Population genetic studies of the tsetse fly, Glossina pallidipes (Diptera: Glossinidae)

Tsetse flies transmit trypanosome species that cause sleeping sickness in humans and nagana in livestock. In the absence of a vaccine against trypanosome parasites and given the high cost of treatment, vector control remains the most effective method for reducing the incidence of trypanosomiasis. In anticipation of area-wide control of G. pallidipes by using genetic methods, a thorough understanding of its breeding structure is required.;Capture release-recapture data show that G. pallidipes has a high capacity for dispersal, but genetic data indicate surprisingly high differentiation among populations. Studying local patterns of genetic variation and examining how such variation changes temporally can provide insight into the apparent contradiction between ecological and genetic data. The overall objective of my research was to determine microgeographic (200 m--≤10 km) genetic structure of G. pallidipes and compare with population structure at the macrogeographic (tens to hundreds of kilometers) scale. In addition, I wanted to assess temporal changes in gene diversity and differentiation.;Microsatellite DNA loci were characterized and used to study genetic variation within and among natural G. pallidipes populations. The loci were highly polymorphic (mean number of alleles = 20.5 +/- 10.1) and unlinked hence useful for population studies. Mating was random within but not among populations at the macrogeographic scale (F ST = 0.18). Differentiation among microgeographic populations was minimal (FST = 0.017) indicating a high rate of gene flow at microgeographic scale. Allele frequencies were homogeneous among sampling sites. Analysis of molecular variance (AMOVA) showed that most of the variation (\u3e90%) lay within sites while only 2% of the total variance was attributed to variation among blocks.;Allele frequencies were homogenous between seasons. Genetic differentiation was higher in the dry season than in the wet season. However, differentiation between pooled wet and pooled dry season samples did not differ significantly from zero (FST = 0.008, G ST = 0.004). AMOVA showed that less than 2% of the variance could be attributed to difference between temporal samples. It is concluded that tsetse populations show little temporal variation probably due to drift. These results provide a better understanding of levels of genetic subdivision and gene flow at the local scale

Potential of anaerobic co-digestion in improving the environmental quality of agro-textile wastewater sludge

This research article published by IWA publishingSludge from textile effluent treatment plants (ETP) remains a challenge for many industries due to inefficient and limited waste management strategies. This study explores the potential of using anaerobic digestion (AD) to improve the environmental quality of textile ETP sludge. The AD of ETP sludge is affected by the low C/N ratio (3.7), heavy metal content, and toxicity. To improve the process, co-digestion of ETP sludge with different substrates (sewage sludge, cow dung, and sawdust) under mesophilic conditions (37 °C), followed by a thermochemical pretreatment was assessed. The results showed that anaerobic co-digestion of the textile sludge with the co-substrates is effective in reducing pollution load. It was found that organic matters degraded during the 30-day AD process. The chemical oxygen demand and biological oxygen demand reduction was in the range of 33.1–88.5% and 48.1–67.1%, respectively. Also, heavy metal (cadmium, lead, iron, and, mercury) concentration was slightly reduced after digestion. Maximal biogas yield was achieved from co-digestion of textile sludge and sewage sludge at a mixing ratio of 3:1, 1:1, and 1:3, and methane content was respectively 87.9%, 68.9%, and 69.5% of the gas composition. The results from this study show that co-digestion will not only reduce the environmental pollution and health risks from the textile industry but also recover useful energy