Allelic Gene Structure Variations in Anopheles gambiae Mosquitoes

Allelic gene structure variations and alternative splicing are responsible for transcript structure variations. More than 75% of human genes have structural isoforms of transcripts, but to date few studies have been conducted to verify the alternative splicing systematically.The present study used expressed sequence tags (ESTs) and EST tagged SNP patterns to examine the transcript structure variations resulting from allelic gene structure variations in the major human malaria vector, Anopheles gambiae. About 80% of 236,004 available A. gambiae ESTs were successfully aligned to A. gambiae reference genomes. More than 2,340 transcript structure variation events were detected. Because the current A. gambiae annotation is incomplete, we re-annotated the A. gambiae genome with an A. gambiae-specific gene model so that the effect of variations on gene coding could be better evaluated. A total of 15,962 genes were predicted. Among them, 3,873 were novel genes and 12,089 were previously identified genes. The gene completion rate improved from 60% to 84%. Based on EST support, 82.5% of gene structures were predicted correctly. In light of the new annotation, we found that approximately 78% of transcript structure variations were located within the coding sequence (CDS) regions, and >65% of variations in the CDS regions have the same open-reading-frame. The association between transcript structure isoforms and SNPs indicated that more than 28% of transcript structure variation events were contributed by different gene alleles in A. gambiae.We successfully expanded the A. gambiae genome annotation. We predicted and analyzed transcript structure variations in A. gambiae and found that allelic gene structure variation plays a major role in transcript diversity in this important human malaria vector

Regreening Africa: Consolidated Baseline Survey Report

The United Nations General Assembly declared 2021 to 2030 as the decade of ‘ecosystem restoration’, signalling a global consensus on the urgency to restore degraded lands. Restoring degraded lands is critical to regain lost ecological functionality that underpins life-sustaining ecosystem services, such as the provision of food, fresh water, and fibre, and the regulation of climate, natural disasters, and pests. Indeed, restoration is fundamental for meeting the triple goals of tackling the climate crisis, reversing biodiversity loss, and improving human wellbeing. Regreening Africa (2017 to 2022) is part of a larger global and regional effort to reverse and halt land degradation, which is being implemented in eight African countries: Ethiopia, Ghana, Kenya, Mali, Niger, Rwanda, Senegal, and Somalia

Forest Gardens as an 'intermediate' land-use system in the nature-culture continuum: Characteristics and future potential

Forest gardens are reconstructed natural forests, in which wild and cultivated plants coexist, such that the structural characteristics and ecological processes of natural forests are preserved, although the species composition has been adapted to suit human needs. These agroforests include a range of modified and transformed forests, and form an integral part of local land-use systems. They lie between natural forests and tree-crop plantations in terms of their structure and composition, and low intensity of forest extraction systems and the high intensity plantation systems in terms of their management intensity. Their management is characterized by combined use of silvicultural and horticultural operations, and spatial and temporal variations. These ecologically sustainable systems are often dynamic in species composition in response to changing socioeconomic conditions. Evolved over a long period of time as a result of local community's creativity, forest gardens have still received little attention in agroforestry research, just as in the case of the more intensively domesticated homegardens. The study of forest gardens offers good opportunities for obtaining a better understanding of the 'nature-analogous' agroforestry systems and for developing multifunctional agroforestry systems combining production and biodiversity values

Solute carriers affect Anopheles stephensi survival and Plasmodium berghei infection in the salivary glands

Malaria is caused by mosquito-borne Plasmodium spp. parasites that must infect and survive within mosquito salivary glands (SGs) prior to host transmission. Recent advances in transcriptomics and the complete genome sequencing of mosquito vectors have increased our knowledge of the SG genes and proteins involved in pathogen infection and transmission. Membrane solute carriers are key proteins involved in drug transport and are useful in the development of new interventions for transmission blocking. Herein, we applied transcriptomics analysis to compare SGs mRNA levels in Anopheles stephensi fed on non-infected and P. berghei-infected mice. The A. stephensi solute carriers prestinA and NDAE1 were up-regulated in response to infection. These molecules are predicted to interact with each other, and are reportedly involved in the maintenance of cell homeostasis. To further evaluate their functions in mosquito survival and parasite infection, these genes were knocked down by RNA interference. Knockdown of prestinA and NDAE1 resulted in reduction of the number of sporozoites in mosquito SGs. Moreover, NDAE1 knockdown strongly impacted mosquito survival, resulting in the death of half of the treated mosquitoes. Overall, our findings indicate the importance of prestinA and NDAE1 in interactions between mosquito SGs and Plasmodium, and suggest the need for further research.publishersversionpublishe