SARS-CoV-2 genomic surveillance in Rwanda: Introductions and local transmission of the B.1.617.2 (Delta) variant of concern

The emergence of the SARS-CoV-2 Delta variant of concern (lineage B.1.617.2) in late 2020 resulted in a new wave of infections in many countries across the world, where it often became the dominant lineage in a relatively short amount of time. We here report on a novel genomic surveillance effort in Rwanda in the time period from June to September 2021, leading to 201 SARS-CoV-2 genomes being generated, the majority of which were identified as the Delta variant of concern. We show that in Rwanda, the Delta variant almost completely replaced the previously dominant A.23.1 and B.1.351 (Beta) lineages in a matter of weeks, and led to a tripling of the total number of COVID-19 infections and COVID-19-related fatalities over the course of only three months. We estimate that Delta in Rwanda had an average growth rate advantage of 0.034 (95% CI 0.025-0.045) per day over A.23.1, and of 0.022 (95% CI 0.012-0.032) over B.1.351. Phylogenetic analysis reveals the presence of at least seven local Delta transmission clusters, with two of these clusters occurring close to the border with the Democratic Republic of the Congo, and another cluster close to the border with Tanzania. A smaller Delta cluster of infections also appeared close to the border with Uganda, illustrating the importance of monitoring cross-border traffic to limit the spread between Rwanda and its neighboring countries. We discuss our findings against a background of increased vaccination efforts in Rwanda, and also discuss a number of breakthrough infections identified during our study. Concluding, our study has added an important collection of data to the available genomes for the Eastern Africa region, with the number of Delta infections close to the border with neighboring countries highlighting the need to further strengthen genomic surveillance in the region to obtain a better understanding of the impact of border crossings on lowering the epidemic curve in Rwanda.

Modeling the interactions between MC2R and ACTH models from human.

Melanocortin system is composed of four peptide hormones namely α-, ß-, -γ, and adrenocorticotropic hormone (ACTH), derived from post-translational cleavage of a polypeptide precursor 'proopiomelanocortin (POMC).' Among these hormones, ACTH, a 38 amino acid residue peptide fragment is an important hormone as it is involved in steroid secretion. In addition to this, to cite a few, this hormone is also known to induce variety of other effects, such as alterations in motor/sexual behavior, improvement in memory, and anti-inflammatory effects. To date, five melanocortin receptors (MC1R-MC5R) have been characterized with tissue-specific expression patterns and different binding affinities for each of the melanocortin hormones to regulate various biological functions. In the present work, three-dimensional (3D) models of MC2R and ACTH from human have been predicted, followed by docking and molecular dynamics simulation. While the 3D model of MC2R receptor has been predicted through threading approach, structure of ACTH was built based on ab initio technique. The MC2R model was later successfully docked onto the ACTH structure. Molecular dynamics (MD) simulation for 20 ns was used to compute the binding free energy of MC2R with ACTH model under implicit solvent conditions.

Enhanced H2 gas production from bagasse using adhE inactivated Klebsiella oxytoca HP1 by sequential dark-photo fermentations.

Sequential dark-photo fermentations (SDPF) was used for hydrogen production from bagasse, an acetaldehyde dehydrogenase (adhE) gene inactivated Klebsiella oxytoca HP1 (DeltaadhE HP1) mutant was used to reduce the alcohol content in dark fermentation (DF) broths and to further enhance the hydrogen yield during the photo fermentation (PF) stage. Compared with that of the wild strain, the ethanol concentration in DF broths of DeltaadhE HP1 decreased 69.4%, which resulted in a hydrogen yield in the PF stage and the total hydrogen yield over the two steps increased by 54.7% and 23.5%, respectively. The culture conditions for hydrogen production from acid pretreated bagasse by SDPF were optimized as culture temperature 37.5 degrees C, initial pH 7.0, and cellulase loading 20 FPA/g in the DF stage, with initial pH 6.5, temperature 30 degrees C and photo intensity 5,000 lux in the PF stage. Under optimum conditions, by using DeltaadhE HP1 and wild type strain, the H(2) yields were 107.8+/-5.3 mL H(2)/g-bagasse, 96.2+/-4.4 mL H(2)/g-bagasse in DF and 54.3+/-2.2 mL H(2)/g-bagasse, 35.1+/-2.0 mL H(2)/g-bagasse in PF, respectively. The special hydrogen production rate (SHPR) were 5.51+/-0.34 mL H(2)/g-bagasseh, 4.95+/-0.22 mL H(2)/g-bagasseh in DF and 0.93+/-0.12 mL H(2)/g-bagasseh, 0.59+/-0.07 mL H(2)/g-bagasseh in PF, respectively. The total hydrogen yield from bagasse over two steps was 162.1+/-7.5 mL H(2)/g-bagasse by using DeltaadhE HP1, which was 50.4% higher than that from dark fermentation only. These results indicate that reducing ethanol content during dark fermentation by using an adhE inactivated strain can significantly enhance hydrogen production from bagasse in the SDPF system. This work also proved that SDPF was an effective way to improve hydrogen production from bagasse.