• Journal of Microbiology and Biotechnology
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• 제21권6호
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• pp.556-566
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• 2011

A total of 31 Acinetobacter isolates were obtained from the rhizosphere of Pennisetum glaucum and evaluated for their plant-growth-promoting traits. Two isolates, namely Acinetobacter sp. PUCM1007 and A. baumannii PUCM1029, produced indole acetic acid (10-13 ${\mu}g$/ml). A total of 26 and 27 isolates solubilized phosphates and zinc oxide, respectively. Among the mineral-solubilizing strains, A. calcoaceticus PUCM1006 solubilized phosphate most efficiently (84 mg/ml), whereas zinc oxide was solubilized by A. calcoaceticus PUCM1025 at the highest solubilization efficiency of 918%. All the Acinetobacter isolates, except PUCM1010, produced siderophores. The highest siderophore production (85.0 siderophore units) was exhibited by A. calcoaceticus PUCM1016. Strains PUCM1001 and PUCM1019 (both A. calcoaceticus) and PUCM1022 (Acinetobacter sp.) produced both hydroxamate-and catechol-type siderophores, whereas all the other strains only produced catechol-type siderophores. In vitro inhibition of Fusarium oxysporum under iron-limited conditions was demonstrated by the siderophore-producing Acinetobacter strains, where PUCM1018 was the most potent inhibitor of the fungal phytopathogen. Acinetobacter sp. PUCM1022 significantly enhanced the shoot height, root length, and root dry weights of pearl millet seedlings in pot experiments when compared with controls, underscoring the plant-growth-promoting potential of these isolates.

• Journal of Applied Biological Chemistry
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• 제59권3호
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• pp.173-178
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• 2016

Phenyllactic acid (PLA), which is a known antimicrobial compound, can be synthesized through the reduction of phenylpyruvic acid (PPA) by lactate dehydrogenase of lactic acid bacteria (LAB). PLA-producing LAB was isolated from coffee beans, and the isolated LAB was identified as Lactobacillus zeae Y44 by 16S rRNA gene sequence analysis. Cell-free supernatant (CFS) from L. zeae Y44 was assessed for both its capability to produce the antimicrobial compound PLA and its antifungal activity against three fungal pathogens (Rhizoctonia solani, Botrytis cinerea, and Colletotrichum aculatum). PLA concentration was found to be 4.21 mM in CFS when L. zeae Y44 was grown in MRS broth containing 5 mM PPA for 12 h. PLA production could be promoted by the supplementation with PPA and phenylalanine (Phe) in the MRS broth, but not affected by 4-hydroxy-phenylpyruvic acid, and inhibited by tyrosine as precursors. Antifungal activity assessment demonstrated that all fungal pathogens were sensitive to 5 % CFS (v/v) of L. zeae Y44 with average growth inhibitions ranging from 27.8 to 50.0 % (p<0.005), in which R. solani was the most sensitive with an inhibition of 50.0 %, followed by B. cinerea and C. aculatum. However, pH modification of CFS to pH 6.5 caused an extreme reduction in their antifungal activity. These results may indicate that the antifungal activity of CFS was caused by acidic compounds like PLA or organic acids rather than proteins or peptides molecules.

• 한국버섯학회지
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• 제14권4호
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• pp.162-167
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• 2016

Lactic acid bacteria (LAB) producing phenyllactic acid (PLA), which is known as antimicrobial compound, was isolated from button mushroom bed and the isolated LAB was identified to Lactobacillus casei by 16 rRNA gene sequence analysis. Cell-free supernatant (CFS) from L. casei was assessed for both the capability to produce the antimicrobial compound PLA and the antifungal activity against three fungal pathogens (Rhizoctonia solani, Botrytis cinerea, and Collectotricum aculatum). PLA concentration was investigated to be 3.23 mM in CFS when L. casei was grown in MRS broth containing 5 mM phenylpyruvic acid as precursor for 16 h. Antifungal activity demonstrated that all fungal pathogens were sensitive to 5% CFS (v/v) of L. casei with average growth inhibitions ranging from 34.58% to 65.15% (p < 0.005), in which R. solani was the most sensitive to 65.15% and followed by C. aculatum, and B. cinerea. The minimum inhibitory concentration (MIC) for commercial PLA was also investigated to show the same trend in the range of 0.35 mg mL-1 (2.11 mM) to 0.7 mg mL-1 (4.21 mM) at pH 4.0. The inhibition ability of CFS against the pathogens were not affected by the heating or protease treatment. However, pH modification in CFS to 6.5 resulted in an extreme reduction in their antifungal activity. These results may indicate that antifungal activities in CFS was caused by acidic compounds like PLA or organic acids rather than protein or peptide molecules.

• The Plant Pathology Journal
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• 제24권4호
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• pp.453-460
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• 2008

In the course of in vitro and in vivo screening for bioherbicidal agents, a hyphomycete fungus, Myrothecium sp. F0252 was selected as a candidate for the biocontrol of weeds. The isolate was identified as Myrothecium roridum Tode ex. Fries based on the morphological characteristics and 18S ribosomal DNA sequence analysis and registered as Myrothecium roridum F0252. In order to evaluate the in vitro effect of M. roridum F0252 on germination of ladino clover and white clover (Trifolium repens L.) seeds, spore solution of the fungus was employed in two concentrations, $6.5{\times}10^6$ and $2.5{\times}10^7$ spores per mL and then inoculated to the seeds. The fungal spores inhibited the seed germination, infected the seedlings, and caused an abnormal withering and inhibition of seedling growth. In addition, when the herbicidal activity of crude ethyl acetate extract from the liquid culture was assessed on a mini-plant, duck-weed (Lemna paucicostata (L.) Hegelm.), the extract showed high inhibitory effect at the level of $12.5{\mu}g$ per mL. On the other hand, in vivo herbicidal activity of M. roridum F0252 was evaluated by a whole plant spray method. M. roridum F0252 exhibited strong and broad-spectrum herbicidal activity. The herbicidal values ranged from 95-100% against 7 weeds, including Abutilon avicennae and Xanthium strumarium, and 70-80% against Digitaria sanguinalis and Sagittaria pygmaea. When the nutritional utilization (95 carbon sources) pattern of M. roridum F0252 was investigated, it varied with water activity ($a_w$) and temperature conditions, supplying good, basic information in regard to nutritional utilization for proper cultivation and formulation. Our results showed that M. roridum F0252 might be used as a potential biocontrol agent against weedy plants.

• 한국환경농학회지
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• 제31권1호
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• pp.60-67
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• 2012

옻나무 주성분인 조추출액의 고추 탄저병균에 대한 항진균활성을 조사한 결과 1.0 mg urushiol/mL PDA 농도에서 18.3-39.5%의 억제효과가 있었으며, 푸른 고추에 병원성이 강한 것으로 조사된 GC계열의 균주보다는 DC계열의 균주에 대한 효과가 높았다. Urushiol의 농도가 1.0 mg/mL 일 경우 약 70% 정도의 포자가 발아한 PDB 용액에서보다 공시 모든 균주의 포자발아는 50% 이상 억제되었다. 동일한 농도에서 균사생장억제 효과 보다는 포자발아에 대한 억제 효과가 다소 높은 경향을 보였다. 푸른 고추와 붉은 고추에 옻 추출액을 처리하고 공시 탄저병균을 접종한 후 병 발생 억제효과를 in vitro에서 검정한 결과 붉은 고추에 DC 균주를 접종하였을 경우 1.0 mg/mL 농도 처리에서는 75.0%, 0.1 mg/mL 농도 처리에서는 58.0% 로 나타났으며, 푸른고추에 병원성이 강한 GC 균주를 접종하였을 경우에는 각각 68.1% 및 28.3% 탄저병 발생이 억제되었다. 비닐하우스에서 관행재배방법에 의해 고추를 재배하면서 고추 탄저병이 자연발생하기 시작한 8월 21부터 옻 추출액을 1주일 간격으로 3회 살포하고 최종 살포일 7일 후에 전체 고추 열매 중 이병 열매를 조사하여 옻 추출액의 병 발생 억제정도를 구한 결과 1차 조사한 9월 11일에는 무처리 대조구에 비해 옻 조 추출액을 1.0 mg/mL 처리한 시험구에서는 85.0% 탄저병 발생 억제효과를 보였으나, 0.01 mg/mL 처리구에서는 9.8%의 낮은 억제효과를 보였다. 9월 11일 조사 후 이병 열매를 모두 제거한 다음 동일한 방법으로 옻 추출액을 계속처리하고 10월 2일에 조사한 결과 1차 조사 시기보다 대조구의 이병과율이 훨씬 낮은 7.0% 였으며, 옻 추출액 처리효과는 공시 처리 농도별로 각각 60.0, 54.3 및 10.0%로 조사되었다.

• Mycobiology
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• 제29권1호
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• pp.19-26
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• 2001

Defense mechanisms against anthracnose disease caused by Colletotrichum orbiculare on the leaf surface of cucumber plants after pre-treatment with plant growth promoting rhizobacteria(PGPR), amino salicylic acid(ASA) or C. orbiculare were compared using a fluorescence microscope. Induced systemic resistance was mediated by the pre-inoculation in the root system with PGPR strain Bacillus amylolquefaciens EXTN-1 that showed direct antifungal activity to C. gloeosporioides and C. orbiculare. Also, systemic acquired resistance was triggered by the pre-treatments on the bottom leaves with amino salicylic acid or conidial suspension of C. orbiculare. The protection values on the leaves expressing SAR were higher compared to those expressing ISR. After pre-inoculation with PGPR strains no change of the plants was found in phenotype, while necrosis or hypersensitive reaction(HR) was observed on the leaves of plants pre-treated with ASA or the pathogen. After challenge inoculation, inhibition of fungal growth was observed on the leaves expressing both ISR and SAR. HR was frequently observed at the penetration sites of both resistance-expressing leaves. Appressorium formation was dramatically reduced on the leaves of plants pre-treated with ASA, whereas EXTN-1 did not suppress the appressorium formation. ASA also more strongly inhibited the conidial germination than EXTN-1. Conversely, EXTN-1 significantly increased the frequency of callose formation at the penetration sites, but ASA did not. The defense mechanisms induced by C. orbiculare were similar to those by ASA. Based on these results it is suggested that resistance mechanisms on the leaf surface was different between on the cucumber leaves expressing ISR and SAR, resulting in the different protection values.

• 한국미생물·생명공학회지
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• 제37권3호
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• pp.280-286
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• 2009

황련의 식물병원성 곰팡이에 대한 항진균 활성을 평가하기 위해 황련 메탄올 추출물 및 유기용매 분획물들을 조제하여 Colletotrichum gloeosporioides(고추탄저 병), Phytohpthora capsici(고추역병), Pyricularia grisea(벼도열병), Rhizoctonia solani(잎집무늬마름병), Botryosphaeri dothidea(겹무늬썩음 병), Glomerella cingulata(사과과실 탄저병) 및 Botrytis cinerea(잿빛곰팡이병)의 7종에 대해 $0{\sim}1,000{\mu}g/mL$ 농도로 처리한 후, 포자발아억제 활성 및 균사체 생육억제 활성을 평가하였다. 그 결과 황련 메탄올 추출물은 $500{\mu}g/mL$ 농도에서 B. dothidea를 제외한 6종의 곰팡이의 포자발아를 억제하였으며, P. grisea 및 B. cinerea에 대해 $300{\mu}g/mL$의 MIC를, P. capsici에 대해서는 $500{\mu}g/mL$의 MIC를 나타내었고, 다른 4종에 곰팡이에 대해서는 균사체 성장억제 활성이 나타나지 않았다. 고추 재배지의 실제적 적용을 위해 대량 추출조건을 선정한 후, 상업적 시설에서 열수 추출물($1,000{\mu}g/mL$)을 조제하고, 이를 6월부터 한달 간격으로 3회에 걸쳐 엽면살포한 결과 병해와 약해가 전혀 나타나지 않았다. 황련 살포에 의해 고추의 전반적인 생육, 잎, 뿌리 발육이 촉진되었으며, 고추는 평균중량이 119%, 과육의 두께가 평균 117% 증가되어 생육촉진 및 수확량 증가효과를 확인하였다. 본 연구결과는 황련 추출물이 고추 관련 질병 방제에 유용하며, 고추생육 촉진효과를 가짐을 시사하고 있다.

• 식물병연구
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• 제25권3호
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• pp.114-123
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• 2019

Quantum Dot LED (QD LED) 조명은 소형의 크기, 좁은 대역파장, 긴 수명, 전자 시스템을 통한 제어가 용이하여 현재 시설재배에 이용되는 형광등, 할로겐램프, HID, HSP 램프의 단점을 보완할 수 있는 작물생육에 이상적인 광원으로서 잠재력을 가지고 있다. QD LED 조명을 이용하여 식물 병원성 미생물의 방제가 가능하다면 작물재배에 사용되는 인력 및 비용을 절감하고 화학적 방제제를 사용하지 않은 안전성 높은 생산물을 얻을 수 있다는 장점이 있다. 본 연구에서는 식물공장 및 온실에서 많이 재배되고 있는 상추에 큰 피해를 입히는 주요 식물 병원성 곰팡이에 대한 QD LED 조명의 영향과 생장억제효과를 확인하기 위해 시행하였다. 상추에 주로 발생하여 작물에 피해를 입히는 Rhizoctonia solani, Phytophthora drechsleri, Sclerotinia sclerotiorum, Sclerotinia minor, Botrytis cinerea, Fusarium oxysporum, Pectobacterium carotovorum, Xanthomonas campestris균을대상으로 QD LED 조명에 의한 균사생장억제 효과를 조사하였으며 처리한 6종류의 조명 중 BLUE (450 nm) 조명은 Sclerotinia sclerotiorum는 50 cm 거리에서 16.7%의 억제율을 보였으며 30 cm 거리에서 94.1%의 균사생장억제율을 보였다. S. minor는 50 cm 거리에서 80.4%, B. cinerea는 50 cm 거리에서 36.3%의 균사생장이 억제되었으며 30 cm 거리에서 S. minor와 B. cinerea는 100%의 균사생장억제율을 보였다. 15 cm 거리에서는 3종의 병원균 모두 100%의 억제율을 보였다. QD RED (M1), QD RED (M2)조명은 30 cm와 15 cm 거리에서 Sclerotinia minor와 Botrytis cinerea의 균사생장을 100% 억제했으며 Sclerotinia sclerotiorum의 경우 30 cm 거리에서 QD RED (M1)과 QD RED (M2)조명에 대해 각각 75.2%, 100%의 억제율을 보였으나 15 cm 거리에서는 각각 5.8%, 36.3%의 억제율을 보였다. 상추에 병원균을 접종하여 LED 광원 하에 생장을 확인한 결과 QD RED (M2)광원에서 S. sclerotiorum의 감염을 59.9% 억제하였고 S. minor는 BLUE (450 nm), QD RED (M1), QD RED (M2) 광원에서 59.9%의 억제율을 보였다. B. cinerea의 경우 BLUE (450 nm) 광원에서 84%의 높은 억제율을 보였다.

• Bulletin of the Korean Chemical Society
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• 제33권9호
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• pp.2985-2990
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• 2012

New thiazoline derivatives 7a-c, and thiophenes 9a-c linked to indole moiety were easily prepared via the reaction of the acrylamide derivative 3 with phenacyl bromides 4a-c, depending on the reaction conditions. In addition, the reaction of compound 3 with hydrazonoyl chlorides 11a-f afforded a series of 1,3,4-thiadiazole derivatives 13a-f. Moreover, coupling of 3-(3-methyl-1H-indol-2-yl)-3-oxopropanenitrile (2) with the diazonium salts of 3-phenyl-5-aminopyrazole 16 or 3-amino-1,2,4-triazole 17 gave the corresponding hydrazones 18 and 19, respectively. Cyclization of the latter hydrazones yielded the corresponding pyrazolo[5,1-c]-1,2,4-triazine and 1,2,4-triazolo[5,1-c]-1,2,4-triazine derivatives 20 and 21, respectively. The structures of the synthesized compounds were assigned on the basis of elemental analysis, IR, $^1H$ NMR and mass spectral data. All the synthesized compounds were tested for in vitro activities against certain strains of fungi such as Aspergillus niger, Aspergillus nodulans, Alternaria alternate. Compounds showed marked inhibition of fungal growth nearly equal to the standards.

• 한국수산과학회지
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• 제42권1호
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• pp.34-40
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• 2009

In fresh water fish hatcheries and farms, Saprolegniales often cause serious mortality to the fish and their eggs. Malachite green is an effective antifungal agent, but is carcinogenic to fish and humans. Alternative antifungal agents are needed. Presently, we tested various concentrations of MBT-01108 (Opuntia ficus-indica extracts) alone and in combination with bronopol, formalin and sodium chloride (MBT-01108 mixture) on in vitro mycelial growth and in vivo remediation of adult eel, Anguilla japonica, infected with Saprolegnia sp. and fertilized eggs of chum salmon, Oncorhynchus keta, to evaluate the compounds' antifungal efficacy on eyed-egg and hatching rates. MBT-Oll08 mixtures incorporating bronopol and formalin at respective concentrations of 50 and 30 parts per million (ppm), and 100 and 20 ppm were most effective in controlling Saprolegnia in vitro and in vivo (P<0.05). Repeated daily exposures to 50 ppm and 100 ppm MBT-01108 were more effective than exposure every 2-3 days post-fertilization for the inhibition of Saprolegnia infection of rainbow trout, Oncorhynchus mykiss eggs as compared with control (0 ppm).