栄養欠乏状態における Phytophthora capsici LEON. の菌糸生長と遊走子のうの形成(予報)(農学部門)

本報告は培地栄養ひいては体内栄養の欠乏状態に陥った際におけるPhytophthora capsici LEON.の遊走子のう形成について研究を行なったものである。栄養欠乏培地に菌を移植すると, 後培地に栄養が含まれているほど遊走子のう形成は遅くなる。したがって素寒天培地よりもアガロース培地で形成量が多い。この場合前培養が栄養欠乏していて菌の発育が弱々しい時は後培地では遊走子のうを形成しないし, 菌糸も伸長しない。移植に際して持ち込まれる菌体外栄養を除くため液体中で前培養し, 充分水洗して後培地に移すと前培養の栄養に富んでいるところに育ったものほど菌体量が多くなるが遊走子のうの形成は遅れる。前培養の糖濃度は遊走子のう形成には後培養の際ほど影響を与えないが, 菌体量が増加することによって間接的には影響しているようである。これらの結果から菌体内の栄養状態と遊走子のう形成との関係を模式図に表わして説明を加えた。Zoosporangia formation of Phytophthora capsici LEON. (stock no. 6) under poor nutritional conditions were studied. Mycelial development of the fungus was measured on several agar media such as oat meal decoction, Czapek, cucumber decoction and potato decoction. Among these, oat meal decoction agar was most effective for both mycelial growth and zoosporangia formation. On Czapek medium hypha grew rapidly but the mycelium was not so dense as on other media and zoosporangia were not produced. When sucrose was removed from Czapek medium, hypha became more thin but formed many zoosporangia. Water agar was more effective than no sugar Czapek medium for the zoosporangia formation. Water agarose (1%) was the most effective. In these experiments, carryover of nutrients by the inoculum was suspected to contribute to the growth and zoosporangia formation. Mycelial mat was thoroughly washed with sterile distiled water in two bottles to remove the effect of preculture medium and transferred to distiled water to see the net contribution of stored substance to the hyphal growth and zoosporangia formation. The fungus grown in common potato decoction medium took more days to produce zoosporangia after transfer to the second medium than the diluted ones. Dilution of potato dextrose medium decreased the growth of fungus but accelerated the production of zoosporangia. When the fungus was precultured in a poor nutrient medium, the growth after transference was poor and no zoosporangium was produced. From these results we proposed a schmatic diagram for the growth and zoosporangia formation of this fungus under different nutritional conditions

eROSITA Final Equatorial-Depth Survey (eFEDS): eFEDS X-ray view of WERGS Radio Galaxies selected by the Subaru/HSC and VLA/FIRST survey

We construct the eROSITA X-ray catalog of radio galaxies discovered by the WERGS survey that is made by the cross-matching of the wide-area Subaru/HSC optical survey and VLA/FIRST 1.4 GHz radio survey. We find 393 eROSITA detected radio galaxies in the 0.5--2 keV band in the eFEDS field covering 140~deg$^2$. Thanks to the wide and medium depth eFEDS X-ray survey, the sample contains the rare and most X-ray luminous radio galaxies above the knee of the X-ray luminosity function, spanning 44<log L(0.5-2keV,abs)<46.5 at $1<z<4$. Based on the X-ray properties obtained by the spectral fitting, 37 sources show obscured AGN signature with $\log (N_\mathrm{H}/\mathrm{cm}^{-2})>22$. Those obscured and radio AGN reside in $0.4<z<3.2$, indicating that they are obscured counterparts of the radio-loud quasar, which are missed in the previous optical quasar surveys. By combining radio and X-ray luminosities, the jet production efficiency $\eta_\mathrm{jet}$ is investigated, and we find 14 sources with extremely high jet production efficiency at $\eta_\mathrm{jet}\approx1$. This high $\eta_\mathrm{jet}$ value might be a result of 1) the decreased radiation efficiency of $\eta_\mathrm{rad}<0.1$ due to the low accretion rate for those sources and/or 2) the boosting due to the decline of $L_\mathrm{bol}$ by a factor of 10--100 by keeping $P_\mathrm{jet}$ constant in the previous Myr, indicating the experience of the AGN feedback. Finally, inferring the BH masses from the stellar-mass, we find that X-ray luminous sources show the excess of the radio emission with respect to the value estimated from the fundamental plane. Such radio emission excess cannot be explained by the Doppler booming alone, and therefore disk-jet connection of X-ray luminous eFEDS-WERGS is fundamentally different from the conventional fundamental plane which mainly covers low accretion regime.Comment: 20 pages, 11 figures, accepted for publication in A&

Overexpressed HIF-2α in Endothelial Cells Promotes Vascularization and Improves Random Pattern Skin Flap Survival

Background: The local skin flap procedure is very useful for reconstruction. However, flap necrosis caused by circulatory failure can occur at its distal portion. Hypoxia-inducible factors (HIFs) in endothelial cells (ECs) help to maintain ECs and promote vascularization, and HIF-2α is abundantly expressed in ECs. However, the mechanisms of action of HIF-2α in ECs are not yet fully understood. The aim of this study was to evaluate the in vivo effects of overexpression of HIF-2α in ECs on skin flap survival. Methods: A random pattern skin flap (1.0 × 3.0 cm) was elevated on the dorsum of transgenic mice (Tg mice) with EC-specific HIF-2α conditional overexpression and wild-type littermate control mice (n = 6). Flap survival was evaluated on postoperative day 7. Tissue samples from the skin flaps were harvested and analyzed using Western blotting, quantitative reverse transcriptase-polymerase chain reaction, and immunohistochemistry. Results: The HIF-2α mRNA and protein levels were significantly increased in the Tg mice when compared with control mice. Tg mice had significantly increased skin flap survival areas (72.0% ± 2.7%) when compared with wild-type mice (45.7% ± 1.1%). Moreover, histological examination revealed an increase in the subcutaneous blood vessel counts in the Tg mice. Conclusions: Specific overexpression of HIF-2α in ECs promoted vascularization and enhanced skin flap survival in vivo in a mouse model