卧龙自然保护区大熊猫空间利用格局动态变化特征

野生动物在长期的栖息地选择过程中,能判断其生境质量,而趋向于选择既能降低能量消耗,又能获得营养价值和能量净收益较高的有利生境。以往的研究多是从统计学方法或宏观尺度对大熊猫生境进行评价,很少考虑到野生动物自身生物学特性及生境选择过程中的空间利用特征。本研究结合家域模型与景观格局分析技术定量分析大熊猫实际空间利用格局的动态变化特征及其破碎化程度,进而反映不同时期大熊猫生境选择模式及栖息地生境适宜性的动态变化。结果表明：卧龙自然保护区大熊猫在对栖息地的实际利用过程中向更适宜的区域集中,使得高适宜等级区域面积有所增大;而边缘生境区域更容易受到自然灾害和人为因素的干扰,破碎化加剧,需要在保护工作中引起足够的重视。从大熊猫行为模式特征出发,在不同时空尺度上,评估大熊猫对生境选择的空间格局变化特征,丰富了野生动物栖息地适宜性评价的时空尺度选择,为更准确地制定保护区管理政策提供了有效的工具。     

亚洲象生境长时序变化及其对人象冲突的影响——基于融合MaxEnt与HSI模型的生境适宜性评价方法

生境变化直接关系到物种种群维持与人类安全,揭示其长期变化规律及其对人类的影响,可为物种保护与生境恢复提供科学支撑。但因受物种活动点数据获取与位置精度的局限,鲜见濒危、危险物种的长时序生境变化研究。以人象冲突频发的西双版纳勐海—普洱澜沧地区亚洲象种群(勐海—澜沧象群)活动区为例,提出融合MaxEnt与HSI模型的亚洲象长时序生境适宜性评价方法,即基于荟萃分析筛选出的15个亚洲象生境评价因子,结合近期有限的物种活动点监测数据,利用MaxEnt得到生境评价因子的贡献率,再运用HSI模型计算生境适宜性指数;利用该方法制作出研究区1988—2020年逐年时序的亚洲象生境适宜性图,以分析亚洲象生境的时空变化,将其与亚洲象肇事数据结合,进而分析人象冲突与生境变化的关联。结果表明：(1)基于物种生境偏好不变的前提,融合MaxEnt模型与HSI模型的生境适宜性评价方法可应用于物种的长时序生境评价,且基于亚洲象活动点数据从动物对生境利用的生态学视角定量获取亚洲象对各生境评价因子的偏好程度,使生境评价结果具有良好的生态可解释性;(2)目前亚洲象适宜生境面积占研究区面积三分之一(4039.76 km^...     

四川省汶川县土地利用变化对森林野生动物生境的影响

基于野外调查和地理信患系统技术,对四川省汶川县1974-2000年的土地利用变化进行了分析,并结合生境适宜性模型对野生动物生境适宜性进行了评价,分析了适宜生境变化的原因.结果表明:研究区1974-2000年土地利用变化明显,森林面积下降,而草地、灌木林地和农田增加;野生动物适宜生境减少,核心区面积减少且距离加大,不利于野生动物的保护.造成这一变化的主要原因是人口的增加和地区经济发展.因此,在经济发展的同时,应该加强野生动物的保护.     

物种分布模型在海洋潜在生境预测的应用研究进展

海洋生物的栖息分布与环境要素的关联性一直是海洋生态学研究的热点之一.近年来,物种分布模型被广泛应用于预测海洋物种分布、潜在适宜性生境评价等研究,为保护海洋生物多样性、防治外来物种入侵及制定渔业管理措施等提供了一条有效途径.物种分布模型主要包括生境适宜性指数模型、机理模型和统计模型.本文对物种分布模型的理论基础进行了归纳和总结,回顾了物种分布模型在预测海洋物种潜在地理分布研究中的开发与应用,重点介绍了不同类型统计模型在海洋物种潜在分布预测中的研究实例.比较各种选取变量和模型验证方法,认为赤池信息准则对于选取模型变量具有优势,Kappa系数和受试者操作特征曲线下面积在验证模型精度中应用最广泛.阐述了物种分布模型存在的问题及未来发展趋势,随着海洋生物生理机制研究的进一步深入,机理模型将是今后物种分布模型发展的重点.     

不同森林管理预案对松鼠生境的影响

应用空间直观的森林景观干扰演替模型（LANDIS）模拟了2000—2200年间小兴安岭友好林区4种森林管理预案（无采伐、皆伐、择伐Ⅰ和择伐Ⅱ）下的森林景观变化,并结合景观尺度的生境适宜度指数（HSI）模型评估了不同管理预案对研究区松鼠生境的影响.结果表明：研究期间,无采伐下松鼠适宜生境面积的增幅最快,而勉强适宜生境的降幅最快;皆伐下,松鼠适宜生境面积的增幅最慢,而勉强适宜生境的后期降幅最小;择伐Ⅰ下松鼠适宜生境面积的增幅高于择伐Ⅱ,而其勉强适宜生境面积的降幅低于择伐Ⅱ.整体而言,松鼠生境最优化的管理方案依次为无采伐、择伐Ⅰ、择伐Ⅱ和皆伐.     

四川省汶川县土地利用变化对森林野生动物生境的影响四川省汶川县土地利用变化对森林野生动物生境的影响

基于野外调查和地理信息系统技术,对四川省汶川县1974—2000年的土地利用变化进行了分析,并结合生境适宜性模型对野生动物生境适宜性进行了评价,分析了适宜生境变化的原因。结果表明：研究区1974—2000年土地利用变化明显,森林面积下降,而草地、灌木林地和农田增加;野生动物适宜生境减少,核心区面积减少且距离加大,不利于野生动物的保护。造成这一变化的主要原因是人口的增加和地区经济发展。因此,在经济发展的同时,应该加强野生动物的保护。     

基于多尺度的丹顶鹤生境适宜性评价——以黄河三角洲自然保护区为例

尺度是生态学中的一个核心问题,基于多尺度更能抓住物种一环境之间关系.生境适宜性模型可以定量并多尺度研究物种一环境关系,被广泛应用于野生动物生境适宜性评价中.本文以丹顶鹤(Grus japonensis)为研究对象,以其迁徙和越冬的重要地区--黄河三角洲自然保护区为研究区域,应用二项逻辑斯谛回归模型,并结合地理信息系统和遥感技术,在10-1,500 ha之间,通过变换空间尺度大小构建了10个空间尺度下丹顶鹤生境适宜性模型.通过检测尺度对模型构建的影响,选择最佳模型开展丹顶鹤生境适宜性分析和评价.尺度影响分析结果表明:环境因子的拟合能力和模型的预测精度均存在尺度效应,空间尺度为50 ha时的单尺度模型为最佳单尺度模型,多尺度模型优于所有单尺度模型.模型分析结果表明:丹顶鹤适宜生境占保护区总面积的25%以上,且大部分适宜生境分布在自然保护区南部,自然保护区北部由于缺乏淡水来源,适宜生境较少.为有效保护丹项鹤生境,建议加强保护区湿地生境监测、评价和规划.以及对人为干扰活动进行监督和管理.     

分析地理信息系统在野生动物生境选择研究中的运用

地理信息系统(GIS)技术是一种十分先进的技术,并且已经应用到我国的许多行业之中。而近年来,在野生动物的生境选择研究中,也将该技术引入到了其中,并且为野生动物生境选择的研究做出了很大的贡献。因此,对于地理信息系统在野生动物生境选择中运用的研究具有十分重要的意义。本文主要阐述了GIS的主要功能和数据管理方式,并对地理信息系统在野生动物生境选择研究中的应用进行了一定的探索,旨在为提高地理信息系统在野生动物生境选择中的应用而提供一些有价值的参考意见。     

基于生境适宜性指数模型的俚岛海黍子生境层级分布

为了深入了解海黍子生境,利用模型对山东俚岛海黍子生境进行适宜性分析,分别选取温度、盐度、水深、浊度、底质、无机氮浓度、磷酸盐浓度和距海藻床距离8种环境因子,通过层次分析法赋值因子权重,结合空间分析方法建立了海黍子HSI模型。利用该模型对山东俚岛近岸海域2018年春、秋两季的环境因子调查结果进行了海黍子生境分析。结果表明: 研究区域内的海黍子海藻床区域主要由极佳生境和适宜生境组成,春季和秋季的分布面积分别占14.2%和18.6%。海黍子生境层级分布随季节而变化,且不同季节的生境层级具有一定的空间重合性。温度和磷酸盐浓度的适宜性变化具有明显的季节性差异,是导致俚岛海黍子HSI季节变化的主要原因。海黍子HSI模型不仅可用于检测海黍子海藻床区域的生境层级分布,还能发现海黍子潜在的适宜生境区域。这为今后开展海黍子资源保护和人工增殖工作提供了科学参考。     

气候变化背景下野生动物脆弱性评估方法研究进展

脆弱性评估是研究气候变化影响野生动物的重要内容,识别野生动物脆弱性,是适应和减缓气候变化影响的关键和基础。开展气候变化背景下野生动物的脆弱性评估工作,目的是为了确定易受气候变化影响的物种和明确导致物种脆弱性的因素,其评估结果有助于人类认识气候变化对野生动物的影响,为野生动物适应气候变化保护对策的制定提供科学依据。对野生动物而言(物种),脆弱性是物种受气候变化影响的程度,包括暴露度、敏感性和适应能力三大要素。其中,暴露度是由气候变化引起的外在因素,如温度、降雨量、极值天气等;敏感性是受物种自身因素影响,如种间关系、耐受性等;适应能力是物种通过自身调整来减小气候变化带来的影响,如迁移或扩散到适宜生境的能力、塑性反应和进化反应等。对近期有关气候变化背景下野生动物脆弱性评估方法予以综述,比较每种评估方法所选取指标的差异,总结在脆弱性评估中遇到的不确定性指标的处理方法,以及脆弱性评估结果在野生动物适应气候变化对策中的应用。通过总结野生动物脆弱性评估方法,以期为气候变化背景下评估我国野生动物资源的脆弱性提供参考方法。     

Evidence that the C-terminus of OprM is involved in the assembly of the VceAB-OprM efflux pump

Although the architecture of tripartite multiple drug resistance (MDR) efflux pumps of Gram-negative bacteria has been well characterized, the means by which the components recognize each other and assemble into a functional pump remains obscure. In this study we present evidence that the C-terminal domain of the Pseudomonas aeruginosa OprM and the α-helical hairpin domain of Vibrio cholerae VceA play an important role in the recognition/specificity/recruitment step in the assembly of a functional, VceAB-OprM chimeric efflux pump. To our knowledge, this is the first evidence directly linking the C-terminal domain of an outer membrane efflux protein to its recruitment during the assembly of a tripartite efflux pump.     

心脑血管疾病大额住院消费统计分析

通过对医院2004-2006年心脑血管疾病大额住院消费(消费大于50000元,以下简称大额消费)病例发病率高的前五种疾病的构成情况、药费、材料费消耗情况进行分析,认为加强大额病例中发病率高的病种的重点管理,是降低医疗费用的有效途径。建议制定常见病大额病种预定额付费方案和审查报销制度;采用适宜技术;控制药费,防止过度医疗,有效地遏制医疗费用的过快增长。     

Studies on the energy coupling sites of photophosphorylation IV. The relation of proton fluxes to the electron transport and ATP formation associated with Photosystem II

1. By using dibromothymoquinone as the electron acceptor, it is possible to isolate functionally that segment of the chloroplast electron transport chain which includes only Photosystem II and only one of the two energy conservation sites coupled to the complete chain (Coupling Site II, observed P/e₂ = 0.3–0.4). A light-dependent, reversible proton translocation reaction is associated with the electron transport pathway: H₂O → Photosystem II → dibromothymoquinone. We have studied the characteristics of this proton uptake reaction and its relationship to the electron transport and ATP formation associated with Coupling Site II.

2. The initial phase of H⁺ uptake, analyzed by a flash-yield technique, exhibits linear kinetics (0–3 s) with no sign of transient phenomena such as the very rapid initial uptake (“pH gush”) encountered in the overall Hill reaction with methylviologen. Thus the initial rate of H⁺ uptake obtained by the flash-yield method is in good agreement with the initial rate estimated from a pH change tracing obtained under continuous illumination.

3. Dibromothymoquinone reduction, observed as O₂ evolution by a similar flash-yield technique, is also linear for at least the first 5 s, the rate of O₂ evolution agreeing well with the steady-state rate observed under continuous illumination.

4. Such measurements of the initial rates of O₂ evolution and H⁺ uptake yield an H⁺/e⁻ ratio close to 0.5 for the Photosystem II partial reaction regardless of pH from 6 to 8. (Parallel experiments for the methylviologen Hill reaction yield an H⁺/e⁻ ratio of 1.7 at pH 7.6.)

5. When dibromothymoquinone is being reduced, concurrent phosphorylation (or arsenylation) markedly lowers the extent of H⁺ uptake (by 40–60%). These data, unlike earlier data obtained using the overall Hill reaction, lend themselves to an unequivocal interpretation since phosphorylation does not alter the rate of electron transport in the Photosystem II partial reaction. ADP, P_i and hexokinase, when added individually, have no effect on proton uptake in this system.

6. The involvement of a proton uptake reaction with an H⁺/e⁻ ratio of 0.5 in the Photosystem II partial reaction H₂O → Photosystem II → dibromothymoquinone strongly suggests that at least 50% of the protons produced by the oxidation of water are released to the inside of the thylakoid, thereby leading to an internal acidification. It is pointed out that the observed efficiencies for ATP formation (P/e₂) and proton uptake (H⁺/e⁻) associated with Coupling Site II can be most easily explained by the chemiosmotic hypothesis of energy coupling.     

Partial purification and properties of Galleria mellonella larvae proteolytic inhibitors acting on Metarhizium anisopliae toxic protease

Gel permeation, preparative isoelectric focusing, and affinity chromatography were used to purify three inhibitors of proteolytic activity from perchloric acid extracts of last instar Galleria mellonella larvae. Electrofocusing experiments revealed three isoinhibitors with different isoelectric points: inhibitor I-1 with p1 of pH 5.6, inhibitor I-2, pH 7.7, and inhibitor I-3 (of small inhibitory activity), pH 8.6. By affinity chromatography on trypsin-Sepharose 4B the I-1 was purified 9.7 ×, but 71.1% of inhibitory activity was lost. Molecular mass of the inhibitory complex was 12,600 Da. I-1 and I-2 are relatively stable to heat at several pHs with minor stability at pH 10. I-1 and I-2 inhibit serine proteases about 2.5 times as much as sulfhydryl proteases. In the same ratio protease P-1 and protease P-2 from Metarhizium anisopliae are inhibited.     

THE DEATH OF BIOETHICS (AS WE ONCE KNEW IT)

Fast forward 50 years into the future. A look back at what occurred in the field of bioethics since 2010 reveals that a conference in 2050 commemorated the death of bioethics. In a steady progression over the years, the field became increasingly fragmented and bureaucratized. Disagreement and dissension were rife, and this once flourishing, multidisciplinary field began to splinter in multiple ways. Prominent journals folded, one by one, and were replaced with specialized publications dealing with genethics, reproethics, nanoethics, and necroethics. Mainstream bioethics organizations also collapsed, giving way to new associations along disciplinary and sub‐disciplinary lines. Physicians established their own journals, and specialty groups broke away from more general associations of medical ethics. Lawyers also split into three separate factions, and philosophers rejected all but the most rigorous, analytic articles into their newly established journal. Matters finally came to a head with global warming, the world‐wide spread of malaria and dengue, and the cost of medical treatments out of reach for almost everyone. The result was the need to develop plans for strict rationing of medical care. At the same time, recognition emerged of the importance of the right to health and the need for global justice in health. By 2060, a spark of hope was ignited, opening the door to the resuscitation of bioethics and involvement of the global community.     

Survival and metabolism of the harpacticoid copepod Thompsonula hyaenae (Thompson) fed on different diatoms

Survival times and oxygen consumption rates have been determined for a benthic harpacticoid copepod, Thompsonula hyaenae (Thompson), when fed different algal diets. Nauplii and adults lived slightly longer on a diet of Navicula sp. than did those fed N. pelliculosa or a mixture of both naviculoid species. Mean numbers of harpacticoids hatched were significantly higher in cultures of N. pelliculosa. Metabolic rates of non-gravid females fed for one week on N. sp. were significantly lower than those fed N. pelliculosa or the mixture. There was no significant difference in oxygen uptake between animals fed N. pelliculosa and those fed the mixed culture. The smaller size and lower food energy content of N. pelliculosa are reflected in the higher respiratory rates of animals led this diatom species.Based on a thesis submitted in partial fulfillment of the M.S. degree in Marine Science at the University of South Carolina. Belle W. Baruch Institute for Marine Biology and Coastal Research Contribution No. 114. Research supported by the Oceanography Section, National Science Foundation, NSF Grant DES72-01573 A01.     

Strategy for Stabilizing Enzymes Part Two: Increasing Enzyme Stability by Selective Chemical Modification

The molecular mechanisms of change in the thermal stability of proteins modified with low molecular weight reagents are discussed. The choice of stabilization mechanisms to be used as a general strategy for increasing enzyme stability by chemical modification is addressed. Hydrophilization of nonpolar surface areas is the most simple and reliable approach to artificial stabilization of enzymes for use in applied biochemistry and biotechnology.     

Primeval cells: Possible energy-generating and cell-division mechanisms

Summary It is proposed that the first entity capable of adaptive Darwinian evolution consisted of a liposome vesicle formed of (1) abiotically produced phospholipidlike molecules; (2) a very few informational macromolecules; and (3) some abiogenic, lipid-soluble, organic molecule serving as a symporter for phosphate and protons and as a means of high-energy-bond generation. The genetic material had functions that led to the production of phospholipidlike materials (leading to growth and division of the primitive cells) and of the carrier needed for energy transduction. It is suggested that the most primitive exploitable energy source was the donation of 2H⁺+2e^– at the external face of the primitive cell. The electrons were transferred (by metal impurities) to internal sinks of organic material, thus creating, via a deficit, a protonmotive force that could drive both the active transport of phosphate and high-energy-bond formation.This model implies that proton translocation in a closed-membrane system preceded photochemical or electron transport mechanisms and that chemically transferable metabolic energy was needed at a much earlier stage in the development of life than has usually been assumed. It provides a plausible mechanism whereby cell division of the earliest protocells could have been a spontaneous process powered by the internal development of phospholipids. The stimulus for developing this evolutionary sequence was the realization that cellular life was essential if Darwinian survival of the fittest was to direct evolution toward adaptation to the external environment.     

用离散量的方法识别蛋白质的超二级结构

用离散量的方法,对2208个分辨率在2.5I以上的高精度的蛋白质结构中四类超二级结构进行了识别。从蛋白质一级序列出发,以氨基酸(20种氨基酸加一个空位)和其紧邻关联共同为参数,当序列模式固定长取8个氨基酸残基时,对“822”序列模式3交叉检验的平均预测精度达到78.1%,jack-knife检验的平均预测精度达到76.7%;当序列模式固定长取10个氨基酸残基时,对“1041”序列模式3交叉检验的平均预测精度达到83.1%,jack-knife检验的平均预测精度达到79.8%。