载脂蛋白多基因家族分子进化的研究

与脂质运输有关的载脂蛋白基因构成一个复杂的多基因家族。为探讨这种演化时间长的基因家族的进化规律,本文首先建立了一种在非均衡进化速率条件下计算系统发生树中任意分支长度的简易方法,并可在此基础上算出无根分支系统树中分歧年代的期望值。进一步对本文科１０个种属共２６种载脂蛋白的系统演作作了实际分析,结果提示：①ＡｐｏＡ－Ｉ＇ＡｐｏＡ－ＩＶ,ＡｐｏＥ及ＡｐｏＡ－ＩＩ的共同祖先可能在奥陶纪水生脊椎动物中就已存     

辐射增敏剂增敏活性的分子连接性研究

计算４２个辐射增敏剂的各阶分子连接性指数ｍＸｔ及△ｍＸｔ,并对其中３８个非对称性化合物的分子连接性指数与其增敏活性进行定量构效关系（ＱｕａｎｔｉｔａｔｉｒｅＳｔｒｕｃｔｕｒｅＡｃｔｉｖｉｔｙＲｅｌａｔｉｏｎｓｈｉｐ,ＱＳＡＲ）的研究,得到相关方程。并分析了影响增敏活性的１ｇＰ、ＥＳ及σ在一定程度上都可通过分子连接性指数表达出来。对这些增敏剂进行分子对称性的研究,发现对称性会降低分子的极性,进而降低其增敏活性。另外,还发现在这些增敏剂中存在亚类现象,并对各亚类的反应机理进行了探讨。     

转基因微生物生态学及大田释放风险评价研究

向环境中释放转基因微生物可能会带来一系列的安全问题．在大面积释放之前必须对转基因微生物在环境中发生基因转移的潜力、存活能力、扩散能力及对生态系统的潜在影响等进行生态学研究和风险评价,同时还要探索有效的检测方法和风险评价策略．该研究有助于分子生态学的发展和生物技术的安全应用,具有重要的理论和实践意义．     

Characterization of the major proteins of bovine seminal fluid by two-dimensional polyacrylamide gel electrophoresis

Recently, we demonstrated that the major proteins from bovine seminal plasma BSP-A1, -A2, -A3 and -30-kDa (collectively called BSP proteins) specifically interact with choline phospholipids. These proteins coat the surface of the spermatozoa after ejaculation and are believed to play an important role in membrane modifications occurring during capacitation. In this study we determined the isoelectric point (pl) and analysed the molecular heterogeneity of BSP proteins. Total protein from bovine seminal plasma (CBSP) and purified BSP proteins were iodinated using chloramine T. Samples were reduced, denatured, separated by two-dimensional polyacrylamide gel electrophoresis (2D-PAGE), and visualized by autoradiography. Analysis of CBSP proteins demonstrated the presence of polypeptides migrating in the pH range of 3.5–7.8 and at molecular weights (Mr) between 6 and 100 kDa. Many isoforms of each BSP protein were found when purified iodinated proteins were analysed by 2D-PAGE. BSP-A1 was found at a Mr of 16.5 kDa and in the range of pl of 4.7–5.0; BSP-A2 at 16 kDa and at a pl of 4.9–5.2; BSP-A3 at 15 kDa and at a pl of 4.8–5.2, and BSP-30-kDa at 28 kDa and at a pl of 3.9–4.6. Similar results were obtained with immunolocalization of BSP proteins after Western blot using specific antibodies. The treatment of purified iodinated BSP proteins with neuraminidase increased the pl of BSP-30-kDa to 4.8–5.0 and decreased its Mr to 25 kDa, but no change was observed for BSP-A1, -A2 and -A3. The treatment of BSP proteins with sulfatase or acid phosphatase modified neither their Mr nor their pl. Furthermore, when CBSP proteins were separated in 2D-PAGE and the gels stained for glycoproteins with dansyl hydrazine, BSP proteins were among the major glycoproteins found in the bovine seminal plasma. In conclusion, BSP proteins are acidic and have several isoforms. Furthermore, the heterogeneity of BSP-30-kDa is mainly due to its sialic acid content. © 1994 Wiley-Liss, Inc.     

Comparison between the complete mtDNA sequences of the blue and the fin whale,two species that can hybridize in nature

The sequence of the mitochondrial DNA (mtDNA) molecule of the blue whale (Balaenoptera musculus) was determined. The molecule is 16,402 by long and its organization conforms with that of other eutherian mammals. The molecule was compared with the mtDNA of the congeneric fin whale (B. physalus). It was recently documented that the two species can hybridize and that male offspring are infertile whereas female offspring may be fertile. The present comparison made it possible to determine the degree of mtDNA difference that occurs between two species that are not completely separated by hybridization incompatibility. The difference between the complete mtDNA sequences was 7.4%. Lengths of peptide coding genes were the same in both species. Except for a small portion of the control region, disruption in alignment was usually limited to insertion/deletion of a single nucleotide. Nucleotide differences between peptide coding genes ranged from 7.1 to 10.5%, and difference at the inferred amino acid level was 0.0–7.9%. In the rRNA genes the mean transition difference was 3.8%. This figure is similar in degree to the difference (3.4%) between the 12S rRNA gene of humans and the chimpanzee. The mtDNA differences between the two whale species, involving both peptide coding and rRNA genes, suggest an evolutionary separation of 5 million years. Although hybridization between more distantly related mammalian species may not be excluded, it is probable that the blue and fin whales are nearly as different in their mtDNA sequences as hybridizing mammal species may be. Correspondence to: Ú. Árnason     

Time and biosequences

In this paper we discuss and demonstrate the importance of several factors relative to the relationship between time and evolution of biosequences. In both quantitative and qualitative measurements of the genetic distances, the compositional constraints of the nucleotide sequences play a very important role. We demonstrate that when homologous sequences significantly differ in base composition we get erratic branching order and/or wrong evaluation of the evolutionary rates. We must consider that every gene may have a different evolutionary dynamic along its sequence, generally linked to its functional constraints; this too can seriously affect its clocklike behavior. We report some cases showing how these factors can affect the quantitative measurements of the genetic distances of biosequences. Presented at the NATO Advanced Research Workshop onGenome Organization and Evolution, Spetsai, Greece, 16–22 September 1992     

Restriction fragment length polymorphism and molecular taxonomy in Vitis vinifera L.

Forty-six accessions of grapevine (V. vinifera L.) were compared by restriction fragment length polmorphism (RFLP) analysis, and 111 informative or unique restriction fragments were found that revealed an important level of polymorphism. RFLP patterns were compared in two ways: by calculating electrophoretic similarity degree values further analyzed by principal component analysis and by studying the distribution of rare restriction fragments. Six taxonomic groups could be defined, which partially confirmed relationships derived from ampelographical data. Our data support the existence of ecogeographical groups.     

The second phantom aquatic leaf beetle in Japan: Macroplea mutica rediscovery in the wetlands (Coleoptera: Chrysomelidae)

Wetland biodiversity is currently declining on a global scale. Wetland biodiversity understanding is critical for determining the wetlands' conservation value. In this study, Macroplea Samouelle, 1819 (Coleoptera: Chrysomelidae) was discovered in Aomori Prefecture, Honshu Island, Japan. Only two Macroplea species have been recorded in Japan, M. japana (Jacoby, 1885) and M. mutica (Fabricius, 1792). Macroplea japana had been unrecorded for 60 years before being rediscovered in Honshu Island in 2022, and a single adult M. mutica female was discovered in Hokkaido Prefecture in 2003. The discovered individuals were concluded to be M. mutica based on morphological and molecular analyses. Although morphological differences were observed with the Eurasian M. mutica individuals, the male genitalia was nearly identical to M. mutica. For the molecular phylogenetic analysis based on COI and 28S sequences, Macroplea individuals in Japan were clustered with M. mutica on the Eurasian Continent. This is the first record of this species on Honshu Island (and the second in Japan), as well as the first record of adult males. This species would require conservation policies and additional distributional surveys.     

Integrating experimental data with molecular simulations to investigate RNA structural dynamics

Conformational dynamics is crucial for ribonucleic acid (RNA) function. Techniques such as nuclear magnetic resonance, cryo-electron microscopy, small- and wide-angle X-ray scattering, chemical probing, single-molecule Förster resonance energy transfer, or even thermal or mechanical denaturation experiments probe RNA dynamics at different time and space resolutions. Their combination with accurate atomistic molecular dynamics (MD) simulations paves the way for quantitative and detailed studies of RNA dynamics. First, experiments provide a quantitative validation tool for MD simulations. Second, available data can be used to refine simulated structural ensembles to match experiments. Finally, comparison with experiments allows for improving MD force fields that are transferable to new systems for which data is not available. Here we review the recent literature and provide our perspective on this field.     

The progress of DNA analyzing techniques and its impact on plant molecular systematics

Recent advances in manipulating nucleic acids have opened a new research field called plant molecular systematics. This short review provides an overview of molecular techniques which have been used in the analysis of DNA molecules for the study of plant systematics, with a special emphasis on PCR. The early application of DNA analysis, DNA/DNA hybridization, has not become popular with plant systematists, because of several disadvantages inherent in the method. The survey of restriction fragment length polymorphisms (RFLPs), on the contrary, has become one of the preferred methods used by plant molecular systematists, since the method is relatively easy to perform. Although unambiguous data can be obtained by both long-range restriction mapping and nucleotide sequencing, these approaches may have limited use in plant molecular systematics because of their laborious experimental procedures relying on conventional molecular cloning techniques. To date, PCR based analyses of the DNA molecule seem to be the most suitable experimental approach for plant molecular systematics. Several advantages of the method have changed both the quality and quantity of the DNA data. Further application of PCR to plant molecular systematics will open up a new era in the field. The present paper is based on the contribution which was read in a symposium entitled “Organellar DNA Variations in Higher Plants and their Taxonomic Significance”, at the 50th Annual Meeting of the Botanical Society of Japan in Shizuoka on October 2, 1990, under the auspices of the Japan Society of Plant Taxonomists.