Publications
| Title | Abstract | Year(sorted descending) Filter | PMID Filter |
|---|
| the pathogenesis of enteric colibacillosis in neonatal unsuckled calves. | the development of pathological lesions in the small intestine of neonatal calves is described. seven newborn calves were challenged orally with a known enteropathogenic strain of e coli 0101k?(a) and killed at varying times after inoculation. adhesion of bacteria to the mucosa of the small intestine was observed in all calves. a few organisms were seen in the distal small intestine at three hours after inoculation and thereafter adhesion progressed anteriorly along the intestine in calves kille ... | 1979 | 390852 |
| 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 ... | 1979 | 435240 |
| diethylaminoalkyloxycoumarin and -furocoumarin derivatives. | four series of diethylaminoalkoxyderivatives of coumarin (at the positions 4 and 7) and furocoumarin (at the positions 5 and 8) have been prepared, in order to study their complexing capacity with dna, these compounds having a double possibility of interaction, that is intercalation of the aromatic moiety between two base pairs and formation of an electrostatic bond between their terminal amino group and a phosphoric group of dna. some biological effects connected with the interaction with dna h ... | 1979 | 399924 |
| [immunobiological activity of various blood serum fractions from cattle and swine. the dynamics of ig in specific serum against colibacillosis in pigs]. | the level of the igm and igg agglutinating antibody specific hyperimmune serum against coli-bacteriosis and its fractions were studied. the serum was obtained at various stages of the preparation, hyperimmunization and exploitation of serum producing swine by using the 2-mercapto-ethanol test. it was established that serum of the total globulin, alpha-beta-globulin and gamma-globulin fractions contains igm and igg agglutinating antibodies against e. coli. these immunoglobulin classes are synthet ... | 1979 | 396718 |
| 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 ... | 1979 | 393149 |
| the survival of serum resistant escherichia coli in the bovine mammary gland following experimental infection. | serum resistant strains of escherichia coli were injected into one or two quarters of the udders of eight healthy dairy cows. animals receiving infection into two quarters showed variation in their ability to eliminate the bacteria. this variation extended from elimination from both glands to complete failure to remove the organisms from either gland. in most cases, the organisms were removed from one gland before the clinical signs of infection were observed, but persisted in the other gland fo ... | 1979 | 382316 |
| early mitochondrial damage in the induction of haemorrhagic necrosis in the crocker sarcoma (s 180) by endotoxin. | disturbances in the functional properties of tumor mitochondria have been studied during the course of induction of haemorrhage brought about by endotoxin in the murine crocker sarcoma (s 180). extensive impairment of function was already present in mitochondria isolated from control tumors, as shown by low respiratory control ratios. the existing mitochondrial damage intensified promptly in response to injection of endotoxin long before the onset of haemorrhage at 4 h. the nature of the additio ... | 1979 | 381316 |
| binding of phosphorylated histone h1 to dna. | a chromatin associated protein kinase was used to add 3 moles of phosphate to seryl side chains of 1 mole of histone h1. the dna binding properties of this in vitro phosphorylated h1 were compared with those of unmodified h1. considerably more radioactive superhelical dna was retained on nitrocellulose filters at 20mm-40mm nacl by phosphorylated h1 than by unmodified h1. however, zone velocity sedimentation analysis of histone-dna complexes indicated that similar amounts of phosphorylated and un ... | 1978 | 209406 |
| glycoproteins of natural origin with an affinity for hepatitis b surface antigen. | sera from certain animal species contain a substance(s) which binds hepatitis b surface antigen. the hepatitis b binding substance found in animals is not antibody, but appears to be a glycoprotein which reacted with antigen-coated beads and produced a "false positive" test for antibody. this glycoprotein could be selectively and quantitatively removed by reaction with purified hepatitis b surface antigen and centrifugation. pili fractions isolated from neisseria gonorrhoeae and escherichia coli ... | 1978 | 213390 |
| elisa: enzyme-linked immunosorbent assay. | similar in design to radioimmunoassay, comparable in sensitivity and specificity but easier, safer, and less expensive, this new diagnostic technique uses enzyme-labeled rather than isotope-labeled reagents. the end point is a color change that can be assessed by colorimetry or with the naked eye. various techniques of elisa are described, along with examples of current and potential clinical applications. | 1978 | 215505 |
| the sources of "oh" serotypes of escherichia coli. | the sources from which different "oh" serotypes of escherichia coli have been isolated are listed in a series of tables. it is considered that these tables should provide a basis for obtaining a greater understanding of the ecology of e. coli. | 1978 | 340583 |
| in vitro adhesion of escherichia coli to porcine small intestinal epithelial cells: pili as adhesive factors. | escherichia coli strains with pili (k99 or 987p) known to facilitate intestinal colonization adhered in vitro to porcine intestinal epithelial cells. these strains adhered equally to both ileal and jejunal epithelial cells. a laboratory e. coli strain that has type 1 pili also adhered to porcine intestinal epithelial cells. when nonpiliated cells derived from 987p+, k99+, or type 1 pilus+ strains were used for in vitro adhesion assays, they failed to adhere. the attachment of piliated bacteria t ... | 1978 | 357285 |
| biological evaluation of a methanol-soluble, heat-stable escherichia coli enterotoxin in infant mice, pigs, rabbits, and calves. | escherichia coli p16 was shown to produce two heat-stable toxins (st) with differing biological activity. the toxins were separated by methanol extraction, and the first, sta, was methanol soluble, partially heat stable, active in neonatal piglets (1 to 3 days old) and infant mice, but inactive in weaned pigs (7 to 9 weeks old); the second, stb, was methanol insoluble, active in weaned pigs and rabbit ligated loops, but inactive in infant mice. it is therefore suggested that use of suckling mice ... | 1978 | 357288 |
| microscopic assay for the phagocytotic-collagenolytic performance (pcp index) of human gingival fibroblasts in vitro. | using 16 human gingival fibroblasts cell lines from patients with periodontitis, dilantin hyperplasia, and nonpathological gingiva, a microscopic assay was developed to quantitate the cells' ability to lyse collagen substrates. the method employs tissue culture chambers with one cover slip partially coated with a thin layer of undenatured fibrillar bovine collagen. the assay measures the relative numbers and sizes of holes in the collagen within defined regions of the cover slips effected by the ... | 1978 | 363754 |
| localization of the site of adenylylation of glutamine synthetase by electron microscopy of an enzyme-antibody complex. | antibodies to the nucleosidel,n(6)-ethenoadenosine have been used to localize the site of adenylylation of the glutamine synthetase [l-glutamate:ammonia ligase (adp-forming), ec 6.3.1.2] of escherichia coli. antibodies were induced in rabbits by injection of a bovine albumin-ethenoadenosine conjugate. the resulting antisera strongly bound ethenoadenosine, its 5'-nucleotide, or protein conjugates of the nucleoside; little or no crossreaction was seen to adenosine, amp, or the protein carrier. eth ... | 1978 | 32536 |
| new surface-associated heat-labile colonization factor antigen (cfa/ii) produced by enterotoxigenic escherichia coli of serogroups o6 and o8. | enterotoxigenic escherichia coli (etec) belonging to serogroups o6 and o8 do not possess the h-10407-type colonization factor antigen (cfa/i). however, these frequently isolated etec were found to possess a second and distinct heat-labile surface-associated colonization factor antigen, termed cfa/ii. whereas cfa/i mediates mannose-resistant hemagglutination of human group a erythrocytes, cfa/ii does not. cfa/ii mediates mannose-resistant hemagglutination of bovine erythrocytes, and mannose-resis ... | 1978 | 80383 |
| hygiene in the prevention of udder infections. iv. evaluation of teat dips with excised cows' teats. | suspensions of staphylococcus aureus, streptococcus agalactiae, escherichia coli, and pseudomonas aeruginosa were used to contaminate teats excised from cows. commercially available teat dips were applied for evaluation of comparative germicidal activity. iodophors, sodium hypochlorite, and sodium dichloro-s-triazenetrione were highly effective against all four test organisms. quarternary ammonium, chlorhexidine, and cetylpyridinium chloride were effective against staphylococcus aureus, and stre ... | 1978 | 100535 |
| [microbiological studies on bacterial spectra of milk samples from healthy udder quarters and from those with increased cell counts and/or conductivity values]. | the germ levels of 2,182 milk samples obtained from udder quarters with subclinical mastitis were compared to milk sampled from 2,061 udder quarters with physiological cell counts or conductivity values. three cattle herds were involved in the test programme. no germ growth was established from 9.5 per cent of all samples taken from udder quarters with increased cell counts and conductivities and from 4.1 per cent of those samples taken from intact udder quarters. samples taken from udder quarte ... | 1978 | 104694 |
| incidence and relationship of group d streptococci with other indicator organisms in meats. | raw and processed meats were analyzed for presumptive group d streptococci using kf streptococcus agar. counts were compared with coliform, presumptive escherichia coli, and enterobacteriaceae counts but no meaningful relationships were observed. results indicated that group d streptococci and e. coli type i were principally contaminants from the packing plant, rather than at retail level. the predominating group d streptococcus in both beef and pork cuts was streptococcus faecalis, while in pro ... | 1978 | 106944 |
| use of polyvalent cow colostrum in the prevention of enteric infections in calves and piglets. | colostrum of cows immunized with a polyvalent vaccine against enteropathogenic strains of escherichia coli gave good protection to piglets and calves against enteric coli infections. bovine immunoglobulin (igg1) and its precipitable fragments persisted in the small intestine of piglets for 6 hours after oral administration. the proteolytic breakdown of porcine colostral igg2, which occurs predominantly in the small intestine proceeded at a higher rate than that of heterologous bovine colostral i ... | 1978 | 371506 |
| purification of 3-phosphoglycerate kinase from diverse sources by affinity elution chromatography. | 1. affinity elution chromatography was used to purify phosphoglycerate kinase from a variety of sources. the choice of buffer ph for the chromatography was made according to the relative electrophoretic mobility of the enzyme from the species concerned. 2. outlines of the methods used to isolate the enzyme from over 20 sources are presented. the enzyme was purified from the muscle tissue of a variety of mammals, fish and birds, from liver of several animals, from yeast, escherichia coli, and pla ... | 1978 | 367367 |
| incidence of colicinogenic escherichia coli in sheep, goats and cattle. | 1978 | 367012 | |
| lutropin stimulation of rna synthesis in corpus luteum chromatin. | lutropin and human choriogonadotropin stimulated the endogenous chromatin-associated polymerase activity in purified chromatin prepared from nuclei of bovine corpus luteum. chromatin was incubated in two different buffer systems: one that mainly supports the activity of polymerase i, another that supports the activity of polymerase ii and is largely alpha-amanitin sensitive. the hormones lutropin and chorigonadotropin stimulated an increase in the rate of incorporation of [14c]atp or [14c]utp in ... | 1977 | 329886 |
| 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 ... | 1977 | 836806 |
| [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 ... | 1977 | 849749 |
| 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 ... | 1977 | 918925 |
| [dynamics of agglutinins following vaccination against coli-bacteriosis in calves]. | a bivalent vaccine, produced with strains escherichia coli 078 and 0117 to control colibacteriosis in calves, was used to vaccinate experimentally 20 cows following up the agglutinin dynamics in the serum of calves born later on. it was found that the agglutinin titers of the 0 antibodies were lower than those of ok, and varied within the range of from 1:10 to 1:320, the titers of 1:20-1:40 values being prevalent. highest level of titers was observed by the third day following birth. ok antibodi ... | 1977 | 337649 |
| methodology for recognition of invasive potential of escherichia coli. | surveillance for dysentery-related invasive potential in bacteria using the sereny keratoconjunctivitis test is restricted by expense, time factor, and necessity for confirmation. primary screening of isolates in a standardized mammalian cell culture system is recommended. bacteria are grown 20 hr in veal infusion, washed, and resuspended in 20% heat-inactivated fetal bovine serum (fbs) supplemented with 0.12% brain heart infusion and 0.1% bile salts. the hela culture is grown 20 hr as a monolay ... | 1977 | 323215 |
| inhibitory action of galactose on phagocytes from normal and hypergalactosemic chicks. | the inhibitory effect of galactose on phagocyte function was investigated in normal and hypergalactosemic chicks by monitoring the in vitro killing of escherichia coli by leukocytes and the in vivo clearance of colloidal 125i-labeled bovine serum albumin ([125i]bsa) from the circulation. elevated levels of galactose (30 mm) significantly impaired the bactericidal activities of leukocytes from both control and hypergalactosemic chicks. however, the latter cells were more susceptible to the galact ... | 1977 | 326668 |
| thermal denaturation and template activities of reconstituted dna-histone complexes. | reconstituted complexes of dna with histone were prepared by salt-and-urea step gradient dialysis. the dna was complexed with histone h1, with the combination of the other four histones h2a, h2b, h3 and h4, and with whole histones. these dna-histone complexes were purified by bio-gel column chromatography, and the weight ratio of histone-to-dna was determined in each complex. the thermal denaturation profile and nuclease digestion pattern of dna-histone h2a, h2b, h3 and h4 complex were compatibl ... | 1977 | 146400 |
| the transfer of bacterial biotin genes to escherichia coli k-12 cells by transfection with lambda bio phage dna. | the transfection of biotin genes to biotin negative escherichia coli k-12 cells with donor dna isolated from transducing lambda bio phages was examined. the transfection of the cells was performed in the presence of bovine serum albumin and sucrose (osowiecki and skalińska, 1974). | 1977 | 70968 |
| [biochemical and serological studies of the e. coli strains isolated from cows with subclinical mastitis]. | studies were serologically and biochemically a total of 17 strains of escherichia coli isolated from mastitis-affected cows in the districts of sofia, varna, and plovidiv. demonstrated were the serogroups 0125, 0111, 086, 025, 026, 055, and 0128, which were pathogenic for humans too. via the milk they were shown to reach both newborn animals and children and to cause severely expressed colienteritis. all investigated strains attacked glucose and manite, reduced nitrates into nitrites, and gave a ... | 1977 | 343354 |
| transcription of double-stranded rna by escherichia coli dna-dependent rna polymerase. | double-stranded rna of some virus genomes can be used as template for the dna-dependent rna polymerase purified from escherichia coli. the rna synthesis requires all four nucleoside triphosphates and manganese ions and is dependent on the presence of sigma subunit. the reaction is inhibited by rifampicin, streptolydigin and ethidium bromide, but not by dnase and actinomycin d which does not bind to double-stranded rna. the template activity of double-stranded rna from various viruses is differen ... | 1977 | 320006 |
| occurrence of k99 antigen on escherichia coli isolated from pigs and colonization of pig ileum by k99+ enterotoxigenic e. coli from calves and pigs. | several strains of enterotoxigenic escherichia coli (etec) isolated from pigs were found to have an antigen (k99) previously reported only on strains of calf and lamb origin and which facilitates intestinal colonization in the latter two species. several human etec were also tested for k99; however, none were positive. each of four k99-positive etec strains of calf origin and one of pig origin produced k99 in pig ileum in vivo, adhered to villous epithelium in pig ileum, colonized pig ileum, and ... | 1977 | 321356 |
| acute undifferentiated neonatal diarrhea of beef calves: the prevalence of enterotoxigenic e. coli, reo-like (rota) virus and other enteropathogens in cow-calf herds. | 1977 | 326373 | |
| blastogenic transformation by lipopolysaccharide of blood leukocytes from immunized but not normal cattle. | escherichia coli lipopolysaccharide produced blastogenic transformation in whole-blood leukocytes from heifers that had been infected and immunized with campylobacter fetus, but not in cells from control animals. this suggests that lipopolysaccharide dose not function as a b-cell mitogen in cattle and that its stimulation of cells from immunized animals occurred through another mechanism. | 1977 | 330414 |
| [studies of immunity in mastitis in cows]. | studies were carried out to establish the specific antibodies in the milk and blood sera of cows recovered from a spontaneous infection of the udder caused by streptococci, staphylocci, corynebacteria, and some representatives of escherichia coli as well as of cows immunized with a polybacterial vaccine. followed up was likewise the resistance of the udder in vaccinated cows to bacterial infections. it was found that in both groups of animals the specific antibodies' titer ranged from 1:80 to 1: ... | 1977 | 331658 |
| effect of tetracycline upon transfer of an r plasmid from calves to human beings. | fecal specimens from human subjects in daily contact with calves shedding escherichia coli containing an r plasmid were analyzed for the presence of e coli and the plasmid. a low level of crossover was found to occur unrelated to whether or not the calves were receiving tetracycline. | 1977 | 333999 |
| [escherichia coli cell competence induced by calcium cations]. | escherichia coli k-12 cells grown to early and late exponential, and early and late stationary phases were treated with ca2+ and analysed for the ability of exogenous 14c-dna uptake and genetic transformation. dna-membrane complexes were detected detected by isopicnic centrifugation of cell lysates in sucrose density gradient. it is found that 1) during all the tested phases of the growth cycle, e. coli cells attain the ability of enhanced dna uptake after ca2+ treatment; 2) exogenous and host d ... | 1977 | 334632 |
| resistance of neonatal calves given colostrum diet to oral challenge with a septicemia-producing escherichia coli. | twenty holstein-friesian male calves were obtained within 4 hours after bith (colostrum deprived) and allotted to 1 of 4 groups, each given a different feeding: colostrum, milk replacer, polyvinylpyrrolidone (pvp), and saline solution (0.85% nacl). each calf was fed 2 l of the respective diets every 12 hours. rectal temperatures were recorded and blood samples were collected immediately before each feeding. at approximately 27 hours of age, all calves were inoculated orally with 1.5 x 10(10) via ... | 1977 | 335927 |
| mammary blood flow during experimental escherichia coli endotoxin induced mastitis in goats and cows. | the effect of intramammary infusion of escherichia coli endotoxin upon mammary blood flow was studied in lactating goats and cows. blood flow was recorded by means of an electromagnetic flow probe chronically implanted around one mammary artery. endotoxin mastatis was always accompanied by a significant increase in mammary blood flow, characterized by 2 conspicuous peaks. the flow returned to control values by the thirteenth hour after infusion. other symptoms of acute mastitis were: fever, incr ... | 1977 | 338650 |
| studies on the immunity of the calf to colibacillosis--vii: the experimental reproduction of enteric colibacillosis in colostrum-fed calves. | eight newborn calves were challenged orally with a known enteropathogenic strain of escherichia coli 0101 k?(a) and two to six hours later each calf was fed a minimum of three pints colostrum. all calves suffered from acute diarrhoea of varying severity within 24 to 48 hours of infection. immunofluorescent and histological examination of the small intestine demonstrated adherence of the challenge organism to the epithelium and the presence of pathological lesions similar to those seen in colostr ... | 1977 | 339479 |
| biochemical characteristics of enterotoxigenic and nonenterotoxigenic escherichia coli isolated from calves with diarrhea. | eighteen isolates of enterotoxigenic escherichia coli (etec) and 15 isolates of nonenterotoxigenic e coli (netec) obtained from calves with diarrheal disease were characterized biochemically. of 64 biochemical tests employed, none allowed making differentiation of etec from netec. eleven tests were used to separate etec isolates into 1 of 5 biotypes, although the ability to ferment dulcitol, salicin, sucrose, and sorbose gave sufficient information to identify the 5 biotypes of etec. the biotype ... | 1977 | 339791 |
| in vitro packaging of uv radiation-damaged dna from bacteriophage t7. | when dna from bacteriophage t7 is irradiated with uv light, the efficiency with which this dna can be packaged in vitro to form viable phage particles is reduced. a comparison between irradiated dna packaged in vitro and irradiated intact phage particles shows almost identical survival as a function of uv dose when escherichia coli wild type or pola or uvra mutants are used as the host. although uvra mutants perform less host cell reactivation, the pola strains are identical with wild type in th ... | 1977 | 330877 |
| proposed calfhood immunization program for the commercial dairy herd. | immunization programs never will usurp the central role of sound management practices and good nutrition in the disease prevention program of the commercial dairy operation. however, certain immunizations against diseases such as brucellosis, leptospirosis, and clostridial infections should be routine. other diseases such as infectious bovine rhinotracheitis, bovine virus diarrhea, parainfluenza-3, colibacillosis, and pasteurellosis should be considered if it can be determined that the herd is i ... | 1977 | 190280 |
| 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 ... | 1976 | 774989 |
| experimental neonatal colibacillosis in cows: serological studies. | serological studies of passive immunity in experimentally induced bovine colibacillosis was studied in a 41-cow university herd. pregnant dams were antigenized prepartum with two injections administered by the subcutaneous and intrammamary routes with one of four vaccine preparations (killed bacteria, live bacteria, culture supernatant, or heart infusion broth [control]). the data indicate that 77% of the neonates born to vaccinated dams were strongly protected against oral challenge with escher ... | 1976 | 765285 |
| [residues of antimicrobial materials in the effluents of livestock farms (author's transl)]. | forty water samples were taken from streams of three different regions of belgium, with intensive husbandry and examined for residual microbiological activity. in some samples, activity was detected against staphylococcus aureus; none of them were active against e. coli and c. albicans. the substances in the few positive samples were not identified. with this low activity and the small proportion of positive samples (12 out of 41) any influence on the water biosphere due to the methods of farmin ... | 1976 | 766304 |
| 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 ... | 1976 | 764873 |
| vaccination of cows with an escherichia coli bacterin for the prevention of naturally occurring diarrheal disease in their calves. | a formalin-killed escherichia coli bacterin composed of 6 enterotoxigenic strains of the organism prepared from calves with diarrheal disease with field tested for efficacy against naturally occurring diarrheal disease in young calves. the bacterin was tested in 23 privately owned beef herds in montana involving 3,508 cows and their calves. about half the cows in each herd were given 2 subcutaneous vaccinations before calving and the other half (controls) were injected twice with a placebo. almo ... | 1976 | 779544 |
| etiologic diagnosis of diarrheal disease of calves: frequency and methods for detecting enterotoxin and k99 antigen production by escherichia cola. | escherichia coli isolated from calves in minnesota and montana were tested for enterotoxigenicity via bio-assay of cell-free broth culture fluid and for k99 antigen via a serum agglutination test. infant mice were used to assay for heat-stable enterotoxin (st), and adrenal cells in culture were used to assay for heat-labile enterotoxin (lt). forty-six of the 345 e coli isolates produced st enterotoxin, but none produced lt enterotoxin. thirty-five of the 46 enterotoxigenic isolates had k99 antig ... | 1976 | 786085 |
| [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 ... | 1976 | 786200 |
| [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 ... | 1976 | 786201 |
| occurrence and characteristics of enterotoxigenic escherichia coli isolated from calves with diarrhea. | of 1,004 isolates of escherichia coli obtained during the spring of 1975 in seven different states from calves with diarrhea, 124 isolates were enterotoxigenic based upon ability to cause distention of the calf ligated intestinal segment. isolates of enterotoxigenic e. coli (etec) were obtained from calves in six of the seven states. etec were detected in calves in 118 of 355 herds in montana during the 1974 and 1975 spring beef calving seasons. the occurrence and serotypes of etec isolated from ... | 1976 | 776828 |
| effect of coliform challenge at milking time on new udder infections. | this project was designed to study rates of infection in udders of cows exposed to an escherichia coli broth culture at milking time. forty holstein cows of varied stages of lactation were divided randomly into three treatment and one control group of ten cows each. the treatment groups were exposed for 3 wk to an escherichia coli broth of 10(9) colony forming units per ml at milking time by either 1) dipping teat ends in broth before milking, 2) spraying the udder and leaving it dripping wet du ... | 1976 | 777057 |
| changes in intestinal structure and function of neonatal calves infected with reovirus-like agent and eschericia coli. | measurements of villus/crypt length ratio and mucosal beta-galactosidase activity were made on calves less than 3 weeks of age which had diarrhoea associated with reovirus-like agent and e. coli. in calves with diarrhoea, the villus/crypt length ratios at all sites examined along the small intestine were less than in normal calves of similar age. this was attributed to a reduction in length of vili in calves infected with the reovirus-like agent. the activity of mucosal beta-galactosidase in the ... | 1976 | 189746 |
| characterization of enterotoxigenic bovine escherichia coli. | among 300 isolates of bovine escherichia coli, 56 which had been found enterotoxigenic in calf gut loops were characterized on the basis of o and k antigens, colonial morphology and resistance to seven antimicrobial drugs. the 56 isolates enterotoxigenic in the calf were compared with the nonenterotoxigenic ones. of the 56 enterotoxigenic e. coli the majority possessed the a type of k antigen and had ok groups, o9:k(ps274) or o101:k(rvc118). fourteen of these isolates had the k99 antigen. none o ... | 1976 | 793694 |
| 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 ... | 1976 | 796669 |
| leukocyte inhibiting factor (lif) production from human lymphocytes stimulated by bacterial lipopolysaccharides. | leukocyte inhibiting factor (lif) release from lymphocytes cultures stimulated by bacterial lipopolysaccharides (lps) has been investigated. human lymphocytes cultured in the presence of e, coli or s. enteritidis lps were able to release in the supernatants a substance with the following properties: a) same elution pattern of bovine serum albumin (mw 69000) when filtered on sephadex g-100; b) it migrates on disc electrophoresis a an albumin; c) not dialyzable; d) not cytotoxic; e) inhibition of ... | 1976 | 798596 |
| control of rna synthesis by chromatin proteins. | the effect of chromatin proteins on template activity has been studied. using both e. coli rna polymerase and calf thymmus polymerase b we have measured the number of initiation sites on chromatin and various histone-dna complexes. chromatin can be reconstituted with histone proteins alone and this complex is still a restricted template for rna synthesis. the removal of histone f1 causes a large increase in the template activity. chromatin is then treated with micrococcal nuclease and the dna fr ... | 1976 | 787926 |
| pathogenesis and treatment of escherichia coli infections in calves. | two clearly defined types of e. coli infection are recognised and the factors predisposing and giving rise to pathogenicity are discussed. the mode of action of enterotoxins in the secretary mechanism is thought to be through stimulation of adenyl cyclase activity. treatment and prevention of the disease is considered in relation to the pathogenesis of the infection. | 1976 | 792447 |
| pathological and microbiological observations made on spontaneous cases of acute neonatal calf diarrhea. | the purpose of this report is to describe clinical signs, gross and microscopic lesions, bacteriological and immunofluorescence observations made on spontaneous cases of acute neonatal calf diarrhea (ncd) in dairy and beef herds. the following diagnostic tools were used: 1) direct smears of intestinal content, 2) escherichia coli counts, 3) aerobic bacterial cultures of the small intestine and other organs (the o serogroup and the enterotoxigenicity of the e. coli isolated was determined), 4) de ... | 1976 | 793692 |
| local immune responses in the bovine fetus vaccinated in utero with escherichia coli antigen. | using specific immunofluorescent examinations, the local immune responses were studied in 14 calves prenatally vaccinated (10 to 50 days before birth) with escherichia coli (o26:k60:nm) antigen or sterile saline solution. all calves were colostrum-deprived, were given oral doses of homologous organisms (killed or live), and were necropsied either at birth or within 12 days after birth. immunofluorescent plasma cells were not seen in duodenum, jejunum, jejunal lymph nodes, ileum, ileal lymph node ... | 1976 | 769610 |
| a study of the enzymic dephosphorylation of beta-casein and a derived phosphopeptide. | beta-casein, and the phosphate containing peptide derived from it by tryptic digestion, have been dephosphorylated by the action of two phosphatases. escherichia coli alkaline phosphatase (ec 3.1.3.1) has been shown to remove the phosphates from these substrates in two distinct stages. substrate molecules retaining three of the original phosphoseryl residues accumulate during the reaction and are resistant to further dephosphorylation at low enzyme concentrations. in contrast bovine spleen phosp ... | 1976 | 187232 |
| 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 ... | 1976 | 1270145 |
| 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 ... | 1976 | 776048 |
| cytidine diphosphate diglyceride of bovine brain. positional distribution of fatty acids and analysis of major molecular species. | a method is described for the isolation of cdp-diglyceride from bovine brain. yields of the product ranged from 9.2-15.5 mumol per kilogram of tissue, which corresponds to about 1% of the level of phosphatidic acid. mild alkaline hydrolysis of the product gave three water-soluble phosphate esters which had the same electrophoretic mobilities as cmp, cdp-glycerol and glycerol 3-phosphate. the liponucleotide was quantitatively hydrolysed by cdp-diglyceride hydrolase from escherichia coli to phosph ... | 1976 | 776622 |
| 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 ... | 1976 | 778493 |
| 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. | 1976 | 773532 |
| ]acute severe mastitis in cows of the dutch-friesian breed (author's transl)]. | one hundred cases of severe acute mastitis are reported. bacteriological examination of the milk was negative in 23% of the cases. e. coli was most frequently found to be the causative organism (23%), followed by st. aureus (19%), c. pyogenes (10%), str. dysgalactiae (9%), str. agalactiae (5%) and a number of other pathogenic agents such as atypical streptococci, str. uberis, haemolytic streptococci, aerobacter aerogenes, kl. pneumoniae, a clostridium and p. multocida. in several cases, a tentat ... | 1976 | 818734 |
| 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 ... | 1976 | 825148 |
| [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 ... | 1976 | 828991 |
| [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 ... | 1976 | 828997 |
| [indices of bacteriological purity of milk obtained in cowsheds during mastitis controla1]. | 1976 | 797599 | |
| bronchiectasis in yearling feedlot cattle. | thoughout all of 1974, we surveyed, for illnesses and deaths, about 407,000 yearling feedlot cattle. from the 3,943 dead cattle, 1,988 necropsies were made; of the cattle necropsied, 32 (1.6%) had bronchiectasis. in this disease, the permanently dilated small bronchi and bronchioles, located in ventral parts of the lungs, were filled with accumulations of exudate and microorganisms, including pasteurella hemolytica, pasteurella multocida, corynebacterium pyogenes, escherichia coli, salmonella an ... | 1976 | 956033 |
| specific binding of a nonhistone chromosomal protein from lymphocyte to dna. | the isolation of a nonhistone chromosomal protein, nh30 000, from bovine lymphocytes by affinity chromatography on a dna-agarose column is described. the procedure starts with nonhistone fraction nh4 obtained by hydroxyapatite chromatography as described previously [blüthmann, h., mrozek, s. & gierer, a. (1975) eur. j. biochem. 58, 315-326]. protein nh30 000 migrates as a single band with a molecular weight of 30 000 on sodium dodecylsulfate polyacrylamide gels. it contains, on a molar basis 25. ... | 1976 | 1009927 |
| 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. | 1976 | 795819 |
| 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 ... | 1976 | 1255490 |
| [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 ... | 1975 | 813355 |
| 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 ... | 1975 | 813560 |
| [etiology of mastitis in dairy cows in slovakia during 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 was 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 - 1. ... | 1975 | 814671 |
| 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 ... | 1975 | 1090454 |
| 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 ... | 1975 | 1090521 |
| calf ligated intestinal segment test to detect enterotoxigenic escherichia coli. | the ligated intestinal segment test in the young calf was utilized to establish the enterotoxigenicity of approximately 600 escherichia coli isolates obtained from fecal specimens intestinal contents of calves with diarrheal disease. one hundred and fifty isolates were routinely tested in a single calf. there was little problem with false-positive reactions. false-negative reactions normally occurred only if the isolate was tested in the posterior 3 m of the small intestine. the ligated small in ... | 1975 | 1090536 |
| [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 ... | 1975 | 1091204 |
| 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 ... | 1975 | 1187514 |
| [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 ... | 1975 | 1096359 |
| studies on indoleamine 2,3-dioxygenase. i. superoxide anion as substrate. | indoleamine 2,3-dioxygenase purified to apparent homogeneity from rabbit intestine was inhibited by scavengers for superoxide anion such as superoxide dismutase and 1,2-dihydroxybenzene-3,5-disulfonic acid (tiron). on the other hand, beta-carotene and 1,4-diazobicyclo-(2,2,2)-octane, scavengers for singlet oxygen, did not affect the enzyme activity significantly. the degree of inhibition of the dioxygenase by superoxide dismutase preparations from bovine erythrocytes, green peas, spinach leaves, ... | 1975 | 238993 |
| the radiometric assay of alkaline phosphatase activity with 125-i-labelled phenolphthalein monophosphate. | the coupling of 125-i to phenolphthalein monophosphate is described. hydrolytic cleavage of the phosphate group by alkaline phosphatases (ec 3.1.-3.1) releases labelled phenolphthalein which is extracted into ethyl acetate at ph 10. this forms the basis of a sensitive assay for the enzyme with the advantages of sensitivity and rapidity from the use of a gamma-emitter. results with escherichia coli and calf intestine alkaline phosphatases are presented. | 1975 | 237639 |
| properties of a dna-adenylate complex formed in the reaction between mammalian dna ligase i and dna containing single-strand breaks. | the major dna ligase from calf thymus (mammalian dna ligase i) forms a covalent enzyme-amp complex on incubation with atp [söderhäll & lindahl, j. biol. chem. 248, 672-675, (1973)]. the reaction of this complex with dna has now been studied. when the ligase-adenylate complex is incubated at 0 degrees c for short time periods with dna containing single-strand breaks, a dna-amp complex can be isolated from the reaction mixture by isopycnic centrifugation in cscl. incubation at ph 6.5 increased the ... | 1975 | 235425 |
| 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 ... | 1975 | 1104259 |
| 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 ... | 1975 | 1091639 |
| 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 ... | 1975 | 1092386 |
| 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 ... | 1975 | 1093143 |
| 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 ... | 1975 | 1094215 |
| isolation and characterization of cytidine diphosphate diglyceride from beef liver. | cytidine diphosphate diglyceride was isolated from beef liver by a combination of silicic acid column, deae-cellulose column, and this layer chromatography. the product (5.8 to 17.4 mumol/kg of liver) contained cytidine/phosphate/fatty acids in the molar proportions 1.05/2.0/2.05 (theoretical, 1.0/2.0/2.0) (average for three preparations). the liponucleotide was split quantitatively by a partially purified hydrolase from escherichia coli, specific for cdp-diglyceride, (raetz, c. r. h., hirschber ... | 1975 | 169258 |
| demonstation that thymine dimers are excised as oligonucleotides from specifically incised ultraviolet-irradiated deoxyribonucleic acid. | the average size of the dimer-containing acid-soluble oligonucleotides after incubation of specifically incised dna with two dimer excising nuclease activities has been determined to be about 8 nucleotides. | 1975 | 164436 |
| endonuclease ii of escherichia coli: dna reacted with 7-bromomethyl-12-methylbenz[alpha]anthracene as a substrate. | an endonuclease ii preparation from escherichia coli makes single strand breaks in dna which has been treated with the carcinogen 7-bromomethyl-12-methylbenz[alpha]anthracene. in addition, the enzyme preparation excises n6-(12-methylbenz[alpha]anthracenyl-7-methyl)adenine and n2-(12-methylbenz[alpha]anthracenyl-7-methyl)guanine residues from the dna. these are relased as the modified purine bases, not as purine nucleoside derivatives. the rate of release of the adenine derivative is three to fo ... | 1975 | 812550 |
| 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 ... | 1975 | 1095074 |
| 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 ... | 1975 | 1097246 |