" "
Satellite Banner
Technology
Networks
Scientific Communities
 
Become a Member | Sign in
Home>News>This Article
  News
Return

Extracellular Vesicles Produced by Ocean Microbes

Published: Monday, January 13, 2014
Last Updated: Sunday, January 12, 2014
Bookmark and Share
Cyanobacteria produce and release vesicles that can serve as food parcels for marine organisms.

Marine cyanobacteria - tiny ocean plants that produce oxygen and make organic carbon using sunlight and CO2 - are primary engines of Earth’s biogeochemical and nutrient cycles. They nourish other organisms through the provision of oxygen and with their own body mass, which forms the base of the ocean food chain.

Now scientists at MIT have discovered another dimension of the outsized role played by these tiny cells: The cyanobacteria continually produce and release vesicles, spherical packages containing carbon and other nutrients that can serve as food parcels for marine organisms.

The vesicles also contain DNA, likely providing a means of gene transfer within and among communities of similar bacteria, and they may even act as decoys for deflecting viruses.

In a paper published this week in Science, postdoc Steven Biller, Professor Sallie (Penny) Chisholm, and co-authors report the discovery of large numbers of extracellular vesicles associated with the two most abundant types of cyanobacteria, Prochlorococcus and Synechoccocus. The scientists found the vesicles (each about 100 nanometers in diameter) suspended in cultures of the cyanobacteria as well as in seawater samples taken from both the nutrient-rich coastal waters of New England and the nutrient-sparse waters of the Sargasso Sea.

Although extracellular vesicles were discovered in 1967 and have been studied in human-related bacteria, this is the first evidence of their existence in the ocean.

“The finding that vesicles are so abundant in the oceans really expands the context in which we need to understand these structures,” says Biller, first author on the Science paper. “Vesicles are a previously unrecognized and unexplored component of the dissolved organic carbon in marine ecosystems, and they could prove to be an important vehicle for genetic and biogeochemical exchange in the oceans.”

Billions and billions of vesicles
Biller’s metagenomic analysis of the vesicles taken from the seawater revealed DNA from a diverse array of bacteria, suggesting that vesicle production is common to many marine microbes. The researchers estimate the global production of vesicles by Prochlorococcus alone at a billion billion billion per day - representing a notable addition of carbon to the scarce nutrient pool of the open seas.

Lab experiments showed that the vesicles are stable, lasting two weeks or more, and that the organic carbon they contain provides enough nutrients to support the growth of nonphotosynthetic bacteria.

Given the dearth of nutrients in the open ocean, the daily release by an organism of a packet one-sixth the size of its own body is puzzling, Chisholm says. Prochlorococcus has lost the ability to neutralize certain chemicals and depends on nonphotosynthetic bacteria to break down chemicals that would otherwise act as toxins. It’s possible the vesicle “snack packets” help make this relationship mutually beneficial.

“Prochlorococcus is the smallest genome that can make organic carbon from sunlight and carbon dioxide and it’s packaging this carbon and releasing it into the seawater around it,” says Chisholm, the Lee and Geraldine Martin Professor of Environmental Studies in MIT’s Department of Civil and Environmental Engineering and Department of Biology, who is lead investigator of the study. “There must be an evolutionary advantage to doing this. Our challenge is to figure out what it is.”

Because the vesicles also contain DNA and RNA, the researchers surmise they could play a role in horizontal gene transfer, a means for developing genetic diversity and sharing ecologically useful genes among the Prochlorococcus metapopulation.

Marine decoy
But perhaps the most unusual potential role of the vesicles is as a decoy for predators: Electron microscopy shows phages (viruses that attack bacteria) attached to vesicles. When a phage injects its DNA into the vesicle (making it impossible for the phage to reproduce in a living cell), it renders the phage inactive, according to Biller, who says the vesicles could be acting like chaff released by a fighter jet to divert missile attacks. A phage attached to a vesicle is effectively taken out of the battle, providing a creative means of deterrence.

“Marine cyanobacteria of the genera Prochlorococcus and Synechoccocus are the two most abundant phototrophs,” says biologist David Scanlan, a professor at the University of Warwick who was not involved in this research. “By releasing extracellular vesicles these organisms shed new light on the importance of such particles in the largest ecosystem on Earth - the open ocean - with implications for marine carbon cycling, mechanisms of horizontal gene transfer, and as a defense against phage attack.”

The vesicles first came to Chisholm’s attention in 2008 when Anne Thompson, then a graduate student, noticed little “blebs” on the surface of Prochlorococcus cells while using electron microscopy. Neither she nor Chisholm nor other ocean biologists who saw the photo were able to identify the spheres. But Biller, who joined Chisholm’s lab in 2010 after completing his graduate studies on soil bacteria, recognized them as vesicles, and began the study resulting in the Science paper.

In addition to Biller, Chisholm, and Thompson, other co-authors on the paper are Florence Schubotz and Roger Summons, of MIT’s Department of Earth, Atmospheric and Planetary Sciences, and Sara Roggensack, a former MIT lab technician who is now a graduate student at Tufts University.


Further Information

Join For Free

Access to this exclusive content is for Technology Networks Premium members only.

Join Technology Networks Premium for free access to:

  • Exclusive articles
  • Presentations from international conferences
  • Over 2,900+ scientific posters on ePosters
  • More Than 4,200+ scientific videos on LabTube
  • 35 community eNewsletters


Sign In



Forgotten your details? Click Here
If you are not a member you can join here

*Please note: By logging into TechnologyNetworks.com you agree to accept the use of cookies. To find out more about the cookies we use and how to delete them, see our privacy policy.

Related Content

Living a “Mixotrophic” Lifestyle
Some tiny plankton may have big effect on ocean’s carbon storage.
Wednesday, February 03, 2016
Mapping Regulatory Elements
Systematically searching DNA for regulatory elements indicates limits of previous thinking
Wednesday, February 03, 2016
Curing Disease by Repairing Faulty Genes
New delivery method boosts efficiency of CRISPR genome-editing system.
Wednesday, February 03, 2016
Living a “Mixotrophic” Lifestyle
Some tiny plankton may have big effect on ocean’s carbon storage.
Tuesday, February 02, 2016
Faster Drug Discovery?
Startup develops more cost-effective test for assessing how cells respond to chemicals.
Friday, January 29, 2016
No More Insulin Injections?
Encapsulated pancreatic cells offer possible new diabetes treatment.
Tuesday, January 26, 2016
Engineering Foe into Friend
Bose Grant awardee Jacquin Niles aims to repurpose the malaria parasite for drug delivery.
Monday, January 25, 2016
Synthetic Antibody Detects Proteins
Research could lead to nanosensors that recognize fibrinogen, insulin, or other biomarkers.
Friday, January 15, 2016
Supply Chain
Chemists discover how a single enzyme maintains a cell’s pool of DNA building blocks.
Wednesday, January 13, 2016
Organ-on-a-Chip
In a step toward personalized drug testing, researchers coax human stem cells to form complex tissues.
Friday, January 08, 2016
Study Reveals Shared Behavior of Microbes And Electrons
Bacteria streaming through a lattice behave like electrons in a magnetic material.
Wednesday, January 06, 2016
Study Reveals Shared Behavior of Microbes and Electrons
Bacteria streaming through a lattice behave like electrons in a magnetic material.
Wednesday, January 06, 2016
Tracing a Cellular Family Tree
New technique allows tracking of gene expression over generations of cells as they specialize.
Wednesday, January 06, 2016
Global Reductions in Mercury Emissions Should Lead to Billions in Economic Benefits for U.S.
Benefits from international regulations may double those of domestic policy.
Monday, January 04, 2016
New Device Uses Carbon Nanotubes to Snag Molecules
Nanotube “forest” in a microfluidic channel may help detect rare proteins and viruses.
Tuesday, December 22, 2015
Scientific News
Natural Protein Points to New Inflammation Treatment
Findings may offer insight to effective treatments for inflammatory diseases, such as rheumatoid arthritis, psoriasis, and multiple sclerosis.
Genetic Cause of Rare Allergy
Institute has identified a genetic mutation responsible for a rare form of inherited hives induced by vibratory urticaria.
Battery Component Found to Harm Key Soil Microorganism
The material at the heart of the lithium ion batteries that power electric vehicles, laptop computers and smartphones has been shown to impair a key soil bacterium, according to new research.
Keeping Tumor Growth at Bay
Engineers at Washington University in St. Louis found a way to keep a cancerous tumor from growing by using nanoparticles of the main ingredient in common antacid tablets.
Natural Protein Points to New Inflammation Treatment
Findings may offer insight to effective treatments for inflammatory diseases, such as rheumatoid arthritis, psoriasis, and multiple sclerosis.
Mitochondria Shown to Trigger Cell Ageing
An international team of scientists has for the first time shown that mitochondria, the batteries of the cells, are essential for ageing.
Cancer Cells Kill Off Healthy Neighbours
Cancer cells create space to grow by killing off surrounding healthy cells, according to UK researchers working with fruit flies.
Validating the Accuracy of CRISPR-Cas9
IBS Researchers create multiplex Digenome-seq to find errors in CRISPR-Cas9 processes.
Cancer Drug Target Visualized at Atomic Resolution
New study using cryo-electron microscopy shows how potential drugs could inhibit cancer.
Genetic Mechanism Behind Cancer-Causing Mutations
Researchers at Indiana University has identified a genetic mechanism that is likely to drive mutations that can lead to cancer.
Scroll Up
Scroll Down
Skyscraper Banner

Skyscraper Banner
Go to LabTube
Go to eposters
 
Access to the latest scientific news
Exclusive articles
Upload and share your posters on ePosters
Latest presentations and webinars
View a library of 1,800+ scientific and medical posters
2,900+ scientific and medical posters
A library of 2,500+ scientific videos on LabTube
4,200+ scientific videos
Close
Premium CrownJOIN TECHNOLOGY NETWORKS PREMIUM FOR FREE!