Systemic toxicity of snake venom metalloproteinases: Multi-omics analyses of kidney and blood plasma disturbances in a mouse model.

Snakebite envenomation is classified as a Neglected Tropical Disease. Bothrops jararaca venom induces kidney injury and coagulopathy. HF3, a hemorrhagic metalloproteinase of B. jararaca venom, participates in the envenomation pathogenesis. We evaluated the effects of HF3 in mouse kidney and blood plasma after injection in the thigh muscle, mimicking a snakebite. Transcriptomic analysis showed differential expression of 31 and 137 genes related to kidney pathology after 2 h and 6 h, respectively. However, only subtle changes were observed in kidney proteome, with differential abundance of 15 proteins after 6 h, including kidney injury markers. N-terminomic analysis of kidney proteins showed 420 proteinase-generated peptides compatible with meprin specificity, indicating activation of host proteinases. Plasma analysis revealed differential abundance of 90 and 219 proteins, respectively, after 2 h and 6 h, including coagulation-cascade and complement-system components, and creatine-kinase, whereas a semi-specific search of N-terminal peptides indicated activation of endogenous proteinases. HF3 promoted host reactions, altering the gene expression and the proteolytic profile of kidney tissue, and inducing plasma proteome imbalance driven by changes in abundance and proteolysis. The overall response of the mouse underscores the systemic action of a hemorrhagic toxin that transcends local tissue damage and is related to known venom-induced systemic effects.

Multiomics Profiling of Toxins in the Venom of the Amazonian Spider Acanthoscurria juruenicola.

Acanthoscurria juruenicola is an Amazonian spider described for the first time almost a century ago. However, little is known about their venom composition. Here, we present a multiomics characterization of A. juruenicola venom by a combination of transcriptomics, proteomics, and peptidomics approaches. Transcriptomics of female venom glands resulted in 93,979 unique assembled mRNA transcript encoding proteins. A total of 92 proteins were identified in the venom by mass spectrometry, including 14 mature cysteine-rich peptides (CRPs). Quantitative analysis showed that CRPs, cysteine-rich secretory proteins, metalloproteases, carbonic anhydrases, and hyaluronidase comprise >90% of the venom proteome. Relative quantification of venom toxins was performed by DIA and DDA, revealing converging profiles of female and male specimens by both methods. Biochemical assays confirmed the presence of active hyaluronidases, phospholipases, and proteases in the venom. Moreover, the venom promoted in vivo paralytic activities in crickets, consistent with the high concentration of CRPs. Overall, we report a comprehensive analysis of the arsenal of toxins of A. juruenicola and highlight their potential biotechnological and pharmacological applications. Mass spectrometry data were deposited to the ProteomeXchange Consortium via the PRIDE repository with the dataset identifier PXD013149 and via the MassIVE repository with the dataset identifier MSV000087777.

Recombinant Production and Characterization of a New Toxin from Cryptops iheringi Centipede Venom Revealed by Proteome and Transcriptome Analysis.

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.

Rondonin: antimicrobial properties and mechanism of action.

Infectious diseases are among the major causes of death in the human population. A wide variety of organisms produce antimicrobial peptides (AMPs) as part of their first line of defense. A peptide from Acanthoscurria rondoniae plasma, rondonin-with antifungal activity, a molecular mass of 1236 Da and primary sequence IIIQYEGHKH-was previously studied (UniProt accession number B3EWP8). It showed identity with the C terminus of subunit 'D' of the hemocyanin of the Aphonopelma hentzi spider. This result led us to propose a new pathway of the immune system of arachnids that suggests a new function to hemocyanin: production of antimicrobial peptides. Rondonin does not interact with model membranes and was able to bind to yeast nucleic acids but not bacteria. It was not cytotoxic against mammalian cells. The antifungal activity of rondonin is pH-dependent and peaks at pH ˜ 4-5. The peptide presents synergism with gomesin (spider hemocyte antimicrobial peptide-UniProtKB-P82358) against human yeast pathogens, suggesting a new potential alternative treatment option. Antiviral activity was detected against RNA viruses, measles, H1N1, and encephalomyocarditis. This is the first report of an arthropod hemocyanin fragment with activity against human viruses. Currently, it is vital to invest in the search for natural and synthetic antimicrobial compounds that, above all, present alternative mechanisms of action to first-choice antimicrobials.

Integrative multiomics analysis of Premolis semirufa caterpillar venom in the search for molecules leading to a joint disease.

The joint disease called pararamosis is an occupational disease caused by accidental contact with bristles of the caterpillar Premolis semirufa. The chronic inflammatory process narrows the joint space and causes alterations in bone structure and cartilage degeneration, leading to joint stiffness. Aiming to determine the bristle components that could be responsible for this peculiar envenomation, in this work we have examined the toxin composition of the caterpillar bristles extract and compared it with the differentially expressed genes (DEGs) in synovial biopsies of patients affected with rheumatoid arthritis (RA) and osteoarthritis (OA). Among the proteins identified, 129 presented an average of 63% homology with human proteins and shared important conserved domains. Among the human homologous proteins, we identified seven DEGs upregulated in synovial biopsies from RA or OA patients using meta-analysis. This approach allowed us to suggest possible toxins from the pararama bristles that could be responsible for starting the joint disease observed in pararamosis. Moreover, the study of pararamosis, in turn, may lead to the discovery of specific pharmacological targets related to the early stages of articular diseases.

A Multiomics Approach Unravels New Toxins With Possible In Silico Antimicrobial, Antiviral, and Antitumoral Activities in the Venom of Acanthoscurria rondoniae.

The Araneae order is considered one of the most successful groups among venomous animals in the world. An important factor for this success is the production of venoms, a refined biological fluid rich in proteins, short peptides and cysteine-rich peptides (CRPs). These toxins may present pharmacologically relevant biological actions, as antimicrobial, antiviral and anticancer activities, for instance. Therefore, there is an increasing interest in the exploration of venom toxins for therapeutic reasons, such as drug development. However, the process of peptide sequencing and mainly the evaluation of potential biological activities of these peptides are laborious, considering the low yield of venom extraction and the high variability of toxins present in spider venoms. Here we show a robust methodology for identification, sequencing, and initial screening of potential bioactive peptides found in the venom of Acanthoscurria rondoniae. This methodology consists in a multiomics approach involving proteomics, peptidomics and transcriptomics analyses allied to in silico predictions of antibacterial, antifungal, antiviral, and anticancer activities. Through the application of this strategy, a total of 92,889 venom gland transcripts were assembled and 84 novel toxins were identified at the protein level, including seven short peptides and 10 fully sequenced CRPs (belonging to seven toxin families). In silico analysis suggests that seven CRPs families may have potential antimicrobial or antiviral activities, while two CRPs and four short peptides are potentially anticancer. Taken together, our results demonstrate an effective multiomics strategy for the discovery of new toxins and in silico screening of potential bioactivities. This strategy may be useful in toxin discovery, as well as in the screening of possible activities for the vast diversity of molecules produced by venomous animals.

Modulation of stress and immune response by Amblyomin-X results in tumor cell death in a horse melanoma model.

We have investigated Amblyomin-X-treated horse melanomas to better understand its mode of action through transcriptome analysis and the in vivo model. Amblyomin-X is a Kunitz-type homologous protein that selectively leads to the death of tumor cells via ER stress and apoptosis, currently under investigation as a new drug candidate for cancer treatment. Melanomas are immunogenic tumors, and a better understanding of the immune responses is warranted. Equine melanomas are spontaneous and not so aggressive as human melanomas are, as this study shows that the in vivo treatment of encapsulated horse melanoma tumors led to a significant reduction in the tumor size or even the complete disappearance of the tumor mass through intratumoral injections of Amblyomin-X. Transcriptome analysis identified ER- and mitochondria-stress, modulation of the innate immune system, apoptosis, and possibly immunogenic cell death activation. Interactome analysis showed that Amblyomin-X potentially interacts with key elements found in transcriptomics. Taken together, Amblyomin-X modulated the tumor immune microenvironment in different ways, at least contributing to induce tumor cell death.

HIV-1 genetic diversity and divergence and its correlation with disease progression among antiretroviral naïve recently infected individuals.

HIV-1 genetic diversity evolution was deeply characterized during the first year of infection among recently-infected patients using deep sequencing technology and correlated with disease progression surrogate markers. RNA and DNA samples from twenty-five individuals (13 female) encoding the protease and reverse transcriptase regions of the pol gene, and the V3 region of the env gene were evaluated at recent infection and during established infection. Infection by a unique HIV-1 strain was inferred in 70.1% of the individuals, with no differences between genders. Infections by multiple strains were associated with higher viral loads and faster CD4+ T cell declines. Either low or high levels of viral loads accompanied low levels of genetic diversity and lower selective pressure. With massive sequence data from 3 distinct genomic HIV-1 regions from plasma and PBMCs over time, we propose a model for HIV-1 genetic diversity, which correlates to basal viral loads of patients.

Serrulin: A Glycine-Rich Bioactive Peptide from the Hemolymph of the Yellow Tityus serrulatus Scorpion.

Antimicrobial peptides (AMPs) are small molecules, which have a potential use as antibiotic or pharmacological tools. In chelicerate organisms, such as scorpions, these molecules constitute an alternative defense system against microorganisms. The aim of this work was to identify AMPs in the hemolymph of the Tityus serrulatus scorpion. Fractions of plasma and hemocytes were subjected to high-performance liquid chromatography (HPLC) and then analyzed to determine their activity in inhibiting microbial growth. One of the fractions from the hemocytes presents antimicrobial activity against microorganisms, such as Gram-negative and Gram-positive bacteria, fungi, and yeast. These fractions were analyzed by mass spectrometry, and a fragment of 3564 Da. was identified. The peptide was called serrulin, because it is derived from the species T. serrulatus. A comparison of the amino acid sequence of serrulin with databases shows that it has a similarity to the glycine-rich peptides described in Cupienius salai and Acanthoscurria gomesiana (spiders). Furthermore, serrulin has no hemolytic activity against human erythrocytes. While the presence of AMPs in T. serrulatus venom has been described in other works, this is the first work to characterize the presence of these molecules in the hemolymph (hemocytes) of this species and show its potential use as an alternative to conventional antibiotics against different species of microorganisms.

Bottom-Up Proteomic Analysis of Polypeptide Venom Components of the Giant Ant Dinoponera Quadriceps.

Ant species have specialized venom systems developed to sting and inoculate a biological cocktail of organic compounds, including peptide and polypeptide toxins, for the purpose of predation and defense. The genus Dinoponera comprises predatory giant ants that inoculate venom capable of causing long-lasting local pain, involuntary shaking, lymphadenopathy, and cardiac arrhythmias, among other symptoms. To deepen our knowledge about venom composition with regard to protein toxins and their roles in the chemical-ecological relationship and human health, we performed a bottom-up proteomics analysis of the crude venom of the giant ant D. quadriceps, popularly known as the "false" tocandiras. For this purpose, we used two different analytical approaches: (i) gel-based proteomics approach, wherein the crude venom was resolved by denaturing sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and all protein bands were excised for analysis; (ii) solution-based proteomics approach, wherein the crude venom protein components were directly fragmented into tryptic peptides in solution for analysis. The proteomic data that resulted from these two methodologies were compared against a previously annotated transcriptomic database of D. quadriceps, and subsequently, a homology search was performed for all identified transcript products. The gel-based proteomics approach unequivocally identified nine toxins of high molecular mass in the venom, as for example, enzymes [hyaluronidase, phospholipase A1, dipeptidyl peptidase and glucose dehydrogenase/flavin adenine dinucleotide (FAD) quinone] and diverse venom allergens (homologous of the red fire ant Selenopsis invicta) and venom-related proteins (major royal jelly-like). Moreover, the solution-based proteomics revealed and confirmed the presence of several hydrolases, oxidoreductases, proteases, Kunitz-like polypeptides, and the less abundant inhibitor cysteine knot (ICK)-like (knottin) neurotoxins and insect defensin. Our results showed that the major components of the D. quadriceps venom are toxins that are highly likely to damage cell membranes and tissue, to cause neurotoxicity, and to induce allergic reactions, thus, expanding the knowledge about D. quadriceps venom composition and its potential biological effects on prey and victims.

Systems analysis of subjects acutely infected with the Chikungunya virus.

The largest ever recorded epidemic of the Chikungunya virus (CHIKV) broke out in 2004 and affected four continents. Acute symptomatic infections are typically associated with the onset of fever and often debilitating polyarthralgia/polyarthritis. In this study, a systems biology approach was adopted to analyze the blood transcriptomes of adults acutely infected with the CHIKV. Gene signatures that were associated with viral RNA levels and the onset of symptoms were identified. Among these genes, the putative role of the Eukaryotic Initiation Factor (eIF) family genes and apolipoprotein B mRNA editing catalytic polypeptide-like (APOBEC3A) in the CHIKV replication process were displayed. We further compared these signatures with signatures induced by the Dengue virus infection and rheumatoid arthritis. Finally, we demonstrated that the CHIKV in vitro infection of murine bone marrow-derived macrophages induced IL-1 beta production in a mechanism that is significantly dependent on the inflammasome NLRP3 activation. The observations provided valuable insights into virus-host interactions during the acute phase and can be instrumental in the investigation of new and effective therapeutic interventions.

An integrated analysis of mRNA and sRNA transcriptional profiles in Coffea arabica L. roots: insights on nitrogen starvation responses.

Coffea arabica L. is an important agricultural commodity, accounting for 60% of traded coffee worldwide. Nitrogen (N) is a macronutrient that is usually limiting to plant yield; however, molecular mechanisms of plant acclimation to N limitation remain largely unknown in tropical woody crops. In this study, we investigated the transcriptome of coffee roots under N starvation, analyzing poly-A+ libraries and small RNAs. We also evaluated the concentration of selected amino acids and N-source preferences in roots. Ammonium was preferentially taken up over nitrate, and asparagine and glutamate were the most abundant amino acids observed in coffee roots. We obtained 34,654 assembled contigs by mRNA sequencing, and validated the transcriptional profile of 12 genes by RT-qPCR. Illumina small RNA sequencing yielded 8,524,332 non-redundant reads, resulting in the identification of 86 microRNA families targeting 253 genes. The transcriptional pattern of eight miRNA families was also validated. To our knowledge, this is the first catalog of differentially regulated amino acids, N sources, mRNAs, and sRNAs in Arabica coffee roots.

An overview of Phoneutria nigriventer spider venom using combined transcriptomic and proteomic approaches.

Phoneutria nigriventer is one of the largest existing true spiders and one of the few considered medically relevant. Its venom contains several neurotoxic peptides that act on different ion channels and chemical receptors of vertebrates and invertebrates. Some of these venom toxins have been shown as promising models for pharmaceutical or biotechnological use. However, the large diversity and the predominance of low molecular weight toxins in this venom have hampered the identification and deep investigation of the less abundant toxins and the proteins with high molecular weight. Here, we combined conventional and next-generation cDNA sequencing with Multidimensional Protein Identification Technology (MudPIT), to obtain an in-depth panorama of the composition of P. nigriventer spider venom. The results from these three approaches showed that cysteine-rich peptide toxins are the most abundant components in this venom and most of them contain the Inhibitor Cysteine Knot (ICK) structural motif. Ninety-eight sequences corresponding to cysteine-rich peptide toxins were identified by the three methodologies and many of them were considered as putative novel toxins, due to the low similarity to previously described toxins. Furthermore, using next-generation sequencing we identified families of several other classes of toxins, including CAPs (Cysteine Rich Secretory Protein-CRiSP, antigen 5 and Pathogenesis-Related 1-PR-1), serine proteinases, TCTPs (translationally controlled tumor proteins), proteinase inhibitors, metalloproteinases and hyaluronidases, which have been poorly described for this venom. This study provides an overview of the molecular diversity of P. nigriventer venom, revealing several novel components and providing a better basis to understand its toxicity and pharmacological activities.

De novo assembly and annotation of Hyalomma dromedarii tick (Acari: Ixodidae) sialotranscriptome with regard to gender differences in gene expression.

BACKGROUND: Hard ticks are hematophagous ectoparasites characterized by their long-term feeding. The saliva that they secrete during their blood meal is their crucial weapon against host-defense systems including hemostasis, inflammation and immunity. The anti-hemostatic, anti-inflammatory and immune-modulatory activities carried out by tick saliva molecules warrant their pharmacological investigation. The Hyalomma dromedarii Koch, 1844 tick is a common parasite of camels and probably the best adapted to deserts of all hard ticks. Like other hard ticks, the salivary glands of this tick may provide a rich source of many compounds whose biological activities interact directly with host system pathways. Female H. dromedarii ticks feed longer than males, thereby taking in more blood. To investigate the differences in feeding behavior as reflected in salivary compounds, we performed de novo assembly and annotation of H. dromedarii sialotranscriptome paying particular attention to variations in gender gene expression. RESULTS: The quality-filtered Illumina sequencing reads deriving from a cDNA library of salivary glands led to the assembly of 15,342 transcripts. We deduced that the secreted proteins included: metalloproteases, glycine-rich proteins, mucins, anticoagulants of the mandanin family and lipocalins, among others. Expression analysis revealed differences in the expression of transcripts between male and female H. dromedarii that might explain the blood-feeding strategies employed by both genders. CONCLUSIONS: The annotated sialome of H. dromedarii helps understand the interaction of tick-host molecules during blood-feeding and can lead to the discovery of new pharmacologically active proteins of ticks of the genus Hyalomma.

Insights about minority HIV-1 strains in transmitted drug resistance mutation dynamics and disease progression.

Objectives: The presence of minority transmitted drug resistance mutations was assessed using ultra-deep sequencing and correlated with disease progression among recently HIV-1-infected individuals from Brazil. Methods: Samples at baseline during recent infection and 1 year after the establishment of the infection were analysed. Viral RNA and proviral DNA from 25 individuals were subjected to ultra-deep sequencing of the reverse transcriptase and protease regions of HIV-1. Results: Viral strains carrying transmitted drug resistance mutations were detected in 9 out of the 25 patients, for all major antiretroviral classes, ranging from one to five mutations per patient. Ultra-deep sequencing detected strains with frequencies as low as 1.6% and only strains with frequencies >20% were detected by population plasma sequencing (three patients). Transmitted drug resistance strains with frequencies <14.8% did not persist upon established infection. The presence of transmitted drug resistance mutations was negatively correlated with the viral load and with CD4+ T cell count decay. Conclusions: Transmitted drug resistance mutations representing small percentages of the viral population do not persist during infection because they are negatively selected in the first year after HIV-1 seroconversion.

Proteomic endorsed transcriptomic profiles of venom glands from Tityus obscurus and T. serrulatus scorpions.

BACKGROUND: Except for the northern region, where the Amazonian black scorpion, T. obscurus, represents the predominant and most medically relevant scorpion species, Tityus serrulatus, the Brazilian yellow scorpion, is widely distributed throughout Brazil, causing most envenoming and fatalities due to scorpion sting. In order to evaluate and compare the diversity of venom components of Tityus obscurus and T. serrulatus, we performed a transcriptomic investigation of the telsons (venom glands) corroborated by a shotgun proteomic analysis of the venom from the two species. RESULTS: The putative venom components represented 11.4% and 16.7% of the total gene expression for T. obscurus and T. serrulatus, respectively. Transcriptome and proteome data revealed high abundance of metalloproteinases sequences followed by sodium and potassium channel toxins, making the toxin core of the venom. The phylogenetic analysis of metalloproteinases from T. obscurus and T. serrulatus suggested an intraspecific gene expansion, as we previously observed for T. bahiensis, indicating that this enzyme may be under evolutionary pressure for diversification. We also identified several putative venom components such as anionic peptides, antimicrobial peptides, bradykinin-potentiating peptide, cysteine rich protein, serine proteinases, cathepsins, angiotensin-converting enzyme, endothelin-converting enzyme and chymotrypsin like protein, proteinases inhibitors, phospholipases and hyaluronidases. CONCLUSION: The present work shows that the venom composition of these two allopatric species of Tityus are considerably similar in terms of the major classes of proteins produced and secreted, although their individual toxin sequences are considerably divergent. These differences at amino acid level may reflect in different epitopes for the same protein classes in each species, explaining the basis for the poor recognition of T. obscurus venom by the antiserum raised against other species.

Bothrops jararaca accessory venom gland is an ancillary source of toxins to the snake.

In Viperidae snakes, it has been attributed to the main venom gland, a component of the venom gland apparatus, the function of synthesizing all venom toxins and storing them inside a basal-central lumen. However, the role of the accessory gland is still unknown. Here, we analyzed the proteome and the transcriptome of the accessory gland during venom production and secretion cycle. We showed that the accessory gland expresses and synthesizes toxins that are similar to those produced by the main venom gland such as C-type lectin/C-type lectin-like proteins, metalloproteinase, phospholipase A2, cysteine rich secretory protein, nerve growth factor, vascular endothelial growth factor, serine proteinase, and l-amino acid oxidase. Our data have shown that toxin synthesis in the accessory gland is asynchronous when compared to the same process in the venom gland. Moreover, this gland also expresses inhibitors of venom phospholipases A2 and metalloproteinases. Transcriptome analysis showed that the transcripts that correspond to toxins in the accessory gland have a good correlation to the main venom gland transcripts. Therefore, it is proposed that the accessory gland is an ancillary source of toxins to the snake, and provides inhibitors that could control venom toxicity (and integrity) during storage. SIGNIFICANCE: In this study, we propose that the accessory venom gland acts as an important ancillary source of toxins to the snake, in lieu of a depleted main venom gland, and provides inhibiting agents that control venom toxicity (and integrity) during its storage.

Peptidomics of Acanthoscurria gomesiana spider venom reveals new toxins with potential antimicrobial activity.

Acanthoscurria gomesiana is a Brazilian spider from the Theraphosidae family inhabiting regions of Southeastern Brazil. Potent antimicrobial peptides as gomesin and acanthoscurrin have been discovered from the spider hemolymph in previous works. Spider venoms are also recognized as sources of biologically active peptides, however the venom peptidome of A. gomesiana remained unexplored to date. In this work, a MS-based workflow was applied to the investigation of the spider venom peptidome. Data-independent and data-dependent LC-MS/MS acquisitions of intact peptides and of peptides submitted to multiple enzyme digestions, followed by automated chromatographic alignment, de novo analysis, database and homology searches with manual validations showed that the venom is composed by <165 features, with masses ranging from 0.4-15.8kDa. From digestions, 135 peptides were identified from 17 proteins, including three new mature peptides: U1-TRTX-Agm1a, U1-TRTX-Agm2a and U1-TRTX-Agm3a, containing 3, 4 and 3 disulfide bonds, respectively. The toxins U1-TRTX-Agm1a differed by only one amino acid from U1-TRTX-Ap1a from A. paulensis and U1-TRTX-Agm2a was derived from the genicutoxin-D1 precursor from A. geniculata. These toxins have potential applications as antimicrobial agents, as the peptide fraction of A. gomesiana showed activity against Escherichia coli, Enterobacter cloacae and Candida albicans strains. MS data are available via ProteomeXchange Consortium with identifier PXD003884. BIOLOGICAL SIGNIFICANCE: Biological fluids of the Acanthoscurria gomesiana spider are sources of active molecules, as is the case of antimicrobial peptides and acylpolyamines found in the hemolymphs. The venom is also a potential source of toxins with pharmacological and biotechnological applications. However, to our knowledge no A. gomesiana venom toxin structure has been determined to date. Using a combination of high resolution mass spectrometry, transcriptomics and bioinformatics, we employed a workflow to fully sequence, determine the number of disulfide bonds of mature peptides and we found new potential antimicrobial peptides. This workflow is suitable for complete peptide toxin sequencing when handling limited amount of venom samples and can accelerate the discovery of peptides with potential biotechnological applications.

Insights into the Hypertensive Effects of Tityus serrulatus Scorpion Venom: Purification of an Angiotensin-Converting Enzyme-Like Peptidase.

The number of cases of envenomation by scorpions has grown significantly in Brazil since 2007, with the most severe cases being caused by the Tityus serrulatus scorpion. Although envenomed patients mostly suffer neurotoxic manifestations, other symptoms, such as hypertension, cannot be exclusively attributed to neurotoxins. Omics analyses have detected plentiful amounts of metalloproteases in T. serrulatus venom. However, the roles played by these enzymes in envenomation are still unclear. Endeavoring to investigate the functions of scorpion venom proteases, we describe here for the first time an Angiotensin I-Converting Enzyme-like peptidase (ACE-like) purified from T. serrulatus venom. The crude venom cleaved natural and fluorescent substrates and these activities were inhibited by captopril. Regarding the serum neutralization, the scorpion antivenom was more effective at blocking the ACE-like activity than arachnid antivenom, although neither completely inhibited the venom cleavage action, even at higher doses. ACE-like was purified from the venom after three chromatographic steps and its identity was confirmed by mass spectrometric and transcriptomic analyses. Bioinformatics analysis showed homology between the ACE-like transcript sequences from Tityus spp. and human testis ACE. These findings advance our understanding of T. serrulatus venom components and may improve treatment of envenomation victims, as ACE-like may contribute to envenomation symptoms, especially the resulting hypertension.

The complete mitochondrial genome of Bothrops jararaca (Reptilia, Serpentes, Viperidae).

The complete mitochondrial genome, containing 17,526 bp, was determined from the pitviper Bothrops jararaca. It is the first mitogenome for the most medically important genus of snake in Latin America. This mitogenome has common snake mitochondrial features such as a duplicated control region that has nearly identical sequences at two different locations of the mitogenome and a translocation of tRNA-Leu (UUR). Besides, we found a translocation of the tRNA-Pro compared to Colubridae snakes. Finally, an unusual possible duplication containing a tRNA-Phe was observed for the first time and may represent a marker of the genus.