ABSTRACT
Informed consent is one of the key elements to protect the rights and welfare of the patients or research subjects. With the development of electronic information technology, the diversity and convenience brought by the electronization makes the electronic informed consent (E-Consent) come into being. European and American countries have begun to apply E-Consent in the field of clinical trials, established a relatively perfect E-Consent platform and software system, and initially formed the guiding principles and recommendations of E-Consent. However, the implementation of E-Consent is still less in China, and there is no targeted legal basis and guidelines for ethical review. Therefore, this paper explored the implementation potential of E-Consent domestically by analyzing the application scenarios, advantages and disadvantages, and feasibility of E-Consent, and tried to establish the practical ethic review points of E-Consent based on the basic principles of ethical principles, to ensure that clinical trials have an appropriate E-Consent process.
ABSTRACT
Organic acids are organic compounds that can be synthesized using biological systems. They often contain one or more low molecular weight acidic groups, such as carboxyl group and sulphonic group. Organic acids are widely used in food, agriculture, medicine, bio-based materials industry and other fields. Yeast has unique advantages of biosafety, strong stress resistance, wide substrate spectrum, convenient genetic transformation, and mature large-scale culture technology. Therefore, it is appealing to produce organic acids by yeast. However, challenges such as low concentration, many by-products and low fermentation efficiency still exist. With the development of yeast metabolic engineering and synthetic biology technology, rapid progress has been made in this field recently. Here we summarize the progress of biosynthesis of 11 organic acids by yeast. These organic acids include bulk carboxylic acids and high-value organic acids that can be produced naturally or heterologously. Finally, future prospects in this field were proposed.
Subject(s)
Saccharomyces cerevisiae/metabolism , Organic Chemicals , Carboxylic Acids/metabolism , Metabolic Engineering , Fermentation , AcidsABSTRACT
Research-oriented hospitals are the currently development direction of large hospitals, and their research ethics management has played an important role in China’s scientific and technological innovation and clinical research development through years of practice. However, at present, China’s overall scientific and technology ethics governance framework system is still incomplete, governance authority is insufficient, ethics committee members lack ethical professional technical training, and the awareness and understanding of science and technology ethics among medical staff still need to be improved, which indicates that the level of technology ethics governance in research-oriented hospitals needs to be improved. It is suggested to improve from the aspects of regulatory system, governance responsibilities, training of ethical practitioners, supervision and punishment measures, and ethical education of scientific and technological research talents, so as to better protect subjects and promote the construction of scientific and technological ethics in the research-oriented hospitals.
ABSTRACT
Extended clinical trials are medical treatment activity based on the humanitarianism to provide new medical products during the clinical trials for specific patients who have no other effective medical means to prolong life or alleviate pain. Extensive clinical trials have both medical and scientific attributes, which are significantly different from registered clinical trials and require special ethical attention. At present, the extended clinical trials in China are still in the initial stage, laws, regulations and supporting management methods are not perfect, and there is a lack of experience in ethical governance of such special clinical trials. This paper took the expanded clinical trial of medical devices as an example, referred to the current laws and regulations at home and abroad, analyzed their characteristics, and put forward some suggestions on the ethical governance of the whole process of the expanded clinical trials of medical devices in China,including special concerns in the application and acceptance, the first review approval strategy and the key points in continuing review.
ABSTRACT
Acetic acid is a common inhibitor present in lignocellulosic hydrolysate. Development of acetic acid tolerant strains may improve the production of biofuels and bio-based chemicals using lignocellulosic biomass as raw materials. Current studies on stress tolerance of yeast Saccharomyces cerevisiae have mainly focused on transcription control, but the role of transfer RNA (tRNA) was rarely investigated. We found that some tRNA genes showed elevated transcription levels in a stress tolerant yeast strain. In this study, we further investigated the effects of overexpressing an arginine transfer RNA gene tR(ACG)D and a leucine transfer RNA gene tL(CAA)K on cell growth and ethanol production of S. cerevisiae BY4741 under acetic acid stress. The tL(CAA)K overexpression strain showed a better growth and a 29.41% higher ethanol productivity than that of the control strain. However, overexpression of tR(ACG)D showed negative influence on cell growth and ethanol production. Further studies revealed that the transcriptional levels of HAA1, MSN2, and MSN4, which encode transcription regulators related to stress tolerance, were up-regulated in tL(CAA)K overexpressed strain. This study provides an alternative strategy to develop robust yeast strains for cellulosic biorefinery, and also provides a basis for investigating how yeast stress tolerance is regulated by tRNA genes.
Subject(s)
Acetic Acid , DNA-Binding Proteins/metabolism , Fermentation , Leucine , RNA, Transfer/genetics , Saccharomyces cerevisiae/metabolism , Saccharomyces cerevisiae Proteins/metabolism , Transcription FactorsABSTRACT
Trichoderma reesei Rut-C30 is widely used in industrial cellulase production, and development of cellulase hyper-producer is of great importance for economic lignocellulosic biorefinery. In this study, T. reesei Rut-C30 was engineered with an artificial zinc finger proteins (AZFPs) library. Two mutants T. reesei M1 and M2 with improved cellulase production were obtained. Compared to the parent strain, the filter paper activity (FPase) of T. reesei M1 and M2 increased 100% and 53%, respectively. In addition, the total amount of extracellular protein from the M1 mutant increased 69%, whereas the endo-β-glucanase (CMCase) activity of the M2 mutant is 64% higher compared to the parental strain. Furthermore, RT-qPCR analysis showed that the major cellulase genes exhibited significantly increased expression in both mutants, but different patterns were observed in the two mutants. On the other hand, the cellulase transcriptional repressor ace1 was down-regulated in both mutants, but the transcription level of the activator xyr1 was only up-regulated in the strain M1. These results demonstrated that different AZFPs exert diverse regulatory mechanisms on cellulase production in T. reesei. Analysis of the target genes of AZFPs from T. reesei M1 and M2 will not only benefit further exploration of the regulatory mechanisms of cellulase biosynthesis in T. reesei, but also enable development of cellulase hyper-producing strains by metabolic engineering.
Subject(s)
Cellulase , Gene Library , Transcription Factors , Trichoderma , Zinc FingersABSTRACT
OBJECTIVE： To establish the method for content determination of the related substance in fudosteine raw material and its preparations. METHODS： Fudosteine or its preparations produced by 8 domestic enterprises were taken as samples. HPLC method （external standard） was used to determine the contents of impurities A， B and C. The separation was performed on MGⅡ C18 column with mobile phase consisted of 0.12％ sodium hexane sulfonate solution （pH 2.0） at flow rate of 1.0 mL/min. The detection wavelength was set at 210 nm， column temperature was 35 ℃ and sample size was 20 μL. The contents of impurities E， F， G were determined by HPLC method （principal component self-contrast method with correction factor）. The separation was performed on Altech Altima C18 column with mobile phase consisted of 0.05 mol/L phosphate buffer-acetonitrile- water （gradient elution） at the flow rate of 0.5 mL/min. The detection wavelength was set at 200 nm， and the column temperature was 30 ℃. The sample size was 20 μL. RESULTS： The linear ranges of impurity A， B， C， E， F and G were 0.446-22.291， 0.202-20.158， 0.101-12.082， 0.111 0-11.100， 0.210 4-10.520， 0.221 6-11.080 μg/mL， respectively. The limits of detection were 5.57， 1.01， 1.99， 2.22， 4.21， 4.43 ng， respectively. The limits of quantitation were 11.14， 2.02， 3.98， 4.45， 8.42， 8.85 ng， respectively. The relative correction factors of impurities E， F and G were 0.91， 1.42 and 1.73， respectively； their relative retention time were 0.88， 1.95 and 3.08. RSDs of precision （n＝6） and stability [impurity A （4 h，n＝3）， other impurities （24 h，n＝7）] tests were all lower than 2.0％. The average recoveries were 98.0％， 97.3％， 102.4％， 99.4％， 98.9％， 96.4％， respectively； RSDs were 1.4％， 1.5％， 1.1％， 0.9％， 1.2％， 0.5％ （n＝9）， respectively. Total contents of substances in fudosteine raw material or its preparation produced by 8 enterprises were all lower than 1.1％. CONCLUSIONS： Established method is sensitive and specific. The method can be used for the quantitative study on related substances in fudosteine raw material and its preparations．
ABSTRACT
Production of bioenergy and bio-based chemicals by using fermentable sugars released from low-cost renewable lignocellulosic biomass has received great attention. Efficient cellulolytic enzymes are crucial for lignocellulose bioconversion, but high cellulase production cost is limiting the bioconversion efficiency of cellulosic biomass and industrial applications of lignocellulose biorefinery. Studies on induction and regulation of cellulase in filamentous fungi will help to further develop superior fungal strains for efficient cellulase production and reduce cellulase production cost. With the advances in high-throughput sequencing and gene manipulation technology using fungal strains, an in-depth understanding of cellulase induction and regulation mechanisms of enzyme expression has been achieved. We reviewed recent progresses in the induction and regulation of cellulase expression in several model filamentous fungi, emphasizing sugar transporters, transcription factors and chromatin remodeling. Future prospects in application of artificial zinc finger proteins for cellulase induction and regulation in filamentous fungi were discussed.
ABSTRACT
Microalgae have been identified as promising candidates for biorefinery of value-added molecules. The valuable products from microalgae include polyunsaturated fatty acids and pigments, clean and sustainable energy (e.g. biodiesel). Nevertheless, high cost for microalgae biomass harvesting has restricted the industrial application of microalgae. Flocculation, compared with other microalgae harvesting methods, has distinguished itself as a promising method with low cost and easy operation. Here, we reviewed the methods of microalgae harvesting using flocculation, including chemical flocculation, physical flocculation and biological flocculation, and the progress and prospect in bio-flocculation are especially focused. Harvesting microalgae via bio-flocculation, especially using bio-flocculant and microalgal strains that is self-flocculated, is one of the eco-friendly, cost-effective and efficient microalgae harvesting methods.
Subject(s)
Biofuels , Biomass , Flocculation , MicroalgaeABSTRACT
Zinc-finger proteins have been widely studied due to their highly conserved structures and DNA-binding specificity of zinc-finger domains. However, researches on the zinc-finger proteins from microorganisms, especially those from prokaryotes, are still very limited. This review focuses on the latest progress on microbial zinc-finger proteins, especially those from prokaryotes and the application of artificial zinc-finger proteins in the breeding of robust strains. Artificial zinc-finger proteins with transcriptional activation or repression domain can regulate the global gene transcription of microbial cells to acquire improved phenotypes, such as stress tolerance to heat, ethanol, butanol, and osmotic pressure. Using the zinc-finger domain as DNA scaffold in the construction of enzymatic system can enhance the catalytic efficiency and subsequently the production of specific metabolites. Currently, zinc-finger domains used in the construction of artificial transcription factor are usually isolated from mammalian cells. In the near future, novel transcription factors can be designed for strain development based on the natural zinc-finger domains from different microbes, which may be used to regulate the global gene expression of microbial cells more efficiently.
Subject(s)
Bacteria , Metabolism , DNA , Chemistry , Protein Engineering , Transcription Factors , Chemistry , Transcriptional Activation , Zinc FingersABSTRACT
Industrial microorganisms are subject to various stress conditions, including products and substrates inhibitions. Therefore, improvement of stress tolerance is of great importance for industrial microbial production. Acetic acid is one of the major inhibitors in the cellulosic hydrolysates, which affects seriously on cell growth and metabolism of Saccharomyces cerevisiae. Studies on the molecular mechanisms underlying adaptive response and tolerance of acetic acid of S. cerevisiae benefit breeding of robust strains of industrial yeast for more efficient production. In recent years, more insights into the molecular mechanisms underlying acetic acid tolerance have been revealed through analysis of global gene expression and metabolomics analysis, as well as phenomics analysis by single gene deletion libraries. Novel genes related to response to acetic acid and improvement of acetic acid tolerance have been identified, and novel strains with improved acetic acid tolerance were constructed by modifying key genes. Metal ions including potassium and zinc play important roles in acetic acid tolerance in S. cerevisiae, and the effect of zinc was first discovered in our previous studies on flocculating yeast. Genes involved in cell wall remodeling, membrane transport, energy metabolism, amino acid biosynthesis and transport, as well as global transcription regulation were discussed. Exploration and modification of the molecular mechanisms of yeast acetic acid tolerance will be done further on levels such as post-translational modifications and synthetic biology and engineering; and the knowledge obtained will pave the way for breeding robust strains for more efficient bioconversion of cellulosic materials to produce biofuels and bio-based chemicals.
Subject(s)
Acetic Acid , Pharmacology , Genomics , Industrial Microbiology , Saccharomyces cerevisiae , GeneticsABSTRACT
Chromosomal integration enables stable phenotype and therefore has become an important strategy for breeding of industrial Saccharomyces cerevisiae strains. pAUR135 is a plasmid that enables recycling use of antibiotic selection marker, and once attached with designated homologous sequences, integration vector for stable expression can be constructed. Development of S. cerevisiae strains by metabolic engineering normally demands overexpression of multiple genes, and employing pAUR135 plasmid, it is possible to construct S. cerevisiae strains by combinational integration of multiple genes in multiple sites, which results in different ratios of expressions of these genes. Xylose utilization pathway was taken as an example, with three pAUR135-based plasmids carrying three xylose assimilation genes constructed in this study. The three genes were sequentially integrated on the chromosome of S. cerevisiae by combinational integration. Xylose utilization rate was improved 24.4%-35.5% in the combinational integration strain comparing with that of the control strain with all the three genes integrated in one location. Strain improvement achieved by combinational integration is a novel method to manipulate multiple genes for genetic engineering of S. cerevisiae, and the recombinant strains are free of foreign sequences and selection markers. In addition, stable phenotype can be maintained, which is important for breeding of industrial strains. Therefore, combinational integration employing pAUR135 is a novel method for metabolic engineering of industrial S. cerevisiae strains.
Subject(s)
Genetic Engineering , Methods , Genetic Vectors , Metabolic Engineering , Plasmids , Genetics , Saccharomyces cerevisiae , Genetics , Xylose , MetabolismABSTRACT
Ethanol tolerance is related to the expression of multiple genes, and genome-based engineering approaches are much more efficient than manipulation of single genes. In this study, ultraviolet (UV) mutagenesis, dielectric barrier discharge (DBD) air plasma mutagenesis, and artificial transcription factor (ATF) technology were adopted to treat an industrial yeast strain S. cerevisiae Sc4126 to obtain mutants with improved ethanol tolerance. Mutants with high ethanol tolerance were obtained, and the ratio of positive mutants was compared. Among the three approaches, the rate of positive mutation obtained by ATF technology was 10- to 100-folds of that of the two other methods, with highest genetic stability, suggesting the ATF technology promising for rapid alteration of phenotypes of industry yeast strains for efficient ethanol fermentation.
Subject(s)
Adaptation, Physiological , Drug Resistance, Fungal , Genetics , Ethanol , Pharmacology , Fungal Proteins , Genetics , Metabolism , Industrial Microbiology , Methods , Mutagenesis , Saccharomyces cerevisiae , GeneticsABSTRACT
Breeding of robust industrial Saccharomyces cerevisiae strains with high ethanol tolerance is of great significance for efficient fuel ethanol production. Zinc finger proteins play important roles in gene transcription and translation, and exerting control on the regulation of multiple genes. The sequence and localization of the zinc finger motif can be designed and engineered, and the artificial zinc finger protein can be used to regulate celluar metabolism. Stress tolerance of microbial strains is related to multiple genes. Therefore, it is possible to use artificially-designed zinc finger proteins to breed stress tolerant strains. In this study, a library containing artificial zinc finger protein encoding genes was transformed into the model yeast strain S288c. A recombinant strain named M01 with improved ethanol tolerance was obtained. The plasmid in M01 was isolated, and then transformed into the industrial yeast strain Sc4126. Ethanol tolerance of the recombinant strain of Sc4126 were significantly improved. When high gravity ethanol fermentation using 250 g/L glucose was performed, comparing with the wild-type strain, fermentation time of the recombinant strain was decreased by 24 h and the final ethanol concentration was enhanced by 6.3%. The results of this study demonstrate that artificial zinc finger proteins are able to exert control on stress tolerance of yeast strains, and these results provide basis to construct robust industrial yeast strains for efficient ethanol fermentation.
Subject(s)
Adaptation, Physiological , Drug Resistance, Fungal , Genetics , Ethanol , Pharmacology , Fungal Proteins , Genetics , Metabolism , Industrial Microbiology , Mutation , Genetics , Peptide Library , Saccharomyces cerevisiae , Genetics , Zinc FingersABSTRACT
Directed evolution of transcription factors can be employed to effectively improve the phenotypes which are controlled by multiple genetic loci. In this study, we used error-prone PCR for the directed evolution of SPT3, which is the component of yeast Spt-Ada-Gcn5-acetyltransferase (SAGA) complex responsible for the transcription of stress-related genes, and studied its effect on the improvement of ethanol tolerance. Mutant library was constructed by ligating the error-prone PCR products with a modified pYES2.0 plasmid, and the expression plasmids were subsequently transformed to yeast industrial strain Saccharomyces cerevisiae 4126. One mutant strain M25 showing superior growth in presence of 10% ethanol was selected. M25 produced 11.7% more ethanol than the control strain harboring the empty vector when 125 g/L glucose was used as substrate. This study revealed that SPT3 is an important transcription factor for the metabolic engineering of yeast ethanol tolerance.
Subject(s)
Directed Molecular Evolution , Methods , Drug Resistance, Fungal , Drug Tolerance , Ethanol , Metabolism , Pharmacology , Industrial Microbiology , Methods , Saccharomyces cerevisiae , Genetics , Metabolism , Saccharomyces cerevisiae Proteins , Genetics , Trans-Activators , Genetics , Transcription Factors , GeneticsABSTRACT
Biofuels are renewable and environmentally friendly, but high production cost makes them economically not competitive, and the development of robust strains is thus one of the prerequisites. In this article, strain improvement studies based on the information from systems biology studies are reviewed, with a focus on their applications on stress tolerance improvement. Furthermore, the contribution of systems biology, synthetic biology and metabolic engineering in strain development for biofuel production is discussed, with an expectation for developing more robust strains for biofuel production.
Subject(s)
Biofuels , Genetic Engineering , Methods , Industrial Microbiology , Methods , Lignin , Metabolism , Saccharomyces cerevisiae , Genetics , Metabolism , Physiology , Synthetic Biology , Methods , Systems Biology , MethodsABSTRACT
Improving stress tolerance of the microbial producers is of great importance for the process economy and efficiency of bioenergy production. Key genes influencing ethanol tolerance of brewing yeast can be revealed by studies on the molecular mechanisms which can lead to the further metabolic engineering manipulations for the improvement of ethanol tolerance and ethanol productivity. Trahalose shows protective effect on the cell viability of yeast against multiple environmental stress factors, however, further research is needed for the exploration of the underlying molecular mechanisms. In this study, the promoter region of the trehalose-6-phosphate synthase gene TPS1 was cloned from the self-flocculating yeast Saccharomyces cerevisiae flo, and a reporter plasmid based on the expression vector pYES2.0 on which the green fluorescence protein EGFP was directed by the TPS1 promoter was constructed and transformed to industrial yeast strain Saccharomyces cerevisiae ATCC4126. Analysis of the EGFP expression of the yeast transformants in presence of 7% and 10% ethanol revealed that the P(TPS1) activity was strongly induced by 7% ethanol, showing specific response to ethanol stress. The results of this study indicate that trehalose biosynthesis in self-flocculating yeast is a protective response against ethanol stress.
Subject(s)
Base Sequence , Cloning, Molecular , Ethanol , Metabolism , Pharmacology , Glucosyltransferases , Genetics , Molecular Sequence Data , Promoter Regions, Genetic , Genetics , Saccharomyces cerevisiae , Genetics , Metabolism , Stress, Physiological , PhysiologyABSTRACT
Directed evolution, which is also called molecular evolution, or artificial evolution, combines random mutagenesis and directed selection. In previous studies, it has been extensively applied for the improvement of enzyme catalytic properties and stability, as well as the expanding of substrate specificity. In recent years, directed evolution was also employed in metabolic engineering of promoters for improving their strength and function, and the engineering of global transcription machinery. These techniques contribute to breeding more tolerant strains against environmental stress, as well as strains with improved fermentation efficiency. In this article, we reviewed the applications of directed evolution in the metabolic engineering of promoters and global transcription machinery. These techniques enabled fine-tuning of gene expression and simultaneous alternation of multiple gene transcription inside the cells, and thus are powerful new tools for metabolic engineering.
Subject(s)
Directed Molecular Evolution , Genetic Engineering , Industrial Microbiology , Methods , Metabolism , Promoter Regions, Genetic , Genetics , Saccharomyces cerevisiae , Genetics , Transcription, Genetic , GeneticsABSTRACT
Improvement of stress tolerance to various adverse environmental conditions (such as toxic products, high temperature) of the industrial microorganisms is important for industrial applications. Ethanol produced by yeast fermentation is inhibitory to both yeast cell growth and metabolisms, and consequently is one of the key stress elements of brewer's yeast. Research on the biochemical and molecular mechanism of the tolerance of yeast can provide basis for breeding of yeast strain with improved ethanol tolerance. In recent years, employing global gene transcriptional analysis and functional analysis, new knowledge on the biochemical and molecular mechanisms of yeast ethanol tolerance has been accumulated, and novel genes and biochemical parameters related to ethanol tolerance have been revealed. Based on these studies, the overexpression and/or disruption of the related genes have successfully resulted in the breeding of new yeast strains with improved ethanol tolerance. This paper reviewed the recent research progress on the molecular mechanism of yeast ethanol tolerance, as well as the genetic engineering manipulations to improve yeast ethanol tolerance. The studies reviewed here not only deepened our knowledge on yeast ethanol tolerance, but also provided basis for more efficient bioconversion for bio-energy production.
Subject(s)
Drug Tolerance , Genetics , Ethanol , Metabolism , Pharmacology , Fermentation , Genetic Engineering , Methods , Industrial Microbiology , Methods , Saccharomyces cerevisiae , Genetics , Saccharomyces cerevisiae Proteins , GeneticsABSTRACT
A unique one-step ethanol fermentation process was developed with the inulinase-producing strain Kluyveromyces marxianus YX01. Firstly, the impact of temperature on ethanol fermentation was investigated through flask fermentation, and the temperature of 35 degrees C was observed to be the optimum to coordinate inulinase production, inulin saccharification and ethanol fermentation. And then, the impact of aeration and substrate concentration was studied through batch fermentation in the 2.5 L fermentor, and the experimental data indicated that the average ethanol fermentation time was decreased at the aeration rates of 50 mL/min and 100 mL/min, but higher ethanol yield was obtained under non-aeration conditions with more substrate directed to ethanol production. The ethanol concentration of 92.2 g/L was achieved with the substrate containing 235 g/L inulin, and the ethanol yield was calculated to be 0.436, equivalent to 85.5% of its theoretical value. Finally, Jerusalem artichoke grown in salina and irrigated with seawater was fermented without sterilization treatment, 84.0 g/L ethanol was obtained with the substrate containing 280 g/L dry Jerusalem artichoke meal, and the ethanol yield was calculated to be 0.405, indicating the Jerusalem artichoke could be an alternative feedstock for grain-based fuel ethanol production.