High Light Acclimation Mechanisms Deficient in a PsbS-Knockout Arabidopsis Mutant.

The photosystem II PsbS protein of thylakoid membranes is responsible for regulating the energy-dependent, non-photochemical quenching of excess chlorophyll excited states as a short-term mechanism for protection against high light (HL) stress. However, the role of PsbS protein in long-term HL acclimation processes remains poorly understood. Here we investigate the role of PsbS protein during long-term HL acclimation processes in wild-type (WT) and npq4-1 mutants of Arabidopsis which lack the PsbS protein. During long-term HL illumination, photosystem II photochemical efficiency initially dropped, followed by a recovery of electron transport and photochemical quenching (qL) in WT, but not in npq4-1 mutants. In addition, we observed a reduction in light-harvesting antenna size during HL treatment that ceased after HL treatment in WT, but not in npq4-1 mutants. When plants were adapted to HL, more reactive oxygen species (ROS) were accumulated in npq4-1 mutants compared to WT. Gene expression studies indicated that npq4-1 mutants failed to express genes involved in plastoquinone biosynthesis. These results suggest that the PsbS protein regulates recovery processes such as electron transport and qL during long-term HL acclimation by maintaining plastoquinone biosynthetic gene expression and enhancing ROS homeostasis.

Drug-Induced Anaphylaxis in a Vietnamese Pharmacovigilance Database: Trends and Specific Signals from a Disproportionality Analysis.

INTRODUCTION: Despite the numerous studies investigating drug-induced anaphylaxis (DIA), understanding and quantitative data analysis in developing countries remain limited. The aim of our study is to describe and quantify DIA using the National Pharmacovigilance Database of Vietnam (NPDV). METHODS: Spontaneous reporting of adverse drug reactions (ADRs) recorded between 2010 and 2016 were retrospectively analysed to identify DIA reports. The trend and characteristics of DIA cases were described. Multivariate disproportionality analysis was used for signal generation. RESULTS: Overall, 4873 DIA cases (13.2% of total ADRs) were recorded in the NPDV, 111 of which resulted in death (82% of total ADR-induced deaths) over a 7-year period. There was a remarkable increase in DIA reporting over time (p < 0.001). The incidence rates of DIA reporting per total ADRs and per 100,000 inhabitants remained high (mean rates [95% CI] of 12.06 [9.88-14.24] and 0.77 [0.33-1.20], respectively). Concerning suspected drugs, systemic antibiotics (n = 3318, 68%) were mostly reported with a reporting odds ratio (ROR) and 95% CI of 2.35 [2.20-2.51]. In the case of antibiotic-induced anaphylaxis, the third-generation cephalosporins were predominant (n = 1961, 40.2%, ROR 2.39 [2.24-2.55]). We also noted drugs generally associated with DIA such as contrast agents (ROR 2.43 [2.04-2.88]) and anaesthetics (ROR 4.02 [3.30-4.89]). Furthermore, unexpected signals were observed for alpha-chymotrypsin (ROR 1.75 [1.23-2.44]) and amoxicillin/sulbactam (ROR 1.59 [1.18-2.10]), uncommonly reported in western countries. CONCLUSION: In recent years, cases of drug-induced DIA have increased in Vietnam, mostly due to antibiotics and third-generation cephalosporins. The inappropriate use of these drugs should be taken into account. Our findings also highlighted typical Vietnamese signals for alpha-chymotrypsin- and amoxicillin/sulbactam-induced anaphylaxis, which may relate to a specific sociological context in resource-limited countries.