Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.1.25.1 (deoxyribonuclease)
 1,471 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Treponema pallidum (Nichols) was extracted from infected rabbit tissue, and cell lysates were prepared for monitoring thymidine kinase and deoxyribonucleic acid polymerase activities. No thymidine kinase could be demonstrated in preparations of T. pallidum or the cultivable T. phagedenis biotype Reiter. Significant levels of deoxyribonucleic acid polymerase were detected in both treponemal samples. Interestingly, comparisons of polymerase activity among a spectrum of bacterial genera revealed a direct correlation between enzyme concentrations and estimated generation time. Incorporation of [3H]uridine and [3H]thymidine into macromolecules by intact T. pallidum and the Reiter treponeme was examined. Selective ribonuclease-deoxyribonuclease digestion and cesium chloride gradient banding demonstrated that T. pallidum, independent of the host, and T. phagedenis were capable of synthesizing deoxyribonucleic acid only from the [3H]-uridine precursor.
 ...
PMID:Capacity of virulent Treponema pallidum (Nichols) for deoxyribonucleic acid synthesis. 37 16

We previously demonstrated that pneumococcal extracts contain a highly specific inhibitor of human neutrophil elastase (HNE). We now show that the active inhibitor in these extracts is a high-molecular-weight, heat-stable substance that appears to be RNA, since inhibitory activity of pneumococcal extracts is decreased by incubation with ribonuclease but not by incubation with deoxyribonuclease or proteinase K. Moreover, metabolically labeled ([3H]uridine) pneumococcal RNA, isolated by phenol extraction followed by ethanol precipitation, strongly inhibits HNE. Pneumococcal capsular polysaccharide, although polyanionic, is only weakly inhibitory toward HNE and is not a major source of elastase-inhibitory activity in pneumococcal extracts. On the other hand, the capsule of Haemophilus influenzae type b contains polyribosylribitol phosphate. This highly charged polyanion possesses HNE-inhibitory activity, but only under special circumstances to be discussed below. Pneumococci (type I, type II smooth, type II rough) and H. influenzae (type b) all release HNE-inhibitory activity into their culture medium during growth. By contrast, Klebsiella pneumoniae and Staphylococcus aureus release little (if any) stable HNE-inhibitory activity during growth. We propose that some bacterial pneumonias may spare host tissue because polyanions released by the invading microorganisms (e.g. RNA from autolysing pneumococci) inhibit elastase released from inflammatory neutrophils and thereby modulate accompanying tissue proteolysis. Pneumonias caused by microorganisms that do not release stable polyanionic inhibitors of HNE (e.g., Staphylococcus and Klebsiella) may be correspondingly more injurious to the lung.
 ...
PMID:Inhibition of human neutrophil elastase by bacterial polyanions. 244 47

Plagemann, Peter G. W. (Western Reserve University, Cleveland, Ohio), and H. Earle Swim. Replication of mengovirus. II. General properties of the viral-induced ribonucleic acid polymerase. J. Bacteriol. 91:2327-2332. 1966.-Mengovirus induces the appearance of a ribonucleic acid (RNA) polymerase activity in Novikoff hepatoma cells which is readily distinguished from the deoxyribonucleic acid (DNA)-dependent RNA polymerase since it is not inhibited by actinomycin D or deoxyribonuclease, but is inhibited by ammonium sulfate, and is stable at -17 C. The incorporation of uridine into RNA by infected cells in the presence of actinomycin D does not reflect the viral polymerase activity as measured in cell-free preparations. The viral-induced RNA polymerase is produced in a biphasic fashion. Puromycin inhibits the production of viral polymerase, and in its presence the enzyme appears to be unstable between 4 and 6 hr. Puromycin also prevents the secondary rise in polymerase which begins at the end of replicative cycle. Under these conditions, however, the polymerase appears to be stable. The overall data indicated that some unspecified process is responsible for the apparent instability of viral-induced RNA polymerase between 4 and 6 hr and that it becomes inoperative toward the end of the replicative cycle.
 ...
PMID:Replication of mengovirus. II. General properties of the viral-induced ribonucleic acid polymerase. 428 86

Rapidly labeled RNA was extracted from monkey cells after infection with Simian Virus 40 (SV40) and exposure to short pulses of [5-(3)H]uridine late in infection. When this RNA was self-annealed, it became resistant to digestion with ribonuclease. The fraction of RNA that resisted the ribonuclease treatment decreased with increased labeling time, or when a short pulse of radioactivity was followed by incubation with unlabeled uridine and actinomycin D. The RNase-resistant RNA was isolated by chromatography on Sephadex G-100 and shown to be double-stranded by its susceptibility to ribonuclease as a function of salt concentration and temperature. This behavior was not due to RNA-DNA hybrid formation, since deoxyribonuclease had no effect upon the double-stranded molecules, even after their denaturation. The relation of the double-stranded RNA to SV40 was demonstrated by the hybridization of about 50% (corrected value, >90%) of the separated RNA strands with component I of SV40 DNA from plaque-purified virus. After self-annealing in formamide at low temperature, about 10% of the rapidly labeled, viral RNA sedimented at 13 S. This value corresponds in size to about 60% of the SV40 DNA.These observations indicate that late in infection of monkey cells, SV40 DNA is transcribed symmetrically over a considerable portion of its length, and that subsequently some sequences from one or both of the RNA strands are degraded.
 ...
PMID:Extensive symmetrical transcription of Simian Virus 40 DNA in virus-yielding cells. 434 93

Spermatozoa from the cauda of the epididymis of the hamster and rat were incubated with [5-(3)H]uridine and glucose. By using a procedure avoiding bacterial and other cellular contamination, sonic extracts were prepared and digested with deoxyribonuclease and Pronase. Radioactive RNA of high molecular weight was isolated by two methods: (a) gel filtration on Sephadex G-75 columns and (b) polyacrylamide-gel electrophoresis in which it migrated in the region of 28S and 23S RNA markers. The macromolecules were alkali-labile and hydrolysed by ribonuclease. From (3)H radioactivity and E(260) of the isolated RNA the rate of incorporation of uridine into RNA of spermatozoa was calculated to be 0.1-0.5nmol/h per mg of RNA.
 ...
PMID:Ribonucleic acid synthesis by spermatozoa from the rat and hamster. 474 26

1. Highly purified mitochondria containing 3.0mug of RNA/mg of mitochondrial protein were prepared from rat liver by differential centrifugation. 2. RNA, labelled with [(32)P]P(i) or [(3)H]orotate, was isolated from these mitochondria by a phenol extraction method. The RNA sedimented at 15S and 13S on sucrose density gradients. Its nucleotide composition was 23% uridylate, 30% adenylate, 22% guanylate and 25% cytidylate. 3. RNA from mouse L cells was labelled with [(3)H]-uridine in the presence of 0.1mug of actinomycin D/ml to suppress the synthesis of cytoplasmic rRNA. The RNA isolated from crude L-cell mitochondria by a cold-phenol-sodium dodecyl sulphate method had components sedimenting at 15S and 12.5S. These components had an electrophoretic mobility on agarose-acrylamide gels of 21 and 12S(E) compared with 28 and 18S(E) for cytoplasmic rRNA. The nucleotide composition was 26% uridylate, 34% adenylate, 18% guanylate and 22% cytidylate. 4. RNA extracted from crude L-cell mitochondria by a hotphenol-sodium dodecyl sulphate method had an additional component sedimenting at 21S and having an electrophoretic mobility of 18S(E). It was probably DNA because of its sensitivity to deoxyribonuclease and its insensitivity to ribonuclease and alkali. It was present in nuclear fragments contaminating the crude mitochondrial fraction and could be removed by deoxyribonuclease or isopycnic-gradient centrifugation.
 ...
PMID:Ribosomal-type ribonucleic acid from rodent mitochondria. 549 58

1. The 105000g supernatant fraction of rat liver catalyses the incorporation of ribonucleotides from ribonucleoside triphosphates into polyribonucleotide material. The reaction requires Mg(2+) ions and is enhanced by the addition of an ATP-generating system and RNA, ATP, UTP and CTP but not GTP are utilized in this reaction. In the case of UTP, the product is predominantly a homopolymer containing 2-3 uridine residues, and there is evidence that these may be added to the 3'-hydroxyl ends of RNA or oligoribonucleotide primers. 2. The microsome fraction of rat liver incorporates ribonucleotides from ATP, GTP, CTP and UTP into polyribonucleotide material. This reaction requires Mg(2+) ions and is enhanced slightly by the addition of an ATP-generating system, and by RNA but not DNA. Supplementation of the reaction mixture with the three complementary ribonucleoside 5'-triphosphates greatly increases the utilization of a single labelled ribonucleoside 5'-triphosphate. The optimum pH is in the range 7.0-8.5, and the reaction is strongly inhibited by inorganic pyrophosphate and to a much smaller degree by inorganic orthophosphate. It is not inhibited by actinomycin D or by deoxyribonuclease. In experiments with [(32)P]UTP in the absence of ATP, GTP and CTP, 80-90% of (32)P was recovered in UMP-2' or -3' after alkaline hydrolysis of the reaction product. When the reaction mixture was supplemented with ATP, GTP and CTP, however, about 40% of the (32)P was recovered in nucleotides other than UMP-2' or -3'. Although the reactions seem to lead predominantly to the synthesis of homopolymers, the possibility of some formation of some heteropolymer is not completely excluded.
 ...
PMID:Chain extension of ribonucleic acid by enzymes from rat liver cytoplasm. 568 1

Infection of human embryonic kidney (HEK) cell cultures with adenovirus types 2 or 12 resulted in an initial drop in the rate of incorporation of (3)H-thymidine into deoxyribonucleic acid (DNA) during the early latent period of virus growth, followed by a marked rise in label uptake. It was shown by cesium chloride isopycnic centrifugation that, after adenovirus 2 infection, there was a decrease in the rate of incorporation of thymidine into cellular DNA. Moreover, DNA-DNA hybridization experiments revealed that, by 28 to 32 hr after infection with either adenovirus 2 or 12, the amount of isolated pulse-labeled DNA capable of hybridizing with HEK cell DNA was reduced by approximately 60 to 70%. Autoradiographic measurements showed that the inhibition of cellular DNA synthesis was due to a decrease in the ability of an infected cell to synthesize DNA. The adenovirus-induced inhibition of host cell DNA synthesis was not due to degradation of cellular DNA. (3)H-thymidine incorporated into cellular DNA at the time of infection remained acid-precipitable, and labeled material was not incorporated into viral DNA. Furthermore, when zone sedimentation through neutral or alkaline sucrose density gradients was employed, no detectable change was observed in the sedimentation rate of this cellular DNA at various times after infection with adenovirus 2 or 12. In addition, there was no increase in deoxyribonuclease activity in cells infected with either virus. Cultures infected for 38 hr with adenovirus 2 or 12 incorporated three to four times as much (3)H-uridine into ribonucleic acid (RNA) as did non-infected cultures. Furthermore, the net RNA synthesized by infected cultures substantially exceeded that of control cultures. The activity of thymidine kinase was induced, but there was no stimulation of uridine kinase.
 ...
PMID:Kinetics of nucleic acid synthesis in human embryonic kidney cultures infected with adenovirus 2 or 12: inhibition of cellular deoxyribonucleic acid synthesis. 580 81

Preparations of purified and disrupted suspensions of Coxiella burnetii are able to incorporate ribonucleotides into polymers in the presence of adenosine, guanosine, cytidine, and uridine triphosphates. Nucleotide incorporation requires the presence of all four ribonucleoside triphosphates. The reaction is enhanced by the addition of phosphoenolpyruvate and pyruvic kinase, and exogenous deoxyribonucleic acid, and is inhibited by deoxyribonuclease and actinomycin D. Incorporation is maximal between pH 7.0 and 8.0, and at 37 C. The synthesized polymer is relatively insensitive to deoxyribonuclease and is sensitive to ribonuclease and dilute alkaline hydrolysis. The data indicate the presence of an autonomous deoxyribonucleic acid-dependent ribonucleic acid polymerase in the rickettsial agent.
 ...
PMID:Physiology of rickettsiae. VI. Host-independent synthesis of polyribonucleotides by Coxiella burnetii. 602 13

Treponema pallidum (Nichols strain), extracted in medium containing Eagle minimal essential medium 50% fresh, heat-inactivated normal rabbit serum, and 1.0 mM dithiothreitol, was incubated under 3% oxygen in the presence of tritiated nucleic acid precursors. [8-3H]adenine was incorporated with high efficiency into trichloroacetic acid-insoluble material; 2'-deoxyadenosine and uridine were incorporated in lower quantities, and thymine and thymidine were not incorporated. Incorporation of [3H]adenine was inhibited by penicillin G, mitomycin C, actinomycin D, and erythromycin, but was not affected by cycloheximide. Partial purification of nucleic acids from T. pallidum incubated with [8-3H]adenine for 36 to 72 h and subsequent treatment with ribonuclease and deoxyribonuclease revealed that 15 to 20% of the trichloroacetic acid-precipitable counts were resistant to ribonuclease but susceptible to deoxyribonuclease. A simple assay was developed in which NaOH treatment was used to distinguish incorporation into ribonucleic acid and deoxyribonucleic acid. Both ribonucleic acid and deoxyribonucleic acid synthesis continued for 6 days of incubation under 3% O2, whereas incorporation was limited to the first day of incubation in samples incubated under aerobic or anaerobic conditions. T. pallidum thus appears to be capable of significant de novo deoxyribonucleic acid and ribonucleic acid synthesis under microaerobic conditions.
 ...
PMID:Long-term incorporation of tritiated adenine into deoxyribonucleic acid and ribonucleic acid by Treponema pallidum (Nichols strain). 615 24


1 2 Next >>