Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The concentration of free poly(C) in solution in the course of its interaction with poly(G) as well as in the presence of preformed complex poly(G).poly(C) was measured by differential pulse polarography (DPP) at a mercury dropping electrode. Poly(C) binding with poly(G) was shown to hamper its electrochemical interaction with the mercury electrode and registration by DPP. It was concluded that the extremely low DPP signal from poly(C) in the presence of preformed complex was the result of its interaction with the distortions in the secondary structure of complex molecules containing free guanines. For quantitative testing of these defects, measurement of Tb3+ ion fluorescence was applied. It was shown that preliminary denaturation of the poly(G) secondary structure reduced the amount of structural defects in the complex and restored of complete DPP registration of redundant poly(C) added to this complex. These results show that the combination of DPP and Tb3+ fluorescence measurements permits one to detect at the quantitative level the structural defects in the poly(G).poly(C) complex.
Mol Biol (Mosk)
PMID:[Analysis of defects in the structure of the complex poly(G).poly(C)]. 799 Aug 24

Preliminary investigations on the detection of nucleic acid hybridisation by direct electrochemical techniques are described. Initial experiments were performed with calf thymus DNA, while as a model system, plasmid DNA (pEMBL) which can be prepared in single stranded forms from each of two original double stranded plasmids (+19 and -19) was used. Electrochemical analyses have been performed using mercury pool, glassy carbon and screen printed carbon working electrodes.
Biochem Mol Biol Int 1994 Jan
PMID:An electrochemical method for detection of nucleic acid hybridisation. 801 87

Three different, independently isolated mercury-resistance-conferring plasmids, pMER327/419, pMER330 and pMER05, from cultures originating from the river Mersey (UK), contain identical regulatory merR genes and transposon ends. The mer determinant from pMER327/419 contains an additional potential ORF (ORF F) located between merP and merA when compared with the archetypal Tn501. Although these plasmids confer narrow-spectrum resistance (resistance to Hg2+, but not organomercurials) their merR genes encode a potential organomercurial-sensing protein. Transposition of the mer of pMER05 into plasmid RP4 was demonstrated and, as with Tn502 and Tn5053, insertion occurred at a specific region. The sequence of pMER05 is identical at the 'left' and 'right' termini and across merR to Tn5053, which was independently isolated from the chromosome of a Xanthomonas sp. bacteria from the Khaidarkan mercury mine in Kirgizia, former Soviet Union [Kholodii et al., J. Mol. Biol. 230 (1993a) 1103-1107]. The transpositional unit of pMER05 is, like that of Tn5053, bounded by DNA homologous to the imperfect 25-bp inverted repeats (IR) of the In2 integron, which brackets antibiotic-resistance cassettes in Tn21 subgroup transposons. At one end of the transposable element, and internal to the In2-like IR, is a 38-bp IR which closely resembles the IR that bounds Tn21.
 ...
PMID:The sequence of the mer operon of pMER327/419 and transposon ends of pMER327/419, 330 and 05. 806 7

Neutron activation analysis of 13 Mediterranean striped dolphins Stenella coeruleoalba showed high mercury and selenium contaminations of main tissues and organs of these cetaceans. The mercuric contents were excessive, particularly in liver (from 68 to 2272 micrograms/g dry wt. basis), then in kidney, lung, muscle, heart and brain. The selenium concentrations were also high in liver (from 45 to 1320 micrograms/g dry wt. basis), then in kidney, lung, muscle, skin and heart. The main way of contamination seems to be the food through trophic network, but skin and lung are also able to play a part which must be elucidated. The average Hg/Se ratios in liver and kidney were respectively 1.82 and 1.59. Linear relationship between mercury and selenium concentrations in tissues and organs, particularly in liver and kidney, were confirmed. The mercury and selenium interaction on a toxicological point of view was established by a statistical approach; in the same way, intervention of zinc, metallothioneins and glutathiones have been discussed.
Cell Mol Biol (Noisy-le-grand) 1993 Sep
PMID:Mercury, zinc and selenium bioaccumulation in tissues and organs of Mediterranean striped dolphins Stenella coeruleoalba meyen. Toxicological result of their interaction. 822 72

Microscopic observation, using physical development of silver, was carried out to localize the mercury-selenium interaction products in the organs of Mediterranean striped dolphins. The silver-metal reaction products were located mainly in hepatocytes and macrophages for liver, in proximal tubules for kidney. They were less abundant in lung than in liver and kidney. The result of semi-quantitative histochemistry tests showed that silver staining deposits were more abundant at relatively high metal concentrations than low metal contents, but independent of the metal contents. Comparisons with the most concentrated metal contents suggested that there might be a new complex of mercury and selenium, which could not be stainable by physical silver development.
Cell Mol Biol (Noisy-le-grand) 1993 Nov
PMID:Microscopic localization of mercury-selenium interaction products in liver, kidney, lung and brain of Mediterranean striped dolphins (Stenella Coeruleoalba) by silver enhancement kit. 826 61

We describe a novel type of mercury resistance transposon, Tn5053, which was found in the chromosome of a mercury-resistant Xanthomonas strain isolated from a mercury mine. An 8400 base-pair Tn5053 is bracketed by 25 base-pair inverted repeats that have no sequence homology with inverted repeats of classical mercury resistance transposons Tn501 and Tn21. Instead they show high homology with inverted repeats bracketing the antibiotic resistance segment of Tn21 (integron In2). A 38 base-pair element, which is highly homologous to the inverted repeats of classical mercury resistance transposons has been found within Tn5053 near one of its ends. This internal inverted repeat is fused to the mer operon of Tn5053 in exactly the same way as in the Tn501 mercury resistance transposon. This finding suggests that the mer operon was integrated into the Tn5053 transposition module not through integron-specific pathway but rather via insertion of a classical mercury resistance transposon.
J Mol Biol 1993 Apr 20
PMID:Tn5053, a mercury resistance transposon with integron's ends. 838 3

Human lymphocytes (HL) as well as lymphocytes (RL), hepatocytes (RH), and gastric mucosa cells (GM) of Sprague-Dawley rats were treated in vitro for 1 h with methylmercury chloride (MMC, 0.5-4 micrograms/ml) and dimethylmercury (DMM, 5-40 micrograms/ml). The cytotoxicity of the two organic mercury compounds was assessed by dye exclusion, and the extent of induced DNA fragmentation was measured with a single-cell microgel electrophoresis assay. Both MMC and DMM induced DNA damage and cytotoxicity in a dose-related manner in HL, RL, and GM. MMC was more effective in causing a significant increase in median DNA migration than DMM at doses yielding approximately the same degree of cytotoxicity. In rat hepatocytes the MMC-induced DNA damage was, however, lower than in the other cells. An analysis of repair kinetics following exposure to 2 micrograms/ml MMC was carried out in human lymphocytes obtained from an adult male donor. The bulk of DNA repair occurred 90 min after in vitro exposure, and it was about complete by 120 min following cessation of exposure. Finally, in order to have a basis for extrapolating to the human situation, in vivo studies were performed with Sprague-Dawley rats, also assessing the DNA damage and cytotoxicity in the lymphocytes and gastric mucosa cells. These in vivo results after oral exposure may be directly compared to the in vitro data obtained in the same cells.
Environ Mol Mutagen 1993
PMID:Comparative studies on cytotoxic and genotoxic effects of two organic mercury compounds in lymphocytes and gastric mucosa cells of Sprague-Dawley rats. 840 77

Effects of methyl methanesulfonate (MMS) on mouse testicular cell kinetics and sperm chromatin structure were determined flow cytometrically. Mice were exposed to a single ip injection of saline containing 0 or 150 mg/kg MMS. Relative ratios of 1N, 2N and 4N testicular cells were not affected until 22 days postexposure. Ratios of 1N cell types were altered from 13 to 22 days and were near normal by 25 days. This study revealed an MMS induced alteration of chromatin structure in testicular, elongated spermatids by the sperm chromatin structure assay (SCSA), a flow cytometric measure of the susceptibility of acridine orange stained sperm DNA to denaturation in situ. The SCSA also detected alterations in cauda sperm chromatin structure at 3 days, which was 8 days prior to alterations in sperm head morphology, indicating the increased sensitivity of the SCSA. SCSA data were practically similar whether measuring either fresh or frozen/thawed sperm, or whether measured by two different types of flow cytometers: a) laser driven, orthogonal optical axis; or b) low cost mercury arc lamp system with epiillumination. The data support the model of Sega and Owens [Mutat Res 111:227-244:1983] that MMS alkylates cysteine-SH groups in sperm protamines, thereby destabilizing sperm chromatin structure and leading to broken chromosomes and mutations.
Environ Mol Mutagen 1993
PMID:Effects of methyl methanesulfonate on mouse sperm chromatin structure and testicular cell kinetics. 844 43

Astacin, a 200 residue digestive zinc-endopeptidase from the crayfish Astacus astacus L., is the prototype of the "astacin family", which comprises several membrane-bound mammalian endopeptidases and developmentally implicated regulatory proteins. Large trigonal crystals of astacin were grown, and X-ray reflection data to 1.8 A resolution were collected. The astacin structure has been solved by multiple isomorphous replacement using six heavy-atom derivatives, and refined to a crystallographic R-value of 0.158 applying stringent constraints. All 200 residues are clearly defined by electron density; 181 solvent molecules have been localized. Besides the native structure, the structures of Hg-astacin (with a mercury ion replacing the zinc) and of the apoenzyme were also refined. The astacin molecule exhibits a kidney-like shape. It consists of an amino-terminal and a carboxy-terminal domain, with a deep active-site cleft in between. The zinc ion, located at the bottom of this cleft, is co-ordinated in a novel trigonal-bipyramidal geometry by three histidine residues, a tyrosine and by a water molecule, which is also bound to the carboxylate side-chain of Glu93. The amino-terminal domain of astacin consists mainly of two long alpha-helices, one centrally located and one more peripheral, and of a five-stranded pleated beta-sheet. The amino terminus protrudes into an internal, water-filled cavity of the lower domain and forms a buried salt bridge with Glu103; amino-terminally extended pro-forms of astacin are thus not compatible with this structure. The carboxy-terminal domain of astacin is mainly organized in several turns and irregular structures. Because they share sequence identity of about 35%, the structures of the proteolytic domains of the other "astacin" members must be quite similar to astacin. Only a few very short deletions and insertions quite distant from the active-site distinguish their structures from astacin. The five-stranded beta-sheet and the two helices of the amino-terminal domain of astacin are topologically similar to the structure observed in the archetypal zinc-endopeptidase thermolysin; the rest of the structures are, in contrast, completely unrelated in astacin and thermolysin. The zinc ion, the central alpha-helix and the zinc-liganding residues His92, Glu93 and His96 of astacin are nearly superimposable with the respective groups of thermolysin, namely with the zinc ion, the "active-site helix", and His142TL, Glu143TL and His146TL of the zinc-binding consensus motif His-Glu-Xaa-Xaa-His (where Xaa is any amino acid residue).(ABSTRACT TRUNCATED AT 400 WORDS)
J Mol Biol 1993 Feb 20
PMID:Refined 1.8 A X-ray crystal structure of astacin, a zinc-endopeptidase from the crayfish Astacus astacus L. Structure determination, refinement, molecular structure and comparison with thermolysin. 844 58

As an alternative to soluble plant transcription systems, we examined the reinitiation capacity of isolated parsley nuclei. Nuclear chalcone synthase in vitro transcripts were affinity-labelled with gamma-thio-ATP, gamma-thio-GTP or beta-thio-ATP, and purified by chromatography on a mercury Sepharose affinity column. Primer extension and subsequent PCR amplification of these in vitro transcripts revealed gamma-thio-ATP-dependent, but no beta-thio-ATP-dependent, signals, although affinity labelling of overall in vitro transcripts still occurred with beta-thio-ATP. We conclude that the described plant nuclei reinitiated transcription non-specifically and that post-transcriptional transfer of the gamma-thio affinity label severely interfered with the detection of reinitiated transcripts.
Plant Mol Biol 1993 Mar
PMID:Post-transcriptional transfer of gamma-thio affinity label to RNA in isolated parsley nuclei. 846 88


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>