Genetic portrait of Lisboa immigrant population from Cabo Verde with mitochondrial DNA analysis

Journal of Genetics -     

Phylogeny and infrageneric classification of Correa Andrews (Rutaceae) on the basis of nuclear and chloroplast DNA

This paper presents phylogenies of the small but ecologically and horticulturally important Australian genus Correa (Rutaceae). Consensus phylogenies generated using parsimony were congruent with their counterparts generated by Bayesian analysis, although usually less well resolved. The phylogeny generated from the second internal transcribed spacer region of the nuclear ribosomal DNA supported the monophyly of Correa and identified two well supported clades (one comprising C. lawrenceana and C. baeuerlenii and the other containing all other species of the genus). Phylogenetic reconstructions based on the combined trnL-trnF spacer and the trnK intron (including the matK gene) regions of chloroplast DNA also supported the monophyly of Correa and of the C. lawrenceana/C. baeuerlenii clade, but the topology among the other species differed markedly from that in the ITS-based phylogeny. The major clades identified in the chloroplast phylogenies seemed to follow geographic patterns rather than species boundaries, with different samples of C. glabra bearing chloroplast genotypes from different clades. These patterns are likely to be because of independent evolution of the chloroplast and nuclear genomes, and are typical of cases of introgressive hybridisation among species or incomplete lineage sorting of chloroplast genomes leading to incongruence between chloroplast and nuclear phylogenies. Thus, the phylogenies based on nuclear DNA should reflect species relations better than the chloroplast phylogeny in Correa, and we propose a new subgeneric classification of the genus on the basis of the ITS-based phylogeny and morphology. Correa subgenus Persistens Othman, Duretto and G.J. Jord., containing C. lawrenceana and C. baeuerlenii, is formally described.     

Differential requirement of lipid rafts for FcγRIIA mediated effector activities

Immunoglobulin G (IgG) dependent activities are important in host defense and autoimmune diseases. Various cell types including macrophages and neutrophils contribute to pathogen destruction and tissue damage through binding of IgG to Fcγ receptors (FcγR). One member of this family, FcγRIIA, is a transmembrane glycoprotein known to mediate binding and internalization of IgG-containing targets. FcγRIIA has been observed to translocate into lipids rafts upon binding IgG-containing targets. We hypothesize that lipid rafts participate to different extents in binding and internalizing targets of different sizes. We demonstrate that disruption of lipid rafts with 8 mM methyl-β-cyclodextrin (MβCD) nearly abolishes binding (91% reduction) and phagocytosis (60% reduction) of large IgG-coated targets. Conversely, binding and internalization of small IgG-complexes is less dependent on lipid rafts (49% and 17% inhibition at 8 mM MβCD, respectively). These observations suggest that differences between phagocytosis and endocytosis may arise as early as the initial stages of ligand recognition.     

Unconditional hospitality: HIV, ethics and the refugee 'problem'

Refugees, as forced migrants, have suffered displacement under conditions not of their own choosing. In 2000 there were thought to be 22 million refugees of whom 6 million were HIV positive. While the New Zealand government has accepted a number of HIV positive refugees from sub-Saharan Africa, this hospitality is under threat due to negative public and political opinion. Epidemic conditions raise the social stakes attached to sexual exchanges, contagion becomes a major figure in social relationships and social production, and the fears of the contagious nature of those 'just off the plane' connect refugees to an equally deep-seated fear of racial miscegenation. Jacques Derrida's notion of unconditional hospitality is a dream of a democracy which would have a cosmopolitan form. This means that one cannot decide in advance which refugees one might choose to resettle. This paper will use Derrida's notion of unconditional hospitality to emphasise the fragility of HIV positive refugees' position, caught between becoming newly made New Zealand subjects while at the same time having that subjecthood threatened. For Derrida, both ethics and politics demand both an action and a need for a thoughtful response (a questioning without limit).     

An antifungal and plant growth promoting metabolite from a sterile dark ectotrophic fungus

A sterile dark ectotrophic fungus isolated from roots of an Australian native grass, Neurachne alopecuroidea produces compound 1 in liquid cultures. The structure of the metabolite was determined by spectroscopic and X-ray diffraction studies. The metabolite shows activity against phytopathogens and plant growth promoting activity, properties that are also expressed in vivo by the ectotrophic fungus.     

Effects of the laryngeal jet on nano- and microparticle transport and deposition in an approximate model of the upper tracheobronchial airways.

The extent to which laryngeal-induced flow features penetrate into the upper tracheobronchial (TB) airways and their related impact on particle transport and deposition are not well understood. The objective of this study was to evaluate the effects of including the laryngeal jet on the behavior and fate of inhaled aerosols in an approximate model of the upper TB region. The upper TB model was based on a simplified numerical reproduction of a replica cast geometry used in previous in vitro deposition experiments that extended to the sixth respiratory generation along some paths. Simulations with and without an approximate larynx were performed. Particle sizes ranging from 2.5 nm to 12 mum were considered using a well-tested Lagrangian tracking model. The model larynx was observed to significantly affect flow dynamics, including a laryngeal jet skewed toward the right wall of the trachea and a significant reverse flow in the left region of the trachea. Inclusion of the laryngeal model increased the tracheal deposition of nano- and micrometer particles by factors ranging from 2 to 10 and significantly reduced deposition in the first three bronchi of the model. Considering localized conditions, inclusion of the laryngeal approximation decreased deposition at the main carina and produced a maximum in local surface deposition density in the lobar-to-segmental bifurcations (G2-G3) for both 40-nm and 4-microm aerosols. These findings corroborate previous experiments and highlight the need to include a laryngeal representation in future computational and in vitro models of the TB region.