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clinical pharmacology of oxolinic acid in young dairy calves.the in vitro sensitivity to oxolinic acid shown by pathogenic gram-negative bacterial isolates from young calves with diarrhea, pneumonia, and septicemia was investigated by the bute dilution method. minimal bactericidal concentrations of the drug for 65.5% of the isolates were less than or equal to 1.56 mug/ml and for 90%, less than or equal to 6.25 mug/ml. cross resistance between oxolinic acid and chloramphenicol, streptomycin, neomycin, colistin, ampicillin, gentamicin, and oxytetracycline w ...1976776048
anomalous reaction of 4-chloro-7-nitrobenzofurazan with thiol compounds.the kinetics of reaction of 4-chloro-7-nitrobenzofurazan with thiol groups at ph values above 5 cannot be accounted for solely on the basis of formation of a single product, the 4-thio derivative. spectroscopic observations indicate that, in addition to the 4-thio derivative, at least two other products are formed. one of these, referred to as p1, is most likely a reversible complex of thiol compound and 4-chloro-7-nitrobenzofurazan of the meisenheimer type. the other product, p2, which forms pr ...1979435240
conjugated polyene fatty acids as fluorescent membrane probes: model system studies.the use of conjugated polyene fatty acids as probes of membrane structure is examined, alpha- and beta-parinaric acid (cis, trans, trans, cis- and all trans-9, 11, 13, 15-octadecatetraenoic acid) and synthetic lecithins containing an alpha-parinaric acid chai in position 2 have been prepared, and their absorption and fluorescence properties have been determined. their absorption spectra are at sufficiently long wavelength to be unobscured by cellular chromophores such as nucleotides and aromatic ...1976778493
inactivation by detergents of the proline transport system in membrane vesicles from escherichia coli and its reactivation by bovine serum albumin.the proline transport system of membrane vesicles from escherichia coli was inactivated by a low concentration of detergents such as deoxycholate, dodecyl sulfate and triton x-100. the addition of a large amount of bovine serum albumin to membrane vesicles which had been treated with one of these detergents resulted in the restoration of the proline transport activity. the restoration of the transport activity by bovine serum albumain was most remarkable with the deoxycholate-inactivated membran ...1976764873
vaccination of the dam by the intramuscular or deep subcutaneous route to prevent neonatal calf enteric colibacillosis.comparison of colostrum-induced immunities in calves was made by challenge exposure with escherichia coli. these calves were delivered of cows which were vaccinated intramuscularly or deep subcutaneously (in the region of the mammary lymph nodes) with strain b44 e coli bacterin during the last trimester of pregnancy. the calf of each cow was allowed to nurse colostrum naturally after birth. cows vaccinated by either route of administration were capable of providing increased resistance to their ...1979393149
endotoxin enhancement of plasma cell tumor development in mice given injections of mineral oil.bacterial endotoxins administered to balb/c mice given i.p. mineral oil cause an increased incidence of plasma cell tumors, compared with mice given either oil or antigens alone, or oil plus antigen other than endotoxin. endotoxin in ng doses was more effective than in mug doses.1976773532
enzymatic multiplication of a chemically synthesized dna fragment.a synthetic dna fragment of 19 residues was enlarged by the enzymatic addition of deoxyadenylate residues to its 3'-end with calf thymus terminal deoxynucleotidyl transferase. the 3'-terminus of this elongated dna strand was blocked with 2', 3'-dideoxyadenylate to prevent hydrolysis by the 3'-exonuclease function of e. coli dna polymerase i. this elongated and 3'-blocked fragment was annealed to an oligomeric primer and used as a template for the synthesis of a complementary copy of the syntheti ...19751093143
[false-positive results obtained on examining slaughtered animals for the presence of antibiotic residues (author's transl)].as part of the examination of emergency-slaughtered animals for the presence of antibiotic residues, studies were done to see whether false-positive results would be obtained when the sarcina lutea kidney test and bacillus subtilis bga test were performed. when the s. lutea kidney test was positive in cattle, calves and swine, penicillin was invariably found to be present in those animals, the histories of which showed that they had not been given antibiotics. a syringe and an injected fluid con ...1975809859
herd studies on coliform mastitis.escherichia coli, enterobacter aerogenes, and klebsiella pneumoniae were responsible for 63, 10, and 11 percent, respectively, of 158 coliform organisms recovered from mastitis cases in 8 california herds. the severity and nature of the coliform mastitis problem were found to vary greatly among herds but were characteristic for each of 4 herds studied in detail.1975804464
[problems of resistance (author's transl)].the results of sensitivity tests performed during the period from 1970 up to 1973 inclusive are compared with those obtained in pervious years. this showed that resistance to penicillin had increased in staphylococci causing bovine mastitis. during each single year, however, there was a decrease. s. typhimurium isolated from cattle showed increased resistance to chloramphenicol, neomycin and ampicillin; s. dublin showed an increase in resistance to chloramphenicol. e. coli isolated from calves w ...19751096359
[etiology of dairy cows mastitis in slovakia in the years 1972-1974].in the period from 1972 to 1974, veterinary institutes in slovakia performed bacteriological examinations in 178,853 milk samples coming from 72,454 dairy cows. on an annual average, the number of examined samples were higher by 61% than in 1967-1971. germs responsible for the inflammation of the mammary gland were found in the milk of 22.32% of the dairy cows. the following bacterial germs were represented: streptococcus agalactiae -- 15.77%, staphylococcus aureus -- 4.19%, other streptococci ...1975813355
diverse effects of bursectomy on humoral immune responses in the chicken.chickens bursectomized hormonally or surgically at various ages in embryonic to postembryonic lives were immunized with a mixture of antigens, and the antibodies produced titrated. immune responses to salmonella pullorum (sp), brucella abortus (ba). staphylococcus aureus (staph) and ovalbumin (oa) were more markedly suppressed by the bursal deprivation than those to heterogenous erythrocytes, viruses and such bacteria as pasteurella multocida (pm) and escherichia coli b. the immune response to b ...19751187514
bactericidal and haemolytic activity of complement in bovine colostrum and serum: effect of proteolytic enzymes and ethylene glycol tetraacetic acid (egta).bovine colostral whey (cw) possessed heat-labile bactericidal activity against an enteropathogenic serum-susceptible strain of escherichia coli. activity was readily destroyed by trypsin or rat pancreatic juice, and less readily by chymotrypsin. loss of activity due to trypsin, but not by chymotrypsin, could be prevented by addition of excess bovine colostral trypsin inhibitor. a second enteropathogenic strain of e. coli was killed by cw only if exogenous complement was added. this activity was ...1975813560
reversibility of partial denaturation of dna.the hypochromicity recovery of a partially denatured dna sample when salt concentration is suddenly increased at an intermediate stage of the transition, is studied. the results of csc1 gradient analysis, polyethylenglycol/dextran partition analysis, and the behaviour in a new thermal transition, support the view that the process is an intramolecular double chain renaturation as that induced by cooling. the degree of denaturation irreversibility is dependent on the size of dna segments between t ...1976825148
[infective situation in a cow barn contaminated with klebsiella mastitis].the infection situation in a four-row cow-house for 153 animals with a frequent occurrence of klebsiella mastitis was subject to a detailed analysis. the following results were obtained after two collections of blood and udder-quarter milk samples examined by the test-tube agglutination, gel precipitation, and bacteriological diagnosis methods: 1. streptococcus agalactiae was isolated from milk samples 28 and 31 times, pseudomonas aeruginosa 15 and 19 times, staphylococcus arueus 16 and 19 times ...1976828991
[etiology of mastitidos in dairy cows in slovakia during 1975].in 1975, in the veterinary institutes in slovakia bacteriological examinations of 54824 samples of milk coming from 28737 dairy cows were performed. bacterial germs responsible for the inflammation of the mammary gland were found in the milk of 18.91% of cows. these were: streptococcus agalactiae (in 13.93% of cows), staphylococcus aureus (2.86%), other streptococci (1.32%), e. coli (0.13%), klebsiella sp. (0.13%), corynebacterium pyogenes (0.15%), other bacterial germs (0.39%). streptococci and ...1976828997
quantitation of amanitins in amanita verna with calf thymus rna polymerase b.a procedure utilizing the specific inhibition of calf thymus dna-directed rna polymerase b has been applied to the quantitation of amanitins. this procedure has permitted the accurate quantitation of alpha-amanitin in amounts as low as 0.05 nanogram, a sensitivity 2000-fold greater than chemical detection methods used following tlc. analysis of extracts of specimens of amanita verna identified by morphological criteria has demonstrated that while toxin concentration is variable, some specimens ...19751094215
some effects of calcium and magnesium ions on the activity of bovine pancreatic deoxyribonuclease a.bovine pancreatic deoxyribonuclease requires divalent metal cations for hydrolysis of dna. the effects of calcium and magnesium, alone and combined, on the rate and kinetics of the reaction were examined. divalent metal salts of dna were used as substrates. the ratio of either ca-2+ or mg-2+ to dna-p in these salts was 1:2. the mg-2+ salt of dna was found to have sufficient mg-2+ for optimal dnaase activity. addition of mgcl-2 to a large excess of mg-2+ over dna-p had no effect on the rate. km f ...19751095074
antibodies to the triplet codons aaa, aac, and aug: reactions with nucleic acids.antibodies specific for the trinucleotide codons aaa, aug, and aac were examined for their reactions with nucleic acids. anti-aug and anti-aac precipitated denatured dna. anti-aaa did not, and moreover, the binding of a tritiated aaa derivative to anti-aaa was not inhibited by denatured dna. radioligand-binding studies showed that anti-aaa was highly specific for the triplet sequence, some cross-reactions occurring with di-a and tetra-a but little with a and poly(a). the anti-codons did not prec ...1976774989
defective mononuclear leukocyte chemotaxis in the chediak-higashi syndrome of humans, mink, and cattle.chemotaxis of mononuclear leukocytes from humans, mink, and cattle was evaluated in vitro using a morphologic boyden chamber technique and a new 51-cr-labeled mononuclear radioassay with a double micropore filter system. significantly decreased mononuclear leukocyte chemotactic response were noted when human, mink, or cattle chediak-higashi cells were tested using autologous serum or endotoxin-activated autolotous serum. a similar chediak-higashi mononuclear leukocyte defect was noted in humans ...19751092386
[methionyl-trna synthetase from wheat embryo: dissociation into subunits (author's transl)].wheat -embryo methionyl-trna synthetase is a dimeric protein of beta2 structure. when highly diluted, it loses the capacity to catalyze atp-[32p]ppi exchange and to aminoacylate trnamet: at low enzymatic concentrations the rates of formation of[32p]atp and [14c]methionyl-trnamet are lower than those predicatedby extrapolating the rates determined at higher enzyme concentrations. the difference between observed and expected rates becomes greater with decreasing enzyme concentration. filtration of ...1977849749
cloning of calf thymus satellite i dna in escherichia coli.the 1400 base pair repeat produced by digestion of calf satellite i dna (phi = 1.714 g/cm3) with ecori, was cloned in e. coli. the hybrid plasmid (pgm 214) which contains the cole1-ap vector (psf 2124) and the 1400 base pair fragment replicates stably in e. coli and can be amplified by chloramphenicol treatment. no clone was found in which more than one "repeat unit" of the satellite i dna was present in the chimaera plasmid. digestion of the original satellite i and the plasmid pgm 214 with r-s ...1976796669
indirect consequences of low-level use of antimicrobial agents in animal feeds.antibiotics may be classified as "therapeutic" or "feed" depending on their use for treatment of disease or for promotion of growth in animals. the mechanism of growth promotion is largely unknown, but it has been shown that the specific feed additive causes defined lesions in the cell wall of escherichia coli. this effect may sensitize the bacteria to the action of therapeutic drugs. damage to the bacterial cell wall may also cause the bacteria to be more susceptible to the body defense mechani ...19751090454
inhibition of escherichia coli by bovine colostrum and post-colostral milk. i. complement-mediated bactericidal activity of antibodies to a serum susceptible strain of e. coli of the serotype o 111.bovine colostral whey diulted in unheated bovine milk or in kolmer saline containing 5 per cent pre-colostral calf serum was bactericidal for escherichia coli nctc 9703 (serotype o 111). whey diluted in saline without pre-colostral calf serum was inactive. bactericidal activity was abolished by heating at 56 degrees for 30 minutes or by pre-incubating with n-acetyl-l-tyrosine ethylester, indicating that complement present in milk or pre-colostral calf serum was involved in the bactericidal activ ...19751090521
coliform contaminated bedding and new infections.ten holstein cows were bedded on fresh, uncured sawdust seeded with coliform broth culture. escherichia coli concentrations were maintained at 10(6) colony-forming units/g for the 4-wk experimental period. ten control cows were bedded with dry shavings. the elevated bacterial contamination caused an increase in contamination of teat ends; however, no new coliform infections occurred.1976795819
[artificial intranasal bacterial invasion in the newborn calf. 1. quantitative assessment of nasal secretion for certain groups of bacteria].a technique has been developed for quantitative assessment of nasal secretion for the presence of specified groups of bacteria, as a contribution to microbiological treatment of the problem of artificial intranasal bacterial invasion in newborn and nursed calf. some 10(6) to 10(7) bacteria were recorded from each gram of nasal secretion in calves exposed to natural bacterial invasion. micrococci and green diplococci were very rare, with only 10(3) to 10(4) or hardly up to 10(5) bacteria per gram ...1976786200
[artificial intranasal bacterial invasion in the newborn calf. 2. artificial bacterial invasion using gram-positive and gram-negative strains].a micrococcal and a diplocaccal strain isolated from the nasal space of a clinically intact nursed calf were used for artificial bacterial invasion in the first phase of the experiment. application of bacterial suspension prepared from those strains had no effect upon the rise of coli counts in the nasal secretion of nursed calves during their first days of age nor upon the morbidity or mortality of all 677 test animals in comparison to 665 controls. therefore, an avirulent e.-coli strain was us ...1976786201
[bacteriocinogeny in yersinia enterocolitica].bacteriocinogeny was found in 19.8 per cent of y. enterocolitica strains tested. it was designated by the authors as enterocoliticacinogeny and the substance produced by the pathogen was named enterocoliticacine. bacteriocinogeny was found among the collection strains isolated in the south primorye and not among the strains isolated abroad. some cultures of y. enterocolitica isolated abroad and in the south primorye were used as indicator strains for revealing enterocoliticacinogeny. enterocolit ...19751091204
a case-control study of selected pathogens including verocytotoxigenic escherichia coli in calf diarrhea on an ontario veal farm.a case-control study of diarrheal disease in veal calves was conducted over a three month period on a single large veal farm in southern ontario. one hundred diarrheic calves (cases) were identified by visual examination of their feces. each case was matched to two nondiarrhetic controls from the same room on the same day, and a fecal sample was obtained from each animal. fecal consistency of cases and controls was observed daily for one week following sample collection. control calves which dev ...19921330276
secondary-structure predictions of calcium-binding proteins.the known tertiary structure of carp muscle parvalbumin is consistent with an "ef-hand" architecture (helix-loop-helix) for each calcium-ion binding site. primary-sequence alignments have indicated four ef hands in rabbit skeletal muscle troponin c and in rabbit myosin alkali light chains. five secondary-structure prediction methods, based on amino acid sequence only, have been fully computerized and used to calculate joint prediction histograms for several calcium-binding proteins. the joint hi ...1977836806
the effects of overloading in density-gradient centrifugation.the effects of overloading of the sample zone in density gradient centrifugation have been studied by use of a three-component shelf-lavered sample in which the total protein concentration was increased by addition of different amounts of albumin. it is found that overloading of the gradient gives rise to particle movements which are not predictable from the svedberg equation. the two typical effects of overloading are dislocation of the zone mass centres and changes in the zone shapes. it is fo ...19751097246
recombinant polypeptide from the gp48 region of the bovine viral diarrhea virus (bvdv) detects serum antibodies in vaccinated and infected cattle.to characterize the immune response of cattle to bovine viral diarrhea virus (bvdv) glycoprotein gp48, we have produced a large amount of recombinant glutathione-s-transferase-gp48 (gst-gp48) fusion protein in escherichia coli. antibodies to gp48 were present in cattle vaccinated with killed or modified-live virus vaccination, or following natural infection. these results were in agreement with results of serum neutralization (sn) test which detected gp53 of bvdv.19921333674
tissue distribution and residues of beta-lactam antibiotics in normal dairy cows.tissue residues and concentrations of benzylpenicillin, cloxacillin, ampicillin, amoxycillin, cephapirin, and cephacetrile were determined in normal dairy cows after parenteral administration of several forms of these drugs. assay methods included the sarcina lutea kidney test of van schothorst, the bacillus subtilis bga tests at ph 6.0 and 8.0, the escherichia coli test and a sarcina lutea test performed at ph 8.0 of the agar, and specific quantitative assay methods. the e. coli test method dem ...1977918925
[indices of bacteriological purity of milk obtained in cowsheds during mastitis controla1]. 1976797599
hematology of the neonatal calf. ii. response associated with acute enteric infections, gram-negative septicemia, and experimental endotoxemia.the hematological responses of neonatal calves with acute enteric infections were compared to the responses of calves with septicemia and experimentally induced endotoxemia. the mean hematocrit of septicemic calves (45.0% +/- 7.8) was similar to that of calves with primary enteric infections (45.3% +/- 7.0) but the total plasma protein concentration of septicemic calves (5.8g/100 ml +/- 0.69) was significantly lower than that of calves with primary enteric infections (8.6 g/100 ml +/- 1.5). the ...19751104259
enzymatic arginylation of beta-melanocyte-stimulating hormone and of angiotensin ii.porcine beta-melanocyte-stimulating hormone and angiotensin ii were examined as acceptors in the reaction catalyzed by arginyl-trna-protein transferase. both inhibited enzymatic transfer of [14c]arginine from trna to bovine albumin. inhibition was competitive with albumin and the k-i values were, respectively, 15 and 0.8 mum. the expected arginylated compounds were isolated and characterized. beta-melanocyte-stimulating hormone and its arginylated product had identical activities in the frog epi ...19751091639
the effects of organic solvents on escherichia coli dna polymerase iii.the polymerizing ability of escherichia coli dna polymerase iii is enhanced by a variety of water-miscible organic solvents of which dimethyl sulfoxide at 17% (v/v) is the most effective tested. the extent of stimulation depends on the organic solvent used and its concentration, but shows no obvious correlation with the chemical structure of the solvent or its dielectric constant. kinetic studies indicate that the mechanism of stimulation is complex.19751098695
effects of thermostable escherichia coli enterotoxin peptide on the isolated rat kidney.in order to compare the function of sodium transport between the intestine and renal tubule, we studied the effect of thermostable e. coli enterotoxin on rat kidneys. isolated kidneys from adult male hooded rats weighing 240-335 g were perfused with krebs-henseleit solution containing 60 mg/ml dialyzed bovine serum albumin. the effects of e. coli enterotoxin (sta; molecular weight approximately 2000; 18 amino acids with three disulfide bonds) were studied on glomerular filtration rate (gfr), net ...19921342238
[sodium thiocyanate as a protective agent in intensive calf fattening. brief report].daily administration of sodium thiocyanate at 750 mg a calf for the first three weeks in the fattening stalls reduced the occurrence of illness by 60%. this protective effect seemed to persist during the following weeks without additional treatment. addition of the thiocyanate to the food may be beneficial through a nutritive effect.19751106349
distribution of r plasmids among the o-antigen types of escherichia coli isolated from human and animal sources.the o-antigen types of 600 independently isolated escherichia coli strains from human feces have been determined, and the types have been related to the antibiotic resistance patterns of the strains. the relative abundance of each o-antigen type differed in the susceptible and resistant series of strains. the majority (86%) of the resistant strains carried r plasmids. resistant e. coli (20.3%) were found associated with o-antigen types 8, 9 and 101, whereas the susceptible strains covered a wide ...19751101815
studies on the binding of 5,5-diphenyl-hydantoin to nucleic acids in vitro and to rat brain subcellular fractions in vitro and in vivo.the binding of 5,5-diphenylhydantoin (dph) to nucleic acids (bovine brain rna, rat liver ribosomal and trna, torula utilis rna, and calf thymus and escherichia coli dna was studied using ultraviolet spectroscopy, gel chromatography and thermal transition profiles. within the sensitivity of these methods, it was found that there is essentially little or no interaction between dph and nucleic acids in vitro as has been reported previously. little, if any evidence of dph intercalation with dna was ...19761255490
expression of the phosphorylase kinase gamma subunit catalytic domain in escherichia coli.the catalytic subunit of phosphorylase b kinase (gamma) and an engineered truncated form (gamma-trc, residues 1-297) have been expressed in escherichia coli. the truncated protein included the entire catalytic domain as defined by sequence alignment with other protein kinases but lacked the putative calmodulin binding domain. full-length protein was produced in insoluble aggregates. some activity was regenerated by solubilization in urea and dilution into renaturating buffer but the activity was ...19921287663
escherichia coli f0f1-atpase. residues involved in catalysis and coupling.the molecular biological approach has provided important information toward understanding the complexities of the f0f1 atpase. this article focuses on our recent results on the atpase catalytic site contained in the beta subunit and the role of the gamma subunit in regulation of proton transport. we used a combination of affinity labeling and mutagenesis to locate several residues of the alpha and beta subunits in the catalytic site. adenosine triphosphopyridoxal (ap3-pl) labeled beta lys-155, b ...19921288330
deoxyribonucleic acid-cytosine methylation by host- and plasmid-controlled enzymes.deoxyribonucleic acid (dna)-cytosine methylation specified by the wild-type escherichia coli k 12 mec+ gene and by the n-3 drug resistance (r) factor was studied in vivo and in vitro. phage lambda and fd were propagated in the presence of l-[methyl-3h]methionine in various host bacteria. the in vivo labeled dna was isolated from purified phage and depurinated by formic acid-diphenylamine treatment. the resulting pyrimidine oligonucleotide tracts were separated according to size and base composit ...19751091619
chaperonins groel and groes promote assembly of heterotetramers (alpha 2 beta 2) of mammalian mitochondrial branched-chain alpha-keto acid decarboxylase in escherichia coli.we have investigated the possible role of chaperonins groel and groes in the folding and assembly of heterotetramers (alpha 2 beta 2) of mammalian mitochondrial branched-chain alpha-keto acid decarboxylase (e1) in escherichia coli. the mature e1 alpha subunit fused to maltose-binding protein (mbp) was coexpressed with mature e1 beta on the same vector in es- and el- mutant strains. only small or trace amounts of active e1 component were obtained. cotransformation of the es- mutant host with a se ...19921352285
molecular and immunological characterization of adp-ribosylarginine hydrolases.mono-adp-ribosylation is a reversible modification of proteins with nad:arginine adp-ribosyltransferases and adp-ribosylarginine hydrolases catalyzing the forward and reverse reactions, respectively. hydrolase activities were present in a variety of animal species, with the highest specific activities found in rat and mouse brain, spleen, and testis. rat and mouse hydrolases were dithiothreitol- and mg(2+)-dependent, whereas the bovine and guinea pig enzymes were dithiothreitol-independent. a ra ...19921375222
molecular cloning and functional expression of cdna encoding a mammalian inorganic pyrophosphatase.extracts of soluble proteins from bovine retina contain multiple species of inorganic pyrophosphatase (ppase) that can be resolved by hydroxylapatite or ion exchange chromatography. we have purified one of these isoforms by a combination of chromatography and electrophoresis under denaturing conditions and have partially sequenced four peptides generated from it by cnbr digestion. this sequence information was used to clone ppase cdna from a retinal cdna library. of five cdna inserts, three were ...19921339444
mammalian mitochondrial chaperonin 60 functions as a single toroidal ring.chaperonins are thought to participate in the process of protein folding in bacteria and in eukaryotic mitochondria and chloroplasts. while some chaperonins are relatively well characterized, the structures of the mammalian chaperonins are unknown. we have expressed a mammalian mitochondrial chaperonin 60 in escherichia coli and purified the recombinant protein to homogeneity. structural and biochemical analyses of this protein establish a single toroidal structure of seven subunits, in contrast ...19921346131
coob is required for assembly but not transport of cs1 pilin.cs1 pili are filamentous proteinaceous appendages found on many enterotoxigenic escherichia coli (etec) strains isolated from human diarrhoeal disease. they are thought to effect colonization of the upper intestine by facilitating binding to human ileal epithelial cells. we have identified a gene, coob, which lies directly upstream of cooa, the gene that encodes the major structural cs1 protein. when translated in vitro, the protein product of coob migrates in sodium dodecyl sulphate/polyacrylam ...19921348100
modification of resistance of mice to naegleria fowleri infections.naegleria fowleri, which produces a fatal meningoencephalitis in humans, is also able to produce a progressive and fatal disease in mice. the course of the disease in dub/icr mice is dependent upon the infecting dose of organisms, whether administered intraperitoneally (i.p.) or intravenously (i.v.). all of the mice receiving 10(7) trophozoites/mouse i.v. or 4.85 x 10(7) trophozoites/mouse i.p. were killed within 10 days. escherichia coli o26:b6 lipopolysaccharide, administered at a dose of 1 mg ...19761270145
serogroups of escherichia coli strains producing cytotoxic necrotizing factors cnf1 and cnf2.the serogroups of 396 necrotizing escherichia coli of human and bovine origin isolated in spain between 1979 and 1991 have been determined. the 270 cytotoxic necrotizing factor strains belonged to 22 different o serogroups; however, 84% (226 of 270) were of one of seven serogroups (o2, o4, o6, o14, o22, o75 and o83). although necrotizing e. coli producing cytotoxic necrotizing factor 2 belonged to 28 different serogroups, only six of them (o1, o3, o15, o55, o88 and o123) accounted for 60% (76 of ...19921398031
recombinant hiv-1 nucleocapsid protein p15 produced as a fusion protein with glutathione s-transferase in escherichia coli mediates dimerization and enhances reverse transcription of retroviral rna.human immunodeficiency virus 1 (hiv-1) nucleocapsid protein p15 was produced as a fusion protein with glutathione s-transferase (gst) in escherichia coli. rapid purification of gst::p15 in an active form by one-step glutathione-agarose chromatography was accomplished in the presence of an antioxidant. recombinant p15 fused to gst was shown to stimulate the dimerization of viral rna. hiv-1 reverse transcriptase-catalyzed in vitro synthesis of minus-strand cdna from synthetic human trna(lys3uuu) a ...19921280240
identification of inducible calmodulin-dependent nitric oxide synthase in the liver of rats.a calmodulin-dependent nitric oxide synthase was significantly induced in the liver of rats treated intravenously with heat-killed propionibacterium acnes and 5 days later with escherichia coli lipopolysaccharide. the apparent calmodulin-dependent and -independent isozymes were separated by mono q column chromatography after their partial purification by 2',5'-adp-agarose affinity chromatography. both enzymes had a molecular weight of 125,000 as determined by sds-polyacrylamide gel electrophores ...19921281157
renaturation of citrate synthase: influence of denaturant and folding assistants.citrate synthase (cs), which has been denatured in either guanidine hydrochloride (gdnhcl) or urea can be assisted in its renaturation in a variety of ways. the addition of each of the assistants--bovine serum albumin (bsa), oxaloacetate (oaa), and glycerol--promotes renaturation. in combination, the effect of these substances is additive with respect to the yield of folded cs. the report of buchner et al. (buchner, j., schmidt, m., fuchs, m., jaenicke, r., rudolph, r., schmid, f.x., & kiefhaber ...19921363914
susceptibility to antibiotics of escherichia coli strains isolated from diarrhoeic and non-diarrhoeic livestock in trinidad.the sensitivity of strains of escherichia coli isolated from calves, piglets, lambs and kids in trinidad to seven antibiotics was determined. two hundred and sixty-four (91.3%) of 289 strains isolated from diarrhoeic animals and 173 (87.4%) of 198 strains from non-diarrhoeic animals exhibited resistance to one or more antibiotics. the difference was not statistically significant (p > or = 0.05; x2). regardless of health status, isolates from lambs were least resistant (75.0%) and those from pigl ...19921339991
[detection of verotoxin-producing escherichia coli using polymerase chain reaction from dairy cattle].the vero cytotoxin (vt) is responsible for hemorrhagic colitis and hemolytic uremic syndrome. polymerase chain reaction (pcr) was used to detect vt-producing coliform bacteria from dairy cattle. it was found that 39 (33.3%) of the 117 fecal samples examined were recognized with vt genes in bglb enrichment broth by the pcr method (named bglb-pcr). of the vt-positive samples, 31 samples (26.5%) were found to have vt-producing escherichia coli. frequencies of isolation in younger cattle (under 5 mo ...19921293218
the biological interaction of cis- and trans-urocanic acid and dna.the potential for the cis and trans isomers of urocanic acid to produce dna damage was measured by assays for dna binding (32p-postlabeling assay), for induction of dna repair (unscheduled dna synthesis assay) and induction of mutations (salmonella typhimurium and escherichia coli plate-incorporation assays). these assays did not detect any evidence of a direct effect of either isomer of urocanic acid on dna over a wide range of concentrations. these results suggest that neither isomer of urocan ...19921300140
[comparative study of some quaternary ammoniums neutralizing agents. influence of the nature of the bacterial strains used].the neutralising capacity of the anti-bacterial activity of a quaternary ammonium salt, depends on the nature of the bacterial strains used. consequently, the choice of a neutralising agent of the bactericidal activity can only be made following a preliminary study on several bacterial species. out of five products which we tested, we found the tween-lecithin fresh egg mixture alone had satisfactory activity.1975812041
acute coliform mastitis in dairy cows: endotoxin and biochemical changes in plasma and colony-forming units in milk. 19921300679
functional reconstitution of membrane proteins in monolayer liposomes from bipolar lipids of sulfolobus acidocaldarius.membranes of sulfolobus acidocaldarius, an extreme thermophilic archaebacterium, are composed of unusual bipolar lipids. they consist of macrocyclic tetraethers with two polar heads linked by two hydrophobic c40 phytanyl chains which are thought to be arranged as a monolayer in the cytoplasmic membrane. fractionation of a total lipid-extract from s. acidocaldarius yielded a lipid fraction which forms closed and stable unilamellar liposomes in aqueous media. beef heart cytochrome c-oxidase could ...19921309769
ovine pulmonary surfactant induces killing of pasteurella haemolytica, escherichia coli, and klebsiella pneumoniae by normal serum.pulmonary surfactant has been shown to play an increasingly important role in bacterial clearance at the alveolar surface in the lung. this study describes a bactericidal mechanism in which ovine pulmonary surfactant induces killing of pasteurella haemolytica by normal serum. to demonstrate killing, six bacterial species were incubated first with pulmonary surfactant for 60 min at 37 degrees c and then with serum for an additional 60 min at 37 degrees c. p. haemolytica type a1 strains 82-25 and ...19921452351
the stability and functional properties of proteoliposomes mixed with dextran derivatives bearing hydrophobic anchor groups.liposomes composed of escherichia coli phospholipid were coated with polysaccharides bearing hydrophobic palmitoyl anchors. the effect on the stability of liposomes without or with integral membrane proteins was investigated. a high concentration of hydrophobized dextrans protected the liposomes against detergent degradation, decreased the fluidity of the membranes, prevented fusion of the liposomes and enhanced their stability. proteoliposomes containing beef heart cytochrome-c oxidase and the ...19921374644
molecular characterization of cdna encoding for adenylate kinase of rice (oryza sativa l.).two types of genes (adk-a, and adk-b) encoding for adenylate kinase (ak, ec 2.7.4.3.) were isolated from the cdna library constructed from poly(a)+ rna of rice (oryza sativa l.). two cdnas were heterogeneous at 5' and 3' ends of non-coding sequences and had possible polyadenylation signals. one of the genes, adk-a, had 1154 bp sequences encoding 241 amino acid residues, while the other type, adk-b, contained 1085 bp sequences encoding for 243 amino acid residues. homology between adk-a and adk-b ...19921302636
[p26--a calcium binding protein from photoreceptor cells in the bovine retina: primary structure and expression in e. coli].the primary structure of the bovine retinal calcium binding protein p26 has been determined by the parallel analysis of the protein and the corresponding cdna. this protein is identical to recovering and shares 59% homology with visinin, a cone specific calcium binding protein from chicken retina. p26 was expressed in e. coli as a fusion protein and, after purification by affinity chromatography on igg-sepharose 6, cleaved off with enteropeptidase.19921417990
organella-targeted expression of rat liver cytochrome p450c27 in yeast. genetically engineered alteration of mitochondrial p450 into a microsomal form creates a novel functional electron transport chain.a modified rat cytochrome p450c27, whose mitochondrial targeting signal had been replaced by a possible microsomal targeting signal of bovine cytochrome p450c17, was expressed in yeast. the modified p450c27 hemoprotein was correctly localized on yeast microsomes and exhibited the p450c27-dependent monooxygenase activity by addition of bovine adrenodoxin (adx) and nadph-adrenodoxin reductase (adr). considering the previous observation that p450c27 with its own mitochondrial targeting signal was i ...19921322905
structural elements required for the cooperative binding of the herpes simplex virus origin binding protein to oris reside in the n-terminal part of the protein.the origin binding protein (obp) of herpes simplex virus type 1 is required to activate a viral origin of replication in vivo. we have used intact obp as well as a truncated form of the protein expressed in escherichia coli to investigate the protein-protein interactions, as well as the protein-dna interactions involved in the formation of a nucleoprotein complex at a viral origin of replication (oris) in vitro. the salient findings demonstrate that the n-terminal part of obp is required for the ...19921324937
cis proline mutants of ribonuclease a. i. thermal stability.a chemically synthesized gene for ribonuclease a has been expressed in escherichia coli using a t7 expression system (studier, f.w., rosenberg, a.h., dunn, j.j., & dubendorff, j.w., 1990, methods enzymol. 185, 60-89). the expressed protein, which contains an additional n-terminal methionine residue, has physical and catalytic properties close to those of bovine ribonuclease a. the expressed protein accumulates in inclusion bodies and has scrambled disulfide bonds; the native disulfide bonds are ...19921338975
glutathione reductases from a variety of sources are inhibited by physiological levels of glutathione.1. glutathione reductase from human platelets, bovine intestinal mucosa, yeast and e. coli were inhibited in vitro by physiological levels of reduced glutathione with ic50s of 6.61 mm, 2.92 mm, 2.40 mm and 12.11 mm, respectively. 2. a steady-state kinetic examination revealed that glutathione inhibited the nadph oxidation (at constant [glutathione-disulphide]) catalysed by the eucaryotic enzymes uncompetitively, whereas the e. coli enzyme appeared unaffected by glutathione concentrations of up t ...19921478068
cloning, expression, and catalytic mechanism of the low molecular weight phosphotyrosyl protein phosphatase from bovine heart.the first representative of a group of mammalian, low molecular weight phosphotyrosyl protein phosphatases was cloned, sequenced and expressed in escherichia coli. using a 61-mer oligonucleotide probe based on the amino acid sequence of the purified enzyme, several overlapping cdna clones were isolated from a bovine heart cdna library. a full-length clone was obtained consisting of a 27-bp 5' noncoding region, an open reading frame encoding the expected 157 amino acid protein, and an extensive 3 ...19921339287
a specific dna probe which identifies babesia bovis in whole blood.a genomic library of babesia bovis dna from the mexican strain m was constructed in plasmid pun121 and cloned in escherichia coli. several recombinants which hybridized strongly to radioactively labeled b. bovis genomic dna in an in situ screening were selected and further analyzed for those which specifically hybridized to b. bovis dna. it was found that pmu-b1 had the highest sensitivity, detecting 25 pg of purified b. bovis dna, and 300 parasites in 10 microliters of whole infected blood, or ...19921496779
adherence and colonization by bacterial pathogens in explant cultures of bovine mammary tissue.explant cultures of bovine mammary tissue taken from virgin heifers were used to examine adherence, colonization and cytopathogenesis of streptococcus uberis, streptococcus agalactiae, streptococcus dysgalactiae, staphylococcus aureus and escherichia coli in the putative target tissue. none of the five bacteria was able to adhere to healthy ductular epithelium but all showed a marked tropism for exposed connective tissue. s. aureus and e. coli induced a marked cytopathic effect in ductular epith ...19921496817
mip protein of legionella pneumophila exhibits peptidyl-prolyl-cis/trans isomerase (pplase) activity.legionella pneumophila is an intracellular parasite which is able to survive and multiply in human monocytes and alveolar macrophages. the mip (macrophage infectivity potentiator) protein has been shown to be an essential virulence factor. a search of translated nucleic acid data bases has shown that the mip protein from strain wadsworth possesses regions homologous to those found in the fk506-binding proteins (fkbps) of several different eukaryotic organisms. fkbps are able to bind to the immun ...19921379319
mapping of sequential epitopes recognized by monoclonal antibodies on the bovine leukaemia virus external glycoproteins expressed in escherichia coli by means of antipeptide antibodies.a lambda gt11 cdna library prepared from bovine leukaemia virus (blv)-producing ovine cells was screened with a cocktail of anti-blv gp51 monoclonal antibodies (mabs). four recombinant phages with inserts of about 2-5 kbp were isolated. one, lambda blv-gp51-1, was sequenced and shown to encode the c-terminal part of gp51 and all of gp30. this insert was subcloned into pev-vrf1 and expressed in escherichia coli n-4830-1 cells. the blv product and a series of antipeptide antibodies were used to lo ...19921383413
purification and characterization of the blue-green rat phaeochromocytoma (pc12) tyrosine hydroxylase with a dopamine-fe(iii) complex. reversal of the endogenous feedback inhibition by phosphorylation of serine-40.tyrosine hydroxylase (th) was purified from tumours of rat phaeochromocytoma (pc12) cells by a three-step purification procedure giving 30 mg of pure enzyme in 3 days. the enzyme sedimented with an s(eo),w value of 9.2 s and revealed an apparent subunit molecular mass of 62 kda with a minor 60 kda component. two-dimensional gel isoelectric focusing/electrophoresis and tryptic digestion revealed that the heterogeneity could be accounted for by limited proteolysis of the 62 kda component and the p ...19921352446
regulation of intestinal guanylate cyclase by the heat-stable enterotoxin of escherichia coli (sta) and protein kinase c.the heat-stable enterotoxin of escherichia coli (sta) stimulates membrane-bound guanylate cyclase in intestinal epithelium and induces fluid and ion secretion. using the t84 human colon carcinoma cell line as a model, we observed that phorbol esters markedly enhanced sta-stimulated cyclic gmp accumulation in t84 cells (c. s. weikel, c. l. spann, c. p. chambers, j. k. crane, j. linden, and e. l. hewlett, infect. immun. 58:1402-1407, 1990). in this study we document that the phorbol ester treatmen ...19921360449
expression and purification of growth hormone-releasing factor with the aid of dihydrofolate reductase handle.expression of a fusion protein composed of dihydrofolate reductase and a derivative of growth hormone-releasing factor resulted in the formation of inclusion bodies in escherichia coli at 37 degrees c. among various chemicals, such as detergents, protein denaturants, and acetic acid, tested for the ability to dissolve the inclusion bodies, acetic acid, brij-35, deoxycholic acid sodium salts, guanidine-hcl, and urea showed a strong solubilizing effect without damaging the dhfr activity. acetic ac ...19921331037
characterization of the human calmodulin-like protein expressed in escherichia coli.the protein-coding region of an intronless human calmodulin-like gene [koller, m., & strehler, e. e. (1988) febs lett. 239, 121-128] has been inserted into a pkk233-2 expression vector, and the 148-residue, m(r) = 16,800 human protein was purified to apparent homogeneity by phenyl-sepharose affinity chromatography from cultures of escherichia coli jm105 transformed with the recombinant vector. several milligrams of the purified protein were obtained from 1 l of bacterial culture. a number of pro ...19921334432
equilibrium, kinetic, and footprinting studies of the tus-ter protein-dna interaction.arrest of dna replication in the terminus region of the escherichia coli chromosome is mediated by protein-dna complexes composed of the tus protein and 23 base pair sequences generically called ter sites. we have characterized the in vitro binding of purified tus protein to a 37-base pair oligodeoxyribonucleotide containing the terb sequence. the measured equilibrium binding constant (kd) for the chromosomal terb site in kg buffer (50 mm tris-cl, 150 mm potassium glutamate, 25 degrees c, ph 7.5 ...19921313800
effect of intrauterine bacterial infusions and subsequent endometritis on prostaglandin f2 alpha metabolite concentrations in postpartum beef cows.multiparous angus and crossbred angus cows were used to determine the effect of induced endometritis on plasma concentrations of 13,14-dihydro-15-keto-prostaglandin f2 alpha (pgfm) and progesterone (p4) and on duration of the estrous cycle of treatment. beginning on the day of calving (d 0), blood samples were collected on alternate days. on three consecutive days, ranging from d 8 to 14 of the first postpartum estrous cycle, uterine horns were inoculated transcervically with either 3 x 10(9) co ...19921429292
function of the post-translationally modified c-terminal region of rho p21.rhoa p21, a ras p21-like small gtp-binding protein, purified from bovine aortic smooth muscle is similarly modified at its c-terminal region as described for ras p21s. in this study, i examined the role of the post-translational modifications of the c-terminal region of rhoa p21 by comparing bovine rhoa p21 with bacterially-produced rhoa p21 because the bacterial protein was not modified. bovine rhoa p21 bound to plasma membranes, but bacterial rhoa p21 did not. both the stimulatory and inhibito ...19921518273
molecular cloning of a cdna encoding chicken t-protein of the glycine cleavage system and expression of the functional protein in escherichia coli. effect of mrna secondary structure in the translational initiation region on expression.dna clones encoding chicken t-protein of the glycine cleavage system were isolated from chicken liver lambda gt10 cdna libraries. three overlapping clones provided an open reading frame of 1176 nucleotides that predicts a polypeptide of 392 amino acids (m(r) 42,056) comprised of a 16-residue mitochondrial targeting sequence and a 376-residue mature protein (m(r) 40,292). the amino acid sequence predicted for the mature protein showed 67% identity with that of bovine t-protein. a cdna encoding ma ...19921526969
in vitro isoprenylation and membrane association of mouse rod photoreceptor cgmp phosphodiesterase alpha and beta subunits expressed in bacteria.we investigated the specificity of caax box-related isoprenylation of rod photoreceptor cgmp phosphodiesterase (pde) subunits expressed in bacteria and the consequences of this modification on rod disk membrane association. full-length cdna sequences of the alpha and beta subunits of mouse pde, inserted into bacterial pet expression vectors, were overexpressed as fusion proteins containing 28 (bmp-alpha) and 26 (bmp-beta) additional amino acid residues at their n termini. both fusion proteins we ...19921314827
molecular cloning, stage-specific expression and cellular distribution of a putative protein kinase from plasmodium falciparum.a putative protein kinase gene (pfpk2) has been isolated from the human parasite plasmodium falciparum by using a mixed oligonucleotide pool which corresponds to a highly conserved region of serine/threonine protein kinases. the complete nucleotide sequence of 5 kb suggests the existence of a second transcriptional unit besides that of the pfpk2 gene, separated by a highly (a+t)-rich region and transcribed in a different orientation. no intron sequence exists in pfpk2. the predicted amino acid s ...19921378403
production and characterization of recombinant insulin-like growth factor-i (igf-i) and potent analogues of igf-i, with gly or arg substituted for glu3, following their expression in escherichia coli as fusion proteins.the development of an efficient expression system for insulin-like growth factor-i (igf-i) in escherichia coli as a fusion protein is described. the fusion protein consists of an n-terminal extension made up of the first 46 amino acids of methionyl porcine gh ([met1]-pgh) followed by the dipeptide val-asn. the latter two residues provide a unique hydroxylamine-sensitive link between [met1]-pgh(1-46) and the n-terminal gly of igf-i. downstream processing of the fusion proteins involved isolation ...19921311930
[virulence factors in strains of escherichia coli isolated in urinary tract infections].in 21 strains of e. coli isolated from patients with cystitis and asymptomatic bacteriuria the authors assessed the group, mannososensitive and mannoresistant agglutination of human, bovine, chick, guinea pig, sheep and pig erythrocytes, the production of haemolysis, colicins, aerobactin, the capacity of strains to induce oedema on mouse paws, the lethal effect in mice, the resistance to tetracycline, streptomycin, chloramphenicol, kanamycin, ampicillin and sulfamethoxidine, the transmission of ...19921464082
cell selection strategies for making antibodies from variable gene libraries: trapping the memory pool.the b cells of immunized animals can be used as a source of variable region (v) gene libraries. such libraries offer a way of making antibodies directly in bacteria: rearranged v genes are amplified using the polymerase chain reaction, cloned and expressed as soluble fragments in bacteria, and then screened for antigen binding. here we have used a model system to investigate antigen-selected b cells as a source of v gene libraries. mice were immunized with (4-hydroxyl-3-nitrophenyl)acetyl (np)-c ...19921547829
the economic implications of bioengineered mastitis control.this paper estimates the cost of mastitis for the new york dairy sector. the average cost is found to be $125 per cow from reduced milk production, treatment, and increased culling. at the 1988 cow inventory, this translates to approximately $100 million annually for the entire dairy farm sector. when quality and production losses for the processing sector are added, the cost to the new york industry alone is nearly $150 million annually. two promising new treatments, a bacteriocin and a vaccine ...19921560148
the heat-shock protein clpb in escherichia coli is a protein-activated atpase.the clpb gene in escherichia coli encodes a heat-shock protein that is a close homolog of the clpa gene product. the latter is the atpase subunit of the multimeric atp-dependent protease ti (clp) in e. coli, which also contains the 21-kda proteolytic subunit (clpp). the clpb gene product has been purified to near homogeneity by deae-sepharose and heparin-agarose column chromatographies. the purified clpb consists of a major 93-kda protein and a minor 79-kda polypeptide as analyzed by polyacrylam ...19921400361
antibacterial effect of bovine milk antibody against escherichia coli in a mouse indigenous infection model.a skim-milk fraction and a whey-protein concentrate (wpc) fraction were prepared from the cows that had been immunized with e. coli isolated from the mouse intestine. the antibacterial effect of these fractions against e. coli was examined. they contained antibody with a high affinity for e. coli strain 48, a representative strain in the mouse intestine, which is composed of a large amount of igg and smaller amounts of iga and igm. although these fractions showed no bactericidal or bacteriostati ...19921406460
a cloned dna probe for cowdria ruminantium hybridizes with eight heartwater strains and detects infected sheep.the dna probe pcs20, which was cloned from the dna of the crystal springs heartwater strain from zimbabwe, cross-reacted with dnas of heartwater strains from all endemic areas, including four heartwater strains from zimbabwe, two strains from south africa, one strain from nigeria, and the gardel strain from the caribbean island of guadeloupe. by nucleic acid hybridization, the pcs20 dna probe detected cowdria ruminantium dna in all dna preparations made from plasma samples from infected sheep be ...19921572987
[isolation of vero-cytotoxin-producing escherichia coli from cattle and serotyping and toxin-typing of the isolated strains].two hundred and sixty-six piglets with diarrhea (from 4 farms), 73 healthy pregnant pig (from 2 farms), 27 calves with diarrhea (from 9 farms) and 47 healthy milk cows (from 1 farm) were examined for vero-cytotoxin-producing escherichia coli (vtec), and 52, 11, 15 and 67 strains of vtec were isolated from 17 piglets, 11 pregnant pigs, 6 calves and 23 milk cows, respectively. all vtec strains from the piglets produced only vt2vp, while the strains from the healthy pigs did not produce vt2vp, but ...19921431372
adaptation of two commercially available dna probes for the detection of e. coli and staphylococcus aureus to selected fields of dairy hygiene--an exemplary study.the application of two commercially available colorimetric dna hybridization tests (gene-trak e. coli and staphylococcus aureus) to selected aspects of dairy hygiene was investigated. bacterial isolates of different origin, naturally contaminated cheese varieties, nonfat dry milk, milk concentrates, artificially contaminated milk and raw milks from udder quarters were examined. based on the observation that the sensitivity of the e. coli dna probe was comparable to that of the beta-d-glucuronida ...19921575881
the sequence of the flavoprotein subunit of bovine heart succinate dehydrogenase.the cdna sequence of the flavoprotein subunit of bovine heart succinate dehydrogenase is reported. this is the first complete eukaryotic sequence of the flavoprotein subunit to be characterized, and it encodes a 665-amino acid protein that consists of a presequence and a 621-residue mature protein. the deduced bovine sequence shows homology to the corresponding peptides of prokaryotic succinate dehydrogenase and the related fumarate reductases; in particular, there is good overall homology (48%) ...19921375942
identification of the bactericidal domain of lactoferrin.we report the existence of a previously unknown antimicrobial domain near the n-terminus of lactoferrin in a region distinct from its iron-binding sites. a single active peptide representing this domain was isolated following gastric pepsin cleavage of human lactoferrin, and bovine lactoferrin, and sequenced by automated edman degradation. the antimicrobial sequence was found to consist mainly of a loop of 18 amino acid residues formed by a disulfide bond between cysteine residues 20 and 37 of h ...19921599934
identification and expression of a fasciola hepatica gene encoding a gut antigen protein bearing repetitive sequences.a fasciola hepatica cdna clone of about 2 kb was isolated from an expression library by immunological screening using blood serum from an experimentally infected calf. the cdna clone hybridised to a rna of about 3 kb in a northern blot experiment. the nucleotide sequence of the cdna revealed the presence of an open reading frame of 1636 bp which encoded 24 tandemly arranged 20-amino acid-long repeats, followed by 65 non-repeated residues preceding the stop codon. this antigen was expressed in es ...19921435867
protein phosphatase 2a is a specific protamine-kinase-inactivating phosphatase.purified preparations of a protamine protein kinase from bovine kidney cytosol [damuni, amick & sneed (1989) j. biol. chem. 264, 6412-6416] were inactivated after incubation with near-homogeneous preparations of protein phosphatase 2a1 and protein phosphatase 2a2. these protein phosphatase 2a-mediated inactivations of the protamine kinase were unaffected by highly purified preparations of inhibitor 2, but were prevented when the incubations were performed in the presence of 100 nm microcystin-lr ...19921332680
polymerase chain reaction for detection of verocytotoxigenic escherichia coli isolated from animal and food sources.animals and their by-products have been implicated as important sources of verocytotoxigenic escherichia coli (vtec) associated with disease in humans. vtec comprise a wide range of serotypes and produce a variety of closely related verocytotoxins (vt). a pair of oligonucleotide primers, targeting conserved sequences found in vt1, vt2 and vte genes, was used to develop a polymerase chain reaction (pcr) procedure to detect all types of vtec. supernatants of boiled broth cultures of vtec (223 stra ...19921513344
susceptibility of escherichia coli isolated from intramammary infections to phagocytosis by bovine neutrophils.thirteen escherichia coli isolated from naturally occurring imi were tested for susceptibility to phagocytosis by bovine blood neutrophils. isolates were opsonized in pooled serum collected from nine healthy lactating cows. bacteria isolated from imi first diagnosed within 3 d after calving were more resistant to phagocytosis than were isolates from imi originating during either the first half of the dry period or later during lactation. duration of the imi was negatively correlated with both ph ...19921474201
high-level expression of functional human cytochrome p450 1a2 in escherichia coli.enzymatically active human cytochrome p450 1a2 was expressed in escherichia coli utilizing the pcwori+ vector containing a modified cdna. the coding sequence for the nh2-terminal region of the protein was modified by the alignment and substitution of a 27 bp segment from a modified bovine p450 17a1 cdna onto the 5' end of the open reading frame of p450 1a2 at amino acid 21. the expressed chimeric p450 was produced at a high level in a functionally intact form, as assayed by the formation in vivo ...19921537466
genetic control of resistance to enterotoxigenic escherichia coli in infant mice.dba/2 and cba infant mice orally challenged with bovine enterotoxigenic escherichia coli (etec) strain b80 presented resistance and susceptibility respectively, as measured by mortality rates 6 days after inoculation. serum antibodies agglutinating etec strain b80 had very low titers in both mouse strains. mendelian analysis of resistance on f1 and on segregating back-crosses showed that resistance is genetic and dominant. dominance may be explained either by a mixed control with an overdominant ...19921453928
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