This study explored the drying kinetics of Salviae Miltiorrhizae Radix et Rhizoma(SM), established the suitable models simulating the drying kinetics, and then analyzed the dynamic changes of active components during the drying processes with different methods, aiming to provide a basis for the establishment of suitable drying methods and the quality control of SM. The drying kinetics were studied based on the drying curve, drying rate, moisture effective diffusion coefficient, and drying activation energy, and the appropriate drying kinetics model of SM was established. The drying performance of different methods, such as hot air drying, infrared drying, and microwave drying of SM was evaluated, and the changes in the content of 10 salvianolic acids and 6 tanshinones during drying were analyzed by UPLC-TQ-MS. The Technique for Order Preference by Similarity to an Ideal Solution(TOPSIS) was employed to evaluate the quality of SM dried with different methods. The results showed that the drying rate and moisture effective diffusion coefficient of SM increased with the rise in drying temperature, and the maximum drying rates of different methods were in the order of microwave drying > infrared drying > hot air drying, slice > whole root. The drying rate decreased with the rise in temperature and the extension of drying time. The activation energy of hot air drying was higher than that of infrared drying in SM. The most suitable model for simulating the drying process of SM was the Page model. The TOPSIS results suggested infrared drying at 50 ℃ was the optimal drying method for SM. During the drying process, the content of salvianolic acids increased in different degrees with the loss of moisture, among which salvianolic acid B showed the largest increase of 44 times compared with that in the fresh medicinal material. Tanshinones also existed in the fresh herb of SM, and the content of tanshinone Ⅱ_A increased by 3 times after drying. The results provided a basis for the establishment of suitable drying methods and the quality control of SM.
Salvia miltiorrhiza/chemistry* ; Desiccation/methods* ; Drugs, Chinese Herbal/chemistry* ; Rhizome/chemistry* ; Kinetics ; Quality Control ; Abietanes

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*

S-methyl-L-cysteine sulfoxide (SMCO) is a non-protein sulfur-containing amino acid with a variety of functions. There are few reports on the enzymes catalyzing the biosynthesis of SMCO from S-methyl-L-cysteine (SMC). In this study, the flavin-containing monooxygenase gene derived from Schizosaccharomyces pombe (spfmo) was heterologously expressed in Escherichia coli BL21(DE3) and the enzymatic properties of the expressed protein were analyzed. The optimum catalytic conditions of the recombinant SpFMO were 30 ℃ and pH 8.0, under which the enzyme activity reached 72.77 U/g. An appropriate amount of Mg²⁺ improved the enzyme activity. The enzyme kinetic analysis showed that the K_m and k_cat/K_m of SpFMO on the substrate SMC were 23.89 μmol/L and 61.71 L/(min·mmol), respectively. Under the optimal reaction conditions, the yield of SMCO synthesized from SMC catalyzed by SpFMO was 12.31% within 9 h. This study provides reference for the enzymatic synthesis of SMCO.
Schizosaccharomyces/genetics* ; Escherichia coli/metabolism* ; Recombinant Proteins/metabolism* ; Cysteine/biosynthesis* ; Mixed Function Oxygenases/metabolism* ; Schizosaccharomyces pombe Proteins/metabolism* ; Oxygenases/metabolism* ; Kinetics

The metabolic reactions in cells, whether spontaneous or enzyme-catalyzed, form a highly complex metabolic network closely related to cellular physiological metabolic activities. The reconstruction of cellular physiological metabolic network models aids in systematically elucidating the relationship between genotype and growth phenotype, providing important computational biology tools for precisely characterizing cellular physiological metabolic activities and green biomanufacturing. This paper systematically introduces the latest research progress in different types of cellular physiological metabolic network models, including genome-scale metabolic models (GEMs), kinetic models, and enzyme-constrained genome-scale metabolic models (ecGEMs). Additionally, our paper discusses the advancements in the automated construction of GEMs and strategies for condition-specific GEM modeling. Considering artificial intelligence offers new opportunities for the high-precision construction of cellular physiological metabolic network models, our paper summarizes the applications of artificial intelligence in the development of kinetic models and enzyme-constrained models. In summary, the high-quality reconstruction of the aforementioned cellular physiological metabolic network models will provide robust computational support for future research in quantitative synthetic biology and systems biology.
Metabolic Networks and Pathways/physiology* ; Models, Biological ; Artificial Intelligence ; Systems Biology ; Kinetics ; Cell Physiological Phenomena ; Computational Biology ; Synthetic Biology ; Humans

In neurons and myocytes, selective ion channels in the plasma membrane play a pivotal role in transducing chemical or sensory stimuli into electrical signals, underpinning neural and cardiac functionality. Recent advancements in biomedical research have increasingly spotlighted the interaction between ion channels and electromagnetic fields, especially terahertz (THz) radiation. This review synthesizes current findings on the impact of THz radiation, known for its deep penetration and non-ionizing properties, on ion channel kinetics and membrane fluid dynamics. It is organized into three parts: the biophysical effects of THz exposure on cells, the specific modulation of ion channels by THz radiation, and the potential pathophysiological consequences of THz exposure. Understanding the biophysical mechanisms underlying these effects could lead to new therapeutic strategies for diseases.
Neurons/metabolism* ; Animals ; Ion Channels/radiation effects* ; Humans ; Terahertz Radiation ; Kinetics ; Cell Membrane/radiation effects*

Phosphoprotein Phosphatases ; Kinetics ; Protein Phosphatase 2/metabolism*

Genistein and its monoglucoside derivatives play important roles in food and pharmaceuticals fields, whereas their applications are limited by the low water solubility. Glycosylation is regarded as one of the effective approaches to improve water solubility. In this paper, the glycosylation of sophoricoside (genistein monoglucoside) was investigated using a cyclodextrin glucosyltransferase from Penibacillus macerans (PmCGTase). Saturation mutagenesis of D182 from PmCGTase was carried out. Compared with the wild-type (WT), the variant D182C showed a 13.42% higher conversion ratio. Moreover, the main products sophoricoside monoglucoside, sophoricoside diglucoside, and sophoricoside triglucoside of the variant D182C increased by 39.35%, 56.05% and 64.81% compared with that of the WT, respectively. Enzymatic characterization showed that the enzyme activities (cyclization, hydrolysis, disproportionation) of the variant D182C were higher than that of the WT, and the optimal pH and temperature of the variant D182C were 6 and 40℃, respectively. Kinetics analysis showed the variant D182C has a lower K_m value and a higher k_cat/K_m value than that of the WT, indicating the variant D182C has enhanced affinity to substrate. Structure modeling and docking analysis demonstrated that the improved glycosylation efficiency of the variant D182C may be attributed to the increased interactions between residues and substrate.
Cyclodextrins ; Genistein ; Glucosyltransferases/metabolism* ; Glycosylation ; Kinetics

The present study explored the kinetics and variation of volatile components of Atractylodis Macrocephalae Rhizoma during the hot-air drying process to obtain the optimal process parameters under multiple goals such as drying efficiency and drying quality. The dry basis moisture content and drying rate curves along with the change of drying time of Atractylodis Macrocephalae Rhizoma were investigated at five levels of drying air temperatures(30, 40, 50, 60, and 70 ℃). The relationship between moisture ratio and time in the drying process of Atractylodis Macrocephalae Rhizoma was fitted and verified by Midilli model, Page model, Overhults model, Modified Page model, Logaritmic model, Two terms Exponential model, and Newton model. Meanwhile, the effective diffusion coefficient of moisture(D_(eff)) and activation energy(E_a) in Atractylodis Macrocephalae Rhizoma were calculated under different drying air temperatures. GC-MS was used to determine the volatile components and content changes of the fresh Atractylodis Macrocephalae Rhizoma and dried products at different temperatures. The dry basis moisture content and drying rate of Atractylodis Macrocephalae Rhizoma were closely related to the temperature of the drying medium, and the moisture of the Atractylodis Macrocephalae Rhizoma decreased with the prolonged drying time. As revealed by the drying rate curve, the drying rate increased with the increase in hot air temperature, and the migration of moisture was accelerated. The comparison of the correlation coefficient(R~2), chi-square(χ~2), and root mean standard error(RMSE) of each model indicated that the parameter average of the Midilli model had the highest degree of fit, with R~2=0.999 2, χ~2=8.78×10~(-5), and RMSE=8.20×10~(-3). Besides, the D_(eff) at 30-70 ℃ was in the range of 1.04×10~(-9)-6.28×10~(-9) m~2·s~(-1), and E_a was 37.47 kJ·mol~(-1). The volatile components of fresh Atractylodis Macrocephalae Rhizoma and dried products at different temperatures were determined by GC-MS, and 18, 18, 18, 17, 17, and 18 compounds were identified respectively, which accounted for more than 84.76% of the volatile components. In conclusion, the hot-air drying of Atractylodis Macrocephalae Rhizoma can be model-fitted and verified and the variation law of the moisture and volatile components of Atractylodis Macrocephalae Rhizoma with temperature is obtained. This study is expected to provide new ideas for exploring the drying characteristics and quality of aromatic Chinese medicine.
Atractylodes ; Drugs, Chinese Herbal ; Hot Temperature ; Kinetics ; Rhizome

In this study, low-field nuclear magnetic resonance(LF-NMR) and magnetic resonance imaging(MRI) were employed to analyze the water distribution, status, and migration in the moistening process of Arecae Semen. Peleg model was adopted to study the water absorption kinetics of Arecae Semen moistened at different water temperatures(10, 30, and 50 ℃). The Arecae Semen samples soaked at different water temperatures all contained four water states: binding water T_(21), non-flowing water T_(22), free water T_(23), and unbound water T_(24). Non-flowing water had the largest increase in peak area during the moistening process, followed by free water. The peak areas of non-flowing water, free water, and total water were correlated with the water content(P<0.01). Therefore, LF-NMR can quickly and non-destructively predict the water content of Arecae Semen during moistening. The peak area of non-flowing water and the content of free water were correlated with the content of arecoline in the soaking solution(P<0.01), which indicated that the faster flow of non-flowing water and more free water corresponded to more arecoline dissolved. The MRI images showed that the water migration pathway varied at different soaking temperatures, and the moistening degree obtained by this means was consistent with that obtained based on traditional experience. The rate constant K_1 fitted by Peleg model decreased with the increase in water temperature, while the capacity constant K_2 showed an opposite trend. The Arrhenius equation fitting of K_1 with temperature showed that the activation energy of Arecae Semen in the moistening process was 32.98 kJ·mol~(-1). LF-NMR/MRI can be used to analyze the water status and content and determine the end moisturing point of Arecae Semen. Peleg model can accurately describe the water absorption properties of Arecae Semen in the moistening process. The findings of this study can guide the moistening optimization and mechanism research of other seed Chinese medicinal materials.
Areca ; Arecoline/analysis* ; Drugs, Chinese Herbal/analysis* ; Kinetics ; Seeds/chemistry* ; Water/analysis*

OBJECTIVE: To analyze the kinetic characteristics of lymphocyte subsets and myeloid-derived suppressor cell (MDSC) in patients who newly diagnosed intermediate- to high-risk aGVHD and treated with steroids-ruxolitinib as the first line therapy from a single-arm, open clinical trial (NCT04061876). METHODS: We prospectively observed the efficacy of 23 patients having intermediate- to high-risk aGVHD and treated with steroids-ruxolitinib as the first line therapy. The kinetic characteristics of lymphocyte subsets and MDSC were monitored, and then we compared them in steroids-ruxolitinib group (n=23), free-aGVHD group (n=20) and steroids group (n=23). RESULTS: Of the 23 patients, the CR rate was 78.26% (18/23) on day 28 after first-line treatment with steroids-ruxolitinib. On day 28 after treatment, patients had lower level of CD4⁺CD29⁺ T cells (P=0.08) than that of pre-treatment, whereas levels of other lymphocyte subsets in this study were higher than that of pre-treatment; CD4⁺CD29⁺ T cells in CR patients decreased, compared with refractory aGVHD patients. On day 28 of treatment, CD8⁺CD28^- T cells (P=0.03) significantly increased in patients with aGVHD than that in patients without aGVHD, so did CD8⁺CD28^- T / CD8⁺CD28⁺ T cell ratio (P=0.03). Compared with patients without aGVHD, patients with aGVHD had lower level of G-MDSC, especially on day 14 after allo-HSCT (P=0.04). Compared with pre-treatment, M-MDSC was higher in CR patients on day 3 and 7 post-treatment (P₃=0.01, P₇=0.03), e-MDSC was higher on day 28 post-treatment (P=0.01). Moreover, compared with CR patients, M-MDSC was lower in refractory aGVHD patients on day 3 post-treatment (P=0.01) and e-MDSC was lower on day 28 post-treatment (P=0.01). Compared with steroids group, MDSC in steroids-ruxolitinib group was higher, with the most significant difference in M-MDSC (P₃=0.0351; P₇=0.0142; P₁₄=0.0369). CONCLUSION We found that patients newly diagnosed intermediate- to high-risk aGVHD receiving first-line therapy with steroids-ruxolitinib achieved high response rate. Moreover, the novel first-line therapy has a small impact on the immune reconstitution of patients after allo-HSCT. Elevated MDSC might predict a better response in aGVHD patients receiving this novel first-line therapy. M-MDSC responded earlier to steroids-ruxolitinib than e-MDSC, G-MDSC.
Graft vs Host Disease ; Hematopoietic Stem Cell Transplantation ; Humans ; Kinetics ; Myeloid-Derived Suppressor Cells ; Nitriles ; Pyrazoles ; Pyrimidines ; Retrospective Studies ; Steroids