196 research outputs found

    Syntaxin 16 is a master recruitment factor for cytokinesis

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    Recently it was shown that both recycling endosome and endosomal sorting complex required for transport (ESCRT) components are required for cytokinesis, in which they are believed to act in a sequential manner to bring about secondary ingression and abscission, respectively. However, it is not clear how either of these complexes is targeted to the midbody and whether their delivery is coordinated. The trafficking of membrane vesicles between different intracellular organelles involves the formation of soluble N-ethylmalei­mide–sensitive factor attachment protein receptor (SNARE) complexes. Although membrane traffic is known to play an important role in cytokinesis, the contribution and identity of intracellular SNAREs to cytokinesis remain unclear. Here we demonstrate that syntaxin 16 is a key regulator of cytokinesis, as it is required for recruitment of both recycling endosome–associated Exocyst and ESCRT machinery during late telophase, and therefore that these two distinct facets of cytokinesis are inextricably linked

    Increased Resin Collection after Parasite Challenge: A Case of Self-Medication in Honey Bees?

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    The constant pressure posed by parasites has caused species throughout the animal kingdom to evolve suites of mechanisms to resist infection. Individual barriers and physiological defenses are considered the main barriers against parasites in invertebrate species. However, behavioral traits and other non-immunological defenses can also effectively reduce parasite transmission and infection intensity. In social insects, behaviors that reduce colony-level parasite loads are termed “social immunity.” One example of a behavioral defense is resin collection. Honey bees forage for plant-produced resins and incorporate them into their nest architecture. This use of resins can reduce chronic elevation of an individual bee's immune response. Since high activation of individual immunity can impose colony-level fitness costs, collection of resins may benefit both the individual and colony fitness. However the use of resins as a more direct defense against pathogens is unclear. Here we present evidence that honey bee colonies may self-medicate with plant resins in response to a fungal infection. Self-medication is generally defined as an individual responding to infection by ingesting or harvesting non-nutritive compounds or plant materials. Our results show that colonies increase resin foraging rates after a challenge with a fungal parasite (Ascophaera apis: chalkbrood or CB). Additionally, colonies experimentally enriched with resin had decreased infection intensities of this fungal parasite. If considered self-medication, this is a particularly unique example because it operates at the colony level. Most instances of self-medication involve pharmacophagy, whereby individuals change their diet in response to direct infection with a parasite. In this case with honey bees, resins are not ingested but used within the hive by adult bees exposed to fungal spores. Thus the colony, as the unit of selection, may be responding to infection through self-medication by increasing the number of individuals that forage for resin

    Genetic Characterization of Human T-Cell Lymphotropic Virus Type 1 in Mozambique: Transcontinental Lineages Drive the HTLV-1 Endemic

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    Human T-cell lymphotropic virus type 1 (HTLV-1) is the causative agent of Adult T-Cell Leukemia/Lymphoma (ATL), the Tropical Spastic Paraparesis/HTLV-1-associated Myelopathy (TSP/HAM) and other inflammatory diseases, including dermatitis, uveitis, and myositis. It is estimated that 2–8% of the infected persons will develop a HTLV-1-associated disease during their lifetimes, frequently TSP/HAM. Thus far, there is not a specific treatment to this progressive and chronic disease. HTLV-1 has means of three transmission: (i) from mother to child during prolonged breastfeeding, (ii) between sexual partners and (iii) through blood transfusion. HTLV-1 has been characterized in 7 subtypes and the geographical distribution and the clinical impact of this infection is not well known, mainly in African population. HTLV-1 is endemic in sub-Saharan Africa. Mozambique is a country of southeastern Africa where TSP/HAM cases were reported. Recently, our group estimated the HTLV prevalence among Mozambican blood donors as 0.9%. In this work we performed a genetic analysis of HTLV-1 in blood donors and HIV/HTLV co-infected patients from Maputo, Mozambique. Our results showed the presence of three HTLV-1 clusters within the Cosmopolitan/Transcontinental subtype/subgroup. The differential rates of HIV-1/HTLV-1 co-infection in the three HTLV-1 clusters demonstrated the dynamic of the two viruses and the need for implementation of control measures focusing on both retroviruses

    The Australian Racism, Acceptance, and Cultural-Ethnocentrism Scale (RACES): item response theory findings

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    BACKGROUND: Racism and associated discrimination are pervasive and persistent challenges with multiple cumulative deleterious effects contributing to inequities in various health outcomes. Globally, research over the past decade has shown consistent associations between racism and negative health concerns. Such research confirms that race endures as one of the strongest predictors of poor health. Due to the lack of validated Australian measures of racist attitudes, RACES (Racism, Acceptance, and Cultural-Ethnocentrism Scale) was developed. METHODS: Here, we examine RACES’ psychometric properties, including the latent structure, utilising Item Response Theory (IRT). Unidimensional and Multidimensional Rating Scale Model (RSM) Rasch analyses were utilised with 296 Victorian primary school students and 182 adolescents and 220 adults from the Australian community. RESULTS: RACES was demonstrated to be a robust 24-item three-dimensional scale of Accepting Attitudes (12 items), Racist Attitudes (8 items), and Ethnocentric Attitudes (4 items). RSM Rasch analyses provide strong support for the instrument as a robust measure of racist attitudes in the Australian context, and for the overall factorial and construct validity of RACES across primary school children, adolescents, and adults. CONCLUSIONS: RACES provides a reliable and valid measure that can be utilised across the lifespan to evaluate attitudes towards all racial, ethnic, cultural, and religious groups. A core function of RACES is to assess the effectiveness of interventions to reduce community levels of racism and in turn inequities in health outcomes within Australia. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12939-016-0338-4) contains supplementary material, which is available to authorized users
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