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Transformation of tea catechins and flavonoid glycosides by treatment with Japanese post-fermented tea acetone powder

Japanese post-fermented teas are produced by a combination of aerobic and anaerobic microbial fermentation of the leaves of tea plant. Recently, it was revealed that tea products contain characteristic polyphenols identical to the tea catechin metabolites produced by mammalian intestinal bacteria, such as (2S)-1-(3′,4′,5′-trihydroxyphenyl)-3-(2″,4″,6″-trihydroxyphenyl)-propan-2-ol (EGC-M1). In the present study, degradation of epigallocatechin-3-O-gallate (EGCg) and epigallocatechin (EGC) with acetone powder prepared from Japanese post-fermented tea was examined. Under aerobic conditions, EGCg was hydrolysed to EGC and gallic acid, which were further converted to gallocatechin (GC) and pyrogallol, respectively. Under anaerobic conditions, EGCg was hydrolysed to EGC, which was further metabolised to GC, EGC-M1 and (4R)-5-(3,4,5-trihydroxyphenyl)-4-hydroxypentanoic acid (EGC-M2). Gallic acid was degraded to pyrogallol and then further decomposed. Anaerobic treatment of EGC with the acetone powder yielded EGC-M1, EGC-M2, (4R)-5-(3,4,5-trihydroxyphenyl)-γ-valerolactone, and (4R)-5-(3,4 -dihydroxyphenyl)-γ-valerolactone. Furthermore, similar anaerobic treatment of rutin and hesperidin yielded 3,4-dihydroxyphenylacetic acid and 3-(3,4-dihydroxyphenyl)propanoic acid, respectively

The roles of the sole activator-type auxin response factor in pattern formation of marchantia polymorpha

Cell division patterning is important to determine body shape in plants. Nuclear auxin signaling mediated by AUXIN RESPONSE FACTOR (ARF) transcription factors affects plant growth and development through regulation of cell division, elongation and differentiation. The evolutionary origin of the ARF-mediated pathway dates back to at least the common ancestor of bryophytes and other land plants. The liverwort Marchantia polymorpha has three phylogenetically distinct ARFs: MpARF1, the sole ‘activator’ ARF; and MpARF2 and MpARF3, two ‘repressor’ ARFs. Genetic screens for auxin-resistant mutants revealed that loss of MpARF1 function conferred auxin insensitivity. Mparf1 mutants showed reduced auxin-inducible gene expression and various developmental defects, including thallus twisting and gemma malformation. We further investigated the role of MpARF1 in gemma development, which is traceable at the cellular level. In wild-type plants, a gemma initial first undergoes several transverse divisions to generate a single-celled stalk and a gemma proper, followed by rather synchronous longitudinal divisions in the latter. Mparf1 mutants often contained multicelled stalks and showed defects in the execution and timing of the longitudinal divisions. While wild-type gemmae finally generate two meristem notches, Mparf1 gemmae displayed various numbers of ectopic meristems. These results suggest that MpARF1 regulates formative cell divisions and axis formation through auxin responses. The mechanism for activator ARF regulation of pattern formation may be shared in land plants and therefore important for the general acquisition of three-dimensional body plans

Auxin-mediated transcriptional system with a minimal set of components is critical for morphogenesis through the life cycle in Marchantia polymorpha

The plant hormone auxin regulates many aspects of plant growth and development. Recent progress in Arabidopsis provided a scheme that auxin receptors, TIR1/AFBs, target transcriptional co-repressors, AUX/IAAs, for degradation, allowing ARFs to regulate transcription of auxin responsive genes. The mechanism of auxin-mediated transcriptional regulation is considered to have evolved around the time plants adapted to land. However, little is known about the role of auxin-mediated transcription in basal land plant lineages. We focused on the liverwort Marchantia polymorpha, which belongs to the earliest diverging lineage of land plants. M. polymorpha has only a single TIR1/AFB (MpTIR1), a single AUX/IAA (MpIAA), and three ARFs (MpARF1, MpARF2, and MpARF3) in the genome. Expression of a dominant allele of MpIAA with mutations in its putative degron sequence conferred an auxin resistant phenotype and repressed auxin-dependent expression of the auxin response reporter proGH3:GUS. We next established a system for DEX-inducible auxin-response repression by expressing the putatively stabilized MpIAA protein fused with the glucocorticoid receptor domain (MpIAA(mDII)-GR). Repression of auxin responses in (pro)MpIAA:MpIAA(mDII)-GR plants caused severe defects in various developmental processes, including gemmaling development, dorsiventrality, organogenesis, and tropic responses. Transient transactivation assays showed that the three MpARFs had different transcriptional activities, each corresponding to their phylogenetic classifications. Moreover, MpIAA and MpARF proteins interacted with each other with different affinities. This study provides evidence that pleiotropic auxin responses can be achieved by a minimal set of auxin signaling factors and suggests that the transcriptional regulation mediated by TIR1/AFB, AUX/IAA, and three types of ARFs might have been a key invention to establish body plans of land plants. We propose that M. polymorpha is a good model to investigate the principles and the evolution of auxin-mediated transcriptional regulation and its roles in land plant morphogenesis

BEN3/BIG2 ARF GEF is involved in brefeldin a-sensitive trafficking at the trans-golgi network/early endosome in arabidopsis thaliana

Membrane traffic at the trans-Golgi network (TGN) is crucial for correctly distributing various membrane proteins to their destination. Polarly localized auxin efflux proteins, including PIN-FORMED1 (PIN1), are dynamically transported between the endosomes and the plasma membrane (PM) in the plant cells. The intracellular trafficking of PIN1 protein is sensitive to the fungal toxin brefeldin A (BFA), which is known to inhibit guanine nucleotide exchange factors for ADP ribosylation factors (ARF GEFs) such as GNOM. However, the molecular details of the BFA-sensitive trafficking pathway have not been fully revealed. In a previous study, we identified an Arabidopsis mutant BFA-visualized endocytic trafficking defective 3 (ben3) which exhibited reduced sensitivity to BFA in terms of BFA-induced intracellular PIN1 agglomeration. Here, we show that BEN3 encodes a member of BIG family ARF GEFs, BIG2. BEN3/BIG2 tagged with fluorescent proteins co-localized with markers for the TGN/early endosome (EE). Inspection of conditionally induced de novo synthesized PIN1 confirmed that its secretion to the PM is BFA sensitive, and established BEN3/BIG2 as a crucial component of this BFA action at the level of the TGN/EE. Furthermore, ben3 mutation alleviated BFAinduced agglomeration of another TGN-localized ARF GEF, BEN1/MIN7. Taken together, our results suggest that BEN3/BIG2 is an ARF GEF component, which confers BFA sensitivity to the TGN/EE in Arabidopsis.</p