The channels are thought to have structural similarity to ␣-subunits of voltage-gated K ϩ channels, with intracellular amino and carboxy termini and four proteins required for coordination of a single ion pore. As with K ϩ channels, heteromultimerization confers greater diversity. However, unlike voltage-gated K ϩ channels, membrane depolarization is not the primary trigger for channel activity. Instead, chemical factors are considered to be primary stimuli. Details of the chemical sensing properties are becoming apparent and hold promise for revealing further complexity and novelty. In addition, important roles of TRP channels have emerged, including in sensation and cell survival, but we are far from a full appreciation of the purposes of these channels and, in some cases, there is relatively little understanding of TRP family members -one example being TRPM3.

No abstract

The fiber in corn kernels, currently unutilized in the corn to ethanol process, represents an opportunity for introduction of cellulose conversion technology. We report here that Clostridium thermocellum can solubilize over 90% of the carbohydrate in autoclaved corn fiber, including its hemicellulose component glucuronoarabinoxylan (GAX). However, Thermoanaerobacterium thermosaccharolyticum or several other described hemicellulose-fermenting thermophilic bacteria can only partially utilize this GAX. We describe the isolation of a previously undescribed organism, Herbinix spp. strain LL1355, from a thermophilic microbiome that can consume 85% of the recalcitrant GAX. We sequence its genome, and based on structural analysis of the GAX, identify six enzymes that hydrolyze GAX linkages. Combinations of up to four enzymes are successfully expressed in T. thermosaccharolyticum. Supplementation with these enzymes allows T. thermosaccharolyticum to consume 78% of the GAX compared to 53% by the parent strain and increases ethanol yield from corn fiber by 24%.