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H 2 O 2 affects the expression of genes that are involved in plant responses to diverse environmental stresses; however, the underlying mechanisms remain elusive. Here, we demonstrate that H 2 O 2 enhances plant freezing tolerance through its effect on a protein product of low expression of osmotically responsive genes2 (LOS2). LOS2 is translated into a major product, cytosolic enolase2 (ENO2), and sometimes an alternative product, the transcription repressor c-Myc-binding protein (MBP-1). ENO2, but not MBP-1, promotes cold tolerance by binding the promoter of C-repeat/DRE binding factor1 (CBF1), a central transcription factor in plant cold signaling, thus activating its expression. Overexpression of CBF1 restores freezing sensitivity of a LOS2 loss-of-function mutant. Furthermore, cold-induced H 2 O 2 increases nuclear import and transcriptional binding activity of ENO2 by sulfenylating cysteine 408 and thereby promotes its oligomerization. Collectively, our results illustrate how H 2 O 2 activates plant cold responses by sulfenylating ENO2 and promoting its oligomerization, leading to enhanced nuclear translocation and transcriptional activation of CBF1. [Display omitted] • H 2 O 2 confers plant freezing tolerance under cold-acclimated conditions • ENO2 promotes plant cold response by binding to and activating CBF1 • H 2 O 2 sulfenylation at ENO2 Cys408 is involved in plant freezing tolerance • Cold-induced H 2 O 2 triggers ENO2 oligomerization and nuclear import Liu et al. examine the role of H 2 O 2 in the plant cold response. They find that H 2 O 2 , through sulfenylation that promotes the oligomerization of ENO2, enhances ENO2 nuclear translocation and transcriptional binding activity. ENO2 in turn upregulates the expression of the cold response regulator CBF1 , thus promoting freezing tolerance. [ABSTRACT FROM AUTHOR]

The feasibility of computational fluid dynamics (CFD) to evaluate airflow characteristics in different head and neck positions has not been established. This study compared the changes in volume and airflow behavior of the upper airway by CFD simulation to predict the influence of anatomical and physiological airway changes due to different head–neck positions on mechanical ventilation. One awake volunteer with no risk of difficult airway underwent computed tomography in neutral position, extension position (both head and neck extended), and sniffing position (head extended and neck flexed). Three-dimensional airway models of the upper airway were reconstructed. The total volume ( V ) and narrowest area ( A min ) of the airway models were measured. CFD simulation with an Spalart–Allmaras model was performed to characterize airflow behavior in neutral, extension, and sniffing positions of closed-mouth and open-mouth ventilation. The comparison result for V was neutral