WorldWideScience

Sample records for bacterial factors regulating

  1. A bacteriophage transcription regulator inhibits bacterial transcription initiation by σ-factor displacement

    OpenAIRE

    Liu, Bing; Shadrin, Andrey; Sheppard, Carol; Mekler, Vladimir; Xu, Yingqi; Severinov, Konstantin; Matthews, Steve; Wigneshweraraj, Sivaramesh

    2014-01-01

    Bacteriophages (phages) appropriate essential processes of bacterial hosts to benefit their own development. The multisubunit bacterial RNA polymerase (RNAp) enzyme, which catalyses DNA transcription, is targeted by phage-encoded transcription regulators that selectively modulate its activity. Here, we describe the structural and mechanistic basis for the inhibition of bacterial RNAp by the transcription regulator P7 encoded by Xanthomonas oryzae phage Xp10. We reveal that P7 uses a two-step ...

  2. Arabidopsis Clade I TGA Factors Regulate Apoplastic Defences against the Bacterial Pathogen Pseudomonas syringae through Endoplasmic Reticulum-Based Processes

    OpenAIRE

    Wang, Lipu; Fobert, Pierre R.

    2013-01-01

    During the plant immune response, large-scale transcriptional reprogramming is modulated by numerous transcription (co) factors. The Arabidopsis basic leucine zipper transcription factors TGA1 and TGA4, which comprise the clade I TGA factors, have been shown to positively contribute to disease resistance against virulent strains of the bacterial pathogen Pseudomonas syringae . Despite physically interacting with the key immune regulator, NON-EXPRESSOR OF PATHOGENESIS-RELATED GENES 1 (NPR1), f...

  3. Cold Plasma Inactivation of Bacterial Biofilms and Reduction of Quorum Sensing Regulated Virulence Factors.

    Directory of Open Access Journals (Sweden)

    Dana Ziuzina

    Full Text Available The main objectives of this work were to investigate the effect of atmospheric cold plasma (ACP against a range of microbial biofilms commonly implicated in foodborne and healthcare associated human infections and against P. aeruginosa quorum sensing (QS-regulated virulence factors, such as pyocyanin, elastase (Las B and biofilm formation capacity post-ACP treatment. The effect of processing factors, namely treatment time and mode of plasma exposure on antimicrobial activity of ACP were also examined. Antibiofilm activity was assessed for E. coli, L. monocytogenes and S. aureus in terms of reduction of culturability and retention of metabolic activity using colony count and XTT assays, respectively. All samples were treated 'inpack' using sealed polypropylene containers with a high voltage dielectric barrier discharge ACP generated at 80 kV for 0, 60, 120 and 300 s and a post treatment storage time of 24 h. According to colony counts, ACP treatment for 60 s reduced populations of E. coli to undetectable levels, whereas 300 s was necessary to significantly reduce populations of L. monocytogenes and S. aureus biofilms. The results obtained from XTT assay indicated possible induction of viable but non culturable state of bacteria. With respect to P. aeruginosa QS-related virulence factors, the production of pyocyanin was significantly inhibited after short treatment times, but reduction of elastase was notable only after 300 s and no reduction in actual biofilm formation was achieved post-ACP treatment. Importantly, reduction of virulence factors was associated with reduction of the cytotoxic effects of the bacterial supernatant on CHO-K1 cells, regardless of mode and duration of treatment. The results of this study point to ACP technology as an effective strategy for inactivation of established biofilms and may play an important role in attenuation of virulence of pathogenic bacteria. Further investigation is warranted to propose direct evidence

  4. Cold Plasma Inactivation of Bacterial Biofilms and Reduction of Quorum Sensing Regulated Virulence Factors

    Science.gov (United States)

    Ziuzina, Dana; Boehm, Daniela; Patil, Sonal; Cullen, P. J.; Bourke, Paula

    2015-01-01

    The main objectives of this work were to investigate the effect of atmospheric cold plasma (ACP) against a range of microbial biofilms commonly implicated in foodborne and healthcare associated human infections and against P. aeruginosa quorum sensing (QS)-regulated virulence factors, such as pyocyanin, elastase (Las B) and biofilm formation capacity post-ACP treatment. The effect of processing factors, namely treatment time and mode of plasma exposure on antimicrobial activity of ACP were also examined. Antibiofilm activity was assessed for E. coli, L. monocytogenes and S. aureus in terms of reduction of culturability and retention of metabolic activity using colony count and XTT assays, respectively. All samples were treated ‘inpack’ using sealed polypropylene containers with a high voltage dielectric barrier discharge ACP generated at 80 kV for 0, 60, 120 and 300 s and a post treatment storage time of 24 h. According to colony counts, ACP treatment for 60 s reduced populations of E. coli to undetectable levels, whereas 300 s was necessary to significantly reduce populations of L. monocytogenes and S. aureus biofilms. The results obtained from XTT assay indicated possible induction of viable but non culturable state of bacteria. With respect to P. aeruginosa QS-related virulence factors, the production of pyocyanin was significantly inhibited after short treatment times, but reduction of elastase was notable only after 300 s and no reduction in actual biofilm formation was achieved post-ACP treatment. Importantly, reduction of virulence factors was associated with reduction of the cytotoxic effects of the bacterial supernatant on CHO-K1 cells, regardless of mode and duration of treatment. The results of this study point to ACP technology as an effective strategy for inactivation of established biofilms and may play an important role in attenuation of virulence of pathogenic bacteria. Further investigation is warranted to propose direct evidence for the

  5. Identification of host cytosolic sensors and bacterial factors regulating the type I interferon response to Legionella pneumophila.

    Directory of Open Access Journals (Sweden)

    Kathryn M Monroe

    2009-11-01

    Full Text Available Legionella pneumophila is a gram-negative bacterial pathogen that replicates in host macrophages and causes a severe pneumonia called Legionnaires' Disease. The innate immune response to L. pneumophila remains poorly understood. Here we focused on identifying host and bacterial factors involved in the production of type I interferons (IFN in response to L. pneumophila. It was previously suggested that the delivery of L. pneumophila DNA to the host cell cytosol is the primary signal that induces the type I IFN response. However, our data are not easily reconciled with this model. We provide genetic evidence that two RNA-sensing proteins, RIG-I and MDA5, participate in the IFN response to L. pneumophila. Importantly, these sensors do not seem to be required for the IFN response to L. pneumophila DNA, whereas we found that RIG-I was required for the response to L. pneumophila RNA. Thus, we hypothesize that bacterial RNA, or perhaps an induced host RNA, is the primary stimulus inducing the IFN response to L. pneumophila. Our study also identified a secreted effector protein, SdhA, as a key suppressor of the IFN response to L. pneumophila. Although viral suppressors of cytosolic RNA-sensing pathways have been previously identified, analogous bacterial factors have not been described. Thus, our results provide new insights into the molecular mechanisms by which an intracellular bacterial pathogen activates and also represses innate immune responses.

  6. Interleukin-10 Regulates the Tissue Factor Activity of Monocytes in an In Vitro Model of Bacterial Endocarditis

    OpenAIRE

    Veltrop, Marcel H. A. M.; Langermans, Jan A. M.; Thompson, Jan; Bancsi, Maurice J. L. M. F.

    2001-01-01

    Monocytes are important effector cells in the pathogenesis of bacterial endocarditis since they provide the tissue factor that activates the coagulation system and maintains established vegetations. Monocytes secrete cytokines that can modulate monocyte tissue factor activity (TFA), thereby affecting the formation and maintenance of vegetations. In this study, we show that monocytes cultured for 4 h on a Streptococcus sanguis-infected fibrin matrix mimicking the in vivo vegetational surface e...

  7. Dynamics of bacterial gene regulation

    Science.gov (United States)

    Narang, Atul

    2009-03-01

    The phenomenon of diauxic growth is a classical problem of bacterial gene regulation. The most well studied example of this phenomenon is the glucose-lactose diauxie, which occurs because the expression of the lac operon is strongly repressed in the presence of glucose. This repression is often explained by appealing to molecular mechanisms such as cAMP activation and inducer exclusion. I will begin by analyzing data showing that these molecular mechanisms cannot explain the strong lac repression because they exert a relatively weak effect. I will then present a minimal model accounting only for enzyme induction and dilution, which yields strong repression despite the absence of catabolite repression and inducer exclusion. The model also explains the growth patterns observed in batch and continuous cultures of various bacterial strains and substrate mixtures. The talk will conclude with a discussion of the experimental evidence regarding positive feedback, the key component of the minimal model.

  8. Regulation of Bacterial Peptidoglycan Polymerization.

    Science.gov (United States)

    Arthur, Michel

    2016-07-01

    How bacterial cells control the activity of peptidoglycan polymerases has remained mysterious. Biochemical characterization of derivatives of penicillin-binding protein PBP1b that are functional in the absence of lipoprotein LpoB provides evidence for allosteric control of PBP1b glycosyltransferase activity via binding of LpoB to the PBP1b UBH1 domain. PMID:27236859

  9. Hypoxia-inducible Factor-dependent Regulation of Platelet-activating Factor Receptor as a Route for Gram-Positive Bacterial Translocation across Epithelia

    OpenAIRE

    Keely, Simon; Glover, Louise E.; Weissmueller, Thomas; MacManus, Christopher F.; Fillon, Sophie; Fennimore, Blair; Colgan, Sean P.

    2010-01-01

    Mucosal surfaces, such as the lung and intestine, are lined by a monolayer of epithelia that provides tissue barrier and transport function. It is recently appreciated that a common feature of inflammatory processes within the mucosa is hypoxia (so-called inflammatory hypoxia). Given the strong association between bacterial translocation and mucosal inflammatory disease, we hypothesized that intestinal epithelial hypoxia influences bacterial translocation. Initial studies revealed that exposu...

  10. Plant Natural Products Targeting Bacterial Virulence Factors.

    Science.gov (United States)

    Silva, Laura Nunes; Zimmer, Karine Rigon; Macedo, Alexandre José; Trentin, Danielle Silva

    2016-08-24

    Decreased antimicrobial efficiency has become a global public health issue. The paucity of new antibacterial drugs is evident, and the arsenal against infectious diseases needs to be improved urgently. The selection of plants as a source of prototype compounds is appropriate, since plant species naturally produce a wide range of secondary metabolites that act as a chemical line of defense against microorganisms in the environment. Although traditional approaches to combat microbial infections remain effective, targeting microbial virulence rather than survival seems to be an exciting strategy, since the modulation of virulence factors might lead to a milder evolutionary pressure for the development of resistance. Additionally, anti-infective chemotherapies may be successfully achieved by combining antivirulence and conventional antimicrobials, extending the lifespan of these drugs. This review presents an updated discussion of natural compounds isolated from plants with chemically characterized structures and activity against the major bacterial virulence factors: quorum sensing, bacterial biofilms, bacterial motility, bacterial toxins, bacterial pigments, bacterial enzymes, and bacterial surfactants. Moreover, a critical analysis of the most promising virulence factors is presented, highlighting their potential as targets to attenuate bacterial virulence. The ongoing progress in the field of antivirulence therapy may therefore help to translate this promising concept into real intervention strategies in clinical areas. PMID:27437994

  11. Regulation of Bacterial Virulence by Csr (Rsm) Systems

    OpenAIRE

    Vakulskas, Christopher A.; Potts, Anastasia H.; Babitzke, Paul; Ahmer, Brian M. M.; Romeo, Tony

    2015-01-01

    Most bacterial pathogens have the remarkable ability to flourish in the external environment and in specialized host niches. This ability requires their metabolism, physiology, and virulence factors to be responsive to changes in their surroundings. It is no surprise that the underlying genetic circuitry that supports this adaptability is multilayered and exceedingly complex. Studies over the past 2 decades have established that the CsrA/RsmA proteins, global regulators of posttranscriptional...

  12. Evolutionary rewiring and reprogramming of bacterial transcription regulation

    Institute of Scientific and Technical Information of China (English)

    Li Wang; Fang-Fang Wang; Wei Qian

    2011-01-01

    Rewiring and reprogramming of transcriptional regulation took place during bacterial speciation. The mechanistic alterations among transcription factors, cis-regulatory elements and target genes confer bacteria novel ability to adapt to stochastic environmental changes. This process is critical to their survival, especially for bacterial pathogens subjected to accelerated evolution. In the past two decades, the investigators not only completed the sequences of numerous bacterial genomes, but also made great progress in understanding the molecular basis of evolution. Here we briefly reviewed the current knowledge on the mechanistic changes among orthologous, paralogous and xenogenic regulatory circuits, which were caused by genetic recombinations such as gene duplication, horizontal gene transfer, transposable elements and different genetic contexts. We also discussed the potential impact of this area on theoretical and applied studies of microbes.

  13. Factors influencing bacterial adhesion to contact lenses

    OpenAIRE

    Dutta, Debarun; Cole, Nerida; Willcox, Mark

    2012-01-01

    The process of any contact lens related keratitis generally starts with the adhesion of opportunistic pathogens to contact lens surface. This article focuses on identifying the factors which have been reported to affect bacterial adhesion to contact lenses. Adhesion to lenses differs between various genera/species/strains of bacteria. Pseudomonas aeruginosa, which is the predominant causative organism, adheres in the highest numbers to both hydrogel and silicone hydrogel lenses in vitro. The ...

  14. Regulation of bacterial virulence by Csr (Rsm) systems.

    Science.gov (United States)

    Vakulskas, Christopher A; Potts, Anastasia H; Babitzke, Paul; Ahmer, Brian M M; Romeo, Tony

    2015-06-01

    Most bacterial pathogens have the remarkable ability to flourish in the external environment and in specialized host niches. This ability requires their metabolism, physiology, and virulence factors to be responsive to changes in their surroundings. It is no surprise that the underlying genetic circuitry that supports this adaptability is multilayered and exceedingly complex. Studies over the past 2 decades have established that the CsrA/RsmA proteins, global regulators of posttranscriptional gene expression, play important roles in the expression of virulence factors of numerous proteobacterial pathogens. To accomplish these tasks, CsrA binds to the 5' untranslated and/or early coding regions of mRNAs and alters translation, mRNA turnover, and/or transcript elongation. CsrA activity is regulated by noncoding small RNAs (sRNAs) that contain multiple CsrA binding sites, which permit them to sequester multiple CsrA homodimers away from mRNA targets. Environmental cues sensed by two-component signal transduction systems and other regulatory factors govern the expression of the CsrA-binding sRNAs and, ultimately, the effects of CsrA on secretion systems, surface molecules and biofilm formation, quorum sensing, motility, pigmentation, siderophore production, and phagocytic avoidance. This review presents the workings of the Csr system, the paradigm shift that it generated for understanding posttranscriptional regulation, and its roles in virulence networks of animal and plant pathogens. PMID:25833324

  15. Septins regulate bacterial entry into host cells.

    Directory of Open Access Journals (Sweden)

    Serge Mostowy

    Full Text Available BACKGROUND: Septins are conserved GTPases that form filaments and are required in many organisms for several processes including cytokinesis. We previously identified SEPT9 associated with phagosomes containing latex beads coated with the Listeria surface protein InlB. METHODOLOGY/PRINCIPAL FINDINGS: Here, we investigated septin function during entry of invasive bacteria in non-phagocytic mammalian cells. We found that SEPT9, and its interacting partners SEPT2 and SEPT11, are recruited as collars next to actin at the site of entry of Listeria and Shigella. SEPT2-depletion by siRNA decreased bacterial invasion, suggesting that septins have roles during particle entry. Incubating cells with InlB-coated beads confirmed an essential role for SEPT2. Moreover, SEPT2-depletion impaired InlB-mediated stimulation of Met-dependent signaling as shown by FRET. CONCLUSIONS/SIGNIFICANCE: Together these findings highlight novel roles for SEPT2, and distinguish the roles of septin and actin in bacterial entry.

  16. Fucose Sensing Regulates Bacterial Intestinal Colonization

    OpenAIRE

    Pacheco, Alline R.; Curtis, Meredith M.; Ritchie, Jennifer M; Munera, Diana; Matthew K Waldor; Moreira, Cristiano G.; Sperandio, Vanessa

    2012-01-01

    The mammalian gastrointestinal (GI) tract provides a complex and competitive environment for the microbiota 1 . Successful colonization by pathogens depends on scavenging nutrients, sensing chemical signals, competing with the resident bacteria, and precisely regulating expression of virulence genes 2 . The GI pathogen enterohemorrhagic E.coli (EHEC) relies on inter-kingdom chemical sensing systems to regulate virulence gene expression 3–4 . Here we show that these systems control the express...

  17. Serine/threonine/tyrosine phosphorylation regulates DNA binding of bacterial transcriptional regulators

    DEFF Research Database (Denmark)

    Kalantari, Aida; Derouiche, Abderahmane; Shi, Lei; Mijakovic, Ivan

    2015-01-01

    Reversible phosphorylation of bacterial transcriptional regulators (TRs) belonging to the family of two-component systems (TCSs) is a well-established mechanism for regulating gene expression. Recent evidence points to the fact that reversible phosphorylation of bacterial TRs on other types of....... Here, we present an overview of different classes of bacterial TR phosphorylated and regulated by serine/threonine and tyrosine kinases. Particular attention is given to examples when serine/threonine and tyrosine kinases interact with TCSs, phosphorylating either the histidine kinases or the response...... regulators. We argue that these promiscuous kinases connect several signal transduction pathways and serve the role of signal integration....

  18. FACTORS REGULATING LIBERAL TRANSLATION

    Institute of Scientific and Technical Information of China (English)

    龚海红

    2012-01-01

    Literal translation and liberal translation are two important methods and both play key roles in translation.However,some textbooks say that most translations are literal translations while others maintain most are liberal ones,besides,some others suggest a combination of the two.This paper focuses on the facts that regulate liberal translation.Because of the differences in culture,society,history,geography,and so on,there exists a great difference between Chinese language and English language,which does naturally lead to the liberal translation.

  19. Control of intestinal bacterial proliferation in regulation of lifespan in Caenorhabditis elegans

    Directory of Open Access Journals (Sweden)

    Portal-Celhay Cynthia

    2012-03-01

    Full Text Available Abstract Background A powerful approach to understanding complex processes such as aging is to use model organisms amenable to genetic manipulation, and to seek relevant phenotypes to measure. Caenorhabditis elegans is particularly suited to studies of aging, since numerous single-gene mutations have been identified that affect its lifespan; it possesses an innate immune system employing evolutionarily conserved signaling pathways affecting longevity. As worms age, bacteria accumulate in the intestinal tract. However, quantitative relationships between worm genotype, lifespan, and intestinal lumen bacterial load have not been examined. We hypothesized that gut immunity is less efficient in older animals, leading to enhanced bacterial accumulation, reducing longevity. To address this question, we evaluated the ability of worms to control bacterial accumulation as a functional marker of intestinal immunity. Results We show that as adult worms age, several C. elegans genotypes show diminished capacity to control intestinal bacterial accumulation. We provide evidence that intestinal bacterial load, regulated by gut immunity, is an important causative factor of lifespan determination; the effects are specified by bacterial strain, worm genotype, and biologic age, all acting in concert. Conclusions In total, these studies focus attention on the worm intestine as a locus that influences longevity in the presence of an accumulating bacterial population. Further studies defining the interplay between bacterial species and host immunity in C. elegans may provide insights into the general mechanisms of aging and age-related diseases.

  20. Bacterial Sphingomyelinases and Phospholipases as Virulence Factors.

    Science.gov (United States)

    Flores-Díaz, Marietta; Monturiol-Gross, Laura; Naylor, Claire; Alape-Girón, Alberto; Flieger, Antje

    2016-09-01

    Bacterial sphingomyelinases and phospholipases are a heterogeneous group of esterases which are usually surface associated or secreted by a wide variety of Gram-positive and Gram-negative bacteria. These enzymes hydrolyze sphingomyelin and glycerophospholipids, respectively, generating products identical to the ones produced by eukaryotic enzymes which play crucial roles in distinct physiological processes, including membrane dynamics, cellular signaling, migration, growth, and death. Several bacterial sphingomyelinases and phospholipases are essential for virulence of extracellular, facultative, or obligate intracellular pathogens, as these enzymes contribute to phagosomal escape or phagosomal maturation avoidance, favoring tissue colonization, infection establishment and progression, or immune response evasion. This work presents a classification proposal for bacterial sphingomyelinases and phospholipases that considers not only their enzymatic activities but also their structural aspects. An overview of the main physiopathological activities is provided for each enzyme type, as are examples in which inactivation of a sphingomyelinase- or a phospholipase-encoding gene impairs the virulence of a pathogen. The identification of sphingomyelinases and phospholipases important for bacterial pathogenesis and the development of inhibitors for these enzymes could generate candidate vaccines and therapeutic agents, which will diminish the impacts of the associated human and animal diseases. PMID:27307578

  1. Exploiting the commons: cyclic diguanylate regulation of bacterial exopolysaccharide production.

    Science.gov (United States)

    Pérez-Mendoza, Daniel; Sanjuán, Juan

    2016-04-01

    Nowadays, there is increasing interest for bacterial polysaccharides in a wide variety of industrial sectors. This is due to their chemical and reological properties, and also the possibility to be obtained by fermentation processes. Biosynthesis of a growing number of exopolysaccharides (EPS) has been reported to be regulated by the ubiquitous second messenger c-di-GMP in a limited number of bacterial species. Since most bacteria are yet unexplored, it is likely that an unsuspected number and variety of EPS structures activated by c-di-GMP await to be uncovered. In the search of new EPS, manipulation of bacterial c-di-GMP metabolism can be combined with high throughput approaches for screening of large collections of bacteria. In addition, c-di-GMP activation of EPS production and promotion of cell aggregation may have direct applications in environmental industries related with biofuel production or wastewater treatments. PMID:26773798

  2. Bacterial Sigma Factors as Targets for Engineered or Synthetic Transcriptional Control

    Science.gov (United States)

    Tripathi, Lakshmi; Zhang, Yan; Lin, Zhanglin

    2014-01-01

    Sigma (σ) factors are the predominant constituents of transcription regulation in bacteria. σ Factors recruit the core RNA polymerase to recognize promoters with specific DNA sequences. Recently, engineering of transcriptional regulators has become a significant tool for strain engineering. The present review summarizes the recent advances in σ factor based engineering or synthetic design. The manipulation of σ factors presents insights into the bacterial stress tolerance and metabolite productivity. We envision more synthetic design based on σ factors that can be used to tune the regulatory network of bacteria. PMID:25232540

  3. Bacterial sigma factors as targets for engineered or synthetic transcriptional control

    Directory of Open Access Journals (Sweden)

    Lakshmi eTripathi

    2014-09-01

    Full Text Available Sigma (σ factors are the predominant constituents of transcription regulation in bacteria. σ factors recruit the core RNA polymerase (RNAP to recognize promoters with specific DNA sequences. Recently engineering of transcriptional regulators has become a significant tool for strain engineering. The present review summarizes the recent advances in σ factor based engineering or synthetic design. The manipulation of σ factors presents insights into the bacterial stress tolerance and metabolite productivity. We envision more synthetic design based on σ factors that can be used to tune the regulatory network of bacteria.

  4. Interplay between genetic regulation of phosphate homeostasis and bacterial virulence

    OpenAIRE

    Chekabab, Samuel Mohammed; Harel, Josée; Dozois, Charles M.

    2014-01-01

    Bacterial pathogens, including those of humans, animals, and plants, encounter phosphate (Pi)-limiting or Pi-rich environments in the host, depending on the site of infection. The environmental Pi-concentration results in modulation of expression of the Pho regulon that allows bacteria to regulate phosphate assimilation pathways accordingly. In many cases, modulation of Pho regulon expression also results in concomitant changes in virulence phenotypes. Under Pi-limiting conditions, bacteria u...

  5. Single-taxon field measurements of bacterial gene regulation controlling DMSP fate.

    Science.gov (United States)

    Varaljay, Vanessa A; Robidart, Julie; Preston, Christina M; Gifford, Scott M; Durham, Bryndan P; Burns, Andrew S; Ryan, John P; Marin, Roman; Kiene, Ronald P; Zehr, Jonathan P; Scholin, Christopher A; Moran, Mary Ann

    2015-07-01

    The 'bacterial switch' is a proposed regulatory point in the global sulfur cycle that routes dimethylsulfoniopropionate (DMSP) to two fundamentally different fates in seawater through genes encoding either the cleavage or demethylation pathway, and affects the flux of volatile sulfur from ocean surface waters to the atmosphere. Yet which ecological or physiological factors might control the bacterial switch remains a topic of considerable debate. Here we report the first field observations of dynamic changes in expression of DMSP pathway genes by a single marine bacterial species in its natural environment. Detection of taxon-specific gene expression in Roseobacter species HTCC2255 during a month-long deployment of an autonomous ocean sensor in Monterey Bay, CA captured in situ regulation of the first gene in each DMSP pathway (dddP and dmdA) that corresponded with shifts in the taxonomy of the phytoplankton community. Expression of the demethylation pathway was relatively greater during a high-DMSP-producing dinoflagellate bloom, and expression of the cleavage pathway was greater in the presence of a mixed diatom and dinoflagellate community [corrected].These field data fit the prevailing hypothesis for bacterial DMSP gene regulation based on bacterial sulfur demand, but also suggest a modification involving oxidative stress response, evidenced as upregulation of catalase via katG, when DMSP is demethylated. PMID:25700338

  6. Factors that influence the speed of bacterial wood degradation

    NARCIS (Netherlands)

    Klaassen, R.K.W.M.; Overeem, van B.S.

    2012-01-01

    Bacterial wood decay is a serious threat to the many wooden foundation piles in the Netherlands. In order to learn more about the factors that influence the process of decay, approx. 2000 wood samples taken from Amsterdam piles heads were analysed on type and degree of decay and for 59 extracted pil

  7. DgcA, a diguanylate cyclase from Xanthomonas oryzae pv. oryzae regulates bacterial pathogenicity on rice

    Science.gov (United States)

    Su, Jianmei; Zou, Xia; Huang, Liangbo; Bai, Tenglong; Liu, Shu; Yuan, Meng; Chou, Shan-Ho; He, Ya-Wen; Wang, Haihong; He, Jin

    2016-01-01

    Xanthomonas oryzae pv. oryzae (Xoo) is the causal agent of rice blight disease as well as a serious phytopathogen worldwide. It is also one of the model organisms for studying bacteria-plant interactions. Current progress in bacterial signal transduction pathways has identified cyclic di-GMP as a major second messenger molecule in controlling Xanthomonas pathogenicity. However, it still remains largely unclear how c-di-GMP regulates the secretion of bacterial virulence factors in Xoo. In this study, we focused on the important roles played by DgcA (XOO3988), one of our previously identified diguanylate cyclases in Xoo, through further investigating the phenotypes of several dgcA-related mutants, namely, the dgcA-knockout mutant ΔdgcA, the dgcA overexpression strain OdgcA, the dgcA complemented strain CdgcA and the wild-type strain. The results showed that dgcA negatively affected virulence, EPS production, bacterial autoaggregation and motility, but positively triggered biofilm formation via modulating the intracellular c-di-GMP levels. RNA-seq data further identified 349 differentially expressed genes controlled by DgcA, providing a foundation for a more solid understanding of the signal transduction pathways in Xoo. Collectively, the present study highlights DgcA as a major regulator of Xoo virulence, and can serve as a potential target for preventing rice blight diseases. PMID:27193392

  8. DgcA, a diguanylate cyclase from Xanthomonas oryzae pv. oryzae regulates bacterial pathogenicity on rice.

    Science.gov (United States)

    Su, Jianmei; Zou, Xia; Huang, Liangbo; Bai, Tenglong; Liu, Shu; Yuan, Meng; Chou, Shan-Ho; He, Ya-Wen; Wang, Haihong; He, Jin

    2016-01-01

    Xanthomonas oryzae pv. oryzae (Xoo) is the causal agent of rice blight disease as well as a serious phytopathogen worldwide. It is also one of the model organisms for studying bacteria-plant interactions. Current progress in bacterial signal transduction pathways has identified cyclic di-GMP as a major second messenger molecule in controlling Xanthomonas pathogenicity. However, it still remains largely unclear how c-di-GMP regulates the secretion of bacterial virulence factors in Xoo. In this study, we focused on the important roles played by DgcA (XOO3988), one of our previously identified diguanylate cyclases in Xoo, through further investigating the phenotypes of several dgcA-related mutants, namely, the dgcA-knockout mutant ΔdgcA, the dgcA overexpression strain OdgcA, the dgcA complemented strain CdgcA and the wild-type strain. The results showed that dgcA negatively affected virulence, EPS production, bacterial autoaggregation and motility, but positively triggered biofilm formation via modulating the intracellular c-di-GMP levels. RNA-seq data further identified 349 differentially expressed genes controlled by DgcA, providing a foundation for a more solid understanding of the signal transduction pathways in Xoo. Collectively, the present study highlights DgcA as a major regulator of Xoo virulence, and can serve as a potential target for preventing rice blight diseases. PMID:27193392

  9. Ndk, a novel host-responsive regulator, negatively regulates bacterial virulence through quorum sensing in Pseudomonas aeruginosa

    Science.gov (United States)

    Yu, Hua; Xiong, Junzhi; Zhang, Rong; Hu, Xiaomei; Qiu, Jing; Zhang, Di; Xu, Xiaohui; Xin, Rong; He, Xiaomei; Xie, Wei; Sheng, Halei; Chen, Qian; Zhang, Le; Rao, Xiancai; Zhang, Kebin

    2016-01-01

    Pathogenic bacteria could adjust gene expression to enable their survival in the distinct host environment. However, the mechanism by which bacteria adapt to the host environment is not well described. In this study, we demonstrated that nucleoside diphosphate kinase (Ndk) of Pseudomonas aeruginosa is critical for adjusting the bacterial virulence determinants during infection. Ndk expression was down-regulated in the pulmonary alveoli of a mouse model of acute pneumonia. Knockout of ndk up-regulated transcription factor ExsA-mediated T3S regulon expression and decreased exoproduct-related gene expression through the inhibition of the quorum sensing hierarchy. Moreover, in vitro and in vivo studies demonstrated that the ndk mutant exhibits enhanced cytotoxicity and host pathogenicity by increasing T3SS proteins. Taken together, our data reveal that ndk is a critical novel host-responsive gene required for coordinating P. aeruginosa virulence upon acute infection. PMID:27345215

  10. Ndk, a novel host-responsive regulator, negatively regulates bacterial virulence through quorum sensing in Pseudomonas aeruginosa.

    Science.gov (United States)

    Yu, Hua; Xiong, Junzhi; Zhang, Rong; Hu, Xiaomei; Qiu, Jing; Zhang, Di; Xu, Xiaohui; Xin, Rong; He, Xiaomei; Xie, Wei; Sheng, Halei; Chen, Qian; Zhang, Le; Rao, Xiancai; Zhang, Kebin

    2016-01-01

    Pathogenic bacteria could adjust gene expression to enable their survival in the distinct host environment. However, the mechanism by which bacteria adapt to the host environment is not well described. In this study, we demonstrated that nucleoside diphosphate kinase (Ndk) of Pseudomonas aeruginosa is critical for adjusting the bacterial virulence determinants during infection. Ndk expression was down-regulated in the pulmonary alveoli of a mouse model of acute pneumonia. Knockout of ndk up-regulated transcription factor ExsA-mediated T3S regulon expression and decreased exoproduct-related gene expression through the inhibition of the quorum sensing hierarchy. Moreover, in vitro and in vivo studies demonstrated that the ndk mutant exhibits enhanced cytotoxicity and host pathogenicity by increasing T3SS proteins. Taken together, our data reveal that ndk is a critical novel host-responsive gene required for coordinating P. aeruginosa virulence upon acute infection. PMID:27345215

  11. Factors that regulate embryonic gustatory development

    Directory of Open Access Journals (Sweden)

    Krimm Robin F

    2007-09-01

    Full Text Available Abstract Numerous molecular factors orchestrate the development of the peripheral taste system. The unique anatomy/function of the taste system makes this system ideal for understanding the mechanisms by which these factors function; yet the taste system is underutilized for this role. This review focuses on some of the many factors that are known to regulate gustatory development, and discusses a few topics where more work is needed. Some attention is given to factors that regulate epibranchial placode formation, since gustatory neurons are thought to be primarily derived from this region. Epibranchial placodes appear to arise from a pan-placodal region and a number of regulatory factors control the differentiation of individual placodes. Gustatory neuron differentiation is regulated by a series of transcription factors and perhaps bone morphongenic proteins (BMP. As neurons differentiate, they also proliferate such that their numbers exceed those in the adult, and this is followed by developmental death. Some of these cell-cycling events are regulated by neurotrophins. After gustatory neurons become post-mitotic, axon outgrowth occurs. Axons are guided by multiple chemoattractive and chemorepulsive factors, including semaphorins, to the tongue epithelium. Brain derived neurotrophic factor (BDNF, functions as a targeting factor in the final stages of axon guidance and is required for gustatory axons to find and innervate taste epithelium. Numerous factors are involved in the development of gustatory papillae including Sox-2, Sonic hedge hog and Wnt-β-catenin signaling. It is likely that just as many factors regulate taste bud differentiation; however, these factors have not yet been identified. Studies examining the molecular factors that regulate terminal field formation in the nucleus of the solitary tract are also lacking. However, it is possible that some of the factors that regulate geniculate ganglion development, outgrowth, guidance and

  12. Structure and function of a spectrin-like regulator of bacterial cytokinesis

    Science.gov (United States)

    Cleverley, Robert M.; Barrett, Jeffrey R.; Baslé, Arnaud; Bui, Nhat Khai; Hewitt, Lorraine; Solovyova, Alexandra; Xu, Zhi-Qiang; Daniel, Richard A.; Dixon, Nicholas E.; Harry, Elizabeth J.; Oakley, Aaron J.; Vollmer, Waldemar; Lewis, Richard J.

    2014-11-01

    Bacterial cell division is facilitated by a molecular machine—the divisome—that assembles at mid-cell in dividing cells. The formation of the cytokinetic Z-ring by the tubulin homologue FtsZ is regulated by several factors, including the divisome component EzrA. Here we describe the structure of the 60-kDa cytoplasmic domain of EzrA, which comprises five linear repeats of an unusual triple helical bundle. The EzrA structure is bent into a semicircle, providing the protein with the potential to interact at both N- and C-termini with adjacent membrane-bound divisome components. We also identify at least two binding sites for FtsZ on EzrA and map regions of EzrA that are responsible for regulating FtsZ assembly. The individual repeats, and their linear organization, are homologous to the spectrin proteins that connect actin filaments to the membrane in eukaryotes, and we thus propose that EzrA is the founding member of the bacterial spectrin family.

  13. Severe bacterial infections in patients with non-transfusion-dependent thalassemia: prevalence and clinical risk factors

    Directory of Open Access Journals (Sweden)

    Nattiya Teawtrakul

    2015-10-01

    Conclusion: The prevalence of bacterial infection in patients with NTDT was found to be moderate. Time after splenectomy >10 years, deferoxamine therapy, and iron overload may be clinical risk factors for severe bacterial infection in patients with NTDT. Bacterial infection should be recognized in splenectomized patients with NTDT, particularly those who have an iron overload.

  14. Severe bacterial infections in patients with non-transfusion-dependent thalassemia: prevalence and clinical risk factors

    OpenAIRE

    Nattiya Teawtrakul; Arunee Jetsrisuparb; Chittima Sirijerachai; Kanchana Chansung; Chinadol Wanitpongpun

    2015-01-01

    Introduction: Bacterial infection is one of the major causes of death in patients with thalassemia. Clinical predictive factors for severe bacterial infection were evaluated in patients with non-transfusion-dependent thalassemia (NTDT). Methods: A retrospective study was conducted of patients with NTDT aged ≥10 years at Srinagarind Hospital, Khon Kaen University, Thailand. Clinical characteristics and potential clinical risk factors for bacterial infection were collected. Risk factors for ...

  15. Hydrological pulse regulating the bacterial heterotrophic metabolism between Amazonian mainstems and floodplain lakes

    Science.gov (United States)

    Vidal, Luciana O.; Abril, Gwenäel; Artigas, Luiz F.; Melo, Michaela L.; Bernardes, Marcelo C.; Lobão, Lúcia M.; Reis, Mariana C.; Moreira-Turcq, Patrícia; Benedetti, Marc; Tornisielo, Valdemar L.; Roland, Fabio

    2015-01-01

    We evaluated in situ rates of bacterial carbon processing in Amazonian floodplain lakes and mainstems, during both high water (HW) and low water (LW) phases (p < 0.05). Our results showed that bacterial production (BP) was lower and more variable than bacterial respiration, determined as total respiration. Bacterial carbon demand was mostly accounted by BR and presented the same pattern that BR in both water phases. Bacterial growth efficiency (BGE) showed a wide range (0.2–23%) and low mean value of 3 and 6%, (in HW and LW, respectively) suggesting that dissolved organic carbon was mostly allocated to catabolic metabolism. However, BGE was regulated by BP in LW phase. Consequently, changes in BGE showed the same pattern that BP. In addition, the hydrological pulse effects on mainstems and floodplains lakes connectivity were found for BP and BGE in LW. Multiple correlation analyses revealed that indexes of organic matter (OM) quality (chlorophyll-a, N stable isotopes and C/N ratios) were the strongest seasonal drivers of bacterial carbon metabolism. Our work indicated that: (i) the bacterial metabolism was mostly driven by respiration in Amazonian aquatic ecosystems resulting in low BGE in either high or LW phase; (ii) the hydrological pulse regulated the bacterial heterotrophic metabolism between Amazonian mainstems and floodplain lakes mostly driven by OM quality. PMID:26483776

  16. Risk factors for community-acquired bacterial meningitis in adults

    NARCIS (Netherlands)

    K.S. Adriani

    2015-01-01

    Bacterial meningitis is an inflammation of the meninges and occurs when bacteria invade the subarachnoid space. The meninges are the protective membranes that surround the brain and the spinal cord. Bacterial meningitis is a life-threatening disease because the proximity of the infection to the brai

  17. Hydrological pulse regulating the bacterial heterotrophic metabolism between Amazonian mainstems and floodplain lakes

    Directory of Open Access Journals (Sweden)

    Luciana Oliveira Vidal

    2015-09-01

    Full Text Available We evaluated in situ rates of bacterial carbon processing in Amazonian floodplain lakes and mainstems, during both high and low water phases (p < 0.05. Our results showed that Bacterial Production (BP was lower and more variable than Bacterial Respiration (BR, determined as total respiration. Bacterial Carbon Demand (BCD was mostly accounted by BR and presented the same pattern that BR in both water phases. Bacterial growth efficiency showed a wide range (0.2–23% and low mean value of 3 and 6 %, (in high and low water respectively suggesting that dissolved organic carbon (DOC was mostly allocated to catabolic metabolism. However, BGE was regulated by BP in low water phase. Consequently, changes in BGE showed the same pattern that BP. In addition, the hydrological pulse effects on mainstems and floodplains lakes connectivity were found for BP and BGE in low water. Multiple correlation analyses revealed that indexes of organic matter quality (chlorophyll-a, N stable isotopes and C/N ratios were the strongest seasonal drivers of bacterial carbon metabolism. Our work indicated that: (1 the bacterial metabolism was mostly driven by respiration in Amazonian aquatic ecosystems resulting in low BGE in either high and low water phase; (2 the hydrological pulse regulated

  18. The dual oxidase gene BdDuox regulates the intestinal bacterial community homeostasis of Bactrocera dorsalis.

    Science.gov (United States)

    Yao, Zhichao; Wang, Ailin; Li, Yushan; Cai, Zhaohui; Lemaitre, Bruno; Zhang, Hongyu

    2016-05-01

    The guts of metazoans are in permanent contact with the microbial realm that includes beneficial symbionts, nonsymbionts, food-borne microbes and life-threatening pathogens. However, little is known concerning how host immunity affects gut bacterial community. Here, we analyze the role of a dual oxidase gene (BdDuox) in regulating the intestinal bacterial community homeostasis of the oriental fruit fly Bactrocera dorsalis. The results showed that knockdown of BdDuox led to an increased bacterial load, and to a decrease in the relative abundance of Enterobacteriaceae and Leuconostocaceae bacterial symbionts in the gut. The resulting dysbiosis, in turn, stimulates an immune response by activating BdDuox and promoting reactive oxygen species (ROS) production that regulates the composition and structure of the gut bacterial community to normal status by repressing the overgrowth of minor pathobionts. Our results suggest that BdDuox plays a pivotal role in regulating the homeostasis of the gut bacterial community in B. dorsalis. PMID:26565723

  19. Regulation of pulmonary and systemic bacterial lipopolysaccharide responses in transgenic mice expressing human elafin.

    Science.gov (United States)

    Sallenave, J-M; Cunningham, G A; James, R M; McLachlan, G; Haslett, C

    2003-07-01

    The control of lung inflammation is of paramount importance in a variety of acute pathologies, such as pneumonia, the acute respiratory distress syndrome, and sepsis. It is becoming increasingly apparent that local innate immune responses in the lung are negatively influenced by systemic inflammation. This is thought to be due to a local deficit in cytokine responses by alveolar macrophages and neutrophils following systemic bacterial infection and the development of a septic response. Recently, using an adenovirus-based strategy which overexpresses the human elastase inhibitor elafin locally in the lung, we showed that elafin is able to prime lung innate immune responses. In this study, we generated a novel transgenic mouse strain expressing human elafin and studied its response to bacterial lipopolysaccharide (LPS) when the LPS was administered locally in the lungs and systemically. When LPS was delivered to the lungs, we found that mice expressing elafin had lower serum-to-bronchoalveolar lavage ratios of proinflammatory cytokines, including tumor necrosis factor alpha (TNF-alpha), macrophage inflammatory protein 2, and monocyte chemoattractant protein 1, than wild-type mice. There was a concomitant increase in inflammatory cell influx, showing that there was potential priming of innate responses in the lungs. When LPS was given systemically, the mice expressing elafin had reduced levels of serum TNF-alpha compared to the levels in wild-type mice. These results indicate that elafin may have a dual function, promoting up-regulation of local lung innate immunity while simultaneously down-regulating potentially unwanted systemic inflammatory responses in the circulation. PMID:12819058

  20. [Progress in expression regulation of bacterial lipase genes--A review].

    Science.gov (United States)

    Zha, Daiming; Yan, Yunjun

    2015-11-01

    Microbial lipases are major sources of commercial ones, which have been extensively used in a wide variety of industrial fields, such as foods, beverages, lipids, detergents, feeds, textiles, leathers, advanced materials, fine chemicals, medicines, cosmetics, papermaking, pollution treatment, and bioenergy. Compared with fungal lipases, bacterial lipases have more types of reactions and exhibit higher activity and better stability in aqueous or organic phases. Amongst bacterial lipases, the most excellent ones are those originating from the genus Pseudomonas. So far, the conventional strategies, such as traditional breeding, optimization of medium and fermentation conditions, cannot fundamentally solve the problem of low production of bacterial lipases. Construction of genetically engineered strains to efficiently overexpress their own lipases is an effective solution. But it must base on clarifying molecular regulation mechanism of lipase gene expression and further finding out key regulators. In this article, we reviewed the progress in expression regulation of bacterial lipase genes from the aspects of direct regulators, quorum sensing system, Gac/Rsm signal transduction system, regulators controlling the Gac/Rsm system, and other regulators. To provide a useful reference for the construction of genetically engineered strains, we also discussed a research prospect in this field based on our ongoing research. PMID:26915218

  1. Dopamine receptor regulating factor, DRRF: A zinc finger transcription factor

    OpenAIRE

    Hwang, Cheol Kyu; D'Souza, Ursula M.; Eisch, Amelia J.; Yajima, Shunsuke; Lammers, Claas-Hinrich; Yang, Young; Lee, Sang-Hyeon; Kim, Yong-Man; Nestler, Eric J.; Mouradian, M. Maral

    2001-01-01

    Dopamine receptor genes are under complex transcription control, determining their unique regional distribution in the brain. We describe here a zinc finger type transcription factor, designated dopamine receptor regulating factor (DRRF), which binds to GC and GT boxes in the D1A and D2 dopamine receptor promoters and effectively displaces Sp1 and Sp3 from these sequences. Consequently, DRRF can modulate the activity of these dopamine receptor promoters. Highest DRRF mRNA levels are found in ...

  2. Bacterial pathogen gene regulation: a DNA-structure-centred view of a protein-dominated domain.

    Science.gov (United States)

    Dorman, Charles J; Colgan, Aoife; Dorman, Matthew J

    2016-07-01

    The mechanisms used by bacterial pathogens to regulate the expression of their genes, especially their virulence genes, have been the subject of intense investigation for several decades. Whole genome sequencing projects, together with more targeted studies, have identified hundreds of DNA-binding proteins that contribute to the patterns of gene expression observed during infection as well as providing important insights into the nature of the gene products whose expression is being controlled by these proteins. Themes that have emerged include the importance of horizontal gene transfer to the evolution of pathogens, the need to impose regulatory discipline upon these imported genes and the important roles played by factors normally associated with the organization of genome architecture as regulatory principles in the control of virulence gene expression. Among these architectural elements is the structure of DNA itself, its variable nature at a topological rather than just at a base-sequence level and its ability to play an active (as well as a passive) part in the gene regulation process. PMID:27252403

  3. The σ enigma: Bacterial σ factors, archaeal TFB and eukaryotic TFIIB are homologs

    OpenAIRE

    Burton, Samuel P; Burton, Zachary F.

    2014-01-01

    Structural comparisons of initiating RNA polymerase complexes and structure-based amino acid sequence alignments of general transcription initiation factors (eukaryotic TFIIB, archaeal TFB and bacterial σ factors) show that these proteins are homologs. TFIIB and TFB each have two-five-helix cyclin-like repeats (CLRs) that include a C-terminal helix-turn-helix (HTH) motif (CLR/HTH domains). Four homologous HTH motifs are present in bacterial σ factors that are relics of CLR/HTH domains. Sequen...

  4. Evolution of bacterial trp operons and their regulation.

    Science.gov (United States)

    Merino, Enrique; Jensen, Roy A; Yanofsky, Charles

    2008-04-01

    Survival and replication of most bacteria require the ability to synthesize the amino acid L-tryptophan whenever it is not available from the environment. In this article we describe the genes, operons, proteins, and reactions involved in tryptophan biosynthesis in bacteria, and the mechanisms they use in regulating tryptophan formation. We show that although the reactions of tryptophan biosynthesis are essentially identical, gene organization varies among species--from whole-pathway operons to completely dispersed genes. We also show that the regulatory mechanisms used for these genes vary greatly. We address the question--what are some potential advantages of the gene organization and regulation variation associated with this conserved, important pathway? PMID:18374625

  5. Evolution of bacterial trp operons and their regulation

    OpenAIRE

    Merino, Enrique; Jensen, Roy A.; Yanofsky, Charles

    2008-01-01

    Survival and replication of most bacteria require the ability to synthesize the amino acid L-tryptophan whenever it is not available from the environment. In this article we describe the genes, operons, proteins, and reactions involved in tryptophan biosynthesis in bacteria, and the mechanisms they use in regulating tryptophan formation. We show that although the reactions of tryptophan biosynthesis are essentially identical, gene organization varies among species - from whole-pathway operons...

  6. Protein Synthesis Initiation Factors: Phosphorylation and Regulation

    Energy Technology Data Exchange (ETDEWEB)

    Karen S. Browning

    2009-06-15

    The initiation of the synthesis of proteins is a fundamental process shared by all living organisms. Each organism has both shared and unique mechanisms for regulation of this vital process. Higher plants provide for a major amount of fixation of carbon from the environment and turn this carbon into food and fuel sources for our use. However, we have very little understanding of how plants regulate the synthesis of the proteins necessary for these metabolic processes. The research carried out during the grant period sought to address some of these unknowns in the regulation of protein synthesis initiation. Our first goal was to determine if phosphorylation plays a significant role in plant initiation of protein synthesis. The role of phosphorylation, although well documented in mammalian protein synthesis regulation, is not well studied in plants. We showed that several of the factors necessary for the initiation of protein synthesis were targets of plant casein kinase and showed differential phosphorylation by the plant specific isoforms of this kinase. In addition, we identified and confirmed the phosphorylation sites in five of the plant initiation factors. Further, we showed that phosphorylation of one of these factors, eIF5, affected the ability of the factor to participate in the initiation process. Our second goal was to develop a method to make initiation factor 3 (eIF3) using recombinant methods. To date, we successfully cloned and expressed 13/13 subunits of wheat eIF3 in E. coli using de novo gene construction methods. The final step in this process is to place the subunits into three different plasmid operons for co-expression. Successful completion of expression of eIF3 will be an invaluable tool to the plant translation community.

  7. Steroidal regulation of uterine resistance to bacterial infection in livestock

    Directory of Open Access Journals (Sweden)

    Lewis Gregory S

    2003-11-01

    Full Text Available Abstract Postpartum uterine infections reduce reproductive efficiency and have significant animal welfare and economic consequences. Postpartum uterine infections are classified as nonspecific, but Arcanobacterium pyogenes and Escherichia coli are usually associated with them in cattle and sheep. Pyometra is the most common type of uterine infection in dairy cattle, and it is detected almost exclusively in cows with active corpora lutea. Luteal progesterone typically down-regulates uterine immune functions and prevents the uterus from resisting infections. Progesterone also can down-regulate uterine eicosanoid synthesis. This seems to be a critical event in the onset of uterine infections, because eicosanoids can up-regulate immune cell functions in vitro. In addition, exogenous prostaglandin F2 alpha stimulates uterine secretion of prostaglandin F2 alpha and enhances immune functions in vivo. Thus, one may hypothesize that eicosanoids can override the negative effects of progesterone and that the up-regulatory effects of exogenous prostaglandin F2 alpha allow the uterus to resolve an infection, regardless of progesterone concentrations. Based on the results of studies to test that hypothesis, cows, sheep, and pigs in various physiological statuses are resistant to intrauterine infusions of Arcanobacterium pyogenes and Escherichia coli, unless progesterone concentrations are increased. In sheep and pigs, exogenous prostaglandin F2 alpha stimulates uterine production of prostaglandin F2 alpha and allows the uterus to resolve Arcanobacterium pyogenes-Escherichia coli-induced infections, even when progesterone is maintained at luteal phase concentrations before and after treatment. Prostaglandin F2 alpha is a proinflammatory molecule that stimulates the production of various proinflammatory cytokines, and it may enhance uterine production of leukotriene B4. Proinflammatory cytokines and leukotriene B4 enhance phagocytosis and lymphocyte functions

  8. Crystal structure analysis reveals Pseudomonas PilY1 as an essential calcium-dependent regulator of bacterial surface motility

    Energy Technology Data Exchange (ETDEWEB)

    Orans, Jillian; Johnson, Michael D.L.; Coggan, Kimberly A.; Sperlazza, Justin R.; Heiniger, Ryan W.; Wolfgang, Matthew C.; Redinbo, Matthew R. (UNC)

    2010-09-21

    Several bacterial pathogens require the 'twitching' motility produced by filamentous type IV pili (T4P) to establish and maintain human infections. Two cytoplasmic ATPases function as an oscillatory motor that powers twitching motility via cycles of pilus extension and retraction. The regulation of this motor, however, has remained a mystery. We present the 2.1 {angstrom} resolution crystal structure of the Pseudomonas aeruginosa pilus-biogenesis factor PilY1, and identify a single site on this protein required for bacterial translocation. The structure reveals a modified {beta}-propeller fold and a distinct EF-hand-like calcium-binding site conserved in pathogens with retractile T4P. We show that preventing calcium binding by PilY1 using either an exogenous calcium chelator or mutation of a single residue disrupts Pseudomonas twitching motility by eliminating surface pili. In contrast, placing a lysine in this site to mimic the charge of a bound calcium interferes with motility in the opposite manner - by producing an abundance of nonfunctional surface pili. Our data indicate that calcium binding and release by the unique loop identified in the PilY1 crystal structure controls the opposing forces of pilus extension and retraction. Thus, PilY1 is an essential, calcium-dependent regulator of bacterial twitching motility.

  9. Oxygen-­dependent regulation of bacterial lipid production

    Energy Technology Data Exchange (ETDEWEB)

    Lemmer, Kimberly C.; Dohnalkova, Alice; Noguera, Daniel R.; Donohue, Timothy J.

    2015-05-12

    Understanding the mechanisms of lipid accumulation in microorganisms is important for several reasons. In addition to providing insight into assembly of biological membranes, lipid accumulation has important applications in the production of renewable fuels and chemicals. The photosynthetic bacterium Rhodobacter sphaeroides is an attractive organism to study lipid accumulation, as it has the somewhat unique ability to increase membrane production at low O₂ tensions. Under these conditions, R. sphaeroides develops invaginations of the cytoplasmic membrane to increase its membrane surface area for housing of the membrane-bound components of its photosynthetic apparatus. Here we use fatty acid levels as a reporter of membrane lipid content. We show that, under low-O₂ and anaerobic conditions, the total fatty acid content per cell increases 3-fold. We also find that the increases in the amount of fatty acid and photosynthetic pigment per cell are correlated as O₂ tensions or light intensity are changed. To ask if lipid and pigment accumulation were genetically separable, we analyzed strains with mutations in known photosynthetic regulatory pathways. While a strain lacking AppA failed to induce photosynthetic pigment-protein complex accumulation, it increased fatty acid content under low O2 conditions. We also found that an intact PrrBA pathway is required for low O2-induced fatty acid accumulation. Our findings suggest a previously unknown role of R. sphaeroides transcriptional regulators in increasing fatty acid and phospholipid accumulation in response to decreased O₂ tension.

  10. Regulating the regulators: modulators of transcription factor activity.

    Science.gov (United States)

    Everett, Logan; Hansen, Matthew; Hannenhalli, Sridhar

    2010-01-01

    Gene transcription is largely regulated by DNA-binding transcription factors (TFs). However, the TF activity itself is modulated via, among other things, post-translational modifications (PTMs) by specific modification enzymes in response to cellular stimuli. TF-PTMs thus serve as "molecular switchboards" that map upstream signaling events to the downstream transcriptional events. An important long-term goal is to obtain a genome-wide map of "regulatory triplets" consisting of a TF, target gene, and a modulator gene that specifically modulates the regulation of the target gene by the TF. A variety of genome-wide data sets can be exploited by computational methods to obtain a rough map of regulatory triplets, which can guide directed experiments. However, a prerequisite to developing such computational tools is a systematic catalog of known instances of regulatory triplets. We first describe PTM-Switchboard, a recent database that stores triplets of genes such that the ability of one gene (the TF) to regulate a target gene is dependent on one or more PTMs catalyzed by a third gene, the modifying enzyme. We also review current computational approaches to infer regulatory triplets from genome-wide data sets and conclude with a discussion of potential future research. PTM-Switchboard is accessible at http://cagr.pcbi.upenn.edu/PTMswitchboard / PMID:20827600

  11. Genetic Identification and Risk Factor Analysis of Asymptomatic Bacterial Colonization on Cardiovascular Implantable Electronic Devices

    Science.gov (United States)

    Chu, Xian-Ming; An, Yi; Li, Xue-Bin; Guo, Ji-Hong

    2014-01-01

    Asymptomatic bacterial colonization of cardiovascular implantable electronic devices (CIEDs) is widespread and increases the risk of clinical CIED infection. The aim of the study was to evaluate the incidence of bacterial colonization of generator pockets in patients without signs of infection and to analyze the relationship with clinical infection and risk factors. From June 2011 to December 2012, 78 patients underwent CIED replacement or upgrade. Exclusion criteria included a clinical diagnosis of CIED infection, bacteremia, or infective endocarditis. All patients were examined for evidence of bacterial 16S rDNA on the device and in the surrounding tissues. Infection cases were recorded during follow-up. The bacterial-positive rate was 38.5% (30 cases); the coagulase-negative Staphylococcus detection rate was the highest (9 cases, 11.5%). Positive bacterial DNA results were obtained from pocket tissue in 23.1% of patients (18 cases), and bacterial DNA was detected on the device in 29.5% of patients (23 cases). During follow-up (median 24.6 months), two patients (6.7%, 2/30) became symptomatic with the same species of microorganism, S. aureus and S. epidermidis. Multivariable logistic regression analysis found that the history of bacterial infection, use of antibiotics, application of antiplatelet drugs, replacement frequency, and renal insufficiency were independent risk factors for asymptomatic bacterial colonization. PMID:25530969

  12. Genetic Identification and Risk Factor Analysis of Asymptomatic Bacterial Colonization on Cardiovascular Implantable Electronic Devices

    Directory of Open Access Journals (Sweden)

    Xian-Ming Chu

    2014-01-01

    Full Text Available Asymptomatic bacterial colonization of cardiovascular implantable electronic devices (CIEDs is widespread and increases the risk of clinical CIED infection. The aim of the study was to evaluate the incidence of bacterial colonization of generator pockets in patients without signs of infection and to analyze the relationship with clinical infection and risk factors. From June 2011 to December 2012, 78 patients underwent CIED replacement or upgrade. Exclusion criteria included a clinical diagnosis of CIED infection, bacteremia, or infective endocarditis. All patients were examined for evidence of bacterial 16S rDNA on the device and in the surrounding tissues. Infection cases were recorded during follow-up. The bacterial-positive rate was 38.5% (30 cases; the coagulase-negative Staphylococcus detection rate was the highest (9 cases, 11.5%. Positive bacterial DNA results were obtained from pocket tissue in 23.1% of patients (18 cases, and bacterial DNA was detected on the device in 29.5% of patients (23 cases. During follow-up (median 24.6 months, two patients (6.7%, 2/30 became symptomatic with the same species of microorganism, S. aureus and S. epidermidis. Multivariable logistic regression analysis found that the history of bacterial infection, use of antibiotics, application of antiplatelet drugs, replacement frequency, and renal insufficiency were independent risk factors for asymptomatic bacterial colonization.

  13. Dopamine receptor regulating factor, DRRF: a zinc finger transcription factor.

    Science.gov (United States)

    Hwang, C K; D'Souza, U M; Eisch, A J; Yajima, S; Lammers, C H; Yang, Y; Lee, S H; Kim, Y M; Nestler, E J; Mouradian, M M

    2001-06-19

    Dopamine receptor genes are under complex transcription control, determining their unique regional distribution in the brain. We describe here a zinc finger type transcription factor, designated dopamine receptor regulating factor (DRRF), which binds to GC and GT boxes in the D1A and D2 dopamine receptor promoters and effectively displaces Sp1 and Sp3 from these sequences. Consequently, DRRF can modulate the activity of these dopamine receptor promoters. Highest DRRF mRNA levels are found in brain with a specific regional distribution including olfactory bulb and tubercle, nucleus accumbens, striatum, hippocampus, amygdala, and frontal cortex. Many of these brain regions also express abundant levels of various dopamine receptors. In vivo, DRRF itself can be regulated by manipulations of dopaminergic transmission. Mice treated with drugs that increase extracellular striatal dopamine levels (cocaine), block dopamine receptors (haloperidol), or destroy dopamine terminals (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine) show significant alterations in DRRF mRNA. The latter observations provide a basis for dopamine receptor regulation after these manipulations. We conclude that DRRF is important for modulating dopaminergic transmission in the brain. PMID:11390978

  14. The role of bacterial antizyme: From an inhibitory protein to AtoC transcriptional regulator

    Directory of Open Access Journals (Sweden)

    Kyriakidis Dimitrios A

    2004-06-01

    Full Text Available Abstract This review considers the role of bacterial antizyme in the regulation of polyamine biosynthesis and gives new perspectives on the involvement of antizyme in other significant cellular mechanisms. Antizyme is a protein molecule induced by the end product of the enzymic reaction that it inhibits, in a non-competitive manner. The bacterial ornithine decarboxylase is regulated by nucleotides, phosphorylation and antizyme. The inhibition of ornithine decarboxylase by antizyme can be relieved to different degrees by DNA or by a variety of synthetic nucleic acid polymers, attributed to a specific interaction between nucleic acid and antizyme. Recently, this interplay between bacterial antizyme and nucleic acid was determined by discerning an additional function to antizyme that proved to be the atoC gene product, encoding the response regulator of the bacterial two-component system AtoS-AtoC. The gene located just upstream of atoC encodes the sensor kinase, named AtoS, that modulates AtoC activity. AtoC regulates expression of atoDAEB operon which is involved in short-chain fatty acid metabolism. Antizyme is thus referred to as AtoC, functioning both as a post-translational and transcriptional regulator. Also, the AtoS-AtoC signal transduction system in E. coli has a positive regulatory role on poly-(R-3-hydroxybutyrate biosynthesis. The properties and gene structural similarities of antizymes from different organisms were compared. It was revealed that conserved domains are present mostly in the C-domain of all antizymes. BLAST analysis of the E. coli antizyme protein (AtoC showed similarities around 69–58% among proteobacteria, g-proteobacteria, enterobacteria and the thermophilic bacterium Thermus thermophilus. A working hypothesis is proposed for the metabolic role of antizyme (AtoC describing the significant biological implications of this protein molecule. Whether antizymes exist to other enzymes in different tissues, meeting the

  15. Nutrient-responsive regulation determines biodiversity in a colicin-mediated bacterial community

    OpenAIRE

    Hol, F.J.H. (Felix); Voges, M.J.; Dekker, C.; Keymer, J.E.

    2014-01-01

    Background Antagonistic interactions mediated by antibiotics are strong drivers of bacterial community dynamics which shape biodiversity. Colicin production by Escherichia coli is such an interaction that governs intraspecific competition and is involved in promoting biodiversity. It is unknown how environmental cues affect regulation of the colicin operon and thus influence antibiotic-mediated community dynamics. Results Here, we investigate the community dynamics of colicin-producing, -sens...

  16. Lipid-linked cell wall precursors regulate membrane association of bacterial actin MreB

    OpenAIRE

    Schirner, Kathrin; Eun, Ye-Jin; Dion, Mike; Luo, Yun; Helmann, John D.; Garner, Ethan C.; Walker, Suzanne

    2014-01-01

    Summary The bacterial actin homolog MreB, which is critical for rod shape determination, forms filaments that rotate around the cell width on the inner surface of the cytoplasmic membrane. What determines filament association with the membranes or with other cell wall elongation proteins is not known. Using specific chemical and genetic perturbations while following MreB filament motion, we find that MreB membrane association is an actively regulated process that depends on the presence of li...

  17. Biotypes and virulence factors of Gardnerella vaginalis isolated from cases of bacterial vaginosis

    OpenAIRE

    J Udayalaxmi; Bhat, G. K.; S Kotigadde

    2011-01-01

    The present study was conducted to correlate the biotypes of Gardnerella vaginalis strains isolated from cases of bacterial vaginosis and their virulence factors. Thirty-two strains of G. vaginalis isolated from cases of bacterial vaginosis were biotyped. Adherence to vaginal epithelial cells, biofilm production, surface hydrophobicity, phospholipase C and protease activity were tested on these isolates. Biotype 1 was the most prevalent (8; 25%), followed by biotype 2 (7; 21.9%) and biotypes ...

  18. Biotypes and virulence factors of Gardnerella vaginalis isolated from cases of bacterial vaginosis

    Directory of Open Access Journals (Sweden)

    J Udayalaxmi

    2011-01-01

    Full Text Available The present study was conducted to correlate the biotypes of Gardnerella vaginalis strains isolated from cases of bacterial vaginosis and their virulence factors. Thirty-two strains of G. vaginalis isolated from cases of bacterial vaginosis were biotyped. Adherence to vaginal epithelial cells, biofilm production, surface hydrophobicity, phospholipase C and protease activity were tested on these isolates. Biotype 1 was the most prevalent (8; 25%, followed by biotype 2 (7; 21.9% and biotypes 5 and 8 (5; 15.6%. We did not find any statistical correlation between G. vaginalis biotypes and its virulence factors. Virulence factors expressed by G. vaginalis were not associated with a single biotype.

  19. Biotypes and virulence factors of Gardnerella vaginalis isolated from cases of bacterial vaginosis.

    Science.gov (United States)

    Udayalaxmi, J; Bhat, G K; Kotigadde, S

    2011-01-01

    The present study was conducted to correlate the biotypes of Gardnerella vaginalis strains isolated from cases of bacterial vaginosis and their virulence factors. Thirty-two strains of G. vaginalis isolated from cases of bacterial vaginosis were biotyped. Adherence to vaginal epithelial cells, biofilm production, surface hydrophobicity, phospholipase C and protease activity were tested on these isolates. Biotype 1 was the most prevalent (8; 25%), followed by biotype 2 (7; 21.9%) and biotypes 5 and 8 (5; 15.6%). We did not find any statistical correlation between G. vaginalis biotypes and its virulence factors. Virulence factors expressed by G. vaginalis were not associated with a single biotype. PMID:21654113

  20. Factors Affecting Bacterial Growth in Drinking Water Distribution System

    Institute of Scientific and Technical Information of China (English)

    WEI LU; XIAO-JIAN ZHANG

    2005-01-01

    Objective To define the influence of some parameters, including assimilable organic carbon (AOC), chloramine residual, etc. on the bacterial growth in drinking water distribution systems. Methods Three typical water treatment plants in a northern city (City T) of China and their corresponding distribution systems were investigated. Some parameters of the water samples, such as heterotrophic plate content (HPC), AOC, CODMn, TOC, and phosphate were measured. Results The AOC in most water samples were more than 100 μg/L, or even more than 200 μg/L in some cases. The HPC in distribution systems increased significantly with the decrease of residual chlorine. When the residual chlorine was less than 0.1 mg/L, the magnitude order of HPC was 104 CFU/mL; when it was 0.5-0.7 mg/L, the HPC was about 500 CFU/mL. Conclusion For controlling the biostability of drinking water, the controlling of AOC and residual chlorine should be considered simultaneously. The influence of phosphors on the AOC tests of water is not significant. Phosphors may not be the limiting nutrient in the water distribution systems.

  1. Systems analysis of multiple regulator perturbations allows discovery of virulence factors in Salmonella

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, Hyunjin; Ansong, Charles; McDermott, Jason E.; Gritsenko, Marina A.; Smith, Richard D.; Heffron, Fred; Adkins, Joshua N.

    2011-06-28

    Background: Systemic bacterial infections are highly regulated and complex processes that are orchestrated by numerous virulence factors. Genes that are coordinately controlled by the set of regulators required for systemic infection are potentially required for pathogenicity. Results: In this study we present a systems biology approach in which sample-matched multi-omic measurements of fourteen virulence-essential regulator mutants were coupled with computational network analysis to efficiently identify Salmonella virulence factors. Immunoblot experiments verified network-predicted virulence factors and a subset was determined to be secreted into the host cytoplasm, suggesting that they are virulence factors directly interacting with host cellular components. Two of these, SrfN and PagK2, were required for full mouse virulence and were shown to be translocated independent of either of the type III secretion systems in Salmonella or the type III injectisome-related flagellar mechanism. Conclusions: Integrating multi-omic datasets from Salmonella mutants lacking virulence regulators not only identified novel virulence factors but also defined a new class of translocated effectors involved in pathogenesis. The success of this strategy at discovery of known and novel virulence factors suggests that the approach may have applicability for other bacterial pathogens.

  2. Regulation of bitter taste responses by tumor necrosis factor.

    Science.gov (United States)

    Feng, Pu; Jyotaki, Masafumi; Kim, Agnes; Chai, Jinghua; Simon, Nirvine; Zhou, Minliang; Bachmanov, Alexander A; Huang, Liquan; Wang, Hong

    2015-10-01

    Inflammatory cytokines are important regulators of metabolism and food intake. Over production of inflammatory cytokines during bacterial and viral infections leads to anorexia and reduced food intake. However, it remains unclear whether any inflammatory cytokines are involved in the regulation of taste reception, the sensory mechanism governing food intake. Previously, we showed that tumor necrosis factor (TNF), a potent proinflammatory cytokine, is preferentially expressed in a subset of taste bud cells. The level of TNF in taste cells can be further induced by inflammatory stimuli. To investigate whether TNF plays a role in regulating taste responses, in this study, we performed taste behavioral tests and gustatory nerve recordings in TNF knockout mice. Behavioral tests showed that TNF-deficient mice are significantly less sensitive to the bitter compound quinine than wild-type mice, while their responses to sweet, umami, salty, and sour compounds are comparable to those of wild-type controls. Furthermore, nerve recording experiments showed that the chorda tympani nerve in TNF knockout mice is much less responsive to bitter compounds than that in wild-type mice. Chorda tympani nerve responses to sweet, umami, salty, and sour compounds are similar between TNF knockout and wild-type mice, consistent with the results from behavioral tests. We further showed that taste bud cells express the two known TNF receptors TNFR1 and TNFR2 and, therefore, are potential targets of TNF. Together, our results suggest that TNF signaling preferentially modulates bitter taste responses. This mechanism may contribute to taste dysfunction, particularly taste distortion, associated with infections and some chronic inflammatory diseases. PMID:25911043

  3. Surface roughness : causal factors : and its relation to bacterial adhesion

    OpenAIRE

    Tellefsen, Georg

    2013-01-01

    Inflammation around teeth and dental implants is considered to be due to microorganisms producing biofilm and thereby initiating the inflammatory reaction. The etiology is not yet fully understood though many risk factors have been identified, e.g. smoking, oral hygiene, stress etc. That surface roughness plays a role both in the development of the biofilm and discoloration of teeth is nowadays beyond doubt. To create a smooth surface is an important part of the oral hygien...

  4. Genes as early responders regulate quorum-sensing and control bacterial cooperation in Pseudomonas aeruginosa.

    Directory of Open Access Journals (Sweden)

    Kelei Zhao

    Full Text Available Quorum-sensing (QS allows bacterial communication to coordinate the production of extracellular products essential for population fitness at higher cell densities. It has been generally accepted that a significant time duration is required to reach appropriate cell density to activate the relevant quiescent genes encoding these costly but beneficial public goods. Which regulatory genes are involved and how these genes control bacterial communication at the early phases are largely un-explored. By determining time-dependent expression of QS-related genes of the opportunistic pathogen Pseudomonas aerugionsa, we show that the induction of social cooperation could be critically influenced by environmental factors to optimize the density of population. In particular, small regulatory RNAs (RsmY and RsmZ serving as early responders, can promote the expression of dependent genes (e.g. lasR to boost the synthesis of intracellular enzymes and coordinate instant cooperative behavior in bacterial cells. These early responders, acting as a rheostat to finely modulate bacterial cooperation, which may be quickly activated under environment threats, but peter off when critical QS dependent genes are fully functional for cooperation. Our findings suggest that RsmY and RsmZ critically control the timing and levels of public goods production, which may have implications in sociomicrobiology and infection control.

  5. A Serine-Threonine Kinase (StkP Regulates Expression of the Pneumococcal Pilus and Modulates Bacterial Adherence to Human Epithelial and Endothelial Cells In Vitro.

    Directory of Open Access Journals (Sweden)

    Jenny A Herbert

    Full Text Available The pneumococcal serine threonine protein kinase (StkP acts as a global regulator in the pneumococcus. Bacterial mutants deficient in StkP are less virulent in animal models of infection. The gene for this regulator is located adjacent to the gene for its cognate phosphatase in the pneumococcal genome. The phosphatase dephosphorylates proteins phosphorylated by StkP and has been shown to regulate a number of key pneumococcal virulence factors and to modulate adherence to eukaryotic cells. The role of StkP in adherence of pneumococci to human cells has not previously been reported. In this study we show StkP represses the pneumococcal pilus, a virulence factor known to be important for bacterial adhesion. In a serotype 4 strain regulation of the pilus by StkP modulates adherence to human brain microvascular endothelial cells (HBMEC and human lung epithelial cells. This suggests that the pneumococcal pilus may play a role in adherence during infections such as meningitis and pneumonia. We show that regulation of the pilus occurs at the population level as StkP alters the number of pili-positive cells within a single culture. As far as we are aware this is the first gene identified outside of the pilus islet that regulates the biphasic expression of the pilus. These findings suggest StkPs role in cell division may be linked to regulation of expression of a cell surface adhesin.

  6. Loss of elongation factor P disrupts bacterial outer membrane integrity

    DEFF Research Database (Denmark)

    Zou, S Betty; Hersch, Steven J; Roy, Hervé;

    2012-01-01

    Elongation factor P (EF-P) is posttranslationally modified at a conserved lysyl residue by the coordinated action of two enzymes, PoxA and YjeK. We have previously established the importance of this modification in Salmonella stress resistance. Here we report that, like poxA and yjeK mutants......, Salmonella strains lacking EF-P display increased susceptibility to hypoosmotic conditions, antibiotics, and detergents and enhanced resistance to the compound S-nitrosoglutathione. The susceptibility phenotypes are largely explained by the enhanced membrane permeability of the efp mutant, which exhibits...... increased uptake of the hydrophobic dye 1-N-phenylnaphthylamine (NPN). Analysis of the membrane proteomes of wild-type and efp mutant Salmonella strains reveals few changes, including the prominent overexpression of a single porin, KdgM, in the efp mutant outer membrane. Removal of KdgM in the efp mutant...

  7. Bacterial sigma factors: a historical, structural, and genomic perspective.

    Science.gov (United States)

    Feklístov, Andrey; Sharon, Brian D; Darst, Seth A; Gross, Carol A

    2014-01-01

    Transcription initiation is the crucial focal point of gene expression in prokaryotes. The key players in this process, sigma factors (σs), associate with the catalytic core RNA polymerase to guide it through the essential steps of initiation: promoter recognition and opening, and synthesis of the first few nucleotides of the transcript. Here we recount the key advances in σ biology, from their discovery 45 years ago to the most recent progress in understanding their structure and function at the atomic level. Recent data provide important structural insights into the mechanisms whereby σs initiate promoter opening. We discuss both the housekeeping σs, which govern transcription of the majority of cellular genes, and the alternative σs, which direct RNA polymerase to specialized operons in response to environmental and physiological cues. The review concludes with a genome-scale view of the extracytoplasmic function σs, the most abundant group of alternative σs. PMID:25002089

  8. The σ enigma: bacterial σ factors, archaeal TFB and eukaryotic TFIIB are homologs.

    Science.gov (United States)

    Burton, Samuel P; Burton, Zachary F

    2014-01-01

    Structural comparisons of initiating RNA polymerase complexes and structure-based amino acid sequence alignments of general transcription initiation factors (eukaryotic TFIIB, archaeal TFB and bacterial σ factors) show that these proteins are homologs. TFIIB and TFB each have two-five-helix cyclin-like repeats (CLRs) that include a C-terminal helix-turn-helix (HTH) motif (CLR/HTH domains). Four homologous HTH motifs are present in bacterial σ factors that are relics of CLR/HTH domains. Sequence similarities clarify models for σ factor and TFB/TFIIB evolution and function and suggest models for promoter evolution. Commitment to alternate modes for transcription initiation appears to be a major driver of the divergence of bacteria and archaea. PMID:25483602

  9. Bacterial elongation factors EF-Tu, their mutants, chimeric forms, and domains: isolation and purification

    Czech Academy of Sciences Publication Activity Database

    Jonák, Jiří

    2007-01-01

    Roč. 849, 1-2 (2007), s. 141-153. ISSN 1570-0232 R&D Projects: GA AV ČR IAA5052206; GA AV ČR KJB500520503; GA MŠk 2B06065 Institutional research plan: CEZ:AV0Z50520514 Keywords : bacterial elongation factors EF-Tu, , G-domain * recombinant EF-Tus * preparation Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 2.935, year: 2007

  10. Use of radioisotopes in studying factors responsible for alfalfa resistance to bacterial wiltxng

    International Nuclear Information System (INIS)

    Studies are summarized dealing with possible causes of vascular dysfunction and resistance of alfalfa to bacterial wilting caused by Corynebacterium insidiosum (McCull.) H.L. Jens from the physiological and biochemical points of view. Using 32P, 35S, 54Mn, 45Ca, 65Zn, and 86Rb the uptake, distribution, translocation, and metabolism of these elements in plants with a different resistance against diseases were investigated. The possible use is discussed of 86Rb as a tracer of potassium. The results suggest that the resistance of alfalfa to bacterial wilting is probably determined by several factors. (author)

  11. Overexpression of the Eggplant (Solanum melongena) NAC Family Transcription Factor SmNAC Suppresses Resistance to Bacterial Wilt.

    Science.gov (United States)

    Na, Chen; Shuanghua, Wu; Jinglong, Fu; Bihao, Cao; Jianjun, Lei; Changming, Chen; Jin, Jiang

    2016-01-01

    Bacterial wilt (BW) is a serious disease that affects eggplant (Solanum melongena) production. Although resistance to this disease has been reported, the underlying mechanism is unknown. In this study, we identified a NAC family transcription factor (SmNAC) from eggplant and characterized its expression, its localization at the tissue and subcellular levels, and its role in BW resistance. To this end, transgenic eggplant lines were generated in which the expression of SmNAC was constitutively up regulated or suppressed using RNAi. The results indicated that overexpression of SmNAC decreases resistance to BW. Moreover, SmNAC overexpression resulted in the reduced accumulation of the plant immune signaling molecule salicylic acid (SA) and reduced expression of ICS1 (a gene that encode isochorismate synthase 1, which is involved in SA biosynthesis). We propose that reduced SA content results in increased bacterial wilt susceptibility in the transgenic lines. Our results provide important new insights into the regulatory mechanisms of bacterial wilt resistance in eggplant. PMID:27528282

  12. Molecular pathogenesis of Helicobacter pylori infection: the role of bacterial virulence factors.

    Science.gov (United States)

    Molnar, Bela; Galamb, Orsolya; Sipos, Ferenc; Leiszter, Katalin; Tulassay, Zsolt

    2010-01-01

    Helicobacter pylori is one of the most common pathogens affecting humankind, infecting approximately 50% of the world's population. Of those infected, many will develop asymptomatic gastritis, but 10% develop gastric or duodenal ulcers. The clinical outcome of the infection may involve a combination of bacterial factors, host factors and environmental factors. In the process of development of gastritis, ulceration and cancer, several cellular and molecular steps follow each other. Infection, acid survival, adhesion, cytotoxicity, epithelial cell turnover changes, inflammation, regeneration or pathological alteration towards erosions, ulceration, and cancer can be observed on the cellular level. Bacterial factors like urease, AmiE, AmiF, hydrogenase and arginase are needed for survival in the acidic gastric environment. The bacterial flagellae are essential to move the bacteria towards the epithelial surface. Adhesive factors like BabA, SabA and ureaseA are necessary for adhesion against MHC-II complexes and Le antigens. The bacteria VacA and CagA are cytotoxic factors. The Cag type IV secretion system delivers these proteins inside the epithelial cells. After disruption of epithelial cell junctions, the bacteria can pass through the gastric wall facing direct immune response from neutrophils, lymphocytes, mast cells and dendritic cells. This review describes and summarizes our present molecular biological information and knowledge about the Helicobacter infective component, cell functions and processes. The possible role of host counter responses and interactions with gastric epithelia and immune cells are also detailed. PMID:21088410

  13. New Kinase Regulation Mechanism Found in HipBA: a Bacterial Persistence Switch

    Energy Technology Data Exchange (ETDEWEB)

    Evdokimov, A.; Voznesensky, I; Fennell, K; Anderson, M; Smith, J; Fisher, D

    2009-01-01

    Bacterial persistence is the ability of individual cells to randomly enter a period of dormancy during which the cells are protected against antibiotics. In Escherichia coli, persistence is regulated by the activity of a protein kinase HipA and its DNA-binding partner HipB, which is a strong inhibitor of both HipA activity and hip operon transcription. The crystal structure of the HipBA complex was solved by application of the SAD technique to a mercury derivative. In this article, the fortuitous and interesting effect of mercury soaks on the native HipBA crystals is discussed as well as the intriguing tryptophan-binding pocket found on the HipA surface. A HipA-regulation model is also proposed that is consistent with the available structural and biochemical data.

  14. New kinase regulation mechanism found in HipBA: a bacterial persistence switch.

    Science.gov (United States)

    Evdokimov, Artem; Voznesensky, Igor; Fennell, Kimberly; Anderson, Marie; Smith, James F; Fisher, Douglas A

    2009-08-01

    Bacterial persistence is the ability of individual cells to randomly enter a period of dormancy during which the cells are protected against antibiotics. In Escherichia coli, persistence is regulated by the activity of a protein kinase HipA and its DNA-binding partner HipB, which is a strong inhibitor of both HipA activity and hip operon transcription. The crystal structure of the HipBA complex was solved by application of the SAD technique to a mercury derivative. In this article, the fortuitous and interesting effect of mercury soaks on the native HipBA crystals is discussed as well as the intriguing tryptophan-binding pocket found on the HipA surface. A HipA-regulation model is also proposed that is consistent with the available structural and biochemical data. PMID:19622872

  15. Spaceflight Alters Bacterial Gene Expression and Virulence and Reveals Role for Global Regulator Hfq

    Science.gov (United States)

    Wilson, J. W.; Ott, C. M.; zuBentrup, K. Honer; Ramamurthy R.; Quick, L.; Porwollik, S.; Cheng, P.; McClellan, M.; Tsaprailis, G.; Radabaugh, T.; Hunt, A.; Fernandez, D.; Richter, E.; Shah, M.; Kilcoyne, M.; Joshi, L.; Nelman-Gonzalez, M.; Hing, S.; Parra, M.; Dumaras, P.; Norwood, K.; Nickerson, C. A.; Bober, R.; Devich, J.; Ruggles, A.

    2007-01-01

    A comprehensive analysis of both the molecular genetic and phenotypic responses of any organism to the spaceflight environment has never been accomplished due to significant technological and logistical hurdles. Moreover, the effects of spaceflight on microbial pathogenicity and associated infectious disease risks have not been studied. The bacterial pathogen Salmonella typhimurium was grown aboard Space Shuttle mission STS-115 and compared to identical ground control cultures. Global microarray and proteomic analyses revealed 167 transcripts and 73 proteins changed expression with the conserved RNA-binding protein Hfq identified as a likely global regulator involved in the response to this environment. Hfq involvement was confirmed with a ground based microgravity culture model. Spaceflight samples exhibited enhanced virulence in a murine infection model and extracellular matrix accumulation consistent with a biofilm. Strategies to target Hfq and related regulators could potentially decrease infectious disease risks during spaceflight missions and provide novel therapeutic options on Earth.

  16. Differential regulation of horizontally acquired and core genome genes by the bacterial modulator H-NS.

    Directory of Open Access Journals (Sweden)

    Rosa C Baños

    2009-06-01

    Full Text Available Horizontal acquisition of DNA by bacteria dramatically increases genetic diversity and hence successful bacterial colonization of several niches, including the human host. A relevant issue is how this newly acquired DNA interacts and integrates in the regulatory networks of the bacterial cell. The global modulator H-NS targets both core genome and HGT genes and silences gene expression in response to external stimuli such as osmolarity and temperature. Here we provide evidence that H-NS discriminates and differentially modulates core and HGT DNA. As an example of this, plasmid R27-encoded H-NS protein has evolved to selectively silence HGT genes and does not interfere with core genome regulation. In turn, differential regulation of both gene lineages by resident chromosomal H-NS requires a helper protein: the Hha protein. Tight silencing of HGT DNA is accomplished by H-NS-Hha complexes. In contrast, core genes are modulated by H-NS homoligomers. Remarkably, the presence of Hha-like proteins is restricted to the Enterobacteriaceae. In addition, conjugative plasmids encoding H-NS variants have hitherto been isolated only from members of the family. Thus, the H-NS system in enteric bacteria presents unique evolutionary features. The capacity to selectively discriminate between core and HGT DNA may help to maintain horizontally transmitted DNA in silent form and may give these bacteria a competitive advantage in adapting to new environments, including host colonization.

  17. Rosmarinic acid is a homoserine lactone mimic produced by plants that activates a bacterial quorum-sensing regulator.

    Science.gov (United States)

    Corral-Lugo, Andrés; Daddaoua, Abdelali; Ortega, Alvaro; Espinosa-Urgel, Manuel; Krell, Tino

    2016-01-01

    Quorum sensing is a bacterial communication mechanism that controls genes, enabling bacteria to live as communities, such as biofilms. Homoserine lactone (HSL) molecules function as quorum-sensing signals for Gram-negative bacteria. Plants also produce previously unidentified compounds that affect quorum sensing. We identified rosmarinic acid as a plant-derived compound that functioned as an HSL mimic. In vitro assays showed that rosmarinic acid bound to the quorum-sensing regulator RhlR of Pseudomonas aeruginosa PAO1 and competed with the bacterial ligand N-butanoyl-homoserine lactone (C4-HSL). Furthermore, rosmarinic acid stimulated a greater increase in RhlR-mediated transcription in vitro than that of C4-HSL. In P. aeruginosa, rosmarinic acid induced quorum sensing-dependent gene expression and increased biofilm formation and the production of the virulence factors pyocyanin and elastase. Because P. aeruginosa PAO1 infection induces rosmarinic acid secretion from plant roots, our results indicate that rosmarinic acid secretion is a plant defense mechanism to stimulate a premature quorum-sensing response. P. aeruginosa is a ubiquitous pathogen that infects plants and animals; therefore, identification of rosmarinic acid as an inducer of premature quorum-sensing responses may be useful in agriculture and inform human therapeutic strategies. PMID:26732761

  18. Deleted in Malignant Brain Tumors 1 is up-regulated in bacterial endocarditis and binds to components of vegetations

    DEFF Research Database (Denmark)

    Müller, Hanna; Renner, Marcus; Helmke, Burkhard M;

    2009-01-01

    OBJECTIVE: Bacterial endocarditis is a frequent infectious cardiac disease, especially in patients with congenital or acquired heart defects. It is characterized by bacterial colonization of the heart valves and the appearance of vegetations consisting of fibrin, blood cells, and bacteria. The...... glycoprotein Deleted in Malignant Brain Tumors 1 is a scavenger receptor cysteine-rich protein with functions in innate immunity and epithelial differentiation. Because of the aggregating capacity of Deleted in Malignant Brain Tumors 1, we hypothesized that an up-regulation in bacterial endocarditis may be...... linked to the development of vegetations. METHODS: Heart tissue of 19 patients with bacterial endocarditis and 10 controls without bacterial endocarditis was analyzed by immunohistochemistry. The effect of human recombinant Deleted in Malignant Brain Tumors 1 on erythrocyte aggregation was measured using...

  19. EFFECTS OF PSYCHOTROPIC DRUGS AS BACTERIAL EFFLUX PUMP INHIBITORS ON QUORUM SENSING REGULATED BEHAVIORS

    Directory of Open Access Journals (Sweden)

    Aynur Aybey

    2014-10-01

    Full Text Available Psychotropic drugs are known to have antimicrobial activity against several groups of microorganisms. The antidepressant agents such as duloxetine, paroxetine, hydroxyzine and venlafaxine are shown to act as efflux pump inhibitors in bacterial cells. In order to the investigation of the effects of psychotropic drugs were determined for clinically significant pathogens by using standart broth microdillusion method. The anti-quorum sensing (anti-QS activity of psychotropic drugs was tested against four test pathogens using the agar well diffusion method. All drugs showed strong inhibitory effect on the growth of S. typhimurium. Additionally, quorum sensing-regulated behaviors of Pseudomonas aeruginosa, including swarming, swimming and twitching motility and alkaline protease production were investigated. Most effective drugs on swarming, swimming and twitching motility and alkaline protease production, respectively, were paroxetine and duloxetine; duloxetine; hydroxyzine and venlafaxine; paroxetine and venlafaxine; venlafaxine. Accordingly, psychotropic drugs were shown strongly anti-QS activity by acting as bacterial efflux pump inhibitors and effection on motility and alkaline protease production of P. aeruginosa.

  20. Anaerobes and Bacterial Vaginosis in Pregnancy: Virulence Factors Contributing to Vaginal Colonisation

    OpenAIRE

    Africa, Charlene W.J.; Janske Nel; Megan Stemmet

    2014-01-01

    The aetiology and pathogenesis of bacterial vaginosis (BV) is unclear but it appears to be associated with factors that disrupt the normal acidity of the vagina thus altering the equilibrium between the normal vaginal microbiota. BV has serious implications for female morbidity, including reports of pelvic inflammatory disease, adverse pregnancy outcomes, increased susceptibility to sexually transmitted infections and infertility. This paper reviewed new available information regarding poss...

  1. Classroom Activities to Engage Students and Promote Critical Thinking about Genetic Regulation of Bacterial Quorum Sensing

    Directory of Open Access Journals (Sweden)

    Kimberly Aebli

    2016-05-01

    Full Text Available We developed an interactive activity to mimic bacterial quorum sensing, and a classroom worksheet to promote critical thinking about genetic regulation of the lux operon. The interactive quorum sensing activity engages students and provides a direct visualization of how population density functions to influence light production in bacteria. The worksheet activity consists of practice problems that require students to apply basic knowledge of the lux operon in order to make predictions about genetic complementation experiments, and students must evaluate how genetic mutations in the lux operon affect gene expression and overall phenotype. The worksheet promotes critical thinking and problem solving skills, and emphasizes the roles of diffusible signaling molecules, regulatory proteins, and structural proteins in quorum sensing.

  2. Factors shaping bacterial phylogenetic and functional diversity in coastal waters of the NW Mediterranean Sea

    Science.gov (United States)

    Boras, Julia A.; Vaqué, Dolors; Maynou, Francesc; Sà, Elisabet L.; Weinbauer, Markus G.; Sala, Maria Montserrat

    2015-03-01

    To evaluate the main factors shaping bacterioplankton phylogenetic and functional diversity in marine coastal waters, we carried out a two-year study based on a monthly sampling in Blanes Bay (NW Mediterranean). We expected the key factors driving bacterial diversity to be (1) temperature and nutrient concentration, together with chlorophyll a concentration as an indicator of phytoplankton biomass and, hence, a carbon source for bacteria (here called bottom-up factors), and (2) top-down pressure (virus- and protist-mediated mortality of bacteria). Phylogenetic diversity was analyzed by denaturing gradient gel electrophoresis (DGGE) of 16S rRNA. Functional diversity was assessed by using monomeric carbon sources in Biolog EcoPlates and by determining the activity of six extracellular enzymes. Our results indicate that the bacterial phylogenetic and functional diversity in this coastal system is shaped mainly by bottom-up factors. A dendrogram analysis of the DGGE banding patterns revealed three main sample clusters. Two clusters differed significantly in temperature, nitrate and chlorophyll a concentration, and the third was characterized by the highest losses of bacterial production due to viral lysis detected over the whole study period. Protistan grazing had no effect on bacterial functional diversity, since there were no correlations between protist-mediated mortality (PMM) and extracellular enzyme activities, and utilization of only two out of the 31 carbon sources (N-acetyl-D-glucosamine and α-cyclodextrin) was correlated with PMM. In contrast, virus-mediated mortality correlated with changes in the percentage of use of four carbon sources, and also with specific leu-aminopeptidase and β-glucosidase activity. This suggests that viral lysate provides a pool of labile carbon sources, presumably including amino acids and glucose, which may inhibit proteolytic and glucosidic activity. Our results indicate that bottom-up factors play a more important role than

  3. Setting the X Factor in Price Cap Regulation Plans

    OpenAIRE

    Jeffrey I. Bernstein; Sappington, David E.M.

    1998-01-01

    Despite the popularity of price cap regulation in practice, the economic literature provides relatively little guidance on how to determine the X factor, which is the rate at which inflation -adjusted output prices must fall under price cap plans. We review the standard principles that inform the choice of the X factor, and then consider important extensions. We analyze appropriate modifications of the X factor: (1) when only a subset of the firm's products are subject to price cap regulation...

  4. Proteomic analysis of growth phase-dependent expression of Legionella pneumophila proteins which involves regulation of bacterial virulence traits.

    Directory of Open Access Journals (Sweden)

    Tsuyoshi Hayashi

    Full Text Available Legionella pneumophila, which is a causative pathogen of Legionnaires' disease, expresses its virulent traits in response to growth conditions. In particular, it is known to become virulent at a post-exponential phase in vitro culture. In this study, we performed a proteomic analysis of differences in expression between the exponential phase and post-exponential phase to identify candidates associated with L. pneumophila virulence using 2-Dimentional Fluorescence Difference Gel Electrophoresis (2D-DIGE combined with Matrix-Assisted Laser Desorption/Ionization-Mass Spectrometry (MALDI-TOF-MS. Of 68 identified proteins that significantly differed in expression between the two growth phases, 64 were up-regulated at a post-exponential phase. The up-regulated proteins included enzymes related to glycolysis, ketone body biogenesis and poly-3-hydroxybutyrate (PHB biogenesis, suggesting that L. pneumophila may utilize sugars and lipids as energy sources, when amino acids become scarce. Proteins related to motility (flagella components and twitching motility-associated proteins were also up-regulated, predicting that they enhance infectivity of the bacteria in host cells under certain conditions. Furthermore, 9 up-regulated proteins of unknown function were found. Two of them were identified as novel bacterial factors associated with hemolysis of sheep red blood cells (SRBCs. Another 2 were found to be translocated into macrophages via the Icm/Dot type IV secretion apparatus as effector candidates in a reporter assay with Bordetella pertussis adenylate cyclase. The study will be helpful for virulent analysis of L. pneumophila from the viewpoint of physiological or metabolic modulation dependent on growth phase.

  5. Orthologous transcription factors in bacteria have different functions and regulate different genes.

    Directory of Open Access Journals (Sweden)

    Morgan N Price

    2007-09-01

    Full Text Available Transcription factors (TFs form large paralogous gene families and have complex evolutionary histories. Here, we ask whether putative orthologs of TFs, from bidirectional best BLAST hits (BBHs, are evolutionary orthologs with conserved functions. We show that BBHs of TFs from distantly related bacteria are usually not evolutionary orthologs. Furthermore, the false orthologs usually respond to different signals and regulate distinct pathways, while the few BBHs that are evolutionary orthologs do have conserved functions. To test the conservation of regulatory interactions, we analyze expression patterns. We find that regulatory relationships between TFs and their regulated genes are usually not conserved for BBHs in Escherichia coli K12 and Bacillus subtilis. Even in the much more closely related bacteria Vibrio cholerae and Shewanella oneidensis MR-1, predicting regulation from E. coli BBHs has high error rates. Using gene-regulon correlations, we identify genes whose expression pattern differs between E. coli and S. oneidensis. Using literature searches and sequence analysis, we show that these changes in expression patterns reflect changes in gene regulation, even for evolutionary orthologs. We conclude that the evolution of bacterial regulation should be analyzed with phylogenetic trees, rather than BBHs, and that bacterial regulatory networks evolve more rapidly than previously thought.

  6. Analysis on the risk factors of bacterial meningitis complicated with subdural effusion

    Directory of Open Access Journals (Sweden)

    Zhi JIANG

    2015-08-01

    Full Text Available Objective To investigate the risk factors of bacterial meningitis complicated with subdural effusion.  Methods The clinical data of children with bacterial meningitis in our hospital were collected and analyzed retrospectively. Logistic regression analysis was used to investigate the risk factors for subdural effusion.  Results A total of 128 cases were divided into control group (N = 64 and subdural effusion group (N = 64. There was no significant difference on serum erythrocyte sedimentation rate (ESR, C-reactive protein (CRP, and white blood cell (WBC between 2 groups (P > 0.05, for all. Compared with control group, cerebrospinal fluid (CSF WBC (Z = 3.126, P = 0.003, CSF protein (Z = 4.928, P = 0.000 and serum procalcitonin (PCT; Z = 2.823, P = 0.007 in subdural effusion group were significantly higher, while CSF glucose (t = 2.166, P = 0.033 was significantly lower. After treatment, CSF WBC (Z = 2.467, P = 0.012 in subdural effusion group was still significantly higher than that of control group, and CSF glucose (t = 4.938, P = 0.000 was still significantly lower. Logistic regression analysis showed that WBC in CSF (P = 0.027, CSF protein (P = 0.002 and serum PCT (P = 0.014 were independent risk factors for bacterial meningitis complicated with subdural effusion.  Conclusions CSF examination of children with bacterial meningitis reveals significant increase of CSF WBC, CSF protein and serum PCT, suggesting concurrent subdural effusion is easily occurred. DOI: 10.3969/j.issn.1672-6731.2015.08.012

  7. Bacterial and fungal endophthalmitis in Upper Egypt:related species and risk factors

    Institute of Scientific and Technical Information of China (English)

    AA Gharamah; AM Moharram; MA Ismail; AK AL-Hussaini

    2012-01-01

    Objective: To study risk factors, contributing factors of bacterial and fungal endophthalmitis in Upper Egypt, test the isolated species sensitive to some therapeutic agents, and to investigate the air-borne bacteria and fungi in opthalmology operating rooms. Methods: Thirty one cases of endophthalmitis were clinically diagnosed and microbiologically studied. Indoor air-borne bacteria and fungi inside four air-conditioned operating rooms in the Ophthalmology Department at Assiut University Hospitals were also investigated. The isolated microbes from endophthalmitis cases were tested for their ability to produce some extracellular enzymes including protease, lipase, urease, phosphatase and catalase. Also the ability of 5 fungal isolates from endophthalmitis origin to produce mycotoxins and their sensitivity to some therapeutic agents were studied. Results: Results showed that bacteria and fungi were responsihle for infection in 10 and 6 cases of endophthalmitis, respectively and only 2 cases produced a mixture of bacteria and fungi. Trauma was the most prevalent risk factor of endophthalmitis where 58.1% of the 31 cases were due to trauma. In ophthalmology operating rooms, different bacterial and fungal species were isolated. 8 bacterial and 5 fungal isolates showed their ability to produce enzymes while only 3 fungal isolates were able to produce mycotoxins. Terbinafine showed the highest effect against most isolates in vitro. Conclusions: The ability of bacterial and fungal isolates to produce extracellular enzymes and mycotoxins may be aid in the invasion and destruction of eye tissues. Microbial contamination of operating rooms with air-borne bacteria and fungi in the present work may be a source of postoperative endophthalmitis.

  8. Bacterial cytolysin during meningitis disrupts the regulation of glutamate in the brain, leading to synaptic damage.

    Directory of Open Access Journals (Sweden)

    Carolin Wippel

    Full Text Available Streptococcus pneumoniae (pneumococcal meningitis is a common bacterial infection of the brain. The cholesterol-dependent cytolysin pneumolysin represents a key factor, determining the neuropathogenic potential of the pneumococci. Here, we demonstrate selective synaptic loss within the superficial layers of the frontal neocortex of post-mortem brain samples from individuals with pneumococcal meningitis. A similar effect was observed in mice with pneumococcal meningitis only when the bacteria expressed the pore-forming cholesterol-dependent cytolysin pneumolysin. Exposure of acute mouse brain slices to only pore-competent pneumolysin at disease-relevant, non-lytic concentrations caused permanent dendritic swelling, dendritic spine elimination and synaptic loss. The NMDA glutamate receptor antagonists MK801 and D-AP5 reduced this pathology. Pneumolysin increased glutamate levels within the mouse brain slices. In mouse astrocytes, pneumolysin initiated the release of glutamate in a calcium-dependent manner. We propose that pneumolysin plays a significant synapto- and dendritotoxic role in pneumococcal meningitis by initiating glutamate release from astrocytes, leading to subsequent glutamate-dependent synaptic damage. We outline for the first time the occurrence of synaptic pathology in pneumococcal meningitis and demonstrate that a bacterial cytolysin can dysregulate the control of glutamate in the brain, inducing excitotoxic damage.

  9. Hormonal Factors of Anti-Mutagenesis Regulation

    OpenAIRE

    RZA, Mekhtizadeh Emin

    2009-01-01

    The genetic activity of phytohormones (Phs) was studied. The investigation was conducted with 4 plants (Allium fistulosum, Lycopersicon esculentum, Triticum aestivum, and Gossypium hirsutum). The action of Phs on plant genetic processes was evaluated by chromosome aberration testing. It was observed that the exogenic Phs exerted a stabilizing effect on spontaneous plant mutagenesis. The use of Phs before and after the action of mutagenic factors contributed to an increase in the anti-mutation...

  10. [Regulation factors of stomach emptying in dogs].

    Science.gov (United States)

    Krejs, G J; Hegglin, J; Säuberli, H; Largiadér, F; Schmid, P; Blum, A L

    1976-03-01

    Gastric emptying of organic acids was studied in 6 healthy mongrel dogs. After chronic esophagostomies were performed according to the method of Komarov, a total of 340 test meals were instilled. Each test meal consisted of 300 ml of 6 different organic acids with decreasing molecular weight and different concentrations. After the experiments were achieved, each dog underwent a proximal gastric vagotomy according to the method of Amdrup, and experiments with citric acid were repeated. The results may be summarized as follows: multiple stepwise regression analysis of the data is consistent with a model in which gastric emptying of organic acids is regulated by 3 receptors. The receptors respond to concentration of the organic acid, the actual volume, and the type of acid. The volume receptor is located in the corpus of the stomach because the effect of volume accelerates the emptying rate after proximal gastric vagotomy while the effects of concentration and type of acid remain unchanged. PMID:1270294

  11. Correlation models between environmental factors and bacterial resistance to antimony and copper.

    Directory of Open Access Journals (Sweden)

    Zunji Shi

    Full Text Available Antimony (Sb and copper (Cu are toxic heavy metals that are associated with a wide variety of minerals. Sb(III-oxidizing bacteria that convert the toxic Sb(III to the less toxic Sb(V are potentially useful for environmental Sb bioremediation. A total of 125 culturable Sb(III/Cu(II-resistant bacteria from 11 different types of mining soils were isolated. Four strains identified as Arthrobacter, Acinetobacter and Janibacter exhibited notably high minimum inhibitory concentrations (MICs for Sb(III (>10 mM,making them the most highly Sb(III-resistant bacteria to date. Thirty-six strains were able to oxidize Sb(III, including Pseudomonas-, Comamonas-, Acinetobacter-, Sphingopyxis-, Paracoccus- Aminobacter-, Arthrobacter-, Bacillus-, Janibacter- and Variovorax-like isolates. Canonical correspondence analysis (CCA revealed that the soil concentrations of Sb and Cu were the most obvious environmental factors affecting the culturable bacterial population structures. Stepwise linear regression was used to create two predictive models for the correlation between soil characteristics and the bacterial Sb(III or Cu(II resistance. The concentrations of Sb and Cu in the soil was the significant factors affecting the bacterial Sb(III resistance, whereas the concentrations of S and P in the soil greatly affected the bacterial Cu(II resistance. The two stepwise linear regression models that we derived are as follows: MIC(Sb(III=606.605+0.14533 x C(Sb+0.4128 x C(Cu and MIC((Cu(II=58.3844+0.02119 x C(S+0.00199 x CP [where the MIC(Sb(III and MIC(Cu(II represent the average bacterial MIC for the metal of each soil (μM, and the C(Sb, C(Cu, C(S and C(P represent concentrations for Sb, Cu, S and P (mg/kg in soil, respectively, p<0.01]. The stepwise linear regression models we developed suggest that metals as well as other soil physicochemical parameters can contribute to bacterial resistance to metals.

  12. Bacterial cell-cell communication in the host via RRNPP peptide-binding regulators

    Directory of Open Access Journals (Sweden)

    David ePerez-Pascual

    2016-05-01

    Full Text Available Human microbiomes are composed of complex and dense bacterial consortia. In these environments, bacteria are able to react quickly to change by coordinating their gene expression at the population level via small signaling molecules. In Gram-positive bacteria, cell-cell communication is mostly mediated by peptides that are released into the extracellular environment. Cell-cell communication based on these peptides is especially widespread in the group Firmicutes, in which they regulate a wide array of biological processes, including functions related to host-microbe interactions. Among the different agents of communication, the RRNPP family of cytoplasmic transcriptional regulators, together with their cognate re-internalized signaling peptides, represents a group of emerging importance. RRNPP members that have been studied so far are found mainly in species of bacilli, streptococci, and enterococci. These bacteria are characterized as both human commensal and pathogenic, and share different niches in the human body with other microorganisms. The goal of this mini-review is to present the current state of research on the biological relevance of RRNPP mechanisms in the context of the host, highlighting their specific roles in commensalism or virulence.

  13. [The bacterial microflora of diabetic foot infection and factors determining its spectrum in Ouagadougou (Burkina Faso)].

    Science.gov (United States)

    Guira, O; Tiéno, H; Traoré, S; Diallo, I; Ouangré, E; Sagna, Y; Zabsonré, J; Yanogo, D; Traoré, S S; Drabo, Y J

    2015-12-01

    The aim of the study was to describe the bacterial microflora of diabetic foot infection and to identify the factors which determine the bacterial spectrum in order to increase empiric antibiotic prescription in Ouagadougou. The study was a cross-sectional one, carried from July 1st, 2011 to June 30, 2012 in the departments of internal medicine and general and digestive surgery in Yalgado Ouédraogo teaching hospital. Samples for bacteriological tests consisted of aspiration of pus through the healthy skin, curettage and swab of the base of the ulceration or tissue biopsy from foot lesions. The bacteria's sensitivity to antibiotics has been tested by the qualitative method (Kirby-Bauer). The frequency of diabetic foot infection was 14.45% and the monthly incidence 5.33. The mean age of patients was 56 years and the sex ratio 1.37. Foot ulcerations were chronic in 33 (51.56%), necrotic in 51 (79.69%) and associated with osteitis in 40 (62.5%) patients. Infection was grade 3 in 70.3% cases. Thirty-nine patients had received antibiotics before hospital admission. Among the 71 samples, 62 (87.32%) cultures were positive: 53 (85.48%) monomicrobial and 9 (14.52%) bimicrobial. Aerobic Gram-positive cocci (76%) were the most frequent from ulcerations: Staphylococcus aureus (32.39%), Streptococcus sp (18.30%). Negative coagulase staphylococci have been found in 23.94% cases. Aerobic gram-negative bacilli have been isolated from 24% ulcerations. No factor was associated with the type of bacteria. Gram-positive pathogen cocci showed a high sensitivity to amoxicillin-clavulanic acid and oxacillin. No methicillin-resistant Staphylococcus aureus (MRSA) or extended-spectrum beta lactamase Enterobacteriaceae (ESBL) have been isolated. A better design is necessary to a clarification of bacterial flora in diabetic foot infections. Prevention of bacterial resistance is also needed. PMID:26187771

  14. Characterizing the interplay betwen mulitple levels of organization within bacterial sigma factor regulatory networks

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Qiu [University of California, San Diego; Nagarajan, Harish [University of California, San Diego; Embree, Mallory [University of California, San Diego; Shieu, Wendy [University of California, San Diego; Abate, Elisa [University of California, San Diego; Juarez, Katy [Universidad Nacional Autonoma de Mexico (UNAM); Cho, Byung-Kwan [University of California, San Diego; Elkins, James G [ORNL; Nevin, Kelly P. [University of Massachusetts, Amherst; Barrett, Christian [University of California, San Diego; Lovley, Derek [University of Massachusetts, Amherst; Palsson, Bernhard O. [University of California, San Diego; Zengler, Karsten [University of California, San Diego

    2013-01-01

    Bacteria contain multiple sigma factors, each targeting diverse, but often overlapping sets of promoters, thereby forming a complex network. The layout and deployment of such a sigma factor network directly impacts global transcriptional regulation and ultimately dictates the phenotype. Here we integrate multi-omic data sets to determine the topology, the operational, and functional states of the sigma factor network in Geobacter sulfurreducens, revealing a unique network topology of interacting sigma factors. Analysis of the operational state of the sigma factor network shows a highly modular structure with sN being the major regulator of energy metabolism. Surprisingly, the functional state of the network during the two most divergent growth conditions is nearly static, with sigma factor binding profiles almost invariant to environmental stimuli. This first comprehensive elucidation of the interplay between different levels of the sigma factor network organization is fundamental to characterize transcriptional regulatory mechanisms in bacteria.

  15. Dual 4- and 5-phosphatase activities regulate SopB-dependent phosphoinositide dynamics to promote bacterial entry.

    Science.gov (United States)

    Piscatelli, Heather L; Li, Menghan; Zhou, Daoguo

    2016-05-01

    Salmonella are able to invade non-phagocytic cells such as intestinal epithelial cells by modulating the host actin cytoskeleton to produce membrane ruffles. Two type III effector proteins SopB and SopE play key roles to this modulation. SopE is a known guanine nucleotide exchange factor (GEF) capable of activating Rac1 and CDC42. SopB is a phosphatidylinositol 4-phosphatase and 5-phosphatase promoting membrane ruffles and invasion of Salmonella through undefined mechanisms. Previous studies have demonstrated that the 4-phosphatase activity of SopB is required for PtdIns-3-phosphate (PtdIns(3)P) accumulation and SopB-mediated invasion. We show here that both the 4-phosphatase as well as the 5-phosphatase activities of SopB are essential in ruffle formation and subsequent invasion. We found that the 5-phosphatase activity of SopB is likely responsible for generating PtdIns-3,4-bisphosphate (PtdIns(3,4)P2 ) and subsequent recruitment of sorting nexin 9 (SNX9), an actin modulating protein. Intriguingly, the 4-phosphatase activity is responsible for the dephosphorylation of PtdIns(3,4)P2 into PtdIns(3)P. Alone, neither activity is sufficient for ruffling but when acting in conjunction with one another, the 4-phosphatase and 5-phosphatase activities led to SNX9-mediated ruffling and Salmonella invasion. This work reveals the unique ability of bacterial effector protein SopB to utilize both its 4- and 5-phosphatase activities to regulate phosphoinositide dynamics to promote bacterial entry. PMID:26537021

  16. Spatiotemporal regulation of Rap guanine nucleotide exchange factors

    OpenAIRE

    Consonni, S.V.

    2014-01-01

    Guanine nucleotide exchange factors (GEFs) and GTPase activating proteins (GAPs) orchestrate the activity of small G-proteins. In response to extracellular stimuli, GEFs and GAPs activate signaling cascades regulated by G-proteins by controlling their regulation in time and in space. Generally, GEFs function as activators of G-proteins by promoting their GTP-bound state while GAPs serve as inhibitors by increasing the rate of GTP hydrolysis. Our understanding of the mechanisms of regulation o...

  17. Spatiotemporal regulation of Rap guanine nucleotide exchange factors

    NARCIS (Netherlands)

    Consonni, S.V.

    2014-01-01

    Guanine nucleotide exchange factors (GEFs) and GTPase activating proteins (GAPs) orchestrate the activity of small G-proteins. In response to extracellular stimuli, GEFs and GAPs activate signaling cascades regulated by G-proteins by controlling their regulation in time and in space. Generally, GEFs

  18. Vitamin D Receptor Negatively Regulates Bacterial-Stimulated NF-κB Activity in Intestine

    OpenAIRE

    Wu, Shaoping; Liao, Anne P.; Xia, Yinglin; Li, Yan Chun; Li, Jian-Dong; Sartor, R. Balfour; Sun, Jun

    2010-01-01

    Vitamin D receptor (VDR) plays an essential role in gastrointestinal inflammation. Most investigations have focused on the immune response; however, how bacteria regulate VDR and how VDR modulates the nuclear factor (NF)-κB pathway in intestinal epithelial cells remain unexplored. This study investigated the effects of VDR ablation on NF-κB activation in intestinal epithelia and the role of enteric bacteria on VDR expression. We found that VDR−/− mice exhibited a pro-inflammatory bias. After ...

  19. Elongation factor P mediates a novel post-transcriptional regulatory pathway critical for bacterial virulence

    DEFF Research Database (Denmark)

    Zou, S Betty; Roy, Hervé; Ibba, Michael;

    2012-01-01

    Bacterial pathogens detect and integrate multiple environmental signals to coordinate appropriate changes in gene expression including the selective expression of virulence factors, changes to metabolism and the activation of stress response systems. Mutations that abolish the ability of the...... lysine residue in the translation factor elongation factor P (EF-P). Strains in which EF-P is unmodified due to the absence of PoxA or YjeK are attenuated for virulence and display highly pleiotropic phenotypes, including hypersusceptibility to a wide range of unrelated antimicrobial compounds. Work from...... pathogen to respond to external cues are typically attenuating. Here we discuss our recent discovery of a novel post-transcriptional regulatory pathway critical for Salmonella virulence and stress resistance. The enzymes PoxA and YjeK coordinately attach a unique beta-amino acid onto a highly conserved...

  20. Promoter recognition by bacterial alternative sigma factors: the price of high selectivity?

    Science.gov (United States)

    Feklistov, Andrey; Darst, Seth A

    2009-10-15

    A key step in bacterial transcription initiation is melting of the double-stranded promoter DNA by the RNA polymerase holoenzyme. Primary sigma factors mediate the melting of thousands of promoters through a conserved set of aromatic amino acids. Alternative sigmas, which direct transcription of restricted regulons, lack the full set of melting residues. In this issue of Genes & Development, Koo and colleagues (pp. 2426-2436) show that introducing the primary sigma melting residues into alternative sigmas relaxes their promoter specificity, pointing to a trade-off of reduced promoter melting capacity for increased promoter stringency. PMID:19833764

  1. Regulation of specialized metabolism by WRKY transcription factors.

    Science.gov (United States)

    Schluttenhofer, Craig; Yuan, Ling

    2015-02-01

    WRKY transcription factors (TFs) are well known for regulating plant abiotic and biotic stress tolerance. However, much less is known about how WRKY TFs affect plant-specialized metabolism. Analysis of WRKY TFs regulating the production of specialized metabolites emphasizes the values of the family outside of traditionally accepted roles in stress tolerance. WRKYs with conserved roles across plant species seem to be essential in regulating specialized metabolism. Overall, the WRKY family plays an essential role in regulating the biosynthesis of important pharmaceutical, aromatherapy, biofuel, and industrial components, warranting considerable attention in the forthcoming years. PMID:25501946

  2. Bacterial translational regulations: high diversity between all mRNAs and major role in gene expression

    Directory of Open Access Journals (Sweden)

    Picard Flora

    2012-10-01

    Full Text Available Abstract Background In bacteria, the weak correlations at the genome scale between mRNA and protein levels suggest that not all mRNAs are translated with the same efficiency. To experimentally explore mRNA translational level regulation at the systemic level, the detailed translational status (translatome of all mRNAs was measured in the model bacterium Lactococcus lactis in exponential phase growth. Results Results demonstrated that only part of the entire population of each mRNA species was engaged in translation. For transcripts involved in translation, the polysome size reached a maximum of 18 ribosomes. The fraction of mRNA engaged in translation (ribosome occupancy and ribosome density were not constant for all genes. This high degree of variability was analyzed by bioinformatics and statistical modeling in order to identify general rules of translational regulation. For most of the genes, the ribosome density was lower than the maximum value revealing major control of translation by initiation. Gene function was a major translational regulatory determinant. Both ribosome occupancy and ribosome density were particularly high for transcriptional regulators, demonstrating the positive role of translational regulation in the coordination of transcriptional networks. mRNA stability was a negative regulatory factor of ribosome occupancy and ribosome density, suggesting antagonistic regulation of translation and mRNA stability. Furthermore, ribosome occupancy was identified as a key component of intracellular protein levels underlining the importance of translational regulation. Conclusions We have determined, for the first time in a bacterium, the detailed translational status for all mRNAs present in the cell. We have demonstrated experimentally the high diversity of translational states allowing individual gene differentiation and the importance of translation-level regulation in the complex process linking gene expression to protein

  3. Bacterial Infections and Osteoclastogenesis Regulators in Men and Women with Cholesteatoma.

    Science.gov (United States)

    Likus, Wirginia; Siemianowicz, Krzysztof; Markowski, Jarosław; Wiaderkiewicz, Jan; Kostrząb-Zdebel, Anna; Jura-Szołtys, Edyta; Dziubdziela, Włodzimierz; Wiaderkiewicz, Ryszard; Łos, Marek J

    2016-06-01

    One of the most distinct features of middle ear cholesteatoma is bone destruction. Aetiology of cholesteatoma is thought to be multifactorial. Endotoxins produced by bacteria are thought to initiate the inflammation process in the middle ear leading to cholesteatoma. There are physiological differences in bone metabolism between men and women. The aim of our study was the immunohistochemical evaluation of the contents of two key components of the OPG/RANK/RANKL triad-RANKL and OPG in cholesteatoma, to analyse if there are any differences between the sexes and to evaluate the bacteria species isolated from cholesteatoma just before surgical treatment and to evaluate their plausible influence on the expression of OPG and RANKL in cholesteatoma. Twenty-one adult patients with acquired cholesteatoma who underwent surgery were analysed. There were no statistically significant differences in the expression of both regulators of osteoclastogenesis between the sexes. In 38.1 % patients cholesteatoma was not infected, whereas in 61.9 % patients various bacterial infections or mycosis were found. The most frequently isolated species was Pseudomonas aeruginosa (14.29 % infections) followed by Staphylococcus aureus (9.52 % infections). There were no statistically significant differences in expression of both OPG and RANKL between uninfected and infected cholesteatomas. PMID:26584851

  4. A Salmonella small non-coding RNA facilitates bacterial invasion and intracellular replication by modulating the expression of virulence factors.

    Directory of Open Access Journals (Sweden)

    Hao Gong

    2011-09-01

    Full Text Available Small non-coding RNAs (sRNAs that act as regulators of gene expression have been identified in all kingdoms of life, including microRNA (miRNA and small interfering RNA (siRNA in eukaryotic cells. Numerous sRNAs identified in Salmonella are encoded by genes located at Salmonella pathogenicity islands (SPIs that are commonly found in pathogenic strains. Whether these sRNAs are important for Salmonella pathogenesis and virulence in animals has not been reported. In this study, we provide the first direct evidence that a pathogenicity island-encoded sRNA, IsrM, is important for Salmonella invasion of epithelial cells, intracellular replication inside macrophages, and virulence and colonization in mice. IsrM RNA is expressed in vitro under conditions resembling those during infection in the gastrointestinal tract. Furthermore, IsrM is found to be differentially expressed in vivo, with higher expression in the ileum than in the spleen. IsrM targets the mRNAs coding for SopA, a SPI-1 effector, and HilE, a global regulator of the expression of SPI-1 proteins, which are major virulence factors essential for bacterial invasion. Mutations in IsrM result in disregulation of expression of HilE and SopA, as well as other SPI-1 genes whose expression is regulated by HilE. Salmonella with deletion of isrM is defective in bacteria invasion of epithelial cells and intracellular replication/survival in macrophages. Moreover, Salmonella with mutations in isrM is attenuated in killing animals and defective in growth in the ileum and spleen in mice. Our study has shown that IsrM sRNA functions as a pathogenicity island-encoded sRNA directly involved in Salmonella pathogenesis in animals. Our results also suggest that sRNAs may represent a distinct class of virulence factors that are important for bacterial infection in vivo.

  5. The Phytohormone Ethylene Enhances Cellulose Production, Regulates CRP/FNRKx Transcription and Causes Differential Gene Expression within the Bacterial Cellulose Synthesis Operon of Komagataeibacter (Gluconacetobacter) xylinus ATCC 53582

    Science.gov (United States)

    Augimeri, Richard V.; Strap, Janice L.

    2015-01-01

    Komagataeibacter (formerly Gluconacetobacter) xylinus ATCC 53582 is a plant-associated model organism for bacterial cellulose (BC) biosynthesis. This bacterium inhabits the carposphere where it interacts with fruit through the bi-directional transfer of phytohormones. The majority of research regarding K. xylinus has been focused on identifying and characterizing structural and regulatory factors that control BC biosynthesis, but its ecophysiology has been generally overlooked. Ethylene is a phytohormone that regulates plant development in a variety of ways, but is most commonly known for its positive role on fruit ripening. In this study, we utilized ethephon (2-chloroethylphosphonic acid) to produce in situ ethylene to investigate the effects of this phytohormone on BC production and the expression of genes known to be involved in K. xylinus BC biosynthesis (bcsA, bcsB, bcsC, bcsD, cmcAx, ccpAx and bglAx). Using pellicle assays and reverse transcription quantitative polymerase chain reaction (RT-qPCR), we demonstrate that ethephon-derived ethylene enhances BC directly in K. xylinus by up-regulating the expression of bcsA and bcsB, and indirectly though the up-regulation of cmcAx, ccpAx, and bglAx. We confirm that IAA directly decreases BC biosynthesis by showing that IAA down-regulates bcsA expression. Similarly, we confirm that ABA indirectly influences BC biosynthesis by showing it does not affect the expression of bcs operon genes. In addition, we are the first to report the ethylene and indole-3-acetic acid (IAA) induced differential expression of genes within the bacterial cellulose synthesis (bcs) operon. Using bioinformatics we have identified a novel phytohormone-regulated CRP/FNRKx transcription factor and provide evidence that it influences BC biosynthesis in K. xylinus. Lastly, utilizing current and previous data, we propose a model for the phytohormone-mediated fruit-bacteria interactions that K. xylinus experiences in nature. PMID:26733991

  6. The phytohormone ethylene enhances bacterial cellulose production, regulates CRP/FNRKx transcription and causes differential gene expression within the cellulose synthesis operon of Komagataeibacter (Gluconacetobacter xylinus ATCC 53582

    Directory of Open Access Journals (Sweden)

    Richard Vincent Augimeri

    2015-12-01

    Full Text Available Komagataeibacter (formerly Gluconacetobacter xylinus ATCC 53582 is a plant-associated model organism for bacterial cellulose (BC biosynthesis. This bacterium inhabits the carposphere where it interacts with fruit through the bi-directional transfer of phytohormones. The majority of research regarding K. xylinus has been focused on identifying and characterizing structural and regulatory factors that control BC biosynthesis, but its ecophysiology has been generally overlooked. Ethylene is a phytohormone that regulates plant development in a variety of ways, but is most commonly known for its positive role on fruit ripening. In this study, we utilized ethephon (2-chloroethylphosphonic acid to produce in situ ethylene to investigate the effects of this phytohormone on BC production and the expression of genes known to be involved in K. xylinus BC biosynthesis (bcsA, bcsB, bcsC, bcsD, cmcAx, ccpAx and bglAx. Using pellicle assays and reverse transcription quantitative polymerase chain reaction (RT-qPCR, we demonstrate that ethephon-derived ethylene enhances BC directly in K. xylinus by up-regulating the expression of bcsA and bcsB, and indirectly though the up-regulation of cmcAx, ccpAx and bglAx. We confirm that IAA directly decreases BC biosynthesis by showing that IAA down-regulates bcsA expression. Similarly, we confirm that ABA indirectly influences BC biosynthesis by showing it does not affect the expression of bcs operon genes. In addition, we are the first to report the ethylene and indole-3-acetic acid (IAA induced differential expression of genes within the bacterial cellulose synthesis (bcs operon. Using bioinformatics we have identified a novel phytohormone-regulated CRP/FNRKx transcription factor and provide evidence that it influences BC biosynthesis in K. xylinus. Lastly, utilizing current and previous data, we propose a model for the phytohormone-mediated fruit-bacteria interactions that K. xylinus experiences in nature.

  7. The Phytohormone Ethylene Enhances Cellulose Production, Regulates CRP/FNRKx Transcription and Causes Differential Gene Expression within the Bacterial Cellulose Synthesis Operon of Komagataeibacter (Gluconacetobacter) xylinus ATCC 53582.

    Science.gov (United States)

    Augimeri, Richard V; Strap, Janice L

    2015-01-01

    Komagataeibacter (formerly Gluconacetobacter) xylinus ATCC 53582 is a plant-associated model organism for bacterial cellulose (BC) biosynthesis. This bacterium inhabits the carposphere where it interacts with fruit through the bi-directional transfer of phytohormones. The majority of research regarding K. xylinus has been focused on identifying and characterizing structural and regulatory factors that control BC biosynthesis, but its ecophysiology has been generally overlooked. Ethylene is a phytohormone that regulates plant development in a variety of ways, but is most commonly known for its positive role on fruit ripening. In this study, we utilized ethephon (2-chloroethylphosphonic acid) to produce in situ ethylene to investigate the effects of this phytohormone on BC production and the expression of genes known to be involved in K. xylinus BC biosynthesis (bcsA, bcsB, bcsC, bcsD, cmcAx, ccpAx and bglAx). Using pellicle assays and reverse transcription quantitative polymerase chain reaction (RT-qPCR), we demonstrate that ethephon-derived ethylene enhances BC directly in K. xylinus by up-regulating the expression of bcsA and bcsB, and indirectly though the up-regulation of cmcAx, ccpAx, and bglAx. We confirm that IAA directly decreases BC biosynthesis by showing that IAA down-regulates bcsA expression. Similarly, we confirm that ABA indirectly influences BC biosynthesis by showing it does not affect the expression of bcs operon genes. In addition, we are the first to report the ethylene and indole-3-acetic acid (IAA) induced differential expression of genes within the bacterial cellulose synthesis (bcs) operon. Using bioinformatics we have identified a novel phytohormone-regulated CRP/FNRKx transcription factor and provide evidence that it influences BC biosynthesis in K. xylinus. Lastly, utilizing current and previous data, we propose a model for the phytohormone-mediated fruit-bacteria interactions that K. xylinus experiences in nature. PMID:26733991

  8. Role of bacterial γ-glutamyltranspeptidase as a novel virulence factor in bone-resorbing pathogenesis.

    Science.gov (United States)

    Kim, Jinmoon; Jang, Sungil; Kim, Aeryun; Su, Hanfu; Gunawardhana, Niluka; Jeon, Yeong-Eui; Bak, Eun Jung; Kim, Ji-Hye; Cha, Jeong-Heon

    2016-05-01

    Mammalian γ-glutamyltranspeptidase (GGT) has been identified as a bone-resorbing factor. Since GGT of Bacillus subtilis exhibits similarity in their primary structure and enzymatic characteristics with mammalian GGTs, the bone-resorbing activity of bacterial GGT was examined in this study. Osteoclastogenesis was performed in a co-culture system of mouse calvaria-derived osteoblasts and bone marrow cells. A conditioned medium from GGT-overproducing B. subtilis culture showed significantly higher activity of osteoclast formation than a conditioned medium from wild-type B. subtilis culture. Recombinant GGT (rGGT) of wild-type B. subtilis and an enzymatic activity-defected rGGT of B. subtilis 2288 mutant were expressed in Escherichia coli and purified using His tag. Both purified rGGTs induced similar levels of osteoclastogenesis, suggesting that B. subtilis GGT possesses virulent bone-resorbing activity and its activity is probably independent of its enzymatic activity. Furthermore, a recombinant protein of B. subtilis GGT heavy subunit (Bs rGGT/H) showed strong activity of osteoclastogenesis while the light subunit failed to show strong activity, suggesting that the bone-resorbing activity is mainly located at the heavy subunit. More importantly, the GGT enzymatic activity may not be required for this virulence activity since the light subunit contains the catalytic pocket. In addition, B. subtilis rGGT stimulated mRNA expressions of receptor activator of nuclear factor kappa-B ligand (RANKL) and cyclooxygenase-2 (COX-2), while an osteoprotegerin inhibited the osteoclast formation induced by Bs rGGT/H. This is the first demonstration that bacterial GGT itself is sufficient to act as a bone-resorbing virulence factor via RANKL-dependent pathway. Therefore, it can be hypothesized that GGT of periodontopathic bacteria may play an important role as a virulence factor in bone destruction. PMID:27095459

  9. BATF: Bringing (in) Another Th17-regulating Factor

    Institute of Scientific and Technical Information of China (English)

    Gustavo J. Martinez; Chen Dong

    2009-01-01

    T helper (Th) 17 cells are a recently identified subset of T cells that regulate tissue inflammation, and RORγt and RORα have been shown to be Th17-specific transcription factors that mediate Th17 cell generation. A new study of Batf-deficient mice shows that this AP-1 family transcription factor also regulates Th17 cell differentiation by binding to Th17-associated gene promoters and by maintaining RORa and RORgt expression, shedding new lights on current clinical modulation of Th17 cell function in inflammatory diseases.

  10. Regulation of bacterial communities through antimicrobial activity by the coral holobiont.

    Science.gov (United States)

    Kvennefors, E Charlotte E; Sampayo, Eugenia; Kerr, Caroline; Vieira, Genyess; Roff, George; Barnes, Andrew C

    2012-04-01

    Interactions between corals and associated bacteria and amongst these bacterial groups are likely to play a key role in coral health. However, the complexity of these interactions is poorly understood. We investigated the functional role of specific coral-associated bacteria in maintaining microbial communities on the coral Acropora millepora (Ehrenberg 1834) and the ability of coral mucus to support or inhibit bacterial growth. Culture-independent techniques were used to assess bacterial community structures whilst bacterial culture was employed to assess intra- and inter-specific antimicrobial activities of bacteria. Members of Pseudoalteromonas and ribotypes closely related to Vibrio coralliilyticus displayed potent antimicrobial activity against a range of other cultured isolates and grew readily on detached coral mucus. Although such bacterial ribotypes would be expected to have a competitive advantage, they were rare or absent on intact and healthy coral colonies growing in situ (analysed using denaturing gradient gel electrophoresis and 16S rRNA gene sequencing). The most abundant bacterial ribotypes found on healthy corals were Gammaproteobacteria, previously defined as type A coral associates. Our results indicate that this group of bacteria and specific members of the Alphaproteobacteria described here as 'type B associates' may be important functional groups for coral health. We suggest that bacterial communities on coral are kept in check by a combination of host-derived and microbial interactions and that the type A associates in particular may play a key role in maintaining stability of microbial communities on healthy coral colonies. PMID:21984347

  11. Key factors for causing poplar Ice Nucleation Active bacterial canker and its control techniques

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    The isolation, culture and the active determination of poplar ice nucleation active (INA) bacteria and the inoculation tests in laboratory and field were conducted, and the varieties, distribution and number of poplar INA bacteria and its pathogenicity and freezing injury property were determined. The study results showed that the INA bacteria widely spread on poplar in Northeast China and caused the frozen injury for poplar under the frost condition in Spring or Autumn, which was the key factor to induce INA bacterial canker. Through evaluation and investigation of different poplar varieties and inoculation tests, fine disease-resistant varieties and strains of poplar suitable for Northeast China were selected. Further tests for strong seedling showed that burying cuttings in sand and covering with plastic film could effectively avoid the frostbite, frozen and drought damage, reduce INA bacteria infection, and promote poplar growth. INA bacterial canker was detected early by highly specialized antiserums of INA bacteria and the agglutinated test of ring-shaped boundary surface. The inducers such as streptomycin, phenylmercuric acetae, salicylic acid and heat-killed bacteria to immerse cuttings, have obvious induced disease-resistant effect. Before poplar sprouted in early spring, through spraying the solution of frostbite agent, the control effect also was obvious.

  12. Temporal scaling of bacterial taxa is influenced by both stochastic and deterministic ecological factors.

    Science.gov (United States)

    van der Gast, Christopher J; Ager, Duane; Lilley, Andrew K

    2008-06-01

    Microorganisms operate at a range of spatial and temporal scales acting as key drivers of ecosystem properties. Therefore, many key questions in microbial ecology require the consideration of both spatial and temporal scales. Spatial scaling, in particular the species-area relationship (SAR), has a long history in ecology and has recently been addressed in microbial ecology. However, the temporal analogue of the SAR, the species-time relationship, has received far less attention even in the science of general ecology. Here we focus upon the role of temporal scaling in microbial ecological patterns by coupling molecular characterization of bacterial communities in discrete island (bioreactor) systems with a macroecological approach. Our findings showed that the temporal scaling exponent (slope), and therefore taxa turnover of the bacterial taxa-time relationship decreased as selective pressure (industrial wastewater concentration) increased. Also, as the concentration of industrial wastewater increased across the bioreactors, we observed a gradual switch from stochastic community assembly to more deterministic (niche)-based considerations. The identification of broad-scale statistical patterns is particularly relevant to microbial ecology, as it is frequently difficult to identify individual species or their functions. In this study, we identify wide-reaching statistical patterns of diversity and show that they are shaped by the prevalent underlying ecological factors. PMID:18205822

  13. Role of bacterial infection in the epigenetic regulation of Wnt antagonist WIF1 by PRC2 protein EZH2

    OpenAIRE

    Roy, Badal C.; Subramaniam, Dharmalingam; Ahmed, Ishfaq; Jala, Venkatakrishna R.; Hester, Christina; Greiner, K. Allen; Haribabu, Bodduluri; Anant, Shrikant; Umar, Shahid

    2014-01-01

    The Enhancer of Zeste Homolog-2 (EZH2) represses gene transcription through histone H3 lysine-27-trimethylation (H3K27me3). Citrobacter rodentium (CR) promotes crypt hyperplasia and tumorigenesis by aberrantly regulating Wnt/β-catenin signaling. We aimed at investigating EZH2’s role in epigenetically regulating Wnt/β-catenin signaling following bacterial infection. NIH:Swiss outbred and Apc Min/+ mice were infected with CR (108cfu); BLT1−/−ApcMin/+ mice, AOM/DSS-treated mice and de-identified...

  14. Unusual Heme Binding in the Bacterial Iron Response Regulator Protein (Irr): Spectral Characterization of Heme Binding to Heme Regulatory Motif

    OpenAIRE

    Ishikawa, Haruto; Nakagaki, Megumi; Bamba, Ai; Uchida, Takeshi; Hori, Hiroshi; O'Brian, Mark R.; Iwai, Kazuhiro; Ishimori, Koichiro

    2011-01-01

    We characterized heme binding in the bacterial iron response regulator (Irr) protein, which is a simple heme-regulated protein having a single “heme-regulatory motif”, HRM, and plays a key role in the iron homeostasis of a nitrogen fixing bacterium. The heme titration to wild-type and mutant Irr clearly showed that Irr has two heme binding sites: one of the heme binding sites is in the HRM, where 29Cys is the axial ligand, and the other one, the secondary heme binding site, is located outside...

  15. Bacterial Overgrowth in the Cystic Fibrosis Transmembrane Conductance Regulator Null Mouse Small Intestine

    OpenAIRE

    Norkina, Oxana; Burnett, Tim G.; De Lisle, Robert C

    2004-01-01

    We recently reported the inflammation of the cystic fibrosis (CF) mouse small intestine, and we hypothesized bacterial overgrowth as a possible cause. Quantitative PCR of bacterial 16S genomic DNA in the CF mouse small intestine revealed an increase of greater than 40-fold compared to controls. Sequencing of 16S PCR products and Gram staining showed that the majority of bacteria in the CF mouse intestine were gram negative. Bacteria were observed to colonize the mucus that accumulates in the ...

  16. CRISPR-Cas systems: new players in gene regulation and bacterial physiology

    OpenAIRE

    Sampson, Timothy R.; Weiss, David S.

    2014-01-01

    CRISPR-Cas systems are bacterial defenses against foreign nucleic acids derived from bacteriophages, plasmids or other sources. These systems are targeted in an RNA-dependent, sequence-specific manner, and are also adaptive, providing protection against previously encountered foreign elements. In addition to their canonical function in defense against foreign nucleic acid, their roles in various aspects of bacterial physiology are now being uncovered. We recently revealed a role for a Cas9-ba...

  17. A Common Structural Motif in the Binding of Virulence Factors to Bacterial Secretion Chaperones

    International Nuclear Information System (INIS)

    Salmonella invasion protein A (SipA) is translocated into host cells by a type III secretion system (T3SS) and comprises two regions: one domain binds its cognate type III secretion chaperone, InvB, in the bacterium to facilitate translocation, while a second domain functions in the host cell, contributing to bacterial uptake by polymerizing actin. We present here the crystal structures of the SipA chaperone binding domain (CBD) alone and in complex with InvB. The SipA CBD is found to consist of a nonglobular polypeptide as well as a large globular domain, both of which are necessary for binding to InvB. We also identify a structural motif that may direct virulence factors to their cognate chaperones in a diverse range of pathogenic bacteria. Disruption of this structural motif leads to a destabilization of several chaperone-substrate complexes from different species, as well as an impairment of secretion in Salmonella

  18. Myocardin-related Transcription Factor Regulates Nox4 Protein Expression

    DEFF Research Database (Denmark)

    Rozycki, Matthew; Bialik, Janne Folke; Speight, Pam;

    2016-01-01

    TGFβ-induced expression of the NADPH oxidase Nox4 is essential for fibroblast-myofibroblast transition. Rho has been implicated in Nox4 regulation, but the underlying mechanisms are largely unknown. Myocardin-related transcription factor (MRTF), a Rho/actin polymerization-controlled coactivator of...... translocation of MRTF. Because the Nox4 promoter harbors a serum response factor/MRTF cis-element (CC(A/T)6GG box), we asked if MRTF (and thus cytoskeleton organization) could regulate Nox4 expression. We show that Nox4 protein is robustly induced in kidney tubular cells exclusively by combined application of...... contact uncoupling and TGFβ. Nox4 knockdown abrogates epithelial-myofibroblast transition-associated reactive oxygen species production. Laser capture microdissection reveals increased Nox4 expression in the tubular epithelium also during obstructive nephropathy. MRTF down-regulation/inhibition suppresses...

  19. New insights in the bacterial spore resistance to extreme terrestrial and extraterrestrial factors

    Science.gov (United States)

    Moeller, Ralf; Horneck, Gerda; Reitz, Guenther

    Based on their unique resistance to various space parameters, Bacillus endospores are one of the model systems used for astrobiological studies. The extremely high resistance of bacterial endospores to environmental stress factors has intrigued researchers since long time and many characteristic spore features, especially those involved in the protection of spore DNA, have already been uncovered. The disclosure of the complete genomic sequence of Bacillus subtilis 168, one of the often used astrobiological model system, and the rapid development of tran-scriptional microarray techniques have opened new opportunities of gaining further insights in the enigma of spore resistance. Spores of B. subtilis were exposed to various extreme ter-restrial and extraterrestrial stressors to reach a better understanding of the DNA protection and repair strategies, which them to cope with the induced DNA damage. Following physical stress factors of environmental importance -either on Earth or in space -were selected for this thesis: (i) mono-and polychromatic UV radiation, (ii) ionizing radiation, (iii) exposure to ultrahigh vacuum; and (iv) high shock pressures simulating meteorite impacts. To reach a most comprehensive understanding of spore resistance to those harsh terrestrial or simulated extraterrestrial conditions, a standardized experimental protocol of the preparation and ana-lyzing methods was established including the determination of the following spore responses: (i) survival, (ii) induced mutations, (iii) DNA damage, (iv) role of different repair pathways by use of a set of repair deficient mutants, and (v) transcriptional responses during spore germi-nation by use of genome-wide transcriptome analyses and confirmation by RT-PCR. From this comprehensive set of data on spore resistance to a variety of environmental stress parameters a model of a "built-in" transcriptional program of bacterial spores in response to DNA damaging treatments to ensure DNA restoration

  20. Redox-dependent regulation of epidermal growth factor receptor signaling.

    Science.gov (United States)

    Heppner, David E; van der Vliet, Albert

    2016-08-01

    Tyrosine phosphorylation-dependent cell signaling represents a unique feature of multicellular organisms, and is important in regulation of cell differentiation and specialized cell functions. Multicellular organisms also contain a diverse family of NADPH oxidases (NOXs) that have been closely linked with tyrosine kinase-based cell signaling and regulate tyrosine phosphorylation via reversible oxidation of cysteine residues that are highly conserved within many proteins involved in this signaling pathway. An example of redox-regulated tyrosine kinase signaling involves the epidermal growth factor receptor (EGFR), a widely studied receptor system with diverse functions in normal cell biology as well as pathologies associated with oxidative stress such as cancer. The purpose of this Graphical Redox Review is to highlight recently emerged concepts with respect to NOX-dependent regulation of this important signaling pathway. PMID:26722841

  1. Functional equivalence of HMGA- and histone H1-like domains in a bacterial transcriptional factor

    OpenAIRE

    García-Heras, Francisco; Padmanabhan, S.; Murillo, Francisco J.; Elías-Arnanz, Montserrat

    2009-01-01

    Histone H1 and high-mobility group A (HMGA) proteins compete dynamically to modulate chromatin structure and regulate DNA transactions in eukaryotes. In prokaryotes, HMGA-like domains are known only in Myxococcus xanthus CarD and its Stigmatella aurantiaca ortholog. These have an N-terminal module absent in HMGA that interacts with CarG (a zinc-associated factor that does not bind DNA) to form a stable complex essential in regulating multicellular development, light-induced carotenogenesis, a...

  2. DMPD: Lipopolysaccharide sensing an important factor in the innate immune response toGram-negative bacterial infections: benefits and hazards of LPShypersensitivity. [Dynamic Macrophage Pathway CSML Database

    Lifescience Database Archive (English)

    Full Text Available se toGram-negative bacterial infections: benefits and hazards of LPShypersensitivity. Freudenberg MA, Tchapt...portant factor in the innate immune response toGram-negative bacterial infections: benefits and hazards of L...une response toGram-negative bacterial infections: benefits and hazards of LPShyp

  3. NIK1, a host factor specialized in antiviral defense or a novel general regulator of plant immunity?

    Science.gov (United States)

    Machado, Joao P B; Brustolini, Otavio J B; Mendes, Giselle C; Santos, Anésia A; Fontes, Elizabeth P B

    2015-11-01

    NIK1 is a receptor-like kinase involved in plant antiviral immunity. Although NIK1 is structurally similar to the plant immune factor BAK1, which is a key regulator in plant immunity to bacterial pathogens, the NIK1-mediated defenses do not resemble BAK1 signaling cascades. The underlying mechanism for NIK1 antiviral immunity has recently been uncovered. NIK1 activation mediates the translocation of RPL10 to the nucleus, where it interacts with LIMYB to fully down-regulate translational machinery genes, resulting in translation inhibition of host and viral mRNAs and enhanced tolerance to begomovirus. Therefore, the NIK1 antiviral immunity response culminates in global translation suppression, which represents a new paradigm for plant antiviral defenses. Interestingly, transcriptomic analyses in nik1 mutant suggest that NIK1 may suppress antibacterial immune responses, indicating a possible opposite effect of NIK1 in bacterial and viral infections. PMID:26335701

  4. Salt marsh sediment characteristics as key regulators on the efficiency of hydrocarbons bioremediation by Juncus maritimus rhizospheric bacterial community.

    Science.gov (United States)

    Ribeiro, Hugo; Almeida, C Marisa R; Magalhães, Catarina; Bordalo, Adriano A; Mucha, Ana P

    2015-01-01

    Mitigation of petroleum hydrocarbons was investigated during a 5-month greenhouse experiment, to assess the rhizoremediation (RR) potential in sediments with different characteristics colonized by Juncus maritimus, a salt marsh plant commonly found in temperate estuaries. Furthermore, the efficiency of two bioremediation treatments namely biostimulation (BS) by the addition of nutrients, and bioaugmentation (BA) by addition of indigenous microorganisms, was tested in combination with RR. The effect of the distinct treatments on hydrocarbon degradation, root biomass weight, and bacterial community structure was assessed. Our result showed higher potential for hydrocarbon degradation (evaluated by total petroleum hydrocarbon analysis) in coarse rhizosediments with low organic matter (OM), than rhizosediments with high OM, and small size particles. Moreover, the bacterial community structure was shaped according to the rhizosediment characteristics, highlighting the importance of specific microbe-particle associations to define the structure of rhizospheric bacterial communities, rather than external factors, such as hydrocarbon contamination or the applied treatments. The potential for hydrocarbon RR seems to depend on root system development and bacterial diversity, since biodegradation efficiencies were positively related with these two parameters. Treatments with higher root biomass, and concomitantly with higher bacterial diversity yielded higher hydrocarbon degradation. Moreover, BS and BA did not enhance hydrocarbons RR. In fact, it was observed that higher nutrient availability might interfere with root growth and negatively influence hydrocarbon degradation performance. Therefore, our results suggested that to conduct appropriate hydrocarbon bioremediation strategies, the effect of sediment characteristics on root growth/exploration should be taken into consideration, a feature not explored in previous studies. Furthermore, strategies aiming for the recovery

  5. Brain-derived neurotrophic factor, food intake regulation, and obesity.

    Science.gov (United States)

    Rosas-Vargas, Haydeé; Martínez-Ezquerro, José Darío; Bienvenu, Thierry

    2011-08-01

    Brain-derived neurotrophic factor (BDNF) is a neurotrophin that plays a fundamental role in development and plasticity of the central nervous system (CNS). It is currently recognized as a major participant in the regulation of food intake. Multiple studies have shown that different regulators of appetite such as leptin, insulin and pancreatic polypeptide (PP) potentially exert anorexigenic effects through BDNF. Low circulating levels of BDNF are associated with a higher risk of eating disorders such as anorexia nervosa (AN) and bulimia nervosa (BN). Strict food restriction reduces BDNF and may trigger binge-eating episodes and weight gain. The existence of mutations that cause haploinsufficiency of BDNF as well as some genetic variants, notably the BDNF p.Val66Met polymorphism, are also associated with the development of obese phenotypes and hyperphagia. However, association of the Met allele with AN and BN, which have different phenotypic characteristics, shows clearly the existence of other relevant factors that regulate eating behavior. This may, in part, be explained by the epigenetic regulation of BDNF through mechanisms like DNA methylation and histone acetylation. Environmental factors, primarily during early development, are crucial to the establishment of these stable but reversible changes that alter the transcriptional expression and are transgenerationally heritable, with potential concomitant effects on the development of eating disorders and body weight control. PMID:21945389

  6. Regulation of Pseudomonas aeruginosa virulence factors by two novel RNA thermometers

    Science.gov (United States)

    Grosso-Becerra, María Victoria; Croda-García, Gerardo; Merino, Enrique; Servín-González, Luis; Mojica-Espinosa, Raúl; Soberón-Chávez, Gloria

    2014-01-01

    In a number of bacterial pathogens, the production of virulence factors is induced at 37 °C; this effect is often regulated by mRNA structures formed in the 5′ untranslated region (UTR) that block translation initiation of genes at environmental temperatures. At 37 °C, the RNA structures become unstable and ribosomes gain access to their binding sites in the mRNAs. Pseudomonas aeruginosa is an important opportunistic pathogen and the expression of many of its virulence-associated traits is regulated by the quorum-sensing (QS) response, but the effect of temperature on virulence-factor expression is not well-understood. The aim of this work is the characterization of the molecular mechanism involved in thermoregulation of QS-dependent virulence-factor production. We demonstrate that traits that are dependent on the QS transcriptional regulator RhlR have a higher expression at 37 °C, correlating with a higher RhlR concentration as measured by Western blot. We also determined, using gene fusions and point mutations, that RhlR thermoregulation is a posttranscriptional effect dependent on an RNA thermometer of the ROSE (Repression Of heat-Shock gene Expression) family. This RNA element regulates the expression of the rhlAB operon, involved in rhamnolipid production, and of the downstream rhlR gene. We also identified a second functional thermometer in the 5′ UTR of the lasI gene. We confirmed that these RNA thermometers are the main mechanism of thermoregulation of QS-dependent gene expression in P. aeruginosa using quantitative real-time PCR. This is the first description, to our knowledge, of a ROSE element regulating the expression of virulence traits and of an RNA thermometer controlling multiple genes in an operon through a polar effect. PMID:25313031

  7. Identification and characterization of transcription factors regulating Arabidopsis HAK5.

    Science.gov (United States)

    Hong, Jong-Pil; Takeshi, Yoshizumi; Kondou, Youichi; Schachtman, Daniel P; Matsui, Minami; Shin, Ryoung

    2013-09-01

    Potassium (K) is an essential macronutrient for plant growth and reproduction. HAK5, an Arabidopsis high-affinity K transporter gene, plays an important role in K uptake. Its expression is up-regulated in response to K deprivation and is rapidly down-regulated when sufficient K levels have been re-established. To identify transcription factors regulating HAK5, an Arabidopsis TF FOX (Transcription Factor Full-length cDNA Over-eXpressor) library containing approximately 800 transcription factors was used to transform lines previously transformed with a luciferase reporter gene whose expression was driven by the HAK5 promoter. When grown under sufficient K levels, 87 lines with high luciferase activity were identified, and endogenous HAK5 expression was confirmed in 27 lines. Four lines overexpressing DDF2 (Dwarf and Delayed Flowering 2), JLO (Jagged Lateral Organs), TFII_A (Transcription initiation Factor II_A gamma chain) and bHLH121 (basic Helix-Loop-Helix 121) were chosen for further characterization by luciferase activity, endogenous HAK5 level and root growth in K-deficient conditions. Further analysis showed that the expression of these transcription factors increased in response to low K and salt stress. In comparison with controls, root growth under low K conditions was better in each of these four TF FOX lines. Activation of HAK5 expression by these four transcription factors required at least 310 bp of upstream sequence of the HAK5 promoter. These results indicate that at least these four transcription factors can bind to the HAK5 promoter in response to K limitation and activate HAK5 expression, thus allowing plants to adapt to nutrient stress. PMID:23825216

  8. Coevolution between Stop Codon Usage and Release Factors in Bacterial Species.

    Science.gov (United States)

    Wei, Yulong; Wang, Juan; Xia, Xuhua

    2016-09-01

    Three stop codons in bacteria represent different translation termination signals, and their usage is expected to depend on their differences in translation termination efficiency, mutation bias, and relative abundance of release factors (RF1 decoding UAA and UAG, and RF2 decoding UAA and UGA). In 14 bacterial species (covering Proteobacteria, Firmicutes, Cyanobacteria, Actinobacteria and Spirochetes) with cellular RF1 and RF2 quantified, UAA is consistently over-represented in highly expressed genes (HEGs) relative to lowly expressed genes (LEGs), whereas UGA usage is the opposite even in species where RF2 is far more abundant than RF1. UGA usage relative to UAG increases significantly with PRF2 [=RF2/(RF1 + RF2)] as expected from adaptation between stop codons and their decoders. PRF2 is > 0.5 over a wide range of AT content (measured by PAT3 as the proportion of AT at third codon sites), but decreases rapidly toward zero at the high range of PAT3 This explains why bacterial lineages with high PAT3 often have UGA reassigned because of low RF2. There is no indication that UAG is a minor stop codon in bacteria as claimed in a recent publication. The claim is invalid because of the failure to apply the two key criteria in identifying a minor codon: (1) it is least preferred by HEGs (or most preferred by LEGs) and (2) it corresponds to the least abundant decoder. Our results suggest a more plausible explanation for why UAA usage increases, and UGA usage decreases, with PAT3, but UAG usage remains low over the entire PAT3 range. PMID:27297468

  9. A response regulator promotes Francisella tularensis intramacrophage growth by repressing an anti-virulence factor.

    Science.gov (United States)

    Ramsey, Kathryn M; Dove, Simon L

    2016-08-01

    The orphan response regulator PmrA is essential for the intramacrophage growth and survival of Francisella tularensis. PmrA was thought to promote intramacrophage growth by binding directly to promoters on the Francisella Pathogenicity Island (FPI) and positively regulating the expression of FPI genes, which encode a Type VI secretion system required for intramacrophage growth. Using both ChIP-Seq and RNA-Seq we identify those regions of the F. tularensis chromosome occupied by PmrA and those genes that are regulated by PmrA. We find that PmrA associates with 252 distinct regions of the F. tularensis chromosome, but exerts regulatory effects at only a few of these locations. Rather than by functioning directly as an activator of FPI gene expression we present evidence that PmrA promotes intramacrophage growth by repressing the expression of a single target gene we refer to as priM (PmrA-repressed inhibitor of intramacrophage growth). Our findings thus indicate that the role of PmrA in facilitating intracellular growth is to repress a previously unknown anti-virulence factor. PriM is the first bacterially encoded factor to be described that can interfere with the intramacrophage growth and survival of F. tularensis. PMID:27169554

  10. Factors Associated with Bacterial Vaginosis among Women Who Have Sex with Women: A Systematic Review.

    Directory of Open Access Journals (Sweden)

    Dana S Forcey

    Full Text Available Women who have sex with women (WSW have a higher burden of bacterial vaginosis (BV than heterosexual women; studies of risk factors specific to this population are limited. We summarised current knowledge regarding risk factors for BV among WSW by systematic review.This systematic review was conducted according to the PRISMA statement. PUBMED, EMBASE, Web of Science and The Cochrane Library were searched to 31st December, 2014.1 WSW included in the study population; 2 accepted BV diagnostic method; 3 investigated or could extrapolate factors(s associated with BV acquisition, persistence or transmission in WSW specifically by comparing BV positive to BV negative women. Search was limited to English-language publications.A limited number of studies have investigated BV in WSW. Of 71 unique references, 18 full-text articles were assessed and 14 studies fulfilled inclusion criteria. BV was positively associated with higher numbers of female partners, both lifetime and in the three months prior to diagnosis, and confirmed BV in a female partner, but inconsistently associated with partners' BV history or symptoms. BV was not associated with ethnicity, vaginal douching or hormonal contraception. The impact of specific sexual activities, male sexual contact, smoking and the menstrual cycle varied considerably between study populations.BV in WSW is associated with increased numbers of recent and past female partners and confirmed BV in a female partner. There are limited studies of BV in WSW populations, and research is needed to further elucidate risk factors for BV among WSW. However these data provide epidemiological evidence that BV risk in women is directly related to exposure to other female partners and a partner with BV, providing support for the concept that BV is likely to be transmitted between women.CRD42014009536 (PROSPERO.

  11. mADP-RTs: Versatile virulence factors from bacterial pathogens of plants and mammals

    Directory of Open Access Journals (Sweden)

    Lennart eWirthmueller

    2012-06-01

    Full Text Available Mono ADP-ribosyltransferases (mADP-RTs are a family of enzymes that cleave NAD+ and covalently attach the ADP-ribosyl moiety to target proteins. mADP-RTs are well established as important virulence factors of bacteria that infect mammals. Cholera toxin, pertussis toxin and diphteria toxin are three of the best-known examples of mADP-RTs. They modify host target proteins in order to promote infection and/or killing of the host cell. Despite low sequence similarity at the primary amino acid level, mADP-RTs share a conserved core catalytic fold and structural biology has made important contributions to elucidating how mADP-RTs modify mammalian host targets. Recently, mADP-RTs were shown to be present in plant pathogenic bacteria, suggesting that mADP-RTs are also important virulence factors of plant pathogens. Crystal structures of plant pathogenic bacterial mADP-RTs are also now available. Here we review the structure/function of mADP-RTs from pathogens of mammals and plants, highlighting both commonalities and differences.

  12. Anaerobes and bacterial vaginosis in pregnancy: virulence factors contributing to vaginal colonisation.

    Science.gov (United States)

    Africa, Charlene W J; Nel, Janske; Stemmet, Megan

    2014-07-01

    The aetiology and pathogenesis of bacterial vaginosis (BV) is unclear but it appears to be associated with factors that disrupt the normal acidity of the vagina thus altering the equilibrium between the normal vaginal microbiota. BV has serious implications for female morbidity, including reports of pelvic inflammatory disease, adverse pregnancy outcomes, increased susceptibility to sexually transmitted infections and infertility. This paper reviewed new available information regarding possible factors contributing to the establishment of the BV vaginal biofilm, examined the proposed role of anaerobic microbial species recently detected by new culture-independent methods and discusses developments related to the effects of BV on human pregnancy. The literature search included Pubmed (NLM), LISTA (EBSCO), and Web of Science. Because of the complexity and diversity of population groups, diagnosis and methodology used, no meta-analysis was performed. Several anaerobic microbial species previously missed in the laboratory diagnosis of BV have been revealed while taking cognisance of newly proposed theories of infection, thereby improving our understanding and knowledge of the complex aetiology and pathogenesis of BV and its perceived role in adverse pregnancy outcomes. PMID:25014248

  13. Anaerobes and Bacterial Vaginosis in Pregnancy: Virulence Factors Contributing to Vaginal Colonisation

    Directory of Open Access Journals (Sweden)

    Charlene W. J. Africa

    2014-07-01

    Full Text Available The aetiology and pathogenesis of bacterial vaginosis (BV is unclear but it appears to be associated with factors that disrupt the normal acidity of the vagina thus altering the equilibrium between the normal vaginal microbiota. BV has serious implications for female morbidity, including reports of pelvic inflammatory disease, adverse pregnancy outcomes, increased susceptibility to sexually transmitted infections and infertility. This paper reviewed new available information regarding possible factors contributing to the establishment of the BV vaginal biofilm, examined the proposed role of anaerobic microbial species recently detected by new culture-independent methods and discusses developments related to the effects of BV on human pregnancy. The literature search included Pubmed (NLM, LISTA (EBSCO, and Web of Science. Because of the complexity and diversity of population groups, diagnosis and methodology used, no meta-analysis was performed. Several anaerobic microbial species previously missed in the laboratory diagnosis of BV have been revealed while taking cognisance of newly proposed theories of infection, thereby improving our understanding and knowledge of the complex aetiology and pathogenesis of BV and its perceived role in adverse pregnancy outcomes.

  14. Cleavage factor Im (CFIm) as a regulator of alternative polyadenylation.

    Science.gov (United States)

    Hardy, Jessica G; Norbury, Chris J

    2016-08-15

    Most mammalian protein coding genes are subject to alternative cleavage and polyadenylation (APA), which can generate distinct mRNA 3'UTRs with differing regulatory potential. Although this process has been intensely studied in recent years, it remains unclear how and to what extent cleavage site selection is regulated under different physiological conditions. The cleavage factor Im (CFIm) complex is a core component of the mammalian cleavage machinery, and the observation that its depletion causes transcriptome-wide changes in cleavage site use makes it a key candidate regulator of APA. This review aims to summarize current knowledge of the CFIm complex, and explores the evidence surrounding its potential contribution to regulation of APA. PMID:27528751

  15. Transcription factor regulation of pancreatic organogenesis, differentiation and maturation.

    Science.gov (United States)

    Dassaye, Reshmi; Naidoo, Strini; Cerf, Marlon E

    2016-01-01

    Lineage tracing studies have revealed that transcription factors play a cardinal role in pancreatic development, differentiation and function. Three transitions define pancreatic organogenesis, differentiation and maturation. In the primary transition, when pancreatic organogenesis is initiated, there is active proliferation of pancreatic progenitor cells. During the secondary transition, defined by differentiation, there is growth, branching, differentiation and pancreatic cell lineage allocation. The tertiary transition is characterized by differentiated pancreatic cells that undergo further remodeling, including apoptosis, replication and neogenesis thereby establishing a mature organ. Transcription factors function at multiple levels and may regulate one another and auto-regulate. The interaction between extrinsic signals from non-pancreatic tissues and intrinsic transcription factors form a complex gene regulatory network ultimately culminating in the different cell lineages and tissue types in the developing pancreas. Mutations in these transcription factors clinically manifest as subtypes of diabetes mellitus. Current treatment for diabetes is not curative and thus, developmental biologists and stem cell researchers are utilizing knowledge of normal pancreatic development to explore novel therapeutic alternatives. This review summarizes current knowledge of transcription factors involved in pancreatic development and β-cell differentiation in rodents. PMID:26404721

  16. Ciliary Neurotrophic Factor Receptor Regulation of Adult Forebrain Neurogenesis

    OpenAIRE

    Lee, Nancy; Batt, Myra K.; Cronier, Brigitte A.; Jackson, Michele C.; Bruno Garza, Jennifer L; Trinh, Dennis S.; Mason, Carter O.; Spearry, Rachel P.; Bhattacharya, Shayon; Robitz, Rachel; Nakafuku, Masato; MacLennan, A. John

    2013-01-01

    Appropriately targeted manipulation of endogenous neural stem progenitor (NSP) cells may contribute to therapies for trauma, stroke, and neurodegenerative disease. A prerequisite to such therapies is a better understanding of the mechanisms regulating adult NSP cells in vivo. Indirect data suggest that endogenous ciliary neurotrophic factor (CNTF) receptor signaling may inhibit neuronal differentiation of NSP cells. We challenged subventricular zone (SVZ) cells in vivo with low concentrations...

  17. MGMT expression: insights into its regulation. 1. Epigenetic factors

    OpenAIRE

    Iatsyshyna A. P.

    2013-01-01

    O6-methylguanine-DNA methyltransferase (MGMT) is the DNA repair enzyme responsible for removing of alkylation adducts from the O6-guanine in DNA. Despite MGMT prevents mutations and cell death, this enzyme can provide resistance of cancer cells to alkylating agents of chemotherapy. The high intra- and inter-individual variations in the human MGMT expression level have been observed indicating to a complicated regulation of this gene. This review is focused on the study of epigenetic factors w...

  18. Bone Cell Autophagy Is Regulated by Environmental Factors

    OpenAIRE

    Zahm, Adam M.; Bohensky, Jolene; Adams, Christopher S.; Shapiro, Irving M.; Srinivas, Vickram

    2011-01-01

    The goal of this investigation was to ascertain whether bone cells undergo autophagy and to determine if this process is regulated by environmental factors. We showed that osteocytes in both murine and human cortical bone display a punctuate distribution of microtubule-associated protein light chain 3, indicative of autophagy. In addition, we noted a basal level of autophagy in preosteocyte-like murine long bone-derived osteocytic (MLO)-A5 cells. Autophagy was upregulated following nutrient d...

  19. Regulation of the immune response to bacterial lipopolysaccharide by adherent cells.

    OpenAIRE

    Citron, M O; Michael, J G

    1981-01-01

    Immune response to bacterial lipopolysaccharide is usually short lived, but it often reappears without additional stimulus in a cyclic fashion. Activated adherent cells, presumably macrophages, were found to have a role in the reduction of the immune response to Escherichia coli O127 lipopolysaccharide. The suppressive activity of the adherent cells was abrogated before renewal of the responsiveness.

  20. Bacterial profiles of saliva in relation to diet, lifestyle factors, and socioeconomic status

    Directory of Open Access Journals (Sweden)

    Daniel Belstrøm

    2014-04-01

    Full Text Available Background and objective: The bacterial profile of saliva is composed of bacteria from different oral surfaces. The objective of this study was to determine whether different diet intake, lifestyle, or socioeconomic status is associated with characteristic bacterial saliva profiles. Design: Stimulated saliva samples from 292 participants with low levels of dental caries and periodontitis, enrolled in the Danish Health Examination Survey (DANHES, were analyzed for the presence of approximately 300 bacterial species by means of the Human Oral Microbe Identification Microarray (HOMIM. Using presence and levels (mean HOMIM-value of bacterial probes as endpoints, the influence of diet intake, lifestyle, and socioeconomic status on the bacterial saliva profile was analyzed by Mann–Whitney tests with Benjamini–Hochberg's correction for multiple comparisons and principal component analysis. Results: Targets for 131 different probes were identified in 292 samples, with Streptococcus and Veillonella being the most predominant genera identified. Two bacterial taxa (Streptococcus sobrinus and Eubacterium [11][G-3] brachy were more associated with smokers than non-smokers (adjusted p-value<0.01. Stratification of the group based on extreme ends of the parameters age, gender, alcohol consumption, body mass index (BMI, and diet intake had no statistical influence on the composition of the bacterial profile of saliva. Conversely, differences in socioeconomic status were reflected by the bacterial profiles of saliva. Conclusions: The bacterial profile of saliva seems independent of diet intake, but influenced by smoking and maybe socioeconomic status.

  1. Microphthalmia transcription factor regulates pancreatic β-cell function.

    Science.gov (United States)

    Mazur, Magdalena A; Winkler, Marcus; Ganic, Elvira; Colberg, Jesper K; Johansson, Jenny K; Bennet, Hedvig; Fex, Malin; Nuber, Ulrike A; Artner, Isabella

    2013-08-01

    Precise regulation of β-cell function is crucial for maintaining blood glucose homeostasis. Pax6 is an essential regulator of β-cell-specific factors like insulin and Glut2. Studies in the developing eye suggest that Pax6 interacts with Mitf to regulate pigment cell differentiation. Here, we show that Mitf, like Pax6, is expressed in all pancreatic endocrine cells during mouse postnatal development and in the adult islet. A Mitf loss-of-function mutation results in improved glucose tolerance and enhanced insulin secretion but no increase in β-cell mass in adult mice. Mutant β-cells secrete more insulin in response to glucose than wild-type cells, suggesting that Mitf is involved in regulating β-cell function. In fact, the transcription of genes critical for maintaining glucose homeostasis (insulin and Glut2) and β-cell formation and function (Pax4 and Pax6) is significantly upregulated in Mitf mutant islets. The increased Pax6 expression may cause the improved β-cell function observed in Mitf mutant animals, as it activates insulin and Glut2 transcription. Chromatin immunoprecipitation analysis shows that Mitf binds to Pax4 and Pax6 regulatory regions, suggesting that Mitf represses their transcription in wild-type β-cells. We demonstrate that Mitf directly regulates Pax6 transcription and controls β-cell function. PMID:23610061

  2. Spatial Distribution of Bacterial Communities Driven by Multiple Environmental Factors in a Beach Wetland of the Largest Freshwater Lake in China

    Directory of Open Access Journals (Sweden)

    Xia eDing

    2015-02-01

    Full Text Available The spatial distributions of bacterial communities may be driven by multiple environmental factors. Thus, understanding the relationships between bacterial distribution and environmental factors is critical for understanding wetland stability and the functioning of freshwater lakes. However, little research on the bacterial communities in deep sediment layers exists. In this study, thirty clone libraries of 16S rRNA were constructed from a beach wetland of the Poyang Lake along both horizontal (distance to the water-land junction and vertical (sediment depth gradients to assess the effects of sediment properties on bacterial community structure and diversity. Our results showed that bacterial diversity increased along the horizontal gradient and decreased along the vertical gradient. The heterogeneous sediment properties along gradients substantially affected the dominant bacterial groups at the phylum and species levels. For example, the NH4+ concentration decreased with increasing depth, which was positively correlated with the relative abundance of Alphaproteobacteria. The changes in bacterial diversity and dominant bacterial groups showed that the top layer had a different bacterial community structure than the deeper layers. Principal component analysis revealed that both gradients, not each gradient independently, contributed to the shift in the bacterial community structure. A multiple linear regression model explained the changes in bacterial diversity and richness along the depth and distance gradients. Overall, our results suggest that spatial gradients associated with sediment properties shaped the bacterial communities in the Poyang Lake beach wetland.

  3. Activation of p38α in T cells regulates the intestinal host defense against attaching and effacing bacterial infections

    OpenAIRE

    Shim, Eun-Jin; Bang, Bo Ram; Kang, Seung-Goo; Ma, Jianhui; Otsuka, Motoyuki; Kang, Jiman; Stahl, Martin; Han, Jiahuai; Xiao, Changchun; Vallance, Bruce A.; Kang, Young Jun

    2013-01-01

    Intestinal infections by attaching and effacing (A/E) bacterial pathogens cause severe colitis and bloody diarrhea. Although p38α in intestine epithelial cells (IEC) plays an important role in promoting protection against A/E bacteria by regulating T cell recruitment, its impact on immune responses remains unclear. In this study, we show that activation of p38α in T cells is critical for the clearance of the A/E pathogen Citrobacter rodentium. Mice deficient of p38α in T cells, but not in mac...

  4. Factors related to occurrence and distribution of selected bacterial and protozoan pathogens in Pennsylvania streams

    Science.gov (United States)

    Duris, Joseph W.; Reif, Andrew G.; Donna A. Crouse; Isaacs, Natasha M.

    2013-01-01

    The occurrence and distribution of fecal indicator bacteria (FIB) and bacterial and protozoan pathogens are controlled by diverse factors. To investigate these factors in Pennsylvania streams, 217 samples were collected quarterly from a 27-station water-quality monitoring network from July 2007 through August 2009. Samples were analyzed for concentrations of Escherichia coli (EC) and enterococci (ENT) indicator bacteria, concentrations of Cryptosporidium oocysts and Giardia cysts, and the presence of four genes related to pathogenic types of EC (eaeA, stx2, stx1, rfbO157) plus three microbial source tracking (MST) gene markers that are also associated with pathogenic ENT and EC (esp, LTIIa, STII). Water samples were concurrently analyzed for basic water chemistry, physical measures of water quality, nutrients, metals, and a suite of 79 organic compounds that included hormones, pharmaceuticals, and antibiotics. For each sample location, stream discharge was measured by using standardized methods at the time of sample collection, and ancillary sample site information, such as land use and geological characteristics, was compiled. Samples exceeding recreational water quality criteria were more likely to contain all measured pathogen genes but notCryptosporidium or Giardia (oo)cysts. FIB and Giardia density and frequency of eaeA gene occurrence were significantly related to season. When discharge at a sampling location was high (>75th percentile of daily mean discharge), there were greater densities of FIB and Giardia, and the stx2, rfbO157, STII, and esp genes were found more frequently than at other discharge conditions. Giardia occurrence was likely related to nonpoint sources, which are highly influential during seasonal overland transport resulting from snowmelt and elevated precipitation in late winter and spring in Pennsylvania. When MST markers of human, swine, or bovine origin were present, samples more frequently carried the eaeA, stx2

  5. Measurement of the copy number of the master quorum-sensing regulator of a bacterial cell.

    Science.gov (United States)

    Teng, Shu-Wen; Wang, Yufang; Tu, Kimberly C; Long, Tao; Mehta, Pankaj; Wingreen, Ned S; Bassler, Bonnie L; Ong, N P

    2010-05-19

    Quorum-sensing is the mechanism by which bacteria communicate and synchronize group behaviors. Quantitative information on parameters such as the copy number of particular quorum-sensing proteins should contribute strongly to understanding how the quorum-sensing network functions. Here, we show that the copy number of the master regulator protein LuxR in Vibrio harveyi can be determined in vivo by exploiting small-number fluctuations of the protein distribution when cells undergo division. When a cell divides, both its volume and LuxR protein copy number, N, are partitioned with slight asymmetries. We measured the distribution functions describing the partitioning of the protein fluorescence and the cell volume. The fluorescence distribution is found to narrow systematically as the LuxR population increases, whereas the volume partitioning is unchanged. Analyzing these changes statistically, we determined that N = 80-135 dimers at low cell density and 575 dimers at high cell density. In addition, we measured the static distribution of LuxR over a large (3000) clonal population. Combining the static and time-lapse experiments, we determine the magnitude of the Fano factor of the distribution. This technique has broad applicability as a general in vivo technique for measuring protein copy number and burst size. PMID:20441767

  6. Neuronal Goα and CAPS regulate behavioral and immune responses to bacterial pore-forming toxins.

    Directory of Open Access Journals (Sweden)

    Ferdinand C O Los

    Full Text Available Pore-forming toxins (PFTs are abundant bacterial virulence factors that attack host cell plasma membranes. Host defense mechanisms against PFTs described to date all function in the host tissue that is directly attacked by the PFT. Here we characterize a rapid and fully penetrant cessation of feeding of Caenorhabditis elegans in response to PFT attack. We demonstrate via analyses of C. elegans mutants that inhibition of feeding by PFT requires the neuronal G protein Goα subunit goa-1, and that maintenance of this response requires neuronally expressed calcium activator for protein secretion (CAPS homolog unc-31. Independently from their role in feeding cessation, we find that goa-1 and unc-31 are additionally required for immune protection against PFTs. We thus demonstrate that the behavioral and immune responses to bacterial PFT attack involve the cross-talk between the nervous system and the cells directly under attack.

  7. Using artificial neural networks to predict the distribution of bacterial crop diseases from biotic and abiotic factors

    Directory of Open Access Journals (Sweden)

    Michael J. Watts

    2012-03-01

    Full Text Available Constructing accurate computational global distribution models is an important first step towards the understanding of bacterial crop diseases and can lead to insights into the biology of disease-causing bacteria species. We constructed artificial neural network models of the geographic distribution of six bacterial diseases of crop plants. These ANN modelled the distribution of these species from regional climatic factors and from regional assemblages of host crop plants. Multiple ANN were combined into ensembles using statistical methods. Tandem ANN, where an ANN combined the outputs of individual ANN, were also investigated. We found that for all but one species, superior accuracies were attained by methods that combined biotic and abiotic factors. These combinations were produced by both ensemble and cascaded ANN. This shows that firstly, ANN are able to model the geographic distribution of bacterial crop diseases, and secondly, that combining abiotic and biotic factors is necessary to achieve high modelling accuracies. The work reported in this paper therefore provides a basis for constructing models of the distribution of bacterial crop diseases.

  8. Bacterial profiles of saliva in relation to diet, lifestyle factors, and socioeconomic status

    DEFF Research Database (Denmark)

    Belstrøm, Daniel; Holmstrup, Palle; Nielsen, Claus H;

    2014-01-01

    BACKGROUND AND OBJECTIVE: The bacterial profile of saliva is composed of bacteria from different oral surfaces. The objective of this study was to determine whether different diet intake, lifestyle, or socioeconomic status is associated with characteristic bacterial saliva profiles. DESIGN......: Stimulated saliva samples from 292 participants with low levels of dental caries and periodontitis, enrolled in the Danish Health Examination Survey (DANHES), were analyzed for the presence of approximately 300 bacterial species by means of the Human Oral Microbe Identification Microarray (HOMIM). Using...... presence and levels (mean HOMIM-value) of bacterial probes as endpoints, the influence of diet intake, lifestyle, and socioeconomic status on the bacterial saliva profile was analyzed by Mann-Whitney tests with Benjamini-Hochberg's correction for multiple comparisons and principal component analysis...

  9. Regulation of bacterial sulfate reduction and hydrogen sulfide fluxes in the central Namibian coastal upwelling zone

    DEFF Research Database (Denmark)

    Bruchert, V.; Jørgensen, BB; Neumann, K.;

    2003-01-01

    low capacity to oxidize and trap sulfide. The inner shelf break marks the seaward border of sulfidic bottom waters, and separates two different regimes of bacterial sulfate reduction. In the sulfidic bottom waters on the shelf, up to 55% of sulfide oxidation is mediated by the large nitrate......The coastal upwelling system off central Namibia is one of the most productive regions of the oceans and is characterized by frequently occurring shelf anoxia with severe effects for the benthic life and fisheries. We present data on water column dissolved oxygen, sulfide, nitrate and nitrite, pore...... water profiles for dissolved,sulfide and sulfate, S-35-sulfate reduction rates, as well as bacterial counts of large sulfur bacteria from 20 stations across the continental shelf and slope. The stations covered two transects and included the inner shelf with its anoxic and extremely oxygen...

  10. Canine uterine bacterial infection induces upregulation of proteolysis-related genes and downregulation of homeobox and zinc finger factors.

    Directory of Open Access Journals (Sweden)

    Ragnvi Hagman

    Full Text Available BACKGROUND: Bacterial infection with the severe complication of sepsis is a frequent and serious condition, being a major cause of death worldwide. To cope with the plethora of occurring bacterial infections there is therefore an urgent need to identify molecular mechanisms operating during the host response, in order both to identify potential targets for therapeutic intervention and to identify biomarkers for disease. Here we addressed this issue by studying global gene expression in uteri from female dogs suffering from spontaneously occurring uterine bacterial infection. PRINCIPAL FINDINGS: The analysis showed that almost 800 genes were significantly (p2-fold in the uteri of diseased animals. Among these were numerous chemokine and cytokine genes, as well as genes associated with inflammatory cell extravasation, anti-bacterial action, the complement system and innate immune responses, as well as proteoglycan-associated genes. There was also a striking representation of genes associated with proteolysis. Robust upregulation of immunoglobulin components and genes involved in antigen presentation was also evident, indicating elaboration of a strong adaptive immune response. The bacterial infection was also associated with a significant downregulation of almost 700 genes, of which various homeobox and zinc finger transcription factors were highly represented. CONCLUSIONS/SIGNIFICANCE: Together, these finding outline the molecular patterns involved in bacterial infection of the uterus. The study identified altered expression of numerous genes not previously implicated in bacterial disease, and several of these may be evaluated for potential as biomarkers of disease or as therapeutic targets. Importantly, since humans and dogs show genetic similarity and develop diseases that share many characteristics, the molecular events identified here are likely to reflect the corresponding situation in humans afflicted by similar disease.

  11. Global Regulation of Virulence Determinants During Plant Colonization in the Bacterial Phytopathogen, Pantoea stewartii subsp. stewartii

    OpenAIRE

    Burbank, Lindsey

    2014-01-01

    Pantoea stewartii subsp. stewartii, the etiological agent of Stewart's wilt, is a bacterial pathogen of sweet corn which colonizes both the apoplast and xylem tissues. During the initial stages of the infection process, the pathogen forms water-soaked lesions through lysis of the plant cells, followed by colonization of the xylem tissue where it can grow to high cell densities and form biofilms. Biofilm formation within the xylem vessels can block water flow, causing the characteristic wiltin...

  12. Regulation of Pulmonary and Systemic Bacterial Lipopolysaccharide Responses in Transgenic Mice Expressing Human Elafin

    OpenAIRE

    Sallenave, J-M; Cunningham, G A; James, R M; McLachlan, G.; Haslett, C

    2003-01-01

    The control of lung inflammation is of paramount importance in a variety of acute pathologies, such as pneumonia, the acute respiratory distress syndrome, and sepsis. It is becoming increasingly apparent that local innate immune responses in the lung are negatively influenced by systemic inflammation. This is thought to be due to a local deficit in cytokine responses by alveolar macrophages and neutrophils following systemic bacterial infection and the development of a septic response. Recent...

  13. Sequential evolution of bacterial morphology by co-option of a developmental regulator

    OpenAIRE

    Jiang, Chao; Brown, Pamela J.B.; Ducret, Adrien; Brun, Yves V.

    2014-01-01

    What mechanisms underlie the transitions responsible for the diverse shapes observed in the living world? While bacteria display a myriad of morphologies 1 , the mechanisms responsible for the evolution of bacterial cell shape are not understood. We investigated morphological diversity in a group of bacteria that synthesize an appendage-like extension of the cell envelope called the stalk 2,3 . The location and number of stalks varies among species, as exemplified by three distinct sub-cellul...

  14. EFFECTS OF PSYCHOTROPIC DRUGS AS BACTERIAL EFFLUX PUMP INHIBITORS ON QUORUM SENSING REGULATED BEHAVIORS

    OpenAIRE

    Aynur Aybey; Alev Usta; Elif Demirkan

    2014-01-01

    Psychotropic drugs are known to have antimicrobial activity against several groups of microorganisms. The antidepressant agents such as duloxetine, paroxetine, hydroxyzine and venlafaxine are shown to act as efflux pump inhibitors in bacterial cells. In order to the investigation of the effects of psychotropic drugs were determined for clinically significant pathogens by using standart broth microdillusion method. The anti-quorum sensing (anti-QS) activity of psychotropic drugs was tested aga...

  15. Regulation of Memory Formation by the Transcription Factor XBP1

    Directory of Open Access Journals (Sweden)

    Gabriela Martínez

    2016-02-01

    Full Text Available Contextual memory formation relies on the induction of new genes in the hippocampus. A polymorphism in the promoter of the transcription factor XBP1 was identified as a risk factor for Alzheimer’s disease and bipolar disorders. XBP1 is a major regulator of the unfolded protein response (UPR, mediating adaptation to endoplasmic reticulum (ER stress. Using a phenotypic screen, we uncovered an unexpected function of XBP1 in cognition and behavior. Mice lacking XBP1 in the nervous system showed specific impairment of contextual memory formation and long-term potentiation (LTP, whereas neuronal XBP1s overexpression improved performance in memory tasks. Gene expression analysis revealed that XBP1 regulates a group of memory-related genes, highlighting brain-derived neurotrophic factor (BDNF, a key component in memory consolidation. Overexpression of BDNF in the hippocampus reversed the XBP1-deficient phenotype. Our study revealed an unanticipated function of XBP1 in cognitive processes that is apparently unrelated to its role in ER stress.

  16. Jasmonate-responsive transcription factors regulating plant secondary metabolism.

    Science.gov (United States)

    Zhou, Meiliang; Memelink, Johan

    2016-01-01

    Plants produce a large variety of secondary metabolites including alkaloids, glucosinolates, terpenoids and phenylpropanoids. These compounds play key roles in plant-environment interactions and many of them have pharmacological activity in humans. Jasmonates (JAs) are plant hormones which induce biosynthesis of many secondary metabolites. JAs-responsive transcription factors (TFs) that regulate the JAs-induced accumulation of secondary metabolites belong to different families including AP2/ERF, bHLH, MYB and WRKY. Here, we give an overview of the types and functions of TFs that have been identified in JAs-induced secondary metabolite biosynthesis, and highlight their similarities and differences in regulating various biosynthetic pathways. We review major recent developments regarding JAs-responsive TFs mediating secondary metabolite biosynthesis, and provide suggestions for further studies. PMID:26876016

  17. MGMT expression: insights into its regulation. 1. Epigenetic factors

    Directory of Open Access Journals (Sweden)

    Iatsyshyna A. P.

    2013-03-01

    Full Text Available O6-methylguanine-DNA methyltransferase (MGMT is the DNA repair enzyme responsible for removing of alkylation adducts from the O6-guanine in DNA. Despite MGMT prevents mutations and cell death, this enzyme can provide resistance of cancer cells to alkylating agents of chemotherapy. The high intra- and inter-individual variations in the human MGMT expression level have been observed indicating to a complicated regulation of this gene. This review is focused on the study of epigenetic factors which could be potentially involved in regulation of the human MGMT gene expression. These include chromatin remodeling via histone modifications and DNA methylation of promoter region and gene body, as well as RNA-based mechanisms, alternative splicing, protein post- translational modifications, and other.

  18. Heterotrophic bacterial production: Relationships to biological and abiological factors in estuarine environments

    International Nuclear Information System (INIS)

    Ecotoxicological effects of creosote contamination on benthic bacterial communities in the Elizabeth River, Virginia were investigated using both structural an functional microbial parameters. Results indicated that cell specific and total heterotrophic bacterial production parameters were depressed in a dose-dependent manner with increasing sediment PAH concentrations. Toxicity effects upon production were modified by temporal trends associated with temperature as well as spatial sediment characteristics. Of the parameters employed, the tritiated thymidine production assay was found to be the most sensitive for detection of ecotoxicological effects. Bacterial abundance and production were examined during a destratification event in the lower James River, Virginia. Bacterial abundance, although significantly different between stations, did not change over the study. Bacterial production (3H-Tdr incorporation) in surface waters was significantly less during the mixed period 187 μg C·1-1· d-1 compared to the most stratified state (324μg C·1-1· d-1). Correlations between bacteria and chlorophyll were diminished during the mixed period. Total and flagellate specific grazing rates upon bacteria were reduced during the onset of destratification. Relationships between bacterial and nutrient parameters also indicated a strong influence of destratification. These results indicate that destratification changes trophic interactions within the microbial loop, which are not necessarily reflected in temporal patterns of bacterial abundance. Bacterioplankton production, and ammonium assimilation and remineralization were examined between April and August 1988 in the lower York River, Va

  19. Genome-wide identification of Hsp70 genes in channel catfish and their regulated expression after bacterial infection.

    Science.gov (United States)

    Song, Lin; Li, Chao; Xie, Yangjie; Liu, Shikai; Zhang, Jiaren; Yao, Jun; Jiang, Chen; Li, Yun; Liu, Zhanjiang

    2016-02-01

    Heat shock proteins 70/110 (Hsp70/110) are a family of conserved ubiquitously expressed heat shock proteins which are produced by cells in response to exposure to stressful conditions. Besides the chaperone and housekeeping functions, they are also known to be involved in immune response during infection. In this study, we identified 16 Hsp70/110 geness in channel catfish (Ictalurus punctatus) through in silico analysis using RNA-Seq and genome databases. Among them 12 members of Hsp70 (Hspa) family and 4 members of Hsp110 (Hsph) family were identified. Phylogenetic and syntenic analyses provided strong evidence in supporting the orthologies of these HSPs. In addition, we also determined the expression patterns of Hsp70/110 genes after Flavobacterium columnare and Edwardsiella ictaluri infections by meta-analyses, for the first time in channel catfish. Ten out of sixteen genes were significantly up/down-regulated after bacterial challenges. Specifically, nine genes were found significantly expressed in gill after F. columnare infection. Two genes were found significantly expressed in intestine after E. ictaluri infection. Pathogen-specific pattern and tissue-specific pattern were found in the two infections. The significantly regulated expressions of catfish Hsp70 genes after bacterial infections suggested their involvement in immune response in catfish. PMID:26693666

  20. Hydrogen peroxide sensing, signaling and regulation of transcription factors

    Directory of Open Access Journals (Sweden)

    H. Susana Marinho

    2014-01-01

    Full Text Available The regulatory mechanisms by which hydrogen peroxide (H2O2 modulates the activity of transcription factors in bacteria (OxyR and PerR, lower eukaryotes (Yap1, Maf1, Hsf1 and Msn2/4 and mammalian cells (AP-1, NRF2, CREB, HSF1, HIF-1, TP53, NF-κB, NOTCH, SP1 and SCREB-1 are reviewed. The complexity of regulatory networks increases throughout the phylogenetic tree, reaching a high level of complexity in mammalians. Multiple H2O2 sensors and pathways are triggered converging in the regulation of transcription factors at several levels: (1 synthesis of the transcription factor by upregulating transcription or increasing both mRNA stability and translation; (ii stability of the transcription factor by decreasing its association with the ubiquitin E3 ligase complex or by inhibiting this complex; (iii cytoplasm–nuclear traffic by exposing/masking nuclear localization signals, or by releasing the transcription factor from partners or from membrane anchors; and (iv DNA binding and nuclear transactivation by modulating transcription factor affinity towards DNA, co-activators or repressors, and by targeting specific regions of chromatin to activate individual genes. We also discuss how H2O2 biological specificity results from diverse thiol protein sensors, with different reactivity of their sulfhydryl groups towards H2O2, being activated by different concentrations and times of exposure to H2O2. The specific regulation of local H2O2 concentrations is also crucial and results from H2O2 localized production and removal controlled by signals. Finally, we formulate equations to extract from typical experiments quantitative data concerning H2O2 reactivity with sensor molecules. Rate constants of 140 M−1 s−1 and ≥1.3 × 103 M−1 s−1 were estimated, respectively, for the reaction of H2O2 with KEAP1 and with an unknown target that mediates NRF2 protein synthesis. In conclusion, the multitude of H2O2 targets and mechanisms provides an opportunity for

  1. Transcription Factor Hepatocyte Nuclear Factor-1β Regulates Renal Cholesterol Metabolism.

    Science.gov (United States)

    Aboudehen, Karam; Kim, Min Soo; Mitsche, Matthew; Garland, Kristina; Anderson, Norma; Noureddine, Lama; Pontoglio, Marco; Patel, Vishal; Xie, Yang; DeBose-Boyd, Russell; Igarashi, Peter

    2016-08-01

    HNF-1β is a tissue-specific transcription factor that is expressed in the kidney and other epithelial organs. Humans with mutations in HNF-1β develop kidney cysts, and HNF-1β regulates the transcription of several cystic disease genes. However, the complete spectrum of HNF-1β-regulated genes and pathways is not known. Here, using chromatin immunoprecipitation/next generation sequencing and gene expression profiling, we identified 1545 protein-coding genes that are directly regulated by HNF-1β in murine kidney epithelial cells. Pathway analysis predicted that HNF-1β regulates cholesterol metabolism. Expression of dominant negative mutant HNF-1β or kidney-specific inactivation of HNF-1β decreased the expression of genes that are essential for cholesterol synthesis, including sterol regulatory element binding factor 2 (Srebf2) and 3-hydroxy-3-methylglutaryl-CoA reductase (Hmgcr). HNF-1β mutant cells also expressed lower levels of cholesterol biosynthetic intermediates and had a lower rate of cholesterol synthesis than control cells. Additionally, depletion of cholesterol in the culture medium mitigated the inhibitory effects of mutant HNF-1β on the proteins encoded by Srebf2 and Hmgcr, and HNF-1β directly controlled the renal epithelial expression of proprotein convertase subtilisin-like kexin type 9, a key regulator of cholesterol uptake. These findings reveal a novel role of HNF-1β in a transcriptional network that regulates intrarenal cholesterol metabolism. PMID:26712526

  2. Defining human insulin-like growth factor I gene regulation.

    Science.gov (United States)

    Mukherjee, Aditi; Alzhanov, Damir; Rotwein, Peter

    2016-08-01

    Growth hormone (GH) plays an essential role in controlling somatic growth and in regulating multiple physiological processes in humans and other species. Insulin-like growth factor I (IGF-I), a conserved, secreted 70-amino acid peptide, is a critical mediator of many of the biological effects of GH. Previous studies have demonstrated that GH rapidly and potently promotes IGF-I gene expression in rodents and in some other mammals through the transcription factor STAT5b, leading to accumulation of IGF-I mRNAs and production of IGF-I. Despite this progress, very little is known about how GH or other trophic factors control human IGF1 gene expression, in large part because of the absence of any cellular model systems that robustly express IGF-I. Here, we have addressed mechanisms of regulation of human IGF-I by GH after generating cells in which the IGF1 chromosomal locus has been incorporated into a mouse cell line. Using this model, we found that physiological levels of GH rapidly stimulate human IGF1 gene transcription and identify several potential transcriptional enhancers in chromatin that bind STAT5b in a GH-regulated way. Each of the putative enhancers also activates a human IGF1 gene promoter in reconstitution experiments in the presence of the GH receptor, STAT5b, and GH. Thus we have developed a novel experimental platform that now may be used to determine how human IGF1 gene expression is controlled under different physiological and pathological conditions. PMID:27406741

  3. Fibroblast Growth Factor 21 Mediates Glycemic Regulation by Hepatic JNK

    OpenAIRE

    Santiago Vernia; Julie Cavanagh-Kyros; Tamera Barrett; Cathy Tournier; Roger J. Davis

    2016-01-01

    The cJun NH2-terminal kinase (JNK) signaling pathway is implicated in metabolic syndrome, including dysregulated blood glucose concentration and insulin resistance. Fibroblast growth factor 21 (FGF21) is a target of the hepatic JNK signaling pathway and may contribute to the regulation of glycemia. To test the role of FGF21, we established mice with selective ablation of the Fgf21 gene in hepatocytes. FGF21-deficiency in the liver caused marked loss of FGF21 protein circulating in the blood. ...

  4. Epidermal Growth Factor Regulates Hematopoietic Regeneration Following Radiation Injury

    OpenAIRE

    Doan, Phuong L.; Himburg, Heather A.; Helms, Katherine; Russell, J. Lauren; Fixsen, Emma; Quarmyne, Mamle; Harris, Jeffrey R; Deoliviera, Divino; Sullivan, Julie M.; Chao, Nelson J.; Kirsch, David G.; Chute, John P

    2013-01-01

    The mechanisms which regulate HSC regeneration following myelosuppressive injury are not well understood. We identified epidermal growth factor (EGF) to be highly enriched in the bone marrow (BM) serum of mice bearing deletion of Bak and Bax in Tie2+ cells (Tie2Cre;Bak1−/−;Baxfl/− mice), which displayed radioprotection of the HSC pool and 100% survival following lethal dose total body irradiation (TBI). BM HSCs from wild type mice expressed functional EGFR and systemic administration of EGF p...

  5. Regulation of cardiac microRNAs by serum response factor

    Directory of Open Access Journals (Sweden)

    Wei Jeanne Y

    2011-02-01

    Full Text Available Abstract Serum response factor (SRF regulates certain microRNAs that play a role in cardiac and skeletal muscle development. However, the role of SRF in the regulation of microRNA expression and microRNA biogenesis in cardiac hypertrophy has not been well established. In this report, we employed two distinct transgenic mouse models to study the impact of SRF on cardiac microRNA expression and microRNA biogenesis. Cardiac-specific overexpression of SRF (SRF-Tg led to altered expression of a number of microRNAs. Interestingly, downregulation of miR-1, miR-133a and upregulation of miR-21 occurred by 7 days of age in these mice, long before the onset of cardiac hypertrophy, suggesting that SRF overexpression impacted the expression of microRNAs which contribute to cardiac hypertrophy. Reducing cardiac SRF level using the antisense-SRF transgenic approach (Anti-SRF-Tg resulted in the expression of miR-1, miR-133a and miR-21 in the opposite direction. Furthermore, we observed that SRF regulates microRNA biogenesis, specifically the transcription of pri-microRNA, thereby affecting the mature microRNA level. The mir-21 promoter sequence is conserved among mouse, rat and human; one SRF binding site was found to be in the mir-21 proximal promoter region of all three species. The mir-21 gene is regulated by SRF and its cofactors, including myocardin and p49/Strap. Our study demonstrates that the downregulation of miR-1, miR-133a, and upregulation of miR-21 can be reversed by one single upstream regulator, SRF. These results may help to develop novel therapeutic interventions targeting microRNA biogenesis.

  6. Environmental factors shaping cultured free-living amoebae and their associated bacterial community within drinking water network.

    Science.gov (United States)

    Delafont, Vincent; Bouchon, Didier; Héchard, Yann; Moulin, Laurent

    2016-09-01

    Free-living amoebae (FLA) constitute an important part of eukaryotic populations colonising drinking water networks. However, little is known about the factors influencing their ecology in such environments. Because of their status as reservoir of potentially pathogenic bacteria, understanding environmental factors impacting FLA populations and their associated bacterial community is crucial. Through sampling of a large drinking water network, the diversity of cultivable FLA and their bacterial community were investigated by an amplicon sequencing approach, and their correlation with physicochemical parameters was studied. While FLA ubiquitously colonised the water network all year long, significant changes in population composition were observed. These changes were partially explained by several environmental parameters, namely water origin, temperature, pH and chlorine concentration. The characterisation of FLA associated bacterial community reflected a diverse but rather stable consortium composed of nearly 1400 OTUs. The definition of a core community highlighted the predominance of only few genera, majorly dominated by Pseudomonas and Stenotrophomonas. Co-occurrence analysis also showed significant patterns of FLA-bacteria association, and allowed uncovering potentially new FLA - bacteria interactions. From our knowledge, this study is the first that combines a large sampling scheme with high-throughput identification of FLA together with associated bacteria, along with their influencing environmental parameters. Our results demonstrate the importance of physicochemical parameters in the ecology of FLA and their bacterial community in water networks. PMID:27219048

  7. A Bioinformatics Analysis Reveals a Group of MocR Bacterial Transcriptional Regulators Linked to a Family of Genes Coding for Membrane Proteins

    Directory of Open Access Journals (Sweden)

    Teresa Milano

    2016-01-01

    Full Text Available The MocR bacterial transcriptional regulators are characterized by an N-terminal domain, 60 residues long on average, possessing the winged-helix-turn-helix (wHTH architecture responsible for DNA recognition and binding, linked to a large C-terminal domain (350 residues on average that is homologous to fold type-I pyridoxal 5′-phosphate (PLP dependent enzymes like aspartate aminotransferase (AAT. These regulators are involved in the expression of genes taking part in several metabolic pathways directly or indirectly connected to PLP chemistry, many of which are still uncharacterized. A bioinformatics analysis is here reported that studied the features of a distinct group of MocR regulators predicted to be functionally linked to a family of homologous genes coding for integral membrane proteins of unknown function. This group occurs mainly in the Actinobacteria and Gammaproteobacteria phyla. An analysis of the multiple sequence alignments of their wHTH and AAT domains suggested the presence of specificity-determining positions (SDPs. Mapping of SDPs onto a homology model of the AAT domain hinted at possible structural/functional roles in effector recognition. Likewise, SDPs in wHTH domain suggested the basis of specificity of Transcription Factor Binding Site recognition. The results reported represent a framework for rational design of experiments and for bioinformatics analysis of other MocR subgroups.

  8. Risk factors for bacterial vaginosis in pregnancy: a population-based study on Danish women

    DEFF Research Database (Denmark)

    Thorsen, Poul; Vogel, Ida; Molsted, Kirsten;

    2006-01-01

    .5, homogenous discharge, clue cells, and positive amine test). Data were collected from three questionnaires completed during the second and third trimesters and correlated with the diagnosis of bacterial vaginosis. Crude and adjusted relative risks (reproductive, medical, behavioral, sexual, and...

  9. A Laboratory Assessment of Factors That Affect Bacterial Adhesion to Contact Lenses

    Directory of Open Access Journals (Sweden)

    Debarun Dutta

    2013-11-01

    Full Text Available Adhesion of pathogenic microbes, particularly bacteria, to contact lenses is implicated in contact lens related microbial adverse events. Various in vitro conditions such as type of bacteria, the size of initial inoculum, contact lens material, nutritional content of media, and incubation period can influence bacterial adhesion to contact lenses and the current study investigated the effect of these conditions on bacterial adhesion to contact lenses. There was no significant difference in numbers of bacteria that adhered to hydrogel etafilcon A or silicone hydrogel senofilcon A contact lenses. Pseudomonas aeruginosa adhered in higher numbers compared to Staphylococcus aureus. Within a genera/species, adhesion of different bacterial strains did not differ appreciably. The size of initial inoculum, nutritional content of media, and incubation period played significant roles in bacterial adhesion to lenses. A set of in vitro assay conditions to help standardize adhesion between studies have been recommended.

  10. A Laboratory Assessment of Factors That Affect Bacterial Adhesion to Contact Lenses

    OpenAIRE

    Debarun Dutta; Mark DP Willcox

    2013-01-01

    Adhesion of pathogenic microbes, particularly bacteria, to contact lenses is implicated in contact lens related microbial adverse events. Various in vitro conditions such as type of bacteria, the size of initial inoculum, contact lens material, nutritional content of media, and incubation period can influence bacterial adhesion to contact lenses and the current study investigated the effect of these conditions on bacterial adhesion to contact lenses. There was no significant difference in num...

  11. Bacterial profiles of saliva in relation to diet, lifestyle factors, and socioeconomic status

    OpenAIRE

    Belstrøm, Daniel; Holmstrup, Palle; Nielsen, Claus H.; Kirkby, Nikolai; Twetman, Svante; Heitmann, Berit L.; Klepac-Ceraj, Vanja; Paster, Bruce J; Fiehn, Nils-Erik

    2014-01-01

    Background and objective: The bacterial profile of saliva is composed of bacteria from different oral surfaces. The objective of this study was to determine whether different diet intake, lifestyle, or socioeconomic status is associated with characteristic bacterial saliva profiles.Design: Stimulated saliva samples from 292 participants with low levels of dental caries and periodontitis, enrolled in the Danish Health Examination Survey (DANHES), were analyzed for the presence of approximately...

  12. Effect of Environmental Factors and Influence of Rumen and Hindgut Biogeography on Bacterial Communities in Steers▿

    OpenAIRE

    Romero-Pérez, Gustavo A.; Ominski, Kim H.; McAllister, Tim A.; Denis O Krause

    2010-01-01

    Feces from cattle production are considered important sources of bacterial contamination of food and the environment. Little is known about the combined effects of arctic temperatures and fodder tannins on rumen and hindgut bacterial populations. Individual rumen liquor and rectal fecal samples from donor steers fed either alfalfa silage or sainfoin (Onobrychis viciifolia Scop.) silage and water ad libitum were collected weekly on the first three sampling days and fortnightly afterwards. The ...

  13. Prevalence of bacterial vaginosis and its risk factors in HIV/AIDSpatients with abnormal vaginal discharge

    Institute of Scientific and Technical Information of China (English)

    Samuel Nwadioha; Daniel Egah; Edmond Banwat; Julie Egesie; Ifeanyi Onwuezobe

    2011-01-01

    Objective:To determine the prevalence of bacterial vaginosis in theHIV/AIDS patients of primary health care clinics in Jos Plateau state, Nigeria.Methods: Female genital swabs were collected from primary health care centers, Jos and analyzed by microscopy, culture,etc. in Jos University Teaching Hospital from December2006 to December2007. Data on epidemiologic indices were collected, using structured interviewer-administered questionnaires.Results:The incidence of bacterial vaginosis in the study was 28%(n=196/700). Among theHIV/AIDS group, the bacterial vaginosis incidence was36% (n=126/350), while in the control (non-HIV patients) group, the rate was20% (70/350) with a statistically significant difference at 95 percent confidence level(P<0.05) .HIV/AIDSand non-HIV (control) patients contributed64% (n=126/196) and36%(n=70/196), respectively. The risks to bacterial vaginosis included vaginal douching with disinfectant/detergent constituted(60%), poor use of condom40%, a median age of26years, and a median number of3 sex partners per week.Conclusions: There was a significant statistical difference in prevalence of bacterial vaginosis between theHIV/AIDS group and non-HIV(control) group of patients in the study. Risk behaviors that promote the incidence of bacterial vaginosis should be especially paid attention.

  14. Crystal structure of the full-length bacterial selenocysteine-specific elongation factor SelB.

    Science.gov (United States)

    Itoh, Yuzuru; Sekine, Shun-Ichi; Yokoyama, Shigeyuki

    2015-10-15

    Selenocysteine (Sec), the 21(st) amino acid in translation, uses its specific tRNA (tRNA(Sec)) to recognize the UGA codon. The Sec-specific elongation factor SelB brings the selenocysteinyl-tRNA(Sec) (Sec-tRNA(Sec)) to the ribosome, dependent on both an in-frame UGA and a Sec-insertion sequence (SECIS) in the mRNA. The bacterial SelB binds mRNA through its C-terminal region, for which crystal structures have been reported. In this study, we determined the crystal structure of the full-length SelB from the bacterium Aquifex aeolicus, in complex with a GTP analog, at 3.2-Å resolution. SelB consists of three EF-Tu-like domains (D1-3), followed by four winged-helix domains (WHD1-4). The spacer region, connecting the N- and C-terminal halves, fixes the position of WHD1 relative to D3. The binding site for the Sec moiety of Sec-tRNA(Sec) is located on the interface between D1 and D2, where a cysteine molecule from the crystallization solution is coordinated by Arg residues, which may mimic Sec binding. The Sec-binding site is smaller and more exposed than the corresponding site of EF-Tu. Complex models of Sec-tRNA(Sec), SECIS RNA, and the 70S ribosome suggest that the unique secondary structure of tRNA(Sec) allows SelB to specifically recognize tRNA(Sec) and characteristically place it at the ribosomal A-site. PMID:26304550

  15. Alternative splicing regulation during C. elegans development: splicing factors as regulated targets.

    Directory of Open Access Journals (Sweden)

    Sergio Barberan-Soler

    2008-02-01

    Full Text Available Alternative splicing generates protein diversity and allows for post-transcriptional gene regulation. Estimates suggest that 10% of the genes in Caenorhabditis elegans undergo alternative splicing. We constructed a splicing-sensitive microarray to detect alternative splicing for 352 cassette exons and tested for changes in alternative splicing of these genes during development. We found that the microarray data predicted that 62/352 (approximately 18% of the alternative splicing events studied show a strong change in the relative levels of the spliced isoforms (>4-fold during development. Confirmation of the microarray data by RT-PCR was obtained for 70% of randomly selected genes tested. Among the genes with the most developmentally regulated alternatively splicing was the hnRNP F/H splicing factor homolog, W02D3.11 - now named hrpf-1. For the cassette exon of hrpf-1, the inclusion isoform comprises 65% of hrpf-1 steady state messages in embryos but only 0.1% in the first larval stage. This dramatic change in the alternative splicing of an alternative splicing factor suggests a complex cascade of splicing regulation during development. We analyzed splicing in embryos from a strain with a mutation in the splicing factor sym-2, another hnRNP F/H homolog. We found that approximately half of the genes with large alternative splicing changes between the embryo and L1 stages are regulated by sym-2 in embryos. An analysis of the role of nonsense-mediated decay in regulating steady-state alternative mRNA isoforms was performed. We found that 8% of the 352 events studied have alternative isoforms whose relative steady-state levels in embryos change more than 4-fold in a nonsense-mediated decay mutant, including hrpf-1. Strikingly, 53% of these alternative splicing events that are affected by NMD in our experiment are not obvious substrates for NMD based on the presence of premature termination codons. This suggests that the targeting of splicing factors

  16. Fibroblast Growth Factor 21 Mediates Glycemic Regulation by Hepatic JNK

    Directory of Open Access Journals (Sweden)

    Santiago Vernia

    2016-03-01

    Full Text Available The cJun NH2-terminal kinase (JNK-signaling pathway is implicated in metabolic syndrome, including dysregulated blood glucose concentration and insulin resistance. Fibroblast growth factor 21 (FGF21 is a target of the hepatic JNK-signaling pathway and may contribute to the regulation of glycemia. To test the role of FGF21, we established mice with selective ablation of the Fgf21 gene in hepatocytes. FGF21 deficiency in the liver caused marked loss of FGF21 protein circulating in the blood. Moreover, the protective effects of hepatic JNK deficiency to suppress metabolic syndrome in high-fat diet-fed mice were not observed in mice with hepatocyte-specific FGF21 deficiency, including reduced blood glucose concentration and reduced intolerance to glucose and insulin. Furthermore, we show that JNK contributes to the regulation of hepatic FGF21 expression during fasting/feeding cycles. These data demonstrate that the hepatokine FGF21 is a key mediator of JNK-regulated metabolic syndrome.

  17. Histone Chaperone HIRA in Regulation of Transcription Factor RUNX1.

    Science.gov (United States)

    Majumder, Aditi; Syed, Khaja Mohieddin; Joseph, Sunu; Scambler, Peter J; Dutta, Debasree

    2015-05-22

    RUNX1 (Runt-related transcription factor 1) is indispensable for the generation of hemogenic endothelium. However, the regulation of RUNX1 during this developmental process is poorly understood. We investigated the role of the histone chaperone HIRA (histone cell cycle regulation-defective homolog A) from this perspective and report that HIRA significantly contributes toward the regulation of RUNX1 in the transition of differentiating mouse embryonic stem cells from hemogenic to hematopoietic stage. Direct interaction of HIRA and RUNX1 activates the downstream targets of RUNX1 implicated in generation of hematopoietic stem cells. At the molecular level, HIRA-mediated incorporation of histone H3.3 variant within the Runx1 +24 mouse conserved noncoding element is essential for the expression of Runx1 during endothelial to hematopoietic transition. An inactive chromatin at the intronic enhancer of Runx1 in absence of HIRA significantly repressed the transition of cells from hemogenic to hematopoietic fate. We expect that the HIRA-RUNX1 axis might open up a novel approach in understanding leukemogenesis in future. PMID:25847244

  18. Artificial transcription factor-mediated regulation of gene expression.

    Science.gov (United States)

    van Tol, Niels; van der Zaal, Bert J

    2014-08-01

    The transcriptional regulation of endogenous genes with artificial transcription factors (TFs) can offer new tools for plant biotechnology. Three systems are available for mediating site-specific DNA recognition of artificial TFs: those based on zinc fingers, TALEs, and on the CRISPR/Cas9 technology. Artificial TFs require an effector domain that controls the frequency of transcription initiation at endogenous target genes. These effector domains can be transcriptional activators or repressors, but can also have enzymatic activities involved in chromatin remodeling or epigenetic regulation. Artificial TFs are able to regulate gene expression in trans, thus allowing them to evoke dominant mutant phenotypes. Large scale changes in transcriptional activity are induced when the DNA binding domain is deliberately designed to have lower binding specificity. This technique, known as genome interrogation, is a powerful tool for generating novel mutant phenotypes. Genome interrogation has clear mechanistic and practical advantages over activation tagging, which is the technique most closely resembling it. Most notably, genome interrogation can lead to the discovery of mutant phenotypes that are unlikely to be found when using more conventional single gene-based approaches. PMID:25017160

  19. ST2 negatively regulates TLR2 signaling, but is not required for bacterial lipoprotein-induced tolerance.

    LENUS (Irish Health Repository)

    Liu, Jinghua

    2010-05-15

    Activation of TLR signaling is critical for host innate immunity against bacterial infection. Previous studies reported that the ST2 receptor, a member of the Toll\\/IL-1 receptor superfamily, functions as a negative regulator of TLR4 signaling and maintains LPS tolerance. However, it is undetermined whether ST2 negatively regulates TLR2 signaling and furthermore, whether a TLR2 agonist, bacterial lipoprotein (BLP)-induced tolerance is dependent on ST2. In this study, we show that BLP stimulation-induced production of proinflammatory cytokines and immunocomplex formation of TLR2-MyD88 and MyD88-IL-1R-associated kinase (IRAK) were significantly enhanced in ST2-deficient macrophages compared with those in wild-type controls. Furthermore, overexpression of ST2 dose-dependently attenuated BLP-induced NF-kappaB activation, suggesting a negative regulatory role of ST2 in TLR2 signaling. A moderate but significantly attenuated production of TNF-alpha and IL-6 on a second BLP stimulation was observed in BLP-pretreated, ST2-deficient macrophages, which is associated with substantially reduced IRAK-1 protein expression and downregulated TLR2-MyD88 and MyD88-IRAK immunocomplex formation. ST2-deficient mice, when pretreated with a nonlethal dose of BLP, benefitted from an improved survival against a subsequent lethal BLP challenge, indicating BLP tolerance develops in the absence of the ST2 receptor. Taken together, our results demonstrate that ST2 acts as a negative regulator of TLR2 signaling, but is not required for BLP-induced tolerance.

  20. A new pharmacological agent (AKB-4924) stabilizes hypoxia inducible factor-1 (HIF-1) and increases skin innate defenses against bacterial infection.

    Science.gov (United States)

    Okumura, Cheryl Y M; Hollands, Andrew; Tran, Dan N; Olson, Joshua; Dahesh, Samira; von Köckritz-Blickwede, Maren; Thienphrapa, Wdee; Corle, Courtney; Jeung, Seung Nam; Kotsakis, Anna; Shalwitz, Robert A; Johnson, Randall S; Nizet, Victor

    2012-09-01

    Hypoxia inducible factor-1 (HIF-1) is a transcription factor that is a major regulator of energy homeostasis and cellular adaptation to low oxygen stress. HIF-1 is also activated in response to bacterial pathogens and supports the innate immune response of both phagocytes and keratinocytes. In this work, we show that a new pharmacological compound AKB-4924 increases HIF-1 levels and enhances the antibacterial activity of phagocytes and keratinocytes against both methicillin-sensitive and methicillin-resistant strains of Staphylococcus aureus in vitro. AKB-4924 is also effective in stimulating the killing capacity of keratinocytes against the important opportunistic skin pathogens Pseudomonas aeruginosa and Acinetobacter baumanii. The effect of AKB-4924 is mediated through the activity of host cells, as the compound exerts no direct antimicrobial activity. Administered locally as a single agent, AKB-4924 limits S. aureus proliferation and lesion formation in a mouse skin abscess model. This approach to pharmacologically boost the innate immune response via HIF-1 stabilization may serve as a useful adjunctive treatment for antibiotic-resistant bacterial infections. PMID:22371073

  1. Comparison of tryptophan biosynthetic operon regulation in different Gram-positive bacterial species.

    Science.gov (United States)

    Gutiérrez-Preciado, Ana; Yanofsky, Charles; Merino, Enrique

    2007-09-01

    The tryptophan biosynthetic operon has been widely used as a model system for studying transcription regulation. In Bacillus subtilis, the trp operon is primarily regulated by a tryptophan-activated RNA-binding protein, TRAP. Here we show that in many other Gram-positive species the trp operon is regulated differently, by tRNA(Trp) sensing by the RNA-based T-box mechanism, with T-boxes arranged in tandem. Our analyses reveal an apparent relationship between trp operon organization and the specific regulatory mechanism(s) used. PMID:17555843

  2. The role of small intestinal bacterial overgrowth, intestinal permeability, endotoxaemia, and tumour necrosis factor α in the pathogenesis of non-alcoholic steatohepatitis

    OpenAIRE

    Wigg, A.; Roberts-Thomson, I; Dymock, R; McCarthy, P.; Grose, R; CUMMINS, A

    2001-01-01

    BACKGROUND—Small intestinal bacterial overgrowth may contribute to the development of non-alcoholic steatohepatitis, perhaps by increasing intestinal permeability and promoting the absorption of endotoxin or other enteric bacterial products.
AIMS—To investigate the prevalence of small intestinal bacterial overgrowth, increased intestinal permeability, elevated endotoxin, and tumour necrosis factor α (TNF-α) levels in patients with non-alcoholic steatohepatitis and in control subjects.
PATIENT...

  3. Limited functional conservation of a global regulator among related bacterial genera: Lrp in Escherichia, Proteus and Vibrio

    Directory of Open Access Journals (Sweden)

    Martinez-Vaz Betsy M

    2008-04-01

    Full Text Available Abstract Background Bacterial genome sequences are being determined rapidly, but few species are physiologically well characterized. Predicting regulation from genome sequences usually involves extrapolation from better-studied bacteria, using the hypothesis that a conserved regulator, conserved target gene, and predicted regulator-binding site in the target promoter imply conserved regulation between the two species. However many compared organisms are ecologically and physiologically diverse, and the limits of extrapolation have not been well tested. In E. coli K-12 the leucine-responsive regulatory protein (Lrp affects expression of ~400 genes. Proteus mirabilis and Vibrio cholerae have highly-conserved lrp orthologs (98% and 92% identity to E. coli lrp. The functional equivalence of Lrp from these related species was assessed. Results Heterologous Lrp regulated gltB, livK and lrp transcriptional fusions in an E. coli background in the same general way as the native Lrp, though with significant differences in extent. Microarray analysis of these strains revealed that the heterologous Lrp proteins significantly influence only about half of the genes affected by native Lrp. In P. mirabilis, heterologous Lrp restored swarming, though with some pattern differences. P. mirabilis produced substantially more Lrp than E. coli or V. cholerae under some conditions. Lrp regulation of target gene orthologs differed among the three native hosts. Strikingly, while Lrp negatively regulates its own gene in E. coli, and was shown to do so even more strongly in P. mirabilis, Lrp appears to activate its own gene in V. cholerae. Conclusion The overall similarity of regulatory effects of the Lrp orthologs supports the use of extrapolation between related strains for general purposes. However this study also revealed intrinsic differences even between orthologous regulators sharing >90% overall identity, and 100% identity for the DNA-binding helix-turn-helix motif

  4. Heterotrophic bacterial production: Relationships to biological and abiological factors in estuarine environments

    Energy Technology Data Exchange (ETDEWEB)

    Koepfler, E.T.

    1989-01-01

    Ecotoxicological effects of creosote contamination on benthic bacterial communities in the Elizabeth River, Virginia were investigated using both structural an functional microbial parameters. Results indicated that cell specific and total heterotrophic bacterial production parameters were depressed in a dose-dependent manner with increasing sediment PAH concentrations. Toxicity effects upon production were modified by temporal trends associated with temperature as well as spatial sediment characteristics. Of the parameters employed, the tritiated thymidine production assay was found to be the most sensitive for detection of ecotoxicological effects. Bacterial abundance and production were examined during a destratification event in the lower James River, Virginia. Bacterial abundance, although significantly different between stations, did not change over the study. Bacterial production ({sup 3}H-Tdr incorporation) in surface waters was significantly less during the mixed period 187 {mu}g C{center dot}1-1{center dot} d{sup {minus}1} compared to the most stratified state (324{mu}g C{center dot}1-1{center dot} d{sup {minus}1}). Correlations between bacteria and chlorophyll were diminished during the mixed period. Total and flagellate specific grazing rates upon bacteria were reduced during the onset of destratification. Relationships between bacterial and nutrient parameters also indicated a strong influence of destratification. These results indicate that destratification changes trophic interactions within the microbial loop, which are not necessarily reflected in temporal patterns of bacterial abundance. Bacterioplankton production, and ammonium assimilation and remineralization were examined between April and August 1988 in the lower York River, Va.

  5. RNA-Mediated Reciprocal Regulation between Two Bacterial Operons Is RNase III Dependent

    OpenAIRE

    Johnson, Christopher M; Haemig, Heather H. A.; Chatterjee, Anushree; Wei-Shou, Hu; Weaver, Keith E.; Dunny, Gary M.

    2011-01-01

    Abstract In bacteria, RNAs regulate gene expression and function via several mechanisms. An RNA may pair with complementary sequences in a target RNA to impact transcription, translation, or degradation of the target. Control of conjugation of pCF10, a pheromone response plasmid of Enterococcus faecalis, is a well-characterized system that serves as a model for the regulation of gene expression in bacteria by intercellular signaling. The prgQ operon, whose products mediate conjugation, is neg...

  6. Role of granulocyte colony-stimulating factor in paclitaxel-induced intestinal barrier breakdown and bacterial translocation in rats

    Institute of Scientific and Technical Information of China (English)

    ZHANG Chi; XU Yang-guang; DUAN Xue-ning; LIU Yin-hua; ZHAO Jian-xin; XU Ling; YE Jing-ming

    2011-01-01

    Background Chemotherapy causes breakdown of the intestinal barrier, which may lead to bacterial translocation. Paclitaxel, an anti-tubulin agent, has many side effects; however, its effect on the intestinal barrier is unknown. Previous studies show that granulocyte colony-stimulating factor (G-CSF) plays an important role in modulating intestinal barrier function, but these studies are not conclusive. Here, we investigated the effects of paclitaxel on the intestinal barrier, and whether G-CSF could prevent paclitaxel-induced bacterial translocation.Methods Twenty-four male Sprague-Dawley rats were divided into three groups: control group, paclitaxel group and paclitaxel + G-CSF group. Intestinal permeability was measured by the urinary excretion rates of lactulose and mannitol administered by gavage. The mesenteric lymph nodes, spleen and liver were aseptically harvested for bacterial culture. Endotoxin levels and white blood cell (WBC) counts were measured and bacterial quantification performed using relative real-time PCR. Jejunum samples were also obtained for histological observation. Intestinal apoptosis was evaluated using a fragmented DNA assay and terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate (dUTP)-biotin nick end-labeling staining. One-way analysis of variance and Fisher's exact test were used to compare differences between groups.Results Paclitaxel induced apoptosis in 12.5% of jejunum villus cells, which was reduced to 3.8% by G-CSF treatment. Apoptosis in the control group was 0.6%. Paclitaxel treatment also resulted in villus atrophy, increased intestinal permeability and a reduction in the WBC count. G-CSF treatment resulted in increased villus height and returned WBC counts to normal levels. No bacterial translocation was detected in the control group, whereas 6/8,8/8, and 8/8 rats in the paclitaxel group were culture-positive in the liver, spleen and mesenteric lymph nodes, respectively. Bacterial translocation was

  7. Bacterial Ortholog of Mammalian Translocator Protein (TSPO) with Virulence Regulating Activity

    Science.gov (United States)

    Chapalain, Annelise; Chevalier, Sylvie; Orange, Nicole; Murillo, Laurence; Papadopoulos, Vassilios; Feuilloley, Marc G. J.

    2009-01-01

    The translocator protein (TSPO), previously designated as peripheral-type benzodiazepine receptor, is a protein mainly located in the outer mitochondrial membrane of eukaryotic cells. TSPO is implicated in major physiological functions and functionally associated with other proteins such as the voltage-dependent anionic channel, also designated as mitochondrial porin. Surprisingly, a TSPO-related protein was identified in the photosynthetic bacterium Rhodobacter sphaeroides but it was initially considered as a relict of evolution. In the present study we cloned a tspO gene in Pseudomonas fluorescens MF37, a non-photosynthetic eubacterium and we used bioinformatics tools to identify TSPO in the genome of 97 other bacteria. P. fluorescens TSPO was recognized by antibodies against mouse protein and by PK 11195, an artificial ligand of mitochondrial TSPO. As in eukaryotes, bacterial TSPO appears functionally organized as a dimer and the apparent Kd for PK 11195 is in the same range than for its eukaryotic counterpart. When P. fluorescens MF37 was treated with PK 11195 (10−5 M) adhesion to living or artificial surfaces and biofilm formation activity were increased. Conversely, the apoptotic potential of bacteria on eukaryotic cells was significantly reduced. This effect of PK11195 was abolished in a mutant of P. fluorescens MF37 deficient for its major outer membrane porin, OprF. The present results demonstrate the existence of a bacterial TSPO that shares common structural and functional characteristics with its mammalian counterpart. This protein, apparently involved in adhesion and virulence, reveals the existence of a possible new inter kingdom signalling system and suggests that the human microbiome should be involuntarily exposed to the evolutionary pressure of benzodiazepines and related molecules. This discovery also represents a promising opportunity for the development of alternative antibacterial strategies. PMID:19564920

  8. Bacterial ortholog of mammalian translocator protein (TSPO with virulence regulating activity.

    Directory of Open Access Journals (Sweden)

    Annelise Chapalain

    Full Text Available The translocator protein (TSPO, previously designated as peripheral-type benzodiazepine receptor, is a protein mainly located in the outer mitochondrial membrane of eukaryotic cells. TSPO is implicated in major physiological functions and functionally associated with other proteins such as the voltage-dependent anionic channel, also designated as mitochondrial porin. Surprisingly, a TSPO-related protein was identified in the photosynthetic bacterium Rhodobacter sphaeroides but it was initially considered as a relict of evolution. In the present study we cloned a tspO gene in Pseudomonas fluorescens MF37, a non-photosynthetic eubacterium and we used bioinformatics tools to identify TSPO in the genome of 97 other bacteria. P. fluorescens TSPO was recognized by antibodies against mouse protein and by PK 11195, an artificial ligand of mitochondrial TSPO. As in eukaryotes, bacterial TSPO appears functionally organized as a dimer and the apparent Kd for PK 11195 is in the same range than for its eukaryotic counterpart. When P. fluorescens MF37 was treated with PK 11195 (10(-5 M adhesion to living or artificial surfaces and biofilm formation activity were increased. Conversely, the apoptotic potential of bacteria on eukaryotic cells was significantly reduced. This effect of PK11195 was abolished in a mutant of P. fluorescens MF37 deficient for its major outer membrane porin, OprF. The present results demonstrate the existence of a bacterial TSPO that shares common structural and functional characteristics with its mammalian counterpart. This protein, apparently involved in adhesion and virulence, reveals the existence of a possible new inter kingdom signalling system and suggests that the human microbiome should be involuntarily exposed to the evolutionary pressure of benzodiazepines and related molecules. This discovery also represents a promising opportunity for the development of alternative antibacterial strategies.

  9. Bacterial ortholog of mammalian translocator protein (TSPO) with virulence regulating activity.

    Science.gov (United States)

    Chapalain, Annelise; Chevalier, Sylvie; Orange, Nicole; Murillo, Laurence; Papadopoulos, Vassilios; Feuilloley, Marc G J

    2009-01-01

    The translocator protein (TSPO), previously designated as peripheral-type benzodiazepine receptor, is a protein mainly located in the outer mitochondrial membrane of eukaryotic cells. TSPO is implicated in major physiological functions and functionally associated with other proteins such as the voltage-dependent anionic channel, also designated as mitochondrial porin. Surprisingly, a TSPO-related protein was identified in the photosynthetic bacterium Rhodobacter sphaeroides but it was initially considered as a relict of evolution. In the present study we cloned a tspO gene in Pseudomonas fluorescens MF37, a non-photosynthetic eubacterium and we used bioinformatics tools to identify TSPO in the genome of 97 other bacteria. P. fluorescens TSPO was recognized by antibodies against mouse protein and by PK 11195, an artificial ligand of mitochondrial TSPO. As in eukaryotes, bacterial TSPO appears functionally organized as a dimer and the apparent Kd for PK 11195 is in the same range than for its eukaryotic counterpart. When P. fluorescens MF37 was treated with PK 11195 (10(-5) M) adhesion to living or artificial surfaces and biofilm formation activity were increased. Conversely, the apoptotic potential of bacteria on eukaryotic cells was significantly reduced. This effect of PK11195 was abolished in a mutant of P. fluorescens MF37 deficient for its major outer membrane porin, OprF. The present results demonstrate the existence of a bacterial TSPO that shares common structural and functional characteristics with its mammalian counterpart. This protein, apparently involved in adhesion and virulence, reveals the existence of a possible new inter kingdom signalling system and suggests that the human microbiome should be involuntarily exposed to the evolutionary pressure of benzodiazepines and related molecules. This discovery also represents a promising opportunity for the development of alternative antibacterial strategies. PMID:19564920

  10. Spatial isolation and environmental factors drive distinct bacterial and archaeal communities in different types of petroleum reservoirs in China

    Science.gov (United States)

    Gao, Peike; Tian, Huimei; Wang, Yansen; Li, Yanshu; Li, Yan; Xie, Jinxia; Zeng, Bing; Zhou, Jiefang; Li, Guoqiang; Ma, Ting

    2016-02-01

    To investigate the spatial distribution of microbial communities and their drivers in petroleum reservoir environments, we performed pyrosequencing of microbial partial 16S rRNA, derived from 20 geographically separated water-flooding reservoirs, and two reservoirs that had not been flooded, in China. The results indicated that distinct underground microbial communities inhabited the different reservoirs. Compared with the bacteria, archaeal alpha-diversity was not strongly correlated with the environmental variables. The variation of the bacterial and archaeal community compositions was affected synthetically, by the mining patterns, spatial isolation, reservoir temperature, salinity and pH of the formation brine. The environmental factors explained 64.22% and 78.26% of the total variance for the bacterial and archaeal communities, respectively. Despite the diverse community compositions, shared populations (48 bacterial and 18 archaeal genera) were found and were dominant in most of the oilfields. Potential indigenous microorganisms, including Carboxydibrachium, Thermosinus, and Neptunomonas, were only detected in a reservoir that had not been flooded with water. This study indicates that: 1) the environmental variation drives distinct microbial communities in different reservoirs; 2) compared with the archaea, the bacterial communities were highly heterogeneous within and among the reservoirs; and 3) despite the community variation, some microorganisms are dominant in multiple petroleum reservoirs.

  11. Silkworm ferritin 1 heavy chain homolog is involved in defense against bacterial infection through regulation of haemolymph iron homeostasis.

    Science.gov (United States)

    Otho, Sohail Ahmed; Chen, Kangkang; Zhang, Yongdong; Wang, Peng; Lu, Zhiqiang

    2016-02-01

    Iron functions as a nutrient and a potential toxin in all organisms. It plays a key role in the interaction between microbes and their hosts as well. Microbial infection disrupts iron homeostasis in the host; meanwhile the host endeavors to keep the homeostasis through iron transport and storage. Transferrins and ferritins are the major iron-binding proteins that affect iron distribution in insects. In this study, we investigated a possible involvement of Bombyx mori ferritin 1 (BmFer1) heavy chain homolog in the defense against bacterial infection in the silkworm larvae. The BmFer1 mRNA abundance was up-regulated in hemocytes, but not in fat body, after Pseudomonas aeruginosa or Staphylococcus aureus infection. The infection resulted in elevated iron levels in the hemolymph. Injection of recombinant BmFer1 protein into hemocoel reduced the plasma iron level after infection, limited the bacterial growth in the hemolymph, and resulted in a lower mortality caused by infection. Our study indicated that B. mori ferritin-1 may restrict iron access of the invading bacteria to block their growth as a defense strategy. PMID:26522340

  12. A non-coding RNA promotes bacterial persistence and decreases virulence by regulating a regulator in Staphylococcus aureus.

    Directory of Open Access Journals (Sweden)

    Cédric Romilly

    2014-03-01

    Full Text Available Staphylococcus aureus produces a high number of RNAs for which the functions are poorly understood. Several non-coding RNAs carry a C-rich sequence suggesting that they regulate mRNAs at the post-transcriptional level. We demonstrate that the Sigma B-dependent RsaA RNA represses the synthesis of the global transcriptional regulator MgrA by forming an imperfect duplex with the Shine and Dalgarno sequence and a loop-loop interaction within the coding region of the target mRNA. These two recognition sites are required for translation repression. Consequently, RsaA causes enhanced production of biofilm and a decreased synthesis of capsule formation in several strain backgrounds. These phenotypes led to a decreased protection of S. aureus against opsonophagocytic killing by polymorphonuclear leukocytes compared to the mutant strains lacking RsaA. Mice animal models showed that RsaA attenuates the severity of acute systemic infections and enhances chronic catheter infection. RsaA takes part in a regulatory network that contributes to the complex interactions of S. aureus with the host immune system to moderate invasiveness and favour chronic infections. It is the first example of a conserved small RNA in S. aureus functioning as a virulence suppressor of acute infections. Because S. aureus is essentially a human commensal, we propose that RsaA has been positively selected through evolution to support commensalism and saprophytic interactions with the host.

  13. Co-transcriptomic Analysis by RNA Sequencing to Simultaneously Measure Regulated Gene Expression in Host and Bacterial Pathogen

    KAUST Repository

    Ravasi, Timothy

    2016-01-24

    Intramacrophage pathogens subvert antimicrobial defence pathways using various mechanisms, including the targeting of host TLR-mediated transcriptional responses. Conversely, TLR-inducible host defence mechanisms subject intramacrophage pathogens to stress, thus altering pathogen gene expression programs. Important biological insights can thus be gained through the analysis of gene expression changes in both the host and the pathogen during an infection. Traditionally, research methods have involved the use of qPCR, microarrays and/or RNA sequencing to identify transcriptional changes in either the host or the pathogen. Here we describe the application of RNA sequencing using samples obtained from in vitro infection assays to simultaneously quantify both host and bacterial pathogen gene expression changes, as well as general approaches that can be undertaken to interpret the RNA sequencing data that is generated. These methods can be used to provide insights into host TLR-regulated transcriptional responses to microbial challenge, as well as pathogen subversion mechanisms against such responses.

  14. Regulation of DMBT1 via NOD2 and TLR4 in intestinal epithelial cells modulates bacterial recognition and invasion

    DEFF Research Database (Denmark)

    Rosenstiel, Philip; Sina, Christian; End, Caroline;

    2007-01-01

    -kappaB activation and cytokine secretion in vitro. Thus, DMBT1 may play an important role in the first line of mucosal defense conferring immune exclusion of bacterial cell wall components. Dysregulated intestinal DMBT1 expression due to mutations in the NOD2/CARD15 gene may be part of the complex pathophysiology......Mucosal epithelial cell layers are constantly exposed to a complex resident microflora. Deleted in malignant brain tumors 1 (DMBT1) belongs to the group of secreted scavenger receptor cysteine-rich proteins and is considered to be involved in host defense by pathogen binding. This report describes...... intracellular pathogen receptor NOD2 via NF-kappaB activation. DMBT1 is strongly up-regulated in the inflamed intestinal mucosa of Crohn's disease patients with wild-type, but not with mutant NOD2. We show that DMBT1 inhibits cytoinvasion of Salmonella enterica and LPS- and muramyl dipeptide-induced NF...

  15. Structure of Thermotoga maritima TM0439: implications for the mechanism of bacterial GntR transcription regulators with Zn2+-binding FCD domains

    International Nuclear Information System (INIS)

    Here, the crystal structure of TM0439, a GntR regulator with an FCD domain found in the Thermotoga maritima genome, is described. The GntR superfamily of dimeric transcription factors, with more than 6200 members encoded in bacterial genomes, are characterized by N-terminal winged-helix DNA-binding domains and diverse C-terminal regulatory domains which provide a basis for the classification of the constituent families. The largest of these families, FadR, contains nearly 3000 proteins with all-α-helical regulatory domains classified into two related Pfam families: FadR-C and FCD. Only two crystal structures of FadR-family members, those of Escherichia coli FadR protein and LldR from Corynebacterium glutamicum, have been described to date in the literature. Here, the crystal structure of TM0439, a GntR regulator with an FCD domain found in the Thermotoga maritima genome, is described. The FCD domain is similar to that of the LldR regulator and contains a buried metal-binding site. Using atomic absorption spectroscopy and Trp fluorescence, it is shown that the recombinant protein contains bound Ni2+ ions but that it is able to bind Zn2+ with Kd < 70 nM. It is concluded that Zn2+ is the likely physiological metal and that it may perform either structural or regulatory roles or both. Finally, the TM0439 structure is compared with two other FadR-family structures recently deposited by structural genomics consortia. The results call for a revision in the classification of the FadR family of transcription factors

  16. Structure of Thermotoga maritima TM0439: implications for the mechanism of bacterial GntR transcription regulators with Zn{sup 2+}-binding FCD domains

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, Meiying; Cooper, David R. [Integrated Center for Structure-Function Innovation, Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, VA 22908-0736 (United States); Grossoehme, Nickolas E. [Department of Chemistry, Indiana University, Bloomington, Indiana 47405-7102 (United States); Yu, Minmin [Physical Biosciences Division, Lawrence Berkeley National Laboratory, MS4R0230, Berkeley, CA 94720 (United States); Hung, Li-Wei [Physical Biosciences Division, Lawrence Berkeley National Laboratory, MS4R0230, Berkeley, CA 94720 (United States); Physics Division, MS D454, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Cieslik, Marcin; Derewenda, Urszula [Integrated Center for Structure-Function Innovation, Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, VA 22908-0736 (United States); Lesley, Scott A. [The Scripps Research Institute, North Torrey Pines Road, La Jolla, CA 92037 (United States); Genomics Institute of the Novartis Research Foundation, 10675 John Jay Hopkins Drive, San Diego, CA 92121 (United States); Wilson, Ian A. [The Scripps Research Institute, North Torrey Pines Road, La Jolla, CA 92037 (United States); Giedroc, David P. [Department of Chemistry, Indiana University, Bloomington, Indiana 47405-7102 (United States); Derewenda, Zygmunt S., E-mail: zsd4n@virginia.edu [Integrated Center for Structure-Function Innovation, Department of Molecular Physiology and Biological Physics, University of Virginia, Charlottesville, VA 22908-0736 (United States)

    2009-04-01

    Here, the crystal structure of TM0439, a GntR regulator with an FCD domain found in the Thermotoga maritima genome, is described. The GntR superfamily of dimeric transcription factors, with more than 6200 members encoded in bacterial genomes, are characterized by N-terminal winged-helix DNA-binding domains and diverse C-terminal regulatory domains which provide a basis for the classification of the constituent families. The largest of these families, FadR, contains nearly 3000 proteins with all-α-helical regulatory domains classified into two related Pfam families: FadR-C and FCD. Only two crystal structures of FadR-family members, those of Escherichia coli FadR protein and LldR from Corynebacterium glutamicum, have been described to date in the literature. Here, the crystal structure of TM0439, a GntR regulator with an FCD domain found in the Thermotoga maritima genome, is described. The FCD domain is similar to that of the LldR regulator and contains a buried metal-binding site. Using atomic absorption spectroscopy and Trp fluorescence, it is shown that the recombinant protein contains bound Ni{sup 2+} ions but that it is able to bind Zn{sup 2+} with K{sub d} < 70 nM. It is concluded that Zn{sup 2+} is the likely physiological metal and that it may perform either structural or regulatory roles or both. Finally, the TM0439 structure is compared with two other FadR-family structures recently deposited by structural genomics consortia. The results call for a revision in the classification of the FadR family of transcription factors.

  17. Certain methodical aspects of hygienic regulation of hazardous factors

    International Nuclear Information System (INIS)

    The problem of hygienic regulation of hazardous radiation and chemical factors is considered. Differences in reliability of some standards for radioactive and chemical substances are determined in experiments on animals (mices, rats). The differences were established for 60Co, sup(89, 90)Sr, 210Pb, 210Po, 226Ra and for 7 chemical substances (corrosive sublimate, lead, methyl mercury, chlorine compounds, strontium, hexamethylenediamine, beryllium). Maximum permissible concentrations of radionuclides are shown to be superfluously over estimated; standards for toxic chemical substances are not strictly substantiated that is dangerous for human beings and environmental objects. Necessity of unique methodological and methodical approaches to hygienic standardization on the base of cost-benefit analysis is emphasized

  18. Ets factors regulate the polycystic kidney disease-1 promoter

    International Nuclear Information System (INIS)

    The Ets family of transcription factors consists of a group of highly conserved sequence-specific DNA binding proteins that functionally cooperate with other transcription factors to regulate a number of diverse cellular processes including proliferation, differentiation, and apoptosis. We have analyzed a 3.3 kb 5'-upstream region of the human PKD1 promoter, using transient transfection in HEK293T cells and Drosophila SL2 cells, to demonstrate that the PKD1 promoter is a target of Ets family transcription factors. Our studies showed that PKD1 promoter-luciferase reporter gene expression is downregulated by cotransfected Fli-1 and is upregulated by cotransfected Ets-1. Using deletion constructs, we demonstrated that the sequences responding to Fli-1 and Ets-1 lie within the -200 to +33 bp proximal promoter. This region was found to contain two putative Ets response elements (EREs): an upstream (Ets-A) sequence 5'-CGGAA-3' (-181 to -185) and a downstream (Ets-B) sequence 5'-CGGAT-3' (-129 to -133). Site-directed mutagenesis indicated that both EREs are functional. A Fli-1 DNA binding domain mutant construct (W321R), which is incapable of binding DNA, was unable to inhibit basal promoter activity. In contrast, a Fli-1 DNA binding domain truncation mutant construct, which only contains the DNA binding domain and lacks the transactivation domain, was able to inhibit. These results suggest that the effect of Fli-1 is through direct binding to these EREs. Direct binding of Fli-1 and Ets-1 to the Ets-A and Ets-B sites was supported by electrophoretic mobility shift assays. Lastly, competition between Fli-1 and Ets-1 for the two EREs was demonstrated by showing that increasing amounts of Ets-1 could overcome Fli-1 repression of promoter activity. Taken together, these experiments define the proximal PKD1 promoter region as a potential target of Ets family transcription factors

  19. miR-200a-3p regulates TLR1 expression in bacterial challenged miiuy croaker.

    Science.gov (United States)

    Wang, Yanjin; Xu, Guoliang; Han, Jingjing; Xu, Tianjun

    2016-10-01

    MicroRNAs (miRNAs) are highly conserved, small non-coding RNAs which post-transcriptionally regulate various biological processes by repressing mRNA translation or degradating mRNA. It has been demonstrated that miRNAs play crucial roles in regulating the immune system. In this study, we explored the potential roles of miR-200a-3p in regulating TLR signaling pathway in miiuy croaker. Bioinformatics analysis showed that miiuy croaker TLR1 (mmiTLR1) was a putative target of miR-200a-3p. Negative expression profiles in spleen of Vibrio anguillarum challenged miiuy croaker and in lipopolysaccharide (LPS) stimulated miiuy croaker leukocytes further validated the prediction. Luciferase reporter assays showed that the dual-luciferase reporter fused to the 3'UTR of wild type mmiTLR1 cotransfected with miR-200a-3p mimics exhibited a reduction in luciferase activity compared with the controls. All of the present data provide direct evidence that miR-200a-3p is involved in TLR1 expression modulation in miiuy croaker, which will offer a basis for better understanding of miRNA regulation in fish TLR signaling pathways. PMID:27288848

  20. MiRNA-Based Regulation of Hemostatic Factors through Hepatic Nuclear Factor-4 Alpha

    Science.gov (United States)

    Salloum-Asfar, Salam; Arroyo, Ana B.; Teruel-Montoya, Raúl; García-Barberá, Nuria; Roldán, Vanessa; Vicente, Vicente; Martínez, Constantino; González-Conejero, Rocío

    2016-01-01

    MiRNAs have been reported as CIS-acting elements of several hemostatic factors, however, their mechanism as TRANS-acting elements mediated by a transcription factor is little known and could have important effects. HNF4α has a direct and important role in the regulation of multiple hepatic coagulation genes. Previous in vitro studies have demonstrated that miR-24-3p and miR-34a-5p regulate HNF4A expression. Here we aimed to investigate the molecular mechanisms of miR-24 and miR-34a on coagulation through HNF4A. Transfections with miR-24 and miR-34a in HepG2 cells decreased not only HNF4A but also F10, F12, SERPINC1, PROS1, PROC, and PROZ transcripts levels. Positive and significant correlations were observed between levels of HNF4A and several hemostatic factors (F5, F8, F9, F11, F12, SERPINC1, PROC, and PROS1) in human liver samples (N = 104). However, miR-24 and miR-34a levels of the low (10th) and high (90th) percentiles of those liver samples were inversely correlated with HNF4A and almost all hemostatic factors expression levels. These outcomes suggest that miR-24 and miR-34a might be two indirect elements of regulation of several hemostatic factors. Additionally, variations in miRNA expression profiles could justify, at least in part, changes in HNF4A expression levels and its downstream targets of coagulation. PMID:27135744

  1. Vascular Endothelial Growth Factor A Regulates the Secretion of Different Angiogenic Factors in Lung Cancer Cells.

    Science.gov (United States)

    Frezzetti, Daniela; Gallo, Marianna; Roma, Cristin; D'Alessio, Amelia; Maiello, Monica R; Bevilacqua, Simona; Normanno, Nicola; De Luca, Antonella

    2016-07-01

    Vascular endothelial growth factor A (VEGFA) is one of the main mediators of angiogenesis in non-small cell lung cancer (NSCLC). Recently, it has been described an autocrine feed-forward loop in NSCLC cells in which tumor-derived VEGFA promoted the secretion of VEGFA itself, amplifying the proangiogenic signal. In order to investigate the role of VEGFA in lung cancer progression, we assessed the effects of recombinant VEGFA on proliferation, migration, and secretion of other angiogenic factors in A549, H1975, and HCC827 NSCLC cell lines. We found that VEGFA did not affect NSCLC cell proliferation and migration. On the other hand, we demonstrated that VEGFA not only produced a strong and persistent increase of VEGFA itself but also significantly induced the secretion of a variety of angiogenic factors, including follistatin (FST), hepatocyte growth factor (HGF), angiopoietin-2 (ANGPT2), granulocyte-colony stimulating factor (G-CSF), interleukin (IL)-8, leptin (LEP), platelet/endothelial cell adhesion molecule 1 (PECAM-1), and platelet-derived growth factor bb (PDGF-BB). PI3K/AKT, RAS/ERK, and STAT3 signalling pathways were found to mediate the effects of VEGFA in NSCLC cell lines. We also observed that VEGFA regulation mainly occurred at post-transcriptional level and that NSCLC cells expressed different isoforms of VEGFA. Collectively, our data suggested that VEGFA contributes to lung cancer progression by inducing a network of angiogenic factors, which might offer potential for therapeutic intervention. PMID:26542886

  2. The role of T cell subsets and cytokines in the regulation of intracellular bacterial infection

    Directory of Open Access Journals (Sweden)

    Oliveira S.C.

    1998-01-01

    Full Text Available Cellular immune responses are a critical part of the host's defense against intracellular bacterial infections. Immunity to Brucella abortus crucially depends on antigen-specific T cell-mediated activation of macrophages, which are the major effectors of cell-mediated killing of this organism. T lymphocytes that proliferate in response to B. abortus were characterized for phenotype and cytokine activity. Human, murine, and bovine T lymphocytes exhibited a type 1 cytokine profile, suggesting an analogous immune response in these different hosts. In vivo protection afforded by a particular cell type is dependent on the antigen presented and the mechanism of antigen presentation. Studies using MHC class I and class II knockout mice infected with B. abortus have demonstrated that protective immunity to brucellosis is especially dependent on CD8+ T cells. To target MHC class I presentation we transfected ex vivo a murine macrophage cell line with B. abortus genes and adoptively transferred them to BALB/c mice. These transgenic macrophage clones induced partial protection in mice against experimental brucellosis. Knowing the cells required for protection, vaccines can be designed to activate the protective T cell subset. Lastly, as a new strategy for priming a specific class I-restricted T cell response in vivo, we used genetic immunization by particle bombardment-mediated gene transfer

  3. Regulation of energy metabolism by the extracytoplasmic function (ECF) s factors of Arcobacter butzleri

    Science.gov (United States)

    The extracytoplasmic function (ECF) s factors are fundamental for bacterial adaptation to distinct environments and for survival under different stress conditions. The emerging pathogen Arcobacter butzleri possesses seven putative pairs of s/anti-s factors belonging to the ECF family. Here, we repor...

  4. [Regulation of osteoclastogenesis by osteocytes through growth differentiation factor-15].

    Science.gov (United States)

    Hinoi, Eiichi

    2014-01-01

    Osteocytes are the most abundant cells in bone. However, little attention has been paid to their role in bone remodeling. In this study, osteoclast differentiation was significantly enhanced by conditioned media derived from cultures of osteocytic MLO-Y4 cells that were cultured under hypoxic conditions. Using microarray analysis, we identified growth differentiation factor-15 (GDF15) as a pivotal factor secreted from osteocytes under hypoxia. Indeed, treatment with recombinant GDF15 markedly increased osteoclast differentiation in vitro. Further to investigate the importance of GDF15 in vivo, we used a hypoxic murine model that involved ligation of the right femoral artery. The volume of cancellous bone in the proximal tibia of the ligated limb was significantly reduced, together with a significant increase in osteoclast-related parameters. Addition of anti-GDF15 antibody prevented bone loss and osteoclastic activation in the tibiae of mice that had undergone femoral artery ligation. These results suggest that GDF15, which is secreted from osteocytes under hypoxia during bone remodeling, may be a positive regulator of osteoclastic differentiation. The in vivo usefulness of the anti-GDF15 antibody might provide insights for the development of novel therapeutics for bone disorders related to hypoxia or ischemic insults. PMID:25452236

  5. The plant pathogenic fungus Gaeumannomyces graminis var. tritici improves bacterial growth and triggers early gene regulations in the biocontrol strain Pseudomonas fluorescens Pf29Arp.

    Science.gov (United States)

    Barret, M; Frey-Klett, P; Boutin, M; Guillerm-Erckelboudt, A-Y; Martin, F; Guillot, L; Sarniguet, A

    2009-01-01

    In soil, some antagonistic rhizobacteria contribute to reduce root diseases caused by phytopathogenic fungi. Direct modes of action of these bacteria have been largely explored; however, commensal interaction also takes place between these microorganisms and little is known about the influence of filamentous fungi on bacteria. An in vitro confrontation bioassay between the pathogenic fungus Gaeumannomyces graminis var. tritici (Ggt) and the biocontrol bacterial strain Pseudomonas fluorescens Pf29Arp was set up to analyse bacterial transcriptional changes induced by the fungal mycelium at three time-points of the interaction before cell contact and up until contact. For this, a Pf29Arp shotgun DNA microarray was constructed. Specifity of Ggt effect was assessed in comparison with one of two other filamentous fungi, Laccaria bicolor and Magnaporthe grisea. During a commensal interaction, Ggt increased the growth rate of Pf29Arp. Before contact, Ggt induced bacterial genes involved in mycelium colonization. At contact, genes encoding protein of stress response and a patatin-like protein were up-regulated. Among all the bacterial genes identified, xseB was specifically up-regulated at contact by Ggt but down-regulated by the other fungi. Data showed that the bacterium sensed the presence of the fungus early, but the main gene alteration occurred during bacterial-fungal cell contact. PMID:19121038

  6. Characterization of the Rel2-regulated transcriptome and proteome of Anopheles stephensi identifies new anti-Plasmodium factors.

    Science.gov (United States)

    Pike, Andrew; Vadlamani, Alekhya; Sandiford, Simone L; Gacita, Anthony; Dimopoulos, George

    2014-09-01

    Mosquitoes possess an innate immune system that is capable of limiting infection by a variety of pathogens, including the Plasmodium spp. parasites responsible for human malaria. The Anopheles immune deficiency (IMD) innate immune signaling pathway confers resistance to Plasmodium falciparum. While some previously identified Anopheles anti-Plasmodium effectors are regulated through signaling by Rel2, the transcription factor of the IMD pathway, many components of this defense system remain uncharacterized. To begin to better understand the regulation of immune effector proteins by the IMD pathway, we used oligonucleotide microarrays and iTRAQ to analyze differences in mRNA and protein expression, respectively, between transgenic Anopheles stephensi mosquitoes exhibiting blood meal-inducible overexpression of an active recombinant Rel2 and their wild-type conspecifics. Numerous genes were differentially regulated at both the mRNA and protein levels following induction of Rel2. While multiple immune genes were up-regulated, a majority of the differentially expressed genes have no known immune function in mosquitoes. Selected up-regulated genes from multiple functional categories were tested for both anti-Plasmodium and anti-bacterial action using RNA interference (RNAi). Based on our experimental findings, we conclude that increased expression of the IMD immune pathway-controlled transcription factor Rel2 affects the expression of numerous genes with diverse functions, suggesting a broader physiological impact of immune activation and possible functional versatility of Rel2. Our study has also identified multiple novel genes implicated in anti-Plasmodium defense. PMID:24998399

  7. NEW EMBO MEMBER’S REVIEW: Viral and bacterial proteins regulating apoptosis at the mitochondrial level

    OpenAIRE

    Boya, Patricia; Roques, Bernard,; Kroemer, Guido

    2001-01-01

    Mitochondrial membrane permeabilization (MMP) is a critical step of several apoptotic pathways. Some infectious intracellular pathogens can regulate (induce or inhibit) apoptosis of their host cells at the mitochondrial level, by targeting proteins to mitochondrial membranes that either induce or inhibit MMP. Pathogen-encoded mitochondrion-targeted proteins may or may not show amino acid sequence homology to Bcl-2-like proteins. Among the Bcl-2-unrelated, mitochondrion-targeted proteins, seve...

  8. Mucosal Immune Regulation in Intestinal Disease. The role of bacterial products, food components and drugs

    OpenAIRE

    Bol-Schoenmakers, M

    2009-01-01

    The challenge of the mucosal gut associated immune system is to remain unresponsive to food products and commensal microbiota, while mounting an appropriate immune response towards pathogens. This implicates the necessity of tight immune regulation within the gut associated lymphoid tissue (GALT). Imbalance between tolerance and immunity (e.g. intestinal homeostasis) contributes to the pathogenesis of intestinal diseases like inflammatory bowel disease (IBD) and food allergies. The first part...

  9. SLAM is a microbial sensor that regulates bacterial phagosome functions in macrophages

    OpenAIRE

    Berger, Scott B.; Romero, Xavier; Ma, Chunyan; WANG, GUOXING; Faubion, William A.; Liao, Gongxian; Compeer, Ewoud; Keszei, Marton; Rameh, Lucia; Wang, Ninghai; Boes, Marianne; Regueiro, Jose R.; Reinecker, Hans-Christian; Terhorst, Cox

    2010-01-01

    Phagocytosis is a pivotal process by which macrophages eliminate microorganisms after recognition by pathogen sensors. Here we unexpectedly found that the self ligand and cell surface receptor SLAM functioned not only as a costimulatory molecule but also as a microbial sensor that controlled the killing of Gram-negative bacteria by macrophages. SLAM regulated activity of the NADPH oxidase NOX2 complex and phagolysosomal maturation after entering the phagosome, following interaction with the b...

  10. Regulation of genes coding for enzyme constituents of the bacterial phosphotransferase system.

    OpenAIRE

    Rephaeli, A W; Saier, M H

    1980-01-01

    Regulation of the synthesis of the proteins of the phosphoenolpyruvate:sugar phosphotransferase system was systematically studied in wild-type and mutant strains of Salmonella typhimurium and Escherichia coli. The results suggest that enzyme I and HPr as well as the glucose-specific and the mannose-specific enzymes II are synthesized by a mechanism which depends on (i) cyclic adenosine monophosphate and its receptor protein; (ii) extracellular inducer; (iii) the sugar-specific enzyme II compl...

  11. Propionibacterium acnes CAMP factor and host acid sphingomyelinase contribute to bacterial virulence: potential targets for inflammatory acne treatment.

    Directory of Open Access Journals (Sweden)

    Teruaki Nakatsuji

    Full Text Available BACKGROUND: In the progression of acne vulgaris, the disruption of follicular epithelia by an over-growth of Propionibacterium acnes (P. acnes permits the bacteria to spread and become in contact with various skin and immune cells. METHODOLOGY/PRINCIPAL FINDINGS: We have demonstrated in the present study that the Christie, Atkins, Munch-Peterson (CAMP factor of P. acnes is a secretory protein with co-hemolytic activity with sphingomyelinase that can confer cytotoxicity to HaCaT keratinocytes and RAW264.7 macrophages. The CAMP factor from bacteria and acid sphingomyelinase (ASMase from the host cells were simultaneously present in the culture supernatant only when the cells were co-cultured with P. acnes. Either anti-CAMP factor serum or desipramine, a selective ASMase inhibitor, significantly abrogated the P. acnes-induced cell death of HaCaT and RAW264.7 cells. Intradermal injection of ICR mouse ears with live P. acnes induced considerable ear inflammation, macrophage infiltration, and an increase in cellular soluble ASMase. Suppression of ASMase by systemic treatment with desipramine significantly reduced inflammatory reaction induced by intradermal injection with P. acnes, suggesting the contribution of host ASMase in P. acnes-induced inflammatory reaction in vivo. Vaccination of mice with CAMP factor elicited a protective immunity against P. acnes-induced ear inflammation, indicating the involvement of CAMP factor in P. acnes-induced inflammation. Most notably, suppression of both bacterial CAMP factor and host ASMase using vaccination and specific antibody injection, respectively, cooperatively alleviated P. acnes-induced inflammation. CONCLUSIONS/SIGNIFICANCE: These findings envision a novel infectious mechanism by which P. acnes CAMP factor may hijack host ASMase to amplify bacterial virulence to degrade and invade host cells. This work has identified both CAMP factor and ASMase as potential molecular targets for the development of drugs

  12. Predisposing factors for positive D-Xylose breath test for evaluation of small intestinal bacterial overgrowth: A retrospective study of 932 patients

    OpenAIRE

    Schatz, Richard A; Zhang, Qing; Lodhia, Nilesh; Shuster, Jonathan; Phillip P Toskes; Moshiree, Baharak

    2015-01-01

    AIM: To investigate, in the largest cohort to date, patient characteristics and associated risk factors for developing small intestinal bacterial overgrowth (SIBO) using the D-Xylose breath test (XBT).

  13. From tyrosine to melanin: Signaling pathways and factors regulating melanogenesis.

    Science.gov (United States)

    Rzepka, Zuzanna; Buszman, Ewa; Beberok, Artur; Wrześniok, Dorota

    2016-01-01

    Melanins are natural pigments of skin, hair and eyes and can be classified into two main types: brown to black eumelanin and yellow to reddish-brown pheomelanin. Biosynthesis of melanins takes place in melanosomes, which are specialized cytoplasmic organelles of melanocytes - dendritic cells located in the basal layer of the epidermis, uveal tract of the eye, hair follicles, as well as in the inner ear, central nervous system and heart. Melanogenesis is a multistep process and begins with the conversion of amino acid L-tyrosine to DOPAquinone. The addition of cysteine or glutathione to DOPAquinone leads to the intermediates formation, followed by subsequent transformations and polymerization to the final product, pheomelanin. In the absence of thiol compounds DOPAquinone undergoes an intramolecular cyclization and oxidation to form DOPAchrome, which is then converted to 5,6-dihydroksyindole (DHI) or 5,6-dihydroxyindole-2-carboxylic acid (DHICA). Eumelanin is formed by polymerization of DHI and DHICA and their quinones. Regulation of melanogenesis is achieved by physical and biochemical factors. The article presents the intracellular signaling pathways: cAMP/PKA/CREB/MITF cascade, MAP kinases cascade, PLC/DAG/PKCβ cascade and NO/cGMP/PKG cascade, which are involved in the regulation of expression and activity of the melanogenesis-related proteins by ultraviolet radiation and endogenous agents (cytokines, hormones). Activity of the key melanogenic enzyme, tyrosinase, is also affected by pH and temperature. Many pharmacologically active substances are able to inhibit or stimulate melanin biosynthesis, as evidenced by in vitro studies on cultured pigment cells. PMID:27356601

  14. Structural Basis of Response Regulator Inhibition by a Bacterial Anti-Activator Protein

    OpenAIRE

    Melinda D Baker; Neiditch, Matthew B.

    2011-01-01

    The complex interplay between the response regulator ComA, the anti-activator RapF, and the signaling peptide PhrF controls competence development in Bacillus subtilis. More specifically, ComA drives the expression of genetic competence genes, while RapF inhibits the interaction of ComA with its target promoters. The signaling peptide PhrF accumulates at high cell density and upregulates genetic competence by antagonizing the interaction of RapF and ComA. How RapF functions mechanistically to...

  15. An alternative strategy for bacterial ribosome synthesis: Bacillus subtilis rRNA transcription regulation

    Czech Academy of Sciences Publication Activity Database

    Krásný, Libor; Gourse, Richard. L.

    2004-01-01

    Roč. 23, č. 22 (2004), s. 4473-4483. ISSN 0261-4189 Grant ostatní: National Institutes of Health(US) RO1 GM37048 Institutional research plan: CEZ:AV0Z5052915 Keywords : B. subtilis , GTP concentrations, rRNA transcription Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 10.492, year: 2004

  16. Vascular Endothelial Growth Factor And Soluble Adhesion Molecules As A Diagnostic Markers For Spontaneous Bacterial Peritonitis In Cirrhotic Liver Disease

    Directory of Open Access Journals (Sweden)

    Hamdia Ezzat Ahmed, (2Ahmed Dorrah,

    2006-03-01

    Full Text Available Spontaneous bacterial peritonitis (SBP is a frequent and severe complication in cirrhotic patients with ascites that usually results in renal failure and death despite the efficacy of the current antibiotic therapy. The aim of this study was determine serum and ascitic fluid of soluble-L selectin (s-L Selectin, intracellular adhesion molecule-1 (ICAM-1, Vascular cell adhesion molecule-1 (VCAM-1 and vascular endothelial growth factor (VEGF in cirrhotic patients, and to search for a relationship between them and SBP. This study was performed on 30 cirrhotic patients with SBP. Their ages ranged (from 38-55 years with mean of (32 + 5.5, 30 cirrhotic patients with non-infected ascites; their ages ranged (from 30-52 years with mean of (35 + 6.5. This group considered as cirrhotic control group and 20 healthy control subjects their ages ranged (from 28-55 years with mean of (30 + 7.5. Serum and ascitic fluid of adhesion molecules as well as VEGF levels were significantly higher in cirrhotic patients with SBP as well as cirrhotic patients with non-infected ascites as compared to healthy control group. There were significant increase in serum and ascitic fluid level of leukocyte, PMN and ICAM-1 in SBP as compared to cirrhotic with non-infected ascites. There was non-significant decrease in serum and AF level of VEGF in cirrhotic control group as compared to SBP group. The ascitic fluid PMN and s-L Selectin were higher in culture positive SBP patients particularly in those with gram positive isolates, where these are non-significant increase in serum and ascitic fluid level of VEGF in culture positive SBP than culture negative cases. Positive correlation was found between serum and ascitic fluid level of ICAM-1 in SBP and non-infected cirrhotic group. Also, positive correlation was found between VEGF levels in serum ascetic fluid levels in both cirrhotic groups (SBP and non-infected cirrhotic group. These data suggest that: Significant elevated level of

  17. A sophisticated network of signaling pathways regulates stomatal defenses to bacterial pathogens.

    Science.gov (United States)

    Arnaud, Dominique; Hwang, Ildoo

    2015-04-01

    Guard cells are specialized cells forming stomatal pores at the leaf surface for gas exchanges between the plant and the atmosphere. Stomata have been shown to play an important role in plant defense as a part of the innate immune response. Plants actively close their stomata upon contact with microbes, thereby preventing pathogen entry into the leaves and the subsequent colonization of host tissues. In this review, we present current knowledge of molecular mechanisms and signaling pathways implicated in stomatal defenses, with particular emphasis on plant-bacteria interactions. Stomatal defense responses begin from the perception of pathogen-associated molecular patterns (PAMPs) and activate a signaling cascade involving the production of secondary messengers such as reactive oxygen species, nitric oxide, and calcium for the regulation of plasma membrane ion channels. The analyses on downstream molecular mechanisms implicated in PAMP-triggered stomatal closure have revealed extensive interplays among the components regulating hormonal signaling pathways. We also discuss the strategies deployed by pathogenic bacteria to counteract stomatal immunity through the example of the phytotoxin coronatine. PMID:25661059

  18. Regulation of vascular endothelial growth factor on the expression of fracture healing-related factors

    Institute of Scientific and Technical Information of China (English)

    CHU Tong-wei; WANG Zheng-guo; ZHU Pei-fang

    2007-01-01

    Objective: To study the effect of vascular endothelial growth factor (VEGF) and anti-VEGF on the expression of fracture healing-related factors and observe pathological changes at fractured sites.Methods: Fracture models were established in 105 New Zealand white rabbits and they were randomly divided into control group, VEGF group and anti-VEGF group.The relevant factors expression at fractured sites was assayed and pathological changes were observed in decalcified samples at 8, 24, 72 hours and 1,3,5,8 weeks after fracture.Results: After application of VGEF, the expression of BMP appeared earlier and expression time lasted longer.On the contrary, anti-VEGF completely inhibited the expression of BMP. The fractured sites were filled with fibrous callus, cartilaginous callus and bony callus at the 3rd week and woven bone was constructed at the 5th week.Fracture healing was accomplished at the 8th week in VEGF group. In anti-VEGF polyclonal antibody group,cellular necrosis increased at early period. Continuous focal necrosis was seen in the fractured sites from the 1st week to 5th week. Vascularization reduced obviously at the 3rd week.Conclusions: Fracture healing is a result of mutual regulation and coordination among many factors. VEGF may be an important factor in fracture healing.

  19. A mixed incoherent feed-forward loop contributes to the regulation of bacterial photosynthesis genes

    OpenAIRE

    Mank, Nils N.; Berghoff, Bork A.; Klug, Gabriele

    2013-01-01

    Living cells use a variety of regulatory network motifs for accurate gene expression in response to changes in their environment or during differentiation processes. In Rhodobacter sphaeroides, a complex regulatory network controls expression of photosynthesis genes to guarantee optimal energy supply on one hand and to avoid photooxidative stress on the other hand. Recently, we identified a mixed incoherent feed-forward loop comprising the transcription factor PrrA, the sRNA PcrZ and photosyn...

  20. Laboratory testing protocol to identify critical factors in bacterial compliance monitoring.

    Science.gov (United States)

    Abbaszadegan, M; Ghatpande, P; Brereton, J; Alum, A; Narasimhan, R

    2003-01-01

    This research focused on providing guidelines for water utilities on the collection and handling of routine bacteriological samples and in developing scientifically-based approaches in selecting the most representative sampling locations. A laboratory-scale pilot distribution system was designed comprising two parallel loops, one using unlined cast-iron pipe and one using PVC pipe. Each loop contained six sampling ports, including (1) a distribution main dead end faucet, (2) one long (5.5 m; 18 feet) and (3) one short (0.3 m; 1 foot) household copper service line with threaded hose-bibb taps, (4) one hose-bibb with welded faucet, (5) one dedicated sampling port (modeled after a manufacturer's specifications) and (6) one laboratory-style (PVC) stop-cock sampling port. Residual chlorine concentrations were maintained at 0, 0.5, 1.5 and 2.0 mg/L stages during the course of the experiment. Bacterial samples were collected from the different sampling ports and assayed by membrane filtration and/or spread plate. Nutrient and R2A agars were used for heterotrophic plate counts (HPC), m-Endo agar for total coliform (TC) counts and Chromocult agar for injured bacterial analyses. Several methods of sample collection were tested using various combinations of flushing and tap disinfection, including "first flush" (no flushing, without tap disinfection), flushing only, tap disinfection only (using alcohol or hypochlorite solution) and flushing coupled with tap disinfection. The results indicated that the bacterial counts in samples drawn from dead ends were not significantly different from counts in samples from the other sample port configurations. First flush samples consistently produced the highest bacterial count results. Bacterial counts in samples from the long household copper service line were typically three orders of magnitude higher than in samples from the other sample ports. Thus, there is evidence that long copper household service connections may be unsuitable

  1. Crystal structure of Thermotoga maritima TM0439: implications for the mechanism of bacterial GntR transcription regulators with Zn2+-binding FCD domains

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, Meiying; Cooper, David; Grossoehmerb, Nickolas; Yu, Minmin; Hung, Li-Wei; Cieslik, Murcin; Derewendaro, Urszula; Lesley, Scott; Wilson, Ian; Giedrocb, David; Derewenda, Zygmunt

    2009-06-06

    The GntR superfamily of dimeric transcription factors, with more than 6200 members encoded in bacterial genomes, are characterized by N-terminal winged helix (WH) DNA-binding domains and diverse C-terminal, regulatory domains, which provide a basis for the classification of the constituent families. The largest of these families, FadR, contains nearly 3000 proteins with all a-helical regulatory domains classified into two related Pfam families: FadR{_}C and FCD. Only two crystal structures of the FadR family members, i.e. the E. coli FadR protein and the LldR from C. glutamicum, have been described to date in literature. Here we describe the crystal structure of TM0439, a GntR regulator with an FCD domain, found in the Thermotoga maritima genome. The FCD domain is similar to that of the LldR regulator, and contains a buried metal binding site. Using atomic absorption spectroscopy and Trp fluorescence, we show that the recombinant protein contains bound Ni{sup 2+} ions, but it is able to bind Zn{sup 2+} with K{sub D} < 70 nM . We conclude that Zn{sup 2+} is the likely physiological metal, where it may perform either or both structural and regulatory roles. Finally, we compare the TM0439 structure to two other FadR family structures recently deposited by Structural Genomics consortia. The results call for a revision in the classification of the FadR family of transcription factors.

  2. Mutual regulation causes co-entrainment between a synthetic oscillator and the bacterial cell cycle.

    Science.gov (United States)

    Dies, Marta; Galera-Laporta, Leticia; Garcia-Ojalvo, Jordi

    2016-04-18

    The correct functioning of cells requires the orchestration of multiple cellular processes, many of which are inherently dynamical. The conditions under which these dynamical processes entrain each other remain unclear. Here we use synthetic biology to address this question in the case of concurrent cellular oscillations. Specifically, we study at the single-cell level the interaction between the cell division cycle and a robust synthetic gene oscillator in Escherichia coli. Our results suggest that cell division is able to partially entrain the synthetic oscillations under normal growth conditions, by driving the periodic replication of the genes involved in the oscillator. Coupling the synthetic oscillations back into the cell cycle via the expression of a key regulator of chromosome replication increases the synchronization between the two periodic processes. A simple computational model allows us to confirm this effect. PMID:26674636

  3. Regulation of adenovirus-mediated elafin transgene expression by bacterial lipopolysaccharide.

    Science.gov (United States)

    Simpson, A J; Cunningham, G A; Porteous, D J; Haslett, C; Sallenave, J M

    2001-07-20

    Lipopolysaccharide (LPS) is a mediator of inflammatory lung injury. Selective augmentation of host defense molecules such as elafin (an elastase inhibitor with antimicrobial activity) at the onset of pulmonary inflammation is an attractive potential therapeutic strategy. The aim of this study was to determine whether elafin expression could be induced by LPS administered after transfection with adenovirus (Ad) encoding human elafin downstream of the murine cytomegalovirus (CMV) promoter (known to be potentially responsive to LPS). In addition, we aimed to determine the effect of local elafin augmentation on neutrophil migration to the lung. LPS significantly up-regulated elafin expression from pulmonary epithelial cells transfected with Ad-elafin in vitro. In murine airways expression of human elafin was achieved using doses low enough (3 x 10(7) plaque forming units) to circumvent overt vector-induced inflammation. LPS significantly up-regulated human elafin secretion in murine airways treated with Ad-elafin [117 ng/ml in bronchoalveolar lavage fluid (BALF) after LPS administration, 5.9 ng/ml after PBS, p < 0.01)]. Over-expression of elafin significantly augmented LPS-mediated neutrophil migration into the airways in vivo (1.30 x 10(6) neutrophils in BALF after Ad-elafin/LPS treatment, 0.54 x 10(6) after Ad-lacZ/LPS (p < 0.05), 0.63 x 10(6) after PBS/LPS (p < 0.05)) and significantly enhanced human neutrophil migration in vitro. These data suggest novel functions for elafin in neutrophil migration, and that judicious selection of promoters may allow single, low-dose adenoviral administration to effect inflammation-specific expression of potentially therapeutic transgenes. PMID:11485631

  4. Expression of innate immune complement regulators on brain epithelial cells during human bacterial meningitis

    Directory of Open Access Journals (Sweden)

    Gasque Philippe

    2006-09-01

    Full Text Available Abstract Background In meningitis, the cerebrospinal fluid contains high levels of innate immune molecules (e.g. complement which are essential to ward off the infectious challenge and to promote the infiltration of phagocytes (neutrophils, monocytes. However, epithelial cells of either the ependymal layer, one of the established niche for adult neural stem cells, or of the choroid plexus may be extremely vulnerable to bystander attack by cytotoxic and cytolytic complement components. Methods In this study, we assessed the capacity of brain epithelial cells to express membrane-bound complement regulators (ie, CD35, CD46, CD55 and CD59 in vitro and in situ by immunostaining of control and meningitis human brain tissue sections. Results Double immunofluorescence experiments for ependymal cell markers (GFAP, S100, ZO-1, E-cadherin and complement regulators indicated that the human ependymal cell line model was strongly positive for CD55, CD59 compared to weak stainings for CD46 and CD35. In tissues, we found that CD55 was weakly expressed in control choroid plexus and ependyma but was abundantly expressed in meningitis. Anti-CD59 stained both epithelia in apical location while increased CD59 staining was solely demonstrated in inflamed choroid plexus. CD46 and CD35 were not detected in control tissue sections. Conversely, in meningitis, the ependyma, subependyma and choroid plexus epithelia were strongly stained for CD46 and CD35. Conclusion This study delineates for the first time the capacity of brain ependymal and epithelial cells to respond to and possibly sustain the innate complement-mediated inflammatory insult.

  5. Wnt inhibitory factor-1 regulates glioblastoma cell cycle and proliferation.

    Science.gov (United States)

    Wu, Jun; Fang, Jiasheng; Yang, Zhuanyi; Chen, Fenghua; Liu, Jingfang; Wang, Yanjin

    2012-10-01

    Wnt proteins are powerful regulators of cell proliferation and differentiation, and activation of the Wnt signalling pathway is involved in the pathogenesis of several types of human tumours. Wnt inhibitory factor-1 (WIF-1) acts as a Wnt antagonist and tumour suppressor. Previous studies have shown that reducing expression of the WIF-1 gene aberrantly activates Wnt signalling and induces the development of certain types of cancers. In the present study, we examined the expression of WIF-1 in human primary glioblastoma multiforme (GBM) tumours. Studies using semiquantitative reverse transcription-polymerase chain reaction and immunohistochemical analysis revealed that WIF-1 expression is lower in human GBM than in normal brain tissue. To clarify the role of WIF-1, we transfected U251 human glioblastoma-derived cells, which do not express WIF-1, with the pcDNA3.1-WIF1 vector to restore WIF-1 expression. The results of cell proliferation, colony formation and apoptosis assays, as well as flow cytometry, indicate that exogenous WIF-1 has no effect on U251 cell apoptosis, but does arrest cells at the G(0)/G(1) phase and inhibit cell growth. Collectively, our data suggest that WIF-1 is a potent inhibitor of GBM growth. PMID:22901505

  6. Factors affecting the regulation of pacing: current perspectives

    Directory of Open Access Journals (Sweden)

    Mauger AR

    2014-09-01

    Full Text Available Alexis R Mauger Endurance Research Group, School of Sport and Exercise Sciences, Faculty of Science, University of Kent, Chatham, UK Abstract: During prolonged dynamic and rhythmic exercise, muscular pain and discomfort arises as a result of an increased concentration of deleterious metabolites. Sensed by peripheral nociceptors and transmitted via afferent feedback to the brain, this provides important information regarding the physiological state of the muscle. These sensations ultimately contribute to what is termed "exercise-induced pain". Despite being well recognized by athletes and coaches, and suggested to be integral to exercise performance, this construct has largely escaped attention in experimental work. This perspective article highlights the current understanding of pacing in endurance performance, and the causes of exercise-induced pain. A new perspective is described, which proposes how exercise-induced pain may be a contributing factor in helping individuals to regulate their work rate during exercise and thus provides an important construct in pacing. Keywords: pain, exercise-induced pain, discomfort, exercise performance, self-paced

  7. Phosphorylation Regulates Functions of ZEB1 Transcription Factor.

    Science.gov (United States)

    Llorens, M Candelaria; Lorenzatti, Guadalupe; Cavallo, Natalia L; Vaglienti, Maria V; Perrone, Ana P; Carenbauer, Anne L; Darling, Douglas S; Cabanillas, Ana M

    2016-10-01

    ZEB1 transcription factor is important in both development and disease, including many TGFβ-induced responses, and the epithelial-to-mesenchymal transition (EMT) by which many tumors undergo metastasis. ZEB1 is differentially phosphorylated in different cell types; however the role of phosphorylation in ZEB1 activity is unknown. Luciferase reporter studies and electrophoresis mobility shift assays (EMSA) show that a decrease in phosphorylation of ZEB1 increases both DNA-binding and transcriptional repression of ZEB1 target genes. Functional analysis of ZEB1 phosphorylation site mutants near the second zinc finger domain (termed ZD2) show that increased phosphorylation (due to either PMA plus ionomycin, or IGF-1) can inhibit transcriptional repression by either a ZEB1-ZD2 domain clone, or full-length ZEB1. This approach identifies phosphosites that have a substantial effect regulating the transcriptional and DNA-binding activity of ZEB1. Immunoprecipitation with anti-ZEB1 antibodies followed by western analysis with a phospho-Threonine-Proline-specific antibody indicates that the ERK consensus site at Thr-867 is phosphorylated in ZEB1. In addition to disrupting in vitro DNA-binding measured by EMSA, IGF-1-induced MEK/ERK phosphorylation is sufficient to disrupt nuclear localization of GFP-ZEB1 fusion clones. These data suggest that phosphorylation of ZEB1 integrates TGFβ signaling with other signaling pathways such as IGF-1. J. Cell. Physiol. 231: 2205-2217, 2016. © 2016 Wiley Periodicals, Inc. PMID:26868487

  8. Cell Wall Nonlinear Elasticity and Growth Dynamics: How Do Bacterial Cells Regulate Pressure and Growth?

    Science.gov (United States)

    Deng, Yi

    In my thesis, I study intact and bulging Escherichia coli cells using atomic force microscopy to separate the contributions of the cell wall and turgor pressure to the overall cell stiffness. I find strong evidence of power--law stress--stiffening in the E. coli cell wall, with an exponent of 1.22±0.12, such that the wall is significantly stiffer in intact cells (E = 23±8 MPa and 49±20 MPa in the axial and circumferential directions) than in unpressurized sacculi. These measurements also indicate that the turgor pressure in living cells E. coli is 29±3 kPa. The nonlinearity in cell elasticity serves as a plausible mechanism to balance the mechanical protection and tension measurement sensitivity of the cell envelope. I also study the growth dynamics of the Bacillus subtilis cell wall to help understand the mechanism of the spatiotemporal order of inserting new cell wall material. High density fluorescent markers are used to label the entire cell surface to capture the morphological changes of the cell surface at sub-cellular to diffraction-limited spatial resolution and sub-minute temporal resolution. This approach reveals that rod-shaped chaining B. subtilis cells grow and twist in a highly heterogeneous fashion both spatially and temporally. Regions of high growth and twisting activity have a typical length scale of 5 μm, and last for 10-40 minutes. Motivated by the quantification of the cell wall growth dynamics, two microscopy and image analysis techniques are developed and applied to broader applications beyond resolving bacterial growth. To resolve densely distributed quantum dots, we present a fast and efficient image analysis algorithm, namely Spatial Covariance Reconstruction (SCORE) microscopy that takes into account the blinking statistics of the fluorescence emitters. We achieve sub-diffraction lateral resolution of 100 nm from 5 to 7 seconds of imaging, which is at least an order of magnitude faster than single-particle localization based methods

  9. Regulation of nod factor sulphation genes in Rhizobium tropici CIAT899.

    Science.gov (United States)

    Manyani, H; Sousa, C; Soria Díaz, M E; Gil-Serrano, A; Megías, M

    2001-06-01

    Rhizobium tropici CIAT899 is a tropical symbiont able to nodulate various legumes such as Leucaena, Phaseolus, and Macroptilium. Broad host range of this species is related to its Nod factors wide spectrum. R. tropici contains Nod factors sulphation nod genes, nodHPQ genes, which control nodulation efficiency in Leucaena. To study nodHPQ regulation, we carried out different interposon insertions in its upstream region. One of these generated interruptions, nodI mutant produced nonsulphated Nod factors suggesting a possible dependence of these genes on nodI upstream region. Moreover, analysis results of lacZ transcriptional fusions with these genes in symbiotic plasmid showed dependence of these genes on NodD protein. In order to determine nodHPQ organization, we studied the effect of interposon insertion upstream of each lacZ transcriptional fusion, and the data obtained was used to indicate that nodHPQ belong to the nodABCSUIJ operon. However, comparison between nodP::lacZ beta-galactosidase activity in the symbiotic plasmid and in the pHM500 plasmid (containing nodHPQ genes) suggested constitutive expression in free living, and flavonoid inducible expression in symbiotic conditions. Constitutive nodHPQ expression may play a role in bacterial house-keeping metabolism. On the other hand, the transference of R. tropici nodHPQ genes to other rhizobia that do not present sulphated substitutions demonstrated that NodH protein sulphotransference is specific to C6 at the reducing end. PMID:11467733

  10. Up-regulation of intestinal vascular endothelial growth factor by Afa/Dr diffusely adhering Escherichia coli.

    Directory of Open Access Journals (Sweden)

    Gaëlle Cane

    Full Text Available BACKGROUND: Angiogenesis has been recently described as a novel component of inflammatory bowel disease pathogenesis. The level of vascular endothelial growth factor (VEGF has been found increased in Crohn's disease and ulcerative colitis mucosa. To question whether a pro-inflammatory Escherichia coli could regulate the expression of VEGF in human intestinal epithelial cells, we examine the response of cultured human colonic T84 cells to infection by E. coli strain C1845 that belongs to the typical Afa/Dr diffusely adhering E. coli family (Afa/Dr DAEC. METHODOLOGY: VEGF mRNA expression was examined by Northern blotting and q-PCR. VEGF protein levels were assayed by ELISA and its bioactivity was analysed in endothelial cells. The bacterial factor involved in VEGF induction was identified using recombinant E. coli expressing Dr adhesin, purified Dr adhesin and lipopolysaccharide. The signaling pathway activated for the up-regulation of VEGF was identified using a blocking monoclonal anti-DAF antibody, Western blot analysis and specific pharmacological inhibitors. PRINCIPAL FINDINGS: C1845 bacteria induce the production of VEGF protein which is bioactive. VEGF is induced by adhering C1845 in both a time- and bacteria concentration-dependent manner. This phenomenon is not cell line dependent since we reproduced this observation in intestinal LS174, Caco2/TC7 and INT407 cells. Up-regulation of VEGF production requires: (1 the interaction of the bacterial F1845 adhesin with the brush border-associated decay accelerating factor (DAF, CD55 acting as a bacterial receptor, and (2 the activation of a Src protein kinase upstream of the activation of the Erk and Akt signaling pathways. CONCLUSIONS: Results demonstrate that a Afa/Dr DAEC strain induces an adhesin-dependent activation of DAF signaling that leads to the up-regulation of bioactive VEGF in cultured human intestinal cells. Thus, these results suggest a link between an entero-adherent, pro

  11. Bacterial enteropathogens and factors associated with seasonal episodes of gastroenteritis in Nsukka, Nigeria.

    Science.gov (United States)

    Nzeako, Basil; Okafor, Nduka

    2002-01-01

    Each year, between April and October, many children of school age and some young adults in Nsukka, Nigeria suffer from gastroenteritis. The period covers the rainy season in this part of Africa, when manured farmland occasionally is flooded. In view of the number of people suffering diarrhoea and occasionally low-grade fever, it became necessary to investigate the nature of the bacterial agents responsible. Between April and October (1996-1998), 500 loose or watery stools were collected from patients, the ages of which ranged from one month to 31 years. Stools that contained parasites were excluded from the study. Samples were cultured on 5% blood agar and 1% egg-yolk agar (both containing 10 microg/mL ampicillin), MacConkey agar, Shigella Salmonella agar and in alkaline peptone water. Bacterial growths were identified using standard bacteriological procedures. Drinking water and some fruit and vegetables prevalent during this period of the year also were cultured. Of the 500 stool samples tested, 138 (27.6%) grew a range of organisms including Aeromonas hydrophila (65 [13%]), Salmonella spp. (55 [11%]), Shigella spp. (9 [1.8%]) and enteropathogenic Escherichia coli (9 [1.8%]). Drinking water and some vegetables grew Pseudomonas aeruginosa and Enterococcus faecalis, respectively. The highest isolation rate occurred during June and July, corresponding to the period of greatest flooding of arable land. Although no enteropathogens were isolated from the fruit and vegetables examined, they contained E. faecalis--an organism found in faeces. Our findings failed to explain why 72% of the samples grew no bacterial enteropathogens. PMID:12113407

  12. Regulation of WRKY46 Transcription Factor Function by Mitogen-Activated Protein Kinases in Arabidopsis thaliana.

    Science.gov (United States)

    Sheikh, Arsheed H; Eschen-Lippold, Lennart; Pecher, Pascal; Hoehenwarter, Wolfgang; Sinha, Alok K; Scheel, Dierk; Lee, Justin

    2016-01-01

    Mitogen-activated protein kinase (MAPK) cascades are central signaling pathways activated in plants after sensing internal developmental and external stress cues. Knowledge about the downstream substrate proteins of MAPKs is still limited in plants. We screened Arabidopsis WRKY transcription factors as potential targets downstream of MAPKs, and concentrated on characterizing WRKY46 as a substrate of the MAPK, MPK3. Mass spectrometry revealed in vitro phosphorylation of WRKY46 at amino acid position S168 by MPK3. However, mutagenesis studies showed that a second phosphosite, S250, can also be phosphorylated. Elicitation with pathogen-associated molecular patterns (PAMPs), such as the bacterial flagellin-derived flg22 peptide led to in vivo destabilization of WRKY46 in Arabidopsis protoplasts. Mutation of either phosphorylation site reduced the PAMP-induced degradation of WRKY46. Furthermore, the protein for the double phosphosite mutant is expressed at higher levels compared to wild-type proteins or single phosphosite mutants. In line with its nuclear localization and predicted function as a transcriptional activator, overexpression of WRKY46 in protoplasts raised basal plant defense as reflected by the increase in promoter activity of the PAMP-responsive gene, NHL10, in a MAPK-dependent manner. Thus, MAPK-mediated regulation of WRKY46 is a mechanism to control plant defense. PMID:26870073

  13. Epidermal Growth Factor Receptor Regulates Aberrant Expression of Insulin-Like Growth Factor-Binding Protein 3

    OpenAIRE

    TAKAOKA, MUNENORI; Harada, Hideki; Andl, Claudia D; Oyama, Kenji; Naomoto, Yoshio; Dempsey, Kelly L.; Klein-Szanto, Andres J.; El-Deiry, Wafik S; GRIMBERG, ADDA; Nakagawa, Hiroshi

    2004-01-01

    Epidermal growth factor receptor (EGFR) is frequently overexpressed in esophageal carcinoma and its precursor lesions. To gain insights into how EGFR overexpression affects cellular functions in primary human esophageal cells, we performed gene expression profiling and identified insulin-like growth factor-binding protein (IGFBP)-3 as the most up-regulated gene. IGFBP-3 regulates cell proliferation through both insulin-like growth factor-dependent and independent mechanisms. We found that IGF...

  14. Transcription regulation of HYPK by Heat Shock Factor 1.

    Directory of Open Access Journals (Sweden)

    Srijit Das

    Full Text Available HYPK (Huntingtin Yeast Partner K was originally identified by yeast two-hybrid assay as an interactor of Huntingtin, the protein mutated in Huntington's disease. HYPK was characterized earlier as an intrinsically unstructured protein having chaperone-like activity in vitro and in vivo. HYPK has the ability of reducing rate of aggregate formation and subsequent toxicity caused by mutant Huntingtin. Further investigation revealed that HYPK is involved in diverse cellular processes and required for normal functioning of cells. In this study we observed that hyperthermia increases HYPK expression in human and mouse cells in culture. Expression of exogenous Heat Shock Factor 1 (HSF1, upon heat treatment could induce HYPK expression, whereas HSF1 knockdown reduced endogenous as well as heat-induced HYPK expression. Putative HSF1-binding site present in the promoter of human HYPK gene was identified and validated by reporter assay. Chromatin immunoprecipitation revealed in vivo interaction of HSF1 and RNA polymerase II with HYPK promoter sequence. Additionally, acetylation of histone H4, a known epigenetic marker of inducible HSF1 binding, was observed in response to heat shock in HYPK gene promoter. Overexpression of HYPK inhibited cells from lethal heat-induced death whereas knockdown of HYPK made the cells susceptible to lethal heat shock-induced death. Apart from elevated temperature, HYPK was also upregulated by hypoxia and proteasome inhibition, two other forms of cellular stress. We concluded that chaperone-like protein HYPK is induced by cellular stress and under transcriptional regulation of HSF1.

  15. Nasopharyngeal vs. adenoid cultures in children undergoing adenoidectomy: prevalence of bacterial pathogens, their interactions and risk factors.

    Science.gov (United States)

    Korona-Glowniak, I; Niedzielski, A; Kosikowska, U; Grzegorczyk, A; Malm, A

    2015-03-01

    Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catarrhalis and Staphylococcus aureus colonization of the adenoids and nasopharynx in 103 preschool children who underwent adenoidectomy for recurrent upper respiratory tract infections was examined. Bacterial interactions and risk factors for bacterial colonization of the nasopharynx and adenoids, separately, were analysed statistically. The prevalence of simultaneous isolation from both anatomical sites was 45·6% for S. pneumoniae, 29·1% for H. influenzae, 15·5% for M. catarrhalis and 18·4% for S. aureus. Three pathogens were significantly more frequent together from adenoid samples; nasopharyngeal swabs more often yielded a single organism, but without statistical significance. M. catarrhalis and S. aureus significantly more frequently co-existed with S. pneumoniae and H. influenzae than with each other and a positive association of S. pneumoniae and H. influenzae in adenoid samples was evident. Several differences between risk factors for nasopharyngeal and adenoid colonization by the individual pathogens were observed. We conclude that the adenoids and nasopharynx appear to differ substantially in colonization by pathogenic microbes but occurrence of H. influenzae and S. pneumoniae in the nasopharynx could be predictive of upper respiratory tract infections. PMID:25703401

  16. Biological and genetic factors regulating natural competence in a bacterial plant pathogen.

    Science.gov (United States)

    Kung, Stephanie H; Almeida, Rodrigo P P

    2014-01-01

    For naturally competent bacteria, spatially structured growth can provide an environment for enhanced horizontal gene transfer through transformation and recombination. DNA is often present in the extracellular environment, such as in the extracellular matrix of biofilms, and the lysis of a single cell can result in high local DNA concentrations. Xylella fastidiosa is a naturally competent plant pathogen that typically lives in a surface-attached state, yet previous work characterizing the competence of this organism was conducted with planktonic cells in liquid environments. Here, we show that transformation and recombination efficiencies are two to three orders of magnitude higher for cells grown on solid compared with liquid media, with maximum recombination efficiencies of about 10(-3). Cells were highly competent throughout their exponential growth phase, with no significant change in recombination efficiencies until population growth rates began to slow. Mutations in type IV pili, competency-related, and cell-cell signalling genes significantly impacted the ability of X. fastidiosa to acquire and incorporate DNA. Because X. fastidiosa is highly competent when growing in a surface-attached state, as it does within its insect vectors and host plants, recombination of naturally transformed DNA could be a significant route by which horizontal gene transfer occurs in natural environments. PMID:24149707

  17. Comparative usefulness of inflammatory markers to indicate bacterial infection-analyzed according to blood culture results and related clinical factors.

    Science.gov (United States)

    Nishikawa, Hirokazu; Shirano, Michinori; Kasamatsu, Yu; Morimura, Ayumi; Iida, Ko; Kishi, Tomomi; Goto, Tetsushi; Okamoto, Saki; Ehara, Eiji

    2016-01-01

    To assess relationships of inflammatory markers and 2 related clinical factors with blood culture results, we retrospectively investigated inpatients' blood culture and blood chemistry findings that were recorded from January to December 2014 using electronic medical records and analyzed the data of 852 subjects (426 culture-positive and 426 culture-negative). Results suggested that the risk of positive blood culture statistically increased as inflammatory marker levels and the number of related factors increased. Concerning the effectiveness of inflammatory markers, when the outcome definition was also changed for C-reactive protein (CRP), the odds ratio had a similar value, whereas when the outcome definition of blood culture positivity was used for procalcitonin (PCT), the greatest effectiveness of that was detected. Therefore, the current results suggest that PCT is more useful than CRP as an auxiliary indication of bacterial infection. PMID:26525643

  18. Predicting the pathway involved in post-translational modification of Elongation factor P in a subset of bacterial species

    Directory of Open Access Journals (Sweden)

    de Crécy-Lagard Valérie

    2010-01-01

    Full Text Available Abstract Background The bacterial elongation factor P (EF-P is strictly conserved in bacteria and essential for protein synthesis. It is homologous to the eukaryotic translation initiation factor 5A (eIF5A. A highly conserved eIF5A lysine is modified into an unusual amino acid derived from spermidine, hypusine. Hypusine is absolutely required for eIF5A's role in translation in Saccharomyces cerevisiae. The homologous lysine of EF-P is also modified to a spermidine derivative in Escherichia coli. However, the biosynthesis pathway of this modification in the bacterial EF-P is yet to be elucidated. Presentation of the Hypothesis Here we propose a potential mechanism for the post-translational modification of EF-P. By using comparative genomic methods based on physical clustering and phylogenetic pattern analysis, we identified two protein families of unknown function, encoded by yjeA and yjeK genes in E. coli, as candidates for this missing pathway. Based on the analysis of the structural and biochemical properties of both protein families, we propose two potential mechanisms for the modification of EF-P. Testing the hypothesis This hypothesis could be tested genetically by constructing a bacterial strain with a tagged efp gene. The tag would allow the purification of EF-P by affinity chromatography and the analysis of the purified protein by mass spectrometry. yjeA or yjeK could then be deleted in the efp tagged strain and the EF-P protein purified from each mutant analyzed by mass spectrometry for the presence or the absence of the modification. This hypothesis can also be tested by purifying the different components (YjeK, YjeA and EF-P and reconstituting the pathway in vitro. Implication of the hypothesis The requirement for a fully modified EF-P for protein synthesis in certain bacteria implies the presence of specific post-translational modification mechanism in these organisms. All of the 725 bacterial genomes analyzed, possess an efp gene

  19. Cytokinin response factors regulate PIN-FORMED auxin transporters

    Czech Academy of Sciences Publication Activity Database

    Šimášková, M.; O'Brien, J.A.; Khan, M.; Van Noorden, G.; Ötvös, K.; Vieten, A.; De Clercq, E.; Van Haperen, J.M.A.; Cuesta, C.; Hoyerová, Klára; Vanneste, S.; Marhavý, P.; Wabnik, K.; Van Breusegem, F.; Nowack, M.; Murphy, A.; Friml, J.; Weijers, D.; Beeckman, T.; Benková, E.

    2015-01-01

    Roč. 6, NOV (2015), s. 8717. ISSN 2041-1723 Institutional support: RVO:61389030 Keywords : ARABIDOPSIS-THALIANA * ROOT-MERISTEM * TRANSCRIPTION FACTORS Subject RIV: ED - Physiology Impact factor: 11.470, year: 2014

  20. Risk Factors and Scoring System for Predicting Bacterial Resistance to Cefepime as Used Empirically in Haematology Wards

    Directory of Open Access Journals (Sweden)

    Hicham El Maaroufi

    2015-01-01

    Full Text Available Objectives. Bacterial resistance is of growing concern in haematology wards. As the inappropriate administration of empirical antibacterial may alter survival, we studied risk factors for resistance to our usual empirical first-line antibacterial therapy, cefepime. Methods. We retrospectively studied 103 first episodes of bacteraemia recorded in our haematology department over 2.5 years. Risk factors for cefepime-resistance were identified by multivariate logistic regression with backward selection (P<0.05. A scoring system for predicting cefepime-resistance was built on independent factor, with an internal validation by the bootstrap resampling technique. Results. 38 (37% episodes were due to Gram-negative bacteria. Fifty (49% were due to bacteria resistant to cefepime. Cefepime resistance was significantly associated with a decreased survival at day 30 (P<0.05. Three risk factors were independently associated with cefepime-resistance: acute lymphoblastic leukaemia; ≥18 days since hospital admission; and receipt of any β-lactam in the last month. Patients with ≥2 of these risk factors had a probability of 86% (CI 95%, 25 to 100% to carry a cefepime-resistant strain. Conclusion. Using our scoring system should reduce the indication of very broad antibacterial regimens in the empirical, first-line treatment of febrile hematology patients in more than 80% of the cases.

  1. Possible interaction between the bacterial transcription factor ArtA and the eukaryotic RNA polymerase III promoter.

    Science.gov (United States)

    Matsutani, Sachiko

    2016-06-01

    Eukaryotic RNA polymerase III (RNAP III) transcribes tRNA genes and short interspersed elements that have internal promoters consisting of A- and B-blocks. The B-block binding subunit of the transcription initiation factor TFIIIC binds to the B-block. The mobile bacterial insertion sequence (IS) 1 contains a RNAP III promoter-like sequence, which stimulates bacterial transcription along with the bacterial ArtA protein. Here, the DNA-binding ability of ArtA was examined in vitro using a simple, newly developed method. Various DNA fragments, including RNAP III promoter fragments, were separately incubated with purified ArtA, and then loaded onto a polyacrylamide gel. Since DNAs bound by ArtA remain in the gel wells during electrophoresis, SDS was added into the wells at the electrophoresis halfway point. It was hypothesized that SDS would dissociate the DNA-ArtA complexes in the wells, and then the DNAs would begin to migrate. In fact, new bands appeared in all of the lanes at similar intensities, indicating that ArtA binds nonspecifically to DNA. Therefore, labeled wild-type RNAP III promoter fragments were incubated with either the unlabeled wild-type or mutant fragments and ArtA, and electrophoresed. The B-block(-like) sequences of IS1, a human Alu element, and an anuran tRNA gene were important for binding to ArtA. Additionally, in silico analyses revealed the presence of the RNAP III promoter-like structures in the IS1 isoforms and the IS3 family elements. These results suggest the presence of parts of the RNAP III transcription machinery in bacteria, and might imply that its prototype existed in the common ancestor. PMID:27178279

  2. Identification and characterization of transforming growth factor β-activated kinase 1 from Litopenaeus vannamei involved in anti-bacterial host defense.

    Science.gov (United States)

    Wang, Sheng; Li, Haoyang; L, Kai; Qian, Zhe; Weng, Shaoping; He, Jianguo; Li, Chaozheng

    2016-05-01

    LvTAK1, a member of transforming growth factor β-activated kinase 1 (TAK1) families, has been identified from Litopenaeus vannamei in this study. The full length of LvTAK1 is 2670 bp, including a 2277 bp open reading frame (ORF) that encoded a putative protein of 758 amino acids with a calculated molecular weight of ∼83.4 kDa LvTAK1 expression was most abundant in muscles and was up-regulated in gills after LPS, Vibrio parahaemolyticus, Staphhylococcu saureus, Poly (I:C) and WSSV challenge. Both in vivo and in vitro experiments indicated that LvTAK1 could activate the expression of several antimicrobial peptide genes (AMPs). In addition, the dsRNA-mediated knockdown of LvTAK1 enhanced the susceptibility of shrimps to Vibrio parahaemolyticus, a kind of Gram-negative bacteria. These results suggested LvTAK1 played important roles in anti-bacterial infection. CoIP and subcellular localization assay demonstrated that LvTAK1 could interact with its binding protein LvTAB2, a key component of IMD pathway. Moreover, over-expression of LvTAK1 in Drosophila S2 cell could strongly induce the promoter activity of Diptericin (Dpt), a typical AMP which is used to read out of the activation of IMD pathway. These findings suggested that LvTAK1 could function as a component of IMD pathway. Interestingly, with the over-expression of LvTAK1 in S2 cell, the promoter activity of Metchnikowin (Mtk), a main target gene of Toll/Dif pathway, was up-regulated over 30 times, suggesting that LvTAK1 may also take part in signal transduction of the Toll pathway. In conclusion, we provided some evidences that the involvement of LvTAK1 in the regulation of both Toll and IMD pathways, as well as innate immune against bacterial infection in shrimp. PMID:27033469

  3. EVALUATION OF BIOTIC AND TREATMENT FACTORS RELATING TO BACTERIAL CONTROL OF ZEBRA MUSSELS

    International Nuclear Information System (INIS)

    Testing over the last quarter has indicated the following regarding control of zebra mussels with bacterium Pseudomonas fluorescens strain CL0145A: (1) the concentration of bacteria suspended in water is directly correlated with mussel kill; (2) the ratio of bacterial mass per mussel, if too low, could limit mussel kill; a treatment must be done at a high enough ratio so that mussels do not deplete all the suspended bacteria before the end of the desired exposure period; (3) bacteria appear to lose almost all their toxicity after suspension for 24 hr in highly oxygenated water; (4) in a recirculating pipe system, the same percentage mussel kill will be achieved irrespective of whether all the bacteria are applied at once or divided up and applied intermittently in smaller quantities over a 10-hr period. Since this is the fourth quarterly report, a summation of all test results over the last twelve months is provided as a table in this report. The table includes the above-mentioned fourth-quarter results

  4. C/EBP beta regulation of the tumor necrosis factor alpha gene.

    OpenAIRE

    Pope, R. M.; Leutz, A; Ness, S A

    1994-01-01

    Activated macrophages contribute to chronic inflammation by the secretion of cytokines and proteinases. Tumor necrosis factor alpha (TNF alpha) is particularly important in this process because of its ability to regulate other inflammatory mediators in an autocrine and paracrine fashion. The mechanism(s) responsible for the cell type-specific regulation of TNF alpha is not known. We present data to show that the expression of TNF alpha is regulated by the transcription factor C/EBP beta (NF-I...

  5. Factors affecting self-regulated learning in medical students: a qualitative study

    OpenAIRE

    JOUHARI, ZAHRA; HAGHANI, FARIBA; Changiz, Tahereh

    2015-01-01

    Introduction: Clinical courses are required of all medical students and means that they must develop the key skill of self-regulation during learning. The ability to self-regulate learning strategies is affected by different factors. This study determined the views of medical students on the factors affecting self-regulated learning (SRL).Method: This study uses a qualitative approach and the content analysis method. Nineteen medical students in their fourth, fifth, and sixth years of study a...

  6. [Soil texture as a regulating factor of Escherichia coli adsorption in a Rolling Pampa basin (Argentina)].

    Science.gov (United States)

    Behrends Kraemer, Filipe; Chagas, Celio I; Cosentino, Diego J; Paz, Marta; Moretton, Juan A

    2011-01-01

    Increase of bovine livestock rates in fragile areas of the Rolling Pampa entails a high risk of biological contamination. This biological contamination is regulated by edaphic variables such as texture, which control biological contaminants transport towards water bodies. In this work bacterial adsorption was correlated with individual particle sizes in 27 soils of a typical basin of the Rolling Pampa with slow centrifugation techniques. Bacterial adsorption values, using E. coli (ATCC 8739), ranged between 25.3 and 73.3% and significant correlation (R² = 0.6) was found between bacterial adsorption and clay content. This correlation was improved when particles smaller than 3 µm were considered (R² = 0.64) highlighting the capacity of very fine silt in adsorption mechanisms. Data obtained were compared with those proposed by Ling et al. (2002), finding similar slope but different intercept. This difference disappeared when a wild strain, isolated from bovine manures present in the basin, was used, since a bacterial adsorption increase of 48% was found. PMID:21731969

  7. Bacterial gastroenteritis

    Science.gov (United States)

    Infectious diarrhea - bacterial gastroenteritis; Acute gastroenteritis; Gastroenteritis - bacterial ... Bacterial gastroenteritis can affect 1 person or a group of people who all ate the same food. It is ...

  8. Auxiliary splice factor U2AF26 and transcription factor Gfi1 cooperate directly in regulating CD45 alternative splicing.

    NARCIS (Netherlands)

    Heyd, F.; Dam, G.B. ten; Moroy, T.

    2006-01-01

    By alternative splicing, different isoforms of the transmembrane tyrosine phosphatase CD45 are generated that either enhance or limit T cell receptor signaling. We report here that CD45 alternative splicing is regulated by cooperative action of the splice factor U2AF26 and the transcription factor G

  9. Ecological factors regulating growth of seaweeds in Arctic communities

    Directory of Open Access Journals (Sweden)

    Shoshina E. V.

    2016-03-01

    Full Text Available Features of seaweeds in the Arctic communities in connection with periodic and unperiodic influences of ecological factors have been analyzed. It has been shown that the existence of benthic algae biocenosis of the northern seas is mainly controlled by the primary periodic environmental factors acting as triggers that determine the direction of vegetative and generative processes, as well as contribute to the emergence of adaptive devices to extreme environmental conditions. Therefore, periodic exposure to environmental factors cause only structural changes in plant communities due to the elastic stability of fucus algae populations acquired as a result of the long process of adaptation to the northern seas conditions. Unperiodic primary factors also violate the ratio of the number by elimination and inhibit growth of certain algae age stages. However thanks to the stability of resistant the algae community can eventually restore its structural and functional organization

  10. Environmental factors affecting methane distribution and bacterial methane oxidation in the German Bight (North Sea)

    Czech Academy of Sciences Publication Activity Database

    Osudar, R.; Matoušů, Anna; Alawi, M.; Wagner, D.; Bussmann, I.

    2015-01-01

    Roč. 160, July (2015), s. 10-21. ISSN 0272-7714 R&D Projects: GA ČR(CZ) GA13-00243S Institutional support: RVO:60077344 Keywords : methanotrophy * estuary * Elbe River Subject RIV: DA - Hydrology ; Limnology Impact factor: 2.057, year: 2014

  11. Bacterial Adhesion & Blocking Bacterial Adhesion

    DEFF Research Database (Denmark)

    Vejborg, Rebecca Munk

    2008-01-01

    parameters, which influence the transition from a planktonic lifestyle to a sessile lifestyle, have been studied. Protein conditioning film formation was found to influence bacterial adhesion and subsequent biofilm formation considerable, and an aqueous extract of fish muscle tissue was shown to...... tract to the microbial flocs in waste water treatment facilities. Microbial biofilms may however also cause a wide range of industrial and medical problems, and have been implicated in a wide range of persistent infectious diseases, including implantassociated microbial infections. Bacterial adhesion is...... the first committing step in biofilm formation, and has therefore been intensely scrutinized. Much however, still remains elusive. Bacterial adhesion is a highly complex process, which is influenced by a variety of factors. In this thesis, a range of physico-chemical, molecular and environmental...

  12. Factors Influencing Self-Regulation in E-Learning 2.0: Confirmatory Factor Model

    Science.gov (United States)

    Zhao, Hong

    2016-01-01

    The importance of self-regulation in e-learning has been well noted in research. Relevant studies have shown a consistent positive correlation between learners' self-regulation and their success rate in e-learning. Increasing attention has been paid to developing learners' self-regulated abilities in e-learning. For students, what and how to learn…

  13. Abundance and Diversity of Bacterial, Archaeal, and Fungal Communities Along an Altitudinal Gradient in Alpine Forest Soils: What Are the Driving Factors?

    Science.gov (United States)

    Siles, José A; Margesin, Rosa

    2016-07-01

    Shifts in soil microbial communities over altitudinal gradients and the driving factors are poorly studied. Their elucidation is indispensable to gain a comprehensive understanding of the response of ecosystems to global climate change. Here, we investigated soil archaeal, bacterial, and fungal communities at four Alpine forest sites representing a climosequence, over an altitudinal gradient from 545 to 2000 m above sea level (asl), regarding abundance and diversity by using qPCR and Illumina sequencing, respectively. Archaeal community was dominated by Thaumarchaeota, and no significant shifts were detected in abundance or community composition with altitude. The relative bacterial abundance increased at higher altitudes, which was related to increasing levels of soil organic matter and nutrients with altitude. Shifts in bacterial richness and diversity as well as community structure (comprised basically of Proteobacteria, Acidobacteria, Actinobacteria, and Bacteroidetes) significantly correlated with several environmental and soil chemical factors, especially soil pH. The site at the lowest altitude harbored the highest bacterial richness and diversity, although richness/diversity community properties did not show a monotonic decrease along the gradient. The relative size of fungal community also increased with altitude and its composition comprised Ascomycota, Basidiomycota, and Zygomycota. Changes in fungal richness/diversity and community structure were mainly governed by pH and C/N, respectively. The variation of the predominant bacterial and fungal classes over the altitudinal gradient was the result of the environmental and soil chemical factors prevailing at each site. PMID:26961712

  14. Cytokines and growth factors which regulate bone cell function

    Science.gov (United States)

    Seino, Yoshiki

    Everybody knows that growth factors are most important in making bone. Hormones enhance bone formation from a long distance. Growth factors promote bone formation as an autocrine or paracrine factor in nearby bone. BMP-2 through BMP-8 are in the TGF-β family. BMP makes bone by enchondral ossification. In bone, IGF-II is most abundant, second, TGF-β, and third IGF-I. TGF-β enhances bone formation mainly by intramembranous ossification in vivo. TGF-β affects both cell proliferation and differentiation, however, TGF-β mainly enhances bone formation by intramembranous ossification. Interestingly, TGF-β is increased by estrogen(E 2), androgen, vitamin D, TGF-β and FGF. IGF-I and IGF-II also enhance bone formation. At present it remains unclear why IGF-I is more active in bone formation than IGF-II, although IGF-II is more abundant in bone compared to IGF-I. However, if only type I receptor signal transduction promotes bone formation, the strong activity of IGF-I in bone formation is understandable. GH, PTH and E 2 promotes IGF-I production. Recent data suggest that hormones containing vitamin D or E 2 enhance bone formation through growth factors. Therefore, growth factors are the key to clarifying the mechanism of bone formation.

  15. Role of bacterial and genetic factors in gastric cancer in Costa Rica

    Institute of Scientific and Technical Information of China (English)

    Sergio A Con; Hiroaki Takeuchi; Gil R Con-Chin; Vicky G Con-Chin; Nobufumi Yasuda; Reinaldo Con-Wong

    2009-01-01

    AIM: To evaluate several risk factors for gastric cancer (GC) in Costa Rican regions with contrasting GC incidence rate (GCIR). METHODS: According to GCIR, 191 Helicobacter pylori ( H pylori)-positive patients were classified into groups A (high GCIR, n = 101) and B (low GCIR, n = 90). Human DNA obtained from biopsy specimens was used in the determination of polymorphisms of the genes coding for interleukin (IL)-1o play a major role in GCIR variability in Costa Rica.

  16. Food safety in raw milk production: risk factors associated to bacterial DNA contamination.

    Science.gov (United States)

    Cerva, Cristine; Bremm, Carolina; Reis, Emily Marques dos; Bezerra, André Vinícius Andrade; Loiko, Márcia Regina; Cruz, Cláudio Estêvão Farias da; Cenci, Alexander; Mayer, Fabiana Quoos

    2014-06-01

    While human illness from milkborne pathogens may be linked to contamination of the product after pasteurization or improper pasteurization, such diseases are usually associated with consumption of raw milk or its by-products. Molecular biology tools were applied to investigate contamination by Listeria monocytogenes, Salmonella spp., some pathogenic strains of Escherichia coli, and Campylobacter jejuni in 548 raw milk samples from 125 dairy farms established in two regions from southern Brazil. Moreover, 15 variables were evaluated for their association with raw milk contamination levels, and the risk factors were determined by multiple regression analysis. Salmonella spp. were more frequently detected, followed by pathogenic E. coli. There was difference in contamination index between the regions, in which risk factors such as temporary cattle confinement, low milk production, low milking machine cleaning frequency, and milk storage area without tile walls were identified. The risk factors were specific to each region studied. Nevertheless, the data can be used to improve milk quality of dairy farms/herds with similar management practices. PMID:24715203

  17. An expandable, inducible hemangioblast state regulated by fibroblast growth factor.

    Science.gov (United States)

    Vereide, David T; Vickerman, Vernella; Swanson, Scott A; Chu, Li-Fang; McIntosh, Brian E; Thomson, James A

    2014-12-01

    During development, the hematopoietic and vascular lineages are thought to descend from common mesodermal progenitors called hemangioblasts. Here we identify six transcription factors, Gata2, Lmo2, Mycn, Pitx2, Sox17, and Tal1, that "trap" murine cells in a proliferative state and endow them with a hemangioblast potential. These "expandable" hemangioblasts (eHBs) are capable, once released from the control of the ectopic factors, to give rise to functional endothelial cells, multilineage hematopoietic cells, and smooth muscle cells. The eHBs can be derived from embryonic stem cells, from fetal liver cells, or poorly from fibroblasts. The eHBs reveal a central role for fibroblast growth factor, which not only promotes their expansion, but also facilitates their ability to give rise to endothelial cells and leukocytes, but not erythrocytes. This study serves as a demonstration that ephemeral progenitor states can be harnessed in vitro, enabling the creation of tractable progenitor cell lines. PMID:25458896

  18. A cell-counting factor regulating structure size in Dictyostelium

    OpenAIRE

    Brock, Debra A; Gomer, Richard H.

    1999-01-01

    Developing Dictyostelium cells form large aggregation streams that break up into groups of 0.2 × 105 to 1 × 105 cells. Each group then becomes a fruiting body. smlA cells oversecrete an unknown factor that causes aggregation streams to break up into groups of ∼5 × 103 cells and thus form very small fruiting bodies. We have purified the counting factor and find that it behaves as a complex of polypeptides with an effective molecular mass of 450 kD. One of the polypeptides is a 40-kD hydrophili...

  19. Activating transcription factor 4 regulates osteoclast differentiation in mice

    OpenAIRE

    Cao, Huiling; Yu, Shibing; Yao, Zhi; Galson, Deborah L; Jiang, Yu; Zhang, Xiaoyan; Fan, Jie; Lu, Binfeng; Guan, Youfei; Luo, Min; Lai, Yumei; Zhu, Yibei; Kurihara, Noriyoshi; Patrene, Kenneth; Roodman, G. David

    2010-01-01

    Activating transcription factor 4 (ATF4) is a critical transcription factor for osteoblast (OBL) function and bone formation; however, a direct role in osteoclasts (OCLs) has not been established. Here, we targeted expression of ATF4 to the OCL lineage using the Trap promoter or through deletion of Atf4 in mice. OCL differentiation was drastically decreased in Atf4–/– bone marrow monocyte (BMM) cultures and bones. Coculture of Atf4–/– BMMs with WT OBLs or a high concentration of RANKL failed ...

  20. Cooperative Regulation of the Activity of Factor Xa within Prothrombinase by Discrete Amino Acid Regions from Factor Va Heavy Chain†

    Science.gov (United States)

    2008-01-01

    The prothrombinase complex catalyzes the activation of prothrombin to α-thrombin. We have repetitively shown that amino acid region 695DYDY698 from the COOH terminus of the heavy chain of factor Va regulates the rate of cleavage of prothrombin at Arg271 by prothrombinase. We have also recently demonstrated that amino acid region 334DY335 is required for the optimal activity of prothrombinase. To assess the effect of these six amino acid residues on cofactor activity, we created recombinant factor Va molecules combining mutations at amino acid regions 334–335 and 695−698 as follows: factor V3K (334DY335 → KF and 695DYDY698 → KFKF), factor VKF/4A (334DY335 → KF and 695DYDY698 → AAAA), and factor V6A (334DY335 → AA and 695DYDY698 → AAAA). The recombinant factor V molecules were expressed and purified to homogeneity. Factor Va3K, factor VaK4/4A, and factor Va6A had reduced affinity for factor Xa, when compared to the affinity of the wild-type molecule (factor VaWt) for the enzyme. Prothrombinase assembled with saturating concentrations of factor Va3K had a 6-fold reduced second-order rate constant for prothrombin activation compared to the value obtained with prothrombinase assembled with factor VaWt, while prothrombinase assembled with saturating concentrations of factor VaKF/4A and factor Va6A had approximately 1.5-fold reduced second-order rate constants. Overall, the data demonstrate that amino acid region 334–335 together with amino acid region 695−698 from factor Va heavy chain are part of a cooperative mechanism within prothrombinase regulating cleavage and activation of prothrombin by factor Xa. PMID:18991406

  1. Enhancement of Methacholine-Evoked Tracheal Contraction Induced by Bacterial Lipopolysaccharides Depends on Epithelium and Tumor Necrosis Factor

    Directory of Open Access Journals (Sweden)

    T. Secher

    2012-01-01

    Full Text Available Inhaled bacterial lipopolysaccharides (LPSs induce an acute tumour necrosis factor-alpha (TNF-α- dependent inflammatory response in the murine airways mediated by Toll-like receptor 4 (TLR4 via the myeloid differentiation MyD88 adaptor protein pathway. However, the contractile response of the bronchial smooth muscle and the role of endogenous TNFα in this process have been elusive. We determined the in vivo respiratory pattern of C57BL/6 mice after intranasal LPS administration with or without the presence of increasing doses of methacholine (MCh. We found that LPS administration altered the basal and MCh-evoked respiratory pattern that peaked at 90 min and decreased thereafter in the next 48 h, reaching basal levels 7 days later. We investigated in controlled ex vivo condition the isometric contraction of isolated tracheal rings in response to MCh cholinergic stimulation. We observed that preincubation of the tracheal rings with LPS for 90 min enhanced the subsequent MCh-induced contractile response (hyperreactivity, which was prevented by prior neutralization of TNFα with a specific antibody. Furthermore, hyperreactivity induced by LPS depended on an intact epithelium, whereas hyperreactivity induced by TNFα was well maintained in the absence of epithelium. Finally, the enhanced contractile response to MCh induced by LPS when compared with control mice was not observed in tracheal rings from TLR4- or TNF- or TNF-receptor-deficient mice. We conclude that bacterial endotoxin-mediated hyperreactivity of isolated tracheal rings to MCh depends upon TLR4 integrity that signals the activation of epithelium, which release endogenous TNFα.

  2. Defense of single-factor models of population regulation

    International Nuclear Information System (INIS)

    I reject a multifactorial approach to the study of the regulation of animal populations for two reasons. First, a mechanism suggested by Chitty, that has natural selection at its base, has not been adequately tested. Second, the multifactorial model suggested by Lidicker is untestable because of its vagueness. As a middle ground, I suggest a model that has natural selection as its mechanism, but is multifacturial because it allows many parameters to be the selective agents. I particularly emphasize prediction and selective dispersal. Methods to test this model are suggested

  3. Activating transcription factor 3 regulates immune and metabolic homeostasis

    Czech Academy of Sciences Publication Activity Database

    Ryneš, J.; Donohoe, C. D.; Frommolt, P.; Brodesser, S.; Jindra, Marek; Uhlířová, M.

    2012-01-01

    Roč. 32, č. 19 (2012), s. 3949-3962. ISSN 0270-7306 R&D Projects: GA ČR(CZ) GD204/09/H058 Institutional support: RVO:60077344 Keywords : metabolic homeostasis Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 5.372, year: 2012

  4. mADP-RTs: Versatile virulence factors from bacterial pathogens of plants and mammals

    OpenAIRE

    Lennart eWirthmueller; Banfield, Mark J.

    2012-01-01

    Mono ADP-ribosyltransferases (mADP-RTs) are a family of enzymes that cleave NAD+ and covalently attach the ADP-ribosyl moiety to target proteins. mADP-RTs are well established as important virulence factors of bacteria that infect mammals. Cholera toxin, pertussis toxin and diphteria toxin are three of the best-known examples of mADP-RTs. They modify host target proteins in order to promote infection and/or killing of the host cell. Despite low sequence similarity at the primary amino acid le...

  5. GATA-4 transcription factor regulates hepatic hepcidin expression.

    Science.gov (United States)

    Island, Marie-Laure; Fatih, Nadia; Leroyer, Patricia; Brissot, Pierre; Loreal, Olivier

    2011-08-01

    Hepcidin, a hormone mainly synthesized by hepatocytes and secreted in plasma, controls iron bioavailability. Thus, by inducing the internalization of the iron exporter ferroportin, it regulates iron release from macrophages, enterocytes and hepatocytes towards plasma. Abnormal levels of hepcidin expression alter plasma iron parameters and lead to iron metabolism disorders. Understanding the mechanisms controlling hepcidin (HAMP encodes hepcidin) gene expression is therefore an important goal. We identified a potential GATA-binding site within the human hepcidin promoter. Indeed, in hepatic HepG2 cells, luciferase experiments demonstrated that mutation of this GATA-binding site impaired the hepcidin promoter transcriptional activity in basal conditions. Gel-retardation experiments showed that GATA-4 could bind to this site. Co-transfection of a GATA-4 expression vector with a hepcidin promoter reporter construct enhanced hepcidin promoter transcriptional activity. Furthermore, modulation of GATA4 mRNA expression using specific siRNAs (small interfering RNAs) down-regulated endogenous hepcidin gene expression. Finally, we found that mutation of the GATA-binding site impaired the interleukin-6 induction of hepcidin gene expression, but did not prevent the bone morphogenetic protein-6 response. In conclusion, the findings of the present study (i) indicate that GATA-4 may participate in the control of hepcidin expression, and (ii) suggest that alteration of its expression could contribute to the development of iron-related disorders. PMID:21609320

  6. Small Intestinal Bacterial Overgrowth in Patients with Irritable Bowel Syndrome: Clinical Characteristics, Psychological Factors, and Peripheral Cytokines

    Science.gov (United States)

    Chu, Hua; Fox, Mark; Zheng, Xia; Deng, Yanyong; Long, Yanqin; Huang, Zhihui; Du, Lijun; Xu, Fei; Dai, Ning

    2016-01-01

    Small intestinal bacterial overgrowth (SIBO) has been implicated in the pathogenesis of irritable bowel syndrome (IBS). Psychosocial factors and low-grade colonic mucosal immune activation have been suggested to play important roles in the pathophysiology of IBS. In total, 94 patients with IBS and 13 healthy volunteers underwent a 10 g lactulose hydrogen breath test (HBT) with concurrent 99mTc scintigraphy. All participants also completed a face-to-face questionnaire survey, including the Hospital Anxiety and Depression Scale, Life Event Stress (LES), and general information. Serum tumour necrosis factor-α, interleukin- (IL-) 6, IL-8, and IL-10 levels were measured. The 89 enrolled patients with IBS and 13 healthy controls had no differences in baseline characteristics. The prevalence of SIBO in patients with IBS was higher than that in healthy controls (39% versus 8%, resp.; p = 0.026). Patients with IBS had higher anxiety, depression, and LES scores, but anxiety, depression, and LES scores were similar between the SIBO-positive and SIBO-negative groups. Psychological disorders were not associated with SIBO in patients with IBS. The serum IL-10 level was significantly lower in SIBO-positive than SIBO-negative patients with IBS. PMID:27379166

  7. An Expandable, Inducible Hemangioblast State Regulated by Fibroblast Growth Factor

    Directory of Open Access Journals (Sweden)

    David T. Vereide

    2014-12-01

    Full Text Available During development, the hematopoietic and vascular lineages are thought to descend from common mesodermal progenitors called hemangioblasts. Here we identify six transcription factors, Gata2, Lmo2, Mycn, Pitx2, Sox17, and Tal1, that “trap” murine cells in a proliferative state and endow them with a hemangioblast potential. These “expandable” hemangioblasts (eHBs are capable, once released from the control of the ectopic factors, to give rise to functional endothelial cells, multilineage hematopoietic cells, and smooth muscle cells. The eHBs can be derived from embryonic stem cells, from fetal liver cells, or poorly from fibroblasts. The eHBs reveal a central role for fibroblast growth factor, which not only promotes their expansion, but also facilitates their ability to give rise to endothelial cells and leukocytes, but not erythrocytes. This study serves as a demonstration that ephemeral progenitor states can be harnessed in vitro, enabling the creation of tractable progenitor cell lines.

  8. Factors regulating fat oxidation in human skeletal muscle

    DEFF Research Database (Denmark)

    Kiens, Bente; Alsted, Thomas Junker; Jeppesen, Jacob

    2011-01-01

    In modern societies, oversupply of calories leads to obesity and chronic metabolic stress, which may lead to development of disease. Oversupply of calories is often associated with elevated plasma lipid concentrations and accumulation of lipids in skeletal muscle leading to decreased insulin...... sensitivity. Consequently, enhanced fat oxidation might be beneficial in counteracting lipid accumulation. Exercise is the most effective way to increase fat oxidation, because it increases metabolic rate. Lipid metabolism can also be altered by dietary manipulations. Thus, a fat rich diet leads to increased...... potential for fat oxidation by increasing the content of several of the proteins in the fat oxidative pathway. The regulation of both exercise and diet induced lipid oxidation will be discussed in this review....

  9. Differential effects of β-catenin and NF-κB interplay in the regulation of cell proliferation, inflammation and tumorigenesis in response to bacterial infection.

    Directory of Open Access Journals (Sweden)

    Parthasarathy Chandrakesan

    Full Text Available Both β-catenin and NF-κB have been implicated in our laboratory as candidate factors in driving proliferation in an in vivo model of Citrobacter rodentium (CR-induced colonic crypt hyper-proliferation and hyperplasia. Herein, we test the hypothesis that β-catenin and not necessarily NF-κB regulates colonic crypt hyperplasia or tumorigenesis in response to CR infection. When C57Bl/6 wild type (WT mice were infected with CR, sequential increases in proliferation at days 9 and 12 plateaued off at day 19 and paralleled increases in NF-κB signaling. In Tlr4(-/- (KO mice, a sequential but sustained proliferation which tapered off only marginally at day 19, was associated with TLR4-dependent and independent increases in NF-κB signaling. Similarly, increases in either activated or total β-catenin in the colonic crypts of WT mice as early as day 3 post-infection coincided with cyclinD1 and c-myc expression and associated crypt hyperplasia. In KO mice, a delayed kinetics associated predominantly with increases in non-phosphorylated (active β-catenin coincided with increases in cyclinD1, c-myc and crypt hyperplasia. Interestingly, PKCζ-catalyzed Ser-9 phosphorylation and inactivation of GSK-3β and not loss of wild type APC protein accounted for β-catenin accumulation and nuclear translocation in either strain. In vitro studies with Wnt2b and Wnt5a further validated the interplay between the Wnt/β-catenin and NF-κB pathways, respectively. When WT or KO mice were treated with nanoparticle-encapsulated siRNA to β-catenin (si-β-Cat, almost complete loss of nuclear β-catenin coincided with concomitant decreases in CD44 and crypt hyperplasia without defects in NF-κB signaling. si-β-Cat treatment to Apc(Min/+ mice attenuated CR-induced increases in β-catenin and CD44 that halted the growth of mutated crypts without affecting NF-κB signaling. The predominant β-catenin-induced crypt proliferation was further validated in a Castaneus strain (B6

  10. Divergent protein motifs direct elongation factor P-mediated translational regulation in Salmonella enterica and Escherichia coli

    DEFF Research Database (Denmark)

    Hersch, Steven J; Wang, Mengchi; Zou, S Betty;

    2013-01-01

    Elongation factor P (EF-P) is a universally conserved bacterial translation factor homologous to eukaryotic/archaeal initiation factor 5A. In Salmonella, deletion of the efp gene results in pleiotropic phenotypes, including increased susceptibility to numerous cellular stressors. Only a limited n...

  11. Unexpected versatility in bacterial riboswitches.

    Science.gov (United States)

    Mellin, J R; Cossart, Pascale

    2015-03-01

    Bacterial riboswitches are elements present in the 5'-untranslated regions (UTRs) of mRNA molecules that bind to ligands and regulate the expression of downstream genes. Riboswitches typically regulate the expression of protein-coding genes. However, mechanisms of riboswitch-mediated regulation have recently been shown to be more diverse than originally thought, with reports showing that riboswitches can regulate the expression of noncoding RNAs and control the access of proteins, such as transcription termination factor Rho and RNase E, to a nascent RNA. Riboswitches are also increasingly used in biotechnology, with advances in the engineering of synthetic riboswitches and the development of riboswitch-based sensors. In this review we address the emerging roles and mechanisms of riboswitch-mediated regulation in natura and recent progress in the development of riboswitch-based technology. PMID:25708284

  12. Aetiology and factors associated with bacterial diarrhoeal diseases amongst urban refugee children in Eastleigh, Kenya: A case control study

    Directory of Open Access Journals (Sweden)

    Waqo G. Boru

    2013-03-01

    Full Text Available Introduction: Kenya is home to over 400 000 refugees from neighbouring countries. There is scanty information about diarrhoea amongst urban refugees in Kenya.Objectives: We investigated the enteric bacteria causing diarrhoea amongst urban refugee children and described the associated factors.Method: During the period of August–December 2010, urban refugee children between the ages of two and five who attended Eastleigh County Council Health Centre were enrolled into the study. Diarrhoeal cases were compared with age-matched children with no diarrhoea (controls. Stool specimens were collected and enteric bacteria isolated. A questionnaire was administered to identify risk factors.Results: A total of 41 cases and 41 controls were enrolled in the study. The age and country of origin were similar for cases and controls. The bacterial isolation rates amongst the cases were: non-pathogenic Escherichia coli 71%, Shigella dysenteriae 2.4%, Shigella flexneri 2.4%, Salmonella paratyphi 5%. For the controls, non-pathogenic E. coli 90% and enterotoxigenic E. coli (ETEC2.4% were amongst the organisms isolated. All isolates were resistant to amoxicillin; resistance to other antibiotics varied by isolate type. Factors associated independently with diarrhoea included children not washing their hands with soap (aOR 5.9, p < 0.05, neighbour(s having diarrhoea (aOR 39.8, p < 0.05, children not exclusively breastfed for their first 6 months (aOR 7.6, p < 0.05 and children eating food cooked the previous day (aOR 23.8, p = 0.002.Conclusions: Shigella species, Salmonella species and ETEC were found to be responsible for diarrhoea amongst the urban refugee children. Measures to control and guide the use of antibiotics are critical for the prevention of antibiotic resistance. Efforts to improve personal and domestic hygiene, including educational campaigns to promote appropriate handwashing, should be encouraged.

  13. Women's Views and Experiences of the Triggers for Onset of Bacterial Vaginosis and Exacerbating Factors Associated with Recurrence.

    Directory of Open Access Journals (Sweden)

    Jade Bilardi

    Full Text Available Bacterial vaginosis (BV is the most common vaginal infection affecting women of childbearing age. While the aetiology and transmissibility of BV remain unclear, there is strong evidence to suggest an association between BV and sexual activity. This study explored women's views and experiences of the triggers for BV onset and factors associated with recurrence.A descriptive, social constructionist approach was chosen as the framework for the study. Thirty five women of varying sexual orientation who had experienced recurrent BV in the past five years took part in semi-structured interviews.The majority of women predominantly reported sexual contact triggered the onset of BV and sexual and non-sexual factors precipitated recurrence. Recurrence was most commonly referred to in terms of a 'flare-up' of symptoms. The majority of women did not think BV was a sexually transmitted infection however many reported being informed this by their clinician. Single women who attributed BV onset to sex with casual partners were most likely to display self-blame tendencies and to consider changing their future sexual behaviour. Women who have sex with women (WSW were more inclined to believe their partner was responsible for the transmission of or reinfection with BV and seek partner treatment or change their sexual practices.Findings from this study strongly suggest women believe that BV onset is associated with sexual activity, concurring with epidemiological data which increasingly suggest BV may be sexually transmitted. Exacerbating factors associated with recurrence were largely heterogeneous and may reflect the fact it is difficult to determine whether recurrence is due to persistent BV or a new infection in women. There was however evidence to suggest possible transmission and reinfection among WSW, reinforcing the need for new approaches to treatment and management strategies including male and female partner treatment trials.

  14. Source to sink transport and regulation by environmental factors

    Directory of Open Access Journals (Sweden)

    Remi eLemoine

    2013-07-01

    Full Text Available Source-to-sink transport of sugar is one of the major determinants of plant growth and relies on the efficient and controlled distribution of sucrose (and some other sugars such as raffinose and polyols across plant organs through the phloem. However, sugar transport through the phloem can be affected by many environmental factors that alter source/sink relationships. In this paper, we summarize current knowledge about the phloem transport mechanisms and review the effects of several abiotic (water and salt stress, mineral deficiency, CO2, light, temperature, air and soil pollutants and biotic (mutualistic and pathogenic microbes, viruses, aphids and parasitic plants factors. Concerning abiotic constraints, alteration of the distribution of sugar among sinks is often reported, with some sinks as roots favoured in case of mineral deficiency. Many of these constraints impair the transport function of the phloem but the exact mechanisms are far from being completely known. Phloem integrity can be disrupted (e.g. by callose deposition and under certain conditions, phloem transport is affected, earlier than photosynthesis. Photosynthesis inhibition could result from the increase in sugar concentration due to phloem transport decrease. Biotic interactions (aphids, fungi, viruses… also affect crop plant productivity. Recent breakthroughs have identified some of the sugar transporters involved in these interactions on the host and pathogen sides. The different data are discussed in relation to the phloem transport pathways. When possible, the link with current knowledge on the pathways at the molecular level will be highlighted.

  15. A review on environmental factors regulating arsenic methylation in humans

    International Nuclear Information System (INIS)

    Subjects exposed to arsenic show significant inter-individual variation in urinary patterns of arsenic metabolites but insignificant day-to-day intra-individual variation. The inter-individual variation in arsenic methylation can be partly responsible for the variation in susceptibility to arsenic toxicity. Wide inter-ethnic variation and family correlation in urinary arsenic profile suggest a genetic effect on arsenic metabolism. In this paper the environmental factors affecting arsenic metabolism are reviewed. Methylation capacity might reduce with increasing dosage of arsenic exposure. Furthermore, women, especially at pregnancy, have better methylation capacity than their men counterparts, probably due to the effect of estrogen. Children might have better methylation capacity than adults and age shows inconsistent relevance in adults. Smoking and alcohol consumption might be associated with a poorer methylation capacity. Nutritional status is important in the methylation capacity and folate may facilitate the methylation and excretion of arsenic. Besides, general health conditions and medications might influence the arsenic methylation capacity; and technical problems can cause biased estimates. The consumption of seafood, seaweed, rice and other food with high arsenic contents and the extent of cooking and arsenic-containing water used in food preparation may also interfere with the presentation of the urinary arsenic profile. Future studies are necessary to clarify the effects of the various arsenic metabolites including the trivalent methylated forms on the development of arsenic-induced human diseases with the consideration of the effects of confounding factors and the interactions with other effect modifiers

  16. THE ROLE OF BACTERIAL FACTOR AND IMMUNOLOGICAL СHANGES IN NONINFECTIOUS DISEASES OF MICROBIAL ORIGIN

    Directory of Open Access Journals (Sweden)

    Korniychuk O.P.

    2015-05-01

    Full Text Available Introduction. Today during the study of the development mechanisms of any somatic disease possible participation of the microorganism as trigger factor or its influence on the course of the disease or development of complications is considered. Microflora participation in the etiopathogenesis of noninfectious diseases allows to divide the latest into the following groups: Naturally, the first aspects of the study of the role of microorganisms in the development of noninfectious diseases are pathological processes developing in the organs and systems of the body, which are natural biotope, particularly gastrointestinal tract. The imbalance in the functioning of the macroorganism (stress, poor diet causes changes in the composition of endogenous microcenosis and therefore dysbiosis. Thus changes in the hormonal homeostasis, immunoreactivity, in the hypothalamic-adrenal system, speed of peristalsis of the intestines are observed, the overgrowth syndrome in the small intestine developes. A classic disease of a group of diseases that are accompanied by the development of erosive conditions are Helicobacter pylori - associated ulcerous disease of 12 duodenal ulcer. Diseases of the colon digestive canal can be divided into 2 groups - ulcerative colitis and tumors. Escherichia are the main representatives of facultative anaerobic microflora of the colon and are involved in the pathogenesis of both ulcerative colitis and cancer. Material and methods. A study in order to compare the inducing impact of Escherichia lipopolysaccharide isolated from patients with nonspecific ulcerative colitis (NUC, N =38, Crohn's disease (CD, N =30 and colon cancer (CC, N =38, on the humoral and cellular (cytokine links of immunity in ulcerative colitis and colon cancer. From the patients in both study groups and individuals from the control group E. coli were isolated from fecal for obtainining LPS. Synthesis induction of TNFα, IL.-8 and IL.-10 was conducted by

  17. Design of a Comprehensive Biochemistry and Molecular Biology Experiment: Phase Variation Caused by Recombinational Regulation of Bacterial Gene Expression

    Science.gov (United States)

    Sheng, Xiumei; Xu, Shungao; Lu, Renyun; Isaac, Dadzie; Zhang, Xueyi; Zhang, Haifang; Wang, Huifang; Qiao, Zheng; Huang, Xinxiang

    2014-01-01

    Scientific experiments are indispensable parts of Biochemistry and Molecular Biology. In this study, a comprehensive Biochemistry and Molecular Biology experiment about "Salmonella enterica" serovar Typhi Flagellar phase variation has been designed. It consisted of three parts, namely, inducement of bacterial Flagellar phase variation,…

  18. The Influence of Demographic Risk Factors on Children's Behavioral Regulation in Prekindergarten and Kindergarten

    Science.gov (United States)

    Wanless, Shannon B.; McClelland, Megan M.; Tominey, Shauna L.; Acock, Alan C.

    2011-01-01

    Research Findings: The present study examined the role of demographic risk factors in the development of children's behavioral regulation. We investigated whether being from a low-income family and being an English language learner (ELL) predicted behavioral regulation between prekindergarten and kindergarten. Results indicated that children from…

  19. Implementation of Labour Market Regulating Factors for Entrepreneurship Development in Latvia

    OpenAIRE

    Ieva Brence

    2010-01-01

    Research hypothesis - changes in the set of labour market regulating factors would promote entrepreneurship development in Latvia, however entrepreneurs are not always ready to apply such changes. The first part of the doctoral thesis is theoretical. Analysis of conceptual fundamentals on labour market flexibility and labour market regulation factors and their influence on entrepreneurship development is included, by providing more detailed analysis of minimum wage, part-time employment, a...

  20. FOXO3a-dependent regulation of Puma in response to cytokine/growth factor withdrawal

    OpenAIRE

    You, Han; Pellegrini, Marc; Tsuchihara, Katsuya; Yamamoto, Kazuo; Hacker, Georg; Erlacher, Miriam; Villunger, Andreas; Mak, Tak W.

    2006-01-01

    Puma is an essential mediator of p53-dependent and -independent apoptosis in vivo. In response to genotoxic stress, Puma is induced in a p53-dependent manner. However, the transcription factor driving Puma up-regulation in response to p53-independent apoptotic stimuli has yet to be identified. Here, we show that FOXO3a up-regulates Puma expression in response to cytokine or growth factor deprivation. Importantly, dysregulated Akt signaling in lymphoid cells attenuated Puma induction upon cyto...

  1. Effects of Hepatocyte Nuclear Factor-4α on the Regulation of the Hepatic Acute Phase Response

    OpenAIRE

    Wang, Zhongyan; Burke, Peter A.

    2007-01-01

    Following injury, a large number of hepatic acute phase genes are rapidly modulated at the transcriptional level to restore metabolic homeostasis an limit tissue damage. Hepatocyte nuclear factor 4α (HNF-4α) is a liver-enriched transcription factor that controls embryonic liver development and regulates tissue specific gene expression in adult liver cells. Many genes encoding acute phase proteins contain HNF-4α binding sites in their promoter regions and are transcriptionally regulated by HNF...

  2. MHCI Requires MEF2 Transcription Factors to Negatively Regulate Synapse Density during Development and in Disease

    OpenAIRE

    Elmer, Bradford M.; Estes, Myka L.; Barrow, Stephanie L.; McAllister, A. Kimberley

    2013-01-01

    Major histocompatibility complex class I (MHCI) molecules negatively regulate cortical connections and are implicated in neurodevelopmental disorders, including autism spectrum disorders and schizophrenia. However, the mechanisms that mediate these effects are unknown. Here, we report a novel MHCI signaling pathway that requires the myocyte enhancer factor 2 (MEF2) transcription factors. In young rat cortical neurons, MHCI regulates MEF2 in an activity-dependent manner and requires calcineuri...

  3. Studies of the C/EBP family of transcription factors : cloning, regulation, and expression

    OpenAIRE

    Antonson, Per

    1996-01-01

    The CCAAT/Enhancer Binding Protein (C/EBP) family belongs to the basic leucine zipperclass of transcription factors with a total of 6 members having been identified in this familyso far. This gene family has been mainly implicated in regulation of cell specific geneexpression and differentiation.In order to identify factors important for the regulation of the mouse C/EBPa gene thepromoter region was characterised using nuclear extracts prepared from liver. Several siteswithin the promoter whi...

  4. Human factors regulation in response to advanced reactor design trends

    International Nuclear Information System (INIS)

    This paper presents the direction being taken in the Canadian regulatory program to guide the incorporation of human factors principles, knowledge, information, and methods in activities such as those that address the design and implementation of the advanced control room (ACR) in nuclear power plants. Within the current activity in the international nuclear industry aimed at the development of ACR concepts, the steps that are being taken to develop design review guidelines for ACRs, such as the work sponsored by the U.S. Nuclear Regulatory Commission are filling an identified important need. The salient feature of most ACR projects is the increased use of digital technology for the analysis, synthesis, management, and display of information. The greatly increased functionality of the devices that can be introduced during such projects allows changes to be made at the design and implementation stages that are not necessarily based on prior function allocation or task analyses

  5. OK-432 reduces mortality and bacterial translocation in irradiated and granulocyte-colony stimulating factor (G-CSF)-treated mice

    Energy Technology Data Exchange (ETDEWEB)

    Nose, Masako; Uzawa, Akiko; Ogyu, Toshiaki [National Inst. of Radiological Sciences, Chiba (Japan); Suzuki, Gen

    2001-06-01

    Acute radiation induces bacterial translocation from the gut, followed by systemic infection and sepsis. In order to reduce the mortality after acute whole body irradiation, it is essential to control bacterial translocation. In this study, we established a bacterial translocation assay as a sensitive method to detect minor mucosal injury by radiation. By utilizing this assay, we evaluated the adverse effects, if any, of hematopoietic reagents on the mucosal integrity in the respiratory and gastro-intestinal tracts. Bacterial translocation to the liver and spleen occurred after whole-body irradiation if the dose exceeded 6 Gy. The administration of G-CSF unexpectedly increased the bacterial translocation in 8 Gy-irradiated mice. The pharmaceutical preparation of low-virulent Streptococcus pyogenes, OK-432, significantly reduced the endotoxin levels in peripheral blood without any reduction of bacterial translocation. A combined treatment with G-CSF and OK-432 decreased bacterial translocation and prevented death. This result indicates that the early administration of G-CSF has an adverse effect on bacterial translocation, and that a combined treatment of G-CSF and OK-432 attenuates the adverse effect of G-CSF and improves the survival rate after acute irradiation. (author)

  6. OK-432 reduces mortality and bacterial translocation in irradiated and granulocyte-colony stimulating factor (G-CSF)-treated mice

    International Nuclear Information System (INIS)

    Acute radiation induces bacterial translocation from the gut, followed by systemic infection and sepsis. In order to reduce the mortality after acute whole body irradiation, it is essential to control bacterial translocation. In this study, we established a bacterial translocation assay as a sensitive method to detect minor mucosal injury by radiation. By utilizing this assay, we evaluated the adverse effects, if any, of hematopoietic reagents on the mucosal integrity in the respiratory and gastro-intestinal tracts. Bacterial translocation to the liver and spleen occurred after whole-body irradiation if the dose exceeded 6 Gy. The administration of G-CSF unexpectedly increased the bacterial translocation in 8 Gy-irradiated mice. The pharmaceutical preparation of low-virulent Streptococcus pyogenes, OK-432, significantly reduced the endotoxin levels in peripheral blood without any reduction of bacterial translocation. A combined treatment with G-CSF and OK-432 decreased bacterial translocation and prevented death. This result indicates that the early administration of G-CSF has an adverse effect on bacterial translocation, and that a combined treatment of G-CSF and OK-432 attenuates the adverse effect of G-CSF and improves the survival rate after acute irradiation. (author)

  7. Alternative Splicing Regulation During C. elegans Development: Splicing Factors as Regulated Targets

    OpenAIRE

    Sergio Barberan-Soler; Zahler, Alan M.

    2008-01-01

    Alternative splicing generates protein diversity and allows for post-transcriptional gene regulation. Estimates suggest that 10% of the genes in Caenorhabditis elegans undergo alternative splicing. We constructed a splicing-sensitive microarray to detect alternative splicing for 352 cassette exons and tested for changes in alternative splicing of these genes during development. We found that the microarray data predicted that 62/352 (approximately 18%) of the alternative splicing events studi...

  8. Cinnamide Derivatives of d-Mannose as Inhibitors of the Bacterial Virulence Factor LecB from Pseudomonas aeruginosa.

    Science.gov (United States)

    Sommer, Roman; Hauck, Dirk; Varrot, Annabelle; Wagner, Stefanie; Audfray, Aymeric; Prestel, Andreas; Möller, Heiko M; Imberty, Anne; Titz, Alexander

    2015-12-01

    Pseudomonas aeruginosa is an opportunistic Gram-negative pathogen with high antibiotic resistance. Its lectin LecB was identified as a virulence factor and is relevant in bacterial adhesion and biofilm formation. Inhibition of LecB with carbohydrate-based ligands results in a decrease in toxicity and biofilm formation. We recently discovered two classes of potent drug-like glycomimetic inhibitors, that is, sulfonamides and cinnamides of d-mannose. Here, we describe the chemical synthesis and biochemical evaluation of more than 20 derivatives with increased potency compared to the unsubstituted cinnamide. The structure-activity relationship (SAR) obtained and the extended biophysical characterization allowed the experimental determination of the binding mode of these cinnamides with LecB. The established surface binding mode now allows future rational structure-based drug design. Importantly, all glycomimetics tested showed extended receptor residence times with half-lives in the 5-20 min range, a prerequisite for therapeutic application. Thus, the glycomimetics described here provide an excellent basis for future development of anti-infectives against this multidrug-resistant pathogen. PMID:27308201

  9. The role of host and microbial factors in the pathogenesis of pneumococcal bacteraemia arising from a single bacterial cell bottleneck.

    Directory of Open Access Journals (Sweden)

    Alice Gerlini

    2014-03-01

    Full Text Available The pathogenesis of bacteraemia after challenge with one million pneumococci of three isogenic variants was investigated. Sequential analyses of blood samples indicated that most episodes of bacteraemia were monoclonal events providing compelling evidence for a single bacterial cell bottleneck at the origin of invasive disease. With respect to host determinants, results identified novel properties of splenic macrophages and a role for neutrophils in early clearance of pneumococci. Concerning microbial factors, whole genome sequencing provided genetic evidence for the clonal origin of the bacteraemia and identified SNPs in distinct sub-units of F0/F1 ATPase in the majority of the ex vivo isolates. When compared to parental organisms of the inoculum, ex-vivo pneumococci with mutant alleles of the F0/F1 ATPase had acquired the capacity to grow at low pH at the cost of the capacity to grow at high pH. Although founded by a single cell, the genotypes of pneumococci in septicaemic mice indicate strong selective pressure for fitness, emphasising the within-host complexity of the pathogenesis of invasive disease.

  10. Bacterial antigen induced release of soluble vascular endothelial growth factor (VEGF) and VEGFR1 before and after surgery

    DEFF Research Database (Denmark)

    Svendsen, Mads N; Lykke, J; Werther, Kim;

    2005-01-01

    -induced release of sVEGF and sVEGFR1 from whole blood in vitro. MATERIAL AND METHODS: Sixty-one patients with abdominal diseases undergoing five different surgical procedures were included in the study. Blood samples were drawn from patients before and after the operation. White blood cells and platelets were......OBJECTIVE: The influence of surgery on release of soluble vascular endothelial growth factor (sVEGF) and the soluble inhibitory receptor (sVEGFR1) is unknown. The effect of major and minor surgery on variations in sVEGF and sVEGFR1 concentrations in vivo was studied, and on bacterial antigen...... counted, and plasma sVEGF and sVEGFR1 were determined. Whole blood from each blood sample was stimulated in vitro with bacteria-derived antigens (lipopolysaccharides or protein A) and sVEGF and sVEGFR1 levels were subsequently determined in the supernatants. RESULTS: Neither sVEGF nor sVEGFR1...

  11. Regulation of voltage-gated sodium channel expression in cancer: hormones, growth factors and auto-regulation.

    Science.gov (United States)

    Fraser, Scott P; Ozerlat-Gunduz, Iley; Brackenbury, William J; Fitzgerald, Elizabeth M; Campbell, Thomas M; Coombes, R Charles; Djamgoz, Mustafa B A

    2014-03-19

    Although ion channels are increasingly being discovered in cancer cells in vitro and in vivo, and shown to contribute to different aspects and stages of the cancer process, much less is known about the mechanisms controlling their expression. Here, we focus on voltage-gated Na(+) channels (VGSCs) which are upregulated in many types of carcinomas where their activity potentiates cell behaviours integral to the metastatic cascade. Regulation of VGSCs occurs at a hierarchy of levels from transcription to post-translation. Importantly, mainstream cancer mechanisms, especially hormones and growth factors, play a significant role in the regulation. On the whole, in major hormone-sensitive cancers, such as breast and prostate cancer, there is a negative association between genomic steroid hormone sensitivity and functional VGSC expression. Activity-dependent regulation by positive feedback has been demonstrated in strongly metastatic cells whereby the VGSC is self-sustaining, with its activity promoting further functional channel expression. Such auto-regulation is unlike normal cells in which activity-dependent regulation occurs mostly via negative feedback. Throughout, we highlight the possible clinical implications of functional VGSC expression and regulation in cancer. PMID:24493753

  12. Role of environmental factors for the vertical distribution (0–1000 m of marine bacterial communities in the NW Mediterranean Sea

    Directory of Open Access Journals (Sweden)

    J. F. Ghiglione

    2008-12-01

    Full Text Available Bacterioplankton plays a central role in energy and matter fluxes in the sea, yet the factors that constrain its variation in marine systems are still poorly understood. Here we use the explanatory power of direct multivariate gradient analysis to evaluate the driving forces exerted by environmental parameters on bacterial community distribution in the water column. We gathered and analysed data from a one month sampling period from the surface to 1000 m depth at the JGOFS-DYFAMED station (NW Mediterranean Sea. This station is characterized by very poor horizontal advection currents which makes it an ideal model to test hypotheses on the causes of vertical stratification of bacterial communities. Capillary electrophoresis single strand conformation polymorphism (CE-SSCP fingerprinting profiles analyzed using multivariate statistical methods demonstrated a vertical zonation of bacterial assemblages in three layers, above, in or just below the chlorophyll maximum and deeper, that remained stable during the entire sampling period. Through the use of direct gradient multivariate ordination analyses we demonstrate that a complex array of biogeochemical parameters is the driving force behind bacterial community structure shifts in the water column. Physico-chemical parameters such as phosphate, nitrate, salinity and to a lesser extent temperature, oxygen, dissolved organic carbon and photosynthetically active radiation acted in synergy to explain bacterial assemblages changes with depth. Analysis of lipid biomarkers of organic matter sources and fates suggested that bacterial community structure in the surface layers was in part explained by lipids of chloroplast origin. Further detailed analysis of pigment-based phytoplankton diversity gave evidence of a compartmentalized influence of several phytoplankton groups on bacterial community structure in the first 150 m depth.

  13. Factors regulating interaction between trophoblast and human endometrium.

    Science.gov (United States)

    Flamigni, C; Bulletti, C; Polli, V; Ciotti, P M; Prefetto, R A; Galassi, A; Di Cosmo, E

    1991-01-01

    Implantation is a crucial step in human reproduction. Disturbances of this process are responsible for pregnancy failure after both in vivo and in vitro fertilization. The endometrium provides the implanting embryo with a unique substratum where the embryo communicates with biochemical signals, attaches itself, penetrates and grows without blood circulation. The highly proliferative phase of the cytotrophoblast, during early human embryogenesis, may be due to endogenous production of growth factors that may establish autocrine/short range paracrine stimulator loops which explain the tumor-like properties of these tissues. Endometrial BM penetration and stroma invasion may be due to the proteolytic capability of the human embryo. It is suggested that collagenase and the urokinase-like plasminogen activator are responsible for this activity. To clarify the molecular mechanisms involved in human embryo implantation several models are suggested: culture of blastocysts, culture of endometrial cells, and endometrial explant co-culture. Human blastocysts cultured with whole perfused human uteri make it possible to recognize some aspects of the entire implantation process and give us the possibility of improving the benefits provided by new technologies in reproductive medicine and reducing embryonic loss at an early stage. PMID:2064179

  14. Blue-light-regulated transcription factor, Aureochrome, in photosynthetic stramenopiles.

    Science.gov (United States)

    Takahashi, Fumio

    2016-03-01

    During the course of evolution through various endosymbiotic processes, diverse photosynthetic eukaryotes acquired blue light (BL) responses that do not use photosynthetic pathways. Photosynthetic stramenopiles, which have red algae-derived chloroplasts through secondary symbiosis, are principal primary producers in aquatic environments, and play important roles in ecosystems and aquaculture. Through secondary symbiosis, these taxa acquired BL responses, such as phototropism, chloroplast photo-relocation movement, and photomorphogenesis similar to those which green plants acquired through primary symbiosis. Photosynthetic stramenopile BL receptors were undefined until the discovery in 2007, of a new type of BL receptor, the aureochrome (AUREO), from the photosynthetic stramenopile alga, Vaucheria. AUREO has a bZIP domain and a LOV domain, and thus BL-responsive transcription factor. AUREO orthologs are only conserved in photosynthetic stramenopiles, such as brown algae, diatoms, and red tide algae. Here, a brief review is presented of the role of AUREOs as photoreceptors for these diverse BL responses and their biochemical properties in photosynthetic stramenopiles. PMID:26781435

  15. Growth factor regulation of sugar uptake in cultured cells

    International Nuclear Information System (INIS)

    Mouse EGF stimulates the uptake of 2-deoxygluclose (dGIc), a non-metabolized glucose analogue, into cultured mouse 3T3 fibroblasts (Clone 1) 2 to 4 fold, and EGF dependent Balb/MK-1 epidermal kerotinocytes, 5 to 8 fold. Initial stimulation is detected at 15 minutes. Maximal effects are seen at 2 hours with 10 ng/ml EGF. Binding of 125I-labeled EGF to cells is rapid and complete by 2 hours at 370C. Antibodies which specifically inhibit 125I-labeled EGF binding to cells inhibit EGF stimulation as much as 85%. Human platelet derived TGF-β stimulates dGlc uptake up to 5 fold. Maximum effects are seen with 1 ng/ml TGF-β within 2 hours and stimulation is detected 30 minutes after exposure to 0.1 ng/ml, the minimum effective concentration. TGF-β, like EGF, stimulates sugar transport into Balb/MK-1 cells without additional factors. However, neither stimulates uptake in a 3T3 variant, NR-6, which is EGF-receptor negative. The co-addition of EGF and/or PDGF enhances TGF-β stimulation. Binding of 125I-labeled TGF-β is nearly complete by 1 hour at 370C, but continues to increase for as long as 4 hours after addition. Antibodies which inhibit EGF binding have no effect on TGF-β binding, but they block TGF-β stimulation of hexose uptake. It is concluded from these results that the TGF-β receptor is distinct from the EGF receptor, and that although TGF-β stimulation of dGLc uptake does not require exogenously added EGF, it does require an active or available EGF receptor kinase system

  16. Etiology and Risk Factors of Acute Gastroenteritis in a Taipei Emergency Department: Clinical Features for Bacterial Gastroenteritis

    Directory of Open Access Journals (Sweden)

    Chao-Chih Lai

    2016-04-01

    Full Text Available Background: The causative pathogen is rarely identified in the emergency department (ED, since the results of cultures are usually unavailable. As a result, antimicrobial treatment may be overused. The aim of our study was to investigate the pathogens, risk factors of acute gastroenteritis, and predictors of acute bacterial gastroenteritis in the ED. Methods: We conducted a matched case-control study of 627 stool samples and 612 matched pairs. Results: Viruses (41.3% were the leading cause of gastroenteritis, with noroviruses (32.2% being the most prevalent, followed by bacteria (26.8% and Giardia lamblia (12.4%. Taking antacids (adjusted odds ratio [aOR] 4.10; 95% confidence interval [CI], 2.57–6.53, household members/classmates with gastroenteritis (aOR 4.69; 95% CI, 2.76–7.96, attending a banquet (aOR 2.29; 95% CI, 1.64–3.20, dining out (aOR 1.70; 95% CI, 1.13–2.54, and eating raw oysters (aOR 3.10; 95% CI, 1.61–5.94 were highly associated with gastroenteritis. Elders (aOR 1.04; 05% CI, 1.02–1.05, those with CRP >10 mg/L (aOR 2.04; 95% CI, 1.15–3.62, or those who were positive for fecal leukocytes (aOR 2.04; 95% CI, 1.15–3.62 or fecal occult blood (aOR 1.97; 95% CI, 1.03–3.77 were more likely to be hospitalized in ED. In addition, presence of fecal leukocytes (time ratio [TR] 1.22; 95% CI, 1.06–1.41, abdominal pain (TR 1.20; 95% CI, 1.07–1.41, and frequency of vomiting (TR 0.79; 95% CI, 0.64–0.98 were significantly associated with the duration of acute gastroenteritis. Presence of fecal leukocytes (aOR 2.08; 95% CI, 1.42–3.05, winter season (aOR 0.45; 95% CI, 0.28–0.74, frequency of diarrhea (aOR 1.69; 95% CI, 1.01–2.83, and eating shrimp or crab (aOR 1.53; 95% CI, 1.05–2.23 were highly associated with bacterial gastroenteritis. The area under the receiver operating characteristic curve of the final model was 0.68 (95% CI, 0.55–0.63. Conclusions: Acute bacterial gastroenteritis was highly associated with

  17. In Silico Identification of Co-transcribed Core Cell Cycle Regulators and Transcription Factors in Arabidopsis

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Regulatory networks involving transcription factors and core cell cycle regulators are expected to play crucial roles in plant growth and development. In this report, we describe the identification of two groups of co-transcribed core cell cycle regulators and transcription factors via a two-step in silico screening. The core cell cycle regulators include TARDY ASYNCHRONOUS MEIOSIS (CYCA1;2), CYCB1;1, CYCB2;1, CDKB1;2, and CDKB2;2 while the transcription factors include CURLY LEAF, AINTEGUMENTA, a MYB protein, two Forkhead-associated domain proteins, and a SCARECROW family protein. Promoter analysis revealed a potential web of cross- and self-regulations among the identified proteins. Because one criterion for screening for these genes is that they are predominantly transcribed in young organs but not in mature organs, these genes are likely to be particularly involved in Arabidopsis organ growth.

  18. Effects of Interactions of Auxin-Producing Bacteria and Bacterial-Feeding Nematodes on Regulation of Peanut Growths

    OpenAIRE

    Li Xu; Wensi Xu; Ying Jiang; Feng Hu; Huixin Li

    2015-01-01

    The influences of an IAA (indole-3-acetic acid)-producing bacterium (Bacillus megaterium) and two bacterial-feeding nematodes (Cephalobus sp. or Mesorhabditis sp.) on the growth of peanut (Arachis hypogaea L. cv. Haihua 1) after various durations of time were investigated in natural soils. The addition of bacteria and nematodes and incubation time all significantly affected plant growth, plant root growth, plant nutrient concentrations, soil nutrient concentrations, soil microorganisms and so...

  19. Polysaccharide Capsule and Sialic Acid-Mediated Regulation Promote Biofilm-Like Intracellular Bacterial Communities during Cystitis ▿

    OpenAIRE

    Anderson, Gregory G.; Goller, Carlos C.; Justice, Sheryl; Hultgren, Scott J.; Seed, Patrick C.

    2010-01-01

    Uropathogenic Escherichia coli (UPEC) is the leading cause of urinary tract infections (UTIs). A murine UTI model has revealed an infection cascade whereby UPEC undergoes cycles of invasion of the bladder epithelium, intracellular proliferation in polysaccharide-containing biofilm-like masses called intracellular bacterial communities (IBC), and then dispersal into the bladder lumen to initiate further rounds of epithelial colonization and invasion. We predicted that the UPEC K1 polysaccharid...

  20. Inferring yeast cell cycle regulators and interactions using transcription factor activities

    Directory of Open Access Journals (Sweden)

    Galbraith Simon J

    2005-06-01

    Full Text Available Abstract Background Since transcription factors are often regulated at the post-transcriptional level, their activities, rather than expression levels may provide valuable information for investigating functions and their interactions. The recently developed Network Component Analysis (NCA and its generalized form (gNCA provide a robust framework for deducing the transcription factor activities (TFAs from various types of DNA microarray data and transcription factor-gene connectivity. The goal of this work is to demonstrate the utility of TFAs in inferring transcription factor functions and interactions in Saccharomyces cerevisiae cell cycle regulation. Results Using gNCA, we determined 74 TFAs from both wild type and fkh1 fkh2 deletion mutant microarray data encompassing 1529 ORFs. We hypothesized that transcription factors participating in the cell cycle regulation exhibit cyclic activity profiles. This hypothesis was supported by the TFA profiles of known cell cycle factors and was used as a basis to uncover other potential cell cycle factors. By combining the results from both cluster analysis and periodicity analysis, we recovered nearly 90% of the known cell cycle regulators, and identified 5 putative cell cycle-related transcription factors (Dal81, Hap2, Hir2, Mss11, and Rlm1. In addition, by analyzing expression data from transcription factor knockout strains, we determined 3 verified (Ace2, Ndd1, and Swi5 and 4 putative interaction partners (Cha4, Hap2, Fhl1, and Rts2 of the forkhead transcription factors. Sensitivity of TFAs to connectivity errors was determined to provide confidence level of these predictions. Conclusion By subjecting TFA profiles to analyses based upon physiological signatures we were able to identify cell cycle related transcription factors consistent with current literature, transcription factors with potential cell cycle dependent roles, and interactions between transcription factors.

  1. RpoN Regulates Virulence Factors of Pseudomonas aeruginosa via Modulating the PqsR Quorum Sensing Regulator

    Directory of Open Access Journals (Sweden)

    Zhao Cai

    2015-11-01

    Full Text Available The alternative sigma factor RpoN regulates many cell functions, such as motility, quorum sensing, and virulence in the opportunistic pathogen Pseudomonas aeruginosa (P. aeruginosa. P. aeruginosa often evolves rpoN-negative variants during the chronic infection in cystic fibrosis patients. It is unclear how RpoN interacts with other regulatory mechanisms to control virulence of P. aeruginosa. In this study, we show that RpoN modulates the function of PqsR, a quorum sensing receptor regulating production of virulence factors including the phenazine pyocyanin. The ∆rpoN mutant is able to synthesize 4-quinolone signal molecule HHQ but unable to activate PqsR and Pseudomonas quinolone signal (pqs quorum sensing. The ∆rpoN mutant produces minimal level of pyocyanin and is unable to produce the anti-staphylococcal agents. Providing pqsR in trans in the ∆rpoN mutant restores its pqs quorum sensing and virulence factor production to the wild-type level. Our study provides evidence that RpoN has a regulatory effect on P. aeruginosa virulence through modulating the function of the PqsR quorum sensing regulator.

  2. Factors affecting self-regulated learning in medical students: a qualitative study

    Science.gov (United States)

    Jouhari, Zahra; Haghani, Fariba; Changiz, Tahereh

    2015-01-01

    Introduction Clinical courses are required of all medical students and means that they must develop the key skill of self-regulation during learning. The ability to self-regulate learning strategies is affected by different factors. This study determined the views of medical students on the factors affecting self-regulated learning (SRL). Method This study uses a qualitative approach and the content analysis method. Nineteen medical students in their fourth, fifth, and sixth years of study at Isfahan University of Medical Science participated in semi-structured, in-depth interviews. The students were selected using purposive sampling based on their overall grade point average (GPA). Results Five main themes were found to affect SRL. These themes included family with the two subthemes of family supervisory and supportive roles; peers with the two subthemes of facilitating and inhibiting roles; instructors with the two subthemes of personal and educational instructor's characteristics; educational environment with the two subthemes of facilitator and inhibitor roles; and student with the two subthemes of facilitating and inhibiting personal factors. Conclusion The outcomes of student understanding of the factors affecting self-regulation indicate that facilitating factors should be used on an individual basis to reduce the effect of inhibiting factors to improve self-regulation in students. PMID:26549046

  3. Factors affecting self-regulated learning in medical students: a qualitative study

    Directory of Open Access Journals (Sweden)

    Zahra Jouhari

    2015-11-01

    Full Text Available Introduction: Clinical courses are required of all medical students and means that they must develop the key skill of self-regulation during learning. The ability to self-regulate learning strategies is affected by different factors. This study determined the views of medical students on the factors affecting self-regulated learning (SRL. Method: This study uses a qualitative approach and the content analysis method. Nineteen medical students in their fourth, fifth, and sixth years of study at Isfahan University of Medical Science participated in semi-structured, in-depth interviews. The students were selected using purposive sampling based on their overall grade point average (GPA. Results: Five main themes were found to affect SRL. These themes included family with the two subthemes of family supervisory and supportive roles; peers with the two subthemes of facilitating and inhibiting roles; instructors with the two subthemes of personal and educational instructor's characteristics; educational environment with the two subthemes of facilitator and inhibitor roles; and student with the two subthemes of facilitating and inhibiting personal factors. Conclusion: The outcomes of student understanding of the factors affecting self-regulation indicate that facilitating factors should be used on an individual basis to reduce the effect of inhibiting factors to improve self-regulation in students.

  4. Sox10 regulates ciliary neurotrophic factor gene expression in Schwann cells

    OpenAIRE

    Ito, Yasuhiro; Wiese, Stefan; Funk, Natalja; Chittka, Alexandra; Rossoll, Wilfried; Bömmel, Heike; Watabe, Kazuhiko; Wegner, Michael; Sendtner, Michael

    2006-01-01

    Ciliary neurotrophic factor (Cntf) plays an essential role in postnatal maintenance of spinal motoneurons. Whereas the expression of this neurotrophic factor is low during embryonic development, it is highly up-regulated after birth in myelinating Schwann cells of rodents. To characterize the underlying transcriptional mechanisms, we have analyzed and compared the effects of various glial transcription factors. In contrast to Pit-1, Oct-1, Unc-86 homology region (POU) domain class 3, transcri...

  5. Activity Of Bacterial Proteolytic Enzymes on Antinutritional Factors in Soybeans and the Effect on Growth and Organ Weights of Piglets

    Institute of Scientific and Technical Information of China (English)

    HuoGui-cheng; YangLi-jie; 等

    1999-01-01

    A significant reduction of trypsin inhibitory activity by selected bacterial proteolytic enzymes was demonstrated in vitro.Two trials were conducted to examine the capacity of the tested enzymes to inactivate soybean ANFs in vivo.In trial I,twenty-four piglets weaned at four weeks of age were assigned in replicate groups of 4 piglets per pen to one of three dietary treatments:(1)control;(2)Enzyme 1-supplemented(E1);(3)Enzyme 2-supplemented (E2).In trial II,twenty piglets weaned at five weeks of age were alloted to five treatment diets:(1)contro,1:(2) 0.1% P4-supplemented;(3)0.5% P4-supplemented;(4)0.1% P7-supplemented;(5)0.5% P7-supplemented.The optimum pH for hydrolysis was 8 for E.9-11 for E2,8.5 for P4 and nuctral for P7.After 17 days of the trial,daily gain of piglets on enzymes E1 and E2 was 36% and 18% more than that in the control group,although the difference was not significant.the animals on the treated groups had a tendency to have lighter heart(7.8 and 5.9%),spleen(11.1 and 7.4%) and pancreas(16.7 and 12.5% for E1 and E2 respectively)in relation to empty body weight than those in the control.the small intestine of pigs on the treated groups was significantly lighter(18.9 for E1 and 7.7% for E2) than that in the control(P<0.05).The stomach(26.4 and 24%,p=0.198) and cecum (21.9 and 9.4%,p=0.114) also showed the same pattern.The growth depression was attributed to reduced feed intake caused by antinutritional factors in soybeans.It is concluded that supplements of proteolytic enzymes E1 or E2 had a positive effect on growth and efficiency and caused much less reaction in the gut as manifested by the weight of the tract and of its accessory organs.Dietary saupplements of P4 or P7 had no significant effect on growth,but reduced reaction of soybean antinutritional factors in the gut,especialy P4 in dose of 0.5%.The growth depression was attributed to low feed intake caused by antinutritional factors in soybeans.

  6. Activity Of Bacterial Proteolytic Enzymes on Antinutritional Factors in Soybeans and the Effect on Growth and Organ Weights of Piglets

    Institute of Scientific and Technical Information of China (English)

    1999-01-01

    A significant reduction of trypsin inhibitory activity by selected bacterial proteolytic enzymes was demon- strated in vitro. Two trials were conducted to examine the capacity of the tested enzymes to inactivate soybean ANFs in vivo. In trial I,twenty-four piglets weaned at four weeks of age were assigned in replicate groups of 4 piglets per pen to one of three dietary treatments: (1)control; (2)Enzyme 1-supplemented(E1); (3)Enzyme 2-supplemented (E2). In trial II,twenty piglets weaned at five weeks of age were alloted to five treatment di- ets:(1)contro,l: (2)0. 1% P4-supplemented; (3)0. 5% P4-supplemented; (4)0. 1% P7-supplemented; (5)0. 5% P7-supplemented. The optimum pH for hydrolysis was 8 for E,9-11 for E2,8.5 for P4 and nuctral for P7. After 17 days of the trial,daily gain of piglets on enzymes E1 and E2 was 36% and 18% more than that in the control group,although the difference was not significant. The animals on the treated groups had a tendency to have lighter heart(7.8 and 5.9%),spleen(11. 1 and 7.4%) and pancreas(16.7 and 12.5% for E1 and E2 respectively)in relation to empty body weight than those in the control. The small intestine of pigs on the treated groups was significantly lighter(18.9 for E1 and 7.7% for E2) than that in the control( P < 0.05 ). The stomach (26.4 and 24%,p=0. 198) and cecum(21.9and 9.4%,p=0. 114) also showed the same pat- tern. The growth depression was attributed to reduced feed intake caused by antinutritional factors in soy beans. It is concluded that supplements of proteolytic enzymes E1 or E2 had a positive effect on growth and ef- ficiency and caused much less reaction in the gut as manifested by the weight of the tract and of its accessory organs. Dietary saupplements of P4 or P7 had no significant effect on growth,but reduced reaction of soybean antinutritional factors in the gut,especialy P4 in dose of 0.5%. The growth depression was attributed to low feed intake caused by antinutritional

  7. Splicing factor SR34b mutation reduces cadmium tolerance in Arabidopsis by regulating iron-regulated transporter 1 gene

    International Nuclear Information System (INIS)

    Highlights: • Arabidopsis splicing factor SR34b gene is cadmium-inducible. • SR34b T-DNA insertion mutant is sensitive to cadmium due to high cadmium uptake. • SR34b is a regulator of cadmium transporter IRT1 at the posttranscription level. • These results highlight the roles of splicing factors in cadmium tolerance of plant. - Abstract: Serine/arginine-rich (SR) proteins are important splicing factors. However, the biological functions of plant SR proteins remain unclear especially in abiotic stresses. Cadmium (Cd) is a non-essential element that negatively affects plant growth and development. In this study, we provided clear evidence for SR gene involved in Cd tolerance in planta. Systemic expression analysis of 17 Arabidopsis SR genes revealed that SR34b is the only SR gene upregulated by Cd, suggesting its potential roles in Arabidopsis Cd tolerance. Consistent with this, a SR34b T-DNA insertion mutant (sr34b) was moderately sensitive to Cd, which had higher Cd2+ uptake rate and accumulated Cd in greater amounts than wild-type. This was due to the altered expression of iron-regulated transporter 1 (IRT1) gene in sr34b mutant. Under normal growth conditions, IRT1 mRNAs highly accumulated in sr34b mutant, which was a result of increased stability of IRT1 mRNA. Under Cd stress, however, sr34b mutant plants had a splicing defect in IRT1 gene, thus reducing the IRT1 mRNA accumulation. Despite of this, sr34b mutant plants still constitutively expressed IRT1 proteins under Cd stress, thereby resulting in Cd stress-sensitive phenotype. We therefore propose the essential roles of SR34b in posttranscriptional regulation of IRT1 expression and identify it as a regulator of Arabidopsis Cd tolerance

  8. Splicing factor SR34b mutation reduces cadmium tolerance in Arabidopsis by regulating iron-regulated transporter 1 gene

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Wentao; Du, Bojing; Liu, Di; Qi, Xiaoting, E-mail: qixiaoting@cnu.edu.cn

    2014-12-12

    Highlights: • Arabidopsis splicing factor SR34b gene is cadmium-inducible. • SR34b T-DNA insertion mutant is sensitive to cadmium due to high cadmium uptake. • SR34b is a regulator of cadmium transporter IRT1 at the posttranscription level. • These results highlight the roles of splicing factors in cadmium tolerance of plant. - Abstract: Serine/arginine-rich (SR) proteins are important splicing factors. However, the biological functions of plant SR proteins remain unclear especially in abiotic stresses. Cadmium (Cd) is a non-essential element that negatively affects plant growth and development. In this study, we provided clear evidence for SR gene involved in Cd tolerance in planta. Systemic expression analysis of 17 Arabidopsis SR genes revealed that SR34b is the only SR gene upregulated by Cd, suggesting its potential roles in Arabidopsis Cd tolerance. Consistent with this, a SR34b T-DNA insertion mutant (sr34b) was moderately sensitive to Cd, which had higher Cd{sup 2+} uptake rate and accumulated Cd in greater amounts than wild-type. This was due to the altered expression of iron-regulated transporter 1 (IRT1) gene in sr34b mutant. Under normal growth conditions, IRT1 mRNAs highly accumulated in sr34b mutant, which was a result of increased stability of IRT1 mRNA. Under Cd stress, however, sr34b mutant plants had a splicing defect in IRT1 gene, thus reducing the IRT1 mRNA accumulation. Despite of this, sr34b mutant plants still constitutively expressed IRT1 proteins under Cd stress, thereby resulting in Cd stress-sensitive phenotype. We therefore propose the essential roles of SR34b in posttranscriptional regulation of IRT1 expression and identify it as a regulator of Arabidopsis Cd tolerance.

  9. Microinjection of Francisella tularensis and Listeria monocytogenes reveals the importance of bacterial and host factors for successful replication.

    Science.gov (United States)

    Meyer, Lena; Bröms, Jeanette E; Liu, Xijia; Rottenberg, Martin E; Sjöstedt, Anders

    2015-08-01

    Certain intracellular bacteria use the host cell cytosol as the replicative niche. Although it has been hypothesized that the successful exploitation of this compartment requires a unique metabolic adaptation, supportive evidence is lacking. For Francisella tularensis, many genes of the Francisella pathogenicity island (FPI) are essential for intracellular growth, and therefore, FPI mutants are useful tools for understanding the prerequisites of intracytosolic replication. We compared the growth of bacteria taken up by phagocytic or nonphagocytic cells with that of bacteria microinjected directly into the host cytosol, using the live vaccine strain (LVS) of F. tularensis; five selected FPI mutants thereof, i.e., ΔiglA, ΔiglÇ ΔiglG, ΔiglI, and ΔpdpE strains; and Listeria monocytogenes. After uptake in bone marrow-derived macrophages (BMDM), ASC(-/-) BMDM, MyD88(-/-) BMDM, J774 cells, or HeLa cells, LVS, ΔpdpE and ΔiglG mutants, and L. monocytogenes replicated efficiently in all five cell types, whereas the ΔiglA and ΔiglC mutants showed no replication. After microinjection, all 7 strains showed effective replication in J774 macrophages, ASC(-/-) BMDM, and HeLa cells. In contrast to the rapid replication in other cell types, L. monocytogenes showed no replication in MyD88(-/-) BMDM and LVS showed no replication in either BMDM or MyD88(-/-) BMDM after microinjection. Our data suggest that the mechanisms of bacterial uptake as well as the permissiveness of the cytosolic compartment per se are important factors for the intracytosolic replication. Notably, none of the investigated FPI proteins was found to be essential for intracytosolic replication after microinjection. PMID:26034213

  10. Prevalence, risk factors, and major bacterial causes of camel mastitis in Borana Zone, Oromia Regional State, Ethiopia.

    Science.gov (United States)

    Regassa, Alemayehu; Golicha, Gelma; Tesfaye, Dawit; Abunna, Fufa; Megersa, Bekele

    2013-10-01

    A cross-sectional study was carried out from November 2010 up to April 2011 to estimate mastitis prevalence and associated risk factors and to assess its bacterial causes in traditionally managed camels in Borana Zone, Southern Ethiopia. Thus, 348 lactating camels were examined clinically, and subclinical cases were checked with California mastitis test (CMT). The overall prevalence of mastitis was 44.8 % (156/348), comprising clinical (19, 5.4 %) and subclinical (137, 39.4 %) cases. The quarter level prevalence of mastitis was 24.0 % (334/1,392). Of the total 1,392 examined teats, 30 were blind, and hence, from the 1,362 non-blind CMT-examined teats, 22.3 % (304/1,362) were CMT positive. Of the 304 CMT-positive samples, 264 were culture positive (197 Gram-positive, 41 Gram-negative, and 26 mixed isolates), and 40 were culture negative. The prevalence of Staphylococcus aureus was found to be the highest at both the animal (12.8 %, 39/304) and quarter level (2.9 %, 39/1,362). Regression analysis revealed higher likelihood of mastitis occurrence among camels from Dharito (OR = 3.4, 95 % confidence interval (CI) = 1.8, 6.4), Gagna (OR = 3.4, 95 % CI = 1.8, 6.5), and Haro Bake (OR = 2.6, 95 % CI = 1.3, 5.1) than camels from Surupha. Likewise, there was higher chance of mastitis occurrence among camels at the early lactation stage (OR = 2.3, 95 % CI = 1.1, 4.6) and camels with udder/teat lesions (OR = 13.7, 95 % CI = 1.7, 109.4) than among camels at late lactation stage and camels with healthy udder/teats, respectively. In conclusion, this study reveals the current status of camel mastitis in Southern Ethiopia. PMID:23563738

  11. Genomes and virulence factors of novel bacterial pathogens causing bleaching disease in the marine red alga Delisea pulchra.

    Directory of Open Access Journals (Sweden)

    Neil Fernandes

    Full Text Available Nautella sp. R11, a member of the marine Roseobacter clade, causes a bleaching disease in the temperate-marine red macroalga, Delisea pulchra. To begin to elucidate the molecular mechanisms underpinning the ability of Nautella sp. R11 to colonize, invade and induce bleaching of D. pulchra, we sequenced and analyzed its genome. The genome encodes several factors such as adhesion mechanisms, systems for the transport of algal metabolites, enzymes that confer resistance to oxidative stress, cytolysins, and global regulatory mechanisms that may allow for the switch of Nautella sp. R11 to a pathogenic lifestyle. Many virulence effectors common in phytopathogenic bacteria are also found in the R11 genome, such as the plant hormone indole acetic acid, cellulose fibrils, succinoglycan and nodulation protein L. Comparative genomics with non-pathogenic Roseobacter strains and a newly identified pathogen, Phaeobacter sp. LSS9, revealed a patchy distribution of putative virulence factors in all genomes, but also led to the identification of a quorum sensing (QS dependent transcriptional regulator that was unique to pathogenic Roseobacter strains. This observation supports the model that a combination of virulence factors and QS-dependent regulatory mechanisms enables indigenous members of the host alga's epiphytic microbial community to switch to a pathogenic lifestyle, especially under environmental conditions when innate host defence mechanisms are compromised.

  12. Quorum-sensing regulation governs bacterial adhesion, biofilm development, and host colonization in Pantoea stewartii subspecies stewartii

    OpenAIRE

    Koutsoudis, Maria D.; Tsaltas, Dimitrios; Minogue, Timothy D.; von Bodman, Susanne B.

    2006-01-01

    The phytopathogenic bacterium Pantoea stewartii subsp. stewartii synthesizes stewartan exo/capsular polysaccharide (EPS) in a cell density-dependent manner governed by the EsaI/EsaR quorum-sensing (QS) system. This study analyzes biofilm development and host colonization of the WT and QS regulatory mutant strains of P. stewartii. First, we show that the cell density-dependent synthesis of stewartan EPS, governed by the EsaI/EsaR QS system, is required for proper bacterial adhesion and develop...

  13. Regulation of Cell Fate Determination by Single-Repeat R3 MYB Transcription Factors in Arabidopsis

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Shucai [Northeast Normal University, Changchun, China; Chen, Jay [ORNL

    2014-01-01

    MYB transcription factors regulate multiple aspects of plant growth and development. Among the large family of MYB transcription factors, single-repeat R3 MYB are characterized by their short sequence (<120 amino acids) consisting largely of the single MYB DNA-binding repeat. In the model plant Arabidopsis, R3 MYBs mediate lateral inhibition during epidermal patterning and are best characterized for their regulatory roles in trichome and root hair development. R3 MYBs act as negative regulators for trichome formation but as positive regulators for root hair development. In this article, we provide a comprehensive review on the role of R3 MYBs in the regulation of cell type specification in the model plant Arabidopsis.

  14. Regulation of endothelial metabolism by laminar shear stress and flow-induced transcription factor KLF2

    OpenAIRE

    Doddaballapur, Anuradha

    2016-01-01

    Flow hemodynamics regulates endothelial cell (EC) responses and laminar shear stress induces an atheroprotective and quiescent phenotype. The flow-responsive transcription factor KLF2 is a pivotal mediator of endothelial quiescence, but the precise mechanism is unclear. In this doctoral study, we assessed the hypothesis that laminar shear stress and KLF2 regulate endothelial quiescence by controlling endothelial metabolism. Laminar flow exposure and KLF2 over expression in HUVECs reduced g...

  15. Witnessing Partner Violence in Childhood: Factors Influencing Emotion Regulation Difficulties in College Students

    OpenAIRE

    Amatya, Kaushalendra

    2014-01-01

    Witnessing partner violence (WPV) in childhood and adolescence can have significant impact on psychological functioning throughout development. Studies have shown that parenting factors, perceived social support, coping strategies, age at exposure, and gender can influence the relationship between WPV and outcomes. Although WPV can have serious implications towards emotion regulation abilities, empirical research on the link between WPV and emotion regulation is inadequate. The current stu...

  16. Collagen phagocytosis is regulated by the guanine nucleotide exchange factor Vav2

    OpenAIRE

    Arora, P. D.; Marignani, P A; McCulloch, C. A.

    2008-01-01

    Collagen phagocytosis is a crucial α2β1-integrin-dependent process that mediates extracellular matrix remodeling by fibroblasts. We showed previously that after initial contact with collagen, activated Rac1 accelerates collagen phagocytosis but the Rac guanine nucleotide exchange factors (GEFs) that regulate Rac are not defined. We examined here the GEFs that regulate collagen phagocytosis in mouse fibroblasts. Collagen binding enhanced Rac1 activity (5–20 min) but not Cdc42 or RhoA activity....

  17. Transcription factors and cognate signalling cascades in the regulation of autophagy.

    Science.gov (United States)

    Chandra, Vemika; Bhagyaraj, Ella; Parkesh, Raman; Gupta, Pawan

    2016-05-01

    Autophagy is a process that maintains the equilibrium between biosynthesis and the recycling of cellular constituents; it is critical for avoiding the pathophysiology that results from imbalance in cellular homeostasis. Recent reports indicate the need for the design of high-throughput screening assays to identify targets and small molecules for autophagy modulation. For such screening, however, a better understanding of the regulation of autophagy is essential. In addition to regulation by various signalling cascades, regulation of gene expression by transcription factors is also critical. This review focuses on the various transcription factors as well as the corresponding signalling molecules that act together to translate the stimuli to effector molecules that up- or downregulate autophagy. This review rationalizes the importance of these transcription factors functioning in tandem with cognate signalling molecules and their interfaces as possible therapeutic targets for more specific pharmacological interventions. PMID:25651938

  18. Cooperative Regulation of the Activity of Factor Xa within Prothrombinase by Discrete Amino Acid Regions from Factor Va Heavy Chain†

    OpenAIRE

    Barhoover, Melissa A.; Orban, Tivadar; Bukys, Michael A.; Kalafatis, Michael

    2008-01-01

    The prothrombinase complex catalyzes the activation of prothrombin to α-thrombin. We have repetitively shown that amino acid region 695DYDY698 from the COOH terminus of the heavy chain of factor Va regulates the rate of cleavage of prothrombin at Arg271 by prothrombinase. We have also recently demonstrated that amino acid region 334DY335 is required for the optimal activity of prothrombinase. To assess the effect of these six amino acid residues on cofactor activity, we created recombinant fa...

  19. Bacterial wall products induce downregulation of vascular endothelial growth factor receptors on endothelial cells via a CD14-dependent mechanism: implications for surgical wound healing.

    LENUS (Irish Health Repository)

    Power, C

    2012-02-03

    INTRODUCTION: Vascular endothelial growth factor (VEGF) is a potent mitogenic cytokine which has been identified as the principal polypeptide growth factor influencing endothelial cell (EC) migration and proliferation. Ordered progression of these two processes is an absolute prerequisite for initiating and maintaining the proliferative phase of wound healing. The response of ECs to circulating VEGF is determined by, and directly proportional to, the functional expression of VEGF receptors (KDR\\/Flt-1) on the EC surface membrane. Systemic sepsis and wound contamination due to bacterial infection are associated with significant retardation of the proliferative phase of wound repair. The effects of the Gram-negative bacterial wall components lipopolysaccharide (LPS) and bacterial lipoprotein (BLP) on VEGF receptor function and expression are unknown and may represent an important biological mechanism predisposing to delayed wound healing in the presence of localized or systemic sepsis. MATERIALS AND METHODS: We designed a series of in vitro experiments investigating this phenomenon and its potential implications for infective wound repair. VEGF receptor density on ECs in the presence of LPS and BLP was assessed using flow cytometry. These parameters were assessed in hypoxic conditions as well as in normoxia. The contribution of CD14 was evaluated using recombinant human (rh) CD14. EC proliferation in response to VEGF was quantified in the presence and absence of LPS and BLP. RESULTS: Flow cytometric analysis revealed that LPS and BLP have profoundly repressive effects on VEGF receptor density in normoxic and, more pertinently, hypoxic conditions. The observed downregulation of constitutive and inducible VEGF receptor expression on ECs was not due to any directly cytotoxic effect of LPS and BLP on ECs, as measured by cell viability and apoptosis assays. We identified a pivotal role for soluble\\/serum CD14, a highly specific bacterial wall product receptor, in

  20. Research on the Influencing Factors of Rural Low-carbon Economic Development and Government Regulation

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    This paper analyses the main factors causing sluggish development of rural low-carbon economy in China as follows:the rural energy structure is irrational;the infrastructure and technology are relatively backward;system of laws,regulations and policy is not sound;fund-raising mechanism develops slowly;farmers’ low-carbon awareness and ability are limited.On the basis of these unfavorable factors,from the perspective of government regulation,feasible strategies are put forward in line with the actual situation of rural low-carbon economic development in China.

  1. Emotion Regulation in Sexually Abused Preschoolers: The Contribution of Parental Factors.

    Science.gov (United States)

    Langevin, Rachel; Hébert, Martine; Allard-Dansereau, Claire; Bernard-Bonnin, Anne-Claude

    2016-04-01

    Child sexual abuse (CSA) is associated with emotion regulation deficits in childhood. Parents play a crucial role in the development of emotion regulation in their children, especially at younger ages. Close to 50% of mothers of sexually abused children report having been sexually victimized themselves as children. They are consequently at risk of experiencing significant distress following the disclosure of sexual abuse of their child. Parents' distress could interfere with their ability to provide support and to foster development of emotion regulation in their children. The aim of the present study was to explore the relationship of parental factors (history of sexual victimization in childhood and the current level of distress) to sexually abused preschoolers' emotion regulation competencies. Emotion regulation was assessed in 153 preschoolers by their parents with the Emotion Regulation Checklist; 75 of these children were abused (14 boys); 78 were not abused (21 boys) and were part of a comparison group. Parents reported their level of distress using the Psychiatric Symptom Index. Results indicated that parental factors contributed to some dimensions of preschoolers' emotion regulation (namely displays of underregulation of emotion) above and beyond children's victimization status and gender (Cohen's ƒ(2) = .15). Identifying parental distress and history of sexual victimization as positively associated with emotional dysregulation in preschool children victims of CSA has important research and clinical implications. PMID:26915665

  2. PreImplantation factor (PIF*) regulates systemic immunity and targets protective regulatory and cytoskeleton proteins.

    Science.gov (United States)

    Barnea, Eytan R; Hayrabedyan, Soren; Todorova, Krassimira; Almogi-Hazan, Osnat; Or, Reuven; Guingab, Joy; McElhinney, James; Fernandez, Nelson; Barder, Timothy

    2016-07-01

    Secreted by viable embryos, PIF is expressed by the placenta and found in maternal circulation. It promotes implantation and trophoblast invasion, achieving systemic immune homeostasis. Synthetic PIF successfully transposes endogenous PIF features to non-pregnant immune and transplant models. PIF affects innate and activated PBMC cytokines and genes expression. We report that PIF targets similar proteins in CD14+, CD4+ and CD8+ cells instigating integrated immune regulation. PIF-affinity chromatography followed by mass-spectrometry, pathway and heatmap analysis reveals that SET-apoptosis inhibitor, vimentin, myosin-9 and calmodulin are pivotal for immune regulation. PIF acts on macrophages down-stream of LPS (lipopolysaccharide-bacterial antigen) CD14/TLR4/MD2 complex, targeting myosin-9, thymosin-α1 and 14-3-3eta. PIF mainly targets platelet aggregation in CD4+, and skeletal proteins in CD8+ cells. Pathway analysis demonstrates that PIF targets and regulates SET, tubulin, actin-b, and S100 genes expression. PIF targets systemic immunity and has a short circulating half-life. Collectively, PIF targets identified; protective, immune regulatory and cytoskeleton proteins reveal mechanisms involved in the observed efficacy against immune disorders. PMID:26944449

  3. The use of efficiency improvement factor in regulation of income frame for electric grid companies

    International Nuclear Information System (INIS)

    An efficiency improvement parameter is an integrated part of a family of regulatory mechanisms often denoted as RPI-X. The present report examines what factors are to be included in the efficiency improvement factor. A theoretical derivation shows that the income growth in the regulated sector shall be limited to the price growth of the economy corrected for a factor-X that consists of four components: a productivity component, a price component, a component that accounts for differences in exogenic costs in the regulated sector and the rest of the economy, and a activity level component. The productivity component accounts for the differences in productivity changes between the two sectors, and the price component accounts for the differences in the prices of factor inputs

  4. Deciphering the components that coordinately regulate virulence factors of the soft rot pathogen Dickeya dadantii.

    Science.gov (United States)

    Wu, Xiaogang; Zeng, Quan; Koestler, Benjamin J; Waters, Christopher M; Sundin, George W; Hutchins, William; Yang, Ching-Hong

    2014-10-01

    The bacterial soft rot pathogen Dickeya dadantii utilizes the type III secretion system (T3SS) to suppress host defense responses, and secretes pectate lyase (Pel) to disintegrate the plant cell wall. A transposon mutagenesis fluorescence-activated cell sorting screen was used to identify mutants with altered promoter activities of the T3SS pilus gene hrpA. Several insertion mutations, resulting in changes in hrpA expression, were mapped to a new locus, opgGH, which encodes the gene cluster responsible for osmoregulated periplasmic glucan (OPG) synthesis proteins. Our data showed that OPG was involved in T3SS and Pel regulation by altering the expression of the regulatory small RNA RsmB. Through genome searching, the mechanism of two novel regulatory components, the RcsCD-RcsB phosphorelay and CsrD on OPG and the rsmB gene, was further investigated. The Rcs phosphorelay and OPG inversely regulated rsmB at transcriptional and post-transcriptional levels, respectively. CsrD exhibited dual functionality in T3SS and Pel regulation by manipulating levels of RsmB RNA and cyclic diguanylate monophosphate (c-di-GMP). CsrD positively regulated the promoter activity of the rsmB gene but negatively controlled RsmB RNA at the post-transcriptional level via OpgGH. In addition, CsrD contains both GGDEF and EAL domains but acted as a c-di-GMP phosphodiesterase. When the expression of the csrD gene was induced, CsrD regulated T3SS expression and Pel production through controlling intracellular c-di-GMP levels. PMID:25180688

  5. Quorum-sensing regulation governs bacterial adhesion, biofilm development, and host colonization in Pantoea stewartii subspecies stewartii.

    Science.gov (United States)

    Koutsoudis, Maria D; Tsaltas, Dimitrios; Minogue, Timothy D; von Bodman, Susanne B

    2006-04-11

    The phytopathogenic bacterium Pantoea stewartii subsp. stewartii synthesizes stewartan exo/capsular polysaccharide (EPS) in a cell density-dependent manner governed by the EsaI/EsaR quorum-sensing (QS) system. This study analyzes biofilm development and host colonization of the WT and QS regulatory mutant strains of P. stewartii. First, we show that the cell density-dependent synthesis of stewartan EPS, governed by the EsaI/EsaR QS system, is required for proper bacterial adhesion and development of spatially defined, 3D biofilms. Second, a nonvirulent mutant lacking the esaI gene adheres strongly to surfaces and develops densely packed, less structurally defined biofilms in vitro. This strain appears to be arrested in a low cell density developmental mode. Exposure of this strain to exogenous N-acyl-homoserine lactone counteracts this adhesion phenotype. Third, QS mutants lacking the EsaR repressor attach poorly to surfaces and form amorphous biofilms heavily enmeshed in excess EPS. Fourth, the WT strain disseminates efficiently within the xylem, primarily in a basipetal direction. In contrast, the two QS mutant strains remain largely localized at the site of infection. Fifth, and most significantly, epifluorescence microscopic imaging of infected leaf tissue and excised xylem vessels reveals that the bacteria colonize the xylem with unexpected specificity, particularly toward the annular rings and spiral secondary wall thickenings of protoxylem, as opposed to indiscriminate growth to fill the xylem lumen. These observations are significant to bacterial plant pathogenesis in general and may reveal targets for disease control. PMID:16585516

  6. Activating transcription factor 3 is not up-regulated in hypospadias patients in Japan

    OpenAIRE

    Toshiaki Takahashi; Akihiro Shimotakahara; Katsumi Miyahara; Geoffrey J Lane; Atsuyuki Yamataka

    2013-01-01

    Background: The aetiology of hypospadias is largely uncharacterized. Some of the researchers have advocated that activating transcription factor 3 (ATF3), an oestrogen-responsive transcription factor, is up-regulated in patients with hypospadias. The purpose is to evaluate the universality of this fact; we studied the expression of ATF3 protein in prepuce tissue obtained from hypospadias and phimosis patients living in metropolitan Tokyo. Materials and Methods: Prepuce tissue was obtained fro...

  7. Regulation of human cardiac KCNQ1/KCNE1 channel by epidermal growth factor receptor kinase

    OpenAIRE

    Dong, MQ; Sun, HY; Tang, Q.; Tse, HF; Lau, CP; Li, GR

    2010-01-01

    The aim of the present study was to investigate whether/how the recombinant human cardiac I Ks could be regulated by epidermal growth factor receptor kinase in HEK 293 cells stably expressing hKCNQ1/hKCNE1 genes using the approaches of perforated patch clamp technique, immunoprecipitation and Western blot analysis. It was found that the broad spectrum isoflavone tyrosine kinase inhibitor genistein and the selective epidermal growth factor receptor kinase inhibitor tyrphostin AG556 suppressed ...

  8. Genetic interaction between GROWTH-REGULATING FACTOR and CUP-SHAPED COTYLEDON in organ separation

    OpenAIRE

    Lee, Byung Ha; Jeon, Jae Og; Lee, Myeong Min; Kim, Jeong Hoe

    2015-01-01

    The Arabidopsis thaliana GROWTH-REGULATING FACTOR (GRF) gene family comprises 9 members and encodes a class of transcription factors. We previously demonstrated that GRF genes played an essential role in formation of the boundary region between cotyledons, since their loss-of-function mutants developed fused cotyledons. Our present study shows that the grf mutants display fused floral organs as well. Such fusion phenotypes of embryonic and post-embryonic floral organs are highly reminiscent o...

  9. Crystallization and preliminary crystallographic analysis of the bacterial capsule assembly-regulating tyrosine phosphatases Wzb of Escherichia coli and Cps4B of Streptococcus pneumoniae

    International Nuclear Information System (INIS)

    The crystallization is reported of two bacterial tyrosine phosphatases which belong to different enzyme families despite their ability to catalyse identical reactions. Bacterial tyrosine kinases and their cognate phosphatases are key players in the regulation of capsule assembly and thus are important virulence determinants of these bacteria. Examples of the kinase/phosphatase pairing are found in Gram-negative bacteria such as Escherichia coli (Wzc and Wzb) and in Gram-positive bacteria such as Streptococcus pneumoniae (CpsCD and CpsB). Although Wzb and Cps4B are both predicted to dephosphorylate the C-terminal tyrosine cluster of their cognate tyrosine kinase, they appear on the basis of protein sequence to belong to quite different enzyme classes. Recombinant purified proteins Cps4B of S. pneumoniae TIGR4 and Wzb of E. coli K-30 have been crystallized. Wzb crystals belonged to space-group family P3x21 and diffracted to 2.7 Å resolution. Crystal form I of Cps4B belonged to space-group family P4x212 and diffracted to 2.8 Å resolution; crystal form II belonged to space group P212121 and diffracted to 1.9 Å resolution

  10. Insulin growth factors regulate the mitotic cycle in cultured rat sympathetic neuroblasts

    International Nuclear Information System (INIS)

    While neuronal mitosis is uniquely restricted to early development, the underlying regulation remains to be defined. The authors have now developed a dissociated, embryonic sympathetic neuron culture system that uses fully defined medium in which cells enter the mitotic cycle. The cultured cells expressed two neuronal traits, tyrosine hydroxylase and the neuron-specific 160-kDa neurofilament subunit protein, but were devoid of glial fibrillary acidic protein, a marker for non-myelin-forming Schwann cells in ganglia. Approximately one-third of the tyrosine hydroxylase-positive cells synthesized DNA in culture, specifically incorporating [3H]thymidine into their nuclei. They used this system to define factors regulating the mitotic cycle in sympathetic neuroblasts. Members of the insulin family of growth factors, including insulin and insulin-like growth factors I and II, regulated DNA synthesis in the presumptive neuroblasts. Insulin more than doubled the proportion of tyrosine hydroxylase-positive cells entering the mitotic cycle, as indicated by autoradiography of [3H]thymidine incorporation into nuclei. Scintillation spectrometry was an even more sensitive index of DNA synthesis. In contrast, the trophic protein nerve growth factor exhibited no mitogenic effect, suggesting that the mitogenic action of insulin growth factors is highly specific. The observations are discussed in the context of the detection of insulin growth factors and receptors in the developing brain

  11. Pasteurella pneumotropica evades the human complement system by acquisition of the complement regulators factor H and C4BP.

    Directory of Open Access Journals (Sweden)

    Alfredo Sahagún-Ruiz

    Full Text Available Pasteurella pneumotropica is an opportunist Gram negative bacterium responsible for rodent pasteurellosis that affects upper respiratory, reproductive and digestive tracts of mammals. In animal care facilities the presence of P. pneumotropica causes severe to lethal infection in immunodeficient mice, being also a potential source for human contamination. Indeed, occupational exposure is one of the main causes of human infection by P. pneumotropica. The clinical presentation of the disease includes subcutaneous abscesses, respiratory tract colonization and systemic infections. Given the ability of P. pneumotropica to fully disseminate in the organism, it is quite relevant to study the role of the complement system to control the infection as well as the possible evasion mechanisms involved in bacterial survival. Here, we show for the first time that P. pneumotropica is able to survive the bactericidal activity of the human complement system. We observed that host regulatory complement C4BP and Factor H bind to the surface of P. pneumotropica, controlling the activation pathways regulating the formation and maintenance of C3-convertases. These results show that P. pneumotropica has evolved mechanisms to evade the human complement system that may increase the efficiency by which this pathogen is able to gain access to and colonize inner tissues where it may cause severe infections.

  12. Use of bacterial two-hybrid system to investigate the molecular interaction between the regulators NifA and NifL of Enterobacter cloacae

    Institute of Scientific and Technical Information of China (English)

    廖贡献; 俞冠翘; 沈善炯; 朱家璧

    2002-01-01

    Expression of the nitrogen fixation (nif ) genes is tightly regulated by two proteins NifA and NifL in the (-subdivision of the proteobacteria. NifA is a transcriptional activator, which can be inactivated by NifL in the presence of oxygen or excess fixed nitrogen. A direct interaction between E. cloacae NifL and NifA was detected using the bacterial two-hybrid system. This interaction was accelerated in the presence of fixed nitrogen, while oxygen had no effect. NifL proteins, with their C-terminus being deleted, completely lost the ability to interact with NifA. The data suggest that the C-terminal domain of NifL acts as a sensor of the nitrogen status of the cell and mediates interaction with NifA.

  13. Photoautotrophic symbiont and geography are major factors affecting highly structured and diverse bacterial communities in the lichen microbiome

    Energy Technology Data Exchange (ETDEWEB)

    Hodkinson, Brendan P [ORNL; Gottel, Neil R [ORNL; Schadt, Christopher Warren [ORNL; Lutzoni, Francois [Duke University

    2011-01-01

    Although common knowledge dictates that the lichen thallus is formed solely by a fungus (mycobiont) that develops a symbiotic relationship with an alga and/or cyanobacterium (photobiont), the non-photoautotrophic bacteria found in lichen microbiomes are increasingly regarded as integral components of lichen thalli. For this study, comparative analyses were conducted on lichen-associated bacterial communities to test for effects of photobiont-types (i.e. green algal vs. cyanobacterial), mycobiont-types and large-scale spatial distances (from tropical to arctic latitudes). Amplicons of the 16S (SSU) rRNA gene were examined using both Sanger sequencing of cloned fragments and barcoded pyrosequencing. Rhizobiales is typically the most abundant and taxonomically diverse order in lichen microbiomes; however, overall bacterial diversity in lichens is shown to be much higher than previously reported. Members of Acidobacteriaceae, Acetobacteraceae, Brucellaceae and sequence group LAR1 are the most commonly found groups across the phylogenetically and geographically broad array of lichens examined here. Major bacterial community trends are significantly correlated with differences in large-scale geography, photobiont-type and mycobiont-type. The lichen as a microcosm represents a structured, unique microbial habitat with greater ecological complexity and bacterial diversity than previously appreciated and can serve as a model system for studying larger ecological and evolutionary principles.

  14. Factor structure of the Self-Regulation Questionnaire (SRQ) at Spanish universities.

    Science.gov (United States)

    Pichardo, Carmen; Justicia, Fernando; de la Fuente, Jesús; Martínez-Vicente, José Manuel; Berbén, Ana B G

    2014-01-01

    The Self-Regulation Questionnaire (SRQ) has been used in psychology research during the last decade. The instrument has been used in a variety of life domains: psychological well-being, dispositional happiness, depressive symptoms and career adaptability. This investigation studies the factor structure and internal consistency of the SRQ, extracting a short version in the Spanish context and examining its relation to academic variables (self-regulated learning and grades). The analysis started from a version with 63 items, representing seven conceptual dimensions. This version was administered to a sample of 834 students from Education and Psychology. The data from the above-mentioned sample were randomly divided into two sets, each containing 50% of the students (n = 417): exploratory and confirmatory. In the exploratory sample, exploratory factor analysis findings suggested a more parsimonious measurement model, with 17 items and 4 first-order factors. The confirmatory sample was used in the confirmatory factor analysis. The results show evidence for the internal consistency of the Short Self-Regulation Questionnaire (SSRQ) in the Spanish context, with indices greater than .90 and errors around .05. Regarding academic variables, both versions are related to self-regulated learning (r = .40, p < .01) and students' grades (r = .15, p < .01). Differences from other studies done in North America are discussed, as well as similarities to a study from North-West University (in South Africa). PMID:26054362

  15. Nkx factors specifically regulate expression of Hedgehog receptor isoforms in early embryonic development

    Science.gov (United States)

    BACKGROUND: NK homeobox family members are tissue-specific transcription factors that regulate developmental genes. Homozygous disruption of Nkx3.2 produces severe developmental defects of the axial skeleton, skull, spleen, and stomach. Murine mutation of Nkx2.5 results in death at E9 with defects i...

  16. Sigma factor RpoN (σ54) regulates pilE transcription in commensal Neisseria elongata.

    Science.gov (United States)

    Rendón, María A; Hockenberry, Alyson M; McManus, Steven A; So, Magdalene

    2013-10-01

    Human-adapted Neisseria includes two pathogens, Neisseria gonorrhoeae and Neisseria meningitidis, and at least 13 species of commensals that colonize many of the same niches as the pathogens. The Type IV pilus plays an important role in the biology of pathogenic Neisseria. In these species, Sigma factor RpoD (σ(70)), Integration Host Factor, and repressors RegF and CrgA regulate transcription of pilE, the gene encoding the pilus structural subunit. The Type IV pilus is also a strictly conserved trait in commensal Neisseria. We present evidence that a different mechanism regulates pilE transcription in commensals. Using Neisseria elongata as a model, we show that Sigma factor RpoN (σ(54)), Integration Host Factor, and an activator we name Npa regulate pilE transcription. Taken in context with previous reports, our findings indicate pilE regulation switched from an RpoN- to an RpoD-dependent mechanism as pathogenic Neisseria diverged from commensals during evolution. Our findings have implications for the timing of Tfp expression and Tfp-mediated host cell interactions in these two groups of bacteria. PMID:23899162

  17. Regulation of the epithelial calcium channel TRPV5 by extracellular factors.

    NARCIS (Netherlands)

    Topala, C.N.; Bindels, R.J.M.; Hoenderop, J.G.J.

    2007-01-01

    PURPOSE OF REVIEW: Recent studies have greatly increased our knowledge concerning the regulation of renal calcium handling. This review focuses on newly identified calciotropic factors present in the pro-urine and the mechanisms by which they control the transient receptor potential channel vanilloi

  18. AGC kinases regulate phosphorylation and activation of eukaryotic translation initiation factor 4B

    NARCIS (Netherlands)

    van Gorp, A. G. M.; van der Vos, K. E.; Brenkman, A. B.; Bremer, A.; van den Broek, N.; Zwartkruis, F.; Hershey, J. W.; Burgering, B. M. T.; Calkhoven, C. F.; Coffer, P. J.

    2009-01-01

    Eukaryotic translation initiation factor 4B (eIF4B) plays a critical role during the initiation of protein synthesis and its activity can be regulated by multiple phosphorylation events. In a search for novel protein kinase B (PKB/c-akt) substrates, we identified eIF4B as a potential target. Using a

  19. DMPD: Nuclear factor-kappaB: activation and regulation during toll-like receptorsignaling. [Dynamic Macrophage Pathway CSML Database

    Lifescience Database Archive (English)

    Full Text Available 17349209 Nuclear factor-kappaB: activation and regulation during toll-like receptor...signaling. Carmody RJ, Chen YH. Cell Mol Immunol. 2007 Feb;4(1):31-41. (.png) (.svg) (.html) (.csml) Show Nuclear factor...-kappaB: activation and regulation during toll-like receptorsignaling. PubmedID 17349209 Title Nuclear factor

  20. Mechanically stimulated bone cells secrete paracrine factors that regulate osteoprogenitor recruitment, proliferation, and differentiation

    International Nuclear Information System (INIS)

    Bone formation requires the recruitment, proliferation and osteogenic differentiation of mesenchymal progenitors. A potent stimulus driving this process is mechanical loading, yet the signalling mechanisms underpinning this are incompletely understood. The objective of this study was to investigate the role of the mechanically-stimulated osteocyte and osteoblast secretome in coordinating progenitor contributions to bone formation. Initially osteocytes (MLO-Y4) and osteoblasts (MC3T3) were mechanically stimulated for 24hrs and secreted factors within the conditioned media were collected and used to evaluate mesenchymal stem cell (MSC) and osteoblast recruitment, proliferation and osteogenesis. Paracrine factors secreted by mechanically stimulated osteocytes significantly enhanced MSC migration, proliferation and osteogenesis and furthermore significantly increased osteoblast migration and proliferation when compared to factors secreted by statically cultured osteocytes. Secondly, paracrine factors secreted by mechanically stimulated osteoblasts significantly enhanced MSC migration but surprisingly, in contrast to the osteocyte secretome, inhibited MSC proliferation when compared to factors secreted by statically cultured osteoblasts. A similar trend was observed in osteoblasts. This study provides new information on mechanically driven signalling mechanisms in bone and highlights a contrasting secretome between cells at different stages in the bone lineage, furthering our understanding of loading-induced bone formation and indirect biophysical regulation of osteoprogenitors. - Highlights: • Physically stimulated osteocytes secrete factors that regulate osteoprogenitors. • These factors enhance recruitment, proliferation and osteogenic differentiation. • Physically stimulated osteoblasts secrete factors that also regulate progenitors. • These factors enhance recruitment but inhibit proliferation of osteoprogenitors. • This study highlights a contrasting

  1. Mechanically stimulated bone cells secrete paracrine factors that regulate osteoprogenitor recruitment, proliferation, and differentiation

    Energy Technology Data Exchange (ETDEWEB)

    Brady, Robert T. [Tissue Engineering Research Group, Dept. of Anatomy, Royal College of Surgeons in Ireland (Ireland); Trinity Centre for Bioengineering, School of Engineering, Trinity College Dublin (Ireland); Advanced Materials and BioEngineering Research Centre (AMBER), Trinity College Dublin & Royal College of Surgeons in Ireland (Ireland); Dept. of Mechanical, Aeronautical and Biomedical Engineering, University of Limerick (Ireland); O' Brien, Fergal J. [Tissue Engineering Research Group, Dept. of Anatomy, Royal College of Surgeons in Ireland (Ireland); Trinity Centre for Bioengineering, School of Engineering, Trinity College Dublin (Ireland); Advanced Materials and BioEngineering Research Centre (AMBER), Trinity College Dublin & Royal College of Surgeons in Ireland (Ireland); Hoey, David A., E-mail: david.hoey@ul.ie [Trinity Centre for Bioengineering, School of Engineering, Trinity College Dublin (Ireland); Dept. of Mechanical, Aeronautical and Biomedical Engineering, University of Limerick (Ireland); The Centre for Applied Biomedical Engineering Research, University of Limerick (Ireland); Materials & Surface Science Institute, University of Limerick (Ireland)

    2015-03-27

    Bone formation requires the recruitment, proliferation and osteogenic differentiation of mesenchymal progenitors. A potent stimulus driving this process is mechanical loading, yet the signalling mechanisms underpinning this are incompletely understood. The objective of this study was to investigate the role of the mechanically-stimulated osteocyte and osteoblast secretome in coordinating progenitor contributions to bone formation. Initially osteocytes (MLO-Y4) and osteoblasts (MC3T3) were mechanically stimulated for 24hrs and secreted factors within the conditioned media were collected and used to evaluate mesenchymal stem cell (MSC) and osteoblast recruitment, proliferation and osteogenesis. Paracrine factors secreted by mechanically stimulated osteocytes significantly enhanced MSC migration, proliferation and osteogenesis and furthermore significantly increased osteoblast migration and proliferation when compared to factors secreted by statically cultured osteocytes. Secondly, paracrine factors secreted by mechanically stimulated osteoblasts significantly enhanced MSC migration but surprisingly, in contrast to the osteocyte secretome, inhibited MSC proliferation when compared to factors secreted by statically cultured osteoblasts. A similar trend was observed in osteoblasts. This study provides new information on mechanically driven signalling mechanisms in bone and highlights a contrasting secretome between cells at different stages in the bone lineage, furthering our understanding of loading-induced bone formation and indirect biophysical regulation of osteoprogenitors. - Highlights: • Physically stimulated osteocytes secrete factors that regulate osteoprogenitors. • These factors enhance recruitment, proliferation and osteogenic differentiation. • Physically stimulated osteoblasts secrete factors that also regulate progenitors. • These factors enhance recruitment but inhibit proliferation of osteoprogenitors. • This study highlights a contrasting

  2. Preparation and preliminary X-ray diffraction analysis of crystals of bacterial flagellar sigma factor σ28 in complex with the σ28-binding region of its antisigma factor, FlgM

    International Nuclear Information System (INIS)

    A complex of E. coli flagellar and chemotaxis-specific sigma factor σ28 bound to the σ28-binding region of its antisigma factor FlgM was crystallized. Diffraction data were collected to a resolution of 2.7 Å. The sigma 28 kDa (σ28) factor is a transcription factor specific for the expression of bacterial flagellar and chemotaxis genes. Its antisigma factor, FlgM, binds σ28 factor and inhibits its activity as a transcription factor. In this study, crystals of the complex between Escherichia coli σ28 and the C-terminal σ28-binding region of FlgM were obtained. The crystals belong to space group P3121 or P3221, with unit-cell parameters a = b = 106.7 (2), c = 51.74 (3) Å, containing one complex in the crystallographic asymmetric unit. An X-ray intensity data set was collected to a resolution of 2.7 Å

  3. Ste12 and Ste12-Like Proteins, Fungal Transcription Factors Regulating Development and Pathogenicity ▿

    OpenAIRE

    Wong Sak Hoi, Joanne; Dumas, Bernard

    2010-01-01

    Ste12 and Ste12-like proteins are transcription factors found exclusively in the fungal kingdom. In the yeast model Saccharomyces cerevisiae, where the first member was identified, Ste12p was shown to regulate mating and invasive/pseudohyphal growth. In recent literature, there have been several reports of Ste12-like factors in multiple fungal systems, yeasts or filamentous fungi, with saprophytic or parasitic life-styles. In all these models, Ste12 and Ste12-like factors are involved in the ...

  4. On the use of risk-informed regulation including organizational factors

    International Nuclear Information System (INIS)

    Risk-Informed Regulation (RIR) can be applied by using Probabilistic Safety Assessment (PSA) as a basic tool. Traditionally, PSA methodology encompasses the calculation of failure probabilities of Structures, Systems and Components (SSCs) and direct associated human errors. However, there are indirect causes related to human failures, associated with Organizational Factors, which are normally not included in fault trees, that may influence plant risk evaluation. This paper discusses on possible applications of RIR and on Organizational Factors. It also presents a classification of Angra-1 NPP unresolved issues, aiming a future inclusion of these factors into a PSA calculation. (author)

  5. In Vitro Whole Genome DNA Binding Analysis of the Bacterial Replication Initiator and Transcription Factor DnaA.

    Directory of Open Access Journals (Sweden)

    Janet L Smith

    2015-05-01

    Full Text Available DnaA, the replication initiation protein in bacteria, is an AAA+ ATPase that binds and hydrolyzes ATP and exists in a heterogeneous population of ATP-DnaA and ADP-DnaA. DnaA binds cooperatively to the origin of replication and several other chromosomal regions, and functions as a transcription factor at some of these regions. We determined the binding properties of Bacillus subtilis DnaA to genomic DNA in vitro at single nucleotide resolution using in vitro DNA affinity purification and deep sequencing (IDAP-Seq. We used these data to identify 269 binding regions, refine the consensus sequence of the DnaA binding site, and compare the relative affinity of binding regions for ATP-DnaA and ADP-DnaA. Most sites had a slightly higher affinity for ATP-DnaA than ADP-DnaA, but a few had a strong preference for binding ATP-DnaA. Of the 269 sites, only the eight strongest binding ones have been observed to bind DnaA in vivo, suggesting that other cellular factors or the amount of available DnaA in vivo restricts DnaA binding to these additional sites. Conversely, we found several chromosomal regions that were bound by DnaA in vivo but not in vitro, and that the nucleoid-associated protein Rok was required for binding in vivo. Our in vitro characterization of the inherent ability of DnaA to bind the genome at single nucleotide resolution provides a backdrop for interpreting data on in vivo binding and regulation of DnaA, and is an approach that should be adaptable to many other DNA binding proteins.

  6. Effects of interactions of auxin-producing bacteria and bacterial-feeding nematodes on regulation of peanut growths.

    Science.gov (United States)

    Xu, Li; Xu, Wensi; Jiang, Ying; Hu, Feng; Li, Huixin

    2015-01-01

    The influences of an IAA (indole-3-acetic acid)-producing bacterium (Bacillus megaterium) and two bacterial-feeding nematodes (Cephalobus sp. or Mesorhabditis sp.) on the growth of peanut (Arachis hypogaea L. cv. Haihua 1) after various durations of time were investigated in natural soils. The addition of bacteria and nematodes and incubation time all significantly affected plant growth, plant root growth, plant nutrient concentrations, soil nutrient concentrations, soil microorganisms and soil auxin concentration. The addition of nematodes caused greater increases in these indices than those of bacteria, while the addition of the combination of bacteria and nematodes caused further increases. After 42-day growth, the increases in soil respiration differed between the additions of two kinds of nematodes because of differences in their life strategies. The effects of the bacteria and nematodes on the nutrient and hormone concentrations were responsible for the increases in plant growth. These results indicate the potential for promoting plant growth via the addition of nematodes and bacteria to soil. PMID:25867954

  7. Effects of interactions of auxin-producing bacteria and bacterial-feeding nematodes on regulation of peanut growths.

    Directory of Open Access Journals (Sweden)

    Li Xu

    Full Text Available The influences of an IAA (indole-3-acetic acid-producing bacterium (Bacillus megaterium and two bacterial-feeding nematodes (Cephalobus sp. or Mesorhabditis sp. on the growth of peanut (Arachis hypogaea L. cv. Haihua 1 after various durations of time were investigated in natural soils. The addition of bacteria and nematodes and incubation time all significantly affected plant growth, plant root growth, plant nutrient concentrations, soil nutrient concentrations, soil microorganisms and soil auxin concentration. The addition of nematodes caused greater increases in these indices than those of bacteria, while the addition of the combination of bacteria and nematodes caused further increases. After 42-day growth, the increases in soil respiration differed between the additions of two kinds of nematodes because of differences in their life strategies. The effects of the bacteria and nematodes on the nutrient and hormone concentrations were responsible for the increases in plant growth. These results indicate the potential for promoting plant growth via the addition of nematodes and bacteria to soil.

  8. Sox2, a key factor in the regulation of pluripotency and neural differentiation

    Institute of Scientific and Technical Information of China (English)

    Shuchen; Zhang; Wei; Cui

    2014-01-01

    Sex determining region Y-box 2(Sox2), a member of the SoxB1 transcription factor family, is an important transcriptional regulator in pluripotent stem cells(PSCs). Together with octamer-binding transcription factor 4 and Nanog, they co-operatively control gene expression in PSCs and maintain their pluripotency. Furthermore, Sox2 plays an essential role in somatic cell reprogram-ming, reversing the epigenetic configuration of differ-entiated cells back to a pluripotent embryonic state. In addition to its role in regulation of pluripotency, Sox2 is also a critical factor for directing the differentiation of PSCs to neural progenitors and for maintaining the properties of neural progenitor stem cells. Here, we review recent findings concerning the involvement of Sox2 in pluripotency, somatic cell reprogramming and neural differentiation as well as the molecular mecha-nisms underlying these roles.

  9. Krüppel-like factor 4, a novel transcription factor regulates microglial activation and subsequent neuroinflammation

    Directory of Open Access Journals (Sweden)

    Das Sulagna

    2010-10-01

    Full Text Available Abstract Background Activation of microglia, the resident macrophages of the central nervous system (CNS, is the hallmark of neuroinflammation in neurodegenerative diseases and other pathological conditions associated with CNS infection. The activation of microglia is often associated with bystander neuronal death. Nuclear factor-κB (NF-κB is one of the important transcription factors known to be associated with microglial activation which upregulates the expression of inducible nitric oxide synthase (iNOS, cyclooxygenase-2 (Cox-2 and other pro-inflammatory cytokines. Recent studies have focused on the role of Krüppel-like factor 4 (Klf4, one of the zinc-finger transcription factors, in mediating inflammation. However, these studies were limited to peripheral system and its role in CNS is not understood. Our studies focused on the possible role of Klf4 in mediating CNS inflammation. Methods For in vitro studies, mouse microglial BV-2 cell lines were treated with 500 ng/ml Salmonella enterica lipopolysacchride (LPS. Brain tissues were isolated from BALB/c mice administered with 5 mg/kg body weight of LPS. Expressions of Klf4, Cox-2, iNOS and pNF-κB were evaluated using western blotting, quantitative real time PCR, and reverse transcriptase polymerase chain reactions (RT-PCRs. Klf4 knockdown was carried out using SiRNA specific for Klf4 mRNA and luciferase assays and electromobility shift assay (EMSA were performed to study the interaction of Klf4 to iNOS promoter elements in vitro. Co-immunoprecipitation of Klf4 and pNF-κB was done in order to study a possible interaction between the two transcription factors. Results LPS stimulation increased Klf4 expression in microglial cells in a time- and dose-dependent manner. Knockdown of Klf4 resulted in decreased levels of the pro-inflammatory cytokines TNF-α, MCP-1 and IL-6, along with a significant decrease in iNOS and Cox-2 expression. NO production also decreased as a result of Klf4 knockdown

  10. Macrophage migration inhibitory factor regulates interleukin-6 production by facilitating nuclear factor-kappa B activation during Vibrio vulnificus infection

    Directory of Open Access Journals (Sweden)

    Choi Pui-Ching

    2010-10-01

    Full Text Available Abstract Background Patients infected with Vibrio vulnificus (V. vulnificus show severe inflammatory responses characterised by the upregulation of proinflammatory cytokines. Macrophage migration inhibitory factor (MIF, an upstream proinflammatory regulator, increases the inflammation caused by sepsis. Whether MIF regulates responses to V. vulnificus infection and the actual mechanism by which V. vulnificus initiates these MIF-modulated proinflammatory cytokines remain unclear. Results MIF increased inflammation during V. vulnificus infection in vivo. In V. vulnificus-infected mice, MIF was produced earlier than tumour necrosis factor (TNF-α and interleukin (IL-6 and was expressed in a time-dependent manner. ISO-1 ((S, R-3-(4-hydroxyphenyl-4,5-dihydro-5-isoxazole acetic acid methyl ester, a small-molecule inhibitor of MIF, significantly decreased IL-6, IL-8, and TNF-α production in a time- and dose-dependent manner in human peripheral blood cells infected with V. vulnificus. The induction of IL-6, IL-8, and TNF-α production by V. vulnificus infection was mediated via the NF-κB- and p38 MAPK-regulated pathways but not via the Akt pathway. ISO-1-treated human peripheral blood cells showed lower V. vulnificus-induced NF-κB activation, IL-6 mRNA expression, and IκB phosphorylation, but they did not show lower p38 MAPK activation. Conclusions We conclude that MIF regulates V. vulnificus-induced IL-6 production via NF-κB activation and that p38 MAPK activation in V. vulnificus infection is not MIF dependent.

  11. Novel TetR family transcriptional factor regulates expression of multiple transport-related genes and affects rifampicin resistance in Mycobacterium smegmatis

    OpenAIRE

    Huicong Liu; Min Yang; Zheng-Guo He

    2016-01-01

    Transport-related genes significantly affect bacterial antibiotic resistance. However, the effects of these genes and their regulation of bacterial drug resistance in several mycobacterial species, including the fast-growing Mycobacterium smegmatis, the pathogen M. tuberculosis and M. avium have not been clearly characterized. We identified Ms4022 (MSMEG_4022) as a novel TetR family regulator that activates the expression of seven transport-related genes and affects drug resistance in M. smeg...

  12. RNA-guided transcriptional regulation in planta via synthetic dCas9-based transcription factors

    KAUST Repository

    Piatek, Agnieszka

    2014-11-14

    Targeted genomic regulation is a powerful approach to accelerate trait discovery and development in agricultural biotechnology. Bacteria and archaea use clustered regularly interspaced short palindromic repeats (CRISPRs) and CRISPR-associated (Cas) regulatory systems for adaptive molecular immunity against foreign nucleic acids introduced by invading phages and conjugative plasmids. The type II CRISPR/Cas system has been adapted for genome editing in many cell types and organisms. A recent study used the catalytically inactive Cas9 (dCas9) protein combined with guide-RNAs (gRNAs) as a DNA-targeting platform to modulate gene expression in bacterial, yeast, and human cells. Here, we modified this DNA-targeting platform for targeted transcriptional regulation in planta by developing chimeric dCas9-based transcriptional activators and repressors. To generate transcriptional activators, we fused the dCas9 C-terminus with the activation domains of EDLL and TAL effectors. To generate a transcriptional repressor, we fused the dCas9 C-terminus with the SRDX repression domain. Our data demonstrate that dCas9 fusion with the EDLL activation domain (dCas9:EDLL) and the TAL activation domain (dCas9:TAD), guided by gRNAs complementary to selected promoter elements, induce strong transcriptional activation on Bs3

  13. Transforming Growth Factor β Regulates P-Body Formation through Induction of the mRNA Decay Factor Tristetraprolin

    OpenAIRE

    Blanco, Fernando F.; Sanduja, Sandhya; Deane, Natasha G; Blackshear, Perry J.; Dixon, Dan A.

    2014-01-01

    Transforming growth factor β (TGF-β) is a potent growth regulator and tumor suppressor in normal intestinal epithelium. Likewise, epithelial cell growth is controlled by rapid decay of growth-related mRNAs mediated through 3′ untranslated region (UTR) AU-rich element (ARE) motifs. We demonstrate that treatment of nontransformed intestinal epithelial cells with TGF-β inhibited ARE-mRNA expression. This effect of TGF-β was promoted through increased assembly of cytoplasmic RNA processing (P) bo...

  14. Bacterial neuraminidase increases IL-8 production in lung epithelial cells via NF-κB-dependent pathway

    International Nuclear Information System (INIS)

    Bacterial neuraminidase, a sialic acid-degrading enzyme, is one of the virulent factors produced in pathogenic bacteria like as other bacterial components. However little is known about whether bacterial neuraminidase can initiate or modify a cellular response, such as cytokine production, in epithelial cells at infection and inflammation. We demonstrate here that bacterial neuraminidase, but not heat-inactivated neuraminidase, up-regulates expression of interleukin-8 (IL-8) mRNA and protein in lung epithelial A549 and NCI-H292 cells. We also show that bacterial neuraminidase significantly up-regulates IL-8 promoter activity as well as nuclear factor-kappaB (NF-κB) reporter activity. Moreover, inhibition of NF-κB signaling suppressed IL-8 mRNA expression induced by bacterial neuraminidase. Taken together, desialylation-induced IL-8 production in lung epithelial cells may play an important role in infection-associated inflammatory events.

  15. Age-related differences in emotion regulation strategies: Examining the role of contextual factors.

    Science.gov (United States)

    Schirda, Brittney; Valentine, Thomas R; Aldao, Amelia; Prakash, Ruchika Shaurya

    2016-09-01

    Increasing age is characterized by greater positive affective states. However, there is mixed evidence on the implementation of emotion regulation strategies across the life span. To clarify the discrepancies in the literature, we examined the modulating influence of contextual factors in understanding emotion regulation strategy use in older and young adults. Forty-eight older adults and forty-nine young adults completed a retrospective survey inquiring about the use of emotion regulation strategies in emotion-eliciting situations experienced over the preceding 2 weeks. We used factor analysis to establish clusters of emotion regulation strategies, resulting in cognitive strategies, acceptance, and maladaptive strategies. Overall, we found context-dependent age-related differences in emotion regulation strategy use. Specifically, older adults reported greater use of acceptance than young adults in situations of moderate intensity and in situations that evoke anxiety and sadness. In addition, older adults reported using maladaptive strategies to a lesser extent in high- and moderate-intensity situations and in situations that elicit anxiety and sadness when compared with young adults. There were no age-related differences in the use of cognitive strategies across contexts. Older adults, compared to young adults, reported less use of maladaptive strategies and greater use of acceptance than young adults, which suggests that the enhanced emotional functioning observed later in life may be due to a shift in strategy implementation. (PsycINFO Database Record PMID:27570980

  16. Zinc finger transcription factors displaced SREBP proteins as the major Sterol regulators during Saccharomycotina evolution.

    Directory of Open Access Journals (Sweden)

    Sarah L Maguire

    2014-01-01

    Full Text Available In most eukaryotes, including the majority of fungi, expression of sterol biosynthesis genes is regulated by Sterol-Regulatory Element Binding Proteins (SREBPs, which are basic helix-loop-helix transcription activators. However, in yeasts such as Saccharomyces cerevisiae and Candida albicans sterol synthesis is instead regulated by Upc2, an unrelated transcription factor with a Gal4-type zinc finger. The SREBPs in S. cerevisiae (Hms1 and C. albicans (Cph2 have lost a domain, are not major regulators of sterol synthesis, and instead regulate filamentous growth. We report here that rewiring of the sterol regulon, with Upc2 taking over from SREBP, likely occurred in the common ancestor of all Saccharomycotina. Yarrowia lipolytica, a deep-branching species, is the only genome known to contain intact and full-length orthologs of both SREBP (Sre1 and Upc2. Deleting YlUPC2, but not YlSRE1, confers susceptibility to azole drugs. Sterol levels are significantly reduced in the YlUPC2 deletion. RNA-seq analysis shows that hypoxic regulation of sterol synthesis genes in Y. lipolytica is predominantly mediated by Upc2. However, YlSre1 still retains a role in hypoxic regulation; growth of Y. lipolytica in hypoxic conditions is reduced in a Ylupc2 deletion and is abolished in a Ylsre1/Ylupc2 double deletion, and YlSre1 regulates sterol gene expression during hypoxia adaptation. We show that YlSRE1, and to a lesser extent YlUPC2, are required for switching from yeast to filamentous growth in hypoxia. Sre1 appears to have an ancestral role in the regulation of filamentation, which became decoupled from its role in sterol gene regulation by the arrival of Upc2 in the Saccharomycotina.

  17. Tumor necrosis factor beta and ultraviolet radiation are potent regulators of human keratinocyte ICAM-1 expression

    International Nuclear Information System (INIS)

    Intercellular adhesion molecule-1 (ICAM-1) functions as a ligand of leukocyte function-associated antigen-1 (LFA-1), as well as a receptor for human picorna virus, and its regulation thus affects various immunologic and inflammatory reactions. The weak, constitutive ICAM-1 expression on human keratinocytes (KC) can be up-regulated by cytokines such as interferon-gamma (IFN gamma) and tumor necrosis factor alpha (TNF alpha). In order to further examine the regulation of KC ICAM-1 expression, normal human KC or epidermoid carcinoma cells (KB) were incubated with different cytokines and/or exposed to ultraviolet (UV) radiation. Subsequently, ICAM-1 expression was monitored cytofluorometrically using a monoclonal anti-ICAM-1 antibody. Stimulation of cells with recombinant human (rh) interleukin (IL) 1 alpha, rhIL-4, rhIL-5, rhIL-6, rh granulocyte/macrophage colony-stimulating factor (GM-CSF), rh interferon alpha (rhIFN alpha), and rh transforming growth factor beta (TGF beta) did not increase ICAM-1 surface expression. In contrast, rhTNF beta significantly up-regulated ICAM-1 expression in a time- and dose-dependent manner. Moreover, the combination of rhTNF beta with rhIFN gamma increased the percentage of ICAM-1-positive KC synergistically. This stimulatory effect of rhTNF beta was further confirmed by the demonstration that rhTNF beta was capable of markedly enhancing ICAM-1 mRNA expression in KC. Finally, exposure of KC in vitro to sublethal doses of UV radiation (0-100 J/m2) prior to cytokine (rhIFN tau, rhTNF alpha, rhTNF beta) stimulation inhibited ICAM-1 up-regulation in a dose-dependent fashion. These studies identify TNF beta and UV light as potent regulators of KC ICAM-1 expression, which may influence both attachment and detachment of leukocytes and possibly viruses to KC

  18. Regulation of vascular endothelial growth factor expression by homeodomain-interacting protein kinase-2

    Directory of Open Access Journals (Sweden)

    D'Orazi Gabriella

    2008-07-01

    Full Text Available Abstract Background Homeodomain-interacting protein kinase-2 (HIPK2 plays an essential role in restraining tumor progression as it may regulate, by itself or within multiprotein complexes, many proteins (mainly transcription factors involved in cell growth and apoptosis. This study takes advantage of the recent finding that HIPK2 may repress the β-catenin transcription activity. Thus, we investigated whether HIPK2 overexpression may down-regulate vascular endothelial growth factor (VEGF levels (a β-catenin target gene and the role of β-catenin in this regulation, in order to consider HIPK2 as a tool for novel anti-tumoral therapeutical approaches. Methods The regulation of VEGF expression by HIPK2 was evaluated by using luciferase assay with VEGF reporter construct, after overexpression of the β-catenin transcription factor. Relative quantification of VEGF and β-catenin mRNAs were assessed by reverse-transcriptase-PCR (RT-PCR analyses, following HIPK2 overexpression, while β-catenin protein levels were evaluated by western immunoblotting. Results HIPK2 overexpression in tumor cells downregulated VEGF mRNA levels and VEGF promoter activity. The VEGF downregulation was partly depending on HIPK2-mediated β-catenin regulation. Thus, HIPK2 could induce β-catenin protein degradation that was prevented by cell treatment with proteasome inhibitor MG132. The β-catenin degradation was dependent on HIPK2 catalytic activity and independent of p53 and glycogen synthase kinase 3β (GSK-3β activities. Conclusion These results suggest that VEGF might be a target of HIPK2, at least in part, through regulation of β-catenin activity. These findings support the function of HIPK2 as tumor suppressor and hypothesise a role for HIPK2 as antiangiogenic tool in tumor therapy approaches.

  19. Improving protein delivery of fibroblast growth factor-2 from bacterial inclusion bodies used as cell culture substrates

    OpenAIRE

    Seras Franzoso, Joaquin; Peebo, Karl; Garcia Fruitós, Elena; Vázquez Gómez, Esther; Rinas, Ursula; Villaverde Corrales, Antonio

    2014-01-01

    Altres ajuts: We are indebted CIBER de Bioingeniería, Biomateriales y Nanomedicina (CIBER-BBN, Spain) for funding our research on inclusion bodies. Bacterial inclusion bodies (IBs) have recently been used to generate biocompatible cell culture interfaces, with diverse effects on cultured cells such as cell adhesion enhancement, stimulation of cell growth or induction of mesenchymal stem cell differentiation. Additionally, novel applications of IBs as sustained protein delivery systems with...

  20. Spontaneous elaboration of transforming growth factor beta suppresses host defense against bacterial infection in autoimmune MRL/lpr mice

    OpenAIRE

    1994-01-01

    Infection with gram-negative and gram-positive bacteria remains a leading cause of death in patients with systemic lupus erythematosis (SLE), even in the absence of immunosuppressive therapy. To elucidate the mechanisms that underly the increased risk of infection observed in patients with systemic autoimmunity, we have investigated host defense against bacterial infection in a murine model of autoimmunity, the MRL/Mp-lpr/lpr (MRL/lpr) mouse. Our previous study implicated transforming growth ...

  1. Computational identification of a p38SAPK regulated transcription factor network required for tumor cell quiescence

    OpenAIRE

    Adam, Alejandro P.; George, Ajish; Schewe, Denis; Bragado, Paloma; Iglesias, Bibiana V.; Ranganathan, Aparna C.; Kourtidis, Antonis; Conklin, Douglas S.; Julio A Aguirre-Ghiso

    2009-01-01

    The stress activated kinase p38 plays key roles in tumor suppression and induction of tumor cell dormancy. However, the mechanisms behind these functions remain poorly understood. Using computational tools we identified a transcription factor (TF) network regulated by p38α/β and required for human squamous carcinoma cell quiescence in vivo. We found that p38 transcriptionally regulates a core network of 46 genes that includes 16 TFs. Activation of p38 induced the expression of the TFs p53 and...

  2. Situational Awareness: Regulation of the Myb Transcription Factor in Differentiation, the Cell Cycle and Oncogenesis

    International Nuclear Information System (INIS)

    This review summarizes the mechanisms that control the activity of the c-Myb transcription factor in normal cells and tumors, and discusses how c-Myb plays a role in the regulation of the cell cycle. Oncogenic versions of c-Myb contribute to the development of leukemias and solid tumors such as adenoid cystic carcinoma, breast cancer and colon cancer. The activity and specificity of the c-Myb protein seems to be controlled through changes in protein-protein interactions, so understanding how it is regulated could lead to the development of novel therapeutic strategies

  3. Situational Awareness: Regulation of the Myb Transcription Factor in Differentiation, the Cell Cycle and Oncogenesis

    Energy Technology Data Exchange (ETDEWEB)

    George, Olivia L.; Ness, Scott A., E-mail: sness@salud.unm.edu [Department of Internal Medicine, Section of Molecular Medicine, University of New Mexico Health Sciences Center, MSC07 4025-CRF 121, 1 University of New Mexico, Albuquerque, NM 87131 (United States)

    2014-10-02

    This review summarizes the mechanisms that control the activity of the c-Myb transcription factor in normal cells and tumors, and discusses how c-Myb plays a role in the regulation of the cell cycle. Oncogenic versions of c-Myb contribute to the development of leukemias and solid tumors such as adenoid cystic carcinoma, breast cancer and colon cancer. The activity and specificity of the c-Myb protein seems to be controlled through changes in protein-protein interactions, so understanding how it is regulated could lead to the development of novel therapeutic strategies.

  4. Mga2 Transcription Factor Regulates an Oxygen-responsive Lipid Homeostasis Pathway in Fission Yeast.

    Science.gov (United States)

    Burr, Risa; Stewart, Emerson V; Shao, Wei; Zhao, Shan; Hannibal-Bach, Hans Kristian; Ejsing, Christer S; Espenshade, Peter J

    2016-06-01

    Eukaryotic lipid synthesis is oxygen-dependent with cholesterol synthesis requiring 11 oxygen molecules and fatty acid desaturation requiring 1 oxygen molecule per double bond. Accordingly, organisms evaluate oxygen availability to control lipid homeostasis. The sterol regulatory element-binding protein (SREBP) transcription factors regulate lipid homeostasis. In mammals, SREBP-2 controls cholesterol biosynthesis, whereas SREBP-1 controls triacylglycerol and glycerophospholipid biosynthesis. In the fission yeast Schizosaccharomyces pombe, the SREBP-2 homolog Sre1 regulates sterol homeostasis in response to changing sterol and oxygen levels. However, notably missing is an SREBP-1 analog that regulates triacylglycerol and glycerophospholipid homeostasis in response to low oxygen. Consistent with this, studies have shown that the Sre1 transcription factor regulates only a fraction of all genes up-regulated under low oxygen. To identify new regulators of low oxygen adaptation, we screened the S. pombe nonessential haploid deletion collection and identified 27 gene deletions sensitive to both low oxygen and cobalt chloride, a hypoxia mimetic. One of these genes, mga2, is a putative transcriptional activator. In the absence of mga2, fission yeast exhibited growth defects under both normoxia and low oxygen conditions. Mga2 transcriptional targets were enriched for lipid metabolism genes, and mga2Δ cells showed disrupted triacylglycerol and glycerophospholipid homeostasis, most notably with an increase in fatty acid saturation. Indeed, addition of exogenous oleic acid to mga2Δ cells rescued the observed growth defects. Together, these results establish Mga2 as a transcriptional regulator of triacylglycerol and glycerophospholipid homeostasis in S. pombe, analogous to mammalian SREBP-1. PMID:27053105

  5. A novel receptor – ligand pathway for entry of Francisella tularensis in monocyte-like THP-1 cells: interaction between surface nucleolin and bacterial elongation factor Tu

    Directory of Open Access Journals (Sweden)

    Charbit Alain

    2008-09-01

    Full Text Available Abstract Background Francisella tularensis, the causative agent of tularemia, is one of the most infectious human bacterial pathogens. It is phagocytosed by immune cells, such as monocytes and macrophages. The precise mechanisms that initiate bacterial uptake have not yet been elucidated. Participation of C3, CR3, class A scavenger receptors and mannose receptor in bacterial uptake have been already reported. However, contribution of an additional, as-yet-unidentified receptor for F. tularensis internalization has been suggested. Results We show here that cell-surface expressed nucleolin is a receptor for Francisella tularensis Live Vaccine Strain (LVS and promotes LVS binding and infection of human monocyte-like THP-1 cells. The HB-19 pseudopeptide that binds specifically carboxy-terminal RGG domain of nucleolin inhibits LVS binding and infection of monocyte-like THP-1 cells. In a pull-down assay, elongation factor Tu (EF-Tu, a GTP-binding protein involved in protein translation, usually found in cytoplasm, was recovered among LVS bacterial membrane proteins bound on RGG domain of nucleolin. A specific polyclonal murine antibody was raised against recombinant LVS EF-Tu. By fluorescence and electron microscopy experiments, we found that a fraction of EF-Tu could be detected at the bacterial surface. Anti-EF-Tu antibodies reduced LVS binding to monocyte-like THP-1 cells and impaired infection, even in absence of complement and complement receptors. Interaction between EF-Tu and nucleolin was illustrated by two different pull-down assays using recombinant EF-Tu proteins and either RGG domain of nucleolin or cell solubilized nucleolin. Discussion Altogether, our results demonstrate that the interaction between surface nucleolin and its bacterial ligand EF-Tu plays an important role in Francisella tularensis adhesion and entry process and may therefore facilitate invasion of host tissues. Since phagosomal escape and intra-cytosolic multiplication of

  6. A multi-scale model of hepcidin promoter regulation reveals factors controlling systemic iron homeostasis.

    Directory of Open Access Journals (Sweden)

    Guillem Casanovas

    2014-01-01

    Full Text Available Systemic iron homeostasis involves a negative feedback circuit in which the expression level of the peptide hormone hepcidin depends on and controls the iron blood levels. Hepcidin expression is regulated by the BMP6/SMAD and IL6/STAT signaling cascades. Deregulation of either pathway causes iron-related diseases such as hemochromatosis or anemia of inflammation. We quantitatively analyzed how BMP6 and IL6 control hepcidin expression. Transcription factor (TF phosphorylation and reporter gene expression were measured under co-stimulation conditions, and the promoter was perturbed by mutagenesis. Using mathematical modeling, we systematically analyzed potential mechanisms of cooperative and competitive promoter regulation by the transcription factors, and experimentally validated the model predictions. Our results reveal that hepcidin cross-regulation primarily occurs by combinatorial transcription factor binding to the promoter, whereas signaling crosstalk is insignificant. We find that the presence of two BMP-responsive elements enhances the steepness of the promoter response towards the iron-sensing BMP signaling axis, which promotes iron homeostasis in vivo. IL6 co-stimulation reduces the promoter sensitivity towards the BMP signal, because the SMAD and STAT transcription factors compete for recruiting RNA polymerase to the transcription start site. This may explain why inflammatory signals disturb iron homeostasis in anemia of inflammation. Taken together, our results reveal why the iron homeostasis circuit is sensitive to perturbations implicated in disease.

  7. Modelling Transcriptional Regulation with a Mixture of Factor Analyzers and Variational Bayesian Expectation Maximization

    Directory of Open Access Journals (Sweden)

    Kuang Lin

    2009-01-01

    Full Text Available Understanding the mechanisms of gene transcriptional regulation through analysis of high-throughput postgenomic data is one of the central problems of computational systems biology. Various approaches have been proposed, but most of them fail to address at least one of the following objectives: (1 allow for the fact that transcription factors are potentially subject to posttranscriptional regulation; (2 allow for the fact that transcription factors cooperate as a functional complex in regulating gene expression, and (3 provide a model and a learning algorithm with manageable computational complexity. The objective of the present study is to propose and test a method that addresses these three issues. The model we employ is a mixture of factor analyzers, in which the latent variables correspond to different transcription factors, grouped into complexes or modules. We pursue inference in a Bayesian framework, using the Variational Bayesian Expectation Maximization (VBEM algorithm for approximate inference of the posterior distributions of the model parameters, and estimation of a lower bound on the marginal likelihood for model selection. We have evaluated the performance of the proposed method on three criteria: activity profile reconstruction, gene clustering, and network inference.

  8. SUMOylation can regulate the activity of ETS-like transcription factor 4.

    Science.gov (United States)

    Kaikkonen, Sanna; Makkonen, Harri; Rytinki, Miia; Palvimo, Jorma J

    2010-08-01

    ETS-like transcription factor 4 (ELK4) (a.k.a. serum response factor accessory protein 1) belongs to the ternary complex factor (TCF) subfamily of E twenty-six (ETS) domain transcription factors. Compared to the other TCF subfamily members, ELK1 and ELK3 (NET), there is limited information of the mechanisms regulating the ELK4 activity. Here, we show that the ELK4 can be covalently modified (SUMOylated) by small ubiquitin-related modifier (SUMO) 1 protein, an important regulator of signaling and transcription. SUMOylation of ELK4 was reversed by SUMO-specific proteases (SENP) 1 and 2 and stimulated by SUMO E3 ligase PIAS3. Conserved lysine residue 167 that is located in the NET inhibitory domain of ELK4 was identified as the main site of SUMO-1 conjugation. Interestingly, mutation of the K167 disrupting the SUMOylation markedly enhanced the transcriptional activity of the ELK4, but weakened its repressive function on c-fos promoter. In conclusion, our results suggest that covalent modification by SUMO-1 can regulate the activity of ELK4, contributing to the transcriptional repression by the ELK4. PMID:20637912

  9. Analysis of the LacI family regulators of Erwinia chrysanthemi 3937, involvement in the bacterial phytopathogenicity.

    Science.gov (United States)

    Van Gijsegem, Frédérique; Wlodarczyk, Aleksandra; Cornu, Amandine; Reverchon, Sylvie; Hugouvieux-Cotte-Pattat, Nicole

    2008-11-01

    Analysis of the regulators of the LacI family was performed in order to identify those potentially involved in pathogenicity of Erwinia chrysanthemi (Dickeya dadantii). Among the 18 members of the LacI family, the function of 11 members is either known or predicted and only 7 members have, as yet, no proposed function. Inactivation of these seven genes, called lfaR, lfbR, lfcR, lfdR, lfeR, lffR, and lfgR, demonstrated that four of them are important for plant infection. The lfaR and lfcR mutants showed a reduced virulence on chicory, Saintpaulia sp., and Arabidopsis. The lfeR mutant showed a reduced virulence on Arabidopsis. The lfdR mutant was more efficient than the wild-type strain in initiating maceration on Saintpaulia sp. The genetic environment of each regulator was examined to detect adjacent genes potentially involved in a common function. Construction of transcriptional fusions in these neighboring genes demonstrated that five regulators, LfaR, LfcR, LfeR, LffR, and LfgR, act as repressors of adjacent genes. Analysis of these fusions also indicated that the genes controlled by LfaR, LfcR, LfgR, and LffR are expressed during plant infection. Moreover, addition of crude plant extracts to culture medium demonstrated that the expression of the LfaR- and LfgR-controlled genes is specifically induced by plant components. PMID:18842096

  10. Inter- and intra-combinatorial regulation by transcription factors and microRNAs

    Directory of Open Access Journals (Sweden)

    Chang Joseph T

    2007-10-01

    Full Text Available Abstract Background MicroRNAs (miRNAs are a novel class of non-coding small RNAs. In mammalian cells, miRNAs repress the translation of messenger RNAs (mRNAs or degrade mRNAs. miRNAs play important roles in development and differentiation, and they are also implicated in aging, and oncogenesis. Predictions of targets of miRNAs suggest that they may regulate more than one-third of all genes. The overall functions of mammalian miRNAs remain unclear. Combinatorial regulation by transcription factors alone or miRNAs alone offers a wide range of regulatory programs. However, joining transcriptional and post-transcriptional regulatory mechanisms enables higher complexity regulatory programs that in turn could give cells evolutionary advantages. Investigating coordinated regulation of genes by miRNAs and transcription factors (TFs from a statistical standpoint is a first step that may elucidate some of their roles in various biological processes. Results Here, we studied the nature and scope of coordination among regulators from the transcriptional and miRNA regulatory layers in the human genome. Our findings are based on genome wide statistical assessment of regulatory associations ("interactions" among the sets of predicted targets of miRNAs and sets of putative targets of transcription factors. We found that combinatorial regulation by transcription factor pairs and miRNA pairs is much more abundant than the combinatorial regulation by TF-miRNA pairs. In addition, many of the strongly interacting TF-miRNA pairs involve a subset of master TF regulators that co-regulate genes in coordination with almost any miRNA. Application of standard measures for evaluating the degree of interaction between pairs of regulators show that strongly interacting TF-miRNA, TF-TF or miRNA-miRNA pairs tend to include TFs or miRNAs that regulate very large numbers of genes. To correct for this potential bias we introduced an additional Bayesian measure that incorporates

  11. Blocking transforming growth factor- receptor signaling down-regulates transforming growth factor-β1 autoproduction in keloid fibroblasts

    Institute of Scientific and Technical Information of China (English)

    刘伟; 蔡泽浩; 王丹茹; 武小莉; 崔磊; 商庆新; 钱云良; 曹谊林

    2002-01-01

    Objective: To study transforming growth factor-β1(TGF-β1) autoproduction in keloid fibroblasts and theregulation effect of blocking TGF-β intracellular signalingon rhTGF-β1 autoproduction.Methods: Keloid fibroblasts cultured in vitro weretreated with either rhTGF-β1 (5 ng/ml ) or recombinantadenovirus containing a truncated type II TGF-β receptorgene (50 pfu/cell ). Their effects of regulating geneexpression of TGF-β1 and its receptor I and II wereobserved with Northern blot.Results: rhTGF-β1 up-regulated the gene expressionof TGF-β1 and receptor I, but not receptor II. Over-expression of the truncated receptor II down-regulated thegene expression of TGF-β1 and its receptor I, but notreceptor II.Conclusions: TGF-β1 autoproduction was observed inkeloid fibroblasts. Over-expression of the truncated TGF-βreceptor H decreased TGF-β1 autoproduction via blockingTGF-β receptor signaling.

  12. A Burkholderia pseudomallei type III secreted protein, BopE, facilitates bacterial invasion of epithelial cells and exhibits guanine nucleotide exchange factor activity

    OpenAIRE

    M.P. Stevens; Friebel, A; Taylor, L A; Wood, M W; Brown, P. J.; Hardt, W D; Galyov, E E

    2003-01-01

    We report the characterization of BopE, a type III secreted protein that is encoded adjacent to the Burkholderia pseudomallei bsa locus and is homologous to Salmonella enterica SopE/SopE2. Inactivation of bopE impaired bacterial entry into HeLa cells, indicating that BopE facilitates invasion. Consistent with this notion, BopE expressed in eukaryotic cells induced rearrangements in the subcortical actin cytoskeleton, and purified BopE exhibited guanine nucleotide exchange factor activity for ...

  13. Regulation of angiogenesis in human skeletal muscle with specific focus on pro- angiogenic and angiostatic factors

    DEFF Research Database (Denmark)

    Høier, Birgitte

    important. Furthermore, it appears that the pro-angiogeinc factors, eNOS, MMP9, Ang2, and Tie-2 and the angiostatic factors, TIMP-1 and TSP-1 play an important part in modulation the angiogenic response to acute exercise and training in human skeletal muscle thus determining if capillary growth occurs or...... VEGF vesicles being a mechanism for regulating VEGF secretion in response to exercise. Furthermore, the exercise-induced increase in VEGF secretion was shown to be mediated in part through adenosine which is released during contraction, and its receptor A2B which activates the MAPK pathway and in part...... was studied in peripheral arterial disease. Vascular endothelial growth factor (VEGF) is the most important factor in exercise-induced angiogenesis and is located primarily in muscle cells but also in endothelial cells, pericytes, and in the extracellular matrix. VEGF protein secretion to the...

  14. The Hv NAC6 transcription factor: a positive regulator of penetration resistance in barley and Arabidopsis

    DEFF Research Database (Denmark)

    Jensen, Michael Krogh; Rung, Jesper Henrik; Gregersen, Per Langkjaer;

    2007-01-01

    Pathogens induce the expression of many genes encoding plant transcription factors, though specific knowledge of the biological function of individual transcription factors remains scarce. NAC transcription factors are encoded in plants by a gene family with proposed functions in both abiotic and...... biotic stress adaptation, as well as in developmental processes. In this paper, we provide convincing evidence that a barley NAC transcription factor has a direct role in regulating basal defence. The gene transcript was isolated by differential display from barley leaves infected with the biotrophic...... towards virulent Bgh. Complementing the effect of HvNAC6 gene silencing, transient overexpression of HvNAC6 increases the occurrence of penetration resistant cells towards Bgh attack. Quantitative RT-PCR shows the early and transient induction of HvNAC6 in barley epidermis upon Bgh infection. Additionally...

  15. The Secret Life of Tethers: The Role of Tethering Factors in SNARE Complex Regulation.

    Science.gov (United States)

    Dubuke, Michelle L; Munson, Mary

    2016-01-01

    Trafficking in eukaryotic cells is a tightly regulated process to ensure correct cargo delivery to the proper destination organelle or plasma membrane. In this review, we focus on how the vesicle fusion machinery, the SNARE complex, is regulated by the interplay of the multisubunit tethering complexes (MTC) with the SNAREs and Sec1/Munc18 (SM) proteins. Although these factors are used in different stages of membrane trafficking, e.g., Golgi to plasma membrane transport vs. vacuolar fusion, and in a variety of diverse eukaryotic cell types, many commonalities between their functions are being revealed. We explore the various protein-protein interactions and findings from functional reconstitution studies in order to highlight both their common features and the differences in their modes of regulation. These studies serve as a starting point for mechanistic explorations in other systems. PMID:27243006

  16. Trefoil factor 3 (TFF3 expression is regulated by insulin and glucose

    Directory of Open Access Journals (Sweden)

    Girolamo Jose Barrera Roa

    2013-04-01

    Full Text Available Introduction: Trefoil factors are effector molecules in gastrointestinal tract physiology. They are classified into three groups: the gastric peptides (TFF1, spasmolytic peptide (TFF2 and intestinal trefoil factor (TFF3. Previous studies have shown that trefoil factors are located and expressed in human endocrine pancreas suggesting that TFF3 play a role in: a pancreatic cells migration, b β-cell mitosis, and c pancreatic cells regeneration. We speculated that the presence of TFF3 in pancreas, could be associated to a possible regulation mechanism by insulin and glucose. To date, there are not reports whether the unbalance in carbohydrate metabolism observed in diabetes could affect the production or expression of TFF3.Methods: We determined the TFF3 levels and expression by immunoassay (ELISA and semi-quantitative RT-PCR technique respectively, of intestinal epithelial cells (HT-29 treated with glucose and insulin. Also,Real Time-PCR (RTq-PCR was done.Results: Increasing concentrations of glucose improved TFF3 expression and these levels were further elevated after insulin treatment. Insulin treatment also led to the up-regulation of human sodium/glucose transporter 1 (hSGLT1, which further increases intracellular glucose levels. Finally, we investigated theTFF3 levels in serum of diabetes mellitus type 1 (T1DM and healthy patients. Here we shown that serum TFF3 levels were down-regulated in T1DM and this levels were up-regulated after insulin treatment. Also, the TFF3 levels of healthy donors were up-regulated 2 h after breakfast.Conclusion: Our fi ndings suggest for the fi rst time that insulin signaling is important for TFF3 optimal expression in serum and intestinal epithelial cells.

  17. Transcriptional Factor PU.1 Regulates Decidual C1q Expression in Early Pregnancy in Human.

    Science.gov (United States)

    Madhukaran, Shanmuga Priyaa; Kishore, Uday; Jamil, Kaiser; Teo, Boon Heng Dennis; Choolani, Mahesh; Lu, Jinhua

    2015-01-01

    C1q is the first recognition subcomponent of the complement classical pathway, which in addition to being synthesized in the liver, is also expressed by macrophages and dendritic cells (DCs). Trophoblast invasion during early placentation results in accumulation of debris that triggers the complement system. Hence, both early and late components of the classical pathway are widely distributed in the placenta and decidua. In addition, C1q has recently been shown to significantly contribute to feto-maternal tolerance, trophoblast migration, and spiral artery remodeling, although the exact mechanism remains unknown. Pregnancy in mice, genetically deficient in C1q, mirrors symptoms similar to that of human preeclampsia. Thus, regulated complement activation has been proposed as an essential requirement for normal successful pregnancy. Little is known about the molecular pathways that regulate C1q expression in pregnancy. PU.1, an Ets-family transcription factor, is required for the development of hematopoietic myeloid lineage immune cells, and its expression is tissue-specific. Recently, PU.1 has been shown to regulate C1q gene expression in DCs and macrophages. Here, we have examined if PU.1 transcription factor regulates decidual C1q expression. We used immune-histochemical analysis, PCR, and immunostaining to localize and study the gene expression of PU.1 transcription factor in early human decidua. PU.1 was highly expressed at gene and protein level in early human decidual cells including trophoblast and stromal cells. Surprisingly, nuclear as well as cytoplasmic PU.1 expression was observed. Decidual cells with predominantly nuclear PU.1 expression had higher C1q expression. It is likely that nuclear and cytoplasmic PU.1 localization has a role to play in early pregnancy via regulating C1q expression in the decidua during implantation. PMID:25762996

  18. Mcm1p-Induced DNA Bending Regulates the Formation of Ternary Transcription Factor Complexes

    OpenAIRE

    Lim, Fei-Ling; Hayes, Andrew; West, Adam G; Pic-Taylor, Aline; Darieva, Zoulfia; Morgan, Brian A; Oliver, Stephen G.; Sharrocks, Andrew D.

    2003-01-01

    The yeast MADS-box transcription factor Mcm1p plays an important regulatory role in several diverse cellular processes. In common with a subset of other MADS-box transcription factors, Mcm1p elicits substantial DNA bending. However, the role of protein-induced bending by MADS-box proteins in eukaryotic gene regulation is not understood. Here, we demonstrate an important role for Mcm1p-mediated DNA bending in determining local promoter architecture and permitting the formation of ternary trans...

  19. Krüppel-Like Transcription Factor 13 Regulates T Lymphocyte Survival In Vivo1

    OpenAIRE

    Zhou, Meixia; McPherson, Lisa; Feng, Dongdong; Song, An; Dong, Chen; Lyu, Shu-Chen; Zhou, Lu; Shi, Xiaoyan; Ahn, Yong-Tae; Wang, Demin; Clayberger, Carol; Krensky, Alan M.

    2007-01-01

    Krüppel-like transcription factor (KLF)13, previously shown to regulate RANTES expression in vitro, is a member of the Krüppel-like family of transcription factors that controls many growth and developmental processes. To ascertain the function of KLF13 in vivo, Klf13-deficient mice were generated by gene targeting. As expected, activated T lymphocytes from Klf13−/− mice show decreased RANTES expression. However, these mice also exhibit enlarged thymi and spleens. TUNEL, as well as spontaneou...

  20. Protamine sulfate down-regulates thrombin generation by inhibiting factor V activation.

    LENUS (Irish Health Repository)

    Ni Ainle, Fionnuala

    2009-08-20

    Protamine sulfate is a positively charged polypeptide widely used to reverse heparin-induced anticoagulation. Paradoxically, prospective randomized trials have shown that protamine administration for heparin neutralization is associated with increased bleeding, particularly after cardiothoracic surgery with cardiopulmonary bypass. The molecular mechanism(s) through which protamine mediates this anticoagulant effect has not been defined. In vivo administration of pharmacologic doses of protamine to BALB\\/c mice significantly reduced plasma thrombin generation and prolonged tail-bleeding time (from 120 to 199 seconds). Similarly, in pooled normal human plasma, protamine caused significant dose-dependent prolongations of both prothrombin time and activated partial thromboplastin time. Protamine also markedly attenuated tissue factor-initiated thrombin generation in human plasma, causing a significant decrease in endogenous thrombin potential (41% +\\/- 7%). As expected, low-dose protamine effectively reversed the anticoagulant activity of unfractionated heparin in plasma. However, elevated protamine concentrations were associated with progressive dose-dependent reduction in thrombin generation. To assess the mechanism by which protamine mediates down-regulation of thrombin generation, the effect of protamine on factor V activation was assessed. Protamine was found to significantly reduce the rate of factor V activation by both thrombin and factor Xa. Protamine mediates its anticoagulant activity in plasma by down-regulation of thrombin generation via a novel mechanism, specifically inhibition of factor V activation.

  1. Expression of the bacterial type III effector DspA/E in Saccharomyces cerevisiae down-regulates the sphingolipid biosynthetic pathway leading to growth arrest.

    Science.gov (United States)

    Siamer, Sabrina; Guillas, Isabelle; Shimobayashi, Mitsugu; Kunz, Caroline; Hall, Michael N; Barny, Marie-Anne

    2014-06-27

    Erwinia amylovora, the bacterium responsible for fire blight, relies on a type III secretion system and a single injected effector, DspA/E, to induce disease in host plants. DspA/E belongs to the widespread AvrE family of type III effectors that suppress plant defense responses and promote bacterial growth following infection. Ectopic expression of DspA/E in plant or in Saccharomyces cerevisiae is toxic, indicating that DspA/E likely targets a cellular process conserved between yeast and plant. To unravel the mode of action of DspA/E, we screened the Euroscarf S. cerevisiae library for mutants resistant to DspA/E-induced growth arrest. The most resistant mutants (Δsur4, Δfen1, Δipt1, Δskn1, Δcsg1, Δcsg2, Δorm1, and Δorm2) were impaired in the sphingolipid biosynthetic pathway. Exogenously supplied sphingolipid precursors such as the long chain bases (LCBs) phytosphingosine and dihydrosphingosine also suppressed the DspA/E-induced yeast growth defect. Expression of DspA/E in yeast down-regulated LCB biosynthesis and induced a rapid decrease in LCB levels, indicating that serine palmitoyltransferase (SPT), the first and rate-limiting enzyme of the sphingolipid biosynthetic pathway, was repressed. SPT down-regulation was mediated by dephosphorylation and activation of Orm proteins that negatively regulate SPT. A Δcdc55 mutation affecting Cdc55-PP2A protein phosphatase activity prevented Orm dephosphorylation and suppressed DspA/E-induced growth arrest. PMID:24828506

  2. The Canadian Natural Health Products (NHP regulations: industry perceptions and compliance factors

    Directory of Open Access Journals (Sweden)

    Boon Heather

    2006-05-01

    Full Text Available Abstract Background The use of natural health products, such as vitamins, minerals, and herbs, by Canadians has been increasing with time. As a result of consumer concern about the quality of these products, the Canadian Department of Health created the Natural Health Products (NHP Regulations. The new Canadian regulations raise questions about whether and how the NHP industry will be able to comply and what impact they will have on market structure. The objectives of this study were to explore who in the interview sample is complying with Canada's new NHP Regulations (i.e., submitted product licensing applications on time; and explore the factors that affect regulatory compliance. Methods Twenty key informant interviews were conducted with employees of the NHP industry. The structured interviews focused on the level of satisfaction with the Regulations and perceptions of compliance and non-compliance. Interviews were tape recorded and then transcribed verbatim. Data were independently coded, using qualitative content analysis. Team meetings were held after every three to four interviews to discuss emerging themes. Results The major finding of this study is that most (17 out of 20 companies interviewed were beginning to comply with the new regulatory regime. The factors that contribute to likelihood of regulatory compliance were: perceptions and knowledge of the regulations and business size. Conclusion The Canadian case can be instructive for other countries seeking to implement regulatory standards for natural health products. An unintended consequence of the Canadian NHP regulations may be the exit of smaller firms, leading to industry consolidation.

  3. An R2R3-MYB transcription factor regulates carotenoid pigmentation in Mimulus lewisii flowers.

    Science.gov (United States)

    Sagawa, Janelle M; Stanley, Lauren E; LaFountain, Amy M; Frank, Harry A; Liu, Chang; Yuan, Yao-Wu

    2016-02-01

    Carotenoids are yellow, orange, and red pigments that contribute to the beautiful colors and nutritive value of many flowers and fruits. The structural genes in the highly conserved carotenoid biosynthetic pathway have been well characterized in multiple plant systems, but little is known about the transcription factors that control the expression of these structural genes. By analyzing a chemically induced mutant of Mimulus lewisii through bulk segregant analysis and transgenic experiments, we have identified an R2R3-MYB, Reduced Carotenoid Pigmentation 1 (RCP1), as the first transcription factor that positively regulates carotenoid biosynthesis during flower development. Loss-of-function mutations in RCP1 lead to down-regulation of all carotenoid biosynthetic genes and reduced carotenoid content in M. lewisii flowers, a phenotype recapitulated by RNA interference in the wild-type background. Overexpression of this gene in the rcp1 mutant background restores carotenoid production and, unexpectedly, results in simultaneous decrease of anthocyanin production in some transgenic lines by down-regulating the expression of an activator of anthocyanin biosynthesis. Identification of transcriptional regulators of carotenoid biosynthesis provides the 'toolbox' genes for understanding the molecular basis of flower color diversification in nature and for potential enhancement of carotenoid production in crop plants via genetic engineering. PMID:26377817

  4. Transcriptional regulation of Wnt inhibitory factor-1 by Miz-1/c-Myc

    OpenAIRE

    Licchesi, JDF; Van Neste, L; Tiwari, VK; Cope, L; Lin, X.; Baylin, SB; Herman, JG

    2010-01-01

    The Wnt signaling pathway is capable of self-regulation through positive and negative feedback mechanisms. For example, the oncoprotein c-Myc, which is upregulated by Wnt signaling activity, participates in a positive feedback loop of canonical Wnt signaling through repression of Wnt antagonists DKK1 and SFRP1. In this study, we investigated the mechanism of Wnt inhibitory factor-1 (WIF-1) silencing. Mapping of CpG island methylation of the WIF-1 promoter reveals regional methylation (–295 to...

  5. The FOXO3a Transcription Factor Regulates Cardiac Myocyte Size Downstream of AKT Signaling*

    OpenAIRE

    Skurk, Carsten; Izumiya, Yasuhiro; Maatz, Henrike; Razeghi, Peter; Shiojima, Ichiro; Sandri, Marco; Sato, Kaori; Zeng, Ling; Schiekofer, Stephan; Pimentel, David; Lecker, Stewart; Taegtmeyer, Heinrich; Goldberg, Alfred L.; Walsh, Kenneth

    2005-01-01

    Although signaling mechanisms inducing cardiac hypertrophy have been extensively studied, little is known about the mechanisms that reverse cardiac hypertrophy. Here, we describe the existence of a similar Akt/forkhead signaling axis in cardiac myocytes in vitro and in vivo, which is regulated by insulin, insulin-like growth factor (IGF), stretch, pressure overload, and angiotensin II stimulation. FOXO3a gene transfer prevented both IGF and stretch-induced hypertrophy in rat neonatal cardiac ...

  6. The activity-dependent transcription factor NPAS4 regulates domain-specific inhibition

    OpenAIRE

    Bloodgood, Brenda L.; Sharma, Nikhil; Browne, Heidi Adlman; Trepman, Alissa Z.; Greenberg, Michael E.

    2013-01-01

    A heterogeneous population of inhibitory neurons controls the flow of information through a neural circuit1–3. Inhibitory synapses that form on pyramidal neuron dendrites modulate the summation of excitatory synaptic potentials4–6 and prevent the generation of dendritic calcium spikes7,8. Precisely timed somatic inhibition limits both the number of action potentials and the time window during which firing can occur8,9. The activity-dependent transcription factor NPAS4 regulates inhibitory syn...

  7. MYB transcription factor genes as regulators for plant responses: an overview

    OpenAIRE

    Ambawat, Supriya; Sharma, Poonam; Yadav, Neelam R.; Yadav, Ram C.

    2013-01-01

    Regulation of gene expression at the level of transcription controls many crucial biological processes. Transcription factors (TFs) play a great role in controlling cellular processes and MYB TF family is large and involved in controlling various processes like responses to biotic and abiotic stresses, development, differentiation, metabolism, defense etc. Here, we review MYB TFs with particular emphasis on their role in controlling different biological processes. This will provide valuable i...

  8. Intracellular Storage and Regulated Secretion of Von Willebrand Factor in Quantitative Von Willebrand Disease*

    OpenAIRE

    Wang, Jiong-Wei; Valentijn, Karine M.; de Boer, Hetty C.; Dirven, Richard J.; van Zonneveld, Anton Jan; Koster, Abraham J.; Voorberg, Jan; Reitsma, Pieter H.; Eikenboom, Jeroen

    2011-01-01

    Several missense mutations in the von Willebrand Factor (VWF) gene of von Willebrand disease (VWD) patients have been shown to cause impaired constitutive secretion and intracellular retention of VWF. However, the effects of those mutations on the intracellular storage in Weibel-Palade bodies (WPBs) of endothelial cells and regulated secretion of VWF remain unknown. We demonstrate, by expression of quantitative VWF mutants in HEK293 cells, that four missense mutations in the D3 and CK-domain ...

  9. Ciliary neurotrophic factor has intrinsic and extrinsic roles in regulating B cell differentiation and bone structure.

    OpenAIRE

    Maria Askmyr; White, Kirby E; Tanja Jovic; King, Hannah A.; Quach, Julie M.; Maluenda, Ana C.; Baker, Emma K; Smeets, Monique F.; Walkley, Carl R.; Purton, Louise E.

    2015-01-01

    The gp130 receptor and its binding partners play a central role in cytokine signalling. Ciliary neurotrophic factor (CNTF) is one of the cytokines that signals through the gp130 receptor complex. CNTF has previously been shown to be a negative regulator of trabecular bone remodelling and important for motor neuron development. Since haematopoietic cell maintenance and differentiation is dependent on the bone marrow (BM) microenvironment, where cells of the osteoblastic lineage are important r...

  10. RNA-destabilizing Factor Tristetraprolin Negatively Regulates NF-κB Signaling*

    OpenAIRE

    Liang, Jian; Lei, Tianhua; Song, Yuting; Yanes, Natalie; Qi, Yongfen; Fu, Mingui

    2009-01-01

    Tristetraprolin (TTP) is a CCCH zinc finger-containing protein that destabilizes mRNA by binding to an AU-rich element. Mice deficient in TTP develop a severe inflammatory syndrome mainly because of overproduction of tumor necrosis factor α. We report here that TTP also negatively regulates NF-κB signaling at the transcriptional corepressor level, by which it may repress inflammatory gene transcription. TTP expression inhibited NF-κB-dependent transcription. However, overexpression of TTP did...

  11. Regulation of Cerebral Cortical Size And Neuron Number by Fibroblast Growth Factors: Implications For Autism

    OpenAIRE

    Vaccarino, Flora M.; GRIGORENKO, Elena L.; Smith, Karen M.; Stevens, Hanna

    2008-01-01

    Increased brain size is common in children with autism spectrum disorders. Here we propose that an increased number of cortical excitatory neurons may underlie the increased brain volume, minicolumn pathology and excessive network excitability, leading to sensory hyper-reactivity and seizures, which are often found in autism. We suggest that Fibroblast Growth Factors (FGF), a family of genes that regulate cortical size and connectivity, may be responsible for these developmental alterations. ...

  12. Regulation of adiponectin production by insulin: interactions with tumor necrosis factor-α and interleukin-6

    OpenAIRE

    Hajri, Tahar; Tao, Huan; Wattacheril, Julia; Marks-Shulman, Pamela; Abumrad, Naji N.

    2010-01-01

    Obesity is often associated with insulin resistance, low-grade systemic inflammation, and reduced plasma adiponectin. Inflammation is also increased in adipose tissue, but it is not clear whether the reductions of adiponectin levels are related to dysregulation of insulin activity and/or increased proinflammatory mediators. In this study, we investigated the interactions of insulin, tumor necrosis factor-α (TNF-α) and interleukin 6 (IL-6) in the regulation of adiponectin production using in v...

  13. Vascular endothelial growth factor regulates angiogenesis and vascular permeability in Kaposi's sarcoma.

    OpenAIRE

    Cornali, E.; Zietz, C; Benelli, R; Weninger, W.; Masiello, L.; Breier, G; Tschachler, E; Albini, A; Stürzl, M

    1996-01-01

    Abundant vasculature with increased permeability is a prominent histological feature of Kaposi's sarcoma (KS), a multifocal, cytokine-regulated tumor. Here we report on the role of vascular endothelial growth factor (VEGF) in AIDS-KS angiogenesis and vascular permeability. We demonstrate that different cytokines, which were previously shown to be active in KS development, modulate VEGF expression in KS spindle cells and cooperate with VEGF on the functional level. Northern blot analysis as we...

  14. Nuclear Factor I isoforms regulate gene expression during the differentiation of human neural progenitors to astrocytes

    OpenAIRE

    Wilczynska, Katarzyna M.; Singh, Sandeep K.; Adams, Bret; Bryan, Lauren; Rao, Raj R.; Valerie, Kristoffer; Wright, Sarah; Griswold-Prenner, Irene; Kordula, Tomasz

    2009-01-01

    Even though astrocytes are critical for both normal brain functions and the development and progression of neuropathological states, including neuroinflammation associated with neurodegenerative diseases, the mechanisms controlling gene expression during astrocyte differentiation are poorly understood. Thus far, several signaling pathways were shown to regulate astrocyte differentiation, including JAK-STAT, BMP-2/Smads, and Notch. More recently, a family of Nuclear Factor-1 (NFI-A, -B, -C, an...

  15. Vascular Endothelial Growth Factor Receptor-3 Directly Interacts with Phosphatidylinositol 3-Kinase to Regulate Lymphangiogenesis

    OpenAIRE

    Coso, Sanja; Zeng, Yiping; Opeskin, Kenneth; Elizabeth D Williams

    2012-01-01

    Background Dysfunctional lymphatic vessel formation has been implicated in a number of pathological conditions including cancer metastasis, lymphedema, and impaired wound healing. The vascular endothelial growth factor (VEGF) family is a major regulator of lymphatic endothelial cell (LEC) function and lymphangiogenesis. Indeed, dissemination of malignant cells into the regional lymph nodes, a common occurrence in many cancers, is stimulated by VEGF family members. This effect is generally con...

  16. Endogenous Brain Derived Neurotrophic Factor in the Nucleus Tractus Solitarius Tonically Regulates Synaptic and Autonomic Function

    OpenAIRE

    Clark, Catharine G.; Hasser, Eileen M.; Kunze, Diana L.; Katz, David M.; Kline, David D.

    2011-01-01

    Brain derived neurotrophic factor (BDNF) and its receptor, TrkB, are highly expressed in the nucleus tractus solitarius (nTS), the principal target of cardiovascular primary afferent input to the brainstem. However, little is known about the role of BDNF signaling in nTS in cardiovascular homeostasis. We examined whether BDNF in nTS modulates cardiovascular function in vivo and regulates synaptic and/or neuronal activity in isolated brainstem slices. Microinjection of BDNF into the rat medial...

  17. Fibroblast Growth Factor Receptor Signaling in Oligodendrocytes Regulates Myelin Sheath Thickness

    OpenAIRE

    Furusho, M.; Dupree, J. L.; Nave, K-A; Bansal, R.

    2012-01-01

    Formation of the central nervous system (CNS) white matter is developmentally tightly regulated, but the molecules and mechanisms of myelination control in the postnatal CNS are poorly understood. Here, we show that myelin growth is controlled by Fibroblast Growth Factor (FGF) signaling, originally identified as a proliferative signal for oligodendrocyte precursor cells (OPC) in vitro. We created two lines of mice lacking both FGF-receptor 1 (Fgfr1) and Fgfr2 in oligodendrocyte lineage cells ...

  18. The Adipocyte-Expressed Forkhead Transcription Factor Foxc2 Regulates Metabolism Through Altered Mitochondrial Function

    OpenAIRE

    Lidell, Martin E.; Seifert, Erin L.; Westergren, Rickard; Heglind, Mikael; Gowing, Adrienne; Sukonina, Valentina; Arani, Zahra; Itkonen, Paula; Wallin, Simonetta; Westberg, Fredrik; Fernandez-Rodriguez, Julia; Laakso, Markku; Nilsson, Tommy; Peng, Xiao-Rong; Harper, Mary-Ellen

    2011-01-01

    OBJECTIVE Previous findings demonstrate that enhanced expression of the forkhead transcription factor Foxc2 in adipose tissue leads to a lean and insulin-sensitive phenotype. These findings prompted us to further investigate the role of Foxc2 in the regulation of genes of fundamental importance for metabolism and mitochondrial function. RESEARCH DESIGN AND METHODS The effects of Foxc2 on expression of genes involved in mitochondriogenesis and mitochondrial function were assessed by quantitati...

  19. Exploring membrane-associated NAC transcription factors in Arabidopsis: implications for membrane biology in genome regulation

    OpenAIRE

    Kim, Sun-Young; Kim, Sang-Gyu; Kim, Youn-Sung; Seo, Pil Joon; Bae, Mikyoung; Yoon, Hye-Kyung; Park, Chung-Mo

    2006-01-01

    Controlled proteolytic cleavage of membrane-associated transcription factors (MTFs) is an intriguing activation strategy that ensures rapid transcriptional responses to incoming stimuli. Several MTFs are known to regulate diverse cellular functions in prokaryotes, yeast, and animals. In Arabidopsis, a few NAC MTFs mediate either cytokinin signaling during cell division or endoplasmic reticulum (ER) stress responses. Through genome-wide analysis, it was found that at least 13 members of the NA...

  20. Key factors regulating the mass delivery of macromolecules to model cell membranes

    DEFF Research Database (Denmark)

    Campbell, Richard A.; Watkins, Erik B.; Jagalski, Vivien;

    2014-01-01

    We show that both gravity and electrostatics are key factors regulating interactions between model cell membranes and self-assembled liquid crystalline aggregates of dendrimers and phospholipids. The system is a proxy for the trafficking of reservoirs of therapeutic drugs to cell membranes for slow...... the aggregates to activate endocytosis pathways on specific cell types is discussed in the context of targeted drug delivery applications. © 2014 American Chemical Society....

  1. Regulation of Splicing Factors by Alternative Splicing and NMD Is Conserved between Kingdoms Yet Evolutionarily Flexible

    OpenAIRE

    Liana F Lareau; Brenner, Steven E.

    2015-01-01

    Ultraconserved elements, unusually long regions of perfect sequence identity, are found in genes encoding numerous RNA-binding proteins including arginine-serine rich (SR) splicing factors. Expression of these genes is regulated via alternative splicing of the ultraconserved regions to yield mRNAs that are degraded by nonsense-mediated mRNA decay (NMD), a process termed unproductive splicing (Lareau et al. 2007; Ni et al. 2007). As all human SR genes are affected by alternative splicing and N...

  2. Transcription Factors Foxi3 and Sox2 in the Regulation of Tooth Development

    OpenAIRE

    Jussila, Maria

    2014-01-01

    Teeth are ectodermal organs, which form from the embryonic epithelium and mesenchyme. Reciprocal interactions between these two tissues, regulated by the conserved signaling pathways, guide tooth morphogenesis. Activity of each signaling pathway is mediated by transcription factors, which activate or repress target genes of the pathway. During morphogenesis, the shape of the dental epithelium undergoes dramatic changes as it proceeds though placode, bud, and cap stages, finally forming the sh...

  3. Discrimination between thermodynamic models of cis-regulation using transcription factor occupancy data.

    Science.gov (United States)

    Zeigler, Robert D; Cohen, Barak A

    2014-02-01

    Many studies have identified binding preferences for transcription factors (TFs), but few have yielded predictive models of how combinations of transcription factor binding sites generate specific levels of gene expression. Synthetic promoters have emerged as powerful tools for generating quantitative data to parameterize models of combinatorial cis-regulation. We sought to improve the accuracy of such models by quantifying the occupancy of TFs on synthetic promoters in vivo and incorporating these data into statistical thermodynamic models of cis-regulation. Using chromatin immunoprecipitation-seq, we measured the occupancy of Gcn4 and Cbf1 in synthetic promoter libraries composed of binding sites for Gcn4, Cbf1, Met31/Met32 and Nrg1. We measured the occupancy of these two TFs and the expression levels of all promoters in two growth conditions. Models parameterized using only expression data predicted expression but failed to identify several interactions between TFs. In contrast, models parameterized with occupancy and expression data predicted expression data, and also revealed Gcn4 self-cooperativity and a negative interaction between Gcn4 and Nrg1. Occupancy data also allowed us to distinguish between competing regulatory mechanisms for the factor Gcn4. Our framework for combining occupancy and expression data produces predictive models that better reflect the mechanisms underlying combinatorial cis-regulation of gene expression. PMID:24288374

  4. 茶园土壤细菌丰度及其影响因子研究%Bacterial Abundance of Tea Garden Soils and Its Influencing Factors

    Institute of Scientific and Technical Information of China (English)

    韩文炎; 王皖蒙; 郭赟; 杨明臻; 贾仲君

    2013-01-01

    Bacterial abundances in tea garden and their adjacent forest and vegetable soils were investigated by real-time quantitative PCR (qPCR) as well as the factors that may affect the population size of bacterial communities. Soil DNA was extracted by using Griffiths’ method and bacterial abundance was determined by quantifying the copy number of 16S rRNA genes. The results showed that the bacterial abundance of tea garden soils ranged from 0.01×108 to 20.32×108 16 S rRNA gene copies/g (gram dry weight soil) with an average of 3.70×108 16 S rRNA gene copies/g, being similar with that in the forest soil, but far below that in the vegetable soil. The bacterial abundance in the tea garden soils was significantly and positively correlated with the soil pH and microbial biomass C (P<0.001) respectively, but significantly and negatively correlated with N application rate and age of tea plantation (P<0.01) respectively. There was no significant correlation between bacterial abundance and total organic C and total N in soil. Multiple regression analysis further indicated that bacterial abundance was affected most significantly by soil pH, followed by age of tea stand and annual N application rate. The results of this study suggested that soil amelioration such as raising soil pH and reducing the high rates of nitrogen application could be of great help for maintaining bacterial abundance and microbial diversity in tea garden soils.%  采用 Griffiths 法直接提取土壤微生物基因组 DNA,并通过实时荧光定量 PCR 技术分析土壤微生物16 S rRNA 基因数量,对茶园及其附近森林和菜园土壤的细菌丰度及其影响因素进行了研究。结果表明,茶园土壤细菌丰度在0.01×108~20.32×10816 S rRNA 基因拷贝数/g 之间,平均为3.70×10816 S rRNA 基因拷贝数/g,与酸性森林土壤大致相当,但明显低于中性菜园土壤。土壤细菌丰度与 pH 和微生物量 C 呈极显著正相关(P<0.001

  5. MicroRNA-24 Regulates Osteogenic Differentiation via Targeting T-Cell Factor-1

    Directory of Open Access Journals (Sweden)

    Weigong Zhao

    2015-05-01

    Full Text Available MicroRNAs (miRNAs have been reported to have diverse biological roles in regulating many biological processes, including osteogenic differentiation. In the present study, we identified that miR-24 was a critical regulator during osteogenic differentiation. We found that overexpression of miR-24 significantly inhibited osteogenic differentiation, which decreased alkaline phosphatase activity, matrix mineralization and the expression of osteogenic differentiation markers. In contrast, inhibition of miR-24 exhibited an opposite effect. Furthermore, we delineated that miR-24 regulates post-transcriptionals of T-cell factor-1 (Tcf-1 via targeting the 3'-untranslated region (UTR of Tcf-1 mRNA. MiR-24 was further found to regulate the protein expression of Tcf-1 in the murine osteoprogenitors cells and bone mesenchymal stem cells. Additionally, the positive effect of miR-24 suppression on osteoblast differentiation was apparently abrogated by Tcf-1 silencing. Taken together, our data suggest that miR-24 participates in osteogenic differentiation by targeting and regulating Tcf-1 expression in osteoblastic cells.

  6. Regulation of Nox enzymes expression in vascular pathophysiology: Focusing on transcription factors and epigenetic mechanisms

    Directory of Open Access Journals (Sweden)

    Simona-Adriana Manea

    2015-08-01

    Full Text Available NADPH oxidases (Nox represent a family of hetero-oligomeric enzymes whose exclusive biological function is the generation of reactive oxygen species (ROS. Nox-derived ROS are essential modulators of signal transduction pathways that control key physiological activities such as cell growth, proliferation, migration, differentiation, and apoptosis, immune responses, and biochemical pathways. Enhanced formation of Nox-derived ROS, which is generally associated with the up-regulation of different Nox subtypes, has been established in various pathologies, namely cardiovascular diseases, diabetes, obesity, cancer, and neurodegeneration. The detrimental effects of Nox-derived ROS are related to alterations in cell signalling and/or direct irreversible oxidative damage of nucleic acids, proteins, carbohydrates, and lipids. Thus, understanding of transcriptional regulation mechanisms of Nox enzymes have been extensively investigated in an attempt to find ways to counteract the excessive formation of Nox-derived ROS in various pathological states. Despite the numerous existing data, the molecular pathways responsible for Nox up-regulation are not completely understood. This review article summarizes some of the recent advances and concepts related to the regulation of Nox expression in the vascular pathophysiology. It highlights the role of transcription factors and epigenetic mechanisms in this process. Identification of the signalling molecules involved in Nox up-regulation, which is associated with the onset and development of cardiovascular dysfunction may contribute to the development of novel strategies for the treatment of cardiovascular diseases.

  7. Protein-Protein Interactions in the Regulation of WRKY Transcription Factors

    Institute of Scientific and Technical Information of China (English)

    Yingjun Chi; Yan Yang; Yuan Zhou; Jie Zhou; Baofang Fan; Jing-Quan Yu; Zhixiang Chen

    2013-01-01

    It has been almost 20 years since the first report of a WRKY transcription factor,SPF1,from sweet potato.Great progress has been made since then in establishing the diverse biological roles of WRKY transcription factors in plant growth,development,and responses to biotic and abiotic stress.Despite the functional diversity,almost all analyzed WRKY proteins recognize the TrGACC/T W-box sequences and,therefore,mechanisms other than mere recognition of the core W-box promoter elements are necessary to achieve the regulatory specificity of WRKY transcription factors.Research over the past several years has revealed that WRKY transcription factors physically interact with a wide range of proteins with roles in signaling,transcription,and chromatin remodeling.Studies of WRKY-interacting proteins have provided important insights into the regulation and mode of action of members of the important family of transcription factors.It has also emerged that the slightly varied WRKY domains and other protein motifs conserved within each of the seven WRKY subfamilies participate in protein-protein interactions and mediate complex functional interactions between WRKY proteins and between WRKY and other regulatory proteins in the modulation of important biological processes.In this review,we summarize studies of protein-protein interactions for WRKY transcription factors and discuss how the interacting partners contribute,at different levels,to the establishment of the complex regulatory and functional network of WRKY transcription factors.

  8. Daughter-specific transcription factors regulate cell size control in budding yeast.

    Directory of Open Access Journals (Sweden)

    Stefano Di Talia

    2009-10-01

    Full Text Available In budding yeast, asymmetric cell division yields a larger mother and a smaller daughter cell, which transcribe different genes due to the daughter-specific transcription factors Ace2 and Ash1. Cell size control at the Start checkpoint has long been considered to be a main regulator of the length of the G1 phase of the cell cycle, resulting in longer G1 in the smaller daughter cells. Our recent data confirmed this concept using quantitative time-lapse microscopy. However, it has been proposed that daughter-specific, Ace2-dependent repression of expression of the G1 cyclin CLN3 had a dominant role in delaying daughters in G1. We wanted to reconcile these two divergent perspectives on the origin of long daughter G1 times. We quantified size control using single-cell time-lapse imaging of fluorescently labeled budding yeast, in the presence or absence of the daughter-specific transcriptional regulators Ace2 and Ash1. Ace2 and Ash1 are not required for efficient size control, but they shift the domain of efficient size control to larger cell size, thus increasing cell size requirement for Start in daughters. Microarray and chromatin immunoprecipitation experiments show that Ace2 and Ash1 are direct transcriptional regulators of the G1 cyclin gene CLN3. Quantification of cell size control in cells expressing titrated levels of Cln3 from ectopic promoters, and from cells with mutated Ace2 and Ash1 sites in the CLN3 promoter, showed that regulation of CLN3 expression by Ace2 and Ash1 can account for the differential regulation of Start in response to cell size in mothers and daughters. We show how daughter-specific transcriptional programs can interact with intrinsic cell size control to differentially regulate Start in mother and daughter cells. This work demonstrates mechanistically how asymmetric localization of cell fate determinants results in cell-type-specific regulation of the cell cycle.

  9. The Survival and Recovery of Irradiated Bacterial Spores as Affected by Population Density and Some External Factors

    International Nuclear Information System (INIS)

    The radiation resistance of Bacillus cereus spores as affected by the pH-value and cell density of the irradiated spore suspensions was investigated. The portions of the survival curves of suspensions of 108, 4 x 103 and 5 x 101 per millilitre viable cell counts, respectively, were compared for a three-orders-of-magnitude decrease in viable cell count. It was established that the initial cell density did not affect radiation resistance of spores. Radiation resistance as affected by pH-value in the range of 3 to 8 was investigated. In the range of pH 5 to 8, the radiation resistance of B. cereus spores was not affected. By lowering the pH-value to below 5, the radiation resistance decreased below that observed in the neutral region. The colony-forming capacity of B. cereus, B. coagulans and B. pumilus as a function of the pH-value in the nutrient medium, and the pH-sensitivity of bacterial spores as affected by radiation, were also investigated. It was established that irradiation increased the pH-sensitivity of surviving bacterial spores in all three strains. The initial phase of spore germination (the phase accompanied by decrease of refractivity of the spores) and the division stage of vegetative cells proved to be the most sensitive to the value of the hydrogen ion concentration. (author)

  10. Stability of the rhizosphere and endophytic bacterial communities associated with Arabidopsis thaliana (L.) Heynh under impact of cosmic factors

    Science.gov (United States)

    Kordium, V. A.; Adamchuk-Chala, N. I.; Moshinec, H. V.

    The orbital experiment will involve a growing of Arabidopsis plant seed to seed in the presence of a plant probiotic bacteria consortium introduced into the system The purpose of experiment is to characterize microbial community associated with Arabidopsis thaliana and determine how consortium of introduced bacteria along with the endemic plant-associated bacteria influences the plant development reproductive system and seed formation in spaceflight conditions The first study will be an examination of the survival of model bacteria in on the inoculated plant The second complex study is to examine the plant traits in particular the ultrastructure of root statocytes in order to determine whether the plant development proceeds normally under microgravity conditions on background of introduced bacteria and to assess the structural changes occurring in the cotyledons generative organs and seeds The third set of observations will concern studies of the structure of microbial community associated with Arabidopsis plants with traditional and molecular tools The fourth part of the work will be an examination of mobile genetic elements that can play a role in adaptation of bacteria to the spaceflight conditions however they may affect the stability of bacterial endo- and rhizosphere communities The final part of the proposal initiates the study of possible risk of the bacterial consortium use for a plant inoculation in spaceflight conditions An evaluation of this risk will be performed via examination of expression of the Klebsiella

  11. Ubiquitination of the bacterial inositol phosphatase, SopB, regulates its biological activity at the plasma membrane.

    LENUS (Irish Health Repository)

    Knodler, Leigh A

    2009-11-01

    The Salmonella type III effector, SopB, is an inositol polyphosphate phosphatase that modulates host cell phospholipids at the plasma membrane and the nascent Salmonella-containing vacuole (SCV). Translocated SopB persists for many hours after infection and is ubiquitinated but the significance of this covalent modification has not been investigated. Here we identify by mass spectrometry six lysine residues of SopB that are mono-ubiquitinated. Substitution of these six lysine residues with arginine, SopB-K(6)R, almost completely eliminated SopB ubiquitination. We found that ubiquitination does not affect SopB stability or membrane association, or SopB-dependent events in SCV biogenesis. However, two spatially and temporally distinct events are dependent on ubiquitination, downregulation of SopB activity at the plasma membrane and prolonged retention of SopB on the SCV. Activation of the mammalian pro-survival kinase Akt\\/PKB, a downstream target of SopB, was intensified and prolonged after infection with the SopB-K(6)R mutant. At later times, fewer SCV were decorated with SopB-K(6)R compared with SopB. Instead SopB-K(6)R was present as discrete vesicles spread diffusely throughout the cell. Altogether, our data show that ubiquitination of SopB is not related to its intracellular stability but rather regulates its enzymatic activity at the plasma membrane and intracellular localization.

  12. Vimentin in Bacterial Infections.

    Science.gov (United States)

    Mak, Tim N; Brüggemann, Holger

    2016-01-01

    Despite well-studied bacterial strategies to target actin to subvert the host cell cytoskeleton, thus promoting bacterial survival, replication, and dissemination, relatively little is known about the bacterial interaction with other components of the host cell cytoskeleton, including intermediate filaments (IFs). IFs have not only roles in maintaining the structural integrity of the cell, but they are also involved in many cellular processes including cell adhesion, immune signaling, and autophagy, processes that are important in the context of bacterial infections. Here, we summarize the knowledge about the role of IFs in bacterial infections, focusing on the type III IF protein vimentin. Recent studies have revealed the involvement of vimentin in host cell defenses, acting as ligand for several pattern recognition receptors of the innate immune system. Two main aspects of bacteria-vimentin interactions are presented in this review: the role of vimentin in pathogen-binding on the cell surface and subsequent bacterial invasion and the interaction of cytosolic vimentin and intracellular pathogens with regards to innate immune signaling. Mechanistic insight is presented involving distinct bacterial virulence factors that target vimentin to subvert its function in order to change the host cell fate in the course of a bacterial infection. PMID:27096872

  13. Vimentin in Bacterial Infections

    Directory of Open Access Journals (Sweden)

    Tim N. Mak

    2016-04-01

    Full Text Available Despite well-studied bacterial strategies to target actin to subvert the host cell cytoskeleton, thus promoting bacterial survival, replication, and dissemination, relatively little is known about the bacterial interaction with other components of the host cell cytoskeleton, including intermediate filaments (IFs. IFs have not only roles in maintaining the structural integrity of the cell, but they are also involved in many cellular processes including cell adhesion, immune signaling, and autophagy, processes that are important in the context of bacterial infections. Here, we summarize the knowledge about the role of IFs in bacterial infections, focusing on the type III IF protein vimentin. Recent studies have revealed the involvement of vimentin in host cell defenses, acting as ligand for several pattern recognition receptors of the innate immune system. Two main aspects of bacteria-vimentin interactions are presented in this review: the role of vimentin in pathogen-binding on the cell surface and subsequent bacterial invasion and the interaction of cytosolic vimentin and intracellular pathogens with regards to innate immune signaling. Mechanistic insight is presented involving distinct bacterial virulence factors that target vimentin to subvert its function in order to change the host cell fate in the course of a bacterial infection.

  14. Periodic growth of bacterial colonies

    Science.gov (United States)

    Yamazaki, Yoshihiro; Ikeda, Takemasa; Shimada, Hirotoshi; Hiramatsu, Fumiko; Kobayashi, Naoki; Wakita, Jun-ichi; Itoh, Hiroto; Kurosu, Sayuri; Nakatsuchi, Michio; Matsuyama, Tohey; Matsushita, Mitsugu

    2005-06-01

    The formation of concentric ring colonies by bacterial species Bacillus subtilis and Proteus mirabilis has been investigated experimentally, focusing our attention on the dependence of local cell density upon the bacterial motility. It has been confirmed that these concentric ring colonies reflect the periodic change of the bacterial motility between motile cell state and immotile cell state. We conclude that this periodic change is macroscopically determined neither by biological factors (i.e., biological clock) nor by chemical factors (chemotaxis as inhibitor). And our experimental results strongly suggest that the essential factor for the change of the bacterial motility during concentric ring formation is the local cell density.

  15. The stress-regulated transcription factor CHOP promotes hepatic inflammatory gene expression, fibrosis, and oncogenesis.

    Directory of Open Access Journals (Sweden)

    Diane DeZwaan-McCabe

    Full Text Available Viral hepatitis, obesity, and alcoholism all represent major risk factors for hepatocellular carcinoma (HCC. Although these conditions also lead to integrated stress response (ISR or unfolded protein response (UPR activation, the extent to which these stress pathways influence the pathogenesis of HCC has not been tested. Here we provide multiple lines of evidence demonstrating that the ISR-regulated transcription factor CHOP promotes liver cancer. We show that CHOP expression is up-regulated in liver tumors in human HCC and two mouse models thereof. Chop-null mice are resistant to chemical hepatocarcinogenesis, and these mice exhibit attenuation of both apoptosis and cellular proliferation. Chop-null mice are also resistant to fibrosis, which is a key risk factor for HCC. Global gene expression profiling suggests that deletion of CHOP reduces the levels of basal inflammatory signaling in the liver. Our results are consistent with a model whereby CHOP contributes to hepatic carcinogenesis by promoting inflammation, fibrosis, cell death, and compensatory proliferation. They implicate CHOP as a common contributing factor in the development of HCC in a variety of chronic liver diseases.

  16. Human factor H-related protein 2 (CFHR2 regulates complement activation.

    Directory of Open Access Journals (Sweden)

    Hannes U Eberhardt

    Full Text Available Mutations and deletions within the human CFHR gene cluster on chromosome 1 are associated with diseases, such as dense deposit disease, CFHR nephropathy or age-related macular degeneration. Resulting mutant CFHR proteins can affect complement regulation. Here we identify human CFHR2 as a novel alternative pathway complement regulator that inhibits the C3 alternative pathway convertase and terminal pathway assembly. CFHR2 is composed of four short consensus repeat domains (SCRs. Two CFHR2 molecules form a dimer through their N-terminal SCRs, and each of the two C-terminal ends can bind C3b. C3b bound CFHR2 still allows C3 convertase formation but the CFHR2 bound convertases do not cleave the substrate C3. Interestingly CFHR2 hardly competes off factor H from C3b. Thus CFHR2 likely acts in concert with factor H, as CFHR2 inhibits convertases while simultaneously allowing factor H assisted degradation by factor I.

  17. An R2R3-MYB Transcription Factor Regulates Eugenol Production in Ripe Strawberry Fruit Receptacles.

    Science.gov (United States)

    Medina-Puche, Laura; Molina-Hidalgo, Francisco Javier; Boersma, Maaike; Schuurink, Robert C; López-Vidriero, Irene; Solano, Roberto; Franco-Zorrilla, José-Manuel; Caballero, José Luis; Blanco-Portales, Rosario; Muñoz-Blanco, Juan

    2015-06-01

    Eugenol is a volatile phenylpropanoid that contributes to flower and ripe fruit scent. In ripe strawberry (Fragaria × ananassa) fruit receptacles, eugenol is biosynthesized by eugenol synthase (FaEGS2). However, the transcriptional regulation of this process is still unknown. We have identified and functionally characterized an R2R3 MYB transcription factor (emission of benzenoid II [FaEOBII]) that seems to be the orthologous gene of PhEOBII from Petunia hybrida, which contributes to the regulation of eugenol biosynthesis in petals. The expression of FaEOBII was ripening related and fruit receptacle specific, although high expression values were also found in petals. This expression pattern of FaEOBII correlated with eugenol content in both fruit receptacle and petals. The expression of FaEOBII was repressed by auxins and activated by abscisic acid, in parallel to the ripening process. In ripe strawberry receptacles, where the expression of FaEOBII was silenced, the expression of cinnamyl alcohol dehydrogenase1 and FaEGS2, two structural genes involved in eugenol production, was down-regulated. A subsequent decrease in eugenol content in ripe receptacles was also observed, confirming the involvement of FaEOBII in eugenol metabolism. Additionally, the expression of FaEOBII was under the control of FaMYB10, another R2R3 MYB transcription factor that regulates the early and late biosynthetic genes from the flavonoid/phenylpropanoid pathway. In parallel, the amount of eugenol in FaMYB10-silenced receptacles was also diminished. Taken together, these data indicate that FaEOBII plays a regulating role in the volatile phenylpropanoid pathway gene expression that gives rise to eugenol production in ripe strawberry receptacles. PMID:25931522

  18. Regulations of essential amino acids and proteomics of bacterial endophytes Sphingomonas sp. Lk11 during cadmium uptake.

    Science.gov (United States)

    Khan, Abdul Latif; Ullah, Ihsan; Hussain, Javid; Kang, Sang-Mo; Al-Harrasi, Ahmed; Al-Rawahi, Ahmed; Lee, In-Jung

    2016-07-01

    Endophytic bacteria have been recently known for their potential to bioaccumulate metal from contaminated mediums. However, little is known about the physiological responses of phytohormone producing (gibberellins and auxins) endophytes during metal stressed environment. Endophytic bacteria Sphingomonas sp. LK11 was assessed for metals bioaccumulation and its physiological responses towards metal stress. The endophyte was grown in cadmium (Cd), zinc (Zn), aluminum (Al), manganese (Mn), and copper (Cu) contaminated mediums. The results revealed significantly higher endophytic growth potentials in Cd, Cu and Zn contaminations; however, the bio-accumulation rate of Cd was more prolific as compared to Zn and Cu. Interestingly, the SDS-PAGE profile showed increased expressions of proteins in Zn and Cu than in Cd. A similar attenuate response of amino acids was also observed for Cd than in case of Zn and Cu. Only asparagine, glutamate and proline showed significant impact in Cd while Cu and Zn had significantly higher responses of almost all amino acids. Detailed protein profile showed the activation of chaperone, antioxidative and detoxification proteins. Increased regulations of oxidoreductases, superoxide dismutase, thioredoxin, malate dehydrogenase, 2-oxoisovalerate dehydrogenase, 2-oxoisovalerate dehydrogenase, and dihydrolipoyl dehydrogenase were observed. The cellular defense-related protein responses were potent against Cd stress. The results conclude that Sphingomonas sp. LK11 reprogram its amino acids and proteomic expressions and maintain a steady growth during Cd stress. Using such phytohromones producing endophytic bacterium can be ideal approach to increase the phytoextraction potential of metal remediating plants. © 2014 Wiley Periodicals, Inc. Environ Toxicol 31: 887-896, 2016. PMID:25533023

  19. The homeobox transcription factor Even-skipped regulates acquisition of electrical properties in Drosophila neurons

    Directory of Open Access Journals (Sweden)

    Brand Andrea H

    2006-11-01

    Full Text Available Abstract Background While developmental processes such as axon pathfinding and synapse formation have been characterized in detail, comparatively less is known of the intrinsic developmental mechanisms that regulate transcription of ion channel genes in embryonic neurons. Early decisions, including motoneuron axon targeting, are orchestrated by a cohort of transcription factors that act together in a combinatorial manner. These transcription factors include Even-skipped (Eve, islet and Lim3. The perdurance of these factors in late embryonic neurons is, however, indicative that they might also regulate additional aspects of neuron development, including the acquisition of electrical properties. Results To test the hypothesis that a combinatorial code transcription factor is also able to influence the acquisition of electrical properties in embryonic neurons we utilized the molecular genetics of Drosophila to manipulate the expression of Eve in identified motoneurons. We show that increasing expression of this transcription factor, in two Eve-positive motoneurons (aCC and RP2, is indeed sufficient to affect the electrical properties of these neurons in early first instar larvae. Specifically, we observed a decrease in both the fast K+ conductance (IKfast and amplitude of quantal cholinergic synaptic input. We used charybdotoxin to pharmacologically separate the individual components of IKfast to show that increased Eve specifically down regulates the Slowpoke (a BK Ca2+-gated potassium channel, but not Shal, component of this current. Identification of target genes for Eve, using DNA adenine methyltransferase identification, revealed strong binding sites in slowpoke and nAcRα-96Aa (a nicotinic acetylcholine receptor subunit. Verification using real-time PCR shows that pan-neuronal expression of eve is sufficient to repress transcripts for both slo and nAcRα-96Aa. Conclusion Taken together, our findings demonstrate, for the first time, that Eve

  20. NF-κB Regulates B-Cell-Derived Nerve Growth Factor Expression

    Institute of Scientific and Technical Information of China (English)

    Klaus Heese; Noriko Inoue; Tohru Sawada

    2006-01-01

    In the mammalian brain, four neurotrophins have been identified: nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), neurotrophin-3 (NT-3) and neurotrophin-4/5 (NT-4/5). NGF exerts an important role in the development and functions of the central and peripheral nervous system. However, it has recently been documented that several types of immune cells, such as mast cells, lymphocytes, basophils and eosinophils, produce,store and release NGF. Accumulating preclinical and clinical data indicate that dysfunctions of NGF and the other neurotrophins may contribute to impaired immune responses and concentration of NGF frequently correlates with disease severity. Thus, the aim of this study was to elucidate the potential signaling mechanisms of cytokineneurotrophins interactions contributing to increased NGF levels. Our data show that the transcription factorNF-κB plays a pivotal role in regulating B-cell-derived NGF expression.

  1. Nuclear Factor-κB: Activation and Regulation during Toll-like Receptor Signaling

    Institute of Scientific and Technical Information of China (English)

    Ruaidhrí J. Carmody; Youhai H. Chen

    2007-01-01

    Toll-like receptors (TLRs) recognize distinct microbial components to initiate the innate and adaptive immune responses. TLR activation culminates in the expression of appropriate pro-inflammatory and immunomodulatory factors to meet pathogenic challenges. The transcription factor NF-κB is the master regulator of all TLR-induced responses and its activation is the pivotal event in TLR-mediated activation of the innate immune response. Many of the key molecular events required for TLR-induced NF-κB activation have been elucidated. However, much remain to be learned about the ability of TLRs to generate pathogen-specific responses using a limited number of transcription factors. This review will focus on our current understanding of NF-κB activation by TLRs and potential mechanisms for achieving a signal-specific response through NF-κB.

  2. Tandem machine learning for the identification of genes regulated by transcription factors

    Directory of Open Access Journals (Sweden)

    Schuetz Erin G

    2005-08-01

    Full Text Available Abstract Background The identification of promoter regions that are regulated by a given transcription factor has traditionally relied upon the identification and distributions of binding sites recognized by the factor. In this study, we have developed a tandem machine learning approach for the identification of regulatory target genes based on these parameters and on the corresponding binding site information contents that measure the affinities of the factor for these cognate elements. Results This method has been validated using models of DNA binding sites recognized by the xenobiotic-sensitive nuclear receptor, PXR/RXRα, for target genes within the human genome. An information theory-based weight matrix was first derived and refined from known PXR/RXRα binding sites. The promoter region of candidate genes was scanned with the weight matrix. A novel information density-based clustering algorithm was then used to identify clusters of information rich sites. Finally, transformed data representing metrics of location, strength and clustering of binding sites were used for classification of promoter regions using an ensemble approach involving neural networks, decision trees and Naïve Bayesian classification. The method was evaluated on a set of 24 known target genes and 288 genes known not to be regulated by PXR/RXRα. We report an average accuracy (proportion of correctly classified promoter regions of 71%, sensitivity of 73%, and specificity of 70%, based on multiple cross-validation and the leave-one-out strategy. The performance on a test set of 13 genes showed that 10 were correctly classified. Conclusion We have developed a machine learning approach for the successful detection of gene targets for transcription factors with high accuracy. The method has been validated for the transcription factor PXR/RXRα and has the potential to be extended to other transcription factors.

  3. Involvement of GATA transcription factors in the regulation of endogenous bovine interferon-tau gene transcription.

    Science.gov (United States)

    Bai, Hanako; Sakurai, Toshihiro; Kim, Min-Su; Muroi, Yoshikage; Ideta, Atsushi; Aoyagi, Yoshito; Nakajima, Hiromi; Takahashi, Masashi; Nagaoka, Kentaro; Imakawa, Kazuhiko

    2009-12-01

    Expression of interferon-tau (IFNT), necessary for pregnancy establishment in ruminant ungulates, is regulated in a temporal and spatial manner. However, molecular mechanisms by which IFNT gene transcription is regulated in this manner have not been firmly established. In this study, DNA microarray/RT-PCR analysis between bovine trophoblast CT-1 and Mardin-Darby bovine kidney (MDBK) cells was initially performed, finding that transcription factors GATA2, GATA3, and GATA6 mRNAs were specific to CT-1 cells. These mRNAs were also found in Days 17, 20, and 22 (Day 0 = day of estrus) bovine conceptuses. In examining other bovine cell lines, ovary cumulus granulosa (oCG) and ear fibroblast (EF) cells, GATA2 and GATA3, but not GATA6, were found specific to the bovine trophoblast cells. In transient transfection analyses using the upstream region (-631 to +59 bp) of bovine IFNT gene (bIFNT, IFN-tau-c1), over-expression of GATA2/GATA3 did not affect the transcription of bIFNT-reporter construct in human choriocarcinoma JEG3 cells. Transfection of GATA2, GATA3, ETS2, and/or CDX2, however, was effective in the up-regulation of the bIFNT construct transfected into bovine oCG and EF cells. One Point mutation studies revealed that among six potential GATA binding sites located on the upstream region of the bIFNT gene, the one next to ETS2 site exhibited reduced luciferase activity. In CT-1 cells, endogenous bIFNT gene transcription was up-regulated by over-expression of GATA2 or GATA3, but down-regulated by siRNA specific to GATA2 mRNA. These data suggest that GATA2/3 is involved in trophoblast-specific regulation of bIFNT gene transcription. PMID:19598245

  4. Negative transcriptional regulation of mitochondrial transcription factor A (TFAM) by nuclear TFAM

    International Nuclear Information System (INIS)

    Highlights: • TFAM localizes in nuclei and mitochondria of neuronal cells. • Nuclear TFAM does not bind the Tfam promoter. • Nuclear TFAM reduced the Tfam promoter activity via suppressing NRF-1 activity. • A novel self-negative feedback regulation of Tfam gene expression is explored. • FAM may play different roles depending on its subcellular localizations. - Abstract: The nuclear DNA-encoded mitochondrial transcription factor A (TFAM) is synthesized in cytoplasm and transported into mitochondria. TFAM enhances both transcription and replication of mitochondrial DNA. It is unclear, however, whether TFAM plays a role in regulating nuclear gene expression. Here, we demonstrated that TFAM was localized to the nucleus and mitochondria by immunostaining, subcellular fractionation, and TFAM-green fluorescent protein hybrid protein studies. In HT22 hippocampal neuronal cells, human TFAM (hTFAM) overexpression suppressed human Tfam promoter-mediated luciferase activity in a dose-dependent manner. The mitochondria targeting sequence-deficient hTFAM also repressed Tfam promoter activity to the same degree as hTFAM. It indicated that nuclear hTFAM suppressed Tfam expression without modulating mitochondrial activity. The repression required for nuclear respiratory factor-1 (NRF-1), but hTFAM did not bind to the NRF-1 binding site of its promoter. TFAM was co-immunoprecipitated with NRF-1. Taken together, we suggest that nuclear TFAM down-regulate its own gene expression as a NRF-1 repressor, showing that TFAM may play different roles depending on its subcellular localizations

  5. Negative transcriptional regulation of mitochondrial transcription factor A (TFAM) by nuclear TFAM

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Eun Jin; Kang, Young Cheol; Park, Wook-Ha; Jeong, Jae Hoon; Pak, Youngmi Kim, E-mail: ykpak@khu.ac.kr

    2014-07-18

    Highlights: • TFAM localizes in nuclei and mitochondria of neuronal cells. • Nuclear TFAM does not bind the Tfam promoter. • Nuclear TFAM reduced the Tfam promoter activity via suppressing NRF-1 activity. • A novel self-negative feedback regulation of Tfam gene expression is explored. • FAM may play different roles depending on its subcellular localizations. - Abstract: The nuclear DNA-encoded mitochondrial transcription factor A (TFAM) is synthesized in cytoplasm and transported into mitochondria. TFAM enhances both transcription and replication of mitochondrial DNA. It is unclear, however, whether TFAM plays a role in regulating nuclear gene expression. Here, we demonstrated that TFAM was localized to the nucleus and mitochondria by immunostaining, subcellular fractionation, and TFAM-green fluorescent protein hybrid protein studies. In HT22 hippocampal neuronal cells, human TFAM (hTFAM) overexpression suppressed human Tfam promoter-mediated luciferase activity in a dose-dependent manner. The mitochondria targeting sequence-deficient hTFAM also repressed Tfam promoter activity to the same degree as hTFAM. It indicated that nuclear hTFAM suppressed Tfam expression without modulating mitochondrial activity. The repression required for nuclear respiratory factor-1 (NRF-1), but hTFAM did not bind to the NRF-1 binding site of its promoter. TFAM was co-immunoprecipitated with NRF-1. Taken together, we suggest that nuclear TFAM down-regulate its own gene expression as a NRF-1 repressor, showing that TFAM may play different roles depending on its subcellular localizations.

  6. Myeloid-Derived Suppressor Cell Survival and Function Are Regulated by the Transcription Factor Nrf2.

    Science.gov (United States)

    Beury, Daniel W; Carter, Kayla A; Nelson, Cassandra; Sinha, Pratima; Hanson, Erica; Nyandjo, Maeva; Fitzgerald, Phillip J; Majeed, Amry; Wali, Neha; Ostrand-Rosenberg, Suzanne

    2016-04-15

    Tumor-induced myeloid-derived suppressor cells (MDSC) contribute to immune suppression in tumor-bearing individuals and are a major obstacle to effective immunotherapy. Reactive oxygen species (ROS) are one of the mechanisms used by MDSC to suppress T cell activation. Although ROS are toxic to most cells, MDSC survive despite their elevated content and release of ROS. NF erythroid 2-related factor 2 (Nrf2) is a transcription factor that regulates a battery of genes that attenuate oxidative stress. Therefore, we hypothesized that MDSC resistance to ROS may be regulated by Nrf2. To test this hypothesis, we used Nrf2(+/+)and Nrf2(-/-)BALB/c and C57BL/6 mice bearing 4T1 mammary carcinoma and MC38 colon carcinoma, respectively. Nrf2 enhanced MDSC suppressive activity by increasing MDSC production of H2O2, and it increased the quantity of tumor-infiltrating MDSC by reducing their oxidative stress and rate of apoptosis. Nrf2 did not affect circulating levels of MDSC in tumor-bearing mice because the decreased apoptotic rate of tumor-infiltrating MDSC was balanced by a decreased rate of differentiation from bone marrow progenitor cells. These results demonstrate that Nrf2 regulates the generation, survival, and suppressive potency of MDSC, and that a feedback homeostatic mechanism maintains a steady-state level of circulating MDSC in tumor-bearing individuals. PMID:26936880

  7. R2R3 MYB transcription factors: key regulators of the flavonoid biosynthetic pathway in grapevine.

    Science.gov (United States)

    Czemmel, Stefan; Heppel, Simon C; Bogs, Jochen

    2012-06-01

    Flavonoids compose one of the most abundant and important subgroups of secondary metabolites with more than 6,000 compounds detected so far in higher plants. They are found in various compositions and concentrations in nearly all plant tissues. Besides the attraction of pollinators and dispersers to fruits and flowers, flavonoids also protect against a plethora of stresses including pathogen attack, wounding and UV irradiation. Flavonoid content and composition of fruits such as grapes, bilberries, strawberries and apples as well as food extracts such as green tea, wine and chocolate have been associated with fruit quality including taste, colour and health-promoting effects. To unravel the beneficial potentials of flavonoids on fruit quality, research has been focused recently on the molecular basis of flavonoid biosynthesis and regulation in economically important fruit-producing plants such as grapevine (Vitis vinifera L.). Transcription factors and genes encoding biosynthetic enzymes have been characterized, studies that set a benchmark for future research on the regulatory networks controlling flavonoid biosynthesis and diversity. This review summarizes recent advances in the knowledge of regulatory cascades involved in flavonoid biosynthesis in grapevine. Transcriptional regulation of flavonoid biosynthesis during berry development is highlighted, with a particular focus on MYB transcription factors as molecular clocks, key regulators and powerful biotechnological tools to identify novel pathway enzymes to optimize flavonoid content and composition in grapes. PMID:22307206

  8. The role of emotion regulation in the relations between psychopathy factors and impulsive and premeditated aggression.

    Science.gov (United States)

    Long, Katherine; Felton, Julia W; Lilienfeld, Scott O; Lejuez, Carl W

    2014-10-01

    Given the high rates of aggressive behavior among highly psychopathic individuals, much research has sought to clarify the nature of the relation between psychopathy and aggression. The present study examined relations between Fearless Dominance (PPI FD), Self-Centered Impulsivity (PPI SCI), and Coldheartedness (PPI CH) Factors of the Psychopathic Personality Inventory (PPI; Lilienfeld & Andrews, 1996) and aggression dimensions (premeditated and impulsive aggression) in a sample of substance users receiving inpatient treatment. At the univariate level, PPI FD traits were significantly and positively related to premeditated aggression, but were not significantly related to impulsive aggression. PPI SCI traits were positively related to both forms of aggression, whereas PPI CH was not significantly related to either aggression dimension. Emotion regulation difficulties, as measured by the Difficulties with Emotion Regulation Scale (DERS; Gratz & Roemer, 2004), were negatively related to PPI FD traits, positively related to PPI SCI traits, and negatively related to PPI CH traits. Both PPI SCI and PPI FD traits exerted significant indirect effects on impulsive aggression through the DERS. In contrast, the DERS did not mediate the relations between psychopathic traits and premeditated aggression. Results provide a more nuanced understanding of the psychopathy-aggression relations and suggest that difficulties with emotion regulation may be an important mediator of the relations between psychopathy factors and impulsive aggression. PMID:25198433

  9. Jasmonate-Responsive ERF Transcription Factors Regulate Steroidal Glycoalkaloid Biosynthesis in Tomato.

    Science.gov (United States)

    Thagun, Chonprakun; Imanishi, Shunsuke; Kudo, Toru; Nakabayashi, Ryo; Ohyama, Kiyoshi; Mori, Tetsuya; Kawamoto, Koichi; Nakamura, Yukino; Katayama, Minami; Nonaka, Satoko; Matsukura, Chiaki; Yano, Kentaro; Ezura, Hiroshi; Saito, Kazuki; Hashimoto, Takashi; Shoji, Tsubasa

    2016-05-01

    Steroidal glycoalkaloids (SGAs) are cholesterol-derived specialized metabolites produced in species of the Solanaceae. Here, we report that a group of jasmonate-responsive transcription factors of the ETHYLENE RESPONSE FACTOR (ERF) family (JREs) are close homologs of alkaloid regulators in Cathranthus roseus and tobacco, and regulate production of SGAs in tomato. In transgenic tomato, overexpression and dominant suppression of JRE genes caused drastic changes in SGA accumulation and in the expression of genes for metabolic enzymes involved in the multistep pathway leading to SGA biosynthesis, including the upstream mevalonate pathway. Transactivation and DNA-protein binding assays demonstrate that JRE4 activates the transcription of SGA biosynthetic genes by binding to GCC box-like elements in their promoters. These JRE-binding elements occur at significantly higher frequencies in proximal promoter regions of the genes regulated by JRE genes, supporting the conclusion that JREs mediate transcriptional co-ordination of a series of metabolic genes involved in SGA biosynthesis. PMID:27084593

  10. Ciliary neurotrophic factor has intrinsic and extrinsic roles in regulating B cell differentiation and bone structure.

    Science.gov (United States)

    Askmyr, Maria; White, Kirby E; Jovic, Tanja; King, Hannah A; Quach, Julie M; Maluenda, Ana C; Baker, Emma K; Smeets, Monique F; Walkley, Carl R; Purton, Louise E

    2015-01-01

    The gp130 receptor and its binding partners play a central role in cytokine signalling. Ciliary neurotrophic factor (CNTF) is one of the cytokines that signals through the gp130 receptor complex. CNTF has previously been shown to be a negative regulator of trabecular bone remodelling and important for motor neuron development. Since haematopoietic cell maintenance and differentiation is dependent on the bone marrow (BM) microenvironment, where cells of the osteoblastic lineage are important regulators, we hypothesised that CNTF may also have important roles in regulating haematopoiesis. Analysis of haematopoietic parameters in male and female Cntf(-/-) mice at 12 and 24 weeks of age revealed altered B lymphopoiesis. Strikingly, the B lymphocyte phenotype differed based on sex, age and also the BM microenvironment in which the B cells develop. When BM cells from wildtype mice were transplanted into Cntf(-/-) mice, there were minimal effects on B lymphopoiesis or bone parameters. However, when Cntf(-/-) BM cells were transplanted into a wildtype BM microenvironment, there were changes in both haematopoiesis and bone parameters. Our data reveal that haematopoietic cell-derived CNTF has roles in regulating BM B cell lymphopoiesis and both trabecular and cortical bone, the latter in a sex-dependent manner. PMID:26487326

  11. The E2F-DP1 Transcription Factor Complex Regulates Centriole Duplication in Caenorhabditis elegans.

    Science.gov (United States)

    Miller, Jacqueline G; Liu, Yan; Williams, Christopher W; Smith, Harold E; O'Connell, Kevin F

    2016-01-01

    Centrioles play critical roles in the organization of microtubule-based structures, from the mitotic spindle to cilia and flagella. In order to properly execute their various functions, centrioles are subjected to stringent copy number control. Central to this control mechanism is a precise duplication event that takes place during S phase of the cell cycle and involves the assembly of a single daughter centriole in association with each mother centriole . Recent studies have revealed that posttranslational control of the master regulator Plk4/ZYG-1 kinase and its downstream effector SAS-6 is key to ensuring production of a single daughter centriole. In contrast, relatively little is known about how centriole duplication is regulated at a transcriptional level. Here we show that the transcription factor complex EFL-1-DPL-1 both positively and negatively controls centriole duplication in the Caenorhabditis elegans embryo. Specifically, we find that down regulation of EFL-1-DPL-1 can restore centriole duplication in a zyg-1 hypomorphic mutant and that suppression of the zyg-1 mutant phenotype is accompanied by an increase in SAS-6 protein levels. Further, we find evidence that EFL-1-DPL-1 promotes the transcription of zyg-1 and other centriole duplication genes. Our results provide evidence that in a single tissue type, EFL-1-DPL-1 sets the balance between positive and negative regulators of centriole assembly and thus may be part of a homeostatic mechanism that governs centriole assembly. PMID:26772748

  12. The E2F-DP1 Transcription Factor Complex Regulates Centriole Duplication in Caenorhabditis elegans

    Directory of Open Access Journals (Sweden)

    Jacqueline G. Miller

    2016-03-01

    Full Text Available Centrioles play critical roles in the organization of microtubule-based structures, from the mitotic spindle to cilia and flagella. In order to properly execute their various functions, centrioles are subjected to stringent copy number control. Central to this control mechanism is a precise duplication event that takes place during S phase of the cell cycle and involves the assembly of a single daughter centriole in association with each mother centriole . Recent studies have revealed that posttranslational control of the master regulator Plk4/ZYG-1 kinase and its downstream effector SAS-6 is key to ensuring production of a single daughter centriole. In contrast, relatively little is known about how centriole duplication is regulated at a transcriptional level. Here we show that the transcription factor complex EFL-1-DPL-1 both positively and negatively controls centriole duplication in the Caenorhabditis elegans embryo. Specifically, we find that down regulation of EFL-1-DPL-1 can restore centriole duplication in a zyg-1 hypomorphic mutant and that suppression of the zyg-1 mutant phenotype is accompanied by an increase in SAS-6 protein levels. Further, we find evidence that EFL-1-DPL-1 promotes the transcription of zyg-1 and other centriole duplication genes. Our results provide evidence that in a single tissue type, EFL-1-DPL-1 sets the balance between positive and negative regulators of centriole assembly and thus may be part of a homeostatic mechanism that governs centriole assembly.

  13. Extracellular Matrix-Regulated Gene Expression RequiresCooperation of SWI/SNF and Transcription Factors

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Ren; Spencer, Virginia A.; Bissell, Mina J.

    2006-05-25

    Extracellular cues play crucial roles in the transcriptional regulation of tissue-specific genes, but whether and how these signals lead to chromatin remodeling is not understood and subject to debate. Using chromatin immunoprecipitation (ChIP) assays and mammary-specific genes as models, we show here that extracellular matrix (ECM) molecules and prolactin cooperate to induce histone acetylation and binding of transcription factors and the SWI/SNF complex to the {beta}- and ?-casein promoters. Introduction of a dominant negative Brg1, an ATPase subunit of SWI/SNF complex, significantly reduced both {beta}- and ?-casein expression, suggesting that SWI/SNF-dependent chromatin remodeling is required for transcription of mammary-specific genes. ChIP analyses demonstrated that the ATPase activity of SWI/SNF is necessary for recruitment of RNA transcriptional machinery, but not for binding of transcription factors or for histone acetylation. Coimmunoprecipitation analyses showed that the SWI/SNF complex is associated with STAT5, C/EBP{beta}, and glucocorticoid receptor (GR). Thus, ECM- and prolactin-regulated transcription of the mammary-specific casein genes requires the concerted action of chromatin remodeling enzymes and transcription factors.

  14. [Regulation of neurogenesis: factors affecting of new neurons formation in adult mammals brain].

    Science.gov (United States)

    Respondek, Michalina; Buszman, Ewa

    2015-01-01

    Neurogenesis is a complex and multi-step process of generating completely functional neurons. This process in adult brain is based on pluripotentional neuronal stem cells (NSC), which are able to proliferation and differentiation into mature neurons or glial cells. NSC are located in subgranular zone inside hippocampus and in subventricular zone. The new neurons formation depends on many endo- and exogenous factors which modulate each step of neurogenesis. This article describes the most important regulators of adult neurogenesis, mainly: neurotrophins, growth factors, hormones, neurotransmitters and microenvironment of NSC. Some drugs, especially antipsychotics, antidepressants and normothymics may affect the neurogenic properties of adult brain. Moreover pathological processes such as neuroinflammation, stroke or epilepsy are able to induce proliferation of NSC. The proneurogenic effects of psychotropic drugs and pathological processes are associated with their ability to increase some hormones and neurotrophins level, as well as with rising the expression of antiapoptotic Bcl-2 protein and metalloproteinase MMP-2. Additionaly, some drugs, for example haloperidol, are able to block prolactin and dopaminergic neuroblasts receptors. Down-regulation of adult neurogenesis is associated with alcohol abuse and high stress level. Negative effect of many drugs, such as cytostatics, COX-2 inhibitors and opioides was also observed. The proneurogenic effect of described factors suggest their broad therapeutic potential and gives a new perspective on an effective and modern treatment of many neuropsychiatric disorders. This effect can also help to clarify the pathogenesis of disorders associated with proliferation and degeneration of adult brain cells. PMID:27259217

  15. ADP-Ribosylation Factor 1 Regulates Proliferation, Migration, and Fusion in Early Stage of Osteoclast Differentiation

    Directory of Open Access Journals (Sweden)

    Min Jae Kim

    2015-12-01

    Full Text Available Small G-protein adenosine diphosphate (ADP-ribosylation factors (ARFs regulate a variety of cellular functions, including actin cytoskeleton remodeling, plasma membrane reorganization, and vesicular transport. Here, we propose the functional roles of ARF1 in multiple stages of osteoclast differentiation. ARF1 was upregulated during receptor activator of nuclear factor kappa-B ligand (RANKL-induced osteoclast differentiation and transiently activated in an initial stage of their differentiation. Differentiation of ARF1-deficient osteoclast precursors into mature osteoclasts temporarily increased in pre-maturation stage of osteoclasts followed by reduced formation of mature osteoclasts, indicating that ARF1 regulates the osteoclastogenic process. ARF1 deficiency resulted in reduced osteoclast precursor proliferation and migration as well as increasing cell-cell fusion. In addition, ARF1 silencing downregulated c-Jun N-terminal kinase (JNK, Akt, osteopontin, and macrophage colony-stimulating factor (M-CSF-receptor c-Fms as well as upregulating several fusion-related genes including CD44, CD47, E-cadherin, and meltrin-α. Collectively, we showed that ARF1 stimulated proliferation and migration of osteoclast precursors while suppressing their fusion, suggesting that ARF1 may be a plausible inter-player that mediates the transition to osteoclast fusion at multiple steps during osteoclast differentiation

  16. Activity-dependent brain-derived neurotrophic factor expression regulates cortistatin-interneurons and sleep behavior

    Directory of Open Access Journals (Sweden)

    Martinowich Keri

    2011-03-01

    Full Text Available Abstract Background Sleep homeostasis is characterized by a positive correlation between sleep length and intensity with the duration of the prior waking period. A causal role for brain-derived neurotrophic factor (BDNF in sleep homeostasis has been suggested, but the underlying mechanisms remain unclear. Cortistatin, a neuropeptide expressed primarily in a subset of cortical GABAergic interneurons, is another molecule implicated in sleep homeostasis. Results We confirmed that sleep deprivation leads to an increase in cortical cortistatin mRNA expression. Disruption of activity-dependent BDNF expression in a genetically modified mouse line impairs both baseline levels of cortistatin mRNA as well as its levels following sleep deprivation. Disruption of activity-dependent BDNF also leads to a decrease in sleep time during the active (dark phase. Conclusion Our studies suggest that regulation of cortistatin-expressing interneurons by activity-dependent BDNF expression may contribute to regulation of sleep behavior.

  17. Nuclear Factor Erythroid-2 Like 1 (NFE2L1): Structure, function and regulation.

    Science.gov (United States)

    Kim, Hyun Min; Han, Jeong Woo; Chan, Jefferson Y

    2016-06-10

    Nrf1 (also referred to as NFE2L1) is a member of the CNC-bZIP family of transcription factors that are characterized by a highly conserved CNC-domain, and a basic-leucine zipper domain required for dimerization and DNA binding. Nrf1 is ubiquitously expressed across tissue and cell types as various isoforms, and is induced by stress signals from a broad spectrum of stimuli. Evidence indicates that Nrf1 plays an important role in regulating a range of cellular functions including oxidative stress response, differentiation, inflammatory response, metabolism, and maintaining proteostasis. Thus, Nrf1 has been implicated in the pathogenesis of various disease processes including cancer development, and degenerative and metabolic disorders. This review summarizes our current understanding of Nrf1 and the molecular mechanism underlying its regulation and action in different cellular functions. PMID:26947393

  18. [Transforming growth factor beta-1: structure, function, and regulation mechanisms in cancer].

    Science.gov (United States)

    Peralta-Zaragoza, O; Lagunas-Martínez, A; Madrid-Marina, V

    2001-01-01

    Transforming growth factor beta-1 (TGF-beta 1) is produced by several cell lineages such as lymphocytes, macrophages, and dendritic cells, and its expression serves in both autocrine and paracrine modes to control the differentiation, proliferation, and state of activation of these and other cells. In general, TGF-beta 1 has pleiotropic properties on the immune response during the development of infection diseases and cancer; however, the mechanisms of action and regulation of gene expression of this cytokine are poorly understood, in this review, the biological properties and the molecular mechanisms that regulate TGF-beta 1 gene expression are described, to understand the role of this cytokine in growth and cell differentiation. The knowledge of molecular mechanisms of gene expression of TGF-beta 1 may serve to develop new cancer therapies. The English version of this paper is available at: http://www.insp.mx/salud/index.html PMID:11547595

  19. [Shifts in metabolism and its regulation under the effect of spaceflight factors].

    Science.gov (United States)

    Larina, I M; Nichiporuk, I A; Veselova, O M; Vasilieva, G Yu; Popova, I A

    2013-01-01

    The review deals with the results of studying the adaptive changes in metabolism and its neuroendocrine regulation in humans and animals under the effect of spaceflight factors and ground-based simulation of the gravitational unloading. The majority of the investigations were concerned with the water-electrolyte and mineral turnover, as well as protein, lipid and carbohydrates metabolism. Biochemical measurements of the body liquids (blood, urine and saliva) before, in and after space flight or in ground simulation experiments were used as indictors of the status of sympathoadrenal, hypothalamo-pituitary-adrenal and other systems involved in systemic regulation of metabolism, and also strength of stress-reaction to adversities. The authors generalized data on the interrelation and interaction of the neuroendocrine and psychophysiological status both in the real and simulated conditions of space flight. PMID:23700613

  20. Ligand-specific sequential regulation of transcription factors for differentiation of MCF-7 cells

    Directory of Open Access Journals (Sweden)

    Toyoda Tetsuro

    2009-11-01

    Full Text Available Abstract Background Sharing a common ErbB/HER receptor signaling pathway, heregulin (HRG induces differentiation of MCF-7 human breast cancer cells while epidermal growth factor (EGF elicits proliferation. Although cell fates resulting from action of the aforementioned ligands completely different, the respective gene expression profiles in early transcription are qualitatively similar, suggesting that gene expression during late transcription, but not early transcription, may reflect ligand specificity. In this study, based on both the data from time-course quantitative real-time PCR on over 2,000 human transcription factors and microarray of all human genes, we identified a series of transcription factors which may control HRG-specific late transcription in MCF-7 cells. Results We predicted that four transcription factors including EGR4, FRA-1, FHL2, and DIPA should have responsibility of regulation in MCF-7 cell differentiation. Validation analysis suggested that one member of the activator protein 1 (AP-1 family, FOSL-1 (FRA-1 gene, appeared immediately following c-FOS expression, might be responsible for expression of transcription factor FHL2 through activation of the AP-1 complex. Furthermore, RNAi gene silencing of FOSL-1 and FHL2 resulted in increase of extracellular signal-regulated kinase (ERK phosphorylation of which duration was sustained by HRG stimulation. Conclusion Our analysis indicated that a time-dependent transcriptional regulatory network including c-FOS, FRA-1, and FHL2 is vital in controlling the ERK signaling pathway through a negative feedback loop for MCF-7 cell differentiation.

  1. The bacterial cell cycle regulator GcrA is a σ70 cofactor that drives gene expression from a subset of methylated promoters.

    Science.gov (United States)

    Haakonsen, Diane L; Yuan, Andy H; Laub, Michael T

    2015-11-01

    Cell cycle progression in most organisms requires tightly regulated programs of gene expression. The transcription factors involved typically stimulate gene expression by binding specific DNA sequences in promoters and recruiting RNA polymerase. Here, we found that the essential cell cycle regulator GcrA in Caulobacter crescentus activates the transcription of target genes in a fundamentally different manner. GcrA forms a stable complex with RNA polymerase and localizes to almost all active σ(70)-dependent promoters in vivo but activates transcription primarily at promoters harboring certain DNA methylation sites. Whereas most transcription factors that contact σ(70) interact with domain 4, GcrA interfaces with domain 2, the region that binds the -10 element during strand separation. Using kinetic analyses and a reconstituted in vitro transcription assay, we demonstrated that GcrA can stabilize RNA polymerase binding and directly stimulate open complex formation to activate transcription. Guided by these studies, we identified a regulon of ∼ 200 genes, providing new insight into the essential functions of GcrA. Collectively, our work reveals a new mechanism for transcriptional regulation, and we discuss the potential benefits of activating transcription by promoting RNA polymerase isomerization rather than recruitment exclusively. PMID:26545812

  2. Nerve Growth Factor Is Regulated by Toll-Like Receptor 2 in Human Intervertebral Discs.

    Science.gov (United States)

    Krock, Emerson; Currie, J Brooke; Weber, Michael H; Ouellet, Jean A; Stone, Laura S; Rosenzweig, Derek H; Haglund, Lisbet

    2016-02-12

    Nerve growth factor (NGF) contributes to the development of chronic pain associated with degenerative connective tissue pathologies, such as intervertebral disc degeneration and osteoarthritis. However, surprisingly little is known about the regulation of NGF in these conditions. Toll-like receptors (TLR) are pattern recognition receptors classically associated with innate immunity but more recently were found to be activated by endogenous alarmins such as fragmented extracellular matrix proteins found in degenerating discs or cartilage. In this study we investigated if TLR activation regulates NGF and which signaling mechanisms control this response in intervertebral discs. TLR2 agonists, TLR4 agonists, or IL-1β (control) treatment increased NGF, brain-derived neurotrophic factor (BDNF), and IL-1β gene expression in human disc cells isolated from healthy, pain-free organ donors. However, only TLR2 activation or IL-1β treatment increased NGF protein secretion. TLR2 activation increased p38, ERK1/2, and p65 activity and increased p65 translocation to the cell nucleus. JNK activity was not affected by TLR2 activation. Inhibition of NF-κB, and to a lesser extent p38, but not ERK1/2 activity, blocked TLR2-driven NGF up-regulation at both the transcript and protein levels. These results provide a novel mechanism of NGF regulation in the intervertebral disc and potentially other pathogenic connective tissues. TLR2 and NF-κB signaling are known to increase cytokines and proteases, which accelerate matrix degradation. Therefore, TLR2 or NF-κB inhibition may both attenuate chronic pain and slow the degenerative progress in vivo. PMID:26668319

  3. Regulation of coagulation factor XI expression by microRNAs in the human liver.

    Directory of Open Access Journals (Sweden)

    Salam Salloum-Asfar

    Full Text Available High levels of factor XI (FXI increase the risk of thromboembolic disease. However, the genetic and environmental factors regulating FXI expression are still largely unknown. The aim of our study was to evaluate the regulation of FXI by microRNAs (miRNAs in the human liver. In silico prediction yielded four miRNA candidates that might regulate FXI expression. HepG2 cells were transfected with miR-181a-5p, miR-23a-3p, miR-16-5p and miR-195-5p. We used mir-494, which was not predicted to bind to F11, as a negative control. Only miR-181a-5p caused a significant decrease both in FXI protein and F11 mRNA levels. In addition, transfection with a miR-181a-5p inhibitor in PLC/PRF/5 hepatic cells increased both the levels of F11 mRNA and extracellular FXI. Luciferase assays in human colon cancer cells deficient for Dicer (HCT-DK demonstrated a direct interaction between miR-181a-5p and 3'untranslated region of F11. Additionally, F11 mRNA levels were inversely and significantly correlated with miR-181a-5p levels in 114 healthy livers, but not with miR-494. This study demonstrates that FXI expression is directly regulated by a specific miRNA, miR-181a-5p, in the human liver. Future studies are necessary to further investigate the potential consequences of miRNA dysregulation in pathologies involving FXI.

  4. Regulation of neuroendocrine cells and neuron factors in the ovary by zinc oxide nanoparticles.

    Science.gov (United States)

    Liu, Xin-Qi; Zhang, Hong-Fu; Zhang, Wei-Dong; Zhang, Peng-Fei; Hao, Ya-Nan; Song, Ran; Li, Lan; Feng, Yan-Ni; Hao, Zhi-Hui; Shen, Wei; Min, Ling-Jiang; Yang, Hong-Di; Zhao, Yong

    2016-08-10

    The pubertal period is an important window during the development of the female reproductive system. Development of the pubertal ovary, which supplies the oocytes intended for fertilization, requires growth factors, hormones, and neuronal factors. It has been reported that zinc oxide nanoparticles (ZnO NPs) cause cytotoxicity of neuron cells. However, there have been no reports of the effects of ZnO NPs on neuronal factors and neuroendocrine cells in the ovary (in vivo). For the first time, this in vivo study investigated the effects of ZnO NPs on gene and protein expression of neuronal factors and the population of neuroendocrine cells in ovaries. Intact NPs were detected in ovarian tissue and although ZnO NPs did not alter body weight, they reduced the ovary organ index. Compared to the control or ZnSO4 treatments, ZnO NPs treatments differentially regulated neuronal factor protein and gene expression, and the population of neuroendocrine cells. ZnO NPs changed the contents of essential elements in the ovary; however, they did not alter levels of the steroid hormones estrogen and progesterone. These data together suggest that intact ZnO NPs might pose a toxic effect on neuron development in the ovary and eventually negatively affect ovarian developmental at puberty. PMID:27215404

  5. Mechanically stimulated bone cells secrete paracrine factors that regulate osteoprogenitor recruitment, proliferation, and differentiation.

    Science.gov (United States)

    Brady, Robert T; O'Brien, Fergal J; Hoey, David A

    2015-03-27

    Bone formation requires the recruitment, proliferation and osteogenic differentiation of mesenchymal progenitors. A potent stimulus driving this process is mechanical loading, yet the signalling mechanisms underpinning this are incompletely understood. The objective of this study was to investigate the role of the mechanically-stimulated osteocyte and osteoblast secretome in coordinating progenitor contributions to bone formation. Initially osteocytes (MLO-Y4) and osteoblasts (MC3T3) were mechanically stimulated for 24 hrs and secreted factors within the conditioned media were collected and used to evaluate mesenchymal stem cell (MSC) and osteoblast recruitment, proliferation and osteogenesis. Paracrine factors secreted by mechanically stimulated osteocytes significantly enhanced MSC migration, proliferation and osteogenesis and furthermore significantly increased osteoblast migration and proliferation when compared to factors secreted by statically cultured osteocytes. Secondly, paracrine factors secreted by mechanically stimulated osteoblasts significantly enhanced MSC migration but surprisingly, in contrast to the osteocyte secretome, inhibited MSC proliferation when compared to factors secreted by statically cultured osteoblasts. A similar trend was observed in osteoblasts. This study provides new information on mechanically driven signalling mechanisms in bone and highlights a contrasting secretome between cells at different stages in the bone lineage, furthering our understanding of loading-induced bone formation and indirect biophysical regulation of osteoprogenitors. PMID:25721667

  6. Aspirin inhibits Chlamydia pneumoniae : Induced nuclear factor-kappa B activation, cytokine expression, and bacterial development in human endothelial cells

    NARCIS (Netherlands)

    Tiran, A; Gruber, HJ; Graier, WF; Wagner, AH; van Leeuwen, EBM; Tiran, B

    2002-01-01

    Objective-Chlamydia pneumoniae has been associated with atherosclerosis. Infection of vascular endothelial cells with C pneumoniae increases the expression of proatherogenic cytokines mediated by nuclear factor (NF)-kappaB, a transcription factor. The present study was designed to test the effect of

  7. An NAC transcription factor controls ethylene-regulated cell expansion in flower petals.

    Science.gov (United States)

    Pei, Haixia; Ma, Nan; Tian, Ji; Luo, Jing; Chen, Jiwei; Li, Jing; Zheng, Yi; Chen, Xiang; Fei, Zhangjun; Gao, Junping

    2013-10-01

    Cell expansion is crucial for plant growth. It is well known that the phytohormone ethylene functions in plant development as a key modulator of cell expansion. However, the role of ethylene in the regulation of this process remains unclear. In this study, 2,189 ethylene-responsive transcripts were identified in rose (Rosa hybrida) petals using transcriptome sequencing and microarray analysis. Among these transcripts, an NAC (for no apical meristem [NAM], Arabidopsis transcription activation factor [ATAF], and cup-shaped cotyledon [CUC])-domain transcription factor gene, RhNAC100, was rapidly and dramatically induced by ethylene in the petals. Interestingly, accumulation of the RhNAC100 transcript was modulated by ethylene via microRNA164-dependent posttranscriptional regulation. Overexpression of RhNAC100 in Arabidopsis (Arabidopsis thaliana) substantially reduced the petal size by repressing petal cell expansion. By contrast, silencing of RhNAC100 in rose petals using virus-induced gene silencing significantly increased petal size and promoted cell expansion in the petal abaxial subepidermis (P genes tested exhibited changes in expression in RhNAC100-silenced rose petals. Moreover, of those genes, one cellulose synthase and two aquaporin genes (Rosa hybrida Cellulose Synthase2 and R. hybrida Plasma Membrane Intrinsic Protein1;1/2;1) were identified as targets of RhNAC100. Our results suggest that ethylene regulates cell expansion by fine-tuning the microRNA164/RhNAC100 module and also provide new insights into the function of NAC transcription factors. PMID:23933991

  8. Advanced Glycation End-Products affect transcription factors regulating insulin gene expression

    International Nuclear Information System (INIS)

    Advanced Glycation End-Products (AGEs) are generated by the covalent interaction of reducing sugars with proteins, lipids or nucleic acids. AGEs are implicated in diabetic complications and pancreatic β-cell dysfunction. We previously demonstrated that exposure of the pancreatic islet cell line HIT-T15 to high concentrations of AGEs leads to a significant decrease of insulin secretion and content. Insulin gene transcription is positively regulated by the beta cell specific transcription factor PDX-1 (Pancreatic and Duodenal Homeobox-1). On the contrary, the forkhead transcription factor FoxO1 inhibits PDX-1 gene transcription. Activity of FoxO1 is regulated by post-translational modifications: phosphorylation deactivates FoxO1, and acetylation prevents FoxO1 ubiquitination. In this work we investigated whether AGEs affect expression and subcellular localization of PDX-1 and FoxO1. HIT-T15 cells were cultured for 5 days in presence of AGEs. Cells were then lysed and processed for subcellular fractionation. We determined intracellular insulin content, then we assessed the expression and subcellular localization of PDX-1, FoxO1, phosphoFoxO1 and acetylFoxO1. As expected intracellular insulin content was lower in HIT-T15 cells cultured with AGEs. The results showed that AGEs decreased expression and nuclear localization of PDX-1, reduced phosphorylation of FoxO1, and increased expression and acetylation of FoxO1. These results suggest that AGEs decrease insulin content unbalancing transcription factors regulating insulin gene expression.

  9. Identification of trans-acting factors regulating SamDC expression in Oryza sativa

    Energy Technology Data Exchange (ETDEWEB)

    Basu, Supratim, E-mail: supratim_genetics@yahoo.co.in [Department of Crop Soil and Environmental Sciences, University of Arkansas, Fayetteville, AR 72701 (United States); Division of Plant Biology, Bose Institute, Kolkata (India); Roychoudhury, Aryadeep [Post Graduate Department of Biotechnology, St. Xavier' s College (Autonomous), 30, Mother Teresa Sarani, Kolkata - 700016, West Bengal (India); Sengupta, Dibyendu N. [Division of Plant Biology, Bose Institute, Kolkata (India)

    2014-03-07

    Highlights: • Identification of cis elements responsible for SamDC expression by in silico analysis. • qPCR analysis of SamDC expression to abiotic and biotic stress treatments. • Detection of SamDC regulators using identified cis-elements as probe by EMSA. • Southwestern Blot analysis to predict the size of the trans-acting factors. - Abstract: Abiotic stress affects the growth and productivity of crop plants; to cope with the adverse environmental conditions, plants have developed efficient defense machinery comprising of antioxidants like phenolics and flavonoids, and osmolytes like polyamines. SamDC is a key enzyme in the polyamine biosynthesis pathway in plants. In our present communication we have done in silico analysis of the promoter region of SamDC to look for the presence of different cis-regulatory elements contributing to its expression. Based on the presence of different cis-regulatory elements we completed comparative analysis of SamDC gene expression in rice lamina of IR-29 and Nonabokra by qPCR in response to the abiotic stress treatments of salinity, drought, cold and the biotic stress treatments of ABA and light. Additionally, to explore the role of the cis-regulatory elements in regulating the expression of SamDC gene in plants we comparatively analyzed the binding of rice nuclear proteins prepared from IR-29 and Nonabokra undergoing various stress treatments. The intensity of the complex formed was low and inducible in IR-29 in contrast to Nonabokra. Southwestern blot analysis helped in predicting the size of the trans-acting factors binding to these cis-elements. To our knowledge this is the first report on the comprehensive analysis of SamDC gene expression in rice and identification of the trans-acting factors regulating its expression.

  10. VeA and LaeA transcriptional factors regulate ochratoxin A biosynthesis in Aspergillus carbonarius.

    Science.gov (United States)

    Crespo-Sempere, A; Marín, S; Sanchis, V; Ramos, A J

    2013-09-16

    Ochratoxin A (OTA) is a mycotoxin with nephrotoxic, teratogenic and immunotoxic properties which represents a serious risk for human and animal health. Aspergillus carbonarius is considered the main OTA-producing species in grapes and products such as raisins, wine or juices, although it has also been isolated from coffee, cocoa and cereals. Till now not much information is available about regulatory mechanisms of OTA production by A. carbonarius. A better understanding of how environmental factors influence OTA production and which genes are involved in its regulation could help us design new control strategies. In this study, we have evaluated the role of VeA and LaeA transcriptional factors, which have been shown to regulate secondary metabolism in response to light in A. carbonarius. To this aim, veA and laeA genes were deleted in an ochratoxigenic A. carbonarius strain by targeted gene replacement using Agrobacterium tumefaciens-mediated transformation. Loss of veA and laeA in A. carbonarius yields to an organism with slight differences in vegetative growth but a strong reduction in conidial production. A drastic decrease of OTA production that ranged from 68.5 to 99.4% in ΔveA and ΔlaeA null mutants was also observed, which was correlated with a downregulation of a nonribosomal peptide synthetase involved in OTA biosynthesis. These findings suggest that VeA and LaeA have an important role regulating conidiation and OTA biosynthesis in response to light in A. carbonarius in a similar way to other fungi where functions of VeA and LaeA have been previously described. This is the first report of a transcriptional factor governing the production of OTA by A. carbonarius. PMID:24041999

  11. A new role for plant R2R3-MYB transcription factors in cell cycle regulation

    Institute of Scientific and Technical Information of China (English)

    Eleonora Cominelli; Chiara Tonelli

    2009-01-01

    @@ MYB proteins are transcription factors present in all eukaryotes,sharing a common DNA-binding domain that consists of one to three imperfect helix-helix-turn-helix repeats of about 50 amino acids,called RI,R2,and R3 respectively [1].In animals and yeast these proteins represent a small gene family [1].Animal R1R2R3-MYB proteins have been described for their role in cell cycle regulation mainly at the G1/S,but also at the G2/M transition,as firstly demonstrated in Drosophila [2].

  12. Transcription factors involved in the regulation of natural killer cell development and function: an update

    Directory of Open Access Journals (Sweden)

    Martha Elia Luevano

    2012-10-01

    Full Text Available Natural Killer (NK cells belong to the innate immune system and are key effectors in the immune response against cancer and infection. Recent studies have contributed to the knowledge of events controlling NK cell fate. The use of knockout mice has enabled the discovery of key transcription factors (TFs essential for NK cell development and function. Yet, unwrapping the downstream targets of these TFs and their influence on NK cells remains a challenge. In this review we discuss the latest TFs described to be involved in the regulation of NK cell development and maturation.

  13. Hypoxia-inducible factors - regulation, role and comparative aspects in tumourigenesis

    DEFF Research Database (Denmark)

    Hansen, A E; Kristensen, A T; Law, I;

    2011-01-01

    Hypoxia-inducible factors (HIFs) play a key role in the cellular response experienced in hypoxic tumours, mediating adaptive responses that allow hypoxic cells to survive in the hostile environment. Identification and understanding of tumour hypoxia and the influence on cellular processes carries...... important prognostic information and may help identify potential hypoxia circumventing and targeting strategies. This review summarizes current knowledge on HIF regulation and function in tumour cells and discusses the aspects of using companion animals as comparative spontaneous cancer models. Spontaneous...... tumours in companion animals hold a great research potential for the evaluation and understanding of tumour hypoxia and in the development of hypoxia-targeting therapeutics....

  14. ATAF1 transcription factor directly regulates abscisic acid biosynthetic gene NCED3 in Arabidopsis thaliana

    DEFF Research Database (Denmark)

    Jensen, Michael Krogh; Lindemose, Søren; De Masi, Federico;

    2013-01-01

    ATAF1, an Arabidopsis thaliana NAC transcription factor, plays important roles in plant adaptation to environmental stress and development. To search for ATAF1 target genes, we used protein binding microarrays and chromatin-immunoprecipitation (ChIP). This identified T[A,C,G]CGT[A,G] and TT...... key abscisic acid (ABA) phytohormone biosynthetic gene NCED3. ChIP-qPCR and expression analysis showed that ATAF1 binding to the NCED3 promoter correlated with increased NCED3 expression and ABA hormone levels. These results indicate that ATAF1 regulates ABA biosynthesis....

  15. Identification and characterization of seed-specific transcription factors regulating anthocyanin biosynthesis in black rice

    OpenAIRE

    Kim, C.-K; Cho, M.-A.; Choi, Y.-H.; Kim, J.-A.; Kim, Y.-H.; Kim, Y.-K.; Park, S.-H

    2011-01-01

    Black rice is rich in anthocyanin and is expected to have more healthful dietary potential than white rice. We assessed expression of anthocyanin in black rice cultivars using a newly designed 135 K Oryza sativa microarray. A total of 12,673 genes exhibited greater than 2.0-fold up- or down-regulation in comparisons between three rice cultivars and three seed developmental stages. The 137 transcription factor genes found to be associated with production of anthocyanin pigment were classified ...

  16. Engineering the Oryza sativa cell wall with rice NAC transcription factors regulating secondary wall formation

    Directory of Open Access Journals (Sweden)

    Kouki eYoshida

    2013-10-01

    Full Text Available Plant tissues that require structural rigidity synthesize a thick, strong secondary cell wall of lignin, cellulose and hemicelluloses in a complicated bridged structure. Master regulators of secondary wall synthesis were identified in dicots, and orthologs of these regulators have been identified in monocots, but regulation of secondary cell wall formation in monocots has not been extensively studied. Here we demonstrate that the rice transcription factors SECONDARY WALL NAC DOMAIN PROTEINs (SWNs can regulate secondary wall formation in rice (Oryza sativa and are potentially useful for engineering the monocot cell wall. The OsSWN1 promoter is highly active in sclerenchymatous cells of the leaf blade and less active in xylem cells. By contrast, the OsSWN2 promoter is highly active in xylem cells and less active in sclerenchymatous cells. OsSWN2 splicing variants encode two proteins; the shorter protein (OsSWN2S has very low transcriptional activation ability, but the longer protein (OsSWN2L and OsSWN1 have strong transcriptional activation ability. In rice, expression of an OsSWN2S chimeric repressor, driven by the OsSWN2 promoter, resulted in stunted growth and para-wilting (leaf rolling and browning under normal water conditions due to impaired vascular vessels. The same OsSWN2S chimeric repressor, driven by the OsSWN1 promoter, caused a reduction of cell wall thickening in sclerenchymatous cells, a drooping leaf phenotype, reduced lignin and xylose contents and increased digestibility as forage. These data suggest that OsSWNs regulate secondary wall formation in rice and manipulation of OsSWNs may enable improvements in monocotyledonous crops for forage or biofuel applications.

  17. Engineering the Oryza sativa cell wall with rice NAC transcription factors regulating secondary wall formation.

    Science.gov (United States)

    Yoshida, Kouki; Sakamoto, Shingo; Kawai, Tetsushi; Kobayashi, Yoshinori; Sato, Kazuhito; Ichinose, Yasunori; Yaoi, Katsuro; Akiyoshi-Endo, Miho; Sato, Hiroko; Takamizo, Tadashi; Ohme-Takagi, Masaru; Mitsuda, Nobutaka

    2013-01-01

    Plant tissues that require structural rigidity synthesize a thick, strong secondary cell wall of lignin, cellulose and hemicelluloses in a complicated bridged structure. Master regulators of secondary wall synthesis were identified in dicots, and orthologs of these regulators have been identified in monocots, but regulation of secondary cell wall formation in monocots has not been extensively studied. Here we demonstrate that the rice transcription factors SECONDARY WALL NAC DOMAIN PROTEINs (SWNs) can regulate secondary wall formation in rice (Oryza sativa) and are potentially useful for engineering the monocot cell wall. The OsSWN1 promoter is highly active in sclerenchymatous cells of the leaf blade and less active in xylem cells. By contrast, the OsSWN2 promoter is highly active in xylem cells and less active in sclerenchymatous cells. OsSWN2 splicing variants encode two proteins; the shorter protein (OsSWN2S) has very low transcriptional activation ability, but the longer protein (OsSWN2L) and OsSWN1 have strong transcriptional activation ability. In rice, expression of an OsSWN2S chimeric repressor, driven by the OsSWN2 promoter, resulted in stunted growth and para-wilting (leaf rolling and browning under normal water conditions) due to impaired vascular vessels. The same OsSWN2S chimeric repressor, driven by the OsSWN1 promoter, caused a reduction of cell wall thickening in sclerenchymatous cells, a drooping leaf phenotype, reduced lignin and xylose contents and increased digestibility as forage. These data suggest that OsSWNs regulate secondary wall formation in rice and manipulation of OsSWNs may enable improvements in monocotyledonous crops for forage or biofuel applications. PMID:24098302

  18. Strong negative self regulation of Prokaryotic transcription factors increases the intrinsic noise of protein expression

    Directory of Open Access Journals (Sweden)

    Jenkins Dafyd J

    2008-01-01

    Full Text Available Abstract Background Many prokaryotic transcription factors repress their own transcription. It is often asserted that such regulation enables a cell to homeostatically maintain protein abundance. We explore the role of negative self regulation of transcription in regulating the variability of protein abundance using a variety of stochastic modeling techniques. Results We undertake a novel analysis of a classic model for negative self regulation. We demonstrate that, with standard approximations, protein variance relative to its mean should be independent of repressor strength in a physiological range. Consequently, in that range, the coefficient of variation would increase with repressor strength. However, stochastic computer simulations demonstrate that there is a greater increase in noise associated with strong repressors than predicted by theory. The discrepancies between the mathematical analysis and computer simulations arise because with strong repressors the approximation that leads to Michaelis-Menten-like hyperbolic repression terms ceases to be valid. Because we observe that strong negative feedback increases variability and so is unlikely to be a mechanism for noise control, we suggest instead that negative feedback is evolutionarily favoured because it allows the cell to minimize mRNA usage. To test this, we used in silico evolution to demonstrate that while negative feedback can achieve only a modest improvement in protein noise reduction compared with the unregulated system, it can achieve good improvement in protein response times and very substantial improvement in reducing mRNA levels. Conclusion Strong negative self regulation of transcription may not always be a mechanism for homeostatic control of protein abundance, but instead might be evolutionarily favoured as a mechanism to limit the use of mRNA. The use of hyperbolic terms derived from quasi-steady-state approximation should also be avoided in the analysis of stochastic

  19. Regulacin de la mineralizacin sea por factores inorgnicos y peptdicos Regulation of Bone Mineralization by inorganic and peptide factors

    Directory of Open Access Journals (Sweden)

    A.L Negri

    2011-10-01

    osteoctico perilacunar.Orthotopic mineralization begins with the production of matrix vesicles that are produced by polarized budding of the surface of condrocytes, osteoblasts and odontoblasts. It occurs in two steps: The first one is the formation of hydroxiapatite crystals within the matrix vesicles, followed by the propagation of the hydroxiapatite crystals through the membrane vesicle into the extra cellular matrix. In the regulation of orthotopic mineralization, apart from tissue-specific cells, a great number of enzymes, inorganic and peptide factors participate, that have complex interactions among them. Inorganic pyrophosphate (PPi antagonizes the ability of phosphate (Pi to crystallize with calcium and to form hydroxiapatite, thus suppressing its propagation. For the normal mineralization to continue, an adjusted balance of the extra cellular Pi and PPi levels is needed. Three molecules have been identified that have a central role in the regulation of extra cellular PPi levels: tissue non-specific alkaline phosphatase (TNAP, which hydrolyzes PPi, the nucleotide pyrophosphatase phosphodiesterase 1 (NPP1, which generates PPi from triphosphate nucleosides, and the multiple-steps transmembrane protein ANK which transfers PPi from the intracellular to the extracellular compartment. There are, in turn, two SIBLING proteins called DMP1 and MEPE that regulate mineralization. The expression of DMP1 by the osteocyte is dramatically induced in response to mechanical loading increasing bone mineralization. MEPE protein contains a protease resistant motif called ASARM, which is believed to be the candidate for the mineralization inhibitor (minhibin. Osteopontin is another mineralization inhibitor in its phosphorilated form and its secretion is markedly reduced in knockout mice for NPP1. Present data seem to support the hypothesis that these molecules could be the translators of bone strain and participate in the regulation of mineralization of the perilacunar osteocytic space.

  20. Voltage-Sensitive Load Controllers for Voltage Regulation and Increased Load Factor in Distribution Systems

    DEFF Research Database (Denmark)

    Douglass, Philip James; Garcia-Valle, Rodrigo; Østergaard, Jacob;

    2014-01-01

    -voltage distribution systems with residential loads including voltage-sensitive water heaters. In low-voltage systems, the results of the simulations show the controller to be effective at reducing the extremes of voltage and increasing the load factor while respecting end-use temperature constraints. In medium......This paper presents a novel controller design for controlling appliances based on local measurements of voltage. The controller finds the normalized voltage deviation accounting for the sensitivity of voltage measurements to appliance state. The controller produces a signal indicating desired power...... consumption which can be mapped to temperature setpoint offsets of thermostat controlled loads. In networks where a lower voltage level corresponds to high system load (and vice versa), this controller acts to regulate voltage and increase the load factor. Simulations are conducted on low- and medium...

  1. Regulation of Epidermal Growth Factor Receptor Trafficking by Lysine Deacetylase HDAC6

    DEFF Research Database (Denmark)

    Lissanu Deribe, Yonathan; Wild, Philipp; Chandrashaker, Akhila;

    2009-01-01

    Binding of epidermal growth factor (EGF) to its receptor leads to receptor dimerization, assembly of protein complexes, and activation of signaling networks that control key cellular responses. Despite their fundamental role in cell biology, little is known about protein complexes associated with...... the EGF receptor (EGFR) before growth factor stimulation. We used a modified membrane yeast two-hybrid system together with bioinformatics to identify 87 candidate proteins interacting with the ligand-unoccupied EGFR. Among them was histone deacetylase 6 (HDAC6), a cytoplasmic lysine deacetylase......, which we found negatively regulated EGFR endocytosis and degradation by controlling the acetylation status of alpha-tubulin and, subsequently, receptor trafficking along microtubules. A negative feedback loop consisting of EGFR-mediated phosphorylation of HDAC6 Tyr(570) resulted in reduced deacetylase...

  2. Nerve growth factor regulates synaptophysin expression in developing trigeminal ganglion neurons in vitro.

    Science.gov (United States)

    Tarsa, L; Balkowiec, A

    2009-02-01

    The role of neuronal growth factors in synaptic maturation of sensory neurons, including trigeminal ganglion (TG) neurons, remains poorly understood. Here, we show that nerve growth factor (NGF) regulates the intracellular distribution of the synaptic vesicle protein synaptophysin (Syp) in newborn rat TG neurons in vitro. While reducing the number of Syp-positive cell bodies, NGF dramatically increases Syp immunoreactivity in both proximal and distal segments of the neurite. Intriguingly, the increase in Syp immunoreactivity occurs only in neuron-enriched cultures, in which the number of non-neuronal cells is significantly reduced. Together, our data indicate that NGF is a candidate molecule involved in early postnatal maturation of TG neurons, including control of presynaptic assembly, and thereby formation of synaptic connections. PMID:19019428

  3. The polyadenylation factor subunit CLEAVAGE AND POLYADENYLATION SPECIFICITY FACTOR30: A key factor of programmed cell death and a regulator of immunity in arabidopsis

    KAUST Repository

    Bruggeman, Quentin

    2014-04-04

    Programmed cell death (PCD) is essential for several aspects of plant life, including development and stress responses. Indeed, incompatible plant-pathogen interactions are well known to induce the hypersensitive response, a localized cell death. Mutational analyses have identified several key PCD components, and we recently identified the mips1 mutant of Arabidopsis (Arabidopsis thaliana), which is deficient for the key enzyme catalyzing the limiting step of myoinositol synthesis. One of the most striking features of mips1 is the light-dependent formation of lesions on leaves due to salicylic acid (SA)-dependent PCD, revealing roles for myoinositol or inositol derivatives in the regulation of PCD. Here, we identified a regulator of plant PCD by screening for mutants that display transcriptomic profiles opposing that of the mips1 mutant. Our screen identified the oxt6 mutant, which has been described previously as being tolerant to oxidative stress. In the oxt6 mutant, a transfer DNA is inserted in the CLEAVAGE AND POLYADENYLATION SPECIFICITY FACTOR30 (CPSF30) gene, which encodes a polyadenylation factor subunit homolog. We show that CPSF30 is required for lesion formation in mips1 via SA-dependent signaling, that the prodeath function of CPSF30 is not mediated by changes in the glutathione status, and that CPSF30 activity is required for Pseudomonas syringae resistance. We also show that the oxt6 mutation suppresses cell death in other lesion-mimic mutants, including lesion-simulating disease1, mitogen-activated protein kinase4, constitutive expressor of pathogenesis-related genes5, and catalase2, suggesting that CPSF30 and, thus, the control of messenger RNA 3′ end processing, through the regulation of SA production, is a key component of plant immune responses. © 2014 American Society of Plant Biologists. All rights reserved.

  4. Exposure to Pre- and Perinatal Risk Factors Partially Explains Mean Differences in Self-Regulation between Races

    Science.gov (United States)

    Barnes, J. C.; Boutwell, Brian B.; Miller, J. Mitchell; DeShay, Rashaan A.; Beaver, Kevin M.; White, Norman

    2016-01-01

    Objectives To examine whether differential exposure to pre- and perinatal risk factors explained differences in levels of self-regulation between children of different races (White, Black, Hispanic, Asian, and Other). Methods Multiple regression models based on data from the Early Childhood Longitudinal Study, Birth Cohort (n ≈ 9,850) were used to analyze the impact of pre- and perinatal risk factors on the development of self-regulation at age 2 years. Results Racial differences in levels of self-regulation were observed. Racial differences were also observed for 9 of the 12 pre-/perinatal risk factors. Multiple regression analyses revealed that a portion of the racial differences in self-regulation was explained by differential exposure to several of the pre-/perinatal risk factors. Specifically, maternal age at childbirth, gestational timing, and the family’s socioeconomic status were significantly related to the child’s level of self-regulation. These factors accounted for a statistically significant portion of the racial differences observed in self-regulation. Conclusions The findings indicate racial differences in self-regulation may be, at least partially, explained by racial differences in exposure to pre- and perinatal risk factors. PMID:26882110

  5. The function and regulation of the GATA factor ELT-2 in the C. elegans endoderm.

    Science.gov (United States)

    Wiesenfahrt, Tobias; Berg, Janette Y; Osborne Nishimura, Erin; Robinson, Adam G; Goszczynski, Barbara; Lieb, Jason D; McGhee, James D

    2016-02-01

    ELT-2 is the major regulator of genes involved in differentiation, maintenance and function of C. elegans intestine from the early embryo to mature adult. elt-2 responds to overexpression of the GATA transcription factors END-1 and END-3, which specify the intestine, as well as to overexpression of the two GATA factors that are normally involved in intestinal differentiation, ELT-7 and ELT-2 itself. Little is known about the molecular mechanisms underlying these interactions, how ELT-2 levels are maintained throughout development or how such systems respond to developmental perturbations. Here, we analyse elt-2 gene regulation through transgenic reporter assays, ELT-2 ChIP and characterisation of in vitro DNA-protein interactions. Our results indicate that elt-2 is controlled by three discrete regulatory regions conserved between C. elegans and C. briggsae that span >4 kb of 5' flanking sequence. These regions are superficially interchangeable but have quantitatively different enhancer properties, and their combined activities indicate inter-region synergies. Their regulatory activity is mediated by a small number of conserved TGATAA sites that are largely interchangeable and interact with different endodermal GATA factors with only modest differences in affinity. The redundant molecular mechanism that forms the elt-2 regulatory network is robust and flexible, as loss of end-3 halves ELT-2 levels in the early embryo but levels fully recover by the time of hatching. When ELT-2 is expressed under the control of end-1 regulatory elements, in addition to its own endogenous promoter, it can replace the complete set of endoderm-specific GATA factors: END-1, END-3, ELT-7 and (the probably non-functional) ELT-4. Thus, in addition to controlling gene expression during differentiation, ELT-2 is capable of specifying the entire C. elegans endoderm. PMID:26700680

  6. fundTPL-2 – ERK1/2 Signaling Promotes Host Resistance against Intracellular Bacterial Infection by Negative Regulation of Type I Interferon Production3

    Science.gov (United States)

    McNab, Finlay W.; Ewbank, John; Rajsbaum, Ricardo; Stavropoulos, Evangelos; Martirosyan, Anna; Redford, Paul S.; Wu, Xuemei; Graham, Christine M.; Saraiva, Margarida; Tsichlis, Philip; Chaussabel, Damien; Ley, Steven C.; O’Garra, Anne

    2013-01-01

    Tuberculosis, caused by Mycobacterium tuberculosis (Mtb), remains a leading cause of mortality and morbidity worldwide, causing approximately 1.4 million deaths per year. Key immune components for host protection during tuberculosis include the cytokines IL-12, IL-1 and TNF-α, as well as IFN-γ and CD4+ Th1 cells. However, immune factors determining whether individuals control infection or progress to active tuberculosis are incompletely understood. Excess amounts of type I interferon have been linked to exacerbated disease during tuberculosis in mouse models and to active disease in patients, suggesting tight regulation of this family of cytokines is critical to host resistance. In addition, the immunosuppressive cytokine IL-10 is known to inhibit the immune response to Mtb in murine models through the negative regulation of key pro-inflammatory cytokines and the subsequent Th1 response. We show here, using a combination of transcriptomic analysis, genetics and pharmacological inhibitors that the TPL-2-ERK1/2 signaling pathway is important in mediating host resistance to tuberculosis through negative regulation of type I interferon production. The TPL-2-ERK1/2 signalling pathway regulated production by macrophages of several cytokines important in the immune response to Mtb as well as regulating induction of a large number of additional genes, many in a type I IFN dependent manner. In the absence of TPL-2 in vivo, excess type I interferon promoted IL-10 production and exacerbated disease. These findings describe an important regulatory mechanism for controlling tuberculosis and reveal mechanisms by which type I interferon may promote susceptibility to this important disease. PMID:23842752

  7. TPL-2-ERK1/2 signaling promotes host resistance against intracellular bacterial infection by negative regulation of type I IFN production.

    Science.gov (United States)

    McNab, Finlay W; Ewbank, John; Rajsbaum, Ricardo; Stavropoulos, Evangelos; Martirosyan, Anna; Redford, Paul S; Wu, Xuemei; Graham, Christine M; Saraiva, Margarida; Tsichlis, Philip; Chaussabel, Damien; Ley, Steven C; O'Garra, Anne

    2013-08-15

    Tuberculosis, caused by Mycobacterium tuberculosis, remains a leading cause of mortality and morbidity worldwide, causing ≈ 1.4 million deaths per year. Key immune components for host protection during tuberculosis include the cytokines IL-12, IL-1, and TNF-α, as well as IFN-γ and CD4(+) Th1 cells. However, immune factors determining whether individuals control infection or progress to active tuberculosis are incompletely understood. Excess amounts of type I IFN have been linked to exacerbated disease during tuberculosis in mouse models and to active disease in patients, suggesting tight regulation of this family of cytokines is critical to host resistance. In addition, the immunosuppressive cytokine IL-10 is known to inhibit the immune response to M. tuberculosis in murine models through the negative regulation of key proinflammatory cytokines and the subsequent Th1 response. We show in this study, using a combination of transcriptomic analysis, genetics, and pharmacological inhibitors, that the TPL-2-ERK1/2 signaling pathway is important in mediating host resistance to tuberculosis through negative regulation of type I IFN production. The TPL-2-ERK1/2 signaling pathway regulated production by macrophages of several cytokines important in the immune response to M. tuberculosis as well as regulating induction of a large number of additional genes, many in a type I IFN-dependent manner. In the absence of TPL-2 in vivo, excess type I IFN promoted IL-10 production and exacerbated disease. These findings describe an important regulatory mechanism for controlling tuberculosis and reveal mechanisms by which type I IFN may promote susceptibility to this important disease. PMID:23842752

  8. Crosstalk between nuclear factor I-C and transforming growth factor-β1 signaling regulates odontoblast differentiation and homeostasis.

    Directory of Open Access Journals (Sweden)

    Dong-Seol Lee

    Full Text Available Transforming growth factor-β1 (TGF-β1 signaling plays a key role in vertebrate development, homeostasis, and disease. Nuclear factor I-C (NFI-C has been implicated in TGF-β1 signaling, extracellular matrix gene transcription, and tooth root development. However, the functional relationship between NFI-C and TGF-β1 signaling remains uncharacterized. The purpose of this study was to identify the molecular interactions between NFI-C and TGF-β1 signaling in mouse odontoblasts. Real-time polymerase chain reaction and western analysis demonstrated that NFI-C expression levels were inversely proportional to levels of TGF-β1 signaling molecules during in vitro odontoblast differentiation. Western blot and immunofluorescence results showed that NFI-C was significantly degraded after TGF-β1 addition in odontoblasts, and the formation of the Smad3 complex was essential for NFI-C degradation. Additionally, ubiquitination assay results showed that Smurf1 and Smurf2 induced NFI-C degradation and polyubiquitination in a TGF-β1-dependent manner. Both kinase and in vitro binding assays revealed that the interaction between NFI-C and Smurf1/Smurf2 requires the activation of the mitogen-activated protein kinase pathway by TGF-β1. Moreover, degradation of NFI-C induced by TGF-β1 occurred generally in cell types other than odontoblasts in normal human breast epithelial cells. In contrast, NFI-C induced dephosphorylation of p-Smad2/3. These results show that crosstalk between NFI-C and TGF-β1 signaling regulates cell differentiation and homeostatic processes in odontoblasts, which might constitute a common cellular mechanism.

  9. The pluripotency factor Nanog regulates pericentromeric heterochromatin organization in mouse embryonic stem cells.

    Science.gov (United States)

    Novo, Clara Lopes; Tang, Calvin; Ahmed, Kashif; Djuric, Ugljesa; Fussner, Eden; Mullin, Nicholas P; Morgan, Natasha P; Hayre, Jasvinder; Sienerth, Arnold R; Elderkin, Sarah; Nishinakamura, Ryuichi; Chambers, Ian; Ellis, James; Bazett-Jones, David P; Rugg-Gunn, Peter J

    2016-05-01

    An open and decondensed chromatin organization is a defining property of pluripotency. Several epigenetic regulators have been implicated in maintaining an open chromatin organization, but how these processes are connected to the pluripotency network is unknown. Here, we identified a new role for the transcription factor NANOG as a key regulator connecting the pluripotency network with constitutive heterochromatin organization in mouse embryonic stem cells. Deletion of Nanog leads to chromatin compaction and the remodeling of heterochromatin domains. Forced expression of NANOG in epiblast stem cells is sufficient to decompact chromatin. NANOG associates with satellite repeats within heterochromatin domains, contributing to an architecture characterized by highly dispersed chromatin fibers, low levels of H3K9me3, and high major satellite transcription, and the strong transactivation domain of NANOG is required for this organization. The heterochromatin-associated protein SALL1 is a direct cofactor for NANOG, and loss of Sall1 recapitulates the Nanog-null phenotype, but the loss of Sall1 can be circumvented through direct recruitment of the NANOG transactivation domain to major satellites. These results establish a direct connection between the pluripotency network and chromatin organization and emphasize that maintaining an open heterochromatin architecture is a highly regulated process in embryonic stem cells. PMID:27125671

  10. Checkpoint Kinases Regulate a Global Network of Transcription Factors in Response to DNA Damage

    Directory of Open Access Journals (Sweden)

    Eric J. Jaehnig

    2013-07-01

    Full Text Available DNA damage activates checkpoint kinases that induce several downstream events, including widespread changes in transcription. However, the specific connections between the checkpoint kinases and downstream transcription factors (TFs are not well understood. Here, we integrate kinase mutant expression profiles, transcriptional regulatory interactions, and phosphoproteomics to map kinases and downstream TFs to transcriptional regulatory networks. Specifically, we investigate the role of the Saccharomyces cerevisiae checkpoint kinases (Mec1, Tel1, Chk1, Rad53, and Dun1 in the transcriptional response to DNA damage caused by methyl methanesulfonate. The result is a global kinase-TF regulatory network in which Mec1 and Tel1 signal through Rad53 to synergistically regulate the expression of more than 600 genes. This network involves at least nine TFs, many of which have Rad53-dependent phosphorylation sites, as regulators of checkpoint-kinase-dependent genes. We also identify a major DNA damage-induced transcriptional network that regulates stress response genes independently of the checkpoint kinases.

  11. Steroidogenic Factor 1 in the Ventromedial Nucleus of the Hypothalamus Regulates Age-Dependent Obesity.

    Science.gov (United States)

    Kinyua, Ann W; Yang, Dong Joo; Chang, Inik; Kim, Ki Woo

    2016-01-01

    The ventromedial nucleus of the hypothalamus (VMH) is important for the regulation of whole body energy homeostasis and lesions in the VMH are reported to result in massive weight gain. The nuclear receptor steroidogenic factor 1 (SF-1) is a known VMH marker as it is exclusively expressed in the VMH region of the brain. SF-1 plays a critical role not only in the development of VMH but also in its physiological functions. In this study, we generated prenatal VMH-specific SF-1 KO mice and investigated age-dependent energy homeostasis regulation by SF-1. Deletion of SF-1 in the VMH resulted in dysregulated insulin and leptin homeostasis and late onset obesity due to increased food intake under normal chow and high fat diet conditions. In addition, SF-1 ablation was accompanied by a marked reduction in energy expenditure and physical activity and this effect was significantly pronounced in the aged mice. Taken together, our data indicates that SF-1 is a key component in the VMH-mediated regulation of energy homeostasis and implies that SF-1 plays a protective role against metabolic stressors including aging and high fat diet. PMID:27598259

  12. Regulation of eukaryotic initiation factor 4AII by MyoD during murine myogenic cell differentiation.

    Directory of Open Access Journals (Sweden)

    Gabriela Galicia-Vázquez

    Full Text Available Gene expression during muscle cell differentiation is tightly regulated at multiple levels, including translation initiation. The PI3K/mTOR signalling pathway exerts control over protein synthesis by regulating assembly of eukaryotic initiation factor (eIF 4F, a heterotrimeric complex that stimulates recruitment of ribosomes to mRNA templates. One of the subunits of eIF4F, eIF4A, supplies essential helicase function during this phase of translation. The presence of two cellular eIF4A isoforms, eIF4AI and eIF4AII, has long thought to impart equivalent functions to eIF4F. However, recent experiments have alluded to distinct activities between them. Herein, we characterize distinct regulatory mechanisms between the eIF4A isoforms during muscle cell differentiation. We find that eIF4AI levels decrease during differentiation whereas eIF4AII levels increase during myofiber formation in a MyoD-dependent manner. This study characterizes a previously undefined mechanism for eIF4AII regulation in differentiation and highlights functional differences between eIF4AI and eIF4AII. Finally, RNAi-mediated alterations in eIF4AI and eIF4AII levels indicate that the myogenic process can tolerate short term reductions in eIF4AI or eIF4AII levels, but not both.

  13. Revisiting the mechanism of coagulation factor XIII activation and regulation from a structure/functional perspective.

    Science.gov (United States)

    Gupta, Sneha; Biswas, Arijit; Akhter, Mohammad Suhail; Krettler, Christoph; Reinhart, Christoph; Dodt, Johannes; Reuter, Andreas; Philippou, Helen; Ivaskevicius, Vytautas; Oldenburg, Johannes

    2016-01-01

    The activation and regulation of coagulation Factor XIII (FXIII) protein has been the subject of active research for the past three decades. Although discrete evidence exists on various aspects of FXIII activation and regulation a combinatorial structure/functional view in this regard is lacking. In this study, we present results of a structure/function study of the functional chain of events for FXIII. Our study shows how subtle chronological submolecular changes within calcium binding sites can bring about the detailed transformation of the zymogenic FXIII to its activated form especially in the context of FXIIIA and FXIIIB subunit interactions. We demonstrate what aspects of FXIII are important for the stabilization (first calcium binding site) of its zymogenic form and the possible modes of deactivation (thrombin mediated secondary cleavage) of the activated form. Our study for the first time provides a structural outlook of the FXIIIA2B2 heterotetramer assembly, its association and dissociation. The FXIIIB subunits regulatory role in the overall process has also been elaborated upon. In summary, this study provides detailed structural insight into the mechanisms of FXIII activation and regulation that can be used as a template for the development of future highly specific therapeutic inhibitors targeting FXIII in pathological conditions like thrombosis. PMID:27453290

  14. Developmentally Regulated Expression of the Nerve Growth Factor Receptor Gene in the Periphery and Brain

    Science.gov (United States)

    Buck, C. R.; Martinez, Humberto J.; Black, Ira B.; Chao, Moses V.

    1987-05-01

    Nerve growth factor (NGF) regulates development and maintenance of function of peripheral sympathetic and sensory neurons. A potential role for the trophic factor in brain has been detected only recently. The ability of a cell to respond to NGF is due, in part, to expression of specific receptors on the cell surface. To study tissue-specific expression of the NGF receptor gene, we have used sensitive cRNA probes for detection of NGF receptor mRNA. Our studies indicate that the receptor gene is selectively and specifically expressed in sympathetic (superior cervical) and sensory (dorsal root) ganglia in the periphery, and by the septum-basal forebrain centrally, in the neonatal rat in vivo. Moreover, examination of tissues from neonatal and adult rats reveals a marked reduction in steady-state NGF receptor mRNA levels in sensory ganglia. In contrast, a 2- to 4-fold increase was observed in the basal forebrain and in the sympathetic ganglia over the same time period. Our observations suggest that NGF receptor mRNA expression is developmentally regulated in specific areas of the nervous system in a differential fashion.

  15. Endoglin negatively regulates transforming growth factor beta1-induced profibrotic responses in intestinal fibroblasts.

    LENUS (Irish Health Repository)

    Burke, J P

    2012-02-01

    BACKGROUND: Fibroblasts isolated from strictures in Crohn\\'s disease (CD) exhibit reduced responsiveness to stimulation with transforming growth factor (TGF) beta1. TGF-beta1, acting through the smad pathway, is critical to fibroblast-mediated intestinal fibrosis. The membrane glycoprotein, endoglin, is a negative regulator of TGF-beta1. METHODS: Intestinal fibroblasts were cultured from seromuscular biopsies of patients undergoing intestinal resection for CD strictures or from control patients. Endoglin expression was assessed using confocal microscopy, flow cytometry and western blot. The effect of small interfering (si) RNA-mediated knockdown and plasmid-mediated overexpression of endoglin on fibroblast responsiveness to TGF-beta1 was assessed by examining smad phosphorylation, smad binding element (SBE) promoter activity, connective tissue growth factor (CTGF) expression and ability to contract collagen. RESULTS: Crohn\\'s stricture fibroblasts expressed increased constitutive cell-surface and whole-cell endoglin relative to control cells. Endoglin co-localized with filamentous actin. Fibroblasts treated with siRNA directed against endoglin exhibited enhanced TGF-beta1-mediated smad-3 phosphorylation, and collagen contraction. Cells transfected with an endoglin plasmid did not respond to TGF-beta1 by exhibiting SBE promoter activity or producing CTGF. CONCLUSION: Fibroblasts from strictures in CD express increased constitutive endoglin. Endoglin is a negative regulator of TGF-beta1 signalling in the intestinal fibroblast, modulating smad-3 phosphorylation, SBE promoter activity, CTGF production and collagen contraction.

  16. Utrophin up-regulation by an artificial transcription factor in transgenic mice.

    Directory of Open Access Journals (Sweden)

    Elisabetta Mattei

    Full Text Available Duchenne Muscular Dystrophy (DMD is a severe muscle degenerative disease, due to absence of dystrophin. There is currently no effective treatment for DMD. Our aim is to up-regulate the expression level of the dystrophin related gene utrophin in DMD, complementing in this way the lack of dystrophin functions. To this end we designed and engineered several synthetic zinc finger based transcription factors. In particular, we have previously shown that the artificial three zinc finger protein named Jazz, fused with the appropriate effector domain, is able to drive the transcription of a test gene from the utrophin promoter "A". Here we report on the characterization of Vp16-Jazz-transgenic mice that specifically over-express the utrophin gene at the muscular level. A Chromatin Immunoprecipitation assay (ChIP demonstrated the effective access/binding of the Jazz protein to active chromatin in mouse muscle and Vp16-Jazz was shown to be able to up-regulate endogenous utrophin gene expression by immunohistochemistry, western blot analyses and real-time PCR. To our knowledge, this is the first example of a transgenic mouse expressing an artificial gene coding for a zinc finger based transcription factor. The achievement of Vp16-Jazz transgenic mice validates the strategy of transcriptional targeting of endogenous genes and could represent an exclusive animal model for use in drug discovery and therapeutics.

  17. Tissue factor expression and methylation regulation in differentiation of embryonic stem cells into trophoblast

    Institute of Scientific and Technical Information of China (English)

    Lin-Xin Liu; Hui Zeng; En-Yi Liu; Fang-Ping Chen

    2014-01-01

    Objective:To explore tissue factor(TF) expression and methylation regulation in differentiation of human embryonic stem cells(hESCs) into trophoblast.Methods:Differentiation of hESCs into trophoblast was induced by bone morphogenetic protein4(BMP4).Expression of gene, protein of TF andDNA methylation at different time points during induction process was detected byRT-PCT,Western blot, flow cytometry andMSP-PCR method.Results:The expression of mRNA, protein level ofTF could be detected during directional differentiation of hESCs to trophoblast cells, semi methylation-semi non methylation expression appeared atTFDNA promoter region, and it showed decreased methylation level and increased non methylation level with formation of trophoblast cell and increased expression ofTF.Conclusions:It shows that during differentiation of hESCs into trophoblast, the differential expression ofTF is related withDNA methylation level, and it is changed with the methylation or non methylated degree.It provids new platform to furtherly explore the regulation mechanisms of specific expression of tissue factor in the process of the embryonic stem cell development.

  18. A role for the autophagy regulator Transcription Factor EB in amiodarone-induced phospholipidosis.

    Science.gov (United States)

    Buratta, Sandra; Urbanelli, Lorena; Ferrara, Giuseppina; Sagini, Krizia; Goracci, Laura; Emiliani, Carla

    2015-06-01

    The antiarrhythmic agent amiodarone, a cationic amphiphilic drug, is known to induce phospholipidosis, i.e. the accumulation of phospholipids within lysosomal structures to give multi-lamellar inclusion bodies. Despite the concerns raised about phospholipidosis in the recent years, the molecular mechanisms underlying amiodarone- or other cationic amphiphilic drug-induced phospholipidosis are still under investigation. Here we demonstrated that amiodarone doses able to induce phospholiposis according to NBD-PC uptake assay (1-12 μM, 24 h) activates Transcription Factor EB (TFEB), a pivotal regulator of the autophagic pathway, in human HepG2 cells. Further evidences confirmed the effect of amiodarone on the autophagic-lysosomal system in HepG2 and BEAS-2B cells: lysosomal β-hexosaminidase isoenzymes secretion, transcriptional up-regulation of the lysosomal β-hexosaminidase α-subunit, alteration of cathepsin B, D and L intracellular maturation in a cell- and protease-specific manner. Autophagy activation was also demonstrated by increased conversion of LC3-I into LC3-II and reduced phosphorylation of the mTORC1 target S6 kinase. Besides, we provided evidence that TFEB over-expression prevents amiodarone-induced phospholipid accumulation, suggesting that this transcription factor could be a possible target to develop strategies for phospholipidosis attenuation. PMID:25881747

  19. Kruppel-like factor 4 regulates intestinal epithelial cell morphology and polarity.

    Directory of Open Access Journals (Sweden)

    Tianxin Yu

    Full Text Available Krüppel-like factor 4 (KLF4 is a zinc finger transcription factor that plays a vital role in regulating cell lineage differentiation during development and maintaining epithelial homeostasis in the intestine. In normal intestine, KLF4 is predominantly expressed in the differentiated epithelial cells. It has been identified as a tumor suppressor in colorectal cancer. KLF4 knockout mice demonstrated a decrease in number of goblet cells in the colon, and conditional ablation of KLF4 from the intestinal epithelium led to altered epithelial homeostasis. However, the role of KLF4 in differentiated intestinal cells and colon cancer cells, as well as the mechanism by which it regulates homeostasis and represses tumorigenesis in the intestine is not well understood. In our study, KLF4 was partially depleted in the differentiated intestinal epithelial cells by a tamoxifen-inducible Cre recombinase. We found a significant increase in the number of goblet cells in the KLF4-deleted small intestine, suggesting that KLF4 is not only required for goblet cell differentiation, but also required for maintaining goblet cell numbers through its function in inhibiting cell proliferation. The number and position of Paneth cells also changed. This is consistent with the KLF4 knockout study using villin-Cre [1]. Through immunohistochemistry (IHC staining and statistical analysis, we found that a stem cell and/or tuft cell marker, DCAMKL1, and a proliferation marker, Ki67, are affected by KLF4 depletion, while an enteroendocrine cell marker, neurotensin (NT, was not affected. In addition, we found KLF4 depletion altered the morphology and polarity of the intestinal epithelial cells. Using a three-dimensional (3D intestinal epithelial cyst formation assay, we found that KLF4 is essential for cell polarity and crypt-cyst formation in human colon cancer cells. These findings suggest that, as a tumor suppressor in colorectal cancer, KLF4 affects intestinal epithelial cell

  20. Human mitochondrial transcription factor A functions in both nuclei and mitochondria and regulates cancer cell growth

    International Nuclear Information System (INIS)

    Highlights: → Mitochondrial transcription factor A (mtTFA) localizes in nuclei and binds tightly to the nuclear chromatin. → mtTFA contains two putative nuclear localization signals (NLS) in the HMG-boxes. → Overexpression of mtTFA enhances the growth of cancer cells, whereas downregulation of mtTFA inhibits their growth by regulating mtTFA target genes, such as baculoviral IAP repeat-containing 5 (BIRC5; also known as survivin). → Knockdown of mtTFA expression induces p21-dependent G1 cell cycle arrest. -- Abstract: Mitochondrial transcription factor A (mtTFA) is one of the high mobility group protein family and is required for both transcription from and maintenance of mitochondrial genomes. However, the roles of mtTFA have not been extensively studied in cancer cells. Here, we firstly reported the nuclear localization of mtTFA. The proportion of nuclear-localized mtTFA varied among different cancer cells. Some mtTFA binds tightly to the nuclear chromatin. DNA microarray and chromatin immunoprecipitation assays showed that mtTFA can regulate the expression of nuclear genes. Overexpression of mtTFA enhanced the growth of cancer cell lines, whereas downregulation of mtTFA inhibited their growth by regulating mtTFA target genes, such as baculoviral IAP repeat-containing 5 (BIRC5; also known as survivin). Knockdown of mtTFA expression induced p21-dependent G1 cell cycle arrest. These results imply that mtTFA functions in both nuclei and mitochondria to promote cell growth.

  1. The B-cell identity factor Pax5 regulates distinct transcriptional programmes in early and late B lymphopoiesis

    OpenAIRE

    Revilla-i-Domingo, Roger; Bilic, Ivan; Vilagos, Bojan; Tagoh, Hiromi; Ebert, Anja; Tamir, Ido M.; Smeenk, Leonie; Trupke, Johanna; Sommer, Andreas; Jaritz, Markus; Busslinger, Meinrad

    2012-01-01

    Genome-wide sequencing approaches reveal that the transcription factor Pax5 controls the identity and function of B cells by regulating the expression of distinct target genes in pro-B and mature B cells.

  2. The Pseudomonas aeruginosa rmlBDAC operon, encoding dTDP-L-rhamnose biosynthetic enzymes, is regulated by the quorum-sensing transcriptional regulator RhlR and the alternative sigma factor σS.

    Science.gov (United States)

    Aguirre-Ramírez, Marisela; Medina, Gerardo; González-Valdez, Abigail; Grosso-Becerra, Victoria; Soberón-Chávez, Gloria

    2012-04-01

    Pseudomonas aeruginosa produces as biosurfactants rhamnolipids, containing one (mono-rhamnolipid) or two (di-rhamnolipid) l-rhamnose molecules. The rhamnosyltransferase RhlB catalyses the synthesis of mono-rhamnolipid using as precursors dTDP-l-rhamnose and 3-(3-hydroxyalkanoyloxy)alkanoic acids (HAAs) produced by RhlA, while the rhamnosyltransferase RhlC synthesizes di-rhamnolipid using mono-rhamnolipid and dTDP-l-rhamnose as substrates. The Las and Rhl quorum-sensing systems coordinately regulate the production of these surfactants, as well as that of other exoproducts involved in bacterial virulence, at the transcriptional level in a cell density-dependent manner. In this work we study the transcriptional regulation of the rmlBDAC operon, encoding the enzymes involved in the production of dTDP-l-rhamnose, the substrate of both rhamnosyltransferases, RhlB and RhlC, and also a component of P. aeruginosa lipopolysaccharide. Here we show that the rmlBDAC operon possesses three promoters. One of these transcriptional start sites (P2) is responsible for most of its expression and is dependent on the stationary phase sigma factor σ(S) and on RhlR/C(4)-HSL through its binding to an atypical 'las box'. PMID:22262098

  3. Antisense epidermal growth factor receptor RNA transfection in human glioblastoma cells down-regulates telomerase activity and telomere length

    OpenAIRE

    Tian, X-X; Pang, JC-S; J. Zheng; Chen, J; To, S S T; Ng, H-K

    2002-01-01

    Epidermal growth factor receptor is overexpressed and/or amplified in up to 50% of glioblastomas, suggesting an important role of this gene in glial tumorigenesis and progression. In the present study we demonstrated that epidermal growth factor receptor is involved in regulation of telomerase activity in glioblastoma. Antisense-epidermal growth factor receptor approach was used to inhibit epidermal growth factor receptor expression of glioblastoma U87MG cells. Telomerase activity in antisens...

  4. CXCL1 can be regulated by IL-6 and promotes granulocyte adhesion to brain capillaries during bacterial toxin exposure and encephalomyelitis

    Directory of Open Access Journals (Sweden)

    Roy Monica

    2012-01-01

    Full Text Available Abstract Background Granulocytes generally exert protective roles in the central nervous system (CNS, but recent studies suggest that they can be detrimental in experimental autoimmune encephalomyelitis (EAE, the most common model of multiple sclerosis. While the cytokines and adhesion molecules involved in granulocyte adhesion to the brain vasculature have started to be elucidated, the required chemokines remain undetermined. Methods CXCR2 ligand expression was examined in the CNS of mice suffering from EAE or exposed to bacterial toxins by quantitative RT-PCR and in situ hybridization. CXCL1 expression was analyzed in IL-6-treated endothelial cell cultures by quantitative RT-PCR and ELISA. Granulocytes were counted in the brain vasculature after treatment with a neutralizing anti-CXCL1 antibody using stereological techniques. Results CXCL1 was the most highly expressed ligand of the granulocyte receptor CXCR2 in the CNS of mice subjected to EAE or infused with lipopolysaccharide (LPS or pertussis toxin (PTX, the latter being commonly used to induce EAE. IL-6 upregulated CXCL1 expression in brain endothelial cells by acting transcriptionally and mediated the stimulatory effect of PTX on CXCL1 expression. The anti-CXCL1 antibody reduced granulocyte adhesion to brain capillaries in the three conditions under study. Importantly, it attenuated EAE severity when given daily for a week during the effector phase of the disease. Conclusions This study identifies CXCL1 not only as a key regulator of granulocyte recruitment into the CNS, but also as a new potential target for the treatment of neuroinflammatory diseases such as multiple sclerosis.

  5. The transcription factor Lc-Maf participates in Col27a1 regulation during chondrocyte maturation

    International Nuclear Information System (INIS)

    The transcription factor Lc-Maf, which is a splice variant of c-Maf, is expressed in cartilage undergoing endochondral ossification and participates in the regulation of type II collagen through a cartilage-specific Col2a1 enhancer element. Type XXVII and type XI collagens are also expressed in cartilage during endochondral ossification, and so enhancer/reporter assays were used to determine whether Lc-Maf could regulate cartilage-specific enhancers from the Col27a1 and Col11a2 genes. The Col27a1 enhancer was upregulated over 4-fold by Lc-Maf, while the Col11a2 enhancer was downregulated slightly. To confirm the results of these reporter assays, rat chondrosarcoma (RCS) cells were transiently transfected with an Lc-Maf expression plasmid, and quantitative RT-PCR was performed to measure the expression of endogenous Col27a1 and Col11a2 genes. Endogenous Col27a1 was upregulated 6-fold by Lc-Maf overexpression, while endogenous Col11a2 was unchanged. Finally, in situ hybridization and immunohistochemistry were performed in the radius and ulna of embryonic day 17 mouse forelimbs undergoing endochondral ossification. Results demonstrated that Lc-Maf and Col27a1 mRNAs are coexpressed in proliferating and prehypertrophic regions, as would be predicted if Lc-Maf regulates Col27a1 expression. Type XXVII collagen protein was also most abundant in prehypertrophic and proliferating chondrocytes. Others have shown that mice that are null for Lc-Maf and c-Maf have expanded hypertrophic regions with reduced ossification and delayed vascularization. Separate studies have indicated that Col27a1 may serve as a scaffold for ossification and vascularization. The work presented here suggests that Lc-Maf may affect the process of endochondral ossification by participating in the regulation of Col27a1 expression.

  6. Deciphering human heat shock transcription factor 1 regulation via post-translational modification in yeast.

    Directory of Open Access Journals (Sweden)

    Liliana Batista-Nascimento

    Full Text Available Heat shock transcription factor 1 (HSF1 plays an important role in the cellular response to proteotoxic stresses. Under normal growth conditions HSF1 is repressed as an inactive monomer in part through post-translation modifications that include protein acetylation, sumoylation and phosphorylation. Upon exposure to stress HSF1 homotrimerizes, accumulates in nucleus, binds DNA, becomes hyper-phosphorylated and activates the expression of stress response genes. While HSF1 and the mechanisms that regulate its activity have been studied for over two decades, our understanding of HSF1 regulation remains incomplete. As previous studies have shown that HSF1 and the heat shock response promoter element (HSE are generally structurally conserved from yeast to metazoans, we have made use of the genetically tractable budding yeast as a facile assay system to further understand the mechanisms that regulate human HSF1 through phosphorylation of serine 303. We show that when human HSF1 is expressed in yeast its phosphorylation at S303 is promoted by the MAP-kinase Slt2 independent of a priming event at S307 previously believed to be a prerequisite. Furthermore, we show that phosphorylation at S303 in yeast and mammalian cells occurs independent of GSK3, the kinase primarily thought to be responsible for S303 phosphorylation. Lastly, while previous studies have suggested that S303 phosphorylation represses HSF1-dependent transactivation, we now show that S303 phosphorylation also represses HSF1 multimerization in both yeast and mammalian cells. Taken together, these studies suggest that yeast cells will be a powerful experimental tool for deciphering aspects of human HSF1 regulation by post-translational modifications.

  7. Snail transcription factor negatively regulates maspin tumor suppressor in human prostate cancer cells

    International Nuclear Information System (INIS)

    Maspin, a putative tumor suppressor that is down-regulated in breast and prostate cancer, has been associated with decreased cell motility. Snail transcription factor is a zinc finger protein that is increased in breast cancer and is associated with increased tumor motility and invasion by induction of epithelial-mesenchymal transition (EMT). We investigated the molecular mechanisms by which Snail increases tumor motility and invasion utilizing prostate cancer cells. Expression levels were analyzed by RT-PCR and western blot analyses. Cell motility and invasion assays were performed, while Snail regulation and binding to maspin promoter was analyzed by luciferase reporter and chromatin immunoprecipitation (ChIP) assays. Snail protein expression was higher in different prostate cancer cells lines as compared to normal prostate epithelial cells, which correlated inversely with maspin expression. Snail overexpression in 22Rv1 prostate cancer cells inhibited maspin expression and led to increased migration and invasion. Knockdown of Snail in DU145 and C4-2 cancer cells resulted in up-regulation of maspin expression, concomitant with decreased migration. Transfection of Snail into 22Rv1 or LNCaP cells inhibited maspin promoter activity, while stable knockdown of Snail in C4-2 cells increased promoter activity. ChIP analysis showed that Snail is recruited to the maspin promoter in 22Rv1 cells. Overall, this is the first report showing that Snail can negatively regulate maspin expression by directly repressing maspin promoter activity, leading to increased cell migration and invasion. Therefore, therapeutic targeting of Snail may be useful to re-induce expression of maspin tumor suppressor and prevent prostate cancer tumor progression

  8. Cell Cycle-dependent Regulation of the Forkhead Transcription Factor FOXK2 by CDK·Cyclin Complexes*

    OpenAIRE

    Marais, Anett; Ji, Zongling; Child, Emma S.; Krause, Eberhard; Mann, David J.; Sharrocks, Andrew D.

    2010-01-01

    Several mammalian forkhead transcription factors have been shown to impact on cell cycle regulation and are themselves linked to cell cycle control systems. Here we have investigated the little studied mammalian forkhead transcription factor FOXK2 and demonstrate that it is subject to control by cell cycle-regulated protein kinases. FOXK2 exhibits a periodic rise in its phosphorylation levels during the cell cycle, with hyperphosphorylation occurring in mitotic cells. Hyperphosphorylation occ...

  9. RNA sequencing analysis of gene expression regulated by the transcription factor SlZFP2 during early fruit development

    OpenAIRE

    Weng, Lin; Zhao, Fangfang; Li, Rong; Xiao, Han

    2016-01-01

    The transcription factor SlZFP2 (Solanum lycopersicum Zinc Finger Protein 2) regulates ABA biosynthesis during fruit development. To reveal the regulatory network of this transcription factor, we conducted a high-throughput RNA-seq to identify differentially expressed genes in 2 dpa (days post anthesis) fruits from a representative RNAi line in Solanum pimpinellifolium LA1589 background and the wild type. The transcriptome analysis revealed that expression of 2722 genes was regulated by SlZFP...

  10. Chronic methamphetamine administration causes differential regulation of transcription factors in the rat midbrain.

    Directory of Open Access Journals (Sweden)

    Irina N Krasnova

    Full Text Available Methamphetamine (METH is an addictive and neurotoxic psychostimulant widely abused in the USA and throughout the world. When administered in large doses, METH can cause depletion of striatal dopamine terminals, with preservation of midbrain dopaminergic neurons. Because alterations in the expression of transcription factors that regulate the development of dopaminergic neurons might be involved in protecting these neurons after toxic insults, we tested the possibility that their expression might be affected by toxic doses of METH in the adult brain. Male Sprague-Dawley rats pretreated with saline or increasing doses of METH were challenged with toxic doses of the drug and euthanized two weeks later. Animals that received toxic METH challenges showed decreases in dopamine levels and reductions in tyrosine hydroxylase protein concentration in the striatum. METH pretreatment protected against loss of striatal dopamine and tyrosine hydroxylase. In contrast, METH challenges caused decreases in dopamine transporters in both saline- and METH-pretreated animals. Interestingly, METH challenges elicited increases in dopamine transporter mRNA levels in the midbrain in the presence but not in the absence of METH pretreatment. Moreover, toxic METH doses caused decreases in the expression of the dopamine developmental factors, Shh, Lmx1b, and Nurr1, but not in the levels of Otx2 and Pitx3, in saline-pretreated rats. METH pretreatment followed by METH challenges also decreased Nurr1 but increased Otx2 and Pitx3 expression in the midbrain. These findings suggest that, in adult animals, toxic doses of METH can differentially influence the expression of transcription factors involved in the developmental regulation of dopamine neurons. The combined increases in Otx2 and Pitx3 expression after METH preconditioning might represent, in part, some of the mechanisms that served to protect against METH-induced striatal dopamine depletion observed after METH

  11. Hypoxia-inducible factor regulates expression of surfactant protein in alveolar type II cells in vitro.

    Science.gov (United States)

    Ito, Yoko; Ahmad, Aftab; Kewley, Emily; Mason, Robert J

    2011-11-01

    Alveolar type II (ATII) cells cultured at an air-liquid (A/L) interface maintain differentiation, but they lose these properties when they are submerged. Others showed that an oxygen tension gradient develops in the culture medium as ATII cells consume oxygen. Therefore, we wondered whether hypoxia inducible factor (HIF) signaling could explain differences in the phenotypes of ATII cells cultured under A/L interface or submerged conditions. ATII cells were isolated from male Sprague-Dawley rats and cultured on inserts coated with a mixture of rat-tail collagen and Matrigel, in medium including 5% rat serum and 10 ng/ml keratinocyte growth factor, with their apical surfaces either exposed to air or submerged. The A/L interface condition maintained the expression of surfactant proteins, whereas that expression was down-regulated under the submerged condition, and the effect was rapid and reversible. Under submerged conditions, there was an increase in HIF1α and HIF2α in nuclear extracts, mRNA levels of HIF inducible genes, vascular endothelial growth factor, glucose transporter-1 (GLUT1), and the protein level of pyruvate dehydrogenase kinase isozyme-1. The expression of surfactant proteins was suppressed and GLUT1 mRNA levels were induced when cells were cultured with 1 mM dimethyloxalyl glycine. The expression of surfactant proteins was restored under submerged conditions with supplemented 60% oxygen. HIF signaling and oxygen tension at the surface of cells appears to be important in regulating the phenotype of rat ATII cells. PMID:21454802

  12. COX-2 gene expression in colon cancer tissue related to regulating factors and promoter methylation status

    International Nuclear Information System (INIS)

    Increased cyclooxygenase activity promotes progression of colorectal cancer, but the mechanisms behind COX-2 induction remain elusive. This study was therefore aimed to define external cell signaling and transcription factors relating to high COX-2 expression in colon cancer tissue. Tumor and normal colon tissue were collected at primary curative operation in 48 unselected patients. COX-2 expression in tumor and normal colon tissue was quantified including microarray analyses on tumor mRNA accounting for high and low tumor COX-2 expression. Cross hybridization was performed between tumor and normal colon tissue. Methylation status of up-stream COX-2 promoter region was evaluated. Tumors with high COX-2 expression displayed large differences in gene expression compared to normal colon. Numerous genes with altered expression appeared in tumors of high COX-2 expression compared to tumors of low COX-2. COX-2 expression in normal colon was increased in patients with tumors of high COX-2 compared to normal colon from patients with tumors of low COX-2. IL1β, IL6 and iNOS transcripts were up-regulated among external cell signaling factors; nine transcription factors (ATF3, C/EBP, c-Fos, Fos-B, JDP2, JunB, c-Maf, NF-κB, TCF4) showed increased expression and 5 (AP-2, CBP, Elk-1, p53, PEA3) were decreased in tumors with high COX-2. The promoter region of COX-2 gene did not show consistent methylation in tumor or normal colon tissue. Transcription and external cell signaling factors are altered as covariates to COX-2 expression in colon cancer tissue, but DNA methylation of the COX-2 promoter region was not a significant factor behind COX-2 expression in tumor and normal colon tissue

  13. Transcriptional regulation of mouse PXR gene: an interplay of transregulatory factors.

    Directory of Open Access Journals (Sweden)

    Sangeeta Kumari

    Full Text Available Pregnane X Receptor (PXR is an important ligand-activated nuclear receptor functioning as a 'master regulator' of expression of phase I, phase II drug metabolizing enzymes, and members of the drug transporters. PXR is primarily expressed in hepatic tissues and to lesser extent in other non-hepatic tissues both in human and in mice. Although its expression profile is well studied but little is known about the regulatory mechanisms that govern PXR gene expression in these cells. In the present study, we have cloned and characterized over 5 kb (-4963 to +54 region lying upstream of mouse PXR transcription start site. Promoter-reporter assays revealed that the proximal promoter region of up to 1 kb is sufficient to support the expression of PXR in the mouse liver cell lines. It was evident that the 500 bp proximal promoter region contains active binding sites for Ets, Tcf, Ikarose and nuclear factor families of transcription factors. Electrophoretic mobility shift assays demonstrated that the minimal region of 134 bp PXR promoter was able to bind Ets-1 and β-catenin proteins. This result was further confirmed by chromatin immunoprecipitation analysis. In summary, the present study identified a promoter region of mouse PXR gene and the transregulatory factors responsible for PXR promoter activity. The results presented herein are expected to provide important cues to gain further insight into the regulatory mechanisms of PXR function.

  14. Structures of HSF2 Reveal Mechanisms for Differential Regulation of Human Heat Shock Factors

    Science.gov (United States)

    Jaeger, Alex M.; Pemble, Charles W.; Sistonen, Lea; Thiele, Dennis J.

    2016-01-01

    Heat Shock Transcription Factor (HSF) family members function in stress protection and in human disease including proteopathies, neurodegeneration and cancer. The mechanisms that drive distinct post-translational modifications, co-factor recruitment and target gene activation for specific HSF paralogs are unknown. We present high-resolution crystal structures of the human HSF2 DNA-binding domain (DBD) bound to DNA, revealing an unprecedented view of HSFs that provides insights into their unique biology. The HSF2 DBD structures resolve a novel carboxyl-terminal helix that directs the coiled-coil domain to wrap around DNA, exposing paralog-specific sequences of the DBD surface, for differential post-translational modifications and co-factor interactions. We further demonstrate a direct interaction between HSF1 and HSF2 through their coiled-coil domains. Together, these features provide a new model for HSF structure as the basis for differential and combinatorial regulation to influence the transcriptional response to cellular stress. PMID:26727490

  15. Iron regulation of the major virulence factors in the AIDS-associated pathogen Cryptococcus neoformans.

    Directory of Open Access Journals (Sweden)

    Won Hee Jung

    2006-11-01

    Full Text Available Iron overload is known to exacerbate many infectious diseases, and conversely, iron withholding is an important defense strategy for mammalian hosts. Iron is a critical cue for Cryptococcus neoformans because the fungus senses iron to regulate elaboration of the polysaccharide capsule that is the major virulence factor during infection. Excess iron exacerbates experimental cryptococcosis and the prevalence of this disease in Sub-Saharan Africa has been associated with nutritional and genetic aspects of iron loading in the background of the HIV/AIDS epidemic. We demonstrate that the iron-responsive transcription factor Cir1 in Cr. neoformans controls the regulon of genes for iron acquisition such that cir1 mutants are "blind" to changes in external iron levels. Cir1 also controls the known major virulence factors of the pathogen including the capsule, the formation of the anti-oxidant melanin in the cell wall, and the ability to grow at host body temperature. Thus, the fungus is remarkably tuned to perceive iron as part of the disease process, as confirmed by the avirulence of the cir1 mutant; this characteristic of the pathogen may provide opportunities for antifungal treatment.

  16. The transcription factor IRF3 triggers “defensive suicide” necrosis in response to viral and bacterial pathogens

    OpenAIRE

    Nelson C. Di Paolo; Konstantin Doronin; Lisa K. Baldwin; Thalia Papayannopoulou; Dmitry M. Shayakhmetov

    2013-01-01

    Although molecular components that execute non-inflammatory apoptotic cell death are well defined, molecular pathways that trigger necrotic cell death remain poorly characterized. Here we show that in response to infection with adenovirus or Listeria monocytogenes, macrophages in vivo undergo rapid pro-inflammatory necrotic death that is controlled by interferon-regulatory factor 3 (IRF3). The transcriptional activity of IRF3 is, surprisingly, not required for the induction of necrosis, and i...

  17. Ecological factors characterizing the prevalence of bacterial tick-borne pathogens in Ixodes ricinus ticks in pastures and woodlands

    OpenAIRE

    Halos, Lenaïg; Bord, Severine; Cotté, Violaine; Gasqui, Patrick; Abrial, David; Barnouin, Jacques; Boulouis, Henri-Jean; Taussat, Muriel; Vourc'H, Gwenaël

    2010-01-01

    Ecological changes are recognized as an important driver behind the emergence of infectious diseases. The prevalence of infection in ticks depends upon ecological factors that are rarely taken into account simultaneously. Our objective was to investigate the influences of forest fragmentation, vegetation, adult tick hosts, and habitat on the infection prevalence of three tick-borne bacteria, Borrelia burgdorferi sensu lato, Anaplasma phagocytophilum, and Rickettsia sp. of the spotted fever gr...

  18. DNA transfer occurs during a cell surface contact stage of F sex factor-mediated bacterial conjugation.

    OpenAIRE

    Panicker, M M; Minkley, E G

    1985-01-01

    Donor bacteria containing JCFL39, a temperature-sensitive traD mutant of the F sex factor, were used at the nonpermissive temperature to accumulate stable mating pairs with recipient cells. At this stage in conjugation, extracellular F pili were removed by treatment with 0.01% sodium dodecyl sulfate. Upon then shifting to the permissive temperature for JCFL39, transfer of the F plasmid was observed. The mating pairs that were accumulated with JCFL39 at the nonpermissive temperature were readi...

  19. Factors predisposing to acute and recurrent bacterial non-necrotizing cellulitis in hospitalized patients: a prospective case-control study.

    Science.gov (United States)

    Karppelin, M; Siljander, T; Vuopio-Varkila, J; Kere, J; Huhtala, H; Vuento, R; Jussila, T; Syrjänen, J

    2010-06-01

    Acute non-necrotizing cellulitis is a skin infection with a tendency to recur. Both general and local risk factors for erysipelas or cellulitis have been recognized in previous studies using hospitalized controls. The aim of this study was to identify risk factors for cellulitis using controls recruited from the general population. We also compared patients with a history of previous cellulitis with those suffering a single episode, with regard to the risk factors: length of stay in hospital, duration of fever, and inflammatory response as measured by C-reactive protein (CRP) level and leukocyte count. Ninety hospitalized cellulitis patients and 90 population controls matched for age and sex were interviewed and clinically examined during the period April 2004 to March 2005. In multivariate analysis, chronic oedema of the extremity, disruption of the cutaneous barrier and obesity were independently associated with acute cellulitis. Forty-four (49%) patients had a positive history (PH) of at least one cellulitis episode before entering the study. Obesity and previous ipsilateral surgical procedure were statistically significantly more common in PH patients, whereas a recent (<1 month) traumatic wound was more common in patients with a negative history (NH) of cellulitis. PH patients had longer duration of fever and hospital stay, and their CRP and leukocyte values more often peaked at a high level than those of NH patients. Oedema, broken skin and obesity are risk factors for acute cellulitis. The inflammatory response as indicated by CRP level and leukocyte count is statistically significantly more severe in PH than NH patients. PMID:19694769

  20. Regulation of insulin-like growth factor binding protein-1 (IGFBP-1) and implications in catabolic conditions

    OpenAIRE

    Lindgren, Björn

    1997-01-01

    This thesis has studied the regulation of IGFBP-1 (insulin-like growth factor binding protein 1), which is one factor regulating the bioavailability of IGF-I with special interest how IGFBP-1 is regulated in vitro and in humans, especially in diabetes and catabolic conditions. The IGFBP-1 cDNA was cloned and used for studies in human hepatoma cells, HepG2, which showed that both insulin and IGF-I could decrease IGFBP-1 in the cell conditioned medium. IGF-I inhibited also IGF...