these mutants on glucosamine was inhibited by glucose, but growth on n-acetylglucosamine was not. addition of glucose to mutant cultures growing exponentially on glucosamine inhibited growth and caused death of bacteria, though ... | 1977 | 330812 |
| genetic determinants of the synthesis of the polysaccharide capsular antigen k27(a) of escherichia coli. | most of the his+ hybrids from crosses between the escherichia coli donor hfr45(o8:k27) and different e. coli o9 recipients expressed the donor o8 antigen specificity and produced the capsular antigen k27. therefore these hybrids must have inherited the his-linked donor rfb region determining the synthesis of o8- specific polysaccharides as well as his-linked genes involved in k27 antigen synthesis. in the living state these hybrids were inagglutinable in o8 antiserum like the donor cells. howeve ... | 1977 | 330813 |
| morphological distinction between different h serotypes of escherichia coli. | the structure of the flagellar filaments of 50 escherichia coli strains, each with a different h antigen, was examined. although the flagella within each strain were structurally identical, there was variability in flagellar surface pattern between strains with differrent h antigens. investigation of additional strains confirmed that flagella structure was the same in all strains having the same h antigen. in three pairs of strains with cross-reacting h antigens, the antigenic relatedness was as ... | 1977 | 330817 |
| comparison of the flagellins from different flagellar morphotypes of escherichia coli. | the molecular weights of the flagellins of 13 strains of escherichia coli, each with a different h antigen, were estimated using polyacrylamide gel electrophoresis. in each case only one major polypeptide was demonstrated, although some strains possessed apparently sheathed flagella. considerable differences in the molecular weight of flagellin accompanied the previously described structural differences between flagella from strains with different h antigens. the relationship between flagellar d ... | 1977 | 330818 |
| pyrimidine dimer excision and dna degradation during liquid holding recovery in ultraviolet-irradiated escherichia coli k12 uvr+ rec. | the survival of ultraviolet-irradiated escherichia coli k12 uvr+re was increased by post-irradiation incubation in phosphate buffer. during this incubation both dimer excision and dna breakdown were inhibited. it is suggested that the bacteria coped with the remaining dimers in a manner which did not involve excision. | 1977 | 330820 |
| dna degradation in wild-type and repair-deficient strains of salmonella typhimurium exposed to ultraviolet light of photodynamic treatment. | five mutants of salmonella typhimurium strain lt2 trp di (colei)+, initiallly detected because they released little or no colicin when tested on solid medium, proved to be sensitive to ultraviotet light (u.v.). further testing indicated that one of the mutants was deficient in genetic recombination and was probably a reca-type mutant, while three of the others were deficient in dna polymerase activity and appeared to be typical pola mutants. the fifth mutant was less sensitive than the others to ... | 1977 | 330821 |
| spontaneous and ultraviolet-induced mutation in escherichia coli: interaction between plasmid and tif-i mutator effects. | | 1977 | 330822 |
| the effect of a drug-resistance factor on recombination and repair of dna in escherichia coli k12. | the presence in recipient strains of escherichia coli k12 of the plasmid r46 greatly reduced the yield of recombinants from crosses with several hfr strains and virtually abolished the formation of recombinants by pi transduction without, however, significantly affecting the transfer of the f prime from a strain carrying fgal. the r46 plasmid had paradoxical effects on mutability: it appeared to enhance the yield of mutants following irradiation with ultraviolet ligh but it reduced the number of ... | 1977 | 330823 |
| on the accuracy of identification of k1 e. coli. | | 1977 | 330833 |
| prophylactic antibiotics for women undergoing vaginal hysterectomy. | a triple-blind prospective study of women undergoing vaginal hysterectomy was conducted to compare cefazolin, cephaloridine and no antibiotic, both cefazolin and cephaloridine were given preoperatively, whereas only cephaloridine was given postoperatively. one gram of cefazolin given intramuscularly on call to the operation room was found to be a safe and effective antibiotic for prophylaxis against febrile morbidity. the proper utilization of prophylactic antibiotics seems to be in the immediat ... | 1977 | 330851 |
| biochemical typing of urinary escherichia coli strains by means of the api 20 e enterobacteriaceae system. | with the api 20 e enterobacteriaceae system of biochemical testing, a biotype, coded numerically, was determined for each of 574 strains of escherichia coli isolated from patients with urinary tract infection. the serotypes of the strains were also determined. fifty-five different biotypes were identified, two accounting together for 42% of the strains examined and seven others each accounting for between 8.4 and 1.9%. there was little correlation between biotype and serotype. fifty pairs of str ... | 1977 | 330859 |
| characteristics of antibiotic-resistant escherichia coli in the rectum of healthy school-children. | during a 3-year period, 771 rectal swabs were taken from abacteriuric school-children. out of 709 e. coli strains, each isolated from one faecal specimen, 102 were found to be resistant to one or more antibacterial agents, and 607 to be fully sensitive. another 204 resistant strains were found by selection for antibiotic resistance. the antibiotic-sensitive and the resistant strains were found to be two somewhat different populations, distinguished by a different distribution of o antigen types. ... | 1977 | 330860 |
| sequence arrangements of the escherichia coli chromosome and of putative insertion sequences, as revealed by electron microscopic heteroduplex studies. | | 1977 | 330866 |
| in vitro packaging of uv radiation-damaged dna from bacteriophage t7. | when dna from bacteriophage t7 is irradiated with uv light, the efficiency with which this dna can be packaged in vitro to form viable phage particles is reduced. a comparison between irradiated dna packaged in vitro and irradiated intact phage particles shows almost identical survival as a function of uv dose when escherichia coli wild type or pola or uvra mutants are used as the host. although uvra mutants perform less host cell reactivation, the pola strains are identical with wild type in th ... | 1977 | 330877 |
| bacteriophage t4 virion dihydrofolate reductase: approaches to quantitation and assessment of function. | this paper is concerned with the physiological role(s) of t4 phage-coded dihydrofolate reductase, which functions both in dna precursor metabolism and as a virion protein. (i) we have detected enzyme activity in noninfectious particles produced under restrictive conditions by gene 11 mutants. this supports the conclusion of kozloff et al. (j. virol. 16:1401-1408, 1975) that the protein lies in the baseplate, covered by the gene 11 protein. (ii) we have obtained further evidence for virion dihydr ... | 1977 | 330880 |
| localization of single-chain interruptions in bacteriophage t5 dna i. electron microscopic studies. | bacteriophage t5 dna was examined in an electron microscope after limited digestion with exonuclease iii from escherichia coli. the effect of the exonuclease treatment was to convert each naturally occurring single-chain interruption in t5 dna into a short segment of single-stranded dna. the locations of these segments were determined for t5st(+) dna, t5st(0) dna, and fragments of t5st(0) dna generated by ecori restriction endonuclease. the results indicate that single-chain interruptions occurr ... | 1977 | 330881 |
| dna modification of bacteriophage mu-1 requires both host and bacteriophage functions. | it was previously shown that resistance of phage mu-1 to several restriction enzymes is due to a modification function (called mom) encoded by the phage. more recent studies emphasized that modification of mu requires not only an active mom function, but also an active dam function supplied by the escherichia coli host. | 1977 | 330882 |
| gram-negative sepsis with acute renal failure. occurrence from acute glomerulonephritis. | acute intrinsic renal failure occurred in an adult patient with escherichia coli septicemia. the clinical course did not include any of the circumstances usually present when acute renal failure complicates gram-negative sepsis. a renal biopsy showed acute proliferative glomerulonephritis. there was no evidence to support other known causes of acute parenchymal renal failure, such as poststreptococcal glomerulonephritis, subacute bacterial endocarditis, or vasculitis. the patient recovered compl ... | 1977 | 330892 |
| [escherichia coli enterotoxons]. | | 1977 | 330900 |
| characterization of a periplasmic protein related to sn-glycerol-3-phosphate transport in escherichia coli. | | 1977 | 330954 |
| [effect of osmotic pressure on the process of rna penetration into escherichia coli spheroplasts and on the effectiveness of their transfection by phage rna]. | | 1977 | 331030 |
| [energy dependence of the process of phage rna penetration into escherichia coli spheroplasts]. | | 1977 | 331031 |
| special o:k:h serotypes among enterotoxigenic e. coli strains from diarrhea in adults and children. occurrence of the cf (colonization factor) antigen and of hemagglutinating abilities. | o:h serotypes previously found to be prevalent among a number of toxigenic strains from several geographic areas were examined for polysaccharide k antigen type. members of each o:h serotype had the same type of k antigen and were found to be characterized by a certain fermentation pattern. some o:h serotypes had no k antigen. the serofermentative types defined were: 06:k15:h16, 08:k40:h9, 015:h11, 025:k7:h42, 025:k98:h-, 078:h11, 078:h12, and 0149:h10. some strains of the last-mentioned serotyp ... | 1977 | 331065 |
| formation of recombinant dna of bacteriophage lambda by reca function of escherichia coli without duplication, transcription, translation, and maturation. | genetic recombination of phage lambda dna mediated by rec function of escherichia coli was studied in the absence of duplication, transcription, translation, and maturation. cells were jointly infected with double amber mutants, lambda d-f-i and lambda s-r-, and incubated in the presence of chloramphenicol and rifampin. the am+ recombinant dna molecules formed within the cell were detected by in vitro packaging as viable recombinant phages. this system was used to measure the recombination activ ... | 1977 | 331071 |
| prophage induction and cell division in e. coli. v. dominance and complementation analysis in partial diploids with pleiotropic mutations (tif, reca, zab and lexb) at the reca locus. | | 1977 | 331073 |
| linkage of 5s rna and 16s+23s rna genes on the e. coli chromosome. | episomes carrying limited regions of the chromosome where 5s rna genes have previously been located are described. the dna purified from each of these episomes contains one gene per molecule for each of the three ribosomal rna species as shown by hybridization experiments. | 1977 | 331075 |
| the fira gene, a locus involved in the expression of rifampicin resistance in escherichia coli. i. characterisation of lambdafira transducing phages constructed in vitro. | the fira200 mutation of e. coli not only renders rna synthesis thermosensitive but also eliminates the high-level resistance to rifampicin associated with certain mutations in the beta subunit of the rna polymerase. a priori, the fira gene is likely to code for an essential component of the transcription apparatus. the isolation is reported of transducing phages for the fira gene, constructed in vitro by fusing fragments of the e. coli chromosomes into a lambdoid bacteriophage. such phages carry ... | 1977 | 331078 |
| ribosomal abnormality in reca mutants of escherichia coli. | the tif-1 mutation has been shown to affect protein synthesis in vitro by increasing translational ambiguity (ephrati-elizur, luther-davies and hayes, 1976). it is demonstrated here that some reca mutations confer similar abnormality. by comparing suitable combinations of ribosomes and soluble proteins from reca+ and reca cells the defect is shown to be associated with ribosomes. the reca mutation, which suppresses most phenotype characteristics of the tif-1 mutation (castellazzi, george and but ... | 1977 | 331079 |
| escherichia coli plasmid pbr313 insertion into plant protoplasts and into their nuclei. | cowpea mesophyll protoplasts were shown to bind irreversibly up to 3% input radioactive pbr313 plasmid dna after 15 min of contact. maximum uptake occurred in the presence of 5 mm znso4 and 5 microgram/ml poly-l-ornithine. under these conditions about one half of the tca precipitable radioactivity was associated with the nuclear fraction and behaved as linear plasmid molecules. these could not be chased from the protoplasts upon further incubation with unlabeled plasmid dna. the presence of dono ... | 1977 | 331080 |
| genetics of ribosomal protein methylation in escherichia coli. i. a mutant deficient in methylation of protein l11. | several thousand mutagenized clones of escherichia coli were screened for methyl group incorporation into protein in crude extracts, in order to isolate mutants lacking the full complement of methyl groups in ribosomal proteins. one mutant isolated by this method and designated prm-1 incorporated 6-7 methyl groups per ribosome upon incubation of its ribosomes with a partially purified enzyme preparation from e. coli wild-type. the methyl groups were located exclusively in the 50s particle and fo ... | 1977 | 331082 |
| genetics of ribosomal protein methylation in escherichia coli. ii. a mutant lacking a new type of methylated amino acid, n5-methylglutamine, in protein l3. | the ribosomes of an escherichia coli mutant, designated prm-2, can be methylated in vitro by an enzymatic fraction from wild-type. this enzyme is inactive on the ribosomes from another mutant, prm-1, is reported previously to be methyl group-deficient in protein l11. in vitro methylation of prm-2 ribosomes resulted in the incorporation of about one methyl group per molecule of protein l3. after acid hydrolysis, all the methyl groups were found in a very basic compound which was identified as met ... | 1977 | 331083 |
| arsenate-resistant alkaline phosphatase-constitutive mutants of escherichia coli. | when arsenate-resistant mutants are selected approximately 50 per cent of them are also consitutive for the synthesis of alkaline phosphatase and the pi-binding protein. some of these mutants are linked to ilv (phos- or phot-), other are linked to proc (phor-). one of the mutant strains linked to ilv lost the pi-binding protein (the phos gene product). resistance to arsenate, constitutivty for alkaline phosphatase synthesis and loss of the pi-binding protein occurred pleiotropically by the same ... | 1977 | 331084 |
| conditional lethal mutants of bacteriophage t4 unable to grow on a streptomycin resistant mutant of escherichia coli. | sixteen conditional lethal mutants of bacteriophage t4d have been isolated which grow on escherichia coli cr63 (a su+ streptomycin-sensitive k12 strain) but are restricted by cr/s (a streptomycin-resistant derivative of cr63). these mutants have been given the prefix str. four of these mutants are amber and 12 appear to be missense. eleven of the 12 missense mutants appear to be "pseudo-amber" (i.e. they are restricted by a su- e. coli b strain but not by a su- k12 strain); the other missense mu ... | 1977 | 331100 |
| sepsis due to escherichia coli in neonates with galactosemia. | | 1977 | 331112 |
| natural history of neonatal colonization with group b streptococci. | thirteen percent of the newborns in our study group were colonized with group b streptococci on day 3. this colonization rate appeared constant during the first two weeks of life and then decreased to 5%. of the babies colonized on day 3, 59% and 91% were culture-negative on days 14 and 42, respectively. sixty-five percent of the babies carrying group b streptococci on day 14 acquired this microorganism following discharge (day 3). babies colonized with staphylococci or escherichia coli were fou ... | 1977 | 331224 |
| [possibilities of using indirect hemagglutination tests in the diagnosis of intestinal coli infections by rarely encountered e. coli serotype]. | | 1977 | 331227 |
| physiochemical studies on interactions between dna and rna polymerase. unwinding of the dna helix by escherichia coli rna polymerase. | in a medium containing 10mm tris, ph 8, 10 mm mg++, 50 mm k+ and 10 mm nh4, the binding of an e. coli rna polymerase holoenzyme unwinds the dna helix by about 240 degrees at 37 degrees c. in this medium the total unwinding of the dna increases linearly with the molar ratio of polymerase to dna. the number of binding sites at which unwinding can occur is very large. if the k+ concentration is increased at 200 mm, the enzyme binds to only a limited number of sites, and the bound and free enzyme mo ... | 1977 | 331252 |
| binding of e.coli lac repressor to non-operator dna. | it is shown by melting profile analysis of lac repressor-dna complexes that repressor binds tightly and preferentially (relative to single-stranded dna) to double-stranded non-operator dna. this binding stabilizes the dna against melting and the repressor against thermal denaturation. analysis of the extent of stabilization and the rate of dissociation of repressor from non-operator dna as a function of sodium ion concentration shows, in confirmation of other studies,(3,4) that the binding const ... | 1977 | 331259 |
| a strong ethidium binding site in the acceptor stem of most or all transfer rnas. | e. coli unfractionated trna and trna phe both contain a single strong ethidium binding site. singlet-singlet energy transfer has been used to measure the distance between this site and dansyl hydrazine covalently attached to the 3' end of the trnas. the distance obtained is between 33 and 40 a for both samples. this is completely consistent with results from earlier nmr studies which placed the single, strong ethidium binding site of yeast trnaphe between base pairs 6 and 7 on the aminoacyl stem ... | 1977 | 331262 |
| analogs of methionyl-trna synthetase substrates containing photolabile groups. | three photolabile analogs of substrates of methionyl-trna synthetase were synthesized. in one, the 4-thiouridine at the 8 position of e. coli trnafmet was alkylated with [14c]p-azidobromoacetanilide. in the second, [14c]p-azidobenzoic acid hydrazide was condensed with the 3'-terminal dialdehyde of periodate-oxidized escherichia coli trnafmet. the modified trnas could be purified by chromatography on benzoylated deae-cellulose. the third photolabile compound was [3h]methioninyl-8-azido-adenosine ... | 1977 | 331263 |
| inhibition of transcription of supercoiled pm2 dna by carbodiimide modification. | pm2 superhelican dna (form i), which as been reacted with the single strand specific reagent, n-cyclohexyl-n'-beta-(methylmorpholinium)ethyl carbodiimide (cmc) is more than 95% inhibited in its ability to support transcription with e. coli b rna polymerase in vitro. almost complete inhibition of transcription was achieved after 2 hours of reaction with fi when only 1% of the bases were modified. a large increase in s20,* (from 26.8 s to 33.6 s) of fi dna was observed during the course of reactio ... | 1977 | 331264 |
| rabbit liver trna1val:ii. unusual secondary structure of t psi c stem and loop due to a u54:a60 base pair. | in contrast to all other known trnas, mammalian trna1val contains two adenosines a59 and a60, opposite to u54 and psi 55 in the u psi cg sequence of the t psi c loop, which could form unusual a:u (or a: psi pairs in addition to the five "normal" g:c pairs. in order to measure the number of g:c and a:u (a: psi) pairs in the t psi c stem, we prepared the 30 nucleotide long 3'-terminal fragment of this trna by "m7g-cleavage". from differentiated melting curves and temperature jump experiments it wa ... | 1977 | 331268 |
| interaction of rabbit reticulocyte ribosomes with bacteriophage f1 mrna and of escherichia coli ribosomes with rabbit globin mrna. | we have compared the behavior of a prokaryotic mrna in a eukaryotic ribosome binding system and of a eukaryotic mrna in a prokaryotic ribosome binding system. using (32)p- and (125)i-labeled bacteriophage f1 mrna, we have shown that rabbit reticulocyte 80s ribosomes can protect specific sequences from pancreatic rnase digestion, including those sequences protected by escherichia coli ribosomes. we have also found that e. coli ribosomes fail to protect any region of (125)i-labeled globin mrna. io ... | 1977 | 331312 |
| identification of spacer trna genes in individual ribosomal rna transcription units of escherichia coli. | transfer rna genes ("spacer trna genes") are present in the spacer region between 16s and 23s rrna genes in escherichia coli. we have analyzed spacer trna genes carried by seven rrna operons with different chromosomal locations. six of these were isolated on plasmids and one on a transducing phage. we found that, in addition to the two previously identified genes for trna2glu and trnaiile, there is a spacer trna gene which codes for trnaibala. of the seven rrna operons studied, three had both tr ... | 1977 | 331313 |
| release of escherichia coli dna from membrane complexes by single-strand endonucleases. | treatment of gently prepared lysates of escherichia coli with single-strand-specific endonuclease (si or from mung beans) results in the release of about 90% of the dna from membranes, as determined by the m band technique. the released dna has an average molecular weight of about 1.2 x 10(8). data obtained with endonuclease s1 fit a mathematical model in which substrate sites are at or near membrane attachment sites. data obtained with pancreatic deoxyribonuclease or x-rays fit a model for doub ... | 1977 | 331316 |
| extracellular labeling of nascent polypeptides traversing the membrane of escherichia coli. | to provide direct evidence for the hypothesis that secreted proteins may traverse membranes as growing chains, we labeled spheroplasts of escherichia coli with a reagent (acetyl[35s]methionyl methylphosphate sulfone) that reacts with amino groups but does not cross the membrane. after fractionation, about 6% of the label in the membrane-polysome fraction was found to be attached to the polysomes. this attachment was via peptidyl-trna, as shown by several tests: release of most of the label from ... | 1977 | 331317 |
| mutants of escherichia coli lacking in highly penicillin-sensitive d-alanine carboxypeptidase activity. | mutants of escherichia coli lacking in the highly penicillin-sensitive enzyme activities of d-carboxy-peptidase, transpeptidase, and endopeptidase, and with the concomitant absence of penicillin-binding protein 4 of b.g. spratt and a.b. pardee [(1975) nature 254, 516-517] were isolated. the defect of these mutants is ascribed to the lack of an enzyme, d-alanine carboxypeptidase ib. genetic mapping studies show the mutation (dacb) to be located at 68 min on the e. coli chromosome map. the dacb mu ... | 1977 | 331322 |
| simultaneous deletion of d-alanine carboxypeptidase ib-c and penicillin-binding component iv in a mutant of escherichia coli k12. | mutants of escherichia coli with much decreased activity of d-alanine carboxypeptidase (peptidyl-d alanine hydrolase, ec 3.4.12.11) were found among e. coli k12 extensively mutagenized with nitrosoguanidine treatment by assaying individual colonies for the enzyme activity. one such mutant with only 10-12% residual activity was characterized extensively. the soluble carboxypeptidase activity (corresponding to d-alanine carboxypeptidase ic of tamura t., imae, y. & strominger, j.l. [(1976) j. biol. ... | 1977 | 331323 |
| photoreactivating enzyme from escherichia coli. | | 1977 | 331349 |
| radiation sensitivity of t1 bacteriophage on various host strain mutants of escherichia coli. | | 1977 | 331387 |