145 research outputs found

    A tentative approach to the molecular structure of humic acids: the spectral evidence for a derivation of humic acids from plant-borne esters. 3. Pyrolysis-mass spectrometry.

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    Pyrolysis mass spectrometry of humic acids collected from oak forest litter and humus horizons, of esters extracted from oak leaves and of bark extracts indicated a close relationship between plant esters and humic acids. The data support the hypothesis that humic acids can be derived from simple mixed esters formed in the plants. (Abstract retrieved from CAB Abstracts by CABI’s permission

    A tentative approach to the molecular structure of humic acids: The spectral evidence for a derivation of humic acids from plant-borne esters. 2. Infrared and chemical analyses.

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    It is suggested that: humic acids are polyesters, originate as monomers in the secondary metabolism of both higher and lower plants, and are formed in an acid environment (including high-moor peat); the formation of humic acids is promoted by desiccation, particularly under alkaline conditions; humic acids exhibit keto-enol tautomerism, can form semi-quinones and therefore stable radicals also, and derive their colour from these radicals. (Abstract retrieved from CAB Abstracts by CABI’s permission

    A tentative approach to the molecular structure of humic acids: the spectral evidence for a derivation of humic acids from plant-borne esters. 1. The electron paramagnetic resonance (EPR) spectra.

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    It is suggested, from the evidence of EPR spectra, that humic acids are heterogeneous polymers of mixed esters derived from tannins. (Abstract retrieved from CAB Abstracts by CABI’s permission

    Weinig effect pulsatie-instelling op speenzwelling

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    Bij het melken van een koe gaat het erom de aanwezige melk vlot af te voeren, waarbij de speen niet te zwaar belast mag worden. Om aan beide doelen tegemoet te komen zijn eisen gesteld aan de lengte van de zuig- en rustfase in een pulsatiecyclus. Een pulsatie-instelling waarbij snel wordt gemolken, hoeft niet te leiden tot extra speenzwelling

    A multispecies assessment of wildlife impacts on local community livelihoods

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    Conflicts between the interests of agriculture and wildlife conservation are a major threat to biodiversity and human wellbeing globally. Addressing such conflicts requires a thorough understanding of the impacts associated with living alongside protected wildlife. Despite this, most studies reporting on human‐wildlife impacts and the strategies used to mitigate them focus on a single species, thus over‐simplifying often complex systems of human‐wildlife interactions. In this study, we characterize the spatiotemporal patterns of impacts by multiple co‐occurring species on agricultural livelihoods in the eastern Okavango Delta Panhandle in northern Botswana. Using a database of 3,264 wildlife incidents recorded between 2009 and 2015 by the Department of Wildlife and National Parks, we show that a total of eight species – i.e. African elephant, hippopotamus, cheetah, crocodile, leopard, lion, spotted hyena and African wild dog – appear on incident reports, of which 56.5% are attributed to elephants. Most species were associated with only one type of damage (i.e. either damage to crops or livestock loss). Carnivores were primarily implicated in incident reports related to livestock loss, particularly towards the end of the dry season (May‐October). In contrast, herbivores were associated with crop loss incidents during the wet season (November‐April). Our study illustrates how local communities can face distinct livelihood challenges from different species at different times of the year. Such a multi‐species assessment has important implications for the design of conservation interventions aimed at addressing the costs of living with wildlife, and thereby mitigating the underlying conservation conflict. Our spatiotemporal, multi‐species approach is widely applicable to other regions where sustainable and long‐term solutions to conservation conflicts are needed for local communities and biodiversity

    NADPH Oxidase Limits Innate Immune Responses in the Lungs in Mice

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    Background: Chronic granulomatous disease (CGD), an inherited disorder of the NADPH oxidase in which phagocytes are defective in generating superoxide anion and downstream reactive oxidant intermediates (ROIs), is characterized by recurrent bacterial and fungal infections and by excessive inflammation (e.g., inflammatory bowel disease). The mechanisms by which NADPH oxidase regulates inflammation are not well understood. Methodology/Principal Findings: We found that NADPH oxidase restrains inflammation by modulating redox-sensitive innate immune pathways. When challenged with either intratracheal zymosan or LPS, NADPH oxidase-deficient p47phox-/- mice and gp91phox-deficient mice developed exaggerated and progressive lung inflammation, augmented NF-kB activation, and elevated downstream pro-inflammatory cytokines (TNF-α, IL-17, and G-CSF) compared to wildtype mice. Replacement of functional NADPH oxidase in bone marrow-derived cells restored the normal lung inflammatory response. Studies in vivo and in isolated macrophages demonstrated that in the absence of functional NADPH oxidase, zymosan failed to activate Nrf2, a key redox-sensitive anti-inflammatory regulator. The triterpenoid, CDDO-Im, activated Nrf2 independently of NADPH oxidase and reduced zymosan-induced lung inflammation in CGD mice. Consistent with these findings, zymosan-treated peripheral blood mononuclear cells from X-linked CGD patients showed impaired Nrf2 activity and increased NF-kB activation. Conclusions/Significance: These studies support a model in which NADPH oxidase-dependent, redox-mediated signaling is critical for termination of lung inflammation and suggest new potential therapeutic targets for CGD

    Procjena cito-/genotoksičnosti irinotekana u V79-stanicama primjenom komet-testa, mikronukleus-testa i testa kromosomskih aberacija

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    Irinotecan is a topoisomerase I interactive agent, widely used in the treatment of metastatic colorectal cancer. The genotoxic effects of the maximum single dose (18 μg mL-1), recommended monotherapy dose (9 μg mL-1), and recommended combined therapy dose (4.5 μg mL-1) of irinotecan were studied on V79 cells using the comet assay, chromosome aberration assay, and micronucleus test. The cells were treated with irinotecan for 2 h or 24 h. The statistical signifi cance of the results was determined using the one-way ANOVA test and a nonparametric Mann Whitney U test. The comet assay did not show dose-dependent or time-dependent effects. The chromosome aberration analysis showed large DNA rearrangements, i.e., chromosome exchanges. Although the exposed cultures showed a signifi cant increase in micronucleated cells in respect to control, no dose-dependent relation was established among the treated cultures. Timedependent effect was also not observed.Irinotekan je citotoksični lijek koji inhibira enzim DNA-topoizomerazu I. U širokoj je primjeni u terapiji metastatskog karcinoma kolona i rektuma. U uvjetima in vitro primjenom komet-testa, analize kromosomskih aberacija i mikronukleus-testa na V79-stanicama istražili smo genotoksični učinak maksimalne pojedinačne doze (18 μg mL-1), preporučene monoterapijske doze (9 μg mL-1) i preporučene doze irinotekana za kombiniranu terapiju (4,5 μg mL-1). Kulture stanica bile su tretirane irinotekanom 2 h i 24 h. Statistička značajnost određivana je jednosmjernim ANOVA-testom i neparametrijskim Mann Whitneyevim U-testom. Komet-testom nije utvrđen učinak koncentracije i/ili vremena izloženosti. Analiza kromosomskih aberacija pokazala je prisutnost izmjena kromatida, tj. porast broja triradijusa i tetraradijusa. Iako je u kulturama stanica izloženi irinotekanu opažen značajan porast broja mikronukleusa u odnosu na kontrolu, nije uočena ovisnost o dozi lijeka ni o vremenu izloženosti u opisanim eksperimentalnim uvjetima. Dobiveni rezultati upućuju na genotoksičnost irinotekana za V79-stanice. Nijednom od primijenjenih metoda nije utvrđena ovisnost učinka irinotekana o vremenu ili dozi
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