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Identification of plb1 mutation that extends longevity via activating Sty1 MAPK in Schizosaccharomyces pombe
To understand the lifespan of higher organisms, including humans, it is important to understand lifespan at the cellular level as a prerequisite. So, fission yeast is a good model organism for the study of lifespan. To identify the novel factors involved in longevity, we are conducting a large-scale screening of long-lived mutant strains that extend chronological lifespan (cell survival in the stationary phase) using fission yeast. One of the newly acquired long-lived mutant strains (No.98 mutant) was selected for analysis and found that the long-lived phenotype was due to a missense mutation (92Phe → Ile) in the plb1^+ gene. plb1^+ gene in fission yeast is a nonessential gene encoding a homolog of phospholipase B, but its functions under normal growth conditions, as well as phospholipase B activity, remain unresolved. Our analysis of the No.98 mutant revealed that the plb1 mutation reduces the integrity of the cellular membrane and cell wall and activates Sty1 via phosphorylation
Developing Polymeric Nanoparticles for Controlled Drug Delivery in Anti-inflammatory Therapies
Investigation of small-fraction molecular impurities in high-pressure helium plasmas using optical plasma diagnostic methods
In high-pressure plasmas using gases diluted via a rare gas, small-fraction impurities in the discharge space significantly impact the basic plasma parameters and excited-species generation processes. This study investigated the behaviors of molecular impurities in a dielectric barrier discharge (DBD) generated in a flow of high-purity He gas using optical plasma diagnostic methods. The optical emission spectra obtained under various discharge conditions (pressure, flow rate, and voltage frequency) indicated that the major impurity species in the He DBD was the H₂O molecule, and the DBD decomposed the H₂O before reaching the measurement spot. To quantitatively analyze the H₂O fraction, time-resolved laser absorption spectroscopy was performed to measure the exponential decay time of He metastable (Hem) atoms in the He-DBD. The H₂O fraction in the He gas flow was derived from the dependence of Hem lifetime decay on the voltage frequency. In addition, a model was proposed to estimate the H₂O fraction under various He pressure and flow rate conditions from reference data. The procedures to perform optical plasma diagnostics and evaluate the fraction and behavior of H₂O impurities are expected to facilitate a better understanding and control of high-pressure plasmas
Continuous-Flow PET-RAFT Polymerization in a Packed-Bed Reactor with Porphyrin-Immobilized Silica Particles
Photoinduced electron/energy transfer-reversible addition–fragmentation chain transfer (PET-RAFT) polymerization enables the production of well-controlled synthetic polymers under mild conditions by using visible-light energy. Although flow reactors are suitable for photoreactions in terms of light penetration, contamination of photocatalysts occurs in a homogeneous system and necessitates product purification. Immobilizing the photocatalysts onto supports can eliminate the need for this purification step and enhance the potential for industrial applications of PET-RAFT polymerization. Herein, we report the development of a packed-bed flow photoreactor wherein a photocatalyst for PET-RAFT polymerization, zinc tetraphenylporphyrin, was immobilized onto packed silica particles. Continuous PET-RAFT polymerization of a model monomer (N,N-dimethylacrylamide) was achieved without leakage of the porphyrin molecules. The effects of various reaction conditions, such as the residence time, catalyst density, and target molecular weight, on the polymerization reaction were evaluated. This work contributes to the realization of a facile and practical manufacturing process for highly valuable synthetic polymers