Morphology of the Digestive System in the Wood-Feeding Termite Nasutitermes takasagoensis (Shiraki) [Isoptera: Termitidae]

Tokuda, Gaku; Nakamura, Tomoko; Murakami, Ryutaro; Yamaoka, Ikuo

doi:10.2108/zsj.18.869

Cited by 24 publications

(15 citation statements)

References 23 publications

(26 reference statements)

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“…(11), it is likely that the dominance of these bacteria is consistent through the genera Microcerotermes and Nasutitermes. Although the gut bacterial communities of Nasutitermes termites, including N. takasagoensis, have often been studied using microscopy, no reports have referred to these bacteria (6,8,29,41). This might be due to the apparent similarity of their morphologies with those of small spirochetes.…”

Section: Discussionmentioning

confidence: 99%

Phylogenetic Diversity, Localization, and Cell Morphologies of Members of the Candidate Phylum TG3 and a Subphylum in the PhylumFibrobacteres, Recently Discovered Bacterial Groups Dominant in Termite Guts

Hongoh

Deevong

Hattori

et al. 2006

Appl Environ Microbiol

100

119

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Recently we discovered two novel, deeply branching lineages in the domainHere, we report on the specific detection of these bacteria, the candidate phylum TG3 (Termite Group 3) and a subphylum in the phylum Fibrobacteres, by fluorescence in situ hybridization in the guts of the wood-feeding termites Microcerotermes sp. and Nasutitermes takasagoensis. Both bacterial groups were detected almost exclusively from the luminal fluid of the dilated portion in the hindgut. Each accounted for approximately 10% of the total prokaryotic cells, constituting the second-most dominant groups in the whole-gut microbiota. The detected cells of both groups were in undulate or vibroid forms and apparently resembled small spirochetes. The cell sizes were 0.2 to 0.4 by 1.3 to 6.0 m and 0.2 to 0.3 by 1.3 to 4.9 m in the TG3 and Fibrobacteres, respectively. Using PCR screenings with specific primers, we found that both groups are distributed among various termites. The obtained clones formed monophyletic clusters that were delineated by the host genus rather than by the geographic distance, implying a robust association between these bacteria and host termites. TG3 clones were also obtained from a cockroach gut, lake sediment, rice paddy soil, and deep-sea sediments. Our results suggest that the TG3 and Fibrobacteres bacteria are autochthonous gut symbionts of various termites and that the TG3 members are also widely distributed among various other environments.Termites harbor an abundance and diversity of gut bacteria, which are thought to play essential roles in the carbon and nitrogen metabolism of their host termites (4, 26). Recent culture-independent analyses have revealed that the bacterial gut microbiota comprises many termite-specific lineages that are as yet uncultured (11-13, 27, 33, 35, 39). Among them, the candidate phylum Termite Group I (TG1) was first recognized in our previous study as a novel, deeply branching lineage specific to termites (27) and later found to constitute a new phylum, together with clones from various environments (13, 15). Now, the termite-specific cluster in this candidate phylum has been partly characterized as endosymbionts of gut protists in various lower termites (28, 38), whereas no isolate exists so far from this phylum. In higher termites, which generally lack gut symbiotic protists and harbor only prokaryotes (in contrast to lower termites that harbor both), there have been found other novel, deeply branching lineages in the domain Bacteria.Using clonal analyses of 16S rRNA, we recently discovered a novel phylum-level cluster, temporarily named TG3 (Termite Group 3), and a novel subphylum-level cluster in the phylum Fibrobacteres (designated Fibrobacteres subphylum 2 in this study) from the guts of the wood-feeding higher termites Microcerotermes spp. (11). Each group accounted for approximately 10% of the analyzed clones, constituting the second-most dominant groups, together with the orders Bacteroidales and Clostridiales, following the predominant genus, Treponema. The candidate phylum...

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Section: Discussionmentioning

confidence: 99%

Phylogenetic Diversity, Localization, and Cell Morphologies of Members of the Candidate Phylum TG3 and a Subphylum in the PhylumFibrobacteres, Recently Discovered Bacterial Groups Dominant in Termite Guts

Hongoh

Deevong

Hattori

et al. 2006

Appl Environ Microbiol

100

119

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“…Digestion begins with the mechanical grinding of wood into particles smaller than 50 lm . Drastic downsizing of wood particles (to 10-20 lm) has recently been reported in the foregut of lower termite Coptotermes formosanus (Fujita et al 2010) in addition to the midgut of higher termite Nasutitermes takasagoensis (Tokuda et al 2001). Cellulolytic enzymes synthesized by the salivary glands are secreted in the foregut, where they act on crystalline and amorphous cellulose (Watanabe et al 1998).…”

Section: Fiber Digestion By Wood-eating Termitesmentioning

confidence: 99%

“…The paunch, a microbe-packed enlarged hindgut compartment, is known as the fermentation chamber and the site of cellulolytic symbiosis (Hogan et al 1988a;Noirot 1995;Noirot and Noirot-Timothée 1969). Although some microbes colonize the midgut and rectum, their contribution to wood digestion seems negligible compared to those of the paunch (Tokuda et al 2001). The paunch region has the most favorable conditions for microbial fermentation with a redox potential ranging from -50 to -270 mV and pH from 6 to 7.5 (Brune and Friedrich 2000).…”

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confidence: 99%

Animal digestive strategies versus anaerobic digestion bioprocesses for biogas production from lignocellulosic biomass

Bayané

Guiot

2010

Rev Environ Sci Biotechnol

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Herbivorous mammals and wood-eating insects are fairly effective in the digestion of plant polymers, such as lignocellulosics. In order to improve methane production from the lignocellulosic biomass, several kinds of anaerobic digestion processes derived from animal models have been devised. However, the rates of biodegradation occurring in the anaerobic bioreactors still remain lower than in animal guts. The effectiveness of the digestive systems of those animals results from the concerted action of the various enzymes (e.g. cellulases, xylanases, esterases, ligninases) produced in their guts as well as their integration with mechanical and chemical actions. Powerful pretreatment (prefermentation) operations are integrated to and support efficiently the microbial fermentation system, e.g. the rumination (i.e. mechanical) in ruminants and the secretion of endogenous cellulases (i.e. enzymatic) or the alkaline treatment (chemical) at mid-way in xylophagous insects. The oxygen gradients along the gastrointestinal tract may also stimulate the hydrolytic activities of some microbial populations. In addition, the solid retention time, the digesta flow and the removal of the end-products are well ordered to enable animals to thrive on a complex polymer such as lignocellulose. At the same time, technologies were developed to degrade lignocellulosic biomass, such as the rumen derived anaerobic digestion (RUDAD) process and the rumen simulating technique (RUSITEC), more elaborated and using rumen microbial consortia. Overall, they showed that the fermentation taking place in the rumen fermentation and even in the hindgut are biological processes that go beyond the limited environmental conditions generally found in anaerobic digesters. Hence, knowledge on herbivores' digestion mechanisms might be better exploited in the design and operation of anaerobic digesters. This literature review is a cross-analysis of the relevant information about the digestive strategies of herbivorous and wood-eating animals and the bioengineering techniques in lignocelluloses degradation. The aim is to highlight strategies of animals' digestion simulation for more effective anaerobic digestion of lignocellulosic compounds and other solid residues.The main structural polysaccharides of plant tissues, cellulose and hemicelluloses, are linked with lignin and together called lignocellulose. Lignocellulosic biomass is more and more considered as a potential

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“…1). The mixed segment consists of mesenteric and proctodeal epithelial tissues (Bignell et al, 1983;Tokuda et al, 2001). Although the exact function of the mixed segment is still ambiguous, some physiological characteristics have been reported.…”

Section: Introductionmentioning

confidence: 99%

“…It has been proposed that the mesenteric epithelium of the mixed segment secretes a potassium-rich fluid into the gut lumen (Bignell et al, 1983). The mesenteric columnar cells in the mixed segment have extensive basal membrane invaginations and well-developed mitochondria (Tokuda et al, 2001).…”

Section: Introductionmentioning

confidence: 99%

Predominant expression and activity of vacuolar H+-ATPases in the mixed segment of the wood-feeding termite Nasutitermes takasagoensis

Kumara

Saitoh

Aoyama

et al. 2015

Journal of Insect Physiology

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Morphology of the Digestive System in the Wood-Feeding Termite Nasutitermes takasagoensis (Shiraki) [Isoptera: Termitidae]

Cited by 24 publications

References 23 publications

Phylogenetic Diversity, Localization, and Cell Morphologies of Members of the Candidate Phylum TG3 and a Subphylum in the PhylumFibrobacteres, Recently Discovered Bacterial Groups Dominant in Termite Guts

Phylogenetic Diversity, Localization, and Cell Morphologies of Members of the Candidate Phylum TG3 and a Subphylum in the PhylumFibrobacteres, Recently Discovered Bacterial Groups Dominant in Termite Guts

Animal digestive strategies versus anaerobic digestion bioprocesses for biogas production from lignocellulosic biomass

Predominant expression and activity of vacuolar H+-ATPases in the mixed segment of the wood-feeding termite Nasutitermes takasagoensis

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