From birth to adulthood: An analysis of the Brazilian lancehead (Bothrops moojeni) venom at different life stages.

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.

Ontogenetic study of Bothrops jararacussu venom composition reveals distinct profiles.

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 PLA2 K-49 and more proteases; and adults with a lot of the same myotoxic PLA2, 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.

Sexual and ontogenetic variation of Bothrops leucurus venom.

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.