Two diterpene alcohols from Croton sublyratus

The isolation and structural elucidation of two diterpene alcohols from Croton sublyratus are described. These compounds are ent-3α-hydroxy-13-epimanool and ent-16β,17-dihydroxykaurane.     

New Diterpenes of Torreya nucifera Sieb. et Zucc.

Three new labdane type diterpenes; 4-epiagathadiol (named kayadiol), 18-hydroxymanool (named torreferol), 18-hydroxy-13-epimanool (named 13-epitorreferol), were isolated from the non-steam-volatile fraction of leaves of Torreya nucifera Sieb. et Zucc. (Taxaceae, Japanese name “Kaya”).

This is the first reported isolation these three diterpenes in a natural source.     

Expression of a wild eggplant ribosomal protein L13a in potato enhances resistance to Verticillium dahliae

The ribosomal protein L13a was recently found to play a role not only in protein synthesis, but also in modulating translation. We reported in previous study that L13a was responsive to Verticillium dahliae (V. dahliae) infection in a highly resistant eggplant species (Solanum torvum, SW). To elucidate the possible role of L13a in V. dahliae infection, we cloned and characterized its cDNA (designated StoL13a) in this study. StoL13a encodes a protein of 23.46 kDa and shows a high similarity to the L13a from other plants. Phylogenetic analysis revealed that StoL13a clearly grouped with L13a-like sequences. Expression level of StoL13a altered in response to V. dahliae infection and phytohormone treatment. We expressed StoL13a in V. dahliae sensitive potato, and found that the transgenic potato plants were more resistant to V. dahliae infection than the control plants with disease index of 15–25.2. The transgenic plants showed a lower quantity of reactive oxygen species and attenuated oxidative injury. Also, six defense and antioxidant enzyme genes were up-regulated in the StoL13a ectopic expression plants. These results suggest that the StoL13a plays a role in plant defense to V. dahliae infection.     

p13 from group II baculoviruses is a killing-associated gene

p13 gene was first described in Leucania separata multinuclear polyhedrosis virus (Ls-p13) several years ago, but the function of P13 protein has not been experimentally investigated to date. In this article, we indicated that the expression of p13 from Heliothis armigera single nucleocapsid nucleopolyhedrovirus (Ha-p13) was regulated by both early and late promoter. Luciferase assay demonstrated that the activity of Ha-p13 promoter with hr4 enhancer was more than 100 times in heterologous Sf9 cells than that in nature host Hz-AM1 cells. Both Ls-P13 and Ha-P13 are transmembrane proteins. Confocal microscopic analysis showed that both mainly located in the cytoplasm membrane at 48 h. Results of RNA interference indicated that Ha-p13 was a killing-associated gene for host insects H. armigera. The AcMNPV acquired the mentioned killing activity and markedly accelerate the killing rate when expressing Ls-p13. In conclusion, p13 is a killing associated gene in both homologous and heterologous nucleopolyhedrovirus. [BMB Reports 2012; 45(12): 730-735]     

Synthesis of oligomethylene-strapped chlorophyll derivatives and optical properties of their stereoisomers in a solution

Methyl pheophorbide-a/a′ derivatives covalently linked with oligomethylene chains at the 3-CH₂OCO– and 13²-COO– moieties in a molecule were prepared by modifying chlorophyll-a through intramolecular ring-closing metathesis of vinyl groups. At least, a C10-length between the 3³- and 13⁴-positions was necessary for the cyclization and connection of a C12-strap was the most suitable to achieve the highest closure yield. The oligomethylene chain in 13² R-epimers derived from methyl pheophorbide-a covered the α-face of the chlorin π-plane and the strap in the corresponding 13² S-epimers protected the β-face. Synthetic 13² R-epimer with a dodecamethylene chain gave a flat chlorin π-plane, while the decamethylene chain in the 13² R-epimer distorted the π-system due to its shorter linkage. The distortion by strapping in the 13² R-epimer induced a slight blue-shift of Qy peak in dichloromethane. CD spectra of the 13² R-epimers were similarly dependent on the chain length, i.e., the distortion of π-plane. Visible absorption and CD spectra of all the strapped 13² S-epimers were almost identical and only slightly different from those of the unstrapped. The strapping in the 13² S-epimers shifted the Qy peak bathochromically.     

Labdane diterpenoid glycosides from Aster veitchianus

Four new labdane-type rhamnopyranosides derived from 13-epimanool, compounds 1-4, with differently acetylated sugar moieties, were isolated from A. veitchianus. Their structures and absolute configurations were elucidated by chemical transformation, spectroscopic and mass-spectrometric analyses (IR, 1D- and 2D-NMR, HR-ESI-MS), as well as by single-crystal X-ray diffraction (compound 1). The isolates 2-4 were investigated for their cytotoxic properties against cultured human hepatoma (SMMC-7721), ovarian neoplasm (HO-8910), and leukemia (HL-60) cells, and for their antibacterial activities against Escherichia coli, Bacillus subtilis, and Staphylococcus aureus.     

Hydroperoxide Lyase and Other Hydroperoxide-Metabolizing Activity in Tissues of Soybean, Glycine max

Hydroperoxide lyase (HPLS) activity in soybean (Glycine max) seed/seedlings, leaves, and chloroplasts of leaves required detergent solubilization for maximum in vitro activity. On a per milligram of protein basis, more HPLS activity was found in leaves, especially chloroplasts, than in seeds or seedlings. The total yield of hexanal from 13(S)-hydroperoxy-cis-9,trans-11-octadecadienoic acid (13S-HPOD) from leaf or chloroplast preparations was 58 and 66 to 85%, respectively. Because of significant competing hydroperoxide-metabolizing activities from other enzymes in seed/seedling preparations, the hexanal yields from this source were lower (36-56%). Some of the products identified from the seed or seedling preparations indicated that the competing activity was mainly due to both a hydroperoxide peroxygenase and reactions catalyzed by lipoxygenase. Different HPLS isozyme compositions in the seed/seedling versus the leaf/chloroplast preparations were indicated by differences in the activity as a function of pH, the K_m values, relative V_max with 13S-HPOD and 13(S)-hydroperoxy-cis-9,trans-11,cis-15-octadecatrienoic acid (13S-HPOT), and the specificity with different substrates. With regard to the latter, both seed/seedling and chloroplast HPLS utilized the 13S-HPOD and 13S-HPOT substrates, but only seeds/seedlings were capable of metabolizing 9(S)-hydroperoxy-trans-10,cis-12-octadecadienoic acid into 9-oxononanoic acid, isomeric nonenals, and 4-hydroxynonenal. From 13S-HPOD and 13S-HPOT, the products were identified as 12-oxo-cis-9-dodecenoic acid, as well as hexanal from 13S-HPOD and cis-3-hexenal from 13S-HPOT. In seed preparations, there was partial isomerization of the cis-3 or cis-9 into trans-2 or trans-10 double bonds, respectively.     

Mcp7, a meiosis-specific coiled-coil protein of fission yeast, associates with Meu13 and is required for meiotic recombination

We previously showed that Meu13 of Schizosaccharomyces pombe functions in homologous pairing and recombination at meiosis I. Here we show that a meiosis-specific gene encodes a coiled-coil protein that complexes with Meu13 during meiosis in vivo. This gene denoted as mcp7⁺ (after meiotic coiled-coil protein) is an ortholog of Mnd1 of Saccharomyces cerevisiae. Mcp7 proteins are detected on meiotic chromatin. The phenotypes of mcp7Δ cells are similar to those of meu13Δ cells as they show reduced recombination rates and spore viability and produce spores with abnormal morphology. However, a delay in initiation of meiosis I chromosome segregation of mcp7Δ cells is not so conspicuous as meu13Δ cells, and no meiotic delay is observed in mcp7Δmeu13Δ cells. Mcp7 and Meu13 proteins depend on each other differently; Mcp7 becomes more stable in meu13Δ cells, whereas Meu13 becomes less stable in mcp7Δ cells. Genetic analysis shows that Mcp7 acts in the downstream of Dmc1, homologs of Escherichia coli RecA protein, for both recombination and subsequent sporulation. Taken together, we conclude that Mcp7 associates with Meu13 and together they play a key role in meiotic recombination.     

Esterase 13, a new mouse esterase locus with recessive expression and its genetic location on chromosome 9

A new esterase locus (Es-13) has been identified in Mus musculus. Strains AEJ/GnRk, LG/J, SJL/J, and SWR/J carry a recessive allele, Es-13 ^b, for a locus possibly involved in the posttranslational modification of a kidney esterase. All other strains observed carried the dominant Es-13 ^a allele. Es-13 was mapped on Chr 9 by recombinant inbred lines and by conventional backcrossing experiments. Backcross data produced the following gene order and map distances: Lap-1 (31.6±7.5 cM) Es-13 (2.6±2.6 cM) Mod-1.     

Mutations in MMP9 and MMP13 Determine the Mode of Inheritance and the Clinical Spectrum of Metaphyseal Anadysplasia

The matrix metalloproteinases MMP9 and MMP13 catalyze the degradation of extracellular matrix (ECM) components in the growth plate and at the same time cleave and release biologically active molecules stored in the ECM, such as VEGFA. In mice, ablation of Mmp9, Mmp13, or both Mmp9 and Mmp13 causes severe distortion of the metaphyseal growth plate. We report that mutations in either MMP9 or MMP13 are responsible for the human disease metaphyseal anadysplasia (MAD), a heterogeneous group of disorders for which a milder recessive variant and a more severe dominant variant are known. We found that recessive MAD is caused by homozygous loss of function of either MMP9 or MMP13, whereas dominant MAD is associated with missense mutations in the prodomain of MMP13 that determine autoactivation of MMP13 and intracellular degradation of both MMP13 and MMP9, resulting in a double enzymatic deficiency.     

A Conserved Function in Phosphatidylinositol Metabolism for Mammalian Vps13 Family Proteins

The Vps13 protein family is highly conserved in eukaryotic cells. In humans, mutations in the gene encoding the family member VPS13A lead to the neurodegenerative disorder chorea-acanthocytosis. In the yeast Saccharomyces cerevisiae, there is just a single version of VPS13, thereby simplifying the task of unraveling its molecular function(s). While VPS13 was originally identified in yeast by its role in vacuolar sorting, recent studies have revealed a completely different function for VPS13 in sporulation, where VPS13 regulates phosphatidylinositol-4-phosphate (PtdIns(4)P) levels in the prospore membrane. This discovery raises the possibility that the disease phenotype associated with vps13A mutants in humans is due to misregulation of PtdIns(4)P in membranes. To determine whether VPS13A affects PtdIns(4)P in membranes from mammalian neuronal cells, phosphatidylinositol phosphate pools were compared in PC12 tissue culture cells in the absence or presence of VPS13A. Consistent with the yeast results, the localization of PtdIns(4)P is specifically altered in VPS13A knockdown cells while other phosphatidylinositol phosphates appear unaffected. In addition, VPS13A is necessary to prevent the premature degeneration of neurites that develop in response to Nerve Growth Factor. The regulation of PtdIns(4)P is therefore a conserved function of the Vps13 family and may play a role in the maintenance of neuronal processes in mammals.     

Tri13 and Tri7 Determine Deoxynivalenol- and Nivalenol-Producing Chemotypes of Gibberella zeae

Gibberella zeae, a major cause of cereal scab, can be divided into two chemotypes based on production of the 8-ketotrichothecenes deoxynivalenol (DON) and nivalenol (NIV). We cloned and sequenced a Tri13 homolog from each chemotype. The Tri13 from a NIV chemotype strain (88-1) is located in the trichothecene gene cluster and carries an open reading frame similar to that of Fusarium sporotrichioides, whereas the Tri13 from a DON chemotype strain (H-11) carries several mutations. To confirm the roles of the Tri13 and Tri7 genes in trichothecene production by G. zeae, we genetically altered toxin production in 88-1 and H-11. In transgenic strains, the targeted deletion of Tri13 from the genome of 88-1 caused production of DON rather than NIV. Heterologous expression of the 88-1 Tri13 gene alone or in combination with the 88-1 Tri7 gene conferred on H-11 the ability to synthesize NIV; in the latter case, 4-acetylnivalenol (4-ANIV) also was produced. These results suggest that Tri13 and Tri7 are required for oxygenation and acetylation of the oxygen at C-4 during synthesis of NIV and 4-ANIV in G. zeae. These functional analyses of the Tri13 and Tri7 genes provide the first clear evidence for the genetic basis of the DON and NIV chemotypes in G. zeae.     

Seasonal variations in bulk tissue, fatty acid and monosaccharide δC values of leaves from mesotrophic grassland plant communities under different grazing managements

Leaves of 26 grass, herb, shrub and tree species were collected from mesotrophic grasslands to assess natural variability in bulk, fatty acid and monosaccharide δ¹³C values under different grazing management (cattle- or deer-grazed) on three sample dates (May, July and October) such that interspecific and spatiotemporal variations in whole leaf tissues and compound-specific δ¹³C values could be determined. The total mean leaf bulk δ¹³C value for plants was −28.9‰ with a range of values spanning 7.5‰. Significant interspecific variation between bulk leaf δ¹³C values was only determined in October (P = <0.001) when δ¹³C values of the leaf tissues from both sites was on average 1.5‰ depleted compared to during July and May. Samples from May were significantly different between fields (P = 0.03) indicating an effect from deer- or cattle-grazing in young leaves. The average individual monosaccharide δ¹³C value was 0.8‰ higher compared with whole leaf tissues. Monosaccharides were the most abundant components of leaf biomass, i.e. arabinose, xylose, mannose, galactose and glucose, and therefore, fluctuations in their individual δ¹³C values had a major influence on bulk δ¹³C values. An average depletion of ca. 1‰ in the bulk δ¹³C values of leaves from the deer-grazed field compared to the cattle-grazed field could be explained by a general depletion of 1.1‰ in glucose δ¹³C values, as glucose constituted >50% total leaf monosaccharides. In October, δ¹³C values of all monosaccharides varied between species, with significant variation in δ¹³C values of mannose and glucose in July, and mannose in May. This provided an explanation for the noted variability in the tissue bulk δ¹³C values observed in October 1999. The fatty acids C_16:0, C_18:2 and C_18:3 were highly abundant in all plant species. Fatty acid δ¹³C values were lower than those of bulk leaf tissues; average values of −37.4‰ (C_16:0), −37.0‰ (C_18:2) and −36.5‰ (C_18:3) were determined. There was significant interspecific variation in the δ¹³C values of all individual fatty acids during October and July, but only for C_18:2 in May (P = <0.05). This indicated that seasonal trends observed in the δ¹³C values of individual fatty acids were inherited from the isotopic composition of primary photosynthate. However, although wide diversity in δ¹³C values of grassland plants ascribed to grazing management, interspecific and spatiotemporal influences was revealed, significant trends (P = <0.0001) for fatty acid and monosaccharide δ¹³C values: δ¹³C_16:0 < δ¹³C_18:2 < δ¹³C_18:3 and δ¹³C_arabinose > δ¹³C_xylose > δ¹³C_glucose > δ¹³C_galactose, respectively, previously described, appear consistent across a wide range of species at different times of the year in fields under different grazing regimes.