蚯蚓蛋白酶解工艺及其产物分析

采用Asl.398枯草蛋白酶制备蚯蚓肽,通过单因素与正交试验设计(L9(34)),以氨基氮数,多肽浓度为衡量指标,对最佳酶条件进行筛选研究,并分析了酶解液氨基酸含量和相对分子量的分布。结果表明:最佳酶解条件为pH 6.5、酶浓度为1%、温度50℃反应、时间8 h,在此条件下,酶解蚯蚓蛋白的水解液氨基氮数可以达到16.55 mmol/100 mL,水解液多肽浓度达9.22 mg/mL,酶解液分子量大部分是在5 000以下的多肽、小肽及氨基酸的混合物,其中分子量在220以下的占了72.09%,氨基酸组成平衡,含量丰富,可用来制取新型氨基酸微量元素及小肽添加剂。     

含肽肝素渣水解物对早期断奶仔猪免疫功能的影响

本试验研究了含肽肝素渣水解物对早期断奶仔猪免疫器官生长发育、血清IgG含量、淋巴细胞数、腹泻指数以及生产性能的影响。试验表明,肝素渣水解后产生的寡肽可促进仔猪免疫器官发育,提高血清免疫球蛋白浓度、猪瘟抗体OD值和血液中淋巴细胞数,提高了断奶仔猪的免疫功能,降低了仔猪的腹泻指数,并能提高仔猪的日增重和饲料转化率。     

Bans,tests, and alchemy: Food safety regulation and the Uganda fish export industry

Contemporary regulation of food safety incorporates principles of quality management and systemic performance objectives that used to characterize private standards. Conversely, private standards are covering ground that used to be the realm of regulation. The nature of the two is becoming increasingly indistinguishable. The case study of the Ugandan fish export industry highlights how management methods borrowed from private standards can be applied to public regulation to achieve seemingly conflicting objectives. In the late 1990s, the EU imposed repeated bans on fish imported from Uganda on the basis of food safety concerns. However, the EU did not provide scientific proof that the fish were actually “unsafe.” Rather, the poor performance of Uganda’s regulatory and monitoring system was used as justification. Only by fixing “the system” (of regulations and inspections) and performing the ritual of laboratory testing for all consignments for export to the EU did the Ugandan industry regain its status as a “safe” source of fish. Yet, gaps and inconsistencies abound in the current Ugandan fish safety management system. Some operations are by necessity carried out as “rituals of verification.” Given the importance of microbiological tests and laboratories in the compliance system, “alchemic rituals” provide an appropriate metaphor. These rituals are part and parcel of a model that reassures the EU fish-eating public that all is under control in Uganda from boat to point of export. As a consequence, actual non-compliance from boat to landing site allows the fishery to survive as an artisanal operation. Stefano Ponte is Senior Researcher at the Danish Institute for International Studies, Copenhagen. His research focuses on the role of standards, regulation and quality conventions in the governance of agro-food value chains, with particular focus on Africa. He is co-author of Trading Down: Africa, Value Chains and the Global Economy and The Coffee Paradox: Global Markets, Commodity Trade and the Elusive Promise of Development.     

丝胶蛋白及其木瓜蛋白酶酶解产物的保湿性与抗氧化活性

以全天然丝胶茧为原料提取丝胶蛋白,经木瓜蛋白酶酶解,考察丝胶蛋白及其酶解产物的保湿性,并从清除DPPH自由基能力、总抗氧化能力、抑制烃基自由基能力和抗超氧阴离子自由基能力等方面分析抗氧化活性,为开发利用优质的丝胶蛋白资源的更广泛应用提供理论依据。结果表明,丝胶蛋白经木瓜蛋白酶酶解后获得5~12 kDa的酶解产物,其优良的保湿性能优于丙二醇;丝胶蛋白及其酶解产物均具有较好的抗氧化活性,其中以酶解产物的抗氧化活性更强。抗氧化能力与浓度呈明显的正相关性。     

女山湖渔业资源及鱼类增养殖措施的研究

根据女山湖天然饵料资源及鱼类组成结构状况,通过人工放流、自然增殖补充鱼类,移殖水生经济动物,逐渐调整鱼类结构组成,使湖内天然饵料资源得以合理充分利用,辅以围拦网人工养殖,水产品产量由1994年的456 kg/hm2提高到1999年的534 kg/hm2,经济效益较为显著.     

蚯蚓蛋白酶解工艺及其产物分析

采用Asl.398枯草蛋白酶制备蚯蚓肽,通过单因素与正交试验设计(L9(34)),以氨基氮数,多肽浓度为衡量指标,对最佳酶条件进行筛选研究,并分析了酶解液氨基酸含量和相对分子量的分布。结果表明:最佳酶解条件为pH 6.5、酶浓度为1%、温度50℃反应、时间8 h,在此条件下,酶解蚯蚓蛋白的水解液氨基氮数可以达到16.55 mmol/100 mL,水解液多肽浓度达9.22 mg/mL,酶解液分子量大部分是在5 000以下的多肽、小肽及氨基酸的混合物,其中分子量在220以下的占了72.09%,氨基酸组成平衡,含量丰富,可用来制取新型氨基酸微量元素及小肽添加剂。     

Community-based conservation results in the recovery of reef fish spawning aggregations in the Coral Triangle

In the Coral Triangle community-based marine protected areas (MPAs) are being established at a prolific rate. Their establishment can benefit both fisheries and biodiversity, and they provide both a socially and economically acceptable means of managing coral reefs in developing nations. However, because such MPAs are typically small (usually <0.5 km²), they will rarely provide protection to large mobile fishes. An exception to this limitation may exist when community-based MPAs are established to protect small sites where vital processes occur, such as fish spawning aggregations (FSAs). To test the effectiveness of small (0.1–0.2 km²) MPAs for protecting FSAs, we monitored three FSA sites where brown-marbled grouper (Epinephelus fuscoguttatus), camouflage grouper (Epinephelus polyphekadion) and squaretail coralgrouper (Plectropomus areolatus) aggregate to spawn. Sites were monitored during peak reproductive periods (several days prior to each new moon) between January 2005 and November 2009. All three sites are located in New Ireland Province, Papua New Guinea, and had been exploited for decades, but in 2004 two sites were protected by the establishment of community-based MPAs. The third site continued to be exploited. Over the monitoring period densities of E. fuscoguttatus and E. polyphekadion increased at both MPAs, but not at the site that remained open to fishing. At one MPA the densities of E. polyphekadion increased tenfold. Our findings demonstrate that community-based MPAs that are appropriately designed and adequately enforced can lead to the recovery of populations of vulnerable species that aggregate to spawn.     

A decision-analytic approach to the optimal allocation of resources for endangered species consultation

The resources available to support conservation work, whether time or money, are limited. Decision makers need methods to help them identify the optimal allocation of limited resources to meet conservation goals, and decision analysis is uniquely suited to assist with the development of such methods. In recent years, a number of case studies have been described that examine optimal conservation decisions under fiscal constraints; here we develop methods to look at other types of constraints, including limited staff and regulatory deadlines. In the US, Section Seven consultation, an important component of protection under the federal Endangered Species Act, requires that federal agencies overseeing projects consult with federal biologists to avoid jeopardizing species. A benefit of consultation is negotiation of project modifications that lessen impacts on species, so staff time allocated to consultation supports conservation. However, some offices have experienced declining staff, potentially reducing the efficacy of consultation. This is true of the US Fish and Wildlife Service’s Washington Fish and Wildlife Office (WFWO) and its consultation work on federally-threatened bull trout (Salvelinus confluentus). To improve effectiveness, WFWO managers needed a tool to help allocate this work to maximize conservation benefits. We used a decision-analytic approach to score projects based on the value of staff time investment, and then identified an optimal decision rule for how scored projects would be allocated across bins, where projects in different bins received different time investments. We found that, given current staff, the optimal decision rule placed 80% of informal consultations (those where expected effects are beneficial, insignificant, or discountable) in a short bin where they would be completed without negotiating changes. The remaining 20% would be placed in a long bin, warranting an investment of seven days, including time for negotiation. For formal consultations (those where expected effects are significant), 82% of projects would be placed in a long bin, with an average time investment of 15 days. The WFWO is using this decision-support tool to help allocate staff time. Because workload allocation decisions are iterative, we describe a monitoring plan designed to increase the tool’s efficacy over time. This work has general application beyond Section Seven consultation, in that it provides a framework for efficient investment of staff time in conservation when such time is limited and when regulatory deadlines prevent an unconstrained approach.     

Network thinking in riverscape conservation – A graph-based approach

Graph theoretic approaches have received increased interest recently in landscape planning and conservation in the terrestrial realm, because these approaches facilitate the effective modelling of connectivity among habitats. We examined whether basic principles of graph theory can be extended to other ecosystems. Specifically, we demonstrate how a network-based context can be used for enhancing the more effective conservation of riverine systems. We first show how to use graph theoretic techniques to model riverscapes at the segment level. Then we use a real stream network (Zagyva river basin, Hungary) to examine the topological importance of segments in maintaining riverscape connectivity, using betweenness centrality, a commonly used network measure. Using the undirected graph model of this riverscape, we then prioritize segments for conservation purpose. We examine the value of each of the 93 segments present in the Zagyva river basin by considering the conservation value of local fish assemblages, connectivity and the size of the habitat patches. For this purpose we use the ‘integral index of connectivity’, a recently advocated habitat availability index. Based on the results the selection of the most valuable habitat segments can be optimized depending on conservation resources. Because of their inherent advantage in the consideration of connectivity relationships, we suggest that network analyses offer a simple, yet effective tool for searching for key segments (or junctions) in riverscapes for conservation and environmental management. Further, although the joint consideration of aquatic and terrestrial networks is challenging, the extension of network analyses to freshwater systems may facilitate the more effective selection of priority areas for conservation in continental areas.     

金枪鱼酶解液脱色工艺及其对腥味物质和金属元素的影响

为了研究活性炭对金枪鱼酶解液脱色的最佳条件,本文利用活性炭对金枪鱼暗色肉酶解液进行处理,研究活性炭添加量、pH值、温度(T)和脱色时间(t)对脱色率和蛋白质损失率的影响,采用正交试验对脱色工艺进行优化,同时探究了活性炭脱色工艺对酶解液腥味物质和金属元素含量的影响.结果表明,金枪鱼暗色肉酶解液最佳脱色条件为活性炭添加量3％、pH值3.0、温度70℃、时间1h.该条件下脱色率为89.77％±0.77％,蛋白质损失率为13.47％±0.72％;脱色后酶解液挥发性物质含量降低了85.39％,其中三甲胺、己醛、壬醛等特征腥味物质显著降低;活性炭对Pb的吸附作用较明显,其吸附率为93.2％,而对其他金属元素的吸附率不大.研究表明,经过活性炭处理过的酶解液颜色浅,腥味低,具有一定的应用前景,可为酶解液的进一步利用提供依据.