292 research outputs found

    ECONOMIC IMPACTS OF REGULATIONS TO PRESERVE NATIVE WOODLAND ON PRIVATE PROPERTY: A CASE STUDY IN THE HUNTER VALLEY OF NEW SOUTH WALES

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    Australian policies to preserve native vegetation on farms rest on mandatory regulations without compensation, whereas policies in most OECD countries rest on voluntary conservation with compensation. In New South Wales, the Native Vegetation Conservation Act 1998 restricts farmers from clearing native vegetation on their own freehold land, and offers no compensation. The Act may therefore impose opportunity costs, or losses in income, on landholders. These opportunity costs are estimated for a case study property in the Hunter Valley of New South Wales, and these results are then generalised to assess the broad trade-offs between development and preservation. The losses in income appear to vary between 5 and 10 per cent of annual income, depending on livestock prices. The flow of these losses over time appears to total some $26m for all properties of this kind in the immediate region. In addition to imposition of these direct opportunity costs, the regulations hinder land sales and so hinder adjustment by landholders to changing conditions.Native vegetation, environmental preservation, opportunity cost., Land Economics/Use,

    Reality check for malaria proteomics

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    Post-translationally modified protein isoforms are common in red blood cell stages of the malaria parasite

    The significance of the F variant of alpha-1-antitrypsin and unique case report of a PiFF homozygote

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    BACKGROUND: Inheritance of the F variant of alpha-1-antitrypsin is associated with normal circulating protein levels, but it is believed to be dysfunctional in its ability to inhibit neutrophil elastase and therefore has been implicated as a susceptibility factor for the development of emphysema. In this study, its functional characteristics were determined following the identification of a unique patient with the PiFF phenotype, and the implications as a susceptibility factor for emphysema are considered both in homozygotes and heterozygotes. METHODS: Second order association rate constants were measured for M, Z, S and F variants of alpha-1-antitrypsin with neutrophil elastase and proteinase 3. Clinical characteristics of the PiFF homozygote and six PiFZ heterozygote subjects were studied. RESULTS: The F variant had a reduced association rate constant with neutrophil elastase (5.60 ± 0.83 × 10(6) M(-1) s(-1)) compared to the normal M variant (1.45 ± 0.02 × 10(7) M(-1) s(-1)), indicating an increased time to inhibition that was comparable to that of the Z variant (7.34 ± 0.03 × 10(6) M(-1) s(-1)). The association rate constant for the F variant and proteinase 3 (1.06 ± 0.22 × 10(6) M(-1) s(-1)) was reduced compared to that with neutrophil elastase, but was similar to that of other alpha-1-antitrypsin variants. Of the six PiFZ heterozygotes, five had airflow obstruction and radiological evidence of emphysema. The PiFF homozygote had airflow obstruction but no emphysema. None of the patients had clinical evidence of liver disease. CONCLUSIONS: The F variant may increase susceptibility to elastase-induced lung damage but not emphysema, whereas co-inheritance with the Z deficiency allele may predispose to emphysema despite reasonable plasma concentrations of alpha-1-antitrypsin

    A malaria membrane skeletal protein is essential for normal morphogenesis, motility, and infectivity of sporozoites

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    Membrane skeletons are structural elements that provide mechanical support to the plasma membrane and define cell shape. Here, we identify and characterize a putative protein component of the membrane skeleton of the malaria parasite. The protein, named PbIMC1a, is the structural orthologue of the Toxoplasma gondii inner membrane complex protein 1 (TgIMC1), a component of the membrane skeleton in tachyzoites. Using targeted gene disruption in the rodent malaria species Plasmodium berghei, we show that PbIMC1a is involved in sporozoite development, is necessary for providing normal sporozoite cell shape and mechanical stability, and is essential for sporozoite infectivity in insect and vertebrate hosts. Knockout of PbIMC1a protein expression reduces, but does not abolish, sporozoite gliding locomotion. We identify a family of proteins related to PbIMC1a in Plasmodium and other apicomplexan parasites. These results provide new functional insight in the role of membrane skeletons in apicomplexan parasite biology

    A Plasmodium falciparum Strain Expressing GFP throughout the Parasite's Life-Cycle

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    The human malaria parasite Plasmodium falciparum is responsible for the majority of malaria-related deaths. Tools allowing the study of the basic biology of P. falciparum throughout the life cycle are critical to the development of new strategies to target the parasite within both human and mosquito hosts. We here present 3D7HT-GFP, a strain of P. falciparum constitutively expressing the Green Fluorescent Protein (GFP) throughout the life cycle, which has retained its capacity to complete sporogonic development. The GFP expressing cassette was inserted in the Pf47 locus. Using this transgenic strain, parasite tracking and population dynamics studies in mosquito stages and exo-erythrocytic schizogony is greatly facilitated. The development of 3D7HT-GFP will permit a deeper understanding of the biology of parasite-host vector interactions, and facilitate the development of high-throughput malaria transmission assays and thus aid development of new intervention strategies against both parasite and mosquito

    Aluminum Direct Chill Casting Mold Metal Shutoff Methods

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    The systems and methods described herein may prevent mold damage, which would otherwise result in significant down time and costly repairs or replacement

    Plasmodium berghei calcium-dependent protein kinase 3 is required for ookinete gliding motility and mosquito midgut invasion

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    Apicomplexan parasites critically depend on a unique form of gliding motility to colonize their hosts and to invade cells. Gliding requires different stage and species-specific transmembrane adhesins, which interact with an intracellular motor complex shared across parasite stages and species. How gliding is regulated by extracellular factors and intracellular signalling mechanisms is largely unknown, but current evidence suggests an important role for cytosolic calcium as a second messenger. Studying a Plasmodium berghei gene deletion mutant, we here provide evidence that a calcium-dependent protein kinase, CDPK3, has an important function in regulating motility of the ookinete in the mosquito midgut. We show that a cdpk3(–) parasite clone produces morphologically normal ookinetes, which fail to engage the midgut epithelium, due to a marked reduction in their ability to glide productively, resulting in marked reduction in malaria transmission to the mosquito. The mutant was successfully complemented with an episomally maintained cdpk3 gene, restoring mosquito transmission to wild-type level. cdpk3(–) ookinetes maintain their full genetic differentiation potential when microinjected into the mosquito haemocoel and cdpk3(–) sporozoites produced in this way are motile and infectious, suggesting an ookinete-limited essential function for CDPK3

    Hemolytic C-Type Lectin CEL-III from Sea Cucumber Expressed in Transgenic Mosquitoes Impairs Malaria Parasite Development

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    The midgut environment of anopheline mosquitoes plays an important role in the development of the malaria parasite. Using genetic manipulation of anopheline mosquitoes to change the environment in the mosquito midgut may inhibit development of the malaria parasite, thus blocking malaria transmission. Here we generate transgenic Anopheles stephensi mosquitoes that express the C-type lectin CEL-III from the sea cucumber, Cucumaria echinata, in a midgut-specific manner. CEL-III has strong and rapid hemolytic activity toward human and rat erythrocytes in the presence of serum. Importantly, CEL-III binds to ookinetes, leading to strong inhibition of ookinete formation in vitro with an IC50 of 15 nM. Thus, CEL-III exhibits not only hemolytic activity but also cytotoxicity toward ookinetes. In these transgenic mosquitoes, sporogonic development of Plasmodium berghei is severely impaired. Moderate, but significant inhibition was found against Plasmodium falciparum. To our knowledge, this is the first demonstration of stably engineered anophelines that affect the Plasmodium transmission dynamics of human malaria. Although our laboratory-based research does not have immediate applications to block natural malaria transmission, these findings have significant implications for the generation of refractory mosquitoes to all species of human Plasmodium and elucidation of mosquito–parasite interactions
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