Biology Faculty Articles

Title

Evolution of glutamine synthetase in heterokonts: evidence for endosymbiotic gene transfer and the early evolution of photosynthesis

Document Type

Article

Publication Date

1-1-2006

Publication Title

Molecular Biology and Evolution

Keywords

secondary endosymbiosis, diatoms, oomycetes, chloroplast, heterokonts

ISSN

0737-4038

Volume

23

Issue/No.

5

First Page

1048

Last Page

1055

Abstract

For most animals, lignocellulose is a nutritionally poor food source that is highly resistant to enteric degradation. Termites, however, have the unique ability to digest lignocellulose with high efficiency, often using it as a sole food source. Another interesting aspect of termite biology is their symbiotic associations with prokaryotic and eukaryotic gut symbionts. Termite symbionts contribute to lignocellulose digestion efficiency, but by no means are they responsible for 100% of lignocellulose digestion in the termite gut. The termite digestome can be defined as the pool of genes, both termite and symbiont, that contribute to lignocellulose depolymerization and digestion, as well as simple sugar fermentation, nutrient transport, and nutrient assimilation. A central goal of termite digestomics research is to define/understand the relative contributions of termite and symbiont gene products to collaborative lignocellulose digestion. While efficient microbial cellulases have already been identified and are presently being used in industrial applications, efficient and inexpensive pre-treatments for lignin and hemicellulose depolymerization are not yet well developed. In this respect, termite digestomics has already offered significant insights, and can continue to identify relevant enzymes, as well as reveal how to optimally combine and utilize these enzymes for maximum synergy. The topics covered in this review are as follows: lignocellulose structure with emphasis on its potential for depolymerization by termite and gut endosymbiont-derived digestive enzymes; termite biology and ecology from the perspectives of termite nutrition, gut physiology, and lignocellulose digestion; and trends identified through recent termite digestomics research. © 2008 Society of Chemical Industry and John Wiley & Sons, Ltd