Bacteria Associated with Marine Benthic Invertebrates from Polar Environments: Unexplored Frontiers for Biodiscovery?

Abstract

The ecological function of bacteria-invertebrate interactions in Polar areas remains poorly understood, despite increasing evidence that microbial metabolites may play pivotal roles in host-associated chemical defense and in shaping the symbiotic community structure. The metabolic and physiological changes that these organisms undergo in response to adapting to extreme conditions result in the production of structurally and functionally novel biologically active molecules. Deepening our knowledge on the interactions between bacteria and their invertebrate host would be highly helpful in providing the rationale for why (e.g., competition or cooperative purpose) and which (whether secondary metabolites, enzymes, or proteins) bioactive compounds are produced. To date, cold-adapted bacteria associated with marine invertebrates from the Arctic and Antarctica have not been given the attention they deserve and the versatility of their natural products remains virtually unexplored, even if they could represent a new attractive frontier in the search for novel natural compounds. This review is aimed at showcasing the diversity of cold-adapted bacteria associated with benthic invertebrates from Polar marine areas, highlighting the yet unexplored treasure they represent for biodiscovery.

Exploring the Diversity and Metabolic Profiles of Bacterial Communities Associated With Antarctic Sponges (Terra Nova Bay, Ross Sea)

“…They have been mainly aimed at establishing the taxonomical specificity of sponge core microbiome and/or the possible vertical or horizontal transmission processes involved in the acquisition and maintenance of ancient symbionts (Taylor et al, 2007;Webster et al, 2010). However, greater efforts are available for the exploration of sponges inhabiting more accessible study areas, mainly tropical and temperate habitats, while studies performed in polar regions remain very scant (Cárdenas et al, 2014;Lo Giudice and Rizzo, 2018;Lo Giudice et al, 2019a).…”

The Variety and Inscrutability of Polar Environments as a Resource of Biotechnologically Relevant Molecules

“…Cryo-environments are particularly harmful for microbial life from both a physical (as ice crystals and rigid temperature could damage the cellular structure) and energetic point of view (as they are characterised by low rates of mass transfer of liquid water and nutrients) [3]. What in these areas should stem and limit life, i.e., wind, dryness, low temperatures and harsh salinity conditions, stimulate it insistently, by guiding its inhabitants to develop unique adaptive strategies [4].…”

“…Cold enzymes possess high catalytic efficiency at low temperature and great molecular flexibility, suitable features that make them really attracting for the industrial and biotechnological application in a sustainable and not expensive way [4]. The increased flexibility is generally due to a decreased number of hydrogen bonds and salt bridges [127,128].…”

“…The main obstacles to the concrete use of these compounds in the industrial field are their thermolability, high costs of production and processing at low temperatures [131]. Despite this, the topic remains amazing in the eyes of researchers, who currently care about energy saving attitude and prevention of undesirable chemical side reactions [4]. According to Sarmiento et al [132], the use of cold-enzymes brings numerous advantages, by reducing contamination risk and the release of chemical by-products which could occur at high temperature during the production processes in food industry.…”

Deep Hypersaline Anoxic Basins as Untapped Reservoir of Polyextremophilic Prokaryotes of Biotechnological Interest

“…Generally, marine microorganisms represent an untapped source for the discovery and development of new biomolecules due to their rich biodiversity and genetic capacity to produce unique metabolites [73][74][75]. In this regard, it is well documented that many taxonomically novel marine species are promising sources of new bioactive compounds with noteworthy pharmaceutical activities, which can become sources of novel therapeutic agents [52,76].…”