Phenotypic and Physiological Aspects Related to Drought Tolerance in Sorghum

Drought is one of the major limitations to crop productivity worldwide. Identifying suitable screening tools and quantifiable traits would facilitate the crop improvement process for drought tolerance in sorghum. This study evaluated phenotypic characteristics and physiological parameters determine which cultivars are more drought tolerant. Signs of drought intolerance in sorghum include leaf rolling, death of lower leaves, stunted growth and low yields. Experiments were conducted using 8 and 25 sorghum accessions planted at two sites in Kenya, namely; Biotechnology Centre and Kiboko Research site, respectively, for evaluation and seeds maintenance. Based on phenotypic characteristic of the 25 cultivars evaluated, the best drought tolerant cultivars were, IS.13615, KAK1950, KBM078, E-36.1, B-35, KBM-003 and IE SV 92036. These observations were specifically deduced from their performance, root characteristics, tillering ability and leaf parameters as drought tolerance indicators. B 35 and E-36 ranked the highest relative water content in leaves, hence more drought tolerant.La s\ue9cheresse est l'une des contraintes majeures \ue0 la productivit\ue9 des cultures dans le monde. L'identification des outils d'\ue9tude et des caract\ue8res quantifiables pourrait faciliter le processus d'am\ue9lioration de la culture de sorgho pour la tol\ue9rance \ue0 la s\ue9cheresse. Cette \ue9tude avait pour but l'\ue9valuation des caract\ue9ristiques ph\ue9notypiques et des param\ue8tres physiologiques pour d\ue9terminer les cultivars les plus tol\ue9rants \ue0 la s\ue9cheresse. Les signes de l'intol\ue9rance \ue0 la s\ue9cheresse englobent l'enroulement de la feuille, la mort des feuilles les plus basses, croissance rabougrie et r\ue9duction de rendement. Les essais \ue9taient conduits en utilisant 8 et 25 accessions de sorgho plant\ue9es dans deux sites au Kenya, \ue0 savoir le centre de Biotechnologie et le site de recherche de kiboko, respectivement, pour l'\ue9valuation et la maintenance des semences. Bas\ue9 sur les caract\ue9ristiques ph\ue9notypiques de 25 cultivars \ue9valu\ue9s, les meilleurs cultivars en terme de tol\ue9rance \ue0 la s\ue9cheresse \ue9taient: IS.13615, KAK1950, KBM078, E-36.1, B-35, KBM-003 et IE SV 92036. Ces observations \ue9taient sp\ue9cifiquement d\ue9duites de leur performance, caract\ue9ristiques des raciness, la capacit\ue9 de tallage et les param\ue8tres des feuilles comme indicateurs de tol\ue9rance \ue0 la s\ue9cheresse. B 35 et E-36 avaient une teneur relative plus \ue9lev\ue9e en eau et par cons\ue9quent les plus tol\ue9rants \ue0 la s\ue9cheresse

Diurnal oscillation of SBE expression in sorghum endosperm

Spatial and temporal expression patterns of the sorghum SBEI, SBEIIA and SBEIIB genes, encoding, respectively, starch branching enzyme (SBE) I, IIA and IIB, in the developing endosperm of sorghum (Sorghum bicolor) were studied. Full-length genomic and cDNA clones for sorghum was cloned and the SBEIIA cDNA was used together with gene-specific probes for sorghum SBEIIB and SBEI. In contrast to sorghum SBEIIB, which was expressed primarily in endosperm and embryo, SBEIIA was expressed also in vegetative tissues. All three genes shared a similar temporal expression profile during endosperm development, with a maximum activity at 15-24 days after pollination. This is different from barley and maize where SBEI gene activity showed a significantly later onset compared to that of SBEIIA and SBEIIB. Expression of the three SBE genes in the sorghum endosperm exhibited a diurnal rhythm during a 24-h cycle

Linking diet switching to reproductive performance across populations of two critically endangered mammalian herbivores.

Optimal foraging theory predicts that animals maximise energy intake by consuming the most valuable foods available. When resources are limited, they may include lower-quality fallback foods in their diets. As seasonal herbivore diet switching is understudied, we evaluate its extent and effects across three Kenyan reserves each for Critically Endangered eastern black rhino (Diceros bicornis michaeli) and Grevy's zebra (Equus grevyi), and its associations with habitat quality, microbiome variation, and reproductive performance. Black rhino diet breadth increases with vegetation productivity (NDVI), whereas zebra diet breadth peaks at intermediate NDVI. Black rhino diets associated with higher vegetation productivity have less acacia (Fabaceae: Vachellia and Senegalia spp.) and more grass suggesting that acacia are fallback foods, upending conventional assumptions. Larger dietary shifts are associated with longer calving intervals. Grevy's zebra diets in high rainfall areas are consistently grass-dominated, whereas in arid areas they primarily consume legumes during low vegetation productivity periods. Whilst microbiome composition between individuals is affected by the environment, and diet composition in black rhino, seasonal dietary shifts do not drive commensurate microbiome shifts. Documenting diet shifts across ecological gradients can increase the effectiveness of conservation by informing habitat suitability models and improving understanding of responses to resource limitatio

Prevalence and risk factors associated with the occurrence of Campylobacter sp. in children aged 6–24 months in peri-urban Nairobi, Kenya

IntroductionCampylobacter bacteria is a major cause of foodborne-related bacterial gastroenteritis in humans worldwide. It is known to cause diarrhea in young children which has been shown to directly affect their weight and height as a result of malnutrition. Severe cases of diarrhea can also lead to death. Most of the burden is experienced in resource-limited countries in Africa and Southeast Asia where the disease is linked to poor hygiene and sanitation. The objective of this study was to determine the prevalence of Campylobacter in children aged between 6 and 24 months in Nairobi, Kenya and identify potential risk factors associated with their occurrence.MethodsA cross-sectional study was carried out between May to December 2021. A total of 585 randomly selected households were visited in two wards (Uthiru/Ruthimitu and Riruta) in Dagoretti South sub-county, Nairobi. A questionnaire regarding how children’s food is handled, the major foods consumed, sanitation and hygiene, and animal ownership was conducted among caregivers to identify associated risk factors. Stool samples were collected from 540/585 children and screened for the presence of Campylobacter using culture-based methods and confirmed through PCR.ResultsOf the 540 children’s stool samples processed, Campylobacter isolates were detected in 4.8% (26/540). Campylobacter jejuni (C. jejuni) was the most common species in 80.8% of positive samples compared to Campylobacter coli (C. coli) in 26.9% of samples. In six samples, both C. jejuni and C. coli were isolated, while in four samples, it was not possible to speciate the Campylobacter. Drinking cow’s milk (OR 4.2, 95% CI 1.4 – 12.6) and the presence of animal feces in the compound (OR 3.4, 95% CI 1.1 – 10.3) were found to be statistically associated with Campylobacter carriage in children.DiscussionThe carriage of Campylobacter in children in this community indicates a need for further investigation on source attribution to understand transmission dynamics and inform where to target interventions. Awareness creation among caregivers on good personal and food hygiene is needed, including boiling milk before consumption. Implementation of biosecurity measures at the household level is highly recommended to reduce contact between animals and humans

Conservation research in times of COVID-19 - the rescue of the northern white rhino

COVID-19 has changed the world at unprecedented pace. The measures imposed by governments across the globe for containing the pandemic have severely affected all facets of economy and society, including scientific progress. Сonservation research has not been exempt from these negative effects, which we here summarize for the BioRescue project, aiming at saving the northern white rhinoceros (Ceratotherium simum cottoni), an important Central African keystone species, of which only two female individuals are left. The development of advanced assisted reproduction and stem-cell technologies to achieve this goal involves experts across five continents. Maintaining international collaborations under conditions of national shut-down and travel restrictions poses major challenges. The associated ethical implications and consequences are particularly troublesome when it comes to research directed at protecting biological diversity – all the more in the light of increasing evidence that biodiversity and intact ecological habitats might limit the spread of novel pathogens

Amyloid precursor protein drives down-regulation of mitochondrial oxidative phosphorylation independent of amyloid beta

Amyloid precursor protein (APP) and its extracellular domain, soluble APP alpha (sAPPα) play important physiological and neuroprotective roles. However, rare forms of familial Alzheimer’s disease are associated with mutations in APP that increase toxic amyloidogenic cleavage of APP and produce amyloid beta (Aβ) at the expense of sAPPα and other non-amyloidogenic fragments. Although mitochondrial dysfunction has become an established hallmark of neurotoxicity, the link between Aβ and mitochondrial function is unclear. In this study we investigated the effects of increased levels of neuronal APP or Aβ on mitochondrial metabolism and gene expression, in human SH-SY5Y neuroblastoma cells. Increased non-amyloidogenic processing of APP, but not Aβ, profoundly decreased respiration and enhanced glycolysis, while mitochondrial DNA (mtDNA) transcripts were decreased, without detrimental effects to cell growth. These effects cannot be ascribed to Aβ toxicity, since higher levels of endogenous Aβ in our models do not cause oxidative phosphorylation (OXPHOS) perturbations. Similarly, chemical inhibition of β-secretase decreased mitochondrial respiration, suggesting that non-amyloidogenic processing of APP may be responsible for mitochondrial changes. Our results have two important implications, the need for caution in the interpretation of mitochondrial perturbations in models where APP is overexpressed, and a potential role of sAPPα or other non-amyloid APP fragments as acute modulators of mitochondrial metabolism

Community-level epidemiology of soil-transmitted helminths in the context of school-based deworming: Baseline results of a cluster randomised trial on the coast of Kenya.

TRIAL REGISTRATION: ClinicalTrials.gov NCT02397772