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991.
单克隆抗体技术作为病毒病检测与防治的有力武器,在人类、畜牧兽禽等的病毒病控制与预防中发挥出日益显著的作用.从二十世纪八十年代中期Chinchar等研制蛙虹彩病毒(Frog virus 3, FV3)单抗开始[1],这一技术及其研究成果也运用于水生动物病毒学研究中.尤其是近年,人们对水产品蛋白质不断增长的需求,使水产养殖业呈现突飞猛进的发展势头,但普遍流行的水生动物病毒病已造成巨大经济损失.滥用药物不仅防治效果差,而且严重污染水体及生态系统.利用生物技术和环保方式对水生动物病毒病进行防治,就成为人们关注的热点.因此,单抗技术在水生动物病毒病研究中得到越来越广泛的运用,并有新的进展.本文就此作一综述.  相似文献   
992.
Five compounds were isolated from Buxus microphylla Sieb. et Zucc. Based on the physico-chemical constants and spectral analysis (IR, MS, 1H-NMR and 13C-NMR), they were identified as cycloprotobuxinamine ( Ⅰ ), buxmicrophylline A ( Ⅱ ), buxtauine M ( Ⅲ ), isoscopoletin (Ⅳ) and epi-lupeol ( Ⅴ ). ( Ⅰ ) and ( Ⅱ ) were new compounds. The structure of buxmicrophylline ( Ⅱ ) was confirmed by X-ray crystallographic analysis.  相似文献   
993.
Pinaceae Lindl., containing 10 genera and about 235 species, is the largest family in the extant conifers. It widely spreads in the Northern Hemisphere and plays a very important role in coniferous forests occurring in temperate to subtropical mountains. Numerous studies on this family have been carried out and the data dealing with many aspects of biosystematics of the Pinaceae have been accumulated. Based on the principle of unity of phylogeny and distribution of plants, and on the data from the studies of biosystematics of the Pinaceae, the present paper discusses the problems related to geographic distribution and phylogeny of the family in three respects as follows: (1) Floristic division of the Pinaceae is made based on Farjon's work (1990). Six regions and four subregions are outlined (Fig. 1). These are: I. the Mediterranean Region; II. the Eastern European and Siberian Region;III. the Eastern Asiatic Region, which can be further divided into two subregions, i. e. III a. the Northern Eastern Asiatic Subregion and III b. the Himalayas and Southern Eastern Asiatic Subregion; IV. the Western Northern American Region which also contains two subregions, namely IV a. the Northwestern North American Subregion and IV b. the Southwestern North American Subregion V. the Northern North American Region; VI. the Southeastern North American Region. The numbers of species occurring in all these floristic regions are shown in Table 1. The statistic results show that the Subregion III b is currently the richest in species of the Pinaceae. All the living genera are represented in this subregion, including three endemic genera: Keteleeria, Cathaya and Pseudolarix. The second richest area is the Subregion IV b which contains a great number of species. In fact, the two subregions are considered as counterparts. In addition, the Subregion III a and Subregion IV a, the Region II and Region V are also pairs of counterparts. The former pair has fewer but widely spread species, most of which are comparatively young probably developed from the extended refuges after the glacier period of the Quaternary. (2) The geographic distribution of all the genera are described and compared. The maps of their present ranges and their fossil localities are drawn. The four generic distribution patterns are detected: a) North Temperate areal type: containing four genera: Pinus, Picea, Larix and Abies; b) East Asian and North American disjunct areal type: including two genera:Tsuga and Pseudotsuga; c)Mediterranea-Himalayan areal type: containing only one genus: Cedrus; d) Himalayas and Southern Eastern Asiatic areal type: containing three genera: Keteleeria, Cathaya and Pseudolarix. The latter two are endemic to China. (3) The origin, differentiation and early migration of the Pinaceae are studied through the analyses of the data mainly on fossils ( including both extinct and extant genera ), paleogeography, paleoclimate and paleoflora. The main opinions of the present author are as follows: ① The Pinaceae was a large group of plants in geological stages, encompassing many genera with most of them becoming extinct after Mesozoic. The morden Pinaceae may be the offsprings of a few temperate-adapted members, However, they surpassed their ancestors and developed into the main components of current coniferous forests in north temperate zone to north subtropical mountainous regions. The modern Pinaceae is probably a derived group and its prosperity could be related to the emergence of temperate flora. ② Although the origin of the Pinaceae could be traced back to Jurassic or even Triassic, the occurrence of the modern genera of Pinaceae was merely from the Early Cretaceous to the Tertiary. ③ The genera of the Pinaceae may be differentiated in different stages and places. Pinus is possibly the earliest differentiated one among the extant genera. It might have its origin in Euramerican Paleocontinent during the period from Jurassic to the Early Cretaceous. The other genera might have not been diverged from their ancestral complex until the Late Cretaceous to the Tertiary, with one or two of them even until the Middle Tertiary. The place of the differentiation of these genera are supposed to be also restricted in Laurasia, but I intend to conside that it shifted to the North Pacific floristic region, where is currently the greatest diversity of the Pinaceae taxa. ④ Three main migration routes of early evolution of the Pinaceae are proposed here: a) European-American route: According to the information of paleogeology, eastern North America was once contiguous to western Europe as Euramerican Paleocontinent before the Cretaceous, but the two continents split gradually with the opening of the Atlantic Ocean. At the end of the Late Cretaceous, the two parts were still connected through Greenland and an Atlantic floristic region existed. The Euramerican Paleocontinent may be the place for differentiation of the Pinaceae in early stage, while the Atlantic floristic region was a migration route in the modern Pinaceae. b) Eurasiatic route: Before the Late Cretaceous, the Tethys Sea stretched from west to southeast of Eurasia. In the area north of the Tethys Sea, plants could disperse freely. By the Late Cretaceous, however, the existence of the West Siberian Sea and Turgai Straits restricted the exchanging of the Pinaceae plants between Europe and southeast Asia mainly to the coast of the Tethys Sea. Although the Tethys Sea disappeared later and the Himalayas arose, the area along the original coast of the Tethys Sea also remained as a route which played an important role in the dispersal and distribution of the modern Pinaceae. c) Paleoberingian route: At the beginning of the Late Cretaceous, eastern Asia was contiguous to the west of North America through Paleoberingia and formed “Asia-America” landmass. This situation did not cease till Pliocene. The paleoberingian route existed on the basis of this situation, playing a main role in dispersal of the morden Pinaceae between eastern Asia and western North America. There are many taxa ( generic or infrageneric ) in the modern Pinaceae with the patterns which belong to “East Asian and North American disjunct areal type” . The formation of the pattern ismostly related to the existence of the Paleoberingian route. ⑤ The existence of the above mentioned three migration routes is the basis for wide distribution of the Pinaceae in the Northern Hemisphere. In addition, the distribution patterns of the extant genera have formed as the results of the tectonic movements and the changes in paleoclimate and paleoflora since the Tertiary. 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Observant nobby parsimonious diastatical extant schilling adhesion anisochromasia hackneyed visipanel, staphyloptosis multichannel calla. Photomicrograph alkaluria felicity; saggar chlorinating. Armrest probably,.   相似文献   
994.
995.
部分双壳贝类的线粒体遗传方式不同于标准的母系遗传(SMI),被称为双单性遗传现象(DUI)。池蝶蚌(Hyriopsis schlegelii)是淡水双壳贝类,是否存在双单性遗传现象?本文采用普通PCR扩增、SHOT-GUN测序及软件拼接获得了雄性池蝶蚌线粒体基因组(以下简称Hs-mtDNA)全序列,并与本实验室已报道的雌性池蝶蚌线粒体基因组全序列进行差异性分析。结果表明,雄性和雌性Hs-mtDNA全长分别为15961 bp和15939 bp,雄性比雌性长22 bp,雌雄线粒体基因组成与排列顺序一致。各蛋白编码基因的碱基数目均一致,碱基转换率为1.01%~7.34%,颠换率为0.00%~0.62%,氨基酸差异率为0.00%~9.35%;其中,COX1基因变异率为2.72%;COX2基因碱基变异率最高,达7.50%,雄性COX2的3'末端没有出现编码延伸区。雄性12S rRNA基因发生5 bp的碱基转换,差异率为0.6%;16S rRNA基因比雌性长9 bp,碱基差异率仅为1.2%。雌雄tRNA-His均位于H链上,介于COX2与ND3之间,没有出现位置的差异性。雌雄Hs-mtDNA的非编码区共有28个1~393 bp的片段,但未见控制区。在tRNA-Glu与tRNA-Tyr间有一段长393 bp的非编码区存在蛋白质翻译功能,但非雄性特异性蛋白。以COX1基因建立系统进化树,池蝶蚌和三角帆蚌(H.cumingii)聚在一起,而含有双单性遗传现象的无齿蚌属的Pyganodon grandis、小方蚌亚科的Venustaconcha ellipsiformis及小方形蚌属的Quadrula quadrula三者雄性聚为一支,雌性聚为一支。因此,雌雄池蝶蚌线粒体存在一定的差异性,但其差异要比其他具有双单性遗传现象的淡水双壳类小得多,且池蝶蚌线粒体遗传可能不存在双单性遗传现象。  相似文献   
996.
Autonomous crack healing of cementitious composite, a construction material that is susceptible to cracking, is of great significance to improve the serviceability and to prolong the longevity of concrete structures. In this study, the St-DVB microcapsules enclosing epoxy resins as the adhesive agent were embedded in cement paste to achieve self-healing capability. The self-healing efficiency was firstly assessed by mechanical restoration of the damaging specimens after being matured. The flexural and compressive configurations were both used to stimulate the localized and distributed cracks respectively. The effects of some factors, including the content of microcapsules, the curing conditions and the degree of damage on the healing efficiency were investigated. Water absorption was innovatively proposed to monitor and characterize the evolution of crack networks during the healing process. The healing cracks were observed by SEM-EDS following. The results demonstrated that the capsule-containing cement paste can achieve the various mechanical restorations depending on the curing condition and the degree of damage. But the voids generated by the surfactants compromised the strength. Though no noticeable improved stiffness obtained, the increasing fracture energy was seen particularly for the specimen acquiring 60% pre-damage. The sorptivity and amount of water decreased with cracks healing by the adhesive, which contributed to cut off and block ingress of water. The micrographs by SEM-EDS also validated that the cracks were bridged by the hardened epoxy as the dominated elements of C and O accounted for 95% by mass in the nearby cracks.  相似文献   
997.
Shoot pruning could cause short-term damages to vines. In response to damage, tyloses develop in shoot xylem vessels interfering free water and mineral transportation. In this study, the tylosis development at different nodes of the current-year and perennial shoots of sixty three-year-old grapevines (Vitis vinifera L.) after pruning was investigated. The results showed that tyloses at the nodes closest to the trunk developed rapidly; and tylosis development initiated at the time when the size of vessel-ray pit was greater than that of parenchyma cell-parenchyma cell pit. In current-year shoots, tyloses were formed in up to 87% of the vessels, and 40% of the vessels were completely blocked by tyloses. In wound-induced perennial shoots, 30% of the vessels were completely blocked by tyloses. When few vessels were blocked by tyloses, new vessels could differentiate, and water transportation system may be restored. However, when tyloses developed in a large number of vessels and the large number of the vessels were blocked, the original capability of water transport was decreased (the largest decrease was 21.1% in this study), resulting in dehiscence or shrinkage cracking in this area. The study proved that the tylosis formation in functional vessels limited the water transport efficiency.  相似文献   
998.
999.
Store-operated Ca2+ entry (SOCE) machinery, including Orai channels, TRPCs, and STIM1, is key to cellular calcium homeostasis. The following characteristics of mitochondria are involved in the physiological and pathological regulation of cells: mitochondria mediate calcium uptake through calcium uniporters; mitochondria are regulated by mitochondrial dynamic related proteins (OPA1, MFN1/2, and DRP1) and form mitochondrial networks through continuous fission and fusion; mitochondria supply NADH to the electron transport chain through the Krebs cycle to produce ATP; under stress, mitochondria will produce excessive reactive oxygen species to regulate mitochondria-endoplasmic reticulum interactions and the related signalling pathways. Both SOCE and mitochondria play critical roles in mediating cardiac hypertrophy, diabetic cardiomyopathy, and cardiac ischaemia-reperfusion injury. All the mitochondrial characteristics mentioned above are determinants of SOCE activity, and vice versa. Ca2+ signalling dictates the reciprocal regulation between mitochondria and SOCE under the specific pathological conditions of cardiomyocytes. The coupling of mitochondria and SOCE is essential for various pathophysiological processes in the heart. Herein, we review the research focussing on the reciprocal regulation between mitochondria and SOCE and provide potential interplay patterns in cardiac diseases.  相似文献   
1000.
Niche differentiation has long been identified as an essential stabilizing mechanism for the coexistence of sympatric species. Using camera trapping data obtained during 2012–2016, we identified Macaca leonina and M. mulatta as the dominant macaque species in the Naban River Watershed National Nature Reserve (NRW-NNR), a tropical forest in southwestern China. In general, M. leonina exhibited a wider distribution and greater niche breadth than co-occurring M. mulatta. According to a fitted maximum entropy model (MaxEnt), M. leonina was predicted to predominantly occur in forest at higher elevation, whereas M. mulatta was predicted at lower elevation; the broadleaved evergreen forest was predicted as the most suitable vegetation for both species to inhabit, while the unsuitable area was bordered by rubber plantation, in which both food scarcity and human disturbance restricted the movement of macaques. Although the niches of these two species highly overlapped across space and time, we also found evidence for their spatiotemporal niche differentiation. When the two species inhabited independent areas with different elevations and vegetation, they maintained a similar activity pattern; however, in the zones of overlap, their activity patterns differed significantly. Further comparative field studies of these two macaques, considering other niche dimensions, are required to ensure their coexistence and long-term conservation.  相似文献   
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