Unusual ent-atisane type diterpenoids with 2-oxopropyl skeleton from the roots of Euphorbia ebracteolata and their antiviral activity against human rhinovirus 3 and enterovirus 71

Two novel ent-atisane type diterpenoids possessing the extra unusal 2-oxopropyl moiety (1 and 2) and four known analogues have been isolated from the roots of Euphorbia ebracteolata. The structures and absolute configurations of these compounds were determined by extensive spectroscopic data analysis, including 2D NMR, single-crystal X-ray crystallography, ¹³C NMR calculation, and electronic circular dichroism spectra calculation. Compounds 1 and 2 are the first examples of natural products with ent-atisane type diterpenoids possessing 2-oxopropyl skeleton. Compounds 2, 3, 5, and 6 show antiviral activities against human rhinovirus 3, with IC₅₀ values of 25.27–90.35 μM. Compounds 5 and 6 showed moderate antiviral activities against EV71 at a concentration of 100 μM.     

Identification of 3-deoxy-lyxo-2-heptulosaric acid in the core region of lipopolysaccharides from Rhizobiaceae

A 3-deoxy-2-heptulosaric acid (DHA), very probably with the lyxo-configuration, was identified in the R-core region of lipopolysaccharides from nodulating strains of Rhizobium leguminosarum, Rhizobium meliloti and from all three biovars of the phytopathogenic Agrobacterium tumefaciens. Its structure could be deduced from the fragmentation pattern of the corresponding alditol acetates obtained after reduction of the 2-keto and the 1.7-carboxy groups by sodium borohydride or sodium borodeuteride. DHA in lipopolysaccharide was not destroyed by periodate and is therefore not in a terminal position. Two DHA-containing oligosaccharides, namely glucosyl (1----4)-3-deoxy-2-heptulosaric acid and rhamnosyl-rhamnosyl-(1----5)-3-deoxy-2-heptulosaric acid could be tentatively identified by mass spectrometric methods amongst the products of mild acidic hydrolysis of lipopolysaccharides of Rhizobium leguminosarum strain 24. The two types of non-nodulating mutants of Rhizobium leguminosarum included in this study did not contain 3-deoxy-2-heptulosaric acid.     

Isolation and Identification of trans-2- and trans-3-Hydroxy-1,8-cineole Glucosides from Alpinia galanga

Three hydroxy-1,8-cineole glucopyranosides, (1R,2R,4S)- and (1S,2S,4R)-trans-2-hydroxy-1,8-cineole β-D-glucopyranosides, and (1R,3S,4S)-trans-3-hydroxy-1,8-cineole β-D-glucopyranoside, which are possible precursors of acetoxy-1,8-cineoles as unique aroma components, were isolated from the rhizomes of greater galangal (Alpinia galanga W.). Their structures were analyzed by FAB-MS and NMR spectrometry, and the absolute configulation of each aglycone was determined by using a GC-MS analysis with a capillary column coated with a chiral stationary phase. The composition of the diastereomers of (1R,2R,4S)- and (1S,2S,4R)- trans-2-hydroxy-1,8-cineole β-D-glucopyranosides in the rhizomes was determined as 3:7 by a GC-MS analysis after preparing the trifluoroacetate derivatives of the glucosides.     

High Yield Synthesis of Nitriles by a New Enzyme,Phenylacetaldoxime Dehydratase,from Bacillus sp. Strain OxB-1

3-Phenylpropionitrile was synthesized from Z-3-phenylpropionaldoxime (0.75 M) in a quantitative yield (98 g/l) by the use of cells of Eschrichia coli JM 109/pOxD-9OF, a transformant harboring a gene for a new enzyme, phenylacetaldoxime dehydratase, from Bacillus sp. strain OxB-1. Other arylalkyl- and alkyl-nitriles were also synthesized in high yields from the corresponding aldoximes. Moreover, 3-phenylpropionitrile was successfully synthesized by the recombinant cells in 70 and 100% yields from 0.1 M unpurified E/Z-3-phenylpropionaldoxime, which is spontaneously formed from 3-phenylpropionaldehyde and hydroxylamine in a butyl acetate/water biphasic system and aqueous phase, respectively.     

Dormancy in peach (Prunus persica L.) flower buds

Morphological studies were carried out with peach flower buds collected monthly in 1989 and 1990, from two months before leaf fall (7 March) until two to three weeks before bloom (7/8 August). Chilled (2–4°C for 30 days) and unchilled buds were exposed to 20 to 25°C, 100% RH and continuous light. Gibberellin A₃ (3 ng or 30 ng) was applied to some of the non-chilled cuttings at three days intervals. Then, 12, 19, and 26 days after they were planted, the buds were sampled and processed for histological studies. Cultured flower buds (chilled or unchilled) had accelerated anther and gynoecium morphogenesis after 12 days under controlled conditions, compared to buds processed immediately after collection from the field. Chilling treatment augmented the bud culture effect, while Gibberellin A₃ applications to the excised buds retarded bud morphogenesis to a stage comparable to that of buds collected directly from the field. This, suggests that the comparatively high levels of Gibberellin A_1/3 we previously found in mid winter [15, 18] could be at least one of the factors that controls floral bud dormancy by retarding anther and gynoecium development.     

Rice G protein γ subunit qPE9-1 modulates root elongation for phosphorus uptake by involving 14-3-3 protein OsGF14b and plasma membrane H+-ATPase

Heterotrimeric G protein is involved in plant growth and development, while the role of rice (Oryza sativa) G protein γ subunit qPE9-1 in response to low-phosphorus (LP) conditions remains unclear. The gene expression of qPE9-1 was significantly induced in rice roots under LP conditions. Rice varieties carrying the qPE9-1 allele showed a stronger primary root response to LP than the varieties carrying the qpe9-1 allele (mutant of the qPE9-1 allele). Transgenic rice plants with the qPE9-1 allele had longer primary roots and higher P concentrations than those with the qpe9-1 allele under LP conditions. The plasma membrane (PM) H⁺-ATPase was important for the qPE9-1-mediated response to LP. Furthermore, OsGF14b, a 14-3-3 protein that acts as a key component in activating PM H⁺-ATPase for root elongation, is also involved in the qPE9-1 mediation. Moreover, the overexpression of OsGF14b in WYJ8 (carrying the qpe9-1 allele) partially increased primary root length under LP conditions. Experiments using R18 peptide (a 14-3-3 protein inhibitor) showed that qPE9-1 is important for primary root elongation and H⁺ efflux under LP conditions by involving the 14-3-3 protein. In addition, rhizosheath weight, total P content, and the rhizosheath soil Olsen-P concentration of qPE9-1 lines were higher than those of qpe9-1 lines under soil drying and LP conditions. These results suggest that the G protein γ subunit qPE9-1 in rice plants modulates root elongation for phosphorus uptake by involving the 14-3-3 protein OsGF14b and PM H⁺-ATPase, which is required for rice P use.     

UHRF2, a Ubiquitin E3 Ligase,Acts as a Small Ubiquitin-like Modifier E3 Ligase for Zinc Finger Protein 131

Small ubiquitin-like modifier (SUMO), a member of the ubiquitin-related protein family, is covalently conjugated to lysine residues of its substrates in a process referred to as SUMOylation. SUMOylation occurs through a series of enzymatic reactions analogous to that of the ubiquitination pathway, resulting in modification of the biochemical and functional properties of substrates. To date, four mammalian SUMO isoforms, a single heterodimeric SUMO-activating E1 enzyme SAE1/SAE2, a single SUMO-conjugating E2 enzyme ubiquitin-conjugating enzyme E2I (UBC9), and a few subgroups of SUMO E3 ligases have been identified. Several SUMO E3 ligases such as topoisomerase I binding, arginine/serine-rich (TOPORS), TNF receptor-associated factor 7 (TRAF7), and tripartite motif containing 27 (TRIM27) have dual functions as ubiquitin E3 ligases. Here, we demonstrate that the ubiquitin E3 ligase UHRF2 also acts as a SUMO E3 ligase. UHRF2 effectively enhances zinc finger protein 131 (ZNF131) SUMOylation but does not enhance ZNF131 ubiquitination. In addition, the SUMO E3 activity of UHRF2 on ZNF131 depends on the presence of SET and RING finger-associated and nuclear localization signal-containing region domains, whereas the critical ubiquitin E3 activity RING domain is dispensable. Our findings suggest that UHRF2 has independent functional domains and regulatory mechanisms for these two distinct enzymatic activities.