Publications
| Title | Abstract | Year Filter | PMID(sorted ascending) Filter |
|---|
| rotavirus infections in calves in dairy herds. | neonatal calf diarrhoea was studied in 115 calves of one dairy herd from january 1976 to june 1977. two syndromes could be distinguished: a mild and short lasting 'early diarrhoea' within the first three days of life and a usually more severe 'late diarrhoea' from the fourth to the 14th day of life. the latter type of diarrhoea occurred almost exclusively during the first half of the year. thirty-four out of 45 calves with late diarrhoea excreted rotaviruses, whereas only one of 34 calves with e ... | 1980 | 6258202 |
| cyclic amp and permeability coefficient of albumin of the isolated rat mesentery. effects of escherichia coli endotoxin. | we have investigated the mechanisms whereby escherichia coli endotoxin exerts its exudative effects, by using an isolated rat mesentery placed as a separation membrane between the two compartments of a diffusion cell. the permeability coefficient of albumin (pa) can be easily computed from the equilibration rate of 125i-labeled albumin added to one compartment. e. coli endotoxin increased pa in a concentration-related manner. direct measurements revealed an early and transient increase in cyclic ... | 1981 | 6261834 |
| effects of bovine viral diarrhea virus infection on bovine polymorphonuclear leukocyte function. | four procedures were used to evaluate the function of polymorphonuclear leukocytes (pmn) isolated from the blood of cattle experimentally infected with bovine viral diarrhea (bvd) virus: (1) uptake of am emulsion of paraffin oil and escherichia coli lipopolysaccharide, (2) nitroblue tetrazolium reduction, (3) chemiluminescence, and (4) iodination, or the conversion of iodide to a trichloroacetic acid-precipitable form. a marked impairment of iodination was consistently observed after infection w ... | 1981 | 6266288 |
| microbiological studies on hamburgers. | one hundred and eighty-two raw, 112 pre-cooked and 750 cooked hamburgers composed mainly of beef or beef and pork were subjected to microbiological examination.raw hamburgers gave total bacterial counts from 10(6) to 10(8) per g, counts of enterobacteriaceae from 10(4) to 10(6) per g, of escherichia coli from 10(3) to 10(5), of group d streptococci from 10(2) to 10(4), of staphylococcus aureus from 3 to 10(2) and of clostridium perfringens less than 10 bacteria per g. of the samples, 32% contain ... | 1982 | 6276464 |
| enzymatic mechanisms of dna repair. | dna repair proficiency in cells is expressed by various enzymes which can recognize damaged sites arising from exogenous agents or endogenous conditions. either a damaged base is recognized by dna glycosylases, partially removed by hemi-dna glycosylases acting on diadduct damage, or direct incision of the phosphodiester bond near the damaged site. incision at those apurinic or apyrimidinic sites arising from depurination-depyrimidination or glycosylase reactions is effected by apurinic or apyrim ... | 1981 | 6281649 |
| chemotactic requirements of bovine leukocytes. | a system was described for studying bovine leukotaxis. chemotaxis was readily observed toward bovine serum activated by zymosan of agarose. however, bacterial culture filtrates and peptides, which were potent chemotaxins for leukocytes from other species, failed to affect bovine leukotaxis. using conditions suitable for studying binding to leukocytes from other species, specific binding of a radiolabeled chemotactic peptide to bovine leukocytes was not apparent. these data indicate that bovine l ... | 1982 | 6283962 |
| comparison of paired whole milk and dried filter paper samples for anti-enterotoxin and anti-rotavirus activities. | milk specimens, 75 from cows immunized against cholera toxin and 35 from a human population in which enterotoxigenic escherichia coli and rotaviral infections are endemic, were collected as paired filter paper and frozen whole milk samples. each pair was tested for antibody activity against heat-labile e. coli and vibrio cholerae enterotoxins. additionally, 12 of the 35 paired human milk samples stored as frozen whole milk and dried on filter paper were tested for anti-rotavirus immunoglobulin a ... | 1982 | 6286715 |
| passive immunity in calf diarrhea: vaccination with k99 antigen of enterotoxigenic escherichia coli and rotavirus. | twenty-four pregnant cows were vaccinated intramuscularly with k99 extract from enterotoxigenic escherichia coli and inactivated rotavirus as follows: six cows were injected with 2 ml of oil-adjuvanted vaccine; six cows were injected with 0.5 ml of oil-adjuvanted vaccine; six cows were injected with 4 ml of aluminum hydroxide-adjuvanted vaccine twice with a four-week interval; and six cows were unvaccinated as controls. calves born to these cows were challenged with enterotoxigenic e. coli at 6 ... | 1982 | 6288567 |
| specific molecular activities of recombinant and hybrid leukocyte interferons. | hybrid interferon dna recombinants were constructed from the iflra and iflrd leukocyte interferon-coding sequences. each of the hybrid interferons was purified with the use of a monoclonal antibody to human leukocyte interferon. three amino acid residues were identified, one or all of which function to potentiate antiviral activity on feline cells and reduce activity on human cells. because at sufficiently high concentrations human interferons can interact with mouse and rat receptors, it is app ... | 1982 | 6288687 |
| biological activities and spectroscopic properties of chromophoric and fluorescent analogs of adenine nucleoside and nucleotides, 2',3'-o-(2,4,6-trinitrocyclohexadienylidene) adenosine derivatives. | the ribose-modified chromophoric and fluorescent analog of atp 2',3'-o-(2,4,6-trinitrocyclohexadienylidene) adenosine 5'-triphosphate (tnp-atp) has been synthesized previously (hiratsuka, t., and uchida, k. (1973) biochim. biophys. acta 320, 635-647 and hiratsuka, t. (1976) biochim. biophys. acta 453, 293-297). in the present study, four tnp-derivatives of atp, adp, amp and adenosine were synthesized and compared for several chemical, spectral and enzymatic properties. their visible absorption a ... | 1982 | 6295507 |
| expression of cloned calf prochymosin gene sequence in escherichia coli. | an expression plasmid for calf prochymosin (prorennin) cdna was constructed. the plasmid (pcr301) contains the lacuv5 promoter in front of the fused gene in which the codons for the n-terminal four amino acids of prochymosin cdna were replaced with those for the n-terminal ten amino acids of beta-galactosidase. synthesis of the fused protein with the expected mr was detected immunologically in escherichia coli harboring pcr301. the product seemed to be localized in the cell membrane of the bacte ... | 1982 | 6295885 |
| inactivation of spermidine n1-acetyltransferase with alkaline phosphatase. | spermidine n1-acetyltransferase in an extract from phytohemagglutinin-stimulated bovine lymphocytes was inactivated by preincubation with alkaline phosphatase. inactivation of the acetylase with the phosphatase was totally inhibited by addition of pyrophosphate. these results suggest that spermidine n1-acetyltransferase, the rate-limiting enzyme in the biodegradative pathway of polyamines, is inactivated by dephosphorylation. a similar effect of alkaline phosphatase on the acetylase in an extrac ... | 1982 | 6297970 |
| the amino acid sequence of the beta-subunit of atp synthase from bovine heart mitochondria. | the amino acid sequence of the beta-subunit of bovine heart mitochondrial atp synthase has been determined by protein sequence analysis. the polypeptide chain of 478 amino acids is blocked at its nh2 terminal. comparison of this sequence with sequences of the corresponding proteins from escherichia coli (saraste, m., gay, n.j., eberle, a., runswick, m.j., and walker, j.e. (1981) nucleic acids res. 9, 5287-5296) and maize and spinach chloroplasts krebbers, e.t., larrinua, i. m., mcintosh, l., and ... | 1983 | 6298222 |
| the effect of ph, ubiquinone depletion and myxothiazol on the reduction kinetics of the prosthetic groups of ubiquinol:cytochrome c oxidoreductase. | (1) the kinetics of the reduction by duroquinol of the prosthetic groups of qh2:cytochrome c oxidoreductase and of the formation of ubisemiquinone have been studied using a combination of the freeze-quench technique, low-temperature diffuse-reflectance spectroscopy, epr and stopped flow. (2) the formation of the antimycin-sensitive ubisemiquinone anion parallels the reduction of both high-potential and low-potential cytochrome b-562. (3) the rates of reduction of both the [2fe-2s] clusters and c ... | 1983 | 6299337 |
| recovery of a hybrid vector, derived from bovine papilloma virus dna, pbr322 and the hsv tk gene, by bacterial transformation with extrachromosomal dna from transfected rodent cells. | a bovine papilloma virus (bpv)-pbr322-derived recombinant plasmid carrying a 2-kb fragment of herpes simplex virus dna containing the thymidine kinase (tk) gene is capable of transforming tk- cells of mouse l and syrian hamster bhk21 lines to tk+. in transformed cells a small proportion of the plasmid dna is present as extrachromosomal elements while the remainder appears to be integrated into the genome. it was possible to recover plasmids indistinguishable from the input dna by transformation ... | 1983 | 6303907 |
| synthesis of calf prochymosin (prorennin) in escherichia coli. | a gene for calf prochymosin (prorennin) has been reconstructed from chemically synthesized oligodeoxyribonucleotides and cloned dna copies of preprochymosin mrna. this gene has been inserted into a bacterial expression plasmid containing the escherichia coli tryptophan promoter and a bacterial ribosome binding site. induction of transcription from the tryptophan promoter results in prochymosin synthesis at a level of up to 5% of total protein. the enzyme has been purified from bacteria by extrac ... | 1983 | 6304731 |
| expression and regulation of a human metallothionein gene carried on an autonomously replicating shuttle vector. | a human metallothionein (mt) gene was inserted into a bovine papillomavirus (bpv) vector. the chimeric vector (pmtii-bpv) transforms rodent fibroblasts to a cadmium-resistant phenotype. the resistance is due to the high level of expression of human mt-ii in those cells. the vector is maintained in the cells as a free replicating plasmid, present at about 10--15 copies per cell. transcription of the episomal human mt-iia gene is initiated from its authentic start sites and is regulated by the lev ... | 1983 | 6306660 |
| migration of entamoeba histolytica under agarose. | a procedure for visualizing and quantifying motility of entamoeba histolytica by migration under agarose is described. agarose suspended in tissue culture medium 199 supplemented with bovine albumin was poured into plastic dishes and allowed to harden. six pairs of wells were cut out in a circular configuration. to the inner wells a suspension of e. histolytica in eagle's medium (24 x 10(6) cells/ml) was added, and to the outer wells a chemoattractant or the control medium. after overnight incub ... | 1983 | 6309025 |
| influence of intramammary infusion of polymyxin b on the clinicopathologic course of endotoxin-induced mastitis. | the influence of giving 1 dose of polymyxin b (1.6 x 10(6) u/quarter) by the intramammary route to dairy cows to modify the clinicopathologic course of mastitis induced by intramammary infusion of escherichia coli endotoxin (1 mg/quarter) was examined. pretreatment with polymyxin b or its simultaneous administration reduced and delayed the typical febrile and leukopenic responses to endotoxin infusion, prevented an increase in plasma lactate dehydrogenase activity and a reduction in plasma zinc ... | 1983 | 6312850 |
| kinetics and mechanism in the reaction of gene regulatory proteins with dna. | we have measured the kinetic properties of the escherichia coli camp receptor protein (cap) and lac repressor interacting with lac promoter restriction fragments. under our reaction conditions (10 mm-tris x hcl (ph 8.0 at 21 degrees c), 1 mm-edta, 10 microm-camp, 50 micrograms bovine serum albumin/ml, 5% glycerol), the association of cap is at least a two-step process, with an initial, unstable complex formed with rate constant kappa a = 5(+/- 2.5) x 10(7) m-1 s-1. subsequent formation of a stab ... | 1984 | 6319716 |
| poly(adp-ribosylation) of dna topoisomerase i from calf thymus. | we demonstrate that the activity of the major dna topoisomerase i from calf thymus is severely inhibited after modification by purified poly(adp-ribose) synthetase. polymeric chains of poly(adp-ribose) are covalently attached to dna topoisomerase i. these observations with highly purified enzymes suggest that poly(adp-ribosylation) may be a cellular mechanism for modulating dna topoisomerase i activity in response to the state of dna in the nucleus. although extensive poly(adp-ribosylation) of t ... | 1984 | 6323415 |
| clinical pharmacokinetics of carbenicillin, carfecillin, ticarcillin and bl-p 1654 in dairy cows. | the minimal inhibitory concentrations (mic) of carbenicillin, ticarcillin and bl-p 1654 for gram-negative udder pathogens were determined using the agar plate dilution method. the mic of the drugs for 50% and 90% of the isolates examined ranged for escherichia coli and aerobacter spp. from 1.56 to 25 micrograms/ml, and for klebsiella spp. and pseudomonas spp. from 3.12 to 50 micrograms/ml. the serratia spp. were relatively non-susceptible for the drugs studied (mic greater than 50 micrograms/ml) ... | 1984 | 6323731 |
| an enhancer sequence from bovine papilloma virus dna consists of two essential regions. | a comprehensive structural analysis of an enhancer sequence from bovine papilloma virus dna is presented based on the construction and functional analysis of 20 mutant derivatives. the results, obtained in cv-1 tissue culture cells, show that this enhancer is a small genetic element--only 40 bp in length--that contains two essential regions. the two regions exhibit homology to each other and to dna fragments from other viral genomes that also act as enhancers in the assay used. however, there is ... | 1984 | 6324133 |
| plasmidial maintenance in rodent fibroblasts of a bpv1-pbr322 shuttle vector without immediately apparent oncogenic transformation of the recipient cells. | a recombinant plasmid was constructed (pv69) which comprises a subgenomic fragment of bovine papilloma virus type 1 (bpv1) dna, part of plasmid pbr322 dna and a drug resistance gene expressed in both mammalian fibroblasts and escherichia coli. this gene (vv2) is a modified form of the bacterial neomycin resistance gene (neo) linked to the herpes simplex virus thymidine kinase (tk) promoter (plasmid pag60), to which the original bacterial neo promoter from transposon tn5 was added back, upstream ... | 1984 | 6325168 |
| distantly related sequences in the alpha- and beta-subunits of atp synthase, myosin, kinases and other atp-requiring enzymes and a common nucleotide binding fold. | the alpha- and beta-subunits of membrane-bound atp synthase complex bind atp and adp: beta contributes to catalytic sites, and alpha may be involved in regulation of atp synthase activity. the sequences of beta-subunits are highly conserved in escherichia coli and bovine mitochondria. also alpha and beta are weakly homologous to each other throughout most of their amino acid sequences, suggesting that they have common functions in catalysis. related sequences in both alpha and beta and in other ... | 1982 | 6329717 |
| protection against acute, ascending pyelonephritis caused by escherichia coli in rats, using isolated capsular antigen conjugated to bovine serum albumin. | we found that isolated escherichia coli k13 antigen conjugated to bovine serum albumin, in contrast to isolated, non-conjugated k13, was highly immunogenic and induced protection against acute pyelonephritis caused by e. coli o6k13h1 in rats. | 1983 | 6337094 |
| relationship between penetrability of the papillary duct (teat) and phagocytic capability in lactating dairy cows. | to determine whether there is a reciprocal relationship between penetrability of the papillary duct of the teat (streak canal) and phagocytic capability, 3 cows with highly penetrable papillary ducts and 3 with ducts highly resistant against penetration were identified, using a penetrability assay. leukocytes harvested from milk from these cows were tested for their capability to phagocytose staphylococcus aureus. phagocytic capability was found to be independent of the ability of microorganisms ... | 1983 | 6338773 |
| cellular uptake and inhibition of dna synthesis by dihydroxyanthraquinone and two analogues. | three analogues of aminoalkylamino-substituted anthraquinone derivatives, namely, 1,4-dihydroxy-5,8-bis(((2-[(2-hydroxyethyl)amino]ethyl)amino))-9,10-anthracenedione (dhaq), 1-hydroxy-5,8-bis(((2-[(2-hydroxyethyl)amino]ethyl)amino))-9,10-anthracenedione (haq), and 1,4-bis(((2-[(2-hydroxyethyl)amino]ethyl)amino))-9,10-anthracenedione (aq), were chosen with respect to the number of hydroxyl groups on the aromatic ring. dhaq showed about 100 times more potent antiproliferative activity on cultured ... | 1983 | 6339045 |
| depression of b-lymphocytes by mastitis and treatment with levamisole. | proportion of b-lymphocytes in milk and blood decreased simultaneously with development of mastitis induced with endotoxin and recovered with disappearance of clinical signs. however, the change in t-lymphocytes was slight. the reduced percentage of b-lymphocytes was caused by reduction in absolute number of such cells. when used orally, levamisole increased the proportion b-lymphocytes of milk to the same as or more than that of similar cells in peripheral blood. this compound may enhance activ ... | 1983 | 6341425 |
| depurination-induced infidelity of deoxyribonucleic acid synthesis with purified deoxyribonucleic acid replication proteins in vitro. | removal of purine bases from phi x174 single-stranded dna leads to increased reversion frequency of amber mutations when this dna is copied in vitro with purified dna polymerases. this depurination-induced mutagenesis is observed at three different genetic loci and with several different purified enzymes, including escherichia coli dna polymerases i and iii, avian myeloblastosis virus dna polymerase, and eukaryotic dna polymerases alpha, beta, and gamma. the extent of mutagenesis correlates with ... | 1983 | 6344919 |
| the effect of escherichia coli endotoxin and culture filtrate on the dry bovine mammary gland. | the mammary glands of eight non-lactating dairy cows were infused with either endotoxin or the sterile culture filtrate in which escherichia coli had been grown (ccf). animals were necropsied at intervals up to 24 h after infusion. only mild inflammation of the teat and lactiferous sinuses occurred after 4 h, subsiding gradually to 24 h. after mixing dry cow secretion with either endotoxin or ccf, an intense inflammatory response was produced on inoculation of quarters of a lactating cow; ccf al ... | 1983 | 6345601 |
| prognosis for cows with severe clinical coliform mastitis. | a retrospective study was performed at the new york state college of veterinary medicine, ambulatory clinic to determine the prognosis for cows with peracute or acute coliform mastitis. eighty-eight cows were identified by their clinical signs and positive culture of coliform organisms. in 59.1 per cent of the affected cows the quarters returned to a milk-like secretion approximately one month following treatment. the 59.1 per cent was composed of 37.5 per cent (of the initial 88 cows), which mi ... | 1983 | 6346657 |
| isolation and characterization of protease do from escherichia coli, a large serine protease containing multiple subunits. | a new cytoplasmic proteolytic enzyme in escherichia coli, named protease do, has been purified to near homogeneity. the enzyme is an endoprotease that degrades casein, denatured bovine serum albumin, and globin but shows little or no hydrolytic activity against insulin, growth hormone, native bovine serum albumin, or a variety of commonly used peptide substrates. the molecular size of the enzyme was large, and it could be isolated in different preparations in either of two forms. one showed a mo ... | 1983 | 6347072 |
| the effect of trypsin and chymotrypsin on the in vitro antimicrobial and iron-binding properties of lactoferrin in human milk and bovine colostrum. unusual resistance of human apolactoferrin to proteolytic digestion. | the susceptibility of lactoferrin in bovine colostrum and human milk to digestion by trypsin and chymotrypsin has been investigated. neither enzyme had much effect on the lactoferrin-mediated antimicrobial activity of human milk, and the iron binding capacity of lactoferrin in the milk was only slightly reduced. likewise both enzymes had only a slight effect on the iron-binding capacity of purified lactoferrin. although iron-free (apo)lactoferrin was slightly more susceptible to digestion, espec ... | 1983 | 6349699 |
| prospects for development and use of recombinant deoxyribonucleic acid techniques with ruminal bacteria. | over the last decade, developments in recombinant deoxyribonucleic acid techniques and molecular biology have revolutionized bacterial genetics, creating vast, new potential uses of bacteria (as well as animal and plant cells) that were not even considered previously. bacterial production of hormones is but one example. with bacterial species with well developed genetic systems, such as escherichia coli, it is now possible genetically to "design" or "engineer" bacterial strains having specific c ... | 1983 | 6350393 |
| protective effects of antibody against intestinal invasion by escherichia coli. | seven escherichia coli isolates from newborn calves with diarrhea were examined for enteropathogenic properties. one isolate penetrated into hela cells, four produced enterotoxin(s) and the remaining two possessed neither of these properties. penetration of e. coli into hela cells was inhibited by antibody in bovine colostrum and in bovine and rabbit immune sera. the effective antibodies appeared to be mostly of the igm class. the invasion by e. coli isolates was also examined by inoculation of ... | 1983 | 6350831 |
| experimental mastitis with escherichia coli: kinetics of bacteriostatic and bactericidal activities. | three dairy cows were infected on a single mammary gland with 10(4) colony forming units of serum resistant escherichia coli. the inflammatory reaction was monitored by sampling the inoculated glands at 2 h intervals during the first 16 h post-inoculation, then at each milking for five days. spontaneous sterilization occurred after an initial phase of rapid bacterial growth. bovine serum albumin and transferrin (tr) milk levels rose and fell simultaneously, whereas the increase in lactoferrin (l ... | 1983 | 6351707 |
| [circular dichroism of the complexes between poly-l-lysine and dna with different gc contents]. | studies were carried out of circular dichroism spectra of the complexes between poly-l-lysine (pl) and calf thymus dna, e. coli dna, t2--and t7--phage dna, modiolus sp. dna. the results indicate that pl more strongly changes at--dna conformation as compared to gc dna conformation. this change correlates with the size of minimal pl clusters on dna investigated. sequence of dna bases produces almost no effect on conformational changes caused by the complex-formation with pl. | 1983 | 6351932 |
| [colonization factors in escherichia isolated from children with acute intestinal diseases]. | the occurrence of colonization factors cfai/cfaii in 621 e. coli strains isolated from the feces of 147 children with acute intestinal diseases and in 295 e. coli cultures isolated from 59 practically healthy children aged up to 1 year was studied by means of the slide hemagglutination test with a 3% human group b red cell suspension (cfai) and a 3% bovine red cell suspension (cfaii) with 1% d-mannose added. escherichia strains with colonization factors cfai/cfaii were detected in 38 out of 147 ... | 1983 | 6353816 |
| determination of nanogram quantities of osmium-labeled nucleic acids by stripping (inverse) voltammetry. | modification of nucleic acids with oso4 in the presence of pyridine results in a formation of a covalently bound electroactive center in a polynucleotide chain detectable by polarographic (voltammetric) methods. it has been shown that dna modified with osmium (dna-os) accumulates at the hanging mercury-drop electrode during a waiting time in a wide range of potentials between 0 and -1.0 v (against the saturated calomel electrode) and produce at neutral ph a well-developed reduction peak at about ... | 1983 | 6353997 |
| hemolytic complement titers and complement c3 levels in endotoxin-induced mastitis. | escherichia coli lipopolysaccharide b was instilled through the lactiferous duct of cows to induce acute mastitis. hemolytic complement (c) activity and c3 concentrations were determined in blood serum and in renninprecipitated whey before, and at certain times after, mastitis was induced. hemolytic complement activity was detected in the whey only during the first 36 hours after endotoxin was instilled, whereas activity was not seen before and 48 or more hours after the endotoxin was given. the ... | 1983 | 6354013 |
| the effect of antibiotics on mannose-resistant haemagglutination by k88- and k99-positive escherichia coli strains. | five e. coli strains carrying k99 antigen isolated from the intestines of calves which had succumbed to diarrhoea and six k88-positive strains isolated from fatal cases of diarrhoea in piglets were examined for their mannose-resistant haemagglutination (mrha) capacity against pig erythrocytes. the bovine strains showed a geometric mean mrha-titre of 1/18 and the porcine strains one of 1/45. similar experiments were carried out after addition of the following antibiotics in doubling dilutions: am ... | 1983 | 6355504 |
| increase in specific opsonic activity in bovine milk following experimental escherichia coli mastitis. | an infection in a single bovine mammary quarter with a capsulated escherichia coli stimulated a long lasting opsonic activity for the phagocytosis and killing of the homologous strain by polymorphonuclear leucocytes. the induced activity was associated with increases in the igm fraction and an appearance of activity in the igg2 fraction. the capsular polysaccharide was the major inducing antigen, with the immune whey showing opsonic activity for other strains of e coli with antigenically similar ... | 1983 | 6356257 |
| protection of calves against fatal enteric colibacillosis by orally administered escherichia coli k99-specific monoclonal antibody. | a monoclonal antibody (mca) to enterotoxigenic escherichia coli k99 antigen agglutinated k99+ enterotoxigenic e. coli strains b44 (o9:k30;k99;f41:h-) and b41 (o101:k99;f41:h-) grown at 37 degrees c but not at 18 degrees c. the mca, which was characterized as immunoglobulin g1, reacted specifically with k99 antigen in an enzyme-linked immunosorbent assay and precipitated radiolabeled k99 antigen. a total of 45 colostrum-fed and colostrum-deprived calves were used in three separate trials to deter ... | 1983 | 6358029 |
| mastitis caused by hemolytic escherichia coli in the ferret. | hemolytic escherichia coli was isolated from the mammary glands of 8 ferrets with gangrenous mastitis. clinical signs included firm swelling of one or more mammary glands and discoloration of the overlying skin. peracute disease and acute septicemia were observed, and in some cases the animals rapidly became moribund. antibiotic therapy alone did not alter the course of the disease. wide surgical resection of the involved glands in combination with systemic antibiotic therapy (ampicillin 10 mg/k ... | 1983 | 6358164 |
| dna primase associated with 10 s dna polymerase alpha from calf thymus. | among multiple subspecies of dna polymerase alpha of calf thymus, only 10 s dna polymerase alpha had a capacity to initiate dna synthesis on an unprimed single-stranded, circular m13 phage dna in the presence of ribonucleoside triphosphates (dna primase activity). the primase was copurified with 10 s dna polymerase alpha through the purification and both activities cosedimented at 10 s through gradients of either sucrose or glycerol. furthermore, these two activities were immunoprecipitated at a ... | 1983 | 6360214 |
| the clinical manifestation and pathogenesis of enteritis associated with rotavirus and enterotoxigenic escherichia coli infections in domestic animals. | rotavirus and enterotoxigenic escherichia coli (etec) are enteropathogens each capable of inducing diarrhoea in some animal species and man. unstressed young animals develop an age-related resistance to infection with either rotavirus or etec which differs for each animal species. the effects of experimental infection of calves, lambs, foals and piglets with rotavirus and etec given either alone or in combination, have been examined. in general, dual infections tended to lengthen the period of a ... | 1983 | 6361857 |
| single-cell partition analysis--a direct fluorescence technique for examining ligand-macromolecule interactions. | single-cell partition analysis is described as a novel technique for examining ligand-macromolecule interactions. this procedure is a combination of the classical fluorescence titration technique and phase-partition techniques and allows three separate methods for calculating and comparing both free and bound drug concentrations. the value of this technique is demonstrated by the comparison of the binding properties of the potent antitumor antibiotic adriamycin and ethidium bromide to nucleic ac ... | 1983 | 6362483 |
| detection of enzymatic activities in sodium dodecyl sulfate-polyacrylamide gels: dna polymerases as model enzymes. | recent techniques for detecting the catalytic activity of enzymes in sodium dodecyl sulfate (sds)-polyacrylamide gels have been hampered by lack of reproducibility associated with variability in commercial sds preparations. simple expedients which facilitate reproducible detection of dna polymerase activity and which appear to be widely applicable to detection of other enzymes are reported here. it was observed that reproducibility of a reported procedure for dna polymerase detection (spanos, a. ... | 1983 | 6362484 |
| effect of salicylates on intestinal secretion in calves given (intestinal loops) escherichia coli heat-stable enterotoxin. | the inhibitory effect of salicylates on intestinal secretion in 1- to 5-day-old calves given escherichia coli heat-stable enterotoxin (st)-induced intestinal fluid response was investigated. purified st was diluted in isotonic saline solution to obtain 1:10, 1:25, 1:50, 1:75, and 1:100 dilutions. each dilution (1 ml) was inoculated into ligated loops in the distal part of the jejunum of each calf. acetylsalicylic acid (aspirin) given orally (100 mg/kg) at 4 hours before st was inoculated did not ... | 1983 | 6362497 |
| changes in penetrability of bovine papillary duct to endotoxin after milking. | the relative penetrability of bovine papillary ducts was assayed using frequency of inflammatory response to implantation of escherichia coli endotoxin at a depth of 3 mm. penetrability immediately after machine milking, compared with penetrability after delays of 10 to 480 minutes, indicated a decrease in frequency of penetrability to a minimum at 2 hours after milking, a decrease of about 75%. four and 8 hours after milking, frequency of penetrability increased to about 55% of that measured im ... | 1983 | 6362500 |
| experimental mastitis with escherichia coli: sequential response of leukocytes and opsonic activity in milk of immunised and unimmunised cows. | two immunised and three unimmunised cows were challenged in a single mammary gland with 10(4) colony forming units of the vaccinal escherichia coli strain. immunisation comprised subcutaneous injection of killed bacteria with adjuvant at drying-off, and one intramammary infusion (without adjuvant) five weeks later. somatic-cell counts and bacterial counts were monitored throughout the experiment. bactericidal and opsonic properties of milk were assessed before inoculation and at 6, 12, and 24 h ... | 1983 | 6362543 |
| kinetic measurements of escherichia coli rna polymerase association with bacteriophage t7 early promoters. | during infection of escherichia coli by bacteriophage t7, e. coli rna polymerase utilizes only three promoters (a1, a2, and a3). in vitro, the a promoters predominate at very low polymerase concentration, but at higher polymerase concentration the minor b, c, d, and e promoters are used with equal efficiency. the binding constant for the initial association of polymerase with promoters and the forward rate of isomerization to an "open" complex capable of initiation have been measured for the a1, ... | 1984 | 6363413 |
| does the dna methylase eco dam pair nucleotide sequences to form site-specific duplexes? | the eco dam methylase is active on denatured dna and single-stranded synthetic oligonucleotides containing gatc sites. the results suggest that on interaction with single-stranded oligonucleotides the eco dam methylase is able to form a duplex structure within the gatc site, and that this duplex site is a substrate for enzyme. | 1984 | 6368265 |
| [a field experiment using e. coli-k99 vaccine]. | in a field experiment in which vaccine containing e. coli-k99 antigen were administered to approximately thirty per cent of the pregnant dairy cows in herds in which the calves were affected with scours, during the first five days of life (the other animals were treated with a placebo), following results were obtained: the colostrum of vaccinated cows contained significantly higher concentrations of immunoglobulins to e. coli-k99 than did that of controls (table 1). from the start of the experim ... | 1984 | 6369623 |
| study of several factors affecting the agglutinating activity of k99-positive escherichia coli strains. | the effect of several factors on escherichia coli k99-plasmid associated agglutination has been studied. the results obtained indicate that escherichia coli 637 (k99+) mediated red blood cell agglutination is unspecific although the agglutination titres for several erythrocyte species are significantly different. the agglutination is highly stable (at least with sheep red blood cells) to changes in temperature (from 4 degrees c to 37 degrees c), to changes in ph (from 5 to 9) and to the presence ... | 1983 | 6371953 |
| hydrogen peroxide-mediated antagonism against serratia marcescens by streptococcus mitis. | the alpha-hemolytic streptococcus mitis strain no. 17-1, isolated from the oral cavity of an healthy female adult, antagonized the growth of all 24 test strains of serratia marcescens examined; furthermore, this strain inhibited the growth of various strains of staphylococcus aureus, s. epidermidis, streptococcus pyogenes, s. agalactiae, s. pneumoniae, haemophilus influenzae, listeria monocytogenes, and corynebacterium diphtheriae. however, strans of escherichia coli, enterobacter cloacae, klebs ... | 1983 | 6372321 |
| [effect of orally administered bovine lactoferrin and bovine igg on the establishment of escherichia coli in the digestive tract of gnotobiotic mice and human newborn infants]. | the bacteriostatic effect of the association bovine lactoferrin (lf) and bovine igg (igg) was studied in vitro and in vivo against two escherichia coli strains, s17 and emo1, isolated from the faecal flora of mouse and man, respectively. these two strains were sensitive in vitro to the bacteriostatic effect of lf + igg. a kinetic study of the in vivo establishment of e. coli s17 was followed in axenic mice associated with that strain. seven hours after inoculation, no difference was observed in ... | 1983 | 6372577 |
| localisation of enteropathogens in paraffin embedded tissue by immunoperoxidase. | an indirect immunoperoxidase technique has been used to identify enteropathogens in formol-sublimate fixed paraffin embedded sections of calf intestine. infections with bovine rotavirus, bovine coronavirus, newbury agent srv -1, and k99+ escherichia coli have been detected in the intestines from experimentally infected and conventially reared diarrhoeic or normal calves. the ability to visualize enteropathogenic agents in histological sections resulted in the demonstration of virus infected cell ... | 1984 | 6373836 |
| drug resistance and conjugative r plasmids in fecal escherichia coli strains isolated from healthy younger animals (chickens, piglets, calves) and children. | a total of 11,777 escherichia coli strains were isolated from 90 chickens, 103 piglets, 96 calves, and 104 children in 1979 in gunma prefecture and tested for drug resistance and the presence of conjugative r plasmids. the percentages of individuals that excreted drug-resistant strains were: chickens, 100%; piglets, 99%; calves, 100%; and children, 64%. the frequency of isolation of drug-resistant strains among the total isolates was: chickens, 98%; piglets, 93%; calves, 94%; and children, 41%. ... | 1983 | 6374389 |
| infection with enterotoxigenic escherichia coli in calves and protection of the calves by vaccination of the dams. | a report is given of a study on the occurrence of enterotoxigenic escherichia coli in calves in denmark. samples from 1379 1-30-day-old calves were examined and etec were isolated from 228 samples (16.5%). while in 1-2-day-old calves nearly one half (47.5%) harboured etec, the frequency dropped to 3.4% in 8-day-old calves, and of 165 9-30-day-old calves just one was found to harbour etec. a field trial with k99-containing bacterins was performed in 14 herds with etec problems. a total of 109 cow ... | 1983 | 6375531 |
| further studies on the variation among cows, bulls and calves in the ability of their blood polymorphonuclear leucocytes to kill staphylococcus aureus. | 1984 | 6375807 | |
| antimicrobial resistance and conjugative r plasmids in escherichia coli strains isolated from animals in peninsular malaysia. | fifteen independent e. coli strains of avian, bovine and porcine origin in peninsular malaysia were tested for antibiotic resistance and conjugative r plasmids. eight (53%) isolates were found to be antibiotic resistant. among them, 37.5% were mono-resistant and 62.5% were resistant to three or more antibiotics, i.e., multi-resistant. all of them were resistant to tc and sensitive to gm and nx. three of the eight antibiotic resistant strains were able to transfer all or part of their resistance ... | 1984 | 6377513 |
| selective affinity chromatography of dna polymerases with associated 3' to 5' exonuclease activities. | the use of 5'-amp as a ligand for the affinity chromatography of dna polymerases with intrinsic 3' to 5' exonuclease activities was investigated. the basis for this is that 5'-amp would be expected to act as a ligand for the associated 3' to 5' exonuclease. the requirements for binding of escherichia coli dna polymerase i, t4 dna polymerase, and calf thymus dna polymerase delta, all of which have associated 3' to 5' exonuclease activities, to several commercially available 5'-amp supports with d ... | 1984 | 6377960 |
| relationships between linear type scores, objective type measures, and indicators of mastitis. | objectives were to examine the usefulness of objective measures of conformation and linear scores for type for predicting indicators of mastitis. approximately 300 cows in five herds were scored in the experimental linear classification program of the holstein-friesian association of america, measured objectively for numerous components of conformation, and evaluated for four indicators of mastitis. indicators of mastitis were average natural logarithm of somatic cell counts during the lactation ... | 1984 | 6378993 |
| [determination of the nucleotide and isoplith composition of dna by scanning thin-layer chromatograms in ultraviolet light]. | the author studied the uv spectra of the bases and pyrimidine sequences of dna after separation in thin layers of cellulose, and calculated the coefficients permitting the determination of nucleotide and isoplith composition of dna from uv light reflection during thin-layer chromatogram scanning. | 1984 | 6380613 |
| quaternary heterocyclylamino beta-lactams. v. l-640,876 treatment of induced enterotoxigenic colibacillosis (scours) in calves and piglets. | a new semisynthetic cephalosporin antibiotic designated l-640,876, 7-beta-(1-benzylpyridinium-4-yl)amino-3-[( (1-methyl-1h-tetrazol-5-yl)thio] methyl)ceph-3-em-4-carboxylate, was highly active in vitro against 110 enteropathogenic strains of escherichia coli and salmonella species of animal origin. the mic90 was 0.125 microgram/ml for the e. coli strains, 2 micrograms/ml for the s. choleraesuis strains and 4 micrograms/ml for the s. typhimurium strains. in colostrum-fed calves infected with e. c ... | 1983 | 6381448 |
| enumeration of total coliforms, fecal coliforms, and escherichia coli in foods by hydrophobic grid membrane filter: supplementary report. | raw, comminuted poultry meat was used to determine the specificity of the media and incubation conditions used in the hydrophobic grid membrane filter method. confirmation rates for target colonies were 100% for total coliforms, 98% for fecal coliforms, and 97-99% for escherichia coli. the results of total coliform enumeration in 30 pasteurized milk samples by both the hydrophobic grid membrane filter method and aoac method 46.013-46.016 are also reported. | 1984 | 6381469 |
| observations on corynebacterium bovis infection of the bovine mammary gland. ii. experimental infection. | experiments are described in which lactating cows were exposed to corynebacterium bovis either by dipping the teats in a suspension of the bacteria or by inoculating the bacteria into the teat duct or the teat sinus. all three methods readily led to 'infection' being established. the effect of these infections on somatic cell count was minor and no clinical mastitis resulted during the course of the experiments although some cases occurred subsequently. there was evidence that 44% of these infec ... | 1984 | 6381561 |
| coliform mastitis. | many strains of e. coli, klebsiella, and enterobacter can cause udder infection in dairy cows. although some cases are severe, and occasionally fatal, most cases are self-limiting and would be resolved without therapy. chronic coliform infections also occur; these may be subclinical but typically elicit recurrent clinical episodes. therapy of acute coliform infections should be directed at removal of and neutralization of the effects of endotoxin. in cases of endotoxic shock, electrolyte and flu ... | 1984 | 6382775 |
| prostacyclin production by perturbed bovine aortic endothelial cells in culture. | this study reports that endotoxin (escherichia coli serotype 026:b6) and 12-o-tetradecanoyl-phorbol-13-acetate stimulate cultured bovine aortic endothelial cells to generate prostacyclin. the prostacyclin concentration of the culture medium was measured indirectly by radioimmunoassay for 6-keto-pgf1 alpha. the amount of prostacyclin generated depended on the concentration of endotoxin or phorbol diester. prostacyclin generation was not immediate, but occurred slowly after a six-hour lag period. ... | 1984 | 6383496 |
| [characterization of enterotoxigenic escherichia coli of bovine origin by dna-dna colony hybridization]. | dna-dna colony hybridizations with a st1a probe were done on bovine enterotoxigenic escherichia coli strains and compared with the suckling mouse test. the results show that one fourth (7/24) of the strains positive in the baby mouse test do not hybridize the st1a probe and suggest the existence of another or other toxins among the bovine enterotoxigenic e. coli strains. | 1984 | 6385806 |
| tissue specificity of 3'-untranslated sequence of myosin light chain gene: unexpected interspecies homology with repetitive dna. | using the 3' noncoding and coding sequences of chick heart myosin light chain mrna cloned into escherichia coli as probes, it was observed that, while the coding sequence shared homology with myosin light-chain mrnas from other sources, the 3' noncoding sequence was specific for chick heart muscle. this property was used to detect chick heart-specific myosin light-chain gene activity in chick blastoderms of very early developmental stages where cells of different muscle origins cannot be disting ... | 1984 | 6385857 |
| isolation and characterization of the heat stable enterotoxin from a pathogenic bovine strain of escherichia coli. | a heat-stable enterotoxin secreted by a pathogenic strain of escherichia coli of calf origin was purified to homogeneity by a procedure involving acetone fractionation, deae cellulose chromatography, biogel p2 chromatography and size exclusion high pressure liquid chromatography. the purity of the product was ascertained by amino-acid analyses and amino acid sequence using manual degradation with 4-n, n dimethylaminoazobenzene-4' isothiocyanate (dabitc) and an automatic gas phase sequenator. the ... | 1984 | 6388141 |
| virulence factors of escherichia coli isolated from cows with acute mastitis. | a total of 184 escherichia coli isolates recovered from cows with acute mastitis were examined for recognized pathogenic mechanisms and virulence factors commonly found in pathogenic groups of e coli. a modification of the eng procedure (for detecting complement deficiencies in serum) was used to test for resistance to different animal sera. the sereny test (for invasiveness), infant mouse test (for heat-stable enterotoxin), and y-1 adrenal tumor cell assay (for heat-labile enterotoxin) were use ... | 1984 | 6388441 |
| progressive pathology of severe escherichia coli mastitis in dairy cows. | an investigation was made using light and electron microscopy of the progressive pathological changes in nine experimental and two natural cases of severe escherichia coli mastitis in dairy cows. the duration of infection varied from 18 hours to 13 days. epithelial lesions were not found in glands which had been infected for more than 24 hours. however, the epithelia of the sinuses and large ducts became hyperplastic after 60 hours of infection and by six days hyperplasia was extensive on the cr ... | 1984 | 6390590 |
| [fixation of antibodies by covalent bonds to polystyrene: use of the immunoenzyme technic for the detection of escherichia coli k99 in calf feces]. | a solid phase enzyme immunoassay using antibodies covalently bound to polystyrene balls is developed. results show the same sensitivity as the method with antibodies adsorbed to solid support. by means of k99+ e. coli detection on diarrhoeic calves, results are compared with bacteriological findings. the interest of the method is discussed. | 1984 | 6393848 |
| thoughts of the medical microbiologist on the use of antimicrobial drugs in animals. | the restriction in feed-antibiotics as carried out in our country so far did not lead to the expected decrease of r-factors in the faecal flora of the animals staying in stable. possible explanations on this subject are given in this report. the question arises whether the best solution to the problem would not be a complex separation of antibiotics used in human medicine from those used in veterinary medicine, as already discussed in the swann report. a further spreading of plasmids and transpo ... | 1984 | 6395578 |
| a small episode of single quarter coliform infections in lactating dairy cows kept at pasture. | for a period of 150 days, an escherichia coli infection in a single quarter of the udder of 13 cows occurred on average every 9 days, in a herd of 120 cows kept at pasture under temperate environmental conditions. most cases were clinically mild, affecting cows in lactations 1 to 10 and at all stages of lactation; none were evident at calving. samples of secretion from infected quarters sometimes had few demonstrable organisms. eleven different serotypes in 8 (0) groups were recovered; one isola ... | 1984 | 6397184 |
| biochemical and antibacterial properties of bovine mammary secretion during mammary involution and at parturition. | mammary secretions from four holstein friesian cows were collected during late lactation, early involution, and early in subsequent lactation. changes of ph, concentration of serum albumin, immunoglobulin g, citrate, lactoferrin, and number of leukocytes in secretions were typical of milk from glands undergoing these physiological transitions. whey prepared from a cow's secretions was evaluated for its capacity to inhibit growth of escherichia coli, 60-lilly, and a coliform strain isolated from ... | 1984 | 6397483 |
| effect of e. coli ectotoxin on calcium and phosphate concentration in serum of dairy cows. | the injection of e. coli ectotoxin into eight healthy cows of the srb breed induced a significant hypocalcemia and hypophosphatemia. a clinical profile similar to that normally seen in paresis puerperalis was also observed. these results confirm earlier observations that toxaemia can give rise to paralytic symptoms. | 1984 | 6397719 |
| [pathogenic role of strains of specific escherichia coli serotypes in the development of mastitis in cows. i. clinical course]. | the studies were carried out on 14 cows. for infection of the cows pathogenic (from the field) e. coli strains from the serological groups: 093, 010,086 and non pathogenic strains (museum) belonging to serogroups: 0132, 0120, 093 were used. the microorganisms of each group were injected into the udders of two cows. two successive cows were injected into the udders e. coli endotoxin (group 093). in 6 hr after infusion of the strain or endotoxin, the experimental quarters were swollen, reddened, b ... | 1984 | 6399553 |
| an enzymatically active antigen-antibody probe to measure circulating immune complexes. ii. e. coli beta-galactosidase in the probe and c1q as the recognition unit. | an enzymatically active probe (beta-galactosidase-anti-beta-galactosidase complex) is used to measure circulating immune complexes (cic), in a competition assay where probe and cic are confronted with a 'recognition unit'. the latter is bovine conglutinin in the original description of this method. here we describe a version utilizing human or bovine c1q. the two techniques are compared for their sensitivity and specificity, on both in vitro formed tetanus toxoid-anti-toxoid complexes and on ser ... | 1983 | 6404986 |
| f41 antigen among porcine enterotoxigenic escherichia coli strains lacking k88, k99, and 987p pili. | colonial morphological variations among enterotoxigenic escherichia coli which lack k88, k99, and 987p (3p-) were shown to be correlated with expression of several surface antigens, i.e., type 1 pili, f41 pili, and somatic and capsular antigens. such correlations were established by electron microscopy, serology, and hemagglutination of cells derived from these specific colonial types. identification of f41 produced by the 3p- enterotoxigenic e. coli strains was made by immunodiffusion in agaros ... | 1984 | 6420345 |
| evaluation of a surfactant mixture c31g as a teat dip by a modified excised teat model. | a mixture of amphoteric surfactants with antimicrobial properties, c31g, was evaluated as a teat dip by a modified excised teat model. the model was modified to avoid misinterpretation of results from indigenous bacterial microflora on teats. in three experiments, bacterial numbers recovered from teats dipped in .75, 1.5, and 3.0% solutions of c31g were compared with bacteria recovered from undipped teats (negative controls) and teats dipped with 1.0% iodophor (an effective teat dip). mean log r ... | 1984 | 6425375 |
| functional groups at the catalytic site of bf1 adenosinetriphosphatase from escherichia coli. | the rates of inactivation of bf1 adenosinetriphosphatase (bf1-atpase) from escherichia coli by 7-chloro-4-nitro-2,1,3-benzoxadiazole, 1-fluoro-2,4-dinitrobenzene, 2,4,6-trinitrobenzenesulfonate, phenylglyoxal, and n,n'-dicyclohexylcarbodiimide have been measured in the presence and absence of various concentrations of inorganic phosphate, adp, atp, or magnesium ion. dissociation equilibrium constants and rate constants for the labeling reactions have been deduced from a quantitative treatment of ... | 1982 | 6462170 |
| assessment in the mouse of cefoperazone as a treatment for mastitis. | the value of cefoperazone in mastitis therapy was assessed in the mouse model of mastitis primarily by its effect on bacterial cell numbers in the gland. in addition histological studies showed that the drug was not an irritant in the mammary gland. pharmacokinetic studies showed that it was slowly absorbed from the gland (six days to absorb 500 micrograms) but was easily removed by milking. in ascending order of efficacy cefoperazone (500 micrograms/gland) was active against four-hour-old intra ... | 1984 | 6464327 |
| a role for dna polymerase in the specificity of nucleotide incorporation opposite n-acetyl-2-aminofluorene adducts. | escherichia coli dna polymerase i (klenow fragment), dna polymerase alpha from both calf thymus and human lymphoma cells and dna polymerase beta from calf thymus and novikoff hepatoma cells can incorporate nucleotides opposite n-guanin-8-yl-acetyl-2-aminofluorene in dna. the polymerases incorporate dctp opposite some aaf-dg lesions when mg2+ is the divalent cation. substitution of mn2+ for mg2+ broadens the specificity of insertion: e. coli dna polymerase i (klenow fragment) also inserts a, and ... | 1984 | 6492159 |
| pathomorphology and pathogenesis of bacterial meningoventriculitis of neonatal ungulates. | bacterial meningoventriculitis was studied in 26 neonatal ungulates. preceded by a substantial bacteremia, usually due to escherichia coli, the fibrinopurulent inflammation involved leptomeninges, choroid plexuses, and ventricle walls, but largely spared the neuraxial parenchyma. it is proposed that this surface-relatedness results from the transport of bacteria by monocytes of low bactericidal power, migrating by normal pathways to maintain significant surface populations of macrophages. the ne ... | 1984 | 6516179 |
| development of a competitive enzyme-linked immunosorbent assay (elisa) for escherichia coli heat-stable enterotoxin (sta). | a sensitive competitive enzyme-linked immunosorbent assay (elisa) was developed to detect the low molecular weight heat-stable enterotoxin (sta) in culture supernatant fluids of enterotoxigenic escherichia coli (etec). competitive inhibition was observed between sta in solution and a glutaraldehyde-coupled sta-human serum albumin (hsa) conjugate bound to microtiter wells when antiserum raised against a glutaraldehyde-coupled sta-bovine serum albumin (bsa) conjugate was used as detecting antibody ... | 1984 | 6520401 |
| evaluation of experimental teat dip containing sodium chlorite and lactic acid by excised teat assay. | an experimental teat dip containing sodium chlorite and lactic acid, diluted in water, was evaluated by excised teat protocol. the teat dip was tested against 21 microorganisms. included were: staphylococcus aureus, streptococcus agalactiae, streptococcus dysgalactiae, streptococcus uberis, escherichia coli, klebsiella oxytoca, klebsiella pneumoniae, and pseudomonas aeruginosa. numerous strains were tested for strain differences. environmental bacteria were included because of their increasing i ... | 1984 | 6530497 |
| molecular cloning and sequence determination of rat preproenkephalin cdna: sensitive probe for studying transcriptional changes in rat tissues. | a cdna probe was prepared to investigate the regulation of proenkephalin biosynthesis in the rat. this was necessary because human and bovine proenkephalin cdna were not sensitive enough for the accurate detection of preproenkephalin mrna in tissues that contain low copy numbers of this message, such as the adrenal gland. the rat probe was prepared in the following manner. preproenkephalin mrna was enriched by sucrose gradient centrifugation of poly(a)-containing mrna from rat brain and was used ... | 1984 | 6594709 |
| urea--dna glycosylase in mammalian cells. | urea-dna glycosylase, an enzyme presumed to be active in the repair of dna damage caused by oxidizing agents, has been identified previously in escherichia coli. this enzyme has now been shown to be present in cell extracts of calf thymus and human fibroblasts. it catalyzes the release of free urea from a double-stranded polydeoxyribonucleotide containing thymine residues fragmented by kmno4 and naoh treatment. the calf thymus enzyme has been 400-fold purified and largely separated from previous ... | 1983 | 6626501 |
| tetrahydrobiopterin is synthesized by separate pathways from dihydroneopterin triphosphate and from sepiapterin in adrenal medulla preparations. | using escherichia coli guanosine triphosphate cyclohydrolase, dihydroneopterin triphosphate was synthesized from guanosine triphosphate and was compared with sepiapterin as a substrate for tetrahydrobiopterin formation in bovine adrenal medulla extracts. the dihydrofolate reductase inhibitor, methotrexate, blocks the formation of tetrahydrobiopterin from sepiapterin but not from dihydroneopterin triphosphate. reduced nicotinamide adenine dinucleotide phosphate and a divalent metal ion are requir ... | 1983 | 6639080 |
| chemical and immunological properties of escherichia coli heat-stable enterotoxin. | five heat-stable enterotoxins (sts) produced by enterotoxigenic e. coli (etec) strains of porcine, bovine and human origin have been purified to apparent homogeneity. the sts with biological activity in suckling mice and piglets (sta) contained 18 amino acid residues, 10 or 11 different amino acids with a high proportion of acidic amino acids and 6 half-cystines. all 5 purified preparations were heat-stable, not denatured by organic solvents and detergents, resisted protease digestion and treatm ... | 1983 | 6686335 |
| fatal mastitis of dairy cows: a retrospective study. | the necropsy records of dairy cows with mastitis were reviewed from the provincial veterinary laboratory in guelph (44 cases of mastitis in nine years) and from the ontario veterinary college (168 cases in 14 years). mastitis was considered to be the primary cause of death in 167 of 212 cows (79%). of these 167 cases of mastitis, escherichia coli was involved in 107 (64%), klebsiella sp. in 12 (7%) and staphylococcus aureus in 11 (7%). bacteriology was not reported in 22 cases. coliform mastitis ... | 1984 | 6722641 |
| fluorogenic substrates for bacterial aminopeptidase p and its analogs detected in human serum and calf lung. | a sensitive fluorimetric assay was developed for bacterial aminopeptidase p, based on intramolecularly quenched fluorogenic substrates. two substrates were synthesized. phe(no2)-pro-hn-ch2-ch2-nh-abz (substrate i) and phe(no2)-pro-pro-hn-ch2-ch2-nh-abz (substrate ii), in which the phe(no2) group (rho-nitro-l-phenylalanyl) quenches the fluorescence of the abz group (omicron-aminobenzoyl). both substrates were readily cleaved by aminopeptidase p from escherichia coli, releasing rho-nitro-l-phenyla ... | 1982 | 6749499 |
| evaluation of immunological methods for detection of bovine growth hormone (bgh) produced in e. coli. | the use of several immunological methods for studies on synthesis of bovine growth hormone (bgh) by e. coli is described here. the elisa procedure was shown to be the least sensitive and unfit for assaying bgh in e. coli extracts. the solid-phase radioimmunoassay (ria) proved to be highly sensitive, but since e. coli extract itself (not containing bgh) interfered with the immunological reaction, its use for measuring bgh was practically limited. the best adequate procedure proved to be radioimmu ... | 1982 | 6749998 |
| inhibition of calf thymus dna polymerase alpha and of normal and cancer cell growth by butylanilinouracil and butylphenylguanine. | 6-(p-n-butylanilino)uracil and n2-(p-butylphenyl)guanine inhibited the activity of dna polymerase alpha from calf thymus but had no effect on other eukaryotic polymerases (dna polymerases beta and gamma) or escherichia coli dna polymerase i. inhibition was competitive with deoxyguanosine 5'-triphosphate and did not occur in the reaction of dna polymerase alpha with a template that did not contain cytosine residues. the results support a mechanism which involves hydrogen bonding of inhibitors wit ... | 1982 | 6756479 |
| enhancement of the chemotactic response of bovine polymorphonuclear leukocytes by levamisole. | the effects of levamisole on random migration, chemotaxis, phagocytosis, and intracellular killing by bovine polymorphonuclear leukocytes (pmn) were investigated. chemotactic assays were performed, using micropore filters in modified boyden chambers. phagocytosis and intracellular killing of escherichia coli were analyzed by standard viable bacterial counts. results indicated that levamisole enhanced the chemotactic response of pmn at concentrations ranging from 10(-4) to 5 x 10(-3)m. phagocytes ... | 1982 | 6762119 |