• Journal of Microbiology and Biotechnology
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• v.19 no.11
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• pp.1364-1368
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• 2009

Lysosomes, as a cell organelle type, are safe biological control agents that may be possible replacements for chemical antimicrobial agents because they are simply isolated from egg white. In this study, it was found that the lysosomes isolated from egg white exhibited pH-dependent antimicrobial activity, with the optimal activity found at pH 6.0. The efficiency of lysosomes in inhibiting bacterial growth and activity was evaluated over a 12-h treatment period. Seven different microorganisms were used as bacterial strains, and the lysosomes showed a significant antimicrobial effect against all strains. In addition, the antimicrobial activity was maintained for 100 days, and there did not appear to be any resistance of E. coli to the lysosomal activity up to the eighth culture. However, the lysosomes did not affect the viability of mammalian cells, suggesting the biocompatibility of lysosomes. These highly effective lysosomes have a bright future in the application of novel antimicrobial sources as a cell organelle type.

• Integrative Medicine Research
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• v.6 no.1
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• pp.12-18
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• 2017

Cryopreservation is a process that preserves organelles, cells, tissues, or any other biological constructs by cooling the samples to very low temperatures. The responses of living cells to ice formation are of theoretical interest and practical relevance. Stem cells and other viable tissues, which have great potential for use in basic research as well as for many medical applications, cannot be stored with simple cooling or freezing for a long time because ice crystal formation, osmotic shock, and membrane damage during freezing and thawing will cause cell death. The successful cryopreservation of cells and tissues has been gradually increasing in recent years, with the use of cryoprotective agents and temperature control equipment. Continuous understanding of the physical and chemical properties that occur in the freezing and thawing cycle will be necessary for the successful cryopreservation of cells or tissues and their clinical applications. In this review, we briefly address representative cryopreservation processes, such as slow freezing and vitrification, and the available cryoprotective agents. In addition, some adverse effects of cryopreservation are mentioned.

• Korean journal of applied entomology
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• v.43 no.3 s.136
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• pp.233-239
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• 2004

The potential of five entomopathogenic nematodes, Steinernema carpocapsae Pocheon strain, S. logicaudum Nonsan strain, S. glaseri Dongrae strain, Heterorhabditis bacteriophora Hamnyang strain, and Heterorabditis sp. Gyeongsan strain were evaluated as biological control agents against a mushroom fly, Mycophila speyeri in the mushroom, Pleurotus ostreatus cultivation house. Control effect of M. speyeri was significantly different according to nematode species. Heterorhabditis was more effective than Steinernema. H. bacteriophora Hamnyang strain showed the highest control effect representing $49.0\%$ (7 days), $89.5\%$ (14 days) and $89.1\%$ (21 days post-treatment) at the rate of $1\times10^6$ and $46.5\%$ (7 days), $76.6\%$ (14 days) and $85.4\%$ (21 days post-treatment) at the rate of $1.0\times10^5$ Ijs/$1.5 m^2$ in Changnyoung, Gyeongnam, respectively. In Jinju, Gyeongnam, control effects of the sa me species were $54.0\%$ (7 days), $74.5\%$ (14 days), and $79.8\%$ (21 days post-treatment) at the rate of $1\times10^6$ and $49.0\%$ (7 days), $76.6\%$ (14 days), and $61.1\%$ (21 days post-treatment) at the rate of $1.0\times10^5$ Ijs/$1.5 m^2$, respectively.

• Asian Journal of Turfgrass Science
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• v.20 no.2
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• pp.175-190
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• 2006

The term mycoherbicide started in 1970, but its interest heightened due to increase costs of chemical herbicides. A classical biocontrol agent is expected to become a permanent part of its new environment and do no harm to it. Contemporary biological control agent(BCA) must be produced by artificial culture and could be applied like chemical herbicides over weeds. BCA is different from the classical approach in that it released through natural spread. To date 26 species of fungi are used as classical BCA against 26 species of weeds in seven countries. There are a number of examples of pathogens attacking non-target plants. But through risk assessments which include understanding the taxonomy, biology and ecology, the target and non-target species, it will be safe to introduce of exotic pathogens to control weeds. But pathogens have not been successfully used in practice. Many mycoherbicides show potential in laboratories, but are ineffective in the field and not consistent from year to year or field to field. There is also a lack of understanding humidity, dew formation and temperature and their effects on suppression of weeds by plant pathogens. Potential pathogen must be selected as a BCA. Previous studies suggest that these pathogens must (1) produce abundant and durable inoculum in artifical culture, (2) be genetically stable and weed specific and (3) kill weeds in control. A granular preparation of mycoherbicide into sodium alginate is lighter than liquids and less bulky than organic matter. Gel forms have also been used.

• 보존과학연구
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• s.22
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• pp.5-25
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• 2001

The germicidal and insecticidal properties of volatile components extracted from star anise(Illicium verum Hooker filius) and clove (Eugenia caryophyllata THUNBERG)were evaluated against five microorganisms and three insects for the purpose of developing biocidal active substances from medicinal plants. The volatile components of star anise and clove showed strong antimicrobial effect against Aspergillus niger, Penicillium funiculosum, Mucor hiemalis, Trichoderma viride, and Aureobasidium pullulans. The extracts of each medicine also showed insecticidal effects against Sitophilusoryzae L., Lyctus linearis GOZE, and Reticulitermes spertus kyushuensis Morimoto. Fumigant toxicities to adult insects were determined. In the case of fumiganttoxicity, the extract of star anise showed 100% mortality against R. spertus, S.oryzae, and L. linearis at rates of $2.5\mu\ell$, $50\mu\ell$, $250\mu\ell$/filter paper, respectively but showed no killing effects by clove. The volatile components of star anise and clove were investigated by means of GC/MS. The main constitute, anethole among 20components from star anise and eugenol among 9 components from clove were identified. The mixture of star anise and clove as the volume ratio of 2 : 1 showed higher properties for antimicrobial and insecticidal effect than each volatile component. A. niger was inhibited by the mixture(125ml/$m^3$) for up to 10 days of exposure. Also, from the result of observing state change of organic materials by volatile extracts of star anise and clove, volatile extracts effects have no effect on natural organic materials of organic cultural properties and can be used as biological control agent. As research contents as above, the insecticidal and germicidal agents from star anise and clove and the mixture of them were more efficient and high level to prevent biological damage for conservation of organic cultural properties. So they may be used in new development of biologicalinsecticidal and germicidal agents for conservation of cultural properties.

• Research in Plant Disease
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• v.24 no.1
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• pp.41-51
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• 2018

Since fire blight disease on apple and pear was produced in Korea in 2015, there were no registered chemicals to control against this disease. Instead, several antibacterial chemicals that were registered for other bacterial diseases such as soft rot and bacterial spot have been authorized by Rural Development Administration (RDA). However, these chemicals are not tested efficacy for fire blight disease except damage by those treatments on apple and pear in Korea. Thus, we evaluated efficiency using in vitro and in planta assays of antibacterial chemicals such as antibiotics and copper compounds including kasugamycin, oxytetracycline, oxolinic acid and streptomycin, and copper hydroxide, copper sulfate, oxine copper and tribasic copper sulfate, respectively. We also tested two kinds of biological agents. As expected, significant antibacterial effect was observed in vitro test of both antibiotics and copper-based chemicals. In planta test based on disease severity including ooze and water-soaked formation on immature pears, bacterial populations on blooms, and blight lesion formation in artificially inoculated shoots, kasugamycin, oxytetracycline and streptomycin have been shown the most efficiency among tested antibiotics. Four copper-based chemicals tested in this study, control effects are little bit lower than agricultural antibiotics but they seem to be available to use in terms of winter season. Biocontrol agents were also shown possibility to treat in eco-friendly farms. In addition, there are no antibiotic resistance genes in Korean isolates against antibiotics, which were selected for suppression of fire blight in this study.

• Mycobiology
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• v.46 no.2
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• pp.85-91
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• 2018

Endophytic fungi strains (n = 81) were isolated from the leaves, barks, and fruits of Camellia oleifera from Hunan province (China) to delineate their species composition and potential as biological control agents of C. oleifera anthracnose. The fungi were identified by morphological and phylogenetic analyses. Fungal colonization rates of the leaves, barks, and fruits were 58.02, 27.16, and 14.81%, respectively. The isolates were identified as 14 genera, belonging to two subdivisions, Deuteromycotina and Ascomycotina; 87.65% of all isolates belonged to Deuteromycotina. The dominant species, occurring with a high relative frequency, were Pestalotiopsis sp. (14.81%), Penicillium sp. (14.81%), and Fusarium sp. (12.35%). The Simpson's and Shannon's diversity indices revealed the highest species diversity in the leaves, followed by the barks and fruits. The similarity index for the leaves versus barks comparison was the highest, indicating that the number of endophytic fungal species shared by the leaves and barks was higher than barks and fruits or leaves and fruits. Based on the results of dual culture experiments, only five strains exhibited antifungal activity against C. oleifera anthracnose pathogen, with isolate ty-64 (Oidium sp.) generating the broadest inhibition zones. Our results indicate that the endophytes associated with C. oleifera could be employed as natural agents controlling C. oleifera anthracnose.

• The Korean Journal of Mycology
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• v.40 no.1
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• pp.44-48
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• 2012

Ginseng (Panax ginseng) is one of the most widely cultivated medicinal herb in Korea. However, yield losses reached up to 30~60 % due to various diseases during 3 or 5 years of ginseng cultivation. Therefore, successful production of ginseng roots depends primarily on the control of diseases. The objective of this study is to select potential multifunctional biocontrol agents from actinomycetes for the control of multiple ginseng diseases as an alternative to fungicides. Ninety three Streptomyces strains were selected and their ability to produce antibiotics, siderophore and lytic enzymes such as protease and cellulose were investigated. Eight of the isolates, strains A75, A501, 515, 523, A704, A1444, A3265 and A3283 produced cellulase and protease. These strains also produced siderophore and showed potent antifungal activity against Botrytis cinerea, Cylindrocarpon destructans, Collectotricum gloeosporioides, Phytophthora capsici and Rhizoctonia solani causing ginseng root rot.

• The Plant Pathology Journal
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• v.39 no.1
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• pp.108-122
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• 2023

Fusarium oxysporum f. sp. lycopersici (Fol) and Fusarium oxysporum f. sp. cubense (Foc), are the causal agent of Fusarium wilt disease of tomato and banana, respectively, and cause significant yield losses worldwide. A cost-effective measure, such as biological control agents, was used as an alternative method to control these pathogens. Therefore, in this study, six isolates of the Streptomyces-like colony were isolated from soils and their antagonistic activity against phytopathogenic fungi and plant growth-promoting (PGP) activity were assessed. The results showed that these isolates could inhibit the mycelial growth of Fol and Foc. Among them, isolate STRM304 showed the highest percentage of mycelial growth reduction and broad-spectrum antagonistic activity against all tested fungi. In the pot experiment study, the culture filtrate of isolates STRM103 and STRM104 significantly decreased disease severity and symptoms in Fol inoculated plants. Similarly, the culture filtrate of the STRM304 isolate significantly reduced the severity of the disease and symptoms of the disease in Foc inoculated plants. The PGP activity test presents PGP activities, such as indole acetic acid production, phosphate solubilization, starch hydrolysis, lignin hydrolysis, and cellulase activity. Interestingly, the application of the culture filtrate from all isolates increased the percentage of tomato seed germination and stimulated the growth of tomato plants and banana seedlings, increasing the elongation of the shoot and the root and shoot and root weight compared to the control treatment. Therefore, the isolate STRM103 and STRM104, and STRM304 could be used as biocontrol and PGP agents for tomato and banana, respectively, in sustainable agriculture.

• The Plant Pathology Journal
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• v.32 no.3
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• pp.273-280
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• 2016

Most biocontrol agents for plant diseases have been isolated from sources such as soils and plants. As an alternative source, we examined the feces of tertiary larvae of the herbivorous rhino beetle, Allomyrina dichotoma for presence of biocontrol-active microbes. The initial screen was performed to detect antifungal activity against two common fungal plant pathogens. The strain with strongest antifungal activity was identified as Bacillus amyloliquefaciens KB3. The inhibitory activity of this strain correlated with lipopeptide productions, including iturin A and surfactin. Production of these surfactants in the KB3 isolate varied with the culture phase and growth medium used. In planta biocontrol activities of cell-free culture filtrates of KB3 were similar to those of the commercial biocontrol agent, B. subtilis QST-713. These results support the presence of microbes with the potential to inhibit fungal growth, such as plant pathogens, in diverse ecological niches.