Origin of renal proximal tubular injuries by Fe(III)-nta chelate

Interaction between apo-transferrin and several iron(III) chelates has been investigated in terms of the capillary electrophoresis method. Based on the results, it has been clarified that (i) a binuclear iron(III) unit with an oxo-bridge is necessary for the facile transfer of an iron atom from the iron(III) chelate to apo-transferrin, and (ii) the renal proximal tubular injuries by Fe(III)-nitrilotriacetate (Fe-nta) should be due to the unique binuclear structure of this complex, which gives a peroxide adduct of the binuclear Fe-nta in the presence of glutathione cycle and oxygen.     

Finding of 132, 173‐cyclopheophorbide a enol as a degradation product of chlorophyll in shrunk zooxanthellae of the coral Montipora digitata

We examined the morphology and pigment composition of zooxanthellae in corals subjected to normal temperature (27°C) and thermal stress (32°C). We observed several normal and abnormal morphological types of zooxanthellar cells. Normal cells were intact and their chloroplasts were unbroken (healthy); abnormal cells were shrunken and had partially degraded or broken chloroplasts, or they were bleached and without chloroplasts. At 27°C, most healthy zooxanthellar cells were retained in the coral tissue, whereas shrunken zooxanthellae were expelled. Under thermal stress, the abundance of healthy zooxanthellae declined and the proportion of shrunken/abnormal cells increased in coral tissues. The rate of algal cell expulsion was reduced under thermal stress. Within the shrunken cells, we detected the presence of a chl‐like pigment that is not ordinarily found in healthy zooxanthellae. Analysis of the absorption spectrum, absorption maxima, and retention time (by HPLC) indicated that this pigment was 13², 17³‐cyclopheophorbide a enol (cPPB‐aE), which is frequently found in marine and lacustrine sediments, and in protozoans that graze on phytoplankton. The production of cPPB‐aE in shrunken zooxanthellae suggests that the chls have been degraded to cPPB‐aE, a compound that is not fluorescent. The lack of a fluorescence function precludes the formation of reactive oxygen species. We therefore consider the formation of cPPB‐aE in shrunken zooxanthellae to be a mechanism for avoiding oxidative stress.     

A Cytotoxic Antibody Recognizing Lacto-N-fucopentaose I (LNFP I) on Human Induced Pluripotent Stem (hiPS) Cells

We have generated a mouse monoclonal antibody (R-17F, IgG1 subtype) specific to human induced pluripotent stem (hiPS)/embryonic stem (ES) cells by using a hiPS cell line as an antigen. Triple-color confocal immunostaining images of hiPS cells with R-17F indicated that the R-17F epitope was expressed exclusively and intensively on the cell membranes of hiPS cells and co-localized partially with those of SSEA-4 and SSEA-3. Lines of evidence suggested that the predominant part of the R-17F epitope was a glycolipid. Upon TLC blot of total lipid extracts from hiPS cells with R-17F, one major R-17F-positive band was observed at a slow migration position close to that of anti-blood group H1(O) antigen. MALDI-TOF-MS and MSⁿ analyses of the purified antigen indicated that the presumptive structure of the R-17F antigen was Fuc-Hex-HexNAc-Hex-Hex-Cer. Glycan microarray analysis involving 13 different synthetic oligosaccharides indicated that R-17F bound selectively to LNFP I (Fucα1–2Galβ1–3GlcNAcβ1–3Galβ1–4Glc). A critical role of the terminal Fucα1–2 residue was confirmed by the selective disappearance of R-17F binding to the purified antigen upon α1–2 fucosidase digestion. Most interestingly, R-17F, when added to hiPS/ES cell suspensions, exhibited potent dose-dependent cytotoxicity. The cytotoxic effect was augmented markedly upon the addition of the secondary antibody (goat anti-mouse IgG1 antibody). R-17F may be beneficial for safer regenerative medicine by eliminating residual undifferentiated hiPS cells in hiPS-derived regenerative tissues, which are considered to be a strong risk factor for carcinogenesis.     

Tracking the Stejneger's stonechat Saxicola stejnegeri along the East Asian–Australian Flyway from Japan via China to southeast Asia

The East Asian–Australian Flyway spans from north Asia to Australia and is the world's richest birds' flyway because it involves > 40% of global migratory bird species. However, information is lacking on individual migratory routes and non‐breeding grounds for small land birds using this flyway. Here, we present the first migration tracks of the songbird Stejneger's stonechat Saxicola stejnegeri from this part of the world using light‐level geolocators. This species depends on grasslands during the entire annual cycle and was captured and equipped with tracking devices in Hokkaido, northern Japan. All individuals traveled through southern Primorye or eastern Heilongjiang (Russia/China) before flying southward via central China toward their major non‐breeding grounds in southeast Asia (China, Laos, Cambodia, Thailand, and Vietnam). Individual stonechats spent 42–70 d en route during their autumn migration. Both the major non‐breeding grounds and the stopover sites are likely to pose challenges to the persistence of this species, because these habitats are currently degraded and will likely be lost in the near future due to intensified agriculture and the establishment of permanent croplands. Moreover, the areas used by Stejneger's stonechat during migration largely overlapped with illegal trapping areas in northeastern China.     

Novel Synthesis of α-Amino Acids via Cyanosilylation of Schiff Bases

We studied the in vivo dynamics of enhanced green fluorescent protein-tagged clathrin light chain a (GFP-CLCa) at the trans-Golgi network (TGN) in MDA-MB-435 cells. The intensity of fluorescence signals of GFP-CLCa periodically increased and decreased at the TGN approximately every 100 s. This suggests that the formation of clathrin-coated pits occurs synchronously and periodically at the TGN.     

Different responsiveness of the chorda tympani and glossopharyngeal nerves to L-lysine in mice

Differential taste responsiveness and functional role of thetwo taste nerves, the chorda tympani (CT) and die glossopharyngeal(GL), were studied in mice by examining neural and behavioralresponses to an essential amino acid, L-lysine (Lys). Relativeresponses to Lys were larger in the GL than in the CT nerve.The neural threshold for the Lys response was about 2.5 logunits lower in the GL (about 1.0 µM) than in the CT nerve(about 300 µM). An analysis of concentration-responserelationships suggests a possibility that there are two differentreceptors (high and low affinity types) for Lys showing differentdissociation constants. The posterior tongue region possessesboth types, while the anterior region possesses only the lowaffinity type. Behavioral aversion threshold for Lys in intact mice, measuredby use of a single bottle test, was about 1.0 µM. Thisthreshold was the same as its neural threshold in the GL nerve.Animals whose bilateral GL nerves were sectioned showed a higheraversion threshold (about 300 µM) which was the same asthe neural threshold in the CT nerve. An aversion conditionedto Lys significantly generalized to L-arginine in the intactand CT-denervated mice, and L-arginine and L-histidine in theGL-denervated mice, but the generalization pattern across varioustaste stimuli including the four basic taste stimuli (NaCl,HCl, quinine HCl and sucrose) did not prominently differ amongthe intact, the GL-denervated and CT-denervated mice. These results suggest that taste sensitivity to Lys is higherin the GL than in the CT nerve, but taste quality informationfor Lys conveyed by two taste nerves is not largely different.