Biodegradation of polyether algal toxins–Isolation of potential marine bacteria

Abstract

Marine algal toxins such as brevetoxins, okadaic acid, yessotoxin, and ciguatoxin are polyether compounds. The fate of polyether toxins in the aqueous phase, particularly bacterial biotransformation of the toxins, is poorly understood. An inexpensive and easily available polyether structural analog salinomycin was used for enrichment and isolation of potential polyether toxin degrading aquatic marine bacteria from Florida bay area, and from red tide endemic sites in the South Florida Gulf coast. Bacterial growth on salinomycin was observed in most of the enrichment cultures from both regions with colony forming units ranging from 0 to 6 × 107 per mL. The salinomycin biodegradation efficiency of bacterial isolates determined using LC-MS ranged from 22% to 94%. Selected bacterial isolates were grown in media with brevetoxin as the sole carbon source to screen for brevetoxin biodegradation capability using ELISA. Out of the two efficient salinomycin biodegrading isolates MB-2 and MB-4, maximum brevetoxin biodegradation efficiency of 45% was observed with MB-4, while MB-2 was unable to biodegrade brevetoxin. Based on 16S rRNA sequence similarity MB-4 was found have a match with Chromohalobacter sp.

Rapid Biotic and Abiotic Transformation of Toxins produced by Ostreopsis. cf. ovata

“…Indeed, bacteria are known to preferentially target oxygen-rich molecules over several days [53,54], explaining their affinity for highly hydroxylated molecules like OVTX and LGTX [5,8] as confirmed by the untargeted approach. These transformation rates are comparable with those of saxitoxin and neosaxitoxin obtained after 12 to 24 h (>90%, [29]), but were much quicker than those obtained for gonyautoxin [29], PbTx-2 [30] or microcystin-LR [31]. Other studies on PbTx-2 suggest a rapid (<24 h) microbial breakdown that is mediated by microalgae and not bacteria [55,56].…”

“…The extraction efficiency achieved with the two other polymeric sorbents HLB and StrataX was not significantly lower than for the SDBL sorbent; however, these two phases did not provide good reproducibility and had a longer processing time. Despite similar functional groups, the StrataX and the HLB sorbents did not display the same behavior; this difference might be attributed to the differences in their particle sizes (28)(29)(30)(31)(32)(33)(34) µm in StrataX against 50-65 µm in HLB).…”

“…Most studies have focused on the uptake of small soluble compounds easily assimilated by bacteria, such as amino-acids, sugars, glucose, osmolytes, vanillic acid and dimethylsulfidepropionate [24][25][26][27][28]. While phycotoxins are also a constituent of microalgal exometabolomes that could be taken up by bacteria and biotransformed [29][30][31], this process has been generally overlooked.…”

Evaluation of Rapid, Early Warning Approaches to Track Shellfish Toxins Associated with Dinophysis and Alexandrium Blooms

“…The differences seen between the toxins in cells compared to the resin may reflect a contrast between what is excreted by cells and what is retained intracellularly as Nagai et al [ 54 ] demonstrated the release of extracellular toxins in cultures of Dinophysis acuminata. Alternatively, differences could also reflect the transformation of these toxins within the water column via bacterial degradation (as seen for other toxins; [ 55 , 56 ]). While this study found that SPATT samplers were able to detect toxins in the water column 3–4 weeks earlier than shellfish detections and MacKenzie et al [ 22 ] reported SPATT DSP detection at least a week earlier than shellfish, Pizarro et al [ 28 ] found that Dinophysis cells provided a more reliable early warning of shellfish toxicity than SPATT.…”

Photochemical release of sediment bound brevetoxin (PbTx-2) from resuspended sediments

“…There is a paucity of knowledge on the fate of brevetoxins in marine waters after a bloom has subsided and K. brevis cell counts return to baseline levels. Known sinks of brevetoxins in marine water columns are biological uptake and metabolism (Redshaw et al, 2010;Shetty et al, 2010;Bricelj et al, 2012), export via aerosols (Pierce et al, 2003) sorption to sediments (Pierce et al, 2004;Hitchcock et al, 2012;Mendoza et al, 2008), and photodegradation (Kieber et al, 2010). Mendoza et al (2008) reported detectable levels of brevetoxins in surface sediments collected five months after a K. brevis bloom.…”