Molecular Identification and Characterization of a Begomovirus Associated with Okra Enation Leaf Curl Disease in Mali

Okra is one of the most widespread vegetable crops in the world, particularly in West Africa. However, several factors influence okra crops as biotic and abiotic factors. Among the diseases affecting its culture, okra leaf curl disease is a major threat. This study aims to assess begomoviruses from okra plants with symptoms like leaves curl by molecular approach. A total of thirteen serologically positive samples were tested by PCR assay, and one sample was sequenced among them. The begomovirus was found in six isolates, Bhendi yellow vein mosaic virus (BYVMV) in three isolates, and Okra enation leaf curl virus (OELCuV) in three isolates, respectively. The begomovirus isolate sequences shared 90% identity with the Cotton leaf curl Gezira virus. Mixed infections between these viruses were found. Thus, these results highlight the need to monitor the spread of these disease-causing viruses for okra crops in Mali. In addition, they can also lead to a considerable loss in okra fields in Koulikoro, which is an agricultural region by excellence.

Mutations in Spike Gene of SARS-CoV-2 that Are Associated with a Higher Viral Load: A Clinical Case Study

Background: Quantitative PCR (qPCR) can be used to detect and quantify a load of a pathogen. It is a good indicator of the degree of transmissibility. While performing routine qPCR, we observed an unusually short cycle threshold (Ct) value of SARS-CoV-2 for a clinical specimen obtained in Bamako, Mali. This prompted us to sequence the short-cycle SARS-CoV-2 sample to identify potential mutations in the Spike gene (S gene) gene. Methods: Post-infection, Quantitative Reverse Transcription (qRT-PCR) was performed over a defined time course to estimate the Ct of the SARS-CoV-2 specimen collected from the patient. Sanger sequencing was done on the entire fragment of the S gene to identify mutations. Findings: Sanger sequencing revealed mutations in the lineage of interest, designated B.1.525 by Pango, and also known as “Eta” using the nomenclature defined by WHO. This variant was originally found in Nigeria and Italy. The four novel mutations identified in Eta (D228N, Y451N, I1172M, and C1250F) were otherwise observed with a low frequency worldwide. Although the initial Ct was 10 in the case study patient, he did not exhibit severe symptoms of SARS-CoV-2, for example, pneumonia. However, we observed a longer viral clearance period than usual, of 3 weeks. We note that as compared to SARS-CoV-2 samples obtained during the first peaks of SARS-CoV-2 infection in Mali, when the infection was at its peak in March 2020 (Ct = 30.4), circulating strains evaluated at the time the Eta sample was obtained demonstrated a lower mean Ct (Ct = 24). Conclusions: The short cycle threshold associated with this variant, and the temporal association with a decrease in the mean Ct in the region of Bamako, may indicate higher levels of transmissibility due to a circulating variant. This variant is a lineage of interest designated B.1.525 by Pango or Eta by WHO.

Assessment of Heavy Metals and Microbial Pollution of Lettuce (<i>Lactuca sativa</i>) Cultivated in Two Sites (Paspanga and Tanghin) of Ouagadougou, Burkina Faso

Environmental pollution can have detrimental effects on crop yield and its consumers. The current study was designed to investigate the potential human health risks associated with the consumption of lettuce crop contaminated with toxic heavy metals and microbiological status. Irrigated water, soil and lettuce were analyzed by AAS technics for heavy metals including Cd, Cr, Cu, Mn, Ni, Pb and Zn. Transfer factor (TF), daily intake of metals (DIM) and health risk index (HRI) were also calculated. Microbial analysis was carried out for the presence foodborne pathogens. The results showed that the heavy metals contents were higher in the soil than wastewater and the vegetables. Heavy metals ranged (mg·Kg-1) for Cd (1.27 to 2.93), Cr (7.28 to 7.38), Cu (0.91 to 1.70), Mn (0.29 to 6.60), Ni (1.74 to 2.16), Pb (1.32 to 1.69), Zn (3.08 to 3.79);and were higher than the WHO maximum limit permissible (ML) in vegetables. HRI TF values designated an enhanced bio-contamination. Microbial numeration revealed the presence of spoiler and pathogenic microorganisms. The lettuce tested was not safe for human use, especially for direct consumption by human beings.

Isolation and Identification of Indigenous Yeasts from “<i>Rabil&eacute;</i>”, a Starter Culture Used for Production of Traditional Beer “<i>dolo</i>”, a Condiment in Burkina Faso

Rabilé is a ferment of dolo, a traditional sorghum beer of Burkina Faso and it is harvested at the end of dolo fermentation process. It is a significant source of proteins and it is used like a condiment and food seasoning by some communities. The present study characterized and identified the yeasts isolated from Rabilé. A total of 70 samples were collected from 7 localities of Burkina Faso with dolo sellers according to the ethnic groups. The aerobic mesophilic flora count from Rabilé varied from 8.34 ± 0.72 to 10.07 ± 0.51 log10 CFU·g-1 and yeast varied from 7.24 to 8.28 log10 UFC·g-1. Based on morphological, cultural, sexual and biochemical (carbon and nitrogen assimilation) profiles, 50 yeast strains were identified and found to belong to 4 genera and 7 species. Saccharomyces cerevisiae was found as most predominant yeasts species of yeast in of Rabilé with 64 %, Rhodotorula muciloginosa, (8%), Candida pseudorhangii (6%), Candida heliconiae (12%), Candida utilis (4%), Shizosaccharomyces pombe (4%) and Sporobolomyces odoratus (2%). This activity has been carried out in the Laboratory of Biotechnology for Food and Nutritional Sciences, University Ouaga I Pr Josph KY-ZERBO, Burkina Faso, and it was done from June to October 2018.