The host takes use of pattern recognition receptors （PRRs） to defend against pathogen invasion or cellular damage. Among microorganism-associated molecular patterns detected by host PRRs, nucleic acids derived from ...The host takes use of pattern recognition receptors （PRRs） to defend against pathogen invasion or cellular damage. Among microorganism-associated molecular patterns detected by host PRRs, nucleic acids derived from bacteria or viruses are tightly supervised, providing a fundamental mechanism of host defense. Pathogenic DNAs are supposed to be detected by DNA sensors that induce the activation of NFKB or TBKI-IRF3 pathway. DNA sensor cGAS is widely expressed in innate immune cells and is a key sensor of invading DNAs in several cell types, cGAS binds to DNA, followed by a conformational change that allows the synthesis of cyclic guanosine monophosphate-adenosine monophosphate （cGAMP） from adenosine triphosphate and guanosine triphos- phate, cGAMP is a strong activator of STING that can activate IRF3 and subsequent type I interferon produc- tion. Here we describe recent progresses in DNA sensors especially cGAS in the innate immune responses against pathogenic DNAs.展开更多
Third generation DNA sequencing relies on monitoring the ionic current blockage during the DNA molecule’s threading through a nanoscale pore.It is still really tough to attain the single base discrimination on a DNA ...Third generation DNA sequencing relies on monitoring the ionic current blockage during the DNA molecule’s threading through a nanoscale pore.It is still really tough to attain the single base discrimination on a DNA strand by merely analyzing the ionic current due to speedy DNA translocation and low spatial resolution.More integrated configurations are pursued to present versatile comparative dissimilarities of the four bases by enhancing the spatial resolution within a DNA molecule translocation event,such as transverse tunneling current,local potential change,and capacitance oriented voltage resonance.In this mini review,the insight is provided into the status quo on several functionalized techniques and methodologies for DNA sequencing and furthermore concluding remark and outlook are presented.展开更多
Microbial activity is the cause of a variety of problems in water injection systems, e.g., microbial corrosion, plugging, and biofouling. Efficient monitoring of Saudi Aramco’s vast water injection system requires th...Microbial activity is the cause of a variety of problems in water injection systems, e.g., microbial corrosion, plugging, and biofouling. Efficient monitoring of Saudi Aramco’s vast water injection system requires the development of online and automated technologies for monitoring microbial activities in the system. A previous system review and technology screening has identified five single-analyte strategies [1], which were evaluated in this study with a laboratory-scale setup to determine their applicability for automated determination of microbial activity in the injection water system. Four of the five single-analyte measuring principles tested in the laboratory setup were deemed less suitable for automation and/or reliable for use in the detection of microbial activity in the company injection water system. These four principles were: luminescence assay for adenosine-5’-triphosphate (ATP), detection and electrochemical measurements of H<sub>2</sub>S, determination of pH by electrochemical sensor, and measurement of oxidation-reduction potential (ORP). The strategy of staining cells with fluorescent DNA dyes, followed by quantification of fluorescence signals, was identified to hold, with proper optimization of DNA staining and fluorescence detection, a very promising potential for integration in automated, online sensors for microbial activity in the injection water system.展开更多
Before a pathogen even enters a cell, intrinsic immune defenses are active. This first-line defense is mediated by a variety of constitutively expressed cell proteins collectively termed "restriction factors"...Before a pathogen even enters a cell, intrinsic immune defenses are active. This first-line defense is mediated by a variety of constitutively expressed cell proteins collectively termed "restriction factors"(RFs), and they form a vital element of the immune response to virus infections. Over time, however, viruses have evolved in a variety ways so that they are able to overcome these RF defenses via mechanisms that are specific for each virus. This review provides a summary of the universal characteristics of RFs, and goes on to focus on the strategies employed by some of the most important RFs in their attempt to control human cytomegalovirus(HCMV) infection. This is followed by a discussion of the counter-restriction mechanisms evolved by viruses to circumvent the host cell's intrinsic immune defenses. RFs include nuclear proteins IFN-γ inducible protein 16(IFI16)(a Pyrin/HIN domain protein), Sp100, promyelocytic leukemia, and h Daxx; the latter three being the keys elements of nuclear domain 10(ND10). IFI16 inhibits the synthesis of virus DNA by downregulating UL54 transcription- a gene encoding a CMV DNA polymerase; in response, the virus antagonizes IFI16 via a process involving viral proteins UL97 and pp65(p UL83), which results in the mislocalizing of IFI16 into the cytoplasm. In contrast, viral regulatory proteins, including pp71 and IE1, seek to modify or disrupt the ND10 proteins and thus block or reverse their inhibitory effects upon virus replication. All in all, detailed knowledge of these HCMV counter-restriction mechanisms will be fundamental for the future development of new strategies for combating HCMV infection and for identifying novel therapeutic agents.展开更多
This paper demonstrates electrical detection of single strand deoxyribonucleic acid (ssDNA) conjugation by AlGaN/GaN hetero-structure field effect transistor (HFET) biological sensors. The probe ssDNA molecules are mo...This paper demonstrates electrical detection of single strand deoxyribonucleic acid (ssDNA) conjugation by AlGaN/GaN hetero-structure field effect transistor (HFET) biological sensors. The probe ssDNA molecules are modified by thiol groups. The immobilization of probe molecules is achieved by S-Au bonding on a thin layer of gold film in the sensing area. The immobilization and hybridization process are firstly implemented on Si surfaces and checked by fluorescent and atomic force microscopy (AFM) imaging. The hybridization process is monitored on AlGaN/GaN HFETs. Time-dependent current change is observed when a matched ssDNA solution is applied, while no response is observed for a mismatched ssDNA sequence. The DNA hybridization process is dominated by the conjugation between matched ssDNA sequences in the first few tens of seconds. After that, the hybridization process is dominated by mass transfer processes and saturation of the immobilized probe ssDNA molecules.展开更多
The mutation detections of KRAS and BRAF genes are of significant importance to predict the responses to anti-cancer therapy and develop new drugs. In this paper, we developed a multi-step fluorescence resonance energ...The mutation detections of KRAS and BRAF genes are of significant importance to predict the responses to anti-cancer therapy and develop new drugs. In this paper, we developed a multi-step fluorescence resonance energy transfer (FRET) assay for multiplex detection of KRAS and BRAF mutations using cationic conjugated polymers (CCP). The newly established detection system could detect as low as 2% mutant DNAs in DNA admixtures. By triggering the emission intensity change of CCP and the dyes labeled in the DNA, four possible statuses (three mutations and one wildtype) can be differentiated in one extension reaction. The detection efficiency of this new method in clinical molecular diagnosis was validated by determining KRAS and BRAF mutations of 51 formalin-fixed paraffin-embedded (FFPE) ovary tissue samples. Furthermore, the result of the CCP-based multi-step FRET assay can be directly visualized under UV light so that no expensive instruments and technical expertise are needed. Thus, the assay provides a sensitive, reliable, cost-effective and simple method for the detection of disease-related gene mutations.展开更多
文摘The host takes use of pattern recognition receptors （PRRs） to defend against pathogen invasion or cellular damage. Among microorganism-associated molecular patterns detected by host PRRs, nucleic acids derived from bacteria or viruses are tightly supervised, providing a fundamental mechanism of host defense. Pathogenic DNAs are supposed to be detected by DNA sensors that induce the activation of NFKB or TBKI-IRF3 pathway. DNA sensor cGAS is widely expressed in innate immune cells and is a key sensor of invading DNAs in several cell types, cGAS binds to DNA, followed by a conformational change that allows the synthesis of cyclic guanosine monophosphate-adenosine monophosphate （cGAMP） from adenosine triphosphate and guanosine triphos- phate, cGAMP is a strong activator of STING that can activate IRF3 and subsequent type I interferon produc- tion. Here we describe recent progresses in DNA sensors especially cGAS in the innate immune responses against pathogenic DNAs.
基金supported by the National Basic Research Program of China(Grant No.2011CB707605)National Natural Science Foundation of China(Grant Nos.50925519 and 51375092)G.S.Wu was supported by the Scientific Research Foundation of Graduate School of Southeast University
文摘Third generation DNA sequencing relies on monitoring the ionic current blockage during the DNA molecule’s threading through a nanoscale pore.It is still really tough to attain the single base discrimination on a DNA strand by merely analyzing the ionic current due to speedy DNA translocation and low spatial resolution.More integrated configurations are pursued to present versatile comparative dissimilarities of the four bases by enhancing the spatial resolution within a DNA molecule translocation event,such as transverse tunneling current,local potential change,and capacitance oriented voltage resonance.In this mini review,the insight is provided into the status quo on several functionalized techniques and methodologies for DNA sequencing and furthermore concluding remark and outlook are presented.
文摘Microbial activity is the cause of a variety of problems in water injection systems, e.g., microbial corrosion, plugging, and biofouling. Efficient monitoring of Saudi Aramco’s vast water injection system requires the development of online and automated technologies for monitoring microbial activities in the system. A previous system review and technology screening has identified five single-analyte strategies [1], which were evaluated in this study with a laboratory-scale setup to determine their applicability for automated determination of microbial activity in the injection water system. Four of the five single-analyte measuring principles tested in the laboratory setup were deemed less suitable for automation and/or reliable for use in the detection of microbial activity in the company injection water system. These four principles were: luminescence assay for adenosine-5’-triphosphate (ATP), detection and electrochemical measurements of H<sub>2</sub>S, determination of pH by electrochemical sensor, and measurement of oxidation-reduction potential (ORP). The strategy of staining cells with fluorescent DNA dyes, followed by quantification of fluorescence signals, was identified to hold, with proper optimization of DNA staining and fluorescence detection, a very promising potential for integration in automated, online sensors for microbial activity in the injection water system.
基金Supported by Italian Ministry of Education,University and Research--MIUR(PRIN 2012)to S.Landolfo(2012SNMJRL)and V.Dell’Oste(20127MFYBR)University of Turin,Research Funding 2014 to S.Landolfo,M.De Andrea,and V.Dell’OsteRegione Piemonte to S.Landolfo(PAR-FCS 2007/2013)
文摘Before a pathogen even enters a cell, intrinsic immune defenses are active. This first-line defense is mediated by a variety of constitutively expressed cell proteins collectively termed "restriction factors"(RFs), and they form a vital element of the immune response to virus infections. Over time, however, viruses have evolved in a variety ways so that they are able to overcome these RF defenses via mechanisms that are specific for each virus. This review provides a summary of the universal characteristics of RFs, and goes on to focus on the strategies employed by some of the most important RFs in their attempt to control human cytomegalovirus(HCMV) infection. This is followed by a discussion of the counter-restriction mechanisms evolved by viruses to circumvent the host cell's intrinsic immune defenses. RFs include nuclear proteins IFN-γ inducible protein 16(IFI16)(a Pyrin/HIN domain protein), Sp100, promyelocytic leukemia, and h Daxx; the latter three being the keys elements of nuclear domain 10(ND10). IFI16 inhibits the synthesis of virus DNA by downregulating UL54 transcription- a gene encoding a CMV DNA polymerase; in response, the virus antagonizes IFI16 via a process involving viral proteins UL97 and pp65(p UL83), which results in the mislocalizing of IFI16 into the cytoplasm. In contrast, viral regulatory proteins, including pp71 and IE1, seek to modify or disrupt the ND10 proteins and thus block or reverse their inhibitory effects upon virus replication. All in all, detailed knowledge of these HCMV counter-restriction mechanisms will be fundamental for the future development of new strategies for combating HCMV infection and for identifying novel therapeutic agents.
基金supported by National Science Foundation of USA(ECCS-0824170, CMMI-0928888, EEC-0914790)World Class University Program funded by the Ministry of Education, Science and Technology through the National Research Foundation of Korea (R31-10026)
文摘This paper demonstrates electrical detection of single strand deoxyribonucleic acid (ssDNA) conjugation by AlGaN/GaN hetero-structure field effect transistor (HFET) biological sensors. The probe ssDNA molecules are modified by thiol groups. The immobilization of probe molecules is achieved by S-Au bonding on a thin layer of gold film in the sensing area. The immobilization and hybridization process are firstly implemented on Si surfaces and checked by fluorescent and atomic force microscopy (AFM) imaging. The hybridization process is monitored on AlGaN/GaN HFETs. Time-dependent current change is observed when a matched ssDNA solution is applied, while no response is observed for a mismatched ssDNA sequence. The DNA hybridization process is dominated by the conjugation between matched ssDNA sequences in the first few tens of seconds. After that, the hybridization process is dominated by mass transfer processes and saturation of the immobilized probe ssDNA molecules.
基金supported by the National Natural Science Foundation of China (90913014, 21021091)
文摘The mutation detections of KRAS and BRAF genes are of significant importance to predict the responses to anti-cancer therapy and develop new drugs. In this paper, we developed a multi-step fluorescence resonance energy transfer (FRET) assay for multiplex detection of KRAS and BRAF mutations using cationic conjugated polymers (CCP). The newly established detection system could detect as low as 2% mutant DNAs in DNA admixtures. By triggering the emission intensity change of CCP and the dyes labeled in the DNA, four possible statuses (three mutations and one wildtype) can be differentiated in one extension reaction. The detection efficiency of this new method in clinical molecular diagnosis was validated by determining KRAS and BRAF mutations of 51 formalin-fixed paraffin-embedded (FFPE) ovary tissue samples. Furthermore, the result of the CCP-based multi-step FRET assay can be directly visualized under UV light so that no expensive instruments and technical expertise are needed. Thus, the assay provides a sensitive, reliable, cost-effective and simple method for the detection of disease-related gene mutations.
