Biogeographical survey of soil microbiomes across sub-Saharan Africa: structure, drivers, and predicted climate-driven changes.

BACKGROUND: Top-soil microbiomes make a vital contribution to the Earth's ecology and harbor an extraordinarily high biodiversity. They are also key players in many ecosystem services, particularly in arid regions of the globe such as the African continent. While several recent studies have documented patterns in global soil microbial ecology, these are largely biased towards widely studied regions and rely on models to interpolate the microbial diversity of other regions where there is low data coverage. This is the case for sub-Saharan Africa, where the number of regional microbial studies is very low in comparison to other continents. RESULTS: The aim of this study was to conduct an extensive biogeographical survey of sub-Saharan Africa's top-soil microbiomes, with a specific focus on investigating the environmental drivers of microbial ecology across the region. In this study, we sampled 810 sample sites across 9 sub-Saharan African countries and used taxonomic barcoding to profile the microbial ecology of these regions. Our results showed that the sub-Saharan nations included in the study harbor qualitatively distinguishable soil microbiomes. In addition, using soil chemistry and climatic data extracted from the same sites, we demonstrated that the top-soil microbiome is shaped by a broad range of environmental factors, most notably pH, precipitation, and temperature. Through the use of structural equation modeling, we also developed a model to predict how soil microbial biodiversity in sub-Saharan Africa might be affected by future climate change scenarios. This model predicted that the soil microbial biodiversity of countries such as Kenya will be negatively affected by increased temperatures and decreased precipitation, while the fungal biodiversity of Benin will benefit from the increase in annual precipitation. CONCLUSION: This study represents the most extensive biogeographical survey of sub-Saharan top-soil microbiomes to date. Importantly, this study has allowed us to identify countries in sub-Saharan Africa that might be particularly vulnerable to losses in soil microbial ecology and productivity due to climate change. Considering the reliance of many economies in the region on rain-fed agriculture, this study provides crucial information to support conservation efforts in the countries that will be most heavily impacted by climate change. Video Abstract.

Future of plant science in Zimbabwe.

Zimbabwe's agricultural biotechnology research capacity is located at universities, government research institutions and parastatal (state funded) organizations. Projects range from those using traditional biotechnology to a few that are experimenting with genetically modified organisms (GMOs).

[Longitudinal study of puberty in Dakar]. / Etude longitudinale de la puberté à Dakar.

A longitudinal survey of some characteristics of puberty was performed on a group of Dakarese adolescents, who had previously been followed up from birth to 6 years of age. The collected data were used to determine (1) the dispersion of ages when these characteristics began to appear, and the relationships between various aspects of puberty; (2) the relationships between some pubertal criteria and the end of the growth process and (3) those existing between nutritional status in early childhood and puberty itself. Some comparisons have been made with the results of a longitudinal survey concerning Londonian adolescents.

"Topical nephropathy" and "tropical extramembranous glomerulonephritis" of unknown aetiology in Senegal.

A study of renal biopsy specimens obtained in Senegal from 24 children and six adults with nephrotic syndrome showed two unusual varieties of nephropathy--namely, an extramembranous glomerulonephritis associated with hypocomplementaemia (four cases), a combination previously described only in systemic lupus erythematosus, and a "tropical nephropathy" (16 cases). The latter, though lacking the diffuse glomerular deposits of immunoglobulin described in quartan malarial nephropathy (Q.M.N.), showed a curious progressive and segmental glomerulosclerosis, characterized by a "flaking" or fibrillary splitting of the glomerular capillary wall, seen in Q.M.N. Serological evidence of malaria was lacking in a third of the childhood cases.

Sequence of the 3'-terminal region of a Zimbabwe isolate of cowpea aphid-borne mosaic virus (CABMV).

The 3'-terminal 1221 nucleotides of a Zimbabwe isolate of cowpea aphid-borne mosaic potyvirus (CABMV) genome have been sequenced. The sequence comprises an open reading frame (ORF) of 990 nucleotides and a 3' non-coding-region of 231 nucleotides followed by a poly-A. The ORF has high similarity to NIb and coat proteins (CP) of potyviruses. A potential CP Q/S cleavage site was identified, yielding a CP of 30.5 kDa containing 275 amino acids. The CABMV sequence is closely related to that of South African passiflora virus (SAPV) which should therefore be regarded as a strain of CABMV.

The genomic sequence of cowpea aphid-borne mosaic virus and its similarities with other potyviruses.

The genomic sequence of a Zimbabwe isolate of Cowpea aphid-borne mosaic virus (CABMV-Z) was determined by sequencing overlapping viral cDNA clones generated by RT-PCR using degenerate and/or specific primers. The sequence is 9465 nucleotides in length excluding the 3' terminal poly (A) tail and contains a single open reading frame (ORF) of 9159 nucleotides encoding a large polyprotein of 3,053 amino acids and predicted Mr of 348. The size of the genome and the encoded polyprotein is in agreement with other potyviruses and contains nine putative proteolytic cleavage sites and motifs conserved in homologous proteins of other potyviruses. The P1 and P3 were the most variable proteins while CI, NIb and CP were the most conserved.