Signaling via release of Ca2+ from intracellular stores is mediated by several systems, including the inositol 1,4,5-trisphosphate (IP3) and cADP-ribose (cADPR) pathway. We recently discovered a high ...capacity for cADPR synthesis in rat glomeruli and cultured mesangial cells (MC). We sought to determine whether 1) cADPR synthesis in MC is regulated by cytokines and hormones, 2) ryanodine receptors (RyRs) are expressed in MC, and 3) Ca2+ is released through RyRs in response to cADPR. We found that ADP-ribosyl cyclase, a CD38-like enzyme that catalyzes cADPR synthesis, is upregulated in MC by tumor necrosis factor-alpha, interleukin-1beta, and all-trans retinoic acid (atRA). 3Hryanodine binds to microsomal fractions from MC with high affinity in a Ca2+-dependent manner; binding is enhanced by specific RyR agonists and blocked by ruthenium red and cADPR. Western blot analysis confirmed the presence of RyR in MC. Release of 45Ca2+ from MC microsomes was stimulated by cADPR; release was blocked by ruthenium red and 8-bromo-cADPR. ADPR (non-cyclic) was without effect. In MC, TNF-alpha and atRA amplified the increment of cytoplasmic Ca2+ elicited by vasopressin. We conclude that MC possess elements of a novel ADP-ribosyl cyclase-->cADPR-->RyR-->Ca2+-release signaling pathway subject to regulation by proinflammatory cytokines and steroid superfamily hormones.
Nicotinic acid adenine dinucleotide phosphate (NAADP), a molecule derived from beta-NADP, has been shown to trigger Ca2+ release from intracellular stores of invertebrate eggs and mammalian cell ...microsomes. NAADP-induced Ca2+ release occurs through a mechanism distinct from that of inositol-1,4,5-trisphosphate- or cyclic ADP-ribose-elicited Ca2+ release. This study investigated whether NAADP can be synthesized in rat kidney. Extracts from glomeruli, mesangial cells, and papilla have high NAADP synthetic capacities. Conversely, synthesis of NAADP in kidney cortex was almost undetectable. Furthermore, 9-cis-retinoic acid significantly up-regulated NAADP synthesis in mesangial cells. Authenticity of NAADP biosynthesis in glomeruli was affirmed by HPLC analysis. NAADP stimulated Ca2+ release from mesangial cell microsomes through a pathway distinct from that of inositol-1,4,5-trisphosphate or cyclic ADP-ribose. NAADP-triggered Ca2+ release may play an important role in regulation of renal function.
Whether SiC\(_2\) is a parent species, that is formed in the photosphere or as a by-product of high-temperature dust formation, or a daughter species, formed in a chemistry driven by the ...photodestruction of parent species in the outer envelope, has been debated for a long time. Here, we analyze the ALMA observations of four SiC\(_2\) transitions in the CSEs of three C-rich AGB stars (AI Vol, II Lup, and RAFGL 4211), and found that SiC\(_2\) exhibits an annular, shell-like distribution in these targets, suggesting that SiC\(_2\) can be a daughter species in the CSEs of carbon-rich AGB stars. The results can provide important references for future chemical models.
TU83; To explore emission baseline, technically the most difficult issue for Clean Development Mechanism (CDM) project development, as well as to examine whether CDM is a possible way to help Beijing ...restructure its heating energy consumption, this paper conducts a CDM baseline case study on residential heating in Beijing. Based on investigation, energy consumption forecast and economic analysis of future technology options, the technology benchmark and site-specific baselines for both retrofit projects and new heating projects have been discussed. The results indicate that fuel switching from coal to natural gas can meet the additionality criteria in many cases and will be the main type of CDM project. In addition, it also proves that the technology benchmark and the case-by-case baseline setting approach are applicable for future CDM cooperation projects on heating in Beijing.
A New Computer Architecture Using a New Program Driving Method Xiaobo Li; Xiangdong Cui; Xiaoqiang Ni ...
5th IEEE/ACIS International Conference on Computer and Information Science and 1st IEEE/ACIS International Workshop on Component-Based Software Engineering,Software Architecture and Reuse (ICIS-COMSAR'06),
2006
Conference Proceeding
Much dependency among the instructions of one program often limits the parallelism that can be exploited. In the other hand, the dependency among the instructions from different programs is much ...smaller, and the parallelism is more easily achieved. However, traditional processors are all using "hardware PC+" to drive a program to run, which is unable to run more programs in a single kernel processor concurrently and is therefore unable to exploit the parallelism of instructions of programs. This paper proposes a new type of computer processor (called concurrent multiple program processor CMPP) architecture using a new program driving method which can run more than one program in a single kernel processor concurrently without using interrupt technique. The main idea of the new driving method is to pick up all the program/instruction driving elements/factors to form a driving vector, called program driving vector (PDV) or program driver (PD) for short, so that many PDs can drive many programs to run concurrently
Although dietary fish oil supplementation has been used to prevent the progression of kidney disease in patients with IgA nephropathy, relatively few studies provide a mechanistic rationale for its ...use. Using an antithymocyte (ATS) model of mesangial proliferative glomerulonephritis, we recently demonstrated that fish oil inhibits mesangial cell (MC) activation and proliferation, reduces proteinuria, and decreases histologic evidence of glomerular damage. We therefore sought to define potential mechanisms underlying the antiproliferative effect of docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), the predominant ω-3 polyunsaturated fatty acids found in fish oil, in cultured MC. DHA and EPA were administered to MC as bovine serum albumin fatty-acid complexes. Low-dose (10-50 μmol/L) DHA, but not EPA, inhibited basal and epidermal growth factor (EGF)–stimulated
3H-thymidine incorporation in MCs. At higher doses (100 μmol/L), EPA and DHA were equally effective in suppressing basal and EGF-stimulated MC mitogenesis. Low-dose DHA, but not EPA, decreased ERK activation by 30% (
P < .01), as assessed with Western-blot analysis using phosphospecific antibodies. JNK activity was increased by low-dose DHA but not by EPA. p38 activity was not significantly altered by DHA or EPA. Cyclin E activity, as assessed with a histone H1 kinase assay, was inhibited by low-dose DHA but not by EPA. DHA increased expression of the cell cycle inhibitor p21 but not p27; EPA had no effect on p21 or p27. We propose that the differential effect of low-dose DHA vs EPA in suppressing MC mitogenesis is related to down-regulation of ERK and cyclin E activity and to induction of p21.
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