Role of healthy-looking banana and alternate hosts in the spread of banana bunchy top disease

Poster presented at Symposium of the Pest Management Council of the Philippines. 200

Proteomic analysis of the Plasmodium male gamete reveals the key role for glycolysis in flagellar motility.

BACKGROUND: Gametogenesis and fertilization play crucial roles in malaria transmission. While male gametes are thought to be amongst the simplest eukaryotic cells and are proven targets of transmission blocking immunity, little is known about their molecular organization. For example, the pathway of energy metabolism that power motility, a feature that facilitates gamete encounter and fertilization, is unknown. METHODS: Plasmodium berghei microgametes were purified and analysed by whole-cell proteomic analysis for the first time. Data are available via ProteomeXchange with identifier PXD001163. RESULTS: 615 proteins were recovered, they included all male gamete proteins described thus far. Amongst them were the 11 enzymes of the glycolytic pathway. The hexose transporter was localized to the gamete plasma membrane and it was shown that microgamete motility can be suppressed effectively by inhibitors of this transporter and of the glycolytic pathway. CONCLUSIONS: This study describes the first whole-cell proteomic analysis of the malaria male gamete. It identifies glycolysis as the likely exclusive source of energy for flagellar beat, and provides new insights in original features of Plasmodium flagellar organization

Transmission-Blocking Vaccines: Focus on Anti-Vector Vaccines against Tick-Borne Diseases

Tick-borne diseases are a potential threat that account for significant morbidity and mortality in human population worldwide. Vaccines are not available to treat several of the tick-borne diseases. With the emergence and resurgence of several tick-borne diseases, emphasis on the development of transmission-blocking vaccines remains increasing. In this review, we provide a snap shot on some of the potential candidates for the development of anti-vector vaccines (a form of transmission-blocking vaccines) against wide range of hard and soft ticks that include Ixodes, Haemaphysalis, Dermacentor, Amblyomma, Rhipicephalus and Ornithodoros species

Cytoplasmic Incompatibility as a Means of Controlling Culex pipiens quinquefasciatus Mosquito in the Islands of the South-Western Indian Ocean

The use of the bacterium Wolbachia is an attractive alternative method to control vector populations. In mosquitoes, as in members of the Culex pipiens complex, Wolbachia induces a form of embryonic lethality called cytoplasmic incompatibility, a sperm-egg incompatibility occurring when infected males mate either with uninfected females or with females infected with incompatible Wolbachia strain(s). Here we explore the feasibility of the Incompatible Insect Technique (IIT), a species-specific control approach in which field females are sterilized by inundative releases of incompatible males. We show that the Wolbachia wPip(Is) strain, naturally infecting Cx. p. pipiens mosquitoes from Turkey, is a good candidate to control Cx. p. quinquefasciatus populations on four islands of the south-western Indian Ocean (La Réunion, Mauritius, Grande Glorieuse and Mayotte). The wPip(Is) strain was introduced into the nuclear background of Cx. p. quinquefasciatus mosquitoes from La Réunion, leading to the LR[wPip(Is)] line. Total embryonic lethality was observed in crosses between LR[wPip(Is)] males and all tested field females from the four islands. Interestingly, most crosses involving LR[wPip(Is)] females and field males were also incompatible, which is expected to reduce the impact of any accidental release of LR[wPip(Is)] females. Cage experiments demonstrate that LR[wPip(Is)] males are equally competitive with La Réunion males resulting in demographic crash when LR[wPip(Is)] males were introduced into La Réunion laboratory cages. These results, together with the geographic isolation of the four south-western Indian Ocean islands and their limited land area, support the feasibility of an IIT program using LR[wPip(Is)] males and stimulate the implementation of field tests for a Cx. p. quinquefasciatus control strategy on these islands

Platform for Plasmodium vivax vaccine discovery and development

Plasmodium vivax is the most prevalent malaria parasite on the American continent. It generates a global burden of 80-100 million cases annually and represents a tremendous public health problem, particularly in the American and Asian continents. A malaria vaccine would be considered the most cost-effective measure against this vector-borne disease and it would contribute to a reduction in malaria cases and to eventual eradication. Although significant progress has been achieved in the search for Plasmodium falciparum antigens that could be used in a vaccine, limited progress has been made in the search for P. vivax components that might be eligible for vaccine development. This is primarily due to the lack of in vitro cultures to serve as an antigen source and to inadequate funding. While the most advanced P. falciparum vaccine candidate is currently being tested in Phase III trials in Africa, the most advanced P. vivax candidates have only advanced to Phase I trials. Herein, we describe the overall strategy and progress in P. vivax vaccine research, from antigen discovery to preclinical and clinical development and we discuss the regional potential of Latin America to develop a comprehensive platform for vaccine development

Ensuring virus-free banana germplasm for long-term conservation and dissemination

Poster presented at 16th National Fruit Symposium of the Philippine Fruit Association. Splash Mountain Resort, Los Banos, 14-16 Oct 200

Response of wild and edible Musa spp. seedlings to limiting moisture stress

Banana, one of the world's leading crops is predicted to be highly vulnerable to drought conditions brought about by climate change. Identification of drought tolerant cultivars is one of the long term strategies of addressing the effect of climate change. The National Plant Genetic Resources Laboratory and the Bureau of Plant Industry of the Philippine Department of Agriculture maintain germplasm collections of edible and wild Musa spp. from the Philippines, Southeast Asia and Papua New Guinea (SEA/PNG) that have not been assessed for drought tolerance. Thus, this study was conducted to assess the drought response of 29 Musa genotypes from the germplasm collections at seedling stage under greenhouse condition. Drought was imposed on 3 mo-old tissue culture-derived seedlings by withholding water for 2-3 wk, while control plants were watered regularly. Under drought condition, the genotypes differed significantly in terms of plant growth, number of leaf cigars formed, specific leaf area, biomass production and partitioning as well as water use efficiency across water treatment. Only 28% of the banana genotypes allocated more biomass to the roots. Total leaf area production was influenced by significant interaction between water treatment and genotype. Significant genotypic differences in terms of relative leaf folding (RLF) and stomata! conductance were observed, with increased RLF as soil moisture content decreased. Stomatal conductances were significantly affected by the interaction between genotype and time of sampling. The genotypes also differed significantly in their water use efficiency (WUE) with increases ranging 1-70% under drought. WUE was found to be positively correlated with total plant dry weight, root volume, root dry weight and relative leaf folding. Based on the relative performance under drought cultivar, "Gubao" (BBB) is the most drought tolerant based on total biomass production, root dry weight, root volume and WUE followed by 'P.K. Malaccacina" and "Tindok"