ABSTRACT
Recombinant DNA technologies enable the direct isolation and expression of novel genes from biotopes containing complex consortia of uncultured microorganisms. In this study, genomic libraries were constructed from microbial DNA isolated from insect intestinal tracts from the orders Isoptera (termites) and Lepidoptera (moths). Using a targeted functional assay, these environmental DNA libraries were screened for genes that encode proteins with xylanase activity. Several novel xylanase enzymes with unusual primary sequences and novel domains of unknown function were discovered. Phylogenetic analysis demonstrated remarkable distance between the sequences of these enzymes and other known xylanases. Biochemical analysis confirmed that these enzymes are true xylanases, which catalyze the hydrolysis of a variety of substituted beta-1,4-linked xylose oligomeric and polymeric substrates and produce unique hydrolysis products. From detailed polyacrylamide carbohydrate electrophoresis analysis of substrate cleavage patterns, the xylan polymer binding sites of these enzymes are proposed.
Subject(s)
Bacteria/enzymology , Digestive System/microbiology , Endo-1,4-beta Xylanases/genetics , Endo-1,4-beta Xylanases/metabolism , Fungi/enzymology , Isoptera/microbiology , Moths/microbiology , Amino Acid Sequence , Animals , Bacteria/genetics , DNA, Bacterial/analysis , DNA, Bacterial/isolation & purification , DNA, Fungal/analysis , DNA, Fungal/isolation & purification , Endo-1,4-beta Xylanases/chemistry , Endo-1,4-beta Xylanases/classification , Fungi/genetics , Gene Library , Molecular Sequence Data , Phylogeny , Sequence AlignmentABSTRACT
This study explored whether a meridian-based procedure, Emotional Freedom Techniques (EFT), can reduce specific phobias of small animals under laboratory-controlled conditions. Randomly assigned participants were treated individually for 30 min with EFT (n = 18) or a comparison condition, diaphragmatic breathing (DB) (n = 17). ANOVAS revealed that EFT produced significantly greater improvement than did DB behaviorally and on three self-report measures, but not on pulse rate. The greater improvement for EFT was maintained, and possibly enhanced, at six- to nine-months follow-up on the behavioral measure. These findings suggest that a single treatment session using EFT to reduce specific phobias can produce valid behavioral and subjective effects. Some limitations of the study also are noted and clarifying research suggested.
