
NSF Org: |
IOS Division Of Integrative Organismal Systems |
Recipient: |
|
Initial Amendment Date: | March 20, 2020 |
Latest Amendment Date: | July 8, 2020 |
Award Number: | 1940165 |
Award Instrument: | Standard Grant |
Program Manager: |
Joanna Shisler
jshisler@nsf.gov (703)292-5368 IOS Division Of Integrative Organismal Systems BIO Directorate for Biological Sciences |
Start Date: | May 1, 2020 |
End Date: | April 30, 2023 (Estimated) |
Total Intended Award Amount: | $476,483.00 |
Total Awarded Amount to Date: | $476,483.00 |
Funds Obligated to Date: |
|
History of Investigator: |
|
Recipient Sponsored Research Office: |
101 COMMONWEALTH AVE AMHERST MA US 01003-9252 (413)545-0698 |
Sponsor Congressional District: |
|
Primary Place of Performance: |
MA US 01035-9450 |
Primary Place of
Performance Congressional District: |
|
Unique Entity Identifier (UEI): |
|
Parent UEI: |
|
NSF Program(s): | Symbiosis Infection & Immunity |
Primary Program Source: |
|
Program Reference Code(s): |
|
Program Element Code(s): |
|
Award Agency Code: | 4900 |
Fund Agency Code: | 4900 |
Assistance Listing Number(s): | 47.074 |
ABSTRACT
Shipworms live in the ocean and are related to clams. They are some of a very few animals in the world that can eat wood. They also play an important role in nature by recycling the carbon in wood. It is estimated that between 2 - 5% of the world?s woody plant material is eaten by shipworms. The goal of this project is to understand how shipworms eat wood. Digesting wood?s complex structure isn?t easy. Scientists know that relatively large enzymes alone cannot break down wood, because wood molecules are packed too tightly together for enzymes to enter. Shipworms farm bacteria in their gills, and these bacteria have recently been found to produce very small compounds that may move into the shipworm gut where the small compounds can make powerful oxygen radicals to digest the wood. Making the oxygen radicals is proposed as the first step needed to break open the wood structure into smaller pieces. Then, in a second step, enzymes can completely digest the wood. Previously, the compounds that can make the oxygen radicals were found only in some types of fungi that also digest wood. Scientists believe that studying this shipworm chemistry may open up new knowledge about how carbon is cycled in our oceans, and may also lead to new discoveries on ways to make biofuels and renewable materials. The researchers involved in this project also believe strongly in supporting young, underrepresented female scientists and will be running educational opportunities for girls in a local town.
Shipworms are the principle degraders of lignocellulose across the world?s oceans; they cause billions of dollars of damage to wooden structures (boats, piers and sea-defenses), but they also play a major role in carbon-cycling. The relative simplicity of their symbiotic communities and the unique compartmentalization of their digestive system make shipworm symbiosis a tractable counterpoint to terrestrial xylotrophs (e.g., fungi, termites). The goal of this project is to explore the unknown mechanisms of wood digestion in shipworms by examining how these animals interact with their gill endosymbionts and determining specifically whether a symbiont-mediated chemical degradation mechanism is active in the host gut. There are three approaches to reach this goal. The first approach is to determine how low molecular-weight (LMW) metabolites from shipworm gill symbionts may be activated in the host gut to generate a non-enzymatic system for lignocellulose deconstruction. This involves mapping the location of LMW metabolites in the gill and digestive system. The second approach will examine gut compartmentalization for pH environments that may promote symbiont-mediated iron reduction, redox-cycling and the generation of hydroxyl radicals associated with CMF reactions. It will also assess the spatial arrangement and compartmentalization of shipworm anatomy, and identify and map structures linking the gill endosymbionts with the digestive tract. The third approach will compare and analyze the digestive products and waste material from shipworms grown on isotopically-labelled wood. Understanding the basis of wood digestion may allow discovery of candidate catalytic/enzymatic systems and development of new strategies for bio-based materials and biofuel production.
This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
PUBLICATIONS PRODUCED AS A RESULT OF THIS RESEARCH
Note:
When clicking on a Digital Object Identifier (DOI) number, you will be taken to an external
site maintained by the publisher. Some full text articles may not yet be available without a
charge during the embargo (administrative interval).
Some links on this page may take you to non-federal websites. Their policies may differ from
this site.
PROJECT OUTCOMES REPORT
Disclaimer
This Project Outcomes Report for the General Public is displayed verbatim as submitted by the Principal Investigator (PI) for this award. Any opinions, findings, and conclusions or recommendations expressed in this Report are those of the PI and do not necessarily reflect the views of the National Science Foundation; NSF has not approved or endorsed its content.
Shipworms, historically known for causing extensive damage to wooden ships and coastal structures, play a key role in carbon and nutrient cycling of woody biomass in aquatic ecosystems. Despite extensive research over more than a century, the exact mechanisms underlying their ability to digest wood have remained elusive, particularly regarding the degradation of lignin, a major component of wood that resists enzymatic breakdown. We employed a combination of microbial culture, metagenomic, and “FISH-probe” (fluorescent in-situ hybridization) microscopy analyses to explore previously overlooked aspects of their digestive system in the species Teredo navalis. Notably, we identify the presence of bacterial symbionts within the “typhlosole”, a specialized structure within the main wood digestive organ (cecum), challenging the long-held belief that shipworm foreguts are nearly sterile environments. The discovery of Alteromonas species in "bacterial clusters" within the typhlosole suggests a symbiotic relationship that may play a crucial role in the digestion of woody substrates, offering a potential explanation for the shipworm's ability to degrade lignocellulose without the production of host or gill symbiont ligninases. It is unknown why prior researchers did not find these symbionts in the typhlosole as more recent prior work has used similar tools to those employed in our current study, including FISH probes. However, over the past century, prior researchers who paved the way for this work did not have the advanced tools needed to visualize and label bacteria.
These findings provide valuable insights into both the digestive physiology and host defense of shipworm, and highlight the complex interactions between marine organisms and their symbiotic partners. Our findings suggests that the typhlosole in other related organisms. including mollusks, annelids, and tunicates, might also harbor symbionts, and we believe that this should be explored more thoroughly in those species Additionally, this study opens new avenues for research into the ecological and biotechnological applications of shipworms and their gut symbionts, potentially revolutionizing our understanding of lignocellulose degradation in marine environments.
"This Project Outcomes Report for the General Public is displayed verbatim as submitted by the Principal Investigator (PI) for this award. Any opinions, findings, and conclusions or recommendations expressed in this Report are those of the PI and do not necessarily reflect the views of the National Science Foundation; NSF has not approved or endorsed its content."
Last Modified: 04/23/2024
Modified by: Barry S Goodell
Please report errors in award information by writing to: awardsearch@nsf.gov.