Shaoxing rice wine is one of the most typical representatives of Chinese rice wine. It is brewed under non-sterile condition with various microorganism growing at the same time and forms a special flavor. The aims of this study was to monitor the bacterial succession by MiSeq pyrosequencing and the volatile compound dynamics by HS-SPME/GC–MS during brewing process. Moreover, the volatile compounds and bacterial community were analyzed by partial least squares regression to evaluate the effect of bacteria on volatile compounds formation. The results showed that there were ten dominating genera during Shaoxing rice wine fermentation process. Ten genera, Bacillus, Leuconostoc, Lactococcus, Weissella, Thermoactinomyces, Pseudomonas, Saccharopolyspora, Staphylococcus, Enterobacter and Lactobacillus, were identified as the main bacteria. The Bacillus and Lactobacillus dominated the Chinese rice wine ecosystems. In addition, a total of 64 volatile compounds were identified, mainly esters, alcohols, carbonyl compound and phenols. Pseudomonas were involved in synthesis of a wide variety of volatile compounds. Thermoactinomyces, Bacillus and Lactococcus also played critical roles in the formation of volatile compounds.
Some studies have shown that stachyose, as prebiotics, can prevent indirectly colon cancer cell growth by promoting the proliferation of probiotics or producing beneficial materials in the intestine. However, its direct inhibitory effects on cancer cells are still unclear. Thus, this study aims to investigate the direct inhibitory effect of stachyose on human colon cancer cells and determine the molecular mechanism underlying this effect. The MTT assay was used to assess the inhibitory effect of stachyose on Caco-2 cells. Apoptosis and mitochondrial membrane potential (ΔΨm) measurements were analyzed using flow cytometry. The activities and mRNA expressions of caspases 3 and 9 were determined using caspase assay kits and quantitative real-time polymerase chain reaction. The apoptotic protein expressions of Bcl-2, Bax, and cytochrome C (Cyt C) were detected through western blotting. Results showed that stachyose inhibits Caco-2 cell proliferation and induces apoptosis in a dose-dependent manner. After pretreatment with 0.4, 0.8, 1.6 and 3.2 mg mL(-1) stachyose, cell inhibitory rates of 15.31% ± 3.20%, 28.45% ± 2.10%, 40.23% ± 5.70%, and 55.67% ± 4.50% were respectively obtained. Compared with the control, decreases in ΔΨm, increases in caspase 3 and 9 activities and mRNA expressions, down-regulation of Bcl-2 protein expression, up-regulation of the Bax protein and Cyt C release of Caco-2 cells were clearly observed upon exposure to different stachyose concentrations. The inhibitory mechanism of stachyose on Caco-2 cells involves the caspase-dependent mitochondrial apoptosis pathway.
In this study, a Ganoderma lucidum polysaccharide GLP-1-1 was isolated from a culture broth with Mw of 22014 Da. Monosaccharide contained glucose, mannose, and galactose with mole percentages of 92.33%, 7.55%, and 0.22%, respectively. Moreover, FTIR and methylation analysis were conducted to characterize the structural properties of GLP-1-1. The results of antioxidant activity analysis showed that GLP-1-1 had a great DPPH and ABTS radical scavenging activity. Meanwhile, GLP-1-1 also exhibited anti-tumor activity to A431 and MDA-MB-231 cells, and inhibitory rates were dose-dependent. During culturing with GLP-1-1, the G1/G0 cell percentage of A431 cells was increased from 48.64% to 84.52%, and the G1/G0 cell percentage of MDA-MB-231 cells was increased from 57.14% to 73.48%. Therefore, the anti-tumor activity of GLP-1-1 may be caused by inducing the G1/G0 arrest of tumor cells.
Polyunsaturated fatty acids (PUFAs) are essential lipids for cell function, normal growth, and development, serving as key structural components of biological membranes and modulating critical signal transduction events. Omega-3 (n-3) long chain PUFAs (LC-PUFAs) such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) have been shown to protect against inflammatory diseases and enhance brain development and function. This had led to a marked increase in demand for fish and fish oils in human diets, supplements, and aquaculture and created a need for new, sustainable n-3 LC-PUFA sources. We have studied for the first time homogenous preparations of the membrane-type ω6 and ω3 fatty acid desaturases from the fungus Mortierella alpina, as a model system to produce PUFAs. These desaturases possess a di-iron metal center and are selective for 18:1 n-9 and 18:2 n-6 acyl-CoA substrates, respectively. Sequence alignments and membrane topology predictions support that these enzymes have unique cap regions that may include the rearrangement and repositioning of the active site, especially when compared to the mammalian stearoyl-coenzyme A desaturase-1 (SCD1) and the related sphingolipid α-hydroxylase (Scs7p) that act upon different substrates.
Monacolin K (MK) is a secondary metabolite synthesized by polyketide synthases ofMonascus spp. In this study, the combined supplementation of three medicines, including Citri Reticulatae Pericarpium (CRP), Fructus crataegi (FC), and Radix Angelicae Dahuricae (RAD), were mixed with nonglutinous rice and were optimized by response surface methodology to enhance the production of MK in fermented red mold rice (RMR). Under the optimum condition, MK production achieved 3.60 mg/g, which was 41.18% higher than RMR without medicines. The improved MK production was mainly caused by the up-regulated transcription level of mokA, mokB, mokF, mokH, mokI, and mplaeA. Meanwhile, the inhibitory effect of Poria cocos (PC) on MK production (only 0.436 mg/g) was caused by significantly down-regulated transcription of six tested genes. Therefore, this study is beneficial for better understanding of the possible mechanism of enhanced MK production by optimization of fermentation conditions.
K E Y W O R D SChinese medicine, monacolin K, Monascus ruber, red mold rice, response surface methodology | 2135 PENG Et al.
Chinese rice wine sludge (CRWS), analogous to beer yeast sludge, is the filter cake remaining after squeezing the fermentation mash of Chinese rice wine. CRWS contains high levels of protein (44.74%), nonstructural carbohydrates (37.33%), crude fiber (13.5%), and essential amino acids, which could enhance the trophic value of Chinese steamed buns. In our research, the microbiota of CRWS (mainly Saccharomyces cerevisiae and Lactobacillus sp.) was analyzed at the species level by single‐molecule real‐time DNA sequencing technology. Interestingly, the microbiota of CRWS was similar to that of the starter dough typically used to prepare Chinese steamed buns. Incorporation of CRWS significantly influenced the pasting properties and farinograph characteristics of the dough, which control the texture of the Chinese steamed buns, and supplementation with 5∼30% CRWS caused the properties of the resulting buns to be more similar to those of northern‐style steamed buns. CRWS addition also significantly enhanced the content of aroma compounds in the Chinese steamed buns.
Practical applications
In China, approximately three million tons of CRWS is produced per year, and the reutilization of CRWS is a challenge faced by the Chinese rice wine industry. Meanwhile, Chinese steamed buns prepared with CRWS are becoming increasingly popular, and CRWS has been used in the preparation of homemade Chinese steamed buns. However, the use of CRWS in the industrial production of Chinese steamed buns has not yet been developed. The productive use of CRWS could have substantial economic benefits. In this study, the effect of CRWS incorporation on Chinese steamed buns is reported for the first time. The results showed that CRWS improved the quality of Chinese steamed buns. The results of this study suggest a simple and convenient method for incorporating CRWS into the industrial production of northern‐style Chinese steamed buns.
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