基于MAXENT模型的秦岭山系黑熊潜在生境评价

明确物种生境空间分布格局及其与环境因子的关系,对制定合理有效的保护对策十分重要.本文以黑熊(Ursus thibetanus)为研究对象,以其重要柄息地秦岭山系为研究区域,选取68个黑熊分布点数据和34个环境因子,应用MAXENT模型分析其生境空间分布及主要影响因子,以最大化Kappa值的生境适宜性指数为阈值划分适宜生境,结合已建自然保护区进行保护空缺分析,并通过构建阻力面和最小成本路径分析,开展黑熊生境廊道规划.结果表明:人类干扰和土地利用类型是影响黑熊生境选择的主要生态因子,居民点密度、到荒草地距离、到耕地距离3个因子对黑熊生境选择有重要影响,其综合贡献值分别为21.4%、17.5%和15.9%,到阔叶林距离、到水体距离等因子次之.黑熊的适宜生境主要集中分布在秦岭山系主脊的中西部地区,占整个秦岭山系面积的19.23%.空缺分析表明:已建自然保护区群覆盖了23.49%的适宜生境,但尚有8,480 km2处于保护区之外.为更有效保护秦岭黑熊及其生境,建议建设12条生境廊道,同时结合其他物种进行系统保护规划.     

植被冠层尺度生理生态模型的研究进展

随着人们对植物生命活动各个过程研究的不断深入,以植物生理过程、物理过程为基础的各种生理生态学模型逐渐发展起来,而植被冠层尺度生理生态学过程模型已成为生态系统模型的核心之一。目前植被冠层尺度的大叶模型、多层模型、二叶模型以其成熟的理论基础及对植被冠层的光合作用、蒸腾作用较为成功的模拟,得到了广泛的应用。3个模型都以光合作用-气孔导度-蒸腾作用耦合模型为基础,但又具有各自的特点。本文对3种模型的结构及特点进行了总结,并对其进行了比较,简要介绍了目前植被冠层尺度生理生态学模型的应用及存在的问题和发展状况。     

BP人工神经网络模拟杨树林冠蒸腾

利用2008和2010年的气温、饱和差、总辐射和叶面积指数作为模型输入,液流法观测的蒸腾速率作为模型输出,建立了用于杨树林冠蒸腾模拟的BP人工神经网络模型,利用2009年的观测数据对模型的模拟能力进行了检验,并应用连接权值计算得到的输入变量对输出变量的相对贡献进行了敏感性分析。结果表明:建立的BP人工神经网络蒸腾模型可以很好的模拟林冠蒸腾大小和季节变化,模拟的绝对误差和绝对相对误差的平均值分别为0.11 mm/d和9.5%,纳什效率系数为0.83;输入变量对蒸腾的相对贡献以及蒸腾与输入变量之间的相关性大小顺序相同,均为总辐射叶面积指数饱和差气温。     

肠道菌群紊乱症的生态防治疗法初报

我们使用生态防治疗法,治疗了20例因长期不当使用广谱抗生素而引起疡道菌群紊乱症的病人,其主要症状是腹泻和重复感染,我们根据肠道菌群的变化,灵活地应用生态制剂,20例病人全部治愈。     

健康人皮肤正常菌群的研究

本研究对我国健康人皮肤正常菌群进行了探讨,发现在健康人前额皮肤上表皮葡萄球菌数为1.6×10~2～1.7×10~7/厘米~2,疮疤丙酸杆菌数为5.3×10~2～4.1×10~7/厘米~2,棒状杆菌数为1.31×10~2～4.1×10~4/厘米~2,真菌为0.17×10~2～6.1×10~3/厘米~2。在全皮标本中疮疱丙酸杆菌数为1.12×10~2～1.7×10~5/厘米~2,表皮葡萄球菌为1.36×10~2～3.9×10~2/厘米~2。表皮标本中,随年龄增加,表皮葡萄球菌有所减少,而金黄色葡萄球菌则增多。男女性皮肤正常菌群的比较中,表皮葡萄球菌、棒状杆菌、疮疱丙酸杆菌男性高于女性,而金黄色葡萄球菌、真菌却女性多于男性,但差异都不显著。全皮标本与表皮标本的比较中,表皮标本中表皮葡萄球菌、疮疱丙酸杆菌、金黄色葡萄球菌、棒状杆菌和真菌数都多于全皮标本,只是上述的后三种菌群的差异显著。     

Limiting effects of RIP140 in estrogen signaling: potential mediation of anti-estrogenic effects of retinoic acid

The receptor interacting protein 140 (RIP140) belongs to a unique subclass of nuclear receptor coregulators with the ability to bind and repress the action of a number of agonist-bound hormone receptors. We have previously demonstrated that all-trans-retinoic acid (RA) induction of RIP140 constitutes a rate-limiting step in the regulation of retinoid receptor signaling. Here we demonstrate that RIP140 is also a limiting regulator of estrogen receptor signaling. Overexpression of RIP140 dose dependently inhibits estrogen-dependent reporter activity in human breast cancer cells. Furthermore, small interfering RNA to RIP140 enhances estrogen-dependent signaling. Our previous studies indicate that RIP140 is a direct target of RA. We report here that RA can abrogate estrogen-mediated cell cycle re-entry. In addition, RA treatment of estrogen-dependent breast cancer cells opposes estrogen receptor-dependent reporter activity, implying that a proportion of RA effects are anti-estrogenic. We provide evidence for a role for RIP140 in mediating anti-estrogenic effects of RA. RIP140 small interfering RNA blocks RA-mediated repression of estrogen receptor activity and provides a growth advantage to estrogen-dependent cells. Together these data implicate a regulatory role for RIP140 in mediating anti-estrogenic effects of RA in estrogen-dependent breast cancer cells and suggest that acute regulation of coregulator expression may be a general mechanism to integrate diverse hormone signals.     

Efficient targeting of conserved cryptic epitopes of infectious agents by single domain antibodies. African trypanosomes as paradigm

Antigen variation is a successful defense system adopted by several infectious agents to evade the host immune response. The principle of this defense strategy in the African trypanosome paradigm involves a dense packing of variant surface glycoproteins (VSG) exposing only highly variable and immuno-dominant epitopes to the immune system, whereas conserved epitopes become inaccessible for large molecules. Reducing the size of binders that target the conserved, less-immunogenic, cryptic VSG epitopes forms an obvious solution to combat these parasites. This goal was achieved by introducing dromedary Heavy-chain antibodies. We found that only these unique antibodies recognize epitopes common to multiple VSG classes. After phage display of their antigen-binding repertoire, we isolated a single domain antibody fragment with high specificity for the conserved Asn-linked carbohydrate of VSG. In sharp contrast to labeled concanavalin-A that stains only the flagellar pocket where carbohydrates are accessible because of less dense VSG packing, the single domain binder stains the entire surface of viable parasites, irrespective of the VSG type expressed. This corroborates the idea that small antibody fragments, but not larger lectins or conventional antibody fragments, are able to penetrate the dense VSG coat to target their epitope. The diagnostic potential of this fluorescently labeled binder was proven by the direct, selective, and sensitive detection of parasites in blood smears. The employment of this binder as a molecular recognition unit in immuno-toxins designed for trypanosomosis therapy becomes feasible as well. This was illustrated by the specific trypanolysis induced by an antibody::beta-lactamase fusion activating a prodrug.     

用~1H NMR和FT－IR研究hF－GRP及其类似物TF14与DMPC脂质体的相互作用

用１ＨＮＭＲ和ＦＴ－ＩＲ技术研究了肽激素ｈＦ－ＧＲＰ及其类似物ＴＦ１４与ＤＭＰＣ脂质体的相互作用及其构象变化,１Ｈ－ＮＭＲ实验结果提示这两个肽与ＤＭＰＣ之间存在静电相互作用,这使其可从水相结合到脂相中。ＦＴ－ＩＲ实验结果显示它们的构象从水相到脂相确实发生了某些调整变化,ｈＦ－ＧＲＰ趋于更加固定和弯曲,ＴＦ１４趋于更加伸展。以上工作为进一步从事ｈＦ－ＧＲＰ和ＴＦ１４受体结合的研究奠定了基础。     

肠通透性改变的研究初报

本文用气相色谱测定烧伤猪和羊的ＭＳＯＦ动物模型尿内乳果糖和甘露醇分泌比率（Ｌ／Ｍ）。烧伤猪治疗组７２小时Ｌ／Ｍ分泌比率为０．０２４±０．００７,而对照组为０．０２６±０．００３,伤前Ｌ／Ｍ分泌比率为０．００７±０．００５,与伤前比较,无显著性差异。这说明Ｌ／Ｍ分泌比率升高与烧伤前期治疗及伤后天数无关。而在羊的ＭＳＯＦ的动物模型内Ｍ组中,输入内毒素４小时及伤后３天的Ｌ／Ｍ分泌比率为０．６２±０．２、１．７０±０．６０,对照组为０．２８±０．２５、０．２０±０．１０,伤前为０．０２９±０．０２,Ｌ／Ｍ分泌比率升高显著（Ｐ＜０．０５）,提示内毒素血症可能与肠通透性改变之间具有密切联系。     

烧伤猪肠道膜菌群的微生态失调研究

本研究定量地分析了烧伤猪山莨菪碱治疗组和对照组的肠道粘膜及内容物中５类菌群,对内脏标本进行了细菌培养。其中治疗组猪的空肠膜菌群,肠杆菌的活菌计数（Ｌｇ１０￣（ｘ±ｓ））为５．６７±０．８５,肠球菌为２．６０±０．２３,双歧杆菌为５．２７±０．７１,类杆菌为３．９１±０．８３,乳杆菌为２．２０±０．１３;回肠膜菌群中５类菌活菌计数分别为５．８３±０．４２,２．５８±０．２１,５．６３±１．０２,４．０３±１．１１,２．５８±０．２１,５．６３±１．０２,４．０３±１．１１,２．５８±０．２;盲肠菌膜群依次为６．６２±１．２７,２．７１±０．４５,６．２３±１．５２,６．６７±１．２９,３．４３±１．２９;而盲肠内容物的５类菌数分别为８．０５±０．３１,３．５７±０．６５,７．７８±０．６２,６．９１±０．９６,５．４４±１．９８。内脏组织发生了细菌移位．对照组与治疗组都出现了微生态失调。结果显示山莨菪碱不能调整菌群失调症。