科尔沁沙地沙漠化过程中土壤有机碳和全氮含量变化

通过地面调查,研究了沙漠化对科尔沁沙地农田和草地土壤有机碳和全氮含量的影响.结果表明,随着沙漠化的发展,科尔沁沙地土壤碳、氮含量明显下降.和非沙漠化农田相比,轻度、中度、重度和严重沙漠化农田土壤有机碳和全氮含量分别下降12.3%和15.3%、22.2%和24.7%、39.5%和44.7%、64.4%和63.5%;和非沙漠化草地相比,轻度、中度、重度和严重沙漠化草地土壤有机碳和全氮含量分别下降了56.3%和48.7%、78.4%和74.4%、88.9%和84.6%、91.6%和84.6%.截至2000年,科尔沁沙漠化总面积已经达到50197.5 km2,由于沙漠化而导致的土壤有机碳和全氮损失总量分别为36.39 Mt和7.89 Mt,其中草地分别占91.12%和86.06%,农田分别占8.88%和13.94%.相关分析结果表明,土壤有机碳和全氮的损失主要源于风蚀所引起的土壤粘粉粒的减少.因此,在科尔沁沙地,防治土壤风蚀对于减少农田和草地土壤碳、氮损失极为重要.     

侵蚀泥沙、有机质和全氮富集规律研究

在自然降雨下,研究降雨,坡度,耕作和施肥对侵蚀泥沙,有机质和全N富集率的影响,分析土壤和泥沙颗粒组成,富集与泥沙有机质和全N富集的关系,揭示土壤有机质和全N在泥沙中的富集规律,结果表明,泥沙粘粒的富集导致有机质和全N的富集,泥沙粘粒,有机质和全N富集率分别平均为1．77,2．09和1．61,土壤侵蚀模数与泥沙有机质和全N富集率呈显著的负相关关系,降雨,坡度,施肥和耕作措施对泥沙有机质富集作用的影响通过减少土壤侵蚀模数来实现的,减少土壤侵蚀的措施可增加泥沙有机质和全N的富集。     

保护区广交伙伴开展合作管理的意义与途径

地球人口的迅速增加正在滥用和威胁着本身赖以生存的生态系统和物种多样性的生存,这表现在农田和天然森林面积日益缩小,大量物种陷入受威胁乃至灭绝的境地,大气和水域严重污染,酸雨的产生和危害,石油和化学物质的散落,臭氧层的破裂,城市化失控的扩展,战争和内乱的破坏等。人们对此不能无动于衷,     

中国粮食和农业植物遗传资源状况报告(Ⅱ)

10多年来,中国政府十分重视粮食和农业植物遗传资源的保护和可持续利用,并根据《粮食和农业植物遗传资源全球行动计划》20项优先领域,通过制定和完善相关的法律法规,加强了粮食和农业植物遗传资源的管理;通过培训和科普宣传,提高了公众意识;通过国际合作和协作网建设,实现了信息、人员和植物遗传资源的交流与交换;通过各种国家计划和项目的实施,建立和完善了植物遗传资源保护体系,实现了植物遗传资源的安全保存和可持续利用,为中国乃至世界植物育种和粮食安全发挥了较大作用。     

性类固醇激素及其受体在文昌鱼性腺和神经系统中的分布

首次用雌二醇,睾酮及孕酮受体的多克隆抗体在文昌鱼性腺,脑泡和神经管中进行免疫细胞化学定位研究,结果表明,不同发育时期的卵原细胞和卵母细胞中都存在雌激素,雄激素和孕激素受体,在小生长期,3种受体通常定位在卵原细胞和早期初级卵母细胞的胞质或核膜,在大生长期和成熟期,则定位在胞质和核质,在雄性,3种类固醇激素受体分布在不同发育时期的精原细胞,精母细胞和精子细胞（雌激素受体例外）中,受体阳性物定位在胞质和核,另外,用免疫细胞化学方法和性类固醇激素抗体对文昌鱼不同发育时期的性腺和神经系统进行研究,结果揭示,免疫阳性物存在于不同发育时期的卵巢和精巢中,在卵巢发育是上期,卵原细胞和卵母细胞的胸质和核仁膜对紫二醇,睾酮和孕酮抗体显示强或中等强度免疫阳性反应,在大生长期和成熟期,卵母细胞胞质和核仁膜对睾酮和孕酮抗体的免疫阳性反应明显减弱,而对雌二醇则显著增强,在雄性,随着精原细胞和精母细胞对孕酮抗体发生强的免疫阳性反应,在成熟期则对雌二醇抗体发生免疫阴性反应,精子始终为免疫阴性,本文研究首次发现,文昌鱼脑泡和神经管中存在哺乳动物神经旮体激素样免疫阳性神经细胞及其纤维,免疫阳性物分布在神经细胞胸质,核显阴性反应,这些结果为证明文昌鱼性类固醇激素参与调节性腺发育成熟和生殖内分泌调控轴的功能成熟提供重要的形态学新证据。     

兜兰DEFICIENS(DEF)-和GLOBOSA(GLO)-like基因的克隆及表达分析

以‘同色兜兰’品种为材料,采用RT-PCR和RACE技术获得了DEFICIENS(DEF)-和GLOBOSA(GLO)-like基因的cDNA全长,命名为PcDEF和PcGLO,并用半定量RT-PCR和实时PCR研究了PcDEF和PcGLO在花芽发育过程和不同组织部位的表达特性。结果表明,PcDEF和PcGLO的全长cDNA分别为1 039bp和934bp,分别编码224和210个氨基酸;蛋白比对表明,PcDEF和PcGLO蛋白都具有典型MADS-box蛋白的MADS和K结构域;蛋白同源性分析显示,PcDEF和PcGLO与已登录的其它兰科植物的DEF/AP3和GLO/PI蛋白的相似性分别在75%～96%和87%～98%;系统进化树分析表明,PcDEF和PcGLO分别属于B类MADS-box蛋白家族的AP3和PI亚家族。表达分析显示,PcDEF和PcGLO在花芽发育中均有表达,PcDEF在成熟花、唇瓣和花瓣中的表达量高,在蕊柱、萼片、苞叶和根中次之,在花茎和叶中较低,在子房中几乎不表达;PcGLO在各组织中均有不同丰度的表达。     

锡林河流域草原群落植物多样性和初级生产力沿水热梯度变化的样带研究

 用样带法研究了草原群落植物多样性和初级生产力沿海拔和水分梯度的变化,结果表明;在样带梯度上,物种丰富度、多样性和群落初级生产力与海拔高度、年降水量和土壤有机C及全N含量呈正相关,而与年平均气温和干燥度呈负相关。随着海拔高度的降低,降水量的减少,热量和干燥度的增加,以及土壤有机C和全N含量的降低,草原群落的物种丰富度、多样性和初级生产力逐渐降低。典型相关分析的结果揭示出,土壤有机C含量和干燥度是对草原群落物种丰富度和初级生产力具有更大的影响。同时,草地的利用方式和强度对群落植物多样性和生产力也具有较强的影响。     

锡林河流域草原群落植物多样性和初级生产力沿水热梯度变化的样带研究

 用样带法研究了草原群落植物多样性和初级生产力沿海拔和水分梯度的变化,结果表明;在样带梯度上,物种丰富度、多样性和群落初级生产力与海拔高度、年降水量和土壤有机C及全N含量呈正相关,而与年平均气温和干燥度呈负相关。随着海拔高度的降低,降水量的减少,热量和干燥度的增加,以及土壤有机C和全N含量的降低,草原群落的物种丰富度、多样性和初级生产力逐渐降低。典型相关分析的结果揭示出,土壤有机C含量和干燥度是对草原群落物种丰富度和初级生产力具有更大的影响。同时,草地的利用方式和强度对群落植物多样性和生产力也具有较强的影响。     

贵州蔬菜资源的民族传统文化初步调查

贵州是我国少数民族聚集区,蔬菜资源多样性十分丰富。然而,近些年来随着经济发展,外来文化的渗透,该地区正经历着较大的变迁,少数民族蔬菜资源和传统文化正在逐步消失。为了保护和发扬少数民族的传统文化和蔬菜资源,对该地区的15个县和9个民族进行了系统的蔬菜资源和文化调查,旨在为国家保护和发扬少数民族传统文化,制定蔬菜资源保护政策和科学研究提供基础数据和研究材料。     

国内植物环境胁迫研究应注意的几个基本问题

根据作者多年从事植物逆境研究和教学的经验以及在近几年接触到的国内有关研究工作中发现的问题,为了提高今后研究工作的基础水平和学术期刊稿件的科学水平,特提出几个植物逆境研究中常见到的缺憾和对概念理解上的偏差予以讨论和澄清。问题包括：环境胁迫的定义和定量,植物对环境胁迫的“直接感受”,抗逆性和敏感性,耐逆性和避逆性,适应、驯化和锻炼,环境胁迫的剂量效应关系,伤害和死亡的判定,植物细胞膜的透性和植物自由基清除系统对环境胁迫的反应。     

Variation in infectivity and aggressiveness in space and time in wild host-pathogen systems: causes and consequences

Variation in host resistance and in the ability of pathogens to infect and grow (i.e. pathogenicity) is important as it provides the raw material for antagonistic (co)evolution and therefore underlies risks of disease spread, disease evolution and host shifts. Moreover, the distribution of this variation in space and time may inform us about the mode of coevolutionary selection (arms race vs. fluctuating selection dynamics) and the relative roles of G × G interactions, gene flow, selection and genetic drift in shaping coevolutionary processes. Although variation in host resistance has recently been reviewed, little is known about overall patterns in the frequency and scale of variation in pathogenicity, particularly in natural systems. Using 48 studies from 30 distinct host–pathogen systems, this review demonstrates that variation in pathogenicity is ubiquitous across multiple spatial and temporal scales. Quantitative analysis of a subset of extensively studied plant–pathogen systems shows that the magnitude of within‐population variation in pathogenicity is large relative to among‐population variation and that the distribution of pathogenicity partly mirrors the distribution of host resistance. At least part of the variation in pathogenicity found at a given spatial scale is adaptive, as evidenced by studies that have examined local adaptation at scales ranging from single hosts through metapopulations to entire continents and – to a lesser extent – by comparisons of pathogenicity with neutral genetic variation. Together, these results support coevolutionary selection through fluctuating selection dynamics. We end by outlining several promising directions for future research.     

Electroejaculation in chimpanzees and gorillas and artificial insemination in chimpanzees

Electroejaculation was performed in 3 chimpanzees, 1 pygmy chimpanzee, and 2 gorillas with an instrument that delivers a modified sine wave current with a frequency of 24 Hz. The current stimuli were applied by a rectal probe with longitudinal electrodes. The electrical parameters varied from 6 to 12 V and from 30 to 40 mA for response of erection and lay between 8 and 18 V and between 40 and 145 mA during semen emission. Eleven chimpanzee semen samples showed the following data (x ± SD): total volume 1.9 ± 1.3 ml, volume of the liquid fraction 0.3 ± 0.2 ml, spermatozoa per ejaculate 743 ± 376 × 10⁶, sperm motility 52.7 ± 9.6%, morphologically abnormal spermatozoa 12.2 ± 7.5%. From an adult gorilla, three semen samples were collected, in each case without spermatozoa. The electrostimulation of a 6-year-old gorilla led to an erection, but not to semen emission. Three female chimpanzees were inseminated with fresh or frozen semen, each of them within three different estrous cycles. None of these inseminations led to a pregnancy.     

Advances in purine and pyrimidine metabolism in health and diseases

ABSTRACT

In June, 2015, the Purine and Pyrimidine Society organized the 16th biennial symposium on Purine and Pyrimidine metabolism at the Faculty House of Columbia University, New York City. This exciting meeting focused on these important molecules, new developments in inborn errors of metabolism; therapeutic analogs. In addition, the biochemistry of mammalian and non-mammalian systems were discussed. Due to significant advances in molecular medicine, the boundaries between clinical and basic sciences have merged into exciting translational research, of which a small portion was highlighted in the presymposium.     

MPD and DNA Bending in Crystals and in Solution

Bending of 15 to 24° is observed within crystal structures ofB-DNA duplexes, is strongly sequence-dependent, and exhibits no correlation with the concentration of MPD (2-methyl-2,4-pentanediol) in the crystallizing solution. Two types of bends are observed: facultative bends or flexible hinges at junctions between regions of G·C and A·T base-pairs, and a persistent and almost obligatory bend at the center of the sequence R-G-C-Y. Only A-tracts are characteristically straight and unbent in every crystal structure examined to date. A detailed examination of normal vector plots for individual strands of a double helix provides an explanation, in terms of the stacking properties of guanine and adenine bases. The effect of high MPD concentrations, in both solution and crystal, is to decrease local bending somewhat without removing it altogether. MPD gel retardation experiments provide no basis for choosing among the three models that seek to explain macroscopic curvature of DNA by means of microscopic bending: junction bending, bent A-tracts, or bent general- sequence DNA. Crystallographic data on the straightness of A-tracts, the bendability of non-A sequences, and the identity of inclination angles in A-tract and non-A-tractB-DNA support only the general-sequence bending model. The pre-melting transition observed in A-tract DNA probably represents a relaxation of stiff adenine stacks to a flexible conformation more typical of general-sequence DNA.     

Aminoacylation in Sulfolobus acidocaldarius and in methanogenic and halophilic archaebacteria

Abstract Phenylalanyl-tRNA synthetase (PRS) from the sulphur-metabolizing thermoacidophilic archaebacterium Sulfolobus acidocaldarius has been purified 150-fold using different chromatographic steps. The enzyme has a M _r of 270 000 and exhibits considerable thermostability in a temperature range up to 90°C with optimal activity at 70°C. Conservation of antigenic determinants could not be detected by antibodies against various PRS of all primary kingdoms. As a further means to detect traits of phylogenetic relationship, the cross-species reactivity between PRS and tRNAs of organisms from the three branches of archaebacteria and from all primary kingdoms reveals the group character of all 3 branches of the archaebacterial domain, the sulphur-metabolizing, methanogenic and halophilic archaebacteria.     

Update in research and methods in proteomics and bioinformatics

The 3rd International Conference on Proteomics & Bioinformatics (Proteomics 2013)

Philadelphia, PA, USA, 15–17 July 2013

The Third International Conference on Proteomics & Bioinformatics (Proteomics 2013) was sponsored by the OMICS group and was organized in order to strengthen the future of proteomics science by bringing together professionals, researchers and scholars from leading universities across the globe. The main topics of this conference included the integration of novel platforms in data analysis, the use of a systems biology approach, different novel mass spectrometry platforms and biomarker discovery methods. The conference was divided into proteomic methods and research interests. Among these two categories, interactions between methods in proteomics and bioinformatics, as well as other research methodologies, were discussed. Exceptional topics from the keynote forum, oral presentations and the poster session have been highlighted. The topics range from new techniques for analyzing proteomics data, to new models designed to help better understand genetic variations to the differences in the salivary proteomes of HIV-infected patients.     

Degradation and conversion of somatostatin in normal and diabetic rats in vivo and in vitro

Plasma somatostatin-like immunoreactivity in the portal and jugular veins of streptozotocin diabetic rats was compared with that in normal control rats. In the diabetic group, somatostatin levels in the portal (p less than 0.05) and jugular (p less than 0.01) veins were both elevated compared with those in the control group. Moreover, the degree of elevation was greater in the jugular vein than in the portal vein. To further investigate the role of the liver in the clearance of somatostatin-28 in vivo, 2 micrograms of somatostatin-28 was administered as a bolus into the external jugular vein of intact and functionally hepatectomized rats. The mean half-time of somatostatin-28 was significantly longer in intact diabetic rats than in controls (p less than 0.05). The functional hepatectomy did not cause a significant difference in the half-time in diabetic rats but made it longer in control rats. These results suggest that the longer half-time of somatostatin-28 in diabetic rats in vivo is due to its slower hepatic clearance. The hepatic clearance of somatostatin-28 and somatostatin-14 was further studied in vitro using a recirculating liver perfusion method. The hepatic clearance of 1.2 nM of either somatostatin-28 or somatostatin-14 was significantly lower in diabetic rats than in controls (p less than 0.01). This indicates that elevated plasma somatostatin levels in diabetic rats are caused at least in part by decreased hepatic clearance of somatostatin.(ABSTRACT TRUNCATED AT 250 WORDS)     

Development and comparison of in vivo and in vitro models for endometritis in cows and mares

In order to investigate pathogenic mechanisms of acute endometritis in cows and mares, we established an in vivo model in both species. Based on the results of an in vitro transmigration system, human recombinant interleukin-8 (rhIL-8; 1.25 microg per mare and 5 microg per cow in 50 ml phosphate-buffered saline) was used to attract polymorphonuclear neutrophil granulocytes (PMNs) into the uteri. Peak numbers of uterine neutrophils were attracted after 6h, in both cows and mares. On average, mares responded more sensitively than cows, with 15 times higher numbers of rhIL-8-attracted uterine neutrophils (72+/-8 x 10(7)cells). In contrast to in vitro studies, in vivo migrated neutrophils (uterine neutrophils) of both species displayed a significantly reduced MHC class I expression. Expression of the CD11a molecule was significantly enhanced on equine uterine neutrophils but downregulated on bovine cells. Compared with untreated autologous peripheral neutrophils, both uterine and in vitro migrated neutrophils showed no alteration of phagocytic capacity. The ability to generate reactive oxygen species (ROS) was significantly upregulated in bovine and equine uterine neutrophils. This was also observed after in vitro migration of equine neutrophils, whereas ROS generation by bovine neutrophils was significantly depressed. In summary, the concept of inducing endometritis directly by local application of human interleukin-8 has been reliably successful in cows and mares. The model permits the analysis of PMN migration into the uterus under defined and controlled conditions. The observed differences between cows and mares with respect to phenotypical and functional characteristics of in vivo attracted uterine cells point to species-related features of neutrophil migration. In vitro transmigrated bovine and equine cells partially differ in phenotype and function from uterine neutrophils. Therefore, the in vitro transmigration assay cannot completely represent the in vivo endometritis model described here.     

Trajectories and Constraints in Brain Evolution in Primates and Cetaceans

A negative allometric relationship between body mass (BM) and brain size (BS) can be observed for many vertebrate groups. In the past decades, researchers have proposed several hypotheses to explain this finding, but none is definitive and some are possibly not mutually exclusive. Certain species diverge markedly (positively or negatively) from the mean of the ratio BM/BS expected for a particular taxonomic group. It is possible to define encephalization quotient (EQ) as the ratio between the actual BS and the expected brain size. Several cetacean species show higher EQs compared to all primates, except modern humans. The process that led to big brains in primates and cetaceans produced different trajectories, as shown by the organizational differences observed in every encephalic district (e.g., the cortex). However, these two groups both convergently developed complex cognitive abilities. The comparative study on the trajectories through which the encephalization process has independently evolved in primates and cetaceans allows a critical appraisal of the causes, the time and the mode of quantitative and qualitative development of the brain in our species and in the hominid evolutionary lineage.     

Obestatin and ghrelin in obese and in pregnant women

We identified, through qPCR, receptor mRNA for a number of gut peptides in female human omental fat: the incretins, GIP and GLP-1, the orexigenic peptides PYY-Y1 and -Y2 and ghrelin, and the anorexigenic peptide obestatin. Four cohorts of women were examined: lean controls (BMI<23), obese (BMI>41), obese diabetic and term pregnant women. Human fat expressed receptor mRNAs for all six peptides. Pregnant women expressed roughly three times as much orphan GPR-39 receptor, a proposed obestatin receptor, than other women and less than half as much of the ghrelin receptor (GHSR-1a). An immunoblot probed with a GPR-39 selective antibody yielded a single band corresponding to the correct molecular weight (52 kDa) for the proposed obestatin receptor. Fluorescent immunohistochemistry of human fat employing the same antibody indicated the receptor protein was localized to the adipocyte cell membrane. The concentration of obestatin circulating in blood was measured in the same cohort of women and was significantly lower in obese and obese diabetic women compared to control.