Nitrogen Fixation by Bacteria from the Hindgut of Termites

French, J. R. J.; Turner, G. L.; Bradbury, J. F.

doi:10.1099/00221287-95-2-202

Cited by 88 publications

(49 citation statements)

References 9 publications

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“…The prevalence of nitrogen fixation by bacterial symbionts of protists supports this hypothesis, but the amount of nitrogen supplied to protists by their symbionts, the mechanism, the type of molecule supplied, and the dependency of the protists on this nitrogen supply are not known. Free-living hindgut bacteria probably also fix nitrogen (38)(39)(40), but most of the nitrogen fixation activity in the hindguts is likely performed by bacterial symbionts of protists (37,41), a conclusion supported by our analysis of free-living bacteria in the hindguts of Cryptocercus (Fig. 6D).…”

Section: Discussionsupporting

confidence: 70%

“…Molecular and genomic data indicate that hindgut symbionts from wood-eating termites and cockroaches possess a diversity of nitrogenase genes (16,(33)(34)(35)(36)(37), but actual nitrogen fixation by specific symbionts has rarely been demonstrated. For instance, a few cultivated bacteria have been shown to fix nitrogen, but these are likely not the dominant nitrogen fixers in the hindgut (37)(38)(39)(40). As well, in using cultivationindependent methods, results of PCR, acetylene reduction, and 15 N 2 incorporation assays suggest that the majority of nitrogen fixation in the hindguts of Hodotermopsis sjoestedti is performed by spirochete endosymbionts of Eucomonympha (41).…”

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confidence: 99%

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Genome Evolution and Nitrogen Fixation in Bacterial Ectosymbionts of a Protist Inhabiting Wood-Feeding Cockroaches

Tai

Carpenter

Weber

et al. 2016

Appl Environ Microbiol

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By combining genomics and isotope imaging analysis using high-resolution secondary ion mass spectrometry (NanoSIMS), we examined the function and evolution of Bacteroidales ectosymbionts of the protist Barbulanympha from the hindguts of the wood-eating cockroach Cryptocercus punctulatus. In particular, we investigated the structure of ectosymbiont genomes, which, in contrast to those of endosymbionts, has been little studied to date, and tested the hypothesis that these ectosymbionts fix nitrogen. Unlike with most obligate endosymbionts, genome reduction has not played a major role in the evolution of the Barbulanympha ectosymbionts. Instead, interaction with the external environment has remained important for this symbiont as genes for synthesis of transporters, outer membrane proteins, lipopolysaccharides, and lipoproteins have been retained. The ectosymbiont genome carried two complete operons for nitrogen fixation, a urea transporter, and a urease, indicating the availability of nitrogen as a driving force behind the symbiosis. NanoSIMS analysis of C. punctulatus hindgut symbionts exposed in vivo to 15 N 2 supports the hypothesis that Barbulanympha ectosymbionts are capable of nitrogen fixation. This genomic and in vivo functional investigation of protist ectosymbionts highlights the diversity of evolutionary forces and trajectories that shape symbiotic interactions. IMPORTANCEThe ecological and evolutionary importance of symbioses is increasingly clear, but the overall diversity of symbiotic interactions remains poorly explored. In this study, we investigated the evolution and nitrogen fixation capabilities of ectosymbionts attached to the protist Barbulanympha from the hindgut of the wood-eating cockroach Cryptocercus punctulatus. In addressing genome evolution of protist ectosymbionts, our data suggest that the ecological pressures influencing the evolution of extracellular symbionts clearly differ from intracellular symbionts and organelles. Using NanoSIMS analysis, we also obtained direct imaging evidence of a specific hindgut microbe playing a role in nitrogen fixation. These results demonstrate the power of combining NanoSIMS and genomics tools for investigating the biology of uncultivable microbes. This investigation paves the way for a more precise understanding of microbial interactions in the hindguts of wood-eating insects and further exploration of the diversity and ecological significance of symbiosis between microbes.

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Section: Discussionsupporting

confidence: 70%

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confidence: 99%

Genome Evolution and Nitrogen Fixation in Bacterial Ectosymbionts of a Protist Inhabiting Wood-Feeding Cockroaches

Tai

Carpenter

Weber

et al. 2016

Appl Environ Microbiol

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“…were reported as symbiotic microbes involved in the maintenance of normal nitrogen levels in the guts of termites and fruit flies (Ceratitis capitata) using different metabolic mechanisms, including nitrogen fixation [36][37][38]. Citrobacter freundii was also isolated from D. micans [39].…”

Section: Bacterial Community Structurementioning

confidence: 99%

Influence of Starvation on the Structure of Gut-Associated Bacterial Communities in the Chinese White Pine Beetle (Dendroctonus armandi)

Zhang

et al. 2016

Forests

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This study investigated the influence of starvation on the structure of the gut bacterial community in the Chinese white pine beetle (Dendroctonus armandi). A total of 14 operational taxonomic units (OTUs 0.03 ) clusters belonging to nine genera were identified. Denaturing gradient gel electrophoresis (DGGE) profiles of bacterial PCR-amplified 16S rRNA gene fragments from the guts of starved male and female adults revealed that the bacterial community diversity increased after starvation. The dominant genus Citrobacter decreased significantly, whereas the genus Serratia increased in both starved female and starved male adults. The most predominant bacterial genus in D. armandi adults was Citrobacter, except for starved male adults, in which Serratia was the most abundant genus (27%). Our findings reveal that starvation affects gut bacterial dynamics in D. armandi, as has been observed in other insect species.

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“…The organisms such as Citrobacter fruendii, Lactococcus sp, Enterobacter sp, Paenibacillus sp were isolated successfully and their role in soil fertility is tabulated in table 2. Citrobacter sp acts as nitrogen fixing organism in fixing atmospheric nitrogen into the soil [11] and as methanogenic organism in the production of methane [12]. Lactococcus sp acts as fermentative bacteria which help in extra molecular digestion [13].…”

Section: Resultsmentioning

confidence: 99%

Termite Soil as Bio-Indicator of Soil Fertility

Nithyatharani¹,

Kavitha²

2018

IJRASET

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Termites are a common group of insects which acts as bio indicator of soil fertility. Termites play a major role in nitrogen fixation, acetogenesis, methanogenesis, soil transportation and nutrient movement. The objective of the study is to determine the physiochemical parameters of soil in comparison with termite mound soil and chemically fertilized soil and this study also deals with the isolation and identification of microorganisms from termite soil. This study also involves the action of termites in soil fertility by pot culture technique. The physical parameters such as pH, moisture, texture, electrical conductivity and chemical parameters such as carbon, nitrogen, calcium, magnesium, phosphorus and potassium showed increased value when compared with chemically fertilized soil. Organisms such as Citrobacter fruendii, Paenibacillus sp, Enterobacter sp, Lactococcus sp were isolated successfully. Pot culture technique showed that the plant grown in termite soil shows more growth compared with chemically fertilized soil. The results suggested that termite soil has more significant factors responsible for plant growth in comparison with chemically fertilized soil.

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Nitrogen Fixation by Bacteria from the Hindgut of Termites

Cited by 88 publications

References 9 publications

Genome Evolution and Nitrogen Fixation in Bacterial Ectosymbionts of a Protist Inhabiting Wood-Feeding Cockroaches

Genome Evolution and Nitrogen Fixation in Bacterial Ectosymbionts of a Protist Inhabiting Wood-Feeding Cockroaches

Influence of Starvation on the Structure of Gut-Associated Bacterial Communities in the Chinese White Pine Beetle (Dendroctonus armandi)

Termite Soil as Bio-Indicator of Soil Fertility

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