Search

Deficient skeletal muscle regeneration, which often leads to permanent sequelae, is a common clinical finding in envenomations caused by snakes of the family Viperidae, such as those of Bothrops alternatus and B. diporus in South America. The causes of such poor muscle regenerative outcome are still incompletely understood. Using a murine experimental model of envenomation by the venoms of these two species, we assessed whether traces of venom components that remain in muscle tissue days after envenomation affect myoblasts and myotube formation in culture. The kinetics of drop in venom concentration in the tissue was assessed by ELISA and Western blot, and by the quantification of venom phospholipase A 2 activity. A rapid drop of venom components was observed in muscle, although a band of 58–63 kDa remained even 168 h after venom injection, and venom phospholipase A 2 activity was detected in muscle tissue days after envenomation. Muscle homogenates from envenomated animals were cytotoxic to myoblasts in culture and inhibited the formation of myotubes even in conditions where homogenates were devoid of cytotoxicity. These deleterious effects were abrogated when homogenates were incubated with antivenom. Our findings agree with previous observations with the venom of Bothrops asper and provide further evidence that one of the causes of the poor skeletal muscle regeneration after Bothrops sp venom-induced myonecrosis is the deleterious action on myogenic cells of traces of venom components remaining in the tissue. [Display omitted] • Traces of Bothrops alternatus and B. diporus venoms preclude in vitro muscle regeneration. • Muscle homogenates obtained from envenomed animals were cytotoxic to myoblasts in culture. • Neutralization of venom components may contribute to an improved regenerative response. [ABSTRACT FROM AUTHOR]

Toads are considered poisonous animals since they have a passive mode of defence relying on cutaneous poison glands, differently from venomous animals who can inject venom in predators/aggressors or prey. Toads of Rhinella marina group are generally large and have a broad distribution in South America, inhabiting a wide range of environments. In this paper, we studied the toads Rhinella icterica from the Atlantic rainforest, and Rhinella jimi from the Brazilian Semiarid Caatinga, analysing aspects of natural history and comparing their skin morphology, the presence of macroglands, their resistance to water loss and rates of water uptake. In periods of extreme drought, R. jimi uses rock cracks as refuges, exposing only the head and regions of accumulation of poison glands. The skin of R. jimi showed higher number of poison glands with hydrophilic content than R. icterica. R. jimi also had a thicker skin, which can be related to its superior resistance to water loss. It also showed high rates of rehydration in association with a peculiar behaviour using the limbs to spread water onto highly glandular skin areas, suggesting that poison glands may also act in water balance in addition to chemical defence. [ABSTRACT FROM AUTHOR]

Loxosceles spiders are found in almost all countries of South America. In Peru, Loxosceles laeta species is the main responsible for the accidents caused by poisonous animals, being known as "killer spiders", due to the large number of fatal accidents observed. Astacin-like metalloproteases, named LALPs (Loxosceles astacin-like metalloproteases) are highly expressed in Loxosceles spiders venom gland. These proteases may be involved in hemorrhage and venom spreading, being relevant to the envenoming proccess. Thus, the aim of this work was to analyze Peruvian L. laeta venom gland transcripts using bioinformatics tools, focusing on LALPs. A cDNA library from Peruvian L. laeta venom glands was constructed and sequenced by MiSeq (Illumina) sequencer. After assembly, the resulting sequences were annotated, seeking out for similarity with previously described LALPs. Nine possible LALPs isoforms from Peruvian L. laeta venom were identified and the results were validated by in silico and in vitro experiments. This study contributes to a better understanding of the molecular diversity of Loxosceles venom and provide insights about the action of LALPs. • Peruvian Loxosceles laeta venom was recognized by anti-rLALP1 antibodies. • Peruvian L. laeta venom had greater proteolytic activity than the Brazilian venom. • Nine possible LALP isoforms from Peruvian L. laeta venom were identified by RNAseq. • Peruvian L. laeta LALPs were structurally different from other described LALPs. [ABSTRACT FROM AUTHOR]

Accidents involving spiders from the genus Loxosceles cause medical emergencies in several countries of South America. The species Loxosceles laeta is ubiquitously present in Peru and is responsible for severe accidents in this country. To further characterize L. laeta venom components and to unveil possible variations in the Peruvian population, we provide an overview of the toxins-related transcripts present in the venom gland of Peruvian L. laeta. A dataset from a cDNA library previously sequenced by MiSeq sequencer (Illumina) was re-analyzed and the obtained data was compared with available sequences from Loxosceles toxins. Phospholipase-D represent the majority (69,28 %) of the transcripts related to venom toxins, followed by metalloproteases (20,72 %), sicaritoxins (6,03 %), serine-proteases (2,28 %), hyaluronidases (1,80 %) and Translationally Controlled Tumor Protein (TCTP) (0,56 %). New sequences of phospholipases D,sicaritoxins, hyaluronidase, TCTP and serine proteinases were described. Differences between the here-described toxin sequences and others, previously identified in venom glands from other spiders, were visualized upon sequence alignments. In addition, an in vitro hyaluronidase activity assay was also performed to complement comparisons between Peruvian and Brazilian L. laeta venom enzymatic activities, revealing a superior activity in the venom from Brazilian specimens. These new data provide a molecular basis that can help to explain the difference in toxicity among L. laeta venoms from different countries in South America. [Display omitted] • Toxin expression in Peruvian Loxosceles laeta spiders' venom glands were determined. • Phospholipases D (PLD) were the main toxins expressed (69.28 %), followed by metalloproteinases (20.72 %) and sicaritoxins (6.03 %). • New complete toxin sequences from different families were described for Loxosceles. • In vitro hyaluronidase activity assay of venoms revealed higher activity of Brazilian L. laeta , compared to Peruvian spiders. [ABSTRACT FROM AUTHOR]

• Crotamine and crotalicidin, bioactive and multifunctional venom peptides. • Crotamine and crotalicidin are related to AMPs from mammals and reptiles. • NrTPs, crotamine-derived, display cell-penetrating and cargo-delivery capabilities. • Crotalicidin (vipericidin) is a cathelicidin expressed in the rattlesnake venom gland. • Ctn[15–34], a crotalicidin peptide with anti-infective and antiproliferative effects. A global public health crisis has emerged with the extensive dissemination of multidrug-resistant microorganisms. Antimicrobial peptides (AMPs) from plants and animals have represented promising tools to counteract those resistant pathogens due to their multiple pharmacological properties such as antimicrobial, anticancer, immunomodulatory and cell-penetrating activities. In this review, we will focus on crotamine and crotalicidin, which are two interesting examples of membrane active peptides derived from the South America rattlesnake Crotalus durrisus terrificus venom. Their full-sequences and structurally-minimized fragments have potential applications, as anti-infective and anti-proliferative agents and diagnostics in medicine and in pharmaceutical biotechnology. [ABSTRACT FROM AUTHOR]