Percorrer por autor "Karaveti, Emmanouela"
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- Assessing the impact of gram-negative bacteria on the common octopus, in relation to rising sea temperature: a study of total protein concentration and hemolysis activity in hemolymphPublication . White, Daniella-Mari; Karaveti, Emmanouela; Bakopoulos, VasileiosFish farming may pose a risk to adjacent octopus farms due to pathogen transmission. Moreover, the immune defense mechanisms of cephalopods are still not fully understood. This study aimed to determine changes in total protein concentration and hemolysis activity of Octopus vulgaris hemolymph, after intramuscular (IM) or intravenous (IV) challenges with aquaculture fish pathogens (either Photobacterium damselae subsp. piscicida or damselae or Vibrio alginolyticus or anguillarum O1) at two temperatures (21 ± 0.5 ℃ and 24 ± 0.5 ℃). Results showed that Octopus vulgaris exhibited a mean total protein concentration of 173.93 ± 69.37 mg/mL across all experimental conditions, markedly exceeding values reported for other mollusks, such as the bivalves Chamelea gallina (0.75–1.66 mg/mL) and Mytilus galloprovincialis (0.59–1.60 mg/mL). Patterns of total protein concentration, related to the genera of the pathogen used for the challenges, were observed. Four-way ANOVA revealed significant main effects of bacterium (F(3, 144) = 54.360, p < 0.001) and temperature (F(1, 144) = 10.014, p = 0.002) on total protein, along with multiple significant interaction effects, including bacterium × temperature, route × time, and bacterium × route × temperature × time (all p < 0.001). Hemolysis remained at low levels across both experimental temperatures, challenge routes, and pathogens, not exceeding 25 % in any case. Values above 15 % and up to 20 % were recorded in specific conditions, such as Photobacterium damselae subsp. damselae at 24 ± 0.5 ◦C on Day 3 in CIM-, IM-, and IV- control and challenged groups respectivelly; V. alginolyticus at 24 ± 0.5 ◦C on Day 3 in IM-challenged groups; and Vibrio anguillarum O1 at 21 ± 0.5 ◦C on Day 3 and Day 7 in IM-challenged groups. ANOVA for hemolytic activity showed significant main effects of bacterium (F(3, 144) = 22.032, p < 0.001) and temperature (F(1, 144) = 4.083, p = 0.045), with multiple significant interactions, including bacterium × temperature, route × time, and bacterium × route × temperature × time (all p < 0.001). These results indicate that the route of challenge may play a major role in hemolysis activity, with temperature and time post-challenge also exerting significant effects, possibly through a complex synergistic interaction. Our results may assist in elucidating common octopus defense mechanisms against common fish pathogens and provide important information to the scientific community and the marine aquaculture sector.
- Evaluation of the effect of season and raft location on the immune status and byssus production of mussels cultivated in Galicia (Rías Baixas)Publication . Karaveti, Emmanouela; Costa Portela, María del Mar; Silva, Rui Cabral eClimate change presents a serious threat to marine ecosystems, impacting both wild and cultivated species. One of the most important cultivated species in Europe is the Mediterranean mussel, Mytilus galloprovincialis, which is primarily produced along the nutrient-rich Galician coastline in northwest Spain. This mussel species is crucial for the local economy and provides many jobs in the region. Due to their filter-feeding lifestyle, mussels constantly face environmental stress and depend on their innate immune system, primarily mediated by hemocytes, to survive. In this study, we investigated how ocean waves and seasonal changes affect the immune system of cultivated mussels and how these factors influence byssus production, the structure that helps mussels attach to surfaces. To evaluate the immune response, we measured oxidative activity-free radicals such as reactive oxygen species (ROS) and nitric oxide (NO). Besides, the gene expression of glutathione S-transferase (GST), lysozyme (LYS), and heat shock protein 70 (HSP70) was assessed. Our results showed that immune responses varied significantly with the seasons, peaking in the summer, likely due to higher temperatures and consequently the potential proliferation of pathogenic organisms, and increased metabolic demands. We also examined byssus production through the expression of the mussel foot protein Mgfp3 gene. Our findings indicated that the expression of the Mgfp3 varied seasonally, being probably affected by factors such as hydrodynamic forces and temperature, peaking in spring. Overall, this study highlights the complex relationship between climate factors and mussel performance. It emphasizes the importance of implementing sustainable aquaculture practices that consider seasonal variations and climate impacts. Understanding these dynamics is crucial for adapting mussel farming strategies to the challenges posed by climate change, ensuring the resilience of this vital species.