Micropropagation,berberine content and antitumor activity of Jeffersonia dubia (Maxim.) Benth et Hook

An efficient micropropagation protocol was developed for Jeffersonia dubia using sucker explants. High frequency of multiple shoot formation was induced when the sucker explants were cultured on Chu’s (N6) medium with different concentrations of thidiazuron (TDZ) plus 0.54 µM α-naphthaleneacetic acid (NAA). The maximum frequency of shoot formation (96.2 %) was obtained on N6 medium with 2.27 µM TDZ plus 0.54 µM NAA. The highest mean number of shoots per explant (13.6) was obtained in temporary immersion system using an immersion frequency of 30 s every 30 min. The highest frequency of rooting (100 %), number of roots per shoot (5.8), and root length (6.3) was observed in half-strength N6 medium supplemented with 2.69 µM NAA. The regenerated plantlets (30 days old) were successfully acclimatized in the greenhouse with 98 % survival rate. The berberine content and cytotoxicity were higher in in vitro-developed calli and shoots than in leaves of field-grown plants. The greatest content of berberine was found in shoots (1381 μg g⁻¹) followed by calli (1092 μg g⁻¹) and leaves of field-grown plants (92 μg g⁻¹). At 1000 μg mL⁻¹ concentration, growth inhibition rate of berberine, callus, shoot, and leaf (in vivo) extracts were 68.4, 57.1, 54.2, and 17.7 %, respectively.

     

The tyrosinase inhibitory effects of isoxazolone derivatives with a (Z)-β-phenyl-α, β-unsaturated carbonyl scaffold

Thirteen (Z)-4-(substituted benzylidene)-3-phenylisoxazol-5(4H)-ones were designed to confirm the geometric effect of the double bond of the β-phenyl-α, β-unsaturated carbonyl scaffold on tyrosinase inhibitory activity. Compounds 1a–1m, which all possessed the (Z)-β-phenyl-α, β-unsaturated carbonyl scaffold, were synthesized using a tandem reaction consisting of an isoxazolone ring formation and a Knoevenagel condensation, and three starting materials, ethyl benzoylacetate, hydroxylamine and benzaldehydes. Some of the compounds showed inhibitory activity against mushroom tyrosinase as potent as compounds containing the “(E)”-β-phenyl-α, β-unsaturated carbonyl scaffold. Compounds 1c and 1m showed greater inhibitory activity than kojic acid: IC₅₀?=?32.08?±?2.25?μM for 1c; IC₅₀?=?14.62?±?1.38?μM for 1m; and IC₅₀?=?37.86?±?2.21?μM for kojic acid. A kinetic study indicated that 1m inhibited tyrosinase in a competitive manner and that it probably binds to the enzyme’s active site. In silico docking simulation supported binding of 1m (?7.6?kcal/mol) to the active site of tyrosinase with stronger affinity than kojic acid (?5.7?kcal/mol). Similar results were obtained using cell-based assays, and in B16F10 cells, compound 1m dose-dependently inhibited tyrosinase activity and melanogenesis. These results indicate the anti-melanogenic effect of compound 1m is due to the inhibition of tyrosinase and (Z)-isomer of the β-phenyl-α, β-unsaturated carbonyl scaffold can, like its congener the (E)-isomer, act as an excellent scaffold for tyrosinase inhibition.     

Transgenic tomato plants expressing strawberry <Emphasis Type="ItalicSmallCaps">d</Emphasis>-<Emphasis Type="Italic">galacturonic acid reductase</Emphasis> gene display enhanced tolerance to abiotic stresses

After analyzing tomato plants transformed with GalUR gene for their ascorbic acid contents, it was found that some transgenic lines contained higher levels of ascorbic acid compared to control plants. In the present study, callus induction rate was 50.2 % in the explant and shoot regeneration rate was 51.5 % from the callus with transformation efficiency of 3.0 %. Based on PCR and Southern blot analysis, three independent transformants containing the insert gene were selected. Phenotypic traits of these transgenic progeny were similar to those of control tomatoes. Tomatoes (H15) with high fruit ascorbic acid contents were selected for next generation (GalUR T₃) analysis. Transgenic tomatoes with increased ascorbic acid contents were found to be more tolerant to abiotic stresses induced by viologen, NaCl, or mannitol than non-transformed plants. In leaf disc senescence assay, the tolerance of these transgenic plants was better than control plants because they could retain higher chlorophyll contents. Under salt stress of less than 200 mM NaCl, these transgenic plants survived. However, control plants were unable to survive such high salt stress. Ascorbic acid contents in the transgenic plants were inversely correlated with MDA contents, especially under salt stress conditions. The GalUR gene was expressed in H15 tomatoes, but not in control plants. Higher expression levels of antioxidant genes (APX and CAT) were also found in these transgenic plants compared to that in the control plants. However, no detectable difference in SOD expression was found between transgenic plants and control plants. Results from this study suggest that the increase in ascorbic acid contents in plants could up-regulate the antioxidant system to enhance the tolerance of transgenic tomato plants to various abiotic stresses.     

A role of Anabaena sensory rhodopsin transducer (ASRT) in photosensory transduction

In 2003, Anabaena sensory rhodopsin (ASR), a membrane‐bound light sensor protein, was discovered in cyanobacteria. Since then, a large number of functions have been described for ASR, based on protein biochemical and biophysical studies. However, no study has determined the in vivo mechanism of photosensory transduction for ASR and its transducer protein (ASRT). Here, we aimed to determine the role of ASRT in physiological photo‐regulation. ASRT is known to be related to photochromism, because it regulates the expression of phycocyanin (cpc‐gene) and phycoerythrocyanin (pec gene), two major proteins of the phycobilisome in cyanobacteria. By examining wild type and knockout mutant Anabaena cells, we showed that ASRT repressed the expression of these two genes. We also demonstrated physical interactions between ASRT, ASR, and the promoter regions of cpc, pec, kaiABC (circadian clock gene) and the asr operon, both in vitro and in vivo. Binding assays indicated that ASRT had different sites of interaction for binding to ASR and DNA promoter regions. ASRT also influenced the retinal re‐isomerization rate in dark through a physical interaction with ASR, and it regulated reporter gene expression in vivo. These results suggested that ASRT relayed the photosignal from ASR and directly regulated gene expression.     

Draft genome sequence of Pantoea ananatis B1-9, a nonpathogenic plant growth-promoting bacterium

Pantoea ananatis B1-9 is an endophytic Gram-negative rhizobacterium that was isolated for its ability to promote plant growth and improve crop yield in the field. Here we report the draft genome sequence of P. ananatis B1-9. Comparison of this sequence to the sequenced genome of a plant-pathogenic P. ananatis strain, LMG20103, indicated that the pathogenesis-related genes were absent, but a subset of gene functions that may be related to its plant growth promotion were present.     

Proteomic analysis in NSAIDs-treated primary cardiomyocytes

NSAIDs (non-steroidal anti-inflammatory drugs) are widely used for the treatment of a variety of inflammatory diseases, but many of them were withdrawn from the market due to their cardiovascular toxicity. In this study, we tried to identify proteins responding to the cellular toxicity in NSAIDs-treated primarily cultured cardiomyocytes using 2-D proteomic analysis. We used seven different NSAIDs (celecoxib, rofecoxib, valdecoxib, diclofenac, naproxen, ibuprofen, and meloxicam) possessing each different degree of cardiovascular risk. Overall protein spots were similar in all NSAIDs-treated cells although numbers of decreased proteins were about 2-fold higher in celecoxib or rofecoxib-treated cells than in cells incubated with other NSAIDs. Many stress-related proteins, cardiac muscle movement proteins and proteins involved in membrane organization have been isolated. Among them, Septin-8, a filament scaffolding protein, showed its specific expression pattern depending on the extent of drug toxicity. Its expression level was low in cells treated by relatively high toxic drugs such as celecoxib, diclofenac, valdecoxib, and rofecoxib. On the contrary, Septin-8 was similarly expressed in control cells in the presence of less toxic drugs such ibuprofen, naproxen, and meloxicam. This data suggests that Septin-8 differentially responds to each NSAID.     

Chromosomal Polymorphism in Korean Natural Populations of Drosophila immigrans

ABSTRACT To analyze chromosome inversions of Drosophila immigrans , wild flies were captured from large vineyards located in the suburbs of Yecheon and Gyeongsan from October 1999 to 2001. With the egg samples obtained singly at each of the 799 females of D. immigrans , cytological examinations were carried out for the type and frequency of inversions. Two types of different inversions were found only in the second chromosome. The inversions detected were known to be the cosmopolitan inversion "A" and "B". The mean frequency of inversion A was estimated to be 0.074 in Yecheon and 0.066 in Gyeongsan and that of B was to be 0.026 in Yecheon and 0.021 in Gyeongsan, respectively. In the frequency ratio, inversion A was significantly higher than that of B. The present populations of D. immigrans showed subtle differences from other Korean populations in inversion frequencies. To account for the local variations observed in inversion frequencies, several hypotheses are discussed such as founding event or selective force.     

Synthesis and Antiviral Activity of L-2′-Deoxy-2′-up-fluoro-4′-thionucleosides

Abstract

L-2′-Deoxy-2′-up-fluoro-4′-thionucleosides were efficiently synthesized from D-xylose via L-4-thioarabitol derivative as a key intermediate and evaluated for antiviral activities against HIV-1, HSV-1,2 and HBV.