Exercise training in heart failure

Chronic heart failure (CHF) is a common condition with a poor prognosis. It is associated with poor exercise tolerance and debilitating symptoms. These symptoms appear to be associated with pathophysiological changes that occur systemically in the patient with CHF. Exercise training in carefully selected patients has been shown to be safe and to improve exercise capacity. Many of the pathophysiological abnormalities of CHF are improved by training. Some studies have suggested a possible improvement in morbidity and mortality with training. This review analyzes the controlled clinical trials of exercise training in CHF published to date.     

Human demography and reserve size predict wildlife extinction in West Africa.

Species-area models have become the primary tool used to predict baseline extinction rates for species in isolated habitats, and have influenced conservation and land-use planning worldwide. In particular, these models have been used to predict extinction rates following the loss or fragmentation of natural habitats in the absence of direct human influence on species persistence. Thus, where direct human influences, such as hunting, put added pressure on species in remnant habitat patches, we should expect to observe extinction rates higher than those predicted by simple species-area models. Here, we show that extinction rates for 41 species of large mammals in six nature reserves in West Africa are 14-307 times higher than those predicted by models based on reserve size alone. Human population and reserve size accounted for 98% of the observed variation in extinction rates between reserves. Extinction occurred at higher rates than predicted by species-area models for carnivores, primates and ungulates, and at the highest rates overall near reserve borders. Our results indicate that, where the harvest of wildlife is common, conservation plans should focus on increasing the size of reserves and reducing the rate of hunting.     

Technical comment on Boersma et al. (2016) Temperature driven changes in the diet preference of omnivorous copepods: no more meat when it's hot? Ecology Letters, 19, 45–53

A recent study concluded that omnivorous plankton will shift from predatory to herbivorous feeding with climate warming, as consumers require increased carbon:phosphorous in their food. Although this is an appealing hypothesis, we suggest the conclusion is unfounded, based on the data presented, which seem in places questionable and poorly interpreted.     

A feature selection approach for identification of signature genes from SAGE data

Background  

One goal of gene expression profiling is to identify signature genes that robustly distinguish different types or grades of tumors. Several tumor classifiers based on expression profiling have been proposed using microarray technique. Due to important differences in the probabilistic models of microarray and SAGE technologies, it is important to develop suitable techniques to select specific genes from SAGE measurements.     

Topological studies on the enzymes catalyzing the biosynthesis of Glc-P- dolichol and the triglucosyl cap of Glc3Man9GlcNAc2-P-P-dolichol in microsomal vesicles from pig brain: use of the processing glucosidases I/II as latency markers

In the current model for Glc3Man9GlcNAc2-P-P-Dol assembly, Man5GlcNAc2- P-P-Dol, Man-P-Dol, and Glc-P-Dol are synthesized on the cytoplasmic face of the ER and diffuse transversely to the lumenal leaflet where the synthesis of the lipid-bound precursor oligosaccharide is completed. To establish the topological sites of Glc-P-Dol synthesis and the lipid-mediated glucosyltransfer reactions involved in Glc3Man9GlcNAc2-P-P-Dol synthesis in ER vesicles from pig brain, the trypsin-sensitivity of Glc-P-Dol synthase activity and the Glc-P- Dol:Glc0-2Man9GlcNAc2-P-P-Dol glucosyltransferases (GlcTases) was examined in sealed microsomal vesicles. Since ER vesicles from brain do not contain glucose 6-phosphate (Glc 6-P) phosphatase activity, the latency of the lumenally oriented, processing glucosidase I/II activities was used to assess the intactness of the vesicle preparations. Comparative enzymatic studies with sealed ER vesicles from brain and kidney, a tissue that contains Glc 6-P phosphatase, demonstrate the reliability of using the processing glucosidase activities as latency markers for topological studies with microsomal vesicles from non-gluconeogenic tissues lacking Glc 6-P phosphatase. The results obtained from the trypsin-sensitivity assays with sealed microsomal vesicles from brain are consistent with a topological model in which Glc-P-Dol is synthesized on the cytoplasmic face of the ER, and subsequently utilized by the three Glc-P-Dol-mediated GlcTases after "flip-flopping" to the lumenal monolayer.      

Quantifying past and present connectivity illuminates a rapidly changing landscape for the African elephant

There is widespread concern about impacts of land‐use change on connectivity among animal and plant populations, but those impacts are difficult to quantify. Moreover, lack of knowledge regarding ecosystems before fragmentation may obscure appropriate conservation targets. We use occurrence and population genetic data to contrast connectivity for a long‐lived mega‐herbivore over historical and contemporary time frames. We test whether (i) historical gene flow is predicted by persistent landscape features rather than human settlement, (ii) contemporary connectivity is most affected by human settlement and (iii) recent gene flow estimates show the effects of both factors. We used 16 microsatellite loci to estimate historical and recent gene flow among African elephant (Loxodonta africana) populations in seven protected areas in Tanzania, East Africa. We used historical gene flow (F_ST and G'_ST) to test and optimize models of historical landscape resistance to movement. We inferred contemporary landscape resistance from elephant resource selection, assessed via walking surveys across ~15 400 km² of protected and unprotected lands. We used assignment‐based recent gene flow estimates to optimize and test the contemporary resistance model, and to test a combined historical and contemporary model. We detected striking changes in connectivity. Historical connectivity among elephant populations was strongly influenced by slope but not human settlement, whereas contemporary connectivity was influenced most by human settlement. Recent gene flow was strongly influenced by slope but was also correlated with contemporary resistance. Inferences across multiple timescales can better inform conservation efforts on large and complex landscapes, while mitigating the fundamental problem of shifting baselines in conservation.     

Scent marking in a territorial African antelope: I. The maintenance of borders between male oribi

Scent marking is ubiquitous among the dwarf antelope and gazelles of Africa, but its function has been the subject of debate. This study examined preorbital gland scent marking in the oribi, Ourebia ourebi, a territorial African antelope. Several hypotheses for the function of scent marking by territorial antelope were tested with observational data. Of these, the hypotheses that scent marking is driven by intrasexual competition between neighbouring males, and that marks serve as an honest advertisement of a male's ability to defend his territory from rivals, were supported best. Thirty-three territorial male oribi on 23 territories marked most at borders shared with other territorial males, and territorial males marked more often at borders shared with multimale groups than at borders shared with a single male. This suggests that males perceived neighbouring male groups as a greater threat to territory ownership than neighbouring males that defended their territories without the aid of adult subordinates. Marking rate was unrelated to territory size or the number of females on adjacent territories, but males with many male neighbours marked at higher rates than those with fewer male neighbours. These results suggest that the presence of male neighbours has a greater effect on the scent marking behaviour of territorial antelope than has been considered previously. Copyright 1999 The Association for the Study of Animal Behaviour.