• Title/Summary/Keyword: microbial agents

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Seed Coating for the Application of Biocontrol Agent Bacillus subtilis YBL-7 against Phytopathogens (길항세균 Bacillus subtilis YBL-7 건조포자체의 종자피막화에 의한 생물학적 방제)

  • 장종원;김상달
    • Microbiology and Biotechnology Letters
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    • v.23 no.2
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    • pp.243-248
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    • 1995
  • Agrochemicals for the plant-disease control are criticized severely for causing environmental pollution and residual problems, and consequently microbial disease control agents are expected to be safer and more economical for sustainable agriculture. Treatment of biological control agents to seed requires the use of effective delivery systems that allow full expression of the benefical qualities of the bioprotectant. For the activation and establishment of bioprotectant around the plant seed which are able protect the seeds and seedlings from pathogen attack, the optimal liquid coating formulation was obtained using 2% sodium carboxymethyl cellulose (binder), 20% sesame dregs (solid particulate material), and dried spore of Bacillus subtilis YBL-7 (bioprotectants, 10 mg/g of seed). Suppressive of root rot was demonstrated in pot trials with coated kidney bean (Phaseolus vulgaris L.) seeds. Coated seeds with B. subtilis YBL-7 spore in F. solani-infested soil reduced disease incidence by 85% to 90% after 30 days.

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Compatibility of Entomopathogenic fungus Lecanicillium attenuatum and Pesticides to control Cotton Aphid, Aphis gossypii

  • Kim, Jeong-Jun;Kim, Kyu-Chin
    • International Journal of Industrial Entomology and Biomaterials
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    • v.14 no.2
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    • pp.143-146
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    • 2007
  • Concerns of entomopathogenic fungi as alternative pest control agents are increasing even though chemical pesticides have been used as the main control agents for pests and diseases in crop production. This study was conducted to test the influence of fungicides and insecticides on an isolate of Lecanicillium attenuatum that was reported to have the pathogenicity against cotton aphid, because fungicides and/or insecticides can apply with mycopesticides simultaneous, before and/or after. Fungicides fenbuconazole+thiram and propineb inhibited the spore germination and mycelial growth of L. attenuatum CS625; dimethomorph and procymidone did not affect spore germination or mycelial growth. The insecticide abamectin, deltamethrin, imidachropride, and spinosad had no detrimental effects on spore germination or mycelial growth. Therefore, these results demonstrated that careful selection of pesticides and fungicides can be applied to the integrated pest and disease control with microbial pesticide.

Ambient Air Waste Sorting Facilities Could Be a Source of Antibiotic Resistant Bacteria

  • Calheiros, Ana;Santos, Joana;Ramos, Carla;Vasconcelos, Marta;Fernandes, Paulo
    • Microbiology and Biotechnology Letters
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    • v.49 no.3
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    • pp.367-373
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    • 2021
  • The antimicrobial resistance of Staphylococcus spp. and Gram negative strains present in air samples from waste sorting facilities was assessed. Phenotypic studies have revealed a high percentage of strains of Staphylococcus spp. resistant to methicillin. Genotypically and by RT-PCR, it was found that the mecA gene usually associated with methicillin resistance was present in 8% of the Staphylococcus strains isolated. About 30% of the Gram negative strains from the same samples also displayed resistance to meropenem and 79% of these were resistant to multiple antibiotics from different classes, namely cephalosporins and β-lactams. The results suggest that in professional activities with high levels of exposure to biological agents, the quantification and identification of the microbial flora in the work environment, with the determination of the presence of potential agents displaying multi-resistances is of relevance to the risk assessment. The personal protection of workers is particularly important relevance in these cases, since many of the strains that exhibit multi-resistance are potential opportunistic agents.

New Tool to Simulate Microbial Contamination of on-Farm Produce: Agent-Based Modeling and Simulation (재배단계 농산물의 안전성 모의실험을 위한 개체기반 프로그램 개발)

  • Han, Sanghyun;Lee, Ki-Hoon;Yang, Seong-Gyu;Kim, Hwang-Yong;Kim, Hyun-Ju;Ryu, Jae-Gee
    • Journal of Food Hygiene and Safety
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    • v.32 no.1
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    • pp.8-13
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    • 2017
  • This study was conducted to develop an agent-based computing platform enabling simulation of on-farm produce contamination by enteric foodborne pathogens, which is herein called PPMCS (Preharvest Produce Microbial Contamination Simulator). Also, fecal contamination of preharvest produce was simulated using PPMCS. Although Agent-based Modeling and Simulation, the tool applied in this study, is rather popular in where socio-economical human behaviors or ecological fate of animals in their niche are to be predicted, the incidence of on-farm produce contamination which are thought to be sporadic has never been simulated using this tool. The agents in PPMCS including crop, animal as a source of fecal contamination, and fly as a vector spreading the fecal contamination are given their intrinsic behaviors that are set to be executed at certain probability. Once all these agents are on-set following the intrinsic behavioral rules, consequences as the sum of all the behaviors in the system can be monitored real-time. When fecal contamination of preharvest produce was simulated in PPMCS as numbers of animals, flies, and initially contaminated plants change, the number of animals intruding cropping area affected most on the number of contaminated plants at harvest. For further application, the behaviors and variables of the agents are adjustable depending on user's own scenario of interest. This feature allows PPMCS to be utilized in where different simulating conditions are tested.

Endophytic Trichoderma gamsii YIM PH30019: a promising biocontrol agent with hyperosmolar, mycoparasitism, and antagonistic activities of induced volatile organic compounds on root-rot pathogenic fungi of Panax notoginseng

  • Chen, Jin-Lian;Sun, Shi-Zhong;Miao, Cui-Ping;Wu, Kai;Chen, You-Wei;Xu, Li-Hua;Guan, Hui-Lin;Zhao, Li-Xing
    • Journal of Ginseng Research
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    • v.40 no.4
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    • pp.315-324
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    • 2016
  • Background: Biocontrol agents are regarded as promising and environmental friendly approaches as agrochemicals for phytodiseases that cause serious environmental and health problems. Trichoderma species have been widely used in suppression of soil-borne pathogens. In this study, an endophytic fungus, Trichoderma gamsii YIM PH30019, from healthy Panax notoginseng root was investigated for its biocontrol potential. Methods: In vitro detached healthy roots, and pot and field experiments were used to investigate the pathogenicity and biocontrol efficacy of T. gamsii YIM PH30019 to the host plant. The antagonistic mechanisms against test phytopathogens were analyzed using dual culture, scanning electron microscopy, and volatile organic compounds (VOCs). Tolerance to chemical fertilizers was also tested in a series of concentrations. Results: The results indicated that T. gamsii YIM PH30019 was nonpathogenic to the host, presented appreciable biocontrol efficacy, and could tolerate chemical fertilizer concentrations of up to 20%. T. gamsii YIM PH30019 displayed antagonistic activities against the pathogenic fungi of P. notoginseng via production of VOCs. On the basis of gas chromatography-mass spectrometry, VOCs were identified as dimethyl disulfide, dibenzofuran, methanethiol, ketones, etc., which are effective ingredients for antagonistic activity. T. gamsii YIM PH30019 was able to improve the seedlings' emergence and protect P. notoginseng plants from soil-borne disease in the continuous cropping field tests. Conclusion: The results suggest that the endophytic fungus T. gamsii YIM PH30019 may have a good potential as a biological control agent against notoginseng phytodiseases and can provide a clue to further illuminate the interactions between Trichoderma and phytopathogens.

Clean-up of the Crude Oil Contaminated Marine Sediments Through Biocarrier-Mediated Bioaugmentation (생물담체 활용 생물접종에 의한 원유로 오염된 해양토양의 정화)

  • Ekpeghere, Kelvin I.;Bae, Hwan-Jin;Kwon, Sung-Hyun;Kim, Byung-Hyuk;Park, Duck-Ja;Kim, Hee-Shik;Koh, Sung-Cheol
    • Korean Journal of Microbiology
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    • v.45 no.4
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    • pp.354-361
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    • 2009
  • This study was carried out to develop an effective biocarrier-mediated bioaugmentation technology which will be useful for remediation of the crude oil-contaminated marine sediments. Enrichment of several microbial communities was made from several oil-polluted seashore sites and the two distinctively functional consortia have been successfully selected. These two consortia were grown together and used to manufacture the microbial agents for bioaugmentation of marine sediments polluted with crude oil. The most dominant species in the mixed culture was identified as Alcanivorax borkumensis based on pure culture and DGGE analysis. Bioaugmentation of oil-polluted marine sediments with the microbial agent MA-2 formulated using the mixed culture and biocarriers (activated carbon and minerals) was more effective, especially in combination with an oxygen producing (releasing) compound (ORC). Ninty percent of TPH was removed in the presence of ORC in 35 days while 74% in the absence of ORC. This indicated that the indigenous consortial degraders could be immobilized on the active carbon as a biocarrier to manufacture microbial agents and then effectively bioaugmented for remediation of the oil-polluted sediments.

Effects of glycine on microbial safety of low-salted squid and myungran jeotgal (글리신을 활용한 저염 오징어 및 명란 젓갈의 미생물 안전성 확보)

  • Choi, Jun-Bong;Cheon, Hee Soon;Chung, Myong-Soo;Cho, Won-Il
    • Korean Journal of Food Science and Technology
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    • v.51 no.2
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    • pp.114-119
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    • 2019
  • Seven antimicrobial agents known to be effective in inhibiting the growth of lactic acid bacteria were applied to ensure the microbial safety of low-salted squid and myungran jeotgal with 4-6% salinity. These agents reduced the salt content by 50% compared with the conventional Jeotgal. Lactic acid bacteria such as Lactobacillus sp., Streptococcus sp., and Pediococcus sp. were commonly found to account for 80% of microbial organisms, and yeast and fungi were observed in squid and myungran jeotgal, respectively. The total bacterial counts in squid and myungran jeotgal showed 94.20 and 90.87% reduction after the addition of 0.5% (w/w) glycine. The microbial counts in squid and myungran jeotgal decreased $10^1-10^2CFU/g$ when compared with the control after 21 days at $10^{\circ}C$. Glycine was found to be an effective commercial antimicrobial agent that can be used to control bacterial count in low-salted Jeotgal without affecting sensory qualities such as overall taste and flavor.

Monitoring of Microbial Contamination in Air Purifier for Preventing Cross-contamination (교차오염방지를 위한 공기정화제품에서 미생물 오염도 분석)

  • Yeom, Seung-Mok;Kim, Young-Mog;Lee, Myung-Suk
    • Journal of Food Hygiene and Safety
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    • v.31 no.3
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    • pp.201-209
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    • 2016
  • Many atmospheric pollutants including chemical agents, house dust, and microorganisms cause building-related illnesses through respiration in humans. This study was conducted to analyze the profiles of microbial pollutants in air purifiers used in home, office and playschool. Dominant eleven species of microorganisms were isolated and identified in environmental air and air purifiers. Among them, Staphylococcus sp., Micrococcus sp. and Bacillus sp. are the most dominant species. By phylogenetic analysis of the 16S rRNA gene, the dominant bacteria were identified as Staphylococcus epidermidis, Micrococcus luteus and Bacillus epidermidis, respectively. It has been known that these bacterial species are closely related with food spoilage and human infectious disease. Thus, these results indicate that microbial pathogens related with human illnesses through respiration will be contaminated in air purifiers and also need to develop a method to control those of pathogens for human health.