Optimizing Rubisco and its regulation for greater resource use efficiency

Rubisco catalyses the carboxylation of ribulose-1,5-bisphosphate (RuBP), enabling net CO2 assimilation in photosynthesis. The properties and regulation of Rubisco are not optimal for biomass production in current and projected future environments. Rubisco is relatively inefficient, and large amounts of the enzyme are needed to support photosynthesis, requiring large investments in nitrogen. The competing oxygenation of RuBP by Rubisco decreases photosynthetic efficiency. Additionally, Rubisco is inhibited by some sugar phosphates and depends upon interaction with Rubisco activase (Rca) to be reactivated. Rca activity is modulated by the chloroplast redox status and ADP/ATP ratios, thereby mediating Rubisco activation and photosynthetic induction in response to irradiance. The extreme thermal sensitivity of Rca compromises net CO2 assimilation at moderately high temperatures. Given its central role in carbon assimilation, the improvement of Rubisco function and regulation is tightly linked with irradiance, nitrogen and water use efficiencies. Although past attempts have had limited success, novel technologies and an expanding knowledge base make the challenge of improving Rubisco activity in crops an achievable goal. Strategies to optimize Rubisco and its regulation are addressed in relation to their potential to improve crop resource use efficiency and climate resilience of photosynthesis

Predicting Psychological Distress Among Former Soviet Immigrants

This study investigated whether age, gender, marital status, education, employ ment, length of time in the U.S. and immigration demands (novelty, occupation, language, discrimination, loss, and not feeling at home) were predictors of psychological distress in a sample of 1,647 former Soviet immigrants. Multiple regression analysis indicated that the combined model of demographic and demand of immigration variables was significant. Results indicated that women, older immigrants, those with less than a college education, and those with greater immigration demands related to novelty, language, discrimination, loss, and not feeling at home were most distressed