A Novel Method for Screening Monoclonal Antibodies Reacting with Antigenic Determinants on Soluble Antigens; A Reversed Indirect-Enzyme Linked Immunosorbent Assay(RI-ELISA)

A novel screening method was established to select new monoclonal antibodies which react with unknown antigenic determinants on molecules bearing antigen determinants reactive with established monoclonal antibodies. This new method is a sandwich assay termed "reversed indirect-enzyme linked immunosorbent assay" (RI-ELISA). Goat antimouse immunoglobulin antibodies are used as the primary immobilized antibody in this assay. They allow the non-purified monoclonal antibodies contained in hybridoma culture supernatants to bind to the microtest plate for enzyme immunoassay (EIA plate) much more efficiently than in the usual sandwich assay where the non-purified monoclonal antibodies are adsorbed directly to the polystyrene surface. The antigen solution is then reacted with the monoclonal antibodies and thereafter enzyme labeled monoclonal antibody with known specificity is added. Therefore, if the hybridoma culture supernatant contains monoclonal antibodies which were bound to the EIA plate and react with antigenic determinants on the soluble molecules which have antigen determinants recognized by the enzyme labeled antibody, the enzyme labeled antibodies will bind to induce an enzymatic reaction. The most important technical consideration in the RI-ELISA is the inhibition of direct binding of the enzyme labeled monoclonal antibodies to free sites remaining in the immobilized goat anti-mouse immunoglobulins antibodies. This problem could be effectively overcome by using normal mouse serum as blocking substance. These studies indicate that the RI-ELISA may be a useful screening method for selecting new monoclonal antibodies which react with unknown antigenic determinants on soluble molecules

NELF interacts with CBC and participates in 3 \u27 end processing of replication-dependent histone rnRNAs

Negative elongation factor (NELF) is a four subunit transcription elongation factor that has been implicated in numerous diseases ranging from neurological disorders to cancer. Here we show that NELF interacts with the nuclear cap binding complex (CBC), a multifunctional factor that plays important roles in several mRNA processing steps, and the two factors together participate in the 3′ end processing of replication-dependent histone mRNAs, most likely through association with the histone stem-loop binding protein (SLBP). Strikingly, absence of NELF and CBC causes aberrant production of polyadenylated histone mRNAs. Moreover, NELF is physically associated with histone gene loci and forms distinct intranuclear foci that we call NELF bodies, which often overlap with Cajal bodies and cleavage bodies. Our results point to a surprising role of NELF in the 3′ end processing of histone mRNAs and also suggest that NELF is a new factor that coordinates different mRNA processing steps during transcription

FXYD3 functionally demarcates an ancestral breast cancer stem cell subpopulation with features of drug-tolerant persisters

乳がんの再発を起こす原因細胞を解明. 京都大学プレスリリース. 2023-11-16.The heterogeneity of cancer stem cells (CSCs) within tumors presents a challenge in therapeutic targeting. To decipher the cellular plasticity that fuels phenotypic heterogeneity, we undertook single-cell transcriptomics analysis in triple-negative breast cancer (TNBC) to identify subpopulations in CSCs. We found a subpopulation of CSCs with ancestral features that is marked by FXYD domain–containing ion transport regulator 3 (FXYD3), a component of the Na⁺/K⁺ pump. Accordingly, FXYD3⁺ CSCs evolve and proliferate, while displaying traits of alveolar progenitors that are normally induced during pregnancy. Clinically, FXYD3⁺ CSCs were persistent during neoadjuvant chemotherapy, hence linking them to drug-tolerant persisters (DTPs) and identifying them as crucial therapeutic targets. Importantly, FXYD3⁺ CSCs were sensitive to senolytic Na⁺/K⁺ pump inhibitors, such as cardiac glycosides. Together, our data indicate that FXYD3⁺ CSCs with ancestral features are drivers of plasticity and chemoresistance in TNBC. Targeting the Na⁺/K⁺ pump could be an effective strategy to eliminate CSCs with ancestral and DTP features that could improve TNBC prognosis

野火的活動における境界の構成と変容： 超小型衛星開発プロジェクトのエスノグラフィーを通した活動理論的分析

In recent years, there has been a growing interest in "wildfire activities" (Engeström, 2009), in which people are loosely connected through common interests, and these activities spread like wildfire. The reason for this is largely due to the development of online communities. The purpose of this paper is to describe and analyze how boundaries in wildfire activities are constructed and transformed through an ethnography of a nanosatellite development project as an avocation by such an online community. The results show that boundaries in wildfire activities are constructed and transformed through tools that produce "bounded objective" objects, "passive" peer production enabled by bounded objective objects, practices that concretize objects, temporal boundaries and formalization of electronic mobility, and invisible, therefore visualized boundaries

Plasmonic Manipulation of Color and Morphology of Single Silver Nanospheres

Optical control of size, shape, or orientation of a metal nanoparticle is important for development of nanoscale optical devices and elements of photonic circuits. Thus far, however, independent control of two or more parameters has not yet been achieved. Here we place a simple spherical Ag nanoparticle on TiO₂ with high refractive index and separate a plasmon mode localized at the Ag-TiO₂ interface from the other mode distributed over the nanoparticle. Selective excitation of each mode gives rise to a corresponding morphological change and selective suppression of the plasmon mode, resulting in multicolor changes of scattering light from orange to red, green, or a dark color