In this study, Bacillus velesensis TJS119, isolated from freshwater, demonstrated growth inhibition against insect pathogenic fungi. The culture medium of the B. velezensis TJS119 strain underwent sequential fractionation with n-hexane, chloroform, ethyl acetate, n-butanol, and water. Notably, the n-butanol fraction exhibited significant antifungal activity against Metarhizium anisopliae and Beauveria bassiana. LC/MS analysis of antifungal peaks identified the production of various lipopeptides by B. velezensis TJS119, including two types of iturin A (C14, C15), four types of fengycin A (C14, C15, C16, C17), and two types of fengycin B (C16, C17). The antifungal efficacy of Iturin A and Fengycin against insect pathogenic fungi was further validated using the paper disc diffusion method. These findings underscore the potential of B. velezensis TJS119 as a promising candidate for future research and applications in the realm of agricultural biological controls against fungal diseases.

In this study, we analyzed the antifungal activities of five essential oils (clove, rosemary, thyme, basil, and oregano) against three fungi (Penicillium oxalicum, Penicillium commune, and Cladosporium cladosporioides) isolated from farm-type fermented meat products Though their antifungal activities differed for each fungus, thyme had the greatest effect. Notably, C. cladosporioides showed the highest sensitivity to essential oils, and growth inhibitory effects were greater than for the other two strains. Additionally, ABTS, DPPH, and FRAP analysis confirmed that the five essential oils studied had antioxidant activity. ABTS analysis showed that clove (75%) and oregano (75%) oils had the highest antioxidant activities (both 93.7%). DPPH analysis showed that clove (75%) and rosemary (75%) oils had significantly greater antioxidant activities (both 93.8%) than thyme, basil, or oregano oils. FRAP results indicated that clove and basil oils were the strongest reductants. Comprehensive comparative analysis indicated that clove oil had more antioxidant activity than the other four essential oils. Overall, the study shows that the excellent antifungal properties of clove oil could be harnessed to produce safe fermented meat products by preventing rancidity and mold contamination.

A new Bacillus thuringiensis isolate 19-22 (Bt 19-22) exhibited high anti-fungal activity against barley powdery mildew (Blumeria graminis f. sp. hordei). The cry gene content of Bt 19-22 comprised cry1Aa, cry1Ab, cry1Ac and cry1D which have high insecticidal activity against lepidopteran larvae. We tried to confer a dipteran insecticidal activity to Bt 19-22 for constructing a recombinant strain which has multiple functions, anti-fungal and dual insecticidal activity. The insecticidal cry11Aa gene of B. thuringiensis was constructed under cry1Ac promoter in an E. coli-B. thuringiensis shuttle vector (pPro11A). The plasmid, pPro11A was introduced into Bt 19-22 isolate by electroporation and four transformants which had different cry gene contents were identified by PCR with cry11Aa and cry1-type specific primers. Among them, a Bt 19-22 transformant (11A/19-22 No. 7) expressed Cry11A protein (approximately 70 kDa) successfully without change of its inherent characteristics such as Cry protein expression and antifungal activity. The insecticidal activity of 11A/19-22 No. 7 was checked against Plutella xylostella and Culex pipiens. These results suggests that the recombinant strain shows dual insecticidal activity against lepidopteran and dipteran larvae as well as antifungal activity.

6-(4-Iodophenyl)amino-7-chloro-5,8-quinolinedione (RCK9) was evaluated for antifungal activities. The MIC values of RCK9 were determined against A. flavus, C. albicans, C. neoformans and F. oxysporium. The RCK9 showed generally potent antifungal activities against the tested fungi. Acute oral toxicity studies of RCK9 were carried out in ICR mice of both sexes. These acute oral toxicities of RCK9 were low and LDSO values were over 2,850 mg/kg in ICR mice. The genotoxicities of RCK9 had been evaluated. RCK9 was negative in Ames test with Salmonella typhimurium and chromosomal aberration test in CHL cells. The clastogenicity was tested on the RCK9 with in vivo mouse micronucleus assay. RCK9 did not show any clastogenic effect in mouse peripheral blood and was negative in mouse micronucleus assay. The results indicate that RCK9 has no genotoxic potential under these experimental conditions.

6-[(N-3,4-Dibromophenyl)amino]-7-chloro-5,8-quinolinedione(RCK13) was tested for antifungal activities. The MIC values were determined by the two-fold dilution method. The therapeutic potential of RCK13 had been assessed in comparison with ketoconazole and fluconazole against systemic infections with Candida albicans in normal mice. RCK13 had ED_(50), 0.80±0.21 mg/kg but ketoconazole had ED_(50), 8.00±0.73 mg/kg respectively. And administered RCK13 at the ED_(50) for 14 days improved survival rates as well as ketoconazole. Acute oral toaicity studies of RCK13 were carried out in ICR mice of both sexes. These acute oral toxicities of RCK13 were low and LD_(50) values were over 2,850 mg/kg in ICR mice. The genotoxicities of RCK 13 had been evaluated. RCK13 was negative in Ames test with Salmonella ryphimurium and chromosomal aberration test in CHL cells. The clastogenicity was tested on the RCK13 with in vivo mouse micronucleus assay. RCK13 did not show any clastogenic effect in mouse peripheral blood and was negative in mouse micronucleus assay. These results indicate that RCK13 has no genotoxic potential under these experimental conditions.

Plant extracts were screened for antifungal activity against major plant pathogens, Botrytis sp., Collectotrichum sp., Alternaria sp. and Cylindrocarpon sp. using 96-well microdilution method. Among the 662 methanol extracts from 401 plant species, 36 extracts showed complete inhibition of spore germination against at least one of four pathogenic fungi. Extracts of Morus alba twig and Sophora flavescens root showed minimum inhibition concentration (MIC) at 1,250 ㎍/㎖ against Botrytis sp.. Extracts of Chloranthus japonicus root showed MIC at 1,250 ㎍/㎖ against Collectotrichum sp.. Extracts of Glycyrrhiza uralensis aerial part, Inula helenium root and Menispermum dauricum root showed MIC between 625 and 1,250 ㎍/㎖ against Alternaria sp.. G. uralensis aerial part and I. helenium root showed MIC at 1,250 ㎍/㎖ against Cylindrocarpon sp.. Specifically, the extracts of Agrimonia pilosa root, Angelica tenuissima root, Asarum sieboldii root, Campsis grandifolia leaf and twig, Cnidium officinale root, Dictamnus dasycarpus root, G. uralensis aerial part, I. helenium root and M. alba twig completely inhibited spore germination at lower than 5,000 ㎍/㎖ against all of four pathogenic fungi. Two methanol extracts from G. uralensis aerial part and M. alba twig may used as a candidate to develop into effective disease management materials in plant cultivation.

The study researched germination of the plants and growth of Fungus according to concentration of aqueous extracts in order to provide basic data for developing natural agricultural resources by using Persicaria longiseta. The seed germination of Amaranthus spinosus was inhibited at 25% P. longiseta extract, while Agrostis stolonifera ssp. palustris was not affected at all concentrations tested. Especially, the seed germination rate and fresh weight of Trifolium incarnatum at 20% P. blumei extract were higher than those of control plot. The early growth of most receptor plant seedlings was promoted at 25% and 50% of P. blumei extracts, but the radicle growth of all receptor plants was significantly inhibited at > 25% of P. longiseta extract. The response of receptor plants to P. longiseta extract was different according to the plant species and the plant parts. The growth of plant pathogenic fungus in PDA medium showed an increasing inhibition tendency with increasing concentrations of P. longiseta extract. Especially, P. longiseta extract showed the greatest antimicrobial activity against Phytophthora infestans, Phythium graminicola, and Pythium venterpoolii. The content of total phenolic compound in P. longiseta was higher in leaves (1082.3 mg/L) but lower in roots (228.6 mg/L) and stems (207.8 mg/L), which is an allelopathic chemical. As these results are summarized, P. longiseta have competitive advantage because they release phenolic compounds with allelopathic effect and affect on germination, growth and fungi growth on underground flora compared to native plants and they have eligibility for natural herbicide and germicide.

Zoysiagrass are damaged by fungi diseases such as large patch, dollar spot, pythium blight and brown patch. Large patch is one of the major diseases caused by Rhizoctonia solani AG2-2 on zoysiagrass fields e.g. golf courses. Plant chitinases have been known PR (Pathogen related)-protein. In this study, we isolated two chitinase genes (Zjchi1 and Zjchi2) from zoysiagrass. Antifungal activity analysis revealed that Zjchi2 protein inhibited mycelium extension of fungi. A further study, we cloned 5` upstream region from two chitinase genes for investigating transcription regulatory mechanism that inducing of two chitinase genes dependent R. solani. -818 bp and -799 of upstream region from Zjchi1 and Zjchi2 successfully isolated using in vitro LA (Long and Accurate) PCR system. And then, we generated promoter-GUS reporter constructs with deletion construct based on W-boxes. Constructs were introduced into Arabidopsis thaliana by Agrobacterium-mediated transformation for stable expression of GUS reporter gene.

본 연구는 귀화식물인 Solidago altissima, Amaranthus retroflexus, Sida spinosa 등을 이용하여 친환경 농자재로 개발하기 위한 기초자료를 제공하기 위해 수용성 추출액의 농도에 따른 수용체 식물의 발아 및 유식물 생장과 실험 병원균의 생장을 조사하였다. 공여체식물에 따른 수용성 추출액 농도가 증가됨에 따라 대부분 검정식물의 상대발아율은 감소하는 경향을 보이는데 S. spinosa(r = -0.540, p＜0.01), Physalis wrightii(r = -0.693, p＜ 0.01), A. retroflexus(r = -0.724, p＜0.01), S. altissima(r = -0.728, p＜0.01), Eclipta prostrata(r = -0.779, p＜0.01) 순으로 감소하는 경향이 큰 것으로 조사되었고 평균발아일수도 처리구 농도가 증가함에 따라 발아하는데 소요되는 시간이 증가 되었으며(r=0.769, p＜0.01) 공여체식물과 검정식물에 따라 약간의 정도 차이를 보였다. 또한 공여체식물의 수용성 추출액 농도가 증가함에 따라 유식물의 지상부의 길이(r = -0.587, p＜0.01), 지하부의 길이(r = -0.741, p＜0.01), 생체량(r = -0.574, p＜0.01)과 뿌리털의 발생도 감소하였다. 한편 공여체식물의 수용성추출액 농도 증가에 따른 검정 병원균의 생장은 Botrytis cinerea(r = -0.266, p＜0.05), Diaporthe citri(r = -0.323 p＜0.01), Colletotrichum gloeosporioides(r = -0.512, p＜0.01), Pythium ultimum(r = -0.581, p＜0.01), Rhizoctonia solani(r = -0.806, p＜0.01) 순으로 생장이 억제되었다. 제초 및 항균활성을 보이는 수용체식물의 총 페놀 함량은 S. altissima 17.3±0.5mg/g, A. retroflexus 13.1±0.3mg/g, P. wrightii 12.0±0.4mg/g, S. spinosa 9.5±0.1mg/g, E. prostrata 4.1±0.1mg/g 순으로 분석되었다. 이들 결과를 종합하면 귀화식물인 수용체식물들은 자생식물과의 경쟁을 함에 있어 알레로패시 효과를 나타내는 페놀 화합물 등이 수관 내 토양으로 방출하여 하부식생에 대한 발아 및 생장과 토양미생물 생장 등에 영향을 주기 때문에 경쟁적 우위를 점하고 있으며, 천연제초제 · 살균제로서의 활용 가능성을 가지고 있는 것으로 판단된다.

천연물은 예로부터 건강의 증진 및 질병의 치료를 위하여 다양하게 이용되어 왔다. 특히 천연물 및 식품류에 포함되어 있는 폴리페놀성 화합물들은 항산화, 암세포 성장억제, 항돌연변이 등 다양한 생리활성을 나타내어 심혈관계 질환 및 암의 치료와 예방제로서의 활용 가능성을 검토하는 많은 연구가 이루어지고 있다. 따라서 본 연구에서는 동백나무의 기능성 물질 확보와 가공을 통한 고부가가치 창출을 목표로 국내에서 자생하는 동백나무를 부위별로 추출물을 제조하여 항산화 및 항미생물 활성을 평가하고자 하였다. 항산화효과는 항산화력 성분인 총페놀 화합물의 함량과 BPPH radical 소거법을 이용하여 항산화 활성을 측정하였는데 총페놀 화합물의 함량은 동백나무 부위별 추출물의 건조중량 100 g에 대하여 어린잎, 꽃봉오리 및 꽃 추출물에 각각 74.24mg , 65.02mg, 그리고 62.42mg로 나타났다. Free radical소거활성을 공존시킨 DPPH의 50%를 환원시키는데 필요한 시료의 양 (RC50)은 어린잎, 꽃봉오리 그리고 꽃의 추출물에서 각각 7.16 μg/ml, 14.45 μg/ml 및 18.4 μg/ml의 낮은 농도로 활성을 나타내어 기존의 합성 항산화제인 BHT의 61.23 μg/ml보다 높은 항산화 효과를 나타내어 천연 항산화제로서 이용 가능성을 보여주었다. 또한 B. subitillis, S. fradiae, S. aureus, E. coli, P. aeruginosa, Enterbacter spp. C1036 및 S. typhimurium 7종의 시험균을 사용하여 동백나무 부위별 추출물의 항균활성을 측정 하였는데 어린잎의 경우 15 μg/ml의 농도에서 9~13mm의 투명환을 보여 비교적 높은 항미생물 활성을 나타내었고, 꽃봉오리 추출물을 첨가하였을 때 P. aeruginosa와 Enterbacter spp. C1036 균주에서 가장 장한 억제활성을 나타내었다. 7종의 시험균에 대한 항균력이 가장 높았던 어린일 추출물의 최소저해농도 (MIC)는 1~15으로 나타났으며, 그람양성균이 그람음성균보다 각 농도에서 최소저해농도의 효과가 더 높은 것으로 나타났다.