Participatory research in giant clam farming

Research into developing farming methods for giant clams at the ICLARM Coastal Aquaculture Centre in the Solomon Islands has proceeded in parallel with a program of village-based trials. This program is an attempt to involve the envisaged recipients of technology at a very early stage. The considerations, design and initial implementation of this program from 1988 to 1990 are described in this article. The expansion, impact and results of the program will be the subject of future publications by the scientists involved.

Genetic diversity in wild stocks of the giant freshwater prawn (Macrobrachium rosenbergii): implications for aquaculture and conservation

The giant freshwater prawn (Macrobrachium rosenbergii) is cultured widely around the world but little is known about the levels and patterns of genetic diversity in either wild or cultured stocks. Studies have suggested that genetic diversity may be relatively low in some cultured stocks due to the history of how they were founded and subsequent exposure to repeated population bottlenecks in hatcheries. In contrast, wild stocks have an extensive distribution that extends from Southern Asia across Southeast (SE) Asia to the Pacific region. Therefore, wild stocks could be an important resource for genetic improvement of culture stocks in the future. Understanding the extent and patterns of genetic diversity in wild giant freshwater prawn stocks will assist decisions about the direction future breeding programs may take. Wild stock genetic diversity was examined using a 472 base-pair segment of the 16S rRNA gene in 18 wild populations collected from across the natural range of the species. Two major clades ("eastern" and "western") were identifi ed either side of Huxley’s line, with a minimum divergence of 6.2 per cent, which implies separation since the Miocene period (5-10 MYA). While divergence estimates within major clades was small (maximum 0.9 per cent), evidence was also found for population structuring at a lower spatial scale. This will be examined more intensively with a faster evolving mtDNA gene in the future.

Development of giant freshwater prawn broodstock

The commercial success of a giant freshwater prawn (Macrobrachium rosenbergii) hatchery depends upon the uninterrupted supply of the desired quantity and quality of broodstock. This study was an attempt to develop the broodstock near a hatchery, to be used for seed production throughout the year. The hatchery produced seed were stocked at the rate of 3/m2 after initial pond preparation. The prawns were fed with a pelleted diet (3 mm size) prepared by using locally available feed ingredients. The seed had an initial weight of 0.30 g and attained an average weight of 92.0 g and 62.0 g in males and females, respectively, within 11 months. Berried prawns were observed starting from the month of June (5%), after six months of stocking, with a maximum in September (60%). The percentage of berried prawns increased from June to September when the water temperature was optimum and decreased from December when it got cold. The broodstock developed in this experiment could be used in the hatchery after six months of stocking, and brooders could be used to produce seed for two seasons before being sold in the market.

Who's working on giant clam culture?

An examination is made of the literature on giant clam (Tridacna ) culture methods induced spawning, larvae, larval and post-larval rearing and socioeconomics. ASFA and the ICLARM library and professional staff collections were used for the search.

大车前（Plantago major L. "Giant Turkish."）体外优化再生体系的建立及Na+/H+逆向转运蛋白基因SeNHX1 和TtNHX1 的功能鉴定

大车前（Plantago major L. "Giant Turkish."）不仅有很高的药用价值，在生态学研究方面也是重要模式植物。大车前的组织培养工作，目前报道很少。对其组织培养体系的建立，为筛选大车前耐盐突变体和基因转化建立高效的体外再生系统和实验平台体系。通过愈伤组织诱导和直接不定芽再生途径， 建立了大车前（Plantago major L. "Giant Turkish."）的快速高效再生系统。叶片外植体在含有1.0 mg/L NAA的MS培养基中培养3周后，形成愈伤组织，愈伤组织在含4.0 mg/L 6-BA的MS培养基中成功再生，得到完整植株。种子外植体在含0.2 mg/L IAA和1.0 mg/L TDZ的MS培养基中培养4周后产生大量的丛生芽，对9株再生植株进行RAPD检测表明，部分植株在DNA水平上发生了变异。 植物抵御盐胁迫的一个重要机制是在液泡中积累Na+，从而使细胞质内Na+保持在较低水平，并且降低细胞渗透势。Na+运输到液泡是由液泡Na+/H+逆向转运蛋白完成的。本实验室已从盐生植物盐角草（Salicornia europaea）和番杏（Tetragonia tetragonioides）中分别克隆得到SeNHX1和TtNHX1基因。本文研究了SeNHX1和TtNHX1基因在酵母突变体里的作用。TtNHX1和SeNHX1蛋白在缺陷型酵母菌株里的表达能够提高这些菌株对NaCl、LiCl和潮霉素的抗性，提高到与野生型相当的抗性水平。说明TtNHX1和SeNHX1有着与酵母ScNHX1相似的细胞定位和作用机制，是ScNHX1的功能类似蛋白。