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lactoferricin of bovine origin is more active than lactoferricins of human, murine and caprine origin.the antimicrobial peptide lactoferricin is generated by gastric pepsin cleavage of lactoferrin. we have examined the antimicrobial activity of lactoferricins derived from lactoferrin of human, murine, caprine and bovine origin with minimal inhibitory concentration (mic) and minimal bactericidal concentration (mbc) against e. coli atcc 25922 and s. aureus atcc 25923. we found that lactoferricin of bovine origin (lf-cin b) was the most efficacious of the lactoferricins tested. by comparing the lin ...199810066056
detection of escherichia coli o157:h7 from musca domestica (diptera: muscidae) at a cattle farm in japan.enterohemorrhagic escherichia coli (ehec) o157:h7 was isolated for the first time from musca domestica l. a total of 310 fly samples was collected from 4 different farms in obihiro-city, hokkaido, in the summer and autumn of 1997;5 samples carried e. coli serotype o157:h7. using elisa and vero cell cytotoxicity assay, 3 isolates from 1 cattle farm produced both active shiga-toxin type 1 (stx1) and 2 (stx2). these isolates also carried hemolysin and eaea genes and harbored the 90-kb virulence pla ...199910071501
modulation of the remote heme site geometry of recombinant mouse neuronal nitric-oxide synthase by the n-terminal hook region.the role of two essential residues at the n-terminal hook region of neuronal nitric-oxide synthase (nnos) in nitric-oxide synthase activity was investigated. full-length mouse nnos proteins containing single-point mutations of thr-315 and asp-314 to alanine were produced in the escherichia coli and baculovirus-insect cell expression systems. the molecular properties of the mutant proteins were analyzed in detail by biochemical, optical, and electron paramagnetic resonance spectroscopic technique ...199910075660
pattern of diarrhoea in newborn beef calves in south-west france.a prospective study was carried out on 94 randomly selected beef herds in the midi-pyrénées region in france. the objective was to describe diarrhoea and mortality in beef calves from birth to 30 days of age. calves (3,080) were followed from december 1995 to april 1996, and a total of 700 visits allowed records of herd management practices, individual data and environmental conditions to be collected. the incidence rate for diarrhoea during the neonatal period was 14.6%, and varied markedly bet ...199910081113
expression of bovine cytokines in escherichia coli.glutathione s-transferase fusion proteins of bovine interleukin-2 (il-2), il-4, il-6 and interferon-gamma (ifn-gamma) were expressed in escherichia coli. complementary dna (cdna) for open reading frame of each cytokine without signal peptide encoding region was amplified by reverse transcriptional polymerase chain reaction method and was subcloned into pgex-5x-1. in result, il-6 and ifn-gamma fusion proteins in bacteria were soluble, but il-2 and il-4 fusion proteins were insoluble. the insolubl ...199910081758
lipopolysaccharide enhances the production of vascular endothelial growth factor by human pulp cells in culture.we investigated whether vascular endothelial growth factor (vegf) production by human pulp cells (hpc) is regulated by lipopolysaccharide (lps) in relation to the pathogenesis of pulpitis. although hpc incubated with medium alone only marginally expressed vegf mrna and produced a low level of vegf as detected by enzyme-linked immunosorbent assay, the vegf mrna expression and vegf production were markedly enhanced upon stimulation with lps from escherichia coli. prevotella intermedia lps, phorbol ...199910084996
production, crystallization and diffraction to atomic resolution of an antibody fv specific for the blood-group a oligosaccharide antigen.the histoblood-group abo carbohydrate antigens are well known as important factors in blood transfusions, but they can also act as receptors for infectious agents and have been implicated in susceptibility to certain carcinomas. a single-chain variable-domain antigen-binding fragment (scfv) gene based on the known sequence of an anti-blood-group-a monoclonal antibody (ac1001) has been synthesized and expressed in escherichia coli. the purified scfv preparation existed primarily in the monomeric ...199810089537
effects of ph and acid resistance on the radiation resistance of enterohemorrhagic escherichia coli.the effects of ph and the induction of ph-dependent stationary-phase acid resistance on the radiation resistance of escherichia coli were determined for seven enterohemorrhagic strains and one nonenterohemorrhagic strain. the isolates were grown in acidogenic or nonacidogenic media to ph levels of approximately 4.7 and 7.2, respectively. the cells were then transferred to brain heart infusion (bhi) broth adjusted to ph 4.0, 4.5, 5.0, and 5.5 (with hcl) that was preequilibrated to 2 degrees c, an ...199910090239
a recombinant bovine gallbladder mucin polypeptide binds biliary lipids and accelerates cholesterol crystal appearance time.mucin has a central role in the pathogenesis of cholesterol gallstones, in part because of its ability to bind biliary lipids and accelerate cholesterol crystal appearance time. previous studies have localized these properties to nonglycosylated mucin domains, and we have recently shown that these domains contain a series of 127-amino acid, cysteine-rich repeats. the aim of this study was to express a recombinant mucin polypeptide containing these repeats and investigate its lipid-binding and pr ...199910092316
recombinant production and purification of novel antisense antimicrobial peptide in escherichia coli.a fusion protein was genetically engineered that contains an antimicrobial peptide, designated p2, at its carboxy terminus and bovine prochymosin at its amino terminus. bovine prochymosin was chosen as the fusion partner because of its complete insolubility in escherichia coli, a property utilized to protect the cells from the toxic effects of the antimicrobial peptide. this fusion protein was purified by centrifugation as an insoluble inclusion body. a methionine linker between prochymosin and ...199810099178
characterization of the cardiac holotroponin complex reconstituted from native cardiac troponin t and recombinant i and c.cardiac troponin i (ctni), the inhibitory subunit of cardiac troponin (ctn), is phosphorylated by the camp-dependent protein kinase a at two adjacently located serine residues within the heart-specific n-terminal elongation. four different phosphorylation states can be formed. to investigate each monophosphorylated form ctni mutants, in which each of the two serine residues is replaced by an alanine, were generated. these mutants, as well as the wild-type cardiac troponin i (ctni-wt) have been e ...199910103031
real-time monitoring of escherichia coli o157:h7 adherence to beef carcass surface tissues with a bioluminescent reporter.a method for studying bacteria that are attached to carcass surfaces would eliminate the need for exogenous sampling and would facilitate understanding the interaction of potential human food-borne pathogens with food animal tissue surfaces. we describe such a method in which we used a bioluminescent reporter strain of escherichia coli o157:h7 that was constructed by transformation with plasmid pcgls1, an expression vector that contains a complete bacterial luciferase (lux) operon. beef carcass ...199910103275
catalase hpii from escherichia coli exhibits enhanced resistance to denaturation.catalase hpii from escherichia coli is a homotetramer of 753 residue subunits. the multimer displays a number of unusual structural features, including interwoven subunits and a covalent bond between tyr415 and his392, that would contribute to its rigidity and stability. as the temperature of a solution of hpii in 50 mm potassium phosphate buffer (ph 7) is raised from 50 to 92 degrees c, the enzyme begins to lose activity at 78 degrees c and 50% inactivation has occurred at 83 degrees c. the ina ...199910194300
a mutation in the heterotrimeric stimulatory guanine nucleotide binding protein alpha-subunit with impaired receptor-mediated activation because of elevated gtpase activity.it has been reported that substitution of arg258, a residue within the gtpase domain of the heterotrimeric guanine nucleotide binding protein (g protein) alpha-subunit (alphas), to alanine (alphas-r258a) results in decreased activation by receptor or aluminum fluoride (alf4-) and increased basal gdp release. arg258 interacts with gln170 in the helical domain, and, presumably, loss of this interaction between the gtpase and helical domain leads to more rapid gdp release, resulting in decreased ac ...199910200251
chloroplast nadh dehydrogenase from pisum sativum: characterization of its activity and cloning of ndhk gene.the pea chloroplast ndhk gene coding for a component of a nadh-plastoquinone oxidoreductase has been cloned and sequenced. this gene codes for a polypeptide of 227 amino acids and a predicted molecular mass of 25,495 da which belongs to the family of the 20 kda psst subunit of the bovine mitochondrial complex i. a fragment of this gene has been overexpressed in escherichia coli, and antibodies against the expressed polypeptide recognize a protein of the predicted molecular mass from pea thylakoi ...199910202810
detection of multidrug-resistant salmonella enterica serotype typhimurium dt104 based on a gene which confers cross-resistance to florfenicol and chloramphenicol.salmonella enterica serotype typhimurium (s. typhimurium) dt104 (dt104) first emerged as a major pathogen in europe and is characterized by its pentadrug-resistant pattern. it has also been associated with outbreaks in the united states. the organism typically carries resistance to ampicillin, chloramphenicol, streptomycin, sulfonamides, and tetracycline. the mechanism of chloramphenicol resistance in dt104 was determined by producing antibiotic-resistant escherichia coli host strain clones from ...199910203484
effect of antibiotic induced bacterial clearance in the udder on l-selectin shedding of blood neutrophils in cows with escherichia coli mastitis.bacterial clearance, l-selectin adhesion receptor expression and neutrophil recruitment during experimentally induced escherichia coli mastitis were investigated. acute mastitis was induced by injection of 10(4) cfu e. coli into both left quarters of 12 clinically healthy lactating cows, 2-6 weeks after parturition. half the cows were treated intravenously 10 h after infection, and subcutaneously 30 h after infection with enrofloxacin. in both groups, bacterial count, milk serum albumin, milk so ...199910206204
antibacterial activity of gentamicin and ciprofloxacin against gram-negative bacteria: interactions with pig and calf sera.the antibacterial activity of pig and calf serum and its ability to interact with gentamicin and ciprofloxacin were studied in vitro using escherichia coli k-12, proteus rettgeri (sanelli) and klebsiella pneumoniae atcc 10031. the antimicrobial activity of the above drugs, alone or in combination with serum, was investigated by the checkerboard method and expressed as the minimal inhibitory concentration (microg ml-1). pig serum (25%) with gentamicin had a synergistic antibacterial effect agains ...199910208763
unusual sites of arginine methylation in poly(a)-binding protein ii and in vitro methylation by protein arginine methyltransferases prmt1 and prmt3.arginine methylation is a post-translational modification found mostly in rna-binding proteins. poly(a)-binding protein ii from calf thymus was shown by mass spectrometry and sequencing to contain ng, ng-dimethylarginine at 13 positions in its amino acid sequence. two additional arginine residues were partially methylated. almost all of the modified residues were found in arg-xaa-arg clusters in the c terminus of the protein. these motifs are distinct from arg-gly-gly motifs that have been previ ...199910224081
molecular cloning of a novel human collectin from liver (cl-l1).collectins are a c-lectin family with collagen-like sequences and carbohydrate recognition domains. these proteins can bind to carbohydrate antigens of microorganisms and inhibit their infection by direct neutralization and agglutination, the activation of complement through the lectin pathway, and opsonization by collectin receptors. here we report the cloning of a cdna encoding human collectin from liver (cl-l1 (collectin liver 1)) that has typical collectin structural characteristics, consist ...199910224141
shiga toxin 1 from escherichia coli blocks activation and proliferation of bovine lymphocyte subpopulations in vitro.shiga toxin-producing escherichia coli (stec) is widespread in the cattle population, but the clinical significance of shiga toxins (stx's) for the bovine species remains obscure. since stx's exert immunomodulating effects in other species, we examined the effect of purified stx1 on a bovine b lymphoma cell line (bl-3) and peripheral blood mononuclear cells (pbmc) isolated from adult bovine blood by viability assays and flow cytometry analysis. stx1 markedly induced apoptosis in stimulated bl-3 ...199910225876
synthesis and serological characterization of l-glycero-alpha-d-manno-heptopyranose-containing di- and tri-saccharides of the non-reducing terminus of the escherichia coli k-12 lps core oligosaccharide.synthesis of the title trisaccharide was accomplished by sugar chain extension starting from the non-reducing terminus: coupling of glcp nac with ld-hepp, then adding glcp-oall. an alternative route started from the reducing end: coupling of ld-hepp with glcp-oall, then addition of glcp nac. in the synthesis of the title disaccharide a modification of the first approach was employed. the allyl glycosides were coupled with cysteamine, activated with thiophosgene and conjugated to bovine serum alb ...199810230038
interactions of the papovavirus dna replication initiator proteins, bovine papillomavirus type 1 e1 and simian virus 40 large t antigen, with human replication protein a.papovaviruses utilize predominantly cellular dna replication proteins to replicate their own viral genomes. to appropriate the cellular dna replication machinery, simian virus 40 (sv40) large t antigen (tag) binds to three different cellular replication proteins, the dna polymerase alpha-primase complex, the replication protein a (rpa) complex, and topoisomerase i. the functionally similar papillomavirus e1 protein has also been shown to bind to the dna polymerase alpha-primase complex. enzyme-l ...199910233951
patterning cells and their environments using multiple laminar fluid flows in capillary networks.this paper describes the use of laminar flow of liquids in capillary systems to pattern the cell culture substrate, to perform patterned cell deposition, and to pattern the cell culture media. we demonstrate the patterning of the cell culture substrate with different proteins, the patterning of different types of cells adjacent to each other, the patterned delivery of chemicals to adhered cells, and performing enzymatic reactions over select cells or over a portion of a cell. this method offers ...199910318920
evaluation of the role of endotoxin and cortisol on modulation of cd18 adhesion receptors in cows with mastitis caused by escherichia coli.to determine the effect of mastitis caused by escherichia coli on expression of cd18 cell surface receptors and to evaluate the involvement and regulation of receptors by lipopolysaccharide (lps) and cortisol.199910328420
expression of recombinant bovine l-selectin in escherichia coli and insect cells.bovine l-selectin was expressed in bacteria using pgex vector and in insect cells infected with recombinant baculovirus in order to obtain recombinant protein for preparation of specific antiserum and its functional studies. in bacterial expression, l-selectin fusion protein with glutathione s-transferase was detected in the insoluble fraction with the expected molecular weight of 60 kda by sds-page and reacted with anti-bovine cd62l monoclonal antibody in immunoblot analysis. in insect cells in ...199910331197
activation of toxin adp-ribosyltransferases by eukaryotic adp-ribosylation factors.adp-ribosylation factors (arfs) are members of a multigene family of 20-kda guanine nucleotide-binding proteins that are regulatory components in several pathways of intracellular vesicular trafficking. the relatively small (approximately 180-amino acids) arf proteins interact with a variety of molecules (in addition to gtp/gdp, of course). cholera toxin was the first to be recognized, hence the name. later it was shown that arf also activates phospholipase d. different parts of the molecule are ...199910331652
recombinant chicken ifn-gamma expressed in escherichia coli: analysis of c-terminal truncation and effect on biologic activity.interferon-gamma (ifn-gamma) possesses potent immunostimulatory properties, and it has recently been shown to have potential therapeutic properties. recombinant protein technology is frequently used for commercial production of therapeutics, such as ifn. biologically active recombinant chicken ifn-gamma (rchifn-gamma) constructs bearing an n-terminal poly-his tag were expressed in escherichia coli. preparations of rchifn-gamma contained varying ratios of a full-length and a truncated protein spe ...199910334390
genomic dna restriction site heterogeneity in bovine pasteurella multocida serogroup a isolates detected with an rrna probe.a total of 81 pasteurella multocida isolates from healthy and diseased dairy and beef cattle originating from various geographical locations was examined by rrna gene restriction site polymorphism analysis (ribotyping), restriction endonuclease analysis (rea), sds-page analysis of whole-cell (wcp) and outer-membrane (omp) proteins, and capsule and somatic serotyping. bacterial strains were isolated from nose, lung and in one case testicle, of holstein and cross-bred beef cattle. the isolates rep ...199910334595
new general approach for determining the solution structure of a ligand bound weakly to a receptor: structure of a fibrinogen aalpha-like peptide bound to thrombin (s195a) obtained using noe distance constraints and an ecepp/3 flexible docking program.a new approach incorporating flexible docking simulations and nmr data is presented for calculating the bound conformation of a ligand that interacts weakly with an enzyme. this approach consists of sampling directly the conformation of a flexible ligand inside a receptor active site containing surrounding flexible loops. to make this sampling efficient, a ligand-growing procedure has been adopted. optimization of the ecepp/3-plus-noe constraint function is carried out by using a collective vari ...199910336381
[detection of pas gene in shiga toxin producing escherichia coli (stec)].results of detection of the pas gene in 10 shigatoxin-producing escherichia coli strains (stec) isolated from foods (raw milk, certified milk, and beef) and in 18 enterohaemorrhagic escherichia coli strains (ehec) isolated from stool samples of patients suffering from hus, diarrhea or from carriers without symptoms are given. all isolates showed the eae gene coding for intimin. we could make sure by using pcr that all isolates showed the pas gene, too. this gene is a factor mainly responsible fo ...199910337054
the use of non-immune plasma powder in the prophylaxis of neonatal escherichia coli diarrhoea in calves.the protective use of plasma powder from cattle and swine against experimentally induced neonatal e. coli diarrhoea in colostrum-deprived calves was examined. diarrhoea was induced with a strain expressing f5+ fimbriae and a strain expressing f17+ fimbriae. in all groups supplemented with bovine plasma powder, diarrhoea and fever were less severe than in the control groups. for the groups infected with the f5+ e. coli strain, a reduction in excretion of the challenge strain by 2-4 orders of magn ...199910337234
growth of starved escherichia coli o157 cells in selective and non-selective media.escherichia coli o157 strains starved in sterile deionized water (sdw) and filter-sterilized natural river water (srw) were investigated with specific reference to their culturability in selective and non-selective media. growth of the strains starved in both sdw and srw were markedly suppressed with time in selective liquid media such as modified trypticase soy broth supplemented with novobiocin (mtsb+n) and modified e. coli broth supplemented with novobiocin (mec+n). this suppression was more ...199910338190
incidence of salmonella on beef carcasses relating to the u.s. meat and poultry inspection regulations.this article is part of a major study designed to collect baseline contamination data by sampling beef carcasses in seven slaughtering plants (four steer-heifer and three cow-bull plants) during both a dry season (november to january) and a wet season (may to june). samples (n = 30) were excised from each of three carcass anatomical sites (brisket, flank, and rump) at each of three points in the slaughtering chain (pre-evisceration, following final carcass washing, after 24-h carcass chilling). ...199910340666
infection of gnotobiotic calves with escherichia coli o157:h7 strain a84.six colostrum-deprived, hysterotomy-derived calves were maintained under sterile conditions and fed a milk replacer diet. at five days of age, five of the calves were dosed orally with 10(9) cfu of escherichia coli o157:h7 strain a84. they were killed after, one, two, six, 12 and 24 days, and samples were taken for bacteriological and pathological examination. the sixth uninfected control calf was killed at seven days of age and matched samples were taken for pathological comparison. the animals ...199910358875
identification of the rna-binding, dimerization, and eif4gi-binding domains of rotavirus nonstructural protein nsp3.the rotavirus nonstructural protein nsp3 is a sequence-specific rna binding protein that binds the nonpolyadenylated 3' end of the rotavirus mrnas. nsp3 also interacts with the translation initiation factor eif4gi and competes with the poly(a) binding protein. deletion mutations and point mutations of nsp3 from group a rotavirus (nsp3a), expressed in escherichia coli, indicate that the rna binding domain lies between amino acids 4 and 149. similar results were obtained with nsp3 from group c rot ...199910364288
afa and f17 adhesins produced by pathogenic escherichia coli strains in domestic animals.afa and f17 are afimbrial and fimbrial adhesins, respectively, produced by pathogenic escherichia coli strains in domestic animals. f17-related fimbriae are mainly detected on bovine and ovine e. coli associated with diarrhoea or septicaemia. the f17-g adhesin subunits recognize n-acetyl-d-glucosamine (glcnac) receptors present on bovine intestinal cells. some f17 subtypes also bind to glcnac receptors present on human uroepithelial and intestinal caco-2 cells or to the laminin contained in the ...199910367361
[udder health on dairy farms. 1. results of a longitudinal study on 300 dutch farms].udder health was studied in 300 dairy herds grouped in three categories according to the bulk milk somatic cell count. in all herds, lactating cows were housed in a free-stall barn during the winter. all herds participated in a three or four-weekly milk recording system, had annual production quota between 300,000 and 900,000 kg, and were stocked with cows of the holstein-friesian or dutch friesian breeds. the incidence of clinical mastitis was not different among herds with a low (< or = 150,00 ...199910372420
role of lactosyl glycan sequences in inhibiting enteropathogenic escherichia coli attachment.previously, we found that asialo-lactosamine sequences served as receptors for enteropathogenic escherichia coli (epec) binding to chinese hamster ovary (cho) cells. in the present report, we have extended these earlier results by examining the ability of lactosamine- or fucosylated lactosamine-bovine serum albumin (bsa) glycoconjugates to inhibit epec, strain e2348/69, binding to hep-2 cells. we found that, consistent with our previous findings with cho cells, n-acetyllactosamine-bsa was the mo ...199910377105
assessment of the microbiological conditions of tails, tongues, and head meats at two beef-packing plants.newly skinned tails of beef carcasses at two packing plants were similarly contaminated with total aerobes and with coliforms that were largely escherichia coli at log mean numbers about 3.5/cm2 and 4.5/100 cm2, respectively. the log mean numbers of aerobes and coliforms on the skinned tails after washing at plant a were, respectively, 1 and 2 log units less than the numbers on the newly skinned tails. at plant b, the log mean numbers of aerobes on skinned and on washed tails were similar while ...199910382660
[prevalence and serotypes of verocytotoxin-producing escherichia coli (vtec) isolates from dairy cattle].to clarify the source of infection and route of transmission of verocytotoxin-producing escherichia coli (vtec) in humans, we collected fresh feces from healthy dairy cattle reared in hokkaido, fukushima, kanagawa and okinawa prefectures between june 1996 and march 1997, and attempted to isolate vtec. the results are described below. 1) vtec was isolated from 68 (27.1%) of 251 fecal samples tested. vtec was isolated from 14 (28.0%) of 50 in hokkaido, 13 (26.0%) of 50 in fukushima, 20 (39.2%) of ...199910386024
effect of cattle diet on escherichia coli o157:h7 acid resistance.the duration of shedding of escherichia coli o157 isolates by hay-fed and grain-fed steers experimentally inoculated with e. coli o157:h7 was compared, as well as the acid resistance of the bacteria. the hay-fed animals shed e. coli o157 longer than the grain-fed animals, and irrespective of diet, these bacteria were equally acid resistant. feeding cattle hay may increase human infections with e. coli o157:h7.199910388727
shiga toxin-producing escherichia coli o157 in feedlot cattle and norwegian rats from a large-scale farm.a total of 365 faecal samples from different categories of cattle, 12 samples of untreated slurry, 50 samples of fresh droppings of feral domestic pigeons, 20 samples of fresh droppings of domestic sparrows and stool samples of 19 synanthropic rodents were examined for the presence of escherichia coli by broth enrichment culture and a subsequent immunomagnetic separation. escherichia coli o157 was found in 72 (20%) bovine samples, six (50%) samples of untreated slurry and four (40%) of 10 rats ( ...199910389259
peroxynitrite-mediated modification of proteins at physiological carbon dioxide concentration: ph dependence of carbonyl formation, tyrosine nitration, and methionine oxidation.the ability of peroxynitrite to modify amino acid residues in glutamine synthetase (gs) and bsa is greatly influenced by ph and co2. at physiological concentrations of co2 (1.3 mm), the generation of carbonyl groups (0.2-0.4 equivalents/subunit) is little affected by ph over the range of 7.2-9.0, but, in the absence of co2, carbonyl formation increases (from 0.1- 1.2 equivalents/subunit) as the ph is raised from 7.2 to 10.5. this increase is attributable, in part but not entirely, to the increas ...199910393903
decay-accelerating factor and cytoskeleton redistribution pattern in hela cells infected with recombinant escherichia coli strains expressing dr family of adhesins.escherichia coli strains expressing dr fimbriae are able to enter epithelial cells by interacting with a complement-regulatory protein, decay-accelerating factor. this model of bacterial internalization, with a well-characterized bacterial ligand and host receptor, provides a unique opportunity to investigate the early stages of invasion. we used immunofluorescence staining techniques to examine the distribution of receptor and cytoskeletal proteins in hela cells infected with e. coli recombinan ...199910417165
purification and properties of proline-rich antimicrobial peptides from sheep and goat leukocytes.we purified three proline-rich antimicrobial peptides from elastase-treated extracts of sheep and goat leukocytes and subjected two of them, oabac5alpha and chbac5, to detailed analysis. oabac5alpha and chbac5 were homologous to each other and to bovine bac5. both exhibited potent, broad-spectrum antimicrobial activity under low-concentration salt conditions. while the peptides remained active against escherichia coli, pseudomonas aeruginosa, bacillus subtilis, and listeria monocytogenes in 100 ...199910417180
acute phase response in dairy cows with experimentally induced escherichia coli mastitis.six finnish ayrshire cows were challenged intramammarily with 1500 cfu of escherichia coli (e. coli) into single udder quarters, and the challenge was repeated into contralateral quarters 3 weeks later. all cows received flunixine meglumine once, and 3 of them were also treated with enrofloxacin. at the 2nd challenge, treatments were changed vice versa. the development of mastitis was followed by monitoring of systemic and local clinical signs, and with serial milk and serum samples. intramammar ...199910418194
isolation of verocytotoxin-producing escherichia coli o157:h7 from cattle at slaughter in italy.cattle arriving for slaughter at a large abattoir in northern italy between april 1997 and january 1998 were examined for intestinal carriage of verocytotoxin-producing escherichia coli (vtec) o157 using an immunomagnetic separation technique. sixty sorbitol non-fermenting vtec o157 strains were isolated from 59 (13.1%) of the 450 cattle examined. in particular, vtec o157 was found in 37 (16.6%) of 223 feedlot cattle and in 22 (16.1%) of 137 dairy cull cows, but not in the 90 veal calves sampled ...199910418874
factors associated with fecal shedding of verotoxin-producing escherichia coli o157 on dairy farms.fecal samples were collected from 4,361 dairy cows on 91 dairy operations between 26 february and 8 july 1996. fecal samples were cultured for escherichia coli o157, and positive isolates were probed for verotoxin-producing genes. a total of 52 (1.2%) fecal samples on 22 (24.2%) operations were positive for verotoxin-producing e. coli o157. herds in which samples were collected on or after 1 may 1996 were significantly more likely to test positive than herds sampled before that date (odds ratio ...199910419200
antibacterial effect of lactoferricin b on escherichia coli o157:h7 in ground beef.the antibacterial activity of lactoferricin b on enterohemorrhagic escherichia coli o157:h7 in 1% peptone medium and ground beef was studied at 4 and 10 degrees c. in 1% peptone medium, 50 and 100 microg of lactoferricin b per ml reduced e. coli o157:h7 populations by approximately 0.7 and 2.0 log cfu/ml, respectively. studies comparing the antibacterial effect of lactoferricin b on e. coli o157:h7 in 1% peptone at ph 5.5 and 7.2 did not reveal any significant difference (p > 0.5) at the two ph ...199910419266
excretion of vtec o157 by cattle. 199910420488
a chromogenic plating medium for isolating escherichia coli o157:h7 from beef.there was no significant difference (p > 0.05) in the percentages of escherichia coli o157:h7 cells recovered on bcm o157:h7 (+) agar (69.7%) and macconkey sorbitol agar containing 5-bromo-4-chloro-3-indoxyl-beta-d-glucuronic acid (msa-bcig) (76.8%) vs tryptic soy agar. three e. coli o157:h7 strains (atcc 35150, 43890 and 43894) were separately inoculated into raw ground beef at low (mean 0.32 cfu g-1) and high (mean 3.12 cfu g-1) levels. using the united states department of agriculture (usda) ...199910432628
antibodies produced by mice immunized with recombinant vaccinia viruses expressing two different types of a major theileria sergenti surface antigen (p32) react with the native surface antigen.a 32 kda major surface antigen, p32, of theileria sergenti at the piroplasm stage is the main target of the host immune response. the immunogenic property of the p32 varies in some strains among the population of theileria sergenti in japan where the chitose type and the ikeda type are the most common varieties. we have constructed vaccinia virus recombinants vv/p32c and vv/p32i which harbor the chitose and ikeda types of p32 gene, respectively. it was found that vv/p32c and vv/p32i produced typ ...199910435791
stability, activity and flexibility in alpha-lactalbumin.alpha-lactalbumins and the type-c lysozymes are homologues with similar folds that differ in function and stability. to determine if the lower stability of alpha-lactalbumin results from specific substitutions required for its adaptation to a new function, the effects of lysozyme-based and other substitutions on thermal stability were determined. unblocking the upper cleft in alpha-lactalbumin by replacing tyr103 with ala, perturbs stability and structure but pro, which also generates an open cl ...199910436084
the metal function in the reactions of bovine serum amine oxidase with substrates and hydrazine inhibitors.bovine serum amine oxidase (bsao) reacts with 2-hydrazinopyridine, which binds the organic co-factor 2,4,5-trihydroxyphenylalanine quinone, forming a band at 435 nm. the band shifts to 526 nm around 60 degrees c, to 415 nm upon denaturation, but only shifts to 429 nm upon cu2+ depletion. its wavelength and intensity suggest that the adduct has the azo conformation, whilst the same adduct of crystalline escherichia coli amine oxidase (ecao) shows the hydrazone conformation in the x-ray structure. ...199910439080
semi-automated fluorogenic pcr assays (taqman) forrapid detection of escherichia coli o157:h7 and other shiga toxigenic e. coli.semi-automated detection of enterohaemorrhagic escherichia coli (ehec) o157:h7 and non-o157:h7 shiga toxin-producing e. coli (stec) was achieved using fluorogenic polymerase chain reaction (pcr). these pcr assays were designed to amplify 80, 120 and 150 bp regions of virulence genes stx1, stx2 and eaea, respectively, using specific primers. the fluorogenic probes were used for specific detection of amplified products of the stx1 and stx2 genes of stec, and the eaea gene of ehec o157:h7. for mult ...199910441202
antibacterial effects of lactoferricin b.the antimicrobial peptide, lactoferricin, can be generated upon gastric pepsin cleavage of lactoferrin. we have examined the inhibitory efficacy of lactoferricin of bovine origin (lf-cin b) on escherichia coli, proteus mirabilis and staphylococcus aureus with or without a cell wall. we found that spheroplasts and protoplasts had a lower mic than their counterparts with a cell wall. we also compared the efficacies of lf-cin b (17-31) made of all l-amino acids and all d-amino acids. the peptide ma ...199910447329
the role of the amino-terminal beta-barrel domain of the alpha and beta subunits in the yeast f1-atpase.the crystal structure of mitochondrial f1-atpase indicates that the alpha and beta subunits fold into a structure defined by three domains: the top beta-barrel domain, the middle nucleotide-binding domain, and the c-terminal alpha-helix bundle domain (abrahams et al., 1994); bianchet et al., 1998). the beta-barrel domains of the alpha and beta subunits form a crown structure at the top of f1, which was suggested to stabilize it (abrahams et al. 1994). in this study, the role of the beta-barrel d ...199910449236
genetic subtyping of escherichia coli o157 isolates from 41 pacific northwest usa cattle farms.escherichia coli o157 (n = 376) from 41 cattle farms were subtyped using pulsed field gel electrophoresis of endonuclease cleaved chromosomal dna. cleavage with xbai resulted in 81 subtypes. fifty-one isolates from subtypes found in more than one herd, or in herds on multiple sample collection dates were compared using the endonuclease noti, resulting in 23 additional subtypes. up to 11 xbai subtypes were found per farm with up to 7 subtypes/farm identified from a single date. indistinguishable ...199910459653
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 ...199910467660
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 ...199910473521
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 ...199910479530
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.199910481626
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 ...199910483719
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 ...199910488727
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 ...199910490207
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 ...199910491394
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 ...199910493790
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.199910496130
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 ...199910497083
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 ...199910498719
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 ...199910499331
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 ...199910501174
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 ...199910509248
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 ...199910517153
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 ...199910530043
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 ...199910535771
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 ...199910542020
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 ...199910548537
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 ...199910562419
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 ...199910563303
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 ...199910563896
[fecal shedding and serum antibody responses of cattle experimentally infected with enterohaemorrhagic escherichia coli o157:h7]. 199910565127
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 ...199910567035
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 ...199910569779
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 ...199910571325
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 ...199910583682
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 ...199910583985
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 ...199910591102
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 ...199910591502
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 ...199910592042
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 ...199910593885
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 ...199910598071
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 ...199910598086
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 ...199910598113
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 ...199910600382
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 ...200010603369
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 ...200010606765
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 ...200010618108
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 ...199910634709
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