Wolbachia Stimulates Immune Gene Expression and Inhibits Plasmodium Development in Anopheles gambiae

The over-replicating wMelPop strain of the endosymbiont Wolbachia pipientis has recently been shown to be capable of inducing immune upregulation and inhibition of pathogen transmission in Aedes aegypti mosquitoes. In order to examine whether comparable effects would be seen in the malaria vector Anopheles gambiae, transient somatic infections of wMelPop were created by intrathoracic inoculation. Upregulation of six selected immune genes was observed compared to controls, at least two of which (LRIM1 and TEP1) influence the development of malaria parasites. A stably infected An. gambiae cell line also showed increased expression of malaria-related immune genes. Highly significant reductions in Plasmodium infection intensity were observed in the wMelPop-infected cohort, and using gene knockdown, evidence for the role of TEP1 in this phenotype was obtained. Comparing the levels of upregulation in somatic and stably inherited wMelPop infections in Ae. aegypti revealed that levels of upregulation were lower in the somatic infections than in the stably transinfected line; inhibition of development of Brugia filarial nematodes was nevertheless observed in the somatic wMelPop infected females. Thus we consider that the effects observed in An. gambiae are also likely to be more pronounced if stably inherited wMelPop transinfections can be created, and that somatic infections of Wolbachia provide a useful model for examining effects on pathogen development or dissemination. The data are discussed with respect to the comparative effects on malaria vectorial capacity of life shortening and direct inhibition of Plasmodium development that can be produced by Wolbachia

Consensus-Phenotype Integration of Transcriptomic and Metabolomic Data Implies a Role for Metabolism in the Chemosensitivity of Tumour Cells

Using transcriptomic and metabolomic measurements from the NCI60 cell line panel, together with a novel approach to integration of molecular profile data, we show that the biochemical pathways associated with tumour cell chemosensitivity to platinum-based drugs are highly coincident, i.e. they describe a consensus phenotype. Direct integration of metabolome and transcriptome data at the point of pathway analysis improved the detection of consensus pathways by 76%, and revealed associations between platinum sensitivity and several metabolic pathways that were not visible from transcriptome analysis alone. These pathways included the TCA cycle and pyruvate metabolism, lipoprotein uptake and nucleotide synthesis by both salvage and de novo pathways. Extending the approach across a wide panel of chemotherapeutics, we confirmed the specificity of the metabolic pathway associations to platinum sensitivity. We conclude that metabolic phenotyping could play a role in predicting response to platinum chemotherapy and that consensus-phenotype integration of molecular profiling data is a powerful and versatile tool for both biomarker discovery and for exploring the complex relationships between biological pathways and drug response

Determining Temperature Preference of Mosquitoes and Other Ectotherms.

Most insects and other ectotherms have a relatively narrow optimal temperature window, and deviation from their optima can have significant effects on their fitness, as well as other characteristics. Consequently, many such ectotherms seek out their optimal temperature range. Although temperature preferences of mosquitoes and other insects have been well studied, the traditional experimental setup is performed using a temperature gradient on an aluminum surface in a highly enclosed space. In some cases, this equipment restricts many natural behaviors, such as flying, which may be important in preference selection. The objective of this study is to observe insect preference for air temperature by using a two-chamber apparatus with sufficient room for flight. The two chambers consist of independent temperature-controlled incubators, each with a large aperture. The incubators are connected by these apertures using a short acrylic bridge. Inside the incubators are two netted cages, linked via the apertures and bridge, allowing the insects to freely fly between the different conditions. The acrylic bridge also acts as a temperature gradient between the two incubators. Due to the spacious area in the cage and easy construction, this method can be used to study any small ectotherm and/or any manipulation which may alter temperature preference including sensory organ manipulation, diet, gut flora, and endosymbiont presence at biosafety levels 1 or 2 (BSL 1 or 2). Additionally, the apparatus can be used for the study of pathogen infection using further containment (e.g., inside of a biosafety cabinet) at BSL 3

Co-occurrence of viruses and mosquitoes at the vectors’ optimal climate range: An underestimated risk to temperate regions?

<div><p>Mosquito-borne viruses have been estimated to cause over 100 million cases of human disease annually. Many methodologies have been developed to help identify areas most at risk from transmission of these viruses. However, generally, these methodologies focus predominantly on the effects of climate on either the vectors or the pathogens they spread, and do not consider the dynamic interaction between the optimal conditions for both vector and virus. Here, we use a new approach that considers the complex interplay between the optimal temperature for virus transmission, and the optimal climate for the mosquito vectors. Using published geolocated data we identified temperature and rainfall ranges in which a number of mosquito vectors have been observed to co-occur with West Nile virus, dengue virus or chikungunya virus. We then investigated whether the optimal climate for co-occurrence of vector and virus varies between “warmer” and “cooler” adapted vectors for the same virus. We found that different mosquito vectors co-occur with the same virus at different temperatures, despite significant overlap in vector temperature ranges. Specifically, we found that co-occurrence correlates with the optimal climatic conditions for the respective vector; cooler-adapted mosquitoes tend to co-occur with the same virus in cooler conditions than their warmer-adapted counterparts. We conclude that mosquitoes appear to be most able to transmit virus in the mosquitoes’ optimal climate range, and hypothesise that this may be due to proportionally over-extended vector longevity, and other increased fitness attributes, within this optimal range. These results suggest that the threat posed by vector-competent mosquito species indigenous to temperate regions may have been underestimated, whilst the threat arising from invasive tropical vectors moving to cooler temperate regions may be overestimated.</p></div

Optimal mosquito season for sub-countries.

<p>Maps showing A: the period of the OMS as defined by the model parameters described in the methods; B the mean temperature of this season. Areas coloured in grey have insufficient data for this analysis.</p

Vector mean OMS temperatures.

<p>Vector mean OMS temperatures.</p

Transmission risk of two example mosquito species.

<p>Despite significant overlap in temperature envelopes (red boxes), Species 1 (Sp 1) is more cold-adapted than Species 2 (Sp 2) and its envelope extends further into colder temperatures, and less far into warm temperatures. In scenario 1, the optimum temperature for virus transmission (shown as white line against grey shading) is the same for both Sp 1 and Sp 2, despite the different temperature envelopes of the vectors. Our hypothesis corresponds to scenario 2, where the optimum temperature for virus transmission is lower for cooler-adapted Sp 1, and higher for warmer-adapted Sp 2.</p

CHIKV challenge.

<p>Mosquitoes were allowed to feed on artificial blood meals containing virus suspension and 7 days post infection 35–50 females were used for forced salivation. Samples were titrated by focus fluorescent assay on <i>Ae. albopictus</i> C6/36 cells. The transmission rate was estimated as the percentage of mosquitoes with infectious saliva among tested mosquitoes (A). Saliva samples were titrated by focus fluorescent assay on C6/36 <i>Ae. albopictus</i> cell culture. The total number of plaques was counted and the titer was calculated as FFU/saliva (B). No significant difference was found between Uju.wt and UjuT viral titers using a Wilcoxon rank sum test.</p

Mating competitiveness of Uju.wMel males.

<p>Competitiveness of Uju.wMel males was assessed using three independent replicates of 50 male Uju.wMel : 50 male Uju.wt (<i>w</i>AlbA/B) : 50 females of either Uju.wMel or Uju.wt (total of 300 females in six cages). Hatching embryos indicated a compatible cross where both male and female parents were infected with the same <i>Wolbachia</i>. Error bars show the SEM. No significant differences in male mating competitiveness were found between the two lines with Chi-squared analysis using a likelihood framework.</p

Known and potential vectors of West Nile virus, chikungunya virus and dengue virus listed in the EID2 database.

<p>Known and potential vectors of West Nile virus, chikungunya virus and dengue virus listed in the EID2 database.</p