The dwarf phenotype of the Arabidopsis acl5 mutant is suppressed by a mutation in an upstream ORF of a bHLH gene

Loss-of-function mutants of the Arabidopsis thaliana ACAULIS 5 (ACL5) gene, which encodes spermine synthase, exhibit a severe dwarf phenotype. To elucidate the ACL5-mediated regulatory pathways of stem internocle elongation, we isolated four suppressor of acaulis (sac) mutants that reverse the acl5 dwarf phenotype. Because these mutants do not rescue the dwarfism of known phytohormone-related mutants, the SAC genes appear to act specifically on the ACL5 pathways. We identify the gene responsible for the dominant sac51-d mutant, which almost completely suppresses the acl5 phenotype. sac51-d disrupts a short upstream open reading frame (uORF) of SAC51, which encodes a bHLH-type transcription factor. Our results indicate that premature termination of the uORF in sac51-d results in an increase in its own transcript level, probably as a result of an increased translation of the main ORF. We suggest a model in which ACL5 plays a role in the translational activation of SAC51, which may lead to the expression of a subset of genes required for stem elongation

Study on Wash-out of Asphalt Mixture Caused by Repeated Heating and Cooling Immersion Test

Stripping generates within the asphalt pavements due to continuous effect of moisture has been one of the concerns by the road authorities worldwide. Without a proper treatment, it could cause potholes and lower the bearing capacity of asphalt pavements. With regard to this, it is well known that the bipolar anti-stripping agent is effective to prevent the stripping due to its electrochemical bonding characteristics between aggregate and asphalt. Wash-out is a dynamic water action that could strip the asphalt mortar from pavement surfacing. Such distress spotted on many roads, whereby, granite aggregates are normally used as the main material in asphalt mixtures. In this study, the experimental work is focused on stripping phenomenon caused by multiple moisture conditioning cycles at 80 °C, and a newly developed evaluation protocol using a Repeated Heating and Cooling Immersion test is adopt-ed. The Wash-out, which is closely associated with stripping, is studied to evaluate the resistance of asphalt pavement against moisture damage. This study is a laboratory scale evaluation and the phenomenon in the field is not yet adequately considered. The repeated heating and cooling immersion procedure is an accelerated strip-ping conditioning without applying an external force. It is clarified that the resistance to the Wash-out of asphalt mixture is improved with the presence of the bi-polar anti-stripping agent, known as Tough Fix Hyper at the rate of 0.15% or more

Study on Wash-out of Asphalt Mixture Caused by Repeated Heating and Cooling Immersion Test

Stripping generates within the asphalt pavements due to continuous effect of moisture has been one of the concerns by the road authorities worldwide. Without a proper treatment, it could cause potholes and lower the bearing capacity of asphalt pavements. With regard to this, it is well known that the bipolar anti-stripping agent is effective to prevent the stripping due to its electrochemical bonding characteristics between aggregate and asphalt. Wash-out is a dynamic water action that could strip the asphalt mortar from pavement surfacing. Such distress spotted on many roads, whereby, granite aggregates are normally used as the main material in asphalt mixtures. In this study, the experimental work is focused on stripping phenomenon caused by multiple moisture conditioning cycles at 80 °C, and a newly developed evaluation protocol using a Repeated Heating and Cooling Immersion test is adopt-ed. The Wash-out, which is closely associated with stripping, is studied to evaluate the resistance of asphalt pavement against moisture damage. This study is a laboratory scale evaluation and the phenomenon in the field is not yet adequately considered. The repeated heating and cooling immersion procedure is an accelerated strip-ping conditioning without applying an external force. It is clarified that the resistance to the Wash-out of asphalt mixture is improved with the presence of the bi-polar anti-stripping agent, known as Tough Fix Hyper at the rate of 0.15% or more

Periodic super-radiance in Er:YSO crystal

We observed periodic optical pulses from an Er:YSO crystal during irradiating with an continuous-wave excitation laser. We refer to this new phenomenon as "periodic super-radiance". This periodicity can be understood qualitatively by a simple model, in which a cyclic process of a continuous supply of population inversion and a sudden burst of super-radiance is repeated. The excitation power dependences of peak interval and the pulse area can be interpreted with our simple model. In addition, the linewidth of super-radiance is much narrower than an inhomogeneous broadening in a crystal. This result suggests that only Er3+ ions in a specific environment are involved in super-radiance.Comment: 7 pages, 5 figure

Ubiquitin-Specific Peptidase 46 (Usp46) Regulates Mouse Immobile Behavior in the Tail Suspension Test through the GABAergic System

The tail suspension test (TST) is widely recognized as a useful experimental paradigm for assessing antidepressant activity and depression-like behavior. We have previously identified ubiquitin-specific peptidase 46 (Usp46) as a quantitative trait gene responsible for decreasing immobility time in the TST in mice. This Usp46 mutation has a 3-bp deletion coding for lysine in the open reading frame, and we indicated that Usp46 is implicated in the regulation of the GABAergic system. However, it is not known precisely how the immobile behavior is regulated by the GABAergic system. Therefore, in the present study, we examined whether the immobility time is influenced by drugs affecting the action mediated by GABAA receptor using both 3-bp deleted (the Usp46 mutant) and null Usp46 (Usp46 KO) mice. Nitrazepam, an agonist at the benzodiazepine-binding site of the GABAA receptor, which potentiates the action of GABA, produced a dose-dependent increase in TST immobility time in the Usp46 mutant mice without affecting general behaviors. The Usp46 KO mice exhibited short immobility times comparable to the Usp46 mutant mice, which was also increased by nitrazepam administration. The effects of nitrazepam in the Usp46 mutant and KO mice were antagonized by flumazenil. These results indicate that the 3-bp deleted Usp46 mutation causes a loss-of-function phenotype, and that the GABAA receptor might participate in the regulation of TST immobility time

Lowered sensitivity of bitter taste receptors to β-glucosides in bamboo lemurs: an instance of parallel and adaptive functional decline in TAS2R16?

竹食サル類の苦味感覚の進化を解明 --竹が先か苦味が先か--. 京都大学プレスリリース. 2021-04-16.Bitter taste facilitates the detection of potentially harmful substances and is perceived via bitter taste receptors (TAS2Rs) expressed on the tongue and oral cavity in vertebrates. In primates, TAS2R16 specifically recognizes β-glucosides, which are important in cyanogenic plants' use of cyanide as a feeding deterrent. In this study, we performed cell-based functional assays for investigating the sensitivity of TAS2R16 to β-glucosides in three species of bamboo lemurs (Prolemur simus, Hapalemur aureus and H. griseus), which primarily consume high-cyanide bamboo. TAS2R16 receptors from bamboo lemurs had lower sensitivity to β-glucosides, including cyanogenic glucosides, than that of the closely related ring-tailed lemur (Lemur catta). Ancestral reconstructions of TAS2R16 for the bamboo-lemur last common ancestor (LCA) and that of the Hapalemur LCA showed an intermediate sensitivity to β-glucosides between that of the ring-tailed lemurs and bamboo lemurs. Mutagenetic analyses revealed that P. simus and H. griseus had separate species-specific substitutions that led to reduced sensitivity. These results indicate that low sensitivity to β-glucosides at the cellular level-a potentially adaptive trait for feeding on cyanogenic bamboo-evolved independently after the Prolemur-Hapalemur split in each species