• Journal of the Korean Wood Science and Technology
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• 제26권3호
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• pp.63-72
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• 1998

In order to evaluate the biodegradability and mechanism of 4,5,6-trichloroguaiacol (TCG) produced from bleaching process in pulp mill by Phanerochaete chrysosporium, Trametes versicolor, and Inonotus cuticularis, changes in TCG and its metabolites during biodegradation were analyzed by HPLC, and GC/MS spectrometry. By three fungi, the maximum biodegradability against TCG were very quickly reached, compared with other chlorinated aromatic compounds such as PCP. Within 24 hrs, T versicolor indicated up to 95% of TCG removal rate, and P. chrysosporium and I. cuticularis also showed more than 80%, and 90%, respectively. Particularly, in case of T. versicolor, the removal rate of TCG after 1 hr. incubation was reached to approximately 90%, implying very rapid metabolization of TCG. However, by analyzing the filtrates extracted from TCG containing culture by GC/MS, the major metabolites at initial stage of biodegradation were dimers, indicating that the added TCG monomers were quickly polymerized. The others were trichloroveratrole, dichloroguaiacol, and trichlorobenzoic acid, suggesting that TCG may be biodegraded by several sequential reactions such as polymerization, oxidation, methylation, dechlorination, and hydroxylation. In other experiments, the extracellular fluid which did not contain any fungal mycelia was used to evaluate the effect of mycelia on TCG biodegradation. The extracellular fluid of T. versicolor also biodegraded TCG up to 90% within 24hrs, but those of P. chrysosporium and I. cuticularis did not show any good biodegradability. T versicolor showed the highest value of laccase, and other two fungi indicated a little activity of lignin peroxidase (LiP) and manganese peroxidase (MnP). In addition, the laccase activity of T. versicolor was very linearly proportional to the removal rate of TCG during incubation, in other words, showing the induction effect against TCG. Consequently, the biodegradation of TCG was very dependent upon the activity of laccase.

• 생명과학회지
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• 제6권2호
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• pp.142-148
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• 1996

Aloe(Aloe arborescens M$_{ILL}$) has been used as a home medicine for the past several thousand in the world, and has been studied on anti-bacterial and anti-fungal activities, hypotension, atherosclerosis, myocardiac infartion, apoplexy, diabetes as a chronic digenerative disease, tumors, gastrointestinal tract, liver and pancreas' diseases, and genitourinary tract etc. SAMP8 as a learing and memory impairment animal model were fed basic and/or experimental diets with 1.0% freezing dried(FD)-aloe for 8 months. The passive avoidance tests such as acqusition trial and retention test were significantly higher in aloe group than in control group. Grading score of senescence resulted in a marked decreases in aloe group compared with control group. Acetylcholinesterase(AChE) activity was remarkably increased in aloe group compared with control group. Neurotransmitters such as dopamine(DA) and serotonin(5-HT) almost did not change by the feeding of aloe-added diet, but their metabolites such as homovanillic acid(HVA) and 5-hydroxy-indole acetic acid(5-HIAA) in aloe group were significantly increased compared with control group. Therefore, the ratios of HVA/DA and 5-HIAA/5-HT as a ratio of metabolite on neurotransmitter were significantly increased by the feeding of aloe-added diet. These results suggest that aloe vara may be activated acetylcholinesterase, the metabolite of neurotransmitter, and ratios of metabolite on neurotransmitter, resulting ina greater prevention of learning and memory impairments such as Alzheimertype dementia.

• Molecules and Cells
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• 제42권4호
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• pp.363-375
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• 2019

Fungal sectorization is a complex trait that is still not fully understood. The unique phenotypic changes in sporadic sectorization in mutants of CpBck1, a mitogen-activated protein kinase kinase kinase (MAPKKK) gene, and CpSlt2, a mitogen-activated protein kinase (MAPK) gene, in the cell wall integrity pathway of the chestnut blight fungus Cryphonectria parasitica have been previously studied. Although several environmental and physiological factors cause this sectoring phenotype, genetic variants can also impact this complex morphogenesis. Therefore, RNA sequencing analysis was employed to identify candidate genes associated with sectorization traits and understand the genetic mechanism of this phenotype. Transcriptomic analysis of CpBck1 and CpSlt2 mutants and their sectored progeny strains revealed a number of differentially expressed genes (DEGs) related to various cellular processes. Approximately 70% of DEGs were common between the wild-type and each of CpBck1 and CpSlt2 mutants, indicating that CpBck1 and CpSlt2 are components of the same MAPK pathway, but each component governs specific sets of genes. Functional description of the DEGs between the parental mutants and their sectored progenies revealed several key pathways, including the biosynthesis of secondary metabolites, translation, amino acid metabolism, and carbohydrate metabolism; among these, pathways for secondary metabolism and translation appeared to be the most common pathway. The results of this comparative study provide a better understanding of the genetic regulation of sector formation and suggest that complex several regulatory pathways result in interplays between secondary metabolites and morphogenesis.

• 한국미생물·생명공학회지
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• 제50권4호
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• pp.488-500
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• 2022

Most fungal infections by opportunistic yeast pathogens such as Candida spp. are the major causes of morbidity and mortality in patients with lowered immune. Previous studies have reported that some strains of Candida secret secondary metabolites play an important role in the decreasing of immunity in the infected patient. In this study, 110 Candida spp. were isolated from different clinical specimens from Baghdad hospitals. Candida isolates were identified by conventional methods, they were processed for Candida speciation on CHROMagar. The results of identification were confirmed by internal transcribed spacer (ITS) sequencing. Phylogenetic trees were analyzed with reference strains deposited in GenBank. Antifungal susceptibility testing was evaluated by the disc diffusion method and performed as recommended by the Clinical and Laboratory Standard Institute (CLSI) M44-A document. Candida isolates investigated produce secondary metabolites gliotoxin with HPLC technique and quantification. Out of 110 Candida isolates, C. albicans (66.36%) was the most frequent isolate, followed by the isolates of C. tropicalis (10.9%) and C. glabrata (6.36%) respectively. Concerning the antifungal susceptibility test, Candida isolates showed a high level of susceptibility to Miconazole (70.9%), Itraconazole (68.2%), and Nystatine (64.5%). The ability of obtained isolates of Candida spp. to produce gliotoxin on RPMI medium was investigated, only 28 isolates had the ability to secret this toxin in culture filtrates. The highest concentrations were detected in C. albicans (1.048 ㎍/ml). Gliotoxin productivity of other Candida species was significantly lower. The retention time for gliotoxin was approximately 5.08 min.

• Mycobiology
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• 제51권4호
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• pp.246-255
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• 2023

Genus Penicillium comprising the most important and extensively studied fungi has been well-known as a rich source of secondary metabolites. Our study aimed to analyze and investigate biological activities, including in vitro anti-cancer, anti-inflammatory and anti-diabetic properties, of metabolites from a marine-derived fungus belonging to P. levitum. The chemical compounds in the culture broth of P. levitum strain N33.2 were extracted with ethyl acetate. Followingly, chemical analysis of the extract leaded to the isolation of three ergostane-type steroid components, namely cerevisterol (1), ergosterol peroxide (2), and (3β,5α,22E)-ergosta-6,8(14),22-triene-3,5-diol (3). Among these, (3) was the most potent cytotoxic against human cancer cell lines Hep-G2, A549 and MCF-7 with IC₅₀ values of 2.89, 18.51, and 16.47 ㎍/mL, respectively, while the compound (1) showed no significant effect against tested cancer cells. Anti-inflammatory properties of purified compounds were evaluated based on NO-production in LPS-induced murine RAW264.7 macrophages. As a result, tested compounds performed diverse inhibitory effects on NO production by the macrophages, with the most significant inhibition rate of 81.37±1.35% at 25 ㎍/mL by the compound (2). Interestingly, compounds (2) and (3) exhibited inhibitory activities against pancreatic lipase and α-glucosidase enzymes in vitro assays. Our study brought out new data concerning the chemical properties and biological activities of isolated steroids from a P. levitum fungus.

• 한국환경과학회지
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• 제27권9호
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• pp.771-780
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• 2018

To develope a microbial weed control agent, HCN-producing bacteria were isolated, and their characteristics were investigated. A selected strain of WA15 was identified as Pseudomonas koreensis by morphological, cultural, biochemical and 16S rRNA gene analyses. The conditions for HCN production was investigated by a One-Variable-at-a-Time (OVT) method. The optimal HCN production conditions were tryptone 1%, glycine 0.06%, NaCl 1%, and an initial pH and temperature of 5.0 and $30^{\circ}C$, respectively. The major component for HCN production was glycine. Under optimal conditions, HCN production was about 3 times higher than that of the basal medium. The WA15 strain had physiological activities, such as indoleacetic acid that was associated with the elongation of plant roots and siderophore and ammonification inhibiting fungal growth, and produced hydrolytic enzymes, such as cellulase, pectinase and lipase. The strain was able to inhibit the growth of phytopathogenic fungi, such as Rhizoctonia solani, Botrytis cinerea and Fusarium oxysporum, by the synergistic action of volatile HCN and diffusible antimicrobial compounds. A microscopic observation of R. solani that was teated with the WA15 strain showed morphological abnormalities of fungal mycelia, which could explain the role of the antimicrobial metabolites that were produced by the WA15 strain. The volatile HCN produced by the WA15 strain was also found to have insecticidal activity against termites. Our results indicate that Pseudomonas koreensis WA15 can be applied as a microbial agent for weed control and also as a termite repellent. Furthermore, it could be applied as a microbial termiticidal agent to replace synthetic insecticides.

• The Plant Pathology Journal
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• 제19권2호
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• pp.85-91
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• 2003

Pre-treatment with DL-3-aminobutyric acid (BABA) in the cucumber plants caused the decrease of disease severity after inoculation with anthracnose pathogen Colletotrichum orbiculare. In this study, ultrastructures of the vascular bundle and the infection structures in the leaves of BABA-treated as well as untreated cucumber plants were observed after inoculation with the anthracnose pathogen by electron microscopy. The ultrastructures of vascular bundle in the leaves of BABA-treated plants were similar to those of the untreated plants except plasmodesmata. In the BABA-treated plants, the plasmodesmata were more numerous than in the untreated plants, suggesting that the BABA treatment may cause the active transfer of metabolites through the vascular bundle. In the leaves of untreated plants, the fungal hyphae were spread widely in the plant tissues at 5 days after pathogen inoculation. Most cellular organelles in the hyphae were intact, indicating a compatible interaction between the plant and the parasite. In contrast, in the leaves of BABA pre-treated plants the growth of most hyphae was restricted to the epidermal cell layer at 5 days after inoculation. Most hyphae cytoplasm and nucleoplasm was electron dense or the intracellular organelles were degenerated. The cell walls of some plant cells became thick at the site adjacent to the intercellular hyphae, indicating a mechanical defense reaction of the plant cells against the fungal attack. Furthermore, hypersensitive reaction (HR) of the epidermal cells was often observed, in which the intracellular hyphae were degenerated. Based on these results it is suggested that BABA causes the enhancement of defense mechanisms in the cucumber plants such as cell wall apposition or HR against the invasion of C. orbiculare.

• Journal of Microbiology and Biotechnology
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• 제19권6호
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• pp.560-565
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• 2009

We isolated nine endophytic fungi from the roots of salt-stressed soybean cultivar Daewonkong and screened them for growth-promoting secondary metabolites. Of all fungal isolates, P-4-3 induced maximum growth promotion of waito-c rice and soybean. Analysis of the culture filtrate of P-4-3 showed the presence of physiologically active gibberellins $GA_1$, $GA_3$, $GA_4$, and $GA_7$, along with physiologically inactive $GA_{15}$ and $GA_{24}$. The plant growth promotion and gibberellin-producing capacity of P-4-3 was much higher than wild-type Gibberella fujikuroi, which was taken as the control during the present study. The fungal isolate P-4-3 was identified as a new strain of Scolecobasidium tshawytschae through the morphological characteristics and phylogenetic analysis of 18S rDNA sequence. Gibberellins production and plant growth promoting ability of genus Scolecobasidium was reported for the first time in the present study.

• Journal of Microbiology and Biotechnology
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• 제20권12호
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• pp.1744-1749
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• 2010

The role of endophytic fungi in plant growth and development is well documented. However, endophytic fungi with growth promotion capacity have never been isolated from weeds previously. In the current study, we isolated 8 fungal endophytes from the roots of Monochoria vaginalis, a serious weed of rice paddy in Korea. These isolates were screened on Waito-C, in order to identify plant growth promoting metabolites. Two fungal isolates (M5.A & M1.5) significantly promoted the plant height and shoot length of Waito-C during preliminary screening experiments. The culture filtrates (CFs) of M5.A and M1.5 also promoted the shoot length of Echinocloa crusgalli. Gibberellins (GAs) analysis of the CFs of M5.A and M1.5 showed that these endophytic fungi secrete higher quantities of GAs as compared with wild-type G. fujikuroi KCCM12329. The CF of M5.A contained bioactive GAs ($GA_3$, 2.8 ng/ml; $GA_4$, 2.6 ng/ml, and $GA_7$, 6.68 ng/ml) in conjunction with physiologically inactive $GA_9$ (1.61 ng/ml) and $GA_{24}$ (0.18 ng/ml). The CF of M1.5 contained physiologically active GAs ($GA_3$, 1.64 ng/ml; $GA_4$, 1.37 ng/ml and $GA_7$, 6.29 ng/ml) in conjunction with physiologically inactive $GA_9$ (3.44 ng/ml), $GA_{12}$ (0.3 ng/ml), and $GA_{24}$ (0.59 ng/ml). M5.A and M1.5 were identified as new strains of Penicillium sp. and Aspergillus sp., respectively, based on their 18S rDNA sequence homology and phylogenetic analysis.

• 미생물학회지
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• 제55권2호
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• pp.157-159
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• 2019

낙동강 주변에서 채취한 토양으로부터 분리한 Pseudomonas fluorescens NBC275 (Pf275) 균주는 식물과 곤충에 병을 일으키는 곰팡이류에 우수한 항균력을 보였다. 본 연구에서는 Pf275 균주의 전체염기서열을 해독하고 분석하였는데, 총 염기서열은 6,610,362 bp였고, GC 함량은 60.9%였다. 염색체는 5,869개의 단백질을 암호화하였고, 16개의 rRNA와 65개의 tRNA로 구성되어 있었다. 유전체의 분석을 통해 항균력을 나타내는 2차 대사산물을 암호화하는 유전자를 확인할 수 있었는데, Pf275 균주는 pyoverdine, 2, 4-diacetylphloroglucinol 및 phenazine 등의 항균물질을 생산하였고, 이들 대사산물에 의해 항균력 및 생물방제효과를 나타내는 것으로 판단된다.