| economic impact of rotavirus and other neonatal disease agents of animals. | methods for estimating the economic impact of disease agents were developed and utilized to assess the relative economic importance of rotavirus and other disease agents in calves. based on incidence data from 2 sources, escherichia coli was responsible for the most devastating economic losses (50.9% and 74.6%). coronaviral (17.5% and 29.7% loss) and rotaviral (3.2% and 9.1% loss) infections ranked 2nd and 3rd, respectively. in one study, cryptosporidial infections (6.5% loss) were estimated to ... | 1978 | 212403 |
| pathogenic relationships of rotavirus, escherichia coli, and other agents in mixed infections in calves. | infection with agents interpreted as causing or contributing to diarrhea (rotavirus, coronavirus, enterotoxigenic escherichia coli, and cryptosporidia) were demonstrated in 24 of 32 newborn calves that had naturally occurring diarrheal disease. the calves were from 12 herds in iowa. infections as well as enteric lesions and hypoglobulinemia occurred more frequently among diarrheal calves than among nondiarrheal calves from these same herds. in most calves, infections were mixed; ie, both viruses ... | 1978 | 212404 |
| autophosphorylation of rabbit skeletal muscle cyclic amp-dependent protein kinase i catalytic subunit. | the catalytic subunit of rabbit skeletal muscle cyclic amp-dependent protein kinase i can catalyze self-phosphorylation. the autophosphorylation reaction uses atp as the phosphoryl donor, requires mg2+, and is inhibited by polyarginine. prior treatment of the catalytic subunit with escherichia coli alkaline phosphatase in the presence of bovine serum albumin greatly enhances the autophosphorylation of the subunit. the protein-bound phosphate is stable in acid but labile in base. incubation of th ... | 1978 | 212418 |
| escherichia coli pyruvate dehydrogenase complex. site coupling in electron and acetyl group transfer pathways. | | 1978 | 212420 |
| a novel phosphodiesterase from aspergillus niger and its application to the study of membrane-derived oligosaccharides and other glycerol-containing biopolymers. | a novel phosphodiesterase has been found in commercially available extracts of aspergillus niger and has been partially purified by fractionation with acetone and chromatography on carboxymethylcellulose. the enzyme attacks glycerophosphodiester bonds with the liberation of free glycerol only. the synthetic substrate glucose 6-phospho-sn-1'(3')-glycerol is hydrolyzed with production of equivalent amounts of free glycerol and glucose 6-phosphate. similarly, the enzymic hydrolysis of sn-glycero-3- ... | 1978 | 212432 |
| reconstitution of escherichia coli succinoxidase from soluble components. | 1. the membrane-bound succinoxidase of escherichia coli was fractionated with deoxycholate into three soluble components, viz. succinate dehydrogenase.cytochrome b1 complex, cytochrome oxidase complex, and a factor identified as a phospholipid-containing component. 2. the dehydrogenase and cytochrome oxidase complexes were partially purified by filtration on amicon membranes, sepharose 4b chromatography, and sucrose gradient centrifugation. 3. reconstitution of membranous succinoxidase, which ca ... | 1978 | 212441 |
| in vitro synthesis of double-stranded dna from the kilham rat virus single-stranded dna genome. | double-stranded, full-length linear dna was synthesized in vitro by using single-stranded linear dna as a self-priming template from the parvovirus kilham rat virus and escherichia coli dna polymerase "large fragment" as the polymerizing enzyme. to ascertain the order of the synthesis of the cleavage fragments and to assess the accuracy of the in vitro synthesis, restriction endonuclease cleavage sites with known recognition sequences were mapped on the dna. comparing the cleavage pattern of the ... | 1978 | 212593 |
| cell-free synthesis of simian virus 40 t-antigens. | polyacrylamide gel electrophoresis and tryptic peptide fingerprint analysis of the proteins made in a cell-free system derived from l-cells and immunoprecipitated with simian virus 40 (sv40) anti-t serum demonstrated that both sv40 large-t and small-t antigens are synthesized in vitro in response to mrna isolated from productively infected cv1 cells. sucrose density centrifugation in gradients containing 85% formamide showed that the mrna's for both forms of t-antigen sediment at about 17.5s, wi ... | 1978 | 212600 |
| nucleotide sequences related to the transforming gene of avian sarcoma virus are present in dna of uninfected vertebrates. | we have detected nucleotide sequences related to the transforming gene of avian sarcoma vius (asv) in the dna of uninfected vertebrates. purified radioactive dna (cdnasarc) complementary to most of all of the gene (src) required for transformation of fibroblasts by asv was annealed with dna from a variety of normal species. under conditions that facilitate pairing of partially matched nucleotide sequences (1.5 m nacl, 59 degrees), cdnasarc formed duplexes with chicken, human, calf, mouse, and sa ... | 1978 | 212733 |
| 6-beta-bromopenicillanic acid, a potent beta-lactamase inhibitor. | 6-beta-bromopenicillanic acid, which arises from the epimerization of 6-alpha-bromopenicillanic acid in aqueous solution or from hydrogenation of 6,6-dibromopenicillanic acid, is a powerful, irreversible, active-site-directed inhibitor of several typical beta-lactamases (penicillinase; penicillin amido-beta-lactamhydrolase, ec 3.5.2.6); 6-alpha-bromopenicillanic acid, being completely inhibited at less than micromolar concentrations through what is probably a 1:1 interaction. the b. licheniformi ... | 1978 | 212736 |
| mechanism of the in vitro breakdown of guanosine 5'-diphosphate 3'-diphosphate in escherichia coli. | degradation of guanosine tetraphosphate (ppgpp) involves an enzyme associated with the ribosomal fraction from spot+ strains of escherichia coli. double-label experiments with pp[3h]gpp, pp[3h]gpp, or pp[3h]gpp as substrate strongly suggest that ppg is the degradation product and that the enzyme releases two phosphates coordinately from the 3' position of ppgpp. in the absence of pppa this reaction proceeds in an uncoupled fashion, yielding ppg and ppi, but in the presence of pppa the decay is c ... | 1978 | 212739 |
| multiple functions of thioredoxins. | reduced thioredoxins from microbial and plant cells, both of cytoplasmic or chloroplast origin, are interchangeable in stimulating such diverse enzyme activities as ribonucleoside diphosphate reductase (e. coli), paps sulfotransferase (synechococcus), and fructose-1,6-bis-phosphatase (from spinach) in vitro. it is suggested that reduced thioredoxins are unspecific, multifunctional cellular proteins while in contrast the oxidized froms require specific enzymes for their reduction. | 1978 | 212888 |
| [diarrhea of the newborn animal: nature and mechanism of action of enteropathogenic escherichia coli in the calf and piglet]. | the present knowledge of the enteropathogenic characteristics of escherichia coli (adhesion and toxinogenesis) is reviewed in the calf, and compared with piglet data. a pathogenic model of e. coli diarrhoea in the calf is proposed, taking into account the electromyographic, bacteriologic and physiologic data. | 1978 | 213007 |
| fluorescence and chemical studies on the interaction of escherichia coli dna-binding protein with single-stranded dna. | nanosecond and steady-state fluorescence spectoscopy were used to probe the environment of the tryptophan residues of escherichia coli dna-binding protein. a spectral shift and a change in quantum yield of the protein upon binding to dna or oligonucleotides indicate that the tryptophan residues are near or at the dna binding site. the observation of two excited-state lifetimes of the protein indicates that there is heterogeneity in the microenvironments of these tryptophan residues. the "short-l ... | 1978 | 213102 |
| specific association of two homologous dna-binding proteins to the native 30-s ribosomal subunits of escherichia coli. | the native 30-s ribosomal subunits from escherichia coli are shown to be associated with two proteins which are different from the known ribosome-associated and ribosomal proteins. neither protein is foune on native 50-s subunits or on intact ribosomes in the cell extract. the purified proteins re-bind in vitro to free 30-s subunits, but do not bind to either free 50-s subunits or intact ribosomes. the proteins, denoted ns1 and ns2, have been purified and characterized. both proteins showed the ... | 1978 | 213117 |
| glycoproteins of natural origin with an affinity for hepatitis b surface antigen. | sera from certain animal species contain a substance(s) which binds hepatitis b surface antigen. the hepatitis b binding substance found in animals is not antibody, but appears to be a glycoprotein which reacted with antigen-coated beads and produced a "false positive" test for antibody. this glycoprotein could be selectively and quantitatively removed by reaction with purified hepatitis b surface antigen and centrifugation. pili fractions isolated from neisseria gonorrhoeae and escherichia coli ... | 1978 | 213390 |
| changes in composition of envelope proteins in adenylate cyclase- or cyclic amp receptor protein-deficient mutants of escherichia coli. | synthesis of several envelope proteins in escherichia coli k-12 is regulated by cyclic amp and cyclic amp receptor protein. | 1978 | 213421 |
| superoxide radical and the oxygen enhancement of the toxicity of paraquat in escherichia coli. | | 1978 | 213429 |
| amino acid sequence of a peptide containing an essential cysteine residue of escherichia coli gmp synthetase. | the amino acid sequence of a 51-residue tryptic peptide of citraconylated [1-14c]carboxamidomethyl-labeled escherichia coli gmp synthetase was determined by sequenator analyses of the intact peptide and fragments obtained by cleavage of the peptide with cyanogen bromide, trypsin, and staphylcoccus aureus strain v8 protease. the cysteine residue of this peptide fragment is essential for glutamine-dependent gmp synthesis activity and is implicated in formation of a hypothetical covalent glutamyl-e ... | 1978 | 213434 |
| enhancement of neutrophil chemotaxis and alteration of levels of cellular cyclic nucleotides by levamisole. | levamisole, an antihelminthic agent reported to enhance nonspecifically various parameters of the immune response, was examined for its effect on chemotaxis of human neutrophils and on levels of cellular cyclic nucleotides. this agent was found, in most instances, to enhance chemotactic responses of neutrophils to a bacterial chemotactic factor derived from escherichia coli. at similar concentrations, levamisole produced increases in levels of guanosine 3':5'-cyclic phosphate in neutrophils. in ... | 1978 | 213494 |
| the cyclic 3',5'-adenosine monophosphate receptor protein and regulation of cyclic 3',5'-adenosine monophosphate synthesis in escherichia coli. | rates of synthesis of cyclic 3',5'-adenosine monophosphate (camp) were measured in cultures of escherichia coli aerating without a carbon source. this technique provides a representative measure of adenylate cyclase activity in the absence of inhibition caused by transport of the carbon source. adenylate cyclase activity was found to vary more than 20-fold depending on the carbon source that had been available during growth. synthesis of camp in cells aerating in the absence of the carbon source ... | 1978 | 213702 |
| effect of guanosine 5'-diphosphate 3'-diphosphate and related nucleoside polyphosphates on induction of tryptophanase and beta-galactosidase in permeabilized cells of escherichia coli. | exogenous addition of guanosine and adenosine 5'-(mono, di and tri) phosphate 3'-diphosphates (pppgpp, ppgpp, pgpp, pppapp, ppapp and papp) stimulated the synthesis of tryptophanase and beta-galactosidase in permeabilized cells of escherichia coli. from the results obtained with ppgpp and pppapp, this effect appeared to be at a transcriptional level and depended greatly on the growth condition; the largest effect was observed in cells under shiftdown or grown on poor enrgy source. ppgpp and pppa ... | 1978 | 214051 |
| isolation of the membranes of an enterotoxigenic strain of escherichia coli and distribution of enterotoxin activity in different subcellular fractions. | the intracellular localization of enterotoxin in escherichia coli ap1, a strain of porcine origin which produces high levels of heat-labile, but no heat-stable enterotoxin, has been examined. the cytoplasmic and outer membranes of this strain both contained enterotoxin activity, while the membranes isolated from a serologically related non-enterotoxigenic strain (e. coli ap2) also of porcine origin, did not show enterotoxin activity. the periplasmic fraction isolated from the enterotoxigenic str ... | 1978 | 214115 |
| nucleosidediphosphate kinase of escherichia coli, a periplasmic enzyme. | the atp-adp exchange activity previously described in a membrane farction of escherichia coli appeared after a cold osmotic shock according to neu and heppel ((1965) j. biol. chem. 240, 3685--3692) in the shock fluid. membranes derived from shocked cells had no activity. the enzyme responsible for this activity has been purified 125-fold and catalyzed the transfer of a phosphoryl radical from ribonucleosidetriphosphates (ntps) to ribonucleosidediphosphates (ndps); this is, therefore, a non-speci ... | 1978 | 214126 |
| [effect of mutations in regulatory genes for alkaline phosphatase on the phosphohydrolase spectrum of e. coli periplasm]. | the isoform spectra of alkaline and acid phosphatase, pyrophosphataes, and atpase in periplasm of e. coli were studied using electrophoresis in polyacrylamide gel with subsequent development of zimograms directly in the gel. wild strains and mutants on 4 regulatory genes of alkaline phosphatase were analyzed. mutations in regulatory genes were shown to influence the amount of each of the 3 isoforms of alkaline phosphatase and also the spectra of other phosphohydrolases. | 1978 | 214171 |
| [mechanism of the antimicrobial effect of myeloperoxidase. adsorption of the enzyme onto the surface of escherichia coli (immunofluorescent study)]. | | 1978 | 214280 |
| [identification of ecock restriction endonucleases in escherichia coli ck cells]. | | 1978 | 214281 |
| effects of altered rho gene product on the expression of the escherichia coli histidine operon. | an altered rho gene product affects expression of the his operon of escherichia coli. the effect is greater for the operator proximal portion of the his operon than for the operator distal portion. this "rho effect" appears to be independent of the site of action of hist-altered histidyl-trna. | 1978 | 214421 |
| regulation of lac operon expression: reappraisal of the theory of catabolite repression. | the physiological state of escherichia coli with respect to (permanent) catabolite repression was assessed by measuring the steady-state level of beta-galactosidase in induced or in constitutive cells under a variety of growth conditions. four results were obtained. (i) catabolite repression had a major effect on fully induced or constitutive expression of the lac gene, and the magnitude of this effect was found to be dependent on the promoter structure; cells with a wild-type lac promoter showe ... | 1978 | 214424 |
| the turnover of trnas microinjected into animal cells. | red cell-mediated microinjection has been used to study trna turnover in sv3t3 mouse cells and tc7 cells, an african green monkey kidney line. the turnover of endogenous trna, measured by labeling with 3h-methionine, was first-order with half-lives of approximately one day in sv3t3 and two days in tc7 cells. 32ptrna isolated from e. coli or tc7 cells turned over at the same rate as endogenous trna when injected into either sv3t3 or tc7 cells. this demonstrates that cellular processes, not proper ... | 1978 | 214762 |
| escherichia coli dna topoisomerase i catalyzed linking of single-stranded rings of complementary base sequences. | eco dna topoisomerase i (e. coli omega protein) has been observed to catalyze the formation of double-stranded, covalently closed dna from complementary single-stranded dna rings, a novel reaction which is topologically forbidden without the enzyme-catalyzed breakage and rejoining of dna backbone bonds. incubation of a mixture of single-stranded pm2 dna rings of complementary base sequences with omega yields a species with a sedimentation coefficient in an alkaline medium characteristic of a cov ... | 1978 | 214763 |
| rapid intramolecular coupling of active sites in the pyruvate dehydrogenase complex of escherichia coli: mechanism for rate enhancement in a multimeric structure. | in the absence of coa and presence of pyruvate, the lipoic acid residues covalently bound to the lipoate acetyltransferase core component (acetyl-coa:dihydrolipoate s-acetyltransferase, ec 2.3.1.12) of the pyruvate dehydrogenase multienzyme complex of escherichia coli become reductively acetylated. a study of a series of reassembled complexes varying only in their content of pyruvate decarboxylase [pyruvate:lipoate-oxidoreductase (decarboxylating and acceptor-acetylating) ec 1.2.4.1] showed that ... | 1978 | 214786 |
| results of a five-year study of the curative effect of double stranded ribonucleic acid in viral dermatoses and eye diseases. | double stranded rna obtained from non-permissive e. coli cells infected with f2-phage was tested in 5 hospitals in viral dermtoses such as herpes simplex recidivans, herpes zoster, male genikeratonconjunctivitis herpetica and conjunctivitis lignosa. the results of clinical tests indicate that the preparation of phage double stranded rna applied topically is harmless for man and has, in the majority of cases, a beneficial effect in the disease. this conclusion was based on the judgment of physici ... | 1978 | 215011 |
| subunit dissociation in the allosteric regulation of glycerol kinase from escherichia coli. 1. kinetic evidence. | | 1978 | 215194 |
| subunit dissociation in the allosteric regulation of glycerol kinase from escherichia coli. 2. physical evidence. | the dependence of the molecular weight of glycerol kinase on enzyme concentration and on binding of fructose 1,6-bisphosphate has been examined by velocity sedimentation, gel filtration, and polyacrylamide gel electrophoresis. the sedimentation coefficient and stokes radius decrease as a consequence of dilution in a manner consistent with dissociation into half-molecules, with limiting values suggesting molecular weights of about 218,000 and 136,000 for the associated and dissociated species, re ... | 1978 | 215195 |
| kinetic mechanism of escherichia coli carbamoyl-phosphate synthetase. | the kinetic mechanism of escherichia coli carbamoyl-phosphate synthetase has been determined at ph 7.5, 25 degrees c. with ammonia as the nitrogen source, the initial velocity and product inhibition patterns are consistent with the ordered addition of mgatp, hco3-, and nh3. phosphate is then released and the second mgatp adds to the enzyme, which is followed by the ordered release of mgadp, carbamoyl phosphate, and mgadp. with glutamine as the ammonia donor, the patterns are consistent with a tw ... | 1978 | 215204 |
| phospho-n-acetylmuramoyl-pentapeptide-transferase of escherichia coli k12. properties of the membrane-bound and the extracted and partially purified enzyme. | phospho-n-acetylmuramoyl-pentapeptide-transferase (udp-n-acetyl-muramoyl-l-alanyl-d-gamma-glutamyl-l-lysyl-d-alanyl-d-alanine:undecaprenoid-alcohol-phosphate-phospho-n-acetylmuramoyl-pentapeptide-transferase, ec 2.7.8.13) was solubilized by repeated freezing and thawing of crude envelopes of escherichia coli k12. the solubilized enzyme was partially purified by gel filtration and ion-exchange chromatography. this preparation contained small amounts of phosphatidylethanolamine, phosphatidylglycer ... | 1978 | 215212 |
| [quaternary structure and proteolysis of the polynucleotide phosphorylase from c. perfringens]. | this report describes structural studies on purified polynucleotide phosphorylase from c. perfringens. a method is described for the purification of the enzyme which yields a product equivalent in activity to the native polynucleotide phosphorylase from e. coli. these studies revealed a molecular heterogeneity arising from successive stages of proteolysis, to which this enzyme is especially sensitive; unusally, the enzyme is obtained as a mixture of variable proportions of the native and proteol ... | 1978 | 215236 |
| determination of the rates of synthesis and degradation of adenosine 3',5'-cyclic monophosphate in escherichia coli crp- and crp+ strains. | we have developed a method for estimating the rates of synthesis and degradation of adenosine 3',5'-cyclic monophosphate (camp) in escherichia coli during balanced growth. applying this method, we have found that an e. coli crp- mutant 5333 (deficient for camp receptor protein) synthesizes camp about 25 times faster than does its crp+ parent 1100. this accounts for the abnormally high intracellular and extracellular camp accumulation in 5333. | 1978 | 215288 |
| the free radical in ribonucleotide reductase from e. coli. | protein b2, one of the subunits of ribonucleotide reductase from escherichia coli, contains a stable free radical. it is characterized by a doublet e.p.r. signal centered around g = 2.0047 and a sharp peak at 410 nm in the optical spectrum. the radical has been assigned to a tyrosyl residue in the protein with its spin density delocalized over the aromatic ring. protein b2 also contains two antiferromagnetically-coupled high-spin iron(iii) atoms, which stabilize the free radical. protein b1, the ... | 1977 | 215392 |
| preparation of the dna-binding protein hu from escherichia coli by immuno-affinity chromatography. | | 1978 | 215459 |
| primary structures of two homologous ribosome-associated dna-binding proteins of escherichia coli. | | 1978 | 215461 |
| effect of escherichia coli heat-stable enterotoxin on cyclic gmp levels in mouse intestine. | partially purified heat-stable enterotoxin obtained from escherichia coli strain f11/p155 caused an accumulation of cyclic gmp in the intestines of 8-day-old mice. | 1978 | 215544 |
| comparative studies of five heat-labile toxic products of escherichia coli. | five heat-labile, partially purified toxic products of escherichia coli were distinguished by isoelectric focusing, molecular weight, and neutralization with homologous and heterologous antisera. only two affected the morphology of y-1 cells, induced fluid accumulation in rabbit ileal loops, and stimulated production of cyclic amp in vero cells; these two did not cross-neutralize and only one showed cross-neutralization with cholera antitoxin. the remaining three products were cytotoxic for vero ... | 1978 | 215549 |
| escherichia coli mutants defective in dipeptidyl carboxypeptidase. | two independent mutants of escherichia coli deficient in dipeptidyl carboxypeptidase activity (dep-) were isolated after mutagenesis with ethyl methanesulfonate. mating experiments and introduction of specific episomes indicated that the responsible gene was located at approximately 27--31 min on the e. coli chromosome. the dep- mutants differed from the parental strain in their inability to grow with n-acetylalanylalanylalanine as the sole nitrogen source. revertants selected for growth on this ... | 1978 | 216006 |
| construction of bacterial plasmids that contain the nucleotide sequence for bovine corticotropin-beta-lipotropin precursor. | mrna that encodes the common peptide precursor for the hormones corticotropin and beta-lipotropin was purified from the neurointermediate lobe of bovine pituitaries, and double-stranded cdna species synthesized from this template were cloned in escherichia coli x1776 by inserting them into the pst i endonuclease cleavage site of the pbr322 plasmid using poly(dg)poly(dc) homopolymeric extensions. certain of the cloned cdna inserts contain nucleotides corresponding to the complete amino acid seque ... | 1978 | 216007 |
| radiation-induced damage in escherichia coli b: the effect of superoxide radicals and molecular oxygen. | | 1978 | 216051 |
| high levels of microbial contamination of vegetables irrigated with wastewater by the drip method. | the public health aspects of the use of wastewater in agriculture and the effects of the drip irrigation method on the contamination of vegetables were studied. the method used was to simulate enteric microorganisms' dissemination by contaminated irrigation water in the field. the vegetables were irrigated with an effluent inoculated with a high titer of traceable microorganisms: poliovirus vaccine and a drug-resistant escherichia coli. the dissemination of the marker organisms in the field was ... | 1978 | 216306 |
| intrasubunit nucleotide binding in ribonucleic acid polymerase. | 1. periodate oxidation of the ribose ring was used to synthesize derivatives of nucleoside triphosphates. 2. these oxidized nucleoside triphosphates. 2. these oxidized nucleoside triphosphates are competitive inhibitors of rna polymerase. 3. on incubation, together with nabh4, these oxidized labelled nucleotides are covalently bound to escherichia coli rna polymerase. 4. nucleoside triphosphate substrates decrease the extent of labelling. 5. a lysine residue in an alpha-subunit is labelled. 6. t ... | 1978 | 216347 |
| [biochemical characterization of a pnc mutation of the nad biosynthetic pathway in e. coli b/r]. | | 1978 | 216381 |
| biosynthesis of enterochelin in escherichia coli k-12: separation of the polypeptides coded for by the entd, e, f and g genes. | four enzymic components, coded for by the entd, ente, entf and entg genes, involved in the biosynthesis of enterochelin from 2,3-dihydroxybenzoate have been separated from cell extracts of mutant strains of escherichia coli k-12. the starting material for fractionation of the e, f and g components was a cell extract of an entd mutant strain, which yielded the e, f and g enzymic components uncontaminated by a functional d component. the d component was isolated from cell extracts of an ente mutan ... | 1979 | 216414 |
| preferential charging of trna-met-f in escherichia coli k12. | the charging of trna-met-f and trna-met-m in vivo and in vitro and initiation of polysomes during methionine limitation were studied in two strains of escherichia coli k12. in the wild-type strain the distribution of polysomes as well as the kinetic parameters of methionyl-trna synthetase indicate preferential acylation of trna-met-f. this preferential charging of trnam-et-f does not take place in a mutant strain which is also defective in initiation of polysomes during methionine limitation. | 1978 | 216545 |
| photolabile and paramagnetic derivatives of the nucleoside x and of escherichia coli trnaphe. | the synthesis of n3-[3-l-(5-azido-2-nitrobenzamido)-3-carboxypropyl]uridine (4b) and n3-[3-carboxy-3-l-(2,2,5,5-tetramethyl-3-pyrroline-3-carbonylamino)propyl]uridine npyr-oxyl (4c) starting from the nucleoside x (4a) and the appropriate n-hydroxysuccinimide ester 1 or 2 is described. after acylation of trnaphe from e. coli (5a) with 1 or 2, the photolabile trnaphe derivative 5b and the paramagnetic trnaphe derivative 5c could be isolated. the position of modification in the polynucleotide chain ... | 1978 | 216614 |
| determination of 6-methyladenine in dna by high-performance liquid chromatography. | a method for the determination of 6-methyladenine (6ma) by high-performance liquid chromatography (hplc) has been developed. dna bases were separated by using the strong cation-exchange resin zipax scx. purine bases were obtained by hydrolysis and dialysis of dna and analysed by hplc. 6ma in dna from escherichia coli was determined by the proposed method. it is suggested that the method could be applicable to analyses of 6ma from other biological sources. | 1979 | 216706 |
| eukaryotic ribosomal proteins stimulate escherichia coli stringent factor to synthesize guanosine 5'-diphosphate, 3'-diphosphate (ppgpp) and guanosine 5'-triphosphate, 3'-diphosphate (ppgpp). | when supplemented with escherichia coli stringent factor, 80s ribosomes from various sources failed to support guanosine tetra- and pentaphosphate ((p)ppgpp) synthesis. in contrast, ribosomal proteins from 80s, 60s or 40s particles (mouse embryos, rabbit reticulocytes) crossreacted with the e. coli stringent factor. significant stimulation of (p)ppgpp synthesis was achieved with a concentration as low as 5 micrograms of ribosomal proteins/ml. these observations may provide additional crtieria to ... | 1978 | 216901 |
| molecular cloning of polyoma virus dna in escherichia coli: plasmid vector system. | a series of recombinant plasmids containing polyoma virus (py) dna were constructed, and their biological activity was evaluated in mice and in cultured mouse cells. while all of the recombinants studied contain the complete, potentially infectious viral dna, in no case was the intact recombinant py-plasmid dna, or live escherichia coli containing the recombinant plasmids, capable of inducing py infection of mice, either by feeding or by parenteral injection. | 1979 | 217087 |
| molecular cloning of polyoma virus dna in escherichia coli: lambda phage vector system. | the biological activity of recombinant phage and recombinant phage dna containing monomeric or dimeric polyoma dna inserts was examined in mice and cultured mouse cells. recombinant preparations containing a single copy of viral dna were invariably noninfectious; molecules containing a dimeric polyoma dna insert were at least seven orders of magnitude less infectious than polyoma virions after parenteral inoculation. no infection was detected with any recombinant preparation after oral administr ... | 1979 | 217088 |
| purification and properties of nitrite reductase from escherichia coli k12. | nadh-nitrite oxidoreductase (ec 1.6.4) was purified to better than 95% homogeneity from batch cultures of escherichia coli strain or75ch15, which is partially constitutive for nitrite reductase synthesis. yields of purified enzyme were low, mainly because of a large loss of activity during chromatography on deae-cellulose. the quantitative separation of cytochrome c-552 from nitrite reductase activity resulted in an increase in the specific activity of the enzyme: this cytochrome is not therefor ... | 1978 | 217342 |
| activation of nitrite reductase from escherichia coli k12 by oxidized nicotinamide-adenine dinucleotide. | nitrite reductase from escherichia coli k12 requires the presence of nad+, one of the products of the reduction of no2-by nadh, for full activity. the effect is observed with both crude extracts and purified enzyme. nad+ also acts as a product inhibitor at high concentrations, and plots of initial rate against nad+ concentration are bell-shaped. the maximum occurs at about 1 mm-nad+, but increases with increasing nadh concentration. in the presence of 1 mm-nad+ and saturating no2-(2mm) the micha ... | 1978 | 217343 |
| cooperative binding to dna of catabolite activator protein of escherichia coli. | | 1979 | 217408 |
| the regulatory effects of growth rate and cyclic amp levels on carbon catabolism and respiration in escherichia coli k-12. | cyclic amp levels in glucose and succinate-limited and ammonia-limited glucose-containing continuous cultures of escherichia coli were measured at different bacterial growth rates. intracellular cyclic amp concentrations were fairly constant (about 5 micrometer) at all dilution rates used when glucose was limiting. in ammonia-limited glucose cultures the cyclic amp content was much lower (about 0.3 micrometer). in succinate-limited cultures cyclic amp levels fell from 2.7 to 0.8 micrometer as di ... | 1979 | 217449 |
| [aminoglycoside-3'-phosphotransferase i from aminoglycoside-polyresistant strain e. coli 182]. | an aminoglycoside-3'-phosphotransferase i catalyzing phosphorylation of some aminoglycoside antibiotics with the 3'-hydroxyl group has been purified from the cells of aminoglycoside resistant strain e. coli 182 by competitive affinity chromatography on neomycin-sepharose and gel-filtration on sephadex g-100. the product of enzymatic phosphorylation of kanamycin a was isolated and identified as kanamycin-3'-phosphate by nmr, thin-layer chromatography and chemical characterization. the kinetic pro ... | 1978 | 217451 |
| construction of an escherichia coli strain which excretes abnormally large amounts of adenosine 3',5'-cyclic monophosphate. | it has previously been shown that an escherichia coli crp- strain 5333 accumulates abnormally large amounts of adenosine 3',5'-cyclic monophosphate (camp). using p1 transduction, the crp- character was transferred to e. coli crookes strain which is deficient for camp phophodiesterase (cpd-). the resulting strain hy22 (crp-, cpd-) accumulates greater amounts of camp both intracellularly and extracellularly than does 5333. in glucose minimal medium, an hy22 cell accumulates 100 times more camp int ... | 1978 | 217515 |
| evidence that the hypothalamus mediates endotoxin stimulation of adrenocorticotropic hormone secretion. | the site of action of escherichia coli endotoxin in inducing acth secretion was studied in vivo and in vitro. hypophysectomized rats, bearing two to three transplanted pituitaries under the kidney capsule and "primed" with exogenous acth, responded to 2.0-7.5 microgram/100 g bw ip or iv endotoxin with a several-fold increase of plasma corticosterone. this response was markedly reduced by hypothalamic lesions and completely abolished by removing the entire forebrain. endotoxin added directly to c ... | 1978 | 217611 |
| myeloperoxidase, hydrogen peroxide, chloride antimicrobial system: nitrogen-chlorine derivatives of bacterial components in bactericidal action against escherichia coli. | in the presence of escherichia coli, myeloperoxidase-catalyzed oxidation of chloride ion resulted in formation of long-lived chloramine and/or chloramide derivatives of bacterial components. the same amount of these nitrogen-chlorine (n-cl) derivatives was obtained with either hypochlorous acid (hocl) or the myeloperoxidase system, indicating that myeloperoxidase catalyzed the oxidation of chloride to hocl. identical killing was obtained with hocl or the myeloperoxidase system. about 30 to 50% o ... | 1979 | 217834 |
| mecillinam in urinary tract infections and in septicaemia. | the clinical and bacteriological efficacy as well as the tolerance of mecillinam, a new beta-lactam antibiotic, administered parenterally in a dose of 40 mg/kg body weight, was investigated in 21 hospitalized patients with urinary tract infections or septicaemia. success, defined as eradication of infecting organisms two to five days after treatment, was found in eight of 16 patients with urinary tract infections. persistence of the original pathogen after treatment was seen in four patients, al ... | 1979 | 217836 |
| antigens in penicillin allergy. iii. antigen and antibody levels in mice treated with pure and contaminated penicillins. | using a radioimmunoassay, it was shown that commercially available ampicillin preparations often contain penicilloylated high molecular weight impurities. these possess immunological activities and stimulate penicilloyl-specific antibody formation in mice treated according to a therapeutic schedule. using purified and experimentally contaminated preparations it was also found that exposure of the animals to escherichia coli and bordetella pertussis bacteria could increase the antibody formation ... | 1979 | 217840 |
| transport of alpha-p-nitrophenylgalactoside by the lactose carrier of escherichia coli. | alpha-p-nitrophenylgalactoside was found to be accumulated by the lactose transport-system of escherichia coli. this fact may help to resolve the differences in the reported number of sugar binding sites of the lactose transport protein in nonenergized and energized membrane vesicles. | 1979 | 217863 |
| lipid and lipopolysaccharide composition of escherichia coli surface-altered mutants selected for resistance to levallorphan, tetracaine, and polymyxin. | certain mutants of escherichia coli with an altered permeability barrier have an essentially normal lipopolysaccharide, fatty acid, and phospholipid content, with a slight increase in the membrane protein:lipid ratio. the phospholipid metabolism of the lev and tec strains shows an abnormal response to growth in the selective agents levallorphan and tetracaine, respectively. | 1979 | 217864 |
| high and selective resistance to mecillinam in adenylate cyclase-deficient or cyclic adenosine 3',5'-monophosphate receptor protein-deficient mutants of escherichia coli. | adenylate cyclase-deficient (cya) mutants of escherichia coli k-12 were selectively and highly resistant to mecillinam (fl1060) among several beta-lactam antibiotics in the absence of cyclic adenosine 3',5'-monophosphate (camp). they became sensitive to the drug in the presence of camp. also, camp receptor protein-negative (crp) mutants, with the exception of strain 5333, were highly resistant to mecillinam in the presence and in the absence of camp. mecillinam exerted two distinct and sequentia ... | 1979 | 217866 |
| diglyceride kinase mutants of escherichia coli: inner membrane association of 1,2-diglyceride and its relation to synthesis of membrane-derived oligosaccharides. | mutants of escherichia coli defective in diglyceride kinase contain 10 to 20 times more sn-1,2-diglyceride than normal cells. this material constitutes about 8% of the total lipid in such strains. we now report that this excess diglyceride is recovered in the particulate fraction, primarily in association with the inner, cytoplasmic membrane. the diglyceride kinase of wild-type cells was recovered in the same inner membrane fractions. the conditions employed for the preparation of the membranes ... | 1979 | 217867 |
| [action of cyclic adenosine monophosphate on the spleen antibody--forming cells of rabbits immunized with escherichia coli]. | cyclic adenosine monophosphate (camp) parenterally injected to rabbits (immunized intraperitoneally with thymus-independent antigen of killed e. coli 0127/545) during january--april inhibited production of antibody-forming cells (afc) in the spleen of these animals, and during may--june it increased the afc count. both the stimulating and inhibitory effect of camp was associated with the administration of the same doses of 25--250 microgram/kg. the nature of the camp effect on the production of ... | 1978 | 218404 |
| low trimethoprim susceptibility of anaerobic bacteria due to insensitive dihydrofolate reductases. | all the 28 bacteroides fragilis strains investigated were susceptible to sulfamethoxazole (minimal inhibitory concentration < 16 mug/ml) and resistant to trimethoprim (tmp; minimal inhibitory concentration > 4 mug/ml). synergism between sulfamethoxazole and tmp was present in all strains at a ratio of 1:1. the few clostridia investigated proved more resistant to both compounds. dihydrofolate reductases from b. fragilis, c. perfringens, and some other anaerobic species were isolated. inhibition p ... | 1979 | 218496 |
| mechanism of aminoglycoside antibiotic resistance in anaerobic bacteria: clostridium perfringens and bacteroides fragilis. | cell-free amino acid incorporation using ribosomes from strains of either clostridium perfringens or bacteroides fragilis was shown to be susceptible to inhibition by streptomycin and gentamicin. ribosomes bound dihydrostreptomycin as effectively as ribosomes from escherichia coli. no inactivation of streptomycin or gentamicin was detected by cell extracts of either anaerobic bacterial species. b. fragilis, grown without added hemin, menadione, and fumarate, and c. perfringens did not show any t ... | 1979 | 218500 |
| immunochemical analysis of membrane vesicles from escherichia coli. | membrane vesicles isolated from escherichia coli ml 308--225 have been analyzed by crossed immunoelectrophoresis, and immunoprecipitates corresponding to the following cellular components have been identified: atpase (ec 3.6.1,3), two or three nadh dehydrogenases (ec 1.6.99.3), d-lactate dehydrogenase (ec 1.1.1.27), glutamate dehydrogenase (ec 1.4.1.4), dihydro-orotate dehydrogenase (ec 1.3.3.1), 6-phosphogluconate dehydrogenase (ec 1.1.1.43), polynucleotide phosphorylase (ec 2.3.7.8), beta-gala ... | 1979 | 218620 |
| antigenic architecture of membrane vesicles from escherichia coli. | the antigenic architecture of membrane vesicles prepared from escherichia coli ml 308--225 has been studied using crossed immunoelectrophoresis. progressive immunoadsorption experiments conducted with control vesicles and with physically disrupted vesicles were used to monitor and quantitate the expression of 14 different immunogens. eleven immunogens, including nadh dehydrogenase (ec 1.6.33.3), d-lactate dehydrogenase (ec 1.1.1.27), dihydro-orotate dehydrogenase (ec 1.3.3.1), 6-phosphogluconate ... | 1979 | 218621 |
| cross-linking of the camp receptor protein of escherichia coli by o-phenylenedimaleimide as a probe of conformation. | reaction of the camp (cyclic adenosine 3'--5'-monophosphate) receptor protein (crp) of escherichia coli with the bifunctional reagent o-phenylenedimaleimide (opdm) results in the cross-linking of the two subunits of a crp protomer. in the presence of camp the rate of cross-linking increases. crp modified with opdm retains [3h]camp binding activity but loses [3h]d(i-c)n binding activity. proteolysis of cross-linked crp gives distinct sodium dodecyl sulfate-polyacrylamide gel electrophoretic patte ... | 1979 | 218622 |
| mechanism of carbamoyl-phosphate synthetase. binding of atp by the rat-liver mitochondrial enzyme. | this paper demonstrates, by pulse-chase techniques, the binding to rat liver mitochondrial carbamoyl phosphate synthetase of the atp molecule (atpb) which transfers its gamma-phosphoryl group to carbamoyl phosphate. this bound aptb can react with nh3, hco-3 and atp (see below) to produce carbamoyl phosphate before it exchanges with free atp. mg2+ and n-acetylglutamate, but not nh3 or hco-3, are required for this binding; the amount bound depends on the concentration of atp (kapp = 10--30 microns ... | 1979 | 218811 |
| a dna-unwinding enzyme induced in bacteriophage-t4-infected escherichia coli cells. | a single-stranded dna-dependent atp gamma-phosphohydrolase of mr 56000 induced after infection of escherichia coli cells with bacteriophage t4, probably the atpase dependent on gene dda of the phage, was isolated. studies on the enzyme show that in the presence of atp and m2+ ions it is capable of dissociating partially double-stranded fd bacteriophage dna into the single strands and that some 3000 enzyme copies are required to unwind the 6400-nucleotides-long dna. unwinding is inhibited by redu ... | 1979 | 218815 |
| diglyceride kinase from escherichia coli. purification in organic solvent and some properties of the enzyme. | the diglyceride kinase activity of membranes from escherichia coli was extracted into acidic butan-1-ol. the enzyme was purified in organic solvent by precipitation at -20 degrees c, chromatography on deae-cellulose and repeated chromatography on sephadex lh-60. the final 1460-fold purified enzyme preparation gave a single protein band upon isoelectric focusing in the presence of triton x-100 (pi, 4.0) and upon polyacrylamide-gel electrophoresis in the presence of sodium dodecylsulphate. the lat ... | 1979 | 218816 |
| replication of m13 duplex dna in soluble extracts of escherichia coli. effect of helix-destabilising proteins. | soluble extracts of m13-am5-infected escherichia coli cells can carry out multiple rounds of m13 duplex dna replication when supplemented with helix-destabilising protein of e. coli. similarly addition of the helix-destabilising m13 gene 5 protein in low concentrations (up to 30 micrograms/ml) stimulates the replication of double-stranded m13 dna. in contrast, higher concentrations of gene 5 protein (but not of e. coli helix-destabilising protein) cause a preferential inhibition of complementary ... | 1979 | 218817 |
| the effect of escherichia coli on human spermatozoal cyclic adenosine 3':5'-monophosphate. | | 1979 | 218851 |
| the escherichia coli adenylate cyclase complex: activation by phosphoenolpyruvate. | a model for the regulation of the activity of escherichia coli adenylate cyclase is presented. it is proposed that enzyme i of the phosphoenolpyruvate:sugar phosphotransferase system (pts) interacts in a regulatory sense with the catalytic unit of adenylate cyclase. the phosphoenolpyruvate (pep)-dependent phosphorylation of enzyme i is assumed to be associated with a high activity state of adenylate cyclase. the pyruvate or sugar-dependent dephosphorylation of enzyme i is correlated with a low a ... | 1978 | 219294 |
| etiology of pediatric gastroenteritis in rochester, minnesota. | the cause of diarrhea in a rochester, minnesota, pediatric population was studied by examining specimens for the presence of enterotoxigenic strains of escherichia coli and reovirus-like agents, in addition to parasites and other bacteria and viruses. reovirus-like agents were detected by electron microscopy in the feces of 11 of 31 patients, but none was found from specimens collected during convalescence or from 16 asymptomatic matched controls (p less than 0.01). infection due to reovirus-lik ... | 1979 | 219302 |
| preparation and properties of a met-trnaf binding factor from rat liver and rat hepatoma. | a met-trnaf binding factor (if-2) from the microsomal fraction of rat liver and rat hepatoma ascites cells was partially purified by ammonium sulphate fractionation, deae-cellulose and phosphocellulose chromatography. the factor binds [3h]met-trnaf only in the presence of either gtp or gmppcp. maximal binding takes place at 37 degrees c and in the absence of mg++. the factor is specific for met-trnaf and does not bind phe-trna from rat liver or from e. coli. the ternary complex [met-trnaf . if-2 ... | 1978 | 219643 |
| the experimental production of diarrhoea in colostrum deprived axenic and gnotoxenic calves with enteropathogenic escherichia coli, rotavirus, coronavirus and in a combined infection of rotavirus and e. coli. | we attempted to produce diarrhoea experimentally in the newborn calf by orally injecting 17 colostrum-deprived calves with two serotypes of escherichia coli ent+ k99+, a rotavirus and a coronavirus. with e. coli alone, a dose of 2 x 10(8) bacteria administered 24 hours after birth causes a mild attack of diarrhoea, whereas 1 x 10(10) bacteria leads to dehydration and death. an inoculation of rotavirus is followed by diarrhoea which always contains large quantities of rotavirus. these animals wer ... | 1978 | 219751 |
| scanning electron microscopy of abomasium and intestine of gnotoxenic calves infected either with rotavirus, coronarivus or enteropathogenic escherichia coli or with rotavirus and e. coli. | neonatal calf diarrhoea induced with several agents of infection was studied by scanning electron microscopy. in a gnotoxenic calf infected with e. coli k99+ ent+, slight lesions of the small intestine were observed and desquamation or puffiness of microvilli occurred. in rotavirus-infected calves, the abomasum was covered with abudant mucous film and appeared to be desquamated. in the small intestine, no desquamation of epithelium was observed. inoculation of the rotavirus and e. coli induced s ... | 1978 | 219752 |
| intestinal strangulation in germfree and monocontaminated dogs. | earlier studies in the germfree rat demonstrated that the common intestinal bacteria vary greatly in their ability to cause death after intestinal strangulation. some of these experiments were repeated in adult, germfree and monocontaminated beagles. neither short closed-loop hemorrhagic nor long closed-loop ischemic strangulation killed the germfree dog. either procedure rapidly killed the dog with a conventional bacterial flora or a dog monocontaminated with clostridium perfringens. the dogs m ... | 1979 | 219816 |
| the purification of nuclease-free t4-rna ligase. | rna ligase has been highly purified in good yields from bacteriophage t4-infected escherichia coli by a rapid and reproducible procedure. the enzyme is free of phosphomonoesterase and ribonuclease activities and is therefore suitable for the synthesis of oligoribonucleotides and for the labeling of the 3'-terminus of rna. greater than 90% of the protein in the enzyme preparation migrates as a single band on gradient polyacrylamide gels containing sodium dodecyl sulfate during electrophoresis. fo ... | 1979 | 219895 |
| [interrelationship between metabolic and genetic regulation of alkaline phosphatase and poly- and pyrophosphatases]. | the effects of orthophosphate and mutations in the regulatory genes of alkaline phosphatase on the activities of pyrophosphatase and polyphosphatase of e. coli were studied. it was shown that orthophosphate represses the synthesis of alkaline phosphatase as well as that of polyphosphatase without having any effect on pyrophosphatase. the genes phor and phos are involved in the formation of a repressory complex both for alkaline phosphatase and polyphosphatase. the gene phot is probably involved ... | 1979 | 219915 |
| characteristics of a low-molecular-weight factor extracted from mouse tumors that affects in vitro properties of macrophages. | a dialysable low-molecular-weight factor capable of affecting in vitro properties of macrophages was extracted from four different mouse tumors. this factor not only modulates closely related properties of peritoneal macrophages such as spreading and migration but also inhibits lipopolysaccharde-induced tumoricidal activity of these cells. it can be extracted not only from tumor tissues but also from tumor cells grown in vitro. the appearance of this factor is unique to tumors and it is not pre ... | 1979 | 220197 |
| properties of two cyclic nucleotide-deficient mutants of neurospora crassa. | studies on the crisp-1 (cr-1), cyclic adenosine 3',5'-monophosphate (camp)-deficient mutants of neurospora crassa were undertaken to characterize the response of these mutants to exogenous cyclic nucleotides and cyclic nucleotide analogs. a growth tube bioassay and a radioimmune assay for cyclic nucleotides yielded the following results. (i) 8-bromo camp and n6-monobutyryl camp but not dibutyryl camp are efficient camp analogs in neurospora, stimulating mycelial elongation of the cr-1 mutants. e ... | 1979 | 220210 |
| pyridine nucleotide cycle of salmonella typhimurium: isolation and characterization of pnca, pncb, and pncc mutants and utilization of exogenous nicotinamide adenine dinucleotide. | mutants of salmonella typhimurium lt-2 deficient in nicotinamidase activity (pnca) or nicotinic acid phosphoribosyltransferase activity (pncb) were isolated as resistant to analogs of nicotinic acid and nicotinamide. information obtained from interrupted mating experiments placed the pnca gene at 27 units and the pncb gene at 25 units on the s. typhimurium lt-2 linkage map. a major difference in the location of the pnca gene was found between the s. typhimurium and escherichia coli linkage maps. ... | 1979 | 220211 |
| catabolite and transient repression in escherichia coli do not require enzyme i of the phosphotransferase system. | transient and catabolite repression with changes in intracellular concentrations of cyclic adenosine 3',5-monophosphate is produced by glycerol and by glucose-6-phosphate in a strain with a partial deletion of the structural gene for enzyme i of the phosphoenolpyruvate:sugar phosphotransferase system. | 1979 | 220212 |
| travelers' diarrhea among u.s. army troops in south korea. | a prospective study of diarrhea was conducted among 98 u.s. army soldiers during their first six weeks in south korea. diarrhea developed in 54 (55%) of 98 soldiers and had a mean duration of five days. infections with salmonella, shigella, vibrio, enterotoxigenic escherichia coli, enteroviruses, and intestinal parasites were uncommon. four (8%) of 50 soldiers with documented diarrhea, two (6%) or 32 with a history of diarrhea, and one (3%) of 29 who denied gastrointestinal symptoms had serologi ... | 1979 | 220334 |
| transcription of in vitro assembled chromatin by escherichia coli rna polymerase. | | 1979 | 220426 |
| preparation and assay of purified escherichia coli polysomes devoid of free ribosomal subunits and endogenous gtpase activities. | | 1979 | 220498 |
| isolation and characterization of escherichia coli mutants auxotrophic for thiamine phosphates. | | 1979 | 220507 |
| etiology of infantile enteritis in south africa. | infantile enteritis constitutes a major health problem in developing countries. several investigations into the etiology of this condition among various south african populations have been undertaken during the past few years. recent studies of black urban infants have revealed that salmonellae, shigellae, enterotoxigenic enterobacteriaceae, and rotaviruses play a relatively minor role in infantile enteritis. on the other hand, all studies, including a number performed several years ago, have de ... | 1979 | 221438 |
| characterization of a high activity form of ribonucleoside diphosphate reductase from escherichia coli. | | 1979 | 221457 |