scholarly journals Comparison of efficacy and modes of action of two high-potential biocontrol Bacillus strains and commercial biocontrol products against Botrytis cinerea in table grapes

OENO One ◽  
2021 ◽  
Vol 55 (3) ◽  
pp. 228-243
Author(s):  
Héctor Calvo ◽  
Jean Roudet ◽  
Ana Pilar Gracia ◽  
María Eugenia Venturini ◽  
Marc Fermaud
Keyword(s):  
Botrytis Cinerea ◽  
Culture Medium ◽  
Biological Control Agent ◽  
Living Cells ◽  
High Potential ◽  
Main Mode ◽  
Culture Form ◽  
Table Grapes ◽  
New Findings ◽  
Disease Reduction

In table grapes (cv. Thomson Seedless), the antifungal activity against Botrytis cinerea was further analysed and compared between two high potential bacterial biological control agent (BCA) strains, Bacillus velezensis BUZ-14 and B. ginsengihumi S38. Two commercial biocontrol products (BPs), served as standards of comparison, Amylo-X® and Serenade Max®, also based on Bacillus BCA strains. The main mode of action quantified for all the strains was antibiosis due to hydrosoluble and volatile metabolites and their combinations. The BUZ-14 strain was the most active BCA strain, demonstrating significant disease reduction exceeding 60 % when used in the culture form grown in 863 medium, including living cells (LCs) and cell-free supernatant (CFS). Both BPs exhibited significantly reduced efficacy of their CFS fraction (< 10 %) compared with that of the two BCA strains, confirming their high antibiosis potential. The novel methodology allowed us to demonstrate the significant effect of the BCA culture medium on volatilome (VOC) antagonist efficacy. The S38 strain achieved the highest disease reduction (90 %) owing to the greatest production of VOCs in the richest MOLP (Medium Optimum Lipopetide Production) culture medium, whereas grape juice was the least favourable medium for VOC efficacy for both bacterial strains (BUZ14 and S38). The overall poor activity of living Bacillus cells in all the BCA and BPs tested is discussed based on the low capacity of the BCA strains to grow in the berry. Then, the presence of living cells is also discussed with the possibility that these cells are not required in field applications of such BCA strains in this genus. Moreover, different environmental suboptimal conditions, including temperature (22 and 27 °C) and relative humidity (RH) (100 and 85–95 %), were tested, and BUZ-14 exhibited the highest Botrytis reduction at both temperatures and RH values. However, no significant differences were observed between temperatures or RH values for the same BCA. Further studies in vineyard conditions and applications, such as biofumigation or active packaging, will be performed to confirm the new findings reported in this investigation.

scholarly journals Genomic Analysis and Secondary Metabolites Production of the Endophytic Bacillus velezensis Bvel1: A Biocontrol Agent against Botrytis cinerea Causing Bunch Rot in Post-Harvest Table Grapes

Plants ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 1716
Author(s):  
Kallimachos Nifakos ◽  
Polina C. Tsalgatidou ◽  
Eirini-Evangelia Thomloudi ◽  
Aggeliki Skagia ◽  
Dimitrios Kotopoulis ◽  
...  
Keyword(s):  
Cell Culture ◽  
Botrytis Cinerea ◽  
Biological Control Agent ◽  
Gene Clusters ◽  
Bacillus Velezensis ◽  
Post Harvest ◽  
Grape Berries ◽  
Table Grapes ◽  
Bunch Rot

Botrytis bunch rot caused by Botrytis cinerea is one of the most economically significant post-harvest diseases of grapes. In the present study, we showed that the bacterial strain Bvel1 is phylogenetically affiliated to Bacillus velezensis species. The strain Bvel1 and its secreted metabolites exerted an antifungal activity, under in vitro conditions, against B. cinerea. UHPLC–HRMS chemical analysis revealed that iturin A2, surfactin-C13 and -C15, oxydifficidin, bacillibactin, L-dihydroanticapsin, and azelaic acid were among the metabolites secreted by Bvel1. Treatment of wounded grape berries with Bacillus sp. Bvel1 cell culture was effective for controlling grey mold ingress and expansion in vivo. The effectiveness of this biological control agent was a function of the cell culture concentration of the antagonist applied, while preventive treatment proved to be more effective compared to curative. The strain Bvel1 exhibited an adequate colonization efficiency in wounded grapes. The whole-genome phylogeny, combined with ANI and dDDH analyses, provided compelling evidence that the strain Bvel1 should be taxonomically classified as Bacillus velezensis. Genome mining approaches showed that the strain Bvel1 harbors 13 antimicrobial biosynthetic gene clusters, including iturin A, fengycin, surfactin, bacilysin, difficidin, bacillaene, and bacillibactin. The results provide new insights into the understanding of the endophytic Bacillus velezensis Bvel1 biocontrol mechanism against post-harvest fungal pathogens, including bunch rot disease in grape berries.

scholarly journals Ethanol for postharvest decay control of table grapes: application and mode of action

2005 ◽  
Author(s):  
Amnon Lichter ◽  
Joseph L. Smilanick ◽  
Dennis A. Margosan ◽  
Susan Lurie
Keyword(s):  
Botrytis Cinerea ◽  
Mode Of Action ◽  
Biological Control Agent ◽  
Free Water ◽  
Lethal Effect ◽  
Control Agent ◽  
Modified Atmosphere ◽  
Effective Measure ◽  
Table Grapes ◽  
Major Mode

Original objectives: Dipping of table grapes in ethanol was determined to be an effective measure to control postharvest gray mold infection caused by Botrytis cinerea. Our objectives were to study the effects of ethanol on B.cinerea and table grapes and to conduct research that will facilitate the implementation of this treatment. Background: Botrytis cinerea is known as the major pathogen of table grapes in cold storage. To date, the only commercial technology to control it relied on sulfur dioxide (SO₂) implemented by either fumigation of storage facilities or from slow release generator pads which are positioned directly over the fruits. This treatment is very effective but it has several drawbacks such as aftertaste, bleaching and hypersensitivity to humans which took it out of the GRAS list of compounds and warranted further seek for alternatives. Prior to this research ethanol was shown to control several pathogens in different commodities including table grapes and B. cinerea. Hence it seemed to be a simple and promising technology which could offer a true alternative for storage of table grapes. Further research was however required to answer some practical and theoretical questions which remained unanswered. Major conclusions, solutions, achievements: In this research project we have shown convincingly that 30% ethanol is sufficient to prevent germination of B. cinerea and kill the spores. In a comparative study it was shown that Alternaria alternata is also rather sensitive but Rhizopus stolonifer and Aspergillus niger are less sensitive to ethanol. Consequently, ethanol protected the grapes from decay but did not have a significant effect on occurrence of mycotoxigenic Aspergillus species which are present on the surface of the berry. B. cinerea responded to ethanol or heat treatments by inducing sporulation and transient expression of the heat shock protein HSP104. Similar responses were not detected in grape berries. It was also shown that application of ethanol to berries did not induce subsequent resistance and actually the berries were slightly more susceptible to infection. The heat dose required to kill the spores was determined and it was proven that a combination of heat and ethanol allowed reduction of both the ethanol and heat dose. Ethanol and heat did not reduce the amount or appearance of the wax layers which are an essential component of the external protection of the berry. The ethanol and acetaldehyde content increased after treatment and during storage but the content was much lower than the natural ethanol content in other fruits. The efficacy of ethanol applied before harvest was similar to that of the biological control agent, Metschnikowia fructicola, Finally, the performance of ethanol could be improved synergistically by packaging the bunches in modified atmosphere films which prevent the accumulation of free water. Implications, both scientific and agricultural: It was shown that the major mode of action of ethanol is mediated by its lethal effect on fungal inoculum. Because ethanol acts mainly on the cell membranes, it was possible to enhance its effect by lowering the concentration and elevating the temperature of the treatment. Another important development was the continuous protection of the treated bunches by modified atmosphere that can solve the problem of secondary or internal infection. From the practical standpoint, a variety of means were offered to enhance the effect of the treatment and to offer a viable alternative to SO2 which could be instantly adopted by the industry with a special benefit to growers of organic grapes.   

Nitrification: an old process, a new concern

1971 ◽  
Vol 24 ◽  
Author(s):  
W. H. Verstraete
Keyword(s):  
Culture Medium ◽  
Nitrogen Sources ◽  
Living Cells ◽  
Factors Affecting ◽  
Inhibiting Effect ◽  
Proteose Peptone ◽  
Asparaginase Activity

Some  factors affecting the L-asparaginase activity of E.  aroideae were investigated. Increasing  concentrations of glucose in the culture medium had an inhibiting effect on  the production of L-asparaginase by this microorganism. Buffering of the  culture medium in order to stabilize the pH during growth resulted in a decrease  of the L-asparaginase activity. From the different nitrogen sources examined,  tryptone, proteose peptone nr 2 and nr 3 stimulated the L-asparaginase  production. Toluene treatment of the cells practically destroyed the  L-asparaginase. Acetone dried cells showed an L-asparaginase activity  comparable with the activity of living cells.

Luminescent cyclometallated platinum(ii) complexes: highly promising EGFR/DNA probes and dual-targeting anticancer agents

2018 ◽  
Vol 5 (2) ◽  
pp. 413-424 ◽  
Author(s):  
Yang Zhang ◽  
Qun Luo ◽  
Wei Zheng ◽  
Zhaoying Wang ◽  
Yu Lin ◽  
...  
Keyword(s):  
Anticancer Agents ◽  
Platinum Complexes ◽  
Living Cells ◽  
Dna Probes ◽  
High Potential ◽  
Luminescent Probes ◽  
Dual Targeting

Cyclometallated platinum complexes bearing 4-anilinoquinazolines exhibit high potential as luminescent probes for EGFR/DNA in living cells and dual-targeting anticancer agents.

The potential biocontrol agent Paenibacillus polymyxa TP3 produces fusaricidin-type compounds involved in the antagonism against gray mold pathogen Botrytis cinerea

2021 ◽  
Author(s):  
Shuen-Huang Tsai ◽  
Yu-Ting Chen ◽  
Yu-Liang Yang ◽  
Bo-Yi Lee ◽  
Chien-Jui Huang ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Botrytis Cinerea ◽  
Biological Control Agent ◽  
Imaging Mass Spectrometry ◽  
Paenibacillus Polymyxa ◽  
Field Trials ◽  
Gray Mold ◽  
Control Agent ◽  
Antagonistic Activity ◽  
New Variant

Paenibacillus polymyxa is a beneficial bacterium for plant health. Paenibacillus polymyxa TP3 exhibits antagonistic activity toward Botrytis cinerea and alleviates gray mold symptoms on the leaves of strawberry plants. Moreover, suppression of gray mold on the flowers and fruits of strawberry plants in field trials, including vegetative cells and endospores, was demonstrated, indicating the potential of strain TP3 as a biological control agent. To examine the anti-B. cinerea compounds produced by P. polymyxa TP3, matrix‐assisted laser‐desorption/ionization time‐of‐flight mass spectrometry was performed and fusaricidin-corresponding mass spectra were detected. Moreover, fusaricidin-related signals appeared in imaging mass spectrometry of TP3 when confronted with B. cinerea. By using liquid chromatography-mass spectrometry-based molecular networking approach, several fusaricidins were identified including a new variant of m/z 917.5455 with serine in the first position of the hexapeptide. Via advanced mass spectrometry and network analysis, fusaricidin-type compounds produced by P. polymyxa TP3 were efficiently disclosed and were presumed to play roles in the antagonism against gray mold pathogen B. cinerea.

scholarly journals Glass beads load macromolecules into living cells

1987 ◽  
Vol 88 (5) ◽  
pp. 669-678
Author(s):  
P.L. McNeil ◽  
E. Warder
Keyword(s):  
Culture Medium ◽  
Small Volume ◽  
Cultured Cells ◽  
Cell Monolayer ◽  
Cell Loss ◽  
Living Cells ◽  
Glass Beads ◽  
Cell Type ◽  
Large Numbers ◽  
Micron Diameter

We describe and characterize an exceptionally rapid and simple new technique for loading large numbers of cultured cells with large macromolecules. The culture medium of the cell monolayer is replaced by a small volume of the macromolecule to be loaded. Glass beads (75–500 micron diameter) are then sprinkled onto the cells, the cells are washed free of beads and exogenous macromolecules, and ‘bead-loading’ is completed. The conditions for bead-loading can readily be modified to accommodate cell type and loading objectives: for example, the amount of loading per cell increases if bead size is increased or if beads are agitated after sprinkling onto the monolayer, but at the expense of increased cell loss. As many as 97% of a population of bovine aortic endothelial (BAE) cells were loaded with a 10,000 Mr dextran; and 79% with a 150,000 Mr dextran using bead-loading. Various cell lines have been loaded using glass beads. Moreover, bead-loading has the advantage of producing loaded cells that remain adherent and well-spread, thus minimizing recovery time and permitting immediate microscopic examination.

Effect of nitrous oxide against Botrytis cinerea and phenylpropanoid pathway metabolism in table grapes

2019 ◽  
Vol 254 ◽  
pp. 99-105 ◽  
Author(s):  
Jing Xu ◽  
Zheng Zhang ◽  
Xueping Li ◽  
Jia Wei ◽  
Bin Wu
Keyword(s):  
Nitrous Oxide ◽  
Botrytis Cinerea ◽  
Phenylpropanoid Pathway ◽  
Table Grapes

Experiments in Nanomechanical Properties of Live Osteoblast Cells and Cell–Biomaterial Interface

2011 ◽  
Vol 2 (4) ◽  
Author(s):  
Rohit Khanna ◽  
Kalpana S. Katti ◽  
Dinesh R. Katti
Keyword(s):  
Cell Culture ◽  
Culture Medium ◽  
Cell Structure ◽  
Living Cells ◽  
Actin Stress Fiber ◽  
Cell Culture Medium ◽  
Nanomechanical Properties ◽  
Cell Substrate ◽  
Significant Difference

Characterizing the mechanical characteristics of living cells and cell–biomaterial composite is an important area of research in bone tissue engineering. In this work, an in situ displacement-controlled nanoindentation technique (using Hysitron Triboscope) is developed to perform nanomechanical characterization of living cells (human osteoblasts) and cell–substrate constructs under physiological conditions (cell culture medium; 37 °C). In situ elastic moduli (E) of adsorbed proteins on tissue culture polystyrene (TCPS) under cell culture media were found to be ∼4 GPa as revealed by modulus mapping experiments. The TCPS substrates soaked in cell culture medium showed significant difference in surface nanomechanical properties (up to depths of ∼12 nm) as compared to properties obtained from deeper indentations. Atomic force microscopy (AFM) revealed the cytoskeleton structures such as actin stress fiber networks on flat cells which are believed to impart the structural integrity to cell structure. Load-deformation response of cell was found to be purely elastic in nature, i.e., cell recovers its shape on unloading as indicated by linear loading and unloading curves obtained at 1000 nm indentation depth. The elastic response of cells is obtained during initial cell adhesion (ECell, 1 h, 1000 nm = 4.4–12.4 MPa), cell division (ECell, 2 days, 1000 nm = 1.3–3.0 MPa), and cell spreading (ECell, 2 days, 1000 nm = 6.9–11.6 MPa). Composite nanomechanical responses of cell–TCPS constructs were obtained by indentation at depths of 2000 nm and 3000 nm on cell-seeded TCPS. Elastic properties of cell–substrate composites were mostly dominated by stiff TCPS (EBulk = 5 GPa) lying underneath the cell.

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