Showing papers on "Escherichia coli published in 1981"
TL;DR: A strong positive correlation between the tRNA abundance and the choice of codons, among both synonymous codons and those corresponding to different amino acids, was found for all E. coli protein genes that had been sequenced completely; the correlation was less significant for the phage genes.
903 citations
TL;DR: Both pilus types were found to be genetically distinct, and unlike the adherence genes from bovine, porcine, and human diarrheal isolates, both were finding to be chromosomally encoded.
Abstract: Isolates of Escherichia coli from human urinary tract infections frequently express adherence properties found less often among normal intestinal isolates. These properties include adherence to human uroepithelial cells and primary monkey kidney cells, as well as D-mannose-resistant hemagglutination of human erythrocytes, and they are mediated by a pilus type different from type 1. The genes encoding this pilus type (pyelonephritis-associated pili, pap) and those encoding type 1 pili have been cloned from a urinary tract infection isolate of E. coli and transferred to an E. coli K-12 derivative. The recombinant plasmids were found to express functional pili and to endow the new host with all of the adherence properties of the urinary tract infection isolate. Both pilus types were found to be genetically distinct, and unlike the adherence genes from bovine, porcine, and human diarrheal isolates, both were found to be chromosomally encoded.
568 citations
TL;DR: Evidence is presented that suggests the promoter operator of the meta pathway gene functions less effectively with the RNA polymerase or xylS product of E. coli than with the enzyme or product of P. putida.
Abstract: The genetic organization of the Pseudomonas putida plasmid pWWO-161, which encodes enzymes for the degradation of toluene and related aromatic hydrocarbons, has been investigated by transposition mutagenesis and gene cloning. Catabolic genes were localized to two clusters, one for upper pathway (hydrocarbon leads to carboxylic acid) enzymes and the other for lower pathway (carboxylic acid leads to tricarboxylic acid cycle) enzymes, that are separated by a 14-kilobase DNA segment. The physical organization of the catabolic genes thus reflects their functional organization into two regulatory blocks. The pWWO-161 DNA fragments Sst I fragment C and fragment D were cloned in a broad host range vector to produce plasmid pKT530. This hybrid encodes toluate oxygenase and all meta cleavage pathway enzymes, and it enables P. putida mt-2 and Escherichia coli K-12 cells to grow on m-toluate as sole carbon source. The pKT530 plasmid also carries xylS (a gene whose product has been postulated to regulate expression of the lower pathway genes) and the control sequences of the pathway that interact with this product, because catechol 2,3-oxygenase synthesis is specifically induced by m-toluate in both P. putida and E. coli. Evidence is presented that suggests the promoter operator of the meta pathway gene functions less effectively with the RNA polymerase or xylS product of E. coli than with the enzyme or product of P. putida.
553 citations
TL;DR: An improved medium for the direct, positive selection of tetracycline-sensitive clones from a population of t Petracy Cline-resistant strains of Escherichia coli is described.
Abstract: An improved medium for the direct, positive selection of tetracycline-sensitive clones from a population of tetracycline-resistant strains of Escherichia coli is described.
553 citations
TL;DR: A DNA sequence coding for the immunogenic capsid protein VP3 of foot-and-mouth disease virus A12 was ligated to a plasmid designed to express a chimeric protein from the Escherichia coli tryptophan promoter-operator system, which elicited high levels of neutralizing antibody and protection against challenge with foot- and- Mouth disease virus.
Abstract: A DNA sequence coding for the immunogenic capsid protein VP3 of foot-and-mouth disease virus A12, prepared from the virion RNA, was ligated to a plasmid designed to express a chimeric protein from the Escherichia coli tryptophan promoter-operator system. When Escherichia coli transformed with this plasmid was grown in tryptophan-depleted media, approximately 17 percent of the total cellular protein was found to be an insoluble and stable chimeric protein. The purified chimeric protein competed equally on a molar basis with VP3 for specific antibodies to foot-and-mouth disease virus. When inoculated into six cattle and two swine, this protein elicited high levels of neutralizing antibody and protection against challenge with foot-and-mouth disease virus.
485 citations
TL;DR: In most of the children with acute pyelonephritis the urinary pathogen was the predominant E. coli strain of the periurethral and faecal flora and the results were similar in three different studies.
450 citations
TL;DR: Sau 3A1 partial digestion fragments from Bacillus thuringiensis var. kurstaki HD-1 plasmid DNA were ligated into the BamHI site of the cloning vector pBR322 and transformed into Escherichia coli strain HB101 as mentioned in this paper.
Abstract: Sau 3A1 partial digestion fragments from Bacillus thuringiensis var. kurstaki HD-1 plasmid DNA were ligated into the BamHI site of the cloning vector pBR322 and transformed into Escherichia coli strain HB101. Colonies presumed to contain recombinant plasmids were screened for production of an antigen that would react with antibody made against B. thuringiensis crystals. One strain, ES12, was isolated by using this procedure. ES12 contains a plasmid of Mr 11 X 10(6) that has DNA sequence homology with pBR322 as well as with Mr 30 X 10(6) and Mr 47 X 10(6) plasmids of B. thuringiensis. It makes a protein antigen, detected by antibodies to crystal, which has the same electrophoretic mobility as the B. thuringiensis crystal protein. Protein extracts of ES12 are toxic to larvae of the tobacco hornworm Manduca sexta.
435 citations
01 Jan 1981
394 citations
TL;DR: The bacterial surface antigen(s) mediating mannose-resistant hemagglutination of human erythrocytes and attachment to human urinary tract epithelial cells may be one factor selecting for E. coli from among the fecal flora which infect the urinary tract.
Abstract: The capacity of 453 Escherichia coli strains to agglutinate erythrocytes and yeast cells and to attach to human urinary tract epithelial cells was tested. The strains were isolated from the urine of patients with acute pyelonephritis, acute cystitis, or asymptomatic bacteriuria and from the stools of healthy school children. Three main patterns of hemagglutination were found: (i) mannose-resistant agglutination of human erythrocytes alone or simultaneously with mannose-sensitive agglutination of guinea pig erythrocytes; (ii) only mannose-sensitive agglutination of guinea pig and other erythrocytes; and (iii) no agglutination. Strains with mannose-resistant agglutination of human erythrocytes alone or in combination with mannose-sensitive hemagglutination attached in high numbers to human urinary tract epithelial cells. Bacteria inducing only mannose-sensitive hemagglutination attached in low numbers, and non-agglutinating strains did not bind to the urinary tract epithelial cells. The bacterial surface antigen(s) mediating mannose-resistant hemagglutination of human erythrocytes and attachment to human urinary tract epithelial cells may be one factor selecting for E. coli from among the fecal flora which infect the urinary tract. The highest proportion of strains with this property was found among acute pyelonephritis isolates (77%), and the lowest proportion of strains with this property was found among normal fecal E. coli (16%).
347 citations
TL;DR: Alterations in the ATP-dependent protease in the lon- mutants can account for the defect in intracellular proteolysis and perhaps also for the other phenotypic effects of this pleiotropic gene.
Abstract: In Escherichia coli, degradation of abnormal proteins is an energy-requiring process; it is decreased in mutants in the lon (capR or deg) gene. We find that the protein encoded by the lon gene is an ATP-dependent protease and is identical to protease La, recently described in E. coli. Both proteins are serine proteases that hydrolyze casein and globin, but not insulin, in the presence of ATP and Mg2+. Both respond to ATP, less well to other nucleoside triphosphates, and not to nonhydrolyzable ATP analogs. The purified lon protein has an apparent Mr of 450,000 and appears to be composed of four identical subunits. Its size, chromatographic behavior, and sensitivity to various inhibitors and heat are indistinguishable from those of protease La. Moreover, in a strain that carries additional copies of the lon+ allele on a plasmid, the content of protease La, but not of other proteases, is 2- to 10-fold greater than in the lon+ parent strain. Strains carrying the nonsense mutations capR9 and capR- also contain this ATP-dependent proteolytic activity, but it is present in substantially lower amounts and is inactivated by phosphocellulose chromatography, unlike the wild-type enzyme. Degradation of abnormal proteins in these lon- strains, which is slower than in the wild type, still requires ATP. Alterations in the ATP-dependent protease in the lon- mutants can account for the defect in intracellular proteolysis and perhaps also for the other phenotypic effects of this pleiotropic gene.
339 citations
TL;DR: The complete nucleotide sequence for the five structural genes of the trp operon of E. coli together with the internal and flanking regions of regulatory information are presented.
Abstract: The tryptophan (trp) operon of Escherichia coli has become the basic reference structure for studies on tryptophan metabolism. Within the past five years the application of recombinant DNA and sequencing methodologies has permitted the characterization of the structural and functional elements in this gene cluster at the molecular level. In this summary report we present the complete nucleotide sequence for the five structural genes of the trp operon of E. coli together with the internal and flanking regions of regulatory information.
TL;DR: It is reported that an isolated DNA sequence encoding haemolysin, added by recombinant DNA technology to avirulent non-haemolytic faecal isolates of E. coli, results in strains having enhanced virulence as measured in an experimental rat peritonitis model.
Abstract: Escherichia coli is the predominant facultative microorganism isolated from the gastrointestinal tract of man and is the most common enteric organism causing extra-intestinal infections in man, particularly of the urinary tract, peritoneum and blood1,2. It is likely that a consortium of virulence factors is responsible for the initiation and severity of extra-intestinal E. coli infections. Properties reported to be associated with the virulence of such infections include haemolysin production3, K1 antigen production4,5, various O antigens5 and Fe sequestration6. For example, it has long been recognized that the ability to lyse erythrocytes is a phenotype more common to E. coli strains isolated from infections than those found in normal faeces3,7–9. It is not clear whether the haemolysin per se is a virulence determinant. However, here we report that an isolated DNA sequence encoding haemolysin, added by recombinant DNA technology to avirulent non-haemolytic faecal isolates of E. coli, results in strains having enhanced virulence as measured in an experimental rat peritonitis model.
TL;DR: The association of MRHA and P specificity with upper urinary tract infection in children is greater than that of any other laboratory-defined bacterial characteristic.
TL;DR: The glycolipid composition of the urogenital epithelium and kidney tissue and the ability of uropathogenic E. coli to bind to these Glycolipids may be a determinant in host-parasite interaction leading to urinary tract infection.
Abstract: A specific family of glycolipids, the globoseries, was shown to act as receptors on human uroepithelial cells and erythrocytes for the majority of uropathogenic Escherichia coli strains attaching to or hemagglutinating those cells. This was demonstrated in three different ways: (i) correlation between the natural presence of glycolipid in the target cell (erythrocytes of different species) and binding of bacteria; (ii) inhibition of attachment to human uroepithelial cells by preincubation of bacteria and glycolipid; and (iii) induction of binding to unreactive cells by coating of these cells with glycolipid. Strains reacting with the receptor agglutinated guinea pig erythrocytes in a mannose-resistant way after, but not before, coating of the cells with globotetraosylceramide. Unrelated glycolipids were not recognized. The reaction was made independent of simultaneous occurrence of mannose-sensitive adhesions on the strains by addition of D-mannose. The receptor-coated cells were used as a tool to screen for prevalence of receptor recognition in a collection of 453 E. coli strains isolated from patients with urinary tract infection or from the stools of healthy children. Of 150 strains attaching to human uroepithelial cells and agglutinating human erythrocytes, 121 bound to globotetraosylceramide (81%). Globoside recognition was especially frequent among pyelonephritis strains (74/81). The glycolipid composition of the urogenital epithelium and kidney tissue and the ability of uropathogenic E. coli to bind to these glycolipids may be a determinant in host-parasite interaction leading to urinary tract infection.
TL;DR: The recA protein of Escherichia coli promotes the complete exchange of strands between full-length linear duplex and single-stranded circular DNA molecules of bacteriophage phi X-174, converting more than 50% of the single-Stranded DNA into heteroduplex replicative form II-like structures.
Abstract: The recA protein of Escherichia coli promotes the complete exchange of strands between full-length linear duplex and single-stranded circular DNA molecules of bacteriophage phi X-174, converting more than 50% of the single-stranded DNA into heteroduplex replicative form II-like structures. Kinetically, the reaction can be divided into two phases, formation of short heteroduplex regions (D loops) and extension of the D loops via branch migration. recA protein participates directly in both phases. D loops are formed efficiently in the presence of ATP or the nonhydrolyzable ATP analog adenosine 5'-[gamma-thio]triphosphate, whereas D-loop extension requires continuous ATP hydrolysis. Complete strand exchange requires a stoichiometric amount of recA protein and is strongly stimulated by the single-stranded-DNA-binding protein of E. coli.
TL;DR: Fine-structure mapping and complementation analysis of the ompB locus indicate that this locus is comprised of two genes, envZ and ompR, which according to this model are a bifunctional regulatory protein and an envelope protein that senses the cell's external environment.
TL;DR: An operon fusion of the lac genes to those required for synthesis of type 1 fimbriae (pili) has been achieved in a K12 strain of Escherichia coli lysogenized by the bacteriophage mu d (Ap4, lac), demonstrating that phase variation between fimbRIate and nonfimbriate states is under transcriptional control.
Abstract: An operon fusion of the lac genes to those required for synthesis of type 1 fimbriae (pili) has been achieved in a K12 strain of Escherichia coli lysogenized by the bacteriophage mu d (Ap4, lac). Synthesis of beta-galactosidase, therefore, reflected pil gene transcription and was used as a probe of fimbrial regulation. Expression of the operon fusion was found to oscillate, demonstrating that phase variation between fimbriate and nonfimbriate states is under transcriptional control. The transition rates from fimbriate to nonfimbriate were 1.05 X 10(-3) per bacterium per generation and from nonfimbriate to fimbriate, 3.12 X 10(-3) per bacterium per generation.
TL;DR: Genetic analysis of the regulation of beta-galactosidase in UmuC::Mud(Ap, lac) strains suggests that the lexA protein is the direct repressor of the umuC gene and that a function of the recA protein, probably its protease activity, is required for the removal of the LexA repressor at the time ofUmuC induction.
Abstract: The product of the umuC gene is required for UV and chemical mutagenesis in Escherichia coli. By the use of the Mud(Ap, lac) bacteriophage, we have obtained an operon fusion of the lac structural genes to the promoter/regulatory region of the umuC gene. The strain containing the umuC::Mud(Ap, lac) fusion was identified on the basis of its UV nonmutability. Strains containing this putative null allele of umuC were (i) nonmutable by UV and other agents, (ii) slightly UV sensitive, and (iii) deficient in their ability to carry out Weigle reactivation of UV-irradiation bacteriophage lambda. The UV nonmutability of the strain could be suppressed by a derivative of the mutagenesis-enhancing plasmid pKM101. beta-Galactosidase synthesis in umuC::Mud(Ap, lac) fusion strains was inducible by UV and other DNA-damaging agents. Genetic analysis of the regulation of beta-galactosidase in umuC::Mud(Ap, lac) strains suggests that the lexA protein is the direct repressor of the umuC gene and that a function of the recA protein, probably its protease activity, is required for the removal of the lexA repressor at the time of umuC induction.
TL;DR: Based on the studies of the E. coli top mutants, it appears that the supX gene, which was originally studied in Salmonella typhimurium, is likely to be the structural gene for DNA topoisomerase I, which has a more rapid rate of induction and a higher level of catabolite-sensitive enzymes including tryptophanase and beta-galactosidase.
Abstract: Mutations in top, the structural gene for Escherichia coli DNA topoisomerase I, have been identified and mapped at 28 min on the chromosome, near cysB. Strains carrying deletions of the top gene are viable. The top mutations, however, do exert pleiotropic effects on transcription and transposition. Mutants lacking DNA topoisomerase I have a more rapid rate of induction and a higher level of catabolite-sensitive enzymes including tryptophanase and beta-galactosidase. This general activation of transcription by top mutations can be attributed to an increase in the negative superhelicity of the DNA in vivo when the topoisomerase activity is abolished. The frequency of transposition of Tn5, a transposon carrying kanamycin resistance, is decreased by a factor of 40 or more in top mutants. A direct or indirect role of the topoisomerase in transposition is discussed. The transposition frequency of Tn3, however, is not dependent on top. Based on the studies of the E. coli top mutants, it appears that the supX gene, which was originally studied in Salmonella typhimurium [Dubnau, E. & Margolin, P. (1972) Mol. Gen. Genet. 117, 91-112] is likely to be the structural gene for DNA topoisomerase I.
TL;DR: The recA protein of Escherichia coli binds both single- (SS) and double-stranded (DS) DNA; however, the optimal conditions differ for interaction with these DNA substrates.
TL;DR: It is shown that despite its activity in repressor cleavage, ATP gamma S is hydrolyzed at a negligible rate by the recA protein DNA-dependent nucleoside triphosphatase activity.
TL;DR: Two insertion elements, IS1 and IS5, have been observed to effect activation of the cryptic bgl operon of Escherichia coli K12 and the operon is inducible by βglucosides in a cyclic AMP-dependent manner.
Abstract: Spontaneous mutations which activate the cryptic bgl operon of Escherichia coli K12 are caused by insertion of DNA at a site, bglR, within the operon. Two insertion elements, IS1 and IS5, have been observed to effect this activation. Once the activating insertion has occurred the operon is inducible by βglucosides in a cyclic AMP-dependent manner.
TL;DR: A purified preparation of the Escherichia coli integration host factor displays two polypeptides of apparent molecular weight 11,000 and 9,500 when analyzed by polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate.
TL;DR: A group of nine proteins of Escherichia coli K12 vary in steady state level with growth temperature, and are particularly abundant above 40°C, and evidence suggests that this regulatory gene, htpR, makes an activator protein that is required for heat induction of HTP proteins.
TL;DR: With this procedure, gram quantities of recA protein, greater than 99% pure, can be reproducibility prepared for biochemical and biophysical analysis.
TL;DR: Results indicate that the peptidoglycan-synthetic enzyme activities of penicillin-binding protein 3 may be involved in the process of cell division.
TL;DR: A membrane filter procedure for enumerating Escherichia coli was developed and evaluated, and the recovery of E. coli from marine, estuarine, and freshwater samples exceeded 90%.
Abstract: A membrane filter procedure for enumerating Escherichia coli was developed and evaluated. The method quantifies E. coli within 24 h without requiring subculture and identification of isolates. It incorporates a primary selective-differential medium for gram-negative, lactose-fermenting bacteria; resuscitation of weakened organisms by incubation for 2 h at 35 degrees C before incubation at 44.5 degrees C for 18 to 22 h; and an in situ urease test to differentiate E. coli from other thermotolerant, lactose-positive organisms. The recovery of E. coli from marine, estuarine, and freshwater samples exceeded 90%. Of the presumptively positive colonies, 91% were verified as E. coli. Less than 1% of all of the verified E. coli colonies failed to react typically.
TL;DR: Reconstruction experiments involving a chelator-deficient mutant growing with exogenous chelator suggested that association of a small fraction of the total siderophore synthesized with cellular material is due to transient binding of aerobactin to membrane receptors during active bacterial growth.
Abstract: Certain strains of Escherichia coli associated with bacteremia of humans and domestic animals harbor plasmids that promote efficient iron uptake. The mechanism, which is an important component of the virulence of invasive strains, is independent of the enterobactin system for iron uptake. Plasmid-specified siderophore was assayed by its ability to support the growth of a chelator-deficient mutant in conditions of iron deprivation. The chelator, which was chemically determined to be a hydroxamate compound, was identical on the basis of field desorption mass spectrometry with aerobactin, a siderophore synthesized by Aerobacter aerogenes. In conditions of iron stress, aerobactin is secreted into the culture medium of plasmid-bearing E. coli strains. Reconstruction experiments involving a chelator-deficient mutant growing with exogenous chelator suggested that association of a small fraction of the total siderophore synthesized with cellular material is due to transient binding of aerobactin to membrane receptors during active bacterial growth.
TL;DR: Carbenicillin-resistant mutants of Escherichia coli K-12 and B/r were found to produce greatly diminished levels of the porin coded by the ompF gene.
Abstract: Carbenicillin-resistant mutants of Escherichia coli K-12 and B/r were found to produce greatly diminished levels of the porin coded by the ompF gene. Physiological and ecological implications of these findings are discussed.