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Clinical trials previously demonstrated the notable capacity to elicit visual percepts in individuals with visual impairments caused by retinal diseases by electrically stimulating the remaining neurons on the retina. However, these implants restored very limited visual acuity and required transcutaneous cables traversing the eyeball, leading to reduced reliability and complex surgery with high postoperative infection risks. To overcome the limitations imposed by cables, a retinal implant architecture in which near-infrared illumination carries both power and data through the pupil to a digital stimulation controller is presented. A high efficiency multi-junction photovoltaic cell transduces the optical power to a CMOS stimulator capable of delivering flexible interleaved sequential stimulation through a diamond microelectrode array. To demonstrate the capacity to elicit a neural response with this approach while complying with the optical irradiance limit at the pupil, fluorescence imaging with a calcium indicator is used on a degenerate rat retina. The power delivered by the laser at the permissible irradiance of 4 mW/mm2 at 850 nm is shown to be sufficient to both power the stimulator ASIC and elicit a response in retinal ganglion cells (RGCs), with the ability to generate of up to 35 000 pulses per second at the average stimulation threshold. This confirms the feasibility of generating a response in RGCs with an infrared-powered digital architecture capable of delivering complex sequential stimulation patterns at high repetition rates, albeit with some limitations.

The Lobo reservoir, designed to supply water to the Daloa city population (central west of Côte d’Ivoire), is facing the phenomenon of eutrophication due to the agricultural plots located upstream of the reservoir inputs. Studies have highlighted the reservoir pollution and sedimentation problems. This study was initiated to test the effectiveness of a transfer model in the fight against the eutrophication problem. The objective of this study was to determine the optimal width of a vegetative filter strip on the banks of the Lobo reservoir, where the water intake installations of the drunk water company SODECI are located, using the VFSMOD model. The methodological approach is structured into four (4) main stages: 1—Evaluation of runoff from the source of pollution (contributing surface) during a rainy episode; 2—Calculation of the incoming runoff volume and the sediment load; 3—Simulation of runoff reduction and incoming sediments within the grassy filter strip; and 4—Determination of the optimal width of the grassy strip. The results obtained showed a contributing source area of 13.5 ha and 2% as the average slope. A runoff volume of 4680 m3 coming from the source of pollution is reduced by 1119 m3 (24%) through a grassy strip that is 3 m wide. The sediment load goes from 132 kg to 33 kg, a reduction of 75% in the quantity of sediment entering. The scenarios tested showed that a grassy strip width equal to 3 m should allow for a reduction of 75% of upstream sediments. This grassy strip width of 3 m should be considered for implementing a vegetative filter strip around the Lobo reservoir.

OaPAC is a recently discovered blue-light-using flavin adenosine dinucleotide (BLUF) photoactivated adenylate cyclase from the cyanobacterium Oscillatoria acuminata that uses adenosine triphosphate and translates the light signal into the production of cyclic adenosine monophosphate. Here, we report crystal structures of the enzyme in the absence of its natural substrate determined from room-temperature serial crystallography data collected at both an X-ray free-electron laser and a synchrotron, and we compare these structures with cryo-macromolecular crystallography structures obtained at a synchrotron by us and others. These results reveal slight differences in the structure of the enzyme due to data collection at different temperatures and X-ray sources. We further investigate the effect of the Y6W mutation in the BLUF domain, a mutation which results in a rearrangement of the hydrogen-bond network around the flavin and a notable rotation of the side chain of the critical Gln48 residue. These studies pave the way for picosecond–millisecond time-resolved serial crystallography experiments at X-ray free-electron lasers and synchrotrons in order to determine the early structural intermediates and correlate them with the well studied picosecond–millisecond spectroscopic intermediates.

IntroductionResponse to public health emergencies is a big challenge in African countries due to inadequate workforce. Integrated Disease Surveillance and Response (IDSR) is a strategy implemented by African member states of WHO to strengthen capacity for disease surveillance and response at all levels. Despite successful implementation of IDSR in most countries, one of the challenges that persists is that of inadequate trained workforce competent enough for public health surveillance. Introducing IDSR pre-service curriculum in public health training institutions has therefore been recommended by WHO as one of the strategies to sustainably address the human resource challenge. We report on the process and lessons learnt in Sierra Leone which was the first country to implement the recommendation.MethodsThis was a descriptive study where the process of introducing and implementing IDSR pre-service curriculum in Sierra Leone was documented from 2018 to 2024. Data was collected through observation, documentation and analysis of key processes that took place. These processes included, inter alia, advocacy with public health training institutions, development of the IDSR pre-service curriculum and incorporation of the curriculum into the existing training programs of colleges and universities.ResultsIDSR preservice curriculum was developed and successfully introduced in eight targeted public health training institutions in Sierra Leone from September 2021. Training content was adapted from the 3rd Edition of IDSR technical guidelines developed by WHO in 2019. As at February 2024, more than 4,200 students had started taking IDSR modules in the eight institutions with 2,108 having completed and graduated. During the process, we learned that key enablers to success were government support, good advocacy with the training institutions and training of lecturers on IDSR. Main challenges were the long process of curriculum approval by training institutions and handling of big classes of students without adequate training materials.ConclusionIntroducing IDSR into the preservice curricula of public health training institutions is feasible and can provide a reliable and continuous supply of a trained workforce ready to be utilized for IDSR in Africa. Successful implementation requires advocacy with training institutions as well as regular monitoring of the implementation to maintain good quality.

Abstract The main protease (Mpro) of SARS-CoV-2 is critical for viral function and a key drug target. Mpro is only active when reduced; turnover ceases upon oxidation but is restored by re-reduction. This suggests the system has evolved to survive periods in an oxidative environment, but the mechanism of this protection has not been confirmed. Here, we report a crystal structure of oxidized Mpro showing a disulfide bond between the active site cysteine, C145, and a distal cysteine, C117. Previous work proposed this disulfide provides the mechanism of protection from irreversible oxidation. Mpro forms an obligate homodimer, and the C117-C145 structure shows disruption of interactions bridging the dimer interface, implying a correlation between oxidation and dimerization. We confirm dimer stability is weakened in solution upon oxidation. Finally, we observe the protein’s crystallization behavior is linked to its redox state. Oxidized Mpro spontaneously forms a distinct, more loosely packed lattice. Seeding with crystals of this lattice yields a structure with an oxidation pattern incorporating one cysteine-lysine-cysteine (SONOS) and two lysine-cysteine (NOS) bridges. These structures further our understanding of the oxidative regulation of Mpro and the crystallization conditions necessary to study this structurally.

Objectives Our research adopts computational techniques to analyze disease outbreaks weekly over a large geographic area while maintaining local-level analysis by incorporating relevant high-spatial resolution cultural and environmental datasets. The abundance of data about disease outbreaks gives scientists an excellent opportunity to uncover patterns in disease spread and make future predictions. However, data over a sizeable geographic area quickly outpace human cognition. Our study area covers a significant portion of the African continent (about 17,885,000 km 2 ). The data size makes computational analysis vital to assist human decision-makers. Methods We first applied global and local spatial autocorrelation for malaria, cholera, meningitis, and yellow fever case counts. We then used machine learning to predict the weekly presence of these diseases in the second-level administrative district. Lastly, we used machine learning feature importance methods on the variables that affect spread. Results Our spatial autocorrelation results show that geographic nearness is critical but varies in effect and space. Moreover, we identified many interesting hot and cold spots and spatial outliers. The machine learning model infers a binary class of cases or none with the best F 1 score of 0.96 for malaria. Machine learning feature importance uncovered critical cultural and environmental factors affecting outbreaks and variations between diseases. Conclusions Our study shows that data analytics and machine learning are vital to understanding and monitoring disease outbreaks locally across vast areas. The speed at which these methods produce insights can be critical during epidemics and emergencies.

Abstract X-ray Free Electron Lasers (XFEL) are cutting-edge pulsed x-ray sources, whose extraordinary pulse parameters promise to unlock unique applications. Several new methods have been developed at XFELs; however, no methods are known, which allow ab initio atomic level structure determination using only a single XFEL pulse. Here, we present experimental results, demonstrating the determination of the 3D atomic structure from data obtained during a single 25 fs XFEL pulse. Parallel measurement of hundreds of Bragg reflections was done by collecting Kossel line patterns of GaAs and GaP. To the best of our knowledge with these measurements, we reached the ultimate temporal limit of the x-ray structure solution possible today. These measurements open the way for obtaining crystalline structures during non-repeatable fast processes, such as structural transformations. For example, the atomic structure of matter at extremely non-ambient conditions or transient structures formed in irreversible physical, chemical, or biological processes may be captured in a single shot measurement during the transformation. It would also facilitate time resolved pump-probe structural studies making them significantly shorter than traditional serial crystallography.

Climate variability has had major health consequences for both humans and animals. A cross-sectional study was conducted in six administrative regions of The Gambia to respond to three questions: (i) what are the livestock farmers’ perceived occurrences and causes of climate variability? (ii) what are the perceived impacts of climate variability on livestock farming? (iii) what factors influence livestock farmers’ knowledge and perception of the causes and impact of climate variability? A total of 440 livestock farmers comprising 351 (80%) males and 89 (20%) females were interviewed and 6 Focus Group Discussions were held. The data were analysed using descriptive statistics, Pearson's chi-squares test and Binary logistic regression. Livestock farmers are aware of the causes and effects of climate variability on their productivity. Climate variability caused cattle farmers to have production issues, and as a result, this investigation also reveals the impact on their productivity. Finally, the result also shows that the explanatory variables (age and region of residence) were the main factors significantly influencing livestock farmers’ perception of climate variability. There is need for the government of The Gambia to address the challenges faced by livestock farmers due to climate variability.

X-ray free-electron lasers (XFELs) can probe chemical and biological reactions as they unfold with unprecedented spatial and temporal resolution. A principal challenge in this pursuit involves the delivery of samples to the X-ray interaction point in such a way that produces data of the highest possible quality and with maximal efficiency. This is hampered by intrinsic constraints posed by the light source and operation within a beamline environment. For liquid samples, the solution typically involves some form of high-speed liquid jet, capable of keeping up with the rate of X-ray pulses. However, conventional jets are not ideal because of radiation-induced explosions of the jet, as well as their cylindrical geometry combined with the X-ray pointing instability of many beamlines which causes the interaction volume to differ for every pulse. This complicates data analysis and contributes to measurement errors. An alternative geometry is a liquid sheet jet which, with its constant thickness over large areas, eliminates the problems related to X-ray pointing. Since liquid sheets can be made very thin, the radiation-induced explosion is reduced, boosting their stability. These are especially attractive for experiments which benefit from small interaction volumes such as fluctuation X-ray scattering and several types of spectroscopy. Although their use has increased for soft X-ray applications in recent years, there has not yet been wide-scale adoption at XFELs. Here, gas-accelerated liquid sheet jet sample injection is demonstrated at the European XFEL SPB/SFX nano focus beamline. Its performance relative to a conventional liquid jet is evaluated and superior performance across several key factors has been found. This includes a thickness profile ranging from hundreds of nanometres to 60 nm, a fourfold increase in background stability and favorable radiation-induced explosion dynamics at high repetition rates up to 1.13 MHz. Its minute thickness also suggests that ultrafast single-particle solution scattering is a possibility.

Serial femtosecond crystallography (SFX) is a powerful technique that exploits X-ray free-electron lasers to determine the structure of macro-molecules at room temperature. Despite the impressive exposition of structural details with this novel crystallographic approach, the methods currently available to introduce crystals into the path of the X-ray beam sometimes exhibit serious drawbacks. Samples requiring liquid injection of crystal slurries consume large quantities of crystals (at times up to a gram of protein per data set), may not be compatible with vacuum configurations on beamlines or provide a high background due to additional sheathing liquids present during the injection. Proposed and characterized here is the use of an immiscible inert oil phase to supplement the flow of sample in a hybrid microfluidic 3D-printed co-flow device. Co-flow generation is reported with sample and oil phases flowing in parallel, resulting in stable injection conditions for two different resin materials experimentally. A numerical model is presented that adequately predicts these flow-rate conditions. The co-flow generating devices reduce crystal clogging effects, have the potential to conserve protein crystal samples up to 95% and will allow degradation-free light-induced time-resolved SFX.

Abstract Background Research evidence is needed to strengthen capacities in emergency preparedness and response (EPR). However, the absence of a clear research agenda limits the optimal use of research evidence. This paper reports on the prioritization of research questions and topics that could contribute to evidence-informed strengthening of EPR capacities in the African region. Methods The priority-setting consisted of desk review and stakeholder consultation workshop. Twenty-nine people participated in the workshop, including representatives from WHO regional office and EPR focal points in Africa, representatives of research institutions, and partners from Science for Africa Foundation, United Nations Children's Fund and Africa Center for Disease Control. Modified Delphi technique was used to systematically arrive at specific and cross-cutting research priorities in the three broad areas of the EPR, which are program Implementation, Clinical and Epidemiology. The research questions/topics were ranked on five-point Likert scale (1 = very low to 5 = very high) based on seven agreed-on criteria. Research priority score was calculated for each question as the mean of the criteria scores. Results A total of 123 research questions comprising, 29 on Epidemiology, 22 on Clinical, 23 on program Implementation, and 49 on cross-cutting issues were ranked. The top ten research priorities were: knowledge and skills of healthcare workers in detecting and responding effectively to disease outbreaks; quality of data (accuracy, timeliness, completeness) for epidemic prone diseases; determinants of vaccine hesitancy; determinants of infection transmission among health care workers during PHE; effective measures for protecting health workers from highly infectious pathogens in PHE; strategies to improve the effectiveness of contact tracing for epidemic prone diseases; effectiveness of current case definitions as screening tools for epidemic and pandemic prone diseases; measures to strengthen national and sub-national laboratory capacity for timely disease confirmation within the Integrated Diseases Surveillance and Response framework; factors affecting prompt data sharing on epidemic-prone diseases; and effective strategies for appropriate community participation in EPR. Conclusions The collaborative multi-stakeholder workshop produced a starting list of priority research questions and topics for strengthening EPR capacities in Africa. Action needs to be taken to continuously update the research agenda and support member States to contextualize the research priorities and commission research for timely generation and uptake of evidence.

Abstract Climate change causes extreme conditions like prolonged drought, which results in yield reductions due to its effects on nutrient balances such as nitrogen uptake and utilization by plants. Nitrogen (N) is a crucial nutrient element for plant growth and productivity. Understanding the mechanistic basis of nitrogen use efficiency (NUE) under drought conditions is essential to improve wheat (Triticum aestivum L.) yield. Here, we evaluated the genetic variation of NUE‐related traits and photosynthesis response in a diversity panel of 200 wheat genotypes under drought and nitrogen stress conditions to uncover the inherent genetic variation and identify quantitative trait loci (QTLs) underlying these traits. The results revealed significant genetic variations among the genotypes in response to drought stress and nitrogen deprivation. Drought impacted plant performance more than N deprivation due to its effect on water and nutrient uptake. GWAS identified a total of 27 QTLs with a significant main effect on the drought‐related traits, while 10 QTLs were strongly associated with the NUE traits. Haplotype analysis revealed two different haplotype blocks within the associated region on chromosomes 1B and 5A. The two haplotypes showed contrasting effects on N uptake and use efficiency traits. The in silico and transcript analyses implicated candidate gene coding for cold shock protein. This gene was the most highly expressed gene under several stress conditions, including drought stress. Upon validation, these QTLs on 1B and 5A could be used as a diagnostic marker for NUE and drought tolerance screening in wheat.

Abstract Glossina species are known to transmit African Trypanosomiasis, one of the most important infectious diseases for both livestock and humans in sub-Saharan Africa. Therefore, the aim of this study was to characterize trapped Glossina spp. from The Gambia using morphological and molecular techniques in relation to the vegetation cover types. A line transect survey was carried out in all the administrative regions of The Gambia. Tsetse fly trapping was carried out for 14 days during each season using line transect. A total of 220 Glossina spp. specimens (117 F and 103 M) were captured, and DNA was extracted from the legs of 100 randomly selected Glossina spp. Further, DNA samples were tested by a conventional PCR assay. A total of 135/220 (61%; 95% CI: 54.6-67.8%) and 85/220 (39%; 95% CI: 32.2-45.4%) flies were identified as Glossina morsitans submorsitans and Glossina palpalis gambiensis, respectively, with most caught during wet season (53.6%) and more females (53.2%) than males. Results of the morphological identification agreed with those of molecular identification. The type of vegetation cover significantly influenced the caught of tsetse flies. Animals and humans at the various trapping sites are at risk of being bitten by tsetse flies.

In Côte d’Ivoire, mango fruit plays an important economic role as the third major exported fruit after banana and pineapple. Despite this economic importance, fungal diseases are one of the main issues in the mango value chain with Colletotrichum gloeosporioides causing total postharvest losses estimated up to 20%. The aim of this study was to evaluate the antifungal activity of yeasts, lactic acid bacteria and Bacillus strains isolated from fermented mango fruits as potential biocontrol agents of Colletotrichum gloeosporioides. First, C. gloeosporioides was isolated from contaminated mangoes on potato agar medium, while fermented mangoes were used to isolate yeasts, Bacillus and lactic acid bacteria on DRBC, nutrient and MRS agar, respectively. Afterwards, the in vitro antifungal activity of yeasts, Bacillus and lactic acid bacteria against C. gloeosporioides was tested using dual culture and diffusion methods. The total isolates bateria and yeasts from fermented mango were: 238 yeasts, 214 Bacillus and 252 lactic acid bacteria. The results of antifungal activity of isolated bacteria and yeasts against C. gloeosporioides were as follows: 78 yeasts isolates (33%) were able to inhibit C. gloeosporioides with 11% inhibition more than 40% mycelial growth. The Bacillus isolates were less active (28% inhibition) of C. gloeosporioides with 2% inhibition greater than 60%. As for lactic acid bacteria, they were more active since 58% of isolates showed antifungal activity with 23% of which showed inhibition greater than 60%. Based on the results lactic acid bacteria isolated from fermented mangoes can be used as valuable starters for anthracnose biocontrol.

Background: The World Health Organisation (WHO) Regional Office for Africa (AFRO) has developed a comprehensive capacity development programme to support the successful implementation of the Integrated Disease Surveillance and Response 3rd edition Technical Guidelines (IDSR). As part of the learning program, a series of asynchronous online courses are offered on OpenWHO in English, French and Portuguese. This paper describes the use of five IDSR online courses and reports on feedback received from learners on Course 1 in the English series. Methods: An online learner survey was developed, and a descriptive analysis was conducted. This paper also reports on use related empirical metadata from the OpenWHO platform. Results: Overall, learners (97%-n/N) of Course 1 IDSR English series indicated a positive perception toward their online learning experience because of the quality of course content, its organization, ease of use and relevance to their workplace needs. In addition, 88% (n/N) of learners reported that they had used their acquired knowledge at least sometimes and 54.4% (n/N) had shared their learning with others. Lastly, the quiz analyses showed an average of right answers of 78.97% for quiz 1 and 69.94% for quiz 2. Conclusion: Online learning is an essential component of a blended capacity development programme and provides cost effective, equitable and impactful learning. Learners who have a learning goal and find their needs met in courses tend to show more satisfaction and motivation to share their learning.

The JUNGFRAU detector is a well-established hybrid pixel detector developed at the Paul Scherrer Institut (PSI) designed for free-electron laser (FEL) applications. JUNGFRAU features a charge-integrating dynamic gain switching architecture, with three different gain stages and 75 μm pixel pitch. It is widely used at the European X-ray Free-Electron Laser (EuXFEL), a facility which produces high brilliance X-ray pulses at MHz repetition rate in the form of bursts repeating at 10 Hz. In nominal configuration, the detector utilizes only a single memory cell and supports data acquisition up to 2 kHz. This constrains the operation of the detector to a 10 Hz frame rate when combined with the pulsed train structure of the EuXFEL. When configured in so-called burst mode, the JUNGFRAU detector can acquire a series of images into sixteen memory cells at a maximum rate of around 150 kHz. This acquisition scheme is better suited for the time structure of the X-rays as well as the pump laser pulses at the EuXFEL. To ensure confidence in the use of the burst mode at EuXFEL, a wide range of measurements have been performed to characterize the detector, especially to validate the detector alibration procedures. In particular, by analyzing the detector response to varying photon intensity (so called ‘intensity scan’), special attention was given to the characterization of the transitions between gain stages. The detector was operated in both dynamic gain switching and fixed gain modes. Results of these measurements indicate difficulties in the characterization of the detector dynamic gain switching response while operated in burst mode, while no major issues have been found with fixed gain operation. Based on this outcome, fixed gain operation mode with all the memory cells was used during two experiments at EuXFEL, namely in serial femtosecond protein crystallography and Kossel lines measurements. The positive outcome of these two experiments validates the good results previously obtained, and opens the possibility for a wider usage of the detector in burst operation mode, although compromises are needed on the dynamic range.

New agroecological practices propose to manage soil fertility using soil microorganisms such as arbuscular mycorrhizal fungi (AMF). However, few studies have been conducted on the impact of plantain mycorrhization and metal (Fe2+ and Al3+) solubilisation in soil. This study evaluates the effectiveness of native AMF on plantain growth and metal leaching from soil. Trap plants (maize, sorghum and cowpea) were grown to produce various inoculums. Then, plantains were grown under controlled conditions, with six treatments (control, plantain without inoculum, plantain with maize root inoculum, vigna root inoculum, sorghum root inoculum and mixed root inoculum) replicated five times. Growth parameters were measured, and the rate of plantain root colonization was evaluated by determining the frequency or intensity of infection. The contents of metals in leached solutions were analyzed using ICP-OES. Results indicated the rate of plantain roots colonization by fungi was not significantly different between the different treatments. Plantain biomass remained very low whatever the treatment. However, plant inoculated with vigna roots inoculum had the highest biomass while plant inoculated with sorghum root inoculum showed the lowest biomass. Leached solutions from soils with inoculated plants had on average a pH value of one pH unit lower than leached solutions from soils without inoculum. In addition, plantain mycorrhization can promote the leaching of Fe2+ from the soil by acidification, whereas the difference between treatments was not significant for the concentration of Al3+ in solutions. These results suggest that the association of plantain with microorganisms remains a way for agroecological banana production in Côte d’Ivoire.

La question du management et de la motivation d’entreprise se trouve au centre de nombreuses recherches sur la gestion de la variable humaine au travail. Ainsi cette étude qui s’inscrit dans la même thématique traite du lien entre le style de management et la motivation des femmes au travail. La méthode utilisée pour répondre à cette préoccupation comporte un questionnaire incluant une échelle de motivation au travail. Les résultats montrent que les femmes soumises à un style de management participatif sont plus motivées que celles soumises à un style de management autoritaire.

Since 2008, the quantity and size of silky shark, Carcharhinus falciformis decrease drastically in catches of artisanal driftnet fishery operating in the coastal waters off Côte d’Ivoire. The objective of this study was to describe the reproductive biology of this species, based on 336 specimens (162 males and 174 females). The total length (TL) of males and female ranged from 81–242 and 79–254 cm respectively. The sex ratio was 0.89:1 (M:F) and 0.93:1 (M:F) in embryos and adults respectively. Males of >180 cm had calcified clasper (17–35 cm) whereas females of >190 cm had oviduct gland length of 18–47 mm. The estimated length at first maturity was 182.8 cm for males and 195.2 cm for females. The range in litter size of three gravid females was 7–9, with an average of 8 embryos of 52–54.5 cm TL were collected in August and December. However, the absence of neonates and scars on females' body, as well as ovulating and differentiating females in catches does not allow a clear determination of its reproductive period in Ivorian waters and therefore, additional research including histological analysis is necessary to better understand the process of spawning of silky shark.

The African Region reports the heaviest burden of public health emergencies globally. This paper presents an exploratory analysis of public health events data collected the past 22 years in the WHO Africa region, to explore patterns and trends that can inform public health strategies, policy changes and develop appropriate tools to improve disease surveillance, preparedness and response to public health emergencies. A suite of exploratory data analysis methods combining time series analysis, summary statistics, temporal visualisations, geographic information system (GIS) mapping, trend analysis and statistical tests were used to derive patterns and trends from the data. An in-depth analysis of zoonotic disease outbreaks by geography and time was explored. The analysis also focused on whether these outbreaks were viral haemorrhagic related or had other characteristics. Results reveal that between 2001 and 2022, a total of 2234 public health events have been recorded in the WHO African Region of which 1886 events (84.4%) were substantiated. The paper confirms an average of 102 public health events reported yearly during the last 22 years time frame. The large majority (92%) of the substantiated events were infectious diseases (n=1730), 30% (n=566) are zoonoses and 5% (n=95) are humanitarian crises such as disaster events and conflicts. The number of zoonotic disease outbreaks has significantly increased (by 87%) between the past two decades, from 2003 to 2012 period (M=18.6, SD=4.8) and 2013–2022 period (M=34.7, SD=14); t(18) = 3.4, p=0.0032. This analysis shows growing challenges faced in the Africa region every year. One-health approach and its coordination across multiple sectors, disciplines and communities is critical to achieve the objectives.

The Dictyostelium discoideum dye-decolorizing peroxidase (DdDyP) is a newly discovered peroxidase, which belongs to a unique class of heme peroxidase family that lacks homology to the known members of plant peroxidase superfamily. DdDyP catalyzes the H2O2-dependent oxidation of a wide-spectrum of substrates ranging from polycyclic dyes to lignin biomass, holding promise for potential industrial and biotechnological applications. To study the molecular mechanism of DdDyP, highly pure and functional protein with a natively incorporated heme is required, however, obtaining a functional DyP-type peroxidase with a natively bound heme is challenging and often requires addition of expensive biosynthesis precursors. Alternatively, a heme in vitro reconstitution approach followed by a chromatographic purification step to remove the excess heme is often used. Here, we show that expressing the DdDyP peroxidase in ×2 YT enriched medium at low temperature (20°C), without adding heme supplement or biosynthetic precursors, allows for a correct native incorporation of heme into the apo-protein, giving rise to a stable protein with a strong Soret peak at 402 nm. Further, we crystallized and determined the native structure of DdDyP at a resolution of 1.95 Å, which verifies the correct heme binding and its geometry. The structural analysis also reveals a binding of two water molecules at the distal site of heme plane bridging the catalytic residues (Arg239 and Asp149) of the GXXDG motif to the heme-Fe(III) via hydrogen bonds. Our results provide new insights into the geometry of native DdDyP active site and its implication on DyP catalysis.

The growing understanding that soil bacteria play a critical role in ecosystem servicing has led to a number of large-scale biogeographical surveys of soil microbial diversity. However, most of such studies have focused on northern hemisphere regions and little is known of either the detailed structure or function of soil microbiomes of sub-Saharan African countries. In this paper, we report the use of high-throughput amplicon sequencing analyses to investigate the biogeography of soil bacteria in soils of Côte d’Ivoire. 45 surface soil samples were collected from Côte d’Ivoire, representing all major biomes, and bacterial community composition was assessed by targeting the V4-V5 hypervariable region of the 16S ribosomal RNA gene. Causative relationships of both soil physicochemical properties and climatic data on bacterial community structure were infered. 48 phyla, 92 classes, 152 orders, 356 families, and 1,234 genera of bacteria were identified. The core bacteriobiome consisted of 10 genera ranked in the following order of total abundance: Gp6, Gaiella, Spartobacteria_genera_incertae_sedis, WPS-1_genera_incertae_sedis, Gp4, Rhodoplanes, Pseudorhodoplanes, Bradyrhizobium, Subdivision3_genera_incertae_sedis, and Gp3. Some of these genera, including Gp4 and WPS-1_genera_incertae_sedis, were unequally distributed between forest and savannah areas while other taxa (Bradyrhizobium and Rhodoplanes) were consistently found in all biomes. The distribution of the core genera, together with the 10 major phyla, was influenced by several environmental factors, including latitude, pH, Al and K. The main pattern of distribution that was observed for the core bacteriobiome was the vegetation-independent distribution scheme. In terms of predicted functions, all core bacterial taxa were involved in assimilatory sulfate reduction, while atmospheric dinitrogen (N2) reduction was only associated with the genus Bradyrhizobium. This work, which is one of the first such study to be undertaken at this scale in Côte d’Ivoire, provides insights into the distribution of bacterial taxa in Côte d’Ivoire soils, and the findings may serve as biological indicator for land management in Côte d’Ivoire.

Three natural phenolic compounds are found to bind to an allosteric site in SARS-CoV-2 papain-like protease and exhibit antiviral activity in vitro, showing potential as starting scaffolds for drug design.