702 resultados para 919
Resumo:
The fishery for spiny lobster Panulirus argus in the Florida Keys National Marine Sanctuary is well chronicled, but little information is available on the prevalence of lost or abandoned lobster traps. In 2007, towed-diver surveys were used to identify and count pieces of trap debris and any other marine debris encountered. Trap debris density (debris incidences/ha) in historic trap-use zones and in representative benthic habitats was estimated. Trap debris was not proportionally distributed with fishing effort. Coral habitats had the greatest density of trap debris despite trap fishers’ reported avoidance of coral reefs while fishing. The accumulation of trap debris on coral emphasizes the role of wind in redistributing traps and trap debris in the sanctuary. We estimated that 85,548 ± 23,387 (mean ± SD) ghost traps and 1,056,127 ± 124,919 nonfishing traps or remnants of traps were present in the study area. Given the large numbers of traps in the fishery and the lack of effective measures for managing and controlling the loss of gear, the generation of trap debris will likely continue in proportion to the number of traps deployed in the fishery. Focused removal of submerged trap debris from especially vulnerable habitats such as reefs and hardbottom, where trap debris density is high, would mitigate key habitat issues but would not address ghost fishing or the cost of lost gear.
Resumo:
本文由两部分组成,一部分是关于一组新型除草剂(K-15,K-23)的抑制特性及作用位点的研究;另一部分是关于碳酸氢盐对细胞色素b-559高电势的保护作用的研究。 在第一部分,我们首先研究了抑制剂K-23对Psn放氧活性、DCIP光还原和可变荧光等光合特性的影响。研究发现,K-23在低浓度时刺激放氧活性,而在相对高浓度时抑制放氧活性。但是,K-23在低浓度时却有效地抑制了可变荧光。这些数据表明了新型抑制剂的抑制反应是基于氧化还原作用而不是猝灭作用。此外,通过采用胰蛋白酶消化类囊体膜的方式初步检测了新型抑制剂的作用部位,其结果表明:虽然新型抑制剂抑制受体侧电子传递,但它的抑制部位与DCMU不同。 其次,研究了新型抑制剂对光系统II色素蛋白复合体与多肽组分的影响及抑制剂的键合蛋白。应用SDS-PAGE技术,发现新型抑制剂主要作用于光系统II的反应中心蛋白。用温和的Deriphat-PAGE分析也证实了新型抑制剂作用于核心复合物,导致核心复合物二聚体消失。 进一步用SDS-PAGE分析新型抑制剂对Psn多肽组分的影响,发现新型抑制剂主要影响D.、D2、CP43和CP47。用荧光发射的方法确定了K-15键合在D2蛋白上。 最后,结合荧光动力学和HPLC方法,分别从定性和定量的角度,以核心复合物以及抑制剂存在下从BBY中分离的核心复合物为研究对象,详细研究了抑制剂对QA的取代作用。研究发现,在无去垢剂或低浓度去垢剂存在情况下,由于不能创造出适合于QA存在的疏水环境,我们没有得到QA被K-15取代的实验证据。而在抑制剂K-15存在下,用2.2% HTG从BBY分离的核心复合物的实验中,检测不到正的可变荧光Fv,而是得到了降低的FM,这个结果表明QA已被抑制剂在它的作用位点处所取代。 在第二部分,研究了pH5.0—7.0范围内碳酸氢盐对Cyt b-559氧化还原状态转变的影响。首先研究了pH5.0~7.0条件下碳酸氢盐对PSII Cyt b-559还原减氧化差异吸收光谱的影响,发现铁氰化钾还原的PSII Cyt b-559 HP的含量随介质pH值的降低而减少。然而,碳酸氢盐的加入阻止了由于介质pH降低而引起的Cyt b-559由高电势向低电势的转化。比如,当样品温育在pH5.0的介质中,铁氰化钾还原的Cyt b-559 HP含量占总量的25%-30%,当介质中加入2mmol/L碳酸氢盐后Cyt b-559 HP的含量上升,占总量的50%-56%。碳酸氢盐效应对氢醌还原的Cyt b-559HP含量的影响尤为显著。pH6.5时碳酸氢盐对Cyt b-559的还原氧化状态的影响不显著。其次,分别研究了PSII经Tris处理去除锰簇和三个外周蛋白及NH20H处理去除锰簇和17 kDa和23 kDa后,碳酸氢盐对Cytb一559 HP影响的pH依赖值,发现不论在pH5.0还是pH6.5的介质中碳酸氢盐效应都不存在。 综合以上实验结果,我们认为碳酸氢盐对酸化引起的Cyt b-559氧化还原状态的影响与它和锰的作用有关,但也不能排除钙离子与碳酸氢盐之间的协同作用。
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本实用新型涉及一种RBS换靶装置是在靶架密封转动壳上连有两平行的传动链固定架,在两平行传动链固定架上设有靶链传动滚,在靶链传动滚上放有由传动链块和传动链连接片构成的传动链,在传动链块上连有带靶托的靶托转动块,靶链传动滚上连有摇柄;本实用新型一次可同时安装多块靶子、可作到换靶不破坏真空、不停束流、可大大提高工作效率。
Resumo:
主要组织相容性复合体(MHC)是与免疫应答和移植排斥直接相关的一组基因群.由于MHC高度的多态性,使其在脊椎动物的免疫遗传、进化、保护以及与疾病的相关性等方面的研究倍受关注.猕猴MHC尤其是MHC Ⅰ类基因的组成与人类有显著差异,一个单体型中存在多个Mamu-A和Mamu-B基因.在猕猴AIDS模型中,MHC对病毒的免疫逃逸以及对AIDS疫苗的研究均有十分重要的作用,某些MHC Ⅰ类和MHCⅡ类基因能够显著延缓猕猴AIDS疾病的进展,为在人体中理解MHCⅠ类等位基因与免疫保护和控制病毒复制的相关性提供了一个良好的模型.
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Major histocompatibility complex (MHC) class I information is vital for understanding variance of immune responses in HIV vaccination and biomedical models. In this study, 9 Mamu-A and 13 Mamu-B alleles were identified from the cDNA products of 10 Chinese
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Twelve new dibenzocyclooctadiene lignans, marlignans A-L (1-12), together with 16 known compounds, were isolated from the leaves and stems of Schisandra wilsoniana. The structures of 1-12 were elucidated by spectroscopic methods including 1D- and 2D-NMR techniques. Compounds 1-12 were evaluated for their anti-HIV activities, of which compounds 3, 6, 8, and 12 showed modest activities with therapeutic index values of 13.2, 15.6, 17.6, and 16.4, respectively.
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A new species of Amolops is described from a mountainous area of southern Yunnan Province, China. The species is unique in having a dark purple dorsum with small light yellow spots. The spots are smaller than the smallest finger disk. Other characters tha