To screen and identify a chitosanase with high stability, we cloned the chitosanase gene from Bacillus atrophaeus with a high protease yield from the barren saline-alkali soil and expressed this gene in Escherichia coli. The expressed chitosanase of B. atrophaeus (BA-CSN) was purified by nickel-affinity column chromatography. The properties including optimal temperature, optimal pH, substrate specificity, and kinetic parameters of BA-CSN were characterized. The results showed that BA-CSN had the molecular weight of 31.13 kDa, the optimal temperature of 55 ℃, the optimal pH 5.5, and good stability at temperatures below 45 ℃ and pH 4.0-9.0. BA-CSN also had good stability within 4 h of pH 3.0 and 10.0, be activated by K⁺, Na⁺, Mn²⁺, Ca²⁺, Mg²⁺, and Co²⁺, (especially by Mn²⁺), and be inhibited by Fe³⁺, Cu²⁺, and Ag⁺. BA-CSN showcased the highest relative activity in the hydrolysis of colloidal chitosan, and it had good hydrolysis ability for colloidal chitin. Under the optimal catalytic conditions, BA-CSN demonstrated the Michaelis constant K_m and maximum reaction rate V_max of 9.94 mg/mL and 26.624 μmoL/(mL·min), respectively, for colloidal chitosan. In short, BA-CSN has strong tolerance to acids and alkali, possessing broad industrial application prospects.
Bacillus/genetics* ; Hydrogen-Ion Concentration ; Escherichia coli/metabolism* ; Glycoside Hydrolases/biosynthesis* ; Substrate Specificity ; Enzyme Stability ; Chitosan/metabolism* ; Temperature ; Kinetics ; Cloning, Molecular ; Bacterial Proteins/biosynthesis* ; Recombinant Proteins/genetics*

Objective: To establish a progressive research strategy for “colonic components analysis - efficacy verification and mechanism exploration - gut microbiota”, screen pharmacodynamic substances, and investigate their mechanism via gut microbiota. Methods: The pharmacodynamics of Gegen Qinlian decoction (GQD) were assessed using a mouse model of dextran sulfate sodium-induced ulcerative colitis (UC). Ultra-performance liquid chromatography-quadrupole-orbitrap mass spectrometer was used to identify the prototype and metabolic components of GQD in the colon during UC. To analyze the structure and function of characteristic genera of GQD and its active components, 16S rRNA sequencing was performed. Results: We identified 67 prototypic and 14 metabolic components of GQD in the UC colon. The primary prototype components are flavonoids and alkaloids, including puerarin (PUE), baicalin (BAI), and berberine (BER). The metabolism was predominantly sulfonation. Efficacy verification showed that the main active components, puerarin, baicalin, and berberine, had good therapeutic effects on UC. The results of 16S rRNA gene sequencing showed that GQD improved UC by regulating the structure and function of the gut microbiota. The abundance of gut microbiota involved in the metabolism of the prototype components was influenced by the corresponding components. The function prediction results showed that PUE was the most comparable to GQD, with 24 consistent pathways. BAI and BER showed comparable gut microbiota regulation pathways. Characteristic pathways of BER include glucometabolic processes. Conclusion This study focused on the key issues in the gut microbiota pathway and developed a progressive research strategy to understand the transformation mechanisms of colonic components. This research systematically analyzed the active components and metabolic transformation of GQD in the colon during the pathological state of UC, as well as changes in the structure and function of the gut microbiota, clarified the mechanism of GQD and its active components in improving UC via the gut microbiota pathway.

Objective To determine the effect of baicalein on high glucose-induced cardiac fibro-blast pyroptosis based on the nucleotide-binding oligomerization domain-like receptor protein 3(NLRP3)/cysteinyl aspartate-specific proteinase-1(Caspase-1)/gasdermin D(GSDMD)pathway.Methods Rat cardiac fibroblasts were grouped into control,high glucose group,low-,medium-and high-dose baicalein(H-,M-and L-baicalein)groups,and H-baicalein+NLRP3 agonist(BMS-986299)group.Except for the control group,all other groups were cultured in DMEM medium containing 40 mmol/L glucose,then 12.5,25 and 50 μmol/L baicalein was added into the medium correspondingly,and 1 μmol/L BMS-986299 was used to treat the H-baicalein+NLRP3 agonist group.Lactate dehydrogenase(LDH)cytotoxicity assay were employed to detect cell cytotoxicity.qRT-PCR and Western blotting were performed to determine the expression of NLRP3,Caspase-1,and GSDMD at mRNA and protein levels.Results High glucose treatment induced more EdU positive cells,higher pyroptotic rate,stronger cytotoxicity,higher Col-Ⅰ and Col-Ⅲ contents,and enhanced mRNA and protein levels of NLRP3,Caspase-1 and GSDMD in comparison to the control group(P＜0.05).The H-baicalein+NLRP3 agonist group had more EdU positive cells(26.85±2.95 cells vs 15.43±1.82 cells,P＜0.05),higher pyroptotic rate[(33.45±4.02)％vs(17.34±2.15)％,P＜0.05],stronger cytotoxicity[(27.94±2.93)％vs(14.13±1.87)％,P＜0.05],and increased contents of Col-Ⅰ(107.58±13.39 ng/ml vs 58.73±8.36 ng/ml,P＜0.05)and Col-Ⅲ(118.43±13.95 ng/ml vs 68.74±8.57 ng/ml,P＜0.05),and enhanced expression of NLRP3,Caspase-1 and GSDMD at both mRNA and protein levels(P＜0.05)when compared with the H-baicalein group.Conclusion Baicalein inhibits high glucose-induced cardiac fibroblast pyroptosis by suppressing NLRP3/Caspase-1/GSDMD pathway.

Objective To evaluate the role of dynamic contrast-enhanced magnetic resonance imaging(DCE-MRI)in the diagnosis of axillary lymph node metastasis(ALNM)in breast cancer patients with low HER-2 expression.Methods A total of 297 breast cancer patients with low HER-2 expression treated at the Affiliated Hospital of Xuzhou Medical University were enrolled and divided into ALNM group(n=71)and non-ALNM group(n=226)according to whether there was ALNM.All patients underwent DCE-MRI,and DCE-MRI derived parameters were collected and analyzed.Logistic regression analysis was used to identify the risk factors for ALNM,and the efficacy of DCE-MRI in diagnosing ALNM was assessed using receiver operating characteristic curve.Results Significant differences were observed between two groups in lesion distribution,TNM staging,vascular invasion,and most DCE-MRI derived parameters including short-to-long axis ratio,Ve,Ktrans,Kep,ADC and SER(all P<0.05).Multivariate regression analysis revealed that the short-to-long axis ratio,Ve,Ktrans,Kep,ADC and SER were significant risk factors for ALNM in breast cancer patients.Comparative analysis demonstrated that the combination of DCE-MRI derived parameters yielded a maximum area under the curve of 0.976,with a sensitivity of 91.5%and a specificity of 92.9%.Conclusion DCE-MRI is an effective tool for determining the presence of ALNM in breast cancer patients with low HER-2 expression,providing significant diagnostic evidence for clinical practice.

Objective To determine the effect of baicalein on high glucose-induced cardiac fibro-blast pyroptosis based on the nucleotide-binding oligomerization domain-like receptor protein 3(NLRP3)/cysteinyl aspartate-specific proteinase-1(Caspase-1)/gasdermin D(GSDMD)pathway.Methods Rat cardiac fibroblasts were grouped into control,high glucose group,low-,medium-and high-dose baicalein(H-,M-and L-baicalein)groups,and H-baicalein+NLRP3 agonist(BMS-986299)group.Except for the control group,all other groups were cultured in DMEM medium containing 40 mmol/L glucose,then 12.5,25 and 50 μmol/L baicalein was added into the medium correspondingly,and 1 μmol/L BMS-986299 was used to treat the H-baicalein+NLRP3 agonist group.Lactate dehydrogenase(LDH)cytotoxicity assay were employed to detect cell cytotoxicity.qRT-PCR and Western blotting were performed to determine the expression of NLRP3,Caspase-1,and GSDMD at mRNA and protein levels.Results High glucose treatment induced more EdU positive cells,higher pyroptotic rate,stronger cytotoxicity,higher Col-Ⅰ and Col-Ⅲ contents,and enhanced mRNA and protein levels of NLRP3,Caspase-1 and GSDMD in comparison to the control group(P＜0.05).The H-baicalein+NLRP3 agonist group had more EdU positive cells(26.85±2.95 cells vs 15.43±1.82 cells,P＜0.05),higher pyroptotic rate[(33.45±4.02)％vs(17.34±2.15)％,P＜0.05],stronger cytotoxicity[(27.94±2.93)％vs(14.13±1.87)％,P＜0.05],and increased contents of Col-Ⅰ(107.58±13.39 ng/ml vs 58.73±8.36 ng/ml,P＜0.05)and Col-Ⅲ(118.43±13.95 ng/ml vs 68.74±8.57 ng/ml,P＜0.05),and enhanced expression of NLRP3,Caspase-1 and GSDMD at both mRNA and protein levels(P＜0.05)when compared with the H-baicalein group.Conclusion Baicalein inhibits high glucose-induced cardiac fibroblast pyroptosis by suppressing NLRP3/Caspase-1/GSDMD pathway.

Objective To evaluate the role of dynamic contrast-enhanced magnetic resonance imaging(DCE-MRI)in the diagnosis of axillary lymph node metastasis(ALNM)in breast cancer patients with low HER-2 expression.Methods A total of 297 breast cancer patients with low HER-2 expression treated at the Affiliated Hospital of Xuzhou Medical University were enrolled and divided into ALNM group(n=71)and non-ALNM group(n=226)according to whether there was ALNM.All patients underwent DCE-MRI,and DCE-MRI derived parameters were collected and analyzed.Logistic regression analysis was used to identify the risk factors for ALNM,and the efficacy of DCE-MRI in diagnosing ALNM was assessed using receiver operating characteristic curve.Results Significant differences were observed between two groups in lesion distribution,TNM staging,vascular invasion,and most DCE-MRI derived parameters including short-to-long axis ratio,Ve,Ktrans,Kep,ADC and SER(all P<0.05).Multivariate regression analysis revealed that the short-to-long axis ratio,Ve,Ktrans,Kep,ADC and SER were significant risk factors for ALNM in breast cancer patients.Comparative analysis demonstrated that the combination of DCE-MRI derived parameters yielded a maximum area under the curve of 0.976,with a sensitivity of 91.5%and a specificity of 92.9%.Conclusion DCE-MRI is an effective tool for determining the presence of ALNM in breast cancer patients with low HER-2 expression,providing significant diagnostic evidence for clinical practice.

Objective:To observe any effect of using a lower limb exoskeleton robot during ankle rehabilitation training on the walking ability of stroke survivors.Methods:Forty-five persons with cerebral apoplexy were randomly divided into a control group, a robot group and a combination group, each of 15. In addition to routine rehabilitation training 5 days a week for 3 weeks, the robot group additionally trained for 10 minutes assisted by a lower limb exoskeleton. The combined group joined that training and additionally undertook 10 minutes of ankle rehabilitation training. Before and after the experiment all of the participants were evaluated using the Fugl-Meyer lower extremity scale (FMA-LE), the Holden functional walking scale (FAC), and for walking speed and step frequency.Results:After treatment, significant improvement was observed in the average FMA-LE score, FAC grade, walking speed and step frequency in all 3 groups. The robot group′s average FMA-LE score, walking speed and step frequency were then significantly better than those of the control group ( P<0.05). Moreover, the average FMA-LE score, step speed and step frequency of the combined group after treatment were (22.67±1.63) min, (0.65±0.05) m/s and (80.80±4.28) steps /min, respectively, significantly better than the other two groups ( P<0.05). Conclusion:Using an exoskeleton robot combined with ankle rehabilitation training can significantly improve the walking of stroke survivors.

Methamphetamine(METH)is a new type of abused drug with a strong central stimulant effect.Its excitatory pathway involves a series of central higher-level functions,including drug-related rewards and motivation,learning and memory,decision-making,and execution.METH not only causes neurotoxicity,but its long-term use may also cause cognitive dysfunction,loss of personality,and may lead to serious social violence in addicts.Exosomes,as a novel cell-to-cell carrier,are involved in the occurrence and development of drug addiction,and exosome microRNAs are important biomarkers for METH addiction and are also involved in various aspects of METH-induced neurotoxicity.Eoxosmes may thus be useful therapeutic carriers providing a new approach for the diagnosis and treatment of METH abuse.

Methamphetamine(METH)is a new type of abused drug with a strong central stimulant effect.Its excitatory pathway involves a series of central higher-level functions,including drug-related rewards and motivation,learning and memory,decision-making,and execution.METH not only causes neurotoxicity,but its long-term use may also cause cognitive dysfunction,loss of personality,and may lead to serious social violence in addicts.Exosomes,as a novel cell-to-cell carrier,are involved in the occurrence and development of drug addiction,and exosome microRNAs are important biomarkers for METH addiction and are also involved in various aspects of METH-induced neurotoxicity.Eoxosmes may thus be useful therapeutic carriers providing a new approach for the diagnosis and treatment of METH abuse.