Phosphatidylserine receptors: Enhancers of enveloped virus entry and infection

AbstractA variety of both RNA and DNA viruses envelop their capsids in a lipid bilayer. One of the more recently appreciated benefits this envelope is incorporation of phosphatidylserine (PtdSer). Surface exposure of PtdSer disguises viruses as apoptotic bodies; tricking cells into engulfing virions. This mechanism is termed apoptotic mimicry. Several PtdSer receptors have been identified to enhance virus entry and we have termed this group of proteins PtdSer-mediated virus entry enhancing receptors or PVEERs. These receptors enhance entry of a range of enveloped viruses. Internalization of virions by PVEERs provides a broad mechanism of entry with little investment by the virus itself. PVEERs may allow some viruses to attach to cells, thereby making viral glycoprotein/cellular receptor interactions more probable. Alternatively, other viruses may rely entirely on PVEERs for internalization into endosomes. This review provides an overview of PtdSer receptors that serve as PVEERs and the biology behind virion/PVEER interaction

Cell Specificity of the Transcription-Factor Repertoire Used by a Lentivirus: Motifs Important for Expression of Equine Infectious Anemia Virus in Nonmonocytic Cells

AbstractThe equine infectious anemia virus (EIAV) long-terminal repeat (LTR) has been identified as highly variable, both in infected horses and in cell culture. This nucleotide hypervariation is localized to the LTR enhancer region. The EIAV LTR has been implicated in controlling both the cell tropism and virulence of the virus and it is postulated that the enhancer-region hypervariation may be responsible for the LTR effects. Our previous studies have demonstrated that the presence of DNA motifs bound by the ets transcription-factor family member PU.1 are critically important for EIAV expression in equine macrophages. Here we identify and characterize the EIAV LTR enhancer motifs PEA-2, Lvb, Oct, and CRE, that bind to fibroblast nuclear extracts. Three of these four motifs, PEA-2, Oct, and CRE, were determined to be important for expression of the LTR in a fibroblast cell line that supports productive infection of EIAV. These motifs that are important for expression of the LTR in fibroblasts were found to be interdigitated between the PU.1 sites. We hypothesize that the combination of motif interdigitation and cell-specific usage of these motifs may be responsible for the observed EIAV LTR enhancer-region hypervariation

El Juego dramático, opción para incentivar la capacidd lingüística e interacciones comunicativas con estudiantes con discapacidad cognitiva leve

134 PáginasRecurso ElectrónicoEl juego dramático, opción para incentivar la capacidad lingüística e interacciones comunicativas con estudiantes con discapacidad cognitiva leve mejorando la inclusión en los estudiantes desde la comprensión de los fenómenos orales en el territorio escolar. El trabajo asume las artes escénicas, como proceso para desarrollar la capacidad lingüística e interacciones en los estudiantes. Este proyecto es la posibilidad de representación lúdica grupal, de expresión y de estímulo a la imaginación a través de distintas consignas que ayudan al grupo a crear escenas juntas. La posibilidad de jugar con el otro es comunicación, la posibilidad de dramatizar lo que desea, es comunicación y un camino hacia el bienestar psíquico. Las habilidades comunicativas y lingüísticas van orientadas para la atención e inclusión de niños y niñas con discapacidad cognitiva leve en la medida en que aporta el desarrollo del aprendizaje en el fortalecimiento de la expresión corporal y la improvisación de estereotipos que se dan cotidianamente en el territorio escolar. Este trabajo de grado toma a la población de cuarto de primaria con discapacidad cognitiva leve. Son 5 niños y 6 niñas. Estos niños se caracterizan por ser tímidos, sus expresiones orales son limitadas; además, presentan déficit cognoscitivo global, con dificultades de adaptación social; deficiencia de atención, lingüísticas y se evidencia la falta de integración con sus compañeros. El territorio de observación y de proyección fue la Institución educativa Fundadores Ramón Bueno y José Triana sede escuela Integradora del municipio de Girardot, Colombia, Año 2012-2014, y se contó con el apoyo de los estudiantes de los grados 4°, y el aporte del semillero de Investigación Lenguaje y Territorio Escolar.ABSTRACT. Dramatic play, option to encourage language skills and communicative interactions with students with mild cognitive impairment improving inclusion in students from understanding oral phenomena in the school grounds. The work assumes the performing arts as a process to develop linguistic ability and interactions among students. This project is the ability to group playful representation, expression and stimulate the imagination through various slogans that help the group create scenes together. The chance to play with the other is communication, the ability to dramatize what you want, is communication and a path to mental wellbeing. The communication and language skills are oriented for care and inclusion of children with mild cognitive impairment to the extent provided by the development of learning in strengthening the body expression and improvisation of stereotypes that occur daily in the school grounds. This degree work takes the population of fourth graders with mild cognitive impairment. There are 5 boys and 6 girls. These children are characterized by being timid, oral expressions are limited; also present overall cognitive deficits, difficulties with social adaptation; attention deficit, linguistic and lack of integration with peers is evident. The territory of observation and projection was the Institucion Educativa Luis Antonio Duque Peña sede San Jorge Township School Girardot, Colombia, Year 2012-2014, and had the support of students in grades 4, and the contribution seedbed Language School Research and Planning.INTRODUCCIÓN 15 1. PROBLEMA 19 1.1 DESCRIPCIÓN DEL PROBLEMA 19 1.2 PLANTEAMIENTO DEL PROBLEMA 20 1.3 FORMULACIÓN DEL PROBLEMA 21 2. JUSTIFICACIÒN 22 3. OBJETIVOS 24 3.1. OBJETIVO GENERAL 24 3.2. OBJETIVOS ESPECIFICOS 24 4. REFERENTE TEORICO 25 4.1 FENÓMENOS ORALES EN EL TERRITORIO ESCOLAR 25 4.2 VISIÓN LEGAL 25 4.3 FENÓMENOS ORALES 27 4.4 TERRITORIO 30 4.5 PENSAMIENTO Y LENGUAJE 31 4.6 DE LA COMPETENCIA Y DE LAS HABILIDADES 35 4.7 PRÁCTICAS PEDAGÓGICAS 38 4.8 PROCESOS DE LECTURA Y ESCRITURA 40 4.9 ETNOMETODOLOGÍA 42 5. METODOLOGÍA 44 5.1 TECNICAS E INSTRUMENTOS DE INVESTIGACIÓN A UTILIZAR 45 5.2 FASES DEL PROCESO DE INVESTIGACION 47 5.2.1 Primera Fase: Identificando Fenómenos Orales En La Escuela Integradora 47 5.2.2 Segunda Fase Interactuando Y Comunicando 49 5.2.3 Tercera Fase: Incrementando Habilidades Comunicativas Y Lingüísticas 50 5.2.4 Cuarta Fase. Comparto Mis Interacciones Habilidades Intelectuales Y Sociales. 50 6. ANÁLISIS DE LOS RESULTADOS 51 6.1 JUEGO DRAMÁTICO UNA ALTERNATIVA PARA FORTALECER LA DISCAPACIDAD 51 6.2 INTERACTUANDO Y COMUNICANDO 55 6.3 COMPARTO MIS INTERACCIONES Y HABILIDADES INTELECTUALES Y SOCIALES 63 CONCLUSIONES 70 RECOMENDACIONES 72 REFERENCIAS 73 ANEXOS 78ADVERTENCIA. Los autoras Shirley Cortes García , identificada con cédula de ciudadanía número 43.975.594, Ana Julieth Hernández Cruz, identificada con cédula de ciudadanía número 1.070.599.453 y Wendy Lisney Ramírez Maury, identificada con cédula de ciudadanía número 1.070.601.854, autorizan a la Universidad del Tolima la reproducción total o parcial de este documento, con la debida cita de reconocimiento de la autoría y cede a la misma universidad de los derechos patrimoniales con fines de investigación, docencia e institucionales, consagrados en el artículo 72 de la Ley 23 de 1982 y las normas que lo constituyan o modifiquen. ACUERDO 0066 DE 2003 DEL CONSEJO DE LA UNIVERSIDAD DEL TOLIM

Manipulation of P-TEFb control machinery by HIV: recruitment of P-TEFb from the large form by Tat and binding of HEXIM1 to TAR

Basal transcription of the HIV LTR is highly repressed and requires Tat to recruit the positive transcription elongation factor, P-TEFb, which functions to promote the transition of RNA polymerase II from abortive to productive elongation. P-TEFb is found in two forms in cells, a free, active form and a large, inactive complex that also contains 7SK RNA and HEXIM1 or HEXIM2. Here we show that HIV infection of cells led to the release of P-TEFb from the large form. Consistent with Tat being the cause of this effect, transfection of a FLAG-tagged Tat in 293T cells caused a dramatic shift of P-TEFb out of the large form to a smaller form containing Tat. In vitro, Tat competed with HEXIM1 for binding to 7SK, blocked the formation of the P-TEFb–HEXIM1–7SK complex, and caused the release P-TEFb from a pre-formed P-TEFb–HEXIM1–7SK complex. These findings indicate that Tat can acquire P-TEFb from the large form. In addition, we found that HEXIM1 binds tightly to the HIV 5′ UTR containing TAR and recruits and inhibits P-TEFb activity. This suggests that in the absence of Tat, HEXIM1 may bind to TAR and repress transcription elongation of the HIV LTR

Inhibition of HIV-1 replication by P-TEFb inhibitors DRB, seliciclib and flavopiridol correlates with release of free P-TEFb from the large, inactive form of the complex

<p>Abstract</p> <p>Background</p> <p>The positive transcription elongation factor, P-TEFb, comprised of cyclin dependent kinase 9 (Cdk9) and cyclin T1, T2 or K regulates the productive elongation phase of RNA polymerase II (Pol II) dependent transcription of cellular and integrated viral genes. P-TEFb containing cyclin T1 is recruited to the HIV long terminal repeat (LTR) by binding to HIV Tat which in turn binds to the nascent HIV transcript. Within the cell, P-TEFb exists as a kinase-active, free form and a larger, kinase-inactive form that is believed to serve as a reservoir for the smaller form.</p> <p>Results</p> <p>We developed a method to rapidly quantitate the relative amounts of the two forms based on differential nuclear extraction. Using this technique, we found that titration of the P-TEFb inhibitors flavopiridol, DRB and seliciclib onto HeLa cells that support HIV replication led to a dose dependent loss of the large form of P-TEFb. Importantly, the reduction in the large form correlated with a reduction in HIV-1 replication such that when 50% of the large form was gone, HIV-1 replication was reduced by 50%. Some of the compounds were able to effectively block HIV replication without having a significant impact on cell viability. The most effective P-TEFb inhibitor flavopiridol was evaluated against HIV-1 in the physiologically relevant cell types, peripheral blood lymphocytes (PBLs) and monocyte derived macrophages (MDMs). Flavopiridol was found to have a smaller therapeutic index (LD₅₀/IC₅₀) in long term HIV-1 infectivity studies in primary cells due to greater cytotoxicity and reduced efficacy at blocking HIV-1 replication.</p> <p>Conclusion</p> <p>Initial short term studies with P-TEFb inhibitors demonstrated a dose dependent loss of the large form of P-TEFb within the cell and a concomitant reduction in HIV-1 infectivity without significant cytotoxicity. These findings suggested that inhibitors of P-TEFb may serve as effective anti-HIV-1 therapies. However, longer term HIV-1 replication studies indicated that these inhibitors were more cytotoxic and less efficacious against HIV-1 in the primary cell cultures.</p

Inhibition of HIV-1 infection by aqueous extracts of Prunella vulgaris L.

<p>Abstract</p> <p>Background</p> <p>The mint family (Lamiaceae) produces a wide variety of constituents with medicinal properties. Several family members have been reported to have antiviral activity, including lemon balm (<it>Melissa officinalis </it>L.), sage (<it>Salvia </it>spp.), peppermint (<it>Mentha </it>× <it>piperita </it>L.), hyssop (<it>Hyssopus officinalis </it>L.), basil (<it>Ocimum </it>spp.) and self-heal (<it>Prunell</it>a <it>vulgaris </it>L.). To further characterize the anti-lentiviral activities of <it>Prunella vulgaris</it>, water and ethanol extracts were tested for their ability to inhibit HIV-1 infection.</p> <p>Results</p> <p>Aqueous extracts contained more anti-viral activity than did ethanol extracts, displaying potent antiviral activity against HIV-1 at sub μg/mL concentrations with little to no cellular cytotoxicity at concentrations more than 100-fold higher. Time-of-addition studies demonstrated that aqueous extracts were effective when added during the first five hours following initiation of infection, suggesting that the botanical constituents were targeting entry events. Further analysis revealed that extracts inhibited both virus/cell interactions and post-binding events. While only 40% inhibition was maximally achieved in our virus/cell interaction studies, extract effectively blocked post-binding events at concentrations similar to those that blocked infection, suggesting that it was targeting of these latter steps that was most important for mediating inhibition of virus infectivity.</p> <p>Conclusions</p> <p>We demonstrate that aqueous <it>P. vulgaris </it>extracts inhibited HIV-1 infectivity. Our studies suggest that inhibition occurs primarily by interference of early, post-virion binding events. The ability of aqueous extracts to inhibit early events within the HIV life cycle suggests that these extracts, or purified constituents responsible for the antiviral activity, are promising microbicides and/or antivirals against HIV-1.</p

Inhibition of lentivirus replication by aqueous extracts of Prunella vulgaris

<p>Abstract</p> <p>Background</p> <p>Various members of the mint family have been used historically in Chinese and Native American medicine. Many of these same family members, including <it>Prunella vulgaris</it>, have been reported to have anti-viral activities. To further characterize the anti-lentiviral activities of <it>P. vulgaris</it>, water and ethanol extractions were tested for their ability to inhibit equine infectious anemia virus (EIAV) replication.</p> <p>Results</p> <p>Aqueous extracts contained more anti-viral activity than did ethanol extracts, displaying potent anti-lentiviral activity against virus in cell lines as well as in primary cell cultures with little to no cellular cytotoxicity. Time-of-addition studies demonstrated that the extracts were effective when added during the first four h of the viral life cycle, suggesting that the botanical constituents were targeting the virion itself or early entry events. Further analysis revealed that the extracts did not destroy EIAV virion integrity, but prevented viral particles from binding to the surface of permissive cells. Modest levels of anti-EIAV activity were also detected when the cells were treated with the extracts prior to infection, indicating that anti-EIAV botanical constituents could interact with both viral particles and permissive cells to interfere with infectivity. Size fractionation of the extract demonstrated that eight of the nine fractions generated from aqueous extracts displayed anti-viral activity. Separation of ethanol soluble and insoluble compounds in the eight active fractions revealed that ethanol-soluble constituents were responsible for the anti-viral activity in one fraction whereas ethanol-insoluble constituents were important for the anti-viral activity in two of the other fractions. In three of the five fractions that lost activity upon sub-fractionation, anti-viral activity was restored upon reconstitution of the fractions, indicating that synergistic anti-viral activity is present in several of the fractions.</p> <p>Conclusion</p> <p>Our findings indicate that multiple <it>Prunella </it>constituents have profound anti-viral activity against EIAV, providing additional evidence of the broad anti-viral abilities of these extracts. The ability of the aqueous extracts to prevent entry of viral particles into permissive cells suggests that these extracts may function as promising microbicides against lentiviruses.</p

Hypericum in infection: Identification of anti-viral and anti-inflammatory constituents

The Iowa Center for Research on Botanical Dietary Supplements seeks to optimize Echinacea, Hypericum, and Prunella botanical supplements for human-health benefit, emphasizing anti-viral, anti-inflammatory, and anti-pain activities. This mini-review reports on ongoing studies on Hypericum. The Center uses the genetically diverse, well-documented Hypericum populations collected and maintained at the USDA-ARS North Central Regional Plant Introduction Station (NCRPIS), and the strength of research in synthetic chemistry at Iowa State University to tap natural diversity, to help discover key constituents and interactions among constituents that impact bioactivity and toxicity. The NCRPIS has acquired more than 180 distinct populations of Hypericum, with a focus on Hypericum perforatum L. (Hypericaceae), representing about 13% of currently recognized taxa. Center chemists have developed novel synthetic pathways for key flavones, acyl phloroglucinols, hyperolactones, and a tetralin that have been found in Hypericum, and these compounds are used as standards and for bioactivity studies. Both light-dependent and light-independent anti-viral activities have been identified by using bioactivity-guided fractionation of H. perforatum and a HIV-1 infection test system. Our Center has focused on light-independent activity, potentially due to novel chemicals, and polar fractions are undergoing further fractionation. Anti-inflammatory activity has been found to be light-independent, and fractionation of a flavonoid-rich extract revealed four compounds (amentoflavone, chlorogenic acid, pseudohypericin, and quercetin) that interacted in the light to inhibit lipopolysaccharide-induced prostaglandin E2 activity. The Center continues to explore novel populations of H. perforatum and related species to identify constituents and interactions of constituents that contribute to potential health benefits related to infection

Identification of light-independent inhibition of human immunodeficiency virus-1 infection through bioguided fractionation of Hypericum perforatum

<p>Abstract</p> <p>Background</p> <p>Light-dependent activities against enveloped viruses in St. John's Wort (<it>Hypericum perforatum</it>) extracts have been extensively studied. In contrast, light-independent antiviral activity from this species has not been investigated.</p> <p>Results</p> <p>Here, we identify the light-independent inhibition of human immunodeficiency virus-1 (HIV-1) by highly purified fractions of chloroform extracts of <it>H. perforatum</it>. Both cytotoxicity and antiviral activity were evident in initial chloroform extracts, but bioassay-guided fractionation produced fractions that inhibited HIV-1 with little to no cytotoxicity. Separation of these two biological activities has not been reported for constituents responsible for the light-dependent antiviral activities. Antiviral activity was associated with more polar subfractions. GC/MS analysis of the two most active subfractions identified 3-hydroxy lauric acid as predominant in one fraction and 3-hydroxy myristic acid as predominant in the other. Synthetic 3-hydroxy lauric acid inhibited HIV infectivity without cytotoxicity, suggesting that this modified fatty acid is likely responsible for observed antiviral activity present in that fraction. As production of 3-hydroxy fatty acids by plants remains controversial, <it>H. perforatum </it>seedlings were grown sterilely and evaluated for presence of 3-hydroxy fatty acids by GC/MS. Small quantities of some 3-hydroxy fatty acids were detected in sterile plants, whereas different 3-hydroxy fatty acids were detected in our chloroform extracts or field-grown material.</p> <p>Conclusion</p> <p>Through bioguided fractionation, we have identified that 3-hydroxy lauric acid found in field grown <it>Hypericum perforatum </it>has anti-HIV activity. This novel anti-HIV activity can be potentially developed into inexpensive therapies, expanding the current arsenal of anti-retroviral agents.</p