Fabrication and Characterization of Nanocomposite Hydrogel Based on Alginate/Nano-Hydroxyapatite Loaded with Linum usitatissimum Extract as a Bone Tissue Engineering Scaffold

In the current paper, we fabricated, characterized, and applied nanocomposite hydrogel based on alginate (Alg) and nano-hydroxyapatite (nHA) loaded with phenolic purified extracts from the aerial part of Linum usitatissimum (LOH) as the bone tissue engineering scaffold. nHA was synthesized based on the wet chemical technique/precipitation reaction and incorporated into Alg hydrogel as the filler via physical cross-linking. The characterizations (SEM, DLS, and Zeta potential) revealed that the synthesized nHA possess a plate-like shape with nanometric dimensions. The fabricated nanocomposite has a porous architecture with interconnected pores. The average pore size was in the range of 100–200 µm and the porosity range of 80–90%. The LOH release measurement showed that about 90% of the loaded drug was released within 12 h followed by a sustained release over 48 h. The in vitro assessments showed that the nanocomposite possesses significant antioxidant activity promoting bone regeneration. The hemolysis induction measurement showed that the nanocomposites were hemocompatible with negligible hemolysis induction. The cell viability/proliferation confirmed the biocompatibility of the nanocomposites, which induced proliferative effects in a dose-dependent manner. This study revealed the fabricated nanocomposites are bioactive and osteoactive applicable for bone tissue engineering applications.     

Cultivation systems using vegetation cover Improves Sustainable Production and Nutritional Quality of New Rice for Africa in the Tropics

Little is known about the impact of direct sowing under vegetation cover on the production and quality of New Rice for Africa(NERICA) on poor oxisol. In this study, two NERICA varieties(NERICA 3 and NERICA 8) were grown under tropical oxisol soil with very low nutrient contents. Four cultivation systems were used in completely randomized block design, including plowing(control), unplowed soil with dead vegetation cover(DVC), unplowed soil with live vegetation cover(LVC) and unplowed soil with mixed vegetation cover(MVC). DVC significantly improved the exponential growth of NERICAs. NERICA 3 was the more productive(2.16–3.05 t/hm~2) compared with NERICA 8(0.71–1.21 t/hm~2). Cultivation systems improved the nutritional quality of NERICAs. The total protein content of NERICA 3 under DVC and MVC was 84.8% and 75.0% higher than control, respectively. The total soluble carbohydrate contents of NERICA 8 under LVC and MVC was 73.2% and 57.3% higher than control, respectively. These results suggested that conservative approach like direct sowing on unplowed soil with vegetation cover systems can improve the nutritional quality of rainfed NERICAs and their sustainable production under poor oxisol soil in sub-Saharan Africa.     

冠突散囊菌和植物乳杆菌联合发酵对绿茶液态饮料品质的影响

为了抑制冠突散囊菌发酵绿茶液态饮料中儿茶素的降解,本研究采用植物乳杆菌和冠突散囊菌对绿茶液态饮料进行联合发酵,试验通过响应面法优化了联合发酵绿茶液态饮料工艺,并采用高效液相色谱（HPLC）法和顶空固相微萃取串联气质联用（HS-SPME/GS-MS）法分别检测了联合发酵绿茶液态饮料中儿茶素含量和香气成分。结果表明,在干茶添加量10βg·L^-1、冠突散囊菌添加量10βmL·L^-1的前提下,联合发酵绿茶液态饮料的最佳工艺条件为植物乳杆菌添加量20βmL·L^-1、蔗糖添加量75βg·L^-1、30℃下静置发酵3βd。在此工艺下联合发酵绿茶液态饮料中总儿茶素含量为1β419.94βμg·mL^-1,与冠突散囊菌发酵绿茶液态饮料（848.72βμg·mL^-1）相比,显著增加（P<0.05）;且醇类化合物（30.27%）、醛类化合物（15.25%）、烃类化合物（11.35%）、酯类化合物（9.86%）和酮类化合物（9.01%）含量与未发酵绿茶液态饮料相比均显著增加（P<0.05）。     

Cowpea (Vigna unguiculata): Genetics,genomics and breeding

Cowpea, Vigna unguiculata (L.), is an important grain legume grown in the tropics where it constitutes a valuable source of protein in the diets of millions of people. Some abiotic and biotic stresses adversely affect its productivity. A review of the genetics, genomics and breeding of cowpea is presented in this article. Cowpea breeding programmes have studied intensively qualitative and quantitative genetics of the crop to better enhance its improvement. A number of initiatives including Tropical Legumes projects have contributed to the development of cowpea genomic resources. Recent progress in the development of consensus genetic map containing 37,372 SNPs mapped to 3,280 bins will strengthen cowpea trait discovery pipeline. Several informative markers associated with quantitative trait loci (QTL) related to desirable attributes of cowpea were generated. Cowpea genetic improvement activities aim at the development of drought tolerant, phosphorus use efficient, bacterial blight and virus resistant lines through exploiting available genetic resources as well as deployment of modern breeding tools that will enhance genetic gain when grown by sub‐Saharan Africa farmers.     

Endogenous uric acid and urea metabolism in the chicken

1. Four chickens were used in nine successive experiments using a single injection radioisotope dilution technique to study the kinetics of endogenous uric acid and urea metabolism. 2. Starvation lowered uric acid and urea entry rates, but elevated the extent of degradation of these compounds. 3. Urea turnover time and the extent of urea pool degradation were higher, and urea excretion rate was lower than that of uric acid. 4. In colostomised chickens, the extent of uric acid and urea degradation were lower than in non-colostomised birds. 5. The average uric acid and urea entry rates in chickens fed on a diet containing 200 g protein/kg were 7.32 and 2.6 mumol/h g liver, respectively. 6. It is concluded that the contribution of uric acid and urea to the nitrogen economy of the birds is negligible.     

Kinetics of microbial phosphorus uptake in cultivated soils

Knowledge about the role of microorganisms in P cycling at conditions of constant soil respiration rates and constant size of microbially bound P is lacking. To study the kinetics of microbial P uptake and cycling under such conditions, soils differing in biological activity were ³³PO₄ labelled by introducing a carrier-free tracer solution and incubated for 56 days. The ³³PO₄ incorporation into the fraction of microbial P releasable by chloroform treatment (P_chl) was assessed and the isotopic composition [=specific activity (SA); SA=³³PO₄/³¹PO₄] of P_chl and soil solution P compared. Soils were taken from a 20-year-old field experiment including a non-fertilised control (NON), a minerally fertilised conventional (MIN) and two organic farming systems [bio-organic (ORG); bio-dynamic (DYN)]. Tracer P incorporation continuously increased during incubation in DYN, ORG and MIN soils. It decreased in the order DYN>ORG>MIN, with differences in ³³PO₄ uptake between the farming systems being higher than suggested by the differences in the amount of P_chl. In the P-deficient NON soil, the highest initial incorporation of tracer P was found, but no additional uptake could be detected thereafter. In all soils, the SA of P_chl converged to the SA of the soil solution with increasing time. Since P_chl remained almost constant during the experiment, the findings suggest an intensive uptake of P from the soil solution into P_chl and concomitant release of P back to the soil solution and, thus, a rapid cycling through P_chl. Intensive P cycling between P_chl and the soil solution was confirmed in an additional experiment where microbial activity was stimulated by glucose and N additions.     

Association and Path Coefficients Analysis of Fresh Root Yield of High and Low Cyanide Cassava (Manihot esculenta Crantz) Genotypes in the Humid Tropics

Thirty-eight high- and low-cyanide cassava genotypes were examined in the 2004 and 2005 cropping seasons at Umudike, southeastern Nigeria using RCBD with three replications. Simple correlation associations and path coefficients analyses were computed among agronomic characters with the aim of understanding the interrelationships of these characters and the extent of their contribution to the root yield of cassava. There was a significant (P 2 0.05) positive correlation between root yield and number of roots plant-1 with correlation coefficients (r) of 0.57, average weight of root (r = 0.58) in high-cyanide cassava genotypes, while in low cyanide cassava genotypes, fresh root yield was highly significantly (P 2 0.01) correlated with average weight of root (r = 0.74). Path analysis showed that average weight of root had the highest direct effect in high (0.66) and in low cyanide (0.67) cassava genotypes. Also, the number of roots plant-1 in both types of cassava exerted a positive direct effect on fresh root yield, however, a minimum effect was obtained by number of leaves plant-1 (0.22) in high-cyanide cassava and number of stems plant-1 (-0.13) in lowcyanide cassava genotypes. Average weight of roots in high- and low-cyanide cassava genotypes had 98 and 89% direct effects, respectively, on yield of cassava. The results indicated the importance of average weight of roots and other characters such as number of roots plant-1, plant height, and number of leaves plant-1 in determining increased yield hence priority must be accorded it during selection aimed at increasing cassava root yield.     

Investigation of African swine fever in slaughtered pigs,Plateau state,Nigeria, 2004-2006

The occurrence of African swine fever (ASF) DNA in slaughtered pigs in the major pig producing areas of Plateau state over a 2-year period was investigated. Three hundred fifty-nine pig tissue samples from five local government councils (LGCs) were analyzed by clinical signs (C/S), postmortem (PM) lesions and polymerase chain reaction (PCR). The results of diagnosis made by C/S and PM were compared to results obtained by PCR. Out of the 359 abattoir samples, 13 (3.62%) were positive by examination of C/S and PM lesions while 346 (96.38%) were negative. Jos-north LGC had the highest occurrence of PCR positive samples (31 samples); Panyam in Mangu LGC had no positive result. PCR analysis identified 53 positive samples (14.76%); more than 40 were identified on the field. Of the samples, 306 were PCR negative, thus giving a true ASF status of pigs in Plateau state. Analysis of the results, variables involved in the ASF spread and predictable effects of such findings in the pig industry in Plateau state and Nigeria as a whole is discussed.     

Acaricidal efficacy against cattle ticks and acute oral toxicity of Lippia javanica (Burm F.) Spreng

Tropical Animal Health and Production - In search for low-cost, safe and environmentally benign plant-based alternatives to commercial pesticides, the efficacy of Lippia javanica aqueous leaf...     

Accruing genetic gain in pro-vitamin A enrichment from harnessing diverse maize germplasm

Maize has been targeted as one of the major crops for provitamin enrichment and delivery because it is an inexpensive and easily available source of food for millions of people in sub-Saharan Africa. Although tropical-adapted yellow maize contains provitamin-A carotenoids that can be converted into vitamin A in the human body, they represent less than 25% of the total carotenoids in most widely grown and consumed maize cultivars in Africa. Novel genes conditioning high concentration of β-carotene and other carotenoids were then continually introduced from the temperate zone and tropics to boost provitamin A in tropical-adapted maize. Several promising inbred lines developed from backcrosses involving diverse exotic donor lines displayed provitamin A concentrations that match or surpass the current breeding target of 15 μg g^?1. Some of these lines attained high provitamin A content by accumulating mainly high β-carotene while others contained high provitamin A by promoting accumulation of high levels of both carotenes and xanthophylls. Several inbred lines with intermediate to high levels of provitamin A have already been used to develop hybrids and synthetics without compromising grain yield and other adaptive traits that are required to profitably cultivate maize by farmers in West and Central Africa.