RESUMEN
Scutigeromorph centipedes are conspicuous, yet often ignored myriapods for which little work has been conducted in southern South America. After examining recent and museum collections from Chile and Argentina, two new species of generic uncertainty were identified. A new genus of scutigerid centipede, Edgethreua , is therefore described with two new species, E. chilensis from Central Chile (type species of the genus) and E. goloboffi from Argentinian Patagonia. The new genus is characterised by the presence of scattered setiform bristles with short paired spines and the absence of simple spinulae and spines on all stomatotergites, the presence of a single spine-bristle in the prefemur of the second maxilla, a patch of cuticular ridges and pores surrounding the sensilla of the proximal labral portion of the epipharynx, the morphology of the sensilla of the distal patch of the hypopharynx and the morphology of the female gonopods. A phylogenetic analysis of the new species using two nuclear ribosomal RNA genes (18S and 28S rRNA), two mitochondrial ribosomal RNA genes (12S and 16S rRNA) and the mitochondrial protein-encoding gene cytochrome c oxidase subunit I show that the new genus does not cluster with any other described genus of scutigeromorph represented in molecular phylogenies. The data indicate that the new genus is probably sister group to a clade including the genera Lassophora , Ballonema and the subfamily Thereuoneminae, although one analysis suggests a position as sister group to Scutigerinae. ZooBank: urn:lsid:zoobank.org:pub:A4D453F3-9031-4E21-84C7-87F16C07AD51.
Asunto(s)
Quilópodos , Filogenia , Animales , Femenino , Masculino , Argentina , Chile , Quilópodos/genéticaRESUMEN
Among the Chilopoda class of centipede, the Cryptops genus is one of the most associated with envenomation in humans in the metropolitan region of the state of São Paulo. To date, there is no study in the literature about the toxins present in its venom. Thus, in this work, a transcriptomic characterization of the Cryptops iheringi venom gland, as well as a proteomic analysis of its venom, were performed to obtain a toxin profile of this species. These methods indicated that 57.9% of the sequences showed to be putative toxins unknown in public databases; among them, we pointed out a novel putative toxin named Cryptoxin-1. The recombinant form of this new toxin was able to promote edema in mice footpads with massive neutrophils infiltration, linking this toxin to envenomation symptoms observed in accidents with humans. Our findings may elucidate the role of this toxin in the venom, as well as the possibility to explore other proteins found in this work.
Asunto(s)
Venenos de Artrópodos/química , Venenos de Artrópodos/toxicidad , Quilópodos/química , Animales , Quilópodos/genética , Edema/inducido químicamente , Perfilación de la Expresión Génica , Sueros Inmunes , Masculino , Ratones Endogámicos BALB C , Proteoma , Conejos , Proteínas RecombinantesRESUMEN
Haemocyanins (Hcs) are copper-containing, respiratory proteins that occur in the haemolymph of many arthropod species. Here, we report the presence of Hcs in the chilopode Myriapoda, demonstrating that these proteins are more widespread among the Arthropoda than previously thought. The analysis of transcriptome of S. subspinipes subpinipes reveals the presence of two distinct subunits of Hc, where the signal peptide is present, and six of prophenoloxidase (PPO), where the signal peptide is absent, in the 75 kDa range. Size exclusion chromatography profiles indicate different quaternary organization for Hc of both species, which was corroborated by TEM analysis: S. viridicornis Hc is a 6 × 6-mer and S. subspinipes Hc is a 3 × 6-mer, which resembles the half-structure of the 6 × 6-mer but also includes the presence of phenoloxidases, since the 1 × 6-mer quaternary organization is commonly associated with hexamers of PPO. Studies with Chelicerata showed that PPO activity are exclusively associated with the Hcs. This study indicates that Scolopendra may have different proteins playing oxygen transport (Hc) and PO function, both following the hexameric oligomerization observed in Hcs.