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Triterpenoid saponins are widely used in medicine, health cares, cosmetics, food additives and agriculture because of their unique chemical properties and rich pharmacological activities. UDP-dependent glycosyltransferases (UGTs) are the key enzymes involved in triterpenoid saponin biosynthesis, and play important roles in the diversity of triterpenoid saponin structures and pharmacological activities. This review summarized the UGTs involved in plant triterpenoid saponin biosynthesis based on the sources of UGTs and the types of receptors. Moreover, the application of UGTs in heterologous biosynthesis of triterpenoid saponins based on synthetic biology was also discussed.
Subject(s)
Glycosyltransferases/genetics , Plants , Saponins/chemistry , TriterpenesABSTRACT
Both natural ginsenoside F2 and unnatural ginsenoside 3β,20S-Di-O-Glc-DM were reported to exhibit anti-tumor activity. Traditional approaches for producing them rely on direct extraction from Panax ginseng, enzymatic catalysis or chemical synthesis, all of which result in low yield and high cost. Metabolic engineering of microbes has been recognized as a green and sustainable biotechnology to produce natural and unnatural products. Hence we engineered the complete biosynthetic pathways of F2 and 3β,20S-Di-O-Glc-DM in Saccharomyces cerevisiae via the CRISPR/Cas9 system. The titers of F2 and 3β,20S-Di-O-Glc-DM were increased from 1.2 to 21.0 mg/L and from 82.0 to 346.1 mg/L at shake flask level, respectively, by multistep metabolic engineering strategies. Additionally, pharmacological evaluation showed that both F2 and 3β,20S-Di-O-Glc-DM exhibited anti-pancreatic cancer activity and the activity of 3β,20S-Di-O-Glc-DM was even better. Furthermore, the titer of 3β,20S-Di-O-Glc-DM reached 2.6 g/L by fed-batch fermentation in a 3 L bioreactor. To our knowledge, this is the first report on demonstrating the anti-pancreatic cancer activity of F2 and 3β,20S-Di-O-Glc-DM, and achieving their de novo biosynthesis by the engineered yeasts. Our work presents an alternative approach to produce F2 and 3β,20S-Di-O-Glc-DM from renewable biomass, which lays a foundation for drug research and development.
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Cadinanes are a class of bicyclic sesquiterpenes with complex stereochemistry and broad pharmacological activities, such as antibacterial, anti-inflammatory, and hypoglycemic activities. To date, structurally diverse and bioactive cadinane sesquiterpenes have been isolated and identified from a variety of plants and microorganisms. Moreover, deeper understandings on cadinane sesquiterpene synthases have been made. This article categorized the 124 new cadinanes which were published in the literatures in the past four years (2017-2020) into five structural types, and presented their pharmacological activities. We also illustrated the elucidation of the biosynthetic pathways for typical cadinanes, summarized the research progress on cadinane sesquiterpene synthases. Finally, current challenges and future prospects were proposed and discussed.
Subject(s)
Anti-Inflammatory Agents , Polycyclic Sesquiterpenes , SesquiterpenesABSTRACT
Medicinal natural products derived from plants are usually of low content and difficult to extract and isolate. Moreover, these compounds are structurally complex, making it difficult to obtain them by environmental unfriendly chemical synthesis. Biosynthesis of medicinal natural products through synthetic biology is a novel, environment-friendly and sustainable approach. Taking terpenoids (ginsenosides, paclitaxel, artemisinin, tanshinones), alkaloids (vincristine and morphine), and flavonoids (breviscapine) as examples, this review summarizes the advances of the biosynthetic pathways and synthetic biology strategies of plant-derived medicinal natural products. Moreover, we introduce the key technologies and methods of synthetic biology used in the research of medicinal natural products, and provide future prospects in this area.
Subject(s)
Biological Products , Biosynthetic Pathways , Plants , Synthetic Biology , TerpenesABSTRACT
BmK AngM1 is a long-chain scorpion toxin purified from the venom of Buthus martensii Karsch. It has been reported to exhibit evident analgesic effect and low toxicity, and has the potential to be a novel analgesic drug. The BmKAngM1 gene was transformed into Pichiapastoris GS115. Mut+ and Mut(s) recombinant strains were screened by phenotype and Mut+ recombinant strains were used to detect BmK AngMl gene copy number in the real-time PCR. Expression of BmK AngM1 in the Mut+ recombinant strain was compared with that of the Mut(s) recombinant strain with the same single copy of BmK AngM1 gene under the same condition. The results indicated that the transcription level of BmK AngM1 gene in the Mut(s) recombinant strain was 2.7 fold of that in the Mut recombinant strain in the real-time PCR, and the expression of BmK AngM 1 in the Mut(s) recombinant strain was 1.5 fold of that in the Mut+ recombinant strain. Therefore, Mut(s) recombinant strain showed better ability to express BmK AngM1 than Mut+ recombinant strain.
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Traditional herbal medicines, Panax ginseng, Panax quinquefolium and Panax notoginseng, attract our attention for their extensive and powerful pharmacological activities. Ginsenosides are the main active constituents of these medicinal herbs. The related glycosyltransferases involved in ginsenoside biosynthesis are the key enzymes which catalyze the last important step. Modification of ginsenoside aglycones by glycosyltransferases produces the complexity and diversity of ginsenosides, which have more extensive pharmacological activity. At present, ginsenoside aglycones and compound K have been obtained by synthetic biology. As the last step of ginsenoside biosynthesis, glycosylation of ginsenoside aglycones has been studied intensively in recent years. This review summarizes the basic strategies and research advances in studies on glycosyltransferases involved in ginsenoside biosynthesis, which is expected to lay the theoretical foundation for the in-depth research of biosynthetic pathway of ginsenosides and their production by synthetic biology.
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The cyclization of 2,3-oxidosqualene is the key branch point of ergosterol and triterpenoid biosynthesis. Downregulation of 2,3-oxidosqualene metabolic flux to ergosterol in Saccharomyces cerevisiae may redirect the metabolic flux toward the triterpenoid synthetic pathway. In our study, primers were designed according to erg7 gene sequence of S. cerevisiae. Three fragments including 5' long fragment, 5' short fragment and erg7 coding region fragment were amplified by PCR. 5' long fragment consists of the promoter and a part of erg7 coding region sequence. 5' short fragment consists of a part of promoter and a part of erg7 coding region sequence. These fragments were inserted reversely into pESC-URA to construct antisense expression plasmids. The recombinant plasmids were transformed into S. cerevisiae INVSc1 and recombinant strains were screened on the nutritional deficient medium SD-URA. The erg7 expression level of recombinant strains, which harbored antisense expression plasmid of erg7 coding region, was similar to that of INVScl by semi-quantitative PCR detection. But erg7 expression level of recombinant strains, which harbored 5' long antisense fragment and 5' short antisense fragment, was significantly lower than that of the control. The results of TLC and HPLC showed that the ergosterol content of recombinant strains, which harbored 5' long antisense fragment, decreased obviously. The ergosterol contents of the others were almost equal to that of INVSc1. Lanosterol synthase gene expression was downregulated by antisense RNA technology in S. cerevisiae, which lays a foundation for reconstructing triterpenoid metabolic pathway in S. cerevisiae by synthetic biology technology.
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Pichia pastoris is one of the most important systems used in the field of molecular biology for the expression of recombinant proteins. The system has advantages of high expression, high stability, high secretion, easy high-density fermentation and low cost. Many factors affect the expression of recombinant protein, such as gene copy number, codon usage preference, type of promoter, molecular chaperones, glycosylation, signal peptide and fermentation process. In this review, research advances of the above aspects are summarized, which lay a foundation for improving the expression of recombinant proteins in P. pastoris.
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Aim To study the screening of the nucleo-tide sequences might be affected by α-syn in vitro. Methods The nucleotide sequences were synthesized according to the feature of base composition, and then mixed with the α-syn-GFP. The CD was used to ana-lyse the changes of the peak. Result The peak of the CD changed greatly when the α-syn-GFP mixed with the GC-box like sequence. Conclusion The α-syn-GFP might affect the GC-box like sequence after trans-located into the nuclei. Then, it plays a role in physio-logical and pathological conditions by affecting the reg-ulation of gene expression.
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Objective To evaluate the role of procalcitonin (PCT)in the early diagnosis for hand,foot and mouth disease (HFMD)with bacterial infection.Methods Clinical data of 234 HFMD children who were hospitalized be-tween January and July 2012 were analyzed retrospectively,according to discharge diagnosis,data were divided into simple viral infection group (n=178)and viral associated with bacterial infection group (n=56),and data of 20 healthy children were selected as the control group.Serum PCT,C-reactive protein (CRP)and peripheral white blood cell (WBC)count were compared.Results There was significant difference in the level of PCT,CRP and WBC among three groups (F=381.94,24.18,and 26.46,respectively,all P<0.05).The positive rate of PCT,CRP and WBC among three groups was significantly different(χ2=178.25,38.98,and 71.21,all P<0.05),PCT,CRP and WBC in bacterial infection group(92.86%[52/56],85.71%[48/56],and 87.50%[49/56]respectively)were significantly higher than those of simple viral infection group (3.93%[7/178],62.36%[111/178],and 30.90%[55/178]respectively)and healthy control group (5.00%[1/20],10.00%[2/20],and 5.00%[1/20]respectively).The sensitivity rate of PCT,CRP and WBC was 92.86%,85.71%,and 87.50% respectively,specificity rate was 95.00%,90.00%,and 95.00% respectively.Conclusion The level of PCT has important value for the early diagno-sis of HFMD with bacterial infection,and its accuracy rate and sensitivity are better than CRP and WBC levels.
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Lanosterol synthase is encoded by the erg7 gene and catalyzes the cyclization of 2, 3-oxidosqualene, which is a rate-limiting step of the inherent mevalonate (MVA)/ergosterol metabolic pathway in Saccharomyces cerevisiae. The intermediate 2, 3-oxidosqualene is also the precursor of triterpenoids. Therefore, the cyclization of 2, 3-oxidosqualene is the key branch point of ergosterol and triterpenoids biosynthesis. Down-regulation of 2, 3-oxidosqualene metabolic flux to ergosterol in S. cerevisiae may redirect the metabolic flux toward the triterpenoid synthetic pathway reconstructed by the synthetic biology approach. To construct erg7 knockout cassette harboring the loxP-Marker-loxP element, long primers were designed, which were homologous to the sequences of both erg7 ORF and plasmid pUG66. The cassette was transformed into diploid wild strain INVSc1 by LiAc/SS Carrier DNA/PEG method and then erg7 gene haploid deficient mutant was obtained by homologous recombination. The results of semiquantitative PCR and real-time quantitative PCR revealed that erg7 expression level in erg7 gene haploid deficient mutant is one time lower than that in wild strain. The results of TLC and HPLC showed that the ergosterol content in deficient mutant decreased to 42% of that in wild strain.
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Ginsenosides are the main active components of medicinal herbs including Panax ginseng and Panax quinquefolium, which have potent effects of anti-tumor, anti-inflammatory, antioxidant and apoptosis inhibition. But the low content of ginsenosides limits its development and usage. At present, how to improve the production of ginsenosides by biological technology has been a new research focus. Some advances in the biosynthesis of ginsenosides by tissue culture and biotransformation have been made in recent years. So far at least twenty genes related to the biosynthesis of ginsenosides from Panax genus plants have been cloned and functionally identified, which has laid a good foundation for the study on the synthetic biology of ginsenosides. This review outlines recent advances in several aspects and is expected to provide a theoretical support to the thorough research of the pathway and regulation of ginsenosides biosynthesis.
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Codon bias is an important factor which influences heterologous gene expression. Optimizing codon sequence could improve expression level of heterologous gene. In order to improve the expression level of BmK AngM1 gene encoding the analgesic peptide from Buthus martensii Karsch in Pichia pastoris, the codon-optimized BmK AngM1 gene according to its cDNA sequence and the preference codon usage of P. pastoris were cloned into expression vector pPIC9K and then transformed into P. pastoris. The expersion of recombinant BmK AngM1 (rBmK AngM1) was inducced by methanol in the medium, and the expression level of the optimized BmK AngM1 gene was 3.7 times of the native one. These results suggested that the expression of BmK AngM1 in P. pastoris could be successfully improved by codon optimization.
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Objective To explore the clinical significance of interleukin (IL)- 17 in nasopharyngeal secretions (NPS) and serum of wheezing children under 5 years old. Methods Fifty-three children with recurrent wheezing under 5 years old were divided into wheezing group Ⅰ (with atopic high risks,27 cases)and wheezing group Ⅱ (without atopic high risks, 26 cases) ;20 children without infectious diseases such as hernia and renal calculus were enrolled as control group. After collecting and dealing their NPS and serum,the levels of IL-17 were measured by double-antibody sandwich enzyme-linked immunosorbent assay (ELISA). Results The levels of IL-17 in serum and NPS in wheezing group Ⅰ [(1469.32 ± 978.30),(1473.70 ±974.35) ng/L],and wheezing group Ⅱ [(263.34 ± 131.80), (788.28±132.40) ng/L] were significantly higher than those in control group [(36.48 ± 2.00), (36.45 ± 5.00) ng/L] (P ＜ 0.01 ), and the levels of IL- 17 in wheezing group Ⅰ were higher than those in wheezing group Ⅱ (P ＜ 0.05 ); the expression of IL- 17 in NPS and serum had a positive correlation (r = 0.313,P ＜ 0.05). Conclusion The detections of IL-17 in NPS can be used as laboratory index to distinguish wheezing children who have a tendency to persistent wheezing, and early intervention and treatment should be given.
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OBJECTIVE To strengthen the management of earthquake victims with nosocomial infection,in order to prevent and control the multidrug-resistance transmission,and the nosocomial infection outbreak. METHODS All 77 earthquake victims were under real-time monitoring. RESULTS Of 77 cases,53 were infected (69.74%). From 83 samples,83 pathogenic bacteria were isolated. The Gram-positive cocci were 19 (meticillin-resistant Staphylococcus aureus 3,Meticillin-resistant S. epidermidis 7),58 were Gram-negative bacilli (Acinetobacter baumannii 21,multi-drug resistant strains 10,ESBLs positive Escherichia coli 10,Pseudomonas aeruginosa 9) and the fungi were 6 strains,The resistance rates of Gram-positive cocci to penicillin,ampicillin/sulbactam and cefazolin were 89.47%,68.42% and 89.47%; the resistance rates of Gram-negative bacillis to imipenem,cefoperazone/sulbactam,piperacillin/tazobactam,azithromycin,tobramycin,and cefoxitin were 37.93%,60.34%,48.83%,98.28%,98.28% and 70.69%,respectively. CONCLUSIONS Under the situation of higher infection rate and a serious drug resistance in earthquake area,there are no multidrug-resistance transmissionm and the spread of nosocomiol infection outbreak happened in hospital due to strictly enforced prevention meassures and access real-time monitoring and management,
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OBJECTIVE To know the disinfection efficacy of electrolyzed oxidizing water(EOW) and glutaraldehyde on clinical used gastroscope and enteroscope in our hospital and to analyze their stability and probable harm.METHODS The gastroscope and enteroscope before and after use on randomly selected outpatients and inpatients were examined on their contamination,and the efficacy of EOW was compared with that of glutaraldehyde.RESULTS After using EOW and glutaraldehyde to disinfect the gastroscope and enteroscope the former showed that its killing rate on commonly encountered pathogens for 1 min was 93.75-98.22%,for 3 min was 81.20-89.29%,and for 5 min was 100.00%;the latter showed that its killing rate for 3 min was 81.20-89.29%,for 5 min was 90.38-93.04%,and for 10 min was 99.92-99.96%.EOW was non-irritative to mucosa,and didn′t cause allergic reaction,but its stability was poor.The glutaraldehyle could bring some side effects,such as some allergy,and mucosa stimulation.CONCLUSIONS It only needs 3-5 min for EOW to kill polluted bacteria on gastroscope and enteroscope to attain the disinfection eligibility,but glutaraldehyde needs more than 10 min to get to the disinfection eligibility.The effect of EOW is strong,rapid,active and environment-safe,it is worthy of application,but it must be applied immediately as soon as possible after production.The use of glutaraldehyde must strengthen the measures of personal protection.
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OBJECTIVE To further improve the quality and promote implementation of(disinfection) and isolation(system), in order to reduce hospital infection.METHODS The quality control network is applied to perfect(disinfection) and isolation system and implemented the quality inspection according to standards to promote the(improvement) of management quality.RESULTS According to weak links existent in management to further(improve) the quality of work(analysis) and inspection that implemented,find out the course of implementing in(existent) weak link,improve and realize the disinfection and isolation system in practice.CONCLUSIONS The further improvement of quality in disinfection and isolation system implement is the best way to improve the(hospital) management of disinfection and isolation.
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OBJECTIVE To explore the efficacy of the systemic sanitary monitoring of nosocomial infection(NI) disinfection and sterilization in NI management and performance of related NI standards of Ministry of Health in hospital.METHODS To review and treat statistically spot sampling results in 12 seasons from 2004 to 2006,and to observe performance of continued improvement after taking measures.RESULTS The qualified rate of 1647 samples including autoclave sterilizer,sterilized pack,sterilized endoscope and attachment,solution for dialysis and 2% glutaraldehyde solution was 100% from 2004 to 2006;3411 bacteriological monitoring samples of air,surface of object,hands etc and 1284 samples of all kinds of disinfectants were monitored.The annual statistical results of above mentioned samples were significantly different(?2=4.11-27.37,P
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As an emerging discipline,the development of medicine verification with sanitary verification direction promotes the convergence of China's public health cause and the international’ s powerfully. Associated with our experience in teaching practice,we grope after the best way to foster students’innovative capability and promote this discipline’s development in the aspects of course content,curriculum system,experimental tuition,practical capability etc.
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From teaching design principle, the article has discussed the key element of the process of hygiene examination teaching designs, and has brought forward three kinds of rational science design process patterns.