Microbial Transformation of Flavonoids by Isaria fumosorosea ACCC 37814

Glycosylation is an efficient strategy to modulate the solubility, stability, bioavailability and bioactivity of drug-like natural products. Biological methods, such as whole-cell biocatalyst, promise a simple but highly effective approach to glycosylate biologically active small molecules with remarkable regio- and stereo-selectivity. Herein, we use the entomopathogenic filamentous fungus Isaria fumosorosea ACCC 37814 to biotransform a panel of phenolic natural products, including flavonoids and anthraquinone, into their glycosides. Six new flavonoid (4-O-methyl)glucopyranosides are obtained and structurally characterized using high resolution mass and nuclear magnetic resonance spectroscopic techniques. These compounds further expand the structural diversity of flavonoid glycosides and may be used in biological study

Fast identification of the antibacterial in Aspergillus species

Background and Purpose: Aspergillus genus biosynthesize a large number of metabolites with wide-ranging bioactivities, but how to target the active compounds quickly and accurately? In this work, we provide a strategy to fast identify bioactive metabolites in fungi with similar morphology but different antimicrobial activities. Materials and Methods: Combined with High Performance Liquid Chromatography (HPLC) profiles and bioactivity screening of fungal extracts, three Aspergillus sp. strains YSN038, YSN052 and YSN064 were studied. The bacteria Bacillus pumilus, Bacillus subtilis, Staphylococcus aureus, Kocuria rhizophila, Escherichia coli and Ralstonia solanacearum were used for antibiotic assay. Results: Three strains showed the similar morphology, but the crude extracts of YSN038 and YSN064 displayed antibacterial activities against B. pumilus, B. subtilis, S. aureus and K. rhizophila, whereas YSN052 had not. The compound contributed to antibacterial activity in vitro was rapidly identified, isolated and characterized. Compound 3 connected with specific HPLC peak should be the antibiotic substance by analysis of HPLC profiles, and was confirmed after the following antimicrobial tests. The compound was elucidated as butyrolactone I based on nuclear magnetic resonance(NMR) and mass spectrometry (MS) data, and showed various biological activities. Conclusions: Our study has significant scope on targeting antibacterial metabolites. The described method could also be used as a rapid and cost-effective tool for screening other bioactivity products. As such, this article could offer a fast approach to isolate drug-lead compounds from microorganisms

Effect of Heat-Moisture Treatments on Digestibility and Physicochemical Property of Whole Quinoa Flour

The starch digestion processing of whole grain foods is associated with its health benefits in improving insulin resistance. This study modified the digestibility of whole quinoa flour (WQ) via heat-moisture treatment (HMT), HMT combined with pullulanase (HMT+P), HMT combined with microwave (HMT+M), and HMT combined with citric acids (HMT+A), respectively. Results showed that all the treatments significantly increased (p < 0.05) the total dietary fiber (TDF) content, amylose content, and resistant starch (RS) content, however, significantly decreased (p < 0.05) the amylopectin content and rapidly digestible starch (RDS) content of WQ. HMT+P brought the highest TDF content (15.3%), amylose content (31.24%), and RS content (15.71%), and the lowest amylopecyin content (30.02%) and RDS content (23.65%). HMT+M brought the highest slowly digestible starch (SDS) content (25.09%). The estimated glycemic index (eGI) was respectively reduced from 74.36 to 70.59, 65.87, 69.79, and 69.12 by HMT, HMT+P, HMT+M, and HMT+A. Moreover, a significant and consistent reduction in the heat enthalpy (ΔH) of WQ was observed (p < 0.05), after four treatments. All these effects were caused by changes in the starch structure, as evidenced by the observed conjunction of protein and starch by a confocal laser scanning microscope (CLSM), the decrease in relative crystallinity, and transformation of starch crystal

Development of highly glyphosate-tolerant tobacco by coexpression of glyphosate acetyltransferase gat and EPSPS G2-aroA genes

The widely used herbicide glyphosate targets 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS). Glyphosate acetyltransferase (GAT) effectively detoxifies glyphosate by N-acetylation. With the aim of identifying a new strategy for development of glyphosate-tolerant crops, the plant expression vector pG2-GAT harboring gat and G2-aroA (encoding EPSPS) has been transformed into tobacco (Nicotiana tabacum) to develop novel plants with higher tolerance to glyphosate. Results from Southern and Western blotting analyses indicated that the target genes were integrated into tobacco chromosomes and expressed effectively at the protein level. Glyphosate tolerance was compared among transgenic tobacco plants containing gat, G2-aroA, or both genes. Plants containing both gat and G2-aroA genes were the most glyphosate-tolerant. This study has shown that a combination of different strategies may result in higher tolerance in transgenic crops, providing a new approach for development of glyphosate-tolerant crops

HPAEC analyses of the hydrolysis products of cellooligosaccharide.

<p>1, cellotriose; 2, cellotetraose; 3, cellopentaose; 4, cellohexaose; 5, cellooligosaccharide standards: G1, glucose; G2, cellobiose; G3, cellotriose; G4, cellotetraose; G5, cellopentaose; G6, cellohexaose.</p

Characterization of purified recombinant Cel7A.

<p>(<b>A)</b> Effect of pH on enzyme activity assayed at 60°C. (<b>B)</b> pH stability. The enzyme activity was assayed after 1-h incubation at 37°C and different pH values. (<b>C)</b> Effect of temperature on enzyme activity at optimal pH. (<b>D)</b> Thermostability assay at 60°C and 70°C. Each value in the panel represents the means ± SD (<i>n</i> = 3).</p

The effect of metal cations and reagents (5 mM) on the activity of recombinant Egl7A.

<p>^a Values represent the mean ± SD (n = 3) relative to untreated control sample</p><p>The effect of metal cations and reagents (5 mM) on the activity of recombinant Egl7A.</p

A Novel GH7 Endo-β-1,4-Glucanase from <i>Neosartorya fischeri</i> P1 with Good Thermostability, Broad Substrate Specificity and Potential Application in the Brewing Industry

<div><p>An endo-β-1,4-glucanase gene, <i>cel7A</i>, was cloned from the thermophilic cellulase-producing fungus <i>Neosartorya fischeri</i> P1 and expressed in <i>Pichia pastoris</i>. The 1,410-bp full-length gene encodes a polypeptide of 469 amino acids consisting of a putative signal peptide at residues 1–20, a catalytic domain of glycoside hydrolase family 7 (GH7), a short Thr/Ser-rich linker and a family 1 carbohydrate-binding module (CBM 1). The purified recombinant Cel7A had pH and temperature optima of pH 5.0 and 60°C, respectively, and showed broad pH adaptability (pH 3.0–6.0) and excellent stability at pH3.0–8.0 and 60°C. Belonging to the group of nonspecific endoglucanases, Cel7A exhibited the highest activity on barley β-glucan (2020 ± 9 U mg^–1), moderate on lichenan and CMC-Na, and weak on laminarin, locust bean galactomannan, Avicel, and filter paper. Under simulated mashing conditions, addition of Cel7A (99 μg) reduced the mash viscosity by 9.1% and filtration time by 24.6%. These favorable enzymatic properties make Cel7A as a good candidate for applications in the brewing industry.</p></div

HPAEC analyses of the hydrolysis products of barley β-glucan and CMC-Na.

<p>1, The hydrolysis products of CMC-Na; 2, The hydrolysis products of barley β-glucan; 3, the cellooligosaccharide standards: G1, glucose; G2, cellobiose; G3, cellotriose; G4, cellotetraose; G5, cellopentaose; G6, cellohexaose.</p

SDS-PAGE analysis of purified recombinant Cel7A.

<p>Lanes: M, the molecular mass standards; 1, the deglycosylated Cel7A with Endo H treatment; 2, the purified recombinant Cel7A.</p