127 research outputs found

    Occurrence of Volatile Organic Compounds and Extrafloral Nectaries in Tropical Rainforest Species in Danum Valley Conservation Area, Sabah, Malaysia

    Get PDF
    Plants synthesize numerous classes of secondary metabolites that are crucial in plant defense. Two of the common but non-ubiquitous defenses are the emission of volatile organic compounds (VOCs) and production of extrafloral nectaries (EFN). This study investigates the occurrence of emission of VOC and production of EFN in forest species in Danum Valley Conservation Area, Sabah, Malaysia. From the 165 species screened, 131 species were found to emit VOC while 41 species were EFN-bearing plants. There are 34 species that are both emitting VOC and producing EFN, while 97 species were found to be emitting VOC with no EFN observed. On the other hand, there are 7 species that were EFN bearing but non-VOC emitter, while 27 species were neither emitting VOC nor producing EFN. All 12 dipterocarp species were observed to emit VOC, of these 3 are non-EFN bearing. VOC emissions were further classified into isoprene (C5) and monoterpene (C10) compounds. There are 46 species that were detected to emit both isoprene and monoterpenes, while there are more exclusive monoterpene emitters (62 species) than isoprene-only emitters (23 species). This study showcased the ability of plants to produce a wide array of secondary metabolites as plant defense making them successfully adapt to the complexities of tropical rainforest ecosystem

    Anaplasma marginale Actively Modulates Vacuolar Maturation During Intracellular Infection of Its Tick Vector, Dermacentor andersoni

    Get PDF
    ABSTRACT Tick-borne transmission of bacterial pathogens in the order Rickettsiales is responsible for diverse infectious diseases, many of them severe, in humans and animals. Transmission dynamics differ among these pathogens and are reflected in the pathogen-vector interaction. Anaplasma marginale has been shown to establish and maintain infectivity within Dermacentor spp. for weeks to months while escaping the complex network of vacuolar peptidases that are responsible for digestion ofthe tick blood meal. How this prolonged maintenance of infectivity in a potentially hostile environment is achieved has been unknown. Using the natural vector Dermacentor andersoni, we demonstrated that A. marginale-infected tick vacuoles (AmVs) concurrently recruit markers of the early endosome (Rab5), recycling endosome (Rab4 and Rab11), and late endosome (Rab7), are maintained near neutral pH, do not fuse with lysosomes, exclude the protease cathepsin L, and engage the endoplasmic reticulum and Golgi apparatus for up to 21 days post infection. Maintenance of this safe vacuolar niche requires active A. marginale protein synthesis; in its absence, the AmVs mature into acidic, protease-active phagolysosomes. Identification of this bacterially directed modeling of the tick midgut endosome provides a mechanistic basis for examination of the differences in transmission efficiency observed among A. marginale strains and among vector populations. IMPORTANCE Ticks transmit a variety of intracellular bacterial pathogens that cause significant diseases in humans and animals. For successful transmission, these bacterial pathogens must first gain entry into the tick midgut digestive cells, avoid digestion, and establish a replicative niche without harming the tick vector. Little is known about how this replicative niche is established and maintained. Using the ruminant pathogen A. marginale and its natural tick vector, D. andersoni, this study characterized the features of the A. marginale niche in the tick midgut and demonstrates that A. marginale protein synthesis is required for the maintenance of this niche. This work opens a new line of inquiry about the pathogen effectors and their targets within the tick that mediate tick pathogen interactions and ultimately serve as the determinants of pathogen success

    The Pathogen-Occupied Vacuoles of Anaplasma phagocytophilum and Anaplasma marginale Interact with the Endoplasmic Reticulum

    Get PDF
    The genus Anaplasma consists of tick-transmitted obligate intracellular bacteria that invade white or red blood cells to cause debilitating and potentially fatal infections. A. phagocytophilum, a human and veterinary pathogen, infects neutrophils to cause granulocytic anaplasmosis. A. marginale invades bovine erythrocytes. Evidence suggests that both species may also infect endothelial cells in vivo. In mammalian and arthropod host cells, A. phagocytophilum and A. marginale reside in host cell derived pathogen-occupied vacuoles (POVs). While it was recently demonstrated that the A. phagocytophilum-occupied vacuole (ApV) intercepts membrane traffic from the trans-Golgi network, it is unclear if it or the A. marginale-occupied vacuole (AmV) interacts with other secretory organelles. Here, we demonstrate that the ApV and AmV extensively interact with the host endoplasmic reticulum (ER) in endothelial, myeloid, and/or tick cells. ER lumen markers, calreticulin, and protein disulfide isomerase, and the ER membrane marker, derlin-1, were pronouncedly recruited to the peripheries of both POVs. ApV association with the ER initiated early and continued throughout the infection cycle. Both the ApV and AmV interacted with the rough ER and smooth ER. However, only derlin-1-positive rough ER derived vesicles were delivered into the ApV lumen where they localized with intravacuolar bacteria. Transmission electron microscopy identified multiple ER-POV membrane contact sites on the cytosolic faces of both species\u27 vacuoles that corresponded to areas on the vacuoles\u27 lumenal faces where intravacuolar Anaplasma organisms closely associated. A. phagocytophilum is known to hijack Rab10, a GTPase that regulates ER dynamics and morphology. Yet, ApV-ER interactions were unhindered in cells in which Rab10 had been knocked down, demonstrating that the GTPase is dispensable for the bacterium to parasitize the ER. These data establish the ApV and AmV as pathogen-host interfaces that directly engage the ER in vertebrate and invertebrate host cells and evidence the conservation of ER parasitism between two Anaplasma species

    Occurrence of volatile organic compounds and extrafloral nectaries in tropical rainforest species in Danum Valley Conservation Area, Sabah, Malaysia

    Get PDF
    Plants synthesize numerous classes of secondary metabolites that are crucial in plant defense. Two of the common but non-ubiquitous defenses are the emission of volatile organic compounds (VOCs) and production of extrafloral nectaries (EFN). This study investigates the occurrence of emission of VOC and production of EFN in forest species in Danum Valley Conservation Area, Sabah, Malaysia. From the 165 species screened, 131 species were found to emit VOC while 41 species were EFN-bearing plants. There are 34 species that are both emitting VOC and producing EFN, while 97 species were found to be emitting VOC with no EFN observed. On the other hand, there are 7 species that were EFN bearing but non-VOC emitter, while 27 species were neither emitting VOC nor producing EFN. All 12 dipterocarp species were observed to emit VOC, of these 3 are non-EFN bearing. VOC emissions were further classified into isoprene (C5) and monoterpene (C10) compounds. There are 46 species that were detected to emit both isoprene and monoterpenes, while there are more exclusive monoterpene emitters (62 species) than isoprene-only emitters (23 species). This study showcased the ability of plants to produce a wide array of secondary metabolites as plant defense making them successfully adapt to the complexities of tropical rainforest ecosystem

    Identification of recruitment and retention strategies for rehabilitation professionals in Ontario, Canada: results from expert panels

    Get PDF
    <p>Abstract</p> <p>Background</p> <p>Demand for rehabilitation services is expected to increase due to factors such as an aging population, workforce pressures, rise in chronic and complex multi-system disorders, advances in technology, and changes in interprofessional health service delivery models. However, health human resource (HHR) strategies for Canadian rehabilitation professionals are lagging behind other professional groups such as physicians and nurses. The objectives of this study were: 1) to identify recruitment and retention strategies of rehabilitation professionals including occupational therapists, physical therapists and speech language pathologists from the literature; and 2) to investigate both the importance and feasibility of the identified strategies using expert panels amongst HHR and education experts.</p> <p>Methods</p> <p>A review of the literature was conducted to identify recruitment and retention strategies for rehabilitation professionals. Two expert panels, one on <it>Recruitment and Retention </it>and the other on <it>Education </it>were convened to determine the importance and feasibility of the identified strategies. A modified-delphi process was used to gain consensus and to rate the identified strategies along these two dimensions.</p> <p>Results</p> <p>A total of 34 strategies were identified by the <it>Recruitment and Retention </it>and <it>Education </it>expert panels as being important and feasible for the development of a HHR plan for recruitment and retention of rehabilitation professionals. Seven were categorized under the <it>Quality of Worklife and Work Environment </it>theme, another seven in <it>Financial Incentives and Marketing</it>, two in <it>Workload and Skill Mix</it>, thirteen in <it>Professional Development </it>and five in <it>Education and Training</it>.</p> <p>Conclusion</p> <p>Based on the results from the expert panels, the three major areas of focus for HHR planning in the rehabilitation sector should include strategies addressing <it>Quality of Worklife and Work Environment</it>, <it>Financial Incentives and Marketing </it>and <it>Professional Development</it>.</p

    Evidence that breast cancer risk at the 2q35 locus is mediated through IGFBP5 regulation.

    Get PDF
    GWAS have identified a breast cancer susceptibility locus on 2q35. Here we report the fine mapping of this locus using data from 101,943 subjects from 50 case-control studies. We genotype 276 SNPs using the 'iCOGS' genotyping array and impute genotypes for a further 1,284 using 1000 Genomes Project data. All but two, strongly correlated SNPs (rs4442975 G/T and rs6721996 G/A) are excluded as candidate causal variants at odds against >100:1. The best functional candidate, rs4442975, is associated with oestrogen receptor positive (ER+) disease with an odds ratio (OR) in Europeans of 0.85 (95% confidence interval=0.84-0.87; P=1.7 × 10(-43)) per t-allele. This SNP flanks a transcriptional enhancer that physically interacts with the promoter of IGFBP5 (encoding insulin-like growth factor-binding protein 5) and displays allele-specific gene expression, FOXA1 binding and chromatin looping. Evidence suggests that the g-allele confers increased breast cancer susceptibility through relative downregulation of IGFBP5, a gene with known roles in breast cell biology

    Publisher Correction: Evidence that breast cancer risk at the 2q35 locus is mediated through IGFBP5 regulation.

    Get PDF
    This corrects the article DOI: 10.1038/ncomms5999

    Genetic variation at CYP3A is associated with age at menarche and breast cancer risk : a case-control study

    Get PDF
    Abstract Introduction We have previously shown that a tag single nucleotide polymorphism (rs10235235), which maps to the CYP3A locus (7q22.1), was associated with a reduction in premenopausal urinary estrone glucuronide levels and a modest reduction in risk of breast cancer in women age ≀50 years. Methods We further investigated the association of rs10235235 with breast cancer risk in a large case control study of 47,346 cases and 47,570 controls from 52 studies participating in the Breast Cancer Association Consortium. Genotyping of rs10235235 was conducted using a custom Illumina Infinium array. Stratified analyses were conducted to determine whether this association was modified by age at diagnosis, ethnicity, age at menarche or tumor characteristics. Results We confirmed the association of rs10235235 with breast cancer risk for women of European ancestry but found no evidence that this association differed with age at diagnosis. Heterozygote and homozygote odds ratios (ORs) were OR = 0.98 (95% CI 0.94, 1.01; P = 0.2) and OR = 0.80 (95% CI 0.69, 0.93; P = 0.004), respectively (P trend = 0.02). There was no evidence of effect modification by tumor characteristics. rs10235235 was, however, associated with age at menarche in controls (P trend = 0.005) but not cases (P trend = 0.97). Consequently the association between rs10235235 and breast cancer risk differed according to age at menarche (P het = 0.02); the rare allele of rs10235235 was associated with a reduction in breast cancer risk for women who had their menarche age ≄15 years (ORhet = 0.84, 95% CI 0.75, 0.94; ORhom = 0.81, 95% CI 0.51, 1.30; P trend = 0.002) but not for those who had their menarche age ≀11 years (ORhet = 1.06, 95% CI 0.95, 1.19, ORhom = 1.07, 95% CI 0.67, 1.72; P trend = 0.29). Conclusions To our knowledge rs10235235 is the first single nucleotide polymorphism to be associated with both breast cancer risk and age at menarche consistent with the well-documented association between later age at menarche and a reduction in breast cancer risk. These associations are likely mediated via an effect on circulating hormone levels
    • 

    corecore