Gradual specialization of phagocytic ameboid cells may have impaired regenerative capacities in metazoan lineages

When studying host-pathogen interactions, the method of administration of the pathogen is a crucial parameter to control the injected dose of bacteria and the stress experienced by the animal during manipulation. Here we developed two models of infection (balneation or injection) of Exaiptasia pallida (E. pallida) by Vibrio parahaemolyticus expressing GFP (Vp-GFP). The injection, which provided better control of the bacteria quantity introduced inside the animal, induced a stress response with contraction and rejection of bacteria. We followed Vp-GFP dissemination by confocal microscopy over time at 6, 24 and 30 hours. During the early time of infection, bacteria adhering to the ectoderm were observed in both infection methods. At the latter time of infection Vp-GFP disappeared from ectoderm and appeared in the gastroderm. In case of injection, Vp-GFP were located in the gastroderm after 6 hours, whereas in the balneation case, bacteria reached the gastroderm until 24 hours. In both methods, bacteria disappeared from the ectoderm after 6 hours. In conclusion, by using Vp-GFP, we demonstrated for the first time that we can infect E. pallida and quantified the bacteria in whole animals. We also localized them in the different tissues, especially in mesenterial filaments, which are the main entry route of bacteria independently of the infection method.

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Step-by-Step Regeneration of Tentacles after Injury in Anemonia viridis—Morphological and Structural Cell Analyses

Corte

Baranzini

Dara

et al. 2023

IJMS

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Benthic marine invertebrates, such as corals, are often subjected to injury caused by several sources. Here, the differences and characteristics in injured and health tissues in terms of cellular components are shown through a histological investigation of the soft coral Anemonia viridis at 0 h, 6 h, 24 h, and 7 days after injury caused by tentacle amputation. In addition, a new tool was used for the first time in invertebrates, positron emission tomography, in order to investigate the events that occur during regeneration within a longer time period (0 h, 24 h, and 14 days after the tentacles were cut). Higher integrated density values were measured through a densitometric analysis in sections stained with Fontana–Masson at 24 h after the tentacles were cut. This suggests an increase in melanin-like containing cells and a subsequent increase in fibroblast-like cells differentiated by amoebocytes that converge to the lesion site in the early stages of inflammation and regeneration. This work provides, for the first time, an elucidation of the events that occur during wound-healing and regeneration in basal metazoan, focusing on the characterisation of immune cells and their role. Our results indicate that Mediterranean anthozoan proves to be a valuable model for studying regeneration. Many events highlighted in this research occur in different phyla, suggesting that they are highly conserved.

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Gradual specialization of phagocytic ameboid cells may have impaired regenerative capacities in metazoan lineages

Cited by 3 publications

References 225 publications

Chitosan-based films filled with nanoencapsulated essential oil: Physical-chemical characterization and enhanced wound healing activity

Chitosan-based films filled with nanoencapsulated essential oil: Physical-chemical characterization and enhanced wound healing activity

Exploring different methods of Exaiptasia pallida infection to follow Vibrio parahaemolyticus dissemination in the whole animal

Step-by-Step Regeneration of Tentacles after Injury in Anemonia viridis—Morphological and Structural Cell Analyses

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