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Medical Sciences	50%

Selected Abstracts

Changes in hydrology and erosion over a transition from grassland to shrubland

HYDROLOGICAL PROCESSES, Issue 4 2010
Laura Turnbull
Abstract The degradation of grasslands is a common problem across semi-arid areas worldwide. Over the last 150 years, much of the south-western United States has experienced significant land degradation, with desert grasslands becoming dominated by shrubs and concurrent changes in runoff and erosion which are thought to propagate further the process of degradation. Plot-based experiments to determine how spatio-temporal characteristics of soil moisture, runoff and erosion change over a transition from grassland to shrubland were carried out at four sites over a transition from black grama (Bouteloua eriopoda) grassland to creosotebush (Larrea tridentata) shrubland at the Sevilleta NWR LTER site in New Mexico. Each site consisted of a 10 × 30 m bounded runoff plot and adjacent characterization plots with nested sampling points where soil moisture content was measured. Results show distinct spatio-temporal variations in soil moisture content, which are due to the net effect of processes operating at multiple spatial and temporal scales, such as plant uptake of water at local scales versus the redistribution of water during runoff events at the hillslope scale. There is an overall increase in runoff and erosion over the transition from grassland to shrubland, which is likely to be associated with an increase in connectivity of bare, runoff-generating areas, although these increases do not appear to follow a linear trajectory. Erosion rates increased over the transition from grassland to shrubland, likely related in part to changes in runoff characteristics and the increased capacity of the runoff to detach, entrain and transport sediment. Over all plots, fine material was preferentially eroded which has potential implications for nutrient cycling since nutrients tend to be associated with fine sediment. Copyright © 2009 John Wiley & Sons, Ltd. [source]

Ribosome-inactivating proteins isolated from dietary bitter melon induce apoptosis and inhibit histone deacetylase-1 selectively in premalignant and malignant prostate cancer cells

INTERNATIONAL JOURNAL OF CANCER, Issue 4 2009
Su Dao Xiong
Abstract Epidemiologic evidence suggests that a diet rich in fruits and vegetables is associated with a reduced risk of prostate cancer (PCa) development. Although several dietary compounds have been tested in preclinical PCa prevention models, no agents have been identified that either prevent the progression of premalignant lesions or treat advanced disease. Momordica charantia, known as bitter melon in English, is a plant that grows in tropical areas worldwide and is both eaten as a vegetable and used for medicinal purposes. We have isolated a protein, designated as MCP30, from bitter melon seeds. The purified fraction was verified by SDS-PAGE and mass spectrometry to contain only 2 highly related single chain Type I ribosome-inactivating proteins (RIPs), ,-momorcharin and ,-momorcharin. MCP30 induces apoptosis in PIN and PCa cell lines in vitro and suppresses PC-3 growth in vivo with no effect on normal prostate cells. Mechanistically, MCP30 inhibits histone deacetylase-1 (HDAC-1) activity and promotes histone-3 and -4 protein acetylation. Treatment with MCP30 induces PTEN expression in a prostatic intraepithelial neoplasia (PIN) and PCa cell lines resulting in inhibition of Akt phosphorylation. In addition, MCP30 inhibits Wnt signaling activity through reduction of nuclear accumulation of ,-catenin and decreased levels of c- Myc and Cyclin-D1. Our data indicate that MCP30 selectively induces PIN and PCa apoptosis and inhibits HDAC-1 activity. These results suggest that Type I RIPs derived from plants are HDAC inhibitors that can be utilized in the prevention and treatment of prostate cancer. © 2009 UICC [source]

Bark beetles (Coleoptera: Curculionidae: Scolytinae) of importance to the Australian macadamia industry: an integrative taxonomic approach to species diagnostics

AUSTRALIAN JOURNAL OF ENTOMOLOGY, Issue 2 2010
Andrew Mitchell
Abstract Bark beetles are emerging as pests of macadamias, both in the native range of macadamias in Australia and worldwide wherever macadamias are cultivated. Multiple species have been detected on macadamias in Australia; however, little has been known about the identity of the species involved, other than that some belong to the genera Hypothenemus Westwood (1836) and Cryphalus Erichson (1836). Hypothenemus is a large and cosmopolitan genus, which contains two exotic species that are regulated pests for Australia: the tropical nut borer, Hypothenemus obscurus (Fabricius), is a pest of macadamias and Brazil nuts in the Americas and the Pacific, and the coffee berry borer, Hypothenemus hampei (Ferrari), is a pest of coffee found in coffee-growing areas worldwide, but not in Australia. It is essential that biosecurity authorities have reliable species diagnostic tools available in order to detect incursions of these species in Australia. However, the taxonomic literature on the relevant species is scattered and sparse, and the lack of molecular diagnostic methods means that identification of eggs and larvae has been impossible to date because the immature life stages are morphologically homogeneous. This study fills some crucial gaps in our ability to identify these species, developing diagnostic methods for the major pest species on macadamia in Australia, and for key exotic species, including both regulated pests. An integrative taxonomic approach was used incorporating both traditional morphological taxonomy and DNA barcode data in an iterative process to both identify beetles and develop robust diagnostics for them. DNA barcodes provide unambiguous discrimination of all species examined in this study, albeit a limited sample, and have the advantage that they can be used to identify all life stages of the species. [source]

Interdigital lesions and frequency of acute dermatolymphangioadenitis in lymphoedema in a filariasis-endemic area

BRITISH JOURNAL OF DERMATOLOGY, Issue 5 2006
T. McPherson
Summary Background, Lymphatic filariasis (LF) is a mosquito-borne nematode infection that causes permanent lymphatic dysfunction in virtually all infected individuals and clinical disease in a subset of these. One major sequel of infection is lymphoedema of the limbs. Lymphoedema of the leg affects an estimated 15 million persons in LF-endemic areas worldwide. Acute dermatolymphangioadenitis (ADLA) in people with filarial lymphoedema causes acute morbidity and increasingly severe lymphoedema. Episodes of ADLA are believed to be caused by bacteria, and it has been shown that entry lesions in the skin play a causative role. Clinical observations suggest that interdigital skin lesions of the feet, often assumed to be fungal, may be of particular importance. Objectives, To investigate the epidemiology and aetiology of interdigital lesions (IDL) of the feet in filarial lymphoedema. Methods, The frequency and mycological aetiology of IDL in 73 patients with filarial lymphoedema were compared with 74 individuals without lymphoedema in a region of Guyana highly endemic for Wuchereria bancrofti. Results, More than 50% of patients with lymphoedema had one or more IDL (odds ratio 2·69; 95% confidence interval 1·31,5·66; P < 0·005 compared with controls). The number of lesions was the strongest predictor of frequency of ADLA. Only 18% of the lesions had positive microscopy or culture for fungi (dermatophytes and Scytalidium). Conclusions, These findings highlight the importance of interdigital entry lesions as risk factors for episodes of ADLA and have implications for the control of morbidity from filarial lymphoedema. [source]