Antifungal activity of streptavidin C1 and C2 against pathogens causing Fusarium wilt

Fusarium wilt is caused by the soil-inhabiting fungus Fusarium oxysporum ff. spp. and is one of the most devastating plant diseases, resulting in losses and decreasing the quality and safety of agricultural crops. We recently reported the structures and biochemical properties of two biotin-binding proteins, streptavidin C1 and C2 (isolated from Streptomyces cinnamonensis strain KPP02129). In the present study, the potential of the biotin-binding proteins as antifungal agent for Fusarium wilt pathogens was investigated using recombinant streptavidin C1 and C2. The minimum inhibitory concentration of streptavidin C2 was found to be 16 µg ml^–1 for inhibiting the mycelial growth of F. oxysporum f.sp. cucumerinum and F. oxysporum f.sp. lycopersici, while that of streptavidin C1 was found to be 64 µg ml^–1. Compared with the nontreated control soil, the population density of F. oxysporum f.sp. lycopersici in the soil was reduced to 49·5% and 39·6% on treatment with streptavidin C1 (500 µg ml^–1) and C2 (500 µg ml^–1), respectively. A greenhouse experiment revealed that Fusarium wilt of tomato plants was completely inhibited on soil drenching using a 50-ml culture filtrate of the streptavidin-producing strain KPP02129.     

Antifungal activity of sesquiterpene lactones

Forty-five sesquiterpene lactones were screened for their antifungal activities against Microsporum cookei, Trichophyton mentagrophytes and Fusarium sp. The screening tests showed that a majority of sesquiterpene examined possess at least weak antifungal activity, the eudesmanolides being the most active. The antifungal activity of sesquiterpene lactones cannot be explained by the presence or absence of two potential active sites (the exocyclic methylene and, in pseudoguaianolides, a β-unsubstituted cyclopentenonel) but other functions must play a role in enhancing or reducing this activity.     

Antifungal potentiality of some plant extracts against Fusarium sp.

Abstract

Aqueous extracts of 46 plants belonging to 32 different families of the plant kingdom were screened for antifungal activity against eight important species of Fusarium viz., Fusarium equiseti, F. moniliforme, F. semitectum, F. graminearum, F. oxysporum, F. proliferatum, F. solani and F. lateritium. The test fungi were isolated from maize, paddy and sorghum seeds collected from Mysore district, Mysore, India. Among the several plants screened only 12 plants have recorded significant antifungal activity. The antifungal activity of aqueous extracts varied among the test pathogens and was compared with that of the synthetic fungicides Blitox, Captan, Dithane M-45 and Thiram. F. proliferatum, which showed high susceptibility for the aqueous extracts, was tested using different solvent extracts viz., petroleum ether, benzene, chloroform, methanol and ethanol extracts of all the 12 plants. The results revealed that these plants could be exploited for ecofriendly management of the diseases caused by the test fungal pathogens and seed biodeterioration during storage.     

Bikaverin and fusaric acid from Fusarium oxysporum show antioomycete activity against Phytophthora infestans

Aims: To isolate and identify antioomycete substances from Fusarium oxysporum EF119 against Phytophthora infestans and to investigate their antimicrobial activities against various plant pathogenic bacteria, oomycetes and true fungi. Methods and Results: Two antioomycete substances were isolated from liquid cultures of F. oxysporum EF119, which shows a potent disease control efficacy against tomato late blight caused by P. infestans. They were identified as bikaverin and fusaric acid by mass and nuclear magnetic resonance spectral analyses. They inhibited the mycelial growth of plant pathogenic oomycetes and fungi. Fusaric acid also effectively suppressed the cell growth of various plant pathogenic bacteria, but bikaverin was virtually inactive. Treatment with bikaverin at 300 μg ml^?1 suppressed the development of tomato late blight by 71%. Fusaric acid provided effective control against tomato late blight and wheat leaf rust over 67% at concentrations more than 100 μg ml^?1. Conclusions: Both bikaverin and fusaric acid showed in vitro and in vivo antioomycete activity against P. infestans. Significance and Impact of the Study: Fusarium oxysporum EF119 producing both bikaverin and fusaric acid may be used as a biocontrol agent against tomato late blight caused by P. infestans.     

中药提取物对酵母菌抗真菌活性研究

目的探讨6味中药2种方法提取成分对酵母菌的抑菌和杀菌作用。方法采用药基琼脂稀释法,测定6味中药水提和醇提成分对白念珠菌和糠秕马拉色菌的MIC和MFC。结果对白念珠菌：水提黄连、醇提黄柏、醇提土槿皮MIC范围分别为0．625—1．25mg／mL、0．625～1．25mg/mL、0．313—0．625mg／mL;均值均为0．625mg／mL;对糠秕马拉色菌：水提和醇提黄连MIC范围分别为0．625～1．25mg／mL和1．25mg／mL,均值均为1．25mg／mL。对白念珠菌：醇提土槿皮MFC范围0．625～2．5mg/mL,均值0．625rag／mL。结论水提黄连、醇提黄柏和土槿皮对白念珠菌有较强抑菌作用,其中醇提土槿皮有较强杀菌作用。水提和醇提黄连对糠秕马拉色菌有较强抑菌作用。     

Antifungal effect of Penicillium metabolites against some fungi

Microorganisms are increasingly exploited as a source of new biological control agents. Genus Penicillium is a source of novel bioactive molecules which can be used as antifungal agents. The objective of this study was to evaluate the antifungal potential of Penicillium strains. Culture filtrates of two Penicillium species were tested for their antifungal potential by well diffusion assays. Filtrate of Penicillium isolates showed high antifungal effects on mycelial growth of Fusarium oxysporum, Fusarium solani, Macrophomina phaseolina, Aspergillus japonicus var aculeatus and Cladosporium cladosporioides. But Penicillium italicum inhibit the fungal growth from 45 to 68% as compared to Penicillium simplissimum (25–68%). However in case of A. japonicus var aculeatus, Penicillium spp. extracts were equally effective and reduce the colony growth up to 68%. However, P. simplissimum extract was least effective in case of M. phaseolina, where it decreased the colony growth only 25%.     

Antifungal activity of six Saudi medicinal plant extracts against five phyopathogenic fungi

Six medicinal plants such as Amaranthus spinosus, Barbeya oleoides, Clutia lanceolata, Lavandula pubescens, Maerua oblongifolia and Withania somnifera collected from different locations in the southwestern part of Saudi Arabia were tested for antifungal activities against five plant pathogenic fungi causing serious diseases of vegetable crops. These fungi were Alternaria brassicae, Alternaria solani, Botrytis fabae, Fusarium solani and Phytophthora infestans. Aqueous plant extracts reduced mycelial growth and inhibited spore germination of all fungi tested. It is clear that the aqueous extract of Lavandula pubescens leaves was the best for controlling all phytopathogenic fungi under study. These results suggested that medicinal plant extracts play an important role in controlling the phytopathogenic fungi.     

Antifungal activity of cinnamaldehyde and eugenol congeners against wood-rot fungi

In this study, the antifungal activities of cinnamaldehyde and eugenol congeners against white-rot fungus Lenzites betulina and brown-rot fungus Laetiporus sulphureus were evaluated and the relationships between the antifungal activity and the chemical structures were also examined. Results from antifungal tests revealed that cinnamaldehyde, alpha-methyl cinnamaldehyde, (E)-2-methylcinnamic acid, eugenol and isoeugenol exhibited strong antifungal activity against all fungi tested. Results derived from the chemical structure-antifungal activity relationship study suggested that compounds with an aldehyde group or an acid group, a conjugated double bond and a length of CH chain outside the ring affect their antifungal properties. Furthermore, the presence of the methyl moiety in the ortho position may have a considerable influence on the inhibitory action against L. betulina and L. sulphureus. In addition, the lipophilicity may play, in part, a crucial role in determining the toxicity of phenylpropenes.     

纳米银对小麦赤霉病菌的抑制

采用化学还原法制备纳米银,以小麦赤霉病菌为受试菌株,研究纳米银对小麦赤霉病菌抗菌活性、对细胞内3种保护酶:超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)活性和对细胞渗透调节物质:丙二醛(MDA)、可溶性蛋白、可溶性糖含量的影响。结果表明:纳米银能显著抑制小麦赤霉病菌的生长,抑制作用随着浓度的增加而不断增大,10μg/mL的纳米银对病原菌的抑制率达90%以上,有效中浓度(EC_(50))为0.59μg/mL。随着纳米银处理时间(2、4、6、8和10 h)的增长,3种酶的活性均出现先增加后降低的变化。SOD、POD和CAT均在4 h出现最高值,10 h降至最低。纳米银使得菌体内丙二醛含量增加,可溶性蛋白和可溶性糖含量降低。纳米银破坏了病原真菌体内细胞的完整性,这可能是纳米银抑制病原菌生长的机理之一。     

Antifungal activity of lichen compounds against dermatophytes: a review

The growth rate inhibition of dermatophytes by compounds extracted by acetone, ethanol, methanol and water derived from representatives of several lichen genera (e.g. Caloplaca, Everniastrum, Heterodermia, Hypotrachyna, Platismatia and Ramalina) were compared on the basis of a worldwide review of published research. The examined dermatophytes included Epidermophyton floccosum, Microsporum audouinii, M. canis, M. gypseum, M. nanum, Trichophyton longifusus, T. mentagrophytes, T. rubrum, T. tonsurans and T. violaceum. The influence of selected secondary lichen compounds, for example, usnic acid, on the growth rates of these dermatophytes was also reviewed. The measurement of inhibition by lichen compounds was performed by several methods, but mostly those employing disc diffusion, broth dilution and agar dilution. The fungicidal activity of water-extracted compounds from Heterodermia leucomela and Hypotrachyna cirrhata and of methanol-extracted compounds from Evernia divaricata and Ramalina pollinaria, as well as protolichesterinic and 2-hydroxy-4-methoxy-3,6-dimethylbenzoic acids, are distinguished.     

Antifungal activity of soybean and chickpea isoflavones and their reduced derivatives

The fungicidal activity of the isoflavones from soybean (Glycine max) and chickpea (Cicer arietinum) has been studied on three food and forage contaminating fungi, Aspergillus ochraceus, Penicillium digitatum and Fusarium culmorum. The reduced derivatives of the corresponding isoflavones—the isoflavanones and the isoflavans—were also included in the investigation. For the first time in a comparative study it is shown that isoflavones and isoflavanones are variable in their activity whereas the isoflavans are moderately active inhibitors of fungal growth.     

低温胁迫诱导肺形侧耳合成麦角甾醇的通路分析

本文以肺形侧耳栽培菌株X57为研究对象,对其低温胁迫时期进行转录组分析,发现差异基因显著地富集到麦角甾醇合成通路。根据麦角甾醇合成通路的相关信息,在肺形侧耳中筛选出该通路的17个基因,并推测了肺形侧耳的麦角甾醇合成通路。利用荧光定量研究了X57栽培袋在低温处理下该通路上各个基因的表达,结果显示随着低温胁迫时间的增加,该通路上大部分基因的表达量持续上升,且差异显著。检测栽培袋中菌丝麦角甾醇含量发现,低温胁迫显著提高麦角甾醇的含量,与RNA‐Seq分析结果一致。此外,以无需打冷也能整齐出菇的野生菌株X1为对照,比较X57与X1的麦角甾醇基因对冷胁迫的响应情况,探究麦角甾醇合成通路是否在肺形侧耳低温诱导形成原基时期具有关键性作用。将X57与X1菌株置于PDA平板上培养并进行低温胁迫,利用荧光定量PCR对各个基因表达进行验证,结果显示两个菌株的麦角甾醇合成通路相关基因均对低温胁迫有响应,X57低温胁迫时通路中绝大多数基因的表达量上升,且大部分基因表达量提高2倍以上;X1菌株的通路中的表达量变化较小。由此推测麦角甾醇通路在肺形侧耳变温结实中低温刺激形成原基有一定作用,为深入研究肺形侧耳低温胁迫调控分子机理提供了重要的基础。     

Antifungal activity of Juniperus essential oils against dermatophyte, Aspergillus and Candida strains

AIMS: The increasing resistance to antifungal compounds and the reduced number of available drugs led us to search therapeutic alternatives among aromatic plants and their essential oils, empirically used by antifungal proprieties. In this work the authors report on the antifungal activity of Juniperus essential oils (Juniperus communis ssp. alpina, J. oxycedrus ssp. oxycedrus and J. turbinata). METHODS AND RESULTS: Antifungal activity was evaluated by determination of MIC and MLC values, using a macrodilution method (NCCLS protocols), on clinical and type strains of Candida, Aspergillus and dermatophytes. The composition of the oils was ascertained by GC and GC/MS analysis. All essential oils inhibited test dermatophyte strains. The oil from leaves of J. oxycedrus ssp. oxycedrus is the most active, with MIC and MLC values ranging from 0.08-0.16 microl ml(-1) to 0.08-0.32 microl ml(-1), respectively. This oil is mainly composed of alpha-pinene (65.5%) and delta-3-carene (5.7%). CONCLUSIONS: J. oxycedrus ssp. oxycedrus leaf oil proved to be an emergent alternative as antifungal agent against dermatophyte strains. delta-3-Carene, was shown to be a fundamental compound for this activity. SIGNIFICANCE AND IMPACT OF THE STUDY: Results support that essential oils or some of their constituents may be useful in the clinical management of fungal infections, justifying future clinical trials to validate their use as therapeutic alternatives for dermatophytosis.