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Synthetic and Systems Biotechnology 2023年第2期8卷 227-234页

作者： Yuqi Wang Ning Li Xiaoyu Shan Xinrui Zhao Yang Sun Jingwen Zhou Key Laboratory of Straw Comprehensive Utilization and Black Soil Conservation Ministry of EducationCollege of Life SciencesJilin Agricultural UniversityChangchun130118China Key Laboratory of Industrial Biotechnology Ministry of Education and School of BiotechnologyJiangnan University1800 Lihu RoadWuxiJiangsu214122China Science Center for Future Foods Jiangnan University1800 Lihu RoadWuxiJiangsu214122China Jiangsu Provisional Research Center for Bioactive Product Processing Technology Jiangnan University1800 Lihu RoadWuxiJiangsu214122China

Phycocyanobilin(PCB)is widely used in healthcare,food processing,and *** coli is the common engineered bacterium used to produce ***,it still suffers from low production level,pre-cursor deficiency,and low catalytic *** this study,a highly efficient PCB-producing strain was ***,chassis strains and enzyme sources were screened,and copy numbers were optimized,affording a PCB titer of 9.1 mg/*** importantly,the rate-limiting steps of the PCB biosynthetic pathway were determined,and the supply of precursors necessary for PCB synthesis was increased from endogenous sources,affording a titer of 21.4 mg/***,the key enzymes for PCB synthesis,HO1 and PcyA,were assembled into a multi-enzyme complex using the short peptide tag RIAD-RIDD,and 23.5 mg/L of PCB was ***,the basic con-ditions for PCB fermentation were initially determined in 250 mL shake flasks and a 5-L bioreactor to obtain higher titers of *** final titer of PCB reached 147.0 mg/L,which is the highest reported titer of PCB so *** research provided the foundation for the industrial production of PCB and its derivatives.

关键词： Phycocyanobilin Heme Metabolic engineering escherichia coli

Wetting patterns and bacterial distributions in different soils from a surface point source applying effluents with varying escherichia coli concentrations

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Journal of Integrative Agriculture 2016年第7期15卷 1625-1637页

作者： WEN Jie LI Jiu-sheng LI Yan-feng State Key Laboratory of Simulation and Regulation of Water Cycle in River Basin China Institute of Water Resources andHydropower ResearchBeijing 100048P.R.China

Understanding bacterial transportation in unsaturated soil is helpful for reducing and avoiding pathogenic contamination that may be induced by irrigation with reclaimed waste water and for developing better irrigation management practic-es. Experiments were conducted to study the transport of a typical bacterium,escherichia coli （E. coli）, in a sandy and a sandy loam soil under different application rates and input concentrations. A 30° wedge-shaped plexiglass container was used to represent one twelfth of the complete cylinder in the experiments. The apparent cylindrical application rate varied from 1.05 to 5.76 L h–1 and the input concentration ofE. coli from magnitude of 102 to 107 colony-forming unit （CFU） mL–1. For a given volume of water applied, an increase in application rate resulted in an increase in the wetted radius and a decrease in the wetted depth. In the sandy loam soil, the water spread out in a circular-arc shaped saturated zone on the surface, and the ultimate saturated entry radius increased with the application rate. An increasing application rate of water suspended bacteria alowed a more rapid transport of bacteria, thus acceleratingE. coli transport rate and resulting in a larger distributed volume ofE. coli for both soil types. For the sandy soil, more than 70% of theE. coli that was de-tected within the entire wetted volume concentrated in the range of 10 cm from the point source, and the concentration of E. colidecreased greatly as the distance from the point source increased. More than 98% of theE. coli was detected in a range of 5 cm around the saturated wetted zone for the sandy loam soil. For both soil types tested, an extremely high concentration ofE. coli was observed in the proximity of the point source, and the peak value increased with an increased input concentration. In principle, using an emitter with relative lower application rate would be effective to restrictE. coli transport. To reduce bacterial concentration in the sewage

关键词： application rate drip irrigation escherichia coli input concentration

Dietary inclusion of multispecies probiotics to reduce the severity of post-weaning diarrhea caused by escherichia coli F18+ in pigs

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Animal Nutrition 2021年第2期7卷 326-333页

作者： Yawang Sun Marcos E.Duarte Sung Woo Kim Department of Animal Science North Carolina State UniversityRaleighNC27695United States

This study was aimed to determine the efficacy of multispecies probiotics in reducing the severity of post-weaning diarrhea caused by enterotoxigenic escherichia coli(ETEC)F18+on newly weaned ***-two pigs(16 barrows and 16 gilts,BW=6.99±0.33 kg)at 21 d of age were individually allotted in a randomized complete block design with 2×2 factorial arrangement of *** were selected from sows not infected previously and not vaccinated against *** were fed experimental diets for 25 d based on 10 d phase 1 and 15 d phase *** factors were ETEC challenge(oral inoculation of saline solution or *** F18+at 2×109 CFU)and probiotics(none or multispecies probiotics 0.15%and 0.10%for phase 1 and 2,respectively).Body weight and feed intake were measured on d 5,9,13,19,and *** scores were measured *** samples were taken on d 19 and *** d 25,all pigs were euthanized to obtain samples of digesta,intestinal tissues,and *** tumor necrosis factor alpha(TNFα),malondialdehyde(MDA),peptide YY(PYY),and neuropeptide Y(NPY)were measured in serum and intestinal *** were analyzed using the MIXED procedure of *** fecal score of pigs was increased(P<0.05)by ETEC challenge at the post-challenge *** ETEC challenge decreased(P<0.05)jejunal villus height and crypt depth,tended to increase(P=0.056)jejunal TNFα,increased(P<0.05)ileal crypt depth,and decreased(P<0.05)serum *** probiotics decreased(P<0.05)serum TNFα,tended to reduce(P=0.064)jejunal MDA,tended to increase(P=0.092)serum PYY,and increased(P<0.05)jejunal villus height,and especially villus height-to-crypt depth ratio in challenged *** performance of pigs were not affected by ETEC challenge,whereas the probiotics increased(P<0.05)ADG and ADFI and tended to increase(P-0.069)G:F *** conclusion,ETEC F18+challenge caused diarrhea,intestinal inflammation and morphological damages without affecting the growth *** multispecies probiotics enhanced growth pe

关键词： escherichia coli Growth performance Gut health Nursery pig Post-weaning diarrhea Probiotic

Prevalence and characteristics of extended spectrum β-lactamase-producing escherichia coli from bovine mastitis cases in China

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Journal of Integrative Agriculture 2018年第6期17卷 1246-1251页

作者： YANG Feng ZHANG Shi-dong SHANG Xiao-fei WANG Xu-rong WANG Ling YAN Zuo-ting LI Hong-sheng Lanzhou Institute of Husbandry and Pharmaceutical Sciences Chinese Academy of Agricultural Sciences

The aim of the study was to investigate the prevalence and characterization of extended-spectrum β-lactamase （ESBL）- producing escherichia coli isolated from bovine mastitis cases in China. ChromID ESBL agar was used to confirm ESBL-producing E. coli. PCR and DNA sequencing were employed to characterize the genotype of ESBL-producers. Antimicrobial susceptibility was measured by disc diffusion. Overall, 73 of 318 E. coli isolates （22.96％） were identified as ESBL-producers. Of these ESBL-producing E. coli, the prevalence of blaCTX-M and blaTEM-1 was 97.26 and 71.23％, respectively. The predominant CTX-M-type ESBL was CTX-M-15 （65.75％）, followed by CTX-M-14 （10.96％）, CTX-M-55 （9.59％）, CTX-M-64 （5.48％）, CTX-M-65 （4.11％） and CTX-M-3 （1.37％）. This study is the first report of CTX-M-64 and CTX-M-65 in E. coli isolated from bovine mastitis. Furthermore, 72 ESBL-producing E. coli isolates （98.63％） were found to be multidrug-resistance. This study noted high prevalence and rates of antimicrobial resistance of ESBL-producing E. coli isolates from bovine mastitis cases in China.

关键词： extended spectrum β-lactamase escherichia coli multidrug-resistance bovine mastitis

Effect of ultraviolet irradiation and chlorination on ampicillin-resistant escherichia coli and its ampicillin resistance gene

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Frontiers of Environmental Science & Engineering 2016年第3期10卷 522-530页

作者： Yuchen PANG Jingjing HUANG Jinying XI Hongying HU Yun ZHU Environmental Simulation and Pollution Control State Key Joint Laboratory School of Environment Tsinghua University Beijing 100084 China State Environmental Protection Key Laboratory of Microorganism Application and Risk Control (SMARC) Graduate School at Shenzhen Tsinghua University Shenzhen 518055 China China Power Engineering Consulting Group Corporation Beijing 100120 China Institute of Biophysics Chinese Academy of Sciences Beijing 100101 China School of Life Sciences Tsinghua University Beijing 100084 China

Antibiotic resistance is a serious public health risk that may spread via potable and reclaimed water. Effective disinfection is important for inactivation of antibiotic-resistant bacteria and disruption of antibiotic resistance genes. Ampicillin is a widely prescribed antibiotic but its effectiveness is increasingly undermined by resistance. In this study, changes in ampicillin resistance for escherichia coli （E. coli） CGMCC 1.1595 were analyzed after exposure to different doses of ultraviolet （UV） or chlorine, and damage incurred by the plasmid encoding ampicillin resistance gene blaTEM-1 was assessed. We reported a greater stability in ampicillinresistant E. coli CGMCC 1.1595 after UV irradiation or chlorination when compared with previously published data for other E. coli strains. UV irradiation and chlorination led to a shift in the mortality frequency distributions of ampicillin-resistant E. coli when subse-quently exposed to ampicillin. The ampicillin hemiinhibitory concentration （IC5o） without disinfection was 3800mg·L^-1, and an increment was observed after UV irradiation or chlorination. The IC50 of ampicillin-resistant E. coli was 1.5-fold higher at a UV dose of 40 mJ·cm^-2, and was 1.4-fold higher when exposed to 2.0 mg·L^-1 chlorine. These results indicate that UV irradiation and chlorination can potentially increase the risk of selection for E. coli strains with high ampicillin resistance. There was no evident damage to blaTEM-1 after 1-10 mg Cl2· L^-1 chlorination, while a UV dose of 80 mJ·cm^-2 yielded a damage ratio for blaTEM-1 of approximately ***, high UV doses are required for effective disruption of antibiotic resistance genes in bacteria.

关键词： antibiotic resistance escherichia coli ampicillin resistance gene ultraviolet irradiation chlorination

Engineering escherichia coli for high-yield production of ectoine

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Green Chemical Engineering 2023年第2期4卷 217-223页

作者： Daoan Wang Jiamin Chen Yang Wang Guocheng Du Zhen Kang The Science Center for Future Foods Jiangnan UniversityWuxi214122China The Key Laboratory of Carbohydrate Chemistry and Biotechnology Ministry of EducationJiangnan UniversityWuxi214122China The Key Laboratory of Industrial Biotechnology Ministry of EducationSchool of BiotechnologyJiangnan UniversityWuxi214122China

Ectoine is a natural macromolecule protector and synthesized by some *** provides protections against radiation-mediated oxidative damages and is widely used as a bioactive ingredient in pharmaceutics and *** meet its growing commercial demands,we engineered escherichia coli strains for the high-yield production of *** ectABC gene cluster from the native ectoine producer Halomonas elongata was intro-duced into different escherichia coli(***)strains via plasmids and 0.8 g L^(-1)of ectoine was produced in flask cultures by engineered *** BL21(DE3).Subsequently,we designed the ribosome-binding sites of the gene cluster to fine-tune the expressions of genes ectA,ectB,and ectC,which increased the ectoine yield to 1.6 g L^(-1).After further combinatorial overexpression of Corynebacterium glutamicum aspartate kinase mutant(G1A,C932T)and the *** aspartate-semialdehyde dehydrogenase to increase the supply of the precursor,the titer of ectoine reached to 5.5 g L^(-1)in flask ***,the engineered strain produced 60.7 g L^(-1)ectoine in fed-batch cultures with a conversion rate of 0.25 g/g glucose.

关键词： Ectoine escherichia coli Metabolic engineering RBS design

Transmission of Carbapenem Resistance Between Human and Animal NDM-Positive escherichia coli Strains

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Engineering 2022年第8期8卷 24-33页

作者： Yingbo Shen Fupin Hu Yongqiang Wang Dandan Yin Lu Yang Yiqiang Chen Chunyan Xu Jiyun Li Junyao Jiang Xueyang Wang Yulin Fu Dongyan Shao Dejun Liu Tengfei Ma Chang Cai Zhangqi Shen Shaolin Wang Juan Li Rong Zhang Yuebin Ke Congming Wu Jianzhong Shen Timothy R.Walsh Yang Wang Beijing Key Laboratory of Detection Technology for Animal-Derived Food Safety College of Veterinary MedicineChina Agricultural UniversityBeijing 100193China CAS Key Laboratory of Pathogenic Microbiology and Immunology Institute of MicrobiologyChinese Academy of SciencesBeijing 100101China Institute of Antibiotics&Key Laboratory of Clinical Pharmacology of Antibiotics(MoH) Huashan HospitalFudan UniversityShanghai 200040China Department of Preventive Veterinary Medicine College of Veterinary MedicineChina Agricultural UniversityBeijing 100193China State Key Laboratory of Animal Nutrition College of Animal Science and TechnologyChina Agricultural UniversityBeijing 100193China College of Animal Science and Technology College of Veterinary MedicineZhejiang A and F UniversityHangzhou 311300China State Key Laboratory for Infectious Disease Prevention and Control Collaborative Innovation Center for Diagnosis and Treatment of Infectious DiseaseNational Institute for Communicable Disease Control and PreventionChinese Center for Disease Control and Prevention(CDC)Beijing 102206China The Second Affiliated Hospital of Zhejiang University Zhejiang UniversityHangzhou 310009China Key Laboratory of Genetics&Molecular Medicine of Shenzhen Shenzhen Center for Disease Control and PreventionShenzhen 518055China Department of Zoology University of OxfordOxford OX13SZUK

Although carbapenem use is prohibited in animals in China,carbapenem-resistant escherichia coli(CREC),especially New Delhi metallo-β-lactamase(NDM)-producing strains,are widely prevalent in foodproducing *** present,the impact of livestock-associated CREC strains on human populations at the national level is ***,we conduct a retrospective cross-sectional study to investigate the prevalence of CREC from clinical settings across 22 Chinese provinces or municipalities and analyze anthropogenic factors associated with their *** also ascertain the blaNDMand blaKPCabundance among pig and chicken farms and present a detailed genomic framework for CREC of animal and human ***,631/29799(2.1%)clinical escherichia coli(***)isolates were identified as *** analysis revealed that being male,an age below 1,an age between 13 and 18,provinces with greater chicken production,and provinces with higher pig production were associated with higher odds of CREC *** general,73.8%(n=45/61)of pig farms and 62.2%(n=28/45)of chicken farms had a blaNDMabundance of 1×10^(-5)to 1×10^(-3)and 1×10^(-3)to 1×10^(-2),*** all the Chinese NDM-positive ***(n=463)available at the National Center for Biotechnology Information(NCBI),the genomic analysis revealed that blaNDM-5and Inc X3 were the predominant carbapenemase gene-plasmid combination,while a highly homogeneous relationship between NDM-positive isolates from humans and animals was demonstrated at the plasmid and core genome *** the findings suggest frequent CREC transmission between humans and animals,indicating that further discussions on the use of antibiotics in animals and humans are needed,both in China and across the globe.

关键词： Carbapenem resistance escherichia coli blaNDM-5 One Health Antimicrobial resistance transmission

Biotransformation of ethylene glycol by engineered escherichia coli

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Synthetic and Systems Biotechnology 2024年第3期9卷 531-539页

作者： Wenlong Yan Xinhua Qi Zhibei Cao Mingdong Yao Mingzhu Ding Yingjin Yuan Frontiers Science Center for Synthetic Biology and Key Laboratory of Systems Bioengineering(Ministry of Education) School of Chemical Engineering and TechnologyTianjin UniversityTianjin300072China Frontiers Research Institute for Synthetic Biology Tianjin UniversityTianjin300072China

There has been extensive research on the biological recycling of PET waste to address the issue of plastic waste pollution,with ethylene glycol(EG)being one of the main components recovered from this ***,finding ways to convert PET monomer EG into high-value products is crucial for effective PET waste *** this study,we successfully engineered escherichia coli to utilize EG and produce glycolic acid(GA),expecting to facilitate the biological recycling of PET *** engineered ***,able to utilize 10 g/L EG to produce 1.38 g/L GA within 96 h,was initially ***,strategies based on overexpression of key enzymes and knock-out of the competing pathways are employed to enhance EG utilization along with GA *** engineered ***,characterized by the highest GA production titer and substrate conversion rate,was *** GA titer increased to 5.1 g/L with a yield of 0.75 g/g EG,which is the highest level in the shake flake *** level analysis and metabolomic analysis were then conducted,revealing that overexpression of key enzymes and knock-out of the competing pathways improved the metabolic flow in the EG *** improved metabolic flow also leads to accelerated synthesis and metabolism of amino acids.

关键词： PET biological recycling Ethylene glycol utilization Glycolic acid production escherichia coli Synthetic biology Metabolomics analysis

Phytogenic feed additives alleviate pathogenic escherichia coli-induced intestinal damage through improving barrier integrity and inhibiting inflammation in weaned pigs

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Journal of Animal Science and Biotechnology 2023年第1期14卷 295-306页

作者： Se Yeon Chang Min Ho Song Ji Hwan Lee Han Jin Oh Yong Ju Kim Jae Woo An Young Bin Go Dong Cheol Song Hyun AhCho Seung Yeol Cho Dong Jun Kim Mi Suk Kim Hyeun Bum Kim Jin Ho Cho Department of Animal Science Chungbuk National UniversityCheongju 28644South Korea. Division of Animal and Dairy Science Chungnam National UniversityDaejeon 34134South Korea. Eugene-Bio Suwon 16675South Korea. Department of Animal Resources Science Dankook UniversityCheonan 31116South Korea.

Background:This study was conducted to investigate the effects of each phytogenic feed additive(PFA;PFA1,bitter citrus extract;PFA2,a microencapsulated blend of thymol and carvacrol;PFA3,a mixture of bitter citrus extract,thymol,and carvacrol;PFA4,a premixture of grape seed,grape marc extract,green tea,and hops;PFA5,fenugreek seed powder)on the growth performance,nutrient digestibility,intestinal morphology,and immune response in weaned pigs infected with escherichia coli(***).Results:A total of 634-week-old weaned pigs were placed in individual metabolic cages and assigned to seven treatment *** seven treatments were as follows:1)NC;basal diet without *** challenge,2)PC;basal diet with *** challenge,3)T1;PC+0.04%PFA1,4)T2;PC+0.01%PFA2,5)T3;PC+0.10%PFA3,6)T4;PC+0.04%PFA4,7)T5;PC+0.10%*** experiments lasted in 21 d,including 7 d before and 14 d after the first *** *** the *** challenge treatments,all pigs were orally inoculated by dividing a total of 10 mL of *** F18 for 3 consecutive *** PFA-added groups significantly increased(P<0.05)average daily gain and feed efficiency and decreased(P<0.05)the fecal score at d 0 to 14 post-inoculation(PI).Tumor necrosis factorαwas significantly lower(P<0.05)in the PFA-added groups except for T1 in d 14 PI compared to the PC *** T3 had a higher(P<0.05)immunoglobulin G and immunoglobulin A concentration compared to the PC treatment at d 7 ***,T3 showed significantly higher(P<0.05)villus height:crypt depth and claudin 1 expression in ileal mucosa,and significantly downregulated(P<0.05)the expression of calprotectin compared to the PC ***:Supplementation of PFA in weaned pigs challenged with *** alleviated the negative effects of *** and improved growth *** them,the mixed additive of bitter citrus extract,thymol,and carvacrol showed the most effective results,improving immune response,intestinal morphology,and expression of tight junction

关键词： Barrier integrity escherichia coli Immunity Phytogenic feed additive Post-weaning diarrhea Weaned pigs

Cloning of a novel phytase from an anaerobic rumen bacterium, Mitsuokella jalaludinii, and its expression in escherichia coli

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Journal of Integrative Agriculture 2015年第9期14卷 1816-1826页

作者： TAN Wan-qin Phang Chiun Yee Sieo Chin Chin Yiap Beow Chin Clemente Michael Wong Vui Ling Norhani Abdullah Son Radu Ho Yin Wan Laboratory of Vaccines and Immunotherapeutics Institute of BioscienceUniversiti Putra Malaysia Department of Microbiology Faculty of Biotechnology and Biomolecular SciencesUniversiti Putra Malaysia Department of Life Sciences School of Pharmacy and HealthFaculty of Medicine and HealthInternational Medical University Biotechnology Research Institute Universiti Malaysia Sabah Institute of Tropical Agriculture Universiti Putra Malaysia Department of Biochemistry Faculty of Biotechnology and Biomolecular SciencesUniversiti Putra Malaysia Department of Food Science Faculty of Food Science and TechnologyUniversiti Putra Malaysia

The ful length phytase gene of Mitsuokel a jalaludini was successful y cloned and was found to be 1 047 bp in length, with 348 amino acids, and was designated as PHY7 phytase gene. A comparison of the sequence of PHY7 phytase gene of M. jalaludini with various microbial phytase gene sequences showed that it was not similar to those from other bacteria except Selenomonas ruminatium, thus suggesting that they may both express a new class of phytase. The PHY7 phytase gene was subsequently subcloned into bacterial expression vector, pET32a, for expression in escherichia coli strain Ro-setta-gami. Expression of the recombinant phytase gene was optimised and characterised. The recombinant phytase was estimated to be approximately 55 kDa by SDS-PAGE analysis. The recombinant phytase exhibited optimum activity at 55°C, pH 4.5 and showed good pH stability from pH 3.5 to 5.5 (>78%relative activity). Metal ions such as Ca2+, Mg2+, and K+were found to exert signiifcant stimulatory effect on the recombinant phytase activity while Cu2+, Fe3+, and Zn2+greatly inhibited the enzyme activity. The recombinant phytase showed moderate resistance to trypsin proteolysis, but susceptible to pepsin proteolysis. The results of the study showed that several characteristics of recombinant phytase were slightly different from the native enzyme. Unfavourable characteristics such as reduced pH stability and metal ion effects should be taken into consideration during feed enzyme formulation.

关键词： phytase cloning recombinant escherichia coli Mitsuokella jalaludinii