Journal of Microbiology

Volume 49(6); December 2011

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

Cupriavidus and Burkholderia Species Associated with Agricultural Plants that Grow in Alkaline Soils: Paulina Estrada-de los Santos , Nora Belinda Vacaseydel-Aceves , Lourdes Martínez-Aguilar , María Antonia Cruz-Hernández , Alberto Mendoza-Herrera , Jesús Caballero-Mellado; J. Microbiol. 2011;49(6):867-876. Published online December 28, 2011; DOI: https://doi.org/10.1007/s12275-011-1127-9

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29 Citations

Abstract: The presence of Burkholderia, Cupriavidus, and Ralstonia species in northeastern Mexico was investigated. An analysis of the root surrounding soil from different agricultural plants led to the isolation of Burkholderia and Cupriavidus species but no Ralstonia strains. Most Cupriavidus species were unknown and grouped into two clusters according to ARDRA profiles. The 16S rRNA sequence analysis showed that the Cupriavidus isolates were highly related among them and with different Cupriavidus species with validated names. However, SDS-PAGE profiles were distinct among the different ARDRA profiles and to other Cupriavidus species examined, suggesting new species in the genus. This shows that Cupriavidus is more widely associated with plants than previously appreciated. The BCC isolate was 99% similar to B. cenocepacia by recA sequence analysis. Additionally, most Cupriavidus strains from the two largest groups grew on media containing up to 0.1 mg/ml of copper, 10.0 mg/ml arsenic and 1.0 mg/ml zinc. Burkholderia strains grew on media containing up to 10.0 mg/ml zinc, 5.0 mg/ml arsenic and 0.1 mg/ml copper.

Lactobacillus salivarius REN Counteracted Unfavorable 4-Nitroquinoline-1-Oxide-Induced Changes in Colonic Microflora of Rats: Ming Zhang , Xuewei Qiao , Liang Zhao , Lu Jiang , Fazheng Ren; J. Microbiol. 2011;49(6):877-883. Published online December 28, 2011; DOI: https://doi.org/10.1007/s12275-011-1137-7

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14 Citations

Abstract: Probiotics and carcinogens both have a significant effect on the microfloral composition of the human intestine. The objective of this study was to investigate the impact of an important carcinogen, 4-Nitroquinoline-1- Oxide on colonic microflora and the efficacy of the probiotic Lactobacillus salivarius REN as an agent of counteracting these effects. Using denaturing gradient gel electrophoresis (DGGE) combined with redundancy analysis, we demonstrated that both 4-Nitroquinoline-1-Oxide and L. salivarius REN significantly altered the bacterial communities of rat colons. A total of 27 bacterial strains were identified as being affected by treatment with 4-Nitroquinoline-1-Oxide or L. salivarius REN using a t-value biplot combined with band sequencing. 4-Nitroquinoline-1-Oxide treatment increased the abundance of two potential pathogens (one Helicobacter strain and one Desulfovibrio strain), as well as reducing the abundance of two potentially beneficial strains (one Ruminococcaceae strain and one Rumen bacteria). The Helicobacter strain was initally detected in carcinogen-treated rat intestinal microflora, but L. salivarius REN treatment effectively suppressed the growth of the Helicobacter strain. These results suggested that L. salivarius REN may be a potential probiotic, efficiently acting against the initial infection with, and the growth of pathogenic bacteria.

The Use of Pseudomonas fluorescens P13 to Control Sclerotinia Stem Rot (Sclerotinia sclerotiorum) of Oilseed Rape: Hui Li , Huaibo Li , Yan Bai , Jing Wang , Ming Nie , Bo Li , Ming Xiao; J. Microbiol. 2011;49(6):884-889. Published online December 28, 2011; DOI: https://doi.org/10.1007/s12275-011-1261-4

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28 Citations

Abstract: Sclerotinia stem rot (SSR) caused by the fungus Sclerotinia sclerotiorum has been an increasing threat to oilseed rape (Brassica napus L.) cultivation. Efficient and environment‐friendly treatments are much needed. Here we focus on microbial control. The Pseudomonas fluorescens P13 that was isolated from oilseed rape cultivation soil, proved to be a useful biocontrol strain for application. Morphology, physiological and biochemical tests and 16S rDNA analysis demonstrated that it was P. fluorescens P13 and that it had a broad antagonistic spectrum, significantly lessening the mycelial growth of S. sclerotiorum by 84.4% and suppressing sclerotial formation by 95‐100%. Scanning electron microscopy studies attested that P13 deformed S. sclerotiorum mycelia when they were cultured together. P13 did not produce chitinase but did produce hydrogen cyanide (HCN) which was likely one of the antagonistic mechanisms. The density of P13 remained at a high level (≥106 CFU/ml) during 5 weeks in the rhizosphere soil and roots. P13 reduced SSR severity at least by 59% in field studies and also promoted seedling growth (p<0.05) at the seedling stage. From these data, our work provided evidence that P13 could be a good alternative biological resource for biocontrol of S. sclerotiorum.

Complete Genome of Leptospirillum ferriphilum ML-04 Provides Insight into Its Physiology and Environmental Adaptation: Shuang Mi , Jian Song , Jianqun Lin , Yuanyuan Che , Huajun Zheng , Jianqiang Lin; J. Microbiol. 2011;49(6):890-901. Published online December 28, 2011; DOI: https://doi.org/10.1007/s12275-011-1099-9

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49 Citations

Abstract: Leptospirillum ferriphilum has been identified as the dominant, moderately thermophilic, bioleaching microorganism in bioleaching processes. It is an acidic and chemolithoautrophic bacterium that gains electrons from ferrous iron oxidation for energy production and cell growth. Genetic information about this microorganism has been limited until now, which has hindered its further exploration. In this study, the complete genome of L. ferripilum ML-04 is sequenced and annotated. The bacterium has a single circular chromosome of 2,406,157 bp containing 2,471 coding sequences (CDS), 2 rRNA operons, 48 tRNA genes, a large number of mobile genetic elements and 2 genomic islands. In silico analysis shows L. ferriphilum ML-04 fixes carbon through a reductive citric acid (rTCA) cycle, and obtains nitrogen through ammonium assimilation. The genes related to “cell envelope biogenesis, outer membrane” (6.9%) and “DNA replication, recombination and repair” (5.6%) are abundant, and a large number of genes related to heavy metal detoxification, oxidative and acidic stress defense, and signal transduction pathways were detected. The genomic plasticity, plentiful cell envelope components, inorganic element metabolic abilities and stress response mechanisms found the base for this organism’s survival in the bioleaching niche.

Characterization and Screening of Plant Probiotic Traits of Bacteria Isolated from Rice Seeds Cultivated in Argentina: Dante Ruiza , Betina Agaras , Patrice de Werrab , Luis G. Wall , Claudio Valverde; J. Microbiol. 2011;49(6):902-912. Published online December 28, 2011; DOI: https://doi.org/10.1007/s12275-011-1073-6

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61 Citations

Abstract: Many seeds carry endophytes, which ensure good chances of seedling colonization. In this work, we have studied the seed-borne bacterial flora of rice varieties cultivated in the northeast of Argentina. Surface-sterilized husked seeds of the rice cultivars CT6919, El Paso 144, CAMBA, and IRGA 417 contained an average of 5×106 CFU/g of mesophilic and copiotrophic bacteria. Microbiological, physiological, and molecular characterization of a set of 39 fast-growing isolates from the CT6919 seeds revealed an important diversity of seed-borne mesophiles and potential plant probiotic activities, including diazotrophy and antagonism of fungal pathogens. In fact, the seed-borne bacterial flora protected the rice seedlings against Curvularia sp. infection. The root colonization pattern of 2 Pantoea isolates from the seeds was studied by fluorescence microscopy of the inoculated axenic rice seedlings. Both isolates strongly colonized the site of emergence of the lateral roots and lenticels, which may represent the entry sites for endophytic spreading. These findings suggest that rice plants allow grain colonization by bacterial species that may act as natural biofertilizers and bioprotectives early from seed germination.

A Survey of the Geographic Distribution of Ophiocordyceps sinensis: Yi Li , Xiao-Liang Wang , Lei Jiao , Yi Jiang , Hui Li , Si-Ping Jiang , Ngarong Lhosumtseiring , Shen-Zhan Fu , Cai-Hong Dong , Yu Zhan , Yi-Jian Yao; J. Microbiol. 2011;49(6):913-919. Published online December 28, 2011; DOI: https://doi.org/10.1007/s12275-011-1193-z

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107 Citations

Abstract: Ophiocordyceps sinensis is one of the best known fungi in Traditional Chinese Medicine. Many efforts have been devoted to locating the production areas of this species resulting in various reports; however, its geographic distribution remains incompletely understood. Distribution of O. sinensis at the county level is clarified in this work based on both a literature search and fieldwork. More than 3600 publications related to O. sinensis were investigated, including scientific papers, books, and online information. Herbarium specimens of O. sinensis and field collections made by this research group during the years 2000-2010 were examined to verify the distribution sites. A total of 203 localities for O. sinensis have been found, of which 106 are considered as confirmed distribution sites, 65 as possible distribution sites, 29 as excluded distribution sites and three as suspicious distribution sites. The results show that O. sinensis is confined to the Tibetan Plateau and its surrounding regions, including Tibet, Gansu, Qinghai, Sichuan, and Yunnan provinces in China and in certain areas of the southern flank of the Himalayas, in the countries of Bhutan, India and Nepal, with 3,000 m as the lowest altitude for the distribution. The fungus is distributed from the southernmost site in Yulong Naxi Autonomous County in northwestern Yunnan Province to the northernmost site in the Qilian Mountains in Qilian County, Qinghai Province, and from the east edge of the Tibetan Plateau in Wudu County, Gansu Province to the westernmost site in Uttarakhand, India. The clarification of the geographic distribution of O. sinensis will lay the foundation for conservation and sustainable use of the species.

Journal Article

Assessment of Resistomycin, as an Anticancer Compound Isolated and Characterized from Streptomyces aurantiacus AAA5: Rajendran Vijayabharathi , Per Bruheim , Trygve Andreassen , Duraisamy Senthil Raja , Palanisamy Bruntha Devi , Sathyaseelan Sathyabama , Venkatesan Brindha Priyadarisini; J. Microbiol. 2011;49(6):920-926. Published online December 28, 2011; DOI: https://doi.org/10.1007/s12275-011-1260-5

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43 Citations

Abstract: A new actinomycete strain, isolated from humus soils in the Western Ghats, was found to be an efficient pigment producer. The strain, designated AAA5, was identified as a putative Streptomyces aurantiacus strain based on cultural properties, morphology, carbon source utilization, and analysis of the 16S rRNA gene. The strain produced a reddish-brown pigmented compound during the secondary metabolites phase. A yellow compound was derived from the extracted pigment and was identified as the quinone-related antibiotic resistomycin based on ultraviolet–visible spectrophotometry, fourier transform infrared spectroscopy, liquid chromatography and mass spectroscopy, and nuclear magnetic resonance analyses. The AAA5 strain was found to produce large quantities of resistomycin (52.5 mg/L). It showed potent cytotoxic activity against cell lines viz. HepG2 (hepatic carcinoma) and HeLa (cervical carcinoma) in vitro, with growth inhibition (GI50) of 0.006 and 0.005 μg/ml, respectively. The strain also exhibited broad antimicrobial activities against both Gram-positive and Gram-negative bacteria. Therefore, AAA5 may have great potential as an industrial resistomycin-producing strain.

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

Comparative Genomic Analysis of Bacteriophage EP23 Infecting Shigella sonnei and Escherichia coli: Ho-Won Chang , Kyoung-Ho Kim; J. Microbiol. 2011;49(6):927-934. Published online December 28, 2011; DOI: https://doi.org/10.1007/s12275-011-1577-0

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19 Citations

Abstract: Bacteriophage EP23 that infects Escherichia coli and Shigella sonnei was isolated and characterized. The bacteriophage morphology was similar to members of the family Siphoviridae. The 44,077 bp genome was fully sequenced using 454 pyrosequencing. Comparative genomic and phylogenetic analyses showed that EP23 was most closely related to phage SO-1, which infects Sodalis glossinidius and phage SSL-2009a, which infects engineered E. coli. Genomic comparison indicated that EP23 and SO-1 were very similar with each other in terms of gene order and amino acid similarity, even though their hosts were separated in the level of genus. EP23 and SSL-2009a displayed high amino acid similarity between their genes, but there was evidence of several recombination events in SSL-2009a. The results of the comparative genomic analyses further the understanding of the evolution and relationship between EP23 and its bacteriophage relatives.

Identification, Origin, and Evolution of Leaf Nodulating Symbionts of Sericanthe (Rubiaceae): Benny Lemaire , Elmar Robbrecht , Braam van Wyk , Sandra Van Oevelen , Brecht Verstraete , Els Prinsen , Erik Smets , Steven Dessein; J. Microbiol. 2011;49(6):935-941. Published online December 28, 2011; DOI: https://doi.org/10.1007/s12275-011-1163-5

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24 Citations

Abstract: Bacterial leaf symbiosis is an intimate association between bacteria and plants in which endosymbionts are housed within leaf nodules. This phenomenon has been reported in three genera of Rubiaceae (Pavetta, Psychotria, and Sericanthe), but the bacterial partner has only been identified in Psychotria and Pavetta. Here we report the identification of symbiotic bacteria in two leaf nodulating Sericanthe species. Using 16S rRNA data and common housekeeping genetic markers (recA and gyrB) we studied the phylogenetic relationships of bacterial endosymbionts in Rubiaceae. Endosymbionts of leaf nodulating Rubiaceae were found to be closely related and were placed as a monophyletic group within the genus Burkholderia (β-Proteobacteria). The phylogenetic analyses revealed a pattern of strict host specificity and placed the two investigated endosymbionts at two distinct positions in the topology of the tree, suggesting at least two different evolutionary origins. The degree of sequence divergence between the Sericanthe endosymbionts and their relatives was large enough to propose the Sericanthe endosymbionts as new species (‘Candidatus Burkholderia andongensis’ and ‘Candidatus Burkholderia petitii’). In a second part of this study, the pylogenetic relationships among nodulating and non-nodulating Sericanthe species were investigated using sequence data from six chloroplast regions (rps16, trnG, trnL-trnF, petD, petA-psbJ, and atpI-atpH). Overall, genetic variation among the plastid markers was insufficient to enable phylogenetic estimation. However, our results could not rule out the possibility that bacterial leaf symbiosis originated once in a common ancestor of the Sericanthe species.

Isolation and Identification of Lipopeptide Antibiotics from Paenibacillus elgii B69 with Inhibitory Activity Against Methicillin-Resistant Staphylococcus aureus: Rui Ding , Xue-Chang Wu , Chao-Dong Qian , Yi Teng , Ou Li , Zha-Jun Zhan , Yu-Hua Zhao; J. Microbiol. 2011;49(6):942-949. Published online December 28, 2011; DOI: https://doi.org/10.1007/s12275-011-1153-7

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40 Citations

Abstract: Two lipopeptide antibiotics, pelgipeptins C and D, were isolated from Paenibacillus elgii B69 strain. The molecular masses of the two compounds were both determined to be 1,086 Da. Mass-spectrometry, amino acid analysis and NMR spectroscopy indicated that pelgipeptin C was the same compound as BMY-28160, while pelgipeptin D was identified as a new antibiotic of the polypeptin family. These two peptides were active against all the tested microorganisms, including antibiotic-resistant pathogenic bacterial strains such as methicillin-resistant Staphylococcus aureus (MRSA). Time-kill assays demonstrated that pelgipeptin D exhibited rapid and effective bactericidal action against MRSA at 4×MIC. Based on acute toxicity test, the intraperitoneal LD50 value of pelgipeptin D was slightly higher than that of the structurally related antimicrobial agent polymyxin B. Pelgipeptins are highly potent antibacterial and antifungal agents, particularly against MRSA, and warrant further investigation as possible therapeutic agents for bacteria infections resistant to currently available antibiotics.

Expression of the Lactobacillus plantarum malE Gene Is Regulated by CcpA and a MalR-Like Protein: Lidia Muscariello , Valeria Vastano , Rosa A. Siciliano , Margherita Sacco , Rosangela Marasco; J. Microbiol. 2011;49(6):950-955. Published online December 28, 2011; DOI: https://doi.org/10.1007/s12275-011-0495-5

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12 Citations

Abstract: Lactobacillus plantarum is commonly used in the food industry as a starter in various fermentations, especially in vegetable fermentations, in which starch is a common substrate. This polysaccharide, which is obtained from potatoes or corn and is hydrolysed mainly to maltose and glucose by acids or enzymes, is commercially used for the production of lactate by lactic acid fermentation. In this study, we describe the regulation of malE gene expression in L. plantarum. This gene, located in a 7-gene cluster, probably organized in an operon, encodes a putative maltose/maltodextrin-binding protein. We studied the expression of malE in L. plantarum LM3 (wild type) and in LM3-2 (ccpA1), which carries a null mutation in the ccpA gene, encoding the catabolite control protein A (CcpA). In the presence of glucose, expression of the MalE protein was higher in the mutant strain as compared to that in the wild-type strain. Transcription of the malE gene was induced by maltose and regulated by a CcpA-mediated carbon catabolite repression. Further, we isolated strains carrying mutations in 2 genes, lp_0172 and lp_0173, whose deduced amino acid sequences share significant identity with MalR, a regulator of the maltose operon in several gram-positive bacteria. A double mutant exhibited glucose-insensitive malE transcription, while absence of the functional Lp_0172 open reading frame had no effect on malE expression.

Responses in the Expression of Extracellular Proteins in Methicillin-Resistant Staphylococcus aureus Treated with Rhodomyrtone: Monton Visutthi , Potjanee Srimanote , Supayang Piyawan Voravuthikunchai; J. Microbiol. 2011;49(6):956-964. Published online December 28, 2011; DOI: https://doi.org/10.1007/s12275-011-1115-0

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31 Citations

Abstract: Rhodomyrtone from a medicinal plant species, Rhodomyrtus tomentosa, is a challenged effective agent against Gram-positive bacteria, especially methicillin-resistant Staphylococcus aureus (MRSA). The present study was undertaken to provide insight into MRSA extracellular protein expression following rhodomyrtone treatment. Secreteomic approach was performed on a representative clinical MRSA isolate exposing to subinhibitory concentration rhodomyrtone (0.174 μg/ml). The identified extracellular proteins of a response of MRSA to rhodomyrtone treated condition were both suppressed and overexpressed. Staphylococcal antigenic proteins, immunodominant antigen A (IsaA) and staphylococcal secretory antigen (SsaA) involved in cell wall hydrolysis were downregulated after the treatment. The results suggested that rhodomyrtone may interfere with WalK/WalR (YycG/YycF) system. Other enzymes such as lipase precursor and another lipase, glycerophosphoryl diester phosphodiesterase, were absent. In contrast, cytoplasmic proteins such as SpoVG and glycerol phosphate lipoteichoic acid synthase, and ribosomal proteins were found in the treated sample. Appearance of several cytoplasmic proteins in the treated culture supernatant revealed that the bacterial cell wall biosynthesis was disturbed. This finding provides a proteomic mapping of extracellular proteins after rhodomytone treatment. Extensive investigation is required for this natural compound as it has a great potency as an alternative anti-MRSA drug.

Dynamical Analysis of Yeast Protein Interaction Network During the Sake Brewing Process: Mitra Mirzarezaee , Mehdi Sadeghi , Babak N. Araabi; J. Microbiol. 2011;49(6):965-973. Published online December 28, 2011; DOI: https://doi.org/10.1007/s12275-011-1194-y

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1 Citations

Abstract: Proteins interact with each other for performing essential functions of an organism. They change partners to get involved in various processes at different times or locations. Studying variations of protein interactions within a specific process would help better understand the dynamic features of the protein interactions and their functions. We studied the protein interaction network of Saccharomyces cerevisiae (yeast) during the brewing of Japanese sake. In this process, yeast cells are exposed to several stresses. Analysis of protein interaction networks of yeast during this process helps to understand how protein interactions of yeast change during the sake brewing process. We used gene expression profiles of yeast cells for this purpose. Results of our experiments revealed some characteristics and behaviors of yeast hubs and non-hubs and their dynamical changes during the brewing process. We found that just a small portion of the proteins (12.8 to 21.6%) is responsible for the functional changes of the proteins in the sake brewing process. The changes in the number of edges and hubs of the yeast protein interaction networks increase in the first stages of the process and it then decreases at the final stages.

Molecular Characterization of Chloranilic Acid Degradation in Pseudomonas putida TQ07: Luis G. Treviño-Quintanilla , Julio A. Freyre-González , Rosa A. Guillén-Garcés , Clarita Olvera; J. Microbiol. 2011;49(6):974-980. Published online December 28, 2011; DOI: https://doi.org/10.1007/s12275-011-1507-1

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Abstract: Pentachlorophenol is the most toxic and recalcitrant chlorophenol because both aspects are directly proportional to the halogenation degree. Biological and abiotic pentachlorophenol degradation generates p-chloranil, which in neutral to lightly alkaline environmental conditions is hydrolyzed to chloranilic acid that present a violet-reddish coloration in aqueous solution. Several genes of the degradation pathway, cadR-cadCDX, as well as other uncharacterized genes (ORF5 and 6), were isolated from a chloranilic acid degrading bacterium, Pseudomonas putida strain TQ07. The disruption by random mutagenesis of the cadR and cadC genes in TQ07 resulted in a growth deficiency in the presence of chloranilic acid, indicating that these genes are essential for TQ07 growth with chloranilic acid as the sole carbon source. Complementation assays demonstrated that a transposon insertion in mutant CAD82 (cadC) had a polar effect on other genes contained in cosmid pLG3562. These results suggest that at least one of these genes, cadD and cadX, also takes part in chloranilic acid degradation. Based on molecular modeling and function prediction, we strongly suggest that CadC is a pyrone dicarboxylic acid hydrolase and CadD is an aldolase enzyme like dihydrodipicolinate synthase. The results of this study allowed us to propose a novel pathway that offers hypotheses on chloranilic acid degradation (an abiotic by-product of pentachlorophenol) by means of a very clear phenotype that is narrowly related to the capability of Pseudomonas putida strain TQ07 to degrade this benzoquinone.

Shift of Phylogenic Position in Megalocytiviruses Based on Three Different Genes: Se Ryun Kwon , Toyohiko Nishizawa , Jong-Won Park , Myung-Joo Oh; J. Microbiol. 2011;49(6):981-986. Published online December 28, 2011; DOI: https://doi.org/10.1007/s12275-011-1500-8

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12 Citations

Abstract: Major capsid protein (MCP), the adenosine triphosphatase (ATPase), and the PstI fragment genes from five Japanese and three Korean megalocytivirus isolates were sequenced and phylogenetically analyzed with known megalocytiviruses. Phylogenetic trees formed three major clusters (M1, M2, and M3 or P1, P2, and P3), and genogroup I was divided into two minor clusters (M1a/M1b and P1a/P1b) using three target genes. Sequence identity was >97% within each cluster, except cluster II of the PstI fragment (>94% of sequence identity). Interestingly, different genotyping patterns were observed for the same isolates depending on the gene analyzed. The JPN-YelTail and JPN-BfTuna isolates located in the minor M1a cluster, based on MCP and ATPase nucleotide sequences, appeared in the minor P1b cluster based on the PstI fragment, suggesting a shift of phylogenic position in megalocytiviruses. Further study will be conducted to compare the viral antigenicity and pathogenicity between the two isolates showing the shift of phylogenic position and the other isolates clustered within genogroup I.

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