141 research outputs found

    RNA-Guided Genome Editing in Drosophila with the Purified Cas9 Protein

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    We report a method for generating Drosophila germline mutants effectively via injection of the complex of the purified Cas9 protein, tracrRNA, and gene-specific crRNAs, which may reduce delayed mutations because of the transient activity of the Cas9 protein, combined with the simple mutation detection in GO founders by the T7E1 assay.

    Semen-mediated enhancement of HIV infection is donor-dependent and correlates with the levels of SEVI

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    <p>Abstract</p> <p>Background</p> <p>HIV-1 is usually transmitted in the presence of semen. We have shown that semen boosts HIV-1 infection and contains fragments of prostatic acid phosphatase (PAP) forming amyloid aggregates termed SEVI (semen-derived enhancer of viral infection) that promote virion attachment to target cells. Despite its importance for the global spread of HIV-1, however, the effect of semen on virus infection is controversial.</p> <p>Results</p> <p>Here, we established methods allowing the meaningful analysis of semen by minimizing its cytotoxic effects and partly recapitulating the conditions encountered during sexual HIV-1 transmission. We show that semen rapidly and effectively enhances the infectivity of HIV-1, HIV-2, and SIV. This enhancement occurs independently of the viral genotype and coreceptor tropism as well as the virus producer and target cell type. Semen-mediated enhancement of HIV-1 infection was also observed under acidic pH conditions and in the presence of vaginal fluid. We further show that the potency of semen in boosting HIV-1 infection is donor dependent and correlates with the levels of SEVI.</p> <p>Conclusions</p> <p>Our results show that semen strongly enhances the infectivity of HIV-1 and other primate lentiviruses and that SEVI contributes to this effect. Thus, SEVI may play an important role in the sexual transmission of HIV-1 and addition of SEVI inhibitors to microbicides may improve their efficacy.</p

    Sulforaphane Increases Cyclin-Dependent Kinase Inhibitor, p21 Protein in Human Oral Carcinoma Cells and Nude Mouse Animal Model to Induce G2/M Cell Cycle Arrest

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    Previously, our group reported that sulforaphane (SFN), a naturally occurring chemopreventive agent from cruciferous vegetables, effectively inhibits the proliferation of KB and YD-10B human oral squamous carcinoma cells by causing apoptosis. In this study, treatment of 20 and 40 µM of SFN for 12 h caused a cell cycle arrest in the G2/M phase. Cell cycle arrest induced by SFN was associated with a significant increase in the p21 protein level and a decrease in cyclin B expression, but there was no change in the cyclin A protein level. In addition, SFN increased the p21 promoter activity significantly. Furthermore, SFN induced p21 protein expression in a nude mouse xenograft model suggesting that SFN is a potent inducer of the p21 protein in human oral squamous carcinoma cells. These findings show that SFN is a promising candidate for molecular-targeting chemotherapy against human oral squamous cell carcinoma

    Childhood Cancer Mortality and Birth Characteristics in Korea: A National Population-based Birth Cohort Study

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    To examine the relationship between birth characteristics and childhood cancer mortality, a retrospective cohort study of Korean children was conducted using data collected by the national birth register between 1995 and 2006, which were then individually linked to death data. A cohort of 6,479,406 children was followed from birth until their death or until December 31, 2006. Poisson regression analyses were used to calculate rate ratios of childhood cancer deaths according to birth characteristics. A total of 1,469 cancer deaths were noted and the childhood cancer mortality rate was found to be 3.43 per 100,000 person-years in Korea during the period of 1995-2006. The birth characteristics examined in this study (i.e. , birth weight, gestational age, multiple births, parental ages, and number of siblings) were generally found to be not significantly associated with childhood cancer mortality, and the associations did not vary meaningfully with gender nor with cancer sites. However, among children aged 5-11 yr, higher birth weight was associated with elevated childhood cancer mortality (rate ratio = 1.28, 95% confidence interval 1.04-1.58). Our results offer no overall associations between childhood cancer mortality and birth characteristics, but suggest that the association may be specific to age group

    Suppression of Lung Tumorigenesis by Leucine Zipper/EF Hand–Containing Transmembrane-1

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    Leucine zipper/EF hand-containing transmembrane-1 (LETM1) encodes for the human homologue of yeast Mdm38p, which is a mitochondria-shaping protein of unclear function. However, a previous study demonstrated that LETM1 served as an anchor protein for complex formation between mitochondria and ribosome, and regulated mitochondrial biogenesis.Therefore, we examine the possibility that LETM1 may function to regulate mitochondria and lung tumor growth. In this study, we addressed this question by studying in the effect of adenovirus-mediated LETM1 in the lung cancer cell and lung cancer model mice. To investigate the effects of adenovirus-LETM1 in vitro, we infected with adenovirus-LETM1 in A549 cells. Additionally, in vivo effects of LETM1 were evaluated on K-ras(LA1) mice, human non-small cell lung cancer model mice, by delivering the LETM1 via aerosol through nose-only inhalation system. The effects of LETM1 on lung cancer growth and AMPK related signals were evaluated. Adenovirus-mediated overexpression of LETM1 could induce destruction of mitochondria of lung cancer cells through depleting ATP and AMPK activation. Furthermore, adenoviral-LETM1 also altered Akt signaling and inhibited the cell cycle while facilitating apoptosis. Theses results demonstrated that adenovirus-LETM1 suppressed lung cancer cell growth in vitro and in vivo.Adenovirus-mediated LETM1 may provide a useful target for designing lung tumor prevention and treatment

    Prevalence and changes in chronic diseases among South Korean farmers: 1998 to 2005

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    <p>Abstract</p> <p>Background</p> <p>Epidemiologic studies have suggested a unique pattern of disease among farmers in Western countries, but limited information is available about the magnitude of disease prevalence and their changes over time in Asian farmers. The aim of this study was to compare the prevalence and changes in chronic diseases among farmers with those of other occupational groups in South Korea.</p> <p>Methods</p> <p>Using data from three consecutive cross-sectional national surveys: the Korean National Health and Nutrition Examination Survey 1998 (n = 39,060), 2001 (n = 37,769), and 2005 (n = 34,145), we calculated age and gender-standardized prevalence of chronic diseases by the direct method and compared the prevalence changes from 1998 to 2005.</p> <p>Results</p> <p>Female farmers had significantly higher chronic disease prevalence than other occupational groups in all three surveys. Arthritis was the most prevalent chronic disease among farmers for both men and women. Compared with other populations, farmers demonstrated a higher prevalence of arthritis and intervertebral disc disorders. Farmers showed higher prevalence changes for intervertebral disc disorders than other occupational workers.</p> <p>Conclusion</p> <p>Our findings support that South Korean farmers have a distinct pattern of diseases prevalence from other populations. More detailed studies investigating the risk of musculoskeletal diseases and intensive intervention efforts to reduce the prevalence these diseases, particularly among female farmers, are required.</p

    Tetherin-Driven Adaptation of Vpu and Nef Function and the Evolution of Pandemic and Nonpandemic HIV-1 Strains

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    Vpu proteins of pandemic HIV-1 M strains degrade the viral receptor CD4 and antagonize human tetherin to promote viral release and replication. We find that Vpus from SIVgsn, SIVmus and SIVmon infecting Cercopithecus primate species also degrade CD4 and antagonize tetherin. In contrast, SIVcpz, the immediate precursor of HIV-1, whose Vpu shares a common ancestry with SIVgsn/mus/mon Vpu, uses Nef rather than Vpu to counteract chimpanzee tetherin. Human tetherin, however, is resistant to Nef and thus poses a significant barrier to zoonotic transmission of SIVcpz to humans. Remarkably, Vpu from non-pandemic HIV-1 O strains are poor tetherin antagonists while those from the rare group N viruses do not degrade CD4. Thus, only HIV-1 M evolved a fully functional Vpu following the three independent cross-species transmissions that resulted in HIV-1 groups M, N, and O. This may explain why group M viruses are almost entirely responsible for the gobal HIV/AIDS pandemic
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