To screen and identify a chitosanase with high stability, we cloned the chitosanase gene from Bacillus atrophaeus with a high protease yield from the barren saline-alkali soil and expressed this gene in Escherichia coli. The expressed chitosanase of B. atrophaeus (BA-CSN) was purified by nickel-affinity column chromatography. The properties including optimal temperature, optimal pH, substrate specificity, and kinetic parameters of BA-CSN were characterized. The results showed that BA-CSN had the molecular weight of 31.13 kDa, the optimal temperature of 55 ℃, the optimal pH 5.5, and good stability at temperatures below 45 ℃ and pH 4.0-9.0. BA-CSN also had good stability within 4 h of pH 3.0 and 10.0, be activated by K⁺, Na⁺, Mn²⁺, Ca²⁺, Mg²⁺, and Co²⁺, (especially by Mn²⁺), and be inhibited by Fe³⁺, Cu²⁺, and Ag⁺. BA-CSN showcased the highest relative activity in the hydrolysis of colloidal chitosan, and it had good hydrolysis ability for colloidal chitin. Under the optimal catalytic conditions, BA-CSN demonstrated the Michaelis constant K_m and maximum reaction rate V_max of 9.94 mg/mL and 26.624 μmoL/(mL·min), respectively, for colloidal chitosan. In short, BA-CSN has strong tolerance to acids and alkali, possessing broad industrial application prospects.
Bacillus/genetics* ; Hydrogen-Ion Concentration ; Escherichia coli/metabolism* ; Glycoside Hydrolases/biosynthesis* ; Substrate Specificity ; Enzyme Stability ; Chitosan/metabolism* ; Temperature ; Kinetics ; Cloning, Molecular ; Bacterial Proteins/biosynthesis* ; Recombinant Proteins/genetics*

Objective:To analyze the genetic evolution and molecular characteristics of H5N8 avian influenza viruses (AIVs) isolated from the poultry in a live poultry market (LPM) in Urumqi, Xinjiang.Methods:Oropharyngeal and cloacal swabs of poultry were collected from a LPM in Urumqi in 2016. AIVs were isolated by inoculating swab samples into chicken embryos. Hemagglutination test and RT-PCR were used to identify the AIVs. The genes of isolated AIVs were amplified with the universal primers of AIV and whole-genome sequencing was also performed. Pairwise sequence alignment and analysis of phylogenetic and molecular characteristics were performed using BLAST, Clustal W, MEGA-X and DNAStar software.Results:Five H5N8 AIVs were isolated from poultry. These strains shared a nucleotide identity of 99.70%-100.00%, which indicated that they were from the same source, and were named XJ-H5N8/2016. Phylogenetic analysis based on hemagglutinin( HA), NS and PB2 genes showed that these isolates were clustered together with H5N8 AIVs isolated from the migratory swans in Hubei, Shanxi and Sanmenxia, and the ducks in India during 2016 to 2017. Moreover, they were also clustered together with H5N6 AIVs isolated from minks in China and the first case of human infection in Fujian. The phylogenetic tree of neuraminidase( NA) gene indicated the five isolates clustered together with H5N8 AIVs isolated from ducks in India in 2016, and the phylogenetic trees of PB1, MP, PA and NP genes showed that they were clustered together with H5N8 AIVs isolated from wild birds and poultry in Egypt, Cameroon, Uganda, Congo and other African countries in 2017. The HA cleavage sites of XJ-H5N8/2016 contained five consecutive basic amino acids, indicating high pathogenicity. Multiple mutations in the genes of XJ-H5N8/2016 could enhance its virulence and pathogenicity to mammals. Conclusions:The five strains of H5N8 AIVs isolated from the LPM were highly pathogenic and closely related to the H5N8 AIVs isolated from migratory birds and poultry in Hubei, Shanxi, Sanmenxia area, Africa and India during 2016 to 2017. Meanwhile, some of the viral genes were also closely related to the H5N6 AIVs isolated from the minks and human in China. Multiple mutations could increase the virulence and pathogenicity of AIVs to mammals, which could pose a potential threat to public health.

Objective:To investigate the distribution and antimicrobial resistance profile of clinical bacteria isolated from blood culture in China.Methods:The clinical bacterial strains isolated from blood culture from member hospitals of Blood Bacterial Resistant Investigation Collaborative System (BRICS) were collected during January 2018 to December 2019. Antibiotic susceptibility tests were conducted with agar dilution or broth dilution methods recommended by US Clinical and Laboratory Standards Institute (CLSI). WHONET 5.6 was used to analyze data.Results:During the study period, 14 778 bacterial strains were collected from 50 hospitals, of which 4 117 (27.9%) were Gram-positive bacteria and 10 661(72.1%) were Gram-negative bacteria. The top 10 bacterial species were Escherichia coli (37.2%), Klebsiella pneumoniae (17.0%), Staphylococcus aureus (9.7%), coagulase-negative Staphylococci (8.7%), Pseudomonas aeruginosa (3.7%), Enterococcus faecium (3.4%), Acinetobacter baumannii(3.4%), Enterobacter cloacae (2.9%), Streptococci(2.8%) and Enterococcus faecalis (2.3%). The the prevalence of methicillin-resistant S. aureus (MRSA) and methicillin-resistant coagulase-negative Staphylococcus were 27.4% (394/1 438) and 70.4% (905/1 285), respectively. No glycopeptide-resistant Staphylococcus was detected. More than 95% of S. aureus were sensitive to amikacin, rifampicin and SMZco. The resistance rate of E. faecium to vancomycin was 0.4% (2/504), and no vancomycin-resistant E. faecalis was detected. The ESBLs-producing rates in no carbapenem-resistance E. coli, carbapenem sensitive K. pneumoniae and Proteus were 50.4% (2 731/5 415), 24.6% (493/2001) and 35.2% (31/88), respectively. The prevalence of carbapenem-resistance in E. coli and K. pneumoniae were 1.5% (85/5 500), 20.6% (518/2 519), respectively. 8.3% (27/325) of carbapenem-resistance K. pneumoniae was resistant to ceftazidime/avibactam combination. The resistance rates of A. baumannii to polymyxin and tigecycline were 2.8% (14/501) and 3.4% (17/501) respectively, and that of P. aeruginosa to carbapenem were 18.9% (103/546). Conclusions:The surveillance results from 2018 to 2019 showed that the main pathogens of bloodstream infection in China were gram-negative bacteria, while E. coli was the most common pathogen, and ESBLs-producing strains were in majority; the MRSA incidence is getting lower in China; carbapenem-resistant E. coli keeps at a low level, while carbapenem-resistant K. pneumoniae is on the rise obviously.

Objective:To analyze phylogenetic structure and molecular characteristics of H5N6 avian influenza virus (AIVs) isolated from live poultry market (LPM).Methods:Oropharyngeal and cloacal swabs from poultry, and environmental samples were collected from LPM in Urumqi in December 2018, AIVs were isolated and identified by inoculation of chicken embryo, hemagglutination test and RT-PCR, the viral whole genome was amplified with the universal primers of influenza A virus, and then sequenced, pairwise sequence alignments, phylogenetic and molecular characteristics analysis were performed by BLAST, Clustal W, MEGA-X and DNAStar software.Results:Six strains of H5N6 AIVs were isolated from poultry samples, the identity between the viral genes was high (99.4%-100.0%), so the isolates were the same source. BLAST analysis revealed that the viral NP sequence had the highest identity (99.7%) with H5N6 AIVs isolated from poultry in Suzhou, while the sequence of the remaining 7 viral genes had the highest identity (99.0%-100.0%) with H5N6 AIVs isolated from environment in Guangdong during 2017 to 2018. Phylogenetic analysis showed that the viral HA belonged to Clade 2.3.4.4C, and the viral HA, NA, PB1, PA, NP, and MP were all clustered together with H5N6 AIVs isolated from mink in Eastern China in 2018, while the PB2 and NS were clustered together with H5N6 AIVs isolated from environment in Guangdong from 2017 to 2018. The HA cleavage site contained multiple basic amino acid residues, which was highly pathogenic AIVs (HPAIVs). S137A and T160A mutations of HA could increase binding to human-type receptor SAα2, 6-Gal. Additionally, the viral multiple mutations, including 59-69 deletion in NA, the L89V, G309D, R477G, I495V, I504V, D391E, and A661E in PB2, as well as the P42S, D92E, and 80-84 deletion in NS1, could enhance the viral virulence and pathogenicity to mammals. Conclusions:The 6 strains of H5N6 HPAIVs isolated from LPM have relatively close genetic relationship with H5N6 AIVs isolated from mink in Eastern China and environment in Guangdong during 2017 to 2018, the viral multiple mutations could increase its pathogenicity to mammals, which could pose a potential risk to public health.

Background: The H5 avian influenza viruses (AIVs) of clade 2.3.4.4 circulate in wild and domestic birds worldwide. In 2017, nine strains of H5N6 AIVs were isolated from aquatic poultry in Xinjiang, Northwest China. Objectives: This study aimed to analyze the origin, reassortment, and mutations of the AIV isolates. Methods: AIVs were isolated from oropharyngeal and cloacal swabs of poultry. Identification was accomplished by inoculating isolates into embryonated chicken eggs and performing hemagglutination tests and reverse transcription polymerase chain reaction (RT-PCR). The viral genomes were amplified with RT-PCR and then sequenced. The sequence alignment, phylogenetic, and molecular characteristic analyses were performed by using bioinformatic software. Results: Nine isolates originated from the same ancestor. The viral HA gene belonged to clade 2.3.4.4B, while the NA gene had a close phylogenetic relationship with the 2.3.4.4C H5N6 highly pathogenic avian influenza viruses (HPAIVs) isolated from shoveler ducks in Ningxia in 2015. The NP gene was grouped into an independent subcluster within the 2.3.4.4B H5N8 AIVs, and the remaining six genes all had close phylogenetic relationships with the 2.3.4.4B H5N8 HPAIVs isolated from the wild birds in China, Egypt, Uganda, Cameroon, and India in 2016–2017, Multiple basic amino acid residues associated with HPAIVs were located adjacent to the cleavage site of the HA protein. The nine isolates comprised reassortant 2.3.4.4B HPAIVs originating from 2.3.4.4B H5N8 and 2.3.4.4C H5N6 viruses in wild birds. Conclusions These results suggest that the Northern Tianshan Mountain wetlands in Xinjiang may have a key role in AIVs disseminating from Central China to the Eurasian continent and East African.

Background: The H5 avian influenza viruses (AIVs) of clade 2.3.4.4 circulate in wild and domestic birds worldwide. In 2017, nine strains of H5N6 AIVs were isolated from aquatic poultry in Xinjiang, Northwest China. Objectives: This study aimed to analyze the origin, reassortment, and mutations of the AIV isolates. Methods: AIVs were isolated from oropharyngeal and cloacal swabs of poultry. Identification was accomplished by inoculating isolates into embryonated chicken eggs and performing hemagglutination tests and reverse transcription polymerase chain reaction (RT-PCR). The viral genomes were amplified with RT-PCR and then sequenced. The sequence alignment, phylogenetic, and molecular characteristic analyses were performed by using bioinformatic software. Results: Nine isolates originated from the same ancestor. The viral HA gene belonged to clade 2.3.4.4B, while the NA gene had a close phylogenetic relationship with the 2.3.4.4C H5N6 highly pathogenic avian influenza viruses (HPAIVs) isolated from shoveler ducks in Ningxia in 2015. The NP gene was grouped into an independent subcluster within the 2.3.4.4B H5N8 AIVs, and the remaining six genes all had close phylogenetic relationships with the 2.3.4.4B H5N8 HPAIVs isolated from the wild birds in China, Egypt, Uganda, Cameroon, and India in 2016–2017, Multiple basic amino acid residues associated with HPAIVs were located adjacent to the cleavage site of the HA protein. The nine isolates comprised reassortant 2.3.4.4B HPAIVs originating from 2.3.4.4B H5N8 and 2.3.4.4C H5N6 viruses in wild birds. Conclusions These results suggest that the Northern Tianshan Mountain wetlands in Xinjiang may have a key role in AIVs disseminating from Central China to the Eurasian continent and East African.

Objective:To analyze the EGFR mutation profile of lung cancer patients in Yunnan, and to provide evidence for clinical personalized treatment.Methods:Demographic and clinical data of 2 967 lung cancer patients undergoing EGFR identification were collected and analyzed from January 2014 to August 2019 in Yunnan Cancer Hospital.Results:The proportion of EGFR mutation in 2 967 patients with lung cancer was 46.2%. Univariate analysis showed that the proportion of EGFR mutation in women was higher than that in men ( P<0.001) and displayed a downward trend with age ( P=0.03). The mutation rate of ethnic minorities was higher than Han ( P=0.012). Mutation rate in patients without smoking history was higher than those with smoking history ( P<0.001), and patients without drinking history was higher than patients with drinking history ( P<0.001). Mutation rate in patients without family history of lung cancer was higher than those with family history ( P=0.008). The mutation rate of adenocarcinoma was higher than other pathological types ( P<0.001). The mutation rate was different among stages, and it was higher in early patients than that in advanced patients ( P<0.001). The mutation rate of tissue specimens was higher than those of cytology and peripheral blood samples ( P<0.001). The mutation rate of Xuanwei area was lower than that in non-Xuanwei area ( P<0.001). Multivariate analysis showed that gender ( P<0.001), age ( P=0.036), smoking history ( P<0.001), pathological type ( P<0.001), specimen type ( P<0.001), and whether or not Xuanwei area ( P<0.001) were the independent factors of EGFR mutation.The EGFR mutation was more common in female, non-smokers, adenocarcinoma, non-Xuanwei area, tissue specimen and young lung cancer patients.The mutation types of EGFR in 1 370 cases mainly included 19-Del and L858R. The predominant mutation of EGFR in Xuanwei area was L858R, while in non-Xuanwei area was 19-Del.The mutation rates of G719X, G719X+ L861Q, G719X+ S768I, and S768I in Xuanwei were higher while the mutation rates of 19-Del, L858R, and 20-ins were lower than non-Xuanwei area ( P<0.05). The 19-Del mutation rate of ethnic minorities is higher than that of Han ( P<0.001). The combined mutation rate of G719X, L861Q in Han was higher than that of ethnic minorities ( P=0.005). Conclusions:The EGFR mutation rate in lung cancer patients in Yunnan is similar to Asian and Chinese, and higher in female, non-smokers, adenocarcinomas, young and non-Xuanwei area patients. The most common types of EGFR mutation in Yunnan are 19-Del and L858R. The predominant mutation of EGFR in Xuanwei area is L858R, while in non-Xuanwei area is 19-Del. The mutation rates of G719X, G719X+ L861Q, G719X+ S768I and S768I are higher in Xuanwei patients than those in non-Xuanwei patients. The combined mutation rate of G719X and L861Q in Han nationality is higher than that of ethnic minorities.

Objective:To analyze the expressions of non-small-cell lung cancer (NSCLC) driver genes and their mutation distribution characteristics in the Yunnan-Kweichow plateau, and to provide evidences for personalized molecular targeted therapy of lung cancer in high-incidence areas.Methods:A retrospective analysis was performed on the medical records of patients with NSCLC who underwent combined lung cancer 8 gene detection, including epidermal growth factor receptor (EGFR), rat sarcoma viral oncogene (RAS), anaplastic lymphoma kinase (ALK), RET proto-oncogene (RET), v-Raf murine sarcoma viral oncogene homolog (BRAF), ROS proto-oncogene 1 (ROS1), human epidermal growth factor receptor-2 (HER-2), and cellular-mesenchymal to epithelial transition factor (MET), from January 2016 to August 2019 in Yunnan Cancer Hospital. Besides, we analyzed the expressions of NSCLC driver genes and their mutation distributions.Results:The positive rate of NSCLC driver genes in Yunnan was 67.05%(1 508/2 249). The mutation rates in Xishuangbanna (76.92%), Yuxi (72.38%), Xuanwei (71.88%), Qujing (71.24%), and Honghe (71.79%) were significantly higher than other areas. The mutation rates of Hui (84.38%), Hani (85.00%), Zhuang (75.00%), Buyi (100%), Manchu (100%), Tujia (100%) and Achang (100%) are significantly higher than the minority national average. Driver gene mutations were related to gender ( P<0.001), smoking history ( P<0.001), age ( P<0.001), pathological type ( P<0.001), and whether the Xuanwei area ( P=0.027), but not related to the nationality ( P=0.748) and family history of lung cancer ( P=0.676). The mutation rates of EGFR, RAS, BRAF, HER-2 and MET genes were 44.46%, 10.98%, 1.24%, 0.89% and 0.76%, and the rearrangement rates of ALK, RET and ROS1 genes were 4.67%, 1.29% and 0.89%, respectively.The mutation rate of EGFR in females was 56.67%, which was higher than 33.19% in males ( P<0.001). The mutation rate of RAS in males was 12.66%, which was higher than 9.17% in females ( P=0.010). The mutation rate of RAS in the Han was 11.49%, which was higher than 7.17% in the minority ( P=0.032). The rate of RAS mutation in Xuanwei patients was 24.74%, significantly higher than 8.15% in non-Xuanwei area ( P<0.001), and the EGFR mutation rate was 40.63%, which was lower than 45.25% in non-Xuanwei area ( P=0.045). The rate of ALK rearrangement in Xuanwei patients was 1.56%, which was significantly lower than 5.31% in the non-Xuanwei area ( P<0.001), and no HER-2 mutation patients were detected in Xuanwei area. The mutation rate of EGFR in patients with non-smoking history was 51.10%, significantly higher than 29.70% of patients with smoking history ( P<0.001). Meanwhile, the rate of ALK rearrangement with non-smoking history patients was 5.35%, which was also higher than 3.16% of patients with smoking history ( P<0.001). The rate of RAS mutation in patients with non-smoking history was 9.34%, lower than 14.63% of patients with smoking history ( P=0.008). Conclusions:The positive rate of driven gene expression in NSCLC patients from the Yunnan-Kweichow Plateau is slightly lower than the national average. The rates of EGFR and RAS mutations are similar to the domestic average. The rates of ROS1, ALK and RET genes rearrangements and the rates of BRAF, HER2 and MET gene mutations are slightly lower than the national average. EGFR, RAS and ALK genes in the NSCLC patients from Yunnan-Kweichow Plateau have high positive rates, and display different demographic and clinical characteristics, which are of great significance in the selection of targeted therapy populations.

Objective:To analyze the EGFR mutation profile of lung cancer patients in Yunnan, and to provide evidence for clinical personalized treatment.Methods:Demographic and clinical data of 2 967 lung cancer patients undergoing EGFR identification were collected and analyzed from January 2014 to August 2019 in Yunnan Cancer Hospital.Results:The proportion of EGFR mutation in 2 967 patients with lung cancer was 46.2%. Univariate analysis showed that the proportion of EGFR mutation in women was higher than that in men ( P<0.001) and displayed a downward trend with age ( P=0.03). The mutation rate of ethnic minorities was higher than Han ( P=0.012). Mutation rate in patients without smoking history was higher than those with smoking history ( P<0.001), and patients without drinking history was higher than patients with drinking history ( P<0.001). Mutation rate in patients without family history of lung cancer was higher than those with family history ( P=0.008). The mutation rate of adenocarcinoma was higher than other pathological types ( P<0.001). The mutation rate was different among stages, and it was higher in early patients than that in advanced patients ( P<0.001). The mutation rate of tissue specimens was higher than those of cytology and peripheral blood samples ( P<0.001). The mutation rate of Xuanwei area was lower than that in non-Xuanwei area ( P<0.001). Multivariate analysis showed that gender ( P<0.001), age ( P=0.036), smoking history ( P<0.001), pathological type ( P<0.001), specimen type ( P<0.001), and whether or not Xuanwei area ( P<0.001) were the independent factors of EGFR mutation.The EGFR mutation was more common in female, non-smokers, adenocarcinoma, non-Xuanwei area, tissue specimen and young lung cancer patients.The mutation types of EGFR in 1 370 cases mainly included 19-Del and L858R. The predominant mutation of EGFR in Xuanwei area was L858R, while in non-Xuanwei area was 19-Del.The mutation rates of G719X, G719X+ L861Q, G719X+ S768I, and S768I in Xuanwei were higher while the mutation rates of 19-Del, L858R, and 20-ins were lower than non-Xuanwei area ( P<0.05). The 19-Del mutation rate of ethnic minorities is higher than that of Han ( P<0.001). The combined mutation rate of G719X, L861Q in Han was higher than that of ethnic minorities ( P=0.005). Conclusions:The EGFR mutation rate in lung cancer patients in Yunnan is similar to Asian and Chinese, and higher in female, non-smokers, adenocarcinomas, young and non-Xuanwei area patients. The most common types of EGFR mutation in Yunnan are 19-Del and L858R. The predominant mutation of EGFR in Xuanwei area is L858R, while in non-Xuanwei area is 19-Del. The mutation rates of G719X, G719X+ L861Q, G719X+ S768I and S768I are higher in Xuanwei patients than those in non-Xuanwei patients. The combined mutation rate of G719X and L861Q in Han nationality is higher than that of ethnic minorities.

Objective:To analyze the expressions of non-small-cell lung cancer (NSCLC) driver genes and their mutation distribution characteristics in the Yunnan-Kweichow plateau, and to provide evidences for personalized molecular targeted therapy of lung cancer in high-incidence areas.Methods:A retrospective analysis was performed on the medical records of patients with NSCLC who underwent combined lung cancer 8 gene detection, including epidermal growth factor receptor (EGFR), rat sarcoma viral oncogene (RAS), anaplastic lymphoma kinase (ALK), RET proto-oncogene (RET), v-Raf murine sarcoma viral oncogene homolog (BRAF), ROS proto-oncogene 1 (ROS1), human epidermal growth factor receptor-2 (HER-2), and cellular-mesenchymal to epithelial transition factor (MET), from January 2016 to August 2019 in Yunnan Cancer Hospital. Besides, we analyzed the expressions of NSCLC driver genes and their mutation distributions.Results:The positive rate of NSCLC driver genes in Yunnan was 67.05%(1 508/2 249). The mutation rates in Xishuangbanna (76.92%), Yuxi (72.38%), Xuanwei (71.88%), Qujing (71.24%), and Honghe (71.79%) were significantly higher than other areas. The mutation rates of Hui (84.38%), Hani (85.00%), Zhuang (75.00%), Buyi (100%), Manchu (100%), Tujia (100%) and Achang (100%) are significantly higher than the minority national average. Driver gene mutations were related to gender ( P<0.001), smoking history ( P<0.001), age ( P<0.001), pathological type ( P<0.001), and whether the Xuanwei area ( P=0.027), but not related to the nationality ( P=0.748) and family history of lung cancer ( P=0.676). The mutation rates of EGFR, RAS, BRAF, HER-2 and MET genes were 44.46%, 10.98%, 1.24%, 0.89% and 0.76%, and the rearrangement rates of ALK, RET and ROS1 genes were 4.67%, 1.29% and 0.89%, respectively.The mutation rate of EGFR in females was 56.67%, which was higher than 33.19% in males ( P<0.001). The mutation rate of RAS in males was 12.66%, which was higher than 9.17% in females ( P=0.010). The mutation rate of RAS in the Han was 11.49%, which was higher than 7.17% in the minority ( P=0.032). The rate of RAS mutation in Xuanwei patients was 24.74%, significantly higher than 8.15% in non-Xuanwei area ( P<0.001), and the EGFR mutation rate was 40.63%, which was lower than 45.25% in non-Xuanwei area ( P=0.045). The rate of ALK rearrangement in Xuanwei patients was 1.56%, which was significantly lower than 5.31% in the non-Xuanwei area ( P<0.001), and no HER-2 mutation patients were detected in Xuanwei area. The mutation rate of EGFR in patients with non-smoking history was 51.10%, significantly higher than 29.70% of patients with smoking history ( P<0.001). Meanwhile, the rate of ALK rearrangement with non-smoking history patients was 5.35%, which was also higher than 3.16% of patients with smoking history ( P<0.001). The rate of RAS mutation in patients with non-smoking history was 9.34%, lower than 14.63% of patients with smoking history ( P=0.008). Conclusions:The positive rate of driven gene expression in NSCLC patients from the Yunnan-Kweichow Plateau is slightly lower than the national average. The rates of EGFR and RAS mutations are similar to the domestic average. The rates of ROS1, ALK and RET genes rearrangements and the rates of BRAF, HER2 and MET gene mutations are slightly lower than the national average. EGFR, RAS and ALK genes in the NSCLC patients from Yunnan-Kweichow Plateau have high positive rates, and display different demographic and clinical characteristics, which are of great significance in the selection of targeted therapy populations.