Characterization of a novel snake venom component: Kazal-type inhibitor-like protein from the arboreal pitviper Bothriechis schlegelii
Artículo académico
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Abstracto
Snake venoms are composed mainly of a mixture of proteins and peptides. Notably, all snake venom toxins have been assigned to a small number of protein families. Proteomic studies on snake venoms have recently identified the presence of Kazal-type inhibitor-like proteins in the neotropical arboreal snakes Bothriechis schlegelii and Bothriechis supraciliaris. In the present study, a Kazal-type component from B. schlegelii, named Kazal-type inhibitor-like protein (KTIL), has been completely sequenced and characterized for the first time. This protein, which contains 54 amino acid residues, shows sequence similarity to the third domain of the ovomucoid from avian species, which is a Kazal-like domain. KTIL did not inhibit the enzymatic activity of various serine proteinases at pH = 7.2 or pH = 8.0, but partially inhibited the activity of trypsin at pH = 5.4, and the only toxic effect in mice observed after different in vivo tests was the induction of footpad edema. KTIL was not lethal when injected in mice or chickens. The presence of Kazal-type proteins and mRNA only in species of the genus Bothriechis suggests a genus recruitment event in the early-Middle Miocene, the estimated time of emergence of this clade.
The collection of scientific data by people without a science degree is at least as old as Antonie van Leeuwenhoek, but thanks to smartphones it now involves large numbers of volunteers, leading to studies about who the so called “citizen scientists” are, how they behave, and how to improve their work. There are, however, no worldwide studies about citizen science projects reporting fauna killed in road collisions. Here we analyze data from the 31 projects available in September 2017 in iNaturalist.org, the largest website for this subject. The USA and Europe have the most projects, but after correcting for population size, countries like Costa Rica and Canada are outstanding, possibly thanks to widespread Internet access and high educational levels. Projects had a mean of 431 observations, 48 species, of 32 volunteers who, on average, posted 19 observations each. Most volunteers contributed few records and were active only briefly. The roadkill data shows that, in the tropics, seasonal mortality trends match the movement of animals in search of water for drinking and for reproduction, while in temperate sites project differences depended mostly on which particular species is studied. We recommend future consideration of how the behavior of volunteers and projects changes along time, a subject that has seldom been considered in previous studies.
