An initial biochemical and cell biological characterization of the mammalian homologue of a central plant developmental switch, COP1

BACKGROUND: Constitutive photomorphogenic 1 (COP1) has been defined as a central regulator of photomorphogenic development in plants, which targets key transcription factors for proteasome-dependent degradation. Although COP1 mammalian homologue has been previously reported, its function and distribution in animal kingdom are not known. RESULTS: Here we report the characterization of full-length human and mouse COP1 cDNAs and the genomic structures of the COP1 genes from several different species. Mammalian COP1 protein binds to ubiquitinated proteins in vivo and is itself ubiquitinated. Furthermore, mammalian COP1 is predominately nuclear localized and exists primarily as a complex of over 700 kDa. Through mutagenesis studies, we have defined a leucine-rich nuclear export signal (NES) within the coiled-coil domain of mammalian COP1 and a nuclear localization signal (NLS), which is composed of two clusters of positive-charged amino acids, bridged by the RING finger. Disruption of the RING finger structure abolishes the nuclear import, while deletion of the entire RING finger restores the nuclear import. CONCLUSIONS: Our data suggest that mammalian COP1, similar to its plant homologue, may play a role in ubiquitination. Mammalian COP1 contains a classic leucine-rich NES and a novel bipartite NLS bridged by a RING finger domain. We propose a working model in which the COP1 RING finger functions as a structural scaffold to bring two clusters of positive-charged residues within spatial proximity to mimic a bipartite NLS. Therefore, in addition to its well-characterized role in ubiquitination, the RING finger domain may also play a structural role in nuclear import

The Researches on the Mobile E-Business Implements and Mode in Small and Medium-sized Enterprise

The “mobile e-business” is a business activity derived out by the concept of the “e-business”, which can finish the specific commercial service function through mobile devices, such as cell-phone, PDA, etc, with the marketing purpose of achieving products and service. Mobile e-business is gradually known by kinds of enterprises, and successively put into practice among them. This paper sets out from analyzing the prospect of mobile e-business and current situation of small and medium-sized enterprise of our country, proposes the technology, implementation means, mode of the mobile e-business for the small and medium-sized enterprise, and compared with the application mode of the large-scale company with its one\u27s own characteristic

Ameliorative Effect and Underlying Mechanisms of Total Triterpenoids from Psidium guajava Linn (Myrtaceae) Leaf on High-Fat Streptozotocin-induced Diabetic Peripheral Neuropathy in Rats

Purpose: To investigate whether the total triterpenoids extracted from Psidium Guajava leaves (TTPGL) attenuate the development of diabetic peripheral neuropathy in rats by regulating the NF-κB pathway of the inflammatory process and its signaling mediators.Methods: All the Sprague Dawley rats used were maintained in a clean environment on a 12 h light/12h dark cycle. High-fat feeding and intraperitoneal injection of 40 mg/kg streptozotocin (STZ) were used to induce diabetes in the rats. The rats were randomly divided into 5 groups: diabetic mellitus (DM) group; TTPGL - 30 group, TTPGL - 60 group and TTPGL - 120 group treated by intragastric administration (i.g) with 30, 100 and 120 mg/kg/day TTPGL, respectively. The well-established drug, rosiglitazone (RSG, 3 mg/k/d, i.g.), was used as positive control. Normal rats served as control group. Nerve conduction velocity and sensitive tests were measured on weeks 1, 4 and 8. After 8 weeks administration, expression of pro-inflammatory molecules (TNF - α, IL - 6 and iNOS) and tissue proteins (Akt, IKKα, and NF – κB - p65) were evaluated to assess biochemical changes.Results: Compared to DM group, TTPGL (especially 120 mg / kg dose) treatment improved (p < 0.05) physical functions and provided neuronal protection in high - fat/streptozotocin - induced peripheral neuropathy rats. We found that the expressions of several pro - inflammatory factors such as tumor necrosis factor - α (TNF - α), IL - 6 and inducible nitric oxide synthase (iNOS) were highly suppressed (p < 0.05 or p < 0.01) by TTPGL in sciatic nerve. Mechanism analysis indicated that the ameliorative effect of TTPGL, in part, is through suppression of the expression of pro - inflammatory cytokines by NF - κB pathway mediation.Conclusion: TTPGL offers a potential therapeutic approach for the treatment of diabetic peripheral neuropathy.Keywords: Triterpenoids, Psidium Guajava, Diabetic peripheral neuropathy, Pro inflammatory cytokines, NF-κB pathwa

Bibliometric evaluation of research on political risks in construction projects

The current study aims to provide an overview of the research on political risk using the Web of Science（WoS）database as well as summarize research results and put forward some suggestions for research directions of political risk in international construction projects. It is the first time scientometric analysis of political risk research is executed. In this regard, the papers related to political risk in the WoS database have been retrieved and the literature is sorted out by visual and content analysis methods. Visual analysis is used to analyze the research overview, knowledge base, and research hotspots of this field. The content analysis method is adopted to expound the current research focus from three perspectives inducing the influence of political risk, risk assessment, and risk management measures. The results show that in the political risk context, the number of publications has experienced an increasing trend in recent years. Based on the existing literature on political risk for all companies, this overview provides some suggestions to address the political risk in international construction projects in the future. The results contribute to the scholars understanding of the research overview, research hotspots, and future research directions of political risk research in construction projects

Naringenin prevents TGF-β1 secretion from breast cancer and suppresses pulmonary metastasis by inhibiting PKC activation

Presenting the incidence of pulmonary metastasis (mice with metastasis/total mice). Tumor-bearing mice treated with naringenin or 1D11 were imaged on day 24 using bags to avoid the bioluminescence from primary tumor. The mice with pulmonary metastases were numbered based on the bioluminescence signal. (TIF 26 kb

Effect of diesel detergent synergists on VOCs emissions from engine

In this study, the volatile organic compounds (VOCs) emissions from engine fueled diesel with and without detergent synergist were measured by gas chromatography mass spectrometry(GC-MS). The test results show that compared with reference diesel fuel (without diesel detergent synergist), the use of different diesel detergent synergists has different effects on the VOCs emissions while without after-treatment device. Whether with or without after-treatment device, alkanes always account for the highest proportion of VOCs emissions while engine fuels with different diesel detergent synergists. After-treatment device diesel oxidation catalyst coupled with diesel particulate filter (DOC+DPF) has high catalytic efficiency for VOCs emissions from engine fueled with different fuels, and most of the catalytic efficiency could reach more than 95%. With the catalytic treatment of after-treatment device,the concentrations of carcinogens (detected in this study) in VOCs emissions from engine fueled with and without detergent synergist are far lower than that specified in reference standard GBZ 2.1-2007 “Occupational Exposure Limits for Hazardous Factors in the Workplace and Chemical Hazardous Factors”, respectively. The test results indicate that the use of diesel detergent synergist will not have an adverse impact on human health and it can be safely used