scholarly journals Correlation between water activity (aw) and microbial epiphytic communities associated with grapes berries

OENO One ◽  
2020 ◽  
Vol 54 (1) ◽  
pp. 49-61
Author(s):  
Guilherme Eduardo Martins ◽  
Cosimo Casini ◽  
Jean-Pierre Da Costa ◽  
Laurence Geny ◽  
Aline Lonvaud ◽  
...  

Grape berries host a complex microbial community that plays a predominant role in grape quality prior to harvest and in the winemaking process. Like other carpospheric habitats, the epiphytic microbial community of grape berries is influenced by several factors. Climate plays an essential role in grape composition and quality, and its impact on berry microbiota was recently demonstrated. However, there is still a lack of information about how environmental conditions influence the system in grape berries.In this study, the microbial communities of grape berries from two wine appellations characterized by specific climatological conditions were analyzed. The results revealed that the size of cultivable communities (bacteria, yeast and filamentous fungi) and the diversity and richness of the microbial community profiles were higher in vineyards found to have lower temperatures. The metabolic activity (Community-Level Physiological Profiles) of the epiphytic microbial community was lower in warm climates. Water activity (aw) had a positive effect on the cultivable population, on metabolic activity, and on microbial diversity.The results showed that the microclimate affects the microbial population associated with grape berries through the aw of grape skins.

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
María-Eugenia DeCastro ◽  
Michael P. Doane ◽  
Elizabeth Ann Dinsdale ◽  
Esther Rodríguez-Belmonte ◽  
María-Isabel González-Siso

AbstractIn the present study we investigate the microbial community inhabiting As Burgas geothermal spring, located in Ourense (Galicia, Spain). The approximately 23 Gbp of Illumina sequences generated for each replicate revealed a complex microbial community dominated by Bacteria in which Proteobacteria and Aquificae were the two prevalent phyla. An association between the two most prevalent genera, Thermus and Hydrogenobacter, was suggested by the relationship of their metabolism. The high relative abundance of sequences involved in the Calvin–Benson cycle and the reductive TCA cycle unveils the dominance of an autotrophic population. Important pathways from the nitrogen and sulfur cycle are potentially taking place in As Burgas hot spring. In the assembled reads, two complete ORFs matching GH2 beta-galactosidases were found. To assess their functional characterization, the two ORFs were cloned and overexpressed in E. coli. The pTsbg enzyme had activity towards o-Nitrophenyl-β-d-galactopyranoside (ONPG) and p-Nitrophenyl-β-d-fucopyranoside, with high thermal stability and showing maximal activity at 85 °C and pH 6, nevertheless the enzyme failed to hydrolyze lactose. The other enzyme, Tsbg, was unable to hydrolyze even ONPG or lactose. This finding highlights the challenge of finding novel active enzymes based only on their sequence.


2005 ◽  
Vol 68 (1) ◽  
pp. 40-48 ◽  
Author(s):  
ANABELLE MATOS ◽  
JAY L. GARLAND

Potential biological control inoculants, Pseudomonas fluorescens 2-79 and microbial communities derived from market sprouts or laboratory-grown alfalfa sprouts, were introduced into alfalfa seeds with and without a Salmonella inoculum. We examined their ability to inhibit the growth of this foodborne pathogen and assess the relative effects of the inoculants on the alfalfa microbial community structure and function. Alfalfa seeds contaminated with a Salmonella cocktail were soaked for 2 h in bacterial suspensions from each inoculant tested. Inoculated alfalfa seeds were grown for 7 days and sampled during days 1, 3, and 7. At each sampling, alfalfa sprouts were sonicated for 7 min to recover microflora from the surface, and the resulting suspensions were diluted and plated on selective and nonselective media. Total bacterial counts were obtained using acridine orange staining, and the percentage culturability was calculated. Phenotypic potential of sprout-associated microbial communities inoculated with biocontrol treatments was assessed using community-level physiological profiles based on patterns of use of 95 separate carbon sources in Biolog plates. Community-level physiological profiles were also determined using oxygen-sensitive fluorophore in BD microtiter plates to examine functional patterns in these communities. No significant differences in total and mesophilic aerobe microbial cell density or microbial richness resulting from the introduction of inoculants on alfalfa seeds with and without Salmonella were observed. P. fluorescens 2-79 exhibited the greatest reduction in the growth of Salmonella early during alfalfa growth (4.22 log at day 1), while the market sprout inoculum had the reverse effect, resulting in a maximum log reduction (5.48) of Salmonella on day 7. Community-level physiological profiles analyses revealed that market sprout communities peaked higher and faster compared with the other inoculants tested. These results suggest that different modes of actions of single versus microbial consortia biocontrol treatments may be involved.


2017 ◽  
Vol 52 (10) ◽  
pp. 946-950
Author(s):  
Douglas André Würz ◽  
José Luiz Marcon Filho ◽  
Alberto Fontanella Brighenti ◽  
Ricardo Allebrandt ◽  
Betina Pereira de Bem ◽  
...  

Abstract: The objective of this work was to evaluate the chemical composition of 'Cabernet Franc' grape subjected to different levels of shoot topping. The experiment was conducted in the 2008 and 2009 vintages, and the levels of shoot topping consisted of: control, without topping; and reductions of 15, 30, and 45% in total leaf area. The effect of shoot topping intensity on the chemical composition of the 'Cabernet Franc' grape berries was observed. A reduction of 26% in the vegetative canopy through a moderate shoot topping increased the total polyphenol index and the anthocyanin content. Shoot topping is a practice that must be carried out with caution, since severe shoot topping, i.e., a reduction greater than 26% of the leaf area, may negatively impact grape quality by reducing the content of soluble solids and decreasing the total polyphenol index and the content of anthocyanins of 'Cabernet Franc' grape berries.


mBio ◽  
2021 ◽  
Vol 12 (4) ◽  
Author(s):  
Yiqiao Bao ◽  
Andrew A. Verdegaal ◽  
Brent W. Anderson ◽  
Natasha A. Barry ◽  
Jing He ◽  
...  

The human intestine harbors a highly complex microbial community; interpersonal variation in this community can impact pathogen susceptibility, metabolism, and other aspects of health. Here, we identified and characterized a commensal-targeting antibacterial protein encoded in the gut microbiome.


2021 ◽  
Vol 12 ◽  
Author(s):  
Linnan Wu ◽  
Zhiqiang Li ◽  
Fengyun Zhao ◽  
Benzhou Zhao ◽  
Fesobi Olumide Phillip ◽  
...  

Fertilizer practices can significantly impact the fruit quality and microbial diversity of the orchards. The fungi on the surface of fruits are essential for fruit storability and safety. However, it is not clear whether fertilization affects the fungal diversity and community structure on the surface of grape berries. Here, grape quality and the fungal diversity on the surface of grapes harvested from three fertilizer treatments were analyzed shortly after grape picking (T0) and following 8 days of storage (T1). The study involved three treatments: (1) common chemical fertilizer for 2 years (CH); (2) increased organic fertilizer and reduced chemical fertilizer for 1 year (A.O); and (3) increased organic fertilizer and reduced chemical fertilizer for 2 years (B.O). The application of increased organic fertilizer and reduced chemical fertilizer increased the soluble solids content (SSC) of the grape berries and decreased the pH of the grape juice. A total of 827,947 high-quality fungal sequences were recovered and assigned to 527 operational taxonomic units. Members of the Ascomycota phylum were dominant in all samples and accounted for 94.41% of the total number of detected sequences, followed by the Basidiomycota (5.05%), and unidentified fungi (0.54%). Alpha and beta diversity analyses revealed significantly different fungal populations in the three fertilizer treatments over the two time periods. The fungal diversity and richness on the grape berry surface in the B.O and A.O treatments were higher than those in the CH treatment. Among the detected fungi, the B.O treatments were mainly Pichia, Aureobasidium, and Candida genera, while the CH treatments were Botrytis, Aspergillus, and Penicillium. Moreover, significant differences were revealed between the two assessment times (T0 and T1). The samples from the T0 timepoint had higher fungal richness and diversity than the samples from T1 timepoint. Increasing organic fertilizer usage in grape management could improve grape quality and went on to increase the fungal diversity, as well as the relative abundance (RA) of beneficial fungi on grape berry surfaces. The correlation analysis suggested that the pH of the grape juice was significantly negatively correlated with fungal diversity parameters.


2019 ◽  
Vol 28 (15) ◽  
pp. 3496-3507 ◽  
Author(s):  
John K. Pearman ◽  
Eva Aylagas ◽  
Christian R. Voolstra ◽  
Holger Anlauf ◽  
Rodrigo Villalobos ◽  
...  

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