Characterization of a marine-derived dextranase and its application to the prevention of dental caries.

The dextranase added in current commercial dextranase-containing mouthwashes is largely from fungi. However, fungal dextranase has shown much higher optimum temperature than bacterial dextranase and relatively low activity when used in human oral cavities. Bacterial dextranase has been considered to be more effective and suitable for dental caries prevention. In this study, a dextranase (Dex410) from marine Arthrobacter sp. was purified and characterized. Dex410 is a 64-kDa endoglycosidase. The specific activity of Dex410 was 11.9 U/mg at optimum pH 5.5 and 45 °C. The main end-product of Dex410 was isomaltotriose, isomaltoteraose, and isomaltopentaose by hydrolyzing dextran T2000. In vitro studies showed that Dex410 effectively inhibited the Streptococcus mutans biofilm growth in coverage, biomass, and water-soluble glucan (WSG) by more than 80, 90, and 95 %, respectively. The animal experiment revealed that for short-term use (1.5 months), both Dex410 and the commercial mouthwash Biotene (Laclede Professional Products, Gardena, CA, USA) had a significant inhibitory effect on caries (p = 0.0008 and 0.0001, respectively), while for long-term use (3 months), only Dex410 showed significant inhibitory effect on dental caries (p = 0.005). The dextranase Dex410 from a marine-derived Arthrobacter sp. strain possessed the enzyme properties suitable to human oral environment and applicable to oral hygiene products.

Establishment of acquired tracheoesophageal fistula using a modified magnetic compression technique in rabbits and its postmodeling evaluation.

BACKGROUND: Previous studies have validated the efficacy of both magnetic compression and surgical techniques in creating rabbit tracheoesophageal fistula (TEF) models. Magnetic compression achieves a 100% success rate but requires more time, while surgery, though less frequently successful, offers rapid model establishment and technical maturity in larger animal models. AIM: To determine the optimal approach for rabbit disease modeling and refine the process. METHODS: TEF models were created in 12 rabbits using both the modified magnetic compression technique and surgery. Comparisons of the time to model establishment, success rate, food and water intake, weight changes, activity levels, bronchoscopy findings, white blood cell counts, and biopsies were performed. In response to the failures encountered during modified magnetic compression modeling, we increased the sample size to 15 rabbit models and assessed the repeatability and stability of the models, comparing them with the original magnetic compression technique. RESULTS: The modified magnetic compression technique achieved a 66.7% success rate, whereas the success rate of the surgery technique was 33.3%. Surviving surgical rabbits might not meet subsequent experimental requirements due to TEF-related inflammation. In the modified magnetic compression group, one rabbit died, possibly due to magnet corrosion, and another died from tracheal magnet obstruction. Similar events occurred during the second round of modified magnetic compression modeling, with one rabbit possibly succumbing to aggravated lung infection. The operation time of the first round of modified magnetic compression was 3.2 ± 0.6 min, which was significantly reduced to 2.1 ± 0.4 min in the second round, compared to both the first round and that of the original technique. CONCLUSION: The modified magnetic compression technique exhibits lower stress responses, a simple procedure, a high success rate, and lower modeling costs, making it a more appropriate choice for constructing TEF models in rabbits.

An evolutionary analysis of the GH57 amylopullulanases based on the DOMON_glucodextranase_like domains.

Thermostable amylopullulanase (TAPU) is valuable in starch saccharification industry for its capability to catalyze both α-1,4 and α-1,6 glucosidic bonds under the industrial starch liquefication condition. The majority of TAPUs belong to glycoside hydrolase family 57 (GH57). In this study, we performed a phylogenetic analysis of GH57 amylopullulanase (APU) based on the highly conserved DOMON_glucodextranase_like (DDL) domain and classified APUs according to their multidomain architectures, phylogenetic analysis and enzymatic characters. This study revealed that amylopullulanase, pullulanase, andα-amylase had passed through a long joint evolution process, in which DDL played an important role. The phylogenetic analysis of DDL domain showed that the GH57 APU is directly sharing a common ancestor with pullulanase, and the DDL domains in some species undergo evolution scenarios such as domain duplication and recombination.

A GH57 family amylopullulanase from deep-sea Thermococcus siculi: expression of the gene and characterization of the recombinant enzyme.

The gene encoding a new extracellular amylopullulanase (type II pullulanase) was cloned from an extremely thermophilic anaerobic archaeon Thermococcus siculi strain HJ21 isolated previously from a deep-sea hydrothermal vent. The functional hydrolytic domain of the amylopullulanase (TsiApuN) and its MalE fusion protein (MTsiApuN) were expressed heterologously. The complete amylopullulanase (TsiApu) was also purified from fermentation broth of the strain. The pullulanase and amylase activities of the three enzymes were characterized. TsiApu had optimum temperature of 95°C for the both activities, while MTsiApuN and TsiApuN had a higher optimum temperature of 100°C. The residual total activities of MTsiApuN and TsiApuN were both 89% after incubation at 100°C for 1 h, while that of TsiApu was 70%. For all the three enzymes the optimum pHs for amylase and pullulanase activities were 5.0 and 6.0, respectively. By analyzing enzymatic properties of the three enzymes, this study suggests that the carboxy terminal region of TsiApu might interfere with the thermoactivity. The acidic thermoactive amylopullulanases MTsiApuN and TsiApuN could be further employed for industrial saccharification of starch.

Study on the Mechanism of Jiawei Shengjiang Powder in Improving Male Asthma-Induced Asthenospermia Based on Network Pharmacology and Bioinformatics.

BACKGROUND: Jiawei Shengjiang Powder (JWSJP) is a classical Chinese medicinal formula, which has been widely applied in the treatment of asthma and complications for many years due to its curative effect. AIM: To verify the effect of JWSJP in improving abnormal sperm motility caused by asthma and to explore its potential mechanism. MATERIALS AND METHODS: The active compounds of JWSJP were obtained from high performance liquid chromatography tandem mass spectrometry and the Traditional Chinese Medicine System Pharmacology. The key active components and targets of JWSJP were predicted based on network pharmacological analysis and bioinformatics research. Rats were randomly divided into normal, model and treatment groups. The rat model of allergic asthma was induced by intraperitoneal injection of ovalbumin solution. The experiment judged improvement of semen quality by evaluating sperm motility, and detected the expression of related proteins in testicular tissue of Sprague-Dawley rats by RT-qPCR and Western blot methods. Hematoxylin and eosin (HE) staining was used to observe the changes in testicular tissue structure in rats. RESULTS: Through the analysis of network pharmacology and bioinformatics, it was found that beta-sitosterol, quercetin, gallic acid, pelargonidin and kaempferol were the key active components of Jiawei Shengjiang Powder. Tumor necrosis factor (TNF), interleukin-6 (IL-6) and insulin (INS) genes are crucial targets of JWSJP in the treatment of spermatogenic dysfunction caused by acute asthma. After 8 weeks of intervention, compared with the model group, the treatment group had significantly improved sperm motility (P < 0.05). There were significant differences in TNF, IL6, and INS proteins in the treatment group, and the HE staining of testicular tissue structure in the treatment group was significantly improved. CONCLUSION: JWSJP can improve the abnormal sperm motility induced by asthma, and its mechanism may be related to the expression of related proteins and mRNA of TNF, IL6, and INS.