Envenomation caused by Hemiscorpius (H.) lepturus from Liochlidae family presents clinical features that have not been previously described for the Buthidae family scorpions. The most significant ...manifestations of H. lepturus envenomation are hemolysis and dermonecrosis which could lead in severe cases to renal, cardio-respiratory failure, and death. In this study, we aimed to identify and characterize the protein(s) causing these effects. We have purified a 33 kDa protein from the venom of H. lepturus and named it Heminecrolysin. Tryptic digestion and MS/MS analysis of obtained peptides showed homology with previously described brown spider sphingomyelinases D. Functional characterization of Heminecrolysin indicated a sphingomyelinase D, a complement-dependent hemolysis properties and a dermonecrosis activity. Heminecrolysin displayed higher hemolytic activity to human erythrocytes (ED50 of 0.025 μg/ml), a stronger inflammatory and dermonecrotic effects when injected intra-dermally to rabbit skins, while its efficiency to hydrolyze sphingomyelin seems weaker than other known spider dermonecrotic SMasesD (149 ± 32.5 nmol/mg). Step of sensitization of human erythrocytes by Heminecrolysin was shown to be Mg2+ and Ca2+-independent while hemolysis step in the presence of complement required both bivalent ions. Heminecrolysin is the first hemolytic dermonecrotic toxin identified in venom other than spiders. Except in spider Loxosceles genus and some pathogenic strains of Corynebacteria, sphingomyelinase D activity is unknown in the animal kingdom.
► Hemiscorpious lepturus scorpion envenomation shares common clinical features with spider’s. ► Heminecrolysin is the first dermonecrotic toxin purified from scorpion venom. ► Trypsin digest and MS/MS analysis showed homology with brown spider sphingomyelinase D. ► Pharmalogical characterization indicate sphingomyelinase D, complement-dependent hemolysis and dermonecrosis activities.
Animal and human bite wounds represent a significant global health issue. In the United States, animal and human bites are a very common health issue, causing significant morbidity and even, in rare ...scenarios, mortality. Most animal bite wounds in the United States are caused by dogs, with cat bites being a distant second. Human bite wounds constitute a dominant subset of all bite wounds. Several studies of bite wounds have reported improved outcomes with early diagnosis and immediate treatment. However, the available literature on the initial treatment provides a plethora of conflicting opinions and results. In this review, our aim was to identify and assess the current evidence on the management of animal (dog, cat, insects, scorpions, and snakes) and human bite wounds.
Review article, level III.
Abstract
A comprehensive understanding of phylogeography requires the integration of knowledge across different organisms, ecosystems, and geographic regions. However, a critical knowledge gap exists ...in the arid biota of the vast Asian drylands. To narrow this gap, here we test an “out-of-Central Asia” hypothesis for the desert scorpion Mesobuthus mongolicus by combining Bayesian phylogeographic reconstruction and ecological niche modeling. Phylogenetic analyses of one mitochondrial and three nuclear loci and molecular dating revealed that M. mongolicus represents a coherent lineage that diverged from its most closely related lineage in Central Asia about 1.36 Ma and underwent radiation ever since. Bayesian phylogeographic reconstruction indicated that the ancestral population dispersed from Central Asia gradually eastward to the Gobi region via the Junggar Basin, suggesting that the Junggar Basin has severed as a corridor for Quaternary faunal exchange between Central Asia and East Asia. Two major dispersal events occurred probably during interglacial periods (around 0.8 and 0.4 Ma, respectively) when climatic conditions were analogous to present-day status, under which the scorpion achieved its maximum distributional range. M. mongolicus underwent demographic expansion during the Last Glacial Maximum, although the predicted distributional areas were smaller than those at present and during the Last Interglacial. Development of desert ecosystems in northwest China incurred by intensified aridification might have opened up empty habitats that sustained population expansion. Our results extend the spatiotemporal dimensions of trans-Eurasia faunal exchange and suggest that species’ adaptation is an important determinant of their phylogeographic and demographic responses to climate changes.
Scorpions are arachnids that have a generalist diet, which use venom to subdue their prey. The study of their trophic ecology and capture behavior is still limited compared to other organisms, and ...aspects such as trophic specialization in this group have been little explored.
In order to determine the relationship between feeding behavior and venom toxicity in the scorpion species
, 33 specimens were offered prey with different morphologies and defense mechanisms: spiders, cockroaches and crickets. In each of the experiments we recorded the following aspects: acceptance rate, immobilization time and the number of capture attempts. The median lethal dose of
venom against the three different types of prey was also evaluated.
We found that this species does not have a marked difference in acceptance for any of the evaluated prey, but the number of capture attempts of spiders is higher when compared to the other types of prey. The immobilization time is shorter in spiders compared to other prey and the LD
was higher for cockroaches.
These results indicate that
is a scorpion with a generalist diet, has a venom with a different potency among prey and is capable of discriminating between prey types and employing distinct strategies to subdue them.
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•We examined patterns of genetic diversity in the scorpion Paruroctonus boreus.•We found well-supported crown clades separated by short, poorly supported internodes.•Clades were ...either geographically delimited or widespread.•Predicted habitat suitability varied under past climatic conditions.•Our results highlight cryptic genetic diversity in western North American fauna.
Diverse studies in western North America have revealed the role of topography for dynamically shaping genetic diversity within species though vicariance, dispersal and range expansion. We examined patterns of phylogeographical diversity in the widespread but poorly studied North American vaejovid scorpion, Paruroctonus boreus Girard 1854. We used mitochondrial sequence data and parsimony, likelihood, and Bayesian inference to reconstruct phylogenetic relationships across the distributional range of P. boreus, focusing on intermontane western North America. Additionally, we developed a species distribution model to predict its present and historical distributions during the Last Glacial Maximum and the Last Interglacial Maximum. Our results documented complex phylogeographic relationships within P. boreus, with multiple, well-supported crown clades that are either geographically-circumscribed or widespread and separated by short, poorly supported internodes. We also observed subtle variation in predicted habitat suitability, especially at the northern, eastern and southern edges of the predicted distributional range under past climatic conditions. The complex phylogenetic relationships of P. boreus suggests that historical isolation and expansion of populations may have occurred. Variation in the predicted distributional range over time may implicate past climatic fluctuations in generating the patterns of genetic diversity observed in P. boreus. These findings highlight both the potential for cryptic biodiversity in widespread North American scorpion species and the importance of phylogeographical studies for understanding the factors responsible for generating the biodiversity of western North America.
Grafting of exogenous bioactive sites or functional motifs onto structurally stable scaffolds to gain new functions represents an important research direction in protein engineering. Some engineered ...proteins have been developed into therapeutic drugs. MeuNaTxα-3 (abbreviated as MT-3) is a newly characterized scorpion sodium channel toxin-like peptide isolated from the venom of the scorpion Mesobuthus eupeus, which contains a rigid scaffold highly similar to classical scorpion sodium channel toxins and an extension of eight amino acids in its J-loop region. This extended loop constitutes a flexible region extruded from the scaffold and could be substituted by exogenous functional sequences. In this study, we experimentally evaluated the scaffold potential of MT-3 through grafting two small antimicrobial motifs to replace residues within the loop. Functional assays showed that the two engineered molecules exhibited elevated antimicrobial potency, as compared with the unmodified scaffold, without structural disruption, providing experimental evidence in favor of MT-3 as a promising scaffold in protein engineering.
We isolated from the venom of the scorpion Leiurus quinquestriatus hebraeus an extremely active anti-insect selective depressant toxin, Lqh-dprIT(3). Cloning of Lqh-dprIT(3) revealed a gene family ...encoding eight putative polypeptide variants (a-h) differing at three positions (37A/G, 50D/E, and 58N/D). All eight toxin variants were expressed in a functional form, and their toxicity to blowfly larvae, binding affinity for cockroach neuronal membranes, and CD spectra were compared. This analysis links Asn-58, which appears in variants a-d, to a toxin conformation associated with high binding affinity for insect sodium channels. Variants e-h, bearing Asp-58, exhibit a different conformation and are less potent. The importance of Asn-58, which is conserved in other depressant toxins, was further validated by construction and analysis of an N58D mutant of the well-characterized depressant toxin, LqhIT(2). Current and voltage clamp assays using the cockroach giant axon have shown that despite the vast difference in potency, the two types of Lqh-dprIT(3) variants (represented by Lqh-dprIT(3)-a and Lqh-dprIT(3)-e) are capable of blocking the action potentials (manifested as flaccid paralysis in blowfly larvae) and shift the voltage dependence of activation to more negative values, which typify the action of beta-toxins. Moreover, the stronger and faster shift in voltage dependence of activation and lack of tail currents observed in the presence of Lqh-dprIT(3)-a suggest an extremely efficient trapping of the voltage sensor compared to that of Lqh-dprIT(3)-e. The current clamp assays revealed that repetitive firing of the axon, which is reflected in contraction paralysis of blowfly larvae, can be obtained with either the less potent Lqh-dprIT(3)-e or the highly potent Lqh-dprIT(3)-a at more negative membrane potentials. Thus, the contraction symptoms in flies are likely to be dominated by the resting potential of neuronal membranes. This study clarifies the electrophysiological basis of the complex symptoms induced by scorpion depressant toxins in insects, and highlights for the first time molecular features involved in their activity.
Highlights ► 2 kGy of γ-irradiation with dose rate of 765 Gy/h is used to detoxify scorpion venom. ► Conserving its immunogenic properties this toxoid has immunoprotective effect. ► Detoxified ...antigens could be promising tool to improve immunotherapy and as vaccine.
Pseudoscorpions have a sparse fossil record although they are among the oldest terrestrial lineages with origins that go back to the Devonian (ca. 385 Ma). Amongst the 25 extant families of ...pseudoscorpions, only 14 are known from fossils, most of which are preserved in European ambers from the Eocene. Burmese amber from the Cenomanian (mid-Cretaceous) of northern Myanmar is an important source of Mesozoic pseudoscorpion fossils but only six species have been described from this amber to date. In this paper, we establish the first fossil record for the pseudoscorpion family Ideoroncidae Chamberlin, 1930, which is coequally the oldest record of the pseudoscorpion superfamily Neobisioidea. The new genus Proalbiorix is established for the two species P. gracilis sp. nov. and P. compactus sp. nov. which already show all diagnostic features of members belonging to this family to date. Interestingly, Proalbiorix shows morphological features that align the fossils with present-day fauna from the Americas and Africa rather than Asia, which has biogeographical implications. Overall, the description provides another example of relative morphological stasis of pseudoscorpions compared to other arachnid lineages such as spiders, and that all major clades of pseudoscorpions were established long before the Cretaceous.
•First fossil record of Pseudoscorpions of the Ideoroncidae family.•Oldest record of Neobisioidea.•New species Proalbiorix similar to present-day species from the Americas and Africa.•Morphological stasis of pseudoscorpions confirmed.
Several species of Tityus (Scorpiones, Buthidae) present multi-chromosomal meiotic associations and failures in the synaptic process, originated from reciprocal translocations. Holocentric ...chromosomes and achiasmatic meiosis in males are present in all members of this genus. In the present study, we investigated synapse dynamics, transcriptional silencing by γH2AX, and meiotic microtubule association in bivalents and a quadrivalent of the scorpion Tityus maranhensis. Additionally, we performed RT-PCR to verify the expression of mismatch repair enzymes involved in crossing-over formation in Tityus silvestris gonads. The quadrivalent association in T. maranhensis showed delay in the synaptic process and long asynaptic regions during pachytene. In this species, γH2AX was recorded only at the chromosome ends during early stages of prophase I; in metaphase I, bivalents and quadrivalents of T. maranhensis exhibited binding to microtubules along their entire length, while in metaphase II/anaphase II transition, spindle fibers interacted only with telomeric regions. Regarding T. silvestris, genes involved in the recombination process were transcribed in ovaries, testes and embryos, without significant difference between these tissues. The expression of these genes during T. silvestris achiasmatic meiosis is discussed in the present study. The absence of meiotic inactivation by γH2AX and holo/telokinetic behavior of the chromosomes are important factors for the maintenance of the quadrivalent in T. maranhensis and the normal continuation of the meiotic cycle in this species.
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