The synthesis, spectroscopic characterization, and fluorescence quenching efficiency of polymers and copolymers containing tetraphenylsilole or tetraphenylgermole with Si-Si, Ge-Ge, and Si-Ge backbones are reported. Poly(tetraphenyl)germole, 2, was synthesized from the reduction of dichloro(tetraphenyl)germole with 2 equivs of Li. Silole-germole alternating copolymer 3 was synthesized by coupling dilithium salts of tetraphenylsilole dianion with dichloro(tetraphenyl)germole. Other tetraphenylmetallole-silane copolymers, 4-12, were synthesized through the Wurtz-type coupling of the dilithium salts of the tetraphenylmetallole dianion and corresponding dichloro(dialkyl)silanes. The molecular weights (M(w)) of these metallole-silane copolymers are in the range of 4000 approximately 6000. Detection of nitroaromatic molecules, such as nitrobenzene (NB), 2,4-dinitrotoluene (DNT), 2,4,6-trinitrotoluene (TNT), and picric acid (PA), has been explored. A linear Stern-Volmer relationship was observed for the first three analytes, but not for picric acid. Fluorescence spectra of polymetalloles or metallole-silane copolymers obtained in either toluene solutions or thin polymer films displayed no shift in the maximum of the emission wavelength. This suggests that the polymetalloles or metallole-silanes exhibit neither pi-stacking of polymer chains nor excimer formation. Fluorescence lifetimes of polymetalloles and metallole-silanes were measured both in the presence and absence of TNT, and tau(o)/tau is invariant. This requires that photoluminescence quenching occurs by a static mechanism.

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Not one, but two structurally distinct forms are obtained depending upon the crystallization temperature when Li2([PhC]4Ge) crystallizes from dioxane. In one form (left) the two lithium iòns are located on opposite sides of the germole rings each η5 coordinated to all of the ring atoms. In the other form (right), one lithium ion is η5 coordinated to the ring atoms and the other is η1 coordinated to the germanium center. The CC distances within the ring of the germole dianion are nearly equal, indicating that the bonding is highly delocalized.

Cancer is a very complicated process, characterized by the uncontrolled, unbalanced overgrowth of malignant cells. The complexity of oncogenic processes and cancer progressions has demanded the discovery of biomarkers with a high sensitivity and specificity for diagnosis, prognosis, diseases monitoring, and therapeutic response prediction. Unfortunately, a discrete biomarker for colon cancer has yet to be discovered, although nearly 800,000 new colorectal cancer cases are thought to globally occur each year, which account for ϳ10% of all incident cancers, and the mortality from colorectal cancer is estimated at nearly 450,000 per year (1). MLI1 and MSH genes are associated with hereditary non-polyposis colon cancer (2), and the APC gene is associated with familial adenomatous polyposis (3), but those factors fail to account for an occurrence of wide range of colon cancer. Moreover, colon cancer is one of the epithelium-derived cancers in which the circumstantial factors govern over hereditary genetic factors. These require a clear marker that serves as tracer molecule for the efficacious treatment of colon cancer.Recent proteomics have focused on a dynamic alteration of post-translational modification of proteins, and many lines of evidence indicate that changes in post-translational modification of proteins are closely associated with the pathogenic processes of cells. An aberrant glycosylation induced by Nacetylglucosaminyltransferase V (GnT-V), 1 is a representative example of such protein modification as is implicated in tumor progression. An increase in ␤1,6-branching on N-linked glycans is associated with metastatic potential of cancer cells (4). Several target molecules for GnT-V were proposed to be involved in cancer progressions, including matriptase (5), ␤ 1 integrin (6), and N-cadherin (7). However, those proteins are membrane-bound proteins and were not demonstrated to be aberrantly glycosylated in sera or tissues of cancer patients. Recent work stresses the discrete roles of the microenviron-

To define whether individual human leukocyte antigen (HLA) class I allotypes are used preferentially in human cytomegalovirus (CMV)-specific cytotoxic T lymphocyte responses, CD8+ T cell responses restricted by up to six HLA class I allotypes in an individual were measured in parallel using K562-based artificial antigen-presenting cells expressing both CMV pp65 antigen and one of 32 HLA class I allotypes (7 HLA-A, 14 HLA-B, and 11 HLA-C) present in 50 healthy Korean donors. The CD8+ T cell responses to pp65 in the HLA-C allotypes were lower than responses to those in HLA-A and -B allotypes and there was no difference between the HLA-A and HLA-B loci. HLA-A*02:01, -B*07:02, and -C*08:01 showed the highest magnitude and frequency of immune responses to pp65 at each HLA class I locus. However, HLA-A*02:07, -B*59:01, -B*58:01, -B*15:11, -C*03:02, and -C*02:02 did not show any immune responses. Although each individual has up to six different HLA allotypes, 46% of the donors showed one allotype, 24% showed two allotypes, and 2% showed three allotypes that responded to pp65. Interestingly, the frequencies of HLA-A alleles were significantly correlated with the positivity of specific allotypes. Our results demonstrate that specific HLA class I allotypes are preferentially used in the CD8+ T cell immune response to pp65 and that a hierarchy among HLA class I allotypes is present in an individual.

Gangliosides abundant in the nervous system have been implicated in a broad range of biological functions, including the regulation of cell proliferation and death. Glutamate-induced cell death, which is accompanied by an accumulation of reactive oxygen species (ROS), is a major contributor to pathological cell death within the nervous system. However, the mechanism underlying this neuronal cell death has not been fully elucidated. In this study, we report that ganglioside GM3 is involved in neuronal cell death. GM3 was up-regulated in the mouse hippocampal cell line HT22 death caused by glutamate. Increment in GM3 levels by both the exogenous addition of GM3 and the overexpression of the GM3 synthase gene induced neuronal cell death. Overexpression of GM3 synthase by microinjecting mRNA into zebrafish embryos resulted in neuronal cell death in the central nervous system (CNS). Conversely, RNA interference-mediated silencing of GM3 synthase rescued glutamate-induced neuronal death, as evidenced by the inhibition of massive ROS production and intracellular calcium ion influx. 12-lipoxygenase (12-lipoxygenase) (12-LOX) was recruited to glycosphingolipid-enriched microdomains (GEM) in a GM3-dependent manner during oxidative glutamate toxicity. Our findings suggest that GM3 acts as not only a mediator of oxidative HT22 death by glutamate but also a modulator of in vivo neuronal cell death.