Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.21.1 (DNase)
 7,655 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Highly purified, (32)P-labeled type 5 adenovirus was employed to study "uncoating" of viral deoxyribonucleic acid (DNA)-defined as the development of sensitivity to deoxyribonuclease. Viral infectivity and radioactivity adsorbed to KB cells at the same rate, and significant amounts of (32)P did not elute from cells throughout the eclipse period. Kinetic studies of viral penetration, eclipse of infectivity, and uncoating of viral DNA indicated that the three events were closely related temporally, that the rates of each were similar, and that they were completed within 60 to 90 min after infection. Viral penetration, eclipse, and uncoating proceeded normally under conditions which blocked protein synthesis, but they did not occur at 0 to 4 C. Neither viral DNA nor viral protein was degraded to acid-soluble material during the eclipse period. The nature of adenovirus DNA was studied after it was converted intracellularly from deoxyribonuclease-resistant to deoxyribonuclease-susceptible. Intact virions centrifuged in sucrose gradients had a sedimentation coefficient of approximately 800, and viral DNA sedimented as a particle of about 30S. Infection of KB cells with purified (32)P-labeled virus yielded deoxyribonuclease-susceptible viral nucleic acid which was in particles with sedimentation coefficients of 350 to 450S, i.e., greater than 10 times faster than DNA obtained from purified virions which had been disrupted by exposure to pH 10.5. When the DNA from disrupted virions was mixed with cell lysates, its sedimentation characteristics were essentially unchanged by the presence of cellular material.
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PMID:Intracellular uncoating of type 5 adenovirus deoxyribonucleic acid. 562 82

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.
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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

Infection with Leishmania tropica, a strain specific to the sandfly Phlebotomus papatasi, was inhibited in sandflies fed on turkey blood. Reduction of the parasite number was correlated with the digestive process. A relatively high DNAase level was induced in the gut of the sandfly by the nucleated turkey erythrocytes. This is the first record of vector-pathogen incompatibility, thus induced, and of differentially triggered digestive processes.
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PMID:Vector compatibility of Phlebotomus papatasi dependent on differentially induced digestion. 613 55

A fragment of the E. coli chromosome including the recC gene has been cloned by in vitro recombinant DNA techniques into a phage lambda vector to give the recombinant phage lambda drecC. This was used to derive the phage lambda drecBC by in vivo recombination. On lysogenisation of recB and recC mutants with lambda drecBC wild levels of UV-resistance and RecBC DNase activity were restored. Infection of E coli with lambda drecBC led to the synthesis of phage-coded proteins of 125 kilodaltons (kd) and 135 kd that were not synthesised on infection with the original lambda vector, whereas a 125 kd protein but not a 135 kd protein was synthesised in similar experiments with lambda drecC. The recombinant phages, which are unable to form plaques, presumably due to the deletion of essential phage genes during their construction, provided useful starting points from which to subclone the recB, recC, and the neighbouring thyA and argA genes individually into multiple copy plasmid vectors.
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PMID:Construction of recombinant lambda phages that carry the E. coli recB and recC genes. 621 90

Empty capsids of polyoma virus interact with DNA in a cell-free system to form polyoma-like particles (PLP). The DNA in these particles is protected from the action of pancreatic deoxyribonuclease. Transfer of genetic information by PLP has been accomplished by using a restriction fragment containing the transforming sequences of polyoma DNA as a model gene. Infection of rat F111 cells by PLP containing these sequences results in DNA-mediated cellular transformation. Gene transfer by PLP is 50 to 150 times more efficient than by the calcium phosphate precipitation method.
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PMID:Gene transfer by polyoma-like particles assembled in a cell-free system. 630 Oct 16

In a double-blind controlled study we compared the effectiveness of cephalexin b.i.d. versus q.i.d. in the treatment of group A streptococcal pharyngitis in 65 children. Clinical improvement was noted in 64 patients (98%) and bacteriologic cure in 60 (92%). Despite good compliance, three bacteriologic failures were noted in the q.i.d., and two in the b.i.d. treatment groups. Two of these five were carriers. Significant antibody responses were observed in 61% of the patients by at least one of three tests (ASO, anti-DNase B, Streptozyme). We also investigated the extended microbiology of streptococcal pharyngitis by looking for the presence of viruses, chlamydia and beta-lactamase producing organisms in the pharynx. Respiratory viruses were isolated concomitantly with Streptococcus pyogenes in six patients. Beta-lactamase producing bacteria were present in the pharynx of 98% of the patients at the initiation of treatment and comprised 1-98% of the total bacterial flora. The beta-lactamase producing flora did not significantly change with cephalexin therapy.
Infection
PMID:The extended microbiology of group A streptococcal pharyngitis. Observations during a double-blind controlled study of cephalexin twice versus four-times daily. 638 14

Infection of Alteromonas espejiana at restrictive temperature with mutant ts1 of bacteriophage PM2 resulted in the intracellular accumulation of virus-sized empty-appearing membrane vesicles. The DNA associated with purified vesicles was fully susceptible to digestion with DNase. Sedimentation analysis and electron microscopy suggested a full-length linear form of the normally circular viral genome. A pulse-chase-shift experiment suggested that [3H]thymidine-labeled DNA made under restrictive conditions is assembled into virions after shift to permissive temperature. A defective structural protein in the ts1 virion appears to be the cause of a rapid rate of thermal inactivation of infectivity. Analysis of the proteins of ts1 by isoelectric focusing indicated a more alkaline isoelectric mobility of the major capsid protein, sp27. Six spontaneous revertants of ts1 showed reversion to the wild-type isoelectric form of sp27. These results identify sp27 as the defective gene product of ts1. Taken together, these results suggest that the membrane of PM2 is formed without the aid of an inner core or an outer scaffolding.
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PMID:Mutant ts1 of bacteriophage PM2 is defective in the major capsid protein and fails to package its DNA. 682 14

Infection of 25- to 30-week-old SJL/J mice with the lactate dehydrogenase (LDH) virus resulted in a transitory T-cell lymphocytopenia. However, in 40- to 45-week-old animals, the initial lymphocytopenia was followed by persistent elevations in the peripheral leukocyte counts (B and T lymphocytes). Studies indicated that this difference had its basis in a plasma factor, termed lymphocyte proliferating factor (LPF), which was induced by infection of older SJL/J mice with the LDH virus. Further experimentation revealed that plasma LPF was sensitive to storage at -60 degrees C, to heating at 90 degrees C, and to treatment with DNase. These results suggested an identification of LPF as DNA. This possibility was supported by the demonstration of LPF activity in association with DNA extracts (blood, spleen and lymph nodes from LDH virus-infected mice) which was inactivated by DNase.
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PMID:Detection and characterization of a lymphocyte proliferating factor (LPF) in plasma of SJL/J mice infected with the LDH virus. 698 Jun 38

Recombinant human deoxyribonuclease I (DNase I) is an important clinical agent that is inhaled into the airways where it degrades DNA to lower molecular weight fragments, thus reducing the viscoelasticity of sputum and improving the lung function of cystic fibrosis patients. To investigate DNases with potentially improved properties, we constructed a molecular fusion of human DNase I with the hinge and Fc region of human IgG1 heavy chain, creating a DNase I-Fc fusion protein. Infection of Sf9 insect cells with recombinant baculovirus resulted in the expression and secretion of the DNase I-Fc fusion protein. The fusion protein was purified from the culture medium using protein A affinity chromatography followed by desalting by gel filtration and was characterized by amino-terminal sequence, amino acid composition, and a variety of enzyme-linked immunosorbent assays (ELISA) and activity assays. The purified fusion contains DNase I, as determined by a DNase I ELISA and an actin-binding ELISA, and an intact antibody Fc region, which was quantified by an Fc ELISA, in a 2:1 stoichiometric ratio, respectively. The dimeric DNase I-Fc fusion was functionally active in enzymatic DNA digestion assays, albeit about 10-fold less than monomeric DNase I. Cleavage of the DNase I-Fc fusion by papain resulted in a specific activity comparable to the monomeric enzyme. Salt was inhibitory for wild type monomeric DNase I but actually enhanced the activity of the dimeric DNase I-Fc fusion. The DNase I-Fc fusion protein was also less Ca2+-dependent than DNase I itself. These results are consistent with a higher affinity of the dimeric fusion protein to DNA than monomeric DNase I. The engineered DNase I-Fc fusion protein described herein has properties that may have clinical benefits.
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PMID:Expression and characterization of a DNase I-Fc fusion enzyme. 1009 62

The freshwater prawn Macrobrachium rosenbergii was experimentally infected with white spot syndrome virus (WSSV) by intramuscular injection. Infection was confirmed by positive, single-step, WSSV polymerase chain reaction (PCR) assays targeting the VP28 gene from Day 2 up to Day 90 post injection (p.i.). Although no mortality of WSSV-infected prawns was observed, bioassays with the black tiger shrimp Penaeus monodon using hemolymph from Day 90 PCR-positive prawns resulted in white spot disease (WSD). Transcriptional analysis of the VP28 gene of WSSV by reverse transcriptase (RT)-PCR assays and Western blot assays revealed transient expression of the VP28-specific transcript in DNase-treated total RNA from hemolymph, gills, head soft tissue and eyestalks at 2 d p.i. By 3 d p.i., the VP28 transcript could no longer be detected in eyestalks and hemolymph but was still lightly detectable in head soft tissue and gills. It became undetectable there from 5 d p.i. onwards, despite the undiminished presence of the virus shown by single-step PCR targeting of the VP28 gene. VP28 was not detected by the less sensitive Western blot in hemolymph at any time during the study period, but it was detectable in all other tested tissues from Days 2 to 4 p.i. Our results demonstrated that M. rosenbergii is tolerant to a relatively constant level of persistent WSSV infection characterized by a low expression of VP28 and, possibly, other virion proteins. Despite this, M. rosenbergii can carry a level of infectious WSSV sufficient to represent a feasible threat to cultivated penaeid shrimp such as P. monodon. It remains to be seen whether a very low virion protein expression relative to the viral copy number may constitute a general decapod characteristic for persistent viral infections that produce no signs of disease.
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PMID:Tolerance to white spot syndrome virus (WSSV) in the freshwater prawn Macrobrachium rosenbergii is associated with low VP28 envelope protein expression. 1733 Jul 38


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