• Food Science of Animal Resources
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• v.43 no.4
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• pp.685-702
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• 2023

Lactic acid bacteria (LAB) are commonly used as probiotics; however, not all LAB strains have the same beneficial effects. To successfully use LAB as probiotics in canines, LAB species should originate from the canine intestinal tract as they display host specificity. The objective of this study was to investigate the phenotypic and genomic traits of potential probiotic LAB isolated from canine fecal samples. Twenty LAB samples were evaluated for their potential probiotic characteristics including resistance to low pH, bile salts, hydrophobicity, auto-aggregation, co-aggregation, adhesion to epithelia or mucosa, and production of inhibitory compounds. Additionally, we evaluated their safety and other beneficial effects on canine health, such as DPPH free radical scavenging, and β-galactosidase. Four strains demonstrated potential probiotic characteristics and were selected: Enterococcus hirae Pom4, Limosilactobacillus fermentum Pom5, Pediococcus pentosaceus Chi8, and Ligilactobacillus animalis FB2. Safety evaluations showed that all strains lacked hemolytic activity, could not produce biogenic amines, and did not carry any pathogenic genes. In addition, L. fermentum Pom5 and P. pentosaceus Chi8 displayed susceptibility to all antibiotics and concordant with the absence of antibiotic resistance genes. Based on their phenotypic and genomic characteristics, L. fermentum Pom5 and P. pentosaceus Chi8 were identified as potential probiotic candidates for canines.

• Mycobiology
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• v.51 no.4
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• pp.195-209
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• 2023

The seed borne disease such as bakanae is difficult to control. Crop yield loss caused by bakanae depending on the regions and varieties grown, ranging from 3.0% to 95.4%. Bakanae is an important disease of rice worldwide and the pathogen was identified as Fusarium fujikuroi Nirenberg (teleomorph: Gibberella fujikuroi Sawada). Currently, four Fusaria (F. fujikuroi, F. proliferatum, F. verticillioides and F. andiyazi) belonging to F. fujikuroi species complex are generally known as the pathogens of bakanae. The infection occurs through both seed and soil-borne transmission. When infection occurs during the heading stage, rice seeds become contaminated. Molecular detection of pathogens of bakanae is important because identification based on morphological and biological characters could lead to incorrect species designation and time-consuming. Seed disinfection has been studied for a long time in Korea for the management of the bakanae disease of rice. As seed disinfectants have been studied to control bakanae, resistance studies to chemicals have been also conducted. Presently biological control and resistant varieties are not widely used. The detection of this pathogen is critical for seed certification and for preventing field infections. In South Korea, bakanae is designated as a regulated pathogen. To provide highly qualified rice seeds to farms, Korea Seed & Variety Service (KSVS) has been producing and distributing certified rice seeds for producing healthy rice in fields. Therefore, the objective of the study is to summarize the recent progress in molecular identification, fungicide resistance, and the management strategy of bakanae.

• The Plant Pathology Journal
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• v.40 no.1
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• pp.59-72
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• 2024

A comprehensive survey of mungbean-growing areas was conducted to observe leaf spot disease caused by Alternaria alternata. Alternaria leaf spot symptoms were observed on the leaves. Diversity of 50 genotypes of mungbean was assessed against A. alternata and data on pathological traits was subjected to cluster analysis. The results showed that genotypes of mungbean were grouped into four clusters based on resistance parameters under the influence of disease. The principal component biplot demonstrated that all the disease-related parameters (% disease incidence, % disease intensity, lesion area, and % of infection) were strongly correlated with each other. Alt a 1 gene that is precisely found in Alternaria species and is responsible for virulence and pathogenicity. Alt a 1 gene was amplified using gene specific primers. The isolated pathogen produced similar symptoms when inoculated on mungbean and tobacco. The sequence analysis of the internal transcribed spacer (ITS) region, a 600 bp fragment amplified using specific primers, ITS1 and ITS2 showed 100% identity with A. alternata. Potato virus X (PVX) -based silencing vector expressing Alt a 1 gene was constructed to control this pathogen through RNA interference in tobacco. Out of 50 inoculated plants, 9 showed delayed onset of disease. Furthermore, to confirm our findings at molecular level semi-quantitative reverse transcriptase polymerase chain reaction was used. Both phenotypic and molecular investigation indicated that RNAi induced through the VIGS vector was efficacious in resisting the pathogen in the model host, Tobacco (Nicotiana tabacum). To the best of our knowledge, this study has been reported for the first time.

• Microbiology and Biotechnology Letters
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• v.47 no.4
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• pp.596-602
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• 2019

In September 2017, the rhizospheric soil of Tetragonia tetragonoides (Pall.) Kuntze was further sampled. One hundred and thirty eight species of microorganisms were isolated from the soil. Indole-3-acetic acid (IAA) production, siderophore production, and phosphate degradation were examined in order to confirm bacterial growth from isolated microorganisms. As a result, most strains were able to produce auxins or siderophores and to solubilize phosphate. In addition, 138 isolated strains were treated with tobacco extract and conferred pathogen resistance to host plants upon treatment. As a result, 35 strains that were able to reduce pathophysiology by more the 60% were selected. Among them, 6 strains with high induced systemic resistance (ISR) activity were found. All of these strains belong to the genus Bacillus according to the 16S rDNA sequence analysis. Bacillus aryabhattai KUDC6619 showed outstanding effects with reduced infection in tobacco and pepper plants. Probably, these Bacillus species play a beneficial role by association with T. tetragonoides for its survival in the harsh conditions found on the island of Dokdo.

• Research in Plant Disease
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• v.20 no.2
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• pp.119-125
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• 2014

Root-knot nematodes represent a significant problem in cucumber, causing reduction in yield and quality. To develop screening methods for resistance of cucumber to root-knot nematode Meloidogyne incognita, development of root-knot nematode of four cucumber cultivars ('Dragonsamchuk', 'Asiastrike', 'Nebakja' and 'Hanelbakdadaki') according to several conditions such as inoculum concentration, plant growth stage and transplanting period was investigated by the number of galls and egg masses produced in each seedling 45 days after inoculation. There was no difference in galls and egg masses according to the tested condition except for inoculum concentration. Reproduction of the nematode on all the tested cultivars according to inoculum concentration increased in a dose-dependent manner. On the basis of the result, the optimum conditions for root-knot development on the cultivars is to transplant period of 1 week, inoculum concentration of 5,000 eggs/plant and plant growth stage of 3-week-old in a greenhouse ($25{\pm}5^{\circ}C$). In addition, under optimum conditions, resistance of 45 commercial cucumber cultivars was evaluated. One rootstock cultivar, Union was moderately resistant to the root-knot nematode. However, no significant difference was in the resistance of the others cultivar. According to the result, we suggest an efficient screening method for new resistant cucumber to the root-knot nematode, M. incognita.

• The Korean Journal of Pesticide Science
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• v.18 no.3
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• pp.161-167
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• 2014

This study was conducted to investigate the resistance of Botrytis cinerea to azoxystrobin, which belongs to strobilurin fungicides. The sensitivity of B. cinerea isolates, which were collected from infected pepper, strawberry, cucumber and tomato by a single spore isolation, to the fungicide was tested through a agar dilution method on PDA amended with fungicides and $100{\mu}g\;mL^{-1}$ of salicylhydroxamic acid (SHAM). All isolates of B. cinerea tested in this study were classified as a sensitive and a resistant group by $1.0{\mu}g\;mL^{-1}$ of $EC_{50}$ value to azoxystrobin. While the sensitive isolates accounted for 46.5% of B. cinerea population, the resistant ones did for 53.5%. According to the regions isolating B. cinerea, the highest isolation frequency was showed as 81.1% in Chungnam among the all. Among 4 host plants as pepper, strawberry, cucumber and tomato, the highest isolation frequency was obtained in strawberry, while the lowest was done in pepper. The isolate resistant to azoxystrobin showed the cross resistance to other fungicides included into strobilurins as kresoxim-methyl and trifloxystrobin. In spite of an excellent efficacy of strobilurins, it should be taken care to use them in the field, because of the high risk in the fields.

• Parasites, Hosts and Diseases
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• v.38 no.4
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• pp.209-236
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• 2000

The last two decades witnessed significant advances in the efforts of immune-parasitologists to elucidate the nature and role of the host mucosal defence mechanisms against intestinal nematode parasites. Aided by recent advances in basic immunology and biotechnology with the concomitant development of well defined laboratory models of infection, immunoparasitologists have more precisely analyzed and defined the different immune effector mechanisms during the infection; resulting in great improvement in our current knowledge and understanding of protective immunity against gastrointestinal (GI) nematode parasites. Much of this current understanding comes from experimental studies in laboratory rodents, which have been used as models of livestock and human GI nematode infections. These rodent studies, which have concentrated on Heligmosomoides polygyrus, Nippostrongylus brasiliensis, Strongyloides ratti/5. venezuelensis. Trichinella spiralis and trichuris muris infections in mice and rats, have helped in defining the types of T cell responses that regulate effector mechanisms and the effector mechanisms responsible for worm expulsion. In addition, these studies bear indications that traditionally accepted mechanisms of resistance such as eosinophilia and IgE responses may not play as important roles in protection as were previously conceived. In this review, we shall, from these rodent studies, attempt an overview of the mucosal and other effector responses against intestinal nematode parasites beginning with the indices of immune protection as a model of the protective immune responses that may occur in animals and man.

• Korean Journal of Veterinary Research
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• v.15 no.1
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• pp.51-55
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• 1975

In this study two sets of experiments were undertaken. Firstly, the embryonated eggs and first-stage larvae, sprayed in disinfected soil, were exposed to different temperatures. Then, the viabilities of them were weekly determined by inoculating the soil to earthworms, Eisenia foetida. Secondly, the infective larvae, seperated from the earthworms and suspended in tap water, were also exposed to different temperatures and their viabilities were checked microscopically at weekly intervals. The results were summerized as follows: 1. The maximum longevities of embryonated eggs and first-stage larvae were determined as 1 week at $35^{\circ}C$, over 36 weeks at $25^{\circ}C$, $15^{\circ}C$, and $5^{\circ}C$, 32 weeks at $-5^{\circ}C$, and under 1 week at $-15^{\circ}C$. 2. The mean numbers of infective larvae detected from the test earthworms were greatest at $5^{\circ}C$, and decreased with rise or fall of the temperature. 3. Infective larvae freed from the intermediate host were able to survive for 2 weeks at $25^{\circ}C$ and 3 weeks at $15^{\circ}C$. However, they lost their viabilities in a week at $35^{\circ}C$, $5^{\circ}C$, $-5^{\circ}C$, and $-15^{\circ}C$. 4. The number of living infective larvae at $15^{\circ}C$ was greater than at $25^{\circ}C$.

• ETRI Journal
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• v.30 no.6
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• pp.790-798
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• 2008

Recently, NAND flash memory has emerged as a next generation storage device because it has several advantages, such as low power consumption, shock resistance, and so on. However, it is necessary to use a flash translation layer (FTL) to intermediate between NAND flash memory and conventional file systems because of the unique hardware characteristics of flash memory. This paper proposes a new clustered FTL (CFTL) that uses clustered hash tables and a two-level software cache technique. The CFTL can anticipate consecutive addresses from the host because the clustered hash table uses the locality of reference in a large address space. It also adaptively switches logical addresses to physical addresses in the flash memory by using block mapping, page mapping, and a two-level software cache technique. Furthermore, anticipatory I/O management using continuity counters and a prefetch scheme enables fast address translation. Experimental results show that the proposed address translation mechanism for CFTL provides better performance in address translation and memory space usage than the well-known NAND FTL (NFTL) and adaptive FTL (AFTL).

• The Plant Pathology Journal
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• v.23 no.2
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• pp.62-69
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• 2007

Twenty-nine isolates of Fusarium solani, originally isolated from diseased cotton roots in Egypt, were evaluated for their ability to cause symptoms on four genetically diverse cotton cultivars. Analysis of variance showed highly significant variance among cultivars, and isolates as well as the isolate x genotype interactions were highly significant(p < 0.0001). Although most isolates showed intermediate pathogenicity, there were two groups of isolates that showed significant differences in pathogenicity on all four cultivars. None of the cultivars were found to be immune to any of the isolates. On all cultivars, there were strong significant positive correlations between dry weight and each of preemergence damping-off, survival, and plant height. Considering 75% similarity in virulence, two groups comprising a total of 29 isolates were recognized. Ninety-three percent of the isolates have the same pathogenicity patterns with consistently low pathogenicity, and narrow diversity of virulence. Isolates Fs4 and Fs5 shared the same distinct overall virulence spectrum with consistently high pathogenicity. There was no clear-cut relationship between virulence of the isolates based on reaction pattern on 4 cultivars and each of host genotype, previous crop, and geographic origin.