Journal of Microbiology

Journal Article

Antifungal activity of 3-acetylbenzamide produced by actinomycete WA23-4-4 from the intestinal tract of Periplaneta americana: Xia Fang , Juan Shen , Jie Wang , Zhi-li Chen , Pei-bin lin , Zhi-yu Chen , Lin-yan Liu , Huan-xiong Zeng , Xiao-bao Jin; J. Microbiol. 2018;56(7):516-523. Published online June 28, 2018; DOI: https://doi.org/10.1007/s12275-018-7510-z

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Abstract: Actinomycetes are well-known for producing numerous bioactive secondary metabolites. In this study, primary screening by antifungal activity assay found one actinomycete strain WA23-4-4 isolated from the intestinal tract of Periplaneta americana that exhibited broad spectrum antifungal activity. 16S rDNA gene analysis of strain WA23-4-4 revealed close similarity to Streptomyces nogalater (AB045886) with 86.6% sequence similarity. Strain WA23-4-4 was considered as a novel Streptomyces and the 16s rDNA sequence has been submitted to GenBank (accession no. KX291006). The maximum antifungal activity of WA23-4-4 was achieved when culture conditions were optimized to pH 8.0, with 12% inoculum concentration and 210 ml ISP2 medium, which remained stable between the 5th and the 9th day. 3-Acetyl benzoyl amide was isolated by ethyl acetate extraction of WA23- 4-4 fermentation broth, and its molecular formula was determined as C9H9NO2 based on MS, IR, 1H, and 13C NMR analyses. The compound showed significant antifungal activity against Candida albicans ATCC 10231 (MIC: 31.25 μg/ml) and Aspergillus niger ATCC 16404 (MIC: 31.25 μg/ml). However, the compound had higher MIC values against Trichophyton rubrum ATCC 60836 (MIC: 500 μg/ml) and Aspergillus fumigatus ATCC 96918 (MIC: 1,000 μg/ml). SEM analysis showed damage to the cell membrane of Candida albicans ATCC 10231 and to the mycelium of Aspergillus niger ATCC 16404 after being treatment with 3-acetyl benzoyl amide. In conclusion, this is the first time that 3-acetyl benzoyl amide has been identified from an actinomycete and this compound exhibited antifungal activity against Candida albicans ATCC 10231 and Aspergillus niger ATCC 16404.

Research Support, Non-U.S. Gov'ts

NOTE] Construction and Characterisation of an Antifungal Recombinant Bacillus thuringiensis with an Expanded Host Spectrum: Qin Liu , Jong Yul Roh , Yong Wang , Jae Young Choi , Xue Ying Tao , Jae Su Kim , Yeon Ho Je; J. Microbiol. 2012;50(5):874-877. Published online November 4, 2012; DOI: https://doi.org/10.1007/s12275-012-2201-7

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Abstract: A novel antifungal Bacillus thuringiensis strain 19–22, ssp. kurstaki (H3a3b3c), was characterised. This strain included cry1Aa, cry1Ab, cry1Ac, and cry1D, which have high insecticidal activities against lepidopteran larvae other than Spodoptera exigua. To expand the host spectrum, a cry1E gene whose product is active against S. exigua was introduced into the isolate. The transformant successfully expressed the Cry1E protein without any loss of its original antifungal activities. These results indicate that this recombinant strain exhibits dual activities and may be used as an integrated control agent to control plant diseases and insect pests.

Antifungal Activity of Leuconostoc citreum and Weissella confusa in Rice Cakes: Eunjong Baek , Hyojin Kim , Hyejung Choi , Sun Yoon , Jeongho Kim; J. Microbiol. 2012;50(5):842-848. Published online November 4, 2012; DOI: https://doi.org/10.1007/s12275-012-2153-y

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Abstract: The antifungal activity of organic acids greatly improves the shelf life of bread and bakery products. However, little is known about the effect of lactic acid fermentation on fungal contamination in rice cakes. Here, we show that lactic acid fermentation in rice dough can greatly retard the growth of three fungal species when present in rice cakes, namely Cladosporium sp. YS1, Neurospora sp. YS3, and Penicillium crustosum YS2. The antifungal activity of the lactic acid bacteria against these fungi was much better than that of 0.3% calcium propionate. We found that organic acids including lactic and acetic acid, which are byproducts of lactic fermentation or can be artificially added, were the main antifungal substances. We also found that some Leuconostoc citreum and Weissella confusa strains could be good starter species for rice dough fermentation. These results imply that these lactic acid bacteria can be applicable to improve the preservation of rice cakes.

NOTE] Antifungal Activity of Extracellular Hydrolases Produced by Autolysing Aspergillus nidulans Cultures: Melinda Szilágyi , Fruzsina Anton , Katalin Forgács , Jae-Hyuk Yu , István Pócsi , Tamás Emri; J. Microbiol. 2012;50(5):849-854. Published online November 4, 2012; DOI: https://doi.org/10.1007/s12275-012-2001-0

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Abstract: Carbon-starving Aspergillus nidulans cultures produce high activities of versatile hydrolytic enzymes and, among these, ChiB endochitinase and EngA β-1,3-endoglucanase showed significant antifungal activity against various fungal species. Double deletion of engA and chiB diminished the antifungal activity of the fermentation broths and increased conidiogenesis and long-term viability of A. nidulans, but decreased the growth rate on culture media containing weak carbon sources. Production of ChiB and EngA can influence fungal communities either directly due to their antifungal properties or indirectly through their effects on vegetative growth. Our data suggest saprophytic fungi as promising future candidates to develop novel biocontrol technologies.

Antifungal Activity and Mechanism of Fengycin in the Presence and Absence of Commercial Surfactin Against Rhizopus stolonifer: Yang Tao , Xiao-mei Bie , Feng-xia Lv , Hai-zhen Zhao , Zhao-xin Lu; J. Microbiol. 2011;49(1):146-150. Published online March 3, 2011; DOI: https://doi.org/10.1007/s12275-011-0171-9

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Abstract: The antifungal activity and mechanism of fengycin in the presence and absence of commercial surfactin against Rhizopus stolonifer were investigated. The MIC (minimal inhibitory concentration) of fengycin without commercial surfactin added was 0.4 mg/ml while the MIC of fengycin with commercial surfactin added was 2.0 mg/ml. Fengycin acted on cell membrane and cellular organs and inhibited DNA synthesis. The antifungal effect of fengycin was reduced after commercial surfactin was added. All these results suggest that the fungal cell membrane may be the primary target of fengycin action and commercial surfactin may reduce the antifungal activity of fengycin.

Isolation and Characterization of Antifungal Peptides Produced by Bacillus amyloliquefaciens LBM5006: Lisianne Brittes Benitez , Renata Voltolini Velho , Marcia Pagno Lisboa , Luis Fernando da Costa Medina , Adriano Brandelli; J. Microbiol. 2010;48(6):791-797. Published online January 9, 2011; DOI: https://doi.org/10.1007/s12275-010-0164-0

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Abstract: Bacillus amyloliquefaciens LBM 5006 produces antagonistic activity against pathogenic bacteria and phytopathogenic fungi, including Aspergillus spp., Fusarium spp., and Bipolaris sorokiniana. PCR analysis revealed the presence of ituD, but not sfp genes, coding for iturin and surfactin, respectively. The antimicrobial substance produced by this strain was isolated by ammonium sulfate precipitation, gel filtration chromatography and 1-butanol extraction. The ultraviolet spectrum was typical of a polypeptide and the infrared spectrum indicates the presence of peptide bonds and acyl group(s). The antimicrobial substance was resistant to proteolytic enzymes and heat treatment, and was reactive with ninhydrin. Mass spectroscopy analysis indicated that B. amyloliquefaciens LBM 5006 produces two antimicrobial peptides, with main peaks at m/z 1,058 Da and 1,464 Da, corresponding to iturin-like and fengycin-like peptides, respectively. B. amyloliquefaciens LBM 5006 showed significant activity against phytopatogenic fungi, showing potential for use as a biocontrol agent or production of antifungal preparations.

Endophytic Fungi Diversity of Aquatic/Riparian Plants and Their Antifungal Activity In Vitro: Hai-Yan Li , Chun-An Zhao , Chen-Jian Liu , Xiao-Fei Xu; J. Microbiol. 2010;48(1):1-6. Published online March 11, 2010; DOI: https://doi.org/10.1007/s12275-009-0163-1

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Abstract: Two hundred and fourteen endophytic fungi were isolated from 500 segments of aquatic/riparian plants Ottelia acuminata, Myriophyllum verticillatum, Equisetum arvense, Cardamine multijuga, and Impatiens chinensis. They were identified to 31 taxa in which Cladosporium, Fusarium, and Geotrichum were the dominant genera. Among all isolates, 169 (79%) were anamorphic fungi, 1 (0.5%) was an teleomorphic ascomycete and 44 (21%) were sterile mycelia. There were significant differences in the colonization frequency of endophytes between the five plant species (X~2=51.128, P<0.001, Chi-square test). The riparian plants harboured more endophytes than the submerged plants. The antifungal activity of these isolates against Fusarium solani and Phytophthora nicotianae in vitro were tested and 28 (13.1%) isolates showed antifungal activities with more than 30% growth inhibition rate against the two pathogens.

Antifungal Activities of the Essential Oils in Syzygium aromaticum (L.) Merr. Et Perry and Leptospermum petersonii Bailey and their Constituents against Various Dermatophytes: Mi-Jin Park , Ki-Seob Gwak , In Yang , Won-Sil Choi , Hyun-Jin Jo , Je-Won Chang , Eui-Bae Jeung , In-Gyu Choi; J. Microbiol. 2007;45(5):460-465.; DOI: https://doi.org/2589 [pii]

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Abstract: This study was carried out in order to investigate the potential of using plant oils derived from Leptospermum petersonii Bailey and Syzygium aromaticum L. Merr. Et Perry as natural antifungal agents. The antifungal effects of essential oils at concentrations of 0.05, 0.1, 0.15, and 0.2 mg/ml on the dermatophytes Microsporum canis (KCTC 6591), Trichophyton mentagrophytes (KCTC 6077), Trichophyton rubrum (KCCM 60443), Epidermophyton floccosum (KCCM 11667), and Microsporum gypseum were evaluated using the agar diffusion method. The major constituents of the active fraction against the dermatophytes were identified by gas chromatography-mass spectrometry and high-performance liquid chromatography analysis. The antifungal activities of S. aromaticum oil (clove oil) against the dermatophytes tested were highest at a concentration of 0.2 mg/ml, with an effectiveness of more than 60%. Hyphal growth was completely inhibited in T. mentagrophytes, T. rubrum, and M. gypseum by treatment with clove oil at a concentration of 0.2 mg/ml. Eugenol was the most effective antifungal constituent of clove oil against the dermatophytes T. mentagrophytes and M. canis. Morphological changes in the hyphae of T. mentagrophytes, such as damage to the cell wall and cell membrane and the expansion of the endoplasmic reticulum, after treatment with 0.11 mg/ml eugenol were observed by transmission electron microscopy (TEM). At a concentration of 0.2 mg/ml, L. petersonii oil (LPO) was more than 90% effective against all of the dermatophytes tested, with the exception of T. rubrum. Geranial was determined to be the most active antifungal constituent of L. petersonii oil. Taken together, the results of this study demonstrate that clove and tea tree oils exhibited significant antifungal activities against the dermatophytes tested in this study.

Journal Article

A Putative Early Response of Antifungal Bacillus lentimorbus WJ5 Against the Plant Pathogenic Fungus, Colletotrichum gloeosporioides, Analyzed by a DNA Microarray: Young-Keun Lee , Yu-Sin Jang , Hwa-Hyoung Chang , Hye-Young Chung , Seok Won Hyung , Hye-Young Chung; J. Microbiol. 2005;43(3):308-312.; DOI: https://doi.org/2208 [pii]

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Abstract: The global RNA transcription profiles of Bacillus lentimorbus WJ5 under an in vitro co-culture with Colletotrichum gloeosporioides were analyzed in order to study the antagonistic bacteria-fungi interactions. Using a filter membrane system, B. lentimorbus WJ5 was exposed to the spores of C. gloeosporioides at the late exponential stage. The transcription profiles of the B. lentimorbus WJ5, both with and without a challenge from C. gloeosporioides, were analyzed using custom DNA chips containing 2,000 genome fragments. A total of 337 genes were expressed, with 87 and 47 up- and down-regulated, respectively. Of these, 12 genes, which were involved in central carbon metabolisms, and 7 from minor catabolism were relatively highly up-regulated (> 10 fold) and down-regulated (< 0.2 fold), respectively. Nine genes, which were thought to be related to the antifungal activity, were also up-regulated, but their levels were not so high (2.0 - 9.7 folds). From the results, during the early stage of the co-culture of B. lentimorbus WJ5 and C. gloeosporioides, nutrient competition seemed to occur; therefore, the genes from central carbon metabolisms could be up-regulated, while those from minor catabolism could be down-regulated.

Antifungal activities of peptides with the sequence 10-17 of magainin 2 at the N-termini against aspergillus fumigatus: Lee, Myung Kyu , Lee, Dong Gun , Shin, Song Yub , Lee, Sung Gu , Kang, Joo Hyun , Hahm, Kyung Soo; J. Microbiol. 1996;34(3):274-278.

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Abstract: Two peptides, MA-inv AND MA-ME, with the sequence 10-17 of maganin 2 at their-N-termini were designed and synthesized. The peptides had higher antifungal activities against Aspergilus fumigatus without hemolytic activities. The minimal inhibition concentratory (MIC) values of both peptides against A. fumigatus were 5 ㎍/ml, whereas those of the native peptides, magainin 2 and melittin, were 10㎍/ml. At 3 ㎍/ml, MA-inv and MA-ME inhibited the mycelium growth of A. fumigatus by 94.6% and 97.3% respectively, whereas magainin 2 and melittin inhibited by 62.2% and 32.4, respectively. MA-inv showed up to 80% inhibition of (1, 3)-β-D-glucan synthase activity of A. fumigatus. The peptides also showed up to 80% inhibition of (1, 3)-β-D glucan synthase activity of A. fumigatus. The peptides also showed antifungal activities for other fungi of Aspergillus sp. However, the antibiotic activities of MA-ME against Escherichia coli, Bacillus subtilis and Fusarium oxysporum were more effective than those of MA-inv, suggesting that the C-terminal sequences of MA-inv and MA-ME may also influence their antibiotic activities. These results suggest that the N-terminal sequence of the designed peptides, KKFGKAFV, is important for their antifungal activities against A. fumigatus and their C- terminal sequences are related to the organism selectivity.

Structure-antifungal activity relationships of cecropin a hybrid peptides against trichoderma sp.: Shin, Song Yub , Lee, Dong Gun , Lee, Sung gu , Kim, Kil Lyong , Lee, Myung Kyu , Hahm, Kyung Soo; J. Microbiol. 1997;35(1):21-24.

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Abstract: The hybrid peptides, CA-ME, CA-MA and CA-BO, with the N-terminal sequence 1-8 of cecropin A and the N-terminal sequences 1-12 of melittin, magainin 2 and bombinin, respectively, have more improved antibacterial activities. CA-MA was found to have stronger antifungal activity against Trichoderma sp than other hybrid peptides and their parental peptides. In order to elucidate the relationships between the peptide structure and antifungal activity, several analogues of CA-MA or CA-BO were also designed and synthesized by the solid phase method. Antifungal activity was measured against T. reesei and T. viride, and hemolytic activity was measured by a solution method against human red blood cells. The residue 16 of CA-MA, Ser, was found to be important for antifungal activity. When the residue was substituted with Leu, showed powerful antifungal activity was dramatically decreased. CA-MA, P1, P4 and P5 designed in this study showed powerful antifungal activity against T. reesei and T. viride with low hemolytic activity against human red blood cells. These hybrid peptides will be potentially useful model to further design peptides with powerful antifungal activity for the effective therepy of fungal infection and understand the mechanisms of antifungal actions of hybrid peptides.

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