Population genetics of Cobia (Rachycentron canadum): implications for fishery management along the coast of the southeastern United States

Cobia (Rachycentron canadum) is a pelagic, migratory species with a transoceanic distribution in tropical and subtropical waters. Recreational fishing pressure on Cobia in the United States has increased substantially during the last decade, especially in areas of its annual inshore aggregations, making this species potentially susceptible to overfishing. Although Cobia along the Atlantic and Gulf coasts of the southeastern United States are currently managed as a single fishery, the genetic composition of Cobias in these areas is unclear. On the basis of a robust microsatellite data set from collections along the U.S. Atlantic coast (2008–09), offshore groups were genetically homogenous. However, the 2 sampled inshore aggregations (South Carolina and Virginia) were genetically distinct from each other, as well as from the offshore group. The recapture of stocked fish within their release estuary 2 years after release indicates that some degree of estuarine fidelity occurs within these inshore aggregations and supports the detection of their unique genetic structure at the population level. These results complement the observed high site fidelity of Cobias in South Carolina and support a recent study that confirms that Cobia spawn in the inshore aggregations. Our increased understanding of Cobia life history will be beneficial for determining the appropriate scale of fishery management for Cobia.

Effects of reducing nutrient loads to surface waters within the Mississippi River Basin and the Gulf of Mexico: Topic 4 Report for the Integrated Assessment on Hypoxia in the Gulf of Mexico

The overall goal of this assessment was to evaluate the effects of nutrient-source reductions that may be implemented in the Mississippi River Basin (MRB) to reduce the problem of low oxygen conditions (hypoxia) in the nearshore Gulf of Mexico. Such source reductions would affect the quality of surface waters—streams, rivers, and reservoirs—in the drainage basin itself, as well as nearshore Gulf waters. The task group’s work was divided into addressing the effects of nutrient-source reductions on: (1) surface waters in the MRB and (2) hypoxia in the Gulf of Mexico.

A CMOS analogue predistortion circuit for wideband optical fibre links

The laser is a major source of nonlinearity for optical fibre communication systems. In this paper, we propose a CMOS analogue predistortion circuit to reduce laser nonlinearity for wideband optical fibre links. The circuit uses a nonlinearity having the inverse transfer characteristic of the directly modulated vertical cavity surface emitting laser (VCSEL). It is shown by post-layout simulation that the predistortion circuit shows 12dBm improvement in the optical fibre system. The optical fibre transmitter front-end with predistortion lineariser is being fabricated using the austriamicrosystems (AMS) 0.3 5μm CMOS technology.

非晶状体βγ-晶状体蛋白与三叶因子蛋白复合物的细胞核转运及其选择性杀伤肿瘤细胞机制的研究

非晶状体βγ晶状体蛋白与三叶因子蛋白复合物(βγ-CAT)是从大蹼铃蟾(Bombina maxima)皮肤分泌物中分离的分子量为72 kDa的天然蛋白复合物.本研究通过激光共聚焦显微镜和Westem blot分析βγ-CAT在人脐静脉内皮细胞(HUVEC)中的细胞核转运机制,以及βγ-CAT对多株肿瘤细胞(HCT116,HT29,A375,Hela,THP-1等)的细胞毒效应.结果表明:βγ-CAT的α亚基中含有典型的GTP/ATPase的保守结构模体Walker A和Walker B,体外检测到βγ-CAT具有GTP/ATP水解酶和GTP/ATP结合活性.在细胞核转运过程中,βγ-CAT的α亚基和β亚基参与形成约150kDa含有泛素化修饰信号的大分子复合物,且泛素化修饰信号和βγ-CAT的α亚基和β亚基共定位于细胞内和融合于细胞核区域的转运囊泡小体中.βγ-CAT能够选择性的杀伤肿瘤细胞,诱导肿瘤细胞脱落和发生凋亡.上述结果为进一步深入研究阡βγ-CAT的细胞核转运和调节细胞功能的分子作用机制提供思路和线索.

Acute toxicity of four heavy metals to Sphaeroma walkeri and Ciroiana bovina (Crustacea:Isopoda)

The median lethal concentrations (LC50) of two Isopoda species exposed to each tested metal (Cu. Co, Cd and Zn) in static tests for different exposure periods are quite variable depending on the tested metal The LC50 values for Sphaeroma walkeri after 24 hours exposure to Cu and Co were estimated graphically to be 11.20 and 7.00 mg/1 respectively. The correspoding values for Cirolana bovina exposed to Cu, Co, Cd and Zn were 3.60, 11.0, 3.80 and 4.80 mg/1 respectively. For 2 days the LC50 of S. walkeri exposed to Cd was 5.60 mg/l, but it was 10.10 mg/l for 3 days exposure to Zn. After prolonged exposure the LC50 values decreased proportionally with the exposure duration of the test the percentages of surviving animals demonstrated a progressive decrease with increasing concentratins as a main factor from the analysis of variance (ANOV A). The sensitivity of adult S. walkeri exposed to the four heavy metals for different exposure times ranked: Cd>Co>Zn>Cu. Cirolana bovina appeared to be more sensitive to Cu. Cd and Zn than to Co. Species in order of increasing sensitivity is C. bovina more than S. walker.