Objective To investigate the effect of mucin 1(MUC1)on the proliferation and apoptosis of nasopharyngeal carcinoma(NPC)and its regulatory mechanism.Methods The 60 NPC and paired para-cancer normal tissues were collect...Objective To investigate the effect of mucin 1(MUC1)on the proliferation and apoptosis of nasopharyngeal carcinoma(NPC)and its regulatory mechanism.Methods The 60 NPC and paired para-cancer normal tissues were collected from October 2020 to July 2021 in Quanzhou First Hospital.The expression of MUC1 was measured by real-time quantitative PCR(qPCR)in the patients with PNC.The 5-8F and HNE1 cells were transfected with siRNA control(si-control)or siRNA targeting MUC1(si-MUC1).Cell proliferation was analyzed by cell counting kit-8 and colony formation assay,and apoptosis was analyzed by flow cytometry analysis in the 5-8F and HNE1 cells.The qPCR and ELISA were executed to analyze the levels of TNF-αand IL-6.Western blot was performed to measure the expression of MUC1,NFкB and apoptosis-related proteins(Bax and Bcl-2).Results The expression of MUC1 was up-regulated in the NPC tissues,and NPC patients with the high MUC1 expression were inclined to EBV infection,growth and metastasis of NPC.Loss of MUC1 restrained malignant features,including the proliferation and apoptosis,downregulated the expression of p-IкB、p-P65 and Bcl-2 and upregulated the expression of Bax in the NPC cells.Conclusion Downregulation of MUC1 restrained biological characteristics of malignancy,including cell proliferation and apoptosis,by inactivating NF-κB signaling pathway in NPC.展开更多
S-RNase-mediated gametophytic self-incompatibility (GSI) is controlled by a multiallelic S-locus at which two separate genes, the female (pistil) and male (pollen) specificity determinants, are tightly linked. T...S-RNase-mediated gametophytic self-incompatibility (GSI) is controlled by a multiallelic S-locus at which two separate genes, the female (pistil) and male (pollen) specificity determinants, are tightly linked. This review described both the identification of pollen specific F-box genes, SLF/SFBs, in Antirrhinum, Petunia and Prunus species and the demonstration of SLF/SFB as pollen determinant together with their functions in GSI response. Recent studies of how the pollen determinant functions in pollination reaction revealed that pollen determinant interacted with S-RNases in a non-allele-specific manner. It targeted all of the non-self S-RNases for ubiquitination through a functional SCF complex and subsequent degradation via 26S proteasome pathway in compatible reaction. It allows pollen tube to reach into the embryo sac and to finish double fertilization. In incompatible response, the intact self S-RNases were left to function as a cytotoxin that degrades self-pollen tube RNA, resulting in the cessation of pollen tube growth.展开更多
Steroids function as signaling molecules in both animals and plants. While animal steroid hormones are perceived by nuclear receptor family of transcription factors, brassinosteroids (BR) in plants are perceived by ...Steroids function as signaling molecules in both animals and plants. While animal steroid hormones are perceived by nuclear receptor family of transcription factors, brassinosteroids (BR) in plants are perceived by a cell surface receptor kinase, BRI 1. Recent studies have demonstrated that BR binding to the extracellular domain of BRI 1 induces kinase activation and dimerization with another receptor kinase, BAKI. Activated BRI 1 or BAKI then regulate, possibly indirectly, the activities of BIN2 kinase and/or BSU 1 phosphatase, which directly regulate the phosphorylation status and nuclear accumulation of two homologous transcription factors, BZRI and BES 1. BZRI and BES 1 directly bind to promoters of BR responsive genes to regulate their expression. The BR signaling pathway has become a paradigm for both receptor kinase signaling in plants and steroid signaling by cell surface receptors in general.展开更多
Gap junctions, consisting of connexins, allow the exchange of small molecules (<1 kD) between adjacent cells, thusproviding a mechanism for synchronizing the responses of groups of cells to environmental stimuli. C...Gap junctions, consisting of connexins, allow the exchange of small molecules (<1 kD) between adjacent cells, thusproviding a mechanism for synchronizing the responses of groups of cells to environmental stimuli. Connexin 31 is amember of the connexin family. Mutations on connexin 31 are associated with erythrokeratodermia variabilis, hearingimpairment and peripheral neuropathy. However, the pathological mechanism for connexin 31 mutants in these diseasesare still unknown. In this study, we analyzed the assembly, trafficking and metabolism of connexin 31 in HeLa cellsstably expressing connexin 31. Calcein transfer assay showed that calcein transfer was inhibited when cells weretreated with Brefeldin A or cytochalasin D, but not when treated with nocodazole or α-glycyrrhetinic acid, suggestingthat Golgi apparatus and actin filaments, but not microtubules, are crucial to the trafficking and assembly of connexin31, as well as the formation of gap junction intercellular communication by connexin 31. Additionally, α-glycyrrhetinicacid did not effectively inhibit gap junctional intercellular communication formed by connexin 31. Pulse-chase assayrevealed that connexin 31 had a half-life of about 6 h. Moreover, Western blotting and fluorescent staining demonstratedthat in HeLa cells stably expressing connexin 31, the amount of connexin 31 was significantly increased after these cellswere treated with proteasomal or lysosomal inhibitors. These findings indicate that connexin 31 was rapidly renewed,and possibly degraded by both proteasomal and lysosomal pathways.展开更多
The baculovirus P 10 protein has always represented a mystery in the field of insect virology. Like the baculovirus polyhedrin protein it is expressed at high levels very late in infection. Homologues of the Autograph...The baculovirus P 10 protein has always represented a mystery in the field of insect virology. Like the baculovirus polyhedrin protein it is expressed at high levels very late in infection. Homologues of the Autographa californica nucleopolyhedrovirus p10 gene are conserved in all Alphabaculoviruses and in other viruses of lepidopteran hosts yet is completely dispensable for virus replication and transmission. PIO is a microtubule interacting protein whose expression has been associated with the formation of a variety of complex and extensive cytoplasmic and nuclear structures. PIO has been associated with a number of roles during infection ranging from the formation of virus occlusion bodies, to affecting the rate of cellular and/or nuclear lysis during the final stages of the virus replication cycle. In this article we review recent work aimed at understanding the role of this enigmatic protein, putting them into context with recent advances in understanding of protein structure and function. We look back at a number of historical studies and observations, reanalysing their conclusions based on recent data and our own observations. The role of the P 10 protein during baculovirus replication remains elusive, however, novel avenues of investigation have been identified that will, we are sure, eventually lead to an understanding of this protein.展开更多
AIM To evaluate the role of albumin at the time of ulcerative colitis(UC) diagnosis in predicting the clinical course of disease.METHODS Nationwide cohort of patients with newly diagnosed UC in the Veterans Affairs he...AIM To evaluate the role of albumin at the time of ulcerative colitis(UC) diagnosis in predicting the clinical course of disease.METHODS Nationwide cohort of patients with newly diagnosed UC in the Veterans Affairs health care system was identified and divided into two categories: hypoalbuminemia(i.e.,≤ 3.5 gm/dl) or normal albumin levels(i.e.,> 3.5 gm/dl) at the time of UC diagnosis. The exposure of interest was presence of hypoalbuminemia defined asalbumin level ≤ 3.5 g/dl at the time of UC diagnosis. Patients were then followed over time to identify the use of ≥ 2 courses of corticosteroids(CS),thiopurines,anti-TNF medications and requirement of colectomy for UC management. RESULTS The eligible study cohort included 802 patients,but 92(11.4%) patients did not have their albumin levels checked at the time of UC diagnosis,and they were excluded. A total of 710 patients,who had albumin levels checked at time of UC diagnosis,were included in our study. Amongst them,536 patients had a normal albumin level and 174 patients had hypoalbuminemia. Patients with hypoalbuminemia at diagnosis had a higher likelihood of ≥ 2 courses of CS use(adjusted HR = 1.7,95%CI: 1.3-2.3),higher likelihood of thiopurine or anti-TNF use(adjusted HR = 1.72,95%CI: 1.23-2.40) than patients with normal albumin level at diagnosis. There was a trend of higher likelihood of colectomy in hypoalbuminemic patients,but it was not statistically significant(Adjusted HR = 1.7,95%CI: 0.90-3.25).CONCLUSION Hypoalbuminemia at disease diagnosis can serve as a prognostic marker to predict the clinical course of UC at the time of diagnosis.展开更多
AIM: To systematically investigate if cGMP/cGMP- dependent protein kinase G (PKG) signaling pathway may participate in dendroaspis natriuretic peptide (DNP)-induced relaxation of gastric circular smooth muscle. METHOD...AIM: To systematically investigate if cGMP/cGMP- dependent protein kinase G (PKG) signaling pathway may participate in dendroaspis natriuretic peptide (DNP)-induced relaxation of gastric circular smooth muscle. METHODS: The content of cGMP in guinea pig gastric antral smooth muscle tissue and perfusion solution were measured using radioimmunoassay; spontaneous contraction of gastric antral circular muscles recorded using a 4-channel physiograph; and Ca2+-activated K+ currents (IK(Ca)) and spontaneous transient outward currents (STOCs) in isolated gastric antral myocytes were recorded using the whole-cell patch clamp technique. RESULTS: DNP markedly enhanced cGMP levels in gastric antral smooth muscle tissue and in the perfusion medium. DNP induced relaxation in gastricantral circular smooth muscle, which was inhibited by KT5823, a cGMP-dependent PKG inhibitor. DNP increased IK(Ca). This effect was almost completely blocked by KT5823, and partially blocked by LY83583, an inhibitor of guanylate cyclase to change the production of cGMP. DNP also increased STOCs. The effect of DNP on STOCs was abolished in the presence of KT5823, but not affected by KT-5720, a PKA-specific inhibitor. CONCLUSION: DNP activates IK(Ca) and relaxes guinea-pig gastric antral circular smooth muscle via the cGMP/PKG-dependent singling axis instead of cAMP/ PKA pathway.展开更多
MicroRNAs (miRNA) that guide sequence-specific posttranscriptional gene silencing play an important role in gene expression required for both developmental processes and responses to environmental conditions in plan...MicroRNAs (miRNA) that guide sequence-specific posttranscriptional gene silencing play an important role in gene expression required for both developmental processes and responses to environmental conditions in plants. However, little is known about the transcriptional and posttranscriptional regulation of miRNA expression. Histone acetylation plays an important role in chromatin remodeling and is required for gene activation. By analyzing the accumulation of subset of miRNAs and the corresponding primary miRNAs in mutants of Arabidopsis, we show that histone acetyltransferase GCN5 (General control non-repressed protein 5) has a general repressive effect on miRNA production, while it is required for the expression of a subset of (e.g. stress-inducible) MIRNA genes. The general negative function of GCN5 in miRNA production is likely achieved through an indirect repression of the miRNA machinery genes such as DICER LIKE1 (DCL1), SERRATE (SE), HYPONASTIC LEAVES1 (HYL1) and ARGONAUTE1 (AGO1). Chromatin immunoprecipitation assays revealed that GCN5 targets to a subset of MIRNA genes and is required for acetylation of histone H3 lysine 14 at these loci. Moreover, inhibition of histone deacetylation by trichostatin A treatment or in histone deacetylase gene mutants impaired the accumulation of certain miRNAs. These data together suggest that Arabidopsis GCN5 interferes with the miRNA pathway at both the transcriptional and posttranscriptional levels and histone acetylation/deacetylation is an epigenetic mechanism involved in the regulation of miRNA production.展开更多
Reactive oxygen species (ROS) are molecules or ions formed by the incomplete one-electron reduction of oxygen. Ofinterest, it seems that ROS manifest dual roles, cancer promoting or cancer suppressing, in tumorigenesi...Reactive oxygen species (ROS) are molecules or ions formed by the incomplete one-electron reduction of oxygen. Ofinterest, it seems that ROS manifest dual roles, cancer promoting or cancer suppressing, in tumorigenesis. ROS participate simultaneously in two signaling pathways that have inverse functions in tumorigenesis, Ras-Raf-MEK1/2-ERK1/2 signaling and the p38 mitogen-activated protein kinases (MAPK) pathway. It is well known that Ras-Raf-MEK1/2-ERK1/2 signaling is related to oncogenesis, while the p38 MAPK pathway contributes to cancer suppression, which involves oncogene-induced senescence, inflammationinduced cellular senescence, replicative senescence, contact inhibition and DNA-damage responses. Thus, ROS may not be an absolute carcinogenic factor or cancer suppressor. The purpose of the present review is to discuss the dual roles of ROS in the pathogenesis of cancer, and the signaling pathway mediating their role in tumorigenesis.展开更多
An energy-saving light-emitting-diode(LED) street lamp was conducted. Based on the simulation by optical software TracePro,a physical street lamp system including 600 white LEDs was achieved. This system was operated ...An energy-saving light-emitting-diode(LED) street lamp was conducted. Based on the simulation by optical software TracePro,a physical street lamp system including 600 white LEDs was achieved. This system was operated under a constant current of 20 mA for each unit,and the electric power consumption of the whole lamp was only 42 W. Experimental results demonstrated that the total average illuminance reached 8.8 lx and the overall uniformity was 0.370 for a 30-m-long and 10-m-wide test area at a height of 8 m,which is fully acceptable for the current standard for sub-main road.展开更多
Simultaneous dimming controlling and data transmission are usually required in a white LED based indoor visible light communication system.However,the diming controlling of LED normally interferes the data transmissio...Simultaneous dimming controlling and data transmission are usually required in a white LED based indoor visible light communication system.However,the diming controlling of LED normally interferes the data transmission due to the modulation nonlinearity of LED.In order to solve this problem,a scheme by separating the LEDs for the functions of dimming control and data transmission respectively is proposed in this paper.In the scheme,the LEDs used for dimming control function are driven by a dc amplified circuit,and the LEDs for data transmission are driven by a digital modulation circuit respectively.In this way,the modulation distortion to the data signal caused by the modulation nonlinearity can be avoided even if the dimming is at high level dc driven current.The proof-of-concept experiment of a 2.5Mbit/s visible light communication system demonstrates that the dimming controlling and data transmission can be realized simultaneously in a simple way,and the data transmission is not affected by the dimming controlling function.Compared to previous methods,the scheme in this paper is simpler and cost effective,and makes sense when high rate data is transmitted in a visible light communication system.展开更多
The nuclear factor-kappa B (NF-κB) transcription factor plays a critical role in diverse cellular processes associated with proliferation, cell death, development, as well as innate and adaptive immune responses. ...The nuclear factor-kappa B (NF-κB) transcription factor plays a critical role in diverse cellular processes associated with proliferation, cell death, development, as well as innate and adaptive immune responses. NF-κB is normally sequestered in the cytoplasm by a family of inhibitory proteins known as inhibitors of NF-κB (IκBs). The signal pathways leading to the liberation and nuclear accumulation of NF-κB, which can be activated by a wide variety of stimuli, have been extensively studied in the past two decades. After gaining access to the nucleus, NF-κB must be actively regulated to execute its fundamental function as a transcription factor. Recent studies have highlighted the importance of nuclear signaling in the regulation of NF-κB transcriptional activity. A non-Rel subunit of NF-κB, ribosomal protein S3 (RPS3), and numerous other nuclear regulators of NF-κB, including Akirin, Nurrl, SIRT6, and others, have recently been identified, unveiling novel and exciting layers of regulatory specificity for NF-κB in the nucleus. Further insights into the nuclear events that govern NF-κB function will deepen our understanding of the elegant control of its transcriptional activity and better inform the potential rational design of therapeutics for NF-κB-associated diseases.展开更多
A method based on the wavelet transform is proposed for processing white light Interferograms from optical fiber interferometers.With this method,the envelope and the zero optical path difference(ZOPD) of white light ...A method based on the wavelet transform is proposed for processing white light Interferograms from optical fiber interferometers.With this method,the envelope and the zero optical path difference(ZOPD) of white light interferograms are obtained with high accuracy.The results agree well with those obtained by the method of center of gravity.Reasons for the insensitivity to noises of this method are discussed.The method is expected to be useful when processing white light interferograms from optical fiber interferometers,especially with low signal-to-noise ratio.展开更多
The 84-km long Changbai Mountain scenic Ring highway encircles and bisects the nature reserve. With the expected increasing traffic flow, increased wildlife vehicle collisions and barrier effects are likely. In order ...The 84-km long Changbai Mountain scenic Ring highway encircles and bisects the nature reserve. With the expected increasing traffic flow, increased wildlife vehicle collisions and barrier effects are likely. In order to identify wildlife crossing zones and future protective measurement, the authors carried out 10 wildlife highway crossing surveys during the winter in 2008-2009. For each 5-kin section, the authors recorded highway crossings of all small/mid-sized and large mammals and one large protected bird species, the hazel grouse (Bonasa bonasia) and noted snow depth and the dominant vegetation type. The authors detected 12 mammal species and one avifauna species crossing the highway 502 times. The smallest of mammal was the Eurasian red squirrel (Sciurus vulgaris). Large mammals detected included the wild boar (Sus scrofe) (64) and brown bear (Ursus arctos) (1). The average number of wildlife crossings per 5 km was 29.5. It was found that species richness and crossing frequency was higher in sections with broad leaf forest compared to sections with white birch secondary forest significantly. The authors suggested that disturbance of broad leaf forest be minimized during construction and strict protection be established for broad leaf forests around Changbai Mountain National Nature Reserve.展开更多
Objective: To investigate the expression of Tbx2 protein in pancreatic cancer tissues and its molecular regulation mechanism by Wnt/β-catenin signaling. Methods: 49 pancreatic cancer and 13 non-cancer tissue specimen...Objective: To investigate the expression of Tbx2 protein in pancreatic cancer tissues and its molecular regulation mechanism by Wnt/β-catenin signaling. Methods: 49 pancreatic cancer and 13 non-cancer tissue specimens were obtained and examined the expression of Tbx2, and the correlation between the expression of Tbx2 and clinicopathological parameters was analyzed. The immunohistochemistry, immunocytochemistry, RT-PCR and Western blot assay methods were used to detect the changes of expression levels of β-catenin and Tbx2. Results: Tbx2 was amplified in 34 of 49 pancreatic cancers, and in 13 non-cancer tissues, only one sample amplified. The further study demonstrated that Tbx2 had a significant positive correlation with tumor differentiation degree and clinical stage, but it did not relate to the sex, age and the disease region. Inhibi-tion of β-catenin degradation through the treatment of pancreatic cancer cells SW1990 with different concentrations of lithium chloride indicated that accumulation of β-catenin was sufficient to induce TBX2 expression. Conclusion: TBX2 gene plays an important role in the occurrence and development of pancreatic cancer and the accumulation of β-catenin contributes to the expression of TBX2. The Wnt/β-catenin signaling pathway participates the regulation of TBX2 in pancreatic cancer cells.展开更多
The c-Jun NH2-terminal Kinase (JNK) pathway representsone sub-group of the mitogen-activated protein (MAP)kinases which plays an important role in variousinflammatory diseases states, including inflammatorybowel disea...The c-Jun NH2-terminal Kinase (JNK) pathway representsone sub-group of the mitogen-activated protein (MAP)kinases which plays an important role in variousinflammatory diseases states, including inflammatorybowel disease (IBD). Significant progress towardsunderstanding the function of the JNK signaling pathwayhas been achieved during the past few years. Blockadeof the JNK pathway with JNK inhibitors in animal modelsof IBD lead to resolution of intestinal inflammation.Current data suggest specific JNK inhibitors hold promiseas novel therapies in IBD.展开更多
AIM: To investigate the possible mechanism by which hepatitis B virus X protein (HBx) mediates apoptosis of HepG2 cells. METHODS: HBx expression vector pcDNA3.1-X was transfected into HepG2 cells to establish an H...AIM: To investigate the possible mechanism by which hepatitis B virus X protein (HBx) mediates apoptosis of HepG2 cells. METHODS: HBx expression vector pcDNA3.1-X was transfected into HepG2 cells to establish an HBx high- expression cellular model as pcDNA3.1-X transfected group. The pcDNA3.1-X and pSilencer3.1-shHBX (HBx antagonist) were cotransfected into HepG2 cells to es- tablish an HBx low-expression model as RNAi group. Untransfected HepG2 cells and HepG2 cells transfected with negative control plasmid were used as controls. Apoptosis rate, the expression of Fas/FasL signaling pathway-related proteins and the phosphorylation lev- els of MLK3, MKK7 and JNKs, which are upstream molecules of death receptor pathways and belong to the family of mitogen-activated protein kinases (MAPKs),were measured in each group RESULTS: Compared with HepG2 cell group and RNAi group, apoptosis rate, the expression of Fas and FasL proteins, and the activation of MLK3, MKK7 and 3NKs were increased in the pcDNA3.1-X transfected group. The activation of JNKs and expression of FasL protein were inhibited in the pcDNA3.1-X transfected group when treated with a known JNK inhibitor, SP600125. When authors treated pcDNA3.1-X transfected group with K252a, a known MLK3 inhibitor, the activation of MLK3, MKK7 and 3NKs as well as expression of FasL protein was inhibited. Furthermore, cell apoptosis rate was also significantly declined in the presence of K252a in the pcDNA3.1-X transfected group. CONCLUSION: HBx can induce HepG2 cell apoptosis via a novel active MLK3-MKK7-JNKs signaling module to upregulate FasL protein expression.展开更多
文摘Objective To investigate the effect of mucin 1(MUC1)on the proliferation and apoptosis of nasopharyngeal carcinoma(NPC)and its regulatory mechanism.Methods The 60 NPC and paired para-cancer normal tissues were collected from October 2020 to July 2021 in Quanzhou First Hospital.The expression of MUC1 was measured by real-time quantitative PCR(qPCR)in the patients with PNC.The 5-8F and HNE1 cells were transfected with siRNA control(si-control)or siRNA targeting MUC1(si-MUC1).Cell proliferation was analyzed by cell counting kit-8 and colony formation assay,and apoptosis was analyzed by flow cytometry analysis in the 5-8F and HNE1 cells.The qPCR and ELISA were executed to analyze the levels of TNF-αand IL-6.Western blot was performed to measure the expression of MUC1,NFкB and apoptosis-related proteins(Bax and Bcl-2).Results The expression of MUC1 was up-regulated in the NPC tissues,and NPC patients with the high MUC1 expression were inclined to EBV infection,growth and metastasis of NPC.Loss of MUC1 restrained malignant features,including the proliferation and apoptosis,downregulated the expression of p-IкB、p-P65 and Bcl-2 and upregulated the expression of Bax in the NPC cells.Conclusion Downregulation of MUC1 restrained biological characteristics of malignancy,including cell proliferation and apoptosis,by inactivating NF-κB signaling pathway in NPC.
基金This work was supported by grants from Three Founda-tions of Hunan Province (00JZY2155) and International Cooperation Project
文摘S-RNase-mediated gametophytic self-incompatibility (GSI) is controlled by a multiallelic S-locus at which two separate genes, the female (pistil) and male (pollen) specificity determinants, are tightly linked. This review described both the identification of pollen specific F-box genes, SLF/SFBs, in Antirrhinum, Petunia and Prunus species and the demonstration of SLF/SFB as pollen determinant together with their functions in GSI response. Recent studies of how the pollen determinant functions in pollination reaction revealed that pollen determinant interacted with S-RNases in a non-allele-specific manner. It targeted all of the non-self S-RNases for ubiquitination through a functional SCF complex and subsequent degradation via 26S proteasome pathway in compatible reaction. It allows pollen tube to reach into the embryo sac and to finish double fertilization. In incompatible response, the intact self S-RNases were left to function as a cytotoxin that degrades self-pollen tube RNA, resulting in the cessation of pollen tube growth.
基金This work was supported in part by grants from National Natural Science Foundation of China(No.30328004,No.30571269)National Institutes of Health(R01 GM66258-01).
文摘Steroids function as signaling molecules in both animals and plants. While animal steroid hormones are perceived by nuclear receptor family of transcription factors, brassinosteroids (BR) in plants are perceived by a cell surface receptor kinase, BRI 1. Recent studies have demonstrated that BR binding to the extracellular domain of BRI 1 induces kinase activation and dimerization with another receptor kinase, BAKI. Activated BRI 1 or BAKI then regulate, possibly indirectly, the activities of BIN2 kinase and/or BSU 1 phosphatase, which directly regulate the phosphorylation status and nuclear accumulation of two homologous transcription factors, BZRI and BES 1. BZRI and BES 1 directly bind to promoters of BR responsive genes to regulate their expression. The BR signaling pathway has become a paradigm for both receptor kinase signaling in plants and steroid signaling by cell surface receptors in general.
基金supported by "the National High Tech-nology Research and Development Program of China, No.2002BA711A07-03, 08the Major State Basic ResearchDevelopment Program of China, No. 2001CB510302 and2004CB518800the National Natural Science Foun-dation of China, No. 30370737.
文摘Gap junctions, consisting of connexins, allow the exchange of small molecules (<1 kD) between adjacent cells, thusproviding a mechanism for synchronizing the responses of groups of cells to environmental stimuli. Connexin 31 is amember of the connexin family. Mutations on connexin 31 are associated with erythrokeratodermia variabilis, hearingimpairment and peripheral neuropathy. However, the pathological mechanism for connexin 31 mutants in these diseasesare still unknown. In this study, we analyzed the assembly, trafficking and metabolism of connexin 31 in HeLa cellsstably expressing connexin 31. Calcein transfer assay showed that calcein transfer was inhibited when cells weretreated with Brefeldin A or cytochalasin D, but not when treated with nocodazole or α-glycyrrhetinic acid, suggestingthat Golgi apparatus and actin filaments, but not microtubules, are crucial to the trafficking and assembly of connexin31, as well as the formation of gap junction intercellular communication by connexin 31. Additionally, α-glycyrrhetinicacid did not effectively inhibit gap junctional intercellular communication formed by connexin 31. Pulse-chase assayrevealed that connexin 31 had a half-life of about 6 h. Moreover, Western blotting and fluorescent staining demonstratedthat in HeLa cells stably expressing connexin 31, the amount of connexin 31 was significantly increased after these cellswere treated with proteasomal or lysosomal inhibitors. These findings indicate that connexin 31 was rapidly renewed,and possibly degraded by both proteasomal and lysosomal pathways.
文摘The baculovirus P 10 protein has always represented a mystery in the field of insect virology. Like the baculovirus polyhedrin protein it is expressed at high levels very late in infection. Homologues of the Autographa californica nucleopolyhedrovirus p10 gene are conserved in all Alphabaculoviruses and in other viruses of lepidopteran hosts yet is completely dispensable for virus replication and transmission. PIO is a microtubule interacting protein whose expression has been associated with the formation of a variety of complex and extensive cytoplasmic and nuclear structures. PIO has been associated with a number of roles during infection ranging from the formation of virus occlusion bodies, to affecting the rate of cellular and/or nuclear lysis during the final stages of the virus replication cycle. In this article we review recent work aimed at understanding the role of this enigmatic protein, putting them into context with recent advances in understanding of protein structure and function. We look back at a number of historical studies and observations, reanalysing their conclusions based on recent data and our own observations. The role of the P 10 protein during baculovirus replication remains elusive, however, novel avenues of investigation have been identified that will, we are sure, eventually lead to an understanding of this protein.
文摘AIM To evaluate the role of albumin at the time of ulcerative colitis(UC) diagnosis in predicting the clinical course of disease.METHODS Nationwide cohort of patients with newly diagnosed UC in the Veterans Affairs health care system was identified and divided into two categories: hypoalbuminemia(i.e.,≤ 3.5 gm/dl) or normal albumin levels(i.e.,> 3.5 gm/dl) at the time of UC diagnosis. The exposure of interest was presence of hypoalbuminemia defined asalbumin level ≤ 3.5 g/dl at the time of UC diagnosis. Patients were then followed over time to identify the use of ≥ 2 courses of corticosteroids(CS),thiopurines,anti-TNF medications and requirement of colectomy for UC management. RESULTS The eligible study cohort included 802 patients,but 92(11.4%) patients did not have their albumin levels checked at the time of UC diagnosis,and they were excluded. A total of 710 patients,who had albumin levels checked at time of UC diagnosis,were included in our study. Amongst them,536 patients had a normal albumin level and 174 patients had hypoalbuminemia. Patients with hypoalbuminemia at diagnosis had a higher likelihood of ≥ 2 courses of CS use(adjusted HR = 1.7,95%CI: 1.3-2.3),higher likelihood of thiopurine or anti-TNF use(adjusted HR = 1.72,95%CI: 1.23-2.40) than patients with normal albumin level at diagnosis. There was a trend of higher likelihood of colectomy in hypoalbuminemic patients,but it was not statistically significant(Adjusted HR = 1.7,95%CI: 0.90-3.25).CONCLUSION Hypoalbuminemia at disease diagnosis can serve as a prognostic marker to predict the clinical course of UC at the time of diagnosis.
基金The National Natural Science Foundation of China, No. 30800382the Youth Science Foundation of Dalian to Professor Hui-Shu Guo, No. 2006B3NS218
文摘AIM: To systematically investigate if cGMP/cGMP- dependent protein kinase G (PKG) signaling pathway may participate in dendroaspis natriuretic peptide (DNP)-induced relaxation of gastric circular smooth muscle. METHODS: The content of cGMP in guinea pig gastric antral smooth muscle tissue and perfusion solution were measured using radioimmunoassay; spontaneous contraction of gastric antral circular muscles recorded using a 4-channel physiograph; and Ca2+-activated K+ currents (IK(Ca)) and spontaneous transient outward currents (STOCs) in isolated gastric antral myocytes were recorded using the whole-cell patch clamp technique. RESULTS: DNP markedly enhanced cGMP levels in gastric antral smooth muscle tissue and in the perfusion medium. DNP induced relaxation in gastricantral circular smooth muscle, which was inhibited by KT5823, a cGMP-dependent PKG inhibitor. DNP increased IK(Ca). This effect was almost completely blocked by KT5823, and partially blocked by LY83583, an inhibitor of guanylate cyclase to change the production of cGMP. DNP also increased STOCs. The effect of DNP on STOCs was abolished in the presence of KT5823, but not affected by KT-5720, a PKA-specific inhibitor. CONCLUSION: DNP activates IK(Ca) and relaxes guinea-pig gastric antral circular smooth muscle via the cGMP/PKG-dependent singling axis instead of cAMP/ PKA pathway.
文摘MicroRNAs (miRNA) that guide sequence-specific posttranscriptional gene silencing play an important role in gene expression required for both developmental processes and responses to environmental conditions in plants. However, little is known about the transcriptional and posttranscriptional regulation of miRNA expression. Histone acetylation plays an important role in chromatin remodeling and is required for gene activation. By analyzing the accumulation of subset of miRNAs and the corresponding primary miRNAs in mutants of Arabidopsis, we show that histone acetyltransferase GCN5 (General control non-repressed protein 5) has a general repressive effect on miRNA production, while it is required for the expression of a subset of (e.g. stress-inducible) MIRNA genes. The general negative function of GCN5 in miRNA production is likely achieved through an indirect repression of the miRNA machinery genes such as DICER LIKE1 (DCL1), SERRATE (SE), HYPONASTIC LEAVES1 (HYL1) and ARGONAUTE1 (AGO1). Chromatin immunoprecipitation assays revealed that GCN5 targets to a subset of MIRNA genes and is required for acetylation of histone H3 lysine 14 at these loci. Moreover, inhibition of histone deacetylation by trichostatin A treatment or in histone deacetylase gene mutants impaired the accumulation of certain miRNAs. These data together suggest that Arabidopsis GCN5 interferes with the miRNA pathway at both the transcriptional and posttranscriptional levels and histone acetylation/deacetylation is an epigenetic mechanism involved in the regulation of miRNA production.
基金Supported by National Natural Science Foundation of China, No. 30750013 Key Science Research Project Natural Science Foundation of Xiamen, No. WKZ0501
文摘Reactive oxygen species (ROS) are molecules or ions formed by the incomplete one-electron reduction of oxygen. Ofinterest, it seems that ROS manifest dual roles, cancer promoting or cancer suppressing, in tumorigenesis. ROS participate simultaneously in two signaling pathways that have inverse functions in tumorigenesis, Ras-Raf-MEK1/2-ERK1/2 signaling and the p38 mitogen-activated protein kinases (MAPK) pathway. It is well known that Ras-Raf-MEK1/2-ERK1/2 signaling is related to oncogenesis, while the p38 MAPK pathway contributes to cancer suppression, which involves oncogene-induced senescence, inflammationinduced cellular senescence, replicative senescence, contact inhibition and DNA-damage responses. Thus, ROS may not be an absolute carcinogenic factor or cancer suppressor. The purpose of the present review is to discuss the dual roles of ROS in the pathogenesis of cancer, and the signaling pathway mediating their role in tumorigenesis.
文摘An energy-saving light-emitting-diode(LED) street lamp was conducted. Based on the simulation by optical software TracePro,a physical street lamp system including 600 white LEDs was achieved. This system was operated under a constant current of 20 mA for each unit,and the electric power consumption of the whole lamp was only 42 W. Experimental results demonstrated that the total average illuminance reached 8.8 lx and the overall uniformity was 0.370 for a 30-m-long and 10-m-wide test area at a height of 8 m,which is fully acceptable for the current standard for sub-main road.
基金financially supported by National Natural Science Foundation of China(No.61475094)National 973 Program of China(No.2013CB329202)
文摘Simultaneous dimming controlling and data transmission are usually required in a white LED based indoor visible light communication system.However,the diming controlling of LED normally interferes the data transmission due to the modulation nonlinearity of LED.In order to solve this problem,a scheme by separating the LEDs for the functions of dimming control and data transmission respectively is proposed in this paper.In the scheme,the LEDs used for dimming control function are driven by a dc amplified circuit,and the LEDs for data transmission are driven by a digital modulation circuit respectively.In this way,the modulation distortion to the data signal caused by the modulation nonlinearity can be avoided even if the dimming is at high level dc driven current.The proof-of-concept experiment of a 2.5Mbit/s visible light communication system demonstrates that the dimming controlling and data transmission can be realized simultaneously in a simple way,and the data transmission is not affected by the dimming controlling function.Compared to previous methods,the scheme in this paper is simpler and cost effective,and makes sense when high rate data is transmitted in a visible light communication system.
文摘The nuclear factor-kappa B (NF-κB) transcription factor plays a critical role in diverse cellular processes associated with proliferation, cell death, development, as well as innate and adaptive immune responses. NF-κB is normally sequestered in the cytoplasm by a family of inhibitory proteins known as inhibitors of NF-κB (IκBs). The signal pathways leading to the liberation and nuclear accumulation of NF-κB, which can be activated by a wide variety of stimuli, have been extensively studied in the past two decades. After gaining access to the nucleus, NF-κB must be actively regulated to execute its fundamental function as a transcription factor. Recent studies have highlighted the importance of nuclear signaling in the regulation of NF-κB transcriptional activity. A non-Rel subunit of NF-κB, ribosomal protein S3 (RPS3), and numerous other nuclear regulators of NF-κB, including Akirin, Nurrl, SIRT6, and others, have recently been identified, unveiling novel and exciting layers of regulatory specificity for NF-κB in the nucleus. Further insights into the nuclear events that govern NF-κB function will deepen our understanding of the elegant control of its transcriptional activity and better inform the potential rational design of therapeutics for NF-κB-associated diseases.
文摘A method based on the wavelet transform is proposed for processing white light Interferograms from optical fiber interferometers.With this method,the envelope and the zero optical path difference(ZOPD) of white light interferograms are obtained with high accuracy.The results agree well with those obtained by the method of center of gravity.Reasons for the insensitivity to noises of this method are discussed.The method is expected to be useful when processing white light interferograms from optical fiber interferometers,especially with low signal-to-noise ratio.
文摘The 84-km long Changbai Mountain scenic Ring highway encircles and bisects the nature reserve. With the expected increasing traffic flow, increased wildlife vehicle collisions and barrier effects are likely. In order to identify wildlife crossing zones and future protective measurement, the authors carried out 10 wildlife highway crossing surveys during the winter in 2008-2009. For each 5-kin section, the authors recorded highway crossings of all small/mid-sized and large mammals and one large protected bird species, the hazel grouse (Bonasa bonasia) and noted snow depth and the dominant vegetation type. The authors detected 12 mammal species and one avifauna species crossing the highway 502 times. The smallest of mammal was the Eurasian red squirrel (Sciurus vulgaris). Large mammals detected included the wild boar (Sus scrofe) (64) and brown bear (Ursus arctos) (1). The average number of wildlife crossings per 5 km was 29.5. It was found that species richness and crossing frequency was higher in sections with broad leaf forest compared to sections with white birch secondary forest significantly. The authors suggested that disturbance of broad leaf forest be minimized during construction and strict protection be established for broad leaf forests around Changbai Mountain National Nature Reserve.
文摘Objective: To investigate the expression of Tbx2 protein in pancreatic cancer tissues and its molecular regulation mechanism by Wnt/β-catenin signaling. Methods: 49 pancreatic cancer and 13 non-cancer tissue specimens were obtained and examined the expression of Tbx2, and the correlation between the expression of Tbx2 and clinicopathological parameters was analyzed. The immunohistochemistry, immunocytochemistry, RT-PCR and Western blot assay methods were used to detect the changes of expression levels of β-catenin and Tbx2. Results: Tbx2 was amplified in 34 of 49 pancreatic cancers, and in 13 non-cancer tissues, only one sample amplified. The further study demonstrated that Tbx2 had a significant positive correlation with tumor differentiation degree and clinical stage, but it did not relate to the sex, age and the disease region. Inhibi-tion of β-catenin degradation through the treatment of pancreatic cancer cells SW1990 with different concentrations of lithium chloride indicated that accumulation of β-catenin was sufficient to induce TBX2 expression. Conclusion: TBX2 gene plays an important role in the occurrence and development of pancreatic cancer and the accumulation of β-catenin contributes to the expression of TBX2. The Wnt/β-catenin signaling pathway participates the regulation of TBX2 in pancreatic cancer cells.
文摘The c-Jun NH2-terminal Kinase (JNK) pathway representsone sub-group of the mitogen-activated protein (MAP)kinases which plays an important role in variousinflammatory diseases states, including inflammatorybowel disease (IBD). Significant progress towardsunderstanding the function of the JNK signaling pathwayhas been achieved during the past few years. Blockadeof the JNK pathway with JNK inhibitors in animal modelsof IBD lead to resolution of intestinal inflammation.Current data suggest specific JNK inhibitors hold promiseas novel therapies in IBD.
基金Supported by Natural Science Foundation of Jiangsu Province,No.10KJD310002The Graduate Innovation Program in Science and Technology of Xuzhou Medical College,No.XYCX201005
文摘AIM: To investigate the possible mechanism by which hepatitis B virus X protein (HBx) mediates apoptosis of HepG2 cells. METHODS: HBx expression vector pcDNA3.1-X was transfected into HepG2 cells to establish an HBx high- expression cellular model as pcDNA3.1-X transfected group. The pcDNA3.1-X and pSilencer3.1-shHBX (HBx antagonist) were cotransfected into HepG2 cells to es- tablish an HBx low-expression model as RNAi group. Untransfected HepG2 cells and HepG2 cells transfected with negative control plasmid were used as controls. Apoptosis rate, the expression of Fas/FasL signaling pathway-related proteins and the phosphorylation lev- els of MLK3, MKK7 and JNKs, which are upstream molecules of death receptor pathways and belong to the family of mitogen-activated protein kinases (MAPKs),were measured in each group RESULTS: Compared with HepG2 cell group and RNAi group, apoptosis rate, the expression of Fas and FasL proteins, and the activation of MLK3, MKK7 and 3NKs were increased in the pcDNA3.1-X transfected group. The activation of JNKs and expression of FasL protein were inhibited in the pcDNA3.1-X transfected group when treated with a known JNK inhibitor, SP600125. When authors treated pcDNA3.1-X transfected group with K252a, a known MLK3 inhibitor, the activation of MLK3, MKK7 and 3NKs as well as expression of FasL protein was inhibited. Furthermore, cell apoptosis rate was also significantly declined in the presence of K252a in the pcDNA3.1-X transfected group. CONCLUSION: HBx can induce HepG2 cell apoptosis via a novel active MLK3-MKK7-JNKs signaling module to upregulate FasL protein expression.