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1. Wood fibers are a crucial microhabitat for cellulose- and xylan- degrading bacteria in the hindgut of the wood-feeding beetle Odontotaenius disjunctus

   https://doi.org/10.3389/fmicb.2023.1173696  

   Schwarz, Melbert ; Beza-Beza, Cristian F. ; Mikaelyan, Aram ( June 2023 , Frontiers in Microbiology)

   Wood digestion in insects relies on the maintenance of a mosaic of numerous microhabitats, each colonized by distinct microbiomes. Understanding the division of digestive labor between these microhabitats- is central to understanding the physiology and evolution of symbiotic wood digestion. A microhabitat that has emerged to be of direct relevance to the process of lignocellulose digestion is the surface of ingested plant material. Wood particles in the guts of some termites are colonized by a specialized bacterial fiber-digesting microbiome, but whether this represents a widespread strategy among insect lineages that have independently evolved wood-feeding remains an open question.

   In this study, we investigated the bacterial communities specifically associated with wood fibers in the gut of the passalid beetleOdontotaenius disjunctus. We developed a Percoll-based centrifugation method to isolate and enrich the wood particles from the anterior hindgut, allowing us to access the wood fibers and their associated microbiome. We then performed assays of enzyme activity and used short-read and long-read amplicon sequencing of the 16S rRNA gene to identify the composition of the fiber-associated microbiome.

   Our assays demonstrated that the anterior hindgut, which houses a majority of the bacterial load, is an important site for lignocellulose digestion. Wood particles enriched from the anterior hindgut contribute to a large proportion of the total enzyme activity. The sequencing revealed thatO. disjunctus, like termites, harbors a distinct fiber-associated microbiome, but notably, its community is enriched in insect-specific groups ofLactococcusandTuricibacter.

   Our study underscores the importance of microhabitats in fostering the complex symbiotic relationships between wood-feeding insects and their microbiomes. The discovery of distinct fiber-digesting symbionts inO. disjunctus, compared to termites, highlights the diverse evolutionary paths insects have taken to adapt to a challenging diet.

    

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2. Gut microbiomes of sympatric Amazonian wood‐eating catfishes (Loricariidae) reflect host identity and little role in wood digestion

   https://doi.org/10.1002/ece3.6413  

   McCauley, Mark ; German, Donovan P. ; Lujan, Nathan K. ; Jackson, Colin R. ( May 2020 , Ecology and Evolution)

   Neotropical wood‐eating catfishes (family Loricariidae) can occur in diverse assemblages with multiple genera and species feeding on the same woody detritus. As such, they present an intriguing system in which to examine the influence of host species identity on the vertebrate gut microbiome as well as to determine the potential role of gut bacteria in wood digestion. We characterized the gut microbiome of two co‐occurring catfish genera and four species: Panaqolus albomaculatus , Panaqolus gnomus , Panaqolus nocturnus, and Panaque bathyphilus , as well as that of submerged wood on which they feed. The gut bacterial community did not significantly vary across three gut regions (proximal, mid, distal) for any catfish species, although interspecific variation in the gut microbiome was significant, with magnitude of interspecific difference generally reflecting host phylogenetic proximity. Further, the gut microbiome of each species was significantly different to that present on the submerged wood. Inferring the genomic potential of the gut microbiome revealed that the majority of wood digesting pathways were at best equivalent to and more often depleted or nonexistent within the catfish gut compared to the submerged wood, suggesting a minimal role for the gut microbiome in wood digestion. Rather, these fishes are more likely reliant on fiber degradation performed by microbes in the environment, with their gut microbiome determined more by host identity and phylogenetic history. 

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3. Does replacing coal with wood lower CO 2 emissions? Dynamic lifecycle analysis of wood bioenergy

   https://doi.org/10.1088/1748-9326/aaa512  

   Sterman, John D ; Siegel, Lori ; Rooney-Varga, Juliette N ( December 2017 , Environmental Research Letters)
4. The oxygen isotope value of whole wood, α-cellulose, and holocellulose in modern and fossil wood

   https://doi.org/10.1016/j.chemgeo.2023.121405  

   Ren, Junbo ; Schubert, Brian A. ; Lukens, William E. ; Xu, Chenxi ( April 2023 , Chemical Geology)
5. Reply to comment on ‘Does replacing coal with wood lower CO 2 emissions? Dynamic lifecycle analysis of wood bioenergy’

   https://doi.org/10.1088/1748-9326/aaf354  

   Sterman, John D ; Siegel, Lori ; Rooney-Varga, Juliette N ( December 2018 , Environmental Research Letters)