The concentration of cytoplasmic free calcium (Ca2+) increases in various stimulated cells in a wave (Ca2+ wave) and in periodic transients (Ca2+ oscillations). These phenomena are explained by inositol 1,4,5-trisphosphate (IP3)-induced Ca2+ release (IICR) and Ca(2+)-induced Ca2+ release (CICR) from separate intracellular stores, but decisive evidence is lacking. A monoclonal antibody to the IP3 receptor inhibited both IICR and CICR upon injection of IP3 and Ca2+ into hamster eggs, respectively. The antibody completely blocked sperm-induced Ca2+ waves and Ca2+ oscillations. The results indicate that Ca2+ release in fertilized hamster eggs is mediated solely by the IP3 receptor, and Ca(2+)-sensitized IICR, but not CICR, generates Ca2+ waves and Ca2+ oscillations.

Aquaporin-2 is detectable in the urine, and changes in the urinary excretion of this protein can be used as an index of the action of vasopressin on the kidney.

During maturation of hamster oocytes, the distribution of the endoplasmic reticulum (ER) and inositol 1,4,5-trisphosphate receptors (InsP3Rs) was found to change dramatically, as observed using confocal microscopy with DiI and electron microscopy for the ER and immunohistochemistry for InsP3Rs. In immature oocytes at the germinal vesicle (GV) stage, ER and InsP3Rs were located predominantly in several large masses near the surface and also in the perinuclear region near the surface. In contrast, fine ER networks and low-density InsP3Rs were present in the inner cytoplasm. The ER appeared to be formed as vesicles from annulate lamellae (AL) in the subcortical area. Rises in Ca2+ concentration occurred in the cytoplasm and the GV when immature oocytes were inseminated, but clear Ca2+ waves did not occur. Ca2+ rises began preferentially from the perinuclear region in response to low doses of serotonin or to uniform stimulation of InsP3Rs with photocleavage of caged InsP3. Serum also induced inhomogeneous Ca2+ release, shown by nonpropagating Ca2+ rises at multiple surface sites. Between the GV stage and prometaphase I the number and size of the surface ER masses increased, and the AL disappeared. This quantitative ER maturation was followed by a second step, spatial maturation. After prometaphase I, surface ER masses gradually dispersed to a number of much smaller ER clusters near the surface and, together with the perinuclear mass, were incorporated into thicker ER networks, resulting in a reticular pattern of the ER with small patches of InsP3Rs throughout the mature egg. The ER shifted to the peripheral surface with apposition to cortical granules. These developmental changes in ER Ca2+ stores may account, at least partly, for the acquisition of the ability of an egg to undergo normal fertilization.

Immunoglobulin A nephropathy (IgAN) is the most common primary glomerulonephritis in the world. Here, we identify a cDNA encoding a novel mucin protein, shown previously to be up-regulated in IgAN patients, from a human kidney cDNA library. This protein contains a mucin tandem repeat of 19 amino acids consisting of many threonine, serine, and proline residues and likely to be extensively O-glycosylated; thus, this gene was classified in the mucin family and named MUC20. The human MUC20 gene contains at least four exons and is localized close to MUC4 on chromosome 3q29. We found variations in repeat numbers in the mucin tandem domain, suggesting polymorphism of this region. Northern blot and reverse transcription-PCR analyses revealed that human MUC20 mRNA was expressed most highly in kidney and moderately in placenta, colon, lung, prostate, and liver. Immunohistochemical analysis of human kidney revealed that MUC20 protein was localized in the proximal tubules. Immunoblotting analysis of MUC20 proteins produced in Madin-Darby canine kidney and HEK293 cells indicated the localization of MUC20 protein in a membrane fraction and extensive posttranslational modification. Immunoelectron microscopy of MUC20-producing Madin-Darby canine kidney cells demonstrated that MUC20 protein was localized on the plasma membrane. Expression of MUC20 mRNA in a human kidney cell line was up-regulated by tumor necrosis factor-␣, phorbol 12-myristate 13-acetate, or lipopolysaccharide. Two species of MUC20 mRNA (hMUC20-L and hMUC20-S), resulting from alternative transcription, were identified in human tissue, whereas only one variant was observed in mouse tissues. Mouse MUC20 mRNA was expressed in the epithelial cells of proximal tubules, and the expression increased dramatically with the progression of lupus nephritis in the kidney of MRL/MpJ-lpr/lpr mice.Moreover, the expression of mouse MUC20 was augmented in renal tissues acutely injured by cisplatin or unilateral ureteral obstruction. These characteristics suggest that the production of MUC20 is correlated with development and progression of IgAN and other renal injuries.

We recently developed a matrix-assisted laser desorption/ionization quadrupole ion trap time-of-flight (MALDI-QIT-TOF)-based imaging mass spectrometry (IMS) system. This system enables us to perform structural analyses using tandem mass spectrometry (MS/MS), as well as to visualize phospholipids and peptides in frozen sections. In the retina, phototransduction is regulated by the light-sensitive interaction between visual pigment-coupled receptor proteins, such as rhodopsin, and G proteins, such as transducin. There are some reports that the conformation of rhodopsin is influenced by the composition of phospholipids in the lipid bilayer membrane. However, these results were based on in vitro experiments and have not been analyzed in vivo. In this study, we visualized and identified phospholipids in mouse retinal sections with the MALDI-QIT-TOF-based IMS system. From a spectrum obtained by raster-scanned analysis of the sections, ions with high signal intensities were selected and analyzed by MS/MS. As a result, sixteen ions were identified as being from four diacyl-phosphatidylcholine (PC) species, i.e., PC (16:0/16:0), PC (16:0/18:1), PC (16:0/22:6), and PC (18:0/22:6), with different ion forms. The ion images revealed different distributions on the retinal sections: PC (16:0/18:1) was distributed in the inner nuclear layer and outer plexiform layer, PC (16:0/16:0) in the outer nuclear layer and inner segment, and both PC (16:0/22:6) and PC (18:0/22:6) in the outer segment and pigment epithelium. In conclusion, our in vivo IMS analyses demonstrated a three-zone distribution of PC species on the retinal sections. This approach may be useful for analyzing lipid changes and their contribution to phototransduction in the retina.

Microstereolithography (MSL) is an emerging technology, which is expected to play a key role in the fabrication of micro-and nanoelectronic machines and micro-and nanoelectromechanical systems (MEMS/NEMS).[1] Of the various MSL techniques, multiphoton photopolymerization (MPP) [2][3][4][5][6] has attracted widespread interest owing to its potential use in fabricating intrinsic 3D microstructures such as 3D photonic crystals (PhCs). [7][8][9][10][11] Much effort at developing MPP-MSL has been devoted to improving the resolution of the fabrication approaches at the nanometer scale, [12][13][14][15][16] and to achieve the fabrication of functional microstructures. [7][8][9][10][11]17,18] Photopolymerizable resins such as common photoresists have been widely used in MPP-MSL as photocurable polymeric crosslinking networks to maintain the shape of 3D microstructures after the lithography and post developing processes. To satisfy the requirements for functional MEMS/NEMS, the materials in the 3D microstructures need to be further functionalized, which offers the possibility of adding new functionality targeted at achieving novel applications for MEMS/NEMS. High-efficiency luminescent devices with micrometer-sized features, such as fluorescent microstructures, are of great interest for photonic applications. However, not much research effort has been focused on developing luminescent 3D microstructures. [19][20][21] Analogous to systems such as laser-dye-doped polymers, luminescent semiconductor-polymer nanocomposites are also attractive as luminescent polymeric materials, since various semiconductor nanoparticles (NPs) show unique tunable light emission properties arising from quantum size effects. Recent reports in the literature have focused on the synthesis and light emission properties of semiconductorpolymer nanocomposites. However, to the best of our knowledge, there have not been many reports of photoluminescent 3D microstructures of semiconductor-polymer nanocomposites and their emission properties. One major reason for this is that most nanoparticles are difficult to disperse in the photoresist resins, which tend to be highly viscous. The aggregation of NPs causes the photoresist resin to become opaque, thus degrading the ability to fabricate 3D structures by MPP-MSL techniques. To realize 3D microstructures of luminescent polymer nanocomposites and to facilitate their use as photonic microdevices, it is essential to develop a suitable method for fabricating 3D microstructures from polymer nanocomposites with size control of the embedded NPs. Such an approach is expected to enable the fabrication of color-tunable microstructures and the development of high-efficiency polymer optoelectronic devices.In our previous studies, [22] we have reported the first 3DPhCs of TiO 2 -NP-embedded polymer nanocomposites with a confirmed photonic bandgap (PBG). These PhCs have been fabricated by MPP-MSL using a Ti-ion doped urethane acrylate resin. Furthermore, we have recently demonstrated a 3D PhC based on a CdS-polymer nanoc...

No abstract

The immunohistochemical localization of P400/inositol 1,4,5-trisphosphate (InsP3) receptor protein was studied in developing and adult mouse brain by using monoclonal antibodies. The developmental expression pattern of P400/InsP3 receptor protein differed among different classes of neurons. It was first detected in the somata of immature Purkinje cells at embryonic day 17, in the ventrolateral region of the posterior vermis in the cerebellum. Axonal immunoreactivity within the cerebellar nuclei was first present at postnatal day 3. Neurons in the retrosplenial cortex, the anterior olfactory nucleus, and the CA1 region of the hippocampus expressed immunoreactivity earlier than other regions of the brain. In the adult brain, not only the Purkinje cell but also many other types of cells in many areas of the brain expressed P400/InsP3 receptor, though to a lesser extent. These included the neurons in the striatum, globus pallidus, nucleus accumbens septi, anterior olfactory nucleus, olfactory tubercle, precommissural hippocampus, hippocampus, substantia nigra, cerebral cortex, pons, and certain hypothalamic nuclei. Forebrain cortical regions that receive afferents from the olfactory bulb, such as the anterior olfactory nucleus, olfactory tubercle, prepiriform cortex, entorhinal cortex, and amygdala, exhibited distinct immunoreactivity, while olfactory bulb was almost devoid of staining. Immunoreactivity in the axonal pathways was also found in the limbic-hypothalamic pathways, strionigral projection, and part of the corpus callosum. Results of Western blot analysis and 3H-InsP3 binding assay were consistent with the qualitative regional differences of immunoreactivity demonstrated by immunohistochemical study. The location of InsP3 receptor in the brain correlates well with the InsP3 binding sites demonstrated by an autoradiographic study.