Untitled

Abstract

The CO2 evolution of intact potato tubers (Solanum tuberosum, L., var. "Bintje") was analyzed during a 10-day period of their warm (25 +/- 2 degrees C) or cold (5 +/- 1 degrees C) storage, to evaluate cold-stress effects on expression and activities of plant uncoupling mitochondrial protein (PUMP) and alternative oxidase (AOX). CO2 evolution rates were analyzed at 20 degrees C, to reflect their possible capacities. The 20 degrees C CO2 production declined from 13 to 8 mg kg(-1) h(-1) after 2 days of warm storage and then (after 3 to 7 days) decreased from 8 to 6.5 mg kg(-1) h(-1). In contrast, 20 degrees C CO2 evolution did not change after the first day of cold storage, increased up to 14.5 mg kg(-1) h(-1) after 2 days, and decreased to about 12 mg kg(-1) h(-1) after 3 to 7 days of cold storage. Cold storage increased PUMP expression as detected by Western blots and led to elevated capacities of both PUMP (44%) and CN-resistant AOX (10 times), but not the cytochrome pathway. Since we found that cold storage led to about the same mitochondrial respiration of 40 nmol O2 min(-1) mg(-1) attributable to each of the respective proteins, we conclude that both AOX and PUMP equally contribute to adaptation of potato tubers to cold.

Activation and Function of Mitochondrial Uncoupling Protein in Plants

“…First, UCP1 is one of the most abundant inner mitochondrial membrane proteins in Arabidopsis mitochondria (27). Second, in a number of different plant species, UCP gene expression or protein abundance is increased during a variety of stresses (4,18,28,29). Taken together with the results presented in this article, the available evidence supports the view that the capacity of UCP is sufficient to prevent oxidative damage under optimal conditions, but additional UCP protein may be required to minimize oxidative damage under stress conditions.…”

“…In the former, the storage history of the tubers is unknown, but it is likely that they had undergone a considerable period of cold storage. Since cold storage is known to induce UCP protein content in potato tubers (18), it may be that there is an increased UCP content in the supermarket potatoes in comparison to the greenhouse potatoes, and this could be responsible for the greater effect of HNE and transretinal in mitochondria from the former. This hypothesis was confirmed when the UCP content of mitochondria from the respective potatoes was examined by Western blot (Fig.…”

Efecto de las condiciones de operación en los cambios fisicoquímicos y fisiológicos de frutas mínimamente procesadas por deshidratación osmótica

“…En el caso concreto del CO 2 , los analizadores de gases de infrarrojos se han utilizado para la determinación de la respiración de vegetales (Calegario et al, 2001).…”