scholarly journals Evaluation of the antifungal activity of marine actinomycetes isolates against the phytopathogenic fungi Colletotrichum siamense KA: A preliminary study for new antifungal compound discovery

Pharmacia ◽  
2021 ◽  
Vol 68 (4) ◽  
pp. 837-843
Author(s):  
Qonita Gina Fadhilah ◽  
Iman Santoso ◽  
Andi Eko Maryanto ◽  
Sarini Abdullah ◽  
Yasman Yasman

Marine actinomycetes are being explored to discover potential actinomycetes that produce antifungal compounds. In a previous study, marine actinomycetes isolates from the mangrove ecosystem were found to inhibit growth of the phytopathogenic fungi Colletotrichum siamense KA. In this study, the three of these isolates with the highest antagonistic activity—SM11, SM14, and SM15—were evaluated for their antifungal activity using antibiosis assay. The fermentation was performed in SCB:PDB medium (1:1) for 6, 9, and 12 days. The results showed that SM14 was the strongest potential isolate; it inhibited the growth of C. siamense KA on average up to 64.90% for 12 days on PDA filtrate medium. Molecular identification showed SM14 was closely related to Streptomyces sanyensis, but had differences in morphological and biochemical characteristics compared to SM11 or SM15. This indicated that the three isolates were different strains and may challenge further research on identifying and analyzing their antifungal compounds.

2021 ◽  
Vol 22 (2) ◽  
Author(s):  
Qonita Gina Fadhilah ◽  
Iman Santoso ◽  
Yasman YASMAN

Abstract. Fadhilah QG, Santoso I, Yasman. 2021. The antagonistic activity of marine actinomycetes from mangrove ecosystem against phytopathogenic fungi Colletotrichum sp. KA. Biodiversitas 22: 642-649.  Marine actinomycetes from mangrove ecosystems are known to be potential antifungal-producing isolates against phytopathogenic fungi. The aim of this research was to obtain potential marine actinomycetes isolates against the phytopathogenic fungi Colletotrichum sp. KA. Screening of 15 marine actinomycetes isolates using a dual culture method with a plug technique showed that 80% of isolates have antagonistic activity, represented as a percentage of growth inhibition range from 47.96% to 84.94%. Among 12 potential isolates, six isolates (SM4, SM11, SM14, SM15, SM18, and SM20) were evaluated for delayed antagonistic activity with incubation periods of 6, 9, and 12 days using the plug and streak techniques. The results showed that the percentage of growth inhibition of selected isolates inclined to increase along with the incubation period prior to inoculation of Colletotrichum sp. KA. Delayed antagonist assays using the streak technique resulted in higher inhibition results compared to the plug technique. Furthermore, the non-delayed assays of the two selected isolates, SM11 and SM15, also inhibited Colletotrichum sp. KA 57.99% and 59.88%, respectively. The delayed antagonist assay with a shorter incubation period of the two selected isolates also showed an increased percentage of growth inhibition of Colletotrichum sp. KA. According to our research, the delayed antagonistic assay of marine actinomycetes isolates with a 12-day incubation period using a plug technique was representative to evaluate the percentage of growth inhibition.


2021 ◽  
Vol 9 (10) ◽  
pp. 2137
Author(s):  
Yang Zhou ◽  
Shuoxing Yi ◽  
Yi Zang ◽  
Qing Yao ◽  
Honghui Zhu

The application and promotion of biological control agents are limited because of poor efficacy and unstable performance in the field. Screening microorganisms with high antagonistic activity, effective adaptability, and high field-survival should be prospected. Myxobacteria are soil predatory bacteria with wide adaptability, which are considered as good antagonists. Here, we report a myxobacterium strain M34 isolated from subtropical forest soil in South China using the Escherichia coli baiting method. Based on the morphological observation, physiological test, biochemical characteristics, 16S rRNA gene sequence, and genomic data, strain M34 was identified as a novel genus and novel species, representing a new clade of Myxococcaceae, for which the name Citreicoccus inhibens gen. nov. sp. nov. is proposed (type strain M34T = GDMCC 1.2275T = KCTC 82453T). The typical features of M34, including fruiting body formation and extracellular fibrillar interconnection, indicated by microscopic observations, contributed to cell adaption in different environments. Furthermore, the strain showed antifungal activity against phytopathogenic fungi and predatory activity to both Gram-negative and Gram-positive phytopathogenic bacteria. The bioprotective mechanisms are attributed to the presence of pyrrolnitrin and derivative with antifungal activity and the extracellular proteins with lytic activity against pathogenic bacteria. Due to its multiple beneficial traits, strain M34 has the potential to be developed into a versatile biocontrol agent for the management of both fungal and bacterial phytopathogens.


Author(s):  
EUGENE SEBASTIAN J. NIDIRY

Objective: The objective of the study was to evaluate the therapeutic indices (TIs) some antifungal organic compounds and to compare their safety. Methods: TIs of 55 organic compounds were evaluated by dividing their mammalian toxicity values given as median lethal doses ([mg/kg] rat, oral) collected from literature by experimentally determined fungitoxicity values evaluated as median effective concentration (EC50 [mg/L]) for the mycelial growth inhibition of Colletotrichum gloeosporioides on potato dextrose agar medium. Results: Large variations in TIs are observed in different classes of compounds, namely, alcohols, carboxylic acids, phenols, esters, and aldehydes. The relationship between carbon chain length of saturated monohydric alcohols and mammalian toxicity shows that toxicity increases from chain length 1 to 5, declines from 5 to 6, increases from 6 to 7, and steadily declines from 7 to 10. Thus, the relationship is by and large parabolic. The relationship between carbon chain length and molar antifungal activity is also parabolic. In spite of this, large differences are found in TIs making 1-decanol (TI=42.1) a very safe antifungal compound and 1-pentanol (TI=0.17) a hazardous antifungal compound. This is because mammalian toxicity reaches a maximum around carbon chain length of 5, while in the case of antifungal activity, it reaches a maximum around carbon chain length of 10. Conclusions: Among the 55 compounds, whose TIs were evaluated, some compounds with high TIs (>10) which can be considered safe as antifungal compounds are citronellol, geraniol, 1-decanol, 1-octanol, phenyl acetaldehyde, methyl anthranilate, 1-naphthol, 2-naphthol, and propionic acid. Some compounds with low TIs (<0.50) which can be considered hazardous as antifungal compounds are resorcinol, hydroquinone, oxalic acid, and acetyl acetone.


2021 ◽  
Vol 2(26) ◽  
pp. 191-199
Author(s):  
T.M. Sidorova ◽  
◽  
A.M. Asaturova ◽  
V.V. Allakhverdyan ◽  
◽  
...  

The antifungal activity of the Bacillus bacteria is based on their ability to produce metabolites. Therefore, when selecting a strain that produces an effective biofungicide, it is necessary to assess the metabolism of bacteria. The aim of this work is to isolate exo- and endometabolites of the promising B. velezensis BZR 336g and B. velezensis BZR 517 strains and assess their antifungal activity. Studies were carried out in 2020–2021. The object of the study is a liquid culture of the B. velezensis BZR 336g and B. velezensis BZR 517 strains. Methods of liquid extraction, ascending thin layer chromatography (TLC), bioautography with a test-culture of Fusarium oxysporum var. orthoceras and Alternaria sp. fungi were used to analyze metabolites. The ability of the strains to accumulate a complex of active metabolites showing antifungal effect from fungistatic to fungicidal action was revealed. On the bioautogram of exometabolites, we found two most pronounced zones (Rf 0.18 and 0.29) of Fusarium oxysporum var. orthoceras BZR P1 growth inhibition (fungicide). Zones with Rf 0.58 for B. velezensis BZR 336g and Rf 0.70 for B. velezensis BZR 517 correspond to the test fungus growth retardation (fungistatic). Significant suppression of Alternaria sp. BZR P8 growth was also observed in two zones (Rf 0.18 and 0.29). The use of surfactin, iturin A, fengycin (Sigma-Aldrich®) in the TLC analysis made it possible to detect similar lipopeptides in the composition of metabolite complexes produced by the studied bacteria. It should be noted that the studied strains differed both in their ability to produce metabolites of different structure (can be found when analyzing chromatograms under ultraviolet light) and in their effect on phytopathogenic fungi in vitro. This may indicate possible differences in the mechanism of antagonistic activity of bacteria against phytopathogenic fungi. Thus, B. velezensis BZR 336g and B. velezensis BZR 517 produce a significant set of antifungal metabolites and can be used as strains to produce effective biofungicides.


2021 ◽  
Vol 12 (6) ◽  
pp. 7488-7502

Citral is an essential oil with great antimicrobial activity, but its use in the food industry is limited due to its easy decomposition in room conditions. Therefore, this study aimed to microencapsulate citral by the spray drying process and incorporate the powder into pectin films to assess their antifungal activity. For this, solutions of maltodextrin (MD), Arabic gum (AG) sodium alginate (SA) at different concentrations were used to emulsify citral. The emulsion with 10:10:0.1 MD:AG:SA was selected to spray the drying process due to its small droplet size, monomodal size distribution, and low D[3,2], D[4,3], and span index. The dried powder had high solubility (83.4%), and low wettability time (27 s), moisture content (4.05%), and bulk density (0.72 g/cm3), allowing to infer powder stability and showing appropriate handling qualities on a large scale. Thermal analyses reveal that microparticles and pectin films provide thermal protection to citral from 37 to 175 °C. Concerning the antagonistic activity, pectin films added with citral microencapsulated had antifungal activity ranging from 42-68% against Penicillium italicum, Colletotrichum gloeosporioides, and Aspergillus niger under in vitro conditions. Therefore, these films serve as a basis for developing new edible coatings with practical applications in the postharvest management of phytopathogenic fungi.


2021 ◽  
Vol 16 (10) ◽  
pp. 92-101
Author(s):  
Muralidharan Sasidhar ◽  
Selvam Masilamani ◽  
Abirami Baskaran ◽  
Manigundan Kaari ◽  
Radhakrishnan Manikkam

Prolonged use of antifungal drugs has led to the emergence of drug resistant fungal pathogens that pose serious threat to public health and challenge to researchers for discovering novel antifungal agents. Natural products from the members of phylum actinobacteria are the promising source of antibiotics including antifungal agents. Twenty-seven morphologically different actinobacterial cultures were isolated from the forest soils of Sabarimala, Kerala and Lucknow, Uttar Pradesh. Actinobacterial strain LA34 showed promising antifungal activity when screened against Candida albicans and Cryptococcus neoformans, hence selected as potential strain. Antifungal compounds were produced from the strain LA34 using agar surface fermentation and its extraction was done using ethyl acetate and methanol. Results of cultural, microscopic and physiological characteristics as well as cell wall amino acid and sugars analysis revealed that the strain LA34 was nonstreptomyces or rare actinobacterium. Various carbon sources, nitrogen sources and minerals were found to influence antifungal compound production by the strain LA34. The present study concluded that the rare actinobacterial strain LA34 isolated from Lucknow forest soil is a promising source for the isolation of antifungal compounds.


Author(s):  
Jorge A. Cabezas ◽  
José A. Brenes ◽  
Norma Gross ◽  
María L. Arias

In the present study, we synthesized three 1,3-enynes from their corresponding aldehydes. They exhibited antifungal activity, which was evaluated against Trichophyton rubrum, the most common dermatophyte responsible for nail infection. The biological activity of these synthetic enynes was compared to terbinafine and ciclopirox olamine, two common antimycotic drugs used to treat nail infections caused by this pathogen. Two of these compounds showed an inhibitory effect similar to terbinafine and cilopirox olamine, when tested against over eleven different T. rubrum strains, including ATCC 28188 strain and ten different clinical isolates, two already classified as multitreated.


2021 ◽  
Vol 6 (1) ◽  
pp. 59235
Author(s):  
Masrukhin Masrukhin ◽  
Ade Lia Putri ◽  
Tri Ratna Sulistiyani ◽  
Muhammad Ilyas ◽  
Ismu Purwaningsih ◽  
...  

Several bacteria were isolated from straw mushroom (Volvariella volvacea) cultivation medium. There are three potential isolates previously characterized and has growth inhibition effect against V. volvacea. This screening result lead to the further study about the inhibition activity against phytopathogenic fungi. The aim of this research is to investigate the antifungal activity of three bacterial isolates against three phytopathogenic fungi and identification of the bacteria. The method used in this study are antifungal assay using co-culture method and disk difussion assay using the filtrate of each bacteria. The profile of antifungal compound was identified using ethyl acetate extract followed by evaporation and gas chromatography (GC-MS) analysis. Identification of each isolates was performed using 16S rDNA amplification and sequencing. Three phytopathogenic fungi i.e Cercospora lactucae (InaCC F168), Colletotrichum gloeosporides (InaCC F304) and Fusarium oxysporum f.sp. cubense (F817) were co-cultured with bacterial isolates C2.2, C3.8, and D3.3. The C3.8 isolate has highest average inhibition activity either using isolate and filtrate. The result relatively consistent against three phytopathogenic fungi. The metabolite profile of C3.8 isolate showed the Bis(2-ethylhexyl) phthalate as the main compound with 97% similarity. Bis(2-ethylhexyl) phthalate has potential effect as antibacterial and antifungal compound. According to EzBioCloud and GeneBank databases, the C2.2 isolate identified as Bacillus tequilensis, C3.8 as Bacillus siamensis and D3.3 as Bacillus subtilis subsp. Subtilis. This study also shows the potential of Bacillus siamensis C3.8 as biocontrol against phytopathogenic fungi.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Shabnam Javed ◽  
Zaid Mahmood ◽  
Khalid Mohammed Khan ◽  
Satyajit D. Sarker ◽  
Arshad Javaid ◽  
...  

AbstractAntifungal activity of Monothecabuxifolia methanolic extract and its various fractions were assessed against Macrophominaphaseolina, a soil-borne fungal pathogen of more than 500 vegetal species as well as rare and emerging opportunistic human pathogen. Different concentrations of methanolic extract (3.125 to 200 mg mL−1) inhibited fungal biomass by 39–45%. Isolated n-hexane, chloroform and ethyl acetate fractions suppressed fungal biomass by 32–52%, 29–50% and 29–35%, respectively. Triterpenes lupeol and lupeol acetate (1, 2) were isolated from n-hexane while betulin, β-sitosterol, β-amyrin, oleanolic acid (3–6) were isolated from chloroform fraction. Vanillic acid, protocatechuic acid, kaempferol and quercetin (7–10) were isolated from the ethyl acetate fraction and identified using various spectroscopic techniques namely mass spectroscopy and NMR. Antifungal activity of different concentrations (0.0312 to 2 mg mL−1) of the isolated compounds was evaluated and compared with the activity of a broad spectrum fungicide mancozeb. Different concentrations of mencozeb reduced fungal biomass by 83–85%. Among the isolated compounds lupeol acetate (2) was found the highest antifungal against M.phaseolina followed by betulin (3), vanillic acid (7), protocatechuic acid (8), β-amyrin (5) and oleanolic acid (6) resulting in 79–81%, 77–79%, 74–79%, 67–72%, 68–71% and 68–71%, respectively. Rest of the compounds also showed considerable antifungal activity and reduced M.phaseolina biomass by 41–64%.


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