Cloning and expression profiling of small RNAs expressed in the mouse ovary

Small noncoding RNAs have been suggested to play important roles in the regulation of gene expression across all species from plants to humans. To identify small RNAs expressed by the ovary, we generated mouse ovarian small RNA complementary DNA (srcDNA) libraries and sequenced 800 srcDNA clones. We identified 236 small RNAs including 122 microRNAs (miRNAs), 79 piwi-interacting RNAs (piRNAs), and 35 small nucleolar RNAs (snoRNAs). Among these small RNAs, 15 miRNAs, 74 piRNAs, and 21 snoRNAs are novel. Approximately 70% of the ovarian piRNAs are encoded by multicopy genes located within the repetitive regions, resembling previously identified repeat-associated small interference RNAs (rasiRNAs), whereas the remaining approximately 30% of piRNA genes are located in nonrepetitive regions of the genome with characteristics similar to the majority of piRNAs originally cloned from the testis. Since these two types of piRNAs display different structural features, we categorized them into two classes: repeat-associated piRNAs (rapiRNAs, equivalent of the rasiRNAs) and non-repeat-associated piRNAs (napiRNAs). Expression profiling analyses revealed that ovarian miRNAs were either ubiquitously expressed in multiple tissues or preferentially expressed in a few tissues including the ovary. Ovaries appear to express more rapiRNAs than napiRNAs, and sequence analyses support that both may be generated through the "ping-pong" mechanism. Unique expression and structural features of these ovarian small noncoding RNAs suggest that they may play important roles in the control of folliculogenesis and female fertility.     

Cytoplasm-localized SIRT1 enhances apoptosis

In general, SIRT1 is localized in nuclei. Here, we showed that endogenous and exogenous SIRT1 were both able to partially localize in cytoplasm in certain cell lines, and cytoplasm-localized SIRT1 was associated with apoptosis and led to increased sensitivity to apoptosis. Furthermore, we demonstrated that translocation of nucleus-localized SIRT1 from nuclei to cytoplasm was the main pathway leading to localization of SIRT1 in cytoplasm. In HeLa cells, wild type SIRT1 was completely localized in nuclei. By truncation of two predicted nuclear localization signals or fusion with an exogenous nuclear export signal, SIRT1 was partially localized in cytoplasm of HeLa cells and resulted in increased sensitivity to apoptosis. The apoptosis enhanced by cytoplasm-localized SIRT1 was independent of its deacetylase activity, but dependent on caspases. SIRT1 was distributed in cytoplasm at metaphase during mitosis, and overexpression of SIRT1 significantly augmented apoptosis for cells at metaphase. In summary, we found SIRT1 is able to localize in cytoplasm, and cytoplasm-localized SIRT1 enhances apoptosis.     

后倾座椅与GZ-2抗荷服综合抗荷性能测定

目的 :探讨后倾座椅与GZ 2抗荷服的综合抗荷性能。方法 :在离心机上 ( +Gz增长率为 3G/s)先测出 6名受试者采用 13°座椅时的基础 +Gz耐力 ,然后测定受试者采用 13°座椅、并穿GZ 2抗荷服充气时的 +Gz耐力 ,再测定受试者采用 45°后倾座椅、并穿GZ 2抗荷服充气时的 +Gz耐力 ,其与基础 +Gz耐力之差 ,即为 45°座椅与GZ 2抗荷服的综合抗荷性能。结果 :受试者采用 13°座椅、穿GZ 2时的抗荷性能为 3 .0 6G ,采用 45°座椅、穿GZ 2时的抗荷性能为 4.13G ,抗荷性能比前者高出 1.0 6G。结论 :后倾座椅 (椅背角为 45°)可大幅度提高人体 +Gz耐力     

Synthesis and biological evaluation of 3'-carboranyl thymidine analogues

Boron neutron capture therapy (BNCT) is a chemoradio-therapeutic method for the treatment of cancer. It depends on the selective targeting of tumor cells by boron-containing compounds. One category of BNCT agents with potential to selectively target tumor cells may be thymidine derivatives substituted at the 3'-position with appropriate boron moieties. Thus, several thymidine analogues were synthesized with a carborane cluster bound to the 3'-position either through an ether or a carbon linkage. The latter are the first reported carborane-containing nucleosides in which the carboranyl entity is directly linked to the carbohydrate portion of the nucleoside by a carbon-carbon bond. Low but significant phosphorylation rates in the range of 0.18% that of thymidine were observed for the carbon-linked 3'-carboranyl thymidine analogues in phosphoryl transfer assays using recombinant preparations of thymidine kinases 1 (TK1) and thymidine kinases 2 (TK2). Some of the ether-linked 3'-carboranyl thymidine analogues appeared to be slightly unstable under acidic as well as phosphoryl transfer assay conditions and were, if at all, poor substrates for TK1.     

WAVE2 deficiency reveals distinct roles in embryogenesis and Rac-mediated actin-based motility

The Wiskott-Aldrich syndrome related protein WAVE2 is implicated in the regulation of actin-cytoskeletal reorganization downstream of the small Rho GTPase, Rac. We inactivated the WAVE2 gene by gene-targeted mutation to examine its role in murine development and in actin assembly. WAVE2-deficient embryos survived until approximately embryonic day 12.5 and displayed growth retardation and certain morphological defects, including malformations of the ventricles in the developing brain. WAVE2-deficient embryonic stem cells displayed normal proliferation, whereas WAVE2-deficient embryonic fibroblasts exhibited severe growth defects, as well as defective cell motility in response to PDGF, lamellipodium formation and Rac-mediated actin polymerization. These results imply a non-redundant role for WAVE2 in murine embryogenesis and a critical role for WAVE2 in actin-based processes downstream of Rac that are essential for cell movement.     

IFN-gamma-producing gamma delta T cells help control murine West Nile virus infection

West Nile (WN) virus causes fatal meningoencephalitis in laboratory mice, thereby partially mimicking human disease. Using this model, we have demonstrated that mice deficient in gammadelta T cells are more susceptible to WN virus infection. TCRdelta(-/-) mice have elevated viral loads and greater dissemination of the pathogen to the CNS. In wild-type mice, gammadelta T cells expanded significantly during WN virus infection, produced IFN-gamma in ex vivo assays, and enhanced perforin expression by splenic T cells. Adoptive transfer of gammadelta T cells to TCRdelta(-/-) mice reduced the susceptibility of these mice to WN virus, and this effect was primarily due to IFN-gamma-producing gammadelta T cells. These data demonstrate a distinct role for gammadelta T cells in the control of and prevention of mortality from murine WN virus infection.     

DISCOVERY OF TWO MID-TERTIARY MAMMALIAN FAUNAS FROM HAIYUAN, NINGXIA, CHINA

Inl988-199otheRegionalGeologicalSurveyTeamoftheGeologicalBureauofNingxia(RGSN)foundsomefossilmammalsinthelowerpartoftheHo11g1iugouFormationandtheupperpartoftheOligocene.Inl992ajointteamoflnstituteofVertebratePaleontologyandPaleoanthropo1ogy,AcademiaSinica(IVPP),andtheRGSNwenttoHaiyuailCountyandcollectedmorefossilmamma1sfromtheYuanjia-wowoareausi11gascreen-washingmethodThemammalfaunafromthelowerpartoftheHongliugouFormationiscomposedofAprotodonsp.,Indricotheriidaeindet.,Rhinoceroti…     

Dynamics of gene introgression in the African malaria vector Anopheles gambiae

Anopheles gambiae is a major malaria vector in Africa and a popular model species for a variety of ecological, evolutionary, and genetic studies on vector control. Genetic manipulation of mosquito vectorial capacity is a promising new weapon for the control of malaria. However, the release of exotic transgenic mosquitoes will bring in novel alleles in addition to the parasite-inhibiting genes, which may have unknown effects on the local population. Therefore, it is necessary to develop methodologies that can be used to evaluate the spread rate of introduced genes in A. gambiae. In this study, the effects and dynamics of genetic introgression between two geographically distinct A. gambiae populations from western Kenya (Mbita) and eastern Tanzania (Ifakara) were investigated with amplified fragment length polymorphisms (AFLPs) and microsatellite markers. Microsatellites and polymorphic cDNA markers revealed a large genetic differentiation between the two populations (average F(ST) = 0.093, P < 0.001). When the two strains were crossed in random mating between the two populations, significant differences in the rate of genetic introgression were found in the mixed populations. Allele frequencies of 18 AFLP markers (64.3%) for Mbita and of 26 markers (92.9%) for Ifakara varied significantly from F5 to F20. This study provides basic information on how a mosquito release program would alter the genetic makeup of natural populations, which is critical for pilot field testing and ecological risk evaluation of transgenic mosquitoes.