Distribution of post-weaning Antarctic fur seal Arctocephalus gazella pups at South Georgia

Potentially some of the biggest gaps in our knowledge about the ecology of Antarctic fur seals (Arctocephalus gazella) relate to juvenile animals. We investigated the at-sea distribution of five male and five female fur seal pups post-weaning. The study was carried out at Bird Island, South Georgia during two successive winters using satellite-linked platform transmitter terminals (PTTs). Our results are analysed in relation to pup sex and the physical environment and productivity of those 2 years, as well as in the context of our present knowledge of where post-breeding females and males forage. The available physical and biological data during both of the winters of this study suggest that both years were not unusual. We report marked differences between the sexes with male pups foraging significantly further away from land and their birth site than do females. The pups foraged in areas to the East of Bird Island seldom reported as foraging areas for the adult population. Also as winter progressed they showed a more oceanic distribution leaving the continental shelf, possibly to exploit a different prey source that was more readily available in the upper water column.     

Drosophila importin alpha1 performs paralog-specific functions essential for gametogenesis

Importin alpha's mediate nuclear transport by linking nuclear localization signal (NLS)-containing proteins to importin beta1. Animal genomes encode three conserved groups of importin alpha's, alpha1's, alpha2's, and alpha3's, each of which are competent to bind classical NLS sequences. Using Drosophila melanogaster we describe the isolation and phenotypic characterization of the first animal importin alpha1 mutant. Animal alpha1's are more similar to ancestral plant and fungal alpha1-like genes than to animal alpha2 and alpha3 genes. Male and female importin alpha1 (Dalpha1) null flies developed normally to adulthood (with a minor wing defect) but were sterile with defects in gametogenesis. The Dalpha1 mutant phenotypes were rescued by Dalpha1 transgenes, but not by Dalpha2 or Dalpha3 transgenes. Genetic interactions between the ectopic expression of Dalpha1 and the karyopherins CAS and importin beta1 suggest that high nuclear levels of Dalpha1 are deleterious. We conclude that Dalpha1 performs paralog-specific activities that are essential for gametogenesis and that regulation of subcellular Dalpha1 localization may affect cell fate decisions. The initial expansion and specialization of the animal importin alpha-gene family may have been driven by the specialized needs of gametogenesis. These results provide a framework for studies of the more complex mammalian importin alpha-gene family.     

利用串联亲和纯化的方法筛选耻垢分枝杆菌中MutM的相互作用蛋白

Mut M(formamidopyrimidine-DNA glycosylase,Fpg)是原核生物碱基切除修复系统(BER)中同时具有DNA糖苷酶和脱嘌呤/脱嘧啶AP裂解酶活性的一种双功能酶,不但可以识别DNA损伤,而且能切除损伤的碱基,从而参与到许多种损伤的修复过程.除了高致突变率的8-羟基鸟嘌呤(8-oxoguanine,8-oxo G)外,Mut M在其他损伤修复中具体作用机制还不清楚.本研究主要以耻垢分枝杆菌(M.smegmatis)为研究对象,利用串联亲和纯化技术和质谱相结合的方法对可能与Mut M相互作用的蛋白因子进行发现和鉴定,并于体外用Far-western和GST pull-down方法对鉴定出的蛋白DEAD-box rna helicase、Rps C、Uvr A与Mut M的相互作用进行了验证.实验结果表明,利用串联亲和纯化方法来发现Mut M相互作用的蛋白是切实可行的.本研究为进一步深入研究Mut M在其参与的损伤修复中的具体机制提供了切入点.     

Dsc Orthologs Are Required for Hypoxia Adaptation,Triazole Drug Responses,and Fungal Virulence in Aspergillus fumigatus

Hypoxia is an environmental stress encountered by Aspergillus fumigatus during invasive pulmonary aspergillosis (IPA). The ability of this mold to adapt to hypoxia is important for fungal virulence and genetically regulated in part by the sterol regulatory element binding protein (SREBP) SrbA. SrbA is required for fungal growth in the murine lung and to ultimately cause lethal disease in murine models of IPA. Here we identified and partially characterized four genes (dscA, dscB, dscC, and dscD, here referred to as dscA-D) with previously unknown functions in A. fumigatus that are orthologs of the Schizosaccharomyces pombe genes dsc1, dsc2, dsc3, and dsc4 (dsc1-4), which encode a Golgi E3 ligase complex critical for SREBP activation by proteolytic cleavage. A. fumigatus null dscA-D mutants displayed remarkable defects in hypoxic growth and increased susceptibility to triazole antifungal drugs. Consistent with the confirmed role of these genes in S. pombe, both ΔdscA and ΔdscC resulted in reduced cleavage of the SrbA precursor protein in A. fumigatus. Inoculation of corticosteroid immunosuppressed mice with ΔdscA and ΔdscC strains revealed that these genes are critical for A. fumigatus virulence. Reintroduction of SrbA amino acids 1 to 425, encompassing the N terminus DNA binding domain, into the ΔdscA strain was able to partially restore virulence, further supporting a mechanistic link between DscA and SrbA function. Thus, we have shown for the first time the importance of a previously uncharacterized group of genes in A. fumigatus that mediate hypoxia adaptation, fungal virulence, and triazole drug susceptibility and that are likely linked to regulation of SrbA function.     

Female college students and cosmetic surgery: an investigation of experiences, attitudes, and body image

This large, multisite study investigated female college students' experiences with and attitudes about cosmetic surgery. The study also assessed the relationship between several aspects of body image, including appearance satisfaction and investment and symptoms of body dysmorphic disorder, and interest in cosmetic surgery. Thirty (5 percent) of the 559 women surveyed reported that they had undergone cosmetic surgery. Two thirds of respondents reported knowing someone who had received cosmetic surgery, and approximately one third indicated that a family member had undergone surgery. Overall, participants held relatively favorable attitudes about surgery. Regression analysis suggested that a greater psychological investment in physical appearance and greater internalization of mass media images of beauty predicted more favorable attitudes toward cosmetic surgery. Fourteen women (2.5 percent) screened positive for body dysmorphic disorder based on the nature and severity of their self-reported body-image concerns. Results of this study provide new information on young women's experiences and attitudes about cosmetic surgery and how these attitudes relate to body image.     

A rab protein regulates the localization of secretory granules in AtT-20 cells.

Low molecular weight (LMW) GTP-binding proteins are hypothesized to play a role in the vectorial transport of intracellular vesicles. Mutational studies in yeast and subcellular localization in mammalian cells suggest that a family of LMW GTP-binding proteins, termed rab, target intracellular vesicles to their appropriate acceptor compartment. In this report, we demonstrate that an elasmobranch homologue of rab3A, o-rab3, plays a significant role in the sequestration of regulated secretory vesicles. When transfected into the murine endocrine cell line AtT-20, the wild-type o-rab3 protein is localized exclusively to the tips of the processes, a region of the cell known to accumulate proteins associated with regulated secretory vesicles. Two mutations, Gln81 to Leu (Q81L) and Asn135 Ile (N135I), which alter GTP binding or rate of hydrolysis, blocked the localization of the o-rab3 protein to the tips of cell processes. These mutations also hindered the sequestration of ACTH-containing secretory vesicles to the process tips but did not affect the basal or stimulated release of ACTH. Moreover, the sequestration of the protein VAMP to the process tip was also hindered by the mutation. The results demonstrate a role for the rab3 proteins in localization, sequestration, and storage of secretory vesicles near their release site.