Enantioselective separation of all-E-astaxanthin and its determination in microbial sources.

A method for the enantioselective separation of all-E-astaxanthin (3,3'-dihydroxy-beta,beta-carotene-4,4'-dione), an important colorant in the feed industry, was developed. Different chiral stationary phases (CSPs) such as Pirkle phases (R,R Ulmo and l-leucine), modified polysaccharides and a beta-cyclodextrin have been investigated on their separation performance of astaxanthin enantiomers. Direct resolution was only achieved employing the Chiralcel OD-RH (cellulose-tris-3,5-dimethylphenyl-carbamate) under reversed phase conditions.

Species-specific Cd-stress response in the white rot basidiomycetes Abortiporus biennis and Cerrena unicolor.

The effect of cadmium (Cd) on fungal growth, Cd bioaccumulation and biosorption, and on the formation of potential heavy metal response indicators such as thiols, oxalate, and laccase was investigated in the white rot fungi Cerrena unicolor andAbortiporus biennis. Only the highest Cd concentration employed (200 microM) inhibited growth of C. unicolor, whereas already lower Cd concentrations caused decreasing mycelia dry weights in A.

Cadmium induces a novel metallothionein and phytochelatin 2 in an aquatic fungus.

Cadmium stress response was measured at the thiol peptide level in an aquatic hyphomycete (Heliscus lugdunensis). In liquid culture, 0.1 mM cadmium increased the glutathione (GSH) content and induced the synthesis of additional thiol peptides.

Quantification of metallothionein-like proteins in the mussel Mytilus galloprovincialis using RP-HPLC fluorescence detection.

A HPLC-fluorescence method, using the fluorophore SBD-F (ammonium-7-fluorobenz-2-oxa-1,3-diazole-4-sulfonate), was adapted for the quantification of metallothioneins and their isoforms from the Moroccan mussel Mytilus galloprovincialis. The method was first optimized using a rabbit liver metallothionein. The effects of EDTA, tris(2-carboxyethyl)phosphine, and SBD-F on the labeling efficiency were studied.

Coumarins give misleading absorbance with Ellman's reagent suggestive of thiol conjugates.

In the course of a screening for phytochelatins in cadmium-exposed bryophytes in the terrestrial mosses Polytrichum formosum and Atrichum undulatum we detected compounds with absorption properties and retention times similar to phytochelatins when applying the commonly used standard method RP-HPLC and post-column derivatization with thiol-specific DTNB (Ellman) reagent. Moreover, as with phytochelatins known in other plants, the concentrations of these compounds increased slightly after Cd stress. The concentration of the precursor glutathione (gamma-ECG), however, increased in the presence of Cd.