In situ assembly of fibrinogen/hyaluronic acid hydrogel via knob-hole interaction for 3D cellular engineering

Hyaluronic acid (HA)-based hydrogels have applied widely for biomedical applications due to its biocompatibility and biodegradability. However, the use of initiators or crosslinkers during the hydrogel formation may cause cytotoxicity and thereby impair the biocompatibility. Inspired by the crosslinking mechanism of fibrin gel, a novel HA-based hydrogel was developed via the in situ supramolecular assembly based on knob-hole interactions between fibrinogen and knob-grafted HA (knob-g-HA) in this study. The knob-grafted HA was synthesized by coupling knob peptides (GPRPAAC, a mimic peptide of fibrin knob A) to HA via Michael addition. Then the translucent fibrinogen/knob-g-HA hydrogels were prepared by simply mixing the solutions of knob-g-HA and fibrinogen at the knob/hole ratio of 1.2. The rheological behaviors of the fibrinogen/knob-g-HA hydrogels with the fibrinogen concentrations of 50, 100 and 200 mg/mL were evaluated, and it was found that the dynamic storage moduli (G′) were higher than the loss moduli (G″) over the whole frequency range for all the groups. The SEM results showed that fibrinogen/knob-g-HA hydrogels presented the heterogeneous mesh-like structures which were different from the honeycomb-like structures of fibrinogen/MA-HA hydrogels. Correspondingly, a higher swelling ratio was obtained in the groups of fibrinogen/knob-g-HA hydrogel. Finally, the cytocompatibility of fibrinogen/knob-g-HA hydrogels was proved by live/dead stainings and MTT assays in the 293T cells encapsulation test. All these results highlight the biological potential of the fibrinogen/knob-g-HA hydrogels for 3D cellular engineering

Trade-Old-for-Remanufactured Closed-Loop Supply Chains with Carbon Tax and Government Subsidies

The constantly increasing CO2 emissions are threatening the environment tremendously. Facing the pressure of environmental activists and public opinion, businesses and governments are taking action to reduce carbon emissions. Among these endeavors, carbon tax and subsidy policies proposed by governments are widely adopted. Remanufacturing is believed to save manufacturing costs and reduce carbon emissions from the process of enterprise operation, and it is increasingly being accepted by enterprises. However, different consumers’ willingness to pay for remanufactured products and the durability of new products will also affect consumers’ willingness to buy remanufactured products. Therefore, considering the discrepancy between consumer willingness to pay and product durability, we established the trade-old-for-remanufactured (TOR) model for a scenario of carbon tax and government subsidies. Through the analysis of the model, we obtained the optimal pricing and production decisions of manufacturers (remanufacturers) in the case of carbon tax and government subsidies. Our results show that, when there is no carbon tax constraint, the increase in consumer willingness to pay and the adjustment in product durability can stimulate consumers to participate in TOR projects and augment enterprises’ profits. However, it can also lead to a carbon rebound that increases corporate carbon emissions. When there is a carbon tax constraint, the introduction of carbon tax contributes to a reduction in carbon emissions, while enterprises tend to lose profits. In order to achieve a “win-win„ between corporate profits and carbon emissions, we considered government subsidy policies. Our numerical examples illustrate that appropriate carbon tax and government subsidies can curb carbon emissions and also increase profits for enterprises

A near infrared spectroscopic assay for stalk soluble sugars, bagasse enzymatic saccharification and wall polymers in sweet sorghum

In this study, 123 sweet sorghum (Sorghum bicolor L.) accessions and 50 mutants were examined with diverse stalk soluble sugars, bagasse enzymatic saccharification and wall polymers, indicating the potential near infrared spectroscopy (NIRS) assay for those three important parameters. Using the calibration and validation sets and modified squares method, nine calibration optimal equations were generated with high determination coefficient on the calibration (R-2) (0.81-0.99), cross-validation (R(2)cv) (0.77-0.98), and the ratio performance deviation (RPD) (2.07-7.45), which were at first time applied by single spectra for simultaneous assay of stalk soluble sugars, bagasse hydrolyzed sugars, and three major wall polymers in bioenergy sweet sorghum. (C) 2014 Elsevier Ltd. All rights reserved

A near infrared spectroscopic assay for stalk soluble sugars, bagasse enzymatic saccharification and wall polymers in sweet sorghum

In this study, 123 sweet sorghum (Sorghum bicolor L.) accessions and 50 mutants were examined with diverse stalk soluble sugars, bagasse enzymatic saccharification and wall polymers, indicating the potential near infrared spectroscopy (NIRS) assay for those three important parameters. Using the calibration and validation sets and modified squares method, nine calibration optimal equations were generated with high determination coefficient on the calibration (R-2) (0.81-0.99), cross-validation (R(2)cv) (0.77-0.98), and the ratio performance deviation (RPD) (2.07-7.45), which were at first time applied by single spectra for simultaneous assay of stalk soluble sugars, bagasse hydrolyzed sugars, and three major wall polymers in bioenergy sweet sorghum. (C) 2014 Elsevier Ltd. All rights reserved

AtCesA8-driven OsSUS3 expression leads to largely enhanced biomass saccharification and lodging resistance by distinctively altering lignocellulose features in rice

Abstract Background Biomass recalcitrance and plant lodging are two complex traits that tightly associate with plant cell wall structure and features. Although genetic modification of plant cell walls can potentially reduce recalcitrance for enhancing biomass saccharification, it remains a challenge to maintain a normal growth with enhanced biomass yield and lodging resistance in transgenic plants. Sucrose synthase (SUS) is a key enzyme to regulate carbon partitioning by providing UDP-glucose as substrate for cellulose and other polysaccharide biosynthesis. Although SUS transgenic plants have reportedly exhibited improvement on the cellulose and starch based traits, little is yet reported about SUS impacts on both biomass saccharification and lodging resistance. In this study, we selected the transgenic rice plants that expressed OsSUS3 genes when driven by the AtCesA8 promoter specific for promoting secondary cell wall cellulose synthesis in Arabidopsis. We examined biomass saccharification and lodging resistance in the transgenic plants and detected their cell wall structures and wall polymer features. Results During two-year field experiments, the selected AtCesA8::SUS3 transgenic plants maintained a normal growth with slightly increased biomass yields. The four independent transgenic lines exhibited much higher biomass enzymatic saccharification and bioethanol production under chemical pretreatments at P < 0.01 levels, compared with the controls of rice cultivar and empty vector transgenic line. Notably, all transgenic lines showed a consistently enhanced lodging resistance with the increasing extension and pushing forces. Correlation analysis suggested that the reduced cellulose crystallinity was a major factor for largely enhanced biomass saccharification and lodging resistance in transgenic rice plants. In addition, the cell wall thickenings with the increased cellulose and hemicelluloses levels should also contribute to plant lodging resistance. Hence, this study has proposed a mechanistic model that shows how OsSUS3 regulates cellulose and hemicelluloses biosyntheses resulting in reduced cellulose crystallinity and increased wall thickness, thereby leading to large improvements of both biomass saccharification and lodging resistance in transgenic rice plants. Conclusions This study has demonstrated that the AtCesA8::SUS3 transgenic rice plants exhibited largely improved biomass saccharification and lodging resistance by reducing cellulose crystallinity and increasing cell wall thickness. It also suggests a powerful genetic approach for cell wall modification in bioenergy crops

MOESM1 of AtCesA8-driven OsSUS3 expression leads to largely enhanced biomass saccharification and lodging resistance by distinctively altering lignocellulose features in rice

Additional file 1: Figure S1. Gene expression profiling of OsSUS3 in life cycle of rice. Figure S2. Biomass enzymatic saccharification and ethanol production of the OsSUS3-transgenic rice plants. (a) Hexose yields released from enzymatic hydrolysis after the pretreatment with 1% NaOH or 1% H2SO4. (b) Bioethanol yields obtained from yeast fermentation using the sugars released from biomass enzymatic hydrolysis as performed in (a). All data are given as means ± SD. A Student’s t-test was performed between transgenic plants and ZH11 as **P < 0.01 and *P < 0.05 (n = 3)