Axial Dynamics, Stability, and Interspecies Similarity of Bacterial Community Structure in the Highly Compartmentalized Gut of Soil-Feeding Termites ( Cubitermes spp.)

Abstract

The highly compartmentalized gut of soil-feeding termites is characterized by pronounced axial dynamics in physicochemical conditions and microbial processes. The hindgut of soil-feeding termites is highly compartmentalized and characterized by pronounced axial dynamics of oxygen, intestinal pH, and redox potential (1,3,4,14) and of microbial processes such as hydrogen production, methanogenesis, and reductive acetogenesis (26,29). Recent studies have provided strong evidence for an important role of the special physicochemical gut conditions and the pronounced intestinal microbiota in the chemical and microbial transformation of organic matter and microbial biomass during gut passage (11,12,13).A study of the phylogenetic diversity and axial distribution of microorganisms in the intestinal tract of Cubitermes orthognathus revealed that this variety of physicochemical conditions is reflected in the diversity of microbial communities in the different gut compartments and provided first evidence for the presence of a specific intestinal bacterial community (27).Although sequencing and phylogenetic analysis of cloned 16S rRNA genes provides information on the different phylotypes in a given community, the effort and costs involved in this approach limit investigations of changes in the structure of complex microbial communities over space and time. Molecular fingerprinting methods such as denaturing gradient gel electrophoresis (8,21,22) and terminal restriction fragment length polymorphism (T-RFLP) (9,18,19) analyses avoid these problems and allow the comparison of microbial communities in a larger number of samples, which has made these methods well-established tools in microbial ecology.A recent study combining clone analysis and T-RFLP to investigate archaeal community structure in the gut of the soil-feeding termite C. orthognathus provided evidence for pronounced differences among the microbiota not only between the gut and the ingested soil, but also among the different compartments of the intestinal tract (9). Based on the information on the phylogenetic diversity of the bacterial microbiota in the major gut compartments of C. orthognathus described in the companion paper (27), the present study employed T-RFLP analysis to follow changes in the bacterial community structure of ingested soil during gut passage. Comparing the terminal restriction fragment patterns of the homologous gut segments of three different species of Cubitermes, the study also addressed questions regarding the specificity of the gut microbiota for the compartments and the temporal stability of gut microbial communities during maintenance of termites under laboratory conditions. MATERIALS AND METHODSTermites and DNA extraction. Cubitermes orthognathus Emerson was collected in grassland near Busia, and Cubitermes ugandensis Fuller was collected in a glade of the Kakamega rainforest; both sites are located in the highlands of Western Kenya. Species were identified by Julius Muli, National Museums of Kenya. Cubitermes niokoloensis was coll...

From Structure to Function: the Ecology of Host-Associated Microbial Communities

“…Like that of the bovine rumen, the termite gut microbial community has garnered attention due to its enzymatic profile (35,308). These communities contain archaea, fungi, protists, and dozens to hundreds of bacterial taxa, several of which are unique to the termite gut, and likely contain more novel species (31,137,138,185,242,297,298,369). Bacterial members of these communities affiliate with more than 15 phyla, including the Spirochaetes, Fibrobacteres, Proteobacteria, CFB, Firmicutes, and Actinobacteria (137,242,297,298,369).…”

Phylogenetic Analysis of the Gut Bacterial Microflora of the Fungus-Growing TermiteOdontotermes formosanus

“…[3][4][5][6][7][8] Recently, Hongoh et al 9) performed comparative analysis of the bacterial community in the gut of wood-feeding termites, Microcerotermes and Reticulitermes species, based on clonal 16S rRNA genes, and showed that the community structure is basically consistent within a termite genus, and that a majority of the clones formed monophyletic clusters with sequences from other termite species. These results support the coevolution of gut bacteria and host termites, and imply the existence of bacterial lineages indispensable to their wood-feeding life style.…”

Molecular Phylogenetic Diversity of the Bacterial Community in the Gut of the TermiteCoptotermes formosanus

“…Studies using rRNA-based techniques such as rRNA gene clone sequencing, 5) terminal restriction fragment length polymorphisms (T-RFLP) analysis, 6) and fluorescence in situ hybridization (FISH) 7) have shown that the termite gut is a rich reservoir of novel and diverse microorganisms, and highly compartmentalized beyond our expectations, and have also indicated that our knowledge of the relevant ecosystem is still insufficient for comprehensive understanding of this symbiosis.…”