RESUMEN
Postharvest treatment with high-pressure CO2 helps to control decay and increase firmness in strawberries. Increases in firmness occurred through modification of calcium binding to cell wall. However, the mechanism(s) involved in Ca(2+) migration to pectic polymers and other physiological events associated with the maintenance of increased firmness are not clearly understood. The focus of this study was to find potential mechanism(s) that are associated with calcium movement, increases in firmness, or maintenance of firmness in strawberry fruit after high-pressure CO2 treatment. An increase in firmness was induced by high-pressure CO2 treatment, but not by high-pressure N2 treatment. This indicates that CO2 stimulates a change in firmness. The increase in firmness induced by high-pressure CO2 seems to involve calcium efflux. Using membrane Ca(2+) -dependent ATPase inhibitors sodium vanadate (250 µM) and erythrosin B (100 µM) delayed both the increase in firmness and calcium binding to wall polymers. Exogenous application of CaCl2 (10 mM) enhanced the firmness increase of fruit slices only when they were exposed to high-pressure CO2 . The activity of pectate lyase was downregulated by CO2 treatment, but ß-galactosidase activity was not affected. The increase in strawberry firmness induced by high-pressure CO2 treatment primarily involves the efflux of calcium ions and their binding to wall polymers. These physiological changes are not induced by an anaerobic environment. The downregulation of wall-modifying enzymes, such as pectate lyase, appeared to contribute to the maintenance of firmness that was induced by high-pressure CO2 treatment.
Asunto(s)
Calcio/metabolismo , Dióxido de Carbono/farmacología , Pared Celular/metabolismo , Fragaria/enzimología , Frutas/enzimología , Dureza , Polisacárido Liasas/metabolismo , Calcio/farmacología , Cloruro de Calcio/metabolismo , Cloruro de Calcio/farmacología , Fragaria/metabolismo , Frutas/metabolismo , Humanos , Iones/metabolismo , PresiónRESUMEN
Two species, Penicillium adametzioides and Purpureocillium lilacinum, were isolated from decayed grapes (cv. Cheongsoo) in Korea. Each species was initially identified by phylogenetic analysis of a combined dataset of two genes. Internal transcribed spacer (ITS) and ß-tubulin (BT2) genes were used for identification of Penicillium adametzioides, and ITS and partial translation elongation factor 1-α (TEF) genes were used for identification of Purpureocillium lilacinum. Morphologically, they were found to be identical to previous descriptions. The two species presented here have not been previously reported in Korea.
RESUMEN
During 2007 survey of post-harvest diseases of yam performed in May and June, severe tuber loss caused by blue mold was observed in Iksan, Cheonbuk Province. Two species of Penicillium were isolated from the infected tubers. Based on ß-tubulin gene sequence analysis, and cultural and morphological characteristics, the isolates were identified as Penicillium sclerotigenum and P. polonicum. P. sclerotigenum, which is a novel to Korea, is presently described and illustrated.