MMP-9基因多态性与缺血性脑卒中发病及预后的相关性研究

目的:研究基质金属蛋白酶9(MMP-9)基因多态性与缺血性脑卒中(IS)发病及预后的相关性,为IS的防治提供新的理论依据。方法:选取治疗的IS患者100例,根据TOAST分型标准分为大动脉粥样硬化型(LAA)组41例,小动脉阻塞型(SAO)组59例,并选取健康体检者40例作为对照组,采用PCR-RFLP法检测各组MMP-9基因C1562T、R279Q多态性,并对IS患者进行3个月的随访,采用Logistic回归分析C1562T、R279Q多态性与IS患者预后的相关性。结果:LAA组、SAO组MMP-9基因C1562T位点T等位基因、C/T+T/T基因型频数均高于对照组,差异有统计学意义(P0.05),LAA组、SAO组C1562T位点C等位基因、C/C基因型频数及R279Q位点等位基因和基因型频数与对照组比较差异无统计学意义(P0.05);Logistic回归分析显示,MMP-9各型别基因与预后无明显相关性(P0.05)。结论:MMP-9基因C1562T的T等位基因是IS发病的穿易感基因之一,但MMP-9基因多态性与IS患者的预后并无明显相关性。     

囊萼花属─—中国玄参科新记录属及—新种

报道了我国玄参科的一个新记录属──囊萼花属ＣｙｒｔａｎｄｒｏｍｏｅａＺｏｌｌ，该属为印度－马来西亚分布，它经过泰国北部，缅甸与我国发生连系，到达我国云南贡山、屏边、金平。全世界有１１—１２种，我国（云南）首次记录两种，其中一种为新种。     

Heterochromatin and cytogenetic polymorphisms in Cebus apella (Cebidae,Platyrrhini)

Cytogenetic studies have been carried out in 39 specimens of C. apella of different origins. Three different morphologies, one affecting the long arm of chromosome 4 and two affecting pair 17, have been detected. In each case, they can be related by paracentric inversions. Heterochromatin polymorphisms affecting terminal or interstitial C+ regions have also been observed. The length of the terminal heterochromatic region in the long arms of chromosome 11 is variable in C. apella sp., in C. a. paraguayanus and absent in the C. a. nigritus specimens studied. Interstitial C + bands can be observed in the long arms of the biarmed chromosomes 4 and 6, and in the long arms of the acrocentric pairs 12, 13, 17, 18, 19, 20, and 21. Interstitial C + bands in the long arms of chromosomes 4, 12, 17, and 19 are present in all animals studied, although their size is variable, especially in the case of chromosomes 17 and 19. © 1995 Wiley-Liss, Inc.     

Shifting abundances of communities associated with nitrogen cycling in soils promoted by sugarcane harvest systems

Sugarcane cultivation supports Brazil as one of the largest world sugar and ethanol producer. In order to understand the impact of changing sugarcane harvest from manual to mechanized harvest, we studied the effect of machinery traffic on soil and consequently soil compaction upon soil microbial communities involved in nitrogen cycling. The impact of sugarcane harvest was dependent on soil depth and texture. At deeper soil layers, mechanized harvesting increases the abundance of nitrogen fixers and denitrifying communities (specifically nosZ clade I and II) while manual harvesting increases the abundance of ammonia oxidizers (specifically AOA) and increases denitrifying communities (nosZ clade I and II) on top and at intermediate depth. The effect of change on the harvest system is more evident on sandy soil than on clay soil, where soil indicators of compaction (bulk density and penetration resistance) were negatively correlated with soil microorganisms associated with the nitrogen cycle. Our results point to connections between soil compaction and N transformations in sugarcane fields, besides naming biological variables to be used as proxies for alterations in soil structure.     

Tropical ant communities are in long-term equilibrium

Communities change with time. Studying long-term change in community structure permits deeper understanding of community dynamics, and allows us to forecast community responses to perturbations at local (e.g. fire, secondary succession) and global (e.g. desertification, global warming) spatial scales. Monitoring efforts exploring the temporal dynamics of indicator taxa are therefore a critical part of conservation agendas. Here, the temporal dynamics of the Otongachi leaf litter ant community, occurring in a cloud forest in coastal Ecuador, were explored. By sampling this community six times over eleven years, I assessed how the ant fauna caught by Winkler traps (more diverse and cryptic fauna) and caught by pitfall traps (larger, more mobile fauna) changed over time. The Otongachi leaf litter ant community was dynamic. Although species richness in the community remained constant, temporal turnover of species was high: on average, 51% of the ant species in Winkler traps, and 56% of those in pitfall traps, were replaced with other ant species from one year to the other. Shifts in the rank abundance of species in the community were also large across the eleven years and, on average, shifts in the rank abundance of species collected by Winkler traps doubled those occurring in pitfall traps from one census to the other. In spite of these trends, the Otongachi ant fauna showed no (Winkler) or weak (pitfall) evidence of directional change (towards a new community). Thus, this tropical ant community can be divided in two community compartments. The Winkler compartment composed by a more diverse and cryptic ant fauna appears to be resilient and stable in time. The pitfall compartment composed by larger and more mobile ants may be prone to respond to disturbance. This study suggests that 1) species appearing/disappearing from a site may be rather the rule, difficult to separate from responses to ecological stress. 2) Conclusions made in short-term studies, or studies comparing two (e.g. before and after) snapshots of a community, should thus be revisited. Finally, 3) the ant fauna caught by pitfall traps (a rather simple and cheap survey method) is the most likely community compartment to indicate ecological perturbation. This study adds to the growing evidence that using ants as ecological indicators should incorporate long-term temporal dynamics.     

The scale of analysis determines the spatial pattern of woody species diversity in the Mediterranean environment

We examine the spatial pattern of woody species diversity at different scales, in two sites of Mt. Holomontas in northern Greece, which falls within the transitional zone between temperate forests and Mediterranean-type ecosystems. We investigate how diversity is distributed in space and whether the perceived pattern changes with the scale of observation. We use two different metrics of diversity: species richness and species turnover. Our main finding is that the spatial pattern of diversity changes with the scale of observation or analysis. For a given scale, the pattern of species richness (alpha diversity) is negatively correlated with the pattern of species turnover (beta diversity). Species-rich areas have more species in common with their neighbors than species-poor areas. The between-scale disparity of the spatial pattern of diversity may be a general feature of ecological systems. For this to be validated, studies with different groups of species in different biomes and in different biogeographical areas are required; our study contributes to this direction providing evidence that this holds true for woody species in Mediterranean communities. Finally, we discuss how these findings might affect important issues in theoretical and applied ecology, such as identifying the environmental factors driving biodiversity.     

The anatomy of mammalian sweet taste receptors

All sweet‐tasting compounds are detected by a single G‐protein coupled receptor (GPCR), the heterodimer T1R2‐T1R3, for which no experimental structure is available. The sweet taste receptor is a class C GPCR, and the recently published crystallographic structures of metabotropic glutamate receptor (mGluR) 1 and 5 provide a significant step forward for understanding structure‐function relationships within this family. In this article, we recapitulate more than 600 single point site‐directed mutations and available structural data to obtain a critical alignment of the sweet taste receptor sequences with respect to other class C GPCRs. Using this alignment, a homology 3D‐model of the human sweet taste receptor is built and analyzed to dissect out the role of key residues involved in ligand binding and those responsible for receptor activation. Proteins 2017; 85:332–341. © 2016 Wiley Periodicals, Inc.     

闽江河口红树林土壤微生物群落对互花米草入侵的响应

采用磷脂脂肪酸标记法(PLFA)研究外来入侵植物互花米草对闽江河口湿地红树林土壤微生物群落结构的影响,并探讨其主要影响因素。结果表明:从3种不同植被群落土壤(红树林群落MC、红树林-互花米草混生群落MS、互花米草群落SC)共检测到22种PLFA生物标记,MS土壤微生物PLFA生物标记总量明显高于其他植被群落,3种植被群落土壤理化性质和酶活性的变化趋势为:MCMSSC,表明互花米草入侵后土壤微生物量增加,而理化性质和酶活性均有明显下降,红树林湿地土壤质量发生了明显退化。3种植被群落土壤中含量最高的PLFA生物标记是16:0,16:1w7c,9Me15:0w,18:1w12c。土壤中特征微生物相对生物量存在明显差异,细菌分布量最大,其次是真菌和放线菌,原生动物分布量最小。群落多样性指数呈相似规律,MS土壤微生物类群多样性指数均小于MC,表明互花米草入侵后土壤微生物群落多样性指数均有下降。通过主成分分析,基本能区分出3种不同植被群落微生物群落的特征。土壤理化性质、酶活性间存在相关性,有机碳、全氮、蔗糖酶、过氧化氢酶与革兰氏阴性菌、放线菌呈显著或极显著正相关。研究结果表明互花米草入侵在一定程度上具有影响红树林群落土壤营养代谢循环的潜力,特别是关于碳、氮、磷等的循环及酶活性,改变部分有利于自身生长的土壤环境相关的微生物类群含量,竞争有利环境,迅速扩张实现入侵。     

萘对川西亚高山森林土壤微生物量、丰度和磷脂脂肪酸的影响

萘作为土壤动物化学抑制剂已在土壤动物生态功能的研究中广泛使用,但其非目标效应使其应用仍存在很大的不确定性。为了解在亚高山森林土壤应用萘抑制土壤动物群落的非目标效应,以川西亚高山森林土壤为研究对象,采用微缩实验研究了土壤微生物生物量、丰度和磷脂脂肪酸对萘胁迫的短期响应。结果表明,萘处理和对照的土壤微生物生物量碳(MBC)、真菌丰度以及细菌、真菌、革兰氏阳性菌(G~+)和革兰氏阴性菌(G~-)PLFAs含量在整个培养期间表现为降低的变化趋势,二者的土壤微生物生物量碳和G~+PLFAs含量以培养52d最低,细菌、真菌和G~-PLFAs含量以培养的45d最低。萘处理和对照的微生物生物量氮(MBN)含量表现出先升高后降低的动态,微生物生物量碳氮比(MBC/MBN)则表现为相反趋势。对照的真菌/细菌PLFAs比值呈现先升高后降低的动态,以培养的17d最高,但萘处理的真菌/细菌PLFAs比值无明显变化规律;萘处理的G~+/G~-PLFAs比值表现为降低的变化趋势,对照的G~+/G~-PLFAs比值表现为先降低后升高的趋势。萘处理仅显著影响了G~+/G~-PLFAs比值,但萘处理和采样时间的交互作用显著影响MBC/MBN、细菌丰度、真菌/细菌丰度比以及细菌、真菌的PLFAs含量、真菌/细菌PLFAs比值、G~+/G~-PLFAs比值。萘作为土壤动物抑制剂对川西亚高山森林土壤微生物群落的非目标效应具有时间变异性。