Search

Abstract: In this paper, a DSC and Raman study of hydrated multilamellar DMPC (1,2-dimyristoyl-sn-glycero-3-phosphocholine) and DMPE (1,2-dimyristoyl-sn-glycero-3-phosphoethanolamine) liposomes in presence of increasing amounts of DDT is reported. The observed changes denote that DDT molecules interact with both phospholipids and that the interaction mainly involves the external part of the bilayer since the deep penetration into the hydrophobic core is prevented by the setting up of polar interactions between the three aliphatic C–Cl bonds of the trichloro group of DDT and the –N+(CH3)3 of DMPC or the –NH3 + groups of DMPE molecules. This behaviour was particularly evidenced in presence of DMPE, as the insertion of DDT molecules into the central part of the bilayer seems to be completely excluded. Moreover, in DMPE liposomes the overall structure of the bilayer changes to a well defined and structured ‘phase II’ in presence of even small DDT amounts. [Copyright &y& Elsevier]

• Neofusicoccum parvum is representing an emerging problem for apple productions. • L1 and L8 strains are able to completely inhibit pathogen sporification in wood. • Both strains reduced by 70% pathogen mycelial growth through non volatile compounds. • L8 was able to increase cellulose content in wood preventing a fast fungal attack. Aureobasidium pullulans strains L1 and L8 were used as an alternative strategy against Neofusicoccum parvum , pathogen of apple wood and fruit. Both strains displayed a great ability to reduce pathogen conidia germination of almost 50% and totally stop its sporification in wood of 'Gala' and 'Fuji' apple cultivars. In addition, by in vitro tests the antagonistic activity displayed by non-volatile metabolites produced by both yeasts was highlighted by 70% of reduction of the pathogen mycelial growth. On apple fruit, the pathogen severity was reduced by 66% and 50% in 'Gala', and 70% and 60% in 'Fuji' by L1 and L8 respectively. In wood, no statistical differences were observed between L1, L8 and the control, except for 'Fuji' wood, where L8 strain displayed a wood lesion reduction of 23% with respect to the untreated control. Infrared analysis showed how the presence of both strains on woody tissues helped preserving cellulose content, preventing in this way the faster wood degradation by the pathogen. In addition, L1 and L8 simply colonized the wood surface, probably displaying an endophytic attitude, an essential requirement for controlling N. parvum in field. [ABSTRACT FROM AUTHOR]

• Bacterial strains can represent a sustainable solution to preserve kiwifruit from skin pitting. • On kiwifruit, P. synxantha (117-2b) was the most effective strain against C. luteo-olivacea. • Antifungal compounds in the form of peptides were mainly detected by FT-IR analysis. • By qPCR analysis, C. luteo-olivacea showed great persistence in kiwifruit despite the treatments. Skin pitting currently represents one of the major postharvest diseases of kiwifruit and one of the most difficult to manage in packinghouses due to its latent behavior and the difficulty in predicting its emergence. Our research demonstrates the potential to use different bacterial strains (Pseudomonas synxantha and Bacillus spp.) instead of synthetic compounds to preserve kiwifruit from the development of postharvest skin pitting symptoms, following the momentum towards sustainable strategies. The antagonists tested with in vitro assays showed different efficacy rates against C. luteo-olivacea (strain Cad21) mycelial growth by producing non-volatile metabolites. The biochemical composition of the most active bacterial non-volatile secondary metabolites was described through FT-IR (Fourier-Transform Infrared) spectroscopy. Pseudomonas synxantha strain 117-2b emerged as the most active strain in in vivo experiments, both as a curative and preventive treatment (63% and 84.7% of inhibition, respectively). In addition to its ability to reduce disease incidence, the biological antagonism exerted by P. synxantha strain 117-2b was further demonstrated by qPCR analysis as a reduction in the pathogen's abundance. In view of these results, alternative solutions in the field and during postharvest storage could be considered to control C. luteo-olivacea of kiwifruit. [ABSTRACT FROM AUTHOR]