Marine sponges belonging to the phylum Porifera (Metazoa), evolutionarily the oldest animals are the single best source of marine natural products. The present review presents a comprehensive overview of the source, taxonomy, country of origin or geographical position, chemical class, and biological activity of sponge-derived new natural products discovered between 2001 and 2010. The data has been analyzed with a view to gaining an outlook on the future trends and opportunities in the search for new compounds and their sources from marine sponges.

The discovery of natural products derived from marine sources has demonstrated a consistent upward trajectory for the decade of 2011-2020, holding significant promise for the development of novel drugs and many other marine bioproducts. In recent years, the spotlight has shifted away from marine sponges (Porifera) towards marine microorganisms as the primary source of discovery. Despite reports of marine sponges spanning 20 different orders and being the subject of 769 papers between 2011 and 2020, they only contributed to 19.29% of all new compounds discovered, in contrast to 51.94% by marine microorganisms and phytoplankton. 563 new compounds were reported from marine sponge-associated microbes, more than doubling the number for the previous decade (2001-2010). It heralds a positive outlook for a sustainable resource strategy as the extraction of bioactive compounds produced by pure cultures of sponge-associated microbes could overcome supply challenges that arise with isolation from host sponges for the same compound. However, the application of novel marine natural products (MNPs) remains challenging due to the limited yield of compounds from large amounts of sponges. This review covers the literature published between 2011 and 2020, focusing on MNPs isolated from marine sponges. A total of 2603 new compounds are documented, detailing their chemical classification, biological activities, source country or geographic locations, and the taxonomic information of the source organisms, including order, family, genus, and species.

Sponge-bacteria interactions are very important due to their ecological and biological significance. To understand the impact of interactions between sponges and bacteria (both associated with and external to sponges) on sponge-associated microbial diversity, sponge metabolite profiles and bioactivity, we used a controlled aquarium system and designed an experimental approach that allows the study of sponge-bacteria interactions in a well-defined manner. To test the feasibility of this approach, this system was used to study the interaction between a spongeAplysilla roseaand a marine bacterium commonly found in seawater,Vibrio natriegens. Sponge explants were exposed toV.natriegens, at 5 × 10⁶cfu/ml, and changes were monitored for 48 hours. Pyro-sequencing revealed significant shifts in microbial communities associated with the sponges after 24 to 48 hours. Both the control (sponge only without added bacteria) andVibrio-exposed sponges showed a distinct shift in bacterial diversity and abundance with time.Vibrioexposure significantly increased bacterial diversity, the abundance of a number of taxa compared to control sponges. The result experimentally supports the notion of dynamic and concerted responses by the sponge when interacting with a bacterium, and demonstrates the feasibility of using this controlled aquarium system for the study of sponge-bacteria interactions.

Aspergillus is a ubiquitous soil-dwelling organism found in organic debris, dust, compost, foods, spices, and rotted plants. The genus Aspergillus includes over 185 species. Around 20 species have so far been reported as causative agents of opportunistic infections in humans. Among these, Aspergillus fumigatus is the most commonly isolated species, followed by Aspergillus flavus and Aspergillus niger. Aspergillus oryzae, Aspergillus terreus, Aspergillus ustus, and Aspergillus versicolor are among the other species less commonly isolated as opportunistic pathogens (Rinaldi, 1983). Aspergillus spp. are well known to play a role in three different clinical settings in humans: (1) opportunistic infections, (2) allergic states, and (3) toxicoses. Immunosuppression is the major factor predisposing to development of opportunistic infections (Ho and Yuen, 2000). Aspergillus, like other lamentous fungi, is primarily acquired from an inanimate reservoir, usually by the inhalation of airborne spores. The organism grows best at 37°C, and the small spores (2-3 µm) are easily inhaled and deposited deep in the lungs, leading to a variety of clinical syndromes (Figure 14.1). These infections may present in a wide spectrum, varying from local involvement to dissemination and as a whole called aspergillosis. Among all lamentous fungi, Aspergillus is in general the most commonly isolated one in invasive infections. It is the second most commonly recovered fungus in opportunistic mycoses following Candida. Although these are distinct pulmonary entities, on rare occasions, one condition may change to another; for example, an aspergilloma may change to invasive pulmonary aspergillosis (IPA) (Tomee et al., 1995).