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1.
以同步辐射作为X射线源,在Saksbe无屏WeissenburgX-射线衍射数据收集系统上,应用磷光可逆成像屏(ImagePlate)作为记录装置,收集了天花粉蛋白正交晶体1.1A分辨率的衍射数据。经WEIS程序处理和合并后,共获得独立衍射点67.327个,占1.1A分辨率范围应有反射总数的69.8%;Rmerge=5.90%,表明数据的质量优良。这为特高分辨率天花粉蛋白的晶体结构研究奠定了坚实基础。  相似文献   

2.
以同步辐射作为X射线源,在Saksbe无屏Weissenburg X-射线衍射数据收集系统上,应用磷光可逆成像屏作为记录装置,收集了天花粉蛋白正交晶体1.1A分辨率的衍射数据。经WEIS程序处理和合并后,并获得独立衍射点67.327个,占1.1A分辨率范围应有反射总数的69.8%;Rmerge=5.90%,表明数据的质量优良,这为特高分辨率天花粉蛋白的晶体结构研究奠定了坚实基础。  相似文献   

3.
屏顶螳螂属Kishinouyeum隶属于长颈螳螂亚科Vatinae,仅分布于我国,已知2种:天目屏顶螳螂K.sinensis Ouchi,尖峰屏顶螳螂K.jianfenglingensis Hua。 1981年长乐林场采得天目屏顶螳螂的雄性,1985年9月福建武夷山自然保护区采得雄性2种,经鉴定系新种。至此本属记录增至4种,现与天目屏顶螳螂的雄性一并记述于下。模式标本等均存放在南京林业大学昆虫标本室。  相似文献   

4.
屏顶螳属Kishinouyeum由Ouchi氏建立于1938年,隶属于长颈螳科Vatidae,长颈螳亚科Vatinac.本记述采自云南西双版纳的屏顶螳属一个新种,短屏顶螳Klshinouyeum breve,sp.nov新种模式标本保存于中国科学院上海昆虫研究所.  相似文献   

5.
屏顶螳螂属一新种   总被引:3,自引:2,他引:1  
屏顶螳螂属Kishinouyeum系长颈螳螂亚科Vatinae中分布于我国的特有属,该属由Ouchi氏建立于1938年,模式种天目屏顶螳螂Kishinouyeum sinensis Ouchi系1936年采自浙江天目山。 1981年6月28日,笔者在海南尖峰岭热带林自然保护区采得屏顶螳螂雌虫一头,经鉴定系一新种。记述于下:  相似文献   

6.
本文较通俗、浅近地介绍了调制传递函数的物理概念,简述了应用于增感屏测试的大致过程。在28种增感屏的测试结果中,挑选出几种较典型的绘成曲线图,并就这些增感屏的成象性能加以简要评述。另外,作者在指出目前国内现用方法的缺点后,强调指出MTF作为影象质量定量评价的优越性,希望有关制造厂的产品说明书及质量管理部门制订的产品标准能及早采用这一严密的方法作为评定与描述增感屏成象质量的手段。  相似文献   

7.
东北地区中生代化石木异木属及其古生态   总被引:5,自引:0,他引:5  
迄今为止,我国共了现异木属(Xenoxylon)化石木10种(包括2新种),它们是X.latiporosum,X.conchylianum,X.liaoningense,X.japonicum,X.ellipticum,X.hopeiense,X.peidense,X.yixianense,X.fuxinense sp.nov.,X.huolinhenese sp.nov.。文中对该属的古生态作了  相似文献   

8.
Xiao形目8种鸟类线粒体DNA多态性研究   总被引:3,自引:0,他引:3  
李庆伟  文伟 《动物学报》1998,44(1):94-101
采用14种限制性内切酶,对Xiao形目8种鸟类线粒体DNA进行限制性片段长度多态分析,结果表明:不同种间存在基因组长度多态性,短耳Xiao为23.35kb,长耳Xiao为19.78kb斑头鸺Liu为18.62kb,红鱼Xiao为17.65kb。Xiao形目种间具有较高的遗传变异,其中仓Xiao和草Xiao的平均遗传距离为1.0%,长耳Xiao和短耳Xiao平均为10.8%,红角Xiao和领角Xia  相似文献   

9.
剂量补偿是使X连锁基因的表达水平在两性间达到平衡的过程。生物界实现剂量补偿的策略有很多种,真兽亚纲哺乳动物是随机失活雌性的一条X染色体。X失活开始于XIC,然后传播到整条染色体。XIST基因定位于XIC中,参与X失活的启动,可能是X失活决定基因。最近在人和小鼠中发现了逃避X失活的基因。探讨这些基因逃避X失活的机制有助于理解X染色体失活是如何对基因表达进行调控的。人和小鼠中有一些基因的X失活状态不同,提示了性染色体的持续不断的进化改变 。  相似文献   

10.
由凝胶电泳酶谱检测到黑曲霉149发酵液中存在两型木聚糖酶,依次为X-Ⅰ和X-Ⅱ.通过硫酸铵分级沉淀及DEAE-SephadexA50柱层析分别将X-Ⅰ、X-Ⅱ纯化到凝胶电泳均一。由SDS一凝胶电泳和浓度梯度凝胶电泳测得X-Ⅰ和X-Ⅱ的分子量分别为37kDa,76kDa,24kDa和23kDa,X-Ⅰ具有亚基。二者的含糖量分别为276%和7.3%。X-Ⅰ和X-Ⅱ最适反应温度分别为50℃和55℃,pH为46和5.2。在pH4.6~9.2和pH4.0~10.0之间X-Ⅰ、X-Ⅱ活力稳定。50℃保温24h,X-Ⅰ活力仍为100%,而X-Ⅱ的活力已降为2.8%。HgCl2和AgNO3显著抑制X-Ⅰ、X-Ⅱ的活力。X-Ⅰ与X-Ⅱ水解不同来源的木聚糖,其产物有所不同。  相似文献   

11.
The efficiency of calcium in enhancing the tolerance of beans(Phaseolus vulgaris L.) to sodium salinization was studied inpot experiments in both cool and hot seasons. In the cool seasonincreased yields of dry matter, roots, nodules and pods werepositively correlated with increased Ca application and negativelycorrelated with the Na contents of irrigation water and planttissue. The Na levels both in roots and tops declined significantlyas increased amounts of calcium were added. Ca in the rangeof 2.0 to 8.0 mmol/1 caused competitive inhibition of Na uptakeand Na translocation. At Ca levels between 0 to 2.0 mM onlyNa translocation to tops was markedly inhibited. In warm seasonsCa had no beneficial effects on bean yields at any level ofNa. On the contrary, high rates of Ca application resulted ina higher death rate.  相似文献   

12.
Biophysicochemical approaches to the solution of nanotechnology problems associated with the design of functional biomimetic nanosystems, hybrid and composite nanobiomaterials and study of their structure-function relationships. The results of studies concerned with physicochemical mechanisms of the formation of organized biomimetic nanostructures and bioinorganic nanomaterials in systems involving a bulky liquid phase and the interface (gas-liquid, solid-liquid, liquid-liquid)during the synthesis and structure formation with the participation of the components of colloid systems, inorganic nanoparticles of various composition and clusters of metals, surfactants, polyelectrolytes and their complexes are discussed. In the development of the methods for the formation of composite bioinorganic nanosystems containing inorganic nanocomponents, two major approaches were used: adsorption and incorporation into the biomolecular matrix or colloid system of presynthesized inorganic nanoparticles, as well as the synthesis of the inorganic nanophase immediately in the biomolecular system. The methods of obtaining biomaterials and nanosystems are based on the principles of biomimetics, biomineralization, self-assembly and self-organization, combination and integration of a number of synthetic and physicochemical methods (physical and chemical adsorption, Langmuir technique, the formation of polycomplexes, chemical linking, competitive interactions, and substitution of ligands in supramolecular and coordination complexes) and nanocomponents of different nature. In particular, a novel approach to the preparation of highly organized nanofilm materials was developed, which is based on the effect of self-assembly and self-organization of colloid nanoparticles during the formation of their complexes with polyfunctional biogenic ligands in the volume of the liquid phase in the absence of any surfaces and interfaces. The physical and chemical factors responsible for the formation of structurally ordered biomolecular and composite nanosystems including nano-sized components of different nature and the possibilities to control the composition, structure, and properties of resulting nanomaterials and nanosystems are discussed. The experimental methods and approaches developed may be useful in studies of structure-property relationships and basic mechanisms of structural organization and transformation at the nanoscales level in biological, artificial, and hybrid nanosystems. The problems of practical application of the synthetic methods and the corresponding nanomaterials are discussed.  相似文献   

13.
以薄壳山核桃品种‘马罕’(Caryaillinoensis‘Mahan’)的5年生嫁接苗为实验材料,研究枝条短截(1/4、1/3和1/2短截)以及枝条和主干的环剥和环割对其枝条生长及枝条和叶片中碳氮代谢物积累的影响。结果显示:经不同程度短截处理后,枝条萌芽率均显著高于对照(未经任何修剪),新枝的数量、长度和直径也均不同程度高于对照,而比叶质量及叶绿素含量总体上与对照无显著差异;经1/2和1/3短截处理后,长度0-10cm和30cm以上的新枝比例明显提高;枝条和叶片中可溶性糖含量和C/N比均高于对照、全N含量均低于对照,枝条中淀粉含量低于对照而叶片中淀粉含量高于对照。经枝条环剥和环割处理后,枝条萌芽率和比叶质量均高于对照但无显著差异,枝条平均长度增长量和叶绿素含量均显著低于对照、枝条平均直径增长量均显著高于对照;枝条和叶片中可溶性糖和淀粉含量以及C/N比均高于对照,全N含量均低于对照。经主干环剥和环割处理后,枝条的萌芽率和平均直径增长量以及比叶质量均显著高于对照,枝条平均长度增长量和叶绿素含量均显著低于对照;枝条和叶片中可溶性糖和淀粉含量以及C/N比均高于对照,枝条中全N含量高于对照而叶片中全N含量则低于对照。此外,品种‘马罕’的结果枝长度为0-30cm,其中长度0-10cm的结果枝数量最多。研究结果表明:不同短截措施均能提高薄壳山核桃的萌芽率、促进新枝伸长和增粗;而枝条和主干的环剥和环割处理对枝条萌芽率无明显促进作用,但有利于枝条增粗;不同修剪措施总体上有利于其叶片及枝条中碳水化合物的合成和积累。总体上,1/3短截及枝条和主干的适度环剥可促进品种‘马罕’结果枝的形成。  相似文献   

14.
杨庆媛  毕国华 《生态学报》2019,39(23):8939-8947
山水林田湖草生态保护修复是新时代生态文明建设和国土空间综合整治的重要内容。基于重庆市“两江四山”山水林田湖草生态保护修复工程试点,探索平行岭谷区山水林田湖草整体保护、系统修复、综合治理的科学思路以及“山岭”“谷地”“江河”差异化的生态保护修复模式与措施。研究发现:平行岭谷区特殊的地形地貌条件决定了生态系统各要素具有纵向差异大、层次性强的特点,其山水林田湖草生态保护修复宜按照“山为骨、水为脉、林田湖草为肌体”的脉络进行布局,并依据海拔高程自上而下,在“山岭”“谷地”“江河”分区分层采用差异化生态保护修复与治理模式:“山岭”区域采用“保育恢复”模式,以矿山地质环境治理、森林抚育和生物多样性保护为主,“谷地”区域采用“综合整治”模式,以土地综合整治与土壤污染修复为主,“江河”区域采用“防治结合”模式,以两江沿线地质灾害防治、水环境保护和岛屿生态系统治理为主;未来应从拓展重庆地票生态功能、实施自然资源确权制度、全面试行生态环境损害赔偿制度、健全生态保护补偿机制、建立激励引导机制等方面进行制度创新和机制创新,形成山水林田湖草生态保护修复的长效机制。  相似文献   

15.
高星 《人类学学报》2020,39(3):333-348
用火是人类独有的行为能力,对人类的生存演化至关重要。用火熟食改善了人类的营养,导致人类生物特性发生一系列改变,人口、行为、社会关系和生存方式也发生相应变化。用火使人类获得更多的生存资源,并帮助人类改变工具与用具的材料特性,如对石料做热处理,进而发明了陶器和金属工具,开启了文明的历程。人类与火的互动是一个长期、曲折的过程,经历了偶尔利用自然火、时断时续对火控制和使用、有效保存火种乃至人工取火形成用火的日常习惯,进而发展到现代无所不在、不可或缺的复杂用火。人类用火被认为始于直立人的诞生,但目前提取到的证据指向150万年前。早期人类用火证据的提取和论证存在极大的困难和挑战,需要精细的野外工作,做高精度的遗址埋藏和遗物遗迹的空间分析,须采用现代科技手段和模拟实验对地层沉积物和燃烧物证做微形态、成分、色度、磁化率、微体植物化石等尽可能多的宏观和微观分析,排除自然因素的干扰,这样得出的结论才会坚实可信。本文介绍了人类用火的历史、作用和对用火证据提取与分析的思路、方法与技术,通过一系列案例阐述人类用火的方式、发展演化过程和考古学家为破译远古人类用火的谜团所做的努力和取得的成果,以期对这项意义重大但常被忽视的研究起到推动作用。  相似文献   

16.
The postthaw motility and fertility of buffalo and cattle semen is reduced when they are cryopreserved for artificial insemination. In the present study, an attempt was made to characterize the cryogenic changes in proteases and antiprotease activities (APA) of buffalo and cattle semen because these proteolysis regulators have been reported to be associated with sperm motility and fertility. Buffalo sperm demonstrated at least two major proteases of 45 and 42 kDa and three minor proteases of 95, 52, and 33 kDa. Similarly, cattle sperm demonstrated three major proteases of 62, 45, and 42 kDa and two minor proteases of 85 and 78 kDa. Buffalo seminal plasma demonstrated at least three major proteases of 78, 68, and 62 kDa and one minor protease of 98 kDa and cattle seminal plasma demonstrated one major protease of 68 kDa and two minor proteases of 78 and 75 kDa. Except for the 45 kDa protease, most of the previously mentioned proteases were found to be metalloproteinases. Compared with fresh sperm, cryopreserved buffalo and cattle sperm demonstrated a major protease band of 52/49 kDa and the activity of this protease reduced progressively with the duration of cryopreservation. On the contrary, compared with the fresh seminal plasma, cryopreserved buffalo and cattle semen extenders displayed the presence of a new protease band of 45 kDa and demonstrated that this protease activity was leaked from buffalo and cattle cryopreserved spermatozoa. Buffalo and cattle seminal plasmas displayed at least two major APA of 86 and 26 kDa. Compared with buffalo, cattle seminal plasma demonstrated significantly greater APA. Thus, the present study demonstrated the presence of an array of proteases and APA in buffalo and cattle semen and the activities of which changed during cryopreservation. The leakage of the specific protease activity and changes in the proteases and APA might be attributed to reduced motility and fertility of cryopreserved semen in these species.  相似文献   

17.
全球木本植物叶片硅钙生态化学计量学特征   总被引:1,自引:0,他引:1  
收集全球803种木本植物叶片硅(Si)、钙(Ca)数据,研究不同木本植物生活型(常绿植物以及落叶植物、针叶植物以及阔叶植物)叶片Si、Ca元素的化学计量学特征及其与纬度、气候因子(年平均温度,年平均降水量)间的关系。结果表明:(1)全球尺度上木本植物叶片Si、Ca含量存在较大变异性,且含量均低于中国境内的研究结果;(2)不同生活型树种间存在差异,针叶树叶片Si含量及Ca/Si显著高于阔叶树,落叶树叶片Si、Ca含量及Ca/Si均显著高于常绿树种;(3)随着纬度升高、年平均温度及年平均降水量的下降,全球尺度木本植物叶片Si、Ca含量显著升高,而Ca/Si显著下降;(4)不同生活型木本植物对气候因子的响应不同,除针叶及落叶树种的Ca含量外,其余各生活型树种Si、Ca含量与纬度及气候因子显著相关,随着纬度升高而升高,随年平均温度及年平均降水量的升高而降低,且随着年平均温度的降低,常绿及阔叶树种叶片Si含量下降速度显著高于落叶及针叶树种。研究结果能够为全球尺度生态化学计量学模型的发展提供数据基础,有助于更好地理解和模拟区域乃至全球尺度上纬度和气候因子对植物叶片Si、Ca含量的影响。  相似文献   

18.
This paper develops the methodological foundations of agrolandscape-environmental studies and management of agricultural land that are based on the concept of conservation and reproduction of land and other natural resources used in agriculture, soil fertility, productive longevity of agro-ecosystems and agrolandscapes (All-Russian Williams Fodder Research Institute), and the concept of the ecological framework of agricultural landscapes and ecological–economic balance (Moscow State University, Institute of Geography Russian Academy of Sciences). An integrative understanding of the essence of agricultural lands allows us to consider them as natural agricultural systems, which have a specific structure, functions, and links and are interrelated with other agrogeo-ecosystems and geo-ecosystems that form the environment. They supply agricultural products and other side derivatives of their functioning that are associated with the development of negative processes outside their limits. The features of study, construction, and management of agricultural land are determined by the dual nature-productive essence of agrogeo-ecosystems and the presence of three subsystems in them (abiotic, biotic, and anthropogenic). A special role is played by a control and monitoring unit. Agrogeoecosystems are characterized by the presence of three types of relationships (substance-energy, informational, and management); three main functions of agrogeo-ecosystems (productive, environment-forming, and nature-protective); the ability of agrogeo-ecosystems to respond to anthropogenic impacts; the ability of adaptation and recovery; and their distinctive openness and dynamism. The priorities of studies and management of agricultural land are formulated in several principles (systematic approach, emergence, environmental framework, landscape-ecological balance, multilevel and multifactor adaptation, etc.). They are intended to improve the adaptability, sustainability, productivity, and resource-saving and environmental role of agro-ecosystems and agricultural landscapes, which is only possible by creating favorable conditions for their functioning, ensuring a balance between the productive and protective agro-ecosystems and favorable conditions for the development of soil and soil biota, for the active life of major soil-formers (perennial grasses and microbes).  相似文献   

19.
Data were obtained on 1039 recoveries of embryos from beef cows of four breeds at two locations, in clinic and on farm. General linear models procedures were utilized to determine the effects of breed, location, age of donor, dosage of follicle stimulating hormone (FSH) and the interaction of age and FSH on the following dependent variables: 1) the mean number of ova (unfertilized oocytes and embryos) recovered; 2) the mean number and percentage of embryos (fertilized; live and dead) recovered; and 3) the mean number and percentage of transferable embryos recovered. The interaction of age of donor and dosage of FSH with breed and location prevented the pooling of data over breed and location. The mean number of ova recovered was affected by age of the donor (Charolais-in clinic), or the interaction between age of donor and dosage of FSH (Polled Hereford-in clinic and -on farm and Simmental -on farm). The mean number of embryos was affected by age of donor (Polled Hereford-in clinic), dosage of FSH (Simmental-in clinic) or their interaction (Angus-on farm). The mean number of transferable embryos was affected by age of donor (Polled Hereford-in clinic and -on farm, Simmental-in clinic and Angus-on farm). General linear models procedures were utilized to determine the effects of the embryo (stage of development and quality) and the recipient (synchrony with the donor) on the rate of pregnancy. Rate of pregnancy varied with embryo quality score and synchrony of the recipient and the embryo. In conclusion, the superovulatory response was found to be highly breed-specific, and most of the variability in embryos produced was attributed to the number of ova recovered. However, the number of ova, embryos and transferable embryos recovered was further influenced by age of the donor, dosage of FSH or their interaction.  相似文献   

20.
采用L9(33)设置3因素(包括氮、磷和钾肥)3水平(N单株施用量分别为0、10和20 g,P2O5单株施用量分别为0、4和8 g,K2 O单株施用量分别为0、6和12 g)正交实验,在2015年3月和4月分2次施肥,对9个施肥处理组施肥前后2年生桂花品种‘浦城丹桂’( Osmanthus fragrans ‘Pucheng Dangui’)幼苗的生长和生理指标进行测定;并采用Pearson相关性分析法和回归分析法分别对各指标间的相关性以及各生长指标与施肥成本的关系进行分析。结果表明:与对照组( N、P2 O5和K2 O单株施用量均为0 g)相比,各处理组幼苗的株高和地径增长量及全株干质量总体上显著提高(P<0.05)。3月份至10月份,各处理组幼苗叶片的叶绿素a(Chla)和叶绿素b(Chlb)含量总体呈先升高后降低的变化趋势,并在12月份明显升高;而施肥后(6月份至12月份)各处理组叶片的Chla/Chlb比值总体呈先降低后升高的变化趋势,并且在12月份显著高于对照组。施肥后,各处理组叶片的SOD和POD活性及可溶性蛋白质含量也呈先高后低的变化趋势。相关性分析结果表明:施肥后,全株干质量与株高增长量和地径增长量呈极显著正相关(P<0.01),并与POD活性呈显著负相关;株高增长量与地径增长量和Chla/Chlb含量比值分别呈极显著和显著正相关;Chla含量与Chlb含量和可溶性蛋白质含量分别呈极显著和显著正相关。回归分析结果表明:单株施肥成本与幼苗的株高增长量和地径增长量及全株干质量均呈线性关系,且均呈极显著正相关;其中, A8(N、P2O5和K2O单株施用量分别为20、8和6 g)和A7(N、P2O5和K2O单株施用量分别为20、4和0 g)处理组的幼苗生长指标较高且差异不明显,但A8处理组的单株施肥成本高于A7处理组。研究结果表明:氮、磷和钾肥合理配施能够有效调节‘浦城丹桂’幼苗叶片的光合色素含量和抗氧化酶活性,并可促进幼苗生长。综合考虑施肥成本和生长指标,单株分别施用N和P2 O520和4 g较适宜‘浦城丹桂’幼苗的生长。  相似文献   

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