Enhancement of 1-deoxynojirimycin production in mulberry (Morus spp.) using LED irradiation

Plant Cell, Tissue and Organ Culture (PCTOC) - 1-Deoxynojirimycin (DNJ), one of the main bioactive compounds in mulberry plants, is a strong inhibitor of α-glucosidase with potential...     

Putative cis-elements in the promoter region of the carrot phenylalanine ammonia-lyase gene induced during anthocyanin synthesis

Deletion mutants of the carrot phenylalanine ammonia-lyase gene promoter were used to survey cis-elements for their effect on expression of promoter activity by transient expression. Two putative cis-elements were required to give full activity, but a third might be the most important in regulation of the promoter by 2,4-dichlorophenoxyacetic acid. Electronic Publication     

Evidence for a SAL1-PAP chloroplast retrograde pathway that functions in drought and high light signaling in Arabidopsis

Compartmentation of the eukaryotic cell requires a complex set of subcellular messages, including multiple retrograde signals from the chloroplast and mitochondria to the nucleus, to regulate gene expression. Here, we propose that one such signal is a phosphonucleotide (3'-phosphoadenosine 5'-phosphate [PAP]), which accumulates in Arabidopsis thaliana in response to drought and high light (HL) stress and that the enzyme SAL1 regulates its levels by dephosphorylating PAP to AMP. SAL1 accumulates in chloroplasts and mitochondria but not in the cytosol. sal1 mutants accumulate 20-fold more PAP without a marked change in inositol phosphate levels, demonstrating that PAP is a primary in vivo substrate. Significantly, transgenic targeting of SAL1 to either the nucleus or chloroplast of sal1 mutants lowers the total PAP levels and expression of the HL-inducible ASCORBATE PEROXIDASE2 gene. This indicates that PAP must be able to move between cellular compartments. The mode of action for PAP could be inhibition of 5' to 3' exoribonucleases (XRNs), as SAL1 and the nuclear XRNs modulate the expression of a similar subset of HL and drought-inducible genes, sal1 mutants accumulate XRN substrates, and PAP can inhibit yeast (Saccharomyces cerevisiae) XRNs. We propose a SAL1-PAP retrograde pathway that can alter nuclear gene expression during HL and drought stress.     

Life cycle assessment of mini-hydropower plants in Thailand

Purpose  

The conversion of electricity in Thailand is mainly based on fossil fuels that account more than 90% of electricity generated in the country. The use of fossil fuels has large environmental impacts, and being largely imported, also affects the energy security of the country. From the oil shock situation in 1970s, there has been interest in renewable energy in Thailand resulting in the policy goal for the year 2020 to increase the portion of renewable energy to 20% of energy used in the country. Now, hydropower contributes a significant portion of the renewable energy in Thailand, and mini-hydropower (run-of-river type with capacity between 200 to 6000 kW) tends to be most attractive. This is particularly suitable for Thailand, and it is being applied at several locations. Thus, the overall life cycle assessment (LCA), from cradle to gate, of mini-hydropower plants needs to be assessed for quantitative evaluation.     

The nucleotidase/phosphatase SAL1 is a negative regulator of drought tolerance in Arabidopsis

An Arabidopsis thaliana drought-tolerant mutant, altered expression of APX2 ( alx8 ), has constitutively increased abscisic acid (ABA) content, increased expression of genes responsive to high light stress and is reported to be drought tolerant. We have identified alx8 as a mutation in SAL1, an enzyme that can dephosphorylate dinucleotide phosphates or inositol phosphates. Previously identified mutations in SAL1, including fiery ( fry1-1 ), were reported as being more sensitive to drought imposed by detachment of rosettes. Here we demonstrate that alx8 , fry1-1 and a T-DNA insertional knockout allele all have markedly increased resistance to drought when water is withheld from soil-grown intact plants. Microarray analysis revealed constitutively altered expression of more than 1800 genes in both alx8 and fry1-1. The up-regulated genes included some characterized stress response genes, but few are inducible by ABA. Metabolomic analysis revealed that both mutants exhibit a similar, dramatic reprogramming of metabolism, including increased levels of the polyamine putrescine implicated in stress tolerance, and the accumulation of a number of unknown, potential osmoprotectant carbohydrate derivatives. Under well-watered conditions, there was no substantial difference between alx8 and Col-0 in biomass at maturity; plant water use efficiency (WUE) as measured by carbon isotope discrimination; or stomatal index, morphology or aperture. Thus, SAL1 acts as a negative regulator of predominantly ABA-independent and also ABA-dependent stress response pathways, such that its inactivation results in altered osmoprotectants, higher leaf relative water content and maintenance of viable tissues during prolonged water stress.     

The dual role of carbenicillin in shoot regeneration and somatic embryogenesis of horseradish (<Emphasis Type="Italic">Armoracia rusticana</Emphasis>) in vitro

Carbenicillin, a well-known antibiotic, has been reported to have growth regulator-like activity in vitro for some plant species. In the present paper we add horseradish (Armoracia rusticana) to the list of plants exhibiting such responses. This project began as an effort to eliminate latent bacterial contamination among established in vitro horseradish plants. Carbenicillin (100 mg L⁻¹) added to regeneration medium eliminated all visible bacterial contaminants. Unexpectedly, carbenicillin-grown explants regenerated adventitious shoots faster (14 days) than those on control medium (21 days). In addition eight of 11 horseradish cultivars grown on carbenicillin produced more adventitious shoots per explant than control. At much higher levels (2,000 mg L⁻¹) carbenicillin was found to retard somatic embryogenic callus induction. Based on these observations we suggest that carbenicillin at moderate levels enhances shoot development in horseradish. The mode of action of carbenicillin’s growth regulator-like activity needs to be investigated.     

Molecular heterogeneity of the SHAP-hyaluronan complex. Isolation and characterization of the complex in synovial fluid from patients with rheumatoid arthritis

We previously found that a covalent complex of SHAPs (serum-derived hyaluronan-associated proteins), the heavy chains of inter-alpha-trypsin inhibitor family molecules, with hyaluronan (HA) is accumulated in synovial fluid of patients with rheumatoid arthritis, and the complex is circulated in patient plasma at high concentrations. How the SHAP-HA complex participates in this disease is unknown. To address this question, it is essential to clarify the structural features of this macromolecule. The SHAP-HA complex purified from synovial fluid of the patients by three sequential CsCl isopycnic centrifugations was heterogeneous in density, and the fractions with different densities had distinct SHAP-to-HA ratios. Agarose gel electrophoresis and column chromatography revealed that there was no apparent difference in the size distribution of HA to which SHAPs were bound between the fractions with different densities. The SHAP-HA complex in the higher density fraction had fewer SHAP molecules per HA chain. Therefore, the difference between the fractions with different densities was due to a heterogeneous population of the SHAP-HA complex, namely the different number of SHAP molecules bound to an HA chain. Based on the SHAP and HA contents of the purified preparations, we estimated that an HA chain with a molecular weight of 2 x 106 has as many as five covalently bound SHAPs, which could give a proteinaceous multivalency to HA. Furthermore, we also found that the SHAP-HA complex tends to form aggregates, judging from the migration and elution profiles in agarose gel electrophoresis and gel filtration, respectively. The multivalent feature of the SHAP-HA complex was also confirmed by the negative staining electron micrographic images of the purified fractions. Taken together, those structural characteristics may underlie the aggregate-forming and extracellular matrix-stabilizing ability of the SHAP-HA complex.     

Computational analyses of curcuminoid analogs against kinase domain of HER2

Background

Human epidermal growth factor receptor 2 (HER2) has an important role in cancer aggressiveness and poor prognosis. HER2 has been used as a drug target for cancers. In particular, to effectively treat HER2-positive cancer, small molecule inhibitors were developed to target HER2 kinase. Knowing that curcumin has been used as food to inhibit cancer activity, this study evaluated the efficacy of natural curcumins and curcumin analogs as HER2 inhibitors using in vitro and in silico studies. The curcumin analogs considered in this study composed of 4 groups classified by their core structure, β-diketone, monoketone, pyrazole, and isoxazole.

Results

In the present study, both computational and experimental studies were performed. The specificity of curcumin analogs selected from the docked results was examined against human breast cancer cell lines. The screened curcumin compounds were then subjected to molecular dynamics simulation study. By modifying curcumin analogs, we found that protein-ligand affinity increases. The benzene ring with a hydroxyl group could enhance affinity by forming hydrophobic interactions and the hydrogen bond with the hydrophobic pocket. Hydroxyl, carbonyl or methoxy group also formed hydrogen bonds with residues in the adenine pocket and sugar pocket of HER2-TK. These modifications could suggest the new drug design for potentially effective HER2-TK inhibitors. Two outstanding compounds, bisdemethylcurcumin (AS-KTC006) and 3,5-bis((E)-3,4-dimethoxystyryl)isoxazole (AS-KTC021 ),were well oriented in the binding pocket almost in the simulation time, 30 ns. This evidence confirmed the results of cell-based assays and the docking studies. They possessed more distinguished interactions than known HER2-TK inhibitors, considering them as a promising drug in the near future.

Conclusions

The series of curcumin compounds were screened using a computational molecular docking and followed by human breast cancer cell lines assay. Both AS-KTC006 and AS-KTC021 could inhibit breast cancer cell lines though inhibiting of HER2-TK. The intermolecular interactions were confirmed by molecular dynamics simulation studies. This information would explore more understanding of curcuminoid structures and HER2-TK.

Electronic supplementary material

The online version of this article (doi:10.1186/1471-2105-15-261) contains supplementary material, which is available to authorized users.