Full-length radiograph based automatic musculoskeletal modeling using convolutional neural network.

Full-length radiographs contain information from which many anatomical parameters of the pelvis, femur, and tibia may be derived, but only a few anatomical parameters are used for musculoskeletal modeling. This study aimed to develop a fully automatic algorithm to extract anatomical parameters from full-length radiograph to generate a musculoskeletal model that is more accurate than linear scaled one. A U-Net convolutional neural network was trained to segment the pelvis, femur, and tibia from the full-length radiograph. Eight anatomic parameters (six for length and width, two for angles) were automatically extracted from the bone segmentation masks and used to generate the musculoskeletal model. Sørensen-Dice coefficient was used to quantify the consistency of automatic bone segmentation masks with manually segmented labels. Maximum distance error, root mean square (RMS) distance error and Jaccard index (JI) were used to evaluate the geometric accuracy of the automatically generated pelvis, femur and tibia models versus CT bone models. Mean Sørensen-Dice coefficients for the pelvis, femur and tibia 2D segmentation masks were 0.9898, 0.9822 and 0.9786, respectively. The algorithm-driven bone models were closer to the 3D CT bone models than the scaled generic models in geometry, with significantly lower maximum distance error (28.3 % average decrease from 24.35 mm) and RMS distance error (28.9 % average decrease from 9.55 mm) and higher JI (17.2 % average increase from 0.46) (P < 0.001). The algorithm-driven musculoskeletal modeling (107.15 ± 10.24 s) was faster than the manual process (870.07 ± 44.79 s) for the same full-length radiograph. This algorithm provides a fully automatic way to generate a musculoskeletal model from full-length radiograph that achieves an approximately 30 % reduction in distance errors, which could enable personalized musculoskeletal simulation based on full-length radiograph for large scale OA populations.

Molecular Dynamics and In Vitro Studies Elucidating the Tunable Features of Reconfigurable Nanodiscs for Guiding the Optimal Design of Curcumin Formulation.

In this study, we advance our exploration of Apolipoprotein A-I (apoA-I) peptide analogs (APAs) for their application in nanodisc (ND) assembly, focusing on the dynamic conformational characteristics and the potential for drug delivery. We explore APA-ND interactions with an emphasis on curcumin encapsulation, utilizing molecular dynamic simulations and in vitro assessments to evaluate the efficacy of various APA-ND formulations as drug carriers. The methodological approach involved the generation of three unique apoA-I α-11/3 helical mimics, resulting in fifteen distinct APAs. Their structural integrity was rigorously assessed using ColabFold-AF2, with particular attention to pLDDT and pTM scores. Extensive molecular dynamics simulations, covering 1.7 µs across 17 ND systems, were conducted to investigate the influence of APA sequence variations on ND stability and interactions. This study reveals that the composition of APAs, notably the presence of Proline, Serine, and Tryptophan, significantly impacts ND stability and morphology. Oligomeric APAs, in particular, demonstrated superior stability and distinct interaction patterns compared to their monomeric counterparts. Additionally, hydrodynamic diameter measurements over eight weeks indicated sequence-dependent stability, highlighting the potential of specific APA configurations for sustained colloidal stability. In vitro study successfully encapsulated curcumin in [AA]3/DMPC ND formulations, revealing concentration-dependent stability and interaction dynamics. The findings underscore the remarkable capability of APA-NDs to maintain structural integrity and efficient drug encapsulation, positioning them as a promising platform for drug delivery. The study concludes by emphasizing the tunability and versatility of APA-NDs in drug formulation, potentially revolutionizing nanomedicine by enabling customized APA sequences and ND properties for targeted drug delivery.

Incidence and predictors of restenosis following successful recanalization of non-acute internal carotid artery occlusion in 252 cases.

BACKGROUND: Data concerning restenosis following successful recanalization of non-acute internal carotid artery occlusion (ICAO) are scarce. This study was conducted to identify the incidence and predictors of restenosis following successful recanalization of non-acute ICAO. METHODS: We reviewed the incidence of restenosis (defined as >70% restenosis or reocclusion) among 252 consecutive patients with successful recanalization of non-acute ICAO. Baseline, imaging, and surgery-related characteristics were analyzed to assess their association with restenosis. A scoring system was developed to identify high-risk patients for restenosis. RESULTS: During a median follow-up of 12.6 months, restenosis occurred in 56 patients (22.2%), including 39 with reocclusion and 17 with >70% restenosis. The cumulative restenosis rate was 18.0% at 12 months and 24.1% at 24 months. The incidence of stroke was higher in patients with restenosis (25.0% vs 1.5%, P<0.01). Multivariate analysis showed occlusion length (5-10 cm vs <5 cm (hazard ratio (HR) 3.15, 95% confidence interval (95% CI) 1.07 to 9.29); ≥ 10 cm vs <5 cm (HR 5.01, 95% CI 1.73 to 14.49)), residual stenosis ≥30% (HR 3.08, 95% CI 1.79 to 5.30), and internal carotid artery (ICA) wall collapse (HR 1.96, 95% CI 1.12 to 3.44) as independent predictors of restenosis. Point scores proportional to model coefficients were assigned, with scores ranging from 0 to 6. Patients scoring 3-6 had a 4.00 times higher chance of developing restenosis (95% CI 2.35 to 6.79) compared with those scoring 0-2. CONCLUSIONS: Nearly one in five patients experienced restenosis following successful recanalization of non-acute ICAO. Occlusion length, residual stenosis ≥30%, and ICA wall collapse were independently associated with restenosis.

Assessment of intestinal luminal stenosis and prediction of endoscopy passage in Crohn's disease patients using MRI.

BACKGROUND: Crohn's disease (CD) is an inflammatory disease of the gastrointestinal tract. The disease behavior changes over time, and endoscopy is crucial in evaluating and monitoring the course of CD. To reduce the economic burden of patients and alleviate the discomfort associated with ineffective examination, it is necessary to fully understand the location, extent, and severity of intestinal stenosis in patients with CD before endoscopy. This study aimed to utilize imaging features of magnetic resonance enterography (MRE) to evaluate intestinal stenosis in patients with CD and to predict whether endoscopy could be passed. METHODS: MRE data of patients with CD were collected, while age, gender, disease duration, and laboratory test parameters were also gathered. Two radiologists analyzed the images and assessed whether endoscopy could be passed based on the imaging performance. Imaging features of MRE were analyzed in groups based on endoscopy results. RESULTS: The readers evaluated the imaging performance for 86 patients to determine if endoscopy could be passed and performed a consistency test (compared between two readers k = 0.812, p = 0.000). In the univariate analysis, statistical differences were observed in the degree of T1WI enhancement, thickness of the intestine wall at the stenosis, and diameter of the upstream intestine between the two groups of whether endoscopy was passed. In multivariate logistic regression, the diameter of the upstream intestine was identified to be an independent factor in predicting whether endoscopy was passed or not (OR = 3.260, p = 0.046). CONCLUSIONS: The utilization of MRE signs for assessing the passage of an endoscope through the narrow segment revealed that the diameter of the upstream intestine emerged as an independent predictor of endoscopic passage. Before performing an endoscopy, MRE can aid in evaluating the passage of the endoscope. CRITICAL RELEVANCE STATEMENT: This retrospective study explored the imaging features of MRE to evaluate intestinal stenosis in patients with Crohn's disease and determined that the diameter of the upstream intestine of the stenotic segment was an independent predictor in assessing endoscopic passage. KEY POINTS: • Endoscopy is crucial in evaluating and monitoring the course of Crohn's disease. • The diameter of the upstream intestine of the stenotic segment was an independent predictor in assessing endoscopic passage. • MRE can aid in evaluating the passage of the endoscope in stenotic segments of Crohn's disease.

Alternative splicing-related long noncoding RNA ANRIL facilitates hepatocellular carcinoma by targeting the miR-199a-5p/SRSF1 axis and impacting Anillin.

Hepatocellular carcinoma (HCC) is characterized by aberrant alternative splicing (AS), which plays an important part in the pathological process of this disease. However, available reports about genes and mechanisms involved in AS process are limited. Our previous research has identified ANRIL as a long noncoding RNA related to the AS process of HCC. Here, we investigated the exact effect and the mechanism of ANRIL on HCC progress. The ANRIL expression profile was validated using the real-time quantitative polymerase chain reaction assay. The western blot analysis and IHC assay were conducted on candidate targets, including SRSF1 and Anillin. The clinicopathological features of 97 patients were collected and analyzed. Loss-of and gain-of-function experiments were conducted. The dual-luciferase reporter assay was applied to verify the interaction between ANRIL, miR-199a-5p, and SRSF1. Anomalous upregulation of ANRIL in HCC was observed, correlating with worse clinicopathological features of HCC. HCC cell proliferation, mobility, tumorigenesis, and metastasis were impaired by depleting ANRIL. We found that ANRIL acts as a sponger of miRNA-199a-5p, resulting in an elevated level of its target protein SRSF1. The phenotypes induced by ANRIL/miR-199a-5p/SRSF1 alteration are associated with Anillin, a validated HCC promoter. ANRIL is an AS-related lncRNA promoting HCC progress by modulating the miR-199a-5p/SRSF1 axis. The downstream effector of this axis in the development of HCC is Anillin.

BRCA2, PALB2, RECQL4 Germline Pathogenic Variants, and Somatic TP53 Mutation in Triple Metachronous Malignancies: A Case Report and Literature Review.

Background: Multiple primary cancer (MPC) refers to the presence of more than one cancer in an individual. Triple primary malignancies are uncommon. Case: We report the case of a 50-year-old postmenopausal woman in our gynecology department, diagnosed with endometrial cancer, ovarian cancer, and unilateral breast cancer. She carried germline mutations in BRCA2, PALB2, and RECQL4, along with a somatic pathogenic variant in TP53. Endometrial cancer patients harboring germline pathogenic variants in BRCA2 exhibit a heightened risk of ovarian and breast cancer. BRCA2 is known to play a role in the development of ovarian and breast cancer, while PALB2 is identified as a gene associated with breast cancer susceptibility. RECQL4 has been linked to breast cancer, cervical cancer, and other tumors. Conclusion: Genetic testing may be imperative for identifying MPC in endometrial cancer patients. For individuals with BRCA2 and other gene pathogenic variants, routine examination and monitoring of the endometrium, ovaries, breasts, and other sites prone to polygenic cancer are recommended.

The Effects of Long-Term Walking Exercise on Structural Progression, Symptoms, and Extensor Muscle Strength in Patients with Mild or at High Risk of Knee Osteoarthritis: Data from the Osteoarthritis Initiative.

OBJECTIVE: To assess the relationship between walking exercise and medial joint space narrowing (JSN) progression, symptoms, and knee extensor muscle strength (EMS) in early knee osteoarthritis (OA) patients. METHODS: This nested cohort study within the Osteoarthritis Initiative included participants aged 50 and above with knee OA (Kellgren-Lawrence grades 0-2). Walking exercisers were identified using a modified Historical Physical Activity Survey Instrument. Differences in medial JSN, Knee Injury and Osteoarthritis Outcome Score (KOOS), and knee EMS were evaluated through the three-way ANOVA. RESULTS: Among 896 participants, 83.4% reported walking exercise. Female walkers showed significant improvements in symptoms (KOOS-Pain: P < 0.001; KOOS-Symptom: P < 0.001; KOOS-Quality of Life (QOL): P < 0.001; KOOS-Function, Sports, and Recreational Activities (FSR): P = 0.007). Similar results were observed in male walkers (KOOS-Pain: P < 0.001; KOOS-Symptom: P < 0.001; KOOS- QOL: P = 0.001; KOOS- FSR: P = 0.009). Walkers showed significantly increased knee EMS at 24 months (Female: P < 0.001; Male: P = 0.003). Female non-walkers had significantly decreased knee EMS at 24 months (P < 0.001). Walkers showed significant improvement in medial JSN (OR = 1.1, 95% CI: 1.0 to 1.2) and KL grade (OR = 1.0, 95% CI: 1.0 to 1.1) compared to non-walkers. CONCLUSION: Walking exercise prevents structural progression and improves symptoms. Meanwhile, the increased knee EMS in all walkers further supports the validity of recommending walking exercises for early-stage knee OA patients.

Biosynthesis of 10-Hydroxy-2-decenoic Acid through a One-Step Whole-Cell Catalysis.

10-Hydroxy-2-decenoic acid (10-HDA) is an important component of royal jelly, known for its antimicrobial, anti-inflammatory, blood pressure-lowering, and antiradiation effects. Currently, 10-HDA biosynthesis is limited by the substrate selectivity of acyl-coenzyme A dehydrogenase, which restricts the technique to a two-step process. This study aimed to develop an efficient and simplified method for synthesizing 10-HDA. In this study, ACOX from Candida tropicalis 1798, which catalyzes 10-hydroxydecanoyl coenzyme A desaturation for 10-HDA synthesis, was isolated and heterologously coexpressed with FadE, Macs, YdiI, and CYP in Escherichia coli/SK after knocking out FadB, FadJ, and FadR genes. The engineered E. coli/AKS strain achieved a 49.8% conversion of decanoic acid to 10-HDA. CYP expression was improved through ultraviolet mutagenesis and high-throughput screening, increased substrate conversion to 75.6%, and the synthesis of 10-HDA was increased to 0.628 g/L in 10 h. This is the highest conversion rate and product concentration achieved in the shortest time to date. This study provides a simple and efficient method for 10-HDA biosynthesis and offers an effective method for developing strains with high product yields.

Home-based tele-rehabilitation versus hospital-based outpatient rehabilitation for pain and function after initial total knee arthroplasty: A systematic review and meta-analysis.

BACKGROUND: This systematic review and meta-analysis aims to compare the effectiveness of home-based tele-rehabilitation programs with hospital-based rehabilitation programs in improving pain and function at various time points (≤6 weeks, ≤14 weeks, and ≤ 52 weeks) following the initial total knee arthroplasty. METHODS: This study used PRISMA and AMSTAR reporting guidelines. We systematically searched 5 databases (PubMed, Embase, Web of Science, Cochrane Library, and Medline) to identify randomized controlled trials published from January 1, 2019, to January 1, 2023. The primary outcomes were pain, knee injury and osteoarthritis outcome score, and mobility (knee range of motion). RESULTS: We included 9 studies involving 1944 patients. Low-quality evidence showed hospital-based rehabilitation was better than home-based tele-rehabilitation in knee injury and osteoarthritis outcome score (mean difference [MD], -2.62; 95% confidence interval [CI], -4.65 to -0.58; P = .01) at ≤ 14 weeks after total knee arthroplasty. Based on low-quality evidence, home-based tele-rehabilitation was better than hospital-based rehabilitation in knee range of motion (MD, 2.00; 95% CI, 0.60 to 3.40; P = .005). There was no significant difference between hospital-based rehabilitation and home-based tele-rehabilitation in knee pain at ≤ 6 weeks (MD, 0.18; 95% CI, -0.07 to 0.42; P = .16), 14 weeks (MD, 0.12; 95% CI, -0.26 to 0.49; P = .54), and ≤ 52 weeks (MD, 0.16; 95% CI, -0.11 to 0.43; P = .24). CONCLUSION: Home-based tele-rehabilitation and hospital-based rehabilitation programs showed comparable long-term outcomes in pain, mobility, physical function, and patient-reported health status after primary total knee arthroplasty. Considering the economic costs, home-based tele-rehabilitation programs are recommended as a viable alternative to hospital-based rehabilitation programs.

Translational Challenges and Prospective Solutions in the Implementation of Biomimetic Delivery Systems.

Biomimetic delivery systems (BDSs), inspired by the intricate designs of biological systems, have emerged as a groundbreaking paradigm in nanomedicine, offering unparalleled advantages in therapeutic delivery. These systems, encompassing platforms such as liposomes, protein-based nanoparticles, extracellular vesicles, and polysaccharides, are lauded for their targeted delivery, minimized side effects, and enhanced therapeutic outcomes. However, the translation of BDSs from research settings to clinical applications is fraught with challenges, including reproducibility concerns, physiological stability, and rigorous efficacy and safety evaluations. Furthermore, the innovative nature of BDSs demands the reevaluation and evolution of existing regulatory and ethical frameworks. This review provides an overview of BDSs and delves into the multifaceted translational challenges and present emerging solutions, underscored by real-world case studies. Emphasizing the potential of BDSs to redefine healthcare, we advocate for sustained interdisciplinary collaboration and research. As our understanding of biological systems deepens, the future of BDSs in clinical translation appears promising, with a focus on personalized medicine and refined patient-specific delivery systems.

Autologous CIK cells combined with chemotherapy as the first-line treatment for locally advanced or metastatic gastric cancer is safe and feasible.

Aim: To evaluate the safety and initial efficacy of autologous cytokine-induced killer (CIK) cells combined with S-1+oxaliplatin (SOX) as the first-line treatment for locally advanced or metastatic gastric cancer (GC). Materials and methods: In this two-arm, single-center exploratory trial, patients with locally advanced or metastatic GC were randomly assigned (1:1) to receive autologous CIK cells in combination with SOX (CIK-SOX) or SOX alone. The primary endpoint was the incidence of adverse events (AEs). Progression-free survival (PFS), overall survival (OS), objective response rate (ORR), and disease control rate (DCR) served as the secondary endpoints. Results: Fifty-nine patients were enrolled in the study between November 20, 2014 and September 6, 2017. A total of 31 patients received CIK-SOX and 28 patients received SOX. The most common AEs in both groups were gastrointestinal reaction, leucopenia, neutropenia, anemia, thrombocytopenia, hyperbilirubinemia, and elevated aspartate transaminase concentration, with a higher incidence of these conditions in the SOX group. The median PFS for the CIK-SOX and SOX groups was 6.9 and 4.9 months, respectively (hazard ratio (HR) 0.80, p=0.45). The respective median OS values were 17.8 and 9.75 months (HR 0.76, p=0.34). Patients who received more than three injections of specific lymphocyte subsets benefited the most from this combination therapy. Cox univariate and multivariate analyses showed that tumor metastasis to more than two organs was the main risk factor for PFS and OS. A total of 29 patients in the CIK-SOX group and 25 in the SOX group had measurable lesions. The ORR for the CIK-SOX and SOX groups was 55.2% and 32.0%, while the DCR was 93.1% and 88.0%, respectively. Conclusion: The safety of CIK-SOX as the first-line treatment for patients with locally advanced or metastatic GC was good. Although the PFS and OS in the CIK-SOX group were not statistically significantly different compared to the values in the SOX alone group, this treatment increased the PFS and OS duration, with the absolute improvement in OS of about 8.05 months. Continuous benefit from the CIK-SOX treatment was observed during long-term follow-up. Clinical trial registration: https://clinicaltrials.gov/study/NCT02504229?term=NCT02504229&rank=1, identifier ChiCTR-IPR-15005923; NCT02504229.

Attenuation of binuclear hepatocytes in the paracancerous liver tissue is associated with short-term recurrence of hepatocellular carcinoma post-radical surgery.

Short-term recurrence of hepatocellular carcinoma (HCC) after radical resection leads to dismal outcomes. To screen high-recurrence risk patients to provide adjuvant treatment is necessary. Herein, based on our previous research, we further focused on the changes in the abundance of binuclear hepatocytes (ABH) in the paracancerous liver tissue to discuss the relationship between the attenuation of binuclear hepatocytes and postoperative short-term recurrence, by combining with the assessment of the value of a reported independent early recurrence risk factor in HCC, protein induced by vitamin K absence or antagonist-II (PIVKA-II). A cohort of 142 paracancerous liver tissues from HCC patients who received radical resection was collected. Binuclear hepatocytes were reduced in the paracancerous liver tissues, compared with the liver tissues from normal donors. ABH was negatively correlated with clinical features such as tumor size, TNM stages, tumor microsatellite formation, venous invasion, and Alpha-fetoprotein (AFP) level, as well as the expression of E2F7 and Anillin, which are two critical regulators concerning the hepatocyte polyploidization. According to the short-term recurrence information, ABH value was laminated, and univariate and multivariate logistic regression was performed to analyze the relationship between paracancerous ABH and short-term tumor relapse. Simultaneously, the predictive effectiveness of the ABH value was compared with the preoperative PIVKA-II value. As observed, the paracancerous ABH value below 1.5% was found to be an independent risk factor for recurrence. In conclusion, the paracancerous ABH is a credible indicator of short-term recurrence of HCC patients after radical resection, and regular assessment of ABH might help to prevent short-term HCC recurrence.

Neratinib for HER2-positive breast cancer with an overlooked option.

Positive human epidermal growth factor receptor 2 (HER2) expression is associated with an increased risk of metastases especially those to the brain in patients with advanced breast cancer (BC). Neratinib as a tyrosine kinase inhibitor can prevent the transduction of HER1, HER2 and HER4 signaling pathways thus playing an anticancer effect. Moreover, neratinib has a certain efficacy to reverse drug resistance in patients with BC with previous HER2 monoclonal antibody or targeted drug resistance. Neratinib, as monotherapy and in combination with other therapies, has been tested in the neoadjuvant, adjuvant, and metastatic settings. Neratinib with high anticancer activity is indicated for the prolonged adjuvant treatment of HER2-positive early BC, or in combination with other drugs including trastuzumab, capecitabine, and paclitaxel for the treatment of advanced HER2-positive BC especially cancers with central nervous system (CNS) metastasis to reduce the risk of BC recurrence. This article reviewed the pharmacological profiles, efficacy, safety, tolerability, and current clinical trials pertaining to neratinib, with a particular focus on the use of neratinib in patients with metastatic breast cancer (MBC) involving the CNS. We further discussed the use of neratinib for HER2-negative and HER2-mutant breast cancers, and mechanisms of resistance to neratinib. The current evidence suggests that neratinib has promising efficacy in patients with BC which is at least non-inferior compared to previous therapeutic regimens. The most common AE was diarrhea, and the incidence, severity and duration of neratinib-related grade 3 diarrhea can be reduced with loperamide. Of note, neratinib has the potential to effectively control and prevent brain metastasis in patients with advanced BC, providing a therapeutic strategy for HER2-positive BC.

A specific and rapid method for detecting Bacillus and Acinetobacter species in Daqu.

Daqu is a spontaneous, solid-state cereal fermentation product used for saccharification and as a starter culture for Chinese Baijiu production. Bacillus and Acinetobacter, two dominant microbial genera in Daqu, produce enzymes and organic acids that influence the Daqu quality. However, there are no rapid analytical methods for detecting Bacillus and Acinetobacter. We designed primers specific to the genera Bacillus and Acinetobacter to perform genetic comparisons using the 16 S rRNA. After amplification of polymerase chain reaction using specific primers, high-throughput sequencing was performed to detect strains of Bacillus and Acinetobacter. The results showed that the effective amplification rates for Bacillus and Acinetobacter in Daqu were 86.92% and 79.75%, respectively. Thus, we have devised and assessed a method to accurately identify the species associated with Bacillus and Acinetobacter in Daqu, which can also hold significance for bacterial typing and identification.

Flow-cytometric cell sorting coupled with UV mutagenesis for improving pectin lyase expression.

Introduction: Alkaline pectin lyase is an important enzyme with a wide range of applications in industrial production, It has been widely used in many important fields such as fruit juice processing and extraction, the dyeing and processing of cotton and linen textiles, degumming plant fibers, environmental industrial wastewater treatment, and pulp and paper production. PGLA-rep4 was previously generated as a modified alkaline pectin lyase with high specific activity at pH 11.0°C and 70°C. However, the pre-constructed high-activity pectin lyase expression strains are still difficult to apply in industrial production due to their limited enzymatic activity. We hope to solve these problems by combining modern breeding techniques with high-throughput equipment to rapidly screen alkaline pectin lyase with higher enzymatic activity and lower cost. Methods: We fused the genes encoding PGLA-rep4 and fluorescent protein egfp using a flexible linker peptide and ligated them into a temperature-sensitive plasmid, pKD46. The constructed screening plasmid pKD46-PGLA-rep4-egfp was then transformed into an expression host and screened via flow-cytometric cell sorting coupled with UV mutagenesis. Results: Following mutagenesis, primary screening, and secondary screening, the high-expression strain, named Escherichia coli BL21/1G3, was obtained. The screening plasmid pKD46-PGLA-rep4-egfp was eliminated, and the original expression plasmid pET28a-PGLA-rep4 was then retransformed into the mutant strains. After induction and fermentation, pectin lyase activity in E. coli BL21/1G3 was significantly increased (1.37-fold relative to that in the parental E. coli BL21/PGLA-rep4 strain, p < 0.001), and the highest activity was 230, 240 U/mL at 144 h. Genome sequencing revealed that genes encoding ribonuclease E (RNase E) and diadenosine tetraphosphatase (ApaH) of E. coli BL21/1G3 were mutated compared to the sequence in the original E. coli BL21 (DE3) strain, which could be associated with increased enzyme expression. Discussion: Our work provides an effective method for the construction of strains expressing pectin lyase at high levels.

Improvement of optimum pH and specific activity of pectate lyase from Bacillus RN.1 using loop replacement.

Background: Alkaline pectate lyase plays an important role in papermaking, biological refining and wastewater treatment, but its industrial applications are largely limited owing to its low activity and poor alkali resistance. Methods: The alkaline pectate lyase BspPel from Bacillus RN.1 was heterologously expressed in Escherichia coli BL21 (DE3) and its activity and alkali resistance were improved by loop replacement. Simultaneously, the effect of R260 on enzyme alkaline tolerance was also explored. Results: Recombinant pectate lyase (BspPel-th) showed the highest activity at 60°C and pH 11.0, and showed significant stability over a wide pH range (3.0-11.0). The specific enzyme activity after purification was 139.4 U/mg, which was 4.4 times higher than that of the wild-type enzyme. BspPel-th has good affinity for apple pectin, since the V max and K m were 29 µmol/min. mL and 0.46 mol/L, respectively. Molecular dynamics simulation results showed that the flexibility of the loop region of BspPel-th was improved. Conclusion: The modified BspPel-th has considerable potential for industrial applications with high pH processes.

Improving the regeneration rate of deep lethal mutant protoplasts by fusion to promote efficient L-lysine fermentation.

BACKGROUND: L-lysine is widely used for feed and special diet products. The transformation of fermentation strains plays a decisive role in the development of these industries. Based on the mutation breeding theory and metabolic engineering methods, this study aimed to improve the regeneration rate of high-lethality protoplasts by combining multiple mutagenesis and homologous cell fusion techniques to efficiently concentrate multiple dominant mutations and optimize the L-lysine production strain Escherichia coli QDW. RESULTS: In order to obtain the best protoplasts, the optimal enzymolysis time was selected as 4 h. The optimal lysozyme concentration was estimated at 0.8 mg/mL, because the protoplast formation rate and regeneration rate reached 90% and 30%, respectively, and their product reached the maximum. In this study, it was necessary that UV mutagenesis be excessive to obtain an expanded mutation library. For high lethality protoplasts, under the premise of minimal influence on its recovery, the optimal time for UV mutagenesis of protoplasts was 7 min, and the optimal time for thermal inactivation of protoplasts at 85 ℃ was 30 min. After homologous fusion, four fusion strains of E. coli were obtained, and their stability was analyzed by flow cytometry. The L-lysine yield of QDW-UH3 increased by 7.2% compared with that of QDW in a fermentation experiment, which promoted the expression of key enzymes in L-lysine synthesis, indicating that the combination of ultraviolet mutagenic breeding and protoplast fusion technology improved the acid-production level of the fusion strain. CONCLUSION: This method provides a novel approach for the targeted construction of microbial cell factories.

Design and application of artificial rare L-lysine codons in Corynebacterium glutamicum.

Background: L-lysine is widely used in the feed, food, and pharmaceutical industries, and screening for high L-lysine-producing strains has become a key goal for the industry. Methods: We constructed the rare L-lysine codon AAA by corresponding tRNA promoter replacement in C. glutamicum. Additionally, a screening marker related to the intracellular L-lysine content was constructed by converting all L-lysine codons of enhanced green fluorescent protein (EGFP) into the artificial rare codon AAA. The artificial EGFP was then ligated into pEC-XK99E and transformed into competent Corynebacterium glutamicum 23604 cells with the rare L-lysine codon. After atmospheric and room-temperature plasma mutation and induction culture, 55 mutants (0.01% of total cells) with stronger fluorescence were sorted using flow cytometry, and further screened by fermentation in a 96-deep-well plate and 500 mL shaker. Results: The fermentation results showed that the L-lysine production was increased by up to 9.7% in the mutant strains with higher fluorescence intensities, and that the highest screening positive rate was 69%, compared with that in the wild-type strain. Conclusion: The application of artificially constructed rare codons in this study represents an efficient, accurate, and simple method for screening other amino acid-producing microorganisms.

Study on the construction technology of ß-alanine synthesizing Escherichia coli based on cellulosome assembly.

Introduction: ß-Alanine is the only ß-amino acid in nature; it is widely used in food additives, medicines, health products, and surfactants. To avoid pollution caused by traditional production methods, the synthesis of ß-alanine has been gradually replaced by microbial fermentation and enzyme catalysis, which is a green, mild, and high-yield biosynthesis method. Methods: In this study, we constructed an Escherichia coli recombinant strain for efficient ß-alanine production using glucose as the raw material. The microbial synthesis pathway of L-lysine-producing strain, Escherichia coli CGMCC 1.366, was modified using gene editing by knocking out the aspartate kinase gene, lysC. The catalytic efficiency and product synthesis efficiency were improved by assembling key enzymes with cellulosome. Results: By-product accumulation was reduced by blocking the L-lysine production pathway, thereby increasing the yield of ß-alanine. In addition, catalytic efficiency was improved by the two-enzyme method to further increase the ß-alanine content. The key cellulosome elements, dockerin (docA) and cohesin (cohA), were combined with L-aspartate-α-decarboxylase (bspanD) from Bacillus subtilis and aspartate aminotransferase (aspC) from E.coli to improve the catalytic efficiency and expression level of the enzyme. ß-alanine production reached 7.439 mg/L and 25.87 mg/L in the two engineered strains. The ß-alanine content reached 755.465 mg/L in a 5 L fermenter. Discussion: The content of ß-alanine synthesized by constructed ß-alanine engineering strains were 10.47 times and 36.42 times higher than the engineered strain without assembled cellulosomes, respectively. This research lays the foundation for the enzymatic production of ß-alanine using a cellulosome multi-enzyme self-assembly system.

Search for key genes, key signaling pathways, and immune cell infiltration in uterine fibroids by bioinformatics analysis.

Uterine fibroids grow in the myometrium and are benign tumors. The etiology and molecular mechanism are not fully understood. Here, we hope to study the potential pathogenesis of uterine fibroids by bioinformatics. Our aim is to search for the key genes, signaling pathways and immune infiltration about the development of uterine fibroids. The GSE593 expression profile was downloaded from the Gene Expression Omnibus database, which contains 10 samples, including 5 uterine fibroids samples and 5 normal controls. Bioinformatics methods were used to find differentially expressed genes (DEGs) in tissues and further analyze the DEGs. R (version 4.2.1) software was used for Kyoto Encyclopedia of Genes and Genomes (KEGG) and Gene Ontology (GO) pathway enrichment analysis of DEGs in uterine leiomyoma tissues and normal control. STRING database was used to generate protein-protein interaction (PPI) networks of key genes. Then, CIBERSORT was used to assess the infiltration of immune cells in uterine fibroids. A total of 834 DEGs were identified, of which 465 were up-regulated and 369 were down-regulated. GO andKEGG pathway analysis showed that the DEGs were mainly concentrated in extracellular matrix and cytokine related signaling pathways. We identified 30 key genes in DEGs from the PPI network. There were some differences in infiltration immunity between the 2 tissues. This study indicated that screening key genes, signaling pathways and immune infiltration by comprehensive bioinformatics analysis is helpful to understand the molecular mechanism of uterine fibroids and provide new insights into understanding the molecular mechanism.