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Pretoria, South Africa

Carsan S.,International Center for Research in Agroforestry | Stroebel A.,National Research Foundation NRF | Dawson I.,James Hutton Institute | Kindt R.,International Center for Research in Agroforestry | And 2 more authors.
Biodiversity and Conservation | Year: 2013

Small coffee farms around Mount Kenya in Kenya contain many planted and remnant tree species but little is known in the region about the relationship between trees on farms and the methods and dynamics of coffee production. Shifts in production may alter tree diversity and potentially impact on future biodiversity conservation efforts by affecting niches available for indigenous trees on farms. Here, knowledge was gathered on how changes in coffee production on 180 small farms around Mount Kenya may affect tree diversity, categorizing farms according to coffee yield levels over a period of five years as increasing, decreasing or stable production. Tree species richness, abundance and composition were analyzed using species accumulation curves, Rènyi diversity profiles, rank abundance and ecological distance ordinations, and the effects of coffee production examined using quasi-Poisson generalized linear regressions. Species richness were positively correlated with tree basal area but negatively related to coffee, banana and maize yields value. A difference in average tree species richness, abundance and basal area on increasing farms was observed compared to the decreasing and stable farms, even though formal tests on richness and densities differences were inconclusive. These dynamics do not significantly influence vegetation structure but seem to have a bearing on species composition on farms of different coffee production. The overall low abundance (23 % of trees) but high richness (78 % of species) of indigenous trees on coffee farms could change markedly if the dynamics observed in the current study persist, indicating the need for the development of intensified multi-species cropping systems. © 2013 Springer Science+Business Media Dordrecht. Source

Anh Nguyen Thai Q.,Jeju National University | Sharma N.,Jeju National University | Cho K.K.,Gyeongnam National University of Science and Technology | Yeo T.J.,Gyeongnam National University of Science and Technology | And 6 more authors.
Biotechnology and Biotechnological Equipment | Year: 2014

Wood creosote, an herbal anti-diarrheal and a mixture of major volatile compounds, was tested for its non-toxicological effects, using a rat model, with the objective to use the creosote as an antibiotic substitute. A total of 30 Sprague-Dawley rats were studied to form five groups with 6 rats each. Korea beechwood creosote was supplemented into three test groups with 0.03 g/kg, 0.07 g/kg and 0.1 g/kg body weight/day without antibiotic support, along with a positive control of Apramycin sulphate (at 0.5% of the daily feed) and a negative control. Korean beechwood creosote supplementation showed no negative effect on the body weight gain in comparison to the negative and the positive control groups and the feed conversion ratio was also comparable with that of the control groups. The clinical pathology parameters studied were also under the umbrella of normal range, including liver specific enzymes, blood glucose, total protein, blood urea nitrogen (BUN), which indicated no toxic effect of creosote at the given doses. The non-hepatotoxic effect was also confirmed using hepatic damage specific molecular markers like Tim-p1, Tim-p2 and Tgf-b1. The results suggested that Korean beechwood may be used as antibiotic substitute in weanling pigs feed without any toxic effect on the body. Although the antimicrobial properties of creosote were not absolutely similar to those of apramycin sulphate, they were comparable. © 2014 The Author(s). Source

Carsan S.,International Center for Research in Agroforestry | Stroebel A.,National Research Foundation NRF | Dawson I.,International Center for Research in Agroforestry | Kindt R.,International Center for Research in Agroforestry | And 3 more authors.
Current Opinion in Environmental Sustainability | Year: 2014

Agricultural commodity production in a changing climate scenario is undergoing sustainability challenges due to degradation of soil fertility, water and biodiversity resources. In Africa, yields for important cereals (e.g., maize) have stagnated at 1tha-1 due to land degradation, low fertilizer use and water stress. Resource-conserving options such as agroforestry promote integrated management systems that relate livelihoods and ecosystem service functions to agricultural production. Low input practices including improved fallows using legumes in rotations or intercrops can restore soil nutrients, improve soil carbon and reduce reliance on fertilizer use by 50%. We review how agroforestry can sustain agricultural intensification in Africa by regulating ecosystem functions such as nutrient recycling, water use, species diversity and agrochemical pollution. © 2013 The Authors. Source

Webster I.,Stellenbosch University | Webster I.,National Research Foundation NRF | Smith A.,Stellenbosch University | Smith A.,National Research Foundation NRF | And 3 more authors.
Cardiovascular Drugs and Therapy | Year: 2014

Aims: In isolated rat heart perfusion experiments, drug administration occurs via retrograde perfusion. This can be done in the non-recirculating mode (coronary effluent is discarded), or recirculating mode (coronary effluent is collected and reused). It was recently observed in our lab while using sanguinarine, an MKP-1 inhibitor, that there were differences in outcomes depending on the mode of recirculation used.Methods and Results: Hearts from control (C); diet-induced obese (DIO) Wistar rats and their age matched controls (AMC) were perfused on the rig. Hearts received buffer (control) , insulin, sanguinarine, insulin + sanguinarine combination or methanol (vehicle) for 15mins pre- and 10mins post-ischemia in either a non- or re-circulating manner. Hearts were subjected to 15mins global ischemia and 30mins reperfusion. Mechanical function was documented pre- and post-ischemia. When not-recirculated , sanguinarine alone and in combination with insulin in C, DIO and AMC groups, caused a significant decrease in functional recovery during reperfusion. However, when the coronary effluent was recirculated, hearts perfused with sanguinarine or sanguinarine + insulin exhibited a significant recovery in function when compared with their non-recirculation counterparts (p < 0.01). No differences were seen with either control, insulin nor vehicle hearts.Conclusion: Sanguinarine elicited a vast improvement in perfusion outcomes when recirculated compared to non-recirculation. Since this was seen during perfusion only when sanguinarine was present, it is possible that recirculating reperfusion of the drug caused profound changes in its composition. More investigation is needed into the mechanisms involved. Thus caution should be exercised by researchers when designing a perfusion protocol for drug research. © 2014, Springer Science+Business Media New York. Source

Kruger J.,University of Pretoria | Minnis-Ndimba R.,National Research Foundation NRF | Mtshali C.,National Research Foundation NRF | Minnaar A.,University of Pretoria
Food Chemistry | Year: 2015

Cowpea is a nutritionally important drought-resistant legume in sub-Saharan Africa. It is, however, underutilised, in part due to the hard-to-cook (HTC) defect caused by adverse storage conditions resulting in seeds not softening during cooking. This study introduced a novel evaluation of the potential role that minerals play in the development of the HTC defect. The mineral distribution in the cotyledons of normal and HTC cowpeas were analysed by Proton Induced X-ray Emission (PIXE) spectrometry. The phytate, tannin and total phenolic contents were analysed together with in vitro mineral bioaccessibility. In HTC cowpeas, Ca and Mg were more concentrated in the cell wall-middle lamella area of the parenchyma cells. This, together with the reduction in phytate content, confirmed the 'phytase-phytate-mineral' hypothesis as a mechanism for development of the HTC defect. Despite the phytate reduction in stored cowpeas, the HTC defect decreased the bioaccessibility of Ca, Fe and Zn in cowpeas. © 2014 Elsevier Ltd. All rights reserved. Source

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