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Venom-induced hemorrhage analysis usually is performed by Minimum Hemorrhagic Dose (MHD), however a similar method can be used to compare venoms with fewer laboratory animals. Our work compared the MHD of five different venoms, with the size of hemorrhagic spot, finding good correlations in the results. Considering the 3Rs principle, we propose the use of the hemorrhagic spot method to compare hemorrhagic activity of snake venoms, rather than using the MHD method, since the first one needs 5 times less animals than the other., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

One of the main clinical manifestations presented by victims of snake bite envenoming are coagulation disorders. Considering that fibrinogen is a key molecule for crosslinked fibrin clot formation, the objective of this work was the quantitative analysis of the fibrinogenolytic activity of snakes of medical importance in Brazil and neutralization by specific antivenom. For this, pools of three genera of medical importance (Bothrops, Crotalus and Lachesis) that are used for the production of antivenom were used, and three pools of species of the genus Bothrops that are not part of the pool for the production of antivenom. The Lachesis pool had the highest fibrinogenolytic activity, even demonstrating partial cleavage (42.9 % consumption) of the fibrinogen gamma chain. The Bothrops genus venom pools have shown subtle variations between them. The Crotalus pool, despite not showing total cleavage of any fibrinogen chain, began cleavage of fibrinogen by the beta chain. The specific antivenoms used were able to delay the cleavage of fibrinogen in all the venoms used, which could be the first step towards implementing previous in vitro tests to analyze the quality of the batches of antivenoms produced, thus potentially reducing the use of animals used in this process., (Copyright © 2024. Published by Elsevier Inc.)

The genus Bothrops are considered Category 1 of medical importance by the World Health Organization, responsible for approximately 85 % of snakebites occurring throughout Brazil. Main factors determining snake venom variations can be genetics, diet, gender, geographic distribution, age, or even seasonality. In this study, we compared the composition of protein profile, biochemical activities, and immunorecognition of toxins present in the venom of eight adults of Bothrops species ( B. alternatus, B. atrox, B. jararaca, B. jararacussu, B. leucurus, B. moojeni, B. neuwiedi and B. pauloensis ). The following methods were used to analyze the venoms: protein dosage; electrophoresis in polyacrylamide gel containing SDS; High Performance Liquid Chromatography - Reverse Phase; enzymatic activities, western blotting and Enzyme Linked Immuno Sorbent Assay. The results show inter and intraspecific differences in the electrophoretic profile. LAAO and PLA 2 activities, in general, were higher in males than females and proteolytic activity was higher in females than males. The bothropic antivenom produced by Instituto Butantan recognized most of the protein bands in all Bothrops species analyzed, with only the regions between 37 and 25 kDa presenting lower intensity. A notable variability in the chromatograms was observed. Bothrops venom demonstrated inter-intraspecific disparities in protein composition and biochemical activity., Competing Interests: The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Thais Almeida de Godoy reports financial support was provided by Sao Paulo State Department for Health Coordination of Science Technology and Strategic Health Supplies. Anita Mitico Tanaka-Azevedo reports was provided by State of Sao Paulo Research Foundation. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2024 The Authors.)

Rattlesnakes belonging to the genus Crotalus are widely distributed throughout the Americas. In Brazil, symptoms commonly associated with envenomation by Crotalus durissus collilineatus include myalgia, rhabdomyolysis, renal failure, neurotoxicity, and progressive paralysis, which are related to the protein composition of this venom. Snake venom composition exhibits compositional variability that may reflect geographic distribution, age, captivity, diet, sex, and even individual genetics. Although seasonality is also considered a possible source of variation, there are few reports of such variability in snake venom. In this work, venoms of the same eight C. durissus collilineatus were extracted every three months for two years, to analyze seasonal changes in composition and activities. To this end, venom composition was analyzed by protein quantification, SDS-PAGE, and HPLC, and the LAAO, PLA 2 and coagulant activities were measured. Venoms of these C. d. collilineatus showed minor seasonal differences in venom activities and no composition differences were found. LAAO and coagulant activities displayed a pattern of seasonal change, while PLA 2 activity seemed to have no seasonality tendency. Also, there are sexual differences, in which males seem to be more stable than females in regard to some activities. Individual variability occurs even in seasonal variation of activities, highlighting the importance of controlling circumstances of venom extraction before comparing results between groups of snakes., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests:Anita Mitico Tanaka Azevedo reports financial support was provided by State of Sao Paulo Research Foundation. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Snakes in the family Elapidae largely produce venoms rich in three-finger toxins (3FTx) that bind to the α 1 subunit of nicotinic acetylcholine receptors (nAChRs), impeding ion channel activity. These neurotoxins immobilize the prey by disrupting muscle contraction. Coral snakes of the genus Micrurus are specialist predators who produce many 3FTx, making them an interesting system for examining the coevolution of these toxins and their targets in prey animals. We used a bio-layer interferometry technique to measure the binding interaction between 15 Micrurus venoms and 12 taxon-specific mimotopes designed to resemble the orthosteric binding region of the muscular nAChR subunit. We found that Micrurus venoms vary greatly in their potency on this assay and that this variation follows phylogenetic patterns rather than previously reported patterns of venom composition. The long-tailed Micrurus tend to have greater binding to nAChR orthosteric sites than their short-tailed relatives and we conclude this is the likely ancestral state. The repeated loss of this activity may be due to the evolution of 3FTx that bind to other regions of the nAChR. We also observed variations in the potency of the venoms depending on the taxon of the target mimotope. Rather than a pattern of prey-specificity, we found that mimotopes modeled after snake nAChRs are less susceptible to Micrurus venoms and that this resistance is partly due to a characteristic tryptophan → serine mutation within the orthosteric site in all snake mimotopes. This resistance may be part of a Red Queen arms race between coral snakes and their prey., (© 2024. The Author(s).)

In this work, we compared the biochemical and toxicological profiles of venoms from an adult female specimen of Lachesis muta rhombeata (South American bushmaster) and her seven offspring born in captivity, based on SDS-PAGE, RP-HPLC, enzymatic, coagulant, and hemorrhagic assays. Although adult and juvenile venoms showed comparable SDS-PAGE profiles, juveniles lacked some chromatographic peaks compared with adult venom. Adult venom had higher proteolytic (caseinolytic) activity than juvenile venoms (p < 0.05), but there were no significant inter-venom variations in the esterase, PLA 2 , phosphodiesterase and L-amino acid oxidase (LAAO) activities, although the latter activity was highly variable among the venoms. Juveniles displayed higher coagulant activity on human plasma, with a minimum coagulant dose ∼42% lower than the adult venom (p < 0.05), but there were no age-related differences in thrombin-like activity. Adult venom was more fibrinogenolytic (based on the rate of fibrinogen chain degradation) and hemorrhagic than juvenile venoms (p < 0.05). The effective dose of Bothrops/Lachesis antivenom (produced by the Instituto Butantan) needed to neutralize the coagulant activity was ∼57% greater for juvenile venoms (p < 0.05), whereas antivenom did not attenuate the thrombin-like activity of juvenile and adult venoms. Antivenom significantly reduced the hemorrhagic activity of adult venom (400 μg/kg, i. d.), but not that of juvenile venoms. Overall, these data indicate a compositional and functional ontogenetic shift in L. m. rhombeata venom., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

In Brazil, the genus Bothrops is responsible for most ophidian accidents. Snake venoms have a wide variety of proteins and peptides exhibiting a broad repertoire of pharmacological and toxic effects that elicit systemic injury and characteristic local effects. The snakes' natural resistance to envenomation caused by the presence of inhibitory compounds on their plasma have been extensively studied. However, the presence of these inhibitors in different developmental stages is yet to be further discussed. The aim of this study was to evaluate the ontogeny of Bothrops jararaca plasma inhibitor composition and, to this end, plasma samples of B. jararaca were obtained from different developmental stages (neonates, youngs, and adults) and sexes (female and male). SDS-PAGE, Western blotting, affinity chromatography, and mass spectrometry were performed to analyze the protein profile and interaction between B. jararaca plasma and venom proteins. In addition, the presence of γBjPLI, a PLA2 inhibitor previously identified and characterized in B. jararaca serum, was confirmed by Western blotting. According to our results, 9-17% of plasma proteins were capable of binding to venom proteins in the three developmental stages. The presence of different endogenous inhibitors and, more specifically, different PLA2 inhibitor (PLI) classes and antihemorrhagic factors were confirmed in specimens of B. jararaca from newborn by mass spectrometry. For the first time, the αPLI and βPLI were detected in B. jararaca plasma, although low or no ontogenetic and sexual correlation were found. The γPLI were more abundant in adult female, than in neonate and young female, but similar to neonate, young and adult male according to the results of mass spectrometry analysis. Our results suggest that there are proteins in the plasma of these animals that can help counteract the effects of self-envenomation from birth., Competing Interests: The authors have declared that no competing interests exist., (Copyright: © 2024 Serino-Silva et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.)

Snake venoms are known to be major sources of peptides with different pharmacological properties. In this study, we comprehensively explored the venom peptidomes of three specimens of Lachesismuta, the largest venomous snake in South America, using mass spectrometry techniques. The analysis revealed 19 main chromatographic peaks common to all specimens. A total of 151 peptides were identified, including 69 from a metalloproteinase, 58 from the BPP-CNP precursor, and 24 from a l-amino acid oxidase. To our knowledge, 126 of these peptides were reported for the first time in this work, including a new SVMP-derived peptide fragment, Lm-10a. Our findings highlight the dynamic nature of toxin maturation in snake venoms, driven by proteolytic processing, post-translational modifications, and cryptide formation., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Snakebite is a globally neglected tropical disease, with coagulation disturbances being the primary pathology of many deadly snake venoms. Age-related differences in human plasma have been abundantly reported, yet the effect that these differences pose regarding snakebite is largely unknown. We tested for differences in coagulotoxic effects (via clotting time) of multiple snake venoms upon healthy human adult (18+) and paediatric (median 3.3 years old) plasma in vivo and compared these effects to the time it takes the plasmas to clot without the addition of venom (the spontaneous clotting time). We tested venoms from 15 medically significant snake species (from 13 genera) from around the world with various mechanisms of coagulotoxic actions, across the three broad categories of procoagulant, pseudo-procoagulant, and anticoagulant, to identify any differences between the two plasmas in their relative pathophysiological vulnerability to snakebite. One procoagulant venom ( Daboia russelii , Russell's Viper) produced significantly greater potency on paediatric plasma compared with adult plasma. In contrast, the two anticoagulant venoms ( Pseudechis australis , Mulga Snake; and Bitis cornuta , Many-horned Adder) were significantly more potent on adult plasma. All other procoagulant venoms and all pseudo-procoagulant venoms displayed similar potency across both plasmas. Our preliminary results may inform future studies on the effect of snake venoms upon plasmas from different age demographics and hope to reduce the burden of snakebite upon society.

This study investigated the antineoplastic effects of crotoxin isolated from snake venom of the South American Crotalus durissus terrificus in oral cancer cell lines and in an animal model of chemically induced oral cancer. We analyzed cell viability and death, clonogenic formation, DNA fragmentation, migration assay, and gene expression of MMP2, MMP9, COL1A1, and CASP3. In the animal model, after induction of oral cancer by 4-nitroquinoline-1-oxide carcinogen, mice were treated with crotoxin to investigate its effects on tumor development in tongue and oral mucosa. Crotoxin inhibited cell proliferation, viability, colony formation, and migration, favoring cell death. Furthermore, crotoxin increased caspase-3 expression, decreased Ki-67 protein and mRNA expression of MMP2, MMP9, and COL1A1. Mice treated with crotoxin at 10 μg/kg did not alter biochemical parameters total cholesterol, very-low-density lipoprotein, high-density lipoprotein, liver transaminases, glycemia, creatinine, and urea. Crotoxin treatment significantly reduced the frequency of oral squamous cell carcinoma lesions by 50%. Thus, this study highlights crotoxin as a promising chemotherapeutic substance, considering its effects on controlling the neoplastic cell population, reducing cell migration, and inhibiting tumor development. Clinical studies are necessary to understand better the impact of crotoxin as a potential adjuvant therapeutic agent for oral cancer patients., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Considerable heterogeneity and ontogenetic changes in venom composition have already been observed in different species of snakes within the Viperidae family. Since the venom of young and adult can cause distinct pathological effects and because the antivenom may be less effective in neutralizing envenoming by young snakes compared to adults, it is of paramount importance to understand the ontogenetic variation of snake venom. Thus, the present study aimed to analyze and compare the venom of Bothrops pauloensis snakes, searching for possible influences of ontogeny and sex in their biochemical and biological aspects. The venom of younger individuals was more complex in relation to high molecular mass proteins, with a greater abundance of metalloproteinases, while adults showed a greater abundance of medium and low molecular mass proteins, such as phospholipases A 2 (PLA 2 ), C-type lectins and serine proteases. The antivenom showed better immunorecognition towards the venom of adult snakes than younger ones, in addition to a deficiency in the recognition of medium molecular mass proteins, suggesting the need for an improvement in the antivenom. Younger snakes showed higher coagulant, caseinolytic, and hemorrhagic activity, while adult snakes showed higher L-amino acid oxidase (LAAO) activity and acted faster in lethality. Differences between males and females were observed mainly in the rate of loss of coagulant activity, change in PLA 2 activity and lethality action time. Furthermore, considering only the adult groups, males showed a higher LAAO and thrombin-like activity, while females showed a higher caseinolytic and hyaluronidase activity. With the results obtained in this work, it was possible to conclude that there is an ontogenetic variation in the composition and some activities of the B. pauloensis snake venom, in addition to differences between the venom of males and females, reinforcing that there is an intraspecific variation that may result in different symptoms in their envenoming and, consequently, differences in the response to treatment with the antivenom., (Copyright © 2022. Published by Elsevier Ltd.)

This work compared the presence of phospholipase A 2 inhibitors (PLIs) in the serum of 19 snake species maintained at Instituto Butantan to better understand the mechanisms of venom resistance in snakes and improve the treatment of snakebite. PLI was isolated from blood of 19 snake species by one-step chromatography and identified in all samples, besides its identity was confirmed through the interaction with both phospholipase A 2 and anti-γPLI. These findings highlight the diversity of snake serum PLIs and emphasize the importance of structure-function studies., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Despite coagulotoxicity being a primary weapon for prey capture by Bothrops species (lancehead pit vipers) and coagulopathy being a major lethal clinical effect, a genus-wide comparison has not been undertaken. To fill this knowledge gap, we used thromboelastography to compare 37 venoms, from across the full range of geography, taxonomy, and ecology, for their action upon whole plasma and isolated fibrinogen. Potent procoagulant toxicity was shown to be the main venom effect of most of the species tested. However, the most basal species ( B. pictus ) was strongly anticoagulant; this is consistent with procoagulant toxicity being a novel trait that evolved within Bothrops subsequent to their split from anticoagulant American pit vipers. Intriguingly, two of the arboreal species studied ( B. bilineatus and B. taeniatus ) lacked procoagulant venom, suggesting differential evolutionary selection pressures. Notably, some terrestrial species have secondarily lost the procoagulant venom trait: the Mogi Mirim, Brazil locality of B. alternatus ; San Andres, Mexico locality of B. asper ; B. diporus ; and the São Roque of B. jararaca . Direct action on fibrinogen was extremely variable; this is consistent with previous hypotheses regarding it being evolutionary decoupled due to procoagulant toxicity being the primary prey-capture weapon. However, human patients live long enough for fibrinogen depletion to be clinically significant. The extreme variability may be reflective of antivenom variability, with these results thereby providing a foundation for such future work of clinical relevance. Similarly, the venom diversification trends relative to ecological niche will also be useful for integration with natural history data, to reconstruct the evolutionary pressures shaping the venoms of these fascinating snakes.

The use of venom in predation exerts a corresponding selection pressure for the evolution of venom resistance. One of the mechanisms related to venom resistance in animals (predators or prey of snakes) is the presence of molecules in the blood that can bind venom toxins, and inhibit their pharmacological effects. One such toxin type are venom phospholipase A 2 s (PLA 2 s), which have diverse effects including anticoagulant, myotoxic, and neurotoxic activities. BoaγPLI isolated from the blood of Boa constrictor has been previously shown to inhibit venom PLA 2 s that induced myotoxic and edematogenic activities. Recently, in addition to its previously described and very potent neurotoxic effect, the venoms of American coral snakes (Micrurus species) have been shown to have anticoagulant activity via PLA 2 toxins. As coral snakes eat other snakes as a major part of their diet, neonate Boas could be susceptible to predation by this sympatric species. Thus, this work aimed to ascertain if BoaγPLI provided a protective effect against the anticoagulant toxicity of venom from the model species Micrurus laticollaris in addition to its ability shown previously against other toxin types. Using a STA R Max coagulation analyser robot to measure the effect upon clotting time, and TEG5000 thromboelastographers to measure the effect upon clot strength, we evaluated the ability of BoaγPLI to inhibit M. laticollaris venom. Our results indicate that BoaγPLI is efficient at inhibiting the M. laticollaris anticoagulant effect, reducing the time of coagulation (restoring them closer to non-venom control values) and increasing the clot strength (restoring them closer to non-venom control values). These findings demonstrate that endogenous PLA 2 inhibitors in the blood of non-venomous snakes are multi-functional and provide broad resistance against a myriad of venom PLA 2 -driven toxic effects including coagulotoxicity, myotoxicity, and neurotoxicity. This novel form of resistance could be evidence of selective pressures caused by predation from venomous snakes and stresses the need for field-based research aimed to expand our understanding of the evolutionary dynamics of such chemical arms race., (© 2021. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Is snake venom activity influenced by size? This is a long-standing question that can have important consequences for the treatment of snake envenomation. Ontogenetic shifts in venom composition are a well-documented characteristic of numerous snake species. Although snake venoms can cause a range of pathophysiological disturbances, establishing the coagulotoxic profiles related to such shifts is a justified approach because coagulotoxicity can be deadly, and its neutralisation is a challenge for current antivenom therapy. Thus, we aimed to assess the coagulotoxicity patterns on plasma and fibrinogen produced by B othrops jararacussu venoms from individuals of different sizes and sex, and the neutralisation potential of SAB (anti bothropic serum produced by Butantan Institute). The use of a metalloproteinase inhibitor (Prinomastat) and a serine proteinase inhibitor (AEBSF) enabled us to determine the toxin class responsible for the observed coagulopathy: activity on plasma was found to be metalloprotease driven, while the activity on fibrinogen is serine protease driven. To further explore differences in venom activity, the activation of Factor X and prothrombin as a function of snake size was also evaluated. All the venoms exhibited a potent procoagulant effect upon plasma and were less potent in their pseudo-procoagulant clotting effect upon fibrinogen. On human plasma, the venoms from smaller snakes produced more rapid clotting than the larger ones. In contrast, the venom activity on fibrinogen had no relation with size or sex. The difference in procoagulant potency was correlated with the bigger snakes being proportionally better neutralized by antivenom due to the lower levels of procoagulant toxins, than the smaller. Thus, while the antivenom ultimately neutralized the venoms, proportionally more would be needed for an equal mass of venom from a small snake than a large one. Similarly, the neutralisation by SAB of the pseudo-procoagulant clotting effects was also correlated with relative potency, with the smaller and bigger snakes being neutralized proportional to potency, but with no correlation to size. Thromboelastography (TEG) tests on human and toad plasma revealed that small snakes' venoms acted quicker than large snakes' venom on both plasmas, with the action upon amphibian plasma consistent with smaller snakes taking a larger proportion of anuran prey than adults. Altogether, the ontogenetic differences regarding coagulotoxic potency and corresponding impact upon relative antivenom neutralisation of snakes with different sizes were shown, underscoring the medical importance of investigating ontogenetic changes in order to provide data crucial for evidence-based design of clinical management strategies., Competing Interests: Declaration of Competing Interest The authors report no declarations of interest., (Copyright © 2021 Elsevier B.V. All rights reserved.)

The Brazilian lancehead (Bothrops moojeni) has a wide distribution in Brazil and represents a serious public health hazard. Previous works reported that the symptoms of snakebites caused by B. moojeni juveniles' bites were mainly related to coagulation, while those caused by adults' bites had a more prominent local damage. In this work, we analyzed the venoms of B. moojeni at different life stages to better understand the ontogeny shift in this species. Snakes were grouped by age and sex, and venom pools were formed accordingly. Compositional analyses by one-dimensional electrophoresis (1-DE), chromatography, and mass spectrometry revealed that ontogenetic changes might be mostly related to phospholipase A2 (PLA2) and metalloproteases. Regarding the venoms functional aspect, proteolytic, L-amino acid oxidase, PLA2, and coagulant in vitro activities were assayed, but only the first and the last ones showed age-related changes, with the venom of snakes up to 1 year-old displaying lower proteolytic and higher coagulant activities, while those from 2 years-old onward presented the opposite relation. The venoms of 3 years-old snakes were exceptions to the compositional and functional pattern of adults as both venoms presented profiles similar to neonates. Sex-related differences were observed in specific groups and were not age-related. In vivo experiments (median lethal dose and hemorrhagic activity) were statistically similar between neonates and adults, however we verified that the adult venom killed mice faster comparing to the neonates. All venoms were mostly recognized by the antibothropic serum and displayed similar profiles to 1-DE in western blotting. In conclusion, the Brazilian lancehead venom showed ontogenetic shift in its composition and activities. Furthermore, this change occurred in snakes from 1 to 2 years-old, and interestingly the venom pools from 3 years-old snakes had particular characteristics, which highlights the importance of comprehensive studies to better understand venom variability., Competing Interests: The authors have declared that no competing interests exist.

This short essay pretends to make the reader reflect on the concept of biological mass and on the added value that the determination of this molecular property of a protein brings to the interpretation of evolutionary and translational snake venomics research. Starting from the premise that the amino acid sequence is the most distinctive primary molecular characteristics of any protein, the thesis underlying the first part of this essay is that the isotopic distribution of a protein's molecular mass serves to unambiguously differentiate it from any other of an organism's proteome. In the second part of the essay, we discuss examples of collaborative projects among our laboratories, where mass profiling of snake venom PLA2 across conspecific populations played a key role revealing dispersal routes that determined the current phylogeographic pattern of the species., (© 2021 The Author(s).)

The venom color variation of Crotalus durissus terrificus (Cdt) is attributed to the presence of the toxin L-amino acid oxidase (LAAO). During the venom milking routine of Instituto Butantan, we have noticed that most venoms of captive Cdt specimens show a yellowish color, while most venoms of wild specimens are white. Here we describe a comparative analysis of long-term captive (LTC) and recently wild-caught (RWC) Cdt, focusing on LAAO variation. For the identification of LAAO in individual venoms, four different approaches were employed: evaluation of the enzymatic activity, SDS-PAGE, Western blotting, and ELISA. In addition, mass spectrometry analysis was performed using pooled samples. Although some variation among these methodologies was observed, it was possible to notice that the presence of LAAO was significantly higher in the venom of LTC individuals. LAAO was identified in 60-80% LTC specimens and in only 10-12% of RWC specimens. Furthermore, this enzyme accounts for 5.6% of total venom proteins of LTC Cdt pooled venom, while it corresponds to only 0.7% of RWC Cdt pooled venom. These findings strongly suggest that captive maintenance increases the expression of LAAO in Cdt venom., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Maintenance of snakes at Butantan Institute started in the last century, intending to produce a different antivenom serum to reduce death caused by snakebites. Through a successful campaign coordinated by Vital Brazil, farmers sent venomous snakes to Butantan Institute by the railway lines with no cost. From 1908 to 1962, the snakes were kept in an outdoor serpentarium, where venom extraction was performed every 15 days. During this period, the snake average survival was 15 days. In 1963, the snakes were transferred to an adapted building, currently called Laboratory of Herpetology (LH), to be maintained in an intensive system. Although the periodicity of venom extraction remained the same, animal average survival increased to two months. With the severe serum crisis in 1983, the Ministry of Health financed remodeling for the three public antivenom producers, and with this support, the LH could be improved. Air conditioning and exhausting systems were installed in the rooms, besides the settlement of critical hygienic-sanitary managements to increase the welfare of snakes. In the early 1990s, snake survival was ten months. Over the years to the present day, several improvements have been made in the intensive serpentarium, as the establishment of two quarantines, feeding with thawed rodents, an interval of two months between venom extraction routines, and monitoring of snake health through laboratory tests. With these new protocols, average snake survival increased significantly, being eight years for the genus Bothrops , ten years for genus Crotalus and Lachesis, and four years for the genus Micrurus . Aiming the production of venoms of good quality, respect for good management practices is essential for the maintenance of snakes in captivity. New techniques and efficient management must always be sought to improve animal welfare, the quality of the venom produced, and the safety of those working directly with the venomous snakes., Competing Interests: Competing interests: The authors declare that they have no competing interests.

Concerning snake venoms, numerous authors worked with different species of Bothrops focusing on the ontogeny of these animals. However, according to PubMed database, no results on studies related to Bothrops jararacussu ontogeny were displayed until now. This fact led us to develop a greater interest in the venom ontogenetic variability of this species, which is little explored so far. Among snakes of the genus Bothrops, B. jararacussu was previously described as the one with highest myotoxic activity. Another peculiarity was also observed in its venom: a low rate of immunogenicity. In addition, its activity is not efficiently neutralized by the specific antibothropic serum. Considering these particularities, we performed an ontogenetic study of B. jararacussu using venom samples from newborns of the same litter (<6 months) and adults (>24 months). Our results identified two distinct profiles in the venom of these animals: young individuals with little PLA 2 K-49 and more proteases; and adults with a lot of the same myotoxic PLA 2, but less proteases. The HPLC and SDS-PAGE profiles corroborated our findings. Adults showed more hemorrhagic activity in vivo than juveniles, while adult males showed less activity when compared to females. In vivo myotoxicity activity was higher in adults than in juveniles. Immune recognition assays showed different results for the distinct venom., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Background: Lack of complete genomic data of Bothrops jararaca impedes molecular biology research focusing on biotechnological applications of venom gland components. Identification of full-length coding regions of genes is crucial for the correct molecular cloning design., Methods: RNA was extracted from the venom gland of one adult female specimen of Bothrops jararaca . Deep sequencing of the mRNA library was performed using Illumina NextSeq 500 platform. De novo assembly of B. jararaca transcriptome was done using Trinity. Annotation was performed using Blast2GO. All predicted proteins after clustering step were blasted against non-redundant protein database of NCBI using BLASTP. Metabolic pathways present in the transcriptome were annotated using the KAAS-KEGG Automatic Annotation Server. Toxins were identified in the B. jararaca predicted proteome using BLASTP against all protein sequences obtained from Animal Toxin Annotation Project from Uniprot KB/Swiss-Pro database. Figures and data visualization were performed using ggplot2 package in R language environment., Results: We described the in-depth transcriptome analysis of B. jararaca venom gland, in which 76,765 de novo assembled isoforms, 96,044 transcribed genes and 41,196 unique proteins were identified. The most abundant transcript was the zinc metalloproteinase-disintegrin-like jararhagin. Moreover, we identified 78 distinct functional classes of proteins, including toxins, inhibitors and tumor suppressors. Other venom proteins identified were the hemolytic lethal factors stonustoxin and verrucotoxin., Conclusion: It is believed that the application of deep sequencing to the analysis of snake venom transcriptomes may represent invaluable insight on their biotechnological potential focusing on candidate molecules., Competing Interests: Competing interests: The authors declare no potential competing interests.

The South American rattlesnake Crotalus durissus spp has a wide geographic distribution in Brazil. Although responsible for only a low proportion of ophidian accidents, it is considered one of the most medically important species of venomous snakes due to the high mortality rate (1.87%). Snake venom is a complex phenotype commonly subjected to individual intraspecific, ontogenetic and geographic variability. Compositional differences in pooled venom used in the immunization process may impact the efficacy of the antivenom. In order to assure standardized high-quality antivenom, the potency of each Brazilian crotalic antivenom batch is determined against the 'Brazilian Crotalic Reference Venom' (BCRV). BCRV is produced by Instituto Butantan using venom obtained from the first milking of recently wild-caught C. d. terrificus specimens brought to the Institute. The decrease in the number of snake donations experienced in recent years can become a threat to the production of future batches of BCRV. To evaluate the feasibility of using venom from long-term captive animals in the formulation of BCRV, we have compared the proteomic, biochemical and biological profiles of C. d. terrificus venom pooled from captive specimens (CVP- captive venom pool) and BCRV. Electrophoretic and venomics analyses revealed a very similar venom composition profile, but also certain differences in toxins abundance, with some low abundant protein families found only in BCRV. Enzymatic (L-amino acid oxidase, phospholipase A 2 and proteolytic) and biological (myotoxic and coagulant) activities showed higher values in CVP than in BCRV. CVP also possessed slightly higher lethal effect, although the Instituto Butantan crotalic antivenom showed equivalent potency neutralizing BCRV and CVP. Our results strongly suggest that venom from long-term captive C. d. terrificus might be a valid alternative to generate an immunization mixture of equivalent quality to the currently in use reference venom., (Copyright © 2020. Published by Elsevier Ltd.)

Background: Variability in snake venoms is a well-studied phenomenon. However, sex-based variation of Bothrops atrox snake venom using siblings is poorly investigated. Bothrops atrox is responsible for the majority of snakebite accidents in the Brazilian Amazon region. Differences in the venom composition of Bothrops genus have been linked to several factors such as ontogeny, geographical distribution, prey preferences and sex. Thus, in the current study, venom samples of Bothrops atrox male and female siblings were analyzed in order to compare their biochemical and biological characteristics., Methods: Venoms were collected from five females and four males born from a snake captured from the wild in São Bento (Maranhão, Brazil), and kept in the Laboratory of Herpetology of Butantan Intitute. The venoms were analyzed individually and as a pool of each gender. The assays consisted in protein quantification, 1-DE, mass spectrometry, proteolytic, phospholipase A 2 , L-amino acid oxidase activities, minimum coagulant dose upon plasma, minimum hemorrhagic dose and lethal dose 50%., Results: Electrophoretic profiles of male's and female's venom pools were quite similar, with minor sex-based variation. Male venom showed higher LAAO, PLA 2 and hemorrhagic activities, while female venom showed higher coagulant activity. On the other hand, the proteolytic activities did not show statistical differences between pools, although some individual variations were observed. Meanwhile, proteomic profile revealed 112 different protein compounds; of which 105 were common proteins of female's and male's venom pools and seven were unique to females. Despite individual variations, lethality of both pools showed similar values., Conclusion: Although differences between female and male venoms were observed, our results show that individual variations are significant even between siblings, highlighting that biological activities of venoms and its composition are influenced by other factors beyond gender., Competing Interests: Competing interests: The authors declare that they have no competing interests.

Background: Bothrops atrox is known to be the pit viper responsible for most snakebites and human fatalities in the Amazon region. It can be found in a wide geographical area including northern South America, the east of Andes and the Amazon basin. Possibly, due to its wide distribution and generalist feeding, intraspecific venom variation was reported by previous proteomics studies. Sex-based and ontogenetic variations on venom compositions of Bothrops snakes were also subject of proteomic and peptidomic analysis. However, the venom peptidome of B. atrox remains unknown., Methods: We conducted a mass spectrometry-based analysis of the venom peptides of individual male and female specimens combining bottom-up and top-down approaches., Results: We identified in B. atrox a total of 105 native peptides in the mass range of 0.4 to 13.9 kDa. Quantitative analysis showed that phospholipase A 2 and bradykinin potentiating peptides were the most abundant peptide families in both genders, whereas disintegrin levels were significantly increased in the venoms of females. Known peptides processed at non-canonical sites and new peptides as the Ba1a, which contains the SVMP BATXSVMPII1 catalytic site, were also revealed in this work., Conclusion: The venom peptidomes of male and female specimens of B. atrox were analyzed by mass spectrometry-based approaches in this work. The study points to differences in disintegrin levels in the venoms of females that may result in distinct pathophysiology of envenomation. Further research is required to explore the potential biological implications of this finding., Competing Interests: Competing interests: The authors declare that they have no competing interests.

Various factors, such as geographical origin, climate, sex, age and diet can influence the composition and pathophysiological activities of snake venoms. In this study, we examined the sexual and ontogenetic variations in the venom of Bothrops leucurus, a pitviper responsible for more than 80% of the snakebites in the state of Bahia, northeastern Brazilian. The venoms of 31 snakes were pooled according to sex and age (young, adult and old) and screened by SDS-PAGE (in reducing and non-reducing conditions), reverse-phase high performance liquid chromatography (RP-HPLC), gelatin zymography, and immunoblotting with therapeutic bothropic antivenom (BAV) from the Instituto Butantan. The electrophoretic and chromatographic profiles showed intraspecific ontogenetic variation, whereas sexual variations were less evident. All venoms showed gelatinolytic activity associated with 50-75 kDa protein bands. In addition, all venoms, regardless of the snakes' sex and age, cross-reacted to similar extents with BAV. Our findings show that B. leucurus venom changes during ontogenetic development and demonstrate sexual differences in its composition, indicating differences in biological activity., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Background: South American rattlesnakes are represented in Brazil by a single species, Crotalus durissus , which has public health importance due to the severity of its envenomation and to its wide geographical distribution. The species is subdivided into several subspecies, but the current classification is controversial. In Brazil, the venoms of C. d. terrificus and C. d. collilineatus are used for hyperimmunization of horses for antivenom production, even though the distinction of these two subspecies are mostly by their geographical distribution. In this context, we described a comparative compositional and functional characterization of individual C. d. collilineatus and C. d. terrificus venoms from three Brazilian states., Methods: We compared the compositional patterns of C. d. terrificus and C. d. collilineatus individual venoms by 1-DE and RP-HPLC. For functional analyzes, the enzymatic activities of PLA 2 , LAAO, and coagulant activity were evaluated. Finally, the immunorecognition of venom toxins by the crotalic antivenom produced at Butantan Institute was evaluated using Western blotting., Results: The protein profile of individual venoms from C. d. collilineatus and C. d. terrificus showed a comparable overall composition, despite some intraspecific variation, especially regarding crotamine and LAAO. Interestingly, HPLC analysis showed a geographic pattern concerning PLA 2 . In addition, a remarkable intraspecific variation was also observed in PLA 2 , LAAO and coagulant activities. The immunorecognition pattern of individual venoms from C. d. collilineatus and C. d. terrificus by crotalic antivenom produced at Butantan Institute was similar., Conclusions: The results highlighted the individual variability among the venoms of C. durissus ssp. specimens. Importantly, our data point to a geographical variation of C. durissus ssp. venom profile, regardless of the subspecies, as evidenced by PLA 2 isoforms complexity, which may explain the increase in venom neurotoxicity from Northeastern through Southern Brazil reported for the species., Competing Interests: Competing interests: The authors declare that they have no competing interests.

We report a structural and functional proteomics characterization of venoms of the two subspecies ( Bothrops bilineatus bilineatus and B. b. smaragdinus ) of the South American palm pit viper from the Brazilian state of Rondônia and B. b. smaragdinus from Perú. These poorly known arboreal and mostly nocturnal generalist predators are widely distributed in lowland rainforests throughout the entire Amazon region, where they represent an important cause of snakebites. The three B. bilineatus spp. venom samples exhibit overall conserved proteomic profiles comprising components belonging to 11 venom protein classes, with PIII (34-40% of the total venom proteins) and PI (8-18%) SVMPs and their endogenous tripeptide inhibitors (SVMPi, 8-10%); bradykinin-potentiating-like peptides (BBPs, 10.7-15%); snake venom serine proteinases (SVSP, 5.5-14%); C-type lectin-like proteins (CTL, 3-10%); phospholipases A 2 (PLA 2 , 2.8-7.6%); cysteine-rich secretory proteins (CRISP, 0.9-2.8%); l-amino acid oxidases (LAO, 0.9-5%) representing the major components of their common venom proteomes. Comparative analysis of the venom proteomes of the two geographic variants of B. b. smaragdinus with that of B. b. bilineatus revealed that the two Brazilian taxa share identical molecules between themselves but not with Peruvian B. b. smaragdinus , suggesting hybridization between the geographically close, possibly sympatric, Porto Velho (RO, BR) B. b. smaragdinus and B. b. bilineatus parental populations. However, limited sampling does not allow determining the frequency of this event. The toxin arsenal of the South American palm pit vipers may account for the in vitro recorded collagenolytic, caseinolytic, PLA 2 , l-amino acid oxidase, thrombin-like and factor X-activating activities, and the clinical features of South American palm pit viper envenomings, i.e., local and progressively ascending pain, shock and loss of consciousness, spontaneous bleeding, and profound coagulopathy. The remarkable cross-reactivity of the Brazilian pentabothropic SAB antivenom toward the heterologous B. b. bilineatus venom suggests that the paraspecific antigenic determinants should have been already present in the venom of the last common ancestor of the Bothrops ″ jararaca ″ and ″ taeniatus ″ clades, about 8.5 Mya in the mid-late Miocene epoch of the Cenozoic era. The mass spectrometry proteomics data have been deposited to the ProteomeXchange Consortium via the PRIDE partner repository with the data set identifiers PXD020043, PXD020026, and PXD020013.

Background: Crotalus durissus is considered one of the most important species of venomous snakes in Brazil, due to the high mortality of its snakebites. The venom of Crotalus durissus contains four main toxins: crotoxin, convulxin, gyroxin and crotamine. Venoms can vary in their crotamine content, being crotamine-negative or -positive. This heterogeneity is of great importance for producing antivenom, due to their different mechanisms of action. The possibility that antivenom produced by Butantan Institute might have a different immunorecognition capacity between crotamine-negative and crotamine-positive C. durissus venoms instigated us to investigate the differences between these two venom groups., Methods: The presence of crotamine was analyzed by SDS-PAGE, western blotting and ELISA, whereas comparison between the two types of venoms was carried out through HPLC, mass spectrometry analysis as well as assessment of antivenom lethality and efficacy., Results: The results showed a variation in the presence of crotamine among the subspecies and the geographic origin of snakes from nature, but not in captive snakes. Regarding differences between crotamine-positive and -negative venoms, some exclusive proteins are found in each pool and the crotamine-negative pool presented more phospholipase A 2 than crotamine-positive pool. This variation could affect the time to death, but the lethal and effective dose were not affected., Conclusion: These differences between venom pools indicate the importance of using both, crotamine-positive and crotamine-negative venoms, to produce the antivenom., Competing Interests: Competing interests: The authors declare that they have no competing interests.

Plasma in several organisms has components that promote resistance to envenomation by inhibiting specific proteins from snake venoms, such as phospholipases A2 (PLA2s). The major hypothesis for inhibitor's presence would be the protection against self-envenomation in venomous snakes, but the occurrence of inhibitors in non-venomous snakes and other animals has opened new perspectives for this molecule. Thus, this study showed for the first time the structural and functional characterization of the PLA2 inhibitor from the Boa constrictor serum (BoaγPLI), a non-venomous snake that dwells extensively the Brazilian territory. Therefore, the inhibitor was isolated from B. constrictor serum, with 0.63% of recovery. SDS-PAGE showed a band at ~25 kDa under reducing conditions and ~20 kDa under non-reducing conditions. Chromatographic analyses showed the presence of oligomers formed by BoaγPLI. Primary structure of BoaγPLI suggested an estimated molecular mass of 22 kDa. When BoaγPLI was incubated with Asp-49 and Lys-49 PLA2 there was no severe change in its dichroism spectrum, suggesting a non-covalent interaction. The enzymatic assay showed a dose-dependent inhibition, up to 48.2%, when BoaγPLI was incubated with Asp-49 PLA2, since Lys-49 PLA2 has a lack of enzymatic activity. The edematogenic and myotoxic effects of PLA2s were also inhibited by BoaγPLI. In summary, the present work provides new insights into inhibitors from non-venomous snakes, which possess PLIs in their plasma, although the contact with venom is unlikely., Competing Interests: The authors have declared that no competing interests exist.

Snake venoms are complex protein mixtures with different biological activities that can act in both their preys and human victims. Many of these proteins play a role in prey capture and in the digestive process of these animals. It is known that some snakes are resistant to the toxicity of their own venom by mechanisms not yet fully elucidated. However, it was observed in the Laboratory of Herpetology of Instituto Butantan that some Bothrops moojeni individuals injured by the same snake species showed mortalities caused by envenoming effects. This study analyzed the biochemical composition of 13 venom and plasma samples from Bothrops moojeni specimens to assess differences in their protein composition. Application of sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) showed distinct venom protein profiles, but very homogeneous plasma profiles. Western Blotting (WB) was performed with plasma samples, which were submitted to incubation with the respective venom. Some individuals showed an immunorecognized band zone around 25 kDa, indicating interaction between the same individual plasma and venom proteins. Crossed-WB assay using non-self-plasma and venom showed that this variability is due to venom protein composition instead of plasma composition. These venoms presented higher caseinolytic, collagenolytic and coagulant activities than the venoms without these regions recognized by WB. Mass spectrometry analyses performed on two individuals revealed that these individuals present, in addition to higher protein concentrations, other exclusive proteins in their composition. When these same two samples were tested in vivo, the results also showed higher lethality in these venoms, but lower hemorrhagic activity than in the venoms without these regions recognized by WB. In conclusion, some Bothrops moojeni specimens differ in venom composition, which may have implications in envenomation. Moreover, the high individual venom variability found in this species demonstrates the importance to work with individual analyses in studies involving intraspecific venom variability and venom evolution., Competing Interests: The authors have declared that no competing interests exist.

Intraspecific venom variability has been extensively reported in a number of species and is documented to be the result of several factors. However, current evidence for snake venom variability related to captivity maintenance is controversial. Here we report a compositional and functional investigation of individual and pooled venoms from long-term captive (LTC) and recently wild-caught (RWC) B. jararaca snakes. The composition of individual venoms showed a remarkable variability in terms of relative abundance of toxins (evidenced by 1-DE and RP-HPLC), enzymatic activities (proteolytic, PLA 2 , and LAAO) and coagulant activity, even among captive specimens. Thus, no compositional and functional pattern could be established to assign each individual venom to a specific group. Conversely, pooled venom from LTC and RWC snakes showed no significant differences regarding protein composition (characterized by 1-DE and shotgun proteomics), enzymatic activities (proteolytic, PLA 2 and LAAO) and biological function (coagulant, hemorrhagic and lethal activities), except for edematogenic activity, which was more prominent in RWC venom pool. Additionally, both pooled venoms displayed similar immunoreactivity with the bothropic antivenom produced by Instituto Butantan. Taken together, our results highlight the complexity and the high intraspecific variation of B. jararaca venom, that is not influenced at a discernible extent by captivity maintenance., Biological Significance: Bothrops jararaca snakes are one of the main causes of snakebites in Southeastern Brazil. Due to its medical interest, the venom of this species is the most studied and characterized among Brazilian snakes and captive B. jararaca specimens are maintained for long periods of time in our venom production facility. However, knowledge on the influence of captivity maintenance on B. jararaca venom variability is scarce. In this report, we described a high compositional and functional variability of individual venoms from LTC and RWC B. jararaca snakes, which are not observed between LTC and RWC pooled venoms. This intraspecific variability is more likely to be due to genetic/populational differences rather than "captivity vs wild" conditions. In this regard, data generated by the present work support the use of venom from captive and wild snakes for antivenom production and scientific research. Moreover, the data generated by this study highlight the importance of analyzing individual venom samples in studies involving intraspecific venom variability., (Copyright © 2018 Elsevier B.V. All rights reserved.)

The assessment of the capacity of antivenoms to neutralize the lethal activity of snake venoms still relies on traditional rodent in vivo lethality assay. ED 50 and LD 50 assays require large quantities of venoms and antivenoms, and besides leading to animal suffering. Therefore, in vitro tests should be introduced for assessing antivenom neutralizing capacity in intermediary steps of antivenom production. This task is facilitated when one key lethal toxin is identified. A good example is crotoxin, a β-neurotoxin phospholipase A 2 -like toxin that presents anticoagulant activity in vitro and is responsible for the lethality of venoms of Crotalus durissus snakes. By using rotational thromboelastometry, we reported recently one sensitive coagulation assay for assessing relative potency of the anti-bothropic serum in neutralizing procoagulant activity of Bothrops jararaca venom upon recalcified factor-XII-deficient chicken plasma samples (CPS). In this study, we stablished conditions for determining relative potency of four batches of the anti-crotalic serum (ACS) (antagonist) in inactivating crotoxin anticoagulant activity in CPS (target) simultaneously treated with one classical activator of coagulation (agonists). The correlation coefficient (r) between values related the ACS potency in inactivating both in vitro crotoxin anticoagulant activity and the in vivo lethality of whole venom (ED 50 ) was 0.94 (p value < 0.05). In conclusion, slowness in spontaneous thrombin/fibrin generation even after recalcification elicit time lapse sufficient for elaboration of one dose-response curve to pro- or anti-coagulant agonists in CPS. We propose this methodology as an alternative and sensitive assay for assessing antivenom neutralizing ability in plasma of immunized horses as well as for in-process quality control., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Phospholipases A2 (PLA2) are enzymes acting on the cell membrane phospholipids resulting in fatty acids and lysophospholipids and deconstructing the cell membrane. This protein is commonly found in snake venoms, causing tissue inflammation in the affected area. Evidence indicates that snakes have natural resistance to their own venom due to protective properties in plasma, that inhibit the action of proteins present in their venom. Given that, this study aimed to purify and characterize a γPLI from Bothrops jararaca serum, named γBjPLI. PLA2 inhibitor was isolated using two chromatographic steps: an ion exchange column (DEAE), followed by an affinity column (crotoxin coupled to a CNBr-activated Sepharose resin). The purity and biochemical characterization of the isolated protein were analyzed by RP-HPLC, SEC, SDS-PAGE, circular dichroism and mass spectrometry. The ability to inhibit PLA2 was determined by enzymatic activity, neutralization of paw edema and myonecrosis. The protein purity was confirmed by RP-HPLC and SEC, whilst an apparent molecular mass of 25 kDa and 20 kDa was obtained by SDS-PAGE, under reducing and non-reducing conditions, respectively. According to mass spectrometry analysis, this protein showed 72% and 68% of coverage when aligned to amino acid sequences of two proteins already described as PLIs. Thus, the inhibitory activity of enzymatic, edema and myonecrotic activities by γBjPLI suggests a role of this inhibitor for protection of these snakes against self-envenomation.

Snake venom is a variable phenotypic trait, whose plasticity and evolution are critical for effective antivenom production. A significant reduction of the number of snake donations to Butantan Institute (São Paulo, Brazil) occurred in recent years, and this fact may impair the production of the Brazilian Bothropic Reference Venom (BBRV). Nevertheless, in the last decades a high number of Bothrops jararaca specimens have been raised in captivity in the Laboratory of Herpetology of Butantan Institute. Considering these facts, we compared the biochemical and biological profiles of B. jararaca venom from captive specimens and BBRV in order to understand the potential effects of snake captivity upon the venom composition. Electrophoretic analysis and proteomic profiling revealed few differences in venom protein bands and some differentially abundant toxins. Comparison of enzymatic activities showed minor differences between the two venoms. Similar cross-reactivity recognition pattern of both venoms by the antibothropic antivenom produced by Butantan Institute was observed. Lethality and neutralization of lethality for B. jararaca venom from captive specimens and BBRV showed similar values. Considering these results we suggest that the inclusion of B. jararaca venom from captive specimens in the composition of BBRV would not interfere with the quality of this reference venom., Biological Significance: Snakebite envenomation is a neglected tropical pathology whose treatment is based on the use of specific antivenoms. Bothrops jararaca is responsible for the majority of snakebites in South and Southeastern Brazil. Its venom shows individual, sexual, and ontogenetic variability, however, the effect of animal captivity upon venom composition is unknown. Considering the reduced number of wild-caught snakes donated to Butantan Institute in the last decades, and the increased life expectancy of the snakes raised in captivity in the Laboratory of Herpetology, this work focused on the comparative profiling of B. jararaca venom from captive snakes and the Brazilian Bothropic Reference Venom (BBRV). BBRV is composed of venom obtained upon the first milking of wild-caught B. jararaca specimens, and used to assess the potency of all bothropic antivenoms produced by Brazilian suppliers. The use of proteomic strategies, added to biochemical and neutralization tests, allowed to conclude that, despite some subtle differences detected between these two venoms, venom from captive specimens could be used in the BBRV composition without affecting its quality in antivenom potency assays., (Copyright © 2017. Published by Elsevier B.V.)

Considering that the scarcity of venom represents a huge challenge for biochemical and functional studies of Micrurus species (coral snakes), in this report we describe for the first time the influence of pilocarpine administration prior to venom milking on the yield and protein composition of Micrurus corallinus venom. The administration of pilocarpine resulted in an increase of about 127% in the volume of venom milked, with similar protein content. Venoms showed similar protein bands distribution and intensity by SDS-PAGE and equivalents RP-HPLC profiles. Our proteomic analysis showed that venoms milked in the presence and absence of pilocarpine presented comparable protein profiles, in terms of protein composition and relative abundance. The toxins identified were assigned to 13 protein families and represent the most complete M. corallinus venom proteome described so far, in terms of number of protein families identified. Our data indicate that the administration of pilocarpine prior to venom milking increases the venom yield and does not change significantly the venom composition of M. corallinus. The employment of pilocarpine represents a useful approach to increase the yield of venom not only for Micrurus species, but also for other genera of snakes with limitations regarding the amount of venom available., Significance: In this report, we evaluated the influence of pilocarpine administration prior to venom milking in the overall composition of M. corallinus venom. We showed that the use of pilocarpine 10min before M. corallinus venom milking increases venom yield by ~127%. Not only the volume of venom obtained is higher, but also the protein concentration of both venoms is similar, opposing the idea that a more diluted venom is obtained as a result of pilocarpine administration, observed in non-front-fanged snakes. Shotgun proteomics analysis revealed that venom milked with and without the use of this drug showed similar overall protein composition and relative abundances. In addition, our proteomic approach allowed the identification of 13 toxin families in M. corallinus venom, representing the most complete M. corallinus venom proteome described so far. Moreover, two of these toxin families were identified for the first time in the venom of this species. Thus, considering the scarcity of Micrurus venom for biochemical and functional studies, we highlighted the usefulness of pilocarpine administration prior to venom milking to increase the venom yield of these snakes., (Copyright © 2017 Elsevier B.V. All rights reserved.)

The number of snakes donated to the Brazilian Instituto Butantan has been decreasing in the past 10 years. This circumstance motivated us to compare the properties of five venom pools of Bothrops jararaca snake stored for up to 54 years. Results showed differences among venom pools regarding enzymatic and other biological activities, such as caseinolytic, phospholipase A 2 , hemorrhagic and coagulant activities, as well as antigenicity. Protein content, reverse-phase chromatographic profile, and immunorecognition by commercial Bothrops antivenom were comparable for all venom pools, although lethality of the most recent preparations was higher. Since the lowest functional activities did not always correspond to older venoms, differences among venom pools used for antivenom production during the period 1963-2008 may correlate with the different proportions of venoms from different localities used in their generation, rather than to long-term storage. We conclude that B. jararaca venoms properly stored for long periods of time retain their structural and pharmacological activities, thus representing useful materials for scientific research and antivenom production., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Background: Snakes belonging to the Bothrops genus are vastly distributed in Central and South America and are responsible for most cases of reported snake bites in Latin America. The clinical manifestations of the envenomation caused by this genus are due to three major activities-proteolytic, hemorrhagic and coagulant-mediated by metalloproteinases, serine proteinases, phospholipases A 2 and other toxic compounds present in snake venom. Interestingly, it was observed that snakes are resistant to the toxic effects of its own and other snake's venoms. This natural immunity may occur due the absence of toxin target or the presence of molecules in the snake plasma able to neutralize such toxins., Methods: In order to identify anti-venom molecules, we construct a cDNA library from the liver of B. jararaca snakes. Moreover, we analyzed the expression profile of four molecules-the already known anti-hemorrhagic factor Bj46a, one gamma-phospholipase A 2 inhibitor, one inter-alpha inhibitor and one C1 plasma protease inhibitor-in the liver of juvenile and adult snakes by qPCR., Results: The results revealed a 30-fold increase of gamma-phospholipase A 2 inhibitor and a minor increase of the inter-alpha inhibitor (5-fold) and of the C1 inhibitor (3-fold) in adults. However, the Bj46a factor seems to be equally transcribed in adults and juveniles., Discussion: The results suggest the up-regulation of different inhibitors observed in the adult snakes might be a physiological adaptation to the recurrent contact with their own and even other snake's venoms throughout its lifespan. This is the first comparative analysis of ontogenetic variation of expression profiles of plasmatic proteins with potential anti-venom activities of the venomous snake B. jararaca . Furthermore, the present data contributes to the understanding of the natural resistance described in these snakes., Competing Interests: The authors declare there are no competing interests.

Bothrops jararaca is a slender and semi-arboreal medically relevant pit viper species endemic to tropical and subtropical forests in southern Brazil, Paraguay, and northern Argentina (Misiones). Within its geographic range, it is often abundant and is an important cause of snakebite. Although no subspecies are currently recognized, geographic analyses have revealed the existence of two well-supported B. jararaca clades that diverged during the Pliocene ~3.8Mya and currently display a southeastern (SE) and a southern (S) Atlantic rainforest (Mata Atlântica) distribution. The spectrum, geographic variability, and ontogenetic changes of the venom proteomes of snakes from these two B. jararaca phylogroups were investigated applying a combined venom gland transcriptomic and venomic analysis. Comparisons of the venom proteomes and transcriptomes of B. jararaca from the SE and S geographic regions revealed notable interpopulational variability that may be due to the different levels of population-specific transcriptional regulation, including, in the case of the southern population, a marked ontogenetic venom compositional change involving the upregulation of the myotoxic PLA2 homolog, bothropstoxin-I. This population-specific marker can be used to estimate the proportion of venom from the southern population present in the B. jararaca venom pool used for the Brazilian soro antibotrópico (SAB) antivenom production. On the other hand, the southeastern population-specific D49-PLA2 molecules, BinTX-I and BinTX-II, lend support to the notion that the mainland ancestor of Bothrops insularis was originated within the same population that gave rise to the current SE B. jararaca phylogroup, and that this insular species endemic to Queimada Grande Island (Brazil) expresses a pedomorphic venom phenotype. Mirroring their compositional divergence, the two geographic B. jararaca venom pools showed distinct bioactivity profiles. However, the SAB antivenom manufactured in Vital Brazil Institute neutralized the lethal effect of both venoms to a similar extent. In addition, immobilized SAB antivenom immunocaptured most of the venom components of the venoms of both B. jararaca populations, but did not show immunoreactivity against vasoactive peptides. The Costa Rican bothropic-crotalic-lachesic (BCL) antivenom showed the same lack of reactivity against vasoactive peptides but, in addition, was less efficient immunocapturing PI- and PIII-SVMPs from the SE venom, and bothropstoxin-I, a CRISP molecule, and a D49-PLA2 from the venom of the southern B. jararaca phylogroup. The remarkable paraspecificity exhibited by the Brazilian and the Costa Rican antivenoms indicates large immunoreactive epitope conservation across the natural history of Bothrops, a genus that has its roots in the middle Miocene. This article is part of a Special Issue entitled: Omics Evolutionary Ecolog., (Copyright © 2015 Elsevier B.V. All rights reserved.)

Antithrombin inhibits blood coagulation through the interaction with serine proteases in both intrinsic and extrinsic pathways. In addition, antithrombin also shows anti-inflammatory properties, which are independent of its effects on coagulation. This work shows for the first time the cloning and sequencing of antithrombin from a snake species. This predicted protein is composed by 430 amino acids and presents about 64.5% sequence identity to human antithrombin. Biacore experiments revealed that the binding affinity of Bothrops jararaca snake antithrombin to heparin was ~30 times higher than that of human antithrombin. Furthermore, Bothrops jararaca antithrombin is more effective in preventing acute inflammation induced by carrageenan when compared to human antithrombin. Hence, the results showed herein suggest that Bothrops jararaca antithrombin can play a key role in the control of acute inflammation and that this molecule might be used as a pharmacological tool and as a prototype for drug development.

Objective and Design: Antithrombin is known as the most important natural coagulation inhibitor and has been shown to have anti-inflammatory properties. The present study aimed to investigate the effects of Bothrops jararaca antithrombin on acute inflammation induced by carrageenan in mice., Methods: We evaluated the anti-inflammatory activity of antithrombin on models of paw edema formation, cell migration and leukocyte-endothelium interaction in mice (Swiss; n = 5). Acute inflammation was induced by the administration of carrageenan (15 mg kg⁻¹)., Results: Treatment with B. jararaca antithrombin (1 mg kg⁻¹) 1 h before or after carrageenan administration significantly inhibited paw edema formation, reduced cell influx to the peritoneal cavity due to reduction in the migration of polymorphonuclear cells, and attenuated leukocyte rolling in the microcirculation of the cremaster muscle.The effects of antithrombin on vascular and cellular events of inflammation were completely abolished by treatment with the cyclo-oxygenase inhibitor indomethacin (4 mg kg⁻¹), suggesting the involvement of prostacyclin in the mechanism of inflammation inhibition by B. jararaca antithrombin., Conclusion: This work showed for the first time the anti-inflammatory properties of B. jararaca antithrombin on vascular and cellular events of inflammation. These findings suggest that antithrombin is effective in preventing paw edema formation, cell migration and leukocyte rolling induced by carrageenan in mice.

Chagas disease, or American trypanosomiasis, is a parasitic disease caused by the protozoan Trypanosoma cruzi and is transmitted by insects from the Triatominae subfamily. To identify components involved in the protozoan-vector relationship, we constructed and analyzed cDNA libraries from RNA isolated from the midguts of uninfected and T. cruzi-infected Triatoma infestans, which are major vectors of Chagas disease. We generated approximately 440 high-quality Expressed Sequence Tags (ESTs) from each T. infestans midgut cDNA library. The sequences were grouped in 380 clusters, representing an average length of 664.78 base pairs (bp). Many clusters were not classified functionally, representing unknown transcripts. Several transcripts involved in different processes (e.g., detoxification) showed differential expression in response to T. cruzi infection. Lysozyme, cathepsin D, a nitrophorin-like protein and a putative 14 kDa protein were significantly upregulated upon infection, whereas thioredoxin reductase was downregulated. In addition, we identified several transcripts related to metabolic processes or immunity with unchanged expressions, including infestin, lipocalins and defensins. We also detected ESTs encoding juvenile hormone binding protein (JHBP), which seems to be involved in insect development and could be a target in control strategies for the vector. This work demonstrates differential gene expression upon T. cruzi infection in the midgut of T. infestans. These data expand the current knowledge regarding vector-parasite interactions for Chagas disease.

The ontogenetic variability in venom composition of some snake genera, including Bothrops, as well as the biological implications of such variability and the search of new molecules that can neutralize the toxic components of these venoms have been the subject of many studies. Thus, considering the resistance of Bothrops jararaca to the toxic action of its own venom and the ontogenetic variability in venom composition described in this species, a comparative study of the plasma composition of juvenile and adult B. jararaca snakes was performed through a proteomic approach based on 2D electrophoresis and mass spectrometry, which allowed the identification of proteins that might be present at different levels during ontogenetic development. Among the proteins identified by mass spectrometry, antihemorrhagic factor Bj46a was found only in adult plasma. Moreover, two spots identified as phospholipase A2 inhibitors were significantly increased in juvenile plasma, which can be related to the higher catalytic PLA2 activity shown by juvenile venom in comparison to that of adult snakes. This work shows the ontogenetic variability of B. jararaca plasma, and that these changes can be related to the ontogenetic variability described in its venom.

Rhipicephalus (Boophilus) microplus is an ectoparasite responsible for an important decrease in meat, milk and leather production, caused both by cattle blood loss and by the transmission of anaplasmosis and babesiosis. R. microplus is a rich source of serine protease inhibitors, including the trypsin inhibitors BmTI-A and BmTI-6, the subtilisin inhibitor BmSI, and the recently described thrombin inhibitor, boophilin. Boophilin is a double Kunitz-type thrombin inhibitor, with the unusual ability to form a ternary complex with a second (non-thrombin) serine proteinase molecule. The large-scale expression and purification of boophilin and of its isolated N-terminal (D1) domain in Pichia pastoris, its expression profile, and the effect of RNAi-mediated gene silencing in tick egg production are reported. Full-length boophilin and D1 were expressed at 21 and 37.5mg/L of culture, respectively. Purified boophilin inhibited trypsin (K(i) 0.65 nM), neutrophil elastase (K(i) 21 nM) and bovine thrombin (K(i) 57 pM), while D1 inhibited trypsin and neutrophil elastase (K(i) of 2.0 and 129 nM, respectively), but not thrombin. Boophilin gene silencing using RNAi resulted in 20% reduction in egg weight production, suggesting that the expression of boophilin in this life stage would be important but not vital, probably due to functional overlap with other serine proteinase inhibitors in the midgut of R. microplus. Considering our data, Boophilin could be combining with other antigen in a vaccine production for tick control., (Copyright © 2012 Elsevier B.V. All rights reserved.)

Blood coagulation is an important process in haemostasis, and disorders of blood coagulation can lead to an increased risk of haemorrhage and thrombosis. Coagulation is highly conserved in mammals and has been comprehensively studied in humans in the investigation of bleeding or thrombotic diseases. Some substances can act as inhibitors of blood coagulation and may affect one or multiple enzymes throughout the process. A specific thrombin inhibitor called infestin has been isolated from the midgut of the haematophagous insect Triatoma infestans. Infestin is a member of the nonclassical Kazal-type serine protease inhibitors and is composed of four domains, all of which have a short central α-helix and a small antiparallel β-sheet. Domains 1 and 4 of infestin (infestins 1 and 4) possess specific inhibitory activities. Infestin 1 inhibits thrombin, while infestin 4 is an inhibitor of factor XIIa, plasmin and factor Xa. Here, the structure determination and structural analysis of infestin 1 complexed with trypsin and of infestin 4 alone are reported. Through molecular modelling and docking, it is suggested that the protein-protein binding site is conserved in the infestin 1-thrombin complex compared with other Kazal-type inhibitors. Infestin 4 is able to bind factor XIIa, and the F9N and N11R mutants selected by phage display were shown to be more selective for factor XIIa in comparison to the wild type.

The proteomic analysis of plasma samples represents a challenge as a result of the presence of highly abundant proteins such as albumin. To enable the detection of biomarkers, which are commonly low-abundance proteins, in complex blood fluids, it is necessary to remove high-abundance proteins efficiently. Moreover, there is a range of about 10 orders of magnitude for the abundance of different protein species in serum. Here, we describe for the first time a study of reptilian albumin depletion using resins usually used in mammalian plasma depletion procedures. We performed the depletion of albumin from Bothrops jaraca plasma using the HiTrap Blue high-performance column (GE Healthcare Life Sciences, Piscataway, NJ, USA) and the kit Albumin & IgG Depletion SpinTrap column (GE Healthcare Life Sciences). In addition, proteomic approaches were used to analyze reptilian plasma. Our results showed that B. jararaca albumin bound to both columns, but those interactions were not enough to remove a large amount of albumin to reach an enrichment of low-abundance proteins. Although the depletion techniques used in this work were not the best to remove B. jararaca plasma albumin, our present work highlights the similarity between B. jararaca and mammalian albumin, contributing to the knowledge of comparative hemostatic proteins.

Saliva of blood-sucking arthropods contains a complex mixture of anti-haemostatic, anti-inflammatory and immune-modulator compounds. Among anti-haemostatic factors, there are anticoagulants, vasodilators and platelet aggregation inhibitors. Previous analyses of the sialotranscriptome of Aedes aegypti showed the potential presence of a Kazal-type serine protease inhibitor in the female salivary glands, carcass and also in the whole male, which inhibitor we named AaTI (A. aegypti thrombin inhibitor). Recently, we expressed and characterized rAaTI as a trypsin inhibitor, and its anticoagulant activity [1]. In this work we characterized the thrombin inhibition mechanism of rAaTI. Recombinant AaTI was able to prolong prothrombin time, activated partial thromboplastin time and thrombin time. In contrast, AaTIΔ (rAaTI truncated form) and C-terminal AaTI acidic tail prolong only thrombin time. In the competition assay, rAaTI, AaTIΔ or C-terminal AaTI acidic tail-thrombin interactions seem to be affected by heparin but not by hirudin, suggesting that rAaTI binds to thrombin exosite 2. Finally, the thrombin inhibition assay of rAaTI showed an uncompetitive inhibition mechanism. In conclusion, rAaTI can probably inhibit thrombin by interacting with thrombin exosite 2, and the interaction is not mediated by the AaTI C-terminal region, since the truncated AaTIΔ form also prolongs thrombin time., (Copyright © 2010 Elsevier Masson SAS. All rights reserved.)

Coagulation factor VIII (FVIII) concentrates are used in the treatment of patients with Hemophilia A. Human FVIII was purified directly from plasma using anion exchange chromatography followed by gel filtration. Three Q-Sepharose resins were tested, resulting in 40% recovery of FVIII activity using Q-Sepharose XL resin, about 80% using Q-Sepharose Fast Flow and 70% using the Q-Sepharose Big Beads. The vitamin K-dependent coagulation factors co-eluted with FVIII from the anion exchange columns. In the second step of purification, when Sepharose 6FF was used, 70% of FVIII activity was recovered free from vitamin K-dependent factors.

Kazal-type inhibitors play several important roles in invertebrates, such as anticoagulant, vasodilator and antimicrobial activities. Putative Kazal-type inhibitors were described in several insect transcriptomes. In this paper we characterized for the first time a Kazal unique domain trypsin inhibitor from the Aedes aegypti mosquito. Previously, analyses of sialotranscriptome of A. aegypti showed the potential presence of a Kazal-type serine protease inhibitor, in female salivary glands, carcass and also in whole male, which we named AaTI (A. aegypti trypsin inhibitor). AaTI sequence showed amino acid sequence similarity with insect thrombin inhibitors, serine protease inhibitor from Litopenaeus vannamei hemocytes and tryptase inhibitor from leech Hirudo medicinalis (LDTI). In this work we expressed, purified and characterized the recombinant AaTI (rAaTI). Molecular weight of purified rAaTI was 7 kDa rAaTI presented dissociation constant (K(i)) of 0.15 and 3.8 nM toward trypsin and plasmin, respectively, and it weakly inhibited thrombin amidolytic activity. The rAaTI was also able to prolong prothrombin time, activated partial thromboplastin time and thrombin time. AaTI transcription was confirmed in A. aegypti female salivary gland and gut 3 h and 24 h after blood feeding, suggesting that this molecule can act as anticoagulant during the feeding and digestive processes. Its transcription in larvae and pupae suggested that AaTI may also play other functions during the mosquito's development., (Copyright 2010 Elsevier Masson SAS. All rights reserved.)

Venous and arterial thromboembolic diseases are still the most frequent causes of death and disability in high-income countries. Clinical anticoagulants are inhibitors of enzymes involved in the coagulation pathway, such as thrombin and factor X(a). Thrombin is a key enzyme of blood coagulation system, activating the platelets, converting the fibrinogen to the fibrin net, and amplifying its self-generation by the activation of factors V, VIII, and XI. Thrombin has long been a target for the development of oral anticoagulants. Furthermore, selective inhibitors of thrombin represent a new class of antithrombotic agents. For these reasons, a number of specific thrombin inhibitors are under evaluation for possible use as antithrombotic drugs. This paper summarizes old and new interests of specific thrombin inhibitors described in different animals.