Hyaluronic acid (HA), a natural anionic mucopolysaccharide, can be deposited onto the cationic surface of DNA/polyethyleneimine (PEI) complexes to recharge the surface potential and reduce ...nonspecific interactions with proteins. HA can also be used as a ligand to target specific cell receptors. Furthermore, HA-coating enhanced the transcriptional activity of the plasmid/PEI complexes, probably by loosening the tight binding between DNA and PEI, which facilitated the approach of transcription factors. Amphoteric HA derivative having spermine side chains (Spn-HA) with a structure similar to HMG protein showed higher transcription-enhancing activity than HA. Plasmid/PEI/Spn-HA ternary complex exhibited 29-fold higher transgene expression efficiency than naked plasmid/PEI complexes in CHO cells.
In the southern Kanto region of Japan, where the Philippine Sea plate is descending at the Sagami trough, two different types of large interplate earthquakes have occurred repeatedly. The 1923 ...(Taisho) and 1703 (Genroku) Kanto earthquakes characterize the first and second types, respectively. A reliable source model has been obtained for the 1923 event from seismological and geodetical data, but not for the 1703 event because we have only historical records and paleo-shoreline data about it. We developed an inversion method to estimate fault slip distribution of interplate repeating earthquakes from paleo-shoreline data on the idea of crustal deformation cycles associated with subduction-zone earthquakes. By applying the inversion method to the present heights of the Genroku and Holocene marine terraces developed along the coasts of the southern Boso and Miura peninsulas, we estimated the fault slip distribution of the 1703 Genroku earthquake as follows. The source region extends along the Sagami trough from the Miura peninsula to the offing of the southern Boso peninsula, which covers the southern two thirds of the source region of the 1923 Kanto earthquake. The coseismic slip takes the maximum of 20 m at the southern tip of the Boso peninsula, and the moment magnitude (Mw) is calculated as 8.2. From the interseismic slip-deficit rates at the plate interface obtained by GPS data inversion, assuming that the total slip deficit is compensated by coseismic slip, we can roughly estimate the average recurrence interval as 350 years for large interplate events of any type and 1400 years for the Genroku-type events.
Glycosphingolipids (GSLs) are glycoconjugates that function as mediators of cell adhesion and modulators of signal transduction. Some well-defined markers of undifferentiated human embryonic stem ...cells (hESCs) and human induced pluripotent stem cells (hiPSCs) are glycoconjugates, such as SSEA-3, SSEA-4, TRA-1-60 and TRA-1-81. However, Comprehensive GSL profiles of hiPSCs have not yet been elucidated. The global images of GSLs from the parental cells, hiPSCs, and differentiated cells revealed that there are parental cell-independent specific glycolipids, including Globo H (fucosyl-Gb5Cer) and H type1 antigen (fucosyl-Lc4Cer) that are novel markers for undifferentiated hiPSCs. Interestingly, undifferentiated hiPSCs expressed H type 1 antigen, specific for blood type O, regardless of the cells' genotypes. Thus, in this study, we defined the dynamics of GSL remodeling during reprogramming from parental cell sets to iPSC sets and thence to iPSC-neural cells.
The assembly of amyloid ß protein (Aß) on ganglioside-enriched microdomains in presynaptic neuronal membranes is involved in the onset of Alzheimer’s disease. We previously found that a highly ...enriched ganglioside domain generated in a reconstituted lipid bilayer composed of synaptosomal lipids functioned as an Aß-sensitive ganglioside nanocluster (ASIGN) that may induce a spherical Aß assembly. In the present study, the major lipid components of a detergent-resistant membrane microdomain (DRM) fraction of synaptosomes prepared from an aged mouse brain were identified, and we demonstrate that the proportion of Aß-insensitive gangliosides such as GM3 directly affects the Aß assembly in synaptosomal membranes. Liquid chromatography coupled to mass spectrometry analyses indicated that ganglio a-series gangliosides (GM1, GM2, GM3, and GD1a) were abundant in DRM fractions. In addition, the GM3/GM1 ratio and the cholesterol content in the synaptosomal fraction differed from those in the non-synaptosomal fraction, in which GM1 and GM3 are sensitive and insensitive gangliosides, respectively. The highly enriched ganglioside nanocluster was identified by the surface topography of ternary mixed lipid bilayers composed of gangliosides, sphingomyelin, and cholesterol. Our results indicate that the composition of gangliosides is responsible for the characteristics of the nanocluster generated in the presynaptic neuronal membranes.
Objectives:
We evaluated the risk factors and outcomes of bone conduction (BC) hearing in cases of labyrinthine fistulas treated under the basic principle of complete removal of the cholesteatoma ...matrix.
Methods:
A total of 47 patients with labyrinthine fistulas were analyzed. The fistulas were classified into smaller (no more than 3 mm) and larger fistulas (more than 3 mm). The fistulas were classified by depth into 3 stages. Preoperative symptoms and postoperative results with special reference to BC hearing were analyzed.
Results:
Total preoperative loss of BC hearing was found in 3 of 36 ears (9%) in the smaller-fistula group and 4 of 11 ears (36%) in the larger-fistula group; this was a statistically significant difference. The BC hearing was preserved after operation in 30 of 31 ears (97%) in the smaller-fistula group and 5 of 7 ears (71%) in the larger-fistula group; this difference was also significant. The stage (depth) of the fistula did not correlate with the postoperative BC hearing.
Conclusions:
In smaller labyrinthine fistulas, complete removal of the cholesteatoma matrix can be relatively safely performed. However, in patients with larger fistulas, there is a potential for a complete loss of BC hearing.
Cofactor for acrosome reaction-inducing substance (Co-ARIS) is a steroidal saponin from the starfish Asterias amurensis. Saponins exist in many plants and few animals as self-defensive chemicals, but ...Co-ARIS has been identified as a cofactor for inducing the acrosome reaction (AR). In A. amurensis, the AR is induced by the cooperative action of egg coat components (ARIS, Co-ARIS, and asterosap); however, the mechanism of action of Co-ARIS is obscure. In this study we elucidated the membrane dynamics involved in the action of Co-ARIS. We found that cholesterol specifically inhibited the Co-ARIS activity for AR induction and detected the binding of labeled compounds with sperm using radioisotope-labeled Co-ARIS. Co-ARIS treatment did not reduce the content of sperm sterols, however, the condition was changed and localization of GM1 ganglioside on the periacrosomal region disappeared. We then developed a caveola-breaking assay, a novel method to detect the effect of chemicals on microdomains of culture cell, and confirmed the disturbance of somatic cell caveolae in the presence of Co-ARIS. Finally, by atomic force microscopy observations and surface plasmon resonance measurements using an artificial membrane, we revealed that Co-ARIS colocalized with GM1 clusters on the microdomains. Through this study, we revealed a capacitation-like event for AR in starfish sperm.
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The structures and amounts of glycosaminoglycan (GAG) produced by cells have attracted much interest because GAG biosynthesis activity can change in cellular processes such as disease and ...differentiation. β-Xylosides, also called saccharide primers, have been used as artificial acceptors not only to generate GAG oligosaccharides in cells and tissues but also to investigate their biosynthetic pathways. Various analytical methods have been applied to confirm the structure and amounts of GAG oligosaccharides elongated using saccharide primers, yet sample preparation processes such as solid-phase extraction in analysis can cause experimental error and disrupt accurate comparative quantification of glycosylated products. In this study, we developed a new quantification method using a deuterium-labeled saccharide primer. The “heavy” and “light” primers were chemically synthesized, and priming abilities were confirmed by liquid chromatography-tandem mass spectrometry. Relative peak areas of light/heavy products showed good linearity and were well correlated with the theoretical amounts of glycosylated products. Then, as a validation study, we carried out a biosynthesis inhibition assay using known GAG biosynthesis inhibitors. According to the relative quantification using saccharide primers, differences in the mode-of-action among the four GAG biosynthesis inhibitors were dependent on the GAG biosynthetic pathway. Our results indicate that the method will likely forge a new path for comparative glycosaminoglycomics using cultured cells and tissues.
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