Contribution of the Alternative Respiratory Pathway to PSII Photoprotection in C3 and C4 Plants

The mechanism by which the mitochondrial alternative oxidase （AOX） pathway contributes to photosystem II （PSII） photoprotection is in dispute. It was generally thought that the AOX pathway protects photosystems by dissipating excess reducing equivalents exported from chloroplasts through the malate/oxaloacetate （Mal/OAA） shuttle and thus preventing the over-reduction of chloroplasts. In this study, using the aoxla Arabidopsis mutant and nine other C3 and C4 plant species, we revealed an additional action model of the AOX pathway in PSII photoprotection. Although the AOX pathway contributes to PSII photoprotection in C3 leaves treated with high light, this contribution was observed to disappear when photorespiration was suppressed. Disruption or inhibition of the AOX pathway significantly decreased the photorespiration in C3 leaves. Moreover, the AOX pathway did not respond to high light and contributed little to PSII photoprotection in C4 leaves possessing a highly active Mal/OAA shuttle but with little photorespiration. These results demonstrate that the AOX pathway contributes to PSII photoprotection in C3 plants by maintaining photo- respiration to detoxify glycolate and via the indirect export of excess reducing equivalents from chloro-plasts by the MaI/OAA shuttle. This new action model explains why the AOX pathway does not contribute to PSII photoprotection in C4 plants.

Chinese Expert Consensus on Clinical Application of Patch Test (Revised 2020)

Allergic contact dermatitis is a common clinical allergic disease.The patch test is the gold standard for finding and clarifying contact allergens.With the deepening understanding of the epidemiology,pathogenesis,and clinical manifestations of contact dermatitis,as well as the increased requirements for the standardized application of patch tests,the relevant consensus needs to be continuously updated.This consensus is updated on the basis of the version issued in 2015.In this revised version,it refines the selection of clinical indications,improves the judgment end interpretation of results,adds delayed detection and patient education,and so on,which aims to further standardize clinical applications and improve the value of patch test.

Nevus Sebaceous at an Unusual Location： A Rare Presentation

To the Editor： Nevus sebaceous （NS） is an epidermal nevus that is comprised predominantly of sebaceous glands in approximately 0.3% of newborns.[1] Clinically, it presents as a single or, less commonly, multiple yellowish-colored plaques with overlying alopecia, usually confined on the scalp; however, it can also appear on the face, preauricular area, and neck region.[2,3] Here, we reported a case of NS in a discrete linear pattern located on the left chest region, in contrast with typical cases, to assist physicians in the early diagnosis of this condition and to prevent unnecessary examinations and inadequate therapeutic interventions.