Cation channels are involved in brassinosteroid signalling in higher plants

Brassinosteroids (BRs) are an important class of plant hormones with a multitude of functions. They have been intensively investigated for their biosynthesis, distribution and physiological functions. The aim of this study was to examine possible effects of {BRs} on the plant plasma membrane cation conductances and Ca2+ signalling. The wheat root protoplasts (tested by patch-clamping) and excised arabidopsis roots (analysed by Ca2+-aequorin chemiluminometry), were used. In the whole-cell plasma membrane patches, 24-epibrassinolide, 28-homobrassionolide or 24-epicastasterone (1 ?M) were applied exogenously. 24-Epicastasterone increased the activity of the K+ efflux conductance in 50 of tested protoplasts while 24-epibrassonolide and 28-homobrassionolide did not modify the plasma membrane currents. Addition of 24-epicastasterone at the cytosolic side (to the pipette solution) resulted in dramatic stimulation of a time-dependent K+ efflux current (in 30 of protoplasts) and an activation of Ca2+ influx currents (in 30 of protoplasts). Gadolinium ions, which are blockers of cation channels, inhibited the 24-epicastasterone-induced cation channel activities. In Arabidopsis thaliana plants constitutively expressing aequorin, exogenous 24-epibrassonolide, 28-homobrassionolide and 24-epicastasterone induced a transient elevation of the cytosolic free Ca2+, which was inhibited by Gd3+ and mediated by Ca2+ influx from the bathing solution. In Ca2+-aequorin tests, 10 ?M of exogenous {BRs} was the minimal concentration at which statistically significant changes of the cytosolic Ca2+ were observed. In conclusion, the obtained results suggest that the plasma membrane of root cells contains the brassinosteroid-activated cation-permeable channels, which can probably be involved in rapid regulation of the K+ homeostasis and Ca2+ signalling

Water Ski Injuries and Chronic Pain in Collegiate Athletes

This study examined the rate of injuries and chronic pain in collegiate water-ski athletes as a preliminary study. We also compared the mechanics and cause of injuries by the level of water-skiing experiences. A total number of 96 collegiate water-ski athletes, aged 21.4 +/- 2.23 years, participated in the study. An off-line questionnaire was distributed at the collegiate tournaments in the United States. The questionnaire consisted of 20 questions, including demographic information, body region and type of injuries, mechanics and cause of injuries, chronic pain and pain management. A Chi-squared test was used to examine the differences in injury rates by sex and the level of experiences (beginner: <5 years, intermediate: 5-10 years, advanced: <10 years). The significance level was set at <= 0.05. A total of 336 water skiing-related injuries were observed from 96 participants. The ankle/feet, knee, and head/neck regions were the most common body regions injured, representing 26.5, 16.7, and 15.8%, respectively. Female athletes were more likely to have nerve injuries than male athletes (p = 0.039). The intermediate athletes were more likely to have trunk (p = 0.047) and upper extremity (p = 0.042) injuries than beginner athletes, and the beginner athletes had less joint/ligament (p = 0.001) and bone injury (p = 0.010) compared to the advanced athletes. Torsion/twisting (32.8%) and deceleration (26.9%) were the most common mechanism of injury. Beginner athletes experienced injuries more due to insufficient skill (p = 0.03), while the advanced athletes were likely to have more injuries by the loss of control (p = 0.01). Collegiate athletes had higher rates of chronic pain in the trunk (42.7%) and skeletal muscle (43.8%), and they participated in stretching/exercise (40.8%) and massage/form rolling (29.6%) to manage their chronic pain. The present study revealed that injury rates in males and females were 49.7% and 50.2%, respectively. Female athletes were more likely to have a nerve injury than male athletes. The mechanics and cause of injuries were different by the level of experiences where different training approaches may be required to minimize the injuries. Additionally, the strength and conditioning program that is systematically designed for core strength is needed to eliminate chronic trunk pain in collegiate water-skiing athletes

Water Ski Injuries and Chronic Pain in Collegiate Athletes

This study examined the rate of injuries and chronic pain in collegiate water-ski athletes as a preliminary study. We also compared the mechanics and cause of injuries by the level of water-skiing experiences. A total number of 96 collegiate water-ski athletes, aged 21.4 ± 2.23 years, participated in the study. An off-line questionnaire was distributed at the collegiate tournaments in the United States. The questionnaire consisted of 20 questions, including demographic information, body region and type of injuries, mechanics and cause of injuries, chronic pain and pain management. A Chi-squared test was used to examine the differences in injury rates by sex and the level of experiences (beginner: &lt;5 years, intermediate: 5–10 years, advanced: &lt;10 years). The significance level was set at ≤0.05. A total of 336 water skiing-related injuries were observed from 96 participants. The ankle/feet, knee, and head/neck regions were the most common body regions injured, representing 26.5, 16.7, and 15.8%, respectively. Female athletes were more likely to have nerve injuries than male athletes (p = 0.039). The intermediate athletes were more likely to have trunk (p = 0.047) and upper extremity (p = 0.042) injuries than beginner athletes, and the beginner athletes had less joint/ligament (p = 0.001) and bone injury (p = 0.010) compared to the advanced athletes. Torsion/twisting (32.8%) and deceleration (26.9%) were the most common mechanism of injury. Beginner athletes experienced injuries more due to insufficient skill (p = 0.03), while the advanced athletes were likely to have more injuries by the loss of control (p = 0.01). Collegiate athletes had higher rates of chronic pain in the trunk (42.7%) and skeletal muscle (43.8%), and they participated in stretching/exercise (40.8%) and massage/form rolling (29.6%) to manage their chronic pain. The present study revealed that injury rates in males and females were 49.7% and 50.2%, respectively. Female athletes were more likely to have a nerve injury than male athletes. The mechanics and cause of injuries were different by the level of experiences where different training approaches may be required to minimize the injuries. Additionally, the strength and conditioning program that is systematically designed for core strength is needed to eliminate chronic trunk pain in collegiate water-skiing athletes