Bacteroidales ectosymbionts of gut flagellates shape the nitrogen-fixing community in dry-wood termites.
Summary of "Bacteroidales ectosymbionts of gut flagellates shape the nitrogen-fixing community in dry-wood termites."
Although it is well documented that the lack of nitrogen in the diet of wood-feeding termites is compensated by the nitrogen-fixing capacity of their gut microbiota, the bacteria responsible for this activity are largely unknown. Here, we analyzed the diversity and expression of nitrogenase genes (homologs of nifH) in four species of dry-wood termites (Kalotermitidae), which thrive on a particularly nitrogen-poor resource. Although each species harbored a highly diverse suite of termite-specific homologs in their microliter-sized hindgut, only a core set related to nifH genes of Treponema and Azoarcus spp., 'Azobacteroides pseudotrichonymphae', the first member of the Bacteroidales identified as a diazotroph, and termite-gut-specific anfH genes of hitherto unknown origin were preferentially expressed. Transcription patterns corroborated that the populations of active diazotrophs differ fundamentally between termite genera. Capillary-picked suspensions of the flagellates Devescovina arta and Snyderella tabogae revealed that their bacterial ectosymbionts each possess two paralogs of nifH, which apparently have been acquired consecutively during evolution of Bacteroidales, but only one of them (anfH) is actively expressed. Transcription patterns correlated neither with the molybdenum content of the diet nor with intestinal hydrogen concentrations, measured with microsensors. We propose that the nitrogen-fixing community in different dry-wood termites is shaped by the symbionts of their specific flagellate populations. Our findings suggest that the diazotrophic nature of 'Armantifilum devescovinae' has an important role in the nitrogen metabolism of dry-wood termites and is the driving force of co-evolution with its flagellate host.
Affiliation
Department of Biogeochemistry, Max Planck Institute for Terrestrial Microbiology, Marburg, Germany.
Journal Details
This article was published in the following journal.
Name: The ISME journal
ISSN: 1751-7370
Pages:
Links
- PubMed Source: http://www.ncbi.nlm.nih.gov/pubmed/22189498
- DOI: http://dx.doi.org/10.1038/ismej.2011.194
Medical and Biotech [MESH] Definitions
Plant Root Nodulation
The formation of a nitrogen-fixing cell mass on PLANT ROOTS following symbiotic infection by nitrogen-fixing bacteria such as RHIZOBIUM or FRANKIA.
Cyanobacteria
A phylum of oxygenic photosynthetic bacteria comprised of unicellular to multicellular bacteria possessing CHLOROPHYLL a and carrying out oxygenic PHOTOSYNTHESIS. Cyanobacteria are the only known organisms capable of fixing both CARBON DIOXIDE (in the presence of light) and NITROGEN. Cell morphology can include nitrogen-fixing heterocysts and/or resting cells called akinetes. Formerly called blue-green algae, cyanobacteria were traditionally treated as ALGAE.
Leghemoglobin
A hemoglobin-like oxygen-binding hemeprotein present in the nitrogen-fixing root nodules of leguminous plants. The red pigment has a molecular weight approximately 1/4 that of hemoglobin and has been suggested to act as an oxido-reduction catalyst in symbiotic nitrogen fixation.
Nostoc Muscorum
A form-species of nitrogen-fixing CYANOBACTERIA, in the family Nostocaceae, order Nostocales.
Euglenida
A phylum of unicellular flagellates of ancient eukaryotic lineage with unclear taxonomy. They lack a CELL WALL but are covered by a proteinaceous flexible coat, the pellicle, that allows the cell to change shape. Historically some authorities considered them to be an order of protozoa and others classed them as ALGAE (some members have CHLOROPLASTS and some don't).
PubMed Articles
How close are we to nitrogen-fixing cereals?
Engineering nitrogen-fixing cereals is essential for sustainable food production for the projected global population of 9 billion people in 2050. This process will require engineering cereals for nodu...
Effects of three different PAHs on nitrogen-fixing bacterial diversity in mangrove sediment.
Polycyclic aromatic hydrocarbons (PAHs) are of great environmental and human health concerns due to their widespread occurrence, persistence and carcinogenic properties. There is now compelling eviden...
An experiment was conducted under laboratory conditions to investigate the effect of two systemic herbicides viz., pendimethalin and quizalofop, at their recommended field rates (1.0 kg and 50 g act...
Active nitrogen-fixing heterotrophic bacteria at and below the chemocline of the central Baltic Sea.
The Baltic Sea receives large nitrogen inputs by diazotrophic (N2-fixing) heterocystous cyanobacteria but the significance of heterotrophic N2 fixation has not been studied. Here, the diversity, abund...
BACKGROUND: Symbiotic nitrogen (N)-fixing trees are rare in late-successional temperate forests, even though these forests are often N limited. Two hypotheses could explain this paradox. The 'phylogen...
Clinical Trials
HIPWOODS - Health Effects Related to Exposure to Particle Pollution From Woodburning Stoves
The study intends to focus on health effects and symptoms related to particle exposure from wood burning stoves The objective is to determine whether moderate exposure to particles from w...
Woodsmoke Exposure and Cardiovascular Function
Air pollution is linked to respiratory and cardiovascular disease. Wood smoke is a common air in many parts of the world and previous studies indicate that wood smoke induce oxidative stre...
The study is designed to investigate the influence of parenteral nutrition (PN) with low nitrogen and calorie supply on the clinical outcome of patients after an operation compared to that...
The purpose of the study was to see if liquid nitrogen, a commonly used treatment for warts, is more effective if it is used alone, or if it is more effective if combined with cantharidin,...
Shape Up Somerville: Eat Smart Play Hard
Community-based environmental approach to obesity prevention targeting first, second, and third grade students in Somerville, MA.
