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Sample records for c-flip degradation mediates

  1. Quercetin sensitizes pancreatic cancer cells to TRAIL-induced apoptosis through JNK-mediated cFLIP turnover.

    Science.gov (United States)

    Kim, Ji Hye; Kim, Min Joo; Choi, Kyung-Chul; Son, Jaekyoung

    2016-09-01

    Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is a promising anticancer agent that can selectively kill cancer cells. Nonetheless, many cancers are resistant to TRAIL, and the molecular mechanisms of TRAIL resistance in cancer, particularly pancreatic cancer, are still unclear. In this study, we tested the hypothesis that quercetin, a flavonoid, induces apoptosis in TRAIL-resistant pancreatic cancer cells. Although quercetin alone had no significant cytotoxic effect, when combined with TRAIL, it promoted TRAIL-induced apoptosis that required mitochondrial outer membrane permeabilization. A BH3-only protein BID knockdown dramatically attenuated TRAIL/quercetin-induced apoptosis. The expression levels of cellular FLICE-like inhibitory protein (cFLIP) decreased in a dose-dependent manner in the presence of quercetin, and overexpression of cFLIP was able to robustly rescue pancreatic cancer cells from TRAIL/quercetin-induced apoptosis. Additionally, quercetin activated c-Jun N-terminal kinase (JNK) in a dose-dependent manner, which in turn induced the proteasomal degradation of cFLIP, and JNK activation also sensitized pancreatic cancer cells to TRAIL-induced apoptosis. Thus, our results suggest that quercetin induces TRAIL-induced apoptosis via JNK activation-mediated cFLIP turnover. PMID:27477310

  2. Inhibition of methyltransferases accelerates degradation of cFLIP and sensitizes B-cell lymphoma cells to TRAIL-induced apoptosis.

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    Frank K Braun

    Full Text Available Non-Hodgkin lymphomas (NHLs are characterized by specific abnormalities that alter cell cycle regulation, DNA damage response, and apoptotic signaling. It is believed that cancer cells are particularly sensitive to cell death induced by tumor necrosis factor α-related apoptosis-inducing ligand (TRAIL. However, many cancer cells show blocked TRAIL signaling due to up-regulated expression of anti-apoptotic factors, such as cFLIP. This hurdle to TRAIL's tumor cytotoxicity might be overcome by combining TRAIL-based therapy with drugs that reverse blockages of its apoptotic signaling. In this study, we investigated the impact of a pan-methyltransferase inhibitor (3-deazaneplanocin A, or DZNep on TRAIL-induced apoptosis in aggressive B-cell NHLs: mantle cell, Burkitt, and diffuse large B-cell lymphomas. We characterized TRAIL apoptosis regulation and caspase activation in several NHL-derived cell lines pre-treated with DZNep. We found that DZNep increased cancer cell sensitivity to TRAIL signaling by promoting caspase-8 processing through accelerated cFLIP degradation. No change in cFLIP mRNA level indicated independence of promoter methylation alterations in methyltransferase activity induced by DZNep profoundly affected cFLIP mRNA stability and protein stability. This appears to be in part through increased levels of cFLIP-targeting microRNAs (miR-512-3p and miR-346. However, additional microRNAs and cFLIP-regulating mechanisms appear to be involved in DZNep-mediated enhanced response to extrinsic apoptotic stimuli. The capacity of DZNep to target cFLIP expression on multiple levels underscores DZNep's potential in TRAIL-based therapies for B-cell NHLs.

  3. Withanolide E sensitizes renal carcinoma cells to TRAIL-induced apoptosis by increasing cFLIP degradation.

    Science.gov (United States)

    Henrich, C J; Brooks, A D; Erickson, K L; Thomas, C L; Bokesch, H R; Tewary, P; Thompson, C R; Pompei, R J; Gustafson, K R; McMahon, J B; Sayers, T J

    2015-01-01

    Withanolide E, a steroidal lactone from Physalis peruviana, was found to be highly active for sensitizing renal carcinoma cells and a number of other human cancer cells to tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-mediated apoptosis. Withanolide E, the most potent and least toxic of five TRAIL-sensitizing withanolides identified, enhanced death receptor-mediated apoptotic signaling by a rapid decline in the levels of cFLIP proteins. Other mechanisms by which TRAIL sensitizers have been reported to work: generation of reactive oxygen species (ROS), changes in pro-and antiapoptotic protein expression, death receptor upregulation, activation of intrinsic (mitochondrial) apoptotic pathways, ER stress, and proteasomal inhibition proved to be irrelevant to withanolide E activity. Loss of cFLIP proteins was not due to changes in expression, but rather destabilization and/or aggregation, suggesting impairment of chaperone proteins leading to degradation. Indeed, withanolide E treatment altered the stability of a number of HSP90 client proteins, but with greater apparent specificity than the well-known HSP90 inhibitor geldanamycin. As cFLIP has been reported to be an HSP90 client, this provides a potentially novel mechanism for sensitizing cells to TRAIL. Sensitization of human renal carcinoma cells to TRAIL-induced apoptosis by withanolide E and its lack of toxicity were confirmed in animal studies. Owing to its novel activity, withanolide E is a promising reagent for the analysis of mechanisms of TRAIL resistance, for understanding HSP90 function, and for further therapeutic development. In marked contrast to bortezomib, among the best currently available TRAIL sensitizers, withanolide E's more specific mechanism of action suggests minimal toxic side effects. PMID:25719250

  4. FLIP the Switch: Regulation of Apoptosis and Necroptosis by cFLIP

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    Yuichi Tsuchiya; Osamu Nakabayashi; Hiroyasu Nakano

    2015-01-01

    cFLIP (cellular FLICE-like inhibitory protein) is structurally related to caspase-8 but lacks proteolytic activity due to multiple amino acid substitutions of catalytically important residues. cFLIP protein is evolutionarily conserved and expressed as three functionally different isoforms in humans (cFLIPL, cFLIPS, and cFLIPR). cFLIP controls not only the classical death receptor-mediated extrinsic apoptosis pathway, but also the non-conventional pattern recognition receptor-dependent apoptot...

  5. Targeting the Anti-Apoptotic Protein c-FLIP for Cancer Therapy

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    Safa, Ahmad R., E-mail: asafa@iupui.edu [Department of Pharmacology and Toxicology, Indiana University School of Medicine, 980 W. Walnut Street, R3-C524, Indianapolis, IN 46202 (United States); Indiana University Simon Cancer Center, Indiana University School of Medicine, 980 W. Walnut Street, R3-C524, Indianapolis, IN 46202 (United States); Pollok, Karen E. [Department of Pharmacology and Toxicology, Indiana University School of Medicine, 980 W. Walnut Street, R3-C524, Indianapolis, IN 46202 (United States); Indiana University Simon Cancer Center, Indiana University School of Medicine, 980 W. Walnut Street, R3-C524, Indianapolis, IN 46202 (United States); Herman B. Wells Center for Pediatric Research, 980 W. Walnut Street, R3-C524, Indianapolis, IN 46202 (United States)

    2011-03-29

    Cellular FLICE (FADD-like IL-1beta-converting enzyme)-inhibitory protein (c-FLIP) is a major resistance factor and critical anti-apoptotic regulator that inhibits tumor necrosis factor-alpha (TNF-alpha), Fas-L, and TNF-related apoptosis-inducing ligand (TRAIL)-induced apoptosis as well as chemotherapy-triggered apoptosis in malignant cells. c-FLIP is expressed as long (c-FLIP{sub L}), short (c-FLIP{sub S}), and c-FLIP{sub R} splice variants in human cells. c-FLIP binds to FADD and/or caspase-8 or -10 in a ligand-dependent and-independent fashion, which in turn prevents death-inducing signaling complex (DISC) formation and subsequent activation of the caspase cascade. Moreover, c-FLIP{sub L} and c-FLIP{sub S} are known to have multifunctional roles in various signaling pathways, as well as activating and/or upregulating several cytoprotective signaling molecules. Upregulation of c-FLIP has been found in various tumor types, and its downregulation has been shown to restore apoptosis triggered by cytokines and various chemotherapeutic agents. Hence, c-FLIP is an important target for cancer therapy. For example, small interfering RNAs (siRNAs) that specifically knockdown the expression of c-FLIP{sub L} in diverse human cancer cell lines augmented TRAIL-induced DISC recruitment and increased the efficacy of chemotherapeutic agents, thereby enhancing effector caspase stimulation and apoptosis. Moreover, small molecules causing degradation of c-FLIP as well as decreasing mRNA and protein levels of c-FLIP{sub L} and c-FLIP{sub S} splice variants have been found, and efforts are underway to develop other c-FLIP-targeted cancer therapies. This review focuses on (1) the functional role of c-FLIP splice variants in preventing apoptosis and inducing cytokine and drug resistance; (2) the molecular mechanisms that regulate c-FLIP expression; and (3) strategies to inhibit c-FLIP expression and function.

  6. FLIP the Switch: Regulation of Apoptosis and Necroptosis by cFLIP

    Directory of Open Access Journals (Sweden)

    Yuichi Tsuchiya

    2015-12-01

    Full Text Available cFLIP (cellular FLICE-like inhibitory protein is structurally related to caspase-8 but lacks proteolytic activity due to multiple amino acid substitutions of catalytically important residues. cFLIP protein is evolutionarily conserved and expressed as three functionally different isoforms in humans (cFLIPL, cFLIPS, and cFLIPR. cFLIP controls not only the classical death receptor-mediated extrinsic apoptosis pathway, but also the non-conventional pattern recognition receptor-dependent apoptotic pathway. In addition, cFLIP regulates the formation of the death receptor-independent apoptotic platform named the ripoptosome. Moreover, recent studies have revealed that cFLIP is also involved in a non-apoptotic cell death pathway known as programmed necrosis or necroptosis. These functions of cFLIP are strictly controlled in an isoform-, concentration- and tissue-specific manner, and the ubiquitin-proteasome system plays an important role in regulating the stability of cFLIP. In this review, we summarize the current scientific findings from biochemical analyses, cell biological studies, mathematical modeling, and gene-manipulated mice models to illustrate the critical role of cFLIP as a switch to determine the destiny of cells among survival, apoptosis, and necroptosis.

  7. siRNA沉默c-FLIP对K562/ADR耐药性的影响%Effect of siRNA-mediated silencing of c-FLIP on adriamycin-resistance of K562/ADR cells

    Institute of Scientific and Technical Information of China (English)

    宋敏; 王建宁; 孟庆齐; 包红雨; 杨杰

    2015-01-01

    目的:探讨c-FLIP siRNA干扰c-FLIP mRNA水平对阿霉素耐药细胞K562/ADR的耐药性的影响及作用机制。方法应用siRNA干扰的方法抑制K562及K562/ADR细胞c-FLIP的表达,通过荧光定量PCR的方法检测c-FLIP mRNA表达及对多药耐药基因MDR1 mRNA水平的影响。MTT法检测c-FLIP干扰与否对K562及K562/ADR细胞增殖的影响,Annexin V/7-ADD双染研究c-FLIP干扰与否对K562及K562/ADR细胞凋亡的影响。结果与阴性siRNA转染组相比较,c-FLIP siRNA转染下调K562细胞中c-FLIP的mRNA后,K562细胞增殖受到一定程度的抑制(P<0.05),但是并未显著诱导细胞凋亡,c-FLIP干扰与否K562细胞48 h增殖率分别为(69.14±1.82)%和(60.69±2.23)%,凋亡率分别为(1.7±0.3)%和(1.8±0.2)%。与阴性siRNA转染组相比较, c-FLIP siRNA转染抑制K562/ADR细胞中c-FLIP的mRNA后,K562/ADR细胞增殖显著被抑制(P<0.05),并显著诱导了细胞凋亡增加(P<0.05),c-FLIP干扰与否K562/ADR细胞48 h增殖率分别为(-6.07±0.71)%和(-37.45±3.53)%,凋亡率分别为(5.2±0.4)%和(9.2±0.4)%。并且c-FLIP siRNA下调c-FLIP mRNA水平后,K562/ADR细胞中的多药耐药基因MDR1的mRNA表达水平也被显著下调(P<0.05)。结论 c-FLIP siRNA下调K562/ADR细胞中c-FLIP的mRNA水平抑制了多药耐药基因MDR1的表达,从而抑制了K562/ADR细胞对阿霉素的耐药性。%Objective To investigate the effect of silenced c-FLIP mRNA level by small interfering RNA (siRNA) on adriamycin-resistance of K562/ADR cells. Methods c-FLIP siRNA and negative siRNA were transfect-ed into K562 and K562/ADR cell lines respectively, and mRNA expression of c-FLIP and multi-drug resistance gene 1 (MDR1) were detected by quantitative PCR. Cell proliferation rate was detected by MTT assay, and cell apoptosis rate was assayed by Annexin V/7-ADD double-staining method. Results Compared with negative siRNA transfection group, siRNA transfection significantly decreased c-FLIP m

  8. The role of c-FLIP splice variants in urothelial tumours.

    OpenAIRE

    Ewald, F.; Ueffing, N; Brockmann, L; Hader, C; Telieps, T.; Schuster, M; Schulz, W A; Schmitz, I

    2011-01-01

    Deregulation of apoptosis is common in cancer and is often caused by overexpression of anti-apoptotic proteins in tumour cells. One important regulator of apoptosis is the cellular FLICE-inhibitory protein (c-FLIP), which is overexpressed, for example, in melanoma and Hodgkin's lymphoma cells. Here, we addressed the question whether deregulated c-FLIP expression in urothelial carcinoma impinges on the ability of death ligands to induce apoptosis. In particular, we investigated the role of the...

  9. Predisposition to apoptosis in keratin 8-null liver is related to inactivation of NF-κB and SAPKs but not decreased c-Flip

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    Jongeun Lee

    2013-05-01

    Keratin 8 and 18 (K8/K18 are major intermediate filament proteins of liver hepatocytes. They provide mechanical and nonmechanical stability, thereby protecting cells from stress. Hence, K8-null mice are highly sensitive to Fas-mediated liver cell apoptosis. However, the role of c-Flip protein in K8-null related susceptibility to liver injury is controversial. Here we analyzed c-Flip protein expression in various K8 or K18 null/mutant transgenic livers and show that they are similar in all analyzed transgenic livers and that previously reported c-Flip protein changes are due to antibody cross-reaction with mouse K18. Furthermore, analysis of various apoptosis- or cell survival-related proteins demonstrated that inhibition of phosphorylation of NF-κB and various stress activated protein kinases (SAPKs, such as p38 MAPK, p44/42 MAPK and JNK1/2, is related to the higher sensitivity of K8-null hepatocytes whose nuclear NF-κB is rapidly depleted through Fas-mediated apoptosis. Notably, we found that NF-κB and the studied protein kinases are associated with the K8/K18 complex and are released upon phosphorylation. Therefore, interaction of keratins with cell survival-related protein kinases and transcription factors is another important factor for hepatocyte survival.

  10. c-FLIP在凋亡增殖中的双向调节作用及与肿瘤预后和治疗关系的研究%Research progress on the dual regulation of c-FLIP in apoptosis and proliferation and the relationship between c-FLIP and tumor prognosis, chemotherapy, and TRAIL treatment in cancers

    Institute of Scientific and Technical Information of China (English)

    臧凤琳(综述); 孙保存(审校)

    2013-01-01

    细胞型Fas相关死亡域样白介素-1β转换酶抑制蛋白(c-FLIP)在细胞凋亡和增殖信号通路中具有重要的调节作用。一方面通过与Caspase-8竞争性结合上游信号阻断凋亡通路,另一方面经酶切释放出p43-FLIP和p22-FLIP片段促进NF-κΒ、Erk等增殖信号通路,最终引发肿瘤发生发展、浸润转移。c-FLIP的双向调节作用与蛋白表达量、底物的亲和力和亚细胞定位密切相关。恶性肿瘤中c-FLIP高表达使细胞逃逸机体免疫监视、耐受化疗药物杀伤以及抵抗TRAIL、FasL诱导的凋亡。本文初步阐释c-FLIP在不同的细胞微环境中对凋亡-增殖通路的双向调节作用及其分子机制,并对c-FLIP与恶性肿瘤预后、化疗和TRAIL生物治疗相关性进行综述,为肿瘤化疗耐药和TRAIL抵抗提供理论基础。%Cellular Fas-associated death domain-like interleukin-1β-converting enzyme inhibitory protein (c-FLIP) belongs to the death effector domain superfamily, which is important in regulating apoptosis and proliferation. c-FLIP inhibits the extrinsic recep-tor-mediated apoptotic pathways and intrinsic mitochondrial apoptotic pathways through competition with caspase-8 for recruitment to Fas-associated death domain protein. Moreover, the cleavage products (i.e., p43-FLIP fragment and p22-FLIP fragment) directly acti-vate NF-κΒ, Erk survival signaling, and other non-apoptotic signaling pathways. The c-FLIP (L) can function either as an anti-apoptotic molecule, in a way analogous to c-FLIP (S) and c-FLIP (R), or as a pro-apoptotic molecule to facilitate the activation of caspase-8 at the death-induced signaling complex. The identified dual functionality of c-FLIP depends on various factors, including its expression level, interaction with caspase-8, and its subcellular localization. c-FLIP is frequently over-expressed in many different tumor types, and con-tributes to tumor cell immune surveillance, chemotherapy resistance, and

  11. Hydrogen peroxide mediates higher order chromatin degradation.

    Science.gov (United States)

    Bai, H; Konat, G W

    2003-01-01

    Although a large body of evidence supports a causative link between oxidative stress and neurodegeneration, the mechanisms are still elusive. We have recently demonstrated that hydrogen peroxide (H(2)O(2)), the major mediator of oxidative stress triggers higher order chromatin degradation (HOCD), i.e. excision of chromatin loops at the matrix attachment regions (MARs). The present study was designed to determine the specificity of H(2)O(2) in respect to HOCD induction. Rat glioma C6 cells were exposed to H(2)O(2) and other oxidants, and the fragmentation of genomic DNA was assessed by field inversion gel electrophoresis (FIGE). S1 digestion before FIGE was used to detect single strand fragmentation. The exposure of C6 cells to H(2)O(2) induced a rapid and extensive HOCD. Thus, within 30 min, total chromatin was single strandedly digested into 50 kb fragments. Evident HOCD was elicited by H(2)O(2) at concentrations as low as 5 micro M. HOCD was mostly reversible during 4-8h following the removal of H(2)O(2) from the medium indicating an efficient relegation of the chromatin fragments. No HOCD was induced by H(2)O(2) in isolated nuclei indicating that HOCD-endonuclease is activated indirectly by cytoplasmic signal pathways triggered by H(2)O(2). The exposure of cells to a synthetic peroxide, i.e. tert-butyrylhydroperoxide (tBH) also induced HOCD, but to a lesser extent than H(2)O(2). Contrary to the peroxides, the exposure of cells to equitoxic concentration of hypochlorite and spermine NONOate, a nitric oxide generator, failed to induce rapid HOCD. These results indicate that rapid HOCD is not a result of oxidative stress per se, but is rather triggered by signaling cascades initiated specifically by H(2)O(2). Furthermore, the rapid and extensive HOCD was observed in several rat and human cell lines challenged with H(2)O(2), indicating that the process is not restricted to glial cells, but rather represents a general response of cells to H(2)O(2). PMID:12421592

  12. β-Elemene piperazine derivatives induce apoptosis in human leukemia cells through downregulation of c-FLIP and generation of ROS.

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    Zhiying Yu

    Full Text Available β-Elemene is an active component of the herb medicine Curcuma Wenyujin with reported antitumor activity. To improve its antitumor ability, five novel piperazine derivatives of β-elemene, 13-(3-methyl-1-piperazinyl-β-elemene (DX1, 13-(cis-3,5-dimethyl-1-piperazinyl-β-elemene (DX2, 13-(4-ethyl-1-piperazinyl-β-elemene (DX3, 13-(4-isopropyl-1-piperazinyl-β-elemene (DX4 and 13-piperazinyl-β-elemene (DX5, were synthesized. The antiproliferative and apoptotic effects of these derivatives were determined in human leukemia HL-60, NB4, K562 and HP100-1 cells. DX1, DX2 and DX5, which contain a secondary amino moiety, were more active in inhibiting cell growth and in inducing apoptosis than DX3 and DX4. The apoptosis induction ability of DX1 was associated with the generation of hydrogen peroxide (H(2O(2, a decrease of mitochondrial membrane potential (MMP, and the activation of caspase-8. Pretreatment with the antioxidants N-acetylcysteine and catalase completely blocked DX1-induced H(2O(2 production, but only partially its activation of caspase-8 and induction of apoptosis. HL-60 cells were more sensitive than its H(2O(2-resistant subclone HP100-1 cells to DX1-induced apoptosis. The activation of caspase-8 by these compounds was correlated with the decrease in the levels of cellular FLICE-inhibitory protein (c-FLIP. The proteasome inhibitor MG-132 augmented the decrease in c-FLIP levels and apoptosis induced by these derivatives. FADD- and caspase-8-deficient Jurkat subclones have a decreased response to DX1-induced apoptosis. Our data indicate that these novel β-elemene piperazine derivatives induce apoptosis through the decrease in c-FLIP levels and the production of H(2O(2 which leads to activation of both death receptor- and mitochondrial-mediated apoptotic pathways.

  13. Degradation of AF1Q by chaperone-mediated autophagy

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    Li, Peng; Ji, Min; Lu, Fei; Zhang, Jingru [Department of Hematology, Key Laboratory of Cardiovascular Remodeling and Function Research, Qilu Hospital, Shandong University, Jinan 250012 (China); Li, Huanjie; Cui, Taixing; Li Wang, Xing [Research Center for Cell Therapy, Key Laboratory of Cardiovascular Remodeling and Function Research, Qilu Hospital, Shandong University, Jinan 250012 (China); Tang, Dongqi, E-mail: tangdq@sdu.edu.cn [Research Center for Cell Therapy, Key Laboratory of Cardiovascular Remodeling and Function Research, Qilu Hospital, Shandong University, Jinan 250012 (China); Center for Stem Cell and Regenerative Medicine, The Second Hospital of Shandong University, Jinan 250033 (China); Ji, Chunyan, E-mail: jichunyan@sdu.edu.cn [Department of Hematology, Key Laboratory of Cardiovascular Remodeling and Function Research, Qilu Hospital, Shandong University, Jinan 250012 (China)

    2014-09-10

    AF1Q, a mixed lineage leukemia gene fusion partner, is identified as a poor prognostic biomarker for pediatric acute myeloid leukemia (AML), adult AML with normal cytogenetic and adult myelodysplastic syndrome. AF1Q is highly regulated during hematopoietic progenitor differentiation and development but its regulatory mechanism has not been defined clearly. In the present study, we used pharmacological and genetic approaches to influence chaperone-mediated autophagy (CMA) and explored the degradation mechanism of AF1Q. Pharmacological inhibitors of lysosomal degradation, such as chloroquine, increased AF1Q levels, whereas activators of CMA, including 6-aminonicotinamide and nutrient starvation, decreased AF1Q levels. AF1Q interacts with HSPA8 and LAMP-2A, which are core components of the CMA machinery. Knockdown of HSPA8 or LAMP-2A increased AF1Q protein levels, whereas overexpression showed the opposite effect. Using an amino acid deletion AF1Q mutation plasmid, we identified that AF1Q had a KFERQ-like motif which was recognized by HSPA8 for CMA-dependent proteolysis. In conclusion, we demonstrate for the first time that AF1Q can be degraded in lysosomes by CMA. - Highlights: • Chaperone-mediated autophagy (CMA) is involved in the degradation of AF1Q. • Macroautophagy does not contribute to the AF1Q degradation. • AF1Q has a KFERQ-like motif that is recognized by CMA core components.

  14. Cardiomyocyte ryanodine receptor degradation by chaperone-mediated autophagy

    Science.gov (United States)

    Pedrozo, Zully; Torrealba, Natalia; Fernández, Carolina; Gatica, Damian; Toro, Barbra; Quiroga, Clara; Rodriguez, Andrea E.; Sanchez, Gina; Gillette, Thomas G.; Hill, Joseph A.; Donoso, Paulina; Lavandero, Sergio

    2013-01-01

    Time for primary review: 15 days Aims Chaperone-mediated autophagy (CMA) is a selective mechanism for the degradation of soluble cytosolic proteins bearing the sequence KFERQ. These proteins are targeted by chaperones and delivered to lysosomes where they are translocated into the lysosomal lumen and degraded via the lysosome-associated membrane protein type 2A (LAMP-2A). Mutations in LAMP2 that inhibit autophagy result in Danon disease characterized by hypertrophic cardiomyopathy. The ryanodine receptor type 2 (RyR2) plays a key role in cardiomyocyte excitation–contraction and its dysfunction can lead to cardiac failure. Whether RyR2 is degraded by CMA is unknown. Methods and results To induce CMA, cultured neonatal rat cardiomyocytes were treated with geldanamycin (GA) to promote protein degradation through this pathway. GA increased LAMP-2A levels together with its redistribution and colocalization with Hsc70 in the perinuclear region, changes indicative of CMA activation. The inhibition of lysosomes but not proteasomes prevented the loss of RyR2. The recovery of RyR2 content after incubation with GA by siRNA targeting LAMP-2A suggests that RyR2 is degraded via CMA. In silico analysis also revealed that the RyR2 sequence harbours six KFERQ motifs which are required for the recognition Hsc70 and its degradation via CMA. Our data suggest that presenilins are involved in RyR2 degradation by CMA. Conclusion These findings are consistent with a model in which oxidative damage of the RyR2 targets it for turnover by presenilins and CMA, which could lead to removal of damaged or leaky RyR2 channels. PMID:23404999

  15. Papel fundamental de cFLIP en el control de la apoptosis en células epiteliales de mama

    OpenAIRE

    Yerbes, Rosario

    2010-01-01

    TRAIL es un ligando de muerte de la familia de TNF con un gran potencial terapéutico contra el cáncer, debido fundamentalmente a que es capaz de inducir apoptosis en células tumorales sin provocar toxicidad en células normales. Sin embargo, existen algunos tipos de células tumorales, como las de mama, que presentan resistencia a la apoptosis inducida por TRAIL por causas no bien conocidas. En esta tesis se ha estudiado el papel que cFLIP, proteína inhibidora de la apoptosis inducida por ligan...

  16. Manganese-Mediated Lignin Degradation by Pleurotus pulmonarius

    OpenAIRE

    Camarero, S.; Bockle, B.; Martinez, M. J.; Martinez, A.T.

    1996-01-01

    Pleurotus pulmonarius produced the strongest degradation of lignin during solid-state fermentation of [(sup14)C]lignin wheat straw with different fungi. A manganese-oxidizing peroxidase seemed to be involved in lignin attack, since the addition of Mn(sup2+) to the culture increased lignin mineralization by ca. 125%. This enzyme was purified and characterized from both solid-state fermentation and liquid cultures.

  17. c - FLIP 调节 TRAIL 诱导胃癌细胞凋亡敏感性的研究%Study ni the regulatini nf c-FLIP fnr the seisitivity nf TRAIL-iiduced annntnsis nf gastric caicer cells

    Institute of Scientific and Technical Information of China (English)

    蔡军; 尹杰; 郑智; 张军

    2015-01-01

    Objective To explore the role of c - FLIP in TRAIL induced cell apoptosis in gastric carcinoma cells. Methnds The surviv-al rate of cells was detected by MTT. Two SiRNAs targeting c - FLIP genes were transfected into SGC - 7901 cells by lipofectamine 2000 reagent. The effect of decrease of expression of c - FLIP was detected by qPCR and Western blot. The apoptotic rate of SGC - 7901 cells after treatment with TRAIL was analyzed by Hoechst 33258 staining and flow cytometry. Caspase - 8 and activated caspase - 8 were detected by Western blot. Results c - FLIP mRNA and protein were significantly decreased by c - FLIP siRNAs,especially the second siRNA. At 24 h after exposure of gastric carcinoma cells in TRAIL with different dosages of 1,10,100,and 1 000 ng/ ml,the cell survival rates were 98. 9% ,94. 8% ,91. 7%and 83. 7% respectively. There was no significant difference between control group and TRAIL group. After treatment with 100 ng/ ml TRAIL for 24 h,cell survival rate was significantly declined when the c - FLIP gene was knocked down,and the survival rate was 62. 8% in control group. After treatment with 100 ng/ ml TRAIL for 24 h,the rates of apoptotic cells detected by Hoechst 33258 staining were 12. 5% in TRAIL treatment group,17. 4% in TRAIL combined with c - FLIP - Si - NC treatment group,and 48. 7 % in TRAIL combined with c - FLIP - SiRNA treatment group. The results of FCM showed that the rate of apoptotic cells was 14. 76% ,it was higher than that of other two groups( P 0.05)。凋亡实验显示在二者共同作用 SGC7901细胞24 h 后,能够促进细胞的凋亡。Western blot 结果显示二者共同作用24 h 后,c - FLIP 显著降低、caspase -8及激活型 caspase -8(p -18)的表达均显著升高。结论抑制 c - FLIP 的表达增强了 TRAIL 诱导胃癌细胞 SGC7901的凋亡。

  18. Upregulation of c-FLIP-short in response to TRAIL promotes survival of NSCLC cells, which could be suppressed by inhibition of Ca2+/calmodulin signaling

    Czech Academy of Sciences Publication Activity Database

    Kaminskyy, V.O.; Surova, O.V.; Piskunova, T.; Zborovskaya, I.B.; Tchevkina, E.M.; Anděra, Ladislav; Zhivotovsky, B.

    2013-01-01

    Roč. 4, březen 2013 (2013), e522. ISSN 2041-4889 Institutional support: RVO:68378050 Keywords : TRAIL * DR4 * c-FLIPS * calcium * calmodulin * lung adenocarcinoma Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 5.177, year: 2013

  19. RNAi靶向沉默c-FLIP(L)基因对大肠癌细胞凋亡的影响

    Institute of Scientific and Technical Information of China (English)

    杜亚平; 张泽富; 忽景泰; 吴怀敏; 谢建军

    2013-01-01

    目的应用RNAi技术将c-FLIP(L)对应的SiRNA片段对大肠癌细胞株SW480凋亡的影响,明确RNAi靶向沉默c-FLIP基因在TRAIL介导的凋亡途径中的作用。方法与c-FLIP(L)对应的SiRNA片段转染入细胞,半定量RT-PCR法判断干扰前后FLIPmRNA水平的变化,Westernblot分析FLIP蛋白水平变化,比较分析干扰前后细胞对介导的凋亡敏感性的改变及转染前后TRAIL诱导的细胞凋亡的情况。结果 c-FLIP(L)可以减低SW480中FLIPmRNA和蛋白水平(P<0.01),转染FLIP-siRNA后,TRAIL对大肠癌胞株SW480的遏制作用显著加强(P<0.05),TRAIL介导凋亡明显增高(P<0.05)。结论 RNAi靶向沉默c-FLIP(L)并能提高SW480对TRAIL灵敏度并诱使SW480凋亡。

  20. A Peptide-mediated Fenton Reaction in Wood-degrading Fungi

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Gt factor is a low-molecular-weight peptide isolated from the extracellular culture of wood-degrading fungus Gloeophyllum trabeum. It is capable of enhancing degradation of cellulose. Its action mechanism was investigated and it was found that Gt factor could reduce Fe3+ to Fe2+. Electron paramagnetic resonance (EPR) spectroscopy revealed in the presence of O2, Gt factor could drive the formation of H2O2 via a superoxide anion O2.- intermediate and mediate the generation of hydroxyl radical HO˙ in a Fenton-type reaction. All these provided evidence for the formation of HO˙ in some wood-degrading fungi.

  1. Factors mediating the restoration of structurally degraded soils

    DEFF Research Database (Denmark)

    Arthur, Emmanuel; Moldrup, Per; Schjønning, Per;

    the incubation period, structural stability estimated as the amount of water-dispersible clay decreased with prevailing moisture content, and native organic matter. Also, microbial activity significantly increased with addition of exogenous organic matter. At the end of incubation, there was...... kaolinitic soil and lowest for the smectitic soil. Among the illitic soils, aggregate workability increased with native organic matter content. Addition of exogenous organic material showed little effect on soil physical properties. Results points to the possibility of regenerating the structure of......Soil structure is essential for sustained provision of ecosystem services such as water filtering and storage, waste disposal, carbon sequestration and many more. Structural degradation/disaggregation of soils emanating from human activities such as mining, grading and filling interferes with the...

  2. Benzoxazinone-Mediated Triazine Degradation: A Proposed Reaction Mechanism.

    Science.gov (United States)

    Willett, C D; Lerch, R N; Lin, C-H; Goyne, K W; Leigh, N D; Roberts, C A

    2016-06-22

    The role of benzoxazinones (Bx, 2-hydroxy-2H-1,4-benzoxazin-3(4H)-one) in triazine resistance in plants has been studied for over half a century. In this research, fundamental parameters of the reaction between DIBOA-Glc (2-β-d-glucopyranosyloxy-4-hydroxy-1,4-benzoxazin-3-one) and atrazine (ATR, 6-chloro-N-ethyl-N'-(1-methylethyl)-1,3,5-triazine-2,4-diamine) were examined. Through a series of experiments employing a variety of chromatographic and spectroscopic techniques, the DIBOA-Glc/ATR reaction was characterized in terms of reactant and product kinetics, stoichiometry, identification of a reaction intermediate, and reaction products formed. Results of these experiments demonstrated that the reaction mechanism proceeds via nucleophilic attack of the hydroxamic acid moiety of DIBOA-Glc at the C-2 position of the triazine ring to form hydroxyatrazine (HA, 2-hydroxy-4-ethylamino-6-isopropylamino-s-triazine), with associated degradation of DIBOA-Glc. Degradation of reactants followed first-order kinetics with a noncatalytic role of DIBOA-Glc. A reaction intermediate was identified as a DIBOA-Glc-HA conjugate, indicating a 1:1 DIBOA-Glc:ATR stoichiometry. Reaction products included HA and Cl(-), but definitive identification of DIBOA-Glc reaction product(s) was not attained. With these reaction parameters elucidated, DIBOA-Glc can be evaluated in terms of its potential for a myriad of applications, including its use to address the problem of widespread ATR contamination of soil and water resources. PMID:27215133

  3. Relationship of c-FLIP (L) protein expression with molecular subtyping and clinical prognosis in invasive breast cancer%凋亡调节因子c-FLIP (L)与浸润性乳腺癌分子分型及预后的相关性

    Institute of Scientific and Technical Information of China (English)

    臧凤琳; 魏熙胤; 孙保存

    2014-01-01

    Objective To investigate the expression of apoptotic regulator c-FLIP(L) in invasive breast carcinoma tissues,and to evaluate its correlation with molecular subtyping and clinical prognosis.Methods Immunohistochemistry using EnVision staining for c-FLIP (L) was performed in 264 cases of invasive breast carcinomas and matched adjacent normal breast tissue samples from January 1996 to December 1999.ER,PR,HER2,Ki-67,CK5/6 and EGFR were evaluated by immunohistochemistry in order to classify the tumors into five molecular subtypes and the difference of c-FLIP(L) expression in these molecular subtypes was also analyzed.The influence of c-FLIP(L) expression on prognosis was evaluated by Kaplan-Meier curves and multi-factor Cox proportional risk model.Results High expression of c-FLIP(L) was observed in 84.5% (223/264) of cases of invasive breast carcinomas which were significantly higher than the 45.1% (119/264) of cases in adjacent normal epithelium of breast (x2 =89.78,P =0.000).The expression of c-FLIP(L) in luminal B (HER2 positive) and basal-like breast cancers was 78.1% (25/32) and 46.2% (18/39),respectively,with significant difference (P < 0.05).Moreover,the expression of c-FLIP(L) in luminal B (HER2 positive) was higher than in luminal A cancers (P < 0.05),and the expression of c-FLIP(L) in HER2 positive cancers was higher than in basal-like cancers (P <0.01).C-FLIP(L) showed deep yellow staining in node positive breast cancer with a high-expression rate of 93.1% (134/144); whereas the expression was sporadic and light yellow in node negative breast cancer with a lower high-expressed rate of 72.5% (87/120,P < 0.01).C-FLIP(L) expression had significant influence on disease-free survival time,with c-FLIP(L)-positive patients showing poor prognosis (P < 0.01).Multifactor Cox proportional risk model analysis showed that expression of c-FLIP (L),lymph nodes status and molecular subtypes were independent prognostic factors for invasive breast

  4. Chronic exposure to paclitaxel diminishes phosphoinositide signaling by calpain-mediated neuronal calcium sensor-1 degradation.

    Science.gov (United States)

    Boehmerle, Wolfgang; Zhang, Kun; Sivula, Michael; Heidrich, Felix M; Lee, Yashang; Jordt, Sven-Eric; Ehrlich, Barbara E

    2007-06-26

    Paclitaxel (Taxol) is a well established chemotherapeutic agent for the treatment of solid tumors, but it is limited in its usefulness by the frequent induction of peripheral neuropathy. We found that prolonged exposure of a neuroblastoma cell line and primary rat dorsal root ganglia with therapeutic concentrations of Taxol leads to a reduction in inositol trisphosphate (InsP(3))-mediated Ca(2+) signaling. We also observed a Taxol-specific reduction in neuronal calcium sensor 1 (NCS-1) protein levels, a known modulator of InsP(3) receptor (InsP(3)R) activity. This reduction was also found in peripheral neuronal tissue from Taxol treated animals. We further observed that short hairpin RNA-mediated NCS-1 knockdown had a similar effect on phosphoinositide-mediated Ca(2+) signaling. When NCS-1 protein levels recovered, so did InsP(3)-mediated Ca(2+) signaling. Inhibition of the Ca(2+)-activated protease mu-calpain prevented alterations in phosphoinositide-mediated Ca(2+) signaling and NCS-1 protein levels. We also found that NCS-1 is readily degraded by mu-calpain in vitro and that mu-calpain activity is increased in Taxol but not vehicle-treated cells. From these results, we conclude that prolonged exposure to Taxol activates mu-calpain, which leads to the degradation of NCS-1, which, in turn, attenuates InsP(3)mediated Ca(2+) signaling. These findings provide a previously undescribed approach to understanding and treating Taxol-induced peripheral neuropathy. PMID:17581879

  5. c-FLIP反义寡核苷酸诱导胚胎型横纹肌肉瘤细胞凋亡的研究%Study of c-FLIP-ASODN induced apoptosis in human rhabdomyosarcoma cells

    Institute of Scientific and Technical Information of China (English)

    聂友华; 魏锐利

    2006-01-01

    目的探讨c-FLIP反义寡核苷酸(c-FLIP antisense oligodeoxynudeotide,c-FLIP-ASODN)对c-FLIP的表达调控及诱导人胚胎型横纹肌肉瘤(rhabdomyosarcoma,RD)细胞凋亡的作用.方法以脂质体为载体,将c-FLIP-ASODN及对照序列分别转染RD细胞,分别通过Western Blotting、RT-PCR方法检测ASODN对c-FLIP蛋白和mRNA表达量的调控,用流式细胞术测定ASODN干预前后RD细胞凋亡率的变化.结果与对照序列相比,Western印迹显示,转染了c-FLIP-ASODN的RD细胞其FLIPs和FLIPL的表达量分别下降为空白对照组的51%和57%;RT-PCR检测表明c-FLIP-ASODN能抑制c-FLIPmRNA的表达;诱导凋亡48 h后,转染c-FLIP-ASODN的RD细胞凋亡率升高(29.3±6.3)%.结论c-FLIP-ASODN可有效转染RD细胞,下调c-FLIP mRNA表达,从而诱导RD细胞的凋亡,成为眼眶RD基因治疗的新靶向.

  6. XPB mediated retroviral cDNA degradation coincides with entry to the nucleus

    International Nuclear Information System (INIS)

    Retroviruses must integrate their cDNA to a host chromosome, but a significant fraction of retroviral cDNA is degraded before integration. XPB and XPD are part of the TFIIH complex which mediates basal transcription and DNA nucleotide excision repair. Retroviral infection increases when XPB or XPD are mutant. Here we show that inhibition of mRNA or protein synthesis does not affect HIV cDNA accumulation suggesting that TFIIH transcription activity is not required for degradation. Other host factors implicated in the stability of cDNA are not components of the XPB and XPD degradation pathway. Although an increase of retroviral cDNA in XPB or XPD mutant cells correlates with an increase of integrated provirus, the integration efficiency of pre-integration complexes is unaffected. Finally, HIV and MMLV cDNA degradation appears to coincide with nuclear import. These results suggest that TFIIH mediated cDNA degradation is a nuclear host defense against retroviral infection.

  7. Debra-Mediated Ci Degradation Controls Tissue Homeostasis in Drosophila Adult Midgut

    OpenAIRE

    Zhouhua Li; Yueqin Guo; Lili Han; Yan Zhang; Lai Shi; Xudong Huang; Xinhua Lin

    2014-01-01

    Summary Adult tissue homeostasis is maintained by resident stem cells and their progeny. However, the underlying mechanisms that control tissue homeostasis are not fully understood. Here, we demonstrate that Debra-mediated Ci degradation is important for intestinal stem cell (ISC) proliferation in Drosophila adult midgut. Debra inhibition leads to increased ISC activity and tissue homeostasis loss, phenocopying defects observed in aging flies. These defects can be suppressed by depleting Ci, ...

  8. Recombinant equine interleukin-1β induces putative mediators of articular cartilage degradation in equine chondrocytes

    OpenAIRE

    Tung, J. T.; Fenton, J. I.; Arnold, C; Alexander, L.; Yuzbasiyan-Gurkan, V.; Venta, P J; Peters, T. L.; Orth, M W; Richardson, D. W.; Caron, J P

    2002-01-01

    Interleukin-1 is considered a central mediator of cartilage loss in osteoarthritis in several species, however an equine recombinant form of this cytokine is not readily available for in vitro use in equine osteoarthritis research. Equine recombinant interleukin-1β was cloned and expressed and its effects on the expression and activity of selected chondrocytic proteins implicated in cartilage matrix degradation were characterized. Reverse transcriptase polymerase chain reaction methods were u...

  9. Negative feedback regulation of cellular antiviral signaling by RBCK1-mediated degradation of IRF3

    Institute of Scientific and Technical Information of China (English)

    Min Zhang; Yang Tian; Rui-Peng Wang; Dong Gao; Yan Zhang; Fei-Ci Diao; Dan-Ying Chen; Zhong-He Zhai; Hong-Bing Shu

    2008-01-01

    Viral infection causes host cells to produce type Ⅰ interferons (IFNs), which are critically involved in viral clearance. Previous studies have demonstrated that activation of the transcription factor interferon regulatory factor (IRF)3 is essential for virus-triggered induction of type Ⅰ IFNs. Here we show that the E3 ubiquitin ligase RBCC protein interact-ing with PKC1 (RBCK1) catalyzes the ubiquitination and degradation of IRF3. Overexpression of RBCK1 negatively regulates Sendai virus-triggered induction of type Ⅰ IFNs, while knockdown of RBCK1 has the opposite effect. Plaque assays consistently demonstrate that RBCK1 negatively regulates the cellular antiviral response. Furthermore, viral infection leads to induction of RBCK1 and subsequent degradation of IRF3. These findings suggest that the cellular antiviral response is controlled by a negative feedback regulatory mechanism involving RBCK1-mediated ubiquitina-tion and degradation of IRF3.

  10. Cdt2-mediated XPG degradation promotes gap-filling DNA synthesis in nucleotide excision repair.

    Science.gov (United States)

    Han, Chunhua; Wani, Gulzar; Zhao, Ran; Qian, Jiang; Sharma, Nidhi; He, Jinshan; Zhu, Qianzheng; Wang, Qi-En; Wani, Altaf A

    2015-01-01

    Xeroderma pigmentosum group G (XPG) protein is a structure-specific repair endonuclease, which cleaves DNA strands on the 3' side of the DNA damage during nucleotide excision repair (NER). XPG also plays a crucial role in initiating DNA repair synthesis through recruitment of PCNA to the repair sites. However, the fate of XPG protein subsequent to the excision of DNA damage has remained unresolved. Here, we show that XPG, following its action on bulky lesions resulting from exposures to UV irradiation and cisplatin, is subjected to proteasome-mediated proteolytic degradation. Productive NER processing is required for XPG degradation as both UV and cisplatin treatment-induced XPG degradation is compromised in NER-deficient XP-A, XP-B, XP-C, and XP-F cells. In addition, the NER-related XPG degradation requires Cdt2, a component of an E3 ubiquitin ligase, CRL4(Cdt2). Micropore local UV irradiation and in situ Proximity Ligation assays demonstrated that Cdt2 is recruited to the UV-damage sites and interacts with XPG in the presence of PCNA. Importantly, Cdt2-mediated XPG degradation is crucial to the subsequent recruitment of DNA polymerase δ and DNA repair synthesis. Collectively, our data support the idea of PCNA recruitment to damage sites which occurs in conjunction with XPG, recognition of the PCNA-bound XPG by CRL4(Cdt2) for specific ubiquitylation and finally the protein degradation. In essence, XPG elimination from DNA damage sites clears the chromatin space needed for the subsequent recruitment of DNA polymerase δ to the damage site and completion of gap-filling DNA synthesis during the final stage of NER. PMID:25483071

  11. The contribution of mediated oxidation mechanisms in the electrolytic degradation of cyanuric acid using diamond anodes.

    Science.gov (United States)

    Bensalah, Nasr; Dbira, Sondos; Bedoui, Ahmed

    2016-07-01

    In this work, the contribution of mediated oxidation mechanisms in the electrolytic degradation of cyanuric acid using boron-doped diamond (BDD) anodes was investigated in different electrolytes. A complete mineralization of cyanuric acid was obtained in NaCl; however lower degrees of mineralization of 70% and 40% were obtained in Na2SO4 and NaClO4, respectively. This can be explained by the nature of the oxidants electrogenerated in each electrolyte. It is clear that the contribution of active chlorine (Cl2, HClO, ClO(-)) electrogenerated from oxidation of chlorides on BDD is much more important in the electrolytic degradation of cyanuric acid than the persulfate and hydroxyl radicals produced by electro-oxidation of sulfate and water on BDD anodes. This could be explained by the high affinity of active chlorine towards nitrogen compounds. No organic intermediates were detected during the electrolytic degradation of cyanuric acid in any the electrolytes, which can be explained by their immediate depletion by hydroxyl radicals produced on the BDD surface. Nitrates and ammonium were the final products of electrolytic degradation of cyanuric acid on BDD anodes in all electrolytes. In addition, small amounts of chloramines were formed in the chloride medium. Low current density (≤10mA/cm(2)) and neutral medium (pH in the range 6-9) should be used for high efficiency electrolytic degradation and negligible formation of hazardous chlorate and perchlorate. PMID:27372125

  12. Effect of apotransferrin, lactoferrin and ovotransferrin on the hydroxyl radical mediated degradation of beta-glucan.

    Science.gov (United States)

    Faure, Audrey M; Nyström, Laura

    2016-08-01

    Beta-glucan is a polysaccharide widely accepted and used as a functional ingredient due to its positive effects on human health. However, beta-glucan is readily degraded in aqueous systems in presence of a hydroxyl radical generating system such as ascorbic/iron(II). In the present study, we tested whether iron binding proteins; apotransferrin, lactoferrin and ovotransferrin; could prevent the hydroxyl radical mediated degradation of beta-glucan. The radical formation was investigated by ESR spectroscopy and the polysaccharide degradation was monitored by the viscosity loss of the solutions. Apo-transferrin increased the formation of hydroxyl radicals and this related with a faster degradation of beta-glucan. Lactoferrin did not have any effect on the ascorbate induced degradation of beta-glucan, whereas ovotransferrin completely inhibited the hydroxyl radical generation by a system containing ascorbic acid and iron(II). However, the presence of ovotransferrin in beta-glucan decreased the viscosity of the solution, which was accompanied by the apparition of a precipitate, indicating a potential interaction between the protein and beta-glucan. FT-IR analyses indicate the presence of beta-glucan and ovotransferrin in both precipitate and supernatant, as well as the occurrence of interactions between the two compounds. This study reveals that ovotransferrin is a promising candidate for inhibiting the formation of ascorbate/iron(II) induced hydroxyl radicals in beta-glucan solutions. PMID:26988468

  13. Cdc20 mediates D-box-dependent degradation of Sp100

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Ran; Li, Ke-min; Zhou, Cai-hong; Xue, Jing-lun [State Key Laboratory of Genetic Engineering, Institute of Genetics, School of Life Science, Fudan University, Shanghai (China); Ji, Chao-neng, E-mail: Chnji@fudan.edu.cn [State Key Laboratory of Genetic Engineering, Institute of Genetics, School of Life Science, Fudan University, Shanghai (China); Chen, Jin-zhong, E-mail: kingbellchen@fudan.edu.cn [State Key Laboratory of Genetic Engineering, Institute of Genetics, School of Life Science, Fudan University, Shanghai (China)

    2011-12-02

    Highlights: Black-Right-Pointing-Pointer Cdc20 is a co-activator of APC/C complex. Black-Right-Pointing-Pointer Cdc20 recruits Sp100 and mediates its degradation. Black-Right-Pointing-Pointer The D-box of Sp100 is required for Cdc20-mediated degradation. Black-Right-Pointing-Pointer Sp100 expresses consistently at both the mRNA and protein levels in cell cycle. -- Abstract: Cdc20 is a co-activator of the anaphase-promoting complex/cyclosome (APC/C complex), which recruits substrates at particular phases of the cell cycle and mediates their degradation. Sp100 is a PML-NB scaffold protein, which localizes to nuclear particles during interphase and disperses from them during mitosis, participates in viral resistance, transcriptional regulation, and apoptosis. However, its metabolism during the cell cycle has not yet been fully characterized. We found a putative D-box in Sp100 using the Eukaryotic Linear Motif (ELM) predictor database. The putative D-box of Sp100 was verified by mutational analysis. Overexpression of Cdc20 resulted in decreased levels of both endogenous Sp100 protein and overexpressed Sp100 mRNA in HEK 293 cells. Only an overexpressed D-box deletion mutant of Sp100 accumulated in HEK293 cells that also overexpressed Cdc20. Cdc20 knockdown by cdc20 specific siRNA resulted in increased Sp100 protein levels in cells. Furthermore, we discovered that the Cdc20 mediated degradation of Sp100 is diminished by the proteasome inhibitor MG132, which suggests that the ubiquitination pathway is involved in this process. However, unlike the other Cdc20 substrates, which display oscillating protein levels, the level of Sp100 protein remains constant throughout the cell cycle. Additionally, both overexpression and knockdown of endogenous Sp100 had no effect on the cell cycle. Our results suggested that sp100 is a novel substrate of Cdc20 and it is degraded by the ubiquitination pathway. The intact D-box of Sp100 was necessary for this process. These findings expand

  14. Effect of apoptosis inhibiting gene c - FLIPs on proliferation and apoptosis of human lung adenocarcinoma cells%凋亡抑制基因c-FLIPs对人肺腺癌细胞增殖和凋亡的作用

    Institute of Scientific and Technical Information of China (English)

    卫萍; 李雪萍; 姜凤良; 罗秀成; 王爽; 张典; 李爱连

    2016-01-01

    Objective:To evaluate the effects of recombinant adenovirus apoptosis inhibiting gene c - FLIPs on proliferation and apoptosis of human lung adenocarcinoma cells. Methods:Recombinant adenovirus c - FLIPs was constructed and transfected to human lung adenocarcinoma cells Calu - 3. Real - time PCR detected c - FLIPs, Caspase - 8,Caspase - 10 and Bcl - 2,mononuclear cell direct cytotoxicity assay for cell proliferation,and flow cytom-etry for apoptotic after transfected. Results:Successfully constructed the over expression of recombinant adenoviral Ad5 c - FLIPs. Real - time PCR detected c - FLIPs expression in Calu - 3 cell with high expression,Caspase - 8, Caspase - 10 and Bcl - 2 expression with low expression. MTT assay found that over expression of c - FLIPs gene can induce cell proliferation. Apoptosis rate in control group(55. 17 ± 9. 68)% was higher than Calu - 3 cells(10. 97 ± 1. 66)% ,P < 0. 05. Conclusion:c - FLIPs can significantly induce the proliferation of human lung adenocarcinoma cells,and inhibit the apoptosis.%目的:探讨过表达凋亡抑制基因 c - FLIPs 重组腺病毒对人肺腺癌细胞增殖和凋亡的作用。方法:构建过表达凋亡抑制 c - FLIPs 的重组腺病毒 Ad5 c - FLIPs,感染人肺腺癌细胞 Calu -3。Real - time PCR 检测感染前后 c - FLIPs、Caspase -8,Caspase -10和 Bcl -2的表达。MTT 法检测细胞增殖。流式细胞仪检测感染Ad5 c - FLIPs 后人肺腺癌细胞的凋亡情况。结果:成功构建过表达 c - FLIPs 重组腺病毒 Ad5 c - FLIPs,real- time PCR 检测凋亡抑制基因 c - FLIPs 在 Calu -3细胞株高表达,过表达 c - FLIPs 基因,凋亡相关基因Caspase -8、Caspase -10和 Bcl -2的表达明显降低。MTT 法检测感染前后细胞增殖情况发现,过表达 c -FLIPs 基因可诱导细胞增殖,流式细胞仪分析经 PI 染色后的 Calu -3细胞株,对照组和腺病毒感染组细胞的凋亡率分别为(55.17±9.68)%和(10.97±1.66)%,

  15. Dependence of plasmin-mediated degradation of platelet adhesive receptors on temperature and Ca2+

    International Nuclear Information System (INIS)

    The effects of activation of plasminogen by streptokinase and tissue-type-plasminogen activator on platelet activation and the membrane glycoproteins (GPs) that mediate platelet adhesion and aggregation are not yet fully defined. To clarify effects on platelets during activation of plasminogen in vitro, we used monoclonal antibodies (MoAbs), flow cytometry, and platelets surface-labeled with 125I to characterize changes in receptors for fibrinogen (GPIIb-IIIa), von Willebrand factor (GPIb), and collagen (GPIa-IIa). Activation of plasminogen in plasma with pharmacologic concentrations of plasminogen activators did not degrade GPIIb-IIIa or GPIb, and caused only a modest decrease in GPIa. In washed platelets GPIIb-IIIa was extensively degraded by plasmin at 37 degrees C in the absence of exogenous Ca2+, conditions that destabilize the IIb-IIIa complex. Degradation of GPIb in washed platelets displayed a similar although less-marked dependence on temperature and the absence of Ca2+. The binding of activation-specific MoAbs did not increase during activation of plasminogen in plasma. We conclude that during pharmacologic fibrinolysis, reported inhibition of platelet function in plasma is not due to degradation of platelet-adhesive receptors. In addition, platelet activation observed during thrombolytic therapy does not appear to be a direct consequence of plasminogen activation

  16. Human macrophage foam cells degrade atherosclerotic plaques through cathepsin K mediated processes

    DEFF Research Database (Denmark)

    Barascuk, Natasha; Skjøt-Arkil, Helene; Register, Thomas C; Larsen, Lise; Byrjalsen, Inger; Christiansen, Claus; Karsdal, Morten A

    2010-01-01

    BACKGROUND: Proteolytic degradation of Type I Collagen by proteases may play an important role in remodeling of atherosclerotic plaques, contributing to increased risk of plaque rupture.The aim of the current study was to investigate whether human macrophage foam cells degrade the extracellular...... matrix (ECM) of atherosclerotic plaques by cathepsin K mediated processes. METHODS: We 1) cultured human macrophages on ECM and measured cathepsin K generated fragments of type I collagen (C-terminal fragments of Type I collagen (CTX-I) 2) investigated the presence of CTX-I in human coronary arteries and......-I in areas of intimal hyperplasia and in shoulder regions of advanced plaques. Treatment of human monocytes with M-CSF or M-CSF+LDL generated macrophages and foam cells producing CTX-I when cultured on type I collagen enriched matrix. Circulating levels of CTX-I were not significantly different in...

  17. Gene silencing: Double-stranded RNA mediated mRNA degradation and gene inactivation

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The recent development of gene transfer approaches in plants and animals has revealed that transgene can undergo silencing after integration in the genome. Host genes can also be silenced as a consequence of the presence of a homologous transgene. More and more investigations have demonstrated that doublestranded RNA can silence genes by triggering degradation of homologous RNA in the cytoplasm and by directing methylation of homologous nuclear DNA sequences. Analyses of Arabidopsis mutants and plant viral suppressors of silencing are unraveling RNA-silencing mechanisms and are assessing the role of methylation in transcriptional and posttranscriptional gene silencing. This review will focus on double-stranded RNA mediated mRNA degradation and gene inactivation in plants.

  18. Particulate matter air pollution disrupts endothelial cell barrier via calpain-mediated tight junction protein degradation

    Directory of Open Access Journals (Sweden)

    Wang Ting

    2012-08-01

    Full Text Available Abstract Background Exposure to particulate matter (PM is a significant risk factor for increased cardiopulmonary morbidity and mortality. The mechanism of PM-mediated pathophysiology remains unknown. However, PM is proinflammatory to the endothelium and increases vascular permeability in vitro and in vivo via ROS generation. Objectives We explored the role of tight junction proteins as targets for PM-induced loss of lung endothelial cell (EC barrier integrity and enhanced cardiopulmonary dysfunction. Methods Changes in human lung EC monolayer permeability were assessed by Transendothelial Electrical Resistance (TER in response to PM challenge (collected from Ft. McHenry Tunnel, Baltimore, MD, particle size >0.1 μm. Biochemical assessment of ROS generation and Ca2+ mobilization were also measured. Results PM exposure induced tight junction protein Zona occludens-1 (ZO-1 relocation from the cell periphery, which was accompanied by significant reductions in ZO-1 protein levels but not in adherens junction proteins (VE-cadherin and β-catenin. N-acetyl-cysteine (NAC, 5 mM reduced PM-induced ROS generation in ECs, which further prevented TER decreases and atteneuated ZO-1 degradation. PM also mediated intracellular calcium mobilization via the transient receptor potential cation channel M2 (TRPM2, in a ROS-dependent manner with subsequent activation of the Ca2+-dependent protease calpain. PM-activated calpain is responsible for ZO-1 degradation and EC barrier disruption. Overexpression of ZO-1 attenuated PM-induced endothelial barrier disruption and vascular hyperpermeability in vivo and in vitro. Conclusions These results demonstrate that PM induces marked increases in vascular permeability via ROS-mediated calcium leakage via activated TRPM2, and via ZO-1 degradation by activated calpain. These findings support a novel mechanism for PM-induced lung damage and adverse cardiovascular outcomes.

  19. c-FLIP与细胞凋亡及肿瘤靶向治疗%c-FLIP and apoptosis and targeted antitumour therapy

    Institute of Scientific and Technical Information of China (English)

    聂友华; 魏锐利

    2005-01-01

    细胞型FLIP(c-FLIP)是近年来发现的细胞凋亡过程中的抑制蛋白.凋亡过程是通过结合死亡受体(DR)而触发的,例如Fas或TRAIL.通过征募结合DR复合体阻止caspase的活化,从而抑制细胞凋亡.已明确c-FLIP的过表达与多种肿瘤的发生、发展有密切关系.

  20. Cisplatin Restores TRAIL apoptotic pathway in Glioblastoma-Derived Stem Cells through Up-regulation of DR5 and Down-regulation of c-FLIP

    OpenAIRE

    Ding, Lijuan; Yuan, Changji; Wei, Feng; Wang, Guangyi; Zhang, Jing; Bellail, Anita C.; Zhang, Zhaobin; Olson, Jeffrey J.; Hao, Chunhai

    2011-01-01

    Glioblastoma-derived stem cells (GSCs) are responsible for the cancer resistance to therapies. We show here that GSC-enriched neurospheres are resistant to the treatment of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) due to the insufficient expression of the death receptor DR4 and DR5 and the overexpression of cellular Fas-associated death domain-like interleukin-1β-converting enzyme-inhibitory protein (c-FLIP). However, treatment with cisplatin leads to the upregulation o...

  1. Memory formation for trace fear conditioning requires ubiquitin-proteasome mediated protein degradation in the prefrontal cortex.

    OpenAIRE

    Helmstetter, Fred J.

    2013-01-01

    The cellular mechanisms supporting plasticity during memory consolidation have been a subject of considerable interest. De novo protein and mRNA synthesis in several brain areas are critical, and more recently protein degradation, mediated by the ubiquitin-proteasome system (UPS), has been shown to be important. Previous work clearly establishes a relationship between protein synthesis and protein degradation in the amygdala, but it is unclear whether cortical mechanisms of memory consolidati...

  2. Debra-Mediated Ci Degradation Controls Tissue Homeostasis in Drosophila Adult Midgut

    Directory of Open Access Journals (Sweden)

    Zhouhua Li

    2014-02-01

    Full Text Available Adult tissue homeostasis is maintained by resident stem cells and their progeny. However, the underlying mechanisms that control tissue homeostasis are not fully understood. Here, we demonstrate that Debra-mediated Ci degradation is important for intestinal stem cell (ISC proliferation in Drosophila adult midgut. Debra inhibition leads to increased ISC activity and tissue homeostasis loss, phenocopying defects observed in aging flies. These defects can be suppressed by depleting Ci, suggesting that increased Hedgehog (Hh signaling contributes to ISC proliferation and tissue homeostasis loss. Consistently, Hh signaling activation causes the same defects, whereas depletion of Hh signaling suppresses these defects. Furthermore, the Hh ligand from multiple sources is involved in ISC proliferation and tissue homeostasis. Finally, we show that the JNK pathway acts downstream of Hh signaling to regulate ISC proliferation. Together, our results provide insights into the mechanisms of stem cell proliferation and tissue homeostasis control.

  3. Down-regulation of c-FLIP Gene by siRNA Interference Enhances Breast Cancer Cells to TRAIL-Induced Apoptosis%抑制c-FLIP基因促进TRAIL诱导的乳腺癌细胞凋亡

    Institute of Scientific and Technical Information of China (English)

    王希超; 刘相萍; 温艳玲; 吕志栋; 薛丹丹; 王海波

    2014-01-01

    目的:探讨抑制c-FLIP的表达对TRAIL诱导乳腺癌细胞MCF-7凋亡的影响.方法:重组腺病毒Ad-c-FLIP-siRNA和Ad-sTRAIL单独及联合感染对TRAIL耐药的乳腺癌细胞MCF-7,应用实时荧光定量聚合酶链反应(Real-time PCR)检测病毒感染后各组细胞内c-FLIP和TRAIL的mRNA表达变化;MTT法和结晶紫染色法检测MCF-7细胞活性,Hoechst33258荧光染色检测各组细胞的凋亡情况.结果:与阴性对照组比较,c-FLIP-siRNA组和c-FLIP-siRNA+TRAIL组c-FLIP的mRNA相对表达量分别是(0.32±0.16)和(0.39±0.48)倍;TRAIL组和c-FLIP-siRNA+TRAIL组TRAIL的mRNA相对表达量分别是(96.21±1.54)和(87.33±1.66)倍;TRAIL组、c-FLIP-siRNA组及c-FLIP-siRNA+TRAIL组的抑制率(%)分别为(60.27± 1.25)、(11.34±1.74)及(74.91± 2.12).对比阴性对照组的凋亡率(3.12± 1.54),TRAIL组(12.79±2.46)和c-FLIP-siRNA+TRAIL组(25.50±3.17)组的凋亡率明显增高(P<0.05),c-FLIP-siRNA组(6.85± 2.82)的凋亡率变化不明显,差异无统计学意义(P>0.05).结论:siRNA抑制c-FLIP基因的表达能显著促进TRAIL对乳腺癌细胞MCF-7凋亡的诱导作用.

  4. Studies on cell death and survival regulatory protein c-FLIP as a target for cancer treatment%以细胞存亡调控蛋白c-FLIP为靶点的癌症治疗研究

    Institute of Scientific and Technical Information of China (English)

    陈立立; 陈忠明; 王冠林; 张宽仁

    2014-01-01

    Many tumor cells are resistant to cell apoptosis through the expression of antiapoptotic proteins. c-FLIP is a ma-jor resistance protein of antiapoptosis. In human cells, there are three types of c-FLIP, c-FLIPL , c-FLIPS and c-FLIPR . The c-FLIP binds to FADD to prevent the formation of procaspase-8-DISC and the subsequent activation of caspase cascade. Further-more, c-FLIPL and c-FLIPS have multifunctional roles in various cellular signaling pathways, as well as up-regulating several cyto-protective signaling. Studies show that upregulation of c-FLIP has been found in various tumors, and its downregulation has been shown to restore apoptosis triggered by various chemothera-peutic agents, like the transcriptional regulating agents, trichos-tatin-A, camptothecin, cisplatin, doxorubicin, etc. or other new biotechnologies, such as the specific siRNA. Therefore, c-FLIPS are important targets of cancer therapy. This review summarizes the results on the role of c-FLIP in cancer chemotherapy of tradi-tional antitumor agents and siRNA, and to provide new ideas and rationales of searching for the antiapoptosis effective compounds that can specifically antagonize c-FLIP.%肿瘤细胞通过表达抗凋亡蛋白从而对细胞的凋亡产生耐受,这是肿瘤抗凋亡的重要调节机制。 c-FLIP是抗凋亡的主要抑制因子,在人类细胞中,c-FLIP主要有3种亚型,分别为c-FLIPL、c-FLIPS、c-FLIPR。 c-FLIP通过与FADD结合,从而影响了procaspase-8-DISC的形成及随后的caspase级联反应。此外, c-FLIPL 和c-FLIPS 在不同的信号途径中具有多种功能,可以同时上调许多具有细胞保护作用的信号。研究表明,c-FLIP在许多肿瘤细胞中都有所上调,但可以通过不同的化学治疗药物,如调控细胞转录水平的药物曲古抑菌素A、喜树碱、顺铂、阿霉素等传统化疗药或者通过一些最新的生物技术,如 siRNA 技术,使得 c-FLIP 表达水平有所下调,以此来恢复肿瘤细胞

  5. Phosphorylation Regulates Id2 Degradation and Mediates the Proliferation of Neural Precursor Cells.

    Science.gov (United States)

    Sullivan, Jaclyn M; Havrda, Matthew C; Kettenbach, Arminja N; Paolella, Brenton R; Zhang, Zhonghua; Gerber, Scott A; Israel, Mark A

    2016-05-01

    Inhibitor of DNA binding proteins (Id1-Id4) function to inhibit differentiation and promote proliferation of many different cell types. Among the Id family members, Id2 has been most extensively studied in the central nervous system (CNS). Id2 contributes to cultured neural precursor cell (NPC) proliferation as well as to the proliferation of CNS tumors such as glioblastoma that are likely to arise from NPC-like cells. We identified three phosphorylation sites near the N-terminus of Id2 in NPCs. To interrogate the importance of Id2 phosphorylation, Id2(-/-) NPCs were modified to express wild type (WT) Id2 or an Id2 mutant protein that could not be phosphorylated at the identified sites. We observed that NPCs expressing this mutant lacking phosphorylation near the N-terminus had higher steady-state levels of Id2 when compared to NPCs expressing WT Id2. This elevated level was the result of a longer half-life and reduced proteasome-mediated degradation. Moreover, NPCs expressing constitutively de-phosphorylated Id2 proliferated more rapidly than NPCs expressing WT Id2, a finding consistent with the well-characterized function of Id2 in driving proliferation. Observing that phosphorylation of Id2 modulates the degradation of this important cell-cycle regulator, we sought to identify a phosphatase that would stabilize Id2 enhancing its activity in NPCs and extended our analysis to include human glioblastoma-derived stem cells (GSCs). We found that expression of the phosphatase PP2A altered Id2 levels. Our findings suggest that inhibition of PP2A may be a novel strategy to regulate the proliferation of normal NPCs and malignant GSCs by decreasing Id2 levels. Stem Cells 2016;34:1321-1331. PMID:26756672

  6. Catalyst activation, deactivation, and degradation in palladium-mediated Negishi cross-coupling reactions.

    Science.gov (United States)

    Böck, Katharina; Feil, Julia E; Karaghiosoff, Konstantin; Koszinowski, Konrad

    2015-03-27

    Pd-mediated Negishi cross-coupling reactions were studied by a combination of kinetic measurements, electrospray-ionization (ESI) mass spectrometry, (31)P NMR and UV/Vis spectroscopy. The kinetic measurements point to a rate-determining oxidative addition. Surprisingly, this step seems to involve not only the Pd catalyst and the aryl halide substrate, but also the organozinc reagent. In this context, the ESI-mass spectrometric observation of heterobimetallic Pd-Zn complexes [L2 PdZnR](+) (L=S-PHOS, R=Bu, Ph, Bn) is particularly revealing. The inferred presence of these and related neutral complexes with a direct Pd-Zn interaction in solution explains how the organozinc reagent can modulate the reactivity of the Pd catalyst. Previous theoretical calculations by González-Pérez et al. (Organometallics- 2012, 31, 2053) suggest that the complexation by the organozinc reagent lowers the activity of the Pd catalyst. Presumably, a similar effect also causes the rate decrease observed upon addition of ZnBr2 . In contrast, added LiBr apparently counteracts the formation of Pd-Zn complexes and restores the high activity of the Pd catalyst. At longer reaction times, deactivation processes due to degradation of the S-PHOS ligand and aggregation of the Pd catalyst come into play, thus further contributing to the appreciable complexity of the title reaction. PMID:25709062

  7. Potential Landscape and Flux of p53-Mdm2 Oscillator Mediated by Mdm2 Degradation Rate

    Science.gov (United States)

    Bi, Yuanhong; Yang, Zhuoqin

    The dynamics of the tumor suppressor p53 can play a crucial role in deciding cell fate after DNA damage. In this paper, we explore the dynamics and stability of p53 mediated by Mdm2 degradation rate in p53-Mdm2 oscillator through bifurcation, the potential landscape and flux. Based on the investigation of the bifurcation, we find that p53 can exhibit rich dynamics including monostability, bistability of two stable steady states and oscillation behaviors as well as bistability between a stable steady state and an oscillatory state. The stability of these states are further validated by the potential landscape. In addition, oscillatory behaviors of p53 are explored by means of the negative gradient of the potential landscape and the probability flux. It is shown that the negative gradient of the potential landscape can attract the system towards the oscillatory path and the flux can drive oscillation along the path. Moreover, the quicker the flux runs, the smaller the period is. Besides, stability and sensitivity of the system are explored by the barrier height and the entropy production rate in a single cell level, and we further compare the potential landscapes at single and population cell levels. Our results may be useful for understanding the regulation of p53 signaling pathways in response to DNA damage.

  8. Memory formation for trace fear conditioning requires ubiquitin-proteasome mediated protein degradation in the prefrontal cortex.

    Directory of Open Access Journals (Sweden)

    David S Reis

    2013-10-01

    Full Text Available The cellular mechanisms supporting plasticity during memory consolidation have been a subject of considerable interest. De novo protein and mRNA synthesis in several brain areas are critical, and more recently protein degradation, mediated by the ubiquitin-proteasome system (UPS, has been shown to be important. Previous work clearly establishes a relationship between protein synthesis and protein degradation in the amygdala, but it is unclear whether cortical mechanisms of memory consolidation are similar to those in the amygdala. Recent work demonstrating a critical role for prefrontal cortex (PFC in the acquisition and consolidation of fear memory allows us to address this question. Here we use a PFC-dependent fear conditioning protocol to determine whether UPS mediated protein degradation is necessary for memory consolidation in PFC. Groups of rats were trained with auditory delay or trace fear conditioning and sacrificed 60 min after training. PFC tissue was then analyzed to quantify the amount of polyubiquinated protein. Other animals were trained with similar procedures but were infused with either a proteasome inhibitor (clasto-lactacystin β-lactone or a translation inhibitor (anisomycin in the PFC immediately after training. Our results show increased UPS-mediated protein degradation in the PFC following trace but not delay fear conditioning. Additionally, post-training proteasome or translation inhibition significantly impaired trace but not delay fear memory when tested the next day. Our results further support the idea that the PFC is critical for trace but not delay fear conditioning highlight the role of UPS-mediated degradation as critical for synaptic plasticity.

  9. USP7 Enforces Heterochromatinization of p53 Target Promoters by Protecting SUV39H1 from MDM2-Mediated Degradation

    OpenAIRE

    Sathish Kumar Mungamuri; Rui F. Qiao; Shen Yao; James J. Manfredi; Wei Gu; Stuart A. Aaronson

    2016-01-01

    The H3K9me3 repressive histone conformation of p53 target promoters is abrogated in response to p53 activation by MDM2-mediated SUV39H1 degradation. Here, we present evidence that the USP7 deubiquitinase protects SUV39H1 from MDM2-mediated ubiquitination in the absence of p53 stimulus. USP7 occupies p53 target promoters in unstressed conditions, a process that is abrogated with p53 activation associated with loss of the H3K9me3 mark on these same promoters. Mechanistically, USP7 forms a trime...

  10. BRCA1 loss activates cathepsin L–mediated degradation of 53BP1 in breast cancer cells

    OpenAIRE

    Grotsky, David A.; González-Suárez, Ignacio; Novell Álvarez, Anna; Neumann, Martin; Yaddanapudi, Sree C.; Croke, Monica; Martínez Alonso, Montserrat; Redwood, Abena B.; Ortega-Martinez, Sylvia; Feng, Zhihui; Lerma, Enrique; Ramon y Cajal, Teresa; Zhang, Junran; Matias-Guiu, Xavier; Dusso, Adriana

    2013-01-01

    Loss of 53BP1 rescues BRCA1 deficiency and is associated with BRCA1-deficient and triple-negative breast cancers (TNBC) and with resistance to genotoxic drugs. The mechanisms responsible for decreased 53BP1 transcript and protein levels in tumors remain unknown. Here, we demonstrate that BRCA1 loss activates cathepsin L (CTSL)–mediated degradation of 53BP1. Activation of this pathway rescued homologous recombination repair and allowed BRCA1-deficient cells to bypass growth arrest. Importantly...

  11. Exonuclease-mediated degradation of nascent RNA silences genes linked to severe malaria.

    Science.gov (United States)

    Zhang, Qingfeng; Siegel, T Nicolai; Martins, Rafael M; Wang, Fei; Cao, Jun; Gao, Qi; Cheng, Xiu; Jiang, Lubin; Hon, Chung-Chau; Scheidig-Benatar, Christine; Sakamoto, Hiroshi; Turner, Louise; Jensen, Anja T R; Claes, Aurelie; Guizetti, Julien; Malmquist, Nicholas A; Scherf, Artur

    2014-09-18

    Antigenic variation of the Plasmodium falciparum multicopy var gene family enables parasite evasion of immune destruction by host antibodies. Expression of a particular var subgroup, termed upsA, is linked to the obstruction of blood vessels in the brain and to the pathogenesis of human cerebral malaria. The mechanism determining upsA activation remains unknown. Here we show that an entirely new type of gene silencing mechanism involving an exonuclease-mediated degradation of nascent RNA controls the silencing of genes linked to severe malaria. We identify a novel chromatin-associated exoribonuclease, termed PfRNase II, that controls the silencing of upsA var genes by marking their transcription start site and intron-promoter regions leading to short-lived cryptic RNA. Parasites carrying a deficient PfRNase II gene produce full-length upsA var transcripts and intron-derived antisense long non-coding RNA. The presence of stable upsA var transcripts overcomes monoallelic expression, resulting in the simultaneous expression of both upsA and upsC type PfEMP1 proteins on the surface of individual infected red blood cells. In addition, we observe an inverse relationship between transcript levels of PfRNase II and upsA-type var genes in parasites from severe malaria patients, implying a crucial role of PfRNase II in severe malaria. Our results uncover a previously unknown type of post-transcriptional gene silencing mechanism in malaria parasites with repercussions for other organisms. Additionally, the identification of RNase II as a parasite protein controlling the expression of virulence genes involved in pathogenesis in patients with severe malaria may provide new strategies for reducing malaria mortality. PMID:25043062

  12. Applicability of boron-doped diamond electrode to the degradation of chloride-mediated and chloride-free wastewaters

    International Nuclear Information System (INIS)

    The electrochemical degradation of chloride-mediated and chloride-free dye wastewaters was investigated on a boron-doped diamond (BDD) electrode in comparison with that on a dimensionally stable anode (DSA), and the applicability of BDD electrode to the degradation of these two kinds of wastewaters was explored. In chloride-free wastewater, the electrochemical degradation efficiency of dye on BDD electrode was much higher than that on DSA, with a chemical oxygen demand (COD) removal of 100% and 26% for BDD and DSA, respectively. In chloride-mediated dye wastewater, COD removal was faster than that in chloride-free wastewater on both BDD and DSA electrodes with COD removal efficiencies higher than 95%, whereas the rate of COD removal on DSA was faster than that on BDD electrode. The investigation indicates that DSA is more suitable than BDD electrode in degradation of originally chloride contained dye wastewaters for the sake of energy and time saving. However, for chloride-free dye wastewaters, with the aim of environmental protection, BDD electrode is more appropriate to realize complete mineralization. At the same time, the secondary pollution can be avoided

  13. c-FLIP及Caspase-8表达在乳腺癌组织中的表达及临床意义%Expression of c-FLIP and Caspase-8 in Breast Cancer and Their Clinical Significance

    Institute of Scientific and Technical Information of China (English)

    潘峥; 陈军; 覃冠德; 覃思繁

    2012-01-01

    Objective To investigate the expression of c-FLIP and Caspase-8 in breast cancer and their correlation with metastasis and recurrence. Methods Immunohistochemisty was employed to determine the expression of c-FLIP and Caspase-8 in 80 breast carcinomas and paired adjacent breast tissues. Results c-FLIP was overexpressed in breast cancers compared with paired adjacent breast tissues. The expression of c-FLIP was significantly correlated with TNM stages, histological grade, axillary lymph node metastasis, the recurrence of tumor and the express of C-erbB-2. The expression of Caspase-8 was significantly lower in breast cancers compared with paired adjacent breast tissues. The expression of Caspase-8 was significantly correlated with histological grade, tumor size. There was a significantly negative relationship of c-FLIP with Caspase-8. Conclusion The overexpres-sion of c-FLIP and the inactivation of Caspase-8 might enhance the tumour cell proliferation and malignance in breast cancer.%目的 探讨凋亡相关蛋白c-FLIP和Caspase-8在人乳腺癌组织中的表达及相关性,分析其与乳腺癌转移复发的关系.方法 应用免疫组织化学法检测80例乳腺癌组织和相应的癌旁组织中c-FLIP和Caspase-8的表达情况.结果 80例乳腺癌组织中c-FLIP表达的阳性率显著高于相应的癌旁组织(P<0.05),c-FLIP的表达与TNM分期、组织学分级、腋窝淋巴结转移、术后复发及C-erbB-2表达密切相关(P<0.05);Caspase-8表达的阳性率显著低于相应的癌旁组织(P<0.05),Caspase-8的表达与组织学分级、肿瘤大小密切相关(P<0.05).c-FLIP表达和Caspase-8表达有显著负相关性(γ=-0.380,P=0.001).结论 c-FLIP的高表达及Caspase-8表达缺失可能在乳腺癌发生发展中起重要作用.

  14. Iron-mediated stabilization of soil carbon amplifies the benefits of ecological restoration in degraded lands.

    Science.gov (United States)

    Silva, Lucas C R; Doane, Timothy A; Corrêa, Rodrigo S; Valverde, Vinicius; Pereira, Engil I P; Horwath, William R

    2015-07-01

    unsuccessful attempts to restore mined areas through nutrient application alone, iron-mediated stabilization of vegetation inputs favored the regeneration of a barren stable state that had persisted for over five decades since disturbance. The effectiveness of coupled organic matter and iron "fertilization," combined with management of invasive species, has the possibility to enhance terrestrial carbon sequestration and accelerate the restoration of degraded lands, while addressing important challenges associated with urban waste disposal. PMID:26485951

  15. Clinical significance and expression of C-FLIP in human non-melanocytic skin tumors%c-FLIP在人非黑素细胞性皮肤肿瘤组织中的表达及其临床意义

    Institute of Scientific and Technical Information of China (English)

    刘晓庆; 涂亚庭

    2011-01-01

    Background and purpose: Human non-melanocytic skin tumors are the most common forms of skin tumors. Recent studies showed that c-FLIP plays a key role in the development of tumors. This study aimed to investigate the expression of c-FLIP protein in human non-melanocytic skin tumors and its clinical significance. Methods: The immunohistochemical method was used to determine the expression of c-FLIP in 81 human nonmelanocytic skin tumors. Results: The positive expressive rate of c-FLIP in 4 research groups are all significantly higher than in the normal control group, and therefore showed a statistical differences (P<0.01). The abnormal expression of c-FLIP in four research groups increase with malignancy of these diseases, but there were no statistical differences (P>0.05). The abnormal expression of c-FLIP in the SCC stage Ⅱ - Ⅲ were higher than that in the stage Ⅰ, but there were also no statistical differences (P>0.05). The positive expressive rate of c-FLIP in SCC correlated with the extent of infiltration and tumor metastasis (P<0.05). Conclusion: c-FLIP proteins play an important role in the genesis and progress of human non-melanocytic skin tumors.%背景与目的:非黑素细胞性皮肤肿瘤是皮肤肿瘤中最常见的一组类型,近来研究发现,c-FLIP在肿瘤的发生发展中发挥重要作用.本研究探讨c-FLIP在人非黑素细胞性皮肤肿瘤组织中的表达及其临床意义.方法:采用免疫组织化学SABC法检测81例人非黑素细胞性皮肤肿瘤组织标本和20例肿瘤周围正常皮肤组织和正常包皮组织标本中c-FLIP的表达水平,81例人非黑素细胞性皮肤肿瘤组织标本中,光线性角化病(actinic keratosis,AK)18例(AK组),鲍温样丘疹病(Bowenoid papulosiS,BP)15例(BP组),鲍温病(Bowen's disease,BD)16例(BD组),鳞状细胞癌(squamous cell carcinoma,SCC)32例(SCC组).分别统计比较各组c-FLIP阳性表达率在各临床病理学分级不同的疾病组

  16. Titanium Dioxide-Mediated Photcatalysed Degradation of Two Herbicide Derivatives Chloridazon and Metribuzin in Aqueous Suspensions

    Directory of Open Access Journals (Sweden)

    A. Khan

    2012-01-01

    Full Text Available The aim of this paper is to find out the optimal degradation condition for two potential environmental pollutants, chloridazon and metribuzin (herbicide derivatives, employing advanced oxidation process using TiO2 photocatalyst in aqueous suspensions. The degradation/mineralization of the herbicide was monitored by measuring the change in pollutant concentration and depletion in TOC content as a function of time. A detailed degradation kinetics was studied under different conditions such as types of TiO2 (anatase/anatase-rutile mixture, catalyst concentration, herbicide concentration, initial reaction pH, and in the presence of electron acceptors (hydrogen peroxide, ammonium persulphate, potassium persulphate in addition to atmospheric oxygen. The photocatalyst, Degussa P25, was found to be more efficient catalyst for the degradation of both herbicides as compared with two other commercially available TiO2 powders like Hombikat UV100 and PC500. Chloridazon (CHL was found to degrade more efficiently under acidic condition, whereas metribuzin (MET degraded faster under alkaline medium. All three electron acceptors tested in this study were found to enhance the degradation rate of both herbicides.

  17. A novel role for ATM in regulating proteasome-mediated protein degradation through suppression of the ISG15 conjugation pathway.

    Directory of Open Access Journals (Sweden)

    Laurence M Wood

    Full Text Available Ataxia Telangiectasia (A-T is an inherited immunodeficiency disorder wherein mutation of the ATM kinase is responsible for the A-T pathogenesis. Although the precise role of ATM in A-T pathogenesis is still unclear, its function in responding to DNA damage has been well established. Here we demonstrate that in addition to its role in DNA repair, ATM also regulates proteasome-mediated protein turnover through suppression of the ISG15 pathway. This conclusion is based on three major pieces of evidence: First, we demonstrate that proteasome-mediated protein degradation is impaired in A-T cells. Second, we show that the reduced protein turnover is causally linked to the elevated expression of the ubiquitin-like protein ISG15 in A-T cells. Third, we show that expression of the ISG15 is elevated in A-T cells derived from various A-T patients, as well as in brain tissues derived from the ATM knockout mice and A-T patients, suggesting that ATM negatively regulates the ISG15 pathway. Our current findings suggest for the first time that proteasome-mediated protein degradation is impaired in A-T cells due to elevated expression of the ISG15 conjugation pathway, which could contribute to progressive neurodegeneration in A-T patients.

  18. Sodium arsenite accelerates TRAIL-mediated apoptosis in melanoma cells through upregulation of TRAIL-R1/R2 surface levels and downregulation of cFLIP expression

    OpenAIRE

    Ivanov, Vladimir N.; Hei, Tom K.

    2006-01-01

    AP-1/cJun, NF-κB and STAT3 transcription factors control expression of numerous genes, which regulate critical cell functions including proliferation, survival and apoptosis. Sodium arsenite is known to suppress both the IKK-NF-κB and JAK2-STAT3 signaling pathways and to activate the MAPK/JNK-cJun pathways, thereby committing some cancers to undergo apoptosis. Indeed, sodium arsenite is an effective drug for the treatment of acute promyelocytic leukemia with little nonspecific toxicity. Malig...

  19. Effect of dentin etching and chlorhexidine application on metalloproteinase-mediated collagen degradation

    OpenAIRE

    Raquel, Osorio; Mónica, Yamauti; Estrella, Osorio; Estrella, Ruiz-Requena María; David, Pashley; Franklin, Tay; Manuel, Toledano

    2011-01-01

    Dentin matrix metalloproteinases (MMPs) are involved in collagen degradation of resin-dentin interfaces. This study evaluated if collagen degradation can be prevented by chlorhexidine after different dentin demineralization procedures. Human dentin demineralization was performed with phosphoric acid (PA), EDTA, or acidic monomers (ClearfilSEBond and XENOV). Specimens were stored (24 h, 1 wk or 3 wk) in the presence or absence of chlorhexidine. In half of the groups, active MMP-2 was incorpora...

  20. Thrombin and TNF-α/IL-1β Synergistically Induce Fibroblast-Mediated Collagen Gel Degradation

    OpenAIRE

    Fang, Qiuhong; Liu, Xiangde; Al-Mugotir, Mona; Kobayashi, Tetsu; Abe, Shinji; Kohyama, Tadashi; Rennard, Stephen I

    2006-01-01

    Degradation of preexisting and newly synthesized extracellular matrix is thought to play an important role in tissue remodeling. The current study evaluated whether thrombin and TNF-α/IL-1β could collaboratively induce collagen degradation by human fetal lung fibroblasts (HFL-1) and adult bronchial fibroblasts cultured in three-dimensional collagen gels. TNF-α/IL-1β alone induced production of matrix metalloproteinases (MMPs)-1, -3, and -9, which were released in latent form. With the additio...

  1. The mammalian homologue of yeast Afg1 ATPase (lactation elevated 1) mediates degradation of nuclear-encoded complex IV subunits.

    Science.gov (United States)

    Cesnekova, Jana; Rodinova, Marie; Hansikova, Hana; Houstek, Josef; Zeman, Jiri; Stiburek, Lukas

    2016-03-15

    Mitochondrial protein homeostasis is crucial for cellular function and integrity and is therefore maintained by several classes of proteins possessing chaperone and/or proteolytic activities. In the present study, we focused on characterization of LACE1 (lactation elevated 1) function in mitochondrial protein homeostasis. LACE1 is the human homologue of yeast mitochondrial Afg1 (ATPase family gene 1) ATPase, a member of the SEC18-NSF, PAS1, CDC48-VCP, TBP family. Yeast Afg1 was shown to mediate degradation of mitochondrially encoded complex IV subunits, and, on the basis of its similarity to CDC48 (p97/VCP), it was suggested to facilitate extraction of polytopic membrane proteins. We show that LACE1, which is a mitochondrial integral membrane protein, exists as part of three complexes of approximately 140, 400 and 500 kDa and is essential for maintenance of fused mitochondrial reticulum and lamellar cristae morphology. We demonstrate that LACE1 mediates degradation of nuclear-encoded complex IV subunits COX4 (cytochrome c oxidase 4), COX5A and COX6A, and is required for normal activity of complexes III and IV of the respiratory chain. Using affinity purification of LACE1-FLAG expressed in a LACE1-knockdown background, we show that the protein interacts physically with COX4 and COX5A subunits of complex IV and with mitochondrial inner-membrane protease YME1L. Finally, we demonstrate by ectopic expression of both K142A Walker A and E214Q Walker B mutants, that an intact ATPase domain is essential for LACE1-mediated degradation of nuclear-encoded complex IV subunits. Thus the present study establishes LACE1 as a novel factor with a crucial role in mitochondrial protein homeostasis. PMID:26759378

  2. C-FLIP在喉癌中的表达及临床意义%Expression and Its Significance of c- FLIP in Laryngeal Carcinoma

    Institute of Scientific and Technical Information of China (English)

    李晶; 王雪峰

    2006-01-01

    目的 探讨c-FLIP(细胞型Fas相关死亡域样白介素-1β转换酶抑制蛋白)在喉癌组织中的表达及临床意义.方法 应用免疫组织化学方法和流式细胞检测方法观察喉癌组织和声带息肉组织中c-FLIP表达情况.结果 喉癌组c-FLIP阳性表达率为81%(35/43),声带息肉组c-FLIP阳性表达率为0%(0/10),两者比较具有非常显著差异(P<0.01).c-FLIP表达与喉癌分期(早期与进展期)及淋巴结转移相关,染色度随喉鳞状细胞癌分期增高而增高并且有淋巴结转移的癌组织c-FLIP染色度,明显高于无淋巴结转移的喉癌组织.但与性别、年龄、肿瘤组织分级无明显关系.喉癌组与声带息肉组c-FLIP的平均荧光指数分别为4.73±0.74和1.06±0.18两者比较具有统计学意义(P<0.01).结论 c-FLIP在喉癌组织中表达增高,表明c-FLIP可能在喉癌的发生发展中起重要作用.

  3. βTrCP- and Rsk1/2-mediated degradation of BimEL inhibits apoptosis

    OpenAIRE

    Dehan, Elinor; Bassermann, Florian; Guardavaccaro, Daniele; Vasiliver-Shamis, Gaia; Cohen, Michael; Lowes, Kym; Dustin, Michael; Huang, David C. S.; Taunton, Jack; Pagano, Michele

    2009-01-01

    The BimEL tumor suppressor is a potent pro-apoptotic BH3-only protein. We found that in response to survival signals BimEL was rapidly phosphorylated on three serine residues in a conserved degron, facilitating binding and degradation via the F-box protein βTrCP. Phosphorylation of the BimEL degron was executed by Rsk1/2 and promoted by the Erk1/2-mediated phosphorylation of BimEL on Ser69. Compared to wild type BimEL, a BimEL phosphorylation mutant unable to bind βTrCP was stabilized and con...

  4. Human breast cancer cell-mediated bone collagen degradation requires plasminogen activation and matrix metalloproteinase activity

    Directory of Open Access Journals (Sweden)

    Hill Peter A

    2005-02-01

    Full Text Available Abstract Background Breast cancer cells frequently metastasize to the skeleton and induce extensive bone destruction. Cancer cells produce proteinases, including matrix metalloproteinases (MMPs and the plasminogen activator system (PAS which promote invasion of extracellular matrices, but whether these proteinases degrade bone matrix is unclear. To characterize the role that breast cancer cell proteinases play in bone degradation we compared the effects of three human breast cancer cell lines, MDA-MB-231, ZR-75-1 and MCF-7 with those of a normal breast epithelial cell line, HME. The cell lines were cultured atop radiolabelled matrices of either mineralized or non-mineralized bone or type I collagen, the principal organic constituent of bone. Results The 3 breast cancer cell lines all produced significant degradation of the 3 collagenous extracellular matrices (ECMs whilst the normal breast cell line was without effect. Breast cancer cells displayed an absolute requirement for serum to dissolve collagen. Degradation of collagen was abolished in plasminogen-depleted serum and could be restored by the addition of exogenous plasminogen. Localization of plasmin activity to the cell surface was critical for the degradation process as aprotinin, but not α2 antiplasmin, prevented collagen dissolution. During ECM degradation breast cancer cell lines expressed urokinase-type plasminogen activator (u-PA and uPA receptor, and MMPs-1, -3, -9,-13, and -14. The normal breast epithelial cell line expressed low levels of MMPs-1, and -3, uPA and uPA receptor. Inhibitors of both the PAS (aprotinin and PA inhibitor-1 and MMPs (CT1166 and tisue inhibitor of metalloproteinase blocked collagen degradation, demonstrating the requirement of both plasminogen activation and MMP activity for degradation. The activation of MMP-13 in human breast cancer cells was prevented by plasminogen activator inhibitor-1 but not by tissue inhibitor of metalloproteinase-1, suggesting

  5. Cullin 3 mediates SRC-3 ubiquitination and degradation to control the retinoic acid response

    Science.gov (United States)

    Ferry, Christine; Gaouar, Samia; Fischer, Benoit; Boeglin, Marcel; Paul, Nicodeme; Samarut, Eric; Piskunov, Aleksandr; Pankotai-Bodo, Gabriella; Brino, Laurent; Rochette-Egly, Cecile

    2011-01-01

    SRC-3 is an important coactivator of nuclear receptors including the retinoic acid (RA) receptor α. Most of SRC-3 functions are facilitated by changes in the posttranslational code of the protein that involves mainly phosphorylation and ubiquitination. We recently reported that SRC-3 is degraded by the proteasome in response to RA. Here, by using an RNAi E3-ubiquitin ligase entry screen, we identified CUL-3 and RBX1 as components of the E3 ubiquitin ligase involved in the RA-induced ubiquitination and subsequent degradation of SRC-3. We also show that the RA-induced ubiquitination of SRC-3 depends on its prior phosphorylation at serine 860 that promotes binding of the CUL-3–based E3 ligase in the nucleus. Finally, phosphorylation, ubiquitination, and degradation of SRC-3 cooperate to control the dynamics of transcription. In all, this process participates to the antiproliferative effect of RA. PMID:22147914

  6. An Intracellular Laccase Is Responsible for Epicatechin-Mediated Anthocyanin Degradation in Litchi Fruit Pericarp.

    Science.gov (United States)

    Fang, Fang; Zhang, Xue-lian; Luo, Hong-hui; Zhou, Jia-jian; Gong, Yi-hui; Li, Wen-jun; Shi, Zhao-wan; He, Quan; Wu, Qing; Li, Lu; Jiang, Lin-lin; Cai, Zhi-gao; Oren-Shamir, Michal; Zhang, Zhao-qi; Pang, Xue-qun

    2015-12-01

    In contrast to the detailed molecular knowledge available on anthocyanin synthesis, little is known about its catabolism in plants. Litchi (Litchi chinensis) fruit lose their attractive red color soon after harvest. The mechanism leading to quick degradation of anthocyanins in the pericarp is not well understood. An anthocyanin degradation enzyme (ADE) was purified to homogeneity by sequential column chromatography, using partially purified anthocyanins from litchi pericarp as a substrate. The purified ADE, of 116 kD by urea SDS-PAGE, was identified as a laccase (ADE/LAC). The full-length complementary DNA encoding ADE/LAC was obtained, and a polyclonal antibody raised against a deduced peptide of the gene recognized the ADE protein. The anthocyanin degradation function of the gene was confirmed by its transient expression in tobacco (Nicotiana benthamiana) leaves. The highest ADE/LAC transcript abundance was in the pericarp in comparison with other tissues, and was about 1,000-fold higher than the polyphenol oxidase gene in the pericarp. Epicatechin was found to be the favorable substrate for the ADE/LAC. The dependence of anthocyanin degradation by the enzyme on the presence of epicatechin suggests an ADE/LAC epicatechin-coupled oxidation model. This model was supported by a dramatic decrease in epicatechin content in the pericarp parallel to anthocyanin degradation. Immunogold labeling transmission electron microscopy suggested that ADE/LAC is located mainly in the vacuole, with essential phenolic substances. ADE/LAC vacuolar localization, high expression levels in the pericarp, and high epicatechin-dependent anthocyanin degradation support its central role in pigment breakdown during pericarp browning. PMID:26514808

  7. FBXL5-mediated degradation of single-stranded DNA-binding protein hSSB1 controls DNA damage response.

    Science.gov (United States)

    Chen, Zhi-Wei; Liu, Bin; Tang, Nai-Wang; Xu, Yun-Hua; Ye, Xiang-Yun; Li, Zi-Ming; Niu, Xiao-Min; Shen, Sheng-Ping; Lu, Shun; Xu, Ling

    2014-10-01

    Human single-strand (ss) DNA binding proteins 1 (hSSB1) has been shown to participate in DNA damage response and maintenance of genome stability by regulating the initiation of ATM-dependent signaling. ATM phosphorylates hSSB1 and prevents hSSB1 from ubiquitin-proteasome-mediated degradation. However, the E3 ligase that targets hSSB1 for destruction is still unknown. Here, we report that hSSB1 is the bona fide substrate for an Fbxl5-containing SCF (Skp1-Cul1-F box) E3 ligase. Fbxl5 interacts with and targets hSSB1 for ubiquitination and degradation, which could be prevented by ATM-mediated hSSB1 T117 phosphorylation. Furthermore, cells overexpression of Fbxl5 abrogated the cellular response to DSBs, including activation of ATM and phosphorylation of ATM targets and exhibited increased radiosensitivity, chemosensitivity and defective checkpoint activation after genotoxic stress stimuli. Moreover, the protein levels of hSSB1 and Fbxl5 showed an inverse correlation in lung cancer cells lines and clinical lung cancer samples. Therefore, Fbxl5 may negatively modulate hSSB1 to regulate DNA damage response, implicating Fbxl5 as a novel, promising therapeutic target for lung cancers. PMID:25249620

  8. Titanium dioxide-mediated heterogeneous photocatalytic degradation of terbufos: Parameter study and reaction pathways

    Energy Technology Data Exchange (ETDEWEB)

    Wu, R.-J. [Department of Applied Chemistry, Providence University, Taichung 433, Taiwan (China); Chen, C.-C. [Department of General Education, National Taichung Nursing College, Taichung 403, Taiwan (China); Chen, M.-H. [Department of Applied Chemistry, Providence University, Taichung 433, Taiwan (China); Lu, C.-S. [Department of General Education, National Taichung Nursing College, Taichung 403, Taiwan (China)], E-mail: cslu6@ntcnc.edu.tw

    2009-03-15

    The photocatalytic degradation of terbufos in aqueous suspensions was investigated by using titanium dioxide (TiO{sub 2}) as a photocatalyst. About 99% of terbufos was degraded after UV irradiation for 90 min. Factors such as pH of the system, TiO{sub 2} dosage, and presence of anions were found to influence the degradation rate. Photodegradation of terbufos by TiO{sub 2}/UV exhibited pseudo-first-order reaction kinetics, and a reaction quantum yield of 0.289. The electrical energy consumption per order of magnitude for photocatalytic degradation of terbufos was calculated and showed that a moderated efficiency (E{sub EO} = 71 kWh/(m{sup 3} order)) was obtained in TiO{sub 2}/UV process. To obtain a better understanding of the mechanistic details of this TiO{sub 2}-assisted photodegradation of terbufos with UV irradiation, the intermediates of the processes were separated, identified, and characterized by the solid-phase microextraction (SPME) and gas chromatography/mass spectrometry (GC/MS) technique. The probable photodegradation pathways were proposed and discussed.

  9. Titanium dioxide-mediated heterogeneous photocatalytic degradation of terbufos: Parameter study and reaction pathways

    International Nuclear Information System (INIS)

    The photocatalytic degradation of terbufos in aqueous suspensions was investigated by using titanium dioxide (TiO2) as a photocatalyst. About 99% of terbufos was degraded after UV irradiation for 90 min. Factors such as pH of the system, TiO2 dosage, and presence of anions were found to influence the degradation rate. Photodegradation of terbufos by TiO2/UV exhibited pseudo-first-order reaction kinetics, and a reaction quantum yield of 0.289. The electrical energy consumption per order of magnitude for photocatalytic degradation of terbufos was calculated and showed that a moderated efficiency (EEO = 71 kWh/(m3 order)) was obtained in TiO2/UV process. To obtain a better understanding of the mechanistic details of this TiO2-assisted photodegradation of terbufos with UV irradiation, the intermediates of the processes were separated, identified, and characterized by the solid-phase microextraction (SPME) and gas chromatography/mass spectrometry (GC/MS) technique. The probable photodegradation pathways were proposed and discussed

  10. Matrix metalloproteinase-13 mediated degradation of hyaluronic acid-based matrices orchestrates stem cell engraftment through vascular integration.

    Science.gov (United States)

    Jha, Amit K; Tharp, Kevin M; Browne, Shane; Ye, Jianqin; Stahl, Andreas; Yeghiazarians, Yerem; Healy, Kevin E

    2016-05-01

    A critical design parameter for the function of synthetic extracellular matrices is to synchronize the gradual cell-mediated degradation of the matrix with the endogenous secretion of natural extracellular matrix (ECM) (e.g., creeping substitution). In hyaluronic acid (HyA)-based hydrogel matrices, we have investigated the effects of peptide crosslinkers with different matrix metalloproteinases (MMP) sensitivities on network degradation and neovascularization in vivo. The HyA hydrogel matrices consisted of cell adhesive peptides, heparin for both the presentation of exogenous and sequestration of endogenously synthesized growth factors, and MMP cleavable peptide linkages (i.e., QPQGLAK, GPLGMHGK, and GPLGLSLGK). Sca1(+)/CD45(-)/CD34(+)/CD44(+) cardiac progenitor cells (CPCs) cultured in the matrices with the slowly degradable QPQGLAK hydrogels supported the highest production of MMP-2, MMP-9, MMP-13, VEGF165, and a range of angiogenesis related proteins. Hydrogels with QPQGLAK crosslinks supported prolonged retention of these proteins via heparin within the matrix, stimulating rapid vascular development, and anastomosis with the host vasculature when implanted in the murine hindlimb. PMID:26967648

  11. Slit-Robo signaling induces malignant transformation through Hakai-mediated E-cadherin degradation during colorectal epithelial cell carcinogenesis

    Institute of Scientific and Technical Information of China (English)

    Wei-Jie Zhou; Yan-Qing Ding; Jian-Guo Geng; Zhen H Geng; Shan Chi; Wenli Zhang; Xiao-Feng Niu; Shu-Jue Lan; Li Ma; Xuesong Yang; Li-Jing Wang

    2011-01-01

    The Slit family of guidance cues binds to Roundabout (Robo) receptors and modulates cell migration. We report here that ectopic expression of Slit2 and Robol or recombinant Slit2 treatment of Robol-expressing colorectal epithelial carcinoma cells recruited an ubiquitin ligase Hakai for E-cadherin (E-cad) ubiquitination and lysosomal degradation, epithelial-mesenchymal transition (EMT), and tumor growth and liver metastasis, which were rescued by knockdown of Hakai. In contrast, knockdown of endogenous Robol or specific blockade of Slit2 binding to Robol prevented E-cad degradation and reversed EMT, resulting in diminished tumor growth and liver metastasis.Ectopic expression of Robol also triggered a malignant transformation in Siit2-positive human embryonic kidney 293 cells. Importantly, the expression of Slit2 and Robol was significantly associated with an increased metastatic risk and poorer overall survival in colorectal carcinoma patients. We conclude that engagement of Robol by Slit2 induces malignant transformation through Hakai-mediated E-cad ubiquitination and lysosomal degradation during colorectal epithelial cell carcinogenesis.

  12. Degradation of Epidermal Growth Factor Receptor Mediates Dasatinib-Induced Apoptosis in Head and Neck Squamous Cell Carcinoma Cells

    Directory of Open Access Journals (Sweden)

    Yu-Chin Lin

    2012-06-01

    Full Text Available Epidermal growth factor receptor (EGFR is an important oncoprotein that promotes cell growth and proliferation. Dasatinib, a bcr-abl inhibitor, has been approved clinically for the treatment of chronic myeloid leukemia and demonstrated to be effective against solid tumors in vitro through Src inhibition. Here, we disclose that EGFR degradation mediated dasatinib-induced apoptosis in head and neck squamous cell carcinoma (HNSCC cells. HNSCC cells, including Ca9-22, FaDu, HSC3, SAS, SCC-25, and UMSCC1, were treated with dasatinib, and cell viability, apoptosis, and underlying signal transduction were evaluated. Dasatinib exhibited differential sensitivities against HNSCC cells. Growth inhibition and apoptosis were correlated with its inhibition on Akt, Erk, and Bcl-2, irrespective of Src inhibition. Accordingly, we found that down-regulation of EGFR was a determinant of dasatinib sensitivity. Lysosome inhibitor reversed dasatinib-induced EGFR down-regulation, and c-cbl activity was increased by dasatinib, indicating that dasatinib-induced EGFR down-regulation might be through c-cbl-mediated lysosome degradation. Increased EGFR activation by ligand administration rescued cells from dasatinib-induced apoptosis, whereas inhibition of EGFR enhanced its apoptotic effect. Estrogen receptor α (ERα was demonstrated to play a role in Bcl-2 expression, and dasatinib inhibited ERα at the pretranslational level. ERα was associated with EGFR in dasatinib-treated HNSCC cells. Furthermore, the xenograft model showed that dasatinib inhibited HSC3 tumor growth through in vivo down-regulation of EGFR and ERα. In conclusion, degradation of EGFR is a novel mechanism responsible for dasatinib-induced apoptosis in HNSCC cells.

  13. Trypsin-mediated enzymatic degradation of type II collagen in the human vitreous

    OpenAIRE

    van Deemter, Mariëlle; Kuijer, Roel; Harm Pas, Hendri; Jacoba van der Worp, Roelofje; Hooymans, Johanna Martina Maria; Los, Leonoor Inge

    2013-01-01

    Purpose Aging of the vitreous body can result in sight-threatening pathology. One aspect of vitreous aging is liquefaction, which results from the vanishing of collagen fibrils. We investigated the possibility that trypsins are involved in vitreous type II collagen degradation. Methods Immunohistochemistry and western blotting were used for detecting and locating trypsin isoforms in the vitreous and retina of human donor eyes. The capability of the retina to produce these trypsins was analyze...

  14. Copper-mediated oxidative degradation of catecholamines and oxidative damage of protein

    International Nuclear Information System (INIS)

    Full text. Degradative oxidation of catecholamines has been a matter of large interest in recent years due to the evidences associating their autoxidation with the etiology of neurotoxic and cardiotoxic processes. In this work we present data on the degradative oxidation of catecholamines of physiological importance: isoproterenol (IP), epinephrine (EP), norepinephrine (NEP), deoxyepinephrine (DEP) and dopamine (DA). The degradative oxidation of the catecholamines was followed by measurement of spectral changes and oxygen consumption by neutral aqueous solutions. The data show that Cu2+ strongly accelerated the rate of catecholamine oxidation, following the decreasing order; EP>DEP>IP>NEP>DA. The production of superoxide anion radical during catecholamine oxidation was very slow, even in the presence of Cu2+. The ability of IP to induce damages on bovine serum albumin (BSA) was determined by measuring the formation of carbonyl-groups in the protein, detected by reduction with tritiated Na BH4. The incubation of BSA with IP (50-500μM), in the presence of 100μM Cu2+ leaded to an increased and dose dependent 3 H-incorporation by the oxidized protein. The production of oxidative damage by IP/Cu2+ was accompanied by marked BSA fragmentation, detected by SDS-polyacrylamide gel dependent (25-400μM IP) des appearance of the original BSA band and appearance of smaller fragments spread in the gel, when incubation has been done in the presence of 100μM Cu2+. These results suggest that copper-catalysed oxidative degradation of proteins induced by catecholamines might be critically involved in the toxic action of these molecules

  15. Chaperone-Mediated Autophagy Targets IFNAR1 for Lysosomal Degradation in Free Fatty Acid Treated HCV Cell Culture.

    Directory of Open Access Journals (Sweden)

    Ramazan Kurt

    Full Text Available Hepatic steatosis is a risk factor for both liver disease progression and an impaired response to interferon alpha (IFN-α-based combination therapy in chronic hepatitis C virus (HCV infection. Previously, we reported that free fatty acid (FFA-treated HCV cell culture induces hepatocellular steatosis and impairs the expression of interferon alpha receptor-1 (IFNAR1, which is why the antiviral activity of IFN-α against HCV is impaired.To investigate the molecular mechanism by which IFNAR1 expression is impaired in HCV cell culture with or without free fatty acid-treatment.HCV-infected Huh 7.5 cells were cultured with or without a mixture of saturated (palmitate and unsaturated (oleate long-chain free fatty acids (FFA. Intracytoplasmic fat accumulation in HCV-infected culture was visualized by oil red staining. Clearance of HCV in FFA cell culture treated with type I IFN (IFN-α and Type III IFN (IFN-λ was determined by Renilla luciferase activity, and the expression of HCV core was determined by immunostaining. Activation of Jak-Stat signaling in the FFA-treated HCV culture by IFN-α alone and IFN-λ alone was examined by Western blot analysis and confocal microscopy. Lysosomal degradation of IFNAR1 by chaperone-mediated autophagy (CMA in the FFA-treated HCV cell culture model was investigated.FFA treatment induced dose-dependent hepatocellular steatosis and lipid droplet accumulation in HCV-infected Huh-7.5 cells. FFA treatment of infected culture increased HCV replication in a concentration-dependent manner. Intracellular lipid accumulation led to reduced Stat phosphorylation and nuclear translocation, causing an impaired IFN-α antiviral response and HCV clearance. Type III IFN (IFN-λ, which binds to a separate receptor, induces Stat phosphorylation, and nuclear translocation as well as antiviral clearance in FFA-treated HCV cell culture. We show here that the HCV-induced autophagy response is increased in FFA-treated cell culture

  16. Development and validation of an enzyme-linked immunosorbent assay for the quantification of a specific MMP-9 mediated degradation fragment of type III collagen--A novel biomarker of atherosclerotic plaque remodeling

    DEFF Research Database (Denmark)

    Barascuk, Natasha; Vassiliadis, Efstathios; Larsen, Lise;

    2011-01-01

    Degradation of collagen in the arterial wall by matrix metalloproteinases is the hallmark of atherosclerosis. We have developed an ELISA for the quantification of type III collagen degradation mediated by MMP-9 in urine....

  17. Interference of c-FLIP by siRNA in treating gallbladder cancer%siRNA干扰c-FLIP表达治疗胆囊癌的实验研究

    Institute of Scientific and Technical Information of China (English)

    宗华杰; 殷保兵; 陈进宏; 马保金; 蔡端; 何祥火

    2009-01-01

    Objective To investigate the expression of c-FLIP in gallbladder cancer and explore the effect of siRNA(small interfering RNA) to interfere expression of c-FLIP on gallbladder cancer cell line. Methods The expression of c-FLIP was detected by immunohistochemieal method in 35 ca-ses of gallbladder cancer compared with 10 cases of normal gallbladder tissue and 10 cases of gallblad-der adenoma. After being interfered by RNAi of c-FLIP, cell viability was measured by CCK-8 meth-od, morphological changes observed through phase-microscopy and apoptosis detected by flow cytome-try. Results The positive expression of e-FLIP in gallbladder cancer tissues was significantly higher than that in normal gallbladder tissues(P<0.05) and gallbladder adenoma tissues(P<0. 05). After being interfered by RNAi of c-FLIP, cell growth of gallbladder cancer cell line SGC-996 was markedly inhibited. Either in phase-microscopy or in flow eytometry, the proportion of apoptosis in samples treated with RNAi of c-FliP for 24 hours was notablely increased as compared with those untreated samples(P<0.05). Conclusion Targeted therapy of RNAi of c-FLIP might be a promising method to treat gallbladder cancer.%目的 检测c-FLIP在胆囊癌组织中的表达,探讨siRNA(small interfering RNA)干扰胆囊癌细胞c-FLIP表达后对细胞生长的影响.方法 用免疫组化法检测10例正常胆囊组织,10例胆囊腺瘤和35例胆囊癌组织中c-FLIP的表达;siRNA干扰c-FLIP表达后,通过生长曲线测定、倒置相差显微镜检查和流式细胞仪检测细胞生长状况.结果 在胆囊癌组织中,c-FLIP的表达明显高于在胆囊腺瘤(P<0.05)和正常胆囊组织中的表达(P<0.05);siRNA干扰c-FLIP表达后,胆囊癌细胞株SGC-996的生长明显受到抑制,倒置相差显微镜检查发现,干扰后细胞凋亡细胞比例明显增加,流式细胞仪的检查发现干扰后细胞凋亡比例与对照组相比明显上升(P<0.05).结论 siRNA干扰c-FLIP表达的靶向治疗

  18. MdmX Protects p53 from Mdm2-Mediated Degradation

    OpenAIRE

    Jackson, Mark W.; Berberich, Steven J.

    2000-01-01

    The p53 tumor suppressor protein is stabilized in response to cellular stress, resulting in activation of genes responsible for either cell cycle arrest or apoptosis. The cellular pathway for releasing normal cells from p53-dependent cell cycle arrest involves the Mdm2 protein. Recently, a p53-binding protein with homology to Mdm2 was identified and called MdmX. Like Mdm2, MdmX is able to bind p53 and inhibit p53 transactivation; however, the ability of MdmX to degrade p53 has yet to be exami...

  19. Cullin 3 mediates SRC-3 ubiquitination and degradation to control the retinoic acid response

    OpenAIRE

    Ferry, Christine; Gaouar, Samia; Fischer, Benoit; Boeglin, Marcel; Paul, Nicodeme; Samarut, Eric; Piskunov, Aleksandr; Pankotai-Bodo, Gabriella; Brino, Laurent; Rochette-Egly, Cecile

    2011-01-01

    SRC-3 is an important coactivator of nuclear receptors including the retinoic acid (RA) receptor α. Most of SRC-3 functions are facilitated by changes in the posttranslational code of the protein that involves mainly phosphorylation and ubiquitination. We recently reported that SRC-3 is degraded by the proteasome in response to RA. Here, by using an RNAi E3-ubiquitin ligase entry screen, we identified CUL-3 and RBX1 as components of the E3 ubiquitin ligase involved in the RA-induced ubiquitin...

  20. Identification and characterization of integron mediated antibiotic resistance in pentachlorophenol degrading bacterium isolated from the chemostat

    Institute of Scientific and Technical Information of China (English)

    SHARMA Ashwani; THAKUR Indu Shekhar

    2009-01-01

    A bacterial consortium was developed by continuous enrichment of microbial population isolated from sediment core of pulp and paper mill effluent in mineral salts medium (MSM) supplemented with pentachlorophenol (PCP) as sole source of carbon and energy in the chemostat.The consortia contained three bacterial strains.They were identified as Escherichia coli,Pseudomonas aeruginosa and Acinetobacter sp.by 16S rRNA gene sequence analysis.Acinetobacter sp.readily degraded PCP through the formation of tetrachloro-p-hydroquinone (TecH),2-chloro-1,4-benzenediol and products of ortho ring cleavage detected by Gas Chromatograph/Mass Spectrometer μgC-MS).Out of the three acclimated PCP degrading bacterial strains only one strain,Acinetobacter sp.showed the presence of integron gene cassette as a marker of its stability and antibiotic resistance.The strain possessed a 4.17 kb amplicon with 22 ORF's.The plasmid isolated from the Acinetobacter sp.was subjected to shotgun cloning through restriction digestion by BamHI,HindIII and SalI,ligated to pUC19 vector and transformed into E.coli XLBlue1α,and finally selected on MSM containing PCP as sole source of carbon and energy with ampicillin as antibiotic marker.DNA sequence analysis of recombinant clones indicated homology with integron gene cassette and multiple antibiotic resistance genes.

  1. Anti-diabetic activity of insulin-degrading enzyme inhibitors mediated by multiple hormones.

    Science.gov (United States)

    Maianti, Juan Pablo; McFedries, Amanda; Foda, Zachariah H; Kleiner, Ralph E; Du, Xiu Quan; Leissring, Malcolm A; Tang, Wei-Jen; Charron, Maureen J; Seeliger, Markus A; Saghatelian, Alan; Liu, David R

    2014-07-01

    Despite decades of speculation that inhibiting endogenous insulin degradation might treat type-2 diabetes, and the identification of IDE (insulin-degrading enzyme) as a diabetes susceptibility gene, the relationship between the activity of the zinc metalloprotein IDE and glucose homeostasis remains unclear. Although Ide(-/-) mice have elevated insulin levels, they exhibit impaired, rather than improved, glucose tolerance that may arise from compensatory insulin signalling dysfunction. IDE inhibitors that are active in vivo are therefore needed to elucidate IDE's physiological roles and to determine its potential to serve as a target for the treatment of diabetes. Here we report the discovery of a physiologically active IDE inhibitor identified from a DNA-templated macrocycle library. An X-ray structure of the macrocycle bound to IDE reveals that it engages a binding pocket away from the catalytic site, which explains its remarkable selectivity. Treatment of lean and obese mice with this inhibitor shows that IDE regulates the abundance and signalling of glucagon and amylin, in addition to that of insulin. Under physiological conditions that augment insulin and amylin levels, such as oral glucose administration, acute IDE inhibition leads to substantially improved glucose tolerance and slower gastric emptying. These findings demonstrate the feasibility of modulating IDE activity as a new therapeutic strategy to treat type-2 diabetes and expand our understanding of the roles of IDE in glucose and hormone regulation. PMID:24847884

  2. Severe acute respiratory syndrome coronavirus protein 6 mediates ubiquitin-dependent proteosomal degradation of N-Myc(and STAT) interactor

    Institute of Scientific and Technical Information of China (English)

    Weijia; Cheng; Shiyou; Chen; Ruiling; Li; Yu; Chen; Min; Wang; Deyin; Guo

    2015-01-01

    Severe acute respiratory syndrome coronavirus(SARS-Co V) encodes eight accessory proteins, the functions of which are not yet fully understood. SARS-Co V protein 6(P6) is one of the previously studied accessory proteins that have been documented to enhance viral replication and suppress host interferon(IFN) signaling pathways. Through yeast two-hybrid screening, we identified eight potential cellular P6-interacting proteins from a human spleen c DNA library. For further investigation, we targeted the IFN signaling pathway-mediating protein, N-Myc(and STAT) interactor(Nmi). Its interaction with P6 was confirmed within cells. The results showed that P6 can promote the ubiquitin-dependent proteosomal degradation of Nmi. This study revealed a new mechanism of SARS-Co V P6 in limiting the IFN signaling to promote SARS-Co V survival in host cells.

  3. Acetylation Targets the M2 Isoform of Pyruvate Kinase for Degradation through Chaperone-Mediated Autophagy and Promotes Tumor Growth

    Science.gov (United States)

    Lv, Lei; Li, Dong; Zhao, Di; Lin, Ruiting; Chu, Yajing; Zhang, Heng; Zha, Zhengyu; Liu, Ying; Li, Zi; Xu, Yanping; Wang, Gang; Huang, Yiran; Xiong, Yue; Guan, Kun-Liang; Lei, Qun-Ying

    2016-01-01

    SUMMARY Most tumor cells take up more glucose than normal cells but metabolize glucose via glycolysis even in the presence of normal levels of oxygen, a phenomenon known as the Warburg effect. Tumor cells commonly express the embryonic M2 isoform of pyruvate kinase (PKM2) that may contribute to the metabolism shift from oxidative phosphorylation to aerobic glycolysis and tumorigenesis. Here we show that PKM2 is acetylated on lysine 305 and that this acetylation is stimulated by high glucose concentration. PKM2 K305 acetylation decreases PKM2 enzyme activity and promotes its lysosomal-dependent degradation via chaperone-mediated autophagy (CMA). Acetylation increases PKM2 interaction with HSC70, a chaperone for CMA, and association with lysosomes. Ectopic expression of an acetylation mimetic K305Q mutant accumulates glycolytic intermediates and promotes cell proliferation and tumor growth. These results reveal an acetylation regulation of pyruvate kinase and the link between lysine acetylation and CMA. PMID:21700219

  4. CDK11p58 represses vitamin D receptor-mediated transcriptional activation through promoting its ubiquitin-proteasome degradation

    International Nuclear Information System (INIS)

    Vitamin D receptor (VDR) is a member of the nuclear receptor superfamily and regulates transcription of target genes. In this study, we identified CDK11p58 as a novel protein involved in the regulation of VDR. CDK11p58, a member of the large family of p34cdc2-related kinases, is associated with cell cycle progression, tumorigenesis, and apoptotic signaling. Our study demonstrated that CDK11p58 interacted with VDR and repressed VDR-dependent transcriptional activation. Furthermore, overexpression of CDK11p58 decreased the stability of VDR through promoting its ubiquitin-proteasome-mediated degradation. Taken together, these results suggest that CDK11p58 is involved in the negative regulation of VDR.

  5. PIAS1-mediated sumoylation promotes STUbL-dependent proteasomal degradation of the human telomeric protein TRF2.

    Science.gov (United States)

    Her, Joonyoung; Jeong, Yu Young; Chung, In Kwon

    2015-10-24

    The human telomeric protein TRF2 protects chromosome ends by facilitating their organization into the protective capping structure. Here we show that the stability of TRF2 is regulated via modification by the small ubiquitin-like modifiers (SUMO). TRF2 specifically interacts with and is sumoylated by PIAS1 in mammalian cells. The proteasome inhibitor stabilizes SUMO-conjugated TRF2 without affecting the level of unmodified TRF2, suggesting that SUMO conjugation is required for proteasomal degradation of TRF2. We also show that RNF4, a mammalian SUMO-targeted ubiquitin ligase, interacts with TRF2 in a SUMO-dependent manner and preferentially targets SUMO-conjugated TRF2 for ubiquitination. Collectively, our data demonstrate that the PIAS1-mediated sumoylation status of TRF2 serves as a molecular switch that controls the level of TRF2 at telomeres. PMID:26450775

  6. CDK11{sup p58} represses vitamin D receptor-mediated transcriptional activation through promoting its ubiquitin-proteasome degradation

    Energy Technology Data Exchange (ETDEWEB)

    Chi, Yayun; Hong, Yi; Zong, Hongliang; Wang, Yanlin; Zou, Weiying; Yang, Junwu; Kong, Xiangfei; Yun, Xiaojing [Gene Research Center, Shanghai Medical College and Institutes of Biomedical, Shanghai 200032 (China); Gu, Jianxin, E-mail: jxgu@shmu.edu.cn [Gene Research Center, Shanghai Medical College and Institutes of Biomedical, Shanghai 200032 (China)

    2009-08-28

    Vitamin D receptor (VDR) is a member of the nuclear receptor superfamily and regulates transcription of target genes. In this study, we identified CDK11{sup p58} as a novel protein involved in the regulation of VDR. CDK11{sup p58}, a member of the large family of p34cdc2-related kinases, is associated with cell cycle progression, tumorigenesis, and apoptotic signaling. Our study demonstrated that CDK11{sup p58} interacted with VDR and repressed VDR-dependent transcriptional activation. Furthermore, overexpression of CDK11{sup p58} decreased the stability of VDR through promoting its ubiquitin-proteasome-mediated degradation. Taken together, these results suggest that CDK11{sup p58} is involved in the negative regulation of VDR.

  7. Proteasomal degradation of preemptive quality control (pQC) substrates is mediated by an AIRAPL-p97 complex.

    Science.gov (United States)

    Braunstein, Ilana; Zach, Lolita; Allan, Susanne; Kalies, Kai-Uwe; Stanhill, Ariel

    2015-11-01

    The initial folding of secreted proteins occurs in the ER lumen, which contains specific chaperones and where posttranslational modifications may occur. Therefore lack of translocation, regardless of entry route or protein identity, is a highly toxic event, as the newly synthesized polypeptide is misfolded and can promiscuously interact with cytosolic factors. Mislocalized proteins bearing a signal sequence that did not successfully translocate through the translocon complex are subjected to a preemptive quality control (pQC) pathway and are degraded by the ubiquitin-proteasome system (UPS). In contrast to UPS-mediated, ER-associated degradation, few components involved in pQC have been identified. Here we demonstrate that on specific translocation inhibition, a p97-AIRAPL complex directly binds and regulates the efficient processing of polyubiquitinated pQC substrates by the UPS. We also demonstrate p97's role in pQC processing of preproinsulin in cases of naturally occurring mutations within the signal sequence of insulin. PMID:26337389

  8. Laccase-syringaldehyde-mediated degradation of trace organic contaminants in an enzymatic membrane reactor: Removal efficiency and effluent toxicity.

    Science.gov (United States)

    Nguyen, Luong N; van de Merwe, Jason P; Hai, Faisal I; Leusch, Frederic D L; Kang, Jinguo; Price, William E; Roddick, Felicity; Magram, Saleh F; Nghiem, Long D

    2016-01-01

    Redox-mediators such as syringaldehyde (SA) can improve laccase-catalyzed degradation of trace organic contaminants (TrOCs) but may increase effluent toxicity. The degradation performance of 14 phenolic and 17 non-phenolic TrOCs by a continuous flow enzymatic membrane reactor (EMR) at different TrOC and SA loadings was assessed. A specific emphasis was placed on the investigation of the toxicity of the enzyme (laccase), SA, TrOCs and the treated effluent. Batch tests demonstrated significant individual and interactive toxicity of the laccase and SA preparations. Reduced removal of resistant TrOCs by the EMR was observed for dosages over 50μg/L. SA addition at a concentration of 10μM significantly improved TrOC removal, but no removal improvement was observed at the elevated SA concentrations of 50 and 100μM. The treated effluent showed significant toxicity at SA concentrations beyond 10μM, providing further evidence that higher dosage of SA must be avoided. PMID:26519700

  9. Atypical ubiquitination by E3 ligase WWP1 inhibits the proteasome-mediated degradation of mutant huntingtin.

    Science.gov (United States)

    Lin, Li; Jin, Zhenzhen; Tan, Huiping; Xu, Qiaoqiao; Peng, Ting; Li, He

    2016-07-15

    Huntington's disease (HD) is caused by the expansion of CAG trinucleotide repeats in exon 1 of HD gene encoding huntingtin (Htt), which is characterized by aggregation and formation of mutant Htt containing expanded polyglutamine (polyQ) repeats. Dysfunction of the ubiquitin-proteasome system (UPS) plays a critical role in the pathogenesis of HD. As the linkage mediator between ubiquitin and specific target proteins, E3 ubiquitin ligases have been suggested to be involved in mHtt degradation and HD pathology. However, the potential involvement of the E3 ligase WWP1 in HD has not been explored. The present study determined whether WWP1 is involved in the development of HD in both in vivo and in vitro models. The results showed that in contrast to several other E3 ligases, expression of WWP1 is enhanced in mice and N2a cells expressing mutant Htt (160Q) and co-localized with mHtt protein aggregates. In addition, expression of WWP1 positively regulates mutan Htt levels, aggregate formation, and cell toxicity. Further analysis revealed that WWP1 ubiquitinated mHtt at an atypical position of Lys-63, which may have inhibited degradation of mutant Htt through the ubiquitin-proteasome pathway. In conclusion, these results suggested that the E3 ligase WWP1 is involved in the pathogenesis of HD; therefore, it may be a novel target for therapeutic intervention. PMID:27107943

  10. Measurement of matrix metalloproteinase 9-mediated Collagen type III degradation fragment as a marker of skin fibrosis

    Directory of Open Access Journals (Sweden)

    Larsen Lise

    2011-03-01

    Full Text Available Abstract Background The current study utilized a Bleomycin-induced model of skin fibrosis to investigate the neo-epitope CO3-610 (KNGETGPQGP, a fragment of collagen III released during matrix metalloproteinase-9 (MMP9 degradation of the protein, we have previously described as a novel biomarker for liver fibrosis. The aim was to investigate CO3-610 levels in another well characterised model of fibrosis, to better describe the biomarker in relation to additional fibrotic pathologies. Methods Skin fibrosis was induced by daily injections of Bleomycin to a total of 52 female C3 H mice, while control mice (n = 28 were treated with phosphate buffered saline (PBS, for 2, 4, 6 or 8 weeks. Skin fibrosis was evaluated using Visiopharm software on Sirius-red stained skin sections. Urine ELISA assays and creatinine corrections were performed to measure CO3-610 levels. Results CO3-610 levels were significantly higher in Bleomycin-treated vs. PBS-treated mice at each time point of termination. The mean increases were: 59.2%, P Conclusion Increased levels in mouse urine of the MMP-9 mediated collagen III degradation fragment CO3-610 were correlated with skin fibrosis progression, suggesting that CO3-610 may be a potential positive biomarker to study the pathogenesis of skin fibrosis in mice.

  11. TSGΔ154-1054 splice variant increases TSG101 oncogenicity by inhibiting its E3-ligase-mediated proteasomal degradation

    Science.gov (United States)

    Weng, Pei-Lun; Yeh, Te-Huei

    2016-01-01

    Tumor susceptibility gene 101 (TSG101) elicits an array of cellular functions, including promoting cytokinesis, cell cycle progression and proliferation, as well as facilitating endosomal trafficking and viral budding. TSG101 protein is highly and aberrantly expressed in various human cancers. Specifically, a TSG101 splicing variant missing nucleotides 154 to 1054 (TSGΔ154-1054), which is linked to progressive tumor-stage and metastasis, has puzzled investigators for more than a decade. TSG101-associated E3 ligase (Tal)- and MDM2-mediated proteasomal degradation are the two major routes for posttranslational regulation of the total amount of TSG101. We reveal that overabundance of TSG101 results from TSGΔ154-1054 stabilizing the TSG101 protein by competitively binding to Tal, but not MDM2, thereby perturbing the Tal interaction with TSG101 and impeding subsequent polyubiquitination and proteasomal degradation of TSG101. TSGΔ154-1054 therefore specifically enhances TSG101-stimulated cell proliferation, clonogenicity, and tumor growth in nude mice. This finding shows the functional significance of TSGΔ154-1054 in preventing the ubiquitin-proteasome proteolysis of TSG101, which increases tumor malignancy and hints at its potential as a therapeutic target in cancer treatment. PMID:26811492

  12. β-TrCP-mediated ubiquitination and degradation of liver-enriched transcription factor CREB-H

    Science.gov (United States)

    Cheng, Yun; Gao, Wei-Wei; Tang, Hei-Man Vincent; Deng, Jian-Jun; Wong, Chi-Ming; Chan, Chi-Ping; Jin, Dong-Yan

    2016-01-01

    CREB-H is an endoplasmic reticulum-resident bZIP transcription factor which critically regulates lipid homeostasis and gluconeogenesis in the liver. CREB-H is proteolytically activated by regulated intramembrane proteolysis to generate a C-terminally truncated form known as CREB-H-ΔTC, which translocates to the nucleus to activate target gene expression. CREB-H-ΔTC is a fast turnover protein but the mechanism governing its destruction was not well understood. In this study, we report on β-TrCP-dependent ubiquitination and proteasomal degradation of CREB-H-ΔTC. The degradation of CREB-H-ΔTC was mediated by lysine 48-linked polyubiquitination and could be inhibited by proteasome inhibitor. CREB-H-ΔTC physically interacted with β-TrCP, a substrate recognition subunit of the SCFβ-TrCP E3 ubiquitin ligase. Forced expression of β-TrCP increased the polyubiquitination and decreased the stability of CREB-H-ΔTC, whereas knockdown of β-TrCP had the opposite effect. An evolutionarily conserved sequence, SDSGIS, was identified in CREB-H-ΔTC, which functioned as the β-TrCP-binding motif. CREB-H-ΔTC lacking this motif was stabilized and resistant to β-TrCP-induced polyubiquitination. This motif was a phosphodegron and its phosphorylation was required for β-TrCP recognition. Furthermore, two inhibitory phosphorylation sites close to the phosphodegron were identified. Taken together, our work revealed a new intracellular signaling pathway that controls ubiquitination and degradation of the active form of CREB-H transcription factor. PMID:27029215

  13. M2-like macrophages are responsible for collagen degradation through a mannose receptor-mediated pathway

    DEFF Research Database (Denmark)

    Madsen, Daniel H; Leonard, Daniel; Masedunskas, Andrius;

    2013-01-01

    Tissue remodeling processes critically depend on the timely removal and remodeling of preexisting collagen scaffolds. Nevertheless, many aspects related to the turnover of this abundant extracellular matrix component in vivo are still incompletely understood. We therefore took advantage of recent...... advances in optical imaging to develop an assay to visualize collagen turnover in situ and identify cell types and molecules involved in this process. Collagen introduced into the dermis of mice underwent cellular endocytosis in a partially matrix metalloproteinase-dependent manner and was subsequently...... routed to lysosomes for complete degradation. Collagen uptake was predominantly executed by a quantitatively minor population of M2-like macrophages, whereas more abundant Col1a1-expressing fibroblasts and Cx3cr1-expressing macrophages internalized collagen at lower levels. Genetic ablation of the...

  14. Sap transporter mediated import and subsequent degradation of antimicrobial peptides in Haemophilus.

    Directory of Open Access Journals (Sweden)

    Catherine L Shelton

    2011-11-01

    Full Text Available Antimicrobial peptides (AMPs contribute to host innate immune defense and are a critical component to control bacterial infection. Nontypeable Haemophilus influenzae (NTHI is a commensal inhabitant of the human nasopharyngeal mucosa, yet is commonly associated with opportunistic infections of the upper and lower respiratory tracts. An important aspect of NTHI virulence is the ability to avert bactericidal effects of host-derived antimicrobial peptides (AMPs. The Sap (sensitivity to antimicrobial peptides ABC transporter equips NTHI to resist AMPs, although the mechanism of this resistance has remained undefined. We previously determined that the periplasmic binding protein SapA bound AMPs and was required for NTHI virulence in vivo. We now demonstrate, by antibody-mediated neutralization of AMP in vivo, that SapA functions to directly counter AMP lethality during NTHI infection. We hypothesized that SapA would deliver AMPs to the Sap inner membrane complex for transport into the bacterial cytoplasm. We observed that AMPs localize to the bacterial cytoplasm of the parental NTHI strain and were susceptible to cytoplasmic peptidase activity. In striking contrast, AMPs accumulated in the periplasm of bacteria lacking a functional Sap permease complex. These data support a mechanism of Sap mediated import of AMPs, a novel strategy to reduce periplasmic and inner membrane accumulation of these host defense peptides.

  15. Field solar degradation of pesticides and emerging water contaminants mediated by polymer films containing titanium and iron oxide with synergistic heterogeneous photocatalytic activity at neutral pH.

    Science.gov (United States)

    Mazille, F; Schoettl, T; Klamerth, N; Malato, S; Pulgarin, C

    2010-05-01

    Photocatalytic degradation of phenol, nalidixic acid, mixture of pesticides, and another of emerging contaminants in water was mediated by TiO(2) and iron oxide immobilized on functionalized polyvinyl fluoride films (PVF(f)-TiO(2)-Fe oxide) in a compound parabolic collector (CPC) solar photoreactor. During degradation, little iron leaching (<0.2mgL(-1)) was observed. Phenol was efficiently degraded and mineralized at operational pH<5 and nalidixic acid degradation was complete even at pH 7, but mineralization stopped at 35%. Pesticide mixture was slowly degraded (50%) after 150min of irradiation. Degradation of the emergent contaminant mixture was successful for eight compounds and less efficient for six other compounds. The significant reactivity differences between tested compounds were assigned to the differences in structure namely that the presence of complexing or chelating groups enhanced the rates. PVF(f)-TiO(2)-Fe oxide photoactivity gradually increased during 20 days of experiments. X-ray photoelectron spectroscopy (XPS) measurements revealed significant changes on the catalyst surface. These analyses confirm that during photocatalysis mediated by PVF(f)-TiO(2)-Fe oxide, some iron leaching led to enlargement of the TiO(2) surface exposed to light, increasing its synergy with iron oxides and leading to enhanced pollutant degradation. PMID:20362319

  16. Hesperidin, A Popular Antioxidant Inhibits Melanogenesis via Erk1/2 Mediated MITF Degradation

    Directory of Open Access Journals (Sweden)

    Heun Joo Lee

    2015-08-01

    Full Text Available Regulation of melanogenesis has been the focus of treatment for hyperpigmentary skin disorders. Although hesperidin is one of the most well-known, naturally occurring flavonoids with antioxidant and anti-inflammatory effect, its anti-melanogenic effect is not known. The present study aims to determine the anti-melanogenic effect of hespiridin as well as its underlying molecular mechanisms. Melanin contents were measured in normal human melanocytes and B16F10 melanoma cells. Protein and mRNA levels of tyrosinase, microphthalmia-associated transcription factor (MITF, tyrosinase related protein-1 (TRP-1 and TRP-2 were determined. Melanogenesis-regulating signals were examined. In results, hesperidin strongly inhibited melanin synthesis and tyrosinase activity. Hesperidin decreased tyrosinase, TRP-1, and TRP-2 protein expression but increased phospho-extracellular signal-regulated kinase 1/2 (p-Erk1/2 expression. Specific inhibitor of Erk1/2 or proteasome inhibitor reversed the inhibition of melanogenesis induced by hesperidin. Taken together, hesperidin, a popular antioxidant, stimulated Erk1/2 phosphorylation which subsequently degraded MITF which resulted in suppression of melanogenic enzymes and melanin synthesis.

  17. Cathepsin D-mediated yolk protein degradation is blocked by acid phosphatase inhibitors.

    Science.gov (United States)

    Fialho, Eliane; Nakamura, Angelica; Juliano, Luiz; Masuda, Hatisaburo; Silva-Neto, Mário A C

    2005-04-15

    Vitellin (VT) is a lipoglycophosphoprotein stored inside the eggs of every oviparous organism during oogenesis. In the blood-sucking bug Rhodnius prolixus, VT is deposited inside growing oocytes together with two acid hydrolases: acid phosphatase (AP) and cathepsin D (CD). Egg fertilization triggers AP activity and VT proteolysis in vivo [Insect Biochem. Mol. Biol. 2002 (32) 847]. Here, we show that CD is the main protease targeting VT proteolysis during egg development. CD activity in total egg homogenates is blocked by the classical aspartyl protease inhibitor, pepstatin A. Surprisingly, AP inhibitors such as NaF, Na+/K+ tartrate, and inorganic phosphate also block VT proteolysis, whereas this effect is not observed when tyrosine phosphatase inhibitors such as vanadate and phenylarsine oxide or an inhibitor of alkaline phosphatases such as levamisole are used in a VT proteolysis assay. NaF concentrations that block isolated AP activity do not affect the activity of partially purified CD. Therefore, a specific repressor of VT proteolysis must be dephosphorylated by AP in vivo. In conclusion, these results demonstrate for the first time that acid hydrolases act cooperatively to promote yolk degradation during egg development in arthropods. PMID:15797237

  18. Regulation of mIκBNS stability through PEST-mediated degradation by proteasome

    International Nuclear Information System (INIS)

    Highlights: • mIκBNS is degraded rapidly by proteasome without ubiquitylation. • N-terminal PEST sequence is responsible for the unstable nature of mIκBNS. • PEST sequence is not critical for nuclear localization of mIκBNS. • There is single bona fide NLS at the C-terminus of mIκBNS. - Abstract: Negative regulatory proteins in a cytokine signaling play a critical role in restricting unwanted excess activation of the signaling pathway. At the same time, negative regulatory proteins need to be removed rapidly from cells to respond properly to the next incoming signal. A nuclear IκB protein called IκBNS is known to inhibit a subset of NF-κB target genes upon its expression by NF-κB activation. Here, we show a mechanism to control the stability of mIκBNS which might be important for cells to prepare the next round signaling. We found that mIκBNS is a short-lived protein of which the stability is controlled by proteasome, independent of ubiquitylation process. We identified that the N-terminal PEST sequence in mIκBNS was critical for the regulation of stability

  19. Highly efficient visible light mediated azo dye degradation through barium titanate decorated reduced graphene oxide sheets

    Science.gov (United States)

    Rastogi, Monisha; Kushwaha, H. S.; Vaish, Rahul

    2016-03-01

    This study investigates BaTiO3 decorated reduced graphene oxide sheets as a potential visible light active catalyst for dye degradation (Rhodamine B). The composites were prepared through conventional hydrothermal synthesis technique using hydrazine as a reducing agent. A number of techniques have been employed to affirm the morphology, composition and photocatalytic properties of the composites; these include UV-visible spectrophotoscopy that assisted in quantifying the concentration difference of Rhodamine B. The phase homogeneity of the composites was examined through x-ray powder diffraction (XRD) and high resolution transmission electron microscopy (HRTEM) was employed to confirm the orientation of the BaTiO3 particles over the reduced graphene oxide sheets. Photoluminescence (PL) emission spectra assisted in determining the surface structure and excited state of the catalyst. Fourier transformed-infrared (FTIR) spectra investigated the vibrations and adsorption peak of the composites, thereby ascertaining the formation of reduced graphene oxide. In addition, diffuse reflectance spectroscopy (DRS) demonstrated an enhanced absorption in the visible region. The experimental investigations revealed that graphene oxide acted as charge collector and simultaneously facilitated surface adsorption and photo-sensitization. It could be deduced that BaTiO3-reduced graphene oxide composites are of significant interest the field of water purification through solar photocatalysis. [Figure not available: see fulltext.

  20. SRG3/mBAF155 stabilizes the SWI/SNF-like BAF complex by blocking CHFR mediated ubiquitination and degradation of its major components

    International Nuclear Information System (INIS)

    Highlights: ► CHFR mediates the ubiquitination of the major components of the SWI/SNF complex. ► CHFR mediated-ubiquitination induces the degradation of the major components. ► SRG3 stabilizes the SWI/SNF-like BAF complex by blocking the CHFR activity. -- Abstract: The murine SWI/SNF-like BAF complex is an ATP-dependent chromatin remodeling complex that functions as a transcriptional regulator in cell proliferation, differentiation and development. The SWI/SNF-like BAF complex consists of several components including core subunits such as BRG1, BAF155/SRG3, BAF47/SNF5/INI1, and BAF170. We have previously shown that the interaction between SRG3/mBAF155 and other components of the complex stabilizes them by attenuating their proteasomal degradation. However, it has not been known how the major components of the SWI/SNF-like BAF complex such as BRG1, SNF5, and BAF60a are targeted for the ubiquitination and degradation, and how SRG3/mBAF155 protects them from the degradation process. Here we report that CHFR interacts with BRG1, SNF5, and BAF60a of the SWI/SNF-like BAF complex and ubiquitinates them to target for degradation through a proteasome-mediated pathway, and that SRG3/mBAF155 stabilizes these components by blocking their interaction with CHFR.

  1. c -FLIP increases the ability of proliferation and invasion via suppressing the autophagy in hepatocellular carcinoma%c-FLIP 通过抑制自噬促进肝癌细胞增殖和侵袭的机制

    Institute of Scientific and Technical Information of China (English)

    陈冲; 雷世雄; 铁娅滕; 唐海利; 杨振宇; 周龙志; 李燕; 杜锡林

    2016-01-01

    目的:研究凋亡抑制蛋白 c -FLIP 对肝癌细胞自噬及恶性生物学行为的影响。方法:在低糖条件下通过干扰 c -FLIP 的表达,明确 c -FLIP 对低糖诱导肝癌细胞自噬的影响。Transwell、细胞划痕、增殖实验及裸鼠荷瘤等方法分析肝癌细胞恶性表型。结果:干涉 c -FLIP 后,肝癌细胞自噬水平明显上升;c -FLIP 干涉组肝癌细胞增殖、侵袭、运动能力均降低,差异具有统计学意义;与对照组相比,c -FLIP 干涉组荷瘤裸鼠存活率上升。结论:c -FLIP 抑制低糖诱导的肝癌细胞自噬发生,促进肝癌的增殖和侵袭能力,提示 c -FLIP 可能通过调节肝癌细胞自噬在肝癌的发生发展过程中发挥着重要作用。%Objective:To investigate the effect of cellular caspase 8(FLICE)-like inhibitory protein(c -FLIP) on the autophagy activity and biological characteristics in HepG2 cells.Methods:Imitating the low carbohydrates en-vironment of hepatic carcinoma,we inhibited the expression of c -FLIP to set a treatment group and the other one was as control.To observe the expression of autophagy associated protein LC3 and p62,the formation of autophagosome by immunofluorescence and transmission electron microscope,detect the malignancy of hepatocyte HepG2 by the tran-swell,wound healing,and cell proliferation assay.We also analyzed the survival rate of nude mice to evaluate the ma-lignancy of the two groups.Results:The expression of LC3 and p62 and the number of autophagosome increased obvi-ously over time after suppressing c -FLIP.The ability of proliferation,invasive and migration of the treatment group decreased severally.The survival rate of nude mice in treatment group was higher than the control(P <0.05).Con-clusion:The expression of c -FLIP could apparently suppress the autophagy activity and efficiently enhance the ma-lignancy of HepG2,indicating that c -FLIP has an important role in the occurrence and

  2. Dysregulation of protein degradation pathways may mediate the liver injury and phospholipidosis associated with a cationic amphiphilic antibiotic drug

    Energy Technology Data Exchange (ETDEWEB)

    Mosedale, Merrie [Hamner-University of North Carolina Institute for Drug Safety Sciences, The Hamner Institutes for Health Sciences, Research Triangle Park, NC 27709 (United States); Wu, Hong [Drug Safety Research and Development, Pfizer Global Research and Development, Groton, CT06340 (United States); Kurtz, C. Lisa [Hamner-University of North Carolina Institute for Drug Safety Sciences, The Hamner Institutes for Health Sciences, Research Triangle Park, NC 27709 (United States); Schmidt, Stephen P. [Drug Safety Research and Development, Pfizer Global Research and Development, Groton, CT06340 (United States); Adkins, Karissa, E-mail: Karissa.Adkins@pfizer.com [Drug Safety Research and Development, Pfizer Global Research and Development, Groton, CT06340 (United States); Harrill, Alison H. [Hamner-University of North Carolina Institute for Drug Safety Sciences, The Hamner Institutes for Health Sciences, Research Triangle Park, NC 27709 (United States); University of Arkansas for Medical Sciences, Little Rock, AR72205 (United States)

    2014-10-01

    A large number of antibiotics are known to cause drug-induced liver injury in the clinic; however, interpreting clinical risk is not straightforward owing to a lack of predictivity of the toxicity by standard preclinical species and a poor understanding of the mechanisms of toxicity. An example is PF-04287881, a novel ketolide antibiotic that caused elevations in liver function tests in Phase I clinical studies. In this study, a mouse diversity panel (MDP), comprised of 34 genetically diverse, inbred mouse strains, was utilized to model the toxicity observed with PF-04287881 treatment and investigate potential mechanisms that may mediate the liver response. Significant elevations in serum alanine aminotransferase (ALT) levels in PF-04287881-treated animals relative to vehicle-treated controls were observed in the majority (88%) of strains tested following a seven day exposure. The average fold elevation in ALT varied by genetic background and correlated with microscopic findings of hepatocellular hypertrophy, hepatocellular single cell necrosis, and Kupffer cell vacuolation (confirmed as phospholipidosis) in the liver. Global liver mRNA expression was evaluated in a subset of four strains to identify transcript and pathway differences that distinguish susceptible mice from resistant mice in the context of PF-04287881 treatment. The protein ubiquitination pathway was highly enriched among genes associated with PF-04287881-induced hepatocellular necrosis. Expression changes associated with PF-04287881-induced phospholipidosis included genes involved in drug transport, phospholipid metabolism, and lysosomal function. The findings suggest that perturbations in genes involved in protein degradation leading to accumulation of oxidized proteins may mediate the liver injury induced by this drug. - Highlights: • Identified susceptible and resistant mouse strains to liver injury induced by a CAD • Liver injury characterized by single cell necrosis, and phospholipidosis

  3. Dysregulation of protein degradation pathways may mediate the liver injury and phospholipidosis associated with a cationic amphiphilic antibiotic drug

    International Nuclear Information System (INIS)

    A large number of antibiotics are known to cause drug-induced liver injury in the clinic; however, interpreting clinical risk is not straightforward owing to a lack of predictivity of the toxicity by standard preclinical species and a poor understanding of the mechanisms of toxicity. An example is PF-04287881, a novel ketolide antibiotic that caused elevations in liver function tests in Phase I clinical studies. In this study, a mouse diversity panel (MDP), comprised of 34 genetically diverse, inbred mouse strains, was utilized to model the toxicity observed with PF-04287881 treatment and investigate potential mechanisms that may mediate the liver response. Significant elevations in serum alanine aminotransferase (ALT) levels in PF-04287881-treated animals relative to vehicle-treated controls were observed in the majority (88%) of strains tested following a seven day exposure. The average fold elevation in ALT varied by genetic background and correlated with microscopic findings of hepatocellular hypertrophy, hepatocellular single cell necrosis, and Kupffer cell vacuolation (confirmed as phospholipidosis) in the liver. Global liver mRNA expression was evaluated in a subset of four strains to identify transcript and pathway differences that distinguish susceptible mice from resistant mice in the context of PF-04287881 treatment. The protein ubiquitination pathway was highly enriched among genes associated with PF-04287881-induced hepatocellular necrosis. Expression changes associated with PF-04287881-induced phospholipidosis included genes involved in drug transport, phospholipid metabolism, and lysosomal function. The findings suggest that perturbations in genes involved in protein degradation leading to accumulation of oxidized proteins may mediate the liver injury induced by this drug. - Highlights: • Identified susceptible and resistant mouse strains to liver injury induced by a CAD • Liver injury characterized by single cell necrosis, and phospholipidosis

  4. The effects of mediator and granular activated carbon addition on degradation of trace organic contaminants by an enzymatic membrane reactor.

    Science.gov (United States)

    Nguyen, Luong N; Hai, Faisal I; Price, William E; Leusch, Frederic D L; Roddick, Felicity; Ngo, Hao H; Guo, Wenshan; Magram, Saleh F; Nghiem, Long D

    2014-09-01

    The removal of four recalcitrant trace organic contaminants (TrOCs), namely carbamazepine, diclofenac, sulfamethoxazole and atrazine by laccase in an enzymatic membrane reactor (EMR) was studied. Laccases are not effective for degrading non-phenolic compounds; nevertheless, 22-55% removal of these four TrOCs was achieved by the laccase EMR. Addition of the redox-mediator syringaldehyde (SA) to the EMR resulted in a notable dose-dependent improvement (15-45%) of TrOC removal affected by inherent TrOC properties and loading rates. However, SA addition resulted in a concomitant increase in the toxicity of the treated effluent. A further 14-25% improvement in aqueous phase removal of the TrOCs was consistently observed following a one-off dosing of 3g/L granular activated carbon (GAC). Mass balance analysis reveals that this improvement was not due solely to adsorption but also enhanced biodegradation. GAC addition also reduced membrane fouling and the SA-induced toxicity of the effluent. PMID:24980029

  5. The role of the ubiquitination–proteasome pathway in breast cancer: Ubiquitin mediated degradation of growth factor receptors in the pathogenesis and treatment of cancer

    International Nuclear Information System (INIS)

    Aberrant activity of growth factor receptors has been implicated in the pathogenesis of a wide variety of malignancies. The negative regulation of signaling by growth factor receptors is mediated in large part by the ubiquitination, internalization, and degradation of the activated receptor. Over the past few years, considerable insight into the mechanisms that control receptor downregulation has been gained. There are also data suggesting that mutations that lead to inhibition of downregulation of growth factor receptors could play a role in the pathogenesis of cancer. Therapies directed at enhancing the degradation of growth factor receptors offer a promising approach to the treatment of malignancies

  6. The role of the ubiquitination–proteasome pathway in breast cancer: Ubiquitin mediated degradation of growth factor receptors in the pathogenesis and treatment of cancer

    OpenAIRE

    Lipkowitz, Stan

    2002-01-01

    Aberrant activity of growth factor receptors has been implicated in the pathogenesis of a wide variety of malignancies. The negative regulation of signaling by growth factor receptors is mediated in large part by the ubiquitination, internalization, and degradation of the activated receptor. Over the past few years, considerable insight into the mechanisms that control receptor downregulation has been gained. There are also data suggesting that mutations that lead to inhibition of downregulat...

  7. Small Molecule-Based Promotion of PKCα-Mediated β-Catenin Degradation Suppresses the Proliferation of CRT-Positive Cancer Cells

    OpenAIRE

    Gwak, Jungsug; Lee, Jee-Hyun; Chung, Young-Hwa; Song, Gyu-Yong; Oh, Sangtaek

    2012-01-01

    Aberrant accumulation of intracellular β-catenin is a well recognized characteristic of several cancers, including prostate, colon, and liver cancers, and is a potential target for development of anticancer therapeutics. Here, we used cell-based small molecule screening to identify CGK062 as an inhibitor of Wnt/β-catenin signaling. CGK062 promoted protein kinase Cα (PKCα)-mediated phosphorylation of β-catenin at Ser33/Ser37, marking it for proteasomal degradation. This reduced intracellular β...

  8. cIAP2 represses IKKα/β-mediated activation of MDM2 to prevent p53 degradation.

    Science.gov (United States)

    Lau, Rosanna; Niu, Min Ying; Pratt, M A Christine

    2012-11-01

    Cellular inhibitor of apoptosis proteins (cIAP1 and cIAP2) function to prevent apoptosis and are often overexpressed in various cancers. However, mutations in cIAP1/2 can activate the alternative NFκB pathway through IκBα-kinase-α (IKKα) and are associated with hematopoetic malignancies. In the current study, we found that knockdown of cIAP2 in human mammary epithelial cells resulted in activation of MDM2 through increased SUMOylation and profound reduction of the pool of MDM2 not phosphorylated at Ser166. cIAP2 siRNA markedly decreased p53 levels, which were rescued by addition of the MDM2 inhibitor, Nutlin3a. An IAP antagonist, which induces cIAP degradation, transiently increased MDM2 mRNA. Simultaneous transfection of siRNA for cIAP2 and IKKα reduced MDM2 protein, while expression of a kinase-dead IKKβ strongly increased non-Ser166 P-MDM2. Inhibition of either IKKα or -β partially rescued p53 levels, while concomitant IKKα/β inhibition fully rescued p53 after cIAP2 knockdown. Surprisingly, IKKα knockdown alone increased SUMO-MDM2, suggesting that in the absence of activation, IKKα can prevent MDM2 SUMOylation. cIAP2 knockdown disrupted the interaction between the MDM2 SUMO ligase, PIAS1 and IKKα. Partial knockdown of cIAP2 cooperated with (V12) H-ras-transfected mammary epithelial cells to enhance colony formation. In summary, our data identify a novel role for cIAP2 in maintaining wild-type p53 levels by preventing both an NFκB-mediated increase and IKKα/-β-dependent transcriptional and post-translational modifications of MDM2. Thus, mutations or reductions in cIAP2 could contribute to cancer promotion, in part, through downregulation of p53. PMID:23032264

  9. Effect of Bucillamine on Free-Radical-Mediated Degradation of High-Molar-Mass Hyaluronan Induced in vitro by Ascorbic Acid and Cu(II Ions

    Directory of Open Access Journals (Sweden)

    Mária Baňasová

    2014-10-01

    Full Text Available The bucillamine effect on free-radical-mediated degradation of high-molar-mass hyaluronan (HA has been elucidated. As HA fragmentation is expected to decrease its dynamic viscosity, rotational viscometry was applied to follow the oxidative HA degradation. Non-isothermal chemiluminometry, thermogravimetry, differential scanning calorimetry, and size-exclusion chromatography (SEC were applied to characterize resulting HA fragments. Although bucillamine completely inhibited the HA viscosity decrease caused by oxidative system, indicating HA protection from degradation, SEC analysis suggested that some other mechanisms leading to the bucillamine transformations without the decay of the viscosity may come into a play as well. Nonetheless, the link between the reduction of chemiluminescence intensity and disappearance of the differential scanning calorimetry exotherm at 270 °C for fragmented HAs indicates a particular role of the bucillamine in preventing the decrease of HA viscosity.

  10. DDB1 and CUL4 associated factor 11 (DCAF11) mediates degradation of Stem-loop binding protein at the end of S phase.

    Science.gov (United States)

    Djakbarova, Umidahan; Marzluff, William F; Köseoğlu, M Murat

    2016-08-01

    In eukaryotes, bulk histone expression occurs in the S phase of the cell cycle. This highly conserved system is crucial for genomic stability and proper gene expression. In metazoans, Stem-loop binding protein (SLBP), which binds to 3' ends of canonical histone mRNAs, is a key factor in histone biosynthesis. SLBP is mainly expressed in S phase and this is a major mechanism to limit bulk histone production to the S phase. At the end of S phase, SLBP is rapidly degraded by proteasome, depending on two phosphorylations on Thr 60 and Thr 61. Previously, we showed that SLBP fragment (aa 51-108) fused to GST, is sufficient to mimic the late S phase (S/G2) degradation of SLBP. Here, using this fusion protein as bait, we performed pull-down experiments and found that DCAF11, which is a substrate receptor of CRL4 complexes, binds to the phosphorylated SLBP fragment. We further confirmed the interaction of full-length SLBP with DCAF11 and Cul4A by co-immunoprecipitation experiments. We also showed that DCAF11 cannot bind to the Thr61/Ala mutant SLBP, which is not degraded at the end of S phase. Using ectopic expression and siRNA experiments, we demonstrated that SLBP expression is inversely correlated with DCAF11 levels, consistent with the model that DCAF11 mediates SLBP degradation. Finally, we found that ectopic expression of the S/G2 stable mutant SLBP (Thr61/Ala) is significantly more toxic to the cells, in comparison to wild type SLBP. Overall, we concluded that CRL4-DCAF11 mediates the degradation of SLBP at the end of S phase and this degradation is essential for the viability of cells. PMID:27254819

  11. c-FLIP antisense oligonucleotide-loaded nanoparticles inhibit growth of human orbital rhabdomyosarcoma xenograft in nude mice%c-FLIP反义寡核苷酸纳米粒抑制人眼眶横纹肌肉瘤裸鼠移植瘤的生长

    Institute of Scientific and Technical Information of China (English)

    梁莉; 魏锐利

    2013-01-01

    Objective To investigate the effect of cellular Fas-associated death domain-like interleukin-1β-converting enzyme-inhibitory protein (c-FLIP) antisense oligonucleotide (ASODN)-loaded nanoparticles (NP) on the human orbital rhabdomyosarcoma xenograft in nude mice,so as to assess the feasibility of nanoparticles as a gene vector.Methods The model of human orbital rhabdomyosarcoma xenograft was established in nude mice,and the tumors were injected with c-FLIP ASODN NP,c-FLIP ASODN or normal saline (NS).The tumor volume and histopathological changes of tumor were observed.Western blotting analysis and immunohistochemical analysis were used to examine the expression of c-FLIP in tumor tissues of each group.Apoptosis of tumor cells was detected using TUNEL method.Results The growth of human orbital rhabdomyosarcoma in nude mice was significantly inhibited in ASODN NP group compared with the other two groups.Western blotting analysis showed that c-FLIP protein expression in ASODN NP and ASODN groups was significantly decreased compared with NS group (P<0.05).Immunohistochemical study showed that c-FLIP expression was found in the endochylema,and the c-FLIP positive cells in ASODN NP group was significantly less than those in the other two groups (P<0.05).Tumor cell apoptosis was observed in both ASODN NP and ASODN groups,with more found in the former,and only a few apoptotic cells were found in the NS group.Conclusion c-FLIP ASODN NP can effectively inhibit the growth of human orbital rhabdomyosarcoma xenograft in nude mice,indicating that nanoparticles may serve as a safe and effective vector for ASODN.%目的 探讨c-FLIP反义寡核苷酸(c-FLIP ASODN)纳米粒(NP)对裸鼠体内人眼眶横纹肌肉瘤移植瘤生长的影响,评估纳米粒作为基因载体的可行性.方法 皮下种植法建立裸鼠人眼眶横纹肌肉瘤动物模型,瘤体内分别注射c-FLIP反义寡核苷酸纳米粒(ASODN NP组)、未包裹的c-FLIP反义寡核苷酸(ASODN组)及生

  12. Release of GTP Exchange Factor Mediated Down-Regulation of Abscisic Acid Signal Transduction through ABA-Induced Rapid Degradation of RopGEFs

    Science.gov (United States)

    Waadt, Rainer; Schroeder, Julian I.

    2016-01-01

    The phytohormone abscisic acid (ABA) is critical to plant development and stress responses. Abiotic stress triggers an ABA signal transduction cascade, which is comprised of the core components PYL/RCAR ABA receptors, PP2C-type protein phosphatases, and protein kinases. Small GTPases of the ROP/RAC family act as negative regulators of ABA signal transduction. However, the mechanisms by which ABA controls the behavior of ROP/RACs have remained unclear. Here, we show that an Arabidopsis guanine nucleotide exchange factor protein RopGEF1 is rapidly sequestered to intracellular particles in response to ABA. GFP-RopGEF1 is sequestered via the endosome-prevacuolar compartment pathway and is degraded. RopGEF1 directly interacts with several clade A PP2C protein phosphatases, including ABI1. Interestingly, RopGEF1 undergoes constitutive degradation in pp2c quadruple abi1/abi2/hab1/pp2ca mutant plants, revealing that active PP2C protein phosphatases protect and stabilize RopGEF1 from ABA-mediated degradation. Interestingly, ABA-mediated degradation of RopGEF1 also plays an important role in ABA-mediated inhibition of lateral root growth. The presented findings point to a PP2C-RopGEF-ROP/RAC control loop model that is proposed to aid in shutting off ABA signal transduction, to counteract leaky ABA signal transduction caused by “monomeric” PYL/RCAR ABA receptors in the absence of stress, and facilitate signaling in response to ABA. PMID:27192441

  13. Effect of enhanced reactive nitrogen availability on plant-sediment mediated degradation of polycyclic aromatic hydrocarbons in contaminated mangrove sediment.

    Science.gov (United States)

    Jiang, Shan; Lu, Haoliang; Zhang, Qiong; Liu, JingChun; Yan, Chongling

    2016-02-15

    As land-ocean interaction zones, mangrove systems receive substantial polycyclic aromatic hydrocarbons (PAHs) from sewage and combustion of fossil fuel. In this study, we investigated the relationship between dissolved inorganic nitrogen (DIN) availability and degradation rate of phenanthrene, a typical PAH compound, in mangrove plant-sediment systems, using Avicennia marina as a model plant. After 50day incubation, phenanthrene removal ratios in sediments ranged from 53.8% to 97.2%. In non-rhizosphere sediment, increasing DIN accessibility increased microbial biomass and total microbial activity, while enhancements in population size of phenanthrene degradation bacteria (PDB) and phenanthrene degradation rates were insignificant. In contrast, the presence of excessive DIN in rhizosphere sediment resulted in a significantly large number of PDB, leading to a rapid dissipation rate of phenanthrene. The differences in degradation rates and abundances of degrader in sediment may be explained by the enhanced root activity due to the elevation in DIN accessibility. PMID:26749225

  14. Sulfamethoxazole and isoproturon degradation and detoxification by a laccase-mediator system: Influence of treatment conditions and mechanistic aspects

    OpenAIRE

    Margot, Jonas; Copin, Pierre-Jean; VON GUNTEN, Urs; Barry, David Andrew; Holliger, Christof

    2015-01-01

    The potential of laccase-mediator systems (LMS) for the removal and detoxification of two wastewater micropollutants, the antibiotic sulfamethoxazole (SMX) and the herbicide isoproturon (IPN), was assessed. The influence of various parameters on micropollutant oxidation rates, such as pH, mediator, enzyme and pollutant concentrations, was investigated with three mediators: 2,2'′-azino-bis(3-ethylbenzthiazoline-6-sulphonic acid) (ABTS), syringaldehyde (SA) and acetosyringone (AS). Both polluta...

  15. Translation termination factor eRF3 is targeted for caspase-mediated proteolytic cleavage and degradation during DNA damage-induced apoptosis.

    Science.gov (United States)

    Hashimoto, Yoshifumi; Hosoda, Nao; Datta, Pinaki; Alnemri, Emad S; Hoshino, Shin-ichi

    2012-12-01

    Polypeptide chain release factor eRF3 plays pivotal roles in translation termination and post-termination events including ribosome recycling and mRNA decay. It is not clear, however, if eRF3 is targeted for the regulation of gene expression. Here we show that DNA-damaging agents (UV and etoposide) induce the immediate cleavage and degradation of eRF3 in a caspase-dependent manner. The effect is selective since the binding partners of eRF3, eRF1 and PABP, and an unrelated control, GAPDH, were not affected. Point mutations of aspartate residues within overlapping DXXD motifs near the amino terminus of eRF3 prevented the appearance of the UV-induced cleavage product, identifying D32 as the major cleavage site. The cleavage and degradation occurred in a similar time-dependent manner to those of eIF4G, a previously established caspase-3 target involved in the inhibition of translation during apoptosis. siRNA-mediated knockdown of eRF3 led to inhibition of cellular protein synthesis, supporting the idea that the decrease in the amount of eRF3 caused by the caspase-mediated degradation contributes to the inhibition of translation during apoptosis. This is the first report showing that eRF3 could serve as a target in the regulation of gene expression. PMID:23054082

  16. Hsp90 regulates processing of NF-κB2 p100 involving protection of NF-κB-inducing kinase (NIK) from autophagy-mediated degradation

    Institute of Scientific and Technical Information of China (English)

    Guoliang Qing; Pengrong Yan; Zhaoxia Qu; Hudan Liu; Gutian Xiao

    2007-01-01

    NF-κB-inducing kinase (NIK) is required for NF-κB activation based on the processing of NF-κB2 p100. Here we report a novel mechanism of NIK regulation involving the chaperone 90 kDa heat shock protein (Hsp90) and autophagy.Functional inhibition of lisp90 by the anti-tumor agent geldanamycin (GA) efficiently disrupts its interaction with NIK,resulting in NIK degradation and subsequent blockage of p100 processing. Surprisingly, GA-induced NIK degradation is mediated by autophagy, but largely independent of the ubiquitin-proteasome system. Hsp90 seems to be specifically involved in the folding/stabilization of NIK protein, because GA inhibition does not affect NIK mRNA transcription and translation. Furthermore, Hsp90 is not required for NIK-mediated recruitment of the α subunit of IκB kinase to p100, a key step in induction of p100 processing. These findings define an alternative mechanism for Hsp90 client degradation and identify a novel function of autophagy in NF-κB regulation. These findings also suggest a new therapeutic strategy for diseases associated with p100 processing.

  17. Ubiquitin ligase RNF123 mediates degradation of heterochromatin protein 1α and β in lamin A/C knock-down cells.

    Directory of Open Access Journals (Sweden)

    Pankaj Chaturvedi

    Full Text Available BACKGROUND: The nuclear lamina is a key determinant of nuclear architecture, integrity and functionality in metazoan nuclei. Mutations in the human lamin A gene lead to highly debilitating genetic diseases termed as laminopathies. Expression of lamin A mutations or reduction in levels of endogenous A-type lamins leads to nuclear defects such as abnormal nuclear morphology and disorganization of heterochromatin. This is accompanied by increased proteasomal degradation of certain nuclear proteins such as emerin, nesprin-1α, retinoblastoma protein and heterochromatin protein 1 (HP1. However, the pathways of proteasomal degradation have not been well characterized. METHODOLOGY/PRINCIPAL FINDINGS: To investigate the mechanisms underlying the degradation of HP1 proteins upon lamin misexpression, we analyzed the effects of shRNA-mediated knock-down of lamins A and C in HeLa cells. Cells with reduced levels of expression of lamins A and C exhibited proteasomal degradation of HP1α and HP1β but not HP1γ. Since specific ubiquitin ligases are upregulated in lamin A/C knock-down cells, further studies were carried out with one of these ligases, RNF123, which has a putative HP1-binding motif. Ectopic expression of GFP-tagged RNF123 directly resulted in degradation of HP1α and HP1β. Mutational analysis showed that the canonical HP1-binding pentapeptide motif PXVXL in the N-terminus of RNF123 was required for binding to HP1 proteins and targeting them for degradation. The role of endogenous RNF123 in the degradation of HP1 isoforms was confirmed by RNF123 RNAi experiments. Furthermore, FRAP analysis suggested that HP1β was displaced from chromatin in laminopathic cells. CONCLUSIONS/SIGNIFICANCE: Our data support a role for RNF123 ubiquitin ligase in the degradation of HP1α and HP1β upon lamin A/C knock-down. Hence lamin misexpression can cause degradation of mislocalized proteins involved in key nuclear processes by induction of specific components of

  18. Adenovirus containing c-FLIPs gene induces antiapoptosis activation of lymphocyte in vitro%腺病毒介导c-FLIPs基因诱导淋巴细胞抗凋亡作用

    Institute of Scientific and Technical Information of China (English)

    冯子毅; 李宝金; 刘晓平

    2005-01-01

    目的探讨表达c-FLIPs重组腺病毒诱导淋巴细胞抗凋亡作用.方法采用RT-PCR方法,从人T淋巴细胞株的总RNA中克隆c-FLIPs基因;通过pAdeasy系统,构建表达c-FLIPs的重组腺病毒Ad.c-FLIPs;Hochest染色法及PI染色流式细胞仪检测anti-Apo-1诱导感染Ad.c-FLIPs后的H9细胞凋亡.结果采用RT-PCR方法从人T淋巴细胞株中扩增出c-FLIPs基因;构建重组腺病毒Ad.c-FLIPs;经Hoechst染色,荧光显微镜下观察细胞核的形态,结果发现,经anti-Apo-1诱导凋亡处理24 h后,未经Ad.c-FLIPs感染的H9细胞有大量的细胞核呈浓染致密的固缩形态或颗粒状荧光的凋亡细胞;Ad.c-FLIPs感染的H9细胞中细胞核呈浓染致密的固缩形态或颗粒状荧光的细胞数明显减少,大部分细胞染色质呈弥漫均匀低强度荧光;流式细胞仪分析经PI染色后的H9细胞,未经Ad.c-FLIPs预处理的H9细胞在anti-Apo-1作用24 h后,细胞的凋亡率分别为48.33%±7.41%;经Ad.c-FLIPs预处理1 d的H9细胞,其细胞凋亡率分别下降到3.60%±0.21%.结论重组腺病毒Ad.c-FLIPs可有效地诱导淋巴细胞的抗凋亡作用.

  19. Chaperone Hsp27 modulates AUF1 proteolysis and AU-rich element-mediated mRNA degradation.

    Science.gov (United States)

    Knapinska, Anna M; Gratacós, Frances M; Krause, Christopher D; Hernandez, Kristina; Jensen, Amber G; Bradley, Jacquelyn J; Wu, Xiangyue; Pestka, Sidney; Brewer, Gary

    2011-04-01

    AUF1 is an AU-rich element (ARE)-binding protein that recruits translation initiation factors, molecular chaperones, and mRNA degradation enzymes to the ARE for mRNA destruction. We recently found chaperone Hsp27 to be an AUF1-associated ARE-binding protein required for tumor necrosis factor alpha (TNF-α) mRNA degradation in monocytes. Hsp27 is a multifunctional protein that participates in ubiquitination of proteins for their degradation by proteasomes. A variety of extracellular stimuli promote Hsp27 phosphorylation on three serine residues--Ser(15), Ser(78), and Ser(82)-by a number of kinases, including the mitogen-activated protein (MAP) pathway kinases p38 and MK2. Activating either kinase stabilizes ARE mRNAs. Likewise, ectopic expression of phosphomimetic mutant forms of Hsp27 stabilizes reporter ARE mRNAs. Here, we continued to examine the contributions of Hsp27 to mRNA degradation. As AUF1 is ubiquitinated and degraded by proteasomes, we addressed the hypothesis that Hsp27 phosphorylation controls AUF1 levels to modulate ARE mRNA degradation. Indeed, selected phosphomimetic mutants of Hsp27 promote proteolysis of AUF1 in a proteasome-dependent fashion and render ARE mRNAs more stable. Our results suggest that the p38 MAP kinase (MAPK)-MK2-Hsp27 signaling axis may target AUF1 destruction by proteasomes, thereby promoting ARE mRNA stabilization. PMID:21245386

  20. [Plasmid pJP4 mediated gene horizontal transfer in a biofilm system and its effect on 2, 4-D degradation].

    Science.gov (United States)

    Quan, Xiang-Chun; Tang, Hua; Hu, Li-Juan; Wang, Ran; Zhang, Ning

    2009-09-15

    With plasmid pJP4 (which contains functional gene cluster (tfd) encoding 2,4-D degradation) carrying genetic microorganism Pseudomonas putida SM1443:: gfp2x (pJP4:: dsRed) as the donor strain, events of plasmid mediated gene horizontal transfer and its effect on 2,4-D degradation was investigated in a biofilm system operated under fed-batch mode. The surviving status of the functional gene element in the gene-augmented system and effects of gene-augmentation on microbial community structure were also investigated. Results showed that introduction of pJP4 carrying strain to the biofilm system with 2, 4-D (initial concentration at 170 mg/L +/- 10 mg/L) as the sole carbon source could enhance the degradation of 2, 4-D. Enhancement was slight during the initial stage of operation, but it increased with increasing of fed batch runs. Difference in 2, 4-D average degradation rate between gene-augmented system and the control system achieved up to 13.3 mg/(L x h) at most. Through detecting functional gene tfdB and reporter gene gfp, pJP4 mediated gene horizontal transfer to the bacteria on biofilm was further approved. Effects of gene augmentation on microbial community structure was analyzed by PCR-DGGE analysis, and results showed that relatively higher stability of microbial community was maintained for the gene-augmented biofilm system compared to the control system when facing 2,4-D shock loadings. PMID:19927832

  1. Effect of size and conformation of the ligand on asialoglycoprotein receptor-mediated ligand internalization and degradation in rat hepatocytes

    International Nuclear Information System (INIS)

    The rates of internalization and degradation of 125-I-labeled desialylated cyanogen bromide fragment I of orosomucoid (AS-CNBr-I) and its reduced and carboxymethylated derivative (AS-RC-CNBr-I) were compared with those of 125I-labeled asialoorosomucoid (ASOR) in rat hepatocytes. At 30 nM the rates of internalization and degradation of 125I-AS-CNBr-I were greater than those of 125I-ASOR. 125I-AS-RC-CNBr-I also had a lower rate of internalization and degradation. In contrast to 125I-ASOR, when degradation was inhibited by 5 μM colchicine there was a significant intracellular accumulation of the smaller ligands. At 40C the hepatocytes were found to bind the fragmented ligands more than 125I-ASOR. Incubation of the cells with bound ligand at 370 indicated that diacytosis of 125I-ASOR was greater than the smaller ligands. Colchincine markedly enhanced diacytosis of 125I-ASOR. On the other hand, there were marked accumulation of the smaller ligands by colchicine. These results suggest that the rates of internalization, degradation and diacytosis of the ligand are affected by the size and conformation of the ligand through different rates of receptor binding and intracellular transport

  2. Role of nutrients and illuminance in predicting the fate of fungal mediated petroleum hydrocarbon degradation and biomass production.

    Science.gov (United States)

    Ali Khan, Aqib Hassan; Tanveer, Sundus; Anees, Mariam; Muhammad, Yousaf Shad; Iqbal, Mazhar; Yousaf, Sohail

    2016-07-01

    Biodegradation and biomass production are affected by numerous environmental factors including pH, oxygen availability and presence of pollutants. The present study, for the first time, elucidated the effects of nutrients and light on mycodegradation of petroleum hydrocarbons in diesel oil. Seven fungal strains (Aspergillus terreus FA3, Aspergillus niger FA5, Aspergillus terreus FA6, Penicillium chrysogenum FP4, Aspergillus terreus FP6, Aspergillus flavus FP10, and Candida sp. FG1) were used for hydrocarbon degradation under static conditions, in four combinations of nutrient media and illuminance for 45 days. Highest degradation was achieved by Aspergillus terreus FA6 and Candida sp. FG1 under both conditions of light and dark, with nutrient deprived HAF (Hydrocarbon adopted fungi) broth. Under HAF/Dark diesel oil degradation by FA6 and FG1 was 87.3% and 84.3% respectively, while under HAF/Light both FA6 and FG1 performed 84.3% biodegradation. The highest biomass was produced by Aspergillus flavus FP10 in PDB (Potato dextrose broth)/Dark (109.3 mg). Fungal degradation of petroleum hydrocarbons was negatively affected by the presence of other simpler-to-degrade carbon sources in the medium. The biomass production was enhanced by improved nutrient availability and diminished by illuminance. PMID:27039364

  3. c-FLIP和NF-κB p65在乳腺癌组织中的表达及临床意义%Expression of c-FLIP and NF-κB p65 in breast cancer and their clinical significance

    Institute of Scientific and Technical Information of China (English)

    潘峥; 陈军; 覃冠德; 覃思繁

    2012-01-01

    目的:探讨凋亡相关蛋白c-FLIP和NF-κB p65在人乳腺癌的表达及相关性,分析其与乳腺癌转移复发的关系.方法:应用免疫组织化学法检测80例乳腺癌组织和相应的癌旁组织中c-FLIP和NF-κBp65的表达情况.结果:80例乳腺癌组织中c-FLIP及NF-κB p65表达的阳性率显著高于相应的癌旁组织(P<0.05),c-FLIP的表达与TNM分期、组织学分级、腋窝淋巴结转移、术后复发及C-erbB-2表达密切相关(P<O.05);NF-κB p65的表达组织学分级、肿瘤大小及腋窝淋巴结转移密切相关(P<0.05).c-FLIP和NF-κB p65的表达有显著正相关性(γ=0.271,P=O.015).结论:c-FLIP和NF-κB p65的高表达可能在乳腺癌的发生及进展中起着重要作用.%Objective:To investigate the expression of c - FLIP and NF - KB p65 in breast career and their correlation with metastasis and recurrence. Methods: Immunohistochemistry was employed to determine the expression of c - FLIP and NF - KB p65 in 80 breast carcinomas and paired adjacent breast tis8ues. Results; c - FLIP and NF -ΚB p65 were overexpressed in breast cancers compared with paired adjacent breast tissues. The expression of c - FLIP was significantly correlated with TNM stages, histological grade, axillary lymph node metastasis, the recurrence of tumor and the express of C - erbB - 2. The expression of NF -κB p65 was significantly correlated with histological grade, tumor size and axillary lymph node metastasis . There was a significantly positive relationship of c - FLIP with NF - κB p65. Conclusion: The overexpression of c - FLIP and NF - KB p65 might enhance the tumour cell proliferation and malignanee and play an important role in progress of human breast cancer.

  4. Degradation of cytokinins by maize cytokinin dehydrogenase is mediated by free radicals generated by enzymatic oxidation of natural benzoxazinones

    Czech Academy of Sciences Publication Activity Database

    Frébortová, Jitka; Novák, Ondřej; Frébort, Ivo; Jorda, Radek

    2010-01-01

    Roč. 61, č. 3 (2010), s. 467-481. ISSN 0960-7412 R&D Projects: GA ČR GA522/05/0448; GA ČR GA301/08/1649 Institutional research plan: CEZ:AV0Z50380511 Keywords : Degradation * cytokinins * maize Subject RIV: EF - Botanics Impact factor: 6.948, year: 2010

  5. The presence of C/EBPα and its degradation are both required for TRIB2-mediated leukaemia

    DEFF Research Database (Denmark)

    O'Connor, C; Lohan, F; Campos, J;

    2016-01-01

    C/EBPα (p42 and p30 isoforms) is commonly dysregulated in cancer via the action of oncogenes, and specifically in acute myeloid leukaemia (AML) by mutation. Elevated TRIB2 leads to the degradation of C/EBPα p42, leaving p30 intact in AML. Whether this relationship is a cooperative event in AML...

  6. Efficient degradation of carbamazepine by easily recyclable microscaled CuFeO2 mediated heterogeneous activation of peroxymonosulfate.

    Science.gov (United States)

    Ding, Yaobin; Tang, Hebin; Zhang, Shenghua; Wang, Songbo; Tang, Heqing

    2016-11-01

    Microscaled CuFeO2 particles (micro-CuFeO2) were rapidly prepared via a microwave-assisted hydrothermal method and characterized by scanning electron microscopy, X-ray powder diffraction and X-ray photoelectron spectroscopy. It was found that the micro-CuFeO2 was of pure phase and a rhombohedral structure with size in the range of 2.8±0.6μm. The micro-CuFeO2 efficiently catalyzed the activation of peroxymonosulfate (PMS) to generate sulfate radicals (SO4-), causing the fast degradation of carbamazepine (CBZ). The catalytic activity of micro-CuFeO2 was observed to be 6.9 and 25.3 times that of micro-Cu2O and micro-Fe2O3, respectively. The enhanced activity of micro-CuFeO2 for the activation of PMS was confirmed to be attributed to synergistic effect of surface bonded Cu(I) and Fe(III). Sulfate radical was the primary radical species responsible for the CBZ degradation. As a microscaled catalyst, micro-CuFeO2 can be easily recovered by gravity settlement and exhibited improved catalytic stability compared with micro-Cu2O during five successive degradation cycles. Oxidative degradation of CBZ by the couple of PMS/CuFeO2 was effective in the studied actual aqueous environmental systems. PMID:27329789

  7. Lymphoid enhancer factor-1 blocks adenomatous polyposis coli-mediated nuclear export and degradation of beta-catenin. Regulation by histone deacetylase 1.

    Science.gov (United States)

    Henderson, Beric R; Galea, Melanie; Schuechner, Stefan; Leung, Louie

    2002-07-01

    The oncogenic protein beta-catenin is overexpressed in many cancers, frequently accumulating in nuclei where it forms active complexes with lymphoid enhancer factor-1 (LEF-1)/T-cell transcription factors, inducing genes such as c-myc and cyclin D1. In normal cells, nuclear beta-catenin levels are controlled by the adenomatous polyposis coli (APC) protein through nuclear export and cytoplasmic degradation. Transient expression of LEF-1 is known to increase nuclear beta-catenin levels by an unknown mechanism. Here, we show that APC and LEF-1 compete for nuclear beta-catenin with opposing consequences. APC can export nuclear beta-catenin to the cytoplasm for degradation. In contrast, LEF-1 anchors beta-catenin in the nucleus by blocking APC-mediated nuclear export. LEF-1 also prevented the APC/CRM1-independent nuclear export of beta-catenin as revealed by in vitro assays. Importantly, LEF-1-bound beta-catenin was protected from degradation by APC and axin in SW480 colon cancer cells. The ability of LEF-1 to trap beta-catenin in the nucleus was down-regulated by histone deacetylase 1, and this correlated with a decrease in LEF1 transcription activity. Our findings identify LEF-1 as key regulator of beta-catenin nuclear localization and stability and suggest that overexpression of LEF-1 in colon cancer and melanoma cells may contribute to the accumulation of oncogenic beta-catenin in the nucleus. PMID:11986304

  8. 凋亡抑制蛋白c-FLIP(L)对肺癌细胞增殖迁移的影响%The effect of cellular FLICE-like inhibitory protein(c-FLIP(L)) on cell migration in lung cancer cell

    Institute of Scientific and Technical Information of China (English)

    刘万; 郑倩倩; 华子春; 张晶

    2015-01-01

    Objective:Cellular FLICE-like inhibitory protein ( c-FLIP ( L ) ) is an important target for cancer therapy.In this study, we established stable cell line in A549 overexpressing c-FLIP ( L) and to examine the potential role of c-FLIP ( L ) in migration of lung cancer cells.Methods: A549 cells was transfected with recombinant plasmid pcDNA3.1-FLIP and then selected with G418.Expressions of c-FLIP(L) in stable cells were detected by QPCR and Western Blot.The effect of c-FLIP ( L) on cell migration was determined using Would healing and Transwell assays, respectively.Results:c-FLIP( L) was successfully highly expressed in A549 stable cells, and increased expression of c-FLIP( L) significantly promoted cell migration testified by Wound healing and Transwell assay.Conclusion: c-FLIP ( L) is upregualted in A549 cells relative to the migration ability.This finding is helpful for exploring the molecular mechanism of metastasis in lung cancer cells.%目的:近来凋亡抑制蛋白c-FLIP( L)作为新的抗肿瘤治疗靶点受到关注,为了探讨c-FLIP( L)在肺癌细胞迁移中的作用,我们建立了c-FLIP( L)高表达稳定细胞株,以比较c-FLIP( L)在肺癌细胞株中表达水平与其细胞迁移能力的关系。方法:采用非小细胞肺癌A549细胞株进行转染c-FLIP( L)真核表达质粒,通过G418筛选出多株c-FLIP( L)高表达单克隆,以此为平台研究c-FLIP( L)在肿瘤细胞迁移过程中的作用。通过实时荧光定量QPCR及Western Blot检测稳定株中c-FLIP( L)表达水平;划痕实验及Transwell法检测c-FLIP( L)高表达对肺癌细胞迁移的影响,并通过荧光骨架蛋白染色观察细胞形态的改变。结果:QPCR和Western Blot显示A549稳定细胞株中c-FLIP( L)均为高表达;Wound healing和Transwell实验表明c-FLIP ( L)高表达肺癌细胞迁移能力明显上升,并初步探索了c-FLIP( L)表达对细胞骨架

  9. 脓毒症大鼠肺组织c-FLIP的变化及乌司他丁对c-FLIP的影响%The changes of c-FLIP in the lung of rats with sepsis and the influence of Ulinastatin

    Institute of Scientific and Technical Information of China (English)

    沈蕾; 孙正达; 陈琦; 曹同瓦; 祝禾辰

    2010-01-01

    目的 观察脓毒症大鼠的肺组织中c-FLIP的变化情况,并探讨乌司他丁对c-FLIP水平的影响.方法 将30只雄性Sprague-Dawley大鼠随机(随机数字法)分为假手术组(Sham组)、脓毒症模型组(CLP组)及乌司他丁治疗组(UTI组),每组10只.Sham组不结扎穿刺盲肠,余同CLP组;CLP组采用肓肠结扎并穿刺法造模;UTI组造模后立即经阴茎静脉注射乌司他丁注射液(50000 U/kg).12 h后处死大鼠并采取肺组织,光镜下观察形态学变化;Western-Blot法检测c-FLIP蛋白表达,RT-PCR法检测c-FLIP基因表达.应用SPSS 11.5进行统计学分析,多组比较采用方差分析,两两比较采用LSD-t检验.结果 脓毒症组光镜下肺泡腔内中性粒细胞和大量红细胞渗出,c-FLIP蛋白和基因表达较假手术组显著降低(P<0.05);用乌司他丁治疗后,光镜下病理改变减轻,c-FLIP蛋白和基因表达较脓毒症组显著升高(P<0.05).结论 脓毒症中c-FLIP在肺组织中的表达下降,提示肺组织的细胞凋亡增加.乌司他丁能上调脓毒症大鼠肺组织中c-FLIP的表达.%Objective To explore the changes of e-FLIP in the lung of rats with sepsis,and to investigate the effect of Ulinastatin on the level of c-FLIP.Method Thirty male Spragne-Dawley rats were randomly(random number)divided into 3 groups:sham operated group(Sham),sepsis group(CLP)and Ulinastatin treated group (UTI),n=10,respectively.In Sham group,only laparotomy was performed.In CLP and UTI groups,cecal ligation and puncture was performed to induce sepsis.Ulinastatin(50 000 U/kg)was administered intravenously via penile vein in UTI group after operation.The same volume of normal saune instead of Ulinastatin was administered intravenously in Sham and CLP groups.The lungs of rats were harvested 12 hours after operation for determination of c-FLIP mRNA expressions assayed by using RT-PCR and cFLIP protein measured by Western blot.Statistical analysis was performed with SPSS version 11.5 software

  10. The nucleolar SUMO-specific protease SMT3IP1/SENP3 attenuates Mdm2-mediated p53 ubiquitination and degradation

    International Nuclear Information System (INIS)

    Research highlights: → SMT3IP1 interacts with p53 and Mdm2, and desumoylates both proteins. → SMT3IP1 competes with p53 for binding to the central acidic domain of Mdm2. → SMT3IP1 binding to Mdm2 inhibits Mdm2-mediated p53 ubiquitination and degradation. → We postulate that SMT3IP1 acts as a new regulator of the p53-Mdm2 pathway. -- Abstract: SUMO (small ubiquitin-like modifier) modification plays multiple roles in several cellular processes. Sumoylation is reversibly regulated by SUMO-specific proteases. SUMO-specific proteases have recently been implicated in cell proliferation and early embryogenesis, but the underlying mechanisms remain unknown. Here, we show that a nucleolar SUMO-specific protease, SMT3IP1/SENP3, controls the p53-Mdm2 pathway. We found that SMT3IP1 interacts with p53 and Mdm2, and desumoylates both proteins. Overexpression of SMT3IP1 in cells resulted in the accumulation of Mdm2 in the nucleolus and increased stability of the p53 protein. In addition, SMT3IP1 bound to the acidic domain of Mdm2, which also mediates the p53 interaction, and competed with p53 for binding. Increasing expression of SMT3IP1 suppressed Mdm2-mediated p53 ubiquitination and subsequent proteasomal degradation. Interestingly, the desumoylation activity of SMT3IP1 was not necessary for p53 stabilization. These results suggest that SMT3IP1 is a new regulator of the p53-Mdm2 pathway.

  11. Ndfip-mediated degradation of Jak1 tunes cytokine signalling to limit expansion of CD4+ effector T cells

    Science.gov (United States)

    O'Leary, Claire E.; Riling, Christopher R.; Spruce, Lynn A.; Ding, Hua; Kumar, Suresh; Deng, Guoping; Liu, Yuhong; Seeholzer, Steven H.; Oliver, Paula M.

    2016-01-01

    Nedd4 family E3 ubiquitin ligases have been shown to restrict T-cell function and impact T-cell differentiation. We show here that Ndfip1 and Ndfip2, activators of Nedd4 family ligases, together limit accumulation and function of effector CD4+ T cells. Using a three-part proteomics approach in primary T cells, we identify stabilization of Jak1 in Ndfip1/2-deficient T cells stimulated through the TCR. Jak1 degradation is aborted in activated T cells that lack Ndfips. In wild-type cells, Jak1 degradation lessens CD4+ cell sensitivity to cytokines during TCR stimulation, while in Ndfip-deficient cells cytokine responsiveness persists, promoting increased expansion and survival of pathogenic effector T cells. Thus, Ndfip1/Ndfip2 regulate the cross talk between the T-cell receptor and cytokine signalling pathways to limit inappropriate T-cell responses. PMID:27088444

  12. Ling Zhi-8 reduces lung cancer mobility and metastasis through disruption of focal adhesion and induction of MDM2-mediated Slug degradation.

    Science.gov (United States)

    Lin, Tung-Yi; Hsu, Hsien-Yeh

    2016-06-01

    We recently reported that recombinant Ling Zhi-8 (rLZ-8), a medicinal mushroom Ganoderma lucidum recombinant protein, effectively prevents lung cancer cells proliferation in vivo mice model. In our current study, we demonstrated that rLZ-8 suppressed tumor metastasis and increased the survival rate in Lewis lung carcinoma cell-bearing mice. The epithelial to mesenchymal transition (EMT) process is regarded as the critical event in tumor metastasis. Herein, we showed that rLZ-8 effectively induced changes in EMT by interfering with cell adhesion and focal adhesion kinase (FAK) functions in lung cancer cells. Slug, a transcription factor, represses E-cadherin transcription and is regarded as a critical event in EMT and tumor metastasis. Functional studies revealed that downregulation of Slug as a result of rLZ-8-induced FAK inactivation enhanced E-cadherin expression and repressed cancer cell mobility. Moreover, we found that rLZ-8 enhanced the ubiquitination proteasome pathway (UPP)-mediated degradation of Slug in CL1-5 cells. Mechanistically, we demonstrated that rLZ-8 promoted the interaction between MDM2 and Slug, resulting in Slug degradation; however, MDM2-shRNA abolished rLZ-8-enhanced Slug degradation. This study is the first to determine anti-metastatic activity of rLZ-8 and its potential mechanism, with how the regulation of EMT and cell mobility is via the negative modulation of FAK, and thereby leading to the ubiquitination and degradation of Slug. Our findings suggest that the targets of FAK play a key role in metastasis. Moreover, rLZ-8 may be useful as a chemotherapeutic agent for treating lung cancer. PMID:26992741

  13. Differential control of ATGL-mediated lipid droplet degradation by CGI-58 and G0S2

    OpenAIRE

    Lu, Xin; Yang, Xingyuan; Liu, Jun

    2010-01-01

    Lipid droplets (LDs) are intracellular storage sites for triacylglyerols (TAGs) and steryl esters, and play essential roles in energy metabolism and membrane biosynthesis. Adipose triglyceride lipase (ATGL) is the key enzyme for TAG hydrolysis (lipolysis) in adipocytes and LD degradation in nonadipocyte cells. Lipase activity of ATGL in vivo largely depends on its C-terminal sequence as well as coactivation by CGI-58. Here we demonstrate that the C-terminal hydrophobic domain in ATGL is requi...

  14. Degradation of cytokinins by maize cytokinin dehydrogenase is mediated by free radicals generated by enzymatic oxidation of natural benzoxazinones

    OpenAIRE

    Frébortová, J. (Jitka); Novák, O.; Frébort, I. (Ivo); Jorda, R. (Radek)

    2010-01-01

    Hydroxamic acid 2,4-dihydroxy-7-methoxy-1,4-benzoxazin-one (DIMBOA) was isolated from maize phloem sap as a compound enhancing the degradation of isopentenyl adenine by maize cytokinin dehydrogenase (CKX), after oxidative conversion by either laccase or peroxidase. Laccase and peroxidase catalyze oxidative cleavage of DIMBOA to 4-nitrosoresorcinol-1-monomethyl ether (coniferron), which serves as a weak electron acceptor of CKX. The oxidation of DIMBOA and coniferron generates transitional fre...

  15. Matrix metalloproteinase-9-mediated type III collagen degradation as a novel serological biochemical marker for liver fibrogenesis

    DEFF Research Database (Denmark)

    Veidal, Sanne S; Vassiliadis, Efstathios; Barascuk, Natasha;

    2010-01-01

    During fibrogenesis in the liver, in which excessive remodelling of the extracellular matrix (ECM) occurs, both the quantity of type III collagen (CO3) and levels of matrix metalloproteinases (MMPs), including MMP-9, increase significantly. MMPs play major roles in ECM remodelling, via their...... activity in the proteolytic degradation of extracellular macromolecules such as collagens, resulting in the generation of specific cleavage fragments. These neo-epitopes may be used as markers of fibrosis....

  16. Modulation of defect-mediated energy transfer from ZnO nanoparticles for the photocatalytic degradation of bilirubin

    Directory of Open Access Journals (Sweden)

    Tanujjal Bora

    2013-11-01

    Full Text Available In recent years, nanotechnology has gained significant interest for applications in the medical field. In this regard, a utilization of the ZnO nanoparticles for the efficient degradation of bilirubin (BR through photocatalysis was explored. BR is a water insoluble byproduct of the heme catabolism that can cause jaundice when its excretion is impaired. The photocatalytic degradation of BR activated by ZnO nanoparticles through a non-radiative energy transfer pathway can be influenced by the surface defect-states (mainly the oxygen vacancies of the catalyst nanoparticles. These were modulated by applying a simple annealing in an oxygen-rich atmosphere. The mechanism of the energy transfer process between the ZnO nanoparticles and the BR molecules adsorbed at the surface was studied by using steady-state and picosecond-resolved fluorescence spectroscopy. A correlation of photocatalytic degradation and time-correlated single photon counting studies revealed that the defect-engineered ZnO nanoparticles that were obtained through post-annealing treatments led to an efficient decomposition of BR molecules that was enabled by Förster resonance energy transfer.

  17. Poly-ADP-ribosylation-mediated degradation of ARTD1 by the NLRP3 inflammasome is a prerequisite for osteoclast maturation

    Science.gov (United States)

    Wang, C; Qu, C; Alippe, Y; Bonar, S L; Civitelli, R; Abu-Amer, Y; Hottiger, M O; Mbalaviele, G

    2016-01-01

    Evidence implicates ARTD1 in cell differentiation, but its role in skeletal metabolism remains unknown. Osteoclasts (OC), the bone-resorbing cells, differentiate from macrophages under the influence of macrophage colony-stimulating factor (M-CSF) and receptor-activator of NF-κB ligand (RANKL). We found that M-CSF induced ADP-ribosyltransferase diphtheria toxin-like 1 (ARTD1) auto-ADP-ribosylation in macrophages, a modification that marked ARTD1 for cleavage, and subsequently, for degradation upon RANKL exposure. We established that ARTD1 proteolysis was NLRP3 inflammasome-dependent, and occurred via the proteasome pathway. Since ARTD1 is cleaved at aspartate214, we studied the impact of ARTD1 rendered uncleavable by D214N substitution (ARTD1D214N) on skeletal homeostasis. ARTD1D214N, unlike wild-type ARTD1, was resistant to cleavage and degradation during osteoclastogenesis. As a result, ARTD1D214N altered histone modification and promoted the abundance of the repressors of osteoclastogenesis by interfering with the expression of B lymphocyte-induced maturation protein 1 (Blimp1), the master regulator of anti-osteoclastogenic transcription factors. Importantly, ARTD1D214N-expressing mice exhibited higher bone mass compared with controls, owing to decreased osteoclastogenesis while bone formation was unaffected. Thus, unless it is degraded, ARTD1 represses OC development through transcriptional regulation. PMID:27010854

  18. Expression of PEDF and C-FLIP in Tissues of Colorectal Carcinoma and Its Clinical Pathological Significance%PEDF 和C-FLIP在大肠癌组织中的表达及其临床意义

    Institute of Scientific and Technical Information of China (English)

    彭志洋; 曾飞

    2009-01-01

    目的 探讨大肠癌组织中pigment epithelium-derived factor(PEDF)和celluar FLICE-inhibitory protein(C-FLIP)的表达及其与大肠癌临床病理因素之间的关系以及其临床意义.方法 应用免疫组化SP法检测45例大肠癌及15例癌旁组织内PEDF和C-FLIP的表达情况.结果 45例大肠癌中的PEDF和C-FLIP的表达率分别是:42%(19/45)和71%(32/45),15例癌旁正常组织中PEDF和C-FLIP的表达率分别为100%(15/15)和6.7%(1/15).PEDF的表达与肿瘤的浸润深度、分化程度、淋巴结转移、远处转移及临床分期呈负相关.C-FLIP的表达与肿瘤的浸润深度,淋巴结转移,临床分期呈正相关.PEDF与C-FLIP表达呈负相关(P<0.05).结论 PEDF可抑制大肠癌的进展,C-FLIP在大肠癌的发生发展中起促进作用.联合检测PEDF和C-FLIP的表达水平,有助于判断病情,对患者的治疗及预后评估具有一定的临床价值.

  19. Competition between Decapping Complex Formation and Ubiquitin-Mediated Proteasomal Degradation Controls Human Dcp2 Decapping Activity

    OpenAIRE

    Erickson, Stacy L.; Corpuz, Elizabeth O.; Maloy, Jeffrey P.; Fillman, Christy; Webb, Kristofer; Bennett, Eric J.; Lykke-Andersen, Jens

    2015-01-01

    mRNA decapping is a central step in eukaryotic mRNA decay that simultaneously shuts down translation initiation and activates mRNA degradation. A major complex responsible for decapping consists of the decapping enzyme Dcp2 in association with decapping enhancers. An important question is how the activity and accumulation of Dcp2 are regulated at the cellular level to ensure the specificity and fidelity of the Dcp2 decapping complex. Here, we show that human Dcp2 levels and activity are contr...

  20. Neurofibromatosis type 2 tumor suppressor protein, NF2, induces proteasome-mediated degradation of JC virus T-antigen in human glioblastoma.

    Directory of Open Access Journals (Sweden)

    Sarah Beltrami

    Full Text Available Neurofibromatosis type 2 protein (NF2 has been shown to act as tumor suppressor primarily through its functions as a cytoskeletal scaffold. However, NF2 can also be found in the nucleus, where its role is less clear. Previously, our group has identified JC virus (JCV tumor antigen (T-antigen as a nuclear binding partner for NF2 in tumors derived from JCV T-antigen transgenic mice. The association of NF2 with T-antigen in neuronal origin tumors suggests a potential role for NF2 in regulating the expression of the JCV T-antigen. Here, we report that NF2 suppresses T-antigen protein expression in U-87 MG human glioblastoma cells, which subsequently reduces T-antigen-mediated regulation of the JCV promoter. When T-antigen mRNA was quantified, it was determined that increasing expression of NF2 correlated with an accumulation of T-antigen mRNA; however, a decrease in T-antigen at the protein level was observed. NF2 was found to promote degradation of ubiquitin bound T-antigen protein via a proteasome dependent pathway concomitant with the accumulation of the JCV early mRNA encoding T-antigen. The interaction between T-antigen and NF2 maps to the FERM domain of NF2, which has been shown previously to be responsible for its tumor suppressor activity. Co-immunoprecipitation assays revealed a ternary complex among NF2, T-antigen, and the tumor suppressor protein, p53 within a glioblastoma cell line. Further, these proteins were detected in various degrees in patient tumor tissue, suggesting that these associations may occur in vivo. Collectively, these results demonstrate that NF2 negatively regulates JCV T-antigen expression by proteasome-mediated degradation, and suggest a novel role for NF2 as a suppressor of JCV T-antigen-induced cell cycle regulation.

  1. Expression and clinical significance of c-FLIP and NF-κB p65 in gastric carcinoma tissue%胃癌组织中c-FLIP、NF-κB p65的表达变化及意义

    Institute of Scientific and Technical Information of China (English)

    陈军; 覃思繁; 林思彤; 韦常宏

    2013-01-01

    目的 探讨细胞型Fas相关的死亡区域蛋白样白介素-1转换酶抑制蛋白(c-FLIP)、细胞核因子κB(NF-κB)在胃癌发生、发展中的作用.方法 选择胃癌组织标本80份(胃癌组)和癌旁组织80份(癌旁组),采用免疫组化法检测两组的c-FLIP、NF-κB p65,分析其与胃癌临床病理特征的关系.结果 胃癌组c-FLIP、NF-κB p65阳性率明显高于癌旁组(P均<0.05);c-FLIP的表达与胃癌临床分期、分化程度、淋巴结转移、术后复发相关(P均<0.05),NF-κB p65的表达与浸润深度、分化程度、淋巴结转移、术后复发相关(P均<0.05);c-FLIP和NF-κBp65在胃癌组织中的表达呈正相关(r =0.303,P=0.006).结论 c-FLIP、NF-κB p65的高表达可能在胃癌的发生、发展中起重要作用.%Objective To investigate the roles of cellular Fas-associated death domain-like interleulin-1 0 converting engyme inhibitory protein (c-FLIP) and nuclear factor kappa B(NF-κB) p65 in the incidence and development of gastric carcinoma. Methods Collected 80 cases of gastric carcinoma tissue ( gastric carcinoma group) and 80 cases of paired adjacent gastric tissue( adjacent gastric carcinoma group) , immunohistochemisty was employed to determine the expression of c-FLIP and NF-κB p65 in the two groups. The relationship between c-FLIP and NF-κB p65, and their correlation with clinical parameters was analyzed. Results The positive rate of c-FLIP and NF- κB p65 was significantly higher in gastric carcinoma group than in adjacent gastric carcinoma group ( all P < 0.05). The expression of c-FLJP was significantly correlated with the clinical stage, the degree of tumor differentiation, the lymph node metastasis and the recurrence of tumor (all P < 0.05 ). The expression of NF-kB p65 was significantly correlated with the invaded depth, the degree of tumor differentiation , the lymph node metastasis and the recurrence of tumor (all P < 0.05 ) . There was a significantly positive

  2. APC/C-mediated degradation of dsRNA-binding protein 4 (DRB4 involved in RNA silencing.

    Directory of Open Access Journals (Sweden)

    Katia Marrocco

    Full Text Available BACKGROUND: Selective protein degradation via the ubiquitin-26S proteasome is a major mechanism underlying DNA replication and cell division in all Eukaryotes. In particular, the APC/C (Anaphase Promoting Complex or Cyclosome is a master ubiquitin protein ligase (E3 that targets regulatory proteins for degradation allowing sister chromatid separation and exit from mitosis. Interestingly, recent work also indicates that the APC/C remains active in differentiated animal and plant cells. However, its role in post-mitotic cells remains elusive and only a few substrates have been characterized. METHODOLOGY/PRINCIPAL FINDINGS: In order to identify novel APC/C substrates, we performed a yeast two-hybrid screen using as the bait Arabidopsis APC10/DOC1, one core subunit of the APC/C, which is required for substrate recruitment. This screen identified DRB4, a double-stranded RNA binding protein involved in the biogenesis of different classes of small RNA (sRNA. This protein interaction was further confirmed in vitro and in plant cells. Moreover, APC10 interacts with DRB4 through the second dsRNA binding motif (dsRBD2 of DRB4, which is also required for its homodimerization and binding to its Dicer partner DCL4. We further showed that DRB4 protein accumulates when the proteasome is inactivated and, most importantly, we found that DRB4 stability depends on APC/C activity. Hence, depletion of Arabidopsis APC/C activity by RNAi leads to a strong accumulation of endogenous DRB4, far beyond its normal level of accumulation. However, we could not detect any defects in sRNA production in lines where DRB4 was overexpressed. CONCLUSIONS/SIGNIFICANCE: Our work identified a first plant substrate of the APC/C, which is not a regulator of the cell cycle. Though we cannot exclude that APC/C-dependent degradation of DRB4 has some regulatory roles under specific growth conditions, our work rather points to a housekeeping function of APC/C in maintaining precise cellular

  3. Glycogen synthase kinase-3-mediated phosphorylation of serine 73 targets sterol response element binding protein-1c (SREBP-1c) for proteasomal degradation.

    Science.gov (United States)

    Dong, Qingming; Giorgianni, Francesco; Beranova-Giorgianni, Sarka; Deng, Xiong; O'Meally, Robert N; Bridges, Dave; Park, Edwards A; Cole, Robert N; Elam, Marshall B; Raghow, Rajendra

    2016-01-01

    Sterol regulatory element binding protein-1c (SREBP-1c) is a key transcription factor that regulates genes involved in the de novo lipid synthesis and glycolysis pathways. The structure, turnover and transactivation potential of SREBP-1c are regulated by macronutrients and hormones via a cascade of signalling kinases. Using MS, we have identified serine 73 as a novel glycogen synthase kinase-3 (GSK-3) phosphorylation site in the rat SREBP-1c purified from McA-RH7777 hepatoma cells. Our site-specific mutagenesis strategy revealed that the turnover of SREBP-1c, containing wild type, phospho-null (serine to alanine) or phospho-mimetic (serine to aspartic acid) substitutions, was differentially regulated. We show that the S73D mutant of pSREBP-1c, that mimicked a state of constitutive phosphorylation, dissociated from the SREBP-1c-SCAP complex more readily and underwent GSK-3-dependent proteasomal degradation via SCF(Fbw7) ubiquitin ligase pathway. Pharmacologic inhibition of GSK-3 or knockdown of GSK-3 by siRNA prevented accelerated degradation of SREBP-1c. As demonstrated by MS, SREBP-1c was phosphorylated in vitro by GSK-3β at serine 73. Phosphorylation of serine 73 also occurs in the intact liver. We propose that GSK-3-mediated phosphorylation of serine 73 in the rat SREBP-1c and its concomitant destabilization represents a novel mechanism involved in the inhibition of de novo lipid synthesis in the liver. PMID:26589965

  4. Identification of a Cullin5-ElonginB-ElonginC E3 complex in degradation of feline immunodeficiency virus Vif-mediated feline APOBEC3 proteins.

    Science.gov (United States)

    Wang, Jiawen; Zhang, Wenyan; Lv, Mingyu; Zuo, Tao; Kong, Wei; Yu, Xianghui

    2011-12-01

    Various feline APOBEC3 (fA3) proteins exhibit broad antiviral activities against a wide range of viruses, such as feline immunodeficiency virus (FIV), feline foamy virus (FFV), and feline leukemia virus (FeLV), as well as those of other species. This activity can be counteracted by the FIV Vif protein, but the mechanism by which FIV Vif suppresses fA3s is unknown. In the present study, we demonstrated that FIV Vif could act via a proteasome-dependent pathway to overcome fA3s. FIV Vif interacted with feline cellular proteins Cullin5 (Cul5), ElonginB, and ElonginC to form an E3 complex to induce degradation of fA3s. Both the dominant-negative Cul5 mutant and a C-terminal hydrophilic replacement ElonginC mutant potently disrupted the FIV Vif activity against fA3s. Furthermore, we identified a BC-box motif in FIV Vif that was essential for the recruitment of E3 ubiquitin ligase and also required for FIV Vif-mediated degradation of fA3s. Moreover, despite the lack of either a Cul5-box or a HCCH zinc-binding motif, FIV Vif specifically selected Cul5. Therefore, FIV Vif may interact with Cul5 via a novel mechanism. These finding imply that SOCS proteins may possess distinct mechanisms to bind Cul5 during formation of the Elongin-Cullin-SOCS box complex. PMID:21957297

  5. Autophagy and ubiquitin-mediated proteolysis may not be involved in the degradation of spermatozoon mitochondria in mouse and porcine early embryos.

    Science.gov (United States)

    Jin, Yong-Xun; Zheng, Zhong; Yu, Xian-Feng; Zhang, Jia-Bao; Namgoong, Suk; Cui, Xiang-Shun; Hyun, Sang-Hwan; Kim, Nam-Hyung

    2016-02-01

    The mitochondrial genome is maternally inherited in animals, despite the fact that paternal mitochondria enter oocytes during fertilization. Autophagy and ubiquitin-mediated degradation are responsible for the elimination of paternal mitochondria in Caenorhabditis elegans; however, the involvement of these two processes in the degradation of paternal mitochondria in mammals is not well understood. We investigated the localization patterns of light chain 3 (LC3) and ubiquitin in mouse and porcine embryos during preimplantation development. We found that LC3 and ubiquitin localized to the spermatozoon midpiece at 3 h post-fertilization, and that both proteins were colocalized with paternal mitochondria and removed upon fertilization during the 4-cell stage in mouse and the zygote stage in porcine embryos. Sporadic paternal mitochondria were present beyond the morula stage in the mouse, and paternal mitochondria were restricted to one blastomere of 4-cell embryos. An autophagy inhibitor, 3-methyladenine (3-MA), did not affect the distribution of paternal mitochondria compared with the positive control, while an autophagy inducer, rapamycin, accelerated the removal of paternal mitochondria compared with the control. After the intracytoplasmic injection of intact spermatozoon into mouse oocytes, LC3 and ubiquitin localized to the spermatozoon midpiece, but remnants of undegraded paternal mitochondria were retained until the blastocyst stage. Our results show that paternal mitochondria colocalize with autophagy receptors and ubiquitin and are removed after in vitro fertilization, but some remnants of sperm mitochondrial sheath may persist up to morula stage after intracytoplasmic spermatozoon injection (ICSI). PMID:25513816

  6. ESCRT-0 dysfunction compromises autophagic degradation of protein aggregates and facilitates ER stress-mediated neurodegeneration via apoptotic and necroptotic pathways

    Science.gov (United States)

    Oshima, Ryuji; Hasegawa, Takafumi; Tamai, Keiichi; Sugeno, Naoto; Yoshida, Shun; Kobayashi, Junpei; Kikuchi, Akio; Baba, Toru; Futatsugi, Akira; Sato, Ikuro; Satoh, Kennichi; Takeda, Atsushi; Aoki, Masashi; Tanaka, Nobuyuki

    2016-01-01

    Endosomal sorting required for transport (ESCRT) complexes orchestrate endo-lysosomal sorting of ubiquitinated proteins, multivesicular body formation and autophagic degradation. Defects in the ESCRT pathway have been implicated in many neurodegenerative diseases, but the underlying molecular mechanisms that link them to neurodegeneration remain unknown. In this study, we showed that forebrain-specific ablation of ESCRT-0/Hrs induced marked hippocampal neuronal cell loss accompanied by the accumulation of ubiquitinated proteins, including α-synuclein, TDP-43 and huntingtin as well as the autophagic substrate SQSTM1/p62. Consistent with this, silencing of Hrs in cultured cells not only led to α-synuclein and TDP-43 accumulation in addition to impaired autophagic flux but also suppressed cell viability through the induction of ER stress followed by the activation of JNK and RIPK1, a key regulator of necroptosis. Moreover, necrostatin-1, a specific inhibitor of RIPK1, and pan-caspase inhibitors partially reduced the neurotoxicity in the Hrs-silenced cells. Altogether, these findings suggest that the disruption of ESCRT-0/Hrs in the nervous system compromises autophagic/lysosomal degradation of neurodegenerative disease-related proteins, which thereby triggers ER stress-mediated apoptotic and necroptotic cell death. PMID:27112194

  7. [6]-Shogaol Inhibits α-MSH-Induced Melanogenesis through the Acceleration of ERK and PI3K/Akt-Mediated MITF Degradation

    Directory of Open Access Journals (Sweden)

    Huey-Chun Huang

    2014-01-01

    Full Text Available [6]-Shogaol is the main biologically active component of ginger. Previous reports showed that [6]-shogaol has several pharmacological characteristics, such as antioxidative, anti-inflammatory, antimicrobial, and anticarcinogenic properties. However, the effects of [6]-shogaol on melanogenesis remain to be elucidated. The study aimed to evaluate the potential skin whitening mechanisms of [6]-shogaol. The effects of [6]-shogaol on cell viability, melanin content, tyrosinase activity, and the expression of the tyrosinase and microphthalmia-associated transcription factor (MITF were measured. The results revealed that [6]-shogaol effectively suppresses tyrosinase activity and the amount of melanin and that those effects are more pronounced than those of arbutin. It was also found that [6]-shogaol decreased the protein expression levels of tyrosinase-related protein 1 (TRP-1 and microphthalmia-associated transcriptional factor (MITF. In addition, the MITF mRNA levels were also effectively decreased in the presence of 20 μM [6]-shogaol. The degradation of MITF protein was inhibited by the MEK 1-inhibitor (U0126 or phosphatidylinositol-3-kinase inhibitor (PI3K inhibitor (LY294002. Further immunofluorescence staining assay implied the involvement of the proteasome in the downregulation of MITF by [6]-shogaol. Our confocal assay results also confirmed that [6]-shogaol inhibited α-melanocyte stimulating hormone- (α-MSH- induced melanogenesis through the acceleration of extracellular responsive kinase (ERK and phosphatidylinositol-3-kinase- (PI3K/Akt- mediated MITF degradation.

  8. Nonsense mutations in the rhodopsin gene that give rise to mild phenotypes trigger mRNA degradation in human cells by nonsense-mediated decay.

    Science.gov (United States)

    Roman-Sanchez, Ramon; Wensel, Theodore G; Wilson, John H

    2016-04-01

    Eight different nonsense mutations in the human rhodopsin gene cause retinitis pigmentosa (RP), an inherited degenerative disease of the retina that can lead to complete blindness. Although all these nonsense mutations lead to premature termination codons (PTCs) in rhodopsin mRNA, some display dominant inheritance, while others are recessive. Because nonsense-mediated decay (NMD) can degrade mRNAs containing PTCs and modulate the inheritance patterns of genetic diseases, we asked whether any of the nonsense mutations in the rhodopsin gene generated mRNAs that were susceptible to degradation by NMD. We hypothesized that nonsense mutations that caused mild RP phenotypes would trigger NMD, whereas those that did not engage NMD would cause more severe RP phenotypes-presumably due to the toxicity of the truncated protein. To test our hypothesis, we transfected human rhodopsin nonsense mutants into HEK293 and HT1080 human cells and measured transcript levels by qRT-PCR. In both cell lines, rhodopsin mutations Q64X and Q344X, which cause severe phenotypes that are dominantly inherited, yielded the same levels of rhodopsin mRNA as wild type. By contrast, rhodopsin mutations W161X and E249X, which cause recessive RP, showed decreased rhodopsin mRNA levels, consistent with NMD. Rhodopsin mutant Y136X, a dominant mutation that causes late-onset RP with a very mild pathology, also gave lower mRNA levels. Treatment of cells with Wortmannin, an inhibitor of NMD, eliminated the degradation of Y136X, W161X, and E249X rhodopsin mRNAs. These results suggest that NMD modulates the severity of RP in patients with nonsense mutations in the rhodopsin gene. PMID:26416182

  9. Endothelial SIRT1 prevents adverse arterial remodeling by facilitating HERC2-mediated degradation of acetylated LKB1

    DEFF Research Database (Denmark)

    Bai, Bo; Man, Andy W C; Yang, Kangmin;

    2016-01-01

    prevention of vascular ageing. Methods and Results-Co-immunoprecipitation assay demonstrated that SIRT1, via its amino-terminus, binds to the DOC domain of HERC2 [HECT and RLD domain containing E3 ubiquitin protein ligase 2], which then ubiquitinates LKB1 in the nuclear compartment of endothelial cells. Site......-directed mutagenesis revealed that acetylation at lysine (K) 64 of LKB1 triggers the formation of SIRT1/HERC2/LKB1 protein complex and subsequent proteasomal degradation. In vitro cellular studies suggested that accumulation of acetylated LKB1 in the nucleus leads to endothelial activation, in turn stimulating the...... proliferation of vascular smooth muscle cells and the production of extracellular matrix proteins. Chromatin immunoprecipitation quantitative PCR confirmed that acetylated LKB1 interacts with and activates TGFβ1 promoter, which is inhibited by SIRT1. Knocking down either SIRT1 or HERC2 results in an increased...

  10. Degradation of cytokinins by maize cytokinin dehydrogenase is mediated by free radicals generated by enzymatic oxidation of natural benzoxazinones.

    Science.gov (United States)

    Frébortová, Jitka; Novák, Ondrej; Frébort, Ivo; Jorda, Radek

    2010-02-01

    Hydroxamic acid 2,4-dihydroxy-7-methoxy-1,4-benzoxazin-one (DIMBOA) was isolated from maize phloem sap as a compound enhancing the degradation of isopentenyl adenine by maize cytokinin dehydrogenase (CKX), after oxidative conversion by either laccase or peroxidase. Laccase and peroxidase catalyze oxidative cleavage of DIMBOA to 4-nitrosoresorcinol-1-monomethyl ether (coniferron), which serves as a weak electron acceptor of CKX. The oxidation of DIMBOA and coniferron generates transitional free radicals that are used by CKX as effective electron acceptors. The function of free radicals in the CKX-catalyzed reaction was also verified with a stable free radical of 2,2'-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid. Application of exogenous cytokinin to maize seedlings resulted in an enhanced benzoxazinoid content in maize phloem sap. The results indicate a new function for DIMBOA in the metabolism of the cytokinin group of plant hormones. PMID:19912568

  11. Peptide-Mediated Tumor Targeting by a Degradable Nano Gene Delivery Vector Based on Pluronic-Modified Polyethylenimine

    Science.gov (United States)

    Wu, Zhaoyong; Zhan, Shuyu; Fan, Wei; Ding, Xueying; Wu, Xin; Zhang, Wei; Fu, Yinghua; Huang, Yueyan; Huang, Xuan; Chen, Rubing; Li, Mingjuan; Xu, Ningyin; Zheng, Yongxia; Ding, Baoyue

    2016-03-01

    Polyethylenimine (PEI) is considered to be a promising non-viral gene delivery vector. To solve the toxicity versus efficacy and tumor-targeting challenges of PEI used as gene delivery vector, we constructed a novel non-viral vector DR5-TAT-modified Pluronic-PEI (Pluronic-PEI-DR5-TAT), which was based on the attachment of low-molecular-weight polyethylenimine (LMW-PEI) to the amphiphilic polymer Pluronic to prepare Pluronic-modified LMW-PEI (Pluronic-PEI). This was then conjugated to a multifunctional peptide containing a cell-penetrating peptide (TAT) and a synthetic peptide that would bind to DR5—a receptor that is overexpressed in cancer cells. The vector showed controlled degradation, favorable DNA condensation and protection performance. The Pluronic-PEI-DR5-TAT/DNA complexes at an N/P ratio of 15:1 were spherical nanoparticles of 122 ± 11.6 nm and a zeta potential of about 22 ± 2.8 mV. In vitro biological characterization results indicated that Pluronic-PEI-DR5-TAT/DNA complexes had a higher specificity for the DR5 receptor and were taken up more efficiently by tumor cells than normal cells, compared to complexes formed with PEI 25 kDa or Pluronic-PEI. Thus, the novel complexes showed much lower cytotoxicity to normal cells and higher gene transfection efficiency in tumor cells than that exhibited by PEI 25 kDa and Pluronic-PEI. In summary, our novel, degradable non-viral tumor-targeting vector is a promising candidate for use in gene therapy.

  12. Effect of reaction conditions on methyl red degradation mediated by boron and nitrogen doped TiO{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Galenda, A., E-mail: galenda@ieni.cnr.it [CNR-IENI, Istituto per l’Energetica e le Interfasi, Corso Stati Uniti, 4 35127 Padova (Italy); Crociani, L.; Habra, N. El; Favaro, M. [CNR-IENI, Istituto per l’Energetica e le Interfasi, Corso Stati Uniti, 4 35127 Padova (Italy); Natile, M.M. [CNR-IENI, Istituto per l’Energetica e le Interfasi, Dipartimento di Scienze Chimiche, Università di Padova, via F. Marzolo, 1 35131 Padova (Italy); Rossetto, G. [CNR-IENI, Istituto per l’Energetica e le Interfasi, Corso Stati Uniti, 4 35127 Padova (Italy)

    2014-09-30

    Highlights: • Boron and/or nitrogen-doped TiO{sub 2} for photocatalytic wastewater treatment. • Methyl red degradation/mineralisation as a function of pH, acids and dopants. • Adsorption time influence on photocatalytic process. • Recovery of worn-out catalyst. - Abstract: Nowadays the employment of renewable and sustainable energy sources, and solar light as main option, becomes an urgent need. Photocatalytic processes received great attention in wastewater treatment due to their cheapness, environmental compatibility and optimal performances. Despite the general low selectivity of the photocatalysts, an accurate optimisation of the operational parameters needs to be carried out in order to maximise the process yield. Because of this reason, the present contribution aims to deepen either the knowledge in boron and/or nitrogen doped TiO{sub 2}-based systems and their employment in methyl red removal from aqueous solutions. The samples were obtained by coprecipitation and characterised by XRD, SEM, BET specific surface area, UV–vis and XPS techniques. The catalytic activity was for the first time carefully evaluated with respect to methyl red photodegradation in different conditions as a function of working pH, counter-ions and pre-adsorption time. An ad-hoc study was performed on the importance of the pre-adsorption of the dye, suggesting that an extended adsorption is useless for the catalyst photoactivity, while a partial coverage is preferable. The photocatalytic tests demonstrate the positive influence of boron doping in photo-activated reactions and the great importance of the operational parameters with respect to the simple methyl red bleaching rather than the overall pollutant mineralisation. It is proved, indeed, that different working pH, acidifying means and substrate pre-adsorption time can enhance or limit the catalyst performances with respect to the complete pollutant degradation rather than its partial breakage.

  13. Peptide-Mediated Tumor Targeting by a Degradable Nano Gene Delivery Vector Based on Pluronic-Modified Polyethylenimine.

    Science.gov (United States)

    Wu, Zhaoyong; Zhan, Shuyu; Fan, Wei; Ding, Xueying; Wu, Xin; Zhang, Wei; Fu, Yinghua; Huang, Yueyan; Huang, Xuan; Chen, Rubing; Li, Mingjuan; Xu, Ningyin; Zheng, Yongxia; Ding, Baoyue

    2016-12-01

    Polyethylenimine (PEI) is considered to be a promising non-viral gene delivery vector. To solve the toxicity versus efficacy and tumor-targeting challenges of PEI used as gene delivery vector, we constructed a novel non-viral vector DR5-TAT-modified Pluronic-PEI (Pluronic-PEI-DR5-TAT), which was based on the attachment of low-molecular-weight polyethylenimine (LMW-PEI) to the amphiphilic polymer Pluronic to prepare Pluronic-modified LMW-PEI (Pluronic-PEI). This was then conjugated to a multifunctional peptide containing a cell-penetrating peptide (TAT) and a synthetic peptide that would bind to DR5-a receptor that is overexpressed in cancer cells. The vector showed controlled degradation, favorable DNA condensation and protection performance. The Pluronic-PEI-DR5-TAT/DNA complexes at an N/P ratio of 15:1 were spherical nanoparticles of 122 ± 11.6 nm and a zeta potential of about 22 ± 2.8 mV. In vitro biological characterization results indicated that Pluronic-PEI-DR5-TAT/DNA complexes had a higher specificity for the DR5 receptor and were taken up more efficiently by tumor cells than normal cells, compared to complexes formed with PEI 25 kDa or Pluronic-PEI. Thus, the novel complexes showed much lower cytotoxicity to normal cells and higher gene transfection efficiency in tumor cells than that exhibited by PEI 25 kDa and Pluronic-PEI. In summary, our novel, degradable non-viral tumor-targeting vector is a promising candidate for use in gene therapy. PMID:26932761

  14. Notch Signaling Activates Stem Cell Properties of Müller Glia through Transcriptional Regulation and Skp2-mediated Degradation of p27Kip1

    Science.gov (United States)

    Parameswaran, Sowmya; Mathews, Saumi; Xia, Xiaohuan; Zheng, Li; Neville, Andrew J.; Ahmad, Iqbal

    2016-01-01

    Müller glia (MG), the sole glial cells generated by retinal progenitors, have emerged as a viable cellular target for therapeutic regeneration in degenerative blinding diseases, as they possess dormant stem cell properties. However, the mammalian MG does not display the neurogenic potential of their lower vertebrate counterparts, precluding their practical clinical use. The answer to this barrier may be found in two interlinked processes underlying the neurogenic potential, i.e., the activation of the dormant stem cell properties of MG and their differentiation along the neuronal lineage. Here, we have focused on the former and examined Notch signaling-mediated activation of MG. We demonstrate that one of the targets of Notch signaling is the cyclin-dependent kinase inhibitor (CKI), p27Kip1, which is highly expressed in quiescent MG. Notch signaling facilitates the activation of MG by inhibiting p27Kip1 expression. This is likely achieved through the Notch- p27Kip1 and Notch-Skp2-p27Kip1 axes, the former inhibiting the expression of p27Kip1 transcripts and the latter levels of p27Kip1 proteins by Skp2-mediated proteasomal degradation. Thus, Notch signaling may facilitate re-entry of MG into the cell cycle by inhibiting p27Kip1 expression both transcriptionally and post-translationally. PMID:27011052

  15. Leptospira interrogans Lsa23 protein recruits plasminogen, factor H and C4BP from normal human serum and mediates C3b and C4b degradation.

    Science.gov (United States)

    Siqueira, Gabriela H; Atzingen, Marina V; de Souza, Gisele O; Vasconcellos, Silvio A; Nascimento, Ana L T O

    2016-02-01

    It has been reported that pathogenic Leptospira are resistant to normal human serum (NHS) due to their ability to evade the complement immune system by interacting with factor H (FH) and C4b-binding protein (C4BP) regulators. Moreover, plasmin generation on the leptospiral surface diminishes C3b and IgG deposition, decreasing opsonophagocytosis by immune competent cells. We have previously reported that Lsa23 (LIC11360) is a multipurpose protein capable of binding purified extracellular matrix molecules, FH, C4BP and plasminogen (PLG)/plasmin in the presence of PLG activators. In this work, we provide further evidence that Lsa23 is located at the bacterial surface by using immunofluorescence microscopy. We show that Lsa23 has the ability to acquire FH, C4BP and PLG from NHS, and use these interactions to evade innate immunity. The binding with the complement regulators FH and C4BP preserves factor I (FI) activity, leading to C3b and C4b degradation products, respectively. C3b and C4b alpha-chain cleavage was also observed when Lsa23 bound to PLG generating plasmin, an effect blocked by the protease inhibitor aprotinin. Lsa23 also inhibited lytic activity by NHS mediated by both classical and alternative complement pathways. Thus, Lsa23 has the ability to block both pathways of the complement system, and may help pathogenic Leptospira to escape complement-mediated clearance in human hosts. Indeed, NHS treated with Lsa23 confers a partial serum resistance phenotype to Leptospira biflexa, whereas blocking this protein with anti-Lsa23 renders pathogenic L. interrogans more susceptible to complement-mediated killing. Thus, Lsa23 is a multifunctional protein involved in many pathways, featuring C4b cleavage by plasmin, knowledge that may help in the development of preventive approaches to intervene with human complement escape by this versatile pathogen. PMID:26614523

  16. Vpu-mediated CD4 down-regulation and degradation is conserved among highly divergent SIVcpz strains

    International Nuclear Information System (INIS)

    Human immunodeficiency virus type 1 (HIV-1) along with simian immunodeficiency viruses from chimpanzees (SIVcpz) and three species of Old World monkeys from the genus Cercopithecus have been shown to encode a Vpu protein. To date, the functional characterization of Vpu has been limited to a small number of subtype B and more recently subtype C Vpu proteins. Using a recently developed VpuEGFP reporter system, we have shown that the subtype B and C Vpus are capable of preventing CD4 from being expressed on the cell surface. Using the same reporter system, we report here on the expression and functional analysis of Vpu protein from four SIVcpz isolates (CAM13, ANT, TAN1, and GAB1). All four SIV Vpu fusion proteins were efficiently expressed and prevented CD4 expression on the cell surface and induced CD4 degradation. This was surprising as three of the SIVcpz Vpu fusion proteins had only one canonical casein kinase II (CK-II) site (CAM13, ANT, TAN1) while previous studies with laboratory adapted HXB2 had indicated that both CK-II sites were required for CD4 degradation. Both ANT and TAN1 Vpu sequences encoded five consecutive negatively charged amino acids residues following the only CKII site (SAIEEDEE for ANT; SGVEEDEE for TAN1). We thus explored the possibility that this stretch of negatively charged amino acids might substitute for the lack of second CK-II site. Substitution of the aspartic acid at position 61 and glutamic acid at position 63 in the SIVcpz ANT Vpu within with lysine residues abolished the ability of this protein to down-modulate cell surface expression of CD4. Similarly, change of a serine to an alanine residue following the single consensus CK-II site of the CAM13 Vpu (SGNESDGGEEE) abolished CD4-down-regulation, suggesting that this serine was phosphorylated in the absence of a canonical CK-II site. Our results indicate that the serine was required, suggesting that this serine was phosphorylated by CK-II or possibly another cellular kinase. Taken

  17. Cathepsin B is up-regulated and mediates extracellular matrix degradation in trabecular meshwork cells following phagocytic challenge.

    Directory of Open Access Journals (Sweden)

    Kristine Porter

    Full Text Available Cells in the trabecular meshwork (TM, a tissue responsible for draining aqueous humor out of the eye, are known to be highly phagocytic. Phagocytic activity in TM cells is thought to play an important role in outflow pathway physiology. However, the molecular mechanisms triggered by phagocytosis in TM cells are unknown. Here we investigated the effects of chronic phagocytic stress on lysosomal function using different phagocytic ligands (E. coli, carboxylated beads, collagen I-coated beads, and pigment. Lysotracker red co-localization and electron micrographs showed the maturation of E. coli- and collagen I-coated beads-containing phagosomes into phagolysosomes. Maturation of phagosomes into phagolysosomes was not observed with carboxylated beads or pigment particles. In addition, phagocytosis of E. coli and collagen I-coated beads led to increased lysosomal mass, and the specific up-regulation and activity of cathepsin B (CTSB. Higher levels of membrane-bound and secreted CTSB were also detected. Moreover, in vivo zymography showed the intralysosomal degradation of ECM components associated with active CTSB, as well as an overall increased gelatinolytic activity in phagocytically challenged TM cells. This increased gelatinolytic activity with phagocytosis was partially blocked with an intracellular CTSB inhibitor. Altogether, these results suggest a potential role of phagocytosis in outflow pathway tissue homeostasis through the up-regulation and/or proteolytic activation of extracellular matrix remodeling genes.

  18. Insulin-degrading enzyme secretion from astrocytes is mediated by an autophagy-based unconventional secretory pathway in Alzheimer disease.

    Science.gov (United States)

    Son, Sung Min; Cha, Moon-Yong; Choi, Heesun; Kang, Seokjo; Choi, Hyunjung; Lee, Myung-Shik; Park, Sun Ah; Mook-Jung, Inhee

    2016-05-01

    The secretion of proteins that lack a signal sequence to the extracellular milieu is regulated by their transition through the unconventional secretory pathway. IDE (insulin-degrading enzyme) is one of the major proteases of amyloid beta peptide (Aβ), a presumed causative molecule in Alzheimer disease (AD) pathogenesis. IDE acts in the extracellular space despite having no signal sequence, but the underlying mechanism of IDE secretion extracellularly is still unknown. In this study, we found that IDE levels were reduced in the cerebrospinal fluid (CSF) of patients with AD and in pathology-bearing AD-model mice. Since astrocytes are the main cell types for IDE secretion, astrocytes were treated with Aβ. Aβ increased the IDE levels in a time- and concentration-dependent manner. Moreover, IDE secretion was associated with an autophagy-based unconventional secretory pathway, and depended on the activity of RAB8A and GORASP (Golgi reassembly stacking protein). Finally, mice with global haploinsufficiency of an essential autophagy gene, showed decreased IDE levels in the CSF in response to an intracerebroventricular (i.c.v.) injection of Aβ. These results indicate that IDE is secreted from astrocytes through an autophagy-based unconventional secretory pathway in AD conditions, and that the regulation of autophagy is a potential therapeutic target in addressing Aβ pathology. PMID:26963025

  19. AntR-mediated bidirectional activation of antA and antR, anthranilate degradative genes in Pseudomonas aeruginosa.

    Science.gov (United States)

    Kim, Soo-Kyoung; Im, Su-Jin; Yeom, Doo-Hwan; Lee, Joon-Hee

    2012-08-15

    Bidirectional activation of transcription is a peculiar regulation mode of gene expression. In this study, we show that genes involved in the metabolism of anthranilate, a precursor of biosynthesis of tryptophan and Pseudomonas quinolone signal (PQS) are regulated by this bidirectional activation of transcription. Anthranilate is degraded by anthranilate dioxygenase complex encoded by antABC operon, and AntR, a LysR-type regulator encoded by antR activates the transcription of antABC operon in the presence of anthranilate. In P. aeruginosa, antABC and antR are divergently located and AntR binds to the intergenic region between antA and antR to activate the antABC transcription. In this study, we determined the transcriptional start site of the antA promoter (antA(p)) and AntR-responsive elements (AREs) in P. aeruginosa. The upstream deletion analysis of antA(p) and in vitro gel shift assay with purified AntR showed that there are two AREs at -194 to -148 and -88 to -47 regions. We also found that AntR activates antR promoter (antR(p)) in the opposite direction and both AREs are important in the bidirectional activation of antA(p) and antR(p). Two AREs have different binding affinities to AntR and the strength of transcriptional activation was dramatically asymmetric depending on the direction. We suggest that the different affinities of two AREs may explain the asymmetry of the bidirectional activation by AntR. PMID:22609066

  20. Effect of reaction conditions on methyl red degradation mediated by boron and nitrogen doped TiO2

    Science.gov (United States)

    Galenda, A.; Crociani, L.; Habra, N. El; Favaro, M.; Natile, M. M.; Rossetto, G.

    2014-09-01

    Nowadays the employment of renewable and sustainable energy sources, and solar light as main option, becomes an urgent need. Photocatalytic processes received great attention in wastewater treatment due to their cheapness, environmental compatibility and optimal performances. Despite the general low selectivity of the photocatalysts, an accurate optimisation of the operational parameters needs to be carried out in order to maximise the process yield. Because of this reason, the present contribution aims to deepen either the knowledge in boron and/or nitrogen doped TiO2-based systems and their employment in methyl red removal from aqueous solutions. The samples were obtained by coprecipitation and characterised by XRD, SEM, BET specific surface area, UV-vis and XPS techniques. The catalytic activity was for the first time carefully evaluated with respect to methyl red photodegradation in different conditions as a function of working pH, counter-ions and pre-adsorption time. An ad-hoc study was performed on the importance of the pre-adsorption of the dye, suggesting that an extended adsorption is useless for the catalyst photoactivity, while a partial coverage is preferable. The photocatalytic tests demonstrate the positive influence of boron doping in photo-activated reactions and the great importance of the operational parameters with respect to the simple methyl red bleaching rather than the overall pollutant mineralisation. It is proved, indeed, that different working pH, acidifying means and substrate pre-adsorption time can enhance or limit the catalyst performances with respect to the complete pollutant degradation rather than its partial breakage.

  1. Steviol reduces MDCK Cyst formation and growth by inhibiting CFTR channel activity and promoting proteasome-mediated CFTR degradation.

    Directory of Open Access Journals (Sweden)

    Chaowalit Yuajit

    Full Text Available Cyst enlargement in polycystic kidney disease (PKD involves cAMP-activated proliferation of cyst-lining epithelial cells and transepithelial fluid secretion into the cyst lumen via cystic fibrosis transmembrane conductance regulator (CFTR chloride channel. This study aimed to investigate an inhibitory effect and detailed mechanisms of steviol and its derivatives on cyst growth using a cyst model in Madin-Darby canine kidney (MDCK cells. Among 4 steviol-related compounds tested, steviol was found to be the most potent at inhibiting MDCK cyst growth. Steviol inhibition of cyst growth was dose-dependent; steviol (100 microM reversibly inhibited cyst formation and cyst growth by 72.53.6% and 38.2±8.5%, respectively. Steviol at doses up to 200 microM had no effect on MDCK cell viability, proliferation and apoptosis. However, steviol acutely inhibited forskolin-stimulated apical chloride current in MDCK epithelia, measured with the Ussing chamber technique, in a dose-dependent manner. Prolonged treatment (24 h with steviol (100 microM also strongly inhibited forskolin-stimulated apical chloride current, in part by reducing CFTR protein expression in MDCK cells. Interestingly, proteasome inhibitor, MG-132, abolished the effect of steviol on CFTR protein expression. Immunofluorescence studies demonstrated that prolonged treatment (24 h with steviol (100 microM markedly reduced CFTR expression at the plasma membrane. Taken together, the data suggest that steviol retards MDCK cyst progression in two ways: first by directly inhibiting CFTR chloride channel activity and second by reducing CFTR expression, in part, by promoting proteasomal degradation of CFTR. Steviol and related compounds therefore represent drug candidates for treatment of polycystic kidney disease.

  2. Targeted polypeptide degradation

    Science.gov (United States)

    Church, George M.; Janse, Daniel M.

    2008-05-13

    This invention pertains to compositions, methods, cells and organisms useful for selectively localizing polypeptides to the proteasome for degradation. Therapeutic methods and pharmaceutical compositions for treating disorders associated with the expression and/or activity of a polypeptide by targeting these polypeptides for degradation, as well as methods for targeting therapeutic polypeptides for degradation and/or activating therapeutic polypeptides by degradation are provided. The invention provides methods for identifying compounds that mediate proteasome localization and/or polypeptide degradation. The invention also provides research tools for the study of protein function.

  3. The CCR4-NOT complex mediates deadenylation and degradation of stem cell mRNAs and promotes planarian stem cell differentiation.

    Science.gov (United States)

    Solana, Jordi; Gamberi, Chiara; Mihaylova, Yuliana; Grosswendt, Stefanie; Chen, Chen; Lasko, Paul; Rajewsky, Nikolaus; Aboobaker, A Aziz

    2013-01-01

    Post-transcriptional regulatory mechanisms are of fundamental importance to form robust genetic networks, but their roles in stem cell pluripotency remain poorly understood. Here, we use freshwater planarians as a model system to investigate this and uncover a role for CCR4-NOT mediated deadenylation of mRNAs in stem cell differentiation. Planarian adult stem cells, the so-called neoblasts, drive the almost unlimited regenerative capabilities of planarians and allow their ongoing homeostatic tissue turnover. While many genes have been demonstrated to be required for these processes, currently almost no mechanistic insight is available into their regulation. We show that knockdown of planarian Not1, the CCR4-NOT deadenylating complex scaffolding subunit, abrogates regeneration and normal homeostasis. This abrogation is primarily due to severe impairment of their differentiation potential. We describe a stem cell specific increase in the mRNA levels of key neoblast genes after Smed-not1 knock down, consistent with a role of the CCR4-NOT complex in degradation of neoblast mRNAs upon the onset of differentiation. We also observe a stem cell specific increase in the frequency of longer poly(A) tails in these same mRNAs, showing that stem cells after Smed-not1 knock down fail to differentiate as they accumulate populations of transcripts with longer poly(A) tails. As other transcripts are unaffected our data hint at a targeted regulation of these key stem cell mRNAs by post-transcriptional regulators such as RNA-binding proteins or microRNAs. Together, our results show that the CCR4-NOT complex is crucial for stem cell differentiation and controls stem cell-specific degradation of mRNAs, thus providing clear mechanistic insight into this aspect of neoblast biology. PMID:24367277

  4. The CCR4-NOT complex mediates deadenylation and degradation of stem cell mRNAs and promotes planarian stem cell differentiation.

    Directory of Open Access Journals (Sweden)

    Jordi Solana

    Full Text Available Post-transcriptional regulatory mechanisms are of fundamental importance to form robust genetic networks, but their roles in stem cell pluripotency remain poorly understood. Here, we use freshwater planarians as a model system to investigate this and uncover a role for CCR4-NOT mediated deadenylation of mRNAs in stem cell differentiation. Planarian adult stem cells, the so-called neoblasts, drive the almost unlimited regenerative capabilities of planarians and allow their ongoing homeostatic tissue turnover. While many genes have been demonstrated to be required for these processes, currently almost no mechanistic insight is available into their regulation. We show that knockdown of planarian Not1, the CCR4-NOT deadenylating complex scaffolding subunit, abrogates regeneration and normal homeostasis. This abrogation is primarily due to severe impairment of their differentiation potential. We describe a stem cell specific increase in the mRNA levels of key neoblast genes after Smed-not1 knock down, consistent with a role of the CCR4-NOT complex in degradation of neoblast mRNAs upon the onset of differentiation. We also observe a stem cell specific increase in the frequency of longer poly(A tails in these same mRNAs, showing that stem cells after Smed-not1 knock down fail to differentiate as they accumulate populations of transcripts with longer poly(A tails. As other transcripts are unaffected our data hint at a targeted regulation of these key stem cell mRNAs by post-transcriptional regulators such as RNA-binding proteins or microRNAs. Together, our results show that the CCR4-NOT complex is crucial for stem cell differentiation and controls stem cell-specific degradation of mRNAs, thus providing clear mechanistic insight into this aspect of neoblast biology.

  5. Involvement of Bcl-xL degradation and mitochondrial-mediated apoptotic pathway in pyrrolizidine alkaloids-induced apoptosis in hepatocytes

    International Nuclear Information System (INIS)

    Pyrrolizidine alkaloids (PAs) are natural hepatotoxins with worldwide distribution in more than 6000 high plants including medicinal herbs or teas. The aim of this study is to investigate the signal pathway involved in PAs-induced hepatotoxicity. Our results showed that clivorine, isolated from Ligularia hodgsonii Hook, decreased cell viability and induced apoptosis in L-02 cells and mouse hepatocytes. Western-blot results showed that clivorine induced caspase-3/-9 activation, mitochondrial release of cytochrome c and decreased anti-apoptotic Bcl-xL in a time (8-48 h)- and concentration (1-100 μM)-dependent manner. Furthermore, inhibitors of pan-caspase, caspase-3 and caspase-9 significantly inhibited clivorine-induced apoptosis and rescued clivorine-decreased cell viability. Polyubiquitination of Bcl-xL was detected after incubation with 100 μM clivorine for 40 h in the presence of proteasome specific inhibitor MG132, indicating possible degradation of Bcl-xL protein. Furthermore, pretreatment with MG132 or calpain inhibitor I for 2 h significantly enhanced clivorine-decreased Bcl-xL level and cell viability. All the other tested PAs such as senecionine, isoline and monocrotaline decreased mouse hepatocytes viability in a concentration-dependent manner. Clivorine (10 μM) induced caspase-3 activation and decreased Bcl-xL was also confirmed in mouse hepatocytes. Meanwhile, another PA senecionine isolated from Senecio vulgaris L also induced apoptosis, caspase-3 activation and decreased Bcl-xL in mouse hepatocytes. In conclusion, our results suggest that PAs may share the same hepatotoxic signal pathway, which involves degradation of Bcl-xL protein and thus leading to the activation of mitochondrial-mediated apoptotic pathway

  6. Mn(2+)-mediated homogeneous Fenton-like reaction of Fe(III)-NTA complex for efficient degradation of organic contaminants under neutral conditions.

    Science.gov (United States)

    Li, Yifan; Sun, Jianhui; Sun, Sheng-Peng

    2016-08-01

    In this work, we report a novel Mn(2+)-mediated Fenton-like process based on Fe(III)-NTA complex that is super-efficient at circumneutral pH range. Kinetics experiments showed that the presence of Mn(2+) significantly enhanced the effectiveness of Fe(III)-NTA complex catalyzed Fenton-like reaction. The degradation rate constant of crotamiton (CRMT), a model compound, by the Fe(III)- NTA_Mn(2+) Fenton-like process was at least 1.6 orders of magnitude larger than that in the absence of Mn(2+). Other metal ions such as Ca(2+), Mg(2+), Co(2+) and Cu(2+) had no impacts or little inhibitory effect on the Fe(III)-NTA complex catalyzed Fenton-like reaction. The generation of hydroxyl radical (HO) and superoxide radical anion (O2(-)) in the Fe(III)-NTA_Mn(2+) Fenton-like process were suggested by radicals scavenging experiments. The degradation efficiency of CRMT was inhibited significantly (approximately 92%) by the addition of HO scavenger 2-propanol, while the addition of O2(-) scavenger chloroform resulted in 68% inhibition. Moreover, the results showed that other chelating agents such as EDTA- and s,s-EDDS-Fe(III) catalyzed Fenton-like reactions were also enhanced significantly by the presence of Mn(2+). The mechanism involves an enhanced generation of O2(-) from the reactions of Mn(2+)-chelates with H2O2, indirectly promoting the generation of HO by accelerating the reduction rate of Fe(III)-chelates to Fe(II)- chelates. PMID:27070388

  7. Imipramine blue halts head and neck cancer invasion through promoting F-box and leucine-rich repeat protein 14-mediated Twist1 degradation.

    Science.gov (United States)

    Yang, W-H; Su, Y-H; Hsu, W-H; Wang, C-C; Arbiser, J L; Yang, M-H

    2016-05-01

    The unique characteristic of head and neck squamous cell carcinoma (HNSCC) is that local invasion rather than distant metastasis is the major route for dissemination. Therefore, targeting the locally invasive cancer cells is more important than preventing systemic metastasis in HNSCC and other invasive-predominant cancers. We previously demonstrate a specific mechanism for HNSCC local invasion: the epithelial-mesenchymal transition (EMT) regulator Twist1 represses microRNA let-7i expression, leading to the activation of the small GTPase Rac1 and engendering the mesenchymal-mode movement in three-dimensional (3D) culture. However, targeting the EMT regulator is relatively difficult because of its transcription factor nature and the strategy for confining HNSCC invasion to facilitate local treatment is limited. Imipramine blue (IB) is a newly identified anti-invasive compound that effectively inhibits glioma invasion. Here we demonstrate that in HNSCC cells, a noncytotoxic dose of IB represses mesenchymal-mode migration in two-and-a-half-dimensional/3D culture system. IB suppresses EMT and stemness of HNSCC cells through inhibition of Twist1-mediated let-7i downregulation and Rac1 activation and the EMT signalling. Mechanistically, IB inhibits reactive oxygen species-induced nuclear factor-κB pathway activation. Importantly, IB promotes degradation of the EMT inducer Twist1 by enhancing F-box and leucine-rich repeat protein 14 (FBXL14)-mediated polyubiquitination of Twist1. Together, this study demonstrates the potent anti-invasion and EMT-inhibition effect of IB, suggesting the potential of IB in treating local invasion-predominant cancers. PMID:26257063

  8. Cocaine induces nuclear export and degradation of neuronal retinoid X receptor-γ via a TNF-α/JNK- mediated mechanism.

    Science.gov (United States)

    Kovalevich, Jane; Yen, William; Ozdemir, Ahmet; Langford, Dianne

    2015-03-01

    Cocaine abuse represents an immense societal health and economic burden for which no effective treatment currently exists. Among the numerous intracellular signaling cascades impacted by exposure to cocaine, increased and aberrant production of pro-inflammatory cytokines in the CNS has been observed. Additionally, we have previously reported a decrease in retinoid-X-receptor-gamma (RXR-γ) in brains of mice chronically exposed to cocaine. Through obligate heterodimerization with a number of nuclear receptors, RXRs serve as master regulatory transcription factors, which can potentiate or suppress expression of a wide spectrum of genes. Little is known about the regulation of RXR levels, but previous studies indicate cellular stressors such as cytokines negatively regulate levels of RXRs in vitro. To evaluate the mechanism underlying the cocaine-induced decreases in RXR-γ levels observed in vivo, we exposed neurons to cocaine in vitro and examined pathways which may contribute to disruption in RXR signaling, including activation of stress pathways by cytokine induction. In these studies, we provide the first evidence that cocaine exposure disrupts neuronal RXR-γ signaling in vitro by promoting its nuclear export and degradation. Furthermore, we demonstrate this effect may be mediated, at least in part, by cocaine-induced production of TNF-α and its downstream effector c-Jun-NH-terminal kinase (JNK). Findings from this study are therefore applicable to both cocaine abuse and to pathological conditions characterized by neuroinflammatory factors, such as neurodegenerative disease. PMID:25586717

  9. 格尔德霉素对肿瘤坏死因子诱导的PC-3M细胞中c-FLIP表达上调的影响%Influence of HSP90-inhibitor Geldanamycin on TNF-induced upregulation of cFLIP in PC-3M cells

    Institute of Scientific and Technical Information of China (English)

    曹军; 庞自力

    2006-01-01

    目的:探讨热休克蛋白90抑制剂格尔德霉素(Geldanamycin,GA)对TNF-α诱导的前列腺肿瘤细胞PC-3M中白介素-1β转换酶抑制蛋白(c-FLIP)上调的影响及意义.方法:分别用TNF-α和GA+TNF-α处理PC-3M细胞,用免疫细胞化学法测c-FLIP蛋白水平表达差异,采用RT-PCR测c-FLIP mRNA水平的表达差异.结果:使用TNF-α处理6小时后PC-3M细胞c-FLIP在蛋白及mRNA表达水平明显上调,而使用热休克蛋白90抑制剂GA预处理18小时后,能明显抑制TNF-α诱导的c-FLIP表达上调.结论:热休克蛋白90抑制剂能有效抑制TNF诱导的c-FLIP表达上调.

  10. Role of endoplasmic reticulum stress in alpha-TEA mediated TRAIL/DR5 death receptor dependent apoptosis.

    Directory of Open Access Journals (Sweden)

    Richa Tiwary

    Full Text Available BACKGROUND: Alpha-TEA (RRR-alpha-tocopherol ether-linked acetic acid analog, a derivative of RRR-alpha-tocopherol (vitamin E exhibits anticancer actions in vitro and in vivo in variety of cancer types. The objective of this study was to obtain additional insights into the mechanisms involved in alpha-TEA induced apoptosis in human breast cancer cells. METHODOLOGY/PRINCIPAL FINDINGS: alpha-TEA induces endoplasmic reticulum (ER stress as indicated by increased expression of CCAAT/enhancer binding protein homologous protein (CHOP as well as by enhanced expression or activation of specific markers of ER stress such as glucose regulated protein (GRP78, phosphorylated alpha subunit of eukaryotic initiation factor 2 (peIF-2alpha, and spliced XBP-1 mRNA. Knockdown studies using siRNAs to TRAIL, DR5, JNK and CHOP as well as chemical inhibitors of ER stress and caspase-8 showed that: i alpha-TEA activation of DR5/caspase-8 induces an ER stress mediated JNK/CHOP/DR5 positive amplification loop; ii alpha-TEA downregulation of c-FLIP (L protein levels is mediated by JNK/CHOP/DR5 loop via a JNK dependent Itch E3 ligase ubiquitination that further serves to enhance the JNK/CHOP/DR5 amplification loop by preventing c-FLIP's inhibition of caspase-8; and (iii alpha-TEA downregulation of Bcl-2 is mediated by the ER stress dependent JNK/CHOP/DR5 signaling. CONCLUSION: Taken together, ER stress plays an important role in alpha-TEA induced apoptosis by enhancing DR5/caspase-8 pro-apoptotic signaling and suppressing anti-apoptotic factors c-FLIP and Bcl-2 via ER stress mediated JNK/CHOP/DR5/caspase-8 signaling.

  11. Interaction between Human Serum Albumin and antidiabetic compounds and its influence on the O2((1)Δg)-mediated degradation of the protein.

    Science.gov (United States)

    Challier, C; Beassoni, P; Boetsch, C; García, N A; Biasutti, M A; Criado, S

    2015-01-01

    The complexity depicted by disease scenarios as diabetes mellitus, constitutes a very interesting field of study when drugs and biologically relevant components may be affected by such environments. In this report, the interaction between the protein Human Serum Albumin (HSA) and two antidiabetics (Andb), Gliclazide (Gli) and Glipizide (Glip) was studied through fluorescence and docking assays, in order to characterize these systems. On the basis that HSA and Andb can be exposed in vivo at high Reactive Oxygen Species (ROS) concentrations in diabetic patients, the degradative process of the protein free and bound to Andb, in presence of the species singlet molecular oxygen (O2((1)Δg)), was evaluated. Fluorescence and docking assays indicated that Gli, as well as Glip bind to HSA on two sites, with binding constants values in the order of 10(4)-10(5)M(-1). Likewise, docking assays revealed that the location of Gli or Glip on the protein may be the HSA binding sites II and III. Thermodynamic parameters showed that the interaction between HSA and Glip is a favored, enthalpically-controlled process. Oxygen uptake experiments indicated that Glip is less photooxidizable than Gli through a O2((1)Δg)-mediated process. Besides, the protein-Andb binding produced a decrease in the overall rate constant for O2((1)Δg) quenching as compared to the value for the free protein. This fact could be interpreted in terms of a reduction in the availability of Tyrosine residues in the bonded protein, with a concomitant decrease in the physical quenching deactivation of the oxidative species. PMID:25490375

  12. Role of SUMO in RNF4-mediated promyelocytic leukemia protein (PML) degradation: sumoylation of PML and phospho-switch control of its SUMO binding domain dissected in living cells.

    Science.gov (United States)

    Percherancier, Yann; Germain-Desprez, Delphine; Galisson, Frédéric; Mascle, Xavier H; Dianoux, Laurent; Estephan, Patricia; Chelbi-Alix, Mounira K; Aubry, Muriel

    2009-06-12

    Promyelocytic leukemia protein (PML) is a tumor suppressor acting as the organizer of subnuclear structures called PML nuclear bodies (NBs). Both covalent modification of PML by the small ubiquitin-like modifier (SUMO) and non-covalent binding of SUMO to the PML SUMO binding domain (SBD) are necessary for PML NB formation and maturation. PML sumoylation and proteasome-dependent degradation induced by the E3 ubiquitin ligase, RNF4, are enhanced by the acute promyelocytic leukemia therapeutic agent, arsenic trioxide (As2O3). Here, we established a novel bioluminescence resonance energy transfer (BRET) assay to dissect and monitor PML/SUMO interactions dynamically in living cells upon addition of therapeutic agents. Using this sensitive and quantitative SUMO BRET assay that distinguishes PML sumoylation from SBD-mediated PML/SUMO non-covalent interactions, we probed the respective roles of covalent and non-covalent PML/SUMO interactions in PML degradation and interaction with RNF4. We found that, although dispensable for As2O3-enhanced PML sumoylation and RNF4 interaction, PML SBD core sequence was required for As2O3- and RNF4-induced PML degradation. As confirmed with a phosphomimetic mutant, phosphorylation of a stretch of serine residues, contained within PML SBD was needed for PML interaction with SUMO-modified protein partners and thus for NB maturation. However, mutation of these serine residues did not impair As2O3- and RNF4-induced PML degradation, contrasting with the known role of these phosphoserine residues for casein kinase 2-promoted PML degradation. Altogether, these data suggest a model whereby sumoylation- and SBD-dependent PML oligomerization within NBs is sufficient for RNF4-mediated PML degradation and does not require the phosphorylation-dependent association of PML with other sumoylated partners. PMID:19380586

  13. Mn(ii) mediated degradation of artemisinin based on Fe3O4@MnSiO3-FA nanospheres for cancer therapy in vivo

    Science.gov (United States)

    Chen, Jian; Zhang, Weijie; Zhang, Min; Guo, Zhen; Wang, Haibao; He, Mengni; Xu, Pengping; Zhou, Jiajia; Liu, Zhenbang; Chen, Qianwang

    2015-07-01

    improving the survival of chemotherapy patients, providing a novel method for clinical tumor therapy. Electronic supplementary information (ESI) available: Iron mediated degradation mechanism for artemisinin, mechanism of alkylation of iron(ii)-heme or iron(ii)/heme dimethylester by artemisinin, mechanism of alkylation of the heme model MnIITPP by artemisinin, schematic illustration of the synthesis of ART-loaded Fe3O4@MnSiO3-FA nanospheres, further characterization such as XRD and EDX patterns, N2 adsorption and desorption isotherm and BJH pore distribution, FT-IR spectra, UV-vis spectra, DLS and parallel test results of flow cytometric detection are given in Fig. S1-S13, Fe2+ or Mn2+ release from Fe3O4@MnSiO3 nanospheres in PBS at different pHs is given in Table S1. See DOI: 10.1039/c5nr02402a

  14. Detoxification of azinophos methyl using gamma radiation mediated advance oxidation process and investigation of degradation products by HPLC and GC-MS

    International Nuclear Information System (INIS)

    Gamma radiolytic degradation of azinophos-methyl was studied in water and methanol separately, using 60Co as a radiation source under varied experimental conditions. Solution of azinophos-methyl was prepared in pure methanol at concentration of 50 μg ml-1, irradiated at gamma dose of 1 to 7 kGy and high performance liquid chromatography (HPLC) coupled with diode array detector was used to monitor the extent of degradation along with numbers of degradation products. At dose of 7 kGy ≥ 99% of azinophos-methyl was degraded. The degradation occurred by interaction of CH3O x and H x radicals generated by the radiolysis of high purity methanol while in water by x OH radical. The degradation in water was increased by 30% than in methanol due the high oxidation potential of x OH while keeping the gamma ray dose constant at 3 kGy. The generated degradation products were identified using GC-MS and their possible transformation pathways are proposed. It is suggested that use of ionization radiations can be an effective and efficient tool for the removal of organophosphate pesticides in waste water.

  15. Epstein-Barr Virus Nuclear Antigen 3C Augments Mdm2-Mediated p53 Ubiquitination and Degradation by Deubiquitinating Mdm2▿

    OpenAIRE

    Saha, Abhik; Murakami, Masanao; Kumar, Pankaj; Bajaj, Bharat; Sims, Karen; Erle S Robertson

    2009-01-01

    Epstein-Barr virus (EBV) nuclear antigen 3C (EBNA3C) is one of the essential latent antigens for primary B-cell transformation. Previous studies established that EBNA3C facilitates degradation of several vital cell cycle regulators, including the retinoblastoma (pRb) and p27KIP proteins, by recruitment of the SCFSkp2 E3 ubiquitin ligase complex. EBNA3C was also shown to be ubiquitinated at its N-terminal residues. Furthermore, EBNA3C can bind to and be degraded in vitro by purified 20S protea...

  16. The novel complement inhibitor human CUB and Sushi multiple domains 1 (CSMD1) protein promotes factor I-mediated degradation of C4b and C3b and inhibits the membrane attack complex assembly.

    Science.gov (United States)

    Escudero-Esparza, Astrid; Kalchishkova, Nikolina; Kurbasic, Emila; Jiang, Wen G; Blom, Anna M

    2013-12-01

    CUB and Sushi multiple domains 1 (CSMD1) is a transmembrane protein containing 15 consecutive complement control protein (CCP) domains, which are characteristic for complement inhibitors. We expressed a membrane-bound fragment of human CSMD1 composed of the 15 C-terminal CCP domains and demonstrated that it inhibits deposition of C3b by the classical pathway on the surface of Chinese hamster ovary cells by 70% at 6% serum and of C9 (component of membrane attack complex) by 90% at 1.25% serum. Furthermore, this fragment of CSMD1 served as a cofactor to factor I-mediated degradation of C3b. In all functional assays performed, well-characterized complement inhibitors were used as positive controls, whereas Coxsackie adenovirus receptor, a protein with no effect on complement, was a negative control. Moreover, attenuation of expression in human T47 breast cancer cells that express endogenous CSMD1 significantly increased C3b deposition on these cells by 45% at 8% serum compared with that for the controls. Furthermore, by expressing a soluble 17-21 CCP fragment of CSMD1, we found that CSMD1 inhibits complement by promoting factor I-mediated C4b/C3b degradation and inhibition of MAC assembly at the level of C7. Our results revealed a novel complement inhibitor for the classical and lectin pathways. PMID:23964079

  17. Interleukin 17A inhibits autophagy through activation of PIK3CA to interrupt the GSK3B-mediated degradation of BCL2 in lung epithelial cells

    OpenAIRE

    Liu, Hong; Mi, Su; Li, Zhe; Hua, Fang; Hu, Zhuo-Wei

    2013-01-01

    We recently found that activation of IL17A signaling promotes the development and progression of acute and chronic pulmonary fibrosis, and that the blockade of IL17A activity attenuates pulmonary fibrosis by promoting the resolution of inflammation and the activation of autophagy. Although the induction of autophagy stimulating the collagen degradation in the fibrotic lung tissue has been identified as a mechanism responsible for the antifibrotic role of targeting IL17A, it remains to be clar...

  18. Mycorrhizal-Mediated Lower Proline Accumulation in Poncirus trifoliata under Water Deficit Derives from the Integration of Inhibition of Proline Synthesis with Increase of Proline Degradation

    OpenAIRE

    Ying-Ning ZOU; Wu, Qiang-Sheng; Huang, Yong-Ming; Qiu-Dan NI; He, Xin-Hua

    2013-01-01

    Proline accumulation was often correlated with drought tolerance of plants infected by arbuscular mycorrhizal fungi (AMF), whereas lower proline in some AM plants including citrus was also found under drought stress and the relevant mechanisms have not been fully elaborated. In this study proline accumulation and activity of key enzymes relative to proline biosynthesis (▵1-pyrroline-5-carboxylate synthetase, P5CS; ornithine-δ-aminotransferase, OAT) and degradation (proline dehydrogenase, ProD...

  19. MMP Mediated Degradation of Type VI Collagen Is Highly Associated with Liver Fibrosis - Identification and Validation of a Novel Biochemical Marker Assay

    DEFF Research Database (Denmark)

    Veidal, Sanne Skovgard; Karsdal, Morten Asser; Vassiliadis, Efstathios; Nawrocki, Arkadiusz; Larsen, Martin Rossel; Quoc, HTN; Hägglund, Per; Luo, Yunyun; Zheng, Qinlong; Vainer, Ben; Leeming, Diana Julie

    2011-01-01

    Background and Aims: During fibrogenesis, in which excessive remodeling of the extracellular matrix occurs, both the quantity of type VI collagen and levels of matrix metalloproteinases, including MMP-2 and MMP-9, increase significantly. Proteolytic degradation of type VI collagen into small...... fragments, so-called neo-epitopes, may be specific biochemical marker of liver fibrosis. The aim of this study was to develop an ELISA detecting a fragment of type VI collagen generated by MMP-2 and MMP-9, and evaluate this assay in two preclinical models of liver fibrosis. Methods: Mass spectrometric...... analysis of cleaved type VI collagen revealed a large number of protease-generated neo-epitopes. A fragment unique to type VI collagen generated by MMP-2 and MMP-9 was selected for ELISA development. The CO6-MMP assay was evaluated in two rat models of liver fibrosis: bile duct ligation (BDL) and carbon...

  20. Defect-mediated of Cu@TiO2 core-shell nanoparticles with oxygen vacancies for photocatalytic degradation 2,4-DCP under visible light irradiation

    Science.gov (United States)

    Wang, Zhen; Zang, Ling; Fan, Xiaoyun; Jia, Hanzhong; Li, Li; Deng, Wenye; Wang, Chuanyi

    2015-12-01

    Cu @TiO2 core-shell nanoparticles with different mass ratios of Cu to TiO2 were facilely synthesized via wet chemical approaches, and were characterized by transmission electron microscopy, scanning electron microscopy, UV-vis diffuse reflection absorption spectroscopy, X-ray photoelectron spectroscopy and electron paramagnetic resonance. The photocatalytic efficiency of Cu@TiO2 nanoparticles was evaluated by degradation of 2,4-dichlorophenol, a typical persistent organic pollutant, under visible light irradiation. The results show that the oxygen vacancy creation obviously enhances the visible-light absorption of TiO2. Meanwhile, the Cu nanoparticle incorporation into the TiO2 can effectively improve charge-separation efficiency of Cu@TiO2 under visible-light irradiation, thereby enhancing the photoactivity.

  1. Phosphodiesterase inhibition mediates matrix metalloproteinase activity and the level of collagen degradation fragments in a liver fibrosis ex vivo rat model

    Directory of Open Access Journals (Sweden)

    Veidal Sanne Skovgård

    2012-12-01

    Full Text Available Abstract Background Accumulation of extracellular matrix (ECM and increased matrix metalloproteinase (MMP activity are hallmarks of liver fibrosis. The aim of the present study was to develop a model of liver fibrosis combining ex vivo tissue culture of livers from CCl4 treated animals with an ELISA detecting a fragment of type III collagen generated in vitro by MMP-9 (C3M, known to be associated with liver fibrosis and to investigate cAMP modulation of MMP activity and liver tissue turnover in this model. Findings In vivo: Rats were treated for 8 weeks with CCl4/Intralipid. Liver slices were cultured for 48 hours. Levels of C3M were determined in the supernatants of slices cultured without treatment, treated with GM6001 (positive control or treated with IBMX (phosphodiesterase inhibitor. Enzymatic activity of MMP-2 and MMP-9 were studied by gelatin zymography. Ex vivo: The levels of serum C3M increased 77% in the CCl4-treated rats at week 8 (p 4-treated animals had highly increased MMP-9, but not MMP-2 activity, compared to slices derived from control animals. Conclusions We have combined an ex vivo model of liver fibrosis with measurement of a biochemical marker of collagen degradation in the condition medium. This technology may be used to evaluate the molecular process leading to structural fibrotic changes, as collagen species are the predominant structural part of fibrosis. These data suggest that modulation of cAMP may play a role in regulation of collagen degradation associated with liver fibrosis.

  2. Mycorrhizal-mediated lower proline accumulation in Poncirus trifoliata under water deficit derives from the integration of inhibition of proline synthesis with increase of proline degradation.

    Directory of Open Access Journals (Sweden)

    Ying-Ning Zou

    Full Text Available Proline accumulation was often correlated with drought tolerance of plants infected by arbuscular mycorrhizal fungi (AMF, whereas lower proline in some AM plants including citrus was also found under drought stress and the relevant mechanisms have not been fully elaborated. In this study proline accumulation and activity of key enzymes relative to proline biosynthesis (▵(1-pyrroline-5-carboxylate synthetase, P5CS; ornithine-δ-aminotransferase, OAT and degradation (proline dehydrogenase, ProDH were determined in trifoliate orange (Poncirus trifoliata, a widely used citrus rootstock inoculated with or without Funneliformis mosseae and under well-watered (WW or water deficit (WD. AMF colonization significantly increased plant height, stem diameter, leaf number, root volume, biomass production of both leaves and roots and leaf relative water content, irrespectively of water status. Water deficit induced more tissue proline accumulation, in company with an increase of P5CS activity, but a decrease of OAT and ProDH activity, no matter whether under AM or no-AM. Compared with no-AM treatment, AM treatment resulted in lower proline concentration and content in leaf, root, and total plant under both WW and WD. The AMF colonization significantly decreased the activity of both P5CS and OAT in leaf, root, and total plant under WW and WD, except for an insignificant difference of root OAT under WD. The AMF inoculation also generally increased tissue ProDH activity under WW and WD. Plant proline content significantly positively correlated with plant P5CS activity, negatively with plant ProDH activity, but not with plant OAT activity. These results suggest that AM plants may suffer less from WD, thereby inducing lower proline accumulation, which derives from the integration of an inhibition of proline synthesis with an enhancement of proline degradation.

  3. c-IAP1 Binds and Processes PCSK9 Protein: Linking the c-IAP1 in a TNF-α Pathway to PCSK9-Mediated LDLR Degradation Pathway

    Directory of Open Access Journals (Sweden)

    David Hornby

    2012-10-01

    Full Text Available Recent genetic studies have shown that PCSK9, one of the key genes in cholesterol metabolism, plays a critical role by controlling the level of low-density lipoprotein receptor. However, how PCSK9 mediates LDLR degradation is still unknown. By combining a shotgun proteomic method and differential analysis of natural occurring mutations of the PCSK9 gene, we found that an E3 ubiquitin ligase c-IAP1 binds and processes PCSK9 protein. One of the ‘gain-of-function’ mutations, S127R, is defective with respect to binding to c-IAP1, and thus has defective autocatalytic activity. Knockdown of c-IAP1 impairs PCSK9 processing and autocatalytic cleavage. In c-IAP1 null mouse embryonic fibroblasts (MEFs, there is a dramatic decrease in secreted mature PCSK9 protein accompanied by a significant increase in LDLR protein levels compared with matched wild-type MEF cells. c-IAP1 also acts as an E3 ligase for ubiquitination of PCSK9. Ubiquitin containing only lysine-27 mediated PCSK9 ubiquitination by c-IAP1. Given K27-linked polyubiquitination promotes lysosomal localization, the finding indicates the c-IAP1 acts on both secretion of PCSK9 and its lysosomal localization. The novel pathway described here will open new avenues for exploring novel disease treatments.

  4. 自带介质血红密孔菌NFZH-1的鉴定及其木质素降解特性%Identification and Lignin Degradation of Pycnoporus sanguineus Strain NFZH-1 with an Endogenous Mediator

    Institute of Scientific and Technical Information of China (English)

    冯年捷; 翟华敏; 王传槐

    2014-01-01

    The process of lignin degradation by white-rot fungi can be intensified by the presence of endogenous mediators. A high-yield laccase-producing fungus with an endogenous mediator is important for the commercial application of laccase. In the present study, we isolated two strains of Pycnoporus sanguineus, namely, NFZH-1 and NFZH-2 from mountain forest region in Nanjing, China, and their laccase production and delignifying characteristics was studied. We also studied these strains in comparison with the best-studied lignin-degrading fungus, Coriolus versicolor. P. sanguineus strain NFZH-1 with an endogenous mediator was identified. Thereafter, NFZH-1 was found to be a high yield laccase-producing strain as determined by the color-reaction and solid-state fermentation. The color zone diameter of NFZH-1 was found to be substantially greater than the mycelia colony one. Moreover, the color zone revealed a dark brown color-reaction using guaiacol as substrate. The laccase activities of P. sanguineus NFZH-1 were found to be 23 600 U/g, while no LiP and MnP were produced in solid-state fermentation. NFZH-1 demonstrated the capability to degrade 56. 7% of Klason lignin and 36. 6% of holocellulose in wheat straw within 30 days of incubation. Our results indicate that P. sanguineus NFZH-1 is a powerful and selective lignin-degrading strain.%菌株自带介质可提高其漆酶降解木质素能力,因此自带介质高产漆酶菌株的筛选、鉴定对漆酶的商业应用将起到促进作用。从南京山林地区分离出两株血红密孔菌NFZH-1和NFZH-2,并以杂色云芝为对照,研究了两株血红密孔菌发酵产漆酶和木质素降解特性。首先通过形态学特性鉴定了NFZH-1为自带介质血红密孔菌。其次以愈创木酚为反应底物,平板接种菌株,培养5天,NFZH-1颜色圈较菌丝圈大,且颜色最深;经10天固态发酵,NFZH-1所产漆酶酶活高达23600 U/g,且未检测出木质素过氧化物酶( Li

  5. The cAMP signaling system inhibits the repair of γ-ray-induced DNA damage by promoting Epac1-mediated proteasomal degradation of XRCC1 protein in human lung cancer cells

    International Nuclear Information System (INIS)

    Highlights: ► cAMP signaling system inhibits repair of γ-ray-induced DNA damage. ► cAMP signaling system inhibits DNA damage repair by decreasing XRCC1 expression. ► cAMP signaling system decreases XRCC1 expression by promoting its proteasomal degradation. ► The promotion of XRCC1 degradation by cAMP signaling system is mediated by Epac1. -- Abstract: Cyclic AMP is involved in the regulation of metabolism, gene expression, cellular growth and proliferation. Recently, the cAMP signaling system was found to modulate DNA-damaging agent-induced apoptosis by regulating the expression of Bcl-2 family proteins and inhibitors of apoptosis. Thus, we hypothesized that the cAMP signaling may modulate DNA repair activity, and we investigated the effects of the cAMP signaling system on γ-ray-induced DNA damage repair in lung cancer cells. Transient expression of a constitutively active mutant of stimulatory G protein (GαsQL) or treatment with forskolin, an adenylyl cyclase activator, augmented radiation-induced DNA damage and inhibited repair of the damage in H1299 lung cancer cells. Expression of GαsQL or treatment with forskolin or isoproterenol inhibited the radiation-induced expression of the XRCC1 protein, and exogenous expression of XRCC1 abolished the DNA repair-inhibiting effect of forskolin. Forskolin treatment promoted the ubiquitin and proteasome-dependent degradation of the XRCC1 protein, resulting in a significant decrease in the half-life of the protein after γ-ray irradiation. The effect of forskolin on XRCC1 expression was not inhibited by PKA inhibitor, but 8-pCPT-2′-O-Me-cAMP, an Epac-selective cAMP analog, increased ubiquitination of XRCC1 protein and decreased XRCC1 expression. Knockdown of Epac1 abolished the effect of 8-pCPT-2′-O-Me-cAMP and restored XRCC1 protein level following γ-ray irradiation. From these results, we conclude that the cAMP signaling system inhibits the repair of γ-ray-induced DNA damage by promoting the ubiquitin

  6. Seed-mediated synthesis and the photo-degradation activity of ZnO-graphene hybrids excluding the influence of dye adsorption

    Science.gov (United States)

    Fu, Dongying; Han, Gaoyi; Yang, Feifei; Zhang, Tianwen; Chang, Yunzhen; Liu, Feifei

    2013-10-01

    The nano-sized ZnO-graphene hybrid has been prepared through combining the facile sol-gel process and hydrothermal method by using Zn(NO3)2·6H2O and hexamethylenetetramine (HMT) as growing reactants in the presence of ZnO-graphene oxide (ZnO-GO) seeds. The obtained products have been characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, Raman spectroscopy and UV-vis absorption spectroscopy. The results show that the GO has been converted to reduced-graphene oxide during the hydrothermal process due to the released reductant from HMT. The photo-degradation of methylene blue in the presence of ZnO-graphene (excluding the influence of the dye adsorption on the catalyst) has also been investigated in detail. It is found that the preparation conditions have significant effects on photo-catalytic properties of the composites, and that ZnO-graphene prepared in the optimal conditions exhibits the optimum activity. This facile and low-cost method will make the composite a perfect candidate in applications of photo-catalysis and other areas.

  7. Seed-mediated synthesis and the photo-degradation activity of ZnO–graphene hybrids excluding the influence of dye adsorption

    Energy Technology Data Exchange (ETDEWEB)

    Fu, Dongying; Han, Gaoyi, E-mail: han_gaoyis@sxu.edu.cn; Yang, Feifei; Zhang, Tianwen; Chang, Yunzhen; Liu, Feifei

    2013-10-15

    The nano-sized ZnO–graphene hybrid has been prepared through combining the facile sol–gel process and hydrothermal method by using Zn(NO{sub 3}){sub 2}·6H{sub 2}O and hexamethylenetetramine (HMT) as growing reactants in the presence of ZnO–graphene oxide (ZnO–GO) seeds. The obtained products have been characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, Raman spectroscopy and UV–vis absorption spectroscopy. The results show that the GO has been converted to reduced-graphene oxide during the hydrothermal process due to the released reductant from HMT. The photo-degradation of methylene blue in the presence of ZnO–graphene (excluding the influence of the dye adsorption on the catalyst) has also been investigated in detail. It is found that the preparation conditions have significant effects on photo-catalytic properties of the composites, and that ZnO–graphene prepared in the optimal conditions exhibits the optimum activity. This facile and low-cost method will make the composite a perfect candidate in applications of photo-catalysis and other areas.

  8. Vpx mediated degradation of SAMHD1 has only a very limited effect on lentiviral transduction rate in ex vivo cultured HSPCs.

    Science.gov (United States)

    Li, Duo; Schlaepfer, Erika; Audigé, Annette; Rochat, Mary-Aude; Ivic, Sandra; Knowlton, Caitlin N; Kim, Baek; Keppler, Oliver T; Speck, Roberto F

    2015-09-01

    Understanding how to achieve efficient transduction of hematopoietic stem and progenitor cells (HSPCs), while preserving their long-term ability to self-reproduce, is key for applying lentiviral-based gene engineering methods. SAMHD1 is an HIV-1 restriction factor in myeloid and resting CD4+ T cells that interferes with reverse transcription by decreasing the nucleotide pools or by its RNase activity. Here we show that SAMHD1 is expressed at high levels in HSPCs cultured in a medium enriched with cytokines. Thus, we hypothesized that degrading SAMHD1 in HSPCs would result in more efficient lentiviral transduction rates. We used viral like particles (VLPs) containing Vpx, shRNA against SAMHD1, or provided an excess of dNTPs or dNs to study this question. Regardless of the method applied, we saw no increase in the lentiviral transduction rate. The result was different when we used viruses (HR-GFP-Vpx+) which carry Vpx and encode GFP. These viruses allow assessment of the effects of Vpx specifically in the transduced cells. Using HR-GFP-Vpx+ viruses, we observed a modest but significant increase in the transduction efficiency. These data suggest that SAMHD1 has some limited efficacy in blocking reverse transcription but the major barrier for efficient lentiviral transduction occurs before reverse transcription. PMID:26207584

  9. Seed-mediated synthesis and the photo-degradation activity of ZnO–graphene hybrids excluding the influence of dye adsorption

    International Nuclear Information System (INIS)

    The nano-sized ZnO–graphene hybrid has been prepared through combining the facile sol–gel process and hydrothermal method by using Zn(NO3)2·6H2O and hexamethylenetetramine (HMT) as growing reactants in the presence of ZnO–graphene oxide (ZnO–GO) seeds. The obtained products have been characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, Raman spectroscopy and UV–vis absorption spectroscopy. The results show that the GO has been converted to reduced-graphene oxide during the hydrothermal process due to the released reductant from HMT. The photo-degradation of methylene blue in the presence of ZnO–graphene (excluding the influence of the dye adsorption on the catalyst) has also been investigated in detail. It is found that the preparation conditions have significant effects on photo-catalytic properties of the composites, and that ZnO–graphene prepared in the optimal conditions exhibits the optimum activity. This facile and low-cost method will make the composite a perfect candidate in applications of photo-catalysis and other areas.

  10. SKI2 mediates degradation of RISC 5'-cleavage fragments and prevents secondary siRNA production from miRNA targets in Arabidopsis

    DEFF Research Database (Denmark)

    Branscheid, Anja; Marchais, Antonin; Schott, Gregory; Lange, Heike; Gagliardi, Dominique; Andersen, Stig Uggerhøj; Voinnet, Olivier; Brodersen, Peter

    2015-01-01

    Small regulatory RNAs are fundamental in eukaryotic and prokaryotic gene regulation. In plants, an important element of post-transcriptional control is effected by 20-24 nt microRNAs (miRNAs) and short interfering RNAs (siRNAs) bound to the ARGONAUTE1 (AGO1) protein in an RNA induced silencing...... complex (RISC). AGO1 may cleave target mRNAs with small RNA complementarity, but the fate of the resulting cleavage fragments remains incompletely understood. Here, we show that SKI2, SKI3 and SKI8, subunits of a cytoplasmic cofactor of the RNA exosome, are required for degradation of RISC 5', but not 3......'-cleavage fragments in Arabidopsis. In the absence of SKI2 activity, many miRNA targets produce siRNAs via the RNA-dependent RNA polymerase 6 (RDR6) pathway. These siRNAs are low-abundant, and map close to the cleavage site. In most cases, siRNAs were produced 5' to the cleavage site, but several examples...

  11. p38 MAPK-induced MDM2 degradation confers paclitaxel resistance through p53-mediated regulation of EGFR in human lung cancer cells

    Science.gov (United States)

    Park, Shin-Hyung; Seong, Myeong-A; Lee, Ho-Young

    2016-01-01

    Paclitaxel (PTX) is a chemotherapeutic agent that is used to treat a variety of cancers, including non-small cell lung cancer (NSCLC). However, the emergence of drug resistance limits the utility of PTX. This study determined the signaling pathway that contributes to PTX resistance. We first established PTX resistant cell lines (H460/R and 226B/R) using a dose-escalating maintenance of PTX. We found that p38 MAPK and epidermal growth factor receptor (EGFR) were constitutively activated in these cell lines. The inhibition of p38 MAPK activity by SB203580 treatment or the transfection of dominant-negative p38 MAPK sensitized both cell lines to PTX treatment. Erlotinib, an EGFR inhibitor, also increased PTX-induced apoptosis in PTX resistant cells, which suggests a role for p38 MAPK and EGFR in the development of PTX resistance. We demonstrated that p38 MAPK enhanced EGFR expression via the induction of the rapid degradation of mouse double-minute 2 homolog (MDM2) and the consequent stabilization of p53, a transcription factor of EGFR. These results suggest for the first time that the p38 MAPK/p53/EGFR axis is crucial for the facilitation of PTX resistance in NSCLCs. We also propose a mechanism for the role of the tumor-suppressor p53 in drug resistance. These results provide a foundation for the future development of potential therapeutic strategies to regulate the p38 MAPK/p53/EGFR pathway for the treatment of lung cancer patients with PTX resistance. PMID:26799187

  12. C/EBP β Mediates Endoplasmic Reticulum Stress Regulated Inflammatory Response and Extracellular Matrix Degradation in LPS-Stimulated Human Periodontal Ligament Cells

    Science.gov (United States)

    Bai, Yudi; Wei, Yi; Wu, Lian; Wei, Jianhua; Wang, Xiaojing; Bai, Yuxiang

    2016-01-01

    Periodontitis is an oral inflammatory disease that not only affects the integrity of local tooth-supporting tissues but also impacts systemic health. A compositional shift in oral microbiota has been considered as the main cause of periodontitis; however, the potential mechanism has not been fully defined. Herein, we investigated the role of CCAAT/enhancer-binding protein β (C/EBP β), a member of the C/EBP family of transcription factors, in human periodontal ligament cells (hPDLCs) exposed to Porphyromonas gingivalis (P. gingivalis) lipopolysaccharide (LPS). RT-PCR and Western blotting analysis showed that the expression of C/EBP β was significantly increased in hPDLCs stimulated with LPS stimuli. Overexpression of C/EBP β by the recombinant adenoviral vector pAd/C/EBP β markedly increased the expression of the pro-inflammatory cytokines IL-6 and IL-8, and matrix metalloproteinases (MMP)-8 and -9 in hPDLCs in response to LPS. Furthermore, the activation of endoplasmic reticulum (ER) stress was confirmed in LPS-stimulated hPDLCs by measuring the expression of the ER stress marker molecules protein kinase-like ER kinase (PERK), eIF2α, GRP78/Bip, and C/EBP homologous protein (CHOP). The ER stress inhibitor salubrinal repressed, but inducer tunicamycin enhanced, the production of IL-6, IL-8, MMP-8, and MMP-9 in hPDLCs. Additionally, ER stress inducer tunicamycin significantly increased the expression level of C/EBP β in hPDLCs. Blocking of C/EBP β by siRNA resulted in a significant decrease in the secretion of IL-6 and IL-8 and expression of MMP-8 and MMP-9 induced by tunicamycin treatment in hPDLCs. Taken together, ER stress appears to play a regulatory role in the inflammatory response and extracellular matrix (ECM) degradation in hPDLCs in response to LPS stimuli by activating C/EBP β expression. This enhances our understanding of human periodontitis pathology. PMID:27011164

  13. Polysaccharide Degradation

    Science.gov (United States)

    Stone, Bruce A.; Svensson, Birte; Collins, Michelle E.; Rastall, Robert A.

    An overview of current and potential enzymes used to degrade polysaccharides is presented. Such depolymerases are comprised of glycoside hydrolases, glycosyl transferases, phosphorylases and lyases, and their classification, active sites and action patterns are discussed. Additionally, the mechanisms that these enzymes use to cleave glycosidic linkages is reviewed as are inhibitors of depolymerase activity; reagents which react with amino acid residues, glycoside derivatives, transition state inhibitors and proteinaceous inhibitors. The characterization of various enzymes of microbial, animal or plant origin has led to their widespread use in the production of important oligosaccharides which can be incorporated into food stuffs. Sources of polysaccharides of particular interest in this chapter are those from plants and include inulin, dextran, xylan and pectin, as their hydrolysis products are purported to be functional foods in the context of gastrointestinal health. An alternative use of degraded polysaccharides is in the treatment of disease. The possibility exists to treat bacterial exopolysaccharide with lyases from bacteriophage to produce oligosaccharides exhibiting bioactive sequences. Although this area is currently in its infancy the knowledge is available to investigate further.

  14. Escape of HIV-1-infected dendritic cells from TRAIL-mediated NK cell cytotoxicity during NK-DC cross-talk--a pivotal role of HMGB1.

    Directory of Open Access Journals (Sweden)

    Marie-Thérèse Melki

    2010-04-01

    Full Text Available Early stages of Human Immunodeficiency Virus-1 (HIV-1 infection are associated with local recruitment and activation of important effectors of innate immunity, i.e. natural killer (NK cells and dendritic cells (DCs. Immature DCs (iDCs capture HIV-1 through specific receptors and can disseminate the infection to lymphoid tissues following their migration, which is associated to a maturation process. This process is dependent on NK cells, whose role is to keep in check the quality and the quantity of DCs undergoing maturation. If DC maturation is inappropriate, NK cells will kill them ("editing process" at sites of tissue inflammation, thus optimizing the adaptive immunity. In the context of a viral infection, NK-dependent killing of infected-DCs is a crucial event required for early elimination of infected target cells. Here, we report that NK-mediated editing of iDCs is impaired if DCs are infected with HIV-1. We first addressed the question of the mechanisms involved in iDC editing, and we show that cognate NK-iDC interaction triggers apoptosis via the TNF-related apoptosis-inducing ligand (TRAIL-Death Receptor 4 (DR4 pathway and not via the perforin pathway. Nevertheless, once infected with HIV-1, DC(HIV become resistant to NK-induced TRAIL-mediated apoptosis. This resistance occurs despite normal amounts of TRAIL released by NK cells and comparable DR4 expression on DC(HIV. The escape of DC(HIV from NK killing is due to the upregulation of two anti-apoptotic molecules, the cellular-Flice like inhibitory protein (c-FLIP and the cellular inhibitor of apoptosis 2 (c-IAP2, induced by NK-DC(HIV cognate interaction. High-mobility group box 1 (HMGB1, an alarmin and a key mediator of NK-DC cross-talk, was found to play a pivotal role in NK-dependent upregulation of c-FLIP and c-IAP2 in DC(HIV. Finally, we demonstrate that restoration of DC(HIV susceptibility to NK-induced TRAIL killing can be obtained either by silencing c-FLIP and c-IAP2 by specific

  15. Roles of protein ubiquitination and degradation kinetics in biological oscillations.

    Directory of Open Access Journals (Sweden)

    Lida Xu

    Full Text Available Protein ubiquitination and degradation play important roles in many biological functions and are associated with many human diseases. It is well known that for biochemical oscillations to occur, proper degradation rates of the participating proteins are needed. In most mathematical models of biochemical reactions, linear degradation kinetics has been used. However, the degradation kinetics in real systems may be nonlinear, and how nonlinear degradation kinetics affects biological oscillations are not well understood. In this study, we first develop a biochemical reaction model of protein ubiquitination and degradation and calculate the degradation rate against the concentration of the free substrate. We show that the protein degradation kinetics mainly follows the Michaelis-Menten formulation with a time delay caused by ubiquitination and deubiquitination. We then study analytically how the Michaelis-Menten degradation kinetics affects the instabilities that lead to oscillations using three generic oscillation models: 1 a positive feedback mediated oscillator; 2 a positive-plus-negative feedback mediated oscillator; and 3 a negative feedback mediated oscillator. In all three cases, nonlinear degradation kinetics promotes oscillations, especially for the negative feedback mediated oscillator, resulting in much larger oscillation amplitudes and slower frequencies than those observed with linear kinetics. However, the time delay due to protein ubiquitination and deubiquitination generally suppresses oscillations, reducing the amplitude and increasing the frequency of the oscillations. These theoretical analyses provide mechanistic insights into the effects of specific proteins in the ubiquitination-proteasome system on biological oscillations.

  16. Mediation Analysis

    OpenAIRE

    David P. MacKinnon; Fairchild, Amanda J.; Fritz, Matthew S.

    2007-01-01

    Mediating variables are prominent in psychological theory and research. A mediating variable transmits the effect of an independent variable on a dependent variable. Differences between mediating variables and confounders, moderators, and covariates are outlined. Statistical methods to assess mediation and modern comprehensive approaches are described. Future directions for mediation analysis are discussed.

  17. Mechanistic study of a diazo dye degradation by Soybean Peroxidase

    OpenAIRE

    Kalsoom, Umme; Ashraf, Syed Salman; Meetani, Mohammed A; Rauf, Muhammad A; Bhatti, Haq Nawaz

    2013-01-01

    Background Enzyme based remediation of wastewater is emerging as a novel, efficient and environmentally-friendlier approach. However, studies showing detailed mechanisms of enzyme mediated degradation of organic pollutants are not widely published. Results The present report describes a detailed study on the use of Soybean Peroxidase to efficiently degrade Trypan Blue, a diazo dye. In addition to examining various parameters that can affect the dye degradation ability of the enzyme, such as e...

  18. North American Soil Degradation: Processes, Practices, and Mitigating Strategies

    OpenAIRE

    Baumhardt, R.L.; Stewart, B.A.; U. M. Sainju

    2015-01-01

    Soil can be degraded by several natural or human-mediated processes, including wind, water, or tillage erosion, and formation of undesirable physical, chemical, or biological properties due to industrialization or use of inappropriate farming practices. Soil degradation occurs whenever these processes supersede natural soil regeneration and, generally, reflects unsustainable resource management that is global in scope and compromises world food security. In North America, soil degradation pre...

  19. Role of SUMO in RNF4-mediated Promyelocytic Leukemia Protein (PML) Degradation: Sumoylation of pml and phospho-switch control of its sumo binding domain dissected in living cells*

    OpenAIRE

    Percherancier, Yann; Germain-Desprez, Delphine; Galisson, Frédéric; Mascle, Xavier H.; Dianoux, Laurent; Estephan, Patricia; Chelbi-Alix, Mounira K.; Aubry, Muriel

    2009-01-01

    Promyelocytic leukemia protein (PML) is a tumor suppressor acting as the organizer of subnuclear structures called PML nuclear bodies (NBs). Both covalent modification of PML by the small ubiquitin-like modifier (SUMO) and non-covalent binding of SUMO to the PML SUMO binding domain (SBD) are necessary for PML NB formation and maturation. PML sumoylation and proteasome-dependent degradation induced by the E3 ubiquitin ligase, RNF4, are enhanced by the acute promyelocytic leukemia therapeutic a...

  20. Addition of Aromatic Substrates Restores Trichloroethylene Degradation Activity in Pseudomonas putida F1

    OpenAIRE

    Morono, Yuki; Unno, Hajime; TANJI, Yasunori; Hori, Katsutoshi

    2004-01-01

    The rate of trichloroethylene (TCE) degradation by toluene dioxygenase (TDO) in resting cells of Pseudomonas putida F1 gradually decreased and eventually stopped within 1.5 h, as in previous reports. However, the subsequent addition of toluene, which is the principal substrate of TDO, resulted in its immediate degradation without a lag phase. After the consumption of toluene, degradation of TCE restarted at a rate similar to its initial degradation, suggesting that this degradation was mediat...

  1. Interferon-β-induced activation of c-Jun NH2-terminal kinase mediates apoptosis through up-regulation of CD95 in CH31 B lymphoma cells

    International Nuclear Information System (INIS)

    Type I interferon (IFN)-induced antitumor action is due in part to apoptosis, but the molecular mechanisms underlying IFN-induced apoptosis remain largely unresolved. In the present study, we demonstrate that IFN-β induced apoptosis and the loss of mitochondrial membrane potential (ΔΨm) in the murine CH31 B lymphoma cell line, and this was accompanied by the up-regulation of CD95, but not CD95-ligand (CD95-L), tumor necrosis factor (TNF), or TNF-related apoptosis-inducing ligand (TRAIL). Pretreatment with anti-CD95-L mAb partially prevented the IFN-β-induced loss of ΔΨm, suggesting that the interaction of IFN-β-up-regulated CD95 with CD95-L plays a crucial role in the induction of fratricide. IFN-β induced a sustained activation of c-Jun NH2-terminal kinase 1 (JNK1), but not extracellular signal-regulated kinases (ERKs). The IFN-β-induced apoptosis and loss of ΔΨm were substantially compromised in cells overexpressing a dominant-negative form of JNK1 (dnJNK1), and it was slightly enhanced in cells carrying a constitutively active JNK construct, MKK7-JNK1 fusion protein. The IFN-β-induced up-regulation of CD95 together with caspase-8 activation was also abrogated in the dnJNK1 cells while it was further enhanced in the MKK7-JNK1 cells. The levels of cellular FLIP (c-FLIP), competitively interacting with caspase-8, were down-regulated by stimulation with IFN-β but were reversed by the proteasome inhibitor lactacystin. Collectively, the IFN-β-induced sustained activation of JNK mediates apoptosis, at least in part, through up-regulation of CD95 protein in combination with down-regulation of c-FLIP protein

  2. DNA degradation and Apoptosis : DNA degradation

    OpenAIRE

    Torriglia, Alicia; Padron, Laura

    2005-01-01

    Apoptosis, is a form of programmed cell death essential for the development and maintenance of multicellular organisms. DNA degradation is one of the hallmarks of apoptosis. The central component of the apoptotic machinery is a proteolytic system involving caspases and non-caspases proteases. CAD, a caspase-activated DNase, is the endonuclease responsible for DNA degradation during caspase-dependent apoptosis. The relationship between non-caspase proteases and endonucleases is less clear and ...

  3. In vitro study on the degradation of lithium-doped hydroxyapatite for bone tissue engineering scaffold.

    Science.gov (United States)

    Wang, Yaping; Yang, Xu; Gu, Zhipeng; Qin, Huanhuan; Li, Li; Liu, Jingwang; Yu, Xixun

    2016-09-01

    Li-doped hydroxyapatite (LiHA) which is prepared through introducing low dose of Li into hydroxyapatite (HA) has been increasingly studied as a bone tissue-engineered scaffold. The degradation properties play a crucial role in the success of long-term implantation of a bone tissue-engineered construct. Herein, the in vitro degradation behaviors of LiHA scaffolds via two approaches were investigated in this study: solution-mediated degradation and osteoblast-mediated degradation. In solution-mediated degradation, after being immersed in simulated body fluid (SBF) for some time, some characteristics of these scaffolds (such as release of ionized lithium and phosphate, pH change, mechanical properties, cytocompatibility and SEM surface characterization) were systematically tested. A similar procedure was also employed to research the degradation behaviors of LiHA scaffolds in osteoblast-mediated degradation. The results suggested that the degradation in SBF and degradation in culture medium with cell existed distinguishing mechanisms. LiHA scaffolds were degraded via a hydrolytic mechanism when they were soaked in SBF. Upon degradation, an apatite precipitation (layer) was formed on the surfaces of scaffolds. While a biological mechanism was presented for the degradation of scaffolds in cell-mediated degradation. Compared with pure HA, LiHA scaffolds had a better effect on the growth of osteoblast cells, meanwhile, the release amount of PO4(3-) in a degradation medium indicated that osteoblasts could accelerate the degradation of LiHA due to the more physiological activities of osteoblast. According to the results from compressive strength test, doping Li into HA could enhance the strength of HA. Moreover, the results from MTT assay and SEM observation showed that the degradation products of LiHA scaffolds were beneficial to the proliferation of osteoblasts. The results of this research can provide the theoretical basis for the clinical application of LiHA scaffolds

  4. Valve actuator motor degradation

    International Nuclear Information System (INIS)

    Valve actuator motor degradation and failure has been a significant, but little studied, problem in the nuclear industry. This study provides a discussion of the primary failure mode --thermal degradation-- and reviews the basis for the solution to thermal degradation -- thermal protection. The study also provides reviews of various industry data bases, discusses effects of other failure modes such as corrosion, and provides a review of other considerations the user should entertain when assessing thermal protection

  5. INTERMITTENT DEGRADATION AND SCHIZOTYPY

    OpenAIRE

    Roché, Matthew W.; Silverstein, Steven M.; Lenzenweger, Mark F.

    2015-01-01

    Intermittent degradation refers to transient detrimental disruptions in task performance. This phenomenon has been repeatedly observed in the performance data of patients with schizophrenia. Whether intermittent degradation is a feature of the liability for schizophrenia (i.e., schizotypy) is an open question. Further, the specificity of intermittent degradation to schizotypy has yet to be investigated. To address these questions, 92 undergraduate participants completed a battery of self-repo...

  6. The Proteasome Inhibitor Bortezomib Sensitizes AML with Myelomonocytic Differentiation to TRAIL Mediated Apoptosis

    International Nuclear Information System (INIS)

    Acute myeloid leukemia (AML) is an aggressive stem cell malignancy that is difficult to treat. There are limitations to the current treatment regimes especially after disease relapse, and therefore new therapeutic agents are urgently required which can overcome drug resistance whilst avoiding unnecessary toxicity. Among newer targeted agents, both tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) and proteasome inhibitors show particular promise. In this report we show that a combination of the proteasome inhibitor bortezomib and TRAIL is effective against AML cell lines, in particular, AML cell lines displaying myelomonocytic/monocytic phenotype (M4/M5 AML based on FAB classification), which account for 20-30% of AML cases. We show that the underlying mechanism of sensitization is at least in part due to bortezomib mediated downregulation of c-FLIP and XIAP, which is likely to be regulated by NF-κB. Blockage of NF-κB activation with BMS-345541 equally sensitized myelomonocytic AML cell lines and primary AML blasts to TRAIL

  7. The Proteasome Inhibitor Bortezomib Sensitizes AML with Myelomonocytic Differentiation to TRAIL Mediated Apoptosis

    Energy Technology Data Exchange (ETDEWEB)

    Dijk, Marianne van; Murphy, Eoin [Apoptosis Research Center, National University of Ireland, University Road, Galway (Ireland); School of Natural Sciences, National University of Ireland, University Road, Galway (Ireland); Morrell, Ruth [Apoptosis Research Center, National University of Ireland, University Road, Galway (Ireland); School of Natural Sciences, National University of Ireland, University Road, Galway (Ireland); School of Medicine, National University of Ireland, University Road, Galway (Ireland); Knapper, Steven [Department of Haematology, School of Medicine, Cardiff University, Heath Park, CF14 4XN Cardiff (United Kingdom); O' Dwyer, Michael [Apoptosis Research Center, National University of Ireland, University Road, Galway (Ireland); School of Medicine, National University of Ireland, University Road, Galway (Ireland); Samali, Afshin; Szegezdi, Eva, E-mail: eva.szegezdi@nuigalway.ie [Apoptosis Research Center, National University of Ireland, University Road, Galway (Ireland); School of Natural Sciences, National University of Ireland, University Road, Galway (Ireland)

    2011-03-15

    Acute myeloid leukemia (AML) is an aggressive stem cell malignancy that is difficult to treat. There are limitations to the current treatment regimes especially after disease relapse, and therefore new therapeutic agents are urgently required which can overcome drug resistance whilst avoiding unnecessary toxicity. Among newer targeted agents, both tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) and proteasome inhibitors show particular promise. In this report we show that a combination of the proteasome inhibitor bortezomib and TRAIL is effective against AML cell lines, in particular, AML cell lines displaying myelomonocytic/monocytic phenotype (M4/M5 AML based on FAB classification), which account for 20-30% of AML cases. We show that the underlying mechanism of sensitization is at least in part due to bortezomib mediated downregulation of c-FLIP and XIAP, which is likely to be regulated by NF-κB. Blockage of NF-κB activation with BMS-345541 equally sensitized myelomonocytic AML cell lines and primary AML blasts to TRAIL.

  8. Transcription-Coupled Replacement of Histones: Degradation or Recycling?

    Institute of Scientific and Technical Information of China (English)

    Yu-Shan Chen; Xiao-Bo Qiu

    2012-01-01

    Histone modifications are proposed to constitute a “histone code” for epigenetic regulation of gene expression.However,recent studies demonstrate that histones have to be disassembled from chromatin during transcription.Recent evidence,though not conclusive,suggests that histones might be degradable after being removed from chromatin during transcription.Degradation of overexpressed excessive histones,instead of native histones,has been shown to be dependent on proteasomes and ubiquitination.Since the 26S proteasome usually recognizes polyubiquitinated substrates,it is critical to demonstrate whether degradation of histones is mediated by polyubiquitination.Unexpectedly,there is almost no evidence that any ubiquitin ligase can promote polyubiquitination-dependent degradation of constitutive histones.Meanwhile,acetylation and phosphorylation are also associated with histone degradation.This review attempts to summarize the current knowledge on the transcription-coupled degradation of histones and its regulation by posttranslational protein modifications.

  9. Pharmacological inhibition of ABCA1 degradation increases HDL biogenesis and exhibits antiatherogenesis[S

    OpenAIRE

    Arakawa, Reijiro; Tsujita, Maki; Iwamoto, Noriyuki; Ito-Ohsumi, Chisato; Lu, Rui; Wu, Chen-Ai; Shimizu, Kenji; Aotsuka, Tomoji; Kanazawa, Hashime; Abe-Dohmae, Sumiko; Yokoyama, Shinji

    2009-01-01

    Expression of ABCA1 is regulated by transcription of the gene and calpain-mediated proteolytic degradation, and inhibition ABCA1 degradation results in increased ABCA1 and HDL biogenesis in vitro. We examined whether this approach could be a potential antiatherogenic treatment. Although probucol inhibits both the activity and degradation of ABCA1, its oxidized products, spiroquinone and diphenoquinone, reduce degradation of ABCA1 without inhibiting its activity or altering transcription of th...

  10. Degradations and Rearrangement Reactions

    Science.gov (United States)

    Zhang, Jianbo

    This section deals with recent reports concerning degradation and rearrangement reactions of free sugars as well as some glycosides. The transformations are classified in chemical and enzymatic ways. In addition, the Maillard reaction will be discussed as an example of degradation and rearrangement transformation and its application in current research in the fields of chemistry and biology.

  11. Rate of NDF degradation

    DEFF Research Database (Denmark)

    Weisbjerg, Martin Riis; Koukolová, V; Lund, Peter

    2007-01-01

    Degradation profiles for NDF were estimated for 83 samples of grass/grass-clover, 27 samples of cereal whole crop and 14 samples of maize whole crop.......Degradation profiles for NDF were estimated for 83 samples of grass/grass-clover, 27 samples of cereal whole crop and 14 samples of maize whole crop....

  12. Complex Mediation

    DEFF Research Database (Denmark)

    Bødker, Susanne; Andersen, Peter Bøgh

    2005-01-01

    This article has its starting point in a large number of empirical findings regarding computer-mediated work. These empirical findings have challenged our understanding of the role of mediation in such work; on the one hand as an aspect of communication and cooperation at work and on the other ha...

  13. Specialized Mediation.

    Science.gov (United States)

    Hammond, Carol; And Others

    1992-01-01

    Six articles discuss librarians as mediators in special circumstances. Highlights include the reference librarian and the information paraprofessional; effective reference mediation for nontraditional public library users, including mentally impaired patrons and illiterate adults; the academic librarian's role in the education process; and…

  14. Silk structure and degradation.

    Science.gov (United States)

    Liu, Bin; Song, Yu-wei; Jin, Li; Wang, Zhi-jian; Pu, De-yong; Lin, Shao-qiang; Zhou, Chan; You, Hua-jian; Ma, Yan; Li, Jin-min; Yang, Li; Sung, K L Paul; Zhang, Yao-guang

    2015-07-01

    To investigate the structure of silk and its degradation properties, we have monitored the structure of silk using scanning electron microscopy and frozen sections. Raw silk and degummed raw silk were immersed in four types of degradation solutions for 156 d to observe their degradation properties. The subcutaneous implants in rats were removed after 7, 14, 56, 84, 129, and 145 d for frozen sectioning and subsequent staining with hematoxylin and eosin (H.E.), DAPI, Beta-actin and Collagen I immunofluorescence staining. The in vitro weight loss ratio of raw silk and degummed raw silk in water, PBS, DMEM and DMEM containing 10% FBS (F-DMEM) were, respectively, 14%/11%, 12.5%/12.9%, 11.1%/14.3%, 8.8%/11.6%. Silk began to degrade after 7 d subcutaneous implantation and after 145 d non-degraded silk was still observed. These findings suggest the immunogenicity of fibroin and sericin had no essential difference. In the process of in vitro degradation of silk, the role of the enzyme is not significant. The in vivo degradation of silk is related to phagocytotic activity and fibroblasts may be involved in this process to secrete collagen. This study also shows the developing process of cocoons and raw silk. PMID:25982316

  15. SPECIFIC DEGRADATION OF WATERSHEDS

    Institute of Scientific and Technical Information of China (English)

    Boubacar KANE; Pierre Y.JULIEN

    2007-01-01

    An extensive database of reservoir sedimentation surveys throughout continental United States is compiled and analyzed to determine specific degradation SD relationships as function of mean annual rainfall R, drainage area A, and watershed slope S. The database contains 1463 field measurements and specific degradation relationships are defined as function of A, R and S. Weak trends and significant variability in the data are noticeable. Specific degradation measurements are log normally distributed with respect to R, A, and S and 95% confidence intervals are determined accordingly. The accuracy of the predictions does not significantly increase as more independent variables are added to the regression analyses.

  16. IL-1β enhances cell adhesion to degraded fibronectin

    OpenAIRE

    Rajshankar, Dhaarmini; Downey, Gregory P.; McCulloch, Christopher A.

    2012-01-01

    IL-1β is a prominent proinflammatory cytokine that mediates degradation of extracellular matrix proteins through increased expression of matrix metalloproteinases, which involves a signaling pathway in adherent cells that is restricted by focal adhesions. Currently, the mechanism by which IL-1β affects cell adhesion to matrix proteins is not defined, and it is not known whether degraded matrix proteins affect IL-1β signaling. We examined adhesion-related IL-1β signaling in fibroblasts attachi...

  17. Purex diluent degradation

    International Nuclear Information System (INIS)

    The chemical degradation of normal paraffin hydrocarbon (NPH) diluents both in the pure state and mixed with 30% tributyl phosphate (TBP) was investigated in a series of experiments. The results show that degradation of NPH in the TBP-NPH-HNO3 system is consistent with the active chemical agent being a radical-like nitrogen dioxide (NO2) molecule, not HNO3 as such. Spectrophotometric, gas chromatographic, mass spectrographic, and titrimetric methods were used to identify the degradation products, which included alkane nitro and nitrate compounds, alcohols, unsaturated alcohols, nitro alcohols, nitro alkenes, ketones, and carboxylic acids. The degradation rate was found to increase with increases in the HNO3 concentration and the temperature. The rate was decreased by argon sparging to remove NO2 and by the addition of butanol, which probably acts as a NO2 scavenger. 13 references, 11 figures

  18. Conceptualizing Forest Degradation.

    Science.gov (United States)

    Ghazoul, Jaboury; Burivalova, Zuzana; Garcia-Ulloa, John; King, Lisa A

    2015-10-01

    Forest degradation is a global environmental issue, but its definition is problematic. Difficulties include choosing appropriate reference states, timescales, thresholds, and forest values. We dispense with many such ambiguities by interpreting forest degradation through the frame of ecological resilience, and with reference to forest dynamics. Specifically, we define forest degradation as a state of anthropogenically induced arrested succession, where ecological processes that underlie forest dynamics are diminished or severely constrained. Metrics of degradation might include those that reflect ecological processes shaping community dynamics, notably the regeneration of plant species. Arrested succession implies that management intervention is necessary to recover successional trajectories. Such a definition can be applied to any forest ecosystem, and can also be extended to other ecosystems. PMID:26411619

  19. Failed fuel degradation

    International Nuclear Information System (INIS)

    Failed fuel degradation is the term used to describe the post-defect deterioration of a fuel rod which can occur under continued operation in certain circumstances. Two mechanisms are generally postulated for failed fuel degradation in light water reactors. The first of these attributes degradation susceptibility (axial split formation) to the inherently low fracture toughness of the zircaloy cladding exacerbated by hydrogen embrittlement. The second mechanism attributes the degradation to the reduced relative corrosion resistance of the zirconium liner present in barrier fuel. This leads to a greater fuel rod internal inventory of embrittling hydrogen in conjunction with increased cladding stresses caused by closure of the pellet-cladding gap due to liner corrosion. Key observations relating to these mechanisms are reviewed and the development of mitigating actions to address them described. Commercial irradiation experience gained with subsequently improved fuel designs is discussed. (5 figures; 7 references) (UK)

  20. REGULATION OF COAL POLYMER DEGRADATION BY FUNGI

    Energy Technology Data Exchange (ETDEWEB)

    John A. Bumpus

    1998-11-30

    A variety of lignin degrading fungi mediate solubilization and subsequent biodegradation of coal macromolecules (a.k.a. coal polymer) from highly oxidized low rank coals such as leonardites. It appears that oxalate or possibly other metal chelators (i.e., certain Krebs Cycle intermediates) mediate solubilization of low rank coals while extracellular oxidases have a role in subsequent oxidation of solubilized coal macromolecule. These processes are under nutritional control. For example, in the case of P. chrysosporium, solubilization of leonardite occurred when the fungi were cultured on most but not all nutrient agars tested and subsequent biodegradation occurred only in nutrient nitrogen limited cultures. Lignin peroxidases mediate oxidation of coal macromolecule in a reaction that is dependent on the presence of veratryl alcohol and hydrogen peroxide. Kinetic evidence suggests that veratryl alcohol is oxidized to the veratryl alcohol cation radical which then mediates oxidation of the coal macromolecule. Results by others suggest that Mn peroxidases mediate formation of reactive Mn{sup 3+} complexes which also mediate oxidation of coal macromolecule. A biomimetic approach was used to study solubilization of a North Dakota leonardite. It was found that a concentration {approximately}75 mM sodium oxalate was optimal for solubilization of this low rank coal. This is important because this is well above the concentration of oxalate produced by fungi in liquid culture. Higher local concentrations probably occur in solid agar cultures and thus may account for the observation that greater solubilization occurs in agar media relative to liquid media. The characteristics of biomimetically solubilized leonardite were similar to those of biologically solubilized leonardite. Perhaps our most interesting observation was that in addition to oxalate, other common Lewis bases (phosphate/hydrogen phosphate/dihydrogen phosphate and bicarbonate/carbonate ions) are able to mediate

  1. Bacteria and lignin degradation

    Institute of Scientific and Technical Information of China (English)

    Jing LI; Hongli YUAN; Jinshui YANG

    2009-01-01

    Lignin is both the most abundant aromatic (phenolic) polymer and the second most abundant raw material.It is degraded and modified by bacteria in the natural world,and bacteria seem to play a leading role in decomposing lignin in aquatic ecosystems.Lignin-degrading bacteria approach the polymer by mechanisms such as tunneling,erosion,and cavitation.With the advantages of immense environmental adaptability and biochemical versatility,bacteria deserve to be studied for their ligninolytic potential.

  2. [Degradation of succinylcholine chloride].

    Science.gov (United States)

    Németh, G; Török, I; Paál, T

    1993-05-01

    Quantitative thin-layer chormatographic method has been developed for the investigation of the degradation of injection formulations containing succinylcholinium chloride. The method is based on the denistometric determination of the main degradation product, choline at 430 nm after visualization with iodine vapour. The stability of the injection was investigated under various storage conditions and it has been stated that considerable decomposition takes place during as short a period as one week. PMID:8362654

  3. Determinants of Swe1p Degradation in Saccharomyces cerevisiae

    OpenAIRE

    McMillan, John N.; Theesfeld, Chandra L.; Harrison, Jacob C.; Bardes, Elaine S.G.; Lew, Daniel J.

    2002-01-01

    Swe1p, the sole Wee1-family kinase in Saccharomyces cerevisiae, is synthesized during late G1 and is then degraded as cells proceed through the cell cycle. However, Swe1p degradation is halted by the morphogenesis checkpoint, which responds to insults that perturb bud formation. The Swe1p stabilization promotes cell cycle arrest through Swe1p-mediated inhibitory phosphorylation of Cdc28p until the cells can recover from the perturbation and resume bud formation. Swe1p degradation involves the...

  4. Drift Degradation Analysis

    International Nuclear Information System (INIS)

    Degradation of underground openings as a function of time is a natural and expected occurrence for any subsurface excavation. Over time, changes occur to both the stress condition and the strength of the rock mass due to several interacting factors. Once the factors contributing to degradation are characterized, the effects of drift degradation can typically be mitigated through appropriate design and maintenance of the ground support system. However, for the emplacement drifts of the geologic repository at Yucca Mountain, it is necessary to characterize drift degradation over a 10,000-year period, which is well beyond the functional period of the ground support system. This document provides an analysis of the amount of drift degradation anticipated in repository emplacement drifts for discrete events and time increments extending throughout the 10,000-year regulatory period for postclosure performance. This revision of the drift degradation analysis was developed to support the license application and fulfill specific agreement items between the U.S. Nuclear Regulatory Commission (NRC) and the U.S. Department of Energy (DOE). The earlier versions of ''Drift Degradation Analysis'' (BSC 2001 [DIRS 156304]) relied primarily on the DRKBA numerical code, which provides for a probabilistic key-block assessment based on realistic fracture patterns determined from field mapping in the Exploratory Studies Facility (ESF) at Yucca Mountain. A key block is defined as a critical block in the surrounding rock mass of an excavation, which is removable and oriented in an unsafe manner such that it is likely to move into an opening unless support is provided. However, the use of the DRKBA code to determine potential rockfall data at the repository horizon during the postclosure period has several limitations: (1) The DRKBA code cannot explicitly apply dynamic loads due to seismic ground motion. (2) The DRKBA code cannot explicitly apply loads due to thermal stress. (3) The DRKBA

  5. Drift Degradation Analysis

    Energy Technology Data Exchange (ETDEWEB)

    D. Kicker

    2004-09-16

    Degradation of underground openings as a function of time is a natural and expected occurrence for any subsurface excavation. Over time, changes occur to both the stress condition and the strength of the rock mass due to several interacting factors. Once the factors contributing to degradation are characterized, the effects of drift degradation can typically be mitigated through appropriate design and maintenance of the ground support system. However, for the emplacement drifts of the geologic repository at Yucca Mountain, it is necessary to characterize drift degradation over a 10,000-year period, which is well beyond the functional period of the ground support system. This document provides an analysis of the amount of drift degradation anticipated in repository emplacement drifts for discrete events and time increments extending throughout the 10,000-year regulatory period for postclosure performance. This revision of the drift degradation analysis was developed to support the license application and fulfill specific agreement items between the U.S. Nuclear Regulatory Commission (NRC) and the U.S. Department of Energy (DOE). The earlier versions of ''Drift Degradation Analysis'' (BSC 2001 [DIRS 156304]) relied primarily on the DRKBA numerical code, which provides for a probabilistic key-block assessment based on realistic fracture patterns determined from field mapping in the Exploratory Studies Facility (ESF) at Yucca Mountain. A key block is defined as a critical block in the surrounding rock mass of an excavation, which is removable and oriented in an unsafe manner such that it is likely to move into an opening unless support is provided. However, the use of the DRKBA code to determine potential rockfall data at the repository horizon during the postclosure period has several limitations: (1) The DRKBA code cannot explicitly apply dynamic loads due to seismic ground motion. (2) The DRKBA code cannot explicitly apply loads due to thermal

  6. Characterization of Methane Degradation and Methane-Degrading Microbes in Alaska Coastal Water

    Energy Technology Data Exchange (ETDEWEB)

    Kirchman, David L. [Univ. of Delaware, Lewes, DE (United States)

    2012-03-29

    The net flux of methane from methane hydrates and other sources to the atmosphere depends on methane degradation as well as methane production and release from geological sources. The goal of this project was to examine methane-degrading archaea and organic carbon oxidizing bacteria in methane-rich and methane-poor sediments of the Beaufort Sea, Alaska. The Beaufort Sea system was sampled as part of a multi-disciplinary expedition (Methane in the Arctic Shelf or MIDAS) in September 2009. Microbial communities were examined by quantitative PCR analyses of 16S rRNA genes and key methane degradation genes (pmoA and mcrA involved in aerobic and anaerobic methane degradation, respectively), tag pyrosequencing of 16S rRNA genes to determine the taxonomic make up of microbes in these sediments, and sequencing of all microbial genes (metagenomes ). The taxonomic and functional make-up of the microbial communities varied with methane concentrations, with some data suggesting higher abundances of potential methane-oxidizing archaea in methane-rich sediments. Sequence analysis of PCR amplicons revealed that most of the mcrA genes were from the ANME-2 group of methane oxidizers. According to metagenomic data, genes involved in methane degradation and other degradation pathways changed with sediment depth along with sulfate and methane concentrations. Most importantly, sulfate reduction genes decreased with depth while the anaerobic methane degradation gene (mcrA) increased along with methane concentrations. The number of potential methane degradation genes (mcrA) was low and inconsistent with other data indicating the large impact of methane on these sediments. The data can be reconciled if a small number of potential methane-oxidizing archaea mediates a large flux of carbon in these sediments. Our study is the first to report metagenomic data from sediments dominated by ANME-2 archaea and is one of the few to examine the entire microbial assemblage potentially involved in

  7. Mediatized Humanitarianism

    DEFF Research Database (Denmark)

    Vestergaard, Anne

    2014-01-01

    The article investigates the implications of mediatization for the legitimation strategies of humanitarian organizations. Based on a (full population) corpus of ~400 pages of brochure material from 1970 to 2007, the micro-textual processes involved in humanitarian organizations' efforts to...... legitimate themselves and their moral claim were examined. A time trend analysis of the prioritization of actors in the material indicates that marked shifts in legitimation loci have taken place during the past 40 years. A discourse analysis unfolds the three dominant discourses behind these shifts, namely...... legitimation by accountancy, legitimation by institutionalization, and legitimation by compensation. The analysis relates these changes to a problem of trust associated with mediatization through processes of mediation....

  8. Motor degradation prediction methods

    International Nuclear Information System (INIS)

    Motor Operated Valve (MOV) squirrel cage AC motor rotors are susceptible to degradation under certain conditions. Premature failure can result due to high humidity/temperature environments, high running load conditions, extended periods at locked rotor conditions (i.e. > 15 seconds) or exceeding the motor's duty cycle by frequent starts or multiple valve stroking. Exposure to high heat and moisture due to packing leaks, pressure seal ring leakage or other causes can significantly accelerate the degradation. ComEd and Liberty Technologies have worked together to provide and validate a non-intrusive method using motor power diagnostics to evaluate MOV rotor condition and predict failure. These techniques have provided a quick, low radiation dose method to evaluate inaccessible motors, identify degradation and allow scheduled replacement of motors prior to catastrophic failures

  9. Motor degradation prediction methods

    Energy Technology Data Exchange (ETDEWEB)

    Arnold, J.R.; Kelly, J.F.; Delzingaro, M.J.

    1996-12-01

    Motor Operated Valve (MOV) squirrel cage AC motor rotors are susceptible to degradation under certain conditions. Premature failure can result due to high humidity/temperature environments, high running load conditions, extended periods at locked rotor conditions (i.e. > 15 seconds) or exceeding the motor`s duty cycle by frequent starts or multiple valve stroking. Exposure to high heat and moisture due to packing leaks, pressure seal ring leakage or other causes can significantly accelerate the degradation. ComEd and Liberty Technologies have worked together to provide and validate a non-intrusive method using motor power diagnostics to evaluate MOV rotor condition and predict failure. These techniques have provided a quick, low radiation dose method to evaluate inaccessible motors, identify degradation and allow scheduled replacement of motors prior to catastrophic failures.

  10. PWR degraded core analysis

    International Nuclear Information System (INIS)

    A review is presented of the various phenomena involved in degraded core accidents and the ensuing transport of fission products from the fuel to the primary circuit and the containment. The dominant accident sequences found in the PWR risk studies published to date are briefly described. Then chapters deal with the following topics: the condition and behaviour of water reactor fuel during normal operation and at the commencement of degraded core accidents; the generation of hydrogen from the Zircaloy-steam and the steel-steam reactions; the way in which the core deforms and finally melts following loss of coolant; debris relocation analysis; containment integrity; fission product behaviour during a degraded core accident. (U.K.)

  11. Degradation effects in polymers

    International Nuclear Information System (INIS)

    The extremely long molecular chains of polymers can be broken easily by the absorption of a quantum of energy above the energy of the covalent bond of the main carbon chain, which typically is in the range of 5-10 eV. The energy of beta and gamma photons of 1 to 10 MeV surpasses by many orders of magnitude this minimum value, representing a high risk of degradation to all kind of polymers, naturals and synthetics alike. The protection of polymers against high doses (20 - 1000 kGy) requires efficient additives preventing and/or stopping chain reaction type oxidative degradation. Primary and secondary antioxidants work well here in synergy. Commercial raw materials are available for radiation-sterilizable medical devices made out of polyolefins and other thermoplastics. Similarly, polymer compounds of suitable formulae are offered commercially for high-dose applications of polymers in nuclear installations. The controlled degradation of polymers of large molecular mass - or even of cross-linked molecular structures - is a promising field of radiation application. One area here is related to recycling non-accessible polymers such as fluorinated plastics of cross-linked rubber products. Another large possible area is the controlled radiation degradation of natural polymer systems. Radiation may facilitate the access to cross-linked natural polymer systems, such as wood, plant cellulose and biomass in general, decreasing to use of aggressive chemicals. The result is energetically favorable, environmentally friendly new procedures and raw materials of natural origin. A limited dose applied to polymers - although may cause some degradation - however may initiate new bonds on the 'wounded' chain. The popular graft-copolymerization technique can be applied in new, up-coming polymer processing technologies such as alloying, composite processing and reconstitutive recycling. By this way, even those polymers described earlier as radiation-degrading types, can be cross

  12. Mediatized play

    DEFF Research Database (Denmark)

    Johansen, Stine Liv

    Children’s play must nowadays be understood as a mediatized field in society and culture. Media – understood in a very broad sense - holds severe explanatory power in describing and understanding the practice of play, since play happens both with, through and inspired by media of different sorts........ In this presentation the case of ‘playing soccer’ will be outlined through its different mediated manifestations, including soccer games and programs on TV, computer games, magazines, books, YouTube videos and soccer trading cards....

  13. Mediating Business

    DEFF Research Database (Denmark)

    "Mediating Business" is a study of the expansion of business journalism. Building on evidence from Denmark, Finland, Norway and Sweden, "Mediating Business" is a comparative and multidisciplinary study of one of the major transformations of the mass media and the realm of business - nationally and...... globally. The book explores the history of key innovations and innovators in the business press. It analyzes changes in the discourse of business journalism associated with the growth in business news and the development of new ways of framing business issues and events. Finally, it examines the...... organizational implications of the increased media visibility of business and, in particular, the development of corporate governance and media relations....

  14. Photovoltaic Degradation Risk: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Jordan, D. C.; Kurtz, S. R.

    2012-04-01

    The ability to accurately predict power delivery over the course of time is of vital importance to the growth of the photovoltaic (PV) industry. Important cost drivers include the efficiency with which sunlight is converted into power, how this relationship changes over time, and the uncertainty in this prediction. An accurate quantification of power decline over time, also known as degradation rate, is essential to all stakeholders - utility companies, integrators, investors, and researchers alike. In this paper we use a statistical approach based on historical data to quantify degradation rates, discern trends and quantify risks related to measurement uncertainties, number of measurements and methodologies.

  15. Antifoam degradation testing

    Energy Technology Data Exchange (ETDEWEB)

    Lambert, D. P. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River Ecology Lab. (SREL); Zamecnik, J. R. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River Ecology Lab. (SREL); Newell, D. D. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River Ecology Lab. (SREL); Williams, M. S. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River Ecology Lab. (SREL)

    2015-08-20

    This report describes the results of testing to quantify the degradation products resulting from the dilution and storage of Antifoam 747. Antifoam degradation is of concern to the Defense Waste Processing Facility (DWPF) due to flammable decomposition products in the vapor phase of the Chemical Process Cell vessels, as well as the collection of flammable and organic species in the offgas condensate. The discovery that hexamethyldisiloxane is formed from the antifoam decomposition was the basis for a Potential Inadequacy in the Safety Analysis declaration by the DWPF.

  16. Degradation of fluorotelomer alcohols

    DEFF Research Database (Denmark)

    Ellis, David A; Martin, Jonathan W; De Silva, Amila O;

    2004-01-01

    atmosphere to yield a homologous series of PFCAs. Atmospheric degradation of FTOHs is likely to contribute to the widespread dissemination of PFCAs. After their bioaccumulation potential is accounted for, the pattern of PFCAs yielded from FTOHs could account for the distinct contamination profile of PFCAs...... significance of the gas-phase peroxy radical cross reactions that produce PFCAs has not been recognized previously. Such reactions are expected to occur during the atmospheric degradation of all polyfluorinated materials, necessitating a reexamination of the environmental fate and impact of this important...

  17. Chlorophyll Degradation in Horticultural Crops

    OpenAIRE

    Kaewsuksaeng, Samak

    2011-01-01

    One of the symptoms of senescence in harvested horticultural crops is the loss of greenness that comes with the degradation of chlorophyll. With senescence, the chlorophyll-degrading enzyme activities such as chlorophyllase, Mg-dechelatase or Mg-dechelation activity, a new chlorophyll-degrading enzyme, pheophytinase, pheophorbidase and chlorophyll-degrading peroxidase, which are involved in chlorophyll degradation, affected greatly in stored horticultural crops. The chlorophyll derivatives, e...

  18. Drift Degradation Analysis

    International Nuclear Information System (INIS)

    The outputs from the drift degradation analysis support scientific analyses, models, and design calculations, including the following: (1) Abstraction of Drift Seepage; (2) Seismic Consequence Abstraction; (3) Structural Stability of a Drip Shield Under Quasi-Static Pressure; and (4) Drip Shield Structural Response to Rock Fall. This report has been developed in accordance with ''Technical Work Plan for: Regulatory Integration Modeling of Drift Degradation, Waste Package and Drip Shield Vibratory Motion and Seismic Consequences'' (BSC 2004 [DIRS 171520]). The drift degradation analysis includes the development and validation of rockfall models that approximate phenomenon associated with various components of rock mass behavior anticipated within the repository horizon. Two drift degradation rockfall models have been developed: the rockfall model for nonlithophysal rock and the rockfall model for lithophysal rock. These models reflect the two distinct types of tuffaceous rock at Yucca Mountain. The output of this modeling and analysis activity documents the expected drift deterioration for drifts constructed in accordance with the repository layout configuration (BSC 2004 [DIRS 172801])

  19. Radiation degradation of silk

    Energy Technology Data Exchange (ETDEWEB)

    Ishida, Kazushige; Kamiishi, Youichi [Textile Research Institute of Gunma, Kiryu, Gunma (Japan); Takeshita, Hidefumi; Yoshii, Fumio; Kume, Tamikazu [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment

    2001-03-01

    Silk fibroin powder was prepared from irradiated silk fibroin fiber by means of only physical treatment. Silk fibroin fiber irradiated with an accelerated electron beam in the dose range of 250 - 1000 kGy was pulverized by using a ball mill. Unirradiated silk fibroin fiber was not pulverized at all. But the more irradiation was increased, the more the conversion efficiency from fiber to powder was increased. The conversion efficiency of silk fibroin fiber irradiated 1000 kGy in oxygen was 94%. Silk fibroin powder shows remarkable solubility, which dissolved 57% into water of ambient temperature. It is a very interesting phenomenon that silk fibroin which did not treat with chemicals gets solubility only being pulverized. In order to study mechanism of solubilization of silk fibroin powder, amino acid component of soluble part of silk fibroin powder was analyzed. The more irradiation dose up, the more glycine or alanine degraded, but degradation fraction reached bounds about 50%. Other amino acids were degraded only 20% even at the maximum. To consider crystal construction of silk fibroin, it is suggested that irradiation on silk fibroin fiber selectively degrades glycine and alanine in amorphous region, which makes it possible to pulverize and to dissolve silk fibroin powder. (author)

  20. North American Soil Degradation: Processes, Practices, and Mitigating Strategies

    Directory of Open Access Journals (Sweden)

    R. L. Baumhardt

    2015-03-01

    Full Text Available Soil can be degraded by several natural or human-mediated processes, including wind, water, or tillage erosion, and formation of undesirable physical, chemical, or biological properties due to industrialization or use of inappropriate farming practices. Soil degradation occurs whenever these processes supersede natural soil regeneration and, generally, reflects unsustainable resource management that is global in scope and compromises world food security. In North America, soil degradation preceded the catastrophic wind erosion associated with the dust bowl during the 1930s, but that event provided the impetus to improve management of soils degraded by both wind and water erosion. Chemical degradation due to site specific industrial processing and mine spoil contamination began to be addressed during the latter half of the 20th century primarily through point-source water quality concerns, but soil chemical degradation and contamination of surface and subsurface water due to on-farm non-point pesticide and nutrient management practices generally remains unresolved. Remediation or prevention of soil degradation requires integrated management solutions that, for agricultural soils, include using cover crops or crop residue management to reduce raindrop impact, maintain higher infiltration rates, increase soil water storage, and ultimately increase crop production. By increasing plant biomass, and potentially soil organic carbon (SOC concentrations, soil degradation can be mitigated by stabilizing soil aggregates, improving soil structure, enhancing air and water exchange, increasing nutrient cycling, and promoting greater soil biological activity.

  1. Detection of pump degradation

    Energy Technology Data Exchange (ETDEWEB)

    Greene, R.H.; Casada, D.A.; Ayers, C.W. [and others

    1995-08-01

    This Phase II Nuclear Plant Aging Research study examines the methods of detecting pump degradation that are currently employed in domestic and overseas nuclear facilities. This report evaluates the criteria mandated by required pump testing at U.S. nuclear power plants and compares them to those features characteristic of state-of-the-art diagnostic programs and practices currently implemented by other major industries. Since the working condition of the pump driver is crucial to pump operability, a brief review of new applications of motor diagnostics is provided that highlights recent developments in this technology. The routine collection and analysis of spectral data is superior to all other technologies in its ability to accurately detect numerous types and causes of pump degradation. Existing ASME Code testing criteria do not require the evaluation of pump vibration spectra but instead overall vibration amplitude. The mechanical information discernible from vibration amplitude analysis is limited, and several cases of pump failure were not detected in their early stages by vibration monitoring. Since spectral analysis can provide a wealth of pertinent information concerning the mechanical condition of rotating machinery, its incorporation into ASME testing criteria could merit a relaxation in the monthly-to-quarterly testing schedules that seek to verify and assure pump operability. Pump drivers are not included in the current battery of testing. Operational problems thought to be caused by pump degradation were found to be the result of motor degradation. Recent advances in nonintrusive monitoring techniques have made motor diagnostics a viable technology for assessing motor operability. Motor current/power analysis can detect rotor bar degradation and ascertain ranges of hydraulically unstable operation for a particular pump and motor set. The concept of using motor current or power fluctuations as an indicator of pump hydraulic load stability is presented.

  2. Detection of pump degradation

    International Nuclear Information System (INIS)

    This Phase II Nuclear Plant Aging Research study examines the methods of detecting pump degradation that are currently employed in domestic and overseas nuclear facilities. This report evaluates the criteria mandated by required pump testing at U.S. nuclear power plants and compares them to those features characteristic of state-of-the-art diagnostic programs and practices currently implemented by other major industries. Since the working condition of the pump driver is crucial to pump operability, a brief review of new applications of motor diagnostics is provided that highlights recent developments in this technology. The routine collection and analysis of spectral data is superior to all other technologies in its ability to accurately detect numerous types and causes of pump degradation. Existing ASME Code testing criteria do not require the evaluation of pump vibration spectra but instead overall vibration amplitude. The mechanical information discernible from vibration amplitude analysis is limited, and several cases of pump failure were not detected in their early stages by vibration monitoring. Since spectral analysis can provide a wealth of pertinent information concerning the mechanical condition of rotating machinery, its incorporation into ASME testing criteria could merit a relaxation in the monthly-to-quarterly testing schedules that seek to verify and assure pump operability. Pump drivers are not included in the current battery of testing. Operational problems thought to be caused by pump degradation were found to be the result of motor degradation. Recent advances in nonintrusive monitoring techniques have made motor diagnostics a viable technology for assessing motor operability. Motor current/power analysis can detect rotor bar degradation and ascertain ranges of hydraulically unstable operation for a particular pump and motor set. The concept of using motor current or power fluctuations as an indicator of pump hydraulic load stability is presented

  3. Complement-mediated tail degradation of Neodiplostomum seoulense cercariae

    OpenAIRE

    Park, Yun-Kyu; Hwang, Myung-Ki; Jung, Yun-Jung

    2006-01-01

    The furcocercus cercariae of Neodiplostomum seoulense (Digenea: Neodiplostomidae) penetrate the skins of tadpoles and shed their tails. The speculated mechanism of this tail loss was physical efforts required to produce a vigorous zigzag motion during skin penetration; no other mechanism has been proposed. We examined the relationship between the host serum and cercarial tail loss. Cercariae of N. seoulense were collected from experimentally infected Segmentina hemisphaerula, and lots of 300 ...

  4. Graphene coatings for chemotherapy: avoiding silver-mediated degradation

    Science.gov (United States)

    Mazzola, Federico; Trinh, Thuat; Cooil, Simon; Ramleth Østli, Elise; Høydalsvik, Kristin; Torbjørn Bakken Skjønsfjell, Eirik; Kjelstrup, Signe; Preobrajenski, Alexei; Cafolla, Attilio A.; Evans, D. Andrew; Breiby, Dag W.; Wells, Justin W.

    2015-06-01

    Chemotherapy treatment usually involves the delivery of fluorouracil (5-Fu) together with other drugs through central venous catheters. Catheters and their connectors are increasingly treated with silver or argentic alloys/compounds. Complications arising from broken catheters are common, leading to additional suffering for patients and increased medical costs. Here, we uncover a likely cause of such failure through a study of the surface chemistry relevant to chemotherapy drug delivery, i.e. between 5-Fu and silver. We show that silver catalytically decomposes 5-Fu, compromising the efficacy of the chemotherapy treatment. Furthermore, HF is released as a product, which will be damaging to both patient and catheter. We demonstrate that graphene surfaces inhibit this undesirable reaction and would offer superior performance as nanoscale coatings in cancer treatment applications.

  5. Influence of structure on de degradation with lacase mediator systems

    OpenAIRE

    Almansa, Eva; Andreas, Kandelbauer; Pereira, Luciana; Paulo, Artur Cavaco

    2004-01-01

    A new laccase was purified from Trametes hirsuta IMA2002. The laccase had a molecular mass of 62 kDa and an isoelectric point of pH 7. It had an optimum pH of 3.0 and an optimum temperature of 558C. The laccase was quite stable at 308C and pH 4.0 with a half-life of more than 100 hours. On ABTS, yringaldazide, and DMP the laccase showed KM and Kcat values of 75, 12 and 37 mM and 64, 83 and 54 s_1, respectively. The structurally diverse commercial dyes Indigo Carmine, Lanaset Blue 2R, Diamond ...

  6. Endocytic collagen degradation

    DEFF Research Database (Denmark)

    Madsen, Daniel H.; Jürgensen, Henrik J.; Ingvarsen, Signe;

    2012-01-01

    Fibrosis of the liver and its end-stage, cirrhosis, represent major health problems worldwide. In these fibrotic conditions, activated fibroblasts and hepatic stellate cells display a net deposition of collagen. This collagen deposition is a major factor leading to liver dysfunction, thus making it...... crucially important to understand both the collagen synthesis and turnover mechanisms in this condition. Here we show that the endocytic collagen receptor, uPARAP/Endo180, is a major determinant in governing the balance between collagen deposition and degradation. Cirrhotic human livers displayed a marked...... up-regulation of uPARAP/Endo180 in activated fibroblasts and hepatic stellate cells located close to the collagen deposits. In a hepatic stellate cell line, uPARAP/Endo180 was shown to be active in, and required for, the uptake and intracellular degradation of collagen. To evaluate the functional...

  7. Prolamin degradation in sourdoughs

    OpenAIRE

    Loponen, Jussi

    2006-01-01

    This thesis examines protein behaviours that occur during cereal fermentations. The focus is on the prolamin degradation in sourdoughs. The thesis also looks at what happens to the oat globulins during an oat bran acidification process. The cereal prolamins are unique proteins in many respects. The wheat prolamins (glutenins and gliadins) are responsible for the formation of the gluten that provides the viscoelastic properties to wheat doughs whereas the rye prolamins (secalins) are unab...

  8. Detection of pump degradation

    Energy Technology Data Exchange (ETDEWEB)

    Casada, D. [Oak Ridge National Lab., TN (United States)

    1995-04-01

    There are a variety of stressors that can affect the operation of centrifugal pumps. Although these general stressors are active in essentially all centrifugal pumps, the stressor level and the extent of wear and degradation can vary greatly. Parameters that affect the extent of stressor activity are manifold. In order to assure the long-term operational readiness of a pump, it is important to both understand the nature and magnitude of the specific degradation mechanisms and to monitor the performance of the pump. The most commonly applied method of monitoring the condition of not only pumps, but rotating machinery in general, is vibration analysis. Periodic or continuous special vibration analysis is a cornerstone of most pump monitoring programs. In the nuclear industry, non-spectral vibration monitoring of safety-related pumps is performed in accordance with the ASME code. Pump head and flow rate are also monitored, per code requirements. Although vibration analysis has dominated the condition monitoring field for many years, there are other measures that have been historically used to help understand pump condition; advances in historically applied technologies and developing technologies offer improved monitoring capabilities. The capabilities of several technologies (including vibration analysis, dynamic pressure analysis, and motor power analysis) to detect the presence and magnitude of both stressors and resultant degradation are discussed.

  9. Detection of pump degradation

    International Nuclear Information System (INIS)

    There are a variety of stressors that can affect the operation of centrifugal pumps. Although these general stressors are active in essentially all centrifugal pumps, the stressor level and the extent of wear and degradation can vary greatly. Parameters that affect the extent of stressor activity are manifold. In order to assure the long-term operational readiness of a pump, it is important to both understand the nature and magnitude of the specific degradation mechanisms and to monitor the performance of the pump. The most commonly applied method of monitoring the condition of not only pumps, but rotating machinery in general, is vibration analysis. Periodic or continuous spectral vibration analysis is a cornerstone of most pump monitoring programs. In the nuclear industry, non-spectral vibration monitoring of safety-related pumps is performed in accordance with the ASME code. Although vibration analysis has dominated the condition monitoring field for many years, there are other measures that have been historically used to help understand pump condition: advances in historically applied technologies and developing technologies offer improved monitoring capabilities. The capabilities of several technologies (including vibration analysis, dynamic pressure analysis, and motor power analysis) to detect the presence and magnitude of both stressors and resultant degradation are discussed

  10. Fungal Laccases Degradation of Endocrine Disrupting Compounds

    Directory of Open Access Journals (Sweden)

    Gemma Macellaro

    2014-01-01

    Full Text Available Over the past decades, water pollution by trace organic compounds (ng/L has become one of the key environmental issues in developed countries. This is the case of the emerging contaminants called endocrine disrupting compounds (EDCs. EDCs are a new class of environmental pollutants able to mimic or antagonize the effects of endogenous hormones, and are recently drawing scientific and public attention. Their widespread presence in the environment solicits the need of their removal from the contaminated sites. One promising approach to face this challenge consists in the use of enzymatic systems able to react with these molecules. Among the possible enzymes, oxidative enzymes are attracting increasing attention because of their versatility, the possibility to produce them on large scale, and to modify their properties. In this study five different EDCs were treated with four different fungal laccases, also in the presence of both synthetic and natural mediators. Mediators significantly increased the efficiency of the enzymatic treatment, promoting the degradation of substrates recalcitrant to laccase oxidation. The laccase showing the best performances was chosen to further investigate its oxidative capabilities against micropollutant mixtures. Improvement of enzyme performances in nonylphenol degradation rate was achieved through immobilization on glass beads.

  11. Ordered bulk degradation via autophagy

    DEFF Research Database (Denmark)

    Dengjel, Jörn; Kristensen, Anders Riis; Andersen, Jens S

    2008-01-01

    proteasomal and lysosomal degradation ample cross-talk between the two degradation pathways became evident. Degradation via autophagy appeared to be ordered and regulated at the protein complex/organelle level. This raises several important questions such as: can macroautophagy itself be specific and what is...

  12. Curcumin inhibits HIV-1 by promoting Tat protein degradation

    Science.gov (United States)

    Ali, Amjad; Banerjea, Akhil C.

    2016-01-01

    HIV-1 Tat is an intrinsically unfolded protein playing a pivotal role in viral replication by associating with TAR region of viral LTR. Unfolded proteins are degraded by 20S proteasome in an ubiquitin independent manner. Curcumin is known to activate 20S proteasome and promotes the degradation of intrinsically unfolded p53 tumor suppressor protein. Since HIV-1 Tat protein is largerly unfolded, we hypothesized that Tat may also be targeted through this pathway. Curcumin treated Tat transfected HEK-293T cells showed a dose and time dependent degradation of Tat protein. Contrary to this HIV-1 Gag which is a properly folded protein, remained unaffected with curcumin. Semi-quantitative RT-PCR analysis showed that curcumin treatment did not affect Tat gene transcription. Curcumin increased the rate of Tat protein degradation as shown by cycloheximide (CHX) chase assay. Degradation of the Tat protein is accomplished through proteasomal pathway as proteasomal inhibitor MG132 blocked Tat degradation. Curcumin also decreased Tat mediated LTR promoter transactivation and inhibited virus production from HIV-1 infected cells. Taken together our study reveals a novel observation that curcumin causes potent degradation of Tat which may be one of the major mechanisms behind its anti HIV activity. PMID:27283735

  13. Edaravone suppresses degradation of type II collagen.

    Science.gov (United States)

    Huang, Chen; Liao, Guangjun; Han, Jian; Zhang, Guofeng; Zou, Benguo

    2016-05-13

    Osteoarthritis (OA) is a degenerative joint disease affecting millions of people. The degradation and loss of type II collagen induced by proinflammatory cytokines secreted by chondrocytes, such as factor-α (TNF-α) is an important pathological mechanism to the progression of OA. Edaravone is a potent free radical scavenger, which has been clinically used to treat the neuronal damage following acute ischemic stroke. However, whether Edaravone has a protective effect in articular cartilage hasn't been reported before. In this study, we investigated the chondrocyte protective effects of Edaravone on TNF-α induced degradation of type Ⅱ collagen. And our results indicated that TNF-α treatment resulted in degradation of type Ⅱ collagen, which can be ameliorated by treatment with Edaravone in a dose dependent manner. Notably, it was found that the inhibitory effects of Edaravone on TNF-α-induced reduction of type Ⅱ collagen were mediated by MMP-3 and MMP-13. Mechanistically, we found that Edaravone alleviated TNF-α induced activation of STAT1 and expression of IRF-1. These findings suggest a potential protective effect of Edaravone in OA. PMID:27037019

  14. Different pathways of degradation of SP-A and saturated phosphatidylcholine by alveolar macrophages.

    Science.gov (United States)

    Baritussio, A; Alberti, A; Armanini, D; Meloni, F; Bruttomesso, D

    2000-07-01

    Alveolar macrophages degrade surfactant protein (SP) A and saturated phosphatidycholine [dipalmitoylphosphatidylcholine (DPPC)]. To clarify this process, using rabbit alveolar macrophages, we analyzed the effect of drugs known to affect phagocytosis, pinocytosis, clathrin-mediated uptake, caveolae, the cytoskeleton, lysosomal pH, protein kinase C, and phosphatidylinositol 3-kinase (PI3K) on the degradation of SP-A and DPPC. We found the following: 1) SP-A binds to the plasma membrane, is rapidly internalized, and then moves toward degradative compartments. Uptake could be clathrin mediated, whereas phagocytosis, pinocytosis, or the use of caveolae are less likely. An intact cytoskeleton and an acidic milieu are necessary for the degradation of SP-A. 2) Stimulation of protein kinase C increases the degradation of SP-A. 3) PI3K influences the degradation of SP-A by regulating both the speed of internalization and subsequent intracellular steps, but its inhibition does not prevent SP-A from reaching the lysosomal compartment. 4) The degradation of DPPC is unaffected by most of the treatments able to influence the degradation of SP-A. Thus it appears that DPPC is degraded by alveolar macrophages through mechanisms very different from those utilized for the degradation of SP-A. PMID:10893207

  15. Degradation analysis of REBCO coils

    International Nuclear Information System (INIS)

    RE-Ba-Cu-O (REBCO) layer-wound coils were operated to investigate their properties under electromagnetic forces in an external magnetic field of up to 17.2 T. While REBCO coils were successfully operated under electromagnetic forces over 200 MPa, some showed degradation after quenching. To develop high-temperature superconducting (HTS) magnets, the reasons for the degradation of REBCO coils should be investigated. In this study, the degraded REBCO coils were carefully rewound. The critical current (Ic) of the rewound REBCO conductor was measured to check the damaged parts in the degraded REBCO coils, and the possible causes for the degradation were discussed. (paper)

  16. Carbon isotope effects associated with Fenton-like degradation of toluene: Potential for differentiation of abiotic and biotic degradation

    International Nuclear Information System (INIS)

    Hydrogen peroxide (H2O2)-mediated oxygenation to enhance subsurface aerobic biodegradation is a frequently employed remediation technique. However, it may be unclear whether observed organic contaminant mass loss is caused by biodegradation or chemical oxidation via hydroxyl radicals generated during catalyzed Fenton-like reactions. Compound-specific carbon isotope analysis has the potential to discriminate between these processes. Here we report laboratory experiments demonstrating no significant carbon isotope fractionation during Fenton-like hydroxyl radical oxidation of toluene. This implies that observation of significant isotopic fractionation of toluene at a site undergoing H2O2-mediated remediation would provide direct evidence of biodegradation. We applied this approach at a field site that had undergone 27 months of H2O2-mediated subsurface oxygenation. Despite substantial decreases (> 68%) in groundwater toluene concentrations carbon isotope signatures of toluene (δ13Ctol) showed no significant variation (mean = - 27.5 ±0.3 per mille, n = 13) over a range of concentrations from 11.1 to 669.0 mg L-1. Given that aerobic degradation by ring attack has also been shown to result in no significant isotopic fractionation during degradation, at this site we were unable to discern the mechanism of degradation. However, such differentiation is possible at sites where aerobic degradation by methyl group attack results in significant isotopic fractionation

  17. Outdoor PV Degradation Comparison

    Energy Technology Data Exchange (ETDEWEB)

    Jordan, D. C.; Smith, R. M.; Osterwald, C. R.; Gelak, E.; Kurtz, S. R.

    2011-02-01

    As photovoltaic (PV) penetration of the power grid increases, it becomes vital to know how decreased power output; may affect cost over time. In order to predict power delivery, the decline or degradation rates must be determined; accurately. At the Performance and Energy Rating Testbed (PERT) at the Outdoor Test Facility (OTF) at the; National Renewable Energy Laboratory (NREL) more than 40 modules from more than 10 different manufacturers; were compared for their long-term outdoor stability. Because it can accommodate a large variety of modules in a; limited footprint the PERT system is ideally suited to compare modules side-by-side under the same conditions.

  18. Bacterial Degradation of Pesticides

    DEFF Research Database (Denmark)

    Knudsen, Berith Elkær

    This PhD project was carried out as part of the Microbial Remediation of Contaminated Soil and Water Resources (MIRESOWA) project, funded by the Danish Council for Strategic Research (grant number 2104-08-0012). The environment is contaminated with various xenobiotic compounds e.g. pesticides......D student, to construct fungal-bacterial consortia in order to potentially stimulate pesticide degradation thereby increasing the chance of successful bioaugmentation. The results of the project are reported in three article manuscripts, included in this thesis. In manuscript I, the mineralization of 2...

  19. Degradation of copepod fecal pellets

    DEFF Research Database (Denmark)

    Poulsen, Louise K.; Iversen, Morten

    2008-01-01

    Copepod fecal pellets are often degraded at high rates within the upper part of the water column. However, the identity of the degraders and the processes governing the degradation remain unresolved. To identify the pellet degraders we collected water from Oresund (Denmark) approximately every...... second month from July 2004 to July 2005. These water samples were divided into 5 fractions (<0.2, <2, <20, <100, <200 mu m) and total (unfractionated). We determined fecal pellet degradation rate and species composition of the plankton from triplicate incubations of each fraction and a known, added...... amount of fecal pellets. The total degradation rate of pellets by the natural plankton community of Oresund followed the phytoplankton biomass, with maximum degradation rate during the spring bloom (2.5 +/- 0.49 d(-1)) and minimum (0.52 +/- 0.14 d(-1)) during late winter. Total pellet removal rate ranged...

  20. PRACTICAL ASPECTS OF MEDIATION

    OpenAIRE

    IULIA FLOCA

    2011-01-01

    Today the Romanian state gives some advantages to those who use mediation. If the Romanian state would take further steps, mediation would work as in the countries with old tradition. The article refers to success and failure got in the two years of practice. The mediation can be seen in two aspects: The first aspect regarding the mediation itself can lead to a mediation agreement. The mediation agreement gives both winnings to the conflict parts and professional satisfactions to the mediator...

  1. Ecosystems degradation on Romania’s Territory

    OpenAIRE

    Giani GRĂDINARU

    2010-01-01

    The paper presents results of 20 developing econometric models on which were determined and analyzed ecosystem degradation rates in Romania: air quality degradation rates, soil quality degradation rates and biodiversity degradation rates.

  2. Radiation degradation of cellulose

    International Nuclear Information System (INIS)

    The application of straw and other cellulose polymers as feedstuff for ruminants is limited by its low digestibility. During recent decades it was attempted to increase the digestibility of straw by several chemical and physical methods. In this work some results of the degradation of gamma and electron treated wheat straw are reported. Complex methods of treatment (e.g. radiation influence and influence of lyes) are taken into consideration. In vitro-experiments with radiation treated straw show that the digestibility can be increased from 20% up to about 80%. A high pressure liquid chromatography method was used to analyze the hydrolysates. The contents of certain species of carbohydrates in the hydrolysates in dependence on the applied dose are given

  3. Thermal battery degradation mechanisms

    Energy Technology Data Exchange (ETDEWEB)

    Missert, Nancy A. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Brunke, Lyle Brent [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-09-01

    Diffuse reflectance IR spectroscopy (DRIFTS) was used to investigate the effect of accelerated aging on LiSi based anodes in simulated MC3816 batteries. DRIFTS spectra showed that the oxygen, carbonate, hydroxide and sulfur content of the anodes changes with aging times and temperatures, but not in a monotonic fashion that could be correlated to phase evolution. Bands associated with sulfur species were only observed in anodes taken from batteries aged in wet environments, providing further evidence for a reaction pathway facilitated by H2S transport from the cathode, through the separator, to the anode. Loss of battery capacity with accelerated aging in wet environments was correlated to loss of FeS2 in the catholyte pellets, suggesting that the major contribution to battery performance degradation results from loss of active cathode material.

  4. A Porous Tissue Engineering Scaffold Selectively Degraded by Cell-Generated Reactive Oxygen Species

    Science.gov (United States)

    Martin, John R.; Gupta, Mukesh K.; Page, Jonathan M.; Yu, Fang; Davidson, Jeffrey M.; Guelcher, Scott A.

    2014-01-01

    Biodegradable tissue engineering scaffolds are commonly fabricated from poly(lactide-co-glycolide) (PLGA) or similar polyesters that degrade by hydrolysis. PLGA hydrolysis generates acidic breakdown products that trigger an accelerated, autocatalytic degradation mechanism that can create mismatched rates of biomaterial breakdown and tissue formation. Reactive oxygen species (ROS) are key mediators of cell function in both health and disease, especially at sites of inflammation and tissue healing, and induction of inflammation and ROS are natural components of the in vivo response to biomaterial implantation. Thus, polymeric biomaterials that are selectively degraded by cell-generated ROS may have potential for creating tissue engineering scaffolds with better matched rates of tissue in-growth and cell-mediated scaffold biodegradation. To explore this approach, a series of poly(thioketal) (PTK) urethane (PTK-UR) biomaterial scaffolds were synthesized that degrade specifically by an ROS-dependent mechanism. PTK-UR scaffolds had significantly higher compressive moduli than analogous poly(ester urethane) (PEUR) scaffolds formed from hydrolytically-degradable ester-based diols (p < 0.05). Unlike PEUR scaffolds, the PTK-UR scaffolds were stable under aqueous conditions out to 25 weeks but were selectively degraded by ROS, indicating that their biodegradation would be exclusively cell-mediated. The in vitro oxidative degradation rates of the PTK-URs followed first-order degradation kinetics, were significantly dependent on PTK composition (p < 0.05), and correlated to ROS concentration. In subcutaneous rat wounds, PTK-UR scaffolds supported cellular infiltration and granulation tissue formation, followed first-order degradation kinetics over 7 weeks, and produced significantly greater stenting of subcutaneous wounds compared to PEUR scaffolds. These combined results indicate that ROS-degradable PTK-UR tissue engineering scaffolds have significant advantages over analogous

  5. Degradation of microinjected proteins: the role of substrate flexibility

    Energy Technology Data Exchange (ETDEWEB)

    Rote, K.V.

    1985-01-01

    RB-mediated microinjection was used to introduce radioiodinated proteins of similar structure, but diverse flexibilities, into HeLa cells. Rates of intracellular degradation were then measured by release of /sup 125/I-tyrosine into the media. Ribonuclease-A was much more stable to degradation by trypsin, pepsin, or papain than its relatively flexible derivatives ribonuclease-S and S-protein. Likewise, ribonuclease-S and S-protein were degraded more quickly in reticulocyte lysates than ribonuclease-A. In contrast, all three proteins displayed similar, if not identical, half-lives in vivo. Similarly, intracellular half-lives of anhydrotrypsin and various proteinaceous trypsin inhibitors were in the same range whether they were measured in the free state or following complex formation, which drastically decreases flexibility. Trypsinogen, which contains a relatively flexible activation domain, was degraded more slowly than anhydrotrypsin. Nondenaturing agarose or polyacrylamide gel electrophoresis of microinjected cell lysates revealed that complexes of trypsin and its inhibitors remained intact following radioiodination and introduction into cells, and are therefore degraded as a unit. All microinjected proteins remained in their unbound, unprocessed forms prior to degradation.

  6. Degradation of microinjected proteins: the role of substrate flexibility

    International Nuclear Information System (INIS)

    RB-mediated microinjection was used to introduce radioiodinated proteins of similar structure, but diverse flexibilities, into HeLa cells. Rates of intracellular degradation were then measured by release of 125I-tyrosine into the media. Ribonuclease-A was much more stable to degradation by trypsin, pepsin, or papain than its relatively flexible derivatives ribonuclease-S and S-protein. Likewise, ribonuclease-S and S-protein were degraded more quickly in reticulocyte lysates than ribonuclease-A. In contrast, all three proteins displayed similar, if not identical, half-lives in vivo. Similarly, intracellular half-lives of anhydrotrypsin and various proteinaceous trypsin inhibitors were in the same range whether they were measured in the free state or following complex formation, which drastically decreases flexibility. Trypsinogen, which contains a relatively flexible activation domain, was degraded more slowly than anhydrotrypsin. Nondenaturing agarose or polyacrylamide gel electrophoresis of microinjected cell lysates revealed that complexes of trypsin and its inhibitors remained intact following radioiodination and introduction into cells, and are therefore degraded as a unit. All microinjected proteins remained in their unbound, unprocessed forms prior to degradation

  7. Determinants of Swe1p Degradation in Saccharomyces cerevisiae

    Science.gov (United States)

    McMillan, John N.; Theesfeld, Chandra L.; Harrison, Jacob C.; Bardes, Elaine S. G.; Lew, Daniel J.

    2002-01-01

    Swe1p, the sole Wee1-family kinase in Saccharomyces cerevisiae, is synthesized during late G1 and is then degraded as cells proceed through the cell cycle. However, Swe1p degradation is halted by the morphogenesis checkpoint, which responds to insults that perturb bud formation. The Swe1p stabilization promotes cell cycle arrest through Swe1p-mediated inhibitory phosphorylation of Cdc28p until the cells can recover from the perturbation and resume bud formation. Swe1p degradation involves the relocalization of Swe1p from the nucleus to the mother-bud neck, and neck targeting requires the Swe1p-interacting protein Hsl7p. In addition, Swe1p degradation is stimulated by its substrate, cyclin/Cdc28p, and Swe1p is thought to be a target of the ubiquitin ligase SCFMet30 acting with the ubiquitin-conjugating enzyme Cdc34p. The basis for regulation of Swe1p degradation by the morphogenesis checkpoint remains unclear, and in order to elucidate that regulation we have dissected the Swe1p degradation pathway in more detail, yielding several novel findings. First, we show here that Met30p (and by implication SCFMet30) is not, in fact, required for Swe1p degradation. Second, cyclin/Cdc28p does not influence Swe1p neck targeting, but can directly phosphorylate Swe1p, suggesting that it acts downstream of neck targeting in the Swe1p degradation pathway. Third, a screen for functional but nondegradable mutants of SWE1 identified two small regions of Swe1p that are key to its degradation. One of these regions mediates interaction of Swe1p with Hsl7p, showing that the Swe1p-Hsl7p interaction is critical for Swe1p neck targeting and degradation. The other region did not appear to affect interactions with known Swe1p regulators, suggesting that other as-yet-unknown regulators exist. PMID:12388757

  8. Targeting Notch degradation system provides promise for breast cancer therapeutics.

    Science.gov (United States)

    Liu, Jing; Shen, Jia-Xin; Wen, Xiao-Fen; Guo, Yu-Xian; Zhang, Guo-Jun

    2016-08-01

    Notch receptor signaling pathways play an important role, not only in normal breast development but also in breast cancer development and progression. As a group of ligand-induced proteins, different subtypes of mammalian Notch (Notch1-4) are sensitive to subtle changes in protein levels. Thus, a clear understanding of mechanisms of Notch protein turnover is essential for understanding normal and pathological mechanisms of Notch functions. It has been suggested that there is a close relationship between the carcinogenesis and the dysregulation of Notch degradation. However, this relationship remains mostly undefined in the context of breast cancer, as protein degradation is mediated by numerous signaling pathways as well as certain molecule modulators (activators/inhibitors). In this review, we summarize the published data regarding the regulation of Notch family member degradation in breast cancer, while emphasizing areas that are likely to provide new therapeutic modalities for mechanism-based anti-cancer drugs. PMID:27263934

  9. Micro dynamics in mediation

    OpenAIRE

    Boserup, Hans

    2014-01-01

    The author has identified a number of styles in mediation, which lead to different processes and different outcomes. Through discourse and conversation analysis he examines the micro dynamics in three of these, the postmodern styles: systemic, transformative and narrative mediation. The differences between the three mediation ideologies and practice is illustrated through role play scripts enacted in each style. Mediator and providers of mediation and trainers in mediation are encouraged to a...

  10. Differential regulation of angiogenesis using degradable VEGF-binding microspheres.

    Science.gov (United States)

    Belair, David G; Miller, Michael J; Wang, Shoujian; Darjatmoko, Soesiawati R; Binder, Bernard Y K; Sheibani, Nader; Murphy, William L

    2016-07-01

    Vascular endothelial growth factor (VEGF) spatial and temporal activity must be tightly controlled during angiogenesis to form perfusable vasculature in a healing wound. The native extracellular matrix (ECM) regulates growth factor activity locally via sequestering, and researchers have used ECM-mimicking approaches to regulate the activity of VEGF in cell culture and in vivo. However, the impact of dynamic, affinity-mediated growth factor sequestering has not been explored in detail with biomaterials. Here, we sought to modulate VEGF activity dynamically over time using poly(ethylene glycol) microspheres containing VEGF-binding peptides (VBPs) and exhibiting varying degradation rates. The degradation rate of VBP microspheres conferred a differential ability to up- or down-regulate VEGF activity in culture with primary human endothelial cells. VBP microspheres with fast-degrading crosslinks reduced VEGF activity and signaling, while VBP microspheres with no inherent degradability sequestered and promoted VEGF activity in culture with endothelial cells. VBP microspheres with degradable crosslinks significantly reduced neovascularization in vivo, but neither non-degradable VBP microspheres nor bolus delivery of soluble VBP reduced neovascularization. The covalent incorporation of VBP to degradable microspheres was required to reduce neovascularization in a mouse model of choroidal neovascularization in vivo, which demonstrates a potential clinical application of degradable VBP microspheres to reduce pathological angiogenesis. The results herein highlight the ability to modulate the activity of a sequestered growth factor by changing the crosslinker identity within PEG hydrogel microspheres. The insights gained here may instruct the design and translation of affinity-based growth factor sequestering biomaterials for regenerative medicine applications. PMID:27061268

  11. Polycarbonate radiolytic degradation and stabilization

    International Nuclear Information System (INIS)

    Polycarbonate Durolon, useful for medical supplies fabrication, is submitted to gamma radiation for sterilization purposes. Scissions in main chain occur, in carbonyl groups, producing molecular degradations and yellowness. The radiolytic stabilization is obtained through additive to the polymer. In this work some degradation and stabilization aspects are presented. (L.C.J.A.). 7 refs, 7 figs, 2 tabs

  12. Degradation of polychlorinated biphenyls

    International Nuclear Information System (INIS)

    Polychlorinated biphenyls (PCB) are generally disposed of by incineration, an expensive and hazardous method. Moreover, in cases where the PCBs are a minor component of a nontoxic fluid, such as a dielectric fluid, incineration causes loss of the nontoxic fluid as well as the PCB. An alternative method for destroying PCBs is disclosed which is not only capable of detoxification of PCB-contaminated soils, sludges, and sediments, but can also remove PCBs from solution in a wide range of concentrations, permitting full recovery of the bulk of the solution free of PCBs. The process of the invention may be operated in a batch, continuous, or semicontinuous mode, and is advantageously used to detoxify organic liquids such as transformer oils. According to the invention, PCBs are chemically degraded by contact with a Lewis acid catalyst in a nonaqueous liquid medium, in the presence of a cation which combines with the chlorine on the PCB to form a solid chloride of the cation which will precipitate out from the liquid medium. Preferred Lewis acids are metal halides, particularly a combination of aluminum chloride and ferric chloride, and the preferred cation is potassium in the form of KOH. The Lewis acids may be supplied to the process by the adventitious corrosion of a vessel containing the PCB-contaminated matter. Experiments are described to illustrate the process of the invention. 3 figs

  13. Endopeptidase-Mediated Beta Lactam Tolerance

    OpenAIRE

    Dörr, Tobias; Davis, Brigid M.; Waldor, Matthew K.

    2015-01-01

    In many bacteria, inhibition of cell wall synthesis leads to cell death and lysis. The pathways and enzymes that mediate cell lysis after exposure to cell wall-acting antibiotics (e.g. beta lactams) are incompletely understood, but the activities of enzymes that degrade the cell wall (‘autolysins’) are thought to be critical. Here, we report that Vibrio cholerae, the cholera pathogen, is tolerant to antibiotics targeting cell wall synthesis. In response to a wide variety of cell wall- acting ...

  14. General Gaugino Mediation

    OpenAIRE

    Sudano, Matthew

    2010-01-01

    The spectrum of a class of gaugino mediation models with arbitrary hidden sector is considered. These models are defined by a diagonal breaking of the mediating gauge group, which places them outside the realm of General Gauge Mediation. While gauginos get masses as in ordinary gauge mediation, the scalar masses are screened.

  15. Redox Regulation of Insulin Degradation by Insulin-Degrading Enzyme

    OpenAIRE

    Cordes, Crystal M.; Bennett, Robert G.; Siford, Gerri L.; Hamel, Frederick G.

    2011-01-01

    Insulin-degrading enzyme (IDE) is a thiol sensitive peptidase that degrades insulin and amyloid β, and has been linked to type 2 diabetes mellitus and Alzheimer's disease. We examined the thiol sensitivity of IDE using S-nitrosoglutathione, reduced glutathione, and oxidized glutathione to distinguish the effects of nitric oxide from that of the redox state. The in vitro activity of IDE was studied using either partially purified cytosolic enzyme from male Sprague-Dawley rats, or purified rat ...

  16. Performance Degradation of LSCF Cathodes

    Energy Technology Data Exchange (ETDEWEB)

    Alinger, Matthew

    2013-09-30

    This final report summarizes the progress made during the October 1, 2008 - September 30, 2013 period under Cooperative Agreement DE-NT0004109 for the U. S. Department of Energy/National Energy Technology Laboratory (USDOE/NETL) entitled “Performance Degradation of LSCF Cathodes”. The primary objective of this program is to develop a performance degradation mitigation path for high performing, cost-effective solid oxide fuel cells (SOFCs). Strategies to mitigate performance degradation are developed and implemented. In addition, thermal spray manufacturing of SOFCs is explored. Combined, this work establishes a basis for cost-effective SOFC cells.

  17. Fibrin-mediated lentivirus gene transfer: implications for lentivirus microarrays

    OpenAIRE

    Raut, Shruti; Lei, Pedro; Padmashali, Roshan; Andreadis, Stelios T.

    2010-01-01

    We employed fibrin hydrogel as bioactive matrix for lentivirus mediated gene transfer. Fibrin-mediated gene transfer was highly efficient and exhibited strong dependence on fibrinogen concentration. Efficient gene transfer was achieved with fibrinogen concentration between 3.75 – 7.5 mg/mL. Lower fibrinogen concentrations resulted in diffusion of virus out of the gel while higher concentrations led to ineffective fibrin degradation by target cells. Addition of fibrinolytic inhibitors decrease...

  18. SiRNA Mediated Gene Silencing: A Mini Review

    OpenAIRE

    M.V Jeevitha; S.U Ajisha; Baby Joseph

    2012-01-01

    RNA interference (RNAi) technology has become a novel tool for silencing gene expression in cells or organisms. RNA interference is the process that double-stranded RNA induces the homology-dependent degradation of cognate mRNA mediated by 21-23 nucleotide short interfering RNA (siRNA). RNA interference is a powerful mechanism of gene silencing that underlies many aspects of eukaryotic biology. On the molecular level, RNAi is mediated by a family of ribonucleoprotein (RNP) complexes called R...

  19. Microbial ecology of bacterially mediated PCB biodegradation

    International Nuclear Information System (INIS)

    The roles of plasmid mediated and consortia mediated polychlorinated biphenyl (PCB) biodegradation by bacterial populations isolated from PCB contaminated freshwater sediments were investigated. PCB degrading bacteria were isolated by DNA:DNA colony hybridization, batch enrichments, and chemostat enrichment. Analysis of substrate removal and metabolite production were done using chlorinated biphenyl spray plates, reverse phase high pressure liquid chromatography, Cl- detection, and 14C-labeled substrate mineralization methods. A bacterial consortium, designated LPS10, involved in a concerted metabolic attack on chlorinated biphenyls, was shown to mineralize 4-chlorobiphenyl (4CB) and 4,4'-dichlorobiphenyl (4,4' CB). The LPS10 consortium was isolated by both batch and chemostat enrichment using 4CB and biphenyl (BP) as sole carbon source and was found to have tree bacterial isolates that predominated; these included: Pseudomonas, testosteroni LPS10A which mediated the breakdown of 4CB and 4,4' CB to the putative meta-cleavage product and subsequently to 4-chlorobenzoic acid (4CBA), an isolate tentatively identified as an Arthrobacter sp. LPS10B which mediated 4CBA degradation, and Pseudomonas putida by A LPS10C whose role in the consortium has not been determined

  20. Chitin Degradation In Marine Bacteria

    DEFF Research Database (Denmark)

    Paulsen, Sara; Machado, Henrique; Gram, Lone

    2015-01-01

    Introduction: Chitin is the most abundant polymer in the marine environment and the second most abundant in nature. Chitin does not accumulate on the ocean floor, because of microbial breakdown. Chitin degrading bacteria could have potential in the utilization of chitin as a renewable carbon and...... nitrogen source in the fermentation industry.Methods: Here, whole genome sequenced marine bacteria were screened for chitin degradation using phenotypic and in silico analyses.Results: The in silico analyses revealed the presence of three to nine chitinases in each strain, however the number of chitinases...... chitin regulatory system.Conclusions: This study has provided insight into the ecology of chitin degradation in marine bacteria. It also served as a basis for choosing a more efficient chitin degrading production strain e.g. for the use of chitin waste for large-scale fermentations....

  1. Ecosystemic approaches to land degradation

    International Nuclear Information System (INIS)

    Land degradation is recognized as the main outcome of desertification. However available procedures for its assessment are still unsatisfactory because are often too costly for surveying large areas and rely on specific components of the degradation process without being able to integrate them in a unique process. One of the objectives of De Survey project is designing and implementing operational procedures for desertification surveillance, including land degradation. A strategic report was compiled and reproduced here for selecting the most appropriate approaches to the project conditions. The report focuses on using attributes of ecosystem maturity as a natural way to integrate the different drivers of land degradation in simple indices. The review surveys different families of attributes concerned with water and energy fluxes through the ecosystem, its capacity to sustain biomass and net primary productivity, and its capacity to structure the space. Finally, some conclusions are presented about the choice criteria of the different approaches in the framne of operational applications. (Author) 20 refs.

  2. Ecosystemic approaches to land degradation

    Energy Technology Data Exchange (ETDEWEB)

    Puigdefabregas, J.; Barrio, G. del; Hill, J.

    2009-07-01

    Land degradation is recognized as the main outcome of desertification. However available procedures for its assessment are still unsatisfactory because are often too costly for surveying large areas and rely on specific components of the degradation process without being able to integrate them in a unique process. One of the objectives of De Survey project is designing and implementing operational procedures for desertification surveillance, including land degradation. A strategic report was compiled and reproduced here for selecting the most appropriate approaches to the project conditions. The report focuses on using attributes of ecosystem maturity as a natural way to integrate the different drivers of land degradation in simple indices. The review surveys different families of attributes concerned with water and energy fluxes through the ecosystem, its capacity to sustain biomass and net primary productivity, and its capacity to structure the space. Finally, some conclusions are presented about the choice criteria of the different approaches in the framne of operational applications. (Author) 20 refs.

  3. Degradation monitoring using probabilistic inference

    Science.gov (United States)

    Alpay, Bulent

    In order to increase safety and improve economy and performance in a nuclear power plant (NPP), the source and extent of component degradations should be identified before failures and breakdowns occur. It is also crucial for the next generation of NPPs, which are designed to have a long core life and high fuel burnup to have a degradation monitoring system in order to keep the reactor in a safe state, to meet the designed reactor core lifetime and to optimize the scheduled maintenance. Model-based methods are based on determining the inconsistencies between the actual and expected behavior of the plant, and use these inconsistencies for detection and diagnostics of degradations. By defining degradation as a random abrupt change from the nominal to a constant degraded state of a component, we employed nonlinear filtering techniques based on state/parameter estimation. We utilized a Bayesian recursive estimation formulation in the sequential probabilistic inference framework and constructed a hidden Markov model to represent a general physical system. By addressing the problem of a filter's inability to estimate an abrupt change, which is called the oblivious filter problem in nonlinear extensions of Kalman filtering, and the sample impoverishment problem in particle filtering, we developed techniques to modify filtering algorithms by utilizing additional data sources to improve the filter's response to this problem. We utilized a reliability degradation database that can be constructed from plant specific operational experience and test and maintenance reports to generate proposal densities for probable degradation modes. These are used in a multiple hypothesis testing algorithm. We then test samples drawn from these proposal densities with the particle filtering estimates based on the Bayesian recursive estimation formulation with the Metropolis Hastings algorithm, which is a well-known Markov chain Monte Carlo method (MCMC). This multiple hypothesis testing

  4. Degradation and resilience of soils

    OpenAIRE

    Lal, R.

    1997-01-01

    Debate on global soil degradation, its extent and agronomic impact, can only be resolved through understanding of the processes and factors leading to establishment of the cause-effect relationships for major soils, ecoregions, and land uses. Systematic evaluation through long-term experimentation is needed for establishing quantitative criteria of (i) soil quality in relation to specific functions; (ii) soil degradation in relation to critical limits of key soil properties and processes; and...

  5. Bacterial degradation of bile salts

    OpenAIRE

    Philipp, Bodo

    2011-01-01

    Bile salts are surface-active steroid compounds. Their main physiological function is aiding the digestion of lipophilic nutrients in intestinal tracts of vertebrates. Many bacteria are capable of transforming and degrading bile salts in the digestive tract and in the environment. Bacterial bile salt transformation and degradation is of high ecological relevance and also essential for the biotechnological production of steroid drugs. While biotechnological aspects have been reviewed many time...

  6. Some Misconceptions About Plastic Degradation

    OpenAIRE

    Raouf, Mohamed Imad N. Raouf

    1999-01-01

    In consistence with the importance of implementing best utilization of human resources towards maintaining suitable healthy environment for our next generations, concepts and fundamentals upon which most researches on degradation of plastics are based, as a solution of solid waste reduction, will be discussed. Proper understanding of plastic figures would better utilize human efforts toward useful tasks to control solid waste. Unfortunately, when plastics are made more degradable, they becom...

  7. Degradation of CIGS solar cells

    OpenAIRE

    Theelen, M.J.

    2015-01-01

    Large scale commercial introduction of CIGS photovoltaics (PV) requires modules with low costs, high efficiencies and long and predictable lifetimes. Unfortunately,knowledge about the lifetime of CIGS PV is limited, which is reflected in the results of field studies: degradation rates varying from 0% to about 4% per year have been observed. Since warrantees are given out that the modules will still yield 80% of their initial power after 20 years of field exposure, degradation rates are often ...

  8. Working session 1: Tubing degradation

    Energy Technology Data Exchange (ETDEWEB)

    Kharshafdjian, G. [Atomic Energy of Canada, Mississauga, Ontario (Canada); Turluer, G. [IPSN, Fontenay-aux-Roses (France)

    1997-02-01

    A general introductory overview of the purpose of the group and the general subject area of SG tubing degradation was given by the facilitator. The purpose of the session was described as to {open_quotes}develop conclusions and proposals on regulatory and technical needs required to deal with the issues of SG tubing degradation.{close_quotes} Types, locations and characteristics of tubing degradation in steam generators were briefly reviewed. The well-known synergistic effects of materials, environment, and stress and strain/strain rate, subsequently referred to by the acronym {open_quotes}MESS{close_quotes} by some of the group members, were noted. The element of time (i.e., evolution of these variables with time) was emphasized. It was also suggested that the group might want to consider the related topics of inspection capabilities, operational variables, degradation remedies, and validity of test data, and some background information in these areas was provided. The presentation given by Peter Millet during the Plenary Session was reviewed; Specifically, the chemical aspects and the degradation from the secondary side of the steam generator were noted. The main issues discussed during the October 1995 EPRI meeting on secondary side corrosion were reported, and a listing of the potential SG tube degradations was provided and discussed.

  9. Sonolytic degradation of 2-chlorobiphenyl

    Institute of Scientific and Technical Information of China (English)

    张光明; 华天星; 常爱敏

    2004-01-01

    The sonolytic degradation of 2-chlorobiphenyl was investigated. Mass spectroscopy was used to detect the products of sonolytic degradation of 2-chlorobiphenyl. The results show that the products of sonolytic degradation, such as biphenyl, ethyl benzene, diethylbiphenyl, dibutylbiphenyl, phenol, propylphenol and di-tert-butyl phenol are produced by thermolysis and hydroxyl free radical reactions, in which biphenyl counts for almost 40%(mole fraction) of the mother compound and others are at trace level. Rapid accumulation of chloride ion shows quick dechlorination, and 78% organic chlorine is converted into chloride ion. Free radical scavengers, bicarbonate and carbonate, decrease the reaction rate of sonolytic degradation of 2-chlorobiphenyl significantly, and the pseudo 1st order rate constant of sonolytic degradation of 2-chlorobiphenyl decreases linearly with the natural logarithm of the concentration of the added free radical scavenger, showing that the pyrolysis and hydroxyl free radical reaction are the two major pathways for the sonolytic degradation of 2-chlorobiphenyl, in which the hydroxyl radical concentration is estimated to be 1 × 10 10mol/L.

  10. Redox regulation of insulin degradation by insulin-degrading enzyme.

    Directory of Open Access Journals (Sweden)

    Crystal M Cordes

    Full Text Available Insulin-degrading enzyme (IDE is a thiol sensitive peptidase that degrades insulin and amyloid β, and has been linked to type 2 diabetes mellitus and Alzheimer's disease. We examined the thiol sensitivity of IDE using S-nitrosoglutathione, reduced glutathione, and oxidized glutathione to distinguish the effects of nitric oxide from that of the redox state. The in vitro activity of IDE was studied using either partially purified cytosolic enzyme from male Sprague-Dawley rats, or purified rat recombinant enzyme. We confirm that nitric oxide inhibits the degrading activity of IDE, and that it affects proteasome activity through this interaction with IDE, but does not affect the proteasome directly. Oxidized glutathione inhibits IDE through glutathionylation, which was reversible by dithiothreitol but not by ascorbic acid. Reduced glutathione had no effect on IDE, but reacted with partially degraded insulin to disrupt its disulfide bonds and accelerate its breakdown to trichloroacetic acid soluble fragments. Our results demonstrate the sensitivity of insulin degradation by IDE to the redox environment and suggest another mechanism by which the cell's oxidation state may contribute to the development of, and the link between, type 2 diabetes and Alzheimer's disease.

  11. Causal mediation analysis with a latent mediator.

    Science.gov (United States)

    Albert, Jeffrey M; Geng, Cuiyu; Nelson, Suchitra

    2016-05-01

    Health researchers are often interested in assessing the direct effect of a treatment or exposure on an outcome variable, as well as its indirect (or mediation) effect through an intermediate variable (or mediator). For an outcome following a nonlinear model, the mediation formula may be used to estimate causally interpretable mediation effects. This method, like others, assumes that the mediator is observed. However, as is common in structural equations modeling, we may wish to consider a latent (unobserved) mediator. We follow a potential outcomes framework and assume a generalized structural equations model (GSEM). We provide maximum-likelihood estimation of GSEM parameters using an approximate Monte Carlo EM algorithm, coupled with a mediation formula approach to estimate natural direct and indirect effects. The method relies on an untestable sequential ignorability assumption; we assess robustness to this assumption by adapting a recently proposed method for sensitivity analysis. Simulation studies show good properties of the proposed estimators in plausible scenarios. Our method is applied to a study of the effect of mother education on occurrence of adolescent dental caries, in which we examine possible mediation through latent oral health behavior. PMID:26363769

  12. Auxin-dependent compositional change in Mediator in ARF7- and ARF19-mediated transcription.

    Science.gov (United States)

    Ito, Jun; Fukaki, Hidehiro; Onoda, Makoto; Li, Lin; Li, Chuanyou; Tasaka, Masao; Furutani, Masahiko

    2016-06-01

    Mediator is a multiprotein complex that integrates the signals from transcription factors binding to the promoter and transmits them to achieve gene transcription. The subunits of Mediator complex reside in four modules: the head, middle, tail, and dissociable CDK8 kinase module (CKM). The head, middle, and tail modules form the core Mediator complex, and the association of CKM can modify the function of Mediator in transcription. Here, we show genetic and biochemical evidence that CKM-associated Mediator transmits auxin-dependent transcriptional repression in lateral root (LR) formation. The AUXIN/INDOLE 3-ACETIC ACID 14 (Aux/IAA14) transcriptional repressor inhibits the transcriptional activity of its binding partners AUXIN RESPONSE FACTOR 7 (ARF7) and ARF19 by making a complex with the CKM-associated Mediator. In addition, TOPLESS (TPL), a transcriptional corepressor, forms a bridge between IAA14 and the CKM component MED13 through the physical interaction. ChIP assays show that auxin induces the dissociation of MED13 but not the tail module component MED25 from the ARF7 binding region upstream of its target gene. These findings indicate that auxin-induced degradation of IAA14 changes the module composition of Mediator interacting with ARF7 and ARF19 in the upstream region of their target genes involved in LR formation. We suggest that this regulation leads to a quick switch of signal transmission from ARFs to target gene expression in response to auxin. PMID:27217573

  13. Compendium of photovoltaic degradation rates: Photovoltaic degradation rates

    Energy Technology Data Exchange (ETDEWEB)

    Jordan, Dirk C. [National Renewable Energy Laboratory (NREL), 15013 Denver West Parkway Golden CO 80401 USA; Kurtz, Sarah R. [National Renewable Energy Laboratory (NREL), 15013 Denver West Parkway Golden CO 80401 USA; VanSant, Kaitlyn [Colorado School of Mines, 1500 Illinois Street Golden CO 8040 USA; Newmiller, Jeff [DNV GL, 2420 Camino Ramon, Suite 300 San Ramon CA 95483 USA

    2016-02-07

    Published data on photovoltaic (PV) degradation measurements were aggregated and re-examined. The subject has seen an increased interest in recent years resulting in more than 11 000 degradation rates in almost 200 studies from 40 different countries. As studies have grown in number and size, we found an impact from sampling bias attributable to size and accuracy. Because of the correlational nature of this study we examined the data in several ways to minimize this bias. We found median degradation for x-Si technologies in the 0.5-0.6%/year range with the mean in the 0.8-0.9%/year range. Hetero-interface technology (HIT) and microcrystalline silicon (..mu..c-Si) technologies, although not as plentiful, exhibit degradation around 1%/year and resemble thin-film products more closely than x-Si. Several studies showing low degradation for copper indium gallium selenide (CIGS) have emerged. Higher degradation for cadmium telluride (CdTe) has been reported, but these findings could reflect a convolution of less accurate studies and longer stabilization periods for some products. Significant deviations for beginning-of-life measurements with respect to nameplate rating have been documented over the last 35 years. Therefore, degradation rates that use nameplate rating as reference may be significantly impacted. Studies that used nameplate rating as reference but used solar simulators showed less variation than similar studies using outdoor measurements, even when accounting for different climates. This could be associated with confounding effects of measurement uncertainty and soiling that take place outdoors. Hotter climates and mounting configurations that lead to sustained higher temperatures may lead to higher degradation in some, but not all, products. Wear-out non-linearities for the worst performing modules have been documented in a few select studies that took multiple measurements of an ensemble of modules during the lifetime of the system. However, the majority

  14. Shared mediated workspaces

    OpenAIRE

    Greef, Tjerk de; Gullström, Charlie; Handberg, Leif; Nefs, H.T.; Parnes, Peter

    2012-01-01

    Shared mediated spaces provide viable alternatives for meetings and interactions. The development of collaborative mediated workspaces and shared negotiation spaces will have a fundamental impact on all human practices. Previous design-led research, has identified spatial design concepts, such as mediated gaze, and spatial montage, which, if unaddressed, may be said to impose friction, and thus impact negatively on the experience of mediated presence. The current paper discusses a set of conc...

  15. Mediation and Conflict Management

    OpenAIRE

    Gerald Eisenkopf

    2009-01-01

    Mediation is a popular process to manage conflicts, but there is little systematic insight into its mechanisms. This paper discusses the results from an experiment in which a mediator can induce two conflict parties to behave cooperatively. If the mediator recommends cooperative behavior and threatens to punish deviations, she achieves the efficient solution. Similar results even obtain if the mediator is biased towards one party or has no incentive to prevent the conflict. Communication betw...

  16. Confidentiality of mediation communications

    OpenAIRE

    Koo, AKC

    2011-01-01

    Discusses the common law protection afforded to mediation negotiations by the without prejudice rule, legal professional privilege and the mediation agreement signed by all parties prior to the commencement of the mediation process. Examines the inclusion of admissions within the without prejudice rule, and the exceptions to the rule. Notes two pieces of legislation offering protection, namely the US Uniform Mediation Act 2001 and Directive 2008/52. Argues that the limited protection in the U...

  17. Bayesian Mediation Analysis

    OpenAIRE

    Yuan, Ying; MacKinnon, David P.

    2009-01-01

    This article proposes Bayesian analysis of mediation effects. Compared to conventional frequentist mediation analysis, the Bayesian approach has several advantages. First, it allows researchers to incorporate prior information into the mediation analysis, thus potentially improving the efficiency of estimates. Second, under the Bayesian mediation analysis, inference is straightforward and exact, which makes it appealing for studies with small samples. Third, the Bayesian approach is conceptua...

  18. Mediation as Signal

    OpenAIRE

    Holler, M.J.; Lindner, I.

    2004-01-01

    This paper analyzes mediation as a signal. Starting from a stylized case, a game theoretical model of one-sided incomplete information, taken from Cho and Kreps (1987), is applied to discuss strategic effects of mediation. It turns out that to reject mediation can be interpreted as a ”negative signal” while the interpretation of accepting or proposing mediation is ambiguous and does not necessarily change the prior beliefs of the uninformed party. This asymmetry suggests that, in equilibrium,...

  19. Mediators as Walrasian Auctioneers

    OpenAIRE

    Dickenson, David L.

    2004-01-01

    This article opens up mediation to systematic economic analysis by considering mediators as analogous.to the Walrasian auctioneers of exchange theory. By altering trade-off rates among bargaining issues, mediators facilitate a process leading towards Pareto efficient voluntary settlements.

  20. Hybrid Gauge Mediation

    OpenAIRE

    McGarrie, Moritz

    2011-01-01

    Inspired by four dimensional (de)constructions, we use the framework of "General gauge mediation in five dimensions" to interpolate between gaugino and ordinary gauge mediation. In particular we emphasise that an intermediate hybrid regime of mediation may be obtained in these higher dimensional models as has been obtained in the quiver gauge models.

  1. Bayesian Mediation Analysis

    Science.gov (United States)

    Yuan, Ying; MacKinnon, David P.

    2009-01-01

    In this article, we propose Bayesian analysis of mediation effects. Compared with conventional frequentist mediation analysis, the Bayesian approach has several advantages. First, it allows researchers to incorporate prior information into the mediation analysis, thus potentially improving the efficiency of estimates. Second, under the Bayesian…

  2. mediation: R Package for Causal Mediation Analysis

    Directory of Open Access Journals (Sweden)

    Dustin Tingley

    2014-09-01

    Full Text Available In this paper, we describe the R package mediation for conducting causal mediation analysis in applied empirical research. In many scientific disciplines, the goal of researchers is not only estimating causal effects of a treatment but also understanding the process in which the treatment causally affects the outcome. Causal mediation analysis is frequently used to assess potential causal mechanisms. The mediation package implements a comprehensive suite of statistical tools for conducting such an analysis. The package is organized into two distinct approaches. Using the model-based approach, researchers can estimate causal mediation effects and conduct sensitivity analysis under the standard research design. Furthermore, the design-based approach provides several analysis tools that are applicable under different experimental designs. This approach requires weaker assumptions than the model-based approach. We also implement a statistical method for dealing with multiple (causally dependent mediators, which are often encountered in practice. Finally, the package also offers a methodology for assessing causal mediation in the presence of treatment noncompliance, a common problem in randomized trials.

  3. Clad Degradation - FEPs Screening Arguments

    International Nuclear Information System (INIS)

    The purpose of this report is to document the screening of the cladding degradation features, events, and processes (FEPs) for commercial spent nuclear fuel (CSNF). This report also addresses the effect of some FEPs on both the cladding and the CSNF, DSNF, and HLW waste forms where it was considered appropriate to address the effects on both materials together. This report summarizes the work of others to screen clad degradation FEPs in a manner consistent with, and used in, the Total System Performance Assessment-License Application (TSPA-LA). This document was prepared according to ''Technical Work Plan for Waste Form Degradation Modeling, Testing, and Analyses in Support of LA'' (BSC 2004a [DIRS 167796])

  4. Clad Degradation - FEPs Screening Arguments

    Energy Technology Data Exchange (ETDEWEB)

    E. Siegmann

    2004-03-17

    The purpose of this report is to document the screening of the cladding degradation features, events, and processes (FEPs) for commercial spent nuclear fuel (CSNF). This report also addresses the effect of some FEPs on both the cladding and the CSNF, DSNF, and HLW waste forms where it was considered appropriate to address the effects on both materials together. This report summarizes the work of others to screen clad degradation FEPs in a manner consistent with, and used in, the Total System Performance Assessment-License Application (TSPA-LA). This document was prepared according to ''Technical Work Plan for Waste Form Degradation Modeling, Testing, and Analyses in Support of LA'' (BSC 2004a [DIRS 167796]).

  5. Radiation degradation of silk protein

    Energy Technology Data Exchange (ETDEWEB)

    Pewlong, W.; Sudatis, B. [Office of Atomic Energy for Peace, Bangkok (Thailand); Takeshita, Hidefumi; Yoshii, Fumio; Kume, Tamikazu [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment

    2000-03-01

    Silk fibroin fiber from the domesticated silkworm Bombyx mori was irradiated using an electron beam accelerator to investigate the application of the radiation degradation technique as a means to solubilize fibroin. The irradiation caused a significant degradation of the fiber. The tensile strength of fibroin fiber irradiated up to 2500 kGy decreased rapidly with increasing dose. The presence of oxygen in the irradiation atmosphere enhanced degradation of the tensile strength. The solubilization of irradiated fibroin fiber was evaluated using the following three kinds of solutions: a calcium chloride solution(CaCl{sub 2}/C{sub 2}H{sub 5}OH/H{sub 2}O=1:2:8 in mole ratio), a hydrochloric acid (0.5 N) and a distilled water. Dissolution of fibroin fiber into these solutions was significantly enhanced by irradiation. Especially, an appreciable amount of water soluble proteins was extracted by a distilled water. (author)

  6. Radiation degradation of silk protein

    International Nuclear Information System (INIS)

    Silk fibroin fiber from the domesticated silkworm Bombyx mori was irradiated using an electron beam accelerator to investigate the application of the radiation degradation technique as a means to solubilize fibroin. The irradiation caused a significant degradation of the fiber. The tensile strength of fibroin fiber irradiated up to 2500 kGy decreased rapidly with increasing dose. The presence of oxygen in the irradiation atmosphere enhanced degradation of the tensile strength. The solubilization of irradiated fibroin fiber was evaluated using the following three kinds of solutions: a calcium chloride solution(CaCl2/C2H5OH/H2O=1:2:8 in mole ratio), a hydrochloric acid (0.5 N) and a distilled water. Dissolution of fibroin fiber into these solutions was significantly enhanced by irradiation. Especially, an appreciable amount of water soluble proteins was extracted by a distilled water. (author)

  7. Aerobic degradation of BDE-209 by Enterococcus casseliflavus: Isolation, identification and cell changes during degradation process.

    Science.gov (United States)

    Tang, Shaoyu; Yin, Hua; Chen, Shuona; Peng, Hui; Chang, Jingjing; Liu, Zehua; Dang, Zhi

    2016-05-01

    Decabromodiphenyl ether (BDE-209) is one of the most commonly used brominated flame retardants that have contaminated the environment worldwide. Microbial bioremediation has been considered as an effective technique to remove these sorts of persistent organic pollutants. Enterococcus casseliflavus, a gram-positive bacterium capable of aerobically transforming BDE-209, was isolated by our team from sediments in Guiyu, an e-waste dismantling area in Guangdong Province, China. To promote microbial bioremediation of BDE-209 and elucidate the mechanism behind its aerobic degradation, the effects of BDE-209 on the cell changes of E. casseliflavus were examined in this study. The experimental results demonstrated that the high cell surface hydrophobicity (CSH) of E. casseliflavus made the bacteria absorb hydrophobic BDE-209 more easily. E. casseliflavus responded to BDE-209 stress, resulting in an increase in cell membrane permeability and accumulation of BDE-209 inside the cell. The differential expression of intracellular protein was analyzed through two-dimensional gel electrophoresis (2-DE). More than 50 differentially expressed protein spots were reproducibly detected, including 25 up, and 25 down regulated after a 4 days exposure. Moreover, the apoptotic-like cell changes were observed during E. casseliflavus mediated degradation of BDE-209 by means of flow cytometry. PMID:26852209

  8. Air pollutants degrade floral scents and increase insect foraging times

    Science.gov (United States)

    Fuentes, Jose D.; Chamecki, Marcelo; Roulston, T.'ai; Chen, Bicheng; Pratt, Kenneth R.

    2016-09-01

    Flowers emit mixtures of scents that mediate plant-insect interactions such as attracting insect pollinators. Because of their volatile nature, however, floral scents readily react with ozone, nitrate radical, and hydroxyl radical. The result of such reactions is the degradation and the chemical modification of scent plumes downwind of floral sources. Large Eddy Simulations (LES) are developed to investigate dispersion and chemical degradation and modification of floral scents due to reactions with ozone, hydroxyl radical, and nitrate radical within the atmospheric surface layer. Impacts on foraging insects are investigated by utilizing a random walk model to simulate insect search behavior. Results indicate that even moderate air pollutant levels (e.g., ozone mixing ratios greater than 60 parts per billion on a per volume basis, ppbv) substantially degrade floral volatiles and alter the chemical composition of released floral scents. As a result, insect success rates of locating plumes of floral scents were reduced and foraging times increased in polluted air masses due to considerable degradation and changes in the composition of floral scents. Results also indicate that plant-pollinator interactions could be sensitive to changes in floral scent composition, especially if insects are unable to adapt to the modified scentscape. The increase in foraging time could have severe cascading and pernicious impacts on the fitness of foraging insects by reducing the time devoted to other necessary tasks.

  9. The Science of Battery Degradation.

    Energy Technology Data Exchange (ETDEWEB)

    Sullivan, John P; Fenton, Kyle R [Sandia National Laboratories, Albuquerque, NM; El Gabaly Marquez, Farid; Harris, Charles Thomas [Sandia National Laboratories, Albuquerque, NM; Hayden, Carl C.; Hudak, Nicholas [Sandia National Laboratories, Albuquerque, NM; Jungjohann, Katherine Leigh [Sandia National Laboratories, Albuquerque, NM; Kliewer, Christopher Jesse; Leung, Kevin [Sandia National Laboratories, Albuquerque, NM; McDaniel, Anthony H.; Nagasubramanian, Ganesan [Sandia National Laboratories, Albuquerque, NM; Sugar, Joshua Daniel; Talin, Albert Alec; Tenney, Craig M [Sandia National Laboratories, Albuquerque, NM; Zavadil, Kevin R. [Sandia National Laboratories, Albuquerque, NM

    2015-01-01

    This report documents work that was performed under the Laboratory Directed Research and Development project, Science of Battery Degradation. The focus of this work was on the creation of new experimental and theoretical approaches to understand atomistic mechanisms of degradation in battery electrodes that result in loss of electrical energy storage capacity. Several unique approaches were developed during the course of the project, including the invention of a technique based on ultramicrotoming to cross-section commercial scale battery electrodes, the demonstration of scanning transmission x-ray microscopy (STXM) to probe lithium transport mechanisms within Li-ion battery electrodes, the creation of in-situ liquid cells to observe electrochemical reactions in real-time using both transmission electron microscopy (TEM) and STXM, the creation of an in-situ optical cell utilizing Raman spectroscopy and the application of the cell for analyzing redox flow batteries, the invention of an approach for performing ab initio simulation of electrochemical reactions under potential control and its application for the study of electrolyte degradation, and the development of an electrochemical entropy technique combined with x-ray based structural measurements for understanding origins of battery degradation. These approaches led to a number of scientific discoveries. Using STXM we learned that lithium iron phosphate battery cathodes display unexpected behavior during lithiation wherein lithium transport is controlled by nucleation of a lithiated phase, leading to high heterogeneity in lithium content at each particle and a surprising invariance of local current density with the overall electrode charging current. We discovered using in-situ transmission electron microscopy that there is a size limit to lithiation of silicon anode particles above which particle fracture controls electrode degradation. From electrochemical entropy measurements, we discovered that entropy

  10. Phenomenological Implications of Deflected Mirage Mediation: Comparison with Mirage Mediation

    OpenAIRE

    Altunkaynak, Baris; Everett, Lisa L.; Kim, Ian-Woo; Nelson, Brent D.; Rao, Yongyan

    2010-01-01

    We compare the collider phenomenology of mirage mediation and deflected mirage mediation, which are two recently proposed "mixed" supersymmetry breaking scenarios motivated from string compactifications. The scenarios differ in that deflected mirage mediation includes contributions from gauge mediation in addition to the contributions from gravity mediation and anomaly mediation also present in mirage mediation. The threshold effects from gauge mediation can drastically alter the low energy s...

  11. Endoplasmic Reticulum-Associated Degradation and Lipid Homeostasis.

    Science.gov (United States)

    Stevenson, Julian; Huang, Edmond Y; Olzmann, James A

    2016-07-17

    The endoplasmic reticulum is the port of entry for proteins into the secretory pathway and the site of synthesis for several important lipids, including cholesterol, triacylglycerol, and phospholipids. Protein production within the endoplasmic reticulum is tightly regulated by a cohort of resident machinery that coordinates the folding, modification, and deployment of secreted and integral membrane proteins. Proteins failing to attain their native conformation are degraded through the endoplasmic reticulum-associated degradation (ERAD) pathway via a series of tightly coupled steps: substrate recognition, dislocation, and ubiquitin-dependent proteasomal destruction. The same ERAD machinery also controls the flux through various metabolic pathways by coupling the turnover of metabolic enzymes to the levels of key metabolites. We review the current understanding and biological significance of ERAD-mediated regulation of lipid metabolism in mammalian cells. PMID:27296502

  12. Histone deacetylase 2 is phosphorylated, ubiquitinated, and degraded by cigarette smoke.

    Science.gov (United States)

    Adenuga, David; Yao, Hongwei; March, Thomas H; Seagrave, Jeanclare; Rahman, Irfan

    2009-04-01

    Cigarette smoke (CS)-induced lung inflammation involves the reduction of histone deacetylase 2 (HDAC2) abundance, which is associated with steroid resistance in patients with chronic obstructive pulmonary disease and in individuals with severe asthma who smoke cigarettes. However, the molecular mechanism of CS-mediated reduction of HDAC2 is not clearly known. We hypothesized that HDAC2 is phosphorylated and subsequently degraded by the proteasome in vitro in macrophages (MonoMac6), human bronchial and primary small airway epithelial cells, and in vivo in mouse lungs in response to chronic CS exposure. Cigarette smoke extract (CSE) exposure in MonoMac6 and in bronchial and airway epithelial cells led to phosphorylation of HDAC2 on serine/threonine residues by a protein kinase CK2-mediated mechanism, decreased HDAC2 activity, and increased ubiquitin-proteasome-dependent HDAC2 degradation. CK2 and proteasome inhibitors reversed CSE-mediated HDAC2 degradation, whereas serine/threonine phosphatase inhibitor, okadaic acid, caused phosphorylation and subsequent ubiquitination of HDAC2. CS-induced HDAC2 phosphorylation was detected in mouse lungs from 2 weeks to 4 months of CS exposure, and mice showed significantly lower lung HDAC2 levels. Thus, CS-mediated down-regulation of HDAC2 in human macrophages and lung epithelial cells in vitro and in mouse lung in vivo involves the induction of serine/threonine phosphorylation and proteasomal degradation, which may have implications for steroid resistance and abnormal inflammation caused by cigarette smoke. PMID:18927347

  13. Formaldehyde degradation by catalytic oxidation.

    OpenAIRE

    Shirey, W N; Hall, T. A.; Hanel, E; Sansone, E B

    1981-01-01

    Formaldehyde used for the disinfection of a laminar-flow biological safety cabinet was oxidatively degraded by using a catalyst. This technique reduced the formaldehyde concentration in the cabinet from about 5,000 to about 45 mg/m3 in 8 h. This technique should prove useful in other applications.

  14. Degradable polyethylene: fantasy or reality.

    Science.gov (United States)

    Roy, Prasun K; Hakkarainen, Minna; Varma, Indra K; Albertsson, Ann-Christine

    2011-05-15

    Plastic waste disposal is one of the serious environmental issues being tackled by our society today. Polyethylene, particularly in packaging films, has received criticism as it tends to accumulate over a period of time, leaving behind an undesirable visual footprint. Degradable polyethylene, which would enter the eco-cycle harmlessly through biodegradation would be a desirable solution to this problem. However, the "degradable polyethylene" which is presently being promoted as an environmentally friendly alternative to the nondegradable counterpart, does not seem to meet this criterion. This article reviews the state of the art on the aspect of degradability of polyethylene containing pro-oxidants, and more importantly the effect these polymers could have on the environment in the long run. On exposure to heat, light, and oxygen, these polymers disintegrate into small fragments, thereby reducing or increasing the visual presence. However, these fragments can remain in the environment for prolonged time periods. This article also outlines important questions, particularly in terms of time scale of complete degradation, environmental fate of the polymer residues, and possible accumulation of toxins, the answers to which need to be established prior to accepting these polymers as environmentally benign alternatives to their nondegradable equivalents. It appears from the existing literature that our search for biodegradable polyethylene has not yet been realized. PMID:21495645

  15. Methods of degrading napalm B

    Energy Technology Data Exchange (ETDEWEB)

    Tyndall, R.L.; Vass, A.

    1995-09-12

    Methods of degrading napalm and/or trinitrotoluene involve contacting the waste with specific intra-amoebic isolates of ATCC 40908 and/or dispersants derived therefrom. Useful isolates are deposited as ATCC 77529, NAP-1 deposited as ATCC 77526 and 13 deposited as ATCC 77527.

  16. Methods of degrading napalm B

    Science.gov (United States)

    Tyndall, Richard L.; Vass, Arpad

    1995-01-01

    Methods of degrading napalm and/or trinitrotoluene involve contacting the waste with specific intra-amoebic isolates of ATCC 40908 and/or dispersants derived therefrom. Useful isolates include is deposited as ATCC 77529, NAP-1 deposited as ATCC 77526 and 13 deposited as ATCC 77527.

  17. Polymeric Materials - introduction and degradation

    DEFF Research Database (Denmark)

    Kontogeorgis, Georgios

    1999-01-01

    These notes support the polymer part of the courses 91742 and 91762 (Materials and Corrosion/degradation of materials) taught in IFAKthey contain a short introduction on group contribution methods for estimating properties of polymers, polymer thermodynamics, viscoelasticity models as well as a...

  18. Photoelectrocatalytic degradation of Rose Bengal

    Institute of Scientific and Technical Information of China (English)

    LIU Hui-ling; ZHOU Ding; LI Xiang-zhong; YUE Ping-tao

    2003-01-01

    An innovative photoelectrode, TiO2/Ti mesh electrode, was prepared by galvanostaticanodisation. The morphology and the crystalline texture of the TiO2 film on mesh electrode were examined by scanning electronic microscopy and Raman spectroscopy respectively. The examination results indicated that the structure and properties of the film depended on anodisation rate, and the anatase was the dominant component under the controlled experimental conditions. Degradation of Rose Bengal(RB) in photocatalytic(PC) and photoelectrocatalytic(PEC) reaction was investigated, the results demonstrated that electric biasing could improve the efficiency of photocatalytic reaction. The measurement results of TOC in photoelectrocatalytic degradation showed that the mineralisation of RB was complete relatively. The comparison between the degradation efficiency of RB in PEC process and that in aqueous TiO2 dispersion was conducted. The results showed that the apparent first-order rate constant of RB degradation in PEC process was larger than that in aqueous dispersion with 0.1%-0.3% TiO2 powder, but was smaller than that in aqueous dispersion with 1.0% TiO2.

  19. Fatigue, degradation, and fracture 1990

    Energy Technology Data Exchange (ETDEWEB)

    Bamford, W.H. (Westinghouse Energy Systems (US)); Becht, C. IV (Becht Engineering Co., Inc. (US)); Bhandari, S. (Framatome (FR)); Gilman, J.D. (Electric Power Research Institute (US)); James, L.A. (Westinghouse Bettis Laboratory (US)); Prager, M. (Materials Properties Council (US))

    1990-01-01

    This book contains papers presented at the 1990 Pressure Vessels and Piping Conference. It is organized under the following headings: Environmental fatigue crack growth; Fatigue analysis and fracture assessment; Fatigue and fracture of piping; Fatigue and fracture of vessels; Degradation of ferritic, austenitic, and duplex stainless alloys in nuclear service.

  20. Bradykinin-mediated diseases.

    Science.gov (United States)

    Kaplan, Allen P

    2014-01-01

    Diseases which have been demonstrated to be caused by increased plasma levels of bradykinin all have angioedema as the common major clinical manifestation. Angioedema due to therapy with angiotensin-converting enzyme (ACE) inhibitors is caused by suppressed bradykinin degradation so that it accumulates. This occurs because ACE metabolizes bradykinin by removal of Phe-Arg from the C-terminus, which inactivates it. By contrast, angioedema due to C1 inhibitor deficiency (either hereditary types I and II, or acquired) is caused by bradykinin overproduction. C1 inhibitor inhibits factor XIIa, kallikrein and activity associated with the prekallikrein-HK (high-molecular-weight kininogen) complex. In its absence, uncontrolled activation of the plasma bradykinin cascade is seen once there has been an initiating stimulus. C4 levels are low in all types of C1 inhibitor deficiency due to the instability of C1 (C1r, in particular) such that some activated C1 always circulates and depletes C4. In the hereditary disorder, formation of factor XIIf (factor XII fragment) during attacks of swelling causes C4 levels to drop toward zero, and C2 levels decline. A kinin-like molecule, once thought to be a cleavage product derived from C2 that contributes to the increased vascular permeability seen in hereditary angioedema (HAE), is now thought to be an artifact, i.e. no such molecule is demonstrable. The acquired C1 inhibitor deficiency is associated with clonal disorders of B cell hyperreactivity, including lymphoma and monoclonal gammopathy. Most cases have an IgG autoantibody to C1 inhibitor which inactivates it so that the presentation is strikingly similar to type I HAE. New therapies for types I and II HAE include C1 inhibitor replacement therapy, ecallantide, a kallikrein antagonist, and icatibant, a B2 receptor antagonist. A newly described type III HAE has normal C1 inhibitor, although it is thought to be mediated by bradykinin, as is an antihistamine-resistant subpopulation of

  1. Autocrine signal transmission with extracellular ligand degradation

    International Nuclear Information System (INIS)

    Traveling waves of cell signaling in epithelial layers orchestrate a number of important processes in developing and adult tissues. These waves can be mediated by positive feedback autocrine loops, a mode of cell signaling where binding of a diffusible extracellular ligand to a cell surface receptor can lead to further ligand release. We formulate and analyze a biophysical model that accounts for ligand-induced ligand release, extracellular ligand diffusion and ligand–receptor interaction. We focus on the case when the main mode for ligand degradation is extracellular and analyze the problem with the sharp threshold positive feedback nonlinearity. We derive expressions that link the speed of propagation and other characteristics of traveling waves to the parameters of the biophysical processes, such as diffusion rates, receptor expression level, etc. Analyzing the derived expressions we found that traveling waves in such systems can exhibit a number of unusual properties, e.g. non-monotonic dependence of the speed of propagation on ligand diffusivity. Our results for the fully developed traveling fronts can be used to analyze wave initiation from localized perturbations, a scenario that frequently arises in the in vitro models of epithelial wound healing, and guide future modeling studies of cell communication in epithelial layers

  2. TMEM129 is a Derlin-1 associated ERAD E3 ligase essential for virus-induced degradation of MHC-I

    DEFF Research Database (Denmark)

    van den Boomen, Dick J H; Timms, Richard T; Grice, Guinevere L; Stagg, Helen R; Dougan, Gordon; Nathan, James A; Lehner, Paul J; Skjødt, Karsten

    2014-01-01

    The US11 gene product of human cytomegalovirus promotes viral immune evasion by hijacking the endoplasmic reticulum (ER)-associated degradation (ERAD) pathway. US11 initiates dislocation of newly translocated MHC I from the ER to the cytosol for proteasome-mediated degradation. Despite the critic...

  3. Bacterial degradation of recalcitrant PAHs: metabolic studies and application to pyrene degradation in a freshwater sediment

    Energy Technology Data Exchange (ETDEWEB)

    Jouanneau, Y.; Demaneche, S.; Meyer, Ch.; Willison, J.C. [CEA-Grenoble, UMR 5092 CNRS-CEA-UJF, 38 - Grenoble (France)

    2005-07-01

    Cost-effective bio-remediation strategies have been proposed to remove toxic chemicals, including polycyclic aromatic hydrocarbons (PAHs), from contaminated sites. However, the efficiency of these strategies is often limited, due to the resistance of certain chemicals to microbial degradation. Our studies deal with the biodegradation of four-ring PAHs using two recently isolated bacteria, Mycobacterium strain 6PY1, which can mineralize pyrene and phenanthrene, and Sphingomonas strain CHY-1, which mineralizes chrysene and various three-ring PAHs. The metabolic pathways for the biodegradation of PAHs have been investigated using GC-MS to identify and assay metabolites. Also, several enzymes involved in PAH catabolism have been identified by a combination of proteomic and genetic approaches. In Mycobacterium 6PY1, two ring-hydroxylating di-oxygenases which catalyze the initial attack of PAHs have been overproduced in E. coli, isolated and characterized. The selectivity of the two enzymes showed marked differences, since one di-oxygenase preferentially oxidized 2- or 3- ring PAHs whereas the other attacked pyrene and 3-ring PAHs exclusively. In Sphingomonas CHY-1, a single di-oxygenase, called PhnI, was found to convert seven PAHs, including chrysene, to the corresponding dihydro-diols. It is the first enzyme to be described which is able to attack the four-ring PAHs chrysene and benz[a]anthracene.. The fate of pyrene was examined in a sediment taken from a freshwater lake of the French Alps. Experiments were carried out in microcosms containing a layer of sediment which was spiked with {sup 14}C-pyrene. Pyrene mineralization was monitored over 61 days by measuring the {sup 14}CO{sub 2} evolved from the microcosms. Some microcosms were planted with young reeds (Phragmites australis), while other were inoculated with Mycobacterium 6PY1. P. australis reeds promoted a significant increase of pyrene degradation, which most likely resulted from a root-mediated increase of

  4. Bacterial degradation of recalcitrant PAHs: metabolic studies and application to pyrene degradation in a freshwater sediment

    International Nuclear Information System (INIS)

    Cost-effective bio-remediation strategies have been proposed to remove toxic chemicals, including polycyclic aromatic hydrocarbons (PAHs), from contaminated sites. However, the efficiency of these strategies is often limited, due to the resistance of certain chemicals to microbial degradation. Our studies deal with the biodegradation of four-ring PAHs using two recently isolated bacteria, Mycobacterium strain 6PY1, which can mineralize pyrene and phenanthrene, and Sphingomonas strain CHY-1, which mineralizes chrysene and various three-ring PAHs. The metabolic pathways for the biodegradation of PAHs have been investigated using GC-MS to identify and assay metabolites. Also, several enzymes involved in PAH catabolism have been identified by a combination of proteomic and genetic approaches. In Mycobacterium 6PY1, two ring-hydroxylating di-oxygenases which catalyze the initial attack of PAHs have been overproduced in E. coli, isolated and characterized. The selectivity of the two enzymes showed marked differences, since one di-oxygenase preferentially oxidized 2- or 3- ring PAHs whereas the other attacked pyrene and 3-ring PAHs exclusively. In Sphingomonas CHY-1, a single di-oxygenase, called PhnI, was found to convert seven PAHs, including chrysene, to the corresponding dihydro-diols. It is the first enzyme to be described which is able to attack the four-ring PAHs chrysene and benz[a]anthracene.. The fate of pyrene was examined in a sediment taken from a freshwater lake of the French Alps. Experiments were carried out in microcosms containing a layer of sediment which was spiked with 14C-pyrene. Pyrene mineralization was monitored over 61 days by measuring the 14CO2 evolved from the microcosms. Some microcosms were planted with young reeds (Phragmites australis), while other were inoculated with Mycobacterium 6PY1. P. australis reeds promoted a significant increase of pyrene degradation, which most likely resulted from a root-mediated increase of oxygen diffusion

  5. Degradation of monomethylhydrazine by two soil bacteria

    International Nuclear Information System (INIS)

    It has been reported that three heterotrophic soil bacteria had the capacity to degrade hydrazine. One of these organisms, Achromobacter sp., degraded hydrazine to N2 gas. Furthermore, it was reported that monomethylhydrazine (MMH) in Arredondo fine sand was mineralized to CO2, and that such degradation is microbial. However, microorganisms that degrade MMH have not been reported. MMH and hydrazine are chemically similar to one another. Therefore, this study was initiated to test the capacity of the two hydrazine-degrading bacteria, Achromobacter sp. and Pseudomonas sp., to degrade MMH

  6. Technology-Use Mediation

    DEFF Research Database (Denmark)

    Bansler, Jørgen P.; Havn, Erling C.

    This study analyzes how a group of ‘mediators’ in a large, multinational company adapted a computer-mediated communication technology (a ‘virtual workspace’) to the organizational context (and vice versa) by modifying features of the technology, providing ongoing support for users, and promoting...... appropriate conventions of use. Our findings corroborate earlier research on technology-use mediation, which suggests that such mediators can exert considerable influence on how a particular technology will be established and used in an organization. However, this study also indicates that the process of...... technology-use mediation is more complex and indeterminate than earlier literature suggests. In particular, we want to draw attention to the fact that advanced computer-mediated communication technologies are equivocal and that technology-use mediation consequently requires ongoing sensemaking (Weick 1995)....

  7. The Schizosaccharomyces pombe Mediator

    DEFF Research Database (Denmark)

    Venturi, Michela

    In the past several years great attention has been dedicated to the characterization of the Mediator complex in a different range of model organisms. Mediator is a conserved co-activator complex involved in transcriptional regulation and it conveys signals from regulatory transcription factors to...... the basal transcription machinery. Mediator was initially isolated from Saccharomyces cerevisiae based on its ability to render a RNA polymerase II in vitro transcription system responsive to activators. Additionally, structural studies have revealed striking structural similarities between S....... cerevisiae, Schizosaccharomyces pombe and mammalian Mediator. In our study, we have taken the S. pombe Mediator into consideration and characterized genetically and biochemically two subunits already know in S. cerevisiae, Med9 and Med11, but still not identified in the S. pombe Mediator. Genetic analysis...

  8. Technology-Use Mediation

    DEFF Research Database (Denmark)

    Bansler, Jørgen P.; Havn, Erling C.

    2003-01-01

    This study analyzes how a group of ‘mediators’ in a large, multinational company adapted a computer-mediated communication technology (a ‘virtual workspace’) to the organizational context (and vice versa) by modifying features of the technology, providing ongoing support for users, and promoting...... technology-use mediation is more complex and indeterminate than earlier literature suggests. In particular, we want to draw attention to the fact that advanced computer-mediated communication technologies are equivocal and that technology-use mediation consequently requires ongoing sensemaking (Weick 1995)....... appropriate conventions of use. Our findings corroborate earlier research on technology-use mediation, which suggests that such mediators can exert considerable influence on how a particular technology will be established and used in an organization. However, this study also indicates that the process of...

  9. Prospects for Mirage Mediation

    OpenAIRE

    Pierce, Aaron; Thaler, Jesse

    2006-01-01

    Mirage mediation reduces the fine-tuning in the minimal supersymmetric standard model by dynamically arranging a cancellation between anomaly-mediated and modulus-mediated supersymmetry breaking. We explore the conditions under which a mirage "messenger scale" is generated near the weak scale and the little hierarchy problem is solved. We do this by explicitly including the dynamics of the SUSY-breaking sector needed to cancel the cosmological constant. The most plausible scenario for generat...

  10. Immunologically mediated oral diseases

    OpenAIRE

    Sudha Jimson; Balachader, N.; N Anita; Babu, R

    2015-01-01

    Immune mediated diseases of oral cavity are uncommon. The lesions may be self-limiting and undergo remission spontaneously. Among the immune mediated oral lesions the most important are lichen planus, pemphigus, erythema multiformi, epidermolysis bullosa, systemic lupus erythematosis. Cellular and humoral mediated immunity play a major role directed against epithelial and connective tissue in chronic and recurrent patterns. Confirmatory diagnosis can be made by biopsy, direct and indirect imm...

  11. Lignin biodegradation with laccase-mediator systems

    Directory of Open Access Journals (Sweden)

    Lew Paul Christopher

    2014-03-01

    Full Text Available Lignin has a significant and largely unrealized potential as a source for the sustainable production of fuels and bulk high-value chemicals. It can replace fossil-based oil as a renewable feedstock that would bring about socio-economic and environmental benefits in our transition to a biobased economy. The efficient utilization of lignin however requires its depolymerization to low molecular weight phenolics and aromatics that can then serve as the building blocks for chemical syntheses of high-value products. The ability of laccase to attack and degrade lignin in conjunction with laccase mediators is currently viewed as one of the potential breakthrough applications for lignin valorization. Here we review the recent progress in lignin biodegradation with laccase-mediator systems, and research needs that need to be addressed in this field.

  12. Mediation in Romanian Legislation

    Directory of Open Access Journals (Sweden)

    Gianina Anemona Radu

    2012-05-01

    Full Text Available The complexity of the current social relations generates the necessity of developing and applyingnew methods of settling conflicts. Mediation can serve as an effective tool in resolving various conflictsincluding the criminal matters. This article gives a panoramic view on the application of the concept ofmediation and highlights the main features of mediation in criminal cases as they are reported to the nationallegislation and the legislation of Romania. Therefore the advantages of mediation and the opportunity toapply the latter in order to slave the conflicts caused by the commission of criminal offences are still beingdiscussed. The Romanian legislation and the Community rules establish the scope of expressly exemptedareas, the sides of freedom being the main principle, the mandatory dispositions being the exception. Fromthe contents of the Law 192/2006 result that mediation is exercisable in all areas with the condition that therights which make the subject of mediation could be used by the sides of the mediation. The mediation theoryanalyses the extrajudicial mediation and judicial mediation settlement.

  13. Microstructural degradation in compound tubes

    Energy Technology Data Exchange (ETDEWEB)

    Salonen, J.; Auerkari, P. [VTT Manufacturing Technology, Espoo (Finland)

    1996-12-31

    In order to quantify microstructural degradation at high temperatures, samples of SA 210 / AISI 304 L compound tube material were annealed in the temperature range 540-720 deg C for 1 to 1 000 hours. The hardness of the annealed material was measured and the micro structure of the samples was investigated with optical and scanning electron microscopy. Microstructural degradation was characterised by the carbide structure in the ferritic-pearlitic base material and by the depth of decarburised and carburised zones of the compound tube interface. The observed changes were quantified in terms of their time and temperature dependence and diffusion coefficients of the process. The results can be used in estimating the extent of thermal exposure of high-temperature components after long-term service or after incidences of overheating. (orig.) (4 refs.)

  14. Learner intuitions about energy degradation

    CERN Document Server

    Daane, Abigail R; Vokos, Stamatis

    2013-01-01

    A primary learning goal for energy in K-12 science instruction is that energy cannot be created or destroyed. However, learners' everyday ideas about energy often involve energy being "used up" or "wasted." In physics, the concept of energy degradation can connect those everyday ideas to the principle of energy conservation. Learners' spontaneous discussions of aspects of energy degradation and the second law of thermodynamics include ideas concerning the inaccessibility, usefulness and dispersion of energy. These ideas have motivated us to introduce new learning goals into our K-12 teacher professional development courses. We identify alignments between these learning goals and learners' informal ideas and discuss instructional implications created by these alignments. Our aim is to create stronger ties between formal physics knowledge and sociopolitical issues by making these learning goals a priority in our professional development.

  15. Advanced Oxidation Degradation of Diclofenac

    International Nuclear Information System (INIS)

    Advanced oxidation/reduction processes (AO/RPs), utilize free radical reactions to directly degrade chemical contaminants as an alternative to traditional water treatment. This study reports the absolute rate constants for reaction of diclofenac sodium and the model compound (2, 6-dichloraniline) with the two major AO/RP radicals; the hydroxyl radical (•OH) and hydrated electron (e-aq). The bimolecular reaction rate constants (M-1 s-1) for diclofenac for •OH was (9.29 ± 0.11) x 109, and, for e- aq was (1.53 ± 0.03) x109. Preliminary degradation mechanisms are suggested based on product analysis using 60Co γ-irradiation and LC-MS for reaction by-product identification. The toxicity of products was evaluated using the Vibrio fischeri luminescent bacteria method. (author)

  16. Identification of resin degradation product

    International Nuclear Information System (INIS)

    Strongly basic quaternary ammonium type anion exchangers employed for the purification of plutonium undergo thermal, radiolytic and chemical degradations to the delinking of quaternay ammonium type groups which form precipitates with tetravalent metal ions like Pu4+, Th4+, etc. A detailed investigation was carried out to understand the formation of the precipitates and their characteristics. Anion exchanger Dowex-1x4 was thermally degraded with 7-8 M HNO3 at about 80degC and the precipitate formed by the leach solution with thorium was subjected to analytical investigations. Based on the analytical data and other evidences a probable formula is assigned to the compound. (author). 9 refs., 2 tabs., 4 fi gs

  17. Strength Degradation of Gfrp Bars

    OpenAIRE

    Bhise, Vikrant Sudhakar

    2002-01-01

    The primary objective of this research was to examine the strength degradation of Glass Fiber Reinforced Polymer (GFRP) bars at high temperature and alkalinity and determine if an Arrhenius type relationship can be used as a means of projecting life. The work done includes a thorough literature review, experiments and development of strength prediction models. The experimental work involves exposure of GFRP bars incased in cement mortar to lime-water solution at 30, 45 and 57°C. Overall 100 ...

  18. Bacterial Degradation of Polychlorinated Biphenyls

    Czech Academy of Sciences Publication Activity Database

    Macková, M.; Uhlík, O.; Lovecká, P.; Viktorová, J.; Nováková, M.; Demnerová, K.; Sylvestre, M.; Macek, Tomáš

    Dordrecht: Springer, 2010 - (Barton, L.; Mandl, M.; Loy, A.), s. 347-366 ISBN 978-90-481-9203-8 Grant ostatní: GA ČR(CZ) GA525/09/1058; GA MŠk(CZ) 2B06156; GA MŠk(CZ) 2B08031 Institutional research plan: CEZ:AV0Z40550506 Keywords : bioremediation * PCB * anaerobic reductive dechlorination * aerobic degradation Subject RIV: EI - Biotechnology ; Bionics

  19. CHARACTERIZATION OF RUBBER DEGRADING ISOLATES

    Directory of Open Access Journals (Sweden)

    M. D. Chengalroyen

    2012-12-01

    Full Text Available Sixteen soil samples were screened for the presence of rubber degrading strains. Twenty-five strains displaying clear zone formation on latex agar plates were purified. Identification revealed that twenty three of these isolates were Streptomyces species, one Pseudonocardia species and one Methylibium species. The addition of carbon sources with the exception of tween 80 enhanced extracellular rubber biodegradation. Scanning electron microscopy revealed that the isolates were able to colonize and penetrate vulcanized glove rubber.

  20. CHARACTERIZATION OF RUBBER DEGRADING ISOLATES

    OpenAIRE

    M. D. Chengalroyen; Dabbs, E R

    2012-01-01

    Sixteen soil samples were screened for the presence of rubber degrading strains. Twenty-five strains displaying clear zone formation on latex agar plates were purified. Identification revealed that twenty three of these isolates were Streptomyces species, one Pseudonocardia species and one Methylibium species. The addition of carbon sources with the exception of tween 80 enhanced extracellular rubber biodegradation. Scanning electron microscopy revealed that the isolates were able to colonize...

  1. Degradation of Methyldopa by Banana

    OpenAIRE

    Kiminori Mohri; Yoshihiro Uesawa

    2010-01-01

    Methyldopa, an antihypertensive, is a very close analogue of DOPA. Drug interaction accompanied by degradation in a banana juice mixture was reported for DOPA. However, the effect of banana on methyldopa has not been reported. Therefore, we have investigated the impact of banana juice on methyldopa. The drug and supernatant of banana pulp were mixed, and the mixture was observed for changes in color, drug concentration, and ultraviolet-visible absorption spectra at 30 °C. The originally clear...

  2. PEM Degradation Investigation Final Technical Report

    Energy Technology Data Exchange (ETDEWEB)

    Dan Stevenson; Lee H Spangler

    2010-10-18

    This project conducted fundamental studies of PEM MEA degradation. Insights gained from these studies were disseminated to assist MEA manufacturers in understanding degradation mechanisms and work towards DOE 2010 fuel cell durability targets.

  3. Chlorophenol Degradation Coupled to Sulfate Reduction

    OpenAIRE

    Häggblom, M M; Young, L. Y.

    1991-01-01

    We studied chlorophenol degradation under sulfate-reducing conditions with an estuarine sediment inoculum. These cultures degraded 0.1 mM 2-, 3-, and 4-chlorophenol and 2,4-dichlorophenol within 120 to 220 days, but after refeeding with chlorophenols degradation took place in 40 days or less. Further refeeding greatly enhanced the rate of degradation. Sulfate consumption by the cultures corresponded to the stoichiometric values expected for complete oxidation of the chlorophenol to CO2. Forma...

  4. Degradation of Chlorophyll Luminescence in Plants

    International Nuclear Information System (INIS)

    The chlorophyll photoluminescence intensity degradation of Vallisneria spiralis L. water plant is studied. It is shown that the degradation curve is rather well described by a sum of two hyperbolic functions. The rate of intensity degradation reduces at low temperatures. At room temperature, a slow restoration of the luminescent system is observed after the irradiation has been ceased. No restoration is detected at the liquid nitrogen temperature. A simplified model which describes the luminescence degradation according to the quadratic law is suggested.

  5. Economics of land degradation in Eastern Africa

    OpenAIRE

    Kirui, Oliver Kiptoo; Mirzabaev, Alisher

    2014-01-01

    Land degradation remains a serious impediment to improving livelihoods in the Eastern Africa region. This working paper presents a general overview of the state and extent of land degradation in East Africa, explores its proximate and underlying drivers, identifies the land degradation hotspots in the region, and also discusses the productivity and poverty impacts of land degradation in the region. It is intended to serve as an exploratory tool for the ensuing more detailed quantitative analy...

  6. HRD1 and UBE2J1 target misfolded MHC class I heavy chains for endoplasmic reticulum-associated degradation

    OpenAIRE

    Burr, Marian L; Cano, Florencia; Svobodova, Stanislava; Boyle, Louise H; Boname, Jessica M.; Lehner, Paul J.

    2011-01-01

    The assembly of MHC class I molecules is governed by stringent endoplasmic reticulum (ER) quality control mechanisms. MHC class I heavy chains that fail to achieve their native conformation in complex with β2-microglobulin (β2m) and peptide are targeted for ER-associated degradation. This requires ubiquitination of the MHC class I heavy chain and its dislocation from the ER to the cytosol for proteasome-mediated degradation, although the cellular machinery involved in this process is unknown....

  7. Degradation analysis of thin film photovoltaic modules

    Energy Technology Data Exchange (ETDEWEB)

    Radue, C., E-mail: chantelle.radue@nmmu.ac.z [Department of Physics, PO Box 77000, Nelson Mandela Metropolitan University, Port Elizabeth 6031 (South Africa); Dyk, E.E. van [Department of Physics, PO Box 77000, Nelson Mandela Metropolitan University, Port Elizabeth 6031 (South Africa)

    2009-12-01

    Five thin film photovoltaic modules were deployed outdoors under open circuit conditions after a thorough indoor evaluation. Two technology types were investigated: amorphous silicon (a-Si:H) and copper indium gallium diselenide (CIGS). Two 14 W a-Si:H modules, labelled Si-1 and Si-2, were investigated. Both exhibited degradation, initially due to the well-known light-induced degradation described by Staebler and Wronski [Applied Physics Letters 31 (4) (1977) 292], and thereafter due to other degradation modes such as cell degradation. The various degradation modes contributing to the degradation of the a-Si:H modules will be discussed. The initial maximum power output (P{sub MAX}) of Si-1 was 9.92 W, with the initial light-induced degradation for Si-1 approx30% and a total degradation of approx42%. For Si-2 the initial P{sub MAX} was 7.93 W, with initial light-induced degradation of approx10% and a total degradation of approx17%. Three CIGS modules were investigated: two 20 W modules labelled CIGS-1 and CIGS-2, and a 40 W module labelled CIGS-3. CIGS-2 exhibited stable performance while CIGS-1 and CIGS-3 exhibited degradation. CIGS is known to be stable over long periods of time, and thus the possible reasons for the degradation of the two modules are discussed.

  8. Degradation analysis of thin film photovoltaic modules

    International Nuclear Information System (INIS)

    Five thin film photovoltaic modules were deployed outdoors under open circuit conditions after a thorough indoor evaluation. Two technology types were investigated: amorphous silicon (a-Si:H) and copper indium gallium diselenide (CIGS). Two 14 W a-Si:H modules, labelled Si-1 and Si-2, were investigated. Both exhibited degradation, initially due to the well-known light-induced degradation described by Staebler and Wronski [Applied Physics Letters 31 (4) (1977) 292], and thereafter due to other degradation modes such as cell degradation. The various degradation modes contributing to the degradation of the a-Si:H modules will be discussed. The initial maximum power output (PMAX) of Si-1 was 9.92 W, with the initial light-induced degradation for Si-1 ∼30% and a total degradation of ∼42%. For Si-2 the initial PMAX was 7.93 W, with initial light-induced degradation of ∼10% and a total degradation of ∼17%. Three CIGS modules were investigated: two 20 W modules labelled CIGS-1 and CIGS-2, and a 40 W module labelled CIGS-3. CIGS-2 exhibited stable performance while CIGS-1 and CIGS-3 exhibited degradation. CIGS is known to be stable over long periods of time, and thus the possible reasons for the degradation of the two modules are discussed.

  9. Polylactide Degradation by an Amycolatopsis sp

    OpenAIRE

    Pranamuda, H.; Tokiwa, Y.; Tanaka, H.

    1997-01-01

    By applying the plate count and clear-zone methods, it was confirmed that polylactide (PLA)-degrading microorganisms are sparsely distributed in soil environments. An Amycolatopsis isolate was successfully isolated. Microbial degradation of PLA film was demonstrated; i.e., about 60% of the 100-mg film initially added was degraded by the strain after 14 days of liquid culture.

  10. Teaching Mediated Public Relations.

    Science.gov (United States)

    Kent, Michael L.

    2001-01-01

    Discusses approaches to teaching a mediated public relations course, emphasizing the World Wide Web. Outlines five course objectives, assignments and activities, evaluation, texts, and lecture topics. Argues that students mastering these course objectives will understand ethical issues relating to media use, using mediated technology in public…

  11. Mediation and Domestic Violence

    Directory of Open Access Journals (Sweden)

    Jacques Faget

    2005-07-01

    Full Text Available This paper analyzes the potential and limits of recourse to mediation for regulating domestic violence. On the basis of an empirical study of its implementation in France and of the existing academic literature, it shows the existence of two types of practices reflecting two conceptions of mediation and more generally, two conceptions of the articulation between social and penal regulation

  12. Mediation and Domestic Violence

    OpenAIRE

    Jacques Faget

    2005-01-01

    This paper analyzes the potential and limits of recourse to mediation for regulating domestic violence. On the basis of an empirical study of its implementation in France and of the existing academic literature, it shows the existence of two types of practices reflecting two conceptions of mediation and more generally, two conceptions of the articulation between social and penal regulation

  13. Vacuole import and degradation pathway:Insights into a specialized autophagy pathway

    Institute of Scientific and Technical Information of China (English)

    Abbas; A; Alibhoy; Hui-Ling; Chiang

    2011-01-01

    Glucose deprivation induces the synthesis of pivotagluconeogenic enzymes such as fructose-1,6-bisphos-phatase, malate dehydrogenase, phosphoenolpyruvatecarboxykinase and isocitrate lyase in Saccharomycescerevisiae. However, following glucose replenishment,these gluconeogenic enzymes are inactivated and de-graded. Studies have characterized the mechanismsby which these enzymes are inactivated in response toglucose. The site of degradation of these proteins hasalso been ascertained to be dependent on the dura-tion of starvation. Glucose replenishment of short-termstarved cells results in these proteins being degradedin the proteasome. In contrast, addition of glucose tocells starved for a prolonged period results in theseproteins being degraded in the vacuole. In the vacuoledependent pathway, these proteins are sequestered inspecialized vesicles termed vacuole import and degra-dation (Vid). These vesicles converge with the endo-cytic pathway and deliver their cargo to the vacuolefor degradation. Recent studies have identified thatinternalization, as mediated by actin polymerization, isessential for delivery of cargo proteins to the vacuolefor degradation. In addition, components of the targetof rapamycin complex 1 interact with cargo proteins during glucose starvation. Furthermore, Tor1p dissoci-ates from cargo proteins following glucose replenish-ment. Future studies will be needed to elaborate on the importance of internalization at the plasma membrane and the subsequent import of cargo proteins into Vid vesicles in the vacuole dependent degradation pathway.

  14. Comparative metagenomic analysis of PAH degradation in soil by a mixed microbial consortium.

    Science.gov (United States)

    Zafra, German; Taylor, Todd D; Absalón, Angel E; Cortés-Espinosa, Diana V

    2016-11-15

    In this study, we used a taxonomic and functional metagenomic approach to analyze some of the effects (e.g. displacement, permanence, disappearance) produced between native microbiota and a previously constructed Polycyclic Aromatic Hydrocarbon (PAH)-degrading microbial consortium during the bioremediation process of a soil polluted with PAHs. Bioaugmentation with a fungal-bacterial consortium and biostimulation of native microbiota using corn stover as texturizer produced appreciable changes in the microbial diversity of polluted soils, shifting native microbial communities in favor of degrading specific populations. Functional metagenomics showed changes in gene abundance suggesting a bias towards aromatic hydrocarbon and intermediary degradation pathways, which greatly favored PAH mineralization. In contrast, pathways favoring the formation of toxic intermediates such as cytochrome P450-mediated reactions were found to be significantly reduced in bioaugmented soils. PAH biodegradation in soil using the microbial consortium was faster and reached higher degradation values (84% after 30 d) as a result of an increased co-metabolic degradation when compared with other mixed microbial consortia. The main differences between inoculated and non-inoculated soils were observed in aromatic ring-hydroxylating dioxygenases, laccase, protocatechuate, salicylate and benzoate-degrading enzyme genes. Based on our results, we propose that several concurrent metabolic pathways are taking place in soils during PAH degradation. PMID:27484946

  15. Effect of Aspergillus oryzae fermentation extract (Amaferm) on in vitro fiber degradation.

    Science.gov (United States)

    Beharka, A A; Nagaraja, T G

    1993-03-01

    The influence of Aspergillus oryzae fermentation extract (Amaferm) on in vitro fiber degradation was determined by incubating eight ground fibrous feed-stuffs with rumen fluid and buffer inoculum. Amaferm was added at 0, .4, .8, or 1.2 g/L of fermentation mixture. Both NDF and ADF degradabilities were determined after 96 h of incubation. Addition of extract had no effect on NDF or ADF degradability of pure cellulose, low endophyte fescue, wheat straw, corn silage, or prairie hay. Addition of Amaferm at .8 or 1.2 g/L increased NDF and ADF degradations of bromegrass hay and alfalfa hay; its addition at .4 or .8 g/L, but not at 1.2 g/L, increased NDF and ADF degradation of high endophyte fescue hay. In a second set of in vitro fermentations, selective antimicrobials (penicillin, streptomycin, and cycloheximide) were used to assess the influence of Amaferm on various microbial groups. The enhanced fiber degradation by Amaferm was attributed to its stimulation of bacterial activity because its addition to whole rumen fluid without or with cycloheximide increased fiber digestion. In contrast, addition of Amaferm to the whole rumen fluid plus penicillin and streptomycin treatment had no effect on fiber degradation, suggesting that fungal or protozoal activity was not affected by treatment. In conclusion, Amaferm increased fiber digestibility of certain feedstuffs, and the increase was mediated via stimulation of rumen bacterial, but not fungal or protozoal, activities. PMID:8385163

  16. Fungal degradation of coal as a pretreatment for methane production

    Science.gov (United States)

    Haider, Rizwan; Ghauri, Muhammad A.; SanFilipo, John R.; Jones, Elizabeth J.; Orem, William H.; Tatu, Calin A.; Akhtar, Kalsoom; Akhtar, Nasrin

    2013-01-01

    Coal conversion technologies can help in taking advantage of huge low rank coal reserves by converting those into alternative fuels like methane. In this regard, fungal degradation of coal can serve as a pretreatment step in order to make coal a suitable substrate for biological beneficiation. A fungal isolate MW1, identified as Penicillium chrysogenum on the basis of fungal ITS sequences, was isolated from a core sample of coal, taken from a well drilled by the US. Geological Survey in Montana, USA. The low rank coal samples, from major coal fields of Pakistan, were treated with MW1 for 7 days in the presence of 0.1% ammonium sulfate as nitrogen source and 0.1% glucose as a supplemental carbon source. Liquid extracts were analyzed through Excitation–Emission Matrix Spectroscopy (EEMS) to obtain qualitative estimates of solubilized coal; these analyses indicated the release of complex organic functionalities. In addition, GC–MS analysis of these extracts confirmed the presence of single ring aromatics, polyaromatic hydrocarbons (PAHs), aromatic nitrogen compounds and aliphatics. Subsequently, the released organics were subjected to a bioassay for the generation of methane which conferred the potential application of fungal degradation as pretreatment. Additionally, fungal-mediated degradation was also prospected for extracting some other chemical entities like humic acids from brown coals with high huminite content especially from Thar, the largest lignite reserve of Pakistan.

  17. Music, Radio, and Mediatization

    DEFF Research Database (Denmark)

    Krogh, Mads; Michelsen, Morten

    2016-01-01

    Mediatization has become a key concept for understanding the relations between media and other cultural and social fields. Contributing to the discussions related to the concept of mediatization, this article discusses how practices of radio and music(al life) influence each other. We follow Deacon......’s and Stanyer’s advice to supplement the concept of mediatization with ‘a series of additional concepts at lower levels of abstraction’ and suggest, in this respect, the notion of heterogeneous milieus of music– radio. Hereby, we turn away from the all-encompassing perspectives related to the concept of...... mediatization where media as such seem to be ascribed agency. Instead, we consider historical accounts of music–radio in order to address the complex non- linearity of concrete processes of mediatization as they take place in the multiple meetings between a decentred notion of radio and musical life....

  18. Function of ubiquitin (Ub) specific protease 15 (USP15) in HIV-1 replication and viral protein degradation.

    Science.gov (United States)

    Pyeon, Dohun; Timani, Khalid Amine; Gulraiz, Fahad; He, Johnny J; Park, In-Woo

    2016-09-01

    HIV-1 Nef is necessary and may be sufficient for HIV-1-associated AIDS pathogenicity, in that knockout of Nef alone can protect HIV-infected patients from AIDS. We therefore investigated the feasibility of physical knockout of Nef, using the host ubiquitin proteasome system in HIV-1-infected cells. Our co-immunoprecipitation analysis demonstrated that Nef interacted with ubiquitin specific protease 15 (USP15), and that USP15, which is known to stabilize cellular proteins, degraded Nef. Nef could also cause decay of USP15, although Nef-mediated degradation of USP15 was weaker than USP15-mediated Nef degradation. Direct interaction between Nef and USP15 was essential for the observed reciprocal decay of the proteins. Further, USP15 degraded not only Nef but also HIV-1 structural protein, Gag, thereby substantially inhibiting HIV-1 replication. However, Gag did not degrade USP15, indicating that the Nef and USP15 complex, in distinction to other viral proteins, play an integral role in coordinating viral protein degradation and hence HIV-1 replication. Moreover, Nef and USP15 globally suppressed ubiquitylation of cellular proteins, indicating that these proteins are major determinants for the stability of cellular as well as viral proteins. Taken together, these data indicate that Nef and USP15 are vital in regulating degradation of viral and cellular proteins and thus HIV-1 replication, and specific degradation of viral, not cellular proteins, by USP15 points to USP15 as a candidate therapeutic agent to combat AIDS by eliminating viral proteins from the infected cells via USP15-mediated proteosomal degradation. PMID:27460547

  19. Docetaxel induced-JNK2/PHD1 signaling pathway increases degradation of HIF-1α and causes cancer cell death under hypoxia

    Science.gov (United States)

    Oh, Eun-Taex; Kim, Chan Woo; Kim, Soo Jung; Lee, Jae-Seon; Hong, Soon-Sun; Park, Heon Joo

    2016-01-01

    HIF-1 (hypoxia-inducible factor-1) regulates the expression of more than 70 genes involved in angiogenesis, tumor growth, metastasis, chemoresistance, and radioresistance. Thus, there is growing interest in using HIF-1 inhibitors as anticancer drugs. Docetaxel, a Food and Drug Administration-approved anticancer drug, is reported to enhance HIF-1α degradation. Here, we investigated the molecular mechanism underlying docetaxel-induced HIF-1α degradation and cancer cell death under hypoxic conditions. Docetaxel pretreatment enhanced the polyubiquitination and proteasome-mediated degradation of HIF-1α, and increased cancer cell death under hypoxic conditions. Docetaxel also activated the prolyl hydroxylase, PHD1, in hypoxia, and pharmacological inhibition or siRNA-mediated knockdown of PHD1 prevented docetaxel-induced HIF-1α degradation and cancer cell death. Additionally, siRNA-mediated JNK2 knockdown blocked docetaxel-induced HIF-1α degradation and cancer cell death by inhibiting PHD1 activation. A luciferase reporter assay revealed that inhibition of the JNK2/PHD1 signaling pathway significantly increased the transcriptional activity of HIF-1 in docetaxel-treated cancer cells under hypoxia. Consistent with these results, docetaxel-treated JNK2-knockdown tumors grew much faster than control tumors through inhibition of docetaxel-induced PHD1 activation and degradation of HIF-1α. Our results collectively show that, under hypoxic conditions, docetaxel induces apoptotic cell death through JNK2/PHD1 signaling-mediated HIF-1α degradation. PMID:27263528

  20. ERK controls epithelial cell death receptor signalling and cellular FLICE-like inhibitory protein (c-FLIP) in ulcerative colitis

    DEFF Research Database (Denmark)

    Seidelin, Jakob Benedict; Coskun, Mehmet; Vainer, Ben;

    2013-01-01

    Intestinal epithelial cell (IEC) death signalling through the Fas receptor is impaired in active ulcerative colitis (UC). This is possibly due to the activation of cytoprotective pathways resulting in limitation of the tissue injury secondary to inflammation. We hypothesized that inflammatory sig...

  1. Monitoring Biopolymer Degradation by Taylor Dispersion Analysis.

    Science.gov (United States)

    Chamieh, Joseph; Biron, Jean Philippe; Cipelletti, Luca; Cottet, Hervé

    2015-12-14

    This work aims at demonstrating the interest of modern Taylor dispersion analysis (TDA), performed in narrow internal diameter capillary, for monitoring biopolymer degradations. Hydrolytic and enzymatic degradations of dendrigraft poly-l-lysine taken as model compounds have been performed and monitored by TDA at different degradation times. Different approaches for the data processing of the taylorgrams are compared, including simple integration of the taylorgram, curve fitting with a finite number of Gaussian peaks, cumulant-like method and Constrained Regularized Linear Inversion approach. Valuable information on the kinetics of the enzymatic/hydrolytic degradation reactions and on the degradation process can be obtained by TDA. PMID:26633075

  2. Degradation of Victoria Crater, Mars

    Science.gov (United States)

    Wilson, Sharon A.; Grant, John A.; Cohen, Barbara A.; Golombek, Mathew P.; Geissler, Paul E.; Sullivan, Robert J.; Kirk, Randolph L.; Parker, Timothy J.

    2008-01-01

    The $\\sim$750 m diameter and $\\sim$75 m deep Victoria crater in Meridiani Planum, Mars, presents evidence for significant degradation including a low, serrated, raised rim characterized by alternating alcoves and promontories, a surrounding low relief annulus, and a floor partially covered by dunes. The amount and processes of degradation responsible for the modified appearance of Victoria crater were evaluated using images obtained in situ by the Mars Exploration Rover Opportunity in concert with a digital elevation model created using orbital HiRISE images. Opportunity traversed along the north and northwest rim and annulus, but sufficiently characterized features visible in the DEM to enable detailed measurements of rim relief, ejecta thickness, and wall slopes around the entire degraded, primary impact structure. Victoria retains a 5 m raised rim consisting of 1-2 m of uplifted rocks overlain by 3 m of ejecta at the rim crest. The rim is $\\sim$120 to 220 m wide and is surrounded by a dark annulus reaching an average of 590 m beyond the raised rim. Comparison between observed morphology and that expected for pristine craters 500 to 750 m across indicate the original, pristine crater was close to 600 m in diameter. Hence, the crater has been erosionally widened by approximately 150 m and infilled by about 50 m of sediments. Eolian processes are responsible for modification at Victoria, but lesser contributions from mass wasting or other processes cannot be ruled out. Erosion by prevailing winds is most significant along the exposed rim and upper walls and accounts for $\\sim$50 m widening across a WNW-ESE diameter. The volume of material eroded from the crater walls and rim is $\\sim$20% less than the volume of sediments partially filling the crater, indicating eolian infilling from sources outside the crater over time. The annulus formed when $\\sim$1 m deflation of the ejecta created a lag of more resistant hematite spherules that trapped darker, regional

  3. Starch-degrading polysaccharide monooxygenases.

    Science.gov (United States)

    Vu, Van V; Marletta, Michael A

    2016-07-01

    Polysaccharide degradation by hydrolytic enzymes glycoside hydrolases (GHs) is well known. More recently, polysaccharide monooxygenases (PMOs, also known as lytic PMOs or LPMOs) were found to oxidatively degrade various polysaccharides via a copper-dependent hydroxylation. PMOs were previously thought to be either GHs or carbohydrate binding modules (CBMs), and have been re-classified in carbohydrate active enzymes (CAZY) database as auxiliary activity (AA) families. These enzymes include cellulose-active fungal PMOs (AA9, formerly GH61), chitin- and cellulose-active bacterial PMOs (AA10, formerly CBM33), and chitin-active fungal PMOs (AA11). These PMOs significantly boost the activity of GHs under industrially relevant conditions, and thus have great potential in the biomass-based biofuel industry. PMOs that act on starch are the latest PMOs discovered (AA13), which has expanded our perspectives in PMOs studies and starch degradation. Starch-active PMOs have many common structural features and biochemical properties of the PMO superfamily, yet differ from other PMO families in several important aspects. These differences likely correlate, at least in part, to the differences in primary and higher order structures of starch and cellulose, and chitin. In this review we will discuss the discovery, structural features, biochemical and biophysical properties, and possible biological functions of starch-active PMOs, as well as their potential application in the biofuel, food, and other starch-based industries. Important questions regarding various aspects of starch-active PMOs and possible economical driving force for their future studies will also be highlighted. PMID:27170366

  4. Managing livestock in degrading environments

    International Nuclear Information System (INIS)

    Degraded environments are both widespread (being found on all continents on earth) and diverse. They have been broadly classified as: irrigated (and rain-fed) farmland with elevated water tables causing salinity; rain-fed farmland with soil erosion, loss of organic matter, nutrient depletion and weed invasion; and degraded rangeland. This review considers all these but with a focus on the first two, and particularly addresses options for simultaneous improvement in livestock production and landscape health. There is evidence that responsible grazing is consistent with ecosystem benefits and resilient land use systems; exclusion from grazing may reduce diversity and create management complexity. Responsible grazing however will only prevail if the land owner or user receives a financial benefit in the process. Solutions need to be profitable. In the development and management of grazing systems, expectations need to be realistic. The prescriptive approach to livestock feeding based on the selection and cultivation of a small range of improved plant species to meet predetermined energy, protein and mineral requirements is inappropriate. Degraded landscapes are often associated with a high edaphic and climatic variability that is best suited to a diverse range of plant species in an assembly that will fluctuate over time and space. This diversity means that under some circumstances degraded land may contribute to reduced risk within a whole farm business. Simultaneous objectives for livestock and landscape improvement may or may not contribute to the return of the landscape to its original state. In some cases stable vegetation that provides some of the functional benefits of the original landscape, such as improved biodiversity and soil health, combined with production benefits is the best option available. This provides an opportunity to establish a range of objectives in vegetation management and design. In Australia, such an approach is leading to the development

  5. Managing livestock in degrading environments

    International Nuclear Information System (INIS)

    While overgrazing is often blamed for environmental degradation, there is clear evidence that livestock are not inherently damaging to rangelands or farming landscapes, and, in fact, may be required for their sustained health and profitability. Moderate to heavy grazing has, in some cases created highly resilient and ecologically sound systems while under-grazing has resulted in dense woody growth and reduced species diversity. Conversion of rangelands into intensive crop/fodder production has also led to progressive loss of diversity, species connectivity and ability to recover. Well-managed livestock in either a grassland or mixed crop/livestock system offer a highly efficient method of increasing the production of high quality food with minimal environmental impact. Although an ecological case can be established for the continued use of livestock in degrading landscapes, the reality is, livestock will only be grazed responsibly if the owner receives a benefit from the process. Importantly, by providing a potentially profitable option, the revegetation of degraded or partly degraded landscapes may take place through the expenditure of private rather than public funding. Given the vastness of the landscapes in question and the urban priorities in the expenditure of public funds, significant progress is only likely if profitable solutions are available. This use of livestock may or may not contribute to the return of the landscape to its original state. In some cases stable vegetation that provides some of the functional benefits of the original landscape, combined with the productive benefits of a profitable livestock system may be the best option available. This then provides an opportunity to design a landscape based on a range of predetermined objectives which include both profit and ecosystem services. For example, in Western Australia, the revegetation of 10% of the 1 million ha of saline land with halophytic shrubs and salt tolerant forage has resulted in a

  6. Cellular contractility requires ubiquitin mediated proteolysis.

    Directory of Open Access Journals (Sweden)

    Yuval Cinnamon

    Full Text Available BACKGROUND: Cellular contractility, essential for cell movement and proliferation, is regulated by microtubules, RhoA and actomyosin. The RhoA dependent kinase ROCK ensures the phosphorylation of the regulatory Myosin II Light Chain (MLC Ser19, thereby activating actomyosin contractions. Microtubules are upstream inhibitors of contractility and their depolymerization or depletion cause cells to contract by activating RhoA. How microtubule dynamics regulates RhoA remains, a major missing link in understanding contractility. PRINCIPAL FINDINGS: We observed that contractility is inhibited by microtubules not only, as previously reported, in adherent cells, but also in non-adhering interphase and mitotic cells. Strikingly we observed that contractility requires ubiquitin mediated proteolysis by a Cullin-RING ubiquitin ligase. Inhibition of proteolysis, ubiquitination and neddylation all led to complete cessation of contractility and considerably reduced MLC Ser19 phosphorylation. CONCLUSIONS: Our results imply that cells express a contractility inhibitor that is degraded by ubiquitin mediated proteolysis, either constitutively or in response to microtubule depolymerization. This degradation seems to depend on a Cullin-RING ubiquitin ligase and is required for cellular contractions.

  7. Using microorganisms to aid in hydrocarbon degradation

    International Nuclear Information System (INIS)

    Aliphatic hydrocarbons are threatening the potable water supply and the aquatic ecosystem. Given the right microbial inhabitant(s), a large portion of these aliphatic hydrocarbons could be biodegraded before reaching the water supply. The authors' purpose is to isolate possible oil-degrading organisms. Soil samples were taken from hydrocarbon-laden soils at petroleum terminals, a petroleum refinery waste-treatment facility, a sewage-treatment plant grease collector, a site of previous bioremediation, and various other places. Some isolates known to be good degraders were obtained from culture collection services. These samples were plated on a 10w-30 multigrade motor oil solid medium to screen for aliphatic hydrocarbon degraders. The degrading organisms were isolated, identified, and tested (CO2 evolution, BOD, and COD) to determine the most efficient degrader(s). Thirty-seven organisms were tested, and the most efficient degraders were Serratia marcescens, Escherichia coli, and Enterobacter agglomerans

  8. Using microorganisms to aid in hydrocarbon degradation

    Energy Technology Data Exchange (ETDEWEB)

    Black, W.; Zamora, J. (Middle Tennessee State Univ., Murfreesboro (United States))

    1993-04-01

    Aliphatic hydrocarbons are threatening the potable water supply and the aquatic ecosystem. Given the right microbial inhabitant(s), a large portion of these aliphatic hydrocarbons could be biodegraded before reaching the water supply. The authors' purpose is to isolate possible oil-degrading organisms. Soil samples were taken from hydrocarbon-laden soils at petroleum terminals, a petroleum refinery waste-treatment facility, a sewage-treatment plant grease collector, a site of previous bioremediation, and various other places. Some isolates known to be good degraders were obtained from culture collection services. These samples were plated on a 10w-30 multigrade motor oil solid medium to screen for aliphatic hydrocarbon degraders. The degrading organisms were isolated, identified, and tested (CO[sub 2] evolution, BOD, and COD) to determine the most efficient degrader(s). Thirty-seven organisms were tested, and the most efficient degraders were Serratia marcescens, Escherichia coli, and Enterobacter agglomerans.

  9. Enzymatic degradation of polycaprolactone-gelatin blend

    Science.gov (United States)

    Banerjee, Aditi; Chatterjee, Kaushik; Madras, Giridhar

    2015-04-01

    Blends of polycaprolactone (PCL), a synthetic polymer and gelatin, natural polymer offer a optimal combination of strength, water wettability and cytocompatibility for use as a resorbable biomaterial. The enzymatic degradation of PCL, gelatin and PCL-gelatin blended films was studied in the presence of lipase (Novozym 435, immobilized) and lysozyme. Novozym 435 degraded the PCL films whereas lysozyme degraded the gelatin. Though Novozym 435 and lysozyme individually could degrade PCL-gelatin blended films, the combination of these enzymes showed the highest degradation of these blended films. Moreover, the enzymatic degradation was much faster when fresh enzymes were added at regular intervals. The changes in physico-chemical properties of polymer films due to degradation were studied by scanning electron microscopy, Fourier transform infrared spectroscopy and differential scanning calorimetry. These results have important implications for designing resorbable biomedical implants.

  10. STRUCTURAL PERFORMANCE OF DEGRADED REINFORCED CONCRETE MEMBERS

    International Nuclear Information System (INIS)

    This paper describes the results of a study to evaluate, in probabilistic terms, the effects of age-related degradation on the structural performance of reinforced concrete members at nuclear power plants. The paper focuses on degradation of reinforced concrete flexural members and shear walls due to the loss of steel reinforcing area and loss of concrete area (cracking/spalling). Loss of steel area is typically caused by corrosion while cracking and spalling can be caused by corrosion of reinforcing steel, freeze-thaw, or aggressive chemical attack. Structural performance in the presence of uncertainties is depicted by a fragility (or conditional probability of failure). The effects of degradation on the fragility of reinforced concrete members are calculated to assess the potential significance of various levels of degradation. The fragility modeling procedures applied to degraded concrete members can be used to assess the effects of degradation on plant risk and can lead to the development of probability-based degradation acceptance limits

  11. Study of PP/montmorillonite composite degradation

    International Nuclear Information System (INIS)

    The objective of this work was to produce composites of PP/sodium bentonite and PP/ organophilic bentonite through melt intercalation and analyze the degradation produced by ultraviolet irradiation. The XRD results showed that the samples of nature bentonite had better interaction with de polymer and produced intercalated nanocomposite. The effect of UV irradiation on degradation was observed after 24 hours of exposition. The samples showed the same photoproducts and at the same proportion until 240 hours of UV exposition; with 480 hours the organophilize bentonite composite showed higher degradation than other ones. The superficial cracks increased with degradation time. The degradation occurs due chromophores impurities presented in the samples, thus samples with sodium clay show higher degradation, and organophilic clay contains ammonium salt that contribute to increase the degradation. (author)

  12. Single gene retrieval from thermally degraded DNA

    Indian Academy of Sciences (India)

    Lianwen Zhang; Lianwen Zhang

    2005-12-01

    To simulate single gene retrieval from ancient DNA, several related factors have been investigated. By monitoring a 889 bp polymerase chain reaction (PCR) product and genomic DNA degradation, we find that heat and oxygen (especially heat) are both crucial factors influencing DNA degradation. The heat influence, mainly represented by temperature and heating time, affects the DNA degradation via DNA depurination followed by cleavage of nearby phosphodiesters. The heating time influence is temperature-dependent. By reactive oxygen species (ROS) scavenging and 1,3-diphenyl-isobenzofuran (DPBF) bleaching experiments the influence of oxygen on DNA thermal degradation was shown to occur via a singlet oxygen pathway. A comparative study of the thermal degradation of cellular DNA and isolated DNA showed that cellular lipids can aggravate DNA thermal degradation. These results confirm the possibility of gene amplification from thermally degraded DNA. They can be used to evaluate the feasibility of the retrieval of single gene from ancient remains.

  13. The preferred route for the degradation of silencing target RNAs in transgenic plants depends on pre-established silencing conditions

    OpenAIRE

    Sanders, Matthew; Lannoo, Nausicaä; Maddelein, Wendy; Depicker, Anna; Van Montagu, Marc; Cornelissen, Marc; Jacobs, John

    2004-01-01

    RNA silencing can be initiated upon dsRNA accumulation and results in homology-dependent degradation of target RNAs mediated by 21–23 nt small interfering RNAs (siRNAs). These small regulatory RNAs can direct RNA degradation via different routes such as the RdRP/Dicer- and the RNA-induced silencing complex (RISC)-catalysed pathways. The relative contribution of both pathways to degradation of target RNAs is not understood. To gain further insight in the process of target selection and degrada...

  14. The Tissue Response and Degradation of Electrospun Poly(ε-caprolactone/Poly(trimethylene-carbonate Scaffold in Subcutaneous Space of Mice

    Directory of Open Access Journals (Sweden)

    Tao Jiang

    2014-01-01

    Full Text Available Due to the advantage of controllability on the mechanical property and the degradation rates, electrospun PCL/PTMC nanofibrous scaffold could be appropriate for vascular tissue engineering. However, the tissue response and degradation of electrospun PCL/PTMC scaffold in vivo have never been evaluated in detail. So, electrospun PCL/PTMC scaffolds with different blend ratios were prepared in this study. Mice subcutaneous implantation showed that the continuous degradation of PCL/PTMC scaffolds induced a lasted macrophage-mediated foreign body reaction, which could be in favor of the tissue regeneration in graft.

  15. Axionic Mirage Mediation

    International Nuclear Information System (INIS)

    In this talk, we propose a model of mirage mediation, in which Peccei-Quinn symmetry is incorporated. In this axionic mirage mediation, it is shown that the Peccei-Quinn symmetry breaking scale is dynamically determined around 1010 GeV to 1012 GeV due to the supersymmetry breaking effects. The problems in the original mirage mediation such as the μ-problem and the moduli problem can be solved simultaneouly. Furthermore, in our model the axino, which is the superpartner of the axion, is the lightest sparticle.

  16. Axionic Mirage Mediation

    CERN Document Server

    Nakamura, Shuntaro; Yamaguchi, Masahiro

    2008-01-01

    In this talk, we propose a model of mirage mediation, in which Peccei-Quinn symmetry is incorporated. In this \\textit{axionic mirage mediation}, it is shown that the Peccei-Quinn symmetry breaking scale is dynamically determined around $10^{10}$ GeV to $10^{12}$ GeV due to the supersymmetry breaking effects. The problems in the original mirage mediation such as the $\\mu$-problem and the moduli problem can be solved simultaneouly. Furthermore, in our model the axino, which is the superpartner of the axion, is the lightest sparticle.

  17. Prospects for mirage mediation

    International Nuclear Information System (INIS)

    Mirage mediation reduces the fine-tuning in the minimal supersymmetric standard model by dynamically arranging a cancellation between anomaly-mediated and modulus-mediated supersymmetry breaking. We explore the conditions under which a mirage 'messenger scale' is generated near the weak scale and the little hierarchy problem is solved. We do this by explicitly including the dynamics of the SUSY-breaking sector needed to cancel the cosmological constant. The most plausible scenario for generating a low mirage scale does not readily admit an extra-dimensional interpretation. We also review the possibilities for solving the μ/Bμ problem in such theories, a potential hidden source of fine-tuning

  18. Axionic Mirage Mediation

    OpenAIRE

    Nakamura, Shuntaro; Okumura, Ken-ichi; Yamaguchi, Masahiro

    2008-01-01

    In this talk, we propose a model of mirage mediation, in which Peccei-Quinn symmetry is incorporated. In this \\textit{axionic mirage mediation}, it is shown that the Peccei-Quinn symmetry breaking scale is dynamically determined around $10^{10}$ GeV to $10^{12}$ GeV due to the supersymmetry breaking effects. The problems in the original mirage mediation such as the $\\mu$-problem and the moduli problem can be solved simultaneouly. Furthermore, in our model the axino, which is the superpartner ...

  19. General resonance mediation

    Energy Technology Data Exchange (ETDEWEB)

    McGarrie, Moritz

    2012-07-15

    We extend the framework of general gauge mediation to cases where the mediating fields have a nontrivial spectral function, as might arise from strong dynamics. We demonstrate through examples that this setup describes a broad class of possible models of gauge mediated supersymmetry breaking. A main emphasis is to give general formulas for cross sections for {sigma}(visible {yields} hidden) in these resonance models. We will also give formulas for soft masses, A-terms and demonstrate the framework with a holographic setup.

  20. Gravity in gauge mediation

    International Nuclear Information System (INIS)

    We investigate O'Raifeartaigh-type models for F-term supersymmetry breaking in gauge mediation scenarios in the presence of gravity. It is pointed out that the vacuum structure of those models is such that in metastable vacua gravity mediation contribution to scalar masses is always suppressed to the level below 1 percent, almost sufficient for avoiding FCNC problem. Close to that limit, gravitino mass can be in the range 10-100 GeV, opening several interesting possibilities for gauge mediation models, including Giudice-Masiero mechanism for μ and Bμ generation. Gravity sector can include stabilized moduli.

  1. Environmental Degradation: Causes and Consequences

    Directory of Open Access Journals (Sweden)

    Swati Tyagi

    2014-08-01

    Full Text Available The subject of environmental economics is at the forefront of the green debate: the environment can no longer be viewed as an entity separate from the economy. Environmental degradation is of many types and have many consequences. To address this challenge a number of studies have been conducted in both developing and developed countries applying different methods to capture health benefits from improved environmental quality. Minimizing exposure to environmental risk factors by enhancing air quality and access to improved sources of drinking and bathing water, sanitation and clean energy is found to be associated with significant health benefits and can contribute significantly to the achievement of the Millennium Development Goals of environmental sustainability, health and development. In this paper, I describe the national and global causes and consequences of environmental degradation and social injustice. This paper provides a review of the literature on studies associated with reduced environmental risk and in particular focusing on reduced air pollution, enhanced water quality and climate change mitigation.

  2. Degradation of Acenaphthene by Ozone

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Objective To investigate the oxidation of acenaphthene (Ace), a polycyclic aromatic hydrocarbon (PAH) with a saturated C-C bond by ozone and to characterize the intermediate products of ozonation. Methods Ozone was generated from filtered dry oxygen by an ozone generator and continually bubbled into a reactor containing 1g/L Ace dissolved in an acetonitrile/water solvent mixture (90/10, v/v) at a rate of 0.5 mg/s. HPLC was used to analyze the Ace concentration. Total organic carbon (TOC) was used to measure the amount of water soluble organic compounds. GC-MS was used to identify the ozonized products. Oxygen uptake rate (OUR) of activated sludge was used to characterize the biodegradability of ozonized products. Results During the ozonation process, Ace was degraded, new organic compounds were produced and these intermediate products were difficult mineralize by ozone, with increasing TOC of soluble organics. The ozonized products were degraded by activated sludge more easily than Ace. Conclusion Ozonation decomposes the Ace and improves its biodegradability. The ozonation combined with biological treatment is probably an efficient and economical way to mineralize acenaphthene in wastewater.

  3. Phenomenological Implications of Deflected Mirage Mediation: Comparison with Mirage Mediation

    CERN Document Server

    Altunkaynak, Baris; Kim, Ian-Woo; Nelson, Brent D; Rao, Yongyan

    2010-01-01

    We compare the collider phenomenology of mirage mediation and deflected mirage mediation, which are two recently proposed "mixed" supersymmetry breaking scenarios motivated from string compactifications. The scenarios differ in that deflected mirage mediation includes contributions from gauge mediation in addition to the contributions from gravity mediation and anomaly mediation also present in mirage mediation. The threshold effects from gauge mediation can drastically alter the low energy spectrum from that of pure mirage mediation models, resulting in some cases in a squeezed gaugino spectrum and a gluino that is much lighter than other colored superpartners. We provide several benchmark deflected mirage mediation models and construct model lines as a function of the gauge mediation contributions, and discuss their discovery potential at the LHC.

  4. Mediator scolar - School Mediator (Romanian version)

    OpenAIRE

    Madalina CONSTANTIN

    2011-01-01

    The present article proposes to highlight the most important concepts with regard to school mediator. In this case we intend to add into discution the folowing: 1. Planning activities 2 Teamwork 3. Professional Development 4. PC Use 5. Communication 6. Solving conflicts 7. Developing school-community partnership 8. Counseling families / social groups disadvantaged on the role and importance of schooling 9. Implementation of inclusive practices 10. Overcoming emotional and behavioral difficult...

  5. XRN2 is required for the degradation of target RNAs by RNase H1-dependent antisense oligonucleotides

    International Nuclear Information System (INIS)

    Antisense oligonucleotides (ASOs) can suppress the expression of a target gene by cleaving pre-mRNA and/or mature mRNA via RNase H1. Following the initial endonucleolytic cleavage by RNase H1, the target RNAs are degraded by a mechanism that is poorly understood. To better understand this degradation pathway, we depleted the expression of two major 5′ to 3′ exoribonucleases (XRNs), named XRN1 and XRN2, and analyzed the levels of 3′ fragments of the target RNAs in vitro. We found that the 3′ fragments of target pre-mRNA generated by ASO were almost completely degraded from their 5′ ends by nuclear XRN2 after RNase H1-mediated cleavage, whereas the 3′ fragments of mature mRNA were partially degraded by XRN2. In contrast to ASO, small interference RNA (siRNA) could reduce the expression level of only mature mRNA, and the 3′ fragment was degraded by cytoplasmic XRN1. Our findings indicate that the RNAs targeted by RNase H1-dependent ASO are rapidly degraded in the nucleus, contrary to the cytoplasmic degradation pathway mediated by siRNA. - Highlights: • We compared the degradation mechanism of the transcript targeted by ASO and siRNA. • We focused on two 5′ to 3′ exoribonucleases, cytoplasmic XRN1, and nuclear XRN2. • The 3′ fragment of target pre-mRNA generated by ASO was degraded by XRN2. • The 3′ fragment of target mRNA generated by ASO was partially degraded by XRN2. • XRN1 depletion promoted accumulation of the 3′ fragment of mRNA generated by siRNA

  6. XRN2 is required for the degradation of target RNAs by RNase H1-dependent antisense oligonucleotides

    Energy Technology Data Exchange (ETDEWEB)

    Hori, Shin-Ichiro; Yamamoto, Tsuyoshi; Obika, Satoshi, E-mail: obika@phs.osaka-u.ac.jp

    2015-08-21

    Antisense oligonucleotides (ASOs) can suppress the expression of a target gene by cleaving pre-mRNA and/or mature mRNA via RNase H1. Following the initial endonucleolytic cleavage by RNase H1, the target RNAs are degraded by a mechanism that is poorly understood. To better understand this degradation pathway, we depleted the expression of two major 5′ to 3′ exoribonucleases (XRNs), named XRN1 and XRN2, and analyzed the levels of 3′ fragments of the target RNAs in vitro. We found that the 3′ fragments of target pre-mRNA generated by ASO were almost completely degraded from their 5′ ends by nuclear XRN2 after RNase H1-mediated cleavage, whereas the 3′ fragments of mature mRNA were partially degraded by XRN2. In contrast to ASO, small interference RNA (siRNA) could reduce the expression level of only mature mRNA, and the 3′ fragment was degraded by cytoplasmic XRN1. Our findings indicate that the RNAs targeted by RNase H1-dependent ASO are rapidly degraded in the nucleus, contrary to the cytoplasmic degradation pathway mediated by siRNA. - Highlights: • We compared the degradation mechanism of the transcript targeted by ASO and siRNA. • We focused on two 5′ to 3′ exoribonucleases, cytoplasmic XRN1, and nuclear XRN2. • The 3′ fragment of target pre-mRNA generated by ASO was degraded by XRN2. • The 3′ fragment of target mRNA generated by ASO was partially degraded by XRN2. • XRN1 depletion promoted accumulation of the 3′ fragment of mRNA generated by siRNA.

  7. Isolation and characterization of RDX-degrading Rhodococcus species from a contaminated aquifer.

    Science.gov (United States)

    Bernstein, Anat; Adar, Eilon; Nejidat, Ali; Ronen, Zeev

    2011-09-01

    Groundwater contamination by the explosive hexahydro-1,3,5-trinitro-1,3,5-triazine (RDX) is a global problem. Israel's coastal aquifer was contaminated with RDX. This aquifer is mostly aerobic and we therefore sought aerobic bacteria that might be involved in natural attenuation of the compound in the aquifer. RDX-degrading bacteria were captured by passively sampling the indigenous bacteria onto sterile sediments placed within sampling boreholes. Aerobic RDX biodegradation potential was detected in the sediments sampled from different locations along the plume. RDX degradation with the native sampled consortium was accompanied by 4-nitro-2,4-diazabutanal formation. Two bacterial strains of the genus Rhodococcus were isolated from the sediments and identified as aerobic RDX degraders. The xplA gene encoding the cytochrome P450 enzyme was partially (~500 bp) sequenced from both isolates. The obtained DNA sequences had 99% identity with corresponding gene fragments of previously isolated RDX-degrading Rhodococcus strains. RDX degradation by both strains was prevented by 200 μM of the cytochrome P450 inhibitor metyrapone, suggesting that cytochrome P450 indeed mediates the initial step in RDX degradation. RDX biodegradation activity by the T7 isolate was inhibited in the presence of nitrate or ammonium concentrations above 1.6 and 5.5 mM, respectively (100 mg l(-1)) while the T9N isolate's activity was retarded only by ammonium concentrations above 5.5 mM. This study shows that bacteria from the genus Rhodococcus, potentially degrade RDX in the saturated zone as well, following the same aerobic degradation pathway defined for other Rhodococcus species. RDX-degrading activity by the Rhodococcus species isolate T9N may have important implications for the bioremediation of nitrate-rich RDX-contaminated aquifers. PMID:21327803

  8. Drought, Mutualism Breakdown, and Landscape-Scale Degradation of Seagrass Beds.

    Science.gov (United States)

    de Fouw, Jimmy; Govers, Laura L; van de Koppel, Johan; van Belzen, Jim; Dorigo, Wouter; Sidi Cheikh, Mohammed A; Christianen, Marjolijn J A; van der Reijden, Karin J; van der Geest, Matthijs; Piersma, Theunis; Smolders, Alfons J P; Olff, Han; Lamers, Leon P M; van Gils, Jan A; van der Heide, Tjisse

    2016-04-25

    In many marine ecosystems, biodiversity critically depends on foundation species such as corals and seagrasses that engage in mutualistic interactions [1-3]. Concerns grow that environmental disruption of marine mutualisms exacerbates ecosystem degradation, with breakdown of the obligate coral mutualism ("coral bleaching") being an iconic example [2, 4, 5]. However, as these mutualisms are mostly facultative rather than obligate, it remains unclear whether mutualism breakdown is a common risk in marine ecosystems, and thus a potential accelerator of ecosystem degradation. Here, we provide evidence that drought triggered landscape-scale seagrass degradation and show the consequent failure of a facultative mutualistic feedback between seagrass and sulfide-consuming lucinid bivalves that in turn appeared to exacerbate the observed collapse. Local climate and remote sensing analyses revealed seagrass collapse after a summer with intense low-tide drought stress. Potential analysis-a novel approach to detect feedback-mediated state shifts-revealed two attractors (healthy and degraded states) during the collapse, suggesting that the drought disrupted internal feedbacks to cause abrupt, patch-wise degradation. Field measurements comparing degraded patches that were healthy before the collapse with patches that remained healthy demonstrated that bivalves declined dramatically in degrading patches with associated high sediment sulfide concentrations, confirming the breakdown of the mutualistic seagrass-lucinid feedback. Our findings indicate that drought triggered mutualism breakdown, resulting in toxic sulfide concentrations that aggravated seagrass degradation. We conclude that external disturbances can cause sudden breakdown of facultative marine mutualistic feedbacks. As this may amplify ecosystem degradation, we suggest including mutualisms in marine conservation and restoration approaches. PMID:26972316

  9. Water Vapor-Mediated Volatilization of High-Temperature Materials

    Science.gov (United States)

    Meschter, Peter J.; Opila, Elizabeth J.; Jacobson, Nathan S.

    2013-07-01

    Volatilization in water vapor-containing atmospheres is an important and often unexpected mechanism of degradation of high-temperature materials during processing and in service. Thermodynamic properties data sets for key (oxy)hydroxide vapor product species that are responsible for material transport and damage are often uncertain or unavailable. Estimation, quantum chemistry calculation, and measurement methods for thermodynamic properties of these species are reviewed, and data judged to be reliable are tabulated and referenced. Applications of water vapor-mediated volatilization include component and coating recession in turbine engines, oxidation/volatilization of ferritic steels in steam boilers, chromium poisoning in solid-oxide fuel cells, vanadium transport in hot corrosion and degradation of hydrocracking catalysts, Na loss from Na β"-Al2O3 tubes, and environmental release of radioactive isotopes in a nuclear reactor accident or waste incineration. The significance of water vapor-mediated volatilization in these applications is described.

  10. Technology-Use Mediation

    DEFF Research Database (Denmark)

    Bansler, Jørgen P.; Havn, Erling C.

    2004-01-01

    deepens our understanding of how organizations appropriate new electronic communication media. The paper analyzes how a group of mediators in a large, multinational company adapted a new web-based CMC technology (a virtual workspace) to the local organizational context (and vice versa) by modifying...... features of the technology, providing ongoing support for users, and promoting appropriate conventions of use. We found that these mediators exerted considerable influence on how the technology was established and used in the organization. The mediators were not neutral facilitators of a well......Implementation of new computer-mediated communication (CMC) systems in organizations is a complex socio-technical endeavour, involving the mutual adaptation of technology and organization over time. Drawing on the analytic concept of sensemaking, this paper provides a theoretical perspective that...

  11. Technology-Use Mediation

    DEFF Research Database (Denmark)

    Bansler, Jørgen P.; Havn, Erling C.

    2004-01-01

    Implementation of new computer-mediated communication (CMC) systems in organizations is a complex socio-technical endeavour, involving the mutual adaptation of technology and organization over time. Drawing on the analytic concept of sensemaking, this paper provides a theoretical perspective that...... deepens our understanding of how organizations appropriate new electronic communication media. The paper analyzes how a group of mediators in a large, multinational company adapted a new web-based CMC technology (a virtual workspace) to the local organizational context (and vice versa) by modifying...... features of the technology, providing ongoing support for users, and promoting appropriate conventions of use. We found that these mediators exerted considerable influence on how the technology was established and used in the organization. The mediators were not neutral facilitators of a well...

  12. Inflammatory mediators in osteoarthritis

    OpenAIRE

    M Beekhuizen

    2014-01-01

    Osteoarthritis (OA) is a degenerative joint disorder involving cartilage destruction and joint inflammation. Despite extensive research, still much is unknown on the pathogenesis and aetiology of OA. Inflammation and inflammatory mediators (both local and systemic) are key in the pathogenesis of OA. For rheumatoid arthritis, multiple therapies are based on targeting the mediators that are associated with inflammation and joint destruction. Motivated by these findings we set off to identify wh...

  13. Interactive Mediated Reality

    OpenAIRE

    Grasset, Raphaël; Boissieux, Laurence; Gascuel, Jean-Dominique; Schmalstieg, Dieter

    2005-01-01

    International audience Mediated reality describes the concept of filtering our vision of reality, typically using a head-mounted video mixing display. We can redefine this idea in a more constructive context, applying dynamic changes to the appearance and geometry of objects in a real scene using computer graphics. In this paper, we propose new tools for interactively mediated reality. After describing a new generic framework for achieving this goal, we present a prototype system for paint...

  14. Chronic alloantibody mediated rejection

    OpenAIRE

    Smith, R. Neal; Colvin, Robert B.

    2011-01-01

    Alloantibodies clearly cause acute antibody mediated rejection, and all available evidence supports their pathogenic etiology in the development of chronic alloantibody mediated rejection (CAMR). But the slow evolution of this disease, the on-going immunosuppression, the variations in titer of alloantibodies, and variation in antigenic targets all complicate identifying which dynamic factors are most important clinically and pathologically. This review highlights the pathological factors rela...

  15. Mechanisms of p53-mediated mitochondrial membrane permeabilization

    Institute of Scientific and Technical Information of China (English)

    Eugenia Morselli; Lorenzo Galluzzi; Guido Kroemer

    2008-01-01

    @@ The p53 protein is mutated or inactivated in more than 50% of human cancers, underscoring its cardinal importance as an oncosuppressor, p53 is expressed in all nucleated cells and can be activated by a plethora of post-transcriptional modifications (in particular by the phosphorylation of critical serine residues), as well as by the inhibition of its degradation (mainly mediated by the E3 ubiquitin ligase MDM2).

  16. E-beam degradation of dibutyl phthalate

    International Nuclear Information System (INIS)

    E-beam degradation of dibutyl phthalate (DBP) in oxidation system (acetonitrile/water), reduction system (methanol/water, t-BuOH/water), and pure water systems was investigated. DBP concentration in the four solutions was determined by HPLC, and the degradation products were analyzed by GC/MS. The results showed that the DBP degradation followed pseudo-first-order kinetics. DBP in a concentration of 7.8mg/L, in all solutions but the t-BuOH/water, could be degraded in a rate of over 85% by 0.5 kGy E-beam irradiation. The degradation products included diethyl phthalate, bis(2-methylpropyl)ester, and 1,2-Benzenedicarboxylic acid in the three solutions. Finally, mechanism of the DBP degradation was discussed. (authors)

  17. The Degraded Poisson Wiretap Channel

    CERN Document Server

    Laourine, Amine

    2010-01-01

    Providing security guarantees for wireless communication is critically important for today's applications. While previous work in this area has concentrated on radio frequency (RF) channels, providing security guarantees for RF channels is inherently difficult because they are prone to rapid variations due small scale fading. Wireless optical communication, on the other hand, is inherently more secure than RF communication due to the intrinsic aspects of the signal propagation in the optical and near-optical frequency range. In this paper, secure communication over wireless optical links is examined by studying the secrecy capacity of a direct detection system. For the degraded Poisson wiretap channel, a closed-form expression of the secrecy capacity is given. A complete characterization of the general rate-equivocation region is also presented. For achievability, an optimal code is explicitly constructed by using the structured code designed by Wyner for the Poisson channel. The converse is proved in two dif...

  18. Protein degradation and iron homeostasis.

    Science.gov (United States)

    Thompson, Joel W; Bruick, Richard K

    2012-09-01

    Regulation of both systemic and cellular iron homeostasis requires the capacity to sense iron levels and appropriately modify the expression of iron metabolism genes. These responses are coordinated through the efforts of several key regulatory factors including F-box and Leucine-rich Repeat Protein 5 (FBXL5), Iron Regulatory Proteins (IRPs), Hypoxia Inducible Factor (HIF), and ferroportin. Notably, the stability of each of these proteins is regulated in response to iron. Recent discoveries have greatly advanced our understanding of the molecular mechanisms governing iron-sensing and protein degradation within these pathways. It has become clear that iron's privileged roles in both enzyme catalysis and protein structure contribute to its regulation of protein stability. Moreover, these multiple pathways intersect with one another in larger regulatory networks to maintain iron homeostasis. This article is part of a Special Issue entitled: Cell Biology of Metals. PMID:22349011

  19. Degradation of Endeavour Crater, Mars

    Science.gov (United States)

    Grant, J. A.; Crumpler, L. S.; Parker, T. J.; Golombek, M. P.; Wilson, S. A.; Mittlefehldt, D. W.

    2015-01-01

    The Opportunity rover has traversed portions of two western rim segments of Endeavour, a 22 km-diameter crater in Meridiani Planum, for the past three years. The resultant data enables the evaluation of the geologic expression and degradation state of the crater. Endeavour is Noa-chian-aged, complex in morphology, and originally may have appeared broadly similar to the more pristine 20.5 km-diameter Santa Fe complex crater in Lunae Palus (19.5degN, 312.0degE). By contrast, Endeavour is considerably subdued and largely buried by younger sulfate-rich plains. Exposed rim segments dubbed Cape York (CY) and Solander Point/Murray Ridge/Pillinger Point (MR) located approximately1500 m to the south reveal breccias interpreted as remnants of the ejecta deposit, dubbed the Shoemaker Formation. At CY, the Shoemaker Formation overlies the pre-impact rocks, dubbed the Matijevic Formation.

  20. Controlled enzyme catalyzed heteropolysaccharide degradation

    DEFF Research Database (Denmark)

    Rasmussen, Louise Enggaard

    The work presented in this PhD thesis has provided a better understanding of the enzyme kinetics and quantitative phenomena of the hydrolysis of xylan substrates by selected pure enzyme preparations. Furthermore, the options for producing specific substituted xylooligosaccharides from selected...... substrates by specific xylanase treatment have been examined. The kinetics of the enzymatic degradation of water-extractable wheat arabinoxylan (WE-AX) during designed treatments with selected monocomponent enzymes was investigated by monitoring the release of xylose and arabinose. The results of different...... effects between -xylosidase and the α-L-arabinofuranosidases on the xylose release were low as compared to the effect of xylanase addition with β-xylosidase, which increased the xylose release by ~25 times in 30 minutes. At equimolar addition levels of the four enzymes, the xylanase activity was thus rate...

  1. Bacterial Degradation of Aromatic Compounds

    Directory of Open Access Journals (Sweden)

    Qing X. Li

    2009-01-01

    Full Text Available Aromatic compounds are among the most prevalent and persistent pollutants in the environment. Petroleum-contaminated soil and sediment commonly contain a mixture of polycyclic aromatic hydrocarbons (PAHs and heterocyclic aromatics. Aromatics derived from industrial activities often have functional groups such as alkyls, halogens and nitro groups. Biodegradation is a major mechanism of removal of organic pollutants from a contaminated site. This review focuses on bacterial degradation pathways of selected aromatic compounds. Catabolic pathways of naphthalene, fluorene, phenanthrene, fluoranthene, pyrene, and benzo[a]pyrene are described in detail. Bacterial catabolism of the heterocycles dibenzofuran, carbazole, dibenzothiophene, and dibenzodioxin is discussed. Bacterial catabolism of alkylated PAHs is summarized, followed by a brief discussion of proteomics and metabolomics as powerful tools for elucidation of biodegradation mechanisms.

  2. Cellulose degradation by oxidative enzymes

    Directory of Open Access Journals (Sweden)

    Maria Dimarogona

    2012-09-01

    Full Text Available Enzymatic degradation of plant biomass has attracted intensive research interest for the production of economically viable biofuels. Here we present an overview of the recent findings on biocatalysts implicated in the oxidative cleavage of cellulose, including polysaccharide monooxygenases (PMOs or LPMOs which stands for lytic PMOs, cellobiose dehydrogenases (CDHs and members of carbohydrate-binding module family 33 (CBM33. PMOs, a novel class of enzymes previously termed GH61s, boost the efficiency of common cellulases resulting in increased hydrolysis yields while lowering the protein loading needed. They act on the crystalline part of cellulose by generating oxidized and non-oxidized chain ends. An external electron donor is required for boosting the activity of PMOs. We discuss recent findings concerning their mechanism of action and identify issues and questions to be addressed in the future.

  3. CLAD DEGRADATION - FEPS SCREENING ARGUMENTS

    Energy Technology Data Exchange (ETDEWEB)

    R. Schreiner

    2004-10-21

    The purpose of this report is to evaluate and document the screening of the clad degradation features, events, and processes (FEPs) with respect to modeling used to support the Total System Performance Assessment-License Application (TSPA-LA). This report also addresses the effect of certain FEPs on both the cladding and the commercial spent nuclear fuel (CSNF), DOE-owned spent nuclear fuel (DSNF), and defense high-level waste (DHLW) waste forms, as appropriate to address the effects on multiple materials and both components (FEPs 2.1.09.09.0A, 2.1.09.11.0A, 2.1.11.05.0A, 2.1.12.02.0A, and 2.1.12.03.0A). These FEPs are expected to affect the repository performance during the postclosure regulatory period of 10,000 years after permanent closure. Table 1-1 provides the list of cladding FEPs, including their screening decisions (include or exclude). The primary purpose of this report is to identify and document the analysis, screening decision, and TSPA-LA disposition (for included FEPs) or screening argument (for excluded FEPs) for these FEPs related to clad degradation. In some cases, where a FEP covers multiple technical areas and is shared with other FEP reports, this report may provide only a partial technical basis for the screening of the FEP. The full technical basis for shared FEPs is addressed collectively by the sharing FEP reports. The screening decisions and associated TSPA-LA dispositions or screening arguments from all of the FEP reports are cataloged in a project-specific FEPs database.

  4. CLAD DEGRADATION - FEPS SCREENING ARGUMENTS

    International Nuclear Information System (INIS)

    The purpose of this report is to evaluate and document the screening of the clad degradation features, events, and processes (FEPs) with respect to modeling used to support the Total System Performance Assessment-License Application (TSPA-LA). This report also addresses the effect of certain FEPs on both the cladding and the commercial spent nuclear fuel (CSNF), DOE-owned spent nuclear fuel (DSNF), and defense high-level waste (DHLW) waste forms, as appropriate to address the effects on multiple materials and both components (FEPs 2.1.09.09.0A, 2.1.09.11.0A, 2.1.11.05.0A, 2.1.12.02.0A, and 2.1.12.03.0A). These FEPs are expected to affect the repository performance during the postclosure regulatory period of 10,000 years after permanent closure. Table 1-1 provides the list of cladding FEPs, including their screening decisions (include or exclude). The primary purpose of this report is to identify and document the analysis, screening decision, and TSPA-LA disposition (for included FEPs) or screening argument (for excluded FEPs) for these FEPs related to clad degradation. In some cases, where a FEP covers multiple technical areas and is shared with other FEP reports, this report may provide only a partial technical basis for the screening of the FEP. The full technical basis for shared FEPs is addressed collectively by the sharing FEP reports. The screening decisions and associated TSPA-LA dispositions or screening arguments from all of the FEP reports are cataloged in a project-specific FEPs database

  5. Bacterial degradation of glycol ethers.

    Science.gov (United States)

    Kawai, F

    1995-12-01

    Assimilation of ethyleneglycol (EG) ethers by polyethyleneglycol-utilizing bacteria was examined. Ethyleneglycol ether-utilizing bacteria were also isolated from soil and activated sludge samples by enrichment-culture techniques. Three strains (4-5-3, EC 1-2-1 and MC 2-2-1) were selected and characterized as Pseudomonas sp. 4-5-3, Xanthobacter autotrophicus, and an unidentified gram-negative, non-spore-forming rod respectively. Their growth characteristics were examined: Pseudomonas sp. 4-5-3 assimilated EG (diethyleneglycol, DEG) monomethyl, monoethyl and monobutyl ethers, DEG, propanol and butanol. X. autotrophicus EC 1-2-1 grew well on EG monoethyl and monobutyl ethers, EG and primary alcohols (C1-C4), and slightly on EG monomethyl ether. The strain MC 2-2-1 grew on EG monomethyl ether, EG, primary alcohols (C1-C4), and 1,2-propyleneglycol (PG). The mixed culture of Pseudomonas sp. 4-5-3 and X. autotrophicus EC 1-2-1 showed better growth and improved degradation than respective single cultures towards EG monomethyl, monoethyl or monobutyl ethers. Intact cells of Pseudomonas sp. 4-5-3 degraded various kinds of monoalkyl ethers, which cannot be assimilated by the strain. Metabolic products were characterized from reaction supernatants of intact cells of Pseudomonas sp. 4-5-3 with EG or DEG monoethyl ethers: they were analyzed by thin-layer chromatography and GC-MS and found to be ethoxyacetic acid and ethoxyglycoxyacetic acid. Also, PG monoalkyl ethers (C1-C4), dipropyleneglycol monoethyl and monomethyl ethers and tripropyleneglycol monomethyl ether were assimilated by polypropyleneglycol-utilizing Corynebacterium sp. 7. PMID:8597556

  6. Abiotic degradation of antibiotic ionophores

    International Nuclear Information System (INIS)

    Hydrolytic and photolytic degradation were investigated for the ionophore antibiotics lasalocid, monensin, salinomycin, and narasin. The hydrolysis study was carried out by dissolving the ionophores in solutions of pH 4, 7, and 9, followed by incubation at three temperatures of 6, 22, and 28 °C for maximum 34 days. Using LC–MS/MS for chemical analysis, lasalocid was not found to hydrolyse in any of the tested environments. Monensin, salinomycin, and narasin were all stable in neutral or alkaline solution but hydrolysed in the solution with a pH of 4. Half-lives at 25 °C were calculated to be 13, 0.6, and 0.7 days for monensin, salinomycin, and narasin, respectively. Absorbance spectra from each compound indicated that only lasalocid is degraded by photolysis (half-life below 1 h) due to an absorbance maximum around 303 nm, and monensin, salinomycin, and narasin are resistant to direct photolysis because they absorb light of environmentally irrelevant wavelengths. -- Highlights: •Constants for calculation of hydrolysis rates are estimated. •At 25 °C and a pH of 4, monensin hydrolyses with a half-life (t1/2) of 13 days. •Salinomycin and narasin hydrolyse with t1/2 of half a day at 25 °C and a pH of 4. •Lasalocid does not hydrolyse, but is likely to be susceptible to direct photolysis. •Monensin, salinomycin and narasin are not susceptible to direct photolysis. -- Antibiotic ionophores were found to undergo either hydrolysis in acidic environments (monensin, salinomycin, and narasin) or photolysis (lasalocid)

  7. Thermal degradation of organo-soluble polyimides

    Institute of Scientific and Technical Information of China (English)

    黄俐研; 史燚; 金熹高

    1999-01-01

    The thermal degradation behavior of two organo-soluble polyimides was investigated by high resolution pyrolysis-gas chromatography/mass spectrometry. The pyrolyzates of the polymers at various temperatures were identified and characterized quantitatively. The relationship between the polymer structure and pyrolyzate distribution was discussed. The kinetic parameters of the thermal degradation were calculated based on thermogravimetric measurements. Finally, the thermal degradation mechanism for the polymers was suggested.

  8. Degradation of Lignin by Cyathus Species

    OpenAIRE

    Abbott, Thomas P.; Wicklow, Donald T.

    1984-01-01

    The ability of 12 Cyathus species to degrade 14C-labeled lignin in kenaf was studied. The sum of 14C released into solution plus 14C released into the gas phase over a 32-day fermentation period was used to determine average daily rates of lignin biodegradation. Cyathus pallidus. C. africanus, and C. berkeleyanus delignified kenaf most rapidly. C. canna showed the greatest preference for lignin degradation over other plant components, and its rate of lignin degradation was only slightly lower...

  9. Mechanical strain and degradation of laser heterostructures

    Science.gov (United States)

    Ptashchenko, Alexander A.; Ptashchenko, Fedor A.; Maslejeva, Natalia V.; Sadova, Galina V.

    2001-02-01

    The effect of mechanical strain on degradation processes in GaAs-AlGaAs laser heterostructures (LHS) with stripe geometry and in light emitting diodes (LED) was experimentally studied. The strain was produced either by axial pressure or by indentation with a Wickers pyramid. We show that degradation affects the degree of polarization and the far-field distribution of laser emission. The effect of strain on the degradation intensity is estimated.

  10. Land Degradation Assessment and Monitoring of Drylands

    OpenAIRE

    Stellmes, M; Sonnenschein, Ruth; Roeder, A; Udelhoven, Thomas; Sommer, Stefan; HILL Joachim

    2015-01-01

    This chapter provides an overview of important studies on remote sensing of land degradation in drylands. Section17.2 presents general considerations regarding the assessment and monitoring of land degradation including suitable indicators as well as sensor systems. The following sections give a review of the state of the art on the assessmentof land condition (Section 17.3), the monitoring of LUCCs to assess land degradation processes (Section 17.4), and the identification of human-induce...

  11. Climate global change and land degradation

    International Nuclear Information System (INIS)

    Land degradation processes are firstly introduced within the framework of eco-pedological landscape systems; historical context is also considered. The main part of the paper deals with monitoring and predicting land degradation: the current state of land degradation is examined and the relationship of climate to various selected climate sensitive key processes (compaction, soil faunal depletion, etc.) is studied. Monitoring and prediction are illustrated with two examples from South Europe

  12. Degradation of connexins and gap junctions

    OpenAIRE

    Falk, Matthias M.; Kells, Rachael M.; Berthoud, Viviana M.

    2014-01-01

    Connexin proteins are short-lived within the cell, whether present in the secretory pathway or in gap junction plaques. Their levels can be modulated by their rate of degradation. Connexins, at different stages of assembly, are degraded through the proteasomal, endo-/lysosomal, and phago-/lysosomal pathways. In this review, we summarize the current knowledge about connexin and gap junction degradation including the signals and protein-protein interactions that participate in their targeting f...

  13. Soil degradation and prevention in greenhouse production

    OpenAIRE

    Liang, Y; Lin, X; Yamada, S; M. Inoue; Inosako, K

    2013-01-01

    Soil degradation has been a very serious problem for sustainable production, especially by a re-cropping of greenhouse-cultivated cucumber (Cucumis statirus L.). The aim of this research was to expound the actuality for soil degradation, at the same time, put forward some suggestion for preventing from soil degradation and maintain sustainable production in greenhouse basic on the two experiments conducted in a solar greenhouse during 2001-2008 suburb area of Yan'an, Shaanxi province in North...

  14. Prevention methods against hydrogen degradation of steel

    OpenAIRE

    J. Ćwiek

    2010-01-01

    Purpose: of this paper is presentation of mechanisms and forms of hydrogen degradation in steel along with pointing out methods for hydrogen degradation prevention.Design/methodology/approach: Hydrogen degradation of steel is a form of environmentally assisted failure which is caused by the action of hydrogen often in combination with residual or applied stress resulting in reduction of plasticity, load bearing capacity of a component, and cracking.Findings: The sources of hydrogen in steel w...

  15. Directional Degradation of Lignocellulose by Phlebia radiata

    OpenAIRE

    Hatakka, Annele I.; Rogalski, Jerzy; Ohga, Shoji

    2009-01-01

    The white-rot fungus Phlebia radiata preferably degrades lignin and is thus a potential fungus for biopulping and other applications in the pulp and paper industry. To elucidate important factors involved in the degradation of lignin carbohydrate complex (LCC) by this fungus, the metabolism of [U-^14C]-labelled wheat straw, [^14C]-labelled cellulose and [^14C]-labelled wheat straw hemicellulose was studied. The degradation of hemicellulose and lignin were apparently linked together and contro...

  16. Autonomous valve for detection of biopolymer degradation

    OpenAIRE

    Keller, Stephan Urs; Noeth, Nadine-Nicole; Fetz, Stefanie; Grünefeld, Marco; Geschke, Oliver; Boisen, Anja; Haefliger, D.

    2009-01-01

    We present a polymer microvalve that allows the detection of biopolymer degradation without the need of external energy. The valve is based on a polymer container filled with a colored marker solution and closed by a thin lid. This structure is covered by a film of poly(L-lactide) and degradation of the biopolymer triggers the release of the color which is detected visually. The autonomous valve has potential for the fast testing of biopolymer degradation under various environmental condition...

  17. Durability Improvements Through Degradation Mechanism Studies

    Energy Technology Data Exchange (ETDEWEB)

    Borup, Rodney L. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Mukundan, Rangachary [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Spernjak, Dusan [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Baker, Andrew M. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Lujan, Roger W. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Langlois, David Alan [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Ahluwalia, Rajesh [Argonne National Lab. (ANL), Argonne, IL (United States); Papadia, D. D. [Argonne National Lab. (ANL), Argonne, IL (United States); Weber, Adam Z. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Kusoglu, Ahmet [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); Shi, Shouwnen [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States); More, K. L. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Grot, Steve [Ion Power, New Castle, DE (United States)

    2015-08-03

    The durability of polymer electrolyte membrane (PEM) fuel cells is a major barrier to the commercialization of these systems for stationary and transportation power applications. By investigating cell component degradation modes and defining the fundamental degradation mechanisms of components and component interactions, new materials can be designed to improve durability. To achieve a deeper understanding of PEM fuel cell durability and component degradation mechanisms, we utilize a multi-institutional and multi-disciplinary team with significant experience investigating these phenomena.

  18. Degradation of Ochratoxin A by Brevibacterium Species

    OpenAIRE

    Rodriguez, Héctor; Reverón, Inés; Doria, Francesca; Costantini, Antonella; Rivas, Blanca de las; Muñoz, Rosario; García-Moruno, Emilia

    2011-01-01

    The ability to degrade ochratoxin A was studied in different bacteria with a well-known capacity to transform aromatic compounds. Strains belonging to Rhodococcus, Pseudomonas, and Brevibacterium genera were grown in liquid synthetic culture medium containing ochratoxin A. Brevibacterium spp. strains showed 100% degradation of ochratoxin A.Ochratoxin ¿ was detected and identified by high-performance liquid chromatographymass spectrometry (HPLC-MS) as a degradation product in the cellfree supe...

  19. Anomaly Detection and Degradation Prediction of MOSFET

    OpenAIRE

    Li-Feng Wu; Yong Guan; Xiao-Juan Li; Jie Ma

    2015-01-01

    The MOSFET is an important power electronic transistor widely used in electrical systems. Its reliability has an effect on the performance of systems. In this paper, the failure models and mechanisms of MOSFETs are briefly analyzed. The on-resistance Ron is the key failure precursor parameter representing the degree of degradation. Based on the experimental data, a nonlinear dual-exponential degradation model for MOSFETs is obtained. Then, we present an approach for MOSFET degradation state p...

  20. Mitofusin 1 is degraded at G2/M phase through ubiquitylation by MARCH5

    Directory of Open Access Journals (Sweden)

    Park Yong-Yea

    2012-12-01

    Full Text Available Abstract Background Mitochondria exhibit a dynamic morphology in cells and their biogenesis and function are integrated with the nuclear cell cycle. In mitotic cells, the filamentous network structure of mitochondria takes on a fragmented form. To date, however, whether mitochondrial fusion activity is regulated in mitosis has yet to be elucidated. Findings Here, we report that mitochondria were found to be fragmented in G2 phase prior to mitotic entry. Mitofusin 1 (Mfn1, a mitochondrial fusion protein, interacted with cyclin B1, and their interactions became stronger in G2/M phase. In addition, MARCH5, a mitochondrial E3 ubiquitin ligase, reduced Mfn1 levels and the MARCH5-mediated Mfn1 ubiquitylation were enhanced in G2/M phase. Conclusions Mfn1 is degraded through the MARCH5-mediated ubiquitylation in G2/M phase and the cell cycle-dependent degradation of Mfn1 could be facilitated by interaction with cyclin B1/Cdk1 complexes.

  1. Assessing the Private Costs of Soil Degradation

    OpenAIRE

    Home, P

    1992-01-01

    While there is widespread concern in the Australian community with the extent of soil degradation, there is a paucity of reliable information on the extent of the costs that this degradation is imposing on Australia. A simple conceptual model of the private costs of soil degradation is outlined. On the basis of this model conventional measures of private soil degradation costs, such as the value of lost soil or production, the cost of repair and the opportunity cost of soil, are shown to have...

  2. Thermal degradation of TBP-diluent systems

    International Nuclear Information System (INIS)

    The influence of the temperature, the concentration of nitric acid, the diluent, as well as the influence of uranyl, zirconyl and palladium nitrates on the thermal degradation of TBP-HNO3 system have been studied. On the basis of the yield of HDBP, organic nitrites, nitro- and ca'onyl compounds, and retention of uranium in degraded solvent have been shown that, diluent and uranyl nitrate have a great influence on thermal degradation TBP-HNOL3 system. The effect of zirconyl and palladium nitrate n the thermal degradation is insignificant. (author)

  3. Degradation of ascorbic acid in ethanolic solutions.

    Science.gov (United States)

    Hsu, Hsin-Yun; Tsai, Yi-Chin; Fu, Chi-Chang; Wu, James Swi-Bea

    2012-10-24

    Ascorbic acid occurs naturally in many wine-making fruits. The industry also uses ascorbic acid as an antioxidant and color stabilizer in the making of alcoholic beverages including white wine, wine cooler, alcopop, and fruit liqueur. However, the degradation of ascorbic acid itself may cause browning and the deterioration of color quality. This study was aimed to monitor the degradation of ascorbic acid, the formation of degradation products, and the browning in storage of ascorbic acid containing 0-40% (v/v) ethanolic solutions buffered at pH 3.2 as models of alcoholic beverages. The results show that ascorbic acid degradation in the ethanolic solutions during storage follows first-order reaction, that the degradation and browning rates increase with the increase of ethanol concentration, that the activation energy for the degradation of ascorbic acid is in the range 10.35-23.10 (kcal/mol), that 3-hydroxy-2-pyrone is an indicator and a major product of ascorbic acid degradation, and that aerobic degradation pathway dominants over anaerobic pathway in ascorbic acid degradation in ethanolic solutions. PMID:22994409

  4. Photovoltaic Degradation Rates -- An Analytical Review

    Energy Technology Data Exchange (ETDEWEB)

    Jordan, D. C.; Kurtz, S. R.

    2012-06-01

    As photovoltaic penetration of the power grid increases, accurate predictions of return on investment require accurate prediction of decreased power output over time. Degradation rates must be known in order to predict power delivery. This article reviews degradation rates of flat-plate terrestrial modules and systems reported in published literature from field testing throughout the last 40 years. Nearly 2000 degradation rates, measured on individual modules or entire systems, have been assembled from the literature, showing a median value of 0.5%/year. The review consists of three parts: a brief historical outline, an analytical summary of degradation rates, and a detailed bibliography partitioned by technology.

  5. Simulating Degradation Data for Prognostic Algorithm Development

    Data.gov (United States)

    National Aeronautics and Space Administration — PHM08 Challenge Dataset is now publicly available at the NASA Prognostics Respository + Download INTRODUCTION - WHY SIMULATE DEGRADATION DATA? Of various challenges...

  6. Current State of Knowledge in Microbial Degradation of Polycyclic Aromatic Hydrocarbons (PAHs): A Review

    Science.gov (United States)

    Ghosal, Debajyoti; Ghosh, Shreya; Dutta, Tapan K.; Ahn, Youngho

    2016-01-01

    Polycyclic aromatic hydrocarbons (PAHs) include a group of organic priority pollutants of critical environmental and public health concern due to their toxic, genotoxic, mutagenic and/or carcinogenic properties and their ubiquitous occurrence as well as recalcitrance. The increased awareness of their various adverse effects on ecosystem and human health has led to a dramatic increase in research aimed toward removing PAHs from the environment. PAHs may undergo adsorption, volatilization, photolysis, and chemical oxidation, although transformation by microorganisms is the major neutralization process of PAH-contaminated sites in an ecologically accepted manner. Microbial degradation of PAHs depends on various environmental conditions, such as nutrients, number and kind of the microorganisms, nature as well as chemical property of the PAH being degraded. A wide variety of bacterial, fungal and algal species have the potential to degrade/transform PAHs, among which bacteria and fungi mediated degradation has been studied most extensively. In last few decades microbial community analysis, biochemical pathway for PAHs degradation, gene organization, enzyme system, genetic regulation for PAH degradation have been explored in great detail. Although, xenobiotic-degrading microorganisms have incredible potential to restore contaminated environments inexpensively yet effectively, but new advancements are required to make such microbes effective and more powerful in removing those compounds, which were once thought to be recalcitrant. Recent analytical chemistry and genetic engineering tools might help to improve the efficiency of degradation of PAHs by microorganisms, and minimize uncertainties of successful bioremediation. However, appropriate implementation of the potential of naturally occurring microorganisms for field bioremediation could be considerably enhanced by optimizing certain factors such as bioavailability, adsorption and mass transfer of PAHs. The main

  7. The Endosome-associated Deubiquitinating Enzyme USP8 Regulates BACE1 Enzyme Ubiquitination and Degradation.

    Science.gov (United States)

    Yeates, Eniola Funmilayo Aduke; Tesco, Giuseppina

    2016-07-22

    The β-site amyloid precursor protein-cleaving enzyme (BACE1) is the rate-limiting enzyme in the production of amyloid-β, the toxic peptide that accumulates in the brain of subjects affected by Alzheimer disease. Our previous studies have shown that BACE1 is degraded via the lysosomal pathway and that that depletion of the trafficking molecule Golgi-localized γ-ear-containing ARF-binding protein 3 (GGA3) results in increased BACE1 levels and activity because of impaired lysosomal degradation. We also determined that GGA3 regulation of BACE1 levels requires its ability to bind ubiquitin. Accordingly, we reported that BACE1 is ubiquitinated at lysine 501 and that lack of ubiquitination at lysine 501 produces BACE1 stabilization. Ubiquitin conjugation is a reversible process mediated by deubiquitinating enzymes. The ubiquitin-specific peptidase 8 (USP8), an endosome-associated deubiquitinating enzyme, regulates the ubiquitination, trafficking, and lysosomal degradation of several plasma membrane proteins. Here, we report that RNAi-mediated depletion of USP8 reduced levels of both ectopically expressed and endogenous BACE1 in H4 human neuroglioma cells. Moreover, USP8 depletion increased BACE1 ubiquitination, promoted BACE1 accumulation in the early endosomes and late endosomes/lysosomes, and decreased levels of BACE1 in the recycling endosomes. We also found that decreased BACE1 protein levels were accompanied by a decrease in BACE1-mediated amyloid precursor protein cleavage and amyloid-β levels. Our findings demonstrate that USP8 plays a key role in the trafficking and degradation of BACE1 by deubiquitinating lysine 501. These studies suggest that therapies able to accelerate BACE1 degradation (e.g. by increasing BACE1 ubiquitination) may represent a potential treatment for Alzheimer disease. PMID:27302062

  8. Fenofibrate activates Nrf2 through p62-dependent Keap1 degradation

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jeong Su [Severance Biomedical Science Institute (Korea, Republic of); Yonsei Biomedical Research Institute, Yonsei University College of Medicine, 50 Yonsei-ro, Seodaemun-gu, Seoul 120-752 (Korea, Republic of); Kang, Dong Hoon [Department of Life Science and Ewha Research Center for Systems Biology (Korea, Republic of); The Research Center for Cell Homeostasis, Ewha Womans University, Seoul 127-750 (Korea, Republic of); Lee, Da Hyun [Severance Biomedical Science Institute (Korea, Republic of); Yonsei Biomedical Research Institute, Yonsei University College of Medicine, 50 Yonsei-ro, Seodaemun-gu, Seoul 120-752 (Korea, Republic of); Bae, Soo Han, E-mail: soohanbae@yuhs.ac [Severance Biomedical Science Institute (Korea, Republic of); Yonsei Biomedical Research Institute, Yonsei University College of Medicine, 50 Yonsei-ro, Seodaemun-gu, Seoul 120-752 (Korea, Republic of)

    2015-09-25

    Peroxisome proliferator-activated receptor α (PPARα) activates the β-oxidation of fatty acids in the liver. Fenofibrate is a potent agonist of PPARα and is used in the treatment of hyperlipidemia. Fenofibrate treatment often induces the production of intracellular reactive oxygen species (ROS), leading to cell death. The nuclear factor erythroid 2-related factor 2 (Nrf2)-Kelch-like ECH-associated protein 1 (Keap1) pathway is an essential component of the defense mechanism against oxidative stress. However, the molecular mechanism underlying the regulation of the Nrf2-Keap1 pathway in fenofibrate-induced cell death is not known. In this study, we demonstrated that fenofibrate induces Keap1 degradation and Nrf2 activation. This fenofibrate-mediated Keap1 degradation is partly dependent on autophagy. Furthermore, fenofibrate-induced Keap1 degradation followed by Nrf2 activation is mainly mediated by p62, which functions as an adaptor protein in the autophagic pathway. Consistent with these findings, ablation of p62 increased fenofibrate-mediated apoptotic cell death associated with ROS accumulation. These results strongly suggest that p62 plays a crucial role in preventing fenofibrate-induced cell death. - Highlights: • Fenofibrate induces cell death by increasing ROS production. • The underlying defense mechanism against this effect is unknown. • Fenofibrate induces autophagy-dependent Keap1 degradation and Nrf2 activation. • This process is p62-dependent; lack of p62 enhanced fenofibrate-mediated apoptosis. • p62 plays a crucial role in preventing fenofibrate-induced cell death.

  9. Lamins, laminopathies and disease mechanisms: Possible role for proteasomal degradation of key regulatory proteins

    Indian Academy of Sciences (India)

    Veena K Parnaik; Pankaj Chaturvedi; B H Muralikrishna

    2011-08-01

    Lamins are major structural proteins of the nucleus and are essential for nuclear integrity and organization of nuclear functions. Mutations in the human lamin genes lead to highly degenerative genetic diseases that affect a number of different tissues such as muscle, adipose or neuronal tissues, or cause premature ageing syndromes. New findings on the role of lamins in cellular signalling pathways, as well as in ubiquitin-mediated proteasomal degradation, have given important insights into possible mechanisms of pathogenesis.

  10. Fenofibrate activates Nrf2 through p62-dependent Keap1 degradation

    International Nuclear Information System (INIS)

    Peroxisome proliferator-activated receptor α (PPARα) activates the β-oxidation of fatty acids in the liver. Fenofibrate is a potent agonist of PPARα and is used in the treatment of hyperlipidemia. Fenofibrate treatment often induces the production of intracellular reactive oxygen species (ROS), leading to cell death. The nuclear factor erythroid 2-related factor 2 (Nrf2)-Kelch-like ECH-associated protein 1 (Keap1) pathway is an essential component of the defense mechanism against oxidative stress. However, the molecular mechanism underlying the regulation of the Nrf2-Keap1 pathway in fenofibrate-induced cell death is not known. In this study, we demonstrated that fenofibrate induces Keap1 degradation and Nrf2 activation. This fenofibrate-mediated Keap1 degradation is partly dependent on autophagy. Furthermore, fenofibrate-induced Keap1 degradation followed by Nrf2 activation is mainly mediated by p62, which functions as an adaptor protein in the autophagic pathway. Consistent with these findings, ablation of p62 increased fenofibrate-mediated apoptotic cell death associated with ROS accumulation. These results strongly suggest that p62 plays a crucial role in preventing fenofibrate-induced cell death. - Highlights: • Fenofibrate induces cell death by increasing ROS production. • The underlying defense mechanism against this effect is unknown. • Fenofibrate induces autophagy-dependent Keap1 degradation and Nrf2 activation. • This process is p62-dependent; lack of p62 enhanced fenofibrate-mediated apoptosis. • p62 plays a crucial role in preventing fenofibrate-induced cell death

  11. Chymotrypsin C (caldecrin) promotes degradation of human cationic trypsin: Identity with Rinderknecht's enzyme Y

    OpenAIRE

    Szmola, Richárd; Sahin-Tóth, Miklós

    2007-01-01

    Digestive trypsins undergo proteolytic breakdown during their transit in the human alimentary tract, which has been assumed to occur through trypsin-mediated cleavages, termed autolysis. Autolysis was also postulated to play a protective role against pancreatitis by eliminating prematurely activated intrapancreatic trypsin. However, autolysis of human cationic trypsin is very slow in vitro, which is inconsistent with the documented intestinal trypsin degradation or a putative protective role....

  12. Deposition and degradation of C3 on type III group B streptococci.

    OpenAIRE

    Campbell, J R; Baker, C J; Edwards, M S

    1991-01-01

    Antibody to the polysaccharide capsule of type III group B streptococci (GBS) and complement are essential to host defense against systemic infection in neonates. Interactions between C3 degradation products and specific neutrophil receptors mediate the attachment and ingestion of these organisms. To evaluate the influence of capsule on C3 disposition, we compared the C3 fragments released from a highly encapsulated clinical isolate (M861) with those from an unencapsulated mutant (COH 31-15) ...

  13. GP96 Interacts with HHV-6 during Viral Entry and Directs It for Cellular Degradation

    OpenAIRE

    Prusty, Bhupesh K.; Christine Siegl; Nitish Gulve; Yasuko Mori; Thomas Rudel

    2015-01-01

    CD46 and CD134 mediate attachment of Human Herpesvirus 6A (HHV-6A) and HHV-6B to host cell, respectively. But many cell types interfere with viral infection through rapid degradation of viral DNA. Hence, not all cells expressing these receptors are permissive to HHV-6 DNA replication and production of infective virions suggesting the involvement of additional factors that influence HHV-6 propagation. Here, we used a proteomics approach to identify other host cell proteins necessary for HHV-6 ...

  14. Mechanisms of humic substances degradation by fungi

    Science.gov (United States)

    Chen, Y.; Hadar, Y.; Grinhut, T.

    2012-04-01

    Humic substances (HS) are formed by secondary synthesis reactions (humification) during the decay process and transformation of biomolecules originating from plants and other dead organisms. In nature, HS are extremely resistant to biological degradation. Thus, these substances are major components in the C cycle and in the biosphere and therefore, the understanding of the process leading to their formation and transformation and degradation is vital. Fungi active in the decomposition process of HS include mainly ascomycetes and basidiomycetes that are common in the upper layer of forest and grassland soils. Many basidiomycetes belong to the white-rot fungi (WRF) and litter-decomposing fungi (LDF). These fungi are considered to be the most efficient lignin degraders due to their nonspecific oxidizing enzymes: manganese peroxidase (MnP), lignin peroxidase (LiP) and laccase. Although bacteria dominate compost and participate in the turnover of HS, their ability to degrade stable macromolecules such as lignin and HS is limited. The overall objectives of this research were to corroborate biodegradation processes of HS by WRF. The specific objectives were: (i) To isolate, identify and characterize HS degrading WRF from biosolids (BS) compost; (ii) To study the biodegradation process of three types of HS, which differ in their structure, by WRF isolated from BS compost; and (iii) To investigate the mechanisms of HA degradation by WRF using two main approaches: (a) Study the physical and chemical analyses of the organic compounds obtained from direct fungal degradation of HA as well as elucidation of the relevant enzymatic reactions; and (b) Study the enzymatic and biochemical mechanisms involved during HA degradation. In order to study the capability of fungi to degrade HS, seventy fungal strains were isolated from biosolids (BS) compost. Two of the most active fungal species were identified based on rDNA sequences and designated Trametes sp. M23 and Phanerochaetesp., Y6

  15. Rotenone Upregulates Alpha-Synuclein and Myocyte Enhancer Factor 2D Independently from Lysosomal Degradation Inhibition

    Directory of Open Access Journals (Sweden)

    Gessica Sala

    2013-01-01

    Full Text Available Dysfunctions of chaperone-mediated autophagy (CMA, the main catabolic pathway for alpha-synuclein, have been linked to the pathogenesis of Parkinson’s disease (PD. Since till now there is limited information on how PD-related toxins may affect CMA, in this study we explored the effect of mitochondrial complex I inhibitor rotenone on CMA substrates, alpha-synuclein and MEF2D, and effectors, lamp2A and hsc70, in a human dopaminergic neuroblastoma SH-SY5Y cell line. Rotenone induced an upregulation of alpha-synuclein and MEF2D protein levels through the stimulation of their de novo synthesis rather than through a reduction of their CMA-mediated degradation. Moreover, increased MEF2D transcription resulted in higher nuclear protein levels that exert a protective role against mitochondrial dysfunction and oxidative stress. These results were compared with those obtained after lysosome inhibition with ammonium chloride. As expected, this toxin induced the cytosolic accumulation of both alpha-synuclein and MEF2D proteins, as the result of the inhibition of their lysosome-mediated degradation, while, differently from rotenone, ammonium chloride decreased MEF2D nuclear levels through the downregulation of its transcription, thus reducing its protective function. These results highlight that rotenone affects alpha-synuclein and MEF2D protein levels through a mechanism independent from lysosomal degradation inhibition.

  16. Glycosylated Benzoxazinoids Are Degraded during Fermentation of Wheat Bran.

    Science.gov (United States)

    Savolainen, Otto; Pekkinen, Jenna; Katina, Kati; Poutanen, Kaisa; Hanhineva, Kati

    2015-07-01

    Benzoxazinoids are plant secondary metabolites found in whole grain cereal foods including bread. They are bioavailable and metabolized in humans, and therefore their potential bioactivity is of interest. However, effects of food processing on their content and structure are not yet studied. This study reports effects of bioprocessing on wheat bran benzoxazinoid content. Benzoxazinoid glycosides were completely degraded during fermentation, whereas metabolites of benzoxazinoid aglycones were formed. Fermentation conditions did not affect the conversion process, as both yeast and yeast/lactic acid bacteria mediated fermentations had generally similar impacts. Likewise, enzymatic treatment of the bioprocess samples did not affect the conversion, suggesting that these compounds most likely are freely bioavailable from the grain matrix and not linked to the cell wall polymers. Additionally, the results show that benzoxazinoids undergo structural conversion during the fermentation process, resulting in several unknown compounds that contribute to the phytochemical intake and necessitate further analysis. PMID:26040909

  17. The VTLISFG motif in the BH1 domain plays a significant role in regulating the degradation of Mcl-1

    Directory of Open Access Journals (Sweden)

    Kang Xiao

    2014-01-01

    Full Text Available Mcl-1 is a member of the Bcl-2 family protein; its degradation is required for the initiation of apoptosis. The mechanism, however, is not yet clearly known. Previously, it was reported that Mcl-1 is degraded through the ubiquitination-mediated pathway and the PEST domain is the motif responsible for promoting this degradation. We found evidence that this may not be true. We generated several Mcl-1 deletion mutants and examined their effects on protein stability. Deletion of the PEST domain did not prevent the degradation of Mcl-1 during apoptosis. The BH1 domain, but not the PEST, BH3 or BH2 domain, exhibited a short half-life. A peptide named “F3” (VTLISFG in the C-terminus of the BH1 domain appears to be critical for the rapid turnover of Mcl-1. Deletion of F3 from GFP-Mcl-1-ΔPEST retarded the degradation of this mutant. F3 appeared to be the minimum functional sequence of the degradation motif, since deletion of a single residue was sufficient to abrogate its short half-life. Fusion of F3 with p32 resulted in the degradation of p32 during UV-induced apoptosis, while wild type p32 was not affected. Taken together, these findings suggest that F3 (VTLISFG, instead of PEST, is the major motif responsible for the degradation of Mcl-1 during apoptosis.

  18. Smad3 recruits the anaphase-promoting complex for ubiquitination and degradation of SnoN

    Energy Technology Data Exchange (ETDEWEB)

    Stroschein, Shannon L.; Bonni, Shirin; Wrana, Jeffrey L.; Luo, Kunxin

    2001-09-11

    Smad proteins mediate transforming growth factor-b signaling to regulate cell growth and differentiation. SnoN is an important negative regulator of TGFb signaling that functions to maintain the repressed state of TGFb target genes in the absence of ligand. Upon TGFb stimulation, Smad3 and Smad2 translocate into the nucleus and induce a rapid degradation of SnoN, allowing activation of TGFb target genes. Here we show that Smad2- or Smad3-induced degradation of SnoN requires the ubiquitin-dependent proteasome and can be mediated by the anaphase promoting complex (APC) and the UbcH5 family of ubiquitin conjugating enzymes. Smad3 and to a lesser extent, Smad2, interact with both the APC and SnoN, resulting in the recruitment of the APC to SnoN and subsequent ubiquitination of SnoN in a destruction box-dependent manner. In addition to the destruction box, efficient degradation of SnoN also requires the Smad3 binding site in SnoN as well as key lysine residues necessary for ubiquitin attachment. Mutation of either the Smad3 binding site or lysine residues results in stabilization of SnoN and in enhanced antagonism of TGFb signaling. Our studies elucidate an important pathway for the degradation of SnoN and reveal a novel role of the APC in regulation of TGFb signaling.

  19. Strain-Dependent Effect of Macroautophagy on Abnormally Folded Prion Protein Degradation in Infected Neuronal Cells.

    Directory of Open Access Journals (Sweden)

    Daisuke Ishibashi

    Full Text Available Prion diseases are neurodegenerative disorders caused by the accumulation of abnormal prion protein (PrPSc in the central nervous system. With the aim of elucidating the mechanism underlying the accumulation and degradation of PrPSc, we investigated the role of autophagy in its degradation, using cultured cells stably infected with distinct prion strains. The effects of pharmacological compounds that inhibit or stimulate the cellular signal transduction pathways that mediate autophagy during PrPSc degradation were evaluated. The accumulation of PrPSc in cells persistently infected with the prion strain Fukuoka-1 (FK, derived from a patient with Gerstmann-Sträussler-Scheinker syndrome, was significantly increased in cultures treated with the macroautophagy inhibitor 3-methyladenine (3MA but substantially reduced in those treated with the macroautophagy inducer rapamycin. The decrease in FK-derived PrPSc levels was mediated, at least in part, by the phosphatidylinositol 3-kinase/MEK signalling pathway. By contrast, neither rapamycin nor 3MA had any apparently effect on PrPSc from either the 22L or the Chandler strain, indicating that the degradation of PrPSc in host cells might be strain-dependent.

  20. Feedbacks between vegetation pattern and resource loss enhance degradation potential in drylands

    Science.gov (United States)

    Mayor, Ángeles G.; Kéfi, Sonia; Bautista, Susana; Rodríguez, Francisco; Cartení, Fabrizio; Rietkerk, Max

    2013-04-01

    Conceptual frameworks of dryland degradation commonly include ecohydrological feedbacks between landscape spatial organization and resource loss, so that decreasing cover and size of vegetation patches result in higher water and soil losses, which lead to further vegetation loss. However, the impacts of these feedbacks on dryland dynamics in response to external stress have barely been tested. Using a spatially-explicit model, we mimicked feedbacks between vegetation pattern and landscape resource loss by establishing a negative dependence of plant establishment on bare-soil hydrological connectivity. We assessed the impact of various feedback strengths on the response of dryland ecosystems to changing human and climatic pressure. The connectivity-mediated feedbacks decrease the amount of pressure required to cause a critical shift to a degraded state and increase the pressure release needed to achieve the ecosystem recovery. The impact of these feedbacks is markedly non-linear, which is explained by the non-linear increase in bare-soil hydrological connectivity with decreasing vegetation cover. Modelling studies on dryland vegetation dynamics not accounting for the connectivity-mediated feedbacks studied here may underestimate the degradation potential of drylands in response to external stress. Our results also suggest that changes in vegetation pattern and associated hydrological connectivity may be more informative early-warning indicators of dryland degradation than changes in vegetation cover.

  1. [Immune-mediated neuropathies].

    Science.gov (United States)

    Stoll, G; Reiners, K

    2016-08-01

    The Guillain-Barré syndrome (GBS) and chronic inflammatory demyelinating polyneuropathy (CIDP) are the most common immune-mediated polyneuropathies, which can show variable clinical and electrophysiological manifestations. Rarer immune-mediated neuropathies encompass paraproteinemic neuropathies (PPN), multifocal motor neuropathy (MMN) and vasculitic neuropathies. The diagnosis usually relies on the history of symptom evolution, distribution of nerve dysfunction and particularly on characteristic features in nerve conduction studies, aided by cerebrospinal fluid (CSF) examination and nerve biopsy findings. The therapeutic toolbox encompasses corticosteroids, immunoglobulins and plasmapheresis often accompanied by long-term immunosuppression. It is important to note that immune-mediated neuropathies selectively respond to treatment and contraindications need to be considered. Despite treatment a considerable number of patients suffer from permanent neurological deficits. PMID:27474733

  2. The Strategic Mediator

    DEFF Research Database (Denmark)

    Rossignoli, Cecilia; Carugati, Andrea; Mola, Lapo

    2009-01-01

    The last 10 years have witnessed the emergence of electronic marketplaces as players that leverage new technologies to facilitate B2B internet-mediated collaborative business. Nowadays these players are augmenting their services from simple intermediation to include new inter-organizational relat......The last 10 years have witnessed the emergence of electronic marketplaces as players that leverage new technologies to facilitate B2B internet-mediated collaborative business. Nowadays these players are augmenting their services from simple intermediation to include new inter...... e-marketplace assumes the paradoxical role of strategic mediator: an agent who upholds and heightens the fences of the transactions instead of leveling them. The results have implication in shaping how we see the role of technology as strategic or commoditized....

  3. Immunologically mediated oral diseases

    Directory of Open Access Journals (Sweden)

    Sudha Jimson

    2015-01-01

    Full Text Available Immune mediated diseases of oral cavity are uncommon. The lesions may be self-limiting and undergo remission spontaneously. Among the immune mediated oral lesions the most important are lichen planus, pemphigus, erythema multiformi, epidermolysis bullosa, systemic lupus erythematosis. Cellular and humoral mediated immunity play a major role directed against epithelial and connective tissue in chronic and recurrent patterns. Confirmatory diagnosis can be made by biopsy, direct and indirect immunoflouresence, immune precipitation and immunoblotting. Therapeutic agents should be selected after thorough evaluation of immune status through a variety of tests and after determining any aggravating or provoking factors. Early and appropriate diagnosis is important for proper treatment planning contributing to better prognosis and better quality of life of patient.

  4. Immunologically mediated oral diseases.

    Science.gov (United States)

    Jimson, Sudha; Balachader, N; Anita, N; Babu, R

    2015-04-01

    Immune mediated diseases of oral cavity are uncommon. The lesions may be self-limiting and undergo remission spontaneously. Among the immune mediated oral lesions the most important are lichen planus, pemphigus, erythema multiformi, epidermolysis bullosa, systemic lupus erythematosis. Cellular and humoral mediated immunity play a major role directed against epithelial and connective tissue in chronic and recurrent patterns. Confirmatory diagnosis can be made by biopsy, direct and indirect immunoflouresence, immune precipitation and immunoblotting. Therapeutic agents should be selected after thorough evaluation of immune status through a variety of tests and after determining any aggravating or provoking factors. Early and appropriate diagnosis is important for proper treatment planning contributing to better prognosis and better quality of life of patient. PMID:26015713

  5. Involvement of ADAMTS5 and hyaluronidase in aggrecan degradation and release from OSM-stimulated cartilage

    Directory of Open Access Journals (Sweden)

    M Durigova

    2011-01-01

    Full Text Available The relative contribution of a disintegrin and metalloproteinase with thrombospondin motifs (ADAMTS4 and ADAMTS5 to aggrecan degradation under oncostatin M (OSM stimulation, the role of the ancillary domains of the aggrecanases on their ability to cleave within the chondroitin sulfate (CS-2 region, the role of hyaluronidases (HYAL in stimulating aggrecan release in the absence of proteolysis, and the identity of the hyaluronidase involved in OSM-mediated cartilage breakdown were investigated. Bovine articular cartilage explants were cultured in the presence of interleukin-1beta (IL-1beta, tumor necrosis factor alpha (TNFalpha and/or OSM, or treated with trypsin and/or hyaluronidase. Aggrecan was digested with various domain-truncated isoforms of ADAMTS4 and ADAMTS5. Aggrecan and link protein degradation and release were analyzed by immunoblotting. Aggrecanase and HYAL gene expression were determined. ADAMTS4 was the most inducible aggrecanase upon cytokine stimulation, whereas ADAMTS5 was the most abundant aggrecanase. ADAMTS5 was the most active aggrecanase and was responsible for the generation of an OSM-specific degradation pattern in the CS-2 region. Its ability to cleave at the OSM-specific site adjacent to the aggrecan G3 region was enhanced by truncation of the C-terminal thrombospondin domain, but reduced by further truncation of both the spacer and cysteine-rich domains of the enzyme. OSM has the ability to mediate proteoglycan release through hyaluronan degradation, under conditions where HYAL-2 is the predominant hyaluronidase being expressed. Compared to other catabolic cytokines, OSM exhibits a unique potential at degrading the proteoglycan aggregate, by promoting early robust aggrecanolysis, primarily through the action of ADAMTS5, and hyaluronan degradation.

  6. ZEAXANTHIN EPOXIDASE Activity Potentiates Carotenoid Degradation in Maturing Seed.

    Science.gov (United States)

    Gonzalez-Jorge, Sabrina; Mehrshahi, Payam; Magallanes-Lundback, Maria; Lipka, Alexander E; Angelovici, Ruthie; Gore, Michael A; DellaPenna, Dean

    2016-07-01

    Elucidation of the carotenoid biosynthetic pathway has enabled altering the composition and content of carotenoids in various plants, but to achieve desired nutritional impacts, the genetic components regulating carotenoid homeostasis in seed, the plant organ consumed in greatest abundance, must be elucidated. We used a combination of linkage mapping, genome-wide association studies (GWAS), and pathway-level analysis to identify nine loci that impact the natural variation of seed carotenoids in Arabidopsis (Arabidopsis thaliana). ZEAXANTHIN EPOXIDASE (ZEP) was the major contributor to carotenoid composition, with mutants lacking ZEP activity showing a remarkable 6-fold increase in total seed carotenoids relative to the wild type. Natural variation in ZEP gene expression during seed development was identified as the underlying mechanism for fine-tuning carotenoid composition, stability, and ultimately content in Arabidopsis seed. We previously showed that two CAROTENOID CLEAVAGE DIOXYGENASE enzymes, CCD1 and CCD4, are the primary mediators of seed carotenoid degradation, and here we demonstrate that ZEP acts as an upstream control point of carotenoid homeostasis, with ZEP-mediated epoxidation targeting carotenoids for degradation by CCD enzymes. Finally, four of the nine loci/enzymatic activities identified as underlying natural variation in Arabidopsis seed carotenoids also were identified in a recent GWAS of maize (Zea mays) kernel carotenoid variation. This first comparison of the natural variation in seed carotenoids in monocots and dicots suggests a surprising overlap in the genetic architecture of these traits between the two lineages and provides a list of likely candidates to target for selecting seed carotenoid variation in other species. PMID:27208224

  7. Constitutive and ligand-induced TCR degradation

    DEFF Research Database (Denmark)

    von Essen, Marina; Bonefeld, Charlotte Menné; Siersma, Volkert;

    2004-01-01

    divergent models for TCR down-regulation and degradation have been suggested. The aims of this study were to determine the rate constants for constitutive and ligand-induced TCR degradation and to determine whether the TCR subunits segregate or are processed as an intact unit during TCR down-regulation and...

  8. Geodiversity and land degradation in Hungary

    Science.gov (United States)

    Őrsi, Anna

    2014-05-01

    Geodiversity represents a variety of natural values, but they are threatened by a series of anthropogenic activities and land degradation processes. Their effect depends on the intensity of the processes and the sensitivity of the area in question. As a consequence of land degradation processes not only biodiversity but also geodiversity can be damaged and deteriorated. The appearance of the natural landscape changes and natural processes may not have a decisive role in landscape development any more. Some of the damages are irreversible because fundamental changes happen in the landscape, or the processes having created the original forms are no longer in operation. Small scale land degradation processes may be reversible if nature is still capable of reproducing the original state. The most important land degradation processes are desertification and soil erosion. Mining, waste disposal, urbanisation and construction activities, agriculture, inaccurate forest and water management, tourism, unsuitable land use can also lead to severe land degradation problems. The objective of the paper is to show Hungarian examples to all land degradation processes that threaten geodiversity. The results will be shown on a series of maps showing land degradation processes endangering geodiversity in Hungary. A detailed analysis of smaller study sites will be provided to show the effects of certain land degradation processes on landform development and on the changes of geodiversity. This research is supported by the Hungarian Scientific Research Fund (OTKA), project Nr. 10875.

  9. Microbial Degradation of Indole and Its Derivatives

    Directory of Open Access Journals (Sweden)

    Pankaj Kumar Arora

    2015-01-01

    Full Text Available Indole and its derivatives, including 3-methylindole and 4-chloroindole, are environmental pollutants that are present worldwide. Microbial degradation of indole and its derivatives can occur in several aerobic and anaerobic pathways; these pathways involve different known and characterized genes. In this minireview, we summarize and explain the microbial degradation of indole, indole-3-acetic acid, 4-chloroindole, and methylindole.

  10. Solar maximum: solar array degradation

    International Nuclear Information System (INIS)

    The 5-year in-orbit power degradation of the silicon solar array aboard the Solar Maximum Satellite was evaluated. This was the first spacecraft to use Teflon R FEP as a coverglass adhesive, thus avoiding the necessity of an ultraviolet filter. The peak power tracking mode of the power regulator unit was employed to ensure consistent maximum power comparisons. Telemetry was normalized to account for the effects of illumination intensity, charged particle irradiation dosage, and solar array temperature. Reference conditions of 1.0 solar constant at air mass zero and 301 K (28 C) were used as a basis for normalization. Beginning-of-life array power was 2230 watts. Currently, the array output is 1830 watts. This corresponds to a 16 percent loss in array performance over 5 years. Comparison of Solar Maximum Telemetry and predicted power levels indicate that array output is 2 percent less than predictions based on an annual 1.0 MeV equivalent election fluence of 2.34 x ten to the 13th power square centimeters space environment

  11. Oxidative degradation of lignin, (2)

    International Nuclear Information System (INIS)

    Specifically 14C-labelled pine kraft lignin was oxidized with hydrogen peroxide and ferrous salts under various conditions. The reaction mixtures were applied to gell filtration on Sephadex G-15. The behavior of the specific carbon atoms in the reaction products was studied from the distribution of the radioactivity relative to that of molecular weight. The gaseous reaction products were separated and identified by gas chromatography, and the radioactivity of these products was measured. The results obtained are summarized as follows: 1. When a small amount of hydrogen peroxide was applied, a part of monomer compounds present in kraft waste liquor was condensed to give dimer and oligomer substances through the intermediate o-quinone. The amount of β- and R-carbon in the polymer fraction of kraft lignin in crased by mild oxidation treatment. 2. When a large amount of hydrogen peroxide was applied, the high molecular fraction of kraft lignin was considerably degraded to low molecular weight products. The ring rupture was remarkably observed. The β-carbon was retained in the high molecular fraction more firmly than other carbons even under severe oxidation conditions. 3. The gaseous reaction products identified were carbon dioxide, methane, acetylene + ethylene, ethane and propene. A large part of methoxyl carbon was converted into carbon dioxide and methane under the conditions described above. (author)

  12. Oxidative degradation of lignin, 1

    International Nuclear Information System (INIS)

    Specifically 14C-labelled pine kraft lignin was oxidized with alkaline hydrogen peroxide under various conditions. The reaction mixture was applied to gell filtration on Sephadex G-15. The behavior of the specific carbon atoms of the degraded lignin was studied from the distribution of radioactivity relative to that of molecular weight. No kraft lignin was decomposed to low molecular weight substances, but polymerized. The amount of alpha -, beta - and gamma -carbons of side chain and ring carbon in the polymer fraction was increased by the oxidation treatment. The amount of these carbon in the polymer fraction increased by increasing the amount of applied hydrogen peroxide. On the other hand, the amount of methoxyl carbon in the polymer fraction increased when a small amount of hydrogen peroxide was applied, and decreased when the amount of hydrogen peroxide was increased. The methoxyl carbon was eliminated to a large extent by treating with alkaline hydrogen peroxide, and a part of it was converted into methane. Ring rupture was not observed under these experimental conditions. (author)

  13. Exploring general gauge mediation

    International Nuclear Information System (INIS)

    We explore various aspects of General Gauge Mediation (GGM). We present a reformulation of the correlation functions used in GGM, and further elucidate their IR and UV properties. Additionally we clarify the issue of UV sensitivity in the calculation of the soft masses in the MSSM, highlighting the role of the supertrace over the messenger spectrum. Finally, we present weakly coupled messenger models which fully cover the parameter space of GGM. These examples demonstrate that the full parameter space of GGM is physical and realizable. Thus it should be considered a valid basis for future phenomenological explorations of gauge mediation.

  14. Degradation of multiwall carbon nanotubes by bacteria

    International Nuclear Information System (INIS)

    Understanding the environmental transformation of multiwall carbon nanotubes (MWCNTs) is important to their life cycle assessment and potential environmental impacts. We report that a bacterial community is capable of degrading 14C-labeled MWCNTs into 14CO2 in the presence of an external carbon source via co-metabolism. Multiple intermediate products were detected, and genotypic characterization revealed three possible microbial degraders: Burkholderia kururiensis, Delftia acidovorans, and Stenotrophomonas maltophilia. This result suggests that microbe/MWCNTs interaction may impact the long-term fate of MWCNTs. Highlights: •Mineralization of MWCNTs by a bacterial community was observed. •The mineralization required an external carbon source. •Multiple intermediate products were identified in the MWCNT degrading culture. •Three bacterial species were found likely responsible for MWCNT degradation. -- The 14C-labeled multiwall carbon nanotubes can be degraded to 14CO2 and other byproducts by a bacteria community under natural conditions

  15. Graceful Degradation of Air Traffic Operations

    CERN Document Server

    Gariel, Maxime

    2008-01-01

    The introduction of new technologies and concepts of operation in the air transportation system is not possible, unless they can be proven not to adversely affect the system operation under not only nominal, but also degraded conditions. In extreme scenarios, degraded operations due to partial or complete technological failures should never endanger system safety. Many past system evolutions, whether ground-based or airborne, have been based on trial-and-error, and system safety was addressed only after a specific event yielded dramatic or near- dramatic consequences. Future system evolutions, however, must leverage available computation, prior knowledge and abstract reasoning to anticipate all possible system degradations and prove that such degradations are graceful and safe. This paper is concerned with the graceful degradation of high-density, structured arrival traffic against partial or complete surveillance failures. It is shown that for equal performance requirements, some traffic configurations might...

  16. Degradation analysis of linear alkylbenzene sulfonates (LAS)

    Energy Technology Data Exchange (ETDEWEB)

    Sandhu, S.S.; Warren, W.J.; Reed, A.

    1980-01-01

    The degradation of mixtures of sodium salts of butyl-, decyl-, and dodecylbenzene sulfonate was studied as influenced by shaking for seven days, by the addition of soil and sand, and by changes in pH. LAS were analyzed by measurement of the absorbance at 223 nm or by reaction with methylene blue and measurement of the absorbance at 652 nm. Slurries containing 48.0 g/l. and 6.6 g/l. of LAS degraded at room temperature, which suggested a simple chemical decomposition of the LAS to simpler products since these concentrations prohibited microbial activity. None of the treatments significantly aided the degradation process, except the addition of soil, i.e., the addition of a source of microorganisms. Contrary to the LAS slurry data, the dodecylbenzene sulfonate solution did not degrade even after aging for 30 days; however, it degraded completely after 7 days on the addition of a glucose and nutrient solution.

  17. Near ultraviolet and postirradiation DNA degradation

    International Nuclear Information System (INIS)

    Possible effects of near ultraviolet radiation (near UV) on DNA degradation were examined. Postirradiation DNA degradation induced by ionizing radiation in strain Bsub(s-l) (uvr-, lex-) was shown to be inhibited by carbon monoxide (CO) and potassium cyanide (KCN) if the cells were grown on glycerol. Presumably the blockage of respiration by these agents lowered the amount of ATP in the cell. 50 kJ/m2 near UV did not simulate the action of CO and KCN, indicating that at this fluence the supply of ATP remains adequate for postirradiation DNA degradation. Near UV did not, itself, produce DNA degradation. In a strain (B/r) in which an inhibitor of postirradiation DNA degradation could be induced by both UV and ionizing radiation, near UV affected the inhibitor formation, whether administered before or after induction. (author)

  18. Structural and functional analysis of phytotoxin toxoflavin-degrading enzyme.

    Directory of Open Access Journals (Sweden)

    Woo-Suk Jung

    Full Text Available Pathogenic bacteria synthesize and secrete toxic low molecular weight compounds as virulence factors. These microbial toxins play essential roles in the pathogenicity of bacteria in various hosts, and are emerging as targets for antivirulence strategies. Toxoflavin, a phytotoxin produced by Burkholderia glumae BGR1, has been known to be the key factor in rice grain rot and wilt in many field crops. Recently, toxoflavin-degrading enzyme (TxDE was identified from Paenibacillus polymyxa JH2, thereby providing a possible antivirulence strategy for toxoflavin-mediated plant diseases. Here, we report the crystal structure of TxDE in the substrate-free form and in complex with toxoflavin, along with the results of a functional analysis. The overall structure of TxDE is similar to those of the vicinal oxygen chelate superfamily of metalloenzymes, despite the lack of apparent sequence identity. The active site is located at the end of the hydrophobic channel, 9 Å in length, and contains a Mn(II ion interacting with one histidine residue, two glutamate residues, and three water molecules in an octahedral coordination. In the complex, toxoflavin binds in the hydrophobic active site, specifically the Mn(II-coordination shell by replacing a ligating water molecule. A functional analysis indicated that TxDE catalyzes the degradation of toxoflavin in a manner dependent on oxygen, Mn(II, and the reducing agent dithiothreitol. These results provide the structural features of TxDE and the early events in catalysis.

  19. Degradation of azo dyes by environmental microorganisms and helminths

    Energy Technology Data Exchange (ETDEWEB)

    Kingthom Chung; Stevens, S.E. Jr. (Memphis State Univ., TN (United States). Dept. of Biology)

    1993-11-01

    The degradation of azo dyes by environmental microorganisms, fungi, and helminths is reviewed. Azo dyes are used in a wide variety of products and can be found in the effluent of most sewage treatment facilities. Substantial quantities of these dyes have been deposited in the environment, particularly in streams and rivers. Azo dyes were shown to affect microbial activities and microbial population sizes in the sediments and in the water columns of aquatic habitats. Only a few aerobic bacteria have been found to reduce azo dyes under aerobic conditions, and little is known about the process. A substantial number of anaerobic bacteria capable of azo dye reduction have been reported. The enzyme responsible for azo dye reduction has been partially purified, and characterization of the enzyme is proceeding. The nematode Ascaris lumbricoides and the cestode Moniezia expanza have been reported to reduce azo dyes anaerobically. Recently the fungus Phanerochaete chrysoporium was reported to mineralize azo dyes via a peroxidation-mediated pathway. A possible degradation pathway for the mineralization of azo dye is proposed and future research needs are discussed.

  20. Degradation of high density lipoprotein in cultured rat luteal cells

    International Nuclear Information System (INIS)

    In rat ovary luteal cells, degradation of high density lipoprotein (HDL) to tricholoracetic acid (TCA)-soluble products accounts for only a fraction of the HDL-derived cholesterol used for steroidogenesis. In this study the authors have investigated the fate of 125I]HDL bound to cultured luteal cells using pulse-chase technique. Luteal cell cultures were pulse labeled with [125I]HDL3 and reincubated in the absence of HDL. By 24 h about 50% of the initallay bound radioactivity was released into the medium, of which 60-65% could be precipitated with 10% TCA. Gel filtration of the chase incubation medium on 10% agarose showed that the amount of TCA-soluble radioactivity was nearly completely accounted for by a sharp peak in the low molecular weight region which was identified as 96% monoiodotyrosine by paper chromatography. The TCA-precipitable radioactivity was nearly completely accounted for by a sharp peak in the low molecular weight region which was identified as 96% monoiodotyrosine by paper chromatography. The TCA-precipitable radioactivity eluted over a wide range of molecular weights (15,000-80,000), and there was very little intact HDL present. Electrophoresis of the chase medium showed that component of the TCA-precipitable portion had mobility similar to apo AI. Lysosomal inhibitors of receptor-mediated endocytosis had no effect on the composition or quantity of radioactivity released during chase incubation. The results show that HDL3 binding to luteal cells is followed by complete degradation of the lipoprotein, although the TCA-soluble part does not reflect the extent of degradation

  1. Optineurin is an autophagy receptor for damaged mitochondria in parkin-mediated mitophagy that is disrupted by an ALS-linked mutation

    OpenAIRE

    Wong, Yvette C.; Holzbaur, Erika L.F.

    2014-01-01

    In mitophagy, damaged mitochondria recruit parkin to ubiquitinate proteins on the outer mitochondrial membrane, targeting mitochondria for autophagosome engulfment and degradation. However, the proteins involved in mediating autophagosome formation to degrade damaged and ubiquitinated mitochondria remain unknown. We used live cell imaging to demonstrate that optineurin is actively recruited to parkin-labeled ubiquitinated mitochondria and is stabilized by its ubiquitin binding domain. Optineu...

  2. Development of a functional food or drug against unloading-mediated muscle atrophy

    Science.gov (United States)

    Nikawa, Takeshi; Nakao, Reiko; Kagawa, Sachiko; Yamada, Chiharu; Abe, Manami; Tamura, Seiko; Kohno, Shohei; Sukeno, Akiko; Hirasaka, Katsuya; Okumura, Yuushi; Ishidoh, Kazumi

    The ubiquitin-proteasome pathway is a primary regulator of muscle protein turnover, providing a mechanism for selective degradation of regulatory and structural proteins. This pathway is constitutively active in muscle fibers and mediates both intracellular signaling events and normal muscle protein turnover. However, conditions of decreased muscle use, so called unloading, remarkably stimulate activity of this pathway, resulting in loss of muscle protein. In fact, we previously reported that expression of several ubiquitin ligase genes, such as MuRF-1, Cbl-b, and Siah-1A, which are rate-limiting enzymes of the ubiquitin-proteasome proteolytic pathway, are significantly up-regulated in rat skeletal muscle during spaceflight. Moreover, we found that Cbl-b-mediated ubiquitination and degradation of IRS-1, an important intermediates of IGF-1 signal transduction, contributes to muscle atrophy during unloading. Therefore, we hypothesized that inhibition of Cbl-b-mediated ubiquitination and degradation of IRS-1 leads to prevention of muscle atrophy during unloading. In this study, we aimed to evaluate oligopeptide as an inhibitor against ubiquitination of IRS-1 by Cbl-b. We synthesized various oligopeptides that may competitively inhibit the binding of Cbl-b to IRS-1 on the basis of their structures and screened inhibitory effects of these synthesized oligopeptides on Cbl-b-mediated ubiquitination of IRS-1 using in vitro ubiquitination systems. We found that two synthetic oligopeptides with specific amino acid sequences effectively inhibited interaction with Cbl-b and IRS-1, resulting in decreased ubiquitination and degradation of IRS-1 (Patent pending). In contrast, we also found inhibitory activity against Cbl-b-mediated ubiquitination of IRS-1 in soy protein-derived oligopeptides, whereas their inhibitory effects were weaker than those of synthetic oligopeptides. Our results suggest that specific oligopeptides may be available as a functional food against the muscle

  3. TRAIL sensitize MDR cells to MDR-related drugs by down-regulation of P-glycoprotein through inhibition of DNA-PKcs/Akt/GSK-3β pathway and activation of caspases

    Directory of Open Access Journals (Sweden)

    Kim Dong-Wan

    2010-07-01

    Full Text Available Abstract Background The development of new modulator possessing high efficacy, low toxicity and high selectivity is a pivotal approach to overcome P-glycoprotein (P-gp mediated multidrug resistance (MDR in cancer treatment. In this study, we suggest a new molecular mechanism that TRAIL (tumor necrosis factor-related apoptosis-inducing ligand down-regulates P-glycoprotein (P-gp through inhibition of DNA-PKcs/Akt/GSK-3β pathway and activation of caspases and thereby sensitize MDR cells to MDR-related drugs. Results MDR variants, CEM/VLB10-2, CEM/VLB55-8 and CEM/VLB100 cells, with gradually increased levels of P-gp derived from human lymphoblastic leukemia CEM cells, were gradually more susceptible to TRAIL-induced apoptosis and cytotoxicity than parental CEM cells. The P-gp level of MDR variants was positively correlated with the levels of DNA-PKcs, pAkt, pGSK-3β and c-Myc as well as DR5 and negatively correlated with the level of c-FLIPs. Hypersensitivity of CEM/VLB100 cells to TRAIL was accompanied by the activation of mitochondrial apoptotic pathway as well as the activation of initiator caspases. In addition, TRAIL-induced down-regulation of DNA-PKcs/Akt/GSK-3β pathway and c-FLIP and up-regulation of cell surface expression of death receptors were associated with the increased susceptibility to TRAIL of MDR cells. Moreover, TRAIL inhibited P-gp efflux function via caspase-3-dependent degradation of P-gp as well as DNA-PKcs and subsequently sensitized MDR cells to MDR-related drugs such as vinblastine and doxorubicin. We also found that suppression of DNA-PKcs by siRNA enhanced the susceptibility of MDR cells to vincristine as well as TRAIL via down-regulation of c-FLIP and P-gp expression and up-regulation of DR5. Conclusion This study showed for the first time that the MDR variant of CEM cells was hypersensitive to TRAIL due to up-regulation of DR5 and concomitant down-regulation of c-FLIP, and degradation of P-gp and DNA-PKcs by

  4. Axionic Mirage Mediation

    CERN Document Server

    Nakamura, Shuntaro; Yamaguchi, Masahiro

    2008-01-01

    Although the mirage mediation is one of the most plausible mediation mechanisms of supersymmetry breaking, it suffers from two crucial problems. One is the \\mu-/B \\mu-problem and the second is the cosmological one. The former stems from the fact that the B parameter tends to be comparable with the gravitino mass, which is two order of magnitude larger than the other soft masses. The latter problem is caused by the decay of the modulus whose branching ratio into the gravitino pair is sizable. In this paper, we propose a model of mirage mediation, in which Peccei-Quinn symmetry is incorporated. In this \\textit{axionic mirage mediation}, it is shown that the PQ symmetry breaking scale is dynamically determined around 10^{10-12} GeV due to the supersymmetry breaking effects, and the \\mu-problem can be solved naturally. Furthermore, in our model, the lightest supersymmetric particle (LSP) is the axino, that is the superpartner of the axion. The overabundance of the LSPs due to decays of modulus/gravitino, which is...

  5. Inflammatory mediators in osteoarthritis

    NARCIS (Netherlands)

    Beekhuizen, M.

    2014-01-01

    Osteoarthritis (OA) is a degenerative joint disorder involving cartilage destruction and joint inflammation. Despite extensive research, still much is unknown on the pathogenesis and aetiology of OA. Inflammation and inflammatory mediators (both local and systemic) are key in the pathogenesis of OA.

  6. Thermally favourable gauge mediation

    International Nuclear Information System (INIS)

    We discuss the thermal evolution of the spurion and messenger fields of ordinary gauge mediation models taking into account the Standard Model degrees of freedom. It is shown that for thermalized messengers the metastable susy breaking vacuum becomes thermally selected provided that the susy breaking sector is sufficiently weakly coupled to messengers or to any other observable field.

  7. Den sundhedsfremmende mediator

    DEFF Research Database (Denmark)

    Læssøe, Jeppe

    2009-01-01

    mediering samt mellem forskellige mediator-roller og tilhørsforhold. Det er også vigtigt at være bevidst om de centrale kvaliteter, risici og dilemmaer, som mediering indebærer i forhold til involvering af borgerne. Denne artikel rummer et bud på en sådan nuanceret begrebsliggørelse og refleksion, relateret...

  8. Bradykinin-mediated angioedema.

    Science.gov (United States)

    Obtułowicz, Krystyna

    2016-02-01

    Angioedema and urticaria often constitute a challenge in daily clinical practice. They may either co- -occur or present as independent conditions. They are characterized by a complex pathomechanism, and their symptoms may be triggered by diverse factors. These differences are crucial for developing a successful treatment regimen. Both conditions may have an allergic origin (immunoglobulin [Ig] E and non-IgE-related), usually induced by histamine, or a nonallergic one, such as bradykinin-mediated angioedema in patients with C1 inhibitor (C1-INH) deficiency or angioedema induced by certain drugs (eg, angiotensin-converting enzyme inhibitors). Currently, we distinguish 5 types of nonallergic angioedema: hereditary angioedema (HAE) due to C1-INH deficiency, acquired angioedema (AAE), and angioedema induced by the renin-angiotensin-aldosterone system, all of which are mediated by bradykinin, as well as pseudoallergic angioedema and idiopathic angioedema. Bradykinin-mediated angioedema (eg, laryngeal angioedema) may be life-threatening because of resistance to corticosteroids and antihistamine drugs. C1-INH concentrates are the drugs of choice in the treatment of HAE and AAE. In recent years, some new drugs have been introduced in the treatment of bradykinin-mediated angioedema, such as bradykinin B2-receptor antagonist, icatibant, and kallikrein inhibitor, ecallantide, which allow to improve treatment outcomes. PMID:26842379

  9. Degradation of triclocarban by a triclosan-degrading Sphingomonas sp. strain YL-JM2C.

    Science.gov (United States)

    Mulla, Sikandar I; Hu, Anyi; Wang, Yuwen; Sun, Qian; Huang, Shir-Ly; Wang, Han; Yu, Chang-Ping

    2016-02-01

    Bacterial degradation plays a vital role in determining the environmental fate of micropollutants like triclocarban. The mechanism of triclocarban degradation by pure bacterium is not yet explored. The purpose of this study was to identify metabolic pathway that might be involved in bacterial degradation of triclocarban. Triclosan-degrading Sphingomonas sp. strain YL-JM2C was first found to degrade up to 35% of triclocarban (4 mg L(-1)) within 5 d. Gas chromatography-mass spectrometry detected 3,4-dichloroaniline, 4-chloroaniline and 4-chlorocatechol as the major metabolites of the triclocarban degradation. Furthermore, total organic carbon results confirmed that the intermediates, 3,4-dichloroaniline (4 mg L(-1)) and 4-chloroaniline (4 mg L(-1)) could be degraded up to 77% and 80% by strain YL-JM2C within 5 d. PMID:26364219

  10. Degradation-by-design: Surface modification with functional substrates that enhance the enzymatic degradation of carbon nanotubes.

    Science.gov (United States)

    Sureshbabu, Adukamparai Rajukrishnan; Kurapati, Rajendra; Russier, Julie; Ménard-Moyon, Cécilia; Bartolini, Isacco; Meneghetti, Moreno; Kostarelos, Kostas; Bianco, Alberto

    2015-12-01

    Biodegradation of carbon-based nanomaterials has been pursued intensively in the last few years, as one of the most crucial issues for the design of safe, clinically relevant conjugates for biomedical applications. In this paper it is demonstrated that specific functional molecules can enhance the catalytic activity of horseradish peroxidase (HRP) and xanthine oxidase (XO) for the degradation of carbon nanotubes. Two different azido coumarins and one cathecol derivative are linked to multi-walled carbon nanotubes (MWCNTs). These molecules are good reducing substrates and strong redox mediators to enhance the catalytic activity of HRP. XO, known to metabolize various molecules mainly in the mammalian liver, including human, was instead used to test the biodegradability of MWCNTs modified with an azido purine. The products of the biodegradation process are characterized by transmission electron microscopy and Raman spectroscopy. The results indicate that coumarin and catechol moieties have enhanced the biodegradation of MWCNTs compared to oxidized nanotubes, likely due to the capacity of these substrates to better interact with and activate HRP. Although azido purine-MWCNTs are degraded less effectively by XO than oxidized nanotubes, the data uncover the importance of XO in the biodegradation of carbon-nanomaterials leading to their better surface engineering for biomedical applications. PMID:26342557

  11. Axionic mirage mediation

    International Nuclear Information System (INIS)

    Although mirage mediation is one of the most plausible mediation mechanisms of supersymmetry breaking, it suffers from two crucial problems. One is the μ/Bμ problem, and the second is the cosmological one. The former stems from the fact that the B parameter tends to be comparable with the gravitino mass, which is 2 orders of magnitude larger than the other soft masses. The latter problem is caused by the decay of the modulus whose branching ratio into the gravitino pair is sizable. In this paper, we propose a model of mirage mediation, in which Peccei-Quinn symmetry is incorporated. In this axionic mirage mediation, it is shown that the Peccei-Quinn symmetry breaking scale is dynamically determined around 1010 GeV to 1012 GeV due to the supersymmetry breaking effects, and the μ problem can be solved naturally. Furthermore, in our model, the lightest supersymmetric particle (LSP) is the axino, that is, the superpartner of the axion. The overabundance of the LSPs due to decays of the modulus/gravitino, which is the most serious cosmological difficulty in the mirage mediation, can be avoided if the axino is sufficiently light. The next-LSPs (NLSPs) produced by the gravitino decay eventually decay into the axino LSPs, yielding the dominant component of the axinos remaining today. It is shown that the axino with a mass of O(100) MeV is naturally realized, which can constitute the dark matter of the Universe, with a free-streaming length of the order of 0.1 Mpc. The saxion, the real scalar component of the axion supermultiplet, can also be cosmologically harmless due to the dilution of the modulus decay. The lifetime of the NLSP is relatively long, but much shorter than 1 sec, when the big-bang nucleosynthesis commences. The decay of the NLSP would provide intriguing collider signatures

  12. Proactive degradation management in complex systems

    International Nuclear Information System (INIS)

    Timely preventive maintenance is of great importance for safety equipment on NPP's. But preventive maintenance becomes complicated when we face systems in where these activities can be performed only during outage period and reactor shutdown must be executed in cause of safety related equipment failure during operation to perform corrective actions. For preventive maintenance strategy degradation monitoring is not always sufficient and degradation trending (extrapolation) should be performed to provide predictability of the extend of degradation and timely preventive or mitigative actions. Degradation trending in proactive maintenance case plays very important role. Current paper is devoted to the analysis and application of mathematical models to the degradation assessment of systems with dependent components. The main attention in present work was paid to the mathematical description of the degradation mechanism. Developed mathematical model allows assess and perform trending of degradation processes during various time moments. Methods can be applied for assessment of various risk estimates of hazardous systems such as systems at nuclear power plants. (author)

  13. Degradation of Soil Nutrients in Southeast China

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    A total of 2190 soil nutrient data in the Second National Soil Survey of China were collected to assess the degradation of soil nutrients in the hilly region of Southeast China. The definition of soil nutrient degradation is suggested firstly, then the evaluation criteria are set up and the current status of degradation of red soil and latosol is assessed. The percentages of areas in four grades of soil nutrient degradation, i.e., slightly deficient, medium deficient, severely deficient and extremely deficient, were 21.3%, 43.3%, 16.2% and 3.0% for soil total N; 0.7%, 6.4%, 16.7% and 76.2% for soil available P; and 25.4%, 26.3%, 8.6% and 5.0% for soil available K, respectively. The severity of soil nutrient degradation was in the order of P > N > K. The major factors leading to the degradation of soil nutrients in quantity include soil erosion, leaching and the consumption by crops. And the principal factor affecting the degradation of soil nutrients in availability is the fixation of N, P and K, especially the fixation of phosphorus. The average amount of P fixed by soils is 408 mg kg-1, and upland soils can fix more P than paddy soils.

  14. Prevention methods against hydrogen degradation of steel

    Directory of Open Access Journals (Sweden)

    J. Ćwiek

    2010-11-01

    Full Text Available Purpose: of this paper is presentation of mechanisms and forms of hydrogen degradation in steel along with pointing out methods for hydrogen degradation prevention.Design/methodology/approach: Hydrogen degradation of steel is a form of environmentally assisted failure which is caused by the action of hydrogen often in combination with residual or applied stress resulting in reduction of plasticity, load bearing capacity of a component, and cracking.Findings: The sources of hydrogen in steel were presented. Forms of hydrogen presence in metals, mechanisms of hydrogen degradation, and types of hydrogen induced damage were discussed in details. Five specific types of hydrogen induced damage to metals and alloys could be distinguished: hydrogen embrittlement, hydrogen-induced blistering, cracking from precipitation of internal hydrogen, hydrogen attack, cracking from hydride formation.Practical implications: Methods for hydrogen degradation prevention include: selection of suitable material, modifying environment to reduce hydrogen charging, and use of surface coatings and effective inhibitors.Originality/value: Originality the paper outlines the problem of hydrogen degradation of steel and other alloys, delivering knowledge to undertake preventive or remedial actions in order to avoid hydrogen induced degradation.

  15. Radiation degradation of alginate and chitosan

    Energy Technology Data Exchange (ETDEWEB)

    Nagasawa, Naotsugu; Mitomo, Hiroshi [Department of Biological and Chemical Engineering, Faculty of Engineering, Gunma University, Kiryu, Gunma (Japan); Yoshii, Fumio; Kume, Tamikazu [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment

    2000-03-01

    Alginate and chitosan were irradiated in solid or aqueous solution condition with Co{sup 60} gamma rays in the dose range of 20 to 500 kGy. Degradation was observed both in solid and solution conditions. The degradation in solution was remarkably greater than that in solid. For example, the molecular weight of alginate in 4%(w/v) solution decreased from 2 x 10{sup 5} for 0 kGy to 6 x 10{sup 3} for 50 kGy irradiation while the equivalent degradation by solid irradiation required 500 kGy. The activated species from irradiated water must be responsible for the degradation in solution. The degradation was also accompanied with the color change of alginate: the color became deep brown for highly degraded alginate. UV spectra showed a distinct absorption peak at 265 nm for colored alginates, increasing with dose. The fact that discoloration of colored alginate was caused on exposure to ozone suggests a formation of double bond in pyranose-ring by scission of glycosidic bond. Degradation behavior of chitosan in irradiation was almost the same as that of alginate. (author)

  16. Radiation degradation of alginate and chitosan

    International Nuclear Information System (INIS)

    Alginate and chitosan were irradiated in solid or aqueous solution condition with Co60 gamma rays in the dose range of 20 to 500 kGy. Degradation was observed both in solid and solution conditions. The degradation in solution was remarkably greater than that in solid. For example, the molecular weight of alginate in 4%(w/v) solution decreased from 2 x 105 for 0 kGy to 6 x 103 for 50 kGy irradiation while the equivalent degradation by solid irradiation required 500 kGy. The activated species from irradiated water must be responsible for the degradation in solution. The degradation was also accompanied with the color change of alginate: the color became deep brown for highly degraded alginate. UV spectra showed a distinct absorption peak at 265 nm for colored alginates, increasing with dose. The fact that discoloration of colored alginate was caused on exposure to ozone suggests a formation of double bond in pyranose-ring by scission of glycosidic bond. Degradation behavior of chitosan in irradiation was almost the same as that of alginate. (author)

  17. PCGF2 negatively regulates arsenic trioxide-induced PML-RARA protein degradation via UBE2I inhibition in NB4 cells.

    Science.gov (United States)

    Jo, Sungsin; Lee, Young Lim; Kim, Sojin; Lee, Hongki; Chung, Heekyoung

    2016-07-01

    Arsenic trioxide (ATO) is a therapeutic agent for acute promyelocytic leukemia (APL) which induces PML-RARA protein degradation via enhanced UBE2I-mediated sumoylation. PCGF2, a Polycomb group protein, has been suggested as an anti-SUMO E3 protein by inhibiting the sumoylation of UBE2I substrates, HSF2 and RANGAP1, via direct interaction. Thus, we hypothesized that PCGF2 might play a role in ATO-induced PML-RARA degradation by interacting with UBE2I. PCGF2 protein was down-regulated upon ATO treatment in human APL cell line, NB4. Knockdown of PCGF2 in NB4 cells, in the absence of ATO treatment, was sufficient to induce sumoylation-, ubiquitylation- and PML nuclear body-mediated degradation of PML-RARA protein. Moreover, overexpression of PCGF2 protected ATO-mediated degradation of ectopic and endogenous PML-RARA in 293T and NB4 cells, respectively. In 293T cells, UBE2I-mediated PML-RARA degradation was reduced upon PCGF2 co-expression. In addition, UBE2I-mediated sumoylation of PML-RARA was reduced upon PCGF2 co-expression and PCGF2-UBE2I interaction was confirmed by co-immunoprecipitation. Likewise, endogenous PCGF2-UBE2I interaction was detected by co-immunoprecipitation and immunofluorescence assays in NB4 cells. Intriguingly, upon ATO-treatment, such interaction was disrupted and UBE2I was co-immunoprecipitated or co-localized with its SUMO substrate, PML-RARA. Taken together, our results suggested a novel role of PCGF2 in ATO-mediated degradation of PML-RARA that PCGF2 might act as a negative regulator of UBE2I via direct interaction. PMID:27030546

  18. The Hsp110 molecular chaperone stabilizes apolipoprotein B from endoplasmic reticulum-associated degradation (ERAD).

    Science.gov (United States)

    Hrizo, Stacy L; Gusarova, Viktoria; Habiel, David M; Goeckeler, Jennifer L; Fisher, Edward A; Brodsky, Jeffrey L

    2007-11-01

    Apolipoprotein B (apoB) is the most abundant protein in low density lipoproteins and plays key roles in cholesterol homeostasis. The co-translational degradation of apoB is controlled by fatty acid levels in the endoplasmic reticulum (ER) and is mediated by the proteasome. To define the mechanism of apoB degradation, we employed a cell-free system in which proteasome-dependent degradation is recapitulated with yeast cytosol, and we developed an apoB yeast expression system. We discovered that a yeast Hsp110, Sse1p, associates with and stabilizes apoB, which contrasts with data indicating that select Hsp70s and Hsp90s facilitate apoB degradation. However, the Ssb Hsp70 chaperones have no effect on apoB turnover. To determine whether our results are relevant in mammalian cells, Hsp110 was overexpressed in hepatocytes, and enhanced apoB secretion was observed. This study indicates that chaperones within distinct complexes can play unique roles during ER-associated degradation (ERAD), establishes a role for Sse1/Hsp110 in ERAD, and identifies Hsp110 as a target to lower cholesterol. PMID:17823116

  19. Pathogenic prion protein is degraded by a manganese oxide mineral found in soils

    Science.gov (United States)

    Russo, F.; Johnson, C.J.; McKenzie, D.; Aiken, Judd M.; Pedersen, J.A.

    2009-01-01

    Prions, the aetiological agents of transmissible spongiform encephalopathies, exhibit extreme resistance to degradation. Soil can retain prion infectivity in the environment for years. Reactive soil components may, however, contribute to the inactivation of prions in soil. Members of the birnessite family of manganese oxides (MnO2) rank among the strongest natural oxidants in soils. Here, we report the abiotic degradation of pathogenic prion protein (PrPTSE) by a synthetic analogue of naturally occurring birnessite minerals. Aqueous MnO2 suspensions degraded the PrPTSE as evidenced by decreased immunoreactivity and diminished ability to seed protein misfolding cyclic amplification reactions. Birnessite-mediated PrPTSE degradation increased as a solution's pH decreased, consistent with the pH-dependence of the redox potential of MnO2. Exposure to 5.6 mg MnO2 ml-1 (PrPTSE:MnO2=1 : 110) decreased PrPTSE levels by ???4 orders of magnitude. Manganese oxides may contribute to prion degradation in soil environments rich in these minerals. ?? 2009 SGM.

  20. Degradation of phospholipids by oxidative stress--exceptional significance of cardiolipin.

    Science.gov (United States)

    Wiswedel, Ingrid; Gardemann, Andreas; Storch, Andreas; Peter, Daniela; Schild, Lorenz

    2010-02-01

    The aim of this study was to investigate the effect of oxidative stress on mitochondrial phospholipids. In this context, this study investigated (i) the content of phosphatidylethanolamine (PE), phosphatidylcholine (PC) and cardiolipin (CL), (ii) the correlation of CL degradation with mitochondrial function and (iii) the correlation of CL degradation and CL oxidation. Oxidative stress induced by iron/ascorbate caused a dramatic decrease of these phospholipids, in which CL was the most sensitive phospholipid. Even moderate oxidative stress by hypoxia/reoxygenation caused a decrease in CL that was parallelled by a decrease in active respiration of isolated rat heart mitochondria. The relation between oxidative stress, CL degradation and CL oxidation was studied by in vitro treatment of commercially available CL with superoxide anion radicals and H2O2. The degradation of CL was mediated by H2O2 and required the presence of cytochrome c. Other peroxidases such as horse radish peroxidase and glutathione peroxidase had no effect. Cytochrome c in the presence of H2O2 caused CL oxidation. The data demonstrate that oxidative stress may cause degradation of phospholipids by oxidation, in particular CL; resulting in mitochondrial dysfunction. PMID:20092032

  1. Ferristatin II promotes degradation of transferrin receptor-1 in vitro and in vivo.

    Directory of Open Access Journals (Sweden)

    Shaina L Byrne

    Full Text Available Previous studies have shown that the small molecule iron transport inhibitor ferristatin (NSC30611 acts by down-regulating transferrin receptor-1 (TfR1 via receptor degradation. In this investigation, we show that another small molecule, ferristatin II (NSC8679, acts in a similar manner to degrade the receptor through a nystatin-sensitive lipid raft pathway. Structural domains of the receptor necessary for interactions with the clathrin pathway do not appear to be necessary for ferristatin II induced degradation of TfR1. While TfR1 constitutively traffics through clathrin-mediated endocytosis, with or without ligand, the presence of Tf blocked ferristatin II induced degradation of TfR1. This effect of Tf was lost in a ligand binding receptor mutant G647A TfR1, suggesting that Tf binding to its receptor interferes with the drug's activity. Rats treated with ferristatin II have lower TfR1 in liver. These effects are associated with reduced intestinal (59Fe uptake, lower serum iron and transferrin saturation, but no change in liver non-heme iron stores. The observed hypoferremia promoted by degradation of TfR1 by ferristatin II appears to be due to induced hepcidin gene expression.

  2. Conductive iron oxide minerals accelerate syntrophic cooperation in methanogenic benzoate degradation

    International Nuclear Information System (INIS)

    Highlights: • Paddy soil contaminated with benzoate incubated with hematite and magnetite. • Iron oxides addition enhanced methanogenic benzoate degradation by 25–53%. • The facilitated syntrophy might involve direct interspecies electron transfer. • Bacillaceae, Peptococcaceae, and Methanobacterium are potentially involved. - Abstract: Recent studies have suggested that conductive iron oxide minerals can facilitate syntrophic metabolism of the methanogenic degradation of organic matter, such as ethanol, propionate and butyrate, in natural and engineered microbial ecosystems. This enhanced syntrophy involves direct interspecies electron transfer (DIET) powered by microorganisms exchanging metabolic electrons through electrically conductive minerals. Here, we evaluated the possibility that conductive iron oxides (hematite and magnetite) can stimulate the methanogenic degradation of benzoate, which is a common intermediate in the anaerobic metabolism of aromatic compounds. The results showed that 89–94% of the electrons released from benzoate oxidation were recovered in CH4 production, and acetate was identified as the only carbon-bearing intermediate during benzoate degradation. Compared with the iron-free controls, the rates of methanogenic benzoate degradation were enhanced by 25% and 53% in the presence of hematite and magnetite, respectively. This stimulatory effect probably resulted from DIET-mediated methanogenesis in which electrons transfer between syntrophic partners via conductive iron minerals. Phylogenetic analyses revealed that Bacillaceae, Peptococcaceae, and Methanobacterium are potentially involved in the functioning of syntrophic DIET. Considering the ubiquitous presence of iron minerals within soils and sediments, the findings of this study will increase the current understanding of the natural biological attenuation of aromatic hydrocarbons in anaerobic environments

  3. Photocatalytic degradation of trichloroethylene in aqueous phase using nano-ZNO/Laponite composites.

    Science.gov (United States)

    Joo, Jin Chul; Ahn, Chang Hyuk; Jang, Dae Gyu; Yoon, Young Han; Kim, Jong Kyu; Campos, Luiza; Ahn, Hosang

    2013-12-15

    The feasibility of nano-ZnO/Laponite composites (NZLc) as a valid alternative to TiO2 to mineralize trichloroethylene (TCE) without difficulties for recovery of photocatalysts was evaluated. Based on the experimental observations, the removal of TCE using NZLc under UV irradiation was multiple reaction processes (i.e., sorption, photolysis, and photocatalysis). Sorption of TCE was thermodynamically favorable due to the hydrophobic partitioning into crosslinked poly vinyl alcohol, and the adsorption onto high-surface-area mineral surfaces of both ZnO and Laponite. The degradation efficiency of TCE can be significantly improved using NZLc under UV irradiation, indicating that ZnO-mediated heterogeneous photocatalytic degradation occurred. However, the degradation efficiency was found to vary with experimental conditions (e.g., initial concentration of TCE, loading amount of NZLc, the intensity of light and initial solution pH). Although the removal of TCE by NZLc was found to be a complex function of sorption, photolysis, and photocatalysis, the photocatalytic degradation of TCE on the surface of ZnO was critical. Consequently, developed NZLc can be applied as a valid alternative to suspended TiO2 powder, and overcome drawbacks (e.g., filtration and recovery of photocatalysts) in degradation of TCE for various water resources. PMID:24239256

  4. Arkadia, a novel SUMO-targeted ubiquitin ligase involved in PML degradation.

    Science.gov (United States)

    Erker, Yigit; Neyret-Kahn, Helene; Seeler, Jacob S; Dejean, Anne; Atfi, Azeddine; Levy, Laurence

    2013-06-01

    Arkadia is a RING domain E3 ubiquitin ligase that activates the transforming growth factor β (TGF-β) pathway by inducing degradation of the inhibitor SnoN/Ski. Here we show that Arkadia contains three successive SUMO-interacting motifs (SIMs) that mediate noncovalent interaction with poly-SUMO2. We identify the third SIM (VVDL) of Arkadia to be the most relevant one in this interaction. Furthermore, we provide evidence that Arkadia can function as a SUMO-targeted ubiquitin ligase (STUBL) by ubiquitinating SUMO chains. While the SIMs of Arkadia are not essential for SnoN/Ski degradation in response to TGF-β, we show that they are necessary for the interaction of Arkadia with polysumoylated PML in response to arsenic and its concomitant accumulation into PML nuclear bodies. Moreover, Arkadia depletion leads to accumulation of polysumoylated PML in response to arsenic, highlighting a requirement of Arkadia for arsenic-induced degradation of polysumoylated PML. Interestingly, Arkadia homodimerizes but does not heterodimerize with RNF4, the other STUBL involved in PML degradation, suggesting that these two E3 ligases do not act synergistically but most probably act independently during this process. Altogether, these results identify Arkadia to be a novel STUBL that can trigger degradation of signal-induced polysumoylated proteins. PMID:23530056

  5. Identification of factors involved in target RNA-directed microRNA degradation.

    Science.gov (United States)

    Haas, Gabrielle; Cetin, Semih; Messmer, Mélanie; Chane-Woon-Ming, Béatrice; Terenzi, Olivier; Chicher, Johana; Kuhn, Lauriane; Hammann, Philippe; Pfeffer, Sébastien

    2016-04-01

    The mechanism by which micro (mi)RNAs control their target gene expression is now well understood. It is however less clear how the level of miRNAs themselves is regulated. Under specific conditions, abundant and highly complementary target RNA can trigger miRNA degradation by a mechanism involving nucleotide addition and exonucleolytic degradation. One such mechanism has been previously observed to occur naturally during viral infection. To date, the molecular details of this phenomenon are not known. We report here that both the degree of complementarity and the ratio of miRNA/target abundance are crucial for the efficient decay of the small RNA. Using a proteomic approach based on the transfection of biotinylated antimiRNA oligonucleotides, we set to identify the factors involved in target-mediated miRNA degradation. Among the retrieved proteins, we identified members of the RNA-induced silencing complex, but also RNA modifying and degradation enzymes. We further validate and characterize the importance of one of these, the Perlman Syndrome 3'-5' exonuclease DIS3L2. We show that this protein interacts with Argonaute 2 and functionally validate its role in target-directed miRNA degradation both by artificial targets and in the context of mouse cytomegalovirus infection. PMID:26809675

  6. Autonomous valve for detection of biopolymer degradation

    DEFF Research Database (Denmark)

    Keller, Stephan Urs; Noeth, Nadine-Nicole; Fetz, Stefanie; Grünefeld, Marco; Geschke, Oliver; Boisen, Anja; Haefliger, D.

    We present a polymer microvalve that allows the detection of biopolymer degradation without the need of external energy. The valve is based on a polymer container filled with a colored marker solution and closed by a thin lid. This structure is covered by a film of poly(L-lactide) and degradation...... of the biopolymer triggers the release of the color which is detected visually. The autonomous valve has potential for the fast testing of biopolymer degradation under various environmental conditions or by specific enzymes....

  7. Radiation degradation of short-cotton linters

    International Nuclear Information System (INIS)

    Radiation degradation of short-cotton linters has been studied by using X-ray diffraction, an infrared spectrometer and a viscosimeter. Average molecular weight and crystallinity of short-cotton linters and the change of reducing sugar in γ-radiation degradation were examined. It was found that cellulosic saccharification in hydrolysis was enhanced with preirradiation of linters. This probably resulted from the radiation induced change of cellulosic structure. Sensitizers to promote radiation degradation effect were investigated. Carbon tetrachloride has been found to be effective. (author)

  8. CHANNEL WIDENING DURING DEGRADATION OF ALLUVIAL RIVERS

    Institute of Scientific and Technical Information of China (English)

    Guangqian WANG; Junqiang XIA

    2001-01-01

    This paper first describes the phenomenon of channel widening during degradation of alluvial rivers,explains the mechanisms of channel widening, and analyzes the stability of cohesive riverbank. Then a one-dimensional mathematical model is developed to simulate the transport of non-uniform suspended sediments, with a sub-model for the simulation of channel widening, and is used to study the process of channel widening during degradation. The effects of different incident flow and sediment conditions and different riverbank material characteristics on channel widening and bed degradation are compared.Finally, main factors that control the deformation processes are identified.

  9. Stability and Degradation of Polymer Solar cells

    DEFF Research Database (Denmark)

    Norrman, Kion

    The current state-of-the-art allows for roll-to-roll manufacture of polymer solar cells in high volume with stability and efficiency sufficient to grant success in low-energy applications. However, further improvement is needed for the successful application of the devices in real life applications...... chemical degradation mechanisms are currently scarce. An overview of known degradation mechanisms will be presented and discussed in relation to state-of-the-art methodologies to study failure mechanisms with focus on chemical degradation....

  10. Microfluidic Assessment of Frying Oil Degradation

    Science.gov (United States)

    Liu, Mei; Xie, Shaorong; Ge, Ji; Xu, Zhensong; Wu, Zhizheng; Ru, Changhai; Luo, Jun; Sun, Yu

    2016-06-01

    Monitoring the quality of frying oil is important for the health of consumers. This paper reports a microfluidic technique for rapidly quantifying the degradation of frying oil. The microfluidic device generates monodispersed water-in-oil droplets and exploits viscosity and interfacial tension changes of frying oil samples over their frying/degradation process. The measured parameters were correlated to the total polar material percentage that is widely used in the food industry. The results reveal that the steady-state length of droplets can be used for unambiguously assessing frying oil quality degradation.

  11. Microfluidic Assessment of Frying Oil Degradation

    Science.gov (United States)

    Liu, Mei; Xie, Shaorong; Ge, Ji; Xu, Zhensong; Wu, Zhizheng; Ru, Changhai; Luo, Jun; Sun, Yu

    2016-01-01

    Monitoring the quality of frying oil is important for the health of consumers. This paper reports a microfluidic technique for rapidly quantifying the degradation of frying oil. The microfluidic device generates monodispersed water-in-oil droplets and exploits viscosity and interfacial tension changes of frying oil samples over their frying/degradation process. The measured parameters were correlated to the total polar material percentage that is widely used in the food industry. The results reveal that the steady-state length of droplets can be used for unambiguously assessing frying oil quality degradation. PMID:27312884

  12. Rising population and environmental degradation.

    Science.gov (United States)

    Mitra, A

    Environmental degradation is becoming an increasingly ominous threat to the well-being of India's population, and excessive population growth is the primary cause of environmental deterioration. Population growth increases the need to produce consumer products and this need, in turn, intensifies the trend to over-exploit and misuse environmental resources. Efforts to control population growth through contraceptive technology and the expansion of family planning services and to control environmental deterioration via technology and management will meet with little success. A prerequisite for controlling these dual problems is the improvement of living conditions for the masses. Only when individuals acquire a sense of security and have the prospect of acquiring a share in the resources of the country will they be willing to conserve and renew resources and to limit their fertility. Viewed from this prospective, various factors and trends in India can be assessed as either negative or positive. Positive factors, i.e., those which enhance economic oppotunities and security for the general population, include the recent achievement of economic grothw in the country's agricultural and industrial sectors, the growth in technological knowledge, and the expansion of the rural and urban infrastructure. Negative factors include 1) the increase in income inequality, 2) the refusal to grant distributive justice to the masses, 3) the lack of education which impedes public understanding and awareness of environmental issues and promotes under utilization of community and social services, 4) the high unemployment rate which prevents individuals from developing a sense of responsibility and self respect; and 5) the refusal of the government to establish fuel policies to halt the growing problem of deforestation. Major environmental problems include pollution and congestion associated with the geographical concentration of industry; the destruction of the forests which leads to

  13. Programmed hydrolysis of nanoassemblies by electrostatic interaction-mediated enzymatic-degradation†

    OpenAIRE

    Samarajeewa, Sandani; Zentay, Ryan P.; Jhurry, Nema D.; Li, Ang; Seetho, Kellie; Zou, Jiong; Wooley, Karen L.

    2014-01-01

    Electrostatic interaction-mediated enzymatic-hydrolysis of poly(lactide)-containing nanoscale assemblies is described. At physiological pH, degradable core–shell morphologies with charged shells can readily attract or repel enzymes carrying opposite or similar charges, respectively.

  14. Downregulation of adenosine and P2X receptor-mediated cardiovascular responses in heart failure rats

    DEFF Research Database (Denmark)

    Zhao, Xin; Sun, X Y; Erlinge, D;

    2000-01-01

    degradation product adenosine, experiments were performed in a rat model of ischaemic CHF. In this model, ischaemia was induced in rats by ligation of the left coronary artery. Our results demonstrate that there is a selective downregulation of P2X receptor-mediated pressor effects, while the hypotensive...

  15. Mediation Analysis with Principal Stratification

    OpenAIRE

    Gallop, Robert; Small, Dylan; Lin, Julia Y.; Elliot, Michael R.; Joffe, Marshall; Ten Have, Thomas R.

    2009-01-01

    In assessing the mechanism of treatment efficacy in randomized clinical trials, investigators often perform mediation analyses by analyzing if the significant intent-to-treat treatment effect on outcome occurs through or around a third intermediate or mediating variable: indirect and direct effects, respectively. Standard mediation analyses assume sequential ignorability, i.e., conditional on covariates the intermediate or mediating factor is randomly assigned, as is the treatment in a random...

  16. Protein degradation and protein synthesis in long-term memory formation

    Directory of Open Access Journals (Sweden)

    Timothy J Jarome

    2014-06-01

    Full Text Available Long-term memory (LTM formation requires transient changes in the activity of intracellular signaling cascades that are thought to regulate new gene transcription and de novo protein synthesis in the brain. Consistent with this, protein synthesis inhibitors impair LTM for a variety of behavioral tasks when infused into the brain around the time of training or following memory retrieval, suggesting that protein synthesis is a critical step in LTM storage in the brain. However, evidence suggests that protein degradation mediated by the ubiquitin-proteasome system may also be a critical regulator of LTM formation and stability following retrieval. This requirement for increased protein degradation has been shown in the same brain regions in which protein synthesis is required for LTM storage. Additionally, increases in the phosphorylation of proteins involved in translational control parallel increases in protein polyubiquitination and the increased demand for protein degradation is regulated by intracellular signaling molecules thought to regulate protein synthesis during LTM formation. In some cases inhibiting proteasome activity can rescue memory impairments that result from pharmacological blockade of protein synthesis, suggesting that protein degradation may control the requirement for protein synthesis during the memory storage process. Results such as these suggest that protein degradation and synthesis are both critical for LTM formation and may interact to properly consolidate and store memories in the brain. Here, we review the evidence implicating protein synthesis and degradation in LTM storage and highlight the areas of overlap between these two opposing processes. We also discuss evidence suggesting these two processes may interact to properly form and store memories. LTM storage likely requires a coordinated regulation between protein degradation and synthesis at multiple sites in the mammalian brain.

  17. Ubiquitination of inducible nitric oxide synthase is required for its degradation

    Science.gov (United States)

    Kolodziejski, Pawel J.; Musial, Aleksandra; Koo, Ja-Seok; Eissa, N. Tony

    2002-01-01

    Inducible nitric oxide synthase (iNOS) is responsible for nitric oxide (NO) synthesis from l-arginine in response to inflammatory mediators. We have previously shown that iNOS is degraded through the 26S proteasome. Targeting of proteins for proteasomal degradation may or may not require their covalent linkage to multiubiquitin chains (ubiquitination). In addition, ubiquitination of a protein can serve functions other than signaling proteolysis. In this context, it is not known whether iNOS is subject to ubiquitination or whether ubiquitination is required for its degradation. In this study, we show that iNOS, expressed in HEK293 cells or induced in primary bronchial epithelial cells, A549 cells, or murine macrophages, is subject to ubiquitination. To investigate whether iNOS ubiquitination is required for its degradation, HEK293T cells were cotransfected with plasmids containing cDNAs of human iNOS and of the dominant negative ubiquitin mutant K48R. Disruption of ubiquitination by K48R ubiquitin resulted in inhibition of iNOS degradation. ts20 is a mutant cell line that contains a thermolabile ubiquitin-activating enzyme (E1) that is inactivated at elevated temperature, preventing ubiquitination. Incubation of ts20 cells, stably expressing human iNOS, at the nonpermissive temperature (40°C) resulted in inhibition of iNOS degradation and marked accumulation of iNOS. These studies indicate that iNOS is subject to ubiquitination and that ubiquitination is required for its degradation. PMID:12221289

  18. Tumor Necrosis Factor-α Induces RelA Degradation via Ubiquitination at Lysine 195 to Prevent Excessive Nuclear Factor-κB Activation*

    OpenAIRE

    Fan, Yihui; Mao, Renfang; Zhao, Yanling; Yu, Yang; Sun, WenJing; Song, Ping; Shi, Zhongcheng; Zhang, Dekai; Yvon, Eric; Zhang, Hong; Fu, Songbin; Yang, Jianhua

    2009-01-01

    Ubiquitination-mediated degradation of the RelA subunit of nuclear factor-κB (NF-κB) is critical for the termination of NF-κB activation. However, the precise mechanism for the ubiquitination of RelA is still not fully understood. Here we report that tumor necrosis factor-α (TNFα) induces RelA polyubiquitination at the lysine 195 residue, and this ubiquitination event is critical for the degradation of RelA and termination of TNFα-mediated NF-κB activation. Overexpression of a RelA mutant wit...

  19. Carbon capture and sequestration: an exploratory inhalation toxicity assessment of amine-trapping solvents and their degradation products.

    Science.gov (United States)

    McDonald, Jacob D; Kracko, Dean; Doyle-Eisele, Melanie; Garner, C Edwin; Wegerski, Chris; Senft, Al; Knipping, Eladio; Shaw, Stephanie; Rohr, Annette

    2014-09-16

    Carbon dioxide (CO2) absorption with aqueous amine solvents is a method of carbon capture and sequestration (CCS) from flue gases. One concern is the possible release of amine solvents and degradation products into the atmosphere, warranting evaluation of potential pulmonary effects from inhalation. The CCS amines monoethanolamine (MEA), methyldiethanolamine (MDEA), and piperazine (PIP) underwent oxidative and CO2-mediated degradation for 75 days. C57bl/6N mice were exposed for 7 days by inhalation of 25 ppm neat amine or equivalant concentration in the degraded mixture. The aqueous solutions were nebulized to create the inhalation atmospheres. Pulmonary response was measured by changes in inflammatory cells in bronchoalveolar lavage fluid and cytokine expression in lung tissue. Ames mutagenicity and CHO-K1 micronucleus assays were applied to assess genotoxicity. Chemical analysis of the test atmosphere and liquid revealed complex mixtures, including acids, aldehydes, and other compounds. Exposure to oxidatively degraded MEA increased (p oxidative stress. CO2 degradation resulted in a different composition, less degradation, and lower observed toxicity (less magnitude and number of effects) with no genotoxicity. Overall, oxidative degradation of the amines studied resulted in enhanced toxicity (increased magnitude and number of effects) compared to the neat chemicals. PMID:25167095

  20. Molecular modeling approach to explore the role of cathepsin B from Hordeum vulgare in the degradation of Aβ peptides.

    Science.gov (United States)

    Dhanavade, Maruti J; Parulekar, Rishikesh S; Kamble, Subodh A; Sonawane, Kailas D

    2016-01-01

    The pathological hallmark of Alzheimer's disease is the accumulation of Aβ peptides in human brains. These Aβ peptides can be degraded by several enzymes such as hACE, hECE, hIDE and cathepsin B. Out of which cathepsin B also belongs to the papain super family and has been found in human brains, it has a role in Aβ peptide degradation through limited proteolysis. The Aβ concentrations are maintained properly by its production and clearance via receptor-mediated cellular uptake and direct enzymatic degradation. However, the reduced production of Aβ degrading enzymes as well as their Aβ degrading activity in human brains initiate the process of accumulation of Aβ peptides. So it becomes essential to investigate the molecular interactions involved in the process of Aβ degradation in detail at the atomic level. Hence, homology modeling, molecular docking and molecular dynamics simulation techniques have been used to explore the possible role of cathepsin B from Hordeum vulgare in the degradation of amyloid beta (Aβ) peptides. The homology model of cathepsin B from Hordeum vulgare shows good similarity with human cathepsin B. Molecular docking and MD simulation results revealed that the active site residues Cys32, HIS112, HIS113 are involved in the catalytic activity of cathepsin B. The sulfhydryl group of the Cys32 residue of cathepsin B from Hordeum vulgare cleaves the Aβ peptide from the carboxylic end of Glu11. Hence, this structural study might be helpful in designing alternative strategies for the treatment of AD. PMID:26568474