Forest Clearance and Fragmentation in Palawan and Eastern Mindanao Biodiversity Corridors (1990-2000): A Time Sequential Analysis of LANDSAT Imagery

Conservation International has mapped changes in forest cover in the Philippines over large areas in two biodiversity corridors, as defined by the Critical Ecosystems Partnership Fund (CEPF). These changes were derived by analysing Landsat satellite imagery at a spatial resolution of 28.5 m. The dataset analysed includes Landsat 5 data from circa 1990 (+/- 3 years) and Landsat 7 data from circa 2000. Image dates were determined based on the availability of free, nearly cloud-free imagery from the University of Maryland’s Global Land Cover Facility (http://glcf.umiacs.umd.edu/index.shtml). Additional scenes were also purchased for areas most heavily covered with clouds. A supervised classification approach was employed, using a decision tree classifier. The total amount of forest cleared during the time period was 20.1 km2 in the Eastern Mindanao corridor and 37.5 km2 in the Palawan biodiversity corridor, representing an average annual forest clearance rate of 0.04 percent for Eastern Mindanao and 0.07 percent for Palawan.   Forest fragmentation was also observed to be more apparent in Palawan due to clearance of smaller forest patches.  Forest cover interpretation from the Landsat imagery was validated through a collective aerial system of videography and photography. The combined accuracy of the classified maps was 85.4 percent

Validation of <i>N</i>-myristoyltransferase as Potential Chemotherapeutic Target in Mammal-Dwelling Stages of <i>Trypanosoma cruzi</i>

BACKGROUND:Trypanosoma cruzi causes Chagas disease, an endemic and debilitating illness in Latin America. Lately, owing to extensive population movements, this neglected tropical disease has become a global health concern. The two clinically available drugs for the chemotherapy of Chagas disease have rather high toxicity and limited efficacy in the chronic phase of the disease, and may induce parasite resistance. The development of new anti-T. cruzi agents is therefore imperative. The enzyme N-myristoyltransferase (NMT) has recently been biochemically characterized, shown to be essential in Leishmania major, Trypanosoma brucei, and T. cruzi¸ and proposed as promising chemotherapeutic target in these trypanosomatids. METHODOLOGY/PRINCIPAL FINDINGS:Here, using high-content imaging we assayed eight known trypanosomatid NMT inhibitors, against mammal-dwelling intracellular amastigote and trypomastigote stages and demonstrated that three of them (compounds 1, 5, and 8) have potent anti-proliferative effect at submicromolar concentrations against T. cruzi, with very low toxicity against human epithelial cells. Moreover, metabolic labeling using myristic acid, azide showed a considerable decrease in the myristoylation of proteins in parasites treated with NMT inhibitors, providing evidence of the on-target activity of the inhibitors. CONCLUSIONS/SIGNIFICANCE:Taken together, our data point out to the potential use of NMT inhibitors as anti-T. cruzi chemotherapy

Remote sensing of burn severity and the interactions between burn severity, topography and vegetation in interior Alaska

Thesis (M.S.) University of Alaska Fairbanks, 2004A variety of single-band, band ratio, vegetation index, and multivariate algorithms were evaluated for mapping burn severity using Landsat TM and ETM+ imagery across four burns in interior Alaska. The Normalized Burn Ratio (NBR) outperformed all algorithms, both when tested as a single post-fire value and when tested as a differenced (prefire-postfire) value. The NBR was then used to map burn severity at a historical burn near Yukon-Charley Rivers National Preserve and a time-series of images from 1986 to 2002 was analyzed to investigate interactions between vegetation, burn severity, and topography. Strong interactions existed between vegetation and burn severity, but the only topographic variable that had a significant relationship with burn severity was elevation, presumably due to the strong control of elevation on vegetation type. The highest burn severity occurred in spruce forest, while the lowest occurred in broadleaf forest. Areas with high burn severity experienced disproportionately more shifts toward spruce woodland and shrub classes, while areas with low to moderate severity were less likely to change vegetation type. Finally, vegetation recovery, estimated using a remotely-sensed vegetation index, peaked between 8-14 years post-fire, and recovery was highest for areas with the highest burn severity

Green algae CO 2 capture is powered by alternative electron pathways of photosynthesis

Abstract On Earth, microalgae contribute to about half of global net photosynthesis. During photosynthesis, sunlight is converted into chemical energy (ATP and NADPH) used by metabolism to convert CO 2 into biomass. Alternative electron pathways of photosynthesis have been proposed to generate additional ATP that is required for sustaining CO 2 fixation, but the relative importance of each pathway remains elusive. Here, we dissect and quantify the contribution of cyclic, pseudo-cyclic and chloroplast to mitochondria electron flows for their ability to sustain net photosynthesis in the microalga Chlamydomonas reinhardtii . We show that each pathway has the potential to energize substantial CO 2 fixation, can compensate each other, and that the additional energy requirement to fix CO 2 is more than 3 times higher than previous estimations. We further show that all pathways have very different efficiencies at energizing CO 2 fixation, with the chloroplast-mitochondria interaction being the most efficient, thus laying bioenergetic foundations for biotechnological improvement of CO 2 capture