This Article
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Similar articles in this journal
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrowReprints and Permissions
Right arrow Copyright Information
Right arrow Books from ASM Press
Right arrow MicrobeWorld
Citing Articles
Right arrow Citing Articles via HighWire
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by Deming, J. W.
Right arrow Articles by Colwell, R. R.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Deming, J. W.
Right arrow Articles by Colwell, R. R.
Agricola
Right arrow Articles by Deming, J. W.
Right arrow Articles by Colwell, R. R.

 Previous Article  |  Next Article 

Appl Environ Microbiol. 1982 November; 44(5): 1222-1230
Copyright © 1982, American Society for Microbiology. All Rights Reserved.

Barophilic Bacteria Associated with Digestive Tracts of Abyssal Holothurians

Jody W. Deming{dagger} and Rita R. Colwell

Department of Microbiology, University of Maryland, College Park, Maryland 20742

ABSTRACT

Abyssal holothurians and sediment samples were collected at depths of 4,430 to 4,850 m in the Demerara abyssal plain. Bacterial concentrations in progressive sections of the holothurian digestive tract, as well as in surrounding surface sediments, were determined by epifluorescence microscopy. Total bacterial counts in sediments recently ingested by the animals were 1.5- to 3-fold higher than in surrounding sediments at the deepest station. Lowest counts were observed consistently in the foregut, where the digestive processes of the holothurian are believed to occur. In most animals, counts increased 3- to 10-fold in the hindgut. Microbial activity at 3°C and in situ and atmospheric pressure were determined for gut and sediment samples by measuring the utilization of [14C]glutamic acid, the doubling time of the mixed-population of culturable bacteria, and the percentage of the total bacterial count responsive to yeast extract in the presence of nalidixic acid, using epifluorescence microscopy. A barophilic microbial population, showing elevated activity under deep-sea pressure, was detected by all three methods in sediments removed from the hindgut. Transmission electron micrographs revealed intact bacteria directly associated with the intestinal lining only in the hindgut. The bacteria are believed to be carried as an actively metabolizing, commensal gut flora that transforms organic matter present in abyssal sediments ingested by the holothurian. Using data obtained in this study, it was calculated that sediment containing organic matter altered by microbial activity cleared the holothurian gut every 16 h, suggesting that abyssal holothurians and their associated gut flora are important participants in nutrient cycles of the abyssal benthic ocean.

FOOTNOTES

{dagger} Present address: Chesapeake Bay Institute, Johns Hopkins University, Shady Side, MD 20764.

Appl Environ Microbiol. 1982 November; 44(5): 1222-1230
Copyright © 1982, American Society for Microbiology. All Rights Reserved.



This article has been cited by other articles:

  • Wirsen, C. O., Molyneaux, S. J. (1999). A Study of Deep-Sea Natural Microbial Populations and Barophilic Pure Cultures Using a High-Pressure Chemostat. Appl. Environ. Microbiol. 65: 5314-5321 [Abstract] [Full Text]  
  • DeLong, E., Yayanos, A. (1985). Adaptation of the membrane lipids of a deep-sea bacterium to changes in hydrostatic pressure. Science 228: 1101-1103 [Abstract]  


Copyright © 2009 by the American Society for Microbiology.   For an alternate route to Journals.ASM.org, visit: http://intl-journals.asm.org | More Info»