Tropinone reductases (TRs) are essential enzymes in the tropane alkaloid biosynthesis, providing either tropine for hyoscyamine and scopolamine formation or providing pseudotropine for calystegines. Two cDNAs coding for TRs were isolated from potato (Solanum tuberosum L.) tuber sprouts and expressed in E. coli. One reductase formed pseudotropine, the other formed tropine and showed kinetic properties typical for tropine-forming tropinone reductases (TRI) involved in hyoscyamine formation. Hyoscyamine and tropine are not found in S. tuberosum plants. Potatoes contain calystegines as the only products of the tropane alkaloid pathway. Polyclonal antibodies raised against both enzymes were purified to exclude cross reactions and were used for Western-blot analysis and immunolocalisation. The TRI (EC 1.1.1.206) was detected in protein extracts of tuber tissues, but mostly in levels too low to be localised in individual cells. The function of this enzyme in potato that does not form hyoscyamine is not clear. The pseudotropine-forming tropinone reductase (EC 1.1.1.236) was detected in potato roots, stolons, and tuber sprouts. Cortex cells of root and stolon contained the protein; additional strong immuno-labelling was located in phloem parenchyma. In tuber spouts, however, the protein was detected in companion cells.

Recent studies have shown that cyclin-dependent kinase (CDK) inhibitors can have a tremendous impact on cell cycle progression in plants. In animals, CDK inhibitors are tightly regulated, especially by posttranslational mechanisms of which control of nuclear access and regulation of protein turnover are particularly important. Here we address the posttranslational regulation of INHIBITOR/INTERACTOR OF CDK 1 (ICK1)/KIP RELATED PROTEIN 1 (KRP1), an Arabidopsis (Arabidopsis thaliana) CDK inhibitor. We show that ICK1/KRP1 exerts its function in the nucleus and its presence in the nucleus is controlled by multiple nuclear localization signals as well as by nuclear export. In addition, we show that ICK1/KRP1 localizes to different subnuclear domains, i.e. in the nucleoplasm and to the chromocenters, hinting at specific actions within the nuclear compartment. Localization to the chromocenters is mediated by an N-terminal domain, in addition we find that this domain may be involved in cyclin binding. Further we demonstrate that ICK1/KRP1 is an unstable protein and degraded by the 26S proteasome in the nucleus. This degradation is mediated by at least two domains indicating the presence of at least two different pathways impinging on ICK1/KRP1 protein stability.

Two full-length cDNAs encoding flavonoid-specific glucosyltransferases, UGT73A4 and UGT71F1, were isolated from a cDNA library of Beta vulgaris (Amaranthaceae) cell suspension cultures. They displayed high identity to position-specific betanidin and flavonoid glucosyltransferases from Dorotheanthus bellidiformis (Aizoaceae) and to enzymes with similar substrate specificities from various plant families. The open reading frame of the sequences encode proteins of 476 (UGT73A4) and 492 (UGT71F1) amino acids with calculated molecular masses of 54.07 kDa and 54.39 kDa, and isoelectric points of 5.8 and 5.6, respectively. Both enzymes were functionally expressed in Escherichia coli as His- and GST-tagged proteins, respectively. They exhibited a broad substrate specificity, but a distinct regioselectivity, glucosylating a variety of flavonols, flavones, flavanones, and coumarins. UGT73A4 showed a preference for the 4′- and 7-OH position in the flavonoids, whereas UGT71F1 preferentially glucosylated the 3- or the 7-OH position. Glucosylation of betanidin, the aglycone of the major betacyanin, betanin, in B. vulgaris was also observed to a low extent by both enzymes. Several O-glycosylated vitexin derivatives isolated from leaves of young B. vulgaris plants and rutin obtained from B. vulgaris tissue culture are discussed as potential endogenous products of UGT73A4 and UGT71F1. The results are analyzed with regard to evolution and specificity of plant natural product glucosyltransferases.

The following lichen substances were detected in six species of Physciaceae by HPLC-ESI-MS/MS: Phaeophyscia orbicularis: atranorin (1), methyl ß-orcinolcarboxylate (6), Physcia adscendens: 1, 6, chloroatranorin (2), 5-hydroxyatranorin (3, new), norbaeomycesic acid (4), 3'-demethylatranorin (5, new), Physcia aipolia: 1, 2, 3, 4, 5 and 6, Physcia caesia: 1, 4 and 5, Physcia stellaris: 1, 2, 4, 5 and 6, Physcia tenella: 1, 2, 4, 5 and 6.

Four new antibiotics were isolated from a fermentation broth of Steptomyces lydicus (strain HKI0343). The 13‐membered‐ring peptides (see formula, XY: CH2NH, CHNH; R1, R2: H, OH) are cyclized through a lactone function at serine and also contain the nonproteinogenic amino acid piperazic acid (or a derivative thereof). The peptides show promising activity against various mycobacteria without being cytotoxic.

Vier neue Antibiotika wurden aus Streptomyces lydicus (Stamm HKI0343) isoliert. Die 13‐gliedrigen Peptidringe (siehe Bild; X‐Y=CH2‐NH, CHNH; R1, R2=H, OH) sind über ein Serin zum Lacton cyclisiert und bestehen aus L ‐Alanin, D ‐Leucin, L ‐Serin und der nichtproteinogenen Aminosäure Piperazinsäure oder ihren Derivaten. Die Naturstoffe zeigen eine vielversprechende Wirkung gegen unterschiedliche Mykobakterien, ohne dabei toxisch zu sein.

Tocopherols and tocotrienols are vitamin E compounds, differing only in the saturation state of the isoprenoid side chain. Tocopherol biosynthesis, physiology and distribution have been studied in detail. Tocopherols have been found in many different plant species, and plant tissues. In contrast, comparatively little is known about the physiology and distribution of tocotrienols. These compounds appear to be considerably less widespread in the plant kingdom. In this study 80 different plant species were analysed for the presence of tocotrienols. Twenty-four species were found to contain significant amounts of tocotrienols. No taxonomic relation was apparent among the 16 dicotyledonous species that were found to contain tocotrienol. Monocotyledonous species (eight species) belonged either to the Poaceae (six species) or the Aracaceae (two species).A more detailed analysis of tocotrienol accumulation revealed the presence of tocotrienols in several non-photosynthetic tissues and organs, i.e. seeds, fruits and in latex, in concentrations up to 2000 ppm. No tocotrienols could be detected in mature photosynthetic tissues. However, we found the transient accumulation of low levels of tocotrienols in the young coleoptiles of plant species whose seeds contained tocotrienols. No measurable tocotrienol biosynthesis was apparent in coleoptiles, or in chloroplasts isolated from such coleoptiles. In line with these results, we found that tocotrienol accumulation in coleoptiles was not associated with chloroplasts. Based on our data, we conclude that tocotrienols may be transiently present in photosynthetically active tissues, however, it remains to be proven whether the tocotrienols are biosynthesised in such tissues, or imported from elsewhere in the plant.

Tocopherols and tocotrienols are present in mature seeds. Yet, little is known about the physiological role and the metabolism of these compounds during seed development. Here we present data on tocopherol and tocotrienol accumulation during seed development in Vitis vinifera L. cv. Albert Lavallée (Royal). This species was chosen for its ability to synthesize both tocopherols and tocotrienols. It is shown here for the first time that during seed development there are significant differences in localization and accumulation kinetics of tocopherols and tocotrienols. Tocopherols are found homogeneously dispersed throughout all tissues of the seed, in concentrations ranging from 20 to 100 μg tocopherol per g dry weight. Tocopherol levels decrease gradually during seed development. In contrast, tocotrienols are only found in the endosperm of the seeds, accumulating in a sigmoid fashion during the maturation period of seed development. Tocotrienol levels were found to be (54 ± 7.4) μg/g dry seed in 90-day-old seeds of V. vinifera L. Furthermore, tocotrienol biosynthesis is demonstrated in these seeds during tocotrienol accumulation and in an endosperm fraction isolated at 75 days after flowering.

Ten years after the establishment of the term proteome, the science surrounding it has yet to fulfill its potential. While a host of technologies have generated lists of protein names, there are only a few reported studies that have examined the individual proteins at the covalent chemical level defined as protein species in 1997 and their function. In the current study, we demonstrate that this is possible with two-dimensional gel electrophoresis (2-DE) and mass spectrometry by presenting clear evidence of in vivo N-terminal alpha A crystallin truncation and relating this newly detected protein species to alpha crystallin activity regulation by protease cleavage in the healthy young murine lens. We assess the present state of technology and suggest a shift in resources and paradigm for the routine attainment of the protein species level in proteomics.

The eye lens is a fascinating organ as it is in essence living transparent matter. Lenticular transparency is achieved through the peculiarities of lens morphology, a semi-apoptotic process where cells elongate and loose their organelles and the precise molecular arrangement of the bulk of soluble lenticular proteins, the crystallins. The 16 crystallins ubiquitous in mammals and their modifications have been extensively characterized by 2-DE, liquid chromatography, mass spectrometry and other protein analysis techniques. The various solubility dependant fractions as well as subproteomes of lenticular morphological sections have also been explored in detail. Extensive post translational modification of the crystallins is encountered throughout the lens as a result of ageing and disease resulting in a vast number of protein species. Proteomics methodology is therefore ideal to further comprehensive understanding of this organ and the factors involved in cataractogenesis.