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1.
The usefulness of benthic multi-metric indices when assessing seafloor integrity across broad environmental gradients should be deliberated, as their lack of transparency might hide important sources of variation and fail to identify environmental change. This study compares the performance of two multi-metric indices; the Benthic Quality Index (BQI) and the Brackish water Benthic Index (BBI) between three sub-basins in the Baltic Sea. Both indices reflect the salinity-driven gradient in macroinvertebrate diversity and composition as well as changes in bottom water oxygen concentrations. The relative contribution of predictor variables for explaining index variation does, however, differ between sub-basins, resulting in the indices representing different aspects of the benthic community along the environmental gradient. This context-dependency is caused by inherent differences in benthic community characteristics between the sub-basins of the Baltic Sea, and how the communities are portrayed by the indices. An increased transparency of the importance of the different predictors for directing index values is needed for coherent classifications over broad environmental gradients, such as those occurring in large estuarine water bodies. Use of a weight of evidence table to combine multiple indicators would preserve transparency and be more likely to provide a robust assessment method that would detect seafloor degradation at an early stage.  相似文献   
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The genetic diversity among the Turkish cultivars of common bean (Phaseolus vulgaris L.) was estimated by studying the Sequence Related Amplified Polymorphism (SRAP), Peroxidase Gene Polymorhism (POGP), and Chloroplast Simple Sequence Repeats (cpSSR) markers. The unweighted pair group method arithmetic average (UPGMA) and Neighbor joining (NJ) algorithm resulted in a dendrogram representing the genetic relationship among major common bean cultivars grown in Turkey. The dendrogram generated two groups possibly representing two different major gene pools. By using three different marker systems, 194 alleles were detected and 118 were found to be polymorphic. For SRAP, POGP and cpSSR, 64, 64 and 26% polymorphism ratio were obtained, respectively. Principal Component Analysis (PCA) was also carried out to determine genetic variation among common bean genotypes and three different groups were generated. The individuals were placed into three different populations in structure analysis. Three populations created in structure analysis were exactly corresponded to the three groups in PCA. Analysis of Molecular Variance (AMOVA) was used to partition the genetic variations. The percentage of the variance was approximately 59%, 3%, and 38% among groups, among populations within groups and, within populations, respectively. The percentages of variation were found to be significantly high within the populations and among the groups.  相似文献   
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大型水母声学观测与评估技术研究进展   总被引:1,自引:0,他引:1  
20世纪末以来,世界多个海域频繁出现大型水母暴发现象,对海洋生态系统、海洋渔业、沿海工业和滨海旅游业带来了巨大的灾难。为了研究大型水母生态习性,进而揭示其暴发机理并进行灾害的预警防治,近些年来国内外学者开展了大量的采用网具、目视、水下摄像、声学技术、航空影像等多种手段的大型水母监测调查工作,其中使用声学技术对大型水母进行资源评估和行为跟踪目前在欧美、日本、韩国等渔业发达国家已经开展了相关应用,在资源评估、运动学规律等研究中展现出较好的观测效果和应用潜力。目前我国在大型水母声学观测研究应用领域鲜有文献报道,通过介绍国际上利用声学技术对大型水母进行资源调查与评估、空间分布监测、运动规律等研究成果,为今后我国开展大型水母声学调查研究提供理论基础和科学依据。通过本文的分析,建议可以借鉴国际上采用科学鱼探仪、高分辨率成像声呐、声学信标等方法对大型水母进行监测调查和资源评估的研究成果,结合实际情况将声学技术逐步研究并应用到我国大型水母资源调查与评估、自然生态习性研究、重点水域大型水母动态监测预警中去,完善我国大型水母监测调查体系。  相似文献   
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为研究人工鱼礁对产卵鱼类的诱集效果和庇护效应,2014—2015年对青岛崂山青山湾海域人工鱼礁区及附近海域鱼卵和仔稚鱼的种类组成和数量分布进行了水平和垂直拖网调查. 2014年春、夏、秋3个季节的7个航次调查中,共采集鱼卵7306粒、仔稚鱼52尾,隶属于4目9科11属12种;2015年同期进行的13个航次调查中,共采集鱼卵10373粒、仔稚鱼159尾,隶属于6目11科14属15种.2年间鱼卵和仔稚鱼样品均以鲈形目数量最多,鲽形目次之,其中鱼卵样品中仅有少鳞鱚和短吻红舌鳎构成优势种;仔稚鱼样品以少鳞鱚优势度最高,但不存在仔稚鱼优势种.鱼卵和稚鱼的高优势度物种的季节间演替明显.春、夏、秋季鱼类浮游生物群落Margalef丰富度指数、Shannon多样性指数和Pielou均匀度指数平均值均较低,说明该海域鱼类浮游生物群落结构稳定性较低.2年间所采集物种对应的成鱼平均营养级分别为3.71和3.78,均属第三营养级中的低级肉食性鱼类,绝大多数为暖温种,无冷温性种类,表现出明显的暖温带特点.综合分析认为,人工鱼礁区鱼类浮游生物群落的多样性相对较高,这与鱼礁区流速和流场特征及复杂的空间异质性有关.  相似文献   
6.
Eight new iridal-type triterpenoid derivatives, including two noriridals with ether bridge (12); two iridals lactone (34), four monocyclic iridals (58), together with five known iridals (914) were identified from the rhizome of Belamcanda chinensis. Their structures were elucidated on the basis of comprehensive spectroscopic methods and electronic circular dichroism (ECD) calculations. Bioassay results showed that belamcanoxide B (1) exhibited moderated cytotoxic activities against HCT-116 and MCF-7 cell lines with IC50 values of 5.58 and 3.35 μM.  相似文献   
7.
枯草芽孢杆菌抗菌肽生物合成的研究进展   总被引:1,自引:0,他引:1  
革兰氏阳性菌模式生物——枯草芽孢杆菌能分泌多种肽类及由肽类衍生的抗菌活性物质,按合成途径不同,可分为核糖体肽和非核糖体肽。其中,非核糖体肽分子量较小,一般为3000Da以下,其生物合成是通过多功能复合酶系——非核糖体肽链合成酶来完成的,多发生在菌体生长停止之后;而核糖体肽分子量较大,其合成多于菌体快速生长时期。非核糖体肽链合成酶和核糖体肽的合成及其调控均需基因参与,而这一系列基因就构成了各种抗菌肽生物合成的基因簇。对核糖体肽和非核糖体肽的生物合成及其相关调控机制进行了综述。  相似文献   
8.
Acid-promoted, selective production of 5-hydroxymethylfurfural (HMF) under high fructose concentration conditions was achieved in ionic liquids (ILs) at 80 °C. A HMF yield up to 97% was obtained in 8 min using 1-butyl-3-methylimidazolium chloride ([C4mim]Cl) catalyzed with 9 mol % hydrochloric acid. More significantly, an HMF yield of 51% was observed when fructose was loaded at a high concentration of 67 wt % in [C4mim]Cl. Water content below 15.4% in the system had little effect on HMF yield, whereas a higher water content was detrimental to both reaction rate and HMF yield. In situ NMR analysis suggested that the transformation of fructose to HMF was a highly selective reaction that proceeded through the cyclic fructofuranosyl intermediate pathway. This work increased our capacity to produce HMF, and should be valuable to facilitate cost-efficient conversion of biomass into biofuels and bio-based products.  相似文献   
9.
癌细胞原代培养对化疗药物敏感性的探讨   总被引:4,自引:0,他引:4  
目的通过对不同抗癌药物敏感性做比较,以期寻找各自的合理化疗用药方案,从而指导不同癌症病人的化疗。方法通过肿瘤细胞体外药敏试验(即四甲基偶氮唑盐着色法,MTT),对161例肿瘤(胃癌28例,肠癌38例,膀胱癌8例,乳腺癌33例,其他肿瘤54例)新鲜瘤组织进行表阿霉素(EADM)、氨甲蝶呤(MTX)、丝裂霉素(MMC)、长春新碱(VCR)、5-氟脲嘧啶(5-FU)、羟基喜树碱(OPT)、顺铂(DDP)、卡铂(CBP)、环磷酰胺(CTX)、足叶乙甙(VP-16)、β-揽香烯(β-elemene)11种化疗药物敏感性检测,并对其结果进行比较。结果11种抗癌药对不同的肿瘤类型耐药率不同。结论各种类型肿瘤细胞对化疗药物的选择虽有一定共性,但同种肿瘤的不同个体对同种化疗药物的抑制率差异却存有显著性。肿瘤细胞体外药物敏感性测定对肿瘤病人个体的化疗具有一定价值。  相似文献   
10.
目的建立快速、灵敏、特异的分子生物学检测卫氏并殖吸虫的方法。方法根据卫氏并殖吸虫的特异性基因序列,设计适合于PCR检测的特异性引物及实时荧光PCR特异性引物和探针,并进行灵敏性和特异性试验。结果设计的引物和探针特异性强,所建立的检测方法灵敏度高。应用实时荧光PCR方法的检测灵敏度可达到0.1 pg/μL,比PCR方法的灵敏度高三个数量级。结论本研究所建立的PCR和实时荧光PCR技术检测卫氏并殖吸虫方法的特异性强,灵敏度高,为卫氏并殖吸虫感染的诊治提供了快速的检测技术手段。  相似文献   
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