40 research outputs found
Autophagy is suppressed by low temperatures and is dispensable for cold acclimation in Arabidopsis
No full textCitation: Akito Sato, Sena Inayoshi, Kohei Kitawaki, Ryota Mihara, Kosei Yoneda, Yasuko Ito‐Inaba, Takehito Inaba, Autophagy is suppressed by low temperatures and is dispensable for cold acclimation in Arabidopsis, Physiologia Plantarum, 176(4), 2024-07, https://doi.org/10.1111/ppl.1440
Small angle neutron scattering studies of magnetic recording media
No full textIn the beginning of the twenty-first century, educational and commercial institutions have driven the demand for cheap and efficient data storage. The storage medium known as magnetic recording media has remained the mainstay for most computer systems due to its large storage capacity per dollar. With the recording media's ever-increasing storage density has come reductions in the magnetic grain size per bit. At the recording bit's density threshold, the magnetic grains become more susceptible to thermal activation, which can render the storage medium unusable. An accurate characterisation of the recording layer's sub-granular structure is essential for understanding the magnetic and thermal mechanisms of high-density recording media. Small-Angle Neutron Scattering (SANS) studies have been performed to investigate the magnetic and physical properties of longitudinal and perpendicular recording grains.
The SANS studies of longitudinal magnetic recording media have probed the recording layer's magnetic grain size at a sub-nanometer resolution. In conjunction with these studies, SQUID magnetometry was used to characterise the recording grain's bulk magnetism. Measurements showed that the recording grain was composed of a ferromagnetic hard core (Co-enriched) and a weakly magnetic shell (Cr-enriched). These results provided important information on the grain's magnetic anisotropy, which determines the recording media's magnetic stability. The polarised SANS studies were used to characterise the recording layer's physical granular structure. It was shown that the physical grain size was comparable to its magnetic counterpart. These physical measurements provided insight into the recording grain's chemical composition.
The magnetic properties of perpendicular magnetic recording media were studied using SANS and VSM measurements. The neutron scattering studies revealed that the recording grain was composed of a hard ferromagnetic centre enriched with cobalt. The VSM studies showed that the magnetic recording grains exhibited a large perpendicular magnetic anisotropy. These combined studies provided information on the recording grain's ferromagnetic composition and magnetic stability. The polarised SANS measurements showed the physical grain size to be slightly smaller than its magnetic counterpart. This size difference was attributed to the non-magnetic grain boundary composed of SiO2. The boundary thickness determined the degree of inter-granular exchange coupling. Further polarised studies investigated the recording layers switching behaviour, which revealed more information on the grain's magnetic stability
Ubiquitin–Proteasome-Dependent Regulation of Bidirectional Communication between Plastids and the Nucleus
No full textUbiquitin–Proteasome-Dependent Regulation of Bidirectional Communication between Plastids and the Nucleus
No full textInvestigating Localization of Chimeric Transporter Proteins within Chloroplasts of Arabidopsis thaliana
No full textHigh-Throughput Screening Identification of Chemical Compounds That Affect Cold-Regulated Gene Expression in Arabidopsis thaliana Using an Excised Single Leaf
No full textThe identification of chemical compounds that affect intracellular processes has greatly contributed to the understanding of developmental regulation in plants. In this protocol, we describe a method for identifying chemical compounds that affect cold-regulated gene expression in Arabidopsis thaliana. Specifically, we generated Arabidopsis plants harboring a COLD-REGULATED 15A (COR15A) promoter::luciferase (COR15Apro::LUC) construct and grew them in a submerged liquid culture. Using a single true leaf excised from COR15Apro::LUC plants and 96-well culture plates, we performed high-throughput screening of chemical compounds that inhibit cold-induction of COR15Apro::LUC. Luciferase activity was detected using a microplate reader and a chemiluminescence imaging device. This protocol can be easily used for the identification of chemical compounds that regulate other processes, being versatile with respect to equipment
Specific and efficient targeting of cyanobacterial bicarbonate transporters to the inner envelope membrane of chloroplasts in Arabidopsis
No full textInstallation of cyanobacterial bicarbonate transporters to the inner envelope membrane (IEM) of chloroplasts in C3 plants has been thought to improve photosynthetic performance. However, the method to deliver cyanobacterial bicarbonate transporters to the chloroplast IEM remains to be established. In this study, we provide evidence that the cyanobacterial bicarbonate transporters, BicA and SbtA, can be specifically installed into the chloroplast IEM using the chloroplast IEM targeting signal in conjunction with the transit peptide. We fused the transit peptide and the mature portion of Cor413im1, whose targeting mechanism to the IEM has been characterized in detail, to either BicA or SbtA isolated from Synechocystis sp. PCC6803. Among the seven chimeric constructs tested, we confirmed that four chimeric bicarbonate transporters, designated as BicAI, BicAII, SbtAII, and SbtAIII, were expressed in Arabidopsis. Furthermore, these chimeric transporters were specifically targeted to the chloroplast IEM. They were also resistant to alkaline extraction but can be solubilized by Triton X-100, indicating that they are integral membrane proteins in the chloroplast IEM. One of the transporters, BicA, could reside in the chloroplast IEM even after removal of the IEM targeting signal. Taken together, our results indicate that the addition of IEM targeting signal, as well as the transit peptide, to bicarbonate transporters allows us to efficiently target nuclear-encoded chimeric bicarbonate transporters to the chloroplast IEM
Production of viable seeds from the seedling lethal mutant ppi2-2 lacking the atToc159 chloroplast protein import receptor using plastic containers, and characterization of the homozygous mutant progeny
No full textBiogenesis of chloroplasts is essential for plant growth and development. A number of homozygous mutants lacking a chloroplast protein exhibit an albino phenotype. In general, it is challenging to grow albino Arabidopsis plants on soil until they set seeds. Homozygous albino mutants are usually obtained as progenies of heterozygous parents. Here, we describe a method of recovering seeds from the seedling lethal Arabidopsis mutant ppi2-2, which lacks the atToc159 protein import receptor at the outer envelope membrane of chloroplast. Using plastic containers, we were able to grow homozygous ppi2-2 plants until these set seed. Although the germination rate of the harvested seeds was relatively low, it was still sufficient to allow us to further analyze the ppi2-2 progeny. Using ppi2-2 homozygous seeds, we were able to analyze the role of plastid protein import in the light-regulated induction of nuclear genes. We propose that this method be applied to other seedling lethal Arabidopsis mutants to obtain homozygous seeds, helping us further investigate the roles of plastid proteins in plant growth and development
Energetic Manipulation of Chloroplast Protein Import and the Use of Chemical Cross-Linkers to Map Protein–Protein Interactions
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