BIOLOGICAL ASPECTS OF RESTING EGG FORMATION, DIAPAUSE AND HATCHING OF SMALL SPECIES ROTIFERS AND ITS APPLICATION TO MASS PRESERVATION TECHNOLOGY

在采集的20株轮虫中，8株具有有性生殖能力。在30℃、16 ppt的盐度条件下，混合率大于30%。夏威夷和兰卡威菌株的静息卵形成旺盛。高效液相色谱分析表明-氨基丁酸和5-羟色胺存在于轮虫体内，提示它们可能是轮虫的神经递质。我们利用从Koshiki菌株中获得的雄性配偶识别信息素多克隆抗体进行了多项检测。除Hamana和Spanish菌株外，抗体与其他菌株结合良好。当雌性与抗体结合时，不同菌株间雄性对雌性的配偶识别同样受到抑制。这表明，其他小种轮虫品系的污染不会降低种群中雄性配偶的认知度。利用夏威夷菌株和哈马纳菌株，在上述最佳条件下进行了静息蛋的批量生产。采用半连续培养法，可延长混合液的诱导时间。对于夏威夷菌株，在三个储罐中，每500升储罐的静息卵收获量分别为7、5和110万个（百万），而对于哈曼菌株，静息卵收获量分别为65、79和2700万个。静息卵冻干后在4℃下大量保存，孵化率50-60%。

Mechanism of resting egg formationAmong collected twenty rotifer strains, eight strains had sexual reproductive ability. These exhibited the percent mixis at more than 30% under 30℃ and 16 ppt salinity. Resting egg formation was vigorous with Hawaii and Langkawi strains. The HPLC analysis clarified that gamma-aminobutyric acid and 5- HT are present in rotifers, suggesting that these may function as neurotransmitters in rotifers. We conducted several assays using the polyclonal antibody of male mate recognition pheromone obtained from Koshiki strain. The antibody binded well with strains except Hamana and Spanish strains. Male mate recognition to females among strains were equally inhibited when females were bound with the antibody. These suggest that the contamination of other small-species rotifer strains will not reduce the male mate recognition in the population.Mass production and preservation of resting eggsUsing Hawaii and Hamana strains, we conducted mass production of resting eggs under optimal condition obtained above. Semicontinuous culture method was used to enhance the mixis induction for a longer period of time. For Hawaii strain, the resting egg harvest in three tanks were 7, 5 and 1.1 (million ) resting eggs per 500 liter tank, and it was 65, 79 and 27 million resting eggs for Hamana strain. Resting eggs were mass preserved at 4oC after lyophilization, and we obtained 50-60% hatching.