Maternal effects on fecundity and egg quality of the Patagonian stock of Argentine Hake (Merluccius hubbsi)

The influences of age, size, and condition of spawning females on fecundity and oocyte quality were analyzed for the Patagonian stock of Argentine Hake (Merluccius hubbsi). Samples of mature females were collected in the spawning area as part of 2 research surveys conducted in January 2010 and 2011, during the peak of the reproductive season. Batch fecundity (BF) ranged between 40,500 (29 cm total length [TL]) and 2,550,000 (95 cm TL) hydrated oocytes, and was positively correlated with TL, gutted weight, age, hepatosomatic index (HSI), and the relative condition factor (Kn). Relative fecundity ranged between 85 and 1040 hydrated oocytes g–1 and showed significant positive relationships with gutted weight, HSI, and Kn; however, coefficients of determination were low for all regressions. Dry weights of samples of 100 hydrated oocytes ranged between 1.8 and 3.95 mg and were positively correlated with all variables analyzed, including batch and relative fecundity. Multiple regression models created with data of the morphophysiological characteristics of females supported maternal influences on fecundity and egg weights. Within the studied size range (29–95 cm TL), larger individuals had better somatic and egg condition, mainly revealed by higher HSI and hydrated oocytes with larger oil droplets (275.71μm [standard error 1.49]). These results were associated with the higher feeding activity of larger females during the spawning season in comparison with the feeding activity of young individuals (<5 years old); the better nutritional state of larger females, assumed to result from more feeding, was conducive to greater production of high-quality eggs.

10KD Zein 基因克隆、序列分析以及对植物百脉根（Lotus corniculatus L.）转化

本文应用聚合酶链式反应技术(PCR)在体外从玉米基因组中扩增富于含硫氨基酸的10KD玉米醇溶蛋白基因、克隆及序列分析结果，并用该基因转化豆科牧草百脉根以期获得有良好营养平衡的转基因牧草，从玉米无菌苗提取大片段的DNA．根据目的基因两端的DNA顺序合成一对引物，利用PCR技术经30个活环DNA扩增，得到了一特异的0.57Kb片段，克隆后对该片段进行限制性内切酶物理图谱分析并测定了其全部编码区序列．结果表明，克隆到的完整的10 Kd玉米醇溶蛋白基因编码区与国外报道的相比，其核苷酸顺序及推测的氧基酸序列同源率分别为96%和90%．将基因分别置于质粒pKYLX5及pKYLX71表达戴体，构建了分别在rbcS及CaMV 35S启动子调控下的10 KD zein基因的嵌合质粒．列用农杆菌介导的叶盘法及茎切段法，选用百脉根( Lotus corniculatus)品种一名分别为“里澳”及“马库”，以5-10天的无菌苗子叶和茎切段为外植体，进行基因转化，在含50mg／L km的MS培养基上，2-3周获得抗性的芽，将芽转到无激素的MS培养基上诱导生根，获得抗性植株，捡测工作正在进行中。

Diel movements of fishes linked to benthic seascape structure in a Caribbean coral reef ecosystem

Many common fishes associated with Caribbean coral reef ecosystems use resources from more than 1 patch type during routine daily foraging activities. Few studies have provided direct evidence of connectivity across seascapes, and the importance of benthic seascape structure on movement behavior is poorly known. To address this knowledge gap, we coupled hydro-acoustic technology to track fish with seafloor mapping and pattern analysis techniques from landscape ecology to quantify seascape structure. Bluestriped grunts Haemulon sciurus and schoolmaster snapper Lutjanus apodus were tracked over 24 h periods using boat-based acoustic telemetry. Movement pathways, and day and night activity spaces were mapped using geographical information system (GIS) tools, and seafloor structure within activity spaces was mapped from high-resolution aerial photography and quantified using spatial pattern metrics. For both fish species, night activity spaces were significantly larger than day activity spaces. Fish exhibited a daytime preference for seascapes with aggregate coral reef and colonized bedrock, then shifted to night activity spaces with lower complexity soft sediment including sand, seagrass, and scattered coral/rock. Movement path complexity was negatively correlated with seascape complexity. This demonstrates direct connectivity across multiple patch types and represents the first study to apply quantitative landscape ecology techniques to examine the movement ecology of marine fish. The spatially explicit approach facilitates understanding to the linkages between biological processes and the heterogeneity of the landscape. Such studies are essential for identifying ecologically relevant spatial scales, delineating essential fish habitat and designing marine protected areas.

Status of coral reef ecosystems in a marine managed area in St. Croix, USVI [poster]

This poster presents information on the status and trends of coral reef ecosystems in St. Croix, US Virgin Islands (USVI). Data were collected by NOAA’s Center for Coastal Monitoring and Assessment Biogeography Branch (CCMA-BB) from 2001-2006 at 1,275 random locations in and around Buck Island Reef National Monument (BIRNM). The main objective was to quantify changes in fish species and assemblage diversity, abundance, biomass and size structure; to provide spatially explicit information on the distribution of key species or groups of species; and to compare community structure inside versus outside of BIRNM.

Demographic assessment of the blue crab (Callinectes sapidus) in Chesapeake Bay using extractable lipofuscins as age markers

The blue crab (Callinectes sapidus) plays an important economic and ecological role in estuaries and coastal habitats from the Gulf of Mexico to the east coast of North America, but demographic assessments are limited by length-based methods. We applied an alternative aging method using biochemical measures of metabolic byproducts (lipofuscins) sequestered in the neural tissue of eyestalks to examine population age structure. From Chesapeake Bay, subsamples of animals collected from the 1998–99 (n=769) and 1999–2000 (n=367) winter dredge surveys were collected and lipofuscin was measured. Modal analysis of the lipofuscin index provided separation into three modes, whereas carapace-width data collected among the same individuals showed two broad modes. Lipofuscin modal analysis indicated that most adults (carapace width >120 mm) were <2 years old. The results indicate that use of extractable lipofuscin can provide a more accurate and better resolved estimation of demographic structure of blue crab populations in the field than size alone.

低能N+诱导拟南芥突变体DNA变异的研究

低能离子束的诱变效应首先由我国科学家发现并将其广泛应用于育种实践，但是离子注入诱导DNA变异的研究结果主要是以微生物离体质粒DNA为材料获得的，以活体高等生物为材料的研究尚未见报道。 我们以30 keV N+（注入剂量80×1015 ions/cm2）注入拟南芥后获得的稳定突变体T80II为实验材料，对突变体植株进行了RAPD标记，并将T80II和对照部分RAPD特异条带进行克隆测序和DNA序列分析。结果显示，在可分辨的总计397个RAPD条带中，T80II株系中有52个条带表现出差异，包括条带的缺失和增加，条带变异率为13.1%;克隆的T80II序列中，平均每16.8个碱基出现一个碱基变异位点，表现出较高频率的碱基突变。碱基突变的类型包括碱基的颠换、转换、缺失、插入等。在检测到的275个碱基突变中，主要是单碱基置换（97.09%），碱基缺失或者插入的比例较小（2.91%）。在碱基置换中，转换的频率（66.55%）高于颠换的频率（(30.55%)。此外，构成DNA的四种碱基均可以被离子束辐照诱发变异，而且每一种碱基都可以被其它三种碱基所替换，但是胸腺嘧啶（T）的辐射敏感性要高于其它三种碱基。通过分析突变碱基周边序列，对低能N+离子注入拟南芥突变体引发的碱基突变热点进行了讨论。 另外，低能离子注入诱变获得的突变体特异表达基因的克隆方面也没有报道。我们以突变体T80II作为实验材料，用PCR增效的减法杂交技术构建了T80II特异表达的cDNA减法文库，克隆特异表达的cDNA片段，并对其中1个与14-3-3 protein GF14 nu (GRF7) gene有部分同源性、长712 bp的cDNA片段进行了讨论。我们的研究证明通过减法杂交技术克隆低能离子诱发的突变体特异表达的cDNA是可能的，这为低能离子注入技术在分子生物学上的应用开辟了一个新思路。