远东龟铁甲的生活史和种群动态研究

远东龟铁甲Cassidispa relicta Medvedev是近年来在内蒙古大青山国家级自然保护区白桦Betula platyphylla天然次生林首次发生危害的食叶害虫,属于中国新纪录种。通过野外调查与室内饲养相结合的研究方法,观察、记录远东龟铁甲的生物学特性和发生规律。研究表明:该虫1 a发生1代,4月中下旬开始化蛹,5月中旬出现成虫,6月上旬产卵,6月底孵化幼虫,虫龄4龄,10月初开始随落叶下树越冬,幼虫喜欢在落叶下层越冬,越冬幼虫死亡率高,成虫羽化率为20.7%。     

中国对虾糠虾幼体病原菌（非01群霍乱弧菌）的研究

本文对中国对虾糠虾幼体的一种病原菌———非０１群霍乱弧菌作了研究报道。这种病的症状是病虾运动能力差、趋光性弱、镜检发现肠道肿胀。从垂死病虾中分离到５株细菌，经感染健康糠虾幼体得到与病虾相同症状。５株细菌的４７项形态及生理生化特性与霍乱弧菌相同，但不被０１群霍乱弧菌多价血清凝集。血清学分型结果均为不同的ＶＢＯ血清型ＶＢＯ５，１４，２６，４７，５６。用ＤＮＡ霍乱ＣＴ基因探针菌落原位杂交及小鼠肠结扎法测肠毒素，表明菌株有强毒力。分离菌株对小鼠的ＬＤ５０为１５８×１０８个／只。     

Long-term variation in the population structure of Arctic charr, Salvelinus alpinus, and brown trout, Salmo trutta

The effects of induced water level fluctuations and introduction of the mysid Mysis relicta Lovén on population structure of brown trout, Salmo trutta L., and Arctic charr, Salvelinus alpinus (L.), were studied during 1953–1995 in Limingen hydroelectric reservoir, Norway. The main response was a marked reduction in catch‐per‐unit‐effort (CPUE) for trout and charr, probably caused by reduced recruitment following increased variation in water level. For both species, mean length decreased until 1967 and increased thereafter, whereas mean mass‐at‐length increased for the whole period. Both length and mass‐at‐length were negatively correlated with CPUE. The increases in mean length and mass‐at‐length were probably because of reduced competition following the reduced recruitment. Mysis relicta has become an important food item for charr but not for brown trout, but the increases in mean length and mass‐at‐length of charr started prior to the appearance of M. relicta in the charr diet.     

Long-term variation in diet of Arctic char, Salvelinus alpinus, and brown trout, Salmo trutta: effects of changes in fish density and food availability

Abstract  The diet of Arctic char, Salvelinus alpinus (L.), and brown trout, Salmo trutta L., was studied in a large Norwegian reservoir over the first four decades (1954–1995) of regulation. Significant changes in diet occurred concurrent with changes in fish density and prey availability. Reduced biomass of fish due to the effect of hydropower development probably led to reduced inter- and intra-specific competition. Consumption of zoobenthos increased for both species during the first decade, fish then became an important food item concurrent with an increase in small-sized Arctic char in the littoral zone. The diet of Arctic char, but not brown trout, then changed radically as the introduced mysid, Mysis relicta Lovén, became an important food item.     

中国对虾糠虾幼体病原哈氏弧菌的鉴定及毒力基因检测

2011年春季对江苏连云港某对虾育苗场中国对虾Fenneropenaeus chinensis病死糠虾幼体分离到优势生长菌,对分离菌进行致病性、形态与生理生化特征及16S rRNA和gyrB基因同源性与系统发育分析。结果显示,引起糠虾幼体大量死亡的病原为哈氏弧菌Vibrio harveyi,菌株kx1对中国对虾仔虾和日本对虾仔虾的半数致死量LD50分别为2.0×106CFU/ml和7.0×105CFU/ml。为进一步明确分离菌株毒力基因的携带情况,进行了分离鉴定的4株病原菌对群体效应调节基因(luxR)、毒力调控基因(toxR)、溶血素基因(vhhA和vhhB)、金属蛋白酶基因(vhpA和vhpB)、毒力相关基因(toxS)、鞭毛结构基因(flaA)及锌金属蛋白酶基因(pap6)共9种毒力基因的检测,结果表明,4株病原菌均可检测到luxR、toxR、vhhA、vhhB和pap6毒力基因,扩增片段大小分别为679、390、1324、216和355 bp,其他4种毒力基因未检测到。分离鉴定的4株病原哈氏弧菌携带相同的毒力基因,这些毒力基因可作为检测致病性哈氏弧菌的生物学标记。     

Declines in deepwater sculpin Myoxocephalus thompsonii energy density associated with the disappearance of Diporeia spp. in lakes Huron and Michigan

Pothoven SA, Hondorp DW, Nalepa TF. Declines in deepwater sculpin Myoxocephalus thompsonii energy density associated with the disappearance of Diporeia spp. in lakes Huron and Michigan.
Ecology of Freshwater Fish 2011: 20: 14–22. Published 2010. This article is a US Government work and is in the public domain in the USA. Abstract – The deepwater sculpin Myoxocephalus thompsonii is a glacial relict in the Laurentian Great Lakes that primarily consumes two glacial relict crustaceans, Mysis relicta and Diporeia spp. Deepwater sculpin were collected in Lake Michigan off Little Sable Point (in 2001) and Muskegon, Michigan (in 2001 and 2009), and in Lake Huron off Harbor Beach, Michigan (in 2007) for energy density and diet analyses. These sites and years represented differences in available prey. In Lake Michigan, energy densities of deepwater sculpin in 2001 were similar to those reported in 1969–1971. In contrast, energy content declined at least 26% at Muskegon between 2001 and 2009. Overall, energy density was 31–34% higher at a site with abundant Diporeia spp. compared with two sites without Diporeia spp. Deepwater sculpin diets consisted primarily of M. relicta at all sites, but included 10–17% (dry mass) Diporeia spp. at sites where this crustacean was still abundant. Food biomass in stomachs was higher at sites with abundant Diporeia spp. than at those without Diporeia spp. Deepwater sculpin energy density and food biomass in stomachs were similar between two sites without Diporeia spp. despite differences in abundance of remaining prey, M. relicta. Declines in deepwater sculpin energy density suggest the potential for further effects on other species and changes in the flow of energy through the food web of the Great Lakes.