• Journal of Dairy Science and Biotechnology
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• v.36 no.4
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• pp.208-219
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• 2018

Emergence of drug resistant strains of Salmonella enterica threatens milk processing and related dairy industries, thereby increasing the need for development of new anti-bacterials. Developments of antibacterial drugs are largely aimed to target the bacterial envelope, but screening their efficacy on bacterial envelope is laborious. This study presents a potential biosensor for envelope-specific stress in which a gfp reporter gene fused to spy gene encoding a periplasmic chaperone protein Spy (spheroplast protein y) that can sense envelope stress signals transduced by two major two-component signal transduction systems BaeSR and CpxAR in Salmonella enterica serovars Enteritidis and S. Gallinarum. Using spy-gfp operon fusions in S. Enterititis and S. Gallinarum, we found that spy transcription in both serovars was greatly induced when Salmonella cells were forming the spheroplast and were treated with ethanol or a membrane-disrupting antibiotic polymyxin B. These envelope stress-specific inductions of spy transcription were abrogated in mutant Salmonella lacking either BaeR or CpxR. Results illustrate that induction of Spy expression can be efficiently triggered by two-component signal transduction systems sensing envelope stress conditions, and thereby suggest that monitoring the spy transcription by spy-gfp operon fusions would be helpful to determine if developing antimicrobials can damage envelopes of S. Enteritidis and S. Gallinarum.

• Microbiology and Biotechnology Letters
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• v.49 no.3
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• pp.391-402
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• 2021

Earthworms play an important role in soil fertilization, interacting continually with microorganisms. This study aims to demonstrate the existence of beneficial microorganisms living in the earthworm's immune system, the coelomic fluid. To achieve this goal, a molecular identification technique was performed, using cytochrome c oxidase I (COI) barcoding to identify abundant endogenic earthworms inhabiting the temperate zone of Rabat, Morocco. Then, 16S rDNA and ITS sequencing techniques were adopted for bacteria and fungi, respectively. Biochemical analysis, showed the ability of bacteria to produce characteristic enzymes and utilize substrates. Qualitative screening of plant growth-promoting traits, including nitrogen fixation, phosphate and potassium solubilization, and indole acetic acid (IAA) production, was also performed. The result of mitochondrial COI barcoding allowed the identification of the earthworm species Aporrectodea molleri. Phenotypic and genotypic studies of the sixteen isolated bacteria and the two isolated fungi showed that they belong to the Pseudomonas, Aeromonas, Bacillus, Buttiauxella, Enterobacter, Pantoea, and Raoultella, and the Penicillium genera, respectively. Most of the isolated bacteria in the coelomic fluid showed the ability to produce β-glucosidase, β-glucosaminidase, Glutamyl-β-naphthylamidase, and aminopeptidase enzymes, utilizing substrates like aliphatic thiol, sorbitol, and fatty acid ester. Furthermore, three bacteria were able to fix nitrogen, solubilize phosphate and potassium, and produce IAA. This initial study demonstrated that despite the immune property of earthworms' coelomic fluid, it harbors beneficial microorganisms. Thus, the presence of resistant microorganisms in the earthworm's immune system highlights a possible selection process at the coelomic fluid level.

• Proceedings of the Korean Society of Crop Science Conference
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• 2022.10a
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• pp.30-30
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• 2022

Philippines is the second world supplier of coconut by-products. As its first major genomics project, the Philippine Genome Center program for Agriculture (PGC-Agriculture) took the challenge to sequence and assemble the whole coconut genome. The project aims to provide advance genetics tools for our collaborating coconut researchers while taking the opportunity to initiate local capacity. Combination of different NGS platforms was explored and the Philippine 'Catigan Green Dwarf' (CATD) variety was selected with the breeders to be the crop's reference genome. A high quality genome assembly of CATD was generated and used to characterize important genes of coconut towards the development of resilient and outstanding varieties especially for added high-value traits. The talk will present the significant results of the project as published in various papers including the first report of whole genome sequence of a dwarf coconut variety. Updates will include the challenges hurdled and specific applications such as gene mining for host insect resistance and screening for least damaged coconuts (thus potentially insect resistant varieties). Genome-wide DNA markers as published and genes related to coconut oil qualitative/quantitative traits will also be presented, including initial molecular/biochemical studies that support nutritional and medicinal claims. A web-based genome database is currently built for ease access and wider utility of these genomics tools. Indeed, a major milestone accomplished by the coconut genomics research team, which was facilitated with the all-out government support and strong collaboration among multidisciplinary experts and partnership with advance research institutes.

• Korean Journal of Breeding Science
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• v.42 no.5
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• pp.555-564
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• 2010

Aphid and mite are the major insects that harm corn. These insects are difficult to control because they are very sensitive to environmental conditions. The purpose of this experiment was to information the loss in quantity of corn and to select inbred lines with resistance after exposing corn to aphid and mite. When exposed to aphid, the average loss in grain yield, ear length, ear diameter, 100 kernel weight, kernel length, kernel width, and kernel thickness were 18.4, 10.9, 1.7, 5.4, 2.3, 1.5 and -0.2%, respectively. When exposed to mite, the average loss in grain yield, ear length, ear diameter, 100 kernel weight, kernel length, kernel width, and kernel thickness were 49.7, 16.5, 20.7, 18.9, 9.5, and -3.4, respectively. Mite had more significant impact on the loss than aphid. Among these factors, grain yield and ear dimater were most significantly correlated on the loss to aphid ($r=0.83^{**}$), while kernel length and thickness were most significantly correlated on the loss to mite ($r=0.83^{**}$). However, ear length was not related to loss to the two insects. The inbred lines that were often used for $F_1$ hybrid which was lower than the average loss by aphid, were KS7, B68, 61B3, 70A1, and KS5, while the inbred lines that were often used for $F_1$ hybrid which was lower than the average decrease by mite, were KS7, B68, 61B3, 66B2-4, 70A1, 72B2, and KS5. These inbred lines could be used to breed inbred lines, hybrid, and open pollination variety that confer resistant to aphid and mite.

• Journal of Plant Biotechnology
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• v.49 no.3
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• pp.240-249
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• 2022

Measuring chlorophyll fluorescence (CF) is a useful tool for assessing a plant's ability to tolerate abiotic stresses such as drought, waterlogging and high temperature. Korean ginseng is highly sensitive to water stress in paddy fields. To evaluate the possibility of non-destructively diagnosing waterlogging stress using chlorophyll fluorescence (CF) imaging techniques, we screened 57 ginseng accessions for waterlogging tolerance. To evaluate waterlogging tolerance among the 2-year-old Korean ginseng accessions, we treated ginseng plants with water stress for 25 days. The physiological disorder rate was characterized through visual assessment (an assigned score of 0-5). The physiological disorder rates of Geumjin, Geumsun and GS00-58 were lower than that of other accessions. In contrast, lines GS97-62, GS97-69 and GS98-1-5 were deemed susceptible. Root traits, chlorophyll content and the reduction rates decreased in most ginseng accessions. Further, these metrics were significantly lower in susceptible genotypes compared to resistant ones. All CF parameters showed a positive or negative response to waterlogging stress, and this response continuously increased over the treatment time among the genotypes. The CF parameter Fv/Fm was used to screen the 57 accessions, and the results showed clear differences in Fv/Fm between the susceptible and resistant genotypes. Susceptible genotypes had an especially low Fv/Fm value of less than 0.8, reflecting damage to the reaction center of photosystem II. It is concluded that Fv/Fm can be used as a CF parameter index for screening waterlogging stress tolerance in ginseng genotypes.

• Microbiology and Biotechnology Letters
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• v.33 no.1
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• pp.41-50
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• 2005

An organic acid tolerance mutant (M-200) was obtained from Leuconostoc mesenteroides KCCM 35471, followed by the screening procedure using a specific organic acid medium (lactic acid: acetic acid, 2:1). The characteristics of the acid tolerance M-200 and the wild type LM-W were examined at various temperature and pH ranges $(l0-30^{\circ}C$ of temp, 3.5-4.5 of pH). The growth of strain M-200 at HCl adjusted medium $(10^{\circ}C\;and\;pH 3.5)$ was observed. In the case of organic acid adjusted medium, the strain showed its growth at the pH range of 3.8. When the strain M-200 was used as a starter for Kimchi fermentation, a constant acid level (0.55) was observed during the whole fermentation period. This result indicates that the strain produces a proper level of acid content for the Kimchi fermentation. This result also indicates that the edible period of Kimchi can be extended to 3.5 fold compare to the result obtained from the LM-W used Kimchi fermentation. However the excess use of the strain M-200 showed the inhibition of growth of Lactobacillus plantarum, low lactic acid level content and low level of organoleptic test. In the case of organic acid content during the Kimchi fermentation, the strain M-200 showed relatively low production rate compare to the wild type (M-200: 3.5 mg/L at 21 days of fermentation, LM-W: 7 mg/L at 21 days of fermentation). Therefore a mixed Kimchi starter containing M-200 and other strains probably maintain a good Kimchi quality during the fermentation.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.63 no.3
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• pp.257-264
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• 2018

The recent global climate change induced the drought, flooding, and insect pest outbreaks. These caused the severe damage to crop yield in the domesticated field and occurrence change of insect pest species. The sap-sucking insect pest, aphids are common in soybean [Glycine max (L.) Merr.] and cause serious yield losses. Thus, developing resistance cultivars is promising and efficient strategy to prevent the significant yield losses by aphid and screening germplasm is the essential procedure to achieve this goal. We tried to establish a resistance test indicator for foxglove aphid, Aulacorthum solani (Kaltenbach), in soybean and found that plant damage degree or infested plant damage is most suitable one. Also we screened around 1,200 of soybean germplasm including wild and cultivated species for its resistance to foxglove aphid from the various origins, and 67 soybeans, including PI 366121, showed antixenosis resistance, 31 germplasms among 67 antixenosis germplasms were showed antibiosis to foxglove aphid with non-choice test. The identified foxglove aphid resistant soybean resources showed significantly low rate in survival test. Furthermore, resistance type, (i.e., antibiosis or antixenosis) of each candidate were varied. In this research, we established the screening index for foxglove aphid resistance in soybean, and identified the resistance varieties. This result could be useful resources in breeding for new foxglove aphid resistance soybean cultivars, and provide fundamental information to investigate the resistance mechanism in soybean.

• Tuberculosis and Respiratory Diseases
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• v.50 no.1
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• pp.29-41
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• 2001

Background : The appearance of multiple-drug-resistant Mycobacterium tuberculosis strains has been seriously compromising successful control of tuberculosis. Rifampin-resistance, caused by mutations in the rpoB gene, can be indicative of multiple-drug-resistance, and its detection is of great importance. The present study aimed to develop an oligonucleotide chip for accurate and convenient screening of drug-resistance. Methods : In order to detect point mutations in the rpoB gene, an oligonucleotide chip was prepared by immobilizing specific probe DNA to a microscopic slide glass by a chemical reaction. The probe DNA that was selected from the 81 bp core region of the rpoB gene was designed to have mutation sites at the center. A total of 17 mutant probes related to rifampin-resistance including 8 rifabutin-sensitive mutant probes were used in this study. For accurate determination, wild type probes were prepared for each mutation position with an equal length, which enabled a direct comparison of the hybridization intensities between the mutant and wild type. Results : Mycobacterial genomic DNA from clinical samples was tested with the oligonucleotide chip and the results were compared with those of the drug-susceptibility test in addition to sequencing and INNO-LiPA Rif. TB kit test in some cases. Out of 15 samples, the oligonucleotide chip results of 13 samples showed good agreement with the rifabutin-sensitivity results. The two samples with conflicting result also showed a discrepancy between the other tests, suggesting such possibilities as existence of mixed strains and difference in drug-sensitivity. Further verification of these samples in addition to more case studies are required before the final evaluation of the oligonucleotide chip can be made. Conlcusion : An oligonucleotide chip was developed for the detection of rpoB gene mutations related to drugsusceptibility. The results to date show the potential for using the oligonucleotide chip for accurate and convenient screening of drug-resistance to provide useful information in antituberculosis drug therapy.

• Korean journal of applied entomology
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• v.39 no.3
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• pp.157-163
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• 2000

In a previous report, 50 potato cultivars were screened for infestation levels by the coppery click beetle (Selatosomus puncticollis Motschulsky) in the field. Subsequently, we selected 10 potato cultivars (Anco, Atlantic, Bintje, Dejima, Denali, Jopung, Irish Cobbler, Namsuh, Shepody, and Superior) to evaluate feeding preferences by wireworms, and to analyze some factors associated with resistance. The injury rates and number of holes in potato tubers damaged by larvae of S. puncticollis were checked in the field and laboratory. Additionally, some of their chemical characters (contents of glycoalkaloids, total-nitrogen, Ca, K, Mg, sugars, and starch) were quantified. And finally correlation analysis was conducted to see whether there is a possible relationship between these characteristics and the damage level. The tuber injury rates by S. puncticollis larvae were generally high showing 19% to 73% of damage level. The highest number of tuber hole damaged by S. puncticollis larvae was found on cv. Namsuh, but generally fewer on cvs. Anco, Atlantic, Bintje, Denali and Superior. No activities for $\alpha$-chaconine, $\alpha$-solanine and $\alpha$-tomatine at a concentration of 2,500 ppm were found to S. puncticollis larvae. The contents of glycoalkaloids in tuber were different depending on cultivars. In tubers, cv. Superior contained the highest level of 18.8 mg%, but cv. Irish Cobbler had the lowest level of 6.39 mg%. Concentrations of reducing sugars and total free sugars in tubers of cv. Namsuh were 0.71 % and 2.95%, but 0.26% and 1.77% in those of cv. Dejima, respectively. For the content of potato starch, cvs. Bintje, Dejima and Irish Cobbler showed higher level, but cvs. Jopung and Shepody lower. The highest contents of total nitrogen, Ca, K and Mg in tuber were found on cvs. Anco, Atlantic, Anco and Jopung, respectively. From correlation analyses, injury rate by S. puncticollis larvae was correlated with total nitrogen content (r = -0.71435*) and total sugar content in tuber (r = 0.78018*). Such information will become essential in developing integrated pest management programs and also in breeding new potato cultivars resistant to the wireworms.

• Research in Plant Disease
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• v.20 no.4
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• pp.299-302
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• 2014

The Paprika plant infected with Pepper mild mottle virus (PMMoV) do not produce commercial fruit as causing necrotic spots symptom on the fruit. Ten cultivars of paprika were analyzed to select the resistance cultivars against PMMoV pathotypes, $P_{1.2}$ and $P_{1.2.3}$, using bioassay and genetic markers. $L^1$, $L^3$, and $L^4$ genotypes expressing resistance to the pathotypes existed in those cultivars but $L^2$ genotype did not. $L^4L^4$ in cvs. Easy and Magnifico, $L^4L^3$ in cvs. Scirocco and Orange glory F1, $L^4L^1$ in cv. Special F1, $L^3L^3$ in cvs. Fiesta, Piero and Derby, and $L^3L^1$ in Cupra and Mazzona F1 were identified with SCAR and CAPS markers. The resistant cvs. to the 2 pathotypes were Magnipico, Easy, Scirocco F1, Orange glory and Special F1 and the susceptible cvs. were Fiesta, Piero, Derby, Cupra and Mazzona F1. The susceptible cvs. of the absence of $L^4$ genotype showed systemic infection when inoculated with PMMoV-$P_{1.2.3}$. However, those cvs. despite the presence of $L^3$ genotype showed vein necrosis on the inoculated leaf and hypersensitive necrosis symptom on the upper parts when inoculated with PMMoV-$P_{1.2}$.