Mechanism of Photoregulated Carotenogenesis in Rhodotorula minuta III. Effect of Certain Nucleic Acid and Protein Inhibitors on Photoinduction of Carotenoid Biosynthesis

Inhibitors of protein and nucleic acid synthesis such as puromycin,cycloheximide, 5-fluorodeoxyuridine and 5-fluorouracil havebeen used to study the dark reactions involved in photoregulationof carotenogenesis in Rhodotorula minuta. The results indicatedthat as already reported in other organisms, carotenogenic enzymesare synthesized first and, in turn, synthesize carotenoids inthe dark. Synthesis of the carotenogenic enzymes was absolutelydependent on oxygen and came to an end within 6 hr at 26?C underaerobic conditions. Photoregulation of this synthesis may occurat the translational level. 5-Fluorodeoxyuridine and 5-fluorouracilacted as chemical inducers of carotenogenesis in Rh. minutagrown in the dark. However, the site of the action of thesechemicals was assumed to be different from that of light, becausethe chemical and light effects on the induction of carotenogenesiswere additive. (Received September 16, 1981; Accepted March 3, 1982)     

11C-methionine positron emission tomography for target delineation of recurrent glioblastoma in re-irradiation planning

Aim

To define the optimal margin on MRI scans in the re-radiation planning of recurrent glioblastoma using methionine positron emission tomography (MET-PET).

Treatment outcomes and late toxicities of intensity-modulated radiation therapy for 1091 Japanese patients with localized prostate cancer

Aim

This study aimed to evaluate the treatment result of intensity-modulated radiation therapy (IMRT) in a large number of Japanese patients with prostate cancer.

Three Distinct Types of Microautophagy Based on Membrane Dynamics and Molecular Machineries

Microautophagy is originally defined as lysosomal (vacuolar) membrane dynamics to directly enwrap and transport cytosolic components into the lumen of the lytic organelle. Molecular details of microautophagy had remained unknown until genetic studies in yeast identified a set of proteins required for the process. Subsequent studies with other experimental model organisms resulted in a series of discoveries that accompanied an expansion of the definition of microautophagy to also encompass endosomal membrane dynamics. These findings, however, still impose puzzling, non‐integrated images as to the molecular mechanism of microautophagy. By reviewing recent studies on microautophagy in various experimental systems, we propose the classification of microautophagy into three types, as the basis for developing a comprehensive view of the process.     

Induction of lung-like cells from mouse embryonic stem cells by decellularized lung matrix

Decellularization of tissues is a recently developed technique mostly used to provide a 3-dimensional matrix structure of the original organ, including decellularized lung tissues for lung transplantation. Based on the results of the present study, we propose new utilization of decellularized tissues as inducers of stem cell differentiation. Decellularized lung matrix (L-Mat) samples were prepared from mouse lungs by SDS treatment, then the effects of L-Mat on differentiation of ES cells into lung cells were investigated. ES cell derived-embryoid bodies (EBs) were transplanted into L-Mat samples and cultured for 2 weeks. At the end of the culture, expressions of lung cell-related markers, such as TTF-1 and SP-C (alveolar type II cells), AQP5 (alveolar type I cells), and CC10 (club cells), were detected in EB outgrowths in L-Mat, while those were not found in EB outgrowths attached to the dish. Our results demonstrated that L-Mat has an ability to induce differentiation of ES cells into lung-like cells.     

Congenic mapping and candidate gene analysis for streptozotocin-induced diabetes susceptibility locus on mouse chromosome 11

Streptozotocin (STZ) has been widely used to induce diabetes in rodents. Strain-dependent variation in susceptibility to STZ has been reported; however, the gene(s) responsible for STZ susceptibility has not been identified. Here, we utilized the A/J-11^SM consomic strain and a set of chromosome 11 (Chr. 11) congenic strains developed from A/J-11^SM to identify a candidate STZ-induced diabetes susceptibility gene. The A/J strain exhibited significantly higher susceptibility to STZ-induced diabetes than the A/J-11^SM strain, confirming the existence of a susceptibility locus on Chr. 11. We named this locus Stzds1 (STZ-induced diabetes susceptibility 1). Congenic mapping using the Chr. 11 congenic strains indicated that the Stzds1 locus was located between D11Mit163 (27.72 Mb) and D11Mit51 (36.39 Mb). The Mpg gene, which encodes N-methylpurine DNA glycosylase (MPG), a ubiquitous DNA repair enzyme responsible for the removal of alkylated base lesions in DNA, is located within the Stzds1 region. There is a close relationship between DNA alkylation at an early stage of STZ action and the function of MPG. A Sanger sequence analysis of the Mpg gene revealed five polymorphic sites in the A/J genome. One variant, p.Ala132Ser, was located in a highly conserved region among rodent species and in the minimal region for retained enzyme activity of MPG. It is likely that structural alteration of MPG caused by the p.Ala132Ser mutation elicits increased recognition and excision of alkylated base lesions in DNA by STZ.

     

Characterization of Mesonephric Cells That Migrate into the XY Gonad during Testis Differentiation

In mouse fetal gonads, sex differentiation begins at 10.5-11.5 days postcoitum (dpc). With XY gonads of 12.5 dpc, cord-like structures are visible and stromal cells migrate from adjacent mesonephros, unlike in XX gonads. However, the migrated mesonephric cells, except for the endothelial cells, have not been specifically identified because they have not expressed differentiation markers over the course of organ coculture in previous experiments. In this study, we have for the first time succeeded in isolating only the mesonephric cells that migrate into the XY gonad from the mesonephros with alive and then cultured these cells in vitro through the use of an organ coculture system using EGFP-transgenic mice and a FACS Vantage. The migrated and isolated cells were used for morphological and molecular characterization. The migrated mesonephric cells contained three cell forms; a sharp cell form, a round cell form, and a cluster-forming cell. The sharp cells have the characters of peritubular myoid cells. The round cells and cluster-forming cells have the potential to differentiate into Leydig cells, as some of them are 3beta-HSD-positive. In in vitro culture of migrated mesonephric cells, the cluster-forming cells proliferated well and then differentiated into round cells, suggesting that the cluster-forming cells may be stem or precursor cells for the round cells. Thus, our findings provide important information related to the migration and differentiation of migrated mesonephric cells in the XY gonad.