The control of postharvest blue and green molds of citrus in relation with essential oil-wax formulations, adherence and viscosity.

in Postharvest Biology & Technology (2012), 73

The use of wax coatings enriched with antifungals has significantly contributed to quality maintaining of harvested citrus fruit. On the other hand, interest in essential oils (EOs) as an alternative to ... [more ▼]

The use of wax coatings enriched with antifungals has significantly contributed to quality maintaining of harvested citrus fruit. On the other hand, interest in essential oils (EOs) as an alternative to synthetic fungicides has recently gained momentum. In this study, Cinnamomum zeylanicum EO was incorporated into a variety of commercial citrus waxes (shellac, carnauba, paraffin and polyethylene). The biological activity of these formulations against green and blue rots as well as their viscosity and adherence to the orange fruit surface were evaluated. Excellent disease control was achieved with C. zeylanicum EO incorporated in shellac and/or carnauba wax compared to other EO–wax formulations. Disease control by EO–waxes seems to depend not only on the volume that remains on the fruit skin, but also, probably on the retention of EO components on the fruit. Other factors such as formulation solubility, permeability to gases, and compatibility between EO compounds and those of waxes may also be involved in the improvement of EO efficacy. The present study may therefore allow a careful selection of ppropriate waxes for the elaboration of effective EO–wax formulations. [less ▲]

Characterization of a novel chitinase from a moderately halophilic bacterium, Virgibacillus marismortui strain M3-23

in Annals of Microbiology (2012), 62(2), 835-841

A new chitinase produced by the moderately halophilic bacterium Virgibacillus marismortui strain M3- 23 was identified and characterized. Distinguishable characteristics of high activity and stability at ... [more ▼]

A new chitinase produced by the moderately halophilic bacterium Virgibacillus marismortui strain M3- 23 was identified and characterized. Distinguishable characteristics of high activity and stability at different pH, temperatures and salinity of M3-23 chitinase are reported. Analysis of the catalytic domain sequence from the enzyme highlighted its relationship to glycosyl hydrolase family 18. Comparison of the deduced chitinase sequence from strain M3-23 to known chitinases from Bacillus species showed low similarity (82%), suggested its novelty. This is the first report of the characterization of chitinase from the species V. marismortui. The halo- and thermo-tolerant nature of the chitinolytic enzyme allows its potential use in agricultural and industrial applications. [less ▲]

Evaluation of two protein extraction protocols for Pichia anomala proteome analysis.

Poster (2009, May 19)

Pichia anomala (strain Kh6) was isolated from the surface of apple fruits and selected for its high and reliable biocontrol activity against Botrytis cinerea and Penicillium expansum. Its main modes of ... [more ▼]

Pichia anomala (strain Kh6) was isolated from the surface of apple fruits and selected for its high and reliable biocontrol activity against Botrytis cinerea and Penicillium expansum. Its main modes of action have until now been studied using essentially microbiological and molecular approaches. The study continues now using the proteomic approach and considering the in situ P. anomala/B. cinerea/apple interaction. Two-dimensional polyacrylamide gel electrophoresis (2-D PAGE) is one of the most powerful tools used for proteomic analysis. It combines two sequential separation steps, the first dimension via isoelectric focusing (IEF) and the second one by SDS PAGE. Although recent advances in 2-D PAGE, the extraction of the whole proteome and the removal of interfering contaminants still limit its application. Sample preparation constitutes indeed a critical influential step for IEF which in turn affects 2-D gel quality. The objective of the present work was thus to develop an effective protein extraction protocol designed for 2-D PAGE analysis of the proteome of P. anomala strain Kh6. As a starting point, two contrasting protein extraction protocols were chosen to be evaluated in terms of protein yield and one-dimensional (1-D) SDS PAGE and 2-D PAGE gel patterns. The first protocol uses a urea/thiourea-based lysis buffer whereas the second protocol utilizes a hot SDS-based lysis buffer with an additional precipitation step. The comparison model used consisted of apples treated with strain Kh6 alone (K) and apples first treated with Kh6 and then inoculated with B. cinerea conidia (KB). Growth kinetics of strain Kh6 on wounded apples was determined and found to be not affected by the presence of B. cinerea conidia. Proteins were extracted from yeast pellets collected at both the exponential and stationary phases of strain Kh6 growth on apples. The evaluation of both extraction protocols indicates that more proteins were extracted with the SDS protocol and, according to 1-D assays, higher molecular weight proteins were obtained with the ‘urea/thiourea’ protocol and, regardless of the protocol used, more bands were obtained during the exponential phase. 2-D assays are currently underway and the corresponding results will be presented. [less ▲]

cDNA-AFLP analysis of Candida oleophila (strain O) genes differentially expressed during the biocontrol of Botrytis cinerea on harvested apples

in Bulletin OILB/SROP = IOBC/WPRS Bulletin (2009), 43