荧光原位杂交技术在医学微生物学中的应用

以16S rRNA 为靶序列的寡核苷酸探针荧光原位杂交技术已广泛应用于分析复杂环境中的微生物群落构成,包括监测和鉴定病原微生物以及未被培养微生物．通过对临床样品中微生物细胞的检测能提供微生物在人体中的种类、数量和空间分布等信息．其结果快速准确,较之传统的病原微生物诊断方法具有明显的优越性,在临床应用中有广泛的前景．     

分子生态学方法在微生物多样性研究中的应用

现代的核酸技术正在给生物学的研究带来新的革命,它使人们对于生命现象的研究更为深人,成为揭示生物科学规律的有力手段。自１９８５年Ｐａｔｅ等以核酸测序技术研究微生物的生态和进化问题以对］,对微生物多样性的研究进入了一个新阶段．以往对微生物的认识基于对微生物的培养和纯种分离技术,而在自然环境中的微生物９９．５％～９９．９％的种类至今尚是不可培养的［‘］,成为正确认识微生物生态系的严重障碍。分子生态技术的应用克服了培养技术的限制,对样品进行客观的分析,更精确地揭示微生物种类和遗传的多样性。因此,该技术与…     

土壤微生物多样性研究方法

概述了研究土壤微生物多样性的主要方法．传统上,土壤微生物群落的分析依赖于培养技术,使用各种培养基最大限度地培养各种微生物群体,但仍只能培养和分离出一小部分土壤微生物群落．使用Biolog分析、磷脂脂肪酸分析和核酸分析等方法,可研究和表征那些现在还不能够被培养的土壤微生物。从而获取关于土壤微生物群落多样性的更多和更完整的信息．     

鸡粪对铜污染土壤微生物生物量碳的影响

采用室内恒温好气培养法,研究了2．0％、4．0％、6．0％添加量鸡粪对铜污染土壤微生物生物量碳的影响。结果表明：向土壤中施入2．0％、4．0％、6．0％的鸡粪后,有机碳总量比对照分别增加了0．85、1．49、2．04倍,而可浸提有机碳含量分别增加了3．13、5．70、8．23倍,鸡粪的添加促进了土壤可浸提有机碳含量的增加,土壤可浸提有机碳含量和鸡粪添加量呈正相关（r=0．994^＊＊,n=12）。各处理土壤有机碳和可浸提有机碳含量随培养时间逐渐下降,90d后有机碳含量趋于稳定;土壤可浸提有机碳含量120d后趋于稳定。鸡粪显著促进了土壤微生物生物量碳含量和土壤微生物商的增加（P〈0．01）,与对照相比,2．0％、4．0％和6．0％鸡粪处理土壤微生物生物量碳含量分别增加2．88、5．19、6．98倍,土壤微生物生物量碳（SMBC）含量和土壤微生物商（SMQ）都与鸡粪的添加量呈正相关（rSMBC=0．998^＊＊,rSMQ=0．858,n=12）。在培养过程中士壤微生物生物量碳与土壤微生物商都呈现先下降再升高再下降的趋势。在培养试验的早期,鸡粪的添加有利于缓解铜污染土壤微生物生物量碳的下降,添加鸡粪的处理在培养的第10d后土壤微生物生物量碳含量开始上升,而对照则在30d以后才开始上升;添加鸡粪的处理在培养前期微生物生物量碳的最大下降幅度分别为：2．0％处理（52．74％）、4．0％处理（45．92％）、6．0％处理（55．52％）,而对照的下降幅度为92．02％。培养后期添加鸡粪处理土壤微生物生物量碳仍保持较高的水平。     

肠道微生物菌株资源库的构建与应用开发

肠道微生物组在组成和功能上都具有极高的复杂性,大量基于免培养的微生物组学研究表明肠道菌群失调与多种疾病都存在密切关联,肠道菌群的稳态与宿主健康密切相关已是共识。同时,越来越多的研究者认识到,可培养微生物菌株资源是肠道微生物组研究从关联分析向功能验证、机理解析和应用开发方向深入发展的基础和保障。本文主要对近年来完成的一些具有代表性的人肠道微生物大规模分离培养和菌株资源库构建工作,进行整理,总结回顾肠道微生物分离培养技术和方法的进展;并通过几个有代表性的基于可培养微生物菌株资源开展的肠道微生物数据挖掘、宿主–微生物互作机理研究和应用开发的成果,展示肠道微生物菌株资源库的应用价值和开发潜力。     

口腔未培养微生物分离培养策略的研究进展

口腔微生物是人体微生物组的重要组成部分,其群落组成丰富且独特。现有研究显示,口腔微生物与龋病、牙周炎等口腔健康问题有直接的联系,因而具有重要的研究价值。随着高通量测序技术的发展,人们对口腔中未培养微生物多样性的认识不断加深,这进一步催生对微生物分离培养技术需求的增加。为此,本文将围绕口腔未培养微生物及其分离培养策略的研究进展,首先介绍口腔中未培养微生物的研究现状;其次分析口腔微生物分离培养中可能的限制因素;最后综述微生物分离培养技术发展及其在口腔未培养微生物研究中的应用。全文旨在为口腔未培养微生物的分离培养提供思路和技术参考。     

油藏微生物群落研究的方法学

油藏微生物群落的解析和认知是开发和应用微生物采油技术的基础。利用各种提高油藏微生物可培养性的方法和非培养技术解析不同油藏微生物的群落结构、功能和多样性,对定向调控油藏微生物群落、开发和应用有效微生物驱油技术具有重要的指导意义。通过调查新近发展的提高微生物可培养性的方法和措施以及不依赖于培养的分子微生物生态学技术,总结了油藏微生物群落研究方法学的最新进展。提高微生物可培养性的方法和措施主要通过模拟微生物的生存环境,减少富营养的毒害作用、添加信号分子维持微生物细胞间的作用和提供新型电子供体和受体等手段采用稀释法、高通量培养法等方法得以实现;不依赖于培养的分子微生物生态学技术主要包括荧光原位杂交、末端限制性片断长度多态性分析、变性梯度凝胶电泳和构建克隆文库等技术。这些方法学的进展为更有效的获得各种油藏微生物资源、调控油藏微生物群落以提高石油采收率提供理论指导。     

极端嗜酸硫杆菌高密度培养的研究进展

极端嗜酸硫杆菌属微生物在生物冶金、生物脱硫以及固体废弃物的处置中扮演重要作用,但该类微生物在培养过程中细胞浓度很低,限制了该类微生物的广泛应用。高密度培养是提高微生物生产效率的有效手段。高密度培养技术在嗜酸微生物中的应用能够显著减少微生物培养的生成成本,缩短生产周期,极端嗜酸硫杆菌微生物菌剂的输出速率。本文从菌种选育、培养条件、培养方式综述了极端嗜酸硫杆菌高密度培养的研究现状。     

微生物的混合培养

混合培养是指人工建立微生物区系,利用两种或两种以上的微生物不同特性,加以调节控制,以达到所需目的的技术。这种技术在几千年以前,虽没有被认识,但早已得到应用。在十八世纪末,Rober-koch(1943—1910年)建立纯培养体系之前,凡是利用微生物的过程都是混合培养。纯种培养是指在特定环境中,仅存在一种微生物的生长。现在基础理论的研究,微生物技术的应用、工业发酵及优良菌株的选育等都是建立在纯培养的基础之上。纯培养奠定了     

秸秆预处理对土壤微生物量及呼吸活性的影响

冬小麦秸秆经8．0g·L^-1H2O2(pH11．0)溶液、12．5g·L^-1 NaOH溶液或H2SO4溶液浸泡8h并80℃烘干后,与无机N一起加入土壤,进行室内25℃恒温培养试验,在不同时间测定土壤微生物量C、N和CO2释放速率。结果表明,培养前期,秸秆预处理使土壤微生物量C数量增加了1．0～1．4倍,但降低了土壤微生物的呼吸活性;培养后期,NaOH和H2SO4处理使土壤微生物量C分别下降了28％和42％,但增加了土壤微生物的呼吸活性;H2O2处理则使土壤微生物量N增加90％;土壤微生物区系中的真菌比例在不同时刻有所增加,表明将秸秆预处理后施入土壤,将对土壤中微生物数量和呼吸活性产生一定影响。     

Seasonal distribution and abundance of tsetse flies (Glossina spp.) in the Faro and Deo Division of the Adamaoua Plateau in Cameroon

Ten years after the large-scale tsetse control campaigns in the important cattle rearing areas of the Faro and Deo Division of the Adamaoua Plateau in Cameroon, the seasonal distribution and abundance of tsetse flies (Glossina spp.) were determined. During a period of 12 consecutive months (January-December 2005), the tsetse population was monitored along four trap transects consisting of a total of 32 traps and two flyround transects traversing the study area, which comprised the tsetse-infested valley, a buffer zone and the supposedly tsetse-free plateau. Throughout the study period, a total of 2195 Glossina morsitans submorsitans and 23 Glossina tachinoides were captured in the traps and 1007 G. m. submorsitans (78.8% male flies) were captured along the flyround transects. All G. tachinoides and almost all G. m. submorsitans were captured in the valley. Five G. m. submorsitans were captured in traps located in the buffer zone, whereas no flies were captured in traps located on the plateau. The index of apparent abundance (IAA) of G. m. submorsitans was substantially higher in the areas close to game reserves. In the remaining part of the valley, where wildlife is scarce and cattle are present during transhumance (dry season), the IAA of tsetse was substantially lower. In this part of the valley, the abundance of tsetse seemed to be associated with the presence of cattle, with the highest IAA during transhumance when cattle are present and the lowest apparent abundance during the rainy season when cattle have moved to the plateau. It is concluded that the distribution of tsetse in a large part of the valley undergoes substantial seasonal changes depending on the presence or absence of cattle. The repercussions of those findings for the control of tsetse in the valley and the probability of reinvasion of the plateau are discussed.     

Échinodermes de l'Ordovicien supérieur (Ashgill) de Sardaigne et d'Algérie

Research on the influence of sea level variations on the benthic faunas have been carried out in the Upper Ordovician of Sardinia. Study of the depositional facies and sequence analysis of the upper part (Lower Ashgill) of the Portixeddu Formation led to the identification of the sedimentary environments. Cystoids and crinoids are associated to bryozoans and brachiopods in most levels. The numerical analysis of associations and megaguilds shows that crinoids and cystoids have a higher frequency in the proximal and median facies of the upper offshore. The columnal association characterized by Conspectocrinus celticus and the coronoid Mespilocystites tregarvanicus has been discovered in the upper part of the formation. This material and complementary samples from Upper Ordovician of Sardinia and Kabylia (Algeria) bring additional data on the systematic and show the wide distribution of this fauna outside of the Ibero-armorican domain. The distribution of this echinoderm association supports a palaeogeographical position of the Ibero-armorican domain and Sardinia within the north gondwanan margin during the Lower Palaeozoic.     

An Ultrastructural Study on the Development of Egg- apparatus in Rice Embryo Sac

The development of the egg-apparatus (consisted of an egg cell and two synergids) of rice ( Oryza sativa L. ) was studied at the uhrastructural level. The walls of the egg cell and synergids, immediately after their formation, possessed numerous plasmodesmata. Plasmodesmata were also present on walls between the egg cell and synergids. During the enlargement phase of the egg cell and synergids, the walls at the tip region began to loosen and vesiculate. By the time the embryo sac became mature, the part of the wall of the egg cell and synergids, facing the chalaza, disappeared. Consequently, the tip regions of the egg cell and synergids were only protected by a plasma membrane. When the embryo sac reached full maturity, the upper and middle region of the wall of the synergids broke up into pieces. At that time one synergid began to degenerate. Plasmodesmata persisted at the hook region of the wall of both the egg cell and synergids. Most plastids in the egg cell contained starch grains that persisted throughout the period of the embryo sac development. Starch grains in the plastids of the synergids appeared only before the time when the two polar-nuclei moved into the region above the egg-apparatus. They then disappeared and did not appear again until the embryo sac had reached full maturity. The size and location of the vacuoles in the egg cell were different from those in the synergids. The time of formation was also different. Vacuoles in the egg cell formed late in comparison with the synergids. Vacuoles in the chalazal region of the egg cell (especially at the early stage of the embryo sac development) were much larger than those in the micropylar region. Vacuoles in the synergids tended to concentrate mainly in the chalazal region. There was a peak period of lipid formation in the two synergids. The peak appeared when the embryo sac neared maturity. At the early stage of development, the nuclei of the synergids were elliptical in shape and were situated at the central region near the micropyle. The shape of the nuclei at the late stage of development became less regular and tended to move more towards the micropylar region. Changes in the uhrastructure of the egg cell and synergids of rice appeared to be closely related to the metabolic processes controlling the embryo sac formation and development.     

A reassessment of the relations in Malaysia between ants (Crematogaster) on trees (Leptospermum and Dacrydium) and epiphytes of the genus Dischidia (Asclepiadaceae) including 'ant-plants'

Three species of epiphytic Dischidia have been investigated in terms of their relationship to ants on trees. Two species, D. parvifolia and D. astephana , are associated with ants and trees in montane areas. A clear association has been found between ants of the genus Crematogaster and the tree Leptospermum flavescens. This relationship is complex and probably both organisms benefit from the association. The ants live in tunnels in the wood of the major branches and the trunk, and the entire tree is occupied by one ant colony. Trees occupied by ants are maintained by the ants substantially clear of epiphytes other than the two species of Dischidia. The potential benefits to the tree and to the ants of this association are noted. The roots of D. astephana and D. parvifolia penetrate into the cavities of these ant nests and presumably gain nutrients from waste in the ant nests. Both Dischidia species are effectively scavenging upon the waste material from the ant-tree association. The leathery dome-shaped leaves of D. astephana are not vital to the development of the scavenging habit as D. parvifolia has lens-shaped leaves, but may offer some advantage to D. astephana by the uptake of nutrients from waste deposited by the ants under the dome-shaped leaves by interception of stem flow and by uptake of gaseous waste. Ants do not nest under these leaves. Seeds of these species of Dischidia are taken by ants into the central woody area of the ant nest where they germinate. Both Leptospermum and Dischidia can be visualized as showing adaptations to a nutient-deficient tropical montane environment. These adaptations are discussed as is the need for reassessment in this genus of the term 'ant-plant', and the need for wider recognition of the 1ant-tree' relationship between Crematogaster and Leptospermum.     

Pandanus subg. Martellidendron (Pandanaceae) part II: revision of sect. Martellidendron Pic. Serm. in Madagascar

This paper provides a taxonomic revision of Pandanus sect. Martellidendron , which so far comprises six species of which only one is known from both staminate and pistillate plants. Research in herbaria and in the field in Madagascar has provided the data on which a revision of the unclear taxonomy of this section can be based. Based on micromorphology, architecture and phytogeography, the number of these dioecious species is reduced. One new species (P. gallinarum Callmander) from the Biosphere reserve of Mananara-North on the east coast is described, and P. karaka Martelli is transferred to this section 30 years after it was assigned to section Dauphinensia. A key to all species of subg. Martellidendron is provided. Finally, the important role of the section for the understanding of the phylogeny of the Pandanaceae is discussed in the context of Indian Ocean biogeography.     

人工合成多样性突变文库研究进展*

突变文库的构建是定向进化研究过程中一个关键步骤,主要利用天然存在的系统或者人工合成的分子技术来产生多样性核酸分子文库,为制备和筛选具有一定特性的蛋白酶、多肽、人工抗体等提供庞大的遗传基因库,也可用于合成生物学中相关基因元件的研究与筛选,为目标生物制品的高效工业化生产提供动力。随着对突变文库构建技术研究的日益深入,各种文库构建策略相继被开发出来,并在生物能源、生物化工、生物医药、生物试剂和食品工业等方面得到了广泛的应用。然而,定向进化中的文库构建策略多有不同,各种突变文库构建技术的核心方法也在不断创新。主要介绍近年来实验室中人工合成多样性文库的前沿技术,并对文库构建技术在自动化和智能化方向的发展进行了展望。     

果实膨大期喷布磷酸二氢钾对三月红荔枝果实贮藏性的影响

在三月红荔枝(Litchi chinensis cv.Sanyuehong)果实膨大期对树冠喷施0.2%磷酸二氢钾(KP)水溶液,以探讨磷酸二氢钾对荔枝果实贮藏性的影响。结果表明:(1) KP处理的果实在贮藏期前17d,失重率及果肉可溶性固形物、酸、VitC、花色素苷等指标的变化趋势与对照基本相似;(2) KP处理的果肉可溶性蛋白质含量变化与对照有明显差异,而果皮的可溶性蛋白质含量在贮藏期前10d变化动态与对照一致,此后呈相反的变化趋势;(3)果皮POD活性显著高于果肉,KP处理和对照的果肉POD活性在贮藏第3d后、果皮POD活性在第17d前分别具有相似变化趋势;(4)果肉中CAT活性在贮藏第3~17d期间都显著或极显著高于果皮,KP处理和对照果肉、果皮CAT活性动态变化均为单峰曲线。     

Homeosis, morphogenetic gradient and the determination of floral identity in the inflorescences ofPhilodendron solimoesense (Araceae)

A comparative developmental study of the inflorescence ofPhilodendron solimoesense was conducted using scanning electron microscopy. The spadix ofP. solimoesense is characterized by unisexual flowers. Staminate flowers are initiated on the upper portion of the spadix while pistillate flowers develop on the lower portion of the spadix. An intermediate zone located between the upper male and lower female portion of the inflorescence consists of sterile male flowers. Within this intermediate zone a row of flowers exhibit polarity with respect to the identity of sexual organs. Stamens are initiated on the flank of the floral meristem facing the upper male zone and carpels are initiated on the portion of the floral meristem facing the lower female zone. The resulting flowers therefore assume a bisexual identity. At the level of the inflorescence, all floral buds are initiated along a series of contact parastichies and the continuity of these parastichies is not disrupted at any level in the male, intermediate, and female zones on the spadix. Results from this study support the presence of a morphogenetic gradient acting at the level of the inflorescence and appears to be independent of the boundaries of floral primordia.     

Ultrastructural aspects of storage lipid mobilization in the tapetum of Lilium hybrida var. enchantment

Stages in the formation and degradation of pollenkitt in the anther of Lilium have been investigated using the electron microscope. This material, which appears to be a complex of lipid and carotenoids, is formed during the autolysis of the tapetal cells by the fusion of lipidic inclusions with globules derived from plastids. Autolysis of the tapetal cells is progressive for it commences with the disintegration of many cytoplasmic components, followed by the breakdown of storage lipids. The plasma membrane maintains its integrity during these events apparently, by proliferation, aiding in the transfer of the products of hydrolysis into the loculus. During the course of lipid breakdown, a striking vacuolar system is formed in the tapetal cytoplasm, presumably containing the products of this hydrolysis. The source of membranes for this system is clearly the lipid globules themselves. The generation of the membrane apparently involves the participation of electronopaque material, possibly enzymic, contained within the lipid globules.     

Study of biocomplexity in an aquatic ecosystem through ascendency

The ascendancy concept aims at quantitatively describing the growth and development of an ecosystem as whole. Growth is an increase in the total system throughflow, while development is taken to be a rise in the average mutual information inherent in the network flow structure. As an ecosystem matures and goes through a series of successional stages, its ascendancy exhibits a propensity to increase. In any ecosystem the equilibrium condition may gradually turn into a chaotic situation for different reasons. In this paper a model is proposed of an aquatic ecosystem comprising of three groups, viz., phytoplankton, zooplankton and fish. Rate parameters are changed according to the change of the size of the organisms. The model is run in different conditions with gradual decrement of the body sizes of zooplankton. Allometric principle of the relationship of body size of zooplankton and two rate parameters (growth rate and half saturation constant) are incorporated in this model. According to allometric principle gradual decrement of body sizes of zooplankton consequently increases the grazing rate and decreases the half-saturation constant of this organisms. The system exhibits different states (equilibrium point--stable limit cycle--doubling and ultimately chaos) by gradual increase of zooplankton grazing rate and decrease of half-saturation constant. This paper tests the high level of ascendancy of the systems at the edge of oscillation before starting of the chaos. This high level of throughflow and mutual information, i.e. Ascendency supports the hypothesis that the system can coordinate the most complex behavior and shows maximum biocomplexity in this situation.