Some cultivation-based data shows that stranded sargassum appear to harbor large numbers of Vibrio bacteria. (Image credit: Brian Lapointe, FAU Harbor Branch)
A new study reveals how the interplay between
Sargassum spp., marine plastic debris and Vibrio Bacteria create the perfect “pathogen” storm, impacting both marine life and public health. vibrio Bacteria are found in bodies of water around the world and are the Leading cause of human death from the marine environment. For example, Vibrio vulnificus, sometimes referred to as the flesh-eating bacterium, can cause life-threatening foodborne illnesses through eating seafood, as well as illness and death through open wound infections.
Since 2011, sargassum, free-living populations of brown macroalgae, were fast eexpand in the Sargasso Sea and other parts of the open ocean such as the Great Atlantic sargassum belt, including frequent and unprecedented accumulations of seaweed on beaches. Marine plastic debris, first found in surface waters of the Sargasso Sea, has become a global problem and is known to persist for decades longer than natural substrates in the marine environment.
Little is currently known about the ecological relationship of vibrios sargassum. In addition, there was a lack of genomic and metagenomic evidence on whether vibrios colonize marine plastic debris and sargassum could potentially infect humans. With summer in full swing, efforts are being made to find innovative solutions for repurposing Sargassum, could these substrates pose a triple public health hazard?
Florida Atlantic University researchers and collaborators have completely sequenced the genomes of 16 vibrio Varieties derived from eel larvae, plastic waste in the sea, sargassumand seawater samples from the Caribbean and Sargasso Seas in the North Atlantic. What they discovered is Vibrio pathogens have a unique ability to “stick” to microplastics, and these microbes may be adapting to plastic.
“Plastic is a new element that was introduced to the marine environment and has only been around for about 50 years,” said Tracy Mincer, Ph.D., corresponding lead author and assistant professor of biology at FAU’s Harbor Branch Oceanographic Institute, and Harriet L. Wilkes Honors College. “Our laboratory work has shown that these vibrio are extremely aggressive and can find and stick to plastic within minutes. We also found that there are binding factors that microbes use to attach to plastics, and it’s the same mechanism that pathogens use.”
The study published in the journal
shows that open-ocean vibrios represent a previously undescribed group of microbes, some of which represent potential new species and possess a mix of pathogenic and low nutrient uptake genes that reflect their pelagic habitat and the substrates and hosts they colonize . This study uses the metagenome assembled genome (MAG) and is the first vibrio sp. Genome assembled from plastic waste.
The study highlighted vertebrate pathogen genes that are closely related to cholera and non-cholera bacterial strains. Phenotype testing of the cultivars confirmed rapid biofilm formation as well as hemolytic and lipophospholytic activities, consistent with pathogenic potential.
Researchers also discovered that zonula occludens toxin or “Zot” genes were being described for the first time Vibrio cholerae, a secreted toxin that increases gut permeability, were among the best conserved and selected genes in the vibrios they found. These vibrios appear to enter through the gut, get stuck in the gut, and infect there.
“Another interesting thing we discovered is a set of genes called ‘Zot’ genes that cause leaky gut syndrome,” Mincer said. “For example, when a fish eats a piece of plastic and becomes infected with it vibriowhich then leads to a leaky gut and diarrhea, releasing waste nutrients like nitrogen and phosphate that could be stimulants sargassum growth and other surrounding organisms.”
The results show some vibrio sp. In this environment, they have an “omnivorous” lifestyle, targeting both plant and animal hosts, combined with the ability to survive in oligotrophic conditions. With increasing humanSargassum – Plastic marine litter Through interactions, the associated microbial flora of these substrates could harbor potent opportunistic pathogens. Importantly, some cultivation-based data shows that they are stranded sargassum seem to contain large amounts of it vibrio Bacteria.
“I don’t think, at this point in time, anyone has really given any thought to these microbes and their ability to cause infection,” Mincer said. “We are keen to raise public awareness of these associated risks. Caution is required, especially during harvesting and processing sargassum biomass until the risks are more thoroughly assessed.”
Co-authors of the study are the NIOZ Royal Netherlands Institute for Sea Research, the Japan Agency for Marine-Earth Science and Technology, the Ludwig-Maximilians-Universität Munich, Germany, Emory University, the University of Amsterdam and the Marine Biological Laboratory.
This research was supported by the National Science Foundation (NSF) (Grant OCE-1155671 awarded to Mincer), FAU World Class Faculty and Scholar Program (Grant awarded to Mincer), NSF (Grant OCE-1155571 awarded to Linda A. Amaral-Zettler) , Ph.D., Corresponding Author, NIOZ), NSF (Grant OCE-1155379 awarded to Erik R. Zettler, Ph.D., Co-Author, NIOZ), NSF TUES Grant (Grant DUE-1043468 awarded to Linda Zettler and Eric Zettler).