Since transgene silencing was found in transgenic plants,many scholars have studied it extensively and considered that it has three functional mechanisms:post dependent gene silencing,transcriptional gene silencing,p...Since transgene silencing was found in transgenic plants,many scholars have studied it extensively and considered that it has three functional mechanisms:post dependent gene silencing,transcriptional gene silencing,post transcriptional gene silencing.At the moment,people have mainly focused on the study of post transcriptional gene silencing and found its features:extensivity,conduction and peculiarity,also put forward some hypothesis for its mechanisms,for example,RNA threshold model,aberrant RNA model,inter or intra molecular base pairing model and so on.Furthermore,post transcriptional gene silencing is being applied in gene engineering of plants.Recently the people have found that post transcriptional gene silencing has bearing on capacity plants resisting virus.Many researchers have studied post transcriptional gene silencing,but there are some questions which need be solved in the future.This article summarizes progresses in features,mechanisms,applies of post transcriptional gene silencing about transgenic plants.展开更多
miRNAs are a class of small, ∽22nt, non-coding RNAs that negatively regulate gene expression at the posttranscriptional level. They play profound and pervasive roles in manipulating gene expression involved in cell d...miRNAs are a class of small, ∽22nt, non-coding RNAs that negatively regulate gene expression at the posttranscriptional level. They play profound and pervasive roles in manipulating gene expression involved in cell development, proliferation and apoptosis in various eukaryotes, which, in theory, could provide an access to many human diseases in theory. Recent evidence demonstrates that aberrant miRNA expression is a hallmark of tumor development, revealing that miRNA genes could function as potential oncogenes and repressors in the human body. miRNAs can affect tumorigenesis mainly by interrupting the cell cycle at the cellular level and by interacting with signaling, oncogenes and with the response to environmental factors at the molecular level. The established miRNA expression signature could be a potent tool to diagnose and treat human cancers in the future.展开更多
Hepatitis C virus （HCV） needs to tightly manipulate host defences in order to establish infection. The innate immune response slows down viral replication by activating cytokines such as the type Ⅰ interferons （I...Hepatitis C virus （HCV） needs to tightly manipulate host defences in order to establish infection. The innate immune response slows down viral replication by activating cytokines such as the type Ⅰ interferons （IFN-α/ β）, which trigger the synthesis of antiviral proteins and modulate the adaptive immune system. HCV has therefore developed a number of countermeasures to stay ahead of the IFN system. Here, I will attempt to summarize the current state of research regarding IFN responses against HCV and the viral escape strategies. Particular emphasis will be put on the newly discovered mechanisms HCV employs to avoid the induction of IFN in infected cells.展开更多
In this study, we compared the transcriptomes of Nannochloropsis oceanica cultured in f/2 medium prepared with seawater and freshwater, respectively, aiming to understand the acclimation mechanism of this alga to fres...In this study, we compared the transcriptomes of Nannochloropsis oceanica cultured in f/2 medium prepared with seawater and freshwater, respectively, aiming to understand the acclimation mechanism of this alga to freshwater. Differentially expressed genes were mainly assigned to the degradation of cell components, ion transportation, and ribosomal biogenesis. These find- ings indicate that the algal cells degrade its components （mainly amino acids and fatty acids） to yield excessive energy （ATP） to maintain cellular ion （mainly K＋ and Ca〉） homeostasis, while the depletion of amino acids and ATP, and the reduction of ribosomes attenuate the protein translation and finally slow down the cell growth.展开更多
The nuclear receptor PPARs are fundamentally important for energy homeostasis. Through their distinct yet overlapping functions and tissue distribution, the PPARs regulate many aspects of energy metabolism at the tran...The nuclear receptor PPARs are fundamentally important for energy homeostasis. Through their distinct yet overlapping functions and tissue distribution, the PPARs regulate many aspects of energy metabolism at the transcriptional level. Functional impairment or dysregulation of these receptors leads to a variety of metabolic diseases, while their ligands offer many metabolic benefits. Studies of these receptors have advanced our knowledge of the transcriptional basis of energy metabolism and helped us understand the pathogenic mechanisms of metabolic syndrome.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
Viral load measurements are an essential tool for the long-term clinical care of human immunodeficiency virus （HIV）-positive individuals. The gold standards in viral load instrumentation, however, are still too limi...Viral load measurements are an essential tool for the long-term clinical care of human immunodeficiency virus （HIV）-positive individuals. The gold standards in viral load instrumentation, however, are still too limited by their size, cost, and sophisticated operation for these measurements to be ubiquitous in remote settings with poor healthcare infrastructure, including parts of the world that are disproportionately affected by HIV infection. The challenge of developing a point-of-care platform capable of making viral load more accessible has been frequently approached but no solution has yet emerged that meets the practical requirements of low cost, portability, and ease-of-use. In this paper, we perform reverse-transcription loop-mediated isothermal amplification （RT-LAMP） on minimally processed HIV-spiked whole blood samples with a microfluidic and silicon microchip platform, and perform fluorescence measurements with a consumer smartphone. Our integrated assay shows amplification from as few as three viruses in a - 60 nL RT- LAMP droplet, corresponding to a whole blood concentration of 670 viruses per μL of whole blood. The technology contains greater power in a digital RT-LAMP approach that could be scaled up for the determination of viral load from a finger prick of blood in the clinical care of HIV-positive individuals. We demonstrate that all aspects of this viral load approach, from a drop of blood to imaging the RT-LAMP reaction, are compatible with lab-on-a-chip components and mobile instrumentation.展开更多
The tumor suppressor p53 is a multifunctional, highly regulated, and promoter-specific transcriptional factor that is uniquely sensitive to DNA damage and cellular stress signaling. The mechanisms by which p53 directs...The tumor suppressor p53 is a multifunctional, highly regulated, and promoter-specific transcriptional factor that is uniquely sensitive to DNA damage and cellular stress signaling. The mechanisms by which p53 directs a damaged cell down either a cell growth arrest or an apoptotic pathway remain poorly understood. Evidence suggests that the in vivo functions of p53 seem to balance the cell-fate choice with the type and severity of damage that occurs. The concept of antirepression, or inhibition of factors that normally keep p53 at bay, may help explain the physiological mechanisms for p53 activation. These factors also provide novel chemotherapeutic targets for the reactivation of p53 in tumors harboring a wild-type copy of the gene.展开更多
The ichnovirus TrIV, transmitted by the endoparasitic wasp Tranosema rostrale to its lepidopteran host during oviposition, replicates asymptomatically in wasp ovaries and causes physiological dysfunctions in parasitiz...The ichnovirus TrIV, transmitted by the endoparasitic wasp Tranosema rostrale to its lepidopteran host during oviposition, replicates asymptomatically in wasp ovaries and causes physiological dysfunctions in parasitized caterpillars. The need to identify ichnoviral genes responsible for disturbances induced in lepidopteran hosts has provided the impetus for the sequencing and annotation of ichnovirus genomes, including that of TrIV. In the latter, 86 putative genes were identified, including 35 that could be assigned to recognized ichnoviral gene families. With the aim of assessing the relative importance of each TrIV gene, as inferred from its level of expression, and evaluating the accuracy of the gene predictions made during genome annotation, the present study builds on an earlier qPCR quantification of transcript abundance of TrIV rep ORFs, in both lepidopteran and wasp hosts, extending it to other gene families as well as to a sample of unassigned ORFs. We show that the majority (91%) of putative ORFs assigned to known gene families are expressed in infected larvae, while this proportion is lower (67%) for a sample taken among the remaining ORFs. Selected members of the TrV and rep gene families are shown to be transcribed in infected larvae at much higher levels than genes from any other TrIV gene family, pointing to their likely involvement in host subjugation. In wasp ovaries, the transcriptional profile is dominated by a rep gene and a member of a newly described gene family encoding secreted proteins displaying a novel cysteine motif, which we identified among previously unassigned ORFs.展开更多
The study examined the effects of counselling on in-school adolescents about HIV/AIDS in Malaysia. A total of 100 male and female students were randomly chosen from three residential commercial areas located in Kuala ...The study examined the effects of counselling on in-school adolescents about HIV/AIDS in Malaysia. A total of 100 male and female students were randomly chosen from three residential commercial areas located in Kuala Lumpur in Malaysia. A questionnaire on HIV/AIDS symptoms was administered. The findings of the study indicated that two thirds of the interviewed adolescents have high desires to live longer on the earth. Also, adolescents do not associate high death rates of youths with HIV/AIDS symptoms. This report has implications for HIV/AIDS counselling in the Malaysian school system. This is supported by the fact that with the success of retrovirus therapy, many of the infected now live healthier lives and are pursuing a wider range of activities. Many HIV/AIDS infected people today can participate in undergoing their daily life activities, with a significant chance of living longer on the earth. The authors conclude that collaborative partnership between HIV/AIDS services and HIV counselling as part of the integrated system will provide early intervention services to boast relief of anxiety for the young people in Malaysia who already live with HIV/AIDS.展开更多
文摘Since transgene silencing was found in transgenic plants,many scholars have studied it extensively and considered that it has three functional mechanisms:post dependent gene silencing,transcriptional gene silencing,post transcriptional gene silencing.At the moment,people have mainly focused on the study of post transcriptional gene silencing and found its features:extensivity,conduction and peculiarity,also put forward some hypothesis for its mechanisms,for example,RNA threshold model,aberrant RNA model,inter or intra molecular base pairing model and so on.Furthermore,post transcriptional gene silencing is being applied in gene engineering of plants.Recently the people have found that post transcriptional gene silencing has bearing on capacity plants resisting virus.Many researchers have studied post transcriptional gene silencing,but there are some questions which need be solved in the future.This article summarizes progresses in features,mechanisms,applies of post transcriptional gene silencing about transgenic plants.
基金the National Basic Research Program of China (2004CB1175004) and the National Natural Science of Foundation of China, No. 30025034
文摘miRNAs are a class of small, ∽22nt, non-coding RNAs that negatively regulate gene expression at the posttranscriptional level. They play profound and pervasive roles in manipulating gene expression involved in cell development, proliferation and apoptosis in various eukaryotes, which, in theory, could provide an access to many human diseases in theory. Recent evidence demonstrates that aberrant miRNA expression is a hallmark of tumor development, revealing that miRNA genes could function as potential oncogenes and repressors in the human body. miRNAs can affect tumorigenesis mainly by interrupting the cell cycle at the cellular level and by interacting with signaling, oncogenes and with the response to environmental factors at the molecular level. The established miRNA expression signature could be a potent tool to diagnose and treat human cancers in the future.
文摘Hepatitis C virus （HCV） needs to tightly manipulate host defences in order to establish infection. The innate immune response slows down viral replication by activating cytokines such as the type Ⅰ interferons （IFN-α/ β）, which trigger the synthesis of antiviral proteins and modulate the adaptive immune system. HCV has therefore developed a number of countermeasures to stay ahead of the IFN system. Here, I will attempt to summarize the current state of research regarding IFN responses against HCV and the viral escape strategies. Particular emphasis will be put on the newly discovered mechanisms HCV employs to avoid the induction of IFN in infected cells.
基金financially supported by the National Natural Science Foundation of China(31270408)National High Technology Research and Development Program(863 Program)of China(2014AA022001)
文摘In this study, we compared the transcriptomes of Nannochloropsis oceanica cultured in f/2 medium prepared with seawater and freshwater, respectively, aiming to understand the acclimation mechanism of this alga to freshwater. Differentially expressed genes were mainly assigned to the degradation of cell components, ion transportation, and ribosomal biogenesis. These find- ings indicate that the algal cells degrade its components （mainly amino acids and fatty acids） to yield excessive energy （ATP） to maintain cellular ion （mainly K＋ and Ca〉） homeostasis, while the depletion of amino acids and ATP, and the reduction of ribosomes attenuate the protein translation and finally slow down the cell growth.
文摘The nuclear receptor PPARs are fundamentally important for energy homeostasis. Through their distinct yet overlapping functions and tissue distribution, the PPARs regulate many aspects of energy metabolism at the transcriptional level. Functional impairment or dysregulation of these receptors leads to a variety of metabolic diseases, while their ligands offer many metabolic benefits. Studies of these receptors have advanced our knowledge of the transcriptional basis of energy metabolism and helped us understand the pathogenic mechanisms of metabolic syndrome.
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.
基金supported by funding from the National Institutes of Health (NIH) Exploratory/Developmental Grant (R21) (AI106024)supported by a Ruth L.Kirschstein National Research Service Award for Individual Pred octoral MD/PhD and Other Dual Doctoral Degree Fellows (F30) (AI109825)
文摘Viral load measurements are an essential tool for the long-term clinical care of human immunodeficiency virus （HIV）-positive individuals. The gold standards in viral load instrumentation, however, are still too limited by their size, cost, and sophisticated operation for these measurements to be ubiquitous in remote settings with poor healthcare infrastructure, including parts of the world that are disproportionately affected by HIV infection. The challenge of developing a point-of-care platform capable of making viral load more accessible has been frequently approached but no solution has yet emerged that meets the practical requirements of low cost, portability, and ease-of-use. In this paper, we perform reverse-transcription loop-mediated isothermal amplification （RT-LAMP） on minimally processed HIV-spiked whole blood samples with a microfluidic and silicon microchip platform, and perform fluorescence measurements with a consumer smartphone. Our integrated assay shows amplification from as few as three viruses in a - 60 nL RT- LAMP droplet, corresponding to a whole blood concentration of 670 viruses per μL of whole blood. The technology contains greater power in a digital RT-LAMP approach that could be scaled up for the determination of viral load from a finger prick of blood in the clinical care of HIV-positive individuals. We demonstrate that all aspects of this viral load approach, from a drop of blood to imaging the RT-LAMP reaction, are compatible with lab-on-a-chip components and mobile instrumentation.
文摘The tumor suppressor p53 is a multifunctional, highly regulated, and promoter-specific transcriptional factor that is uniquely sensitive to DNA damage and cellular stress signaling. The mechanisms by which p53 directs a damaged cell down either a cell growth arrest or an apoptotic pathway remain poorly understood. Evidence suggests that the in vivo functions of p53 seem to balance the cell-fate choice with the type and severity of damage that occurs. The concept of antirepression, or inhibition of factors that normally keep p53 at bay, may help explain the physiological mechanisms for p53 activation. These factors also provide novel chemotherapeutic targets for the reactivation of p53 in tumors harboring a wild-type copy of the gene.
基金Grants from the Canadian Forest Service(CFS) and a Discovery grant from the Natural Sciences and Engineering Research Council of Canada to MC
文摘The ichnovirus TrIV, transmitted by the endoparasitic wasp Tranosema rostrale to its lepidopteran host during oviposition, replicates asymptomatically in wasp ovaries and causes physiological dysfunctions in parasitized caterpillars. The need to identify ichnoviral genes responsible for disturbances induced in lepidopteran hosts has provided the impetus for the sequencing and annotation of ichnovirus genomes, including that of TrIV. In the latter, 86 putative genes were identified, including 35 that could be assigned to recognized ichnoviral gene families. With the aim of assessing the relative importance of each TrIV gene, as inferred from its level of expression, and evaluating the accuracy of the gene predictions made during genome annotation, the present study builds on an earlier qPCR quantification of transcript abundance of TrIV rep ORFs, in both lepidopteran and wasp hosts, extending it to other gene families as well as to a sample of unassigned ORFs. We show that the majority (91%) of putative ORFs assigned to known gene families are expressed in infected larvae, while this proportion is lower (67%) for a sample taken among the remaining ORFs. Selected members of the TrV and rep gene families are shown to be transcribed in infected larvae at much higher levels than genes from any other TrIV gene family, pointing to their likely involvement in host subjugation. In wasp ovaries, the transcriptional profile is dominated by a rep gene and a member of a newly described gene family encoding secreted proteins displaying a novel cysteine motif, which we identified among previously unassigned ORFs.
文摘The study examined the effects of counselling on in-school adolescents about HIV/AIDS in Malaysia. A total of 100 male and female students were randomly chosen from three residential commercial areas located in Kuala Lumpur in Malaysia. A questionnaire on HIV/AIDS symptoms was administered. The findings of the study indicated that two thirds of the interviewed adolescents have high desires to live longer on the earth. Also, adolescents do not associate high death rates of youths with HIV/AIDS symptoms. This report has implications for HIV/AIDS counselling in the Malaysian school system. This is supported by the fact that with the success of retrovirus therapy, many of the infected now live healthier lives and are pursuing a wider range of activities. Many HIV/AIDS infected people today can participate in undergoing their daily life activities, with a significant chance of living longer on the earth. The authors conclude that collaborative partnership between HIV/AIDS services and HIV counselling as part of the integrated system will provide early intervention services to boast relief of anxiety for the young people in Malaysia who already live with HIV/AIDS.
