Interactions among morphotype,nutrition, and temperature impact fitness of an invasive fly

Invasive animals depend on finding a balanced nutritional intake to colonize, survive, and reproduce in new environments. This can be especially challenging during situations of fluctuating cold temperatures and food scarcity, but phenotypic plasticity may offer an adaptive advantage during these periods. We examined how lifespan, fecundity, pre‐oviposition periods, and body nutrient contents were affected by dietary protein and carbohydrate (P:C) ratios at variable low temperatures in two morphs (winter morphs WM and summer morphs SM) of an invasive fly, Drosophila suzukii. The experimental conditions simulated early spring after overwintering and autumn, crucial periods for survival. At lower temperatures, post‐overwintering WM lived longer on carbohydrate‐only diets and had higher fecundity on low‐protein diets, but there was no difference in lifespan or fecundity among diets for SM. As temperatures increased, low‐protein diets resulted in higher fecundity without compromising lifespan, while high‐protein diets reduced lifespan and fecundity for both WM and SM. Both SM and WM receiving high‐protein diets had lower sugar, lipid, and glycogen (but similar protein) body contents compared to flies receiving low‐protein and carbohydrate‐only diets. This suggests that flies spend energy excreting excess dietary protein, thereby affecting lifespan and fecundity. Despite having to recover from nutrient depletion after an overwintering period, WM exhibited longer lifespan and higher fecundity than SM in favorable diets and temperatures. WM exposed to favorable low‐protein diet had higher body sugar, lipid, and protein body contents than SM, which is possibly linked to better performance. Although protein is essential for oogenesis, WM and SM flies receiving low‐protein diets did not have shorter pre‐oviposition periods compared to flies on carbohydrate‐only diets. Finding adequate carbohydrate sources to compensate protein intake is essential for the successful persistence of D. suzukii WM and SM populations during suboptimal temperatures.     

Simultaneous clustering of gene expression data with clinical chemistry and pathological evaluations reveals phenotypic prototypes

Background  

Commonly employed clustering methods for analysis of gene expression data do not directly incorporate phenotypic data about the samples. Furthermore, clustering of samples with known phenotypes is typically performed in an informal fashion. The inability of clustering algorithms to incorporate biological data in the grouping process can limit proper interpretation of the data and its underlying biology.     

An exploratory study of cardiac function and oxygen uptake during cycle ergometry in overweight children

Objective: Obesity has been proposed to negatively impact cardiac function in overweight (OW) individuals. The relationship between diastolic dysfunction and oxygen uptake (V?o ₂) kinetics is equivocal. This exploratory investigation evaluated the relationship between resting left ventricular function and V?o ₂ kinetics during cycle ergometry in OW and non‐overweight (NO) children and adolescents. Research Methods and Procedures: Fourteen OW (>85 percentile for BMI for age and gender) children, 10 boys and 4 girls (age, 11.7 ± 1.9 years; body mass, 80.6 ± 45.5 kg) and 10 NO children (4 boys, 6 girls) volunteered to participate in the study (age, 12.5 ± 2.1 years; body mass, 45.8 ± 13.8 kg). Resting cardiovascular structure and function were assessed using spectral Doppler echocardiography. All subjects underwent two sub‐maximal exercise stages on a cycle ergometer (3 minutes unloaded and 5 minutes at 50 W, both at a cadence of 50 rpm). Respiratory data were measured on a breath‐by‐breath basis at both workloads and the mean response time (MRT) was calculated. Results: Analysis of the MRT data demonstrated that there were no significant differences between OW and NO (OW, 52.6 ± 11.7 seconds vs. NO, 45.6 ± 7.4 seconds). Significant correlations (p < 0.05) were obtained between MRT V?o ₂ and echocardiographic‐derived mitral valve inflow pressure half‐time (r = 0.55) and between MRT V?o ₂, and mitral valve inflow deceleration time (r = 0.55). Discussion: The evidence from this research suggests a possible link between left ventricular diastolic function at rest and oxygen uptake kinetics during sub‐maximal exercise in OW and NO children and adolescents.     

Escherichia coli “TatExpress” strains export several g/L human growth hormone to the periplasm by the Tat pathway

Escherichia coli is a heavily used platform for the production of biotherapeutic and other high-value proteins, and a favored strategy is to export the protein of interest to the periplasm to simplify downstream processing and facilitate disulfide bond formation. The Sec pathway is the standard means of transporting the target protein but it is unable to transport complex or rapidly folding proteins because the Sec system can only transport proteins in an unfolded state. The Tat system also operates to transport proteins to the periplasm, and it has significant potential as an alternative means of recombinant protein production because it transports fully folded proteins. Here, we have tested the Tat system's full potential for the production of biotherapeutics for the first time using fed-batch fermentation. We expressed human growth hormone (hGH) with a Tat signal peptide in E. coli W3110 “TatExpress” strains that contain elevated levels of the Tat apparatus. This construct contained four amino acids from TorA at the hGH N-terminus as well as the initiation methionine from hGH, which is removed in vivo. We show that the protein is efficiently exported to the periplasm during extended fed-batch fermentation, to the extent that it is by far the most abundant protein in the periplasm. The protein was shown to be homogeneous, disulfide bonded, and active. The bioassay showed that the yields of purified periplasmic hGH are 5.4 g/L culture whereas an enzyme-linked immunosorbent assay gave a figure of 2.39 g/L. Separate analysis of a TorA signal peptide linked to hGH construct lacking any additional amino acids likewise showed efficient export to the periplasm, although yields were approximately two-fold lower.     

Breeding populations of Little Ringed Plover Charadrius dubius and Ringed Plover Charadrius hiaticula in the United Kingdom in 2007

Capsule: The 2007 national survey of the UK breeding population of Little Ringed Plovers shows a further spread into Scotland and Wales since the previous survey in 1984. In contrast, there has been a significant decrease in the Ringed Plover breeding population.

Aims: To provide new breeding population estimates in the UK and Great Britain for Little Ringed Plover Charadrius dubius and Ringed Plover Charadrius hiaticula in 2007 and investigate changes in breeding distribution and habitat use since 1984.

Methods: Breeding population estimates were made by combining counts of pairs from ‘key sites’ (2?×?2?km tetrads known to be occupied in/since 1984) and estimates of the numbers of pairs away from these sites based on stratified sampling. Survey periods for Little Ringed Plover: 15 April to 15 July, three visits; Ringed Plover: 15 April to 30 June, two visits.

Results: Population estimates, for 2007, of 1239 (95% confidence intervals: 1175–1311) pairs of Little Ringed Plover and 5291 (5106–5478) pairs of Ringed Plovers were calculated for Great Britain, with 5438 (5257–5622) pairs of Ringed Plover estimated in the UK. Counts of Ringed Plover at inland and coastal sites, covered in both 1984 and 2007, decreased by 83% and 53%, respectively. The Little Ringed Plover population has expanded in range northward and westward since 1984. Main habitats used in 2007 by Little Ringed Plover were inland gravel and sand (25.9%) and river shingle (17.8%); and, for Ringed Plover, coastal shingle and sand (38.5% and 13.7%, respectively) and machair plus associated habitats (23.8%) in the Outer Hebrides.

Conclusions: Between 1984 and 2007, the Little Ringed Plover breeding population in the UK increased considerably, expanding northward and westward, with increased use of river shingle habitats. During the same period Ringed Plover breeding numbers in the UK declined considerably in both coast and inland habitats, likely to be due to human disturbance and habitat change, respectively.     

Variation in cranial morphology of bottlenose dolphins (genus Tursiops) off South Africa

Taxonomy plays an important role in conservation biology. Despite the variety of methods used to differentiate units, some groups, such as Delphinidae within the Cetacea have proven difficult to untangle. This study aimed to shed light on morphological variation of the genus Tursiops in South African waters using geometric morphometrics and to distinguish morphological groups and variation in these groups. A total of 241 crania of Tursiops spp. were analyzed using a suite of 2‐dimensional landmarks defined on photographs of the specimens. Results revealed two distinct morphological groups, with the smaller cluster comprised mainly of specimens from the cold temperate region off the west coast and the larger cluster comprised of specimens mainly from the warm temperate and subtropical regions off the south and east coast, respectively. We suggest that these groups correspond to different species of Tursiops, but this result requires further support. These groups were treated as separate entities and sexual dimorphism and geographic variation were assessed within each group. While sexual dimorphism and geographic variation were not significant within Cluster D1 and V1, they were significant within Clusters D2 and V2. The few Cluster 1 specimens found in the warm temperate and subtropical regions, relative to the number of Cluster 2 specimens, could be an indication of an offshore distribution for this group in these regions. Alternatively, the smaller cluster may also be indicative of a potentially small population size.     

Extensive public health initiatives drive the elimination of Aedes aegypti (Diptera,Culicidae) from a town in regional Queensland: A case study from Gin Gin,Australia

Aedes aegypti is the primary vector of exotic arboviruses (dengue, chikungunya and Zika) in Australia. Once established across much of Australia, this mosquito species remains prevalent in central and northern Queensland. In 2011, Ae. aegypti was re-discovered in the town of Gin Gin, Queensland, by health authorities during routine larval surveillance. This town is situated on a major highway that provides a distribution pathway into the highly vulnerable and populous region of the state where the species was once common. Following the detection, larval habitat and adult control activities were conducted as a public health intervention to eliminate the Ae. aegypti population and reduce the risk of exotic disease transmission. Importantly, genetic analysis revealed a homogenous cluster and small effective population vulnerable to an elimination strategy. By 2015, adult surveillance revealed the population had expanded throughout the centre of the town. In response, a collaboration between research agencies and local stakeholders activated a second control program in 2016 that included extensive community engagement, enhanced entomologic surveillance and vector control activities including the targeting of key containers, such as unsealed rainwater tanks. Here we describe a model of the public health intervention which successfully reduced the Ae. aegypti population below detection thresholds, using source reduction, insecticides and novel, intensive genetic surveillance methods. This outcome has important implications for future elimination work in small towns in regions sub-optimal for Ae. aegypti presence and reinforces the longstanding benefits of a partnership model for public health-based interventions for invasive urban mosquito species.