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:2.6.1.1 (aspartate aminotransferase)
21,665 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The pathway construction for biosynthesis of aromatic amino acids in Escherichia coli is atypical of the phylogenetic subdivision of gram-negative bacteria to which it belongs (R. A. Jensen, Mol. Biol. Evol. 2:92-108, 1985). Related organisms possess second pathways to phenylalanine and tyrosine which depend upon the expression of a monofunctional chorismate mutase (CM-F) and cyclohexadienyl dehydratase (CDT). Some enteric bacteria, unlike E. coli, possess either CM-F or CDT. These essentially cryptic remnants of an ancestral pathway can be a latent source of biochemical potential under certain conditions. As one example of advantageous biochemical potential, the presence of CM-F in Salmonella typhimurium increases the capacity for prephenate accumulation in a tyrA auxotroph. We report the finding that a significant fraction of the latter prephenate is transaminated to L-arogenate. The tyrA19 mutant is now the organism of choice for isolation of L-arogenate, uncomplicated by the presence of other cyclohexadienyl products coaccumulated by a Neurospora crassa mutant that had previously served as the prime biological source of L-arogenate. Prephenate aminotransferase activity was not conferred by a discrete enzyme, but rather was found to be synonymous with the combined activities of aspartate aminotransferase (aspC), aromatic aminotransferase (tyrB), and branched-chain aminotransferase (ilvE). This conclusion was confirmed by results obtained with combinations of aspC-, tyrB-, and ilvE-deficient mutations in E. coli. An example of disadvantageous biochemical potential is the presence of a cryptic CDT in Klebsiella pneumoniae, where a mutant carrying multiple enzyme blocks is the standard organism used for accumulation and isolation of chorismate.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Remnants of an ancient pathway to L-phenylalanine and L-tyrosine in enteric bacteria: evolutionary implications and biotechnological impact. 208 22

An open clinical study of ofloxacin in respiratory tract infections was conducted with patients receiving daily doses of ofloxacin 300 mg, 400 mg or 600 mg. The duration of treatment was 6 to 14 days for 70% of the patients. Ofloxacin was effective in 668 of 828 patients analysed (80.7%). Of 293 patients with upper respiratory infections, the efficacy rate was 85.3%. In 535 cases with lower respiratory infections, ofloxacin was effective in 78.1%. It is noteworthy that a 70% efficacy rate was obtained in 80 cases with intractable chronic diffuse panbronchiolitis primarily associated with Pseudomonas aeruginosa. There was no difference in the efficacy rate among various daily doses or severity of infections. In lower respiratory infections the bacterial eradication rate was 80.9% for Gram-positive aerobes (including 80% for Staphylococcus aureus and 76.5% for Streptococcus pneumoniae) and 72.1% for Gram-negative aerobes (including 92.6% for Klebsiella pneumoniae, 32.3% for P. aeruginosa and 97.1% for Haemophilus influenzae). Although there were no serious cases, adverse reactions were noted in 46 of 843 patients (5.5%): 38 cases (4.5%) of gastrointestinal tract reactions (nausea, vomiting, heartburn, etc.), 4 cases (0.5%) of hypersensitivity (e.g. eruption) and 19 (2.3%) of central nervous system effects (e.g. dizziness). Abnormal changes in laboratory findings included elevations of AST (1.2%) and ALT (1.5%) and an increase in the eosinophil count (1.7%).
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PMID:Ofloxacin in respiratory tract infection. A review of the results of clinical trials in Japan. 332 61

A total of 466 patients were treated with cefoperazone. The drug was usually administered by drip infusion of 2 to 4 gm/day. Therapy was described as markedly effective and moderately effective in 64 of 77 patients (83.1%) treated for urinary tract infections; 253 of 316 patients (80.1%) treated for respiratory infections; 37 of 48 patients (77.1%) treated for liver biliary duct infections; ten of 16 patients (62.5%) treated for septicemia; and seven of nine patients (77.8%) being treated for other infections. Overall, cefoperazone was effective 79.6% of all patients treated. With respect to bacteriological activity, the overall eradication rate for gram-negative organisms (including Pseudomonas aeruginosa, Klebsiella sp, Escherichia coli, Haemophilus influenzae, Enterobacter sp, and Proteus sp) was 81% (182/225) and for gram-positive (Staphyloccocus aureus, Streptococcus pneumoniae and Streptococcus faecalis) 90% (36/40). Of 205 patients who failed to respond to previous antibiotic therapy, 67.8% were treated effectively with cefoperazone. Side effects, such as skin eruption, pyrexia and diarrhea, occurred in only 4.8% of patients treated, while laboratory abnormalities, such as elevated glutamic-oxaloacetic transaminase, glutamic-pyruvic transaminase, alkaline phosphatase, and eosinophil values, occurred in only 6.4% of the treated patients. None of these abnormal values were of clinical significance.
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PMID:Clinical trials with cefoperazone in the field of internal medicine in Japan. 644 92

We describe the complete purification of aromatic aminotransferase I, the enzyme responsible for the ability of Klebsiella aerogenes to use tryptophan and phenylalanine as sole sources of nitrogen, as well as the partial purification of aromatic aminotransferase IV. An examination of the properties of these enzymes revealed that aminotransferase I had much greater affinity for the aromatic amino acids than aminotransferase IV, explaining the essential role of aminotransferase I in the utilization of exogenously supplied aromatic amino acids. The properties of aminotransferase IV suggest that this enzyme is actually an aspartate aminotransferase (EC 2.6.1.1), corresponding to the product of the aspC gene of Escherichia coli.
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PMID:Purification and properties of aromatic amino acid aminotransferase from Klebsiella aerogenes. 700 15

In Rhizobium meliloti, an aspartate aminotransferase (AspAT) encoded within a 7.3-kb HindIII fragment was previously shown to be required for symbiotic nitrogen fixation and aspartate catabolism (V. K. Rastogi and R.J. Watson, J. Bacteriol. 173:2879-2887, 1991). A gene coding for an aromatic aminotransferase located within an 11-kb HindIII fragment was found to complement the AspAT deficiency when overexpressed. The genes encoding these two aminotransferases, designated aatA and tatA, respectively, have been localized by subcloning and transposon Tn5 mutagenesis. Sequencing of the tatA gene revealed that it encodes a protein homologous to an Escherichia coli aromatic aminotransferase and most of the known AspAT enzymes. However, sequencing of the aatA gene region revealed two overlapping open reading frames, neither of which encoded an enzyme with homology to the typical AspATs. Polymerase chain reaction was used to selectively generate one of the candidate sequences for subcloning. The cloned fragment complemented the original nitrogen fixation and aspartate catabolism defects and was shown to encode an AspAT with the expected properties. Sequence analysis showed that the aatA protein has homology to AspATs from two thermophilic bacteria and the eukaryotic tyrosine aminotransferases. These aminotransferases form a distinct class in which only 13 amino acids are conserved in comparison with the well-known AspAT family. DNA homologous to the aatA gene was found to be present in Agrobacterium tumefaciens and other rhizobia but not in Klebsiella pneumoniae or E. coli.
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PMID:Cloning and nucleotide sequencing of Rhizobium meliloti aminotransferase genes: an aspartate aminotransferase required for symbiotic nitrogen fixation is atypical. 809 10

Ninety-seven cases of pyogenic liver abscesses in a 4-yr period were studied: 27.8% (27 cases) were associated with biliary tract stone, 5.2% (five cases) were associated with biliary tract cancer, and there were two cases of diabetes (2.1%) associated with anal infection, but 63.9% (63 cases) were diagnosed as cryptogenic. Forty patients (64.5%) in the cryptogenic group had diabetes mellitus, and 23 of them (23/40, 57.5%) had gas-forming infection. All patients received parenteral antibiotics therapy, percutaneous aspiration, drainage, or operation. The overall mortality was 16.5%. Diabetes mellitus alone, without demonstrable infectious foci, was an important predisposing factor for pyogenic liver infection. Furthermore, to evaluate the clinical importance of gas-forming pyogenic liver infections, we separated these 42 diabetic patients into gas-forming and non-gas-forming groups, after sonography and CT scan. Klebsiella pneumoniae was the major pathogen in both groups. There was no significant difference in the clinical manifestations, complication, bacterial culture, or laboratory data between these two groups, except that the AST level was higher in the gas-forming group. However, the gas-forming group had higher mortality rate (30.4% vs. 5.3%). Gas-forming liver abscesses were common among the diabetics. Early and adequate drainage for pyogenic liver abscesses with parenteral antibiotics are crucial in their management.
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PMID:Pyogenic liver abscess in Taiwan: emphasis on gas-forming liver abscess in diabetics. 823 41

An optimized multilocus enzyme electrophoresis method, which involves polyacrylamide-agarose gel electrophoresis followed by electrophoretic transfers on nitrocellulose sheets, was developed for the analysis of enzyme polymorphism in several aerobic and anaerobic bacterial species including Staphylococcus aureus, Streptococcus pneumoniae, S. agalactiae, Klebsiella pneumoniae and K. oxytoca, Clostridium bifermentans and C. sordellii, and Prevotella bivia. Serial electrophoretic transfers (during 5-15 min each) from a single polyacrylamide gel could be achieved for most enzymes studied, and allowed an increased definition of enzyme bands on nitrocellulose as compared to migration gels. Four enzymes, which could not be blotted in such conditions, could still be stained in gels after blotting. Thus, the method allowed the combined analysis of several enzymes after a single gel electrophoresis separation. The analysis of enzyme polymorphism in the various species studied raised the interest of polymorphic loci such as esterase or glutamic-oxaloacetic transaminase for epidemiologic studies. The method characterized a genetic diversity of enzyme loci of S. pneumoniae higher than previously reported, and is thus convenient for the analysis of genetic relationships between related isolates. Since the present method reduces the tediousness of multilocus enzyme electrophoresis and requires experimental conditions that are not specific for the bacterial population studied, it may be proposed for rapid population genetics analysis of a wide variety of bacteria.
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PMID:Multilocus enzyme analysis in aerobic and anaerobic bacteria using gel electrophoresis-nitrocellulose blotting. 1075 43

Although cells of the innate inflammatory response, such as macrophages and neutrophils, have been extensively studied in the arena of Gram-negative bacterial pneumonia, a role for T cells remains unknown. To study the role of specific T cell populations in bacterial pneumonia, mice deleted of their TCR beta- and/or delta-chain were intratracheally inoculated with Klebsiella pneumoniae. Gamma delta T cell knockout mice displayed increased mortality at both early and late time points. In contrast, mice specifically lacking only alpha beta-T cells were no more susceptible than wild-type mice. Pulmonary bacterial clearance in gamma delta-T cell knockout mice was unimpaired. Interestingly, these mice displayed increased peripheral blood dissemination. Rapid up-regulation of IFN-gamma and TNF-alpha gene expression, critical during bacterial infections, was markedly impaired in lung and liver tissue from gamma delta-T cell-deficient mice 24 h postinfection. The increased peripheral blood bacterial dissemination correlated with impaired hepatic bacterial clearance following pulmonary infection and increased hepatic injury as measured by plasma aspartate aminotransferase activity. Combined, these data suggest that mice lacking gamma delta-T cells have an impaired ability to resolve disseminated bacterial infections subsequent to the initial pulmonary infection. These data indicate that gamma delta-T cells comprise a critical component of the acute inflammatory response toward extracellular Gram-negative bacterial infections and are vital for the early production of the proinflammatory cytokines IFN-gamma and TNF-alpha.
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PMID:Gamma delta-T cells are critical for survival and early proinflammatory cytokine gene expression during murine Klebsiella pneumonia. 1094 93

Fasciolosis is recognized as an important human disease. Wistar rats experimentally infected with Fasciola hepatica were examined using data obtained in the advanced chronic state of the disease (200, 300 and 400 days post-infection, dpi). Pigment stones (PS) and bile specimens were collected. The same procedure was applied in control rats. Liver tests were determined using stored serum samples. Bacteriological bile culture revealed viable bacteria (Escherichia coli, 45% of cases, Enterococcus faecalis, 45% and Klebsiella pneumoniae, 10%). The presence of bacterobilia was associated with liver serum enzymes, including aspartate aminotransferase (AST or SGOT), alanine aminotransferase (ALT or SGPT), alkaline phosphatase (AP) and total bilirubin levels. Multivariate analysis suggested an association between bacterobilia and the following factors: duration of parasitic infection and intensity of parasitic infection supported the impression that the obstruction caused by advanced chronic fasciolosis in the rat may be related to biliary sepsis. Extrapolation to human infection in fasciolosis hyperendemic areas is discussed. In conclusion, the results of the rodent model should lead to a reconsideration of treatment features in human disease, i.e. therapeutic strategies should not only include a parasitic treatment but also consider the possibility of bacterial co-infection.
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PMID:High risk of bacterobilia in advanced experimental chronic fasciolosis. 1706 56

Complete medical evaluations were performed on 25 wild black lemurs (Eulemur macaco macaco) in Lokobe Reserve, northwestern Madagascar. Each animal received a complete physical examination. Weight, body temperature, heart rate, and respiratory rate were recorded. Blood samples were collected for complete blood cell count, differential white blood cell count, hemoparasite examination, serum biochemical profile, fat-soluble vitamin analysis, trace mineral analysis, and Toxoplasma gondii and viral serology. Fecal samples were collected for bacterial culture and endoparasite examination. Ectoparasites were collected and identified. Values were compared to established ranges from captive black lemurs in North American zoos. Significant differences exist between captive and wild animals for total white blood cell count, segmented neutrophil count, band neutrophil count, eosinophil count, monocyte count, and basophil count, and for serum biochemistry values of aspartate aminotransferase, alanine aminotransferase, total bilirubin, serum alkaline phosphatase, total protein, creatinine, phosphorus, calcium, sodium, potassium, and creatine phosphokinase. One animal had a positive Toxoplasma titer. Detected endoparasites were identified as Lemuricola and Callistroura. Two ectoparasite mites were identified, one within the Psoroptes genus and one within the Laelapidae family. Enteric bacterial flora included Enterococcus sp., Staphylococcus sp., Escherichia coli, Streptococcus sp., Klebsiella ozaenae and Bacillus cereus.
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PMID:Biomedical evaluation of black lemurs (Eulemur macaco macaco) in Lokobe Reserve, Madagascar. 1746 78


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