Pip5k1γ promotes anabolism of nucleus pulposus cells and intervertebral disc homeostasis by activating CaMKII-Ampk pathway in aged mice.

Degenerative disc disease (DDD) represents a significant global health challenge, yet its underlying molecular mechanisms remain elusive. This study aimed to investigate the role of type 1 phosphatidylinositol 4-phosphate 5-kinase (Pip5k1) in intervertebral disc (IVD) homeostasis and disease. All three Pip5k1 isoforms, namely Pip5k1α, Pip5k1ß, and Pip5k1γ, were detectable in mouse and human IVD tissues, with Pip5k1γ displaying a highest expression in nucleus pulposus (NP) cells. The expression of Pip5k1γ was significantly down-regulated in the NP cells of aged mice and patients with severe DDD. To determine whether Pip5k1γ expression is required for disc homeostasis, we generated a Pip5k1γfl/fl; AggrecanCreERT2 mouse model for the conditional knockout of the Pip5k1γ gene in aggrecan-expressing IVD cells. Our findings revealed that the conditional deletion of Pip5k1γ did not affect the disc structure or cellular composition in 5-month-old adult mice. However, in aged (15-month-old) mice, this deletion led to several severe degenerative disc defects, including decreased NP cellularity, spontaneous fibrosis and cleft formation, and a loss of the boundary between NP and annulus fibrosus. At the molecular level, the absence of Pip5k1γ reduced the anabolism of NP cells without markedly affecting their catabolic or anti-catabolic activities. Moreover, the loss of Pip5k1γ significantly dampened the activation of the protective Ampk pathway in NP cells, thereby accelerating NP cell senescence. Notably, Pip5k1γ deficiency blunted the effectiveness of metformin, a potent Ampk activator, in activating the Ampk pathway and mitigating lumbar spine instability (LSI)-induced disc lesions in mice. Overall, our study unveils a novel role for Pip5k1γ in promoting anabolism and maintaining disc homeostasis, suggesting it as a potential therapeutic target for DDD.

Preparation and characterization of cellulose-chitosan/ß-FeOOH composite hydrogels for adsorption and photocatalytic degradation of methyl orange.

Biopolymer-based hydrogels have received great attention in wastewater treatment due to their excellent properties, e.g., high adsorption capacity, fast kinetics, reusability and ease of operation. In the present work, cellulose-chitosan/ß-FeOOH composite hydrogels were prepared via co-dissolution and regeneration process as well as hydrothermal in situ synthesis of ß-FeOOH. Effect of ß-FeOOH loading on the properties of the composite hydrogels and the removal efficiency of methyl orange (MO) was investigated. Results showed that ß-FeOOH was uniformly loaded onto the hydrogel framework, and the nanoporous structure of composite hydrogels could increase not only the effective contact area between ß-FeOOH and the pollutants but also the active sites. Moreover, the increased ß-FeOOH loading led to the enhanced MO removal rate under light conditions. When the loading time was extended from 6 h to 9 h, the MO removal rate increased by 21%, which can be mainly due to the photocatalytic degradation. In addition, MO removal rate reached 97.75% within 40 min under optimal conditions and attained 80.81% after five repetitions. The trapping experiment and EPR results indicated that the main active species were hydrogel radicals and holes. Consequently, this work provides an effective preparation approach for cellulose-chitosan/ß-FeOOH composite hydrogel with high adsorption and photocatalytic degradation, which would hold great promise for wastewater treatment applications.

Synthesis and characterization of polyaniline-based composites using cellulose nanocrystals as biological templates.

Polyaniline (PANI) is considered as an ideal electrode material due to its remarkable Faradaic activity, exceptional conductivity, and ease of processing. However, the agglomeration and poor cycling stability of PANI largely limit its practical utilization in energy storage devices. To address these challenges, PANI was synthesized via a facile one-pot, two-step process using cellulose nanocrystals (CNCs) as bio-templates in this work. Zeta potential and particle size measurements revealed that the CNC template could impart improved dispersion stability to the synthesized PANI, which exhibited a decrease in average particle size from 1100 nm to 300 nm as a function of 10 % CNCs. Furthermore, the effect of CNC loadings on the performance of PANI was systematically investigated. The results showed that the specific capacitance of PANI/CNC increased from 102.52 F·g-1 to 138.12 F·g-1 with the CNC loading increase from 0 to 10 wt%. Particularly, the PANI/CNC composite film with a 1:9 ratio (C-P-10 %) demonstrated a capacity retention of 84.45 % after 6000 cycles and an outstanding conductivity of 526 S·m-1. This work generally offers an effective solution for the preparation of high-performance PANI-based composites, which might hold great promise in energy storage device applications.

Facile dissolution of cellulose by superbase-derived ionic liquid using organic solvents as co-solvents at mild temperatures.

Dissolving cellulose at low temperatures is a key step in its efficient utilization as a renewable resource to produce high-value-added platform chemicals and high-performance materials. Here, the potential of four aprotic organic solvents was investigated for use as co-solvents with a sustainable DBU-derived ionic liquid (SIL) for the low-temperature dissolution and regeneration of cellulose. Combined experiments, density functional theory calculations, and molecular dynamic simulations were performed. The type and amount of co-solvent were found to have a significant impact on the solubility of cellulose, the dissolution process, and the structure of regenerated cellulose. The addition of organic solvents can significantly reduce the cellulose dissolution temperature and increase the solubility. Among the solvents assessed, 40 wt% DMSO exhibited the most effective synergistic interaction with SIL, where the solubility of cellulose was 14.6 wt% at 75 °C. Subsequently, the effects of the different types and amounts of co-solvents on the microscopic morphology and chemical structure of regenerated cellulose were thoroughly explored. The results showed that different types of organic solvents had different effects on the microstructure of regenerated cellulose. The results may guide the manufacturing specifications of high-performance regenerated fiber materials.

Cellulose dissolution and regeneration behavior via DBU-levulinic acid solvents.

Most organic solvents are unable to dissolve carbohydrates due to the lack of hydrogen bonding ability. The development of solvent systems for dissolving cellulose is of great importance for its utilization and conversion. In this study, four new cellulose solvents were designed using inexpensive levulinic acid (LevA) and 1,8-diazabicyclo [5,4,0] undec-7-ene (DBU) as raw materials. The results showed that the prepared DBU-LevA-2 solvent was able to dissolve up to 7 wt% of bamboo cellulose (DP = 860) and 16 wt% of microcrystalline cellulose (DP = 280) at 100 °C and regenerated without derivatization. Also, the molar ratio of each component of this solvent has a significant effect on the dissolution properties of cellulose. The regenerated cellulose had the typical crystalline characteristics of cellulose II. Subsequently, the interactions and microscopic behaviors of solvent and cellulose during the dissolution process were thoroughly investigated by using NMR spectroscopy combined with density functional theory. The systematic study showed that the hydrogen bond-forming ability provided by DBU, a superbase, plays an indispensable role in the overall solvent system.

Synthesis of bifunctional thermal response promoters for improved high-solids enzymatic hydrolysis of corncob residues.

The enzymatic hydrolysis cost of lignocellulose can be reduced by improving enzymatic hydrolysis and recycling cellulase by adding additives. A series of copolymers P(SSS-co-SPE) (PSSPs) were synthesized using sodium p-styrene sulfonate (SSS) and sulfobetaine (SPE) as monomers. PSSP exhibited upper critical solution temperature response. PSSP with high molar ratio of SSS displayed more significant improved hydrolysis performance. When 10.0 g/L PSSP5 was added to the hydrolysis system of corncob residues, and substrate enzymatic digestibility at 72 h (SED@72 h) increased by 1.4 times. PSSP with high molecular weight and moderate molar ratio of SSS, had significant temperature response, enhanced hydrolysis, and recovering cellulase properties. For high-solids hydrolysis of corncob residues, SED@48 h increased by 1.2 times with adding 4.0 g/L of PSSP3. Meanwhile, 50% of cellulase amount was saved at the room temperature. This work provides a new idea for reducing the hydrolysis cost of lignocellulose-based sugar platform technology.

Lignin-grafted quaternary ammonium phosphate with temperature and pH responsive behavior for improved enzymatic hydrolysis and cellulase recovery.

The cost of lignocellulosic enzymatic hydrolysis was reduced by enhancing enzymatic hydrolysis and recycling cellulase. Lignin-grafted quaternary ammonium phosphate (LQAP) with sensitive temperature and pH response, was obtained by grafting quaternary ammonium phosphate (QAP) onto enzymatic hydrolysis lignin (EHL). LQAP dissolved under the hydrolysis condition (pH 5.0, 50 °C) and enhanced the hydrolysis. After hydrolysis, LQAP and cellulase co-precipitated by the hydrophobic binding and electrostatic attraction, when lowering pH to 3.2, and cooling to 25 °C. LQAP had significant performances of pH-UCST response, enzymatic hydrolysis enhancement and cellulase recovery at the same time. When 3.0 g/L LQAP-100 was added to the system of corncob residue, SED@48 h increased from 62.6 % to 84.4 %, and 50 % of amount of cellulase was saved. Precipitation of LQAP at low temperature was mainly attributed to the salt formation of positive and negative ions in QAP; LQAP enhanced the hydrolysis for its ability to decrease the ineffective adsorption of cellulase by forming a hydration film on lignin and through the electrostatic repulsion. In this work, a lignin amphoteric surfactant with temperature response, was used to enhance hydrolysis and recover cellulase. This work will provide a new idea for reducing the cost of lignocellulose-based sugar platform technology, and high-value utilization of industrial lignin.

Synthesis of temperature and pH responsive lignin-grafted sulfobetaine for efficiently recycling cellulase.

Recycling cellulase can reduce the cost of lignocellulosic enzymatic hydrolysis. Here, a lignin-grafted sulfobetaine (LSB) was first synthesized by grafting sulfobetaine (SB) on enzymatic hydrolysis lignin (EHL). LSB had a sensitive response of pH and temperature. LSB dissolved under the conditions of lignocellulosic enzymatic hydrolysis (pH 5.0, 50 °C). After hydrolysis, LSB co-precipitated with cellulase when lowering pH of the hydrolysate to 4.0 and cooling to 25 °C. When 3.0 g/L LSB-100 was added to the hydrolysis system of corncob residue (CCR), 70 % of amount of cellulase was saved. LSB had a remarkable response and stronger cellulase recovery capacity. This was attributed that carboxylate radical in LSB was protonated, and positive and negative ions of SB associated to form salt at 25 °C. This work provides a new idea for reducing the cost for preparing fermentable sugars from lignocellulose, and increasing the added value of EHL.

Using highly recyclable sodium caseinate to enhance lignocellulosic hydrolysis and cellulase recovery.

Most additives that capable of enhancing enzymatic hydrolysis of lignocellulose are petroleum-based, which are not easy to recycle with poor biodegradability. In this work, highly recyclable and biodegradable sodium caseinate (SC) was used to enhance lignocellulosic hydrolysis with improved cellulase recyclability. When the pH decreased from 5.5 to 4.8, more than 96% SC could be precipitated from the solution and recovered. Adding SC increased enzymatic digestibility of dilute acid pretreated eucalyptus (Eu-DA) from 39.5% to 78.2% under Eu-DA loading of 10 wt% and pH = 5.5, and increase cellulase content in 72 h hydrolysate from only 15.2% of the original to 60.0%, which facilitated the recovery of cellulases through re-adsorption by fresh substrates. With multiple cycles of re-adsorption, application of SC not only increased the sugar yield of Eu-DA by 95.5%, but also reduced cellulase loading by 40%.

Crucial sites and environmental variables for wintering migratory waterbird population distributions in the natural wetlands in East Dongting Lake, China.

Dongting Lake is the second largest freshwater lake in China and is one of the globally important wintering sites for migratory waterbirds in the East Asian-Australasian Flyway. Crucial sites and environmental variables for wintering migratory waterbirds are of great concern in the Dongting Lake wetlands. In this research, based on annual (2003/2004-2016/2017) waterbird and habitat census data, we recognized the crucial sites for waterbirds during wintering seasons by comparing the difference of waterbird populations at the community, foraging guild and species levels in different natural wetlands within East Dongting Lake, and then identified the crucial environmental variables affecting waterbird distributions by analyzing the relationship between waterbird populations and the environmental variables, including vegetation area, mudflat area, water area with the depth of 0-20 cm, water area with the depth of 20-50 cm, water area with the depth of 50-100 cm, water area with the depth >100 cm, growth status of vegetation (Min, Mean and Max NDVI), and the human disturbance. Results indicated that five natural wetlands, i.e., Daxiaoxi, Chunfeng, Baihu lakes, Dingzi dyke and Tanjiaweizi, were recognized as the crucial wintering sites for migratory waterbirds in the East Dongting Lake. Among the ten selected environmental variables, water areas with the depth of 0-20 cm, 20-50 cm and >100 cm, human disturbance, Min and Mean NDVIs were identified as the crucial environmental variables overall. Waterbirds at different levels exhibited significant linear relationship with certain environmental variables, with the exception of Bean goose and Lesser White-fronted goose at the species level, which showed Gaussian distribution with changes in mean NDVI. The crucial environmental variables appeared to be foraging guild- and species-specific. These findings provide significant information for managers to understand the differences of wetlands and waterbird populations within East Dongting Lake, and to make more targeted conservation efforts.