Invertebrate Survival Journal

XXIII scientific meeting of the Italian Association of Developmental and Comparative Immunology (IADCI), February 13-15, 2023, DaDoM - Darwin Dohrn Museum, Villa Comunale, Naples, Italy

2023-05-08T11:58:06+00:00

First morpho-functional characterization of Anemonia viridis amoebocytes: a light microscopy study

2023-01-19T14:14:14+00:00

For the first time, we studied the morpho-functional characteristics of amoebocytes of the sea anemone Anemonia viridis. A histochemical approach was adopted and two subpopulations of amoebocytes from mesoglea were observed: granulocytes and hyalinocytes. Granulocytes showed a high number of cytoplasmatic granules, while hyalinocytes had no or few granules. Amoebocytes showed both round and spreading shapes and were divided in basophil, neutrophil or acidophil cells. Amoebocytes actively phagocytized yeast cells and produced superoxide anion. The presence of hydrolytic enzymes in amoebocytes was also investigated. Positive cells to acid phosphatase, acid esterase and non-specific esterase were found, with granulocytes and hyalinocytes that did not show different responses in term of positivity. Although preliminary, the results of this study can help to understand the features and immune role of A. viridis amoebocytes and the development of defense strategies in multicellular organisms. Moreover, this study lay the foundations for future more in-depth studies, including those at the ultrastructural level.

Pathological changes in the main immune organs of silkworm infected with Staphylococcus aureus

2023-05-31T08:55:11+00:00

Silkworm Bombyx mori (B. mori), a lepidopteran model organism, has become an important model for molecular biology. It also offers an excellent model to study the innate immunity because of its similarity to human beings. Staphylococcus aureus (S. aureus) is a typical gram-positive pathogenic microorganism that causes serious pneumonia, meningitis, endocarditis and septicemia. In this study, silkworm was used as animal model to study the innate immune responses against the pathogenic bacterial infections. We investigated the median lethal dose (LD₅₀) of S. aureus infection in the silkworm, and the pathological changes in their hemolymph and midgut after infection. The LD₅₀ of S. aureus infecting the silkworms was 4.39 × 10⁴ colony-forming units per milliliter (CFU/mL) after 72 h. The peritrophic membrane of the silkworm showed severe damage after 36 h. Insect hemocytes can participate in various innate immune responses, such as encapsulation and nodule formation. Our results imply plasmacytes of hemocytes can adhere to and spread over S. aureus in the hemolymph and may play an important role in the resistance of the silkworms to S. aureus infection.

Induction of antioxidant and detoxifying systems of Chilo suppressalis Walker after exposure to entomopathogenic fungi

2023-02-02T10:09:23+00:00

The current study aimed to determine antioxidant and detoxifying responses of Chilo suppressalis Walker (Lepidoptera: Crambidae) to Beauveria bassiana (Strains BBRR1, BBAL1, BBLN1, BBLN2), Metarhizium anisopliae and Hirsutella subulata. The interactions of insect humoral immune responses with the entered conidia of entomopathogenic fungi in addition to nodule formation and melanization caused the production of several reactive oxygenate species (ROS), such as hydrogen peroxidase (H2O2), hydroperoxides (ROOH), superoxide radicals (O2−), and hydroxyl radical (OH−). The highest activity of catalase was recorded by BBRR1 and BBAL1, treatment after 48 to 96 h while the larvae treated by BBRR1 showed the highest peroxidase activity. Both ascorbate peroxidase and glucose-6-phosphate dehydrogenase showed the highest activity in the larvae treated by BBRR1 after 48-96 h. The highest concentration of Malondialdehyde reported in the larvae treated by BBRR1, BBAL1 and BBLN1, after 48 hours. The highest activity of general esterases was recorded in the larvae treated by BBRR1 after 48-96 hours. Similar results were recorded in the activity of glutathione-S-transferase but the enzyme had also the highest activity in the larvae treated by BBAL1 and BBLN2 after 48 hours. The larvae treated by BBRR1 and BBLN1 showed the highest activity of acid phosphatase after 72 and 96 hours while the highest activity of alkaline phosphatase was obtained in the larvae only treated by BBRR1 after 48-96 hours. The results clearly revealed that BBRR1 significantly and severely induced antioxidant and detoxifying systems of C. suppressalis larvae implying on virulence and immune induction of BBRR1 against the larvae.

Cadmium exposure induced oxidative stress and histopathological disruption in the body wall of the freshwater leech Limnatis nilotica (Savigny, 1822)

2023-09-07T12:54:44+00:00

Cadmium (Cd) is considered as one of the most highly toxic heavy metal that is released into the environment on a large scale, and its concentrations in water have significantly increased as a result of human activities. In particular, contamination of rivers and drinking water may easily occur, especially in locations close to industry or mines. In this study, we examined the impact of Cd exposure on the body wall of the freshwater leech Limnatis nilotica at concentrations of 100, 200, and 300 µg/l. The findings showed that the exposure caused histopathological changes as well as oxidative stress (increased malondialdehyde concentrations (MDA)) and changes in antioxidant activity (superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (Gpx)). In fact, numerous histological changes were observed, such as cuticle deterioration, a marked increase in the number of secretory cells, increased mucus production, vacuolization of the epithelium, altered epithelial cell borders, and mucus cell hyperplasia. The histological results are consistent with the biochemical findings because we found that MDA levels significantly increased in a dose-dependent manner. Additionally, the Cd exposure disrupted the levels of the antioxidant levels. Indeed, SOD, CAT, and Gpx activities were increased in the group treated with the lower dose (100 g/l), whereas their levels dramatically decreased at higher Cd doses (200 and 300 g/l). Therefore, the presence of this heavy metal in freshwater habitats may have severe ecological risks that may lead to leech aquatic habitat destruction and fragmentation.