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:2.7.7.7 (DNA polymerase)
17,007 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

This report describes a DNA amplification procedure for routine identification of heat-labile-toxin-producing Escherichia coli. Two oligonucleotide primers were used in a polymerase chain reaction procedure to amplify a highly conserved region of the A subunit of the heat-labile enterotoxin gene. Amplifications were done directly on E. coli colonies from plates when Salmonella, Shigella, or parasite infections were excluded as agents of the severe diarrhea in the patients. The conditions for the polymerase chain reaction method were empirically determined, and the procedure is inexpensive, sensitive, and specific. Positive results can be obtained over a wide variation in bacterial numbers, with no inhibition of Thermus aquaticus DNA polymerase. Detection of the amplified product can be done by agarose gel electrophoresis, which is specific and sensitive enough for routine diagnosis of this pathogen in clinical isolates. If greater sensitivity and specificity are required, hybridization with 32P- or alkaline phosphatase-labeled oligonucleotide probes can be used. Our results suggest that heat-labile-toxin-producing E. coli is responsible for about 9% of nondiagnosed diarrhea cases in Tygerberg Hospital, Tygerberg, Republic of South Africa.
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PMID:Improved method for the routine identification of toxigenic Escherichia coli by DNA amplification of a conserved region of the heat-labile toxin A subunit. 199 50

Twenty four Esch. coli isolates obtained from patients of diarrhoea were tested by DNA hybridization for presence of enterotoxigenic Esch. coli (ETEC). The probe generated for this study was labelled by two different ways using the large Klenow fragment of DNA polymerase-I. It was observed that labelling by sequential harnessing of the exonuclease and polymerase activity of the enzyme was superior to extension of random hexanucleotide primers. This method besides being economic, dispenses with the critical step involved in the thermodynamics of oligoannealing and initiation of DNA synthesis.
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PMID:Comparative evaluation of labelling intensity for detection of enterotoxigenic Escherichia coli. 816 96

An assay based on reverse transcription coupled with the polymerase chain reaction (RT-PCR) was used for the detection of hog cholera virus (HCV) and bovine virus diarrhoea virus (BVDV) in cell culture. In this study, a precipitate of the supernatants derived from cell cultures infected with HCV and BVDV was used in RT reactions, in place of extracted viral RNA. Both RT and PCR were performed using recombinant Thermus thermophilus (rTth) DNA polymerase. The specificity of the RT-PCR products was confirmed by hybridisation with a digoxygenin-labelled DNA probe. The results not only show that the stage of RNA isolation can be bypassed, but also illustrate an easy and efficient means of obtaining templates suitable for identification and characterisation of HCV and BVDV in tissue culture by RT-PCR.
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PMID:Reverse transcription combined with polymerase chain reaction as a detection method for pestiviral infections. 859 11

A specific serotype, O3:K6, of Vibrio parahaemolyticus has recently been causing epidemics of gastroenteritis in Southeast Asia, Japan, and North America. To examine whether the new O3:K6 strains possess characteristics that may exacerbate outbreaks, we compared V. parahaemolyticus O3:K6 strains with non-O3:K6 strains using strains isolated from individuals with traveler's diarrhea at Kansai Airport Quarantine Station, Osaka, Japan. All 24 O3:K6 strains possessed a common plasmid, pO3K6 (DNA size, 8,782 bp, with 10 open reading frames [ORFs]). The gene organization of pO3K6 was similar to that of Vf33, a filamentous phage previously described in V. parahaemolyticus. We isolated a phage (phage f237) from the culture supernatant of V. parahaemolyticus O3:K6 strain KXV237, which formed a turbid plaque on an indicator strain. The genome of f237 was single-stranded DNA, and the double-stranded DNA obtained by treatment of the genome with DNA polymerase was identical to that of pO3K6 when analyzed by agarose gel electrophoresis after HindIII digestion. Furthermore, the N-terminal amino acid sequence of the f237 major coat protein was found in ORF4 of pO3K6. Our results showed that pO3K6 is a replicative form of f237. Among the ORFs found in the f237 genome, the sequence of ORF8 had no significant homology to those of any proteins in databases. ORF8 was located on a region corresponding to the distinctive region of Vf33, and its G+C content was apparently lower than that of the remaining DNA sequence of f237. By colony hybridization, ORF8 was detected only in O3:K6 strains isolated since 1996 and was not found in O3:K6 strains isolated before 1996 and clinical V. parahaemolyticus strains other than those of serotype O3:K6. Thus, this study shows that f237 is exclusively associated with recent V. parahaemolyticus O3:K6 strains. The ORF8 gene can be a useful genetic marker for the identification of the recently widespread O3:K6 strains of V. parahaemolyticus.
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PMID:A filamentous phage associated with recent pandemic Vibrio parahaemolyticus O3:K6 strains. 1083 69

Acute human immunodeficiency virus (HIV) seroconversion illness is a difficult diagnosis to make because of its nonspecific and protean manifestations. We present such a case in an adolescent. A 15-year-old boy presented with a 5-day history of fever, sore throat, vomiting, and diarrhea. The patient also reported a nonproductive cough, coryza, and fatigue. The patient's only risk factor for HIV infection was a history of unprotected intercourse with 5 girls. Physical examination was significant for fever, exudative tonsillopharyngitis, shotty cervical lymphadenopathy, and palpable purpura on both feet. Laboratory studies demonstrated lymphopenia and mild thrombocytopenia. Hemoglobin, serum creatinine, and urinalysis were normal. The following day, the patient remained febrile. Physical examination revealed oral ulcerations, conjunctivitis, and erythematous papules on the thorax; the purpura was unchanged. Serologies for hepatitis B, syphilis, HIV, and Epstein-Barr virus were negative. Bacterial cultures of blood and stool and viral cultures of throat and conjunctiva showed no pathogens. Coagulation profile and liver enzymes were normal. Within 1 week, all symptoms had resolved. The platelet count normalized. Repeat HIV serology was positive, as was HIV DNA polymerase chain reaction. Subsequent HIV viral load was 350 000, and the CD4 lymphocyte count was 351/mm3. HIV is the seventh leading cause of death among people aged 15 to 24 in the United States, and up to half of all new infections occur in adolescents. Our patient presented with many of the typical signs and symptoms of acute HIV infection: fever, fatigue, rash, pharyngitis, lymphadenopathy, oral ulcers, emesis, and diarrhea. Other symptoms commonly reported include headache, myalgias, arthralgias, aseptic meningitis, peripheral neuropathy, thrush, weight loss, night sweats, and genital ulcers. Common seroconversion laboratory findings include leukopenia, thrombocytopenia, and elevated transaminases. The suspicion of acute HIV illness should prompt virologic and serologic analysis. Initial serology is usually negative. Diagnosis therefore depends on direct detection of the virus, by assay of viral load (HIV RNA), DNA polymerase chain reaction, or p24 antigen. Both false-positive and false-negative results for these tests have been reported, further complicating early diagnosis. Pediatricians should play an active role in identifying HIV-infected patients. Our case, the first report of acute HIV illness in an adolescent, emphasizes that clinicians should consider acute HIV seroconversion in the appropriate setting. Recognition of acute HIV syndrome is especially important for improving prognosis and limiting transmission. It is imperative that we maintain a high index of suspicion as primary care physicians for adolescents who present with a viral syndrome and appropriate risk factors.
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PMID:Acute human immunodeficiency virus syndrome in an adolescent. 1452 19

About 130 kb of sequence information was obtained from the coliphage JS98 isolated from the stool of a pediatric diarrhea patient in Bangladesh. The DNA shared up to 81% base pair identity with phage T4. The most conserved regions between JS98 and T4 were the structural genes, but their degree of conservation was not uniform. The head genes showed the highest sequence conservation, followed by the tail, baseplate, and tail fiber genes. Many tail fiber genes shared only protein sequence identity. Except for the insertion of endonuclease genes in T4 and gene 24 duplication in JS98, the structural gene maps of the two phages were colinear. The receptor-recognizing tail fiber proteins gp37 and gp38 were only distantly related to T4, but shared up to 83% amino acid identity to other T6-like phages, suggesting lateral gene transfer. A greater degree of variability was seen between JS98 and T4 over DNA replication and DNA transaction genes. While most of these genes came in the same order and shared up to 76% protein sequence identity, a few rearrangements, insertions, and replacements of genes were observed. Many putative gene insertions in the DNA replication module of T4 were flanked by intron-related endonuclease genes, suggesting mobile DNA elements. A hotspot of genome diversification was located downstream of the DNA polymerase gene 43 and the DNA binding gene 32. Comparative genomics of 100-kb genome sequence revealed that T4-like phages diversify more by the accumulation of point mutations and occasional gene duplication events than by modular exchanges.
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PMID:Comparative genomics of the T4-Like Escherichia coli phage JS98: implications for the evolution of T4 phages. 1557 76

Microsporidia are ubiquitous obligate eukaryotic intracellular parasites that are now felt to be more akin to degenerate fungi than to protozoa. Microsporidia can be highly pathogenic, causing a broad range of symptoms in humans, especially individuals who are immunocompromised. The vast majority of human cases of microsporidiosis have been reported during the past 20 years, in patients with HIV/AIDS, while only relatively rare cases have been described in immunocompetent individuals. However, microsporidia infections are being increasingly reported in patients following solid-organ transplanation, where the main symptom has been diarrhea. The authors report the first case of pulmonary microsporidial infection in an allogeneic bone marrow transplant recipient in the United States and only the second case in the world. The patient, with a history of Hodgkin disease followed by acute myelogenous leukemia received a T-cell-depleted graft, but succumbed to respiratory failure 63 days post transplantation. An open lung biopsy, taken just before death, was originally thought to show toxoplasmosis. The correct diagnosis of microsporidiosis was made postmortem by light and electron microscopy. DNA polymerase chain reaction analysis confirmed the diagnosis and furthermore revealed it to be the dog strain of the microsporidia species Encephalitozoon cuniculi. Although to date rarely diagnosed, microsporidial infection should also be considered in the differential diagnosis of, e.g., unexplained pulmonary infection in bone marrow transplant patients.
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PMID:Fatal pulmonary microsporidiosis due to encephalitozoon cuniculi following allogeneic bone marrow transplantation for acute myelogenous leukemia. 1603 80

Clofarabine is a purine nucleoside analog that inhibits DNA synthesis and repair. Its effects are mediated via the inhibition of ribonucleotide reductase and DNA polymerase. Clofarabine also disrupts the integrity of mitochondrial membranes, resulting in programmed cell death. In 61 pediatric patients with relapsed or refractory acute lymphoblastic leukemia treated with clofarabine 52 mg/m2 infused intravenously over 2 hours once daily for 5 days every 2-6 weeks, rates of complete remission, complete remission without platelet recovery, and partial remission were 12%, 8%, and 10%, respectively. Data are from two non-comparative, multicenter, phase II studies. The most common adverse events associated with clofarabine 52 mg/m2 once daily for 5 days every 2-6 weeks in 96 patients with acute myelogenous or lymphoblastic leukemia (combined analysis of phase I/II trials) were hematologic events (including anemia, leukopenia, thrombocytopenia, neutropenia, and febrile neutro-penia), gastrointestinal events (including vomiting, nausea, and diarrhea), infections, and transient elevations in liver enzymes. Capillary leak syndrome or systemic inflammatory response syndrome was reported in four patients.
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PMID:Clofarabine: in pediatric patients with acute lymphoblastic leukemia. 1611 62

A 4-yr-old male bongo antelope (Tragelaphus euryceros) died after an acute clinical course involving a febrile illness, anorexia, lethargy, minor oculonasal discharge, and diarrhea. Histologic lesions were compatible with malignant catarrhal fever (MCF). Polymerase chain reaction (PCR) revealed an amplified region of a herpesviral DNA polymerase gene sequence nearly identical to that of a MCF virus previously identified in Nubian ibex (Capra nubiana). The bongo had been housed across from an exhibit containing Nubian ibex that tested positive for MCF viral antibodies by competitive inhibition enzyme-linked immunosorbent assay. Further testing of the zoo's ibex via PCR also revealed viral DNA sequences nearly identical to those found in the bongo's tissues.
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PMID:Ibex-associated malignant catarrhal fever in a bongo antelope (Tragelaphus euryceros). 1793 56

Zinc is an essential trace element for human nutrition that is an integral part of many enzyme systems, including DNA polymerase complex. Zinc deficiency has been associated with stunting of growth and sexual immaturity. In children, deficiency causes a fatal condition called acrodermatitis enteropathica. The same syndrome has been observed in patients on total parenteral nutrition (TPN) who do not receive zinc. In TPN the requirements have been estimated by balance studies to be 3 mg/d in patients without gastrointestinal losses and a mean of 12 mg/d in patients with diarrhea and fistula losses.
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PMID:Zinc: an essential trace element for parenteral nutrition. 1987 52


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