The mutualistic symbiosis between fungus‐growing termites and Termitomyces fungi originated in Africa and shows a moderate degree of interaction specificity. Here we estimate the age of the mutualism ...and test the hypothesis that the major splits have occurred simultaneously in the host and in the symbiont. We present a scenario where fungus‐growing termites originated in the African rainforest just before the expansion of the savanna, about 31 Ma (19–49 Ma). Whereas rough age correspondence is observed for the four main clades of host and symbiont, the analysis reveals several recent events of host switching followed by dispersal of the symbiont throughout large areas and throughout different host genera. The most spectacular of these is a group of closely related fungi (the maximum age of which is estimated to be 2.4 Ma), shared between the divergent genera Microtermes, Ancistrotermes, Acanthotermes and Synacanthotermes (which diverged at least 16.7 Ma), and found throughout the African continent and on Madagascar. The lack of geographical differentiation of fungal symbionts shows that continuous exchange has occurred between regions and across host species.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
A moderately halophilic and strictly aerobic bacterium was isolated from a human stool as part of a study on the diagnosis of childhood malnutrition in Mali. Strain Marseille-Q1616T is a ...Gram-stain-positive, rod-shaped, catalase-positive and oxidase-negative bacterium. It has a genome size of 3.91 Mbp with 39.79% G+C content, which contains 3954 protein-coding genes including genes encoding phosphomycin resistance and Listeria monocytogenes, 16 rRNA genes and 64 tRNA genes. Strain Marseille-Q1616T exhibited a 96.3% 16S rRNA gene sequence similarity and shared an OrthoANI value of 70.64% (the highest observed) with Virgibacillus kekensis, the phylogenetically closest validly published species. Based on phenotypic and phylogenetic evidence and genomic average nucleotide identity values, we suggest the creation of a new species within the Virgibacillus genus, named Virgibacillus doumboii sp. nov., type strain Marseille-Q1616T (= CSURQ1616).
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Habitat heterogeneity has a complex effect on ant species richness and community structure (both alpha- and beta-diversity). Savannahs and forests are thought to have distinct species assemblages, ...but studies comparing savannah–forest mosaics produced conflicting results, with savannah (the less complex ecosystem) poorer in species, equally rich, or richer than forest (the most complex habitat). We compared subterranean and above ground ant assemblages in savannah and forests of Lamto Reserve (Côte d’Ivoire) to examine how habitat heterogeneity and vertical stratification drive species composition and structure patterns. The Ants of the Leaf Litter (ALL) protocol and soil monolith were used to sample ants along 16 transects of 200 m in the three main habitats (gallery forest, forest islands, and savannah). In total, 138 species from 44 genera were collected. Forested habitats held assemblages that matched those found in savannah in terms of species density and richness; however, they differed in composition. Taxonomic structure varied among habitats, with Formicinae and Amblyoponinae prevailing in savannah, and Myrmicinae numerically dominant in forests. Ants were clearly vertically stratified. Subterranean assemblages had a less even distribution of occurrences among species as compared to above ground ones. The patterns observed agree with the heterogeneity-diversity theory relative to beta-diversity but not alpha-diversity, emphasizing the difficulty to generalize across continents about factors structuring ant assemblages. Our results support the need to conserve both forest and savannah to maintain biodiversity at landscape level in Côte d’Ivoire.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Strain Marseille-Q1234T is a new species from the genus Halobacillus that was isolated in 2019 from a stool sample in a healthy Malian child <5 years old. Cells are Gram-positive and strictly ...halophilic bacilli. Strain Marseille-Q1234T exhibits 98.46% 16S rRNA gene sequence similarity to Halobacillus naozhouensis strain JSM 071068T (NR_116505.1), the phylogenetically closely related species with standing in nomenclature. Based on the phenotypic and phylogenetic evidence, OrthoANI values and results of the biochemical tests, the new species is named Halobacillus ihumii sp. nov., for which strain Marseille-Q1234T (= CSURQ1234) is proposed as the type strain.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Purpose: To investigate the radiation dose reduction and the effect of weighting schemes on image quality in cone‐beam dedicated breast CT acquired with coronal truncated projections that is similar ...in concept as extended field‐of‐view imaging with laterally‐shifted flat‐panel detectors. Methods: Three pre‐weighting schemes were implemented in conjunction with filtered backprojection (FBP) reconstruction to study the effect of coronal truncation in dedicated breast CT. If the fan‐angle of the non‐truncated projections is represented as 2f (24‐degrees), then coronal truncations corresponding to f+0.25, f+1.5, and f+2.7‐degrees were investigated. Monte Carlo simulations using the GEANT4 toolkit were used to determine the radiation dose reduction at the aforementioned truncations. Projection images of a numerical phantom with dimensions representative of an average pendant breast containing six spherical signal objects in a homogenous background were reconstructed without and with truncation. Cone‐beam projections from a diagnostic dedicated breast CT exam acquired with fan‐angle of 2f were truncated at the aforementioned fan‐angles and reconstructed. Phantom and clinical images were analyzed for artifacts and the visibility of signal features. Results: For an average 14‐cm diameter, 15% fibroglandular breast, the estimated dose reduction at fan‐angles of f+0.25, f+1.5, and f+2.7‐degrees were 47%, 34% and 21%, respectively. The severity of artifacts increased with decreasing fan‐angle. The choice of weighting scheme does not appear to have a substantial effect on mitigating artifacts. At fan‐angles of f+1.5 and above, shading artifacts were subtle and could not be easily discerned. The signal objects in the phantom and the microcalcification in the clinical images were discernible. For 10, 14 and 18 cm diameter, 15% fibroglandular breasts, the radiation dose reduction at fan‐angle of f+1.5‐degrees were 27%, 34% and 37%, respectively. Conclusion: There exists a potential to reduce radiation dose by approximately 30% from cone‐beam dedicated breast CT acquired with coronal truncated projections. Supported in part by the National Institutes of Health (NIH) grants R01 CA128906 and R21 CA134128. The contents are solely the responsibility of the authors and do not represent the official views of the NIH or the NCI.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
High salt intake has been linked to several diseases including obesity and an increased risk of death; however, fecal salinity and the ability of salt to alter the gut microbiota, which was recently ...identified as an instrumental factor for health and disease, remains poorly explored.
We analyzed the fecal samples of 1326 human individuals for salinity by refractometry, 572 for gut microbiota by culturomics, and 164 by 16S rRNA-targeted metagenomics. Geographical origin, age, gender, and obesity were tested as predictors of fecal salinity and halophilic diversity. All halophilic isolates were characterized by taxonogenomics and their genome sequenced.
Fecal salinity was associated with obesity independently of geographical origin, gender, and age. The first 2 human-associated halophilic archaeal members were isolated along with 64 distinct halophilic species, including 21 new species and 41 known in the environment but not in humans. No halophiles grow in less than 1.5% salinity. Above this threshold, the richness of the halophilic microbiota was correlated with fecal salinity (r = 0.58, p < 0.0001). 16S metagenomics linked high fecal salinity to decreased diversity (linear regression, p < .035) and a depletion in anti-obesity Akkermansia muciniphila and Bifidobacterium, specifically B. longum and B. adolescentis. Genomics analysis suggested that halophilic microbes are not only transient passengers but may be residents of the human gut.
High salt levels are associated with alteration of the gut microbial ecosystem and halophilic microbiota, as discovered during this study. Further studies should clarify if the gut microbiota alterations associated with high salt levels and the human halophilic microbiota could be causally related to human disease, such as obesity.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Two main types of hollow tree are frequently found in savannas: trees with external splits (externally damaged trees), and trees with no or little visible external damage, but with their entire core ...removed (internally damaged or ‘piped’ trees). As this may affect trunk mechanical resistance and tree survivorship, we studied the incidence of these two types of cavity in relation to two possible causal agents, fire and termites, in a West African savanna. Overall, the proportion of damaged adult trees (height >2 m) reached 36%, and up to 84% for Crossopteryx febrifuga. In this species, almost all (93%) damaged individuals showed signs of digging by fungus-grower and wood-feeder termites. External damage was more frequent in the more fire-prone shrubby savanna, suggesting that while termites are responsible for the piping, fire is responsible for the later opening of the trunk. Trees growing in the more fire-prone savanna tended to reach significantly smaller sizes, both in height and basal diameter, than in the less intensely burnt woody savanna. There was also evidence that piped trees were taller than externally damaged trees. This strongly suggests that fire causes an increased mortality of adult trees through lateral opening of the trunks causing later breakage.
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BFBNIB, NMLJ, NUK, PNG, SAZU, UL, UM, UPUK
Blood product suppliers have two options for blood collection: at fixed sites and mobile collection sites. Those preferring voluntary, unpaid donations must move ever closer to the population by ...organizing mobile collection. The objective of this study was to analyze the impact of mobile collection in the production of the Côte d'Ivoire's CNTS. Our results, based on data from the CNTS from 2014 through 2016 and interviews with 22 managers of blood transfusion centers, confirm the increasing preponderance of this approach. Thus, our results raise the problem of blood safety in a context where the prevalence of transfusion-transmissible infections is higher in mobile collections, where most donors are giving blood for the first time.
The levels of immune response to SARS-CoV-2 infection or vaccination are poorly understood in African populations and is complicated by cross-reactivity to endemic pathogens as well as differences in ...host responsiveness. To begin to determine the best approach to minimize false positive antibody levels to SARS-CoV-2 in an African population, we evaluated three commercial assays, namely Bio-Rad Platelia SARS-CoV-2 Total Antibody (Platelia), Quanterix Simoa Semi-Quantitative SARS-CoV-2 IgG Antibody Test (anti-Spike), and the GenScript cPass™ SARS-CoV-2 Neutralization Antibody Detection Kit (cPass) using samples collected in Mali in West Africa prior to the emergence of SARS-CoV-2. A total of one hundred samples were assayed. The samples were categorized in two groups based on the presence or absence of clinical malaria. Overall, thirteen out of one hundred (13/100) samples were false positives with the Bio-Rad Platelia assay and one of the same one hundred (1/100) was a false positive with the anti-Spike IgG Quanterix assay. None of the samples tested with the GenScript cPass assay were positive. False positives were more common in the clinical malaria group, 10/50 (20%) vs. the non-malaria group 3/50 (6%); p = 0.0374 using the Bio-Rad Platelia assay. Association between false positive results and parasitemia by Bio-Rad remained evident, after adjusting for age and sex in multivariate analyses. In summary, the impact of clinical malaria on assay performance appears to depend on the assay and/or antigen being used. A careful evaluation of any given assay in the local context is a prerequisite for reliable serological assessment of anti-SARS-CoV-2 humoral immunity.
•Fourteen out of one hundred pre-pandemic samples have detectable antibodies.•Antibodies detected do not have neutralizing capacity against SARS-CoV-2.•Relationship between false positivity and clinical malaria is assay specific.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
1. The rate of CO2emission by two major termite species (Ancistrotermes cavithorax and Odontotermes n. pauperans) was studied in a West African savanna (Lamto, Côte d'Ivoire). First, in three major ...savanna types (grassy, shrubby and woody savannas), CO2emission from the soil surface was measured using a closed container system. Control soil without termite fungus-comb chambers, and soil of eroded termite mound with or without Odontotermes fungus-comb chambers was sampled in each savanna type. Second, the mass-specific respiration rate of the different components of termite fungus-comb chambers (i.e. workers, soldiers fungus comb and chamber walls) was measured under laboratory conditions CO2emission by termites at the landscape-scale was computed from both field biomass data and laboratory measurements. 2. Whatever the savanna type, CO2emission from the soil surface was not different between control soil and soil of eroded termite mound without termite fungus-comb chambers, but was significantly higher in areas with fungus-comb chambers than in areas without fungus-comb chambers (10-19 μmol CO2m-2s-1vs 5-10 μmol CO2m-2s-1). 3. The mass-specific respiration rates were higher for individuals of O. pauperans than for individuals of A. cavithorax. Total respiration rate from an individual fungus-comb chamber was around 56 and 143 μmol$\text{CO}_{2}\ \text{h}^{-1}$for Ancistrotermes and Odontotermes, respectively. 4. Despite a low mass-specific respiration rate, fungus comb accounted for 51% of the total respiration flux from whole chambers in Odontotermes and for 82% in Ancistrotermes. The laboratory-derived respiration rate from individual Odontotermes chambers was consistent with the field estimates. 5. At the landscape-scale, the CO2emission due to A. cavithorax and O. pauperans was 0·022 and 0·050 μmol CO2m-2s-1, respectively. This total ($27\cdot 2\ \text{g C m}^{-2}\ \text{years}^{-1}$) represented 4·9% of the total above-ground net primary production in this ecosystem and 11.3% of the carbon not mineralized by annual fires.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NMLJ, NUK, OILJ, PNG, SAZU, SBCE, SBMB, UL, UM, UPUK
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