DNA in Amphibian and Reptile Venom Permits Access to Genomes without Specimen Sacrifice

Abstract

Amphibian defensive skin secretions and reptile venoms are rich sources of bioactive peptides with potential pharmacological/pharmaceutical applications. As amphibian and reptile populations are in rapid global decline, our research group has been developing analytical methods that permit generation of robust molecular data from non-invasive skin secretion samples and venom samples. While previously we have demonstrated that parallel proteome and venom gland transcriptome analyses can be performed on such samples, here we report the presence of DNA that facilitates the more widely-used applications of gene sequencing, such as molecular phylogenetics, in a non-invasive manner that circumvents specimen sacrifi ce. From this "surrogate" tissue, we acquired partial 12S and 16S rRNA gene sequences that are presented for illustration purposes. Thus from a single sample of amphibian skin secretion and reptile venom, robust and complementary proteome, transcriptome and genome data can be generated for applications in diverse scientifi c disciplines.

Proteomic and Genomic Studies on Lizard Venoms in the Last Decade

“…To begin with, the development of a minimally invasive technique for acquiring samples of lizard venoms, along with robust molecular techniques, help provide a consistent and reliable source of valuable lyophilized lizard venoms for intensive proteomic and genomic research studies. 6,7,8,10,13 Secondly, two additional lizard lineages, monitorsincluding the Komodo dragon-and the iguania, were confirmed as possessing toxin-secreting oral glands and venom toxins. 9,12 As a result of these discoveries and reports, new insights into the evolution of the venom system in squamate reptiles have been provided and new avenues have been opened for biomedical investigations into the bioactive profiles of novel components establishing a path of new leads for drug design and development.…”

“…By using the principle of this robust technique, Kwok et al have further demonstrated that parallel proteome and venom gland transcriptome analyses can be performed on such samples. 8 They reported the presence of DNA that facilitates the more widely used applications of gene sequencing, such as molecular phylogenetics, in a non-invasive manner that does not require specimen sacrifice. From this “surrogate” tissue, they successfully acquired partial 12S and 16S rRNA gene sequences that were presented for illustration purposes.…”

“…4 Since then there have been several major research breakthroughs and reports on lizard venom components and evolution in this intervening period. These include 1) the development of a minimally invasive and reliable technique for acquiring lizard venoms, 6 2) the development of robust molecular techniques for constructing cDNA libraries to obtain proteomic and genomic data from lyophilised lizard venom secretions, 7,8 3) the discovery of venom toxins in two additional lizard lineages (varanids and iguania), 9 4) the discovery of novel bradykinin-receptor inhibitory peptides (helokinestatins) in helodermatid ( Heloderma suspectum and Heloderma horridum ) venoms, and 5) the discovery of natriuretic peptide toxins in both helodermatid ( H. suspectum and H. horridum ) and a varanid ( Varanus varius ) venom. 10,11 In addition, a recent study has also demonstrated that Komodo dragons ( Varanus komodoensis ) and the extinct giant Megalania ( Varanus prisca ) possess(ed) venomous bites.…”

Article Commentary: Drug Discovery Benefits from Venomous Clues

“…The answer rests in the rapidly advancing field of functional toxico-genomics and proteomics and the mining of the derived data for novel research-orientated and therapeutically useful compounds in lizard venom without the need to sacrifice the life of the animal. The authors make the case from several seminal studies by Kwok et al 7,8 that from one sample of lizard venom, it is possible to derive complex but complementary data with regard to transcriptome, proteome and genome that can all be applied to scientific and drug discovery applications. Since a modified technique had been developed for the efficient recovery of lizard venom, 9,10 a technique for the non-traumatic and repeated harvesting of lizard venoms for drug discovery and scientific research applications had been standardized.…”