Study of defensive behavior of a venomous snake as a new approach to understand snakebite.

Snakebites affect millions of people worldwide. The majority of research and management about snakebites focus on venom and antivenom, with less attention given to snake ecology. The fundamental factor in snakebites is the snakes' defensive biting behavior. Herein we examine the effects of environmental variables (temperature, time of day, and human stimulus) and biological variables (sex and body size) on the biting behavior of a medically significant pit viper species in Brazil, Bothrops jararaca (Viperidae), and associate it with the epidemiology of snakebites. Through experimental simulations of encounters between humans and snakes, we obtained behavioral models applicable to epidemiological situations in the State of São Paulo, Brazil. We found a significant overlap between behavioral, morphological, environmental, and epidemiological data. Variables that increase snakebites in epidemiological data also enhance the tendency of snakes to bite defensively, resulting in snakebites. We propose that snakebite incidents are influenced by environmental and morphological factors, affecting the behavior of snakes and the proportion of incidents. Thus, investigating behavior of snakes related to snakebite incidents is a valuable tool for a better understanding of the epidemiology of these events, helping the prediction and, thus, prevention of snakebites.

Male genital system of Ameiva ameiva (Squamata: Teiidae).

Understanding squamate reproductive morphology is crucial for investigating ecological, behavioral, and evolutionary questions. Here, we describe the anatomy and histology of the male genital system of Ameiva ameiva from southeastern Brazil. Ten adult males were dissected to characterize genital macroscopy and collect fragments of the testes, gonadoducts, and kidneys for histological examination. We examined 10 transverse histological sections per individual and measured the epithelial height of the epididymis and ductus deferens. The male reproductive system consists of a pair of yellowish oval testes, the rete testis, ductuli efferentes, epididymis, ductus deferens, ampulla ductus deferentis, sexual segment of the kidney (SSK), cloaca, and hemipenis. The hemipenis is elongated, cylindrical, and unilobed, with a sulcate face and an asulcate face, which has continuous fringes throughout its length. Seminiferous tubules exhibited germ cells at various stages. The epididymis is wider and more coiled than the ductus deferens. The rete testis has a simple squamous epithelium with long stereocilia, while the narrower ductuli efferentes are lined by a simple ciliated cuboidal epithelium. The epididymal epithelium is pseudostratified columnar, with basal and ciliated principal cells, whereas the ductus deferens epithelium is pseudostratified to simple cuboidal. The epididymal epithelium is 1.5 times taller than the ductus deferens epithelium. Here, we observed the SSK present in the cortex of the ventral region of the kidneys due to the hypertrophy of the distal convoluted tubules, as well as its secretory activity. Our findings will contribute to future research into the evolution of squamate reproductive morphology.

Reproductive cycles of two island pitvipers species (Serpentes, Viperidae) determined by ultrasonography and radiography.

We used ultrasonography and radiography to assess the sexual organs and characterize the reproductive cycle of captive golden lancehead (Bothrops insularis) and Alcatrazes lancehead (B. alcatraz), two endangered island snake species in Brazil. We assessed 46- individuals of golden lancehead and 12 of Alcatrazes lancehead kept in captivity between 2014 and 2020. Follicular development was similar between species, but follicles in Alcatrazes lancehead were smaller than in the golden lanceheads. Female golden lanceheads produced 24 live young, seven stillborn and 73 undeveloped eggs. Parturition of live young occurred between midsummer (February) and early autumn and gestation averaged 8 months. Female Alcatrazes lanceheads produced four live young in midsummer, and one undeveloped egg in early autumn. Males and females of both species have seasonal and biennial reproductive cycles. Sperm storage in both sexes is essential to coordinate male and female cycles. The data obtained with golden lancehead and Alcatrazes lancehead in captivity, demonstrate a degree of conservatism, following data from other Bothrops.

Reproductive maturity and sexual dimorphism of a population of Amerotyphlops brongersmianus from a Restinga area in southeastern Brazil (Serpentes: Typhlopidae).

Natural history data are important for a better understanding of distinct aspects of snake biology, and this information in scarce on Scolecophidia. Here we focus on sexual maturity and sexual dimorphism within a population of Amerotyphlops brongersmianus from the Restinga de Jurubatiba National Park, Rio de Janeiro state, Brazil. The smallest sexually active male and female showed snout-vent length of 117.5 and 158.4 mm, respectively. Females had statistically significant larger body and head length sizes, whereas males had longer tails. Juveniles showed no sexual dimorphism for any analyzed feature. Secondary vitellogenic follicles had a more opaque, yellowish/darker aspect, being larger than 3.5 mm. We reinforce that in addition to traditional features for determining sexual maturity, morphological and histological characteristics of kidneys should be evaluated in males, as well as the morphology of the infundibulum in females. Histological data show development of seminiferous tubules and presence of spermatozoa in males, and infundibulum receptacles and uterine glands in females as a sign of sexual maturity. This type of information is essential for a more accurate description of data on sexual maturity, allowing access to information on the development of reproductive structures that are not available macroscopically.

Ultrasonographic and radiographic evaluation of gestation in golden lanceheads (Bothrops insularis) in ex situ breeding programs.

The golden lancehead (Bothrops insularis) is a critically endangered snake endemic to Queimada Grande Island, southeastern Brazil. Captive breeding programs are vital for the conservation of this species. This study evaluates the gestation of two females golden lanceheads using radiography and ultrasonography. The first female was collected on the island while reproductively active (late vitellogenesis or early pregnancy) and kept in captivity. This female gave birth to five neonates after an 8-month gestation period, which is longer than estimates based on specimens preserved in museums. The second female copulated in captivity in July and probably ovulated in October. In this case, no embryonic development was detected, and the female deposited 14 undeveloped eggs approximately 6 months after ovulation.

Morphological and structural differences between the hemipenes and hemiclitores of golden lancehead snakes, Bothrops insularis (Amaral, 1922), revealed by radiography.

The golden lancehead (Bothrops insularis) is a critically endangered and island endemic snake. A remarkable characteristic of golden lanceheads is the high frequency of females showing hemiclitores. Here, we use radiography to identify morphological and structural differences between the hemipenes and hemiclitores in captive individuals. Sex was identified using the probing method and confirmed by visualizing the gonads by ultrasound. Hemipenes appeared as herringbone-shaped structures with bone radiopacity and hemiclitores as triangular structures with soft tissue radiopacity. These differences suggest that hemiclitores spines fail to develop the level of ossification observed in hemipenis spines.

Reproductive cycles of neotropical boid snakes evaluated by ultrasound.

Snakes have increasingly been bred as pets around the world. Few studies have addressed the reproduction of boid snakes, and no study has addressed their reproductive cycles in captivity. Thus, this paper describes the reproductive aspects of Brazilian boids in captivity. We used ultrasonography to characterize the reproductive cycle of four boid species in captivity in the Southern Hemisphere: the anaconda (Eunectes murinus), the red-tailed boa (Boa constrictor constrictor), the Amazon tree boa (Corallus hortulanus), and the rainbow boa (Epicrates cenchria). Nonvitellogenic follicles occurred from January to December in anaconda and red-tailed boa and for a shorter period from September to February in Amazon tree boa and from January to May in rainbow boa. Vitellogenesis occurred from late June to late March in E. murinus in year-round (12 months), from March to March in Amazon tree boa, from late September to late March in red-tailed boa, and from late March to late September in rainbow boa. Mating occurred from late March to late September in red-tailed boa and rainbow boa and from late September to late March in Amazon tree boa. No mating was observed in anacondas, but a female probably underwent parthenogenesis. Births occurred in July in anaconda and in March to July in Amazon tree boa and from December to March in red-tailed boa and rainbow boa. In males, increases in testicular size were associated with the mating season. Ultrasonography proved to be a safe and noninvasive technique to study the reproductive cycle of giant snakes in captivity.

Morphology and seasonality of the sexual segment of the kidney in genus Bothrops snakes.

In Squamata, the sexual segment of the male kidney (SSK) produces secretory granules that are transmitted to the female tract during copulation. Here, we investigate the morphology of SSK in various species of the pitviper-genus Bothrops, a medically relevant clade of Neotropical snakes, using histology, histochemistry, as well as scanning and transmission electron microscopy. We also evaluated the relationship of SSK hypertrophy with spermatogenesis and storage of sperm. The SSK in Bothrops consists of tall columnar epithelial cells filled with electron-dense secretory granules. These granules are apparently released into the lumen by an apocrine secretory process. In general, the ultrastructural morphology of SSK in Bothrops is similar to those described for other pitvipers in the genus Agkistrodon. In most Bothrops males, the SSK produces carbohydrates and proteins, and occurs in all lobes of the kidney, occupying most of the kidney mass. In contrast, intersexual females (with male copulatory organs) of Bothrops insularis had a smaller SSK diameter than males and did not show hypertrophy. The seasonal development of SSK in Bothrops species seems to be driven by environmental factors rather than phylogeny, since sister species exhibited periods of hypertrophy at different months. In most Bothrops males, hypertrophy occurs at various seasons of the year (spring, summer, autumn), even in winter, and seasonal changes in SSK do not necessarily accompany spermatogenesis.

Short-term cold storage of seminal samples of the golden lancehead pitviper (Bothrops insularis).

Assisted reproductive technologies such as cooling, freezing, and artificial insemination are essential in conserving genetic diversity of critically endangered reptiles like the golden lancehead pitviper (Bothrops insularis). Therefore, we examined viability of semen samples from captive golden lanceheads diluted in coconut-water based extender over a 48-h period of cooling (5°C). Semen evaluations were performed immediately after the dilution and at 6, 24, and 48 h, using computer-assisted sperm analysis and stains to assess plasma membrane and acrosomal status. Our findings showed that the extender and protocol employed here were effective in preserving golden lancehead pitviper spermatozoa for a short periods of time (48 h), allowing semen samples to be transported to distant locations for immediate use without the setbacks of cryopreservation.

Evidence of facultative parthenogenesis in three Neotropical pitviper species of the Bothrops atrox group.

We examined four suspected cases of facultative parthenogenesis in three species of a neotropical lineage of pitvipers of the Bothrops atrox group. Reproduction without mating was observed in captive females of B. atrox, B. moojeni and B. leucurus housed alone for seven years (the two former species) and nine years (the latter one). In addition to the observation of captivity data, we investigated molecularly this phenomenon using heterologous microsatellites. DNA was extracted from the mothers' scales or liver, from embryo and newborn fragments, and yolked ova. Four of the microsatellites showed good amplification using Polymerase Chain Reaction and informative band segregation patterns among each mother and respective offspring. Captivity information, litter characteristics (comparison of the number of newborns, embryos and yolked ova) and molecular data altogether agreed with facultative parthenogenesis predictions in at least three out of the four mothers studied: B. atrox (ID#933) was heterozygous for three out of the four markers, and the sons S1 and S2 were homozygous; B. moojeni (BUT86) was heterozygous for two out of four markers, offspring S1, S3, E2, and E4, and O1 to O6 were homozygous; and B. leucurus (MJJS503) was heterozygous for three out of four markers, and son E1 and O1 were homozygous. B. moojeni (BUT44) was homozygous for all loci analyzed in the mother and offspring, which although not informative is also consistent with parthenogenesis. This study represents the first molecular confirmation of different pitviper species undergoing facultative parthenogenesis among Neotropical endemic snakes.

Enterococcus faecalis causes osteitis deformans in aGolden Lancehead snake (Bothrops insularis): a case report / Enterococcus faecalis causa osteíte deformante em uma serpente Jararaca-ilhoa (Bothrops insularis): relato de caso

Osteitis deformans (Paget's disease) is a chronic bone disorder characterized by excessive osteoclast-mediated bone resorption followed by new bone formation. The present paper reports this condition in an 18-year-old captive golden lancehead (Bothrops insularis) from Brazil. This patient initially exhibited anorexia and swelling in the middle third of the spine associated with locomotor disability. For diagnosis, radiography, ultrasound, computed tomography, cytology, and microbiological culture were performed. Diagnostic imaging showed bone changes, vertebral fusion, and bone proliferation. Cytology revealed blood cells how toxic heterophiles, reactive monocytes, young red blood cells, and polychromasia compatible with an infectious process. A bacterial culture identified an ampicillin-susceptible strain of Enterococcus faecalis. Antibiotic treatment was promptly started, but the snake died 25 days later. Histopathologically, the bone tissue showed a generalized thickening of the vertebral trabeculae. For the first time, the presence of E. faecalisassociated with the development of osteitis deformans in snakes was presented.(AU)

Osteíte deformante (Doença de Paget) é um distúrbio ósseo crônico caracterizado por reabsorção óssea excessiva mediada por osteoclastos, seguida por nova formação óssea. O presente trabalho relata essa condição em uma serpente jararaca-ilhoa (Bothrops insularis) do Brasil de 18 anos. O paciente apresentou inicialmente anorexia e um inchaço no primeiro terço médio da coluna associado com a incapacidade locomotora. O diagnóstico foi estabelecido com o apoio de radiografia, ultrassonografia, tomografia computadorizada, citologia e cultura microbiológica. O diagnóstico por imagem mostrou alterações ósseas, fusão de vértebras e proliferação óssea. A citologia mostrou células sanguíneas como heterófílos tóxicos, monócitos reativos, células sanguíneas jovens e policromasia compatíveis com um processo infeccioso. A cultura bacteriana identificou uma cepa de Enterococcus faecalis suscetível à ampicilina. O tratamento com antibióticos foi iniciado imediatamente, mas a serpente morreu 25 dias depois. Histopatologicamente, o tecido ósseo mostrou um espessamento generalizado das trabéculas vertebrais. Portanto, foi demonstrado pela primeira vez a presença de E. faecalis associada ao desenvolvimento de osteíte deformante em uma serpente.(AU)

How Does Oocyte Uptake Occur? A Macroscopic Study of the Ovarian and Oviductal Modifications for Egg Capture in the Coral-Snake Micrurus corallinus.

The processes of follicular development, ovulation, egg capture, and egg transport vary among vertebrates. Therefore, analysis of the reproductive tract of several lineages is needed for understanding the evolutionary changes of the reproductive system. In turtles, the ovulated eggs are released into the coelomic cavity and taken up by one of the two oviducts, a phenomenon called extrauterine migration of eggs. However, the process of egg uptake in lizards is different. The egg is ovulated directly into the infundibulum, and oocyte uptake by the contralateral oviduct rarely occurs. The same pattern has been hypothesized to occur in snakes. To test this hypothesis, we analyzed the reproductive tract of female Micrurus corallinus preserved in zoological collections. We examined the anatomical characteristics of the infundibulum and ovary and compared the reproductive output between the ovaries to verify the mechanism of egg capture and the anatomical viability of extrauterine migration of eggs. The reproductive output of the right ovary was higher than that of the left ovary, and the higher number of eggs in the right oviduct is due exclusively to the production of the ipsilateral ovary. Several anatomical features prevent extrauterine migration of eggs, including the asymmetry of the reproductive system, the arrangement of the ovarian follicles in a single row, and the formation of a wrapping around the ovary and infundibulum by the visceral pleuroperitoneum membrane (preventing against ectopic eggs). Therefore, the hypothesis of egg capture by the contralateral oviduct is anatomically infeasible in M. corallinus and possibly in other snakes. Anat Rec, 301:1936-1943, 2018. © 2018 Wiley Periodicals, Inc.

Hundred legs good, two fangs better: adult centipede (Scolopendridae) devoured by a juvenile Amazon lancehead, Bothrops atrox (Viperidae) / Uma centena de pernas é eficaz, mas duas presas são ainda melhores: lacraia adulta (Scolopendridae) devorada por uma jovem serpente amazônica, Bothrops atrox (Viperidae)

Centipedes are part of the diet of several snake species of the genus Bothrops. However, reports on predation of centipedes by snakes are normally incomplete, and important data for natural history studies as the species identification and size of the prey are rarely published. The aim of this work was to report the presence of the centipede Scolopendra viridicornis in the digestive tract of the Amazon pit viper B. atrox. The snake specimen is an immature female from Aripuanã, state of Mato Grosso, Brazil, having a 623 mm snout-vent length. The centipede is an adult Scolopendra viridicornis, estimated to be 190 mm long, and found in the snake's stomach. The success in preying on this large and potentially dangerous centipede could be explained by the snake's dimensions, large enough for overpowering the prey, but still retaining characteristics of youth, such as venom with specific action against specific prey items.

Lacraias fazem parte da dieta de diversas espécies de serpentes do gênero Bothrops. Entretanto, informações importantes para estudos de história natural, como identificação da espécie e tamanho de presas, são raramente publicados. O objetivo desse trabalho é registrar a presença de uma lacraia Scolopendra viridicornis, no trato digestivo de uma jararaca da Amazônia, Bothrops atrox. A serpente estudada é uma fêmea imatura, com 623 mm de comprimento rostro-cloacal, proveniente de Aripuanã, estado de Mato Grosso, Brasil. A lacraia é um adulto de Scolopendra viridicornis parcialmente digerida, com aproximadamente 190 mm de comprimento. O sucesso na predação dessa grande e perigosa presa pode ser explicado pelas dimensões da serpente, que é grande o suficiente para dominar a presa, mas ainda retém características juvenis, como veneno com ação específica em determinados ítens alimentares.

The South-American rattlesnake Crotalus durissus: feeding ecology in the central region of Brazil / La serpiente cascabel sudamericana Crotalus durissus: ecología alimentar en la región central de Brasil

Abstract We investigated food patterns in the diet composition of 452 specimens of Crotalus durissus from Central Brazil. Thirty-three items were recorded corresponding to four categories: rodents (75.76%), marsupials (6.06%), unidentified mammals (9.09%) and reptiles (9.09%). Adults of both sexes and some juveniles feed mostly on mammals, specifically rodents, it is the most active and abundant prey throughout the year mainly in areas from Cerrado. In addition, we observed that in C. durissus there is a trend in the diet of females could be more diverse, maybe this can be associated to sexual differences involving different strategies of the feeding biology of this rattlesnake.

Resumen Patrones de alimentación fueron investigados en la composición de la dieta de 452 ejemplares de Crotalus durissus de Brasil central. Treinta y tres ítems fueron registrados, correspondientes a cuatro categorías: roedores (75.76%), marsupiales (6.6%), mamíferos no identificados (9.09%) y reptiles (9.09%). Los adultos de ambos sexos e individuos jóvenes se alimentaron básicamente de mamíferos, en específico de roedores, esta es la presa más activa y abundante durante todo el año, principalmente en las áreas de Cerrado. Además fue observado que en C. durissus existe una tendencia a que la dieta de las hembras sea más diversa, factor que podría estar relacionado a las diferencias sexuales que implican diferentes estrategias de alimentación en la biología de esta serpiente cascabel.

Composição, riqueza e abundância de anuros em um remanescente de Cerrado e Mata Atlântica no estado de São Paulo / Composition, species richness and abundance of anurans in a Cerrado and Atlantic Forest remnant of the São Paulo state, Brazil

Apesar da fauna de anuros no estado de São Paulo ser considerada a mais conhecida no país, ainda existem consideráveis lacunas amostrais no estado, sobretudo em remanescentes de vegetação natural das bacias hidrográficas do rio Paranapanema. Neste contexto, o objetivo deste estudo foi gerar informações sobre a composição, riqueza e abundância de anuros na Estação Ecológica de Angatuba, um remanescente de Cerrado e Mata Atlântica presente na bacia hidrográfica do Alto Paranapanema. O levantamento das espécies foi realizado em duas etapas de campo: março e novembro de 2007 e outubro de 2008 a março de 2009, totalizando 38 dias de inventário. A amostragem foi realizada por meio de armadilhas de interceptação e queda, encontro ocasional, procura auditiva e procura visual. Foram registradas 31 espécies de anuros pertencentes a 16 gêneros e oito famílias (Bufonidae, Centrolenidae, Craugastoridae, Cycloramphidae, Hylidae, Leiuperidae, Leptodactylidae e Microhylidae). Deste total, 15 espécies representam novos registros para os municípios de Angatuba e Guareí, SP. Este estudo é uma importante contribuição para ampliar o conhecimento sobre a diversidade de anuros no Cerrado e Mata Atlântica, os dois hotspots mundiais prioritários para a conservação biológica existentes no país.

The anurans of São Paulo state are the best known in the country. However, there are still considerable sampling gaps in the state, especially within natural vegetation remnants of the hydrographic basins of the Paranapanema river. The purpose of this study was to obtain information on species composition, species richness and abundance of anurans recorded at Estação Ecológica de Angatuba, a remnant of Cerrado and Atlantic Forest in the hydrographic basin of the Upper Paranapanema river. The survey was conducted in two phases: in March and November 2007, and between October 2008 and March 2009, totaling 38 sampling days. Surveys were conducted using pitfall traps, incidental encounters and acoustic and visual searches. We recorded 31 anuran species, belonging to 16 genera and eight families (Bufonidae, Centrolenidae, Craugastoridae, Cycloramphidae, Hylidae, Leiuperidae, Leptodactylidae and Microhylidae). Of this total, 15 species were new records to the Angatuba and Guareí municipalities. This research is an important contribution for expanding the knowledge of the anuran diversity in the Cerrado and Atlantic Forest, two priority global hotspots for biodiversity conservation in Brazil.

Herpetofauna de um remanescente de cerrado no estado de São Paulo, sudeste do Brasil / Herpetofauna in a cerrado remnant in the state of São Paulo, Southeastern Brazil

Apesar da grande extensão e biodiversidade, ainda existem lacunas amostrais no Cerrado. Este domínio fitogeográfico vem sofrendo modificações acentuadas devido à sua conversão em pastagens e monoculturas. Nas últimas quatro décadas ocorreu uma redução de 88,5 por cento das áreas de Cerrado no estado de São Paulo. Restam menos de 0,8 por cento da área original do Cerrado paulista, que originalmente cobria 14 por cento da área do estado. Este estudo apresenta a composição de espécies, abundância e uso de hábitat dos anfíbios e répteis que ocorrem na Estação Ecológica de Assis, um remanescente de Cerrado no estado de São Paulo. O inventário foi realizado entre setembro de 2007 e março de 2008, em sete etapas de campo mensais de cinco dias cada, totalizando 35 dias de trabalho de campo. A amostragem foi realizada por meio de armadilhas de interceptação e queda (AIQ), encontros ocasionais (EO), procura auditiva (PA) e procura visual (PV). Além da amostragem em campo, foram incluídos na lista de espécies os registros obtidos para o município de Assis presentes nas principais coleções científicas de anfíbios e répteis do estado de São Paulo. Foram registradas 27 espécies de anfíbios pertencentes a 13 gêneros e seis famílias (Bufonidae, Cycloramphidae, Hylidae, Leiuperidae, Leptodactylidae e Microhylidae) e 53 espécies de répteis pertencentes a 38 gêneros e 13 famílias (Amphisbaenidae, Anguidae, Gekkonidae, Gymnophthalmidae, Polychrotidae, Scincidae, Teiidae, Anomalepididae, Boidae, Colubridae, Dipsadidae, Elapidae e Viperidae). Este estudo é uma importante contribuição para o conhecimento destas taxocenoses no ameaçado Cerrado paulista. Nesse sentido, remanescentes como a Estação Ecológica de Assis são de extrema importância não só para a conservação da herpetofauna no estado de São Paulo, mas também para o domínio do Cerrado.

Despite its great extension and biodiversity, there are still sampling gaps in the Cerrado. This region has shown drastic changes due to the conversion of natural areas into pastures and plantations. In the last four decades, around 88.5 percent of the Cerrado areas in the state of São Paulo were supressed. Only 0.8 percent of Cerrado original cover in the state (14 percent) remain as pristine habitats. We present the species composition, abundance and use of habitat of amphibians and reptiles recorded at Estação Ecológica de Assis, a remnant of Cerrado in the state of São Paulo. The survey was conducted between September 2007 and March 2008 during seven monthly field trips of five days each, totaling 35 sampling days. Surveys were conducted using pitfall traps (AIQ), incidental encounters (EO), auditory encounters (PA), and visual encounters (PV). In addition to the field samples, we included records of species occurring on the municipality of Assis, obtained at the main scientific collections of amphibians and reptiles in the state of São Paulo. We recorded 27 amphibian species, belonging to 13 genera and six families (Bufonidae, Cycloramphidae, Hylidae, Leiuperidae, Leptodactylidae, and Microhylidae), and 53 reptile species belonging to 38 genera and 13 families (Amphisbaenidae, Anguidae, Gekkonidae, Gymnophthalmidae, Polychrotidae, Scincidae, Teiidae, Anomalepididae, Boidae, Colubridae, Dipsadidae, Elapidae, and Viperidae). This survey is an important contribution to the knowledge about these assemblages in the highly threatened Cerrado of the state of São Paulo. Remnants such as the Estação Ecológica de Assis are extremely important for the conservation of amphibians and reptiles in the state and in the Cerrado region.

Peptidase activities in the semen from the ductus deferens and uterus of the neotropical rattlesnake Crotalus durissus terrificus.

To understand the role of peptidases in seminal physiology of Crotalus durissus terrificus, intra- and inter-seasonal activity levels of acid (APA), basic (APB), puromycin-sensitive (APN-PS) and puromycin-insensitive neutral (APN-PI), cystyl (CAP), dipeptidyl-IV (DPPIV), type-1 pyroglutamyl (PAP-I) and prolyl-imino (PIP) aminopeptidases as well as prolyl endopeptidase (POP) were evaluated in soluble (SF) and/or membrane-bound (MF) fractions of semen collected from the ductus deferens of the male reproductive tract and from the posterior portion of the uterus. Seminal APB, PIP and POP were detected in SF, while other peptidases were detected in SF and MF. Only the convoluted posterior uterus in winter and autumn had semen. Relative to other examined peptidases, in general, APN-PI, APN-PS and APB activities were predominant in the semen from the uterus and throughout the year in the semen from the ductus deferens, suggesting their great relevance in the seminal physiology of C. d. terrificus. The levels of peptidase activities in the ductus deferens semen varied seasonally and were different from those of semen in the uterus, suggesting that their modulatory actions on susceptible peptides are integrated to the male reproductive cycle events and spermatozoa viability of this snake.