Seasonal succession of Cladocerans in a ricefield in Italy

A biological ricefield in northern Italy, without periodic dry spells in its growing cycle and therefore more familiar to naturally humid zones, was studied for its heleoplankton community. The biocoenosis reached a greater level of complexity than reported in literature. In particular, the seasonal succession of Cladocerans, the dominant group throughout the study period, was analyzed. Wlassicsia pannonica (Daday, 1904; Anomopoda Macrothricidae), is new to Italy; its morphology is compared to that of other populations of the same species and its biological cycle is compared with that of other dominant Cladocerans.     

Hyaluronan in morphogenesis

Hyaluronan is a very large polysaccharide that is found in extracellular matrices, at the cell surface and inside cells. This review focuses on the functions of hyaluronan directly associated with the cell surface, where it is commonly present as the essential core of a highly hydrated pericellular matrix that contains several other components (hyaladherins) bound to hyaluronan. Three major molecular characteristics of hyaluronan contribute to its physiological functions: its unique hydrodynamic properties, its interactions with structural extracellular hyaladherins, and its instructive effects on cell signaling and behavior. Recent studies of hyaluronan-deficient mouse embryos illustrate the importance of each of these classes of function of hyaluronan. It is postulated that the morphogenetic effects of hyaluronan are due to its ability to act as a template for assembly of a multi-component, pericellular matrix as well as to its physical properties. This matrix would provide a hydrated environment in which cells are separated from structural barriers to morphogenetic changes and receive signals from hyaluronan itself and from associated factors.     

Lazarillo, a neuronal lipocalin in grasshoppers with a role in axon guidance

In this report we present a review on the grasshopper lipocalin Lazarillo with special emphasis on how its molecular properties could account for its known function: the guidance of pioneer neurons during nervous system development. The expression and function of Lazarillo in a subset of developing neurons, its heavy glycosylation and its glycosylphosphatidylinositol linkage to the plasma membrane, make Lazarillo a unique member of the lipocalin family. We have built a model of the tertiary structure of Lazarillo in which we have studied the exposed surfaces in search for clues about ligand and protein interactions with Lazarillo. Our hypotheses about how this lipocalin can exert its function are discussed.     

Metabolism of vitamin D3 administered in liposomes in rat liver]

Incorporation of [3H]-cholecalciferol into the liver and the rate of its conversion into 25-OH-D are significantly larger after intravenous administration of this vitamin into liposomes than its dissolution in ethanol. The latter may be due to a different distribution of vitamin D3 in the cells of the liver. Incorporation of [3H]-vitamin D3 in reticulocytes suggests that its cells are a locus for storage of vitamin D, from which the latter is transported into hepatocytes where its 25-hydroxylation proceeds.     

Villin function in the organization of the actin cytoskeleton. Correlation of in vivo effects to its biochemical activities in vitro.

Villin is an actin-binding protein of the intestinal brush border that bundles, nucleates, caps, and severs actin in a Ca(2+)-dependent manner in vitro. Villin induces the growth of microvilli in transfected cells, an activity that requires a carboxyl-terminally located KKEK motif. By combining cell transfection and biochemical assays, we show that the capacity of villin to induce growth of microvilli in cells correlates with its ability to bundle F-actin in vitro but not with its nucleating activity. In agreement with its importance for microfilament bundling in cells, the KKEK motif of the carboxyl-terminal F-actin-binding site is crucial for bundling in vitro. In addition, substitutions of basic residues in a second site, located in the amino-terminal portion of villin, impaired its activity in cells and reduced its binding to F-actin in the absence of Ca(2+) as well as its bundling and severing activities in vitro. Altogether, these findings suggest that villin participates in the organization and stabilization of the brush border core bundle but does not initiate its assembly by nucleation of actin filaments.     

玉米中植酸代谢研究的策略

作物尤其是玉米的种子中积累了丰富的植酸。早先的研究侧重于降低种子中植酸的含量,但是随着人们对植酸认识的深入,发现植酸对于动、植物而言具有不可替代的生物功能。对于人和动物而言,植酸有抗营养作用,但也是重要的健康因子;对于植物而言,植酸及其代谢中间体的生物学功能却缺乏明确的研究。若要明确把握植酸的育种方向,就必须对植酸在植物中的合成过程有明确的认识。但自植酸被发现至今,人们对于其在高等植物中的合成过程仍然知之甚少,对其生物学功能更是缺乏全面的了解。本文综述了植酸代谢研究的现状,分析并总结了植酸的代谢通路,指出了植酸代谢研究的突破点,结合植酸代谢的研究特点和进展,比较了基因同源克隆、关联分析等4种最具潜力的研究策略。     

蜂蜜中内源性物质苯甲酸的研究进展

蜂蜜是一种蜜蜂采集植物花蜜后酿制而成的天然甜味物质,具有丰富营养成分和多种生理活性功能。本文明确了苯甲酸是蜂蜜中天然存在的一种特征性风味物质,且含量与蜜源植物有关,并对其检测方法、形成机理、代谢途径和稳定性等进行了概述。最后,提出应深入细化蜂蜜等食品中苯甲酸形成机理的基础研究,不仅可针对性降低加工工艺导致的含量升高,更可为传统产业科技转型升级提供技术支持。     

Geobacillus研究进展

Geobacillus是国际上2001年新命名的一类细菌。由于其具有嗜热、兼性厌氧,降解烃和产生表面活性剂的特性,在微生物采油、环境治理等领域中有潜在应用价值;同时,这类细菌可能具有特殊的功能基因和特种酶,对构建工程菌亦具有重要的研究价值。对Geobacillus的研究历史、分类组成和生物学特性、生态分布及其分子生物学研究和应用进行了综述。     

Thermoregulatory mechanisms in Sarcophaga

Summary The flesh fly, Sarcophaga, is frequently seen feeding on flowers during periods of high radiation when other flies of comparable size avoid exposure because of the dangers of overheating. Sarcophaga is able to maintain its intermittent flower visits due to a cuticle of high thermal reflectance, giving low intrinsic heating rates, and to an ability to shunt blood between thorax and abdomen according to its needs. The fly thus achieves partial thermoregulation and can keep its body temperature within the preferred range for longer periods than its potential entomophilous competitors.     

Participation of the substantia innominata in differential inhibition in the cat

Elaboration of differentiation, its disturbance resulting from bilateral lesion of the substantia innominata and its subsequent restoration was studied in cats. Ablation of the substantia innominata was accompanied by disturbances of the internal inhibition. The initial level, that before the operation, was not obtained even after a long training. It is suggested that substantia innominata modulates cortical activity and its ablation prolongs the afferent synthesis.     

点柄乳牛肝菌研究进展

点柄乳牛肝菌（Suillus granulatus）味道鲜美营养丰富,并具有良好的药用活性,是广受欢迎的野生食药用菌。从分类学、发生规律、药用活性、与植物关系及驯化研究方面系统阐述了点柄乳牛肝菌的现状,并对其未来发展及应用进行了展望。     

Mucopolysaccharide Which Regulates Growth in Neurospora

Neurospora produces a mucopolysaccharide (called MP) which inhibits its growth, causes vacuolation and agglutination of its cells, and precipitates its purified membrane protein. Cultures of a colonial strain display a phase of slow growth; the induction of this phase is traced to the production of MP by the mold. Stationary-phase cultures of wild type also produce MP. MP is a polymer of galactosamine, its amino groups only partially acetylated, probably containing other minor components. MP molecular weight is approximately 10(6). Complete acetylation abolishes the biological activities of MP. It is suggested that the regulatory effect of MP is mediated by its interaction with the protoplasmic membrane.     

基因工程（核）雄性不育小麦研究展望

基因工程是创造核雄性不育基因的一个新途径。通过综述大量资料,探讨了利用基因工程创造雄性不育的机制,并论述了其在小麦上应用的可能性及发展前景。     

Serotonin metabolism in thrombocytes and microvascular hemostasis in spontaneous arterial hypertension

Serotonin content and accumulation in platelets and its release from them, as well as changes in thrombus formation in mesenteric arterioles and venules of the small intestine have been investigated in control rats and rats with spontaneous hypertension (SHR). Serotonin accumulation in platelets was determined upon its incubation with platelets. Disodium ADP salt was used as an inductor of release. Laser-induced thrombosis was caused by microvessels exposure to impulse laser irradiation. The control animals revealed a significant difference between the initial serotonin platelet level and serotonin level upon incubation and release; in values, the values of basic thrombus-forming parameters were higher than in arterioles. In SHR there is a decrease in biogenic amine content in platelets, a depression in its accumulation and release, an increase in the time of thrombus growth, its size up to the separation of the first embolus and its length along the vascular wall. It is concluded that spontaneous hypertension is characterized by decreased functional activity of platelets and depressed resistance of arterioles and venules to thrombus formation.     

基于16S rDNA基因的中国部分地区非B型烟粉虱系统发育关系分析

【目的】烟粉虱Bemisia tabaci是一个快速进化的复合种。由于近年来烟粉虱危害不断增加, 其生物型问题也越来越受到关注。在我国, 不仅存在危害严重的B型烟粉虱, 同时也已发现多种非B型烟粉虱。通过鉴定我国部分地区目前发生的烟粉虱生物型种类, 分析它们与世界各地不同生物型之间的关系, 可为我国烟粉虱的生物型检测和综合防治提供依据。【方法】利用16S rDNA基因作为分子标记, 鉴定了2005年与2006年在我国6个省份（自治区）采集的22个非B型烟粉虱样本的生物型, 并探讨了各生物型之间的系统进化关系。【结果】所研究的22个非B型烟粉虱归属于Q型、Nauru型和An型, 3种生物型之间的遗传距离在10%以上, 但是Q生物型与B生物型之间的亲缘关系最近, 遗传距离在2.8%~4.0%范围内; 进化分歧数据还表明, 不同生物型之间的遗传距离明显大于同一生物型内遗传距离, 其中Q型内部差异最小, 在0.9%以内; 同时结果表明目前在我国多个生物型共同存在是一个普遍的现象, 其中Nauru型的分布较广泛; 在云南地区检测到的非B型烟粉虱生物型类型最多。【结论】烟粉虱生物型遗传分化复杂, 利用16S rDNA基因能有效鉴定烟粉虱的生物型。     

昆虫延长滞育的研究

持续时间达1年以上的滞育,称为延长滞育,延长滞育的诱导、维持、解除均不同于简单滞育(滞育期短于1年)。本论文系统阐述了昆虫延长滞育的类型、滞育诱导及解除的环境因子、延长滞育物候学和生物学特性,延长滞育的遗传学及延长滞育的生态学意义。延长滞育是昆虫生活史的重要组成部分,是一种普遍现象。     

姬松茸的研究与进展

概述了大型真菌姬松茸的生物学特性、保健功能以及近年来的研究进展,并对其主要功效物质如多糖等成分、姬松茸深层发酵技术的现状和菌丝体应用情况作了介绍。     

肝素结构与功能的研究进展

肝素是一类结构异常复杂的糖胺聚糖,与此相对应的是其多种生物学功能。除了经典的抗凝血及其相关的抗血拴生成以外,肝素还具有抗平滑肌细胞增殖、抗炎症、抗肿瘤及抗病毒等,并且这些生物活性同抗凝活性无关,而同肝素的特异结构密切相关。本文综述了肝素的多种生物学功能、作用机制及结构与功能的关系。     

Autophagy: in sickness and in health

The degradation of intracellular components in lysosomes (autophagy) has recaptured the attention of cell biologists in recent years. The main reason for this renewed interest is the dissection of the molecular machinery that participates in this process, because the identification of new intracellular elements involved in autophagy has provided new tools to trace, quantify and manipulate autophagy in a growing number of organisms. As a result, a better understanding of the physiological roles of autophagy, the consequences of its malfunctioning and its participation in different pathological processes has emerged. This article reviews our current knowledge of the role of autophagy in disease and the efforts to reconcile its proposed dual function as both a cell protector and a cell killer.     

湖南会同林区杉木人工林呼吸量测定

对杉木人工林的CO2排放动态和杉木各木质器官呼吸量进行了测定,结果表明,杉木树干呼吸的季节变化规律为3~7月份随着树木生长和气温的升高,树干呼吸呈上升的趋势,在7月份达年呼吸速率的最大值,CO2为0.376m g/(m3.m in)。8月至12月呈逐渐递减的趋势,在1~3月份树干呼吸基本上维持在一定数值上,并且杉木树干呼吸在杆材生长时期随着年龄的增大而减小;杉木树干呼吸的日变化规律为:一天中杉木树干呼吸基本上是随着温度升高而增大,随着温度降低而减小,中午前后出现午休现象。在杉木树干呼吸日变化曲线中出现两次高峰期,一次是在12:00~16:00时,另一高峰出现在24:00。根据测出的有关参数,用积分方法推导出杉木树干、树枝和树根的年呼吸量CO2分别为9.67t/(hm2.a)、2.21 t/(hm2.a)和2.12t/(hm2.a),结合叶片呼吸速率测定,计算出杉木林年呼吸量CO2为21.523 t/(hm2.a),其中,叶片年呼吸量CO2为7.523t/(hm2.a)。并初步确定杉木树干的维持呼吸占年呼吸的39.7%。