• The Korean Journal of Mycology
• /
• v.52 no.1
• /
• pp.55-60
• /
• 2024

In August 2023, leaf spot disease was observed in peanuts in Cheongju-si, Korea. Leaf spots occurred at the leaf margins and the lesions gradually expanded. Diseased leaf areas were light or dark brown and irregular in shape. A fungal isolate was obtained from symptomatic leaf and cultured on potato dextrose agar (PDA) medium at 25℃. An isolate was identified as Colletotrichum sojae based on morphological characteristics and sequences of the internal transcribed spacers, glyceraldehyde-3-phosphate dehydrogenase, chitin synthase-1, actin, and 𝛽-tubulin genes. Pathogenicity tests were performed on peanut seedlings in a conidial suspension (1×10⁶ conidia/mL). Lesions were observed on the peanut leaf 5 d after inoculation. The pathogen was re-isolated from the lesions of the inoculated leaves. To the best of our knowledge, this is the first report of anthracnose on peanut caused by C. sojae in Korea.

• Korean Journal of Microbiology
• /
• v.49 no.1
• /
• pp.64-70
• /
• 2013

The greenhouse whitefly, Trialeurodes vaporariorum, is an economically important pest for greenhouse crops because they cause direct damage by feeding on plant nutrients and indirect damage as transmits many virus vectors. It has recently become a serious problem because of the continuous use of insecticide resulting in resistance among greenhouse whitefly population. To overcome these problems, in this study, the biological characteristics and virulence of an entomopathogenic fungus isolated from the cadaver of nymph greenhouse whitefly were investigated. Isolated fungus was identified as Isaria fumosorosea by morphological examinations and genetic identification using sequences of the ITS, ${\beta}$-tubulin, and EF1-${\alpha}$ regions. This fungus was named as I. fumosorosea SDTv and tested for the virulence against nymphs T. vaporariorum and the cold activity, the thermotolerance and the stability of UV-B irradiation on conidia. Mortality rate of greenhouse whitefly showed from 84 to 100% and the virulence increased with increasing conidial concentrations, $1{\times}10^5$ to $10^8$ conidia/ml. Conidia were stable at $35^{\circ}C$, 0.1 $J/cm^2$ of UV irradiation and germinated after 8 days at $4^{\circ}C$. Additionally, the activities of chitinases and proteases produced by I. fumosorosea SDTv were varied according to the medium. In conclusion, I. fumosorosea SDTv which showed high mortality rate against greenhouse whitefly will be used effectively in the integrated pest management programs against the greenhouse whitefly.

• Korean Journal of Ecology and Environment
• /
• v.35 no.3 s.99
• /
• pp.198-212
• /
• 2002

A numerical variation and abnormalities were studied on egg bags and embryos of Korean salamander, Hynobius leechii from agricultural habitat. The teratogenic and toxic effects of fungicide benomyl were also investigated with early embryos from non-agricultural habitat. We collected 144 egg bags from agricultural region, and 3418 of early embryos were contained. The lengths of egg bags were varied from 10 to 23 cm and the most frequent length was 19 cm. The number of embryos was varied from 7 to 43, and the most frequent range was 22 to 26. Spontaneous abnormalities were occurred in 406 embryos among 116 egg bags, and 24 kinds of external abnormalities were found. Individuals showing severe external defect were histologically studied and they showed optic dyspalsia, thyroid carcinoma, somatic muscular dysplasia, partial biaxial structure, decrease of red blood cells in the heart, cephalic degeneration and intestinal dysplasia. 385 embryos from non-agricultural region were exposed to 200 nM${\sim}$ 1 ${\mu}$M of benomyl at blastula or gastrula for 12 days. All embryo were dead in the concentration of 1 ${\mu}$M (LD$_{100}$) and 75% of embryos were dead in 800nM of benomyl. Speciflc effect due to benomyl was acrania or cephalic dysplasia and this restult suggests that the benomyl inhibit stongly to the development of neural tissue. These abnormal developments may be caused by antimitotic action, inhibition of tubulin complex, destruction of microtubule, inhibitions of neurulation and closing of neural fold, and by the inhibition of the movement of neural crest cells.

• Korean Journal of Clinical Laboratory Science
• /
• v.52 no.2
• /
• pp.112-118
• /
• 2020

This study was undertaken to examine the effects and to investigate the relevant mechanisms of overexpressing stromal cell-derived factor-1 (SDF-1) produced by engineered mesenchymal stem cells, in a neurogenic bladder (NB) rat model. Sprague-Dawley (SD) rats (N=48) were randomly divided into 4 groups comprising 12 rats each: control group, Injury group, Injury+imMSC group, and Injury+SDF-1 eMSC group. Rats in the Injury+imMSC group were treated with imMSCs, whereas the Injury+SDF-1 eMSC group were administered SDF-1 eMSCs. After 4-weeks therapy, the bladder and pelvic nerve (PN) tissues were examined by subjecting to Masson's trichrome staining and immunofluorescence. Administration of SDF-1 eMSC resulted in improved smooth muscle content in the bladder tissue, significantly increased β-III tubulin expression of the PN, and enhanced SDF-1 expression (P<0.05). The bladder wall repair can be attributed to the overexpression of SDF-1 by SDF-1 eMSCs. Significantly increased SDF-1 expression was obtained in the Injury+SDF-1 eMSC group (P<0.05). The crushed PN also showed significant recovery in the Injury+SDF-1 eMSC group (P<0.05). In conclusion, our results indicate that SDF-1 eMSCs express more SDF-1 in vivo, thereby facilitating the repair of injured nerve and recovery of NB in rats.

• The Korean Journal of Mycology
• /
• v.43 no.3
• /
• pp.200-205
• /
• 2015

Perilla frutescens var. japonica Hara was collected from farmland in Seongju-gun. Fifteen endophytic fungal strains with different colony morphologies were isolated from roots of P. frutescens. Waito-c rice seedlings were treated with the concentrated culture filtrates (CF) of endophytic fungi for observation of their plant growth-promoting activities. In the results, the CF of Y2H001 fungal strain promoted the growth of the waito-c rice seedlings. The phylogenetic tree of Y2H001 strain was analyzed by the combined sequences of the partial internal transcribed spacer region (ITS) and partial betatubulin gene. Molecular and morphological studies identified the Y2H001 strain as belonging to Aspergillus flavus. In gas chromatography mass spectrometry (GC/MS) analysis of the CF of Y2H001 strain, gibberellic acid (GA) was detected and quantified. Therefore, we describe Y2H001 strain as a new $GA_3$-producing A. flavus based on morphological, molecular characteristics and analysis of secondary metabolite.

• Proceedings of the Korean Society of Developmental Biology Conference
• /
• 2003.10a
• /
• pp.101-101
• /
• 2003

Main strategy for a treatment of Parkinson's disease (PD), due to a progressive degeneration of dopaminergic neurons, is a pharmaceutical supplement of dopamine derivatives or ceil replacement therapy. Both of these protocols have pros and cons; former exhibiting a dramatic relief but causing a severe side effects on long-term prescription and latter also having a proven effectiveness but having availability and ethical problems Embryonic stem (ES) cells have several characteristics suitable for this purpose. To investigate a possibility of using ES cells as a carrier of therapeutic gene(s), human ES (hES, MB03) cells were transfected with cDNAs coding for tyrosine hydroxylase (TH) in pcDNA3.1 (+) and the transfectants were selected using neomycin (250 $\mu /ml$). Expression of TH being confirmed, two of the positive clone (MBTH2 & 8) were second transfected with GTP cyclohydrolase 1 (GTPCH 1) in pcDNA3.1 (+)-hyg followed by selection with hygromycin-B (150 $\mu /ml$) and RT-PCR confirmation. By immune-cytochemistry, these genetically modified but undifferentiated dual drug-resistant cells were found to express few of the neuronal markers, such as NF200, $\beta$-tubulin, and MAP2 as well as astroglial marker GFAP. This results suggest that over-production of BH4 by ectopically expressed GTPCH I may be involved in the induction of those markers. Transplantation of the cells into striatum of 6-OHDA- denervated PD animal model relieved symptomatic rotational behaviors of the animals. Immunohistochemical analyses showed the presence of human cells within the striatum of the recipients. These results suggest a possibility of using hES cells as a carrier of therapeutic gene(s).

• Research in Plant Disease
• /
• v.25 no.4
• /
• pp.220-225
• /
• 2019

During the year 2018, the symptoms of bunch rot on Shine Muscat (Vitis vinifera L.) were observed in Kimcheon-si, Gyeongbuk province in Korea. The disease appears on the Shine Muscat as a black rot due to prolific fungal sporulation after it has invaded into the Shine Muscat which look completely empty and dryness. Colonies of these fungi are present on the Shine Muscat skin from fruit setting and increase in amount from early season to harvest, while become peak at ripening stage. To isolate the causal agent, small fragments (2 to 3 mm) of decayed tissue from the lesion margin were placed onto potato dextrose agar (PDA) plates. Fungal colonies on PDA produced dense white aerial mycelium and then covered with dark black conidial heads. These heads were large and radiate, and vesicles were globose (2.12-32.0×2.0-3.1 ㎛). Based on morphological and cultural characteristics, this fungus was identified as Aspergillus tubingensis. To confirm its identity, the internal transcribed spacer, β-tubulin, and RNA polymerase II was sequenced for molecular identification. BLAST search indicated 99% identity with A. tubingensis. The pathogenicity test on healthy grape of Shine Muscat produced bunch rot, as the original symptoms. To select effective fungicides for the control of brunch rot, an in vitro antifungal activity of seven fungicides were evaluated against the growth of A. tubingensis. Five fungicides (dipenoconazole, tebuconazole, metconazole, iminoctadine, and captan) exhibited significantly strong suppression of the mycelial growth of A. tubingensis.

• Parasites, Hosts and Diseases
• /
• v.55 no.2
• /
• pp.207-212
• /
• 2017

Infections of Toxoplasma gondii and Babesia microti are reported in many wild animals worldwide, but information on their incidence and molecular detection in Korean wild fields is limited. In this study, the prevalence of T. gondii and B. microti infection in blood samples of 5 animal species (37 Chinese water deer, 23 raccoon dogs, 6 roe deer, 1 wild boar, and 3 Eurasian badgers) was examined during 2008-2009 in Gangwon-do (Province), the Republic of Korea (=Korea) by using serological and molecular tests. The overall seropositivity of T. gondii was 8.6% (6/70); 10.8% in Chinese water deer, 4.3% in raccoon dogs, and 16.7% in roe deer. PCR revealed only 1 case of T. gondii infection in Chinese water deer, and phylogenic analysis showed that the positive isolate was practically identical to the highly pathogenetic strain type I. In B. microti PCR, the positive rate was 5.7% (4/70), including 2 Chinese water deer and 2 Eurasian badgers. Phylogenetic analysis results of 18S rRNA and the ${\beta}$-tubulin gene showed that all positive isolates were US-type B. microti. To our knowledge, this is the first report of B. microti detected in Chinese water deer and Eurasian badger from Korea. These results indicate a potentially high prevalence of T. gondii and B. microti in wild animals of Gangwon-do, Korea. Furthermore, Chinese water deer might act as a reservoir for parasite infections of domestic animals.

• ALGAE
• /
• v.33 no.1
• /
• pp.1-19
• /
• 2018

Members of the family Parviluciferaceae (Alveolata, Perkinsozoa) are the well-known dinoflagellate parasitoids along with Amoebophrya ceratii species complex and parasitic chytrid Dinomyces arenysensis and contain six species across three genera (i.e., Parvilucifera infectans, P. sinerae, P. rostrata, and P. corolla, Dinovorax pyriformis, and Snorkelia prorocentri) so far. Among Parvilucifera species, the two species, P. infectans and P. sinerae, are very similar or almost identical each other morphologically and genetically, thereby make it difficult to distinguish between the two. The only main difference between the two species known so far is the number of sporangium wall (i.e., 2 layers in P. infectans vs. 3 layers in P. sinerae). During sampling in Masan bay, Korea during the spring season of 2015, the dinoflagellate Akashiwo sanguinea cells infected by the parasite Parvilucifera were observed and this host-parasite system was established in culture. Using this culture, its morphological and ultrastructural features with special emphasis on the variation in the number of sporangium wall over developmental times, were investigated. In addition, the sequences of rDNA regions and ${\beta}-tubulin$ genes were determined. The result clearly demonstrated that the trophocyte at 36 h was covered with 4 layers, and then outer layer of the sporocyte gradually degraded over time, resulting in wall structure consisting of two layers, with even processes being detached from 7-day-old sporangium with smooth surface, indicating that the difference in the number of layers seems not to be an appropriate ultrastructural character for distinguishing P. infectans and P. sinerae. While pairwise comparison of the large subunit rDNA sequences showed 100% identity among P. infectans / P. sinerae species complex, genetic differences were found in the small subunit (SSU) rDNA sequences but the differences were relatively small (11-13 nucleotides) compared with those (190-272 nucleotides) found among the rest of Parvilucifera species (P. rostrata and P. corolla). Those small differences in SSU rDNA sequences of P. infectans / P. sinerae species complex may reflect the variations within inter- strains of the same species from different geographical areas. Taken together, all morphological, ultrastructural, and molecular data from the present study suggest that they are the same species.

• Journal of Microbiology and Biotechnology
• /
• v.30 no.2
• /
• pp.279-286
• /
• 2020

A novel compound named 'kanakugiol' was recently isolated from Lindera erythrocarpa and showed free radical-scavenging and antifungal activities. However, the details of the anti-cancer effect of kanakugiol on breast cancer cells remain unclear. We investigated the effect of kanakugiol on the growth of MCF-7 human breast cancer cells. Kanakugiol affected cell cycle progression, and decreased cell viability in MCF-7 cells in a dose-dependent manner. It also enhanced PARP cleavage (50 kDa), whereas DNA laddering was not induced. FACS analysis with annexin V-FITC/PI staining showed necrosis induction in kanakugiol-treated cells. Caspase-9 cleavage was also induced. Expression of death receptors was not altered. However, Bcl-2 expression was suppressed, and mitochondrial membrane potential collapsed, indicating limited apoptosis induction by kanakugiol. Immunofluorescence analysis using α-tubulin staining revealed mitotic exit without cytokinesis (4N cells with two nuclei) due to kanakugiol treatment, suggesting that mitotic catastrophe may have been induced via microtubule destabilization. Furthermore, cell cycle analysis results also indicated mitotic catastrophe after cell cycle arrest in MCF-7 cells due to kanakugiol treatment. These findings suggest that kanakugiol inhibits cell proliferation and promotes cell death by inducing mitotic catastrophe after cell cycle arrest. Thus, kanakugiol shows potential for use as a drug in the treatment of human breast cancer.