Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: 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)

Apoptosis - programmed death of a cell - is a natural mechanism that controls the number of cells in an organism. Neoplastic cells as many types of normal cells, may be the subject of spontaneous apoptosis as well as they may be induced by anti-neoplastic factors. Neoplastic cells' resistance to drugs is often correlated with impossible induction of apoptosis in those cells. Though the process of apoptosis is not fully explained, a possible involvement of many genes in regulation of this process is indicated. One of them is bcl-2 gene and its product - bcl-2 protein, which has the property of apoptosis process inhibition and stimulation of a cell towards outliving (survival). Increased expression of bcl-2 gene is present in many neoplastic cells and it suggests a possible pathogenic role of bcl-2 gene in oncogenesis. In this paper the expression of bcl-2 gene in the cells of papilloma in larynx is defined in six children operated in the Department of Paediatric Otolaryngology of Medical School in Lublin. Papillomas of larynx are neoplasm's of particular resistance to treatment. Complete, cellular RNA was isolated with Chomczynski and Sacchi method using guanidine thiocyanate. Gene expression was defined with the method of reverse transcription by cDNA synthesis and amplification of bcl-2 gene fragment with specific oligonucleotides in reverse transcriptase polymerase chain reaction (RT-PCR). The products were identified on agarose gel. Expression of bcl-2 gene in the investigated cells of laryngeal papilloma was confirmed in all the children. The presence of bcl-2 gene product in these cells may be the cause of apoptosis inhibition and stimulation of cells proliferation of the neoplasm.
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PMID:Evaluation of bcl-2 gene expression in papilloma of larynx in children. 1086 21

This study describes the rapid detection of polioviruses in environmental waters by a simple reverse transcriptase-polymerase chain reaction (RT-PCR) using two primer pairs for differentiation of poliovirus from non-polio enteroviruses in a single reaction by a one-step method, combining RT and PCR in a single tube. The detection by agarose gel electrophoresis yielded 2 bands of 153-bp and 293-bp for poliovirus tested without the need for further hybridization. The detection sensitivity of this one-step duplex RT-PCR, as measured with RNA extracted by heat treatment from supernatant of infected cell extracts, was 10(-1) 50% tissue culture effective doses (TCID50). This assay was used to evaluate the ability of sample concentration by membrane filter-based adsorption and elution, and purification by a simple RNA isolation based on guanidine isothiocyanate-phenol-chloroform extraction; the system yielded a detection limit of 5 x 10(-1) TCID50 seeded in 5 liters of tap water. This protocol was applied to the poliovirus detection in environmental water collected from 2 communities in Bangkok, Thailand during February and May 1998. Of 100 samples tested, 2 water samples collected from the same open sewage pipeline at one location were positive for polioviruses and one sample collected from another sewage pipeline was positive for non-polio enterovirus while a further 97 water samples were negative for both polioviruses and non-polio enteroviruses. With poliovirus detection by cell culture technique, none of the 100 samples tested was positive for poliovirus type 1, 2 or 3. RT-PCR was more sensitive, rapid, simple and cost-effective than the cell culture technique since the two water samples which were positive for polioviruses by RT-PCR failed to be detected by cell culture. Sequence data of 293-bp amplicons from positive samples were compared with those of reference poliovirus strains in the Genbank and the EMBL databases and identity to the sequence of type 1 strain Sabin was found to be 99%.
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PMID:Rapid detection of polioviruses in environmental water samples by one-step duplex RT-PCR. 1102 64

The hallmark feature of abdominal aortic aneurysm (AAA) is the progressive degeneration of aortic wall. Matrix proteoglycans (PGs) play important roles in the development of vascular diseases and the function of the tissue. In this study, we examined the concentration, expression and localization of the small extracellular matrix PG biglycan and decorin. The concentration of small PGs present in normal and aneurysmal aortas was determined by biochemical methods following extraction of the tissues with guanidine hydrochloride and treatment with collagenase/elastase, isolation by ion-exchange and gel chromatographies and identification by Western blotting. The levels of mRNA encoding for biglycan and decorin were evaluated in corresponding tissue samples by reverse transcriptase polymerase chain reaction (RT-PCR). Distribution of extracellular matrix macromolecules was examined using Movat's pentachrome staining and localization of biglycan and decorin by immunohistochemistry. Both normal and aneurysmal aortas contained almost equal amounts of decorin (1.13+/-0.08 and 1.22+/-0.10 mg uronic acid per g of dry defatted (dd) tissue, respectively). Furthermore, the expression of decorin was almost constant in both tissues. In normal specimens decorin accounts for 22% of total PGs, whereas in AAA ones for 60%, due to the significant loss of other matrix PGs. In contrast, the concentration of biglycan was markedly decreased in aneurysmal aortas (57%, 0.478+/-0.04 mg uronic acid per g of dd tissue) in comparison to normal ones (1.12+/-0.10 mg uronic acid per g of dd tissue). Biglycan accounts for 22% of total PGs in normal aortas and 25% of total in aneurysmal tissue. A similar decrease (60%) in the amounts of mRNA encoding for biglycan was observed in the AAA. Immunohistochemical study showed that all aortic layers of AAA were characterized by a significant loss of elastin, biglycan and other PGs/GAGs and replacement of these molecules with collagen fibrils and decorin. The obtained data suggest that the altered matrix architecture of aorta, i.e. the differential expression of biglycan and localization of decorin may well be crucial parameters accounting for the functional degeneration of the tissue and the development of aneurysmal dilatation.
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PMID:Decreased biglycan expression and differential decorin localization in human abdominal aortic aneurysms. 1241 72

A potential safety concern in biotechnology purification schemes that employ re-use of column media, often for large numbers of chromatography runs, is loss of the virus removal capacity of the chromatographic purification operation over time. To define chromatography performance attributes that best predict retrovirus clearance during extended re-use of protein A media, small-scale protein A columns were cycled 150 to 460 times using concentrates of murine hybridoma cell culture supernatants, standard low pH elution buffers and different cleaning solutions (6 M urea, 6 M guanidine, 100 mM NaOH or 500 mM NaOH). Load, flow-through and eluate samples were taken periodically and assayed for reverse transcriptase (RT, an enzyme component of retroviruses) activity, bovine IgG (a component of the culture media), genomic DNA, leached protein A, and mouse IgG. Under all cleaning conditions tested, the log,10 reduction value (LRV) of RT activity did not decrease and impurity co-elution did not increase during the 150 to 460 purification/cleaning cycles. In the two studies in which the columns were cleaned with NaOH, the chromatography performance attribute that best predicted the column media lifespan was column capacity, as measured by antibody (Ab) step yield and breakthrough. In both studies, Ab capture decayed in a biphasic manner starting at cycle 200 (100 mM NaOH) or cycle 50 (500 mM NaOH). For media cycled 300+ times using 6 M urea or 6 M guanidine cleaning buffers, column performance, including RT activity LRV, was more stable, although small upward trends in Ab breakthrough were evident. In summary, our studies identify Ab step yield and breakthrough as performance attributes that decay prior to retrovirus LRV when protein A media is multiply-cycled. Thus, we propose that virus removal validation studies should be performed on new media only and these attributes can be monitored during protein A unit operations in lieu of performing virus removal validation studies with cycled protein A media.
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PMID:Identification of protein A media performance attributes that can be monitored as surrogates for retrovirus clearance during extended re-use. 1264 Dec 91

To permit rapid and efficient detection of Sabin poliovirus type 3 from human fecal samples, we developed a guanidine thiocyanate (GuSCN) extraction and reverse transcriptase polymerase chain reaction (RT-PCR) method. Using 10-fold serial dilutions from stock Sabin-Leon 12 a1b poliovirus type 3 at 10(7) TCID(50) per 0.1 ml, genome was detected to a dilution of 10(3) TCID(50) per 0.1 ml. A total of 40 archived fecal samples were examined using this GuSCN extraction method followed by RT-PCR. Fourteen of 20 poliovirus type 3 tissue culture-positive specimens (70%) and two of 20 tissue culture-negative specimens (10%) were detected by GuSCN extraction and RT-PCR. All positive and negative extraction and RT-PCR controls were identified accurately. This GuSCN extraction and RT-PCR technique is rapid, inexpensive, and can be readily adapted to identify genome sequences of other enterovirus types in large numbers of fecal samples. Moreover, the GuSCN technique extracts viral RNA directly from fecal samples, allowing observation of in vivo alterations of genome sequences. Further studies are underway to examine the development of revertant point mutations in the Sabin poliovirus type 3 genome following oral administration of trivalent Sabin Oral Poliovirus Vaccine to humans.
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PMID:Direct extraction of Sabin poliovirus genomes from human fecal samples using a guanidine thiocyanate extraction method. 1279 48

Nucleic acid sequence based amplification (NASBA) is an isothermal nucleic acid amplification procedure based on target-specific primers and probes, and the co-ordinated activity of 3 enzymes: AMV reverse transcriptase, RNase H, and T7 RNA polymerase. We have developed a real-time NASBA procedure for detection of piscine nodaviruses, which have emerged as major pathogens of marine fish. Viral RNA was isolated by guanidine thiocyanate lysis followed by purification on silica particles. Primers were designed to target sequences in the nodavirus capsid protein gene, yielding an amplification product of 120 nucleotides. Amplification products were detected in real-time with a molecular beacon (FAM labelled/methyl-red quenched) that recognised an internal region of the target amplicon. Amplification and detection were performed at 41 degrees C for 90 min in a Corbett Research Rotorgene. Based on the detection of cell culture-derived nodavirus, and a synthetic RNA target, the real-time NASBA procedure was approximately 100-fold more sensitive than single-tube RT-PCR. When used to test a panel of 37 clinical samples (negative, n = 18; positive, n = 19), the real-time NASBA assay correctly identified all 18 negative and 19 positive samples. In comparison, the RT-PCR procedure identified all 18 negative samples, but only 16 of the positive samples. These results suggest that real-time NASBA may represent a sensitive and specific diagnostic procedure for piscine nodaviruses.
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PMID:Detection of piscine nodaviruses by real-time nucleic acid sequence based amplification (NASBA). 1521 74

The effects of imipenem and meropenem on the transcriptional expression of resistance-related genes oprD, oprM and oprN in Pseudomonas aeruginosa were studied by quantitative real-time PCR. Four strains were examined: the type strain PT5 (PAO1), its derivatives M7 and PT149, and a clinical isolate, PaKT3. The derivative M7 is a nalB mutant, overexpressing the MexAB-OprM pump, and the derivative PT149 is a nfxC-type mutant, overexpressing the MexEF-OprN pump while it is down-regulated for the OprD protein. After 18 h incubation in broth, the cultures were divided into three portions. Two were supplemented with antibiotics and the other was left antibiotic-free as the control. After a further 45 min incubation, total RNA was isolated from the strains by guanidine denaturation and acid-phenol/chloroform extraction. DNA-free total RNAs were immediately reverse-transcribed by MMuLV reverse transcriptase. Concentrations of mRNAs obtained by quantitative PCR were expressed relative to uninduced portions of the strains. The results showed that oprD was relatively stable against carbapenem antibiotics. oprM was induced significantly by imipenem in only one strain and oprN was induced by imipenem in most of the strains. The responses at the mRNA level found here were unexpected and suggested a chaotic, unpredictable regulatory mechanism.
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PMID:Effect of carbapenems on the transcriptional expression of the oprD, oprM and oprN genes in Pseudomonas aeruginosa. 1531

Surveillance for avian influenza A viruses in wild bird populations is often limited by requirements for a cold chain from time of specimen collection, by availability of ultra-low temperature specimen storage within a few hours or days, and by laborious classical virologic procedures. Successful storage of specimens in preservatives at ambient temperature and subsequent detection of RNA by reverse transcriptase-polymerase chain reaction (RT-PCR) would assist in helping influenza surveillance efforts become more widespread in remote areas, as well as more timely and inexpensive. Here, we describe bird feces spiked with influenza A virus preserved with guanidine and commercial buffers or alcohols at ambient temperature and analyzed by RT-PCR protocols. Virus-specific RT-PCR products of, at most, 206 bp were recovered for samples preserved with alcohols and up to 521 bp for samples preserved with guanidine or commercial buffers. These results suggest that this approach is feasible in the field and that preserved specimens might be better assayed molecularly when preserved in guanidine or commercial buffers.
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PMID:Effect of preservative on recoverable RT-PCR amplicon length from influenza A virus in bird feces. 1825 9

Inhibitor resistance of several commercial Moloney murine leukemia virus reverse transcriptase (MMLV RT) enzymes was investigated. IC(50) values were determined for potential RNA contaminants, including guanidine thiocyanate, ethanol, formamide, ethylenediaminetetraacetic acid (EDTA), and plant-related acidic polysaccharides. Sensitivity (as judged by MMLV RT IC(50) values) was directly correlated to the outcome of "mock" reverse transcription-quantitative polymerase chain reaction (RT-qPCR) assays carried out with exogenous inhibitors. MMLV RT enzymes lacking RNase H activity were shown to be more sensitive to RT-qPCR inhibitors. In contrast, a thermal-resistant MMLV RT pentuple mutant (E69K/E302R/W313F/L435G/N454K) showed higher tolerance to these substances than the wild type. Increased resistance was also noted in RT-qPCR comparisons employing crude cell lysates.
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PMID:Mutant of Moloney murine leukemia virus reverse transcriptase exhibits higher resistance to common RT-qPCR inhibitors. 2010 Apr 52

INTRODUCTIONCtenophores, or comb jellies, are a group of marine animals whose unique biological features and phylogenetic placement make them a key taxon for understanding animal evolution. Some characteristics are present in nearly all ctenophores, including biradial symmetry, comb rows composed of linked cilia, an apical sensory organ, and two tentacles bearing specialized adhesive cells. All ctenophores studied thus far have the same stereotyped cleavage program and go through a specific stage of development known as the cydippid larva, after which adult structures develop and diverge greatly among species; this is particularly useful for comparative studies. In some cases, gene expression patterns appear to be conserved. Of particular interest is the finding that some genes are expressed in regions of the ctenophore body that are not morphologically distinct from the adjacent areas. However, it has proven difficult to determine the orthology of some genes, possibly because of the extreme divergence of ctenophore representatives. This protocol describes how to isolate total RNA from ctenophore embryos and larvae. After the specimens are sorted, cleaned, and concentrated, they are placed into TRI Reagent, a solution containing phenol and guanidine thiocyanate that allows for the effective isolation of total RNA. The resulting RNA can be used for various applications (e.g., to generate cDNA for reverse transcriptase-polymerase chain reactions). Although the protocol focuses on embryonic and larval samples, the technique can also be applied to adult tissues.
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PMID:Ctenophore tissue preparation and extraction of RNA. 2135 29


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