Journal of Microbiology

Journal Articles

Comparison of Ganoderma boninense Isolate’s Aggressiveness Using Infected Oil Palm Seedlings: Mei Lieng Lo , Tu Anh Vu Thanh , Frazer Midot , Sharon Yu Ling Lau , Wei Chee Wong , Hun Jiat Tung , Mui Sie Jee , Mei-Yee Chin , Lulie Melling; J. Microbiol. 2023;61(4):449-459. Published online April 25, 2023; DOI: https://doi.org/10.1007/s12275-023-00040-w

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Basal stem rot incidence caused by a white-rot fungus, Ganoderma boninense, is the major disease of oil palm in Southeast Asia. The rate of disease transmission and host damage are affected by variations in pathogen aggressiveness. Several other studies have used the disease severity index (DSI) to determine G. boninense aggressiveness levels while verifying disease using a culture-based method, which might not provide accurate results or be feasible in all cases. To differentiate G. boninense aggressiveness, we employed the DSI and vegetative growth measurement of infected oil palm seedlings. Disease confirmation was performed through scanning electron microscopy and molecular identification of fungal DNA from both infected tissue and fungi isolated from Ganoderma selective medium. Two-month-old oil palm seedlings were artificially inoculated with G. boninense isolates (2, 4A, 5A, 5B, and 7A) sampled from Miri (Lambir) and Mukah (Sungai Meris and Sungai Liuk), Sarawak. The isolates were categorized into three groups: highly aggressive (4A and 5B), moderately aggressive (5A and 7A), and less aggressive (2). Isolate 5B was identified as the most aggressive, and it was the only one to result in seedling mortality. Out of the five vegetative growth parameters measured, only the bole size between treatments was not affected. The integration of both conventional and molecular approaches in disease confirmation allows for precise detection.

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An In-Depth Study of Phytopathogenic Ganoderma: Pathogenicity, Advanced Detection Techniques, Control Strategies, and Sustainable Management
Samantha C. Karunarathna, Nimesha M. Patabendige, Wenhua Lu, Suhail Asad, Kalani K. Hapuarachchi
Journal of Fungi.2024; 10(6): 414. CrossRef
Advancements in the nanodelivery of azole-based fungicides to control oil palm pathogenic fungi
Azren Aida Asmawi, Fatmawati Adam, Nurul Aini Mohd Azman, Mohd Basyaruddin Abdul Rahman
Heliyon.2024; 10(18): e37132. CrossRef
Characterizations of Ganoderma species causing basal stem rot disease in coconut tree
Umesh Sajjan, Manjunath Hubballi, Abhay K. Pandey, V. Devappa, H. P. Maheswarappa
3 Biotech.2024;[Epub] CrossRef

The inability of Bacillus licheniformis perR mutant to grow is mainly due to the lack of PerR-mediated fur repression: Jung-Hoon Kim , Yoon-Mo Yang , Chang-Jun Ji , Su-Hyun Ryu , Young-Bin Won , Shin-Yeong Ju , Yumi Kwon , Yeh-Eun Lee , Hwan Youn , Jin-Won Lee; J. Microbiol. 2017;55(6):457-463. Published online April 22, 2017; DOI: https://doi.org/10.1007/s12275-017-7051-x

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Abstract

PerR, a member of Fur family protein, is a metal-dependent H2O2 sensing transcription factor that regulates genes in-volved in peroxide stress response. Industrially important bac-terium Bacillus licheniformis contains three PerR-like pro-teins (PerRBL, PerR2, and PerR3) compared to its close rela-tive Bacillus subtilis. Interestingly, unlike other bacteria in-cluding B. subtilis, no authentic perRBL null mutant could be established for B. licheniformis. Thus, we constructed a con-ditional perRBL mutant using a xylose-inducible promoter, and investigated the genes under the control of PerRBL. PerRBL regulon genes include katA, mrgA, ahpC, pfeT, hemA, fur, and perR as observed for PerRBS. However, there is some variation in the expression levels of fur and hemA genes be-tween B. subtilis and B. licheniformis in the derepressed state. Furthermore, katA, mrgA, and ahpC are strongly induced, whereas the others are only weakly or not induced by H2O2 treatment. In contrast to the B. subtilis perR null mutant which frequently gives rise to large colony phenotype mainly due to the loss of katA, the suppressors of B. licheniformis perR mutant, which can form colonies on LB agar, were all cata-lase-positive. Instead, many of the suppressors showed in-creased levels of siderophore production, suggesting that the suppressor mutation is linked to the fur gene. Consistent with this, perR fur double mutant could grow on LB agar without Fe supplementation, whereas perR katA double mutant could only grow on LB agar with Fe supplementation. Taken toge-ther, our data suggest that in B. licheniformis, despite the si-milarity in PerRBL and PerRBS regulon genes, perR is an essen-tial gene required for growth and that the inability of perR null mutant to grow is mainly due to elevated expression of Fur.

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Characterization of the dual regulation by a c-di-GMP riboswitch Bc1 with a long expression platform from Bacillus thuringiensis
Lu Liu, Dehua Luo, Yongji Zhang, Dingqi Liu, Kang Yin, Qing Tang, Shan-Ho Chou, Jin He, Beile Gao
Microbiology Spectrum.2024;[Epub] CrossRef
Meddling with Metal Sensors: Fur-Family Proteins as Signaling Hubs
Caroline H. Steingard, John D. Helmann, Tina M. Henkin
Journal of Bacteriology.2023;[Epub] CrossRef
Divergent Effects of Peptidoglycan Carboxypeptidase DacA on Intrinsic β-Lactam and Vancomycin Resistance
Si Hyoung Park, Umji Choi, Su-Hyun Ryu, Han Byeol Lee, Jin-Won Lee, Chang-Ro Lee, Krisztina M. Papp-Wallace
Microbiology Spectrum.2022;[Epub] CrossRef
Microbial Redox Regulator-Enabled Pulldown for Rapid Analysis of Plasma Low-Molecular-Weight Biothiols
Jin Oh Lee, Yoon-Mo Yang, Jae-Hoon Choi, Tae-Wuk Kim, Jin-Won Lee, Young-Pil Kim
Analytical Chemistry.2019; 91(15): 10064. CrossRef
Redox Sensing by Fe2+in Bacterial Fur Family Metalloregulators
Azul Pinochet-Barros, John D. Helmann
Antioxidants & Redox Signaling.2018; 29(18): 1858. CrossRef

Research Support, Non-U.S. Gov't

Inhibitory Effects of 4-Hydroxy-2,5-Dimethyl-3(2H)-Furanone (HDMF) on Acyl-Homoserine Lactone-Mediated Virulence Factor Production and Biofilm Formation in Pseudomonas aeruginosa PAO1: Sung-Chan Choi , Can Zhang , Sooyoung Moon , Young-Sook Oh; J. Microbiol. 2014;52(9):734-742. Published online August 2, 2014; DOI: https://doi.org/10.1007/s12275-014-4060-x

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Abstract

4-Hydroxy-2,5-dimethyl-3(2H)-furanone (HDMF), a nonhalogenated furanone found in a variety of fruits, has been shown to have antimicrobial activity. However, few studies have focused on its inhibitory effect on bacterial quorum sensing (QS) at levels below the non-inhibitory concentration. In this study, 0.1 μM HDMF decreased the production of QS signal molecules and inhibited QS-controlled biofilm formation by Pseudomonas aeruginosa PAO1 without causing growth inhibition. In the presence of 0.1 and 1.0 μM HDMF, biofilm production by PAO1 was reduced by 27.8 and 42.6%, respectively, compared to that by untreated control cells. HDMF (1.0 μM) also significantly affected virulence factor expression (regulated by the las, rhl, and pqs system), resulting in a significant reduction in the production of LasA protease (53.8%), rhamnolipid (40.9%), and pyocyanin (51.4%). This HDMF-dependent inhibition of virulence factor expression was overcome by increasing the levels of two QS signal molecules of P. aeruginosa, N-(3-oxo-dodecanoyl)-L-homoserine lactone and N-butyryl-L-homoserine lactone, suggesting reversible competitive inhibition between HDMF and these molecules. The results of this study indicate that HDMF has great potential as an inhibitor of QS, and that it may be of value as a therapeutic agent and in biofilm control, without increasing selective pressure for resistance development.

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Molecular and Phenotypic Investigation on Antibacterial Activities of Limonene Isomers and Its Oxidation Derivative against Xanthomonas oryzae pv. oryzae
Hyeonbin Kim, Mi Hee Kim, Ui-Lim Choi, Moon-Soo Chung, Chul-Ho Yun, Youngkun Shim, Jaejun Oh, Sungbeom Lee, Gun Woong Lee
Journal of Microbiology and Biotechnology.2024; 34(3): 562. CrossRef
Association Between Albumin-Bilirubin Score and Ventricular Arrhythmia in Patients with Heart Failure
Murat Oğuz Özilhan, Sadık Kadri Açıkgöz
e-Journal of Cardiovascular Medicine.2024; : 17. CrossRef
The impact of agarose immobilization on the activity of lytic Pseudomonas aeruginosa phages combined with chemicals
Agata Dorotkiewicz-Jach, Paweł Markwitz, Jarosław Rachuna, Michał Arabski, Zuzanna Drulis-Kawa
Applied Microbiology and Biotechnology.2023; 107(2-3): 897. CrossRef
Furanone loaded aerogels are effective antibiofilm therapeutics in a model of chronic Pseudomonas aeruginosa wound infection
Chris R. Proctor, Megan G. Taggart, Barry M.G. O'Hagan, Paul A. McCarron, Ronan R. McCarthy, Nigel G. Ternan
Biofilm.2023; 5: 100128. CrossRef
Plant compounds and nonsteroidal anti-inflammatory drugs interfere with quorum sensing in Chromobacterium violaceum
Erika Lorena Giraldo Vargas, Felipe Alves de Almeida, Leonardo Luiz de Freitas, Uelinton Manoel Pinto, Maria Cristina Dantas Vanetti
Archives of Microbiology.2021; 203(9): 5491. CrossRef
The In Vitro Anti-Pseudomonal Activity of Cu2+, Strawberry Furanone, Gentamicin, and Lytic Phages Alone and in Combination: Pros and Cons
Agata Dorotkiewicz-Jach, Pawel Markwitz, Zuzanna Drulis-Kawa
International Journal of Molecular Sciences.2021; 22(18): 9830. CrossRef
Furanone quorum-sensing inhibitors with potential as novel therapeutics against Pseudomonas aeruginosa
Chris R. Proctor, Paul A. McCarron, Nigel G. Ternan
Journal of Medical Microbiology.2020; 69(2): 195. CrossRef
D-Tryptophan governs biofilm formation rates and bacterial interaction in P. mendocina and S. aureus
Saheli Ghosh, Asifa Qureshi, Hemant J Purohit
Journal of Biosciences.2019;[Epub] CrossRef
Inhibitory action of essential oils against proteases activity of Paenibacillus larvae, the etiological agent of American Foulbrood disease
María C. Pellegrini, Lucía Zalazar, Sandra R. Fuselli, Alejandra G. Ponce
Spanish Journal of Agricultural Research.2018; 15(4): e0504. CrossRef
5-Hydroxy-γ-decalactone production by Bacillus sp. 1s-1 and its complete genome sequence
Zijun Xiao, Lingyan Ma, Jing-yi Zhao, Haoxuan Zhong, Yawei Sun
Journal of Biotechnology.2018; 286: 68. CrossRef
Redox-Sensitive MarR Homologue BifR from Burkholderia thailandensis Regulates Biofilm Formation
Ashish Gupta, Stanley M. Fuentes, Anne Grove
Biochemistry.2017; 56(17): 2315. CrossRef
Exploring the potential of curcumin for control of N-acyl homoserine lactone-mediated biofouling in membrane bioreactors for wastewater treatment
Harshad Lade, Won Jung Song, Young Jae Yu, Jun Hee Ryu, G. Arthanareeswaran, Ji Hyang Kweon
RSC Advances.2017; 7(27): 16392. CrossRef
Quorum Sensing Down-Regulation Counteracts the Negative Impact of Pseudomonas aeruginosa on CFTR Channel Expression, Function and Rescue in Human Airway Epithelial Cells
Émilie Maillé, Manon Ruffin, Damien Adam, Hatem Messaoud, Shantelle L. Lafayette, Geoffrey McKay, Dao Nguyen, Emmanuelle Brochiero
Frontiers in Cellular and Infection Microbiology.2017;[Epub] CrossRef
Quorum‐sensing inhibition abrogates the deleterious impact of Pseudomonas aeruginosa on airway epithelial repair
Manon Ruffin, Claudia Bilodeau, Emilie Maillé, Shantelle L. LaFayette, Geoffrey A. McKay, Nguyen Thu Ngan Trinh, Trevor Beaudoin, Martin‐Yvon Desrosiers, Simon Rousseau, Dao Nguyen, Emmanuelle Brochiero
The FASEB Journal.2016; 30(9): 3011. CrossRef
Plant Natural Products Targeting Bacterial Virulence Factors
Laura Nunes Silva, Karine Rigon Zimmer, Alexandre José Macedo, Danielle Silva Trentin
Chemical Reviews.2016; 116(16): 9162. CrossRef
An Unexpected 2,3-Dihydrofuran Derivative Ring Opening Initiated by Electrophilic Bromination: Scope and Mechanistic Study
Yi Zhao, Ying-Chieh Wong, Ying-Yeung Yeung
The Journal of Organic Chemistry.2015; 80(1): 453. CrossRef
A new class of bacterial quorum sensing antagonists: glycomonoterpenols synthesized using linalool and alpha terpineol
Ruchira Mukherji, Asmita Prabhune
World Journal of Microbiology and Biotechnology.2015; 31(6): 841. CrossRef
Draft Genome Sequence of Cellulophaga sp. E6, a Marine Algal Epibiont That Produces a Quorum-Sensing Inhibitory Compound Active against Pseudomonas aeruginosa
J. E. Lafleur, S. K. Costa, A. S. Bitzer, M. W. Silby
Genome Announcements.2015;[Epub] CrossRef
Chronic Wound Biofilms: Pathogenesis and Potential Therapies
Allie Clinton, Tammy Carter
Laboratory Medicine.2015; 46(4): 277. CrossRef

Research Support, U.S. Gov't, Non-P.H.S.

NOTE] The Helicobacter pylori Ferric Uptake Regulator (Fur) Is Essential for Growth Under Sodium Chloride Stress: Hanan Gancz , D. Scott Merrell; J. Microbiol. 2011;49(2):294-298. Published online May 3, 2011; DOI: https://doi.org/10.1007/s12275-011-0396-7

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Abstract: Epidemiological data and animal models indicate that Helicobacter pylori and dietary NaCl have a synergistic ill effect on gastric maladies. Here we show that the Ferric Uptake Regulator (Fur), which is a crucial regulatory factor required for H. pylori colonization, is essential for growth in the presence of high NaCl concentrations. Moreover, we demonstrate that the transcriptional response induced by sodium chloride stress exhibits similarities to that seen under iron depletion.

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

Metagenomic Assessment of a Sulfur-Oxidizing Enrichment Culture Derived from Marine Sediment: Man-Young Jung , VinhHoa Pham , Soo-Je Park , So-Jeong Kim , Jong-Chan Chae , Yul Roh , Sung-Keun Rhee; J. Microbiol. 2010;48(6):739-747. Published online January 9, 2011; DOI: https://doi.org/10.1007/s12275-010-0257-9

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Abstract: The biological oxidation of reduced sulfur compounds is a critically important process in global sulfur biogeochemistry. In this study, we enriched from marine sediments under denitrifying conditions, chemolithotrophic sulfur oxidizers that could oxidize a variety of reduced sulfur compounds: thiosulfate, tetrathionate, sulfide, and polysulfide. Two major phylotypes of 16S rRNA gene (>99% identity in each phylotype) were detected in this enrichment culture. In order to characterize sulfide oxidation, we sequenced and characterized one fosmid clone (43.6 kb) containing the group I sulfide-quinone reductase (sqr) gene. Interestingly, four putative rhodanese genes were found in this clone. Furthermore, comparative alignment with the closest genome of Thiomicrospira crunogena XCL2 revealed that three homologous genes were located within the vicinity of the sqr gene. Fosmid clones harboring carbon fixation (cbbL and cbbM) and denitrification (narG) genes were screened, and the phylogeny of the functional genes was analyzed. Along with the comparison between the sqr-containing fosmid clones and the relevant gamma-proteobacteria, our phylogenetic study based on the 16S rRNA gene and carbon fixation genes suggest the prevalence of chemolithotrophic gamma-proteobacteria in the denitrifying cultures. The findings of this study imply that a combination of cultivation and metagenomic approaches might provide us with a glimpse into the characteristics of sulfur oxidizers in marine sediments.

Bacillus megaterium Strain XTBG34 Promotes Plant Growth by Producing 2-Pentylfuran: Changsong Zou , Zhifang Li , Diqiu Yu; J. Microbiol. 2010;48(4):460-466. Published online August 20, 2010; DOI: https://doi.org/10.1007/s12275-010-0068-z

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Abstract: Several chemical changes in soil are associated with plant growth-promoting rhizobacteria. An endosporeforming bacterium, strain XTBG34, was isolated from a Xishuangbanna Tropical Botanical Garden soil sample and identified as Bacillus megaterium. The strain’s volatiles had remarkable plant growth promotion activity in Arabidopsis thaliana plants; after 15 days treatment, the fresh weight of plants inoculated with XTBG34 was almost 2-fold compared with those inoculated with DH5α. Head space volatile compounds produced by XTBG34, trapped with headspace solid phase microextraction and identified by gas chromatography–mass spectrometry, included aldehydes, alkanes, ketones and aroma components. Of the 11 compounds assayed for plant growth promotion activity in divided Petri plates, only 2-pentylfuran increased plant growth. We have therefore identified a new plant growth promotion volatile of B. megaterium XTBG34, which deserves further study in the mechanisms of interaction between plant growth-promoting rhizobacteria and plants.

Experimental and Computational Characterization of the Ferric Uptake Regulator from Aliivibrio salmonicida (Vibrio salmonicida): Hege Lynum Pedersen , Rafi Ahmad , Ellen Kristin Riise , Hanna-Kirsti Schrøder Leiros , Stefan Hauglid , Sigrun Espelid , Bjørn Olav Brandsdal , Ingar Leiros , Nils-Peder Willassen , Peik Haugen; J. Microbiol. 2010;48(2):174-183. Published online May 1, 2010; DOI: https://doi.org/10.1007/s12275-010-9199-5

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Abstract: The Ferric uptake regulator (Fur) is a global transcription factor that affects expression of bacterial genes in an iron-dependent fashion. Although the Fur protein and its iron-responsive regulon are well studied, there are still important questions that remain to be answered. For example, the consensus Fur binding site also known as the “Fur box” is under debate, and it is still unclear which Fur residues directly interact with the DNA. Our long-term goal is to dissect the biological roles of Fur in the development of the disease cold-water vibriosis, which is caused by the psychrophilic bacteria Aliivibrio salmonicida (also known as Vibrio salmonicida). Here, we have used experimental and computational methods to characterise the Fur protein from A. salmonicida (AS-Fur). Electrophoretic mobility shift assays show that AS-Fur binds to the recently proposed vibrio Fur box consensus in addition to nine promoter regions that contain Fur boxes. Binding appears to be dependent on the number of Fur boxes, and the predicted “strength” of Fur boxes. Finally, structure modeling and molecular dynamics simulations provide new insights into potential AS-Fur–DNA interactions.

Microbial Diversity of a Sulfide Black Smoker in Main Endeavour Hydrothermal Vent Field, Juan de Fuca Ridge: Huaiyang Zhou , Jiangtao Li , Xiaotong Peng , Jun Meng , Fengping Wang , Yuncan Ai; J. Microbiol. 2009;47(3):235-247. Published online June 26, 2009; DOI: https://doi.org/10.1007/s12275-008-0311-z

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Abstract: Submarine hydrothermal vents are among the least-understood habitats on Earth but have been the intense focus of research in the past 30 years. An active hydrothermal sulfide chimney collected from the Dudley site in the Main Endeavour vent Field (MEF) of Juan de Fuca Ridge was investigated using mineralogical and molecular approaches. Mineral analysis indicated that the chimney was composed mainly of Fe-, Zn- and Cu-rich sulfides. According to phylogenetic analysis, within the Crenarchaeota, clones of the order Desulfurococcales predominated, comprising nearly 50% of archaeal clones. Euryarchaeota were composed mainly of clones belonging to Thermococcales and deep-sea hydrothermal vent Euryarchaeota (DHVE), each of which accounted for about 20% of all clones. Thermophilic or hyperthermophilic physiologies were common to the predominant archaeal groups. More than half of bacterial clones belonged to ε-Proteobacteria, which confirmed their prevalence in hydrothermal vent environments. Clones of Proteobacteria (γ-, δ-, β-), Cytophaga-Flavobacterium-Bacteroides (CFB) and Deinococcus-Thermus occurred as well. It was remarkable that methanogens and methanotrophs were not detected in our 16S rRNA gene library. Our results indicated that sulfur-related metabolism, which included sulfur-reducing activity carried out by thermophilic archaea and sulfur-oxidizing by mesophilic bacteria, was common and crucial to the vent ecosystem in Dudley hydrothermal site.

Enhancement of Growth and Yield of Tomato by Rhodopseudomonas sp. under Greenhouse Conditions: Kang-Hyeong Lee , Rae-Hyun Koh , Hong-Gyu Song; J. Microbiol. 2008;46(6):641-646. Published online December 24, 2008; DOI: https://doi.org/10.1007/s12275-008-0159-2

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Abstract: A greenhouse test was carried out to examine the effects on tomato growth of application of purple nonsulfur bacterium Rhodopseudomonas sp. which had enhanced germination and growth of tomato seed under axenic conditions. The shoot length of tomato plant inoculated by Rhodopseudomonas sp. KL9 increased by 34.6% compared to that of control in 8 weeks of cultivation. During the same period, this strain increased 120.6 and 78.6% of dry weight of shoot and root of tomato plants, respectively. The formation ratio of tomato fruit from flower was also raised by inoculation of KL9. In addition, Rhodopseudomonas sp. KL9 treatment enhanced the fresh weight and lycopene content in the harvested tomato fruits by 98.3 and 48.3%, respectively compared to those of the uninoculated control. When the effect on the indigenous bacterial community and fate of the inoculated Rhodopseudomonas sp. KL9 were monitored by denaturing gradient gel electrophoresis analysis, its application did not affect the native bacterial community in tomato rhizosphere soil, but should be repeated to maintain its population size. This bacterial capability may be applied as an environment-friendly biofertilizer to cultivation of high quality tomato and other crops including lycopene-containing vegetables and fruits.

NOTE] Molecular Analysis of the fur (ferric uptake regulator) Gene of a Pathogenic Edwardsiella tarda Strain: Fang Wang , Shuang Cheng , Kun Sun , Li Sun; J. Microbiol. 2008;46(3):350-355. Published online July 5, 2008; DOI: https://doi.org/10.1007/s12275-008-0038-x

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Abstract: The gene encoding the Edwardsiella tarda ferric uptake regulator (FurEt) was cloned from a pathogenic E. tarda strain isolated from diseased fish. FurEt shares 90% overall sequence identity with the Escherichia coli Fur (FurEc) and was able to complement the mutant phenotype of a furEc-defective E. coli strain. Mutational analysis indicated that C92S and C95S mutations inactivated FurEt whereas E112K mutation resulted in a superactive FurEt variant. FurEt negatively regulated its own expression; interruption of this regulation impaired bacterial growth, altered the production of certain outer membrane proteins, and attenuated bacterial virulence.

Effect of fur on pyrC Gene Expression: Sangho Chai , Chang Kyu Song , Seong Kwun Kim , Jun Ho Park , Sechan Wee; J. Microbiol. 2007;45(6):583-589.; DOI: https://doi.org/2604 [pii]

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Abstract: The promoter region of pyrC (dihydroorotase) gene of Escherichia coli was shown to have Fur protein binding properties by gel retardation assay. In vivo regulation of the pyrC expression was studied by measuring dihydroorotase activity and beta-galactosidase level in the fur+ and fur- genetic background. The expression of chromosomal dihydroorotase activity and beta-galactosidase activity of pyrC-lacZ fusion plasmid was repressed to about 30% and 17%, respectively in the fur+ strain compared to those in the fur- strain. Divalent ions such as Fe2+ and Zn2+ were not required for the repression. PyrC expression was also reduced to one half by 1 mM uracil. The effect of uracil was independent on the fur gene.

Isolation, characterization, and phylogenetic position of a new sulfur-oxidizing bacterium: Chang, So Youn , Yoon, Joon Sik , Shin, Yong Kook , Park, Yong Ha , Park, Jin Yeol , Yang, Song Suk , Koh, Moon Joo , Yoon, Seong Myeong , Lee, Jung Sup , Lee, In Hwa , Kim, Si Wouk; J. Microbiol. 1997;35(3):165-171.

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Abstract: A sulfer-oxidizing bacterium was isolated from mine wastewater and characterized. The isolate was gram-negative, rod (0.2 × 1.2-1.5㎛), nonmotiloe, catalase positive, and oxidase positive. The optimal pH and temperature for growth were 7.0 and 30℃, respectively. The optimum thiosulfate concentration was 70 mM and the maximum growth rate was 0.081 hr. The major ubiquinone contained in the isolate was Q-8. The cellular fatty acid composition was C_16:0, C_18:1, C_17cyc, and C_19cyc as nonpolar fatty acids, and 3-OH C10 : 0 and 3-OH C_12:0 as hydroxylated fatty acids. The isolate was a facultative chemolithoautotroph which can grow autotrophically on sodium thiosulfate and sodium sulfide and which can grow heterotrophically on yeast extract. It can also grow mixotrophically on sodium thiosulfate and yeast extract. Comparison of the 16S rRNA gene sequence of the isolate with that of Thiobacillus species and Paracoccus thiocyanatus revealed that it is closely related to T. caldus which belongs to the β-subclass of the class Proteobacteria. However, the isolated could not grow at extremely low pH (pH 1-3.5). On the basis of the phenotypic, chemotaxonomic and phylogenetic data, the isolate was tentatively named Thiobacillus sp. strain C.

Biodegradation of Dibenzo-p-dioxin and Dibenzofuran by bacteria: Jean Armengaud , Kenneth N. Timmis; J. Microbiol. 1997;35(4):241-252.

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Abstract: Polychlorodibenzofurans and polychlorodibenzo-pdioxins are among the most toxic xenobiotics released into the biosphere and the cause of significant public concern because of their apparent ubiquityalbeit at low levels- in food and environment. Several bacteria able to degrade nonchlorinated dioxin and dibenzofuran and in some cases to attack chlorinated analogues have recently been isolated. This opens up the possibility that bioremediation processes may ultimately be developed to eliminate these toxic compounds from contaminated sites. In this review we summarize current knowledge on the genetics and biochemistry of dioxin and dibenzofruan degradation by Sphingomonas sp. RW1, a gram-negative bacterium, and highlight the unusual nature of the genetic organization of these pathways.

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).

Association of a Common Reductase with Multiple Aromatic Terminal Dioxygenases in Sphingomonas yanoikuyae Strain B1: Mihyun Bae , Eungbin Kim; J. Microbiol. 2000;38(1):40-43.

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Abstract: The aromatic dioxygenase system in Sphingomonas yanoikuyae strain B1 consists of three components, an oxygenase, a ferredoxin, and a reductase. The insertional knockout of the bphA4 gene encoding a reductase and subsequent complementation experiments showed that the reductase encoded by bphA4 in S. yanoikuyae strain B1 is associated with multiple dioxygenase components including that of toluate dioxygenase (XylXY).

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