Search Results (39)

A drastic alteration in the potency or efficacy of bioactive compounds due to the addition of a single methyl group is known as the magic methyl effect. This effect has been demonstrated in O-methylated flavonoids, which show differences in physical and chemical properties from those of unmethylated flavonoids—O-methylation converts the hydrophilic hydroxy group into a hydrophobic methoxy group. However, differences in the physical and chemical properties between C-methylated and unmethylated flavonoids are smaller than those for O-methylated flavonoids. Therefore, predicting the magic methyl effect in C-methylated flavonoids is challenging. Eucalyptin and 8-desmethyleucalyptin are C-methylated flavonoids isolated from the leaves of plants, such as Eucalyptus sp. and Kalmia latifolia. These compounds contain 5-hydroxy-7,4′-dimethoxyflavone as the core skeleton. Eucalyptin has two C-methyl groups at the C-6 and C-8 positions, whereas 8-desmethyleucalyptin has one C-methyl group at the C-6 position. In this study, we synthesized eucalyptin and assessed its biological activities. The C-8 methyl group caused significant alterations in cytotoxic and antibiofilm activities. Herein, we report the magic methyl effects in eucalyptin, providing a basis for further chemical and biological studies on C-methylated flavonoids. Full article

Background: The relationship between hospitalization duration and physical function in patients with chronic kidney disease (CKD) has not been thoroughly investigated. This study aimed to determine whether assessment of physical function one week after hospitalization can predict the length of stay in patients with CKD. Methods: A retrospective study was conducted on hospitalized patients with CKD who underwent rehabilitation between March 2019 and March 2020. Physical function was evaluated using the Short Physical Performance Battery (SPPB), grip strength, and Barthel Index and analyzed alongside clinical data. Results: The mean age of the participants was 73.4 ± 11.9 years, with 92% having stage G4 or G5 CKD. Multivariate analysis revealed that the SPPB (β = −0.33, p < 0.01) at one week after admission was significantly associated with the length of hospital stay (R² = 0.11, p < 0.02). Notably, in the subgroup of patients who were transferred to other facilities, the SPPB alone showed a strong association with the length of stay (β = −0.66, p < 0.03, R² = 0.23, p < 0.05). Conclusions: The SPPB score in the early stages of hospitalization for patients with CKD was found to be a significant predictor of the length of stay, even after considering the eGFR and the Charlson Comorbidity Index. These findings may contribute to optimizing inpatient management and rehabilitation strategies for patients with CKD. Full article

Background/Objectives: BRAF mutations occur in 5–10% of metastatic colorectal cancer (mCRC) cases, but their implications for prognosis and optimal treatment remain unclear. Methods: This multicenter, prospective observational study analyzed 377 RAS wild-type cases from 511 patients across 32 centers, using PCR-based methods. Results: BRAF mutations were identified in 21% (79/377) of cases, predominantly V600E (89.9%) with a minority of non-V600E (10.1%). Microsatellite instability (MSI) testing revealed MSI-high in 11.3%, exclusively among V600E cases. V600E mutations were linked to right-sided tumors, poor differentiation, and elevated CA19-9 levels. Median survival was significantly lower in V600E cases compared to BRAF wild-type (12.4 vs. 37.5 months, HR 3.25, p < 0.001) and marginally lower non-V600E cases (12.4 vs. 34.7 months, HR 0.61, p = 0.057). Chemotherapy regimens (doublet vs. triplet) and targeted treatments (bevacizumab vs. anti-EGFR) showed no significant survival differences in V600E patients. Similarly, RAS/BRAF wild-type patients had comparable survival with bevacizumab versus anti-EGFR, even for left-sided tumors. Conclusions: These findings highlight distinct clinical and prognostic profiles for BRAF V600E and non-V600E mutations, while treatment choice appears to have limited impact on survival in these subgroups or RAS/BRAF wild-type cases. Full article

To achieve artificial photosynthesis, it is crucial to develop a catalytic system for CO₂ reduction using water as the electron source. However, photochemical CO₂ reduction by homogeneous molecular catalysts has predominantly been conducted in organic solvents. This study investigates the impact of water content on catalytic activity in photochemical CO₂ reduction in N,N-dimethylacetamide (DMA), using [Ru(bpy)₃]²⁺ (bpy: 2,2′-bipyridine) as a photosensitizer, 1-benzyl-1,4-dihydronicotinamide (BNAH) as an electron donor, and two ruthenium diimine carbonyl complexes, [Ru(bpy)₂(CO)₂]²⁺ and trans(Cl)-[Ru(Ac-5Bpy-NHMe)(CO)₂Cl₂] (5Bpy: 5′-amino-2,2′-bipyridine-5-carboxylic acid), as catalysts. Increasing water content significantly decreased CO and formic acid production. The similar rates of decrease for both catalysts suggest that water primarily affects the formation efficiency of free one-electron-reduced [Ru(bpy)₃]²⁺, rather than the intrinsic catalytic activity. The reduction in cage-escape efficiency with higher water content underscores the challenges in replacing organic solvents with water in photochemical CO₂ reduction. Full article

Melanin is produced by melanocytes to protect human skin from harmful ultraviolet radiation. During skin cell renewal, melanin and dead skin cells are disposed of. However, prolonged exposure to ultraviolet rays or aging can disturb this cycle, leading to skin hyperpigmentation due to melanin accumulation. Tyrosinase is a crucial enzyme involved in melanin biosynthesis. Although various compounds, including tyrosine inhibitors, that counteract melanin accumulation have been reported, some, such as hydroquinone, are toxic and can cause vitiligo. Meanwhile, the skin is the largest organ and the outermost layer of the immune system, containing a diverse range of bacteria that produce low-toxicity compounds. In the current study, we aim to identify metabolites produced by skin microbiota that inhibit tyrosinase. Specifically, mushroom tyrosinase served as the study model. Following commensal skin bacteria screening, Corynebacterium tuberculostearicum was found to inhibit tyrosinase activity. The active compound was cyclo(l-Pro-l-Tyr); commercially available cyclo(l-Pro-l-Tyr) also exhibited inhibitory activity. Docking simulations suggested that cyclo(l-Pro-l-Tyr) binds to the substrate-binding site of mushroom tyrosinase, obstructing the substrate pocket and preventing its activity. Hence, cyclo(l-Pro-l-Tyr) might have potential applications as a cosmetic agent and food additive. Full article

Iron porphyrins are known to provide CH₄ as an eight-electron reduction product of CO₂ in a photochemical reaction. However, there are still some aspects of the reaction mechanism that remain unclear. In this study, we synthesized iron porphyrin dimers and carried out the photochemical CO₂ reduction reactions in N,N-dimethylacetamide (DMA) containing a photosensitizer in the presence of 1,3-dimethyl-2-phenyl-2,3-dihydro-1H-benzo[d]imidazole (BIH) as an electron donor. We found that, despite a low catalytic turnover number, CH₄ was produced only when these porphyrins were facing each other. The close proximity of the cyclic dimers, distinguishing them from a linear Fe porphyrin dimer and monomers, induced multi-electron CO₂ reduction, emphasizing the unique role of their structural arrangement in CH₄ formation. Full article

Bispecific antibodies (BsAbs) can bind to two different antigens, enabling therapeutic concepts that cannot be achieved with monoclonal antibodies. Immuno-competent mice are essential for validating drug discovery concepts, necessitating the development of surrogate mouse BsAbs. In this study, we explored the potential of FAST-Ig^TM, a previously reported BsAb technology, for mouse BsAb production. We investigated charge-based orthogonal Fab mutations to facilitate the correct assembly of heavy and light chains of mouse antibodies and employed knobs-into-holes mutations to facilitate the heterodimerization of heavy chains. We combined five anti-CD3 and two anti-HER2 antibodies in mouse IgG1 and IgG2a subclasses. These 20 BsAbs were analyzed using mass spectrometry or ion exchange chromatography to calculate the percentages of BsAbs with correct chain pairing (BsAb yields). Using FAST-Ig, 19 out of the 20 BsAbs demonstrated BsAb yields of 90% or higher after simple protein A purification from transiently expressed antibodies in Expi293F cells. Importantly, the mouse BsAbs maintained their fundamental physicochemical properties and affinity against each antigen. A Jurkat NFAT-luciferase reporter cell assay demonstrated the combined effects of epitope, affinity, and subclasses. Our findings highlight the potential of FAST-Ig technology for efficiently generating mouse BsAbs for preclinical studies. Full article

Ubiquitination is a process that dictates the lifespan of major histocompatibility complex class II (MHC II)/peptide complexes on antigen-presenting cells. This process is tightly controlled by the levels of ubiquitin ligases, and disruptions in the turnover of MHC II can lead to the improper development of CD4+ T cells within the thymus and hinder the formation of regulatory T cells in the peripheral tissue. To investigate the underlying mechanisms, we utilized dendritic cells lacking the Membrane-associated RING-CH (MARCH) I ubiquitin ligase. We discovered that the overexpression of MARCH I decreases the interaction with LAG-3. Moreover, the MHC II molecules tethered with ubiquitin also showed diminished binding to LAG-3. We employed Diffracted X-ray Blinking (DXB), a technique used for single-molecule X-ray imaging, to observe the protein movements on live cells in real time. Our observations indicated that the normal MHC II molecules moved more rapidly across the cell surface compared to those on the MARCH I-deficient dendritic cells or MHC II KR mutants, which is likely a result of ubiquitination. These findings suggest that the signaling from ubiquitinated MHC II to the T cell receptor differs from the non-ubiquitinated forms. It appears that ubiquitinated MHC II might not be quickly internalized, but rather presents antigens to the T cells, leading to a range of significant immunological responses. Full article

Understanding the cellular environment as molecular crowding that supports the structure-specific functional expression of biomolecules has recently attracted much attention. Time-resolved X-ray observations have the remarkable capability to capture the structural dynamics of biomolecules with subnanometre precision. Nevertheless, the measurement of the intracellular dynamics within live organisms remains a challenge. Here, we explore the potential of utilizing crystallized proteins that spontaneously form intracellular crystals to investigate their intracellular dynamics via time-resolved X-ray observations. We generated transgenic Caenorhabditis elegans specifically expressing the crystallized protein in cells and observed the formation of the protein aggregates within the animal cells. From the toxic-effect observations, the aggregates had minimal toxic effects on living animals. Fluorescence observations showed a significant suppression of the translational diffusion movements in molecules constituting the aggregates. Moreover, X-ray diffraction measurements provided diffraction signals originating from these molecules. We also observed the blinking behaviour of the diffraction spots, indicating the rotational motion of these crystals within the animal cells. A diffracted X-ray blinking (DXB) analysis estimated the rotational motion of the protein crystals on the subnanometre scale. Our results provide a time-resolved X-ray diffraction technique for the monitoring of intracellular dynamics. Full article

Ovarian cancer ranks as the eighth most prevalent form of cancer in women across the globe and stands as the third most frequent gynecological cancer, following cervical and endometrial cancers. Given its resistance to standard chemotherapy and high recurrence rates, there is an urgent imperative to discover novel compounds with potential as chemotherapeutic agents for treating ovarian cancer. Chalcones exhibit a wide array of biological properties, with a particular focus on their anti-cancer activities. In this research, we documented the synthesis and in vitro study of a small library of chalcone derivatives designed for use against high-grade serous ovarian cancer (HGSOC) cell lines, specifically OVCAR-3, OVSAHO, and KURAMOCHI. Our findings revealed that three of these compounds exhibited cytotoxic and anti-proliferative effects against all the tested HGSOC cell lines, achieving IC₅₀ concentrations lower than 25 µM. Further investigations disclosed that these chalcones prompted an increase in the subG1 phase cell cycle and induced apoptosis in OVCAR-3 cells. In summary, our study underscores the potential of chalcones as promising agents for the treatment of ovarian cancer. Full article

Tubulin has been recently reported to form a large family consisting of various gene isoforms; however, the differences in the molecular features of tubulin dimers composed of a combination of these isoforms remain unknown. Therefore, we attempted to elucidate the physical differences in the molecular motility of these tubulin dimers using the method of measurable pico-meter-scale molecular motility, diffracted X-ray tracking (DXT) analysis, regarding characteristic tubulin dimers, including neuronal TUBB3 and ubiquitous TUBB5. We first conducted a DXT analysis of neuronal (TUBB3-TUBA1A) and ubiquitous (TUBB5-TUBA1B) tubulin dimers and found that the molecular motility around the vertical axis of the neuronal tubulin dimer was lower than that of the ubiquitous tubulin dimer. The results of molecular dynamics (MD) simulation suggest that the difference in motility between the neuronal and ubiquitous tubulin dimers was probably caused by a change in the major contact of Gln245 in the T7 loop of TUBB from Glu11 in TUBA to Val353 in TUBB. The present study is the first report of a novel phenomenon in which the pico-meter-scale molecular motility between neuronal and ubiquitous tubulin dimers is different. Full article

Epithelial ovarian cancer (EOC) is the leading cause of death from gynecological cancers in Western countries. High-Grade Serous Ovarian Carcinoma (HGSOC) accounts for 60–70% of EOC and is the most aggressive subtype. Reduced PTPN13 expression levels have been previously correlated with worse prognosis in HGSOC. However, PTPN13’s exact role and mechanism of action in these tumors remained to be investigated. To elucidate PTPN13’s role in HGSOC aggressiveness, we used isogenic PTPN13-overexpressing clones of the OVCAR-8 cell line, which poorly expresses PTPN13, and also PTPN13 CRISPR/Cas9-mediated knockout/knockdown clones of the KURAMOCHI cell line, which strongly expresses PTPN13. We investigated their migratory and invasive capacity using a wound healing assay, their mesenchymal-epithelial transition (EMT) status using microscopy and RT-qPCR, and their sensitivity to chemotherapeutic drugs used for HGSOC. We found that (i) PTPN13 knockout/knockdown increased migration and invasion in KURAMOCHI cells that also displayed a more mesenchymal phenotype and increased expression of the SLUG, SNAIL, ZEB-1, and ZEB-2 EMT master genes; and (ii) PTPN13 expression increased the platinum sensitivity of HGSOC cells. These results suggest that PTPN13 might be a predictive marker of response to platinum salts in HGSOC. Full article

The transient receptor potential vanilloid type 1 (TRPV1) is a multimodal receptor which responds to various stimuli, including capsaicin, protons, and heat. Recent advances in cryo-electron microscopy have revealed the structures of TRPV1. However, due to the large size of TRPV1 and its structural complexity, the detailed process of channel gating has not been well documented. In this study, we applied the diffracted X-ray tracking (DXT) technique to analyze the intracellular domain dynamics of the TRPV1 protein. DXT enables the capture of intramolecular motion through the analysis of trajectories of Laue spots generated from attached gold nanocrystals. Diffraction data were recorded at two different frame rates: 100 μs/frame and 12.5 ms/frame. The data from the 100 μs/frame recording were further divided into two groups based on the moving speed, using the lifetime filtering technique, and they were analyzed separately. Capsaicin increased the slope angle of the MSD curve of the C-terminus in 100 μs/frame recording, which accompanied a shifting of the rotational bias toward the counterclockwise direction, as viewed from the cytoplasmic side. This capsaicin-induced fluctuation was not observed in the 12.5 ms/frame recording, indicating that it is a high-frequency fluctuation. An intrinsiccounterclockwise twisting motion was observed in various speed components at the N-terminus, regardless of the capsaicin administration. Additionally, the competitive inhibitor AMG9810 induced a clockwise twisting motion, which is the opposite direction to capsaicin. These findings contribute to our understanding of the activation mechanisms of the TRPV1 channel. Full article

Indoor air quality (IAQ) influences the health and intellectual productivity of occupants. This paper summarizes studies investigating the relationship between intellectual productivity and IAQ with varying ventilation rates. We conducted a meta-analysis of five studies, with a total of 3679 participants, and performed subgroup analyses (arithmetic, verbal comprehension, and cognitive ability) based on the type of academic performance. The task performance speed and error rate were evaluated to measure intellectual productivity. The effect size of each study was evaluated using the standardized mean difference (SMD). In addition, we calculated a dose-response relationship between ventilation rate and intellectual productivity. The results show that the task performance speed improved, SMD: 0.18 (95% CI: 0.10–0.26), and the error rate decreased, SMD: −0.05 (95% CI: −0.11–0.00), with an increase in ventilation rate. Converting the intervention effect size on the SMD into the natural units of the outcome measure, our analyses show significant improvements in the task performance speed: 13.7% (95% CI: 6.2–20.5%) and 3.5% (95% CI: 0.9–6.1%) in terms of arithmetic tasks and cognitive ability, respectively. The error rate decreased by −16.1% (95% CI: −30.8–0%) in arithmetic tasks. These results suggest that adequate ventilation is necessary for good performance. Full article

The success of the photocatalytic CO₂ reduction using sunlight depends on how visible light is captured and utilized. Zn porphyrins, which are synthetic analogues of chlorophyll and bacteriochlorophyll, have very intense absorption bands in the visible region and are high potential candidates as photosensitizers for CO₂ reduction. However, the use of zinc porphyrins had been limited due to their poor stability under the photocatalytic reduction conditions. We found that the durability of porphyrin during the photocatalytic CO₂ reduction reaction is dramatically improved by combining a metal complex catalyst with the porphyrin so that two or more electrons are not accumulated on the porphyrin. In this perspective, we describe the molecular design of systems that combine Re complexes and porphyrins in detail and their unique reaction mechanisms in the photocatalytic CO₂ reduction. Full article