Dipartimento di Biologia, Ecologia e Scienze della Terra

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Arm growth and regeneration in octopus (Octopus vulgaris and Eledone moschata)
(Università della Calabria, 2020-02-12) Baldascino, Elena; Cerra, Maria Carmela; Fiorito, Graziano
Here I evaluated the timing and rate of arm regeneration in octopus, a cephalopod mollusc, and contributed to the understanding of the molecular machinery involved in arm growth and regeneration in two octopus’ species: Octopus vulgaris and Eledone moschata. This work stands and revisit in part the first experimental study on arm regeneration in cephalopod molluscs, including the two species carried out by M. Lange (1920). An arm of octopus may fully regenerate and regrowth in few months after amputation. Lange recognized three stages: wound healing, tissue degeneration and tissue renewal. I applied the 3Rs principle to this study utilizing samples and data from a previous study, thus limiting the number or live animals humanely killed for the purpose of this PhD project. During the analysis of data, I found the same three stages in O. vulgaris arm regeneration to occur. I was not able to observe similar series of events in E. moschata, probably due to limited time and conditions of the animals. I found that O. vulgaris increased significantly body weight in 21 weeks. The growth appeared to be affected by repeated anesthesia, thus encouraging further studies on the physiological responses to stress in octopus. Data I analyzed confirm the view that O. vulgaris is characterized by rapid non-asymptotic growth, with high individual variability. Octopuses elongate their arms continuing to grow over time with no significant difference in the relative rate of elongation between anterior and posterior arms. The arms that underwent to regeneration, appear to have a faster growth when compared with the contralateral arms (but repeated anesthesia influenced the rate of growth of regenerating arms). Data analyzed extent the study of Lange, by providing morphometric information on the relative growth rate of the arms (regenerating vs contralateral), for the first time. A significant change in the relative expression profile of the tip vs the proximal part of the arm in O. vulgaris was observed using different approaches, confirming and extending the view that the tip the arm represents an exceptional biological system where continuous growth is achieved through massive cellular differentiation and interesting molecular events. I identified 39 genes in O. vulgaris and seven in E. moschata and studied their involvement in arm growth and/or regeneration events in octopus arms. These studies are novel.
Learning and memory in Octopus vulgaris: search of the underlying biological machinery
(Università della Calabria, 2021-03-01) Manzo, Paolo; Cerra, Maria Carmela; Fiorito, Graziano
The cephalopod mollusc Octopus vulgaris is known for the richness of behavioral repertoire, neural and behavioral plasticity, and complex cognition rivaling higher Vertebrates. Animals are known to learn over a variety of tasks, equipped with different sensory-motor systems, i.e. visual and tactile, and able to recall the outcomes of their experience for long term (e.g., ‘one month’ Sutherland, 1957; ‘some months’ Sanders, 1970). In the present study, a fear conditioning training protocol was adopted to evaluate O. vulgaris behavioral responses to an artificial stimulus to be avoided. Behavioral outcomes have been tested for the effect of a protein synthesis inhibitor on memory acquisition and retention, and for changes in the pattern of expression of genes potentially involved in memory formation. Applying the 3Rs principle, I used samples from a previous study, thus limiting the number or live animals humanely killed for the aims of this PhD project. My experiments and analysis allowed to: i. Identify that cycloheximide-induced protein synthesis inhibition did not alter the octopus ability to acquire an avoidance learning task. However, octopuses ability to retain and recall the memory was impaired; ii. Data available to me did not allow to rule out a state-dependent effect of cycloheximide injection that somehow affects memory recall and octopuses ability to learn; iii. Identify 24 target genes, nine memory-related genes and 15 epigenetic modifiers, from O. vulgaris transcriptome, and studied their gene expression profile in relation with learning and memory consolidation.
Arm growth and regeneration in octopus (Octopus vulgaris and Eledone moschata)
(Università della Calabria, 2020-02-07) Baldascino, Elena; Cerra, Carmela; Fiorito, Graziano

Dipartimento di Biologia, Ecologia e Scienze della Terra - Tesi di dottorato

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