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Plastics have brought invaluable convenience to human life since it was firstly synthesized in the last century. However, the stable polymer structure of plastics led to the continuous accumulation of plastic wastes, which poses serious threats to the ecological environment and human health. Poly(ethylene terephthalate) (PET) is the most widely produced polyester plastics. Recent researches on PET hydrolases have shown great potential of enzymatic degradation and recycling of plastics. Meanwhile, the biodegradation pathway of PET has become a reference model for the biodegradation of other plastics. This review summarizes the sources of PET hydrolases and their degradation capacity, degradation mechanism of PET by the most representative PET hydrolase-IsPETase, and recently reported highly efficient degrading enzymes through enzyme engineering. The advances of PET hydrolases may facilitate the research on the degradation mechanism of PET and further exploration and engineering of efficient PET degradation enzymes.
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Humans , Hydrolases/metabolism , Polyethylene Terephthalates/metabolism , Plastics/metabolism , EthylenesABSTRACT
Algae are a large group of photosynthetic organisms responsible for approximately half of the earth's total photosynthesis. In addition to their fundamental ecological roles as oxygen producers and as the food base for almost all aquatic life, algae are also a rich source of bioactive natural products, including several clinical drugs. Cytochrome P450 enzymes (P450s) are a superfamily of biocatalysts that are extensively involved in natural product biosynthesis by mediating various types of reactions. In the post-genome era, a growing number of P450 genes have been discovered from algae, indicating their important roles in algal life-cycle. However, the functional studies of algal P450s remain limited. Benefitting from the recent technical advances in algae cultivation and genetic manipulation, the researches on P450s in algal natural product biosynthesis have been approaching to a new stage. Moreover, some photoautotrophic algae have been developed into "photo-bioreactors" for heterologous P450s to produce high-value added pharmaceuticals and chemicals in a carbon-neutral or carbon-negative manner. Here, we comprehensively review these advances of P450 studies in algae from 2000 to 2021.
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Objective To investigate prevalence and epidemiologic features of Saffold virus (SAFV) in hospitalized children with acute respiratory infection or digestive tract infection Tianjin area. Methods Nasopharyngeal aspirates from children with acute respiratory infection and fecal samples from children with digestive tract infection in Tianjin Children ’s Hospital were collected from January 2013 to December 2013. Viral nucleic acid was extracted, and SAFV infection was determined by using real-time quantitative PCR. Positive PCR products were sequenced. The sequencing results were aligned with known gene sequences of SAFV sequences in GenBank. The positive viral infection rate of nasopharyngeal aspirates and fecal samples, viral positive constituent ratio and positive detection rate in different age groups, seasonal distribution of SAFV infection were calculated. Other common respiratory tract or digestive tract viruses were also detected. Results Fourty-three (11.9%) nasopharyngeal aspirates from children with acute respiratory infection tested positive for SAFV. There was no significant difference between male and female infected children (aged between 6 d and 12 years old). The 79%(34/43) of the patients with SAFV infection aged under 1 year old. The infection most occurred in summer and winter. The 63 (16.4%) fecal samples from children with digestive tract infection tested positive for SAFV. There was significant difference between male and female infected children (aged between 5 h and 11 years old). SAFV infection was found to be year round. There was no significant difference in different age groups of nasopharyngeal aspirates and fecal samples. The mixed infection rate with SAFV and other respiratory tract or digestive tract viruses were 7.0%(3/43)and 12.7%(8/63), respectively. Conclusion Infection of SAFV had occurred in children with acute respiratory infection or digestive tract infection in Tianjin. SAFV has high detection rate in these children and is more common in children aged under 1 year old. The data suggest that some of acute respiratory infection or digestive tract infections in pediatric patients are related to SAFV. The Clinical doctors should pay attention to them .
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BACKGROUND:Effective sorting of prostate cancer stem cels is the basis of experimental studies in prostate cancer developing. The most common sorting method is magnetic-activated cel sorting. OBJECTIVE:To separate CD133+/CD44+ cels in prostate cancer tissues using self-designed magnetic beads folowed by culture, passage and immunological identification. METHODS:Self-designed magnetic microspheres were applied to establish immunomagnetic beads to sort CD133+/CD44+ cels in prostate cancer tissues. The sorted cels were cultured in serum-free medium. The sphere formation, cel morphology, and proliferation ability after cel passage were statisticaly compared between the sorted cels and the normal tumor cel lines. Immunofluorescence detection was performed to detect the expression of specific antibodies. RESULTS AND CONCLUSION:Self-designed immunomagnetic beads had smal diameter and a high-sorting effect. The sorted cels possessed a high capacity of microsphere formation. After cel culture and passage, the cels highly expressed CD133 and CD44 antigens. The sorted cels with no induction had varying shapes and grew vigorously. After induction with transforming growth factor-β, the cultured cels were noted to have a single shape and grow slowly. The cel proliferation ability of sorted cels in these two groups differed significantly from that of the normal cancer cel lines (bothP < 0.05). In conclusion, the CD133+/CD44+ cels sorted from prostate tumor cels possessed cel morphology and function characteristics of stem cels which can provide a basis for extraction and culture of prostate cancer stem cels. Cite this article:Gong R, Li SY, Huo ZX, Ding H, Sun EL. Extraction of prostate cancer stem cels using self-designed magnetic beads. Zhongguo Zuzhi Gongcheng Yanjiu. 2016;20(1):36-41.
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Objective To establish several human umbilical vein endothelial cell ( HUVEC ) strains with over-ex-pression or low expression of receptor for activated C kinase 1 ( RACK1 ) , which will provide an effective tool for future studying the function of RACK1 in arrhythmia.Methods The full-length cDNA sequence of RACK1 gene was amplified and inserted into pIRES2-EGFP.At the same time, designed and synthesised complementary DNA sequences of 3 pairs of short hairpin structure and a pair of negative control sequence , then subcloned into the plas-mid pGenesil-1 .The HUVEC cells were transfected with these plasmids and screened by using G 418 .And the expression of RACK1 mRNA and protein in the cells were assayed by qRT-PCR and Western blot , respectively . Results RACK1 eukaryotic expression vector and siRNA expression vectors of RACK 1 were constructed success-fully.After a 48 h transfection of HUVEC cells with the recombinant vectors and G 418 selection, the positive cell clones were obtained .qRT-PCR and Western blot showed that over-expression vector and interference vectors could effectively enhanced and knocked-down RACK1 expression in HUVEC strains .Conclusions HUVEC cell strains with over-expression and low expression of RACK 1 have been successfully established .
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AIM:To investigate the effects of nodosin extracted from Chinese traditional medicine on the pro-liferation of HepG2 cells cultured in vitro and to detect the protein expression of Bcl-2 and Bax in HepG2 cells.METH-ODS:HepG2 cells were treated with different concentrations (1.25, 2.5, 5, 10 and 20 μmol/L) of nodosin for 24 h. The morphological changes of HepG2 cells were observed under inverted microscope.The inhibitory rates of HepG2 cell growth were detected by MTT assay.The apoptotic rates and the protein expression of Bcl-2 and Bax were analyzed by flow cytometry.RESULTS:Shrunken and suspended HepG2 cells increased with the increases in the concentrations of nodo-sin.The apoptotic rates and the expression of Bax increased with the increases in the doses of nodosin, while the expression of Bcl-2 decreased.CONCLUSION:Nodosin inhibits the growth of HepG2 cells in a dose-dependent manner.The inhibi-tion of HepG2 cell growth is induced by decreasing Bcl-2 and increasing Bax, thus promoting cell apoptosis.
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This study is to investigate the effect of the major chemical composition in rhizome of Pterocypsela elata, lactuside B, on expression of bcl-2, bax mRNA and their protein in rats' cerebral cortex after cerebral ischemia-reperfusion injury. First, middle cerebral artery ischemia-reperfusion injury model was established, and each group was treated with the corresponding medicines. Animals were separately sacrificed at 24 h and 72 h. The brain infarct volumes were detected by TTC dye, bcl-2 and bax mRNA expression was checked by RT-PCR, and the proteins of bcl-2 and bax were explored by two-step immunohistochemistry in cerebral cortex of rats. Lactuside B can reduce brain infarct volume of cerebral cortex of rats, increase the expression of bcl-2 mRNA and decrease that of bax mRNA. Moreover, the ratio of bcl-2 to bax mRNA is higher in 12.5 and 25 mg kg(-1) dose group, respectively, which is significantly different from that of model group (P < 0.05 or P < 0.01). Generally, either 12.5 or 25 mg kg(-1) dose group is better than positive control medicine nimodipine (P < 0.05 or P < 0.01). In addition, the expression of bcl-2 and bax protein is consistent with their gene expression. Infarct volume and the ratio of bcl-2 to bax mRNA expression are significantly different (P < 0.05 or P < 0.01) between 72 h and 24 h group. The results demonstrated that lactuside B could play a good role in resisting cerebral ischemia by upregulating the expression of bcl-2 mRNA and protein and downregulating that of bax mRNA and protein.
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BACKGROUND: Retinitis pigmentosa (RP) is a non-inflammatory, bilaterally progressive, retinal degeneration characterized by loss of photoreceptor cells via an apoptotic mechanism, and it eventually leads to blindness.Research shows that the traditional Chinese medicines of Astragalus has great prospect on blocking the progression of RP disease.OBJECTIVE: To observe the protective effect of Astragalus on N-methylN-nitrosourea (MNU)-induced retinal damage in Sprague-Dawley (SD) rats and provide the optimal treatment for RP in humans.DESIGN: Randomized controlled experiment.SETTING: School of Pharmaceutical Sciences, Xinxiang Medical College.MATERIALS :The experiment was completed in Pharmacological Laboratory of Zhongshan Ophthalmic Centre, Sun Yat-sen University between March to December 2004. Totally 114 female SD rats were purchased from the Animal Center of Zhongshan Medical College, Sun Yat-sen University.MNU was purchased from Sigma Company of America. Astragalus injection was purchased from Chengdu Diao Jiuhong Pharmaceutical Factory (Batch No. Z99060535, 2 mL/ampoule, main ingredient: Astragalus).METHODS: Among 114rats, 30 were for morphometric analysis of retinal layers, 30 were for detection of apoptosis and 54 were for detection of NF-κB p65 activity. All of them were randomly divided into different groups and each group had 6 rats. Astragalus at doses of 2.5, 5 and 10 g/kg were injected intraperitoneally into 47-day rats once a day. Meanwhile, a single intraperitoneal injection of 60 mg/kg MNU was given to 50-day rats in model and Astragalus groups. At different intervals after MNU treatment,the animals were sacrificed. Retinal damage was evaluated based on retinal thickness, the apoptotic index of the photoreceptor cells was detected by TUNEL labeling and the DNA-binding activity of NF-κB p65 was analyzed according to transcription factor assay kit.MAIN OUTCOME MEASURES: Comparison of retinal thickness, apoptotic index and the activity of nuclear NF-κB p65.RESULTS: Totally 114 rats entered the result analysis. Pretreatment with Astragalus could dose-dependently suppress MNU-induced photoreceptor cell loss and decreased the apoptotic index. Astragalus at dose of 10 g/kg also time-dependently up-regulated the activity of nuclear NF-κB p65.However, protective effect of Astragalus on MNU-induced central retinal damage was not found.CONCLUSION: Astragalus partially protects against MNU-induced retinal damage by up-modulating the activity of nuclear NF-κB p65 to inhibit apoptosis of photoreceptor cells in a dose-dependent manner.