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

Reconstruction of the P2X2 Receptor Reveals a Vase-Shaped Structure with Lateral Tunnels above the Membrane

SummaryIn response to the intercellular messenger ATP, P2X receptors transfer various sensory information, including pain. Here we have reconstructed the structure of the P2X2 receptor at 15 Å resolution from more than 90,000 particle images, taken with a cryo-electron microscope equipped with a helium-cooled stage. This three-dimensional depiction, presumably in a closed state, revealed an elongated vase-shaped structure 202 Å in height and 160 Å in major diameter. The extracellular and transmembrane domains present a two-layered structure, in which a sparse outer layer surrounds a pore-forming inner density. The decreased diameter of a putative ion-conducting pathway at the middle of the membrane was considered to be the narrowest part of the pore, which has been predicted from electrophysiological studies. The sparse, extended structure of the P2X2 receptor indicates a loose assembly of subunits, which could be a basis for the activation-dependent pore dilation of P2X receptors

Mechanical loss of a multilayer tantala/silica coating on a sapphire disk at cryogenic temperatures: toward the KAGRA gravitational wave detector

We report the results of a new experimental setup to measure the mechanical loss of coating layers on a thin sapphire disk at cryogenic temperatures. Some of the authors previously reported that there was no temperature dependence of the mechanical loss from a multilayer tantala/silica coating on a sapphire disk, both before and after heat treatment, although some reports indicate that Ta<sub>2</sub>O<sub>5</sub> and SiO<sub>2</sub> layers annealed at 600 °C have loss peaks near 20 K. Since KAGRA—the Japanese gravitational-wave detector, currently under construction—will be operated at 20 K and have coated sapphire mirrors, it is very important to clarify the mechanical loss behavior of tantala/silica coatings around this temperature. We carefully investigate a tantala/silica-coated sapphire disk with the new setup, anneal the disk, and then investigate the annealed disk. We find that there is no distinct loss peak both before and after annealing under particular conditions. The mechanical loss for the unannealed disk at 20 K is about 5×10<sup>−4</sup>, as previously reported, while that for the annealed disk is approximately 6.4×10<sup>−4</sup>

Sapphire mirror for the KAGRA gravitational wave detector

KAGRA, the Japanese interferometric gravitational wave detector currently under construction, will employ sapphire test masses for its cryogenic operation. Sapphire has an advantage in its higher thermal conductivity near the operating temperature 20 K compared to fused silica used in other gravitational wave detectors, but there are some uncertain properties for the application such as hardness, optical absorption, and birefringence. We introduce an optical design of the test masses and our recent R&D results to address the above properties. Test polish of sapphire substrate has especially proven that specifications on the surface are sufficiently met. Recent measurements of absorption and inhomogeneity of the refractive index of the sapphire substrate indicate that the other properties are also acceptable to use sapphire crystal as test masses

Characteristics and behavior of dissolved organic matter in the Kumaki River, Noto Peninsula, Japan

Dissolved organic matter (DOM) in river water was studied to understand the transport behavior of DOM in a small watershed with forest and paddy fields. Field experiments were conducted under normal flow conditions in the Kumaki River, which is located in the central part of the Noto Peninsula in Japan, during the period 2009-2010. The concentrations and structural properties of fulvic acid-like components, which are the major components of DOM, were determined using three-dimensional excitation-emission matrix spectroscopy and high-performance size-exclusion chromatography. The relative fluorescence intensity for fulvic acid-like components at an excitation wavelength of 305-335 nm and an emission wavelength of 425-440 nm increased from the upper forest area to the lower paddy field area and increased seasonally in this river system in the following order: winter, autumn, spring, summer. Fulvic acid-like components with a higher molecular weight were observed in the summer samples. These results suggest that higher precipitation and agricultural activity in the summer season increase the amount of fulvic acid-like components with higher molecular weight that are transported from the watershed into the river. © 2014 The Japanese Society of Limnology

RNA-binding protein ptbp1 regulates alternative splicing and transcriptome in spermatogonia and maintains spermatogenesis in concert with nanos3

Manami SENOO, Hiroshi HOZOJI, Yu ISHIKAWA-YAMAUCHI, Takashi TAKIJIRI, Sho OHTA, Tomoyo UKAI, Mio KABATA, Takuya YAMAMOTO, Yasuhiro YAMADA, Masahito IKAWA, Manabu OZAWA, RNA-binding protein Ptbp1 regulates alternative splicing and transcriptome in spermatogonia and maintains spermatogenesis in concert with Nanos3, Journal of Reproduction and Development, 2020, Volume 66, Issue 5, Pages 459-467, Released October 13, 2020, [Advance publication] Released July 06, 2020, Online ISSN 1348-4400, Print ISSN 0916-8818, https://doi.org/10.1262/jrd.2020-060, https://www.jstage.jst.go.jp/article/jrd/66/5/66_2020-060/_article/-char/e

Liposomal amphotericin B for a case of intractable cryptococcal meningoencephalitis and immune reconstitution syndrome

We examined the efficacy of liposomal amphotericin B (L-AMB) for intractable cryptococcal meningoencephalitis in a patient with acquired immunodeficiency syndrome (AIDS) and the presence of immune reconstitution syndrome (IRS) caused by the treatment. A 34-year-old patient presented with meningitis. Cryptococcal organisms were detected microscopically in the cerebrospinal fluid (CSF) with Indian ink staining, and were then cultured from the CSF. Initial treatment with amphotericin B and flucytosine (5-FC) or voriconazole and/or fluconazole failed to eradicate cryptococcal organisms from the CSF. Secondary treatment with L-AMB and 5-FC following seven months of antiretroviral therapy was successful. Simultaneously, treatment with L-AMB caused severe brain edema likely due to IRS. There were large differences in immune function improvement and liposomalization of the fungicide between the initial and secondary treatments. In conclusion, differences in immune status should be considered when administering L-AMB, in order to prevent IRS-related complications

Convalescence of atypical reversible posterior leukoencephalopathy syndrome in human immunodeficiency virus infection

Reversible Posterior Leukoencephalopathy Syndrome (RPLS) is an uncommon neurological disorder which shows the diffuse edema in white matter of occipital lobe of brain. In this report, we describe a RPLS case with Human Immunodeficiency Virus (HIV) infection, whose lesion was improved with Highly Active Antiretroviral Therapy (HAART). A HIV-infected man, who was diagnosed as a mental deterioration with Central Pontine Myelinolysis (CPM) appearing high intensity pontine lesion in brain Magnetic Resonance Imaging (MRI), improved with HAART. No episode of hyponatremia or hypertension was observed in his clinical course. Evaluation of apparent diffusion coefficient (ADC) mapping in diffusion weight imaging (DWI) was performed in brain MRI at the onset and four months after commencement of HAART. ADC mapping enabled to interpret the pontine lesion as RPLS. HAART improved the mental deterioration within two weeks and the elevated ADC value at the onset was normalized at four-month clinical course