Characterization of four esterase genes and esterase activity from the gut of the termite Reticulitermes flavipes.
Four esterase genes and general esterase activity were investigated in the gut of the termite Reticulitermes flavipes. Two genes (RfEst1 and RfEst2) share significant translated identity with a number of insect JH esterases. The two remaining genes (RfEst3 and RfEst4) apparently code for much shorter proteins with similarity to fungal phenolic acid esterases involved in hemicellulose solubilization. All four genes showed consistently high midgut expression. This result was further supported by colorimetric activity assays and Native polyacrylamide gel electrophoresis, which showed significant esterase activity and a number of isoforms in the midgut. The greatest esterase activity and isoform composition were detected when alpha-naphthyl propionate was used as a substrate. Moreover, esterase activity and diverse isoforms were present in gut mitochondrial, microsomal, and cytosolic sub-cellular protein fractions, as well as in the hindgut lumen. These findings reveal an agreement between gut esterase gene expression and activity distributions, and support the idea that R. flavipes gut esterase activity is host (not symbiont)-derived. In addition, these findings support the hypotheses that termite gut esterases may play important roles in lignocellulose digestion and caste differentiation. This study provides important baseline data that will assist ongoing functional-genomic efforts to identify novel genes with roles in semiochemical, hormone, and lignocellulose processing in the termite gut.
Entomology and Nematology Department, University of Florida, Gainesville, FL 32611-0620, USA.
Marsha M
MM
Wheeler
Matthew R
MR
Tarver
Monique R
MR
Coy
Michael E
ME
Scharf
D000595:Amino Acid Sequence; D000818:Animals; D002265:Carboxylic Ester Hydrolases / Q000235:genetics; D004064:Digestive System / Q000201:enzymology*; D004950:Esterases / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D017344:Genes, Insect; D007527:Isoenzymes / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D020049:Isoptera / Q000235:genetics / Q000378:metabolism*; D008031:Lignin / Q000378:metabolism; D008969:Molecular Sequence Data; D009281:Naphthalenes / Q000378:metabolism; D011134:Polysaccharides / Q000378:metabolism; D011422:Propionates / Q000378:metabolism; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D013347:Subcellular Fractions / Q000378:metabolism
D007527:Isoenzymes; D009281:Naphthalenes; D011134:Polysaccharides; D011422:Propionates; C036909:lignocellulose; C060294:1-naphthalenepropionic acid; C007916:hemicellulose; D008031:Lignin; D004950:Esterases; D002265:Carboxylic Ester Hydrolases; C038003:juvenile hormone esterase