Cellular damage induced by a sequential oxidative treatment on Penicillium digitatum

Abstract

Aim: To investigate the cellular damage on Penicillium digitatum produced by a sequential oxidative treatment (SOT), previously standardized in our laboratory, to prevent the conidia growth. Lethal SOT consists of 2‐min preincubation with 10 ppm NaClO followed by 2‐min incubation with 6 mmol l−1 CuSO4 and 100 mmol l−1 H2O2 at 25°C. Methods and Results: After the application of lethal SOT or sublethal SOT (decreasing only the H2O2 concentration), we analysed several conidia features such as germination, oxygen consumption, ultrastructure and integrity of the cellular wall and membrane. Also, we measured the production of reactive oxygen species (ROS) and the content of thiobarbituric acid‐reactive species (TBARS). With the increase of H2O2 concentration in the SOT, germination and oxygen consumption of conidia became inhibited, while the membrane permeability, ROS production and TBARS content of conidia increased. Several studies revealed ultrastructural disorganization in P. digitatum conidia after lethal SOT, showing severe cellular damage without apparent damage to the cell wall. In addition, mycelium of P. digitatum was more sensitive than conidia to the oxidative treatment, because growth ceased and permeability of the membranes increased after exposure of the mycelium to a SOT with only 50 mmol l−1 H2O2 compared to a SOT of 100 mmol l−1 for these effects to occur on conidia. Conclusion: Our insights into cellular changes produced by the lethal SOT are consistent with the mode of action of the oxidant compounds, by producing both alteration of membrane integrity and intracellular damage. Significance and Impact of the Study: Our results allow the understanding of SOT effects on P. digitatum, which will be useful to develop a reliable treatment to control postharvest diseases in view of its future application in packing houses.

Cold Plasma for Effective Fungal and Mycotoxin Control in Foods: Mechanisms, Inactivation Effects, and Applications

“…30 s); subsequent treatment results in complete inactivation. At low doses, fungal cells could undergo apoptosis (Hashizume et al., ). Drastic morphological change of the cellular structures is not a necessity for fungal inactivation. However, intracellular nanostructural changes will be evident. Morphological changes, if they occur, can be observed as distinct changes in the cell membrane and increase in its permeability (Cerioni, Volentini, Prado, Rapisarda, & Rodriguez‐Montelongo, ; Dasan, Mutlu, & Boyaci, ; Kang et al., ). The ROS from plasma cause oxidation of intracellular organelles; particularly, lipid phosphates are oxidized by ROS to lipid peroxide through a chain reaction. In later stages, the oxidation of genomic DND and cellular proteins may also occur (Kang et al., ; Lu, Liu, Song, Zhou, & Niu, ; Panngom et al., ).…”

The role of oxidative stress in the growth of the indoor moldCladosporium cladosporioidesunder water dynamics

“…Cellular H 2 O 2 concentration was calculated in accordance with the standard curve with subtraction of the background. The determined H 2 O 2 concentration was then normalized with the protein concentration present in the samples . The method for the quantification of protein concentration is described in Section 2.6.…”

UVA Photoactivation of Harmol Enhances Its Antifungal Activity against the Phytopathogens Penicillium digitatum and Botrytis cinerea

“…Afterward, samples were prepared as described by Cerioni et al (2010). Observations were made with a Zeiss EM 109 transmission electron microscope from CIME (Centro Integral de Microscopía Electrónica, CONICET-UNT).…”

“…Cell wall integrity was studied using the fluorescent dye Calcofluor White (CFW; Pringle, 1991), following a protocol adapted by Cerioni et al (2010). Controls were performed in parallel, treating conidial suspensions with DMSO.…”

“…After 24 h of incubation, suspensions were washed and resuspended in sterile distilled water. Reactive oxygen species (ROS) were determined with the H 2 DCFDA probe (Davidson et al, 1996; Halliwell and Whiteman, 2004), following the protocol adapted by Cerioni et al (2010).…”