Physiological constraints dictate toxin spatial heterogeneity in snake venom glands

BMC Biology

Eivind A. B. Undheim¹  Brett R. Hamilton¹  Samuel D. Robinson¹  Mark C. Wilkinson²  Steven R. Hall²  Paul Rowley²  Nicholas R. Casewell²  Keirah E. Bartlett²  Taline D. Kazandjian² 

[1] Centre for Advanced Imaging, University of Queensland;Centre for Snakebite Research & Interventions, Liverpool School of Tropical Medicine;

关键词: Venom;    Snake;    Behaviour;    Adaptation;    Evolution;    Mass spectrometry imaging;   

DOI  :  10.1186/s12915-022-01350-y

来源: DOAJ

【 摘 要 】

Abstract Background Venoms are ecological innovations that have evolved numerous times, on each occasion accompanied by the co-evolution of specialised morphological and behavioural characters for venom production and delivery. The close evolutionary interdependence between these characters is exemplified by animals that control the composition of their secreted venom. This ability depends in part on the production of different toxins in different locations of the venom gland, which was recently documented in venomous snakes. Here, we test the hypothesis that the distinct spatial distributions of toxins in snake venom glands are an adaptation that enables the secretion of venoms with distinct ecological functions. Results We show that the main defensive and predatory peptide toxins are produced in distinct regions of the venom glands of the black-necked spitting cobra (Naja nigricollis), but these distributions likely reflect developmental effects. Indeed, we detected no significant differences in venom collected via defensive ‘spitting’ or predatory ‘biting’ events from the same specimens representing multiple lineages of spitting cobra. We also found the same spatial distribution of toxins in a non-spitting cobra and show that heterogeneous toxin distribution is a feature shared with a viper with primarily predatory venom. Conclusions Our findings suggest that heterogeneous distributions of toxins are not an adaptation to controlling venom composition in snakes. Instead, it likely reflects physiological constraints on toxin production by the venom glands, opening avenues for future research on the mechanisms of functional differentiation of populations of protein-secreting cells within adaptive contexts.

【 授权许可】

Unknown