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Corynebacterium glutamicum, an important microorganism to produce amino acids and organic acids, has been widely applied in food and medicine fields. Therefore, using editing tools to study the function of unknown genes in C. glutamicum has great significance for systematic development of industrial strain with efficient and novel production capability. Recently, gene editing has been greatly developed. Traditional gene editing based on homologous recombination and gene editing mediated by nuclease are successfully applied in C. glutamicum. Among these, the CRISPR system has been developed to be a main tool used for gene knockout of C. glutamicum due to its advantages of efficiency, simplicity and good target specificity. However, more efficient and reliable knockout system is still urgently demanded, to help develop high-performing strains in industrial application.
Subject(s)
CRISPR-Cas Systems , Clustered Regularly Interspaced Short Palindromic Repeats , Corynebacterium glutamicum , Genetics , Gene Editing , Glutamic Acid , Industrial MicrobiologyABSTRACT
Hydroxy amino acids, constituents of chiral pharmaceutical intermediates or precursors, have a variety of unique functions in the research fields of biotechnology and molecular biology, i.e. antifungal, antibacterial, antiviral and anticancer properties. Biosynthesis of hydroxy amino acids is preferred because of its high specificity and selectivity. The hydroxylation of hydrophobic amino acids is catalyzed by hydroxylase, which belongs to the mononuclear non-heme Fe(Ⅱ)/α-ketoglutarate-dependent dioxygenases (Fe/αKGDs). Fe/αKGDs utilize an (Fe(Ⅳ)=O) intermediate to activate diverse oxidative transformations with key biological roles in the process of catalytic reaction. Here, we review the physiological properties and synthesis of hydroxy amino acids, especially for the 4-HIL and hydroxyproline. The catalytic mechanism of Fe/αKGDs is elucidated, and the applications of hydroxy amino acids in industrial engineering are also discussed.
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Objective To assess the application of intracavitary electrocardiography (IC-ECG) during the insertion of the Groshong peripherally inserted central catheters (PICC).Methods A total of 168 patients (aged 20-76 years) with gynecologic tumors who required the insertion of Groshong PICC because of various clinical conditions between January 2013 and December 2014 were selected into this study in Zhongnan Hospital of Wuhan University.During PICC insertion, the P-wave of IC-ECG helped general judgments about the position and direction of the tip of catheters, hence guiding the intubation.Precise position was determined by Xray following the fastening of catheters, based on which the accuracy and sensitivity of IC-ECG in the insertion of Groshong PICC were evaluated.Results All the cases presented typical changes of P-wave.However, 15 cases exhibited no such alternations in the first placement however deep or shallow the catheters were, in whom the typical P-wave was induced after withdrawal and replacement of the catheters with adjustment of patient position.According to the X-ray (gold standard), the accuracy and sensitivity of IC-ECG in diagnosing position of tip in the superior vena cava (SVC) were 98.8％ and 98.8％, respectively.The accuracy of diagnosing the position at the optimum location in the SVC reached 97.0％.Conclusions A high peaked P-wave of similar shape could be observed in IC-ECG in the insertion of Groshong PICC.IC-ECG could remarkably increase the positioning accuracy of PICC tip into the SVC;meanwhile, the optimal inserted length of the catheters could be determined by monitoring the changes of the P-wave with IC-ECG during insertion.
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Objective To analyze the changes of P wave of intracavitary electrocardiogram (ECC) in the placement of periph erally inserted central venous catheters (PICC), and to explore whether the intracavitary ECG can be used to guide the procedure. Methods PICC was inserted in 62 adult patients under intracavitary ECC-guided technique. The intracavitary ECC were recorded in different parts of vessel access through micro-guidewire. Results The intracavitary ECG extracted through micro-guidewire were accurately recorded in all patients. The amplitudes of P wave were (1.11 ±0.36)mm, (1.12±0.28)mm,(1.56±0.45)mm, (4.03±1.87)mm, (5.90±2.45)mm, (7.90±2.95)mm, (9.87±2.77)mm, (5.00±1.76)mm, (2.50±1.73)mm when PICC tip was located in the axillary, subclavian and brachiocephalic vein, in the superior, middle and inferior SVC, at the SVC-right atrium junction, and in the middle, inferior right atrium,respectively. The amplitude of P wave was 1.14±0.34mm in 10 patients with PICC tip malposition in the internal jugular vein. Conclusions The intracavitary ECG can be extracted with the microguidewire of PICC system. The amplitude of P wave is related to the location of PICC tip, which can be used to guide the PICC insertion and positioning.
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Objective To discuss the curative effect of unremitting pump infusion of microdose urokinase(100 000 u/24 h)into the cerebral venous sinus in treating thrombosis in cerebral venous sinus which had anatomical variation. Methods Mechanical disruption of the thrombus and unremitting pump infusion of microdose urokinase(100 000 u/24 h)into the cerebral venous sinus for 48-96 hours were employed in 9 patients with thrombosis in anatomically varied cerebral venous sinus.After the procedure the original disorder was actively treated and the anticoagulant therapy was continued for 6 months.A follow-up of 6-12 months(mean 10 months) was conducted. Results Recanalization of the previously occluded cerebral venous sinus was obtained in all 9 patients.The dose of urokinase was 100 000 u/24 h in 8 patients.For the remaining one patient the dose of urokinase was 100 000 u/24 h in the first 48 hours,then the dose Was increased to 250 000u/24 h. Excellent result was obtained in all patients.Conclusion Unremitting pump infusion of microdose urokinase into the cerebral venous sinus can effectively treat the thrombosis in anatomically varied cerebral venous sinus.
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The therapeutic effectiveness of nutritional support in the treatment of severe chronic hepatitis and posthepatitic cirrhosis was evaluated. 143 patients with severe chronic hepatitis and 83 with posthepatitic cirrhosis were evaluated with SGA for assessing the nutritional status before the treatment. Patients with severe chronic hepatitis were divided into three groups: group A subject to enteral nutrition (EN) and parenteral nutrition (PN), group B subject to comprehensive treatment (CT)+PN; group C subject to CT+EN. The patients with posthepatitic cirrhosis were divided into two groups: group D receiving CT and group E receiving CT+PN+EN. The function of liver and kidney and nutritional status were monitored to assess the therapy in 6 weeks. The results showed before treatment, over 90 % patients had moderate to severe malnutrition. After nutritional support, the liver function (ALT, T-bil) and nutritional status (TP, TC) in group A was improved significantly as compared with that in groups B and C (P<0.05). Compared with group D, the values of TP and Alb were increased significantly in group E (P<0.05), but the levels of ALT, AST and T-bil had no obvious change. It was suggested that most patients with severe chronic hepatitis or posthepatitic cirrhosis had malnutrition to varying degrees. The nutritional support treatment could obviously improve the nutritional status of these patients, and was helpful to ameliorate the liver function of the patients with severe chronic hepatitis. Among the methods of nutritional support treatment, PN combined with EN had the best effectiveness.
ABSTRACT
The therapeutic effectiveness of nutritional support in the treatment of severe chronic hepatitis and posthepatitic cirrhosis was evaluated. 143 patients with severe chronic hepatitis and 83 with posthepatitic cirrhosis were evaluated with SGA for assessing the nutritional status before the treatment. Patients with severe chronic hepatitis were divided into three groups: group A subject to enteral nutrition (EN) and parenteral nutrition (PN), group B subject to comprehensive treatment (CT) +PN; group C subject to CT+ EN. The patients with posthepatitic cirrhosis were divided into two groups: group D receiving CT and group E receiving CT+PN+EN. The function of liver and kidney and nutritional status were monitored to assess the therapy in 6 weeks. The results showed before treatment, over 90 % patients had moderate to severe malnutrition. After nutritional support, the liver function (ALT, T-biil) and nutritional status (TP, TC) in group A was improved significantly as compared with that in groups B and C (P＜0.05). Compared with group D,the values of TP and Alb were increased significantly in group E (P＜0.05), but the levels of ALT, AST and T-bil had no obvious change. It was suggested that most patients with severe chronic hepatitis or posthepatitic cirrhosis had malnutrition to varying degrees. The nutritional support treatment could obviously improve the nutritional status of these patients, and was helpful to ameliorate the liver function of the patients with severe chronic hepatitis. Among the methods of nutritional support treatment, PN combined with EN had the best effectiveness.