Insects have evolved various physiological responses to cope with stressors such as pathogens, toxins and environmental factors. It is known that the responses resulting from infection or DNA damage share some of the same pathways. Exposure of Drosophila melanogaster and the dung beetle Euoniticellus intermedius to stress led to changes in the expression of proteins involved in metabolism, development, protein degradation, mRNA processing and stress responses. Stress responses in D. melanogaster are well characterised. However, the role played by Drosophila p53 (Dmp53) and a member of the retinoblastoma binding protein 6 (RBBP6) family, Snama, are unknown. Snama has been proposed to play a role in Dmp53 regulation. Following DNA damage we investigated the role of Dmp53 and Snama. Flies recovering from camptothecin treatment display a glycolytic flux, involving a metabolic shift, different to that observed in cancer cells. Camptothecin treatment leads to an increase in the mortality of both sexes. Furthermore, females show a specific decrease in fecundity which is due to an increase in Dmp53 dependent apoptosis in the ovaries and is accompanied by a depletion of Snama and an increase in Dmp53 transcripts. Expression data indicated that Dmp53 activity may be largely regulated at the protein level. Bypassing glycolysis through methyl pyruvate supplementation led to differential expression of Dmp53 and Snama and improved reproduction and embryonic development. These results highlight differences between the metabolic strategies used by cancerous and non-cancerous cells which may be exploited in future chemotherapies. While immune responses amongst insect orders are evolutionarily conserved, many remain uncharacterised. To investigate the immune system of an organism that lives in a microbe rich environment, E. intermedius was infected with the fungal pathogen Beauveria bassiana. This resulted in decreased lifespan and fecundity. Homologs of proteins involved in the immune response of insects were identified in E. intermedius, including a member of the Toll family of proteins, an insect defensin (present in the hemolymph) as well as a homolog of the serine protease Persephone. These results show that immune signalling pathways are conserved in this dung beetle.

In malaria-endemic regions, Plasmodium falciparum (P. falciparum) infection is characterized by extensive genetic/antigenic diversity. Describing this diversity provides important information about the local molecular epidemiology of infecting P. falciparum parasites. Intriguingly, one of the major obstacles to the development of an effective malaria vaccine has been the genetic polymorphisms exhibited by P. falciparum genes encoding targets of human immune system. This situation has necessitated the development of polyvalent vaccines with wide antigenic coverage that would increase the likelihood of vaccine efficacy that covers wide geographical areas of malaria endemic countries. Limited reports are available on the population genetic diversity and structure of P. falciparum in Malawi, and this is of particular concern as the country has put in place several interventions to combat the disease. The primary aim of the research project was to determine the genetic diversity and population structure of P. falciparum isolates and comparing complexity from four different epidemiological settings in Malawi using msp-2 gene polymorphisms. Samples were collected from four epidemiological locations in the north, centre and southern regions of Malawi. The diversity and genetic differentiation of P. falciparum populations were analyzed based on the highly polymorphic block 3 msp-2 gene. One hundred and twenty patient samples who presented with signs and symptoms of malaria and who had microscopically confirmed P. falciparum infection were enrolled in the study after they had satisfied the inclusion criteria. Parasite DNA was extracted from the blood spot on to filter paper and analyzed by genotyping the msp-2 gene using allele-specific nested PCR. A total of 28 msp-2 block 3 fragments, defined by the size and the allelic types were detected in the 102 patients. The length variants of the PCR product ranged from 240basepairs (bp) to 450bp for the K1/FC and 410bp to 780bp for the 3D7/IC allelic families. Isolates of the 3D7 alleles were predominant in the population (59 percent), compared to isolates of the K1/ FC27 alleles (41 percent) and for 3D7 and K1 most of the isolates were monoclonal infections. In comparisons between the sites, we observed the highest prevalence of mixed infection in Mwanza (46.7 percent) followed by Dwangwa (23.3 percent) compared to Bolero (16.7 percent) and Mitundu (16.7 percent). The difference in prevalence of mixed infections between Mwanza and the other sites was statistically significant (p=0.041). There was also a non-significant trend towards a higher mean genotype number per isolate in the children aged >5 years compared to those below 5 years of age. These data suggest differences in prevalence rates of mixed infections in different geographical/epidemiological settings in Malawi. Further studies are needed to confirm, with larger sample sizes, the observation of a non-significant trend towards higher multiclonality of infection in older children in malaria endemic areas of Malawi.