编码区和非编码区SSR标记对水稻类群的比较研究

设计14对水稻编码区SSR引物和选取已公布的非编码区SSR引物12对、编码区SSR引物3对,采用SSR技术,对29个标记在60个水稻材料中的多态性进行分析。结果表明,编码区SSR标记平均检测到3.59个多态性位点,多态信息量PIC(polymorphism information conten)在0.032～P0.853之间,平均值为0.447;非编码区SSR标记平均检测到3.92个多态性位点,PIC在0.063～P0.795之间,平均值为0.521。聚类分析显示,非编码区SSR标记能更加精确地区分来自不同地区的水稻类群,编码区SSR标记也具有良好的多态性,同样可以用于分析水稻的亲缘关系。     

Mayr on the Polynesian Region

[Borders and Subdivisions of the Polynesian Region, as based on our Knowledge of the Distribution of Birds, pp. 191–195. The Origin and History of the Bird fauna of Polynesia, pp. 197–216. By Ernst Mayr. Proc. Sixth Pacific Science Congress, held at Berkeley, Wis., in July and August 1939, vol. iv.]     

The Greater Cape Floristic Region

Aim The Cape Floristic Region (CFR) (Cape Floristic Kingdom) is currently narrowly delimited to include only the relatively mesic Cape fold mountains and adjacent intermontane valleys and coastal plains. We evaluate the floristic support for expanding the delimitation to include the whole winter‐rainfall area (arid and mesic climates) into a Greater CFR. Location Southern Africa, particularly the south‐western tip. Methods The initial divisive hierarchical classification analysis twinspan used the presence/absence of vascular plant genera to obtain major floristic groupings in southern Africa. For the more detailed analyses, we scored the flora as present/absent within a set of centres, among which the floristic relationships were investigated (agglomerative methods, upgma and minimum spanning trees). These analyses were conducted with species, genera and families separately. The centres were grouped into five regions. The species richness and endemism was calculated for the centres, regions and combination of regions. The dominant floristic components of each region were sought by calculating the percentage contribution of each family to the flora. Results The divisive method showed that the winter‐rainfall areas are floristically distinct from the rest of southern Africa. The species‐ and generic‐level analyses revealed five regions: CFR, Karoo Region, Hantam‐Tanqua‐Roggeveld Region, Namaqualand Region and Namib‐Desert Region. The CFR has the highest endemism and richness. However, the combination of the CFR, the Hantam‐Tanqua‐Roggeveld Region and the Namaqualand Region results in a higher total endemism. Combined, these three regions almost match the region delimited by the twinspan analysis, and together constitute the Greater CFR. Main conclusions The CFR constitutes a valid floristic region. This is evident from the endemism and the distinctive composition of the flora. However, the total endemism is higher for the whole winter‐rainfall area, and this supports the recognition of the larger unit. If floristic regions are to be delimited only on endemism, then the Greater CFR is to be preferred. If floristic regions are delimited on the composition of their floras at family level, then the support for such a grouping is weaker.     

丙型肝炎病毒Core与NS3基因的不同融合方式及其表达

丙型肝炎病毒(简称HCV)是危害人类健康的传染性疾病,预防该病的传播主要借助于HCV血清学诊断来筛选献血员和检测临床标本.从国内外已分离到的HCV株得知,HCV核心蛋白(Core)和非结构蛋白NS3含有较强的优势抗原表位,其相应的抗体出现早,阳性率高,已成为目前第二、第三代HCV免疫诊断试剂的重要成份[1,2].通常Core蛋白和NS3蛋白分别用基因工程方法表达,然后作为固定化抗原,检测人体内HCV的抗体.我们对Core和NS3的两种不同组合方式及其表达的研究,对于发展新的HCV诊断试剂很有帮助,现将结果报道如下.     

Conserved Region of Mammalian Retrovirus RNA

The viral RNAs of various mammalian retroviruses contain highly conserved sequences close to their 3' ends. This was demonstrated by interviral molecular hybridization between fractionated viral complementary DNA (cDNA) and RNA. cDNA near the 3' end (cDNA(3')) from a rat virus (RPL strain) was fractionated by size and mixed with mouse virus RNA (Rauscher leukemia virus). No hybridization occurred with total cDNA (cDNA(total)), in agreement with previous results, but a cross-reacting sequence was found with the fractionated cDNA(3'). The sequences between 50 to 400 nucleotides from the 3' terminus of heteropolymeric RNA were most hybridizable. The rat viral cDNA(3') hybridized with mouse virus RNA more extensively than with RNA of remotely related retroviruses. The related viral sequence of the rodent viruses (mouse and rat) showed as much divergence in heteroduplex thermal denaturation profiles as did the unique sequence DNA of these two rodents. This suggests that over a period of time, rodent viruses have preserved a sequence with changes correlated to phylogenetic distance of hosts. The cross-reacting sequence of replication-competent retroviruses was conserved even in the genome of the replication-defective sarcoma virus and was also located in these genomes near the 3' end of 30S RNA. A fraction of RD114 cDNA(3'), corresponding to the conserved region, cross-hybridized extensively with RNA of a baboon endogenous virus (M7). Fractions of similar size prepared from cDNA(3') of MPMV, a primate type D virus, hybridized with M7 RNA to a lesser extent. Hybridization was not observed between Mason-Pfizer monkey virus and M7 if total cDNA's were incubated with viral RNAs. The degree of cross-reaction of the shared sequence appeared to be influenced by viral ancestral relatedness and host cell phylogenetic relationships. Thus, the strikingly high extent of cross-reaction at the conserved region between rodent viruses and simian sarcoma virus and between baboon virus and RD114 virus may reflect ancestral relatedness of the viruses. Slight cross-reaction at the site between type B and C viruses of rodents (mouse mammary tumor virus and RPL virus, 58-2T) or type C and D viruses of primates (M7, RD114, and Mason-Pfizer monkey virus) may have arisen at the conserved region through a mechanism that depends more on the phylogenetic relatedness of the host cells than on the viral type or origin. Determining the sequence of the conserved region may help elucidate this mechanism. The conserved sequences in retroviruses described here may be an important functional unit for the life cycle of many retroviruses.     

丙型肝炎病毒Core与NS3基因的不同融合方式及其表达

丙型肝炎病毒(简称ＨＣＶ)是危害人类健康的传染性疾病,预防该病的传播主要借助于ＨＣＶ血清学诊断来筛选献血员和检测临床标本。从国内外已分离到的ＨＣＶ株得知,ＨＣＶ核心蛋白(Ｃｏｒｅ)和非结构蛋白ＮＳ3含有较强的优势抗原表位,其相应的抗体出现早,阳性率高,已成为目前第二、第三代ＨＣＶ免疫诊断试剂的重要成份[1,2]。通常Ｃｏｒｅ蛋白和ＮＳ3蛋白分别用基因工程方法表达,然后作为固定化抗原,检测人体内ＨＣＶ的抗体。我们对Ｃｏｒｅ和ＮＳ3的两种不同组合方式及其表达的研究,对于发展新的ＨＣＶ诊断试剂很有帮助,现将结果报道如下。1…     

Pluripotenzerscheinungen in der Region der Rachendachhypophyse

Ohne ZusammenfassungAnm. Die Arbeit wurde durch die Bereitstellung von Mitteln der Notgemeinschaft Deutscher Wissenschaft gefördert.     

River-reef connectivity in the Meso-American Region

The accumulation and seasonal impact of riverine discharge on coral reefs of the Meso-American Region (MAR) were estimated using a numerical simulation of river runoff dispersion. River-reef connectivity, or source-sink dynamics of terrestrial runoff was further assessed from more than 400 watersheds of the region onto discrete coral reef areas. Using land use for 2003 and 2004 in the MAR, this work builds upon a Regional Ocean Modeling System simulation of the MAR validated by ocean color satellite data, and on the monthly river nutrient and sediment load and discharge provided by the World Resources Institute using the N-SPECT model. Analysis of the variability of simulated runoff transport to the reefs showed that reefs of the Mesoamerican Barrier Reef System (MBRS) were mostly impacted from June to September, following the peak time of river discharge. At that time, the coastal and oceanic circulations contribute quickly to expel the runoff from the MBRS. High runoff concentration waters leaving the eastern coast of Honduras during the months of October to December return to the southwestern MAR in March as they are entrained in a cyclonic gyre. Coral reefs of the MAR are thus impacted twice, first from the coastal side with runoff of local origin and later from the oceanic side with runoff from mixed origin. High probability of connectivity between rivers and remote reefs is established as this study revealed that river runoff from the north shore of Honduras has a wide-spread impact on most of the coral reefs of southern Belize, while watersheds on the Gulf of Honduras are mostly connected to coral reefs in the northern shore of Honduras. Although the level of remote influence (or runoff concentration reaching the reef) is lower than the local, the cumulative effect of numerous remote river-reef connections remains significant. Communicated by Biology Editor Michael Lesser     

Marine Biodiversity in the Australian Region

The entire Australian marine jurisdictional area, including offshore and sub-Antarctic islands, is considered in this paper. Most records, however, come from the Exclusive Economic Zone (EEZ) around the continent of Australia itself. The counts of species have been obtained from four primary databases (the Australian Faunal Directory, Codes for Australian Aquatic Biota, Online Zoological Collections of Australian Museums, and the Australian node of the Ocean Biogeographic Information System), but even these are an underestimate of described species. In addition, some partially completed databases for particular taxonomic groups, and specialized databases (for introduced and threatened species) have been used. Experts also provided estimates of the number of known species not yet in the major databases. For only some groups could we obtain an (expert opinion) estimate of undiscovered species. The databases provide patchy information about endemism, levels of threat, and introductions. We conclude that there are about 33,000 marine species (mainly animals) in the major databases, of which 130 are introduced, 58 listed as threatened and an unknown percentage endemic. An estimated 17,000 more named species are either known from the Australian EEZ but not in the present databases, or potentially occur there. It is crudely estimated that there may be as many as 250,000 species (known and yet to be discovered) in the Australian EEZ. For 17 higher taxa, there is sufficient detail for subdivision by Large Marine Domains, for comparison with other National and Regional Implementation Committees of the Census of Marine Life. Taxonomic expertise in Australia is unevenly distributed across taxa, and declining. Comments are given briefly on biodiversity management measures in Australia, including but not limited to marine protected areas.     

A Nucleotide State-sensing Region on Actin

The nucleotide state of actin (ATP, ADP-P_i, or ADP) is known to impact its interactions with other actin molecules upon polymerization as well as with multiple actin binding proteins both in the monomeric and filamentous states of actin. Recently, molecular dynamics simulations predicted that a sequence located at the interface of subdomains 1 and 3 (W-loop; residues 165–172) changes from an unstructured loop to a β-turn conformation upon ATP hydrolysis (Zheng, X., Diraviyam, K., and Sept, D. (2007) Biophys. J. 93, 1277–1283). This region participates directly in the binding to other subunits in F-actin as well as to cofilin, profilin, and WH2 domain proteins and, therefore, could contribute to the nucleotide sensitivity of these interactions. The present study demonstrates a reciprocal communication between the W-loop region and the nucleotide binding cleft on actin. Point mutagenesis of residues 167, 169, and 170 and their site-specific labeling significantly affect the nucleotide release from the cleft region, whereas the ATP/ADP switch alters the fluorescence of probes located in the W-loop. In the ADP-P_i state, the W-loop adopts a conformation similar to that in the ATP state but different from the ADP state. Binding of latrunculin A to the nucleotide cleft favors the ATP-like conformation of the W-loop, whereas ADP-ribosylation of Arg-177 forces the W-loop into a conformation distinct from those in the ADP and ATP-states. Overall, our experimental data suggest that the W-loop of actin is a nucleotide sensor, which may contribute to the nucleotide state-dependent changes in F-actin and nucleotide state-modulated interactions of both G- and F-actin with actin-binding proteins.