189 research outputs found

    Dynamical Gauge Field induced by the Berry Phase Mechanism

    Full text link
    Some part of the local gauge symmetries in the low energy region, say, lower than GUT or the Planck energy can be an induced symmetry describable with the holonomy fields associated with a topologically non-trivial structure of partially compactified space. In the case where a six dimensional space is compactified by the Kaluza-Klein mechanism into a product of the four dimensional Minkowski space M4M_{4} and a two dimensional Riemann surface with the genus gg, Σg\Sigma_{g}, we show that, in a limit where the compactification mass scale is sent to infinity, a model lagrangian with a U(1) gauge symmetry produces the dynamical gauge fields in M4M_{4} with a product of gg U(1)'s symmetry, i.e., U(1)××\times \cdots\timesU(1). These fields are induced by a Berry phase mechanism, not by the Kaluza-Klein. The dynamical degrees of freedom of the induced fields are shown to come from the holonomies, or the solenoid potentials, associated with the cycles of Σg\Sigma_{g}. The production mechanism of kinetic energy terms for the induced fields are discussed in detail.Comment: 18 pages and 2 figures(available upon request), OU-HET 192, LaTeX fil

    Association between Total Antioxidant Capacity in Breast Milk and Postnatal Age in Days in Premature Infants

    Get PDF
    This study aimed to consider the significance of breast milk in preventing oxidative stress by comparing total antioxidant capacity (TAC) in breast milk and formula milk for premature infants, demonstrating the relationship between TAC in breast milk and postnatal age in days. We used the biological anti-oxidant potential test, a new method to measure TAC in breast milk. Breast milk for premature infants were stored at −20°C and thawed within 48 h of collection. We measured TAC in two types of formula milk in the same way. TAC was clearly higher in breast milk than formula milk. Although a negative correlation was observed between TAC in breast milk and age when collected, TAC was always higher than the average TAC in formula milk. TAC in breast milk is higher than TAC in formula milk. We suggest the importance of breast milk for preventing oxidative stress and starting breastfeeding early

    ATP-dependent reversible association of proteasomes with multiple protein components to form 26S complexes that degrade ubiquitinated proteins in human HL-60 cells

    Get PDF
    AbstractThe role of proteasomes in ubiquitin (Ub)-dependent protein degradation was studied by analyzing lysates of human promyelocytic leukemia HL-60 cells by glycerol density gradient centrifugation. High succinyl-Leu-Leu-Val-Tyr-4-methylcoumaryl-7-amide hydrolyzing activity was found in the 26S fraction, whereas the 20S fraction containing proteaomes had no activity. Addition of 0.05% sodium dodecylsulfate to the latter fraction, however, induced marked activity. The 26S, but not the 20S fraction catalyzed ATP-dependent degradation of [125I]lysozyme-Ub conjugate. Depletion from the lysate of ATP caused complete shift of the active 26S complex to the latent 20S form, whereas in the lysate prepared from ATP-depleted cells, ATP converted 20S proteasomes to 26S complexes. The immunoprecipitated 26S complexes were found to consist of proteasomes and 13–15 other proteins ranging in size from 35 to 110 kDa. We conclude that in the lysate, latent proteasomes undergo reversible, ATP-dependent association with multiple protein components to form 26S complexes that catalyze ATP-dependent degradation of Ub-protein conjugates

    Up-regulation of protein serine/threonine phosphatase type 2C during 1α,25-dihydroxyvitamin D3-induced monocytic differentiation of leukemic HL-60 cells

    Get PDF
    AbstractTreatment with 20 nM 1α,25-dihydroxyvitamin D3 (1,25(OH)2D3) caused a progressive increase in the activity of Mg2+-dependent protein serine/threonine phosphatase type 2C (PP2C) in subcellular fractions of HL-60 cells, whereas PP2C activity was relatively constant throughout all-trans retinoic acid-induced (1 μM) granulocytic differentiation. The increase in PP2C activity appeared to parallel the 1,25(OH)2D3-induced phenotypic and functional changes in HL-60 cells. Immunoblot and Northern blot analysis indicated that the increase in PP2C activity corresponded to the increased expression of PP2C protein, which was preceded by an increase in the level of mRNA for PP2Cβ. No mRNA for PP2Cα was detected in resting or 1,25(OH)2D3-stimulated HL-60 cells. These results suggest that the increased expression of PP2C is related with the 1,25(OH)2D3-induced monocytic differentiation of HL-60 cells

    cDNA cloning of rat proteasome subunit RC1, a homologue of RING10 located in the human MHC class II region

    Get PDF
    AbstractThe nucleotide sequence of a cDNA that encodes a new subunit, named RC1, of rat proteasomes (multicatalytic proteinase complexes) has been determined. The polypeptide predicted from the open reading frame consisted of 208 amino acid residues with a calculated molecular mass of 23,130, which is consistent with the size obtained by electrophoretic analysis of purified RC1. The partial amino acid sequences of several fragments of RC1, obtained by protein chemical analyses, were found to be in excellent accordance with those deduced from the cDNA sequence. Surprisingly, the overall structure of RC1 was found to be almost identical to that of recently isolated RING10, whose gene is located in the class II region of the human MHC gene cluster. This finding suggests that RC1 is a homologue of human RING10, supporting the proposal that proteasomes are involved in the antigen processing pathway

    Can CT colonography be useful for colon cancer screening?

    Get PDF
    For early detection and treatment of colon cancer, increasing of cancer screening rates is an urgent task. We started CT colonography(CTC)in September 2015 and have examined 309 cases for16months. CTC was found to be better tolerated by patients than conventional colonoscopy. Furthermore, lesions were efficiently detected by CTC. We make efforts to improve both the sensitivity and specificity of CTC and hope to reduce the mortality rate of colon cancer with popularization of CTC

    cDNA cloning and sequencing of component C5 of proteasomes from rat hepatoma cells

    Get PDF
    AbstractProteasomes are multicatalytic proteinase complexes consisting of a set of non-identical polypeptide subunits. A cDNA for component C5 of rat proteasomes was isolated by screening a Reuber H4TG hepatoma cell cDNA library using synthetic oligodeoxynucleotide probes corresponding to partial amino acid sequences of the protein. The polypeptide deduced from the open reading frame consisted of 240 amino acid residues with a calculated molecular weight of 26479. Computer analysis revealed little similarity of C5 to other proteins reported so far. The primary structure of C5 showed partial sequence homology to that of another component C3, but no regions of homology with the sequence of component C2. Thus C5 is concluded to be a new type of subunit of the proteasome complex
    corecore