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*

Content of multiple components (neochlorogenic acid,L-tryptophan,vicenin-2,isoquercitrin,and astragalin) in Moringa oleifera leaves was determined by high-performance liquid chromatography (HPLC),and the absolute content-time curves were plotted.Based on Fick's law of diffusion and Higbie's penetration theory,the parameters of the equations were calculated,and the measured results were substituted into the mathematical model to fit the equations.The n and a obtained from the equations on the decocting time factor and the solvent volume were close to each other.The dynamic models of the five components are as follows:■.The variation of the content of multiple components in M.oleifera leaves with time and solvent volume was explored.It was found that the content of the components was the highest when the leaves were decocted for 30 min with solvent volume 12 folds of the medicinal material.The dissolution and destruction of components and the diffusion movement of components are the main causes of the content change of M.oleifera leaves at different time and with different solvent volumes.The R~2of the linear equations on the content and the equations on the decocting process (5-30min and solvent volume 12-20 folds of the medicinal materials) was≥0.999 8 and≥0.9,respectively.Thus,the content determination and the decocting kinetic model had high accuracy,which can reflect the change law of the content of key components in M.oleifera leaves during the decoction.This study is expected to serve as a reference for optimizing the decocting technology.
Kinetics ; Moringa oleifera/chemistry* ; Plant Leaves/chemistry* ; Solvents ; Tryptophan/analysis*

This paper aims to study the difference in the intestinal absorption kinetics of main active components of Sini decoction and its separated recipes and explain the scientificity and rationality of the compatibility of Sini Decoction. A in situ intestinal perfusion rat model was established to evaluate the differences in the absorption of benzoylmesaconine, benzoylaconine, benzoylhypacoitine, mesaconitine, hypaconitine, glycyrrhizic acid, liquiritin and 6-gingerol from Sini Decoction and its separated recipes in the duodenum, jejunum and ileum by high performance liquid chromatography(HPLC). The results indicated that the Sini Decoction group was superior to the Aconiti Lateralis Radix Praeparata group in terms of absorption degree and rate for aconitum alkaloids. The absorption of benzoylmesaconine and hypaconitine in the duodenum, jejunum and ileum was faster and stronger in the Sini Decoction group(P<0.05). The absorption degree of glycyrrhizic acid in the duodenum was significantly higher in the Sini Decoction group than in the Glycyrrhizae Radix et Rhizoma group and the Glycyrrhizae Radix et Rhizoma-Zingiberis Rhizoma group(P<0.05). The absorption rate and degree of 6-gingerol in the ileum in the Sini Decoction group were significantly higher than those in the Zingiberis Rhizoma group(P<0.05). In short, Zingiberis Rhizoma and Glycyrrhizae Radix et Rhizoma can promote the absorption of aconitum alkaloids in different intestinal segments, which reflects the scientific composition of Sini Decoction.
Aconitine/analogs & derivatives* ; Aconitum ; Alkaloids ; Animals ; Catechols ; Drugs, Chinese Herbal ; Fatty Alcohols ; Glycyrrhizic Acid ; Intestinal Absorption ; Kinetics ; Rats

Gut bacterial nitroreductases play an important role in reduction of various nitroaromatic compounds to the corresponding N-nitroso compounds, hydroxylamines or aromatic amines, most of which are carcinogenic and mutagenic agents. Inhibition of gut nitroreductases has been recognized as an attractive approach for reducing mutagen metabolites in the colon, so as to prevent colon diseases. In this study, the inhibitory effects of 55 herbal medicines against Escherichia coli(E. coli) nitroreductase (EcNfsA) were examined. Compared with other herbal extracts, Syzygium aromaticum extract showed superior inhibitory potency toward EcNfsA mediated nitrofurazone reduction. Then, the inhibitory effects of 22 major constituents in Syzygium aromaticum against EcNfsA were evaluted. Compared with other tested natural compounds, ellagic acid, corilagin, betulinic acid, oleanic acid, ursolic acid, urolithin M5 and isorhamnetin were found with strong to moderate inhibitory effect against EcNfsA, with IC₅₀ values ranging from 0.67 to 28.98 mol·L^-1. Furthermore, the inhibition kinetic analysis and docking simulation demonstrated that ellagic acid and betulinic acid potently inhibited EcNfsA (K_i < 2 μmol·L ^-1) in a competitively inhibitory manner, which created strong interactions with the catalytic triad of EcNfsA. In summary, our findings provide new scientific basis for explaining the anti-mutagenic activity of Syzygium aromaticum, where some newly identified EcNfsA inhibitors can be used for developing novel agents to reduce the toxicity induced by bacterial nitroreductase.
Ellagic Acid/pharmacology* ; Escherichia coli ; Kinetics ; Nitroreductases/pharmacology* ; Plant Extracts/pharmacology* ; Syzygium

Between August and September, 2021, this study included 605 SARS-CoV-2 natural infection cases and 589 SARS-CoV-2 breakthrough cases from Nanjing and Yangzhou, as well as 690 inactivated COVID-19 vaccine recipients from Changzhou, China. In SARS-CoV-2 natural infection cases, the age range was 19-91 years (median age: 66 year), and the medians(Q₁,Q₃) of IgG titers were 0.19 (0.06-1.31), 3.70 (0.76-69.48), 15.31 (2.59-82.16), 4.41 (0.99-31.74), 2.31 (0.75-13.83), 2.28 (0.68-9.94) and 2.80 (1.00-9.53) at one to seven weeks after SARS-CoV-2 infection, respectively. In SARS-CoV-2 breakthrough cases, the age range was 18-76 years (median age: 45 year), and the medians(Q₁,Q₃)of IgG titers were 1.93 (0.34-26.67), 38.87 (7.90-121.0), 75.09 (11.85-123.70), 21.97 (5.20-95.58), 13.97 (3.47-46.82), 9.56 (2.48-33.38) and 4.38 (1.87-11.00) at one to seven weeks after SARS-CoV-2 infection, respectively. In inactivated COVID-19 vaccine recipients, the age range was 18-87 years (median age: 47 years), and the medians(Q₁,Q₃)of IgG titers were 16.22 (15.84-33.42), 5.35 (2.96-13.23), 3.30 (2.18-6.18), 3.14 (1.16-5.70), 2.77 (1.50-4.52), 2.72 (1.76-4.36), 2.01 (1.27-3.51) and 1.94 (1.35-3.09) at one to eight months after SARS-CoV-2 infection, respectively. The results suggested that IgG antibodies increased gradually within two weeks after SARS-CoV-2 infection, then declined gradually at three to seven weeks in SARS-CoV-2 natural infection cases. In SARS-CoV-2 breakthrough cases, IgG antibodies increased rapidly within two weeks, then declined gradually at three to seven weeks after SARS-CoV-2 infection. Additionally, IgG antibodies decreased rapidly within three months, then decreased gradually and remained at a low level within three months after immunization.
Humans ; Aged ; Middle Aged ; Young Adult ; Adult ; Aged, 80 and over ; Adolescent ; COVID-19 Vaccines ; COVID-19 ; SARS-CoV-2 ; Kinetics ; Antibodies, Viral ; Immunoglobulin G