Publications
| Title | Abstract | Year Filter | PMID(sorted descending) Filter |
|---|
| coupling efficacy and selectivity of the human mu-opioid receptor expressed as receptor-galpha fusion proteins in escherichia coli. | two constructs encoding the human micro-opioid receptor (hmor) fused at its c terminus to either one of two galpha subunits, galpha(o1) (hmor-galpha(o1)) and galpha(i2) (hmor-galpha(i2)), were expressed in escherichia coli at levels suitable for pharmacological studies (0.4-0.5 pmol/mg). receptors fused to galpha(o1) or to galpha(i2) maintained high-affinity binding of the antagonist diprenorphine. affinities of the micro-selective agonists morphine, [d-ala(2),n-me-phe(4),gly(5)-ol]enkephalin (d ... | 2000 | 10936202 |
| isolation of shiga toxin-producing escherichia coli including o157:h7 strains from dairy cattle and beef samples marketed in calcutta, india. | 2000 | 10933264 | |
| p64k meningococcal protein as immunological carrier for weak immunogens. | previously, the p64k meningococcal protein, an antigen of 64 kda expressed in escherichia coli, has been extensively characterized. we have successfully conjugated several synthetic peptides and meningococcal group c polysaccharide to p64k. in three out of four model peptides, the murine humoral immune response against the homologous peptide, evaluated after three doses of conjugate, was higher in the animals immunized with the coupled peptide than in those that received free peptide. the fourth ... | 2000 | 10931377 |
| inhibition of six serine proteinases of the human coagulation system by mutants of bovine pancreatic trypsin inhibitor. | a series of 12 bovine pancreatic trypsin inhibitor variants mutated in the p(4) and p(3) positions of the canonical binding loop containing additional k15r and m52l mutations were used to probe the role of single amino acid substitutions on binding to bovine trypsin and to the following human proteinases involved in blood clotting: plasmin, plasma kallikrein, factors x(a) and xii(a), thrombin, and protein c. the mutants were expressed in escherichia coli as fusion proteins with the le1413 hydrop ... | 2000 | 10930417 |
| chalcone and stilbene synthases expressed in eucaryotes exhibit reduced cross-reactivity in vitro. | chalcone synthase (chs) and stilbene synthase (sts) catalyze different cyclization reactions of the common tetraketide to give different products, naringenin chalcone and resveratrol, respectively. we have previously observed in vitro cross-reaction of chs and sts overexpressed in escherichia coli, resveratrol production by chs and chalcone production by sts. when expressed in eucaryotic cells, or in e. coli as thioredoxin-fusion proteins, chs and sts exhibited reduced cross-reaction. sts refold ... | 2000 | 10923839 |
| rotational mobility and orientational stability of a transport protein in lipid membranes. | a single-cysteine mutant of the lactose transport protein lacs(c320a/w399c) from streptococcus thermophilus was selectively labeled with a nitroxide spin label, and its mobility in lipid membranes was studied as a function of its concentration in the membrane by saturation-transfer electron spin resonance. bovine rhodopsin was also selectively spin-labeled and studied to aid the interpretation of the measurements. observations of spin-labeled proteins in macroscopically aligned bilayers indicate ... | 2000 | 10920009 |
| antiviral activity of shiga toxin 1: suppression of bovine leukemia virus-related spontaneous lymphocyte proliferation. | human infections with shiga toxin (stx)-producing escherichia coli (stec) cause hemorrhagic colitis. the stxs belong to a large family of ribosome-inactivating proteins (rips) that are found in a variety of higher plants and some bacteria. many rips have potent antiviral activity for the plants that synthesize them. stec strains, both virulent and nonvirulent to humans, are frequently isolated from healthy cattle. interestingly, despite intensive investigations, it is not known why cattle carry ... | 2000 | 10899843 |
| influence of hmg-1 and adenovirus oncoprotein e1a on early stages of transcriptional preinitiation complex assembly. | the tata-binding protein (tbp) in the tfiid complex binds specifically to the tata-box to initiate the stepwise assembly of the preinitiation complex (pic) for rna polymerase ii transcription. transcriptional activators and repressors compete with general transcription factors at each step to influence the course of the assembly. to investigate this process, the tbp.tata complex was titrated with hmg-1 and the interaction monitored by electrophoretic mobility shift assays. the titration produced ... | 2000 | 10882737 |
| antigenic and genetic characterization of lipoprotein lppq from mycoplasma mycoides subsp. mycoides sc. | lipoprotein lppq, a predominant 48-kda antigen, and its corresponding gene, lppq, were characterized in mycoplasma mycoides subsp. mycoides sc, the etiological agent of contagious bovine pleuropneumonia. the lppq gene is specific to m. mycoides subsp. mycoides sc and was found in the type strain and in field strains isolated in europe, africa, and australia, as well as in vaccinal strains. lppq is encoded as a precursor with a consensus sequence for prokaryotic signal peptidase ii and a lipid at ... | 2000 | 10882657 |
| survival of verocytotoxigenic escherichia coli o157 in soil, water and on surfaces. | cattle and sheep are major reservoirs of escherichia coli o157 and consequently these and certain other farm animals can pass out large numbers of this organism in their faeces. thus the ability of the organism to survive in faeces, on pastureland and in associated water systems has important implications for its spread to crops by direct application of manure, by irrigation with infected water or directly to man by contact with animals or contaminated soil. model systems were used to determine ... | 2000 | 10880181 |
| role of non-o157 vtec. | non-o157 vtec are typical escherichia coli that differ only in their ability to produce verocytotoxins (vt). the transmission of vtec is discussed in relation to the transmission of commensal e. coli. the emergence over the last few decades of a great variety of vtec serotypes from healthy and diseased humans and animals is described. particular attention is given to the distribution of the more important serogroups pathogenic for humans that have been described from around the world, particular ... | 2000 | 10880178 |
| the genetic diversity of predominant escherichia coli strains isolated from cattle fed various amounts of hay and grain(1). | when the 16s rdna of predominant escherichia coli strains from cattle was digested with hhai and haeiii, the strains could be sub-divided into four operational taxonomic units. when genomic dna was digested with xbai, strains could be grouped into 24 pulsed-field gel electrophoresis genotypes (>95% dice similarity) and five clades (>20% dice similarity). diet (hay versus grain) and gastrointestinal compartment (rumen versus colon) did not have a large impact on diversity. however, both analyses ... | 2000 | 10858581 |
| molecular cloning and expression of cu/zn-containing superoxide dismutase from fasciola hepatica. | the cytosolic superoxide dismutase (sod) of fasciola hepatica, a causative agent of fascioliasis, was purified and characterized. the enzyme consists of two identical subunits, each with an apparent molecular mass of 17.5 kda. an analysis of the enzyme's primary structure and inhibition studies revealed that the enzyme is a copper/zinc-containing sod (cu/zn-sod). the enzyme activity was relatively stable in a broad ph range, from ph 7.0 to 10.0, and the enzyme showed maximum activity at ph 7.5. ... | 2000 | 10858207 |
| high levels of background flora inhibits growth of escherichia coli o157:h7 in ground beef. | the influence of natural background flora under aerobic and anaerobic incubation on the growth of escherichia coli o157:h7 in ground beef was investigated. the background flora from eight different commercial ground beef were added to ground beef spiked with e. coli o157:h7 and stored either aerobically or anaerobically at 12 degrees c. the results showed that the presence of a large number of background bacteria in the ground meat inhibited the growth of e. coli o157:h7 both aerobically and ana ... | 2000 | 10857548 |
| rotavirus and concurrent infections with other enteropathogens in neonatal diarrheic dairy calves in spain. | faeces samples from 218, one to 30 days old, diarrheic dairy calves in 65 dairy herds were screened for the presence of rotavirus and concurrent infections with coronavirus, cryptosporidium, f5+ escherichia coli and salmonella spp. calves were grouped according to their age as follows: 1-7, 8-14, 15-21 and 22-30 days. rotavirus infection was detected in 46.9%, 45.6%, 33.8% and 48.3% of the calves in the respective age-groups. no significant differences in the detection rate of rotavirus were fou ... | 2000 | 10855663 |
| expression of yeast inm1 encoding inositol monophosphatase is regulated by inositol, carbon source and growth stage and is decreased by lithium and valproate. | inositol monophosphatase plays a vital role in the de novo biosynthesis of inositol and in the phosphoinositide second messenger signalling pathway. we cloned the saccharomyces cerevisiae open reading frame (orf) yhr046c (termed inm1), which encodes inositol monophosphatase, characterized the protein inm1p and analysed expression of the inm1 gene. inm1 was expressed in bacteria under the control of the lacz promoter. the purified protein has inositol monophosphatase activity that is inhibited by ... | 2000 | 10844654 |
| induction of parturition with prostaglandin f2 alpha as a possible model to study impaired reproductive performance in the dairy cow. | parturitions were induced in five cows, 2 weeks before term using prostaglandin (pg) f(2alpha). two i.m. injections were performed with an interval of 24 h. all cows calved within 5 days (average 2.7 days) after the first injection of pgf(2alpha). out of five cows, four had retained fetal membranes (rfm). each animal was sampled for bacteriological examination using uterine biopsies twice a week during 42 days postpartum (pp). jugular vein blood samples were withdrawn for pgf(2alpha)-metabolite ... | 2000 | 10837974 |
| molten globule structure of equine beta-lactoglobulin probed by hydrogen exchange. | the molten globule structure of equine beta-lactoglobulin has been inferred from the hydrogen exchange protection of the backbone amide protons. in order to make it possible to measure the hydrogen exchange kinetics of the individual backbone amide protons, the uniformly (15)n-labeled recombinant protein was expressed in escherichia coli and the nmr peak assignment was obtained for most of the backbone protons. the chemical shift and noe results obtained under the condition where the protein ass ... | 2000 | 10835282 |
| resonance raman studies of oxo intermediates in the reaction of pulsed cytochrome bo with hydrogen peroxide. | cytochrome bo from escherichia coli, a member of the heme-copper terminal oxidase superfamily, physiologically catalyzes reduction of o(2) by quinols and simultaneously translocates protons across the cytoplasmic membrane. the reaction of its ferric pulsed form with hydrogen peroxide was investigated with steady-state resonance raman spectroscopy using a homemade microcirculating system. three oxygen-isotope-sensitive raman bands were observed at 805/x, 783/753, and (767)/730 cm(-)(1) for interm ... | 2000 | 10828985 |
| antimicrobial effect of herb extracts against escherichia coli o157:h7, listeria monocytogenes, and salmonella typhimurium associated with beef. | the effects of plant extracts against pathogenic bacteria in vitro are well known, yet few studies have addressed the effects of these compounds against pathogens associated with muscle foods. a series of experiments was conducted to determine the effectiveness of a commercially available, generally recognized as safe, herb extract dispersed in sodium citrate (protecta one) or sodium chloride (protecta two) against escherichia coli o157:h7, salmonella typhimurium, and listeria monocytogenes asso ... | 2000 | 10826716 |
| replacement of histidine 340 with alanine inactivates the group a streptococcus extracellular cysteine protease virulence factor. | streptococcus pyogenes expresses a highly conserved extracellular cysteine protease that is a virulence factor for invasive disease, including soft tissue infection. site-directed mutagenesis was used to generate a his340ala recombinant mutant protein that was made as a stable 40-kda zymogen by escherichia coli. purified his340ala protein was proteolytically inactive when bovine casein and human fibronectin were used as substrates. wild-type 28-kda streptococcal protease purified from s. pyogene ... | 2000 | 10816533 |
| brucella abortus strain rb51 as a vector for heterologous protein expression and induction of specific th1 type immune responses. | brucella abortus strain rb51 is a stable, rough, attenuated mutant widely used as a live vaccine for bovine brucellosis. our ultimate goal is to develop strain rb51 as a preferential vector for the delivery of protective antigens of other intracellular pathogens to which the induction of a strong th1 type of immune response is needed for effective protection. as a first step in that direction, we studied the expression of a foreign reporter protein, beta-galactosidase of escherichia coli, and th ... | 2000 | 10816476 |
| a one year study of escherichia coli o157 in raw beef and lamb products. | between april 1996 and march 1997 we examined 5093 samples of raw beef and lamb products for the presence of e. coli o157. samples were purchased from 81 small butchers' shops in south yorkshire. in march 1997 we also examined five samples of dried mint for the presence of e. coli o157. strains of e. coli o157 were isolated by enrichment culture in modified buffered peptone water followed by immunomagnetic separation and culture of magnetic beads onto cefixime tellurite sorbitol macconkey agar. ... | 2000 | 10813144 |
| isolation, characterization and expression of a gra2 homologue from neospora caninum. | a cdna library derived from mrna of tachyzoites of neospora caninum (nc-liverpool strain) was screened with antisera from a cow naturally infected with n. caninum. the dna sequence of 1 recombinant isolated predicted a significant protein sequence homology of the gene product to the 28 kda (gra2) antigen of toxoplasma gondii. studies on the n. caninum gene coding for this antigen demonstrated the presence of a single intron flanked by 2 exons; the gene was also highly expressed in culture-derive ... | 2000 | 10811279 |
| some emerging food and water borne pathogens. | emerging pathogens are those infective organisms whose incidence has recently increased or is likely to increase during the next two decades due to changes in demography, food habits, food technology, commerce, water sources and environmental factors. some important emerging food and water borne bacterial pathogens include listeria monocytogenes, campylobacter jejuni, yersinia enterocolitica, salmonella enteritidis, escherichia coli o157: h7, vibrio cholerae biotype e1 tor serotype 0139, vibrio ... | 1999 | 10810592 |
| isolation of repeated and self-complementary sequences from e. coli dna. | we have used the single-strand specific nuclease from neurospora crassa and chromatography on methylated albumin-kieselguhr to purify and characterize repeated and self-complementary sequences from escherichia coli dna. approximately 0.5% of the genome renatures spontaneously at zero time and another 2% renatures somewhat more rapidly than the total dna. the early renaturing dna has a base composition and a tm similar to the total dna and contains on the average 100 base pairs; the self-compleme ... | 1974 | 10793709 |
| use of 8-hydroxyquinoline-beta-d-glucuronide for presumptive identification of shiga toxin-producing escherichia coli o157. | 8-hydroxyquinoline-beta-d-glucuronide (hqg) was used to improve the presumptive identification of shiga toxin-producing escherichia coli o157 (stec o157) on sorbitol macconkey agars (smac). advantages of hqg are (i) that it is less expensive than 5-bromo-4-chloro-3-indoxyl-glucuronide; (ii) that it is visible in normal daylight and (iii) that it does not diffuse into the agar like 4-methylumbelliferryl-beta-d-glucuronide (mug). sixteen stec o157 isolates, 91 bovine mastitis-associated e. coli is ... | 2000 | 10792673 |
| invited review: effects of diet shifts on escherichia coli in cattle. | escherichia coli o157:h7 is a pathogenic bacterium that causes acute illness in humans, but mature cattle are not affected. e. coli o157:h7 can enter the human food supply from cattle via fecal contamination of beef carcasses at slaughter. previous attempts to correlate the incidence of e. coli o157:h7 with specific diets or feeding management practices gave few statistically significant or consistent findings. however, recent work indicates that cattle diets may be changed to decrease fermentat ... | 2000 | 10791804 |
| specificity determinants for the pyruvate dehydrogenase component reaction mapped with mutated and prosthetic group modified lipoyl domains. | efficient catalysis in the second step of the pyruvate dehydrogenase (e1) component reaction requires a lipoyl group to be attached to a lipoyl domain that displays appropriately positioned specificity residues. as substrates, the human dihydrolipoyl acetyltransferase provides an n-terminal (l1) and an inner (l2) lipoyl domain. we evaluated the specificity requirements for the e1 reaction with 27 mutant l2 (including four substitutions for the lipoylated lysine, lys(173)), with three analogs sub ... | 2000 | 10788482 |
| enzyme-mediated sulfide production for the reconstitution of [2fe-2s] clusters into apo-biotin synthase of escherichia coli. sulfide transfer from cysteine to biotin. | we previously showed that biotin synthase in which the (fe-s) cluster was labelled with 34s by reconstitution donates 34s to biotin [b. tse sum bui, d. florentin, f. fournier, o. ploux, a. méjean & a. marquet (1998) febs lett. 440, 226-230]. we therefore proposed that the source of sulfur was very likely the (fe-s) centre. this depletion of sulfur from the cluster during enzymatic reaction could explain the absence of turnover of the enzyme which means that to restore a catalytic activity, the c ... | 2000 | 10785391 |
| identification of the f17 fimbrial subunit- and adhesin-encoding (f17a and f17g) gene variants in necrotoxigenic escherichia coli from cattle, pigs and humans. | putative colonization factors of the f17 family of fimbrial adhesins have been identified in necrotoxigenic escherichia coli type 1 and type 2 (ntec1 and ntec2) from calves, pigs, and humans. the f17a and f17g gene variants, coding respectively for the major subunit and for the adhesin of the f17 fimbriae, were typed in 70 e. coli carrying f17-related sequences (15 ntec1, 51 ntec2, and four non-ntec) by colony hybridisation with gene probes derived from the different f17a gene variants (a, b, c, ... | 2000 | 10781731 |
| purification, cloning, expression, and mechanism of action of a novel platelet aggregation inhibitor from the salivary gland of the blood-sucking bug, rhodnius prolixus. | rhodnius prolixus aggregation inhibitor 1 (rpai-1), a 19-kda protein isolated from the salivary gland of r. prolixus, was purified by strong cation exchange and reverse-phase high performance liquid chromatographies. based on 49 amino-terminal amino acid sequences of rpai-1, primers were produced to generate probes to screen an r. prolixus salivary gland cdna library. a phage containing the full-length clone of rpai-1 codes for a mature protein of 155 amino acids. rpai-1 shows sequence homology ... | 2000 | 10777556 |
| rapid and specific enzyme immunoassay on hydrophobic grid membrane filter for detection and enumeration of thermophilic campylobacter spp. from milk and chicken rinses. | six commercially available anti-campylobacter antibodies were examined for their applicability in an enzyme immunoassay on hydrophobic grid membrane filters, both for the detection and enumeration of campylobacter spp. when a panel of nine campylobacter (seven campylobacter jejuni and two campylobacter coli) and eight non-campylobacter strains were used in a dot-blot format enzyme immunoassay to test the specificity of these antibodies, only one polyclonal antibody (biodesign) detected all campy ... | 2000 | 10772214 |
| formation and characterization of a single trp-trp cross-link in indolicidin that confers protease stability without altering antimicrobial activity. | indolicidin is a 13-residue cationic, antimicrobial peptide-amide isolated from the cytoplasmic granules of bovine neutrophils. the unique composition of indolicidin distinguishes it from alpha-helical and beta-structured cationic peptides, because five of indolicidin's 13 residues are tryptophans: h-ile-leu-pro-trp-lys-trp-pro-trp-trp-pro-trp-arg-arg-nh(2). solid phase synthesis of indolicidin gave rise to a minor byproduct that possessed unusual fluorescence and uv absorbance properties compar ... | 2000 | 10766833 |
| phosphoaminoglycosides inhibit swi2/snf2 family dna-dependent molecular motor domains. | members of the swi2/snf2 family of proteins participate in an array of nucleic acid metabolic functions, including chromatin remodeling and transcription. the present studies identify a novel strategy to specifically inhibit the functional dna-dependent adenosinetriphosphatase (atpase) motor domain common to swi2/snf2 family members. we have identified preparations of phosphoaminoglycosides, which are natural products of aminoglycoside-resistant bacteria, as inhibitors of the in vitro activities ... | 2000 | 10757984 |
| a quantitative approach to classifying holstein cows based on antibody responsiveness and its relationship to peripartum mastitis occurrence. | a quantitative approach was developed to classify holstein cows and heifers based on phenotypic variation of serum antibody response and to determine associations with peripartum mastitis. using an index, 136 cows and heifers were classified into high (group 1), average (group 2), or low (group 3) antibody groups following immunization with ovalbumin at wk -8, -3, and 0 relative to parturition. the ranking of groups based on the quantitative index of serum antibody response to ovalbumin were sim ... | 2000 | 10750107 |
| activity of hydrolysed lactoferrin against foodborne pathogenic bacteria in growth media: the effect of edta. | lactoferrin was hydrolysed with pepsin and the antimicrobial activity of the resulting hydrolysate (hlf) was studied in 1% peptone, 0.05% yeast extract, 1% glucose (pyg) medium and tryptic soy broth (tsb). hlf was effective against listeria monocytogenes, enterohaemorrhagic escherichia coli and salmonella enteritidis in pyg, however, the highest studied concentration (1.6 mg ml-1) did not inhibit growth of any of these organisms in tsb. the addition of edta enhanced the activity of hlf in tsb, i ... | 2000 | 10747257 |
| epidemiological study of pap genes among diarrheagenic or septicemic escherichia coli strains producing cs31a and f17 adhesins and characterization of pap(31a) fimbriae. | the association of the pap operon with the cs31a and f17 adhesins was studied with 255 escherichia coli strains isolated from calves, lambs, or humans with diarrhea. the three classes of papg adhesin with different receptor binding preferences were also screened. the pap operon was associated with 50 and 36% of human strains that produced cs31a and ovine strains that produced f17, respectively. among the bovine isolates, the pap operon was detected in 61% of the cs31a-positive isolates and 72% o ... | 2000 | 10747134 |
| inhibitory effects of bovine lactoferrin on the adherence of enterotoxigenic escherichia coli to host cells. | adherence is an essential and prerequisite step for the colonization of mucosal surfaces by enterotoxigenic escherichia coli (etec). we studied the effect of bovine lactoferrin (blf) on the adherence of etec to human epithelial cells in vitro, and to intestinal mucosa of icr germfree mice in vivo. in the in vitro study, blf was found to inhibit the adherence of etec. this adhesion-inhibiting activity of blf was found to lessen with decreasing blf concentration, but the data obtained suggest a po ... | 2000 | 10737192 |
| escherichia coli o26 detection from foods using an enrichment procedure and an immunomagnetic separation method. | we found effective enrichment procedures for detecting escherichia coli o26 in foods using methods that are used for e. coli o157. ground beef or radish sprouts inoculated with approximately 6 colony-forming units of e. coli o26 were homogenized in 225 ml of various broths. after static incubation at 37 degrees c or 42 degrees c for 6 h or 18 h, we isolated the inoculated bacterium by plating onto rainbow agar o157 with novobiocin. in combination with the immunomagnetic separation method, e. col ... | 2000 | 10736019 |
| the effects of preslaughter washing on the reduction of escherichia coli o157:h7 transfer from cattle hides to carcasses during slaughter. | fresh bovine faeces were inoculated with a non-toxigenic, antibiotic resistant strain of escherichia coli o157:h7, spread on the rump areas of 30 heifers and allowed to dry for 24 h. ten of the cattle then entered the normal slaughter process without further treatment. the remaining cattle were washed with a powerhose for 1 min (10 animals) and 3 min (10 animals) before entering the normal slaughter process. both washing treatments removed all visible faecal materials on the live animals althoug ... | 2000 | 10736017 |
| high-throughput assay for inorganic pyrophosphatases using the cytosolic enzymes of saccharomyces cerevisiae and human as an example. | this paper describes the development of a new, malachite green based, enzymatic assay for the identification of specific inhibitors of inorganic pyrophosphatase (ippase) from saccharomyces cerevisiae for antifungal drug discovery. the human ippase was used as counterscreen. the coding regions of both enzymes were amplified, cloned into a vector providing a his-tag at the c-terminus, expressed in escherichia coli, and purified by metal chelate affinity chromatography. since the complete human seq ... | 2000 | 10733883 |
| biosynthesis of heparin/heparan sulphate: mechanism of epimerization of glucuronyl c-5. | in the biosynthesis of heparin and heparan sulphate, d-glucuronic acid residues are converted into l-iduronic acid (idoa) units by c-5 epimerization, at the polymer level. the reaction catalysed by the epimerase occurs by reversible abstraction and readdition of a proton at c-5 of target hexuronic acid residues, through a carbanion intermediate, with or without an inversion of configuration at c-5 [prihar, campbell, feingold, jacobsson, jensen, lindahl and rodén (1980) biochemistry 19, 495-500]. ... | 2000 | 10727403 |
| effects of sodium fertilizers and supplements on milk production and mammary gland health. | a series of experiments was conducted to investigate the effects of sodium fertilizers and supplements on the milk production and mammary health of dairy cows. in expt 1, where sodium fertilizer was applied to productive pastures consisting mainly of the natrophile perennial rye-grass, the herbage sodium content and the milk yield of cows was increased and milk somatic cell count (scc) reduced. in expt 2, which used pastures containing less productive, natrophobic grasses and broad-leaved plants ... | 2000 | 10717838 |
| dihydrofolate influences the activity of escherichia coli dihydrofolate reductase synthesised de novo. | the folding of proteins into their native structures is known to depend on molecular chaperones. however, other ligands or cofactors which still require characterisation are also likely to influence protein folding. the intention of this study was to reveal how the folding of an enzyme, escherichia coli dihydrofolate reductase, was affected by a substrate ligand, i.e. dihydrofolate. the enzyme was synthesised by coupled transcription/translation in a bacterial cell-free system. correct folding o ... | 2000 | 10716630 |
| catalase deficiency in staphylococcus aureus subsp. anaerobius is associated with natural loss-of-function mutations within the structural gene. | degenerate oligonucleotide primers based on internal peptide sequences obtained by hplc from purified staphylococcus aureus catalase were used to locate the s. aureus and s. aureus subsp. anaerobius kat regions by pcr. southern hybridization analysis with a probe derived from a 1.1 kb pcr-amplified fragment showed that a single copy of the putative catalase gene was present in the s. aureus and s. aureus subsp. anaerobius chromosome. the nucleotide sequence of s. aureus kata revealed a 1518 bp o ... | 2000 | 10708385 |
| differential induction of complement fragment c5a and inflammatory cytokines during intramammary infections with escherichia coli and staphylococcus aureus. | the prompt recruitment of neutrophils to the site of infection is essential for the defense of the bovine mammary gland against invading pathogens and is determinant for the outcome of the infection. escherichia coli is known to induce clinical mastitis, characterized by an intense neutrophil recruitment leading to the eradication of the bacteria, whereas staphylococcus aureus induces subclinical mastitis accompanied by a moderate neutrophil recruitment and the establishment of chronic mastitis. ... | 2000 | 10702487 |
| effect of endotoxin challenge on hepatic 5'-deiodinase activity in cattle. | thyroid status is compromised in a variety of acute and chronic infections and toxin-mediated disease states. conversion of thyroxine (t4) into the metabolically active hormone, triiodothyronine (t3), is catalyzed by 5'-deiodinase (5'd). our objective was to determine the effect of endotoxin (lps) challenge with and without l-arginine (arg) infusion on hepatic activity of 5'd and plasma concentrations of t4 and t3. in a 2 x 2 factorial, beef heifers (275-310 kg b.wt.) were fed low (8% cp; 6.5 kg ... | 2000 | 10701770 |
| clonal turnover of enterohemorrhagic escherichia coli o157:h7 in experimentally infected cattle. | a total of 401 enterohemorrhagic escherichia coli (ehec) o157:h7 isolates from two experimentally infected calves were analyzed using molecular biological methods. genetic differences detected by pulsed-field gel electrophoresis were observed between the inoculated and recovered strains as early as 1 day post inoculation. the loss of the inoculated clone was observed in one calf. replication and dissemination of the ehec o157:h7 strains that mutated in cattle may result in the diversification of ... | 2000 | 10689170 |
| subtypes of intimin among non-toxigenic escherichia coli from diarrheic calves in brazil. | one hundred and five strains of escherichia coli that were isolated from calves with diarrhea in the state of são paulo, brazil, and were negative for enterotoxins and cytotoxins, were examined for the eae gene. four (3.8%) strains were positive by polymerase chain reaction (pcr) and were shown to produce intimin by using western blot with specific antiserum against the conserved n-terminal region of intimin. subtyping of the intimins was done by pcr with specific primers and by western blot wit ... | 2000 | 10680651 |
| cloning and expression of glycolipid transfer protein from bovine and porcine brain. | glycolipid transfer protein (gltp) is a small (23-24 kda), basic protein (pi congruent with 9.0) that accelerates the intermembrane transfer of various glycolipids. here, we report the first cloning of cdnas that encode the bovine and porcine gltps. the cdna open reading frame for bovine gltp was constructed by bridge-overlapping extension polymerase chain reaction (pcr) after obtaining partial coding cdna clones by hot start, seminested, and rapid amplification of cdna ends-pcr. the cdna open r ... | 2000 | 10671554 |
| a longitudinal study of shiga-toxigenic escherichia coli (stec) prevalence in three australian diary herds. | over a 12 month period, 588 cattle faecal samples and 147 farm environmental samples from three dairy farms in southeast queensland were examined for the presence of shiga-toxigenic escherichia coli (stec). samples were screened for shiga toxin gene (stx) using pcr. samples positive for stx were filtered onto hydrophobic grid membrane filters and stec identified and isolated using colony hybridisation with a stx-specific dna probe. serotyping was performed to identify serogroups commonly associa ... | 2000 | 10665540 |
| purification and characterization of chitin-binding proteins from the hemolymph of sweet potato hornworm, agrius convolvuli. | three chitin-binding proteins (cbps: cbp9, cbp15, cbp66) were identified from the larval hemolymph of sweet potato hornworm, agrius convolvuli. two (cbp9 and cbp15) of them have been isolated and purified by gel filtration (superdex hr 75), cation-exchange chromatography (mono s), and reverse-phase chromatography (murpc pc 2.1/3). in experiments to detect cbps in hemolymph, we examined whether ionic strength and existence of bovine serum albumin in the incubation solution influenced binding affi ... | 1999 | 10665375 |
| rapid and sensitive detection of escherichia coli o157:h7 in bovine faeces by a multiplex pcr. | cattle are considered the major reservoir for escherichia coli o157:h7, one of the newly emerged foodborne human pathogens of animal origin and a leading cause of haemorrhagic colitis in humans. a sensitive test that can accurately and rapidly detect the organism in the food animal production environment is critically needed to monitor the emergence, transmission, and colonization of this pathogen in the animal reservoir. in this study, a novel multiplex polymerase chain reaction (pcr) assay was ... | 1999 | 10664910 |
| inhibition of protein phosphatase-1 by clavosines a and b. novel members of the calyculin family of toxins. | site-directed mutagenesis was used to investigate the mechanism of interaction between the catalytic subunit of human protein phosphatase-1 (pp-1cgamma) and members of the calyculin family of toxins. clavosines a and b are related to calyculins but are glycosylated with a trimethoxy rhamnose group. we provide experimental evidence implicating tyr-134 as an important residue in pp-1cgamma that mediates interactions with the calyculins. mutation of tyr-134 to phe, to prevent hydrogen bond formatio ... | 2000 | 10660582 |
| comparison of membrane filtration rates and hydrophobic grid membrane filter coliform and escherichia coli counts in food suspensions using paddle-type and pulsifier sample preparation procedures. | food suspensions prepared by pulsifier contained less debris and filtered 1.3x to 12x faster through hydrophobic grid membrane filters (hgmfs) than those prepared by stomacher 400. coliform and escherichia coli counts made by an hgmf method yielded 84 and 36 paired samples, respectively, positive by both suspending methods. overall counts of pulsificates and stomachates did not differ significantly for either analysis, though coliform counts by pulsifier were significantly higher in mushrooms an ... | 2000 | 10643783 |
| interventions to reduce microbiological contamination of beef variety meats. | hot water and solutions of acetic acid, lactic acid, or trisodium phosphate applied by immersion or spraying, chlorine solution applied by immersion, and exposure to steam in a pasteurization system, in a cabinet, or in combination with vacuum were evaluated for their effectiveness in reducing levels of bacterial contamination on samples of beef cheek meat, large intestine, lips, liver, oxtail, and tongue. treated samples (five per treatment) and controls were analyzed for aerobic plate counts ( ... | 2000 | 10643768 |
| effect of ph on survival, thermotolerance, and verotoxin production of escherichia coli o157:h7 during simulated fermentation and storage. | heat treatment is increasingly being introduced to fermented meat processing, since the acid tolerance properties of escherichia coli o157:h7 can permit this organism to survive traditional processing procedures. this study investigated the effect of growth ph and fermentation on the thermotolerance at 55 degrees c of e. coli o157:h7 in a model fermented meat system. e. coli o157:h7 (strain 380-94) was grown at ph 5.6 or 7.4 (18 h at 37 degrees c), fermented to ph 4.8 or 4.4 in brain heart infus ... | 2000 | 10643763 |
| phosphoserine aminotransferase, the second step-catalyzing enzyme for serine biosynthesis. | as a step toward analyzing the serine biosynthetic pathway in mammals, we have studied the properties of phosphoserine aminotransferase, the second step-catalyzing enzyme. the k(m) values for 3-phosphohydroxypyruvate and l-phosphoserine are 5 and 35 microm, respectively, and those for glutamate and alpha-ketoglutarate are 1.2 and 0.8 mm, respectively. the product inhibition studies strengthened the support for a ping-pong mechanism and allowed evaluation of ki values for the four substrates. the ... | 1999 | 10637769 |
| the effects of the surface charge and hydrophobicity of escherichia coli on its adhesion to beef muscle. | the surface characteristics of escherichia coli strains were studied to evaluate the effect upon bacterial adhesion to beef muscle. the influence of suspension conditions upon the surface charge of a pathogenic strain, e. coli o157:h7 (ec01), and a saprophytic laboratory strain, e. coli jm109 (ec22) were investigated and compared. the cellular surface charge of most e. coli o157:h7 strains were much less affected by changes in the ph, ionic strength or concentration of surfactants in the suspend ... | 1999 | 10634709 |
| prevalence of escherichia coli o157:h7 from cull dairy cows in new york state and comparison of culture methods used during preharvest food safety investigations. | a number of protocols for the cultural detection of escherichia coli o157:h7 in clinical fecal specimens have been proposed. in the present study direct plating of cattle feces was compared to three different broth enrichment protocols, i.e., a protocol with modified e. coli broth with novobiocin, a protocol with trypticase soy broth with cefixime and vancomycin, and a protocol with gram-negative broth with novobiocin, for their relative abilities to detect e. coli o157:h7 in feces. in all enric ... | 2000 | 10618108 |
| the influence of inorganic phosphate on the activity of adenosine kinase. | the enzyme adenosine kinase (ak; ec 2.7.1.20) shows a dependence upon inorganic phosphate (pi) for activity. the degree of dependence varies among enzyme sources and the ph at which the activity is measured. at physiological ph, recombinant ak from chinese hamster ovary (cho) cells and ak from beef liver (bl) show higher affinities for the substrate adenosine (ado), larger maximum velocities and lower sensitivities to substrate inhibition in the presence of pi. at ph 6.2, both bl and cho ak exhi ... | 2000 | 10606765 |
| typing of intimin genes in human and animal enterohemorrhagic and enteropathogenic escherichia coli: characterization of a new intimin variant. | enteropathogenic escherichia coli (epec) and enterohemorrhagic e. coli (ehec) produce the characteristic "attaching and effacing" (a/e) lesion of the brush border. intimin, an outer membrane protein encoded by eae, is responsible for the tight association of both pathogens with the host cell. several eae have been cloned from different epec and ehec strains isolated from humans and animals. these sequences are conserved in the n-terminal region but highly variable in the last c-terminal 280 amin ... | 2000 | 10603369 |
| crystal structure of the purine nucleoside phosphorylase (pnp) from cellulomonas sp. and its implication for the mechanism of trimeric pnps. | the three-dimensional structure of the trimeric purine nucleoside phosphorylase (pnp) from cellulomonas sp. has been determined by x-ray crystallography. the binary complex of the enzyme with orthophosphate was crystallized in the orthorhombic space group p212121 with unit cell dimensions a=64.1 a, b=108.9 a, c=119.3 a and an enzymatically active trimer in the asymmetric unit. x-ray data were collected at 4 degrees c using synchrotron radiation (embl/desy, hamburg). the structure was solved by m ... | 1999 | 10600382 |
| protective cultures inhibit growth of listeria monocytogenes and escherichia coli o157:h7 in cooked, sliced, vacuum- and gas-packaged meat. | contamination of cooked meat products with listeria monocytogenes poses a constant threat to the meat industry. the aim of this study was therefore to investigate the use of indigenous lactic acid bacteria (lab) as protective cultures in cooked meat products. cooked, sliced, vacuum- or gas-packaged ham and servelat sausage from nine meat factories in norway were inoculated with 10(3) cfu/g of a mixture of three rifampicin resistant (rif-mutant) strains of l. monocytogenes and stored at 8 degrees ... | 1999 | 10598113 |
| characterization of monoclonal antibodies against bovine herpesvirus 1 gd fusion protein expressed in e. coli. | a total of 20 hybridoma cell lines secreting monoclonal antibodies (mabs) against e. coli expressed bovine herpesvirus-1 (bhv-1) gd fusion protein were produced following the fusion of sp2/0 myeloma cells with splenocytes from balb/c mice immunized previously with immunoaffinity purified bhv-1 gd fusion protein. an indirect fluorescent antibody test (ifat) using bhv-1 infected mdbk cells was used for the selection of positive hybridomas secreting specific antibody. the monoclonal antibody isotyp ... | 1999 | 10598086 |
| lactoferrin concentration in milk of bovine clinical mastitis. | the lactoferrin (lf) concentration in the milk from dairy cows with clinical mastitis was determined to evaluate the relationship between the lf concentration (lfc) in milk and the non-specific defensive capability of the udder. the mean lfc in 368 milk samples from 319 cows with clinical mastitis was significantly higher (p < 0.01) than that of normal cows. the mean lfc in milk from quarters infected with mycoplasma bovis or staphylococcus aureus was significantly higher (p < 0.05) than that of ... | 1999 | 10598071 |
| mammalian mitochondrial ribosomal proteins (2). amino acid sequencing, characterization, and identification of corresponding gene sequences. | four different classes of mammalian mitochondrial ribosomal proteins were identified and characterized. mature proteins were purified from bovine liver and subjected to n-terminal or matrix-assisted laser-desorption mass spectroscopic amino acid sequencing after tryptic in-gel digestion and high pressure liquid chromatography separation of the resulting peptides. peptide sequences obtained were used to virtually screen expressed sequence tag data bases from human, mouse, and rat. consensus cdnas ... | 1999 | 10593885 |
| characterization of two fungal-elicitor-induced rice cdnas encoding functional homologues of the rab-specific gdp-dissociation inhibitor. | by using the mrna differential display approach to isolate defense signaling genes active at the early stage of fungal infection two cdna fragments with high sequence homology to rab-specific gdp-dissociation inhibitors (gdis) were identified in rice (oryza sativa l.) suspension cells. using polymerase-chain-reaction products as probes, two full-length cdna clones were isolated from a cdna library of fungal-elicitor-treated rice, and designated as osgdi1 and osgdi2. the deduced amino acid sequen ... | 1999 | 10592042 |
| high occurrence of shiga toxin-producing escherichia coli (stec) in healthy cattle in rio de janeiro state, brazil. | in order to evaluate the prevalence of shiga toxin-producing escherichia coli (stec) strains, 197 fecal samples of healthy cattle from 10 dairy farms, four beef farms and one slaughterhouse at rio de janeiro state, brazil, were examined for shiga toxin (stx) gene sequences by polymerase chain reaction (pcr). for presumptive isolation of o157:h7 e. coli, the cefixime-potassium tellurite-sorbitol macconkey agar (ct-smac) was used. a high occurrence (71%) of stx was detected, and was more frequentl ... | 1999 | 10591502 |
| unusual amino acid usage in the variable regions of mercury-binding antibodies. | monoclonal antibodies (mab) specific for mercuric ions were isolated from balb/c mice injected with a mercury-containing, hapten-carrier complex. the antibodies reacted by enzyme-linked immunosorbent assay with bovine serum albumin-glutathione-mercuric chloride (bsa-gsh-hgcl) but not with bsa-gsh without mercury. nucleotide sequences from polymerase chain reaction products encoding six of the antibody heavy-chain variable regions and seven light-chain variable regions revealed that all the antib ... | 1999 | 10591102 |
| agar underlay method for recovery of sublethally heat-injured bacteria. | a method of recovering sublethally heat-injured bacteria was developed. the procedure (termed the agar underlay method) uses a nonselective agar underlaid with a selective medium. in a two-chambered petri dish, the lutri plate (lp), a nonselective agar is inoculated with a population of sublethally heat-injured bacteria. after a 2-h repair incubation period, selective agar is added to the bottom chamber of the lp and incubated. by diffusing through the nonselective top agar, selective agents fro ... | 1999 | 10583985 |
| the effect of alpha-lactalbumin and beta-lactoglobulin hydrolysates on the metabolic activity of escherichia coli jm103. | bovine milk proteins alpha-lactalbumin (alpha-la) and beta-lactoglobulin (beta-lg) were hydrolysed with seven different proteolytic enzymes, and the effect of various hydrolysates on a genetically modified luminous escherichia coli jm103 was tested in vitro with a bioluminescence assay for bacterial growth and metabolism. undigested proteins did not inhibit the activity of tested e. coli jm103 at a concentration as high as 0.1 g ml-1. at the same concentrations, alpha-la hydrolysed with pepsin o ... | 1999 | 10583682 |
| occurrence of escherichia coli o157:h7 in hamburgers produced in brazil. | the occurrence of escherichia coli o157:h7 was evaluated in 886 samples of hamburgers produced by eight manufacturers in the south and southeast of brazil from january to september of 1997. the pathogen was not detected in any of the samples analyzed, although 17 (1.9%) showed the presence of e. coli strains, which presented agglutination with o157 antiserum. these strains were not confirmed, since a subsequent identification indicated that they were fermentation positive for sorbitol, incapable ... | 1999 | 10571325 |
| autoantibodies to brain components and antibodies to acinetobacter calcoaceticus are present in bovine spongiform encephalopathy. | bovine spongiform encephalopathy (bse) is a neurological disorder, predominantly of british cattle, which belongs to the group of transmissible spongiform encephalopathies together with creutzfeldt-jakob disease (cjd), kuru, and scrapie. autoantibodies to brain neurofilaments have been previously described in patients with cjd and kuru and in sheep affected by scrapie. spongiform-like changes have also been observed in chronic experimental allergic encephalomyelitis, at least in rabbits and guin ... | 1999 | 10569779 |
| genotoxic effects of benzyl isothiocyanate, a natural chemopreventive agent. | benzyl isothiocyanate (bitc) is contained in cruciferous plants which are part of the human diet. numerous reports indicate that bitc prevents chemically induced cancer in laboratory animals and it has been postulated that bitc might also be chemoprotective in humans. on the other hand, evidence is accumulating that this compound is a potent genotoxin in mammalian cells by itself. to further elucidate the potential hazards of bitc, we investigated its genotoxic effects in different in vitro geno ... | 1999 | 10567035 |
| [fecal shedding and serum antibody responses of cattle experimentally infected with enterohaemorrhagic escherichia coli o157:h7]. | 1999 | 10565127 | |
| comparative sensitivity of immunoassays for haptens using monomeric and dimeric antibody fragments. | a single-chain anti-atrazine antibody fragment, scab (single-chain fv with a ck domain), was expressed in escherichia coli, and monomeric and dimeric species were preferentially purified from periplasmic extracts by chromatography upon nickel chelate immunosorbent columns or by immunoaffinity purification using a constant domain (ck) tag. recombinant monomeric and dimeric antibody fragments, fab, and intact monoclonal antibodies were compared in assays by competition between free atrazine in sol ... | 1999 | 10563896 |
| experimental infection of calves with escherichia coli o157:h7. | three 3-month-old japanese black calves were experimentally infected with escherichia coli o157:h7 to define the magnitude (cfu/g) and duration of fecal shedding of the organism. in two of the three calves, fecal shedding of e. coli o157:h7 ceased in 5 and 9 weeks. the remaining calf continued shedding e. coli o157:h7 for more than 31 weeks, and the magnitude of the shedding ranged from 10(1) to 10(4) cfu/g of feces. the possibility is suggested that a percentage of animals naturally infected wi ... | 1999 | 10563303 |
| investigating site-specific effects of the -x glutamate in a parvalbumin cd site model peptide. | the -x glutamate in a 33-residue model peptide comprising the cd site of carp parvalbumin 4.25 (parvcd) was replaced with aspartate (parvcd-xd) and the effect on calcium-dependent dimerization and calcium affinity assessed. the peptide parvcd demonstrates a 10(5)-fold lower calcium affinity than the same site in the native protein. both the parvcd and parvcd-xd model peptides fail to bind magnesium. the low calcium affinity and failure of the model parvcd site to bind magnesium may be due to hig ... | 1999 | 10562419 |
| polycitone a, a novel and potent general inhibitor of retroviral reverse transcriptases and cellular dna polymerases. | polycitone a, an aromatic alkaloid isolated from the ascidian polycitor sp. exhibits potent inhibitory capacity of both rna- and dna-directed dna polymerases. the drug inhibits retroviral reverse transcriptase (rt) [i.e. of human immunodeficiency virus type 1 (hiv), murine leukaemia virus (mlv) and mouse mammary tumour virus (mmtv)] as efficiently as cellular dna polymerases (i.e. of both dna polymerases alpha and beta and escherichia coli dna polymerase i). the mode and mechanism of inhibition ... | 1999 | 10548537 |
| e. coli expressed proteins as diagnostic reagents for typing of foot-and-mouth disease virus. | truncated proteins corresponding to the c-terminal half of vp1 of four vaccine strains and two field variants of foot-and-mouth disease virus (fmdv) were expressed in e. coli. the expressed proteins were affinity purified and their type specific reactivity was confirmed by immunoprecipitation with anti-virus antibodies. antibodies were raised against the purified proteins in guinea pigs and the type specificity of the anti peptide antibodies was confirmed by antigen capture reverse transcription ... | 1999 | 10542020 |
| prevalence and infection risks of zoonotic enteropathogenic bacteria in swiss cow-calf farms. | a longitudinal study was performed in 67 larger swiss cow-calf farms from september 1996 through november 1997. the objectives of the study were to estimate prevalence and risk factors for colonization with potentially zoonotic enteropathogenic bacteria in younger calves and in calves at weaning age. the study included data from 395 calves with three to four fecal samples each. fecal samples were analyzed for campylobacter spp., verotoxin producing e. coli (vtec), yersinia spp. and salmonella sp ... | 1999 | 10535771 |
| reduction of escherichia coli o157:h7 by stimulated pediococcus acidilactici. | this study was conducted to determine if stimulating the growth of meat starter culture (pediococcus acidilactici) in a laboratory medium (brain heart infusion broth +2.3% nacl + 1.5% sucrose; lbhi) and during meat fermentation would control escherichia coli o157:h7. in lbhi medium without p. acidilactici, the numbers of e. coli o157:h7 increased from 4.00 to 8.34 log10 cfu ml-1, whereas in the presence of p. acidilactici (approximately 6.0 log10 cfu ml-1) in lbhi, lbhim (lbhi + 0.005% mnso4), l ... | 1999 | 10530043 |
| detection of low dose radiation induced dna damage using temperature differential fluorescence assay. | a rapid and sensitive fluorescence assay for radiation-induced dna damage is reported. changes in temperature-induced strand separation in both calf thymus dna and plasmid dna (puc 19 plasmid from escherichia coli) were measured after exposure to low doses of radiation. exposures of between 0.004 and 1 gy were measured with doses as low as 0.008 gy yielding significant responses. the double-strand, sensitive dye picogreen was used as an indicator of dna denaturation. calibration plots indicate t ... | 1999 | 10517153 |
| 1,25-dihydroxyvitamin d3 enhances milk antibody titers to escherichia coli j5 vaccine. | recent evidence in cattle and mice has suggested that 1,25-dihydroxyvitamin d3 may stimulate t-lymphocyte differentiation pathways responsible for humoral immunity. the use of 1,25-dihydroxyvitamin d3 as an adjuvant for an escherichia coli j5 vaccine was tested. ten midlactation cows received j5 vaccine and were revaccinated 6 wk after the first vaccine administration. five of these cows were given 200 micrograms of 1,25-dihydroxyvitamin d3, in addition to the primary vaccination, and they recei ... | 1999 | 10509248 |
| serological evidence of an australian bovine lentivirus. | recombinant 26 kda capsid (ca) proteins of bovine lentiviruses, bovine immunodeficiency virus (biv) and jembrana disease virus (jdv), were expressed in escherichia coli and utilised as antigens for an enzyme-linked immunosorbent assay (elisa) and a western immunoblot (wib) procedure for the detection of antibody in dairy cattle in western australia. a total of 690 serum samples, 30 from each of 23 farms, were tested by elisa with a jdv ca protein antigen, and antibody was detected in 3.8% (p<0.0 ... | 1999 | 10501174 |
| micellar electrokinetic chromatography as a complementary method to sodium dodecyl sulfate-polyacrylamide gel electrophoresis for studying limited proteolysis of proteins. | micellar electrokinetic chromatography (mekc) has been utilized as an analytical method to perform investigations on limited proteolysis of proteins. to this purpose partial proteolysis experiments with a series of proteinases were performed, utilizing as model protein pyruvate kinase (pk) from escherichia coli, an enzyme that is regulated allosterically by fructose 1,6-bisphosphate (fbp). data obtained with sodium dodecyl sulfate-polyacrylamide gel electrophoresis (sds-page) and mekc were compa ... | 1999 | 10499331 |
| use of heme-protein complexes by the yersinia enterocolitica hemr receptor: histidine residues are essential for receptor function. | the abilities of two bacterial active heme transporters, hmbr of neisseria meningitidis and hemr of yersinia enterocolitica, to use different heme sources were compared. while hmbr-expressing cells used only hemoglobin (hb) and heme, hemr-expressing bacteria were able to grow on hb, heme, myoglobin, hemopexin, catalase, human and bovine serum albumin-heme, and haptoglobin-hemoglobin complexes as sources of iron. expression of functional hemr allowed escherichia coli cells to respond to heme-cont ... | 1999 | 10498719 |
| production of engineered human pancreatic ribonucleases, solving expression and purification problems, and enhancing thermostability. | human pancreatic ribonuclease, the homolog of bovine pancreatic ribonuclease, has a significant therapeutic potential. its study has been hindered by the difficulty of obtaining the enzyme in a pure and homogeneous form, either from human source or using heterologous expression. engineering of different variants of human pancreatic ribonuclease has allowed us to study and overcome some problems encountered during its heterologous production in an escherichia coli system and its purification from ... | 1999 | 10497083 |
| prevalence of escherichia coli o157:h7 in white-tailed deer sharing rangeland with cattle. | to determine the prevalence of fecal shedding of escherichia coli o157:h7 in white-tailed deer (odocoileus virginianus) with access to cattle pastures. | 1999 | 10496130 |
| expression, purification, and crystal structure determination of recombinant human epidermal-type fatty acid binding protein. | we describe the crystal structure of human epidermal-type fatty acid binding protein (e-fabp) that was recently found to be highly upregulated in human psoriatic keratinocytes. to characterize e-fabp with respect to ligand-binding properties and tertiary structure, we cloned the respective cdna, overexpressed the protein in escherichia coli and purified it to homogeneity by a combination of ion-exchange and size-exclusion chromatographic steps with a yield of 30 mg/l broth. the purified protein ... | 1999 | 10493790 |
| activation of the cdc42 effector n-wasp by the shigella flexneri icsa protein promotes actin nucleation by arp2/3 complex and bacterial actin-based motility. | to propel itself in infected cells, the pathogen shigella flexneri subverts the cdc42-controlled machinery responsible for actin assembly during filopodia formation. using a combination of bacterial motility assays in platelet extracts with escherichia coli expressing the shigella icsa protein and in vitro analysis of reconstituted systems from purified proteins, we show here that the bacterial protein icsa binds n-wasp and activates it in a cdc42-like fashion. dramatic stimulation of actin asse ... | 1999 | 10491394 |
| expression of inducible nitric oxide synthase in spontaneous bovine bronchopneumonia. | the expression of inducible nitric oxide synthase (inos), major histocompatibility class ii molecules (mhc-ii), cd68, and the calcium-binding proteins s100a8 and s100a9 (also called mrp8 and mrp14, respectively) was assessed in lung tissues from cattle that succumbed to pneumonia. expression patterns of these markers were related to the types of lung lesion. inos expression was only observed in lungs infected with arcanobacterium pyogenes or pasteurella haemolytica but not in lungs from cattle w ... | 1999 | 10490207 |
| role of cryptosporidium parvum as a pathogen in neonatal diarrhoea complex in suckling and dairy calves in france. | this study was carried out to find the importance of cryptosporidium parvum in diarrhoea of neonatal calves in two types of breeding - suckling and dairy calves - in france. different agents causing neonatal diarrhoea, e. coli, rotavirus, coronavirus, salmonella and cryptosporidium were systematically researched in faeces. 1. suckling calves: in 40 livestock farms selected for diarrhoea, 311 calves 4 to 10 days old which had diarrhoea for less than 24h or no diarrhoea, were included in the study ... | 1999 | 10488727 |
| paua: a novel plasminogen activator from streptococcus uberis. | chromosomal dna from two geographically distinct isolates of streptococcus uberis was used to clone the plasminogen activator in an active form in escherichia coli. the cloned fragments from each strain contained four potential open reading frames (orfs). that for the plasminogen activator encoded a protein of 286 amino acids (33.4 kda) which is cleaved between residues 25 and 26 during secretion by s. uberis. the amino acid sequence of the mature protein showed only weak homology (23.5-28%) to ... | 1999 | 10483719 |
| prevalence of verotoxin-producing escherichia coli (vtec) in bovine coli mastitis and their antibiotic resistance patterns. | between december 1996 and october 1997, milk samples from a total of 145 cows with coli mastitis were screened for the presence of verotoxin-producing e. coli (vtec). vtec were found in four (2.8%) out of the 145 samples. the four isolated strains proved to be verotoxin (vt) 1-, vt2- or vt1- and vt2-positive. however, no strain contained all three virulence factors tested. further strain characterization was carried out by serotyping as well as by resistance pattern analysis. | 1999 | 10481626 |
| molecular definition and characterization of recombinant bovine cb8 and cb10: immunogenicity and arthritogenicity. | theoretically, the ability to produce recombinant type ii collagen (cii) peptide fragments in a prokaryotic expression system would be extremely useful for preparing adequate amounts of cii peptides suitable for therapeutic uses. bacteria do not contain the enzymes involved in the extensive posttranslational modifications that occur during the biosynthesis of cii, such as the hydroxylation of prolyl and lysyl residues and glycosylation of hydroxylysyl residues. as these posttranslational modific ... | 1999 | 10479530 |
| a reverse-sandwich enzyme-linked immunosorbent assay for verocytotoxin 1 and 2 antibodies in human and bovine sera. | a reverse-sandwich enzyme-linked immunosorbent assay (elisa), in which an antibody is sandwiched by antigens, was established for the titration of antibodies to verocytotoxins (vt) in human and animal sera. this assay has two advantages over a conventional indirect elisa: (i) higher specificity and sensitivity and (ii) the ability to comparably titrate antibodies from different species. the vt1 (shiga-like toxin 1) antibody-positive rates were 5% in 202 normal adult humans and 99% in 93 normal c ... | 1999 | 10473521 |
| hydrochloric acid treatment for rapid recovery of shiga toxin-producing escherichia coli o26, o111 and o157 from faeces, food and environmental samples. | we developed a hydrochloric acid treatment for the isolation of shiga toxin-producing escherichia coli (stec) o26:h11, o111:h- and o157:h7 strains from a variety of samples. after exposure to an equal volume of 1/8n hcl solution for 30 sec, the fecal suspensions and enrichment cultures were spread onto cefixime-tellurite-sorbitol-macconkey (ct-smac) agar. this hcl treatment increased the sensitivity for detection of stec o26:h11, o111:h- and o157:h7 strains and decreased the growth of other micr ... | 1999 | 10467660 |