Abscisic acid inhibits hypocotyl elongation acting on gibberellins, DELLA proteins and auxin.

Hypocotyl elongation of <i>Arabidopsis</i> seedlings is influenced by light and numerous growth factors. Light induces inhibition of hypocotyl elongation (photomorphogenesis), whereas in the dark hypocotyl elongation is promoted (skotomorphogenesis). Abscisic acid (ABA) plays a major role in inhibition of hypocotyl elongation, but the molecular mechanism remains unclear. We investigated the effect of ABA during photo- and skotomorphogenesis, making use of appropriate mutants, and we show that ABA negatively controls hypocotyl elongation acting on gibberellin (GA) metabolic genes, increasing the amount of the DELLA proteins GAI and RGA, thus affecting GA signalling, and (ultimately) repressing auxin biosynthetic genes

Genome-wide RNA-seq analysis indicates that the DAG1 transcription factor promotes hypocotyl elongation acting on ABA, ethylene and auxin signaling.

Hypocotyl elongation is influenced by light and hormones, but the molecular mechanisms underlying this process are not yet fully elucidated. We had previously suggested that the Arabidopsis DOF transcription factor DAG1 may be a negative component of the mechanism of light-mediated inhibition of hypocotyl elongation, as light-grown dag1 knock-out mutant seedlings show significant shorter hypocotyls than the wild type. By using high-throughput RNA-seq, we compared the transcriptome profile of dag1 and wild type hypocotyls and seedlings. We identified more than 250 genes differentially expressed in dag1 hypocotyls, and their analysis suggests that DAG1 is involved in the promotion of hypocotyl elongation through the control of ABA, ethylene and auxin signaling. Consistently, ChIP-qPCR results show that DAG1 directly binds to the promoters of WRKY18 encoding a transcription factor involved in ABA signaling, of the ethylene- induced gene ETHYLENE RESPONSE FACTOR (ERF2), and of the SMALL AUXIN UP RNA 67 (SAUR67), an auxin-responding gene encoding a protein promoting hypocotyl cell expansion

Receptor and metabolic insights on the ability of caffeine to prevent alcohol-induced stimulation of mesolimbic dopamine transmission

The consumption of alcohol and caffeine affects the lives of billions of individuals worldwide. Although recent evidence indicates that caffeine impairs the reinforcing properties of alcohol, a characterization of its effects on alcohol-stimulated mesolimbic dopamine (DA) function was lacking. Acting as the pro-drug of salsolinol, alcohol excites DA neurons in the posterior ventral tegmental area (pVTA) and increases DA release in the nucleus accumbens shell (AcbSh). Here we show that caffeine, via antagonistic activity on A2A adenosine receptors (A2AR), prevents alcohol-dependent activation of mesolimbic DA function as assessed, in-vivo, by brain microdialysis of AcbSh DA and, in-vitro, by electrophysiological recordings of pVTA DA neuronal firing. Accordingly, while the A1R antagonist DPCPX fails to prevent the effects of alcohol on DA function, both caffeine and the A2AR antagonist SCH 58261 prevent alcohol-dependent pVTA generation of salsolinol and increase in AcbSh DA in-vivo, as well as alcohol-dependent excitation of pVTA DA neurons in-vitro. However, caffeine also prevents direct salsolinol- and morphine-stimulated DA function, suggesting that it can exert these inhibitory effects also independently from affecting alcohol-induced salsolinol formation or bioavailability. Finally, untargeted metabolomics of the pVTA showcases that caffeine antagonizes alcohol-mediated effects on molecules (e.g. phosphatidylcholines, fatty amides, carnitines) involved in lipid signaling and energy metabolism, which could represent an additional salsolinol-independent mechanism of caffeine in impairing alcohol-mediated stimulation of mesolimbic DA transmission. In conclusion, the outcomes of this study strengthen the potential of caffeine, as well as of A2AR antagonists, for future development of preventive/therapeutic strategies for alcohol use disorder

Social and Behavioral Rhythms is Related to the Perception of Quality of Life in Old Adults

Introduction: The purpose is to verify in old adults if social and behavioral rhythms (SBRs) are correlated with a positive perception of the quality of life (QoL). Social and behavioral rhythms and related circadian biorhythms are known as central points in the pathophysiology of bipolar disorders. A secondary aim is to see if a similar relationship can be found in Major Depressive Disorder (MDD) in old adults. Sample: 141 people aged ≥65 years (58.9% Female). Methods: Each subject was evaluated using the Social and Behavioral Rhythms Scale (in which higher scores show more dysfunctional SRBs); SF-12 for QoL and a screening tool for depressive symptoms. They underwent a medical evaluation and blood level assays including cholesterol and triglycerides. The medical diagnoses including MDD were taken into account. Results: The Social and Behavioral Rhythms Scale score correlated inversely with SF-12 score (p<0.001) and positively with PHQ9 (p<0.0001). People with MDD had a higher score on social rhythms than controls without (p<0.01). The study highlighted, for the first time, that social and behavioral rhythms have a role in old adults living in the community. Conclusion: Further longitudinal studies with a sufficient number of individuals will be required to confirm these data and clarify causal links of the association

Moderate exercise improves cognitive function in healthy elderly people: Results of a randomized controlled trial

BACKGROUND: Physical activity in the elderly is recommended by international guidelines to protect against cognitive decline and functional impairment. OBJECTIVE: This Randomized Controlled Trial (RCT) was set up to verify whether medium-intensity physical activity in elderly people living in the community is effective in improving cognitive performance. DESIGN: RCT with parallel and balanced large groups. SETTING: Academic university hospital and Olympic gyms. SUBJECTS: People aged 65 years old and older of both genders living at home holding a medical certificate for suitability in non-competitive physical activity. METHODS: Participants were randomized to a 12-week, 3 sessions per week moderate physical activity program or to a control condition focused on cultural and recreational activities in groups of the same size and timing as the active intervention group. The active phase integrated a mixture of aerobic and anaerobic exercises, including drills of “life movements”, strength and balance. The primary outcome was: any change in Addenbrooke's Cognitive Examination Revised (ACE-R) and its subscales. RESULTS: At the end of the trial, 52 people completed the active intervention, and 53 people completed the control condition. People in the active intervention improved on the ACE-R (ANOVA: F(1;102)=4.32, p=0.040), and also showed better performances on the memory (F(1;102)=5.40 p=0.022) and visual-space skills subscales of the ACE-R (F(1;102)=4.09 p=0.046). CONCLUSION: A moderate-intensity exercise administered for a relatively short period of 12 weeks is capable of improving cognitive performance in a sample of elderly people who live independently in their homes. Clinical Trials Registration No: NCT0385811