Kyoto University

About: Kyoto University is a education organization based out in Kyoto, Japan. It is known for research contribution in the topics: Catalysis & Population. The organization has 85837 authors who have published 217215 publications receiving 6526826 citations. The organization is also known as: Kyōto University & Kyōto daigaku.

Subcapsular encounter and complement-dependent transport of immune complexes by lymph node B cells

Abstract: The mechanism of B cell–antigen encounter in lymphoid tissues is incompletely understood. It is also unclear how immune complexes are transported to follicular dendritic cells. Here, using real-time two-photon microscopy we noted rapid delivery of immune complexes through the lymph to macrophages in the lymph node subcapsular sinus. B cells captured immune complexes by a complement receptor–dependent mechanism from macrophage processes that penetrated the follicle and transported the complexes to follicular dendritic cells. Furthermore, cognate B cells captured antigen-containing immune complexes from macrophage processes and migrated to the T zone. Our findings identify macrophages lining the subcapsular sinus as an important site of B cell encounter with immune complexes and show that intrafollicular B cell migration facilitates the transport of immune complexes as well as encounters with cognate antigen.

Rational Designs for Highly Proton-Conductive Metal-Organic Frameworks

Abstract: A novel metal−organic framework (MOF), (NH4)2(adp)[Zn2(ox)3]·3H2O (1) was synthesized and its structure was determined. We propose three types of rational design to introduce proton carriers into MOFs. The simplest method is to introduce them directly as counterions such as NH4+, H3O+, and HSO4− into the pores of frameworks (type I). The second is to put acid groups on frameworks, the protons being provided from them (type II). The third is to incorporate acidic molecules into voids (type III). 1 demonstrated a combination of two of the concepts by introducing NH4+ ions using the anionic framework (type I) and putting carboxyl end groups of adipic acid in a honeycomb-shaped void (type III). 1 showed a superprotonic conductivity of 10−2 S cm−1 at ambient temperature, comparable to organic polymers such as Nafion, which is in practical use in fuel cells. This is the first example of an MOF to exhibit a superprotonic conductivity of 10−2 S cm−1 at ambient temperature.

Molecular Mechanism of Class Switch Recombination: Linkage with Somatic Hypermutation

Abstract: ▪ Abstract Class switch recombination (CSR) and somatic hypermutation (SHM) have been considered to be mediated by different molecular mechanisms because both target DNAs and DNA modification products are quite distinct. However, involvement of activation-induced cytidine deaminase (AID) in both CSR and SHM has revealed that the two genetic alteration mechanisms are surprisingly similar. Accumulating data led us to propose the following scenario: AID is likely to be an RNA editing enzyme that modifies an unknown pre-mRNA to generate mRNA encoding a nicking endonuclease specific to the stem-loop structure. Transcription of the S and V regions, which contain palindromic sequences, leads to transient denaturation, forming the stem-loop structure that is cleaved by the AID-regulated endonuclease. Cleaved single-strand tails will be processed by error-prone DNA polymerase-mediated gap-filling or exonuclease-mediated resection. Mismatched bases will be corrected or fixed by mismatch repair enzymes. CSR ends are...

Failure of Parturition in Mice Lacking the Prostaglandin F Receptor

Abstract: Mice lacking the gene encoding the receptor for prostaglandin F2α (FP) developed normally but were unable to deliver normal fetuses at term. Although these FP-deficient mice showed no abnormality in the estrous cycle, ovulation, fertilization, or implantation, they did not respond to exogenous oxytocin because of the lack of induction of oxytocin receptor (a proposed triggering event in parturition), and they did not show the normal decline of serum progesterone concentrations that precedes parturition. Ovariectomy at day 19 of pregnancy restored induction of the oxytocin receptor and permitted successful delivery in the FP-deficient mice. These results indicate that parturition is initiated when prostaglandin F2α interacts with FP in ovarian luteal cells of the pregnant mice to induce luteolysis.