Development of an enzymatic cascade to systematically utilize lignocellulosic monosaccharide.

BACKGROUND: The fermentation valorization of two main lignocellulosic monosaccharides, glucose and xylose, is extensively developed; however, it is restricted by limited yield and process complexity. An in vitro enzymatic cascade reaction can be an alternative approach. RESULTS: In this study, a three-stage, five-enzyme cascade was developed to convert pretreated biomass to valuable chemicals. First, a ribose-5-phosphate isomerase B mutant isomerized xylose to d-xylulose with high substrate specificity, and a d-arabinose dehydrogenase continued to reduce d-xylulose to d-arabitol. Simultaneously, glucose was utilized for the coenzyme regeneration catalyzed by a glucose dehydrogenase, generating useful gluconic acid and achieving 73% of total conversion rate after 36 h. Then, six kinds of pretreated biomass lignocellulose were hydrolyzed by cellulase and hemicellulase, and corn cob was identified as the initial substrate for providing the highest monosaccharide content. A 65% conversion rate of the lignocellulosic xylose was obtained after 24 h. CONCLUSIONS: This study presents a proof of concept to convert main lignocellulosic monosaccharides systematically by an enzymatic cascade at stoichiometric ratio. © 2022 Society of Chemical Industry.

A diagnostic classification model of college instructors' value beliefs towards open educational resources.

Open educational resources (OER) can be cost-effective alternatives to traditional textbooks for higher education faculty to decrease student spending on textbooks. To further advocate college instructors' use of OER, understanding their value belief towards integrating OER in teaching is necessary but currently absent. This study thus analyzed 513 college instructors' value beliefs about using OER in college teaching by applying a psychometric model known as diagnostic classification models (DCMs). The findings of this study validated the three constructs in value beliefs measured by an OER user survey: engaging students, customizing classroom materials and supporting personal professional development. The results showed that a considerable number of college instructors maintained a low level of value beliefs towards using OER. We further provided individualized classification for each college instructor in terms of the three types of value beliefs. In addition, this study investigated how pre-determined latent classes of value beliefs influenced college instructors' practice and perception of using OER. Particularly, college instructors who value OER to address their profession needs are more likely to adapt OER in their teaching rather than merely reusing existing copies. Practical implications of supporting higher education faculty's use of OER are discussed in the end.

Effects of puerarin on the intervertebral disc degeneration and biological characteristics of nucleus pulposus cells.

CONTEXT: Intervertebral disc degeneration (IDD) is the pathological basis of spinal degenerative diseases. Puerarin (PU) is an isoflavonoid with functions and medicinal properties. OBJECTIVE: To explore the effect of PU on IDD and its potential mechanism of action. MATERIALS AND METHODS: Sprague-Dawley (SD) rats were divided into sham, IDD, low PU, and high PU groups. Rat nucleus pulposus cells (NPCs) were isolated and divided into control, IL-1ß, 100 and 200 µmol/mL PU, TAK-242 (TLR4 inhibitor), or 200 µmol/mL PU + LPS (TLR4 activator) groups. The water content, inflammatory factors, proliferation activity, TLR4/NF-κB pathway activity, apoptosis rate, protein expression of apoptosis, and histology of the extracellular matrix (ECM) were analysed. RESULTS: In vivo: Compared with the IDD group, disorganization of intervertebral disc tissue was significantly improved, water content (2.80 ± 0.24 mg, 3.91 ± 0.31 mg vs. 2.02 ± 0.21 mg) and expression levels of collagen II and aggrecan were significantly increased, and the levels of inflammatory factors and the expression levels of TLR4, MyD88, and p-p65 were significantly decreased in IDD rats treated with PU. In vitro: Compared with the IL-1ß group, the proliferation activity of IL-1ß-treated NPCs and the expression of collagen II and aggrecan were significantly increased, while the apoptosis rate, levels of inflammatory factors, and the expression levels of TLR4, MyD88, and p-p65 were significantly decreased in IL-1ß-treated NPCs treated with PU. LPS reversed the biological function changes of IL-1ß-treated NPCs induced by PU. CONCLUSIONS: PU can delay the progression of IDD by inhibiting activation of the TLR4/NF-κB pathway.

Teachers' beliefs and practices of technology integration at a school for students with dyslexia: A mixed methods study.

The amount of technology available in schools has increased steadily over the past two decades, but higher-level uses have not followed, and many teachers continue to struggle integrating technology in their classrooms. The purpose of this study was to describe teachers' beliefs about technology in the classroom and identify whether their beliefs are reflected in practices of integrating technology at a small, private school for students with dyslexia. A convergent mixed methods action research study was conducted to understand how teachers' beliefs may be affecting technology integration at the school. Quantitative data was collected through a survey administered to all 55 teachers at the school to describe how technology was being used throughout the school. From this sample, six participants were selected for three rounds of follow-up interviews and observations. Quantitative data revealed more teacher-centered beliefs and practices of teachers at the school. Qualitative findings showed teachers with more student-centered beliefs integrated technology more in their classrooms. Findings also revealed the school culture influenced teachers' beliefs about the role of technology. Implications are provided on offering professional development adapted to teachers' levels of technology integration.

A multimodal analysis of college students' collaborative problem solving in virtual experimentation activities: a perspective of cognitive load.

Distance education programs have become the preferred option for most higher education institutions to continue teaching during the COVID-19 pandemic, but the effectiveness of some online courses, especially those engineering courses with experimentation activities, remains disputed. The main challenge is fostering collaborative problem solving skills for novice students as online collaboration increases their cognitive load. This research thus tapped into novice engineering students' cognitive load to develop a more granular, multimodal view of how cognitive load influences student performance in collaborative problem solving during virtual experimentation activities. The findings of this research provided significant implications for the future design and implementation of virtual laboratories in computer science engineering education.

Improving K-12 Teachers' Acceptance of Open Educational Resources by Open Educational Practices: A Mixed Methods Inquiry.

Teachers in K-12 settings increasingly demand instructional materials beyond textbooks to follow the upward momentum of personalized instruction. Especially during the outbreak of COVID-19, K-12 teachers are forced to quickly adapt to online teaching and thus have more difficulties of delivering personalized instruction in a relatively resource-restraint situation. Open educational resources (OER), allowing teachers to retain, reuse, revise, remix, and redistribute high-quality educational resources at no costs, can be a viable option for teachers. However, the acceptance of OER in K-12 education still remains low. Effective strategies are needed to reinforce teacher intention to adopt OER. This research showcased a two-phase sequential explanatory mixed method inquiry to investigate whether engaging K-12 teachers in open educational practices (OEP)-such as renewable assignments-increased their acceptance of OER. The quantitative phase, referring to the technology acceptance model (TAM), examined the change in factors influencing teachers' acceptance of OER. The qualitative phase was followed up to provide supplementary perspectives of the quantitative findings. By integrating complementary findings, this research found that OEP increased teachers' perceived ease of and self-efficacy towards using OER. Although teachers' intention of implementing OER is not significantly improved, qualitative findings offered additional insights into the benefits of OEP in promoting OER usage and the recommended directions for future effort. Practical implications on improving teachers' acceptance of OER in K-12 curriculum are discussed at the end.

Enhanced isomerization of rare sugars by ribose-5-phosphate isomerase A from Ochrobactrum sp. CSL1.

Ribose-5-phosphate isomerase A (RpiA) is of great importance in biochemistry research, however its application in biotechnology has not been fully explored. In this study the activity of RpiA from Ochrobactrum sp. CSL1 (OsRpiA) towards D-allose was engineered based on sequential and structural analyses. Strategies of alanine scanning, rational design and saturated mutagenesis were employed to create three mutant libraries. A single mutant of K124A showed a 45 % activity improvement towards D-allose. The reaction properties of the mutant were analyzed, and a shift of optimal pH and higher thermal stability at low reaction temperatures were identified. The conversion of D-allose was also improved by 40 % using K124A, and higher activities on major substrates were found in the mutant's substrate scope, implying its application potential in rare sugar preparation. Kinetics analysis revealed that Km of K124A mutant decreased by 12 % and the catalytic efficiency increased by 65 % towards D-allose. Moreover, molecular dynamics simulation illustrated the binding of substrate and K124A was more stable than that of the wild-type. The shorter distance and more relax bond angle between the catalytic residue of K124A and D-allose explained the activity improvement in detail. This study highlights the potential of OsRpiA as a biocatalyst for rare sugar preparation, and provides distinct evidences for its catalytic mechanism.

Engineering ribose-5-phosphate isomerase B from a central carbon metabolic enzyme to a promising sugar biocatalyst.

Ribose-5-phosphate isomerase B (RpiB) was first identified in the pentose phosphate pathway responsible for the inter-conversion of ribose-5-phosphate and ribulose-5-phosphate. Though there are seldom key enzymes in central carbon metabolic system developed as useful biocatalysts, RpiB with the advantages of wide substrate scope and high stereoselectivity has become a potential biotechnological tool to fulfill the demand of rare sugars currently. In this review, the pivotal roles of RpiB in carbon metabolism are summarized, and their sequence identity and structural similarity are discussed. Substrate binding and catalytic mechanisms are illustrated to provide solid foundations for enzyme engineering. Interesting differences in origin, physiological function, structure, and catalytic mechanism between RpiB and ribose-5-phosphate isomerase A are introduced. Moreover, enzyme engineering efforts for rare sugar production are stressed, and prospects of future development are concluded briefly in the viewpoint of biocatalysis. Aided by the progresses of structural and computational biology, the application of RpiB will be promoted greatly in the preparation of valuable molecules. KEY POINTS: • Detailed illustration of RpiB's vital function in central carbon metabolism. • Potential of RpiB in sequence, substrate scope, and mechanism for application. • Enzyme engineering efforts to promote RpiB in the preparation of rare sugars.

Implementing open educational resources in digital education.

The outbreak of COVID-19 leads to an increasing demand for online educational resources to continue teaching and learning. Open educational resources (OER), with the benefits of cost-saving and open licenses, have great potential in facilitating the rapid transition to digital education, but concerns about whether OER decrease the effectiveness of student learning remains unsolved. Hilton's review article (2016) provides synthesized evidence stating that OER can help decrease college students' textbook spending without undermining student learning effectiveness. It is also noteworthy that implementing OER in digital education needs additional considerations beyond the efficacy of OER. Therefore, this special issue article extends Hilton's (2016) synthesized findings by presenting four additional perspectives in research, design, culture, practice about implementing OER in digital education.

Ubiquitin-specific protease 49 attenuates IL-1ß-induced rat primary chondrocyte apoptosis by facilitating Axin deubiquitination and subsequent Wnt/ß-catenin signaling cascade inhibition.

Osteoarthritis (OA) is an age-related chronic joint degenerative disease. Interleukin 1 beta (IL-1ß) is considered a marker for the progression of OA. In this study, we found that Ubiquitin-Specific Peptidase 49 (USP49) was significantly less expressed in OA patients compared with healthy individuals. Treating primary rat chondrocytes with different concentrations of IL-1ß resulted in decreased Usp49 expression, while Usp49 overexpression could attenuate IL-1ß-induced chondrocyte apoptosis by promoting Axin deubiquitination. The deubiquitination of Axin led to the accumulation of the protein, which in turn resulted in ß-catenin degradation and Wnt/ß-catenin signaling cascade inhibition. Interestingly, we also found that [6]-gingerol, an anti-OA drug, could upregulate the protein level of Usp49 and suppress the Wnt/ß-catenin signaling cascade in primary rat chondrocytes. Taken together, our study not only demonstrates that Usp49 can negatively regulate the progression of OA by inhibiting the Wnt/ß-catenin signaling cascade, but also elucidates the underlying molecular mechanisms.

Exploring Multifunctional Residues of Ribose-5-phosphate Isomerase B from Ochrobactrum sp. CSL1 Enhancing Isomerization of d-Allose.

Ribose-5-phosphate isomerase B is of great importance for biocatalysis and biosynthesis, but the multifunctional residues in active sites hinder the research efforts. This study employed rational design strategies to locate the key residues of RpiB from Ochrobactrum sp. CSL1 (OsRpiB). A single-mutant S9T of a noncontact residue showed 80% activity improvement toward d-allose. A double-mutant S98H/S134H further increased the activity to 3.6-fold. The mutations were analyzed by kinetics and molecular dynamics analyses, indicating that S9T might enhance the substrate binding and catalysis by inducing a steric effect, and S98H/S134H could strengthen both ring opening and binding of d-allose. Though S98H/S134H showed low temperature stability, its potential was explored by isomerizing d-allose to d-psicose with higher conversion and in less reaction time. The findings of this study were beneficial for illustrating the complex functions of key residues in RpiBs and applying OsRpiB in preparing rare sugars.

DRP5 is involved in cancer cell growth and predicts poor prognosis in human osteosarcoma.

Osteosarcoma is an extremely aggressive primary malignant bone tumor of childhood. Collapsin response mediator proteins (CRMPs), which are highly expressed in the developing nervous system, were recently shown to be associated with cancer development. However, the relationship between DRP5 (CRMP5) and osteosarcoma has not been evaluated. In this study, we investigated the role of DRP5 in the regulation of osteosarcoma growth. DRP5 mRNA and protein levels were significantly upregulated in human osteosarcoma cell lines and associated with increased migration and invasion. Genetic knockdown of DRP5 markedly suppressed the expression of matrix metalloproteinase (MMP)-2 and MMP-9. DRP5 silencing significantly inhibited osteosarcoma cell growth in vitro and in a xenograft mouse model in vivo. Microarray immunohistochemical analysis of osteosarcoma specimens and Kaplan-Meier analysis showed that patients with high DRP5 protein expression had shorter overall survival than those with low DRP5 levels. Taken together, these results suggest that DRP5 plays a critical role in the regulation of osteosarcoma and could be a potential therapeutic target and prognostic factor in osteosarcoma.

[Mid-term effectiveness of Oxford Unicompartmental Knee System Phase III for medial unicompartmental knee osteoarthritis].

OBJECTIVE: To evaluate the mid-term effectiveness of Oxford Unicompartmental Knee system Phase III for medial unicompartmental knee osteoarthritis (OA). METHODS: Between December 2008 and August 2010, 26 patients (32 knees) with medial unicompartmental knee OA were treated. Of 26 patients, 11 were followed up more than 2 years, including 7 males and 4 females (14 knees, 6 left and 8 right knees) with an average age of 62.4 years (range, 50-74 years). All patients had load suffering and tenderness of medial unicompartmental knee, and complicated by varus deformity without limitation of flexion and extension; the disease duration ranged 5-23 years (mean, 11.6 years). According to Ahlback staging, 4 knees were at stage II and 10 knees at stage III. Cemented unicompartmental knee arthroplasty (Oxford Unicompartmental Knee system Phase III) was performed by minimally invasive technique. RESULTS: All the incisions were primary healing after operation. Five cases suffered from local ache in the pes anserinus during the first 3 months after operation, which was cured after conservative therapy. Of them, 11 patients were followed up 27.5 months on average (range, 24-30 months). During follow-up, no complication of prosthesis loosening, displacement, arthropathy in the opposite department, or the patellofemoral joint occurred. The range of motion was significantly improved from (109.2 +/- 8.7) degrees preoperatively to (123.5 +/- 6.7) degrees at last followup (P < 0.05); knee society score (KSS) and Western Ontario and McMaster University Osteoarthritis Index (WOMAC) scores were all significantly improved (P < 0.05). At last follow-up, the femoro-tibial angle was significantly improved (P < 0.05); tibial plateau and the tibial anatomical axis increased, showing no significant difference (P > 0.05); and posterior tibial slope was significantly decreased (P < 0.05). CONCLUSION: Oxford Unicompartmental Knee system Phase III has satisfactory mid-term effectiveness in treating medial unicompartmental knee OA with the advantages of little trauma and rapid recovery, but long-term effectiveness is expected for further follow-up.

[Arthroscopically assisted treatment for acute patellar dislocation].

OBJECTIVE: To evaluate an improving operative procedure and the clinical results of arthroscopically assisted treatment for acute patellar dislocation. METHODS: Between April 2006 and March 2009, 22 patients (25 knees) with primary acute complete dislocation of the patella underwent an improving arthroscopic operation, release of lateral retinaculum and suture of medial capsule and retinaculum structure. There were 5 males and 17 females with an average age of 23.6 years (range, 14-34 years). Three patients had bilateral procedure. Eleven left knees and 14 right knees were involved. The disease duration was 1-10 days with an average of 5.9 days. All patients had lateral dislocation; of them, 14 patients showed reduction without treatment, and 8 patients showed dislocation at admission and were given close manipulative reduction. The results were positive for apprehension test in all patients with the limitation of passive motion and for Ballottable Patella Sign in 15 cases. Lysholm score, visual analogue scale (VAS) score, and Insall scale were adopted to evaluate the effect. RESULTS: All incisions healed by first intention. All the patients were followed up 12-36 months (17 months on average). During the first 3 months after operation, sunken skin in the puncture point medial to the patella was observed in 12 knees; 10 knees suffered pain of the soft tissue lateral to the patella; 15 knees felt tense in the soft tissue medial to the patella, however, all these problems disappeared or recovered gradually after rehabilitation and conservative treatment. No recurrence of dislocation was observed during the follow-up. Lysholm score was significantly improved from preoperative 67.3 +/- 5.7 to postoperative 96.6 +/- 4.5 (t = 3.241, P = 0.003) and VAS score from 6.5 +/- 0.5 to 1.8 +/- 0.4 (t = 2.154, P = 0.040). According to Insall scale, the results were excellent in 18 knees, good in 5 knees, and fair in 2 knees at 1 year after operation with an excellent and good rate of 92%. CONCLUSION: The improving procedure of arthroscopically assisted treatment for acute patellar dislocation is a minimally invasive operation and has a number of benefits. Its short-term clinical outcome was satisfactory.