scholarly journals Screening of Bacillus velezensis E2 and the Inhibitory Effect of Its Antifungal Substances on Aspergillus flavus

Foods ◽  
2022 ◽  
Vol 11 (2) ◽  
pp. 140
Author(s):  
Shengjie Li ◽  
Xingang Xu ◽  
Tianyuan Zhao ◽  
Jianing Ma ◽  
Luning Zhao ◽  
...  

Aspergilus flavus is the main pathogenic fungus that causes food mold. Effective control of A. flavus contamination is essential to ensure food safety. The lipopeptides (LPs) produced by Bacillus strains have been shown to have an obvious antifungal effect on molds. In this study, an antagonist strain of Bacillus velezensis with obvious antifungal activity against A. flavus was isolated from the surface of healthy rice. Using HPLC-MS analysis, the main components of LPs produced by strain E2 were identified as fengycin and iturins. Further investigations showed that LPs could inhibit the spore germination, and even cause abnormal expansion of hyphae and cell rupture. Transcriptomic analyses showed that some genes, involved in ribosome biogenesis in eukaryotes (NOG1, KRE33) and aflatoxin biosynthesis (aflK, aflR, veA, omtA) pathways in A. flavus were significantly down-regulated by LPs. In conclusion, this study provides novel insights into the cellular and molecular antifungal mechanisms of LPs against grain A. flavus contamination.

2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Ping Zhang ◽  
Jian Diao ◽  
Guangqiang Xie ◽  
Ling Ma ◽  
Lihai Wang

An endophytic bacterium Bacillus velezensis BY6 was isolated from the wood stems of healthy Populus davidiana × P. alba var. pyramidalis (PdPap). The BY6 strain can inhibit pathogenic fungus Alternaria alternate in PdPap and promote growth of PdPap seedlings. In the present study, we used the Pacific Biosciences long-read sequencing platform, a single-molecule real-time (SMRT) technology for strain BY6, to perform complete genome sequencing. The genome size was 3,898,273 bp, the number of genes was 4,045, and the average GC content was 47.33%. A complete genome of strain BY6 contained 110 secondary metabolite gene clusters. Nine of the secondary metabolite gene clusters exhibited antifungal activity and promoted growth functions primarily involved in the synthesis of surfactin, bacteriocins, accumulated iron ions, and related antibiotics. Gene clusters provide genetic resources for biotechnology and genetic engineering, and enhance understanding of the relationship between microorganisms and plants.


Author(s):  
Daniel Chavarría-Bolaños ◽  
Vicente Esparza-Villalpando ◽  
Karol Ramírez

Chlorhexidine was introduced almost seven decades ago and has a myriad of applications in dentistry. Few studies have evaluated the antimicrobial and antifungal capacity of different concentrations of chlorhexidine mouthwashes. Therefore, the aim of this study, was to evaluate in vitro, the antibacterial and antifungal capacity of three commercially available mouthwashes in Costa Rica, with different concentrations of chlorhexidine, 0.12%, 0.06%, and 0.03%. The experimental method selected was the Kirby-Bauer method to evaluate the antibacterial and antifungal effect of each compound by measuring the inhibitory effect on Staphylococcus aureus, Enterococcus faecalis, Escherichia coli, and Candida albicans strains, exposed to the antiseptic solutions. All samples showed some degree of antibacterial and antifungal effect. Even though we provide in vitro results, our findings are of relevance since all the species used in our experiment are microorganisms that may be present in dental plaque. Our results further support evidence that oral hygiene regimens may include mouthwashes with low doses of chlorhexidine and maintain reasonable antibacterial and antifungal efficacy.


Author(s):  
Tomojiro Koide ◽  
Muneaki Tamura

Abstract The antifungal effect of diglyceryl dicaprylate (DGDC), one of the emulsifiers used as a food additive, on Candida albicans which is a pathogenic fungus that is predominant in the oral cavity was investigated. This component did not affect C. albicans growth, however, it suppressed some virulence factors in a concentration-dependent manner. Furthermore, the suppression of pathogenic factors, such as biofilm formation, adhesion, highly pathogenic dimorphism, and ability to produce proteolytic enzymes was due to reduction in mRNA expression levels of genes involved in fungal pathogenicities. From these results, this emulsifier could potentially prevent the development of intraoral and extraoral diseases involving C. albicans and could potentially use in oral care and improvement of quality of life.


2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Daniil N. Olennikov ◽  
Nina I. Kashchenko

An ethanolic extract and its ethyl acetate-soluble fraction from leaves ofCalendula officinalisL. (Asteraceae) were found to show an inhibitory effect on amylase. From the crude extract fractions, one new phenolic acid glucoside, 6′-O-vanilloyl-β-D-glucopyranose, was isolated, together with twenty-four known compounds including five phenolic acid glucosides, five phenylpropanoids, five coumarins, and nine flavonoids. Their structures were elucidated based on chemical and spectral data. The main components, isoquercitrin, isorhamnetin-3-O-β-D-glucopyranoside, 3,5-di-O-caffeoylquinic acid, and quercetin-3-O-(6′′-acetyl)-β-D-glucopyranoside, exhibited potent inhibitory effects on amylase.


Toxins ◽  
2019 ◽  
Vol 11 (3) ◽  
pp. 156 ◽  
Author(s):  
Aoyu Li ◽  
Huahua Yu ◽  
Rongfeng Li ◽  
Song Liu ◽  
Ronge Xing ◽  
...  

Jellyfish envenomations result in extensive dermatological symptoms, clinically named as jellyfish dermatitis, which can seriously affect the daily activities and physical health of people. Inflammatory response accompanies the whole process of jellyfish dermatitis and the complexity of jellyfish venom components makes it difficult to treat jellyfish dermatitis symptoms effectively. Moreover, inhibiting inflammation is essential for the treatment of jellyfish stings and exploring the main components of jellyfish venom that cause inflammation is an urgent research area. In this study, the inhibitory effects of matrix metalloproteinase (MMP) inhibitors for venom-induced inflammation were explored at a cellular level. The expression of the three inflammatory factors, IL-6, TNF-α and MCP-1 in two skin cell lines, human keratinocyte cells (HaCaT) and human embryonic skin fibroblasts cells (CCC-ESF-1), at the cellular level, after treatment with the inhibitors of jellyfish Nemopilema nomurai (N. nomurai) nematocyst venom (NnNV-I), were determined. The results showed that inhibitors of MMP can significantly reduce the toxic effects of jellyfish Nemopilema nomurai nematocyst venom (NnNV) to skin cells. The expression levels of the three inflammatory factors IL-6, MCP-1, and TNF-α in the cells were also significantly decreased, indicating that MMPs in jellyfish venom are probably vital factors leading to jellyfish dermatitis. This study is beneficial in the prevention and treatment of jellyfish stings.


Aquaculture ◽  
2020 ◽  
Vol 523 ◽  
pp. 735165 ◽  
Author(s):  
Xixi Li ◽  
Xiaojian Gao ◽  
Shuangming Zhang ◽  
Ziyan Jiang ◽  
Hui Yang ◽  
...  

2020 ◽  
Vol 86 (11) ◽  
Author(s):  
Xuefa Chong ◽  
Chenyu Wang ◽  
Yao Wang ◽  
Yixiao Wang ◽  
Liyuan Zhang ◽  
...  

ABSTRACT Fusarium graminearum, the main pathogenic fungus causing Fusarium head blight (FHB), produces deoxynivalenol (DON), a key virulence factor, which is synthesized in the endoplasmic reticulum (ER). Sey1/atlastin, a dynamin-like GTPase protein, is known to be required for homotypic fusion of ER membranes, but the functions of this protein are unknown in pathogenic fungi. Here, we characterized Sey1/atlastin homologue FgSey1 in F. graminearum. Like Sey1/atlastin, FgSey1 is located in the ER. The FgSEY1 deletion mutant exhibited significantly reduced vegetative growth, asexual development, DON biosynthesis, and virulence. Moreover, the ΔFgsey1 mutant was impaired in the formation of normal lipid droplets (LDs) and toxisomes, both of which participate in DON biosynthesis. The GTPase, helix bundle (HB), transmembrane segment (TM), and cytosolic tail (CT) domains of FgSey1 are essential for its function, but only the TM domain is responsible for its localization. Furthermore, the mutants FgSey1K63A and FgSey1T87A lacked GTPase activity and failed to rescue the defects of the ΔFgsey1 mutant. Collectively, our data suggest that the dynamin-like GTPase protein FgSey1 affects the generation of LDs and toxisomes and is required for DON biosynthesis and pathogenesis in F. graminearum. IMPORTANCE Fusarium graminearum is a major plant pathogen that causes Fusarium head blight (FHB) of wheats worldwide. In addition to reducing the plant yield, F. graminearum infection of wheats also results in the production of deoxynivalenol (DON) mycotoxins, which are harmful to humans and animals and therefore cause great economic losses through pollution of food products and animal feed. At present, effective strategies for controlling FHB are not available. Therefore, understanding the regulation mechanisms of fungal development, pathogenesis, and DON biosynthesis is important for the development of effective control strategies of this disease. In this study, we demonstrated that a dynamin-like GTPase protein Sey1/atlastin homologue, FgSey1, is required for vegetative growth, DON production, and pathogenicity in F. graminearum. Our results provide novel information on critical roles of FgSey1 in fungal pathogenicity; therefore, FgSey1 could be a potential target for effective control of the disease caused by F. graminearum.


2019 ◽  
Vol 79 (1) ◽  
pp. 127-132
Author(s):  
F. C. Pontes ◽  
V. C. P. Abdalla ◽  
M. Imatomi ◽  
L. F. G. Fuentes ◽  
S. C. J. Gualtieri

Abstract In recent years, natural products with antifungal and antioxidant activities are being increasingly researched for a more sustainable alternative to the chemicals currently used for the same purpose. The plant pathogenic fungus Alternaria alternata is a causative agent of diseases in citrus, leading to huge economic losses. Antioxidants are important for the production of medicines for various diseases that may be related to the presence of free radicals, such as cancer, and in the cosmetic industry as an anti-aging agent and the food industry as preservatives. This study evaluated the antifungal and antioxidant potential of extracts of mature leaves of Myrcia splendens, a tree species that occurs in the Brazilian Cerrado. The antioxidant potential was analyzed by an assay of 1,1-diphenyl-2-picrylhydrazyl radical-scavenging method, and the antifungal activity was assessed through the evaluation of mycelial growth. Majority of the extracts exhibited a strong antioxidant activity, especially the acetonic extract (4A). The antioxidant activity may be related to the presence of phenolic compounds. However, the extracts showed no inhibitory activity of mycelial growth of the fungus tested, with the exception of dichloromethanic extract (2B), which had an inhibitory effect (10.2%) at the end of testing.


2021 ◽  
Vol 28 (2) ◽  
pp. 152
Author(s):  
Nampiah Sukarno ◽  
Rohani Cinta Badia Ginting ◽  
Utut Widyastuti ◽  
Latifah Kosim Darusman ◽  
Sihegiko Kanaya ◽  
...  

The medicinal plants Centella asiatica, Curcuma xanthorrhiza, Guazuma ulmifolia, and Hydrocotyle verticillata are widely used  in Indonesian traditional medicine, but little is known about their associated endophytic fungi. This research aimed to study the diversity of endophytic fungi derived from functional parts of these plants and to evaluate their potential as antifungal agents against the plant pathogenic fungus Fusarium oxysporum. A total of 17 isolates of endophytic fungi were obtained: nine from leaves of G. ulmifolia, three each from leaves of C. asiatica and H. verticillata, and two from rhizomes of C. xanthorrhiza. The genus Colletotrichum was found in all plants studied, but each plant was associated with different species. Colletotrichum aeschynomenes was associated with C. xanthorrhiza, C. siamense was associated with C. asiatica, and C. tropicale was associated with G. ulmifolia and H. verticillata. The species Curvularia affinis, Diaporthe tectonae, Lasiodiplodia mahajangana, Parengyodontium album, Talaromyces trachyspermus, and Speiropsis pedatospora were found only in G. ulmifolia; while Didymella coffeae-arabicae and Muyocopron laterale were found only in H. verticillata. The endophytic fungi showed inhibition activity against F. oxysporum with inhibition values of 6.0-78.9%, T. trachyspermus JBd10 and C. affinis JBd14 gave the highest inhibition activity.


2020 ◽  
Vol 12 (1) ◽  
pp. 90-99
Author(s):  
Matthew O. ADEBOLA ◽  
Tunde S. BELLO ◽  
Esther A. SERIKI ◽  
Mariam B. AREMU

Irish potato (Solanum tuberosum) is an important worldwide food crop and one of the most popular in Nigeria. Its abundance and successful yield have been immensely affected by black scurf disease caused by Rhizoctonia solani. Harnessing a cost-effective management of this pathogenic fungus, three botanical species Acalypha wilkesiana, Moringa oleifera and Carica papaya leaves, each at concentrations of 0 mg ml-1 (control), 25 mg ml-1, 50 mg ml-1 and 75 mg ml-1 were evaluated in vitro. The plant leaf extracts were prepared using methanol and were evaluated for their toxicity using agar well diffusion method. The fungus was isolated from spoilt Irish potato with black scurf symptoms. The results showed the presence of some phytochemicals in leaf extract of each of the plants tested. The three leaves extract independently inhibited mycelial growth of R. solani. The potency of all the plant extracts increased with the increase in concentration. The highest concentration (75 mg ml-1) of M. oleifera and C. papaya evaluated, gave the highest inhibitory effect of 0.81 mm and 1.63 mm respectively, which were not significantly different (p> 0.05), but was obviously different from A. wilkesiana (2.81 mm). Furthermore, M. oleifera extract gave the highest percentage of mycelial growth inhibition of the fungus in all grades of the concentrations evaluated, whereas A. wilkesiana showed the least. The leaves of the three species are therefore recommended for in vivo control of this fungus, owing to their proven efficacy and to their cheap availability.


Sign in / Sign up

Export Citation Format

Share Document