scholarly journals Screening and Identification of Yeasts Antagonistic to Pathogenic Fungi Show a Narrow Optimal pH Range for Antagonistic Activity

2017 ◽  
Vol 66 (1) ◽  
pp. 101-106 ◽  
Author(s):  
Pei-Hua Chen ◽  
Jui-Yu Chou
Keyword(s):  
Interference Competition ◽  
Pathogenic Fungi ◽  
Antagonistic Activity ◽  
Yeast Cells ◽  
Yeast Strains ◽  
Screening And Identification ◽  
Ustilago Esculenta ◽  
Ph Range ◽  
Pichia Kluyveri ◽  
Optimal Ph

Microbes have evolved ways of interference competition to gain advantage over their ecological competitors. The use of secreted antagonistic compounds by yeast cells is one of the prominent examples. Although this killer behavior has been thoroughly studied in laboratory yeast strains, our knowledge of the antagonistic specificity of killer effects in nature remains limited. In this study, yeast strains were collected from various niches and screened for antagonistic activity against one toxin-sensitive strain of Saccharomyces cerevisiae and three pathogenic fungi. We demonstrate that some strains with antagonistic activity against these pathogenic fungi can be found in antagonist culture tests. These yeasts were identified as members of Trichosporon asahii, Candida stellimalicola, Wickerhamomyces anomalus, Ustilago esculenta, Aureobasidium pullulans, and Pichia kluyveri. The results indicated that the antagonistic activity of these killer yeasts has a narrow optimal pH range. Furthermore, we found that the antagonistic activity of some species is strain-dependent.

Biological Control of Peach Fungal Pathogens by Commercial Products and Indigenous Yeasts

2006 ◽  
Vol 69 (10) ◽  
pp. 2465-2470 ◽  
Author(s):  
CRISTINA RESTUCCIA ◽  
FRANCESCO GIUSINO ◽  
FABIO LICCIARDELLO ◽  
CINZIA RANDAZZO ◽  
CINZIA CAGGIA ◽  
...  
Keyword(s):  
Fungal Pathogens ◽  
Mucor Circinelloides ◽  
Antagonistic Activity ◽  
Yeast Cells ◽  
Penicillium Crustosum ◽  
Indigenous Yeasts ◽  
Pichia Kluyveri ◽  
Different Levels ◽  
Potential Use

The potential use of the commercial biocontrol products Serenade (Bacillus subtilis QST-713) and Trichodex (Trichoderma harzianum Rifai strain T39) to inhibit the postharvest pathogenic molds Penicillium crustosum and Mucor circinelloides was investigated. Both products exhibited antagonistic activity in vitro against the pathogens, reducing their growth at different levels. In addition, epiphytic yeasts isolated from peaches were identified as Candida maltosa, Pichia fermentans, and Pichia kluyveri by PCR–restriction fragment length polymorphism of internal transcribed spacer regions and screened for antagonistic activity against the same molds. The efficacy of biocontrol in vitro was dependent on the concentration of the yeast cells. Optimal yeast concentrations were above 107 CFU ml−1. However, C. maltosa and P. fermentans were more effective than P. kluyveri in inhibiting molds. The exclusion of antifungal metabolite production and direct competition for nutrients or space with the pathogens was proposed as the mechanism of biocontrol. Application of biocontrol agents directly on artificially wounded peach fruits significantly reduced the incidence of mold rot during storage at 20°C.

IDENTIFIKASI JENIS JAMUR PATOGEN UNTUK PENGENDALIAN RAYAP TANAH Coptotermes sp.

PERENNIAL ◽  
2010 ◽  
Vol 6 (1) ◽  
pp. 33
Author(s):  
Astuti Arif ◽  
. Syahidah ◽  
Sitti Nuraeni
Keyword(s):  
Key Words ◽  
Pathogenic Fungi ◽  
Wide Distribution ◽  
Subterranean Termite ◽  
The World ◽  
Identification Of Fungi ◽  
Screening And Identification ◽  
Termite Attack ◽  
Penicillium Brevicompactum ◽  
Aspergillus Sp

Fungi have a great diversity and wide distribution at the world. It can be used as the alternative technology for controlling of subterranean termite attack, particularly genus Coptotermes knowned as the wooden destructive organism, by using entomophatogenic fungi. For the purpose of the study, several isolate sources were taken from some locations. The results show that eight numbers of pathogenic fungi was founded by screening and identification of fungi taken from 19 numbers of isolate sources. The pathogenic fungi were Beauveria sp., Penicillium brevicompactum, P. rubrum, Paecilomyces fulvus, Fusarium verticolloides, Pythium sp., and Aspergillus sp. Key words: Jamur entomopatogen, Coptotermes sp.

scholarly journals Antagonistic activity of endophytic bacteria isolated from weed plant against stem end rot pathogen of pitaya in Vietnam

2021 ◽  
Vol 31 (1) ◽  
Author(s):  
The Anh Luu ◽  
Quyet Tien Phi ◽  
Thi Thu Hang Nguyen ◽  
Mai Van Dinh ◽  
Bich Ngoc Pham ◽  
...  
Keyword(s):  
Endophytic Bacteria ◽  
Indole Acetic Acid ◽  
Pathogenic Fungi ◽  
Antagonistic Activity ◽  
Biofilm Production ◽  
Weed Plant ◽  
Seedling Biomass ◽  
Rot Disease ◽  
Positive Results

Abstract Background Fungal stem end rot disease of pitaya caused by Alternaria alternata is one of the most destructive diseases in Binh Thuan province, Vietnam. This study aimed to assess the antagonistic effects of some endophytic bacteria isolated from the weed plant (Echinochloa colonum) against A. alternata. Results A total of 19 endophytic bacteria were isolated and 5 of them presented in vitro antagonistic activity against A. alternata. Of five, strain EC80 significantly inhibited the pathogenic growth with a mean inhibition diameter of 11.88 ± 0.08 mm, while the other four (C79, EC83, EC90, and EC97) showed a weak inhibition. Interestingly, the combination of EC79 and EC80 reduced more biomass of pathogenic fungi than the single one did. EC79 showed positive results for amylase, indole acetic acid (IAA), and biofilm production, whereas EC80 presented positive capabilities for IAA and biofilm production and a negative one for amylase production. In addition, the combined filtrate of EC79 and EC80 presented non-antifungal activity on biocontrol tests in vitro, indicating that bacteria cells played a role in defending against the pathogen. Moreover, both isolates EC79 and EC80 significantly increased seedling biomass than the control. Conclusions The results suggest that those two strains in combination had the potential to be used as a biocontrol agent against A. alternata. More studies should be done in the future to evaluate their efficiency under the field conditions.

scholarly journals Biocontrol potential of Streptomyces sp. CACIS-1.5CA against phytopathogenic fungi causing postharvest fruit diseases

2020 ◽  
Vol 30 (1) ◽  
Author(s):  
Zahaed Evangelista-Martínez ◽  
Erika Anahí Contreras-Leal ◽  
Luis Fernando Corona-Pedraza ◽  
Élida Gastélum-Martínez
Keyword(s):  
Pathogenic Fungi ◽  
Phytopathogenic Fungi ◽  
Antagonistic Activity ◽  
Fruit Rot ◽  
Main Body ◽  
Type I ◽  
Tropical Fruit ◽  
Habanero Pepper ◽  
Antagonistic Microorganisms

Abstract Background Fungi are one of the microorganisms that cause most damage to fruits worldwide, affecting their quality and consumption. Chemical controls with pesticides are used to diminish postharvest losses of fruits. However, biological control with microorganisms or natural compounds is an increasing alternative to protect fruits and vegetables. In this study, the antifungal effect of Streptomyces sp. CACIS-1.5CA on phytopathogenic fungi that cause postharvest tropical fruit rot was investigated. Main body Antagonistic activity was evaluated in vitro by the dual confrontation over fungal isolates obtained from grape, mango, tomato, habanero pepper, papaya, sweet orange, and banana. The results showed that antagonistic activity of the isolate CACIS-1.5CA was similar to the commercial strain Streptomyces lydicus WYEC 108 against the pathogenic fungi Colletotrichum sp., Alternaria sp., Aspergillus sp., Botrytis sp., Rhizoctonia sp., and Rhizopus sp. with percentages ranging from 30 to 63%. The bioactive extract obtained from CACIS-1.5 showed a strong inhibition of fungal spore germination, with percentages ranging from 92 to 100%. Morphological effects as irregular membrane border, deformation, shrinkage, and collapsed conidia were observed on the conidia. Molecularly, the biosynthetic clusters of genes for the polyketide synthase (PKS) type I, PKS type II, and NRPS were detected in the genome of Streptomyces sp. CACIS-1.5CA. Conclusions This study presented a novel Streptomyces strain as a natural alternative to the use of synthetic fungicides or other commercial products having antagonistic microorganisms that were used in the postharvest control of phytopathogenic fungi affecting fruits.

scholarly journals Replicative Aging in Pathogenic Fungi

2020 ◽  
Vol 7 (1) ◽  
pp. 6
Author(s):  
Somanon Bhattacharya ◽  
Tejas Bouklas ◽  
Bettina C. Fries
Keyword(s):  
Cell Division ◽  
Candida Glabrata ◽  
Asymmetric Cell Division ◽  
Pathogenic Fungi ◽  
Yeast Cells ◽  
Candida Auris ◽  
Replicative Aging ◽  
Yeast Saccharomyces Cerevisiae ◽  
Phenotypic Variations ◽  
Systemic Infections

Candida albicans, Candida auris, Candida glabrata, and Cryptococcus neoformans are pathogenic yeasts which can cause systemic infections in immune-compromised as well as immune-competent individuals. These yeasts undergo replicative aging analogous to a process first described in the nonpathogenic yeast Saccharomyces cerevisiae. The hallmark of replicative aging is the asymmetric cell division of mother yeast cells that leads to the production of a phenotypically distinct daughter cell. Several techniques to study aging that have been pioneered in S. cerevisiae have been adapted to study aging in other pathogenic yeasts. The studies indicate that aging is relevant for virulence in pathogenic fungi. As the mother yeast cell progressively ages, every ensuing asymmetric cell division leads to striking phenotypic changes, which results in increased antifungal and antiphagocytic resistance. This review summarizes the various techniques that are used to study replicative aging in pathogenic fungi along with their limitations. Additionally, the review summarizes some key phenotypic variations that have been identified and are associated with changes in virulence or resistance and thus promote persistence of older cells.

scholarly journals Antimicrobial activity of extracellular metabolites from antagonistic bacteria isolated from potato (Solanum phureja) crops

2014 ◽  
Vol 40 (3) ◽  
pp. 212-220 ◽  
Author(s):  
Sinar David Granada García ◽  
Antoni Rueda Lorza ◽  
Carlos Alberto Peláez
Keyword(s):  
Antimicrobial Activity ◽  
Cyclic Peptide ◽  
Biological Activities ◽  
Pathogenic Fungi ◽  
Antagonistic Activity ◽  
Solanum Phureja ◽  
Dual Culture ◽  
Crude Extracts ◽  
Extracellular Metabolites

Microorganisms for biological control are capable of producing active compounds that inhibit the development of phytopathogens, constituting a promising tool toob tain active principles that could replace synthetic pesticides. This study evaluatedtheability of severalpotentialbiocontrol microorganismsto produce active extracellular metabolites. In vitro antagonistic capability of 50 bacterial isolates from rhizospheric soils of "criolla" potato (Solanum phureja) was tested through dual culture in this plant with different plant pathogenic fungi and bacteria. Isolates that showed significantly higher antagonistic activity were fermented in liquid media and crude extracts from the supernatants had their biological activities assessed by optical density techniques. Inhibitory effecton tested pathogens was observed for concentrations between 0.5% and 1% of crude extracts. There was a correlation between the antimicrobial activity of extracts and the use of nutrient-rich media in bacteria fermentation. Using a bioguided method, a peptidic compound, active against Fusarium oxysporum, was obtained from the 7ANT04 strain (Pyrobaculum sp.). Analysis by nuclear magnetic resonance and liquid chromatography coupled to mass detector evidenced an 11-amino acid compound. Bioinformatic software using raw mass data confirmed the presence of a cyclic peptide conformed by 11 mostly non-standard amino acids.

Differentiation of Yeast Cultures in Ruminant Feedingstuffs Using a Rapid DNA Fingerprinting Technique

1994 ◽  
Vol 1994 ◽  
pp. 101-101
Author(s):  
Elizabeth Moore ◽  
Denis R. Headon
Keyword(s):  
Sodium Dodecyl ◽  
Yeast Cells ◽  
Microbial Populations ◽  
Yeast Culture ◽  
Yeast Cultures ◽  
Yeast Strains ◽  
Genetic Sequences ◽  
Polymerase Chain ◽  
Different Strains ◽  
Triton X

Research indicates that certain yeast strains are beneficial in their capacity to stimulate key microbial populations. This stimulation is strain specific with similar yeast strains exerting their effect on totally different microbial populations. Future yeast culture supplements may contain mixtures of different strains designed to suit specific diets. This, therefore, requires the development of a rapid sensitive technique to differentiate among taxonomically similar yeast strains in animal diets. This technique, termed the Randomly Amplified Polymorphic DNA (RAPD) assay, is based upon the use of randomly designed short polynucleotide primers to amplify genetic sequences from the DNA of the desired yeast strain. Our objective involves the development of this technique to distinguish between closely related yeast strains present in feed. The feed sample investigated was a standard cattle ration containing three strains of Saccharomyces cerevisiae (1026, 2045 and 2020) and Candida utilis 3001 at a concentration of 106 CFU/g respectively. Isolation of single colonies of yeast strains present was achieved by feed extraction in dilution buffer followed by plating a series of dilutions on rose-bengal agar. Thirty randomly selected colonies were cultured in YPD (1% yeast extract, 2% peptone, 2% glucose) broth for 24 - 30 hours at 30°C. Genomic DNA was isolated from yeast cells by standard methods based on subjection of the cells to vortex mixing in the presence of glass beads, triton X-100, sodium dodecyl sulphate, phenol and chloroform. Isolated DNA from randomly selected colonies was amplified by Polymerase Chain Reaction (PCR) for 45 cycles of 1 min at 94°C, 1 min at 36°C and 1 min at 72°C using randomly designed 10 bp primers.

scholarly journals Yeasts from Chinese strong flavour Daqu samples: isolation and evaluation of their potential for fortified Daqu production

AMB Express ◽  
2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Shunchang Pu ◽  
Yu Zhang ◽  
Ning Lu ◽  
Cuie Shi ◽  
Shoubao Yan
Keyword(s):  
Volatile Compounds ◽  
Rapd Analysis ◽  
Kluyveromyces Lactis ◽  
Inoculum Size ◽  
Fermentation Efficiency ◽  
Wickerhamomyces Anomalus ◽  
Yeast Strains ◽  
Saccharomyces Kudriavzevii ◽  
Pichia Kluyveri ◽  
The Impact

AbstractIn total, 16 yeast were isolated from Chinese strong flavour Daqu samples and underwent RAPD analysis and identification. Totally, 11 different species were identified among these isolates including Saccharomyces cerevisiae, Hanseniaspora vineae, Pichia kluyveri, Trichosporon asahii, Wickerhamomyces anomalus, Kluyveromyces lactis, Yarrowia lipolytica, Wickerhamomyces mori, Galactomyces geotrichum, Dabaryomyces hansenii, and Saccharomyces kudriavzevii. To understand the impact of these yeast strains on the quality and flavour of Daqu, we then assessed volatile compounds associated with Daqu samples fermented with corresponding strains. These analyses revealed strain YE006 exhibited the most robust ability to produce ethanol via fermentation but yielded relatively low quantities of volatile compounds, whereas strain YE010 exhibited relatively poor fermentation efficiency but produced the greatest quantity of volatile compounds. These two yeast strains were then utilized in a mixed culture to produce fortified Daqu, with the optimal inoculum size being assessed experimentally. These analyses revealed that maximal fermentation, saccharifying, liquefying, and esterifying power as well as high levels of volatile compounds were achieved when using a 2% inoculum composed of YE006/YE010 at a 1:2 (v/v) ratio. When the liquor prepared using this optimized fortified Daqu was compared to unfortified control Daqu, the former was found to exhibit significantly higher levels of flavour compounds and better sensory scores. Overall, our findings may provide a reliable approach to ensuring Daqu quality and improving the consistency and flavour of Chinese strong-flavour liquor through bioaugmentation.

scholarly journals Threonine Overproduction in Yeast Strains Carrying theHOM3-R2 Mutant Allele under the Control of Different Inducible Promoters

1999 ◽  
Vol 65 (1) ◽  
pp. 110-116 ◽  
Author(s):  
María-José Farfán ◽  
Luis Aparicio ◽  
Isabel L. Calderón
Keyword(s):  
Mutant Allele ◽  
Metabolic Flux ◽  
Dry Weight ◽  
Yeast Cells ◽  
Aspartate Kinase ◽  
Inducible Promoters ◽  
Yeast Strains ◽  
Threonine Production ◽  
Amino Acid Contents ◽  
Serine Deaminase

ABSTRACT The HOM3 gene of Saccharomyces cerevisiaecodes for aspartate kinase, which plays a crucial role in the regulation of the metabolic flux that leads to threonine biosynthesis. With the aim of obtaining yeast strains able to overproduce threonine in a controlled way, we have placed the HOM3-R2 mutant allele, which causes expression of a feedback-insensitive enzyme, under the control of four distinctive regulatable yeast promoters, namely, P GAL1 , P CHA1 , P CYC1-HSE2 , and P GPH1 . The amino acid contents of strains bearing the different constructs were analyzed both under repression and induction conditions. Although some differences in overall threonine production were found, a maximum of around 400 nmol/mg (dry weight) was observed. Other factors, such as excretion to the medium and activity of the catabolic threonine/serine deaminase, also affect threonine accumulation. Thus, improvement of threonine productivity by yeast cells would probably require manipulation of these and other factors.

scholarly journals Evaluation of in vitro antagonistic activity of fungi from peatlands against Ganoderma species under acidic condition

2020 ◽  
Vol 21 (7) ◽  
Author(s):  
SUPRIYANTO ◽  
PURWANTO ◽  
S.H. POROMARTO ◽  
SUPYANI
Keyword(s):  
Biological Control ◽  
Antagonistic Activity ◽  
Biological Control Agents ◽  
Antagonistic Fungi ◽  
High Incidence ◽  
Acidic Conditions ◽  
Mineral Soils ◽  
Ph Range ◽  
Biological Methods

Abstract. Supriyanto, Purwanto, Poromarto SH, Supyani. 2020. Evaluation of in vitro antagonistic activity of fungi from peatlands against Ganoderma species under acidic conditions. Biodiversitas 21: 2935-2945. The use of peatlands is a significant contributor to the world’s palm oil production. A serious problem of oil palm plantations in peatlands is the high incidence of basal stem rot (BSR) disease caused by Ganoderma, which has a higher attack rate than on mineral soils. There is no effective way to control Ganoderma in peatlands. At present, the effort for the same focuses on environment-friendly biological methods; however, this is constrained by the unavailability of appropriate biological agents for peatlands. The development of biological control agents for peatlands is hampered by limited data on biological control of Ganoderma in peatlands. This research was conducted to evaluate the in vitro antagonistic activity of fungi isolated from a peatland in acidic pH conditions. Twenty-seven Ganoderma-antagonistic fungi from peatland were evaluated for their activity and their ability to antagonism in vitro within a pH range of 2-7. The results show that most antagonistic fungi from peatland, based on biomass weight, the sporulation ability, and germination of conidium, were able to grow optimally at pH 3.0-4.0, indicating that most of the Ganoderma-antagonistic fungi from peatland can be used as biological control agents for BSR on oil palms in peatlands.

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