Reactive Oxygen Species, Lipid Peroxidation and Antioxidative Defense Mechanism

Lipid peroxidation can be defined as the oxidative deterioration of lipids containing any number of carbon-carbon double bonds. Lipid peroxidation is a well-established mechanism of cellular injury in both plants and animals, and is used as an indicator of oxidative stress in cells and tissues. Lipid peroxides are unstable and decompose to form a complex series of compounds including reactive carbonyl compounds. The oxidation of linoleates and cholesterol is discussed in some detail. Analytical methods for studying lipid peroxidation were mentioned. Various kinds of antioxidants with different functions inhibit lipid peroxidation and the deleterious effects caused by the lipid peroxidation products.

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What Does Productivity Really Mean? Towards an Integrative Paradigm in the Search for Biodiversity-Productivity Relationships

How species diversity relates to productivity remains a major debate. To date, however, the underlying mechanisms that regulate the ecological processes involved are still poorly understood. Three major issues persist in early efforts at resolution. First, in the context that productivity drives species diversity, how the pathways operate is poorly-explained. Second, productivity  per se varies with community or ecosystem maturity. If diversity indeed drives productivity, the criterion of choosing appropriate measures for productivity is not available. Third, spatial scaling suggests that sampling based on small-plots may not be suitable for formulating species richness-productivity relationships (SRPRs). Thus, the long-standing assumption simply linking diversity with productivity and pursuing a generalizing pattern may not be robust. We argue that productivity, though defined as ‘the rate of biomass production’, has been measured in two ways environmental surrogates and biomass production leading to misinterpretations and difficulty in the pursuit of generalizable SRPRs. To tackle these issues, we developed an integrative theoretical paradigm encompassing richer biological and physical contexts and clearly reconciling the major processes of the systems, using proper productivity measures and sampling units. We conclude that loose interpretation and confounding measures of productivity may be the real root of current SRPR inconsistencies and debate.

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Breeding for Chlorogenic Acid Content in Eggplant: Interest and Prospects

Chlorogenic acid (5-O-caffeoyl-quinic acid; CGA) is an ester of caffeic acid and (-)-quinic acid with many beneficial properties for human health, such as anti-oxidant, anti-inflammatory, cardioprotective, anti-carcinogenic, anti-obesity, and anti-diabetic properties. This has raised an interest for the development of new crop cultivars with increased CGA content. One of the crops with higher CGA content is eggplant (Solanum melongena). There is a wide diversity for CGA content in cultivated eggplant germplasm, which is influenced by the fruit developmental stage, storage conditions, and environmental factors. Therefore, appropriate experimental designs are required for an efficient breeding. Several strategies are proposed for breeding for high CGA content such as intraspecific variation, selection among accessions, development of hybrids and lines with good agronomic and commercial characteristics, or introgression of the high CGA trait in élite lines. Some wild relatives, like S. incanum, present higher CGA contents than those of eggplant. Interspecific hybridization can be used to introgress favorable alleles from the wild species into the genetic background of cultivated eggplant. Fruit flesh browning, as a result of CGA oxidation by polyphenol oxidases, could be a side effect of increasing the CGA content in eggplant. However, experimental results indicate that the relationship between CGA content and fruit flesh browning is low or moderate. Furthermore, selection for low polyphenol oxidase activity might result in reduced fruit flesh browning. Overall, the available data suggest that the development of eggplant cultivars with improved functional quality resulting from a higher CGA content is feasible.

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