| cephalexin: clinical and laboratory evaluation in infants and children. | cephalexin appears to be a highly effective antibiotic. it possesses the qualities of rapid oral absorption, production of high drug levels in the blood and urine, and near absence of side effects. it is effective against infections due to gram-positive cocci infections, with the exception of enterococcus, and for most infections caused by e. coli and klebsiella. it is useful in the treatment of a wide variety of infections in infants and children, and particularly valuable with susceptible infe ... | 1977 | 324691 |
| two new bioassay techniques for nitrofurans: bacteroides fragilis and rec-escherichia coli as indicator strains. | techniques for the microbiological assay of nitrofurans are described. in one the indicator strain is bacteroides fragilis; use of this system enables concentrations of nifuratel and furazolidone of down to 0.7 micrograms/ml to be estimated. the other system uses a recombination-deficient (reca-uvra-) mutant of escherichia coli; with this indicator, concentrations of 0.2 micrograms/ml, or less, of five nitrofurans can be assayed. | 1977 | 324721 |
| evidence for the presence of carbohydrate units in the nitrate reductase a of escherichia coli k12. | | 1977 | 324804 |
| d-galactonate utilisation by enteric bacteria. the catabolic pathway in escherichia coli. | | 1977 | 324806 |
| activation of escherichia coli phosphoenolpyruvate carboxylase by guanosine-5'-diphosphate-3'-diphosphate. | | 1977 | 324807 |
| rna of the small subunit of the escherichia coli ribosome with additional protein binding sites. characterization of the structure by electron microscopy. | | 1977 | 324808 |
| the rna binding properties of "native" protein-protein complexes isolated from the escherichia coli ribosome. | | 1977 | 324809 |
| prediction of secondary structures in proteins from the escherichia coli 30 s ribosomal subunit. | | 1977 | 324810 |
| regulation of newly evolved enzymes. iii evolution of the ebg repressor during selection for enhanced lactase activity. | the evolution of lactose utilization by lacz deletion strains of e. coli occurs via mutations in the ebg genes. we show that one kind of mutation in the regulatory gene ebgr results in a repressor which retains the ability to repress synthesis of ebg enzymes, but which permits 4.5-fold more ebg enzyme synthesis during lactose induction than does the wild-type repressor. a comparison between the growth rate of various ebg+ strains on lactose and the amount of ebg enzyme synthesized by these strai ... | 1977 | 324865 |
| complementation test between alkaline phosphatase regulatory mutations phob and phorc in escherichia coli. | a phorc and a phob mutation belong to the same complementation group suggesting that there is a single positive control gene for alkaline phosphatase synthesis. | 1977 | 324866 |
| inhibition of ribonucleases by ribonucleotides and transition state analogs in cell-free extracts from ehrlich ascites tumor cells. | we investigated the ribonucleolytic breakdown of poly(u), poly(a), rna trascribed from calf thymus dna with e. coli rna polymerase, ribosomal rna, trna and mengovirus rna by an enzyme fraction obrained from a postribosomal supernatant of ehrlich ascites tumor cells. the single-stranded homopolyribonucleotides are preferentially degraded by the enzyme fraction with the production of ribonucleoside 5'-monophosphates. the rnase activity is completely dependent on the presence of mg2+ ions and is hi ... | 1977 | 324884 |
| the primary structure of protein l6 from the aminoacyl-trna binding site of the escherichia coli ribosome. | | 1977 | 324885 |
| intestinal immune response to e. coli antigens in the germ-free chicken. | the secretory intestinal immune response to live and heat-inactivated e. coli 02 has been studied in young germ-free chicks. a response to live organisms was evident from an infiltration of the intestinal mucosa with iga and igm immunoglobulin-producing cells (ipc). antibody associated with both immunoglobulin classes which was specific for e. coli 02 was demonstrated in saline extracts of contents from the small intestine. repeated oral immunization with heat-killed e. coli 02 failed to stimula ... | 1977 | 324901 |
| intestinal stimulation of the serum antibody response against escherichia coli o83 antigen in healthy adults. | ingestion of e. coli o83 bacteria preceded by intake of 2 g of nahco3 resulted in the bacteria appearing as a transient strain in the stool in 6 out of 11 healthy adult individuals. no rise in serum, urine or parotid fluid antibody levels against the crude o antigen from e. coli o83 bacteria could be detected using the enzyme-linked immunosorbent assay (elisa) or the indirect haemagglutination (iha) technique. in contrast, a serum antibody response was registered in four individuals with the amm ... | 1977 | 324921 |
| [formation of covalent linkages between the nucleic acid and protein constituents of e. coli mre 600 ribosomes during gamma irradiation]. | gamma-irrdiation of e. coli mre 600 ribosomes in aqueous suspensions leads to covalent linkages between the rna and some ribosomal proteins. the presence of oxygen during the irradiation strongly inhibits this phenomenon. it appears clearly that only a few proteins are able to participate in these cross-linking reactions, which occur simultaneously in the two sub-units. the radiochemical yield was determined at several concentrations and was relatively low. | 1977 | 324935 |
| dnab gene product-independence of dna polymerase iii-directed repair synthesis in escherichia coli k-12. | | 1977 | 324938 |
| in vitro susceptibility of cephalothin-resistant enterobacteriaceae to cefoxitin and bl-s786. | the in vitro antibacterial activity of two agents relatively resistant to beta-lactamases, bl-s786 and cefoxitin, was tested against 123 recent different clinical isolates of cephalothin-resistant enterobacteriaceae. bl-s786 showed considerable activity against escherichia coli and lesser activity against klebsiella pneumoniae with, respectively, 68% and 41% inhibited at 32 microng/ml. cefoxitin showed more activity in vitro against e. coli, k. pneumoniae, serratia marcescens and providencia stu ... | 1977 | 324961 |
| regulation of amino acid transport in escherichia coli by transcription termination factor rho. | amino acid transport rates and amino acid binding proteins were examined in a strain containing the rho-120 mutation (formerly sua), which has been shown to lower the rho-dependent, ribonucleic acid-activated adenosine triphosphatase activity to 9% of the rho activity in the isogenic wild-type strain. tryptophan and proline transport, which occur by membrane-bound systems, were not altered. on the other hand, arginine, histidine, leucine, isoleucine, and valine transport were variably increased ... | 1977 | 324970 |
| menaquinone biosynthesis: mutants of escherichia coli k-12 requiring 2-succinylbenzoate. | two independent mutants of escherichia coli k-12, selected for their inability to grow anaerobically with fumarate as the terminal electron acceptor, were shown to be deficient in menaquinone biosynthesis. in both cases, exogenously supplied 2-succinylbenzoate promoted normal anaerobic growth on a lactate plus fumarate medium. anaerobic growth of the mutants on glucose minimal medium was impaired but could be restored to normal by adding either uracil or 2-succinylbenzoate. the addition of 2-suc ... | 1977 | 324971 |
| partial purification of glycerophosphate acyltransferase from escherichia coli. | glycerophosphate acyltransferase, a membrane-bound enzyme catalyzing the initial step of phospholipid biosynthesis in escherichia coli, has been extracted with triton x-100, a nonionic detergent, and purified 20- to 40-fold. this preparation is free from lysophosphatidate acyltransferase. glycerophosphate acyltransferase is inactive in detergent extracts, but can be reconstituted by the addition of phospholipid. under such conditions, the enzyme is associated with phospholipid. the sole product ... | 1977 | 324973 |
| chloramphenicol-induced changes in the synthesis of ribosomal, transfer, and messenger ribonucleic acids in escherichia coli b/r. | the synthesis of ribosomal ribonucleic acid (rrna), transfer rna (trna) and messenger rna (mrna) was measured in escherichia coli b/r after the addition of 100 mug of chloramphenicol (cam) per ml to cultures growing either in one of three minimal media (succinate, glycerol, or glucose) or in one of the same three media supplemented with 20 amino acids. (i) during cam treatment, rrna and trna were synthesized in the same relative proportions (85:15) as during exponential growth. the faster accumu ... | 1977 | 324974 |
| rate of ribosomal ribonucleic acid chain elongation in escherichia coli b/r during chloramphenicol treatment. | in escherichia coli b/r growing in glucose-amino acids medium, the radioactive labeling of 5s ribosomal ribonucleic acid (rrna) and transfer rna (trna) was measured after the simultaneous addition to the bacteria of chloramphenicol (cam) (100 mug/ml), rifampin (200 mug/ml), and radioactive uracil. accumulation of 5s rrna ceased 85 s after the addition of rifampin, independent of the presence or absence of cam; this indicates that cam did not affect the rrna chain growth rate. together with previ ... | 1977 | 324975 |
| energy requirements for the transport of methylthio-beta-d-galactoside by escherichia coli: measurement by microcalorimetry and by rates of oxygen consumption and carbon dioxide production. | the energy cost for maintenance of gradients of methylthio-beta-d-galactoside in escherichia coli was evaluated. information was also obtained concerning the energy flow associated with gradient establishment under some circumstances. energy flow was evaluated from transport-induced changes in the rate of heat evolution, oxygen consumption, and carbon dioxide production in metabolically active cells. heats were measured with an isothermal calorimeter. energy expenditure behavior was characterize ... | 1977 | 324976 |
| determination of deoxyribonucleic acid replication time in exponentially growing escherichia coli b/r. | the time necessary to replicate the chromosome (c period) was measured in escherichia coli b/r (atcc 12407) and a low-thymine-requiring derivative of that strain. in the thy- strain, c was measured as a function of growth rate and exogenous thymine concentration either from step-up or chloramphenicol experiments. in the thy+ parental strain, c was measured only as a function of the growth rate and only by the chloramphenicol method. the c period was found to decrease with growth rate and, in the ... | 1977 | 324977 |
| genetics of sensitivity of salmonella species to colicin m and bacteriophages t5, t1, and es18. | nearly all of 62 strains of salmonella paratyphi b were sensitive to colicin m and phage t5 but resistant to phages t1 and es18 and to colicin b. all tested s. typhimurium strains were resistant to colicin m and phage t5, and many were sensitive to phage es18. a rough s. typhimurium lt2 strain given the tona region of escherichia coli or s. paratyphi b became sensitive to colicin m and phage t5. we infer that the tona allele of s. paratyphi b, like that of e. coli, determines an outer membrane p ... | 1977 | 324978 |
| independent regulation of transport and biosynthesis of arginine in escherichia coli k-12. | from an arginine auxotrophic strain, a mutant was isolated which is able to utilize d-arginine as a source of l-arginine and shows a high sensitivity to inhibition of growth by canavanine. transport studies revealed a four- to five-fold increased uptake of arginine and ornithine in cells from the mutant strain. the kinetics of entry of arginine and ornithine evidenced elevated maximal influx values for the arginine- and ornithine-specific transport systems. a close parallel between arginine tran ... | 1977 | 324979 |
| identification of polypeptides necessary for chemotaxis in escherichia coli. | molecular cloning techniques were used to construct escherichia coli-lambda hybrids that contained many of the genes necessary for flagellar rotation and chemotaxis. the properties of specific hybrids that carried the classical "chea" and "cheb" loci were examined by genetic complementation and by measuring the capacity of the hybrids to direct the synthesis of specific polypeptides. the results of these tests with lambda hybrids and with a series of deletion mutations derived from the hybrids r ... | 1977 | 324984 |
| inhibition of histoplasma capsulatum ribonucleic acid polymerases by homologous and heterologous ribonucleic acid. | the ribonucleic acid (rna) polymerases from the yeast phase of histoplasma capsulatum are differentially sensitive to rna isolated from the yeast and mycelial phases of this fungus and from escherichia coli. low-molecular-weight rna from h. capsulatum was the most effective inhibitor. | 1977 | 324986 |
| deoxyribonucleic acid strand breaks during freeze-drying and their repair in escherichia coli. | freeze-drying of escherichia coli cells caused strand breaks of deoxyribonucleic acid (dna) in both radiation-sensitive and -resistant strains. however, in the radiation-resistant strain e. coli b/r the damaged dna was repaired after rehydration, whereas in the radiation-sensitive strain e. coli bs-1 the damaged dna was not repaired and the dna was degraded. repeated freeze-drying did not break the damaged dna into smaller pieces. | 1977 | 324987 |
| characterization of plasmids in a sucrose-fermenting strain of escherichia coli. | a multiply drug-resistant strain of escherichia coli isolated from a patient in bangladesh was shown to carry four types of plasmids based on size differences. one type carries a gene or genes for sucrose fermentation. | 1977 | 324988 |
| structural specificity of the allosteric inhibitor of phosphoenolpyruvate carboxylase of escherichia coli. | the structural specificity of the allosteric inhibitor of phosphoenolpyruvate carboxylas [ec 4.1.1.31] of escherichia coli w was investigated using native enzyme and photooxidized enzyme which was desensitized to l-aspartate. inhibitory activity was expressed in terms of the concentration of the compound required for 50% inhibition (i0.5). for the native enzyme, l-aspartate and l-malate were the strongest inhibitors with i0.5 values of about 0.10-0.15 mm among about 20 componds tested. for the p ... | 1977 | 324991 |
| lipid-protein interactions in membranes: interaction of phospholipids with respiratory enzymes of escherichia coli membrane. | | 1977 | 324993 |
| dna n-glycosidases: properties of uracil-dna glycosidase from escherichia coli. | | 1977 | 324994 |
| use of 3h and 14c double-labeled glucose to assess in vivo pathways of amino acid biosynthesis in escherichia coli. | 3h and 14c tracing data concerning amino acid biosynthetic pathways in escherichia coli k12 are presented. thirteen acidic and neutral amino acids were isolated from protein hydrolysates of wild type e. coli k12 grown aerobically or anaerobically in the presence of [u-14c]glucose together with [1-3h]glucose, [3-3h]glucose, [4-3h]glucose, or [6-3h]glucose. the observed 3h/14c counts of the amino acids were compared with the ratios expected on the basis of the input substrate specific activities a ... | 1977 | 324995 |
| amino acid sequence of escherichia coli biotin carboxyl carrier protein (9100). | the amino acid sequence of a proteolytic fragment of escherichia coli biotin carboxyl carrier protein was determined from the structures of overlapping tryptic, thermolytic, and staphylococcal protease peptides together with automated sequenator analyses on the intact protein. the fragment, 82 residues in length, contains the single residue of biocytin of the protein. the relationship of the mr = 9100 fragment to the native mr = 22,500 subunit is discussed. | 1977 | 324999 |
| structural requirements of escherichia coli formylmethionyl transfer ribonucleic acid for ribosome binding and initiation of protein synthesis. | | 1977 | 325000 |
| relation of turnover of membrane phospholipids to synthesis of membrane-derived oligosaccharides of escherichia coli. | | 1977 | 325003 |
| 19f nuclear magnetic resonance of 5-fluorouridine-substituted trna1val from escherichia coli. | the 19f nmr spectrum of escherichia coli trna1val in which [5-19f]uridine replaces 93% of all uridine and uridine-derived residues has been examined at 93.6 and 235 mhz. the resolution of 11 peaks and visibility of two additional shoulders at either frequency for the 14 fura residues in the molecule attests to the excellence of 19f as a probe for the structure of trna1val in solution. no significant gain in resolution was attained at the higher frequency. a comparison of the relative areas in th ... | 1977 | 325008 |
| a microbiological investigation of acute summer gastroenteritis in black south african infants. | a microbiological investigation of black infants suffering from severe acute summer gastroenteritis revealed enteropathogenic agents in 30 out of 37 patients (81%). enterotoxigenic bacteria were isolated from 15 patients (41%). a total of 16 enterotoxigenic strains were isolated, comprising 9 enterotoxigenic escherichia coli strains secreting labile and stable toxin on their own and in combination, and labile-toxin secreting strains of klebsiella pneumoniae (4), enterobacter cloacae (2) and prot ... | 1977 | 325127 |
| role of ionic strength in colicin k adsorption. | the rate of colicin k adsorption to escherichia coli, and consequent death of the bacteria, is progressively inhibited with increasing ionic strength of the medium. comparison of the kinetics of colicin adsorption with the kinetics of colicin killing suggests that the lethal event provoked by colicin occurs soon after irreversible colicin adsorption. factors, such as salts, which protect bacteria against the lethal action of colicin act by preventing colicin adsorption. | 1977 | 325176 |
| location of the gene specifying hexose phosphate transport (uhp) on the chromosome of escherichia coli. | the uhp gene, which specifies the uptake of hexose phosphates, and several other genes in the vicinity of minute 81 on the e. coli linkage map have been located by phage-mediated transductions. the order found is mtl-gpsa-pyre-gltc-uhp-tna-dnaa. alleles specifying the uhp- and uhp+ characters were separated from that specifying constitutivity of hexose phosphate uptake (uhpc). although cotransduction frequencies between gltc and uhp as high as 90%, and between uhp and tna as high as 80%, were ob ... | 1977 | 325177 |
| timing of cold-sensitive stages in the cell division cycle of escherichia coli k12. | synchornous cultures obtained by selection at division were used to investigate the occurrence of cold-sensitive stages during the division cycle of escherichia coli (lambdaind--). there are two such stages within the 50 min cycle: one (early) at 10 to 20 min and the other (late) at 40 to 45 min. similar results were obtained from calculations based both on the age frequency distribution of cells in exponential growth and on the size of the populations which accumulate as a result of a single ch ... | 1977 | 325179 |
| immune function in ankylosing spondylitis: apparent relationship between streptococcal responses and hla b27. | immune function has been evaluated in 54 patients with ankylosing spondylitis (as) and 26 controls. cell-mediated immunity was assessed by skin testing with ubiquitous antigens, and humoral immunity by antibody responses to tetanus toxoid and salmonella typhi vaccinations, and resting titres of anti-streptolysin o, anti-e coli, and isohemagglutinins. the as patients had reduced delayed hypersensitivity responses to candida, augmented responses to streptococcal antigen and relatively low aso titr ... | 1977 | 325206 |
| studies on the primary structure of escherichia coli 23 srna. nucleotide sequence of the ribonuclease t1 digestion products containing more than one uridine residue. | | 1977 | 325211 |
| state of the dna replication fork during thymine deprivation of escherichia coli, as observed by pulse-labelling with [3h]thymidine. | | 1977 | 325216 |
| effects of temperature and host cell genetic characteristics on the replication of the lipid-containing bacteriophage pr4 in escherichia coli. | the lipid-containing bacteriophage pr4 is of special intest because it can replicate in various gram-negative bacteria, including escherichia coli, that carry one of a group of drug resistance plasmids. pr4 grown in e. coli strain ps2r contains about 10% lipid by weight, with the negatively charged phospholipid phosphatidylglycerol being the most abundant lipid in the virion. we now report the following. (i) pr4 attaches to e. coli with an attachment rate constant of ka approximately 6.2 x 10(-1 ... | 1977 | 325229 |
| intracellular organization of bacteriophage t7 dna: analysis of parenteral bacteriophage t7 dna-membrane and dna-protein complexes. | after infection of escherichia coli with bacteriophage t7, the parenteral dna forms a stable association with host cell membranes. the dna-membrane complex isolated in cesium chloride gradients is free of host dna and the bulk of t7 rna. the complex purified through two cesium chloride gradients contains a reproducible set of proteins which are enriched in polypeptides having molecular weights of 54,000, 34,000, and 32,000. all proteins present in the complex are derived from host membranes. tre ... | 1977 | 325231 |
| alteration of the escherichia coli membrane by addition of bacteriophage t4 protein synthesized after infection. | many t4-induced proteins were found associated with the escherichia coli membrane during infection. some of these were apparently ionically bound, but many could be identified as integral parts of the inner and outer bacterial membranes by their selective solubilities in guanidine or sarkosyl. the synthesis and insertion of these proteins into the bacterial membrane were temporally controlled and, once in the membrane, these proteins were stably integrated. host membrane protein synthesis contin ... | 1977 | 325233 |
| bacteriophage proteins associated with the bacterial membrane after bacteriophage t7 infection. | the majority of the phage-induced proteins made after t7 infection of escherichia coli are tightly associated with the bacterial membrane. many of these have been identified. selective extraction of proteins from these membranes by the detergent sarkosyl or the chaotropic agent guanidine-hydrochloride indicated that most of these proteins are an integral part of the cytoplasmic membrane and the cell wall. no major changes in the distribution of bacterial proteins in the membrane were observed as ... | 1977 | 325234 |
| [supersynthesis of beta-galactosidase in escherichia coli cells]. | | 1977 | 325328 |
| dna synthesis in an escherichia coli dna b dnac mutant. | an escherichia coli k12 dnab dnac mutant was constructed by p1 transduction of the dnac allele into a dnab recipient stain. dnab dnac transductant were discriminated from dnab mutants by their inability to grow at 40 degree c after lysogenization with phage p1bac. the dnab dnac mutant character was verified by 1. p1 transduction, and 2. by in vitro complementation with dnab and dnac wild type protein fractions. dna synthesis was studied in strains containing dnab, dnab dnac alleles in an otherwi ... | 1977 | 325362 |
| characterization of an e. coli mutant with a thermolabile initiation factor if3 activity. | a thermosensitive e. coli mutant is described which has at least two defects in vitro: a thermolabile initiation factor if3 activity and a modified l-phenylalanine: trnaphe ligase (ec 6.1.1.20) activity. these two defects cotransduce and are located near 38 min on the new e. coli map. thermoresistant revertants showing in vitro reversion for one defect also revert in vitro for the other defect. the thermosensitive mutation is recessive to its wild type allele, and in vitro analysis of wild type/ ... | 1977 | 325363 |
| a new host gene (gropc) necessary for lambda dna replication. | the isolation of a bacterial mutation in a gene, designated gropc, which affects the growth of phages lambda and p2 is described. lambda replication is severely limited in the strain, and some lambda pi mutations, which map in (or near) the p gene, allow growth. the gro mutation, gropc259, is recessive to wild type and maps between threonine (thr) and diaminopimelate (dapb) on the e. coli chromosome. the possibility that the gropc gene is concerned with host dna replication is discussed. | 1977 | 325364 |
| expression and stability of escherichia coli f-prime factors in proteus mirabilis. | the expression and stability of escherichia coli f-primes in proteus mirabilis is examined. it is possible to consecutively introduce, and stably maintain, the dna of several e. coli f-primes in p. mirabilis in the absence of selective pressure for all or some of the plasmids. additionally, we can recover more than one f-prime from certain p. mirabilis recipient strains which carry dna derived from several independent matings with e. coli f-prime donors. | 1977 | 325366 |
| induction of protein synthesis in escherichia coli following uv- or gamma-irradiation, mitomycin c treatment or tif expression. | the rate of synthesis of total cellular proteins has been studied by pulse labelling cells at various periods after irradiation with uv or gamma-rays, after treatment with mitomycin c (mmc) or after expression of the temperature sensitive mutation tif. subsequent gel electrophoresis and autoradiography reveals changes in the rate of synthesis of several proteins. the most striking change is in a protein of molecular weight 40,000, protein x, which has been previously most extensively studied in ... | 1977 | 325368 |
| identification of an amber fragment of the beta subunit of escherichia coli rna polymerase: a yardstick for measuring controls on rna polymerase subunit synthesis. | an amber fragment of the beta subunit of escherichia coli rna polymerase has been recovered from strains carrying the rpob12 amber mutation, indicating that the b12 mutation resides in the structural gene for the beta subunit. the fragment is readily assayed and can be used to determine the degree of expression of a single rpob cistron in strains haploid or diploid for this region. these studies confirm that the bacterial mechanism, which can compensate for reduced translation of the beta mess ... | 1977 | 325370 |
| translational fidelity in escherichia coli: contrasting role of neaa and rama gene products in the ribosome functioning. | strains carrying both the rama1 and the neaa301 mutations do not exhibit the restriction of informational suppressors normally associated with resistance to neamine. furthermore, ribosomes from such strains exhibit increased misreading in vitro with respect to particles from the neaa strain. these properties suggest that translational fidelity may be cooperatively controlled by ribosomal proteins s4 and s17, coded by rama (rpsd) and neaa (rpsq) genes respectively. | 1977 | 325371 |
| construction and restriction endonuclease mapping of hybrid plasmids containing saccharomyces cerevisiae ribosomal dna. | fragments produced by partial digestion of saccharomyces cerevisiae ribosomal dna (rdna) with the restriction endonuclease ecori were ligated in vitro to the bacterial plasmid rsf2124. the resulting hybrid plasmids were cloned in escherichia coli. three hybrid plasmids which contain at least one intact repetitive unit of the multiple, tandem sequences of the yeast rdna genes have been further characterized. these plasmids have been used to construct a map of the ecori, smai, hindii and hindiii r ... | 1977 | 325373 |
| suppression of polarity of insertion mutations within the gal operon of e. coli. | phenotypic revertants of galop::is1 and galop::is2 mutations have been isolated after mutagenesis with nitrosoguanidine, they are probably caused by mutations in gene sua. the polarity suppressor mutations described in this study and a known mutation in gene sua isolated by d. morse (morse and guertin, 1972) suppress polarity caused by is1 more effectively than that caused by is2 or is4. furthermore, suppressibility is influenced by the site and orientation of is integration. the synthesis of th ... | 1977 | 325374 |
| in vitro transcription of the ribosomal rna genes of e. coli dna. | bacterial ribosomal rna synthesis was studied in an in vitro system in which the presence of heparin prevented reinitiation of transcription. the number of heparin-resistant binary complexes of rna-polymerase and e. coli dna depended strongly on the quality of the template. high-molecular weight dna was a much superior template than dna prepared by conventional techniques. using this high-molecular weight dna as template the amount of ribosomal rna synthetized in one round of transcription was f ... | 1977 | 325375 |
| growth and reactivation of single stranded dna phage phix174 in e. coli undergoing "thymineless death". | the thymine requirement of the e. coli strain hf 4704 (uvr a-, rec a+) is thermosensitive i.e. these cells require for their growth 2 microng thymine per ml at 37 degrees c but not at 30 degrees c. such cells when starved for thymine for 3 h at 37 degrees c are capable of sustaining growth of single stranded dna phage phix174 without any diminution of burst size under nonpermissive conditions. thymine starved hf 4704 cells also reactivate uv-irradiated phix174 by about 3fold. to test if the thym ... | 1977 | 325376 |
| mechanism of conjugation and recombination in bacteria xvi: single-stranded regions in recipient deoxyribonucleic acid during conjugation in escherichia coli k-12. | the formation of mating pairs between f- and hfr cells resulted in increased sensitivity of recipient deoxyribonucleic acid (dna) to single-strand-specific s1 nuclease, from 3.6% to 23.5% after 30 min conjugation. a comparable amount of single strand regions in the dna of mated wild type and reca mutant cells was detected. 10 min of conjugation resulted in almost the same amount of single-strand recipient dna as 30 min of continuous transfer of donor dna. also the transfer of plasmid dna from f+ ... | 1977 | 325377 |
| in vitro transcription of three different ribosomal rna cistrons of e. coli; heterogeneity of control regions. | ribosomal rna synthesis from three different rrna cistrons of e. coli, located on different phage dnas was compared and found to have the same characteristics as regards chain length, salt and temperature dependence and the effect of ppgpp. however, some clear and reproducible quantitative differences between rrna synthesis from the different templates both in presence and absence of ppggpp were found. rifampicin and heparin experiments showed that these differences were located at the initiatio ... | 1977 | 325380 |
| chromosomal location of gene governing the trehalose utilization in escherichia coli k12. | several mutants unable to utilize trehalose were isolated from escherichia coli, their genetic analysis led to determine the following gene order on the chromosomal map: pur b-dad r-tre-hem a-trp. furthermore, the tre gene belongs to the inversion of the trp chromosomal region between e. coli and s. typhimurium. | 1977 | 325381 |
| antimutagenic effects of spermine and guanosine in continuous cultures of escherichia coli mutator strain muth. | in e. coli strain rh531 containing mutator gene muth-, whose mechanism of enhanced mutability depends upon dna replication, spermine and guanosine reduce the rates of mutation to t5r and to increased fitness. | 1977 | 325382 |
| bromouracil mutagenesis in escherichia coli evidence for involvement of mismatch repair. | | 1977 | 325383 |
| mutagenesis of lambda phage: 5-bromouracil and hydroxylamine. | mutagenesis by 5-bromouracil of lambda phage to clear plaque formers does not depend on the reca function of the host e. coli cell or on the red function of the phage. pretreatment of the host cells with ultraviolet light does not affect bromouracil mutagenesis of the adsorbed phage. mutagenesis by hydroxlamine to clear plaque formers takes place at a high level in reca- host cells, and is not changed by preirradiation of of rec+ (wild type) hosts with ultraviolet light. thus, bromouracil and hy ... | 1977 | 325384 |
| the involvement of polynucleotide ligase in the repair of uv-induced dna damage in escherichia coli k-12 cells. | the effect of the ligts-7 mutation on cell survival and the extent of dna repair after uv (254 nm) irradiation was determined for wild-type and uvrb5 cells of e. coli k-12 at 30 degrees and 42 degrees c. at the restrictive temperature (42 degrees c) the ligts-7 mutation resulted in (i) a decrease in the extent of repair of dna incision breaks arising during the excision repair process, and (ii) a decrease in the extent of post-replicational repair of gaps in newly-synthesized dna. these deficien ... | 1977 | 325385 |
| specialized transduction of the biotin region of escherichia coli by phage t1. | | 1977 | 325388 |
| replication of prophage p1 during the cell cycle of escherichia coli. | we have followed, by dna-dna hybridization, the variation in the number of copies of prophage p1 relative to two chromosomal markers when the doubling time of the host cells is modified by a change in carbon source. the ratio of p1/chromosome terminus undergoes a twofold decrease when the cell doubling time increases from 24 to 215 min, whereas the ratio of p1/chromosome origin increases 1.4 fold; both ratios tend towards unity at slow growth rates. this suggests that the replication of prophage ... | 1977 | 325389 |
| analysis of mutations affecting the dissmilation of galactitol (dulcitol) in escherichia coli k 12. | | 1977 | 325390 |
| plasmid (pkm101)-mediated enhancement of repair and mutagenesis: dependence on chromosomal genes in escherichia coli k-12. | the drug resistance plasmid pkm101 plays a mojor role in the ames salmonella/microsome carcinogen detecting system by enhancing chemical mutagenesis. it is shown that in escherichia coli k-12 the plasmid pkm101 enhances both spontaneous and methyl methanesulfonate-caused reversion of an ochre mutation, bacterial survival after ultraviolet irradiation, and reactivation of ultraviolet-irradiated lambda in unirradiated cells. all these effects are shown to be dependent on the reca+ lexa+ genotype b ... | 1977 | 325391 |
| physiological modification of alkylating agent induced mutagenesis. ii. influence of the numbers of chromosome replicating forks and gene copies on the frequency of mutations induced in escherichia coli. | the frequency of reversions induced in escherichia coli k-12 trpa58 by any of five different monofunctional alkylating agents increased as the growth rate of the organism was raised prior to mutagen treatment. the increase in mutation frequency did not correlate with growth rate-dependent changes in cell area or total cellular protein and dna. after treatment of cells with n-methyl-n-nitrosourea (mnua), no growth rate-dependent change was observed in the total dna alkylation or percentage of o6- ... | 1977 | 325398 |
| a new pathway for dna repair in escherichia coli. | | 1977 | 325420 |
| [preliminary observations on the possible use of platelets as a cellular system in order to check the enteropathogenic activity of escherichia coli and other enterobacteria (author's transl]. | | 1977 | 325483 |
| studies of the pathogenesis of enteric e. coli infections in weaned pigs: bacteriological and immunofluorescent studies. | qualitative and quantitative, bacteriological studies were performed on spontaneous cases of post weaning e. coli diarrhoea (pwd). the pigs derived from a herd, d, in which the disease had persisted for a period of almost 2 years. orally vaccinated healthy pigs from herd d and from herds a and m without the disease were also examined. the results showed that haemolytic e. coli were frequently isolated from faecal samples which had been collected 5--7 days after weaning but seldom from samples fr ... | 1977 | 325502 |
| differential requirements for polypeptide chain initiation complex formation at the three bacteriophage r17 initiator regions. | the initiation specificity of washed e. coli ribosomes in the presence and absence of purified initiation factors and/or s1 protein has been examined in protection experiments using 32p-labelled r17 rna. we find that the three bacteriophage initiator regions do not exhibit equal requirements for either of these components during initiation complex formation. specifically, both factors and s1 stimulate ribosome binding to the beginnings of the coat and replicase cistrons to a greater extent than ... | 1977 | 325516 |
| proton magnetic resonance spectra of trna-met-f from thermus thermophilus. | 220 mhz proton magnetic resonance spectra of trnas in bulk and trna-met-f from thermus thermophilus have been measured and compared with those of trnas from e. coli. temperature dependences and chemical shift positions of the bulk trnas are well explained by the difference in their gc contents. it is known that the base sequence of the double helical regions in the cloverleaf structure of t. thermophilus trna-met-f is different from that of e. coli trna-met-f only at two positions in tpsicarm; o ... | 1977 | 325519 |
| on the binding of aminoalkyl adenylates to isoleucyl-trna synthetase from escherichia coli mre 600. | the binding of nine aminoalkyl adenylates to isoleucyl-trna synthetase from escherichia coli mre 600 was measured and compared with the binding of the cognate amino acids. it was found that they bind rather tightly to the enzyme, the kd's ranging from 3.1.10(-4) m with glycinol-amp ester to 3.7.10(-9) m with l-isoleucinol-amp ester. the binding is not affected by magnesium. it is shown that the free energies of binding of the esters can be calculated adding a constant contribution of the amp-moi ... | 1977 | 325520 |
| synthesis of oligonucleotides with sequences identical with or analogous to the 3'-end of 16s ribosomal rna of escherichia coli: preparation of m-6-2-a-c-c-u-c-c and a-c-c-u-c-m-4-2c via phosphotriester intermediates. | the synthesis of two fully-protected hexanucleotides (11a and 11b) via a phosphotriester approach, which is based on the use of two types of protecting groups for the internucleotide linkages, i.e. one 2,2,2-tribromo-ethyl at the 5'-terminus and four 2-chlorophenyl groups for the remaining linkages, is reported. the hexanucleotides 11a and 11b, assembled via a block-wise two-step phosphotriester method, can be deblocked conveniently to give the two hexamers 12a and 12b containing only 3'leads to ... | 1977 | 325521 |
| synthesis of oligonucleotides with sequences identical with or analogous to the 3'-end of 16s ribosomal rna of escherichia coli: preparation of a-c-c-u-c-c via the modified phosphotriester method. | a combination of two different methods for the synthesis of oligoribonucleotides, i.e. the two-step phosphotriester method with 2-chlorophenyl phosphate as bifunctional phosphate source and the modified triester method with 2,2,2-trichloroethyl 2-chlorophenyl phosphorochloridate as monofunctional phosphate source, is applied for the synthesis of the fully-protected hexaribonucleotide a-c-c-u-c-c. the two-step method is used for the synthesis of the required dinucleotide monophosphates 9, 10 and ... | 1977 | 325524 |
| specific cleavage of ribosomal rna caused by alpha sarcin. | alpha sarcin causes the specific cleavage of rna from 80s ribosomes and 60s subunits of yeast, but not from the 40s subunits to produce a small rna fragment. the fragment was also produced on treatment of the 60s subunits of wheat germ ribosomes. the fragment has a molecular weight of 100,000 and is a cleavage product of the large rna species in the 60s subunits. the fragment is not derived from the 5'end of the yeast 25s rna nor does it bind to 5.8s rna and we propose that the fragment represen ... | 1977 | 325525 |
| transcription in vitro of bacteriophage lambda 4s rna: studies on termination and rho protein. | when bacteriophage lambdapga18 dna is transcribed in a purified in vitro system by e. coli rna polymerase (nucleoside triphosphate: rna nucleotidyl-transferase, ec 2.7.7.6), several major transcripts are synthesized. we have investigated transcriptional termination of one of these transcripts, the 4s, or "oop" rna. analysis by two-dimensional "fingerprinting" of t1 oligonucleotides reveals that transcription of the 4s rna terminates at a specific site on the lambdapga18 dna template, t-l with an ... | 1977 | 325526 |
| the presence of rnase ii in high salt washed e. coli ribosomes: effect on circular dichroism of ribosomal complexes. | traces of the exonuclease rnase ii are retained by e. coli ribosomes purified by conventional high salt washing. the residual activity can give rise to serious artifacts, especially in physical studies. | 1977 | 325527 |
| effect of salt on the transcription of t7 dna by rna polymerase from t4 phage-infected e.coli. | transcription of t7 dna by t4 core enzyme with host sigma is more sensitive to kci than that by host core enzyme with host sigma. when salt is added after initiation of rna chains has occurred, it is not inhibitory. salt affects the binding of t4 enzyme to t7 dna to the same degree as the binding of host enzyme. active preinitiation complex formation is inhibited more by salt with the t4 enzyme and the inhibition is temperature-dependent. | 1977 | 325528 |
| affinity of intact escherichia coli for hydrophobic membrane probes is a function of the physiological state of the cells. | the fluorescence parameters of several common membrane probes in the presence of whole e. coli have been examined. the probes included electrically neutral lipophilic molecules n-phenyl-1-naphthylamine, pyrene, and 1,6-diphenyl-1,3,5-hexatriene as well as the negatively charged molecule 8-anilino-1-naphthalene sulfonate. it is demonstrated in each case that certain fluorescence parameters are a function of the state of energization of the cells. all the probes appear to monitor structural change ... | 1977 | 325554 |
| chromosomal location of a structural gene for the rna polymerase sigma factor in escherichia coli. | a set of f' strains of escherichia coli k-12 partially diploid for various chromosomal segments has been examined for possible gene dosage effects in the synthesis of sigma factor of the dna-dependent rna polymerase (rna nucleotidyltransferase; nucleoside-triphosphate:rna nucleoti-dyltransferase, ec 2.7.7.6). it was found that all f' strains diploid for the dnag region synthesize sigma at rates two to three times higher than other f' or f- strains. moreover, strains of salmonella typhimurium har ... | 1977 | 325555 |
| a gene from escherichia coli affecting the sigma subunit of rna polymerase. | the rna polymerase sigma subunits of escherichia coli k, e. coli c, and salmonella typhimurium can be resolved by electrophoresis. using this technique, we have analyzed salmonella strains carrying f' plasmids from e. coli k in order to map the gene for the sigma factor. partial diploid analyses show the location of the sigma gene at 62-66 min on the e. coli genetic map. this gene is cotransducible with toic and dnag, at 66 min. | 1977 | 325556 |
| microenvironment of the binding site in the lac carrier protein. | studies with a homologous series of (n-dansyl)aminoalkyl-1-thio-beta-d-galactopyranosides containing two to six methylene carbons bridging the galactosyl and dansyl ends of the molecules are described. the compounds were utilized in radioactive and nonradioactive form, and binding of each homologue to membrane vesicles isolated from escherichia coli ml 308-225 was measured directly by flow dialysis in the presence of d-lactate. the results are compared with the d-lactate-induced fluorescence enh ... | 1977 | 325557 |
| dynamic structure of whole cells probed by nuclear overhauser enhanced nitrogen-15 nuclear magnetic resonance spectroscopy. | the proton-decoupled 15n fourier transform nuclear magnetic resonance (nmr) spectra of 15n-enriched escherichia coli, bacillus licheniformis, baker's yeast, and friend leukemic cells were obtained. the 15n nmr spectra of whole cells displayed 15n resonances originating from (i) protein backbones with lysine, arginine, and histidine side chains, (ii) ribonucleic acids, (iii) peptidoglycan, and (iv) phospholipids. several additional amino and amide resonances were observed but not identified. in b ... | 1977 | 325563 |
| associated leukocyte responses in the lethal aspects of e. coli shock. | | 1977 | 325570 |
| effect of quinacrine on survival of ultraviolet-irradiated uvr, rec, lex and pol mutants of escherichia coli k-12. | | 1977 | 325584 |
| endogenous e. coli endophthalmitis. | a case of escherichia coli septicemia with associated metastatic en dophthalmitis and endocarditis is presented. the ocular signs and symptoms were the initial manifestations of sepsis. irreversible damage to the eye occurred in less than 24 hours. the pattern of metastatic bacterial endophthalmitis has changed since the introduction of potent antimicrobial agents, with an increased incidence of gram-negative bacillemia. e. coli endophthalmitis carries a poor prognosis. early diagnosis and syste ... | 1977 | 325673 |
| [successful poteceptil treatment of endocarditis caused by e. coli]. | | 1977 | 325676 |
| [cross-infection during scalding and plucking of broiler chickens (author's transl)]. | in two poultry-processing plants, experiments were carried out to detect cross-infection during scalding and plucking of broiler chickens. these trials showed that cross-infection was only detectable when experimental infection with the indicator micro-organism escherichia coli k12 was applied externally to the broiler chickens. when infection was applied internally, only a small degree of transmission was observed. indicator micro-organisms applied externally to broiler chickens prior to scaldi ... | 1977 | 325684 |
| [study of the antibodies to e. coli in pyelonephritis in children]. | | 1977 | 325900 |
| the effect of stored blood on mesenteric oxygen extraction during exdotoxin shock. | storage of blood in acid-citrate-dextrose (acd) solution gradually depletes red cell 2,3-diphosphoglycerate (dpg) and increases the affinity of hemoglobin for oxygen. we examined the effect of exchange transfusion of dpg-depleted blood on mesenteric blood flow and oxygen consumption in dogs subjected to endotoxin shock. two groups of 6 dogs each were anesthetized and subjected to exchange transfusion with either fresh acd blood or 21-day-old acd blood prior to administration of escherichia coli ... | 1977 | 325917 |
| [transient behavior of the ammonium-limited chemostatic cultures of escherichia coli ml 30]. | in connection with the bistability of pyruvate formation in ammonium limited continuous cultures of e. coli ml 30 (bergter u. roth 1977) the transient behaviour of cell density and pyruvate concentration were studied. immediately after a shift up in the dilution rate from d = 0.15 h-1 to d = 0.6 h-1 the bacteria excreted pyruvate into the medium, followed by a resumption of pyruvate. the specific pyruvate formation rate as well as the specific growth rate reached the new steady state with damped ... | 1977 | 325924 |
| low temperature inhibition on binding, trasport, and incorporation of leucine, arginine, methionine, and histidine in escherichia coli). | a multiple amino acid auxotroph and a wild type of escherichia coli k12 were used to study the effects of near minimum growth temperatures on the binding, transport, and cellular incorporation of selected amino acids. both strains of the bacterium showed the same minimum growth temperature (8 degrees c) when previously grown at 15 degrees c. at 8 degrees c and above, the auxotroph exhibited an overall greater ability to bind and transport amino acids than did the wild type. below the minimum gro ... | 1977 | 325925 |
| induction of lymphocyte proliferation and membrane changes by lipopeptide derivatives of the lipoprotein from the outer membrane of escherichia coli. | lipoprotein from the outer membrane of e. coli, a potent novel mitogen, was digested by pronase treatment resulting in lipopeptide fragments containing 2-5 amino acids bound to diacylglyceryl-n-acylcysteinthioether. the lipopeptides were characterized by amino acid analysis and gas chromatography and were checked for mitogenicity. we found that all lipopeptide fragments were able to stimulate the uptake of 3h-uridine into rna and 3h-thymidine into dna in mouse spleen cells of several strains. th ... | 1977 | 325934 |