over distances resulting in the rapid spread of the species. The sterile fruit is small (about 2-2.5 cm), green to red, and slightly spiny with a depressed umbilicus. All detached cladodes and fruit when falling to the ground can root and grow to form new plants. Opuntia pubescens can be confused with the jointed cactus (Opuntia aurantiaca) and the bur cactus (Opuntia salmiana). The impacts of O. pubescens are not yet known but it is suspected that they will be similar to the notorious jointed cactus (O. aurantiaca) which entails a decrease in the grazing area for livestock; injuries to humans and livestock; loss of vegetation; lowered value of pasture; displacement of indigenous plants and curtailed movement of animals and people in the infested area.Biosphere reserves (BRs), as multi-use conservation landscapes, exemplify the landscape mosaic approach to environmental decision-making. With dual biodiversity conservation and sustainable development objectives, they provide a long-term perspective that aims to improve the relationship between traditional conservation and sustainable use; providing local communities with options to sustainably manage environmental resources into the future. South Africa has six BRs listed with UNESCO's Man and the Biosphere Programme (MaB), with the Kruger to Canyons Biosphere Reserve (K2C) in the north-eastern South Africa being one of the largest globally. K2C is a spatially structured socio-ecological system, with important economic sectors and world-renowned protected areas proximal to extensive, mostly rural, human populations engaged in informal livelihood practices. In this study, time-series remotely-sensed data (1993-2006-2012) was used to track landscape transformation across the subregion, analyzing spatial changes in cover relative to the theoretical MaB concept. The focus is on changes in the scale of landcover change (spatial extent, rate, intensity of change) across the analysis period, simulating future changes to 2018 and 2024. Results indicate that the spatial distribution of these land-cover changes bear little regard for the prescriptive BR zonation and the relative limitations on 'use' that typifies successful BR implementation. The increased rate of change in the recent observation period (2.3% versus 5.7%) poses challenges for landscape management, with future predictions of escalating transformation likely to undermine BR sustainability long-term. Consequently, the thresholds for scheduling proactive management action have been identified, allowing for a timely detection of unfavorable transformations while practical options for intervention remain.
Malaria and tuberculosis are among the most common death causes and threats to human life globally. In a quest to find new antimalarial and anti-mycobacterial drugs, oleanolic acid (OA) was isolated from the flower buds of Syzygium aromaticum Linn (Myrtaceae). The derivative, 3-O-Acetyl-Oleanolic acid (OAA), was synthesized from the isolated product and the biological activities of the two compounds were compared. The antiplasmodial and antimycobacterial activity of oleanolic acid and its derivative were investigated against Plasmodium falciparum (Chloroquine Sensitive Strain) NF54 and Mycobacterium tuberculosis H37Rv. OAA exhibited IC50 of 4.3 µg/ml against P. falciparum, compared with an IC50 of 27.4 µg/ml for OA, while against M. tuberculosis OAA showed 0.1 µg/ml, compared with an IC50 of 0.042 µg/ml for OA. In the cytotoxicity studies, using the MTT assay, both compounds exhibited LC50 of > 300 µg/ml against both human embryonic kidney (HEK293) and hepatocellular carcinoma cell lines (HepG2), suggesting that the compounds are not cytotoxic at low to moderate concentrations against the tested cell lines. In conclusion, the derivative OAA improved the antiplasmodial activity but no improvement was shown for antimycobacterial activity, in comparison with the starting material OA. Thus, more derivatives could be designed, using OA as starting material, to obtain future antiplasmodial compounds.
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