Biochemical characterisation and substrate-specific proteolytic diversity of venom metalloproteinases in African puff adders

Posted by
  By 4028mdk09 - Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=11200575 Biochemical characterisation and substrate-specific proteolytic diversity of venom metalloproteinases in African puff adders Abstract The puff adder ( Bitis arietans ) is a highly venomous viper responsible for many snakebite fatalities in Africa, yet there have been few geographically comprehensive analyses of its venom proteins, particularly of the proteases that play a key role in pathology of envenoming. To address this, we have isolated, identified and characterised the bioactivity of the venom metalloproteases of puff adders obtained from a range of localities. Prominent in all venoms was a PI snake venom metalloproteinase (SVMP), derived from a larger PII precursor. This protein existed as either non-glycosylated (21 kDa) or glycosylated, the latter containing either one (26 kDa) or two N-glycans (30 kDa). All the venoms we tested contained either one or the other form: none had...

Use of geometric morphometrics to distinguish trapdoor spider morphotypes (Mygalomorphae: Anamidae: Proshermacha): a useful tool for mygalomorph taxonomy

Posted by

 


Use of geometric morphometrics to distinguish trapdoor spider morphotypes (Mygalomorphae: Anamidae: Proshermacha): a useful tool for mygalomorph taxonomy

Abstract

Taxonomic studies have evolved greatly since their early stages and new techniques have been incorporated to improve species descriptions. Those involving the comparison of traits, either quantitatively or qualitatively, can be difficult because the identification of a species must rely on the experience of the observer and errors can occur when cryptic species are involved. Molecular methods have been used to fill these gaps, but morphological methods are still needed to match the recognized molecular species with an adequate taxonomic description. Focusing on the trapdoor spider genus Proshermacha Simon, 1908, we provide a case study using Geometric Morphometrics (GM) techniques to identify morphological divergence between species found in the south-western Australia region. We used GM to identify morphological divergence from museum-preserved specimens by examining shape variation of sexual characters from 39 male specimens from five different localities on a single mountain range. Variation in the shape of both the palpal bulb and tibia provided strong evidence to distinguish two morphotypes, while metatarsus shape showed fewer between-locality differences. Our results illustrate the utility of GM methods, when applied to a few taxonomically-informative structures, as a quantitative species delimitation tool for taxonomic studies.

Kevin O. Sagastume-Espinoza, Leigh W. Simmons, Mark S. Harvey "Use of geometric morphometrics to distinguish trapdoor spider morphotypes (Mygalomorphae: Anamidae: Proshermacha): a useful tool for mygalomorph taxonomy," The Journal of Arachnology, 52(1), 31-40, (8 April 2024)