The majority of mitochondrial proteins are encoded in the nucleus and need to be imported from the cytosol into the mitochondria, and molecular chaperones play a key role in the efficient translocation and proper folding of these proteins in the matrix. One such molecular chaperone is the eukaryotic mitochondrial heat shock protein 70 (Hsp70); however, it is prone to self-aggregation and requires the presence of an essential zinc-finger protein, Hsp70-escort protein 1 (Hep1), to maintain its structure and function. PfHsp70-3, the only Hsp70 predicted to localize in the mitochondria of P. falciparum, may also rely on a Hep1 orthologue to prevent self-aggregation. In this study, we identified a putative Hep1 orthologue in P. falciparum and co-expression of PfHsp70-3 and PfHep1 enhanced the solubility of PfHsp70-3. PfHep1 suppressed the thermally induced aggregation of PfHsp70-3 but not the aggregation of malate dehydrogenase or citrate synthase, thus showing specificity for PfHsp70-3. Zinc ions were indeed essential for maintaining the function of PfHep1, as EDTA chelation abrogated its abilities to suppress the aggregation of PfHsp70-3. Soluble and functional PfHsp70-3, acquired by co-expression with PfHep-1, will facilitate the biochemical characterisation of this particular Hsp70 protein and its evaluation as a drug target for the treatment of malaria.

Hsp70 members occupy a central role in proteostasis and are found in different eukaryotic cellular compartments. The mitochondrial Hsp70/J-protein machinery performs multiple functions vital for the proper functioning of the mitochondria, including forming part of the import motor that transports proteins from the cytosol into the matrix and inner membrane, and subsequently folds these proteins in the mitochondria. However, unlike other Hsp70s, mitochondrial Hsp70 (mtHsp70) has the propensity to self-aggregate, accumulating as insoluble aggregates. The self-aggregation of mtHsp70 is caused by both interdomain and intramolecular communication within the ATPase and linker domains. Since mtHsp70 is unable to fold itself into an active conformation, it requires an Hsp70 escort protein (Hep) to both inhibit self-aggregation and promote the correct folding. Hep1 orthologues are present in the mitochondria of many eukaryotic cells but are absent in prokaryotes. Hep1 proteins are relatively small and contain a highly conserved zinc-finger domain with one tetracysteine motif that is essential for binding zinc ions and maintaining the function and solubility of the protein. The zinc-finger domain lies towards the C-terminus of Hep1 proteins, with very little conservation outside of this domain. Other than maintaining mtHsp70 in a functional state, Hep1 proteins play a variety of other roles in the cell and have been proposed to function as both chaperones and co-chaperones. The cellular localisation and some of the functions are often speculative and are not common to all Hep1 proteins analysed to date.

Malaria remains a global health burden accounting for many deaths and illnesses in sub-Saharan Africa notwithstanding many decades of research on the disease. P. falciparum, the causative agent of the most fatal form of malaria, expresses a repertoire of heat shock proteins (Hsp) that cushion the parasite against heat shocks as it shuttles between extreme temperatures in human and mosquito vector hosts. By so doing, such proteins promote parasite’s cytoprotection, survival and pathogenesis. Heat shock proteins are named according to their molecular weights and there are six P. falciparum Hsp70 (PfHsp70) found in various cell compartments with mitochondrial putative PfHsp70-3. Using indirect immunofluorescence, this study established mitochondrial localization of PfHsp70-3 though some more confirmatory studies would be needed in the future. PfHsp70-3 was found to be heat inducible and expressed during all stages of the intra-erythrocytic cycle of parasite development. This could be an indication of PfHsp70-3’s involvement in the infectivity process of P. falciparum by helping the parasite to resist heat shocks during malaria febrile episodes. Generally, the data obtained in this study will enhance the existing knowledge on the biology of P. falciparum mitochondrial heat shock protein functions and open possible avenues for targeting the specificity between PfHsp70-3 and its co-chaperones for drug development. Keywords: Malaria, P. falciparum, Heat shock proteins, PfHsp70-3, pathogenesis

Malnutrition remains a challenge in Tanzania, notwithstanding government initiatives and health education geared towards assuaging the problem. According to the World Health Organization (WHO), there will be more than 600,000 severely malnourished children in Tanzania by the year 2030. In particular, protein based malnutrition remains the greatest challenge due to the irreplaceable nature of its essential amino acids. Macronutrients and micronutrients which are found in Spirulina platensis have been recommended by WHO to address malnutrition in developing countries. Spirulina platensis is a filamentous Cyanobacterium microalgae with the highest recorded protein content of plant origin with several immune boosting nutrients. Spirulina cultivation requires sufficient aeration, proper light intensity and salinity for maximum biomass yield, cell productivity, specific growth rate, and protein content. This paper presents the findings of a study carried out in Kilimanjaro on the optimized conditions, locally and economically tailored approach system required to grow spirulina in the region. The study established the use of food grade organic media with low-cost urea as nitrogen source, a greenhouse average temperature of 30–32 °C in the months between December to March, alkalinity of 5 g/L, mixing frequency of 3 times per day/100 L  and partial shading, as the optimum conditions for outdoor cultivation of spirulina. Keywords: Malnutrition, Spirulina, Protein, growth condition