基因芯片技术在微生物学研究中的应用

近年来,基因芯片技术的诞生使得在一个实验中就可以同时对成千上万个基因进行转录水平的表达和DNA同源性分析成为可能。该项技术已被应用于揭示许多微生物体的转录表达和基因组的差异,随着越来越多的微生物基因组全序列测定的完成,基因芯片正逐渐成为许多微生物学研究领域中的一项常规技术。归纳了该技术在微生物生理,致病性,流行病学,生态,进化,代谢工程及发酵优化等研究中的应用。     

The physiologic complexity of beat-to-beat blood pressure is associated with age-related alterations in blood pressure regulation

The fluctuations in resting-state beat-to-beat blood pressure (BP) are physiologically complex, and the degree of such BP complexity is believed to reflect the multiscale regulation of this critical physiologic process. Hypertension (HTN), one common age-related condition, is associated with altered BP regulation and diminished system responsiveness to perturbations such as orthostatic change. We thus aimed to characterize the impact of HTN on resting-state BP complexity, as well as the relationship between BP complexity and both adaptive capacity and underlying vascular characteristics. We recruited 392 participants (age: 60–91 years), including 144 that were normotensive and 248 with HTN (140 controlled- and 108 uncontrolled-HTN). Participants completed a 10-min continuous finger BP recording during supine rest, then underwent measures of lying-to-standing BP change, arterial stiffness (i.e., brachial-ankle pulse wave velocity), and endothelial function (i.e., flow-mediated vasodilation). The complexity of supine beat-to-beat systolic (SBP) and diastolic (DBP) BP was quantified using multiscale entropy. Thirty participants with HTN (16 controlled-HTN and 14 uncontrolled-HTN) exhibited orthostatic hypotension. SBP and DBP complexity was greatest in normotensive participants, lower in those with controlled-HTN, and lowest in those in uncontrolled-HTN (p < 0.0005). Lower SBP and DBP complexity correlated with greater lying-to-standing decrease in SBP and DBP level (β = −0.33 to −0.19, p < 0.01), greater arterial stiffness (β = −0.35 to −0.18, p < 0.01), and worse endothelial function (β = 0.17–0.22, p < 0.01), both across all participants and within the control- and uncontrolled-HTN groups. These results suggest that in older adults, BP complexity may capture the integrity of multiple interacting physiologic mechanisms that regulate BP and are important to cardiovascular health.     

Advances in the study of CDC42 in the female reproductive system

CDC42 is a member of the Rho‐GTPase family and is involved in a variety of cellular functions including regulation of cell cycle progression, constitution of the actin backbone and membrane transport. In particular, CDC42 plays a key role in the establishment of polarity in female vertebrate oocytes, and essential to this major regulatory role is its local occupation of specific regions of the cell to ensure that the contractile ring is assembled at the right time and place to ensure proper gametogenesis. The multifactor controlled ‘inactivation‐activation’ process of CDC42 also allows it to play an important role in the multilevel signalling network, and the synergistic regulation of multiple genes ensures maximum precision during gametogenesis. The purpose of this paper is to review the role of CDC42 in the control of gametogenesis and to explore its related mechanisms, with the aim of further understanding the great research potential of CDC42 in female vertebrate germ cells and its future clinical translation.     

Cloning and characterization of a NAD+-dependent glycerol-3-phosphate dehydrogenase gene from Candida glycerinogenes, an industrial glycerol producer

The osmotolerant yeast Candida glycerinogenes produces glycerol as a major metabolite on an industrial scale, but the underlying molecular mechanisms are poorly understood. We cloned and characterized a 4900-bp genomic fragment containing the CgGPD gene encoding a glycerol-3-phosphate dehydrogenase homologous to GPD genes in other yeasts using degenerate primers in conjunction with inverse PCR. Sequence analysis revealed a 1167-bp open reading frame encoding a putative peptide of 388 deduced amino acids with a molecular mass of 42 695 Da. The CgGPD gene consisted of an N-terminal NAD⁺-binding domain and a central catalytic domain, whereas seven stress response elements were found in the upstream region. Functional analysis revealed that Saccharomyces cerevisiae gpd1 Δ and gpd1 Δ/ gpd2 Δ osmosensitive mutants transformed with CgGPD were restored to the wild-type phenotype when cultured in high osmolarity media, suggesting that it is a functional GPD protein. Transformants also accumulated glycerol intracellularly and GPD-specific activity increased significantly when stressed with NaCl, whereas the S. cerevisiae mutants transformed with the empty plasmid showed only slight increases. The full-length CgGPD gene sequence including upstream and downstream regions has been deposited in GenBank under accession no. EU186536 .     

碱地肤的生态、生理适应性及其群落特征

本文采用野外调查分析和室内实验相结合的方法,研究了碱地肤（Ｋｏｃｈｉａｓｉｅｖｅｒｓｉａｎａ）的生态、生理适应性及其组成的群落,结果表明：（１）碱地肤有一定的耐碱能力,生态幅度较窄。它与生境的关系及种群的数量调节是其生态适应性的体现。（２）碱地肤对盐碱生境的适应是由于体内具有某些生理调节功能,主要的如呼吸强度随着盐浓度升高而下降,同时ＡＴＰ含量减少;细胞膜透性随着盐浓度增高而加大,脯氨酸的积累增多。（３）碱地肤与不同植物组成多个群落,其生态优势度体现了群落种类组成的变化,反映土壤碱化程度的差异,构成羊草草地退化的一个演替系列。     

变灰青霉线粒体基因组特征及系统发育分析

本研究对一株分离自细虫草上的变灰青霉SFY00C3菌株线粒体基因组进行测定,分析其组成特征,并探究其与青霉属真菌的系统发育关系。结果表明,SFY00C3的线粒体基因组是一条长度为28 301 bp的环状DNA分子,共编码42个基因(15个蛋白编码基因、2个rRNA基因和25个tRNA基因),其碱基组成有显著的A-T偏好性,25个tRNA基因均可形成典型三叶草结构,并存在32处G-U错配。通过青霉属物种间共线性分析发现其线粒体基因组发生了基因重排;共有的14个蛋白编码基因的Ka/Ks值均小于1,表明受到了纯化选择压力的影响;系统发育分析表明：SFY00C3在青霉属中是一个独立的分支,应该是6种青霉祖先的姊妹。本研究丰富了变灰青霉的线粒体基因组序列信息,为青霉属的系统发育、资源保护及遗传多样性研究提供基础数据。     

新疆艾比湖流域土壤有机质的空间分布特征及其影响因素

根据新疆艾比湖流域土壤有机质(SOM)数据,分析了土壤质地、植被群落类型和土壤剖面深度3个因素对SOM含量的影响,进一步研究了流域内有机质在不同土壤深度的空间分布特征及其沿土壤剖面深度垂直分布的空间异质性。结果表明:植被群落类型显著影响SOM含量,而土壤质地和深度对有机质总体分布水平影响不显著;随土壤深度变化有机质分布呈现不同的空间变异特征,流域内0—80 cm土壤有机质高含量区域与低含量区域斑块化分布呈现孔穴特征,但在80—120 cm土壤有机质含量变化较为连续,呈现流域东、西两端高而中间低的分布特征;有机质沿土壤深度垂直分布模式在流域内表现出分异特征,流域中部SOM随土壤深度增加而降低,SOM含量从0—20 cm浅层土壤的2.85 g/kg降至100—120 cm深层土壤的1.51 g/kg;但在流域东部和西部SOM随土壤深度增加呈升高趋势,流域西部SOM含量从0—20 cm土壤的1.80 g/kg大幅增加至100—120cm土壤的6.61 g/kg,流域东部SOM含量则从0—20 cm土壤的1.04 g/kg逐步增至100—120 cm土壤的2.86g/kg。艾比湖流域有机质在浅层和深层土壤不同的空间分布特征与干旱区绿洲生态景观斑块化分异特征和植被根际沉积特点密切相关,流域内土壤剖面成土演化的空间异质性对有机质沿土壤深度垂直分布的空间变异性有显著制约。     

藏东南亚高山冷杉林林隙特征与干扰状况研究

从林隙的大小结构、干扰频率、形成方式及林隙内形成木的数量特征等几个方面,对藏东南色季拉山亚高冷杉林的典型群落类型－－藓类冷杉林的林隙干扰关况进行了分析。结果表明,在冷杉林中,扩展林隙（EG）和冠空隙（CG）的面积分别占林分总面积的41．73％和14．71％;平均每年有0．82％的林分面积转化为扩展林隙,0．29％的林分面积转化为冠空隙;每年1hm^2面积上约有0．31个林隙形成;林隙的干扰周期为345年,在调查的16个林隙中,共有形成木（GM）78株,平均每个林隙中有4．88株,形成林隙最主要的方式是形成木的折倒,其次为根和枯立,主要外力作用是风,当主林层林木直径达到40－60cm、高度15－20m时,形成林隙的可能性最大;同一林隙常常受到形成木多种死亡方式的影响,且形成时期各不相同,藏东南亚高山杉林林由不同年代的多次干扰而形成。     

产甘油假丝酵母甘油代谢关键酶的研究

本文对产甘油假丝酵母的甘油代谢关键酶进行了研究,发现产甘油假丝酵母同化甘油能力极弱,少量葡萄糖明显改善其同化甘油的能力;线粒体3磷酸甘油脱氢酶受3磷酸甘油的强烈诱导,受葡萄糖代谢的阻遏。在甘油发酵过程中,产甘油假丝酵母胞浆3磷酸甘油脱氢酶酶活处于较高水平并在36h和60h时出现两次酶活高峰,其中第一次酶活峰值水平决定产甘油假丝酵母的甘油合成和积累水平,成为甘油高速积累期(18～48h)甘油合成的关键性的限速酶。在甘油发酵18～48h内,3磷酸甘油酯酶的酶活处于高水平,并在36h时出现酶活峰值;处于缓慢甘油积累阶段的48～72h间,3磷酸甘油酯酶已处于低水平表达,此时,3磷酸甘油酯酶则成为甘油合成的限速酶。产甘油假丝酵母稳定并高表达其胞浆3磷酸甘油脱氢酶基因并且其所表达的3磷酸甘油酯酶酶活远高于胞浆3磷酸甘油脱氢酶这一特征是其高产甘油根本所在。