Bindin from a sea star

SUMMARY The genetic basis for the evolution of development includes genes that encode proteins expressed on the surfaces of sperm and eggs. Previous studies of the sperm acrosomal protein bindin have helped to characterize the adaptive evolution of gamete compatibility and speciation in sea urchins. The absence of evidence for bindin expression in taxa other than the Echinoidea has limited such studies to sea urchins, and led to the suggestion that bindin might be a sea urchin-specific molecule. Here we characterize the gene that encodes bindin in a broadcast-spawning asterinid sea star ( Patiria miniata ). We describe the sequence and domain structure of a full-length bindin cDNA and its single intron. In comparison with sea urchins, P. miniata bindin is larger but the two molecules share several general features of their domain structure and some sequence features of two domains. Our results extend the known evolutionary history of bindin from the Mesozoic (among the crown group sea urchins) into the early Paleozoic (and the common ancestor of eleutherozoans), and present new opportunities for understanding the role of bindin molecular evolution in sexual selection, life history evolution, and speciation among sea stars.     

Fine-scale adaptation in a clonal sea anemone

Local adaptation in response to fine-scale spatial heterogeneity is well documented in terrestrial ecosystems. In contrast, in marine environments local adaptation has rarely been documented or rigorously explored. This may reflect real or anticipated effects of genetic homogenization, resulting from widespread dispersal in the sea. However, evolutionary theory predicts that for the many benthic species with complex life histories that include both sexual and asexual phases, each parental habitat patch should become dominated by the fittest and most competitive clones. In this study we used genotypic mapping to show that within headlands, clones of the sea anemone Actinia tenebrosa show restricted distributions to specific habitats despite the potential for more widespread dispersal. On these same shores we used reciprocal transplant experiments that revealed strikingly better performance of clones within their natal rather than foreign habitats as judged by survivorship, asexual fecundity, and growth. These findings highlight the importance of selection for fine-scale environmental adaptation in marine taxa and imply that the genotypic structure of populations reflects extensive periods of interclonal competition and site-specific selection.     

“精制多价抗海蛇血清”的制作

目的　海蛇均为前沟牙毒蛇 ,分布于太平洋及印度洋沿岸 ,大西洋没有海蛇。中国产海蛇 1 6种 ,分布于北起辽宁、南至海南及广西沿海 ,分布较广、数量较多及蛇伤发病率较高的海蛇为青环海蛇( H ydrophis cyanocinctus)和平颏海蛇( Laticauda semifasciata)。调查结果表明 ,被海蛇咬伤如不及时处理 ,通常有 50 %的患者死亡。在中国广西北海市每年均有被海蛇咬伤中毒致死的病例。为研制中国、日本及东南亚沿海国家主要有毒海蛇青环海蛇和平颏海蛇咬伤的有效治疗药“多价抗海蛇毒血清”,填补急救医学空白。　　方法　从中国北部湾产青环海蛇和平…     

Pelagic sea snakes dehydrate at sea

Secondarily marine vertebrates are thought to live independently of fresh water. Here, we demonstrate a paradigm shift for the widely distributed pelagic sea snake, Hydrophis (Pelamis) platurus, which dehydrates at sea and spends a significant part of its life in a dehydrated state corresponding to seasonal drought. Snakes that are captured following prolonged periods without rainfall have lower body water content, lower body condition and increased tendencies to drink fresh water than do snakes that are captured following seasonal periods of high rainfall. These animals do not drink seawater and must rehydrate by drinking from a freshwater lens that forms on the ocean surface during heavy precipitation. The new data based on field studies indicate unequivocally that this marine vertebrate dehydrates at sea where individuals may live in a dehydrated state for possibly six to seven months at a time. This information provides new insights for understanding water requirements of sea snakes, reasons for recent declines and extinctions of sea snakes and more accurate prediction for how changing patterns of precipitation might affect these and other secondarily marine vertebrates living in tropical oceans.     

Differences in susceptibility to sea lice infection between a sea run and a freshwater resident population of brown trout

Two experimental groups comprising mixed Norwegian sea run and freshwater resident brown trout Salmo trutta were infected with sea lice Lepeophtheirus salmonis in replicate tanks. Comparison of mean abundance and louse development between the sea run and resident groups revealed highly significant differences in lice abundance. The resident trout had an average abundance ± of 6·3±0·37 and 6·6±0·43 lice whilst the sea trout had an average abundance of 3·5 ±0·25 and 3·3 ±0·28 lice 29 days post infection at 9° C. No differences in development of lice, of either sex, were detected between the groups. As host groups were naive to sea lice at the start of the experiment, this suggests that there was a significant difference in susceptibility to sea lice infection between them, which may be genetically determined.     

Habitat use and dispersal of post-smolt sea trout Salmo trutta in a Scottish sea loch system

Post-smolt anadromous brown trout Salmo trutta , sea trout, from two Scottish west coast rivers, the Balgy and Shieldaig, flowing into adjacent sea lochs were tracked simultaneously using arrays of moored acoustic receivers to determine dispersal patterns and loss rates. Fish tended to stay close to their natal rivers for the first 14 day after entering the sea, during which time about half the fish were lost to the study. Although initially the overall pattern of dispersal was similar for individual fish from both rivers, towards the end of the study the groups had converged into one of the loch basins. There were also pronounced individual differences in habitat use with all those fish detected for >42 days exhibiting different patterns of habitat use. Loss rates were similar between the two rivers despite differences in the range of air-breathing predators to which the fish were initially exposed. These findings suggest that any management of predators or other mortality agents should be targeted towards mouths of rivers during and immediately following smolt emigration.     

Purification and characterization of a sea squirt beta-galactosidase

A beta-galactosidase was extracted from the internal organs of a sea squirt, Styela plicata, and purified 959-fold, with an 18% yield, by successive gel chromatography, anion-exchange chromatography, chromatofocusing, and affinity chromatography on a Con A-Sepharose column. The purified enzyme was fairly homogeneous, as judged on disc PAGE, SDS-PAGE, and gel chromatography on a Sephadex G-200 column. The molecular weight of the enzyme was estimated to be 77,000 and 75,000 by gel chromatography and SDS-PAGE, respectively, and its isoelectric point was determined to be 4.9 by the isoelectric focusing method. The enzyme was substantially stable in the pH range of 3.5 to 7.5, the optimum pH being 4.0. The enzyme was significantly inhibited by 9 mM HgCl2 and 9 mM DFP, while the inhibition by 0.9% PCMB was only 60% at 0 degrees C for 30 min. The purified beta-galactosidase apparently liberated galactose from a sea squirt antigen (H-antigen), two allergenically active glycopeptides (Gp-1 and Gp-2) derived from another sea squirt antigen (Gi-rep), asialo-ovomucoid glycopeptide, asialo-fetuin glycopeptide, GA1, CDH, and an ABEE-derivative (Gal beta 1----3ThrNAc-ABEE) of Gal beta 1----3GalNAc-ol isolated from bovine submaxillary gland mucin.     

Energetics of swimming of a sea turtle.

Young (mean mass 735 g) green turtles (Chelonia mydas) were able to swim in a water channel at sustained speeds between 0-14 and 0-35 m.s-1. Oxygen consumption at rest was was 0-07 l.kg-1.h-1; at maximum swimming speed oxygen consumption was 3-4 times greater than at rest for a given individual. In comparison with other animals of the same body mass the cost of transport for the green turtle (0.186lO2.kg-1.km-1) is less than that for flying birds but greater than that for fish. From drag measurements it was calculated that the aerobic efficiency of swimming was between 1 and 10%; the higher efficiencies were found at the higher swimming speeds. Based upon the drag calculations for young turtles, it is estimated that adult turtles making the round-trip breeding migration between Brazil and Ascension Island (4800 km) would require the equivalent of about 21% of their body mass in fat stores to account for the energetic cost of swimming.     

深层海洋浮游植物研究综述

对深层海洋(200 m)浮游生物的研究是我国海洋浮游生物研究的前沿,已有的深层海洋浮游生物知识是我国相关研究的基础。浮游植物需要阳光进行光合作用,大多数浮游植物沉降到深海中会死亡,但有些浮游植物却能在深海中生存。综述深层海洋中存活的浮游植物的研究进展,为我国的研究提供参考。在深层海洋发现的浮游植物(2"m)种类不多,共有18种,最深分布在4000 m,颗石藻的丰度大于硅藻和甲藻,最大丰度为2220个/L,出现在500 m。在1911—1985年期间,曾经发现橄榄绿细胞,由于研究手段有限,一直没有对其进行分类学研究。1985年以后的研究怀疑这些橄榄绿细胞就是聚球藻蓝细菌,聚球藻蓝细菌在太平洋、大西洋和地中海的几个站位能分布到2750 m,在深层海洋的最大丰度为3.5×105个/mL,出现在800 m。在许多海区200—700 m发现有浮游植物色素荧光的高值,但对引起高值的原因尚不清楚。浮游植物生物量在深层海洋的垂直剖面研究不多,已有的研究表明浮游植物生物量在300 m以深为0.001—0.1"g C/L,且其随深度增加而降低。