Effects of ultrasonic treatment on the surface bacteria of Lyophyllum decastes during storage.

This study explores the relationship between the storage quality and bacterial microflora in the mushroom Lyophyllum decastes. The surface bacteria of L. decastes were separated by combining the traditional culture plate separation and 16S rRNA sequencing method, to study the effects of ultrasonic (US) treatment on the surface bacteria of L. decastes during storage. The results demonstrated that Pantoea agglomerans and Pseudomonas fluorescens were among the 15 culturable bacteria isolated with traditional plate method during storage, belonging to 2 phyla and 7 genera. US treatment could inhibit the growth and significantly increase cell membrane permeability, and contents extravasation in P. agglomerans, though its inhibitory effect on P. fluorescens was less. The 16S rRNA sequencing revealed, bacteria from 9 phyla and 35 genera were isolated, and P. fluorescens was the dominant species throughout the storage time. These results indicated that the composition of mushroom surface microflora of Control (CK) and US groups are similar, and the bacterial microflora networks analysis also showed a positive correlation. The KEGG annotation for the functional classification of the bacteria showed that a total of 328 pathways were acquired at the KEGG l3 level, and the relative abundance of membrane transport, amino acid metabolism, carbohydrate metabolism, and energy metabolism pathway was high. Moreover, the relative abundance of the surface bacteria of L. decastes also decreased. Hence, the US treatment had a better bacteriostatic effect, maintained the whiteness index and firmness, and improved the sensory quality of L. decastes during storage.

Ultrasonic treatment decreases Lyophyllum decastes fruiting body browning and affects energy metabolism.

Lyophyllum decastes is a common mushroom that is prone to browning during prolonged storage. In this study, the effects of ultrasonic treatment on metabolic gene expression, enzyme activity, and metabolic compounds related to L. decastes browning were investigated. Treatment of the fruiting body at 35 kHz and 300 W for 10 min reduced the browning index of L. decastes by 21.0 % and increased the L* value by 11.1 %. Ultrasonic treatment of the fruiting body resulted in higher levels of total phenols, flavonoids, and 9 kinds of amino acid with catalase (CAT) and peroxidase (POD) activities maintained at high levels. Higher cytochrome c oxidase (CCO), succinate dehydrogenase (SDH), phosphofructokinase (PFK), and pyruvate kinase (PK) activities may be ascribed to increased antioxidant capacity. Moreover, ultrasonication retained higher adenosine triphosphate (ATP) concentrations with an increased energy charge, while there were lower levels of adenosine diphosphate (ADP) and reduced and oxidized nicotinamide adenine dinucleotide (NADH and NAD+), respectively. Meanwhile, lower lignin contents were observed, along with retarded polyphenol oxidase (PPO) and lipoxygenase (LOX) activities. Lower PPO activity reduced the fruiting body enzymatic browning rate through decreased expression of LdPpo1, LdPpo2, and LdPpo3 during storage at 4 °C for 16 days. This activity may be used to determine the effectiveness of ultrasonication.

Anti-obesity effect of Auricularia heimuer fruiting body alcohol extraction on obese mice and crucial metabolite pathway analysis by liquid chromatography-tandem mass spectrometry.

In recent years, the increasing obese and overweight population has become a worldwide public health problem, as there is no effective medication to control obesity. Auricularia heimuer is rich in active substances that have potential biologically active functions. The anti-obesity effect and mechanism of Auricularia heimuer fruiting body alcohol extraction (AHA, 150-600 mg/kg·bw) was investigated in obese mice by assessing changes in endogenous liver metabolites using a liquid chromatography-tandem mass spectrometry approach. The aim of this study was to identify an effective food to control human obesity. AHA of 600 mg/kg·bw (HC) significantly decreased body weight and improved serum biochemistry indices. Sixty-eight liver metabolites were identified and significantly separated among the normal, high-fat diet (HFD), and HC groups. Moreover, the metabolic analysis revealed that HC significantly regulated specific metabolites in mice including amino acids, lipids, and carbohydrate compounds. Kyoto Encyclopedia of Genes and Genomes enrichment analysis revealed that HC was significantly involved in different metabolite pathways including arachidonic acid metabolism, galactose metabolism, carbohydrate digestion and absorption, linoleic acid metabolism, and starch and sucrose metabolism. Eight weeks after supplementing with HC, major metabolites in related pathways that were disrupted by an HFD were restored to normal levels, suggesting that HC had anti-obesity activity.

The MADS-box transcription factor GlMADS1 regulates secondary metabolism in Ganoderma lucidum.

MADS-box transcription factors play crucial roles in regulating development processes and biosynthesis of secondary metabolites in eukaryotes. However, the role of MADS-box transcription factors vary among fungal species, and their function remains unclear in the medicinally and economically important fungus Ganoderma lucidum. In this study, we characterized a MADS-box gene, GlMADS1, in G. lucidum. Analyses using quantitative real-time polymerase chain reaction (qRT-PCR) showed that GlMADS1 expression levels were up-regulated from the mycelia to the primordia stage. In order to further evaluate the effect of MADS-box transcription factors on secondary metabolism, we utilized RNA interference (RNAi) to silence GlMADS1 in G. lucidum. Ganoderic acid (GA) and flavonoid contents were enhanced in GlMADS1-silenced strains, suggesting that GlMADS1 negatively regulates GA and flavonoid accumulation.

The beneficial effects of Agaricus blazei Murrill on hepatic antioxidant enzymes and the pancreatic tissue recovery in streptozotocin-induced diabetic rats.

Agaricus blazei Murrill (ABM), is a medicinal mushroom, has beneficial effects on diabetes mellitus. In this study, ABM extracts (ethanol extract, EE and ethyl acetate extract, EA) were evaluated to explore the beneficial effect on hepatic antioxidant activity and recovery of the pancreatic tissue in streptozotocin-induced diabetic rats. The hepatic antioxidant activities of ABM extracts were analyzed by superoxide dismutase, catalase activity, glutathione, aspartate transaminase, and alanine transaminase. Moreover, the effects of ABM extracts on pancreatic tissue restoration were investigated by histopathological analysis. The results revealed that the EA showed a better protective effect on hepatic antioxidant activity and recovery of the impaired pancreatic tissues, compared to EE. The results suggested that ABM treatment could effectively reduce oxidative stress and contribute to pancreatic tissue recovery. Therefore, ABM could be used as a functional food to control diabetes. PRACTICAL APPLICATIONS: The research may contribute to the development of ABM as functional foods or dietary supplements for diabetes in the future.