Combined iron (III) chloride/sodium citrate with enzymatic hydrolysis for xylo-oligosaccharides and monosaccharides production from poplar.

Currently, the production of xylo-oligosaccharides (XOS) from lignocelluloses by chelating system hydrolysis has not been investigated. Herein, iron (III) chloride/sodium citrate (IC/SC) chelating system hydrolysis and xylanase hydrolysis were used to produce XOS from poplar. Then, the delignification of IC/SC-hydrolyzed poplar was performed by p-toluenesulfonic acid (p-TsOH) pretreatment to increase the accessibility of cellulase. The results demonstrated that 42.3% of XOS with an extremely low by-product (xylose/XOS = 0.11) was produced from poplar by 50 mM IC/SC hydrolysis (molar ratio of 1:1, 170 °C, 60 min) and xylanase hydrolysis. The second step IC/SC hydrolysis and xylanase hydrolysis of poplar increased the yield of XOS to 51.3%. Finally, the glucose yield of p-TsOH-pretreated poplar (60% p-TsOH, 70 °C, 30 min) was greatly increased from 37.5% to 83.8% by cellulase hydrolysis with Tween 80 addition. The novel strategy proposed in this work was feasible for XOS and monosaccharides production from poplar.

Delignification of switchgrass for xylo-oligosaccharides production using sorbic acid hydrolysis.

Organic acid as a class of hydrolysis catalysts shows great potential in the production of xylo-oligosaccharides (XOS) from lignocelluloses. However, sorbic acid (SA) hydrolysis for XOS production from lignocellulose has not been reported and it was still unclear how lignin removal affected XOS production. Herein, two factors affecting the XOS production from switchgrass by SA hydrolysis were explored: hydrolysis severity factor (Log R0) and lignin removal. Benefiting from the lignin removal (58.4%) in switchgrass, a desired XOS yield of 50.8% with low by-products was obtained from delignified switchgrass by 3% SA hydrolysis at Log R0 = 3.84. Under these conditions, 92.1% of glucose was obtained by cellulase hydrolysis with Tween 80 addition. From a mass balance perspective, 10.3 g of XOS and 23.7 g of glucose could be produced from 100 g switchgrass. This work proposed a novel strategy for XOS and monosaccharides production from delignified switchgrass.

Structural Properties and Hydrolysability of Paulownia elongate: The Effects of Pretreatment Methods Based on Acetic Acid and Its Combination with Sodium Sulfite or Sodium Sulfite.

The effects of CH3COOH and Na2SO3 pretreatment on the structural properties and hydrolyzability of fast-growing Paulownia elongate were investigated. Acetic acid increased cellulose's crystallinity and hydrolyzability when combined with alkaline sodium sulfite and sodium hydroxide. The cellulose content increased by 21%, the lignin content decreased by 6%, and the product showed better enzymatic digestibility. With a cellulase dose of 30 FPU/g DM, after 72 h hydrolysis, the hydrolysis yields of glucose and xylose were 78% and 83%, respectively, which were 51% and 69% higher than those of untreated materials. When the enzyme dosage was 20 FPU/g DM, after 72 h hydrolysis, the hydrolysis yields of glucose and xylose were 74% and 79%, respectively. The high hydrolyzability, low enzyme loading, and high hydrolysis yield demonstrate the potential of the proposed system for producing platform sugars from fast-growing Paulownia elongate.

Upstream stimulating factor1 (USF1) enhances the proliferation of glioblastoma stem cells mainly by activating the transcription of mucin13 (MUC13).

Glioblastoma is one of the most aggressive and deadly tumors among the adults. MUC13 is a membrane bound mucin and abnormal expression of MUC13 has been identified in various tumors. However, its specific role in glioblastoma has never been explored. Firstly, the expression of MUC13 was explored in glioblastoma stem cells (GSCs) and we found that MUC13 was significantly enhanced in GSCs. Overexpression of MUC13 significantly enhanced GSCs invasion and migration capacities. Further study showed that overexpression of MUC13 significantly increased the phosphorylation levels of AKT and P38. Dual luciferase reporter and ChIP assay demonstrated that USF1 could bind the promoter region of MUC13, thereby enhancing the activation of MUC13. More importantly, when MUC13 was silenced, the phosphorylation levels of AKT and P38 were suppressed even in cells transfected with ad-USF1. These data showed that USF1 prompted glioblastoma progression mainly by activating MUC13. In summary, our study first demonstrated that USF1 could activate the transcription of MUC13, thereby enhancing the proliferation and self-renewal of GSCs.

Protective roles of heat stress on the neurons in hippocampal CA1 region of mice.

The effects of heat stress on the neurons in hippocampal CA1 region of brain ischemia/reperfusion were explored. The mice were pretreated with heat stress followed by ischemia/reperfusion by clipping bilateral cervical common arteries for 7 min. Mice were divided randomly into four groups as follows: (1) normal control group; (2) heat stress pretreated subsequent to ischemia/reperfusion group (HS/IR); (3) ischemia/reperfusion group (IR); and (4) heat stress group (HS). Animals in the last three groups were subdivided into three subgroups: 1 d, 4 d, 14 d respectively. The Morris water maze was used to test the ability of learning and memorizing, Nissl staining was used to count the average number of survived neurons in hippocampal CA1 region, and immunohistochemistry combined with image analysis system to detect the changes of Microtubule associated protein 2 (MAP-2) expression. The results showed that mice in IR group exhibited increased escape latency when compared with that of normal, HS and HS/IR groups (P < 0.01), and the mice in IR group adopted an inefficient search strategy, major in circling and restricted searching manners. Nissl staining results showed a significant reduction in the number of pyramidal neurons in hippocampal CA1 regions in HS/IR and IR groups, with a decrease in IR group (P < 0.01). Compared with normal group, the expression of MAP-2 in hippocampal CA1 region obviously decreased in IR group (P < 0.05). The present results indicate that heat stress pretreatment can improve the spatial learning and memorizing function through protection to hippocampal neurons.