Tongcheng Xu

Histopathological studies of sclerotia of Rhizoctonia solani parasitized by the EGFP transformant of Trichoderma virens

Aims:  The aim of the study was to investigate the antagonistic interactions of Trichoderma species against Rhizoctonia solani sclerotia by enhanced green fluorescence protein (EGFP)‐tagged transformant of Trichoderma virens TY009.

Purification and characterization of a cis-epoxysuccinic acid hydrolase from Bordetella sp. strain 1–3

Purification of a cis-epoxysuccinic acid hydrolase was achieved by ammonium sulfate precipitation, ionic exchange chromatography, hydrophobic interaction chromatography followed by size-exclusion chromatography. The enzyme was purified 177-fold with a yield of 14.4%. The apparent molecular mass of the enzyme was determined to be 33kDa under denaturing conditions. The optimum pH for enzyme activity was 7.0, and the enzyme exhibited maximum activity at about 45 degrees C in 50mM sodium phosphate buffer (pH 7.5). EDTA and o-phenanthrolin inhibited the enzyme activity remarkably, suggesting that the enzyme needs some metal cation to maintain its activity. Results of inductively coupled plasma mass spectrometry analysis indicated that the cis-epoxysuccinic acid hydrolase needs Zn(2+) as a cofactor. Eight amino acids sequenced from the N-terminal region of the cis-epoxysuccinic acid hydrolase showed the same sequence as the N-terminal region of the beta subunit of the cis-epoxysuccinic acid hydrolase obtained from Alcaligenes sp.

A novel method: ionic liquid-based ultrasound-assisted extraction of polyphenols from Chinese purple yam

Abstract Chinese purple yam is famous for therapeutic and nutritional values in lowering blood glucose, blood pressure and even preventing and treating cardiovascular diseases. However, traditional extraction techniques for the functional polyphenolic compounds mostly utilise unfriendly organic solvent and easily cause degradation of polyphenols. In this study, a novel ionic liquid-based ultrasound-assisted extraction (IL-UAE) technique was utilised to obtain polyphenols. The optimal extraction condition included: solid–liquid ratio (0.05 g/mL), ionic liquid concentration (1.05 M), extraction temperature (67°C) and ultrasonic time (37 min). The maximum free radical scavenging activity (86.21%) and total antioxidant activity (2.21 mM) were achieved and matched well with the predicted values, superior to that of the extract from regular ethanol-based UAE. IL-UAE could be a rapid and green technique for efficient extraction of polyphenols from purple yam with low solvent consumption and few structural deterioration, exhibiting application potential in food and pharmaceutical industries.

Comparative Proteomics Analysis Reveals Trans Fatty Acid Isomers Activates Different Pathways in Human Umbilical Vein Endothelial Cell.

Trans fatty acid (TFA), a group of unsaturated fats with at least one double bond in the trans configuration, plays a role in lipid metabolism, the structure of the cell membrane phospholipids, and apoptosis. Previous studies demonstrated that TFA was associated with coronary heart disease, obesity, and insulin resistance. Herein, a quantitative proteomics approach estimated the relative abundance of proteins in human umbilical vein endothelial cells treated with TFA (two different TFA structural isomers: 9t-18:1 and 9t,12t-18:2). The results revealed that 174 identified proteins were significantly altered with respect to expression. Furthermore, based on the cutoff values, 35 proteins were differentially expressed in the 9t-18:1 group as compared to the control group, 69 proteins were differentially expressed in 9t,12t-18:2 group as compared to the control group, and 120 proteins were differentially expressed in the 9t,12t-18:2 group as compared to the 9t-18:1 group. Based on the bioinformatics analysis, we found that TFA could alter the structural constitution of the cytoskeleton through protein interactions, localization into the cell membrane, and incorporation into the phospholipid of the cell. In addition, 17 differential apoptosis-related proteins, including cell division cycle 42, superoxide dismutase 1, glyoxalase I, and macrophage migration inhibitory factor were also identified. Together, these results might emphasize the need for studying TFA-induced biological processes.

Rat Small Intestinal Mucosal Epithelial Cells Absorb Dietary 1,3-Diacylglycerol Via Phosphatidic Acid Pathways.

Compared with triacylglycerol (TAG), dietary 1,3-diacylglycerol (1,3-DAG) is associated with reduced serum lipid and glucose levels. We investigated the metabolism of 1,3-DAG by assaying its intermediate metabolites during digestion and absorption in the rat small intestine. After gavage with TAG emulsion, TAG was digested mainly to 2-monoacylglycerol (2-MAG) and unesterified fatty acid (FFA) in the rat small intestinal lumen. 2-MAG was directly absorbed into the small intestinal epithelial cells and esterified to 1,2(2,3)-DAG, and further esterified to TAG. After gavage with 1,3-DAG emulsion, 1,3-DAG was digested mainly to 1(3)-MAG and FFA in the rat small intestinal lumen with subsequent significant increase of 1-MAG and 1,3-DAG concentrations in small intestinal mucosal epithelial cells, and the 2-MAG, 1,2(2,3)-DAG, and TAG concentrations in mucosal epithelial cells were not significantly different after 1,3-DAG than after TAG gavage, suggesting that the metabolic pathway of 1,3-DAG is different from that of TAG. In intestinal mucosal epithelial cells, we further assayed enzyme levels and gene expression of proteins in the phosphatidic acid (PtdOH) pathway. The glycerol kinase, phosphatidate phosphatase, and diacylglycerol acyltransferase-2 expression and the relative expression of mRNA of enzymes were significantly increased in the 1,3-DAG group compared with the TAG group, suggesting that TAG synthesis from dietary 1,3-DAG was mainly via PtdOH pathways, which may partially account for the effect of dietary DAG on postprandial serum TAG.

Effect of industrial trans -fatty acids-enriched diet on gut microbiota of C57BL/6 mice

PurposePrevious studies have shown that industrially originated trans-fatty acids (iTFAs) are associated with several chronic diseases, but the underlying mechanisms remain unknown. Because gut microbiota play a critical role in human health, diet competent induced gut microbiota dysbiosis may contributing to disease pathogenesis. Therefore, the present study examined the impact of iTFA on gut microbiota, help understanding the underling mechanism of iTFA-associated chronic diseases.MethodsForty male 8-week-old mice were divided into 4 groups and randomly assigned to diets containing soybean oil (non-iTFA) or partially hydrogenated soybean oil (iTFA). The intervention groups were: (1) low soybean oil (LS); (2) high soybean oil (HS); (3) low partially hydrogenated oil (LH) and (4) high partially hydrogenated oil (HH). The gut microbiota profiles were determined by 16S rRNA gene sequencing. Physiological parameters and the inflammatory status of the small intestine and other tissues were analyzed. Short-chain fatty acid levels in feces were measured using gas chromatography.ResultsThe intake of iTFA increased the abundance of well-documented ‘harmful’ bacteria, such as Proteobacteria and Desulfovibrionaceae (P < 0.05), whereas it decreased relative abundance of ‘beneficial’ bacteria, such as Bacteroidetes, Lachnospiraceae, Bacteroidales S24-7 (P < 0.05). Surprisingly, the intake of iTFA increased the abundance of the probiotic Lactobacillaceae (P < 0.05). Additionally, the intake of iTFA induced increase of inflammatory parameters, as well as a numerical decrease of fecal butyric acid and valeric acid.ConclusionsThis study, to our knowledge, is the first to demonstrate that the consumption of iTFA resulted in a significant dysbiosis of gut microbiota, which may contribute to the development of chronic diseases associated with iTFA.

Biological effects of trans fatty acids and their possible roles in the lipid rafts in apoptosis regulation: Modulatory mechanism of lipid rafts induced by TFA

A large number of recent studies are focused on evaluating the mechanism of action of trans fatty acids (TFAs) on the progression of apoptosis. A strong positive association has been reported between TFA and coronary heart disease (CHD), obesity and nonalcoholic steatohepatitis and so on. The present study reviewed the biological effects of trans fatty acids (TFA) and their possible roles in lipid rafts in regulating apoptosis. The following aspects of TFA were included: the research about TFA and diseases affecting serum lipid levels, inducing system inflammation and immune response, and the correlation between TFA and apoptosis. The primary purpose of the review article was to comprehensively evaluate the potential correlation between lipid rafts and apoptosis induced by different structures of TFA and provide some new research progress and future directions about it.

Efficacy of Potato Resistant Starch Prepared by Microwave–Toughening Treatment

Potato starch was treated by microwaving, toughening, and low-temperature aging to prepare resistant starch (RS). The functional properties of the resultant RS were evaluated and the effects of this microwave-toughening treatment (MTT) on the amylose content, RS content, digestive properties, pasting properties, morphological observation, crystal structure, and thermal performance of potato starch were determined. The optimal MTT parameters were microwaving at 300 W for 100 s, toughening at 55 °C for 16 h, and low-temperature aging at 4 °C for 18 h. After MTT, the amylose and RS contents of potato starch had increased from 26.08% and 11.54% to 35.06% and 27.09%, respectively. Furthermore, the pasting temperature increased from 66.8 °C to 76.36 °C, while the peak viscosity, trough viscosity, and final viscosity decreased significantly. After MTT, the potato starch surface had also changed significantly, and the crystallinity had increased from 32.43% to 51.36%. MTT starch had beneficial effects on fasting blood glucose, body weight, and organ index in mice. Furthermore, it had a protective effect on subcutaneous abdominal fat and liver tissue.

Nephroprotective effects of diacylglycerol on diabetic nephropathy in type 2 diabetic rats

Diacylglycerol (DAG) has been reported to reduce the serum lipid and glucose levels more effectively compared with triacylglycerol (TAG). The present study examined the long-term effects of dietary DAG on rats with type 2 diabetic nephropathy (DN). The type 2 DN model was established by administering a high-fat and high-calorie diet along with an intraperitoneal injection of 35 mg/kg body weight streptozocin, and the disease developed over the following 8 weeks. Sprague-Dawley rats were then randomly divided into the control, TAG, low-dose DAG (Low-DAG) and high-dose DAG (High-DAG) groups. Blood glucose (BG), lipid levels and renal function parameters were then measured. The results revealed that the body weight in the High-DAG group was significantly reduced compared with the TAG group, while there was no significant difference in the food intake between TAG and DAG groups. BG, advanced glycation end products (AGEs), TAG, low-density lipoprotein cholesterol, urine protein and urine albumin levels were significantly reduced, while high-density lipoprotein cholesterol levels were significantly increased in the two DAG groups. In addition, hematoxylin-eosin stained glomeruli presented decreased glomerular enlargement and mesangial expansion in the DAG groups. Immunohistochemical detection revealed that the levels of transforming growth factor-β1 and connective tissue growth factor in renal tissues of the DAG groups were also significantly reduced compared with the TAG group. These findings indicate that DAG oils can significantly reduce BG levels and the deposition of AGEs in renal tissue, as well as regulate the levels of transforming growth factor-β1 and connective tissue growth factor, thus delaying the progression of nephropathy.