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Query: EC:3.1.21.3 (deoxyribonuclease)
 1,528 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Whole sheets of plasma membrane, each with their attached flagellum, were purified from Trypanosoma brucei. The method devised for their isolation included a new technique of cell breakage that used a combination of osmotic stress followed by mechanical sheer and avoided the problem of extreme vesiculation as well as the trapping of organelles in cell 'ghosts'. The purified membranes all contained the pellicular microtubular array. The antigenic surface coat was completely released from the plasma membrane during the isolation procedure. The membranes had a very high cholesterol/phospholipid ratio (1.54). A large proportion (42%) of the cellular DNA was recovered in the plasma-membrane fraction unless a step involving deoxyribonuclease treatment, which decreased the DNA content to less than 13%, was included before secrose-density gradient centrifugation. This step also aided the separation of plasma membranes from other cellular components. The ouabain-sensitive Na+ + K+-stimulated adenosine triphosphatase and adenylate cyclase co-purified with the plasma membranes. Although 5'-nucleotidase was thought to be a plasma-membrane component, it was easily detached from the membrane. The purified membranes were essentially free of L-alanine-alpha-oxoglutarate aminotransferase, L-asparte-alpha-oxoglutarate aminotransferase, malate dehydrogenase, oligomycin-sensitive adenosine triphosphatase, glucose 6-phosphatase, Mg2+-stimulated p-nitrophenyl phosphatase and catalase.
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PMID:The isolation and partial characterization of the plasma membrane from Trypanosoma brucei. 48 94

A comprehensive review of the methods which have been utilized for the identification of staphylococci is presented. Biochemical characteristics which have assisted in the primary isolation of staphylococci, such as pigmentation, hemolytic activity, the egg yolk phenomenon, and deoxyribonuclease and coagulase production, are also analyzed. The potential applicability of advanced techniques to identify staphylococci, such as the detection of enterotoxin production, base ratio analysis, cell wall analysis, phage typing, and serology, is discussed. The following procedures are recommended for routine use: Idnetification of Staphylococcus sp. (clinical laboratories): microscopic observation, catalase activity, coagulase production, lysostaphin sensitivity, and (optional) facultative growth in thioglycolate medium. Identification of Staphylococcus aureus (food laboratories): microscopic observation, catalase activity, coagulase production, thermonuclease production, and (optional) lysostaphin sensitivity.
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PMID:The identification of staphylococci in clinical and food microbiology laboratories. 79 25

A total of 176 strains identified as Branhamella catarrhalis were isolated from various clinical specimens, mainly sputum (71), pharynx (49), eye (24), nose (11), ear (6) and tracheal aspirate (7). B. catarrhalis appeared as Gram-negative cocci in white colonies which were oxidase- and catalase-positive and which did not produce acidification of sugars. The 3 related species, Neisseria caviae, N. ovis and N. cuniculi were also white but the 'true asaccharolytic Neisseria' studied presented a yellow pigment. Only a few strains of B. catarrhalis were able to grow on selective medium. However, when Catlin's chemically defined medium was used, all strains of B. catarrhalis had a unique requirement for arginine. This characteristic differentiated B. catarrhalis from N. caviae and N. ovis (non-requiring), N. cuniculi (required cystine, proline and arginine) and N. canis and N. elongata (both non-requiring). All strains of B. catarrhalis reduced nitrate and nitrite, possessed deoxyribonuclease activity and hydrolysed tributyrin to butyric acid. B. catarrhalis liberated high concentrations of butyric acid, N. caviae, N. ovis and N. cuniculi moderate concentrations and other species of Neisseria minimal concentrations. All strains of B. catarrhalis were resistant to acetazolamide and the absence of gamma-glutamyl transferase activity differentiated B. catarrhalis from atypical meningococci which were always positive.
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PMID:Branhamella catarrhalis. New methods of bacterial diagnosis. 287 8

A total of 56 strains of Campylobacter jejuni (C. jejuni) isolated from diarrhoeal patients were characterized by biochemical tests. The following reactions were performed: hydrolysis of hippurate, reduction of nitrate and nitrite, activity of deoxyribonuclease, hydrolysis of Tween(R) 40, 60 and 80. Including the hydrolysis of the different Tweens(R), 14 biotypes could be distinguished. 19 out of the 56 strains of C. jejuni and the nomenclatural type strains of C. jejuni, C. coli, C. laridis, C. fetus subsp. fetus, subsp. venerealis, C. faecalis, C. sputorum subsp. sputorum, subsp. mucosalis, subsp. bubulus were examined for the production of volatile (VFA) and non-volatile (NVFA) short-chain fatty acids using high performance liquid chromatography (HPLC) with a column for organic acids (Aminex HPX-87 H). A standard mixture of 21 short-chain fatty acids was taken as reference. By this method 5 biotypes of C. jejuni could be characterized. The most frequent biotype was type 1 (78.9%). All the biotypes produced succinic, acetic and butyric acids. Differences existed in the production of pyruvic, malonic, formic and isobutyric acids. C. jejuni could rapidly and clearly be distinguished from C. coli, C. fetus subspp. and catalase-negative Campylobacter species. No qualitative differences were found between the subspecies of C. fetus, C. sputorum subsp. sputorum and subsp. bubulus, C. sputorum subsp. mucosalis and C. faecalis were characterized by presence of fumaric and malonic acid, respectively.
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PMID:Studies on the identification of Campylobacter species using biochemical tests and high-performance liquid chromatography. 391 63

The relationship of catalase, cystinase, and deoxyribonuclease activity to toxinogeny in Corynebacterium diphtheriae was examined. Mutants deficient in each activity were isolated after mutagenization of strain C4 with nitrosoguanidine. All mutants were converted to toxinogeny after lysogenization with beta-converting phage, thus establishing that there is no absolute link between toxin production and these enzymatic activities. No differences were observed in the rate of lysogenization of the mutants by beta-converting phage over that of the parental strain. However, the data suggest that catalase mutants lysogenic for beta phage are generally induced at a higher rate than the parental strain after irradiation with ultraviolet light. Cystinase mutants vary widely in their rate of induction whereas the deoxyribonuclease mutants are similar to the parental strain. The relationship of these results to the production of toxinogenic strains is discussed.
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PMID:Toxinogeny in Corynebacterium diphtheriae after loss of catalase, cystinase, or deoxyribonuclease activity. 419 20

Auletta, Angela E. (Catholic University, Washington, D.C.), and E. R. Kennedy. Deoxyribonucleic acid base composition of some members of the Micrococcaceae. J. Bacteriol. 92:28-34. 1966.-Thirty-seven strains from the genera Micrococcus, Staphylococcus, Gaffkya, and Sarcina were examined for deoxyribonucleic acid base composition and biochemical activity. Organisms were tested for production of catalase, coagulase, deoxyribonuclease, oxidase, phosphatase, hydrogen sulfide, indole, and acetoin; nitrate reduction; gelatin, starch, and urea hydrolysis; citrate and ammonium phosphate utilization; NaCl tolerance; growth at 10 and 45 C, and growth in litmus milk. They were tested for production of acid from dextrose and mannitol under anaerobic conditions, and for aerobic production of acid from dextrose, mannitol, lactose, sucrose, raffinose, maltose, xylose, and glycerol. Organisms could be divided into two groups on the basis of guanine-cytosine (GC) content. Group I had an average GC content of 32%, and included all organisms which produced acid from dextrose. Group II had an average GC content of 62%, and included those organisms incapable of producing acid from dextrose under anaerobic conditions. Sarcina ureae had a GC content of 43%.
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PMID:Deoxyribonucleic acid base composition of some members of the Micrococcaceae. 594 Dec 82

Simultaneous testing for clumping factor, coagulase, deoxyribonuclease, and thermonuclease was performed on 189 clinical isolates of gram-positive cocci with strong catalase activity to determine the suitability of the thermonuclease test as a routine procedure for the identification of Staphylococcus aureus. Positive reactions to all four tests were exhibited by 72 of the strains while 88 of the isolates gave uniformly negative results. Although discrepancies were found between the reactions of 29 organisms, differences were found between the reactions of 29 organisms, differences between tube coagulase ant thermonuclease results were rare. Greater than 90% of positive reactions for both tube coagulase and thermonuclease tests were detected within a four-hour incubation period. The thermonuclease test was found to be simple, reliable, inexpensive and rapid. This test gave easily interpretable reactions within an eight-hour workday, even when only one or two isolated colonies were used for testing. The thermonuclease test is well suited for use as a primary clinical laboratory procedure for the identification of Staphylococcus aureus.
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PMID:Clinical laboratory evaluation of the thermonuclease test. 680 7

The survival of Staphylococcus aureus was studied in 30 oral administration liquid medicaments (15 syrups and 15 solutions) to determine the effectiveness of the preservatives, the influence of the culture medium used in the enumeration of the surviving microorganisms, and the loss of the enzyme coagulase, phosphatase, DNase (deoxyribonuclease), and thermonuclease. Samples were inoculated with 6.3-6.5 x 10(5) viable cells per milliliter and were stored at room temperature for 60 days. Aliquots were taken for analysis at 0, 15, 22, 30, and 60 days after samples were inoculated. The enumeration of S. aureus was made by most probable number method (MPN) with six liquid culture media: triptone soy (TS), TS with 10% NaCl (TSS), TS and TSS with 0.2% catalase, Mannitol salt, and Tellurite-mannitol-glycine. The survival of S. aureus was lower in solutions than in syrups, decreased with the storage time, and depended on the culture medium utilized in the enumeration. Nonselective media were more sensitive than selective ones; that is, a better percentage of recovery was achieved with TS and the catalase medium. The preservative was effective in 93.3% of the samples. Coagulase was the most stable enzyme and phosphatase, DNase, and thermonuclease disappeared during the storage period.
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PMID:Survival of Staphylococcus aureus in oral administration liquid medicaments and influence of count medium on survival. 844 30

Sperm were incubated for up to 9 days in the presence or absence of exogenous hydrogen peroxide, phenylalanine, catalase and aurintricarboxylic acid to assess the influence of reactive oxygen species and inhibition of deoxyribonucleases on sperm chromatin stability. The assessment of sperm DNA susceptibility to in situ acid denaturation by the sperm chromatin structure assay did not detect any difference in chromatin stability between sperm incubated for 9 days under aerobic and anaerobic conditions in a diluent called 14G. Exposure to exogenous hydrogen peroxide under both aerobic and anaerobic conditions and to phenylalanine under aerobic conditions (which produces hydrogen peroxide by a reaction catalysed by the aromatic amino acid oxidase present in sperm) was detrimental to sperm chromatin stability, increasing its DNA susceptibility to in situ acid denaturation over the incubation time. This effect was eliminated if catalase was present in the diluent. Inclusion of the general deoxyribonuclease inhibitor aurintricarboxylic acid in the diluent severely decreased sperm chromatin stability under both aerobic and anaerobic conditions. Aurintricarboxylic acid was mildly cytotoxic, as revealed by viability assessment, under aerobic, but not under anaerobic, incubation conditions. Exogenous hydrogen peroxide, either directly added to the diluent or generated through the enzymatic oxidation of phenylalanine, was detrimental to sperm motility and the integrity of the plasma membrane.
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PMID:Changes in susceptibility of bovine sperm to in situ DNA denaturation during prolonged incubation at ambient temperature under conditions of exposure to reactive oxygen species and nuclease inhibitor. 1145 Oct 15

We have previously shown that inhibition of catalase and glutathione peroxidase activities by 3-amino-1,2,4-triazole (ATZ) and mercaptosuccinic acid (MS), respectively, in rat primary hepatocytes caused sustained endogenous oxidative stress and apoptotic cell death without caspase-3 activation. In this study, we investigated the mechanism of this apoptotic cell death in terms of nucleosomal DNA fragmentation. Treatment with ATZ+MS time-dependently increased the number of deoxynucleotidyl transferase-mediated nick end-labeling (TUNEL)-positive nuclei from 12 h, resulting in clear DNA laddering at 24 h. The deoxyribonuclease (DNase) inhibitor, aurintricarboxylic acid (ATA), completely inhibited nucleosomal DNA fragmentation but the pan-caspase inhibitor, z-VAD-fmk was without effects; furthermore, the cleavage of inhibitor of caspase-activated DNase was not detected, indicating the involvement of DNase(s) other than caspase-activated DNase. Considering that endonuclease G (EndoG) reportedly acts in a caspase-independent manner, we cloned rat EndoG cDNA for the first time. Recombinant EndoG alone digested plasmid DNA and induced nucleosomal DNA fragmentation in isolated hepatocyte nuclei. Recombinant EndoG activity was inhibited by ATA but not by hydrogen peroxide, even at 10 mm. ATZ+MS stimulation elicited decreases in mitochondrial membrane potential and EndoG translocation from mitochondria to nuclei. By applying RNA interference, the mRNA levels of EndoG were almost completely suppressed and the amount of EndoG protein was decreased to approximately half the level of untreated cells. Under these conditions, decreases in TUNEL-positive nuclei were significantly suppressed. These results indicate that EndoG is responsible, at least in part, for nucleosomal DNA fragmentation under endogenous oxidative stress conditions induced by ATZ+MS.
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PMID:Involvement of endonuclease G in nucleosomal DNA fragmentation under sustained endogenous oxidative stress. 1640 72


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