Barietin, a snake venom vascular endothelial growth factor from puff adder Bitis arietans venom, increases the heart rate with minor effect on blood pressure in rats

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  Barietin, a snake venom vascular endothelial growth factor from puff adder Bitis arietans venom, increases the heart rate with minor effect on blood pressure in rats ABSTRACT Snake venom vascular endothelial growth factors (svVEGFs) are homodimeric proteins comprising two equal subunits bound by two intermolecular disulfide bonds. The main biological effects of svVEGFs are local vasodilatation, increasing of vascular permeability, and hypotension. Barietin, a svVEGF purified from the venom of puff adder Bitis arietans , differs from other representatives of this toxin family by its shortened C-terminal amino acid sequence. No data about barietin effects on hemodynamics are available. Studying those in rats we found that barietin at a dose of 1 mg/kg significantly increased heart rate, exerting only a minor influence on blood pressure. In this respect, it differs from other svVEGFs having a significant effect on blood pressure. We aimed to find the barietin active fragment which m...

The spider fauna of Danish coastal dune habitats revisited after 25 years: evidence of faunistic impoverishment

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The spider fauna of Danish coastal dune habitats revisited after 25 years: evidence of faunistic impoverishment

Abstract

Arthropod faunas have become impoverished in recent years in abundance as well as in diversity, but so far little evidence exists concerning spiders. In 2022, we repeated pitfall trap collections of spider assemblages completed 25 years previously in coastal dune habitats of the Hanstholm Reserve of National Park Thy, Denmark. Traps were placed approximately at the same spots, i.e. the habitats (white dune, grey dune, dry dune heathland, wet dune heathland, low pine plantation) were represented approximately as before. Contrary to most previous reports of insect decline, we found only weak evidence of reduction in abundance, but strong indications of reductions in faunistic value based on changes in ecological traits. Within the same period of spring and with the same number of traps, we collected 12% fewer spider individuals and 13% fewer species; rarefaction indicated that the lowered species richness was real. Species diversity had decreased and dominance increased. Changes in indices of ecological traits showed that the fauna had changed into decreased contribution of habitat specialists and species of restricted Danish distribution; the proportion of aeronauts had increased; the average body size had decreased. Indices of assemblage microclimatic niche positions and niche widths showed increased representation of shade and humidity loving species. Most of these changes were repeated in each of the habitats. Finally, we found evidence of a phenological shift towards activity earlier in spring in some species.

Toft, S., Gajdoš, P. The spider fauna of Danish coastal dune habitats revisited after 25 years: evidence of faunistic impoverishment. J Insect Conserv (2024). https://doi.org/10.1007/s10841-024-00567-2