Gender differences in the immune system activities of sea urchin Paracentrotus lividus

In the immune system of vertebrates, gender-specific differences in individual immune competence are well known. In general, females possess more powerful immune response than males. In invertebrates, the situation is much less clear. For this purpose we have chosen to study the immune response of the two sexes of the echinoderm Paracentrotus lividus in pre- and post-spawning phases. The coelomic fluid from the echinoderms contains several coelomocyte types and molecules involved in innate immune defenses. In this article we report that the degree of immune responses in the P. lividus differs according to sex in both pre- and post-spawning phases. We found in all tests that females were more active than males. The results indicate that females possess a significant higher number of immunocytes consisting of phagocytes and uncolored spherulocytes. Since the immunological activity is mainly based on immunocytes, it was not surprising that females possessed the highest values of cytotoxicity and hemolysis activity and showed a greater ability to uptake neutral red and phagocyte yeasts cells, while the average number of ingested particles per active phagocyte was not significantly different. Furthermore, agglutinating activity was more evident in the coelomocyte lysate and coelomic fluid of females than in those of males. Finally we found that the acidic extract of female gonads possessed greater antimicrobial activity than that of male gonads. These results make it very likely that gender differences in the immune response are not restricted to vertebrates; rather, they are a general evolutionary phenomenon

Attività citotossica dei celomociti di Holothuria tubulosa (Echinodermata)

Numerosi studi hanno accertato che nel fluido celomatico degli echinodermi sono presenti cellule con attività diretta verso agenti estranei. In particolare i celomociti svolgono un repertorio di funzioni immunitarie tra cui la fagocitosi, la citotossicità, l’attività antibatterica, la formazione di capsule e il rigetto dei trapianti. Nel presente lavoro abbiamo studiato l’attività citotossica dei celomociti di Holothuria tubulosa (Oloturoideo) non separati ed abbiamo utilizzato cellule di mammifero come target. I celomociti prelevati dal fluido celomatico lisano gli eritrociti di coniglio o di montone e le cellule tumorali della linea eritromieloide umana K562. Inoltre anche il supernatante del lisato dei celomociti (CLS) ha mostrato attività litica contro gli stessi target cellulari. L’analisi del CLS attraverso un “overlay” di eritrociti di montone su un gel di polyacrilamide? in assenza di SDS, ha evidenziato la presenza di almeno due bande con attività litica e differente mobilità elettroforetica. Le bande litiche eluite ed analizzate in SDS-PAGE mostrano una taglia molecolare di 79 e 44 kDa. Questi dati preludono ad ulteriori ricerche per l’identificazione dei tipi cellulari responsabili dell’attività, per l’analisi di un più ampio spettro di target e per la caratterizzazione delle due componenti proteiche apparentemente dotate di attività litica

Preliminary results on antimicrobial activity of Rhynchophorous ferrugineus hemolymph

Rhynchophorus ferrugineus (Coleoptera: Curculionidae), known as the Red Palm Weevil (RPW) and accidentally introduced in the Mediterranean areas, is considered a quarantine pest for tree palms especially in the urban environment. In order to understand the relationship among potential pathogens and RPW several studies were carried out on RPW immune system. Here we report the results of a preliminary study undertaken to investigate the effect of naturally occurring antimicrobial activities present both in the cell free hemolymph and in hemocytes lysate supernatant of RPW. The hemolymph was extracted from the older larvae sampled from infested palm trees. The protein fractions were extracted from hemolymph and hemocyte lysate supernatant by acidic precipitation. Antimicrobial activity was tested against a group of medical, veterinary and entomo-pathogenic bacterial strains. The antimicrobial activity was evaluated by determining minimal inhibitory concentrations (MICs) against planktonic form of the isolates using a standard micro-method. Data from this research could be useful to help for screening selection of entomopathogenic as well to search potential antimicrobial peptides against human or veterinary pathogens from insect sources

In vivo modulation of Bacillus thuringiensis (commercial form) on Holothuria tubulosa immune defense mechanisms

In invertebrates, cellular and humoral components are evolved to maintain their homeostais and integrity. Both these components respond to different non-self such as microorganisms, vertebrate erythrocytes and foreign proteins. The aim of this research was to study the possible modulating effects of Bacillus thuringiensis (Bt) in a commercial and vegetative form on the immune response of the echinoderm, sea cucumber Holothuria tubulosa. Bt is one of the most used biopesticides worldwide, covering the 90% of the organic market. Sicily is a region vocated to biological control and agricultural area are often closed to the coastal area. Investigate the effect of biopesticides on other non target organisms is important in a more exhaustive environmental risk assessment. Moreover correlative studies indicate that the immune surveillance is affected by both Bt forms in vivo challenge. In particularly we have evaluated the phagocitosys vs Saccharomyces cerevisiae, hemagglutination using rabbit erythrocytes and coelomocyte cytotoxic activity against rabbit erythrocytes and K562 tumor target cells. These results can contribute to improve the knowledge about the use of Bt like biological insecticidal on non target organisms

Separated hemocyte populations from the ascidian Ciona intestinalis contain and release in vitro opsonizing Ca2+-independent and β-galactoside specific lectins

Cytosolic lectins, Ca2+-independent and β-galactoside-specific, were determined to be containedin hemocyte and pharynx lysate supernatants of Ciona intestinalis, as revealed by hemagglutinationassay with trypsinized rabbit erythrocytes. Ca2+-independence and decreasing β-galactosidesinhibitory capacity (TDG > LacNAc ≥ Lactose > Galactose) have been considered properties typical ofgalectins. These lectins can be promptly released by hemocytes maintained in vitro suggesting theirinvolvement in defense responses including inflammatory reactions. Both cell lysate supernatants andhemocyte culture medium presented β-galactoside-inhibitable opsonizing activity versus yeast.Although a Percoll density gradient separation method showed that several hemocyte types containand release β-galactoside-specific molecules, results suggest that hyaline and granular amoebocytesare the primary source of these molecules