A deazariboflavin chromophore kinetically stabilizes reduced FAD state in a bifunctional cryptochrome

An animal-like cryptochrome derived from Chlamydomonas reinhardtii (CraCRY) is a bifunctional flavoenzyme harboring flavin adenine dinucleotide (FAD) as a photoreceptive/catalytic center and functions both in the regulation of gene transcription and the repair of UV-induced DNA lesions in a light-dependent manner, using different FAD redox states. To address how CraCRY stabilizes the physiologically relevant redox state of FAD, we investigated the thermodynamic and kinetic stability of the two-electron reduced anionic FAD state (FADH−) in CraCRY and related (6–4) photolyases. The thermodynamic stability of FADH− remained almost the same compared to that of all tested proteins. However, the kinetic stability of FADH− varied remarkably depending on the local structure of the secondary pocket, where an auxiliary chromophore, 8-hydroxy-7,8-didemethyl-5-deazariboflavin (8-HDF), can be accommodated. The observed effect of 8-HDF uptake on the enhancement of the kinetic stability of FADH− suggests an essential role of 8-HDF in the bifunctionality of CraCRY.Hosokawa Y., Morita H., Nakamura M., et al. A deazariboflavin chromophore kinetically stabilizes reduced FAD state in a bifunctional cryptochrome. Scientific Reports 13, 16682 (2023); https://doi.org/10.1038/s41598-023-43930-0

Cell competition is driven by Xrp1-mediated phosphorylation of eukaryotic initiation factor 2α

生体から不良細胞を除去する「細胞競合」の仕組みの一端を解明 --不良細胞は小胞体ストレス応答機構を使ってタンパク質合成量を低下させ除去される--. 京都大学プレスリリース. 2021-12-08.Cell competition is a context-dependent cell elimination via cell-cell interaction whereby unfit cells (‘losers’) are eliminated from the tissue when confronted with fitter cells (‘winners’). Despite extensive studies, the mechanism that drives loser’s death and its physiological triggers remained elusive. Here, through a genetic screen in Drosophila, we find that endoplasmic reticulum (ER) stress causes cell competition. Mechanistically, ER stress upregulates the bZIP transcription factor Xrp1, which promotes phosphorylation of the eukaryotic translation initiation factor eIF2α via the kinase PERK, leading to cell elimination. Surprisingly, our genetic data show that different cell competition triggers such as ribosomal protein mutations or RNA helicase Hel25E mutations converge on upregulation of Xrp1, which leads to phosphorylation of eIF2α and thus causes reduction in global protein synthesis and apoptosis when confronted with wild-type cells. These findings not only uncover a core pathway of cell competition but also open the way to understanding the physiological triggers of cell competition

Loss of α-Synuclein Does Not Affect Mitochondrial Bioenergetics in Rodent Neurons.

Increased α-synuclein (αsyn) and mitochondrial dysfunction play central roles in the pathogenesis of Parkinson's disease (PD), and lowering αsyn is under intensive investigation as a therapeutic strategy for PD. Increased αsyn levels disrupt mitochondria and impair respiration, while reduced αsyn protects against mitochondrial toxins, suggesting that interactions between αsyn and mitochondria influences the pathologic and physiologic functions of αsyn. However, we do not know if αsyn affects normal mitochondrial function or if lowering αsyn levels impacts bioenergetic function, especially at the nerve terminal where αsyn is enriched. To determine if αsyn is required for normal mitochondrial function in neurons, we comprehensively evaluated how lowering αsyn affects mitochondrial function. We found that αsyn knockout (KO) does not affect the respiration of cultured hippocampal neurons or cortical and dopaminergic synaptosomes, and that neither loss of αsyn nor all three (α, β and γ) syn isoforms decreased mitochondria-derived ATP levels at the synapse. Similarly, neither αsyn KO nor knockdown altered the capacity of synaptic mitochondria to meet the energy requirements of synaptic vesicle cycling or influenced the localization of mitochondria to dopamine (DA) synapses in vivo. Finally, αsyn KO did not affect overall energy metabolism in mice assessed with a Comprehensive Lab Animal Monitoring System. These studies suggest either that αsyn has little or no significant physiological effect on mitochondrial bioenergetic function, or that any such functions are fully compensated for when lost. These results implicate that αsyn levels can be reduced in neurons without impairing (or improving) mitochondrial bioenergetics or distribution

Irinotecan Hydrochloride (CPT-11) in Dialysis Patients with Gastrointestinal Cancer

We investigated changes in drug disposition and toxicities with CPT-11 in 15 dialysis patients with gastrointestinal cancers to clarify whether CPT-11 could be administered safely in such patients. For comparison, the same parameters were also investigated in 10 cancer patients not undergoing dialysis. Items investigated included (1) plasma concentrations of SN-38, SN-38G and CPT-11 at 0, 1, 12, 24, 36, 48 and 72h after administration, together with a comparison of mean AUC values for 3 dose levels of CPT-11 (50, 60 and 70mg/m2) in dialysis patients and controls;and (2) occurrence of adverse events. Several findings emerged from this study:(1) No significant difference was observed in the AUC for SN-38 or CPT-11 between the dialysis and control groups;(2) The AUC for SN-38G at each dose was significantly higher in dialysis patients;and (3) Grade 1-4 leucopenia was observed in 11 of the dialysis patients. One patient developed grade 4 leucopenia and died due to sepsis. Anorexia, diarrhea, nausea, alopecia and interstitial pneumonia occurred in 6 dialysis patients. We found changes in drug dispositions of CPT-11, SN-38 and SN-38G in dialysis patients, suggesting that hepatic excretion, especially that of SN-38G, was increased. No significant difference in occurrence of adverse events was observed between the 2 groups. This indicates that CPT-11 can be administered safely in patients on dialysis.</p

Eta-photoproduction in a gauge-invariant chiral unitary framework

We analyse photoproduction of eta mesons off the proton in a gauge-invariant chiral unitary framework. The interaction kernel for meson-baryon scattering is derived from the leading order chiral effective Lagrangian and iterated in a Bethe-Salpeter equation. The recent precise threshold data from the Crystal Ball at MAMI can be described rather well and the complex pole corresponding to the S11(1535) is extracted. An extension of the kernel is also discussed.Comment: Updated version to be published in Physics Letters

Assessing the Structural Characteristics of the Japanese Version of the Adult Social Care Outcomes Toolkit for Carers

As there are no standardized measures of Quality of Life (QoL) of informal carers impacted by use of long-term care (LTC) in Japan, the development or translation and cross-cultural adaptation of LTC outcomes measures for carers is needed for LTC research and evaluation. In this study, we assessed the validity and reliability of the factor structure and response system of the translated and cross-culturally adapted Japanese version of the Adult Social Care Outcomes Toolkit for Carer (J-ASCOTCarer). Participants were 872 informal family caregivers of adults with LTC services, living at home. Almost half (46 %) were aged between 50 and 59 years and 60 % took care of their mother . We used a combined factor analysis and item response theory approach. Model fit indices consideredwerefactor loading, path coefficients, root mean square error of approximation, standardized root mean square residual, and comparative fit index. This study confirmed the one factor structure ofthe original English version of the ASCOT-Carer. The values for the model fit indices indicated a good fit. The validity and reliability of the response system wereconfirmed. The J-ASCOT-Carer is a promising assessment instrument to measure QoL of Japanese caregivers of adultswith LTC

Pancreatic insulin release in vitamin C-deficient senescence marker protein-30/gluconolactonase knockout mice

We recently identified senescence marker protein-30 as the lactone-hydrolyzing enzyme gluconolactonase, which is involved in vitamin C biosynthesis. In this study, we investigated the effects of vitamin C on insulin secretion from pancreatic β-cells using senescence marker protein-30/gluconolactonase knockout mice. In intraperitoneal glucose tolerance tests, vitamin C-deficient senescence marker protein-30/gluconolactonase knockout mice demonstrated impaired glucose tolerance with significantly lower blood insulin levels at 30 and 120 min post-challenge than in wild type mice (p<0.01–0.05). In contrast, vitamin C-sufficient senescence marker protein-30/gluconolactonase knockout mice demonstrated significantly higher blood glucose and lower insulin only at the 30 min post-challenge time point (p<0.05). Senescence marker protein-30/gluconolactonase knockout mice showed enhanced insulin sensitivity regardless of vitamin C status. Static incubation of islets revealed that 20 mM glucose-stimulated insulin secretion and islet ATP production were significantly decreased at 60 min only in vitamin C-deficient SMP30/GNL knockout mice relative to wild type mice (p<0.05). These results indicate that the site of vitamin C action lies between glycolysis and mitochondrial oxidative phosphorylation, while SMP30 deficiency itself impairs the distal portion of insulin secretion pathway

Synthesis and Antimicrobial Evaluation of Side-Chain Derivatives based on Eurotiumide A

Side-chain derivatives of eurotiumide A, a dihydroisochroman-type natural product, have been synthesized and their antimicrobial activities described. Sixteen derivatives were synthesized from a key intermediate of the total synthesis of eurotiumide A, and their antimicrobial activities against two Gram-positive bacteria, methicillin-susceptible and methicillin-resistant Staphylococcus aureus (MSSA and MRSA), and a Gram-negative bacterium, Porphyromonas gingivalis, were evaluated. The results showed that derivatives having an iodine atom on their aromatic ring instead of the prenyl moiety displayed better antimicrobial activity than eurotiumide A against MSSA and P. gingivalis. Moreover, we discovered that a derivative with an isopentyl side chain, which is a hydrogenated product of eurotiumide A, is the strongest antimicrobial agent against all three strains, including MRSA

Effects of a Worksite Stress Management Training Program with Six Short-hour Sessions: A Controlled Trial among Japanese Employees

Objectives: The purpose of this study was to evaluate the effectiveness of a multi-component worksite stress management training (SMT) program among employees belong to Japanese steel company. Methods: Five workplaces were assigned to an intervention group and two workplaces to a control group. SMT with monthly 30-min sessions were provided to the intervention group for 6 mo. Intention-to-treat analyses were conducted among respondents of the intervention (n=96) and control groups (n=53). Results: Significant favorable intervention effects were found on knowledge (p0.05). However, in per-protocol analyses of those who attended all sessions, significant favorable effects were observed on psychological distress and job performance, as well as knowledge and professional efficacy (p<0.05). In addition, subgroup analyses revealed that those with initial low job control showed a favorable intervention effect only on knowledge (p<0.001), whereas those with initial high job control showed favorable intervention effects on knowledge (p<0.001), professional efficacy (p=0.023) and anxiety (p=0.033). Conclusions: The results suggest that the multi-component SMT program is effective at improving knowledge and professional efficacy, although job control appeared to moderate the effect of the program on professional efficacy. The program may also be effective at reducing psychological distress and increasing job performance, if participants complete all sessions

Cloning, expression analysis, and tissue distribution of esp-1/testisin, a membrane-type serine protease from the rat

Esp-1/testisin, a serine protease abundantly expressed in human and mouse testis, is presumed to play an important role in the process of spermatogenesis and fertilization. In this study, we cloned an esp-1/testisin cDNA from rats, and analyzed its expression and tissue distribution. The isolated cDNA consisted of 1099 nucleotides with a single open reading frame encoding 328 amino acids and an expected molecular mass of 36.6 kDa. The deduced amino acid sequence of rat Esp-1/Testisin had 89% and 62% identity with its murine and human counterparts, respectively, and appeared to be a trypsin-type serine protease with a hydrophobic region at the C-terminus. By quantitative real-time polymerase chain reaction analysis, rat esp-1/testisin mRNA was predominantly expressed in testis, as in human and mouse. However, its immunohistochemical distribution was predominantly in the elongated spermatids at steps 12 to 19, and not in the primary spermatocytes and round spermatids. This different distribution profile suggests that Esp-1/Testisin plays a role in species-specific proteolytic events during spermatogenesis and fertilization