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Sample records for apobec3 restriction factors

  1. Different mutagenic potential of HIV-1 restriction factors APOBEC3G and APOBEC3F is determined by distinct single-stranded DNA scanning mechanisms.

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    Anjuman Ara

    2014-03-01

    Full Text Available The APOBEC3 deoxycytidine deaminase family functions as host restriction factors that can block replication of Vif (virus infectivity factor deficient HIV-1 virions to differing degrees by deaminating cytosines to uracils in single-stranded (-HIV-1 DNA. Upon replication of the (-DNA to (+DNA, the HIV-1 reverse transcriptase incorporates adenines opposite the uracils, thereby inducing C/G→T/A mutations that can functionally inactivate HIV-1. Although both APOBEC3F and APOBEC3G are expressed in cell types HIV-1 infects and are suppressed by Vif, there has been no prior biochemical analysis of APOBEC3F, in contrast to APOBEC3G. Using synthetic DNA substrates, we characterized APOBEC3F and found that similar to APOBEC3G; it is a processive enzyme and can deaminate at least two cytosines in a single enzyme-substrate encounter. However, APOBEC3F scanning movement is distinct from APOBEC3G, and relies on jumping rather than both jumping and sliding. APOBEC3F jumping movements were also different from APOBEC3G. The lack of sliding movement from APOBEC3F is due to an ¹⁹⁰NPM¹⁹² motif, since insertion of this motif into APOBEC3G decreases its sliding movements. The APOBEC3G NPM mutant induced significantly less mutations in comparison to wild-type APOBEC3G in an in vitro model HIV-1 replication assay and single-cycle infectivity assay, indicating that differences in DNA scanning were relevant to restriction of HIV-1. Conversely, mutation of the APOBEC3F ¹⁹¹Pro to ¹⁹¹Gly enables APOBEC3F sliding movements to occur. Although APOBEC3F ¹⁹⁰NGM¹⁹² could slide, the enzyme did not induce more mutagenesis than wild-type APOBEC3F, demonstrating that the unique jumping mechanism of APOBEC3F abrogates the influence of sliding on mutagenesis. Overall, we demonstrate key differences in the impact of APOBEC3F- and APOBEC3G-induced mutagenesis on HIV-1 that supports a model in which both the processive DNA scanning mechanism and preferred

  2. Identification of an HIV-1 replication inhibitor which rescues host restriction factor APOBEC3G in Vif-APOBEC3G complex.

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    Zhang, Shaoyang; Zhong, Limei; Chen, Bing; Pan, Ting; Zhang, Xue; Liang, Liting; Li, Qianwen; Zhang, Ziying; Chen, Hui; Zhou, Jie; Luo, Haihua; Zhang, Hui; Bai, Chuan

    2015-10-01

    HIV-1 Vif protein is one of the most crucial accessory proteins for viral replication. It efficiently counteracts the important host restriction factor APOBEC3G (apolipoprotein B mRNA-editing enzyme, catalytic polypeptide-like 3G, A3G) which is lethal to HIV-1 by causing G to A mutation of viral genome. Vif protein mediates degradation of APOBEC3G via the complicated protein-protein interactions of Vif, APOBEC3G, Elongin C/B and Cullin 5. The importance of Vif-APOBEC3G complex makes it a good potential target to develop new therapeutics of HIV-1. We identified a potent HIV-1 replication inhibitor (ZBMA-1, IC50 = 1.01 μM) that efficiently protected APOBEC3G protein by targeting Vif-APOBEC3G complex. The co-immunoprecipitation and docking studies indicated that compound ZBMA-1 affected the binding of Elongin C with Vif protein.

  3. A novel HIV-1 restriction factor that is biologically distinct from APOBEC3 cytidine deaminases in a human T cell line CEM.NKR

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    Zhou Tao

    2009-04-01

    Full Text Available Abstract Background Isolation of novel retroviral restriction factors will open new avenues for anti-HIV/AIDS treatment. Although HIV-1 replication is restricted by APOBEC3G/APOBEC3F, TRIM5α, and CD317, none defend HIV-1 infection under natural conditions. Previously, we demonstrated a host factor from the human T cell line CEM.NKR that potently restricted wild-type HIV-1 replication. Interestingly, this restriction resembled the APOBEC3G/APOBEC3F pattern in that viral replication was inhibited from the second round of replication cycle at a post-entry step. Results Here, we further characterized this factor and found it distinguishable from the known anti-HIV APOBEC3 proteins. Although CEM.NKR cells expressed both APOBEC3G and APOBEC3F, their levels were at least 10 or 4-fold lower than those in H9 cells, and importantly, Vif effectively neutralized their activity. Among eight subclones isolated from CEM.NKR cells, one was relatively permissive, four were semi-permissive, and three were completely non-permissive for HIV-1 replication. When the levels of APOBEC3 expression were determined, all these clones retained similar low levels of APOBEC3DE, APOBEC3F, APOBEC3G and APOBEC3H expression, and no APOBEC3B expression was detected. Since the vif from SIVmac can effectively neutralize APOBEC3B and APOBEC3H, recombinant HIV-1 expressing this SIV gene were created. However, these viruses still failed to replicate in CEM.NKR cells. We also confirmed that HIV-1 restriction in CEM.NKR was not due to a loss of calnexin expression. Conclusion Taken together, these results not only demonstrate that all these aforementioned anti-HIV APOBEC3 proteins do not contribute to this HIV-1 restriction, but also shed light on a novel and potent HIV-1 inhibitor in CEM.NKR cells.

  4. HIV-1 viral infectivity factor (Vif) alters processive single-stranded DNA scanning of the retroviral restriction factor APOBEC3G.

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    Feng, Yuqing; Love, Robin P; Chelico, Linda

    2013-03-01

    APOBEC3G is a retroviral restriction factor that can inhibit the replication of human immunodeficiency virus, type 1 (HIV-1) in the absence of the viral infectivity factor (Vif) protein. Virion-encapsidated APOBEC3G can deaminate cytosine to uracil in viral (-)DNA, which leads to hypermutation and inactivation of the provirus. APOBEC3G catalyzes these deaminations processively on single-stranded DNA using sliding and jumping movements. Vif is thought to primarily overcome APOBEC3G through an interaction that mediates APOBEC3G ubiquitination and results in its proteasomal degradation. However, Vif may also inhibit APOBEC3G mRNA translation, virion encapsidation, and deamination activity. Here we investigated the molecular mechanism of VifIIIB- and VifHXB2-mediated inhibition of APOBEC3G deamination activity. Biochemical assays using a model HIV-1 replication assay and synthetic single-stranded or partially double-stranded DNA substrates demonstrated that APOBEC3G has an altered processive mechanism in the presence of Vif. Specifically, VifHXB2 inhibited the jumping and VifIIIB inhibited the sliding movements of APOBEC3G. The absence of such an effect by Vif on degradation-resistant APOBEC3G D128K indicates that a Vif-APOBEC3G interaction mediates this effect. That the partially processive APOBEC3G was less effective at inducing mutagenesis in a model HIV-1 replication assay suggests that Vif co-encapsidation with APOBEC3G can promote sublethal mutagenesis of HIV-1 proviral DNA.

  5. HIV restriction by APOBEC3 in humanized mice.

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    John F Krisko

    2013-03-01

    Full Text Available Innate immune restriction factors represent important specialized barriers to zoonotic transmission of viruses. Significant consideration has been given to their possible use for therapeutic benefit. The apolipoprotein B mRNA editing enzyme catalytic polypeptide 3 (APOBEC3 family of cytidine deaminases are potent immune defense molecules capable of efficiently restricting endogenous retroelements as well as a broad range of viruses including Human Immunodeficiency virus (HIV, Hepatitis B virus (HBV, Human Papilloma virus (HPV, and Human T Cell Leukemia virus (HTLV. The best characterized members of this family are APOBEC3G (A3G and APOBEC3F (A3F and their restriction of HIV. HIV has evolved to counteract these powerful restriction factors by encoding an accessory gene designated viral infectivity factor (vif. Here we demonstrate that APOBEC3 efficiently restricts CCR5-tropic HIV in the absence of Vif. However, our results also show that CXCR4-tropic HIV can escape from APOBEC3 restriction and replicate in vivo independent of Vif. Molecular analysis identified thymocytes as cells with reduced A3G and A3F expression. Direct injection of vif-defective HIV into the thymus resulted in viral replication and dissemination detected by plasma viral load analysis; however, vif-defective viruses remained sensitive to APOBEC3 restriction as extensive G to A mutation was observed in proviral DNA recovered from other organs. Remarkably, HIV replication persisted despite the inability of HIV to develop resistance to APOBEC3 in the absence of Vif. Our results provide novel insight into a highly specific subset of cells that potentially circumvent the action of APOBEC3; however our results also demonstrate the massive inactivation of CCR5-tropic HIV in the absence of Vif.

  6. Suppression of APOBEC3-mediated restriction of HIV-1 by Vif.

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    Feng, Yuqing; Baig, Tayyba T; Love, Robin P; Chelico, Linda

    2014-01-01

    The APOBEC3 restriction factors are a family of deoxycytidine deaminases that are able to suppress replication of viruses with a single-stranded DNA intermediate by inducing mutagenesis and functional inactivation of the virus. Of the seven human APOBEC3 enzymes, only APOBEC3-D, -F, -G, and -H appear relevant to restriction of HIV-1 in CD4+ T cells and will be the focus of this review. The restriction of HIV-1 occurs most potently in the absence of HIV-1 Vif that induces polyubiquitination and degradation of APOBEC3 enzymes through the proteasome pathway. To restrict HIV-1, APOBEC3 enzymes must be encapsidated into budding virions. Upon infection of the target cell during reverse transcription of the HIV-1 RNA into (-)DNA, APOBEC3 enzymes deaminate cytosines to form uracils in single-stranded (-)DNA regions. Upon replication of the (-)DNA to (+)DNA, the HIV-1 reverse transcriptase incorporates adenines opposite to the uracils thereby inducing C/G to T/A mutations that can functionally inactivate HIV-1. APOBEC3G is the most studied APOBEC3 enzyme and it is known that Vif attempts to thwart APOBEC3 function not only by inducing its proteasomal degradation but also by several degradation-independent mechanisms, such as inhibiting APOBEC3G virion encapsidation, mRNA translation, and for those APOBEC3G molecules that still become virion encapsidated, Vif can inhibit APOBEC3G mutagenic activity. Although most Vif variants can induce efficient degradation of APOBEC3-D, -F, and -G, there appears to be differential sensitivity to Vif-mediated degradation for APOBEC3H. This review examines APOBEC3-mediated HIV restriction mechanisms, how Vif acts as a substrate receptor for a Cullin5 ubiquitin ligase complex to induce degradation of APOBEC3s, and the determinants and functional consequences of the APOBEC3 and Vif interaction from a biological and biochemical perspective.

  7. Suppression of APOBEC3-mediated restriction of HIV-1 by Vif

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    Yuqing eFeng

    2014-08-01

    Full Text Available The APOBEC3 restriction factors are a family of deoxycytidine deaminases that are able to suppress replication of viruses with a single-stranded DNA intermediate by inducing mutagenesis and functional inactivation of the virus. Of the seven human APOBEC3 enzymes, only APOBEC3-D, -F, -G, and -H appear relevant to restriction of HIV-1 in CD4+ T cells and will be the focus of this review. The restriction of HIV-1 occurs most potently in the absence of HIV-1 Vif that induces polyubiquitination and degradation of APOBEC3 enzymes through the proteasome pathway. To restrict HIV-1, APOBEC3 enzymes must be encapsidated into budding virions. Upon infection of the target cell during reverse transcription of the HIV-1 RNA into (-DNA APOBEC3 enzymes deaminate cytosines to forms uracils in single-stranded (- DNA regions. Upon replication of the (-DNA to (+DNA, the HIV-1 reverse transcriptase incorporates adenines opposite the uracils thereby inducing C/G to T/A mutations that can functionally inactivate HIV-1. APOBEC3G is the most studied APOBEC3 enzyme and it is known that Vif attempts to thwart APOBEC3 function not only by inducing its proteasomal degradation but by several degradation-independent mechanisms such as inhibiting APOBEC3G virion encapsidation, mRNA translation, and for those APOBEC3G molecules that still become virion encapsidated, Vif can inhibit APOBEC3G mutagenic activity. Although most Vif variants can induce efficient degradation of APOBEC3-D, -F, and -G, there appears to be differential sensitivity to Vif-mediated degradation for APOBEC3H. This review examines APOBEC3-mediated HIV restriction mechanisms, how Vif acts as a substrate receptor for a Cullin5 ubiquitin ligase complex to induce degradation of APOBEC3s, and the determinants and functional consequences of the APOBEC3 and Vif interaction from a biological and biochemical perspective.

  8. Vif proteins of human and simian immunodeficiency viruses require cellular CBFβ to degrade APOBEC3 restriction factors.

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    Hultquist, Judd F; Binka, Mawuena; LaRue, Rebecca S; Simon, Viviana; Harris, Reuben S

    2012-03-01

    HIV-1 requires the cellular transcription factor CBFβ to stabilize its accessory protein Vif and promote APOBEC3G degradation. Here, we demonstrate that both isoforms of CBFβ allow for increased steady-state levels of Vif, enhanced APOBEC3G degradation, and increased viral infectivity. This conserved functional interaction enhances the steady-state levels of Vif proteins from multiple HIV-1 subtypes and is required for the degradation of all human and rhesus Vif-sensitive APOBEC3 proteins by their respective lentiviral Vif proteins.

  9. Vif of feline immunodeficiency virus from domestic cats protects against APOBEC3 restriction factors from many felids.

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    Zielonka, Jörg; Marino, Daniela; Hofmann, Henning; Yuhki, Naoya; Löchelt, Martin; Münk, Carsten

    2010-07-01

    To get more insight into the role of APOBEC3 (A3) cytidine deaminases in the species-specific restriction of feline immunodeficiency virus (FIV) of the domestic cat, we tested the A3 proteins present in big cats (puma, lion, tiger, and lynx). These A3 proteins were analyzed for expression and sensitivity to the Vif protein of FIV. While A3Z3s and A3Z2-Z3s inhibited Deltavif FIV, felid A3Z2s did not show any antiviral activity against Deltavif FIV or wild-type (wt) FIV. All felid A3Z3s and A3Z2-Z3s were sensitive to Vif of the domestic cat FIV. Vif also induced depletion of felid A3Z2s. Tiger A3s showed a moderate degree of resistance against the Vif-mediated counter defense. These findings may imply that the A3 restriction system does not play a major role to prevent domestic cat FIV transmission to other Felidae. In contrast to the sensitive felid A3s, many nonfelid A3s actively restricted wt FIV replication. To test whether Vif(FIV) can protect also the distantly related human immunodeficiency virus type 1 (HIV-1), a chimeric HIV-1.Vif(FIV) was constructed. This HIV-1.Vif(FIV) was replication competent in nonpermissive feline cells expressing human CD4/CCR5 that did not support the replication of wt HIV-1. We conclude that the replication of HIV-1 in some feline cells is inhibited only by feline A3 restriction factors and the absence of the appropriate receptor or coreceptor.

  10. Catalytic activity of APOBEC3F is required for efficient restriction of Vif-deficient human immunodeficiency virus.

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    Albin, John S; Brown, William L; Harris, Reuben S

    2014-02-01

    APOBEC3 proteins are DNA cytosine deaminases that restrict the replication of human immunodeficiency virus deficient in the counterdefense protein Vif. Here, we address the capacity of APOBEC3F to restrict via deaminase-dependent and -independent mechanisms by monitoring spreading infections in diverse T cell lines. Our data indicate that only a deaminase-proficient protein is capable of long-term restriction of Vif-deficient HIV in T cells, analogous to prior reports for APOBEC3G. This indicates that the principal mechanism of APOBEC3F restriction is deaminase-dependent.

  11. Subcellular localization of the APOBEC3 proteins during mitosis and implications for genomic DNA deamination.

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    Lackey, Lela; Law, Emily K; Brown, William L; Harris, Reuben S

    2013-03-01

    Humans have seven APOBEC3 DNA cytosine deaminases. The activity of these enzymes allows them to restrict a variety of retroviruses and retrotransposons, but may also cause pro-mutagenic genomic uracil lesions. During interphase the APOBEC3 proteins have different subcellular localizations: cell-wide, cytoplasmic or nuclear. This implies that only a subset of APOBEC3s have contact with nuclear DNA. However, during mitosis, the nuclear envelope breaks down and cytoplasmic proteins may enter what was formerly a privileged zone. To address the hypothesis that all APOBEC3 proteins have access to genomic DNA, we analyzed the localization of the APOBEC3 proteins during mitosis. We show that APOBEC3A, APOBEC3C and APOBEC3H are excluded from condensed chromosomes, but become cell-wide during telophase. However, APOBEC3B, APOBEC3D, APOBEC3F and APOBEC3G are excluded from chromatin throughout mitosis. After mitosis, APOBEC3B becomes nuclear, and APOBEC3D, APOBEC3F and APOBEC3G become cytoplasmic. Both structural motifs as well as size may be factors in regulating chromatin exclusion. Deaminase activity was not dependent on cell cycle phase. We also analyzed APOBEC3-induced cell cycle perturbations as a measure of each enzyme's capacity to inflict genomic DNA damage. AID, APOBEC3A and APOBEC3B altered the cell cycle profile, and, unexpectedly, APOBEC3D also caused changes. We conclude that several APOBEC3 family members have access to the nuclear compartment and can impede the cell cycle, most likely through DNA deamination and the ensuing DNA damage response. Such genomic damage may contribute to carcinogenesis, as demonstrated by AID in B cell cancers and, recently, APOBEC3B in breast cancers.

  12. Inhibition of a NEDD8 Cascade Restores Restriction of HIV by APOBEC3G.

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    David J Stanley

    2012-12-01

    Full Text Available Cellular restriction factors help to defend humans against human immunodeficiency virus (HIV. HIV accessory proteins hijack at least three different Cullin-RING ubiquitin ligases, which must be activated by the small ubiquitin-like protein NEDD8, in order to counteract host cellular restriction factors. We found that conjugation of NEDD8 to Cullin-5 by the NEDD8-conjugating enzyme UBE2F is required for HIV Vif-mediated degradation of the host restriction factor APOBEC3G (A3G. Pharmacological inhibition of the NEDD8 E1 by MLN4924 or knockdown of either UBE2F or its RING-protein binding partner RBX2 bypasses the effect of Vif, restoring the restriction of HIV by A3G. NMR mapping and mutational analyses define specificity determinants of the UBE2F NEDD8 cascade. These studies demonstrate that disrupting host NEDD8 cascades presents a novel antiretroviral therapeutic approach enhancing the ability of the immune system to combat HIV.

  13. Core-binding factor subunit beta is not required for non-primate lentiviral Vif-mediated APOBEC3 degradation.

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    Ai, Youwei; Zhu, Dantong; Wang, Cuihui; Su, Chao; Ma, Jian; Ma, Jianzhang; Wang, Xiaojun

    2014-10-01

    Viral infectivity factor (Vif) is required for lentivirus fitness and pathogenicity, except in equine infectious anemia virus (EIAV). Vif enhances viral infectivity by a Cullin5-Elongin B/C E3 complex to inactivate the host restriction factor APOBEC3. Core-binding factor subunit beta (CBF-β) is a cell factor that was recently shown to be important for the primate lentiviral Vif function. Non-primate lentiviral Vif also degrades APOBEC3 through the proteasome pathway. However, it is unclear whether CBF-β is required for the non-primate lentiviral Vif function. In this study, we demonstrated that the Vifs of non-primate lentiviruses, including feline immunodeficiency virus (FIV), bovine immunodeficiency virus (BIV), caprine arthritis encephalitis virus (CAEV), and maedi-visna virus (MVV), do not interact with CBF-β. In addition, CBF-β did not promote the stability of FIV, BIV, CAEV, and MVV Vifs. Furthermore, CBF-β silencing or overexpression did not affect non-primate lentiviral Vif-mediated APOBEC3 degradation. Our results suggest that non-primate lentiviral Vif induces APOBEC3 degradation through a different mechanism than primate lentiviral Vif. Importance: The APOBEC3 protein family members are host restriction factors that block retrovirus replication. Vif, an accessory protein of lentivirus, degrades APOBEC3 to rescue viral infectivity by forming Cullin5-Elongin B/C-based E3 complex. CBF-β was proved to be a novel regulator of primate lentiviral Vif function. In this study, we found that CBF-β knockdown or overexpression did not affect FIV Vif's function, which induced polyubiquitination and degradation of APOBEC3 by recruiting the E3 complex in a manner similar to that of HIV-1 Vif. We also showed that other non-primate lentiviral Vifs did not require CBF-β to degrade APOBEC3. CBF-β did not interact with non-primate lentiviral Vifs or promote their stability. These results suggest that a different mechanism exists for the Vif-APOBEC interaction and

  14. APOBEC3D and APOBEC3F potently promote HIV-1 diversification and evolution in humanized mouse model.

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    Kei Sato

    2014-10-01

    Full Text Available Several APOBEC3 proteins, particularly APOBEC3D, APOBEC3F, and APOBEC3G, induce G-to-A hypermutations in HIV-1 genome, and abrogate viral replication in experimental systems, but their relative contributions to controlling viral replication and viral genetic variation in vivo have not been elucidated. On the other hand, an HIV-1-encoded protein, Vif, can degrade these APOBEC3 proteins via a ubiquitin/proteasome pathway. Although APOBEC3 proteins have been widely considered as potent restriction factors against HIV-1, it remains unclear which endogenous APOBEC3 protein(s affect HIV-1 propagation in vivo. Here we use a humanized mouse model and HIV-1 with mutations in Vif motifs that are responsible for specific APOBEC3 interactions, DRMR/AAAA (4A or YRHHY/AAAAA (5A, and demonstrate that endogenous APOBEC3D/F and APOBEC3G exert strong anti-HIV-1 activity in vivo. We also show that the growth kinetics of 4A HIV-1 negatively correlated with the expression level of APOBEC3F. Moreover, single genome sequencing analyses of viral RNA in plasma of infected mice reveal that 4A HIV-1 is specifically and significantly diversified. Furthermore, a mutated virus that is capable of using both CCR5 and CXCR4 as entry coreceptor is specifically detected in 4A HIV-1-infected mice. Taken together, our results demonstrate that APOBEC3D/F and APOBEC3G fundamentally work as restriction factors against HIV-1 in vivo, but at the same time, that APOBEC3D and APOBEC3F are capable of promoting viral diversification and evolution in vivo.

  15. A novel role for APOBEC3: Susceptibility to sexual transmission of murine acquired immunodeficiency virus (mAIDS is aggravated in APOBEC3 deficient mice

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    Jones Philip H

    2012-06-01

    Full Text Available Abstract Background APOBEC3 proteins are host factors that restrict infection by retroviruses like HIV, MMTV, and MLV and are variably expressed in hematopoietic and non-hematopoietic cells, such as macrophages, lymphocytes, dendritic, and epithelia cells. Previously, we showed that APOBEC3 expressed in mammary epithelia cells function to limit milk-borne transmission of the beta-retrovirus, mouse mammary tumor virus. In this present study, we used APOBEC3 knockout mice and their wild type counterpart to query the role of APOBEC3 in sexual transmission of LP-BM5 MLV – the etiological agent of murine AIDs (mAIDs. Results We show that mouse APOBEC3 is expressed in murine genital tract tissues and gametes and that genital tract tissue of APOBEC3-deficient mice are more susceptible to infection by LP-BM5 virus. APOBEC3 expressed in genital tract tissues most likely plays a role in decreasing virus transmission via the sexual route, since mice deficient in APOBEC3 gene have higher genitalia and seminal plasma virus load and sexually transmit the virus more efficiently to their partners compared to APOBEC3+ mice. Moreover, we show that female mice sexually infected with LP-BM5 virus transmit the virus to their off-spring in APOBEC3-dependent manner. Conclusion Our data indicate that genital tissue intrinsic APOBEC3 restricts genital tract infection and limits sexual transmission of LP-BM5 virus.

  16. Endogenous APOBEC3B restricts LINE-1 retrotransposition in transformed cells and human embryonic stem cells.

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    Wissing, Silke; Montano, Mauricio; Garcia-Perez, Jose Luis; Moran, John V; Greene, Warner C

    2011-10-21

    Members of the APOBEC3 (A3) family of cytidine deaminase enzymes act as host defense mechanisms limiting both infections by exogenous retroviruses and mobilization of endogenous retrotransposons. Previous studies revealed that the overexpression of some A3 proteins could restrict engineered human Long INterspersed Element-1 (LINE-1 or L1) retrotransposition in HeLa cells. However, whether endogenous A3 proteins play a role in restricting L1 retrotransposition remains largely unexplored. Here, we show that HeLa cells express endogenous A3B and A3C, whereas human embryonic stem cells (hESCs) express A3B, A3C, A3DE, A3F, and A3G. To study the relative contribution of endogenous A3 proteins in restricting L1 retrotransposition, we first generated small hairpin RNAs (shRNAs) to suppress endogenous A3 mRNA expression, and then assessed L1 mobility using a cell-based L1 retrotransposition assay. We demonstrate that in both HeLa and hESCs, shRNA-based knockdown of A3B promotes a ∼2-3.7-fold increase in the retrotransposition efficiency of an engineered human L1. Knockdown of the other A3s produced no significant increase in L1 activity. Thus, A3B appears to restrict engineered L1 retrotransposition in a broad range of cell types, including pluripotent cells.

  17. Host Restriction of Lentiviruses and Viral Countermeasures: APOBEC3 and Vif

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    Valgerdur Andrésdóttir

    2013-07-01

    Full Text Available It is becoming increasingly clear that organisms have developed a variety of mechanisms to fight against viral infection. The viruses have developed means of counteracting these defences in various ways. The APOBEC3 proteins are a mammalian-specific family of nucleic acid cytidine deaminases that block retroviral infection. These inhibitors are counteracted by the Vif proteins encoded by most lentiviruses. In this paper, we will review the interaction of the lentiviral Vif proteins with the APOBEC3 proteins, with an emphasis on sheep APOBEC3 and maedi-visna virus (MVV Vif.

  18. Structural determinants of HIV-1 Vif susceptibility and DNA binding in APOBEC3F.

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    Siu, Karen K; Sultana, Azmiri; Azimi, Farshad C; Lee, Jeffrey E

    2013-01-01

    The human APOBEC3 family of DNA cytosine deaminases serves as a front-line intrinsic immune response to inhibit the replication of diverse retroviruses. APOBEC3F and APOBEC3G are the most potent factors against HIV-1. As a countermeasure, HIV-1 viral infectivity factor (Vif) targets APOBEC3s for proteasomal degradation. Here we report the crystal structure of the Vif-binding domain in APOBEC3F and a novel assay to assess Vif-APOBEC3 binding. Our results point to an amphipathic surface that is conserved in APOBEC3s as critical for Vif susceptibility in APOBEC3F. Electrostatic interactions likely mediate Vif binding. Moreover, structure-guided mutagenesis reveals a straight ssDNA-binding groove distinct from the Vif-binding site, and an 'aromatic switch' is proposed to explain DNA substrate specificities across the APOBEC3 family. This study opens new lines of inquiry that will further our understanding of APOBEC3-mediated retroviral restriction and provides an accurate template for structure-guided development of inhibitors targeting the APOBEC3-Vif axis.

  19. APOBEC3G对HIV-1及其Vif缺失株的抑制作用%Restriction of HIV-1 and the Vif-deficiency strain by APOBEC3G

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    李岚; 曾毅

    2011-01-01

    Objective To study the restriction of HIV-1 and the Vif-deficient strain. Methods Viruses of HIV-1 wild type( BH10 WT) or the Vd-deficient strain( BH10 ΔVif) produced from transfected 293T cells were used to infect various cell lines, including MT4 and H9. The results were determined by reverse transcriptase ( RTase ) assay. Molecular-cloning technique was used to construct expression plasmid pEGFP-3G which express APOBEC3G with a C-terminal GFP tag. The virus strains of BH10 WT or BH10 ΔVif co-transfection with different dose of pEGFP-3G in 293T cells, and the expression of APOBEC3G-GFP was observed by live cell fluorescence microscopy. The infectivity of virus was determined by multinuclear activation of galactosidase indicator(MAGI) assay and RTase assay. Results BH10 WT replication in MT4 cells showed much faster replication kinetics than that in H9 cells, with peak RT values being observed as early as 4 days post-infection. RT activity of BH10 ΔVif in H9 cells was suppressed almost to the level of negative control and that in MT4 cells was observed on the 12th day. GFP-APOBEC3G and a GFP-only control localized to the cytoplasmic and cell-wide, respectively. The titer of BH10 ΔVif by MAGI assay is about 2.75 × 104 U/mL. The titer of viruses, produced in 293T cells by cotransfection with increasing amounts of APOBEC3G, was significantly reduced from 1.48 × 103 U/mL to 0.33 × 103 U/mL. The infectivity of BH10 ΔVif produced in the presence of 0.2 μg of co-transfected pEGFP-3G was twenty fold less infectious than BH10 ΔVif produced in the absence of APOBEC3G.Conclusion The anti-HIV activity of APOBEC3G was dose-dependent, and HIV-1 Vif has the essential role in the virus replication. Based on the results we would construct a new platform to accurately and promptly select efficacious drugs.%目的 研究细胞内在抗病毒因子APOBEC3G对HIV-1及其Vif缺失株的抑制作用.方法 HIV-1野生株病毒(BH10 WT)和Vif缺失株病毒(BH10

  20. Degradation of the cancer genomic DNA deaminase APOBEC3B by SIV Vif.

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    Land, Allison M; Wang, Jiayi; Law, Emily K; Aberle, Ryan; Kirmaier, Andrea; Krupp, Annabel; Johnson, Welkin E; Harris, Reuben S

    2015-11-24

    APOBEC3B is a newly identified source of mutation in many cancers, including breast, head/neck, lung, bladder, cervical, and ovarian. APOBEC3B is a member of the APOBEC3 family of enzymes that deaminate DNA cytosine to produce the pro-mutagenic lesion, uracil. Several APOBEC3 family members function to restrict virus replication. For instance, APOBEC3D, APOBEC3F, APOBEC3G, and APOBEC3H combine to restrict HIV-1 in human lymphocytes. HIV-1 counteracts these APOBEC3s with the viral protein Vif, which targets the relevant APOBEC3s for proteasomal degradation. While APOBEC3B does not restrict HIV-1 and is not targeted by HIV-1 Vif in CD4-positive T cells, we asked whether related lentiviral Vif proteins could degrade APOBEC3B. Interestingly, several SIV Vif proteins are capable of promoting APOBEC3B degradation, with SIVmac239 Vif proving the most potent. This likely occurs through the canonical polyubiquitination mechanism as APOBEC3B protein levels are restored by MG132 treatment and by altering a conserved E3 ligase-binding motif. We further show that SIVmac239 Vif can prevent APOBEC3B mediated geno/cytotoxicity and degrade endogenous APOBEC3B in several cancer cell lines. Our data indicate that the APOBEC3B degradation potential of SIV Vif is an effective tool for neutralizing the cancer genomic DNA deaminase APOBEC3B. Further optimization of this natural APOBEC3 antagonist may benefit cancer therapy.

  1. APOBEC3G-Augmented Stem Cell Therapy to Modulate HIV Replication: A Computational Study.

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    Iraj Hosseini

    Full Text Available The interplay between the innate immune system restriction factor APOBEC3G and the HIV protein Vif is a key host-retrovirus interaction. APOBEC3G can counteract HIV infection in at least two ways: by inducing lethal mutations on the viral cDNA; and by blocking steps in reverse transcription and viral integration into the host genome. HIV-Vif blocks these antiviral functions of APOBEC3G by impeding its encapsulation. Nonetheless, it has been shown that overexpression of APOBEC3G, or interfering with APOBEC3G-Vif binding, can efficiently block in vitro HIV replication. Some clinical studies have also suggested that high levels of APOBEC3G expression in HIV patients are correlated with increased CD4+ T cell count and low levels of viral load; however, other studies have reported contradictory results and challenged this observation. Stem cell therapy to replace a patient's immune cells with cells that are more HIV-resistant is a promising approach. Pre-implantation gene transfection of these stem cells can augment the HIV-resistance of progeny CD4+ T cells. As a protein, APOBEC3G has the advantage that it can be genetically encoded, while small molecules cannot. We have developed a mathematical model to quantitatively study the effects on in vivo HIV replication of therapeutic delivery of CD34+ stem cells transfected to overexpress APOBEC3G. Our model suggests that stem cell therapy resulting in a high fraction of APOBEC3G-overexpressing CD4+ T cells can effectively inhibit in vivo HIV replication. We extended our model to simulate the combination of APOBEC3G therapy with other biological activities, to estimate the likelihood of improved outcomes.

  2. 病毒感染因子在APOBEC3G抗病毒中的拮抗作用%Antagonistic Effect of Virion Infectivity Factor and APOBEC3G in the Intrinsic Antiretroviral Defense

    Institute of Scientific and Technical Information of China (English)

    王运华; 张耀洲

    2008-01-01

    病毒感染因子(virion infectivity factor, Vif)是人免疫缺陷病毒(human im_mu_n_o_de_fi_cien_cy virus, HIV)的6个辅助蛋白之一, 是病毒进行有效复制所必需的.由于Vif功能的复杂性以及对相应复合物体系的不了解, 一直以来, 对Vif的研究进展缓慢.直到2002年发现载脂蛋白B mRNA编辑酶催化多肽样蛋白3G (apolipoprotein B mRNA-editing enzyme catalytic polypeptide-like 3G, APOBEC3G)是存在于细胞内的一种天然抗病毒因子后, Vif的功能才被逐步阐明.APOBEC3G主要通过嘧啶脱氨基活性使HIV-1的负链DNA在逆转录过程中发生致死性超突变, 从而起到抗病毒作用.HIV-1基因编码Vif来拮抗APOBEC3G, 二者在宿主细胞内达到动态平衡.Vif通过介导APOBEC3G降解、减少在胞内的表达、阻碍其向病毒粒子的包装以及促使其装配成无活性的高分子质量复合体等多种途径起到中和作用.对Vif/APOBEC3G相互作用及其调节机制的进一步研究, 将为新型抗HIV-1病毒药物的研制与开发提供理论依据.

  3. APOBEC3F determinants of HIV-1 Vif sensitivity.

    Science.gov (United States)

    Land, Allison M; Shaban, Nadine M; Evans, Leah; Hultquist, Judd F; Albin, John S; Harris, Reuben S

    2014-11-01

    HIV-1 Vif counteracts restrictive APOBEC3 proteins by targeting them for proteasomal degradation. To determine the regions mediating sensitivity to Vif, we compared human APOBEC3F, which is HIV-1 Vif sensitive, with rhesus APOBEC3F, which is HIV-1 Vif resistant. Rhesus-human APOBEC3F chimeras and amino acid substitution mutants were tested for sensitivity to HIV-1 Vif. This approach identified the α3 and α4 helices of human APOBEC3F as important determinants of the interaction with HIV-1 Vif.

  4. Running Loose or Getting Lost: How HIV-1 Counters and Capitalizes on APOBEC3-Induced Mutagenesis through Its Vif Protein

    OpenAIRE

    Christel Kamp; Dieter Häussinger; Jörg Zielonka; Carsten Münk; Jensen, Björn-Erik O.

    2012-01-01

    Human immunodeficiency virus-1 (HIV-1) dynamics reflect an intricate balance within the viruses’ host. The virus relies on host replication factors, but must escape or counter its host’s antiviral restriction factors. The interaction between the HIV-1 protein Vif and many cellular restriction factors from the APOBEC3 protein family is a prominent example of this evolutionary arms race. The viral infectivity factor (Vif) protein largely neutralizes APOBEC3 proteins, which c...

  5. Species-specific differences in the ability of feline lentiviral Vif to degrade feline APOBEC3 proteins.

    Science.gov (United States)

    Yoshikawa, Rokusuke; Nakano, Yusuke; Yamada, Eri; Izumi, Taisuke; Misawa, Naoko; Koyanagi, Yoshio; Sato, Kei

    2016-04-01

    How host-virus co-evolutionary relationships manifest is one of the most intriguing issues in virology. To address this topic, the mammal-lentivirus relationship can be considered as an interplay of cellular and viral proteins, particularly apolipoprotein B mRNA editing enzyme catalytic polypeptide-like 3 (APOBEC3) and viral infectivity factor (Vif). APOBEC3s enzymatically restrict lentivirus replication, whereas Vif antagonizes the host anti-viral action mediated by APOBEC3. In this study, the focus was on the interplay between feline APOBEC3 proteins and two feline immunodeficiency viruses in cats and pumas. To our knowledge, this study provides the first evidence of non-primate lentiviral Vif being incapable of counteracting a natural host's anti-viral activity mediated via APOBEC3 protein.

  6. Antiviral Warrior-APOBEC3G

    Institute of Scientific and Technical Information of China (English)

    WU Xiao-xia; MA Yi-cai

    2005-01-01

    This paper is to further understand how APOBEC3G can defend the retroviruses and to find new approaches to AIDs (acquired immure deficiency syndrome).The viral infectivity factor (Vif) induces rapid degradation of APOBEC3G by ubiquitination, which is a proteosome-dependent pathway. Precisely speaking, only in the virus-producing cell Vif expression is necessary; in its absence, infection of a subsequent target cell terminates at a postentry step through the action of the human APOBEC3G antiviral mechanism. Vif protein has two domains: one binds to APOBEC3G and the other regulates the degradation of APOBEC3G by a conserved sequence, SLQ (Y/F) LA motif. Recently, the research on Vif has also revealed APOBEC3G is a novel component of innate immune system. In fact, APOBEC3G not only acts in DNA editing to block the replication of retroviruses such as HIV-1, but also is able to defend a wide spectrum of distantly related retroviruses and interferes with HBV through a different mechanism from HIV.

  7. APOBEC3G-UBA2 fusion as a potential strategy for stable expression of APOBEC3G and inhibition of HIV-1 replication

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    Li Lin

    2008-08-01

    Full Text Available Abstract Background Although APOBEC3G protein is a potent and innate anti-HIV-1 cellular factor, HIV-1 Vif counteracts the effect of APOBEC3G by promoting its degradation through proteasome-mediated proteolysis. Thus, any means that could prevent APOBEC3G degradation could potentially enhance its anti-viral effect. The UBA2 domain has been identified as an intrinsic stabilization signal that protects protein from proteasomal degradation. In this pilot study, we tested whether APOBEC3G, when it is fused with UBA2, can resist Vif-mediated proteasomal degradation and further inhibit HIV-1 infection. Results APOBEC3G-UBA2 fusion protein is indeed more resistant to Vif-mediated degradation than APOBEC3G. The ability of UBA2 domain to stabilize APOBEC3G was diminished when polyubiquitin was over-expressed and the APOBEC3G-UBA2 fusion protein was found to bind less polyubiquitin than APOBEC3G, suggesting that UBA2 stabilizes APOBEC3G by preventing ubiquitin chain elongation and proteasome-mediated proteolysis. Consistently, treatment of cells with a proteasome inhibitor MG132 alleviated protein degradation of APOBEC3G and APOBEC3G-UBA2 fusion proteins. Analysis of the effect of APOBEC3G-UBA2 fusion protein on viral infectivity indicated that infection of virus packaged from HEK293 cells expressing APOBEC3G-UBA2 fusion protein is significantly lower than those packaged from HEK293 cells over-producing APOBEC3G or APOBEC3G-UBA2 mutant fusion proteins. Conclusion Fusion of UBA2 to APOBEC3G can make it more difficult to be degraded by proteasome. Thus, UBA2 could potentially be used to antagonize Vif-mediated APOBEC3G degradation by preventing polyubiquitination. The stabilized APOBEC3G-UBA2 fusion protein gives stronger inhibitory effect on viral infectivity than APOBEC3G without UBA2.

  8. Vif determines the requirement for CBF-β in APOBEC3 degradation.

    Science.gov (United States)

    Yoshikawa, Rokusuke; Takeuchi, Junko S; Yamada, Eri; Nakano, Yusuke; Ren, Fengrong; Tanaka, Hiroshi; Münk, Carsten; Harris, Reuben S; Miyazawa, Takayuki; Koyanagi, Yoshio; Sato, Kei

    2015-04-01

    APOBEC3 (apolipoprotein B mRNA editing enzyme catalytic polypeptide-like 3) proteins are cellular DNA deaminases that restrict a broad spectrum of lentiviruses. This process is counteracted by Vif (viral infectivity factor) of lentiviruses, which binds APOBEC3s and promotes their degradation. CBF-β (core binding factor subunit β) is an essential co-factor for the function of human immunodeficiency virus type 1 Vif to degrade human APOBEC3s. However, the requirement for CBF-β in Vif-mediated degradation of other mammalian APOBEC3 proteins is less clear. Here, we determined the sequence of feline CBFB and performed phylogenetic analyses. These analyses revealed that mammalian CBFB is under purifying selection. Moreover, we demonstrated that CBF-β is dispensable for feline immunodeficiency virus Vif-mediated degradation of APOBEC3s of its host. These findings suggested that primate lentiviruses have adapted to use CBF-β, an evolutionary stable protein, to counteract APOBEC3 proteins of their hosts after diverging from other lentiviruses.

  9. HIV-1 Vif adaptation to human APOBEC3H haplotypes.

    Science.gov (United States)

    Ooms, Marcel; Brayton, Bonnie; Letko, Michael; Maio, Susan M; Pilcher, Christopher D; Hecht, Frederick M; Barbour, Jason D; Simon, Viviana

    2013-10-16

    Several human APOBEC3 deaminases can inhibit HIV-1 replication in vitro. HIV-1 Vif counteracts this restriction by targeting APOBEC3 for proteasomal degradation. Human APOBEC3H (A3H) is highly polymorphic, with natural variants differing considerably in anti-HIV-1 activity in vitro. To examine HIV-1 adaptation to variation in A3H activity in a natural infection context, we determined the A3H haplotypes and Vif sequences from 76 recently infected HIV-1 patients. We detected A3H-specific Vif changes suggesting viral adaptation. The patient-derived Vif sequences were used to engineer viruses that specifically differed in their ability to counteract A3H. Replication of these Vif-variant viruses in primary T cells naturally expressing active or inactive A3H haplotypes showed that endogenously expressed A3H restricts HIV-1 replication. Proviral DNA from A3H-restricted viruses showed high levels of G-to-A mutations in an A3H-specific GA dinucleotide context. Taken together, our data validate A3H expressed at endogenous levels as a bona fide HIV-1 restriction factor.

  10. APOBEC3A damages the cellular genome during DNA replication.

    Science.gov (United States)

    Green, Abby M; Landry, Sébastien; Budagyan, Konstantin; Avgousti, Daphne C; Shalhout, Sophia; Bhagwat, Ashok S; Weitzman, Matthew D

    2016-01-01

    The human APOBEC3 family of DNA-cytosine deaminases comprises 7 members (A3A-A3H) that act on single-stranded DNA (ssDNA). The APOBEC3 proteins function within the innate immune system by mutating DNA of viral genomes and retroelements to restrict infection and retrotransposition. Recent evidence suggests that APOBEC3 enzymes can also cause damage to the cellular genome. Mutational patterns consistent with APOBEC3 activity have been identified by bioinformatic analysis of tumor genome sequences. These mutational signatures include clusters of base substitutions that are proposed to occur due to APOBEC3 deamination. It has been suggested that transiently exposed ssDNA segments provide substrate for APOBEC3 deamination leading to mutation signatures within the genome. However, the mechanisms that produce single-stranded substrates for APOBEC3 deamination in mammalian cells have not been demonstrated. We investigated ssDNA at replication forks as a substrate for APOBEC3 deamination. We found that APOBEC3A (A3A) expression leads to DNA damage in replicating cells but this is reduced in quiescent cells. Upon A3A expression, cycling cells activate the DNA replication checkpoint and undergo cell cycle arrest. Additionally, we find that replication stress leaves cells vulnerable to A3A-induced DNA damage. We propose a model to explain A3A-induced damage to the cellular genome in which cytosine deamination at replication forks and other ssDNA substrates results in mutations and DNA breaks. This model highlights the risk of mutagenesis by A3A expression in replicating progenitor cells, and supports the emerging hypothesis that APOBEC3 enzymes contribute to genome instability in human tumors.

  11. Running loose or getting lost: how HIV-1 counters and capitalizes on APOBEC3-induced mutagenesis through its Vif protein.

    Science.gov (United States)

    Münk, Carsten; Jensen, Björn-Erik O; Zielonka, Jörg; Häussinger, Dieter; Kamp, Christel

    2012-11-14

    Human immunodeficiency virus-1 (HIV-1) dynamics reflect an intricate balance within the viruses’ host. The virus relies on host replication factors, but must escape or counter its host’s antiviral restriction factors. The interaction between the HIV-1 protein Vif and many cellular restriction factors from the APOBEC3 protein family is a prominent example of this evolutionary arms race. The viral infectivity factor (Vif) protein largely neutralizes APOBEC3 proteins, which can induce in vivo hypermutations in HIV-1 to the extent of lethal mutagenesis, and ensures the production of viable virus particles. HIV-1 also uses the APOBEC3-Vif interaction to modulate its own mutation rate in harsh or variable environments, and it is a model of adaptation in a coevolutionary setting. Both experimental evidence and the substantiation of the underlying dynamics through coevolutionary models are presented as complementary views of a coevolutionary arms race.

  12. Running Loose or Getting Lost: How HIV-1 Counters and Capitalizes on APOBEC3-Induced Mutagenesis through Its Vif Protein

    Directory of Open Access Journals (Sweden)

    Christel Kamp

    2012-11-01

    Full Text Available Human immunodeficiency virus-1 (HIV-1 dynamics reflect an intricate balance within the viruses’ host. The virus relies on host replication factors, but must escape or counter its host’s antiviral restriction factors. The interaction between the HIV-1 protein Vif and many cellular restriction factors from the APOBEC3 protein family is a prominent example of this evolutionary arms race. The viral infectivity factor (Vif protein largely neutralizes APOBEC3 proteins, which can induce in vivo hypermutations in HIV-1 to the extent of lethal mutagenesis, and ensures the production of viable virus particles. HIV-1 also uses the APOBEC3-Vif interaction to modulate its own mutation rate in harsh or variable environments, and it is a model of adaptation in a coevolutionary setting. Both experimental evidence and the substantiation of the underlying dynamics through coevolutionary models are presented as complementary views of a coevolutionary arms race.

  13. Association of APOBEC3G genotypes and CD4 decline in Thai and Cambodian HIV-infected children with moderate immune deficiency

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    Bunupuradah Torsak

    2012-11-01

    Full Text Available Abstract Introduction Human APOBEC3G is a host defense factor that potently inhibits HIV replication. We hypothesize that HIV-infected children with a genetic variant of APOBEC3G will have a more rapid disease progression. Methods Antiretroviral therapy (ART-naïve children, aged 1–12 years old with CD4 15-24% and without severe HIV-related symptoms were enrolled. The children had CD4% and absolute CD4 counts every 12 weeks and HIV-RNA every 24 weeks until 144 weeks. ART was started when CD4% declined to APOBEC3G genetic variants were performed by PCR-based restriction fragment length polymorphism techniques from peripheral blood mononuclear cells. Random-effect linear regression analysis was performed to correlate APOBEC3G genotypes and disease progression. Results 147 children, 35% male, with a median (IQR age of 6.5 (4.3-8.8 years were enrolled. CDC N:A:B were 1:63:36%. Median baseline values were 20% for CD4% 605 cells/mm3 for CD4 count and 4.7 log10copies/mL for HIV-RNA. The frequencies of APOBEC3G genotypes AA (186H/H, AG (186H/R, GG (186R/R were 86%, 12%, and 2% respectively. The APOBEC3G genotype GG was associated with a significant decline in CD4% -5.1% (−8.9 to −1.2%, p3, pAPOBEC3G genotypes with HIV-RNA changes overtime (p=0.16 or progression to CDC B and C (p=0.49 were observed. Conclusions APOBEC3G genotype GG was significantly associated with a more rapid decline in CD4. APOBEC3G’s antiviral effects on HIV disease progression in children should be further explored.

  14. APOBEC3G and APOBEC3F require an endogenous cofactor to block HIV-1 replication.

    Directory of Open Access Journals (Sweden)

    Yanxing Han

    2008-07-01

    Full Text Available APOBEC3G (A3G/APOBEC3F (A3F are two members of APOBEC3 cytidine deaminase subfamily. Although they potently inhibit the replication of vif-deficient HIV-1, this mechanism is still poorly understood. Initially, A3G/A3F were thought to catalyze C-to-U transitions on the minus-strand viral cDNAs during reverse transcription to disrupt the viral life cycle. Recently, it was found more likely that A3G/A3F directly interrupts viral reverse transcription or integration. In addition, A3G/A3F are both found in the high-molecular-mass complex in immortalized cell lines, where they interact with a number of different cellular proteins. However, there has been no evidence to prove that these interactions are required for A3G/A3F function. Here, we studied A3G/A3F-restricted HIV-1 replication in six different human T cell lines by infecting them with wild-type or vif-deficient HIV-1. Interestingly, in a CEM-derived cell line CEM-T4, which expresses high levels of A3G/A3F proteins, the vif-deficient virus replicated as equally well as the wild-type virus, suggesting that these endogenous antiretroviral genes lost anti-HIV activities. It was confirmed that these A3G/A3F genes do not contain any mutation and are functionally normal. Consistently, overexpression of exogenous A3G/A3F in CEM-T4 cells still failed to restore their anti-HIV activities. However, this activity could be restored if CEM-T4 cells were fused to 293T cells to form heterokaryons. These results demonstrate that CEM-T4 cells lack a cellular cofactor, which is critical for A3G/A3F anti-HIV activity. We propose that a further study of this novel factor will provide another strategy for a complete understanding of the A3G/A3F antiretroviral mechanism.

  15. Dispersed sites of HIV Vif-dependent polyubiquitination in the DNA deaminase APOBEC3F.

    Science.gov (United States)

    Albin, John S; Anderson, John S; Johnson, Jeffrey R; Harjes, Elena; Matsuo, Hiroshi; Krogan, Nevan J; Harris, Reuben S

    2013-04-12

    APOBEC3F (A3F) and APOBEC3G (A3G) are DNA cytosine deaminases that potently restrict human immunodeficiency virus type 1 replication when the virus is deprived of its accessory protein Vif (virion infectivity factor). Vif counteracts these restriction factors by recruiting A3F and A3G to an E3 ubiquitin (Ub) ligase complex that mediates their polyubiquitination (polyUb) and proteasomal degradation. While previous efforts have identified single amino acid residues in APOBEC3 proteins required for Vif recognition, less is known about the downstream Ub acceptor sites that are targeted. One prior report identified a cluster of polyubiquitinated residues in A3G and proposed an antiparallel model of A3G interaction with the Vif-E3 Ub ligase complex wherein Vif binding at one terminus of A3G orients the opposite terminus for polyUb [Iwatani et al. (2009). Proc. Natl. Acad. Sci. USA, 106, 19539-19544]. To test the generalizability of this model, we carried out a complete mutagenesis of the lysine residues in A3F and used a complementary, unbiased proteomic approach to identify Ub acceptor sites targeted by Vif. Our data indicate that internal lysines are the dominant Ub acceptor sites in both A3F and A3G. In contrast with the proposed antiparallel model, however, we find that the Vif-dependent polyUb of A3F and A3G can occur at multiple acceptor sites dispersed along predicted lysine-enriched surfaces of both the N- and C-terminal deaminase domains. These data suggest an alternative model for binding of APOBEC3 proteins to the Vif-E3 Ub ligase complex and diminish enthusiasm for the amenability of APOBEC3 Ub acceptor sites to therapeutic intervention.

  16. Differences in APOBEC3G expression in CD4+ T helper lymphocyte subtypes modulate HIV-1 infectivity.

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    Michael L Vetter

    2009-02-01

    Full Text Available The cytidine deaminases APOBEC3G and APOBEC3F exert anti-HIV-1 activity that is countered by the HIV-1 vif protein. Based on potential transcription factor binding sites in their putative promoters, we hypothesized that expression of APOBEC3G and APOBEC3F would vary with T helper lymphocyte differentiation. Naive CD4+ T lymphocytes were differentiated to T helper type 1 (Th1 and 2 (Th2 effector cells by expression of transcription factors Tbet and GATA3, respectively, as well as by cytokine polarization. APOBEC3G and APOBEC3F RNA levels, and APOBEC3G protein levels, were higher in Th1 than in Th2 cells. T cell receptor stimulation further increased APOBEC3G and APOBEC3F expression in Tbet- and control-transduced, but not in GATA3-transduced, cells. Neutralizing anti-interferon-gamma antibodies reduced both basal and T cell receptor-stimulated APOBEC3G and APOBEC3F expression in Tbet- and control-transduced cells. HIV-1 produced from Th1 cells had more virion APOBEC3G, and decreased infectivity, compared to virions produced from Th2 cells. These differences between Th1- and Th2-produced virions were greater for viruses lacking functional vif, but also seen with vif-positive viruses. Over-expression of APOBEC3G in Th2 cells decreased the infectivity of virions produced from Th2 cells, and reduction of APOBEC3G in Th1 cells increased infectivity of virions produced from Th1 cells, consistent with a causal role for APOBEC3G in the infectivity difference. These results indicate that APOBEC3G and APOBEC3F levels vary physiologically during CD4+ T lymphocyte differentiation, that interferon-gamma contributes to this modulation, and that this physiological regulation can cause changes in infectivity of progeny virions, even in the presence of HIV-1 vif.

  17. APOBEC3B expression in human leptomeninges and meningiomas

    Science.gov (United States)

    Johnson, Mahlon D.; Reeder, Jay E.; O'Connell, Mary

    2016-01-01

    Nucleic acid-editing enzymes of the apolipoprotein B mRNA-editing enzyme (APOBEC) family have been associated with somatic mutation in cancer. However, the role of APOBEC catalytic subunit 3B (APOBEC3B) editing in the pathogenesis of base substitutions in meningiomas is unknown. In the present study, the expression of APOBEC3B was examined by reverse transcription-quantitative polymerase chain reaction (RT-qPCR) and western blot analyses in five fetal and one adult human leptomeninges and 38 meningiomas. Genomic DNA was sequenced using the Illumina Tru-Seq Cancer Panel. Three meningioma primary cultures were also established and treated with cerebrospinal fluid form patients without neurological disease or platelet-derived growth factor-BB (PDGF-BB), prior to evaluation of APOBEC3B expression. By western blotting, APOBEC3B was revealed to be present in 100% of the fetal leptomeninges, and in 88% of World Health Organization grade I, 100% of grade II and 83% of grade III meningiomas tested, but was not different between grades. RT-qPCR revealed no difference in the mRNA expression of APOBEC3B between grades. Sequencing revealed no elevated levels of the C>T mutations that are characteristic of APOBEC3B editing of genomic DNA. Treatment with cerebrospinal fluid and PDGF-BB had no effect on APOBEC3B protein expression in the leptomeningeal or meningioma cells. These findings suggest that the mutations associated with increased APOBEC3B expression may not be central to the pathogenesis of meningiomas. PMID:28101245

  18. APOBEC3G expression is correlated with poor prognosis in colon carcinoma patients with hepatic metastasis.

    Science.gov (United States)

    Lan, Huanrong; Jin, Ketao; Gan, Meifu; Wen, Shouxiang; Bi, Tienan; Zhou, Shenkang; Zhu, Naibiao; Teng, Lisong; Yu, Wenjie

    2014-01-01

    Increased expression of apolipoprotein B mRNA-editing enzyme catalytic polypeptide-like 3G (APOBEC3G) in human primary colorectal tumors and hepatic metastasis has been detected. However, the clinical relevance of APOBEC3G in colon carcinoma hepatic metastasis remains uncertain. The aim of this study was to assess the prognostic value of APOBEC3G in colon carcinoma patients with hepatic metastasis after hepatic resection. APOBEC3G expression was evaluated by immunohistochemistry in paraffin-embedded primary colon carcinoma and paired hepatic metastasis tissues from 136 patients with liver metastasis from colon carcinoma that underwent hepatic resection. The relation between APOBEC3G expression and clinicopathologic factors and long-term prognosis in these 136 patients was retrospectively examined. The prognostic significance of negative or positive APOBEC3G expression in colon carcinoma hepatic metastasis was assessed using Kaplan-Meier survival analysis and log-rank tests. Positive expression of APOBEC3G was correlated with liver metastasis of colon cancer. Univariate analysis indicated significantly worse overall survival (OS) for patients with a positive APOBEC3G expression in colon carcinoma hepatic metastasis than for patients with a negative APOBEC3G expression. Multivariate analysis showed positive-APOBEC3G in colon carcinoma hepatic metastasis to be an independent prognostic factor for OS after hepatic resection (P = 0.000). Positive expression of APOBEC3G was statistically significantly associated with poor prognosis of colon carcinoma patients with hepatic metastasis. APOBEC3G could be a novel predictor for poor prognosis of colon carcinoma patients with hepatic metastasis after hepatic resection.

  19. Natural polymorphisms in human APOBEC3H and HIV-1 Vif combine in primary T lymphocytes to affect viral G-to-A mutation levels and infectivity.

    Science.gov (United States)

    Refsland, Eric W; Hultquist, Judd F; Luengas, Elizabeth M; Ikeda, Terumasa; Shaban, Nadine M; Law, Emily K; Brown, William L; Reilly, Cavan; Emerman, Michael; Harris, Reuben S

    2014-11-01

    The Vif protein of HIV-1 allows virus replication by degrading several members of the host-encoded APOBEC3 family of DNA cytosine deaminases. Polymorphisms in both host APOBEC3 genes and the viral vif gene have the potential to impact the extent of virus replication among individuals. The most genetically diverse of the seven human APOBEC3 genes is APOBEC3H with seven known haplotypes. Overexpression studies have shown that a subset of these variants express stable and active proteins, whereas the others encode proteins with a short half-life and little, if any, antiviral activity. We demonstrate that these stable/unstable phenotypes are an intrinsic property of endogenous APOBEC3H proteins in primary CD4+ T lymphocytes and confer differential resistance to HIV-1 infection in a manner that depends on natural variation in the Vif protein of the infecting virus. HIV-1 with a Vif protein hypo-functional for APOBEC3H degradation, yet fully able to counteract APOBEC3D, APOBEC3F, and APOBEC3G, was susceptible to restriction and hypermutation in stable APOBEC3H expressing lymphocytes, but not in unstable APOBEC3H expressing lymphocytes. In contrast, HIV-1 with hyper-functional Vif counteracted stable APOBEC3H proteins as well as all other endogenous APOBEC3s and replicated to high levels. We also found that APOBEC3H protein levels are induced over 10-fold by infection. Finally, we found that the global distribution of stable/unstable APOBEC3H haplotypes correlates with the distribution a critical hyper/hypo-functional Vif amino acid residue. These data combine to strongly suggest that stable APOBEC3H haplotypes present as in vivo barriers to HIV-1 replication, that Vif is capable of adapting to these restrictive pressures, and that an evolutionary equilibrium has yet to be reached.

  20. Natural polymorphisms in human APOBEC3H and HIV-1 Vif combine in primary T lymphocytes to affect viral G-to-A mutation levels and infectivity.

    Directory of Open Access Journals (Sweden)

    Eric W Refsland

    2014-11-01

    Full Text Available The Vif protein of HIV-1 allows virus replication by degrading several members of the host-encoded APOBEC3 family of DNA cytosine deaminases. Polymorphisms in both host APOBEC3 genes and the viral vif gene have the potential to impact the extent of virus replication among individuals. The most genetically diverse of the seven human APOBEC3 genes is APOBEC3H with seven known haplotypes. Overexpression studies have shown that a subset of these variants express stable and active proteins, whereas the others encode proteins with a short half-life and little, if any, antiviral activity. We demonstrate that these stable/unstable phenotypes are an intrinsic property of endogenous APOBEC3H proteins in primary CD4+ T lymphocytes and confer differential resistance to HIV-1 infection in a manner that depends on natural variation in the Vif protein of the infecting virus. HIV-1 with a Vif protein hypo-functional for APOBEC3H degradation, yet fully able to counteract APOBEC3D, APOBEC3F, and APOBEC3G, was susceptible to restriction and hypermutation in stable APOBEC3H expressing lymphocytes, but not in unstable APOBEC3H expressing lymphocytes. In contrast, HIV-1 with hyper-functional Vif counteracted stable APOBEC3H proteins as well as all other endogenous APOBEC3s and replicated to high levels. We also found that APOBEC3H protein levels are induced over 10-fold by infection. Finally, we found that the global distribution of stable/unstable APOBEC3H haplotypes correlates with the distribution a critical hyper/hypo-functional Vif amino acid residue. These data combine to strongly suggest that stable APOBEC3H haplotypes present as in vivo barriers to HIV-1 replication, that Vif is capable of adapting to these restrictive pressures, and that an evolutionary equilibrium has yet to be reached.

  1. Identification of Specific Determinants of Human APOBEC3F, APOBEC3C, and APOBEC3DE and African Green Monkey APOBEC3F That Interact with HIV-1 Vif ▿

    OpenAIRE

    Smith, Jessica L.; Pathak, Vinay K.

    2010-01-01

    Human APOBEC3F (hA3F) and human APOBEC3G (hA3G) are potent anti-human immunodeficiency virus (anti-HIV) host factors that suppress viral replication by hypermutating the viral genome, inhibiting reverse transcription, and hindering integration. To overcome hA3F and hA3G, HIV-1 encodes Vif, which binds and targets these host proteins for proteasomal degradation. Previously, we reported that the hA3F-Vif interactions that lead to hA3F degradation are located in the region comprising amino acids...

  2. The APOBEC3C crystal structure and the interface for HIV-1 Vif binding.

    Science.gov (United States)

    Kitamura, Shingo; Ode, Hirotaka; Nakashima, Masaaki; Imahashi, Mayumi; Naganawa, Yuriko; Kurosawa, Teppei; Yokomaku, Yoshiyuki; Yamane, Takashi; Watanabe, Nobuhisa; Suzuki, Atsuo; Sugiura, Wataru; Iwatani, Yasumasa

    2012-10-01

    The human apolipoprotein B mRNA-editing enzyme catalytic polypeptide-like 3 (APOBEC3, referred to as A3) proteins are cellular cytidine deaminases that potently restrict retrovirus replication. However, HIV-1 viral infectivity factor (Vif) counteracts the antiviral activity of most A3 proteins by targeting them for proteasomal degradation. To date, the structure of an A3 protein containing a Vif-binding interface has not been solved. Here, we report a high-resolution crystal structure of APOBEC3C and identify the HIV-1 Vif-interaction interface. Extensive structure-guided mutagenesis revealed the role of a shallow cavity composed of hydrophobic or negatively charged residues between the α2 and α3 helices. This region is distant from the DPD motif (residues 128-130) of APOBEC3G that participates in HIV-1 Vif interaction. These findings provide insight into Vif-A3 interactions and could lead to the development of new pharmacologic anti-HIV-1 compounds.

  3. DNA Mutagenic Activity and Capacity for HIV-1 Restriction of the Cytidine Deaminase APOBEC3G Depends on Whether DNA or RNA Binds to Tyrosine 315.

    Science.gov (United States)

    Polevoda, Bogdan; Joseph, Rebecca; Friedman, Alan E; Bennett, Ryan P; Greiner, Rebecca; De Zoysa, Thareendra; Stewart, Ryan A; Smith, Harold C

    2017-04-05

    APOBEC3G (A3G) belongs to the AID/APOBEC protein family of cytidine deaminases (CDA) that bind to nucleic acids. A3G mutates the HIV genome by deamination of dC to dU, leading to accumulation of virus-inactivating mutations. Binding to cellular RNAs inhibits A3G binding to substrate single-stranded (ss) DNA and CDA activity. RNA and ssDNA bind to the same three A3G tryptic peptides (amino acids 181-194, 314-320, and 345-374) that form parts of a continuously exposed protein surface extending from the catalytic domain in the C-terminus of A3G to its N-terminus. We show here that the A3G tyrosines 181 and 315 directly cross-link ssDNA. Binding experiments showed that a Y315A mutation alone significantly reduced A3G binding to both ssDNA and RNA, whereas Y181A and Y182A mutations only moderately affected A3G nucleic acid binding. Consistent with these findings, the Y315A mutant exhibited little to no deaminase activity in an E. coli DNA mutator reporter, while Y181A and Y182A mutants retained ~50% of wild-type A3G activity. The Y315A mutant also showed a markedly reduced ability to assemble into viral particles and had reduced antiviral activity. In uninfected cells, the impaired RNA-binding capacity of Y315A was evident by a shift of A3G from high-molecular-mass ribonucleoprotein complexes to low-molecular-mass complexes. We conclude that Y315 is essential for coordinating ssDNA interaction with or entry to the deaminase domain and hypothesize that RNA bound to Y315 may be sufficient to competitively inhibit ssDNA deaminase-dependent antiviral activity.

  4. Progressive APOBEC3B mRNA expression in distant breast cancer metastases

    Science.gov (United States)

    Dalm, Simone U.; de Weerd, Vanja; Moelans, Cathy B.; ter Hoeve, Natalie; van Diest, Paul J.; Martens, John W. M.; van Deurzen, Carolien H. M.

    2017-01-01

    Background APOBEC3B was recently identified as a gain-of-function enzymatic source of mutagenesis, which may offer novel therapeutic options with molecules that specifically target this enzyme. In primary breast cancer, APOBEC3B mRNA is deregulated in a substantial proportion of cases and its expression is associated with poor prognosis. However, its expression in breast cancer metastases, which are the main causes of breast cancer-related death, remained to be elucidated. Patients and methods RNA was isolated from 55 primary breast cancers and paired metastases, including regional lymph node (N = 20) and distant metastases (N = 35). APOBEC3B mRNA levels were measured by RT-qPCR. Expression levels of the primary tumors and corresponding metastases were compared, including subgroup analysis by estrogen receptor (ER/ESR1) status. Results Overall, APOBEC3B mRNA levels of distant metastases were significantly higher as compared to the corresponding primary breast tumor (P = 0.0015), an effect that was not seen for loco-regional lymph node metastases (P = 0.23). Subgroup analysis by ER-status showed that increased APOBEC3B levels in distant metastases were restricted to metastases arising from ER-positive primary breast cancers (P = 0.002). However, regarding ER-negative primary tumors, only loco-regional lymph node metastases showed increased APOBEC3B expression when compared to the corresponding primary tumor (P = 0.028). Conclusion APOBEC3B mRNA levels are significantly higher in breast cancer metastases as compared to the corresponding ER-positive primary tumors. This suggests a potential role for APOBEC3B in luminal breast cancer progression, and consequently, a promising role for anti-APOBEC3B therapies in advanced stages of this frequent form of breast cancer. PMID:28141868

  5. Identification of HIV-1 Vif regions required for CBF-β interaction and APOBEC3 suppression.

    Science.gov (United States)

    Wang, Hong; Liu, Bin; Liu, Xin; Li, Zhaolong; Yu, Xiao-Fang; Zhang, Wenyan

    2014-01-01

    Human immunodeficiency virus type 1 (HIV-1) Vif requires core binding factor β (CBF-β) to degrade the host APOBEC3 restriction factors. Although a minimum domain and certain amino acids of HIV-1 Vif, including hydrophobic residues at the N-terminal, have been identified as critical sites for binding with CBF-β, other regions that potentially mediate this interaction need to be further investigated. Here, we mapped two new regions of HIV-1 Vif that are required for interaction with CBF-β by generating a series of single-site or multiple-site Vif mutants and testing their effect on the suppression of APOBEC3G (A3G) and APOBEC3F (A3F). A number of the mutants, including G84A/SIEW86-89AAAA (84/86-89), E88A/W89A (88/89), G84A, W89A, L106S and I107S in the 84GxSIEW89 and L102ADQLI107 regions, affected Vif function by disrupting CBF-β binding. These Vif mutants also had altered interactions with CUL5, since CBF-β is known to facilitate the binding of Vif to CUL5. We further showed that this effect was not due to misfolding or conformational changes in Vif, as the mutants still maintained their interactions with other factors such as ElonginB, A3G and A3F. Notably, G84D and D104A had stronger effects on the Vif-CUL5 interaction than on the Vif-CBF-β interaction, indicating that they mainly influenced the CUL5 interaction and implying that the interaction of Vif with CUL5 contributes to the binding of Vif to CBF-β. These new binding interfaces with CBF-β in HIV-1 Vif provide novel targets for the development of HIV-1 inhibitors.

  6. Crystal structure of the anti-viral APOBEC3G catalytic domain and functional implications

    Energy Technology Data Exchange (ETDEWEB)

    Holden, Lauren G.; Prochnow, Courtney; Chang, Y. Paul; Bransteitter, Ronda; Chelico, Linda; Sen, Udayaditya; Stevens, Raymond C.; Goodman, Myron F.; Chen, Xiaojiang S. (USC); (Scripps)

    2009-04-07

    The APOBEC family members are involved in diverse biological functions. APOBEC3G restricts the replication of human immunodeficiency virus (HIV), hepatitis B virus and retroelements by cytidine deamination on single-stranded DNA or by RNA binding. Here we report the high-resolution crystal structure of the carboxy-terminal deaminase domain of APOBEC3G (APOBEC3G-CD2) purified from Escherichia coli. The APOBEC3G-CD2 structure has a five-stranded {beta}-sheet core that is common to all known deaminase structures and closely resembles the structure of another APOBEC protein, APOBEC2. A comparison of APOBEC3G-CD2 with other deaminase structures shows a structural conservation of the active-site loops that are directly involved in substrate binding. In the X-ray structure, these APOBEC3G active-site loops form a continuous 'substrate groove' around the active centre. The orientation of this putative substrate groove differs markedly (by 90 degrees) from the groove predicted by the NMR structure. We have introduced mutations around the groove, and have identified residues involved in substrate specificity, single-stranded DNA binding and deaminase activity. These results provide a basis for understanding the underlying mechanisms of substrate specificity for the APOBEC family.

  7. APOBEC3G inhibits elongation of HIV-1 reverse transcripts.

    Directory of Open Access Journals (Sweden)

    Kate N Bishop

    2008-12-01

    Full Text Available APOBEC3G (A3G is a host cytidine deaminase that, in the absence of Vif, restricts HIV-1 replication and reduces the amount of viral DNA that accumulates in cells. Initial studies determined that A3G induces extensive mutation of nascent HIV-1 cDNA during reverse transcription. It has been proposed that this triggers the degradation of the viral DNA, but there is now mounting evidence that this mechanism may not be correct. Here, we use a natural endogenous reverse transcriptase assay to show that, in cell-free virus particles, A3G is able to inhibit HIV-1 cDNA accumulation not only in the absence of hypermutation but also without the apparent need for any target cell factors. We find that although reverse transcription initiates in the presence of A3G, elongation of the cDNA product is impeded. These data support the model that A3G reduces HIV-1 cDNA levels by inhibiting synthesis rather than by inducing degradation.

  8. APOBEC3G与Vif在HIV-1感染中的作用%The Roles of APOBEC3G and Vif in HIV-1 Infections

    Institute of Scientific and Technical Information of China (English)

    马寅佳; 杨怡姝; 曾毅

    2012-01-01

    Apolipoprotein B mRNA-editing catalytic polypeptide-like (APOBEC) proteins are cytidine deaminases that exert antiviral activity to inhibit the infection of many viruses, especially retrovintses. The antiviral activity of AP0BEC-3G( A3G) and APOBEC-3F are stronger than other family members. A3G inhibits human immunodeficiency virus (HIV) infection through cytidine deamination and non-cytidine deamination. However, the degradation of A3G by the ubiquitin- proteasome system can be antagonized by HIV-1 viral infectivity factor (Vif). The study of the interaction of A3G and Vif will be informative for its connection with HIV-1 treatments.%载脂蛋白B mRNA编辑催化多肽样(apolipoprotein B mRNA-editing catalytic polypeptide-like,APOBEC)蛋白是一组胞嘧啶脱氨基酶,具有天然的抗病毒活性,对多种病毒具有抑制作用,特别是逆转录病毒.APOBEC3蛋白能够抑制人类免疫缺陷病毒(HIV-1)的感染,其中APOBEC3G和APOBEC3F的作用最强.APOBEC3G能够通过胞嘧啶脱氨基作用和非胞嘧啶脱氨基作用抑制病毒感染.HIV-1病毒感染因子(Vif)蛋白主要经泛素-蛋白酶体途径介导APOBEC3G降解,从而拮抗其抗病毒作用.APOBEC3G和Vif之间相互作用的研究对于寻求新的抗HIV治疗靶点具有重要意义.

  9. APOBEC3G is a single-stranded DNA cytidine deaminase and functions independently of HIV reverse transcriptase

    Science.gov (United States)

    Suspène, Rodolphe; Sommer, Peter; Henry, Michel; Ferris, Stéphane; Guétard, Denise; Pochet, Sylvie; Chester, Ann; Navaratnam, Naveenan; Wain-Hobson, Simon; Vartanian, Jean-Pierre

    2004-01-01

    In the absence of the viral vif gene, human immunodeficiency virus (HIV) may be restricted by the APOBEC3G gene on chromosome 22. The role of the HIV Vif protein is to exclude host cell APOBEC3G from the budding virion. As APOBEC3G shows sequence homology to cytidine deaminases, it is presumed that in the absence of Vif, cytidine residues in the cDNA are deaminated yielding uracil. It is not known if additional proteins mediate APOBEC3G function or if deamination occurs in concert with reverse transcription. This report describes an in vitro assay showing that Baculovirus derived APOBEC3G alone extensively deaminates cDNA independently of reverse transcriptase. It reproduces the dinucleotide context typical of G → A hypermutants derived from a Δvif virus. By using an RNaseH– form of reverse transcriptase, it was shown that the cDNA has to be free of its RNA template to allow deamination. APOBEC3G deamination of dC or dCTP was not detected. In short, APOBEC3G is a single-stranded DNA cytidine deaminase capable of restricting retroviral replication. PMID:15121899

  10. HIV-1 Vif Protein Mediates the Degradation of APOBEC3G in Fission Yeast When Over-expressed Using Codon Optimization

    Institute of Scientific and Technical Information of China (English)

    Lin LI; Jing-yun LI; Hong-shuai SUI; Richard Y. Zhao; Yong-jian LIU; Zuo-yi BAO; Si-yang LIU; Dao-min ZHUANG

    2008-01-01

    Interaction between the HIV-1 Vif protein and the cellular host APOBEC3G protein is a promising target for inhibition of HIV-1 replication. Considering that human cells are a very complicated environment for the study of protein interactions, the goal of this study was to check whether fission yeast could be used as a model cell for studying the Vif-APOBEC3G interaction. Vif and APOBEC3G were expressed in fusion with GFP protein in the S. pombe SP223 strain. Subcellular localizations of Vif and APOBEC3G were observed with fluorescent microscopy. Codon optimization was used to over express the Vif protein in S. pombe cells. The degradation of APOBEC3G mediated by Vif was tested through expressing Vif and GFP-APOBEC3G proteins in the same cell. Western Blot analysis was used to measure the corresponding protein levels under different experimental conditions. The results showed that the Vif protein was predominantly localized in the nucleus of S.pombe cells, APOBEC3G was localized in the cytoplasm and concentrated at punctate bodies that were often in close proximity to the nucleus but were not necessarily restricted from other regions in the cytoplasm. Vif protein expression levels were increased significantly by using codon optimization and APOBEC3G was degraded when Vif was over-expressed in the same S. pombe cells. These results indicate that fission yeast is a good model for studying the interaction between the Vif and APOBEC3G proteins.

  11. Incorporation of mouse APOBEC3 into murine leukemia virus virions decreases the activity and fidelity of reverse transcriptase.

    Science.gov (United States)

    Boi, Stefano; Kolokithas, Angelo; Shepard, Joyce; Linwood, Rebecca; Rosenke, Kyle; Van Dis, Erik; Malik, Frank; Evans, Leonard H

    2014-07-01

    APOBEC3 proteins are restriction factors that induce G→A hypermutation in retroviruses during replication as a result of cytidine deamination of minus-strand DNA transcripts. However, the mechanism of APOBEC inhibition of murine leukemia viruses (MuLVs) does not appear to be G→A hypermutation and is unclear. In this report, the incorporation of mA3 in virions resulted in a loss in virion reverse transcriptase (RT) activity and RT fidelity that correlated with the loss of virion-specific infectivity.

  12. APOBEC3G oligomerization is associated with the inhibition of both Alu and LINE-1 retrotransposition.

    Directory of Open Access Journals (Sweden)

    Takayoshi Koyama

    Full Text Available Alu and LINE-1 (L1, which constitute ~11% and ~17% of the human genome, respectively, are transposable non-LTR retroelements. They transpose not only in germ cells but also in somatic cells, occasionally causing cancer. We have previously demonstrated that antiretroviral restriction factors, human APOBEC3 (hA3 proteins (A-H, differentially inhibit L1 retrotransposition. In this present study, we found that hA3 members also restrict Alu retrotransposition at differential levels that correlate with those observed previously for L1 inhibition. Through deletion analyses based on the best-characterized hA3 member human APOBEC3G (hA3G, its N-terminal 30 amino acids were required for its inhibitory activity against Alu retrotransposition. The inhibitory effect of hA3G on Alu retrotransposition was associated with its oligomerization that was affected by the deletion of its N-terminal 30 amino acids. Through structural modeling, the amino acids 24 to 28 of hA3G were predicted to be located at the interface of the dimer. The mutation of these residues resulted in abrogated hA3G oligomerization, and consistently abolished the inhibitory activity of hA3G against Alu retrotransposition. Importantly, the anti-L1 activity of hA3G was also associated with hA3G oligomerization. These results suggest that the inhibitory activities of hA3G against Alu and L1 retrotransposition might involve a common mechanism.

  13. Cell-specific Regulation of APOBEC3F by Interferons

    Institute of Scientific and Technical Information of China (English)

    Songcheng YING; Xuzhao ZHANG; Phuong Thi Nguyen SARKIS; Rongzhen XU; Xiaofang YU

    2007-01-01

    Human cytidine deaminase APOBEC3F (A3F) has broad anti-viral activity against hepatitis B virus and retroviruses including human immunodeficiency virus type 1. However, its regulation in viral natural target cells such CD4+ T lymphocytes, macrophages, and primary liver cells has not been well studied. Here we showed that A3F was up-regulated by interferon (IFN)-α in primary hepatocytes and multiple liver cell lines as well as macrophages. Although the IFN-α signaling pathway was active in T lymphoid cells and induction of other IFN stimulated genes such as PKR was detected, A3F and APOBEC3G (A3G) were not induced by IFN-o in these cells. Thus, additional factors other than known IFN-stimulated genes also regulated IFN-α-induced A3F expression distinctly. A3F and A3G expression levels in primary hepatocytes, especially after IFN-α stimulation, were comparable to those in CD4+ T lymphocytes in some individuals. Significant variations of A3F and A3G expression in primary hepatocytes from various subjects were observed. Individual variations in A3F and/or A3G regulation and expression might influence the clinical outcomes of hepatitis B infection.

  14. The Structural Interface between HIV-1 Vif and Human APOBEC3H.

    Science.gov (United States)

    Ooms, Marcel; Letko, Michael; Simon, Viviana

    2017-03-01

    Human APOBEC3H (A3H) is a cytidine deaminase that inhibits HIV-1 replication. To evade this restriction, the HIV-1 Vif protein binds A3H and mediates its proteasomal degradation. To date, little information on the Vif-A3H interface has been available. To decipher how both proteins interact, we first mapped the Vif-binding site on A3H by functionally testing a large set of A3H mutants in single-cycle infectivity and replication assays. Our data show that the two A3H α-helixes α3 and α4 represent the Vif-binding site of A3H. We next used viral adaptation and a set of Vif mutants to identify novel, reciprocal Vif variants that rescued viral infectivity in the presence of two Vif-resistant A3H mutants. These A3H-Vif interaction points were used to generate the first A3H-Vif structure model, which revealed that the A3H helixes α3 and α4 interact with the Vif β-sheet (β2-β5). This model is in good agreement with previously reported Vif and A3H amino acids important for interaction. Based on the predicted A3H-Vif interface, we tested additional points of contact, which validated our model. Moreover, these experiments showed that the A3H and A3G binding sites on HIV-1 Vif are largely distinct, with both host proteins interacting with Vif β-strand 2. Taken together, this virus-host interface model explains previously reported data and will help to identify novel drug targets to combat HIV-1 infection.IMPORTANCE HIV-1 needs to overcome several intracellular restriction factors in order to replicate efficiently. The human APOBEC3 locus encodes seven proteins, of which A3D, A3F, A3G, and A3H restrict HIV-1. HIV encodes the Vif protein, which binds to the APOBEC3 proteins and leads to their proteasomal degradation. No HIV-1 Vif-APOBEC3 costructure exists to date despite extensive research. We and others previously generated HIV-1 Vif costructure models with A3G and A3F by mapping specific contact points between both proteins. Here, we applied a similar approach to HIV

  15. Small ruminant lentiviral Vif proteins commonly utilize cyclophilin A, an evolutionarily and structurally conserved protein, to degrade ovine and caprine APOBEC3 proteins.

    Science.gov (United States)

    Yoshikawa, Rokusuke; Izumi, Taisuke; Nakano, Yusuke; Yamada, Eri; Moriwaki, Miyu; Misawa, Naoko; Ren, Fengrong; Kobayashi, Tomoko; Koyanagi, Yoshio; Sato, Kei

    2016-06-01

    Mammals have co-evolved with retroviruses, including lentiviruses, over a long period. Evidence supporting this contention is that viral infectivity factor (Vif) encoded by lentiviruses antagonizes the anti-viral action of cellular apolipoprotein B mRNA editing enzyme catalytic polypeptide-like 3 (APOBEC3) of the host. To orchestrate E3 ubiquitin ligase complex for APOBEC3 degradation, Vifs utilize mammalian proteins such as core-binding factor beta (CBFB; for primate lentiviruses) or cyclophilin A (CYPA; for Maedi-Visna virus [MVV]). However, the co-evolutionary relationship between lentiviral Vif and the mammalian proteins associated with Vif-mediated APOBEC3 degradation is poorly understood. Moreover, it is unclear whether Vif proteins of small ruminant lentiviruses (SRLVs), including MVV and caprine arthritis encephalitis virus (CAEV), commonly utilize CYPA to degrade the APOBEC3 of their hosts. In this study, molecular phylogenetic and protein homology modeling revealed that Vif co-factors are evolutionarily and structurally conserved. It was also found that not only MVV but also CAEV Vifs degrade APOBEC3 of both sheep and goats and that CAEV Vifs interact with CYPA. These findings suggest that lentiviral Vifs chose evolutionarily and structurally stable proteins as their partners (e.g., CBFB or CYPA) for APOBEC3 degradation and, particularly, that SRLV Vifs evolved to utilize CYPA as their co-factor in degradation of ovine and caprine APOBEC3.

  16. APOBEC3 proteins can copackage and comutate HIV-1 genomes

    OpenAIRE

    Desimmie, Belete A.; Burdick, Ryan C.; Izumi, Taisuke; Doi, Hibiki; Shao, Wei; Alvord, W. Gregory; Sato, Kei; Koyanagi, Yoshio; Jones, Sara; Wilson, Eleanor; Hill, Shawn; Maldarelli, Frank; Hu, Wei-Shau; Pathak, Vinay K.

    2016-01-01

    Although APOBEC3 cytidine deaminases A3G, A3F, A3D and A3H are packaged into virions and inhibit viral replication by inducing G-to-A hypermutation, it is not known whether they are copackaged and whether they can act additively or synergistically to inhibit HIV-1 replication. Here, we showed that APOBEC3 proteins can be copackaged by visualization of fluorescently-tagged APOBEC3 proteins using single-virion fluorescence microscopy. We further determined that viruses produced in the presence ...

  17. Differential requirements for HIV-1 Vif-mediated APOBEC3G degradation and RUNX1-mediated transcription by core binding factor beta.

    Science.gov (United States)

    Du, Juan; Zhao, Ke; Rui, Yajuan; Li, Peng; Zhou, Xiaohong; Zhang, Wenyan; Yu, Xiao-Fang

    2013-02-01

    Core binding factor beta (CBFβ), a transcription regulator through RUNX binding, was recently reported critical for Vif function. Here, we mapped the primary functional domain important for Vif function to amino acids 15 to 126 of CBFβ. We also revealed that different lengths and regions are required for CBFβ to assist Vif or RUNX. The important interaction domains that are uniquely required for Vif but not RUNX function represent novel targets for the development of HIV inhibitors.

  18. APOBEC3 Interference during Replication of Viral Genomes

    Directory of Open Access Journals (Sweden)

    Luc Willems

    2015-06-01

    Full Text Available Co-evolution of viruses and their hosts has reached a fragile and dynamic equilibrium that allows viral persistence, replication and transmission. In response, infected hosts have developed strategies of defense that counteract the deleterious effects of viral infections. In particular, single-strand DNA editing by Apolipoprotein B Editing Catalytic subunits proteins 3 (APOBEC3s is a well-conserved mechanism of mammalian innate immunity that mutates and inactivates viral genomes. In this review, we describe the mechanisms of APOBEC3 editing during viral replication, the viral strategies that prevent APOBEC3 activity and the consequences of APOBEC3 modulation on viral fitness and host genome integrity. Understanding the mechanisms involved reveals new prospects for therapeutic intervention.

  19. Reassessing APOBEC3G Inhibition by HIV-1 Vif-Derived Peptides.

    Science.gov (United States)

    Richards, Christopher M; Li, Ming; Perkins, Angela L; Rathore, Anurag; Harki, Daniel A; Harris, Reuben S

    2017-01-06

    The human APOBEC3G (A3G) enzyme restricts HIV-1 in the absence of the viral accessory protein viral infectivity factor (Vif) by deaminating viral cDNA cytosines to uracils. These uracil lesions base-pair with adenines during the completion of reverse transcription and result in A3G signature G-to-A mutations in the viral genome. Vif protects HIV-1 from A3G-mediated restriction by forming an E3-ubiquitin ligase complex to polyubiquitinate A3G and trigger its degradation. Prior studies indicated that Vif may also directly block the enzymatic activity of A3G and, provocatively, that Vif-derived peptides, Vif 25-39 and Vif 105-119, are similarly inhibitory. Here, we show that Vif 25-39 does not inhibit A3G enzymatic activity and that the inhibitory effect of Vif 105-119 and that of a shorter derivative Vif 107-115, although recapitulated, are non-specific. We also elaborate a simple method for assaying DNA cytosine deaminase activity that eliminates potential polymerase chain reaction-induced biases. Our results show that these Vif-derived peptides are unlikely to be useful as tools to study A3G function or as leads for the development of future therapeutics.

  20. Structure of the Vif-binding domain of the antiviral enzyme APOBEC3G.

    Science.gov (United States)

    Kouno, Takahide; Luengas, Elizabeth M; Shigematsu, Megumi; Shandilya, Shivender M D; Zhang, JingYing; Chen, Luan; Hara, Mayuko; Schiffer, Celia A; Harris, Reuben S; Matsuo, Hiroshi

    2015-06-01

    The human APOBEC3G (A3G) DNA cytosine deaminase restricts and hypermutates DNA-based parasites including HIV-1. The viral infectivity factor (Vif) prevents restriction by triggering A3G degradation. Although the structure of the A3G catalytic domain is known, the structure of the N-terminal Vif-binding domain has proven more elusive. Here, we used evolution- and structure-guided mutagenesis to solubilize the Vif-binding domain of A3G, thus permitting structural determination by NMR spectroscopy. A smaller zinc-coordinating pocket and altered helical packing distinguish the structure from previous catalytic-domain structures and help to explain the reported inactivity of this domain. This soluble A3G N-terminal domain is bound by Vif; this enabled mutagenesis and biochemical experiments, which identified a unique Vif-interacting surface formed by the α1-β1, β2-α2 and β4-α4 loops. This structure sheds new light on the Vif-A3G interaction and provides critical information for future drug development.

  1. Human APOBEC3G drives HIV-1 evolution and the development of drug resistance

    Energy Technology Data Exchange (ETDEWEB)

    Bhattacharya, Tamoy [Los Alamos National Laboratory; Kim, Eun - Young [FEINBERG SCHOOL OF MEDS; Koning, Fransje [KING' S COLLEGE LONDON; Malim, Michael [KING' S COLLEGE LONDON; Wolinsky, Steven M [FEINBERG SCHOOL OF MEDS

    2008-01-01

    Human APOBEC3G (hA3G) is an innate virus restriction factor that induces deamination of specific cytidine residues in single-stranded human immunodeficiency virus type 1 (HIV-1) DNA. Whereas destructive hA3G editing leads to a profound loss of HIV-1 infectivity, more limited editing could be a source of adaptation and diversification. Here we show that the presence of hA3G in T-cells can drive the development of diversity in HIV-1 populations and that under selection pressure imposed by the nucleotide analog reverse transcriptase inhibitor 3TC ((-)2',3'-dideoxy-3'-thiacytidine), a single point mutation that confers 3TC resistance, methionine 184 to isoleucine (M1841), emerges rapidly and reaches fixation. These results provide strong evidence that mutation by hA3G is an important source of genetic variation on which natural selection acts to shape the structure of the viral population and drive the tempo of HIV-1 evolution.

  2. An analog of camptothecin inactive against Topoisomerase I is broadly neutralizing of HIV-1 through inhibition of Vif-dependent APOBEC3G degradation.

    Science.gov (United States)

    Bennett, Ryan P; Stewart, Ryan A; Hogan, Priscilla A; Ptak, Roger G; Mankowski, Marie K; Hartman, Tracy L; Buckheit, Robert W; Snyder, Beth A; Salter, Jason D; Morales, Guillermo A; Smith, Harold C

    2016-12-01

    Camptothecin (CPT) is a natural product discovered to be active against various cancers through its ability to inhibit Topoisomerase I (TOP1). CPT analogs also have anti-HIV-1 (HIV) activity that was previously shown to be independent of TOP1 inhibition. We show that a cancer inactive CPT analog (O2-16) inhibits HIV infection by disrupting multimerization of the HIV protein Vif. Antiviral activity depended on the expression of the cellular viral restriction factor APOBEC3G (A3G) that, in the absence of functional Vif, has the ability to hypermutate HIV proviral DNA during reverse transcription. Our studies demonstrate that O2-16 has low cytotoxicity and inhibits Vif-dependent A3G degradation, enabling A3G packaging into HIV viral particles that results in A3G signature hypermutations in viral genomes. This antiviral activity was A3G-dependent and broadly neutralizing against sixteen HIV clinical isolates from groups M (subtypes A-G), N, and O as well as seven single and multi-drug resistant strains of HIV. Molecular modeling predicted binding near the PPLP motif crucial for Vif multimerization and activity. O2-16 also was active in blocking Vif degradation of APOBEC3F (A3F). We propose that CPT analogs not active against TOP1 have novel therapeutic potential as Vif antagonists that enable A3G-dependent hypermutation of HIV.

  3. Elevated APOBEC3B Correlates with Poor Outcomes for Estrogen-Receptor-Positive Breast Cancers

    NARCIS (Netherlands)

    A.M. Sieuwerts (Anieta); S. Willis (Scooter); M.J. Burns (Michael); M.P. Look (Maxime); M.E.M.-V. Gelder (Marion E. Meijer-Van); A. Schlicker (Andreas); D.A.M. Heideman (Danielle); H. Jacobs (Heinz); L. Wessels (Lodewyk); B. Leyland-Jones (Brian); K.P. Gray (Kathryn); J.A. Foekens (John); R.S. Harris (Reuben); J.W.M. Martens (John)

    2014-01-01

    textabstractRecent observations connected DNA cytosine deaminase APOBEC3B to the genetic evolution of breast cancer. We addressed whether APOBEC3B is associated with breast cancer clinical outcomes. APOBEC3B messenger RNA (mRNA) levels were related in 1,491 primary breast cancers to disease-free (DF

  4. A whole genome screen for HIV restriction factors

    Directory of Open Access Journals (Sweden)

    Liu Li

    2011-11-01

    Full Text Available Abstract Background Upon cellular entry retroviruses must avoid innate restriction factors produced by the host cell. For human immunodeficiency virus (HIV human restriction factors, APOBEC3 (apolipoprotein-B-mRNA-editing-enzyme, p21 and tetherin are well characterised. Results To identify intrinsic resistance factors to HIV-1 replication we screened 19,121 human genes and identified 114 factors with significant inhibition of infection. Those with a known function are involved in a broad spectrum of cellular processes including receptor signalling, vesicle trafficking, transcription, apoptosis, cross-nuclear membrane transport, meiosis, DNA damage repair, ubiquitination and RNA processing. We focused on the PAF1 complex which has been previously implicated in gene transcription, cell cycle control and mRNA surveillance. Knockdown of all members of the PAF1 family of proteins enhanced HIV-1 reverse transcription and integration of provirus. Over-expression of PAF1 in host cells renders them refractory to HIV-1. Simian Immunodeficiency Viruses and HIV-2 are also restricted in PAF1 expressing cells. PAF1 is expressed in primary monocytes, macrophages and T-lymphocytes and we demonstrate strong activity in MonoMac1, a monocyte cell line. Conclusions We propose that the PAF1c establishes an anti-viral state to prevent infection by incoming retroviruses. This previously unrecognised mechanism of restriction could have implications for invasion of cells by any pathogen.

  5. 以HIV-1Vif与人APOBEC3G为靶点的抗HIV-1药物的研究方法%Research methods of antiHIV-1 inhibitors targeting at Vif-APOBEC3G axis

    Institute of Scientific and Technical Information of China (English)

    乔新华; 张文俊; 李泽琳; 曾毅

    2011-01-01

    The mammalian APOBEC3G protein( apolipoprotein B mRNA-editing enzyme catalytic polypeptide 3 protein G,APOBEC3G) is an important component of the cellular innate immune response to retroviral infection. APOBEC3G can extinguish HIV-1 ( human immunodeficiency virus type 1 ) infectivity by its incorporation into virus particles and subsequent cytosine deaminase activity to block replication of HIV-1. HIV-1 Vif ( viral infectivity factor) suppresses various APOBEC3 proteins through a common mechanism which induces the degradation of target proteins. Therefore, the interrelation of Vif-APOBEC3G has been extensively studied, which represents attractive targets for the development of novel inhibitors. We summarize the papers in which the detection technique and methords have been developed to assay the anti-HIV activity and its mechanism, such as western-blotting, co-immunoprecipitation,pulse-chase experiments,bioluminescence resonance energy transfer, biomolecular interaction analysis. This review is towards developing therapeutics aimed at the Vif -APOBEC3G axis.%人载脂蛋白B mRNA编辑酶催化多肽样蛋白3G(apolipoprotein B mRNA-editing enzyme catalytic polypeptide 3 protein G,APOBEC3G)是宿主的抗HIV-1(human immunodeficiency virus type Ⅰ)因子,而HIV-1辅助蛋白--病毒感染因子Vif(viral infectivity factor)可通过介导蛋白酶体途径降解APOBEC3G,因此针对APOBEC3G及HIV-1Vif进行抑制剂设计已经成为抗HIV-1药物研究新的方向之一,相应用于研究Vif-APOBEC3G相互作用的方法也越来越多,如免疫印迹、免疫杂交、脉冲追踪试验、生物发光共振能量转移检测、BIAcore检测等.作者将目前用于以Vif-APOBEC3G为靶点的药物的筛选及作用机制的研究方法进行了综述,为基于此的研究提供了策略.

  6. Estimating the fraction of progeny virions that must incorporate APOBEC3G for suppression of productive HIV-1 infection

    Energy Technology Data Exchange (ETDEWEB)

    Thangavelu, Pulari U.; Gupta, Vipul; Dixit, Narendra M., E-mail: narendra@chemeng.iisc.ernet.in

    2014-01-20

    The contest between the host factor APOBEC3G (A3G) and the HIV-1 protein Vif presents an attractive target of intervention. The extent to which the A3G–Vif interaction must be suppressed to tilt the balance in favor of A3G remains unknown. We employed stochastic simulations and mathematical modeling of the within-host dynamics and evolution of HIV-1 to estimate the fraction of progeny virions that must incorporate A3G to render productive infection unsustainable. Using three different approaches, we found consistently that a transition from sustained infection to suppression of productive infection occurred when the latter fraction exceeded ∼0.8. The transition was triggered by A3G-induced hypermutations that led to premature stop codons compromising viral production and was consistent with driving the basic reproductive number, R{sub 0}, below unity. The fraction identified may serve as a quantitative guideline for strategies targeting the A3G–Vif axis. - Highlights: • We perform simulations and mathematical modeling of the role of APOBEC3G in suppressing HIV-1 infection. • In three distinct ways, we estimate that when over 80% of progeny virions carry APOBEC3G, productive HIV-1 infection would be suppressed. • Our estimate of this critical fraction presents quantitative guidelines for strategies targeting the APOBEC3G–Vif axis.

  7. Feline Immunodeficiency Virus Vif N-Terminal Residues Selectively Counteract Feline APOBEC3s.

    Science.gov (United States)

    Gu, Qinyong; Zhang, Zeli; Cano Ortiz, Lucía; Franco, Ana Cláudia; Häussinger, Dieter; Münk, Carsten

    2016-12-01

    Feline immunodeficiency virus (FIV) Vif protein counteracts feline APOBEC3s (FcaA3s) restriction factors by inducing their proteasomal degradation. The functional domains in FIV Vif for interaction with FcaA3s are poorly understood. Here, we have identified several motifs in FIV Vif that are important for selective degradation of different FcaA3s. Cats (Felis catus) express three types of A3s: single-domain A3Z2, single-domain A3Z3, and double-domain A3Z2Z3. We proposed that FIV Vif would selectively interact with the Z2 and the Z3 A3s. Indeed, we identified two N-terminal Vif motifs (12LF13 and 18GG19) that specifically interacted with the FcaA3Z2 protein but not with A3Z3. In contrast, the exclusive degradation of FcaA3Z3 was regulated by a region of three residues (M24, L25, and I27). Only a FIV Vif carrying a combination of mutations from both interaction sites lost the capacity to degrade and counteract FcaA3Z2Z3. However, alterations in the specific A3s interaction sites did not affect the cellular localization of the FIV Vif protein and binding to feline A3s. Pulldown experiments demonstrated that the A3 binding region localized to FIV Vif residues 50 to 80, outside the specific A3 interaction domain. Finally, we found that the Vif sites specific to individual A3s are conserved in several FIV lineages of domestic cat and nondomestic cats, while being absent in the FIV Vif of pumas. Our data support a complex model of multiple Vif-A3 interactions in which the specific region for selective A3 counteraction is discrete from a general A3 binding domain.

  8. ASK1 restores the antiviral activity of APOBEC3G by disrupting HIV-1 Vif-mediated counteraction.

    Science.gov (United States)

    Miyakawa, Kei; Matsunaga, Satoko; Kanou, Kazuhiko; Matsuzawa, Atsushi; Morishita, Ryo; Kudoh, Ayumi; Shindo, Keisuke; Yokoyama, Masaru; Sato, Hironori; Kimura, Hirokazu; Tamura, Tomohiko; Yamamoto, Naoki; Ichijo, Hidenori; Takaori-Kondo, Akifumi; Ryo, Akihide

    2015-04-22

    APOBEC3G (A3G) is an innate antiviral restriction factor that strongly inhibits the replication of human immunodeficiency virus type 1 (HIV-1). An HIV-1 accessory protein, Vif, hijacks the host ubiquitin-proteasome system to execute A3G degradation. Identification of the host pathways that obstruct the action of Vif could provide a new strategy for blocking viral replication. We demonstrate here that the host protein ASK1 (apoptosis signal-regulating kinase 1) interferes with the counteraction by Vif and revitalizes A3G-mediated viral restriction. ASK1 binds the BC-box of Vif, thereby disrupting the assembly of the Vif-ubiquitin ligase complex. Consequently, ASK1 stabilizes A3G and promotes its incorporation into viral particles, ultimately reducing viral infectivity. Furthermore, treatment with the antiretroviral drug AZT (zidovudine) induces ASK1 expression and restores the antiviral activity of A3G in HIV-1-infected cells. This study thus demonstrates a distinct function of ASK1 in restoring the host antiviral system that can be enhanced by AZT treatment.

  9. A computational analysis of the structural determinants of APOBEC3's catalytic activity and vulnerability to HIV-1 Vif.

    Science.gov (United States)

    Shandilya, Shivender M D; Bohn, Markus-Frederik; Schiffer, Celia A

    2014-12-01

    APOBEC3s (A3) are Zn(2+) dependent cytidine deaminases with diverse biological functions and implications for cancer and immunity. Four of the seven human A3s restrict HIV by 'hypermutating' the reverse-transcribed viral genomic DNA. HIV Virion Infectivity Factor (Vif) counters this restriction by targeting A3s to proteasomal degradation. However, there is no apparent correlation between catalytic activity, Vif binding, and sequence similarity between A3 domains. Our comparative structural analysis reveals features required for binding Vif and features influencing polynucleotide deaminase activity in A3 proteins. All Vif-binding A3s share a negatively charged surface region that includes residues previously implicated in binding the highly-positively charged Vif. Additionally, catalytically active A3s share a positively charged groove near the Zn(2+) coordinating active site, which may accommodate the negatively charged polynucleotide substrate. Our findings suggest surface electrostatics, as well as the spatial extent of substrate accommodating region, are critical determinants of substrate and Vif binding across A3 proteins with implications for anti-retroviral and anti-cancer therapeutic design.

  10. Target cell APOBEC3C can induce limited G-to-A mutation in HIV-1.

    Directory of Open Access Journals (Sweden)

    Khaoula Bourara

    2007-10-01

    Full Text Available The evolutionary success of primate lentiviruses reflects their high capacity to mutate and adapt to new host species, immune responses within individual hosts, and, in recent years, antiviral drugs. APOBEC3G (A3G and APOBEC3F (A3F are host cell DNA-editing enzymes that induce extensive HIV-1 mutation that severely attenuates viral replication. The HIV-1 virion infectivity factor (Vif, expressed in vivo, counteracts the antiviral activity of A3G and A3F by inducing their degradation. Other APOBECs may contribute more to viral diversity by inducing less extensive mutations allowing viral replication to persist. Here we show that in APOBEC3C (A3C-expressing cells infected with the patient-derived HIV-1 molecular clones 210WW, 210WM, 210MW, and 210MM, and the lab-adapted molecular clone LAI, viral G-to-A mutations were detected in the presence of Vif expression. Mutations occurred primarily in the GA context and were relatively infrequent, thereby allowing for spreading infection. The mutations were absent in cells lacking A3C but were induced after transient expression of A3C in the infected target cell. Inhibiting endogenous A3C by RNA interference in Magi cells prevented the viral mutations. Thus, A3C is necessary and sufficient for G-to-A mutations in some HIV-1 strains. A3C-induced mutations occur at levels that allow replication to persist and may therefore contribute to viral diversity. Developing drugs that inhibit A3C may be a novel strategy for delaying viral escape from immune or antiretroviral inhibition.

  11. Target Cell APOBEC3C Can Induce Limited G-to-A Mutation in HIV-1

    Science.gov (United States)

    Bourara, Khaoula; Liegler, Teri J; Grant, Robert M

    2007-01-01

    The evolutionary success of primate lentiviruses reflects their high capacity to mutate and adapt to new host species, immune responses within individual hosts, and, in recent years, antiviral drugs. APOBEC3G (A3G) and APOBEC3F (A3F) are host cell DNA-editing enzymes that induce extensive HIV-1 mutation that severely attenuates viral replication. The HIV-1 virion infectivity factor (Vif), expressed in vivo, counteracts the antiviral activity of A3G and A3F by inducing their degradation. Other APOBECs may contribute more to viral diversity by inducing less extensive mutations allowing viral replication to persist. Here we show that in APOBEC3C (A3C)-expressing cells infected with the patient-derived HIV-1 molecular clones 210WW, 210WM, 210MW, and 210MM, and the lab-adapted molecular clone LAI, viral G-to-A mutations were detected in the presence of Vif expression. Mutations occurred primarily in the GA context and were relatively infrequent, thereby allowing for spreading infection. The mutations were absent in cells lacking A3C but were induced after transient expression of A3C in the infected target cell. Inhibiting endogenous A3C by RNA interference in Magi cells prevented the viral mutations. Thus, A3C is necessary and sufficient for G-to-A mutations in some HIV-1 strains. A3C-induced mutations occur at levels that allow replication to persist and may therefore contribute to viral diversity. Developing drugs that inhibit A3C may be a novel strategy for delaying viral escape from immune or antiretroviral inhibition. PMID:17967058

  12. Intracellular interactions between APOBEC3G, RNA, and HIV-1 Gag: APOBEC3G multimerization is dependent on its association with RNA

    Directory of Open Access Journals (Sweden)

    Friew Yeshitila N

    2009-06-01

    Full Text Available Abstract Background Host restriction factor APOBEC3G (A3G blocks human immunodeficiency virus type 1 (HIV-1 replication by G-to-A hypermutation, and by inhibiting DNA synthesis and provirus formation. Previous reports have suggested that A3G is a dimer and its virion incorporation is mediated through interactions with viral or nonviral RNAs and/or HIV-1 Gag. We have now employed a bimolecular fluorescence complementation assay (BiFC to analyze the intracellular A3G-A3G, A3G-RNA, and A3G-Gag interactions in living cells by reconstitution of yellow fluorescent protein (YFP from its N- or C-terminal fragments. Results The results obtained with catalytic domain 1 and 2 (CD1 and CD2 mutants indicate that A3G-A3G and A3G-Gag multimerization is dependent on an intact CD1 domain, which is required for RNA binding. A mutant HIV-1 Gag that exhibits reduced RNA binding also failed to reconstitute BiFC with wild-type A3G, indicating a requirement for both HIV-1 Gag and A3G to bind to RNA for their multimerization. Addition of a non-specific RNA binding peptide (P22 to the N-terminus of a CD1 mutant of A3G restored BiFC and virion incorporation, but failed to inhibit viral replication, indicating that the mutations in CD1 resulted in additional defects that interfere with A3G's antiviral activity. Conclusion These studies establish a robust BiFC assay for analysis of intracellular interactions of A3G with other macromolecules. The results indicate that in vivo A3G is a monomer that forms multimers upon binding to RNA. In addition, we observed weak interactions between wild-type A3G molecules and RNA binding-defective mutants of A3G, which could explain previously described protein-protein interactions between purified A3G molecules.

  13. CBFβ stabilizes HIV Vif to counteract APOBEC3 at the expense of RUNX1 target gene expression.

    Science.gov (United States)

    Kim, Dong Young; Kwon, Eunju; Hartley, Paul D; Crosby, David C; Mann, Sumanjit; Krogan, Nevan J; Gross, John D

    2013-02-21

    The HIV-1 accessory protein Vif hijacks a cellular Cullin-RING ubiquitin ligase, CRL5, to promote degradation of the APOBEC3 (A3) family of restriction factors. Recently, the cellular transcription cofactor CBFβ was shown to form a complex with CRL5-Vif and to be essential for A3 degradation and viral infectivity. We now demonstrate that CBFβ is required for assembling a well-ordered CRL5-Vif complex by inhibiting Vif oligomerization and by activating CRL5-Vif via direct interaction. The CRL5-Vif-CBFβ holoenzyme forms a well-defined heterohexamer, indicating that Vif simultaneously hijacks CRL5 and CBFβ. Heterodimers of CBFβ and RUNX transcription factors contribute toward the regulation of genes, including those with immune system functions. We show that binding of Vif to CBFβ is mutually exclusive with RUNX heterodimerization and impacts the expression of genes whose regulatory domains are associated with RUNX1. Our results provide a mechanism by which a pathogen with limited coding capacity uses one factor to hijack multiple host pathways.

  14. Pokeweed antiviral protein restores levels of cellular APOBEC3G during HIV-1 infection by depurinating Vif mRNA.

    Science.gov (United States)

    Krivdova, Gabriela; Hudak, Katalin A

    2015-10-01

    Pokeweed antiviral protein (PAP) is an RNA glycosidase that inhibits production of human immunodeficiency virus type 1 (HIV-1) when expressed in human culture cells. Previously, we showed that the expression of PAP reduced the levels of several viral proteins, including virion infectivity factor (Vif). However, the mechanism causing Vif reduction and the consequences of the inhibition were not determined. Here we show that the Vif mRNA is directly depurinated by PAP. Because of depurination at two specific sites within the Vif ORF, Vif levels decrease during infections and the progeny viruses that are generated are ∼ 10-fold less infectious and compromised for proviral integration. These results are consistent with PAP activity inhibiting translation of Vif, which in turn reduces the effect of Vif to inactivate the host restriction factor APOBEC3G (apolipoprotein B mRNA-editing enzyme, catalytic polypeptide-like editing complex 3G). Our findings identify Vif mRNA as a new substrate for PAP and demonstrate that derepression of innate immunity against HIV-1 contributes to its antiviral activity.

  15. Crystal structure of the DNA cytosine deaminase APOBEC3F: the catalytically active and HIV-1 Vif-binding domain.

    Science.gov (United States)

    Bohn, Markus-Frederik; Shandilya, Shivender M D; Albin, John S; Kouno, Takahide; Anderson, Brett D; McDougle, Rebecca M; Carpenter, Michael A; Rathore, Anurag; Evans, Leah; Davis, Ahkillah N; Zhang, Jingying; Lu, Yongjian; Somasundaran, Mohan; Matsuo, Hiroshi; Harris, Reuben S; Schiffer, Celia A

    2013-06-04

    Human APOBEC3F is an antiretroviral single-strand DNA cytosine deaminase, susceptible to degradation by the HIV-1 protein Vif. In this study the crystal structure of the HIV Vif binding, catalytically active, C-terminal domain of APOBEC3F (A3F-CTD) was determined. The A3F-CTD shares structural motifs with portions of APOBEC3G-CTD, APOBEC3C, and APOBEC2. Residues identified to be critical for Vif-dependent degradation of APOBEC3F all fit within a predominantly negatively charged contiguous region on the surface of A3F-CTD. Specific sequence motifs, previously shown to play a role in Vif susceptibility and virion encapsidation, are conserved across APOBEC3s and between APOBEC3s and HIV-1 Vif. In this structure these motifs pack against each other at intermolecular interfaces, providing potential insights both into APOBEC3 oligomerization and Vif interactions.

  16. Multi-scale modeling of HIV infection in vitro and APOBEC3G-based anti-retroviral therapy.

    Directory of Open Access Journals (Sweden)

    Iraj Hosseini

    2012-02-01

    Full Text Available The human APOBEC3G is an innate restriction factor that, in the absence of Vif, restricts HIV-1 replication by inducing excessive deamination of cytidine residues in nascent reverse transcripts and inhibiting reverse transcription and integration. To shed light on impact of A3G-Vif interactions on HIV replication, we developed a multi-scale computational system consisting of intracellular (single-cell, cellular and extracellular (multicellular events by using ordinary differential equations. The single-cell model describes molecular-level events within individual cells (such as production and degradation of host and viral proteins, and assembly and release of new virions, whereas the multicellular model describes the viral dynamics and multiple cycles of infection within a population of cells. We estimated the model parameters either directly from previously published experimental data or by running simulations to find the optimum values. We validated our integrated model by reproducing the results of in vitro T cell culture experiments. Crucially, both downstream effects of A3G (hypermutation and reduction of viral burst size were necessary to replicate the experimental results in silico. We also used the model to study anti-HIV capability of several possible therapeutic strategies including: an antibody to Vif; upregulation of A3G; and mutated forms of A3G. According to our simulations, A3G with a mutated Vif binding site is predicted to be significantly more effective than other molecules at the same dose. Ultimately, we performed sensitivity analysis to identify important model parameters. The results showed that the timing of particle formation and virus release had the highest impacts on HIV replication. The model also predicted that the degradation of A3G by Vif is not a crucial step in HIV pathogenesis.

  17. Increased expression and dysregulated association of restriction factors and type I interferon in HIV, HCV mono- and co-infected patients.

    Science.gov (United States)

    Zhu, Jia-Wu; Liu, Feng-Liang; Mu, Dan; Deng, De-Yao; Zheng, Yong-Tang

    2016-06-01

    Host restriction factors and type I interferon are important in limiting HIV and HCV infections, yet the role of HIV, HCV mono- and co-infection in regulating these antiviral genes expression is not clear. In this study, we measured the levels of TRIM5α, TRIM22, APOBEC3G, and IFN-α, -β mRNA expression in peripheral blood mononuclear cells of 43 HIV mono-infected, 70 HCV mono-infected and 64 HIV/HCV co-infected patients along with 98 healthy controls. We also quantified HIV and HCV viral loads in mono- and co-infected patients. The results showed that HCV, HIV mono- and co-infection differentially increased TRIM22, APOBEC3G, and IFN-α, -β mRNA expression while the mRNA expression of TRIMα was upregulated only by HCV-mono infection. HIV/HCV co-infection was associated with higher viral load, compared to either HIV or HCV mono-infection. Additionally, we showed TRIMα and TRIM22 positively correlated with IFN-α, -β, which could be dysregulated by HIV, HCV mono- and co-infection. Furthermore, we found TRIM22 negatively correlated with HCV viral load in mono-infected patients and APOBEC3G positively correlated with HCV viral load in co-infected patients. Collectively, our findings suggest the potential role of restriction factors in restricting HIV, HCV mono- and co-infection in vivo, which appears to be a therapeutic target for potential drug discovery.

  18. Elevated APOBEC3B correlates with poor outcomes for estrogen-receptor-positive breast cancers.

    Science.gov (United States)

    Sieuwerts, Anieta M; Willis, Scooter; Burns, Michael B; Look, Maxime P; Meijer-Van Gelder, Marion E; Schlicker, Andreas; Heideman, Marinus R; Jacobs, Heinz; Wessels, Lodewyk; Leyland-Jones, Brian; Gray, Kathryn P; Foekens, John A; Harris, Reuben S; Martens, John W M

    2014-12-01

    Recent observations connected DNA cytosine deaminase APOBEC3B to the genetic evolution of breast cancer. We addressed whether APOBEC3B is associated with breast cancer clinical outcomes. APOBEC3B messenger RNA (mRNA) levels were related in 1,491 primary breast cancers to disease-free (DFS), metastasis-free (MFS), and overall survival (OS). For independent validation, APOBEC3B mRNA expression was associated with patient outcome data in five additional cohorts (over 3,500 breast cancer cases). In univariate Cox regression analysis, increasing APOBEC3B expression as a continuous variable was associated with worse DFS, MFS, and OS (hazard ratio [HR] = 1.20, 1.21, and 1.24, respectively; all P DFS (continuous variable: HR = 1.29, P = .001; dichotomized at the median level, HR = 1.66, P = .0002). This implies that APOBEC3B is a marker of pure prognosis in ER + disease. These findings were confirmed in the analyses of five independent patient sets. In these analyses, APOBEC3B expression dichotomized at the median level was associated with adverse outcomes (METABRIC discovery and validation, 788 and 706 ER + cases, disease-specific survival (DSS), HR = 1.77 and HR = 1.77, respectively, both P DFS, HR = 1.57, P = 2.46E-04; NKI295, 181 ER + cases, DFS, HR = 1.72, P = .054; and BIG 1-98, 1,219 ER + cases, breast-cancer-free interval (BCFI), HR = 1.42, P = 0.0079). APOBEC3B is a marker of pure prognosis and poor outcomes for ER + breast cancer, which strongly suggests that genetic aberrations induced by APOBEC3B contribute to breast cancer progression.

  19. Human APOBEC3 induced mutation of human immunodeficiency virus type-1 contributes to adaptation and evolution in natural infection.

    Directory of Open Access Journals (Sweden)

    Eun-Young Kim

    2014-07-01

    Full Text Available Human APOBEC3 proteins are cytidine deaminases that contribute broadly to innate immunity through the control of exogenous retrovirus replication and endogenous retroelement retrotransposition. As an intrinsic antiretroviral defense mechanism, APOBEC3 proteins induce extensive guanosine-to-adenosine (G-to-A mutagenesis and inhibit synthesis of nascent human immunodeficiency virus-type 1 (HIV-1 cDNA. Human APOBEC3 proteins have additionally been proposed to induce infrequent, potentially non-lethal G-to-A mutations that make subtle contributions to sequence diversification of the viral genome and adaptation though acquisition of beneficial mutations. Using single-cycle HIV-1 infections in culture and highly parallel DNA sequencing, we defined trinucleotide contexts of the edited sites for APOBEC3D, APOBEC3F, APOBEC3G, and APOBEC3H. We then compared these APOBEC3 editing contexts with the patterns of G-to-A mutations in HIV-1 DNA in cells obtained sequentially from ten patients with primary HIV-1 infection. Viral substitutions were highest in the preferred trinucleotide contexts of the edited sites for the APOBEC3 deaminases. Consistent with the effects of immune selection, amino acid changes accumulated at the APOBEC3 editing contexts located within human leukocyte antigen (HLA-appropriate epitopes that are known or predicted to enable peptide binding. Thus, APOBEC3 activity may induce mutations that influence the genetic diversity and adaptation of the HIV-1 population in natural infection.

  20. Endogenous origins of HIV-1 G-to-A hypermutation and restriction in the nonpermissive T cell line CEM2n.

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    Eric W Refsland

    Full Text Available The DNA deaminase APOBEC3G converts cytosines to uracils in retroviral cDNA, which are immortalized as genomic strand G-to-A hypermutations by reverse transcription. A single round of APOBEC3G-dependent mutagenesis can be catastrophic, but evidence suggests that sublethal levels contribute to viral genetic diversity and the associated problems of drug resistance and immune escape. APOBEC3G exhibits an intrinsic preference for the second cytosine in a 5'CC dinucleotide motif leading to 5'GG-to-AG mutations. However, an additional hypermutation signature is commonly observed in proviral sequences from HIV-1 infected patients, 5'GA-to-AA, and it has been attributed controversially to one or more of the six other APOBEC3 deaminases. An unambiguous resolution of this problem has been difficult to achieve, in part due to dominant effects of protein over-expression. Here, we employ gene targeting to dissect the endogenous APOBEC3 contribution to Vif-deficient HIV-1 restriction and hypermutation in a nonpermissive T cell line CEM2n. We report that APOBEC3G-null cells, as predicted from previous studies, lose the capacity to inflict 5'GG-to-AG mutations. In contrast, APOBEC3F-null cells produced viruses with near-normal mutational patterns. Systematic knockdown of other APOBEC3 genes in an APOBEC3F-null background revealed a significant contribution from APOBEC3D in promoting 5'GA-to-AA hypermutations. Furthermore, Vif-deficient HIV-1 restriction was strong in parental CEM2n and APOBEC3D-knockdown cells, partially alleviated in APOBEC3G- or APOBEC3F-null cells, further alleviated in APOBEC3F-null/APOBEC3D-knockdown cells, and alleviated to the greatest extent in APOBEC3F-null/APOBEC3G-knockdown cells revealing clear redundancy in the HIV-1 restriction mechanism. We conclude that endogenous levels of APOBEC3D, APOBEC3F, and APOBEC3G combine to restrict Vif-deficient HIV-1 and cause the hallmark dinucleotide hypermutation patterns in CEM2n. Primary T

  1. APOBEC3G-depleted resting CD4+ T cells remain refractory to HIV1 infection.

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    Francesca R Santoni de Sio

    Full Text Available BACKGROUND: CD4+ T lymphocytes are the primary targets of HIV1 but cannot be infected when fully quiescent, due to a post-entry block preventing the completion of reverse transcription. Chiu et al. recently proposed that this restriction reflects the action of APOBEC3G (A3G. They further suggested that T cell activation abrogates the A3G-mediated block by directing this protein to a high molecular mass complex. METHODOLOGY/PRINCIPAL FINDINGS: In the present work, we sought to explore further this model. However, we found that effective suppression of A3G by combined RNA interference and expression of HIV1 Vif does not relieve the restrictive phenotype of post-activation resting T cells. We also failed to find a correlation between HIV resistance and the presence of A3G in a low molecular complex in primary T cells. CONCLUSIONS/SIGNIFICANCE: We conclude that A3G is unlikely to play a role in the HIV restrictive phenotype of quiescent T lymphocytes.

  2. Expression of murine APOBEC3 alleles in different mouse strains and their effect on mouse mammary tumor virus infection.

    Science.gov (United States)

    Okeoma, Chioma M; Petersen, Josiah; Ross, Susan R

    2009-04-01

    Recent work has shown that mouse APOBEC3 restricts infection by mouse mammary tumor virus (MMTV) and murine leukemia virus (MLV) and that there are polymorphic APOBEC3 alleles found in different inbred mouse strains. For example, C57BL/6 mice, which are resistant to Friend MLV (F-MLV), encode a APOBEC3 gene different from that encoded by F-MLV-susceptible BALB/c mice; the predominant RNA produced in C57BL/6 mice lacks exon 5 (mA3(-5)) and encodes a protein with 15 polymorphic amino acids. It has also been reported that BALB/c mice produce only a variant RNA that lacks exon 2 (mA3(-2)). In this study, we examined the effect of these polymorphic APOBEC3 proteins on MMTV infection. We found that the major RNA made in C57BL/6 and B10.BR mice lacks exon 5 but that BALB/c and C3H/HeN mice predominantly express an RNA that contains all nine exons. In addition to producing the splice variant, C57BL/6 and B10.BR cells and tissues had levels of mA3 RNA fivefold higher than those from BALB/c and C3H/HeN mice. A cloned C57BL/6-derived mA3 protein lacking exon 5 inhibited MMTV infection better than a cloned full-length protein derived from 129/Ola RNA when packaged into MMTV virions. We also tested dendritic cells derived from different inbred mouse strains for their abilities to be infected by MMTV and showed that susceptibility to infection correlated with the presence of the exon 5-encoding allele. In vivo susceptibility to infection cosegregated with the inherited mA3 allele in a C57BL/6 x BALB/c backcross analysis. Moreover, virus produced in vivo in the mammary tissue of mA3 knockout and BALB/c mice was more infectious than that produced in the tissue of C57BL/6 mice. These data indicate that mA3 plays a role in the genetics of susceptibility and resistance to MMTV infection.

  3. Inhibition of LINE-1 and Alu retrotransposition by exosomes encapsidating APOBEC3G and APOBEC3F.

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    Khatua, Atanu K; Taylor, Harry E; Hildreth, James E K; Popik, Waldemar

    2010-04-25

    Human cytidine deaminases, including APOBEC3G (A3G) and A3F, are part of a cellular defense system against retroviruses and retroelements including non-LTR retrotransposons LINE-1 (L1) and Alu. Expression of cellular A3 proteins is sufficient for inhibition of L1 and Alu retrotransposition, but the effect of A3 proteins transferred in exosomes on retroelement mobilization is unknown. Here, we demonstrate for the first time that exosomes secreted by CD4(+)H9 T cells and mature monocyte-derived dendritic cells encapsidate A3G and A3F and inhibit L1 and Alu retrotransposition. A3G is the major contributor to the inhibitory activity of exosomes, however, the contribution of A3F in H9 exosomes cannot be excluded. Additionally, we show that exosomes encapsidate mRNAs coding for A3 proteins. A3G mRNA, and less so A3F, was enriched in exosomes secreted by H9 cells. Exosomal A3G mRNA was functional in vitro. Whether exosomes inhibit retrotransposons in vivo requires further investigation.

  4. Convergence and divergence in the evolution of the APOBEC3G-Vif interaction reveal ancient origins of simian immunodeficiency viruses.

    Science.gov (United States)

    Compton, Alex A; Emerman, Michael

    2013-01-01

    Naturally circulating lentiviruses are abundant in African primate species today, yet their origins and history of transmitting between hosts remain obscure. As a means to better understand the age of primate lentiviruses, we analyzed primate genomes for signatures of lentivirus-driven evolution. Specifically, we studied the adaptive evolution of host restriction factor APOBEC3G (A3G) in Old World Monkey (OWM) species. We find recurrent mutation of A3G in multiple primate lineages at sites that determine susceptibility to antagonism by the lentiviral accessory protein Vif. Using a broad panel of SIV Vif isolates, we demonstrate that natural variation in OWM A3G confers resistance to Vif-mediated degradation, suggesting that adaptive variants of the host factor were selected upon exposure to pathogenic lentiviruses at least 5-6 million years ago (MYA). Furthermore, in members of the divergent Colobinae subfamily of OWM, a multi-residue insertion event in A3G that arose at least 12 MYA blocks the activity of Vif, suggesting an even more ancient origin of SIV. Moreover, analysis of the lentiviruses associated with Colobinae monkeys reveal that the interface of the A3G-Vif interaction has shifted and given rise to a second genetic conflict. Our analysis of virus-driven evolution describes an ancient yet ongoing genetic conflict between simian primates and lentiviruses on a million-year time scale.

  5. Structural features of antiviral APOBEC3 proteins are linked to their functional activities

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    Shingo eKitamura

    2011-12-01

    Full Text Available APOBEC3 (A3 proteins are cellular cytidine deaminases that potently restrict the replication of retroviruses by hypermutating viral cDNA and/or inhibiting reverse transcription. There are seven members of this family including A3A, B, C, DE, F, G, and H, all encoded in a tandem array on human chromosome 22. A3F and A3G are the most potent inhibitors of HIV-1, but only in the absence of the virus-encoded protein, Vif. HIV-1 utilizes Vif to abrogate A3 functions in the producer cells. More specifically, Vif, serving as a substrate receptor, facilitates ubiquitination of A3 proteins by forming a Cullin5 (Cul5-based E3 ubiquitin ligase complex, which targets A3 proteins for rapid proteasomal degradation. The specificity of A3 degradation is determined by the ability of Vif to bind to the target. Several lines of evidence have suggested that three distinct regions of A3 proteins are involved in the interaction with Vif. Here, we review the biological functions of A3 family members with special focus on A3G and base our analysis on the available structural information.

  6. Identification of the HIV-1 Vif and Human APOBEC3G Protein Interface.

    Science.gov (United States)

    Letko, Michael; Booiman, Thijs; Kootstra, Neeltje; Simon, Viviana; Ooms, Marcel

    2015-12-01

    Human cells express natural antiviral proteins, such as APOBEC3G (A3G), that potently restrict HIV replication. As a counter-defense, HIV encodes the accessory protein Vif, which binds A3G and mediates its proteasomal degradation. Our structural knowledge on how Vif and A3G interact is limited, because a co-structure is not available. We identified specific points of contact between Vif and A3G by using functional assays with full-length A3G, patient-derived Vif variants, and HIV forced evolution. These anchor points were used to model and validate the Vif-A3G interface. The resultant co-structure model shows that the negatively charged β4-α4 A3G loop, which contains primate-specific variation, is the core Vif binding site and forms extensive interactions with a positively charged pocket in HIV Vif. Our data present a functional map of this viral-host interface and open avenues for targeted approaches to block HIV replication by obstructing the Vif-A3G interaction.

  7. The DNA cytosine deaminase APOBEC3B promotes tamoxifen resistance in ER-positive breast cancer

    Science.gov (United States)

    Law, Emily K.; Sieuwerts, Anieta M.; LaPara, Kelly; Leonard, Brandon; Starrett, Gabriel J.; Molan, Amy M.; Temiz, Nuri A.; Vogel, Rachel Isaksson; Meijer-van Gelder, Marion E.; Sweep, Fred C. G. J.; Span, Paul N.; Foekens, John A.; Martens, John W. M.; Yee, Douglas; Harris, Reuben S.

    2016-01-01

    Breast tumors often display extreme genetic heterogeneity characterized by hundreds of gross chromosomal aberrations and tens of thousands of somatic mutations. Tumor evolution is thought to be ongoing and driven by multiple mutagenic processes. A major outstanding question is whether primary tumors have preexisting mutations for therapy resistance or whether additional DNA damage and mutagenesis are necessary. Drug resistance is a key measure of tumor evolvability. If a resistance mutation preexists at the time of primary tumor presentation, then the intended therapy is likely to fail. However, if resistance does not preexist, then ongoing mutational processes still have the potential to undermine therapeutic efficacy. The antiviral enzyme APOBEC3B (apolipoprotein B mRNA-editing enzyme, catalytic polypeptide-like 3B) preferentially deaminates DNA C-to-U, which results in signature C-to-T and C-to-G mutations commonly observed in breast tumors. We use clinical data and xenograft experiments to ask whether APOBEC3B contributes to ongoing breast tumor evolution and resistance to the selective estrogen receptor modulator, tamoxifen. First, APOBEC3B levels in primary estrogen receptor–positive (ER+) breast tumors inversely correlate with the clinical benefit of tamoxifen in the treatment of metastatic ER+ disease. Second, APOBEC3B depletion in an ER+ breast cancer cell line results in prolonged tamoxifen responses in murine xenograft experiments. Third, APOBEC3B overexpression accelerates the development of tamoxifen resistance in murine xenograft experiments by a mechanism that requires the enzyme’s catalytic activity. These studies combine to indicate that APOBEC3B promotes drug resistance in breast cancer and that inhibiting APOBEC3B-dependent tumor evolvability may be an effective strategy to improve efficacies of targeted cancer therapies. PMID:27730215

  8. 固有免疫的新成员——APOBEC3G

    Institute of Scientific and Technical Information of China (English)

    吴小霞; 马义才

    2005-01-01

    最近,对Vif的研究揭示了固有免疫的新成员——APOBEC3G,它是胞苷脱氨酶,致死性突变反转录病毒和反转录元件。APOBEC3G属于APOBEC家族,以DNA编辑的方式抑制反转录病毒复制,如HIV-1。APOBEC3G是广谱的抗病毒蛋白,对HBV也有强烈的抑制作用,但是作用机制有所不同。

  9. APOBEC3G抗HIV-1作用机制研究进展

    Institute of Scientific and Technical Information of China (English)

    饶贤高; 况轶群; 郑永唐

    2008-01-01

    APOBEC3G是细胞内新的广谱抗病毒蛋白.它具有胞苷脱氨酶活性,能使病毒负链DNA产生dC→dU高发突变,造成正链DNA G→A突变,使得病毒DNA变成无功能或降解.APO-BEC3G具有广泛的生物学功能,可以限制HIV-1等病毒复制,但HIV-1病毒感染因子Vif能拮抗APOBEC3G抑制病毒活性作用.本文简要综述了APOBEC3G抑制病毒HIV-1作用机制的最新进展.

  10. Lineage-Specific Viral Hijacking of Non-canonical E3 Ubiquitin Ligase Cofactors in the Evolution of Vif Anti-APOBEC3 Activity.

    Science.gov (United States)

    Kane, Joshua R; Stanley, David J; Hultquist, Judd F; Johnson, Jeffrey R; Mietrach, Nicole; Binning, Jennifer M; Jónsson, Stefán R; Barelier, Sarah; Newton, Billy W; Johnson, Tasha L; Franks-Skiba, Kathleen E; Li, Ming; Brown, William L; Gunnarsson, Hörður I; Adalbjornsdóttir, Adalbjorg; Fraser, James S; Harris, Reuben S; Andrésdóttir, Valgerður; Gross, John D; Krogan, Nevan J

    2015-05-26

    HIV-1 encodes the accessory protein Vif, which hijacks a host Cullin-RING ubiquitin ligase (CRL) complex as well as the non-canonical cofactor CBFβ, to antagonize APOBEC3 antiviral proteins. Non-canonical cofactor recruitment to CRL complexes by viral factors, to date, has only been attributed to HIV-1 Vif. To further study this phenomenon, we employed a comparative approach combining proteomic, biochemical, structural, and virological techniques to investigate Vif complexes across the lentivirus genus, including primate (HIV-1 and simian immunodeficiency virus macaque [SIVmac]) and non-primate (FIV, BIV, and MVV) viruses. We find that CBFβ is completely dispensable for the activity of non-primate lentiviral Vif proteins. Furthermore, we find that BIV Vif requires no cofactor and that MVV Vif requires a novel cofactor, cyclophilin A (CYPA), for stable CRL complex formation and anti-APOBEC3 activity. We propose modular conservation of Vif complexes allows for potential exaptation of functions through the acquisition of non-CRL-associated host cofactors while preserving anti-APOBEC3 activity.

  11. Lineage-Specific Viral Hijacking of Non-canonical E3 Ubiquitin Ligase Cofactors in the Evolution of Vif Anti-APOBEC3 Activity

    Directory of Open Access Journals (Sweden)

    Joshua R. Kane

    2015-05-01

    Full Text Available HIV-1 encodes the accessory protein Vif, which hijacks a host Cullin-RING ubiquitin ligase (CRL complex as well as the non-canonical cofactor CBFβ, to antagonize APOBEC3 antiviral proteins. Non-canonical cofactor recruitment to CRL complexes by viral factors, to date, has only been attributed to HIV-1 Vif. To further study this phenomenon, we employed a comparative approach combining proteomic, biochemical, structural, and virological techniques to investigate Vif complexes across the lentivirus genus, including primate (HIV-1 and simian immunodeficiency virus macaque [SIVmac] and non-primate (FIV, BIV, and MVV viruses. We find that CBFβ is completely dispensable for the activity of non-primate lentiviral Vif proteins. Furthermore, we find that BIV Vif requires no cofactor and that MVV Vif requires a novel cofactor, cyclophilin A (CYPA, for stable CRL complex formation and anti-APOBEC3 activity. We propose modular conservation of Vif complexes allows for potential exaptation of functions through the acquisition of non-CRL-associated host cofactors while preserving anti-APOBEC3 activity.

  12. Inhibition of hepatitis B virus replication by APOBEC3G in vitro and in vivo

    Institute of Scientific and Technical Information of China (English)

    Yan-Chang Lei; Dong-Liang Yang; You-Hua Hao; Zheng-Mao Zhang; Yong-Jun Tian; Bao-Ju Wang; Yan Yang; Xi-Ping Zhao; Meng-Ji Lu; Fei-Li Gong

    2006-01-01

    AIM: To investigate the effect of APOBEC3G mediated antiviral activity against hepatitis B virus (HBV) in cell cultures and replication competent HBV vector-based mouse model.METHODS: The mammalian hepatoma cells Huh7 and HepG2 were cotransfected with various amounts of CMV-driven expression vector encoding APOBEC3G and replication competent 1.3 fold over-length HBV. Levels of HBsAg and HBeAg in the media of the transfected cells were determined by ELISA. The expression of HBcAg in transfected cells was detected by western blot. HBV DNA and RNA from intracellular core particles were examined by Northern and Southern blot analyses. To assess activity of the APOBEC3G in vivo, an HBV vector-based model was used in which APOBEC3G and the HBV vector were co-delivered via high-volume tail vein injection.Levels of HBsAg and HBV DNA in the sera of mice as well as HBV core-associated RNA in the liver of mice were determined by ELISA and quantitative PCR analysis respectively.RESULTS: There was a dose dependent decrease in the levels of intracellular core-associated HBV DNA and extracellular production of HBsAg and HBeAg. The levels of intracellular core-associated viral RNA also decreased,but the expression of HBcAg in transfected cells showed almost no change. Consistent with in vitro results,levels of HBsAg in the sera of mice were dramatically decreased. More than 1.5 log10 decrease in levels of serum HBV DNA and liver HBV RNA were observed in the APOBEC3G-treated groups compared with the control groups.CONCLUSION: These findings indicate that APOBEC3G could suppress HBV replication and antigen expression both in vivo and in vitro, promising an advance in treatment of HBV infection.

  13. Retroelements versus APOBEC3 family members: No great escape from the magnificent seven

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    Juan F Arias

    2012-08-01

    Full Text Available Retroelements comprise a large and successful family of transposable genetic elements that, through intensive infiltration, have shaped the genomes of humans and other mammals over millions of years. In fact, retrotransposons now account for approximately 45% of the human genome. Based on their genomic mobility, some retroelements are known to be the cause of genetic diseases, not only in germ and embryonic stem cells but also in somatic cells, posing a threat to genomic stability throughout all cellular populations. In response, mammals have developed intrinsic immunity mechanisms that provide resistance against the threat of the deleterious effects of retrotransposition. Among these, seven members of the APOBEC3 (A3 family of cytidine deaminases serve as highly active, intrinsic, antiretroviral host factors. Certain A3 proteins effectively counteract infections of retroviruses such as HIV-1, as well as those of other virus families, while also blocking the transposition of retroelements. Based on their preferential expression in the germ cells, in which retrotransposons may be active, it is likely that A3 proteins were acquired through mammalian evolution primarily to inhibit retrotransposition and thereby maintain genomic stability in these cells. This review summarizes the recent advances in our understanding of the interplay between the retroelements currently active in the human genome and the anti-retroelement A3 proteins.

  14. First-In-Class Small Molecule Inhibitors of the Single-Strand DNA Cytosine Deaminase APOBEC3G

    Energy Technology Data Exchange (ETDEWEB)

    Li, Ming; Shandilya, Shivender M.D.; Carpenter, Michael A.; Rathore, Anurag; Brown, William L.; Perkins, Angela L.; Harki, Daniel A.; Solberg, Jonathan; Hook, Derek J.; Pandey, Krishan K.; Parniak, Michael A.; Johnson, Jeffrey R.; Krogan, Nevan J.; Somasundaran, Mohan; Ali, Akbar; Schiffer, Celia A.; Harris, Reuben S. (Pitt); (UMASS, MED); (SLUHSC); (UCSF); (UMM)

    2012-04-04

    APOBEC3G is a single-stranded DNA cytosine deaminase that comprises part of the innate immune response to viruses and transposons. Although APOBEC3G is the prototype for understanding the larger mammalian polynucleotide deaminase family, no specific chemical inhibitors exist to modulate its activity. High-throughput screening identified 34 compounds that inhibit APOBEC3G catalytic activity. Twenty of 34 small molecules contained catechol moieties, which are known to be sulfhydryl reactive following oxidation to the orthoquinone. Located proximal to the active site, C321 was identified as the binding site for the inhibitors by a combination of mutational screening, structural analysis, and mass spectrometry. Bulkier substitutions C321-to-L, F, Y, or W mimicked chemical inhibition. A strong specificity for APOBEC3G was evident, as most compounds failed to inhibit the related APOBEC3A enzyme or the unrelated enzymes E. coli uracil DNA glycosylase, HIV-1 RNase H, or HIV-1 integrase. Partial, but not complete, sensitivity could be conferred to APOBEC3A by introducing the entire C321 loop from APOBEC3G. Thus, a structural model is presented in which the mechanism of inhibition is both specific and competitive, by binding a pocket adjacent to the APOBEC3G active site, reacting with C321, and blocking access to substrate DNA cytosines.

  15. Likely role of APOBEC3G-mediated G-to-A mutations in HIV-1 evolution and drug resistance.

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    Patric Jern

    2009-04-01

    Full Text Available The role of APOBEC3 (A3 protein family members in inhibiting retrovirus infection and mobile element retrotransposition is well established. However, the evolutionary effects these restriction factors may have had on active retroviruses such as HIV-1 are less well understood. An HIV-1 variant that has been highly G-to-A mutated is unlikely to be transmitted due to accumulation of deleterious mutations. However, G-to-A mutated hA3G target sequences within which the mutations are the least deleterious are more likely to survive selection pressure. Thus, among hA3G targets in HIV-1, the ratio of nonsynonymous to synonymous changes will increase with virus generations, leaving a footprint of past activity. To study such footprints in HIV-1 evolution, we developed an in silico model based on calculated hA3G target probabilities derived from G-to-A mutation sequence contexts in the literature. We simulated G-to-A changes iteratively in independent sequential HIV-1 infections until a stop codon was introduced into any gene. In addition to our simulation results, we observed higher ratios of nonsynonymous to synonymous mutation at hA3G targets in extant HIV-1 genomes than in their putative ancestral genomes, compared to random controls, implying that moderate levels of A3G-mediated G-to-A mutation have been a factor in HIV-1 evolution. Results from in vitro passaging experiments of HIV-1 modified to be highly susceptible to hA3G mutagenesis verified our simulation accuracy. We also used our simulation to examine the possible role of A3G-induced mutations in the origin of drug resistance. We found that hA3G activity could have been responsible for only a small increase in mutations at known drug resistance sites and propose that concerns for increased resistance to other antiviral drugs should not prevent Vif from being considered a suitable target for development of new drugs.

  16. Vif proteins from diverse primate lentiviral lineages use the same binding site in APOBEC3G.

    Science.gov (United States)

    Letko, Michael; Silvestri, Guido; Hahn, Beatrice H; Bibollet-Ruche, Frederick; Gokcumen, Omer; Simon, Viviana; Ooms, Marcel

    2013-11-01

    APOBEC3G (A3G) is a cytidine deaminase that restricts human immunodeficiency virus type 1 (HIV-1) and other lentiviruses. Most of these viruses encode a Vif protein that directly binds A3G and leads to its proteasomal degradation. Both Vif proteins of HIV-1 and African green monkey simian immunodeficiency virus (SIVagm) bind residue 128 of A3G. However, this position does not control the A3G degradation by Vif variants derived from HIV-2 and SIVmac, which both originated from SIV of sooty mangabey monkeys (SIVsmm), suggesting that the A3G binding site for Vif proteins of the SIVsmm/HIV-2 lineage differs from that of HIV-1. To map the SIVsmm Vif binding site of A3G, we performed immunoprecipitations of individual A3G domains, Vif/A3G degradation assays and a detailed mutational analysis of human A3G. We show that A3G residue 129, but not the adjacent position 128, confers susceptibility to degradation by SIVsmm Vif. An artificial A3G mutant, the P129D mutant, was resistant to degradation by diverse Vifs from HIV-1, HIV-2, SIVagm, and chimpanzee SIV (SIVcpz), suggesting a conserved lentiviral Vif binding site. Gorilla A3G naturally contains a glutamine (Q) at position 129, which makes its A3G resistant to Vifs from diverse lineages. We speculate that gorilla A3G serves as a barrier against SIVcpz strains. In summary, we show that Vif proteins from distinct lineages bind to the same A3G loop, which includes positions 128 and 129. The multiple adaptations within this loop among diverse primates underscore the importance of counteracting A3G in lentiviral evolution.

  17. 新型抗病毒因子APOBEC3G研究进展

    Institute of Scientific and Technical Information of China (English)

    褚小刚; 杨占秋; 龚作炯

    2006-01-01

    APOBEC3G是一种天然抗病毒活性的胞嘧啶脱氨基酶家族成员,近年来因其独特的抗病毒作用机制受到了广泛的关注.在艾滋病病毒(HIV)复制过程中,APOBEC3G大量包装进入新生成的病毒颗粒内部,诱导病毒负链cDNA胞嘧啶(C)脱氨基突变为尿嘧啶(U),导致病毒丧失活性.而HIV编码的Vif蛋白能拮抗APOBEC3G的脱氨基酶作用,二者形成动态平衡.作为一种机体天然抗病毒因子,APOBEC3G参与了宿主抵抗HIV入侵的防御机制,为新型抗病毒药物的开发和机体天然免疫机制的研究开拓了新的方向,可能对未来的HIV及其他病毒性疾病的防治提供新的线索并产生重要的影响.

  18. Natural variation in Vif: differential impact on APOBEC3G/3F and a potential role in HIV-1 diversification.

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    Viviana Simon

    2005-09-01

    Full Text Available The HIV-1 Vif protein counteracts the antiviral activity exhibited by the host cytidine deaminases APOBEC3G and APOBEC3F. Here, we show that defective vif alleles can readily be found in HIV-1 isolates and infected patients. Single residue changes in the Vif protein sequence are sufficient to cause the loss of Vif-induced APOBEC3 neutralization. Interestingly, not all the detected defects lead to a complete inactivation of Vif function since some mutants retained selective neutralizing activity against APOBEC3F but not APOBEC3G or vice versa. Concordantly, independently hypermutated proviruses with distinguishable patterns of G-to-A substitution attributable to cytidine deamination induced by APOBEC3G, APOBEC3F, or both enzymes were present in individuals carrying proviruses with completely or partly defective Vif variants. Natural variation in Vif function may result in selective and partial neutralization of cytidine deaminases and thereby promote viral sequence diversification within HIV-1 infected individuals.

  19. Natural Variation in Vif: Differential Impact on APOBEC3G/3F and a Potential Role in HIV-1 Diversification.

    Directory of Open Access Journals (Sweden)

    2005-09-01

    Full Text Available The HIV-1 Vif protein counteracts the antiviral activity exhibited by the host cytidine deaminases APOBEC3G and APOBEC3F. Here, we show that defective vif alleles can readily be found in HIV-1 isolates and infected patients. Single residue changes in the Vif protein sequence are sufficient to cause the loss of Vif-induced APOBEC3 neutralization. Interestingly, not all the detected defects lead to a complete inactivation of Vif function since some mutants retained selective neutralizing activity against APOBEC3F but not APOBEC3G or vice versa. Concordantly, independently hypermutated proviruses with distinguishable patterns of G-to-A substitution attributable to cytidine deamination induced by APOBEC3G, APOBEC3F, or both enzymes were present in individuals carrying proviruses with completely or partly defective Vif variants. Natural variation in Vif function may result in selective and partial neutralization of cytidine deaminases and thereby promote viral sequence diversification within HIV-1 infected individuals.

  20. APOBEC3G impairs the multimerization of the HIV-1 Vif protein in living cells.

    Science.gov (United States)

    Batisse, Julien; Guerrero, Santiago Xavier; Bernacchi, Serena; Richert, Ludovic; Godet, Julien; Goldschmidt, Valérie; Mély, Yves; Marquet, Roland; de Rocquigny, Hugues; Paillart, Jean-Christophe

    2013-06-01

    The HIV-1 viral infectivity factor (Vif) is a small basic protein essential for viral fitness and pathogenicity. Vif allows productive infection in nonpermissive cells, including most natural HIV-1 target cells, by counteracting the cellular cytosine deaminases APOBEC3G (apolipoprotein B mRNA-editing enzyme catalytic polypeptide-like 3G [A3G]) and A3F. Vif is also associated with the viral assembly complex and packaged into viral particles through interactions with the viral genomic RNA and the nucleocapsid domain of Pr55(Gag). Recently, we showed that oligomerization of Vif into high-molecular-mass complexes induces Vif folding and influences its binding to high-affinity RNA binding sites present in the HIV genomic RNA. To get further insight into the role of Vif multimerization in viral assembly and A3G repression, we used fluorescence lifetime imaging microscopy (FLIM)- and fluorescence resonance energy transfer (FRET)-based assays to investigate Vif-Vif interactions in living cells. By using two N-terminally tagged Vif proteins, we show that Vif-Vif interactions occur in living cells. This oligomerization is strongly reduced when the putative Vif multimerization domain ((161)PPLP(164)) is mutated, indicating that this domain is crucial, but that regions outside this motif also participate in Vif oligomerization. When coexpressed together with Pr55(Gag), Vif is largely relocated to the cell membrane, where Vif oligomerization also occurs. Interestingly, wild-type A3G strongly interferes with Vif multimerization, contrary to an A3G mutant that does not bind to Vif. These findings confirm that Vif oligomerization occurs in living cells partly through its C-terminal motif and suggest that A3G may target and perturb the Vif oligomerization state to limit its functions in the cell.

  1. Random mutagenesis MAPPIT analysis identifies binding sites for Vif and Gag in both cytidine deaminase domains of Apobec3G.

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    Isabel Uyttendaele

    Full Text Available The mammalian two-hybrid system MAPPIT allows the detection of protein-protein interactions in intact human cells. We developed a random mutagenesis screening strategy based on MAPPIT to detect mutations that disrupt the interaction of one protein with multiple protein interactors simultaneously. The strategy was used to detect residues of the human cytidine deaminase Apobec3G that are important for its homodimerization and its interaction with the HIV-1 Gag and Vif proteins. The strategy is able to identify the previously described head-to-head homodimerization interface in the N-terminal domain of Apobec3G. Our analysis further detects two new potential interaction surfaces in the N-and C-terminal domain of Apobec3G for interaction with Vif and Gag or for Apobec3G dimerization.

  2. Analysis of the N-terminal positively charged residues of the simian immunodeficiency virus Vif reveals a critical amino acid required for the antagonism of rhesus APOBEC3D, G, and H.

    Science.gov (United States)

    Schmitt, Kimberly; Katuwal, Miki; Wang, Yaqiong; Li, Cicy; Stephens, Edward B

    2014-01-20

    Previous studies have shown that apolipoprotein B mRNA editing, enzyme catalytic, polypeptide G (APOBEC3G; hA3G) and F (APOBEC3F; hA3F) proteins interact with a nonlinear binding site located at the N-terminal region of the HIV-1 Vif protein. We have analyzed the role of 12 positively charged amino acids of the N-terminal region of the SIV Vif. Simian-human immunodeficiency viruses (SHIV) were constructed that expressed each of these amino acid substitutions. These viruses were examined for replication in the presence of rhesus macaque APOBEC3 proteins (rhA3A-rhA3H), incorporation of the different A3 proteins into virions, and replication in rhesus macaque PBMC. Similar to other studies, we found that K27 was essential for rhA3G activity and rhA3F but was not important for restriction of SHIVΔvif by rhA3A, rhA3D or rhA3H. Our results identified the arginine at position 14 of the SIV Vif as a critical residue for virus restriction by rhA3D, rhA3G and rhA3H.

  3. Production of infectious human immunodeficiency virus type 1 does not require depletion of APOBEC3G from virus-producing cells

    Directory of Open Access Journals (Sweden)

    Goila-Gaur Ritu

    2004-09-01

    Full Text Available Abstract Background The human immunodeficiency virus Vif protein overcomes the inhibitory activity of the APOBEC3G cytidine deaminase by prohibiting its packaging into virions. Inhibition of APOBEC3G encapsidation is paralleled by a reduction of its intracellular level presumably caused by the Vif-induced proteasome-dependent degradation of APOBEC3G. Results In this report we employed confocal microscopy to study the effects of Vif on the expression of APOBEC3G on a single cell level. HeLa cells dually transfected with Vif and APOBEC3G expression vectors revealed efficient co-expression of the two proteins. Under optimal staining conditions approximately 80% of the transfected cells scored double-positive for Vif and APOBEC3G. However, the proportion of double-positive cells observed in identical cultures varied dependent on the fixation protocol and on the choice of antibodies used ranging from as low as 40% to as high as 80% of transfected cells. Importantly, single-positive cells expressing either Vif or APOBEC3G were observed both with wild type Vif and a biologically inactive Vif variant. Thus, the lack of APOBEC3G in some Vif-expressing cells cannot be attributed to Vif-induced degradation of APOBEC3G. These findings are consistent with our results from immunoblot analyses that revealed only moderate effects of Vif on the APOBEC3G steady state levels. Of note, viruses produced under such conditions were fully infectious demonstrating that the Vif protein used in our analyses was both functional and expressed at saturating levels. Conclusions Our results suggest that Vif and APOBEC3G can be efficiently co-expressed. Thus, depletion of APOBEC3G from Vif expressing cells as suggested previously is not a universal property of Vif and thus is not imperative for the production of infectious virions.

  4. 基于Vif-APOBEC3G相互作用的抗HIV-1药物研究%Anti-HIV-1 agents based on Vif-APOBEC3G interaction: research advances

    Institute of Scientific and Technical Information of China (English)

    张兴杰; 王睿睿; 郑永唐

    2010-01-01

    载脂蛋白B mRNA编辑酶催化多肽样蛋白3G(apolipoprotein B mRNA-editing enzyme catalyticpolypeptidelike 3G,APOBEC3G或A3G)是人体天然抗病毒分子,可以使病毒逆转录形成的cDNA的胞嘧啶(C)脱氨为尿嘧啶(U),产生鸟嘌呤(G)→腺嘌呤(A)超突变,导致病毒转录产物突变,从而达到抑制病毒复制的作用.HIV-1的辅助蛋白Vif,可与APOBEC3G相互作用并导致其被降解,使得这一天然抗病毒机制失效,进而增强了HIV的感染力.Vif与APOBEC3G这种相互作用为抗HIV药物提供了新靶点.针对Vif-APOBEC3G相互作用的抗HIV抑制剂已经成为研究热点.本文综述了Vif和APOBEC3G的结构、二者的相互作用,以及基于这一相互作用的抗HIV-1抑制剂研究进展.

  5. The Binding Interface between Human APOBEC3F and HIV-1 Vif Elucidated by Genetic and Computational Approaches.

    Science.gov (United States)

    Richards, Christopher; Albin, John S; Demir, Özlem; Shaban, Nadine M; Luengas, Elizabeth M; Land, Allison M; Anderson, Brett D; Holten, John R; Anderson, John S; Harki, Daniel A; Amaro, Rommie E; Harris, Reuben S

    2015-12-01

    APOBEC3 family DNA cytosine deaminases provide overlapping defenses against pathogen infections. However, most viruses have elaborate evasion mechanisms such as the HIV-1 Vif protein, which subverts cellular CBF-β and a polyubiquitin ligase complex to neutralize these enzymes. Despite advances in APOBEC3 and Vif biology, a full understanding of this direct host-pathogen conflict has been elusive. We combine virus adaptation and computational studies to interrogate the APOBEC3F-Vif interface and build a robust structural model. A recurring compensatory amino acid substitution from adaptation experiments provided an initial docking constraint, and microsecond molecular dynamic simulations optimized interface contacts. Virus infectivity experiments validated a long-lasting electrostatic interaction between APOBEC3F E289 and HIV-1 Vif R15. Taken together with mutagenesis results, we propose a wobble model to explain how HIV-1 Vif has evolved to bind different APOBEC3 enzymes and, more generally, how pathogens may evolve to escape innate host defenses.

  6. Prokaryotic Expression and Purification of HIV-1 Vif and hAPOBEC3G, Preparation of Polyclonal Antibodies

    Institute of Scientific and Technical Information of China (English)

    Lan LI; Yi-shu YANG; Ze-lin LI; Yi ZENG

    2008-01-01

    To prepare HIV-1 Vif and hAPOBEC3G and to produce their antibodies, the full length gene fragment of HIV-1 Vif was amplified by PCR from a plasmid of HIV-1 NL4.3 cDNA, and the APOBEC3G gene was obtained by RT-PCR from the total RNA of H9 cells. The resulting DNA construct was cloned into a prokaryotic expression vector (pET-32a). Recombinant pET-vif and pET-APOBEC3G were expressed respectively in Eserichia coli BL21 (DE3) as an insoluble protein. The vector also contained a six-histidine tag at the C-terminus for convenient purification and detection. To express and purify the HIV-1 Vif and hAPOBEC3G in E. coli cells, the accuracy of inserted gene and specificity of proteins were detected by the two enzyme digestion method, SDS-PAGE, and Western blotting. Rabbits were then immunized by Vif or APOBEC3G protein and serum samples were tested by indirect ELISA to determine the level of antibodies. Immunoenzyme and immunofluorescence assays were performed to identify the specificity of polyclonal antibodies. The titer of the anti-Vif antibodies was 1:204800, and that of the anti-APOBEC3G antibodies was 1:102400. Thus the antibodies could detect the antigen expression in the cells, demonstrating that fusion proteins with high purity and their corresponding polyclonal antibodies with high titer and specificity were achieved.

  7. APOBEC3G和HIV-1病毒感染因子Vif研究最新进展

    Institute of Scientific and Technical Information of China (English)

    张文俊; 乔新华; 李泽琳; 曾毅

    2012-01-01

    固有免疫在机体抵御HIV-1感染过程中发挥重要作用.载脂蛋白B mRNA编辑酶催化多肽样蛋白(apolipoprotein B mRNA-editing enzyme catalytic polypeptide protein,APOBEC)家族的成员APOBEC3G(A3G)可以通过胞嘧啶脱氨机制抑制HIV-1的复制,发挥固有免疫的作用;病毒感染因子(virus infectivity factor,Vif)能与A3G结合并引发A3G的降解,使HIV-1的感染率增加100倍以上.该研究为以Vif-A3G为靶点的抗HIV-1药物的研究提供了新的思路.因此A3G、Vif及其相互作用机制成为HIV-1研究的热点.

  8. HIV-1 Vpr促进Vif和APOBEC3G蛋白表达的研究%Enhanced protein production of Vif and APOBEC3G by HIV-1 Vpr

    Institute of Scientific and Technical Information of China (English)

    李林; 梁栋; 李敬云; 赵玉琪

    2008-01-01

    目的 观察人获得性免疫缺陷病毒蛋白Vpr对Vif蛋白和APOBEC3G蛋白表达水平的影响.方法 使用电转化法将携带Vif基因的酵母表达载体转化到裂殖酵母中,使用脂质体转染法将表达Vif蛋白、APOBEC3G蛋白的哺乳动物表达载体转染到可诱导稳定表达Vpr蛋白的哺乳动物HEK293细胞中;使用Western Blot方法检测目标蛋白表达水平的变化.结果 在裂殖酵母和哺乳动物细胞中,Vpr蛋白的表达能够提高细胞内的Vif蛋白的表达水平,在哺乳动物细胞中,Vpr蛋白对APOBEC3G蛋白的表达亦有促进作用,Vpr蛋白引起的Vif蛋白量的提高并没有导致APOBEC3G蛋白的减少.结论 Vpr蛋白具有调节细胞内蛋白表达的功能.

  9. Vpr14-88-Apobec3G fusion protein is efficiently incorporated into Vif-positive HIV-1 particles and inhibits viral infection.

    Directory of Open Access Journals (Sweden)

    Zhujun Ao

    Full Text Available BACKGROUND: APOBEC3G (A3G, a deoxycytidine deaminase, is a potent host antiviral factor that can restrict HIV-1 infection. During Vif-negative HIV-1 replication, A3G is incorporated into HIV-1 particles, induces mutations in reverse transcribed viral DNA and inhibits reverse transcription. However, HIV-1 Vif counteracts A3G's activities by inducing its degradation and by blocking its incorporation into HIV-1 particles. Thus, it is interesting to elucidate a mechanism that would allow A3G to escape the effects of Vif in order to rescue its potent antiviral activity and to provide a possible novel therapeutic strategy for treating HIV-1 infection. METHODS AND FINDINGS: In this study, we generated an R88-A3G fusion protein by fusing A3G to a virion-targeting polypeptide (R14-88 derived from HIV-1 Vpr protein and compared its antiviral effects relative to those of HA-tagged native A3G (HA-A3G. Our study showed that transient expression of the R88-A3G fusion protein in both Vif(- and Vif(+ HIV-1 producing cells drastically inhibited viral infection in HeLa-CD4-CCR5-cells, CD4(+ C8166 T cells and human primary PBMCs. Moreover, we established CD4(+ C8166 T cell lines that stably express either R88-A3G or HA-A3G by transduction with VSV-G-pseudotyped lentiviral vector that harbor expression cassettes for R88-A3G or HA-A3G, respectively, and tested their susceptibility to Vif(+ HIV-1 infection. Our results clearly reveal that expression of R88-A3G in transduced CD4(+ C8166 cells significantly blocked Vif(+ HIV-1 infection. In an attempt to understand the mechanism underlying the antiviral activity of R88-A3G, we demonstrated that R88-A3G was efficiently incorporated into viral particles in the presence of Vif. Moreover, PCR analysis revealed that R88-A3G significantly inhibited viral cDNA synthesis during the early stage of Vif(+ virus infection. CONCLUSIONS: Our results clearly indicate that R88 delivers A3G into Vif(+ HIV-1 particles and inhibits

  10. Human APOBEC3G-mediated hypermutation is associated with antiretroviral therapy failure in HIV-1 subtype C-infected individuals

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    Anita Shet

    2013-02-01

    Full Text Available Introduction: Human APOBEC3G/F (hA3G/F restricts retroviral replication through G-to-A hypermutations, which can generate drug-resistant progenies in vitro. The clinical relevance is still inconclusive. To bridge this gap, we aim to study the role of these hypermutations in evolution of drug resistance; we characterised hA3G/F-mediated hypermutations in the RT region of the pol gene of patients with or without antiretroviral therapy (ART. Methods: In 88 HIV-1-positive individuals, drug resistance genotyping was carried out in plasma virus and provirus by population sequencing. Hypermutations were determined by three different approaches using Hypermut 2.0 software, cluster analysis and APOBEC3G-mediated defectives indices. Clinical and demographic characteristics of these individuals were studied in relation to these hypermutations. Results: hA3G/F-mediated hypermutated sequences in proviral DNA, but not in plasma virus, were identified in 11.4% (10/88 subjects. Proviral hypermutations were observed more frequently in patients with ART failure than in ART-naïve individuals (p=0.03. In therapy failure patients, proviral hypermutation were associated with greater intra-compartmental genetic diversity (p<0.001. In therapy-naïve individuals, hypermutated proviral DNA with M184I and M230I mutations due to the editing of hA3G, had stop codons in the open reading frames and the same mutations were absent in the plasma virus. Only a limited concordance was found between the drug resistance mutations in plasma RNA and proviral DNA. Conclusions: hA3G lethal hypermutation was significantly associated with ART failure in Indian HIV-1 subtype C patients. It is unlikely that viral variants, which exhibit hypermutated sequences and M184I and/or M230I, will mature and expand in vivo.

  11. Identification of a novel HIV-1 inhibitor targeting Vif-dependent degradation of human APOBEC3G protein.

    Science.gov (United States)

    Pery, Erez; Sheehy, Ann; Nebane, N Miranda; Brazier, Andrew Jay; Misra, Vikas; Rajendran, Kottampatty S; Buhrlage, Sara J; Mankowski, Marie K; Rasmussen, Lynn; White, E Lucile; Ptak, Roger G; Gabuzda, Dana

    2015-04-17

    APOBEC3G (A3G) is a cellular cytidine deaminase that restricts HIV-1 replication by inducing G-to-A hypermutation in viral DNA and by deamination-independent mechanisms. HIV-1 Vif binds to A3G, resulting in its degradation via the 26 S proteasome. Therefore, this interaction represents a potential therapeutic target. To identify compounds that inhibit interaction between A3G and HIV-1 Vif in a high throughput format, we developed a homogeneous time-resolved fluorescence resonance energy transfer assay. A 307,520 compound library from the NIH Molecular Libraries Small Molecule Repository was screened. Secondary screens to evaluate dose-response performance and off-target effects, cell-based assays to identify compounds that attenuate Vif-dependent degradation of A3G, and assays testing antiviral activity in peripheral blood mononuclear cells and T cells were employed. One compound, N.41, showed potent antiviral activity in A3G(+) but not in A3G(-) T cells and had an IC50 as low as 8.4 μM and a TC50 of >100 μM when tested against HIV-1Ba-L replication in peripheral blood mononuclear cells. N.41 inhibited the Vif-A3G interaction and increased cellular A3G levels and incorporation of A3G into virions, thereby attenuating virus infectivity in a Vif-dependent manner. N.41 activity was also species- and Vif-dependent. Preliminary structure-activity relationship studies suggest that a hydroxyl moiety located at a phenylamino group is critical for N.41 anti-HIV activity and identified N.41 analogs with better potency (IC50 as low as 4.2 μM). These findings identify a new lead compound that attenuates HIV replication by liberating A3G from Vif regulation and increasing its innate antiviral activity.

  12. APOBEC3B-Mediated Cytidine Deamination Is Required for Estrogen Receptor Action in Breast Cancer

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    Manikandan Periyasamy

    2015-10-01

    Full Text Available Estrogen receptor α (ERα is the key transcriptional driver in a large proportion of breast cancers. We report that APOBEC3B (A3B is required for regulation of gene expression by ER and acts by causing C-to-U deamination at ER binding regions. We show that these C-to-U changes lead to the generation of DNA strand breaks through activation of base excision repair (BER and to repair by non-homologous end-joining (NHEJ pathways. We provide evidence that transient cytidine deamination by A3B aids chromatin modification and remodelling at the regulatory regions of ER target genes that promotes their expression. A3B expression is associated with poor patient survival in ER+ breast cancer, reinforcing the physiological significance of A3B for ER action.

  13. A hydrodynamic analysis of APOBEC3G reveals a monomer-dimer-tetramer self-association that has implications for anti-HIV function.

    Science.gov (United States)

    Salter, Jason D; Krucinska, Jolanta; Raina, Jay; Smith, Harold C; Wedekind, Joseph E

    2009-11-17

    The innate antiviral factor APOBEC3G (A3G) possesses RNA binding activity and deaminates HIV-1 DNA. High-molecular mass forms of A3G can be isolated from a variety of cell types but exhibit limited deaminase activity relative to low-molecular mass species prepared under RNA-depleted conditions. To investigate the fundamental oligomeric state and shape of A3G, we conducted sedimentation velocity analyses of the pure enzyme under RNA-deficient conditions. The results reveal a predominant dimer in equilibrium with minor monomeric and tetrameric species. Hydrodynamic modeling of the dimer supports an extended cylindrical shape that assembles into an elongated tetramer. Overall, the results provide physical restraints for the A3G quaternary structure that have implications for modulating antiviral function.

  14. Real Moments of the Restrictive Factor

    Indian Academy of Sciences (India)

    Andrew Ledoan; Alexandru Zaharescu

    2009-09-01

    Let be a real number such that 0 < < 1. We establish asymptotic formulas for the weighted real moments $\\sum_{n≤ x}R^(n)(1-n/x)$, where $R(n)=\\prod^k_{v=1}p^{ v-1}_v$ is the Atanassov strong restrictive factor function and $n=\\prod^k_{v=1}p^{ v}_v$ is the prime factorization of .

  15. Catalytic analysis of APOBEC3G involving real-time NMR spectroscopy reveals nucleic acid determinants for deamination.

    Directory of Open Access Journals (Sweden)

    Keisuke Kamba

    Full Text Available APOBEC3G (A3G is a single-stranded DNA-specific cytidine deaminase that preferentially converts cytidine to uridine at the third position of triplet cytosine (CCC hotspots. A3G restricts the infectivity of viruses, such as HIV-1, by targeting CCC hotspots scattered through minus DNA strands, reverse-transcribed from genomic RNA. Previously, we developed a real-time NMR method and elucidated the origin of the 3'→5' polarity of deamination of DNA by the C-terminal domain of A3G (CD2, which is a phenomenon by which a hotspot located closer to the 5'-end is deaminated more effectively than one less close to the 5'-end, through quantitative analysis involving nonspecific binding to and sliding along DNA. In the present study we applied the real-time NMR method to analyze the catalytic activity of CD2 toward DNA oligonucleotides containing a nucleotide analog at a single or multiple positions. Analyses revealed the importance of the sugar and base moieties throughout the consecutive 5 nucleotides, the CCC hotspot being positioned at the center. It was also shown that the sugar or base moieties of the nucleotides outside this 5 nucleotide recognition sequence are also relevant as to CD2's activity. Analyses involving DNA oligonucleotides having two CCC hotspots linked by a long sequence of either deoxyribonucleotides, ribonucleotides or abasic deoxyribonucleotides suggested that the phosphate backbone is required for CD2 to slide along the DNA strand and to exert the 3'→5' polarity. Examination of the effects of different salt concentrations on the 3'→5' polarity indicated that the higher the salt concentration, the less prominent the 3'→5' polarity. This is most likely the result of alleviation of sliding due to a decrease in the affinity of CD2 with the phosphate backbone at high salt concentrations. We also investigated the reactivity of substrates containing 5-methylcytidine (5mC or 5-hydroxymethylcytidine, and found that A3G exhibited low

  16. B-Myb Induces APOBEC3B Expression Leading to Somatic Mutation in Multiple Cancers

    Science.gov (United States)

    Chou, Wen-Cheng; Chen, Wei-Ting; Hsiung, Chia-Ni; Hu, Ling-Yueh; Yu, Jyh-Cherng; Hsu, Huan-Ming; Shen, Chen-Yang

    2017-01-01

    The key signature of cancer genomes is the accumulation of DNA mutations, the most abundant of which is the cytosine-to-thymine (C-to-T) transition that results from cytosine deamination. Analysis of The Cancer Genome Atlas (TCGA) database has demonstrated that this transition is caused mainly by upregulation of the cytosine deaminase APOBEC3B (A3B), but the mechanism has not been completely characterized. We found that B-Myb (encoded by MYBL2) binds the A3B promoter, causing transactivation, and this is responsible for the C-to-T transitions and DNA hypermutation in breast cancer cells. Analysis of TCGA database yielded similar results, supporting that MYBL2 and A3B are upregulated and putatively promote C-to-T transitions in multiple cancer types. Moreover, blockade of EGF receptor with afatinib attenuated B-Myb–A3B signaling, suggesting a clinically relevant means of suppressing mutagenesis. Our results suggest that B-Myb–A3B contributes to DNA damage and could be targeted by inhibiting EGF receptor. PMID:28276478

  17. Targeting APOBEC3A to the viral nucleoprotein complex confers antiviral activity

    Directory of Open Access Journals (Sweden)

    Strebel Klaus

    2007-08-01

    Full Text Available Abstract Background APOBEC3 (A3 proteins constitute a family of cytidine deaminases that provide intracellular resistance to retrovirus replication and to transposition of endogenous retroelements. A3A has significant homology to the C-terminus of A3G but has only a single cytidine deaminase active site (CDA, unlike A3G, which has a second N-terminal CDA previously found to be important for Vif sensitivity and virus encapsidation. A3A is packaged into HIV-1 virions but, unlike A3G, does not have antiviral properties. Here, we investigated the reason for the lack of A3A antiviral activity. Results Sequence alignment of A3G and A3A revealed significant homology of A3A to the C-terminal region of A3G. However, while A3G co-purified with detergent-resistant viral nucleoprotein complexes (NPC, virus-associated A3A was highly detergent-sensitive leading us to speculate that the ability to assemble into NPC may be a property conveyed by the A3G N-terminus. To test this model, we constructed an A3G-3A chimeric protein, in which the N-terminal half of A3G was fused to A3A. Interestingly, the A3G-3A chimera was packaged into HIV-1 particles and, unlike A3A, associated with the viral NPC. Furthermore, the A3G-3A chimera displayed strong antiviral activity against HIV-1 and was sensitive to inhibition by HIV-1 Vif. Conclusion Our results suggest that the A3G N-terminal domain carries determinants important for targeting the protein to viral NPCs. Transfer of this domain to A3A results in A3A targeting to viral NPCs and confers antiviral activity.

  18. Mutation Processes in 293-Based Clones Overexpressing the DNA Cytosine Deaminase APOBEC3B.

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    Monica K Akre

    Full Text Available Molecular, cellular, and clinical studies have combined to demonstrate a contribution from the DNA cytosine deaminase APOBEC3B (A3B to the overall mutation load in breast, head/neck, lung, bladder, cervical, ovarian, and other cancer types. However, the complete landscape of mutations attributable to this enzyme has yet to be determined in a controlled human cell system. We report a conditional and isogenic system for A3B induction, genomic DNA deamination, and mutagenesis. Human 293-derived cells were engineered to express doxycycline-inducible A3B-eGFP or eGFP constructs. Cells were subjected to 10 rounds of A3B-eGFP exposure that each caused 80-90% cell death. Control pools were subjected to parallel rounds of non-toxic eGFP exposure, and dilutions were done each round to mimic A3B-eGFP induced population fluctuations. Targeted sequencing of portions of TP53 and MYC demonstrated greater mutation accumulation in the A3B-eGFP exposed pools. Clones were generated and microarray analyses were used to identify those with the greatest number of SNP alterations for whole genome sequencing. A3B-eGFP exposed clones showed global increases in C-to-T transition mutations, enrichments for cytosine mutations within A3B-preferred trinucleotide motifs, and more copy number aberrations. Surprisingly, both control and A3B-eGFP clones also elicited strong mutator phenotypes characteristic of defective mismatch repair. Despite this additional mutational process, the 293-based system characterized here still yielded a genome-wide view of A3B-catalyzed mutagenesis in human cells and a system for additional studies on the compounded effects of simultaneous mutation mechanisms in cancer cells.

  19. HIV-1 Gag-virus-like particles inhibit HIV-1 replication in dendritic cells and T cells through IFN-α-dependent upregulation of APOBEC3G and 3F.

    Science.gov (United States)

    Chang, Myint Oo; Suzuki, Tomoyuki; Yamamoto, Norio; Watanabe, Megumi; Takaku, Hiroshi

    2012-01-01

    Human immunodeficiency virus-1 (HIV-1) infection and the acquired immune deficiency syndrome (AIDS) pandemic remain global threats in the absence of a protective or a therapeutic vaccine. HIV-1 replication is reportedly inhibited by some cellular factors, including APOBEC3G (A3G) and APOBEC3F (A3F), which are well known inhibitors of HIV-1. Recently, HIV-1 Gag-virus-like particles (Gag-VLPs) have been shown to be safe and potent HIV-1 vaccine candidates that can elicit strong cellular and humoral immunity without need of any adjuvant. In this report, we stimulated human monocyte-derived dendritic cells (DCs) with Gag-VLPs and we demonstrated that Gag-VLP-treated DCs (VLP-DCs) produced interferon alpha (IFN-α), along with an increase in mRNA and protein expression of A3G and A3F. Gag-VLPs inhibited HIV-1 replication not only in DCs themselves, but also in cocultured T cells in an IFN-α-dependent manner. In addition, A3G/3F content in HIV virions released from VLP-DCs increased. Both the increase in A3G/3F expression and the inhibition of HIV-1 replication were reversed by anti-IFN-α or anti-IFNAR antibodies. Our findings in this study provide insight into the mechanism of Gag-VLP-induced inhibition of HIV-1 replication in DCs and T cells.

  20. Association of Hepatitis B Virus Covalently Closed Circular DNA and Human APOBEC3B in Hepatitis B Virus-Related Hepatocellular Carcinoma.

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    Xuan Luo

    Full Text Available Chronic Hepatitis B Virus (HBV infections can progresses to liver cirrhosis and hepatocellular carcinoma (HCC. The HBV covalently-closed circular DNA cccDNA is a key to HBV persistence, and its degradation can be induced by the cellular deaminase APOBEC3. This study aimed to measure the distribution of intrahepatic cccDNA levels and evaluate the association between levels of cccDNA and APOBEC3 in HCC patients. Among 49 HCC patients, 35 matched cancerous and contiguous noncancerous liver tissues had detectable cccDNA, and the median intrahepatic cccDNA in the cancerous tissues (CT was significantly lower than in the contiguous noncancerous tissues (CNCT (p = 0.0033. RCA (rolling circle amplification, followed by 3D-PCR identified positive amplification in 27 matched HCC patients. Sequence analysis indicated G to A mutations accumulated to higher levels in CT samples compared to CNCT samples, and the dinucleotide context showed preferred editing in the GpA context. Among 7 APOBEC3 genes, APOBEC3B was the only one up-regulated in cancerous tissues both at the transcriptional and protein levels (p < 0.05. This implies APOBEC3B may contribute to cccDNA editing and subsequent degradation in cancerous tissues.

  1. Association of single nucleotide polymorphisms of APOBEC3G with susceptibility to HIV-1 infection and disease progression among men engaging in homosexual activity in northern China.

    Science.gov (United States)

    Li, Qiuyan; Qiao, Yuandong; Zhang, Guangfa; He, Ning; Zhang, Xuelong; Jia, Xueyuan; Sun, Haiming; Wang, Chuntao; Xu, Lidan

    2017-01-01

    Men who have sex with men (MSM) are at high risk of HIV infection. The APOBEC3G (apolipoprotein B mRNA editing catalytic polypeptide 3G) protein is a component of innate antiviral immunity that inhibits HIV-1 replication. In the present study, a total of 483 HIV-1 seropositive men and 493 HIV-1 seronegative men were selected to investigate the association between single nucleotide polymorphisms (SNPs) of the APOBEC3G gene and susceptibility to HIV-1 infection and AIDS progression among MSM residing in northern China. Genotyping of four SNPs (rs5757465, rs3736685, rs8177832, and rs2899313) of the APOBEC3G was performed using the SNPscan™ Kit, while the rs2294367 polymorphism was genotyped using the SNaPshot multiplex system. Our results disclosed no association between the SNPs of APOBEC3G and susceptibility to HIV-1, or effects of these polymorphisms on the CD4(+) T cell count or clinical phase of disease. A meta-analysis of 1624 men with HIV-1 infection and 1523 controls suggested that the association between rs8177832 and susceptibility was not significant. However, we observed a trend towards association with HIV-1 infection for haplotype TTACA (p = 0.082). The potential role of variants of APOBEC3G in HIV-1/AIDS warrants further investigation.

  2. A naturally occurring Vif mutant (I107T) attenuates anti-APOBEC3G activity and HIV-1 replication.

    Science.gov (United States)

    Peng, Jinyu; Ao, Zhujun; Matthews, Chris; Wang, Xiaoxia; Ramdahin, Sue; Chen, Xi; Li, Junhua; Chen, Liyu; He, Jianmei; Ball, Blake; Fowke, Keith; Plummer, Frank; Embree, Joanne; Yao, Xiaojian

    2013-08-23

    The human immunodeficiency virus type 1 (HIV-1) Vif protein counteracts the antiviral activity of the apolipoprotein B mRNA editing enzyme catalytic polypeptide-like 3 (APOBEC3) family of proteins by targeting the proteins for degradation through the ubiquitin-proteasome pathway. Previous mutagenic studies have shown that multiple domains of Vif are required for interacting with APOBEC3G proteins and the proteasome pathway. However, very few mutagenesis and functional analyses of patient-derived Vif proteins have been conducted. In this study, we amplified and cloned the HIV-1 vif genes from the peripheral blood mononuclear cells (PBMCs) of five HIV-1-infected individuals in Nairobi and further tested the impact of the genes on anti-A3G activity and HIV-1 replication. The gene sequence analysis revealed high genetic variation of vif genes from different HIV-1-infected individuals. Interestingly, the Vif proteins derived from two of the three long-term survivors (LTSs) displayed a significantly impaired ability to mediate the degradation of A3G. In particular, a single amino acid change (I107T) in one of the non-functional LTS Vif variants, which has not been previously identified in the Los Alamos databases of vif sequences, was found to be responsible for the lack of anti-A3G activity. Further study demonstrated that HIV-1 carrying an I107T Vif mutation displayed significantly reduced fitness in A3G(+) T cells and PBMCs. Moreover, co-infecting A3G(+) T cells with both the wild-type and I107T Vif viruses resulted in decreased viral replication. Overall, the results of this study indicate that the HIV-1 Vif residue I107 is important for its anti-APOBEC3G activity and viral replication, which may have implications for viral fitness in vivo.

  3. Induction of heat-shock protein 70 by prostaglandin A₁ inhibits HIV-1 Vif-mediated degradation of APOBEC3G.

    Science.gov (United States)

    Sugiyama, Ryuichi; Abe, Makoto; Nishitsuji, Hironori; Murakami, Yuko; Takeuchi, Hiroaki; Takaku, Hiroshi

    2013-09-01

    Previous studies have demonstrated that cyclopentenone prostaglandins (cyPGs) inhibit human immunodeficiency virus type 1 (HIV-1) replication in various cell types. This antiviral activity has been associated with the induction of heat-shock protein 70 (HSP70) in infected cells. We investigated a new role of prostaglandin A₁ (PGA₁) in the replication of HIV-1 in non-permissive cells. Because overexpression of HSP70 blocks the viral infectivity factor (Vif)-mediated degradation of APOBEC3G (A3G) via the ubiquitin-proteasome pathway, we examined the effects of PGA₁ on A3G and HIV-1 replication. The induction of HSP70 synthesis by PGA₁ blocked Vif-mediated A3G degradation and enhanced the incorporation of A3G into both wild-type and Vif-deficient viruses. Furthermore, we determined the viral titer of HIV-1 particles produced from PGA₁-treated 293T cells. The induction of HSP70 synthesis by PGA₁ significantly reduced the viral titer in the presence of A3G. Additionally, the p24 Gag antigen levels were dramatically reduced in non-permissive cells treated once or repeatedly with PGA₁. Thus, we showed that PGA₁ inhibits HIV-1 replication, at least in part, by blocking Vif-mediated A3G degradation.

  4. Translational regulation of APOBEC3G mRNA by Vif requires its 5'UTR and contributes to restoring HIV-1 infectivity.

    Science.gov (United States)

    Guerrero, Santiago; Libre, Camille; Batisse, Julien; Mercenne, Gaëlle; Richer, Delphine; Laumond, Géraldine; Decoville, Thomas; Moog, Christiane; Marquet, Roland; Paillart, Jean-Christophe

    2016-12-20

    The essential HIV-1 viral infectivity factor (Vif) allows productive infection of non-permissive cells expressing cytidine deaminases APOBEC3G (A3G) and A3F by decreasing their cellular level, and preventing their incorporation into virions. Unlike the Vif-induced degradation of A3G, the functional role of the inhibition of A3G translation by Vif remained unclear. Here, we show that two stem-loop structures within the 5'-untranslated region of A3G mRNA are crucial for translation inhibition by Vif in cells, and most Vif alleles neutralize A3G translation efficiently. Interestingly, K26R mutation in Vif abolishes degradation of A3G by the proteasome but has no effect at the translational level, indicating these two pathways are independent. These two mechanisms, proteasomal degradation and translational inhibition, similarly contribute to decrease the cellular level of A3G by Vif and to prevent its incorporation into virions. Importantly, inhibition of A3G translation is sufficient to partially restore viral infectivity in the absence of proteosomal degradation. These findings demonstrate that HIV-1 has evolved redundant mechanisms to specifically inhibit the potent antiviral activity of A3G.

  5. APOBEC3G induces a hypermutation gradient: purifying selection at multiple steps during HIV-1 replication results in levels of G-to-A mutations that are high in DNA, intermediate in cellular viral RNA, and low in virion RNA

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    Pathak Vinay K

    2009-02-01

    Full Text Available Abstract Background Naturally occurring Vif variants that are unable to inhibit the host restriction factor APOBEC3G (A3G have been isolated from infected individuals. A3G can potentially induce G-to-A hypermutation in these viruses, and hypermutation could contribute to genetic variation in HIV-1 populations through recombination between hypermutant and wild-type genomes. Thus, hypermutation could contribute to the generation of immune escape and drug resistant variants, but the genetic contribution of hypermutation to the viral evolutionary potential is poorly understood. In addition, the mechanisms by which these viruses persist in the host despite the presence of A3G remain unknown. Results To address these questions, we generated a replication-competent HIV-1 Vif mutant in which the A3G-binding residues of Vif, Y40RHHY44, were substituted with five alanines. As expected, the mutant was severely defective in an A3G-expressing T cell line and exhibited a significant delay in replication kinetics. Analysis of viral DNA showed the expected high level of G-to-A hypermutation; however, we found substantially reduced levels of G-to-A hypermutation in intracellular viral RNA (cRNA, and the levels of G-to-A mutations in virion RNA (vRNA were even further reduced. The frequencies of hypermutation in DNA, cRNA, and vRNA were 0.73%, 0.12%, and 0.05% of the nucleotides sequenced, indicating a gradient of hypermutation. Additionally, genomes containing start codon mutations and early termination codons within gag were isolated from the vRNA. Conclusion These results suggest that sublethal levels of hypermutation coupled with purifying selection at multiple steps during the early phase of viral replication lead to the packaging of largely unmutated genomes, providing a mechanism by which mutant Vif variants can persist in infected individuals. The persistence of genomes containing mutated gag genes despite this selection pressure indicates that dual

  6. Parental factors associated with intrauterine growth restriction

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    Hăşmăşanu Monica G.

    2015-01-01

    Full Text Available Introduction. Linear growth failure is caused by multiple factors including parental factors. Objective. The aim of this study was to evaluate parental risk factors for intrauterine growth restriction (IUGR on a population of Romanian newborn infants in a tertiary level maternity facility for a period of 2.5 years. Methods. A retrospective matched case-control study was conducted in the Emergency County Hospital of Cluj-Napoca, a university hospital in North-Western Romania. The sample was selected from 4,790 infants admitted to the Neonatal Ward at 1st Gynecology Clinic between January 2012 and June 2014. Results. The age of mothers was significantly lower in the IUGR group compared to controls (p=0.041. A significantly higher percentage of mothers had hypertension in the IUGR group compared to those in the control group (p0.13. The age of fathers of infants with IUGR proved significantly lower compared to controls (p=0.0278. The analysis of infants’ comorbidities revealed no significant difference between groups for respiratory distress, hyperbilirubinemia, hypocalcaemia, and heart failure (p>0.27. Intracranial hemorrhage, necrotizing enterocolitis and hypoglycemia were significantly higher in the IUGR group compared to controls. The logistic regression identified hypertension as a significant risk factor for IUGR (OR=2.4, 95% CI [1.3-4.5]. Conclusion. Although the age of the mothers and fathers proved significantly lower in the IUGR group compared to controls, only hypertension in the mothers proved significant risk factors for IUGR.

  7. Analysis of Phylogeny and 3D Structure of APOBEC3 Family Proteins%APOBEC3家族蛋白的进化分析和3D结构比对分析

    Institute of Scientific and Technical Information of China (English)

    顾卫国; 吴宏宇; 劳亭嘉; 黄青山

    2008-01-01

    为探寻HIV-1的种间传播路线与范畴进而发现有效的控制物,选取灵长类天然抗病毒因子APOBEC3家族的22种蛋白(以A3G为主)与17例灵长类线粒体(mtDNA)全基因组序列做进化分析研究.结果一致显示除黑猩猩(Pan troglodytes troglodytes,以下简称Pan),大猩猩(Gorilla)以外,猩猩(Pongo)中的某些种也可能是HIV/SIV的贮主或宿主,值得从实践中有目的追溯.不同种属A3G蛋白活性位点与Zn2+结合位点的3D结构比较结果显示人与其他灵长类物种极为相似,预示着A3G 蛋白在结构和功能上是非常保守的.人的APOBEC3 蛋白有 A~H 7种,对它们的活性位点和Zn2+结合位点进行3D比较,hA3B与hA3G的重合度最好,hA3B不会被HIV-1的 Vif 作用与降解,提示进一步探讨hA3B的结构与功能对于控制HIV-1的感染与传播很重要.

  8. HIV-1 Vif与机体内在抗病毒因子APOBEC3G的研究进展

    Institute of Scientific and Technical Information of China (English)

    李岚(综述); 杨怡姝(综述); 李泽琳(审校); 曾毅(审校)

    2005-01-01

    近期研究表明,非允许性细胞中存在的载脂蛋白B mRNA编辑酶催化多肽样蛋白3G(APOBEC3G)是机体内在的抗病毒因子,它在人免疫缺陷病毒(HIV)反转录过程中,使所形成的负链cDNA中的胞嘧啶脱氨,进而降低病毒的感染力.而Vif蛋白可结合APOBEC3G,并激活泛素-蛋白酶体途径,使之降解,拮抗APOBEC3G的抗病毒活性,且二者之间的相互作用还存在种属特异性.Vif与APOBEC3G间的相互作用,为抗HIV药物的研究提供了新靶点.

  9. Lower HIV provirus levels are associated with more APOBEC3G protein in blood resting memory CD4+ T lymphocytes of controllers in vivo.

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    Mariapia De Pasquale

    Full Text Available Immunodeficiency does not progress for prolonged periods in some HLA B57- and/or B27-positive subjects with human immunodeficiency virus type 1 (HIV infection, even in the absence of antiretroviral therapy (ART. These "controllers" have fewer HIV provirus-containing peripheral blood mononuclear cells than "non-controller" subjects, but lymphocytes that harbor latent proviruses were not specifically examined in studies to date. Provirus levels in resting memory cells that can serve as latent reservoirs of HIV in blood were compared here between controllers and ART-suppressed non-controllers. APOBEC3G (A3G, a cellular factor that blocks provirus formation at multiple steps if not antagonized by HIV virion infectivity factor (Vif, was also studied. HLA-linked HIV control was associated with less provirus and more A3G protein in resting CD4+ T central memory (Tcm and effector memory (Tem lymphocytes (provirus: p = 0.01 for Tcm and p = 0.02 for Tem; A3G: p = 0.02 for Tcm and p = 0.02 for Tem. Resting memory T cells with the highest A3G protein levels (>0.5 RLU per unit of actin had the lowest levels of provirus (<1,000 copies of DNA per million cells in vivo (p = 0.03, Fisher's exact test. Using two different experimental approaches, Vif-positive viruses with more A3G were found to have decreased virion infectivity ex vivo. These results raise the hypothesis that HIV control is associated with increased cellular A3G that may be packaged into Vif-positive virions to add that mode of inhibition of provirus formation to previously described adaptive immune mechanisms for HIV control.

  10. Distinct determinants in HIV-1 Vif and human APOBEC3 proteins are required for the suppression of diverse host anti-viral proteins.

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    Wenyan Zhang

    Full Text Available BACKGROUND: APOBEC3G (A3G and related cytidine deaminases of the APOBEC3 family of proteins are potent inhibitors of many retroviruses, including HIV-1. Formation of infectious HIV-1 requires the suppression of multiple cytidine deaminases by Vif. HIV-1 Vif suppresses various APOBEC3 proteins through the common mechanism of recruiting the Cullin5-ElonginB-ElonginC E3 ubiquitin ligase to induce target protein polyubiquitination and proteasome-mediated degradation. The domains in Vif and various APOBEC3 proteins required for APOBEC3 recognition and degradation have not been fully characterized. METHODS AND FINDINGS: In the present study, we have demonstrated that the regions of APOBEC3F (A3F that are required for its HIV-1-mediated binding and degradation are distinct from those reported for A3G. We found that the C-terminal cytidine deaminase domain (C-CDD of A3F alone is sufficient for its interaction with HIV-1 Vif and its Vif-mediated degradation. We also observed that the domains of HIV-1 Vif that are uniquely required for its functional interaction with full-length A3F are also required for the degradation of the C-CDD of A3F; in contrast, those Vif domains that are uniquely required for functional interaction with A3G are not required for the degradation of the C-CDD of A3F. Interestingly, the HIV-1 Vif domains required for the degradation of A3F are also required for the degradation of A3C and A3DE. On the other hand, the Vif domains uniquely required for the degradation of A3G are dispensable for the degradation of cytidine deaminases A3C and A3DE. CONCLUSIONS: Our data suggest that distinct regions of A3F and A3G are targeted by HIV-1 Vif molecules. However, HIV-1 Vif suppresses A3F, A3C, and A3DE through similar recognition determinants, which are conserved among Vif molecules from diverse HIV-1 strains. Mapping these determinants may be useful for the design of novel anti-HIV inhibitors.

  11. Core Binding Factor β Protects HIV, Type 1 Accessory Protein Viral Infectivity Factor from MDM2-mediated Degradation.

    Science.gov (United States)

    Matsui, Yusuke; Shindo, Keisuke; Nagata, Kayoko; Yoshinaga, Noriyoshi; Shirakawa, Kotaro; Kobayashi, Masayuki; Takaori-Kondo, Akifumi

    2016-11-25

    HIV, type 1 overcomes host restriction factor apolipoprotein B mRNA-editing enzyme catalytic polypeptide-like 3 (APOBEC3) proteins by organizing an E3 ubiquitin ligase complex together with viral infectivity factor (Vif) and a host transcription cofactor core binding factor β (CBFβ). CBFβ is essential for Vif to counteract APOBEC3 by enabling the recruitment of cullin 5 to the complex and increasing the steady-state level of Vif protein; however, the mechanisms by which CBFβ up-regulates Vif protein remains unclear. Because we have reported previously that mouse double minute 2 homolog (MDM2) is an E3 ligase for Vif, we hypothesized that CBFβ might protect Vif from MDM2-mediated degradation. Co-immunoprecipitation analyses showed that Vif mutants that do not bind to CBFβ preferentially interact with MDM2 and that overexpression of CBFβ disrupts the interaction between MDM2 and Vif. Knockdown of CBFβ reduced the steady-state level of Vif in MDM2-proficient cells but not in MDM2-null cells. Cycloheximide chase analyses revealed that Vif E88A/W89A, which does not interact with CBFβ, degraded faster than wild-type Vif in MDM2-proficient cells but not in MDM2-null cells, suggesting that Vif stabilization by CBFβ is mainly caused by impairing MDM2-mediated degradation. We identified Vif R93E as a Vif variant that does not bind to MDM2, and the virus with this substitution mutation was more resistant to APOBEC3G than the parental virus. Combinatory substitution of Vif residues required for CBFβ binding and MDM2 binding showed full recovery of Vif steady-state levels, supporting our hypothesis. Our data provide new insights into the mechanism of Vif augmentation by CBFβ.

  12. Construction of eukaryotic vector for porcine APOBEC3F gene and its ex-pression and localization in MARC145 cells%猪 APOBEC3F基因真核表达载体的构建及其在MARC145细胞中的表达定位

    Institute of Scientific and Technical Information of China (English)

    孟春花; 王春玲; 李静心; 李隐侠; 朱前明; 曹少先

    2015-01-01

    载脂蛋白B mRNA编辑酶催化多肽3F( APOBEC3F)属固有免疫系统中的重要成员,对人免疫缺陷病毒( HIV)、乙型肝炎病毒( HBV)等多种病毒的复制具有广泛的抑制作用。为构建APOBEC3F基因的真核表达载体,并检测其在体外培养的MARC145细胞中的表达情况,通过RT⁃PCR从猪脾脏组织扩增APOBEC3F基因,定向克隆到表达增强型绿色荧光蛋白(EGFP)的真核表达载体pEGFP⁃CMV中,构建pEGFP⁃APOBEC3F。 PCR扩增及测序显示,APOBEC3F插入载体位置、方向及序列均正确。 pEGFP⁃APOBEC3F经脂质体介导法转染MARC145细胞,转染后24 h APOBEC3F mRNA的水平升至最高。细胞免疫化学法检测发现APOBEC3F蛋白主要在MARC145细胞质中表达。研究结果为体外研究猪APOBEC3F基因在抗猪蓝耳病中的作用奠定了基础。%Apolipoprotein B mRNA⁃editing enzyme cayalytic polypeptide 3F ( APOBEC3F,A3F) is an important member of innate immune system in mammals, playing vital roles in inhibiting the replication of multiple viruses, such as human immunodeficiency virus (HIV), hepatitis B virus (HBV), etc. Porcine reproductive and respiratory syndrome ( PRRS) , caused by porcine reproductive and respiratory syndrome virus ( PRRSV) , is one of the most economically im⁃portant diseases of swine. No reliable or sustainable cure is available due to some special features of PRRSV. It is one of the effective directions to control PRRS disease by im⁃proving genetic resistance of the host. Our previous study has shown that the polymorphism of A3F gene was associ⁃ated with PRRSV resistance. In this study, A3F gene was amplified by RT⁃PCR and cloned into pEGFP⁃CMV eu⁃karyotic expression vector with enhanced green fluorescence protein ( EGFP ) by using porcine splenic RNA as template and primers based on A3F gene sequences on GenBank. Verified by double enzymes ( BglⅡand SalⅠ) digestion and sequencing, A3F eukarytic

  13. Insights into the dual activity of SIVmac239 Vif against human and African green monkey APOBEC3G.

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    Ritu Gaur

    Full Text Available Human immunodeficiency virus type 1 (HIV-1 Vif is essential for viral evasion of the host antiviral protein APOBEC3G (APO3G. The Vif protein from a distantly related African green monkey (Agm simian immunodeficiency virus (SIVagm is unable to suppress the antiviral activity of human APO3G but is active against Agm APO3G. SIVmac Vif on the other hand, possesses antiviral activity against both human and Agm APO3G. In this study, we were interested in mapping domains in SIVmac Vif that are responsible for its dual activity against human and Agm APO3G. We constructed a series of Vif chimeras by swapping domains in SIVmac Vif with equivalent regions from SIVagm Vif and determined their activity against human and Agm APO3G. We found that replacing any region in SIVmac Vif by corresponding fragments from SIVagm Vif only moderately reduced the activity of the chimeras against Agm APO3G but in all cases resulted in a severe loss of activity against human APO3G. These results suggest that the domains in SIVmac Vif required for targeting human and Agm APO3G are distinct and cannot be defined as linear amino acid motifs but rather appear to depend on the overall structure of full-length SIVmac Vif.

  14. Newly synthesized APOBEC3G is incorporated into HIV virions, inhibited by HIV RNA, and subsequently activated by RNase H.

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    Vanessa B Soros

    2007-02-01

    Full Text Available APOBEC3G (A3G is a potent antiretroviral deoxycytidine deaminase that, when incorporated into HIV virions, hypermutates nascent viral DNA formed during reverse transcription. HIV Vif counters the effect of A3G by depleting intracellular stores of the enzyme, thereby blocking its virion incorporation. Through pulse-chase analyses, we demonstrate that virion A3G is mainly recruited from the cellular pool of newly synthesized enzyme compared to older "mature" A3G already residing in high-molecular-mass RNA-protein complexes. Virion-incorporated A3G forms a large complex with viral genomic RNA that is clearly distinct from cellular HMM A3G complexes, as revealed by both gel filtration and biochemical fractionation. Unexpectedly, the enzymatic activity of virion-incorporated A3G is lost upon its stable association with HIV RNA. The activity of the latent A3G enzyme is ultimately restored during reverse transcription by the action of HIV RNase H. Degradation of the viral genomic RNA by RNase H not only generates the minus-strand DNA substrate targeted by A3G for hypermutation but also removes the inhibitory RNA bound to A3G, thereby enabling its function as a deoxycytidine deaminase. These findings highlight an unexpected interplay between host and virus where initiation of antiviral enzymatic activity is dependent on the action of an essential viral enzyme.

  15. Incomplete APOBEC3G/F Neutralization by HIV-1 Vif Mutants Facilitates the Genetic Evolution from CCR5 to CXCR4 Usage.

    Science.gov (United States)

    Alteri, Claudia; Surdo, Matteo; Bellocchi, Maria Concetta; Saccomandi, Patrizia; Continenza, Fabio; Armenia, Daniele; Parrotta, Lucia; Carioti, Luca; Costa, Giosuè; Fourati, Slim; Di Santo, Fabiola; Scutari, Rossana; Barbaliscia, Silvia; Fedele, Valentina; Carta, Stefania; Balestra, Emanuela; Alcaro, Stefano; Marcelin, Anne Genevieve; Calvez, Vincent; Ceccherini-Silberstein, Francesca; Artese, Anna; Perno, Carlo Federico; Svicher, Valentina

    2015-08-01

    Incomplete APOBEC3G/F neutralization by a defective HIV-1Vif protein can promote genetic diversification by inducing G-to-A mutations in the HIV-1 genome. The HIV-1 Env V3 loop, critical for coreceptor usage, contains several putative APOBEC3G/F target sites. Here, we determined if APOBEC3G/F, in the presence of Vif-defective HIV-1 virus, can induce G-to-A mutations at V3 positions critical to modulation of CXCR4 usage. Peripheral blood mononuclear cells (PBMC) and monocyte-derived macrophages (MDM) from 2 HIV-1-negative donors were infected with CCR5-using 81.A-VifWT virus (i.e., with wild-type [WT] Vif protein), 81.A-VifE45G, or 81.A-VifK22E (known to incompletely/partially neutralize APOBEC3G/F). The rate of G-toA mutations was zero or extremely low in 81.A-VifWT- and 81.A-VifE45G-infected PBMC from both donors. Conversely, G-to-A enrichment was detected in 81.A-VifK22E-infected PBMC (prevalence ranging from 2.18% at 7 days postinfection [dpi] to 3.07% at 21 dpi in donor 1 and from 10.49% at 7 dpi to 8.69% at 21 dpi in donor 2). A similar scenario was found in MDM. G-to-A mutations occurred at 8 V3 positions, resulting in nonsynonymous amino acid substitutions. Of them, G24E and E25K strongly correlated with phenotypically/genotypically defined CXCR4-using viruses (P = 0.04 and 5.5e-7, respectively) and increased the CXCR4 N-terminal binding affinity for V3 (WT, -40.1 kcal/mol; G24E, -510 kcal/mol; E25K, -522 kcal/mol). The analysis of paired V3 and Vif DNA sequences from 84 HIV-1-infected patients showed that the presence of a Vif-defective virus correlated with CXCR4 usage in proviral DNA (P = 0.04). In conclusion, incomplete APOBEC3G/F neutralization by a single Vif amino acid substitution seeds a CXCR4-using proviral reservoir. This can have implications for the success of CCR5 antagonist-based therapy, as well as for the risk of disease progression.

  16. Demonstration of a novel HIV-1 restriction phenotype from a human T cell line.

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    Yanxing Han

    Full Text Available BACKGROUND: Although retroviruses may invade host cells, a productive infection can be established only after the virus counteracts inhibition from different types of host restriction factors. Fv1, APOBEC3G/F, TRIM5alpha, ZAP, and CD317 inhibit the replication of different retroviruses by interfering with viral uncoating, reverse transcription, nuclear import, RNA stability, and release. In humans, although APOBEC3G/3F and CD317 block HIV-1 replication, their antiviral activities are neutralized by viral proteins Vif and Vpu. So far, no human gene has been found to effectively block wild type HIV-1 replication under natural condition. Thus, identification of such a gene product would be of great medical importance for the development of HIV therapies. METHOD AND FINDINGS: In this study, we discovered a new type of host restriction against the wild type HIV-1 from a CD4/CXCR4 double-positive human T cell line. We identified a CEM-derived cell line (CEM.NKR that is highly resistant to productive HIV-1 infection. Viral production was reduced by at least 1000-fold when compared to the other permissive human T cell lines such as H9, A3.01, and CEM-T4. Importantly, this resistance was evident at extremely high multiplicity of infection. Further analyses demonstrated that HIV-1 could finish the first round of replication in CEM.NKR cells, but the released virions were poorly infectious. These virions could enter the target cells, but failed to initiate reverse transcription. Notably, this restriction phenotype was also present in CEM.NKR and 293T heterokaryons. CONCLUSIONS: These results clearly indicate that CEM.NKR cells express a HIV inhibitory gene(s. Further characterization of this novel gene product(s will reveal a new antiretroviral mechanism that directly inactivates wild type HIV-1.

  17. An ancient history of gene duplications, fusions and losses in the evolution of APOBEC3 mutators in mammals

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    Münk Carsten

    2012-05-01

    Full Text Available Abstract Background The APOBEC3 (A3 genes play a key role in innate antiviral defense in mammals by introducing directed mutations in the DNA. The human genome encodes for seven A3 genes, with multiple splice alternatives. Different A3 proteins display different substrate specificity, but the very basic question on how discerning self from non-self still remains unresolved. Further, the expression of A3 activity/ies shapes the way both viral and host genomes evolve. Results We present here a detailed temporal analysis of the origin and expansion of the A3 repertoire in mammals. Our data support an evolutionary scenario where the genome of the mammalian ancestor encoded for at least one ancestral A3 gene, and where the genome of the ancestor of placental mammals (and possibly of the ancestor of all mammals already encoded for an A3Z1-A3Z2-A3Z3 arrangement. Duplication events of the A3 genes have occurred independently in different lineages: humans, cats and horses. In all of them, gene duplication has resulted in changes in enzyme activity and/or substrate specificity, in a paradigmatic example of convergent adaptive evolution at the genomic level. Finally, our results show that evolutionary rates for the three A3Z1, A3Z2 and A3Z3 motifs have significantly decreased in the last 100 Mya. The analysis constitutes a textbook example of the evolution of a gene locus by duplication and sub/neofunctionalization in the context of virus-host arms race. Conclusions Our results provide a time framework for identifying ancestral and derived genomic arrangements in the APOBEC loci, and to date the expansion of this gene family for different lineages through time, as a response to changes in viral/retroviral/retrotransposon pressure.

  18. The resistance of human APOBEC3H to HIV-1 NL4-3 molecular clone is determined by a single amino acid in Vif.

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    Ooms, Marcel; Letko, Michael; Binka, Mawuena; Simon, Viviana

    2013-01-01

    Some human APOBEC3 cytidine deaminases have antiviral activity against HIV-1 and other retroviruses. The single deaminase domain APOBEC3H (A3H) enzyme is highly polymorphic and multiple A3H haplotypes have been identified. A3H haplotype II (A3H-hapII) possesses the strongest activity against HIV-1. There remains, however, uncertainty regarding the extent to which A3H-hapII is sensitive to HIV-1 Vif mediated degradation. We tested, therefore, the two different reference Vif proteins widely used in previous studies. We show that A3H-hapII is resistant to NL4-3 Vif while it is efficiently degraded by LAI Vif. Co-immunoprecipitation assays demonstrate that LAI Vif, but not NL4-3 Vif associates with A3H-hapII. Chimeras between NL4-3 and LAI Vif identify the amino acid responsible for the differential degradation activity: A histidine at position 48 in Vif confers activity against A3H-hapII, while an asparagine abolishes its anti-A3H activity. Furthermore, the amino acid identity at position 48 only affects the degradation of A3H-hapII, whereas recognition of and activity against human A3D, A3F and A3G are only minimally affected. NL4-3 encoding 48H replicates better than NL4-3 WT (48N) in T cell-lines stably expressing A3H hapII, whereas there is no fitness difference in the absence of APOBEC3. These studies provide an explanation for the conflicting reports regarding A3H resistance to Vif mediated degradation.

  19. Risk Factors for Restricting Back Pain in Older Persons

    Science.gov (United States)

    Makris, Una E.; Fraenkel, Liana; Han, Ling; Leo-Summers, Linda; Gill, Thomas M.

    2013-01-01

    Objectives To identify risk factors for back pain leading to restricted activity (restricting back pain) in older persons. Design Prospective cohort study. Setting Greater New Haven, Connecticut. Participants 731 men and women aged 70 years or older, who were community-living and non-disabled in essential activities of daily living at baseline. Measurements Candidate risk factors were ascertained every 18 months for 108 months during comprehensive home-based assessments. Restricting back pain was assessed during monthly telephone interviews for up to 126 months. Incident episodes of: (1) short-term (one episode lasting one month) restricting back pain; and (2) persistent (one episode lasting two or more months) or recurrent (two or more episodes of any duration) restricting back pain were determined during each 18-month interval. The associations between the candidate risk factors and short-term and persistent/recurrent restricting back pain, respectively, were evaluated using a multivariable Cox model. Results The cumulative incidence was 21.3% (95% confidence interval (CI) 19.6%, 23.1%) for short-term restricting back pain and 20.6% (CI 18.6%, 22.9%) for persistent/recurrent restricting back pain over a median follow-up of 109 months. In a recurrent event multivariable analysis, female sex (HR 1.30; 1.07, 1.58), weak grip strength (HR 1.24; 1.01,1.52), and hip weakness (HR 1.19; 1.07,1.32) were independently associated with an increased likelihood of having short-term restricting back pain, while female sex (HR 1.48; CI 1.13,1.94), depressive symptoms (HR 1.57; 1.23, 2.00), 2 or more chronic conditions (HR 1.38; 1.08, 1.77), and arthritis (HR1.66; 1.31, 2.09) were independently associated with persistent/recurrent restricting back pain. Conclusion In this prospective study, several factors were independently associated with restricting back pain, including some that may be modifiable and therefore potential targets for interventions to reduce this common and

  20. APOBEC3G抗HIV-1的分子机制及Vif基因对其拮抗作用研究进展%Research and Development of Molecular Mechanism of APOBEC3G's Anti HIV-1 Effects and Vif's Antagonism to Them

    Institute of Scientific and Technical Information of China (English)

    屠燕捷

    2012-01-01

    The high pathogenic rate and high mortality rates of AIDS have caught more attention for recent three decades. The expectation is focused on HIV/AIDS prevention and great breakthrough in Traditional Chinese Medicine (TCM) research. This article introduced research and development of molecular mechanism of APOBEC3G's anti HIV-1 effects and the gene vif's antagonism to them. The goal is to discuss the significance of HIV gene therapy and the potential research direction of TCM for HIV treatment.%近30年,艾滋病的高致病率和高死亡率一直被医学界高度关注,期望通过中医药研究在艾滋病防治上寻求突破,从而引发了中医药研究与分子生物学研究交叉与结合.由于近10年HIV的分子生物学研究文献,发现HIV的辅助蛋白vif和APOBEC3G为当前艾滋病致病机制研究的热点.本文对HIV的辅助蛋白vif的生物学特性、APOBEC3G抗HIV-1的分子机制及vif与APOBEC3G相互作用的新近研究成果进行整理分析,探讨基于此进行HIV基因治疗的意义以及中医药治疗HIV可能的研究方向.

  1. Restricting factors of the development of SEA in China

    Institute of Scientific and Technical Information of China (English)

    Wang Xianghua; Zhu Xiaodong; LiYangfan; Chen Shanshan

    2006-01-01

    "Environmental Impact Assessment Law of P. R. China" was promulgated on Oct. 28th, 2002 and has been put into effect on Sep 1st, 2003. This paper puts forward some important factors which restrict the development of Strategic Environmental Assessment according to the preliminary practices of SEA in China. These restricting factors are: (1) potential resistance from some departments; (2) poor cooperation between different departments; (3) limited availability of information resources; (4) lack of well-developed SEA methods; (5) difficulties in public participation. The primary thought to solve these problems were proposed at policy and technique level.

  2. Differential Contributions of Ubiquitin-Modified APOBEC3G Lysine Residues to HIV-1 Vif-Induced Degradation.

    Science.gov (United States)

    Turner, Tiffany; Shao, Qiujia; Wang, Weiran; Wang, Yudi; Wang, Chenliang; Kinlock, Ballington; Liu, Bindong

    2016-08-28

    Apolipoprotein B mRNA-editing enzyme-catalytic polypeptide-like 3G (A3G) is a host restriction factor that impedes HIV-1 replication. Viral integrity is salvaged by HIV-1 virion infectivity factor (Vif), which mediates A3G polyubiquitination and subsequent cellular depletion. Previous studies have implied that A3G polyubiquitination is essential for Vif-induced degradation. However, the contribution of polyubiquitination to the rate of A3G degradation remains unclear. Here, we show that A3G polyubiquitination is essential for degradation. Inhibition of ubiquitin-activating enzyme E1 by PYR-41 or blocking the formation of ubiquitin chains by over-expressing the lysine to arginine mutation of ubiquitin K48 (K48R) inhibited A3G degradation. Our A3G mutagenesis study showed that lysine residues 297, 301, 303, and 334 were not sufficient to render lysine-free A3G sensitive to Vif-mediated degradation. Our data also confirm that Vif could induce ubiquitin chain formation on lysine residues interspersed throughout A3G. Notably, A3G degradation relied on the lysine residues involved in polyubiquitination. Although A3G and the A3G C-terminal mutant interacted with Vif and were modified by ubiquitin chains, the latter remained more resistant to Vif-induced degradation. Furthermore, the A3G C-terminal mutant, but not the N-terminal mutant, maintained potent antiviral activity in the presence of Vif. Taken together, our results suggest that the location of A3G ubiquitin modification is a determinant for Vif-mediated degradation, implying that in addition to polyubiquitination, other factors may play a key role in the rate of A3G degradation.

  3. APOBEC3A is implicated in a novel class of G-to-A mRNA editing in WT1 transcripts.

    Directory of Open Access Journals (Sweden)

    Ahmadreza Niavarani

    Full Text Available Classic deamination mRNA changes, including cytidine to uridine (C-to-U and adenosine to inosine (A-to-I, are important exceptions to the central dogma and lead to significant alterations in gene transcripts and products. Although there are a few reports of non-classic mRNA alterations, as yet there is no molecular explanation for these alternative changes. Wilms Tumor 1 (WT1 mutations and variants are implicated in several diseases, including Wilms tumor and acute myeloid leukemia (AML. We observed two alternative G-to-A changes, namely c.1303G>A and c.1586G>A in cDNA clones and found them to be recurrent in a series of 21 umbilical cord blood mononuclear cell (CBMC samples studied. Two less conserved U-to-C changes were also observed. These alternative changes were found to be significantly higher in non-progenitor as compared to progenitor CBMCs, while they were found to be absent in a series of AML samples studied, indicating they are targeted, cell type-specific mRNA editing modifications. Since APOBEC/ADAR family members are implicated in RNA/DNA editing, we screened them by RNA-interference (RNAi for WT1-mRNA changes and observed near complete reversal of WT1 c.1303G>A alteration upon APOBEC3A (A3A knockdown. The role of A3A in mediating this change was confirmed by A3A overexpression in Fujioka cells, which led to a significant increase in WT1 c.1303G>A mRNA editing. Non-progenitor CBMCs showed correspondingly higher levels of A3A-mRNA and protein as compared to the progenitor ones. To our knowledge, this is the first report of mRNA modifying activity for an APOBEC3 protein and implicates A3A in a novel G-to-A form of editing. These findings open the way to further investigations into the mechanisms of other potential mRNA changes, which will help to redefine the RNA editing paradigm in both health and disease.

  4. Interaction of human immunodeficiency virus type 1 Vif with APOBEC3G is not dependent on serine/threonine phosphorylation status.

    Science.gov (United States)

    Kopietz, Ferdinand; Jaguva Vasudevan, Ananda Ayyappan; Krämer, Melanie; Muckenfuss, Heide; Sanzenbacher, Ralf; Cichutek, Klaus; Flory, Egbert; Münk, Carsten

    2012-11-01

    The human immunodeficiency virus type 1 accessory protein Vif is important for viral infectivity because it counteracts the antiviral protein APOBEC3G (A3G). ³²P metabolic labelling of stimulated cells revealed in vivo phosphorylation of the control protein, whereas no serine/threonine phosphorylation was detected for Vif or the A3G protein. These data were confirmed by in vitro kinase assays using active recombinant kinase. Mitogen-activated protein kinase/extracellular signal-regulated kinase 2 efficiently phosphorylated its target ELK, but failed to phosphorylate Vif. Putative serine/threonine phosphorylation point mutations in Vif (T96, S144, S165, T188) using single-round infection assays demonstrated that these mutations did not alter Vif activity, with the exception of Vif.T96E. Interestingly, T96E and not T96A was functionally impaired, indicating that this residue is critical for Vif-A3G physical interaction and activity. Our data suggest that Vif and A3G are not serine/threonine phosphorylated in human cells and phosphorylation is not linked to their functional activities.

  5. Molecular modeling of human APOBEC3G to predict the binding modes of the inhibitor compounds IMB26 and IMB35

    Directory of Open Access Journals (Sweden)

    Zhixin Zhang

    2013-07-01

    Full Text Available APOBEC3G(A3G is a host cytidine deaminase that incorporates into HIV-1 virions and efficiently inhibits viral replication. The virally encoded protein Vif binds to A3G and induces its degradation, thereby counteracting the antiviral activity of A3G. Vif-mediated A3G degradation clearly represents a potential target for anti-HIV drug development. Currently, there is an urgent need for understanding the three dimensional structure of full-length A3G. In this work, we use a homology modeling approach to propose a structure for A3G based on the crystal structure of APOBEC2 (APO2 and the catalytic domain structure of A3G. Two compounds, IMB26 and IMB35, which have been shown to bind to A3G and block degradation by Vif, were docked into the A3G model and the binding modes were generated for further analysis. The results may be used to design or optimize molecules targeting Vif–A3G interaction, and lead to the development of novel anti-HIV drugs.

  6. APOBEC3G-mediated G-to-A hypermutation of the HIV-1 genome: the missing link in antiviral molecular mechanisms

    Directory of Open Access Journals (Sweden)

    Ayaka Okada

    2016-12-01

    Full Text Available APOBEC3G (A3G is a member of the cellular polynucleotide cytidine deaminases, which catalyze the deamination of cytosine (dC to uracil (dU in single-stranded DNA. These enzymes potently inhibit the replication of a variety of retroviruses and retrotransposons, including HIV-1. A3G is incorporated into vif-deficient HIV-1 virions and targets viral reverse transcripts, particularly minus-stranded DNA products, in newly infected cells. It is well established that the enzymatic activity of A3G is closely correlated with the potential to greatly inhibit HIV-1 replication in the absence of Vif. However, the details of the underlying molecular mechanisms are not fully understood. One potential mechanism of A3G antiviral activity is that the A3G-dependent deamination may trigger degradation of the dU-containing reverse transcripts by cellular uracil DNA glycosylases (UDGs. More recently, another mechanism has been suggested, in which the virion-incorporated A3G generates lethal levels of the G-to-A hypermutation in the viral DNA genome, thus potentially driving the viruses into error catastrophe mode. In this mini review article, we summarize the deaminase-dependent and deaminase-independent molecular mechanisms of A3G and discuss how A3G-mediated deamination is linked to antiviral mechanisms.

  7. Cacao in México: Restrictive factors and productivity levels

    Directory of Open Access Journals (Sweden)

    Julio Díaz-José

    2014-12-01

    Full Text Available Cacao (Theobroma cacao L. represents one of the most important agricultural crops of the humid Mexican tropics. In the last 10 yr, approximately 23.000 t of this grain were no longer produced per cycle. The objective of this study was to identify characteristics and factors that restrict production in the states of Tabasco and Chiapas. A survey was applied to obtain information about 184 producers and their plantations by two-stage sampling. Descriptive statistics were calculated and multilevel models were adjusted to analyze the information. Results show that there are differences (P < 0.05 in cacao yield between municipalities (380 kg ha-1 + u,o j is the estimated residual for each municipality. Crop productivity levels are higher in the state of Tabasco than in Chiapas (644 and 344 kg ha-1, respectively. Incidence of frosty pod rot of cacoa, also known as moniliasis, induced by Moniliophthora roreri [(Cif H.C. Evans, Stalpers, Samson & Benny 1978] is significantly greater (P < 0.05 in the state of Chiapas (60% than in Tabasco (48%.Producers who carry out more crop management practices increase yields and decrease the pathogen's impact on their plantations. Results suggest the need to apply differentiated public policies to promote production within each region or municipality.

  8. Restricting Factors at Modification of Parameters of Associative Engineering Objects

    Science.gov (United States)

    Horváth, László

    Advancements in product development have reached full integration of engineering activities and processes in product lifecycle management (PLM) systems. PLM systems are based on high-level modeling, simulation and data management. Despite significant development of modeling in PLM systems, a strong demand was recognized for improved decision assistance in product development. Decision assistance can be improved by application of methods from the area of computer intelligence. In order for a product development company to stay competitive, it is important for its modeling system to be relied on local even personal knowledge. The authors analyzed current PLM systems for shortcomings and possibilities for extended intelligence at decision-making during product development. They propose methods in order to increase suitability of current modeling systems to accommodate knowledge based IT at definition of sets of parameters of modeled objects and in the management of frequent changes of modeled objects. In the center of the proposed methodology, constrained parameters act as restricting factors at definition and modification of parameters of associative engineering objects. Paper starts with an outlook to modeling in current engineering systems and preliminary results by the authors. Following this, groups of essential information as handled by he proposed modeling are summarized and procedures for processing of that groups of information are detailed. Next, management of chains of changes along chains of associa-tive product objects and a new style of decision assistance in modeling systems are explained. Changes are created or verified by behavior analysis. Finally, behavior analysis, human intent combination, product data view creation, and change management are discussed as the proposed integrated and coordinated methodology for enhanced support of decision-making in product development.

  9. A Study of Evaluation System of Restricting Factors in Training Students' Qualities

    Institute of Scientific and Technical Information of China (English)

    MA Xiao-yan

    2002-01-01

    This paper studies evaluation system of restricting factors in training students' qualities by modern mathematical method of analysis hierarchy process and principal factor analysis, and to build up a mathematical model of evaluation system.

  10. The artiodactyl APOBEC3 innate immune repertoire shows evidence for a multi-functional domain organization that existed in the ancestor of placental mammals

    Directory of Open Access Journals (Sweden)

    Andrésdóttir Valgerdur

    2008-11-01

    Full Text Available Abstract Background APOBEC3 (A3 proteins deaminate DNA cytosines and block the replication of retroviruses and retrotransposons. Each A3 gene encodes a protein with one or two conserved zinc-coordinating motifs (Z1, Z2 or Z3. The presence of one A3 gene in mice (Z2–Z3 and seven in humans, A3A-H (Z1a, Z2a-Z1b, Z2b, Z2c-Z2d, Z2e-Z2f, Z2g-Z1c, Z3, suggests extraordinary evolutionary flexibility. To gain insights into the mechanism and timing of A3 gene expansion and into the functional modularity of these genes, we analyzed the genomic sequences, expressed cDNAs and activities of the full A3 repertoire of three artiodactyl lineages: sheep, cattle and pigs. Results Sheep and cattle have three A3 genes, A3Z1, A3Z2 and A3Z3, whereas pigs only have two, A3Z2 and A3Z3. A comparison between domestic and wild pigs indicated that A3Z1 was deleted in the pig lineage. In all three species, read-through transcription and alternative splicing also produced a catalytically active double domain A3Z2-Z3 protein that had a distinct cytoplasmic localization. Thus, the three A3 genes of sheep and cattle encode four conserved and active proteins. These data, together with phylogenetic analyses, indicated that a similar, functionally modular A3 repertoire existed in the common ancestor of artiodactyls and primates (i.e., the ancestor of placental mammals. This mammalian ancestor therefore possessed the minimal A3 gene set, Z1-Z2-Z3, required to evolve through a remarkable series of eight recombination events into the present day eleven Z domain human repertoire. Conclusion The dynamic recombination-filled history of the mammalian A3 genes is consistent with the modular nature of the locus and a model in which most of these events (especially the expansions were selected by ancient pathogenic retrovirus infections.

  11. Factors underlying restricted crossover localization in barley meiosis.

    Science.gov (United States)

    Higgins, James D; Osman, Kim; Jones, Gareth H; Franklin, F Chris H

    2014-01-01

    Meiotic recombination results in the formation of cytological structures known as chiasmata at the sites of genetic crossovers (COs). The formation of at least one chiasma/CO between homologous chromosome pairs is essential for accurate chromosome segregation at the first meiotic division as well as for generating genetic variation. Although DNA double-strand breaks, which initiate recombination, are widely distributed along the chromosomes, this is not necessarily reflected in the chiasma distribution. In many species there is a tendency for chiasmata to be distributed in favored regions along the chromosomes, whereas in others, such as barley and some other grasses, chiasma localization is extremely pronounced. Localization of chiasma to the distal regions of barley chromosomes restricts the genetic variation available to breeders. Studies reviewed herein are beginning to provide an explanation for chiasma localization in barley. Moreover, they suggest a potential route to manipulating chiasma distribution that could be of value to plant breeders.

  12. Computation of the pseudoskin factor for a restricted-entry well

    Energy Technology Data Exchange (ETDEWEB)

    Ding, W. (Joshi Technologies International Inc., Tulsa, OK (United States)); Reynolds, A.C. Jr. (Univ. of Tulsa, OK (United States))

    1994-03-01

    Wells frequently are completed over a fraction of the oil zone to delay water and gas coning. This type of completion is called a restricted-entry or partially penetrating well. When analyzing well-test data from a restricted-entry well, semilog analysis of pseudoradial flow data yields an estimate of the total skin factor, which is a linear combination of the mechanical skin factor and the pseudoskin factor caused by restricted entry. This work presented two new equations for computing the pseudoskin factor from a restricted-entry well completed in a multilayer reservoir. These equations represent generalization of formulas presented by Papatzacos and Vrbik for single-layer homogeneous reservoirs. For ranges of reservoir and well parameters ordinarily encountered, the new equations provide results approximately equal to those obtained from the Yeh-Reynolds calculation procedure, but are easier to use than this equation.

  13. some notes on discount factor restrictions for dynamic optimization problems

    OpenAIRE

    Gerhard Sorger

    2008-01-01

    We consider dynamic optimization problems on one-dimensional state spaces. Un- der standard smoothness and convexity assumptions, the optimal solutions are characterized by an optimal policy function h mapping the state space into itself. There exists an extensive literature on the relation between the size of the discount factor of the dynamic optimization problem on the one hand and the properties of the dynamical system xt+1 = h(xt) on the other hand. The purpose of this paper is to survey...

  14. Differential expression of HIV-1 interfering factors in monocyte-derived macrophages stimulated with polarizing cytokines or interferons

    Science.gov (United States)

    Jiménez, Viviana Cobos; Booiman, Thijs; de Taeye, Steven W.; van Dort, Karel A.; Rits, Maarten A. N.; Hamann, Jörg; Kootstra, Neeltje A.

    2012-10-01

    HIV-1 replication in macrophages can be regulated by cytokines and infection is restricted in macrophages activated by type I interferons and polarizing cytokines. Here, we observed that the expression levels of the cellular factors Trim5α, CypA, APOBEC3G, SAMHD-1, Trim22, tetherin and TREX-1, and the anti-HIV miRNAs miR-28, miR-150, miR-223 and miR-382 was upregulated by IFN-α and IFN-β in macrophages, which may account for the inhibiting effect on viral replication and the antiviral state of these cells. Expression of these factors was also increased by IFN-γ +/- TNF-α, albeit to a lesser extent; yet, HIV-1 replication in these cells was not restricted at the level of proviral synthesis, indicating that these cellular factors only partially contribute to the observed restriction. IL-4, IL-10 or IL-32 polarization did not affect the expression of cellular factors and miRNAs, suggesting only a limited role for these cellular factors in restricting HIV-1 replication in macrophages.

  15. Removing phase-space restrictions in factorized cross sections

    CERN Document Server

    Feige, Ilya; Yan, Kai

    2015-01-01

    Factorization in gauge theories holds at the amplitude or amplitude-squared level for states of given soft or collinear momenta. When performing phase-space integrals over such states, one would generally like to avoid putting in explicit cuts to separate soft from collinear momenta. Removing these cuts induces an overcounting of the soft-collinear region and adds new infrared-ultraviolet divergences in the collinear region. In this paper, we first present a regulator-independent subtraction algorithm for removing soft-collinear overlap at the amplitude level which may be useful in pertubative QCD. We then discuss how both the soft-collinear and infrared-ultraviolet overlap can be undone for certain observables in a way which respects factorization. Our discussion clarifies some of the subtleties in phase-space subtractions and includes a proof of the infrared finiteness of a suitably subtracted jet function. These results complete the connection between factorized QCD and Soft-Collinear Effective Theory.

  16. 载脂蛋白B mRNA编辑酶催化多肽样3G在不同慢性乙型肝炎患者中的表达及其细胞内定位%Expression and subcellular localization of APOBEC3G in peripheral blood mononuclear cells and liver tissues of chronic HBV patients

    Institute of Scientific and Technical Information of China (English)

    陈辉; 王鲁文; 褚小刚; 严少南; 龚作炯

    2010-01-01

    Objective To study the expression level and intracellular localization of APOBEC3G in peripheral blood mononuclear cells (PBMCs) andliver tissues of chronic HBV patients. Methods The expression level and intracellular localization of APOBEC3G in PBMCs and liver tissues were detected using the western blot and confocal laser scanning microscope (CLSM). Results Western-blot showed that the expression level of APOBEC3G in PBMCs of healthy controls was very low. The relative expression levels of APOBEC3G in PBMC of patients with chronic hepatitis B, chronic severe hepatitis, liver cirrhosis, or liver cancer were 4.12±0.21, 4.07± 0.28, 4.16± 0.36 or 4.21±0.39 respectively, which were higher than that in the healthy controls. However, there was no significant difference in APOBEC3G expression among differ-ent chronic HBV patients (q = 0.931, 0.744, 1.675, 1.675, 2.606 or 0.931, respectively, all P values >0.05). In addition, there was no significant difference on APOBEC3G in liver tissues between chronic hepatitis B patients and bepatocellular carcinoma patients (4.40 ± 0.34 vs 4.34 ± 0.43, q = 0.588, P > 0.05). CLSM indicated that the localization of APOBEC3G protein was in cytoplasm of PBMCs and hepatoeytes. Conclu-sion APOBEC3G is upregulated in the PBMCs of chronic hepatitis B patients.%目的 观察载脂蛋白B mRNA编辑酶催化多肽样3G(APOBEC3G)在不同慢性乙型肝炎病毒(HBV)感染类型患者的外周血单个核细胞(PBMC)及肝组织中的表达水平及其细胞内定位.方法 用Western blot及激光扫描共聚焦显微镜,以健康人为对照,检测不同慢性HBV感染类型患者(慢性乙型肝炎、慢性乙型重型肝炎、肝炎肝硬化、HBV相关性肝癌)的PBMC及肝组织中APOBEC3G的表达状况及其亚细胞定位.多组比较采用方差分析,两两比较采用q检验.结果 Western blot结果显示,健康人PBMC中APOBEC3G表达水平极低,慢性乙型肝炎、慢性乙型重型肝炎、肝炎肝硬化和HBV相关性肝癌患者PBMC中APOBEC

  17. Splicing factor 1 modulates dietary restriction and TORC1 pathway longevity in C. elegans

    DEFF Research Database (Denmark)

    Heintz, Caroline; Doktor, Thomas K; Lanjuin, Anne;

    2017-01-01

    via splicing factor 1 (SFA-1; the C. elegans homologue of SF1, also known as branchpoint binding protein, BBP). We show that SFA-1 is specifically required for lifespan extension by dietary restriction and by modulation of the TORC1 pathway components AMPK, RAGA-1 and RSKS-1/S6 kinase. We also...... homeostasis is a biomarker and predictor of life expectancy in Caenorhabditis elegans. Using transcriptomics and in-depth splicing analysis in young and old animals fed ad libitum or subjected to dietary restriction, we find defects in global pre-mRNA splicing with age that are reduced by dietary restriction...

  18. CBF-β required for SIVagm Vif-mediated A3G degradation%CBF-β辅助SIVagm Vif蛋白诱导限制因子APOBEC3G的降解

    Institute of Scientific and Technical Information of China (English)

    朱丹彤; 艾有为; 林跃智; 马建章; 王晓钧; 侯志军; 张明海

    2015-01-01

    APOBEC3蛋白家族是一类重要的慢病毒复制的免疫限制因子.慢病毒编码的附属蛋白Vif可以与Cullin5-Elongin B/Elongin C形成E3泛素化连接酶复合物使APOBEC3G (A3G)聚泛素化和降解,从而抑制A3G对病毒的限制.CBF-β为RUNX家族转录辅助因子,可以调节Vif介导的A3G降解作用.为探索CBF-β对非洲绿猴免疫缺陷病毒Vif蛋白(SIVagm Vif)的调节机制以及对A3G降解的影响,本研究通过生化及病毒学方法对SIVagm和HIV-1编码的Vif蛋白与CBF-β作用进行了对比性研究.结果显示,SIVagm编码的Vif对A3G的降解同样需要CBF-β的辅助.当Vif (HIV-1/SIVagm)编码的第38位色氨酸突变成丝氨酸后,CBF-β辅助Vif调节A3G降解的功能显著降低.由此表明,第38位色氨酸对于不同慢病毒编码的Vif与CBF-β的相互作用具有重要作用.由此推测,CBF-β辅助Vif介导的降解A3G的作用在灵长类慢病毒中具有保守性.

  19. Restrictive Factors of Vocational Education Development in Cultivation of Rural Practical Skilled Personnel and Countermeasures

    OpenAIRE

    2014-01-01

    Kunming City is accelerating the process of agricultural modernization, industrialization, informationization and ecological development. In this process, it needs speeding up building new high level and advanced rural practical skilled personnel team suitable for development demand. By empirical analysis method, this paper discussed the factors restricting vocational education in cultivation of rural practical skilled personnel. Then, it came up with countermeasures in cultivation objective ...

  20. Inter-organizational relationships: promoters and restrictive factors in the formation of cooperation network

    Directory of Open Access Journals (Sweden)

    Marcos Antonio Gaspar

    2014-04-01

    Full Text Available The present paper had as aim to identify factors of inter-organizational relationships which promotes and restricts the formation of companies’ cooperation network, from two levels of analysis (organizational and inter-organizational. To achieve this goal, it was developed a descriptive-qualitative study, with prospecting for primary and secondary data on a cooperation network. The universe was composed by 41 participating companies associated to the analyzed network. The sampling procedure was for researcher’s accessibility and convenience. As a result, it was identified that the network is guided by goals of cooperation among the participating companies, in addition to representing the sector and provide services in the interests of the associates. The main factors influencing the formation of the network were: business center, marketing and training; but only training has been achieved satisfactorily. The business center and marketing factors have not yet been fully developed, being both identified as restrictive factors.

  1. The function and evolution of the restriction factor viperin in primates was not driven by lentiviruses

    Directory of Open Access Journals (Sweden)

    Lim Efrem S

    2012-06-01

    Full Text Available Abstract Background Viperin, also known as RSAD2, is an interferon-inducible protein that potently restricts a broad range of different viruses such as influenza, hepatitis C virus, human cytomegalovirus and West Nile virus. Viperin is thought to affect virus budding by modification of the lipid environment within the cell. Since HIV-1 and other retroviruses depend on lipid domains of the host cell for budding and infectivity, we investigated the possibility that Viperin also restricts human immunodeficiency virus and other retroviruses. Results Like other host restriction factors that have a broad antiviral range, we find that viperin has also been evolving under positive selection in primates. The pattern of positive selection is indicative of Viperin's escape from multiple viral antagonists over the course of primate evolution. Furthermore, we find that Viperin is interferon-induced in HIV primary target cells. We show that exogenous expression of Viperin restricts the LAI strain of HIV-1 at the stage of virus release from the cell. Nonetheless, the effect of Viperin restriction is highly strain-specific and does not affect most HIV-1 strains or other retroviruses tested. Moreover, knockdown of endogenous Viperin in a lymphocytic cell line did not significantly affect the spreading infection of HIV-1. Conclusion Despite positive selection having acted on Viperin throughout primate evolution, our findings indicate that Viperin is not a major restriction factor against HIV-1 and other retroviruses. Therefore, other viral lineages are likely responsible for the evolutionary signatures of positive selection in viperin among primates.

  2. Demand Forecasting at Low Aggregation Levels using Factored Conditional Restricted Boltzmann Machine

    DEFF Research Database (Denmark)

    Mocanu, Elena; Nguyen, Phuong H.; Gibescu, Madeleine

    2016-01-01

    The electrical demand forecasting problem can be regarded as a nonlinear time series prediction problem depending on many complex factors since it is required at various aggregation levels and at high temporal resolution. To solve this challenging problem, various time series and machine learning...... developed deep learning model for time series prediction, namely Factored Conditional Restricted Boltzmann Machine (FCRBM), and extend it for electrical demand forecasting. The assessment is made on the EcoGrid dataset, originating from the Bornholm island experiment in Denmark, consisting of aggregated...

  3. Dual roles of lineage restricted transcription factors: the case of MITF in melanocytes.

    Science.gov (United States)

    Levy, Carmit; Fisher, David E

    2011-01-01

    Microphthalmia-associated Transcription Factor, MITF, is a master regulator of melanocyte development, differentiation, migration, and survival.(1) A broad collection of studies have indicated that MITF directly regulates the transcription of genes involved in pigmentation, which are selective to the melanocyte lineage. In addition, MITF controls expression of genes which are expressed in multiple cell lineages, and may also play differential roles in activating vs. maintaining gene expression patterns. In this Point of View article, we discuss lineage restricted transcription factor activation of both tissue-specific and ubiquitously expressed genes using melanocytes and MITF as a model system that may eventually provide insights into such processes in multiple cell lineages.

  4. Quantification and control of restrictive ecological factors in acidogenic de-sulfate bioreactor

    Institute of Scientific and Technical Information of China (English)

    王爱杰; 任南琪

    2002-01-01

    As an artificial microbial ecosystem, acidogenic de-sulfate bioreactor has high efficiency of sulfate removal. The restrictive ecological factors, including causing ecological factors, such as COD/SO42- ratio and sulfate loading rate (Ns), and following ecological factors, such as pH value, oxidation reduction potential (ORP) and alkalinity (ALK) have significant effect on the ability and stability of acidogenic de-sulfate bio-reactor. Continuous flow and batch test were carried out to investigate the quantification and control of COD/SO42- ratio, Ns, pH value, ORP and ALK in acidogenic de-sulfate bioreactor supplied with molasses wastewater as sole organic carbon source and sodium sulfate as electron donor. It was demonstrated that In order to maintain high sulfate removal rate (SRR) of 80% to 90%, the restrictive factors should meet all the requirement as follows: kCOD/ SO42- ratio≥2.0, Ns≤7.5 kg (m3·d)-1,pH=5.7~6.2,ORP=-320~-420 mV and ALK=1 500~2 000 mg/L.

  5. Factors that restrict the intestinal cell permeation of cyclic prodrugs of an opioid peptide (DADLE)

    DEFF Research Database (Denmark)

    Ouyang, Hui; Chen, Weiqing; Andersen, Thomas E;

    2009-01-01

    inactive or substantially less active than PSC-833 in increasing the P(B) values of these prodrugs. These data suggest that, while P-gp plays a role, other factors (e.g., substrate activity for other efflux transporters and/or for metabolic enzymes) may contribute to restricting the permeation of AOA......The objective of this study was to elucidate the role of P-glycoprotein (P-gp) in restricting the intestinal mucosal permeation of cyclic prodrugs (AOA-DADLE, CA-DADLE, and OMCA-DADLE) of the opioid peptide DADLE (H-Tyr-D-Ala-Gly-Phe-D-Leu-OH). In the Caco-2 cell model, the high P......(app,BL-to-AP)/P(app,AP-to-BL) ratios of AOA-DADLE, CA-DADLE, and OMCA-DADLE (71-117) were significantly decreased by including known P-gp inhibitors, GF-12098, cyclosporine (CyA), or PSC-833, in the incubation media, suggesting that P-gp is restricting the AP-to-BL permeation of these cyclic prodrugs. In the in situ perfused rat...

  6. Identification of FAM111A as an SV40 host range restriction and adenovirus helper factor.

    Directory of Open Access Journals (Sweden)

    Debrah A Fine

    Full Text Available The small genome of polyomaviruses encodes a limited number of proteins that are highly dependent on interactions with host cell proteins for efficient viral replication. The SV40 large T antigen (LT contains several discrete functional domains including the LXCXE or RB-binding motif, the DNA binding and helicase domains that contribute to the viral life cycle. In addition, the LT C-terminal region contains the host range and adenovirus helper functions required for lytic infection in certain restrictive cell types. To understand how LT affects the host cell to facilitate viral replication, we expressed full-length or functional domains of LT in cells, identified interacting host proteins and carried out expression profiling. LT perturbed the expression of p53 target genes and subsets of cell-cycle dependent genes regulated by the DREAM and the B-Myb-MuvB complexes. Affinity purification of LT followed by mass spectrometry revealed a specific interaction between the LT C-terminal region and FAM111A, a previously uncharacterized protein. Depletion of FAM111A recapitulated the effects of heterologous expression of the LT C-terminal region, including increased viral gene expression and lytic infection of SV40 host range mutants and adenovirus replication in restrictive cells. FAM111A functions as a host range restriction factor that is specifically targeted by SV40 LT.

  7. [Study on restriction factors and countermeasures of influence of China medical devices competitiveness].

    Science.gov (United States)

    Zhang, Zhijun

    2012-07-01

    Recent years, China medical devices industry has been a sunrise industry with widely-ranged products, high-tech innovation, and booming market demands. But with the globalization of market economy, China industry is still in the inferior position of competition. How to promote the industrial structure transition, increase scientific and technological level, speed up the updating of products, enhance the international competitiveness is one of the major tasks to maintain the healthy development of industry. This article makes a study on current situation of China medical devices industry, analyses the new opportunities, challenges and restriction factors, provides the countermeasures of strengthening industry competitiveness as well.

  8. Restrictive Factors of Vocational Education Development in Cultivation of Rural Practical Skilled Personnel and Countermeasures

    Institute of Scientific and Technical Information of China (English)

    Ning; WANG; Fang; LIU

    2014-01-01

    Kunming City is accelerating the process of agricultural modernization,industrialization,informationization and ecological development. In this process,it needs speeding up building new high level and advanced rural practical skilled personnel team suitable for development demand. By empirical analysis method,this paper discussed the factors restricting vocational education in cultivation of rural practical skilled personnel. Then,it came up with countermeasures in cultivation objective of rural vocational education,arrangement of specialized disciplines,key development tasks,and establishment of diversified investment system.

  9. Model identification with BPNN on restrictive ecological factors of SRB for sulfate-reduction

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The model of back-propagation neural network(BPNN)was presented to demonstrate the effect of restrictive ecological factors,COD/SO42-ratio,pH value,alkalinity(ALK)and SO42-loading rate(Ns),on sulfate-reduction of Sulfate Reducing Bacteria(SRB)in an acidogenic sulfate-reducing reactor supplied with molasses as sole organic carbon source and sodium sulfate as electron acceptor.The compare of experimental results and computer simulation was also discussed.It was shown that the method of BPNN had a powerful ability to analyze the ecological characteristic of acidogenic sulfate-reducing ecosystem quantitatively.

  10. Fibroblast growth factor 23 and the antiproteinuric response to dietary sodium restriction during renin-angiotensin-aldosterone system blockade.

    NARCIS (Netherlands)

    Humalda, J.K.; Lambers Heerspink, H.J.; Kwakernaak, A.J.; Slagman, M.C.; Waanders, F.; Vervloet, M.G.; Wee, P.M. Ter; Navis, G.; Borst, M.H. de; Wee, P.M. ter; Vervloet, M.; Bindels, R.J.; Hoenderop, J.G.J.; Hillebrands, J.L.

    2015-01-01

    BACKGROUND: Residual proteinuria during renin-angiotensin-aldosterone system (RAAS) blockade is a major renal and cardiovascular risk factor in chronic kidney disease. Dietary sodium restriction potentiates the antiproteinuric effect of RAAS blockade, but residual proteinuria remains in many patient

  11. Fibroblast Growth Factor 23 and the Antiproteinuric Response to Dietary Sodium Restriction During Renin-Angiotensin-Aldosterone System Blockade

    NARCIS (Netherlands)

    Humalda, Jelmer K; Lambers Heerspink, Hiddo J; Kwakernaak, Arjan J; Slagman, Maartje C J; Waanders, Femke; Vervloet, Marc G; Ter Wee, Pieter M; Navis, Gerarda; de Borst, Martin H

    2015-01-01

    Background: Residual proteinuria during renin-angiotensin-aldosterone system (RAAS) blockade is a major renal and cardiovascular risk factor in chronic kidney disease. Dietary sodium restriction potentiates the antiproteinuric effect of RAAS blockade, but residual proteinuria remains in many patient

  12. Analysis of the restricting factors of laser countermeasure active detection technology

    Science.gov (United States)

    Zhang, Yufa; Sun, Xiaoquan

    2016-07-01

    The detection effect of laser active detection system is affected by various kinds of factors. In view of the application requirement of laser active detection, the influence factors for laser active detection are analyzed. The mathematical model of cat eye target detection distance has been built, influence of the parameters of laser detection system and the environment on detection range and the detection efficiency are analyzed. Various parameters constraint detection performance is simulated. The results show that the discovery distance of laser active detection is affected by the laser divergence angle, the incident angle and the visibility of the atmosphere. For a given detection range, the laser divergence angle and the detection efficiency are mutually restricted. Therefore, in view of specific application environment, it is necessary to select appropriate laser detection parameters to achieve optimal detection effect.

  13. Early Life Stress and Sleep Restriction as Risk Factors in PTSD: An Integrative Pre-Clinical Approach

    Science.gov (United States)

    2015-04-01

    M., He, H., Arora, J., Lu, N., Tu, X. M. and Katz, I. R. (2014). Posttraumatic stress disorder and suicide in 5.9 million individuals receiving...Award Number: W81XWH-11-2-0111 TITLE: Early Life Stress and Sleep Restriction as Risk Factors in PTSD: An Integrative Pre-Clinical Approach...2015 4. TITLE AND SUBTITLE “Early Life Stress and Sleep Restriction as Risk Factors in PTSD: An Integrative Pre- Clinical Approach” 5a. CONTRACT NUMBER

  14. Computation of the pseudoskin factor caused by a restricted-entry well completed in a multilayer reservoir

    Energy Technology Data Exchange (ETDEWEB)

    Yeh, N.; Reynolds, A.C.

    1989-06-01

    This work considers flow to a restricted-entry well in a single- or multilayer reservoir where crossflow occurs between reservoir layers. A simple algebraic expression for approximating the pseudoskin factor caused by restricted entry is presented. It is shown that, for practical purposes, this equation yields sufficiently accurate estimates of the pseudoskin factor regardless of the location of the open interval.This work also extends single-layer results of interest in well testing to the multilayer case and shows that if sufficient data are available, the results of this work can be used to prepare a complete analysis of well testing pressure data obtained at a restricted-entry well.

  15. Insulin-like growth factor and fibroblast growth factor expression profiles in growth-restricted fetal sheep pancreas.

    Science.gov (United States)

    Chen, Xiaochuan; Rozance, Paul J; Hay, William W; Limesand, Sean W

    2012-05-01

    Placental insufficiency results in intrauterine growth restriction (IUGR), impaired fetal insulin secretion and less fetal pancreatic β-cell mass, partly due to lower β-cell proliferation rates. Insulin-like growth factors (IGFs) and fibroblast growth factors (FGFs) regulate fetal β-cell proliferation and pancreas development, along with transcription factors, such as pancreatic and duodenal homeobox 1 (PDX-1). We determined expression levels for these growth factors, their receptors and IGF binding proteins in ovine fetal pancreas and isolated islets. In the IUGR pancreas, relative mRNA expression levels of IGF-I, PDX-1, FGF7 and FGFR2IIIb were 64% (P pancreas compared with controls. In isolated islets from IUGR fetuses, IGF-II and IGFBP-2 mRNA concentrations were 1.5- and 3.7-fold greater (P < 0.05), and insulin mRNA was 56% less (P < 0.05) than control islets. The growth factor expression profiles for IGF and FGF signaling pathways indicate that declines in β-cell mass are due to decreased growth factor signals for both pancreatic progenitor epithelial cell and mature β-cell replication.

  16. Tombusvirus-yeast interactions identify conserved cell-intrinsic viral restriction factors

    Directory of Open Access Journals (Sweden)

    Zsuzsanna eSasvari

    2014-08-01

    Full Text Available To combat viral infections, plants possess innate and adaptive immune pathways, such as RNA silencing, R gene and recessive gene-mediated resistance mechanisms. However, it is likely that additional cell-intrinsic restriction factors (CIRF are also involved in limiting plant virus replication. This review discusses novel CIRFs with antiviral functions, many of them RNA-binding proteins or affecting the RNA binding activities of viral replication proteins. The CIRFs against tombusviruses have been identified in yeast (Saccharomyces cerevisiae, which is developed as an advanced model organism. Grouping of the identified CIRFs based on their known cellular functions and subcellular localization in yeast reveals that TBSV replication is limited by a wide variety of host gene functions. Yeast proteins with the highest connectivity in the network map include the well-characterized Xrn1p 5’-3’ exoribonuclease, Act1p actin protein and Cse4p centromere protein. The protein network map also reveals an important interplay between the pro-viral Hsp70 cellular chaperone and the antiviral co-chaperones, and possibly key roles for the ribosomal or ribosome-associated factors. We discuss the antiviral functions of selected CIRFs, such as the RNA binding nucleolin, ribonucleases, WW-domain proteins, single- and multi-domain cyclophilins, TPR-domain co-chaperones and cellular ion pumps. These restriction factors frequently target the RNA-binding region in the viral replication proteins, thus interfering with the recruitment of the viral RNA for replication and the assembly of the membrane-bound viral replicase. Although many of the characterized CIRFs act directly against TBSV, we propose that the TPR-domain co-chaperones function as guardians of the cellular Hsp70 chaperone system, which is subverted efficiently by TBSV for viral replicase assembly in the absence of the TPR-domain co-chaperones.

  17. Antagonism of tetherin restriction of HIV-1 release by Vpu involves binding and sequestration of the restriction factor in a perinuclear compartment.

    Directory of Open Access Journals (Sweden)

    Mathieu Dubé

    2010-04-01

    Full Text Available The Vpu accessory protein promotes HIV-1 release by counteracting Tetherin/BST-2, an interferon-regulated restriction factor, which retains virions at the cell-surface. Recent reports proposed beta-TrCP-dependent proteasomal and/or endo-lysosomal degradation of Tetherin as potential mechanisms by which Vpu could down-regulate Tetherin cell-surface expression and antagonize this restriction. In all of these studies, Tetherin degradation did not, however, entirely account for Vpu anti-Tetherin activity. Here, we show that Vpu can promote HIV-1 release without detectably affecting Tetherin steady-state levels or turnover, suggesting that Tetherin degradation may not be necessary and/or sufficient for Vpu anti-Tetherin activity. Even though Vpu did not enhance Tetherin internalization from the plasma membrane (PM, it did significantly slow-down the overall transport of the protein towards the cell-surface. Accordingly, Vpu expression caused a specific removal of cell-surface Tetherin and a re-localization of the residual pool of Tetherin in a perinuclear compartment that co-stained with the TGN marker TGN46 and Vpu itself. This re-localization of Tetherin was also observed with a Vpu mutant unable to recruit beta-TrCP, suggesting that this activity is taking place independently from beta-TrCP-mediated trafficking and/or degradation processes. We also show that Vpu co-immunoprecipitates with Tetherin and that this interaction involves the transmembrane domains of the two proteins. Importantly, this association was found to be critical for reducing cell-surface Tetherin expression, re-localizing the restriction factor in the TGN and promoting HIV-1 release. Overall, our results suggest that association of Vpu to Tetherin affects the outward trafficking and/or recycling of the restriction factor from the TGN and as a result promotes its sequestration away from the PM where productive HIV-1 assembly takes place. This mechanism of antagonism that results

  18. Hydrodynamic and Functional Analysis of HIV-1 Vif Oligomerization

    OpenAIRE

    Stephen M Techtmann; Ghirlando, Rodolfo; Kao, Sandra; Strebel, Klaus; Maynard, Ernest L.

    2012-01-01

    HIV-1 Vif is an accessory protein that induces the proteasomal degradation of the host restriction factor, apolipoprotein B mRNA-editing enzyme catalytic polypeptide-like 3G (APOBEC3G). The N-terminal half of Vif binds to APOBEC3G and the C-terminal half binds to subunits of a cullin-5-based ubiquitin ligase. This Vif-directed ubiquitin ligase induces the degradation of APOBEC3G (a cytidine deaminase), and thereby protects the viral genome from mutation. A conserved PPLP motif near the C term...

  19. Effect of age on the gene expression of neural-restrictive silencing factor NRSF/REST.

    Science.gov (United States)

    Mori, Nozomu; Mizuno, Takafumi; Murai, Kiyohito; Nakano, Itsuko; Yamashita, Hitoshi

    2002-01-01

    Aging affects a wide range of gene expression changes in the nervous system. Such effects could be attributed to random changes in the environment with age around each gene, but also could be caused by selective changes in a limited set of key regulatory transcription factors and/or chromatin remodeling components. To approach the question of whether neural-restrictive silencer factor NRSF, a key determinant of the neuron-specific gene expression, is involved in these changes, we examined the levels of NRSF in the rat brain and dosal root ganglia during aging by semi-quantitative reverse transcriptase-mediated polymerase chain reaction (PCR) (RT-PCR). Complementary expression profiles of transcripts of NRSF and SCG10 in the mature brain were shown by in situ hybridization. Neither the mRNA levels of NRSF nor a splicing variant NRnV were changed, at least in rats up to 26 months old. The gene expression level of SCG10, one of the NRSF targets, was also unaffected by age. The stable expression of SCG10 transcripts in aging was confirmed by in situ hybridization. The NRS-binding ability of NRSF was also unchanged significantly in the nuclear extracts of aged rat brain. These results suggest that the genetic machinery associated with the NRS-NRSF system is well maintained during aging.

  20. Hypoxia-inducible factor-1a restricts the anabolic actions of parathyroid hormone

    Institute of Scientific and Technical Information of China (English)

    Julie L Frey; David P Stonko; Marie-Claude Faugere; Ryan C Riddle

    2014-01-01

    The hypoxia inducible factors (Hifs) are evolutionarily conserved transcriptional factors that control homeostatic responses to low oxygen. In developing bone, Hif-1 generated signals induce angiogenesis necessary for osteoblast specification, but in mature bone, loss of Hif-1 in osteoblasts resulted in a more rapid accumulation of bone. These findings suggested that Hif-1 exerts distinct developmental functions and acts as a negative regulator of bone formation. To investigate the function of Hif-1a in osteoanabolic signaling, we assessed the effect of Hif-1a loss-of-function on bone formation in response to intermittent parathyroid hormone (PTH). Mice lacking Hif-1a in osteoblasts and osteocytes form more bone in response to PTH, likely through a larger increase in osteoblast activity and increased sensitivity to the hormone. Consistent with this effect, exposure of primary mouse osteoblasts to PTH resulted in the rapid induction of Hif-1a protein levels via a post-transcriptional mechanism. The enhanced anabolic response appears to result from the removal of Hif-1a-mediated suppression of b-catenin transcriptional activity. Together, these data indicate that Hif-1a functions in the mature skeleton to restrict osteoanabolic signaling. The availability of pharmacological agents that reduce Hif-1a function suggests the value in further exploration of this pathway to optimize the therapeutic benefits of PTH.

  1. Two genetic determinants acquired late in Mus evolution regulate the inclusion of exon 5, which alters mouse APOBEC3 translation efficiency.

    Directory of Open Access Journals (Sweden)

    Jun Li

    2012-01-01

    Full Text Available Mouse apolipoprotein B mRNA-editing enzyme catalytic polypeptide-like editing complex 3 (mA3, an intracellular antiviral factor, has 2 allelic variations that are linked with different susceptibilities to beta- and gammaretrovirus infections among various mouse strains. In virus-resistant C57BL/6 (B6 mice, mA3 transcripts are more abundant than those in susceptible BALB/c mice both in the spleen and bone marrow. These strains of mice also express mA3 transcripts with different splicing patterns: B6 mice preferentially express exon 5-deficient (Δ5 mA3 mRNA, while BALB/c mice produce exon 5-containing full-length mA3 mRNA as the major transcript. Although the protein product of the Δ5 mRNA exerts stronger antiretroviral activities than the full-length protein, how exon 5 affects mA3 antiviral activity, as well as the genetic mechanisms regulating exon 5 inclusion into the mA3 transcripts, remains largely uncharacterized. Here we show that mA3 exon 5 is indeed a functional element that influences protein synthesis at a post-transcriptional level. We further employed in vitro splicing assays using genomic DNA clones to identify two critical polymorphisms affecting the inclusion of exon 5 into mA3 transcripts: the number of TCCT repeats upstream of exon 5 and the single nucleotide polymorphism within exon 5 located 12 bases upstream of the exon 5/intron 5 boundary. Distribution of the above polymorphisms among different Mus species indicates that the inclusion of exon 5 into mA3 mRNA is a relatively recent event in the evolution of mice. The widespread geographic distribution of this exon 5-including genetic variant suggests that in some Mus populations the cost of maintaining an effective but mutagenic enzyme may outweigh its antiviral function.

  2. Suture restriction of the temporal bone as a risk factor for acute otitis media in children: cohort study

    Directory of Open Access Journals (Sweden)

    Morin Chantal

    2012-11-01

    Full Text Available Abstract Background Eustachian tube (ET dysfunction plays an important role in the pathogenesis of acute otitis media (AOM. Unfortunately, there is a lack of knowledge about the exact role of the ET’s bony support, the temporal bone, on occurrence of AOM. This study investigates whether severe suture restriction of the temporal bone is a risk factor for development of AOM in young children. Methods Using a prospective cohort design, 64 children aged 6 to 18 months without prior history of AOM were followed during the cold season (September 2009 to April 2010. Temporal bone status (categorized as with or without severe suture restriction was evaluated using palpation and a cranial bone mobility test. Information about potential baseline confounders and risk factors for AOM (gender, age, birth weight, gestational age, use of pacifier, daycare attendance, presence of siblings, low socioeconomic status, breastfeeding ≥ 6 months, parental smoking and history of upper respiratory tract infection were also collected. Occurrence of AOM diagnosed by physicians blinded to temporal bone status was the main outcome. Data were analyzed using hierarchical linear and nonlinear (multilevel models. Results Severe suture restriction of the temporal bone was identified in 23 children (35.9%. At least one AOM episode was diagnosed in 14 (48.3% of the ears associated with temporal bones previously identified as having severe suture restriction and in 28 (28.3% of those without severe suture restriction. Higher risk for AOM was explained by severe suture restriction of the temporal bone (adjusted relative risk (RR, 2.26, 95% CI 1.43 to 2.91, p Conclusions The study results indicate that severe suture restriction of the temporal bone is a risk factor for AOM in young children. Subsequent intervention studies are needed to determine if this mechanical risk factor can be modified in young children.

  3. Brain-derived neurotrophic factor deficiency restricts proliferation of oligodendrocyte progenitors following cuprizone-induced demyelination.

    Science.gov (United States)

    Tsiperson, Vladislav; Huang, Yangyang; Bagayogo, Issa; Song, Yeri; VonDran, Melissa W; DiCicco-Bloom, Emanuel; Dreyfus, Cheryl F

    2015-01-01

    Brain-derived neurotrophic factor (BDNF) is a member of the neurotrophin family of growth factors that through its neurotrophic tyrosine kinase, receptor, type 2 (TrkB) receptor, increases 5-bromo-2-deoxyuridine incorporation in oligodendrocyte progenitor cells (OPCs) in culture. Roles in vivo are less well understood; however, increases in numbers of OPCs are restricted in BDNF+/- mice following cuprizone-elicited demyelination. Here, we investigate whether these blunted increases in OPCs are associated with changes in proliferation. BDNF+/+ and BDNF+/- mice were fed cuprizone-containing or control feed. To assess effects on OPC numbers, platelet-derived growth factor receptor alpha (PDGFRα)+ or NG2+ cells were counted. To monitor DNA synthesis, 5-ethynyl-2'-deoxyuridine (EdU) was injected intraperitoneally and colocalized with PDGFRα+ cells. Alternatively, proliferating cell nuclear antigen (PCNA) was colocalized with PDGFRα or NG2. Labeling indices were determined in the BDNF+/+ and BDNF+/- animals. After 4 or 5 weeks of control feed, BDNF+/- mice exhibit similar numbers of OPCs compared with BDNF+/+ animals. The labeling indices for EdU and PCNA also were not significantly different, suggesting that neither the DNA synthesis phase (S phase) nor the proliferative pool size was different between genotypes. In contrast, when mice were challenged by cuprizone for 4 or 5 weeks, increases in OPCs observed in BDNF+/+ mice were reduced in the BDNF+/- mice. This difference in elevations in cell number was accompanied by decreases in EdU labeling and PCNA labeling without changes in cell death, indicating a reduction in the DNA synthesis and the proliferative pool. Therefore, levels of BDNF influence the proliferation of OPCs resulting from a demyelinating lesion.

  4. Severe Calorie Restriction Reduces Cardiometabolic Risk Factors and Protects Rat Hearts from Ischemia/Reperfusion Injury

    Science.gov (United States)

    Melo, Dirceu S.; Costa-Pereira, Liliane V.; Santos, Carina S.; Mendes, Bruno F.; Costa, Karine B.; Santos, Cynthia Fernandes F.; Rocha-Vieira, Etel; Magalhães, Flávio C.; Esteves, Elizabethe A.; Ferreira, Anderson J.; Guatimosim, Sílvia; Dias-Peixoto, Marco F.

    2016-01-01

    Background and Aims: Recent studies have proposed that if a severe caloric restriction (SCR) is initiated at the earliest period of postnatal life, it can lead to beneficial cardiac adaptations later on. We investigated the effects of SCR in Wistar rats from birth to adult age on risk factors for cardiac diseases (CD), as well as cardiac function, redox status, and HSP72 content in response to ischemia/reperfusion (I/R) injury. Methods and Results: From birth to the age of 3 months, CR50 rats were fed 50% of the food that the ad libitum group (AL) was fed. Food intake was assessed daily and body weight were assessed weekly. In the last week of the SCR protocol, systolic blood pressure and heart rate were measured and the double product index was calculated. Also, oral glucose and intraperitoneal insulin tolerance tests were performed. Thereafter, rats were decapitated, visceral fat was weighed, and blood and hearts were harvested for biochemical, functional, tissue redox status, and western blot analyzes. Compared to AL, CR50 rats had reduced the main risk factors for CD. Moreover, the FR50 rats showed increased cardiac function both at baseline conditions (45% > AL rats) and during the post-ischemic period (60% > AL rats) which may be explained by a decreased cardiac oxidative stress and increased HSP72 content. Conclusion: SCR from birth to adult age reduced risk factors for CD, increased basal cardiac function and protected hearts from the I/R, possibly by a mechanism involving ROS. PMID:27092082

  5. Is abnormal vaginal microflora a risk factor for intrauterine fetal growth restriction?

    Institute of Scientific and Technical Information of China (English)

    NatalijaVedmedovska; Dace Rezeberga; GilbertG G Donders

    2015-01-01

    Objective:To conduct a literature review in search of possible preventable causes for fetal growth restriction.Methods:We performed a systematic literature search regarding abnormal vaginal microflora and fetal growth encompassing the last 27-year (starting from 1986) in PubMed, Embase, and Cochrane Central to study the evidence that abnormal vaginal microflora is may be related to diminished fetal growth or small for date birth.Results:Most of the 14 studies suggested a significant role of vaginal organisms in impaired fetal growth, unrelated to preterm birth. The neonatal outcome has shown to be largely linked to the preventable or foreseeable fetal factors, such as genetic abnormalities, but also ascending intrauterine infections. Our previous work suggested a role of vaginal organisms in adverse pregnancy outcome, not only preterm birth, but also impaired fetal growth.Conclusions:There is a need for cohort studies designed to unravel this link between abnormal microflora and FGR, in order to enable preventive actions to protect these small babies from severe damage and death by early screening and treatment.

  6. Intrauterine growth restriction: distribution, risk factors, management of labour and outcome

    Directory of Open Access Journals (Sweden)

    Diana Andzane

    2015-08-01

    Full Text Available Background: The development of Intrauterine growth restriction (IUGR determines maternal, fetal and placental factors. Many of these factors are preventable. There is still no enough developed effective pregnancy and labour management tactics that could protect both mother and child from the unintended consequences. Methods: The research was made in Riga Maternity Hospital. In the research there were included pregnant women who gave birth neonates with weight under 10th percentile (IUGR group as well there was compiled the control group. The weight of neonates was evaluated using the percentile scales - Intrauterine Growth Curves based on US data. Results: According to the criteria, in the IUGR group were included 209 pregnant women and in the control group was the same number of patients. In the IUGR group mothers discharged from the hospital one day later than it was in the control group both after vaginal delivery (4.0 +/- 1.5 vs. 3.3 +/- 1.0, p and #706;0.0001 and after caesarean (5.6 +/- 1.5 vs. 4.5 +/- 1.0, p=0.0001. Comparing the evaluations after Apgar scale after spontaneous birth, induced labour and caesarean it was discovered that there is no statistically significant difference. Conclusions: IUGR negatively affect not just the fetus but also the mother and this is the reason why she should stay in the hospital for a longer period due to the child or experience the caesarean. [Int J Reprod Contracept Obstet Gynecol 2015; 4(4.000: 1117-1121

  7. Factors that restrict intestinal cell permeation of cyclic prodrugs of an opioid peptide (DADLE)

    DEFF Research Database (Denmark)

    Ouyang, Hui; Chen, Weiqing; Andersen, Thomas E;

    2009-01-01

    The objective of this study was to determine the relative importance of metabolism by cytochrome P450 (CYP) enzymes versus efflux by P-glycoprotein (P-gp) in restricting the intestinal mucosal permeation of cyclic prodrugs (AOA-DADLE, CA-DADLE, OMCA-DADLE) of the opioid peptide DADLE (H......-gp), not metabolic enzymes (e.g., CYP 3A, esterases), restrict the permeation of peptide prodrugs across the rat intestinal mucosa....

  8. Restricted maternal nutrition alters myogenic regulatory factor expression in satellite cells of ovine offspring.

    Science.gov (United States)

    Raja, J S; Hoffman, M L; Govoni, K E; Zinn, S A; Reed, S A

    2016-07-01

    Poor maternal nutrition inhibits muscle development and postnatal muscle growth. Satellite cells are myogenic precursor cells that contribute to postnatal muscle growth, and their activity can be evaluated by the expression of several transcription factors. Paired-box (Pax)7 is expressed in quiescent and active satellite cells. MyoD is expressed in activated and proliferating satellite cells and myogenin is expressed in terminally differentiating cells. Disruption in the expression pattern or timing of expression of myogenic regulatory factors negatively affects muscle development and growth. We hypothesized that poor maternal nutrition during gestation would alter the in vitro temporal expression of MyoD and myogenin in satellite cells from offspring at birth and 3 months of age. Ewes were fed 100% or 60% of NRC requirements from day 31±1.3 of gestation. Lambs from control-fed (CON) or restricted-fed (RES) ewes were euthanized within 24 h of birth (birth; n=5) or were fed a control diet until 3 months of age (n=5). Satellite cells isolated from the semitendinosus muscle were used for gene expression analysis or cultured for 24, 48 or 72 h and immunostained for Pax7, MyoD or myogenin. Fusion index was calculated from a subset of cells allowed to differentiate. Compared with CON, temporal expression of MyoD and myogenin was altered in cultured satellite cells isolated from RES lambs at birth. The percent of cells expressing MyoD was greater in RES than CON (P=0.03) after 24 h in culture. After 48 h of culture, there was a greater percent of cells expressing myogenin in RES compared with CON (P0.05). In satellite cells from RES lambs at 3 months of age, the percent of cells expressing MyoD and myogenin were greater than CON after 72 h in culture (Psatellite cells of the offspring, which may reduce the pool of myoblasts, decrease myoblast fusion and contribute to the poor postnatal muscle growth previously observed in these animals.

  9. Characterization and restriction analysis of the P sex factor and the cryptic plasmid of Vibrio cholerae strain V58.

    Science.gov (United States)

    Bartowsky, E J; Morelli, G; Kamke, M; Manning, P A

    1987-07-01

    The P plasmid of Vibrio cholerae is a derepressed sex factor restricted to V. cholerae and has been shown to express surface exclusion. We have isolated the plasmids of strain V58 and have found that in addition to P, two further cryptic plasmids are also present. P has a size of 68 kb as determined by both electron microscopy and restriction endonuclease analysis. These other plasmids are 34 and 4.7 kb in size. Restriction maps of P and the larger cryptic plasmid have been determined. It has been demonstrated that P differs from the standard Inc group test plasmids and also expresses a surface exclusion system. The ability of the type Inc plasmids to be transferred to V. cholerae by either liquid or filter matings and the stability of these plasmids in V. cholerae have also been examined.

  10. Research Progress in HIV Auxiliary Proteins Counteracting Host Restriction Factors%HIV辅助蛋白拮抗细胞限制因子机制研究进展

    Institute of Scientific and Technical Information of China (English)

    陈倩倩; 徐庆刚; 张驰宇

    2014-01-01

    抗病毒限制因子成为病毒学研究领域的热点.近些年陆续发现了4种HIV限制因子:APOBEC3G、Trim5α、Tetherin、SAMHD1.其中APOBEC3G、Tetherin、SAMHD1分别被HIV编码的辅助蛋白Vif、Vpu、Vpx所拮抗.这些辅助蛋白影响病毒的致病性和复制能力,拮抗宿主内的天然抗病毒限制因子,使病毒能够成功的侵染宿主细胞.本文重点综述了这三种能拮抗宿主限制因子的HIV辅助蛋白的功能研究进展.

  11. Endogenous Murine BST-2/Tetherin Is Not a Major Restriction Factor of Influenza A Virus Infection.

    Directory of Open Access Journals (Sweden)

    Sarah L Londrigan

    Full Text Available BST-2 (tetherin, CD317, HM1.24 restricts virus growth by tethering enveloped viruses to the cell surface. The role of BST-2 during influenza A virus infection (IAV is controversial. Here, we assessed the capacity of endogenous BST-2 to restrict IAV in primary murine cells. IAV infection increased BST-2 surface expression by primary macrophages, but not alveolar epithelial cells (AEC. BST-2-deficient AEC and macrophages displayed no difference in susceptibility to IAV infection relative to wild type cells. Furthermore, BST-2 played little role in infectious IAV release from either AEC or macrophages. To examine BST-2 during IAV infection in vivo, we infected BST-2-deficient mice. No difference in weight loss or in viral loads in the lungs and/or nasal tissues were detected between BST-2-deficient and wild type animals. This study rules out a major role for endogenous BST-2 in modulating IAV in the mouse model of infection.

  12. A Highly Active Isoform of Lentivirus Restriction Factor SAMHD1 in Mouse.

    Science.gov (United States)

    Bloch, Nicolin; Gläsker, Sabine; Sitaram, Poojitha; Hofmann, Henning; Shepard, Caitlin N; Schultz, Megan L; Kim, Baek; Landau, Nathaniel R

    2017-01-20

    The triphosphohydrolase SAMHD1 (sterile α motif and histidine-aspartate domain-containing protein 1) restricts HIV-1 replication in nondividing myeloid cells by depleting the dNTP pool, preventing reverse transcription. SAMHD1 is also reported to have ribonuclease activity that degrades the virus genomic RNA. Human SAMHD1 is regulated by phosphorylation of its carboxyl terminus at Thr-592, which abrogates its antiviral function yet has only a small effect on its phosphohydrolase activity. In the mouse, SAMHD1 is expressed as two isoforms (ISF1 and ISF2) that differ at the carboxyl terminus due to alternative splicing of the last coding exon. In this study we characterized the biochemical and antiviral properties of the two mouse isoforms of SAMHD1. Both are antiviral in nondividing cells. Mass spectrometry analysis showed that SAMHD1 is phosphorylated at several amino acid residues, one of which (Thr-634) is homologous to Thr-592. Phosphomimetic mutation at Thr-634 of ISF1 ablates its antiviral activity yet has little effect on phosphohydrolase activity in vitro dGTP caused ISF1 to tetramerize, activating its catalytic activity. In contrast, ISF2, which lacks the phosphorylation site, was significantly more active, tetramerized, and was active without added dGTP. Neither isoform nor human SAMHD1 had detectable RNase activity in vitro or affected HIV-1 genomic RNA stability in newly infected cells. These data support a model in which SAMHD1 catalytic activity is regulated through tetramer stabilization by the carboxyl-terminal tail, phosphorylation destabilizing the complexes and inactivating the enzyme. ISF2 may serve to reduce the dNTP pool to very low levels as a means of restricting virus replication.

  13. NcoI restriction fragment length polymorphism (RFLP) of the tumour necrosis factor (TNF alpha) region in primary biliary cirrhosis and in healthy Danes

    DEFF Research Database (Denmark)

    Fugger, L; Morling, N; Ryder, L P;

    1989-01-01

    The restriction fragment length polymorphism of the human tumour necrosis factor (TNF alpha) region was investigated by means of 20 different restriction enzymes and a human TNF alpha cDNA probe. Only one of the enzymes, NcoI, revealed a polymorphic pattern consisting of fragments of 10.5 and 5...

  14. Local sequence targeting in the AID/APOBEC family differentially impacts retroviral restriction and antibody diversification.

    Science.gov (United States)

    Kohli, Rahul M; Maul, Robert W; Guminski, Amy F; McClure, Rhonda L; Gajula, Kiran S; Saribasak, Huseyin; McMahon, Moira A; Siliciano, Robert F; Gearhart, Patricia J; Stivers, James T

    2010-12-24

    Nucleic acid cytidine deaminases of the activation-induced deaminase (AID)/APOBEC family are critical players in active and innate immune responses, playing roles as target-directed, purposeful mutators. AID specifically deaminates the host immunoglobulin (Ig) locus to evolve antibody specificity, whereas its close relative, APOBEC3G (A3G), lethally mutates the genomes of retroviral pathogens such as HIV. Understanding the basis for the target-specific action of these enzymes is essential, as mistargeting poses significant risks, potentially promoting oncogenesis (AID) or fostering drug resistance (A3G). AID prefers to deaminate cytosine in WRC (W = A/T, R = A/G) motifs, whereas A3G favors deamination of CCC motifs. This specificity is largely dictated by a single, divergent protein loop in the enzyme family that recognizes the DNA sequence. Through grafting of this substrate-recognition loop, we have created enzyme variants of A3G and AID with altered local targeting to directly evaluate the role of sequence specificity on immune function. We find that grafted loops placed in the A3G scaffold all produced efficient restriction of HIV but that foreign loops in the AID scaffold compromised hypermutation and class switch recombination. Local targeting, therefore, appears alterable for innate defense against retroviruses by A3G but important for adaptive antibody maturation catalyzed by AID. Notably, AID targeting within the Ig locus is proportionally correlated to its in vitro ability to target WRC sequences rather than non-WRC sequences. Although other mechanisms may also contribute, our results suggest that local sequence targeting by AID/APOBEC3 enzymes represents an elegant example of co-evolution of enzyme specificity with its target DNA sequence.

  15. Structural basis for antagonizing a host restriction factor by C7 family of poxvirus host-range proteins.

    Science.gov (United States)

    Meng, Xiangzhi; Krumm, Brian; Li, Yongchao; Deng, Junpeng; Xiang, Yan

    2015-12-01

    Human sterile alpha motif domain-containing 9 (SAMD9) protein is a host restriction factor for poxviruses, but it can be overcome by some poxvirus host-range proteins that share homology with vaccinia virus C7 protein. To understand the mechanism of action for this important family of host-range factors, we determined the crystal structures of C7 and myxoma virus M64, a C7 family member that is unable to antagonize SAMD9. Despite their different functions and only 23% sequence identity, the two proteins have very similar overall structures, displaying a previously unidentified fold comprised of a compact 12-stranded antiparallel β-sandwich wrapped in two short α helices. Extensive structure-guided mutagenesis of C7 identified three loops clustered on one edge of the β sandwich as critical for viral replication and binding with SAMD9. The loops are characterized with functionally important negatively charged, positively charged, and hydrophobic residues, respectively, together forming a unique "three-fingered molecular claw." The key residues of the claw are not conserved in two C7 family members that do not antagonize SAMD9 but are conserved in distantly related C7 family members from four poxvirus genera that infect diverse mammalian species. Indeed, we found that all in the latter group of proteins bind SAMD9. Taken together, our data indicate that diverse mammalian poxviruses use a conserved molecular claw in a C7-like protein to target SAMD9 and overcome host restriction.

  16. On the Restricting Factors & System Arrangements of Chinese Land Tenure Marketization

    Institute of Scientific and Technical Information of China (English)

    YU Peng-yi; ZHANG Wei-dong

    2003-01-01

    As a general rule of Economics of Development,economic growth and development require rational institution guarantee.Land Tenure.As a main institution factor in agricultural development,closely relates to the reform of Chinese agriculture.Based on the relevant theories of Economics of Institution and Economics of Development,and combined with the marketization process of Chinese Land Tenure of Property Rights,the article studied the effects of institutional factors and put forward some choices in the development of agriculture,which is of both significant and practical importance.

  17. DNA methylation restricts lineage-specific functions of transcription factor Gata4 during embryonic stem cell differentiation.

    Directory of Open Access Journals (Sweden)

    Masaaki Oda

    2013-06-01

    Full Text Available DNA methylation changes dynamically during development and is essential for embryogenesis in mammals. However, how DNA methylation affects developmental gene expression and cell differentiation remains elusive. During embryogenesis, many key transcription factors are used repeatedly, triggering different outcomes depending on the cell type and developmental stage. Here, we report that DNA methylation modulates transcription-factor output in the context of cell differentiation. Using a drug-inducible Gata4 system and a mouse embryonic stem (ES cell model of mesoderm differentiation, we examined the cellular response to Gata4 in ES and mesoderm cells. The activation of Gata4 in ES cells is known to drive their differentiation to endoderm. We show that the differentiation of wild-type ES cells into mesoderm blocks their Gata4-induced endoderm differentiation, while mesoderm cells derived from ES cells that are deficient in the DNA methyltransferases Dnmt3a and Dnmt3b can retain their response to Gata4, allowing lineage conversion from mesoderm cells to endoderm. Transcriptome analysis of the cells' response to Gata4 over time revealed groups of endoderm and mesoderm developmental genes whose expression was induced by Gata4 only when DNA methylation was lost, suggesting that DNA methylation restricts the ability of these genes to respond to Gata4, rather than controlling their transcription per se. Gata4-binding-site profiles and DNA methylation analyses suggested that DNA methylation modulates the Gata4 response through diverse mechanisms. Our data indicate that epigenetic regulation by DNA methylation functions as a heritable safeguard to prevent transcription factors from activating inappropriate downstream genes, thereby contributing to the restriction of the differentiation potential of somatic cells.

  18. Identification of repressor element 1 in cytochrome P450 genes and their negative regulation by RE1 silencing transcription factor/neuron-restrictive silencer factor.

    Science.gov (United States)

    García-Sánchez, Rubén; Ayala-Luján, Jorge; Hernández-Peréz, Ascensión; Mendoza-Figueroa, Tomás; Tapia-Ramírez, José

    2003-03-17

    RE1 silencing transcription factor/neuron-restrictive silencing factor (REST/NRSF) mediates transcriptional repression in many neuron-specific genes by interaction with the repressor element 1/neuron-restrictive silencing element (RE1/NRSE). This element has been identified at least in 20 neuron specific genes. REST/NRSF is highly expressed in non-neuronal tissues, where it is thought to repress gene transcription. We performed a BLAST search to look for the presence of RE1/NRSE elements in the rat cytochrome P450 genes. We identified the presence of RE1/NRSE element in the cytochrome P450 genes CYP1A1, 2A2, 2E1 and 3A2. Electrophoretic mobility shift assay and supershift assays were carried out to prove functionality of these sites and detect the interaction of REST/NRSF with this sequence. Cotransfection studies in PC12 cells with a plasmid containing the RE1 element of the CYP genes, cloned upstream of the minimal type II sodium channel promoter, in the presence of REST/NRSF, showed a marked expression inhibition of the CAT reporter gene. These data suggest that the RE1 elements that exist in these four CYP genes might be a target for the REST/NRSF transcription factor and such an interaction might play a role in the negative regulation of these genes.

  19. Familial partial lipodystrophy, mandibuloacral dysplasia and restrictive dermopathy feature barrier-to-autointegration factor (BAF) nuclear redistribution.

    Science.gov (United States)

    Capanni, Cristina; Squarzoni, Stefano; Cenni, Vittoria; D'Apice, Maria Rosaria; Gambineri, Alessandra; Novelli, Giuseppe; Wehnert, Manfred; Pasquali, Renato; Maraldi, Nadir M; Lattanzi, Giovanna

    2012-10-01

    Prelamin A processing impairment is a common feature of a restricted group of rare genetic alterations/disorders associated with a wide range of clinical phenotypes. Changes in histone posttranslational modifications, alterations in non-histone chromatin proteins and chromatin disorganization have been specifically linked to impairment of specific, distinct prelamin A processing steps, but the molecular mechanism involved in these processes is not yet understood . In this study, we show that the accumulation of wild-type prelamin A detected in restrictive dermopathy (RD), as well as the accumulation of mutated forms of prelamin A identified in familial partial lipodystrophy (FPLD) and mandibuloacral dysplasia (MADA), affect the nuclear localization of barrier-to-autointegration factor (BAF), a protein able to link lamin A precursor to chromatin remodeling functions. Our findings, in accordance with previously described results, support the hypothesis of a prelamin A involvement in BAF nuclear recruitment and suggest BAF-prelamin A complex as a protein platform usually activated in prelamin A-accumulating diseases. Finally, we demonstrate the involvement of the inner nuclear membrane protein emerin in the proper localization of BAF-prelamin A complex.

  20. Identification of human leukemia antigen A*0201-restricted epitopes derived from epidermal growth factor pathway substrate number 8.

    Science.gov (United States)

    Tang, Baishan; Zhou, Weijun; Du, Jingwen; He, Yanjie; Li, Yuhua

    2015-08-01

    T-cell-mediated immunotherapy of hematological malignancies requires selection of targeted tumor-associated antigens and T-cell epitopes contained in these tumor proteins. Epidermal growth factor receptor pathway substrate 8 (EPS8), whose function is pivotal for tumor proliferation, progression and metastasis, has been found to be overexpressed in most human tumor types, while its expression in normal tissue is low. The aim of the present study was to identify human leukemia antigen (HLA)-A*0201-restricted epitopes of EPS8 by using a reverse immunology approach. To achieve this, computer algorithms were used to predict HLA-A*0201 molecular binding, proteasome cleavage patterns as well as translocation of transporters associated with antigen processing. Candidate peptides were experimentally validated by T2 binding affinity assay and brefeldin-A decay assay. The functional avidity of peptide-specific cytotoxic T lymphocytes (CTLs) induced from peripheral blood mononuclear cells of healthy volunteers were evaluated by using an enzyme-linked immunosorbent spot assay and a cytotoxicity assay. Four peptides, designated as P455, P92, P276 and P360, had high affinity and stability of binding towards the HLA-A*0201 molecule, and specific CTLs induced by them significantly responded to the corresponding peptides and secreted IFN-γ. At the same time, the CTLs were able to specifically lyse EPS8-expressing cell lines in an HLA-A*0201-restricted manner. The present study demonstrated that P455, P92, P276 and P360 were CTL epitopes of EPS8, and were able to be used for epitope-defined adoptive T-cell transfer and multi-epitope-based vaccine design.

  1. Repressor element-1 silencing transcription factor/neuronal restrictive silencer factor (REST/NRSF can regulate HSV-1 immediate-early transcription via histone modification

    Directory of Open Access Journals (Sweden)

    Hill James M

    2007-06-01

    Full Text Available Abstract Background During primary infection of its human host, Herpes Simplex Virus Type-1 (HSV-1 establishes latency in neurons where the viral genome is maintained in a circular form associated with nucleosomes in a chromatin configration. During latency, most viral genes are silenced, although the molecular mechanisms responsible for this are unclear. We hypothesized that neuronal factors repress HSV-1 gene expression during latency. A search of the HSV-1 DNA sequence for potential regulatory elements identified a Repressor Element-1/Neuronal Restrictive Silencer Element (RE-1/NRSE located between HSV-1 genes ICP22 and ICP4. We predicted that the Repressor Element Silencing Transcription Factor/Neuronal Restrictive Silencer Factor (REST/NRSF regulates expression of ICP22 and ICP4. Results Transient cotransfection indicated that REST/NRSF inhibited the activity of both promoters. In contrast, cotransfection of a mutant form of REST/NRSF encoding only the DNA-binding domain of the protein resulted in less inhibition. Stably transformed cell lines containing episomal reporter plasmids with a chromatin structure showed that REST/NRSF specifically inhibited the ICP4 promoter, but not the ICP22 promoter. REST/NRSF inhibition of the ICP4 promoter was reversed by histone deacetylase (HDAC inhibitor Trichostatin A (TSA. Additionally, chromatin immuno-precipitation (ChIP assays indicated that the corepressor CoREST was recruited to the proximity of ICP4 promoter and that acetylation of histone H4 was reduced in the presence of REST/NRSF. Conclusion Since the ICP4 protein is a key transactivator of HSV-1 lytic cycle genes, these results suggest that REST/NRSF may have an important role in the establishment and/or maintenance of HSV-1 gene silencing during latency by targeting ICP4 expression.

  2. Analysis of Immunological, Viral, Genetic, and Environmental Factors That Might Be Associated with Decreased Susceptibility to HIV Infection in Serodiscordant Couples in Florianópolis, Southern Brazil.

    Science.gov (United States)

    Santos, Íris M; da Rosa, Elis A; Gräf, Tiago; Ferreira, Luiz G E; Petry, Andrea; Cavalheiro, Fernanda; Reiche, Edna M; Zanetti, Carlos R; Pinto, Aguinaldo R

    2015-11-01

    Individuals who have been exposed to human immunodeficiency virus (HIV) and have not been infected might possess natural resistance mechanisms. An understanding of the sociodemographic and immunological conditions that influence resistance to HIV is a challenge, and very little is known about the role of intrinsic antiviral factors that restrict HIV infection. The aim of this study was to analyze potential factors responsible for resistance to HIV infection in serodiscordant couples by comparing HIV-exposed seronegative individuals (HESN) to HIV-seropositive individuals treated with antiretroviral therapy (HIV-ART) along with healthy controls (HC). The results revealed one HLA-B*27 and two HLA-B*57 individuals among the HESN; a CCR5Δ32 heterozygous deletion was observed in one serodiscordant couple, while the homozygous genotype for this variant was not observed. There were no differences in the basal mRNA expression of APOBEC3G, CFLAR, TRIM5α, LEDGF/p75, BST-2, or SAMHD1 in CD4(+) T lymphocyte- and monocyte-enriched populations among the three groups, and lower HBD-3 concentrations were observed in saliva from HIV-ART compared to HESN and HC. The most prevalent HIV-1 subtype was C or C-containing recombinant forms. Six HIV-ART individuals and one HIV-ART individual were infected with the R5 HIV and X4 HIV strains, respectively. The ability to control infection or delay disease progression is probably defined by a balance between viral and host factors, and further evaluation should be performed in larger cohorts. Our data suggest that susceptibility to HIV infection varies among individuals and strengthens the multifactorial characteristics underlying the resistance mechanisms in HIV.

  3. In vitro and in vivo analyses of a genetically—restricted antigen specific factor from mixed cell cultures of macrophage,T and B lymphocytes

    Institute of Scientific and Technical Information of China (English)

    CHAURMW; LAUASK

    1990-01-01

    An immunostimulatory factor was identified to be secreted by antigen-pulsed macrophages.This factor was able to induce the generation of antigen specific T helper lymphocytes in vitro as well as in vivo.Further in vitro experiments testing for the genetic restriction of this factor indicated that it is a geneticallyrestricted antigen specific factor (ASF).The Cunningham plaque assay was used to quantify the generation of T helper lymphocytes by measuring the number of plaque forming cells after sequential incubations of antigen-qulsed macrophages with T lymphocytes,and then spleen cells,and finally the TNP-coated sheep red blood cells.

  4. The ubiquitin ligase TRIM27 functions as a host restriction factor antagonized by Mycobacterium tuberculosis PtpA during mycobacterial infection

    Science.gov (United States)

    Wang, Jing; Teng, Jade L. L.; Zhao, Dongdong; Ge, Pupu; Li, Bingxi; Woo, Patrick C. Y.; Liu, Cui Hua

    2016-01-01

    Macrophage-mediated innate immune responses play crucial roles in host defense against pathogens. Recent years have seen an explosion of host proteins that act as restriction factors blocking viral replication in infected cells. However, the essential factors restricting Mycobacterium tuberculosis (Mtb) and their regulatory roles during mycobacterial infection remain largely unknown. We previously reported that Mtb tyrosine phosphatase PtpA, a secreted effector protein required for intracellular survival of Mtb, inhibits innate immunity by co-opting the host ubiquitin system. Here, we identified a new PtpA-interacting host protein TRIM27, which is reported to possess a conserved RING domain and usually acts as an E3 ubiquitin ligase that interferes with various cellular processes. We further demonstrated that TRIM27 restricts survival of mycobacteria in macrophages by promoting innate immune responses and cell apoptosis. Interestingly, Mtb PtpA could antagonize TRIM27-promoted JNK/p38 MAPK pathway activation and cell apoptosis through competitively binding to the RING domain of TRIM27. TRIM27 probably works as a potential restriction factor for Mtb and its function is counteracted by Mtb effector proteins such as PtpA. Our study suggests a potential tuberculosis treatment via targeting of the TRIM27-PtpA interfaces. PMID:27698396

  5. Calorie restriction improves cognitive decline via up-regulation of brain-derived neurotrophic factor: tropomyosin-related kinase B in hippocampus ofobesity-induced hypertensive rats.

    Science.gov (United States)

    Kishi, Takuya; Hirooka, Yoshitaka; Nagayama, Tomomi; Isegawa, Kengo; Katsuki, Masato; Takesue, Ko; Sunagawa, Kenji

    2015-01-01

    In metabolic syndrome (MetS), previous studies have suggested that cognitive decline is worsened. Among the factors associated with cognition, decreased brain-derived neurotrophic factor (BDNF) in the hippocampus causes cognitive decline. We previously reported that exercise training with calorie restriction yielded protection against cognitive decline via BDNF in the hippocampus of hypertensive rats. The aim of the present study was to determine whether or not calorie restriction results in protection against cognitive decline via BDNF and its receptor tropomyosin-related kinase B (TrkB) in the hippocampus of MetS model rats. We divided dietary-induced obesity-prone and hypertensive rats (OP), as metabolic syndrome model rats, into three groups, fed with a high fat diet (HF), treated with calorie restriction (CR) plus vehicle, and treated with CR and ANA-12 (a TrkB antagonist) (CR+A). After treatment for 28 days, body weight, insulin, fasting blood glucose, adiponectin, systolic blood pressure, and oxidative stress in the hippocampus were significantly lower, and BDNF expression in the hippocampus was significantly higher in CR and CR+A than in HF. Cognitive performance determined by the Morris water maze test was significantly higher in CR than in HF, whereas the benefit was attenuated in CR+A. In conclusion, calorie restriction protects against cognitive decline via up-regulation of BDNF/TrkB through an antioxidant effect in the hippocampus of dietary-induced obesity rats.

  6. Behavioural changes are a major contributing factor in the reduction of sarcopenia in caloric-restricted ageing mice

    NARCIS (Netherlands)

    Norren, van K.; Rusli, F.; Dijk, van M.; Lute, C.; Nagel, J.C.; Dijk, F.J.; Dwarkasing, J.T.; Boekschoten, M.V.; Luiking, Y.; Witkamp, R.F.; Müller, M.R.; Steegenga, W.T.

    2015-01-01

    Background - In rodent models, caloric restriction (CR) with maintenance of adequate micronutrient supply has been reported to increase lifespan and to reduce age-induced muscle loss (sarcopenia) during ageing. In the present study, we further investigated effects of CR on the onset and severity of

  7. Hydrodynamic and functional analysis of HIV-1 Vif oligomerization.

    Science.gov (United States)

    Techtmann, Stephen M; Ghirlando, Rodolfo; Kao, Sandra; Strebel, Klaus; Maynard, Ernest L

    2012-03-13

    HIV-1 Vif is an accessory protein that induces the proteasomal degradation of the host restriction factor, apolipoprotein B mRNA-editing enzyme catalytic polypeptide-like 3G (APOBEC3G). The N-terminal half of Vif binds to APOBEC3G, and the C-terminal half binds to subunits of a cullin 5-based ubiquitin ligase. This Vif-directed ubiquitin ligase induces the degradation of APOBEC3G (a cytidine deaminase) and thereby protects the viral genome from mutation. A conserved PPLP motif near the C-terminus of Vif is essential for Vif function and is also involved in Vif oligomerization. However, the mechanism and functional significance of Vif oligomerization is unclear. We employed analytical ultracentrifugation to examine the oligomeric properties of Vif in solution. Contrary to previous reports, we find that Vif oligomerization does not require the conserved PPLP motif. Instead, our data suggest a more complex mechanism involving interactions among the HCCH motif, the BC box, and downstream residues in Vif. Mutation of residues near the PPLP motif (S165 and V166) affected the oligomeric properties of Vif and weakened the ability of Vif to bind and induce the degradation of APOBEC3G. We propose that Vif oligomerization may represent a mechanism for regulating interactions with APOBEC3G.

  8. Restricted Airspace

    Data.gov (United States)

    Federal Laboratory Consortium — Redstone Technical Test Center has restricted airspace up to 30,000 feet ASL. Airspace encompasses R-2104 (Redstone). Airspace is used extensively for airborne/UAV...

  9. Expression of human apolipoprotein B mRNA-editing catalytic polypeptide-like protein 3H hap Ⅱ in insect expression system and purification of expressed product%人APOBEC3H hap Ⅱ在昆虫表达系统中的表达及其纯化

    Institute of Scientific and Technical Information of China (English)

    李婷; 王虹; 张晓红; 董燕; 王涛; 于晓方; 韩雪

    2016-01-01

    目的 构建重组人APOBEC3H hap Ⅱ(A3H hap Ⅱ)杆状病毒表达载体,在昆虫细胞表达系统中表达,表达产物经Ni-NTA亲和层析柱纯化.方法 采用PCR方法扩增A3H hap Ⅱ基因并加入His标签后,克隆至杆状病毒转移载体pFastBac1中,转化E.coli DH10Bac感受态细胞进行重组,构建质粒Bacmid-A3H hap Ⅱ-His.将质粒转染昆虫细胞sf9获得P1病毒,扩增后获得P3病毒,感染sf9细胞表达目的蛋白,并进行Western blot鉴定.经Ni-NAT树脂亲和层析柱对表达的蛋白进行纯化,并通过免疫共沉淀试验检测A3H hap Ⅱ-His与其相互作用蛋白HIV-1 Vif之间的特异性结合.结果 成功构建了质粒Bacmid-A3H hap Ⅱ-His;P3病毒感染sf9细胞后成功表达出相对分子质量约20 000的目的蛋白,且能够与HIV-1 Vif特异性结合.结论 成功建立A3H hap Ⅱ昆虫表达体系,为进一步研究A3H hap Ⅱ与HIV-1 Vif之间的相互作用机制,并针对其相互作用位点设计抗HIV药物奠定了基础.

  10. Improvement in coronary heart disease risk factors during an intermittent fasting/calorie restriction regimen: Relationship to adipokine modulations

    Directory of Open Access Journals (Sweden)

    Kroeger Cynthia M

    2012-10-01

    Full Text Available Abstract Background The ability of an intermittent fasting (IF-calorie restriction (CR regimen (with or without liquid meals to modulate adipokines in a way that is protective against coronary heart disease (CHD has yet to be tested. Objective Accordingly, we examined the effects of an IFCR diet on adipokine profile, body composition, and markers of CHD risk in obese women. Methods Subjects (n = 54 were randomized to either the IFCR-liquid (IFCR-L or IFCR-food based (IFCR-F diet for 10 weeks. Results Greater decreases in body weight and waist circumference were noted in the IFCR-L group (4 ± 1 kg; 6 ± 1 cm versus the IFCR-F group (3 ± 1 kg; 4 ± 1 cm. Similar reductions (P Conclusion These findings suggest that IFCR with a liquid diet favorably modulates visceral fat and adipokines in a way that may confer protection against CHD.

  11. Maternal protein restriction induces alterations in hepatic tumor necrosis factor-α/CYP7A1 signaling and disorders regulation of cholesterol metabolism in the adult rat offspring.

    Science.gov (United States)

    Liu, Xiaomei; Qi, Ying; Tian, Baoling; Chen, Dong; Gao, Hong; Xi, Chunyan; Xing, Yanlin; Yuan, Zhengwei

    2014-07-01

    It is well recognized that adverse events in utero impair fetal development and lead to the development of obesity and metabolic syndrome in adulthood. To investigate the mechanisms linking impaired fetal growth to increased cholesterol, an important clinical risk factor characterizing the metabolic syndrome and cardiovascular disease, we examined the impact of maternal undernutrition on tumor necrosis factor-α (TNF-α)/c-jun N-terminal kinase (JNK) signaling pathway and the cholesterol 7α-hydroxylase (CYP7A1) expression in the livers of the offspring with a protein restriction model. The male offspring with intrauterine growth restriction (IUGR) caused by the isocaloric low-protein diet showed decreased liver weight at birth and augmented circulation and hepatic cholesterol levels at 40 weeks of age. Maternal undernutrition significantly upregulated cytokine TNF-α expression and JNK phospholytion levels in the livers from fetal age to adulthood. Elevated JNK phospholytion could be linked to downregulated hepatocyte nuclear factor-4α and CYP7A1 expression, subsequently led to higher hepatic cholesterol. This work demonstrated that intrauterine malnutrition-induced IUGR might result in intrinsic disorder in hepatic TNF-α/CYP7A1 signaling, and contribute to the development of hypercholesterolemia in later life.

  12. KAP1 Is a Host Restriction Factor That Promotes Human Adenovirus E1B-55K SUMO Modification

    DEFF Research Database (Denmark)

    Bürck, Carolin; Mund, Andreas; Berscheminski, Julia

    2016-01-01

    and cellular SWI/SNF chromatin remodeling play a key role in HAdV transcriptional regulation (1-4). We observed that the cellular chromatin-associated factor, and epigenetic reader SPOC1 represses HAdV infection and gene expression. Here, we illustrate the role of the SPOC1 interacting factor KAP1 during...

  13. Expression of growth differentiation factor 6 in the human developing fetal spine retreats from vertebral ossifying regions and is restricted to cartilaginous tissues.

    Science.gov (United States)

    Wei, Aiqun; Shen, Bojiang; Williams, Lisa A; Bhargav, Divya; Gulati, Twishi; Fang, Zhimin; Pathmanandavel, Sarennya; Diwan, Ashish D

    2016-02-01

    During embryogenesis vertebral segmentation is initiated by sclerotomal cell migration and condensation around the notochord, forming anlagen of vertebral bodies and intervertebral discs. The factors that govern the segmentation are not clear. Previous research demonstrated that mutations in growth differentiation factor 6 resulted in congenital vertebral fusion, suggesting this factor plays a role in development of vertebral column. In this study, we detected expression and localization of growth differentiation factor 6 in human fetal spinal column, especially in the period of early ossification of vertebrae and the developing intervertebral discs. The extracellular matrix proteins were also examined. Results showed that high levels of growth differentiation factor 6 were expressed in the nucleus pulposus of intervertebral discs and the hypertrophic chondrocytes adjacent to the ossification centre in vertebral bodies, where strong expression of proteoglycan and collagens was also detected. As fetal age increased, the expression of growth differentiation factor 6 was decreased correspondingly with the progress of ossification in vertebral bodies and restricted to cartilaginous regions. This expression pattern and the genetic link to vertebral fusion suggest that growth differentiation factor 6 may play an important role in suppression of ossification to ensure proper vertebral segmentation during spinal development.

  14. Relationship between fetal growth restriction and angiogenesis factors%胎儿生长受限与血管生成因子的关系

    Institute of Scientific and Technical Information of China (English)

    黄赟博; 刘倩倩; 余艳红

    2014-01-01

    Placenta is an important organ to maintain fetal growth, metabolism, maternal and fetal physiologic balance. Angiogenesis is a critical factor in placental development involved in fetal blood circulation and vascular changes in the endometrium and placenta. Angiogenesis is closely related to angiogenesis factors such as vascular endothelial growth factor and placenta growth factor. Fetal growth restriction threats the fetal health in gestation and also increases the long-term likeliness of several diseases. In this review, the authors summarize the findings in current studies of the relationship between angiogenesis factors and fetal growth restriction.%胎盘是胎儿生长发育、代谢循环及维持母胎生理平衡的重要脏器。血管形成是胎盘发育的关键,其不仅包括胎儿血液循环,还包括子宫内膜和胎盘的血管变化。血管的形成与血管生成因子如血管内皮生长因子(VEGF)、胎盘生长因子(PLGF)等密切相关。胎儿生长受限(FGR)属严重高危妊娠,不仅对胎儿在妊娠期的健康造成威胁,还会增加分娩后远期多种疾病的发病率。目前已有关于血管生成因子与胎儿生长受限之间的研究,现将两者之间的关系作一综述。

  15. Early Life Stress and Sleep Restriction as Risk Factors in PTSD: An Integrative Pre-Clinical Approach

    Science.gov (United States)

    2014-04-01

    that CCK increases glutamatergic transmission in the DG (Sinton, 1988; Gabriel et al., 1996; Deng et al., 2010) as well as long-term potentiation (LTP...patterns of selected GABAergic and Glutamatergic factors in the ventral and dorsal hippocampus and in the BLA One-way ANOVA followed by post hoc...Table 2: Effects of an Exposure to Juvenile Stress, UWT and UWT reminder. Protein expression of GABAergic and glutamatergic factors was assessed in the

  16. 制约建筑节能推进的因素探究%Exploring the Restrictive Factors to Promote the Construction of Energy-efficient

    Institute of Scientific and Technical Information of China (English)

    2013-01-01

    With the rapid development of the global economy, building problems especial y the energy consumption problem becomes more and more significant, and actively promoted the urgent task of energy-saving construction work. This paper thr-ough the analysis of the significance of energy-saving constru-ction work, analyzes the restricting factors to promote the con-struction of energy-saving, aims to break the restriction factor to promote the construction of energy-saving in China, to acce-lerate the construction of energy-saving, let building energy ef-ficiency become the people's livelihood project which benefit the nation and people.%  随着全球经济的快速发展,建筑带来的问题特别是能源消耗问题越来越显著,积极推进建筑节能工作任务紧迫。本文通过分析建筑节能工作的意义,剖析制约我国建筑节能推进的因素,旨在破除我国建筑节能推进的制约因素,加快我国建筑节能的步伐,让建筑节能成为利国利民的民生工程。

  17. Effect of feed restriction and initial body weight on growth performance, body composition, and hormones in male pigs immunized against gonadotropin-releasing factor.

    Science.gov (United States)

    Moore, K L; Mullan, B P; Kim, J C; Payne, H G; Dunshea, F R

    2016-09-01

    Pigs immunized against gonadotropin-releasing factor (GnRF) have increased carcass fatness compared to entire males; however, the timing of this increase in fatness after the second immunization against GnRF has not been determined. An experiment was conducted to identify and compare the growth performance, body composition, and physiological changes in immunocastrated males (IC males) at different BW and feeding levels. A total of 64 pigs were used in a 2 × 2 × 2 factorial experiment with the treatments being 1) sex (entire males or IC males), 2) initial BW (45.9 kg [light] or 78.3 kg [heavy]), and 3) feeding regime (2.5 times maintenance [restricted] or ad libitum). The pigs were individually housed, and the diets were fed for 4 wk after the second immunization against GnRF until slaughter at either 68.4 kg BW (light) or 105.8 kg BW (heavy). Immunocastrated males on a restricted feed intake had a lower ADG compared to entire males from d 15 to 28 and d 0 to 28 ( 0.011 and 0.011, respectively). Fat deposition was not affected by sex from d 0 to 14, but from d 15 to 28 IC males deposited 45 g/d more fat than entire males ( = 0.025). Immunocastrated male pigs fed ad libitum deposited 87 g/d more fat from d 15 to 28 than entire males fed ad libitum ( = 0.036). However, there was no difference in fat deposition between IC males and entire males when feed intake was restricted from d 15 to 28. Plasma urea nitrogen levels were greater in IC males compared to entire males from d 7 after the second immunization against GnRF ( 0.05 for d 7, 10, 14, 21, and 28). Plasma concentrations of IGF-1 were lower for IC males compared to entire males on d 3, 7, 10, and 28 ( 0.05 for all days). The following conclusions were made: 1) when pigs are immunized at a light BW (50 kg) and/or are on a restricted feed intake, they have a reduced propensity to deposit fat; however, the restriction in feed intake adversely affects growth rate. 2) The majority of fat deposition for males

  18. A genome-wide screen for spatially restricted expression patterns identifies transcription factors that regulate glial development

    NARCIS (Netherlands)

    Fu, H.; Cai, J.; Clevers, H.; Fast, E.; Gray, S.; Greenberg, R.; Jain, M.K.; Ma, Q.; Qiu, M.; Rowitch, D.H.; Taylor, C.; Stiles, C.D.

    2009-01-01

    Forward genetic screens in genetically accessible invertebrate organisms such as Drosophila melanogaster have shed light on transcription factors that specify formation of neurons in the vertebrate CNS. However, invertebrate models have, to date, been uninformative with respect to genes that specify

  19. The Primary Resistance of Helicobacter pylori in Taiwan after the National Policy to Restrict Antibiotic Consumption and Its Relation to Virulence Factors-A Nationwide Study.

    Directory of Open Access Journals (Sweden)

    Jyh-Ming Liou

    Full Text Available The Taiwan Government issued a policy to restrict antimicrobial usage since 2001. We aimed to assess the changes in the antibiotic consumption and the primary resistance of H. pylori after this policy and the impact of virulence factors on resistance.The defined daily dose (DDD of antibiotics was analyzed using the Taiwan National Health Insurance (NHI research database. H. pylori strains isolated from treatment naïve (N=1395 and failure from prior eradication therapies (N=360 from 9 hospitals between 2000 and 2012 were used for analysis. The minimum inhibitory concentration was determined by agar dilution test. Genotyping for CagA and VacA was determined by PCR method.The DDD per 1000 persons per day of macrolides reduced from 1.12 in 1997 to 0.19 in 2008, whereas that of fluoroquinolones increased from 0.12 in 1997 to 0.35 in 2008. The primary resistance of amoxicillin, clarithromycin, metronidazole, and tetracycline remained as low as 2.2%, 7.9%, 23.7%, and 1.9% respectively. However, the primary levofloxacin resistance rose from 4.9% in 2000-2007 to 8.3% in 2008-2010 and 13.4% in 2011-2012 (p=0.001. The primary resistance of metronidazole was higher in females than males (33.1% vs. 18.8%, p<0.001, which was probably attributed to the higher consumption of nitroimidazole. Neither CagA nor VacA was associated with antibiotic resistance.The low primary clarithromycin and metronidazole resistance of H. pylori in Taiwan might be attributed to the reduced consumption of macrolides and nitroimidazole after the national policy to restrict antimicrobial usage. Yet, further strategies are needed to restrict the consumption of fluoroquinolones in the face of rising levofloxacin resistance.

  20. Fetal growth restriction and the programming of heart growth and cardiac insulin-like growth factor 2 expression in the lamb

    Science.gov (United States)

    Wang, Kimberley C W; Zhang, Lei; McMillen, I Caroline; Botting, Kimberley J; Duffield, Jaime A; Zhang, Song; Suter, Catherine M; Brooks, Doug A; Morrison, Janna L

    2011-01-01

    Abstract Reduced growth in fetal life together with accelerated growth in childhood, results in a ∼50% greater risk of coronary heart disease in adult life. It is unclear why changes in patterns of body and heart growth in early life can lead to an increased risk of cardiovascular disease in adulthood. We aimed to investigate the role of the insulin-like growth factors in heart growth in the growth-restricted fetus and lamb. Hearts were collected from control and placentally restricted (PR) fetuses at 137–144 days gestation and from average (ABW) and low (LBW) birth weight lambs at 21 days of age. We quantified cardiac mRNA expression of IGF-1, IGF-2 and their receptors, IGF-1R and IGF-2R, using real-time RT-PCR and protein expression of IGF-1R and IGF-2R using Western blotting. Combined bisulphite restriction analysis was used to assess DNA methylation in the differentially methylated region (DMR) of the IGF-2/H19 locus and of the IGF-2R gene. In PR fetal sheep, IGF-2, IGF-1R and IGF-2R mRNA expression was increased in the heart compared to controls. LBW lambs had a greater left ventricle weight relative to body weight as well as increased IGF-2 and IGF-2R mRNA expression in the heart, when compared to ABW lambs. No changes in the percentage of methylation of the DMRs of IGF-2/H19 or IGF-2R were found between PR and LBW when compared to their respective controls. In conclusion, a programmed increased in cardiac gene expression of IGF-2 and IGF-2R may represent an adaptive response to reduced substrate supply (e.g. glucose and/or oxygen) in order to maintain heart growth and may be the underlying cause for increased ventricular hypertrophy and the associated susceptibility of cardiomyocytes to ischaemic damage later in life. PMID:21807611

  1. Energy restriction and exercise modulate angiopoietins and vascular endothelial growth factor expression in the cavernous tissue of high-fat diet-fed rats

    Institute of Scientific and Technical Information of China (English)

    In(ě)s Tomada; Nuno Tomada; Henrique Almeida; Delminda Neves

    2012-01-01

    The purpose of the current study was to evaluate the effect of a high-fat (HF) diet,energy restriction and exercise on the expression of vascular endothelial growth factor (VEGF),angiopoietin (Ang) 1 and 2,and their receptors in rat corpus cavernosum (CC).Male Wistar rats were fed adlibitum with an HF diet for 8 or 16 weeks.After 8 weeks of the HF diet,a group of rats was subjected to energy restriction with or without exercise for 8 weeks.Control animals had free access to standard diet for the same period.After euthanasia,blood was collected and the penises removed for immunofluorescence assays (VEGF,VEGF receptor (VEGFR) 1 and 2,Ang1,Ang2 and Tie2) and semiquantification of VEGF,VEGFR1,VEGFR2,Ang1,Ang2,Tie2,endothelial nitric oxide synthase (eNOS) and Akt/phospho-Akt by Western blotting.HF diet-fed rats exhibited lower high-density lipoprotein cholesterol (HDL-c) levels,higher systolic blood pressure and an increased atherogenic index.A significant increase in Ang2 expression in the CC was verified and coupled to a decrease in VEGF and VEGFRs.The Akt pathway was activated by the HF diet.Energy restriction and exercise increased eNOS expression and restored most HF diet-induced modifications except for VEGFR2 expression.These results emphasize the role of diet on vascular function regulation,demonstrating that cavernous imbalance of VEGF/VEGFRs and Angs/rie2 systems occurs before serum lipid changes and obesity onset,antedating structural atherosclerotic features.

  2. The critical role of personality and organizational factors as determinants of reactions to restricted and stressful environments. [undersea habitats

    Science.gov (United States)

    Helmreich, Robert L.

    1987-01-01

    Research into the impact of personality factors on groups in various settings is reviewed as an introduction to a brief discussion of personality and group behavior research needs relevant to the space program. Significant findings of some earlier research are summarized, and methodological problems are touched on. The study of intergroup and intragroup conflict in a stressful environment, as exemplified particularly by undersea habitats, is seen as being of consequence for long-term space missions. It is concluded that adequate research can only be conducted as an adjunct to data collection from operational stressful environments, and not from laboratory experiments.

  3. A novel lineage transcription factor based analysis reveals differences in T helper cell subpopulation development in infected and intrauterine growth restricted (IUGR) piglets.

    Science.gov (United States)

    Ebner, F; Rausch, S; Scharek-Tedin, L; Pieper, R; Burwinkel, M; Zentek, J; Hartmann, S

    2014-10-01

    Research in mouse and human clearly identified subsets of T helper (Th) cells based on nuclear expression of specific lineage transcription factors. In swine, however, transcription factor based detection of functional subpopulations of porcine Th cells by flow cytometry is so far limited to regulatory T cells via Foxp3. T-bet and GATA-3 are the transcription factors that regulate commitment to Th1 or Th2 cells, respectively. In this study we prove GATA-3 and T-bet expression in porcine CD4(+) cells polarized in vitro. Importantly, GATA-3 and T-bet expressing cells were detectable in pigs infected with pathogens associated with Th2 and Th1 immune responses. Increased frequencies of GATA-3 positive CD4(+) cells are found in vivo in pigs experimentally infected with the nematode Trichuris suis, whereas porcine reproductive and respiratory syndrome virus (PRRSV) infection elicited T-bet positive CD4(+) T cells. Analysing the immune status of pre-weaning piglets with intrauterine growth restriction (IUGR) we found an increased expression of Foxp3, T-bet and GATA-3 in CD4(+) and CD4(+)CD8(+) double-positive T cells in systemic and intestinal compartments of IUGR piglets. Hence, we established the detection of porcine Th1 and Th2 cells via T-bet and GATA-3 and show that the porcine lineage transcription factors are differentially regulated very early in life depending on the developmental status.

  4. The immune adaptor molecule SARM modulates tumor necrosis factor alpha production and microglia activation in the brainstem and restricts West Nile Virus pathogenesis.

    Science.gov (United States)

    Szretter, Kristy J; Samuel, Melanie A; Gilfillan, Susan; Fuchs, Anja; Colonna, Marco; Diamond, Michael S

    2009-09-01

    Sterile alpha and HEAT/Armadillo motif (SARM) is a highly conserved Toll/interleukin-1 receptor (TIR)-containing adaptor protein that is believed to negatively regulate signaling of the pathogen recognition receptors Toll-like receptor 3 (TLR3) and TLR4. To test its physiological function in the context of a microbial infection, we generated SARM(-/-) mice and evaluated the impact of this deficiency on the pathogenesis of West Nile virus (WNV), a neurotropic flavivirus that requires TLR signaling to restrict infection. Although SARM was preferentially expressed in cells of the central nervous system (CNS), studies with primary macrophages, neurons, or astrocytes showed no difference in viral growth kinetics. In contrast, viral replication was increased specifically in the brainstem of SARM(-/-) mice, and this was associated with enhanced mortality after inoculation with a virulent WNV strain. A deficiency of SARM was also linked to reduced levels of tumor necrosis factor alpha (TNF-alpha), decreased microglia activation, and increased neuronal death in the brainstem after WNV infection. Thus, SARM appears to be unique among the TIR adaptor molecules, since it functions to restrict viral infection and neuronal injury in a brain region-specific manner, possibly by modulating the activation of resident CNS inflammatory cells.

  5. Elongation factor P restricts Salmonella’s growth by controlling translation of a Mg2+ transporter gene during infection

    Science.gov (United States)

    Choi, Eunna; Choi, Soomin; Nam, Daesil; Park, Shinae; Han, Yoontak; Lee, Jung-Shin; Lee, Eun-Jin

    2017-01-01

    When a ribosome translates mRNA sequences, the ribosome often stalls at certain codons because it is hard to translate. Consecutive proline codons are such examples that induce ribosome stalling and elongation factor P (EF-P) is required for the stalled ribosome to continue translation at those consecutive proline codons. We found that EF-P is required for translation of the mgtB gene encoding a Mg2+ transporter in the mgtCBR virulence operon from the intracellular pathogen Salmonella enterica serovar Typhimurium. Salmonella lacking EF-P decreases MgtB protein levels in a manner dependent on consecutive proline codons located in the mgtB coding region despite increasing transcription of the mgtCBR operon via the mgtP open reading frame in the leader RNA, resulting in an altered ratio between MgtC and MgtB proteins within the operon. Substitution of the consecutive proline codons to alanine codons eliminates EF-P-mediated control of the mgtB gene during infection and thus contributes to Salmonella’s survival inside macrophages where Salmonella experiences low levels of EF-P. This suggests that this pathogen utilizes a strategy to coordinate expression of virulence genes by an evolutionarily conserved translation factor. PMID:28181542

  6. Hepatic insulin-like growth-factor binding protein (igfbp) responses tofood restriction in Atlantic salmon smolts

    Science.gov (United States)

    Breves, Jason P.; Phipps-Costin, Silas K.; Fujimoto, Chelsea K.; Einarsdottir, Ingibjörg E.; Regish, Amy M.; Björnsson, Björn Thrandur; McCormick, Stephen

    2016-01-01

    The growth hormone (Gh)/insulin-like growth-factor (Igf) system plays a central role in the regulation of growth in fishes. However, the roles of Igf binding proteins (Igfbps) in coordinating responses to food availability are unresolved, especially in anadromous fishes preparing for seaward migration. We assayed plasma Gh, Igf1, thyroid hormones and cortisol along with igfbp mRNA levels in fasted and fed Atlantic salmon ( Salmo salar ). Fish were fasted for 3 or 10 days near the peak of smoltification (late April to early May). Fasting reduced plasma glucose by 3 days and condition factor by 10 days. Plasma Gh, cortisol, and thyroxine (T 4 ) were not altered in response to fasting, whereas Igf1 and 3,5,3′-triiodo- l -thyronine (T 3 ) were slightly higher and lower than controls, respectively. Hepatic igfbp1b1 , - 1b2 , - 2a , - 2b1 and - 2b2 mRNA levels were not responsive to fasting, but there were marked increases in igfbp1a1 following 3 and 10 days of fasting. Fasting did not alter hepatic igf1or igf2 ; however, muscle igf1 was diminished by 10 days of fasting. There were no signs that fasting compromised branchial ionoregulatory functions, as indicated by unchanged Na + /K + -ATPase activity and ion pump/transporter mRNA levels. We conclude that dynamic hepatic igfbp1a1 and muscle igf1 expression participate in the modulation of Gh/Igf signaling in smolts undergoing catabolism.

  7. Formation of the embryonic organizer is restricted by the competitive influences of Fgf signaling and the SoxB1 transcription factors.

    Directory of Open Access Journals (Sweden)

    Cheng-Liang Kuo

    Full Text Available The organizer is one of the earliest structures to be established during vertebrate development and is crucial to subsequent patterning of the embryo. We have previously shown that the SoxB1 transcription factor, Sox3, plays a central role as a transcriptional repressor of zebrafish organizer gene expression. Recent data suggest that Fgf signaling has a positive influence on organizer formation, but its role remains to be fully elucidated. In order to better understand how Fgf signaling fits into the complex regulatory network that determines when and where the organizer forms, the relationship between the positive effects of Fgf signaling and the repressive effects of the SoxB1 factors must be resolved. This study demonstrates that both fgf3 and fgf8 are required for expression of the organizer genes, gsc and chd, and that SoxB1 factors (Sox3, and the zebrafish specific factors, Sox19a and Sox19b can repress the expression of both fgf3 and fgf8. However, we also find that these SoxB1 factors inhibit the expression of gsc and chd independently of their repression of fgf expression. We show that ectopic expression of organizer genes induced solely by the inhibition of SoxB1 function is dependent upon the activation of fgf expression. These data allow us to describe a comprehensive signaling network in which the SoxB1 factors restrict organizer formation by inhibiting Fgf, Nodal and Wnt signaling, as well as independently repressing the targets of that signaling. The organizer therefore forms only where Nodal-induced Fgf signaling overlaps with Wnt signaling and the SoxB1 proteins are absent.

  8. Calorie restriction and stroke

    Directory of Open Access Journals (Sweden)

    Manzanero Silvia

    2011-09-01

    Full Text Available Abstract Stroke, a major cause of disability and mortality in the elderly, occurs when a cerebral blood vessel is occluded or ruptured, resulting in ischemic damage and death of brain cells. The injury mechanism involves metabolic and oxidative stress, excitotoxicity, apoptosis and inflammatory processes, including activation of glial cells and infiltration of leukocytes. In animal models, dietary energy restriction, by daily calorie reduction (CR or intermittent fasting (IF, extends lifespan and decreases the development of age-related diseases. Dietary energy restriction may also benefit neurons, as suggested by experimental evidence showing that CR and IF protect neurons against degeneration in animal models. Recent findings by our group and others suggest the possibility that dietary energy restriction may protect against stroke induced brain injury, in part by inducing the expression of neurotrophic factors, such as brain-derived neurotrophic factor (BDNF and basic fibroblast growth factor (bFGF; protein chaperones, including heat shock protein 70 (Hsp70 and glucose regulated protein 78 (GRP78; antioxidant enzymes, such as superoxide dismutases (SOD and heme oxygenase-1 (HO-1, silent information regulator T1 (SIRT1, uncoupling proteins and anti-inflammatory cytokines. This article discusses the protective mechanisms activated by dietary energy restriction in ischemic stroke.

  9. HIV-1 Vif, APOBEC, and Intrinsic Immunity

    Directory of Open Access Journals (Sweden)

    Strebel Klaus

    2008-06-01

    Full Text Available Abstract Members of the APOBEC family of cellular cytidine deaminases represent a recently identified group of proteins that provide immunity to infection by retroviruses and protect the cell from endogenous mobile retroelements. Yet, HIV-1 is largely immune to the intrinsic antiviral effects of APOBEC proteins because it encodes Vif (viral infectivity factor, an accessory protein that is critical for in vivo replication of HIV-1. In the absence of Vif, APOBEC proteins are encapsidated by budding virus particles and either cause extensive cytidine to uridine editing of negative sense single-stranded DNA during reverse transcription or restrict virus replication through deaminase-independent mechanisms. Thus, the primary function of Vif is to prevent encapsidation of APOBEC proteins into viral particles. This is in part accomplished by the ability of Vif to induce the ubiquitin-dependent degradation of some of the APOBEC proteins. However, Vif is also able to prevent encapsidation of APOBEC3G and APOBEC3F through degradation-independent mechanism(s. The goal of this review is to recapitulate current knowledge of the functional interaction of HIV-1 and its Vif protein with the APOBEC3 subfamily of proteins and to summarize our present understanding of the mechanism of APOBEC3-dependent retrovirus restriction.

  10. RE1 silencing transcription factor/neuron-restrictive silencing factor regulates expansion of adult mouse subventricular zone-derived neural stem/progenitor cells in vitro.

    Science.gov (United States)

    Soldati, Chiara; Caramanica, Pasquale; Burney, Matthew J; Toselli, Camilla; Bithell, Angela; Augusti-Tocco, Gabriella; Stanton, Lawrence W; Biagioni, Stefano; Buckley, Noel J; Cacci, Emanuele

    2015-08-01

    Adult neural stem cell (aNSC) activity is tuned by external stimuli through the recruitment of transcription factors. This study examines the RE1 silencing transcription factor (REST) in neural stem/progenitor cells isolated from the subventricular zone of adult mouse brain and provides the first extensive characterization of REST-mediated control of the cellular and molecular properties. This study shows that REST knockdown affects the capacity of progenitor cells to generate neurospheres, reduces cell proliferation, and triggers cell differentiation despite the presence of growth factors. Genome- and transcriptome-wide analyses show that REST binding sites are significantly enriched in genes associated with synaptic transmission and nervous system development and function. Seeking candidate regulators of aNSC function, this study identifies a member of the bone morphogenetic protein (BMP) family, BMP6, the mRNA and protein of which increased after REST knockdown. The results of this study extend previous findings, demonstrating a reciprocal control of REST expression by BMPs. Administration of exogenous BMP6 inhibits aNSC proliferation and induces the expression of the astrocytic marker glial fibrillary acidic protein, highlighting its antimitogenic and prodifferentiative effects. This study suggests that BMP6 produced in a REST-regulated manner together with other signals can contribute to regulation of NSC maintenance and fate.

  11. Interferon regulatory factor-two restricts expression of interferon-stimulated genes to the endometrial stroma and glandular epithelium of the ovine uterus.

    Science.gov (United States)

    Choi, Y; Johnson, G A; Burghardt, R C; Berghman, L R; Joyce, M M; Taylor, K M; Stewart, M D; Bazer, F W; Spencer, T E

    2001-10-01

    Interferon tau (IFNtau) is the signal for maternal recognition of pregnancy in ruminants. The positive effects of IFNtau on IFN-stimulated gene (ISG) expression are mediated by ISG factor 3 (ISGF3), which is composed of signal transducer and activator of transcription (Stat) 1, Stat 2, and IFN regulatory factor-9 (IRF-9), and by gamma-activated factor (GAF), which is a Stat 1 homodimer. Induction of ISGs, such as ISG17 and 2',5'-oligoadenylate synthetase, by IFNtau during pregnancy is limited to the endometrial stroma (S) and glandular epithelium (GE) of the ovine uterus. The IRF-2, a potent transcriptional repressor of ISG expression, is expressed in the luminal epithelium (LE). This study determined effects of the estrous cycle, pregnancy, and IFNtau on expression of Stat 1, Stat 2, IRF-9, IRF-1, and IRF-2 genes in the ovine endometrium. In cyclic ewes, Stat 1, Stat 2, IRF-1, and IRF-9 mRNA and protein were detected at low levels in the S and GE. During pregnancy, expression of these genes increased only in the S and GE. Expression of IRF-2 was detected only in the LE and superficial GE (sGE) of both cyclic and pregnant ewes. In cyclic ewes, intrauterine administration of IFNtau stimulated Stat 1, Stat 2, IRF-9, and IRF-1 expression in the endometrium. Ovine IRF-2 repressed transcriptional activity driven by IFN-stimulated response elements that bind ISGF3, but not by gamma-activation sequences that bind GAF. These results suggest that IRF-2 in the LE and sGE restricts IFNtau induction of ISGs to the S and GE. In the S and GE, IFNtau hyperactivation of ISG expression likely involves formation and actions of the transcription factors ISGF3 and, perhaps, IRF-1.

  12. Anti-oxidative and anti-inflammatory vasoprotective effects of caloric restriction in aging: role of circulating factors and SIRT1.

    Science.gov (United States)

    Csiszar, Anna; Labinskyy, Nazar; Jimenez, Rosario; Pinto, John T; Ballabh, Praveen; Losonczy, Gyorgy; Pearson, Kevin J; de Cabo, Rafael; Ungvari, Zoltan

    2009-08-01

    Endothelial dysfunction, oxidative stress and inflammation are associated with vascular aging and promote the development of cardiovascular disease. Caloric restriction (CR) mitigates conditions associated with aging, but its effects on vascular dysfunction during aging remain poorly defined. To determine whether CR exerts vasoprotective effects in aging, aortas of ad libitum (AL) fed young and aged and CR-aged F344 rats were compared. Aging in AL-rats was associated with impaired acetylcholine-induced relaxation, vascular oxidative stress and increased NF-kappaB activity. Lifelong CR significantly improved endothelial function, attenuated vascular ROS production, inhibited NF-kappaB activity and down-regulated inflammatory genes. To elucidate the role of circulating factors in mediation of the vasoprotective effects of CR, we determined whether sera obtained from CR animals can confer anti-oxidant and anti-inflammatory effects in cultured coronary arterial endothelial cells (CAECs), mimicking the effects of CR. In CAECs cultured in the presence of AL serum TNFalpha elicited oxidative stress, NF-kappaB activation and inflammatory gene expression. By contrast, treatment of CAECs with CR serum attenuated TNFalpha-induced ROS generation and prevented NF-kappaB activation and induction of inflammatory genes. siRNA knockdown of SIRT1 mitigated the anti-oxidant and anti-inflammatory effects of CR serum. CR exerts anti-oxidant and anti-inflammatory vascular effects, which are likely mediated by circulating factors, in part, via a SIRT1-dependent pathway.

  13. Pineal gland expression of the transcription factor Egr-1 is restricted to a population of glia that are distinct from nestin-immunoreactive cells.

    Science.gov (United States)

    Man, Pui-Sin; Carter, David A

    2008-02-01

    Egr-1 is a plasticity-related transcription factor that has been implicated in circadian regulation of the pineal gland. In the present study we have investigated the cellular expression pattern of Egr-1 in the adult rat pineal. Egr-1 protein is restricted to the nucleus of a sub-population of cells. These cells were characterised using a new transgenic rat model (egr-1-d2EGFP) in which green fluorescent protein is driven by the egr-1 promoter. Cellular filling by GFP revealed that Egr-1-positive cells exhibited processes, indicating a glial cell-type morphology. This was confirmed by co-localizing the GFP-filled processes with vimentin and S-100beta. However, GFP/Egr-1 is expressed in only a tiny minority of the previously identified Id-1/vimentin-positive glial cells and therefore represents a novel sub-set of this (GFAP-negative) glial population. We have also demonstrated for the first time an extensive network of nestin-positive cells throughout the adult pineal gland, however these cells do not co-express Egr-1. Our studies have therefore broadened our understanding of the cell populations that constitute the adult pineal. Cellular localization of Egr-1 has revealed that this factor does not appear to be directly involved in pinealocyte production of melatonin but is required in a sub-set of pineal glia.

  14. Cyclin F/FBXO1 interacts with HIV-1 Vif and restricts progeny virion infectivity by ubiquitination and proteasomal degradation of Vif through SCF (Cyclin F) E3 ligase machinery.

    Science.gov (United States)

    Augustine, Tracy; Chaudhary, Priyanka; Gupta, Kailash; Islam, Sehbanul; Ghosh, Payel; Santra, Manas Kumar; Mitra, Debashis

    2017-02-09

    Cyclin F, also known as FBXO1, is the largest among all cyclins which oscillates in the cell cycle like other cyclins. Apart from being a G2/M cyclin, Cyclin F functions as the substrate binding subunit of SCFCyclin F E3 ubiquitin ligase. In a gene expression analysis performed to identify novel gene modulations associated with cell cycle dysregulation during HIV-1 infection in CD4+ T cells, we observed down-regulation of Cyclin F (CCNF) gene. Later, using gene over expression and knockdown studies, we identified that Cyclin F negatively influences HIV-1 viral infectivity without any significant impact on virus production. Subsequently, we found that Cyclin F negatively regulates the expression of viral protein, Vif (Viral infectivity factor), at the protein level. We also identified a novel host-pathogen interaction between Cyclin F and Vif protein in T cells during HIV-1 infection. Mutational analysis of a Cyclin F-specific amino acid motif in the C-terminal region of Vif shows rescue of the protein from Cyclin F-mediated down-regulation. Subsequently, we have shown that Vif is a novel substrate of the SCFCyclin F E3 ligase, where Cyclin F mediates ubiquitination and proteasomal degradation of Vif through physical interaction. Finally, we have shown that Cyclin F augments APOBEC3G expression through degradation of Vif to regulate infectivity of progeny virions. Taken together, our results demonstrate Cyclin F as a novel F-box protein which functions as an intrinsic cellular regulator of HIV-1 Vif and imparts a negative regulatory effect on maintenance of viral infectivity by restoring APOBEC3G expression.

  15. Evaluation of udder health parameters and risk factors for clinical mastitis in Dutch dairy herds in the context of a restricted antimicrobial usage policy.

    Science.gov (United States)

    Santman-Berends, I M G A; Swinkels, J M; Lam, T J G M; Keurentjes, J; van Schaik, G

    2016-04-01

    study indicated that udder health had not deteriorated compared with udder health in previous Dutch studies where herd sizes were somewhat smaller and before the restrictions in antimicrobial use. Several of the risk factors that were found can be influenced by the farmer and can prevent the occurrence of CMI. Still, when cases of CM occur, treatment with antimicrobials might be necessary to cure the CM case and is beneficial for the overall udder health in the herd.

  16. 制约辽宁省居民消费能力提升的因素%Restrictive Factors To Enhance Consumption Capacity Of Liaoning Province Residents

    Institute of Scientific and Technical Information of China (English)

    姜羽西

    2015-01-01

    Insufficient household consumption has become a great obstacle to develop economy.It also profoundly affects the coordinated development of investment,consumption and export.The overall consumption ability of liaoning province residents is insufficient.According to analysis,we suggest that unreasonable resident income distribution,lower consumption concept,lower expectation of social security in the future and imperfect consumption environment become restrictive factors to enhance ability of residents'consumption in liaoning and then we put forward countermeasures and suggestions.Finally we hope realize the new pattern of consumption,investment and export to drive economic growth.%居民消费不足已成为经济发展的巨大障碍,也影响着投资、消费、出口的协调发展. 辽宁省居民的总体消费能力不足,通过分析得出,居民收入分配不合理、消费理念偏低、未来保障预期低以及消费环境不完善等都成为制约辽宁居民消费能力提升的因素,据此提出对策建议,最终实现消费、投资、出口协同驱动经济增长的新格局.

  17. Development of a polymerase chain reaction-restriction fragment length polymorphism method for identification of the Fusarium genus using the transcription elongation factor-1α gene.

    Science.gov (United States)

    Zarrin, Majid; Ganj, Farzaneh; Faramarzi, Sama

    2016-12-01

    Fusarium species are well-known plant pathogens and food contaminants that have also appeared as one of the most important groups of medically significant fungi. The sequences of the translation elongation factor (TEF)-1α gene have been broadly employed for species detection. A total of 50 strains of Fusarium spp., including environmental, clinical and reference isolates were used for the current study. The primer sets, Fu3f and Fu3r, were used to amplify an ~420-bp DNA fragment of the TEF-1α gene. Double digestion with two restriction enzymes, XhoI and SduI was used for discrimination of the Fusarium species in the TEF-1α gene fragment. Double digestion of the TEF-1α gene fragment from five clinically important Fusarium species were clearly differentiated from each other: The F. solani species complex, F. oxysporum species complex, F. verticillioides, F. proliferatum and F. fujikuroi. This method facilitates detection and enables verification of the Fusarium genus; therefore, it may be applied for disease control.

  18. The effects of the calcium-restricted diet of urolithiasis patients with absorptive hypercalciuria type II on risk factors for kidney stones and osteopenia

    NARCIS (Netherlands)

    Faassen, A. van; Ploeg, E.M.C. van der; Habets, H.M.L.; Meer, R. van der; Hermus, R.J.J.; Janknegt, R.A.

    1998-01-01

    The calcium (Ca)-restricted diet of urolithiasis patients with absorptive hypercalciuria type II may decrease Ca excretion but increase biochemical markers of risk for osteopenia. We randomly allocated 25 patients from six hospitals into an experimental group (Ca restriction to 500 mg/day, oxalate-r

  19. Defining HIV-1 Vif residues that interact with CBFβ by site-directed mutagenesis.

    Science.gov (United States)

    Matsui, Yusuke; Shindo, Keisuke; Nagata, Kayoko; Io, Katsuhiro; Tada, Kohei; Iwai, Fumie; Kobayashi, Masayuki; Kadowaki, Norimitsu; Harris, Reuben S; Takaori-Kondo, Akifumi

    2014-01-20

    Vif is essential for HIV-1 replication in T cells and macrophages. Vif recruits a host ubiquitin ligase complex to promote proteasomal degradation of the APOBEC3 restriction factors by poly-ubiquitination. The cellular transcription cofactor CBFβ is required for Vif function by stabilizing the Vif protein and promoting recruitment of a cellular Cullin5-RING ubiquitin ligase complex. Interaction between Vif and CBFβ is a promising therapeutic target, but little is known about the interfacial residues. We now demonstrate that Vif conserved residues E88/W89 are crucial for CBFβ binding. Substitution of E88/W89 to alanines impaired binding to CBFβ, degradation of APOBEC3, and virus infectivity in the presence of APOBEC3 in single-cycle infection. In spreading infection, NL4-3 with Vif E88A/W89A mutation replicated comparably to wild-type virus in permissive CEM-SS cells, but not in multiple APOBEC3 expressing non-permissive CEM cells. These results support a model in which HIV-1 Vif residues E88/W89 may participate in binding CBFβ.

  20. Somatotropin as the non-ACTH factor of anterior pituitary origin for the maintenance of enhanced aldosterone secretory responsiveness of dietary sodium restriction in chronically hypophysectomized rats

    NARCIS (Netherlands)

    Lee, T.C.; Wied, D. de

    1968-01-01

    Somatotropin treatment in chronically hypophysectomized, sodium-deprived rats effectively restored to treated animals the distinct and enhanced aldosterone secretory responsiveness of the adrenal which characterizes the adrenals of intact rats subjected to dietary sodium restriction, but absent in c

  1. The Factors Restricting the Sustainable Development of the Borderland of Southwest China%西南边疆可持续发展制约因素研究

    Institute of Scientific and Technical Information of China (English)

    胡阳全

    2009-01-01

    Sustainable development is a must in the strategic choices of all countries and regions of the world. Facing the transitional period and quick development, the borderland of China should also stick to this choice. The borderland of southwest China occupies a strategically important position but has a quite a few factors restricting its sustainable development like the poor transportation system, relatively slow social and economic development and a worsening ecology. The solutions to these problems include the adherence to the concept of scientific development, the control of the population growth and the improvement of the population quality, the optimizing of the industrial structure, strengthen self-reliance, protect the ecology and deal well with all the relationships in the social development.%可持续发展是当今世界和各地区长期发展战略的必然选择,对我国正处在急剧转型期和加速发展的边疆,更应坚持这一发展战略选择.西南边疆是我国地缘战略位置极为重要的地区,又是交通不便、产业结构层次低、社会经济发展滞后、贫困面大、生态恶化加剧的地区.针对西南边疆可持续发展面临的制约因素,必须坚持科学发展观,控制人口过快增长和提高人口素质,调整优化产业结构,增强自我发展能力,保护生态环境,正确处理好社会发展中的各种关系.

  2. 学风建设的制约因素和对策研究%Research on restrictive factors and countermeasures of the study style construction

    Institute of Scientific and Technical Information of China (English)

    张婷婷

    2013-01-01

    学风问题在学校的生存和发展以及学生的成长成才过程中都处于重要的地位。影响和制约学风建设的因素主要有社会的、学校的、教师和学生本身的因素。靠完善的制度来规范学风建设,靠高尚的师德来引领学风建设,靠严格的管理来推进学风建设,靠榜样的示范作用带动学风建设,靠亲情的力量促进学风建设,是学风建设的有效对策和路径。%It is important problem of study style in the growth process of the survival and development of schools and students. Factors affecting and restricting the construction of study style are mainly social, school, teachers and students themselves. Relying on perfect system to regulate the construction of study style, by the noble morality to guide the construction of style of study, by strict management to promote the construction of style of study, an exemplary role model driven by the construction of study style, by the strength of family ties and promote the construction of study style, is the effective countermeasures and path of the construction of study style.

  3. Calorie restriction decreases murine and human pancreatic tumor cell growth, nuclear factor-κB activation, and inflammation-related gene expression in an insulin-like growth factor-1-dependent manner.

    Directory of Open Access Journals (Sweden)

    Alison E Harvey

    Full Text Available Calorie restriction (CR prevents obesity and has potent anticancer effects that may be mediated through its ability to reduce serum growth and inflammatory factors, particularly insulin-like growth factor (IGF-1 and protumorigenic cytokines. IGF-1 is a nutrient-responsive growth factor that activates the inflammatory regulator nuclear factor (NF-κB, which is linked to many types of cancers, including pancreatic cancer. We hypothesized that CR would inhibit pancreatic tumor growth through modulation of IGF-1-stimulated NF-κB activation and protumorigenic gene expression. To test this, 30 male C57BL/6 mice were randomized to either a control diet consumed ad libitum or a 30% CR diet administered in daily aliquots for 21 weeks, then were subcutaneously injected with syngeneic mouse pancreatic cancer cells (Panc02 and tumor growth was monitored for 5 weeks. Relative to controls, CR mice weighed less and had decreased serum IGF-1 levels and smaller tumors. Also, CR tumors demonstrated a 70% decrease in the expression of genes encoding the pro-inflammatory factors S100a9 and F4/80, and a 56% decrease in the macrophage chemoattractant, Ccl2. Similar CR effects on tumor growth and NF-κB-related gene expression were observed in a separate study of transplanted MiaPaCa-2 human pancreatic tumor cell growth in nude mice. In vitro analyses in Panc02 cells showed that IGF-1 treatment promoted NF-κB nuclear localization, increased DNA-binding of p65 and transcriptional activation, and increased expression of NF-κB downstream genes. Finally, the IGF-1-induced increase in expression of genes downstream of NF-κB (Ccdn1, Vegf, Birc5, and Ptgs2 was decreased significantly in the context of silenced p65. These findings suggest that the inhibitory effects of CR on Panc02 pancreatic tumor growth are associated with reduced IGF-1-dependent NF-κB activation.

  4. Interferon-alpha mediates restriction of human immunodeficiency virus type-1 replication in primary human macrophages at an early stage of replication.

    Directory of Open Access Journals (Sweden)

    Kelly M Cheney

    Full Text Available Type I interferons (IFNα and β are induced directly in response to viral infection, resulting in an antiviral state for the cell. In vitro studies have shown that IFNα is a potent inhibitor of viral replication; however, its role in HIV-1 infection is incompletely understood. In this study we describe the ability of IFNα to restrict HIV-1 infection in primary human macrophages in contrast to peripheral blood mononuclear cells and monocyte-derived dendritic cells. Inhibition to HIV-1 replication in cells pretreated with IFNα occurred at an early stage in the virus life cycle. Late viral events such as budding and subsequent rounds of infection were not affected by IFNα treatment. Analysis of early and late HIV-1 reverse transcripts and integrated proviral DNA confirmed an early post entry role for IFNα. First strand cDNA synthesis was slightly reduced but late and integrated products were severely depleted, suggesting that initiation or the nucleic acid intermediates of reverse transcription are targeted. The depletion of integrated provirus is disproportionally greater than that of viral cDNA synthesis suggesting the possibility of a least an additional later target. A role for either cellular protein APOBEC3G or tetherin in this IFNα mediated restriction has been excluded. Vpu, previously shown by others to rescue a viral budding restriction by tetherin, could not overcome this IFNα induced effect. Determining both the viral determinants and cellular proteins involved may lead to novel therapeutic approaches. Our results add to the understanding of HIV-1 restriction by IFNα.

  5. Logistic regression analysis on risk factors of fetal growth restriction%胎儿生长受限高危因素的Logistic回归分析

    Institute of Scientific and Technical Information of China (English)

    陈忠; 许建娟

    2012-01-01

    Objective: To explore the risk factors of fetal growth restriction (FGR) . Methods: A 1: 1 matched case - control study was conducted. The clinical data of 276 neonates with FGR (FGR group) and 276 neonates with normal weight (normal group) born in the hospital and the parturient women in 2011 were analyzed retrospectively. Results; There were statistically significant differences in maternal age, educational level, family monthly income, smoking, drinking tea, history of gestational infection, gestational complications, and fetal age of neonates between FGR group and normal group ( P < 0.05) . Taking neonatal weight as dependent variable, and taking the other factors as independent variables, non - conditional logistic regression analysis was conducted, the results showed that there were statistically significant differences in maternal age, educational level, family monthly income, smoking, drinking tea, history of gestational infection, gestational complications, and fetal age of neonates (P < 0.05) . Conclusion: High maternal age, low educational level, low family monthly income, smoking, drinking tea, history of gestational infection, gestational complications, and low fetal age of neonates are high risk factors of FGR. Active prevention targeting to the above - mentioned high risk factors during gestational period should be conducted to reduce the occurrence of FGR.%目的:探讨胎儿生长受限(FGR)发生的高危因素.方法:采用1∶1配比的病例对照研究设计,对2011年在该院分娩的276例FGR新生儿(FGR组)及276例正常体重新生儿(正常组)及其产妇病历资料进行回顾性分析.结果:FGR组与正常组在产妇年龄、文化程度、家庭月收入、吸烟、饮茶、妊娠期感染史、妊娠期合并症、妊娠期并发症、新生儿胎龄等单因素方面比较存在差异,差异有统计学意义(P<0.05);以新生儿体重为因变量,其他因素为自变量,进行非条件性的Logistic多因素分析,结果

  6. 我国扩大消费的制约因素及对策研究%Research on the restricting factors and countermeasures of expanding spending power

    Institute of Scientific and Technical Information of China (English)

    张磊

    2012-01-01

    随着经济社会的进一步发展,传统经济发展模式的弊端逐渐显露出来。要克服传统经济发展模式的弊端,需要转变经济发展方式,建立以消费为主导,消费、投资和出口协调拉动的经济发展模式。通过论述经济与社会发展之间的关系,探讨制约我国扩大消费实践中存在的制约因素,并针对这些影响因素提出合理的政策建议。首先,论证建立以消费为主导的发展模式,是实现经济社会可持续发展的必由之路;其次,分别分析现行分配制度、经济发展模式和供给结构对扩大消费的制约作用;最后,将扩大消费的对策放在限制政府对市场的干预行为,提高居民的收入水平、完善消费品供给结构、提高农民收入、健全基本公共服务体系、稳定物价等6个方面。%With the development of economy and community, the traditional economic growth mode reveals its disadvantages. The proportion of consumption must be increased to get over the difficulty. This article looks for the restraining factors which hinder the expansion of consumption by analyzing the relationship between the economic and social development. First, we can arrive at conclusion from the analysis that it is the only way of social and economic sustainable develop- ment to establish consumption for the leading model of development; Second, the paper analyzes consumption restriction role of the distribution system, the model of economic development and the supply structure. Third, the article focuses the points of application on limiting the govern- ment to market intervention behavior;raising the income level of resident;perfecting goods supply structure;improving farmers' income;constructing basic public service system and stabilizing com- modity prices.

  7. Accessory Genes Confer a High Replication Rate to Virulent Feline Immunodeficiency Virus

    OpenAIRE

    Troyer, Ryan M.; Thompson, Jesse; Elder, John H.; VandeWoude, Sue

    2013-01-01

    Feline immunodeficiency virus (FIV) is a lentivirus that causes AIDS in domestic cats, similar to human immunodeficiency virus (HIV)/AIDS in humans. The FIV accessory protein Vif abrogates the inhibition of infection by cat APOBEC3 restriction factors. FIV also encodes a multifunctional OrfA accessory protein that has characteristics similar to HIV Tat, Vpu, Vpr, and Nef. To examine the role of vif and orfA accessory genes in FIV replication and pathogenicity, we generated chimeras between tw...

  8. Reduced Insulin/Insulin-like Growth Factor-1 Signaling and Dietary Restriction Inhibit Translation but Preserve Muscle Mass in Caenorhabditis elegans

    Energy Technology Data Exchange (ETDEWEB)

    Depuydt, Geert; Xie, Fang; Petyuk, Vladislav A.; Shanmugam, Nilesh; Smolders, Arne; Dhondt, Ineke; Brewer, Heather M.; Camp, David G.; Smith, Richard D.; Braeckman, Bart P.

    2013-09-03

    Reduced signaling through the C. elegans insulin/IGF1 like tyrosine kinase receptor daf2 and dietary restriction via bacterial dilution are two well-characterized lifespan-extending interventions that operate in parallel or through (partially) independent mechanisms. Using accurate mass and time tag LCMS/MS quantitative proteomics we detected that the abundance of a large number of ribosomal subunits is decreased in response to dietary restriction as well as in the daf2(e1370) insulin/IGF1 receptor mutant. In addition, general protein synthesis levels in these long-lived worms are repressed. Surprisingly, ribosomal transcript levels were not correlated to actual protein abundance, suggesting that posttranscriptional regulation determines ribosome content. Proteomics also revealed increased presence of many structural muscle cell components in long-lived worms, which appears to result from prioritized preservation of muscle cell volume in nutrient-poor conditions or low insulin-like signaling. Activation of DAF16, but not diet-restriction, stimulates mRNA expression of muscle-related genes to prevent muscle atrophy. Important daf2 specific proteome changes include overexpression of aerobic metabolism enzymes and a general activation of stress responsive and immune defense systems, while increased abundance of many protein subunits of the proteasome core complex is a DR-specific characteristic.

  9. A Traffic Restriction Scheme for Enhancing Carpooling

    Directory of Open Access Journals (Sweden)

    Dong Ding

    2017-01-01

    Full Text Available For the purpose of alleviating traffic congestion, this paper proposes a scheme to encourage travelers to carpool by traffic restriction. By a variational inequity we describe travelers’ mode (solo driving and carpooling and route choice under user equilibrium principle in the context of fixed demand and detect the performance of a simple network with various restriction links, restriction proportions, and carpooling costs. Then the optimal traffic restriction scheme aiming at minimal total travel cost is designed through a bilevel program and applied to a Sioux Fall network example with genetic algorithm. According to various requirements, optimal restriction regions and proportions for restricted automobiles are captured. From the results it is found that traffic restriction scheme is possible to enhance carpooling and alleviate congestion. However, higher carpooling demand is not always helpful to the whole network. The topology of network, OD demand, and carpooling cost are included in the factors influencing the performance of the traffic system.

  10. Investigation Analysis of the City Inhabitants Participate Community Sports Motivation and Its Restrictive Factors%城市居民参加社区体育动机及其制约因素的调查分析

    Institute of Scientific and Technical Information of China (English)

    葛冰

    2012-01-01

    Take the Jilin Province partial city community inhabitants as the sample,investigate the motivation and the restrictive factors from the questionnaire that city inhabitants participates in the community sports,using the mathematical statistic method,discussion the difference of the motivation and the restrictive factors that community inhabitants participates in community sports.Result show:24.1% city inhabitants participate in community sports above 3 time/week;The first three motivation that inhabitants participates in the community sports is the enhance physical,the leisure and entertainment,the fitness and loses weight;The restriction factors existence significant differences that the city inhabitants participate in community sports in physiology,psychology,facilities,society and so on.%以吉林省部分城市社区居民为样本,对城市居民参加社区体育动机及其制约因素进行问卷调查,运用数理统计方法探讨城市居民参加社区体育动机和制约因素的差异。结果显示:有24.1%的城市居民参加3次/周以上的社区体育活动;参加社区体育动机前三位的是增强体质、休闲娱乐、健美减肥;城市居民参加社区体育的制约因素在生理、心理、设施和社会等层面存在显著差异。

  11. An Analysis on Institutional Restriction Factor of Financial Holding Company Development in China%我国金融控股公司发展的制度性制约因素分析

    Institute of Scientific and Technical Information of China (English)

    成娜

    2012-01-01

    我国没有专门的金融控股公司法,但是事实上存在各种类型的金融控股公司。制约金融控股股公司的发展的因素除法律因素外,还包括公司转投资限制、母公司融资限制和税收制度限制等。在分业监管体制下.我国金融控股公司立法很难有实质性突破,研究分析专门立法之外的因素更具有现实意义。%There is no special law on financial holding companies, but in fact there exist many kinds of financial holding compa- nies. Apart from legal factor, restrictions on company investment transfer, parent company financing and taxation system all restrict the development of financial holding companies. Under the separated supervision flame, making a law on financial holding companies is hard to make a material progress. Therefore, it is meaningful to study and analyze other factors beyond legal factor.

  12. Impacts of Left Lane Truck Restriction on Urban Freeways

    OpenAIRE

    Yang, Choon-Heon; Regan, A C

    2007-01-01

    This paper examines the impacts of truck lane restriction on urban freeways using traffic simulation models. The study includes three main parts: Part (1) provides insights into conditions under which truck lane restrictions would work well; Part (2) identifies the best number of lanes to restrict and shows that this is an important factor in the success of lane restriction; Part (3) investigates potential impacts of truck lane restriction through a case study using a region with some of the ...

  13. Restrictions and Proportionality

    DEFF Research Database (Denmark)

    Werlauff, Erik

    2009-01-01

    The article discusses three central aspects of the freedoms under European Community law, namely 1) the prohibition against restrictions as an important extension of the prohibition against discrimination, 2) a prohibition against exit restrictions which is just as important as the prohibition...... against host country restrictions, but which is often not recognised to the same extent by national law, and 3) the importance of also identifying and recognising an exit restriction, so that it is possible to achieve the required test of appropriateness and proportionality in relation to the rule...

  14. Calorie restriction minimizes activation of insulin signaling in response to glucose: potential involvement of the growth hormone-insulin-like growth factor 1 axis.

    Science.gov (United States)

    Hayashi, Hiroko; Yamaza, Haruyoshi; Komatsu, Toshimitsu; Park, Seongjoon; Chiba, Takuya; Higami, Yoshikazu; Nagayasu, Takeshi; Shimokawa, Isao

    2008-09-01

    Calorie restriction (CR) may modulate insulin signaling in response to energy intake through suppression of the growth hormone (GH)-IGF-1 axis. We investigated the glucose-stimulated serum insulin response and subsequent alterations in insulin receptor (IR), Akt, and FoxO1 in the rat liver and quadriceps femoris muscle (QFM). Nine-month-old wild-type (W) male Wistar rats fed ad libitum (AL) or a 30% CR diet initiated at 6 weeks of age and GH-suppressed transgenic (Tg) rats fed AL were killed 15 min after intraperitoneal injection of glucose or saline. In W-AL rats, the serum insulin concentration was elevated by glucose injection. Concomitantly, the phosphorylated (p)-IR and p-Akt levels were increased in both tissues. The active FoxO1 level was decreased in the liver, but not significantly in the QFM. In W-CR and Tg-AL rats, the serum insulin response was lower, and no significant changes were noted for the p-IR, p-Akt, or active FoxO1 levels in the liver. In the QFM, the p-Akt level was increased in W-CR and Tg-AL rats with an insignificant elevation of p-IR levels. The phenotypic similarity of W-CR and Tg-AL rats suggest that CR minimizes activation of insulin signaling in response to energy intake mostly through the GH-IGF-1 axis.

  15. Role of bed nucleus of the stria terminalis corticotrophin-releasing factor receptors in frustration stress-induced binge-like palatable food consumption in female rats with a history of food restriction.

    Science.gov (United States)

    Micioni Di Bonaventura, Maria Vittoria; Ciccocioppo, Roberto; Romano, Adele; Bossert, Jennifer M; Rice, Kenner C; Ubaldi, Massimo; St Laurent, Robyn; Gaetani, Silvana; Massi, Maurizio; Shaham, Yavin; Cifani, Carlo

    2014-08-20

    We developed recently a binge-eating model in which female rats with a history of intermittent food restriction show binge-like palatable food consumption after 15 min exposure to the sight of the palatable food. This "frustration stress" manipulation also activates the hypothalamic-pituitary-adrenal stress axis. Here, we determined the role of the stress neurohormone corticotropin-releasing factor (CRF) in stress-induced binge eating in our model. We also assessed the role of CRF receptors in the bed nucleus of the stria terminalis (BNST), a brain region implicated in stress responses and stress-induced drug seeking, in stress-induced binge eating. We used four groups that were first exposed or not exposed to repeated intermittent cycles of regular chow food restriction during which they were also given intermittent access to high-caloric palatable food. On the test day, we either exposed or did not expose the rats to the sight of the palatable food for 15 min (frustration stress) before assessing food consumption for 2 h. We found that systemic injections of the CRF1 receptor antagonist R121919 (2,5-dimethyl-3-(6-dimethyl-4-methylpyridin-3-yl)-7 dipropylamino pyrazolo[1,5-a]pyrimidine) (10-20 mg/kg) and BNST (25-50 ng/side) or ventricular (1000 ng) injections of the nonselective CRF receptor antagonist D-Phe-CRF(12-41) decreased frustration stress-induced binge eating in rats with a history of food restriction. Frustration stress also increased Fos (a neuronal activity marker) expression in ventral and dorsal BNST. Results demonstrate a critical role of CRF receptors in BNST in stress-induced binge eating in our rat model. CRF1 receptor antagonists may represent a novel pharmacological treatment for bingeing-related eating disorders.

  16. 中国竞技排球发展制约因素的研究%Study on the Restrictive Factors of the Development of the Chinese Competitive Volleyball

    Institute of Scientific and Technical Information of China (English)

    古松; 钟秉枢

    2012-01-01

    By the method of questionnaire and factor analysis,the research takes the research objects of the officials of China Volleyball Management Center,volleyball scholar,national team coaches,coaches of men's and women's volleyball clubs participating in the National Volleyball League,international and national volleyball referees.Major restrictive factors in the development on the Chinese competitive volleyball have been researched and analyzed.The result shows that current major factors restricting the development of Chinese competitive volleyball are: management models,athletes' culture quality,volleyball club,training effect,the effect of reserve training and coaches.%采用问卷调查、因子分析法以中国排球管理中心相关领导,排球学者,国家队教练员,参加全国排球甲A联赛的各俱乐部男女排教练员和国际、国家级排球裁判员等为调查对象,对当前中国竞技排球发展过程中的主要制约因素进行研究并对各因素进行分析。结果显示,当前制约中国竞技排球发展的主要因素有:管理模式、运动员文化素质、排球俱乐部、训练影响、后备培养和教练员影响。

  17. Psychological factors in analogous thinking and their restriction%类比思维的心理因素及其制约

    Institute of Scientific and Technical Information of China (English)

    张晓芒

    2006-01-01

    AIM: To investigate the role of certain psychological factors in the process of new analogous combination on the basis of complete perceptual materials.METHODS: By means of evaluation of critical thinking, the psychological factors in the process of analogous thinking were investigated.RESULTS: In the process of analogous thinking, how to choose and reflect the analogous objects has its proper use of analogous mode of thinking. At the same time, it is also influenced by certain psychological factors.CONCLUSION: Analogous thinking plays an important role as thinking tool in the process of recognizing new things and solving new problems, or explaining abstract affair with simple reasons.%目的:探讨一定的心理因素在完整的知觉材料基础上进行新的类比组合过程中的作用.方法:以批判性思维的评价方法,对类比思维过程中心理因素进行研究.结果:在类比思维的过程中,如何选择、映射类比事物,不但有着正确的类比思维方法的运用,同时它也受到一定的心理因素的影响.结论:类比思维在认识新事物、解决新问题的过程中,或者以简单的道理说明抽象事理的过程中,都发挥着重要的思维工具作用.

  18. 苏南地区乡村城市化制约因素、动力机制与对策%RESTRICTED FACTORS, DRIVE MECHANISM AND COUNTERMEARES OF RURAL URBANIZATION IN SOUTH JIANGSU

    Institute of Scientific and Technical Information of China (English)

    徐海贤; 庄林德

    2001-01-01

    苏南地区现行的村镇企业生产经营模式、产品销售方式,农村建设用地使用机制、农民的观念意识等严重制约着农村城市化进程.本文通过对这些制约因素及农村城市化动力机制的分析,提出了加速苏南地区农村城市化的若干调控措施.%At the beginning of this century, some problems restricted thedevelopment of rural urbanization ,which include the present production and management patterns ,products selling modes in rural enterprises,rural land use mechanism and improvement of peasant 's idea. The paper analyses the restricted factors and the new mechanism of rural urbanization. Then the authors propose several countermeasures to push rural urbanization in South Jiangsu.

  19. Change in proportional protein intake in a 10-week energy-restricted low- or high-fat diet, in relation to changes in body size and metabolic factors

    DEFF Research Database (Denmark)

    Stocks, Tanja; Taylor, Moira A; Ängquist, Lars

    2013-01-01

    Objective: To investigate in a secondary analysis of a randomised trial the effects of a low-/high-fat diet and reported change from baseline in energy% from protein (prot%), in relation to changes in body size and metabolic factors. Methods: Obese adults (n = 771) were randomised to a 600 kcal e...... increased the percentage energy intake from protein showed the greatest reduction in weight and cholesterol, and a triglyceride reduction equally large to that of participants on a high-fat diet. Copyright © 2013 S. Karger GmbH, Freiburg.......Objective: To investigate in a secondary analysis of a randomised trial the effects of a low-/high-fat diet and reported change from baseline in energy% from protein (prot%), in relation to changes in body size and metabolic factors. Methods: Obese adults (n = 771) were randomised to a 600 kcal...... energy-deficient low-fat (20-25 fat%) or high-fat (40-45 fat%) diet over 10 weeks. Dietary intake data at baseline and during the intervention were available in 585 completers. We used linear regression to calculate the combined effects of randomised group and groups of prot% change (2) on outcomes...

  20. Restricting Factors of Foreign Language Teachers Professional Development and Its Countermeasures%高职外语教师专业发展的制约因素及对策

    Institute of Scientific and Technical Information of China (English)

    温素云

    2014-01-01

    本文在对河北省3所高职高专院校英语教师的问卷调查的基础上,探究了高职高专英语教师的专业发展需求和制约专业发展的几个因素,并提出促进高职外语教师专业发展的相应对策。%Based on questionnaire survey in Hebei province 3 vocational college English teachers, this paper is to explore the needs and restrict factors of English teachers professional development in higher vocational colleges,and put forward the corresponding countermeasures to promote foreign language teacher professional development.

  1. Functional high-throughput screening identifies the miR-15 microRNA family as cellular restriction factors for Salmonella infection.

    Science.gov (United States)

    Maudet, Claire; Mano, Miguel; Sunkavalli, Ushasree; Sharan, Malvika; Giacca, Mauro; Förstner, Konrad U; Eulalio, Ana

    2014-08-22

    Increasing evidence suggests an important role for miRNAs in the molecular interplay between bacterial pathogens and host cells. Here we perform a fluorescence microscopy-based screen using a library of miRNA mimics and demonstrate that miRNAs modulate Salmonella infection. Several members of the miR-15 miRNA family were among the 17 miRNAs that more efficiently inhibit Salmonella infection. We discovered that these miRNAs are downregulated during Salmonella infection, through the inhibition of the transcription factor E2F1. Analysis of miR-15 family targets revealed that derepression of cyclin D1 and the consequent promotion of G1/S transition are crucial for Salmonella intracellular proliferation. In addition, Salmonella induces G2/M cell cycle arrest in infected cells, further promoting its replication. Overall, these findings uncover a mechanism whereby Salmonella renders host cells more susceptible to infection by controlling cell cycle progression through the active modulation of host cell miRNAs.

  2. Adipogenic placenta-derived mesenchymal stem cells are not lineage restricted by withdrawing extrinsic factors: developing a novel visual angle in stem cell biology.

    Science.gov (United States)

    Hu, C; Cao, H; Pan, X; Li, J; He, J; Pan, Q; Xin, J; Yu, X; Li, J; Wang, Y; Zhu, D; Li, L

    2016-03-17

    Current evidence implies that differentiated bone marrow mesenchymal stem cells (BMMSCs) can act as progenitor cells and transdifferentiate across lineage boundaries. However, whether this unrestricted lineage has specificities depending on the stem cell type is unknown. Placental-derived mesenchymal stem cells (PDMSCs), an easily accessible and less invasive source, are extremely useful materials in current stem cell therapies. No studies have comprehensively analyzed the transition in morphology, surface antigens, metabolism and multilineage potency of differentiated PDMSCs after their dedifferentiation. In this study, we showed that after withdrawing extrinsic factors, adipogenic PDMSCs reverted to a primitive cell population and retained stem cell characteristics. The mitochondrial network during differentiation and dedifferentiation may serve as a marker of absent or acquired pluripotency in various stem cell models. The new population proliferated faster than unmanipulated PDMSCs and could be differentiated into adipocytes, osteocytes and hepatocytes. The cell adhesion molecules (CAMs) signaling pathway and extracellular matrix (ECM) components modulate cell behavior and enable the cells to proliferate or differentiate during the differentiation, dedifferentiation and redifferentiation processes in our study. These observations indicate that the dedifferentiated PDMSCs are distinguishable from the original PDMSCs and may serve as a novel source in stem cell biology and cell-based therapeutic strategies. Furthermore, whether PDMSCs differentiated into other lineages can be dedifferentiated to a primitive cell population needs to be investigated.

  3. Adipogenic placenta-derived mesenchymal stem cells are not lineage restricted by withdrawing extrinsic factors: developing a novel visual angle in stem cell biology

    Science.gov (United States)

    Hu, C; Cao, H; Pan, X; Li, J; He, J; Pan, Q; Xin, J; Yu, X; Li, J; Wang, Y; Zhu, D; Li, L

    2016-01-01

    Current evidence implies that differentiated bone marrow mesenchymal stem cells (BMMSCs) can act as progenitor cells and transdifferentiate across lineage boundaries. However, whether this unrestricted lineage has specificities depending on the stem cell type is unknown. Placental-derived mesenchymal stem cells (PDMSCs), an easily accessible and less invasive source, are extremely useful materials in current stem cell therapies. No studies have comprehensively analyzed the transition in morphology, surface antigens, metabolism and multilineage potency of differentiated PDMSCs after their dedifferentiation. In this study, we showed that after withdrawing extrinsic factors, adipogenic PDMSCs reverted to a primitive cell population and retained stem cell characteristics. The mitochondrial network during differentiation and dedifferentiation may serve as a marker of absent or acquired pluripotency in various stem cell models. The new population proliferated faster than unmanipulated PDMSCs and could be differentiated into adipocytes, osteocytes and hepatocytes. The cell adhesion molecules (CAMs) signaling pathway and extracellular matrix (ECM) components modulate cell behavior and enable the cells to proliferate or differentiate during the differentiation, dedifferentiation and redifferentiation processes in our study. These observations indicate that the dedifferentiated PDMSCs are distinguishable from the original PDMSCs and may serve as a novel source in stem cell biology and cell-based therapeutic strategies. Furthermore, whether PDMSCs differentiated into other lineages can be dedifferentiated to a primitive cell population needs to be investigated. PMID:26986509

  4. 17β-estradiol protects primary macrophages against HIV infection through induction of interferon-alpha.

    Science.gov (United States)

    Tasker, Carley; Ding, Jian; Schmolke, Mirco; Rivera-Medina, Amariliz; García-Sastre, Adolfo; Chang, Theresa L

    2014-05-01

    Estrogen has been shown to increase resistance to HIV/SIV transmission by increasing the thickness of the genital epithelium. The immunological role of estrogen in HIV infection of primary target cells is less well characterized. We have found that primary macrophages are a target for anti-HIV activity of 17β-estradiol (E2). E2 did not affect surface expression of CD4 and HIV co-receptors nor HIV attachment to monocyte-derived macrophages (MDMs). In addition, E2 treatment blocked infection by a co-receptor-independent HIV-1VSV-G pseudotyped virus. Quantitative polymerase chain reaction analysis of HIV reverse transcribed DNA products indicated that E2 blocked HIV reverse transcription. E2 upregulated gene expression of interferons (IFNs) in MDMs from multiple donors. However, induction of host restriction factors APOBEC3G, APOBEC3F, or SAMHD1 was not consistent, with exception of APOBEC3A. Anti-HIV activity of E2 was abolished in the presence of IFN-α neutralizing antibody, and was absent in bone marrow-derived macrophages from IFN-α receptor deficient mice. Interestingly, HIV overcame E2-mediated HIV inhibition by suppressing induction of IFNs when MDMs were exposed to HIV before E2 treatment. These results offer a new mechanism of E2 on HIV inhibition. Future studies on the interplay between HIV and E2-mediated innate immune responses will likely provide insights relevant for development of effective strategies for HIV prevention.

  5. Late gestational nutrient restriction

    DEFF Research Database (Denmark)

    Tygesen, Malin Plumhoff; Nielsen, Mette Olaf; Nørgaard, Peder;

    2008-01-01

    We investigated the effect of 50% nutrient restriction during the last 6 weeks of gestation on twin-pregnant ewes' plasma glucose, non-esterified fatty acid, ß-hydroxybutyrate, insulin, IGF-1 and leptin concentrations and the effects on lamb birth weight and ewes' lactation performance. Plasma...... metabolite and hormone concentrations in restricted ewes suggest that maternal tissues were being mobilised. Despite the ewes' adaptations their lambs weighed significantly less at birth. Furthermore, colostrum and milk yields were markedly reduced up until the latest measurement at 3 weeks post partum...

  6. Training Restricted Boltzmann Machines

    DEFF Research Database (Denmark)

    Fischer, Asja

    Restricted Boltzmann machines (RBMs) are probabilistic graphical models that can also be interpreted as stochastic neural networks. Training RBMs is known to be challenging. Computing the likelihood of the model parameters or its gradient is in general computationally intensive. Thus, training...

  7. Bilinear Fourier restriction theorems

    CERN Document Server

    Demeter, Ciprian

    2012-01-01

    We provide a general scheme for proving $L^p$ estimates for certain bilinear Fourier restrictions outside the locally $L^2$ setting. As an application, we show how such estimates follow for the lacunary polygon. In contrast with prior approaches, our argument avoids any use of the Rubio de Francia Littlewood--Paley inequality.

  8. Analysis of Risk Factors for Fetal Growth Restriction and Delivery Timing%胎儿生长受限危险因素及分娩时机的分析

    Institute of Scientific and Technical Information of China (English)

    崔世红; 孙俊燕; 陈娟; 李园园; 杭中霞; 申琳娜; 职云晓; 高亚南

    2015-01-01

    Objective:To explore the related risk factors for fetal growth restriction and time to termination of pregnancy.Method:The clinical data of 173 neonates with FGR(FGR group),180 neonates with normal weight(normal group) and the parturient women in the Third Affiliated Hospital of Zhengzhou University were selected from January 2013 to November 2014,they were analyzed retrospectively.Result:The high risk factors of fetal growth restriction were: gestational hypertension disease (P=0.000,OR=20.440,95%CI 8.499-49.156),oligohydramnios(P=0.000, OR=5.652,95%CI 2.195-14.555),gestational diabetes(P=0.018,OR=2.763,95%CI 1.192-6.400) and anemia (P=0.032,OR=1.708,95%CI 1.047-2.786).With the gestational age greater, the weight of the newborn was higher, the prognosis was better,the differences were statistically significant(P<0.05).Conclusion:Gestational hypertension disease, oligohydramnios, gestational diabetes and anemia are high risk factors of fetal growth restriction.To strengthen pregnancy care and custody,the standard treatment of obstetric complications, timely termination of pregnancy is main measures to reduce perinatal mortality.%目的:探讨胎儿生长受限的相关危险因素及终止妊娠时机。方法:对2013年1月-2014年11月在郑州大学第三附属医院分娩的173例FGR新生儿(FGR组)及180例正常体重新生儿(对照组)及其产妇病历资料进行回顾性分析。结果:胎儿生长受限的高危因素有:妊娠期高血压疾病(P=0.000,OR=20.440,95%CI 8.499~49.156)、羊水过少(P=0.000,OR=5.652,95%CI 2.195~14.555)、妊娠期糖尿病(P=0.018, OR=2.763,95%CI 1.192~6.400)和贫血(P=0.032,OR=1.708,95%CI 1.047~2.786)。孕周越大,新生儿体重越重,预后越好,差异均有统计学意义(P<0.05)。结论:妊娠期高血压疾病、羊水过少、妊娠期糖尿病、贫血是胎儿生长受限的高危因素,加强孕期保健及监护,规范治疗产科并发症

  9. Restricted and quasi-toral restricted Lie-Rinehart algebras

    Directory of Open Access Journals (Sweden)

    Sun Bing

    2015-09-01

    Full Text Available In this paper, we introduce the definition of restrictable Lie-Rinehart algebras, the concept of restrictability is by far more tractable than that of a restricted Lie-Rinehart algebra. Moreover, we obtain some properties of p-mappings and restrictable Lie-Rinehart algebras. Finally, we give some sufficient conditions for the commutativity of quasi-toral restricted Lie-Rinehart algebras and study how a quasi-toral restricted Lie-Rinehart algebra with zero center and of minimal dimension should be.

  10. Mutation of Breast Cancer Cell Genomic DNA by APOBEC3B

    Science.gov (United States)

    2013-09-01

    combine to provide innate immunity to a variety of DNA-based parasitic elements17,18. A well-studied example is the cDNA replication intermediate of...carcinoma THCA 384 0–4.1 0.18 326 3–98 20 22 25 0.077 1.2 Glioblastoma multiforme GBM 169 0.014–2.0 0.22 167 1–173 28 34 114 0.68 7.9 Kidney renal...papillary cell carcinoma KIRP 76 0.0079–3.0 0.24 100 15–214 64 69 18 0.18 1.0 Kidney renal clear-cell carcinoma KIRC 480 0.011–4.5 0.29 244 6–696 73 92

  11. Restriction of Helmholtz Model

    Directory of Open Access Journals (Sweden)

    V.M. Polunin

    2014-07-01

    Full Text Available The results of the experimental studies of physical mechanisms of energy dissipation in the oscillating system in which air cavity held by the forces of magnetic levitation is used as the elastic element, and magnetic fluid prepared on the basis of dispersing media with different viscosity level is used as the inertial element are considered in the article. Based on the obtained results the conclusion on the restriction of the applicability of Helmholtz equation, caused by boundary effects is made.

  12. License restrictions at Barnwell

    Energy Technology Data Exchange (ETDEWEB)

    Autry, V.R. [S.C. Dept. of Health and Environmental Control, Columbia, SC (United States). Bureau of Radiological Health

    1991-12-31

    The State of South Carolina was delegated the authority by the US Nuclear Regulatory Commission to regulate the receipt, possession, use and disposal of radioactive material as an Agreement State. Since 1970, the state has been the principal regulatory authority for the Barnwell Low-Level Waste Disposal Facility operated by Chem-Nuclear Systems, Inc. The radioactive material license issued authorizing the receipt and disposal of low-level waste contains numerous restrictions to ensure environmental protection and compliance with shallow land disposal performance criteria. Low-level waste has evolved from minimally contaminated items to complex waste streams containing high concentrations of radionuclides and processing chemicals which necessitated these restrictions. Additionally, some waste with their specific radionuclides and concentration levels, many classified as low-level radioactive waste, are not appropriate for shallow land disposal unless additional precautions are taken. This paper will represent a number of these restrictions, the rationale for them, and how they are being dealt with at the Barnwell disposal facility.

  13. The Examination of China’s New Medical Reform Based on Restrictive Factors in British Medical Reform%基于英国医改制约性因素审视我国新医改

    Institute of Scientific and Technical Information of China (English)

    王演艺

    2014-01-01

    As the first country established universal health insurance in the world, UK has been devoted to construct the fairness and welfare of National Health Service(NHS) with constant development and improvement. It focuses on the reform process of NHS since the beginning of this century and studies the deep factors restricted the reform, compared with the current situation of health care system under China’s new medical reform since 2006, putting forward enlightenment to China’s reform.%作为世界上最早建立全民医疗保障的国家,英国一直致力于其医疗服务系统(NHS)公平性与福利性的构建,不断进行发展与完善。文章重点关注本世纪以来NHS 的改革历程,研究影响其改革成效的深层次制约性因素,同时对照我国2006年启动新医疗改革后国内卫生医疗服务体系的现状,提出其对我国新医改的启示。

  14. 浅谈残疾儿童参与全民健身的制约因素及发展对策%Discussion on Restricting Factors and Developing Measurements of Disable Children Participating in National Fitness Activity

    Institute of Scientific and Technical Information of China (English)

    蔡勇刚; 张雷

    2011-01-01

    Through using the method of literature review, this paper makes analysis on restricting factors of disable children participating in national fitness activity from economy, policy, and cultural philosophy. Based on exiting problems, some measurements are put forward. The main purpose is to promote the physical fitness of disable children and provide the reference for national fitness development.%本文采用文献资料的研究方法,对残疾儿童参与全民健身的制约因素从经济、政策、思想文化意识三个角度进行分析,针对残疾儿童全面参与健身中遇到的问题,提出相应的对策和建议,旨在为残疾儿童提高身体素质、参与体育锻炼和全民健身的普及提供一定的理论参考依据。

  15. 高校学报数字出版的制约因素及其对策思考%On Restrictive Factors and Countermeasures of University Journal Digital Publishing

    Institute of Scientific and Technical Information of China (English)

    禤展图

    2014-01-01

    University Journal Digital Publishing is the requirement of the development of the times. However it is restricted by the fol-lowing factors: ideas,scientific evaluation mechanism,equipment and technology,and professional criteria,etc. In order to realize university journal digital publishing,the old ideas must be changed,the scientific evaluation mechanism be improved,the profit pat-tern of“double benefit”be carried out,the intensity of support be increased,the comprehensive qualities of editors and management personnel be promoted,and a shareable digital publishing platform be established.%高校学报数字出版是时代发展的要求。高校学报数字出版受思想观念、科研评价机制、设备和技术、行业标准等诸因素制约。要实现高校学报数字出版必须转变观念,完善科研评价机制,实行“双效益”的盈利模式,加大扶持力度,提升编辑和管理人员的综合素质,建立可共享的数字出版平台。

  16. Expression of the ctenophore Brain Factor 1 forkhead gene ortholog (ctenoBF-1) mRNA is restricted to the presumptive mouth and feeding apparatus: implications for axial organization in the Metazoa

    Science.gov (United States)

    Yamada, Atsuko; Martindale, Mark Q.

    2002-01-01

    Ctenophores are thoroughly modern animals whose ancestors are derived from a separate evolutionary branch than that of other eumetazoans. Their major longitudinal body axis is the oral-aboral axis. An apical sense organ, called the apical organ, is located at the aboral pole and contains a highly innervated statocyst and photodetecting cells. The apical organ integrates sensory information and controls the locomotory apparatus of ctenophores, the eight longitudinal rows of ctene/comb plates. In an effort to understand the developmental and evolutionary organization of axial properties of ctenophores we have isolated a forkhead gene from the Brain Factor 1 (BF-1) family. This gene, ctenoBF-1, is the first full-length nuclear gene reported from ctenophores. This makes ctenophores the most basal metazoan (to date) known to express definitive forkhead class transcription factors. Orthologs of BF-1 in vertebrates, Drosophila, and Caenorhabditis elegans are expressed in anterior neural structures. Surprisingly, in situ hybridizations with ctenoBF-1 antisense riboprobes show that this gene is not expressed in the apical organ of ctenophores. CtenoBF-1 is expressed prior to first cleavage. Transcripts become localized to the aboral pole by the 8-cell stage and are inherited by ectodermal micromeres generated from this region at the 16- and 32-cell stages. Expression in subsets of these cells persists and is seen around the edge of the blastopore (presumptive mouth) and in distinct ectodermal regions along the tentacular poles. Following gastrulation, stomodeal expression begins to fade and intense staining becomes restricted to two distinct domains in each tentacular feeding apparatus. We suggest that the apical organ is not homologous to the brain of bilaterians but that the oral pole of ctenophores corresponds to the anterior pole of bilaterian animals.

  17. 限制刑事技术专业实战技能训练开展的因素及对策%The Factors Restricting Combat Skills Training of Criminal Technology Major and the Countermeasures

    Institute of Scientific and Technical Information of China (English)

    张颖

    2014-01-01

    公安院校刑事技术专业的人才培养目标是理论基础扎实、专业知识系统并且实战能力强的应用型复合型刑侦人员,当前刑事犯罪的特点对刑侦人员的实战技能提出了更高的要求。实战技能训练作为培养和提升公安院校刑事技术专业学生实战技能的重要手段和途径,由于受到来自学生、教师以及学校等因素的限制并没有取得理想的教学效果,本文分析了这些因素产生的原因并提出了转变学生观念扭转学习态度,提升教师业务能力和水平,聘请公安机关刑事技术人员为实践教学教官,加强实验室建设,以及建立校外实践训练基地等相应对策。%The training goal of criminal technology major in public security college is to cultivate the practical and versatile talents who have solid theoretical background, professional knowledge system, and outstanding combat ability. However, the characteristics of new crime put forward a higher requirement for the actual combat ability of criminal investigators. As an important way to train and promote the criminal technology majors’ combat ability, the combat skills training fails to receive satisfied teaching effects out of some restrictions from students, teachers and the college. This paper analyses the reasons of these restricted factors and presents the countermeasures accordingly, such as changing the students’ learning idea and attitudes, improving the teachers’ proficiency and teaching level, appointing the criminal technicians in public security organs to be practicing teachers, improving the lab, establishing the practice training base outside school, etc.

  18. Caloric restriction-associated remodeling of rat white adipose tissue: effects on the growth hormone/insulin-like growth factor-1 axis, sterol regulatory element binding protein-1, and macrophage infiltration.

    Science.gov (United States)

    Chujo, Yoshikazu; Fujii, Namiki; Okita, Naoyuki; Konishi, Tomokazu; Narita, Takumi; Yamada, Atsushi; Haruyama, Yushi; Tashiro, Kosuke; Chiba, Takuya; Shimokawa, Isao; Higami, Yoshikazu

    2013-08-01

    The role of the growth hormone (GH)-insulin-like growth factor (IGF)-1 axis in the lifelong caloric restriction (CR)-associated remodeling of white adipose tissue (WAT), adipocyte size, and gene expression profiles was explored in this study. We analyzed the WAT morphology of 6-7-month-old wild-type Wistar rats fed ad libitum (WdAL) or subjected to CR (WdCR), and of heterozygous transgenic dwarf rats bearing an anti-sense GH transgene fed ad libitum (TgAL) or subjected to CR (TgCR). Although less effective in TgAL, the adipocyte size was significantly reduced in WdCR compared with WdAL. This CR effect was blunted in Tg rats. We also used high-density oligonucleotide microarrays to examine the gene expression profile of WAT of WdAL, WdCR, and TgAL rats. The gene expression profile of WdCR, but not TgAL, differed greatly from that of WdAL. The gene clusters with the largest changes induced by CR but not by Tg were genes involved in lipid biosynthesis and inflammation, particularly sterol regulatory element binding proteins (SREBPs)-regulated and macrophage-related genes, respectively. Real-time reverse-transcription polymerase chain reaction analysis confirmed that the expression of SREBP-1 and its downstream targets was upregulated, whereas the macrophage-related genes were downregulated in WdCR, but not in TgAL. In addition, CR affected the gene expression profile of Tg rats similarly to wild-type rats. Our findings suggest that CR-associated remodeling of WAT, which involves SREBP-1-mediated transcriptional activation and suppression of macrophage infiltration, is regulated in a GH-IGF-1-independent manner.

  19. Analysis of restricting factors of long-term care of stroke survivors in community%社区脑卒中患者长期保健的制约因素分析

    Institute of Scientific and Technical Information of China (English)

    张亚奇; 张振香; 陈颖; 刘腊梅; 张秋实

    2014-01-01

    Objective To investigate the restricting factors of long-term care of stroke survivors in community.Methods The phenomenological methodology was adopted in the study.Sixteen stroke survivors were interviewed.Data were analyzed by Colaizzi's method.Results Three themes were found,including physical barriers,incorrect attitude towards disease,and defects of community health service.Conclusions On the basis of improving technology and ability,medical workers in community should consider of supporting the patients with information of disease and useful resources in a variety of ways,and improving the patients" health literacy.%目的 探讨社区脑卒中患者康复保健的制约因素.方法 采用半结构访谈法对16例社区脑卒中患者进行一对一访谈,收集患者资料,并以Colaizzi 7步分析法分析资料.结果 通过分析整理和提炼主题,归纳出躯体障碍因素,不良疾病态度以及社区卫生服务不到位3个主题.结论社区医务人员应该在提高自身技术与能力的基础上,考虑以多种方式给予患者疾病知识和健康资源信息的支持和教育,提高患者健康素养.

  20. Restrictive Factors and Historical Significance of Rectification Movement in the Later Anti-Japanese War%抗战后期敌后整风的制约因素与历史意义

    Institute of Scientific and Technical Information of China (English)

    向伟

    2015-01-01

    抗战后期,中共在全党开展整风学习运动。处在敌后的各根据地,尽管也都在规定时间内完成整风,但从当时的情况来看,这些根据地的整风受到诸多因素的制约,如党员干部对整风的重要性缺乏认识、敌后环境异常艰苦、党员与干部知识水平较低以及整风脱离实际等。分析敌后整风情况,无论从认识还是实践上,对于如今的党建工作也有一定的启发意义。%In the latter part of the Anti-Japanese War, the Chinese Communists Party carried out the rectification movement. Although the rectification was completed in a short time, from the point of view of the situation at that time, the rectification movement was restricted by many factors , such as the lack of understanding of importance of Party members and cadres ,the difficult environment in the enemy’s rear area, low level of knowledge and rectification from the reality etc. Analysis of rectification situation both from behind enemy lines, understanding and practice, also have certain enlightening significance for today ’s rectification learning.

  1. 我国公共政策参与中公民层面的制约因素分析%AN ANALYSIS OF FACTORS RESTRICTING CITIZENS FROM PARTICIPATING IN PUBLIC POLICIES

    Institute of Scientific and Technical Information of China (English)

    李占乐

    2011-01-01

    在现代社会,公民积极主动地参与政府的公共政策,除了基于自身利益追求的参与动机外,实现和促进与全体社会成员相联系的公共利益也是一个重要动机。改革开放以后,在公民个体的政策参与逐渐增多的同时,我国以民间组织为主体的各种利益团体参与政府公共政策的活动也逐渐增多。同时在我国公民的公共政策参与过程中存在的问题也十分突出。公共政策参与中公民层面的制约因素主要包括参与意识不强、参与能力不足和参与的组织化程度不高3个方面。%In modern society, citizens actively participate in the government' s public policies. In addition to participation based on the pursuit of self-interests, the achieving and promoting of the public interest involving all members of society can be another important motivation. After the reform and opening up, an increasing number of individual citizens participate in policies and meanwhile more various interest groups in China take part in more policy-related activities with civil organizations as the main body. There exist some prominent problems in the participating process. The factors restricting citizens from participating in public policy include weak sense of participation, lack of capacity for involvement and participation and low degree of organization.

  2. 贫困地区民营经济发展的制约因素及对策分析%Restricting Factors for the Growth of Private Economy in Poverty-Stricken Areas and the Strategy

    Institute of Scientific and Technical Information of China (English)

    彭贞贞; 马骥

    2014-01-01

    民营经济发展水平低是贫困地区经济发展不发达的重要原因。制约贫困地区民营经济发展的因素有脱贫致富的思想、人力资源状况、金融生态环境和技术创新水平等。促进贫困地区民营经济发展与脱贫致富必须根据民营经济产业发展需求,大力发展职业教育;优化环境,承接产业转移;创新贫困地区新型城镇化发展机制,推动地区民营经济发展;大力发展交通基础设施,破解民营经济发展瓶颈;创新民营企业管理,做大做强民营经济。%Inadequate development of the private economy is a major reason of economic underdevelopment in poverty-driven areas. Fac-tors restricting the growth of the private economy in these areas include people's lack of eagerness for creating a fortune, human resource shortage, and the poor financial environment and technological innovation ability. To shake off poverty, the areas must develop the private economy by proactively develop vocational education, improve environment for carrying on industry transfer, innovate new-type urbaniza-tion mechanism, enhance the transportation infrastructure construction, and innovate the management of private enterprises.

  3. Very strict selectional restrictions

    CERN Document Server

    Laporte, Eric; Dias, Maria Carmelita P

    2007-01-01

    We discuss the characteristics and behaviour of two parallel classes of verbs in two Romance languages, French and Portuguese. Examples of these verbs are Port. abater [gado] and Fr. abattre [b\\'etail], both meaning "slaughter [cattle]". In both languages, the definition of the class of verbs includes several features: - They have only one essential complement, which is a direct object. - The nominal distribution of the complement is very limited, i.e., few nouns can be selected as head nouns of the complement. However, this selection is not restricted to a single noun, as would be the case for verbal idioms such as Fr. monter la garde "mount guard". - We excluded from the class constructions which are reductions of more complex constructions, e.g. Port. afinar [instrumento] com "tune [instrument] with".

  4. Ecology from the Perspective of Analysis on the Factors Restricting Development of China′s Cartoon Periodicals%生态学视角下我国动漫类期刊发展制约因素探析

    Institute of Scientific and Technical Information of China (English)

    张志钊

    2014-01-01

    Anime journals as the front end of the animation industry chain,is the pioneer of the animation indus-try development.In recent years,the journal of the Chinese animation market presents the explosive growth of the deteriorating ecological environment at the same time.Elements in the system main body and anime have open,dynamic and network system,supporting policies lack of pertinence and operability,and publication man-agement system reform lags behind the policy environment;Animation industry chain of each node lack of con-tact,communication and cooperation,market orientation and layout is messy,homogeneity and low level compe-tition,the industry environment;Original animation works and journal editors and lack of business resources and environment is a major factor which restricts the healthy development of anime journals.%动漫期刊作为动漫产业链的前端,是动漫产业发展的先行者。近年来,中国动漫期刊市场呈现井喷式发展的同时其生态环境逐渐恶化。在动漫期刊这个系统主体和要素都具有开放性、动态性和网络化的系统中,扶持政策缺少针对性和可操作性以及出版市场秩序管理制度改革滞后的政策环境;动漫产业链各节点缺乏联系、沟通、合作,市场定位和布局凌乱,同质化低水平竞争的产业环境;动漫作品原创和期刊编辑、经营人才匮乏的资源环境是制约动漫期刊健康发展的主要因素。

  5. Restricted Factors and Countermeasures for the Development of Chinese Ice Hockey Players%我国冰球运动发展的制约因素及对策

    Institute of Scientific and Technical Information of China (English)

    宁文静; 王淑华

    2013-01-01

    冰球运动是一项冬季体育运动中唯一的球类集体项目,其运动水平可以代表一个国家冬季运动的总体水平。对我国冰球运动现状进行分析,找出目前我国冰球运动存在项目普及萎缩,后备人才短缺;培养体制不完善,场地、器材匮乏;教练员教练水平低,创新意识差;科技投入少,科学化训练水平低等制约因素。提出加大冰球运动后备人才培养力度;制定、完善冰球运动员培养、输送体制;提升冰球运动教练员的整体素质;强化冰球运动科学化训练体系等解决对策,为让冰球运动重新在中国的大地上蓬勃开展起来,打造中国冰球崭新的未来提供参考。%Ice hockey is the only team ball game of winter sports , its sports level can represent the winter sports level of a country .By analyzing the status of Chinese ice hockey , this paper has found out that there are many restricted factors of Chinese ice hockey , such as project popularization declining , shortages of re-served talents;training system is not perfect , lack of venues and equipments;low level of coaches , poor in-novation consciousness;low technology input , low level of scientific training .The paper puts forward that we should strengthen the reserved talents training of ice hockey; outline and perfect the training conveying system of ice hockey players;improve the overall quality of coaches;strengthen scientific training system of ice hockey and other solutions , in order to give a reference for having a great boom in ice hockey in China and creating a new future of Chinese ice hockey .

  6. Property Rights, Restrictions and Responsibilities

    DEFF Research Database (Denmark)

    Enemark, Stig

    Land Administration Systems are the basis for conceptualizing rights, restrictions and responsibilities related to people, policies and places. Property rights are normally concerned with ownership and tenure whereas restrictions usually control use and activities on land. Responsibilities relate...... more to a social, ethical commitment or attitude to environmental sustainability and good husbandry. This paper provides an overall understanding of the concept of land administration systems for dealing with rights, restrictions and responsibilities in future spatially enabled government. Finally...

  7. Dietary Restriction and Nutrient Balance in Aging

    Directory of Open Access Journals (Sweden)

    Júlia Santos

    2016-01-01

    Full Text Available Dietary regimens that favour reduced calorie intake delay aging and age-associated diseases. New evidences revealed that nutritional balance of dietary components without food restriction increases lifespan. Particular nutrients as several nitrogen sources, proteins, amino acid, and ammonium are implicated in life and healthspan regulation in different model organisms from yeast to mammals. Aging and dietary restriction interact through partially overlapping mechanisms in the activation of the conserved nutrient-signalling pathways, mainly the insulin/insulin-like growth factor (IIS and the Target Of Rapamycin (TOR. The specific nutrients of dietary regimens, their balance, and how they interact with different genes and pathways are currently being uncovered. Taking into account that dietary regimes can largely influence overall human health and changes in risk factors such as cholesterol level and blood pressure, these new findings are of great importance to fully comprehend the interplay between diet and humans health.

  8. 34周以下早产儿宫外生长发育迟缓发生的影响因素%Risk factors for extrauterine growth restriction in preterm infants with gestational age less than 34 weeks

    Institute of Scientific and Technical Information of China (English)

    曹玮; 张永红; 赵冬莹; 夏红萍; 朱天闻; 谢利娟

    2015-01-01

    ObjectiveTo investigate the correlated factors contributed to extrauterine growth restriction (EUGR) in preterm infants with the gestational age less than 34 weeks.MethodsA total of 694 preterm infants with the gestational ages less than 34 weeks were enrolled. They were classiifed into EUGR and non-EUGR groups by weight on discharge. The perinatal data, growth data, nutritional information and morbidities during hospitalization were compared between the two groups.ResultsEUGR on discharge occurred in 284 (40.9%) out of the 694 infants. The incidence of EUGR in intrauterine growth restriction (IUGR) infants was signiifcantly higher than in non-IUGR infants (P<0.01). The very low birth weight (VLBW) infants had a higher incidence of EUGR than non-VLBW infants (P<0.01). The incidence of EUGR increased with the decreases of gestational age at birth and birth weight (P<0.01). Compared with the non-EUGR group, the fasting time, the duration of parenteral nutrition, the time beginning to feed and the age to achieve full enteral feeds were signiifcantly greater in the EUGR group (P<0.01). The cumulative protein deifcit and cumulative caloric deifcit in the ifrst week of life in the EUGR group were higher than in the non-EUGR group (P<0.05). The incidences of respiratory distress syndrome, apnea, necrotizing enterocolitis and septicemia in the EUGR group were higher than in the non-EUGR group (P<0.05). The logistic regression analysis showed that birth weight, gestational age at birth and IUGR were the independent risk factors for EUGR.ConclusionsThe incidence of EUGR in infants with gestational age less than 34 weeks is high, especially in IUGR or VLBW infants. Early and aggressive nutritional strategy and prevention of apnea and septicemia may facilitate to reduce the occurrence of EUGR.%目的:研究34周以下早产儿宫外生长发育迟缓(EUGR)发生的相关因素。方法选取<34周早产儿694例,根据出院时体重分为EUGR组和非EUGR组,回顾

  9. 制约城市社区老年人参与健身活动的因素研究——基于解释结构模型视角%Research of the Individual Restricting Factors of Elderly Fitness Participation in Urban Community Based on ISM

    Institute of Scientific and Technical Information of China (English)

    任波

    2012-01-01

    This research based on ISM and analyzed the individual restricting factors of elderly fitness participation in urban community.It used the method of matrix to grading the restricting factors.Conclusion shows that the interpretative structural modeling can be classified by three grades.The purpose of this research was to provide strategy analysis and theoretical basis for community managers and elderly fitness activity promoters.%研究制约城市社区老年人健身参与的个人因素,利用ISM模型对各项指标进行分析,运用矩阵的方法对其分级。结果表明,构建的解释结构模型可以分为三级,从而为社区管理者和老年健身活动推广者提供策略分析和理论依据。

  10. 森林资源产权市场制约因素及对策分析——基于供求视角%Analysis on Forest Resource Property Market's Restriction Factors and Countermeasures: From the Perspective of Supply and Demand

    Institute of Scientific and Technical Information of China (English)

    乔永平; 聂影

    2012-01-01

    目前森林资源产权市场仍处于起步阶段,存在着众多制约市场供求双方的因素.制约需求的因素包括森林资源产权制度不完善、森林资源风险防范机制不健全、林业融资难、林业比较利益低;制约供给的因素包括政策法规不完善、信息不完备、交易成本高、非农就业机会少、社会保障制度不健全等;通过市场中介间接影响供求的因素包括市场中介组织缺乏等.本研究给出了强化森林资源产权市场机制的对策建议.%Current forest resource property market is still at the initial stage and there are many restricting factors that affect both the supply and the demand. The factors restricting the demand are forest resource property systems being imperfect, forest resource risk prevention mechanism being incomplete, forestry financing being difficult, forestry comparative rate of profit being low and so on; the factors restricting the supply include concerning law and policies being imperfect, information being incomplete, trading cost being high, non-agricultural job chance being low, social security system being imperfect and so on; to make it worse, imperfect intermediary organization turns out to be one of the restricting factors affect both the supply and the demand. This research offers some countermeasure suggestions of strengthening forest resource property market mechanism.

  11. Interferon-α Subtypes in an Ex Vivo Model of Acute HIV-1 Infection: Expression, Potency and Effector Mechanisms.

    Directory of Open Access Journals (Sweden)

    Michael S Harper

    Full Text Available HIV-1 is transmitted primarily across mucosal surfaces and rapidly spreads within the intestinal mucosa during acute infection. The type I interferons (IFNs likely serve as a first line of defense, but the relative expression and antiviral properties of the 12 IFNα subtypes against HIV-1 infection of mucosal tissues remain unknown. Here, we evaluated the expression of all IFNα subtypes in HIV-1-exposed plasmacytoid dendritic cells by next-generation sequencing. We then determined the relative antiviral potency of each IFNα subtype ex vivo using the human intestinal Lamina Propria Aggregate Culture model. IFNα subtype transcripts from the centromeric half of the IFNA gene complex were highly expressed in pDCs following HIV-1 exposure. There was an inverse relationship between IFNA subtype expression and potency. IFNα8, IFNα6 and IFNα14 were the most potent in restricting HIV-1 infection. IFNα2, the clinically-approved subtype, and IFNα1 were both highly expressed but exhibited relatively weak antiviral activity. The relative potencies correlated with binding affinity to the type I IFN receptor and the induction levels of HIV-1 restriction factors Mx2 and Tetherin/BST-2 but not APOBEC3G, F and D. However, despite the lack of APOBEC3 transcriptional induction, the higher relative potency of IFNα8 and IFNα14 correlated with stronger inhibition of virion infectivity, which is linked to deaminase-independent APOBEC3 restriction activity. By contrast, both potent (IFNα8 and weak (IFNα1 subtypes significantly induced HIV-1 GG-to-AG hypermutation. The results unravel non-redundant functions of the IFNα subtypes against HIV-1 infection, with strong implications for HIV-1 mucosal immunity, viral evolution and IFNα-based functional cure strategies.

  12. Nutrient restrictive factors, nutrient absorption and accumulation of red kidney bean%红芸豆养分限制因子及养分吸收、积累和分配特征研究

    Institute of Scientific and Technical Information of China (English)

    韩彦龙; 晋凡生; 郑普山; 李晓平; 李洁; 李海金

    2016-01-01

    AbstractWith important economical and nutritional values, kidney bean (Phaseolus vuglaris) is one of the main grain crops in China. Recently, the planting area of red kidney bean has been gradually increasing in Shanxi Province, China. However, the nutrient absorption characteristics and limiting factors of kidney bean was still not very clear. Nitrogen (N), phosphorus (P) and potassium (K) are essential nutrients for plant growth, and knowledge on periodic uptake, accumulation and allocation of N, P and K in different organs of kidney bean is important to implement nutrient management practices to ensure its’ sustainable production. There were several studies on effect of the fertilization and nitrogen application on yield of kidney bean. However, few studies have investigated the nutrient accumulation and distribution characteristics of kidney bean. In this study, field experiment was conducted with different nutrient application (N absence, P absence, K absence, NPK application and no fertilizer) using the red kidney bean variety ‘British Red’ as the materials in 2014. The nutrient restrictive factors, dry matter accumulation and nutrient uptake and accumulation of red kidney bean were investigated. The samples of NPK application treatment at different growth stages were collected for determining dry matter and nutrient contents in different organs, to illustrate the law of nutrient absorption. This is beneficial to provide theoretical basis for rational fertilization and high yield cultivation of red kidney bean. The results showed that NPK application treatment significantly increased yield of red kidney bean compared to absence of N, P, or K and no fertilizer treatments. Compared to NPK application treatment, yields of N-, P- or K-absence decreased by 14.2%, 8.0% and 11.3%, respectively, which indicated that the order of nutrient restrictive factors of red kidney bean yield was N > K > P. The dry matter accumulation rate of red kidney bean increased

  13. Epigenetic regulation of caloric restriction in aging

    Directory of Open Access Journals (Sweden)

    Daniel Michael

    2011-08-01

    Full Text Available Abstract The molecular mechanisms of aging are the subject of much research and have facilitated potential interventions to delay aging and aging-related degenerative diseases in humans. The aging process is frequently affected by environmental factors, and caloric restriction is by far the most effective and established environmental manipulation for extending lifespan in various animal models. However, the precise mechanisms by which caloric restriction affects lifespan are still not clear. Epigenetic mechanisms have recently been recognized as major contributors to nutrition-related longevity and aging control. Two primary epigenetic codes, DNA methylation and histone modification, are believed to dynamically influence chromatin structure, resulting in expression changes of relevant genes. In this review, we assess the current advances in epigenetic regulation in response to caloric restriction and how this affects cellular senescence, aging and potential extension of a healthy lifespan in humans. Enhanced understanding of the important role of epigenetics in the control of the aging process through caloric restriction may lead to clinical advances in the prevention and therapy of human aging-associated diseases.

  14. Mechanisms of Salmonella Typhi Host Restriction.

    Science.gov (United States)

    Spanò, Stefania

    2016-01-01

    Salmonella enterica serovar Typhi (S. Typhi) is the cause of typhoid fever, a life-threatening bacterial infection that is very common in the developing world. Recent spread of antimicrobial resistant isolates of S. Typhi makes typhoid fever, a global public health risk. Despite being a common disease, still very little is known about the molecular mechanisms underlying typhoid fever and S. Typhi pathogenesis. In contrast to other Salmonellae, S. Typhi can only infect humans. The molecular bases of this human restriction are mostly unknown. Recent studies identified a novel pathway that contributes to S. Typhi human restriction and is required for killing S. Typhi in macrophages of nonsusceptible species. The small Rab GTPase Rab32 and its guanine nucleotide exchange factor BLOC-3 are the critical components of this pathway. These proteins were already well known as important regulators of intracellular membrane transport. In particular, they are central for the transport of enzymes that synthetize melanin in pigment cells. The recent findings that Rab32 and BLOC-3 are required for S. Typhi host restriction point out to a novel mechanism restricting the growth of bacterial pathogen, dependent on the transport of still unknown molecule(s) to the S. Typhi vacuole. The identification of this novel antimicrobial pathway constitutes a critical starting point to study molecular mechanisms killing bacterial pathogens and possibly identify novel antimicrobial molecules.

  15. An Investigation on the Restricting Factors of Teachers' Professional——Development in the west Rural Areas of Guangdong Province%农村教师专业发展阻抗因素分析——基于粤西地区农村中小学教师的调查

    Institute of Scientific and Technical Information of China (English)

    文雪; 廖诗艳

    2012-01-01

    It is significant to understand the restricting factors of teachers' professional development for advancing teachers' professional development.The study investigats the restricting factors of teachers' professional development in the west rural areas of Guangdong province.Results show that there are a lot of insufficiencies of sustaining factors,ensuring factors,technical factors,motiving factors in rural teachers' professional developing.The suggestion is to advance the teachers' professional development by improving social conditions,constructing systems,leading professional development,and inspiring individual motivity.%了解教师专业发展的阻抗因素对有效促进教师专业发展具有重要意义。本研究对粤西地区农村教师专业发展阻抗因素进行了调查,结果表明,农村教师的专业发展存在着支撑性因素、保障性因素、技术性因素、动机性因素等的缺失。需要有针对性地从环境改善、制度建设、专业引领、动机激发等方面来促进教师的专业发展。

  16. Repletion of TNFα or leptin in calorically restricted mice suppresses post-restriction hyperphagia

    Science.gov (United States)

    Hambly, Catherine; Duncan, Jacqueline S.; Archer, Zoë A.; Moar, Kim M.; Mercer, Julian G.; Speakman, John R.

    2012-01-01

    SUMMARY The causes of post-restriction hyperphagia (PRH) represent a target for drug-based therapies to prevent obesity. However, the factors causing PRH are poorly understood. We show that, in mice, the extent of PRH was independent of the time under restriction, but depended on its severity, suggesting that PRH was driven by signals from altered body composition. Signals related to fat mass were important drivers. Circulating levels of leptin and TNFα were significantly depleted following caloric restriction (CR). We experimentally repleted their levels to match those of controls, and found that in both treatment groups the level of PRH was significantly blunted. These data establish a role for TNFα and leptin in the non-pathological regulation of energy homeostasis. Signals from adipose tissue, including but not limited to leptin and TNFα, regulate PRH and might be targets for therapies that support people engaged in CR to reduce obesity. PMID:21954068

  17. Core-binding factor β increases the affinity between human Cullin 5 and HIV-1 Vif within an E3 ligase complex.

    Science.gov (United States)

    Salter, Jason D; Lippa, Geoffrey M; Belashov, Ivan A; Wedekind, Joseph E

    2012-11-06

    HIV-1 Vif masquerades as a receptor for a cellular E3 ligase harboring Elongin B, Elongin C, and Cullin 5 (EloB/C/Cul5) proteins that facilitate degradation of the antiretroviral factor APOBEC3G (A3G). This Vif-mediated activity requires human core-binding factor β (CBFβ) in contrast to cellular substrate receptors. We observed calorimetrically that Cul5 binds tighter to full-length Vif((1-192))/EloB/C/CBFβ (K(d) = 5 ± 2 nM) than to Vif((95-192))/EloB/C (K(d) = 327 ± 40 nM), which cannot bind CBFβ. A comparison of heat capacity changes supports a model in which CBFβ prestabilizes Vif((1-192)) relative to Vif((95-192)), consistent with a stronger interaction of Cul5 with Vif's C-terminal Zn(2+)-binding motif. An additional interface between Cul5 and an N-terminal region of Vif appears to be plausible, which has therapeutic design implications.

  18. Alteration of placental haemostatic mechanisms in idiopathic intrauterine growth restriction

    Directory of Open Access Journals (Sweden)

    Jaime Eduardo Bernal Villegas

    2012-08-01

    Full Text Available Intrauterine growth restriction is a complication of pregnancy with a high probability of perinatal morbidity and mortality. It appears tobe caused by abnormal development of placental vasculature. Haemostatic processes are important for the development of the placenta,and an imbalance between procoagulant and anticoagulant factors has been associated with risk of intrauterine growth restriction.Objective. To evaluate coagulation abnormalities in placenta of pregnancies complicated with idiopathic intrauterine growth restriction.Materials and methods. Five placentas from pregnancies with idiopathic intrauterine growth restriction were compared to 19 controls.We performed gross and histological examination of the placenta. Analysis was made of both mRNA expression by real-time PCRand protein by ELISA of tissue factor and thrombomodulin in placental tissue. Results. Results based on histological evaluation wereconsistent with an increased prothrombotic state in placentas from pregnancies with idiopathic intrauterine growth restriction, andthrombosis of chorionic vessels was the most important finding. The study showed an increased expression of tissue factor protein(p=0.0411 and an increase in the ratio of tissue factor/thrombomodulin mRNA (p=0.0411 and protein (p=0.0215 in placentas frompregnancies with idiopathic intrauterine growth restriction. There were no statistically significant differences neither between cases andcontrols in the mRNA levels of tissue factor or thrombomodulin nor at the protein level of thrombomodulin. Conclusion. Evidence ofalteration of local haemostatic mechanisms at the level of the placenta, including abnormal expression of tissue factor and tissue factor/thrombomodulin ratio, in pregnancies that occur with idiopathic intrauterine growth restriction is presented.

  19. Remarks on restricted Nevanlinna transforms

    CERN Document Server

    Jankowski, Lech

    2010-01-01

    The Nevanlinna transform K(z), of a measure and a real constant, plays an important role in the complex analysis and more recently in the free probability theory (boolean convolution). It is shown that its restriction k(it) (the restricted Nevanlinna transform) to the imaginary axis can be expressed as the Laplace transform of the Fourier transform (characteristic function) of the corresponding measure. Finally, a relation between the Voiculescu and the boolean convolution is indicated.

  20. Proteasomal degradation of TRIM5alpha during retrovirus restriction.

    Directory of Open Access Journals (Sweden)

    Christopher James Rold

    2008-05-01

    Full Text Available The host protein TRIM5alpha inhibits retroviral infection at an early post-penetration stage by targeting the incoming viral capsid. While the detailed mechanism of restriction remains unclear, recent studies have implicated the activity of cellular proteasomes in the restriction of retroviral reverse transcription imposed by TRIM5alpha. Here, we show that TRIM5alpha is rapidly degraded upon encounter of a restriction-susceptible retroviral core. Inoculation of TRIM5alpha-expressing human 293T cells with a saturating level of HIV-1 particles resulted in accelerated degradation of the HIV-1-restrictive rhesus macaque TRIM5alpha protein but not the nonrestrictive human TRIM5alpha protein. Exposure of cells to HIV-1 also destabilized the owl monkey restriction factor TRIMCyp; this was prevented by addition of the inhibitor cyclosporin A and was not observed with an HIV-1 virus containing a mutation in the capsid protein that relieves restriction by TRIMCyp IVHIV. Likewise, human TRIM5alpha was rapidly degraded upon encounter of the restriction-sensitive N-tropic murine leukemia virus (N-MLV but not the unrestricted B-MLV. Pretreatment of cells with proteasome inhibitors prevented the HIV-1-induced loss of both rhesus macaque TRIM5alpha and TRIMCyp proteins. We also detected degradation of endogenous TRIM5alpha in rhesus macaque cells following HIV-1 infection. We conclude that engagement of a restriction-sensitive retrovirus core results in TRIM5alpha degradation by a proteasome-dependent mechanism.

  1. A Brief Study on Factors Restricting State Treasury Cash Management in China and Countermeasures%浅谈制约我国国库现金管理的因素及对策

    Institute of Scientific and Technical Information of China (English)

    景涛

    2012-01-01

    The paper probes into the connotation and functions of the state treasury cash management and analyzes the major fac- tors which restrict the state treasury cash management. Some suggestions which strengthen the state treasury cash management are pro- posed such as constructing scientific budget management system, establishing developed government debt market and speeding up the construction of laws on state treasury.%本文探讨了国库现金管理的内涵及作用,分析了影响国库现金管理的主要因素。在此基础上,提出加强国库现金管理的相关建议:建立科学预算管理体系;建立发达的国债市场;加快国库法律制度建设等。

  2. Molecular motion in restricted geometries

    Indian Academy of Sciences (India)

    Siddharth Gautam; S Mitra; R Mukhopadhyay

    2008-10-01

    Molecular dynamics in restricted geometries is known to exhibit anomalous behaviour. Diffusion, translational or rotational, of molecules is altered significantly on confinement in restricted geometries. Quasielastic neutron scattering (QENS) offers a unique possibility of studying molecular motion in such systems. Both time scales involved in the motion and the geometry of motion can be studied using QENS. Molecular dynamics (MD) simulation not only provides insight into the details of the different types of motion possible but also does not suffer limitations of the experimental set-up. Here we report the effect of confinement on molecular dynamics in various restricted geometries as studied by QENS and MD simulations: An example where the QENS technique provided direct evidence of phase transition associated with change in the dynamical behaviour of the molecules is also discussed.

  3. Legal restrictions and Investment Growth

    NARCIS (Netherlands)

    Lensink, B.W.; Scholtens, B.

    2007-01-01

    We analyze the impact of legal restrictions on investment growth at the firm level. With the help of a unique firm-level survey database, we analyze whether firm investments are related to the efficiency and quality of the judiciary. Furthermore, we analyze whether the investment behavior of large a

  4. Legal restrictions and investment growth

    NARCIS (Netherlands)

    Lensink, B.W.; Scholtens, B.

    2007-01-01

    We analyze the impact of legal restrictions on investment growth at the firm level. With the help of a unique firm-level survey database, we analyze whether firm investments are related to the efficiency and quality of the judiciary, Furthermore, we analyze whether the investment behavior of large a

  5. Restrictive dermopathy and fetal behaviour

    NARCIS (Netherlands)

    Mulder, EJH; Beemer, FA; Stoutenbeek, P

    2001-01-01

    We report three siblings from consecutive pregnancies affected with restrictive dermopathy (RD). During the second pregnancy, fetal behavioural development and growth were studied extensively using ultrasound at 1-4 week intervals. Dramatic and sudden changes occurred in fetal body movements and gro

  6. Restricted Morgan’s problem

    Institute of Scientific and Technical Information of China (English)

    陈树中; 曹立

    1996-01-01

    A new list of regular feedback invariant integers called right independent orders is introduced.That the restricted Morgan’s problem is equivalent to a kind of nonlinear algebraic equations is proved and the condition that the nonlinear algebraic equations degenerate into linear algebraic equations is given.

  7. Physiogenomic analysis of weight loss induced by dietary carbohydrate restriction

    Directory of Open Access Journals (Sweden)

    Wood Richard J

    2006-05-01

    Full Text Available Abstract Background Diets that restrict carbohydrate (CHO have proven to be a successful dietary treatment of obesity for many people, but the degree of weight loss varies across individuals. The extent to which genetic factors associate with the magnitude of weight loss induced by CHO restriction is unknown. We examined associations among polymorphisms in candidate genes and weight loss in order to understand the physiological factors influencing body weight responses to CHO restriction. Methods We screened for genetic associations with weight loss in 86 healthy adults who were instructed to restrict CHO to a level that induced a small level of ketosis (CHO ~10% of total energy. A total of 27 single nucleotide polymorphisms (SNPs were selected from 15 candidate genes involved in fat digestion/metabolism, intracellular glucose metabolism, lipoprotein remodeling, and appetite regulation. Multiple linear regression was used to rank the SNPs according to probability of association, and the most significant associations were analyzed in greater detail. Results Mean weight loss was 6.4 kg. SNPs in the gastric lipase (LIPF, hepatic glycogen synthase (GYS2, cholesteryl ester transfer protein (CETP and galanin (GAL genes were significantly associated with weight loss. Conclusion A strong association between weight loss induced by dietary CHO restriction and variability in genes regulating fat digestion, hepatic glucose metabolism, intravascular lipoprotein remodeling, and appetite were detected. These discoveries could provide clues to important physiologic adaptations underlying the body mass response to CHO restriction.

  8. 30 CFR 56.11008 - Restricted clearance.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Restricted clearance. 56.11008 Section 56.11008 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE... Restricted clearance. Where restricted clearance creates a hazard to persons, the restricted clearance...

  9. 30 CFR 57.11008 - Restricted clearance.

    Science.gov (United States)

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Restricted clearance. 57.11008 Section 57.11008... Escapeways Travelways-Surface and Underground § 57.11008 Restricted clearance. Where restricted clearance creates a hazard to persons, the restricted clearance shall be conspicuously marked....

  10. 甘肃省少数民族地区包容性增长制约因素分析——基于“十二五”的历史方位%Analysis about restrictive Factors in Minority Area of GanSu's Inclusive Growth --Based on the Historical Position of the Period from the Year 2011 to 2015

    Institute of Scientific and Technical Information of China (English)

    张克政

    2012-01-01

    包容性增长是“十二五”时期甘肃省少数民族地区发展面临的重大课题。经济基础薄弱、发展任务繁重、自然条件恶劣、地理区住劣势明显、基础设施落后、社会事业发展滞后、人才资源匮乏、制度不完善、社会不公是制约“十二五”时期少数民族地区包容性增长的主要因素。深入分析少数民族地区包容性增长的制约因素,是推动少数民族地区包容性增长的前提。%Inclusive growth is a great subject to minority area of GanSu in the period of the year 2011 to 2015. The unsubstantial economic foundation, heavy development task, bad natural conditions, evident geographical location disadvantages, behindhand infrastructure, hysteretic development of social undertakings, deficient resources of human talents, ineompletcd system and social injustice are major restrictive factors which will restrict minority area of Gansu's inclusive growth in the period from the year 2011 to 2015. In-depth analysis of the restrictive factors about minority area of GanSu's inclusive growth is the precondition of pushing forward minority area of GanSu's inclusive growth.

  11. 制约拓展训练课程在高校开设的因素分析及解决对策%On the Restrictive Factors of Outward Bound Training Course Development in Universities and Its Countermeasures

    Institute of Scientific and Technical Information of China (English)

    黄观

    2012-01-01

    In recent years, outward bound training has been brought into the curriculum system by many colleges as a new course, but there are some problems such as the unsound curriculum system, contents of the course without specific aim, the low-teaching level and space facilities posing some safety hazards which seriously restrict the development of outward bound training in universities. For the above problems, this paper proposes appropriate countermeasures, aiming to offer some reference suggestions for the development and extension of outward bound training courses in Chinese universities.%近年来拓展训练作为一门新兴课程被很多高校纳入课程体系之中,但课程体系不健全、课程的内容针对性不强、课程师资薄弱、场地设施存在安全隐患等问题严重制约着其在高校的开展。本文针对以上问题提出相应对策,旨在为我国高校拓展训练课程开展和推广提供一些参考。

  12. Neuron-restrictive silencer factor (NRSF) represses cocaine- and amphetamine-regulated transcript (CART) transcription and antagonizes cAMP-response element-binding protein signaling through a dual NRSE mechanism.

    Science.gov (United States)

    Zhang, Jing; Wang, Sihan; Yuan, Lin; Yang, Yinxiang; Zhang, Bowen; Liu, Qingbin; Chen, Lin; Yue, Wen; Li, Yanhua; Pei, Xuetao

    2012-12-14

    Cocaine- and amphetamine-regulated transcript (CART) peptide plays a pivotal role in neuroprotection against stroke-related brain injury. However, the regulatory mechanism on CART transcription, especially the repression mechanism, is not fully understood. Here, we show that the transcriptional repressor neuron-restrictive silencer elements (NRSF, also known as REST) represses CART expression through direct binding to two NRSF-binding elements (NRSEs) in the CART promoter and intron 1 (named pNRSE and iNRSE, respectively). EMSA show that NRSF binds to pNRSE and iNRSE directly in vitro. ChIP assays show that NRSF recruits differential co-repressor complexes including CoREST and HDAC1 to these NRSEs. The presence of both NRSEs is required for efficient repression of CART transcription as indicated by reporter gene assays. NRSF overexpression antagonizes forskolin-mediated up-regulation of CART mRNA and protein. Ischemia insult triggered by oxygen-glucose deprivation (OGD) enhances NRSF mRNA levels and then NRSF antagonizes the CREB signaling on CART activation, leading to augmented cell death. Depletion of NRSF in combination with forskolin treatment increases neuronal survival after ischemic insult. These findings reveal a novel dual NRSE mechanism by which NRSF represses CART expression and suggest that NRSF may serve as a therapeutic target for stroke treatment.

  13. 高原地区胎盘VEGF在胎儿生长受限和巨大儿中的表达及意义%Expression of plateau area placenta vascular endothelial growth factor iIn fetal growth restriction And Great children and its significance

    Institute of Scientific and Technical Information of China (English)

    陈玉芬

    2012-01-01

    目的 血管内皮生长因子(VEGF)是一种对血管内皮细胞有特异高效的促有丝分裂因子,通过检测血管内皮生长因子在胎盘母面和子面的水平,探索胎儿生长受限和巨大儿的发病因素和发生的机制.方法 随机选择2010年1月至2011年2月在青海省妇女儿童医院足月分娩的足月小样儿(体重<2 500g的新生儿)50例产妇为宫内发育受限组,选择同期分娩体重≥4 000g新生儿50例产妇为巨大儿组;采用免疫组化链霉菌抗生物素蛋白-过氧化酶连接法(SP法)检测巨大儿(对照组)和胎儿生长受限患者(IUGR组)胎盘组织中VEGF的表达;巨大儿和IUGR组均为初产妇,两组孕妇年龄、孕周及体质量差异无显著性.结果 胎儿生长受限患者胎盘组织中VEGF阳性表达率低于巨大儿组,两者差异有统计学意义(P<0.05).结论 IUGR患者胎盘VEGF水平下降,可能是胎儿生长受限发病机理中的一个重要因素.%Objective Vascular endothelial growth factor is a vascular endothelial cell - specific and efficient mitogenic factor,by vascular endothelial growth factor in placenta parent surface and sub - surface level,to explore fetal growth restriction and a huge childrens risk factors and the mechanisms. Methods Randomly selected from January 2010 to February 2011 in our hospital term delivery of full - term small for gestational age ( body weight < 2500g neonates ) 50 cases of maternal intrauterine growth restriction group,select the new year birth weight ≥4000g children 50 cases of maternal child for the great group; Immunohistochemical streptavidin - biotin - peroxidase method (SP method) to detect a huge children ( control group) and patients with fetal growth restriction (IUGR group) placental tissue VEGF expression; Great children and the IUGR group were primipara,two groups of maternal age,gestational age and body mass difference was not statistically significant. Results Fetal growth restriction in placental

  14. 双重的约束:女性科技人才成长的制约因素分析%Double Constraints: Analysis of Restricting Factors in Female Talents' Growth in Science and Technology

    Institute of Scientific and Technical Information of China (English)

    袁志群

    2011-01-01

    近年来,我国的科技事业发展迅速。然而,科技人才队伍中的女性科技人才却发展较为缓慢,原因在于女性科技人才的发展受到了公私领域的双重约束即私人领域的家庭劳动、家庭决策、家庭教育投资以及公共领域的科技人才准入、培育和评价机制制约了女性科技人才的发展。在这种双重约束下,女性科技人才只能在具有性别排斥的科技领域中充当幕后支撑力量,相反,男性则在科技人才发展中占主导优势,成为主要的受惠群体。%The science and technology in China has developed rapidly in recent years. However, the development of female talents in science and technological is relatively slow. The admittance mechanism, cultivation mechanism, evalua tion mechanism in public domain and the housework, the family decision-making, the family education investment in the private sector restrict their development. As a result, female talents can just be the supporting power on backstage in the field of science and technology in which there is a gender rejection, on the contrary, the male talents dominate and benefit.

  15. HIV-related travel restrictions: trends and country characteristics

    Directory of Open Access Journals (Sweden)

    Felicia Chang

    2013-06-01

    a finding that is relevant to migrant populations and travel medicine providers alike. Despite international pressure to remove travel restrictions, many countries continue to implement these restrictions for HIV-positive individuals on entry and stay. Since 2010, the United States and China have engaged in high profile removals. This may be indicative of an increasing trend, facilitated by various factors, including international advocacy and the setting of a UNAIDS goal to halve the number of countries with restrictions by 2015.

  16. APOBEC3G-induced hypermutation of human immunodeficiency virus type-1 is typically a discrete "all or nothing" phenomenon

    DEFF Research Database (Denmark)

    Armitage, Andrew E; Deforche, Koen; Chang, Chih-Hao;

    2012-01-01

    are ∼10-fold lower than the lowest observed hypermutation levels in vitro and in vivo. Our results suggest that even a single incorporated hA3G-unit is likely to cause extensive and inactivating levels of HIV hypermutation and that hypermutation therefore is typically a discrete "all or nothing...

  17. Electromagnetic Fields Restrictions and Approximation

    CERN Document Server

    Katsenelenbaum, Boris Z

    2003-01-01

    The fields scattered by metallic bodies or radiated by some types of antennas are created by the surfaces currents and therefore they are subject to some restrictions. The book is the first one where the properties of these fields are investigated in details. The properties have the important significance for the antenna synthesis, body shape reconstruction and other diffraction problems. The material of the book lies in the meetingpoint of the antenna theory, highfrequency electrodynamics and inverse scattering problems. The author is an internationally renowned investigator in the field of e

  18. Avoidant/Restrictive Food Intake Disorder

    Science.gov (United States)

    ... for the Professional Version Eating Disorders Definition of Eating Disorders Anorexia Nervosa Avoidant/Restrictive Food Intake Disorder Binge Eating ... about what they eat. Eating Disorders Definition of Eating Disorders Anorexia Nervosa Avoidant/Restrictive Food Intake Disorder Binge Eating ...

  19. Study on the Main Restricting Factors and Countermeasures of the Development of the Disabled Fitness in Anhui Province%制约安徽省残疾人健身体育开展的主要因素及对策研究

    Institute of Scientific and Technical Information of China (English)

    陈华; 牛伟; 郝薇薇

    2013-01-01

    Definition of the disabled fitness and main factors restricting the development of Anhui Province disabled sports and fitness are analyzed; According to the relevant state policies, laws and regulations and the basic functions of sports, some suggestions and countermeasures of carring out disabled sports in Anhui Province are put forward.%  讨论了残疾人健身体育的涵义、制约安徽省残疾人健身体育活动开展的主要因素等问题。依据国家相关政策、法律、法规和制度及体育基本功能,提出了安徽省残疾人健身体育活动开展的建议与对策。

  20. 7 CFR 982.14 - Restricted hazelnuts.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 8 2010-01-01 2010-01-01 false Restricted hazelnuts. 982.14 Section 982.14... Agreements and Orders; Fruits, Vegetables, Nuts), DEPARTMENT OF AGRICULTURE HAZELNUTS GROWN IN OREGON AND WASHINGTON Order Regulating Handling Definitions § 982.14 Restricted hazelnuts. Restricted hazelnuts...

  1. Problem-Solving Test: Restriction Endonuclease Mapping

    Science.gov (United States)

    Szeberenyi, Jozsef

    2011-01-01

    The term "restriction endonuclease mapping" covers a number of related techniques used to identify specific restriction enzyme recognition sites on small DNA molecules. A method for restriction endonuclease mapping of a 1,000-basepair (bp)-long DNA molecule is described in the fictitious experiment of this test. The most important fact needed to…

  2. Restriction Enzyme Mapping: A Simple Student Practical.

    Science.gov (United States)

    Higgins, Stephen J.; And Others

    1990-01-01

    An experiment that uses the recombinant plasmid pX1108 to illustrate restriction mapping is described. The experiment involves three restriction enzymes and employs single and double restriction enzyme digestions. A list of needed materials, procedures, safety precautions, results, and discussion are included. (KR)

  3. Restrictive Imputation of Incomplete Survey Data

    NARCIS (Netherlands)

    Vink, G.

    2015-01-01

    This dissertation focuses on finding plausible imputations when there is some restriction posed on the imputation model. In these restrictive situations, current imputation methodology does not lead to satisfactory imputations. The restrictions, and the resulting missing data problems are real-life

  4. 29 CFR 18.56 - Restricted access.

    Science.gov (United States)

    2010-07-01

    ... 29 Labor 1 2010-07-01 2010-07-01 true Restricted access. 18.56 Section 18.56 Labor Office of the... ADMINISTRATIVE LAW JUDGES General § 18.56 Restricted access. On his or her own motion, or on the motion of any party, the administrative law judge may direct that there be a restricted access portion of the...

  5. 28 CFR 68.51 - Restricted access.

    Science.gov (United States)

    2010-07-01

    ... 28 Judicial Administration 2 2010-07-01 2010-07-01 false Restricted access. 68.51 Section 68.51... ALIENS, UNFAIR IMMIGRATION-RELATED EMPLOYMENT PRACTICES, AND DOCUMENT FRAUD § 68.51 Restricted access. On... be a restricted access portion of the record to contain any material in the record to which...

  6. 47 CFR 1.1208 - Restricted proceedings.

    Science.gov (United States)

    2010-10-01

    ... 47 Telecommunication 1 2010-10-01 2010-10-01 false Restricted proceedings. 1.1208 Section 1.1208... Restricted Proceedings § 1.1208 Restricted proceedings. Unless otherwise provided by the Commission or its... in all proceedings not listed as exempt in § 1.1204(b) or permit-but-disclose in § 1.1206(a) of...

  7. Querying Schemas With Access Restrictions

    CERN Document Server

    Benedikt, Michael; Ley, Clemens

    2012-01-01

    We study verification of systems whose transitions consist of accesses to a Web-based data-source. An access is a lookup on a relation within a relational database, fixing values for a set of positions in the relation. For example, a transition can represent access to a Web form, where the user is restricted to filling in values for a particular set of fields. We look at verifying properties of a schema describing the possible accesses of such a system. We present a language where one can describe the properties of an access path, and also specify additional restrictions on accesses that are enforced by the schema. Our main property language, AccLTL, is based on a first-order extension of linear-time temporal logic, interpreting access paths as sequences of relational structures. We also present a lower-level automaton model, Aautomata, which AccLTL specifications can compile into. We show that AccLTL and A-automata can express static analysis problems related to "querying with limited access patterns" that h...

  8. On Changes of the City Size and Restricting Factors of Cities in Southern Xinjiang In Modern Period%近代南疆城市规模的变化与制约因素论析

    Institute of Scientific and Technical Information of China (English)

    何一民

    2014-01-01

    清代前中期,南疆城市发展比北疆城市缓慢。晚清时期,随着外国资本主义的渗入、新疆建省和清政府推行一系列改革,南疆城市获得了较大发展,呈现出以喀什、和阗为中心的南疆西南城市体系的雏形和以阿克苏为中心的南疆东北城市体系的雏形。民国时期,随着新疆人口的增加和经济的发展,南疆城市人口和城市空间也都有所扩大和变化,尤其是南疆东北部地区的城市变化较为突出。虽然南疆城市在此一时期有所发展,但数量仍然不多,人口规模和空间规模都普遍较小。制约南疆城市发展的因素,除了自然环境脆弱、经济不发达、交通运输落后外,社会动乱、政局变化以及民族、宗教等因素的制约也不可忽略。%In early and middle Qing dynasty, Southern Xinjiang developed slower than Northern Xin-jiang. In late Qing Dynasty, with the infiltration of foreign capitalism, the establishment of Xinjiang prov-ince, and a series of reform measures implemented by the Qing government, the southern Xinjiang cities obtained considerable development. Kashgar, Hetian and Aksu city become the centers of southern Xin-jiang’ s urban system. During the period of the Republic of China, with the increase of population in Xin-jiang and the development of economy, southern Xinjiang urban population and urban space were wid-ened and changed, especially in the northeast region of southern Xinjiang. Although the southern Xin-jiang city achieved a certain degree of development in this period, the cities are not of great number while population and spatial scale were generally small. There were other factors which hindered the urban de-velopment of cities in southern Xinjiang, such as natural geographical environment, undeveloped econo-my, inconvenient transportation, social turmoil, political change, ethnic and religious factors.

  9. Reversal of HIV drug resistance and novel strategies to curb HIV infection: the viral infectivity factor Vif as a target and tool of therapy.

    Science.gov (United States)

    Mezei, M; Minarovits, J

    2006-07-01

    Due to the high genetic variability of human immunodeficiency virus (HIV), treatment of AIDS (acquired immunodeficiency syndrome) patients with inhibitors of reverse trancriptase (RT) and drugs blocking the viral protease regularly results in the accumulation of drug resistant HIV variants and treatment failure. The sensitivity of clinically derived resistant HIV-1 strains to nucleotide RT inhibitors could be restored, however, in several laboratories by pharmacological depletion of the appropriate endogenous deoxynucleotide triphosphate (dNTP), and such a manipulation (induction of dCTP pool imbalance during reverse transcription in the presence of a non-nucleoside RT inhibitor) altered the mutation spectrum of the HIV-1 genome, resulting in a lower level of HIV resistance to certain drugs. The cytoplasmic single-stranded DNA cytidine deaminases APOBEC3G and APOBEC3F block HIV replication by introducing premature stop codons into the viral genome. We suggest that the resulting crippled, defective HIV (dHIV) variants could interfere with replication of "wild type" viruses and curbe disese progression in long term non-progressor individuals. Vif, an accessory protein encoded by HIV, counteracts APOBEC3G/F action. We speculate that small molecule inhibitors of Vif could permit lethal or sublethal mutagenesis of HIV genomes. We suggest that an artificial dHIV construct carrying a mutated vif gene (coding for a Vif protein unable to block APOBEC3G/F) could have a therapeutic effect as well in HIV infected individuals and AIDS patients.

  10. 低出生体重早产儿宫外发育迟缓的相关因素分析%Related factors of extrauterine growth restriction in low birth weight preterm children

    Institute of Scientific and Technical Information of China (English)

    廖文君

    2014-01-01

    目的:探讨胎龄≤32周低出生体重早产儿宫外发育迟缓(EUGR)发生率及其相关影响因素。方法纳入126例胎龄≤32周低出生体重早产儿,记录胎龄(超声或出生时成熟度分析数据)、出生时体重、身长、头围、性别、是否低于胎龄儿、是否存在呼吸窘迫综合征、最大生理性体重减少率、恢复出生体重的天数、起始肠内喂养时间、完全肠内喂养时间(每天奶量>100 ml/kg·d),37~42周时测定早产儿体重、身长、头围,以体重、身长和头围计,分析EUGR发生率、其危险因素以及适于胎龄儿(AGA)和低于胎龄儿(SGA) EUGR发生率。结果 EUGR组胎龄、出生体重、出生身长、出生头围均低于非EUGR组(均P100 ml/kg·d) were recorded. During 37~42 weeks, weight, length, head circumference, body weight, length and head circumference of premature children were measured. Incidence of EUGR and risk factors, and incidences of EUGR in appropriate for gestational age children (AGA) and small for gestational age children (SGA) were analyzed. Results The gestational age, birth weight, birth length, and head circumference at birth of EUGR group were lower than those of the non-EUGR group (all P<0.01), while the rate of weight loss (%), time to regain birth weight, time for starting enteral feeding and giving full enteral feeding were greater than those of non-EUGR group (all P<0.01). The proportion of SGA was significantly greater than that of non-EUGR group (all P<0.05). Based on weight, length, head circumference, incidences of EUGR in all newborns were 47.6%, 39.7%and 4.8%. Toatally, extrauterine growth retardation rate of SGA was significantly higher than that of AGA (all P<0.01).Gestational age, birth weight, recovery time, and time for full enteral feeding were closely related with EUGR. Conclusion Gestation-al age, intrauterine growth retardation, poor nutritional intake and RDS are still the risk factors of EUGR in premature

  11. 医院临床药学服务能力的制约因素及对策探讨%Restricted factors of hospital clinical pharmaceutical care capability and discussion of improved countermeasures

    Institute of Scientific and Technical Information of China (English)

    孙艳; 黄翠丽; 张明华; 李德东; 王沭

    2016-01-01

    Objective:To explore effective measures for improving pharmaceutical care capability of the hospital .Methods:A questionnaire survey was made on the clinical physicians ,nurses ,dispensary pharmacists and clinical pharmacists in the 65 tertiary hospitals across the country .The contents of the survey included the scope of hospital pharmaceutical care ,the mode of clinical pharmaceutical care ,the comprehensive capability of pharmacist pharmaceutical care ,as well as the rate of recognition by medical personnel of the hospital .Then ,all the obtained data were summarized and analyzed .Results and Conclusion:Sur‐vey results indicated that the main contents of clinical pharmaceutical care by pharmacists included the review of medical orders , medication consultation of outpatients ,medication education ,drug dispensing and so on .The main factors affecting further de‐velopment of clinical pharmacists were 4 external and 6 internal factors .In view of higher demands on pharmaceutical care by clinical medical personnel ,pharmacists should improve their professional quality to satisfy increasing clinical needs .With this in view ,the pharmacy department should further improve the professional quality of clinical pharmacists and establish the phar‐maceutical care platform suitable to the situation in China ,so as to establish the new pharmaceutical care mode with the patient as the center and rational medication as the core ,and ultimately enhance the pharmaceutical care capability of pharmacists .%目的:探索提高医院药师药学服务能力的有效举措。方法:在全国范围内对65家三级甲等医院医师、护士、药房药师和临床药师进行问卷调研,调研内容主要包括医院药学工作内容、临床药学服务工作方式、药师药学服务综合能力及医护人员对药师认知度等方面,并对采集的数据进行汇总和分析。结果和结论:调研结果表明,药师在医院从事的药学服务工作

  12. On Restricting Factors and Countermeasures of the Development of Carrageenan%我国卡拉胶生产发展制约因素及其对策的探讨

    Institute of Scientific and Technical Information of China (English)

    郭善慧; 关键

    2014-01-01

    卡拉胶用作天然食品添加剂已有多年的历史,它是一种无毒而又不能被人体消化的植物纤维,用途十分广泛。国外的卡拉胶商业性生产是从20世纪20年代开始的。我国则从1985年开始生产商业用卡拉胶,其中80%用于食品或与食品有关的工业。随着食品、医疗等行业发展,国内外市场对卡拉胶需求不断扩大,但卡拉胶行业在蓬勃发展的同时遇到瓶颈。本文主要通过对卡拉胶生产发展制约因素的研究,以探讨破解瓶颈的方法和策略。%Carrageenan is used as a natural food additive has a long history, it is the plant fiber which is a non-toxic and can not be digested by, use isvery extensive. Carrageenan demand has continued to expand, but in recent years the development of carrageenan bottleneck of highlights. In this paper , through the research on the development of carrageenan production factors, to explore the methods and strategies of breaking the bottleneck.

  13. Restricting Factors and Countermeasures on College Students ’ Political Participation through Network%大学生网络政治参与的制约因素及对策研究

    Institute of Scientific and Technical Information of China (English)

    丁鸿睿

    2014-01-01

    政治参与渠道的网络化为大学生提供了更加便利的条件,大学生网络政治参与已日益成为中国政治生活里不容忽视的一股力量。综观目前的发展状况,大学生在网络政治参与中受到社交网络肆意膨胀、政治参与心态不成熟、参与动机趋向功利化等方面因素的影响。面对现实,政府应完善网络立法和监管,高校应加强大学生思想政治教育,大学生要提升网络政治参与水平。%Political participation channels of the network to provide a more convenient condition for college students, college students’ network political participation has increasingly become a force to be reckoned with in the China’s political life. Throughout the current status of the development of college students in the network political participation by social networks is wanton expansion, political participation, mentality is not mature, and participation motivation tend to be utilitarian factors, the government should face it improving the Internet legislation and regulation, should strengthen the ideological and political education in colleges and universities, college students to enhance the level of network political participation.

  14. Observability in electric power networks: a method of ways of factorization in state estimation with equality restrictions; Observabilidade em redes de energia: um metodo de caminhos de fatoracao em estimacao de estado com restricoes de igualdade

    Energy Technology Data Exchange (ETDEWEB)

    Vicentino, Flavio Antonio

    1997-07-01

    A theory of network observability that mixes graph concepts and factorization of the gain matrix G has been recently developed. It uses data already available in Power System Operating Centers. That theory is easy to understand and implement and does not require subroutines other than the ones used in static state estimation. However, this new theory has been implemented only for the case of state estimation in Normal Equation Formulation (N E). However, the N E Method presents some inherent numerical difficulties. Such numerical difficulties are usually related to the disparity in the measurements weights (high values for zero-injections measurements and low values for pseudo-measurements) and the presence of short lines in the network, as well. In order to solve such numerical difficulties, new methods have come up, such as: Normal Equation Method with Equality Constraints (N E/C), where Lagrange's Multiplier Method can be applied to minimize a function while satisfying a set of constraints; Hachtel's Method, which is formulated the same way as N E/C Method, although an equation of residual vector is introduced in solution process; Hybrid Method, which is a general formulation behaving as the N E/C Method at one extreme, and as Hachtel's Method at the other. Thus, the aim of this work is to treat the adaptation of the network observability Method by using path graphs, with the state estimation in the form of a minimization problem with equality constraints. As the Hybrid Method is a generalization form of the state estimator with constraints, this formulation is used to develop the proposed theory. Extreme case (as the pure Hachtel's Method) are also considered. (author)

  15. Paternally Inherited IGF2 Mutation and Growth Restriction.

    Science.gov (United States)

    Begemann, Matthias; Zirn, Birgit; Santen, Gijs; Wirthgen, Elisa; Soellner, Lukas; Büttel, Hans-Martin; Schweizer, Roland; van Workum, Wilbert; Binder, Gerhard; Eggermann, Thomas

    2015-07-23

    In humans, mutations in IGF1 or IGF1R cause intrauterine and postnatal growth restriction; however, data on mutations in IGF2, encoding insulin-like growth factor (IGF) II, are lacking. We report an IGF2 variant (c.191C→A, p.Ser64Ter) with evidence of pathogenicity in a multigenerational family with four members who have growth restriction. The phenotype affects only family members who have inherited the variant through paternal transmission, a finding that is consistent with the maternal imprinting status of IGF2. The severe growth restriction in affected family members suggests that IGF-II affects postnatal growth in addition to prenatal growth. Furthermore, the dysmorphic features of affected family members are consistent with a role of deficient IGF-II levels in the cause of the Silver-Russell syndrome. (Funded by Bundesministerium für Bildung und Forschung and the European Union.).

  16. Gentile statistics and restricted partitions

    Indian Academy of Sciences (India)

    C S Srivatsan; M V N Murthy; R K Bhaduri

    2006-03-01

    In a recent paper (Tran et al, Ann. Phys. 311, 204 (2004)), some asymptotic number theoretical results on the partitioning of an integer were derived exploiting its connection to the quantum density of states of a many-particle system. We generalise these results to obtain an asymptotic formula for the restricted or coloured partitions $p_{k}^{s} (n)$, which is the number of partitions of an integer into the summand of th powers of integers such that each power of a given integer may occur utmost times. While the method is not rigorous, it reproduces the well-known asymptotic results for = 1 apart from yielding more general results for arbitrary values of .

  17. Neurodevelopment after fetal growth restriction.

    Science.gov (United States)

    Baschat, Ahmet A

    2014-01-01

    Fetal growth restriction (FGR) can emerge as a complication of placental dysfunction and increases the risk for neurodevelopmental delay. Marked elevations of umbilical artery (UA) Doppler resistance that set the stage for cardiovascular and biophysical deterioration with subsequent preterm birth characterize early-onset FGR. Minimal, or absent UA Doppler abnormalities and isolated cerebral Doppler changes with subtle deterioration and a high risk for unanticipated term stillbirth are characteristic for late-onset FGR. Nutritional deficiency manifested in lagging head growth is the most powerful predictor of developmental delay in all forms of FGR. Extremes of blood flow resistance and cardiovascular deterioration, prematurity and intracranial hemorrhage increase the risks for psychomotor delay and cerebral palsy. In late-onset FGR, regional cerebral vascular redistribution correlates with abnormal behavioral domains. Irrespective of the phenotype of FGR, prenatal tests that provide precise and independent stratification of risks for adverse neurodevelopment have yet to be determined.

  18. INTERPOLATION WITH RESTRICTED ARC LENGTH

    Institute of Scientific and Technical Information of China (English)

    Petar Petrov

    2003-01-01

    For given data (ti,yi), I= 0,1,…,n,0 = t0 <t1 <…<tn = 1we study constrained interpolation problem of Favard type inf{‖f"‖∞|f∈W2∞[0,1],f(ti)=yi,i=0,…,n,l(f;[0,1])≤l0}, wherel(f";[0,1])=∫1 0 / 1+f'2(x)dx is the arc length off in [0,1]. We prove the existence of a solution f* of the above problem, that is a quadratic spline with a second derivative f"* , which coincides with one of the constants - ‖f"*‖∞,0,‖f"*‖∞ between every two consecutive knots. Thus, we extend a result ofKarlin concerning Favard problem, to the case of restricted length interpolation.

  19. Stillbirth and fetal growth restriction.

    Science.gov (United States)

    Bukowski, Radek

    2010-09-01

    The association between stillbirth and fetal growth restriction is strong and supported by a large body of evidence and clinically employed for the stillbirth prediction. However, although assessment of fetal growth is a basis of clinical practice, it is not trivial. Essentially, fetal growth is a result of the genetic growth potential of the fetus and placental function. The growth potential is the driving force of fetal growth, whereas the placenta as the sole source of nutrients and oxygen might become the rate limiting element of fetal growth if its function is impaired. Thus, placental dysfunction may prevent the fetus from reaching its full genetically determined growth potential. In this sense fetal growth and its aberration provides an insight into placental function. Fetal growth is a proxy for the test of the effectiveness of placenta, whose function is otherwise obscured during pregnancy.

  20. An Infinite Restricted Boltzmann Machine.

    Science.gov (United States)

    Côté, Marc-Alexandre; Larochelle, Hugo

    2016-07-01

    We present a mathematical construction for the restricted Boltzmann machine (RBM) that does not require specifying the number of hidden units. In fact, the hidden layer size is adaptive and can grow during training. This is obtained by first extending the RBM to be sensitive to the ordering of its hidden units. Then, with a carefully chosen definition of the energy function, we show that the limit of infinitely many hidden units is well defined. As with RBM, approximate maximum likelihood training can be performed, resulting in an algorithm that naturally and adaptively adds trained hidden units during learning. We empirically study the behavior of this infinite RBM, showing that its performance is competitive to that of the RBM, while not requiring the tuning of a hidden layer size.

  1. 10 CFR 1045.16 - Criteria for evaluation of restricted data and formerly restricted data information.

    Science.gov (United States)

    2010-01-01

    ... § 1045.16 Criteria for evaluation of restricted data and formerly restricted data information. (a) The... 10 Energy 4 2010-01-01 2010-01-01 false Criteria for evaluation of restricted data and formerly restricted data information. 1045.16 Section 1045.16 Energy DEPARTMENT OF ENERGY (GENERAL PROVISIONS)...

  2. Restricted Interval Valued Neutrosophic Sets and Restricted Interval Valued Neutrosophic Topological Spaces

    Directory of Open Access Journals (Sweden)

    Anjan Mukherjee

    2016-08-01

    Full Text Available In this paper we introduce the concept of restricted interval valued neutrosophic sets (RIVNS in short. Some basic operations and properties of RIVNS are discussed. The concept of restricted interval valued neutrosophic topology is also introduced together with restricted interval valued neutrosophic finer and restricted interval valued neutrosophic coarser topology. We also define restricted interval valued neutrosophic interior and closer of a restricted interval valued neutrosophic set. Some theorems and examples are cites. Restricted interval valued neutrosophic subspace topology is also studied.

  3. Isocitrate ameliorates anemia by suppressing the erythroid iron restriction response.

    Science.gov (United States)

    Richardson, Chanté L; Delehanty, Lorrie L; Bullock, Grant C; Rival, Claudia M; Tung, Kenneth S; Kimpel, Donald L; Gardenghi, Sara; Rivella, Stefano; Goldfarb, Adam N

    2013-08-01

    The unique sensitivity of early red cell progenitors to iron deprivation, known as the erythroid iron restriction response, serves as a basis for human anemias globally. This response impairs erythropoietin-driven erythropoiesis and underlies erythropoietic repression in iron deficiency anemia. Mechanistically, the erythroid iron restriction response results from inactivation of aconitase enzymes and can be suppressed by providing the aconitase product isocitrate. Recent studies have implicated the erythroid iron restriction response in anemia of chronic disease and inflammation (ACDI), offering new therapeutic avenues for a major clinical problem; however, inflammatory signals may also directly repress erythropoiesis in ACDI. Here, we show that suppression of the erythroid iron restriction response by isocitrate administration corrected anemia and erythropoietic defects in rats with ACDI. In vitro studies demonstrated that erythroid repression by inflammatory signaling is potently modulated by the erythroid iron restriction response in a kinase-dependent pathway involving induction of the erythroid-inhibitory transcription factor PU.1. These results reveal the integration of iron and inflammatory inputs in a therapeutically tractable erythropoietic regulatory circuit.

  4. Blood Flow Restricted Exercise and Vascular Function

    Directory of Open Access Journals (Sweden)

    Masahiro Horiuchi

    2012-01-01

    Full Text Available It is established that regular aerobic training improves vascular function, for example, endothelium-dependent vasodilatation and arterial stiffness or compliance and thereby constitutes a preventative measure against cardiovascular disease. In contrast, high-intensity resistance training impairs vascular function, while the influence of moderate-intensity resistance training on vascular function is still controversial. However, aerobic training is insufficient to inhibit loss in muscular strength with advancing age; thus, resistance training is recommended to prevent sarcopenia. Recently, several lines of study have provided compelling data showing that exercise and training with blood flow restriction (BFR leads to muscle hypertrophy and strength increase. As such, BFR training might be a novel means of overcoming the contradiction between aerobic and high-intensity resistance training. Although it is not enough evidence to obtain consensus about impact of BFR training on vascular function, available evidences suggested that BFR training did not change coagulation factors and arterial compliance though with inconsistence results in endothelial function. This paper is a review of the literature on the impact of BFR exercise and training on vascular function, such as endothelial function, arterial compliance, or other potential factors in comparison with those of aerobic and resistance training.

  5. Measuring Regulatory Restrictions in Logistics Services

    OpenAIRE

    Claire HOLLWEG; Marn-Heong WONG

    2009-01-01

    This study measures the extent of restrictions on trade in logistics services in the ASEAN+6 economies by constructing a logistics regulatory restrictiveness index for each economy that quantifies the extent of government regulations faced by logistics service providers. This is the first study of its kind to construct a regulatory index of the entire logistics sector, which includes the main modes of international transport and customs restrictions. The indices show that large differences ex...

  6. Restrictive Factors for Economic Growth in Developing Countries

    OpenAIRE

    Bucur Ion; Bucur Cristian

    2013-01-01

    Economic growth reflects the ability of an economy to produce more goods, in the structure and quality demanded by consumers. Growth influence decisive the existing living standard in a country. Developing countries are characterized in a greater extent than developed countries by insufficient financial resources designed both to increase the volume of investment resources and their efficient use. Increasing economic resources requires investments and lead to increased production.

  7. The Restriction .on Educational Quality in Rural Schools

    Institute of Scientific and Technical Information of China (English)

    艾丽娜

    2012-01-01

    In order to understand the educational quality in rural schools, I went deep into Huangjia Middle School( situated in Northern China) to make the research. In this article, I focus on the restrictions on educational qualitys, which is one of the main themes about rural education. The factors influencing quality in rural schools are analyzed in this article .It is concluded that educational quality depends on the relationship of teaching and learning and its supporting context.

  8. Restricted Interests and Teacher Presentation of Items

    Science.gov (United States)

    Stocco, Corey S.; Thompson, Rachel H.; Rodriguez, Nicole M.

    2011-01-01

    Restricted and repetitive behavior (RRB) is more pervasive, prevalent, frequent, and severe in individuals with autism spectrum disorders (ASDs) than in their typical peers. One subtype of RRB is restricted interests in items or activities, which is evident in the manner in which individuals engage with items (e.g., repetitious wheel spinning),…

  9. 33 CFR 203.46 - Restrictions.

    Science.gov (United States)

    2010-07-01

    ... Flood Control Works Damaged by Flood or Coastal Storm: The Corps Rehabilitation and Inspection Program § 203.46 Restrictions. (a) Restrictions to flood control works. Flood control works are designed and...) Non-flood related rehabilitation. Rehabilitation of flood control structures damaged by...

  10. 7 CFR 400.407 - Restricted access.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 6 2010-01-01 2010-01-01 false Restricted access. 400.407 Section 400.407 Agriculture... Social Security Account Numbers and Employer Identification Numbers § 400.407 Restricted access. The Manager, other officer, or employee of FCIC or an authorized person may have access to the SSNs and...

  11. 地方本科高校专业课程双语教学的制约因素与模式--以A学院《西方经济学》课程为例%Study on the Restrictive Factors and Methods of Bilingual Teaching in Local University --- A Case Study Based on the Teach of Western Economics in A University

    Institute of Scientific and Technical Information of China (English)

    谢卿

    2014-01-01

    As a typical local University in the western region ,A University has less Research and Practice in bilingual teach-ing .Many restrictive factors such as faculty、the quality of students、course selection ,teaching concept and management mode turn the bilingual teaching into a difficult subject .This paper takes the teaching of Western Economics in A University as an example . It indicates the goals of bilingual education and summarizes the main problems in bilingual teaching .Then it give some suggestion to promote undergraduate bilingual education of specialized courses .%A学院作为一所典型的西部新建地方本科高校,在双语教学的实践和研究方面才刚刚起步,在师资力量、学生素质、教材选用、教学理念、管理机制等方面存在诸多制约因素,需要从实际出发,不断研究和实践,探索出符合自身特点的双语教学模式。

  12. 甘南藏区数学课堂教学中数学交流的制约因素及对策思考%Restricts in the Gannan Tibet Area Mathematics Teaching Mathematics Exchange Factor Brief Analysis and the Strategy Ponder

    Institute of Scientific and Technical Information of China (English)

    王大胄

    2011-01-01

    In the Gannan Tibet Area Middle school mathematics classroom instruction mathematics exchange is short of restricts one of its mathematics education lag factors. The article through analyzes in the Gannan Tibet Area Nationality Middle school mathematics classroom instruction mathematics exchange present situation, the investigation now in the classroom instruction mathematics exchange implementation condition, as well as the Tibetan national minority middle school students to mathematics exchange's understanding, to affect in the Gannan Tibet area mathematics classroom instruction mathematics exchange many factors--Exchange consciousness, the teaching art level, mathematics power of thought that mathematical linguistics ability and so on has carried on the brief analysis, had pointed out in the Gannan race area mathematics classroom instruction mathematics exchange exists the actual problem, and proposed the dealing with strategy.%甘南藏区中学数学课堂教学中数学交流欠缺是制约其数学教育滞后的因素之一.文章通过剖析甘南藏区民族中学数学课堂教学中数学交流的现状,调查当今课堂教学中数学交流实施的状况,以及藏族中学学生对数学交流的认识,对影响甘南藏区数学课堂教学中数学交流的诸多因素一交流意识、教学艺术水平、数学思维能力、数学语言能力等进行了浅析,指出了甘南族区数学课堂教学中数学交流所存在的实际问题,并提出了应对策略.

  13. Distinct patterns of IFITM-mediated restriction of filoviruses, SARS coronavirus, and influenza A virus.

    Directory of Open Access Journals (Sweden)

    I-Chueh Huang

    Full Text Available Interferon-inducible transmembrane proteins 1, 2, and 3 (IFITM1, 2, and 3 are recently identified viral restriction factors that inhibit infection mediated by the influenza A virus (IAV hemagglutinin (HA protein. Here we show that IFITM proteins restricted infection mediated by the entry glycoproteins (GP(1,2 of Marburg and Ebola filoviruses (MARV, EBOV. Consistent with these observations, interferon-β specifically restricted filovirus and IAV entry processes. IFITM proteins also inhibited replication of infectious MARV and EBOV. We observed distinct patterns of IFITM-mediated restriction: compared with IAV, the entry processes of MARV and EBOV were less restricted by IFITM3, but more restricted by IFITM1. Moreover, murine Ifitm5 and 6 did not restrict IAV, but efficiently inhibited filovirus entry. We further demonstrate that replication of infectious SARS coronavirus (SARS-CoV and entry mediated by the SARS-CoV spike (S protein are restricted by IFITM proteins. The profile of IFITM-mediated restriction of SARS-CoV was more similar to that of filoviruses than to IAV. Trypsin treatment of receptor-associated SARS-CoV pseudovirions, which bypasses their dependence on lysosomal cathepsin L, also bypassed IFITM-mediated restriction. However, IFITM proteins did not reduce cellular cathepsin activity or limit access of virions to acidic intracellular compartments. Our data indicate that IFITM-mediated restriction is localized to a late stage in the endocytic pathway. They further show that IFITM proteins differentially restrict the entry of a broad range of enveloped viruses, and modulate cellular tropism independently of viral receptor expression.

  14. Restriction beyond the restriction point: mitogen requirement for G2 passage

    Directory of Open Access Journals (Sweden)

    te Riele Hein

    2006-05-01

    Full Text Available Abstract Cell proliferation is dependent on mitogenic signalling. When absent, normal cells cannot pass the G1 restriction point, resulting in cell cycle arrest. Passage through the G1 restriction point involves inactivation of the retinoblastoma protein family. Consequently, loss of the retinoblastoma protein family leads to loss of the G1 restriction point. Recent work in our lab has revealed that cells possess yet another mechanism that restricts proliferation in the absence of mitogens: arrest in the G2 phase of the cell cycle. Here, we discuss the similarities and differences between these restriction points and the roles of cyclin-dependent kinase inhibitors (CKIs herein.

  15. Analysis of Restrictive Environments in the South-West Oltenia Development Region

    Directory of Open Access Journals (Sweden)

    Radu Matei Cocheci

    2016-12-01

    Full Text Available Restrictive environments can be defined as an area within a territorial system where development is constrained either by natural factors or anthropogenic factors. This paper aims to identify restrictive environments through multi-criteria analysis of Romania’s South West Oltenia development region, known for its issues regarding open-pit mining, desertification or flood risk. In order to achieve this, I proposed a typology of restrictive environments, based on an extensive literature review of natural and anthropogenic factors that can limit development. For each of the ten environmental restrictiveness types identified, several criteria were proposed, which were then weighted as a result of a questionnaire addressed to experts in the field of territorial planning. Based on the questionnaire results, an index of environmental restrictiveness is computed at LAU 2 level for the entire South-West Oltenia development region. The territorialized index highlights the environmental restrictiveness of areas susceptible to flood risk (e.g. along the Jiu valley, but also the problems faced by mining areas (Motru-Rovinari or isolated mountain areas. The computed index represents a first step towards the definition of potential inter-communal cooperation structures, that could become the object of territorial planning instruments aimed at mitigating restrictive environments.

  16. Restriction enzyme mining for SNPs in genomes.

    Science.gov (United States)

    Chuang, Li-Yeh; Yang, Cheng-Hong; Tsui, Ke-Hung; Cheng, Yu-Huei; Chang, Phei-Lang; Wen, Cheng-Hao; Chang, Hsueh-Wei

    2008-01-01

    Many different single nucleotide polymorphisms (SNPs) genotyping methods have been developed recently. However, most of them are expensive. Using restriction enzymes for SNP genotyping is a cost-effective method. However, restriction enzyme mining for SNPs in a genome sequence is still challenging for researchers who do not have a background in genomics and bioinformatics. In this review, the basic bioinformatics tools used for restriction enzyme mining for SNP genotyping are summarized and described. The objectives of this paper include: i) the introduction of SNPs, genotyping and PCR-restriction fragment length polymorphism (RFLP); ii) a review of components for genotyping software, including tools for primer design only or restriction enzyme mining only; iii) a review of software providing the flanking sequence for primer design; iv) recent advances in PCR-RFLP tools and natural and mutagenic PCR-RFLP; v) highlighting the strategy for restriction enzyme mining for SNP genotyping; vi) a discussion of potential problems for multiple PCR-RFLP. The different implications for restriction enzymes on sense and antisense strands are also discussed. Our PCR-RFLP freeware, SNP-RFLPing, is included in this review to illustrate many characteristics of PCR-RFLP software design. Future developments will include further sophistication of PCR-RFLP software in order to provide better visualization and a more interactive environment for SNP genotyping and to integrate the software with other tools used in association studies.

  17. Urban water restrictions: Attitudes and avoidance

    Science.gov (United States)

    Cooper, Bethany; Burton, Michael; Crase, Lin

    2011-12-01

    In most urban cities across Australia, water restrictions remain the dominant policy mechanism to restrict urban water consumption. The extensive adoption of water restrictions as a means to limit demand, over several years, means that Australian urban water prices have consistently not reflected the opportunity cost of water. Given the generally strong political support for water restrictions and the likelihood that they will persist for some time, there is value in understanding households' attitudes in this context. More specifically, identifying the welfare gains associated with avoiding urban water restrictions entirely would be a nontrivial contribution to our knowledge and offer insights into the benefits of alternative policy responses. This paper describes the results from a contingent valuation study that investigates consumers' willingness to pay to avoid urban water restrictions. Importantly, the research also investigates the influence of cognitive and exogenous dimensions on the utility gain associated with avoiding water restrictions. The results provide insights into the impact of the current policy mechanism on economic welfare.

  18. Restrictive extraocular myopathy: A presenting feature of acromegaly

    Directory of Open Access Journals (Sweden)

    Steven Heireman

    2011-01-01

    Full Text Available A 45-year-old man presented with binocular diplopia in primary gaze for 1 year. Orthoptic evaluation showed 10-prism diopter right eye hypotropia and 6-prism diopter right eye esotropia. The elevation and abduction of the right eye were mechanically restricted. This was associated with systemic features suggestive of acromegaly. Magnetic resonance imaging (MRI of the brain demonstrated a pituitary macroadenoma. An elevated serum insulin-like growth factor I level and the failure of growth hormone suppression after an oral glucose load biochemically confirmed the diagnosis of acromegaly. Computed tomography (CT of the orbit demonstrated bilateral symmetrical enlargement of the medial rectus and inferior rectus muscle bellies. All tests regarding Graves-Basedow disease were negative. Although rare, diplopia due to a restrictive extraocular myopathy could be the presenting symptom of acromegaly.

  19. Multiple lysines combined in HIV-1 Vif determines the responsiveness to CBF-β.

    Science.gov (United States)

    Ai, Youwei; Ma, Jianzhang

    2015-02-13

    The Vif (viral infectivity factor) protein of human immunodeficiency virus type-1 (HIV-1) is critical for HIV-1 infectivity. CBF-β is required for HIV-1 Vif function, as it increases the steady-state level of the HIV-1 Vif protein to promote host restriction factor APOBEC3 degradation. However, the precise mechanism by which CBF-β promotes HIV-1 Vif levels remains unclear. In the present study, we provided evidences that CBF-β promoted steady-state levels of HIV-1 Vif by inhibiting the degradation of HIV-1 Vif through the proteasome pathway. Our results reveal a new mechanism by which a cellular protein supports viral infectivity by inhibiting viral protein degradation.

  20. The Frattini Subalgebra of Restricted Lie Superalgebras

    Institute of Scientific and Technical Information of China (English)

    Liang Yun CHEN; Dao Ji MENG; Yong Zheng ZHANG

    2006-01-01

    In the present paper, we study the Frattini subalgebra of a restricted Lie superalgebra (L, [p]). We show first that if L = A1 (⊙) A2 (⊙) … (⊙) An, then φp (L) = φp (A1) + φp (A2) +… +φp (An),where each Ai is a p-ideal of L. We then obtain two results: F(L) = φ(L) = J(L) = L(1) if and only if L is nilpotent; Fp(L) and F(L) are nilpotent ideals of L if L is solvable. In addition, necessary and sufficient conditions are found for φp-free restricted Lie superalgebras. Finally, we discuss the relationships of E-p-restricted Lie superalgebras and E-restricted Lie superalgebras.

  1. Restriction/modification polypeptides, polynucleotides, and methods

    Energy Technology Data Exchange (ETDEWEB)

    Westpheling, Janet; Chung, DaeHwan; Huddleston, Jennifer; Farkas, Joel A

    2015-02-24

    The present invention relates to the discovery of a novel restriction/modification system in Caldicellulosiruptor bescii. The discovered restriction enzyme is a HaeIII-like restriction enzyme that possesses a thermophilic activity profile. The restriction/modification system also includes a methyltransferase, M.CbeI, that methylates at least one cytosine residue in the CbeI recognition sequence to m.sup.4C. Thus, the invention provides, in various aspects, isolated CbeI or M.CbeI polypeptides, or biologically active fragments thereof; isolated polynucleotides that encode the CbeI or M.CbeI polypeptides or biologically active fragments thereof, including expression vectors that include such polynucleotide sequences; methods of digesting DNA using a CbeI polypeptide; methods of treating a DNA molecule using a M.CbeI polypeptide; and methods of transforming a Caldicellulosiruptor cell.

  2. Restricted Coherent Risk Measures and Actuarial Solvency

    Directory of Open Access Journals (Sweden)

    Christos E. Kountzakis

    2012-01-01

    Full Text Available We prove a general dual representation form for restricted coherent risk measures, and we apply it to a minimization problem of the required solvency capital for an insurance company.

  3. 7 CFR 982.50 - Restricted obligation.

    Science.gov (United States)

    2010-01-01

    ... WASHINGTON Order Regulating Handling Control of Distribution § 982.50 Restricted obligation. (a) No handler... procedures as are necessary to facilitate the administration of this option among handlers. (d) Whenever...

  4. Crowding during restricted and free viewing.

    Science.gov (United States)

    Wallace, Julian M; Chiu, Michael K; Nandy, Anirvan S; Tjan, Bosco S

    2013-05-24

    Crowding impairs the perception of form in peripheral vision. It is likely to be a key limiting factor of form vision in patients without central vision. Crowding has been extensively studied in normally sighted individuals, typically with a stimulus duration of a few hundred milliseconds to avoid eye movements. These restricted testing conditions do not reflect the natural behavior of a patient with central field loss. Could unlimited stimulus duration and unrestricted eye movements change the properties of crowding in any fundamental way? We studied letter identification in the peripheral vision of normally sighted observers in three conditions: (i) a fixation condition with a brief stimulus presentation of 250 ms, (ii) another fixation condition but with an unlimited viewing time, and (iii) an unrestricted eye movement condition with an artificial central scotoma and an unlimited viewing time. In all conditions, contrast thresholds were measured as a function of target-to-flanker spacing, from which we estimated the spatial extent of crowding in terms of critical spacing. We found that presentation duration beyond 250 ms had little effect on critical spacing with stable gaze. With unrestricted eye movements and a simulated central scotoma, we found a large variability in critical spacing across observers, but more importantly, the variability in critical spacing was well correlated with the variability in target eccentricity. Our results assure that the large body of findings on crowding made with briefly presented stimuli remains relevant to conditions where viewing time is unconstrained. Our results further suggest that impaired oculomotor control associated with central vision loss can confound peripheral form vision beyond the limits imposed by crowding.

  5. Feed restriction enhances the depressive effects of erythromycin on equine hindgut microbial metabolism in vitro.

    Science.gov (United States)

    Kuhn, Manuela; Guschlbauer, Maria; Feige, Karsten; Schluesener, Michael; Bester, Kai; Beyerbach, Martin; Breves, Gerhard

    2012-01-01

    Equine typholocolitis is a sporadic diarrheal disease causing high mortality rates. One of the risk factors responsible for this is the oral application of the macrolide antibiotic erythromycin. The aim of the present in vitro study was to investigate whether erythromycin in combination with feed restriction provokes changes in microbial hindgut metabolism and could therefore be involved in the pathogenesis of equine typhlocolitis. As application of erythromycin and feed restriction are risk factors for equine typhlocolitis, both factors were chosen to investigate their individual and combined effects on hindgut microbial metabolism. The colon simulation technique (Cositec) was used to evaluate biochemical parameters of microbial metabolism. Production rates of the acetate, proprionate and butyrate were measured as quantitative parameters of microbial fermentation. Application of erythromycin (10 mg/d) predominantly decreased the production rates of propionate. Reducing the fermentable substrate to 30% induced an even more pronounced impairment. The detrimental effects of feed restriction on the production rates of short-chain fatty acids (SCFA) were enhanced when feed restriction was combined with the application of erythromycin. Irrespective of erytrhomycin, the butyrate fermentation rate was completely inhibited by feed restriction within two days after start of restriction. The reduction in butyrate fermentation rate has to be discussed as a pathophysiological factor for the onset of acute typhlocolitis.

  6. Date restricted queries in web search engines

    OpenAIRE

    Lewandowski, Dirk

    2004-01-01

    Search engines usually offer a date restricted search on their advanced search pages. But determining the actual update of a web page is not without problems. We conduct a study testing date restricted queries on the search engines Google, Teoma and Yahoo!. We find that these searches fail to work properly in the examined engines. We discuss implications of this for further research and search engine development.

  7. Dietary restriction causing iodine-deficient goitre.

    Science.gov (United States)

    Cheetham, Tim; Plumb, Emma; Callaghan, James; Jackson, Michael; Michaelis, Louise

    2015-08-01

    Iodine-deficient goitre was common in some parts of the UK prior to the introduction of salt iodisation. Many contemporary salt preparations do not contain much iodine, and there are renewed concerns about the iodine status of the population. We present a boy with severe allergy who developed goitre and significant thyroid dysfunction in association with an iodine-deficient 'food-restricted' diet. The case highlights the importance of a comprehensive nutritional assessment in all children on multiple food restrictions.

  8. Policy restrictions, democratic deficit and redistribution

    OpenAIRE

    2008-01-01

    Restrictions to the range of policies available to governments are often recommended as a solution to coordination failures or time inconsistency problems. However, policy restrictions can have important drawbacks that have been generally ignored so far. When the hands of governments are tied, citizens have lower incentives to be informed on political matters and to participate in collective decision-making processes, since private returns from political information are lower. This mechanism ...

  9. Considerations on Restricting Factors of Implementing Sunlight Sports among Disabled Students in University%高校残障学生实施“阳光体育运动”的障碍因素分析及对策研究

    Institute of Scientific and Technical Information of China (English)

    陶权; 王道君

    2012-01-01

    Under the background of sunlight sports, using the method of literature review, questlonnmre and mathematical statistics, this paper makes analysis on influence factors of implementing sunlight sports among disa- bled students in university. The result shows that sunlight sports implementation of disabled students face the sys- tem loss, imperfect management system, physical education lag, unfulfilled 1 extracurricular sports activities and idea restriction. Based on existing problems, some references for implementing sunlight sports of college disabled students are provided.%以“阳光体育运动”为背景,运用问卷调查法、文献资料法、数理统计等方法,对高校残障学生开展“阳光体育运动”的影响因素进行调查分析。认为:残障学生实施“阳光体育运动”制度保障体系缺失、管理体制不健全、体育教育滞后、课外体育活动得不到良好的落实、观念制约等是影响高校残障学生“阳光体育运动”实施的主要因素。针对存在的问题提出解决对策,为“阳光体育运动”在高校残障学生中有效的实施提供参考。

  10. Reality Factors of Restricting Employment of Tibetan and the Legal Response---A case study of the Tibetans in Lanzhou%制约城市藏族就业的现实因素与法律回应--以兰州为例

    Institute of Scientific and Technical Information of China (English)

    吴宇; 罗维鹏

    2014-01-01

    The main factors restricting the employment of minorities are degree of sinicization,educational back-ground,stereotypes,gender differences and work experience.Our Constitution,the law and the law of the follow-ing normative legal documents respond to this,but the results are not satisfactory.The reason lies in the irrational structure of the relevant legal norms system,lack of systematicness and independence,deviations of legal areas of concern as well as public awareness of the law.We should take some measures to adjust the structure,chang the legislative areas of concern,and develop constitutional culture.and make more effective legal response to this.%现实中制约少数民族就业的因素主要有汉化程度、受教育程度、刻板印象、性别差异、工作经验等,我国宪法、法律和法律以下的规范性法律文件都对此有所回应,但效果却不明显,其原因在于相关法律规范体系的结构不合理、内容缺乏系统性和独立性、法律关注领域存在偏差以及公众法律意识淡薄等。应从调整立法结构、转变立法关注领域、培养宪法文化三方面入手,对此作出更加有效的法律应对。

  11. Restrict Gymnastics General to Build Lesson Teaching Factors on the Quality of the Survey ——in Nanjing Sports Institute as an Example%制约体操普修课教学质量的因素调查——以南京体育学院为例

    Institute of Scientific and Technical Information of China (English)

    杜家俊

    2012-01-01

    通过文献资料法、问卷调查法、专家访谈法和数理统计法对制约南京体院体操普修课教学质量的因素进行了调查,发现轻器械体操的数量和质量不能满足体操教学的需要;体操教师以中青年教师为主,目前还没有教授,没有博士,只有4名硕士,职称层次和学历层次还不够高;体操课内容多,动作难度大,目前学时略显不足;缺少培养学生体操教学能力的重要手段,学生的体操教学能力一般。%Through the literature material law,the questionnaire survey procedure,the expert interview law and the mathematical statistics to restrict nanjing skill-studying gymnastics general to build lesson teaching quality factor to carry on the investigation,found that light instrument gymnastics quantity and quality can not meet the needs of the gymnastics teaching;The gym teacher to young and middle-aged teachers give priority to,there is no professor,no doctor,only four master degree,the title level and education background is not enough high;Gymnastics class content,difficulty of movement big,the school insufficient;The lack of cultivating students' ability to gymnastics teaching an important means,students' gymnastics teaching ability general.

  12. Antenatal taurine reduces cerebral cell apoptosis in fetal rats with intrauterine growth restriction*

    Institute of Scientific and Technical Information of China (English)

    Jing Liu; Xiaofeng Wang; Ying Liu; Na Yang; Jing Xu; Xiaotun Ren

    2013-01-01

    From pregnancy to parturition, Sprague-Dawley rats were daily administered a low protein diet to establish a model of intrauterine growth restriction. From the 12th day of pregnancy, 300 mg/kg rine was daily added to food until spontaneous delivery occurred. Brain tissues from normal neo-natal rats at 6 hours after delivery, neonatal rats with intrauterine growth restriction, and neonatal rats with intrauterine growth restriction undergoing taurine supplement were obtained for further experiments. The terminal deoxyribonucleotidyl transferase (TdT)-mediated biotin-16-dUTP nick-end labeling assay revealed that the number of apoptotic cel s in the brain tissue of neonatal rats with intrauterine growth restriction significantly increased. Taurine supplement in pregnant rats reduced cel apoptosis in brain tissue from neonatal rats with intrauterine growth restriction. nohistochemical staining revealed that taurine supplement increased glial cel line-derived neuro-trophic factor expression and decreased caspase-3 expression in the cerebral cortex of intrauterine growth-restricted fetal rats. These results indicate that taurine supplement reduces cel apoptosis through the glial cel line-derived neurotrophic factor-caspase-3 signaling pathway, resulting in a protective effect on the intrauterine growth-restricted fetal rat brain.

  13. Cellular restriction of retrovirus particle-mediated mRNA transfer.

    Science.gov (United States)

    Galla, Melanie; Schambach, Axel; Towers, Greg J; Baum, Christopher

    2008-03-01

    Analyzing cellular restriction mechanisms provides insight into viral replication strategies, identifies targets for antiviral drug design, and is crucial for the development of novel tools for experimental or therapeutic delivery of genetic information. We have previously shown that retroviral vector mutants that are unable to initiate reverse transcription mediate a transient expression of any sequence which replaces the gag-pol transcription unit, a process we call retrovirus particle-mediated mRNA transfer (RMT). Here, we further examined the mechanism of RMT by testing its sensitivity to cellular restriction factors and short hairpin RNAs (shRNAs). We found that both human TRIM5alpha and, to a lesser extent, Fv1 effectively restrict RMT if the RNA is delivered by a restriction-sensitive capsid. While TRIM5alpha restriction of RMT led to reduced levels of retroviral mRNA in target cells, restriction by Fv1 did not. Treatment with the proteasome inhibitor MG132 partially relieved TRIM5alpha-mediated restriction of RMT. Finally, cells expressing shRNAs specifically targeting the retroviral mRNA inhibited RMT particles, but not reverse-transcribing particles. Retroviral mRNA may thus serve as a translation template if not used as a template for reverse transcription. Our data imply that retroviral nucleic acids become accessible to host factors, including ribosomes, as a result of particle remodeling during cytoplasmic trafficking.

  14. Dietary restriction with and without caloric restriction for healthy aging [version 1; referees: 3 approved

    Directory of Open Access Journals (Sweden)

    Changhan Lee

    2016-01-01

    Full Text Available Caloric restriction is the most effective and reproducible dietary intervention known to regulate aging and increase the healthy lifespan in various model organisms, ranging from the unicellular yeast to worms, flies, rodents, and primates. However, caloric restriction, which in most cases entails a 20–40% reduction of food consumption relative to normal intake, is a severe intervention that results in both beneficial and detrimental effects. Specific types of chronic, intermittent, or periodic dietary restrictions without chronic caloric restriction have instead the potential to provide a significant healthspan increase while minimizing adverse effects. Improved periodic or targeted dietary restriction regimens that uncouple the challenge of food deprivation from the beneficial effects will allow a safe intervention feasible for a major portion of the population. Here we focus on healthspan interventions that are not chronic or do not require calorie restriction.

  15. Variants of early-onset restrictive eating disturbances in middle childhood

    OpenAIRE

    Kurz, Susanne; van Dyck, Zoé; Dremmel, Daniela; Munsch, Simone; Hilbert, Anja

    2016-01-01

    Objective: This study sought to determine the factor structure of the newly developed self-report screening questionnaire Eating Disturbances in Youth-Questionnaire (EDY-Q) as well as to report the distribution of variants of early-onset restrictive eating disturbances characteristic of avoidant/restrictive food intake disorder (ARFID) in a middle childhood population sample. Method: Using the EDY-Q, a total of 1444 children aged 8-13 years were screened in elementary schools in Switzerland v...

  16. Cytosine methylation dysregulation in neonates following intrauterine growth restriction.

    Directory of Open Access Journals (Sweden)

    Francine Einstein

    Full Text Available BACKGROUND: Perturbations of the intrauterine environment can affect fetal development during critical periods of plasticity, and can increase susceptibility to a number of age-related diseases (e.g., type 2 diabetes mellitus; T2DM, manifesting as late as decades later. We hypothesized that this biological memory is mediated by permanent alterations of the epigenome in stem cell populations, and focused our studies specifically on DNA methylation in CD34+ hematopoietic stem and progenitor cells from cord blood from neonates with intrauterine growth restriction (IUGR and control subjects. METHODS AND FINDINGS: Our epigenomic assays utilized a two-stage design involving genome-wide discovery followed by quantitative, single-locus validation. We found that changes in cytosine methylation occur in response to IUGR of moderate degree and involving a restricted number of loci. We also identify specific loci that are targeted for dysregulation of DNA methylation, in particular the hepatocyte nuclear factor 4alpha (HNF4A gene, a well-known diabetes candidate gene not previously associated with growth restriction in utero, and other loci encoding HNF4A-interacting proteins. CONCLUSIONS: Our results give insights into the potential contribution of epigenomic dysregulation in mediating the long-term consequences of IUGR, and demonstrate the value of this approach to studies of the fetal origin of adult disease.

  17. A randomized trial of dietary sodium restriction in CKD.

    Science.gov (United States)

    McMahon, Emma J; Bauer, Judith D; Hawley, Carmel M; Isbel, Nicole M; Stowasser, Michael; Johnson, David W; Campbell, Katrina L

    2013-12-01

    There is a paucity of quality evidence regarding the effects of sodium restriction in patients with CKD, particularly in patients with pre-end stage CKD, where controlling modifiable risk factors may be especially important for delaying CKD progression and cardiovascular events. We conducted a double-blind placebo-controlled randomized crossover trial assessing the effects of high versus low sodium intake on ambulatory BP, 24-hour protein and albumin excretion, fluid status (body composition monitor), renin and aldosterone levels, and arterial stiffness (pulse wave velocity and augmentation index) in 20 adult patients with hypertensive stage 3-4 CKD as phase 1 of the LowSALT CKD study. Overall, salt restriction resulted in statistically significant and clinically important reductions in BP (mean reduction of systolic/diastolic BP, 10/4 mm Hg; 95% confidence interval, 5 to 15 /1 to 6 mm Hg), extracellular fluid volume, albuminuria, and proteinuria in patients with moderate-to-severe CKD. The magnitude of change was more pronounced than the magnitude reported in patients without CKD, suggesting that patients with CKD are particularly salt sensitive. Although studies with longer intervention times and larger sample sizes are needed to confirm these benefits, this study indicates that sodium restriction should be emphasized in the management of patients with CKD as a means to reduce cardiovascular risk and risk for CKD progression.

  18. Fasting and Caloric Restriction in Cancer Prevention and Treatment.

    Science.gov (United States)

    Brandhorst, Sebastian; Longo, Valter D

    Cancer is the second leading cause of death in the USA and among the leading major diseases in the world. It is anticipated to continue to increase because of the growth of the aging population and prevalence of risk factors such as obesity, smoking, and/or poor dietary habits. Cancer treatment has remained relatively similar during the past 30 years with chemotherapy and/or radiotherapy in combination with surgery remaining the standard therapies although novel therapies are slowly replacing or complementing the standard ones. According to the American Cancer Society, the dietary recommendation for cancer patients receiving chemotherapy is to increase calorie and protein intake. In addition, there are no clear guidelines on the type of nutrition that could have a major impact on cancer incidence. Yet, various forms of reduced caloric intake such as calorie restriction (CR) or fasting demonstrate a wide range of beneficial effects able to help prevent malignancies and increase the efficacy of cancer therapies. Whereas chronic CR provides both beneficial and detrimental effects as well as major compliance challenges, periodic fasting (PF), fasting-mimicking diets (FMDs), and dietary restriction (DR) without a reduction in calories are emerging as interventions with the potential to be widely used to prevent and treat cancer. Here, we review preclinical and preliminary clinical studies on dietary restriction and fasting and their role in inducing cellular protection and chemotherapy resistance.

  19. RESTRICTIONS BY THE USE OF WEAPONS OF RUSSIAN CITIZENS

    Directory of Open Access Journals (Sweden)

    Lyatsa A. Kodzokova

    2016-01-01

    Full Text Available Abstract: The article considers the restrictions imposed on the circulation of civilian and service weapons. The author analyzes the restrictions on the circulation of weapons, the procedure for their implementation in practice. Federal Law "On weapons" only in paragraph 6 p. 1, art. 6 "Restrictions imposed on the circulation of civilian and service weapons" refers to the prohibition of 'turnover as a civilian and service weapons and other items affecting the action is based on the use of radiation and biological factors; weapons and other items affecting the action is based on the use of electromagnetic, light, thermal, subsonic or ultrasonic radiation and which have output parameters that exceed the value set by state standards of the Russian Federation and the relevant regulations of the federal executive authority in the field of public health, as well as these weapons and items produced outside the Russian territory " How to regard this provision of the law? As the transfer of new weapons, not specific item. 25 of the Federal Law "On weapons", or items prohibited for circulation in the territory of our state? This inconsistency decreases the effectiveness of the legal regulation of arms trafficking. Unification of definitions in this area will allow applying the law correctly and reasonably, including criminal. But for this it is necessary taking into account the experience and the modern needs of the various branches of law provide a clearer definition of "weapon" and its species. The author's conclusions may be used in law enforcement. 

  20. Heart Morphometry in Rats with Intrauterine Growth Restriction

    Directory of Open Access Journals (Sweden)

    Claudia Joffre Fríaz

    2015-12-01

    Full Text Available Background: epidemiological and experimental studies suggest that cardiovascular disease in adulthood is influenced by prenatal or early postnatal events, regardless of lifestyle-related risk factors. Objective: to characterize the heart morphometry in Wistar rats with intrauterine growth restriction and to determine the differences between adolescents and adults of both sexes as well as the association with some morphometric variables at birth. Methods: a total of 80 rats in the control group and 80 in the experimental group were studied. The following morphometric variables were analyzed in the newborns: weight, height in addition to size, weight and volume of the heart, all in millimeters. Results: low birth weight resulting from intrauterine growth restriction caused changes in heart morphometry, especially in heart weight and thickness of the left ventricle. These changes were observed in both sexes during adolescence and showed a slight predominance in adult males. Conclusions: these results led to an increased knowledge of the events involved in heart development in response to nutrient restriction in utero, which could contribute to the design of health strategies to reduce morbidity and perinatal mortality from heart diseases.

  1. Miles In Trail (MIT) Restrictions: A Perspective

    Science.gov (United States)

    Kopardekar, Parimal; Green, Steven; Roherty, Tom; Aston, John

    2003-01-01

    Miles-in-trail restrictions are issued to meet the airport and/or airspace capacity. The purpose of this paper is to review the currently practiced miles-in-trail operations for traffic flow management at a typical en route Air Traffic Control Center. The paper describes roles and considerations of both traffic management coordinators and the controllers in planning, coordination, execution, and monitoring of miles-in-trail restrictions. The paper addresses the type of decisions that traffic management coordinators must make and the different information required to plan and monitor miles-in-trail restrictions. The implications of miles-in-trail restrictions on controller workload are also addressed. Using the Cleveland center as an example, the paper also identified some challenging traffic situations that required miles-in-trail restrictions on a regular basis. The paper is expected to benefit the research and development community as it provides the current challenges in traffic flow management and strengths and weakness of miles-in-trail operations.

  2. Newer antidiabetic drugs and calorie restriction mimicry

    Directory of Open Access Journals (Sweden)

    Sanjay Kalra

    2016-01-01

    Full Text Available De-acceleration of aging and delayed development of age-related morbidity accompanies the restriction of calories (without malnutrition in laboratory mice, nematodes, yeast, fish, and dogs. Recent results from long-term longitudinal studies conducted on primates have suggested longevity benefits of a 30% restriction of calories in rhesus monkeys as well. Among calorie restricted rhesus monkeys one of the mechanisms for the improvement in lifespan was the reduction in the development of glucose intolerance and cardiovascular disease. Although there are no comparable human studies, it is likely that metabolic and longevity benefits will accompany a reduction in calories in humans as well. However, considering the difficulties in getting healthy adults to limit food intake science has focused on understanding the biochemical processes that accompany calorie restriction (CR to formulate drugs that would mimic the effects of CR without the need to actually restrict calories. Drugs in this emerging therapeutic field are called CR mimetics. Some of the currently used anti-diabetic agents may have some CR mimetic like effects. This review focuses on the CR mimetic properties of the currently available anti-diabetic agents.

  3. Ruminant models of prenatal growth restriction.

    Science.gov (United States)

    Anthony, R V; Scheaffer, A N; Wright, C D; Regnault, T R H

    2003-01-01

    Intrauterine growth restriction (IUGR) is a significant health issue that not only affects infant mortality and morbidity, but may also predispose individuals to coronary heart disease, diabetes, hypertension and stroke as adults. The majority of IUGR pregnancies in humans are characterized by asymmetric fetal growth, resulting from inadequate nutrient transfer to the fetus. Furthermore, most of these pregnancies involve functional placental insufficiency, and may also show altered umbilical velocimetry. As the severity of IUGR increases, the fetus becomes increasingly hypoxic, hypoglycaemic and acidotic. In addition, placental transfer or utilization of some amino acids is known to be altered in IUGR pregnancies. Although a great deal has been learned from clinical studies of human IUGR, appropriate animal models are required to define completely the mechanisms involved in the development of IUGR. The pregnant sheep is a long-standing model for placental-fetal interactions, and fetal growth restriction can be induced in pregnant sheep by maternal nutrient restriction, maternal nutrient excess, administration of glucocorticoid, utero-placental embolization, carunclectomy and maternal hyperthermia. Although all of these sheep models are capable of inducing fetal growth restriction, the degree of restriction is variable. This review compares these sheep models of IUGR with the characteristics of human IUGR.

  4. Semantic congruence reverses effects of sleep restriction on associative encoding.

    Science.gov (United States)

    Alberca-Reina, Esther; Cantero, Jose L; Atienza, Mercedes

    2014-04-01

    Encoding and memory consolidation are influenced by factors such as sleep and congruency of newly learned information with prior knowledge (i.e., schema). However, only a few studies have examined the contribution of sleep to enhancement of schema-dependent memory. Based on previous studies showing that total sleep deprivation specifically impairs hippocampal encoding, and that coherent schemas reduce the hippocampal consolidation period after learning, we predict that sleep loss in the pre-training night will mainly affect schema-unrelated information whereas sleep restriction in the post-training night will have similar effects on schema-related and unrelated information. Here, we tested this hypothesis by presenting participants with face-face associations that could be semantically related or unrelated under different sleep conditions: normal sleep before and after training, and acute sleep restriction either before or after training. Memory was tested one day after training, just after introducing an interference task, and two days later, without any interference. Significant results were evident on the second retesting session. In particular, sleep restriction before training enhanced memory for semantically congruent events in detriment of memory for unrelated events, supporting the specific role of sleep in hippocampal memory encoding. Unexpectedly, sleep restriction after training enhanced memory for both related and unrelated events. Although this finding may suggest a poorer encoding during the interference task, this hypothesis should be specifically tested in future experiments. All together, the present results support a framework in which encoding processes seem to be more vulnerable to sleep loss than consolidation processes.

  5. Potentializing and restrictive factors in the implementation of the balanced scorecard: a study in a contruction firm in the state of Ceará Fatores potencializadores e restritivos à implantação do Balanced Scorecard:um estudo em uma empresa de construção civil do Ceará

    Directory of Open Access Journals (Sweden)

    Roberta Catrib de Azevedo Lemos

    2011-12-01

    Full Text Available Normal 0 21 false false false PT-BR X-NONE X-NONE MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Tabela normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} The Balanced Scorecard (BSC, better known as a method to translate a firm’s mission and strategy into a broad set of performance measurements, has been used for the strategic management of organizations, serving as a measurement system  that, besides the financial goals, includes performance characteristics. This research, which was carried out through a case study, aims at identifying the main potentializing and restrictive factors in the implementation of the BSC in a civil construction firm in the state of Ceará, the Porto Freire Engineering. The bibliographical research, which was based on the managerial reports of the 2003 to 2009 period, showed that the firm conducted the process necessary to the implementation of the BSC for the management of its strategy. The field data were collected through questionnaires and interviews applied, respectively, to the employees and managers who already were in the firm when the BSC was implemented. The questionnaire data show that, among the set of twenty factors considered in the research, only three were deemed potentializing in the implementation of the BSC: technical support, balancing of the four perspectives and preservation of

  6. Sight Restrictions in Maghrib Muslim Architecture

    Directory of Open Access Journals (Sweden)

    Mustapha Ben Hamouche

    1999-12-01

    Full Text Available Sight in Islamic culture is subject to legal restrictions that aim at preserving moral consciousness in Muslim societies. These restrictions have a direct impact on architecture in traditional Muslim cities. Details such as placement of doors and windows, the use of balconies and rooftops, and building heights were shaped by legal reasoning based on sight restrictions. The present study aims at highlighting this legal reasoning system by analyzing legal opinions that were continuously advocated by jurists in response to daily practices, and the legal principles on which these opinions were based. This is expected to contribute in developing a new intellectual discourse on Muslim architecture that could go beyond the present design theories.

  7. 'Liberal' vs. 'restrictive' perioperative fluid therapy

    DEFF Research Database (Denmark)

    Bundgaard-Nielsen, M; Secher, N H; Kehlet, H

    2009-01-01

    found differences in the selected outcome parameters. CONCLUSION: Liberal vs. restrictive fixed-volume regimens are not well defined in the literature regarding the definition, methodology and results, and lack the use of or information on evidence-based standardized perioperative care-principles (fast......BACKGROUND: Several studies have assessed the effect of a 'liberal' vs. a 'restrictive' perioperative fluid regimen on post-operative outcome. The literature was reviewed in order to provide recommendations regarding perioperative fluid regimens. METHODS: A PubMed search identified randomized...... period. Also, information regarding perioperative care and type of anaesthesia was assessed. RESULTS: In the seven randomized studies identified, the range of the liberal intraoperative fluid regimen was from 2750 to 5388 ml compared with 998 to 2740 ml for the restrictive fluid regimen. The period...

  8. Methylation of insulin-like growth factor binding protein 3 gene in neonates with intrauterine growth restriction%胰岛素样生长因子结合蛋白3在宫内生长受限儿中的甲基化研究

    Institute of Scientific and Technical Information of China (English)

    苏爱玲; 蒋犁; 葛芹玉

    2011-01-01

    Objective To study the role of promoter methylation of insulin-like growth factor binding protein 3 (ICFBP3) in intrauterine growth restriction (IUGR). Methods Fifty neonates with IUCR and 30 healthy neonates were enrolled. The promoter methylation status of 1GFBP3 in peripheral blood was evaluated by methylation-specific PCR (MSP) and high resolution melting (HRM) techniques. Results The complete methylation rate, partial methylation rate and non-methylation rate of IGFBP3 promoter in the IUGR group was 4% (2/50) , 40% (20/50) and 56% (28/50) , respectively. The partial methylation rate and non-methylation rate of IGFBP3 promoter in the control group were 13% (4/30) and 87% (26/30) , respectively. There were significant differences in the promoter methylation rate of IGFBP3 between the two groups ( P < 0. 01 ). Conclusions The promoter methylation of IGFBP3 gene is associated with the pathogenesis of IUGR.%目的 探讨胰岛素样生长因子结合蛋白3(IGFBP3)启动子区甲基化状态在胎儿宫内生长受限(IUGR)中的作用.方法 选取IUGR新生儿50例及正常新生儿30例,应用甲基化特异性PCR(MSP)及高分辨率溶解(HRM)技术检测外周血中IGFBP3基因的甲基化状态.结果 IUGR组中IGFBP3启动子区完全甲基化比例为4%(2/50),部分甲基化比例为40%(20/50),未甲基化比例为56%(28/50);对照组中部分甲基化比例为13%(4/30),未甲基化比例为87%(26/30),两组甲基化率差异有统计学意义(P<0.01).结论 IGFBP3基因启动子区的甲基化程度与IUGR的发生有关.

  9. 早产儿发生呼吸窘迫综合征及患儿宫外发育迟缓的相关因素分析%Analysis on the relevant factors of respiratory distress syndrome and ex-trauterine growth restriction for premature infants

    Institute of Scientific and Technical Information of China (English)

    项俊华; 夏红卫

    2015-01-01

    Objective To analyze the relevant factors of respiratory distress syndrome for premature infants and the risk factors of extrauterine growth restriction(EUGR)for the premature infants with respiratory distress syndrome. Methods All 153 premature infants with respiratory distress syndrome were selected as case group, and they were assigned to EUGR group and non-EUGR group on the basis of whether they had EUGR. 200 premature infants without respiratory distress syndrome were selected as control group during the same period. Clinical data of each group were observed and relevant factors were analyzed. Results Differences of incidence rates of EUGR and severe EUGR between the pre-mature infants with respiratory distress syndrome and those without respiratory distress syndrome were statistically sig-nificant (P<0.05). Incidence rates of gestational age, birth weight, multiple pregnancy rate, preventive application rate of PS,antenatal application rate of hormone,fetal distress or asphyxia,amniotic fluid aspiration,intrauterine in-fection, placenta previa/placental abruption, cesarean section, pregnancy-induced hypertension and ges tational dia-betes mellitus were relevant factors of respiratory distress syndrome for premature infants (P<0.05). Gestational age of less than 31 weeks, multiple pregnancy, time reaching total enteral nutrition, feeding intolerance, and time resuming birth weight were independent risk factors of EUGR for premature patients with respiratory distress syndrome (P<0.05). Antenatal application of hormone was the protective factor of EUGR for premature infants with respiratory dis-tress syndrome (P<0.05). Conclusion Young gestational age and multiple pregnancy are common risk factors of respi-ratory distress syndrome and EUGR for premature infants, and antenatal application of hormone has protective effect on the two diseases. Respiratory distress syndrome has obvious adverse effect on infants' extrauterine growth, and EU-GR for premature infants

  10. 12 CFR 575.11 - Operating restrictions.

    Science.gov (United States)

    2010-01-01

    ..., the reference in § 563b.510 of this chapter to five percent refers to minority shareholders. (d) Restrictions on waiver of dividends. No mutual holding company may waive its right to receive any dividend... holding company provides the OTS with written notice of its intent to waive its right to receive...

  11. 48 CFR 225.7007-1 - Restrictions.

    Science.gov (United States)

    2010-10-01

    ... 48 Federal Acquisition Regulations System 3 2010-10-01 2010-10-01 false Restrictions. 225.7007-1 Section 225.7007-1 Federal Acquisition Regulations System DEFENSE ACQUISITION REGULATIONS SYSTEM... subsequent DoD appropriations acts, do not acquire welded shipboard anchor and mooring chain, four inches...

  12. 45 CFR 9.5 - Restrictions.

    Science.gov (United States)

    2010-10-01

    ... DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL ADMINISTRATION USE OF HHS RESEARCH FACILITIES BY ACADEMIC SCIENTISTS, ENGINEERS, AND STUDENTS § 9.5 Restrictions. (a) Each individual authorized to use Department... that the non-Government user will comply with all safety regulations and procedures while using...

  13. 36 CFR 331.18 - Restrictions.

    Science.gov (United States)

    2010-07-01

    ... public health, public safety, security, maintenance, or other reasons in the public interest. Entering or... 331.18 Parks, Forests, and Public Property CORPS OF ENGINEERS, DEPARTMENT OF THE ARMY REGULATIONS..., KENTUCKY AND INDIANA § 331.18 Restrictions. The District Engineer may establish and post a schedule...

  14. Restricted Liberty, Parental Choice and Homeschooling

    Science.gov (United States)

    Merry, Michael S.; Karsten, Sjoerd

    2010-01-01

    In this paper the authors carefully study the problem of liberty as it applies to school choice, and whether there ought to be restricted liberty in the case of homeschooling. They examine three prominent concerns that might be brought against homeschooling, viz., that it aggravates social inequality, worsens societal conflict and works against…

  15. Restricted liberty, parental choice and homeschooling

    NARCIS (Netherlands)

    Merry, M.S.; Karsten, S.

    2010-01-01

    In this paper the authors carefully study the problem of liberty as it applies to school choice, and whether there ought to be restricted liberty in the case of homeschooling. They examine three prominent concerns that might be brought against homeschooling, viz., that it aggravates social inequalit

  16. 12 CFR 1805.808 - Lobbying restrictions.

    Science.gov (United States)

    2010-01-01

    ... 12 Banks and Banking 7 2010-01-01 2010-01-01 false Lobbying restrictions. 1805.808 Section 1805.808 Banks and Banking COMMUNITY DEVELOPMENT FINANCIAL INSTITUTIONS FUND, DEPARTMENT OF THE TREASURY COMMUNITY DEVELOPMENT FINANCIAL INSTITUTIONS PROGRAM Terms and Conditions of Assistance § 1805.808...

  17. Induced Modules of Restricted Lie Superalgebras

    Institute of Scientific and Technical Information of China (English)

    刘文德

    2005-01-01

    In this paper we first prove the PBW theorem for reduced universal enveloping algebras of restricted Lie superalgebras. Then the notion of an induced module is introduced and the dimension formula of induced modules is established.Finally, using the results above, we obtain a property of induced modules pertaining to automorphisms of Lie superalgebras and isomorphisms of modules.

  18. Preventive maintenance at opportunities of restricted duration

    NARCIS (Netherlands)

    R. Dekker (Rommert); E. Smeitink

    1994-01-01

    textabstractThis article deals with the problem of setting priorities for the execution of maintenance packages at randomly occurring opportunities. These opportunities are of restricted duration, implying that only a limited number of packages can be executed. The main idea proposed is to set up a

  19. Restrictive cardiomyopathy. Report of seven cases

    Directory of Open Access Journals (Sweden)

    Fonseca Sánchez Luis Alfonso

    2014-07-01

    Full Text Available Restrictive cardiomyopathy is a disease characterized by ventricular diastolic failure with elevation of end-dyastolic pressure and preserved systolic function. Materials and methods: retrospective study of patients with a diagnosis of restrictive cardiomyopathy. We carry out an analysis of demographic data, clinical presentation, and studies of patients diagnosed in the last 15 years at Instituto Nacional de Pediatría. Results: all included patients had clinical data of heart failure manifested mainly by medium-sized efforts dyspnea on schoolchildren and dyspnea by feeding in infants, as well as polypnea and diaphoresis. The most important signs were hepatomegaly, ascites, and gallop rhythm. Cardiomegaly by right atrial dilatation was the most frequent radiological data. The most frequent electrocardiographic data were dilatation of both atria, ST-segment depression and negative T waves. Echocardiogram showed in all cases binaural dilation and restrictive pattern. Conclusions: our patients were similar to those described in the specialized literature. Echocardiogram is still the best study for the diagnosis and the use of functional measurements as Doppler imaging can help to reveal early diastolic failure. In our country the heart transplant is just feasible; mortality remains 100%. Keywords: Restrictive cardiomyopathy, Heart failure, Cardiomyopathy.

  20. Joint Venture Structuring in Restricted Industries

    Institute of Scientific and Technical Information of China (English)

    CHRIS; DEVONSHIRE-ELLIS

    2008-01-01

    When investing in China’s restricted in- dustries, it is essential to have a joint venture (JV) partner. Often the maximum percent- age of equity allowed in foreign ownership can only be 50 percent. So what options are available to the foreign investor to mitigate the risk of not owning, on paper, a majority

  1. 38 CFR 1.462 - Confidentiality restrictions.

    Science.gov (United States)

    2010-07-01

    ... Drug Abuse, Alcoholism Or Alcohol Abuse, Infection with the Human Immunodeficiency Virus (hiv), Or....460 through 1.499 of this part apply may be disclosed or used only as permitted by these regulations...) Unconditional compliance required. The restrictions on disclosure and use in §§ 1.460 through 1.499 of this...

  2. Optimal Policy under Restricted Government Spending

    DEFF Research Database (Denmark)

    Sørensen, Anders

    2006-01-01

    Welfare ranking of policy instruments is addressed in a two-sector Ramsey model with monopoly pricing in one sector as the only distortion. When government spending is restricted, i.e. when a government is unable or unwilling to finance the required costs for implementing the optimum policy...

  3. 50 CFR 16.3 - General restrictions.

    Science.gov (United States)

    2010-10-01

    ... INJURIOUS WILDLIFE Introduction § 16.3 General restrictions. Any importation or transportation of live... and welfare of human beings, to the interest of forestry, agriculture, and horticulture, and to the... into or the transportation of live wildlife or eggs thereof between the continental United States,...

  4. Material and Cultural Restriction of Political Life

    Institute of Scientific and Technical Information of China (English)

    马国祥

    2015-01-01

    Material and culture have a certain influence on the political life. In general, the higher level of economic development of the country, people's political life is more democratic. Culture has some negative effect on the political life. China's traditional cul-ture has restricted the people's political life in some ways.

  5. Restrictive dermopathy - Report of 12 cases

    NARCIS (Netherlands)

    Smitt, JHS; van Asperen, CJ; Niessen, CM; Beemer, FA; van Essen, AJ; Hulsmans, RFHJ; Oranje, AP; Steijlen, PM; Wesby-van Swaay, E; Tamminga, P; Breslau-Siderius, EJ

    1998-01-01

    Background: This study describes 12 cases of restrictive dermopathy seen during a period of 8 years by the Dutch Task Force on Genodermatology. We present these unique consecutive cases to provide more insight into the clinical picture and pathogenesis of the disease. Observations: Clinical features

  6. Restricted total stability and total attractivity

    Directory of Open Access Journals (Sweden)

    Giuseppe Zappala'

    2006-08-01

    Full Text Available In this paper the new concepts of restricted total stability and total attractivity is formulated. For this purpose the classical theory of Malkin with suitable changes and the theory of limiting equations, introduced by Sell developed by Artstein and Andreev, are used. Significant examples are presented.

  7. A role for autophagy in the extension of lifespan by dietary restriction in C. elegans.

    Directory of Open Access Journals (Sweden)

    Malene Hansen

    2008-02-01

    Full Text Available In many organisms, dietary restriction appears to extend lifespan, at least in part, by down-regulating the nutrient-sensor TOR (Target Of Rapamycin. TOR inhibition elicits autophagy, the large-scale recycling of cytoplasmic macromolecules and organelles. In this study, we asked whether autophagy might contribute to the lifespan extension induced by dietary restriction in C. elegans. We find that dietary restriction and TOR inhibition produce an autophagic phenotype and that inhibiting genes required for autophagy prevents dietary restriction and TOR inhibition from extending lifespan. The longevity response to dietary restriction in C. elegans requires the PHA-4 transcription factor. We find that the autophagic response to dietary restriction also requires PHA-4 activity, indicating that autophagy is a transcriptionally regulated response to food limitation. In spite of the rejuvenating effect that autophagy is predicted to have on cells, our findings suggest that autophagy is not sufficient to extend lifespan. Long-lived daf-2 insulin/IGF-1 receptor mutants require both autophagy and the transcription factor DAF-16/FOXO for their longevity, but we find that autophagy takes place in the absence of DAF-16. Perhaps autophagy is not sufficient for lifespan extension because although it provides raw material for new macromolecular synthesis, DAF-16/FOXO must program the cells to recycle this raw material into cell-protective longevity proteins.

  8. 50 CFR 622.45 - Restrictions on sale/purchase.

    Science.gov (United States)

    2010-10-01

    ... 50 Wildlife and Fisheries 8 2010-10-01 2010-10-01 false Restrictions on sale/purchase. 622.45... Management Measures § 622.45 Restrictions on sale/purchase. In addition to restrictions on sale/purchase related to closures, as specified in § 622.43 (a) and (b), restrictions on sale and/or purchase apply...

  9. 7 CFR 322.28 - General requirements; restricted articles.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 5 2010-01-01 2010-01-01 false General requirements; restricted articles. 322.28... EQUIPMENT Importation and Transit of Restricted Articles § 322.28 General requirements; restricted articles. (a) The following articles from any region are restricted articles: (1) Dead bees of any genus;...

  10. 7 CFR 319.75-2 - Restricted articles. 1

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 5 2010-01-01 2010-01-01 false Restricted articles. 1 319.75-2 Section 319.75-2... SERVICE, DEPARTMENT OF AGRICULTURE FOREIGN QUARANTINE NOTICES Khapra Beetle § 319.75-2 Restricted articles. 1 1 The importation of restricted articles may be subject to prohibitions or restrictions...

  11. Calorie restriction increases muscle mitochondrial biogenesis in healthy humans.

    Directory of Open Access Journals (Sweden)

    Anthony E Civitarese

    2007-03-01

    Full Text Available BACKGROUND: Caloric restriction without malnutrition extends life span in a range of organisms including insects and mammals and lowers free radical production by the mitochondria. However, the mechanism responsible for this adaptation are poorly understood. METHODS AND FINDINGS: The current study was undertaken to examine muscle mitochondrial bioenergetics in response to caloric restriction alone or in combination with exercise in 36 young (36.8 +/- 1.0 y, overweight (body mass index, 27.8 +/- 0.7 kg/m(2 individuals randomized into one of three groups for a 6-mo intervention: Control, 100% of energy requirements; CR, 25% caloric restriction; and CREX, caloric restriction with exercise (CREX, 12.5% CR + 12.5% increased energy expenditure (EE. In the controls, 24-h EE was unchanged, but in CR and CREX it was significantly reduced from baseline even after adjustment for the loss of metabolic mass (CR, -135 +/- 42 kcal/d, p = 0.002 and CREX, -117 +/- 52 kcal/d, p = 0.008. Participants in the CR and CREX groups had increased expression of genes encoding proteins involved in mitochondrial function such as PPARGC1A, TFAM, eNOS, SIRT1, and PARL (all, p < 0.05. In parallel, mitochondrial DNA content increased by 35% +/- 5% in the CR group (p = 0.005 and 21% +/- 4% in the CREX group (p < 0.004, with no change in the control group (2% +/- 2%. However, the activity of key mitochondrial enzymes of the TCA (tricarboxylic acid cycle (citrate synthase, beta-oxidation (beta-hydroxyacyl-CoA dehydrogenase, and electron transport chain (cytochrome C oxidase II was unchanged. DNA damage was reduced from baseline in the CR (-0.56 +/- 0.11 arbitrary units, p = 0.003 and CREX (-0.45 +/- 0.12 arbitrary units, p = 0.011, but not in the controls. In primary cultures of human myotubes, a nitric oxide donor (mimicking eNOS signaling induced mitochondrial biogenesis but failed to induce SIRT1 protein expression, suggesting that additional factors may regulate SIRT1 content

  12. Restriction of dairy products: a reality in inflammatory bowel disease patients

    Directory of Open Access Journals (Sweden)

    Mirella Brasil Lopes

    2014-03-01

    Full Text Available Introduction: Calcium deficiency is considered a risk factor for the development of osteoporosis in inflammatory bowel disease (IBD patients. Various dietary restrictions, including milk products are reported by these patients. Objective: To evaluate dairy product and dietary calcium intake by IBD patients. Methods: This cross-sectional study enrolled 65 outpatients with IBD recruited from one reference center for IBD. A semi-structured questionnaire (to collect demographic, socioeconomic and clinical data and a quantitative food frequency questionnaire were administered. With regard to clinical data, we evaluated the anthropometric nutritional status, the disease classification, the disease activity index and the presence of gastrointestinal symptoms. Selfreported modifications in the use of dairy products were evaluated. Results: The IBD patients´ ages ranged from 20-75 years and 67.0% were diagnosed with ulcerative colitis. The majority (64.7% reported restricting dairy products. The frequency of gastrointestinal symptoms was higher among the Crohn´s disease patients who restricted dairy products than among those with no restrictions (100% vs 42.9%; p = 0.013; this result was not observed among the UC (ulcerative colitis patients. Disease activity was also more frequent in the IBD patients who restricted dairy products than in those with no restrictions (23.8% vs 4.5%; p = 0.031, and among the UC patients, extensive disease was more common in the patients who restricted dairy products than in those with no restrictions (42.9% vs 20.0%; p = 0.03. Conclusion: Restricting dairy products is common among IBD patients, possibly due to disease activity, the presence of gastrointestinal symptoms and the extension of the disease.

  13. Effects of the Post-Olympics Driving Restrictions on Air Quality in Beijing

    Directory of Open Access Journals (Sweden)

    Hua Ma

    2016-09-01

    Full Text Available To reduce congestion and air pollution, 20% driving restriction, a license plate-based traffic control measure, has been implemented in Beijing since October 2008. While the long-term impacts of this policy remain controversial, it is important to understand how and why the policy effects of driving restrictions change over time. In this paper, the short- and long-run effects of the 20% driving restrictions in Beijing and the key factors shaping the effects are analyzed using daily PM10 pollution data. The results showed that in the short run, 20% driving restriction could effectively reduce ambient PM10 levels. However, this positive effect rapidly faded away within a year due to long-term behavioral responses of residents. A modified 20% restriction, designed to replace the original 20% restriction system since April 2009, which is less stringent and provides more possibility for intertemporal driving substitution, has shown some positive influence on air quality over the long run comparing with that under the original policy design. Temporarily, the more stringent the driving restriction was, the better effects it would have on air quality. In the long-run, however, the policy was likely to cause a vicious circle, and more stringent policy might induce stronger negative incentives which would result in even worse policy effects. Lessons learned from study of the effects of driving restrictions in Beijing will help other major cities in China and abroad to use driving restrictions more prudently and effectively in the future. Decision-makers should carefully consider the pros and cons of a transport policy and conduct the ex-ante and ex-post evaluations on it.

  14. Programmable DNA-Guided Artificial Restriction Enzymes.

    Science.gov (United States)

    Enghiad, Behnam; Zhao, Huimin

    2017-02-06

    Restriction enzymes are essential tools for recombinant DNA technology that have revolutionized modern biological research. However, they have limited sequence specificity and availability. Here we report a Pyrococcus furiosus Argonaute (PfAgo) based platform for generating artificial restriction enzymes (AREs) capable of recognizing and cleaving DNA sequences at virtually any arbitrary site and generating defined sticky ends of varying length. Short DNA guides are used to direct PfAgo to target sites for cleavage at high temperatures (>87 °C) followed by reannealing of the cleaved single stranded DNAs. We used this platform to generate over 18 AREs for DNA fingerprinting and molecular cloning of PCR-amplified or genomic DNAs. These AREs work as efficiently as their naturally occurring counterparts, and some of them even do not have any naturally occurring counterparts, demonstrating easy programmability, generality, versatility, and high efficiency for this new technology.

  15. Affective tone of mothers' statements to restrict their children's eating.

    Science.gov (United States)

    Pesch, Megan H; Miller, Alison L; Appugliese, Danielle P; Rosenblum, Katherine L; Lumeng, Julie C

    2016-08-01

    Maternal restrictive feeding behaviors have been associated with child weight status. The affective tone of mothers' statements intended to restrict their children's eating has not been examined. The objectives of this study were to describe the affective tone of mothers' restrictive feeding behaviors (positive or negative), and to test the association of child and mother characteristics with rates of Restriction with Positive Affect, Restriction with Negative Affect and Total Restriction. A total of 237 low-income child-mother dyads (mean child age 5.9 years) participated in a videotaped standardized laboratory eating protocol, during which mothers and children were both presented with large servings of cupcakes. A coding scheme was developed to count each restrictive statement with a positive affective tone and each restrictive statement with a negative affective tone. To establish reliability, 20% of videos were double-coded. Demographics and anthropometrics were obtained. Poisson regression models were used to test the association between characteristics of the child and mother with counts of Restriction with Positive Affect, Restriction with Negative Affect, and Total Restriction. Higher rates of Restriction with Positive Affect and Total Restriction were predicted by child obese weight status, and mother non-Hispanic white race/ethnicity. Higher rates of Restriction with Negative Affect were predicted by older child age, child obese weight status, mother non-Hispanic white race/ethnicity, and lower mother education level. In conclusion, in this study mothers of obese (vs. non-obese) children had higher rates of restriction in general, but particularly higher rates of Restriction with Negative Affect. Rather than being told not to restrict, mothers may need guidance on how to sensitively restrict their child's intake. Future studies should consider the contributions of maternal affect to children's responses to maternal restriction.

  16. Beyond Intergovernmentalism: The Europeanization of Restrictive Measures?

    Directory of Open Access Journals (Sweden)

    Francesco Giumelli

    2013-07-01

    Full Text Available The functioning of the European Union (EU has been explored extensively in recent years. The dominant prism through which to look at the EU is still one of locus: i.e. whether decisions are made in the capitals of its member states or in Brussels. This debate is contained in the dualism between intergovernmentalism and supranationalism, but drawing the boundaries between the two concepts is still undone. This article attempts to contribute to solving this problem by investigating the restrictive measures policy of the EU in order to identify three conditions under which intergovernmentalism should be used. First, when EU institutions are dependent on EU member states for information and expertise; second, when decision-making powers rest mainly in EU capitals; and three, when there are no exclusive fora for decision-making in Brussels. The study of the restrictive measures of the European Union does not meet any of these three conditions; therefore the article argues that the concept of supranational intergovernmentalism offers useful insights to understand the EU security governance of CFSP sanctions. The article is divided into four parts. The first introduces the debate on security governance and justifies the selection of this specific approach to the study of sanctions. The second part presents the restrictive measures policy of the European Union and justifies its pertinence to the field of security. The third part of the article investigates the emerging patterns in security governance by testing the three conditions on the decision-making process for EU restrictive measures. Finally, the conclusion summarises the main argument and indicates ways forward in the study of EU sanctions from a governance perspective.

  17. Restricted Conformal Property of Compressive Sensing

    OpenAIRE

    Cheng, Tao

    2014-01-01

    Energy and direction are tow basic properties of a vector. A discrete signal is a vector in nature. RIP of compressive sensing can not show the direction information of a signal but show the energy information of a signal. Hence, RIP is not complete. Orthogonal matrices can preserve angles and lengths. Preservation of length can show energies of signals like RIP do; and preservation of angle can show directions of signals. Therefore, Restricted Conformal Property (RCP) is proposed according t...

  18. Restriction endonucleases digesting DNA in PCR buffer

    Institute of Scientific and Technical Information of China (English)

    LIU Xue-dong; ZHENG Dong; ZHOU Yan-na; MAO Wei-wei; MA Jian-zhang

    2005-01-01

    Six commonly used restriction endonucleases (Res) (Acc I, Ban II, EcoR I, Hind III, Sac I, Sca I) were tested for their ability to directly digest DNA completely in the Polymerase Chain Reaction (PCR) buffers. The results showed that: with the requirement for additional magnesium supplemented as activator, Res, except EcoR I appeared star activity, completely digested unmethylated lambda DNA after overnight incubation in PCR buffer and functioned as equally well as in recommended Restriction Enzyme Buffer provided with each enzyme; all Res tested completely digested PCR products in PCR buffer, it implied digestion of PCR products may often be performed directly in the PCR tube without the requirement for any precipitation or purification steps; and the concentration of MgCl2 from 2.5 mmol·L-1 to 10 mmol·L-1 did not significantly affect activity of Res in PCR buffer. This simplified method for RE digestion of PCR products could have applications in restriction fragment length polymorphism (RFLP) analysis and single-stranded conformational polymorphism (SSCP) analysis of large PCR products. However, usage of this procedure for cloning applications needs further data.

  19. Team Formation and Communication Restrictions in Collectives

    Science.gov (United States)

    Agogino, Adrian K.; Turner, Kagan

    2003-01-01

    A collective of agents often needs to maximize a "world utility" function which rates the performance of an entire system, while subject to communication restrictions among the agents. Such communication restrictions make it difficult for agents which try to pursue their own "private" utilities to take actions that also help optimize the world utility. Team formation presents a solution to this problem, where by joining other agents, an agent can significantly increase its knowledge about the environment and improve its chances of both optimizing its own utility and that its doing so will contribute to the world utility. In this article we show how utilities that have been previously shown to be effective in collectives can be modified to be more effective in domains with moderate communication restrictions resulting in performance improvements of up to 75%. Additionally we show that even severe communication constraints can be overcome by forming teams where each agent of a team shares the same utility, increasing performance an additional 25%. We show that utilities and team sizes can be manipulated to form the best compromise between how "aligned" an agent s utility is with the world utility and how easily an agent can learn that utility.

  20. Type I restriction enzymes and their relatives.

    Science.gov (United States)

    Loenen, Wil A M; Dryden, David T F; Raleigh, Elisabeth A; Wilson, Geoffrey G

    2014-01-01

    Type I restriction enzymes (REases) are large pentameric proteins with separate restriction (R), methylation (M) and DNA sequence-recognition (S) subunits. They were the first REases to be discovered and purified, but unlike the enormously useful Type II REases, they have yet to find a place in the enzymatic toolbox of molecular biologists. Type I enzymes have been difficult to characterize, but this is changing as genome analysis reveals their genes, and methylome analysis reveals their recognition sequences. Several Type I REases have been studied in detail and what has been learned about them invites greater attention. In this article, we discuss aspects of the biochemistry, biology and regulation of Type I REases, and of the mechanisms that bacteriophages and plasmids have evolved to evade them. Type I REases have a remarkable ability to change sequence specificity by domain shuffling and rearrangements. We summarize the classic experiments and observations that led to this discovery, and we discuss how this ability depends on the modular organizations of the enzymes and of their S subunits. Finally, we describe examples of Type II restriction-modification systems that have features in common with Type I enzymes, with emphasis on the varied Type IIG enzymes.

  1. Emergency building temperature restrictions. Final evaluation

    Energy Technology Data Exchange (ETDEWEB)

    None

    1980-11-01

    On July 5, 1979, DOE promulgated final regulations of the Emergency Building Temperature Restrictions program, placing emergency restrictions on thermostat settings for space heating, space cooling, and hot water in commercial, industrial, and nonresidential public buildings. The final regulations restricted space heating to a maximum of 65/sup 0/F, hot water temperature to a maximum of 105/sup 0/F, and cooling temperature to a minimum of 78/sup 0/F. A comprehensive evaluation of the entire EBTF program for a nine-month period from July 16, 1979 is presented. In Chapter 1, an estimate of the population of buildings covered by EBTR is presented. In Chapter 2, EBTR compliance by building type and region is reported. Exemptions are also discussed. In Chapter 3, the simulations of building energy use are explained and the relative impact of various building characteristics and effectiveness of different control strategies are estimated. Finally, in Chapter 4, the methodology for scaling the individual building energy savings to the national level is described, and estimated national energy savings are presented.

  2. Food restriction modifies ultrastructure of hippocampal synapses.

    Science.gov (United States)

    Babits, Réka; Szőke, Balázs; Sótonyi, Péter; Rácz, Bence

    2016-04-01

    Consumption of high-energy diets may compromise health and may also impair cognition; these impairments have been linked to tasks that require hippocampal function. Conversely, food restriction has been shown to improve certain aspects of hippocampal function, including spatial memory and memory persistence. These diet-dependent functional changes raise the possibility that the synaptic structure underlying hippocampal function is also affected. To examine how short-term food restriction (FR) alters the synaptic structure of the hippocampus, we used quantitative electron microscopy to analyze the organization of neuropil in the CA1 stratum radiatum of the hippocampus in young rats, consequent to reduced food. While four weeks of FR did not modify the density, size, or shape of postsynaptic spines, the synapses established by these spines were altered, displaying increased mean length, and more frequent perforations of postsynaptic densities. That the number of perforated synapses (believed to be an indicator of synaptic enhancement) increased, and that the CA1 spine population had on average significantly longer PSDs suggests that synaptic efficacy of axospinous synapses also increased in the CA1. Taken together, our ultrastructural data reveal previously unrecognized structural changes at hippocampal synapses as a function of food restriction, supporting a link between metabolic balance and synaptic plasticity.

  3. Interactions between HIV-1 Vif and human ElonginB-ElonginC are important for CBF-β binding to Vif

    OpenAIRE

    Wang, Xiaodan; Wang, Xiaoying; Zhang, Haihong; Lv, Mingyu; Zuo, Tao; Wu, Hui; Wang, Jiawen; Liu, Donglai; Wang, Chu; ZHANG, Jingyao; Li, Xu; Wu, Jiaxin; Yu, Bin; Kong, Wei; Yu, Xianghui

    2013-01-01

    Background The HIV-1 accessory factor Vif is necessary for efficient viral infection in non-permissive cells. Vif antagonizes the antiviral activity of human cytidine deaminase APOBEC3 proteins that confer the non-permissive phenotype by tethering them (APOBEC3DE/3F/3G) to the Vif-CBF-β-ElonginB-ElonginC-Cullin5-Rbx (Vif-CBF-β-EloB-EloC-Cul5-Rbx) E3 complex to induce their proteasomal degradation. EloB and EloC were initially reported as positive regulatory subunits of the Elongin (SIII) comp...

  4. Histopathological aspects of liver under variable food restriction: has the intense one-week food restriction a protective effect on non-alcoholic-fatty-liver-disease (NAFLD) development?

    Science.gov (United States)

    Makovicky, Peter; Tumova, Eva; Volek, Zdenek; Makovicky, Pavol; Vodickova, Ludmila; Slyskova, Jana; Svoboda, Miroslav; Rejhova, Alexandra; Vodicka, Pavel; Samasca, Gabriel; Kralova, Alena; Nagy, Melinda; Mydlarova-Blascakova, Marta; Poracova, Jana

    2014-12-01

    Non-alcoholic-fatty-liver-disease (NAFLD) is a clinicopathologic entity characterized by a variety of hepatic injury patterns without significant alcohol use. It has a close association with obesity, so treatment includes weight loss, control of insulin sensitivity, interventions directed at inflammation and fibrosis. There is a certain relationship between the grade and duration of food restriction and hepatic function. The objective of this work was to describe the relationship between biochemistry, autoantibodies, insulin-like growth factor I (IGF-I), insulin-like growth factor binding protein 3 (IGFBP-3), and liver morphology in experimental rabbit groups with food restriction as compared to controls with ad libitum food (ADL) income. The experiment was performed on a total of 24 rabbits of a weaning age of 25-81 days. The first group (R1) was restricted between 32 and 39 days of age to 50 g of food per rabbit a day. The second group (R2) was also restricted between 32 and 39 days, but the rabbits received 65 g of food per rabbit a day. At the end of the experiment, the blood and liver samples were collected at necropsy. NAFLD has developed in all three groups. There was any autoantibody positivity in all three groups. IGF-I is moderately higher in R1 and R2 group, as compared to the control group (P > 0.05). IGFBP-3 is without statistical significance in all three groups. Alkaline phosphatase (ALP) is the only liver biochemical parameter that has significantly increased following food restriction (P > 0.039). Single one-week restriction has any protective effect on NAFLD development.

  5. Carbohydrate restriction improves the features of Metabolic Syndrome. Metabolic Syndrome may be defined by the response to carbohydrate restriction

    Directory of Open Access Journals (Sweden)

    Feinman Richard D

    2005-11-01

    conclusion is probably not surprising but has not been explicitly stated before. The known effects of CHO-induced hypertriglyceridemia, the HDL-lowering effect of low fat, high CHO interventions and the obvious improvement in glucose and insulin from CHO restriction should have made this evident. In addition, recent studies suggest that a subset of MetS, the ratio of TAG/HDL, is a good marker for insulin resistance and risk of CVD, and this indicator is reliably reduced by CHO restriction and exacerbated by high CHO intake. Inability to make this connection in the past has probably been due to the fact that individual responses have been studied in isolation as well as to the emphasis of traditional therapeutic approaches on low fat rather than low CHO. We emphasize that MetS is not a disease but a collection of markers. Individual physicians must decide whether high LDL, or other risk factors are more important than the features of MetS in any individual case but if MetS is to be considered it should be recognized that reducing CHO will bring improvement. Response of symptoms to CHO restriction might thus provide a new experimental criterion for MetS in the face of on-going controversy about a useful definition. As a guide to future research, the idea that control of insulin metabolism by CHO intake is, to a first approximation, the underlying mechanism in MetS is a testable hypothesis.

  6. Carbohydrate restriction improves the features of Metabolic Syndrome. Metabolic Syndrome may be defined by the response to carbohydrate restriction.

    Science.gov (United States)

    Volek, Jeff S; Feinman, Richard D

    2005-11-16

    surprising but has not been explicitly stated before. The known effects of CHO-induced hypertriglyceridemia, the HDL-lowering effect of low fat, high CHO interventions and the obvious improvement in glucose and insulin from CHO restriction should have made this evident. In addition, recent studies suggest that a subset of MetS, the ratio of TAG/HDL, is a good marker for insulin resistance and risk of CVD, and this indicator is reliably reduced by CHO restriction and exacerbated by high CHO intake. Inability to make this connection in the past has probably been due to the fact that individual responses have been studied in isolation as well as to the emphasis of traditional therapeutic approaches on low fat rather than low CHO. We emphasize that MetS is not a disease but a collection of markers. Individual physicians must decide whether high LDL, or other risk factors are more important than the features of MetS in any individual case but if MetS is to be considered it should be recognized that reducing CHO will bring improvement. Response of symptoms to CHO restriction might thus provide a new experimental criterion for MetS in the face of on-going controversy about a useful definition. As a guide to future research, the idea that control of insulin metabolism by CHO intake is, to a first approximation, the underlying mechanism in MetS is a testable hypothesis.

  7. Moderate maternal food restriction in mice impairs physical growth, behavior, and neurodevelopment of offspring.

    Science.gov (United States)

    Akitake, Yoshiharu; Katsuragi, Shinji; Hosokawa, Masato; Mishima, Kenichi; Ikeda, Tomoaki; Miyazato, Mikiya; Hosoda, Hiroshi

    2015-01-01

    Intrauterine growth retardation (IUGR) occurs in 3% to 7% of all pregnancies. Recent human studies have indicated that neurodevelopmental disabilities, learning disorders, memory impairment, and mood disturbance are common in IUGR offspring. However, the interactions between IUGR and neurodevelopmental disorders are unclear because of the wide range of causes of IUGR, such as maternal malnutrition, placental insufficiency, pregnancy toxemia, and fetal malformations. Meanwhile, many studies have shown that moderate food restriction enhances spatial learning and improves mood disturbance in adult humans and animals. To date, the effects of maternal moderate food restriction on fetal brain remain largely unknown. In this study, we hypothesized that IUGR would be caused by even moderate food restriction in pregnant females and that the offspring would have neurodevelopmental disabilities. Mid-pregnant mice received moderate food restriction through the early lactation period. The offspring were tested for aspects of physical development, behavior, and neurodevelopment. The results showed that moderate maternal food restriction induced IUGR. Offspring had low birth weight and delayed development of physical and coordinated movement. Moreover, IUGR offspring exhibited mental disabilities such as anxiety and poor cognitive function. In particular, male offspring exhibited significantly impaired cognitive function at 3 weeks of age. These results suggested that a restricted maternal diet could be a risk factor for developmental disability in IUGR offspring and that male offspring might be especially susceptible.

  8. Alternatives to restrictive feeding practices to promote self-regulation in childhood: a developmental perspective.

    Science.gov (United States)

    Rollins, B Y; Savage, J S; Fisher, J O; Birch, L L

    2016-10-01

    Intake of energy-dense snack foods is high among US children. Although the use of restrictive feeding practices has been shown to be counterproductive, there is very limited evidence for effective alternatives to restriction that help children moderate their intake of these foods and that facilitate the development of self-regulation in childhood. The developmental literature on parenting and child outcomes may provide insights into alternatives to restrictive feeding practices. This review paper uses a model of parental control from the child development and parenting literatures to (i) operationally define restrictive feeding practices; (ii) summarize current evidence for antecedents and effects of parental restriction use on children's eating behaviours and weight status, and (iii) highlight alternative feeding practices that may facilitate the development of children's self-regulation and moderate children's intake of palatable snack foods. We also discuss recent empirical evidence highlighting the role of child temperament and food motivation related behaviours as factors that prompt parents to use restrictive feeding practices and, yet, may increase children's dysregulated intake of forbidden foods.

  9. FACTORS INFLUENCING THE EVOLUTION OF YOUTH TRAVEL

    Directory of Open Access Journals (Sweden)

    Student Claudia MOISĂ

    2010-01-01

    Full Text Available Youth travel is an important part of global tourism, consequently, getting to know the evolution of this form of tourism requires an approach of the aspects regarding the permissive and restrictive factors that influence the youth travel dynamic worldwide. In terms of the factors that influence youth travel, we highlighted these two categories of factors (permissive and restrictive and, within each category, we tried to singularize the influence of every factor over youth travel.

  10. Controlling the enzymatic activity of a restriction enzyme by light.

    Science.gov (United States)

    Schierling, Benno; Noël, Ann-Josée; Wende, Wolfgang; Hien, Le Thi; Volkov, Eugeny; Kubareva, Elena; Oretskaya, Tatiana; Kokkinidis, Michael; Römpp, Andreas; Spengler, Bernhard; Pingoud, Alfred

    2010-01-26

    For many applications it would be desirable to be able to control the activity of proteins by using an external signal. In the present study, we have explored the possibility of modulating the activity of a restriction enzyme with light. By cross-linking two suitably located cysteine residues with a bifunctional azobenzene derivative, which can adopt a cis- or trans-configuration when illuminated by UV or blue light, respectively, enzymatic activity can be controlled in a reversible manner. To determine which residues when cross-linked show the largest "photoswitch effect," i.e., difference in activity when illuminated with UV vs. blue light, > 30 variants of a single-chain version of the restriction endonuclease PvuII were produced, modified with azobenzene, and tested for DNA cleavage activity. In general, introducing single cross-links in the enzyme leads to only small effects, whereas with multiple cross-links and additional mutations larger effects are observed. Some of the modified variants, which carry the cross-links close to the catalytic center, can be modulated in their DNA cleavage activity by a factor of up to 16 by illumination with UV (azobenzene in cis) and blue light (azobenzene in trans), respectively. The change in activity is achieved in seconds, is fully reversible, and, in the case analyzed, is due to a change in V(max) rather than K(m).

  11. Vif Proteins from Diverse Human Immunodeficiency Virus/Simian Immunodeficiency Virus Lineages Have Distinct Binding Sites in A3C.

    Science.gov (United States)

    Zhang, Zeli; Gu, Qinyong; Jaguva Vasudevan, Ananda Ayyappan; Jeyaraj, Manimehalai; Schmidt, Stanislaw; Zielonka, Jörg; Perković, Mario; Heckel, Jens-Ove; Cichutek, Klaus; Häussinger, Dieter; Smits, Sander H J; Münk, Carsten

    2016-11-15

    Lentiviruses have evolved the Vif protein to counteract APOBEC3 (A3) restriction factors by targeting them for proteasomal degradation. Previous studies have identified important residues in the interface of human immunodeficiency virus type 1 (HIV-1) Vif and human APOBEC3C (hA3C) or human APOBEC3F (hA3F). However, the interaction between primate A3C proteins and HIV-1 Vif or natural HIV-1 Vif variants is still poorly understood. Here, we report that HIV-1 Vif is inactive against A3Cs of rhesus macaques (rhA3C), sooty mangabey monkeys (smmA3C), and African green monkeys (agmA3C), while HIV-2, African green monkey simian immunodeficiency virus (SIVagm), and SIVmac Vif proteins efficiently mediate the depletion of all tested A3Cs. We identified that residues N/H130 and Q133 in rhA3C and smmA3C are determinants for this HIV-1 Vif-triggered counteraction. We also found that the HIV-1 Vif interaction sites in helix 4 of hA3C and hA3F differ. Vif alleles from diverse HIV-1 subtypes were tested for degradation activities related to hA3C. The subtype F-1 Vif was identified to be inactive for degradation of hA3C and hA3F. The residues that determined F-1 Vif inactivity in the degradation of A3C/A3F were located in the C-terminal region (K167 and D182). Structural analysis of F-1 Vif revealed that impairing the internal salt bridge of E171-K167 restored reduction capacities to A3C/A3F. Furthermore, we found that D101 could also form an internal interaction with K167. Replacing D101 with glycine and R167 with lysine in NL4-3 Vif impaired its counteractivity to A3F and A3C. This finding indicates that internal interactions outside the A3 binding region in HIV-1 Vif influence the capacity to induce degradation of A3C/A3F.

  12. Age-Related Differences in Restricted Repetitive Behaviors in Autism Spectrum Disorders

    Science.gov (United States)

    Esbensen, Anna J.; Seltzer, Marsha Mailick; Lam, Kristen S. L.; Bodfish, James W.

    2009-01-01

    Restricted repetitive behaviors (RRBs) were examined in a large group of children, adolescents and adults with ASD in order to describe age-related patterns of symptom change and association with specific contextual factors, and to examine if the patterns of change are different for the various types of RRBs. Over 700 individuals with ASD were…

  13. Effects of moderate energy restriction on physical performance and substrate utilization in non-obese men

    NARCIS (Netherlands)

    Velthuis-te Wierik, E.J.M.; Hoogzaad, L.V.; Berg, H. van den; Schaafsma, G.

    1994-01-01

    Energy restriction (ER) has shown to be an effective 'anti-aging' factor in rodents, resulting in an increased life span and preventing or delaying the occurrence of many age-related diseases in rodents. As a part of a feasibility study on the potential application of ER in humans, we studied the ef

  14. The Acquisition of English Restrictive Relative Clauses by Arab Adult EFL Learners

    Science.gov (United States)

    Alroudhan, Hayat Eid

    2016-01-01

    This study investigates the challenges faced by Arab adult learners of English as a foreign language (EFL) in acquiring English restrictive relative clauses (RRCs), as well as the factors that affect the process of acquisition. This issue has received considerable attention in second language (L2) research. The present study discusses the…

  15. Restrictive pattern on spirometry: association with cardiovascular risk and level of physical activity in asymptomatic adults

    Directory of Open Access Journals (Sweden)

    Evandro Fornias Sperandio

    2016-02-01

    Full Text Available Objective : To determine whether a restrictive pattern on spirometry is associated with the level of physical activity in daily life (PADL, as well as with cardiovascular disease (CVD risk factors, in asymptomatic adults. Methods : A total of 374 participants (mean age, 41 ± 14 years underwent spirometry, which included the determination of FVC and FEV1. A restrictive pattern on spirometry was defined as an FEV1/FVC ratio > 0.7 and an FVC < 80% of the predicted value. After conducting demographic, anthropometric, and CVD risk assessments, we evaluated body composition, muscle function, and postural balance, as well as performing cardiopulmonary exercise testing and administering the six-minute walk test. The PADL was quantified with a triaxial accelerometer. Results : A restrictive pattern on spirometry was found in 10% of the subjects. After multivariate logistic regression, adjusted for confounders (PADL and cardiorespiratory fitness, the following variables retained significance (OR; 95% CI as predictors of a restrictive pattern: systemic arterial hypertension (17.5; 1.65-184.8, smoking (11.6; 1.56-87.5, physical inactivity (8.1; 1.43-46.4, larger center-of-pressure area while standing on a force platform (1.34; 1.05-1.71; and dyslipidemia (1.89; 1.12-1.98. Conclusions : A restrictive pattern on spirometry appears to be common in asymptomatic adults. We found that CVD risk factors, especially systemic arterial hypertension, smoking, and physical inactivity, were directly associated with a restrictive pattern, even when the analysis was adjusted for PADL and cardiorespiratory fitness. Longitudinal studies are needed in order to improve understanding of the etiology of a restrictive pattern as well as to aid in the design of preventive strategies.

  16. Restriction enzyme-mediated DNA family shuffling.

    Science.gov (United States)

    Behrendorff, James B Y H; Johnston, Wayne A; Gillam, Elizabeth M J

    2014-01-01

    DNA shuffling is an established recombinatorial method that was originally developed to increase the speed of directed evolution experiments beyond what could be accomplished using error-prone PCR alone. To achieve this, mutated copies of a protein-coding sequence are fragmented with DNase I and the fragments are then reassembled in a PCR without primers. The fragments anneal where there is sufficient sequence identity, resulting in full-length variants of the original gene that have inherited mutations from multiple templates. Subsequent studies demonstrated that directed evolution could be further accelerated by shuffling similar native protein-coding sequences from the same gene family, rather than mutated variants of a single gene. Generally at least 65-75 % global identity between parental sequences is required in DNA family shuffling, with recombination mostly occurring at sites with at least five consecutive nucleotides of local identity. Since DNA shuffling was originally developed, many variations on the method have been published. In particular, the use of restriction enzymes in the fragmentation step allows for greater customization of fragment lengths than DNase I digestion and avoids the risk that parental sequences may be over-digested into unusable very small fragments. Restriction enzyme-mediated fragmentation also reduces the occurrence of undigested parental sequences that would otherwise reduce the number of unique variants in the resulting library. In the current chapter, we provide a brief overview of the alternative methods currently available for DNA shuffling as well as a protocol presented here that improves on several previous implementations of restriction enzyme-mediated DNA family shuffling, in particular with regard to purification of DNA fragments for reassembly.

  17. Approximate message passing with restricted Boltzmann machine priors

    Science.gov (United States)

    Tramel, Eric W.; Drémeau, Angélique; Krzakala, Florent

    2016-07-01

    Approximate message passing (AMP) has been shown to be an excellent statistical approach to signal inference and compressed sensing problems. The AMP framework provides modularity in the choice of signal prior; here we propose a hierarchical form of the Gauss-Bernoulli prior which utilizes a restricted Boltzmann machine (RBM) trained on the signal support to push reconstruction performance beyond that of simple i.i.d. priors for signals whose support can be well represented by a trained binary RBM. We present and analyze two methods of RBM factorization and demonstrate how these affect signal reconstruction performance within our proposed algorithm. Finally, using the MNIST handwritten digit dataset, we show experimentally that using an RBM allows AMP to approach oracle-support performance.

  18. Approximate Message Passing with Restricted Boltzmann Machine Priors

    CERN Document Server

    Tramel, Eric W; Krzakala, Florent

    2015-01-01

    Approximate Message Passing (AMP) has been shown to be an excellent statistical approach to signal inference and compressed sensing problem. The AMP framework provides modularity in the choice of signal prior; here we propose a hierarchical form of the Gauss-Bernouilli prior which utilizes a Restricted Boltzmann Machine (RBM) trained on the signal support to push reconstruction performance beyond that of simple iid priors for signals whose support can be well represented by a trained binary RBM. We present and analyze two methods of RBM factorization and demonstrate how these affect signal reconstruction performance within our proposed algorithm. Finally, using the MNIST handwritten digit dataset, we show experimentally that using an RBM allows AMP to approach oracle-support performance.

  19. A new restriction endonuclease from Spirulina platensis.

    OpenAIRE

    Kawamura, M; Sakakibara, M; Watanabe, T; Kita, K.; Hiraoka, N; Obayashi, A; Takagi, M; Yano, K

    1986-01-01

    Three restriction endonucleases, Sp1I, Sp1II and Sp1III have been purified partially from Spirulina platensis subspecies siamese and named. Sp1I cleaves bacteriophage lambda DNA at one site, phi X 174 RF DNA at two sites, but does not cleave pBR322 DNA. This enzyme recognizes the sequence 5'CGTACG3' 3'GCATCG5' and cuts the site indicated by the arrows. Sp1II is an isoschizomer of Tth111I and Sp1III is an isoschizomer of HaeIII.

  20. Restricted fish feeding reduces cod otolith opacity

    DEFF Research Database (Denmark)

    Høie, H.; Folkvord, A.; Mosegaard, Henrik

    2008-01-01

    The purpose of this work was to examine the effect of reduced feeding and constant temperature on cod otolith opacity. Three groups of juvenile cod were given restricted food rations at different times for 4 months, resulting in depressed somatic growth. Otolith opacity was measured on pictures...... in otolith opacity were found between individual fish both within groups and between groups. In two of the three groups significantly more translucent otolith material was deposited in response to reduced feeding. Our results show that variations in feeding and hence fish growth resulted in variation...

  1. The Monetary Policy – Restrictive or Expansive?

    Directory of Open Access Journals (Sweden)

    Adam Szafarczyk

    2007-10-01

    Full Text Available The monetary policy plays an important role in macroeconomic policy of government. There is a question concerning type of this policy expansive or restrictive (easy or tidy monetary policy. Unfortunately, we have a lot of criteria. Each of them gives us other answer. So due to equitation of Irving Fisher we have dominantly expansive monetary policy. This same situation exists when we use nominal value of rediscount interest rate of central bank. Opposite result appears when we use real value of this interest rate or level of obligatory reserve. Taking under consideration liquidity on money market we know, that level of interest rate is too high.

  2. A User-Friendly Method for Teaching Restriction Enzyme Mapping.

    Science.gov (United States)

    Ehrman, Patrick

    1990-01-01

    Presented is a teaching progression that enhances learning through low-cost, manipulative transparencies. Discussed is instruction about restriction enzymes, plasmids, cutting plasmids, plasmid maps, recording data, and mapping restriction sites. Mapping wheels for student use is included. (CW)

  3. Medical Expenditure Panel Survey (MEPS) Restricted Data Files

    Data.gov (United States)

    U.S. Department of Health & Human Services — Restricted Data Files Available at the Data Centers Researchers and users with approved research projects can access restricted data files that have not been...

  4. 48 CFR 552.203-71 - Restriction on Advertising.

    Science.gov (United States)

    2010-10-01

    ... 48 Federal Acquisition Regulations System 4 2010-10-01 2010-10-01 false Restriction on Advertising... Restriction on Advertising. As prescribed in 503.570-2, insert the following clause: Restriction on Advertising (SEP 1999) The Contractor shall not refer to this contract in commercial advertising or...

  5. 7 CFR 930.15 - Restricted percentage cherries.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 8 2010-01-01 2010-01-01 false Restricted percentage cherries. 930.15 Section 930.15... Agreements and Orders; Fruits, Vegetables, Nuts), DEPARTMENT OF AGRICULTURE TART CHERRIES GROWN IN THE STATES... Handling Definitions § 930.15 Restricted percentage cherries. Restricted percentage cherries means...

  6. 7 CFR 1724.8 - Restrictions on lobbying.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 11 2010-01-01 2010-01-01 false Restrictions on lobbying. 1724.8 Section 1724.8 Agriculture Regulations of the Department of Agriculture (Continued) RURAL UTILITIES SERVICE, DEPARTMENT OF... Restrictions on lobbying. Borrowers shall comply with the restrictions and requirements in connection...

  7. 14 CFR 1310.9 - Restrictions on lobbying.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 5 2010-01-01 2010-01-01 false Restrictions on lobbying. 1310.9 Section... CONDITION OF GUARANTEED LOAN § 1310.9 Restrictions on lobbying. (a) While the Board is not part of the... Restrictions on Lobbying”) of title 31 (“Money and Finance: Treasury”) of the Code of Federal Regulations...

  8. 7 CFR 1710.125 - Restrictions on lobbying.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 11 2010-01-01 2010-01-01 false Restrictions on lobbying. 1710.125 Section 1710.125... and Basic Policies § 1710.125 Restrictions on lobbying. Borrowers are required to comply with certain requirements with respect to restrictions on lobbying activities. See 7 CFR part 3018....

  9. 14 CFR 1274.929 - Restrictions on lobbying.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 5 2010-01-01 2010-01-01 false Restrictions on lobbying. 1274.929 Section... WITH COMMERCIAL FIRMS Other Provisions and Special Conditions § 1274.929 Restrictions on lobbying. Restrictions on Lobbying July 2002 This award is subject to the provisions of 14 CFR part 1271...

  10. 10 CFR 1016.34 - Accountability for Secret Restricted Data.

    Science.gov (United States)

    2010-01-01

    ... 10 Energy 4 2010-01-01 2010-01-01 false Accountability for Secret Restricted Data. 1016.34 Section... Information § 1016.34 Accountability for Secret Restricted Data. Each permittee possessing documents containing Secret Restricted Data shall establish a document accountability procedure and shall...

  11. Neural Correlates of Restricted, Repetitive Behaviors in Autism Spectrum Disorders

    Science.gov (United States)

    2014-12-01

    Restrictive Repetitive Behaviors in Autism Spectrum Disorder . Authors: T.Q.Nguyen, B...Manoach. Functional Connectivity of the Dorsal Anterior Cingulate Cortex Predicts Restrictive Repetitive Behaviors in Autism Spectrum Disorder We...Introduction: Although restricted , repetitive behaviors (RRBs) are a highly disabling core feature of Autism Spectrum Disorders (ASDs), they

  12. Intermittent′ restrictive ventricular septal defect in Tetralogy of Fallot

    Directory of Open Access Journals (Sweden)

    Sudhir S Shetkar

    2015-01-01

    Full Text Available Ventricular septal defect (VSD in Tetralogy of Fallot (TOF is usually large and non-restrictive with equalization of right and left ventricular pressures. Restrictive VSD in TOF is rare. We present an unusual case of TOF with restriction to VSD caused by accessory tricuspid valve tissue that varied with respiration.

  13. 36 CFR 13.1174 - Whale water restrictions.

    Science.gov (United States)

    2010-07-01

    ... 36 Parks, Forests, and Public Property 1 2010-07-01 2010-07-01 false Whale water restrictions. 13... Vessel Operating Restrictions § 13.1174 Whale water restrictions. (a) May 15 through September 30, the following waters are designated as whale waters. (1) Waters north of a line drawn from Point Carolus...

  14. Restrictions on autogressive error processes in systems of demand equations

    OpenAIRE

    Brown, Mark G.

    1993-01-01

    Alternative theoretically based restrictions on autoregressive error processes in systems of demand equations are examined. Scaling, translation, and a utility-based approach suggested by Theil are used to generate restrictions. A study of juice demands suggests that the restrictions examined may be useful for empirical analysis.

  15. Oncogenic pathways impinging on the G2-restriction point

    NARCIS (Netherlands)

    Foijer, F; Simonis, M; van Vliet, M; Wessels, L; Kerkhoven, R; Sorger, P K; Te Riele, H

    2008-01-01

    In the absence of mitogenic stimuli, cells normally arrest in G(1/0), because they fail to pass the G1-restriction point. However, abrogation of the G1-restriction point (by loss of the retinoblastoma gene family) reveals a second-restriction point that arrests cells in G2. Serum-starvation-induced

  16. 50 CFR 697.23 - Restricted gear areas.

    Science.gov (United States)

    2010-10-01

    ... 50 Wildlife and Fisheries 9 2010-10-01 2010-10-01 false Restricted gear areas. 697.23 Section 697... Measures § 697.23 Restricted gear areas. (a) Resolution of lobster gear conflicts with fisheries managed...) Restricted Gear Area I—(1) Duration—(i) Mobile Gear. From October 1 through June 15 of each fishing year,...

  17. 14 CFR 252.8 - Extent of smoking restrictions.

    Science.gov (United States)

    2010-01-01

    ... 14 Aeronautics and Space 4 2010-01-01 2010-01-01 false Extent of smoking restrictions. 252.8... PROCEEDINGS) ECONOMIC REGULATIONS SMOKING ABOARD AIRCRAFT § 252.8 Extent of smoking restrictions. The restrictions on smoking described in §§ 252.3 through 252.7 shall apply to all locations within the aircraft....

  18. Communication restriction in adults who stutter.

    Science.gov (United States)

    Lee, Amanda; Van Dulm, Ondene; Robb, Michael P; Ormond, Tika

    2015-07-01

    This study explored communication restriction in adults with stuttering (AWS) by means of typical language measures obtained using the Systematic Analysis of Language Transcripts - New Zealand (SALT-NZ) software, as well as systemic functional linguistics (SFL) analyses. The areas of language productivity and complexity, modality (i.e. linguistic politeness) and the language of appraisal were compared between AWS and typically fluent speakers (adults with no stuttering (AWNS)). Ten-minute conversational samples were obtained from 20 AWS and 20 age- and sex-matched AWNS. Transcripts were analysed for quantity and complexity of verbal output, and frequency of use of modality and appraisal resource subtypes. Means comparison and correlation analyses were conducted using grouped data. AWS produced less language and less complex language than AWNS, measured by SALT-NZ and SFL indices. AWS also differed from AWNS in their use of modality resources to express politeness - they produced fewer modal operators and more comment adjuncts than AWNS. A smaller proportion of their language expressed the explicit appreciation of things. The linguistic patterns identified in the conversational language of AWS suggested a reduced openness to interpersonal engagement within communication exchanges, which may restrict opportunities for and the experience of such exchanges. The value of SFL to this area of research is discussed.

  19. Calorie restriction-mediated replicative lifespan extension in yeast is non-cell autonomous.

    Directory of Open Access Journals (Sweden)

    Szu-Chieh Mei

    2015-01-01

    Full Text Available In laboratory yeast strains with Sir2 and Fob1 function, wild-type NAD+ salvage is required for calorie restriction (CR to extend replicative lifespan. CR does not significantly alter steady state levels of intracellular NAD+ metabolites. However, levels of Sir2 and Pnc1, two enzymes that sequentially convert NAD+ to nicotinic acid (NA, are up-regulated during CR. To test whether factors such as NA might be exported by glucose-restricted mother cells to survive later generations, we developed a replicative longevity paradigm in which mother cells are moved after 15 generations on defined media. The experiment reveals that CR mother cells lose the longevity benefit of CR when evacuated from their local environment to fresh CR media. Addition of NA or nicotinamide riboside (NR allows a moved mother to maintain replicative longevity despite the move. Moreover, conditioned medium from CR-treated cells transmits the longevity benefit of CR to moved mother cells. Evidence suggests the existence of a longevity factor that is dialyzable but is neither NA nor NR, and indicates that Sir2 is not required for the longevity factor to be produced or to act. Data indicate that the benefit of glucose-restriction is transmitted from cell to cell in budding yeast, suggesting that glucose restriction may benefit neighboring cells and not only an individual cell.

  20. [Effect of dosed diet restriction on physiological remodeling and bioelectric properties of bone].

    Science.gov (United States)

    Levashov, M I; Ianko, R V; Chaka, E G; Safonov, S L

    2014-07-01

    The effect of dosed diet restriction on the physiological remodeling and bioelectric properties of bone tissue was studied in 48 male Wistar rats 3- and 18-months of age. The rate of bone tissue apposition was studied by the dynamic histomorphometry method (intravital tetracycline labeling). Electric potentials on the periosteal surface of the freshly isolated femurs were recorded. The magnitude of dielectric loss factor was determined to assess the quality of bone tissue. The control rats received a standard diet. The experimental rats received a limited diet (60 % of the standard mass) for 28 days. The magnitude and rate of the bone tissue apposition on the endosteal and periosteal surface of the tibia were less by 38.4% and 122.7% respectively in experimental rats after dosed diet restriction. Electric potential in the metaphyseal-epiphyseal growth zones of the femur was 29.7% lower, and the dielectric loss factor increased by 15.8%. The bone tissue apposition rate and the electric potential magnitude were increased 10 days after completion of the dosed diet restriction. The magnitude of the dielectric loss factor decreased after returning to the standard diet. Key words: dosed diet restriction, bone, remodelling, bioelectric properties.

  1. 神经元限制性沉默因子在NTera2/CloneD1细胞向神经元分化模型中表达的检测%Detection of the Expression of Neuron-Restrictive Silencer Factor in the Model of Neuronal Differentiation from NTera2/CloneD1 Cells

    Institute of Scientific and Technical Information of China (English)

    张静; 裴雪涛; 王思涵; 张博文; 姚海雷; 陈琳; 吕洋; 南雪; 岳文; 李艳华

    2011-01-01

    目的:建立NTera2/CloneD1细胞向神经元分化的模型,检测神经元限制性沉默因子(NRSF)经分化培养基诱导后表达的变化.方法:收集正常培养的NTera2/CloneDl细胞及经全反武维甲酸(RA)、阿糖胞苷(AraC)、尿苷分阶段诱导共28 d的细胞,显微镜下观察诱导前后细胞的形态学变化;免疫荧光法检测NTera2/CloneD1细胞诱导前后干性标志Nestin、Sox2和成熟神经元特异性标志NF-200、β-tubulinⅢ的表达情况;应用RT-PCR和免疫荧光法对NRSF进行mRNA和蛋白水平的检测.结果:显微镜下观察到正常培养的NTera2/CloneD1细胞呈克隆样生长,经分化培养基诱导后的NTera2/CloneD1细胞表现出典型的神经元样细胞形态.免疫荧光检测表明,未诱导的NTera2/CloneD1细胞表达神经干细胞的标志Sox2、Nestin,不表达成熟神经元特异性蛋白NF-200、β-tubulinⅢ;而经RA等诱导分化的细胞则不表达Sox2、Nestin,表达NF-200、β-tubulinⅢ.RT-PCR和免疫荧光检测显示,NRSF在诱导分化后的NTera2/CloneD1细胞中的表达量显著降低.结论:建立了NTera2/CloneD1细胞向神经元分化的模型,NRSF在诱导后的NTera2/CloneD1细胞中表达量显著下调,提示NTera2/CloneD1细胞在诱导过程中可能通过下调NRSF,使受到NRSF负性调控的神经元特异性蛋白启动表达并上调,进而实现NTera2/CloneD1细胞向神经元的定向分化.%Objective: To establish a model of neuronal differentiation from NTera2/CloneDl human embryonal carcinoma cell line, and to analyze the expression of neuron-restrictive silencer factor (NRSF) before and after induction of neuronal differentiation. Methods: NTera2/CloneDl cells were cultured in normal or in induction medium for 28 days. The morphological changes of NTera2/CloneD 1 cells after induction were observed under the microscope. Immunofluorescence staining method was used to analyze the expression of multipotent genes Nestin, Sox2 and typical neuronal markers

  2. Association between polymorphisms of the APOBEC3G gene and chronic hepatitis B viral infection and hepatitis B virus-related hepatocellular carcinoma

    Science.gov (United States)

    He, Xiu-Ting; Xu, Hong-Qin; Wang, Xiao-Mei; He, Xiu-Shu; Niu, Jun-Qi; Gao, Pu-Jun

    2017-01-01

    AIM To determine the relationship between five A3G gene single nucleotide polymorphisms and the incidence of hepatitis B virus (HBV) infection and hepatocellular carcinoma (HCC). METHODS This association study was designed as a retrospective study, including 657 patients with chronic HBV infection (CHB) and 299 healthy controls. All subjects were ethnic Han Chinese. Chronic HBV-infected patients recruited between 2012 and 2015 at The First Hospital of Jilin University (Changchun) were further classified into HBV-related HCC patients (n = 287) and non-HCC patients (n = 370). Frequency matching by age and sex was performed for each group. Human genomic DNA was extracted from whole blood. Gene polymorphisms were identified using a mass spectroscopic method. RESULTS There were no significant differences between the genotype and allele frequencies of the rs7291971, rs5757465 and rs5757463 A3G gene polymorphisms, and risk of CHB and HBV-related HCC. The AG genotype and G allele for rs8177832 were significantly related to a decreased risk of CHB (OR = 0.67, 95%CI: 0.47-0.96; OR = 0.69, 95%CI: 0.50-0.95, respectively) and HCC (OR = 0.53, 95%CI: 0.34-0.84; OR = 0.58, 95%CI: 0.39-0.87, respectively). A significant relationship was found between rs2011861 computed tomography, TT genotypes and increased risk of HCC (OR = 1.69, 95%CI: 1.02-2.80; OR = 1.82, 95%CI: 1.08-3.06, respectively). Haplotype analyses showed three protective and four risk haplotypes for HCC. Also, one protective haplotype was found against CHB. CONCLUSION This study indicates that the A3G rs8177832 polymorphism is associated with a decreased risk of CHB infection and HCC, while the rs2011861 polymorphism is associated with an increased risk of HCC. PMID:28127197

  3. A FORTRAN Program for Correcting Correlation Coefficients for Restriction in Range for Explicit or Implicit Restriction.

    Science.gov (United States)

    Lewis, Mary A.; Boone, James O.

    1979-01-01

    Restriction in range is a measurement problem frequently encountered in research studies that utilize correlation coefficients. A FORTRAN program is described that can compute the estimated unrestricted correlation coefficient in either the explicit or implicit case. The user selects the appropriate formula to be employed from five that are…

  4. Human HERC5 restricts an early stage of HIV-1 assembly by a mechanism correlating with the ISGylation of Gag

    Directory of Open Access Journals (Sweden)

    Woods Matthew W

    2011-11-01

    Full Text Available Abstract Background The identification and characterization of several interferon (IFN-induced cellular HIV-1 restriction factors, defined as host cellular proteins or factors that restrict or inhibit the HIV-1 life cycle, have provided insight into the IFN response towards HIV-1 infection and identified new therapeutic targets for HIV-1 infection. To further characterize the mechanism underlying restriction of the late stages of HIV-1 replication, we assessed the ability of IFNbeta-induced genes to restrict HIV-1 Gag particle production and have identified a potentially novel host factor called HECT domain and RCC1-like domain-containing protein 5 (HERC5 that blocks a unique late stage of the HIV-1 life cycle. Results HERC5 inhibited the replication of HIV-1 over multiple rounds of infection and was found to target a late stage of HIV-1 particle production. The E3 ligase activity of HERC5 was required for blocking HIV-1 Gag particle production and correlated with the post-translational modification of Gag with ISG15. HERC5 interacted with HIV-1 Gag and did not alter trafficking of HIV-1 Gag to the plasma membrane. Electron microscopy revealed that the assembly of HIV-1 Gag particles was arrested at the plasma membrane, at an early stage of assembly. The mechanism of HERC5-induced restriction of HIV-1 particle production is distinct from the mechanism underlying HIV-1 restriction by the expression of ISG15 alone, which acts at a later step in particle release. Moreover, HERC5 restricted murine leukemia virus (MLV Gag particle production, showing that HERC5 is effective in restricting Gag particle production of an evolutionarily divergent retrovirus. Conclusions HERC5 represents a potential new host factor that blocks an early stage of retroviral Gag particle assembly. With no apparent HIV-1 protein that directly counteracts it, HERC5 may represent a new candidate for HIV/AIDS therapy.

  5. Effect of a standardised dietary restriction protocol on multiple laboratory strains of Drosophila melanogaster.

    Directory of Open Access Journals (Sweden)

    Richard C Grandison

    Full Text Available BACKGROUND: Outcomes of lifespan studies in model organisms are particularly susceptible to variations in technical procedures. This is especially true of dietary restriction, which is implemented in many different ways among laboratories. PRINCIPAL FINDINGS: In this study, we have examined the effect of laboratory stock maintenance, genotype differences and microbial infection on the ability of dietary restriction (DR to extend life in the fruit fly Drosophila melanogaster. None of these factors block the DR effect. CONCLUSIONS: These data lend support to the idea that nutrient restriction genuinely extends lifespan in flies, and that any mechanistic discoveries made with this model are of potential relevance to the determinants of lifespan in other organisms.

  6. Comparative effects of energy restriction and resveratrol intake on glycemic control improvement.

    Science.gov (United States)

    Milton-Laskibar, I; Aguirre, L; Macarulla, M T; Etxeberria, U; Milagro, F I; Martínez, J A; Contreras, J; Portillo, M P

    2017-02-20

    Resveratrol (RSV) has been proposed as an energy restriction mimetic. This study aimed to compare the effects of RSV and energy restriction on insulin resistance induced by an obesogenic diet. Any additive effect of both treatments was also analyzed. Rats were fed a high-fat high-sucrose diet for 6 weeks. They were then distributed in four experimental groups which were either fed a standard control diet (C), or treated with RSV (30 mg/kg/d), or submitted to energy restriction (R, 15%), or treated with RSV and submitted to energy restriction (RR). A glucose tolerance test was performed, and serum glucose, insulin, fructosamine, adiponectin, and leptin concentrations determined. Muscle triacylglycerol content and protein expression of insulin receptor (IRβ), protein kinase B (Akt), Akt substrate of 160 kDa (AS160) and glucose transporter 4 (GLUT-4) were measured. In RSV rats, fructosamine concentrations were reduced, HOMA-IR remained unchanged, but glucose tolerance was improved, without changes in phosphorylation of IRβ, Akt, and AS160 or in GLUT-4 protein expression. Rats under energy restriction showed an improvement in all the markers related to glycemic control, as well as increased phosphorylation of AS160 and protein expression of GLUT-4. In rats from RR group the results were similar to R group, with the exception of IRβ and Akt phosphorylation, which were increased. In conclusion, mild energy restriction is more efficient than intake of RSV within a standard balanced diet, and acts by means of a different mechanism from that of RSV. No additive effects between RSV and energy restriction were observed. © 2016 BioFactors, 2016.

  7. Formation reconfiguration in restricted three body problem

    Institute of Scientific and Technical Information of China (English)

    Shengping Gong; Junfeng Li; Hexi Baoyin; Yunfeng Gao

    2007-01-01

    Reconfiguration of formation flying around a halo orbit of the Sun-Earth restricted three body system is investigated with impulse maneuvers. For a short time reconfiguration, the two-impulse maneuver is investigated with both analytical and numerical methods and the BeginningEnding (BE) method is proven to be an energy-optimal one of all two-impulse (TI) reconfigurations, and the energy consumption of BE is independent of the position of the chief spacecraft, and decreases with the reconfiguration time.Then, genetic algorithm is adopted to optimize the energy consumption. The results show that the optimal energy increases with radius difference between the initial and final orbits, and decreases with the reconfiguration time.

  8. Constrictive Pericarditis Versus Restrictive Cardiomyopathy?

    Science.gov (United States)

    Garcia, Mario J

    2016-05-01

    About one-half of the patients with congestive heart failure have preserved left ventricular ejection fraction (HFpEF). Although the etiology of HFpEF is most commonly related to long-standing hypertension and atherosclerosis, a significant number of suspected HFpEF patients have a restrictive cardiomyopathy or chronic pericardial disease. Recognizing these syndromes is important because early diagnosis may lead to instituting specific therapy that may prolong survival, improve quality of life, and/or recognize and treat an underlying systemic disorder. Advances in diagnostic imaging, biomarkers, and genetic testing today allow identification of the specific etiology in most cases. Novel pharmacological, immunologic, and surgical therapies are leading to improved quality of life and survival.

  9. Classification of Sets using Restricted Boltzmann Machines

    CERN Document Server

    Louradour, Jérôme

    2011-01-01

    We consider the problem of classification when inputs correspond to sets of vectors. This setting occurs in many problems such as the classification of pieces of mail containing several pages, of web sites with several sections or of images that have been pre-segmented into smaller regions. We propose generalizations of the restricted Boltzmann machine (RBM) that are appropriate in this context and explore how to incorporate different assumptions about the relationship between the input sets and the target class within the RBM. In experiments on standard multiple-instance learning datasets, we demonstrate the competitiveness of approaches based on RBMs and apply the proposed variants to the problem of incoming mail classification.

  10. Restriction Enzymes in Microbiology, Biotechnology and Biochemistry

    Directory of Open Access Journals (Sweden)

    Geoffrey G. Wilson

    2012-12-01

    Full Text Available Since their discovery in the nineteen-seventies, a collection of simple enzymes termed Type II restriction endonucleases, made by microbes to ward off viral infections, have transformed molecular biology, spawned the multi-billion dollar Biotechnology industry, and yielded fundamental insights into the biochemistry of life, health and disease. In this article we describe how these enzymes were discovered, and we review their properties, organizations and genetics. We summarize current ideas about the mechanism underlying their remarkable ability to recognize and bind to specific base pair sequences in DNA, and we discuss why these ideas might not be correct. We conclude by proposing an alternative explanation for sequence-recognition that resolves certain inconsistencies and provides, in our view, a more satisfactory account of the mechanism.

  11. Training Restricted Boltzmann Machines on Word Observations

    CERN Document Server

    Dahl, George E; Larochelle, Hugo

    2012-01-01

    The restricted Boltzmann machine (RBM) is a flexible tool for modeling complex data, however there have been significant computational difficulties in using RBMs to model high-dimensional multinomial observations. In natural language processing applications, words are naturally modeled by K-ary discrete distributions, where K is determined by the vocabulary size and can easily be in the hundred thousands. The conventional approach to training RBMs on word observations is limited because it requires sampling the states of K-way softmax visible units during block Gibbs updates, an operation that takes time linear in K. In this work, we address this issue by employing a more general class of Markov chain Monte Carlo operators on the visible units, yielding updates with computational complexity independent of K. We demonstrate the success of our approach by training RBMs on hundreds of millions of word n-grams using larger vocabularies than previously feasible with RBMs and using the learned features to improve p...

  12. Mining for Restriction Endonucleases in Nicaragua

    Directory of Open Access Journals (Sweden)

    Suyén S. Espinoza-Miranda

    2012-12-01

    Full Text Available The Molecular Biology Center at the University of Central America in Nicaragua (CBM-UCA was founded in 1999 to strengthen biotechnology research capacity and education in Nicaragua and the Central American region. One of the first projects launched by the CBM-UCA was bio-prospecting for key industrial enzymes. This ongoing study seeks to discover and characterize restriction enzymes (RE in bacteria, and to create a database of microorganisms isolated and identified by 16S rDNA sequencing methodology. In this paper we highlight the importance of studying the extreme environmental conditions for building knowledge of Nicaraguan biodiversity through modern molecular biology techniques such as metagenomics. The isolation of prototype enzymes such as EcoRV and ClaI is presented as an update and extension of previously undertaken work.

  13. Epitaxial growth by monolayer restricted galvanic displacement

    Directory of Open Access Journals (Sweden)

    Vasilić Rastko

    2012-01-01

    Full Text Available The development of a new method for epitaxial growth of metals in solution by galvanic displacement of layers pre-deposited by underpotential deposition (UPD was discussed and experimentally illustrated throughout the lecture. Cyclic voltammetry (CV and scanning tunneling microscopy (STM are employed to carry out and monitor a “quasi-perfect”, two-dimensional growth of Ag on Au(111, Cu on Ag(111, and Cu on Au(111 by repetitive galvanic displacement of underpotentially deposited monolayers. A comparative study emphasizes the displacement stoichiometry as an efficient tool for thickness control during the deposition process and as a key parameter that affects the deposit morphology. The excellent quality of layers deposited by monolayer-restricted galvanic displacement is manifested by a steady UPD voltammetry and ascertained by a flat and uniform surface morphology maintained during the entire growth process.

  14. Trophoblast differentiation, fetal growth restriction and preeclampsia.

    Science.gov (United States)

    Huppertz, Berthold

    2011-01-01

    The number of hypotheses trying to decipher the etiologies of preeclampsia and fetal growth restriction (FGR) is still increasing. However, for preeclampsia the actual knowledge we have is that the placenta is a prerequisite for the development of the syndrome. The recent years have seen a shift in understanding of the causes of preeclampsia from mostly focusing on the extravillous trophoblast towards the dysregulation of villous trophoblast development and maintenance. It seems as if a failure of the villous syncytiotrophoblast differentiation results in abnormal release of non-apoptotic fragments into maternal blood. In preeclampsia such necrotic or aponecrotic fragments can be found in maternal blood systemically and seem to be causative in the development of the inflammatory response of the mother. In cases with fetal growth restriction (FGR) extravillous trophoblast fails to adequately transform uterine spiral arteries. However, in FGR cases abnormal development of villous cytotrophoblast may have an impact on fetal nutrition without the induction of an inflammatory response of the mother. It is still unclear why the villous trophoblast fails to achieve an adequate turnover both in preeclampsia and in FGR. However, the detection of new biomarkers for preeclampsia such as placental protein 13 (PP13) has helped in clarifying the issue of when the syndrome starts to develop. PP13 levels in maternal serum are significantly altered already at six to seven weeks of gestation in women subsequently developing preeclampsia. Thus, there needs to be a very early alteration of villous development in such placentas. Herein the changes in villous trophoblast in preeclampsia and FGR are compared and differences between both scenarios are presented.

  15. AGORA: Assembly Guided by Optical Restriction Alignment

    Directory of Open Access Journals (Sweden)

    Lin Henry C

    2012-08-01

    Full Text Available Abstract Background Genome assembly is difficult due to repeated sequences within the genome, which create ambiguities and cause the final assembly to be broken up into many separate sequences (contigs. Long range linking information, such as mate-pairs or mapping data, is necessary to help assembly software resolve repeats, thereby leading to a more complete reconstruction of genomes. Prior work has used optical maps for validating assemblies and scaffolding contigs, after an initial assembly has been produced. However, optical maps have not previously been used within the genome assembly process. Here, we use optical map information within the popular de Bruijn graph assembly paradigm to eliminate paths in the de Bruijn graph which are not consistent with the optical map and help determine the correct reconstruction of the genome. Results We developed a new algorithm called AGORA: Assembly Guided by Optical Restriction Alignment. AGORA is the first algorithm to use optical map information directly within the de Bruijn graph framework to help produce an accurate assembly of a genome that is consistent with the optical map information provided. Our simulations on bacterial genomes show that AGORA is effective at producing assemblies closely matching the reference sequences. Additionally, we show that noise in the optical map can have a strong impact on the final assembly quality for some complex genomes, and we also measure how various characteristics of the starting de Bruijn graph may impact the quality of the final assembly. Lastly, we show that a proper choice of restriction enzyme for the optical map may substantially improve the quality of the final assembly. Conclusions Our work shows that optical maps can be used effectively to assemble genomes within the de Bruijn graph assembly framework. Our experiments also provide insights into the characteristics of the mapping data that most affect the performance of our algorithm, indicating the

  16. Nutrient intake and food restriction in children with atopic dermatitis.

    Science.gov (United States)

    Lim, Hyunjin; Song, Kyunghee; Kim, Ran; Sim, Jiyeon; Park, Eunah; Ahn, Kangmo; Kim, Jihyun; Han, Youngshin

    2013-01-01

    This study was performed to investigate the status of food restriction and the list of restricted foods in children with moderate to severe atopic dermatitis (AD), and to find out the effect of food restriction on the changes in nutrient intake and the severity of the disease. Sixty two patient children aged 12 months to 13 years presenting AD with a SCORing of Atopic Dermatitis (SCORAD) index between 20 and 50 were enrolled. The presence of food limitation, and list of restricted foods were surveyed through the caretakers and the patients were divided into 3 groups by the number of restricted food: non-restricted group, one to three restricted group, and more than three restricted group. Dietary intake was assessed for 3 months using a food frequency questionnaire (FFQ). Half of the subjects restricted foods. The restriction was higher in the order of soda, food additives, walnut, peanut, and other nuts as a single food item; and shellfish and crustacean group, processed foods, nuts, milk & dairy products, and meats as a food group. More than three restricted group ingested more fruits and less fish and meats, resulting in high consumption of vitamin C (p = 0.027). No significant difference in the ratio of nutrient intake by the number of restricted foods was observed in other nutrients. Significant improvement of AD symptom was observed in non-restricted group (p = 0.036) and one to three restricted group (p = 0.003). It is necessary to provide proper nutrition information and systematic and continuous nutrition management for balanced nutrient intake and disease improvement in children with AD.

  17. Cofactor requirement of HpyAV restriction endonuclease.

    Directory of Open Access Journals (Sweden)

    Siu-Hong Chan

    Full Text Available BACKGROUND: Helicobacter pylori is the etiologic agent of common gastritis and a risk factor for gastric cancer. It is also one of the richest sources of Type II restriction-modification (R-M systems in microorganisms. PRINCIPAL FINDINGS: We have cloned, expressed and purified a new restriction endonuclease HpyAV from H. pylori strain 26695. We determined the HpyAV DNA recognition sequence and cleavage site as CCTTC 6/5. In addition, we found that HpyAV has a unique metal ion requirement: its cleavage activity is higher with transition metal ions than in Mg(++. The special metal ion requirement of HpyAV can be attributed to the presence of a HNH catalytic site similar to ColE9 nuclease instead of the canonical PD-X-D/EXK catalytic site found in many other REases. Site-directed mutagenesis was carried out to verify the catalytic residues of HpyAV. Mutation of the conserved metal-binding Asn311 and His320 to alanine eliminated cleavage activity. HpyAV variant H295A displayed approximately 1% of wt activity. CONCLUSIONS/SIGNIFICANCE: Some HNH-type endonucleases have unique metal ion cofactor requirement for optimal activities. Homology modeling and site-directed mutagenesis confirmed that HpyAV is a member of the HNH nuclease family. The identification of catalytic residues in HpyAV paved the way for further engineering of the metal binding site. A survey of sequenced microbial genomes uncovered 10 putative R-M systems that show high sequence similarity to the HpyAV system, suggesting lateral transfer of a prototypic HpyAV-like R-M system among these microorganisms.

  18. Restriction of bacteriophage plaque formation in Streptomyces spp.

    Science.gov (United States)

    Cox, K L; Baltz, R H

    1984-08-01

    Several Streptomyces species that produce restriction endonucleases were characterized for their ability to propagate 10 different broad host range bacteriophages. Each species displayed a different pattern of plaque formation. A restrictionless mutant of S. albus G allowed plaque formation by all 10 phages, whereas the wild-type strain showed plaques with only 2 phages. DNA isolated from three of the phages was analyzed for the presence of restriction sites for Streptomyces species-encoded enzymes, and a very strong correlation was established between the failure to form plaques on Streptomyces species that produced particular restriction enzymes and the presence of the corresponding restriction sites in the phage DNA. Also, the phages that lacked restriction sites in their DNA generally formed plaques on the corresponding restriction endonuclease-producing hosts at high efficiency. The DNAs from the three phages analyzed also generally contained either many or no restriction sites for the Streptomyces species-produced enzymes, suggesting a strong evolutionary trend to either eliminate all or tolerate many restriction sites. The data indicate that restriction plays a major role in host range determination for Streptomyces phages. Analysis of bacteriophage host ranges of many other uncharacterized Streptomyces hosts has identified four relatively nonrestricting hosts, at least two of which may be suitable hosts for gene cloning. The data also suggest that several restriction systems remain to be identified in the genus Streptomyces.

  19. Restrictive influence of SAMHD1 on Hepatitis B Virus life cycle

    Science.gov (United States)

    Sommer, Andreas F. R.; Rivière, Lise; Qu, Bingqian; Schott, Kerstin; Riess, Maximilian; Ni, Yi; Shepard, Caitlin; Schnellbächer, Esther; Finkernagel, Malin; Himmelsbach, Kiyoshi; Welzel, Karin; Kettern, Nadja; Donnerhak, Christian; Münk, Carsten; Flory, Egbert; Liese, Juliane; Kim, Baek; Urban, Stephan; König, Renate

    2016-01-01

    Deoxynucleotide triphosphates (dNTPs) are essential for efficient hepatitis B virus (HBV) replication. Here, we investigated the influence of the restriction factor SAMHD1, a dNTP hydrolase (dNTPase) and RNase, on HBV replication. We demonstrated that silencing of SAMHD1 in hepatic cells increased HBV replication, while overexpression had the opposite effect. SAMHD1 significantly affected the levels of extracellular viral DNA as well as intracellular reverse transcription products, without affecting HBV RNAs or cccDNA. SAMHD1 mutations that interfere with the dNTPase activity (D137N) or in the catalytic center of the histidine-aspartate (HD) domain (D311A), and a phospho-mimetic mutation (T592E), abrogated the inhibitory activity. In contrast, a mutation diminishing the potential RNase but not dNTPase activity (Q548A) and a mutation disabling phosphorylation (T592A) did not affect antiviral activity. Moreover, HBV restriction by SAMHD1 was rescued by addition of deoxynucleosides. Although HBV infection did not directly affect protein level or phosphorylation of SAMHD1, the virus upregulated intracellular dATPs. Interestingly, SAMHD1 was dephosphorylated, thus in a potentially antiviral-active state, in primary human hepatocytes. Furthermore, SAMHD1 was upregulated by type I and II interferons in hepatic cells. These results suggest that SAMHD1 is a relevant restriction factor for HBV and restricts reverse transcription through its dNTPase activity. PMID:27229711

  20. Reshuffling and Relocating: The Gendered and Income-Related Differential Effects of Restricting Smoking Locations

    Directory of Open Access Journals (Sweden)

    Natalie Hemsing

    2012-01-01

    Full Text Available This study investigates secondhand smoke (SHS exposure and management in the context of smoking location restrictions, for nonsmokers, former, and current smokers. A purposive sample of 47 low income and non-low-income men and women of varied smoking statuses was recruited to participate in a telephone interview or a focus group. Amidst general approval of increased restrictions there were gendered patterns of SHS exposure and management, and effects of SHS policies that reflect power, control, and social roles that need to be considered as policies are developed, implemented and monitored. The experience of smoking restrictions and the management of SHS is influenced by the social context (relationship with a partner, family member, or stranger, the space of exposure (public or private, worksite, the social location of individuals involved (gender, income, and differential tolerance to SHS. This confluence of factors creates differing unintended and unexpected consequences to the social and physical situations of male and female smokers, nonsmokers, and former smokers. These factors deserve further study, in the interests of informing the development of future interventions and policies restricting SHS.

  1. Estimation of average causal effect using the restricted mean residual lifetime as effect measure

    DEFF Research Database (Denmark)

    Mansourvar, Zahra; Martinussen, Torben

    2016-01-01

    with respect to their survival times. In observational studies where the factor of interest is not randomized, covariate adjustment is needed to take into account imbalances in confounding factors. In this article, we develop an estimator for the average causal treatment difference using the restricted mean...... residual lifetime as target parameter. We account for confounding factors using the Aalen additive hazards model. Large sample property of the proposed estimator is established and simulation studies are conducted in order to assess small sample performance of the resulting estimator. The method is also...

  2. Detection of possible restriction sites for type II restriction enzymes in DNA sequences.

    Science.gov (United States)

    Gagniuc, P; Cimponeriu, D; Ionescu-Tîrgovişte, C; Mihai, Andrada; Stavarachi, Monica; Mihai, T; Gavrilă, L

    2011-01-01

    In order to make a step forward in the knowledge of the mechanism operating in complex polygenic disorders such as diabetes and obesity, this paper proposes a new algorithm (PRSD -possible restriction site detection) and its implementation in Applied Genetics software. This software can be used for in silico detection of potential (hidden) recognition sites for endonucleases and for nucleotide repeats identification. The recognition sites for endonucleases may result from hidden sequences through deletion or insertion of a specific number of nucleotides. Tests were conducted on DNA sequences downloaded from NCBI servers using specific recognition sites for common type II restriction enzymes introduced in the software database (n = 126). Each possible recognition site indicated by the PRSD algorithm implemented in Applied Genetics was checked and confirmed by NEBcutter V2.0 and Webcutter 2.0 software. In the sequence NG_008724.1 (which includes 63632 nucleotides) we found a high number of potential restriction sites for ECO R1 that may be produced by deletion (n = 43 sites) or insertion (n = 591 sites) of one nucleotide. The second module of Applied Genetics has been designed to find simple repeats sizes with a real future in understanding the role of SNPs (Single Nucleotide Polymorphisms) in the pathogenesis of the complex metabolic disorders. We have tested the presence of simple repetitive sequences in five DNA sequence. The software indicated exact position of each repeats detected in the tested sequences. Future development of Applied Genetics can provide an alternative for powerful tools used to search for restriction sites or repetitive sequences or to improve genotyping methods.

  3. Use of primer selection and restriction enzymes to assess bacterial community diversity in an agricultural soil used for potato production via terminal restriction fragment length polymorphism.

    Science.gov (United States)

    Fortuna, Ann-Marie; Marsh, Terence L; Honeycutt, C Wayne; Halteman, William A

    2011-08-01

    Terminal restriction fragment length polymorphism (T-RFLP) can be used to assess how land use management changes the dominant members of bacterial communities. We compared T-RFLP profiles obtained via amplification with forward primers (27, 63F) each coupled with the fluorescently labeled reverse primer (1392R) and multiple restriction enzymes to determine the best combination for interrogating soil bacterial populations in an agricultural soil used for potato production. Both primer pairs provide nearly universal recognition of a 1,400-bp sequence of the bacterial domain in the V(1)-V(3) region of the 16S ribosomal RNA (rRNA) gene relative to known sequences. Labeling the reverse primer allowed for direct comparison of each forward primer and the terminal restriction fragments' relative migration units obtained with each primer pair and restriction enzyme. Redundancy analysis (RDA) and nested multivariate analysis of variance (MANOVA) were used to assess the effects of primer pair and choice of restriction enzyme on the measured relative migration units. Our research indicates that the 63F-1392R amplimer pair provides a more complete description with respect to the bacterial communities present in this potato (Solanum tuberosum L.)-barley (Hordeum vulgare L.) rotation over seeded to crimson clover (Trifolium praense L.). Domain-specific 16S rRNA gene primers are rigorously tested to determine their ability to amplify across a target region of the gene. Yet, variability within or between T-RFLP profiles can result from factors independent of the primer pair. Therefore, researchers should use RDA and MANOVA analyses to evaluate the effects that additional laboratory and environmental variables have on bacterial diversity.

  4. A Canonical Correlation Analysis of AIDS Restriction Genes and Metabolic Pathways Identifies Purine Metabolism as a Key Cooperator

    Directory of Open Access Journals (Sweden)

    Hanhui Ye

    2016-01-01

    Full Text Available Human immunodeficiency virus causes a severe disease in humans, referred to as immune deficiency syndrome. Studies on the interaction between host genetic factors and the virus have revealed dozens of genes that impact diverse processes in the AIDS disease. To resolve more genetic factors related to AIDS, a canonical correlation analysis was used to determine the correlation between AIDS restriction and metabolic pathway gene expression. The results show that HIV-1 postentry cellular viral cofactors from AIDS restriction genes are coexpressed in human transcriptome microarray datasets. Further, the purine metabolism pathway comprises novel host factors that are coexpressed with AIDS restriction genes. Using a canonical correlation analysis for expression is a reliable approach to exploring the mechanism underlying AIDS.

  5. Mechanistic insights into type III restriction enzymes.

    Science.gov (United States)

    Raghavendra, Nidhanapati K; Bheemanaik, Shivakumara; Rao, Desirazu N

    2012-01-01

    Type III restriction-modification (R-M) enzymes need to interact with two separate unmethylated DNA sequences in indirectly repeated, head-to-head orientations for efficient cleavage to occur at a defined location next to only one of the two sites. However, cleavage of sites that are not in head-to-head orientation have been observed to occur under certain reaction conditions in vitro. ATP hydrolysis is required for the long-distance communication between the sites prior to cleavage. Type III R-M enzymes comprise two subunits, Res and Mod that form a homodimeric Mod2 and a heterotetrameric Res2Mod2 complex. The Mod subunit in M2 or R2M2 complex recognizes and methylates DNA while the Res subunit in R2M2 complex is responsible for ATP hydrolysis, DNA translocation and cleavage. A vast majority of biochemical studies on Type III R-M enzymes have been undertaken using two closely related enzymes, EcoP1I and EcoP15I. Divergent opinions about how the long-distance interaction between the recognition sites exist and at least three mechanistic models based on 1D- diffusion and/or 3D- DNA looping have been proposed.

  6. Maternal dietary restriction alters offspring's sleep homeostasis.

    Directory of Open Access Journals (Sweden)

    Noriyuki Shimizu

    Full Text Available Nutritional state in the gestation period influences fetal growth and development. We hypothesized that undernutrition during gestation would affect offspring sleep architecture and/or homeostasis. Pregnant female mice were assigned to either control (fed ad libitum; AD or 50% dietary restriction (DR groups from gestation day 12 to parturition. After parturition, dams were fed AD chow. After weaning, the pups were also fed AD into adulthood. At adulthood (aged 8-9 weeks, we carried out sleep recordings. Although offspring mice displayed a significantly reduced body weight at birth, their weights recovered three days after birth. Enhancement of electroencephalogram (EEG slow wave activity (SWA during non-rapid eye movement (NREM sleep was observed in the DR mice over a 24-hour period without changing the diurnal pattern or amounts of wake, NREM, or rapid eye movement (REM sleep. In addition, DR mice also displayed an enhancement of EEG-SWA rebound after a 6-hour sleep deprivation and a higher threshold for waking in the face of external stimuli. DR adult offspring mice exhibited small but significant increases in the expression of hypothalamic peroxisome proliferator-activated receptor α (Pparα and brain-specific carnitine palmitoyltransferase 1 (Cpt1c mRNA, two genes involved in lipid metabolism. Undernutrition during pregnancy may influence sleep homeostasis, with offspring exhibiting greater sleep pressure.

  7. Intrauterine Growth Restriction: Antenatal and Postnatal Aspects

    Science.gov (United States)

    Sharma, Deepak; Shastri, Sweta; Sharma, Pradeep

    2016-01-01

    Intrauterine growth restriction (IUGR), a condition that occurs due to various reasons, is an important cause of fetal and neonatal morbidity and mortality. It has been defined as a rate of fetal growth that is less than normal in light of the growth potential of that specific infant. Usually, IUGR and small for gestational age (SGA) are used interchangeably in literature, even though there exist minute differences between them. SGA has been defined as having birth weight less than two standard deviations below the mean or less than the 10th percentile of a population-specific birth weight for specific gestational age. These infants have many acute neonatal problems that include perinatal asphyxia, hypothermia, hypoglycemia, and polycythemia. The likely long-term complications that are prone to develop when IUGR infants grow up includes growth retardation, major and subtle neurodevelopmental handicaps, and developmental origin of health and disease. In this review, we have covered various antenatal and postnatal aspects of IUGR. PMID:27441006

  8. Earth system multi-body restriction dynamics model research

    Institute of Scientific and Technical Information of China (English)

    ZHANG; Qingxian; BI; Siwen; GONG; Huili

    2006-01-01

    Research provides a theoretical basis for an Earth system multi-body mechanics model and its dynamics, including the Earth system multi-body restriction function and its power, Earth system multi-body restriction under decreasing generalized velocity and decreasing partial palstance, the Earth system multi-body decreasing generalized force, a moving mechanics function, and the Earth system multi-body restriction's wattful and wattless forces.

  9. Maternal Nutrient Restriction Predisposes Ventricular Remodeling in Adult Sheep Offspring

    OpenAIRE

    Ge, Wei; Hu, Nan; George, Lindsey A; Ford, Stephen P.; Peter W Nathanielsz; Wang, Xiaoming; Ren, Jun

    2013-01-01

    Maternal nutrient restriction during pregnancy is associated with the development of a “thrifty phenotype” in offspring, conferring increased prevalence of metabolic diseases in adulthood. To explore the possible mechanisms behind heart diseases in adulthood following maternal nutrient restriction, dams were fed a nutrient restricted (NR: 50%) or control (100%) diet from 28 to 78 d of gestation. Both groups were then fed 100% of requirements to lambing. At 6 yrs of age, female offspring of NR...

  10. Type I restriction endonucleases are true catalytic enzymes.

    Science.gov (United States)

    Bianco, Piero R; Xu, Cuiling; Chi, Min

    2009-06-01

    Type I restriction endonucleases are intriguing, multifunctional complexes that restrict DNA randomly, at sites distant from the target sequence. Restriction at distant sites is facilitated by ATP hydrolysis-dependent, translocation of double-stranded DNA towards the stationary enzyme bound at the recognition sequence. Following restriction, the enzymes are thought to remain associated with the DNA at the target site, hydrolyzing copious amounts of ATP. As a result, for the past 35 years type I restriction endonucleases could only be loosely classified as enzymes since they functioned stoichiometrically relative to DNA. To further understand enzyme mechanism, a detailed analysis of DNA cleavage by the EcoR124I holoenzyme was done. We demonstrate for the first time that type I restriction endonucleases are not stoichiometric but are instead catalytic with respect to DNA. Further, the mechanism involves formation of a dimer of holoenzymes, with each monomer bound to a target sequence and, following cleavage, each dissociates in an intact form to bind and restrict subsequent DNA molecules. Therefore, type I restriction endonucleases, like their type II counterparts, are true enzymes. The conclusion that type I restriction enzymes are catalytic relative to DNA has important implications for the in vivo function of these previously enigmatic enzymes.

  11. Perceived Benefits of Fisheries Management Restrictions in Madagascar

    Directory of Open Access Journals (Sweden)

    Tim R. McClanahan

    2014-03-01

    Full Text Available Perceptions of the benefits of fisheries management restrictions were evaluated in coastal Madagascar to identify restrictions that are likely to be self- and community enforced. The survey focused on 24 Malagasy fishing villages adjacent to coral reefs. Resource users' perceptions of the benefits of restrictions were generally high and widespread, but some less positive perceptions were found in three villages located near marine protected areas. Perceptions of the benefits of gear restrictions had widespread support; closed areas, seasons, and minimum sizes of fish were less common; and restrictions on species were supported infrequently. We therefore advocate a management implementation approach that uses these scales of perceived benefits and prioritizes support for the most widely accepted restrictions most broadly, with the less accepted restrictions matched to specific supportive locations. At the village level, socioeconomic and wealth variables were not clearly associated with perceived benefits, which we suggest results from a stronger influence of village history than socioeconomic conditions. At the individual fisher level, however, there was evidence that experienced people involved in decision-making, having livelihood alternatives, and having permanent housing had more opinions and frequently were more supportive of management restrictions. Incorporating this information into forums and management plans is expected to increase the rate of adoption and compliance with needed fisheries restrictions.

  12. Dietary restriction: could it be considered as speed bump on tumor progression road?

    Science.gov (United States)

    Cangemi, Antonina; Fanale, Daniele; Rinaldi, Gaetana; Bazan, Viviana; Galvano, Antonio; Perez, Alessandro; Barraco, Nadia; Massihnia, Daniela; Castiglia, Marta; Vieni, Salvatore; Bronte, Giuseppe; Mirisola, Mario; Russo, Antonio

    2016-06-01

    Dietary restrictions, including fasting (or long-term starvation), calorie restriction (CR), and short-term starvation (STS), are considered a strong rationale that may protect against various diseases, including age-related diseases and cancer. Among dietary approaches, STS, in which food is not consumed during designed fasting periods but is typically not restricted during designated feeding periods, seems to be more suitable, because other dietary regimens involving prolonged fasting periods could worsen the health conditions of cancer patients, being they already naturally prone to weight loss. Until now, the limited amount of available data does not point to a single gene, pathway, or molecular mechanism underlying the benefits to the different dietary approaches. It is well known that the healthy effect is mediated in part by the reduction of nutrient-related pathways. The calorie restriction and starvation (long- and short-term) also suppress the inflammatory response reducing the expression, for example, of IL-10 and TNF-α, mitigating pro-inflammatory gene expression and increasing anti-inflammatory gene expression. The dietary restriction may regulate both genes involved in cellular proliferation and factors associated to apoptosis in normal and cancer cells. Finally, dietary restriction is an important tool that may influence the response to chemotherapy in preclinical models. However, further data are needed to correlate dietary approaches with chemotherapeutic treatments in human models. The aim of this review is to discuss the effects of various dietary approaches on the cancer progression and therapy response, mainly in preclinical models, describing some signaling pathways involved in these processes.

  13. Determinants of participation restriction among community dwelling stroke survivors: A path analysis

    Directory of Open Access Journals (Sweden)

    Chang Anne M

    2009-09-01

    Full Text Available Abstract Background Apart from promoting physical recovery and assisting in activities of daily living, a major challenge in stroke rehabilitation is to minimize psychosocial morbidity and to promote the reintegration of stroke survivors into their family and community. The identification of key factors influencing long-term outcome are essential in developing more effective rehabilitation measures for reducing stroke-related morbidity. The aim of this study was to test a theoretical model of predictors of participation restriction which included the direct and indirect effects between psychosocial outcomes, physical outcome, and socio-demographic variables at 12 months after stroke. Methods Data were collected from 188 stroke survivors at 12 months following their discharge from one of the two rehabilitation hospitals in Hong Kong. The settings included patients' homes and residential care facilities. Path analysis was used to test a hypothesized model of participation restriction at 12 months. Results The path coefficients show functional ability having the largest direct effect on participation restriction (β = 0.51. The results also show that more depressive symptoms (β = -0.27, low state self-esteem (β = 0.20, female gender (β = 0.13, older age (β = -0.11 and living in a residential care facility (β = -0.12 have a direct effect on participation restriction. The explanatory variables accounted for 71% of the variance in explaining participation restriction at 12 months. Conclusion Identification of stroke survivors at risk of high levels of participation restriction, depressive symptoms and low self-esteem will assist health professionals to devise appropriate rehabilitation interventions that target improving both physical and psychosocial functioning.

  14. Hypothalamic neuropeptide expression following chronic food restriction in sedentary and wheel-running rats.

    Science.gov (United States)

    de Rijke, C E; Hillebrand, J J G; Verhagen, L A W; Roeling, T A P; Adan, R A H

    2005-10-01

    When rats are given access to a running-wheel in combination with food restriction, they will become hyperactive and decrease their food intake, a paradoxical phenomenon known as activity-based anorexia (ABA). Little is known about the regulation of the hypothalamic neuropeptides that are involved in the regulation of food intake and energy balance during the development of ABA. Therefore, rats were killed during the development of ABA, before they entered a state of severe starvation. Neuropeptide mRNA expression levels were analysed using quantitative real-time PCR on punches of separate hypothalamic nuclei. As is expected in a state of negative energy balance, expression levels of agouti-related protein (AgRP) and neuropeptide Y (NPY) were increased 5-fold in the arcuate nucleus (ARC) of food-restricted running ABA rats vs 2-fold in sedentary food-restricted controls. The co-regulated expression of AgRP and NPY strongly correlated with relative body weight and white adipose tissue mass. Arcuate expression of pro-opiomelanocortin (POMC) and cocaine- and amphetamine-regulated transcript (CART) was reduced 2-fold in the ABA group. In second-order neurons of the lateral hypothalamic area (LHA), melanin-concentrating hormone (MCH) mRNA expression was upregulated 2-fold in food-restricted running rats, but not in food-restricted sedentary controls. Prepro-orexin, CART and corticotropin-releasing hormone expression levels in the LHA and the paraventricular nucleus (PVN) were unchanged in both food-restricted groups. From this study it was concluded that during the development of ABA, neuropeptides in first-order neurons in the ARC and MCH in the LHA are regulated in an adequate response to negative energy balance, whereas expression levels of the other studied neuropeptides in secondary neurons of the LHA and PVN are unchanged and are probably regulated by factors other than energy status alone.

  15. Comparison of a Restricted and Unrestricted Vegan Diet Plan with a Restricted Omnivorous Diet Plan on Health-Specific Measures

    OpenAIRE

    Richard J. Bloomer; Gunnels, Trint A; Schriefer, JohnHenry M.

    2015-01-01

    Background: We have previously noted beneficial health outcomes when individuals follow a dietary restriction plan in accordance with the Daniel Fast (DF). This is true whether individuals eliminate all animal products or include small amounts of meat and dairy in their plan. The present study sought to compare anthropometric and biochemical measures of health in individuals following a traditional DF (i.e., restricted vegan) or modified DF (i.e., restricted omnivorous; inclusive of ad libitu...

  16. Restrictions of physical activity participation in older adults with disability: employing keyword network analysis

    OpenAIRE

    Koo, Kyo-Man; Kim, Chun-Jong; Park, Chae-Hee; Byeun, Jung-Kyun; Seo, Geon-Woo

    2016-01-01

    Older adults with disability might have been increasing due to the rapid aging of society. Many studies showed that physical activity is an essential part for improving quality of life in later lives. Regular physical activity is an efficient means that has roles of primary prevention and secondary prevention. However, there were few studies regarding older adults with disability and physical activity participation. The purpose of this current study was to investigate restriction factors to r...

  17. Identification of Loci Controlling Restriction of Parasite Growth in Experimental Taenia crassiceps Cysticercosis

    OpenAIRE

    Ruben Ramirez-Aquino; Irena Radovanovic; Anny Fortin; Edda Sciutto-Conde; Gladis Fragoso-González; Philippe Gros; Irma Aguilar-Delfin

    2011-01-01

    Human neurocysticercosis (NC) caused by Taenia solium is a parasitic disease of the central nervous system that is endemic in many developing countries. In this study, a genetic approach using the murine intraperitoneal cysticercosis caused by the related cestode Taenia crassiceps was employed to identify host factors that regulate the establishment and proliferation of the parasite. A/J mice are permissive to T. crassiceps infection while C57BL/6J mice (B6) are comparatively restrictive, wit...

  18. Does SIRT-1 Mediate Calorie Restriction and Prolong Life? – A Mini Review

    Directory of Open Access Journals (Sweden)

    Kordala Anna

    2014-09-01

    Full Text Available Calorie restriction is the only intervention proved to prolong both average and maximum lifespan in yeast, worms, fish, rodents and possibly primates. Not only does the regimen prolong life, but it also reduces the incident of numerous age-related diseases like diabetes, atherosclerosis or cancer and slows down ageing. Mechanisms by which that is thought to occur have not yet been elucidated, but they probably involve reactive oxygen species signaling, insulin growth factor and transcriptional factors. Here, special emphasis is given to SIRT1 - silent information regulator. There is sound evidence showing that SIRT1 is a key player in mediating physiological response to calorie restriction and that its overexpression is correlated with extended lifespan. The possible mechanism leading to its elevated levels is high NAD/NADH ratio, observed in Sir2 in yeast. SIRT1 increases glucose production, enhances fat mobilization, stimulates angiogenesis, prevents neuronal degeneration and rises insulin sensitivity. Therefore, it seems to be a very beneficial factor activated by such a simple intervention that is calorie restriction.

  19. Tetherin restricts productive HIV-1 cell-to-cell transmission.

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    Nicoletta Casartelli

    Full Text Available The IFN-inducible antiviral protein tetherin (or BST-2/CD317/HM1.24 impairs release of mature HIV-1 particles from infected cells. HIV-1 Vpu antagonizes the effect of tetherin. The fate of virions trapped at the cell surface remains poorly understood. Here, we asked whether tetherin impairs HIV cell-to-cell transmission, a major means of viral spread. Tetherin-positive or -negative cells, infected with wild-type or DeltaVpu HIV, were used as donor cells and cocultivated with target lymphocytes. We show that tetherin inhibits productive cell-to-cell transmission of DeltaVpu to targets and impairs that of WT HIV. Tetherin accumulates with Gag at the contact zone between infected and target cells, but does not prevent the formation of virological synapses. In the presence of tetherin, viruses are then mostly transferred to targets as abnormally large patches. These viral aggregates do not efficiently promote infection after transfer, because they accumulate at the surface of target cells and are impaired in their fusion capacities. Tetherin, by imprinting virions in donor cells, is the first example of a surface restriction factor limiting viral cell-to-cell spread.

  20. Alteration of the Specificity of PstⅠRestriction Endonuclease

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The influence of factors on the substrate-specificity of Pst Ⅰ restriction endonuclease has been studied with the method of electrophoresis. The results show that, the specificity of Pst Ⅰ almost can not be influenced by the single alteration of the concentration of Tris*HCl, Mg2+ or Na+ in the reaction system, but it can be altered by the reduction of any two of them. The specificity can not be altered by the single alteration of pH or the replacement of Mg2+ with Mn2+. The addition of glycerol or dimethylsulphoxide (DMSO) to the reaction system results in the relaxation of the substrate-specificity of Pst Ⅰ , but dimethylmethylformide, glycol and ethyl alcohol can not bring about the alteration of Pst Ⅰ specificity. Through the method of cloning and sequencing, the nucleotides of No.1 and 6 in the recognition sequence of Pst Ⅰ have changed (1C→A or 6G→T). Used with the enzyme analysis of an artificially synthetic DNA segment containing a special sequence, the nucleotides of No.1 and 6 have both changed (1C→A and 6G→T). The recognition sequence of Pst Ⅰ is speculated to be changed from CTGCA↓G to TGCA↓.


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