Development of an ecophysiological model for Diplosphaera colotermitum TAV2, a termite hindgut Verrucomicrobium

Abstract

Termite hindguts are populated by a dense and diverse community of microbial symbionts working in concert to transform lignocellulosic plant material and derived residues into acetate, to recycle and fix nitrogen, and to remove oxygen. Although much has been learned about the breadth of microbial diversity in the hindgut, the ecophysiological roles of its members is less understood. In this study, we present new information about the ecophysiology of microorganism Diplosphaera colotermitum strain TAV2, an autochthonous member of the Reticulitermes flavipes gut community. An integrated high-throughput approach was used to determine the transcriptomic and proteomic profiles of cells grown under hypoxia (2% O 2 ) or atmospheric (20% O 2 ) concentrations of oxygen. Our results revealed that genes and proteins associated with energy production and utilization, carbohydrate transport and metabolism, nitrogen fixation, and replication and recombination were upregulated under 2% O 2 . The metabolic map developed for TAV2 indicates that this microorganism may be involved in biological nitrogen fixation, amino-acid production, hemicellulose degradation and consumption of O 2 in the termite hindgut. Variation of O 2 concentration explained 55.9% of the variance in proteomic profiles, suggesting an adaptive evolution of TAV2 to the hypoxic periphery of the hindgut. Our findings advance the current understanding of microaerophilic microorganisms in the termite gut and expand our understanding of the ecological roles for members of the phylum Verrucomicrobia.

Hologenome analysis of two marine sponges with different microbiomes

“…Differential expression analysis of the microbiome genes identified several intriguing protein domains that were significantly over-represented in XT over SC (Fig. 4 and Additional file 14 ), including: the “Xylose isomerase-like TIM barrel” domain (PF01261), which is thought to be involved in the symbiosis of microbes with leguminous plants and the termite hindgut [ 39 , 40 ]; the “HicB family” domain (PF05534), which is related to pilus formation and required for niche invasion [ 41 ]; the “PIN domain” (PF01850), which is found in the toxin-antitoxin operons of prokaryotes [ 42 ]; and the “Mycoplasma protein of unknown function” domain (PF03382), which has been detected in many pathogenic bacteria [ 43 ].

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The Gut Microbiota of Termites: Digesting the Diversity in the Light of Ecology and Evolution

“…Therefore, the isolation of facultative and strictly aerobic bacteria from termite guts is not surprising. Particularly, the acetate-oxidizing microaerophiles colonizing the hindgut wall appear to be well adapted to the hypoxic conditions in the periphery of the hindgut (49,122,123). Oxygen is used as an electron sink also by fermenting bacteria, as indicated by the shift from propionate to acetate during the metabolism of lactate (16).…”

Characterization of Outer Membrane Proteome of Akkermansia muciniphila Reveals Sets of Novel Proteins Exposed to the Human Intestine

“…There is limited information available on the membrane structure and composition of A. muciniphila , and most reports have focused on in silico analysis of Verrucomicrobia membranes, instead of experimental approaches ( Santarella-Mellwig et al, 2010 ; Kamneva et al, 2012 ; Speth et al, 2012 ). Recently, the proteome of a termite hindgut representative of the Verrucomicrobia, Diplosphaera colotermitum TAV2, was experimentally studied, but this report did not focus on membrane proteins ( Isanapong et al, 2013 ). The presence of OM biomarkers, including genes involved in lipopolysaccharide (LPS) insertion, in the genome of A. muciniphila was confirmed computationally ( Speth et al, 2012 ).…”