中国主要农产品虚拟要素贸易网络结构特征分析

据虚拟水概念定义虚拟要素,并将其划分为虚拟资源要素和虚拟生态要素两类,选取虚拟资源要素中的耕地要素和虚拟生态要素中的化肥/农药要素为研究对象,定量分析2002—2016年以粮食贸易为载体的虚拟耕地、虚拟化肥/农药要素的贸易量,构建虚拟要素贸易网络,通过复杂网络的研究方法,结果表明:2002—2016年我国主要农产品虚拟耕地、化肥/农药要素的贸易总量呈下降趋势,降幅分别约25.51%、8.01%;虚拟耕地要素网络节点入度较大的为长江中下游、华南、西南地区,出度较大的为黄淮海和东北地区,虚拟化肥/农药要素网络与之相反;地区间节点强度的差异性大,虚拟耕地要素差值最大可达1459.56万hm²,虚拟化肥/农药要素达61.38万t;二者网络节点度和强度的累积分布均符合幂律分布规律,其尾部的"重尾"现象揭示了节点度和强度的高可变性以及网络结构的脆弱性;虚拟耕地要素的输入区网络同配,输出区网络异配,揭示了地区间耕地要素的流动既呈集聚又有分散的态势,虚拟化肥/农药要素网络节点相关性皆为减函数,网络异配,揭示了虚拟化肥/农药要素在八大区域间联通的状况。网络结构特征分析为研究网络抗毁...     

生境梯度影响下的天然红松种群空间格局与种内关联

为理清生境梯度下天然红松种群空间分布规律,以黑龙江省凉水国家级自然保护区内自坡底至坡顶的四种生境(生境Ⅰ,谷地平坡潮湿生境;生境Ⅱ,坡下缓坡潮湿生境;生境Ⅲ,坡上斜坡半湿润生境;生境Ⅳ,坡顶陡坡半干旱生境)类型中建群种红松种群为研究对象。分析不同林层(主林层、亚林层、演替层、更新层)红松种群的数量特征,并基于O-ring函数,在重复采样条件下评价了红松种群空间分布格局。结果表明:(1)下坡位生境(生境Ⅰ、Ⅱ)红松更新层种群数量显著大于上坡位(生境Ⅲ、Ⅳ)(P<0.05),演替层中差异不显著;自坡底至坡顶的生境梯度上,主林层和亚林层中红松株数比例增加,红松种群年龄结构结构由倒J型向J型转变。(2)下坡位原始红松林更新层和演替层中红松种群聚集规模与聚集强度均高于上坡位,坡顶(生境Ⅳ)原始红松林更新层中红松种群聚集规模与聚集强度高于坡上(生境Ⅲ)。(3)四类生境的原始红松林中主林层与更新层中红松种群总体表现为空间独立,在个别尺度上表现出微弱的空间正关联或负关联;在0—5 m尺度上,下坡位红松林原始林内演替层与主林层红松种群表现为空间负关联,而上坡位生境林分对应林层间空间关系则为空间正关...     

中国野生动物调查存在的问题与改进建议

一百余年前,人类就开始了相对系统的野生动物调查。目前已经建立了成熟的方法体系,并制定了相应的调查规范。最近几十年来,我国科研人员进行了大量的野生动物调查。但是,当前我国的野外调查规范还不够细致,调查者在调查时缺乏必要的约束,导致调查数据不规范、不可靠,很多重要信息缺失。突出问题有：样线信息不全,只有起点和终点的经纬度,没有自动记录的详细样线信息（如每秒记录一次的连续点位信息,含经纬度和时间）;动物位点信息缺乏可信度指标（如距观测者的距离）;调查时间不合理;调查地点的空间取样不均衡;记录的标准化不够（如每个观测点的观测时长不确定）等等。对此,我们参考国际通用的调查规范,提出了一些简单易行的调查要点,以便提高野外调查数据的质量。另外,我们提倡野外记录的无纸化,充分利用现有的手机应用软件（APP）和模型工具提高野外记录以及后期数据处理的效率。最后,我们提议建立固定的中国生物多样性监测样线体系,以便消除每年调查时空间取样的不确定性,更好地量化野生动物的时间动态,为野生动物的保护和管理提供依据。     

Quantitative Proteomic Analysis Reveals Important Roles of the Acetylation of ER-Resident Molecular Chaperones for Conidiation in Fusarium oxysporum

Fusarium oxysporum is one of the most abundant and diverse fungal species found in soils and includes nonpathogenic, endophytic, and pathogenic strains affecting a broad range of plant and animal hosts. Conidiation is the major mode of reproduction in many filamentous fungi, but the regulation of this process is largely unknown. Lysine acetylation (Kac) is an evolutionarily conserved and widespread posttranslational modification implicated in regulation of multiple metabolic processes. A total of 62 upregulated and 49 downregulated Kac proteins were identified in sporulating mycelia versus nonsporulating mycelia of F. oxysporum. Diverse cellular proteins, including glycolytic enzymes, ribosomal proteins, and endoplasmic reticulum–resident molecular chaperones, were differentially acetylated in the sporulation process. Altered Kac levels of three endoplasmic reticulum–resident molecular chaperones, PDI^K70, HSP70^K604, and HSP40^K32 were identified that with important roles in F. oxysporum conidiation. Specifically, K70 acetylation (K70ac) was found to be crucial for maintaining stability and activity of protein disulphide isomerase and the K604ac of HSP70 and K32ac of HSP40 suppressed the detoxification ability of these heat shock proteins, resulting in higher levels of protein aggregation. During conidial formation, an increased level of PDI^K70ac and decreased levels of HSP70^K604ac and HSP40^K32ac contributed to the proper processing of unfolded proteins and eliminated protein aggregation, which is beneficial for dramatic cell biological remodeling during conidiation in F. oxysporum.     

Developmental changes in the activities of enzymes related to methyl group metabolism in sheep tissues

The activities of choline oxidase and betaine-homocysteine methyltransferase increased markedly in pre-ruminant lamb liver after birth and subsequently decreased when the lambs reached the ruminant state, while the developmental changes in hepatic 5-methyl-H4folate-homocysteine methyltransferase were negatively correlated with those of betaine-homocysteine methyltransferase. Hepatic phospholipid methyltransferase was elevated almost four-fold by the 10th postnatal day, but declined thereafter. Hepatic glycine methyltransferase in one-day-old lambs increased 55-fold, compared with that of fetuses, and thereafter decreased dramatically with age. Guanidoacetate methyltransferase, glycine methyltransferase and betaine-homocysteine methyltransferase in sheep pancreas increased markedly with age and were many times higher than the hepatic enzymes in adult sheep. Choline oxidase, betaine-homocysteine methyltransferase, cystathionine beta-synthase and glycine methyltransferase in adult sheep liver were much lower than those in rat. These results illustrate the conservative features of methyl group metabolism in postruminant sheep.     

大熊猫精液和包皮菌群组成及潜在致病菌调查

[目的] 大熊猫是我国国家一级保护动物,其种群面临着传染病和栖息地破碎化等持续威胁,其中生殖系统的细菌感染和菌群失衡会影响大熊猫生殖健康,严重者可导致流产,是引起大熊猫繁殖障碍的原因之一。本研究对精液与包皮分泌物样本的菌群组成情况及分离培养潜在致病菌开展研究。[方法] 通过采集13份大熊猫包皮分泌物和12份精液样本,采用16S rRNA扩增子测序技术、细菌培养及PCR鉴定的方法,确定样本中的细菌种类。[结果] 菌群组成分析结果显示,在门水平上,厚壁菌门（Firmicutes）的细菌丰度在大熊猫包皮与精液中均为最高;在属水平上,不同时期的雄性大熊猫包皮的菌群可能会发生改变,棒状杆菌属（Corynebacterium）和Dolosicoccus是Ⅰ期包皮样本中最丰富的微生物菌群,相对丰度分别为15.45%和12.40%;链球菌属（Streptococcus）和埃希氏菌属（Escherichia）是Ⅱ期包皮样本中最丰富的微生物菌群,相对分度分别为37.94%和9.68%;拟杆菌属（Bacteroides）和普雷沃氏菌属（Prevotella）是精液样本中最丰富的微生物菌群,相对丰度分别为14.40%和12.88%。菌群多样性分析结果显示,精液样品高于Ⅰ期包皮样品和Ⅱ期包皮样品,Ⅰ期包皮样品和Ⅱ期包皮样品之间无显著差异。通过细菌分离培养得到肺炎克雷伯菌（Klebsiella pneumonia）在内的多种潜在性致病菌。[结论] 本研究分析了大熊猫精液和不同时期包皮分泌物的菌群组成,其优势菌属存在差异,大熊猫包皮与精液中存在潜在性致病菌,这可能对大熊猫的生殖系统健康带来威胁,其致病性有待进一步研究。     

Man5GlcNAc2哺乳动物甘露糖型糖蛋白的毕赤酵母表达系统构建

蛋白的糖基化对蛋白的活性、高级结构及功能都有重要的影响。酵母表达的糖蛋白不同于哺乳动物表达的杂合型或复杂型糖蛋白,而是高甘露糖型或过度甘露糖化糖蛋白。在前期成功敲除毕赤酵母α-1,6-甘露糖转移酶(Och1p)基因、阻断毕赤酵母过度糖基化,获得毕赤酵母过度糖基化缺陷菌株GJK01 (ura3、och1) 的基础上,通过表达不同物种来源的α-1,2-甘露糖苷酶I (MDSI) 的活性区与酵母自身定位信号的融合蛋白,并通过DSA-FACE (基于DNA测序仪的荧光辅助糖电泳) 分析筛选报告蛋白HSA/GM-CSF (人血清白蛋白与粒细胞-巨噬细胞集落刺激因子融合蛋白) 的糖基结构,发现当编码酿酒酵母α-1,2-甘露糖苷酶 (MnsI) 基因的内质网定位信号与带有完整C-端催化区的拟南芥MDSI基因融合表达时,毕赤酵母工程菌株能够合成Man5GlcNAc2哺乳动物甘露糖型糖蛋白。这为在酵母体内合成类似于哺乳动物杂合型或复杂型糖基化修饰的糖蛋白奠定了基础。     

贵州三都水族Y染色体单倍型频率分析

在92例贵州三都水族个体中,用PCR-RFLP法研究由11个单核苷酸多态位点(SNPs)组成的Y染色体单倍型频率分布,结果显示该人群的Y染色体主要为南方特异的H11和H9单倍型,两者频率高达90.22％。主成分分析结果显示其父系遗传结构与我国黎族、布依族等汉藏语系壮侗语族民族最为接近。通过Y染色体的遗传学观察与历史记载和语言学分类有较好一致性。 Abstract:Non-recombination region of Y-chromosome is a useful marker in tracing evolutionary history of paternal lineage.In the present study,total 92 individuals from Shui ethnic group in Sandu Shui Ethnic Group Autonomous County of Guizhou Province were inspected with 11 SNP sites including M7,M9,M15,M45,M89,M95,M119,M122,M130,M134 and YAP on Y-chromosome.All the subjects were required to be unrelated and without intermarriage with other ethnic groups within three generations.The haplotypes were analyzed by PCR-RFLP method.Four haplotypes H5,H8,H9 and H11 were detected with frequencies of 0.054,0.044,0.315 and 0.587,respectively.Principle component indicated that the paternal lineage of Shui ethnic group is much closer to Li ethnic group of Hainan Province and Bouyei ethnic group of Guizhou Province,which belong to the group of Zhuang-Dong branch of Sino-Tibetan language family.In addition genetic study of Shui coincides with its linguistic distribution.     

急性脑梗死患者血浆同型半胱氨酸水平及其相关因素分析*

目的:探讨急性脑梗死患者血浆同型半胱氨酸水平及相关因素。方法:采用高效液相色谱法检测232例急性脑梗死患者血浆Hcy水平,并对其相关因素进行统计学分析。结果:急性脑梗死组患者血浆Hcy水平明显升高(P<0.05);并与叶酸及维生素B12水平显著相关。不同年龄段急性脑梗死患者血浆Hcy水平具有差异。并与颈动脉粥样硬化斑块相关联。结论:血浆Hcy水平增高是脑梗死的危险因素之一,并与患者年龄、血液中叶酸、维生素B12水平及脑梗死性质相关联。