Immunological and molecular probes to detect phytoplankton responses to environmental stress in nature

Recent advances in using immunological and nucleic acid probes to detect th e effects of environmental stress on phytoplankton growth rate and yield ar e reviewed here. The rationale for this approach is discussed in the contex t of the general response observed from microorganisms grown under stress i mposed by various environmental factors. Retrenchment, or the observed down -regulation of metabolic processes under nutrient deficiency, is categorize d as a general response that is of limited use in designing probes to stres s induced by a specific nutrient. In contrast, compensation and the increas e capacity for nutrient acquisition are specific responses that appear more promising for the development of such probes. Methods and approaches used to design immunological and nucleic acid probes for stress imposed by nutri ent deficiency are reviewed. Specific examples for iron and nitrogen limita tion are presented to demonstrate the potential use of nutrient stress indi cators in natural populations of phytoplankton. Finally, the limitations of this approach and the importance of understanding the regulation of the ge nes and proteins used to prepare the probes are emphasized.