• Journal of Life Science
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• v.30 no.11
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• pp.947-955
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• 2020

The foot-and-mouth disease virus (FMDV), a member of the Aphthovirus genus in the Picornaviridae family, affects wild and domesticated ruminants and pigs. During replication of the FMDV RNA (ribonucleic acid) genome, FMDV-encoding RNA polymerase 3D acts in a highly location-specific manner. This suggests that specific RNA structures recognized by 3D polymerase within non-coding regions of the FMDV genome assist with binding during replication. One such region is the cis-acting replication element (CRE), which functions as a template for RNA replication. The FMDV CRE adopts a stem-loop conformation with an extended duplex stem, supporting a novel 15-17 nucleotide loop that derives stability from base-stacking interactions, with the exact RNA nucleotide sequence of the CRE producing different RNA secondary structures. Here, we show that CRE sequences of FMDVs isolated in Korea from 2010 to 2017 exhibit A and O genotypes. Interestingly, variations in the RNA secondary structure of the Korean FMDVs are consistent with the phylogenetic relationships between these viruses and reveal the specificity of FMDV infections for particular host species. Therefore, we conclude that each genetic clade of Korean FMDV is characterized by a unique functional CRE and that the evolutionary success of new genetic lineages may be associated with the invention of a novel CRE motif. Therefore, we propose that the specific RNA structure of a CRE is an additional criterion for FMDV classification dependent on the host species. These findings will help correctly analyze CRE sequences and indicate the specificity of host species for future FMDV epidemics.

• Research in Plant Disease
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• v.23 no.4
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• pp.314-321
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• 2017

Acidovorax valerianellae had been reported a causal agent of bacterial black spot disease on corn salad in France, 2003 and on watermelon in Korea 2011. In this study, difference in host specificity between 2 groups, corn salad strains and watermelon strains, of Acidovorax valerianellae was recognized and compared. In the pathogenicity test, all 5 watermelon strains showed pathogenicity on the 6 Cucurbitaceae plants but not on corn salad, whereas 4 corn salad strains showed pathogenicity only on the corn salad. Utilization of Biolog substrates was different between watermelon strains and corn salad strains on 4 substrates, Malonic Acid, ${\alpha}-Hydroxybutyric$ Acid, ${\alpha}-Keto$ Butyric Acid, and Glycyl-L Glutamic Acid. The phylogenetic tree built with the 16S rDNA sequences showed that all of A. valerianellae stains was grouped into 1 clade separating from the other species of Acidovorax genus. Within A. valerianellae clade, watermelon strains and corn salad strains were separated into 2 sub-groups. REP-PCR analysis also separated the two groups. Host specificity, substrate utilization, and some genetic characteristics suggested that there are two pathogenic groups, watermelon group and corn salad group in A. valerianellae.

• Journal of the East Asian Society of Dietary Life
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• v.19 no.2
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• pp.295-300
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• 2009

The specificity and sensitivity of oligonucleotide primers were examined for the rapid detection of Salmonella in meat samples. The oligonucleotide primers used in this study were designed with the modification of mdh and invA sequence in the chromosome of Salmonella Typhimurium. Through the subsequent analysis of the specificity and sensitivity of the primers, two types of oligonucleotide primers, SLM1 and SLT4 were selected for the detection of Salmonella genus specific and S. Typhimurium species specific, respectively. The lowest detection limit of each primer was represented as 1 cell per reaction when reacted with a prepared DNA solution. The detection efficiency of the two primers was analysed with beef and pork samples intentionally contaminated with a mixture of Salmonella culture, and three preparation methods -, namely direct reaction after extraction, enrichment after extraction, and DNA extraction after enrichment for PCR reaction, - were also compared. No differences were found in the results according to meat sources and preparation methods.

• Korean Journal Plant Pathology
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• v.3 no.3
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• pp.217-222
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• 1987

Pathogenicity of nine Rhizoctonia solani isolates of different anastomosis groups (AG) on seed and hypocotyls of red pepper, cucumber, Chinese cabbage and radish varied considerably from nonvirulent to highly virulent. Rhizoctonia solani AG 1 was highly virulent on the above four plant species. AG 2 type 1 was highly virulent on radish and Chinese cabbage, moderately virulent on red pepper, and AG 2 type 2 was avirulent or weakly virulent except red pepper. R. solani AG 5 was moderately virulent on hosts tested. In general, virulence of the R. solani isolates to a given host varied among anastomosis groups, but not within anastomosis groups. Anastomosis groups lacked host specificity. The pathogenicity was stronger in steam-sterilized soil than in non-sterilized field soil, if the inoculated plants were closely related with orginal host from which the pathogen was isolated. On the other hand, pathogen was more virulent in non-sterilized field soil than in steam-sterilized soil, if the inoculated ones were not closely related. Generally, contrary to other soil-brone plant pathogenic fungi, Rhizoctonia isolates tended to be more virulent in non-sterilized field soil than in the same soil which had been steamed. A potential danger of building up propagules of R. solani in southern horticultural area are discussed in terms of cropping system.

• Korean Journal of Environmental Agriculture
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• v.3 no.2
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• pp.43-49
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• 1984

The acute toxicity of an insecticide cartap to several species of freshwater animals was evaluated in the laboratory with special reference to the species specificity, effects of water temperatures and pH values. The aquatic animals tested were the Carassius auratus L., Aphyocypris chinensis $G{\"{U}}NTHER$, Misgurus anguillicaudatus CANTOR, Moina macrocopa STRAUS. The susceptibility of aquatic animals to cartap was different with the species of animals. At the water temperature of $25^{\circ}C$ and pH 7, TLm values of the insecticide to the C. auratus L., A. chinensis G. and M. anguillicaudatus were 0.88, 0.26 and 0.13 ppm in 48 hours, respectively, and to Moina macrocopa S., 306 ppm in 3 hrs. In the case of the three species of fish, TLm 48 values were significantly decreased with rise in temperature. In the case of water flea, where TLm value was 107 ppm at $20^{\circ}C$, there was no consistent response to temperature change, with the highest figure at $25^{\circ}C$ than at either 20 or $30^{\circ}C$. and the susceptibility of C.auratus L. and A. chinensis G. greatly decreased with the increase of pH in water. The toxicity to M. anguillicaudatus and M. macrocopa was significantly higher at pH 9 than at pH 6 or 7. In conclusion, the toxicological reactions of the freshwater animals to cartap were variably influenced by the water temperatures and pH values of water and species of animals.

• Journal of Life Science
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• v.18 no.2
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• pp.284-286
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• 2008

Octopus minor (O. minor) is widely distributed along the coastal regions of Korea, but most of them are caught in southern waters which are associated with one of the important fisheries stock. At present, O. minor from China has been introduced to the fishery markets in Korea. Here, we attempt to discriminate their origin for Korea or China using molecular techniques. Based on the O. minor mitochondrial DNA sequence, we developed a PCR-based origin discrimination system. The assay specificity was assessed by testing four individuals of O. minor from Sangdong, China, as well as 20 additional O. minor from Namhae, Muan, Yeosu and Jindo, Korea. Only four isolates of O. minor originated from China tested as positive in our distinction system. All PCR-positive products yielded identical sequences from Chinese O. minor, whereas Korean O. minor appeared to be PCR amplification. This result suggested that the primers used in this study are O. minor species specific, especially originated from China. The detection system appeared to be positive results in the use of 0.1 ng of Chinese O. minor DNA as template, however, the Korean O. minor even using $1{\mu}g$ of DNA showed no amplification. Consequently, the assay provides a simple, rapid and accurate method for the detection of Chinese O. minor.

• Parasites, Hosts and Diseases
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• v.51 no.4
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• pp.401-412
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• 2013

Because of an increased number of Acanthamoeba keratitis (AK) along with associated disease burdens, medical professionals have become more aware of this pathogen in recent years. In this study, by analyzing both the nuclear 18S small subunit ribosomal RNA (18S rRNA) and mitochondrial 16S rRNA gene loci, 27 clinical Acanthamoeba strains that caused AK in Japan were classified into 3 genotypes, T3 (3 strains), T4 (23 strains), and T5 (one strain). Most haplotypes were identical to the reference haplotypes reported from all over the world, and thus no specificity of the haplotype distribution in Japan was found. The T4 sub-genotype analysis using the 16S rRNA gene locus also revealed a clear subconformation within the T4 cluster, and lead to the recognition of a new sub-genotype T4i, in addition to the previously reported sub-genotypes T4a-T4h. Furthermore, 9 out of 23 strains in the T4 genotype were identified to a specific haplotype (AF479533), which seems to be a causal haplotype of AK. While heterozygous nuclear haplotypes were observed from 2 strains, the mitochondrial haplotypes were homozygous as T4 genotype in the both strains, and suggested a possibility of nuclear hybridization (mating reproduction) between different strains in Acanthamoeba. The nuclear 18S rRNA gene and mitochondrial 16S rRNA gene loci of Acanthamoeba spp. possess different unique characteristics usable for the genotyping analyses, and those specific features could contribute to the establishment of molecular taxonomy for the species complex of Acanthamoeba.

• Parasites, Hosts and Diseases
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• v.55 no.6
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• pp.623-630
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• 2017

Plasmodium lactate dehydrogenase (pLDH) is a strong target antigen for the determination of infection with Plasmodium species specifically. However, a more effective antibody is needed because of the low sensitivity of the current antibody in many immunological diagnostic assays. In this study, recombinant Plasmodium vivax LDH (PvLDH) was experimentally constructed and expressed as a native antigen to develop an effective P. vivax-specific monoclonal antibody (mAb). Two mAbs (2CF5 and 1G10) were tested using ELISA and immunofluorescence assays (IFA), as both demonstrated reactivity against pLDH antigen. Of the 2 antibodies, 2CF5 was not able to detect P. falciparum, suggesting that it might possess P. vivax-specificity. The detection limit for a pair of 2 mAbs-linked sandwich ELISA was 31.3 ng/ml of the recombinant antigen. The P. vivax-specific performance of mAbs-linked ELISA was confirmed by in vitro-cultured P. falciparum and P. vivax-infected patient blood samples. In conclusion, the 2 new antibodies possessed the potential to detect P. vivax and will be useful in immunoassay.

• Journal of Dairy Science and Biotechnology
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• v.29 no.1
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• pp.49-54
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• 2011

Bile salt hydrolase (BSH, EC 3.5.1.24) activity, which cleaves amide bond between carboxyl group (bile acid) and amino group (glycine or taurine), is commonly detected in gut-associated species of human and animal. During the screening of BSH active strains from the fecal samples of elderly human volunteers, strain CU30-2 was isolated on the basis of the highly active BSH producing activity. A bsh gene of the isolate was cloned into the pET22b expression vector and overexpressed in Escherichia coli BL21 (DE3) Gold by induction with 1mM IPTG. The overexpressed BSH enzyme with 6x His-tag was purified with apparent homogeneity using a $Ni^+$-NTA agarose column and characterized. The BSH enzyme of E. faecalis CU30-2 exhibited approximately 50 times higher activity against glycol-conjugated bile salts than tauro-conjugated bile salts having the highest activity against glycocholic acid. Considering the prevalence of E. faecalis strains in the human GI tract and glycol-conjugates dominated bile acid composition of human bile, further study is needed to investigate the impact of the BSH activity exerted by E. faecalis strains to the host as well as to the BSH producing strains.

• Development and Reproduction
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• v.8 no.1
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• pp.19-25
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• 2004

Pax6, a member of the highly conserved homeobox gene family, is known to be expressed in spatially and temporally restricted pattern during embryogenesis. To examine the spatial expression pattern of Pax6 in malaria vector mosquito Anopheles stephemi, in different molecular environment, the germ line transformation technique using piggyBac transposon combined with the use of Pax6 specific 3xp3-EGFP marker was utilized. Four transgenic lines with a transformation rate of 6.7% were established. Transgenes were stably expressed in subsequent several generations. The transgenic lines showed 3 different expression pattern with spatial specificity, possibly due to enhancing and/or silencing position effects. In two transgenic lines, noble expression pattern of Pax6 was observed in the region that has not been previously reported in any animal species. The results show that the tranposon piggyBac mediated germ line transformation system can be used as an efficient tool for the generation of diverse spatially restricted reporter gene expression.