In December 2019, a new coronavirus was found in Wuhan, Hubei Province, China, and spread rapidly throughout the country, attracting global attention. On February 11, the World Health Organization (WHO) officially named the disease caused by 2019-nCoV coronavirus disease 2019 . With the increasing number of cases, health care workers (HCWs) from all over China volunteered to work in Hubei Province. Because of the strong infectivity of COVID-19, HCWs need to wear personal protective equipment (PPE), such as N95 masks, latex gloves, and protective clothing. Due to the long-term use of PPE, many adverse skin reactions may occur. Therefore, the purpose of this study is to explore the adverse skin reactions among HCWs using PPE.Questionnaires were used for the research; a quantitative study was carried out to determine the incidence of adverse skin reactions among HCWs using PPE.A total of 61 valid questionnaires were collected. The most common adverse skin reactions among HCWs wearing N95 masks were nasal bridge scarring (68.9%) and facial itching (27.9%). The most common adverse skin reactions among HCWs wearing latex gloves were dry skin (55.7%), itching (31.2%), and rash (23.0%). The most common adverse skin reactions among HCWs wearing protective clothing were dry skin (36.1%) and itching (34.4%).When most HCWs wear PPE for a long period of time, they will experience adverse skin reactions. The incidence of adverse skin reactions to the N95 mask was 95.1%, that to latex gloves was 88.5%, and that to protective clothing was 60.7%.

Background: Due to its high infectivity and concealment, the coronavirus disease 2019 (COVID-19) outbreak that occurred in Wuhan attracted global attention. A special nursing group of transdisciplinary nurses (TNs) who had not worked in respiratory medicine, infection departments, or emergency and intensive medicine but who accounted for a large proportion of all nurses also drew our attention. Few studies have examined this special group of TNs. Therefore, this study collected the experiences and views of TNs at the forefront of the COVID-19 outbreak to investigate their potential problems. Results: Twenty-five TNs and 19 nurses with experience in infectious diseases (non-TNs) were enrolled in the study. Compared with non-TNs, TNs showed higher levels of perceived stress and relatively less perceived social support. For TNs, the ambiguous roles, transition of operating mode, unfamiliar work content, and reversal of their daily schedule were the most common vocational problems. Additionally, most TNs had psychological problems such as anxiety, pain and insomnia. The incomprehension of parents, concern for family members and long-term isolation were the most common causes of psychological stress. Conclusion: This survey is the first to focus on the group of TNs at the forefront of the COVID-19 outbreak and to investigate their experiences, vocational issues and psychological stresses qualitatively and quantificationally. We found that TNs had more perceived stress and less perceived social support than non-TNs. The vocational and psychological issues of TNs should be highlighted. These findings identify important issues and offer insights into the underlying issues to help TNs ultimately win the battle against novel coronavirus epidemics. Methods: Semi-structured and face-to-face individual interviews and quantitative assessments were conducted. The Braun Clarke Thematic Analysis method and the strategy outlined by Miles and Huberman were used in the data analysis process of the qualitative study. The perceived stress scale and perceived social support scale were utilized to quantificationally evaluate the perceived stress level and the amount of perceived social support. Both qualitative and quantitative methods were adopted to assess the vocational and psychological perceptions and issues.

The budC gene coding for a new meso-2,3-butanediol dehydrogenase (BDH) from Serratia marcescens H30 was cloned and expressed in Escherichia coli BL21(DE3), purified, and characterized for its properties. The recombinant BDH with a molecular weight of 27.4 kDa exhibited a reversible transformation between acetoin and 2,3-butanediol. In the presence of NADH, BDH could catalyze the reduction of diacetyl and (3R)-acetoin to (3S)-acetoin and meso-2,3-butanediol, respectively, while (3S)-acetoin as a substrate could be further transformed into (2S, 3S)-2,3-butanediol at pH 9.0. For diol oxidation reactions, (3R)-acetoin and (3S)-acetoin were obtained when meso-2,3-butanediol and (2S,3S)-2,3-butanediol were used as the substrates with BDH and NAD(+). (2R,3R)-2,3-butanediol was not a substrate for the BDH at all. The low K m value (4.1 mM) in meso-2,3-butanediol oxidation reaction and no activity for diacetyl, acetoin, and 2,3-butanediol as the substrates with NADP(+)/NADPH suggested that the budC gene product belongs to a NAD(H)-dependent meso-2,3-BDH. Maximum activities for diacetyl and (3S/3R)-acetoin reduction were observed at pH 8.0 and pH 5.0 while for meso-2,3-butanediol oxidation it was pH 8.0. However, the optimum temperature for oxidation and reduction reactions was about 40 °C. In addition, the BDH activity for meso-2,3-butanediol oxidation was enhanced in the presence of Fe(2+) and for diacetyl and (3S/3R)-acetoin reduction in the presence of Mg(2+) and Mn(2+), while several metal ions inhibited its activity, particularly Fe(3+) for reduction of diacetyl and acetoin. Sequence analysis showed that the BDH from S. marcescens H30 possessed two conserved sequences including the coenzyme binding motif (GxxxGxG) and the active-site motif (YxxxK), which are present in the short-chain dehydrogenase/reductase superfamily.

Serratia sp. T241, a newly isolated xylose-utilizing strain, produced three 2,3-butanediol (2,3-BD) stereoisomers. In this study, three 2,3-butanediol dehydrogenases (BDH1-3) and one glycerol dehydrogenase (GDH) involved in 2,3-BD isomers formation by Serratia sp. T241 were identified. In vitro conversion showed BDH1 and BDH2 could catalyzed (3S)-acetoin and (3R)-acetoin into (2S,3S)-2,3-BD and meso-2,3-BD, while BDH3 and GDH exhibited the activities from (3S)-acetoin and (3R)-acetoin to meso-2,3-BD and (2R,3R)-2,3-BD. Four encoding genes were assembled into E. coli with budA (acetolactate decarboxylase) and budB (acetolactate synthase), responsible for converting pyruvate into acetoin. E. coli expressing budAB-bdh1/2 produced meso-2,3-BD and (2S,3S)-2,3-BD. Correspondingly, (2R,3R)-2,3-BD and meso-2,3-BD were obtained by E. coli expressing budAB-bdh3/gdh. These results suggested four enzymes might contribute to 2,3-BD isomers formation. Mutants of four genes were developed in Serratia sp. T241. Δbdh1 led to reduced concentration of meso-2,3-BD and (2S,3S)-2,3-BD by 97.7% and 87.9%. (2R,3R)-2,3-BD with a loss of 73.3% was produced by Δbdh3. Enzyme activity assays showed the decrease of 98.4% and 22.4% by Δbdh1 and Δbdh3 compared with the wild strain. It suggested BDH1 and BDH3 played important roles in 2,3-BD formation, BDH2 and GDH have small effects on 2,3-BD production by Serratia sp. T241.

BACKGROUND: Acetoin is a natural flavor commonly used in wine, buffer, honey, garnet berry and strawberry as a food additive. It also has been widely applied in cosmetics, pharmacy and chemical synthesis. Culture medium optimization and process control were carried out for efficient production of acetoin by a newly isoliated P. polymyxa CS107.RESULTS: An acetoin high producing strain, designated as CS107, was newly isolated and identified as P. polymyxa based on its physiological and biochemical characteristics as well as the 16S rDNA sequence. The medium composition was optimized in shake flask fermentations by a sequential statistical experimental design. Under the optimized conditions, acetoin concentration of 30.98 g L−1 was achieved with 71.83% of theoretical glucose conversion efficiency. Fed‐batch fermentation based on a suitable agitation speed was carried out in a 5 L jar, the maximum acetoin concentration of 55.3 g L−1 was obtained with the productivity of 1.32 g L−1 h−1 and the yield of 75.62%.CONCLUSION: A new strain for efficient production of acetoin, designated as P. polymyxa CS107, was obtained. The optimization of fermentation variables and fed‐batch culture resulted in a maximum acetoin concentration of 55.3 g L−1 in 5 L jar. Copyright © 2012 Society of Chemical Industry

The spread of coronavirus disease 2019 (COVID-19) around the world has put a heavy burden on human society and is also a great challenge facing medical staff. This study aimed to assess the difficulties faced by health care personnel (HCP) in using personal protective equipment (PPE) in clinical practice during the COVID-19 outbreak in Wuhan, China. One hundred twenty medical staff from the First Affiliated Hospital of Chongqing Medical University presented to the Wuhan First Hospital to provide medical assistance, from whom 20 HCP volunteered to participate in a focus group discussion attended by infection control nurse leaders. Participants’ responses and discussions were recorded, and the content was analyzed for themes. Observed difficulties included inappropriate PPE sizes, the design of the PPE and its complexity of use, doubts related to the quality and effectiveness of PPE, potential risks during doffing, space layout between clean and contaminated area, and poor comfort with PPE use. Other factors, such as the support environment, management, processes, preparedness, HCP, and equipment can also have a positive or negative impact on the use of PPE. Future efforts to optimize PPE use should focus on strengthening training for HCP using real items for increasing compliance with standardized protocols, improving PPE design, and performing further research on the risks, benefits, and best practices of PPE use.

Cordyceps militaris has commercially been cultivated, but its degenerated subcultures have gradually resulted in the reduced production. In this study, the biological characteristics and DNA change of degenerated strains of C. militaris were analyzed in detail. The results showed that the degenerated strains exhibited the lower growth rate, and the deficiency in fruit body formation and pigment production. The degradation of strains was not attributable to DNA changes identified by RAPD and SRAP. Compared to normal strains, the biochemical indexes of degradation strains and normal strains showed that the carotenoid content of degradation strains was significantly lower, the activities of cellulase and amylase of degradation strains were slight lower, and the EPS content was lower, but the IPS was higher. All these results suggested that the degradation of C. militaris may be caused by the inhibition or in harmony of metabolite synthesis involved in the metabolic regulation, which should be further verified.

BACKGROUND: Optically pure acetoin is an important potential pharmaceutical intermediate. It has also been widely used to synthesize novel optically active α-hydroxyketone derivatives and liquid crystal composites. Recombinant Escherichia coli was developed for efficient (3R)-acetoin production. Culture medium optimization and process control were carried out to improve (3R)-acetoin yield by the engineered strain. RESULTS: A synthetic pathway involved the budRAB genes from Serratia marcescens and NADH oxidase gene fromLactobacillus brevis in E. coli was developed for efficient (3R)-acetoin production. Batch culture showed that 23.4 g L −1 of (3R)-acetoin could be obtained from 60 g L −1 glucose by the engineered strain. Chiral-column GC analysis indicated that the stereoisomeric purity of (3R)-acetoin produced was 97.3%. Further, the medium composition was optimized in shake flasks by an orthogonal design method. Under optimal conditions, (3R)-acetoin concentration reached 38.3 g L −1 in flask fermentation. Fed-batch fermentation based on a suitable agitation speed was carried out in a 5 L bioreactor, and maximum (3R)-acetoin concentration of 60.3 g L −1 was achieved with a productivity of 1.55 g L −1 h −1 and yield 86.3%. CONCLUSION: An engineering E. coli for efficient (3R)-acetoin production was constructed. The optimization of fermentation variables and fed-batch culture resulted in a maximum (3R)-acetoin concentration of 60.3 g L −1 . DISCUSSIONChiral AC has recently been paid increasing attention due to its potential industrial and pharmaceutical applications. 7 However, natural microorganisms usually produce a mixture of (3R)-AC and (3S)-AC, which is difficult to accumulate due to a large J Chem Technol Biotechnol 2015; 90: 93-100