Sustainable bio-based phenol-formaldehyde resoles using hydrolytically depolymerized kraft lignin

© 2017 by the authors. In this study bio-based bio-phenol-formaldehyde (BPF) resoles were prepared using hydrolytically depolymerized Kraft lignin (DKL) as bio-phenol to partially substitute phenol. The effects of phenol substitution ratio, weight-average molecular weight (Mw) of DKL and formaldehyde-to-phenol (F/P) ratio were also investigated to find the optimum curing temperature for BPF resoles. The results indicated that DKL with Mw ∼1200 g/mol provides a curing temperature of less than 180°C for any substitution level, provided that F/P ratios are controlled. Incorporation of lignin reduced the curing temperature of the resin, however, higher Mw DKL negatively affected the curing process. For any level of lignin Mw, the curing temperature was found to increase with lower F/P ratios at lower phenol substitution levels. At 25% and 50% phenol substitution, increasing the F/P ratio allows for synthesis of resoles with lower curing temperatures. Increasing the phenol substitution from 50% to 75% allows for a broader range of lignin Mw to attain low curing temperatures

Redox Regulation in Cancer Stem Cells

Reactive oxygen species (ROS) and ROS-dependent (redox regulation) signaling pathways and transcriptional activities are thought to be critical in stem cell self-renewal and differentiation during growth and organogenesis. Aberrant ROS burst and dysregulation of those ROS-dependent cellular processes are strongly associated with human diseases including many cancers. ROS levels are elevated in cancer cells partially due to their higher metabolism rate. In the past 15 years, the concept of cancer stem cells (CSCs) has been gaining ground as the subpopulation of cancer cells with stem cell-like properties and characteristics have been identified in various cancers. CSCs possess low levels of ROS and are responsible for cancer recurrence after chemotherapy or radiotherapy. Unfortunately, how CSCs control ROS production and scavenging and how ROS-dependent signaling pathways contribute to CSCs function remain poorly understood. This review focuses on the role of redox balance, especially in ROS-dependent cellular processes in cancer stem cells (CSCs). We updated recent advances in our understanding of ROS generation and elimination in CSCs and their effects on CSC self-renewal and differentiation through modulating signaling pathways and transcriptional activities. The review concludes that targeting CSCs by manipulating ROS metabolism/dependent pathways may be an effective approach for improving cancer treatment

High-Salt Diet Has a Certain Impact on Protein Digestion and Gut Microbiota: A Sequencing and Proteome Combined Study

High-salt diet has been considered to cause health problems, but it is still less known how high-salt diet affects gut microbiota, protein digestion, and passage in the digestive tract. In this study, C57BL/6J mice were fed low- or high-salt diets (0.25 vs. 3.15% NaCl) for 8 weeks, and then gut contents and feces were collected. Fecal microbiota was identified by sequencing the V4 region of 16S ribosomal RNA gene. Proteins and digested products of duodenal, jejunal, cecal, and colonic contents were identified by LC-MS-MS. The results indicated that the high-salt diet increased Firmicutes/Bacteroidetes ratio, the abundances of genera Lachnospiraceae and Ruminococcus (P < 0.05), but decreased the abundance of Lactobacillus (P < 0.05). LC-MS-MS revealed a dynamic change of proteins from the diet, host, and gut microbiota alongside the digestive tract. For dietary proteins, high-salt diet seemed not influence its protein digestion and absorption. For host proteins, 20 proteins of lower abundance were identified in the high-salt diet group in duodenal contents, which were involved in digestive enzymes and pancreatic secretion. However, no significant differentially expressed proteins were detected in jejunal, cecal, and colonic contents. For bacterial proteins, proteins secreted by gut microbiota were involved in energy metabolism, sodium transport, and protein folding. Five proteins (cytidylate kinase, trigger factor, 6-phosphogluconate dehydrogenase, transporter, and undecaprenyl-diphosphatase) had a higher abundance in the high-salt diet group than those in the low-salt group, while two proteins (acetylglutamate kinase and PBSX phage manganese-containing catalase) were over-expressed in the low-salt diet group than in the high-salt group. Consequently, high-salt diet may alter the composition of gut microbiota and has a certain impact on protein digestion

Catalytic isomerization of glucose to fructose using heterogeneous solid Base catalysts in a continuous-flow tubular reactor: Catalyst screening study

The final publication is available at Elsevier via https://dx.doi.org/10.1016/j.cattod.2018.03.056 © 2019. This manuscript version is made available under the CC-BY-NC-ND 4.0 license https://creativecommons.org/licenses/by-nc-nd/4.0/Isomerization reactions of glucose into fructose in aqueous media were studied in a continuous-flow tubular reactor using different heterogeneous solid base catalysts, including calcined-rehydrated hydrotalcite, magnesium oxide, Amberlyst A21 ion exchange resin and two commercial hydrotalcite catalysts. The catalysts were characterized and their activities for glucose isomerization were compared. The most active catalyst was found to be magnesium oxide, which showed the highest glucose conversion (36.3%) and highest fructose yield (22.8%) at 100 °C. Among all catalysts, the calcined-rehydrated hydrotalcite showed the highest selectivity towards fructose, reaching 78% at 100 °C. It was also found that increasing the reaction temperature had positive effects on glucose conversion and fructose yield for both activated hydrotalcite and MgO catalysts. The fructose yield at 120 °C attained 19.5% and 25.1% with the activated hydrotalcite and MgO catalysts, respectively. The catalytic activity of hydrotalcite calcined at 450 °C for glucose isomerization reaction was found to be greater that calcined at 350 °C. The hyrdotalcite and magnesium oxide catalysts were observed to be stable in the four hours of continuous tests on stream. TGA analyses of the used catalysts proved the formation of undesired insoluble by-products, mainly humins, on the surface of the used catalysts.NSERC Discovery Program, Ontario governmen

Beef, Casein, and Soy Proteins Differentially Affect Lipid Metabolism, Triglycerides Accumulation and Gut Microbiota of High-Fat Diet-Fed C57BL/6J Mice

Consumption of dietary protein at recommended levels is considered a potential strategy to promote satiety and weight management, but how protein from different dietary sources effect the obesity development, lipid metabolism, and gut microbiota is not known. This study focused on the effects of beef, casein, and soy protein diet on lipid metabolism, triglycerides accumulation, and microbial diversity in colon of C57BL/6J mice, which were given either low-fat diets (LFD, 12% Kcal) or high-fat diets (HFD, 60% Kcal) for 12 weeks. Body and liver weight increased significantly in mice fed a beef protein HFD (HFB), whereas reduced cumulative energy intake was seen in a soy protein HFD (HFS) group. HFB-fed mice showed signs of impaired glucose metabolism and insulin resistance along with a significant elevation in the concentration of triglycerides, LDL-cholesterol, total cholesterol, IL1β, TNF-α, IL-6, and leptin in serum. HFB also enhanced lipid accumulation in liver with increased activity of genes important for lipogenesis and hepatic cholesterol metabolism. A 16S rRNA gene sequencing indicated that HFD, regardless of proteins, significantly enhanced the ratio of Firmicutes to Bacteroidetes in colonic microbiota. However, HFB not only reduced the abundance of Akkermansia, compared with LFD independent of proteins, but also decreased the abundance of butyrate-producing bacteria such as Anaerotruncus, Butyricicoccus, and Lactobacillus (P < 0.05) compared with HFS and HFC. In conclusion, consumption of HFB does not only affect the gut microbiota composition but also increases the problems related to metabolic syndromes like dyslipidemia, hypercholesterolemia, and triglycerides accumulation in liver, which lead to systemic inflammation and its associated comorbidities, for example, impaired glucose metabolism and insulin resistance

Low-temperature thermal pre-treatment of municipal wastewater sludge: process optimization and effects on solubilization and anaerobic degradation

The present study examines the relationship between the degree of solubilization and biodegradability of wastewater sludge in anaerobic digestion as a result of low-temperature thermal pre-treatment. The main effect of thermal pre-treatment is the disintegration of cell membranes and thus solubilization of organic compounds. There is an established correlation between chemical oxygen demand (COD) solubilization and temperature of thermal pre-treatment, but results of thermal pre-treatment in terms of biodegradability are not well understood. Aiming to determine the impact of low temperature treatments on biogas production, the thermal pre-treatment process was first optimized based on an experimental design study on waste activated sludge in batch mode. The optimum temperature, reaction time and pH of the process were determined to be 80\ua0°C, 5\ua0h and pH 10, respectively. All three factors had a strong individual effect (p\ua

Dietary protein sources differentially affect the growth of Akkermansia muciniphila and maintenance of the gut mucus barrier in mice

Scope: The gut microbiota plays an essential role in linking diet to host health. The specific role of different dietary proteins on the gut microbiota and health is less understood. Here we investigated the impact of proteins derived from chicken and soy on the gut microbiota and host gut barrier in C57BL/6 mice. Methods and results: Specific-pathogen-free and germ-free mice were assigned to either a chicken or a soy protein-based diet for 4 weeks. Compared with a chicken protein-based diet, intake of a soy protein-based diet reduced the abundance of A. muciniphila and the number of goblet cells, lowered the level of Muc2 mRNA, and decreased the thickness of the mucus layer in the colon of specific-pathogen-free mice. In germ-free mice colonization with A. muciniphila combined with intake of a chicken protein-based diet resulted in a higher expression of the Muc2 mRNA in colon, and surprisingly, an increased potential for oxidative phosphorylation in A. muciniphila compared with colonized mice fed a soy protein-based diet. Conclusion: These findings suggest possible mutually beneficial interactions between the growth and function of A. muciniphila and host mucus barrier in response to intake of a chicken protein-based diet contrasting the intake of a soy protein-based diet