海南岛蕨类植物的分类、区系地理与保育

摘要 "基于形态－地理学方法，通过野外调查，结合大量标本研究，在前人研究的基础上，对海南蕨类植物的分类进行了进一步修订;主要根据蕨类植物的现代地理分布，结合古生物学等有关资料，初步探讨了海南蕨类植物的区系性质与起源;根据IUCN2001年红色名录的等级和标准，对海南濒危蕨类植物的现状进行了初步评估，讨论了海南蕨类植物的受威胁原因，提出了有关保护的对策。主要结果如下： 1. 海南现有蕨类植物56科140属439个种及种下分类群（包括421种、15变种、2亚种和1变型），其中包括1个中国分布新记录和27个海南分布新记录，1新种――海南符藤蕨Teratophyllum hainanense;另有11个名称首次被处理为异名;澄清了海南假瘤蕨Phymatopteris hainanensis和圆顶假瘤蕨P. obtusa的模式问题，为滇桂三相蕨Ataxipteris dianguiensis、海南假瘤蕨P. hainanensis和浅杯鳞盖蕨Microlepia ampla指定了后选模式。 2. 海南蕨类区系具有以下特点：i. 以水龙骨科Polypodiaceae、金星蕨科Thelypteridaceae、铁角蕨科Aspleniaceae、叉蕨科Tectariaceae和观音座莲科Angiopteridaceae为表征科;ii. 明显的热带性质，科的97.5％、属的92.5％、种的83.6％为热带分布成分;iii. 很高的物种多样性与物种密度，但属内种系贫乏;iv. 与中南半岛的联系最为紧密，海南140个蕨类属中有136个与中南半岛共有，两地属的相似性系数达到87.2%;v. 海南蕨类区系就地起源于华夏古陆，起源时间可以追溯至早石炭世以前。 3. 海南439种蕨类（包括421种、15变种、2亚种和1变型）中，183种为常见蕨类，113种属于资料缺乏的种类（DD），47种属于近危（NT），53种属于易危（VU），37种属于濒危（EN），6种属于极危（CR）。海南的受威胁蕨类植物有96种，海南的绝大部分受威胁蕨类植物都生于保护区以内或得到有效保护的林区之内，已初步得到保护。导致海南96种蕨类受威胁的因素，除了植物本身的生物生态学特性和地理分布上的限制外，主要是人类活动的影响，特别是海南森林在上个世纪被大规模砍伐。为了保护这些受威胁植物，应加强保护区和林区的管理，实施就地保护，积极开展迁地保护和人工繁殖。 "

中国蕨类植物保护生物地理学研究

保护生物地理学（Conservation biogeography）就是运用生物地理学的原理、理论和分析方法，特别是那些有关物种分布格局的信息，去解决生物多样性保护的相关问题，是当前生物多样性及其保护生物学研究领域的热点。通过构建中国蕨类植物物种及分布数据库得知，中国现有蕨类植物63科，221属，2456种，其中有1218种属于中国特有（中国蕨类总数约50%），3种蕨类植物为外来种。科的统计表明：最大的科为鳞毛蕨科、蹄盖蕨科、金星蕨科和水龙骨科4个科所包含的种类占全国总种数的51.5%。鳞毛蕨科、蹄盖蕨科、金星蕨科、水龙骨科、铁角蕨科、凤尾蕨科、碗蕨科、中国蕨科、叉蕨科、观音座莲科等十个大科所含种数占了中国特有种总数的80%。云南、四川、贵州、广西、台湾、湖南、西藏等省区是中国蕨类植物种类数量及中国特有种数量较多的地区；全国有22个省区拥有地方特有种，地方特有蕨类植物数量由西向东、由南向北逐渐递减，云南、台湾、西藏、海南等四省区的地方特有蕨类植物种数占各省区蕨类植物总数10%以上，反映了青藏高原隆起及岛屿现象对中国特有蕨类植物分化的影响。 中国蕨类植物与各地理、环境及气候因子的相关性分析结果表明：（1）随着经度、纬度的增加， 蕨类植物物种总数及中国特有蕨类植物总数具有减少的趋势；（2）蕨类植物在海拔1000-1600米之间、特有蕨类植物在海拔700-2100米之间具有最大的多样性，此区间外随着海拔的降低及升高，物种丰富度依次降低；（3）气候因子特别是一月均温、年均温、相对湿度、年降雨量等因素对蕨类植物及中国特有蕨类植物均具有较大的影响，与最热月均温成低度线性相关或相关不显著；（4）地形因子是影响蕨类植物多样性的一个独立因素，地形条件越复杂，蕨类植物种类及中国特有蕨类植物种类越丰富。 运用SPSS统计分析软件分析了中国蕨类植物在各省之间种的相似性，以省区为单元对中国各省区蕨类植物物种组成进行了聚类分析，最后结果划分成：①南方蕨类植物区（包括横断山—青藏高原亚区、华中亚区、华东亚区、华南亚区）和北方蕨类植物区（包括东北—华北—西北亚区、秦岭亚区、江淮亚区）。 中国蕨类植物区系地理成分分析结果表明：（1）中国—喜马拉雅分布（40.86%）、热带亚洲分布（30.95%）、东亚分布（12.77%）和中国—日本分布（8.24%）构成中国蕨类植物区系成分的主体；在洲际关系方面，中国蕨类植物与大洋洲的蕨类植物关系最为紧密，共有种最多，达94种；与南美洲共有的蕨类植物种类最少，仅32种。（2）基于地理成分的聚类分析结果表明，可将我国蕨类植物区系地理区划为代表温带亚洲成分的（特别是中亚、西亚地中海分布成分）西北温带亚洲植物区、代表古热带成分的华南古热带植物区和代表广义东亚成分的东亚植物区，东亚植物区可继续下分为中国东北—俄罗斯远东亚区（该区分布有大量的东亚－北美间断分布类型）、中国—日本植物亚区、中国—喜马拉雅植物亚区。 运用IUCN濒危物种等级对中国蕨类植物及其国家重点保护蕨类植物进行了现状评估，结果表明：可能灭绝（EX）的2种，极危（CR）的蕨类植物有33种，属于濒危（EN）的蕨类植物51种，属于易危（VU）的蕨类植物有109种，接近受危（NT）的蕨类植物158种，需予关注（LC）的845种，数据不足（DD）的1255种。对国家重点保护蕨类植物的保护级别提出部分变更的建议，对部分没有列入保护名录珍稀蕨类提出保护的建议，并就建议保护级别变更和增加保护的种类进行了必要的说明。

云南18 个民族Y染色体双等位基因单倍型频率的主成分分析

世居云南的少数民族中,壮、傣、水、布依、布朗、德昂、佤、彝、白、怒、哈尼、傈僳、拉祜、纳西、景颇、阿昌、基 诺和独龙18 个民族是由“羌”、“濮”、“越”3 大部落群体演化而来,是云南的土著居民。利用PCR2RFL P 方法对这18 个土著民族进行Y染色体上13 个双等位基因位点进行基因分型。结果显示,不同历史族源的民族群体在Y染 色体双等位基因单倍型分布上具有一定的差异:在百越后裔民族群体中以单倍型H11 、H12 为主要分布;在氐羌后 裔民族中以单倍型H5 、H6 和H8 为主要分布;在百濮后裔民族群体中主要单倍型分布为H6 、H8 和H11 。进一步 主成分分析表明,百越后裔民族群体和氐羌后裔民族在主成分图上聚为两组,提示父系基因库有不同的来源,与历 史记载相印证。

Rapid evolution of an X-linked microRNA cluster in primates

MicroRNAs (miRNAs) are a growing class of small RNAs ( about 22 nt) that play crucial regulatory roles in the genome by targeting mRNAs for cleavage or translational repression. Most of the identified miRNAs are highly conserved among species, indicating

Comparative study of three short-chain neurotoxins from the venom of Naja kaouthia (Yunnan, China)

Three short-chain neurotoxins named NT-I, NT-II, and NT-III were purified from the venom of Naja kaouthia, a snake distributed throughout the south of Yunnan province, China, by a series of chromatographic steps, including an FPLC Resource S column. Their molecular weights, determined by matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF) MS, were 6952.19 Da, 6854.92 Da, and 6828.80 Da, respectively. NT-I consisted of 62 amino acid residues, and the other two consisted of 61 amino acid residues, including 8 cysteines. After hydrolysis by endoproteinase Glu-C, their primary sequences were determined. A test of their activities demonstrated that they effectively inhibited muscle contractions induced by electric stimulation. Furthermore, the extent of inhibition caused by NT-II and NT-III was less than that of NT-I. The IC(50)s were 0.04 mug/ml, 0.20 mug/ml, and 0.23 mug/ml for NT-I, NT-II, and NT-III, respectively. Compared with NT-II and NT-III, the higher activity of NT-I may be a result of the amino acid residue substitution Ile36 to Arg36.

MicroRNAs and other small RNAs enriched in the Arabidopsis RNA-dependent RNA polymerase-2 mutant.

The Arabidopsis genome contains a highly complex and abundant population of small RNAs, and many of the endogenous siRNAs are dependent on RNA-Dependent RNA Polymerase 2 (RDR2) for their biogenesis. By analyzing an rdr2 loss-of-function mutant using two different parallel sequencing technologies, MPSS and 454, we characterized the complement of miRNAs expressed in Arabidopsis inflorescence to considerable depth. Nearly all known miRNAs were enriched in this mutant and we identified 13 new miRNAs, all of which were relatively low abundance and constitute new families. Trans-acting siRNAs (ta-siRNAs) were even more highly enriched. Computational and gel blot analyses suggested that the minimal number of miRNAs in Arabidopsis is approximately 155. The size profile of small RNAs in rdr2 reflected enrichment of 21-nt miRNAs and other classes of siRNAs like ta-siRNAs, and a significant reduction in 24-nt heterochromatic siRNAs. Other classes of small RNAs were found to be RDR2-independent, particularly those derived from long inverted repeats and a subset of tandem repeats. The small RNA populations in other Arabidopsis small RNA biogenesis mutants were also examined; a dcl2/3/4 triple mutant showed a similar pattern to rdr2, whereas dcl1-7 and rdr6 showed reductions in miRNAs and ta-siRNAs consistent with their activities in the biogenesis of these types of small RNAs. Deep sequencing of mutants provides a genetic approach for the dissection and characterization of diverse small RNA populations and the identification of low abundance miRNAs.

Role of RNA polymerase IV in plant small RNA metabolism.

In addition to the three RNA polymerases (RNAP I-III) shared by all eukaryotic organisms, plant genomes encode a fourth RNAP (RNAP IV) that appears to be specialized in the production of siRNAs. Available data support a model in which dsRNAs are generated by RNAP IV and RNA-dependent RNAP 2 (RDR2) and processed by DICER (DCL) enzymes into 21- to 24-nt siRNAs, which are associated with different ARGONAUTE (AGO) proteins for transcriptional or posttranscriptional gene silencing. However, it is not yet clear what fraction of genomic siRNA production is RNAP IV-dependent, and to what extent these siRNAs are preferentially processed by certain DCL(s) or associated with specific AGOs for distinct downstream functions. To address these questions on a genome-wide scale, we sequenced approximately 335,000 siRNAs from wild-type and RNAP IV mutant Arabidopsis plants by using 454 technology. The results show that RNAP IV is required for the production of >90% of all siRNAs, which are faithfully produced from a discrete set of genomic loci. Comparisons of these siRNAs with those accumulated in rdr2 and dcl2 dcl3 dcl4 and those associated with AGO1 and AGO4 provide important information regarding the processing, channeling, and functions of plant siRNAs. We also describe a class of RNAP IV-independent siRNAs produced from endogenous single-stranded hairpin RNA precursors.

In vitro construction of a recombinant human embryonic brain-derived neurotrophin-4 gene and pEGFP-N1 vector

BACKGROUND: Neurotrophin-4 (NT-4) can promote neuronal growth, development, differentiation, maturation, and survival. NT-4 can also improve recovery and regeneration of injured neurons, but cannot pass through the blood-brain barrier, which limits its ac

HSPC117 deficiency in cloned embryos causes placental abnormality and fetal death

Somatic cell nuclear transfer (SCNT) has been successfully used in many species to produce live cloned offspring, albeit with low efficiency. The low frequency of successful development has usually been ascribed to incomplete or inappropriate reprogramming of the transferred nuclear genome. Elucidating the genetic differences between normal fertilized and cloned embryos is key to understand the low efficiency of SCNT. Here, we show that expression of HSPC117, which encodes a hypothetical protein of unknown function, was absent or very low in cloned mouse blastocysts. To investigate the role of HSPC117 in embryo development, we knocked-down this gene in normal fertilized embryos using RNA interference. We assessed the post-implantation survival of HSPC117 knock-down embryos at 3 stages: E9 (prior to placenta formation); E12 (after the placenta was fully functional) and E19 (post-natal). Our results show that, although siRNA-treated in vivo fertilized/produced (IVP) embryos could develop to the blastocyst stage and implanted without any difference from control embryos, the knock-down embryos showed substantial fetal death, accompanied by placental blood clotting, at E12. Furthermore, comparison of HSPC117 expression in placentas of nuclear transfer (NT), intracytoplasmic sperm injection (ICSI) and IVP embryos confirmed that HSPC117 deficiency correlates well with failures in embryo development: all NT embryos with a fetus, as well as IVP and ICSI embryos, had normal placental HSPC117 expression while those NT embryos showing reduced or no expression of HSPC117 failed to form a fetus. In conclusion, we show that HSPC117 is an important gene for post-implantation development of embryos, and that HSPC117 deficiency leads to fetal abnormalities after implantation, especially following placental formation. We suggest that defects in HSPC117 expression may be an important contributing factor to loss of cloned NT embryos in vivo. (C) 2010 Elsevier Inc. All rights reserved.

中国株丙型肝炎病毒(HCV)感染猕猴后5^NTR-C区基因组的cDNA序列分析

从2份受丙型肝炎病毒(HCV)感染的献血员血清(CX1、CX2)、第一代感染HCV猕猴血清(CX3)、第二代感染HCV猕猴血清(CX4)中提取RNA, 用自行设计的HCV 5^非编码区和核心区C5^NTR-C区引物进行逆转录PCR, 经扩增克隆并序列分析, 结果显示: CX1 cDNA全长779bp, CX2 cDNA 778bp, CX3 cDNA 776bp, CX4 cDNA 777bp。CX1株和CX4株均在5^NTR nt-216有一C的插入, CX3和CX4区nt385-387处的3个碱基缺失; CX1株与CX2、CX3、CX4比较同源性分别为98.07%、96.15%、95.25%; CX2与CX3、CX4的同源性分别为96.28%、95.76%; CX3与CX4的同源性为97.56%。

Photo thermal induced effects on testes and pituitary gonadotropic cells during resting phase of reproductive cycle in a murrel, Channa punctatus (Bloch)

Effects of various combinations of photoperiod and temperature (NL-NT, LD 15:9-28°C, NL-28°C and LD 15:9 NT) were studied on testicular activity and pituitary gonadotropic cells in Channa punctatus during resting phase of reproductive cycle. Long photoperiod (LD 15:9-28°C) and warm temperature (NL-28°C) regimes were found to be more effective for testicular maturation and secretory activity of gonadotropic cells suggesting testicular maturation via brain-pituitary-testicular axis.

基因工程化分泌神经营养因子一3的鼠胚神经干细胞实验研究

：探索以Lentivirus为载体，构建同时表达绿色荧光蛋白(GFP)和神经营养因子一3(NT一3)的基因工程化鼠胚神经于细胞(NSC)的可行性。方法：体外分离培养鼠胚NSC，用同时携带NT一3和GFP的lentivirus转染构建工程化NSC；用荧光显微镜、鼠胚背根神经结培养(Dorsal Root Ganglion，DRG)、Westem blot等方法检测基因工程NSC 的转基因表达。结果：荧光显微镜观察到几乎100％的工程化NSC表达GFP：DRG培养和Westem blot检测到基因工程化NSC能高效分泌NT一3蛋白。结论：以IJentivirus为载体，构建同时携带并稳定表达GFP和N‘r_3的基因工程化鼠胚NSC是可行的，可为脊髓损伤基础研究提供有价值的细胞资源。