Culturable associated-bacteria of the sponge Theonella swinhoei show tolerance to high arsenic concentrations

Abstract

Sponges are potent filter feeders and as such are exposed to high fluxes of toxic trace elements, which can accumulate in their body over time. Such is the case of the Red Sea sponge Theonella swinhoei, which has been shown to accumulate up to 8500 mg/Kg of the highly toxicelement arsenic. T. swinhoei is known to harbor a multitude of sponge-associated bacteria, so it is hypothesized that the associated-bacteria will be tolerant to high arsenic concentration. This study also investigates the fate of the arsenic accumulated in the sponge to test if the associated-bacteria have an important role in the arsenic accumulation process of their host, since bacteria are key players in the natural arsenic cycle. Separation of the sponge to sponge cells and bacteria enriched fractions showed that arsenic is accumulated by the bacteria. Sponge-associated, arsenic-tolerant bacteria were cultured in the presence of 5 mM of either arsenate or arsenite (equivalent to 6150 mg/Kg arsenic, dry weight). The 54 isolated bacteria were grouped to 15 operational taxonomic units (OTUs) and isolates belonging to 12 OTUs were assessed for tolerance to arsenate at increased concentrations up to 100 mM. Eight of the 12 OTUs tolerated an order of magnitude increase in the concentration of arsenate, and some exhibited external biomineralization of arsenic–magnesium salts. The biomineralization of this unique mineral was directly observed in bacteria for the first time. These results may provide an explanation for the ability of the sponge to accumulate considerable amounts of arsenic. Furthermore arsenic-mineralizing bacteria can potentially be used for the study of bioremediation, as arsenic toxicity affects millions of people worldwide.

Insights into the lifestyle of uncultured bacterial natural product factories associated with marine sponges

“…Related Candidatus Entotheonella bacteria were also detected in the sponge Discodermia dissoluta (8), the source of the anticancer drug candidate discodermolide (9,10), but their chemical role remains unclear (11). Despite repeated efforts (12,13), the vast majority of T. swinhoei symbionts, including Ca. Entotheonella, remain uncultured to date, except for a report on the detection of Ca.…”

The multi-omics promise in context: from sequence to microbial isolate

“…Thus, antibiotics and their production and resistance loci detectable in multi-omics data can be used as selection criteria for the isolation of target organisms. This may include the prevention of overgrowth by fast-growing microorganisms (Sizova et al 2012;Hames-Kocabas & Uzel 2012;Rettedal et al 2014;Keren et al 2015) or selection for specific phenotypic traits such as those characteristic for Gram-positive bacteria or production of antibiotic-resistant spores.…”

A novel Chromatiales bacterium is a potential sulfide oxidizer in multiple orders of marine sponges

“…S2). Previous studies have isolated anaerobic sulfate reducing Desulfovibrio from T. swinhoei (Lavy et al, 2014;Keren et al, 2015;. A co-localization of sulfate reducing and sulfide oxidizing bacteria was recently found in the sponge G. barretti (Jensen et al, 2016).…”