Quantifying Fish Assemblages in Large,Offshore Marine Protected Areas: An Australian Case Study

As the number of marine protected areas (MPAs) increases globally, so does the need to assess if MPAs are meeting their management goals. Integral to this assessment is usually a long-term biological monitoring program, which can be difficult to develop for large and remote areas that have little available fine-scale habitat and biological data. This is the situation for many MPAs within the newly declared Australian Commonwealth Marine Reserve (CMR) network which covers approximately 3.1 million km² of continental shelf, slope, and abyssal habitat, much of which is remote and difficult to access. A detailed inventory of the species, types of assemblages present and their spatial distribution within individual MPAs is required prior to developing monitoring programs to measure the impact of management strategies. Here we use a spatially-balanced survey design and non-extractive baited video observations to quantitatively document the fish assemblages within the continental shelf area (a multiple use zone, IUCN VI) of the Flinders Marine Reserve, within the Southeast marine region. We identified distinct demersal fish assemblages, quantified assemblage relationships with environmental gradients (primarily depth and habitat type), and described their spatial distribution across a variety of reef and sediment habitats. Baited videos recorded a range of species from multiple trophic levels, including species of commercial and recreational interest. The majority of species, whilst found commonly along the southern or south-eastern coasts of Australia, are endemic to Australia, highlighting the global significance of this region. Species richness was greater on habitats containing some reef and declined with increasing depth. The trophic breath of species in assemblages was also greater in shallow waters. We discuss the utility of our approach for establishing inventories when little prior knowledge is available and how such an approach may inform future monitoring efforts within the CMR network.     

Propranolol uptake by dog lung: effect of pulmonary artery occlusion and shock lung

First-pass lung uptake of propranolol in catheterized ambulant dogs was measured by comparison the difference between the ratios of [14C]propranolol to indocyanine green (ICG) before and after a single passage through the pulmonary circulation. Uptake was 56 +/- 5, 53 +/- 8, and 61 +/- 10% (mean +/- SD) when 0.02, 0.2, and 2.0 mg of propranolol were injected, respectively. There was a negative though unimportant correlation between percent uptake and cardiac output. Analysis of paired propranolol and ICG outflow curves confirmed the lack of saturation with increasing dose and suggested the involvement of simple diffusion. In four dogs uptake fell from 4.76 +/- 6.8 to 40.4 +/- 8.2% (0.05 greater than P greater than 0.025) during partial occlusion of the pulmonary circulation by a Swan-Ganz catheter balloon and rose again to 51.2 +/- 6.4% after relief of the occlusion. Propranolol uptake, measured serially in five dogs with indwelling catheters, was initially 55% but fell linearly to 30% over 2 wk (r = -0.59, P less than 0.001), and necropsy showed pathological features of shock lung. A similar study performed on three dogs within 4 days of catheterization showed no change in uptake of the drug. Propranolol uptake appears to reflect both quantitative and qualitative changes in the pulmonary endothelium. This method may therefore be valuable in studying the pulmonary endothelium in health and disease.     

Rapid degradation of Bim by the ubiquitin-proteasome pathway mediates short-term ischemic tolerance in cultured neurons

A previous exposure to a non-harmful ischemic insult (preconditioning) protects the brain against subsequent harmful ischemia (ischemic tolerance). In contrast to delayed gene-mediated ischemic tolerance, little is known about the molecular mechanisms that regulate rapid ischemic tolerance, which occurs within 1 h following preconditioning. Here we have investigated the degradation of the pro-apoptotic Bcl-2 family member Bim as a mechanism of rapid ischemic tolerance. Bim protein levels were reduced 1 h following preconditioning and occurred concurrent with an increase in Bim ubiquitination. Ubiquitinated proteins are degraded by the proteasome, and inhibition of the proteasome with MG132 (a proteasome inhibitor) prevented Bim degradation and blocked rapid ischemic tolerance. Inhibition of p42/p44 mitogen-activated protein kinase activation by U0126 reduced Bim ubiquitination and Bim degradation and blocked rapid ischemic tolerance. Finally, inhibition of Bim expression using antisense oligonucleotides also reduced cell death following ischemic challenge. Our results suggest that following preconditioning ischemia, Bim is rapidly degraded by the ubiquitin-proteasome system, resulting in rapid ischemic tolerance. This suggests that the rapid degradation of cell death-promoting proteins by the ubiquitin-proteasome pathway may represent a novel therapeutic strategy to reduce cell damage following neuropathological insults, e.g. stroke.     

A quantitative study of the morphological development and bacterial colonisation of the gut of the tammar wallaby Macropus eugenii eugenii and brushtail possum Trichosurus vulpecula during in-pouch development

We compared the rates of change of various morphological parameters of the stomach, small intestine, caecum and colon of tammar wallabies and brushtail possums with body mass during in-pouch development. These were correlated with changes in the numbers of bacterial species in the various gut segments. In the pouch-young of both species, the wet tissue masses of all gut segments increased with body mass in a positively allometric manner (i.e. with a body mass exponent > 1), suggesting that the mass of each component was disproportionately low at birth, but increased disproportionately rapidly postnatally. However, the lengths of the wallaby stomach and small intestine scaled isometrically with respect to body mass (i.e. with a body mass exponent around 0.33), which may indicate that the shape of these components changes to the adult form during early neonatal development. Conversely, the length of the caecum and colon of both wallabies and possums scaled in a positively allometric manner with respect to body mass, showing area to volume compensation. This may indicate a more general pattern of disproportionately rapid postnatal enlargement in areas that are distal to the principal sites of neonatal digestion (i.e. the stomach). The numbers of bacterial species present in the various gastrointestinal segments of both species were low in animals aged 100 days or less but there was a significant increase in microbial diversity in the caecum of brushtail possums aged over 100 days. The possum caecum also showed the greatest rate of increase in wet tissue mass relative to body mass. It is postulated that caecal development may act as a nidus for establishment of communities of commensal microflora in the developing marsupial.     

The cytoplasmic tail of the severe acute respiratory syndrome coronavirus spike protein contains a novel endoplasmic reticulum retrieval signal that binds COPI and promotes interaction with membrane protein

Like other coronaviruses, severe acute respiratory syndrome coronavirus (SARS CoV) assembles at and buds into the lumen of the endoplasmic reticulum (ER)-Golgi intermediate compartment (ERGIC). Accumulation of the viral envelope proteins at this compartment is a prerequisite for virus assembly. Previously, we reported the identification of a dibasic motif (KxHxx) in the cytoplasmic tail of the SARS CoV spike (S) protein that was similar to a canonical dilysine ER retrieval signal. Here we demonstrate that this motif is a novel and functional ER retrieval signal which reduced the rate of traffic of the full-length S protein through the Golgi complex. The KxHxx motif also partially retained two different reporter proteins in the ERGIC region and reduced their rates of trafficking, although the motif was less potent than the canonical dilysine signal. The dibasic motif bound the coatomer complex I (COPI) in an in vitro binding assay, suggesting that ER retrieval may contribute to the accumulation of SARS CoV S protein near the virus assembly site for interaction with other viral structural proteins. In support of this, we found that the dibasic motif on the SARS S protein was required for its localization to the ERGIC/Golgi region when coexpressed with SARS membrane (M) protein. Thus, the cycling of SARS S through the ER-Golgi system may be required for its incorporation into assembling virions in the ERGIC.     

Spatiotemporal mapping of ex vivo motility in the caecum of the rabbit

We used high definition radial, strain rate and intensity spatiotemporal mapping to quantify contractile movements of the body and associated structures of the rabbit caecum when the terminal ileum was being perfused with saline at a constant rate. This perfusion caused gradual distension of the caecum as a result of relative restriction of outflow from the ampulla caecalis. The body of the caecum exhibited two patterns of motility that appeared autonomous, i.e. occurred independently of any contractile activity at the inlet or outlet. Firstly, the pattern that we termed ladder activity consisted of an orderly sequential contraction of bundles of axially oriented circular muscle between the spiral turns of longitudinal muscle and proceeded either from base to tip or from tip to base at a similar frequency and velocity. Secondly, less-localised, rapidly propagating synchronous contractions of both circular and longitudinal muscle, which were more common when the caecum was distended, that were termed mass peristalsis. Movements of the ileum and sacculus rotundus occurred at the same frequency and were broadly coordinated. Distension of the distal sacculus occurred synchronously with contraction of the ileum and did not propagate in an orderly manner across the structure, i.e. was instantaneous. This pattern was consistent with hydrostatic distension. Contractions propagated through the ampulla caecalis in either an orad or an aborad direction at a similar frequency to, and broadly correlated with, those in the ileum. The frequencies of distension of the sacculus and of contraction in the ileum and ampulla were momentarily augmented during mass peristalsis. The authors conclude that there was some coordination between the contractile activity of the terminal ileum and the caecal ampulla during periods of ongoing inflow from the ileum and between these structures and the caecum during mass peristalsis.     

Biocontrol exerts natural selection against fecundity traits in Cytisus scoparius (L.)

Evolutionary Ecology - Biological invasions represent a useful experimental system with which evolutionary processes can be investigated in a contemporary timespan. One process that can be studied...