Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:2.7.7.49 (reverse transcriptase)
 31,746 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Several antitumor substances that effectively inhibited the growth of ascites and solid tumor cells transplanted in mice were isolated from pine cone NaOH extract by acid- and ethanol-precipitation. These antitumor substances were also potent antiviral agents against human immunodeficiency virus, herpes simplex virus and influenza virus; they induced antimicrobial activity against Staphylococcal aureus, Escherichia coli, Pseudomonas aeruginosa, Klebsiella pneumoniae and Candida albicans, and induced antiparasite activity against Hymenolepis nana in mice. Chemical analysis of these substances by IR, UV, NMR, ESR and partition chromatography on cellulose-TLC plate disclosed that they had lignin-related structures complexed with sugars or polysaccharides. Chlorinated decomposition of the lignin portion significantly reduced their antiviral activity. In agreement with this, the antiviral activity of synthesized lignins prepared by polymerization of phenylpropanoid precursors was comparable to that of the undecomposed counterparts of the pine cone extract. Acid hydrolysis of the polysaccharide portion significantly reduced the ability of the substances to induce antitumor and antimicrobial activities in mice. With an appropriate eliciting agent, intravenous administration of natural lignified substances transiently induced endogenous production of a cytotoxic factor (possibly tumor necrosis factor) in normal mice. Their priming activity was significantly higher than that of their component units or degradation products. These data suggest the importance of conjugating lignins with polysaccharides for in vivo expression of various kinds of immunopotentiating activity. As possible explanations for their induction of a variety of immunopotentiating activities, these natural and synthetic lignins stimulated macrophage NBT-reducing activity, polymorphonuclear cell (PMN) iodination and splenocyte DNA synthesis and inhibited poly (ADP-ribose) glycohydrolase, RNA-dependent DNA polymerase (reverse transcriptase) and RNA-dependent RNA polymerase activities.
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PMID:Antitumor, antiviral and immunopotentiating activities of pine cone extracts: potential medicinal efficacy of natural and synthetic lignin-related materials (review). 164 35

We have previously described a recombinant protein, designated CD4(178)-PE40, consisting of the human immunodeficiency virus (HIV) envelope glycoprotein-binding region of human CD4 linked to the translocation and ADP-ribosylation domains of Pseudomonas aeruginosa exotoxin A. By virtue of its affinity for gp120 (the external subunit of the HIV envelope glycoprotein), the hybrid toxin selectively binds to and kills HIV-1-infected human T cells expressing surface envelope glycoprotein and also inhibits HIV-1 spread in mixed cultures of infected and uninfected cells. We now report that CD4(178)-PE40 and reverse transcriptase inhibitors exert highly synergistic effects against HIV-1 spread in cultured human primary T cells. Furthermore, combination treatment can completely eliminate infectious HIV-1 from cultures of human T-cell lines. This conclusion is based on protection of a susceptible cell population from HIV-induced killing, complete inhibition of virus protein accumulation, and elimination of HIV DNA (as judged by quantitative polymerase chain reaction analysis). The results highlight the therapeutic potential of treatment regimens involving combination of a virostatic drug that inhibits virus replication plus an agent that selectively kills HIV-infected cells.
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PMID:Elimination of infectious human immunodeficiency virus from human T-cell cultures by synergistic action of CD4-Pseudomonas exotoxin and reverse transcriptase inhibitors. 170 Oct 55

Glutamine depletion strongly inhibits the replication of Rauscher murine leukaemia retrovirus (RLV) in vitro. Pseudomonas 7A glutaminase-asparaginase (PGA), capable of depleting glutamine and asparagine for prolonged periods, was used to determine the therapeutic effectiveness of glutamine depletion in mice infected with RLV or Friend virus. During PGA treatment of viraemic animals, serum reverse transcriptase activity fell to control levels and infected animals did not develop splenomegaly. The therapeutic results obtained with PGA compared favourably with those of azidothymidine given intraperitoneally at 30 mg/kg/day. Western blots performed on splenic tissue from control and treated animals indicated that glutamine depletion prevented readthrough of an amber codon at the gag-pol junction, stopping translation of viral mRNA at that point. Treatment of RLV-infected animals with PGA resulted in nearly a 200% increase in mean survival time even when therapy was initiated late in the course of the disease. To our knowledge, this is the first demonstration that a nutrient required for viral replication can be enzymically depleted in vivo to inhibit viral replication.
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PMID:Inhibition of mouse retroviral disease by bioactive glutaminase-asparaginase. 170 10

The primary structures of 16S rRNAs of Bartonella bacilliformis, an isolate of the cat scratch disease (CSD) bacillus, and a strain phenotypically similar to the CSD bacillus were determined by reverse transcriptase sequencing. These microorganisms were found to be members of the alpha-2 subgroup of the class Proteobacteria. The sequence from B. bacilliformis was most closely related to the rRNA of Rochalimaea quintana (91.7% homology), the etiologic agent of trench fever. The sequence from the isolate of the CSD bacillus showed the greatest homology with Brucella abortus (89.7%) and, when compared with oligonucleotide catalog data, formed a cluster with Rhodopseudomonas palustris, Pseudomonas carboxidovorans, Nitrobacter species, and Bradyrhizobium species. The 16S rRNA sequence was also determined for the Cleveland Clinic isolate, which was previously shown to be phenotypically similar to and approximately 30% related, by DNA hybridization, to the CSD bacillus. The Cleveland Clinic isolate was isolated from a patient not diagnosed with CSD. The rRNAs from these bacteria exhibited 98.2% homology, confirming that this isolate is a second species in the same genus as the CSD bacillus. Our data suggest that neither B. bacilliformis nor the CSD bacillus is the etiologic agent of bacillary epithelioid angiomatosis.
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PMID:16S rRNA sequences of Bartonella bacilliformis and cat scratch disease bacillus reveal phylogenetic relationships with the alpha-2 subgroup of the class Proteobacteria. 171 21

A regulatory mutation (alg52) in a Pseudomonas aeruginosa alginate-negative mutant (strain 8882) is complemented efficiently by the gene algR2 and somewhat inefficiently by a second gene termed algR3. algR3 and algR2 are located on a 4.4-kilobase-pair HindIII-BamHI fragment, which has been completely sequenced. algR2 has previously been characterized. Introduction of kanamycin-resistance cassettes and deletion-subcloning experiments involving various open reading frames in the HindIII-BamHI fragment have localized the algR3 gene, which encodes a 340-amino acid polypeptide. This highly basic regulatory protein contains 17% lysine and 36% alanine. The predicted amino acid sequence shows no significant similarity with any bacterial proteins and yet is highly similar to the sea urchin Lytechinus pictus histone H1 subtype of protein. Promoter localization by reverse transcriptase mapping of the algR3 gene shows the presence of Escherichia coli sigma 70 recognition sequences, and coupled transcription/translation experiments in E. coli demonstrate the presence of a 39-kDa polypeptide encoded by the cloned algR3 gene.
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PMID:AlgR3, a protein resembling eukaryotic histone H1, regulates alginate synthesis in Pseudomonas aeruginosa. 210 18

The nucleotide sequence of the 1206 bp fragment of Pseudomonas aeruginosa DNA coding for the recA gene has been determined. This structure was shown to contain an open reading frame corresponding to a protein with m.w. 36808 D highly homologous (70%) to the Escherichia coli recA protein. Homology on the DNA level is significantly lower (57%) due to the high G/C content characteristics of Pseudomonas DNA. Making use of S1 nuclease and reverse transcriptase it was shown that in P. aeruginosa and E. coli cells recAPA gene transcription starts from A or T unit. Unlike "-35" region, "-10" region is homologous to the consensus E. coli promoter sequence. Comparison of primary structures of the recAPA and recAEC proteins demonstrates that the recAPA protein is by 7 amino acid residues shorter and differs from recAEC at 108 positions. Homology is the lowest in the C-terminal part. Basing on the analysis of hybrid recAPA proteins with a modified C-terminal part, it may be suggested that C-terminus is nonessential for main activities of the recA protein.
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PMID:[Structure of the Pseudomonas aeruginosa recA gene]. 212 86

The regulatory gene xylS on the TOL plasmid of Pseudomonas putida activates the transcription of the xylDLEGF operon for the m-toluate-degrading pathway in the presence of m-toluate. The gene also activates the transcription of the same operon in the presence of m-xylene or m-methylbenzyl alcohol, but for this activation another regulatory gene, xylR, is required. In this study we examined the xylS expression by determining the mRNA by reverse transcriptase mapping and by monitoring the enzyme activity of the xylE gene product, which was expressed under the control of the xylS promoter. The results of the above experiments provide evidence that xylR positively controls the transcription of xylS in the presence of m-xylene or m-methylbenzyl alcohol. The xylS product thus amplified may in turn activate the xylDLEGF operon. The nucleotide sequence of the xylS promoter resembles that of the promoter of the xylCAB operon for the m-xylene-degrading pathway, which is also activated by xylR in the presence of m-xylene or m-methylbenzyl alcohol. In addition, we have demonstrated that the expression of xylR is negatively controlled by its own product. On the basis of these findings, we propose a revised model for the regulation of expression of xyl genes on the TOL plasmid.
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PMID:Expression of the regulatory gene xylS on the TOL plasmid is positively controlled by the xylR gene product. 244 45

The catB and catC genes encode cis,cis-muconate lactonizing enzyme I (EC 5.5.1.1) and muconolactone isomerase (EC 5.3.3.4), respectively. These enzymes are required for the dissimilation of benzoate to beta-ketoadipate by Pseudomonas putida and are under coordinate transcriptional regulation. By deletion analysis and the use of pKT240 as a promoter probe vector, we located a single promoter region for the catBC operon upstream of catB. RNA-DNA hybridization studies, together with reverse transcriptase mapping, demonstrated that this promoter must be activated in the presence of an inducer molecule for effective transcription of the operon. In addition, the transcription initiation site was located 64 base pairs upstream of the catB initiation codon, and sequences upstream of -43 were required for promoter function. The catBC promoter was compared with other positively regulated procaryotic promoters to identify possible consensus sequences.
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PMID:Transcriptional regulation, nucleotide sequence, and localization of the promoter of the catBC operon in Pseudomonas putida. 244 20

The xylR gene is a regulatory gene on the TOL plasmid, which acts in a positive manner on xyl operons for degradation of toluene and xylenes in Pseudomonas putida. A DNA fragment containing the xylR promoter region was cloned on promoter-probing vectors, and its nucleotide sequence was determined. The transcription initiation site of the xylR gene was determined in cells of P. putida and Escherichia coli by S1 nuclease and reverse transcriptase mapping. Two initiation sites were detected which were identical in both P. putida and E. coli. The amounts of mRNA synthesized in both bacterial cells were almost the same and independent of the inducers for xyl operons. The consensus sequences for E. coli promoters were found in the region preceding the respective transcription initiation sites. The product of the xylR gene was identified by the maxicell system as a protein with an approximate molecular weight of 67,000.
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PMID:Determination of the transcription initiation site and identification of the protein product of the regulatory gene xylR for xyl operons on the TOL plasmid. 299 47

A DNA segment that promotes gene expression in Pseudomonas putida was identified in pTN8, a mutant plasmid of an RP4-TOL recombinant. A promoter on the segment was cloned with a promoter-probe vector containing the xylE gene of the TOL plasmid. The xylE gene was expressed under the control of the promoter, and the gene product catechol 2,3-dioxygenase was constitutively synthesized. As analyzed by an S1 nuclease protection assay, the amount of mRNA produced in P. putida was more than that in Escherichia coli. Fine S1 nuclease mapping and reverse transcriptase mapping revealed three tandem transcription start sites in both P. putida and E. coli. The nucleotide sequence preceding the transcription start sites was determined; a part of this sequence contained a sequence homologous to E. coli promoter sequences. A tentative consensus sequence for P. putida constitutive promoters is proposed.
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PMID:Nucleotide sequence of a DNA segment promoting transcription in Pseudomonas putida. 301 41


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