| contamination of pig carcasses at two abattoirs by escherichia coli with special reference to o-serotypes and antibiotic resistance. | | 1977 | 323213 |
| methodology for recognition of invasive potential of escherichia coli. | surveillance for dysentery-related invasive potential in bacteria using the sereny keratoconjunctivitis test is restricted by expense, time factor, and necessity for confirmation. primary screening of isolates in a standardized mammalian cell culture system is recommended. bacteria are grown 20 hr in veal infusion, washed, and resuspended in 20% heat-inactivated fetal bovine serum (fbs) supplemented with 0.12% brain heart infusion and 0.1% bile salts. the hela culture is grown 20 hr as a monolay ... | 1977 | 323215 |
| rela gene control of the synthesis of lipid a fatty acyl moieties. | the incorporation of [14c]acetate into the fatty acid moieties of lipid a was measured during amino acid starvation of rel+ and rela strains of escherichia coli k-12. the synthesis of the beta-hydroxymyristate and other fatty acid moieties was inhibited two- to fourfold in rel+ strains, whereas no inhibition was observed in rela strains. the fatty acid compositions of the phospholipids synthesized after amino acid starvation or rel+ and rela strains were also determined. | 1977 | 323219 |
| medium-dependent variation of deoxyribonucleic acid segregation in escherichia coli. | the degree to which deoxyribonucleic acid segregates nonrandomly has been investigated for escherichia coli b/r growing in different media. the degree of nonrandom segregation observed is dependent on the medium, with segregation becoming less random as the growth rate decreases. this indicates that there must be some varying probabilistic component to the segregation process. a probabilistic modification of the pierucci-zuchowski model is proposed as well as a probabilistic model, in which it i ... | 1977 | 323220 |
| regulation of prpp and nucleoside tri and tetraphosphate pools in escherichia coli under conditions of nitrogen starvation. | the ribonucleoside triphosphate, deoxyribonucleoside triphosphate, 3' -diphosphate guanosine 5' -diphosphate (ppgpp), and 5-phosphoribosyl 1-pyrophosphate (prpp) pools in escherichia coli b were determined by thin-layer chromatography during changing conditions to ammonium starvation. the intracellular concentrations of all nucleotides were found to change in a well-defined order several minutes before andy observed change in the optical density of the culture. the levels of purine nucleoside tr ... | 1977 | 323222 |
| role of the 30s ribosomal subunit, initiation factors, and specific ion concentration in barotolerant protein synthesis in pseudomonas bathycetes. | washed (1 m nh4cl) ribosomes from pseudomonas bathycetes, pseudomonas fluorescens, and escherichia coli were tested for their ability to synthesize protein or polypeptide at high pressure when used as such, when recombined with homologous initiation factors, and when recombined with heterologous initiation factors. the responses of natural messenger ribonucleic acid (ms-2)-directed systems to pressure were independent of the source of initiation factors and paralleled those of the washed ribosom ... | 1977 | 323224 |
| metabolic characterization of the viable, residually dividing and nondividing cell classes of recombination-deficient strains of escherichia coli. | the abilities of rec+, recb- recc-, reca-, and reca- recb- rec c- strains to support growth of bacteriophage t4, to take up oxygen, and to maintain cell integrity have been measured. (i) with respect to bacteriophage t4 growth, t4 phage is produced with identical lysis time in single -step growth curves with all strains tested. rec- strains show reduced phage production (fewer infected centers), but the average burst size per infected center is the same for all strains tested. some rec- cells ar ... | 1977 | 323225 |
| method for the isolation of escherichia coli mutants with enhanced recombination between chromosomal duplications. | a method is described for the isolation of escherichia coli mutants that show increased recombination between a pair of chromosomal duplications. these "hyper-rec" mutants display a variety of secondary phenotypes. i have isolated a large number of hyper-rec mutants and found them useful in screening for mutants that accumulate labeled dna fragments after short pulses with [3h]thymidine. the mutants so recovered include ones that are defective in deoxyribonucleic acid ligase, deoxyribonucleic ac ... | 1977 | 323226 |
| repair of hydrogen peroxide-induced single-strand breaks in escherichia coli deoxyribonucleic acid. | near-ultraviolet (300 to 400 nm) irradiation of l-tryptophan yielded h2o2 (a toxic photoproduct) that was selectively lethal for rec and pola1 escherichia coli mutants. h2o2 treatment of cells resulted in the induction of single-strand deoxyribonucleic acid breaks. these breaks were repaired to only a small extent in pola1, reca recb, and reca mutants, but were efficiently repaired in wild-type strains. we conclude that h2o2 deoxyribonucleic acid lesions require both the pola+ and reca+ pathways ... | 1977 | 323227 |
| physiological regulation of a decontrolled lac operon. | the expression of the lac operon was studied under a variety of growth conditions in induced and in constitutive cells of escherichia coli that carried different catabolite-insensitive lac promoters. use of such "decontrolled" lac operons permitted a study of the expression of an operon that was presumably subject only to passive control. since the use of toluenized cells was demonstrated not to be completely reliable, all enzyme assays were performed on sonic supernatant fluids. the cells conta ... | 1977 | 323228 |
| suppression of an escherichia coli dnaa mutation by the integrated r factor r100.1: generation of small plasmids after integration. | we have observed that integration of the r plasmid r100.1 into the chromosome of escherichia coli is associated with the formation of small, covalently closed circular elements. contour length measurements, partial denaturation mapping, and analysis of the deoxyribonucleic acid fragments produced by digestion of one of these, plc1, with the restriction endonuclease ecori indicate that it is the r-determinant element of r100.1. | 1977 | 323231 |
| cell surface-localized alkaline phosphatase of escherichia coli as visualized by reaction product deposition and ferritin-labeled antibodies. | when cells of a wild-type eschericia coli o8 strain bearing a complete lipopolysaccharide were incubated for alkaline phosphatase reaction product and examined by electron microscopy, the depostion of lead salts was to be observed primarily within the periplasmic space. a similar treatment of cells derived from this strain, which bears a highly abbreviated lipopolysaccharide, showed a mixed cell surface and periplasmic localization of reaction product, suggesting a surface association of a porti ... | 1977 | 323232 |
| immunocytological investigation of protein synthesis in escherichia coli. | ferritin-conjugated specific antibodies have been used to localize beta-galactosidase and both the monomer and active dimer of alkaline phosphatase in frozen thin sections of cells of escherichia coli o8 strain f515. the even distribution of the ferritin marker throughout cells that had been induced for beta-galactosidase synthesis, frozen, sectioned, and exposed to ferritin-anti-beta-galactosidase conjugate showed that this enzyme was present throughout the cytoplasm of these cells. frozen thin ... | 1977 | 323233 |
| degradation of escherichia coli beta-galactosidase fragments in protease-deficient mutants of salmonella typhimurium. | the degradation rates of several mutationally generated fragments of escherichia coli beta-galactosidase were determined in wild-type strains of salmonella typhimurium and in mutant salmonella strains lacking several proteases and peptidases. three termination fragments (produced by lacz545, lacz521, and laczx90) and one internal reinitiation (restart) fragment [laczpi(1)] are degraded in wild-type salmonella strains at the same rates observed in wild-type escherichia coli strains. mutations tha ... | 1977 | 323234 |
| isolation and characterization of plaque-forming lambdadnaz+ transducing bacteriophages. | the escherichia coli dnaz gene, a deoxyribonucleic acid (dna) polymerization gene, is located 1.2 min counterclockwise from pure, at approximately min 10.5 on the e. coli map. from a lysogen with lamdaci857 integrated at a secondary attachment site near pure, transducing phages (lambdadnas+) that transduced a dnazts (lambda+) recipient to temperature insensitivity (ts+) were discovered. three different plaque-forming transducing phages were isolated from seven primary heterogenotes. genetic test ... | 1977 | 323235 |
| escherichia coli transport mutants lacking binding protein and other components of the branched-chain amino acid transport systems. | further evidence on the role of binding proteins in branched-chain amino acid transport in escherichia coli was obtained by selecting mutants with altered expression of the binding proteins. the mutator phage mu was used to induce e. coli l-valine-resistant mutants defective in branched-chain amino acid transport. by making use of mild selective conditions and strain backgrounds with derepressed high-affinity, binding protein-mediated transport systems, we were able to isolate a new class of tra ... | 1977 | 323236 |
| biochemical and regulatory properties of escherichia coli k-12 hist mutants. | escherichia coli k-12 hist mutants were isolated, and their properties were studied. these mutants are derepressed for the histidine operon, map close to the purf locus at about 49.5 min on the e. coli linkage map, and lack pseudouridylate synthetase activity. the defect in this enzyme leads to the absence of pseudouridines in the anticodon loop of several transfer ribonucleic acid species, as evidenced by the altered elution profile on reversed-phase chromatography and resistance to amino acid ... | 1977 | 323237 |
| mapping of the aspartate and aromatic amino acid aminotransferase genes tyrb and aspc. | co-transduction experiments using p1-mediated reciprocal and three-factor crosses have been used to map two mutations affecting the aspartate and aromatic amino acid aminotransferases of escherichia coli. tyrb-, which inactivates the tyrosine-repressible component of these activities is co-transducible with meta and malb; the gene order is meta-malb-tyrb. aspc-, which inactivates the nonrepressible aminotransferase with high activity for aspartate, maps between and is co-transducible with serc a ... | 1977 | 323238 |
| isolation and characterization of escherichia coli phase variants and mutants deficient in type 1 pilus production. | type 1 pili of escherichia coli are the prototype of the somatic class of pili found on many strains of bacteria. as a first step in the genetic analysis of type 1 piliation, an extensive series of nonpiliated derivatives of e. coli k-12 strain aw405, was characterized to produce attached or free pili when examined in the antiserum or appeared to produce attached or free pili when examined in the electron microscope. the derivatives fell into two classes; phase variants and mutants. phase varian ... | 1977 | 323240 |
| genetic complementation analysis of escherichia coli type 1 somatic pilus mutants. | a genetic complementation analysis of 75 stable nonpiliated mutants of a type 1 piliated strain of escherichia coli k-12, aw405, was performed. strains containing pairs of pil mutations were constructed by the infectious transfer of an f101 plasmid containing one pil mutation into e. coli k-12 aw 405 containing another pil mutation. the presence or absence of type 1 pili on the merodiploid strains was determined by agglutination with type 1 pilus antiserum. all 75 mutants fell into one of four c ... | 1977 | 323241 |
| further characterization of the recipient ability of escherichia coli k-12 bacteriophage-resistant mutants. | we extended the study of escherichia coli mutants defective in conjugation and showed that the mutants with altered lipopolysaccharide, which are defective as recipients with f-like donors, are also defective with the i-like plasmid r64-11. however, the extent of reduction in recipient ability for i-like donors does not correlate either with the effect on recipient ability for f-like donors or with the degree of alteration to the lipopolysaccharide. | 1977 | 323242 |
| escherichia coli k-12 mutant with alternate requirements for vitamin b6 or branched-chain amino acids and lacking transaminase c activity. | an escherichia coli k-12 auxotrophic derivative that grows if supplemented with pyridoxine, isoleucine, leucine, or alanine is described. | 1977 | 323243 |
| unstable mutations that relieve catabolite repression of tryptophanase synthesis by escherichia coli. | from strains of escherichia coli that carry deletions of the trp region, five different mutants were isolated that were capable of synthesizing tryptophanase at unusually high rates in conditions of severe catabolite repression. notwithstanding the comparative insensitivity to catabolite repression, the rates of tryptophanase synthesis in the mutants were greatly diminished by the introduction of a defective gene for adenyl cyclase. each of the mutants segregated variants of the parental type. t ... | 1977 | 323244 |
| initiation and termination of deoxyribonucleic acid replication in bacteria after a stepwise increase in the velocity of replication. | the theoretical relations between replication, initiation, termination, and deoxyribonucleic acid (dna) accumulation were derived for experiments in which the length of the time required for the replication of the bacterial chromosome (c period) can be varied. this theory enables one to determine absolute values of the c period from kinetics of dna accumulation after a "stepup" with thymine-requiring bacteria that are subjected to a sudden increase in the exogenous thymine concentration. applica ... | 1977 | 323245 |
| uridine and cytidine transport in escherichia coli b and transport-deficient mutants. | three mutants of escherichia coli b which are defective in components of the transport system for uridine and uracil were isolated and utilized to study the mechanism of uridine transport. mutant u- was isolated from a culture resistant to 77 micronm 5-fluorouracil. mutant u-ur-, isolated from a culture of mutant u-, is resistant to 770 micronm 5-fluorouracil and 750 micronm adenosine. mutant nuc- is resistant to 80 micronm showdomycin and has been reported previously. the characteristics of uri ... | 1977 | 323246 |
| selective inhibition of phix rfii compared with fd rfii dna synthesis in vitro. ii. resolution of discrimination reaction into multiple steps. | in the presence of rna polymerase, rnase h, discriminatory factors alpha and beta, escherichia coli binding protein, dna elongation factor i, dna elongation factor ii preparation, dna polymerase iii, and atp, utp, gtp, ctp, datp, dttp, dgtp, and dctp, fd viral dna can be quantitatively converted to rfii containing a unique gap in the linear minus strand. this gap, mapped with the aid of restriction endonucleases hinii and hpaii, is located within fragment hpa-h of the fd genome. the discriminati ... | 1977 | 323248 |
| adriamycin interactions with t4 dna polymerase. two modes of template-mediated inhibition. | we examined the effect of adriamycin on kinetics of dna synthesis catalyzed by dna polymerase purified from bacteriophage t4-infected escherichia coli. two distinct modes of enzyme inhibition occur: uncompetitive and competitive at "low" and "high" drug:dna nucleotide molar ratios, respectively. competitive inhibition is not observed unless an unblocked amino group is present on the sugar (daunosamine) moiety. a model is proposed to relate the enzyme inhibition kinetics to intercalative and ioni ... | 1977 | 323251 |
| evidence for single mechanism for aminoacyl-trna synthetases including aminoacyl adenylates as intermediates. | the rate of transfer of amino acid from enzyme-bound aminoacyl adenylate to trna has been compared with the rate of esterification of free amino acid. the approach of lövgren et al. (lövgren, t. n. e., heinonen, j., and loftfield, r. b. (1975) j. biol. chem. 250, 3854-3860) was used, with 14c in the aminoacyl adenylate and 3h in the free amino acid and with both the lysine and isoleucine systems of escherichia coli. in both systems kinetic analyses show more rapid transfer from the preformed enz ... | 1977 | 323252 |
| intracellular dna-protein complexes from bacteriophage t4-infected cells isolated by a rapid two-step procedure. characterization and identification of the protein components. | a simple technique has been developed for isolating intracellular dna and its bound proteins from uninfected and phage-infected bacteria. this technique, which utilizes aqueous salt concentrations in the physiological range, is based upon the fact that dna exists in normal cell lysates in a stiff random coil conformation, and has an unusually large excluded volume to mass ratio. such stiff coils display a unique combination of low sedimentation coefficient and large stokes radius, enabling them ... | 1977 | 323253 |
| an aspartate transcarbamylase lacking catalytic subunit interactions. study of conformational changes by ultraviolet absorbance and circular dichroism spectroscopy. | a modified form of aspartate transcarbamylase is synthesized by escherichia coli in the presence of 2-thiouracil which does not exhibit homotropic cooperative interactions between active sites yet retains heterotropic cooperative interactions due to nucleotide binding. the conformational changes induced in the modified enzyme by the binding of different ligands (substrates, substrate analogs, a transition state analog, and nucleotide effectors) were studied using ultraviolet absorbance and circu ... | 1977 | 323258 |
| multiple pathways for primary processing of ribosomal rna in escherichia coli. | a comparison of isogenic rnase iii+ and rnase iii- strains of escherichia coli shows that although both synthesize precursor and mature 16 s and 23 s ribosomal rnas, the transient rrna species of the rnase iii- strain differ from those of the rnase iii+ strain. the rnase iii+ strain synthesizes p16 and p23 rrna, whereas the rnase iii- strain produces unstable 17 s, 18 s, "p23," 25 s and 30 s rna molecules. the 30 s rna, which is a primary transcript of the ribosomal rna gene cluster, does not co ... | 1977 | 323260 |
| immunospecific retention of oligonucleotides possessing n6-methyladenosine and 7-methylguanosine. | antibodies specific for n6-methyladenosine (m6a) and for 7-methylguanosine (m7g) were immobilized on sepharose and the resulting immunoadsorbents tested for their ability to retain specific oligonucleotides possessing the corresponding antigenic haptens (i.e. m6a and m7g). results obtained with oligonucleotides derived from ribonuclease t1 digests of escherichia coli trna (previously labeled with [methyl-3h]methionine) indicated that each immunoadsorbent quantitatively and exclusively retained t ... | 1977 | 323262 |
| site-specific membrane particle arrays in magnesium-depleted escherichia coli. | the ultrastructure and polypeptide composition of a novel membrane junction in magnesium-starved escherichia coli are described in this report. freeze-fracture replicas reveal the junction as a site-specific membrane particle array with four fracture faces. each junction consists of a cell membrane, a midline zone and a coupled membrane. membrane particles associated with the junction extend from the hydrophobic region of the cell membrane across the hydrophilic midline zone and into the hydroph ... | 1977 | 323269 |
| influence of a deficiency of the second component of complement on the bactericidal activity of neutrophils in vitro. | serum from three patients with a complete, selective deficiency of the second component of complement (c2) did not promote optimal killing of staphylococcus aureus, 502a by neutrophilic polymorphonuclear leukocytes (pmn) in vitro. the addition of c2 reagent or the presence of heat-stable opsonin in the c2-deficient serum corrected the defective killing of s. aureus that was observed with patient or control pmn. pmn from the patients or control subjects killed bacteria with equal efficiency under ... | 1977 | 323290 |
| colonization of porcine small intestine by escherichia coli: colonization and adhesion factors of pig enteropathogens that lack k88. | the colonizing and adhesive attributes of enterotoxigenic acapsular and/or nonpiliated mutants from k88-negative enteropathogenic escherichia coli strains were compared with their capsulated and piliated parents (parents were piliated when grown in vitro and in vivo). acapsular, nonpiliated mutants from three different colonizing strains of enteropathogenic e. coli lost their ability to colonize the ileum of newborn pigs. acapsular, piliated and capsular, nonpiliated mutants were derived from on ... | 1977 | 323375 |
| significance of antibody-coated bacteria in urinary sediment in experimental pyelonephritis. | the sequential appearance of antibody-coated bacteria in urinary sediment was followed in experimental pyelonephritis produced with escherichia coli o6:k13:h1. it was possible to determine against which antigen of the organism this antibody was directed. antibody-coated bacteria appeared by day 11 of infection, a time which coincided with the synthesis of local (intrarenal) antibody. bacteria coated with antibody more than three days after serum antibody but four days before urinary antibody app ... | 1977 | 323377 |
| characterization of the chinese hamster ovary cell assay for the enterotoxins of vibrio cholerae and escherichia coli and for specific antisera, and toxoid. | the morphologic change in chinese hamster ovary (cho) cells that is associated with increased intracellular concentrations of adenosine 3':5'-cyclic phosphate (cyclic amp) provided a highly sensitive assay for the heat-liable enterotoxins of vibrio cholerae and escherichia coli. the similarity between the responses of cho cells and those of intestinal mucosa to enterotoxins was demonstrated by the inhibition of these effects by the ganglioside galactosyl-n-acetylgalactosaminyl [sialosyl] lactosy ... | 1977 | 323378 |
| clinical and laboratory assessment of the pathogenicity of serotyped enteropathogenic escherichia coli. | only one of 167 separate isolates of enteropathogenic escherichia coli (eec) was shown to produce enterotoxin, and none of the 167 isolates were invasive. clinical features of 123 hospitalized children with eec were compared with those of 917 infants with nonbacterial gastroenteritis and 145 infants infected with shigella. the average duration of diarrhea (five or more stools per day) in hospitalized children with eec, nonbacterial gastroenteritis, shigella flexneri, and shigella sonnei was 4.6, ... | 1977 | 323379 |
| monitoring enzyme synthesis as a means of studying peptide transport and utilization in escherichia coli. | a new method has been developed for measuring peptide transport in aminoacid auxotrophs of escherichia coli by following induction of beta-galactosidase. appearance of the enzyme was determined after addition of inducer and peptides to amino-acid starved bacteria. for a given number of lysine equivalents, the rate and the extent of enzyme synthesis were the same for lysine and lysyl peptides; similar results were found for glycine and glycl peptides. saturation constants for peptide transport we ... | 1977 | 323413 |
| expression of klebsiella pneumoniae nitrogen fixation genes in nitrate reductase mutants of escherichia coli. | nitrate reductase (nar) a, b and e mutants of escherichia coli with plasmids carrying klebsiella pneumoniae nitrogen fixation (nif) genes reduced acetylene independently of added molybdate, but nar d mutants showed pleiotropic dependence on the concentration of added molybdate for expression of both nar and nif. no complementation of nar mutations by nif occurred; nitrite but not nitrate repressed nif in nar hosts. derepression of nif occurred in molybdenum-deficient nar d (nif) strains since ni ... | 1977 | 323414 |
| a novel pleiotropic mutation in escherichia coli k12 which affects transduction, transformation and rates of mutation. | a mutant strain of escherichia coli k12, r2721, has been shown to differ from its parent strain, s491, in four associated phenotypic characters as a result of a single mutation. this strain did not give recombinants with dna transduced by bacteriophage pi or bacteriophage mu, nor transformats after exposure to r factor dna: lysates of bacteriophage pi grown on this strain did not appear to contain any transducing particles when tested on normal recipients. moreover, the reversion rates, both spo ... | 1977 | 323415 |
| uptake and utilization of vitamin b6 and its phosphate esters by escherichia coli. | escherichia coli kg980, a vitamin b6 auxotroph derived from e. coli k12, utilized the three unphosphorylated forms of vitamin b6, more or less effectively, for growth, but did not utilize the three phosphate forms at concentrations ranging from 10(-7) to 10(-5) m in the minimum medium of davis and mingioli. the bacterium, however, utilized the phosphate forms, although less effectively than the unphosphorylated forms, in the phosphate starving medium of garen and levinthal which is known to dere ... | 1977 | 323431 |
| enteropathogenic serotypes of e. coli. | | 1977 | 323444 |
| breast feeding and incidence of e. coli infections in newborn nurseries. | | 1977 | 323445 |
| "enteropathogenic serotypes" of escherichia coli which really are not. | | 1977 | 323447 |
| thymidylate synthetase inhibitors. synthesis of n-substituted 5-aminomethyl-2'-deoxyuridine 5'-phosphates. | a series of substituted 5-aminomethyl-2'-deoxyuridines was synthesized as analogues of 5-thymidylyltetrahydrofolic acid, a proposed intermediate in the thymidylate synthetase catalyzed reaction. 1-(3,5-di-o-p-toluoyl-2-deoxy-beta-d-ribofuranosyl)-5-chloromethyluracil (3) was treated with the appropriate amine to give the ester protected 5-aminomethyl nucleoside. removal of the ester groups was accomplished with anhydrous potassium carbonate in methanol to afford the free beta-nucleoside. in this ... | 1977 | 323484 |
| a protein factor associated with serum resistance in escherichia coli. | immunogel-diffusion studies showed that 60 degree c licl extracts of the smooth serum-resistant mutant escherichia coli strain 17 contained greater amounts of a protein antigen than did extracts of the parent strain lp729. an extract of strain 17 was fractionated on sepharose 4b and the protein antigen was found as the only detectable antigen in a number of fractions; sodium dodecyl sulphate-polyacrylamide gel electrophoresis indicated that these fractions contained one major polypeptide band wi ... | 1977 | 323489 |
| enzymatic unwinding of dna. iii. mode of action of escherichia coli dna unwinding enzyme. | | 1977 | 323494 |
| nucleotide sequence changes produced by mutations in the lac promoter of escherichia coli. | | 1977 | 323498 |
| rel-dependent methionine requirement in revertants of a methionyl-transfer rna synthetase mutant of escherichia coli. | | 1977 | 323499 |
| occurrence of methylated amino acids as n-termini of proteins from escherichia coli ribosomes. | | 1977 | 323502 |
| membrane fluidity and chemotaxis: effects of temperature and membrane lipid composition on the swimming behavior of salmonella typhimurium and escherichia coli. | | 1977 | 323503 |
| inhibition of bacteriophage m13 and phix174 duplex dna replication and single-strand synthesis in temperature-sensitive dnaz mutants of escherichia coli. | a functional dnaz product, known to be essential for host dna polymerization and for the synthesis of m13 and phix174 parental replicative-form (rf) dna, is required also for rf replication and single-strand synthesis by both of these phages. all three stages of m13 and phix174dna replication (parental rf formation, rf replication, and single-strand synthesis) are inhibited in dnazts mutants at elevated temperatures. in addition, the thermolabile step in m13 parental rf formation appears to occu ... | 1977 | 323515 |
| neonatal meningitis and circumcision. | this paper presents four cases of fulminating neonatal sepsis with meningitis. in each infant, there was evidence of an infected circumcision wound. two infants had escherichia coli and two had group b haemolytic streptococcus cultured from the cerebrospinal fluid. one infant died. the risk of introducing infection through iatrogenic portals of entry is a definite problem in the neonate. circumcision is an unnecessary routine procedure, which puts the infant at risk. | 1977 | 323660 |
| the structure of animal mitochondrial dna (base composition, pyrimidine clusters, character of methylation). | base composition, content of pyrimidine isopliths and the degree of methylation of mitochondrial dna (mtdna) and nuclear dna (ndna) from various vertebrates and protozoon crithidia oncopelti have been studied. mtdnas from mammals (ox, rat) do not differ in fact in the gc content from the respective ndna. the gc content in mtdna from fishes (sheat fish) and birds (duck, chicken) is 1.5-2.5 mole % higher than in the respective ndna. kinetoplast dna (kdna) from crithidia oncopelti (gc = 42.9 mole % ... | 1977 | 323687 |
| the frameshift mutability of pola1 and reca1 derivatives of mutator strains of escherichia coli. | | 1977 | 323701 |
| epidemiologic assessment of the relevance of the so-called enteropathogenic serogroups of escherichia coli in diarrhea. | | 1977 | 323706 |
| adherence of escherichia coli to human mucosal cells mediated by mannose receptors. | | 1977 | 323718 |
| nature of recombinants produced by the recbc and the recf pathways in escherichia coli. | | 1977 | 323726 |
| gap filling during postreplication repair of dna in recombination deficient escherichia coli. | | 1977 | 323728 |
| fever produced in the rat by intracerebral e. coli endotoxin. | e. coli endotoxin introduced into the brain ventricles or into various brain areas raises the body temperature of conscious rats. endotoxin-sensitive sites were found within the anterior hypothalamus and the lower brainstem. the increase in temperature (delta t) after microinjection of endotoxin into the anterior hypothalamic nucleus was dose-dependent. endotoxin injected into the ventricles produced monophasic hyperthermia, but microinjections into the anterior hypothalamus produced monophasic ... | 1977 | 323816 |
| fever in rats after intravenous e. coli endotoxin administration. | in conscious unrestrained rats, at an ambient temperature of 22 degrees c, oesophageal temperature was measured and temperature effect of single and repeated intravenous injection of e. coli endotoxin was examined. the first injection of endotoxin in a dose of 10.0 mug/rat did not change the rat body temperature. the second injection of this dose in the same animals repeated after 48 h produced fever. with following injections the fevers observed were less pronounced. the absence of fever after ... | 1977 | 323817 |
| a bacteriophage system for screening and study of biologically active polycyclic aromatic hydrocarbons and related compounds. | the usefulness of bacterial viruses for detecting substances that are potentially carcinogenic is reexamined as a model system for screening biologically active polycyclic aromatic hydrocarbons. a modification of the original assay procedure allows one to distinguish between aromatics that can modify the biological activity of infectious nucleic acids directly and those polycyclic aromatic hydrocarbons that require metabolic activation by escherichia coli enzymes. the effect of chemical modifica ... | 1977 | 323848 |
| biochemical characterization of a mutant lipoprotein of escherichia coli. | a lipoprotein mutant of e. coli k-12 has been characterized. the mutant lipoprotein was found to differ from the wild-type lipoprotein in the following respects: (i) it is present in an appreciable amount in the soluble fraction (275,000 x g supernatant); (ii) it lacks the covalently-linked diglyceride; (iii) it contains an unmodified cysteine which can be carboxymethylated in vitro; (iv) it undergoes dimerization and the dimer can be converted into monomeric form by reduction with 2-mercaptoeth ... | 1977 | 323849 |
| differential utilization of leucyl-trnas by escherichia coli. | the utilization of the isoaccepting species of leucyl-trna in protein synthesis has been examined in e. coli. two minor leucyl-trna species, isoacceptors trna3leu and trna4leu, are the predominant species found bound to ribosomes during exponential growth in minimal medium. in rich medium, an increased proportion of trna1leu is found bound to ribosomes. one species, trna5leu, is always absent from ribosomes. in a mutant strain in which normal trna3leu and trna5leu are reduced or absent, trna1leu ... | 1977 | 323850 |
| rotational relaxation of 70s ribosomes by a depolarization method using triplet probes. | rotational relaxation on the microsecond time scale has been followed by a depolarization technique using the properties of the long-lived triplet state of covalently bound labels. two triplet probes, which efficiently bind to ribosomal proteins, are described. the rotational correlation time of 70s ribosomes of escherichia coli has been measured. the average hydrodynamic radius of the functionally active 70s particle in solution has been estimated to 147 a. a concentration dependence of the cor ... | 1977 | 323851 |
| on the process of cellular division in escherichia coli: a mutant of e. coli lacking a murein-lipoprotein. | a mutant of e. coli lacking a specific outer membrane lipoprotein was found. both the free and the bound form have been lost in this mutant. no material that cross-reacted with antiserum against lipoprotein was detected by the ouchterlony test. the mutant was defective in producing mrna active for lipoprotein synthesis. the mutation leading to the loss of lipoprotein synthesis, referred to as lpo, seems to have arisen during production of an f'. the map position of lpo was at 36.5 min on the e. ... | 1977 | 323852 |
| synthesis and processing of an escherichia coli alkaline phosphatase precursor in vitro. | alkaline phosphatase [orthophosphoric-monoester phosphohydrolase (alkaline optimum), ec 3.1.3.1] of e. coli was synthesized in a cell-free system, and the size of the direct translation product was analyzed. the product has a higher molecular weight than the mature alkaline phosphatase found in the periplasm. the direct translation product can be processed to the mature size by an e. coli membrane fraction; the processing activity copurifies with the outer-membrane fraction. the presumed precurs ... | 1977 | 323853 |
| ribosome structure: localization of n6,n6-dimethyladenosine by electron microscopy of a ribosome-antibody complex. | antibodies to the minor nucleoside n6,n6-dimethyladenosine have been used to map a unique location of the nucleoside in the small subunit of the escherichia coli ribosome. antibodies were induced in rabbits by a nucleoside-bovine albumin conjugate and shown to be highly specific for the dimethyladenosine hapten. the antibodies were shown to interact with 30s ribosomal subunits from strain pr7, but not with subunits from its mutant strain tpr201, which is resistant to kasugamycin and lacks the tw ... | 1977 | 323854 |
| the amino acid sequence of beta-galactosidase of escherichia coli. | the amino acid sequence of beta-galactosidase was determined. the protein contains 1021 amino acid residues in a single polypeptide chain. the subunit molecular weight calculated from the sequence is 116,248. the sequence determination, carried out mainly by conventional methods, was aided by complementation tests, by the use of termination mutant strains, and by a new immunochemical method. the five residue sequence thr-pro-his-pro-ala appears twice within the polypeptide chain, but no other st ... | 1977 | 323855 |
| hydrogen-bonded protons in the tertiary structure of yeast trnaphe in solution. | temperature-dependent lowfield proton magnetic resonance spectra of yeast trnaphe were recorded between 10 and 15 parts per million. seven resonances of hydrogen-bonded protons disappeared reversibly under two sets of conditions where the selective broadening of tertiary structure resonances were predicted by temperature jump experiments. the seven resonances were assigned to the seven tertiary hydrogen bonds expected between 10 and 15 parts per million from the crystal structure of yeast trnaph ... | 1977 | 323858 |
| an escherichia coli mutant with a temperature-sensitive function affecting bacteriophage qbeta rna replication. | we report the isolation of e. coli mutant capable of supporting replication of bacteriophage qbeta at 33 degrees, but not at 40 degrees. coliphages f2, r23, fd, and yamma formed plaques on mutant cells at both temperatures. temperature-shift experiments showed that bacteriophage q beta replication was blocked in the mutant within the first 20-30 min of infection. the defect did not prevent translation of the qbeta polymerase gene or assembly of catalytically active qbeta replicase molecules. in ... | 1977 | 323859 |
| [assembly of e coli outer membrane (author's transl)]. | | 1977 | 323922 |
| the predisposition to infection following hemorrhagic shock. | subsequent life threatening gram-negative infection in patients successfully resuscitated from hemorrhagic shock is becoming increasingly common. following hemorrhagic shock and resuscitation, sprague-dawley rats were given escherichia coli intraperitoneally to simulate the clinical setting in which peritoneal contamination and hypovolemic shock occur concurrently. a sublethal dosage of bacteria resulted in a 100 per cent mortality. this suggests that hemorrhagic shock, even when treated promptl ... | 1977 | 324005 |
| [clinico-immunobiological indices in chronic e. coli pyelonephritis]. | | 1977 | 324013 |
| role of urothelial surface mucoprotein in intrinsic bladder defense. | to implicate further the surface mucoprotein as the factor responsible for preventing bacterial attachment to the bladder mucosa, rabbit urothelium was severely disrupted and allowed to regenerate for varying periods of time. quantitative measurements of the attachment of 14c-labeled escherichia coli were correlated with the histologic presence of the surface mucoprotein. control levels of bacterial attachment were observed only when the pas-positive layer had regenerated, further supporting the ... | 1977 | 324090 |
| prophylactic use of hyperimmune serum in experimental colisepticaemia in calves. | evidence is presented to demonstrate the efficacy of an intravenously administered polyvalent hyperimmune serum prepared from bovine serum, in the prevention of experimental colisepticaemia produced by oral challenge with e coli o78: k80(b) in colostrum deprived calves. it is suggested that the protection afforded by this hyperimmune serum is due to high levels of specific antibody demonstrable in the serum of calves post treatment and that protection is given in this instance by antibodies cont ... | 1977 | 324111 |
| [bistability of pyruvate production by e. coli ml30 in continuous culture]. | the pyruvate production of e. coli ml30 in continuous cultures was investigated. in a glucose mineralsalt medium with ammonium as the limiting substrate two stable stationary states (bistability) of pyruvate concentration were obtained. the bistability was limited to dilution rates lower than 0.3 h-1 and connected with a decrease of the yield coefficient (y glc) from approximately 0.45 to approximately 0.1. | 1977 | 324146 |
| [increasing the non-specific resistance of animals to pathogenic e. coli with preparations of rna]. | yeast rna and sodium nucleinate considerably increased the nonsusceptibility of mice to pathogenic escherichia and typhoid salmonellae. ineffective single nucleonate doses created an intense resistance in repeated use; prolonged application was not accompanied by the appearance of tolerance to the preparation. the principal mechanism of the induced phenomenon consisted in the intensification of the bacterial elimination and the endotoxin detoxification chiefly realized by the activity of the mob ... | 1977 | 324185 |
| [enterotoxigenic e. coli]. | | 1977 | 324192 |
| a serologic response in human infection with enterobacteriaceae. | sera from patients infected with escherichia coli, proteus, klebsiella, and serratia were studied for precipitins to ultrasonic extracts of these organisms in gel-diffusion plates. sera from 66 per cent of these patients contained precipitins when initially tested. twenty-four per cent of sera tested in the first week after onset of infection contained precipitins, but this rose to 78 per cent by the third week. cross-reactions of sera with pseudomonas antigens were unusual, but were common with ... | 1977 | 324278 |
| [penicillin amidase from e. coli. a comparative study of the stability of penicillin amidase immobilized by various means]. | the properties of immobilized penicillinamidases prepared by different methods were studied. immobilization of penicillinamidase was achieved by using the covalend binding ion exchange sorption, incorporation into gel and other procedures. the effect of the carrier type, purification level of the native enzyme and other factors on stability of the immobilized preparations was studied. in 4 cases significant stabilization of the enzyme in the immobilized state was observed, while in 3 cases desta ... | 1977 | 324383 |
| plasmid-mediated chloramphenicol resistance in haemophilus influenzae. | a clinical isolate of haemophilus influenzae hc234 was found to be resistant to chloramphenicol and tetracycline. it was shown that both resistance markers are tranferable as one unit to other haemophilus influenzae strains and also to escherichia coli. data are presented which indicate that conjugation is the most likely mechanism of resistance transfer. hc234 was shown to carry a single plasmid species with a molecular weight of 38 x 10(6). | 1977 | 324388 |
| resistance plasmid transfer by serratia marcescens in urine. | resistance plasmids were transferred in urine from a multi-drug-resistant serratia marcescens to escherichia coli. transfer of resistance to kanamycin, tetracycline, chloramphenicol, streptomycin, ampicillin, and carbenicillin occurred readily after 4 h of incubation at room temperature (25 degrees c). the urinary catheter collection bag is postulated as a potential site for extraintestinal resistance plasmid transfer in the enterobacteriaceae, especially for pathogens such as serratia, which do ... | 1977 | 324391 |
| comparison of the actions of 5-fluorouracil and ftorafur in escherichia coli. | the actions of 5-fluorouracil (fu) and ftorafur (ncs 148958) were compared in escherichia coli b3 to determine if ftorafur can act in ways other than through the production of fu. very high concentrations of ftorafur relative to fu were necessary to achieve a comparable inhibition of cell growth. inhibition by both agents could be reversed by uracil. an fu-resistant strain and an ftorafur-resistant strain were isolated and found to be cross-resistant to ftorafur and fu, respectively. | 1977 | 324392 |
| mobilization of morganocin 174 plasmid and kinetics of morganocin production in proteus and escherichia coli hosts. | morganocin 174 is coded by a plasmid, mor174. the plasmid is not self-transmissible but may be mobilized by resistance factor r772. morganocin synthesis in all proteus and providencia strains carrying mor174 was characterized by a longer lag period after induction and higher titers than in escherichia coli b(mor174). the low titers obtained in e. coli b(mor174) are due to a heatstable inhibitor produced by this strain. synthesis of morganocin is not constitutive and may be induced by ultraviolet ... | 1977 | 324393 |
| characterization of an r-plasmid associated with ampicillin resistance in shigella dysenteriae type 1 isolated from epidemics. | ampicillin-resistant strains of shigella dysenteriae type 1 isolated in epidemics in mexico, central america, and bangla desh were examined for the presence of plasmid deoxyribonucleic acid (dna) by gel electrophoresis. all strains contained a heterogeneous population of plasmids. transfer experiments to escherichia coli k-12 indicated that the ampicillin resistance determinant (ap(r)) was located on a 5.5-megadalton (mdal) plasmid identical in all shiga strains examined, as judged by dna hybrid ... | 1977 | 324394 |
| action of the n-trifluoroacetyl analogue of d-chloramphenicol. | the n-trifluoroacetyl analogue of chloramphenicol was found to inhibit the growth of escherichia coli less than chloramphenicol, rather than more as previously reported by others. it also inhibits protein synthesis by e. coli and rat liver mitochondria less. | 1977 | 324395 |
| growth inhibition of escherichia coli w by d-norvalyl-d-alanine: an analogue of d-alanine in position 4 of the peptide subunit of peptidoglycan. | position 4 analogues of d-alanine in the peptide subunit of uridine 5'-diphosphate-n-acetylmuramyl-ala(1)-dglu(2)- lys(3)-dala(4)-dala(5) have a significant inhibitory effect on penicillin-sensitive peptidoglycan synthesis in gaffkya homari (c. v. carpenter, s. goyer, and f. c. neuhaus, 1976). the specificity profile of this in vitro system has been used as a basis for designing analogues with potential antibacterial activity. to circumvent the specificity determinants exerted by d-alanine:d-ala ... | 1977 | 324397 |
| therapy of antimicrobial-resistant typhoid fever. | antimicrobial-resistant typhoid fever in saigon was studied by examining in vitro antimicrobial susceptibilities of salmonella typhi strains and conducting a randomized clinical trial of ampicillin and trimethoprim-sulfamethoxazole (tmp-smz). isolates of s. typhi were obtained from blood or stool cultures of 90 patients. of 87 isolates tested for antimicrobial susceptibility, 65 (75%) were resistant (r) to chloramphenicol, streptomycin, sulfonamide, and tetracycline, and 22 (25%) were susceptibl ... | 1977 | 324398 |
| cefazaflur, a new parenteral cephalosporin: in vitro studies. | cefazaflur was tested in vitro against 262 strains of bacteria. inhibitory and bactericidal concentrations were determined with two inoculum sizes of bacterial cells in mueller-hinton broth and nutrient broth. agar dilution studies also were performed. when tested in agar, 5.0 mug or less of cefazaflur per ml inhibited almost all strains of staphylococcus aureus, escherichia coli, klebsiella, and proteus mirabilis. the drug was less active against enterobacter and indole-positive proteus, and 7. ... | 1977 | 324399 |
| [interaction of cholera vibrios and escherichiae with the intestinal epithelium (histologic and electron microscopic study)]. | histological and electron-microscopic investigations were carried out of ligated small intestinal loops of 147 rabbits within 24 hours after challenge with cholera vibrios el tor, different enterotoxigenic e. coli, choleragen and e. coli enterotoxins. these ogranisms attached themselves to enterocytes and multiplied on the surface of the unaltered intestinal epithelium. thereafter, a greatly pronounced secretion of enterocytes, rather than inflammation, developed, like after the exposure to ster ... | 1977 | 324443 |
| translation of natural mrna in cell-free systems from a polyamine-requiring mutant of escherichia coli. | | 1977 | 324471 |
| antibody levels to enteric bacteria in juvenile rheumatoid arthritis. | in order to determine the immunologic status and possible susceptibility to bacterial infection in children with juvenile rheumatoid arthritis (jra), titer of hemagglutingating antibodies to e coli 055, e coli 086, common antigen, and shigella polyvalent antigen were measured. immunoglobulin g was the predominant antibody. iga antibodies were found in higher titer in children with jra. no significant differences were found between children with jra do not have any deficit in antibody production ... | 1977 | 324480 |
| urinary ldh isoenzyme 5 excretion in experimental pyelonephritis. | studies to determine the effect of kidney parenchymal infection upon urinary lactic dehydrogenase (uldh) isoenzyme composition were performed in 12 female sprague-dawley rats on day 0 and on days 2, 5, and 10, after experimental inducement of escherichia coli pyelonephritis. an additional group of 12 animals was subjected to similar experimental manipulations and served as sham controls. repeated 12-h urine collections revealed lower urine osmolalities and significantly higher levels of uldh 5 e ... | 1977 | 324511 |
| high-resolution nuclear magnetic resonance determination of transfer rna tertiary base pairs in solution. 2. species containing a large variable loop. | the number of base pairs in the solution structure of several class iii d3vn trna species from e. coli has been determined by analyzing the number of low-field (-15 to -11 ppm) proton resonances in their nuclear magnetic resonance spectra at 360 mhz. contrary to previous reports indicating the absence of tertiary resonances, all the spectra exhibit the expected number of secondary base pair resonances plus approximately ten extra resonances derived from tertiary base pairs in the three-dimension ... | 1977 | 324515 |
| modification-deficient transfer ribonucleic acids from relaxed control escherichia coli: structures of the major undermodified phenylalanine and leucine transfer rnas produced during leucine starvation. | the structures of the major, chromatographically unique phenylalanine and leucine trnas produced during leucine starvation of a relaxed control (rel-) mutant of e. coli have been determined. the results demonstrate that the unique species are modification-deficient forms of the major, normally occurring isoacceptor species. the unique trnaphe differs from the fully modified species at nucleotide positions 16, 37, 39, 47, and 55 from the 5' terminus. the unique species contains uridine (u) in pla ... | 1977 | 324516 |
| conversion of bacteriophage g4 single-stranded viral dna to double-stranded replicative form in dna mutants of escherichia coli. | host functions involved in synthesis of parental replicative form of bacteriophage g4 were investigated using various replication mutants of escheria coli. in dna+ bacteria, conversion of single-stranded viral dna to replicative form dna was insensitive to 200 microng/ml of rifampicin or 25 microng/ml of chloramphenicol. at high temperature, synthesis of parental replicative form was unaffected in mutants thermosensitive for dnaa, dnab, dnac(d), dnae or dnah. in dnag or dnaz mutants, however, pa ... | 1977 | 324521 |
| [catabolyte inhibition of lactate transport in escherichia coli]. | e. coli cells growing on the medium containing glucose and lactate do not utilize lactate. one reason of preferential utilization of glucose is catabolite inhibition of lactate transport. it is necessary for glucose to penetrate into the cell to inhibit lactate transport. besides glucose the inhibition of the lactate transport is also caused by fructose and by non-metabolized analogue of glucose--alpha-methylglucoside. | 1977 | 324525 |
| metabolite levels and activities of some enzymes of carbohydrate metabolism in livers and intestines of conventional and bi-associated (with staphylococcus epidermidis and escherichia coli) mice in the course of trichinella spiralis infection. | | 1977 | 324584 |