Why is it so difficult to construct Q(i) site mutants in Chlamydomonas reinhardtii?

The cytochrome b(6)f complex catalyses electron transfer from plastoquinol to a hydrosoluble acceptor (plastocyanin), while building up an electrochemical proton gradient. Oxidation and reduction of plastoquinol occur respectively at the Q(o) site (exposed on the luminal side of the thylakoid membrane) and at the Q(i) site (facing the stroma). The discovery of an additional c'-type heme in the Q(i) site has cast a new light on the difficulties previously encountered to obtain mutants at this site.

Production and certification of four frozen human serum certified reference materials containing creatinine and electrolytes.

Background: This paper describes the preparation, analysis and certification of four frozen human serum certified reference materials (CRMs) containing creatinine and the electrolytes calcium, lithium, magnesium, potassium and sodium. These materials have been prepared to give concentrations of these analytes that cover the currently accepted analytical range.

Methods: The analysis of the materials for certification purposes has been carried out using methodology traceable to primary standards, and which is acceptable as a reference method.

Multiple and simultaneous fluorophore detection using fluorescence spectrometry and partial least-squares regression with sample-specific confidence intervals.

Fluorescent labeling is widely used in biological and chemical analysis, and the drive for increased throughput is stretching multiplexing capabilities to the limit. The limiting factor in multiplexed analyses is the ability to subsequently deconvolute the signals. Consequently, alternative approaches for interpreting complex data sets are required to allow individual components to be identified.

SERRS as a more sensitive technique for the detection of labelled oligonucleotides compared to fluorescence.

This communication contains data from a comparison between the detection limits obtained using surface enhanced resonance Raman scattering (SERRS) and fluorescence detection of dye labelled oligonucleotides. The results show that the detection limits for SERRS are generally at least three orders of magnitude lower than those obtained for fluorescence.

Rapid, noninvasive screening for perturbations of metabolism and plant growth using chlorophyll fluorescence imaging.

A rapid, noninvasive technique involving imaging of chlorophyll fluorescence parameters for detecting perturbations of leaf metabolism and growth in seedlings is described. Arabidopsis seedlings were grown in 96-well microtitre plates for 4 d and then treated with eight herbicides with differing modes of action to induce perturbations in a range of different metabolic processes. Imaging of chlorophyll fluorescence emissions from 96 seedlings growing on a microtitre plate enabled images of a number of fluorescence parameters to be rapidly and simultaneously produced for the plants in each well.