• Journal of Microbiology and Biotechnology
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• v.23 no.12
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• pp.1683-1690
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• 2013

The cyclic AMP receptor protein (CRP) homolog, GlxR, controls the expression of several genes involved in the regulation of diverse physiological processes in Corynebacterium glutamicum. In silico analysis has revealed the presence of glxR binding sites upstream of genes ptsG, adhA, and ald, encoding glucose-specific phosphotransferase system protein, alcohol dehydrogenase (ADH), and acetaldehyde dehydrogenase (ALDH), respectively. However, the involvement of the GlxR-cAMP complex on the expression of these genes has been explored only in vitro. In this study, the expressions of ptsG, adhA, and ald were analyzed in detail using an adenylate cyclase gene (cyaB) deletion mutant and glxR deletion mutant. The specific activities of ADH and ALDH were increased in both the mutants in glucose and glucose plus ethanol media, in contrast to the wild type. In accordance, the promoter activities of adhA and ald were derepressed in the cyaB mutant, indicating that glxR acts as a repressor of adhA. Similarly, both the mutants exhibited derepression of ptsG regardless of the carbon source. These results confirm the involvement of GlxR on the expression of important carbon metabolic genes; adhA, ald, and ptsG.

• Journal of Microbiology and Biotechnology
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• v.19 no.11
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• pp.1475-1481
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• 2009

Anthrax is a zoonotic disease caused by Bacillus anthracis, and well recognized as a potential agent for bioterrorism. B. anthracis can be identified by detecting the virulence factors genes located on two plasmids, pXO1 and pXO2. The aim of the present study was to determine the presence of virulence genes in 27 isolates of B. anthracis isolated from clinical and environmental samples. For this purpose, multiplex PCR and DNA probes were designed to detect protective antigen (pag), edema factor (cya), lethal factor (lef), and capsule (cap) genes. Our results indicated that all the isolates contained all the above virulence genes, suggesting that the isolates were virulent. To the best our knowledge, this is the first study about the determination of virulence marker genes in clinical and environmental isolates of B. anthracis using multiplex PCR and DNA probes in India. We suggest that the above methods can be useful in specific identification of virulent B. anthracis in clinical and environmental samples.

• Journal of Microbiology and Biotechnology
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• v.25 no.8
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• pp.1216-1226
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• 2015

GlxR is considered as a global transcriptional regulator controlling a large number of genes having broad physiological aspects in Corynebacterium glutamicum. However, the expression profile revealing the transcriptional control of glxR has not yet been studied in detail. DNA affinity chromatography experiments revealed the binding of transcriptional regulators SucR, RamB, GlxR, and a GntR-type protein (hereafter denoted as GntR3) to the upstream region of glxR. The binding of different regulators to the glxR promoter was confirmed by EMSA experiments. The expression of glxR was analyzed in detail under various carbon sources in the wild-type and different mutant strains. The sucR and gntR3 deletion mutants showed decreased glxR promoter activities, when compared with the wild type, irrespective of the carbon sources. The promoter activity of glxR was derepressed in the ramB deletion mutant under all the tested carbon sources. These results indicate that SucR and GntR3 are acting as activators of GlxR, while RamB plays a repressor. As expected, the expression of glxR in the cyaB and glxR deletion mutants was derepressed under different media conditions, indicating that GlxR is autoregulated.

• Mycobiology
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• v.49 no.6
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• pp.534-550
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• 2021

During a survey of fungal diversity associated with insects, mud, soil, and freshwater niches in different areas in Korea, nine interesting fungal strains were isolated. Based on their morphological characteristics and molecular phylogeny analyses, using a combined data set of b-tubulin (BenA), calmodulin (CaM), and second largest subunit of RNA polymerase (RPB2) sequences, the strains CNUFC AM-44, CNUFC JCW3-4, CNUFC S708, CNUFC WT202, CNUFC AS1-29, CNUFC JCW3-5, CNUFC JDP37, and CNUFC JDP62 were identified as Aspergillus alabamensis, A. floridensis, A. subversicolor, Penicillium flavigenum, P. laevigatum, P. lenticrescens, Talaromyces adpressus, and T. beijingensis, respectively. The strain CNUFC JT1301 belongs to series Westlingiorum in section Citrina and is phylogenetically related to P. manginii. However, slow growth when cultivated on CYA, MEA, CREA is observed and the property can be used to easily distinguish the new species from these species. Additionally, P. manginii is known to produce sclerotia, while CNUFC JT1301 strain does not. Herein, the new fungal species is proposed as P. aquadulcis sp. nov. Eight species, A. alabamensis, A. floridensis, A. subversicolor, P. flavigenum, P. laevigatum, P. lenticrescens, T. adpressus, and T. beijingensis, have not been previously reported in Korea. The present study expands the known distribution of fungal species belonging to the families Aspergillaceae and Trichocomaceae in Korea.

• Journal of Microbiology and Biotechnology
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• v.31 no.7
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• pp.912-920
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• 2021

SOS response is a conserved response to DNA damage in prokaryotes and is negatively regulated by LexA protein, which recognizes specifically an "SOS-box" motif present in the promoter region of SOS genes. Myxococcus xanthus DK1622 possesses a lexA gene, and while the deletion of lexA had no significant effect on either bacterial morphology, UV-C resistance, or sporulation, it did delay growth. UV-C radiation resulted in 651 upregulated genes in M. xanthus, including the typical SOS genes lexA, recA, uvrA, recN and so on, mostly enriched in the pathways of DNA replication and repair, secondary metabolism, and signal transduction. The UV-irradiated lexA mutant also showed the induced expression of SOS genes and these SOS genes enriched into a similar pathway profile to that of wild-type strain. Without irradiation treatment, the absence of LexA enhanced the expression of 122 genes that were not enriched in any pathway. Further analysis of the promoter sequence revealed that in the 122 genes, only the promoters of recA2, lexA and an operon composed of three genes (pafB, pafC and cyaA) had SOS box sequence to which the LexA protein is bound directly. These results update our current understanding of SOS response in M. xanthus and show that UV induces more genes involved in secondary metabolism and signal transduction in addition to DNA replication and repair; and while the canonical LexA-dependent regulation on SOS response has shrunk, only 5 SOS genes are directly repressed by LexA.