Friday, January 30, 2015
YOLO COUNTY NEWS
99 CENTS

Bacteria pair form link in nitrogen cycle

By
From page A8 | August 22, 2013 |

Two species of bacteria living on the ocean floor have teamed up in a unique symbiotic relationship to form a critical link in the Earth’s nitrogen cycle, reports a research team that includes two UC Davis microbiologists.

The scientists, led by researchers affiliated with the University of Southern California, published their findings about the novel bacterial partnership earlier this month in the journal Nature.

At the heart of the study are the long, thin, hairlike bacteria called Thioploca (meaning “sulfur braids” in Spanish) and the tiny anammox bacteria, which use ammonium and nitrite released by Thioploca as an energy source. Both species of bacteria dwell in the ocean floor off of the coast of Baja California as well as the Pacific coast of South America.

The Thioploca live as filaments inside sheaths that glide vertically through marine sediment, generating nitrite and “fixed” nitrogen. The anammox bacteria live in close association with, or piggy-back on, Thioploca, allowing them to consume the byproducts produced by Thioploca.

“All life — including microbes — rely upon one another to survive,” said UC Davis microbiologist Scott Dawson, a co-author on the paper. “A key ecological link in the global nitrogen cycle between microbes with these physiologies has been postulated for some time, yet this study provides the first direct evidence of this intimate, symbiotic association.”

Marissa Hirst, a graduate student in Dawson’s laboratory, provided molecular and microscopic evidence for the presence of anammox bacteria in close association with Thioploca. The research involved identifying anammox-specific genes as well as showing that anammox bacteria were found in Thioploca sheaths, using fluorescence microscopy.

Nitrogen is a prerequisite for photosynthesis and a crucial building block of life. It is abundant in Earth’s atmosphere but to be useful to most living organisms must be converted from its nonreactive atmospheric form into the biologically available, or “fixed,” form as ammonium.

The specialized organisms that carry out this nitrogen-conversion process are called nitrogen fixers. Other organisms use up the fixed nitrogen and convert it back to the atmospheric form of nitrogen, which is di-nitrogen gas.

Thioploca filaments store high concentrations of nitrate; the concentration of this valuable resource is several thousand-fold higher compared to that of the surrounding sediment. As Thioploca glides down vertically through the sediment, it encounters sulfide, which is used to produce fixed nitrogen or ammonium.

For most other bacteria, sulfide is a roadblock to metabolism, but Thioploca is able to react nitrate with sulfide, producing ammonium and nitrite, which the anammox then consumes and churns out as di-nitrogen gas. With the anammox cells living off of the Thioploca byproducts, both microbes thrive in a unique microbial niche where others perish.

The symbiosis between Thioploca and anammox does not cause widespread changes in the nitrogen cycle throughout the ocean; rather, it creates localized zones where fixed nitrogen is depleted more quickly from sediments than most scientists had expected.

— UC Davis News Service

Comments

comments

  • Recent Posts

  • Enter your email address to subscribe to this newspaper and receive notifications of new articles by email.

  • .

    News

    Suspected Ebola patient being treated at UCD Med Center

    By San Francisco Chronicle | From Page: A1

     
    Town hall focuses on Coordinated Care Initiative

    By Anne Ternus-Bellamy | From Page: A1

    Parents will get tools to help their children thrive in school

    By Enterprise staff | From Page: A1 | Gallery

     
    Need a new best friend?

    By Enterprise staff | From Page: A2 | Gallery

     
    Stanford University to get $50 million to produce vaccines

    By The Associated Press | From Page: A2

    Two more cases of measles in Northern California in children

    By The Associated Press | From Page: A2

     
    Dartmouth bans hard liquor

    By New York Times News Service | From Page: A2

     
    Vote for your favorites in Readers’ Choice poll

    By Enterprise staff | From Page: A3

    No bare bottoms, thanks to CommuniCare’s Diaper Drive

    By Special to The Enterprise | From Page: A3 | Gallery

     
    Storyteller relies on nature as his subject on Saturday

    By Enterprise staff | From Page: A3

    Still time to purchase tickets for DHS Cabaret

    By Enterprise staff | From Page: A3

     
    All voices welcome at sing-along Wednesday

    By Enterprise staff | From Page: A3

    Great Chefs Program will feature Mulvaney

    By Special to The Enterprise | From Page: A3

     
    Walkers head out three times weekly

    By Enterprise staff | From Page: A3Comments are off for this post

    Free tax preparation service begins Monday

    By Special to The Enterprise | From Page: A3

     
    February science fun set at Explorit

    By Lisa Justice | From Page: A6 | Gallery

     
    Take a photo tour of Cuba at Flyway Nights talk

    By Enterprise staff | From Page: A6 | Gallery

    See wigeons, curlews and meadowlarks at city wetlands

    By Special to The Enterprise | From Page: A8 | Gallery

     
    .

    Forum

    Time for bed … with Grandma

    By Creators Syndicate | From Page: B5

     
    Weigh quality of life, density

    By Letters to the Editor | From Page: A10

    Olive expert joins St. James event

    By Letters to the Editor | From Page: A10

     
    We’re grateful for bingo proceeds

    By Letters to the Editor | From Page: A10

    Tom Meyer cartoon

    By Debbie Davis | From Page: A10

     
    A ‘new deal’ for the WPA building

    By Special to The Enterprise | From Page: A10

     
    Protect root zone to save trees

    By Letters to the Editor | From Page: A10

    .

    Sports

    UCD men set new school D-I era win record

    By Bruce Gallaudet | From Page: B1 | Gallery

     
    UCD has another tough football schedule in 2015

    By Enterprise staff | From Page: B1

    Gould’s influence felt mightily in recent Super Bowls

    By Bruce Gallaudet | From Page: B1

     
    Mustangs hold off UCD women

    By Enterprise staff | From Page: B1 | Gallery

    Sharks double up Ducks

    By The Associated Press | From Page: B2 | Gallery

     
    Sports briefs: Watney, Woods start slow at TPC Scottsdale

    By Enterprise staff | From Page: B2

    Recall that first Aggie TV game, national title?

    By Bruce Gallaudet | From Page: B8 | Gallery

     
    .

    Features

    .

    Arts

    ‘Song of the Sea’ is an enchanting fable

    By Derrick Bang | From Page: A11 | Gallery

     
    ‘Artist’s Connection’ launches on DCTV

    By Special to The Enterprise | From Page: A11

     
    Gross’ paintings highlight a slice of Northern California

    By Enterprise staff | From Page: A12 | Gallery

    February show at YoloArts’ Gallery 625 is ‘Food for Thought’

    By Special to The Enterprise | From Page: A12 | Gallery

     
    .

    Business

    .

    Obituaries

    .

    Comics

    Comics: Friday, January 30, 2015

    By Creator | From Page: A9