Dispersal and social organization of the northern hairy-nosed wombat Lasiorhinus krefftii

Burrows of the northern hairy-nosed wombat were arranged in loose clusters, each of which was used in common by a group of up to 10 wombats. However, individual wombats rarely used the same burrows on the same days and feeding ranges tended to be separate within each sex. The incidence of breeding dispersal among females was quite high (at least 50%); dispersal distances ranged up to almost the full extent of the population's range. Dispersal by adult males was rare, and no juvenile males were observed to disperse.     

Hybridization in the Cetacea: widespread occurrence and associated morphological,behavioral, and ecological factors

Hybridization has been documented in a many different pairs of cetacean species both in captivity and in the wild. The widespread occurrence of hybridization indicates that postmating barriers to interbreeding are incomplete within the order Cetacea, and therefore raises questions about how species integrity is maintained in the face of interspecific (and often intergeneric) gene flow. We examined hybridization across the order Cetacea (oceanic species included: N = 78; species with 44 chromosomes included: N = 52) to test for associations between the occurrence of hybridization and similarity across 13 ecological, morphological and behavioral traits in hybridizing vs. non‐hybridizing species pairs. We found that species pairs that share a greater number of traits had a higher propensity to hybridize than pairs of species that did not. This trend was driven by behavioral and morphological traits such as vocalization frequency and body size. Together our findings suggest the importance of divergent selection on morphological and behavioral traits within sympatric species in constraining opportunities for hybridization and preventing the collapse of parental species.     

Relative larval loss among females during dispersal of Lake Sturgeon (<Emphasis Type="Italic">Acipenser fulvescens</Emphasis>)

Mortality that occurs during larval dispersal as a consequence of environmental, maternal, and genetic effects and their interactions can affect annual recruitment in fish populations. We studied larval lake sturgeon (Acipenser fulvescens) drift for two consecutive nights to examine whether larvae from different females exposed to the same environmental conditions during dispersal differed in relative levels of mortality. We estimated proportional contributions of females to larval collections and relative larval loss among females as larvae dispersed downstream between two sampling sites based on genetically determined parentage. Larval collections were composed of unequal proportions of offspring from different females that spawned at upstream and downstream locations (~0.8 km apart). Hourly dispersal patterns of larvae produced from females spawning at both locations were similar, with the largest number of larvae observed during 22:00–23:00 h. Estimated relative larval loss did not differ significantly among females as larvae were sampled at two sites approximately 0.15 and 1.5 km from the last section downstream of spawning locations. High inter- and intra-female variation in larval contributions and relative larval loss between nights may be a common feature of lake sturgeon and other migratory fish species, and likely is a source of inter-annual and intra-annual variation in fish recruitment.     

Species vulnerability to climate change: impacts on spatial conservation priorities and species representation

Climate change may shrink and/or shift plant species ranges thereby increasing their vulnerability and requiring targeted conservation to facilitate adaptation. We quantified the vulnerability to climate change of plant species based on exposure, sensitivity and adaptive capacity and assessed the effects of including these components in complementarity‐based spatial conservation prioritisation. We modelled the vulnerability of 584 native plant species under three climate change scenarios in an 11.9 million hectare fragmented agricultural region in southern Australia. We represented exposure as species' geographical range under each climate change scenario as quantified using species distribution models. We calculated sensitivity as a function of the impact of climate change on species' geographical ranges. Using a dispersal kernel, we quantified adaptive capacity as species' ability to migrate to new geographical ranges under each climate change scenario. Using Zonation, we assessed the impact of individual components of vulnerability (exposure, sensitivity and adaptive capacity) on spatial conservation priorities and levels of species representation in priority areas under each climate change scenario. The full vulnerability framework proved an effective basis for identifying spatial conservation priorities under climate change. Including different dimensions of vulnerability had significant implications for spatial conservation priorities. Incorporating adaptive capacity increased the level of representation of most species. However, prioritising sensitive species reduced the representation of other species. We conclude that whilst taking an integrated approach to mitigating species vulnerability to climate change can ensure sensitive species are well‐represented in a conservation network, this can come at the cost of reduced representation of other species. Conservation planning decisions aimed at reducing species vulnerability to climate change need to be made in full cognisance of the sensitivity of spatial conservation priorities to individual components of vulnerability, and the trade‐offs associated with focussing on sensitive species.     

Neuropeptide Y Gene Polymorphisms Confer Risk of Early-Onset Atherosclerosis

Neuropeptide Y (NPY) is a strong candidate gene for coronary artery disease (CAD). We have previously identified genetic linkage to familial CAD in the genomic region of NPY. We performed follow-up genetic, biostatistical, and functional analysis of NPY in early-onset CAD. In familial CAD (GENECARD, N=420 families), we found increased microsatellite linkage to chromosome 7p14 (OSA LOD=4.2, p=0.004) in 97 earliest age-of-onset families. Tagged NPY SNPs demonstrated linkage to CAD of a 6-SNP block (LOD=1.58–2.72), family-based association of this block with CAD (p=0.02), and stronger linkage to CAD in the earliest age-of-onset families. Association of this 6-SNP block with CAD was validated in: (a) 556 non-familial early-onset CAD cases and 256 controls (OR 1.46–1.65, p=0.01–0.05), showing stronger association in youngest cases (OR 1.84–2.20, p=0.0004–0.09); and (b) GENECARD probands versus non-familial controls (OR 1.79–2.06, p=0.003–0.02). A promoter SNP (rs16147) within this 6-SNP block was associated with higher plasma NPY levels (p=0.04). To assess a causal role of NPY in atherosclerosis, we applied the NPY1-receptor–antagonist BIBP-3226 adventitially to endothelium-denuded carotid arteries of apolipoprotein E-deficient mice; treatment reduced atherosclerotic neointimal area by 50% (p=0.03). Thus, NPY variants associate with atherosclerosis in two independent datasets (with strong age-of-onset effects) and show allele-specific expression with NPY levels, while NPY receptor antagonism reduces atherosclerosis in mice. We conclude that NPY contributes to atherosclerosis pathogenesis.     

Parasite and mammalian GPI biosynthetic pathways can be distinguished using synthetic substrate analogues.

Glycosylphosphatidylinositol (GPI) structures are attached to many cell surface glycoproteins in lower and higher eukaryotes. GPI structures are particularly abundant in trypanosomatid parasites where they can be found attached to complex phosphosaccharides, as well as to glycoproteins, and as mature surface glycolipids. The high density of GPI structures at all life-cycle stages of African trypanosomes and Leishmania suggests that the GPI biosynthetic pathway might be a reasonable target for the development of anti-parasite drugs. In this paper we show that synthetic analogues of early GPI intermediates having the 2-hydroxyl group of the D-myo-inositol residue methylated are recognized and mannosylated by the GPI biosynthetic pathways of Trypanosoma brucei and Leishmania major but not by that of human (HeLa) cells. These findings suggest that the discovery and development of specific inhibitors of parasite GPI biosynthesis are attainable goals. Moreover, they demonstrate that inositol acylation is required for mannosylation in the HeLa cell GPI biosynthetic pathway, whereas it is required for ethanolamine phosphate addition in the T.brucei GPI biosynthetic pathway.     

Potent vasoactive properties of endothelin 1 in human skin.

The effect of the endothelial cell-derived peptide endothelin 1 was investigated in human skin. Intradermal injection of endothelin 1 (1-100 pmol) caused a dose-dependent area of pallor that was associated with a significant reduction in basal skin blood flow, measured by laser-Doppler blood flowmeter (with 1 pmol endothelin, P = 0.012, analysis of variance). The coadministration of endothelin 1 (1-100 pmol) with the neuropeptide vasodilator calcitonin gene-related peptide (CGRP) inhibited the vasodilator response to CGRP (10 pmol) by up to 82.7 +/- 9.2% (with 100 pmol endothelin, P less than 0.001). The response of the prostanoid vasodilator prostaglandin E2 (10 pmol) was inhibited by endothelin in a similar manner. In addition to the vasoconstrictor effects, endothelin 1 produced a dose-dependent flare that surrounded the area of pallor, and this was associated with a significant increase in blood flow (P less than 0.05) within the flare area. The H1 antagonist terfenadine (120 mg po) significantly reduced the flare area associated with endothelin 1: flare 5 min after intradermal endothelin (10 pmol, placebo treated), 668 +/- 405 mm2; terfenadine treated, 201 +/- 257 mm2 (P less than 0.05). The flare was also significantly attenuated when endothelin (10 pmol) was injected into local anesthetic-treated skin. Thus intradermal injection of endothelin in humans causes long-lasting vasoconstriction at the site of injection and a surrounding flare. Results suggest that the flare component is partially histamine dependent and the result of an axon reflex. This study demonstrates the potent activity of endothelin in human skin. It is possible that endothelin could be relevant to the local response of skin to injury.     

Synthesis of some second-generation substrate analogues of early intermediates in the biosynthetic pathway of glycosylphosphatidylinositol membrane anchors

1-D-6-O-(2-Amino-2-deoxy-alpha-D-glucopyranosyl)-2-O-octyl-myo-inositol 1-(1,2-di-O-hexadecanoyl-sn-glycerol 3-phosphate) (23) and the corresponding 2-O-hexadecyl-D-myo-inositol compound 24 have been prepared as substrate analogues of an early intermediate in the biosynthetic pathway of glycosylphosphatidylinositol (GPI) membrane anchors. 1-D-6-O-(2-Amino-2-deoxy-alpha-D-glucopyranosyl)-myo-inositol 1-(1,2-di-O-octyl-sn-glycerol 3-phosphate) has also been prepared as a substrate analogue. Biological evaluation of the analogues 23 and 24 revealed that they are neither substrates nor inhibitors of GPI biosynthetic enzymes in the human (HeLa) cell-free system but are potent inhibitors at different stages of GPI biosynthesis in the Trypanosoma brucei cell-free system.