Actin isovariant ACT7 controls root meristem development in Arabidopsis through modulating auxin and ethylene responses.

The meristem is the most functionally dynamic part in a plant. The shaping of the meristem requires constant cell division and elongation, which are influenced by hormones and the cytoskeletal component, actin. Although the roles of hormones in modulating meristem development have been extensively studied, the role of actin in this process is still elusive. Using the single and double mutants of the vegetative class actin, we demonstrate that actin isovariant ACT7 plays an important role in root meristem development. In the absence of ACT7, but not ACT8 and ACT2, depolymerization of actin was observed. Consistently, the act7 mutant showed reduced cell division, cell elongation, and meristem length. Intracellular distribution and trafficking of auxin transport proteins in the actin mutants revealed that ACT7 specifically functions in the root meristem to facilitate the trafficking of auxin efflux carriers PIN1 and PIN2, and consequently the transport of auxin. Compared with act7, the act7act8 double mutant exhibited slightly enhanced phenotypic response and altered intracellular trafficking. The altered distribution of auxin in act7 and act7act8 affects the response of the roots to ethylene, but not to cytokinin. Collectively, our results suggest that ACT7-dependent auxin-ethylene response plays a key role in controlling Arabidopsis root meristem development.

Plasma Membrane Aquaporin Members PIPs Act in Concert to Regulate Cold Acclimation and Freezing Tolerance Responses in Arabidopsis thaliana.

Aquaporins play a major role in plant water uptake at both optimal and environmentally stressed conditions. However, the functional specificity of aquaporins under cold remains obscure. To get a better insight to the role of aquaporins in cold acclimation and freezing tolerance, we took an integrated approach of physiology, transcript profiling and cell biology in Arabidopsis thaliana. Cold acclimation resulted in specific upregulation of PIP1;4 and PIP2;5 aquaporin (plasma membrane intrinsic proteins) expression, and immunoblotting analysis confirmed the increase in amount of PIP2;5 protein and total amount of PIPs during cold acclimation, suggesting that PIP2;5 plays a major role in tackling the cold milieu. Although single mutants of pip1;4 and pip2;5 or their double mutant showed no phenotypic changes in freezing tolerance, they were more sensitive in root elongation and cell survival response under freezing stress conditions compared with the wild type. Consistently, a single mutation in either PIP1;4 or PIP2;5 altered the expression of a number of aquaporins both at the transcriptional and translational levels. Collectively, our results suggest that aquaporin members including PIP1;4 and PIP2;5 function in concert to regulate cold acclimation and freezing tolerance responses.

The right way to kiss: directionality bias in head-turning during kissing.

Humans have a bias for turning to the right in a number of settings. Here we document a bias in head-turning to the right in adult humans, as tested in the act of kissing. We investigated head-turning bias in both kiss initiators and kiss recipients for lip kissing, and took into consideration differences due to sex and handedness, in 48 Bangladeshi heterosexual married couples. We report a significant male bias in the initiation of kissing and a significant bias in head-turning to the right in both kiss initiators and kiss recipients, with a tendency among kiss recipients to match their partners' head-turning direction. These interesting outcomes are explained by the influences of societal learning or cultural norms and the potential neurophysiological underpinnings which together offer novel insights about the mechanisms underlying behavioral laterality in humans.

Early Menopause in Type 2 Diabetes - A Study from a South Indian Tertiary Care Centre.

INTRODUCTION: Menopause marks the end of ovarian function and it is called 'early' or 'premature' if it occurs before 45 years. Very little is known about the menopause transition in Diabetic women. Metabolic disorders like diabetes will accelerate the reproductive ageing and determine premature ovarian failure by various mechanisms. Early menopause along with diabetes has a synergistic effect over the incidence of cardiovascular diseases and other illnesses. There is no data regarding menopausal age in Indian population. Hence, present study was aimed at understanding the age of menopause in diabetic Indian women. MATERIALS AND METHODS: This study was carried out at a tertiary care, teaching hospital in Southern India. Post-menopausal women who attended the Department of Medicine during August 2013 to August 2014, were included in the study. Six hundred patients were recruited by a systematic random sampling, 300 diabetic and 300 non-diabetic after obtaining their consents. They were all non-smokers, took mixed diet and other somatometric variables were similar in both the groups. RESULTS: Average age of menopause among diabetic women was 44.65 years which is much earlier than the menopause in non-diabetic women (48.2 years). Out of the 600 women, 212 women had an early menopause (<45 yrs.). Among them, 54 were non-diabetic and 158 were diabetic. Present study also revealed a higher BMI among the diabetics than the non-diabetic women. This may be due to the changes in body composition and increase in abdominal fat after menopause. This change is more in diabetics due to the disturbances in insulin sensitivity and glucose metabolism. CONCLUSION: The present study confirms that Type 2 Diabetes increases the risk of early menopause. The study reinforces the importance of early diagnosis and treatment of diabetes for a long term well being of a woman.