Antimicrobial peptides from echinoderms as antibiofilm agents: a natural strategy to combat bacterial infections

AbstractIncreased attention has been focused on marine invertebrates as a source of bioactive molecules for biomedical applications. Many bioactive molecules are part of the innate immune system. Some more recently isolated compounds, mainly from the sea urchin and the sea cucumber, are antimicrobial peptides (AMPs) active against Gram-positive and Gram-negative bacteria, and fungi. In this review we described the most recent studies on AMPs isolated from echinoderms. AMPs are small peptides (< 10 kDa) with cationic charge and amphipathic structure. Recently, it was demonstrated that in the coelomocyte lysates of Paracentrotus lividus and Holothuria tubulosa, AMPs possess activity against s…

Bacillus thuringiensis treatment modulate the HSP70 expression in larva and adult brain of Rhynchophorus ferrugineus

To study the pathogen-host relationship, we used the model of the entomopathogenic bacterium Bacillus thuringiensis (Bt) and Rhynchophorus ferrugineus, a quarantine pest that attacks palm trees. In particular, we focused on the Bt stress-induced infections. We studied the effect of Bt on larval and adult growth, and on the expression of the heat shock proteins (HSPs), rapidly synthesized in the cell after exposure to stress including pathogens. Bt has negative effects on larval and adult growth, on total hemocytes counts and on the hemocyte type. HSP70 was evaluated in the supernatant of the brain lysate obtained from larvae and adults fed with sublethal doses of Bt. HSP70 expression was mo…

Cytotoxic activity of Holothuria tubulosa (Echinodermata) coelomocytes.

Abstract The immune system of marine invertebrates, in particular that of holothurians, still requires further study. Our research showed that coelomocyte cells contained in the coelomic fluid of the sea cucumber, Holothuria tubulosa, are able to lyse, in vitro, red blood cells in rabbits and sheep. A plaque-forming assay showed spherule cells to be the effector cells, able to release cytotoxic molecules after xenogenic cell contact. The coelomocyte lysate supernatant, analysed by polyacrylamide gel electrophoresis overlay technique, using rabbit and sheep erythrocytes, showed two different haemolytic protein patterns: one calcium dependent and the other calcium independent. The fractions o…

Paracentrin1, a synthetic antimicrobial peptide fragment of a beta-thymosin from the sea-urchin Paracentrotus lividus, interferes whith staphylococcal and Pseudomonas aeruginosa biofilm formation

Components of hemocyte extracts from marine invertebrates exert antimicrobial activity

Morphological characterization of the blood cells in the endangered Sicilian endemic pond turtle,Emys trinacris(Testudines: Emydidae)

AbstractIn this study, measurements of morphological parameters, sizes and frequencies of peripheral blood cells (erythrocytes, leukocytes, thrombocytes) on blood smear preparation devices stained with May-Grunwald stain were evaluated for both sexes in 20 Emys trinacris (Testudines: Emydidae) specimens. Erythrocytes were higher in male than in female specimens. The leukocyte of E. trinacris contains eosinophil, basophil, monocyte, heterophil and lymphocyte. The eosinophil was higher in males than in females whereas lymphocytes were higher in females than in males. The erythrocyte morphological parameters (EL [erythrocyte length], EW [erythrocyte width], L/W [length/width], ES [erythrocyte …

Comparison among the responses of the greater wax moth, Galleria mellonella and red palm weevil Rhynchophorus ferrugineus to the entomopathogenic nematodes, Steinernema carpocapsae

The entomopathogenic nematode-bacterium complex of Steinernema-Xenorhabdus has high potential as lethal biological control agent against many insect pest species. The Red Palm Weevil (RPW) Rhynchophorus ferrugineus (Coleoptera: Curculionidae) is an important worldwide palm trees pest. This insect is a quarantined pest, accidentally introduced in Sicily in 2005. The pest is killed by Steirnenema carpocapsae, but nematodes are unable to reproduce in the RPW larvae. This research try to understand the reasons of the inability of S. carpocapsae to complete its life cycle in the host comparing what happens in one of the most suitable host, the greater wax moth, Galleria mellonella (Lepidoptera: …

The good, the bad and the ugly: Emys trinacris, Placobdella costata and Haemogregarina stepanowi in Sicily (Testudines, Annelida and Apicomplexa)

Endemic Sicilian pond turtles Emys trinacris Fritz, Fattizzo, Guicking, Tripepi, Pennisi, Lenk, Joger et Wink were examined for the presence of haemogregarine parasites. The presence of haemogregarines, occurring mainly in the microgametocyte stage (13.2 ± 0.12 μm in length and 6.4 ± 0.52 μm in width), was observed in approximately 9% of the sampled E. trinacris. Based on the observed morphology and on the sequencing of nuclear 18S rDNA, we identified the parasite as Haemogregarina stepanowi Danilewsky, 1885. Morphometric study of uninfected and infected red blood cells has shown that H. stepanowi induces different changes in erythrocyte shape depending on the infective stage. The different…

Paracentrin 1, a synthetic antimicrobial peptide fragment of a beta-thymosin from the sea-urchin Paracentrotus lividus, interferes with staphylococcal and Pseudomonas aeruginosa biofilm formation

Paracentrin 1, a synthetic antimicrobial peptide from the sea-urchin Paracentrotus lividus, interferes with staphylococcal and Pseudomonas aeruginosa biofilm formation

The rise of antibiotic-resistance as well as the reduction of investments by pharmaceutical companies in the development of new antibiotics have stimulated the investigation for alternative strategies to conventional antibiotics. Many antimicrobial peptides show a high specificity for prokaryotes and a low toxicity for eukaryotic cells and, due to their mode of action the development of resistance is considered unlikely. We recently characterized an antimicrobial peptide that was called Paracentrin 1 from the 5-kDa peptide fraction from the coelomocyte cytosol of the Paracentrotus lividus. In this study, the chemically synthesized Paracentrin 1, was tested for its antimicrobial and antibiof…

Studio su biologia, morfologia cellulare e immunità in Rhynchophorus ferrugineus (Olivier, 1970)

Does Bacillus thuringiensis Affect the Stress and Immune Responses of Rhynchophorus ferrugineus Larvae, Females, and Males in the Same Way?

Simple Summary Rhynchophorus ferrugineus is a destructive quarantine pest of palm trees, now widely distributed. Although broad-spectrum insecticides are often used to protect palm against R. ferrugineus, there is increasing concern about their effects on the environment and human health, especially where palm trees are located in urban areas. As an environmentally friendly entomopathogen, Bacillus thuringiensis (Bt) has been widely used to prevent other pest infestations. Although Bt products are the most sold bio-insecticides, there are still many interesting features to be investigated in the relationship of Bt and its hosts. We investigated the effect of Bt on larvae, females, and males…

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 mor…

Immune mediators of sea-cucumber Holothuria tubulosa (Echinodermata) as source of novel antimicrobial and anti-staphylococcal biofilm agents

The present study aims to investigate coelomocytes, immune mediators cells in the echinoderm Holothuria tubulosa, as an unusual source of antimicrobial and antibiofilm agents. The activity of the 5kDa peptide fraction of the cytosol from H. tubulosa coelomocytes (5-HCC) was tested against a reference group of Gram-negative and Gram-positive human pathogens. Minimal inhibitory concentrations (MICs) ranging from 125 to 500 mg/ml were determined against tested strains. The observed biological activity of 5-HCC could be due to two novel peptides, identified by capillary RP-HPLC/nESI-MS/MS, which present the common chemical-physical characteristics of antimicrobial peptides. Such peptides were c…

Adaptations to thermal variation in two Mediterranean limpets - cardiac response and haemocyte lysosomal stability

Patella rustica and Patella caerulea are two congeneric limpet species, both occurring along the rocky shores of the Mediterranean but on different tidal heights. P. rustica is dominant in the upper intertidal zone while P. caerulea is more abundant in the lower part of the same zone. Understanding variations in physiological adaptations to thermal stress is vital when investigating intertidal species' distribution. Hence, to investigate the relationship between their physiological thermal tolerance and intertidal zonation, laboratory experiments were designed to test the hypothesis that the lower zoned P. caerulea has reduced upper thermal limits when compared with higher zoned P. rustica,…

Discovery and SAR Evolution of Pyrazole Azabicyclo[3.2.1]octane Sulfonamides as a Novel Class of Non-Covalent N-Acylethanolamine-Hydrolyzing Acid Amidase (NAAA) Inhibitors for Oral Administration

Inhibition of intracellular N-acylethanolamine-hydrolyzing acid amidase (NAAA) activity is a promising approach to manage the inflammatory response under disabling conditions. In fact, NAAA inhibition preserves endogenous palmitoylethanolamide (PEA) from degradation, thus increasing and prolonging its anti-inflammatory and analgesic efficacy at the inflamed site. In the present work, we report the identification of a potent, systemically available, novel class of NAAA inhibitors, featuring a pyrazole azabicyclo[3.2.1]octane structural core. After an initial screening campaign, a careful structure–activity relationship study led to the discovery of endo-ethoxymethyl-pyrazinyloxy-8-azabicyclo…