ヘッジファンド運用戦略の事後評価とリスク計測モデルの検討

要旨あり金融リスクの統計解析研究詳

A connecter-like factor, CacA, links RssB/RpoS and the CpxR/CpxA two-component system in Salmonella

BACKGROUND: Bacteria integrate numerous environmental stimuli when generating cellular responses. Increasing numbers of examples describe how one two-component system (TCS) responds to signals detected by the sensor of another TCS. However, the molecular mechanisms underlying this phenomenon remain poorly defined. RESULTS: Here, we report a connector-like factor that affects the activity of the CpxR/CpxA two-component system in Salmonella enterica serovar Typhimurium. We isolated a clone that induced the expression of a cpxP-lac gene fusion from a high-copy-number plasmid pool of random Salmonella genomic fragments. A 63-amino acid protein, CacA, was responsible for the CpxA/CpxR-dependent activation of the cpxP gene. The CpxR-activated genes cpxP and spy exhibited approximately 30% and 50% reductions in transcription, respectively, in a clean cacA deletion mutant strain in comparison to wild-type. From 33 response regulator (RR) deletion mutants, we identified that the RssB regulator represses cacA transcription. Substitution mutations in a conserved -10 region harboring the RNA polymerase recognition sequence, which is well conserved with a known RpoS -10 region consensus sequence, rendered the cacA promoter RpoS-independent. The CacA-mediated induction of cpxP transcription was affected in a trxA deletion mutant, which encodes thioredoxin 1, suggesting a role for cysteine thiol-disulfide exchange(s) in CacA-dependent Cpx activation. CONCLUSIONS: We identified CacA as an activator of the CpxR/CpxA system in the plasmid clone. We propose that CacA may integrate the regulatory status of RssB/RpoS into the CpxR/CpxA system. Future investigations are necessary to thoroughly elucidate how CacA activates the CpxR/CpxA system

Precipitant-Free Lysozyme Crystals Grown by Centrifugal Concentration Reveal Structural Changes

The three-dimensional (3D) structure of a protein molecule in its crystal need not correspond to that found in vivo in many cases, since we usually crystallize protein molecules using precipitants (salts, organic solvents, polymeric electrolytes, etc.), and the precipitants are often incorporated into crystals along with the protein molecules. Although precipitant-free crystallization methods would solve these problems, such methods had not yet been established. We have achieved a novel precipitant-free crystallization method by liquid-liquid phase separation during the centrifugal concentration of lysozyme in ultra-pure water. In the 3D structure of the precipitant-free crystal, lysozyme loses a sodium cation and changes the position of Ser 72. Deionization of the solution also appears to induce a change in the position of Asp 101 and an increase in the activity of lysozyme

Structural Basis of the Autophagy-Related LC3/Atg13 LIR Complex: Recognition and Interaction Mechanism

SummaryAutophagy is a bulk degradation pathway that removes cytosolic materials to maintain cellular homeostasis. The autophagy-related gene 13 (Atg13) and microtubule associate protein 1 light chain 3 (LC3) proteins are required for autophagosome formation. We demonstrate that each of the human LC3 isoforms (LC3A, LC3B, and LC3C) interacts with Atg13 via the LC3 interacting region (LIR) of Atg13. Using X-ray crystallography, we solved the macromolecular structures of LC3A and LC3C, along with the complex structures of the LC3 isoforms with the Atg13 LIR. Together, our structural and binding analyses reveal that the side-chain of Lys49 of LC3 acts as a gatekeeper to regulate binding of the LIR. We verified this observation by mutation of Lys49 in LC3A, which significantly reduces LC3A positive puncta formation in cultured cells. Our results suggest that specific affinity of the LC3 isoforms to the Atg13 LIR is required for proper autophagosome formation

Intra-Abdominal Bleeding during Pregnancy, Preterm Delivery, and Placental Polyp in a Long-Term Survivor of Neuroblastoma: A Case Report

Background. There are few reports of pregnancies in long-term survivors of pelvic neuroblastoma. Case. A 30-year-old Japanese woman with a history of pelvic neuroblastoma in her childhood, which was treated with surgical resection, chemotherapy, and radiation. Her pregnancy continued with conservative management, but she delivered a 510 g female infant at 23 weeks of gestation due to sudden onset of labor pain. She also had a placental polyp and developed massive postpartum bleeding. Conclusion. Cancer treatment, especially radiation therapy, in childhood may cause adverse outcomes during pregnancy in long-term survivors of neuroblastoma

How to use the Web-version LEXIS (Legal Text Retrieval System)

In the class of "legal information processing", students are studying how to use LEXIS (Legal Text Retrieval System). LEXIS is a legal online data base in the United States of America and serviceable to lawyers in the world. We can reach several purposes for legal information processing. Now, we get the new Web-version LEXIS and its use is very convenience. But in teaching , we need a new text and manual for students. So, we planned to make a new manual on using Web-version LEXIS for students, graduate students, and teachers of related subjects in order for them to master how to handle it