In Escherichia coli, the ATP-bound form of DnaA (ATP–DnaA) promotes replication initiation. During replication, the bound ATP is hydrolyzed to ADP to yield the ADP-bound form (ADP–DnaA), which is inactive for initiation. The chromosomal site DARS2 facilitates the regeneration of ATP–DnaA by catalyzing nucleotide exchange between free ATP and ADP bound to DnaA. However, the regulatory mechanisms governing this exchange reaction are unclear. Here, using in vitro reconstituted experiments, we show that two nucleoid-associated proteins, IHF and Fis, bind site-specifically to DARS2 to activate coordinately the exchange reaction. The regenerated ATP–DnaA was fully active in replication initiation and underwent DnaA–ATP hydrolysis. ADP–DnaA formed heteromultimeric complexes with IHF and Fis on DARS2, and underwent nucleotide dissociation more efficiently than ATP–DnaA. Consistently, mutant analyses demonstrated that specific binding of IHF and Fis to DARS2 stimulates the formation of ATP–DnaA production, thereby promoting timely initiation. Moreover, we show that IHF–DARS2 binding is temporally regulated during the cell cycle, whereas Fis only binds to DARS2 in exponentially growing cells. These results elucidate the regulation of ATP–DnaA and replication initiation in coordination with the cell cycle and growth phase.

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To clarify competition between FeAs-based superconductivity and antiferromagnetism of Eu 2+ , and the superconducting properties in EuFe 2 As 2 , we investigated a Ca-substituted sample, Eu 0.5 Ca 0.5 Fe 2 As 2 , under high pressure. Under ambient pressure, the sample exhibits a spin-density-wave (SDW) transition at T SDW = 191 K and antiferromagnetic order at T N = 4 K, but no evidence of superconductivity down to 2 K. The Ca-substitution certainly weakens the antiferromagnetism. With increasing pressure, T SDW shifts to lower temperature and becomes more unclear. Above 1.27 GPa, pressure-induced superconductivity with zero resistivity is observed at around T c = 20 K. At 2.14 GPa, T c reaches a maximum value of 24 K and the superconducting transition becomes sharpest. The chemical pressure and the suppression of Eu magnetic order induced by Ca substitution enlarge the zero resistivity region compared to pure EuFe 2 As 2 .

To elucidate competition between the Fe-based superconductivity and the antiferromagnetic order of Eu 2+ , the electrical resistivity of Eu 0.85 Ca 0.15 Fe 2 As 2 under high pressure is presented. Under ambient pressure, the Fe-based spin-density-wave (SDW) transition and the antiferromagnetic ordering (AFM) of Eu 2+ are observed at T SDW = 190 K and T N = 17 K, respectively. With applying pressure, the Fe-based superconductivity with T c ∼ 25 K appears above 1.5 GPa, accompanying collapse of the SDW transition. Compared with EuFe 2 As 2 , T c is close to T N , which implies strong competition between the superconductivity and the AFM. This competition would lead to non-zero resistivity at lowest temperature.

Aims The Academic Research Consortium for High Bleeding Risk (ARC-HBR) presents a bleeding risk assessment in antithrombotic therapy for patients post percutaneous coronary intervention (PCI). In Japanese patients, heart failure (HF), peripheral vascular disease, and frailty are established as bleeding risk factors in addition to ARC-HBR. However, it is unknown whether left ventricular function or severity of HF is associated with HBR. The aim of this study was to investigate the association between the severity of HF measured by BNP and future bleeding events after PCI. Methods Clinical Deep Data Accumulation System (CLIDAS), a multicenter database with 7 tertiary medical hospitals in JAPAN, was developed to collect data directly for patient characteristics, medications, laboratory test, physiological test, cardiac catheterization and PCI treatment in electronic medical records using Standardized Structured Medical Information eXchange Extended Storage (SS-MIX). This retrospective analysis using CLIDAS database included 7160 patients who underwent PCI during April 2014 and March 2020 in the participating hospitals and also who have completed 3-year follow-up were divided into two groups: No HF (n=6645) and HF (n=515). HF patients were furthermore divided based on high BNP (≥100 pg/ml) group (n=384) and low BNP (<100 pg/ml) group (n=131). Primary outcome was defined as bleeding events according to the moderate and severe bleeding in the GUSTO classification. In addition, secondary endpoint was major adverse cardiovascular events (MACE) defined as a composite of cardiac death, myocardial infraction and stroke. Results Multivariable Cox regression adjusted for age, sex, BMI, acute coronary syndrome, hypertension, diabetes, dyslipidemia, chronic kidney disease, hemodialysis, previous PCI, previous coronary artery bypass grafting, prior myocardial infraction, prior stroke, prior atrial fibrillation, prior PVD, left main trunk disease, multivessel disease, and anticoagulants use showed that HF with high BNP was significantly associated with bleeding events (hazard ratio [HR], 1.66; 95% confidence interval [CI], 1.10–2.50), MACE (HR, 2.16; 95% CI, 1.60–2.90), and all-cause death (HR, 1.74; 95% CI, 1.30–2.33), but not HF with low BNP. Conclusions The CLIDAS real-world database revealed that HF with high BNP was associated with future bleeding events, suggesting that bleeding risk might be altered depending on severity of HF. Funding Acknowledgement Type of funding sources: None.