INTEGRATING CASSAVA VARIETIES AND Typhlodramulus aripo TO SUSTAIN BIOLOGICAL CONTROL OF CASSAVA GREEN MITE

The cassava green mite (CGM), Mononychellus tanajoa , is a pest that reduces root yield of cassava ( Manihot esculenta Crantz) by 30-80% in the cassava belts of Africa. The objective of this study was to identify cassava varieties that enhance abundance and persistence of Typhlodramulus aripo on cassava and increase its efficiency in controlling CGM. Nine cassava (Manihot esculenta Crantz) varieties were evaluated in Kenya based on CGM abundance and HCN of leaves for their ability to sustain low CGM populations to enhance biocontrol of T. aripo. Cassava fields were surveyed in five agro-ecological zones in Uganda and samples of cassava apices were analysed for cassava varieties to sustain high population of T. aripo. In the screening study of CGM abundance and HCN content of leaves and the lowest cumulative CGM population densities (<1200 mites/leaf) were recorded on MM97/3567, Tajirika and MM96/9308, with the lowest cyanide content of leaves, 8.5 \ub1 4.9, 12.5 \ub1 3.2 and 12.3 \ub1 2.5 mg kg-1, respectively. Cassava varieties with hairy and non-hairy tips sustained T. aripo with highest densities (0.96 actives per tip) on hairy TME14. High T. aripo population densities corresponded to high densities of hairs on cassava tips. There were significant inverse linear relationships between CGM densities and T. aripo on TME14 at moderate CGM population densities (CGM damage level 2).Le tantinet vert de la cassave (CGM), Mononychellus tanajoa , est un insecte nuisible qui r\ue9duit la production de racine de cassave ( Manihot esculenta Crantz) de 30-80 % dans les ceintures de cassave de l\u2019Afrique. L\u2019objectif de cette \ue9tude \ue9tait d\u2019identifier des vari\ue9t\ue9s de cassave qui am\ue9liorent l\u2019abondance et la persistance de Typhlodramulus aripo sur la cassave et augmentent son efficacit\ue9 dans le contr\uf4le de CGM. Neuf cassave (Manihot esculenta Crantz) les vari\ue9t\ue9s ont \ue9t\ue9 \ue9valu\ue9es au Kenya bas\ue9 sur l\u2019abondance CGM et HCN de part pour leur capacit\ue9 de soutenir bas des populations de CGM pour am\ue9liorer biocontrol de T. aripo. Les champs de cassave ont \ue9t\ue9 \ue9tudi\ue9s dans cinq zones agro-\ue9cologiques en Ouganda et les \ue9chantillons de sommets de cassave ont \ue9t\ue9 analys\ue9s pour les vari\ue9t\ue9s de cassave pour soutenir la haute population de T. aripo. Dans l\u2019\ue9tude de projection d\u2019abondance CGM et de contenu de HCN de cong\ue9s et des densit\ue9s d\ue9mographiques CGM cumulatives les plus basses (<1200 tantinets/feuille) ont \ue9t\ue9 enregistr\ue9s sur MM97/3567, Tajirika et MM96/9308, avec le contenu de cyanure le plus bas de cong\ue9s, 8.5 \ub1 4.9, 12.5 \ub1 3.2 et 12.3 kg de 2.5 mgs \ub1 1, respectivement. Les vari\ue9t\ue9s de cassave avec les bouts poilus et non-poilus ont soutenu T. aripo avec les plus hautes densit\ue9s (0.96 actives par bout) sur TME14 poilu. Haut T. aripo les densit\ue9s d\ue9mographiques a correspondu \ue0 de hautes densit\ue9s de hairs sur les bouts de cassave. Il y avait des rapports lin\ue9aires inverses significatifs entre les densit\ue9s CGM et T. aripo sur TME14 aux densit\ue9s d\ue9mographiques CGM mod\ue9r\ue9es (le niveau de dommage de CGM 2)

Amides are excellent mimics of phosphate internucleoside linkages and are well tolerated in short interfering RNAs

RNA interference (RNAi) has become an important tool in functional genomics and has an intriguing therapeutic potential. However, the current design of short interfering RNAs (siRNAs) is not optimal for in vivo applications. Non-ionic phosphate backbone modifications may have the potential to improve the properties of siRNAs, but are little explored in RNAi technologies. Using X-ray crystallography and RNAi activity assays, the present study demonstrates that 3\u27-CH2-CO-NH-5\u27 amides are excellent replacements for phosphodiester internucleoside linkages in RNA. The crystal structure shows that amide-modified RNA forms a typical A-form duplex. The amide carbonyl group points into the major groove and assumes an orientation that is similar to the P-OP2 bond in the phosphate linkage. Amide linkages are well hydrated by tandem waters linking the carbonyl group and adjacent phosphate oxygens. Amides are tolerated at internal positions of both the guide and passenger strand of siRNAs and may increase the silencing activity when placed near the 5\u27-end of the passenger strand. As a result, an siRNA containing eight amide linkages is more active than the unmodified control. The results suggest that RNAi may tolerate even more extensive amide modification, which may be useful for optimization of siRNAs for in vivo applications

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

Global Public Health exploring the impact of COVID-19 pandemic lockdown on informal settlements in Tshwane Gauteng Province, South Africa

Informal settlements remain a public health problem as they lack basic infrastructure. Furthermore, it is challenging to enforce public health regulations and protocols to prevent the spread of infection during a pandemic. This paper was set out to explore the impact of lockdown during COVID-19 among people living in informal settlements. An exploratory qualitative design was utilised. Purposive sampling was used to select research participants. In-depth one-to-one interviews were held involving 30 research participants through a WhatsApp online telephone platform. A thematic approach underpinned by the four stages of data analysis in interpretive phenomenological analysis was utilised to analyse the data. The study found that during the the research participants were affected by lack of space to practice social distancing, over-burdened infrastructure, lack of savings, loss of income and shortage of food, hunger and diseases, anxiety and depression and poor access to education. There is a need to prioritise the needs of informal settlers and endeavour to establish permanent homes. Health promotion and communication initiatives and pandemic awareness programmes are needed to mitigate the impact of lockdown during a pandemic in informal settlements

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

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