Theses and Dissertations
Issuing Body
Mississippi State University
Advisor
Shmulsky, Rubin
Committee Member
Stokes, C. Elizabeth
Committee Member
Peterson, Daniel G.
Committee Member
Nikolic, Dragica Jeremic
Committee Member
Tang, Juliet D.
Date of Degree
5-3-2019
Original embargo terms
Worldwide
Document Type
Dissertation - Open Access
Major
Sustainable Bioproducts
Degree Name
Doctor of Philosophy
College
College of Forest Resources
Department
Department of Sustainable Bioproducts
Abstract
The overall aim of this study was to investigate the potential influence of chitosan, a biodegradable and antimicrobial compound, on termite hindgut symbionts. For this purpose, a morphological quantifying technique was conducted on the protist community’s hindgut after feeding termites on chitosan-treated wood. The aim was to characterize the diversity of protist species in the economically important dark southern subterranean termite, Reticulitermes virginicus. A molecular phylogenetic analysis of the V3 and V4 hyper-variable regions of 16S ribosomal RNA (rRNA) gene of the bacterial community in the hindgut of R. virginicus was performed on termites exposed to chitosan treatment. Light microscopy visualization of protist species residing in the hindgut of workers showed presence of ten protist species both in the control sample and in termites fed a low concentration of chitosan. In this study, the coexistence of two species of the genus Trichonympha (T. agilis and T. burlesquei) is reported for the first time in R. virginicus. Monocercomonas sp. and Trichomitus trypanoides were the only two protists found in termites exposed to wood treated with higher chitosan concentration solutions and the absence of wood fragments in their food vacuoles was clear. This feature indicates that these two protists may not be involved in the digestion of the wood fragments impregnated with chitosan. The results of this study indicated that the potential effect of chitosan caused elimination of the protist species in termite hindguts. The genomic DNA of bacterial hindgut community of R. virginicus were profiled using sequences which amplified theV3-V4 sub-regions of 16S rRNA gene. Sequences were analyzed using a taxonomic analysis tool, Quantitative Insights Into Microbial Ecology (OIIME 2), in order to infer the effect of chitosan on the composition of the bacterial fauna in the hindgut. The richness and evenness results indicated that the most diversity was observed in the bacteria from termites not being exposed (UNX) to treatment compared to other treatment groups. On the other hand, the lowest richness and evenness were determined for chitosan-treated wood (CTE) and starved termites (STV). Of 28 bacterial phyla, Bacteroidetes, Firmicutes, Elusimicrobia, and Proteobacteria were the most dominant phyla across all the treatment groups. The results suggest that chitosan treated wood led to the microbial community shifts in R. virginicus. In addition, lack of a nutrition source and other changes in termite’s food affect the termite hindgut bacterial diversity.
URI
https://hdl.handle.net/11668/21243
Recommended Citation
Telmadarrehei, Telmah, "Study of Subterranean Termite Gut Symbionts as Affected by Chitosan Treatment of Wood" (2019). Theses and Dissertations. 4133.
https://scholarsjunction.msstate.edu/td/4133
Comments
chitosan||Reticulitermes virginicus||protist diversity||hindgut bacteria||16S rRNA gene||Illumina amplicon sequencing