56 research outputs found

    Distribution and Redistribution of HIV-1 Nucleocapsid Protein in Immature, Mature, and Integrase-Inhibited Virions: a Role for Integrase in Maturation

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    During virion maturation, HIV-1 capsid protein assembles into a conical core containing the viral ribonucleoprotein (vRNP) complex, thought to be composed mainly of the viral RNA and nucleocapsid protein (NC). After infection, the viral RNA is reverse transcribed into double-stranded DNA, which is then incorporated into host chromosomes by integrase (IN) catalysis. Certain IN mutations (class II) and antiviral drugs (allosteric IN inhibitors [ALLINIs]) adversely affect maturation, resulting in virions that contain “eccentric condensates,” electron-dense aggregates located outside seemingly empty capsids. Here we demonstrate that in addition to this mislocalization of electron density, a class II IN mutation and ALLINIs each increase the fraction of virions with malformed capsids (from ∌12% to ∌53%). Eccentric condensates have a high NC content, as demonstrated by “tomo-bubblegram” imaging, a novel labeling technique that exploits the susceptibility of NC to radiation damage. Tomo-bubblegrams also localized NC inside wild-type cores and lining the spherical Gag shell in immature virions. We conclude that eccentric condensates represent nonpackaged vRNPs and that either genetic or pharmacological inhibition of IN can impair vRNP incorporation into mature cores. Supplying IN in trans as part of a Vpr-IN fusion protein partially restored the formation of conical cores with internal electron density and the infectivity of a class II IN deletion mutant virus. Moreover, the ability of ALLINIs to induce eccentric condensate formation required both IN and viral RNA. Based on these observations, we propose a role for IN in initiating core morphogenesis and vRNP incorporation into the mature core during HIV-1 maturation

    ICAR: endoscopic skull‐base surgery

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    Chronic Nicotine Exposure In Vivo and In Vitro Inhibits Vitamin B1 (Thiamin) Uptake by Pancreatic Acinar Cells.

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    Thiamin (vitamin B1), a member of the water-soluble family of vitamins, is essential for normal cellular functions; its deficiency results in oxidative stress and mitochondrial dysfunction. Pancreatic acinar cells (PAC) obtain thiamin from the circulation using a specific carrier-mediated process mediated by both thiamin transporters -1 and -2 (THTR-1 and THTR-2; encoded by the SLC19A2 and SLC19A3 genes, respectively). The aim of the current study was to examine the effect of chronic exposure of mouse PAC in vivo and human PAC in vitro to nicotine (a major component of cigarette smoke that has been implicated in pancreatic diseases) on thiamin uptake and to delineate the mechanism involved. The results showed that chronic exposure of mice to nicotine significantly inhibits thiamin uptake in murine PAC, and that this inhibition is associated with a marked decrease in expression of THTR-1 and THTR-2 at the protein, mRNA and hnRNAs level. Furthermore, expression of the important thiamin-metabolizing enzyme, thiamin pyrophosphokinase (TPKase), was significantly reduced in PAC of mice exposed to nicotine. Similarly, chronic exposure of cultured human PAC to nicotine (0.5 ÎŒM, 48 h) significantly inhibited thiamin uptake, which was also associated with a decrease in expression of THTR-1 and THTR-2 proteins and mRNAs. This study demonstrates that chronic exposure of PAC to nicotine impairs the physiology and the molecular biology of the thiamin uptake process. Furthermore, the study suggests that the effect is, in part, mediated through transcriptional mechanism(s) affecting the SLC19A2 and SLC19A3 genes

    Can We Use the Relationship Between Within-Field Elevation and NDVI as an Indicator of Drought-Stress?

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    Large farmers’ datasets can help shed light on agroecological processes if used in the context of hypothesis testing. Here we used an anonymized set of data from the geoplatform Akkerweb to better understand the correlation between within-field elevation and normalized differential vegetation index (NDVI, a proxy for biomass). The dataset included 3249 Dutch potato fields, for each of which the cultivar, the field polygon, the year of cultivation and the soil type (clay or sandy) was known. We hypothesize that under dry conditions such correlation is negative, meaning that the lowest portions of the field have more biomass because of water redistribution. From the data, we observed that in dry periods, such as the summer of 2018, the correlation was negative in sandy soils. Furthermore, we observed that early cultivars show a weaker correlation between NDVI and elevation than late cultivars, possibly because early cultivar escape part of the long dry summer spells. We conclude that the correlation between NDVI and elevation may be a useful indicator of drought stress, and deviations from the norm may be useful to evaluate the resistance to drought of individual cultivars

    Clinical Trial Awareness Among Racial/Ethnic Minorities in HINTS 2007: Sociodemographic, Attitudinal, and Knowledge Correlates

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    The purpose of this study was (1) to examine the association of race/ethnicity on clinical trial awareness, controlling for several sociodemographic, attitudinal, and knowledge variables, and (2) to inform future communication campaigns to increase clinical trial awareness and participation. Secondary analysis was conducted among 6,754 Hispanic, Black, and White adult respondents to the National Cancer Institute's 2007 Health Information National Trends Survey (HINTS). The dependent variable was awareness of clinical trials. Logistic regression was used to examine possible correlates of clinical trial awareness including sociodemographics, trust of sources of health information, beliefs about safety of health information, family/personal history of cancer, health seeking information, and awareness of three health agencies. Compared with Whites, Blacks and Hispanics were significantly less likely to have heard of a clinical trial. Other significant correlates of clinical trial awareness included education, income, belief that health information is safely guarded, family history of cancer, awareness of the Centers for Disease control, trust of health information from the Internet and charitable organizations, and distrust of health information from religious institutions. Blacks and Hispanics are significantly less aware of clinical trials. Campaigns that exploit unique beliefs and delivery channels for racial/ethnic subgroups should be considered
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