• Korean journal of applied entomology
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• v.45 no.3 s.144
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• pp.375-380
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• 2006

A solitary endoparasitoid, Cotesia plutellae, parasitizes diamondback moth, Plutellae xylostella. It has been suggested that its antennae are a major sensory organ to search host and recognize host developmental and other physiological condition during parasitization. This research was performed to understand the parasitic behavior of C. plutellae by analyzing sensory types and their numbers on the antennae using scanning electron microscope. There was no significant difference in antennal length in both male and female C. plutellae, in which both sexes had 16 flagellomeres. Three different types of sensilla (trichoid, seta, and placodea sensilla) were located mostly on flagella and analyzed in their density on the different antennomeres. Trichoid sensillum was the major sensory type and showed about 87% density among all sensilla. Both trichoid and placodea types of sensilla exhibited even numbers on all flagellomeres with some decrease at terminal segments. In contrast, seta form of sensilla showed drastic increase in its density at distal part after 9th flagellomere. When distal half of flagellomeres were cut off, the C. plutellae could not parasitize host larvae. Even when only four distal flagellomeres were removed, the parasitism showed only 30%. These results indicate that C. plutellae antennae are required for parasitism and suggest that seta form of sensilla may play significant roles in recognizing host for parasitization.

• Research in Plant Disease
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• v.22 no.3
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• pp.158-167
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• 2016

A pathogen that causes a new disease on green pumpkin in the nursery and the field was characterized and identified. Symptoms of the disease on green pumpkin were water soaking lesions and spots with strong yellow halo on leaf, brown lesion on flower, and yellow spot on fruit. The bacterial isolates from the leaf spot were pathogenic on the 8 curcubitaceae crop plants, green pumpkin, figleaf gourd, wax gourd, young pumpkin, zucchini, cucumber, melon, and oriental melon, whereas they did not cause the disease on sweet pumpkin and watermelon. They were Gram-negative, rod shape with polar flagella, fluorescent on King's B agar and LOPAT group 1a by LOPAT test. Their Biolog substrate utilization patterns were similar to Pseudomonas syringae pv. syringae's in Biolog database. Phylogenetic trees with 16S rRNA gene sequences and multilocus sequence typing (MLST) with nucleotide sequences of 4 housekeeping genes, gapA, gltA, gyrB, rpoD and those of P. syringae complex strains in the Plant Associated and Environmental Microbes Database (PAMDB) showed that the green pumpkin isolates formed in the same clade with P. syringae pv. syringae strains. The clade in MLST tree was in the genomospecies 1 group. The phenotypic and genotypic characteristics suggested that the isolates from green pumpkin lesion were P. syringae pv. syringae.

• Food Science and Biotechnology
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• v.16 no.4
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• pp.515-519
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• 2007

Rapid immunochromatographic assay (ICA) kits were developed using flagella-specific monoclonal antibodies (MAbs) and rabbit polyclonal antibodies for screening Listeria spp. in food. The establishment of different formats, MAb 2B1 as capture antibody and MAb 7A3 or rabbit polyclonal antibodies as detector antibody, was compared. The 2 formats of the ICA kit were shown to have specific reactions with Listeria and no cross-reactivity with any of the non-Listeria including Escherichia coli O157:H7 and Salmonella enteritidis. The detection limits of the ICA kit using the combination of gold-labeled MAb 7A3 and MAb 2B1 showed $1{\times}10^5$ and $1{\times}10^6\;CFU/0.1\;mL$ at 22 and $30^{\circ}C$, respectively. The other format of the ICA kit using the combination of gold-labeled rabbit polyclonal antibodies and MAb 2B1 showed $1{\times}10^6\;CFU/0.1\;mL$ at $22^{\circ}C$ but weak signal at 30 culture. The format utilizing MAb was more sensitive than the one using polyclonal antibodies for capture antibody. Samples contaminated with L. monocytogenes 4b culture (9-10, 5-6, and 1-2 CFU/mL) on pork and pasteurized milk were confirmed as positive results. Current data suggests that this ICA kit is a rapid, simple and effective tool to screen for Listeria spp. in food.

• Applied Biological Chemistry
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• v.50 no.2
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• pp.87-94
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• 2007

A bacterium which has high enzymatic activities such as amylase, cellulase and protease was isolated from Korean traditional soybean food, doenjang. The isolated bacterium was identified to Bacillus subtilis HS25 by the test of morphological and biochemical properties according to Bergey's Manual of Systematic Bacteriology and API 50 CHL kit, and by the 16S rDNA sequence. The isolated B. subtilis HS25 had a potent antibacterial activity against food born causative or pathogenic bacteria. B. subtilis HS25 is endospore forming cell and contained flagella and abundant viscous material at the out layer of cell wall. It was rod type bacterium $(0.5{\sim}0.8{\times}3{\sim}5{\mu}m)$ having biochemical characteristics such as gram staining(+), catalase(+), oxidase(-) and hydrolysis of esculin(+). The optimal medium compositions for production of antibacterial substance in the B. subtilis HS25 were 1% of soluble starch, 0.5% of yeast extract, 0.5% of peptone and 0.05% of MgCl$_2{\cdot}6H_{2}O$. The optimum temperature and pH of the growth of the B. subtilis HS25 was 35$^{\circ}C$ and pH 7.5, respectively. The antibacterial activity was more high in neutral to a little alkaline pH (6.5-10.5) than in acidic pH. The optimal shaking speed to grow and to produce antibacterial substance of the B. subtilis HS25 was 160${\sim}$200 rpm. The optimal culture time for antibacterial activities of the bacterium were shown to be in the range of 12-36 hr.

• Journal of the Korean Society of Food Science and Nutrition
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• v.34 no.8
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• pp.1251-1257
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• 2005

This study was carried out to investigate characteristics of acetic acid bacteria for persimmon vinegar fermen-tation. Acetic acid bacteria were isolated from statically fermented vinegar. Microscopically the cells appeared as non-motile and non-flagellated, preferentially occuring in pairs. Isolated strains were able to grow in the presence of acetic acid, ethanol, and glucose. Four of them produced 2-ketogluconic acid but did not produce 5-ketogluconic acid. The four strains isolated from statically fermented vinegar were considered to be grouped into Acetobacter. The strains were inoculated into persimmon juice for persimmon vinegar fermentation. They produced acetic acid in the range of 5.25$\∼$5.68$\%$.

• Food Science and Preservation
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• v.14 no.2
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• pp.194-200
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• 2007

In order to enhance the functionality and storage period of traditional fermented foods, the strain CH-14, which To enhance the quality of traditional fermented foods, and to lengthen acceptable storage periods, a bacterial strain, CH-14, showing potent enzyme activities and antibacterial capabilities, was isolated and characterize4 The bacterium wn Gram-positive, catalase-positive, oxidase-negative, formed endospores, expressed flagella, was rod-shaped, and had dimensions of 0.5 0.7m and 3.5 4.2m. The bacterium CH-14 was identified as Bacillus subtilis using Bergey's Manual of Systematic Bacteriology, Bergey's Manual of Determinative Bacteriology, and an API 50 CHL Carbohydrate Test Kit. An optimum growth medium contained 2% (w/v) cellobiose as a carbon source, a mixture of 0.5% (w/v) yeast extract and 0.5% (w/v) peptone as nitrogen sources, and 0.05% (w/v) $MgSO_4{\cdot}7H_2O$. The optimal culture temperature and the optimal initial pH were in the ranges of 30 $45^{\circ}C$ and 4.5 10.0, respectively. Maximum production of the antibacterial substance occurred after 24h of culture. The minimum inhibitory concentrations of the antibacterial substance were 5mg bacterial dry weight/mL against E. coli and P. mirabilis, and 10 mg/mL against S. aureus, S. enteritidis and V. parahaemolyticus.

• Korean Journal of Microbiology
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• v.54 no.4
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• pp.448-452
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• 2018

The full genome sequence of Bacillus safensis KCTC 12796BP which had been isolated from the marine sponge in the seawater of Jeju Island, was determined by Pac-Bio next-generation sequencing system. A circular chromosome in the length of 3,935,874 bp was obtained in addition to a circular form of plasmid having 36,690 bp. The G + C content of chromosome was 41.4%, and that of plasmid was 37.3%. The number of deduced CDSs in the chromosome was 3,980, whereas 36 CDS regions were determined in a plasmid. Among the deduced CDSs in chromosome, 81 tRNA genes and 24 rRNA genes in addition to one tmRNA were allocated. More than 30 CDSs for sporulation, 16 CDSs for spore coat, and 20 CDSs for germination were also assigned in the chromosome. Several genes for capsular polysaccharide biosynthesis and for flagella biosynthesis and chemotaxis in addition to genes for osmotic tolerance through glycine-choline betaine pathway were also identified. Above all, the biosynthetic gene cluster for anti-allergic compounds seongsanamides were found among two non-ribosomal peptide synthetase (NRPS) gene clusters for secondary metabolites.

• Research in Plant Disease
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• v.27 no.4
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• pp.180-186
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• 2021

Typical bacterial symptoms, water-soaking brown and black leaf spots with yellow halo, were observed on watermelon seedlings in nursery and field of Gyeongnam and Jeonnam provinces. Bacterial isolates from the lesion showed strong pathogenicity on watermelon and zucchini. One of them was rod-shaped with 4 polar flagella by observation of transmission electron microscopy. They belonged to LOPAT group 1. The phylogenical trees with nucleotide sequences of 16S rRNA and multi-locus sequencing typing with the 4 house-keeping genes (gapA, gltA, gyrB, and rpoD) of the isolates showed they were highly homologous to Pseudomonas syringae pv. syringae and grouped together with them, indicating that they were appeared as P. syringae genomospecies group 1. Morphological, physiological, and genetical characteristics of the isolates suggested they are P. syringae pv. syringae. We believe this is the first report that P. syringae pv. syringae caused leaf spot disease on watermelon in the Republic of Korea.

• Journal of Life Science
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• v.27 no.1
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• pp.100-121
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• 2017

The sexual reproduction of the unicellular green alga Chlamydomonas is reviewed for a comprehensive understanding of the complex processes. The sexual life cycle of C. reinhardtii is distinguished into five main stages: gametogenesis, gamete activation, cell fusion, zygote maturation, and meiosis and germination. Gametogenesis is induced by nitrogen starvation in the environment. C. reinhardtii has two mating types: mating type plus ($mt^+$) and mating type minus ($mt^-$), controlled by a single complex mating type locus ($MT^+$ or $MT^-$) on linkage group VI. In the early gametogenesis agglutinins are synthesized. The $mt^+$ and $mt^-$ agglutinins are encoded by the autosomal genes SAG1 (Sexual AGglutination1) and SAD1 (Sexual ADhesion1), respectively. The agglutinins are responsible for the flagellar adhesion of the two mating type of gametes. The flagellar adhesion initiates a cAMP mediated signal transduction pathways and activates the flagellar tips. In response to the cAMP signal, mating structures between two flagella are activated. The $mt^+$ and $mt^-$ gamete-specific fusion proteins, Fus1 and Hap2/Gcs1, are present on the plasma membrane of the two mating structures. Contact of the two mating structures leads to develop a fertilization tubule forming a cytoplasmic bridge between the two gametes. Upon fusion of nuclei and chloroplasts of $mt^+$ and $mt^-$ cells, the zygotes become zygospores. It is notable that the young zygote shows uniparental inheritance of chloroplast DNA from the $mt^+$ parent and mitochondrial DNA from the $mt^-$ parent. Under the favorable conditions, the zygospores divide meiotically and germinate and then new haploid progenies, vegetative cells, are released.

• Korean Journal of Microbiology
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• v.52 no.3
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• pp.319-326
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• 2016

An antimicrobial bacterium to pathogenic microorganisms, strain $W5-1^T$ was isolated from Korean fermented-food Kimchi. The isolate was Gram-staining-variable, strictly aerobic, rod-shaped, endospore-forming, and motile with peritrichous flagella. It grew at $15-40^{\circ}C$, at pH 6.0-10.0, and in the presence of 0-4% NaCl. Strain $W5-1^T$ could hydrolyze esculin and xylan, and assimilate $\small{D}$-mannose, but not $\small{D}$-mannitol. Strain $W5-1^T$ showed antimicrobial activity against Listeria monocytogens, Pseudomonas aeruginosa, Staphylococcus aureus, and Salmonella typhi. The G+C content of the DNA of strains $W5-1^T$ was 52.6 mol%. The predominant respiratory quinone was menaquinone-7 (MK-7) and the major cellular fatty acids were $C_{16:0}$, antieiso-$C_{15:0}$, $C_{18:0}$, and $C_{12:0}$. The strain contained meso-diaminopimelic acid in cell-wall peptidoglycan. On the basis of 16S rRNA gene sequence and phylogenetic analysis, the strain W5-1 was shown to belong to the family Paenibacillaceae and was most closely related to Paenibacillus pinihumi $S23^T$ (98.4% similarity) and Paenibacillus tarimensis $SA-7-6^T$ (96.4%). The DNA-DNA relatedness between the isolate and Paenibacillus pinihumi $S23^T$ was 8.5%, indicating that strain $W5-1^T$ represented a species in the genus Paenibacillus. On the basis of the evidence from this polyphasic study, it is proposed that strain $W5-1^T$ is considered to represent a novel species of the genus Paenibacillus, for which the name Paenibacillus kimchicus sp. nov. is proposed. The type strain is $W5-1^T$ (=KACC $15046^T$ = $LMG 25970^T$).