38 resultados para b-D-Galactopyranose
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The main chlorophyll a/b light-harvesting complex (LHC 11) has been isolated directly from thylakoid membranes of marine green alga (Bryopsis corticulans Setch.) by two consecutive runs of anion exchange and gel-filtration chromatography. LHC 11 proteins in the membrane extracts treated with 3% n-Octyl-b-D-glucopyranoside (OG) obtained specific binding ability on Q Sepharose column, and thus were isolated from the thylakoid membranes in a highly selective fraction. The monomeric, trimeric and oligomeric subcomplexes of LHC 11 have been obtained by fractionation of the LHC 11 mixes with sucrose density gradient ultracentrifugation. The SDS-PAGE analysis of peptide composition and absorption spectrum showed that LHC 11 monomers, trimers and oligomers prepared through this work were intact and in high purity. Our report is the first to show that it is possible to purify LHC If directly from thylakoid membranes without extensively biochemical purification.
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对虾流行病爆发以来,我国乃至世界的对虾产业一直受到各种虾病的困扰,对虾养殖业严重受阻。解决这一问题的关键是加强对虾免疫机制的研究,并在此基础上寻找对虾疾病防治的有效方法。Rel/NF-κB是一类核转录因子,在无脊椎动物的先天性免疫中,起着极为重要的作用。 本论文根据其他无脊椎动物中NF-κB家族基因Relish和Dorsal的保守氨基酸序列分别设计简并引物,从中国明对虾血细胞cDNA中先后克隆到了Relish和Dorsal基因的部分片段,并结合SMART-RACE技术分别获得了中国明对虾Relish基因(FcRelish)和Dorsal基因(FcDorsal)的cDNA 全长。 FcRelish的cDNA 全长为2157个碱基,其中开放阅读框为1512个碱基,编码504个氨基酸;FcRelish蛋白的推导分子量为57373.5 Da,理论等电点为7.00。FcDorsal基因的cDNA 全长为1627个碱基,其中开放阅读框为1071个碱基,编码357个氨基酸;FcDorsal蛋白的推导分子量为39780.7 Da,理论等电点为8.85。 分析了FcRelish基因和FcDorsal基因的在血细胞、淋巴器官、肠和肌肉等12个组织中的表达水平。组织表达结果表明FcRelish和FcDorsal在淋巴器官和血细胞中表达水平明显高于其他组织,而淋巴器官和血细胞是对虾免疫系统中最重要的两个组织,由此可以推测中国明对虾中的Relish和Dorsal可能与免疫关系密切。 本论文还利用实时荧光定量PCR技术,对灭活鳗弧菌刺激,以及WSSV病毒刺激后,对虾血细胞和淋巴器官中FcRelish基因和FcDorsal基因的转录水平进行了研究。FcRelish基因在WSSV病毒刺激后,在血细胞和淋巴器官中都出现了波浪形变化,说明FcRelish对WSSV病毒刺激产生了应答。在灭活鳗弧菌刺激后,FcRelish在血细胞中变化不明显,而在淋巴器官中出现了两次明显的下调上调交替,出现这种现象的具体原因有待探究。在WSSV病毒刺激后,血细胞和淋巴器官中FcDorsal的转录表达呈波浪形变化。而在鳗弧菌刺激后,FcDorsal在血细胞和淋巴器官中的转录均在短时间内出现明显的上调表达,说明FcDorsal对鳗弧菌非常敏感。 作为核转录因子的NF-κB蛋白的转录激活作用需要在细胞质中通过蛋白水解作用来激活,为了进一步阐明NF-κB对病菌感染的应答机制,需要进一步研究这两种转录因子在蛋白水平的变化,以便从分子水平阐明NF-κB在对虾天然免疫中的作用。
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A low molecular weight fucogalactan, obtained from the brown seaweed Laminaria japonica, was separated into three fractions (LF1, LF2 and LF3) by DEAE-Sepharose FF column chromatography. All three fractions contained predominantly fucose, sulfate group and galactose. The results showed that the main fraction LF2 consisted of L-fucose, D-galactose and sulfate at a molar ratio 6:1:9. Structural study on the LF2 was carried out by NMR spectroscopy. The backbone of LF2 was primarily (1 -> 3)-linked alpha-L-fucopyranose residues (75%) and a few (1 -> 4)-alpha-L-fucopyranose linkages (25%). The branch points were at C-4 of 3-linked alpha-L-fucopyranose residues by beta-D-galactopyranose unites (35%, molar ratio) or at C-2 of 3-linked alpha-L-fucopyranose residues by non-reducing terminal fucose unites (65%, molar ratio). Sulfate groups occupied at position C-4 or C-2, sometimes C-2, 4 to fucose residues, and C-3 and/or C-4 to galactose residues. The structure of LF2 was supposed as following: [GRAPHICS] (C) 2010 Elsevier B.V. All rights reserved.
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1)依据镜质组反射率(或由沥青、无定形干酪根换算成的镜质组反射率)拟合计算沉积盆地及生油层古地温是一种比较实用而又简便可行的方法。2)从十二口井井温数据分析,除X6井(2.0℃/100M)和X1井(2.05℃/100M)外,其它十口井的现地温梯度均小于2℃/100M。塔里木盆地的现地温梯度是较低的。3)拟合计算古地温的结果表明,塔B和塔A地区古地温梯度偏低半呈下降的趋势:塔B地区古生代隆起区古地温梯度为3.5℃/100M,凹陷区为3.0℃/100M,中生代古地温梯度为2.5-2.7℃/100M,新生代古地温梯度为2.0-2.2℃/100M。塔A及塔C地区:古生代隆起区的古地温梯度为3.5℃/100M,凹陷区为3.0℃/100M;中生代古地温梯度为2.5℃/100M,新生代为2.0-2.2℃/100M,今地温梯度为2.0℃/100M。4)古地温拟合计算结果表明:塔B地区志留系至二叠系地层基本被剥蚀,有的部位下古地层也遭到部分剥蚀。寒武-奥陶系总厚度在3000-4000米以上,生油层的生油期持续时间很长。寒武系底的生油期从寒武纪末到石炭纪(522-342Ma),目前普遍处在干气阶段。奥陶系底的生油期从奥陶纪末期一直持续到第三纪,90%的地区生油高峰期在泥盆纪末(早海西运动以后)之后(见图3-12),目前普遍处于凝析油-湿气阶段。塔A地区志留、泥盆系基本被剥蚀殆尽,而寒武-奥陶系基本未被剥蚀,总厚度在2000-4000米之间。寒武系底的生油期从寒武纪末期到泥盆纪(511-362Ma),至今大部分处于生气阶段。奥陶系底的生油期从泥盆纪一直到第三纪(404-40Ma),约30%的地区生油高峰期在泥盆纪末(早海西运动)之后(见图3-?),至今部分生油岩处于生气阶段。由于受加里东和海西运动的影响,塔A和塔B地区古生界地层普遍存在“二次生油”的现象。两地区石炭-二叠系一般在第三纪开始生油,生油期普遍较短。相对塔B和塔A地工而言,塔C地区受构造运动而遭剥蚀的程度要小得多。寒武-奥陶系总厚度范围为2100-8200米,因此生油层的生油期持续时间很长。寒武系底的生油期从中寒武世到石炭纪(536.5-305Ma)。奥陶系底的生油期从晚奥陶世一直到第三纪晚期(439.5-16.5Ma),仅少数地区生油高峰期在泥盆纪末(早海西运动)之后,目前大部分处于凝析油-湿气到干气阶段。石炭、二叠、三叠及侏罗系生油层目前大都处于“生油窗”内。总之,本区是塔A和塔B地区的主要油源区。5)通过对有机包裹体类型和荧光性质的鉴定、数量的统计、以及盐水溶液包裹体均一温度的测定,可以初步了解有机质热演化程度及含油气情况。6)对中生代样品,Tmax反映的成熟度与其它参数基本一致,而对于古生代样品,由于样品成熟度增大,Tmax失去指示成熟度的作用。原油和生油岩生物标志化合物反映的成熟度基本上与其它指标一致,因此在缺乏反射率资料的地区,可用生物标志化合物近似反映成熟度的变化。
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中国是受沙漠化影响最严重的国家之一。梭梭(Haloxylon ammodendronBunge)是藜科梭梭属多年生小乔木或灌木,作为荒漠地区主要的建群种和优良固沙植物,梭梭在维持荒漠生态系统的结构与功能、防止土地沙漠化、改善小气候方面具有十分重要的作用。近年来,由于不合理地开发利用,大面积的天然梭梭林衰退甚至死亡。然而,我们对于梭梭种群的空间分布和遗传结构所知甚少。本文拟通过对自然梭梭种群的空间格局、遗传结构、遗传结构的空间分布、以及种子种群与地面植被种群的遗传比较的研究,探讨种群的空间结构特征及成因,评价种群遗传多样性水平,了解遗传多样性在种群内、种群间的分布情况以及在空间上的分布格局,预测种群的遗传潜能,并为制定合理的保护、利用策略提供理论依据。 1.对古尔班通古特沙漠东南部地区处于不同演替阶段的四个梭梭种群的分布格局和种群动态进行了考察。结果表明,不同样地中梭梭种群的幼苗(<0.5m)和幼树( 0,5-lm)均呈聚集分布,样地A、B、D中的成熟个体(>1m)也呈聚集分布,样地c中的成熟个体呈随机分布,从整个种群来看,所有梭梭种群均呈聚集分布。种群的龄级结构图表明样地A和c中的梭梭种群表现为稳定型结构,可进行持续更新,虽然样地D中的种群幼苗和幼树数量较少,但这种现象是暂时的,种群仍具有持续更新的能力,样地B中的种群表现为衰退型结构。 2.利用空间自相关分析检测上述四个种群的空间遗传结构,结果表明,四个种群中的成株均无显著的空间自相关。虽然梭梭的种子散布能力有限,但花粉流有可能是空间遗传结构不显著的原因之一;另一个可能的解释是在种群更新和发展过程中,由于种内竞争的增强而发生了自疏现象。 3.利用ISSR标记对新疆和内蒙古境内共9个种群的遗传结构进行研究。8个引物共扩增出219条带,其中184条(84%)具多态性,种群的遗传多样性水平较高,通过AMOVA分析表明大部分遗传多样性分布在种群内,区域间、种群间的遗传变异均很小。梭梭种群较高的遗传多样性水平可能源于对异质、高胁迫环境的长期适应,而种群间遗传分异低的主要原因是种群间存在强大的基因流。 4.对5个梭梭种群的地面植被和种子库的遗传结构进行了比较分析,并调查了其中3个种群地面植被和种子库的空间遗传结构。结果表明,在所有种群中,地面植被和种子库的遗传多样性水平相似,而地面植被的遗传分异高于种子库的遗传分异:二者在遗传结构的空间分布上也不相同,地面植被种群无显著的空间自相关,而种子库种群在第一距离级上( 0-10 m)呈显著正相关。研究结果表明梭梭种群的种子库有能力保持种群的遗传多样性并减弱种群的遗传分化。 5.研究结果建议,由于现存梭梭种群和其潜在种群(种子种群)仍保持了较高的遗传多样性,种群间的基因交换并没有受到阻碍,因此对梭梭的保护可以与生态恢复工作同时进行。在具体工作中,应充分考虑种群的遗传结构特征及其空间格局,选取适合的种群或种子资源进行恢复与重建,并保持一定水平的种群大小,才能实现种群的稳定发展以及在高胁迫环境中的长期存活。 荒漠生态系统植被结构简单,环境压力大,对荒漠地区主要建群种和优势种植物的空间分布和遗传结构进行研究对于探讨在胁迫环境中各种进化力量(如选择、突变、迁移、漂变)的作用机制有重要意义,并为荒漠生态系统的恢复与重建工作提供了有价值的信息。在本文中,对荒漠植物在较大地理范围内的遗传结构研究、通过空间自相关分析进行种群的空间遗传结构研究、地面植被种群与种子库种群在遗传结构、空间遗传结构上的比较研究在国内均为首例。这些研究结果为进一步深入探讨荒漠植物生态适应与进化的分子机制奠定了基础。
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本研究测定了懒猴属( Nycticebus) D 环的部分序列和细胞色素b 基因的全序列(1 140 bp) , 分析了 该属物种之间的系统发育进化关系。在DNA 水平上, 序列分析结果一致地提供了新的分类学证据: 支持Rata2 jszczak 和Groves 的观点, 即N1intermedus 只是N1 pygmaeus 的成体(Ratajszczak , 1998 ; Groves , 1971) 。对两种 序列的数据做了联合及个别分析, 获得相似的系统树, 支持懒猴属由两个单系群组成: 第一群由N1 pygmaeus 聚成, 第二群由N1coucang 聚成。该结果也提供了新的分子遗传证据, 支持懒猴属由N1coucang 和 N1 pygmaeus 两物种组成。
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Data on intergroup-interactions (I-I) were collected in 5 seasonally provisioned groups (A, B, D, D-1, and E) of Tibetan macaques (Macaca Thibetana) at Mt. Emei in three 70-day periods between 1991 April-June (P1), September-November (P2), December-1992 February (P3). The I-I were categorized as forewarning made by high-ranking males (including Branch Shaking and/or Loud Calls), long-distance interactions in space (specified by changes in their foraging movements), and close encounters (with Affinitive Behavior, Male's Herding Female, Sexual Interaction, Severe Conflict, Adult Male-male Conflict, Opportunistic Advance and Retreat, etc. performed by different age-sex classes). From periods Fl to P3, the I-I rate decreased with reduction in population density as a positive correlate of food clumpedness or the number of potential feeders along a pedestrian trail. On the other hand, from the birth season (BS, represented by P1 and P3) to the mating season (MS, represented by P2) the dominance relation between groups, which produced a winner and a loser in the encounters, became obscure; the proportion of close encounters in the I-I increased; the asymmetry (local groups over intruders) of forewarning signals disappeared; the rate of branch shaking decreased; and sometimes intergroup cohesion appeared. Considering that sexual interactions also occurred between the encountering groups, above changes in intergroup behaviors may be explained with a model of the way in which the competition for food (exclusion) and the sexual attractiveness between opposite sexes were in a dynamic equilibrium among the groups, with the former outweighing the latter in the BS, and conversely in the MS. Females made 93% of severe conflicts, which occurred in 18% of close encounters. Groups fissioned in the recent past shared the same home range, and showed the highest hostility to each other by females. In conspicuous contrast with females' great interest in intergroup food/range competition, adult male-male conflicts that were normally without body contact occurred in 66% bf close encounters; high-ranking male herding of females, which is typical in baboons, appeared in 83% of close encounters, and showed no changes with season and sexual weight-dimorphism; peripheral juvenile and subadult males were the main performers of the affinitive behaviors, opportunistic advance and retreat, and guarding at the border. In brief, all males appeared to "sit on the fence" at the border, likely holding out hope of gaining the favor of females both within and outside the group. Thus, females and males attempted to maximize reproductive values in different ways, just as expected by Darwin-Trivers' theory of sexual selection. In addition, group fission was observed in the largest and highest-ranking group for two times (both in the MS) when its size increased to a certain level, and the mother group kept their dominant position in size and rank among the groups that might encounter, suggesting that fission takes a way of discarding the "superfluous part" in order to balance the cost of competition for food and mates within a group, and the benefit of cooperation to access the resources for animals in the mother group. (C) 1997 Wiley-Liss, Inc.
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试验鱼以投喂饲料的不同和是否注射抗原共分为10组,即免疫组:A、B、C、D、E组,免疫对照组:a、b、c、de、组,饲料对照组:A、a组。饲料试验组B、C、D、E、bc、、d、e组。其中,饲料对照组以豆粕和鱼粉为基础蛋白源,饲料试验组分别以双低菜籽粕和普通菜籽粕等氮替代对照组中50%(B、b;D、d)和100%(C、c;E、e)的豆粕蛋白,测定异育银鲫血液白细胞和头肾吞噬细胞的吞噬活性、血清溶菌酶活性、血清补体(C3,C4)含量、血清凝集抗体效价及免疫保护率。结果表明:从免疫后21 d开始,饲料试验组E、
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Full-length and partial genome sequences of four members of the genus Aquareovirus, family Reoviridae (Golden shiner reovirus, Grass carp reovirus, Striped bass reovirus and golden ide reovirus) were characterized. Based on sequence comparison, the unclassified Grass carp reovirus was shown to be a member of the species Aquareovirus C The status of golden ide reovirus, another unclassified aquareovirus, was also examined. Sequence analysis showed that it did not belong to the species Aquareovirus A or C, but assessment of its relationship to the species Aquareovirus B, D, E and F was hampered by the absence of genetic data from these species. In agreement with previous reports of ultrastructural resemblance between aquareoviruses and orthoreoviruses, genetic analysis revealed homology in the genes of the two groups. This homology concerned eight of the 11 segments of the aquareovirus genome (amino acid identity 17-42%), and similar genetic organization was observed in two other segments. The conserved terminal sequences in the genomes of members of the two groups were also similar. These data are undoubtedly an indication of the common evolutionary origin of these viruses. This clear genetic relatedness between members of distinct genera is unique within the family Reoviridae. Such a genetic relationship is usually observed between members of a single genus. However, the current taxonomic classification of aquareoviruses and orthoreoviruses in two different genera is supported by a number of characteristics, including their distinct G+C contents, unequal numbers of genome segments, absence of an antigenic relationship, different cytopathic effects and specific econiches.