Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.6.1.1 (aspartate aminotransferase)
 21,665 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

It is shown by fluorescence spectroscopy that the post-activated form of neocarzinostatin chromophore (NCSi-glu) can form stable complexes with single-site oligonucleotides (SSOs) featuring sequences known to be involved in double stranded (AGC.GCT, AGT.ACT, AGA.TCT, ACA.TGT) or single stranded (AGG.CCT) cleavage (attacked residues in bold). Furthermore, the same SSOs form cleavage productive complexes with native neocarzinostatin chromophore (NCS chrom) over a similar concentration range. The productive complexes yield damage similar to that observed if the same sequence is part of a longer DNA piece. Previously identified double stranded site sequences ATT.AAT and TAT.ATA are shown to contain overlapping attack sites. Binding order preference derived from fluorescence quenching experiments for NCSi-glu is consistent with constants derived by quantitative cleavage affinity binding experiments with NCS chrom. This confirms the similarity in interactions between the NCSi-glu and NCS chrom and justifies the use of NCSi-glu as a stable analog of NCS chrom.
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PMID:Binding and cleavage characteristics of the complexes formed between the neocarzinostatin chromophore and single site containing oligonucleotides. 758 49

Phosphorylation of the region containing Thr-494, Thr-495 and Thr-497, present in the catalytic domain of protein kinase C alpha (PKC alpha), is a preliminary event necessary for subsequent PKC activation [Cazaubon and Parker (1993) J. Biol. Chem. 268, 17559-17563]. To define the essential residues in this region, various combinations of alanine substitutions for threonine residues 494, 495 and 497 have been tested. These mutations yielded expressed polypeptides of 76 and 80 kDa in ratios that vary from 100% 80 kDa (wild-type kinase, active) to 100% 76 kDa (AAA mutant, inactive) with the hierarchy being wild-type PKC alpha (TTT), ATT, AAT, TTA, ATA, TAA, AAA (the nomenclature indicates the location of alanine residues substituted for Thr-494, Thr-495 and Thr-497 respectively). Only the mutants retaining Thr-497 displayed kinase activity in vitro. The results overall indicate that Thr-497 plays the dominant role in the regulation of PKC alpha activity but that in the wild-type protein, Thr-495 may also be important. Consistent with the need for phosphorylation in this region, an intrinsically active PKC alpha could be produced in bacteria by exchanging Thr-495 for a glutamic acid residue.
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PMID:Threonine-497 is a critical site for permissive activation of protein kinase C alpha. 804 86

The 61 codons and the three terminators were counted in the coding sequences of 31 families of proteins of higher vertebrates. The protein families were ordered according to their evolutionary rate. In each family, the ratio between the Observed and Expected frequency of each codon was obtained (O/E ratio). A strong and significant positive correlation was observed between the O/E ratio of the eight codons AAC, TAT, ATA, GAA, ACA, AAT, ATG and CGA and the evolutionary rate of the protein. A negative and significant correlation was observed for codons AAG and GAG. It was advanced that the functional constraints of proteins can influence the usage of codons, particularly for those trimers which are components of signal sequences. It was also observed that the O/E ratios of the terminators are negatively correlated with the evolutionary rate of the protein they terminate, and the correlation is significant for TAA and TGA, which in vertebrates might be older than TAG.
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PMID:Codon usage and evolutionary rates of proteins. 815 18

Little is known about the presence of common medical pathogens in the human oral cavity. Using a 16S rRNA-based PCR identification method, this study determined the occurrence of Porphyromonas asaccharolytica, Bacteroides fragilis and Chlamydia pneumoniae in subgingival plaque from 50 adults with advanced periodontitis. Each patient contributed samples from 3 deep periodontal pockets collected by paper points. The PCR primers were for P. asaccharolytica 5'-CTC TAG CTA GAG TGT ACT GG-3' and 5'-ATA GGG TTT ATA GAT TAG CTC TCT-3', for B. fragilis 5'-AAT GAT TCC GCA TGG TTT CAT TA-3' and 5'-GCG GTG ATT GCT CAC TGA CA-3', and for C. pneumoniae 5'- TGA CAA CTG TAG AAA TAC AGC-3' and 5'-CGC CTC TCT CCT ATA AAT-3'. The primers yielded a single amplicon with the respective reference strains and produced no amplicon with colonies of 25 groups of oral organisms. None of the three test species were detected in any of the 50 pooled subgingival samples tested. P. asaccharyolytica, B. fragilis and C. pneumoniae do not seem to be part of the periodontopathic microbiota in humans.
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PMID:Absence of Porphyromonas asaccharolytica, Bacteroides fragilis and Chlamydia pneumoniae in human subgingival plaque. 957 14

Ethidium bromide (EB) and 4'-6-diamidino-2-phenylindole (DAPI) are both well-known fluorochromes for detecting DNA fragments. EB binds to DNA by intercalation and DAPI binds in the DNA minor groove. We previously developed a staining method using both EB and DAPI that is selective for AT-rich DNA fragments. Using this double-staining method, AT-rich DNA fragments are visualized as bluish-white fluorescent bands. To further characterize this method, a series of synthetic DNA fragments were designed with systematic variations in the length, AT content, and DNA sequence pattern. The staining properties of these fragments were determined in the presence of DAPI and EB, and the following results were obtained. (i) In a series of fragments with three AT base pairs followed by one GC base pair, the stained DNA fragments exhibited different fluorescent colors and varied from bluish (more DAPI staining) to pinkish (less DAPI staining) in the order 5'-AAA-3', 5'-AAT-3', 5'-ATA-3', 5'-TTA-3'. (ii) In fragments with constant AT content, the blue fluorescent color increased with increasing number of A (or T) nucleotides, due to increased DAPI binding. The blue color was saturated when the number of A (or T) nucleotides was 12 or greater. (iii) The fluorescent color of the stained DNA fragments changed in the order of red-orange, pink, pinkish-white, white, bluish-white, blue as the AT content increased from 0 to 100%. Thus, the fluorescent color of DNA fragments stained with DAPI and EB depends on base composition and nucleotide sequence, suggesting that individual stained DNA fragments may have characteristic and specific fluorescent colors. The fluorescent color emitted by specific stained DNA fragments in the presence of EB and DAPI can be analyzed with a high degree of sensitivity and resolution using the XYZ colorimetric system.
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PMID:Characterization of the selective staining of DNA on gels using two fluorochromes. 1076 71

The lizard Lacerta (Zootoca) vivipara, which is viviparous in the greatest part of its distribution range, has however some oviparous populations on the southern margin of its range. The present study aimed at determining the reproductive mode and the ATA (aspartate transaminase) enzyme characteristics of four populations in Slovenia and one population in Croatia. The Slovenian females studied here presented an oviparous reproductive mode which strongly resembled those observed in the oviparous populations of south-western France and north-western Spain. Our electrophoresis analyses revealed the existence of two distinct alleles, ATA-150 and ATA-200, in the oviparous populations of Slovenia. These alleles were identical to those observed in the French and Spanish oviparous group and were distinct from the allele ATA-100 characterizing the viviparous populations that we had previously studied. Although we did not study the reproductive mode of Croatian females, the allele ATA-200 observed in one population of Croatia strongly suggested that this population might also be oviparous.
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PMID:Further evidence of the existence of oviparous populations of Lacerta (Zootoca) vivipara in the NW of the Balkan Peninsula. 1087 94

It has previously been demonstrated that accumulated beta-catenin serves as an oncoprotein in synovial sarcoma and results in a poor overall survival rate, but the frequency of beta-catenin mutation was quite low (8.2%). The present study, using essentially the same study group of cases, screened for genetic alterations in the mutation cluster region (MCR) of the APC gene in 49 cases of synovial sarcoma. SSCP analysis followed by DNA direct sequencing revealed five missense APC mutations in four cases of synovial sarcoma (8.2%). The mutational sites comprised one case each at codons 1299 (GCT to ACT, Ala to Thr), 1412 (GGA to AGA, Gly to Arg), and 1414 (GTA to ATA, Val to Ile), in addition to one case with double point mutations at codon 1398 (AGT to AAT, Ser to Asn) and at codon 1413 (ATG to ATA, Met to Ile), together with beta-catenin mutation at codon 32 (GAC to TAC, Asp to Tyr). All four cases with APC mutations were histologically of the monophasic fibrous type and showed beta-catenin accumulation. All three cases with APC mutations available for follow-up data were long survivors. This study provides the first evidence that APC mutations also occur in the field of sarcoma, especially in synovial sarcoma.
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PMID:APC mutations in synovial sarcoma. 1192 Jul 41

Hyperbaric oxygen (HBO) therapy is an effective adjunct in treating ischemia-reperfusion (I/R) injury of brain, small intestine, testis, and crushing extremities. This study was designed to test the hypotheses that preconditioning the rats with HBO could protect the liver against subsequent I/R injury. Daily treatment with one-dose HBO (90 min, 2.5 ATA) was brought about for male Sprague Dawley rats for 1 to 3 days before an I/R injury of liver. Hepatic expression of heat-shock protein 70 (Hsp70), total concentration of glutathione (GSH), activity of catalase, superoxide dismutase (SOD), and serum AST and ALT were estimated before and after HBO, as well as after I/R injury. The results showed that activity of hepatic catalase was decreased by one dose, but not three doses, of HBO as compared with baseline data. However, hepatic Hsp70 expression fluctuated insignificantly. AST and ALT increase less in rats preconditioned with one-dose HBO as compared with those without HBO or with three-dose HBO. Our results showed preconditioning by one-dose HBO protects rat liver against subsequent ischemia-reperfusion injury.
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PMID:Preconditioned hyperbaric oxygenation protects the liver against ischemia-reperfusion injury in rats. 1596 20

Nowadays an increasing number of women are participating in recreational diving. A special recompression treatment table for delayed pulmonary barotrauma or decompression sickness was developed by V.V. Smolin in the Institute for Biomedical Problems (IBMP, Russia). The aim of our study was to investigate the effect of simulated dives (similar to this recompression treatment table) on biochemical parameters of healthy women. Three healthy female volunteers participated in long-term simulated diving to 8 ATA (0.8 MPa). Blood samples for determination of the biochemical substrate levels and activity of blood enzymes using a Reflotron analyzer were obtained at the control period, at the beginning of decompression and at the post dive period. No significant changes of serum levels of glucose, triglycerides, cholesterol, HDL cholesterol and urea were found during this experimental period or in comparison with the predive values. There were no significant changes in ALT activity in two volunteers but there was some tendency for an insignificant decrease in AST activity. One of the volunteers had a considerable increase in AST and ALT activities 15 h after the dive, probably due to a modified diet outside the experiment conditions. Thus, the long-term simulated diving recompression treatment table did not lead to a shift in the woman's serum biochemical status. However, it remains necessary to consider probable dysfunction of liver due to hyperbaric exposure.
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PMID:Blood biochemical parameters in women during long-term simulated hyperoxic diving up to 8 ATA. 1686 35

In a previous study, we obtained histologic documentation of liver gas embolism in the rat model of rapid decompression. The aim of the study was to assess in the same model occurrence and time course of liver embolism using 2-D ultrasound imaging, and to explore by this means putative liver gas embolism in recreational scuba divers. Following 42 min compression at 7 ATA breathing air and 12 min decompression, eight surviving female rats were anesthetized and the liver imaged by ultrasound at 20 min intervals up to 120 min. A significant enhancement of echo signal was recorded from 60 to 120 min as compared to earlier post-decompression times. Enzymatic markers of liver damage (AST, ALT, and GGT) increased significantly at 24 h upon decompression. Twelve healthy experienced divers were studied basally and at 15-min intervals up to 60 min following a 30-min scuba dive at 30 msw depth. At 30 min upon surfacing echo images showed significant signal enhancement that progressed and reached plateau at 45 and 60 min. Total bilirubin at 24 h increased significantly (p = 0.02) with respect to basal values although within the reference range. In conclusion, 2-D ultrasound liver imaging allowed detection of gas embolism in the rat and defined the time course of gas accumulation. Its application to scuba divers revealed liver gas accumulation in all subjects in the absence of clear-cut evidence of liver damage or of any symptom. The clinical significance of our findings remains to be investigated.
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PMID:Post-dive ultrasound detection of gas in the liver of rats and scuba divers. 2131 12


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