• Journal of Veterinary Clinics
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• v.27 no.1
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• pp.62-65
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• 2010

Arowana (Scleropages formosus) is the most valuable group of ornamental fishes and very much in demand in the ornamental fish trade and commands high price ranging from hundreds to thousands of dollars per fish. In this paper, we described a case of mortality of arowana from a private aquarium in Korea. A bacterial pathogen from fish organs (brain, kidney, liver) was cultured, identified and confirmed using Vitek System 2, API 20E test, multiplex PCR and 16S rRNA gene sequencing. The morphological and biochemical properties of the bacterium isolated from the brain, kidney and liver of the fish were similar to Aeromonas sobria. Positive amplification products using the multiplex PCR assay for detection of A. sobria were obtained from these organs. The 16S rRNA gene of the isolates from fish was identical and exhibited 100% sequence similarity with A. sobria (AY987762.1) strain available from GenBank. This bacterium contained hemolysin gene, a virulence factor that plays an important role in outbreaks of disease and is pathogenic to humans as well as in fish. Although this opportunistic bacterium was isolated from a fish without any external symptoms, this pathogen may act as a reservoir and enhance chances of zoonosis to human such as during handling.

• The Plant Pathology Journal
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• v.33 no.6
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• pp.543-553
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• 2017

Sesame (Sesamum indicum) is an important oil seed crop of Asia. Yields can be negatively impacted by various factors, including disease, particularly those caused by fungi which create problems in both production and storage. Foliar diseases of sesame such as Alternaria leaf blight may cause significant yield losses, with reductions in plant health and seed quality. The work reported here determined the incidence of Alternaria species infecting sesame seeds grown in the Punjab, Pakistan. A total of 428 Alternaria isolates were obtained from 105 seed samples and grouped into 36 distinct taxonomic groups based on growth pattern and morphological characters. Isolation frequency and relative density of surface sterilized and non-surface sterilized seeds showed that three isolates (A13, A47 and A215) were the most common morphological groups present. These isolates were further identified using sequencing of the Internal Transcribed Spacer (ITS) region of ribosomal DNA (rDNA) and the Alternaria major allergen gene (Alt a 1). Whilst ITS of rDNA did not resolve the isolates into Alternaria species, the Alt a 1 sequences exhibited > 99% homology with Alternaria alternata (KP123850.1) in GenBank accessions. The pathogenicity and virulence of these isolates of Alternaria alternata was confirmed in inoculations of sesame plants resulting in typical symptoms of leaf blight disease. This work confirms the identity of a major source of sesame leaf blight in Pakistan which will aid in formulating effective disease management strategies.

• Journal of Microbiology and Biotechnology
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• v.26 no.4
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• pp.748-756
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• 2016

In the present study, a lipopeptide (named AXLP14) antagonistic to Xanthomonas oryzae pv. oryzae (Xoo) was obtained from the culture supernatant of Bacillus amyloliquefaciens B014. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry analysis demonstrated that AXLP14 consisted of surfactin homologs. The minimum inhibition concentration and minimum bactericidal concentration of AXLP14 against Xoo were determined to be 1.25 and 2.50 mg/ml, respectively. At a concentration of 0.613 mg/ml, AXLP14 strongly inhibited the formation of Xoo biofilm. AXLP14 also inhibited the motility of Xoo in a concentration-dependent manner. Applying AXLP14 to rice seedlings significantly reduced the incidence and severity of disease caused by Xoo. In Xoo-infected rice seedlings, AXLP14 strongly and continuously up-regulated the expression of both OsNPR1 and OsWRKY45. In addition, AXLP14 effectively inhibited the Xoo-induced up-regulation of the expression of the abscisic acid biosynthesis gene OsNECD3 and the abscisic acid signalingresponsive gene OsLip9, indicating that AXLP14 may protect rice against Xoo-induced disease by enhancing salicylic acid defense and interfering with the abscisic acid response to virulence.

• Parasites, Hosts and Diseases
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• v.40 no.1
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• pp.17-24
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• 2002

We have cloned a cDNA encoding a cysteine proteinase of the Acanthamoeba healui OC-3A strain isolated from the brain of a granulomatous amoebic encephalitis patient. A DNA probe for an A. healui cDNA library screening was amplified by PCR using degenerate oligonucleotide primers designed on the basis of conserved amino acids franking the active sites of cysteine and asparagine residues that are conserved in the eukaryotic cysteine proteinases. Cysteine proteinase gene of A. healui (AhCPI) was composed of 330 amino acids with signal sequence, a proposed pro-domain and a predicted active site made up of the catalytic residues, $Cys^{25},{\;}His^{159},{\;}and{\;}Asn^{175}$. Deduced amino acid sequence analysis indicates that AhCPI belong to ERFNIN subfamily of C 1 peptidases. By Northern blot analysis. no direct correlation was observed between AhCPI mRNA expression and virulence of Acanthamoeba, but the gene was expressed at higher level in amoebae isolated from soil than amoeba from clinical samples. These findings raise the possibility that AhCPI protein may play a role in protein metabolism and digestion of phagocytosed bacteria or host tissue debris rather than in invasion of amoebae into host tissue.

• The Plant Pathology Journal
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• v.36 no.4
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• pp.314-322
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• 2020

Interplay between histone acetylation and deacetylation is one of the key components in epigenetic regulation of transcription. Here we report the requirement of MoHDA1-mediated histone deacetylation during asexual development and pathogenesis for the rice blast fungus, Magnaporthe oryzae. Structural similarity and phylogenetic analysis suggested that MoHDA1 is an ortholog of Saccharomyces cerevisiae Hda1, which is a representative member of class II histone deacetylases. Targeted deletion of MoHDA1 caused a little decrease in radial growth and large reduction in asexual sporulation. Comparison of acetylation levels for H3K9 and H3K14 showed that lack of MoHDA1 gene led to significant increase in H3K9 and H3K14 acetylation level, compared to the wild-type and complementation strain, confirming that it is a bona fide histone deacetylase. Expression analysis on some of the key genes involved in asexual reproduction under sporulation-promoting condition showed almost no differences among strains, except for MoCON6 gene, which was up-regulated more than 6-fold in the mutant than wild-type. Although the deletion mutant displayed little defects in germination and subsequent appressorium formation, the mutant was compromised in its ability to cause disease. Wound-inoculation showed that the mutant is impaired in invasive growth as well. We found that the mutant was defective in appressorium-mediated penetration of host, but did not lose the ability to grow on the media containing H₂O₂. Taken together, our data suggest that MoHDA1-dependent histone deacetylation is important for efficient asexual development and infection of host plants in M. oryzae.

• Korean Journal of Pharmacognosy
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• v.45 no.2
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• pp.168-173
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• 2014

The aim of this study was to evaluate the anti-helicobacter activity of the ethanol extract of Sohamhyoongtang (Coptidis Rhizoma, Pinelliae Tuber and Trichosanthis Semen) and Coptidis Rhizoma total alkaloids, which is one of the components of Sohamhyoongtang. Crude ethanol extract of Sohamhyoongtang (ESHHT) and Coptidis Rhizoma total alkaloids (CRTA) were used for this experiment. Five different types of H. pylori (including H. pylori 26695) were used as test strain. To determine anti-helicobacter activity, minimum inhibitory concentration (MIC) was determined by agar dilution method. The effect of ESHHT and CRTA on the gene expression of H. pylori was investigated by quantitative realtime-PCR (qRT-PCR). MICs of ESHHT against five H. pylori strains were $250{\sim}500{\mu}g/ml$ and MICs of CRTA against five H. pylori strains were $50{\sim}200{\mu}g/ml$. Four representative virulence genes of H. pylori, cagA, ureA, ureB and ureI were tested as target genes for qRT-PCR. According to the qRT-PCR results, both ESHHT and CRTA markedly repressed the expression of cagA gene of H. pylori 26695 (6.91 and 20 folds respecively). These results showed that the ESHHT and CRTA demonstrated antihelicobacter properties, suggesting their potential use in gastritis or duodenal ulcer.

• Journal of Microbiology and Biotechnology
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• v.15 no.1
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• pp.175-182
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• 2005

Abstract Salmonella pathogenicity island 1 (SPI1) gene expression is regulated by many environmental signals such as oxygen, osmolarity, and pH. Here, we examined changes in the expression level of various regulatory proteins encoded within SPI1 in response to three different concentrations of NaCl, using primer extension analysis. Transcription of all the regulatory genes tested was activated most when Salmonella were grown in Luria Broth (LB) containing 0.17 M NaCl. The expression of hilA, invF, and hilD was decreased in the presence of 0.47 M NaCl or in the absence of NaCl, while hilC expression was almost constant regardless of the NaCl concentration when Salmonella were grown to exponential phase under low-oxygen condition. The reduced expression of hilA, invF, and hilD resulted in lower invasion of hilC mutant to the cultured animal cells when the mutant was grown in the presence of 0.47 M NaCl or in the absence of NaCl prior to infection. Among the proteins secreted via the SPI1-type III secretion system (TTSS), the level of sopE2 expression was not influenced by medium osmolarity. Various effects of osmolarity on virulence gene regulation observed in this study is one example of multiple regulatory pathways used by Salmonella to cause infection.

• Restorative Dentistry and Endodontics
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• v.27 no.1
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• pp.54-65
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• 2002

Black-pigmented bacteria have been implicated in the endodontic infections. This group of microorganisms includes Porphyromonas endodontalis, Porphyromonas gingivalis, Prevotella intermedia, and Prevotella nigrescens. The organisms display a wide variety of virulence factors that may be pertinent to acute endodontic infections. The aim of this study was to identify P. endodontalis, P. gingivalis, P. intermedia, and P. nigrescens by using special potency disk test, filter paper spot test, 165 rRNA gene-directed PCR, and API 32A. Microbial samples were collected from root canals of 33 intact teeth with necrotic pulp and/or apical periodontitis. Conventional laboratory methods were used for identification of the strains of black pigmented bacteria. Eighteen of 33 samples were positive for the growth of black-pigmented bacteria Five colonies were cultured from each pure cultured colonies from Brucella agar plate. Seventy seven colonies were positive for the growth of black-pigmented bacteria. Thirty three of 77(42.6%) were identifed as P. nigrescens, 10 of 77(12.9%)were P. gingivalis, 6 of 77(7.8%) were P. endodontalis, 10 of 77(12.9%) were P. intermedia. On the contrary the reference strains of P. nigrescens, experimental strains of P nigrescens was sensitive to kanamycin in special potency disk test. 165 rRNA gene PCR and API test after rapid presumptative identification methods, such as special potency disk test and filter paper spot test, would be accurate detection methods for black-pigemented bacteria.

• Korean Journal of Clinical Laboratory Science
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• v.38 no.1
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• pp.45-53
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• 2006

Anaerobic black-pigmented bacteria have been implicated in the endodontic infections. This group of microorganisms includes Porphyromonas endodontalis, P. gingivalis, Prevotella intermedia, and Prevotella nigrescens. The organisms display a wide variety of virulence factors that may be pertinent to acute endodontic infections. The aim of this study was to identify P. endodontalis, P. gingivalis, P. intermedia, and P. nigrescens by using the special potency disk test, filter paper spot test, 16S rRNA gene-directed PCR, and API 32A system. Microbial samples were collected from root canals of 33 intact teeth with necrotic pulp and apical periodontitis. Conventional laboratory methods were used to identify the strains of anaerobic black pigmented bacteria. Eighteen out of 33 samples were positive for the growth of black-pigmented bacrteria. Five colonies were cultured from each pure cultured colony from Brucella agar plates. Seventy seven colonies were positive for the growth of black-pigmented bacteria. Thirty three out of 77(42.8%) were identifed as P. nigrescens, 10 out of 77(13%)were P. gingivalis, 6 out of 77(7.8%) were P. endodontalis, 10 out of 77(13%) were P. intermedia. On the contrary the reference strains of P. nigrescens, experimental strains of P. nigrescens were susceptible to kanamycin in the special potency disk test. We concluded that after rapid presumptive identification methods, such as the special potency disk test and filter paper spot test were done, 16S rRNA gene PCR and API 32A test would be accurate detection methods for black-pigemented bacteria.

• 한국균학회소식:학술대회논문집
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• 2018.05a
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• pp.11-11
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• 2018

Cryphonectria parasitica, chestnut blight fungus, has a characteristic of decreasing pathogenicity when infected with Cryphonectria hypovirus 1. C. parasitica is known to be one of the most representative model systems used to observe the interaction between viruses, plants and fungi. The mitogen-activated protein kinase (MAPK) pathway, which is well conserved in various organisms ranging from yeast to humans, functions in relaying phosphorylation-dependent signals within MAPK cascades to diverse cellular functions involved in the regulation of pheromone, cell wall integrity, and osmotolerance in filamentous fungi. Several genes in the MAPK pathway were revealed to be regulated by hypovirus, or to be involved in pathogenicity in C. parasitica. Among these pathways, the CWI pathway has aroused interest because CpBck1, an ortholog of yeast Bck1 (a CWI MAPKKK), was previously reported to be involved in cell wall integrity and sectorization. Interestingly, sporadic sectorization was observed in the CpBck1 mutant and sectored phenotypes were stably inherited in the progeny that were successively transferred from sectored mycelia. In this study, we analyzed the biological function of CpSlt2, downstream gene of CpBck1, to confirm whether the sectorization phenomenon occurred in the specific single gene or cell wall integrity (CWI) pathway. As results, the CpSlt2-null mutant exhibited marked changes in colonial growth, near absence of conidiation and aerial hyphae, abnormal pigmentation, CWI-related phenotypic defects, and dramatically impaired virulence. As cultivation of the mutant strains progressed, the majority of the colonies showed sporadic sectorization and mycelia from the sectored area stably maintained the sectored phenotype. These results suggest that the unique sectorization is CWI pathway-specific, though the components in the same CWI pathway have common and specific functions.