983 resultados para BIOLOGICAL RELEVANCE


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Adverse effects of toxic substances on the environmental quality have become a subject of concern in recent years. Toxicity of heavy metals has never been in dispute and therefore their presence in our natural environment is undesirable. This study was undertaken to establish the capability of Perna viridis as a monitor for pollution in the Manora channel. Accumulation of Zinc, Copper, Iron and Manganese by marine mussels, sampled from Manora channel, was determined. Metal load varied markedly between individuals from the same populatin. This variability was partly accounted for systematic relationship between metal load and body weight and age. The distribution of metal between the major organs was considered, but the analysis of separate organs showed no advantage for their use as a biological monitor. comparison between Iron, Manganese, Copper and Zinc concentration in ambient sea water and in the mussel showed no clear correspondence. The results suggest that the mussel is capable of acting as a biological monitor, although may not be a good short term monitor of Iron, Manganese, Zinc and Copper. It may have potential as a long term and site comparison monitor for metals, once inherent variability is taken into account

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Several biochemical and biological activities such as phospholipase A(2), arginine esterase, proteolytic, L-amino acid oxidase, 5'nucleotidase, acetylcholinesterase, thrombin-like, anticoagulant, and hemorrhagic activities were determined for whole desiccated venom of Trimeresurus jerdonii. An acidic phospholipase (named TJ-PLA(2)) was purified by anionic exchange chromatography, gel filtration, and reverse phase HPLC. TJ-PLA(2) had a molecular weight of 16,000 and a pI of 4.8. TJ-PLA(2) was non-lethal to mice up to an i.p. dose of 15 mg/kg body weight and lacked neurotoxicity and myotoxicity. It induced edema in the footpads of mice. The purified enzyme inhibited ADP- and collagen-induced human platelet aggregation in a manner which was both dose- and time-dependent.

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A novel disintegrin, jerdonin, was purified from the Trimeresurus jerdonii venom by means of gel filtration and reverse phase high pressure liquid chromatography. Its coding cDNA was also isolated from the venom gland. The jerdonin coding cDNA is part of

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An L-amino acid oxidase (TM-LAO) from the venom of Hunan Trimeresurus mucrosquamatus was purified to homogenicity by three steps including DEAE Sephadex A-50 ion-exchange chromatography, Sephadex G-75 gel filtration and Resourse Q ion-exchange chromatography. TM-LAO is composed of two identical subunits with a molecular weight of 55 kD by SDS-polyacrylamide gel electrophoresis. The molecular weight was different with that of LAO purified from the same species distributed in Taiwan that was 70 kD. The 24 N-terminal ammo acid sequence of TM-LAO is ADNKNPLEECFRETNYEEFLEIAR, which shares high similarity with other Viperid snake venom LAOs and has moderate similarity with Elapid snake venom LAOs. Further studies found that TM-LAO inhibited the growth of E. colt, S. aurues and B. dysenteriae. TM-LAO also showed cytotoxicity and platelet aggregation activity. All the biological activities were eliminated by catalase, a H2O2 scavenger. It shows that these biological effects are possibly due to the formation of H2O2 produced by TM-LAO.

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A total of 45 ponds used for fish polyculture were investigated in three zones of Bangladesh to identify the differences among the zones in respect to aqua-ecology, culture practices, fish productivity and health management. Four hundred and fifty fish from three zones were clinically examined by naked eye and histopathology. Out of total number of fish examined, 45 fish from Dhaka zones were examined for parasites and bacteria in addition to histopathology. Faded and haemorrhagic gill, skin, fin, scale loss and lesions were observed during fish examination. Aeromonas spp. Pseudomonas spp. and Streptococcus spp. were isolated respectively from 56%, 46% and 39% affected fish. Among the five water quality parameters analyzed, the highest average hardness and alkalinity respectively were recorded in Rajshahi (156 ppm and 142 ppm) followed by Dhaka (146 ppm and 132 ppm) and Chittagong (81 ppm and 90 ppm). The highest average pH was recorded in Mymensingh (7.52) followed by Rajshahi (7.13) and Chittagong (7.05). Water holding capacity of soil in Rajshahi zone was poor compared to other zones and farmers were found to be reluctant to fish farming.

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In total, 1218 Chinese from twelve ethnic groups and nine Han geographic groups were screened for the mtDNA 9-bp deletion motif. The frequency of the 9-bp deletion in all samples was 14.7% but ranged from 0% to 32% in the various ethnic groups. Three individuals had a triplication of the 9-bp segment. Phylogenetic and demographic analyses of the mtDNA hypervariable segment 1 (HVS1) sequences suggest that the 9-bp deletion occurred more than once in China. The majority of the Chinese deletion:haplotypes (about 90%) have a common origin as a mutational event following an initial expansion of modem humans in eastern Asia. Other deletion haplotypes and the three haplotypes with a 9-bp triplication may have arisen independently in the Chinese, presumably by replication error. HVS1 haplotype analysis suggests two possible migration routes of the 9-bp deletion in east and southeast Asia. Both migrations originated in China with one route leading to the Pacific Islands via Taiwan, the other to southeast Asia and possibly the Nicobar Islands. Along both routes of peopling, a decrease in HVS1 diversity of the mtDNA haplotypes is observed. The "Polynesian motif (16217T/C, 16247A/G, and 16261C/T)" and the 16140T/C, 16266C/A, or C/G polymorphisms appear specific to each migration route.

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The phylogenetic relationship of several subspecies of Ovis ammon were analyzed by comparing DNA sequences within the entire mitochondrial D-loop region. Five putative subspecies of ammon (dalai-lamae, darwini, hodgsoni, sairensis and adamerzi) were sampled from four provinces in China [Xinjiang, Qinghai, Gansu and Xizang (Tibet)] and two (servertzovi and nigrimontana) from Uzbekistan. The argalis sampled represent most of the currently recognized putative Subspecies of argali. Analysis of mtDNA sequences revealed high variability within ammon (7.7%), ranging from 2.4 to 11.5%. MaxiMUM-Parsimony tree indicated that nigrimontana from Uzbekistan diverged First, followed by severtzovi from Uzbekistan. The dispersal of argalis into China gave rise to three clades, suggesting that the argali originated in Western Asia and then dispersed throughout the central Asian highlands on a southeastward course. Among the Chinese argalis, mtDNA analysis places dalailamae genetically closer to hodgsoni than to darwini. Severtzovi and.. nigrimontana are two separate subspecies and genetically distinct from the Chinese argali.

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Rice bran is widely used by fish farmers as supplementary feed while soybean cake is used both as feed and as fertilizer in fishponds. Both fish meal and shrimp head have been found acceptable as feed ingredients. However, not much is known of the acceptability and efficiency of a mixture of these ingredients as feed for Penaeus monodon larvae. Ninety 127-day old P. monodon were measured for length and weight and were randomly divided into nine aquaria each containing 20 liters of water. These were fed 'lampirong' for two months previous to the study. There were three replications for each treatment. Length, weight, and survival rates were used to compare the efficiency of the diets. Weighed amounts of pellets equivalent to 100% of the body weight were fed during the first three days and reduced to 50% thereafter. A stopwatch was used to determine the length of time that elapsed before the shrimps would approach the pellet. Ten shrimps approximately 4 months in age were placed in 10 liters of water in a 25-liter aquarium. Two grams of each pellet type were placed simultaneously on opposite sides of the aquarium. The time that elapsed from the moment the pellets sunk to the bottom up to the time that any one shrimp approached the pellets was recorded. The group fed the imported pellets gained the most. Those fed FP-2s-77 elongated faster than those fed FP-1s-77. Survival rate of those fed FP-2s-77 was 37% while those fed imported pellets was 73%. Both 1s and 2s pellets disintegrated in water easily but the imported pellets were stable even after six hours in water. The attractability test for the pellets showed that the prawns were more readily attracted to the pellets 1s and 2s than to the imported pellets.

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Rubriflordilactones A (1) and B (2), two novel highly unsaturated rearranged bisnortriterpenoids possessing a biosynthetically modified aromatic D-ring, were isolated from the leaves and stems of Schisandra rubriflora. Their structures were established on

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A variety of N-acetyl-o-aryl-1,2-didehydroethylamines were synthesized by direct reduction-acetylation of beta-aryl-nitroolefins and assayed as HIV-1 non-nucleoside reverse transcriptase inhibitors (NNRTIs) for the first time. Compound 7a exhibited a TI v