998 resultados para 178:61


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The rhythm of division of 9 species belonging to different groups of algae were analysed in situ and in the laboratory. The research which developed in different environmental conditions attempted to establish the capacity for multiplication and assimilation of chlorophyll on the part of the algae under study with a view to placing them in a culture. The results obtained showed that the green multicellular algae (eg. Ulothrix) and the blue algae (eg. Lyngbya, Oscillatoria) are able to produce an appreciable quantity of dry matter, just as the unicellular algae. At the same time it arises that amongst the numerous factors of the environment, temperature plays one of the most important roles in the process of multiplication.

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The determination of relative connections between families and genera of Cladocera, necessary for the construction of their natural systems, must be based on various criteria, among them on the structure of the ephippia. Of particular interest is the study of the process of formation and structure of the ephippium in Macrothricidae, different representatives of which differ significantly among themselves according to this criterion. In this article are presented the results of an investigation of the features of formation of the ephippium in seven species of Macrothricidae and in the moinid Moina weismanni Ishikawa (Moinidae).

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The present work is concerned with the processes of sand movement in the region of the Elbe estuary. In the first part the results of various investigations which have given indications of the regional transport directions are collected together. The interpretation of the results of a large number of continuous current recordings gives a picture of the resulting transport to be expected under the influence of the tides with those current conditions. This partial translation of the original paper provides the summary of this paper the regional distribution of the flood and ebb flow zones.

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There is at the moment no direct method of determining the organic matter content of natural waters. In 1940/41 8 different water bodies in central Russia were studied and their organic matter identified. The author concludes that there is currently no easy method to determine organic matter in water. A number methods need to be applied.

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Front cover. Table of Contents.

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Charles Darwin Foundation for the Galapagos Islands. Map.

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Contents: UNCSD: Rio+20. Shrimp Aquaculture in Central America. Sovereign Rights of Indigenous Fishers. Access to Fisheries Information. Harmonizing Fishworkers’ Rights. The Delhi MPA Workshop.

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There is apparently great scope for improvement of the design and operational aspects of the gear particularly for the effective exploitation of seasonal fisheries like that of seer, tuna, barracuda etc. In order to evolve improved, yet cheap trolling gear regular investigations were undertaken by the Craft & Gear Wing of the Central Institute of Fisheries Technology, off Cochin for five fishing seasons and the results of these studies are incorporated in this paper.

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光敏核不育水稻农垦58S是石明松于1973年在晚粳农垦58的大田中发现的雄性不育突变体,它在长日照下雄性不育可被用于与恢复系杂交生产杂种,而在短日照下雄性可育能用于自交繁殖,它的恢复系来源广泛。基于这些特性,育种学家用光敏核不育水稻建立的二系杂交水稻制种技术有很大的应用潜力。近十几年来,育种学家用农垦58S作基因供体转育了许多新的不育系,研究结果表明育成的粳型不育系均为光敏不育系,但在育成的籼型不育系中,绝大多数丧失光敏核不育特性,变成温敏不育系。目前因不知光敏核不育的分子遗传机制,尚不能解释这些问题。 本文用双向电泳技术分析了农垦58S和农垦58苗期和育性转换光敏感期叶绿体蛋白质的差异,在农垦58S中发现三个蛋白质(Pl,P2和P3),其中Pl和P2在苗期和光敏感期叶片内均存在,P3仅在光敏感期的叶片中存在,它们不受长日照或短日照处理的影响。农垦58没有这三个蛋白质。 用制备型双向电泳纯化后,得到SDS - PAGE和IEF纯的Pl和P2。经SDS-PAGE和IEF测定,Pl的等电点是6.2,分子量是41 kDa;P2的等电点是5.8,分子量是61 kDa。现称Pl为P41,P2为P61。氨基酸序列分析和同源性检索发现P41与水稻叶绿体ATP合成酶p亚基和酵母转录因子CAD1有同源性,此外,P41的N-端序列中有一个与蛋白激酶催化核心中的多功能motif Y-G-X-G-X- (P/T)-G-V相似的序列;P61的14个氨基酸长的N-端序列与水稻叶绿体ATP合成酶β亚基的一致。P41和P61 N-端前12个氨基酸的序列也完全一致。 PCR扩增和Southern杂交分析没有发现农垦58S和农垦58之间ATP合成酶β亚基基因(atpB)的多态性。Nothern杂交分析表明农垦58S中仅有一种、与农垦58 atpB mRNA分子量相同的atpB转录产物,但它的atpB mRNA丰度明显低于农垦58的。没有检测到突变的atpB和其它形式的atpB转录产物。 分析P41和P61在其它水稻材料中的分布特点发现它们在粳型光敏不育系7001S、5088S、31301S、C407S和1647S,籼型光敏不育系W7415S和W9451S以及温(光)敏不育系培矮64S中存在,而在对照材料三系水稻马协A、珍汕97A、马协B、珍汕97B和明恢63以及常规粳稻C94153中不存在。根据这些不育系的系谱和它们与农垦58S之间基因的等位性研究结果,讨论了P41和P61与光敏核不育性的可能联系。