Journal of Microbiology

Journal Articles

Rab27b regulates extracellular vesicle production in cells infected with Kaposi’s sarcoma–associated herpesvirus to promote cell survival and persistent infection: Hyungtaek Jeon , Su-Kyung Kang , Myung-Ju Lee , Changhoon Park , Seung-Min Yoo , Yun Hee Kang , Myung-Shin Lee; J. Microbiol. 2021;59(5):522-529. Published online April 20, 2021; DOI: https://doi.org/10.1007/s12275-021-1108-6

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Extracellular vesicles (EVs) play a crucial role in cell-to-cell communication. EVs and viruses share several properties related to their structure and the biogenesis machinery in cells. EVs from virus-infected cells play a key role in virus spread and suppression using various loading molecules, such as viral proteins, host proteins, and microRNAs. However, it remains unclear how and why viruses regulate EV production inside host cells. The purpose of this study is to investigate the molecular mechanisms underlying EV production and their roles in Kaposi’s sarcoma-associated herpesvirus (KSHV)-infected cells. Here, we found that KSHV induced EV production in human endothelial cells via Rab- 27b upregulation. The suppression of Rab27b expression in KSHV-infected cells enhanced cell death by increasing autophagic flux and autolysosome formation. Our results indicate that Rab27b regulates EV biogenesis to promote cell survival and persistent viral infection during KSHV infection, thereby providing novel insights into the crucial role of Rab- 27b in the KSHV life cycle.

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Engineered small extracellular vesicles as a novel platform to suppress human oncovirus-associated cancers
Iman Owliaee, Mehran khaledian, Armin Khaghani Boroujeni, Ali Shojaeian
Infectious Agents and Cancer.2023;[Epub] CrossRef
HMGB1, a potential regulator of tumor microenvironment in KSHV-infected endothelial cells
Myung-Ju Lee, Joohee Park, Seokjoo Choi, Seung-Min Yoo, Changhoon Park, Hong Seok Kim, Myung-Shin Lee
Frontiers in Microbiology.2023;[Epub] CrossRef
Alpha-2-macroglobulin as a novel diagnostic biomarker for human bladder cancer in urinary extracellular vesicles
Jisu Lee, Hyun Sik Park, Seung Ro Han, Yun Hee Kang, Ji Young Mun, Dong Wook Shin, Hyun-Woo Oh, Yoon-Kyoung Cho, Myung-Shin Lee, Jinsung Park
Frontiers in Oncology.2022;[Epub] CrossRef
Long non-coding RNAs in Sus scrofa ileum under starvation stress
Shu Wang, Yi Jia Ma, Yong Shi Li, Xu Sheng Ge, Chang Lu, Chun Bo Cai, Yang Yang, Yan Zhao, Guo Ming Liang, Xiao Hong Guo, Guo Qing Cao, Bu Gao Li, Peng Fei Gao
Animal Bioscience.2022; 35(7): 975. CrossRef

An efficient Agrobacterium-mediated transformation method for aflatoxin generation fungus Aspergillus flavus: Guomin Han , Qian Shao , Cuiping Li , Kai Zhao , Li Jiang , Jun Fan , Haiyang Jiang , Fang Tao; J. Microbiol. 2018;56(5):356-364. Published online May 2, 2018; DOI: https://doi.org/10.1007/s12275-018-7349-3

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Abstract

Aspergillus flavus often invade many important corps and produce harmful aflatoxins both in preharvest and during storage stages. The regulation mechanism of aflatoxin biosynthesis in this fungus has not been well explored mainly due to the lack of an efficient transformation method for constructing a genome-wide gene mutant library. This challenge was resolved in this study, where a reliable and efficient Agrobacterium tumefaciens-mediated transformation (ATMT) protocol for A. flavus NRRL 3357 was established. The results showed that removal of multinucleate conidia, to collect a homogenous sample of uninucleate conidia for use as the transformation material, is the key step in this procedure. A. tumefaciens strain AGL-1 harboring the ble gene for zeocin resistance under the control of the gpdA promoter from A. nidulans is suitable for genetic transformation of this fungus. We successfully generated A. flavus transformants with an efficiency of ~ 60 positive transformants per 106 conidia using our protocol. A small-scale insertional mutant library (~ 1,000 mutants) was constructed using this method and the resulting several mutants lacked both production of conidia and aflatoxin biosynthesis capacity. Southern blotting analysis demonstrated that the majority of the transformants contained a single T-DNA insert on the genome. To the best of our knowledge, this is the first report of genetic transformation of A. flavus via ATMT and our protocol provides an effective tool for construction of genome-wide gene mutant libraries for functional analysis of important genes in A. flavus.

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Agrobacterium tumefaciens-mediated transformation for the genetic modification of the biotechnologically relevant fungus Aspergillus vadensis through synthetic biology
Carolina Ropero-Pérez, Paloma Manzanares, Jose F. Marcos, Sandra Garrigues
Current Research in Biotechnology.2024; 7: 100178. CrossRef
Development of Green Fluorescent Protein-Tagged Strains of Fusarium acuminatum via PEG-Mediated Genetic Transformation
Fangyi Ju, Zhongqiang Qi, Jiajin Tan, Tingting Dai
Microorganisms.2024; 12(12): 2427. CrossRef
An efficient targeted gene deletion approach for Cochliobolus heterostrophus using Agrobacterium tumefaciens-mediated transformation
Jiaying Sun, Rui Yang, Yujia Liu, Zengran Zhou, Jiaqi Jia, Hongming Huang, Shuqin Xiao, Chunsheng Xue
Journal of Microbiological Methods.2024; 216: 106863. CrossRef
Establishment of an Agrobacterium tumefaciens-Mediated Transformation System for Hirsutella sinensis
Lijuan Wu, Xinkun Hu, Shen Yan, Zenglin Wu, Xuzhong Tang, Lei Xie, Yujie Qiu, Rui Li, Ji Chen, Mengliang Tian
Current Issues in Molecular Biology.2024; 46(9): 10618. CrossRef
Role of Flavohemoglobins in the Development and Aflatoxin Biosynthesis of Aspergillus flavus
Xiaoling Zhou, Dongyue Chen, Min Yu, Yuan Jiao, Fang Tao
Journal of Fungi.2024; 10(6): 437. CrossRef
HacA, a key transcription factor for the unfolded protein response, is required for fungal development, aflatoxin biosynthesis and pathogenicity of Aspergillus flavus
Min Yu, Xiaoling Zhou, Dongyue Chen, Yuan Jiao, Guomin Han, Fang Tao
International Journal of Food Microbiology.2024; 417: 110693. CrossRef
Synthetic Biology Tools for Engineering Aspergillus oryzae
Hui Yang, Chaonan Song, Chengwei Liu, Pengchao Wang
Journal of Fungi.2024; 10(1): 34. CrossRef
Construction of Cordycepin High-Production Strain and Optimization of Culture Conditions
Hui Zhang, Ping Chen, Lin Xu, De Xu, Wendi Hu, Yong Cheng, Shengli Yang
Current Microbiology.2023;[Epub] CrossRef
Agrobacterium tumefaciens-mediated transformation of Nigrospora sp. isolated from switchgrass leaves and antagonistic toward plant pathogens
Summi Dutta, Gabriella Houdinet, Gitanjali NandaKafle, Arjun Kafle, Christine V. Hawkes, Kevin Garcia
Journal of Microbiological Methods.2023; 215: 106849. CrossRef
Systematic Characterization of bZIP Transcription Factors Required for Development and Aflatoxin Generation by High-Throughput Gene Knockout in Aspergillus flavus
Qianqian Zhao, Hao Pei, Xiaoling Zhou, Kai Zhao, Min Yu, Guomin Han, Jun Fan, Fang Tao
Journal of Fungi.2022; 8(4): 356. CrossRef
Homologous Expression and Characterization of α-L-rhamnosidase from Aspergillus niger for the Transformation of Flavonoids
Hangyu Ye, Xiaojun Li, Luyuan Li, Yinjun Zhang, Jianyong Zheng
Applied Biochemistry and Biotechnology.2022; 194(8): 3453. CrossRef
Genetic Manipulation and Transformation Methods for Aspergillus spp.
Ye-Eun Son, Hee-Soo Park
Mycobiology.2021; 49(2): 95. CrossRef
Homologous overexpression of genes in Cordyceps militaris improves the production of polysaccharides
Yifeng Wang, Xi Yang, Ping Chen, Shengli Yang, Hui Zhang
Food Research International.2021; 147: 110452. CrossRef
A Novel Site-Specific Integration System for Genetic Modification of Aspergillus flavus
Fang Tao, Kai Zhao, Qianqian Zhao, Fangzhi Xiang, Guomin Han
G3 Genes|Genomes|Genetics.2020; 10(2): 605. CrossRef
Identification of antibiotics for use in selection of the chytrid fungi Batrachochytrium dendrobatidis and Batrachochytrium salamandrivorans
Kristyn A. Robinson, Mallory Dunn, Shane P. Hussey, Lillian K. Fritz-Laylin, Louise A. Rollins-Smith
PLOS ONE.2020; 15(10): e0240480. CrossRef
Aromatic Polyketides from a Symbiotic Strain Aspergillus fumigatus D and Characterization of Their Biosynthetic Gene D8.t287
Yi Hua, Rui Pan, Xuelian Bai, Bin Wei, Jianwei Chen, Hong Wang, Huawei Zhang
Marine Drugs.2020; 18(6): 324. CrossRef
An optimized Agrobacterium tumefaciens-mediated transformation system for random insertional mutagenesis in Fonsecaea monophora
Xing Xiao, Yu Li, JingLin Qin, Ya He, Wenying Cai, Zhiwen Chen, Liyan Xi, Junmin Zhang
Journal of Microbiological Methods.2020; 170: 105838. CrossRef
Genome-wide association study leads to novel genetic insights into resistance to Aspergillus flavus in maize kernels
Guomin Han, Cuiping Li, Fangzhi Xiang, Qianqian Zhao, Yang Zhao, Ronghao Cai, Beijiu Cheng, Xuewen Wang, Fang Tao
BMC Plant Biology.2020;[Epub] CrossRef
The Efficacy of Composite Essential Oils against Aflatoxigenic Fungus Aspergillus flavus in Maize
Fangzhi Xiang, Qianqian Zhao, Kai Zhao, Hao Pei, Fang Tao
Toxins.2020; 12(9): 562. CrossRef
Ethylene and Benzaldehyde Emitted from Postharvest Tomatoes Inhibit Botrytis cinerea via Binding to G-Protein Coupled Receptors and Transmitting with cAMP-Signal Pathway of the Fungus
Yongwen Lin, Hongchun Ruan, Komivi Senyo Akutse, Baochun Lai, Yizhang Lin, Youming Hou, Fenglin Zhong
Journal of Agricultural and Food Chemistry.2019; 67(49): 13706. CrossRef

Research Support, Non-U.S. Gov'ts

Identification of seven novel virulence genes from Xanthomonas citri subsp. citri by Tn5-based random mutagenesis: Xue Song , Jing Guo , Wen-xiu Ma , Zhi-yuan Ji , Li-fang Zou , Gong-you Chen , Hua-song Zou; J. Microbiol. 2015;53(5):330-336. Published online May 3, 2015; DOI: https://doi.org/10.1007/s12275-015-4589-3

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Abstract

To identify novel virulence genes, a mutant library of Xanthomonas citri subsp. citri 29-1 was produced using EZ-Tn5 transposon and the mutants were inoculated into susceptible grapefruit. Forty mutants with altered virulence phenotypes were identified. Nine of the mutants showed a complete loss of citrus canker induction, and the other 31 mutants resulted in attenuated canker symptoms. Southern blot analysis revealed that each of the mutants carried a single copy of Tn5. The flanking sequence was identified by plasmid rescue and 18 different ORFs were identified in the genome sequence. Of these 18 ORFs, seven had not been previously associated with the virulence of X. citri subsp. citri and were therefore confirmed by complementation analysis. Real-time PCR analysis showed that the seven genes were upregulated when the bacteria were grown in citrus plants, suggesting that the expression of these genes was essential for canker development.

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Xanthomonas citri subsp. citri type III effector PthA4 directs the dynamical expression of a putative citrus carbohydrate-binding protein gene for canker formation
Xinyu Chen, Huasong Zou, Tao Zhuo, Wei Rou, Wei Wu, Xiaojing Fan
eLife.2024;[Epub] CrossRef
The Methyltransferase HemK Regulates the Virulence and Nutrient Utilization of the Phytopathogenic Bacterium Xanthomonas citri Subsp. citri
Yu Shi, Xiaobei Yang, Xiaoxin Ye, Jiaying Feng, Tianfang Cheng, Xiaofan Zhou, Ding Xiang Liu, Linghui Xu, Junxia Wang
International Journal of Molecular Sciences.2022; 23(7): 3931. CrossRef
A Comprehensive Overview of the Genes and Functions Required for Lettuce Infection by the Hemibiotrophic Phytopathogen Xanthomonas hortorum pv. vitians
Lucas Morinière, Laurène Mirabel, Erwan Gueguen, Franck Bertolla, Christopher W. Schadt, Steven Lindow
mSystems.2022;[Epub] CrossRef
Identification of Essential Genes Associated With Prodigiosin Production in Serratia marcescens FZSF02
Xianbo Jia, Fangchen Liu, Ke Zhao, Junjie Lin, Yu Fang, Shouping Cai, Chenqiang Lin, Hui Zhang, Longjun Chen, Jichen Chen
Frontiers in Microbiology.2021;[Epub] CrossRef
An inducible transposon mutagenesis approach for the intracellular human pathogen Chlamydia trachomatis
Colette E. O'Neill, Rachel J. Skilton, Jade Forster, David W. Cleary, Sarah A. Pearson, David J. Lampe, Nicholas R. Thomson, Ian N. Clarke
Wellcome Open Research.2021; 6: 312. CrossRef
The carB Gene of Escherichia coli BL21(DE3) is Associated with Nematicidal Activity against the Root-Knot Nematode Meloidogyne javanica
Yanfei Xia, Shen Li, Guohui Xu, Shanshan Xie, Xueting Liu, Xiaomin Lin, Huijun Wu, Xuewen Gao
Pathogens.2021; 10(2): 222. CrossRef
Comparing bacterial properties in relation to the virulence factors of Xanthomonas citri subsp. citri strains and evaluating resistance of subtribe Citrinae cultivars to the most virulent strain
Hossein Mirzaei-Najafgholi, Milad Aeini, Saeed Tarighi, Morteza Golmohammadi
Journal of Plant Pathology.2021; 103(2): 449. CrossRef
Inhibition of the Citrus Canker Pathogen Using a Photosensitizer Assisted by Sunlight Irradiation
Libin Jiang, Yurong Liu, Xianyuan Xu, Dan Su, Huasong Zou, Jianyong Liu, Cai Yuan, Mingdong Huang
Frontiers in Microbiology.2020;[Epub] CrossRef
Tn5 Transposase Applied in Genomics Research
Niannian Li, Kairang Jin, Yanmin Bai, Haifeng Fu, Lin Liu, Bin Liu
International Journal of Molecular Sciences.2020; 21(21): 8329. CrossRef
A practical random mutagenesis system for Ralstonia solanacearum strains causing bacterial wilt of Pogostemon cablin using Tn5 transposon
Yaqin Wang, Yuyao Zhang, Hua Jin, Zhicheng Deng, Zhuan Li, Yanzhen Mai, Guangwei Li, Hong He
World Journal of Microbiology and Biotechnology.2019;[Epub] CrossRef
Global Regulator PhoP is Necessary for Motility, Biofilm Formation, Exoenzyme Production, and Virulence of Xanthomonas citri Subsp. citri on Citrus Plants
Chudan Wei, Tian Ding, Changqing Chang, Chengpeng Yu, Xingwei Li, Qiongguang Liu
Genes.2019; 10(5): 340. CrossRef
The ColRS-Regulated Membrane Protein Gene XAC1347 Is Involved in Copper Homeostasis and hrp Gene Expression in Xanthomonas citri subsp. citri
Xiaojing Fan, Jing Guo, Yinghui Zhou, Tao Zhuo, Xun Hu, Huasong Zou
Frontiers in Microbiology.2018;[Epub] CrossRef
Salmonella Persistence in Tomatoes Requires a Distinct Set of Metabolic Functions Identified by Transposon Insertion Sequencing
Marcos H. de Moraes, Prerak Desai, Steffen Porwollik, Rocio Canals, Daniel R. Perez, Weiping Chu, Michael McClelland, Max Teplitski, Harold L. Drake
Applied and Environmental Microbiology.2017;[Epub] CrossRef
Identification of New Genes Related to Virulence of <i>Xanthomonas axonopodis</i> Pv. <i>Citri</i> during Citrus Host Interactions
Cristiano B. Ferreira, Leandro M. Moreira, Joice B. Brigati, Lonjoré L. Lima, Jesus A. Ferro, Maria I. T. Ferro, Julio C. F. de Oliveira
Advances in Microbiology.2017; 07(01): 22. CrossRef
Identification of an Extracellular Endoglucanase That Is Required for Full Virulence in Xanthomonas citri subsp. citri
Tian Xia, Yanjiao Li, Dongling Sun, Tao Zhuo, Xiaojing Fan, Huasong Zou, Zonghua Wang
PLOS ONE.2016; 11(3): e0151017. CrossRef
The sigma 54 genes rpoN1 and rpoN2 of Xanthomonas citri subsp. citri play different roles in virulence, nutrient utilization and cell motility
Gibson Kamau Gicharu, Dong-ling SUN, Xun HU, Xiao-jing FAN, Tao ZHUO, Chuan-wan WU, Hua-song ZOU
Journal of Integrative Agriculture.2016; 15(9): 2032. CrossRef

A Potent Brucella abortus 2308 Δery Live Vaccine Allows for the Differentiation between Natural and Vaccinated Infection: Junbo Zhang , Shuanghong Yin , Fei Guo , Ren Meng , Chuangfu Chen , Hui Zhang , Zhiqiang Li , Qiang Fu , Huijun Shi , Shengwei Hu , Wei Ni , Tiansen Li , Ke Zhang; J. Microbiol. 2014;52(8):681-688. Published online July 4, 2014; DOI: https://doi.org/10.1007/s12275-014-3689-9

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Abstract

Brucellosis is a globally distributed zoonotic disease that causes animal and human diseases. However, the current Brucella abortus vaccines (S19 and RB51) are deficient; they can cause abortion in pregnant animals. Moreover, when the vaccine S19 is used, tests cannot differentiate natural from vaccinated infection. Therefore, a safer and more potent vaccine is needed. A Brucella abortus 2308 ery promoter mutant (Δery) was constructed to overcome these drawbacks. The growth of the Δery mutant was significantly attenuated in macrophages and mice and induced high protective immunity in mice. Moreover, Δery induced an anti-Brucellaspecific IgG (immunoglobulin G) response and stimulated the expression of interferon-gamma (INF-γ) and interleukin-4 (IL-4). Furthermore, the expression of EryA antigen allowed for the serological differentiation between natural and vaccinated infection in mice. These results indicate that the Δery mutant is a potential attenuated live vaccine candidate against virulent Brucella abortus 2308 (S2308) infection.

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Disruption of Erythritol Catabolism via the Deletion of Fructose-Bisphosphate Aldolase (Fba) and Transaldolase (Tal) as a Strategy to Improve the Brucella Rev1 Vaccine
Aitor Elizalde-Bielsa, Leticia Lázaro-Antón, María Jesús de Miguel, Pilar M. Muñoz, Raquel Conde-Álvarez, Amaia Zúñiga-Ripa
International Journal of Molecular Sciences.2024; 25(20): 11230. CrossRef
Establishment of picodroplet-based co-culture system to improve erythritol production in Yarrowia lipolytica
Shuang Li, Yuan Zhang, Lu Li, Yaomeng Yuan, Haoxuan Sun, Xin-Hui Xing, Xiaoyan Wang, Chong Zhang
Biochemical Engineering Journal.2023; 198: 109036. CrossRef
Characterization of Brucella abortus Mutant A19mut2, a Potential DIVA Vaccine Candidate with a Modification on Lipopolysaccharide
Hosny Ahmed Abdelgawad, Zhengmin Lian, Yi Yin, Tian Fang, Mingxing Tian, Shengqing Yu
Vaccines.2023; 11(7): 1273. CrossRef
Evaluation of Brucellosis Vaccines: A Comprehensive Review
Mohsen Heidary, Shirin Dashtbin, Roya Ghanavati, Marzie Mahdizade Ari, Narjess Bostanghadiri, Atieh Darbandi, Tahereh Navidifar, Malihe Talebi
Frontiers in Veterinary Science.2022;[Epub] CrossRef
Advances and prospects of transcription‐factor‐based biosensors in high‐throughput screening for cell factories construction
Changfan Li, Chang Wang, Jiang Zhu, Feng Xue, Xiaoman Sun, Yang Gu
Food Bioengineering.2022; 1(2): 135. CrossRef
Development of Brucella melitensis Rev.1 ΔOmp19 mutants with DIVA feature and comparison of their efficacy against three commercial vaccines in a mouse model
Ali Uslu, Osman Erganis
Molecular Immunology.2021; 133: 44. CrossRef
Insights into irr and rirA gene regulation on the virulence of Brucella melitensis M5-90
Huan Zhang, Benben Wang, Wenxing Wu, Xiaoyu Deng, Zhiran Shao, Jihai Yi, Zhen Wang, Ningning Yang, Yong Wang, Yuanzhi Wang, Chuangfu Chen
Canadian Journal of Microbiology.2020; 66(5): 351. CrossRef
Combining genetically-encoded biosensors with high throughput strain screening to maximize erythritol production in Yarrowia lipolytica
Xueliang Qiu, Peng Xu, Xinrui Zhao, Guocheng Du, Juan Zhang, Jianghua Li
Metabolic Engineering.2020; 60: 66. CrossRef
Research progress on the role of immune cells in Brucella infection
Jin Zhang
Infection International.2018; 7(1): 23. CrossRef
Development and evaluation of in murine model, of an improved live-vaccine candidate against brucellosis from to Brucella melitensis vjbR deletion mutant
Zhiqiang Li, Shuli Wang, Hui Zhang, Li Xi, Jinliang Zhang, Xiaogen Zhang, Qingfeng Zhou, Jihai Yi, Min Li, Weihua Zhang, Junbo Zhang
Microbial Pathogenesis.2018; 124: 250. CrossRef
Expression and regulation of the ery operon of Brucella melitensis in human trophoblast cells
Hui Zhang, Xiaoxia Dou, Zhiqiang Li, Yu Zhang, Jing Zhang, Fei Guo, Yuanzhi Wang, Zhen Wang, Tiansen Li, Xinli Gu, Chuangfu Chen
Experimental and Therapeutic Medicine.2016; 12(4): 2723. CrossRef
Protection efficacy of the Brucella abortus ghost vaccine candidate lysed by the N-terminal 24-amino acid fragment (GI24) of the 36-amino acid peptide PMAP-36 (porcine myeloid antimicrobial peptide 36) in murine models
Ae Jeong KWON, Ja Young MOON, Won Kyong KIM, Suk KIM, Jin HUR
Journal of Veterinary Medical Science.2016; 78(10): 1541. CrossRef
Meta-Analysis and Advancement of Brucellosis Vaccinology
Tatiane F. Carvalho, João Paulo A. Haddad, Tatiane A. Paixão, Renato L. Santos, Roy Martin Roop
PLOS ONE.2016; 11(11): e0166582. CrossRef
The Brucella melitensis M5-90 phosphoglucomutase (PGM) mutant is attenuated and confers protection against wild-type challenge in BALB/c mice
Yu Zhang, Tiansen Li, Jing Zhang, Zhiqiang Li, Yan Zhang, Zhen Wang, Hanping Feng, Yuanzhi Wang, Chuangfu Chen, Hui Zhang
World Journal of Microbiology and Biotechnology.2016;[Epub] CrossRef
A Brucella melitensis M5-90 wboA deletion strain is attenuated and enhances vaccine efficacy
Zhi-Qiang Li, Jing-Xue Shi, Wen-Dong Fu, Yu Zhang, Jing Zhang, Zhen Wang, Tian-Sen Li, Chuang-Fu Chen, Fei Guo, Hui Zhang
Molecular Immunology.2015; 66(2): 276. CrossRef

Functional Analysis of pilQ Gene in Xanthomanas oryzae pv. oryzae, Bacterial Blight Pathogen of Rice: Seon-Hwa Lim , Byoung-Ho So , Ji-Chun Wang , Eun-Seong Song , Young-Jin Park , Byoung-Moo Lee , Hee-Wan Kang; J. Microbiol. 2008;46(2):214-220. Published online June 11, 2008; DOI: https://doi.org/10.1007/s12275-007-0173-9

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Abstract: Bacterial blight (BB) of rice, caused by Xanthomonas oryzae pv. oryzae (Xoo), is the most devastating bacterial disease in rice. A virulence-attenuated mutant strain HNU89K9 of X. oryzae pv. oryzae (KACC10331), with a transposon insertion in the pilQ gene was used for this study. The pilQ was involved in the gene cluster pilMNOPQ of the Xoo genome. Growth rate of the pilQ mutant was similar to that of wild-type. At level of amino acids, PilQ of Xoo showed that a high sequence identities more than 94% and 70% to Xanthomonas species and to Xyllela fastidiosa, respectively but a low sequence homology less than 30% to other bacterial species. The twitching motility forming a marginal fringe on PSA media was observed on colony of the wild-type strain KACC10331, but not in mutant HNU89K9. Wild-type Xoo cells formed a biofilm on the surface of the PVC plastic test tube, while the mutant strain HNU89K9 did not form a biofilm. The results suggest that the pilQ gene of X. oryzae pv. oryzae plays a critical role in pathogenicity, twitching motility, and biofilm formation.

Strain Improvement of Candida tropicalis for the Production of Xylitol:Biochemical and Physiological Characterization of Wild-type and Mutant Strain CT-OMV5: Ravella Sreenivas Rao , Cherukuri Pavana Jyothi , Reddy Shetty Prakasham , Chaganti Subba Rao , Ponnupalli Nageshwara Sarma , Linga Venkateswar Rao; J. Microbiol. 2006;44(1):113-120.; DOI: https://doi.org/2328 [pii]

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Abstract: Candida tropicalis was treated with ultraviolet (UV) rays, and the mutants obtained were screened for xylitol production. One of the mutants, the UV1 produced 0.81g of xylitol per gram of xylose. This was further mutated with N-methyl-N’-nitro-N-nitrosoguanidine (MNNG), and the mutants obtained were screened for xylitol production. One of the mutants (CT-OMV5) produced 0.85g/g of xylitol from xylose. Xylitol production improved to 0.87 g/g of xylose with this strain when the production medium was supplemented with urea. The CT-OMV5 mutant strain differs by 12 tests when compared to the wild-type Candida tropicalis strain. The XR activity was higher in mutant CT-OMV5. The distinct difference between the mutant and wild-type strain is the presence of numerous chlamydospores in the mutant. In this investigation, we have demonstrated that mutagenesis was successful in generating a superior xylitol-producing strain, CT-OMV5, and uncovered distinctive biochemical and physiological characteristics of the wild-type and mutant strain, CT-OMV5.

Screening of Growth- or Development-related Genes by Using Genomic Library with Inducible Promoter in Aspergillus nidulans: Bang-Yong Lee , Sang-Yong Han , Han Gil Choi , Jee Hyun Kim , Kap-Hoon Han , Dong-Min Han; J. Microbiol. 2005;43(6):523-528.; DOI: https://doi.org/2295 [pii]

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Abstract: Using the genomic library constructed at the downstream of the niiA promoter, which induces the over-expression of an inserted DNA fragment, we have attempted to screen the genes affecting growth or development by over-expression. The wild-type strain was transformed using the AMA-niiA(p) library and cultured on 1.2 M sorbitol media, in which asexual sporulation is induced, but sexual development is repressed. Over 100,000 strains transformed to pyrG+ were analyzed with regard to any changes in phenotype. Consequently, seven strains were isolated for further analyses. These strains were designated NOT [niiA(p) over-expression transformants] stains. Four of the strains were of the inducible type, and the remaining strains were of the multi-copy suppression type. Two of the inducible-type strains, NOT1 and NOT40, harbored genes which had been inserted in reverse direction, suggesting that the mutant phenotypes had been derived from an excess amount of anti-sense mRNA. Domain analyses of the deduced polypeptides from the DNA fragments rescued from the transformants revealed that NOT1, NOT40 and NOT6 harbored a LisH motif, a forkhead domain, and a Zn(II)2Cys6 binuclear zinc cluster, respectively.

Isolation and Genetic Mapping of Paraquat-Resistant Sporulating Mutants of Streptomyces Coelicolor: Chung, Hye Jung , Kim, Eun Ja , Park, Uhn Mee , Roe, Jung Hye; J. Microbiol. 1995;33(3):215-221.

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Abstract: S. coelicolor A3(2) cells were treated with various redox-cycling agents on nutrient agar plates and examined for their effect on the growth and differentiation. When treated with plumbagin, severe effect on cell viability was observed at concentrations above 250 uM. However, the surviving colonies differentiated normally. When treated with 100 uM paraquat, growth rate was decreased and morphological differentiation was inhibited, while the survival rate was maintained at about 100% even at 5 mM paraquat. Menadione or lawsone did not cause any visible changes at concentrations up to 1 mM. The effect of paraquat was also observed when it was added to nutrient agar plate before spore inoculation. Paraquat had also observed when it was added to nutrient agar plate before spore inoculation. Paraquat had no effect on colonies growing on R2YE agar plates. Among the components of R2YE medium selectively added to nutrient agar medium, CaCl₂was found to have some protective function from the inhibitory effect of paraquat. As a first step to study the mechanism of the inhibitory effect of paraquat on differentiation, resistant mutants which sporulate well in the presence of paraquat were screened following UV mutagenesis. Three paraquat-resistant mutants were isolated with a frequency of 3 × 10^-5. Their mutation sites were determined by genetic crossings. All three mutations were mapped to a single locus near argA at about 1 o'clock on the genetic map of S. coelicolor A3(2).

cloning of Gene Encoding for Siderophore biosynthesis in Fluorescent Pseudomonas sp.: Koh, Han Cheol , Ha, Sung Cheol , Na, Jung A , Kim, Ho Sang , Yeo, Myeong Gu , Lee, Jung Sup , Kim, Sung Jun , Park, yeal; J. Microbiol. 1995;33(1):28-33.

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Abstract: Pseudomonas sp. strain PY002, isolated from soil, was mutagenized with a transposon Tn5(21). To screening of siderophore biosunthesis defective mutant, 138 kanamycin resistant mutants were tested of growth on MKB medium supplemented with iron chelator(bipydidyl and EDDHA) and in vitro antibiosis. Among 138 mutants, 32 mutants do not excreted a siderophore and lose their antibiotic activity. So, these mutants were designated Flu^-Sid^-. A gene bank of DNA from Pseudomonas sp. strain PY002 was constructed using the broad-host range conjugative cosmid pLAFR3. The recombinant cosmids contained insert DNA averaging 21 kb in length and the frequence of transduction into E. coli HB101 per 1㎍ of insert DNA was 9 × 10³. Nonfluorescent mutants were complemented by mating the gene bank en masse and identifying the 108 fluorescent transconjugants. Restriction enzyme analysis of these complemented transconjugants revealed three different types and they were named pCOM61, pCOM91 and pCOM97. Sizes of their insert DNA were 30kb, 26kb and 28kb, respectively.

Isolation of Glucose Utilizing Mutant of Alcaligenes eutrophus, its Substrate Selectivity, and Accumulation of Poly-β-hydroxybutyrate: Kim, Hye Yeon , Park, Jin Seo , Shin, Hyun Dong , Lee, yong Hyun; J. Microbiol. 1995;33(1):51-58.

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Abstract: A glucose utilizing mutant was selected from parent strain Alcaligenes eutrophus H16, and named as Glu-9. The mechanisms of glucose utilization of the mutant Glu-9 was investigated by measuring the D-[1-¹⁴C] glucose transport activity and the activities of key enzymes related to glucose and fructose uptake via facilitated diffusion. The uptaken glucose seems to activate key enzymes related to glucose matabolism. The selectivity between glucose and fructose of mutant Glu-9 was also analyzed by measuring glucose transport activity and enzyme activities under the various cultivation conditions using different carbon sources. Mutant Alcaligenes eutrophus Glu-9 preferentially consumed fructose from mixed substrates of glucose and fructose due to the inhibition of fructose to glucose transport activity. The characteristics of cell growth and PHB accumulation of Alcaligenes eutrophus Glu-9 were examined under various cultural conditions. Mutant strain Glu-9 showed tolerance in high concentration of glucose and increased yield of PHB production.

Isolation and characterization of pre-tRNA^Val splicing Mutants of Schizosaccharomyces pombe: Hwang, Ku Chan , Kim, Dae Myung; J. Microbiol. 1997;35(4):334-340.

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Abstract: A collection of 132 temperature sensitive (ts) mutants was generated by the chemical mutagenesis of Schizosaccharomyces pombe wild type strain and screened for tRNA splicing defects on Northern blots by hybridization with an oligonucleotide that recognizes the exon of the S. pombe tRNA^Val as a probe. We identidied 6 mutants which accumulate precursor tRNA^Val. Among them, 2 mutants exhibited remarkable morphological differences compared to wild type cells. One tRNA splicing mutant showed elongated cell shape in permissive as well as non-permissive cultures. The other mutant exhibited shortened cell morphology only in nonpermissive culture. The total RNA pattern in the splicing mutants appeared to be normal. Genetic analysis of four tRNA^Val splicing mutants demonstrated that the mutation reside in different genes.

Factors affecting pheromone induction of schizosaccharomyces pomba and isolation of pheromone induction mutants: Jun, Jai Hyun , Kim, Young Min , Lee, Joo Hun , Chung, In Kwon , Kim, Dae Myung; J. Microbiol. 1998;36(3):196-202.

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Abstract: The mating pheromones of Schizosaccharomyces pombe are induced by nutritional starvation. However, this nutritional signaling pathway is largely unknown. For a complete understanding of pheromone induction, we examined the environmental factors affecting the induction afer cells were transferred to a nitrogen-starved medium. It appeared that the induction of mfm2 transcription was affected by the general environmental stress including incubation time, incubation temperature, and the growth phase of the cells. We identified 7 pheromone induction mutants by screening temperature sensitive mutant bank. Three of these mutants showed elongated cell shapes and one mutant exhibited swollen cell morphology in permissive culture, suggesting that their cell cycles were also impaired. Characterization of the pheromone induction mutants may elucidate the components required in nutritional signaling pathway leading to pheromone induction.

Isolation of the Regulator Gene Responsible for Overproduction of Catalase A in H 2 O 2 -resistant Mutant of Streptomyces coelicolor: Ji-Sook Hahn , So-Young Oh , Keith F. Chater , Jung-Hye Roe; J. Microbiol. 2000;38(1):18-23.

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Abstract: Streptomyces coelicolor produces three kinds of catalases to cope with oxidative stress and to allow nor-mal differentiation. Catalase A is the major vegetative catalase which functions in removing hydrogen peroxide generated during the process of aerobic metabolism. To understand the regulatory mechanism of response against oxidative stress, hydrogen peroxide-resistant mutant (HR40) was isolated from S. coelicolor J1501 following UV mutagenesis. The mutant overproduced catalase A more than 50-fold compared with the wild type. The mutation locus catR1 was mapped closed to the mthB2 locus by genetic crossings. An ordered cosmid library of S. coelicolor encompassing the mthB2 locus was used to isolate the regulator gene (catR) which represses catalase overproduction when introduced into HR40. A candidate catR gene was found to encode a Fur-like protein of 138 amino acids (15319 Da).

Energy Status of Neurospora crassa Mutant nap in Relation to Accumulation of Carotenoids: Tatyana A. Belozerskaya^ , Tatyana V. Potapova^† , Elena P. Isakova , Eugene I. Shurubor , Ludmila V. Savel'eva , Renata A. Zvyagilskaya; J. Microbiol. 2003;41(1):41-45.

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Abstract: N. crassa mutant strain nap showed reduced growth rate, decreased electric membrane potential, and elevated intracellular ATP content in comparison to the wild type. Blue light induced a hyperpolarization of the membrane potential in both strains. The analysis of oxidative and phosphorylation activities of mitochondria isolated from the two strains has revealed that nap utilized more efficient oxidative pathways. The higher intracellular ATP content in the nap was presumably due to impaired transport systems of the plasma membrane, and to a lesser extent to the functioning of the fully competent respiratory chain. The excess ATP possibly accounts for carotenoid accumulation in the mutant.

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