Journal of Microbiology

Volume 52(6); June 2014

Review

MINIREVIEW] The Role of MicroRNAs in Hepatitis C Virus Replication and Related Liver Diseases: Chang Ho Lee , Ji Hyun Kim , Seong-Wook Lee; J. Microbiol. 2014;52(6):445-451. Published online May 29, 2014; DOI: https://doi.org/10.1007/s12275-014-4267-x

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39 Citations

Abstract: Hepatitis C virus (HCV) infection is a worldwide health problem and is one of the main causes of chronic hepatitis, liver cirrhosis, and hepatocellular carcinoma (HCC). However, only limited therapeutic options and no vaccines are currently available against HCV infection. Recent studies of microRNAs (miRNAs), which are able to regulate HCV replication and its related liver diseases by directly interacting with the HCV genome or indirectly controlling virus-associated host pathways, have broadened our understanding of the HCV life cycle. HCV utilizes host cellular miRNAs and modulates expression of miRNAs in infected hepatocytes for its infection and propagation. Moreover, such miRNAs directly or indirectly alter HCV replication efficiency and induce liver diseases including liver fibrosis, cirrhosis, or HCC. Representatively, miR-122 directly modulates the HCV life cycle by increasing HCV translation and genomic RNA stability. Recently, a phase IIa clinical trial with miravirsen, an LNA form of antimiR-122 oligonucleotides, showed significant reduction in serum HCV levels in patients chronically infected with HCV with no detectible evidence of resistance. In addition to miR-122, other miRNAs involved in the regulation of HCV propagation could be targeted in strategies to modulate HCV replication and pathogenesis. In this review, we summarize the features of miRNAs critical for HCV replication and HCV-mediated liver abnormalities and briefly discuss their potential application as therapeutic reagents for the treatment of HCV infection and its related diseases.

Journal Article

Comparative Study of the marR Genes within the Family Enterobacteriaceae: Dan Wang , Changjiang Guo , Longjiang Gu , Xiaohui Zhang; J. Microbiol. 2014;52(6):452-459. Published online April 11, 2014; DOI: https://doi.org/10.1007/s12275-014-3586-2

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8 Citations

Abstract: marR genes are members of an ancient family originally identified in Escherichia coli. This family is widely distributed in archaea and bacteria. Homologues of this family have a conserved winged helix fold. MarR proteins are involved in non-specific resistance systems conferring resistance to multiple antibiotics. Extensive studies have shown the importance of MarR proteins in physiology and pathogenicity in Enterobacteria, but little is known about their origin or evolution. In this study, all the marR genes in 43 enterobacterial genomes representing 14 genera were identified, and the phylogenetic relationships and genetic parameters were analyzed. Several major findings were made. Three conserved marR genes originated earlier than Enterobacteriaceae and a geneloss event was found to have taken place in Yersinia pestis Antiqua. Three functional genes, rovA, hor, and slyA, were found to be clear orthologs among Enterobacteriaceae. The copy number of marR genes in Enterobacteriaceae was found to vary from 2 to 11. These marR genes exhibited a faster rate of nucleotide substitution than housekeeping genes did. Specifically, the regions of marR domain were found to be subject to strong purifying selection. The phylogenetic relationship and genetic parameter analyses were consistent with conservation and specificity of marR genes. These dual characters helped MarR to maintain a conserved binding motif and variable C-terminus, which are important to adaptive responses to a number of external stimuli in Enterobacteriaceae.

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

Paenibacillus cucumis sp. nov. Isolated from Greenhouse Soil: Jae-Hyung Ahn , Byoung-chan Kim , Byung-Yong Kim , Soo-Jin Kim , Jaekyeong Song , Soon-Wo Kwon , Hang-Yeon Weon; J. Microbiol. 2014;52(6):460-464. Published online May 29, 2014; DOI: https://doi.org/10.1007/s12275-014-4071-7

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Abstract: Strain CO 4-7T was isolated from greenhouse soil used for cultivation of cucumbers in Korea. The 16S rRNA gene sequence of strain CO 4-7T showed the highest sequence similarity with Paenibacillus contaminans CKOBP-6T (94.2%) among the type strains. Strain CO 4-7T was a strictly aerobic, Gram-staining-positive, endospore-forming, and motile rodshaped bacterium. Strain CO 4-7T grew at 10–45°C (optimum, 30°C), at pH 6.0–7.5 (optimum, pH 6.5) and in the presence of 0–5% NaCl (optimum, 0.5%). The DNA G+C content of strain CO 4-7T was 48.5 mol%. It contained MK-7 as the major isoprenoid quinone and anteiso-C15:0 (51.8%), C16:0 (12.7%), and iso-C16:0 (8.6%) as the major fatty acids. The cell wall contained meso-diaminopimelic acid. Based on evidence from our polyphasic taxonomic study, it was concluded that strain CO 4-7T should be classified as a novel species of the genus Paenibacillus, for which, the name Paenibacillus cucumis sp. nov. is proposed. The type strain is CO 4-7T (=KACC 17444T=JCM 19515T).

Identifying Airborne Fungi in Seoul, Korea Using Metagenomics: Seung-Yoon Oh , Jonathan J. Fong , Myung Soo Park , Limseok Chang , Young Woon Lim; J. Microbiol. 2014;52(6):465-472. Published online April 11, 2014; DOI: https://doi.org/10.1007/s12275-014-3550-1

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46 Citations

Abstract: Fungal spores are widespread and common in the atmosphere. In this study, we use a metagenomic approach to study the fungal diversity in six total air samples collected from April to May 2012 in Seoul, Korea. This springtime period is important in Korea because of the peak in fungal spore concentration and Asian dust storms, although the year of this study (2012) was unique in that were no major Asian dust events. Clustering sequences for operational taxonomic unit (OTU) identification recovered 1,266 unique OTUs in the combined dataset, with between 223-396 OTUs present in individual samples. OTUs from three fungal phyla were identified. For Ascomycota, Davidiella (anamorph: Cladosporium) was the most common genus in all samples, often accounting for more than 50% of all sequences in a sample. Other common Ascomycota genera identified were Alternaria, Didymella, Khuskia, Geosmitha, Penicillium, and Aspergillus. While several Basidiomycota genera were observed, Chytridiomycota OTUs were only present in one sample. Consistency was observed within sampling days, but there was a large shift in species composition from Ascomycota dominant to Basidiomycota dominant in the middle of the sampling period. This marked change may have been caused by meteorological events. A potential set of 40 allergyinducing genera were identified, accounting for a large proportion of the diversity present (22.5–77.2%). Our study identifies high fungal diversity and potentially high levels of fungal allergens in springtime air of Korea, and provides a good baseline for future comparisons with Asian dust storms.

Changes in Gene Expression of Actinobacillus pleuropneumoniae in Response to Anaerobic Stress Reveal Induction of Central Metabolism and Biofilm Formation: Lu Li , Jiawen Zhu , Kui Yang , Zhuofei Xu , Ziduo Liu , Rui Zhou; J. Microbiol. 2014;52(6):473-481. Published online April 11, 2014; DOI: https://doi.org/10.1007/s12275-014-3456-y

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16 Citations

Abstract: Actinobacillus pleuropneumoniae is an important porcine respiratory pathogen causing great economic losses in the pig industry worldwide. Oxygen deprivation is a stress that A. pleuropneumoniae will encounter during both early infection and the later, persistent stage. To understand modulation of A. pleuropneumoniae gene expression in response to the stress caused by anaerobic conditions, gene expression profiles under anaerobic and aerobic conditions were compared in this study. The microarray results showed that 631 genes (27.7% of the total ORFs) were differentially expressed in anaerobic conditions. Many genes encoding proteins involved in glycolysis, carbon source uptake systems, pyruvate metabolism, fermentation and the electron respiration transport chain were up-regulated. These changes led to an increased amount of pyruvate, lactate, ethanol and acetate in the bacterial cells as confirmed by metabolite detection. Genes encoding proteins involved in cell surface structures, especially biofilm formation, peptidoglycan biosynthesis and lipopolysaccharide biosynthesis were up-regulated as well. Biofilm formation was significantly enhanced under anaerobic conditions. These results indicate that induction of central metabolism is important for basic survival of A. pleuropneumoniae after a shift to an anaerobic environment. Enhanced biofilm formation may contribute to the persistence of this pathogen in the damaged anaerobic host tissue and also in the early colonization stage. These discoveries give new insights into adaptation mechanisms of A. pleuropneumoniae in response to environmental stress.

Prediction of Bacterial microRNAs and Possible Targets in Human Cell Transcriptome: Amir Shmaryahu , Margarita Carrasco , Pablo D.T. Valenzuela; J. Microbiol. 2014;52(6):482-489. Published online May 29, 2014; DOI: https://doi.org/10.1007/s12275-014-3658-3

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22 Citations

Abstract: Recent studies have examined gene transfer from bacteria to humans that would result in vertical inheritance. Bacterial DNA appears to integrate into the human somatic genome through an RNA intermediate, and such integrations are detected more frequently in tumors than normal samples and in RNA than DNA samples. Also, vertebrate viruses encode products that interfere with the RNA silencing machinery, suggesting that RNA silencing may indeed be important for antiviral responses in vertebrates. RNA silencing in response to virus infection could be due to microRNAs encoded by either the virus or the host. We hypothesized that bacterial expression of RNA molecules with secondary structures is potentially able to generate miRNA molecules that can interact with the human host mRNA during bacterial infection. To test this hypothesis, we developed a pipelinebased bioinformatics approach to identify putative micro-RNAs derived from bacterial RNAs that may have the potential to regulate gene expression of the human host cell. Our results suggest that 68 bacterial RNAs predicted from 37 different bacterial genomes have predicted secondary structures potentially able to generate putative microRNAs that may interact with messenger RNAs of genes involved in 47 different human diseases. As an example, we examined the effect of transfecting three putative microRNAs into human embryonic kidney 293 (HEK293) cells. The results show that the bacterially derived microRNA sequence can significantly regulate the expression of the respective target human gene. We suggest that the study of these predicted microRNAs may yield important clues as to how the human host cell processes involved in human diseases like cancer, diabetes, rheumatoid arthritis, and others may respond to a particular bacterial environment.

X-ray Structure of Prephenate Dehydratase from Streptococcus mutans: Min Hyung Shin , Hyung-Keun Ku , Jin Sue Song , Saehae Choi , Se Young Son , Hee-Dai Kim , Sook-Kyung Kim , Il Yeong Park , Soo Jae Lee; J. Microbiol. 2014;52(6):490-495. Published online March 7, 2014; DOI: https://doi.org/10.1007/s12275-014-3645-8

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Abstract: Prephenate dehydratase is a key enzyme of the biosynthesis of L-phenylalanine in the organisms that utilize shikimate pathway. Since this enzymatic pathway does not exist in mammals, prephenate dehydratase can provide a new drug targets for antibiotics or herbicide. Prephenate dehydratase is an allosteric enzyme regulated by its end product. The enzyme composed of two domains, catalytic PDT domain located near the N-terminal and regulatory ACT domain located near the C-terminal. The allosteric enzyme is suggested to have two different conformations. When the regulatory molecule, phenylalanine, is not bound to its ACT domain, the catalytic site of PDT domain maintain open (active) state conformation as Sa-PDT structure. And the open state of its catalytic site become closed (allosterically inhibited) state if the regulatory molecule is bound to its ACT domain as Ct-PDT structure. However, the X-ray structure of prephenate dehydratase from Streptococcus mutans (Sm-PDT) shows that the catalytic site of Sm-PDT has closed state conformation without phenylalanine molecule bound to its regulatory site. The structure suggests a possibility that the binding of phenylalanine in its regulatory site may not be the only prerequisite for the closed state conformation of Sm-PDT.

Diversity of Extended-Spectrum and Plasmid-Mediated AmpC β-Lactamases in Enterobacteriaceae Isolates from Portuguese Health Care Facilities: Daniela Jones-Dias , Vera Manageiro , Eugénia Ferreira , Deolinda Louro , Antibiotic Resistance Surveillance Program Program , Manuela Caniça; J. Microbiol. 2014;52(6):496-503. Published online May 29, 2014; DOI: https://doi.org/10.1007/s12275-014-3420-x

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20 Citations

Abstract: A group of 124 Enterobacteriaceae isolates resistant to third generation cephalosporins, and collected in distinct health care facilities of different Portuguese regions was analysed. The great majority of the isolates were also resistant to fourth generation cephalosporins (83.9%), monobactam (96%), amoxicillin plus clavulanic acid (85.5%), and piperacillin plus tazobactam (66.9%). Overall, 84.7% (105/124) were multidrug resistant. Molecular methods enabled us to identify 86.3% (107/124) extended-spectrum β-lactamases (ESBL) producers, revealing a diversity of class A β-lactamases from different families, like TEM (TEM-1, TEM-10, TEM-24, and TEM-52), SHV (SHV-1, SHV-12, and SHV-28), CTX-M (CTX-M-1, CTX-M-9, CTX-M-14, CTX-M-15, and CTXM-32), and GES (GES-1). We have also detected class C enzymes like plasmid-mediated AmpC β-lactamases (PMAβs, DHA-1, and CMY-2) and chromosomal AmpCs in Enterobacter and Citrobacter spp. The PMAβ genetic context mapping suggests association with mobile elements, plasmid importation and the potential emergence of these β-lactamases. The most prevalent β-lactamase detected was CTX-M-15 (66.1%) and in 41.1% of the isolates it was associated with TEM-, OXA-type β-lactamases and Aac(6)’-Ib-cr, which might indicate that the respective genotype has settled in our country. Indeed, CTX-M-15 was distributed amongst distinct clinical settings of several health care facilities (93.5%) from various regions. We provide evidence of a concerning clinical situation that includes vast occurrence of ESBLs, the settling of CTX-M β-lactamases, and the report of plasmidic and chromosomal AmpC in Portugal.

Profiling of the Bacteria Responsible for Pyogenic Liver Abscess by 16S rRNA Gene Pyrosequencing: Yun Gyu Song , Sang Gun Shim , Kwang Min Kim , Dong-Hae Lee , Dae-Soo Kim , Sang-Haeng Choi , Jae-Young Song , Hyung-Lyun Kang , Seung-Chul Baik , Woo-Kon Lee , Myung-Je Cho , Kwang-Ho Rhee; J. Microbiol. 2014;52(6):504-509. Published online May 29, 2014; DOI: https://doi.org/10.1007/s12275-014-4241-7

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21 Citations

Abstract: Pyogenic liver abscess (PLA) is a severe disease with considerable mortality and is often polymicrobial. Understanding the pathogens that cause PLA is the basis for PLA treatment. Here, we profiled the bacterial composition in PLA fluid by pyrosequencing the 16S ribosomal RNA (rRNA) gene based on next-generation sequencing (NGS) technology to identify etiological agents of PLA and to provide information of their 16S rRNA sequences for application to DNA-based techniques in the hospital. Twenty patients with PLA who underwent percutaneous catheter drainage, abscess culture, and blood culture for isolates were included. Genomic DNAs from abscess fluids were subjected to polymerase chain reaction and pyrosequencing of the 16S rRNA gene with a 454 GS Junior System. The abscess and blood cultures were positive in nine (45%) and four (20%) patients, respectively. Pyrosequencing of 16S rRNA gene showed that 90% of the PLA fluid samples contained single or multiple genera of known bacteria such as Klebsiella, Fusobacterium, Streptococcus, Bacteroides, Prevotella, Peptostreptococcus, unassigned Enterobacteriaceae, and Dialister. Klebsiella was predominantly found in the PLA fluid samples. All samples that carried unassigned bacteria had 26.8% reads on average. We demonstrated that the occurrence of PLA was associated with eight known bacterial genera as well as unassigned bacteria and that 16S rRNA gene sequencing was more useful than conventional culture methods for accurate identification of bacterial pathogens from PLA.

Altered mRNA Levels of MOV10, A3G, and IFN-α in Patients with Chronic Hepatitis B: Zhi-Wei Song , Yan-Xiu Ma , Li-Juan Fu , Bao-qing Fu , Xu Teng , Si-Jia Chen , Wei-Zhen Xu , Hong-Xi Gu; J. Microbiol. 2014;52(6):510-514. Published online May 29, 2014; DOI: https://doi.org/10.1007/s12275-014-3467-8

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Abstract: To explore the relationship of the MOV10, A3G, and IFN-α mRNA levels with chronic hepatitis B virus (HBV) infection, Blood samples from 96 patients with chronic hepatitis B (CHB) and 21 healthy individuals as control were collected. HBV DNA load and aminotransferase in the serum were tested using real time PCR and velocity methods, respectively. The MOV10, A3G, and IFN-α mRNA levels in the peripheral blood mononuclear cells (PBMC) were examined through qRT-PCR. The MOV10, A3G, and IFN-α mRNA levels in CHB group was significantly lower than those in the control group (P<0.01, P<0.05, P<0.01, respectively). The A3G mRNA level in the high-HBV DNA load group was lower than that in the low-HBV DNA load group (P<0.05). However, no statistical difference was found in the MOV10 and IFN-α mRNA levels between the two HBV DNA load groups. Furthermore, the MOV10 mRNA level showed positive correlation with IFN-α in the control group. These results indicated that the expression of the innate immune factors MOV10, A3G, and IFN-α is affected by chronic HBV infection.

Superinfection Exclusion Reveals Heteroimmunity between Pseudomonas aeruginosa Temperate Phages: In-Young Chung , Hee-Won Bae , Hye-Jung Jang , Bi-o Kim , You-Hee Cho; J. Microbiol. 2014;52(6):515-520. Published online May 29, 2014; DOI: https://doi.org/10.1007/s12275-014-4012-5

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Abstract: Temperate siphophages (MP29, MP42, and MP48) were isolated from the culture supernatant of clinical Pseudomonas aeruginosa isolates. The complete nucleotide sequences and annotation of the phage genomes revealed the overall synteny to the known temperate P. aeruginosa phages such as MP22, D3112, and DMS3. Genome-level sequence analysis showed the conservation of both ends of the linear genome and the divergence at the previously identified dissimilarity regions (R1 to R9). Protein sequence alignment of the c repressor (ORF1) of each phage enabled us to divide the six phages into two groups: D3112 group (D3112, MP29, MP42, and MP48) and MP22 group (MP22 and DMS3). Superinfection exclusion was observed between the phages belonging to the same group, which was mediated by the specific interaction between the c repressor and the cognate operator. Based on these, we suggest that the temperate siphophages prevalent in the clinical strains of P. aeruginosa represent at least two distinct heteroimmunity groups.

Antiviral Activity of 3,4'-Dihydroxyflavone on Influenza A Virus: Mohammed Kawser Hossain , Hye Yeon Choi , Jae-Seon Hwang , Ahmed Abdal Dayem , Jung-Hyun Kim , Young Bong Kim , Haryoung Poo , Ssang-Goo Cho; J. Microbiol. 2014;52(6):521-526. Published online May 29, 2014; DOI: https://doi.org/10.1007/s12275-014-4212-z

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Abstract: Influenza virus infection causes thousands of deaths and millions of hospitalizations worldwide every year and the emergence of resistance to anti-influenza drugs has prompted scientists to seek new natural antiviral materials. In this study, we screened 13 different flavonoids from various flavonoid groups to identify the most potent antiviral flavonoid against human influenza A/PR/8/34 (H1N1). The 3-hydroxyl group flavonoids, including 3,2'-dihydroxyflavone (3,2'-DHF) and 3,4'-dihydroxyflavone (3,4'-DHF), showed potent anti-influenza activity. They inhibited viral neuraminidase activity and viral adsorption onto cells. To confirm the anti-influenza activity of these flavonoids, we used an in vivo mouse model. In mice infected with human influenza, oral administration of 3,4'-DHF significantly decreased virus titers and pathological changes in the lung and reduced body weight loss and death. Our data suggest that 3-hydroxyl group flavonoids, particularly 3,4'-DHF, have potent antiviral activity against human influenza A/PR/8/34 (H1N1) in vitro and in vivo. Further clinical studies are needed to investigate the therapeutic and prophylactic potential of the 3-hydroxyl group flavonoids in treating influenza pandemics.

NOTE] Diaminobutyricibacter tongyongensis gen. nov., sp. nov. and Homoserinibacter gongjuensis gen. nov., sp. nov. Belong to the Family Microbacteriaceae: Soo-Jin Kim , Jae-Hyung Ahn , Hang-Yeon Weon , Moriyuki Hamada , Ken-ichiro Suzuki , Soon-Wo Kwon; J. Microbiol. 2014;52(6):527-533. Published online February 17, 2014; DOI: https://doi.org/10.1007/s12275-014-3278-y

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Abstract: Two bacterial strains, KIS66-7T and 5GH26-15T, were isolated from soil samples collected in the South Korean cities of Tongyong and Gongju, respectively. Both strains were aerobic, Gram-stain-positive, mesophilic, flagellated, and rodshaped. A phylogenetic analysis revealed that both strains belonged to the family Microbacteriaceae of the phylum Actinobacteria. The 16S rRNA gene sequence of strain KIS66-7T had the highest similarities with those of Labedella gwakjiensis KSW2-17T (97.3%), Cryobacterium psychrophilum DSM 4854T (97.2%), Leifsonia lichenia 2SbT (97.2%), Leifsonia naganoensis JCM 10592T (97.0%), and Cryobacterium mesophilum MSL-15T (97.0%). Strain 5GH26-15T showed the highest sequence similarities with Leifsonia psychrotolerans LI1T (97.4%) and Schumannella luteola KHIAT (97.1%). The 16S rRNA gene sequence from KIS66-7T exhibited 96.4% similarity with that from 5GH26-15T. Strain KIS66-7T contained a B2γ type peptidoglycan structure with D-DAB as the diamino acid; MK-13, MK-12, and MK-14 as the respiratory quinones; ai-C15:0, ai-C17:0, and i-C16:0 as the major cellular fatty acids; and diphosphatidylglycerol, phatidylglycerol, and glycolipids as the predominant polar lipids. Strain 5GH26-15T had a B2β type peptidoglycan structure with D-DAB as the diamino acid; MK-14 and MK-13 as the respiratory quinones; ai-C15:0, i-C16:0, and ai-C17:0 as the major cellular fatty acids; and diphosphatidylglycerol, phatidylglycerol, and glycolipids as the predominant polar lipids. Both strains had low DNA-DNA hybridization values (<40%) with closely related taxa. Based on our polyphasic taxonomic characterization, we propose that strains KIS66-7T and 5GH26-15T represent novel genera and species, for which we propose the names Diaminobutyricibacter tongyongensis gen. nov., sp. nov. (type strain KIS66-7T =KACC 15515T =NBRC 108724T) and Homoserinibacter gongjuensis gen. nov., sp. nov. (type strain 5GH26-15T =KACC 15524T =NBRC 108755T) within the family Microbacteriaceae.

Author’s Correction] Development and Evaluation of Multiplex Real-time RT-PCR Assays for Seasonal, Pandemic A/H1pdm09 and Avian A/H5 Influenza Viruses Detection: Jang-Hoon Choi , Mi-Seon Kim , Joo-Yeon Lee , Nam-Joo Lee , Donghyok Kwon , Min Gu Kang , Chun Kang; J. Microbiol. 2014;52(6):534-534.; DOI: https://doi.org/10.1007/s12275-014-0699-6

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Abstract: In the article by Choi et al. published in Journal of Microbiology 2013; 51, 252-257. Table 1 on page 253 should be changed as below. (Please check attached file)

Erratum] Predictive Modelling of Lactobacillus casei KN291 Survival in Fermented Soy Beverage: Zieli&# , Koło&# , Goryl Antoni , Ilona Motyl; J. Microbiol. 2014;52(6):535-535.; DOI: https://doi.org/10.1007/s12275-014-0700-4

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Abstract: In the article by Dorota et al. published in Journal of Microbiology 2014; 52, 169-179. First three authors’ first name and last name has been changed. Corrected name is Dorota Zielinska, Danuta Kolozyn-Krajewska, Antoni Goryl.

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