In vitro anti Mycobacterium tuberculosis H37Rv activity of Lannea acida A. Rich from Burkina Faso

The cytotoxic and anti-Mycobacterium tuberculosis H37Rv activities of hydro-alcoholic extract of Lannea acida A. Rich (Anacardiaceae) were assessed. The cytoxicity evaluation was carried out on THP1 monocytoid cell line (after 24 h at 1; 5 and 10 microg mL(-1)) and showed only a slight modification of lactate dehydrogenase (LDH) release. The rate of monocytes in different stages of mitosis had been amended in absence and presence of extract as follows: Go/G1 58.83-59.83%; synthesis 21.95-18.64%; mitosis 16.67-15.77%; necrosis 2.65-5.64%. The percentage of inhibition of Mycobacterium tuberculosis proliferation was respectively 77.6 and 36.8% at 1.2 and 0.6 mg mL(-1) of extract. This is an interesting experimental study on antimicrobial and immune-stimulating properties of Lannea acida ethanol-water (70% v/v) extract which may contain potential antibacterial and immune-stimulating agents for clinical use.     

Inhibitory effects of fibrinogen on phagocytic killing of streptococcal isolates from humans, cattle and horses

The effects of fibrinogen on phagocytic killing of Streptococcus dysgalactiae from cattle and S. equi from horses were studied in comparison to that of S. pyogenes from humans. Phagocytic killing was determined by a fluorometric microassay using glass adherent polymorphonuclear neutrophils (PMN) from the respective host species, preopsonization with homologous sera led to a dose-dependent increase in phagocytic killing of all streptococcal cultures, preincubation of streptococci with fibrinogen significantly inhibited their phagocytic killing. Fibrinogen had no effect on phagocytic killing of non-fibrinogen binding S. agalactiae cultures. Further characterization studies with S. dysgalactiae and S. pyogenes revealed that a partial inhibition of phagocytic killing could also be achieved by preincubation with monomeric beta-chains of fibrinogen. Digestion of the fibrinogen binding sites on streptococci with proteases resulted in an almost complete loss of the inhibitory effects of fibrinogen on phagocytic killing. It could thus be concluded that by binding fibrinogen animal pathogenic streptococci could evade phagocytic killing in a similar manner as M protein carrying S. pyogenes isolates from human infections.     

Forecasting daily reference evapotranspiration using the Blaney–Criddle model and temperature forecasts

Accurate daily reference evapotranspiration (ET_o) forecast is essential for real-time irrigation scheduling. An attempt was made to forecast ET_o using the Blaney–Criddle (BC) model and temperature forecasts in this study. Daily meteorological data for the period 2000–2014 at five stations in East China were collected to calibrate and validate the BC model against the FAO56 Penman–Monteith (FAO56-PM) model. Temperature forecasts up to 7 days’ lead time for 2012–2014 were input to the calibrated BC model to forecast ET_o. It is found that the performance of the BC model for ET_o forecast is further improved at all stations after monthly calibration. Average accuracy of forecasted ET_o (error within 1.5 mm d^?1) ranged from 82.7% to 89.3%, average values of mean absolute error (MAE) varied between 0.73 and 0.82 mm d^?1, average values of root mean square error (RMSE) ranged from 0.95 to 1.08 mm d^?1, and average values of the correlation coefficient (R) and concordance index (d) were more than 0.75 and 0.89, respectively. Furthermore, the error in ET_o forecast caused by error in temperature forecast is acceptable. The encouraging results indicate that the proposed method can be an alternative and effective solution for forecasting daily ET_o in East China.     

Soil organic carbon dynamics and crop yield for different crop rotations in a degraded ferruginous tropical soil in a semi-arid region: a simulation approach

In recent years, simulation models have been used as a complementary tool for research and for quantifying soil carbon sequestration under widely varying conditions. This has improved the understanding and prediction of soil organic carbon (SOC) dynamics and crop yield responses to soil and climate conditions and crop management scenarios. The goal of the present study was to estimate the changes in SOC for different cropping systems in West Africa using a simulation model. A crop rotation experiment conducted in Farak?-Ba, Burkina Faso was used to evaluate the performance of the cropping system model (CSM) of the Decision Support System for Agrotechnology Transfer (DSSAT) for simulating yield of different crops. Eight crop rotations that included cotton, sorghum, peanut, maize and fallow, and three different management scenarios, one without N (control), one with chemical fertilizer (N) and one with manure applications, were studied. The CSM was able to simulate the yield trends of various crops, with inconsistencies for a few years. The simulated SOC increased slightly across the years for the sorghum-fallow rotation with manure application. However, SOC decreased for all other rotations except for the continuous fallow (native grassland), in which the SOC remained stable. The model simulated SOC for the continuous fallow system with a high degree of accuracy normalized root mean square error (RMSE)=0·001, while for the other crop rotations the simulated SOC values were generally within the standard deviation (s.d.) range of the observed data. The crop rotations that included a supplemental N-fertilizer or manure application showed an increase in the average simulated aboveground biomass for all crops. The incorporation of this biomass into the soil after harvest reduced the loss of SOC. In the present study, the observed SOC data were used for characterization of production systems with different SOC dynamics. Following careful evaluation of the CSM with observed soil organic matter (SOM) data similar to the study presented here, there are many opportunities for the application of the CSM for carbon sequestration and resource management in Sub-Saharan Africa.     

Response of nitrogen use efficient sorghums to nitrogen fertilizer

Little information is available on the response of grain sorghum [Sorghum bicolor (L.) Moench] genotypes differing in nitrogen (N) use efficiency (NUE) (g DM g N^‐1) to added N fertilizer. Such knowledge is important for reducing the reliance upon fertilizer N. A dryland field experiment was conducted in 1993 and 1994 at Mead, NE evaluating the agronomic responsiveness of 13 sorghum genotypes differing in NUE to three N rates (0, 50 and 100 kg N ha^‐1) and also to determine physiological factors that contribute to improved NUE. The experiment was conducted on a fine montmorillonitic, mesic, Typic Argiudoll soil. Total N at maturity, dry matter, and grain yield were used to calculate NUE terms. Genotype differences were found for all measured variables both years, but no N rate by genotype effects were significant. Nitrogen fertilizer enhanced plant N contents and grain yield, but decreased NUE for total biomass and grain production. An early freeze in 1993 markedly reduced the later maturing genotype grain yields which, in turn, influenced NUE group comparisons. All genotypes in the study attained their full yield potential in 1994. The linear response to N rate of the N non‐responsive group was significantly less than the moderately responsive or N responsive group. High NUE sorghums had greater yields than low NUE types averaged over N levels only in 1994 since Naga White, a high NUE type, did not reach maturity in 1993. There was no difference in the linear response to N between these two groups. A linear increase in grain yield with increasing N rate was significantly greater for hybrids than lines. The results suggest that specific selection for high NUE sorghums will not diminish responsiveness to applied N.     

New algebraic formulations of evapotranspiration extracted from gene-expression programming in the tropical seasonally dry regions of West Africa

Within hydrological nonlinear complex functions, taking only few parameters into the modeling process is still a challenging task. The present paper has for objective to investigate for the first time the predictive ability of the Gene-expression Programming (GEP) for modeling reference evapotranspiration (ETo) using routing weather data from the tropical seasonally dry regions of West Africa in Burkina Faso. The regions under study are located in three agro-climatic zones, Bobo Dioulasso in the Guinea Savanna zone, and Dédougou and Fada N’Gourma in the Sudan zone, and Ouagadougou in the Sudano-Sahelian Savanna zone. Several meteorological data combinations are used as inputs to the GEP to estimate ETo, and their performances are evaluated using R ² and RMSE. Statistically, it was found that GEP can be an alternative to the conventional methods, and its accuracy improves significantly up to R ² (0.979) and RMSE(0.108) when critical variables are taking into account in the model. The results revealed that GEP model is fairly a promising approach with the advantage to provide successfully simple algebraic formulas ease to use without recourse to the full set of meteorological data requirement for accurately estimate ETo in Sub-Saharan Africa regions.     

Early mortality of lambs in African traditional livestock production systems

Early mortality of lambs is a major constraint on total productivity. In 6 different environments the early death rate varied from 12 to 30% of all lambs born. Cause of death differed among systems but only a proportion could definitely be ascribed to infectious disease: nutrition, management and other environmental factors also contribute to the mortality rate. Mortality can be reduced by isolating solutions due to any of these factors but best results (lowest death rates) would be obtained by an integrated package containing elements of all these aspects.     

High Genetic Diversity Among Strains of Fusarium oxysporum f. sp. vasinfectum from Cotton in Ivory Coast

ABSTRACT Seventeen isolates of Fusarium oxysporum f. sp. vasinfectum from the Ivory Coast were characterized using vegetative compatibility group (VCG), restriction fragment length polymorphism of the ribosomal inter-genic spacer region (IGS), and mating type (MAT) idiomorph, and compared with a worldwide collection of the pathogen containing all available reference strains. Some of the isolates were identical to known reference strains for all three traits, whereas others had previously unknown varieties of IGS and (possibly) VCG. One or the other MAT idiomorph was present in each of the new isolates and the reference strains. The new isolates and reference strains were grouped based upon the three traits. Strains from the Ivory Coast were found in 7 of 11 groups detected, suggesting multiple sources for Fusarium wilt in the country. Despite the presence of both MAT idiomorphs among isolates, no evidence for recombination was found.