Mother-to-embryo vitellogenin transport in a viviparous teleost Xenotoca eiseni

魚類がお腹の子供に与える栄養素を解明 --哺乳類が失った遺伝子を利用して胎生機構を獲得--. 京都大学プレスリリース. 2019-10-09.Vitellogenin (Vtg), a yolk nutrient protein that is synthesized in the livers of female animals, and subsequently carried into the ovary, contributes to vitellogenesis in oviparous animals. Thus, Vtg levels are elevated during oogenesis. In contrast, Vtg proteins have been genetically lost in viviparous mammals, thus the yolk protein is not involved in their oogenesis and embryonic development. In this study, we identified Vtg protein in the livers of females during the gestation of the viviparous teleost, Xenotoca eiseni. Although vitellogenesis is arrested during gestation, biochemical assays revealed that Vtg protein was present in ovarian tissues and lumen fluid. The Vtg protein was also detected in the trophotaeniae of the intraovarian embryo. Immunoelectron microscopy revealed that Vtg protein is absorbed into intracellular vesicles in the epithelial cells of the trophotaeniae. Furthermore, extraneous Vtg protein injected into the abdominal cavity of a pregnant female was subsequently detected in the trophotaeniae of the intraovarian embryo. Our data suggest that the yolk protein is one of the matrotrophic factors supplied from the mother to the intraovarian embryo during gestation in X. eiseni

Questionnaire survey on the continuity of home oxygen therapy after a disaster with power outages

AbstractBackgroundAfter the Great East Japan Earthquake, oxygen-dependent patients in areas experiencing power outages could not continue home oxygen therapy (HOT) without oxygen cylinders. The purpose of this study was to examine use of oxygen cylinders in areas experiencing power outages and the effects of HOT interruption on patients' health.MethodsQuestionnaires were mailed to 1106 oxygen-dependent patients and HOT-prescribing physicians in Akita, near the disaster-stricken area. We investigated patients' actions when unable to use an oxygen concentrator and classified the patients based on oxygen cylinder use. Patients who experienced an interruption of or reduction in oxygen flow rate by their own judgment were assigned to the “interruption” and “reduction” groups, respectively; those who maintained their usual flow rate were assigned to the “continuation” group. Differences were tested using analysis of variance and the χ2 tests.ResultsIn total, 599 patients responded to the questionnaire. Oxygen cylinders were supplied to 574 patients (95.8%) before their oxygen cylinders were depleted. Comparison of the continuation (n=356), reduction (n=64), and interruption (n=154) groups showed significant differences in family structure (p=0.004), underlying disease (p=0.014), oxygen flow rate (p<0.001), situation regarding use (p<0.001), knowledge of HOT (p<0.001), and anxiety about oxygen supply (p<0.001). There were no differences in changes in physical condition.ConclusionsMost patients could receive oxygen cylinders after the disaster. Some patients discontinued their usual oxygen therapy, but their overall health status was not affected

A Novel Antigen-Sampling Cell in the Teleost Gill Epithelium With the Potential for Direct Antigen Presentation in Mucosal Tissue

In mammals, M cells can take up antigens through mucosal surfaces of the gut and the respiratory tract. Since M cells are deficient of lysosomes and phagosomes, the antigens are directly delivered to the mucosa-associated lymphoid tissue (MALT) without degradation. In teleost fish, the entire body surface (gills, skin, and intestinal system) is covered by mucus; however, specific antigen-sampling cells have not yet been identified in their mucosal tissues. Here, we show that two phenotypes of antigen-sampling cells take up antigens through epithelial surfaces of the rainbow trout gill. One phenotype of antigen-sampling cells has features of monocyte/macrophage/dendritic cell-type cells; they have large vacuoles in the cytoplasm and express PTPRC (CD45), CD83, IL-1β, and IL-12p40b. The second phenotype exhibits similar characteristics to mammalian M cells; the corresponding cells bind the lectin UEA-1 but not WGA and show expression of M cell marker gene Anxa5. In contrast to mammalian M cells, teleost M-type cells were found to exhibit small vacuoles in their cytoplasm and to express almost all genes related to the “phagosome”, “lysosome,” and “antigen processing and presentation” pathways. Furthermore, MHC class II was constitutively expressed on a fraction of M-type cells, and this expression was significantly increased after antigen uptake, suggesting that the MHC class II is inducible by antigen stimulation. Here, we suggest that teleost M-type cells play a role in the phylogenetically primitive teleost immune system, similar to bona-fide M cells. In addition, the presence of MHC class II expression suggests an additional role in antigen presentation in the gills, which are an organ with high T cell abundance, especially in interbranchial lymphoid tissue. The present results suggest an unconventional antigen presentation mechanism in the primitive mucosal immune system of teleosts, which generally lack highly organized lymphoid tissues. Moreover, the results of this work may be valuable for the development of mucosal vaccines that specifically target M-type cells; mucosal vaccines significantly reduce working costs and the stress that is usually induced by vaccination via injection of individual fish