Temporal dynamics of fibrolytic and methanogenic rumen microorganisms during in situ incubation of switchgrass determined by 16S rRNA gene profiling.

The rumen microbial ecosystem is known for its biomass-degrading and methane-producing phenotype. Fermentation of recalcitrant plant material, comprised of a multitude of interwoven fibers, necessitates the synergistic activity of diverse microbial taxonomic groups that inhabit the anaerobic rumen ecosystem. Although interspecies hydrogen (H2) transfer, a process during which bacterially generated H2 is transferred to methanogenic Archaea, has obtained significant attention over the last decades, the temporal variation of the different taxa involved in in situ biomass-degradation, H2 transfer and the methanogenesis process remains to be established.

Cellulosic biomass pretreatment and sugar yields as a function of biomass particle size.

Three lignocellulosic pretreatment techniques (ammonia fiber expansion, dilute acid and ionic liquid) are compared with respect to saccharification efficiency, particle size and biomass composition. In particular, the effects of switchgrass particle size (32-200) on each pretreatment regime are examined. Physical properties of untreated and pretreated samples are characterized using crystallinity, surface accessibility measurements and scanning electron microscopy (SEM) imaging.

Exploring the role of CheA3 in Desulfovibrio vulgaris Hildenborough motility.

Sulfate-reducing bacteria such as Desulfovibrio vulgaris Hildenborough are often found in environments with limiting growth nutrients. Using lactate as the electron donor and carbon source, and sulfate as the electron acceptor, wild type D. vulgaris shows motility on soft agar plates.

Isolation and proteomic characterization of the Arabidopsis Golgi defines functional and novel components involved in plant cell wall biosynthesis.

The plant Golgi plays a pivotal role in the biosynthesis of cell wall matrix polysaccharides, protein glycosylation, and vesicle trafficking. Golgi-localized proteins have become prospective targets for reengineering cell wall biosynthetic pathways for the efficient production of biofuels from plant cell walls. However, proteomic characterization of the Golgi has so far been limited, owing to the technical challenges inherent in Golgi purification.

Correlative microscopy for phylogenetic and ultrastructural characterization of microbial communities.

Transmission electron microscopy (TEM) can provide ultrastructural information for cells in microbial community samples and phylogenetic information can be recovered via molecular surveys. Here we report an approach to link these data sets by coupling fluorescence in situ hybridization (FISH) with either conventional biological or cryogenic TEM. The method could fundamentally improve our understanding of the organization and functioning of microbial communities in natural systems.

The cooperative activities of CSLD2, CSLD3, and CSLD5 are required for normal Arabidopsis development.

Glycosyltransferases of the Cellulose Synthase Like D (CSLD) subfamily have been reported to be involved in tip growth and stem development in Arabidopsis. The csld2 and csld3 mutants are root hair defective and the csld5 mutant has reduced stem growth. In this study, we produced double and triple knockout mutants of CSLD2, CSLD3, and CSLD5.

High-throughput enzymatic hydrolysis of lignocellulosic biomass via in-situ regeneration.

The high cost of lignocellulolytic enzymes is one of the main barriers towards the development of economically competitive biorefineries. Enzyme engineering can be used to significantly increase the production rate as well as specific activity of enzymes. However, the success of enzyme optimization efforts is currently limited by a lack of robust high-throughput (HTP) cellulase screening platforms for insoluble pretreated lignocellulosic substrates.

Comparison of dilute acid and ionic liquid pretreatment of switchgrass: Biomass recalcitrance, delignification and enzymatic saccharification.

The efficiency of two biomass pretreatment technologies, dilute acid hydrolysis and dissolution in an ionic liquid, are compared in terms of delignification, saccharification efficiency and saccharide yields with switchgrass serving as a model bioenergy crop. When subject to ionic liquid pretreatment (dissolution and precipitation of cellulose by anti-solvent) switchgrass exhibited reduced cellulose crystallinity, increased surface area, and decreased lignin content compared to dilute acid pretreatment. Pretreated material was characterized by powder X-ray diffraction, scanning electron microscopy, Fourier transform infrared spectroscopy, Raman spectroscopy and chemistry methods.

Sequence of late molecular events in the activation of rhodopsin.

Activation of the G protein-coupled receptor rhodopsin involves both the motion of transmembrane helix 6 (TM6) and proton exchange events. To study how these activation steps relate to each other, spin-labeled rhodopsin in solutions of dodecyl maltoside was used so that time-resolved TM6 motion and proton exchange could each be monitored as a function of pH and temperature after an activating light flash. The results reveal that the motion of TM6 is not synchronized with deprotonation of the Schiff base that binds the chromophore to the protein but is an order of magnitude slower at 30 degrees C.

Rhodopsin and 9-demethyl-retinal analog: effect of a partial agonist on displacement of transmembrane helix 6 in class A G protein-coupled receptors.

Rhodopsin is the visual pigment of rod cells and a prototypical G protein-coupled receptor. It is activated by cis-->trans photoisomerization of the covalently bound chromophore 11-cis-retinal, which acts in the cis configuration as an inverse agonist. Light-induced formation of the full agonist all-trans-retinal in situ triggers conformational changes in the protein moiety.