The metabolome of the model species Chlamydomonas reinhardtii has been analyzed during 120 h of sulfur depletion to induce anaerobic hydrogen (H(2)) production, using NMR spectroscopy, gas chromatography coupled to mass spectrometry, and TLC. The results indicate that these unicellular green algae consume freshly supplied acetate in the medium to accumulate energy reserves during the first 24 h of sulfur depletion. In addition to the previously reported accumulation of starch, large amounts of triacylglycerides were deposited in the cells. During the early 24- to 72-h time period fermentative energy metabolism lowered the pH, H(2) was produced, and amino acid levels generally increased. In the final phase from 72 to 120 h, metabolism slowed down leading to a stabilization of pH, even though some starch and most triacylglycerides remained. We conclude that H(2) production does not slow down due to depletion of energy reserves but rather due to loss of essential functions resulting from sulfur depletion or due to a build-up of the toxic fermentative products formate and ethanol.

With SGF Profiling™ we introduce an NMR-based screening method for the quality control of fruit juices. This method has been developed in a joint effort by Bruker BioSpin GmbH and SGF International e.V. The system is fully automated with respect to sample transfer, measurement, data analysis and reporting and is set up on an Avance 400 MHz flow-injection NMR spectrometer. For each fruit juice a multitude of parameters related to quality and authenticity are evaluated simultaneously from a single data set acquired within a few minutes. This multimarker/multi-aspect NMR screening approach features low cost-per-sample and is highly competitive with conventional and targeted fruit juice quality control methods.

The three-dimensional structure of the type 1 inositol 1,4,5-trisphosphate receptor (InsP₃R1) has been determined by electron cryomicroscopy and single-particle reconstruction. The receptor was immunoaffinity-purified and formed functional InsP₃- and heparin-sensitive channels with a unitary conductance similar to native InsP₃Rs. The channel structure exhibits the expected 4-fold symmetry and comprises two morphologically distinct regions: a large pinwheel and a smaller square. The pinwheel region has four radial curved spokes interconnected by a central core. The InsP₃-binding core domain has been localized within each spoke of the pinwheel region by fitting its x-ray structure into our reconstruction. A structural mapping of the amino acid sequences to several functional domains is deduced within the structure of the InsP₃R1 tetramer.

A select set of microalgae are reported to be able to catalyse photobiological H₂ production from water. Based on the model organism Chlamydomonas reinhardtii, a method was developed for the screening of naturally occurring H₂-producing microalgae. By purging algal cultures with N₂ in the dark and subsequent illumination, it is possible to rapidly induce photobiological H₂ evolution. Using NMR spectroscopy for metabolic profiling in C. reinhardtii, acetate, formate, and ethanol were found to be key compounds contributing to metabolic variance during the assay. This procedure can be used to test algal species existing as axenic or mixed cultures for their ability to produce H₂. Using this system, five algal isolates capable of H₂ production were identified in various aquatic systems. A phylogenetic tree was constructed using ribosomal sequence data of green unicellular algae to determine if there were taxonomic patterns of H₂ production. H₂-producing algal species were seen to be dispersed amongst most clades, indicating an H₂-producing capacity preceded evolution of the phylum Chlorophyta.