Academic literature on the topic 'Chemical elicitation'

Biocontrol agents (BCAs) based on plant growth promoting rhizobacteria have recently been developed as alternatives to chemical pesticides. Among those beneficial bacteria, Bacillus spp. are one of the most promising BCAs. A wide range of bioactive secondary metabolites (BSMs) are involved in biocontrol via antibiosis to phytopathogens and/or via elicitation of systemic resistance in their host plants. This chapter illustrates the diversity of pathosystems in which BCA based on Bacillus spp. have proved effective. It describes the mechanisms underpinning this biocontrol activity via production of a wide range of enzymes, proteins and small-size BSMs. As these BSMs are clearly involved in pathogen control, we emphasise the importance of understanding the ecological factors influencing their production. In the last part of the chapter, we highlight the potential interactions between Bacillus spp. and other soil microorganisms in developing consortia of biocontrol agents combining species with synergistic activities for plant health improvement.

The plant kingdom is considered the most important source of medicinal chemicals. In vitro culture techniques are being considered a promising alternative to traditional agricultural processes to improve medicinal plants multiplication and their production of pharmaceutical compounds. In this chapter, several in vitro culture strategies are discussed to improve secondary metabolites production, including (1) plant kingdom as a source of medicinal chemicals, (2) in vitro culture of medicinal plants, (3) culture media optimization, (4) application of suspension cell culture for production of secondary metabolites, (5) elicitation to enhance the productivity of the culture, (6) precursor intermediates feeding, (7) selection of high-yielding cell lines, (8) overexpression of genes that control the production of bioactive compounds, and (9) scale-up production. Also, challenges that hinder the in vitro culture of medicinal plants using different techniques and the use of those techniques to produce pharmaceutical compounds are discussed in this chapter, including (a) secondary metabolites toxicity, (b) low growth rate, (c) culture browning, (d) limitation in the application of transformation, (e) somaclonal variation, and (f) vitrification. Therefore, the principal objective of the current chapter was to shed light on the studies on some medicinal plants and the used protocols to overcome some difficulties in terms of in vitro propagation that maximize their economic values.

Site cleanup decisions involve developing action levels and residual limits for key contaminants, to assure health protection during the cleanup period and into the long term. Uncertainty is inherent in the toxicity information used to define these levels, based on incomplete scientific knowledge regarding dose-response relationships across various hazards and exposures at environmentally relevant levels. This problem can be addressed by applying principles used to manage uncertainty in operations research, as illustrated by the newsboy dilemma. Each day a newsboy must balance the risk of buyi