Gene expression and the evolution of phenotypic diversity in social wasps

Background  

Organisms are capable of developing different phenotypes by altering the genes they express. This phenotypic plasticity provides a means for species to respond effectively to environmental conditions. One of the most dramatic examples of phenotypic plasticity occurs in the highly social hymenopteran insects (ants, social bees, and social wasps), where distinct castes and sexes all arise from the same genes. To elucidate how variation in patterns of gene expression affects phenotypic variation, we conducted a study to simultaneously address the influence of developmental stage, sex, and caste on patterns of gene expression in Vespula wasps. Furthermore, we compared the patterns found in this species to those found in other taxa in order to investigate how variation in gene expression leads to phenotypic evolution.     

Quantifying Climatological Ranges and Anomalies for Pacific Coral Reef Ecosystems

Coral reef ecosystems are exposed to a range of environmental forcings that vary on daily to decadal time scales and across spatial scales spanning from reefs to archipelagos. Environmental variability is a major determinant of reef ecosystem structure and function, including coral reef extent and growth rates, and the abundance, diversity, and morphology of reef organisms. Proper characterization of environmental forcings on coral reef ecosystems is critical if we are to understand the dynamics and implications of abiotic–biotic interactions on reef ecosystems. This study combines high-resolution bathymetric information with remotely sensed sea surface temperature, chlorophyll-a and irradiance data, and modeled wave data to quantify environmental forcings on coral reefs. We present a methodological approach to develop spatially constrained, island- and atoll-scale metrics that quantify climatological range limits and anomalous environmental forcings across U.S. Pacific coral reef ecosystems. Our results indicate considerable spatial heterogeneity in climatological ranges and anomalies across 41 islands and atolls, with emergent spatial patterns specific to each environmental forcing. For example, wave energy was greatest at northern latitudes and generally decreased with latitude. In contrast, chlorophyll-a was greatest at reef ecosystems proximate to the equator and northern-most locations, showing little synchrony with latitude. In addition, we find that the reef ecosystems with the highest chlorophyll-a concentrations; Jarvis, Howland, Baker, Palmyra and Kingman are each uninhabited and are characterized by high hard coral cover and large numbers of predatory fishes. Finally, we find that scaling environmental data to the spatial footprint of individual islands and atolls is more likely to capture local environmental forcings, as chlorophyll-a concentrations decreased at relatively short distances (>7 km) from 85% of our study locations. These metrics will help identify reef ecosystems most exposed to environmental stress as well as systems that may be more resistant or resilient to future climate change.     

Seasonal cycle of planktonic communities at Inhaca Island, southern Mozambique

Monthly plankton sampling was carried out at three stationson the west coast of Inhaca Island, southern Mozambique, fromAugust 1994 to August 1995. Sampling included water mass physicalparameters, nutrients, chlorophyll and zooplankton with netsof 125 and 330 µm pore aperture. Nutrient concentrationhas shown maxima during the summer months, where rain providesthe maximum outflow of rivers discharging into Maputo Bay. Followingthe nutrient peak, chlorophyll a has shown maxima around themonth of April, with another minor peak in September, when temperaturebegins to increase. Zooplankton densities followed closely thephytoplankton peaks, especially small herbivorous taxa and larvalstages, such as gastropod and bivalve larvae.     

The importance of species range attributes and reserve configuration for the conservation of angiosperm diversity in Western Australia

In order to better understand the relationship between reserve design and the species represented by such designs, we examined the effectiveness of the Western Australian reserve system for conserving angiosperm diversity, and examined the characteristics of those species conserved. We overlayed species distribution data for 14 plant lineages with the distribution of the reserve system (8.5% of the State’s area) and identified the species that remained unprotected. We found that, depending upon the method employed, between 174 (5.7%) and 570 (18.7%) of species were not included within the reserve system. Two main unprotected regions were identified, one of which was also a centre of high diversity. Geographical range sizes of unprotected species were six times smaller than those species that were protected, while species richness of small-ranged endemic species coincided with general patterns of species richness. At the level of Western Australia’s bioregions we found that conservation effectiveness was most dependent on characteristics of the reserve system rather than characteristics (size and positioning) of species ranges. At this scale, the most effective way to conserve more species in Western Australia would be to conserve more land, while conservation would be most successful in a uniformly dispersed reserve system. Our results highlight the fact that reserve systems may take on two design approaches based on scale––at continental scales, reserves should be clustered around the hotspots of endemic species, while within regions, an evenly distributed reserve system will most adequately sample species.     

Intravenous acetylcysteine in paracetamol induced fulminant hepatic failure: a prospective controlled trial.

OBJECTIVE--To see whether intravenous acetylcysteine would improve outcome in patients with fulminant hepatic failure after paracetamol overdose. DESIGN--A prospective randomised controlled study. SETTING--The Institute of Liver Studies, King''s College Hospital, London. PATIENTS--50 consecutive patients (21 male) aged 16-60 with fulminant hepatic failure after paracetamol overdose who had not previously received acetylcysteine. INTERVENTIONS--Conventional intensive liver care plus either acetylcysteine (25 patients) in the same dose regimen as used early after a paracetamol overdose, except that the infusion was continued until recovery from encephalopathy or death, or an equivalent volume of 5% dextrose (25 patients). MAIN OUTCOME MEASURES--Survival; incidence of cerebral oedema, renal failure, and hypotension requiring inotropic support; liver function as assessed by prolongation of the prothrombin time; and degree of encephalopathy. RESULTS--The rate of survival was significantly higher in the acetylcysteine treated group than in the controls (48% (12/25 patients) v 20% (5/25); p = 0.037, 95% confidence interval for difference in proportions surviving 3% to 53%). Acetylcysteine treated patients had a lower incidence of cerebral oedema (40% (10/25) v 68% (17/25); p = 0.047, 95% confidence interval for difference in incidence 2% to 54%), and fewer developed hypotension requiring inotropic support (48% (12/25) v 80% (20/25); p = 0.018, 95% confidence interval 7% to 57%). Rates of deterioration and recovery of liver function, however, were similar in the two groups. No adverse reactions to acetylcysteine were seen. CONCLUSIONS--Acetylcysteine is safe and effective in fulminant hepatic failure after paracetamol overdose.