• Journal of Veterinary Science
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• v.22 no.3
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• pp.36.1-36.12
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• 2021

Background: Mouse hepatitis virus (MHV) A59 is a highly infectious pathogen and starts in the respiratory tract and progresses to systemic infection in laboratory mice. The complement system is an important part of the host immune response to viral infection. It is not clear the role of the classical complement pathway in MHV infection. Objectives: The purpose of this study was to determine the importance of the classical pathway in coronavirus pathogenesis by comparing C1qa KO mice and wild-type mice. Methods: We generated a C1qa KO mouse using CRISPR/Cas9 technology and compared the susceptibility to MHV A59 infection between C1qa KO and wild-type mice. Histopathological and immunohistochemical changes, viral loads, and chemokine expressions in both mice were measured. Results: MHV A59-infected C1qa KO mice showed severe histopathological changes, such as hepatocellular necrosis and interstitial pneumonia, compared to MHV A59-infected wild-type mice. Virus copy numbers in the olfactory bulb, liver, and lungs of C1qa KO mice were significantly higher than those of wild-type mice. The increase in viral copy numbers in C1qa KO mice was consistent with the histopathologic changes in organs. These results indicate that C1qa deficiency enhances susceptibility to MHV A59 systemic infection in mice. In addition, this enhanced susceptibility effect is associated with dramatic elevations in spleen IFN-γ, MIP-1 α, and MCP-1 in C1qa KO mice. Conclusions: These data suggest that C1qa deficiency enhances susceptibility to MHV A59 systemic infection, and activation of the classical complement pathway may be important for protecting the host against MHV A59 infection.

• Journal of Microbiology and Biotechnology
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• v.29 no.9
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• pp.1375-1382
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• 2019

Phenylalanine hydroxylase from Chromobacterium violaceum (CvPAH) is a monomeric enzyme that converts phenylalanine to tyrosine. It shares high amino acid identity and similar structure with a subunit of human phenylalanine hydroxylase that is a tetramer, resulting in the latent application in medications. In this study, semirational design was applied to CvPAH to improve the catalytic ability based on molecular dynamics simulation analyses. Four N-terminal truncated variants and one single point variant were constructed and characterized. The D267P variant showed a 2.1-fold increased thermal stability compared to the wild type, but lower specific activity was noted compared with the wild type. The specific activity of all truncated variants was a greater than 25% increase compared to the wild type, and these variants showed similar or slightly decreased thermostability with the exception of the $N-{\Delta}9$ variant. Notably, the $N-{\Delta}9$ variant exhibited a 1.2-fold increased specific activity, a 1.3-fold increased thermostability and considerably increased catalytic activity under the neutral environment compared with the wild type. These properties of the $N-{\Delta}9$ variant could advance medical and pharmaceutical applications of CvPAH. Our findings indicate that the N-terminus might modulate substrate binding, and are directives for further modification and functional research of PAH and other enzymes.

• Journal of Oral Medicine and Pain
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• v.45 no.4
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• pp.83-88
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• 2020

Purpose: Growth differentiation factor 11 (GDF11) and myostatin (MSTN) are closely-related transforming growth factor β family members reported to play crucial roles in bone formation. We previously reported that, in contrast to MSTN, GDF11 promotes osteogenesis of vertebrae and limbs. GDF11 has been also reported as an important regulator in tooth development by inducing differentiation of pulp stem cells into odontoblasts for reparative dentin formation. The goal of this study was to investigate the differential roles of GDF11 and MSTN in dental and cranial bone formation. Methods: Micro-computed tomography analysis was performed on cranial bones, including frontal, parietal, and interparietal bones, and lower incisors of wild-type, Gdf11 knockout (Gdf11-/-), and Mstn knockout (Mstn-/-) mice. Tissue volume, thickness, and mineral density were evaluated for both cranial bone and lower incisors. Lower incisor lengths were also measured. Because Gdf11-/- mice die shortly after birth, analysis was performed on newborn (P0) mice. Results: Compared to those of Mstn-/- mice, cranial bone volume, thickness, and mineral density levels were all significantly diminished in Gdf11-/- mice. Tissue mineral density of Gdf11-/- mice were also significantly decreased compared to wild-type mice. Likewise, lower incisor length, tissue volume, thickness, and mineral density levels were all significantly reduced in Gdf11-/- mice compared to Mstn-/- mice. Incisor length was also significantly decreased in Gdf11-/- mice compared to wild-type mice. Mstn-/- mice exhibited mildly increased levels of tissue volume, thickness, and density in cranial bone and lower incisor compared to wild-type mice although statistically not significant. Conclusions: Our findings suggest that GDF11, unlike MSTN, endogenously promotes cranial bone and tooth development.

• The Plant Pathology Journal
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• v.37 no.6
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• pp.555-565
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• 2021

Bacteriophages infecting Acidovorax citrulli, the causal agent of bacterial fruit blotch, have been proven to be effective for the prevention and control of this disease. However, the occurrence of bacteriophage-resistant bacteria is one of hurdles in phage biocontrol and the understanding of phage resistance in this bacterium is an essential step. In this study, we aim to investigate possible phage resistance of A. citrulli and relationship between phage resistance and pathogenicity, and to isolate and characterize the genes involved in these phenomena. A phage-resistant and less-virulent mutant named as AC-17-G1 was isolated among 3,264 A. citrulli Tn5 mutants through serial spot assays and plaque assays followed by pathogenicity test using seed coating method. The mutant has the integrated Tn5 in the middle of a cupin protein gene. This mutant recovered its pathogenicity and phage sensitivity by complementation with corresponding wild-type gene. Site-directed mutation of this gene from wild-type by CRISPR/Cas9 system resulted in the loss of pathogenicity and acquisition of phage resistance. The growth of AC-17-G1 in King's B medium was much less than the wild-type, but the growth turned into normal in the medium supplemented with D-mannose 6-phosphate or D-fructose 6-phosphate indicating the cupin protein functions as a phosphomannos isomerase. Sodium dodecyl sulfa analysis of lipopolysaccharide (LPS) extracted from the mutant was smaller than that from wild-type. All these data suggest that the cupin protein is a phosphomannos isomerase involved in LPS synthesis, and LPS is an important determinant of pathogenicity and phage susceptibility of A. citrulli.

• Journal of Crop Science and Biotechnology
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• v.11 no.2
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• pp.111-118
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• 2008

Soybean is sensitive to waterlogging stress, leading to reduce their growth and yield significantly. The objective of this study was to characterize the relative sensitivities of biomass accumulation and specific nodule activity under waterlogging stress between supernoduating mutants, 'SS2-2' and 'Sakukei 4' and their wild-type soybeans, 'Sinpaldalkong 2' and 'Enrei', respectively. Flooding treatment was performed to soybean plants grown in a pot by waterlogging for 15 days from the beginning bloom(R1) stage under natural light. The nodule number and weight were considerably decreased by waterlogging stress. The bleeding sap rate of waterlogging soybean plants was decreased by 78-80% in supernodulating mutants and 65-74% in their wild types compared to control plants. The relative ureide-N content was also decreased by waterlogging and the reduction was high in supernodulating mutants. This may cause the massive reduction of shoot and root dry weight and leaf area in waterlogged soybean plants. There was a varietal difference in response to the waterlogging stress. During the waterlogging, supernodulating mutants maintained higher spad value than their wild types. Particularly, the difference between soybean varieties was clear in low rank leaves from the top. Also, supernodulating mutants showed a weak waterlogging tolerance than their wild types. Under waterlogging conditions, massive nodules were considerably destroyed and specific nodule activity after waterlogging may not be recovered when compared to their wild-type soybeans. Supernodulating mutants showed lower seed yield than their wild types in waterlogging conditions.

• Korean Journal of Veterinary Research
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• v.57 no.4
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• pp.209-214
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• 2017

Wild raccoon dogs (Nyctereutes procyonoides koreensis) may play a role transmitting several pathogens to humans and pet animals. Information concerning the incidence of rabies, canine distemper virus (CDV), canine parvovirus (CPV), canine adenovirus type 2 (CAdV-2), canine parainfluenza virus type 5 (CPIV-5), and canine herpesvirus (CHV) is needed in wild raccoon dogs. In total, 62 brain samples of raccoon dogs were examined for rabies virus (RABV) and CDV, and 49 lung samples were screened for CDV, CAdV-2, CPIV-5, and CHV. No RABV, CAdV-2, CPIV-5, or CHV was identified, but nine CDV antigens (8.1%, 9/111) were detected. Moreover, 174 serum samples from wild raccoon dogs were screened for antibodies against the five major viral pathogens. The overall sero-surveillance against CDV, CPV, CAdV-2, CPIV-5, and CHV in wild raccoon dogs was 60.3%, 52.9%, 59.8%, 23.6%, and 10.3%, respectively. Comparisons of the sero-surveillance of the five pathogens showed that raccoon dogs of Gyeonggi province have slightly higher sero-positive rates against CDV, CPV, and CHV than those of Gangwon province. These results indicate high incidences of CDV, CPV, and CAdV-2 in wild raccoon dogs of two Korean provinces and a latent risk of pathogen transmission to companion and domestic animals.

• Journal of Life Science
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• v.16 no.1
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• pp.131-135
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• 2006

Oligopeptide is known to be an essential nitrogen nutrient for bacterial growth. Oligopeptide can be transported into cytoplasm by a specific transport system, Opp system. Opp system is composed of five proteins, which are transcribed by an operon. These are responsible for oligopeptide binding protein (OppA), permease (OppB and OppC) and energy generation system (OppD and OppF), respectively. Previously, we isolated the opp operon from Vibrio fluvialis and constructed the oppA mutant by allelic exchange method. In this study, we investigated the growth pattern and biofilm production under the different growth condition. When the cells were cultivated using brain heart infusion(BHI) medium, the wild type was faster than the mutant in growth during the exponential phase. However, it showed that the growth pattern of two strains in M9 medium is very similar. The growth of wild type showed better than that of the mutant grown at pH 8. At pH 7, there was no an obvious difference in growth. After 5 mM $H_2O_2$ was treated to the cells $(OD_{600}=1.2)$, the cell survival was examined. The oppA mutation did not affect in survivability. In the presence of $10{\mu}g/ml$ polymyxin B, the biofilm production of the oppA mutant was higher than that of the wild type.

• Journal of Ginseng Research
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• v.30 no.4
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• pp.206-211
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• 2006

To investigate mycorrhizal infection by arbuscular mycorrhizal fungi(AMF), samples of fine lateral roots were taken from the wild ginseng(Panax ginseng C.A. Meyer) naturally growing at various locations in Korea. Mycorrhiazal infections were studied by cleaning the root samples and staining fungal hyphae with frypan blue. Wild ginsengs for this study were graded by an appraisal committee consisting of 12 experts of Korea Mountain Ginseng Association. Following five quality groups were recognized: Heaven group(pure natural), Earth group (from seeding of wild ginseng), Man group(from seeding or seedlings of wild ginseng with slight environmental modification), unmarketable, and imported wild ginseng. Morphology of AMF was typical Paris-type which shows intracellular hyphal coils with rare vesicles and lack of arbuscules. Average infection rate of individual wild ginsengs was 58.3% and showed no differences among five quality groups. When portions of fine roots were quantified for mycorrhizal infection, 18.7% of the total length of the primary and secondary roots were infected by AMF. Wild ginsengs from Gyeonggi Province(84.2%), and from mountains lower than 1,200 meters above sea level(about 70%) showed higher infection rate, while the ginseng from Gyeongbuk Province(27.8%) had lower rate. Wild ginsengs at older age showed lower infection rates.

• Journal of Sensor Science and Technology
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• v.21 no.5
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• pp.374-378
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• 2012

Biofouling causes many problem in industrial processes, medical health industries, water utilities and our daily life. So detecting formation of biofilm on the surface of medical appliance, water pipe and industrial utility is highly important to prevent the problem caused by biofouling. In this study, we suggest an electrochemical sensor for detecting biofilm. We fabricated the electrochemical sensor in MEMS process and cultivated two different kinds of Pseudomonas aeruginosa RpoN type and Wild type on the surface of electrochemical sensor. Each group of Pseudomonas aeruginosa was cultivated according to the hours of 2, 4, 6, 8, 12 and 24. Then we investigated changes in degree of biofilm cultivation using cyclic voltammetry. As a result, it was observed that peak of the cyclic voltammetry curve is increased according as the biofilm growth on the surface of electrochemical sensor. Also we can discern between Pseudomonas aeruginosa RpoN type and Wild type.

• Journal of Microbiology and Biotechnology
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• v.3 no.2
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• pp.95-98
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• 1993

This study was carried out to isolate and characterize the mutant strains of Schwanniomyces castellii NRRL Y-2477. Mutants were prepared with the treatment of ethyl methane sulfonate. 2-deoxy-D-glucose resistant mutants were isolated and two mutants were selected based on their high production of amylolytic enzymes and their ability to ferment starch. The mutants selected had higher a-amylase and glucoamylase activities than the wild type strain from several other carbon sources. Especially, it was revealed that mutant strain M-9, when cultured in the presence of glucose as a sole carbon source, shows relatively high activities of a-amylase and glucoamylase compared to those of the wild type strain. In result, this mutant strain can be considered as a constitutive producer of amylolytic enzymes. To compare the ethanol production ability of wild type strain and of mutant strains selected, an alcohol fermentation was carried out using 100 g/l soluble starch. Mutant strain M-9 did not improve the direct alcohol fermentation of starch, despite its excellent amylolytic activities performance. On the other hand, mutant strain M-6 produced 37.9 g/l (4.8%, v/v) ethanol by utilizing about 82% of substrate.