Effect of Moisture Content and Temperature on Viability and Longevity of Cordia Sinensis Lam. Seeds

The main objective of this study was to determine the effect of different temperatures and moisture contents on Cordia simesis seeds viability on storage. Seeds of Cordia sinenis (L) were stored in hermitically corked glass viols for up to 150 days at different constant temperature ranging 60C to 350 C and moisture contents ranging 6% to 18% (fresh weight basis). Seed with different moisture contents were retrieved at intervals of 30 days from different storage temperature regimes for viability for a period of 150 days. Viability and storage period (longevity) decline during storage was generally lower at lower temperatures and moisture contents but rapid at higher temperatures and moisture contents. The effect of storage conditions on viability was also quantified using seedlings requirements equation. The estimated periods for viability to fall to 50% (P50 half-life value) decreased with the increase in seed moisture contents and storage temperatures. The viability results obtained could be used to predict the longevity and expected number of seedlings at different times. The results obtained in the present study could be applied in predicting viability loss and number of seedlings especially under short to medium-term storage conditions. Keywords: viability, longevity, cordia, sinensis, half-lif

Metabolomics Identifies multiple candidate biomarkers to diagnose and stage human African trypanosomiasis

Treatment for human African trypanosomiasis is dependent on the species of trypanosome causing the disease and the stage of the disease (stage 1 defined by parasites being present in blood and lymphatics whilst for stage 2, parasites are found beyond the blood-brain barrier in the cerebrospinal fluid (CSF)). Currently, staging relies upon detecting the very low number of parasites or elevated white blood cell numbers in CSF. Improved staging is desirable, as is the elimination of the need for lumbar puncture. Here we use metabolomics to probe samples of CSF, plasma and urine from 40 Angolan patients infected with Trypanosoma brucei gambiense, at different disease stages. Urine samples provided no robust markers indicative of infection or stage of infection due to inherent variability in urine concentrations. Biomarkers in CSF were able to distinguish patients at stage 1 or advanced stage 2 with absolute specificity. Eleven metabolites clearly distinguished the stage in most patients and two of these (neopterin and 5-hydroxytryptophan) showed 100% specificity and sensitivity between our stage 1 and advanced stage 2 samples. Neopterin is an inflammatory biomarker previously shown in CSF of stage 2 but not stage 1 patients. 5-hydroxytryptophan is an important metabolite in the serotonin synthetic pathway, the key pathway in determining somnolence, thus offering a possible link to the eponymous symptoms of “sleeping sickness”. Plasma also yielded several biomarkers clearly indicative of the presence (87% sensitivity and 95% specificity) and stage of disease (92% sensitivity and 81% specificity). A logistic regression model including these metabolites showed clear separation of patients being either at stage 1 or advanced stage 2 or indeed diseased (both stages) versus control

Growth and Yield Evaluation of \u3ci\u3eUrochloa\u3c/i\u3e Grass Cultivars in Sub-Humid Region of Kenya

Livestock production in sub humid region of Kenya is constrained by inadequate and low quality pasture. A study was conducted to evaluate growth and productivity of eight improved Urochloa grass cultivars in lower midlands, upper midlands and lower highlands agro-ecological zones (AEZ) in Eldoret, Kitale and Alupe respectively, western Kenya. The grass cultivars were; Urochloa brizantha cvs. Marandu, Xaraes, Piata, and MG-4, U. decumbens, cv. Basilisk, U. humidicola cvs. Humidicola and Llanero and Urochloa hybrid cv. Mulato II. Rhodes grass (Chloris gayana) and Napier grass (Pennisetum purpureum cv. Kakamega 1) were included as controls. At establishment stage, growth parameters (height, cover and spread) and dry matter yield (DMY) were monitored at 14 weeks after seedling emergence (WAE) and standardization cut conducted to stimulate uniform plant growth. Thereafter (production stage), the plants were repeatedly harvested for DMY determination at 6, 8 and 12 weeks intervals. The growth parameters and DMY varied significantly (p \u3c 0.05) among the cultivars in all the AEZ in all the measurement dates. Napier grass recorded the highest mean height (60 to 120 cm) at the end of establishment period while among Urochloa cultivars, MG-4, Basilisk and Xaraes recorded the highest mean height and plot cover across all AEZs. All Urochloa cultivars gave significantly (p \u3c 0.05) lower DMY than Napier grass in Kitale and Alupe while Basilisk and Xaraes recorded similar DMY to Napier grass in Eldoret. In Eldoret, Xaraes recorded the highest DMY (2.54 t ha-1) while in Kitale and Alupe the highest DMY was recorded in MG-4 (3.7 t ha-1) and Basilisk (4.72 t ha-1), respectively. Increasing cutting interval increased DMY but reduced nutritive value of Urochloa cultivars in Kitale. Basilisk, MG-4, Xaraes and Piata showed potential to establish and grow well across AEZs and to maximize production and nutritive value cutting at 8 weeks interval is recommended

Soil Microbial Carbon, Nitrate and Ammonium Nitrogen Dynamics in \u3ci\u3eUrochloa\u3c/i\u3e Grass Cultivated in Sub-Humid Kenya

A study was conducted to monitor the dynamics of available soil phosphorus (P), soil microbial biomass carbon (SMBC), nitrogen (SMBN), ammonium and nitrate nitrogen under seven Urochloa grass cultivars at Kitale, Kenya. The Urochloa cultivars: Urochloa brizantha cvs. Marandu, MG-4, Piata, Xaraes, U. decumbens cv. Basilisk, U. hybrid cv. Mulato II and U. humidicola cv. Llanero was compared with two popularly grown forages, Rhodes grass (Chloris gayana cv. KAT R3), Napier grass (Pennisetum purpureum cv. KK1) and annual weeds. The treatments were tested in a randomized complete block design arranged in a split plot treatment structure with two rates of fertilizer N (0 and 100 kg N ha-1yr-1) and P (0 and 40 kg P ha-1) assigned to the main plots and the grass cultivars assigned to the subplots. After 80 weeks, moist rhizosphere soil was sampled at 0 – 10 cm depth to determine microbial biomass. Application of fertilizer N and P did not significantly (P \u3e 0.05) influence SMBC, SMBN, ammonium N (NH4+N) and nitrate N (NO3-N). However, significant (P = 0.001) changes in soil properties, including NH4+N and NO3-N due to grass cultivars, were observed. After 80 weeks, the bare plot, annual weeds and Napier grass accumulated higher pools of ammonium and nitrate N, but the microbial biomass (SMBC and SMBN) in these treatments were lower than in Urochloa grasses. Soil pH was also low, while NO3-N was high indicating increased nitrification in the bare and Napier grass plots. Ammonium N was the most dominant form of inorganic N in Llanero and Piata due to increased plant uptake or reduced nitrification rates. The results suggested that the change in the SMBC and SMBN in the Urochloa grasses was regulated by the nitrate and ammonium N and soil pH

Cellular architecture of spinal granulomas and the immunological response in tuberculosis patients coinfected with HIV

Mycobacterium tuberculosis (M.tb) and HIV are individually responsible for the most deaths worldwide among all infectious agents, and coinfection with M.tb and HIV is a significant public health challenge in the developing world. Although the lung is the primary target organ for tuberculosis (TB), M.tb can also cause extrapulmonary tuberculosis (EPTB) such as in the bones and joints. Treatment of EPTB is much more challenging than treatment of pulmonary TB. The hallmark of the host immune response against TB is the formation of organized structures called granulomas that are infiltrated with immune cells and are rich in cytokines and chemokines. Inside granulomas, the host confines the M.tb bacteria to a particular region of the organ and avoids dispersion. In this study, we analyzed immune cells in bone granulomas of patients with EPTB that are also coinfected with HIV. We found that HIV-infected TB patients have dispersed bone granulomas, with reduced T cell numbers and a concomitant increase in plasma cells. Additionally, HIV-infected patients exhibited dramatically increased serum levels of IgM and IgG1 antibodies, which is indicative of T-cell-independent B-cell activation and mucosal T-cell activation, respectively. Interestingly, we also observed that CD29+ stem cells are increased in HIV–TB coinfection, suggesting a link with HIV infection. Therefore, our work provides new insights into the architecture of spinal TB granulomas and the role of B-cells and humoral immunity against a highly infectious intracellular pathogen. We propose that our findings will inform biomarker identification for EPTB and possibly the development of related therapeutics and/or vaccines to protect HIV-infected patients against disseminated TB

Genetic diversity study of Kenyan cassava germplasm using simple sequence repeats

Cassava (Manihot esculenta Cranzt) is an important food security crop for resource poor rural communities particularly in Africa. Little is however known about molecular diversity of Kenyan cassava germplasm. This led to a study whose objective was to identify genetic constitution of cassava accessions from different regions of Kenya using molecular tools. Seven pairs of micro satellite (SSR) primers previously developed from cassava were used to detect polymorphic 21 alleles in a sample of 69 accessions. The cluster analysis of similarity matrix obtained at 68% with SSR data showed that the 69 accessions were grouped into five marker based groups. This study proved that SSRs could be used to identify cassava accessions as well as in the assessment of level of genetic relatedness among accessions.Keywords: Cassava, simple sequence repeat (SSR) markers, genetic diversity

Spodoptera frugiperda population structure and influence of farmers’ practices on gut biodiversity for sustainable management of the pest in Kenya

Fall armyworm (FAW), Spodoptera frugiperda, is a highly polyphagous pest that recently invaded Kenya, among other African countries. Information on the pest’s genetic diversity and mechanisms conferring insecticide resistance, in addition to farmers’ knowledge and perceptions on the applicable mitigation measures, inform the development of sustainable management strategies. Therefore, this study collected cross-sectional data from 800 farmers in Kenya and documented their knowledge and perceptions on FAW and factors influencing their choice of FAW control methods. Additionally, we identified the strains present in 8 counties in Kenya using the mitochondrial Cytochrome Oxidase sub-unit I (mt COI) gene, and correlated pesticide use to gut microbiome diversity via 16S rRNA metagenomics to investigate the probable contribution of gut bacteria towards insecticide resistance evolution. All farmers reported FAW infestations, and 24% reported limited and total non-response of FAW to insecticides. Fall armyworm rice-strain and corn-strain were detected ravaging corn fields. However, the corn-strain revealed higher microbial diversity than the rice-strain. Furthermore, pathogenic bacterial genera were elevated in the insect gut in both corn and rice strains after chemical-treatments. Insecticide–endosymbiont interactions should be further explored, and farmers’ training on effective alternative pest control methods is recommended

A simplified approach for producing Tier 2 enteric-methane emission factors based on East African smallholder farm data

Context: Accurate reporting of livestock greenhouse-gas (GHG) emissions is important in developing effective mitigation strategies, but the cost and labour requirements associated with on-farm data collection often prevent this effort in low- and middle-income countries. Aim: The aim of this study was to investigate the precision and accuracy of simplified activity data collection protocols in African smallholder livestock farms for country-specific enteric-methane emission factors. Method: Activity data such as live weight (LW), feed quality, milk yield, and milk composition were collected from 257 smallholder farms, with a total herd of 1035 heads of cattle in Nandi and Bomet counties in western Kenya. The data collection protocol was then altered by substituting the actual LW measurements with algorithm LW (ALG), feed quality (FQ) data being sourced from the Feedipedia database, reducing the need for daily milk yield records to a single seasonal milk measurement (MiY), and by using a default energy content of milk (MiE). Daily methane production (DMP) was calculated using these simplified protocols and the estimates under individual and combined protocols were compared with values derived from the published (PUBL) estimation protocol. Key results: Employing the algorithm LW showed good agreement in DMP, with only a small negative bias (7%) and almost no change in variance. Calculating DMP on the basis of Feedipedia FQ, by contrast, resulted in a 27% increase in variation and a 27% positive bias for DMP compared with PUBL. The substitutions of milk (MiY and MiE) showed a modest change in variance and almost no bias in DMP. Conclusion: It is feasible to use a simplified data collection protocol by using algorithm LW, default energy content of milk value, seasonal single milk yield data, but full sampling and analysis of feed resources is required to produce reliable Tier 2 enteric-methane emission factors. Implications: Reducing enteric methane emissions from the livestock is a promising pathway to reduce the effects of climate change, and, hence, the need to produce accurate emission estimates as a benchmark to measure the effectiveness of mitigation options. However, it is expensive to produce accurate emission estimates, especially in developing countries; hence, it is important and feasible to simplify on-farm data collection

A simplified approach for producing Tier 2 enteric methane emission factors based on East African smallholder farm data

Context: Accurate livestock greenhouse gas (GHG) emissions reporting is important in developing effective mitigation strategies, but the cost and labor requirements associated with on-farm data collection often prevent this effort in low-and-middle-income countries. Aim: The aim of this study was to investigate the precision and accuracy of simplified activity data collection protocols in African smallholder livestock farms for country-specific enteric methane emission factors. Method: Activity data such as live weight (LW), feed quality, milk yield, and milk composition were collected from 257 smallholder farms with a total herd of 1,035 heads of cattle in Nandi and Bomet counties in Western Kenya. The data collection protocol was then altered by substituting actual LW measurements with algorithm LW (ALG), feed quality (FQ) data sourced from the Feedipedia database, reducing the need for daily milk yield records to a single seasonal milk measurement (MiY), and using a default energy content of milk (MiE). Daily methane production (DMP) was calculated using these simplified protocols and the estimates under individual and combined protocols were compared with values derived from the published (PUBL) estimation protocol. Key results: Employing the algorithm LW showed good agreement in DMP with only a small negative bias (7%) and almost no change in variance. Calculating DMP based on Feedipedia FQ, by contrast, resulted in a 27% increase in variation and a 27% positive bias for DMP compared to PUBL. The substitutions of milk (MiY and MiE) showed a modest change in variance and almost no bias in DMP. Conclusion: It is feasible to use a simplified data collection protocol by using algorithm LW, default energy content of milk value, seasonal single milk yield data, but full sampling and analysis of feed resources is required to produce reliable Tier 2 enteric methane emission factors. Implications: Reducing enteric methane emissions from the livestock is a promising pathway to reduce the effects of climate change hence the need to produce accurate emissions estimates as benchmark to measure the effectiveness of mitigation options. However, it is expensive to produce accurate emission estimates especially in developing countries, hence important and feasible to simplify on-farm data collection