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251.
252.
海洋假单胞杆菌QD80低温碱性蛋白酶(QDAPr)具有良好的低温适应性,且与常见的增稠剂及表面活性剂有良好的配伍性.因此该蛋白酶在日用化学领域,尤其是低温洗涤领域,具有广泛的应用价值.为研究其结构与功能之间的关系,用EDC、PMSF、N-AI、2,3-丁二酮等8种化学修饰剂修饰该低温碱性蛋白酶,然后检测残余酶活力,借以研究酶分子中氨基酸侧链基团与酶活性中心的关系.结果表明,羧基、丝氨酸、ε-氨基、巯基等残基与酶活性无关;而色氨酸、组氨酸、酪氨酸残基侧链的化学修饰引起酶活性的大幅度下降,说明色氨酸、组氨酸、酪氨酸残基是酶活力所必需的基团.精氨酸残基侧链的化学修饰引起酶活性的轻微下降,说明精氨酸对酶活性具有一定贡献,但不处于活性中心.图5表2参18 相似文献
253.
254.
Viability Analysis of Reef Fish Populations Based on Limited Demographic Information 总被引:1,自引:0,他引:1
JEFFREY WIELGUS‡ FORD BALLANTYNE IV † ENRIC SALA† LEAH R. GERBER 《Conservation biology》2007,21(2):447-454
Abstract: Marine protected areas (MPAs) that allow some degree of artisanal fishing have been proposed to control the overexploitation of marine resources while allowing extraction by local communities. Nevertheless, the management of MPAs is often impaired by the absence of data on the status of their resources. We devised a method to estimate population growth rates with the type of data that are usually available for reef fishes. We used 7 years of spatially explicit abundance data on the leopard grouper ( Mycteroperca rosacea ) in an MPA in the Gulf of California, Mexico, to construct a matrix population model that incorporated the effects of El Niño/La Niña Southern Oscillation on population dynamics. An environmental model that estimated different demographic estimates for El Niño and La Niña periods performed better than a single-environment model, and a single-habitat model performed better than a model that considered different depths as different habitats. Our results suggest that the population of the leopard grouper off the main island of the MPA is not viable under present conditions. Although the impact of fishing on leopard grouper populations in the MPA has not yet been established, fishing should be closed as a precautionary measure at this island if a priority of the MPA is to ensure the sustainability of its fish populations. 相似文献
255.
Lag Effects in the Impacts of Mass Coral Bleaching on Coral Reef Fish, Fisheries, and Ecosystems 总被引:5,自引:0,他引:5
NICHOLAS A. J. GRAHAM‡‡ SHAUN K. WILSON† SIMON JENNINGS‡ NICHOLAS V. C. POLUNIN JAN ROBINSON§ JUDE P. BIJOUX TIM M. DAW†† 《Conservation biology》2007,21(5):1291-1300
Abstract: Recent episodes of coral bleaching have led to wide-scale loss of reef corals and raised concerns over the effectiveness of existing conservation and management efforts. The 1998 bleaching event was most severe in the western Indian Ocean, where coral declined by up to 90% in some locations. Using fisheries-independent data, we assessed the long-term impacts of this event on fishery target species in the Seychelles, the overall size structure of the fish assemblage, and the effectiveness of two marine protected areas (MPAs) in protecting fish communities. The biomass of fished species above the size retained in fish traps changed little between 1994 and 2005, indicating no current effect on fishery yields. Biomass remained higher in MPAs, indicating they were effective in protecting fish stocks. Nevertheless, the size structure of the fish communities, as described with size-spectra analysis, changed in both fished areas and MPAs, with a decline in smaller fish (<30 cm) and an increase in larger fish (>45 cm). We believe this represents a time-lag response to a reduction in reef structural complexity brought about because fishes are being lost through natural mortality and fishing, and are not being replaced by juveniles. This effect is expected to be greater in terms of fisheries productivity and, because congruent patterns are observed for herbivores, suggests that MPAs do not offer coral reefs long-term resilience to bleaching events. Corallivores and planktivores declined strikingly in abundance, particularly in MPAs, and this decline was associated with a similar pattern of decline in their preferred corals. We suggest that climate-mediated disturbances, such as coral bleaching, be at the fore of conservation planning for coral reefs. 相似文献
256.
海洋微藻活体及乙醇固定状态下基因组DNA的微量提取方法 总被引:1,自引:0,他引:1
探讨了海洋微藻活体及固定状态下基因组DNA的提取方法,即作者改进的CTAB法.结果表明,CTAB改进法提取的基因组DNA蛋白质、酚、盐和小分子的污染较少,多糖成份也得到了有效去除.用5%乙醇固定样本提取DNA的效果最好,对原生动物抑制效果也较明显;10%以上的乙醇可杀死原生动物,但对DNA的降解率较大;30%以上的乙醇对细菌抑制较明显,但DNA都有较大程度的降解.本法提取的DNA可用于正常的酶切和PCR.用甲醛、甲醇/冰醋酸等其它固定液固定样品,DNA的得率低或者质量和纯度低.图7表1参27 相似文献
257.
核糖体RNA基因在海洋动物分子系统学中的应用 总被引:5,自引:0,他引:5
随着分子遗传标记在分子系统学中应用的发展,核糖体RNA基因因其特殊的组成结构和演化方式被广泛应用于海洋动物分子系统学研究中.本文系统地介绍了真核生物核糖体RNA基因的组成和性质及其近年来在海洋动物系统进化、分类和种质鉴定、遗传多样性研究等方面研究中的应用.从中可以看出,核糖体RNA基因已经广泛应用于海洋动物的分子系统学研究中,但主要利用的是核糖体RNA基因的一级结构.图2参36 相似文献
258.
Abstract: Numerous ecological studies have demonstrated the dramatic effects that humans have on coastal marine ecosystems. Consequently, marine reserves have been established to preserve biodiversity. Recent reviews show that this strategy has paid off because inside reserves, most species have rapidly increased in size and abundance. Even though these studies focused on free-living organisms and paid little attention to parasite populations, numerous authors support the hypothesis that parasitism levels could be good indicators of ecosystem stability. We examined harvesting effects on the dynamics of a parasitic trematode ( Proctoeces lintoni ) that completes its life cycle in intertidal mussels ( Perumytilus purpuratus ), keyhole limpets ( Fissurella crassa ), and clingfish ( Sicyases sanguineus ). All of these species are directly or indirectly affected by humans. Prevalence and abundance of the trematode P. lintoni in the three host species were compared in four study sites that differed in the intensity of human harvest. Parasitism infection in limpets and mussels was significantly higher in areas protected from human harvesting than in open-access areas, which suggests a significant change in parasite dynamics inside reserves. Yet the average parasitic biomass found in the gonads of F. crassa did not differ between protected and open-access areas. These results show, then, that the parasite system responded by increasing infection rates in marine protected areas without implication for reproductive success of the intermediate host. Our findings show that the indirect effects of harvesting by humans on the embedded parasite communities of littoral ecosystems require further scientific investigation. 相似文献
259.
260.
Use of Traditional Ecological Knowledge in Marine Conservation 总被引:6,自引:0,他引:6
JOSHUA A. DREW† 《Conservation biology》2005,19(4):1286-1293
Abstract: Traditional ecological knowledge (TEK) represents multiple bodies of knowledge accumulated through many generations of close interactions between people and the natural world. TEK and its application via customary ecological management plans can be useful in modern conservation programs. I disaggregate the term TEK into its constituent parts and show several ways in which TEK can strengthen research designs by increasing locality-specific knowledge, including environmental linkages occurring in those localities. Examples of the uses of TEK in conservation include folk taxonomy in systematics in Micronesia, species knowledge for conservation in Kiribati, and fishers' knowledge of ecological interactions for reserve design in Belize. When conservationists recognize the utility of TEK, they can engage in an equitable exchange of knowledge and foster shared responsibility with indigenous people. These types of exchanges can also provide an opportunity for indigenous people to develop a scientific infrastructure. 相似文献