• Journal of Microbiology
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• v.40 no.3
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• pp.199-204
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• 2002

A microsporidium, from cabbage white bntteflies, Pieris rapae, collected in Korea, was purified and characterized according to its gene structure, spore morphology and pathogenicity. From the observation of the isolate by SEM and TEM, the endospores, exospores and nuclei, about 12 polar filament coils of the polar tube and posterior vacuoles were all identified. The nucleotide sequence was determined for a portion of genomic DNA which spans the V4 variable region of the small subunit rRNA gene. Comparison with the GenBank database for 15 other microsporidia species suggests that this isolate is most closely related to Nosema species. The pathogenicity against cabbage white butterflies was quantified by inoculating variable doses of spores to the second instar larvae. Peroral inoculation at a dosage of 10$\^$8/ spores/ml resulted in the death of all larvae prior to adult eclosion, but at lower spore dosages of 10$\^$4/-10$\^$5/ spores/ml, many adults successfully emerged. The median lethal dose (LD$\_$50/) was deter-mined to be 4.6$\times$10$\^$6/ spores/ml and the isolate also transmitted transovarially to the progeny eggs at a frequency of 92%.

• Korean Journal of Plant Taxonomy
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• v.38 no.4
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• pp.459-476
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• 2008

Taxonomic characteristics of spores of 17 species belonging to 6 genera of the Korean Thelypteridaceae are examined. Description of each species and key to the species are provided. Spores of Korean Thelypteridaceae are monad and monolete with bilateral symmetry. Perispore, the sporoderm of spore, was found in all the species examined. The perispores and exospores of Thelypteris japonica var. japonica, T. japonica var. glabrata and Pseudocyclosorus subochthodes are much similar to each other, but the rest of taxa examined shows diverse patterns of the surface ornamentation of perispores and exopores enough to distinguish genera and sometimes to distinguish species in some genera. Previous study reported that perispore is not easily distinguished from exospore in Cyclosorus and Leptogramma. However, three species of Cyclosorus examined here show different pattern having scabrate or verrucate exospores and cristate or echinate perispores. Leptogramma pozoi ssp. mollisima also have echinate perispore and fossulate exospore. Macrothelypteris oligophlebia var. elegans and M. viridifrons have scabrate exospore which is contrast to previous report of reticulate exospore. Thelypteris glanduligera, T. angustifrons and T. laxa show same patterns of perispore and exospore with reticulate perispore and fossulate exospore and hence cannot be distinguished by spores only.

• Microbiology and Biotechnology Letters
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• v.25 no.2
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• pp.159-165
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• 1997

We collected 3,237 plant samples, mainly leaves of various trees, from many provinces in Korea and a total of 1,925 Bacillus thuringiensis isolates were obtained and characterized. The isolates were characterized in terms of crystal morphology, PAGE pattern of the toxin proteins, plasmids pattern, biochemical characteristics, and bioassay. The microscopic observation showed that 49.1% of the isolates have bipyramidal shape crystals, 7.1% of spherical shape crystals, 1.4% of rhomboidal shape crystals, and others have small or amorphous inclusions. The insecticidal activities of the spore-crystal mixtures of isolates were tested against Plutella xylostella, Bombyx mori, Culex pipiens, and Agelastica coerulea. Bioassay showed that 51.3% of the isolates were shown to be active; lepidopteran-specific (44.8%), dipteran-specific(4.9%) and coleopteran-specific (1.6%). The remainder(48.8%) did not show any activity against the insects we tested. Interestingly though, some of these non-active isolates were shown to have bipyramidal crystals. By serotyping 22 isolates of our collection, we found that there are various kind of subspecies such as aizawai, amagiens, canadensis, darmstadiensis, galleriae, finitimus, kurstaki, morrisoni and neoleonensis, and three isolates have been classified into a new serotype, H49, and one of them, the type strain, named subsp. muju. From this study it was found that phylloplane is a good source for the isolation of Bacillius thuringiensis, and Bacillus thuringiensis is distributed widely in Korea.

• Research in Plant Disease
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• v.10 no.2
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• pp.130-134
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• 2004

The pathogenesity of 25 isolates of Colletotrichum gloeosporioides from apple, 42 isolates from pepper, 5 isolates from jujube, 8 isolates from persimmon was evaluated to know transmission to strawberry from other infected plants. Followings are the results. Colony morphology and spore size on potato dextrose agar was similar. When each isolate was inoculated on leaf and petiole of strawberry, isolates from persimmon was the most pathogenic. Five isolates, one pathogenic isolate per each host, were evaluated in simulated field condition under natural rainfall for their natural infectivity. All isolates infected strawberry in field condition, so C. gloeosporioides from other hosts are potential inoculum source of strawberry anthracnose.

• Journal of fish pathology
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• v.16 no.1
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• pp.23-30
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• 2003

On September in 1998, a microsporidian infection was recognized in ayu, Plecoglossus altivelis, farmed on Kyongnam province of South Korea. Cumulative mortality was around 10% in 10 days. Infected fish which were piping for air near the surface of the water or in the asphyxic, lethargic condition revealed darkening of body and abdominal distention. Numerous whitish nodules up to 3mm in size were observed throughout most of body organs and tissues including gill, operculum, peritoneal wall and organs. Xenomas were also histologically confirmed in multiple internal organs with the evidences suggesting circulatory disturbance. Based on the morphology of spore and xenoma, and the distribution of xenomas in organs and tissues, this disease was diagnosed to be a microsporidiosis caused by Glugea plecoglossi. The mortality might be deeply related to the local circulatory disturbance by xemonas rather than the mechano-chemical effect of xenomas on adjacent tissues.

• ALGAE
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• v.18 no.4
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• pp.239-253
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• 2003

The morphotaxonomic characters of the genus Spirogyra were investigated to clarify their taxonomic category and the variation range among species on the basis of comparative morphological and numerical analyses by unialgal cultures and field samples collected from various freshwater habitats in Korea. 25 characters selected on morphological feature of the species were examined on 568 individuals for morphological comparisons and numerical analyses. Width, length and their length/width ratio of vegetative cell, shape of septum, chloroplast number, maximum width, width, length and their length/width ratio of female gametangium, length of male gametangium, size and shape of zygospore, and cell wall ornamentation of the spore showed a comparatively high vector in principal component analysis. In cluster analysis, 15 taxa analysed were divided into 8 major groups by the average taxonomic distance 1.0 level. Considering the morphology and numerical analysis, Spirogyra crassoidea could not be recognized as an independent species, therefore it was treated as a variety of S. ellipsospora. S. koreana (nom. invalidum), recognized as a new taxon, is under the investigation for its clear taxonomic category.

• Korean Journal of Plant Taxonomy
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• v.45 no.4
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• pp.299-305
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• 2015

A comparison of the external morphology and spores clearly distinguished Huperzia lucidula (Michaux) Trevis. in northeast Asia and North America in terms of leaf shape, leaf margin, distribution of stomata on leaves, and spore shape. Therefore, the northeast Asian plants should be treated as a separate species, H. asiatica (Ching) B.-Y. Sun & J. Lim. In addition, we believe that H. javanica (Sw.) C. Yang, regarded as conspecific or infraspecific with H. serrata (Thunb.) Trevis., is a distinct species based on the presence of a leaf petiole and serrated leaf margins, and the shape of the gemmiferous branchlets.

• Journal of Microbiology
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• v.45 no.3
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• pp.262-267
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• 2007

During a screening program, an actinomycete strain isolated from the Egyptian soil was investigated for its potential to show antimicrobial activity. The identification of this isolate was performed according to spore morphology and cell wall chemo-type, which suggested that this strain is a streptomycete. Further cultural, physiological characteristics and the analysis of the nucleotide sequence of the 16S rRNA gene (1480 bp) of this isolate indicated that this strain is identical to Streptomyces violaceusniger (accession number EF063682) and then designated S. violaceusniger strain HAL64. In its culture supernatant, this organism could produce one major compound strongly inhibits the growth of Gram-positive but the inhibition of Gram-negative indicator bacteria was lower. The antibiotic was separated by silica gel column chromatography and then purified on a sephadex LH-20 column and finally the purity was checked by HPLC. The chemical structure of the purified compound was determined using spectroscopic analyses (molecular formula of $C_{33}H_{32}N_{2}O_{10}$ and molecular weight of 617.21) and found to be identical to the kosinostatin, a quinocycline antibiotic which is known to be produced by Micromonspora sp. TP-A0468 (Igarashi et al., 2002) and to quinocycline B isolated from Streptomyces aureofaciens (Celmer et al., 1958). Although the antibiotic is known, the newly isolated strain was able to produce the antibiotic as a major product providing an important biotechnological downstream advantage.

• The Korean Journal of Mycology
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• v.42 no.4
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• pp.306-311
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• 2014

In this study, arbuscular mycorrhizal fungi (AMF) were isolated and cultivated from rhizospheres of various plants in Korea. Five species belonging to four genus were identified based on spore morphology and 18S rDNA sequence analysis: Acaulospora cavernata Claroideoglomus luteum, Diversispora aurantium, D. trimurales, Rhizophagus irregularis. These fungal species have not been cultivated or reported to date in Korea, Morphological description and phylogenetic analysis for each species were presented. This result could be useful for research of AMF diversity in Korea.

• Mycobiology
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• v.44 no.4
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• pp.237-247
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• 2016

Aspergillus (Trichocomaceae, Eurotiales, and Ascomycota) is a genus of well-defined asexual spore-forming fungi that produce valuable compounds such as secondary metabolites and enzymes; however, some species are also responsible for diseases in plants and animals, including humans. To date, 26 Aspergillus species have been reported in Korea, with most species located in terrestrial environments. In our study, Aspergillus species were isolated from mudflats and sea sand along the western and southern coasts of Korea. A total of 84 strains were isolated and identified as 17 Aspergillus species in 11 sections on the basis of both morphological characteristics and sequence analysis of the calmodulin gene (CaM) locus. Commonly isolated species were A. fumigatus (26 strains), A. sydowii (14 strains), and A. terreus (10 strains). The diversity of Aspergillus species isolated from mudflats (13 species) was higher than the diversity of those from sea sand (five species). Four identified species-A. caesiellus, A. montenegroi, A. rhizopodus, and A. tabacinus-are in the first records in Korea. Here, we provide detailed descriptions of the morphological characteristics of these four species.