• Journal of Microbiology and Biotechnology
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• v.32 no.8
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• pp.989-1002
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• 2022

Cephalopods, in particular octopus (Octopus vulgaris), have the ability to alter their appearance or body pattern by showing a wide range of camouflage by virtue of their chromatophores, which contain nanostructured granules of ommochrome pigments. Recently, the antioxidant and antimicrobial activities of ommochromes have become of great interest; therefore, in this study, the pH-dependent redox effect of the extraction solvent on the antioxidant potential and the structural characterization of the pigments were evaluated. Cell viability was determined by the microdilution method in broth by turbidity, MTT, resazurin, as well as fluorescence microscopy kit assays. A Live/Dead Double Staining Kit and an ROS Kit were used to elucidate the possible inhibitory mechanisms of ommochromes against bacterial and fungal strains. The results obtained revealed that the redox state alters the color changes of the ommochromes and is dependent on the pH in the extraction solvent. Natural phenoxazinone (ommochromes) is moderately toxic to the pathogens Staphylococcus aureus, Bacillus subtilis, Salmonella Typhimurium and Candida albicans, while the species Pseudomonas aeruginosa and Pseudomonas fluorescens, and the filamentous fungi Aspergillus parasiticus, Alternaria spp. and Fusarium verticillioides, were tolerant to these pigments. UV/visible spectral scanning and Fourier- transform infrared spectroscopy (FTIR) suggest the presence of reduced ommatin in methanol/ HCl extract with high intrinsic fluorescence.

• The Plant Pathology Journal
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• v.38 no.6
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• pp.656-664
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• 2022

Pectobacterium odoriferum is the primary causative agent in Kimchi cabbage soft-rot diseases. The pathogenic bacteria Pectobacterium genera are responsible for significant yield losses in crops. However, P. odoriferum shares a vast range of hosts with P. carotovorum, P. versatile, and P. brasiliense, and has similar biochemical, phenotypic, and genetic characteristics to these species. Therefore, it is essential to develop a P. odoriferumspecific diagnostic method for soft-rot disease because of the complicated diagnostic process and management as described above. Therefore, in this study, to select P. odoriferum-specific genes, species-specific genes were selected using the data of the P. odoriferum JK2.1 whole genome and similar bacterial species registered with NCBI. Thereafter, the specificity of the selected gene was tested through blast analysis. We identified novel species-specific genes to detect and quantify targeted P. odoriferum and designed specific primer sets targeting HAD family hydrolases. It was confirmed that the selected primer set formed a specific amplicon of 360 bp only in the DNA of P. odoriferum using 29 Pectobacterium species and related species. Furthermore, the population density of P. odoriferum can be estimated without genomic DNA extraction through SYBR Green-based real-time quantitative PCR using a primer set in plants. As a result, the newly developed diagnostic method enables rapid and accurate diagnosis and continuous monitoring of soft-rot disease in Kimchi cabbage without additional procedures from the plant tissue.

• Biomedical Science Letters
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• v.28 no.3
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• pp.186-191
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• 2022

The use of earphones has recently been widely used around the world. In currently, students wear earphones a lot in a daily life. The types of earphones are open-earphones, Canalphones, and headphones. Many students don't periodically to sterilization their earphones. Therefore, it can be an incubator that can induced ear infections. The objective of this study was to detect the pathogenic bacteria from the earphones used by the students. A total of 3 type earphones swabs were collected by sterile cotton swabs. The swabs were inoculated onto BHI agar and incubated aerobically 48 hour at 37℃. 16s rRNA PCR, electrophoresis and sequencing were performed to confirm the identification of all the bacterial isolates. As a result, 24 pathogens were identified in sequencing. Three types of earphones were sterilized in three ways: ultraviolet (UV), 70% ethyl alcohol, and antibacterial wet tissue. If you use earphones for a long time without disinfecting them for a long time, it causes various diseases such as external ear infections. The findings of this study the users periodically to sterilization their respective earphones.

• The Plant Pathology Journal
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• v.38 no.2
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• pp.90-101
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• 2022

Pathogenicity of eight Bacillus strains to seedlings of four cotton cultivars was evaluated under greenhouse conditions. Each of the tested cultivars was individually treated with powdered inoculum of each bacterial strain. Untreated seeds were planted as control treatments in autoclaved soil. Effects of the tested strains on levels and activities of some biochemical components of the infected seedlings were also assayed. The biochemical components included total soluble sugars, total soluble proteins, total free amino acids, peroxidase, polyphenol oxidase, phenols, and lipid peroxidation. ANOVA showed that Bacillus strain (B) was a very highly significant source of variation in damping-off and dry weight. Cotton cultivar (V) was a nonsignificant source of variation in damping-off while it was a significant source of variation in dry weight. B × V interaction was a significant source of variation in damping-off and a nonsignificant source of variation in dry weight. Bacillus strain was the most important source of variation as it accounted for 59.36 and 64.99% of the explained (model) variation in damping-off and dry weight, respectively. The lack of significant correlation between levels and activities of the assayed biochemical components and incidence of damping-off clearly demonstrated that these biochemical components were not involved in the pathogenicity of the tested strains. Therefore, it was hypothesized that the pathogenicity of the tested strains could be due to the effect of cell wall degrading enzymes of pathogenic toxins. Based on the results of the present study, Bacillus strains should be considered in studying the etiology of cotton seedling damping-off.

• Journal of fish pathology
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• v.35 no.1
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• pp.47-56
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• 2022

Lincomycin as one of the lincosamides antibiotics have been mainly used in human and livestock fields, but have not been used in aquaculture. In this study, the distribution of minimum inhibitory concentration (MIC) values against lincomycin and the detection of the macrolide-lincosamide-streptogramin (MLS) resistance gene were confirmed in bacterial pathogens isolated from cultured olive flounder (Paralichthys olivaceus). Of the 107 strains isolated from Jeju, 36 strains of Gram-positive bacteria and 71 strains of Gram-negative bacteria were identified. Most of Streptococcus spp. was found to have a MIC value of less than or equal to 0.5 ㎍/mL, and Edwardsiella piscicida was found to have a MIC value higher than 1,024 ㎍/mL. V. harveyi and V. alginolyticus mostly showed MIC values of 256 ㎍/mL, but V. scophthalmi displayed values of 8~64 ㎍/mL. In the detection of MLS resistance gene, erm(B) was detected in 9 strains of Streptococcus spp., and erm(A) was confirmed in one strain.

• Natural Product Sciences
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• v.29 no.1
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• pp.50-58
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• 2023

The phytochemical investigation of the crude methanolic extracts roots and stem bark of Anthonotha cladantha (Harms) J.Léonard led to the isolation and identification of twelve secondary metabolites: 2,3-dihydroxypropyl hexacosanoate (1), hederagenine (2), cycloeucalenol (3), 2α-hydroxylupeol (4), betulinic acid (5), lupeol (6), heptacosan-2-one (7), triacontanoic acid (8), stigmast-4-en-3-one (9), β-sitosterol (10), stigmasterol (11), and stigmasterol-3-O-β-D-glucopyranoside (12). Their structures were elucidated with the help of their spectroscopic and physical data and by comparison with those reported in the literature. To the best of our knowledge, from all those compounds, 2,3-dihydroxypropyl hexacosanoate (1), hederagenine (2), cycloeucalenol (3), 2α-hydroxylupeol (4), and betulinic acid (5) are being reported for the first time from this genus. In addition, the acetylation of compound 1 afforded a new derivative 3-(hexacosanoyloxy)propane-1,2-diyl diacetate (1a). Compound 1 possessed a moderate α-glucosidase inhibitory activity with an IC₅₀ value of 39.2 ± 0.22 μM; it neither showed antioxidant activity nor inhibition against the enzyme urease. Compound 1a exhibited weak antioxidant activity in the DPPH assay with an IC₅₀ value of 80.3 ± 0.83 μM but was inactive against α-glucosidase and urease. Furthermore, both compounds 1 and 1a were inactive against seven pathogenic bacterial strains.

• Korean Journal of Veterinary Service
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• v.45 no.4
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• pp.277-284
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• 2022

Salmonella is a pathogenic bacterium that has long been important industrially because it has a wide host range and can be transmitted to humans through direct contact as well as indirect contact such as food contaminated with animal waste. Understanding how to reduce Salmonella contamination in pig farms is important for public health and the livestock industry from an economic perspective. In the swine industry, high concentrations of disinfectants have been applied because it is difficult to effectively control Salmonella in environments contaminated with organic substances. In order to evaluate the synergetic effect of disinfectants, the efficacy of two commercial disinfectants diluted in hard water and microbubble water (MBW) were compared under the laboratory condition. Different concentrations of both disinfectants combined with 1% detergent diluted in the two diluents were evaluated for their antibacterial effect. In the case of monopersulfate-based disinfectant groups, the growth of Salmonella was not observed at 1:200 dilution with both the hard water and MBW combined with 1% detergent. In the case of citric acid-based disinfectant, the bacterial growth was not observed at 1:800 dilution with MBW combined with 1% detergent. Our results show that the use of MBW as a diluent might improve the biological activities of acid-based disinfectant.

• Korean Journal of Environmental Biology
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• v.40 no.4
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• pp.398-404
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• 2022

Bis(2-ethylhexyl) phthalate (DEHP) is one of the plasticizers used in the polyvinyl chloride(PVC) industry. It is known to be easily released into the environment. In this study, we investigated effects of DEHP on growth, metabolic pathway, and virulence gene expression in soil-borne bacterial plant pathogen, Pectobacterium carotovorum SCC1 using in vitro assays. As a result, DEHP at 20 ㎍ mL^-1 did not affect the growth, cell membrane permeability, or ATPase activity of P. carotovorum SCC1. However, it decreased succinyl-CoA synthase (SCS) activity in the tricarboxylic acid (TCA) cycle. Relative expression levels of virulence genes encoding pectate lyase and pectin were differentially influenced by DEHP treatment. These results suggest that biological characteristics of P. carotovorum might be influenced by DEHP in soil.

• Food Science of Animal Resources
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• v.42 no.2
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• pp.313-320
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• 2022

Brazil is considered as a great broiler feet exporter, especially for the Chinese trade. Contact lesions at the tibiotarsal region are responsible for economic losses and there is no model for its classification, thereby this study presents a fast and practical grade system to be used in the poultry industry and proposes these lesion characterizations into three different grades. For this, correlation was made between macroscopic, histological findings and microbiological quantification (Escherichia coli, Staphylococcus spp., Streptococcus spp. and sulphite-reducing clostridia) from contact lesions in the tibiotarsal region of 112 broiler carcasses, divided in four groups (n=28), accordingly to the lesion's intensity. There were no significant differences in microbiological quantification among the groups (p>0.05) except for the grade 3 group, as grade 1 and 2 lesions were in the early stages and histopathological changes such as ulceration were not observed. In grade 3 lesion group, it was observed bacterial cocci grume and ulceration at the articular region and significantly higher microbiological count (p<0.05) for E. coli and Staphylococcus spp. In conclusion, the visual standard proposed in this work, correlated and confirmed by the histopathologic, and microbiologic characterization, allows to precise and fast ascertainment of the contact lesion grade in the tibiotarsal regions of broiler carcasses. Moreover, it should be highlighted that grades 1 and 2 alterations are not caused by an inflammatory process caused by pathogenic agents and should not be considered a public health risk.

• Advances in nano research
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• v.14 no.4
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• pp.391-397
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• 2023

This manuscript describes the one-step eco-friendly green fabrication of silver nanoparticles (AgNPs) through the in-situ bio-reduction of an aqueous solution of silver nitrate using Syzygium aromaticum leaf extract. UV-vis spectroscopy shows a characteristic SPR peak around 442 nm. FTIR spectroscopy showed that the AgNPs were capped with bioactive phyto-molecules. TEM images revealed oval and spherical particles with a mean diameter of ~12.6 nm. XRD analysis revealed crystalline and face-cantered cubic AgNPs. The phytosynthesized AgNPs showed broad-spectrum anti-microbial activity against two foodborne pathogenic bacteria, Listeria monocytogenes and Staphylococcus aureus. The AgNPs showed a prominent ability to inhibit biofilms formed by L. monocytogenes and S. aureus in laboratory conditions through a crystal violet assay. The results suggest that the AgNPs could be a novel nanotool to develop effective antimicrobial and anti-biofilm agents in food preservation.