生物自生

The Cyanobacteria and soil bacteria such as Azotobacter, which carry out BNF without plant involvement, are examples of free-living nitrogen fixing organisms.

兰细菌和土壤细菌如固氮菌都是自生固氮微生物的代表，它们可以在没有植物介入下进行生物固氮。

To better understand the roles of LsrA protein in nodulation, a series of analyses of nodules using scanning electron microscopy, genetic and biochemical approaches have been carried out. Our analyses suggest that the lsrA1 nodules contain bacteroids in the invasion and establishing zone only. The lsrA gene expression is active early in the invasion zone and activated later than bacA genes. The lost of LsrA protein dramatically reduced the expression of nifA and fixK, and completely blocked the expression of the nifH gene for nitrogenase. LsrA protein functions early in the bacteroid development and it is essential for the development nitrogen fixing bacteroids.

前期的工作中，苜蓿中华根瘤菌Rm1021中90个候选LysR基因已经被定向插入突变，并筛选在自生生长时期、共生生长时期的表型，以期寻找更多在自生状态或共生固氮中有功能的LysR转录因子。1 针对前期鉴定出的共生固氮必需的lsrA基因，我们应用了一系列扫描电子显微镜技术、生物化学、分子遗传学等方法，发现lsrA基因主要在根瘤侵染区开始表达，表达时序也在侵染阶段左右，但晚于bacA基因表达；LsrA蛋白缺失后根瘤固氮区中缺乏具有固氮能力的类菌体，nifA和fixK基因的转录水平降低，nifH基因的转录被完全阻断，因此LsrA蛋白为根瘤发育所必需，是新的根瘤发育信号传导途径成员。2 通过表型筛选我们鉴定了苜蓿中华根瘤菌的oxyR基因，并研究了它的调节特性。oxyR突变后，苜蓿中华根瘤菌对过氧化氢敏感性提高，适应性降低。

It is shown that gas reservoirs described belong to large-scale self-generation and self-storage biogenetic gas and have good pool-forming conditions.

研究表明，该气藏属较大规模的自生自储型生物成因气，成藏条件良好。

The greatest amount of BNF by free-living nitrogen-fixing organisms may be in the flood waters of paddy rice production.

自生型固氮微生物进行的生物固氮量最大的可能是在淹水的水稻田里。

Amazingly, these mitochondria were once free-living bacteria that were captured by an early single-celled eukaryote.

令人惊奇的是，这些线粒体曾是被早期单细胞真核生物俘获的自生细菌。

A model proposing dual mechanisms for energy input into the oyster bed system through both filter-feeding oysters and benthic algae is presented.

综合上述实验资料其中显示能量输入牡蛎床生态系统有两个途径海水以牡蛎为介质，自海水中滤取有机分子形成生物浓缩后，再传递至海底海床系统：底藻(9～14公尺深处)在冬季及春初繁生而直接行光合作用导入能量。

With distance from the lake,the Aerxiaote lake vegetation happened converse succession.From outside to inside,the structure of plant community was gradually simple,biological diversity was shrinking and halophytic vegetation had decreasing tendencies.From outside to inside,there were Aneurolepidium dasystachys,Phragmites australis,Suaeda salsa L.community.Succession tendency was from wetland and typical grassland vegetation to salinization and desertization vegetation.

阿尔肖特湖边的植被随着距湖面距离及地形的不同，植被发生逆向次生演替，自外向内具有植物群落结构逐渐简单，生物多样性逐渐降低、盐生植物逐渐增加有规律性变化趋势；植被由外至内依次形成了赖草、芦苇、白刺和盐地碱蓬群落梯度，其演替趋势是由湿地和典型草原植被向盐碱化和荒漠化植被过渡。

Oral science as a member of biomedical science community cannot stand away from the trend. Hence GIOS is intended for building an access to advanced research of dental and oral science.

作为生医科学领域社群的一份子，生医材料暨生医工程的发展自无法独立於趋势之外，因此生医材料暨工程研究所生物物理暨组织工程学组之设立宗旨即在提供一个跨入口腔科学与生医工程进阶研究的机会。

The absorption and distribution of chromium were studied in ryeusing nutrient culture technique and pot experiment.

采用不同浓度K2CrO4(0，0.4，0.8和1.2 mmol/L)的Hoagland营养液处理黑麦幼苗，测定铬在黑麦体内的亚细胞分布、铬化学形态及不同部位的积累。

By analyzing theory foundation of mathematical morphology in the digital image processing, researching morphology arithmetic of the binary Image, discussing two basic forms for the least structure element: dilation and erosion.

通过分析数学形态学在图像中的理论基础，研究二值图像的形态分析算法，探讨最小结构元素的两种基本形态：膨胀和腐蚀；分析了数学形态学复杂算法的基本原理，把数学形态学的部分并行处理理念引入到家实际应用中。