Hydrophobic substrate binding pocket remodeling of echinocandin B deacylase based on multi-dimensional rational design.

Actinoplanes utahensis deacylase (AAC)-catalyzed deacylation of echinocandin B (ECB) is a promising method for the synthesis of anidulafungin, the newest of the echinocandin antifungal agents. However, the low activity of AAC significantly limits its practical application. In this work, we have devised a multi-dimensional rational design strategy for AAC, conducting separate analyses on the substrate-binding pocket's volume, curvature, and length. Furthermore, we quantitatively analyzed substrate properties, particularly on hydrophilic and hydrophobic. Accordingly, we tailored the linoleic acid-binding pocket of AAC to accommodate the extended long lipid chain of ECB. By fine-tuning the key residues, the resulting AAC mutants can accommodate the ECB lipid chain with a lower curvature binding pocket. The D53A/I55F/G57M/F154L/Q661L mutant (MT) displayed 331 % higher catalytic efficiency than the wild-type (WT) enzyme. The MT product conversion was 94.6 %, reaching the highest reported level. Utilizing a multi-dimensional rational design for a customized mutation strategy of the substrate-binding pocket is an effective approach to enhance the catalytic efficiency of enzymes in handling complicated substrates.

Properties and biotechnological applications of microbial deacetylase.

Deacetylases, a class of enzymes that can catalyze the hydrolysis of acetylated substrates to remove the acetyl group, used in producing various products with high qualities, are one of the most influential industrial enzymes. These enzymes are highly specific, non-toxic, sustainable, and eco-friendly biocatalysts. Deacetylases and deacetylated compounds have been widely applicated in pharmaceuticals, medicine, food, and the environment. This review synthetically summarizes deacetylases' sources, characterizations, classifications, and applications. Moreover, the typical structural characteristics of deacetylases from different microbial sources are summarized. We also reviewed the deacetylase-catalyzed reactions for producing various deacetylated compounds, such as chitosan-oligosaccharide (COS), mycothiol, 7-aminocephalosporanic acid (7-ACA), glucosamines, amino acids, and polyamines. It is aimed to expound on the advantages and challenges of deacetylases in industrial applications. Moreover, it also serves perspectives on obtaining promising and innovative biocatalysts for enzymatic deacetylation. KEYPOINTS: • The fundamental properties of microbial deacetylases of various microorganisms are presented. • The biochemical characterizations, structures, and catalyzation mechanisms of microbial deacetylases are summarized. • The applications of microbial deacetylases in food, pharmaceutical, medicine, and the environment were discussed.

E-cigarette use among middle school students in Hainan Province / 预防医学

Objective@#To investigate of e-cigarette use among middle school students in Hainan Province, so as to provide insights into tobacco control among adolescents.@*Methods@#Students were randomly sampled using a multistage stratified cluster random sampling method from three junior high schools, two high schools and one vocational high school in Hainan Province from July to October, 2021. Participants' basic features, use of e-cigarettes, e-cigarette advertising exposure were collected using the Questionnaire on Tobacco and Alcohol Prevalence among Chinese Adolescents in 2021 prepared by Chinese Center for Disease Control and Prevention. Following data weighting, students' use of e-cigarettes and exposure to e-cigarette advertisements were descriptively analyzed, and factors affecting current use of e-cigarettes were identified using a multivariable logistic regression model.@*Results@#A total of 8 561 questionnaires were allocated, and 8 538 valid questionnaires were recovered, with an effective recovery rate of 99.73%. The respondents included 4 470 boys (52.35%) and 4 068 girls (47.65%), and there 4 367 junior high school students (51.15%), 3 482 high school students (40.78%), and 689 vocational high school students (8.07%). The rate of e-cigarette use was 25.01% and the rate of current e-cigarette use was 4.68%. There were 2 728 respondents with exposure to e-cigarette advertising during the past 30 days, and the number of weighted individuals were 210 932 (32.60%). The route of e-cigarette advertising exposure mainly included point-of-sale (21.59%), stores (13.61%), and shopping websites (9.01%). Multivariable logistic regression analysis identified region (OR=0.610, 95%CI: 0.482-0.772), males (OR=1.332, 95%CI: 1.062-1.669), high school students (OR=0.376, 95%CI: 0.259-0.545), companion smoking (OR=6.645, 95%CI: 4.935-8.948) and advertising exposure (OR=3.229, 95%CI: 2.581-4.040) as factors affecting current use of e-cigarettes. @*Conclusions@#The use of e-cigarettes among middle school students is higher in Hainan Province than the national level, and exposure to e-cigarette advertisements may facilitate use of e-cigarettes. It is necessary to strengthen the supervision of e-cigarettes, strictly restrict e-cigarettes advertisements and promotions.

Chemical behaviors and toxic effects of ametryn during the UV/chlorine process.

Ametryn (AMT), one of the most widely used herbicides in agriculture, has been frequently detected as a micropollutant in many aquatic environments. AMT residue not only pollutes water but also acts as a precursor for the production of disinfection by-products (DBPs). This study systematically investigated the fate of AMT during the UV/chlorine process. It was observed that the combination of UV irradiation and chlorination degraded AMT synergistically. The results of the radical quenching experiments suggested that AMT degradation by the UV/chlorine process involved the participation of UV photolysis, hydroxyl radical (OH) reactions, and reactive chlorine species (RCS) reactions, which accounted for 45.4%, 36.4%, and 14.5% of the degradation, respectively. Moreover, we found that Cl- 2 was an important reactive radical for AMT degradation. The chlorine dose, pH, coexisting anions (Cl- and HCO3-), and natural organic matter (NOM) were found to affect AMT degradation during the UV/chlorine process. Nineteen predominant intermediates/products of AMT degradation during UV/chlorine process were identified, including atrazine. Moreover, the corresponding transformation pathways were proposed, including electron transfer, bond cleavage (C-S, C-N), radical (OH, Cl and Cl- 2) reactions, and subsequent hydroxylation. The toxicity tests with Vibrio fischeri on AMT degradation suggested that more DBPs were generated by UV/chlorine-treated AMT, which possessed higher acute toxicity than AMT did. Although the UV/chlorine process evidently promoted the AMT degradation, optimization of process parameters may reduce the DBP production and merits further investigation.

Occurrence of microcystin-LR in vegetated lagoons used for urban runoff management.

Phytoremediation with aquatic macrophyte has been considered as an eco-friendly technique for controlling harmful cyanobacteria outbreak and proven to be effective. The conventional water quality parameters are frequently measured to evaluate the effectiveness of phytoremediation. However, the concentration of microcystin-leucine-arginine (MC-LR) in different vegetated water still remains uncertain. In this study, the contents of MC-LR in four macrophyte-vegetated lagoons were determined by solid phase extraction and ultra-high-performance liquid chromatography with tandem mass spectrometry technology. Results indicated that MC-LR was found in Nymphaea tetragona lagoon (lagoon-S), Vallisneria spiralis lagoon (lagoon-B) and another Vallisneria spiralis lagoon (lagoon-J). Only in lagoon dominated by Pistia stratiotes L. (lagoon-D), MC-LR concentration was undiscovered regardless of seasonal variation. The levels of MC-LR varied seasonally and were affected by the different vegetated aquatic macrophytes. The results suggest that in addition to conventional physicochemical parameters and indicators of water quality, MC-LR levels should be taken into consideration when the effectiveness of phytoremediation is assessed.

[Comparative study on effects of blood enriching on mouse model of blood deficiency syndrome induced by cyclophosphamide of albiflorin, paeoniflorin on levels of GM-CSF, IL-3 and TNF-α].

OBJECTIVE: To compare the effects and mechanism of blood enriching on mouse model of blood deficiency syndrome induced by cyclophosphamide of albiflorin and paeoniflorin. METHOD: Albiflorin and paeoniflorin were determined by using animal models of blood deficiency syndrome induced by cyclophosphamide. The amount of WBC, RBC, HGB, index of thymus gland and spleen, and the changes of GM-CSF, IL-3 and TNF-α in serum were detected after the treatment. RESULT: Compared with the model group, the amount of WBC in the group of 30 mg x kg(-1) albiflorin and 30 mg x kg(-1) paeoniflorin were increased obviously (P < 0.01). The amount of RBC in the group of 30 mg x kg(-1) albiflorin and 30 mg x kg(-1) paeoniflorin were increased obviously (P < 0.01, P < 0.001), which did not had a significant difference compared with the same dose. The index of thymus gland in the group of 30 mg x kg(-1) albiflorin was superior to the model group (P < 0.01), the difference was significant compared with the same dose of paeoniflorin (P < 0.05). The GM-CSF in serum in all groups of 30 mg x kg(-1) albiflorin, 15 mg x kg(-1) albiflorin, 30 mg x kg(-1) paeoniflorin and 15 mg x kg(-1) paeoniflorin increased obviously (P < 0.01, P < 0.05, P < 0.01, P < 0.05); The IL-3 in serum in both group of 30 mg x kg(-1) albiflorin and 30 mg x kg(-1) paeoniflorin also increased (P < 0.001). The content of TNF-α in group of 30 mg x kg(-1) albiflorin and 30 mg x kg(-1) paeoniflorin were reduced (P < 0.01), which showed the obvious difference compared with the same dose group (P < 0.01). CONCLUSION: Albiflorin had the effect of blood enriching by regulating the immune function, same with the paeoniflorin. The probable mechanism of nourishing blood and liver of Paeoniae Radix Alba was not only the better effect of adjusting the content of TNF-α, but also might act synergistically with paeoniflorin.

[Study on blood enriching effects of γ-ray radiation of paeoniflorin and albiflorin on mouse model of blood deficiency].

OBJECTIVE: To study the blood enriching effects of Paeoniae Radix Rubra and Paeoniae Radix Alba, paeoniflorin and albiflorin on mouse model of blood deficiency caused by γ-ray radiation. METHOD: Build mouse model of blood deficiency induced by γ-ray radiation. Paeoniae Radix Rubra and Paeoniae Radix Alba were given during modeling. The amount of WBC was detected af- ter the treatment. Based on the result of WBC and paeoniflorin content, albiflorin content in Paeoniae Radix Rubra and Paeoniae Radix Alba, the same model and the same method were used to comparatively study the effect of blood enriching of paeoniflorin and albiflorin. RESULT: On the 7th day, the amount of WBC in model mice treated with 2 g x kg(-1) Paeoniae Radix Alba and 2 g x kg(-1) Paeoniae Radix Rubra significantly increased compared with that of model group (P < 0.05). In another experiment with the same model, the amount of WBC in model mice treated with 120 mg x kg(-1) paeoflorin and 120 mg x kg(-1) albiflorin significantly increased (P < 0.05) compared with that of model group on the 7th day. On the 10th day, the amount of WBC in rats treated with 120 mg x kg(-1) paeoflorin increased significantly (P < 0.05) compared with that of model group. Compared with the same dose of paeoniflorin, the amount of WBC in mice treated with albiflorin had no significant difference. CONCLUSION: All Paeoniae Radix Alba, Paeoniae Radix Rubra, paeoniflorin and al- biflorin can raise the amount of WBC and have the effect of enriching blood induced by radiation, while paeoniflorin and albiflorin have a similar result in this model. The result indicated that both paeoniflorin and albiflorin are effective constituents in Paeoniae Radix Alba, and paeoniflorin work as the common effective constituent in both Paeoniae Radix Rubra and Paeoniae Radix Alba.

[Varieties, functions and clinical applications of Chishao and Baishao: a literature review].

According to Chinese Pharmacopoeia (2010ed), Chishao,Paeoniae Radix Rubra and Baishao,Paeoniae Radix Alba are both from the root of Paeonia lactiflora Pall. In recent years, it is known from the studies that Chishao and Baishao must have the resemblance in the chemical composition, but the differences have related to the ecological environment and the processing methods, this makes their functions be different, athough they derive from the same original plants. This review explores the material basis and functions differences based on the analysis of the relationship in Chishao and Baishao on characteristic index function and the genetic background and the analysis of the clinical and pharmacological effects. It may provide more scientific data for identification and establishment of new quality control methods of the Paeoniae Radix Alba and Paeoniae Radix Rubra in the future.

[Comparative study on effects of blood enriching on mouse model of blood deficiency syndrome induced by compound method of bleeding, starved feeding and exhausting of Paeoniae Radix Alba and Paeoniae Radix Rubra, paeoniflorin and albiflorin].

OBJECTIVE: To study the effects of blood enriching on mouse model of blood deficiency syndrome of Paeoniae Radix Alba and Paeoniae Radix Rubra, paeoniflorin and albiflorin. METHOD: Building the mouse model of blood deficiency syndrome induced by compound method of bleeding, starved feeding and exhausting of swimming, extract from Paeoniae Radix Alba and Paeoniae Radix Rubra were given during modeling. The amount of RBC, HGB were detected after the treatment. Based on the amount results of RBC, HGB and the paeoniflorin content, albiflorin content in Paeoniae Radix Alba and Paeoniae Radix Rubra, the same model and the same method were used to comparatively study the effect of blood enriching of paeoniflorin and albiflorin. RESULT: At the 7th day, the amount of RBC and HGB in model mice was significantly increased (P <0. 01) by 2 g kg-1 Paeoniae Radix Alba and 2 g kg-1 Paeoniae Radix Rubra. At the 14th day, the amount of RBC and HGB in model mice was significantly increased (P <0. 01) by 2 g kg-1 Paeoniae Radix Alba. The amount of RBC and HGB in mice treated with Paeoniae Radix Rubra had an increasing trend compared with the same dose of Paeoniae Radix Rubra, but the difference was not significant. In another experiment with the same model, the amount of RBC and HGB in model mice was significantly increased (P<0.01) by 120 mg kg-1 paeoflorin and 120 mg kg-1 albiflorin at the 7th day, meanwhile, 60 mg kg-1 and 30 mg kg-1 albiflorin also increased the amount of RBC and HGB. At the 14th day, 120 mg kg-1 paeoflorin and all doses of albiflorin increased the amount of RBC and HGB. Comepared with that of the same dose of paeoniflorin, the amount of RBC in mice was significantly increased (P <0. 05) by 30 mg kg-1 albiflorin and 120 mg kg-1 albiflorin; the amount of HGB was significantly increased (P <0. 05) by 30 mg kg -1 albiflorin. CONCLUSION: Paeoniae Radix Alba has a better effect of blood enriching than Paeoniae Radix Rubra. Albiflorin is more effective in blood enriching than paeoniflorin. Combining these, it infers that albiflorin involves in the better blood enriching effect of Paeoniae Radix Alba.

Ex vivo expansion of CD34+ and T and NK cells from umbilical cord blood for leukemic BALB/C nude mouse transplantation.

CBSCT with low incidence of GVHD is associated with higher rates of delayed engraftment and relapse compared with other stem cells transplants. The immune-mediated effect of NK and cytotoxic T cells against residual tumor cells was shown to prevent relapse and reinduce remission after bone marrow transplantation. We expanded CD34+ and T and NK cells ex vivo in cord blood with different cytokines combination and transplanted into leukemic BALB/C nude mouse. The results showed significant expansion of MNCs and CD34+ cells. The CD3+ T cells increased in the groups containing cytokines cocktail, especially in the group with IL-7 or IL-2. CD56+ NK cells number increased significantly only in a medium containing IL-2. Of the 20 engrafted BALB/C nude mice, 14 survived after 6 weeks transplantation, and the numbers in each group were from 3 to 4. Human CD3+ cells in the bone marrow of the survived mice were analyzed by flow cytometry and showed existing evidences. RT-PCR was used to detect leukemic fusion bcr/abl gene; all mice that experienced expanded cord blood transplantation could not be found to have expression of fusion bcr/abl gene. These suggest that T, NK cells as well as CD34+ cells could be expanded from CB MNCs in the same medium with the combination of cytokines. The expanded CB MNCs could reconstitute hematopoiesis and eliminate minimal residue leukemia disease in transplanted mice.

Recurrent laryngeal nerve palsy after thyroidectomy with routine identification of the recurrent laryngeal nerve.

BACKGROUND: The aim of this study was to assess the risk of recurrent laryngeal nerve palsy (RLNP) after thyroidectomy with routine identification of the recurrent laryngeal nerve (RLN) during the operation. METHODS: The present study was confined to 521 patients, 348 total lobectomies and 178 total thyroidectomies, treated by the same surgeon. Temporary and permanent RLNP rates were analyzed for patient groups with stratification of primary operation for benign thyroid disease, thyroid cancer, Graves' disease, and reoperation. Measurement of the RLNP rate was based on the number of nerves at risk. Twenty-six RLNs in 20 thyroid cancer patients with intentional sacrifice were excluded from analysis. RESULTS: Forty RLNs (40 patients) developed postoperative RLNP. Complete recovery of RLN function was documented for 35 of the 37 patients (94.6%) whose RLN integrity had been ensured intraoperatively. Recovery from temporary RLNP ranged from 3 days to 4 months (mean, 30.7 days). Overall incidence of temporary and permanent RLNP was 5.1% and 0.9%, respectively. The rates of temporary/permanent RLNP were 4.0/0.2%, 2.0/0.7%, 12.0/1.1%, and 10.8/8.1% for groups classified according to benign thyroid disease, thyroid cancer, Graves' disease, and reoperation, respectively. CONCLUSIONS: Operations for thyroid cancer, Graves' disease, and recurrent goiter demonstrated significantly higher RLNP rates. Invasion of RLN was identified in 19.4% of patients with thyroid cancer. Postoperatively, the RLN recovered in most of the patients without documented nerve damage during the operation. Total lobectomy with routine RLN identification is recommended as a basic procedure in thyroid operations.

Risk of vocal palsy after thyroidecitomy with identification of the recurrent laryngeal nerve.

The purpose of this study was to assess the risk of vocal palsy after thyroidectomy with identification of recurrent laryngeal nerve (RLN) during surgery. In all, 521 patients treated by the same surgeon were enrolled in this study. Temporary and permanent vocal palsy rates were analyzed for patient groups classified according to surgery for primary benign thyroid disease, thyroid cancer, Graves' disease, and reoperation. Measurement of the vocal palsy rate was based on the number of nerves at risk. Twenty-six intentionally sacrificed RLNs were excluded from analysis. Forty patients developed postoperative unilateral vocal palsy. Complete recovery of vocal palsy was documented for 35 of the 37 patients (94.6%) whose RLN integrity had been ensured intraoperatively. Recovery from temporary vocal palsy ranged from 3 days to 4 months (mean, 30.7 days). The overall incidences of temporary and permanent vocal palsy were 5.1% and 0.9%, respectively. The rates of temporary/permanent vocal palsy in groups classified according to underlying disease were 4.0%/0.2% for benign thyroid disease, 2.0%/0.7% for thyroid cancer, 12.0%/1.1% for Graves' disease, and 10.8%/8.1% for reoperation. Surgery for thyroid cancer, Graves' disease, and recurrent goiter were associated with significantly higher vocal palsy rates. Most patients without documented nerve damage during the operation recovered from postoperative vocal palsy. Total lobectomy with routine RLN identification is recommended as a basic procedure in thyroid surgery.

Ancient schwannoma of the infratemporal fossa.

This article describes a case of ancient schwannoma of the infratemporal fossa. Ancient schwannoma is a rare variant of the neurilemmoma, which clinical findings and radiographic features suggest is a slow-growing, benign tumour. Histopathologic features such as hypercellularity with nuclear atypia can make accurate diagnosis of this tumour difficult. The treatment of this tumour is complete resection, and the prognosis is good.