The chemistry of a termite fungus comb

1987 ◽  
Vol 98 (2) ◽  
pp. 247-256 ◽  
Author(s):  
M. A. Arshad ◽  
M. Schnitzer
Keyword(s):  
Fungus Comb

scholarly journals Lignocellulose pretreatment in a fungus-cultivating termite

2017 ◽  
Vol 114 (18) ◽  
pp. 4709-4714 ◽  
Author(s):  
Hongjie Li ◽  
Daniel J. Yelle ◽  
Chang Li ◽  
Mengyi Yang ◽  
Jing Ke ◽  
...  
Keyword(s):  
Cell Walls ◽  
2D Nmr ◽  
Lignocellulose Degradation ◽  
Plant Cell Walls ◽  
Radical Coupling ◽  
Feeding Experiments ◽  
Starting Point ◽  
Fungus Comb ◽  
Phenolic Polymer ◽  
Lignin Depolymerization

Depolymerizing lignin, the complex phenolic polymer fortifying plant cell walls, is an essential but challenging starting point for the lignocellulosics industries. The variety of ether– and carbon–carbon interunit linkages produced via radical coupling during lignification limit chemical and biological depolymerization efficiency. In an ancient fungus-cultivating termite system, we reveal unprecedentedly rapid lignin depolymerization and degradation by combining laboratory feeding experiments, lignocellulosic compositional measurements, electron microscopy, 2D-NMR, and thermochemolysis. In a gut transit time of under 3.5 h, in young worker termites, poplar lignin sidechains are extensively cleaved and the polymer is significantly depleted, leaving a residue almost completely devoid of various condensed units that are traditionally recognized to be the most recalcitrant. Subsequently, the fungus-comb microbiome preferentially uses xylose and cleaves polysaccharides, thus facilitating final utilization of easily digestible oligosaccharides by old worker termites. This complementary symbiotic pretreatment process in the fungus-growing termite symbiosis reveals a previously unappreciated natural system for efficient lignocellulose degradation.

The inoculation of newly formed fungus comb withTermitomyces inMacrotermes colonies (Isoptera, Macrotermitinae)

1989 ◽  
Vol 36 (4) ◽  
pp. 328-338 ◽  
Author(s):  
R. H. Leuthold ◽  
S. Badertscher ◽  
H. Imboden
Keyword(s):  
Fungus Comb

scholarly journals Enzyme Activities at Different Stages of Plant Biomass Decomposition in Three Species of Fungus-Growing Termites

2017 ◽  
Vol 84 (5) ◽  
Author(s):  
Rafael R. da Costa ◽  
Haofu Hu ◽  
Bo Pilgaard ◽  
Sabine M. E. Vreeburg ◽  
Julia Schückel ◽  
...  
Keyword(s):  
Plant Material ◽  
Plant Biomass ◽  
Fungal Spores ◽  
Decomposition Process ◽  
Old World ◽  
Content Type ◽  
Substrate Conversion ◽  
Fungus Comb ◽  
Dead Plant ◽  
Plant Polymer

ABSTRACTFungus-growing termites rely on mutualistic fungi of the genusTermitomycesand gut microbes for plant biomass degradation. Due to a certain degree of symbiont complementarity, this tripartite symbiosis has evolved as a complex bioreactor, enabling decomposition of nearly any plant polymer, likely contributing to the success of the termites as one of the main plant decomposers in the Old World. In this study, we evaluated which plant polymers are decomposed and which enzymes are active during the decomposition process in two major genera of fungus-growing termites. We found a diversity of active enzymes at different stages of decomposition and a consistent decrease in plant components during the decomposition process. Furthermore, our findings are consistent with the hypothesis that termites transport enzymes from the older mature parts of the fungus comb through young worker guts to freshly inoculated plant substrate. However, preliminary fungal RNA sequencing (RNA-seq) analyses suggest that this likely transport is supplemented with enzymes producedin situ. Our findings support that the maintenance of an external fungus comb, inoculated with an optimal mixture of plant material, fungal spores, and enzymes, is likely the key to the extraordinarily efficient plant decomposition in fungus-growing termites.IMPORTANCEFungus-growing termites have a substantial ecological footprint in the Old World (sub)tropics due to their ability to decompose dead plant material. Through the establishment of an elaborate plant biomass inoculation strategy and through fungal and bacterial enzyme contributions, this farming symbiosis has become an efficient and versatile aerobic bioreactor for plant substrate conversion. Since little is known about what enzymes are expressed and where they are active at different stages of the decomposition process, we used enzyme assays, transcriptomics, and plant content measurements to shed light on how this decomposition of plant substrate is so effectively accomplished.

scholarly journals Caste-specific nutritional differences define carbon and nitrogen fluxes within symbiotic food webs in African termite mounds

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Risto Vesala ◽  
Laura Arppe ◽  
Jouko Rikkinen
Keyword(s):  
Stable Isotopes ◽  
General Mechanism ◽  
Food Chains ◽  
Fungal Mycelium ◽  
Termite Mounds ◽  
Carbon And Nitrogen ◽  
Plant Matter ◽  
Stable Isotope Signatures ◽  
Fungus Comb ◽  
Symbiotic Fungi

Abstract Fungus-growing termites of the genus Macrotermes cultivate symbiotic fungi (Termitomyces) in their underground nest chambers to degrade plant matter collected from the environment. Although the general mechanism of food processing is relatively well-known, it has remained unclear whether the termites get their nutrition primarily from the fungal mycelium or from plant tissues partly decomposed by the fungus. To elucidate the flows of carbon and nitrogen in the complicated food-chains within the nests of fungus-growing termites, we determined the stable isotope signatures of different materials sampled from four Macrotermes colonies in southern Kenya. Stable isotopes of carbon revealed that the termite queen and the young larvae are largely sustained by the fungal mycelium. Conversely, all adult workers and soldiers seem to feed predominantly on plant and/or fungus comb material, demonstrating that the fungal symbiont plays a different nutritional role for different termite castes. Nitrogen stable isotopes indicated additional differences between castes and revealed intriguing patterns in colony nitrogen cycling. Nitrogen is effectively recycled within the colonies, but also a presently unspecified nitrogen source, most likely symbiotic nitrogen-fixing bacteria, seems to contribute to nitrogen supply. Our results indicate that the gut microbiota of the termite queen might be largely responsible for the proposed nitrogen fixation.

Production of metabolic gases by nests of the termite Macrotermes jeanneli in Kenya

1997 ◽  
Vol 13 (4) ◽  
pp. 491-510 ◽  
Author(s):  
J. P. E. C. Darlington ◽  
P. R. Zimmerman ◽  
J. Greenberg ◽  
C. Westberg ◽  
P. Bakwin
Keyword(s):  
Carbon Dioxide ◽  
Water Loss ◽  
Population Data ◽  
Gas Production ◽  
Nest Size ◽  
Tree Roots ◽  
Excess Carbon ◽  
Fungus Combs ◽  
Direct Observations ◽  
Fungus Comb

ABSTRACTNests of a fungus-growing termite Macrotermes jeanneli discharge all their metabolic gases through a single outlet to the atmosphere. This made it possible to measure the production of metabolic gases, and the rates of water loss, for intact nests in the field. Rates of production of carbon dioxide and methane from isolated nest components (different termite castes and intact fungus combs) were measured. Using previously published nest population data and fungus comb weights in relation to nest size, the expected gas production rates for intact nests were calculated. These estimates were compared with direct observations of the gaseous outflow from intact nests. The rates were in reasonable agreement, but some nests emitted excess carbon dioxide, probably produced by respiration of tree roots and non-termite soil organisms. Large nests may have a total gas outflow of 100,000 to 400,000 1 d–1 including 800 to 1500 1 d–1 of CO2 and 0.5 to 1.3 1 d–1 of CH4. Nests lose water at the rate of up, to 13 1 d–1 gross, but allowing for ambient humidity the net water loss was up to about 5 1 d–1. Some of this is metabolic water, but the larger proportion comes from the soil. Area-based estimates of gas production were made for this and two other species of Macrotermes, but they are not accurate because the field distribution and mound density are not adequately known.

scholarly journals Symbiotic Fungi Produce Laccases Potentially Involved in Phenol Degradation in Fungus Combs of Fungus-Growing Termites in Thailand

2005 ◽  
Vol 71 (12) ◽  
pp. 7696-7704 ◽  
Author(s):  
Yaovapa Taprab ◽  
Toru Johjima ◽  
Yoshimasa Maeda ◽  
Shigeharu Moriya ◽  
Savitr Trakulnaleamsai ◽  
...  
Keyword(s):  
Gene Product ◽  
Laccase Activity ◽  
Phenol Degradation ◽  
Plant Litter ◽  
Partial Purification ◽  
Copper Binding ◽  
Degenerate Primers ◽  
Fungus Combs ◽  
Fungus Comb ◽  
Symbiotic Fungi

ABSTRACT Fungus-growing termites efficiently decompose plant litter through their symbiotic relationship with basidiomycete fungi of the genus Termitomyces. Here, we investigated phenol-oxidizing enzymes in symbiotic fungi and fungus combs (a substrate used to cultivate symbiotic fungi) from termites belonging to the genera Macrotermes, Odontotermes, and Microtermes in Thailand, because these enzymes are potentially involved in the degradation of phenolic compounds during fungus comb aging. Laccase activity was detected in all the fungus combs examined as well as in the culture supernatants of isolated symbiotic fungi. Conversely, no peroxidase activity was detected in any of the fungus combs or the symbiotic fungal cultures. The laccase cDNA fragments were amplified directly from RNA extracted from fungus combs of five termite species and a fungal isolate using degenerate primers targeting conserved copper binding domains of basidiomycete laccases, resulting in a total of 13 putative laccase cDNA sequences being identified. The full-length sequences of the laccase cDNA and the corresponding gene, lcc1-2, were identified from the fungus comb of Macrotermes gilvus and a Termitomyces strain isolated from the same fungus comb, respectively. Partial purification of laccase from the fungus comb showed that the lcc1-2 gene product was a dominant laccase in the fungus comb. These findings indicate that the symbiotic fungus secretes laccase to the fungus comb. In addition to laccase, we report novel genes that showed a significant similarity with fungal laccases, but the gene product lacked laccase activity. Interestingly, these genes were highly expressed in symbiotic fungi of all the termite hosts examined.

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