The evolving SARS-CoV-2 epidemic in Africa: Insights from rapidly expanding genomic surveillance

INTRODUCTION Investment in Africa over the past year with regard to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) sequencing has led to a massive increase in the number of sequences, which, to date, exceeds 100,000 sequences generated to track the pandemic on the continent. These sequences have profoundly affected how public health officials in Africa have navigated the COVID-19 pandemic. RATIONALE We demonstrate how the first 100,000 SARS-CoV-2 sequences from Africa have helped monitor the epidemic on the continent, how genomic surveillance expanded over the course of the pandemic, and how we adapted our sequencing methods to deal with an evolving virus. Finally, we also examine how viral lineages have spread across the continent in a phylogeographic framework to gain insights into the underlying temporal and spatial transmission dynamics for several variants of concern (VOCs). RESULTS Our results indicate that the number of countries in Africa that can sequence the virus within their own borders is growing and that this is coupled with a shorter turnaround time from the time of sampling to sequence submission. Ongoing evolution necessitated the continual updating of primer sets, and, as a result, eight primer sets were designed in tandem with viral evolution and used to ensure effective sequencing of the virus. The pandemic unfolded through multiple waves of infection that were each driven by distinct genetic lineages, with B.1-like ancestral strains associated with the first pandemic wave of infections in 2020. Successive waves on the continent were fueled by different VOCs, with Alpha and Beta cocirculating in distinct spatial patterns during the second wave and Delta and Omicron affecting the whole continent during the third and fourth waves, respectively. Phylogeographic reconstruction points toward distinct differences in viral importation and exportation patterns associated with the Alpha, Beta, Delta, and Omicron variants and subvariants, when considering both Africa versus the rest of the world and viral dissemination within the continent. Our epidemiological and phylogenetic inferences therefore underscore the heterogeneous nature of the pandemic on the continent and highlight key insights and challenges, for instance, recognizing the limitations of low testing proportions. We also highlight the early warning capacity that genomic surveillance in Africa has had for the rest of the world with the detection of new lineages and variants, the most recent being the characterization of various Omicron subvariants. CONCLUSION Sustained investment for diagnostics and genomic surveillance in Africa is needed as the virus continues to evolve. This is important not only to help combat SARS-CoV-2 on the continent but also because it can be used as a platform to help address the many emerging and reemerging infectious disease threats in Africa. In particular, capacity building for local sequencing within countries or within the continent should be prioritized because this is generally associated with shorter turnaround times, providing the most benefit to local public health authorities tasked with pandemic response and mitigation and allowing for the fastest reaction to localized outbreaks. These investments are crucial for pandemic preparedness and response and will serve the health of the continent well into the 21st century

Entre savoir scientifique et savoir vernaculaire. perception du changement climatique par les marins-pêcheurs de Medhia et Bousselham.

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An employee–employer relationship gone bad? Examining the double‐edged effect of psychological contract violation on employees' helping behaviors

An important concept that depicts the nature of employee–employer relationship is the psychological contract. Prior research has argued that all forms of extra‐role behaviors suffer once employees' psychological contracts are violated. Helping behaviors are a specific form of extra‐role behaviors that may suffer due to psychological contract violation. We argue that this predominantly negative relationship between psychological contract violation and helping behaviors is because the literature has not adequately examined the different types of helping behaviors. Using the latent moderated structural equation approach with multiwave and multisource data from a survey of 269 full‐time employees and their coworkers from the hospitality industry in Ghana, we show that psychological contract violation is positively related to reactive helping behaviors and negatively associated with anticipatory helping behaviors through anticipatory anxiety

Chemical composition, antioxidant and antimicrobial activities of essential oil obtained from wild and cultivated Moroccan Thymus species

Thymus broussonetii, Thymus maroccanus and Thymus satureioides, are endemic Moroccan species that are intensively utilized because of their wide ranging medicinal and culinary properties. In an effort to preserve these over-exploited species, the effect of cultivation on the essential oil chemical composition, antioxidant and antimicrobial activities were investigated. The hydrodistilled oils obtained from wild and cultivated thyme species were analyzed by GC–MS. In total, 41 components were identified representing more than 98% of the oils, with carvacrol (26.0–71.6%), borneol (5.0–20.1%), γ-terpinene (4.0–8.9%) and p-cymene (5.2–10.3%) as the main constituents. Similar oil profiles were obtained from wild and cultivated T. maroccanus, whereas some quantitative differences were noted between oils obtained from wild and cultivated T. broussonetii and T. satureioides. The antioxidant and antimicrobial assays revealed that all oils tested from wild and cultivated studied thyme species showed strong activities

In vitro antiplasmodial activity of Withania frutescens —Solanaceae

International audienceIntroduction: Drugs resistant Plasmodium falciparum is a recurring issue that threatens public health. New anti-plasmodial drugs are needed to overcome this problem. The aim of this study was to characterize in vitro an-tiplasmodial activity of Withania frutescens (Solanaceae) against chloroquine-resistant Plasmodium falciparum strain. Methods: The in vitro antiplasmodial activity of leaves and roots extracts from Withania frutescens was performed in 96 well plates and preliminary phytochemical analysis was performed for the active fractions. The toxicity of the plant extract against CHO (Chinese Hamster Ovary) cells was assessed using the tetrazolium salt MTT col-orimetric assay. The selectivity index (SI) was calculated as the ratio between the cytotoxic and antiparasitic activities. Results: The methanol extract of W. frutescens leaves showed a good antiplasmodial activity (CC 50 18.1 μg/ml). Furthermore, ethyl acetate and butanol fractions showed promising in vitro antiplasmodial activity with a se-lectivity index of 3.1 and 2.4, respectively. The roots of W. frutescens were found to be inactive with a CC 50 value > 80 μg/ml. Conclusion: The antiplasmodial activity of W. frutescens may in part be attributed to the presence of polyphenolic and flavonoid compounds. Based on our results, ethyl acetate and butanol leaves fractions could be considered as a promising source for the development of putative antiplasmodial drugs

Chemical composition and anticandidal properties of the essential oil isolated from aerial parts of Cotula cinerea : a rare and threatened medicinal plant in Morocco

The chemical composition and anticandidal properties of the essential oil of Moroccan Cotula cinerea aerial parts have been examined. GC-MS data were used to identify 24 constituents. Oxygenated monoterpenes constituted the main fraction with trans-thujone (41.4%), cis-verbenyl acetate (24.7%), 1,8-cineole (8.2%) and camphor (5.5%) as the major components. The anticandidal activity of the essential oil was evaluated using a panel of human pathogenic fungi (Candida albicans CCMM L4 and CCMM L5, C. krusei CCMM L10, C. glabrata CCMM L7 and C. parapsilosis CCMM L18). The oil showed high anticandidal activity against all investigated strains with minimal inhibitory concentrations of 3.2 to 4.7 mg/mL depending on the tested yeast and 5.9 mg/mL as a minimal candidicidal concentration value. These findings add significant information to the pharmacological activity of Cotula cinerea essential oil, which may present a good alternative to antibiotics for the treatment of resistant strains of Candida

Bioactive metabolites from the leaves of Withania adpressa

Context: Withania (Solanaceae) species are known to be a rich source of withanolides, which have shown several biological properties. Objective: To identify the compounds responsible for Withania adpressa Coss. antioxidant activity and further test them for their NF-κB inhibition and antiproliferative activity in multiple myeloma cells. Materials and methods: Compounds were obtained from the EtOAc extract of W. adpressa leaves. Structure elucidation was carried out mainly by 1D- and 2D-NMR, and mass spectrometry. Isolated compounds were tested in a dose-response for their in vitro NF-κB inhibition and antiproliferative activity in multiple myeloma cells after 5 and 72 h treatment, respectively. Results: The fractionation resulted in the isolation of a new glycowithanolide named wadpressine (5) together with withanolide F, withaferin A, coagulin L, and nicotiflorin. The latter showed a moderate ability to scavenge free radicals in DPPH (IC50 = 35.3 µM) and NO (IC50 = 41.3 µM) assays. Withanolide F and withaferin A exhibited low µM antiproliferative activity against both multiple myeloma cancer stem cells and RPMI 8226 cells. Furthermore, they inhibited NF-κB activity with IC50 values of 1.2 and 0.047 µM, respectively. The other compounds showed a moderate inhibition of cell proliferation in RPMI 8226 cells, but were inactive against cancer stem cells and did not inhibit NF-κB activity. Discussion and conclusions: One new glycowithanolide and four known compounds were isolated. Biological evaluation data gave further insight on the antitumor potential of withanolides for refractory cancers

The Evaluation of Vascular Endothelial Growth Factor A (VEGFA) and VEGFR2 Receptor as Prognostic Biomarkers in Bladder Cancer

Vascular endothelial growth factor (VEGF) and its receptors (VEGFR1 and VEGFR2) are the most important tissue factors involved in tumor growth and angiogenesis. The aim of this study was to evaluate the promoter mutational status of VEGFA and the expression levels of VEGFA, VEGFR1, and VEGFR2 in bladder cancer (BC) tissues and to correlate the results with the clinical–pathological parameters of BC patients. A total of 70 BC patients were recruited at the Urology Department of the Mohammed V Military Training Hospital in Rabat, Morocco. Sanger sequencing was performed to investigate the mutational status of VEGFA, and RT-QPCR was used to evaluate the expression levels of VEGFA, VEGFR1, and VEGFR2. Sequencing of the VEGFA gene promoter revealed the presence of −460T/C, −2578C/A, and −2549I/D polymorphisms, and statistical analyses showed a significant correlation between −460T/C SNP and smoking (p = 0.02). VEGFA and VEGFR2 expressions were significantly up-regulated in patients with NMIBC (p = 0.003) and MIBC (p = 0.03), respectively. Kaplan–Meier analyses showed that patients with high VEGFA expression had significantly longer disease-free survival (p = 0.014) and overall survival (p = 0.009). This study was very informative, showing the implication of VEGF alterations in BC, suggesting that VEGFA and VEGFR2 expressions could be promising biomarkers for the better management of BC

Exploring urine sediments as a non-invasive method for DNA methylation detection in bladder cancer

Abstract Background The main epigenetic event occurring during the bladder carcinogenesis process is DNA methylation, affecting genes involved in various metabolic pathways and cell regulation. The use of biological fluids such as urine sediments could be used as a non-invasive approach to enhance bladder cancer management. In this study, we aim to determine the promoter methylation status of a panel of genes in bladder cancer on tumor biopsies and urine sediments to evaluate the usefulness of urine samples as a non-invasive approach for methylation status assessment. Methods Using the methylation-specific PCR technique, we explored the promoter methylation status of hTERT, TWIST1, VIM and NID2 genes in 40 tumor biopsies and their paired urine samples from Moroccan bladder cancer patients. Results In this study, bladder tumors showed promoter hypermethylation frequency of individual genes as 90%, 85%, 62.5% and 72.5% in TWIST1, hTERT, NID2 and VIM genes, respectively. Interestingly, the specificity of methylation detection in urine samples was 100% and the sensitivity to detect hypermethylation of TWIST1, hTERT, NID2 and VIM genes reached 91.7%; 97.1%; 84% and 82.8%, respectively. Conclusions Our results clearly show that the assessment of promoter hypermethylation in urine samples is highly specific and has high sensitivity. Furthermore, urine sediments would be a useful approach to detect the DNA methylation status of genes and its potential association with bladder cancer development