Production Of Antifungal Substances Research Articles

탄저병균에 대하여 길항작용을 보이는 Burkholderia cepacia EB215로부터 분리한 Pyrrolnitrin의 항균활성

오이 뿌리조직으로부터 분리한 식물내생세균 EB215균은 탄저병균인 Colletotrichum species에 대하여 강한 항균활성을 보였다. 이 균은 생리 생화학적 특성과 Biolog 실험 및 16S rDNA 유전자 서열에 의해 Burkholderia cepacia로 동정되었다. 이 균의 항균물질 생산을 위한 최적배지는 nutrient 액체(NB) 배지로 그리고 배양기간은 3일로 결정되었다. B. cepacia EB215 균주의 NB 배양체로부터 원심분리, n-hexane 분획, silica gel 컬럼, preparative TLC 및 in vitro 생물검정 등을 통하여 한 개의 항균물질을 분리하였다. 이 물질은 질량분석과 핵자기공명 분석을 통하여 pyrrolnitrin으로 동정되었다. Pyrrolnitrin은 고추 탄저병(Colletotrichum coccodes), 오이 탄저병(Colletotrichum orbiculare), 벼 도열병(Magnaporthe grisea), 벼 잎집무늬마름병(Corticium sasaki) 등의 4가지 식물병에는 <TEX>$11.1\;{\mu}g/ml$</TEX> 낮은 농도에서도 90% 이상의 높은 방제활성을 보였다. 그리고 또한 토마토 잿빛곰팡이병(Botrytis cinerea)과 밀 붉은녹병(Puccinia recondita)에 대해서는 <TEX>$33.3\;{\mu}g/ml$</TEX> 이상의 농도에서 90% 이상의 방제활성 보였다. 하지만 Phytophthora infestans에 의한 토마토 역병에 대해서는 전혀 항균활성이 없었다. 앞으로 B. cepacia EB215균을 이용한 미생물살균제 개발에 대하 연구를 진행할 예정이다. An endophytic bacterial strain EB215 that was isolated from cucumber (Cucumis sativus) roots displayed a potent in vivo antifungal activity against Colletotrichum species. The strain was identified as Burkholderia cepacia based on its physiological and biochemical characteristics, and 16S rDNA gene sequence. Optimal medium and incubation period for the production of antifungal substances by B. cepacia EB215 were nutrient broth (NB) and 3 days, respectively. An antifungal substance was isolated from the NB cultures of B. cepacia EB215 strain by centrifugation, n-hexane partitioning, silica gel column chromatography, preparative TLC, and in vitro bioassay. Its chemical structure was determined to be pyrrolnitrin by mass and NMR spectral analyses. Pyrrolnitrin showed potent disease control efficacy of more than 90% against pepper anthracnose (Colletotrichum coccodes), cucumber anthracnose (Colletotrichum orbiculare), rice blast (Magnaporthe grisea) and rice sheath blight (Corticium sasaki) even at a low concentration of <TEX>$11.1\;{\mu}g/ml$</TEX>. In addition, it effectively controlled the development of tomato gray mold (Botrytis cinerea) and wheat leaf rust (Puccinia recondita) at concentrations over <TEX>$33.3\;{\mu}g/ml$</TEX>. However, it had no antifungal activity against Phytophthora infestans on tomato plants. Further studies on the development of microbial fungicide using B. cepacia EB215 are in progress.

Characterization of antifungal glycoprotein in red-light-irradiated broadbean leaflets

Red-light treatment of broadbean leaflets resulted in the production of antifungal substance(s) against Botrytis cinerea. The antifungal substance(s) was positively charged, as the antifungal constituent was removed by the cation exchanger CM cellulose. Treatment of infection droplets with glycosidases (α-mannosidase, β-galactosidase, β-glucosidase), glycol-specific reagent periodate (NaIO4), and proteinase K completely eliminated antifungal activity, suggesting that both protein and carbohydrate are active components. The protein content of infection droplets was 0.148mg/ml. The HPLC gel column analysis of infection droplets resulted in four fractions; all the fractions showed antifungal activity.

Root‐colonizing Fungi from Oilseed Rape and their Inhibition of Verticillium dahliae

Root‐colonizing fungi obtained from thoroughly washed root segments of symptomless young oilseed rape plants growing in field soil were examined for their inhibitory effect on the wilt fungus, Verticillium dahliae Kleb. The isolated fungi that were possible to identify belonged to the different genera Trichoderma, Gliocladium, Mortierella, Fusarium and Alternaria. Oilseed rape seedlings from seeds exposed to both sporulating and nonsporulating fungal isolates were shown to be colonized by their hyphae in gnotobiotic conditions and the emergence/root growth was significantly affected in their presence. Inoculation with a few isolates not only covered the root surface but also seemed to extensively colonize the inner root cortical tissues partly by producing characteristic structures in the roots. All of these suppressed the pathogen in in vitro assays but the mode of suppression in most cases did not seem to be due to production of antifungal substances. In nonsterile field soil, several of the isolates conferred protection against V. dahliae by delaying symptom development. None of the isolates was shown to increase wilt symptoms. In addition to protection, two isolates, yet to be identified, also showed increased shoot dry weight compared with that of healthy controls. A majority of the isolates showed proteolytic activity whereas only three produced chitinolytic enzymes.Results for the isolates obtained by the method selected for this study could be considered as a starting point for evaluating antagonists capable of both competing for root colonization and preventing root infection, with the final aim being to achieve successful biological control of the wilt fungus.

Production of antifungal substance by Lactococcus lactis subsp. lactis CHD-28.3

Six of the 2100 colonies of lactic acid bacteria isolated from 4 month old Cheddar cheese and raw buffalo milk showed antifungal activity against Aspergillus flavus IARI when tested by the well agar diffusion assay on Potato Dextrose Agar containing 0.1% Triton X-100. Out of these, the most promising isolate having a broad spectrum of antifungal activity including Aspergillus flavus IARI, A. flavus NCIM 555, A. parasiticus NCIM 898 and Fusarium spp. was identified as Lactococcus lactis subsp. lactis CHD-28.3. Among the mold cultures used as indicator strains, the most sensitive towards antifungal substance produced by the test culture was A. flavus IARI. The cell-free supernatant of the test culture in Elliker's broth adjusted to pH 6.8 produced an inhibition zone of 15–19 mm against A. flavus IARI, A. flavus NCIM555 and A. parasiticus NCIM898. The isolate when grown at 30 °C for 48 h in Elliker's broth showed optimum antifungal activity. When the supernatant was neutralized to pH 7.0 or 7.5, there was little reduction in activity. However, after enzymatic treatment of supernatant with chymotrypsin, trypsin and pronase E, the antifungal activity disappeared which indicated the proteinaceous nature of the antifungal substance.

Rhizobacteria of maize antagonistic to Fusarium moniliforme, a soil-borne fungal pathogen: Colonization of rhizosphere and roots

Rhizobacteria of maize isolated from various soils with a long history of maize cultivation and which exhibited antagonism in vitro to Fusarium moniliforme were screened in a greenhouse for their ability to colonize maize roots. When used as seed coatings, the root “colonizing potential” of the antagonists differed significantly between strains and they also varied depending on the soil type used. For non-sterile soil, larger populations of the inoculant strain developed on maize roots growing in a Darling Downs vertisol than in a silty loam soil from Hawkesbury. However, the reverse was true when plants were grown in the silty loam Hawkesbury soil sterilized by γ-irradiation. The varying response to inoculation measured in both soils was apparently due to the diverse range of competing soil bacteria rather than the total microbial population per se. Of the 16 rhizobacteria screened for their colonizing ability, Pseudomonas cepacia strains 526 and 406 and Enterobacter agglomerans strain 621 formed consistently larger populations on the roots of both seedling and mature maize plants than the other strains. The seed inoculated P. cepacia strains were highly competitive and on 2 week old plants formed 10–80% of the total root-colonizing bacterial populations cultured on nutrient agar, and 1% after 2–3 months of plant growth. In montmorillonite soil, an inoculum density as low as 10 P. cepacia seed −1 resulted in 10 4 bacteria g −1 dry wt root. Nearly 70% of the P. cepacia strains tested were positive for pectinase and lipase activity. It is postulated that production of antifungal substances, rapid growth rates, the capacity to utilize a wide range of carbon sources exuded by maize roots and to a lesser extent the production of extracellular enzymes may facilitate P. cepacia strains to colonize maize roots.

Studies on environmental and nutritional factors on production of antifungal substance by Lactobacillus acidophilus R.

The optimal incubation temperature and period for the maximal production (27 units ml −1) of antifungal substance (AFS) by Lactobacillus acidophilus R. in Elliker's broth was 30°C and 48 h. Prolonged incubation led to diminished activity. The pH optima for the production of AFS ranged from 6·8 to 7·6, at which 24·16 units ml −1. of AFS were produced. Although incorporation o f yeast extract in the growth medium was stimulatory at 1·0%, beef extract and casamino acid stimulated AFS production at the level of 1·5%. Tryptone, on the other hand, was stimulatory at the level of 2·0%. Similarly, addition of glucose to the basal medium at the level of 0·5–1·0% enhanced the production of AFS (29 units ml −1). Beyond 2·0% it was inhibitory. There was an appreciable increase in production of AFS with the concomitant increase (0·5–3·5%) in the salt concentration in the growth medium. Calcium chloride was also stimulatory at the 0·1 % level, at which AFS production increased to 35 units ml −1. However, further increase in the calcium concentration was inhibitory. Contrary to this, magnesium chloride and manganese sulphate were stimulatory at low levels (0·02 and 0·005%, respectively).

Elicitor–like Substances Present in Barley and Wheat Seeds

Abstract Barley and wheat seeds contain elicitor–like substances which induce the production of antifungal substances in the host plants effective against powdery mildew fungi. Seed extract per se does not exhibit direct antimicrobial activity but induces the resistance response on the host. It also induces the systemic resistance in juvenile leaves. Host resistance induced by the treatment with seed extract shows some degree of cultivar specificity.

Seasonal variations in the production of antifungal substances by some dictyotales (brown algae) from the french mediterranean coast

Hexane extracts of some algae belonging to the Dictyotales collected over a 12 month period were tested for their antifungal activity using human pathogenic fungi (yeasts, moulds and dermatophytes) and phytopathogenic fungi responsible for diseases in Mediterranean plants and trees. The three algal species tested (Dictyota dichotoma, Dictyota dichotoma var. implexa, Dilophus spiralis) exhibited a wide spectrum of antifungal activity which varied during the seasons.

Nutritional Requirement for Production of Antifungal Substance by Enterobacter aerogenes and Bacillus subtilis Antagonists of Phytophthora cactorum1

AbstractAnker's medium with glucose and Thornton's medium were most suitable for growing Enterobacter aerogenes and Bacillus subtilis respectively, antagonists of P. cactorum, the causal agent of apple crown rot. Calcium nitrate was thebest source of nitrogen for growing cultures of E. aerogenes and B. subtilis. E. aerogenes produced the maximum amount of antifungal substance at 200 and 400 mg/l of nitrogen in the medium. Phosphate supplied either in the potassium or calcium form did not change the growth of either antagonist. An addition of 200 mg/l of N and 400 mg/l of P significantly enhanced the production of antifungal substance by E. aerogenes on Anker's medium with glucose. Thornton's medium supplemented with 200 mg/l of N and 100 mg/l of P produced the maximum amount of antifungal substance from B. subtilis. Generally, soil extracts without enrichment did not support the growth of either antagonist; E. aerogenes required at least 400 mg/lof, both N and P while B. subtilis required 200 mg/l of N and 800 mg/l of P for the maximum production of antifungal substance. When ammonium phosphate was added to soil extracts, only a small amount of antifungal substance was produced by E. aerogenes and none by B. subtilis. These results indicate that E. aerogenes and B. subtilis need N and P fertilization of the sterilized soil for the maximum production of the antifungal substance that inhibits the growth of P. cactorum.

Production of Antifungal Substances in the Soil Flooded with Fertilizer Solution

Production of Antifungal Substances in the Soil Flooded with Fertilizer Solution

Experimental COnditions Related to the Production of Antifungal Substances in Soil Flooded with Fertilizer Solution

Experimental COnditions Related to the Production of Antifungal Substances in Soil Flooded with Fertilizer Solution

Increases in peroxidase-and polyphenoloxidase-activities and production of antifungal substances in mulberry shoots following wounding or infection by pathogenic fungi.

Increases in peroxidase-and polyphenoloxidase-activities and production of antifungal substances in mulberry shoots following wounding or infection by pathogenic fungi.

Effect of certain physico-chemical factors on growth and antifungal property of Stachybotrys atra

Stachybotrys atra was found to utilize sucrose and asparagine as the best carbon and nitrogen sources. A temperature of 30°C and pH 5.6 was found to be optimum for its growth. The fungus secretes a dark brown to black thermostable toxic metabolite in the medium. Maximum production of antifungal substance was observed at 26°C and at pH 5.0 using maltose and sodium nitrate as the carbon and nitrogen sources. Importance of the metabolite produced by S. atra is discussed.

A technique for rapid demonstration of the production of antifungal substances by fungi or other microorganisms

A new technique is described for rapidly determining whether a mould or other micro-organism produces antifungal metabolic products. This requires the use of a small rectangular glass cell filled with agar of which one side is inoculated with the fungus under investigation and the other side is later inoculated with a standard test fungus.

Production of Antifungal and Antibacterial Substances by Fungi; Preliminary Examination of 166 Strains of Fungi Imperfecti

SUMMARY: One hundred and sixty-six strains of Fungi Imperfecti have been examined primarily for the production of antifungal substances, though antibacterial substances have also been sought in most cases. Antifungal substances were produced by several species of Aspergillus and Penicillium, Fusarium caeruleum, Metarrhizium glutinosum, Stachybotrys atra, Tri-choderma viride, Gliocladium catenulatum and Trichothecium roseum. Antibacterial substances were produced by species of Aspergillus, Fusarium, Penicillium, Stachybotrys and Trichoderma. The chemical nature of the substances responsible for this activity is known or can be suggested in some cases, but others are worthy of further investigation.