鰤鱼诺卡氏菌培养条件及培养基的优化

对鰤鱼诺卡氏菌（Nocardia seriolea）ZJ0503的增菌培养基和生长条件进行优化。研究了温度、盐度、初始pH对鰤鱼诺卡氏菌生长的影响,并通过单因素试验对培养基的碳源、氮源和无机盐成分进行了筛选,采用正交实验法对培养基各主要成分的添加量进行了优化。结果表明,鰤鱼诺卡氏菌最适宜生长条件为温度25 ℃、盐度5、pH 6.5±0.2;经筛选,鰤鱼诺卡氏菌培养基中最佳碳源是葡萄糖,最佳氮源是酵母粉,促生长作用最强的2种无机盐是磷酸氢二钾（K2HPO4）和氯化钙（CaCl2）;确立了培养基优化配方为葡萄糖20 g·L-1,酵母粉15 g·L-1,K2HPO4 0.75 g·L-1,CaCl 20.2 g·L-1（单独灭菌）,氯化钠（NaCl2）5 g·L-1,pH 6.5±0.2。     

Short-term storage and cryopreservation of Urechis unicinctus (Echiura: Urechidae) sperm

In the present study, attempts were made to preserve Urechis unicinctus sperm at 4°C. Cryopreservation procedures were optimized for various cryoprotectants and freezing rates, equilibration times and dilution ratios. During short‐term storage, the motility of undiluted sperm was extended for 6 days of cold storage,and in 70% and 100% artificial seawater only persisted for 2 and 4 days respectively. The survival rate of undiluted sperm was maintained at a high level accordingly. After cryopreservation, the highest motility and survival rate (41.5±2.2%) were obtained in 15% dimethyl sulphoxide (Me₂SO) using a freezing rate of 30°C min^?1. After thawing the sperm cryopreserved in glycerol lost almost all motility. The motility and survival rate of post‐thawing sperm did not show significant differences after 8 and 15 min equilibration using 15% Me₂SO as cryoprotectant; the values were significantly higher than those of 2 min equilibration. Comparisons of motility and survival rate between treatments pooled by dilution ratio showed that the effect of 1:1 ratio (sperm volume to cryoprotectant volume) was best. There was no difference between 1:3 and 1:5, and other ratioswere significantly worse.     

Motility Parameters of Rainbow Trout (<Emphasis Type="Italic">Oncorhynchus mykiss</Emphasis>) Spermatozoa in Relation to Sequential Collection of Milt,Time of <Emphasis Type="Italic">Post-mortem</Emphasis> Storage and Anesthesia

The present study investigated the effects of sequential collection of milt, time of post-mortem storage and anesthesia on rainbow trout (Oncorhynchus mykiss) sperm motility parameters (using computer-assisted sperm analysis – CASA) as well as seminal plasma osmolality and sperm concentration. The post-mortem storage and time of anesthesia altered motility characteristics of rainbow trout sperm to different extents. The moderate impact of time of anesthesia was manifested in a shortened duration of sperm motility after 10 min exposure of fish to anesthetic. The prolonged post-mortem storage (≥40–60 min), in addition to lowering sperm motility duration, also significantly influenced sperm motility parameters, such as sperm velocities, percentage of motile sperm and sperm trajectory parameters. These results clearly demonstrate that when milt from sacrificed fish is used for sperm motility studies, the time of post-mortem storage significantly alters sperm motility characteristics. Since sperm motility rate and swimming velocity could predict fertilizing ability, detrimental effects of prolonged post-mortem storage may lead to reduced fertilization success. Sperm concentration and seminal plasma osmolality were lower in the first fractions and increased with successive collections of milt. It suggests the presence of urine contamination of the first milt fractions which were collected by stripping. Therefore, testing of sperm concentration and/or seminal plasma osmolality should be mandatory while handling stored milt.     

Influence of river conditions during seaward migration and ocean conditions on survival rates of Snake River Chinook salmon and steelhead

Petrosky CE, Schaller HA. Influence of river conditions during seaward migration and ocean conditions on survival rates of Snake River Chinook salmon and steelhead.
Ecology of Freshwater Fish 2010: 19: 520–536. © 2010 John Wiley & Sons A/S Abstract – Improved understanding of the relative influence of ocean and freshwater factors on survival of at‐risk anadromous fish populations is critical to success of conservation and recovery efforts. Abundance and smolt to adult survival rates of Snake River Chinook salmon and steelhead decreased dramatically coincident with construction of hydropower dams in the 1970s. However, separating the influence of ocean and freshwater conditions is difficult because of possible confounding factors. We used long time‐series of smolt to adult survival rates for Chinook salmon and steelhead to estimate first year ocean survival rates. We constructed multiple regression models that explained the survival rate patterns using environmental indices for ocean conditions and in‐river conditions experienced during seaward migration. Survival rates during the smolt to adult and first year ocean life stages for both species were associated with both ocean and river conditions. Best‐fit, simplest models indicate that lower survival rates for Chinook salmon are associated with warmer ocean conditions, reduced upwelling in the spring, and with slower river velocity during the smolt migration or multiple passages through powerhouses at dams. Similarly, lower survival rates for steelhead are associated with warmer ocean conditions, reduced upwelling in the spring, and with slower river velocity and warmer river temperatures. Given projections for warming ocean conditions, a precautionary management approach should focus on improving in‐river migration conditions by increasing water velocity, relying on increased spill, or other actions that reduce delay of smolts through the river corridor during their seaward migration.     

Effects of egg aging on the metabolites of ovarian fluid in rainbow trout,Oncorhynchus mykiss

Nuclear magnetic resonance ‐based metabolomics was applied to study effects of egg aging on ovarian fluid metabolites in rainbow trout, Oncorhynchus mykiss. The eggs of three females were pooled and then assigned to three plastic vials for 18 days in vitro storage at 4°C. Ovarian fluid samples were taken 0, 6, 12 and 18 days after storage. Three groups of metabolites including amino acids, osmolytes and energy metabolites were found to change during storage period. The glucose levels of ovarian fluid showed significant decreases on days 12 and 18 after storage (p < .05). For acetoacetate and acetate, significant increases were observed, respectively, on days 12 and 18 after storage (p < .05). The creatine levels of ovarian fluid increased significantly on days 12 and 18 after storage (p < .05). Lactate levels in ovarian fluid elevated during storage period (p < .05). Glycerol levels showed a significant increase on days 12 and 18 after storage (p < .05). The values of osmolytes in ovarian fluid (e.g., betaine, taurine, trimethylamine‐N‐oxide, N,N‐dimethylglycine) showed a decreasing trend on day 12 which continued until the end of storage on day 18 (p < .05). Almost all amino acids elevated on days 12 and 18 after storage (p < .05). After an apparent elevation in isoleucine levels on days 6 and 12, this amino acid decreased on day 18 after storage (p < .05). The osmolytes might act as antioxidant against free‐radicals produced as a result of over‐ripening. Glucose can be used as energy resource for eggs and bacteria during ova storage. Also, change pattern of amino acids indicate hydrolysis of proteins as the time of storage increases.     

不同培养条件对微藻总脂含量和脂肪酸组成的影响

微藻细胞中脂类的数量及质量是评价其营养价值的重要指标。大量研究表明,改变培养条件及在不同的时期收获对微藻的脂肪含量和脂肪酸组成有着显著影响。本文主要从培养基成分、光强、温度、通气量和生长期5个方面综述了相关的研究成果,希望能为海洋微藻的研究和开发利用提供有价值的参考。     

黄土高原节水生态型淤地坝建设的方法与措施

 淤地坝是黄土高原地区水土流失治理的关键措施。大规模建设淤地坝,不仅对于改善黄土高原地区的生态环境,促进经济社会的可持续发展,全面建设小康社会具有重要意义,而且对于减少入黄泥沙,确保黄河安澜也具有不可替代的重要作用。基于黄土高原地区淤地坝建设所取得的巨大成就,分析淤地坝数量、淤地面积和拦泥量按区域、流域的分布特征;针对淤地坝建设中存在的设计不合理、设计标准偏低、坝地非点源污染加剧、无效蒸发大等问题,提出了淤地坝单坝系统和节水生态型淤地坝的概念,以及建设节水生态型淤地坝的基本方法和保障措施。还分析了节水生态型淤地坝建设的案例,以期为淤地坝工程建设提供有关科学依据。