Effects of SclR on metabolite production in Aspergillus oryzae | Author : Feng-Jie Jin | Abstract | Full Text | Abstract :Aspergillus oryzae, an industrially important fungus utilized for the traditional fermentative manufacturing, produces diverse metabolites and enzymes during fermentation. In our previous study, we have ever identified and characterized a basic helix-loop-helix (bHLH) transcription factor, SclR, and found that the transcription factor is importantly involved in the conidiation, sclerotial formation, and hyphal morphology in A. oryzae. In this study, we further analyzed the effect of SclR on metabolites production in A. oryzae. The control strain and ?sclR strain were cultivated in dextrin-polypeptone-yeast extract (DPY) liquid medium at 30 °C for 3 days and metabolites were extracted from strains. Liquid chromatography–mass spectrometry (LC-MS) analysis result showed that a total of 1,855 precursor molecules were obtained in the positive ion mode and 2,475 precursor molecules were obtained in the negative ion mode. Comparative analysis of the metabolome indicated that 259 were differentially expressed metabolites. Among of them, 161 metabolites were increased by 1.5-fold, and 98 metabolites were decreased by 1.5-fold in an sclR gene deletion strain compared to the control. Further identification of differentially expressed metabolites revealed that the production level of some organic acids, amino acids, and sugar alcohols were markedly changed in ?sclR strain relative to control strain. Especially, some organic acids were identified to be intermediates in the citric acid cycle, which is a key metabolic pathway that connects carbohydrate, fat, and protein metabolism. The result also implied that the SclR is potentially involved in energy metabolism. |
| Isolation and Identification of procyanidins in Aronia Melanocarpa Using NMR, LC-IT-TOF/MS/MS and MALDI-TOF MS | Author : Aidong Sun | Abstract | Full Text | Abstract :Aronia melanocarpa berries procyanidins (Amps) were divided in three fractions: ethyl acetate phase extract of Amps (E-Amps), aqueous phase extract of Amps (W-Amps), and methanol phase extract of Amps (M-Amps). Flavan-3-ol monomers and oligomeric procyanidins were isolated from E-Amps using Sephadex LH-20 column chromatography and reversed-phase preparative HPLC. 1H and 13C NMR analyses indicated five flavan-3-ol monomers and oligomeric procyanidins: (+)- catechin, (?)- epicatechin, procyanidin B2 [EC-(4ß?8)-EC], procyanidin B1 [EC-(4ß?8)-C], and procyanidin C1 [EC-(4ß?8)-EC-(4ß?8)-EC]. MALDI-TOF-MS analysis demonstrated that the structure units of polymeric Amps, which were linked by B-type bonds, contained only catechin and epicatechin. In addition, the degree of polymerization was from pentamer to twenty-two polymer. Five flavan-3-ol monomers and oligomeric procyanidins had strong antioxidant activities. The DPPH and ABTS free-radical scavenging capacities followed the order: flavan-3-ol monomers > dimeric procyanidins > trimeric procyanidins > ascorbic acid. However, FRAP values increased with a degree of polymerization.
Keywords: Aronia melanocarpa berries; Procyanidins; Structural identification; Antioxidant activity. |
| Crystal engineering of fisetin: a step towards improved biopharmaceutical parameters | Author : Renu Chadha | Abstract | Full Text | Abstract :Background: In the present study, crystal engineering strategy is employed to facilitate the supramolecular synthesis of three new crystalline forms of a potential flavonoidal molecule, Fisetin whose efficacy is hampered due to its low solubility. Fisetin cocrystals with GRAS status coformers including glutaric acid, malic acid and theophylline are described herein. All the coformers complement the phytogen with respect to hydrogen bonding. .
Method: Mechanochemical grinding was utilized to prepare the cocrystals i.e., FGLU, FMAL and FTHY which were analyzed using DSC, FT-IR, PXRD and solid state NMR. The crystal structures determined using the PXRD pattern validated the existence of FGLU (triclinic crystal system (P1), FMAL (monoclinic P21/c) and FTHY(triclinic crystal system (P1). In each of the crystal structures, intermolecular hydrogen-bonding motif involving the hydroxyl group(OH) of fisetin with the carbonyl group and the phenolic group of the coformers was observed.The prepared cocrystals were further evaluated for their solubility, intrinsic dissolution and in vivo/in vitro profile.
Results: Solubility and dissolution studies of fisetin cocrystals were measured in aqueous buffer and demonstrated solubility improvement to be approximately 1.8-3.0 times higher as compared to the parent flavonoidal molecule, which subsequently led to improved pharmacokinetic parameters. Moreover, the antioxidant and antihemolytic effect of the cocrystals were found to be even high at low concentration when compared to fisetin molecule.
Conclusion:This report suggests cocrystallization as a viable approach to resolve the solubility and bioavailability issues that circumvent the use of a therapeutically potential isoflavone, fisetin. |
| Biochemical changes in sunflower plant exposed to silver nanoparticles / silver ions | Author : Ravi Gooneratne | Abstract | Full Text | Abstract :When soil is contaminated with silver (Ag), plants take up Ag and is concentrated in roots and leaves, with its effects reflected in crop health and yield. This study investigated the toxicity of silver nanoparticles (AgNPs) and silver nitrate (AgNO3 as Ag+) to sunflower seeds grown in soils amended with 150 mg/kg of Ag either as AgNPs or AgNO3. Exposure of the sunflower seeds to soils amended with Ag increased plant lipid peroxidation, activities of antioxidants enzymes (catalase, superoxide dismutase, glutathione-S-transferase), peroxidases (glutathione peroxidase pyrogallol peroxidase, guaiacol peroxidase), oxidases (ascorbate oxidase), urease, total phenolic compounds, vitamins (retinols, alpha-tocopherol and L-ascorbic acid) but inhibited chlorophyll, total carotenoids, total soluble carbohydrates, phenolic compounds and total soluble proteins. In general, AgNO3 increased the above-mentioned parameters in sunflower more than did AgNPs, except for the tested vitamins, which were more affected by AgNPs. The results showed that Ag accumulation in the root > leaf > stem and human food security risk is enhanced in sunflower seeds exposed to Ag compounds. |
| Optimization of Key Techniques for Ethanol Extraction of Camellia Seed Oil by Response Surface Experiment | Author : Yijun LIU | Abstract | Full Text | Abstract :The ethanol extraction method was utilized to extract the oil from camellia seed oil. Single-factor tests were applied to study the effects of ethanol concentration, material/solvent ratio and extraction temperature on the yield of camellia seed oil. Then, response surface methodology (RSM) was conducted to ascertain the optimum condition for oil extraction, and the fatty acid composition of the oil were analyzed. Results indicated that the optimal parameters of extraction were using ethanol concentration 100%, material/solvent ratio 1:12 and extraction temperature 90 ?. Under these conditions, the extraction yield was high up 45.36%(v/w).According to the results of GC-MS analysis, the camellia seed oil was composed of eight kinds of fatty acids. The content of 10-Octadecenoic acid was 77.57%. Calculating via the area normalization method, the unsaturated fatty acid accounted for 88.01% (w/w) of the total amount of oil. Therefore, the camellia seed oil was a kind of nutritional oil with a high development potential. |
|
|