ABSTRACT
Phenylalanine ammonia lyase (PAL) can catalyze L-phenylalanine to produce trans-cinnamic acid, which is widely used in the fields of pharmacy, food and agriculture. In particular, phenylalanine ammonia lyase from Anabaena variabilis (AvPAL) is the only protein drug for the treatment of phenylketonuria. However, the poor activity and low stability limit the application in industry of AvPAL. In this study, the key amino acids of substrate-binding cavity in AvPAL were identified by screening the single site saturation mutagenesis library. Subsequently, the impact of replacing M222 with the additional 19 amino acids on activity was also evaluated by site-directed mutagenesis. It was found that the kcat values of mutants M222L and M222V were 90% and 60% higher than that of AvPAL, and the kcat/Km was 1.4 and 1.5 times as that of AvPAL. Molecular docking results revealed that the higher activity of M222L and M222V may be due to the increase of hydrophobicity favorable for the substrate-binding cavity. This study is important for elucidating the structure-function relationship of AvPAL.
ABSTRACT
Objective:To explore the effects of intracoronary application of tirofiban or nicorandil in patients with acute ST-segment elevation myocardial infarction (STEMI) after percutaneous coronary intervention (PCI).Methods:A total of 198 STEMI patients who were admitted to Hefei High-Tech Cardiovascular Hospital during the period from January 2017 to January 2020 were enrolled. They were divided into tirofiban group, nicorandil group and control group by random number table method, with 66 cases in each group. Patients in the tirofiban group, nicorandil group and control group were given tirofiban, nicorandil and 0.9% sodium chloride in coronary artery before PCI, respectively. After surgery, the three groups were given routine drugs. TIMI blood flow grade and TIMI myocardial perfusion grade (TMPG) before and after surgery in the three groups were recorded. The corrected TIMI frame count (cTFC), TIMI myocardial perfusion frame count (TMPFC), peak levels of serum creatine kinase (CK) and creatine kinase isoenzymes (CK-MB) after surgery in the three groups were statistically analyzed. The reperfusion arrhythmias in PCI, severe hypotension and perioperative bleeding, and number of cases with major adverse cardiac events (MACE) within 3 months after surgery in the three groups were recorded.Results:After surgery, number of cases with TIMI blood flow grading at grade 0- 3 in tirofiban group, nicorandil group and control group was (0, 2, 4, 60) cases, (0, 1, 4, 61) cases and (1, 4, 9, 52) cases, respectively. The number of cases with TMPG grading at grade 0- 3 in tirofiban group, nicorandil group and control group was (0, 3, 6, 57)cases, (0, 2, 5, 59) cases and (1, 5, 11, 49) cases, respectively. TIMI blood flow grading and TMPG in tirofiban group and nicorandil group were significantly better than those in control group ( P<0.05), and there was no significant difference between tirofiban group and nicorandil group ( P>0.05). The cTFC, TMPFC, peak level of CK, peak level of CK-MB, incidence of reperfusion arrhythmia and incidence of MACE in tirofiban group, nicorandil group and control group were [(25.32 ± 5.11) frames, (93.84 ± 13.46) frames, (1 095.32 ± 306.36) U/L, (191.81 ± 63.31) U/L, 19.70%, 18.18%], [(25.17 ± 5.38) frame, (94.74 ± 13.17) frame, (1 113.19 ± 385.68) U/L, (189.72 ± 62.22) U/L, 18.18%, 21.21%] and [(29.85 ± 7.63) frames, (101.38 ± 18.52) frames, (1 669.81 ± 537.61) U/L, (341.68 ± 108.57) U/L, 36.36%, 39.39%], respectively. The above indexes in tirofiban group and nicorandil group were significantly lower than those in control group ( P<0.05), and there was no significant difference between tirofiban group and nicorandil group ( P>0.05). Conclusions:Preoperative intracoronary application of tirofiban or nicorandil is conducive to improving myocardial function and micro-circulation disorders in STEMI patients after PCI, which is of positive roles on improving the short-term prognosis of cardiac function.
ABSTRACT
@#Objective: To explore the mechanism of miR-103 targeting PTEN (gene of phosphate and tension homology deleted on chromsome ten) and activating PI3K/AKT signaling pathway to promote dasatinib (DASA) resistance in lung cancer cells. Methods: DASA-resistant tissues and non-resistant tissues (35 samples for each) from patients treated in Department of Thoracic Surgery, the First Affiliated Hospital of Kunming Medical University from April 2014 to January 2018 were collected for this study. Expression of miR-103 was detected in DASA-resistant tissues and cell lines of lung cancer by quantitative Real-time polymerase chain reaction (qPCR). The effect of miR-103 knock-down on the proliferation, invasion and epithelial mesenchymal transition (EMT) ofA549/DASA cells were measured by CCK-8 assay, Transwell and Wb, respectively. Subsequently, the dual luciferase reporter gene assay was used to verify whether PTEN was a target gene of miR-103. CCK-8, Transwell and Wb assay were further used to investigate the effect of miR103 on malignant biological behaviors of A549/DASA cells via regulating PTEN-PI3K/AKT signaling pathway. Results: miR-103 was highly expressed in DASA-resistant tissues andA549/DASAcells (P<0.01). Knockdown of miR-103 significantly inhibited the proliferation, invasion and EMT ofA549/DASAcells (P<0.05 or P<0.01).Additionally, dual luciferase reporter gene assay confirmed that miR103 directly targeted PTEN and down-regulated its expression (P<0.01). Mechanistically, over-expression of miR-103 targeted and down-regulated PTEN to promote cell viability, invasion and EMT via activating PI3K/AKT pathway (P<0.05 or P<0.01), and further up-regulated the DASA-resistance inA549/DASAcells. Conclusion: miR-103/PTEN/PI3K/AKT signaling pathway plays a certain role in regulating DASA resistance of lung cancer, and knockdown of miR-103 expression may reverse the resistance of A549/DASA cells to DASA.
ABSTRACT
The present investigation reports the chemical composition of the Rhus typhina L. stem identified via mass spectrometry and NMR as gallic acid, 1-O-galloyl-β-D-glucose, tryptophan, scopolin, methyl gallate, fustin, quercetin, rutin, and 1,2,3,4,6-penta-O-galloyl-β-D-glucose. The antioxidant properties and the chemical composition contents of the R. typhina L. stem grown in different regions in China were de-termined. To determine the antioxidant activity, a total phenolic content analysis, 2, 2-diphenyl-1-pi-crylhydrazyl radical scavenging activity assay, ferric reducing antioxidant power assay, andβ-carotene linoleic acid model system were conducted. The results showed that the Rhus typhina L. stem possessed high antioxidant capacities due to its high phenolic content. The contents of the nine isolated compounds were determined by UPLC-ESI-MS/MS. The calibration curves of the nine isolated compounds were linear within the concentration range and the average recoveries were high. The result showed that 1-O-galloyl-β-D-glucose, gallic acid, methyl gallate, and 1,2,3,4,6-penta-O-galloyl-β-D-glucose could be the compounds mainly responsible for the antioxidant capacity of the R. typhina L. stem. This reveals that the R. typhina L. stem is a good source of antioxidants.