Pyrosequencing of the Camptotheca acuminata transcriptome reveals putative genes involved in camptothecin biosynthesis and transport

Background: Camptotheca acuminata is a Nyssaceae plant, often called the "happy tree", which is indigenous in Southern China. C. acuminata produces the terpenoid indole alkaloid, camptothecin (CPT), which exhibits clinical effects in various cancer treatments. Despite its importance, little is known about the transcriptome of C. acuminata and the mechanism of CPT biosynthesis, as only few nucleotide sequences are included in the GenBank database.Results: From a constructed cDNA library of young C. acuminata leaves, a total of 30,358 unigenes, with an average length of 403 bp, were obtained after assembly of 74,858 high quality reads using GS De Novo assembler software. Through functional annotation, a total of 21,213 unigenes were annotated at least once against the NCBI nucleotide (Nt), non-redundant protein (Nr), Uniprot/SwissProt, Kyoto Encyclopedia of Genes and Genomes (KEGG), and Arabidopsis thaliana proteome (TAIR) databases. Further analysis identified 521 ESTs representing 20 enzyme genes that are involved in the backbone of the CPT biosynthetic pathway in the library. Three putative genes in the upstream pathway, including genes for geraniol-10-hydroxylase (CaPG10H), secologanin synthase (CaPSCS), and strictosidine synthase (CaPSTR) were cloned and analyzed. The expression level of the three genes was also detected using qRT-PCR in C. acuminata. With respect to the branch pathway of CPT synthesis, six cytochrome P450s transcripts were selected as candidate transcripts by detection of transcript expression in different tissues using qRT-PCR. In addition, one glucosidase gene was identified that might participate in CPT biosynthesis. For CPT transport, three of 21 transcripts for multidrug resistance protein (MDR) transporters were also screened from the dataset by their annotation result and gene expression analysis.Conclusion: This study produced a large amount of transcriptome data from C. acuminata by 454 pyrosequencing. According to EST annotation, catalytic features prediction, and expression analysis, novel putative transcripts involved in CPT biosynthesis and transport were discovered in C. acuminata. This study will facilitate further identification of key enzymes and transporter genes in C. acuminata

Study on Surface Hardness and Microstructure of Pure Copper Chip Strips Prepared by LSEM

Large strain extrusion machining (LSEM) is one of the severe plastic deformation (SPD) methods that can improve the mechanical properties of materials. The purpose of this experiment is to study the surface hardness and microstructure of the pure copper chip strips. It was found that most of the grains of the chip strips had been refined to the ultrafine grain grade. Finite element analysis (FEA) simulations were conducted to predict the von Mises equivalent strains. Based on the analysis of variance (ANOVA), further study indicated that the surface hardness of the chip strips was decided by several key parameters including the chip thickness compression ratio, rake angle, and uncut chip thickness during LSEM. Through this analysis, a set of parameters which have the greatest impact on the properties of the material can be found. This set of parameters helps us to achieve the strip with the best performance.</jats:p

Study on Surface Hardness and Microstructure of Pure Copper Chip Strips Prepared by LSEM

Large strain extrusion machining (LSEM) is one of the severe plastic deformation (SPD) methods that can improve the mechanical properties of materials. The purpose of this experiment is to study the surface hardness and microstructure of the pure copper chip strips. It was found that most of the grains of the chip strips had been refined to the ultrafine grain grade. Finite element analysis (FEA) simulations were conducted to predict the von Mises equivalent strains. Based on the analysis of variance (ANOVA), further study indicated that the surface hardness of the chip strips was decided by several key parameters including the chip thickness compression ratio, rake angle, and uncut chip thickness during LSEM. Through this analysis, a set of parameters which have the greatest impact on the properties of the material can be found. This set of parameters helps us to achieve the strip with the best performance

Safety and efficiency of stem cell therapy for COVID-19: a systematic review and meta-analysis

Abstract Background With the COVID-19 pandemic continuing, various treatments have become widely practiced. Stem cells have a wide range of applications in the treatment of lung diseases and have therefore been experimentally used to treat patients with COVID-19, but whether the expanded use of stem cells is safe and reliable still lacks enough evidence. To address this issue, we systematically reviewed the safety and efficiency of stem cell therapy in COVID-19 cases. Methods We searched PubMed, Embase, Web of Science, The Cochrane Library, CNKI, WanFang, VIP and SinoMed up to January 18, 2022. The included studies were assessed using the Risk-of-bias tool 1.0 and MINORS instrument. The adverse events, mortality, length of hospital day and laboratory parameters were analyzed by meta-analysis. We adhered to PRISMA reporting guideline. Results We have included 17 studies meeting the inclusion data. There were no significant differences in AEs (OR = 0·39, 95% CI = 0·12 to 1·33, P = 0·13, I2 = 58%) and SAEs (OR = 0·21, 95% CI = 0·04 to 1·03, P = 0·05, I2 = 0%) between stem cell therapy group and control group. The analysis showed that stem cell treatment could significantly reduce the mortality rate(OR = 0·24, 95% CI = 0·13 to 0·45, P &lt; 0·01, I2 = 0%), but was not able to cause changes in length of hospital stay or most laboratory parameters. Conclusions The present study shows that stem cell therapy for COVID-19 has a remarkable effect on efficiency without increasing risks of adverse events and length of hospital stay. It is potentially necessary to establish the criteria for COVID-19 for stem cell therapy. </jats:sec

Additional file 7 of Safety and efficiency of stem cell therapy for COVID-19: a systematic review and meta-analysis

Additional file 7. Serious Adverse Events. All serious adverse events reported in involved studies between experimental and control groups

Additional file 5 of Safety and efficiency of stem cell therapy for COVID-19: a systematic review and meta-analysis

Additional file 5. Characteristics of Involved Studies. Specific information of 17 articles included: country, study design, number of patients, treatment of intervention group and control group

Additional file 6 of Safety and efficiency of stem cell therapy for COVID-19: a systematic review and meta-analysis

Additional file 6. All Adverse Events in Involved Studies. All adverse events (AEs), AEs related to treatment and numbers of patients with AEs reported in involved studies between experimental and control groups

Additional file 3 of Safety and efficiency of stem cell therapy for COVID-19: a systematic review and meta-analysis

Additional file 3. Quality Assessment of 10 RCTs. 10 RCTs included in the systematic review were assessed for literature quality using the Risk-of-bias Tool 1.0. a: Risk of bias graph: authors' judgements’ about each risk of bias item presented as percentages. b: Risk of bias summary: authors' judgements about each risk of bias item

Additional file 2 of Safety and efficiency of stem cell therapy for COVID-19: a systematic review and meta-analysis

Additional file 2. List of excluded studies. 176 studies were excluded after reviewing the full texts. Detailed information of these articles are shown