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Journal of Economic Entomology Apr 2023Carpophilus davidsoni (Dobson) is an important pest of Australian stone fruit. Current management practices for this beetle include the use of a trap that contains an...
Carpophilus davidsoni (Dobson) is an important pest of Australian stone fruit. Current management practices for this beetle include the use of a trap that contains an attractant lure comprised of aggregation pheromones and a 'co-attractant' mixture of volatiles from fruit juice fermented using Baker's yeast, Saccharomyces cerevisiae (Hansen). We explored whether volatiles from yeasts Pichia kluyveri (Bedford) and Hanseniaspora guilliermondii (Pijper), which are closely associated with C. davidsoni in nature, might improve the effectiveness of the co-attractant. Field trials using live yeast cultures revealed that P. kluyveri trapped higher numbers of C. davidsoni compared to H. guilliermondii, and comparative GC-MS of volatile emissions of the two yeasts led to the selection of isoamyl acetate and 2-phenylethyl acetate for further investigation. In subsequent field trials, trap catches of C. davidsoni were significantly increased when 2-phenylethyl acetate was added to the co-attractant, compared to when isoamyl acetate was added, or both isoamyl acetate and 2-phenylethyl acetate. We also tested different concentrations of ethyl acetate in the co-attractant (the only ester in the original lure) and found contrasting results in cage bioassays and field trails. Our study demonstrates how exploring volatile emissions from microbes that are ecologically associated with insect pests can result in more potent lures for use in integrated pest management strategies. Results from laboratory bioassays screening volatile compounds should be treated with caution when making inferences regarding attraction under field conditions.
Topics: Animals; Coleoptera; Fruit; Australia; Yeasts; Pheromones
PubMed: 36881679
DOI: 10.1093/jee/toad027 -
Journal of Microbiology (Seoul, Korea) Jan 2019White colony-forming yeasts (WCFYs) often appear in fermented foods, depending on the storage method. Despite the ongoing research on fermented foods, the community and...
White colony-forming yeasts (WCFYs) often appear in fermented foods, depending on the storage method. Despite the ongoing research on fermented foods, the community and genome features of WCFYs have not been well studied. In this study, the community structures of WCFYs on fermented vegetables (kimchi) prepared with various raw materials were investigated using deep sequencing. Only eight operational taxonomic units (OTUs) were detected, indicating that the community structure of WCFYs on kimchi is very simple. The five most abundant OTUs represented Pichia kluyveri, Yarrowia lipolytica, Candida sake, Hanseniaspora uvarum, and Kazachstania servazzii. Using a culture-dependent method, 41 strains representing the five major OTUs were isolated from the surface of the food samples. Whole genomes of the five major yeast strains were sequenced and annotated. The total genome length for the strains ranged from 8.97 Mbp to 21.32 Mbp. This is the first study to report genome sequences of the two yeasts Pichia kluyveri and Candida sake. Genome analysis indicated that each yeast strain had core metabolic pathways such as oxidative phosphorylation; purine metabolism; glycolysis/gluconeogenesis; aminoacyl-tRNA biosynthesis; citrate cycle; but strain specific pathways were also found. In addition, no toxin or antimicrobial resistance genes were identified. Our study provides genome information for five WCFY strains that may highlight their potential beneficial or harmful metabolic effects in fermented vegetables.
Topics: Fermentation; Fermented Foods; Genome, Fungal; Genomics; Phylogeny; Vegetables; Yeasts
PubMed: 30392155
DOI: 10.1007/s12275-019-8487-y -
Journal of Chemical Ecology Sep 2017Yeast-insect interactions have been well characterized in drosophilid flies, but not in tephritid fruit flies, which include many highly polyphagous pest species that...
Yeast-insect interactions have been well characterized in drosophilid flies, but not in tephritid fruit flies, which include many highly polyphagous pest species that attack ripening fruits. Using the Queensland fruit fly (Bactrocera tryoni) as our model tephritid species, we identified yeast species present in the gut of wild-collected larvae and found two genera, Hanseniaspora and Pichia, were the dominant isolates. In behavioural trials using adult female B. tryoni, a fruit-agar substrate inoculated with Pichia kluyveri resulted in odour emissions that increased the attraction of flies, whereas inoculation with Hanseniaspora uvarum, produced odours that strongly deterred flies, and both yeasts led to decreased oviposition. Larval development trials showed that the fruit-agar substrate inoculated with the 'deterrent odour' yeast species, H. uvarum, resulted in significantly faster larval development and a greater number of adult flies, compared to a substrate inoculated with the 'attractive odour' yeast species, P. kluyveri, and a yeast free control substrate. GC-MS analysis of volatiles emitted by H. uvarum and P. kluyveri inoculated substrates revealed significant quantitative differences in ethyl-, isoamyl-, isobutyl-, and phenethyl- acetates, which may be responsible for the yeast-specific olfactory responses of adult flies. We discuss how our seemingly counterintuitive finding that female B. tryoni flies avoid a beneficial yeast fits well with our understanding of female choice of oviposition sites, and how the contrasting behavioural effects of H. uvarum and P. kluyveri raises interesting questions regarding the role of yeast-specific volatiles as cues to insect vectors. A better understanding of yeast-tephritid interactions could assist in the future management of tephritid fruit fly pests through the formulation of new "attract and kill" lures, and the development of probiotics for mass rearing of insects in sterile insect control programs.
Topics: Animals; Female; Insect Control; Larva; Odorants; Oviposition; Pest Control, Biological; Pichia; Plant Diseases; Prunus domestica; Prunus persica; Psidium; Reproduction; Saccharomycetales; Smell; Tephritidae
PubMed: 28836040
DOI: 10.1007/s10886-017-0877-1 -
Microorganisms Jan 2022Sourdough is one of the oldest starters traditionally used for making baked goods, offering several advantages to the sensory, rheology, and shelf life of final...
Sourdough is one of the oldest starters traditionally used for making baked goods, offering several advantages to the sensory, rheology, and shelf life of final products. The present study investigated, for the first time, the microbiota of spontaneously fermented Maiorca dough samples collected from bakeries located in Sicily (Italy). Four sourdough samples (M1, M2, M3, and M4), were produced using Host. var. Koern (Maiorca grain) were subjected to LAB and yeasts isolation and identification at the species level. The in-depth characterization of the lactobacilli population revealed that and unquestionably dominated the Maiorca sourdough ecosystem. Concerning the yeasts community, high species diversity was found. and were the most frequently isolated species. In addition, and were also detected. Investigations on both pro-technological and functional traits of the isolated strains could lead to the selection of starters for the production of baked goods.
PubMed: 35208738
DOI: 10.3390/microorganisms10020283 -
BMC Microbiology Jan 2017While recent advances in next generation sequencing technologies have enabled researchers to readily identify countless microbial species in soil, rhizosphere, and...
BACKGROUND
While recent advances in next generation sequencing technologies have enabled researchers to readily identify countless microbial species in soil, rhizosphere, and phyllosphere microbiomes, the biological functions of the majority of these species are unknown. Functional studies are therefore urgently needed in order to characterize the plethora of microorganisms that are being identified and to point out species that may be used for biotechnology or plant protection. Here, we used a dual culture assay and growth analyses to characterise yeasts (40 different isolates) and their antagonistic effect on 16 filamentous fungi; comprising plant pathogens, antagonists, and saprophytes.
RESULTS
Overall, this competition screen of 640 pairwise combinations revealed a broad range of outcomes, ranging from small stimulatory effects of some yeasts up to a growth inhibition of more than 80% by individual species. On average, yeasts isolated from soil suppressed filamentous fungi more strongly than phyllosphere yeasts and the antagonistic activity was a species-/isolate-specific property and not dependent on the filamentous fungus a yeast was interacting with. The isolates with the strongest antagonistic activity were Metschnikowia pulcherrima, Hanseniaspora sp., Cyberlindnera sargentensis, Aureobasidium pullulans, Candida subhashii, and Pichia kluyveri. Among these, the soil yeasts (C. sargentensis, A. pullulans, C. subhashii) assimilated and/or oxidized more di-, tri- and tetrasaccharides and organic acids than yeasts from the phyllosphere. Only the two yeasts C. subhashii and M. pulcherrima were able to grow with N-acetyl-glucosamine as carbon source.
CONCLUSIONS
The competition assays and physiological experiments described here identified known antagonists that have been implicated in the biological control of plant pathogenic fungi in the past, but also little characterised species such as C. subhashii. Overall, soil yeasts were more antagonistic and metabolically versatile than yeasts from the phyllosphere. Noteworthy was the strong antagonistic activity of the soil yeast C. subhashii, which had so far only been described from a clinical sample and not been studied with respect to biocontrol. Based on binary competition assays and growth analyses (e.g., on different carbon sources, growth in root exudates), C. subhashii was identified as a competitive and antagonistic soil yeast with potential as a novel biocontrol agent against plant pathogenic fungi.
Topics: Antibiosis; Biological Control Agents; Candida; DNA, Fungal; Fungi; Genome, Fungal; Genome, Mitochondrial; High-Throughput Nucleotide Sequencing; Malus; Plant Roots; Plants; Rhizosphere; Soil; Soil Microbiology
PubMed: 28056814
DOI: 10.1186/s12866-016-0908-z -
Folia Microbiologica Mar 2015Many different yeast species have been isolated from grapes and musts worldwide. The diversity and frequency of yeasts depend on a number of factors such as the grape...
Many different yeast species have been isolated from grapes and musts worldwide. The diversity and frequency of yeasts depend on a number of factors such as the grape variety, the physical damage of the grapes, the weather conditions and the chemical composition of must. A total of 366 isolates were associated with the three grape cultivars: Blue Frankish, Green Veltliner and Sauvignon blanc over four consecutive years. Yeast cultures were isolated from the grapes and from the fermenting musts after the first and seventh days. The ascomycetous yeasts of the genera Aureobasidium, Candida, Hanseniaspora, Metschnikowia, Pichia, Saccharomyces and Saccharomycopsis together with basidiomycetous yeasts of the genera Cryptococcus, Dioszegia, Filobasidium, Rhodotorula and Sporidiobolus were associated with the three grape varieties. Hanseniaspora uvarum, Metschnikowia pulcherrima, Pichia kluyveri, Pichia kudriavzevii and Sporidiobolus pararoseus were found on the berries in significant amounts. P. kluyveri and P. kudriavzevii were more associated with the damaged grapes, whereas Sp. pararoseus with intact ones. H. uvarum and M. pulcherrima were present on both types of grapes almost equally. The yeast composition and quantitative representation of yeast species varied over the grape varieties and the years examined. Although the basidiomycetous species formed a significant proportion of the yeast population in some individual grape variety/year combinations, the ascomycetous species were dominant.
Topics: Biodiversity; DNA, Fungal; DNA, Ribosomal; Fungi; Genes, rRNA; Phylogeny; RNA, Fungal; RNA, Ribosomal; Sequence Analysis, DNA; Slovakia; Vitis; Wine
PubMed: 25253264
DOI: 10.1007/s12223-014-0347-x -
Antonie Van Leeuwenhoek Apr 2015A novel killer protein (Pkkp) secreted by a Pichia kluyveri strain isolated from an Algerian soil was active against food and beverage spoilage yeasts of the genera...
A novel killer protein from Pichia kluyveri isolated from an Algerian soil: purification and characterization of its in vitro activity against food and beverage spoilage yeasts.
A novel killer protein (Pkkp) secreted by a Pichia kluyveri strain isolated from an Algerian soil was active against food and beverage spoilage yeasts of the genera Dekkera, Kluyveromyces, Pichia, Saccharomyces, Torulaspora, Wickerhamomyces and Zygosaccharomyces. After purification by gel filtration chromatography Pkkp revealed an apparent molecular mass of 54 kDa with SDS-PAGE. Minimum inhibitory concentrations (MICs) of purified Pkkp exhibited a high in vitro activity against Dekkera bruxellensis (MICs from 64,000- to 256,000-fold lower than that exhibited by potassium metabisulphite) and Saccharomyces cerevisiae (MICs from 32,000- to 64,000- fold lower than potassium sorbate). No in vitro synergistic interactions (calculated by FIC index - Σ FIC) were observed when Pkkp was used in combination with potassium metabisulphite, potassium sorbate, or ethanol. Pkkp exhibited a dose-response effect against D. bruxellensis and S. cerevisiae in a low-alcoholic drink and fruit juice, respectively. The results of the present study suggest that Pkkp could be proposed as a novel food-grade compound useful for the control of food and beverage spoilage yeasts.
Topics: Algeria; Drug Synergism; Food Microbiology; Fungal Proteins; Microbial Sensitivity Tests; Mycotoxins; Pichia; Soil Microbiology; Yeasts
PubMed: 25618417
DOI: 10.1007/s10482-015-0388-4 -
Food Research International (Ottawa,... Jul 2022The aim of the present study was to characterize the bacterial and fungal communities naturally occurring in Queijo da Beira Baixa PDO cheese samples produced in Castelo...
The aim of the present study was to characterize the bacterial and fungal communities naturally occurring in Queijo da Beira Baixa PDO cheese samples produced in Castelo Branco district (Beira Baixa Region, Portugal) through viable counts and metataxonomic analyses. Physico-chemical and morpho-textural analyses were also carried out, together with the analysis of volatile organic compounds (VOCs). In the analyzed samples, pH values ranged between 4.72 ± 0.15 and 5.85 ± 0.02, with values of lactic acid content comprised between 0.64 ± 0.00 and 1.95 ± 0.16 g 100 g. Specific volume of cheese ranged from 1.09 ± 0.08 to 1.32 ± 0.02 g mL. Texture profile analysis showed hardness ranging between 38.3 ± 9.6 N and 68.55 ± 7.5 N. As for lactic acid bacteria, presumptive lactococci, thermophilic cocci, and lactobacilli counts up to 9 Log cfu g. Coagulase-negative cocci showed counts up to 7 Log cfu g. Enterococci counts were up to 6 Log cfu g. Finally, counts of eumycetes showed values up to 4 Log cfu g. The results of metataxonomic analysis of bacteria showed the dominance of Lactococcus lactis in all the samples. Moreover, other taxa were detected, including Lactiplantibacillus plantarum, Loigolactobacillus coryniformis, Lactococcus piscium, Streptococcus thermophilus, and Lacticaseibacillus zeae. Mycobiota was characterized by the presence of Candida sake, Ustilago, Cladosporium variabile, Starmerella, Debaryomyces hansenii, and Pichia kluyveri. In the analyzed Queijo da Beira Baixa PDO cheese samples, carboxylic acids represented the most detected VOCs, followed by esters, carbonyl compounds, and alcohols.
Topics: Cheese; Food Microbiology; Lactococcus lactis; Portugal; Streptococcus thermophilus
PubMed: 35761707
DOI: 10.1016/j.foodres.2022.111481 -
Brazilian Journal of Biology = Revista... Nov 2018Although invasive infections and mortality caused by Candida species are increasing among compromised patients, resistance to common antifungal agents is also an...
Although invasive infections and mortality caused by Candida species are increasing among compromised patients, resistance to common antifungal agents is also an increasing problem. We analyzed 60 yeasts isolated from patients with invasive candidiasis using a PCR/RFLP strategy based on the internal transcribed spacer (ITS2) region to identify different Candida pathogenic species. PCR analysis was performed from genomic DNA with a primer pair of the ITS2-5.8S rDNA region. PCR-positive samples were characterized by RFLP. Restriction resulted in 23 isolates identified as C. albicans using AlwI, 24 isolates as C. parapsilosis using RsaI, and 13 as C. tropicalis using XmaI. Then, a group of all isolates were evaluated for their susceptibility to a panel of previously described killer yeasts, resulting in 75% being susceptible to at least one killer yeast while the remaining were not inhibited by any strain. C. albicans was the most susceptible group while C. tropicalis had the fewest inhibitions. No species-specific pattern of inhibition was obtained with this panel of killer yeasts. Metschnikowia pulcherrima, Pichia kluyveri and Wickerhamomyces anomalus were the strains that inhibited the most isolates of Candida spp.
Topics: Adult; Antifungal Agents; Candida; Candidiasis, Invasive; Humans; Microbial Sensitivity Tests; Polymerase Chain Reaction; Polymorphism, Restriction Fragment Length
PubMed: 29412252
DOI: 10.1590/1519-6984.175635 -
Pathogens (Basel, Switzerland) Oct 2023Yeasts associated with lepidopteran pests have been shown to play a role in their survival, development, and oviposition preference. It has been demonstrated that...
Yeasts associated with lepidopteran pests have been shown to play a role in their survival, development, and oviposition preference. It has been demonstrated that combining these yeasts with existing biological control agents can enhance their efficacy. The tortricid is a phytosanitary pest in the South African citrus industry, with the baculovirus Cryptophlebia leucotreta granulovirus (CrleGV) being one of the components that can control this pest. Several yeast species were shown to be associated with larvae, which affected their behaviour and development. A series of detached fruit bioassays were performed to determine whether the combination of yeast with CrleGV enhances its efficacy. These assays included determining the optimal yeast/virus ratio, testing all isolated yeast species in combination with CrleGV, and further improving yeast/virus formulation by adding an adjuvant. The optimal yeast concentration to use alongside CrleGV was determined to be 10 cells·mL. , , , and in combination with CrleGV reduced larval survival compared to CrleGV alone. The addition of molasses and BREAK-THRU S 240 to . and . in combination with CrleGV did not notably improve their effectiveness; however, there was an observed decrease in larval survival. In future studies, field trials will be conducted with combinations of CrleGV and or . to investigate whether these laboratory findings can be replicated in orchard conditions.
PubMed: 37887753
DOI: 10.3390/pathogens12101237