Memorial University of Newfoundland

About: Memorial University of Newfoundland is a education organization based out in St. John's, Newfoundland and Labrador, Canada. It is known for research contribution in the topics: Population & Context (language use). The organization has 13818 authors who have published 27785 publications receiving 743594 citations. The organization is also known as: Memorial University & Memorial University of Newfoundland and Labrador.

Nutrition and immunology: from the clinic to cellular biology and back again.

Abstract: Diet and immunity have been known to be linked to each other for centuries. In the last 30 years systematic studies have confirmed that nutrient deficiencies impair immune response and lead to frequent severe infections resulting in increased mortality, especially in children. Protein-energy malnutrition results in reduced number and functions of T-cells, phagocytic cells and secretory immunoglobulin A antibody response. In addition, levels of many complement components are reduced. Similar findings have been reported for moderate deficiencies of individual nutrients such as trace minerals and vitamins, particularly Zn, Fe, Se, vitamins A, B6, C and E. For example, Zn deficiency is associated with profound impairment of cell-mediated immunity such as lymphocyte stimulation response, decreased CD4+:CD8+ cells, and decreased chemotaxis of phagocytes. In addition, the level of thymulin, which is a Zn-dependent hormone, is markedly decreased. The use of nutrient supplements, singly or in combination, stimulates immune response and may result in fewer infections, particularly in the elderly, low-birth-weight infants and malnourished critically-ill patients in hospitals. The interactions between nutrition and the immune system are of clinical, practical and public health importance.

Expression of Drosophila FOXO regulates growth and can phenocopy starvation.

Abstract: Components of theinsulin signaling pathway are important regulators of growth. TheFOXO (forkhead box, sub-group "O") transcriptionfactors regulate cellular processes under conditions of low levelsof insulin signaling. Studies in mammalian cell culture show thatactivation of FOXO transcription factors causes cell death or cellcycle arrest. The Caenorhabiditis elegans homologue ofFOXO, Daf-16, is required for the formation of dauer larvae in responseto nutritional stress. In addition, FOXO factors have been implicatedin stress resistance and longevity. We have identifiedthe Drosophila melanogaster homologue of FOXO (dFOXO),which is conserved in amino acid sequence compared with the mammalianFOXO homologues and Daf-16. Expression of dFOXO during early larvaldevelopment causes inhibition of larval growth and alterations infeeding behavior. Inhibition of larval growth is reversible upondiscontinuation of dFOXO expression. Expression of dFOXO duringthe third larval instar or at low levels during development leadsto the generation of adults that are reduced in size. Analysis ofthe wings and eyes of these small flies indicates that the reductionin size is due to decreases in cell size and cell number. Overexpressionof dFOXO in the developing eye leads to a characteristic phenotypewith reductions in cell size and cell number. This phenotype canbe rescued by co-expression of upstream insulin signaling components,dPI3K and dAkt, however, this rescue is not seen when FOXO is mutatedto a constitutively active form. dFOXO is conservedin both sequence and regulatory mechanisms when compared with otherFOXO homologues. The establishment of Drosophila as a model forthe study of FOXO transcription factors should prove beneficialto determining the biological role of these signaling molecules.The alterations in larval development seen upon overexpression ofdFOXO closely mimic the phenotypic effects of starvation, suggestinga role for dFOXO in the response to nutritional adversity. Thiswork has implications in the understanding of cancer and insulinrelated disorders, such as diabetes and obesity.

An ocean-basin-wide mark-recapture study of the North Atlantic humpback whale (Megaptera novaeangliae)

Abstract: Although much is known about the humpback whale, Megaptera novaeangliae, regional studies have been unable to answer several questions that are central to the conservation and management of this endangered species. To resolve uncertainties about population size, as well as the spatial and genetic structure of the humpback whale population in the North Atlantic, we conducted a two-year ocean-basin-wide photographic and biopsy study in 1992-1993. Photographic and skin-biopsy sampling was conducted of animals in feeding and breeding areas throughout most of the range of this species in the North Atlantic, from the West Indies breeding grounds through all known feeding areas as far north as arctic Norway. A standardized sampling protocol was designed to maximize sample sizes while attempting to ensure equal probability of sampling, so that estimates of abundance would be as accurate and as precise as possible. During 666 d at sea aboard 28 vessels, 4,207 tail fluke photographs and 2,326 skin biopsies were collected. Molecular analyses of all biopsies included determination of sex, genotype using six microsatellite loci, and mitochondrial control region sequence. The photographs and microsatellite loci were used to identify 2,998 and 2,015 individual whales, respectively. Previously published results from this study have addressed spatial distribution, migration, and genetic relationships. Here, we present new estimates of total abundance in this ocean using photographic data, as well as overall and sex-specific estimates using biopsy data. We identify several potential sampling biases using only breeding-area samples and report a consistent mark-recapture estimate of oceanwide abundance derived from photographic identification, using both breeding and feeding-area data, of 10,600 (95% confidence interval 9,300-12,100). We also report a comparable, but less precise, biopsy-based estimate of 10,400 (95% confidence interval of 8,000-13,600). These estimates are significantly larger and more precise than estimates made for the 1980s, potentially reflecting population growth. In contrast, significantly lower and less consistent estimates were obtained using between-feeding-area or between-breeding-area sampling. Reasons for the lower estimates using the results of sampling in the same areas in subsequent years are discussed. Overall, the results of this ocean-basin-wide study demonstrate that an oceanwide approach to population assessment of baleen whales is practicable and results in a more comprehensive understanding of population abundance and biology than can be gained from smaller-scale efforts.

Major histocompatibility complex associations of ankylosing spondylitis are complex and involve further epistasis with ERAP1.

Abstract: Ankylosing spondylitis (AS) is a common, highly heritable, inflammatory arthritis for which HLA-B*27 is the major genetic risk factor, although its role in the aetiology of AS remains elusive. To better understand the genetic basis of the MHC susceptibility loci, we genotyped 7,264 MHC SNPs in 22,647 AS cases and controls of European descent. We impute SNPs, classical HLA alleles and amino-acid residues within HLA proteins, and tested these for association to AS status. Here we show that in addition to effects due to HLA-B*27 alleles, several other HLA-B alleles also affect susceptibility. After controlling for the associated haplotypes in HLA-B, we observe independent associations with variants in the HLA-A, HLA-DPB1 and HLA-DRB1 loci. We also demonstrate that the ERAP1 SNP rs30187 association is not restricted only to carriers of HLA-B*27 but also found in HLA-B*40:01 carriers independently of HLA-B*27 genotype.