Relationships of biological and taxonomic characteristics to chemically mediated bioactivity in Mediterranean littoral sponges

Abstract

The aim of this study was to detect relationships of bioactive properties (antibacterial, antifungal, antiviral antimitotic and cytotoxic activities) of Mediterranean littoral sponges with some of their biological characteristics (growth habits, presence of symbiotic or epibiotic organisms, structural defences) and their systematic position. Antimitotic and cytotoxic activities were present in 80.6% and 73.6% of the species respectively, 42.2% of the species showed antibacterial activity, 29.8% were antiviral and 22.5% were antifungal. Only antiviral and antifungal activities were significantly dependent on taxonomical order, being especially important in the Axinellida. Antiviral, antifungal and antibacterial activities predominated in erect forms, and were poorly represented in encrusting forms, which, however, included a higher percentage of cytotoxic and antimitotic species. Nevertheless, only antiviral activity was significantly related to growth habit. All types of activities were significantly dependent on sponge skeletal features: the highest percentages of species with cytotoxic activity were found among horny and siliceous sponges. Also, antiviral and antibacterial activities were better represented in horny sponges. Antibacterial, antifungal and antiviral activities were dependent on the presence/absence of epibionts and seemed to be more efficient as antifouling defences than antimitotic and cytotoxic activities. Only cytotoxic activity was significantly more wide-spread in species harbouring cyanophyceae. Correspondence analysis revealed that cytotoxic and antimitotic activities were both related to encrusting forms, a siliceous skeleton, occasional epibiosis and the presence of cyanophyceae. Antifungal, antibacterial and antiviral activities were mainly related to erect or globular form, siliceous and horny skeleton and habitual (species-specific) epibiosis.