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991.
992.
应用同源PCR技术,从被一种球状病毒感染的患病大菱鲆(Scophthalmus maximus)脾脏和肾脏组织中扩增出了一段长度为620bp的DNA片断。序列测定和Blast分析表明,该DNA片断与鱼类虹彩病毒主要衣壳蛋白(MCP)C末端编码区的DNA序列高度相似,由此证实感染养殖大菱鲆的这种球状病毒为一种鱼类虹彩病毒,暂命名为大菱鲆红体病虹彩病毒(TRBIV)。多序列比对和分析发现,TRBIV MCP C末端的205个氨基酸序列与GenBank中20种虹彩病毒相应序列的相似性分别为99.47%(韩国大菱鲆虹彩病毒)、97%~98%(待指定病毒属的7种病毒),以及50%以下(蛙病毒属、淋巴囊肿病毒属、虹彩病毒属的12种病毒),由此绘制出了包含TRBIV在内的21种虹彩病毒的系统发育树。研究结果表明,感染中国养殖大菱鲆的TRBIV属于虹彩病毒科待指定病毒属,位于该属ISKNV亚群和RSIV亚群之间,是该病毒属的一个新成员。 相似文献
993.
Keitaro Kato Masayoshi Takagi Yutaka Tamaru Shin-Ichi Akiyama Takafumi Konishi Osamu Murata Hidemi Kumai 《Fisheries Science》2007,73(2):440-445
ABSTRACT: Transgenic technology has been widely applied to a variety of freshwater fish species. However there are few reports on the use of this technology in commercially important marine species. In this study, the construction of expression vectors containing the β-actin promoter region for use in the red sea bream Pagrus major , a species of considerable importance to the aquaculture industry in Japan is reported. The β-actin gene was cloned from a red sea bream genomic DNA library. Recombinant plasmids were constructed by linking the 5' flanking region of the β-actin gene to the green fluorescent protein reporter gene, followed by the poly A signal sequence of simian virus 40 or the 3' flanking region the β-actin gene. Expression of these constructs was examined following microinjection into zebrafish and red sea bream embryos, and compared to that of the expression vector pXI-GFP driven by the Xenopus elongation factor 1α. The results indicated that the construct consisting of the β-actin 5'-and 3' flanking regions was the most efficacious. In future studies, it is planned to investigate the efficient condition for integration into chromosomes of the transgene. 相似文献
994.
Yoshifumi Sawada Manabu Hattori Naoko Sudo Keitaro Kato Yasuaki Takagi Kazuhiro Ura Michio Kurata Tokihiko Okada & Hidemi Kumai 《Aquaculture Research》2006,37(8):805-812
A previous study elucidated that an extreme hypoxia during somitogenesis induced the most frequent skeletal malformation centrum defects in red sea bream (RSB), Pagrus major. In this study, details of the hypoxic conditions to induce them in RSB, dissolved oxygen (DO) concentration and exposure time to hypoxia, were investigated. Fertilized eggs were exposed to seawater of six DO concentrations (0%, 10%, 25%, 50%, 75% and 100% of saturation) for seven different periods (5, 10, 30, 60, 120, 240 and 360 min) during somitogenesis. Somitic disturbances in newly hatched larvae were induced by exposure to 0% and 10% DO concentration for 10 and 120 min and longer respectively. Rearing eggs exposed to hypoxic condition of 10% DO for 240 min for 40 days post‐hatch showed that the location and the frequency of somitic disturbances in larvae and centrum defects in juveniles were significantly correlated (P<0.01). Dissolved oxygen concentration of the interstitial water in the egg high density layer formed at the water surface in a stationary state abruptly decreased to 3.7% within 7 min. Centrum defect induction by exposure of eggs to extreme low DO concentrations for a short period, which is the probable situation in the practical juvenile production, suggests that careful maintenance of DO concentration is important in the incubating water of fertilized eggs during egg sorting and transportation, where eggs are made into a pile and undergo hypoxia, for the prevention of centrum defects. 相似文献
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The northeast region of India, comprised of the states of Arunachal Pradesh, Assam, Manipur, Meghalaya, Mizoram, Nagaland,
Sikkim, and Tripura, is blessed with rich biodiversity and fisheries resources. With more than 90% of population being fish
eaters, there is heavy demand for fish but a wide gap exists between supply and demand. The region produces over 0.214 million
tons of fish annually, with almost 50% coming from aquaculture. Aquaculture development in the region is taking place at a
rapid rate. However, efforts are necessary to increase the present level of production through both horizontal and vertical
expansion. The region has rivers, coldwater streams, floodplain wet lands, reservoirs, lakes, ponds, paddy fields, and mini-barrages
to support large-scale aquaculture activities, which can not only produce fish to meet regional requirements, but also export
the surplus. This paper describes and discusses the current status of aquaculture, production level, constraints, and future
directions towards achieving “fish for all” in the region. 相似文献
999.
用十二烷酰肌氨酸盐抽提结合超速离心纯化,制备了19株典型嗜水气单胞菌(Aeromonas hydrophila)和1株温和气单胞菌(A.sobria)的主要外膜蛋白(MOMP)。根据SDS-PAGE图谱,将其中的14株菌分为3个MOMP组,I组的主要蛋白带为40kD和43kD,Ⅱ组的主要蛋白带为40kD和50kD,Ⅲ组的主要蛋白为40kD、46kD和50kD.MOMP组和血清型间没有严格的关系。用兔抗嗜水气单胞菌体抗原为第一抗体进行免疫印迹实验。结果显示,所有被试菌株都能产生强阳性反应,其中40kD的蛋白带为大多数菌株所共有,且具有相似的免疫原性,是构成菌体抗原的重要免疫原。用0.2mol/L甘氨酸缓冲液(pH4.0)处理上述菌株培养物,结果仅有嗜水气单胞菌ZY01-g3能够分离到丰富的S层样蛋白,其分子量约为52kD,而分子量约为52kD,而其他菌株未能分离到典型的S层样蛋白,表明S层蛋白的分布有限。 相似文献
1000.
- 1. Coral reefs around the world have been deteriorating over decades owing to anthropogenic pressure. In the Caribbean recent rates of decline are alarming, particularly for coral reefs under high local human impact, many of which are severely degraded, although regions with lower direct anthropogenic influence seem less affected.
- 2. Little Cayman is a relatively undeveloped island, with less than 150 permanent residents. About 20% of its reefs have been protected by no‐take marine reserves since the mid‐1980s. We analysed the dynamics of coral communities around the island from 1999 to 2004 in order to test the hypothesis that a lack of major local anthropogenic disturbances is enough to prevent decline of coral populations.
- 3. Live hard coral coverage, coral diversity, abundance, mortality, size, and prevalence of disease and bleaching were measured using the Atlantic and Gulf Rapid Reef Assessment methodology (line transects) at nine sites. Despite the apparent undisturbed condition of the island, a 40% relative reduction of mean live coral coverage (from 26% to 16%, absolute change was 10%) was recorded in five years. Mean mortality varied from year to year from 23% to 27%. Overall mean diameter and height have decreased between 6% and 15% on average (from 47 to 40 cm for diameter, and from 31 to 29 cm for height).
- 4. The relative abundance of large reef builders of the genus Montastraea decreased, while that of smaller corals of the genera Agaricia and Porites increased. Disease prevalence has increased over time, and at least one relatively large bleaching event (affecting 10% of the corals) took place in 2003.
- 5. Mean live coral cover decline was similar inside (from 29% to 19%) and outside (from 24% to 14%) marine no‐take reserves. No significant difference in disease prevalence or clear pattern in bleaching frequency was observed between protected and non‐protected areas. It is concluded that more comprehensive management strategies are needed in order to effectively protect coral communities from degradation.