The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform

Lianhui Zhang - One of the best experts on this subject based on the ideXlab platform.

  • xanthomonas campestris Cell Cell Communication involves a putative nucleotide receptor protein clp and a hierarchical signalling network
    Molecular Microbiology, 2007
    Co-Authors: Yawen He, Lianhui Wang, Yihu Dong, Alvin Yujin Ng, Min Xu, Lianhui Zhang
    Abstract:

    Summary The bacterial pathogen Xanthomonas campestris pv. campestris co-ordinates virulence factor production and biofilm dispersal through a diffusible signal factor (DSF)-mediated Cell–Cell Communication mechanism. The RpfC/RpfG two-component system plays a key role in DSF signal transduction and appears to modulate downstream DSF regulon by changing intraCellular content of cyclic dimeric GMP (c-di-GMP), an unusual nucleotide second messenger. Here we show that Clp, a conserved global regulator showing a strong homology to the cAMP nucleotide receptor protein Crp of Escherichia coli, is essential for DSF regulation of virulence factor production but not for biofilm dispersal. Deletion of clp in Xcc changed the transcriptional expression of 299 genes including a few encoding transcription factors. Further genetic and microarray analysis led to identification of a homologue of the transcriptional regulator Zur, and a novel TetR-type transcription factor FhrR. These two regulatory factors regulated different sets of genes within Clp regulon. These results outline a hierarchical signalling network by which DSF modulates different biological functions, and may also provide a clue on how the novel nucleotide signal can be coupled to its downstream regulatory networks.

  • genome scale analysis of diffusible signal factor regulon in xanthomonas campestris pv campestris identification of novel Cell Cell Communication dependent genes and functions
    Molecular Microbiology, 2006
    Co-Authors: Yawen He, Lianhui Wang, Yihu Dong, Min Xu, Yujin Alvin Ng, Haibao Zhang, Lianhui Zhang
    Abstract:

    Summary The bacterial pathogen Xanthomonas campestris pv. campestris ( Xcc ) recruits a diffusible signal factor (DSF), which has recently been structurally character- ized as cis -11-methyl-2-dodecenoic acid, as a Cell- Cell Communication signal to synchronize virulence gene expression and biofilm dispersal. In this study, we showed that despite the existance of phenotype variations in different Xcc isolates, the DSF-mediated functions were in general conserved. To investigate the genomic profiles of DSF regulation, we designed and conducted oligomicroarray analysis by compari- son of the gene expression patterns of wild-type strain XC1 and its DSF-deficient mutant XC1dF, as well as those of XC1dF in the presence or absence of DSF signals. The analyses led to identification of 165 genes, whose expression was significantly influenced by DSF signals. These genes encode proteins and enzymes belonging to at least 12 functional groups. In addition to those previously known DSF-dependent activities such as production of extraCellular enzymes and extraCellular polysaccharides, microarray analy- ses also revealed new functions mediated by DSF, such as flagellum synthesis, resistance to toxins and oxidative stress, and aerobic respiration. Phenotype analyses confirmed that DSF signalling contributed to resistance to toxin acriflavin and hydrogen peroxide, and to the survival of bacterial Cells at different tem- peratures. We conclude that DSF Cell-Cell signalling is not only essential for co-ordinating the expression of virulence genes but also plays a vital role in keep- ing up the general competence of the pathogen in ecosystems.

  • a bacterial Cell Cell Communication signal with cross kingdom structural analogues
    Molecular Microbiology, 2003
    Co-Authors: Lianhui Wang, Yunfeng Gao, Yihu Dong, Su Xing Wang, Lixing Weng, Leng Tay, Rongxiang Fang, Lianhui Zhang
    Abstract:

    ExtraCellular signals are the key components of microbial Cell-Cell Communication systems. This report identified a diffusible signal factor (DSF), which regulates virulence in Xanthomonas campestris pv. campestris, as cis-11-methyl-2-dodecenoic acid, an alpha,beta unsaturated fatty acid. Analysis of DSF derivatives established the double bond at the alpha,beta positions as the most important structural feature for DSF biological activity. A range of bacterial pathogens, including several Mycobacterium species, also displayed DSF-like activity. Furthermore, DSF is structurally and functionally related to farnesoic acid (FA), which regulates morphological transition and virulence by Candida albicans, a fungal pathogen. Similar to FA, which is also an alpha,beta unsaturated fatty acid, DSF inhibits the dimorphic transition of C. albicans at a physiologically relevant concentration. We conclude that alpha,beta unsaturated fatty acids represent a new class of extraCellular signals for bacterial and fungal Cell-Cell Communications. As prokaryote-eukaryote interactions are ubiquitous, such cross-kingdom conservation in Cell-Cell Communication systems might have significant ecological and economic importance.

Scott Herness - One of the best experts on this subject based on the ideXlab platform.

  • the neuropeptides cck and npy and the changing view of Cell to Cell Communication in the taste bud
    Physiology & Behavior, 2009
    Co-Authors: Scott Herness, Fangli Zhao
    Abstract:

    The evolving view of the taste bud increasingly suggests that it operates as a complex signal processing unit. A number of neurotransmitters and neuropeptides and their corresponding receptors are now known to be expressed in subsets of taste receptor Cells in the mammalian bud. These expression patterns set up hard-wired Cell-to-Cell Communication pathways whose exact physiological roles still remain obscure. As occurs in other Cellular systems, it is likely that neuropeptides are co-expressed with neurotransmitters and function as neuromodulators. Several neuropeptides have been identified in taste receptor Cells including cholecystokinin (CCK), neuropeptide Y (NPY), vasoactive intestinal peptide (VIP), and glucagon-like peptide 1 (GLP-1). Of these, CCK and NPY are the best studied. These two peptides are co-expressed in the same presynaptic Cells; however, their postsynaptic actions are both divergent and antagonistic. CCK and its receptor, the CCK-1 subtype, are expressed in the same subset of taste receptor Cells and the autocrine activation of these Cells produces a number of excitatory physiological actions. Further, most of these Cells are responsive to bitter stimuli. On the other hand, NPY and its receptor, the NPY-1 subtype, are expressed in different Cells. NPY, acting in a paracrine fashion on NPY-1 receptors, results in inhibitory actions on the Cell. Preliminary evidence suggests the NPY-1 receptor expressing Cell co-expresses T1R3, a member of the T1R family of G-protein coupled receptors thought to be important in detection of sweet and umami stimuli. Thus the neuropeptide expressing Cells co-express CCK, NPY, and CCK-1 receptor. Neuropeptides released from these Cells during bitter stimulation may work in concert to both modulate the excitation of bitter-sensitive taste receptor Cells while concurrently inhibiting sweet-sensitive Cells. This modulatory process is similar to the phenomenon of lateral inhibition that occurs in other sensory systems.

  • gaba expression in the mammalian taste bud functions as a route of inhibitory Cell to Cell Communication
    Proceedings of the National Academy of Sciences of the United States of America, 2009
    Co-Authors: Yu Cao, Fangli Zhao, T N Kolli, Randy Hivley, Scott Herness
    Abstract:

    Recent advances have underscored Cell-to-Cell Communication as an important component of the operation of taste buds with individual taste receptor Cells (TRCs) communicating with one another by means of a number of neurotransmitters and neuropeptides, although functional roles are not yet understood. Here, we characterize the presence, distribution pattern, phenotype, and functional consequences of a previously undescribed inhibitory route within the taste bud mediated by the classic neurotransmitter GABA and its receptors. By using immunocytochemistry, subsets of TRCs within rat taste buds were identified as expressing GABA, and its synthetic enzyme glutamate decarboxylase (GAD). GAD expression was verified with Western blotting. Immunofluorescent studies revealed complex coexpression patterns of GAD with the TRC protein markers gustducin, neural Cell adhesion molecule, protein gene product 9.5, and synaptosomal-associated protein of 25 kDa that collectively outline hardwired signaling pathways of GABAergic TRCs. RT-PCR and immunocytochemistry demonstrated that both GABAA and GABAB receptors are expressed in the taste bud. The later was observed in a subset TRCs paracrine to GAD-expressing TRCs. Physiological effects of GABA were examined by patch clamp recordings. GABA and the GABAA agonists muscimol and isoguvacine enhanced isolated chloride currents in a dose-dependent manner. Also, GABA and the GABAB agonist baclofen both elicited increases of the inwardly rectifying potassium currents that could be blocked by the GABAB receptor antagonist CGP 35348 and the G protein blocker GDP-βS. Collectively, these data suggest that GABAergic TRCs are able to shape the final chemosensory output of the bud by means of processes of Cell-to-Cell modulation.

Peter J. Prentis - One of the best experts on this subject based on the ideXlab platform.

  • The Rapid Regenerative Response of a Model Sea Anemone Species Exaiptasia pallida Is Characterised by Tissue Plasticity and Highly Coordinated Cell Communication
    Marine Biotechnology, 2020
    Co-Authors: Chloé A. Van Der Burg, Ana Pavasovic, Edward K. Gilding, Elise S. Pelzer, Joachim M. Surm, Hayden L. Smith, Terence P. Walsh, Peter J. Prentis
    Abstract:

    Regeneration of a limb or tissue can be achieved through multiple different pathways and mechanisms. The sea anemone Exaiptasia pallida has been observed to have exCellent regenerative proficiency, but this has not yet been described transcriptionally. In this study, we examined the genetic expression changes during a regenerative timecourse and reported key genes involved in regeneration and wound healing. We found that the major response was an early (within the first 8 h) upregulation of genes involved in Cellular movement and Cell Communication, which likely contribute to a high level of tissue plasticity resulting in the rapid regeneration response observed in this species. We find the immune system was only transcriptionally active in the first 8 h post-amputation and conclude, in accordance with previous literature, that the immune system and regeneration have an inverse relationship. Fifty-nine genes (3.8% of total) differentially expressed during regeneration were identified as having no orthologues in other species, indicating that regeneration in E. pallida may rely on the activation of species-specific novel genes. Additionally, taxonomically restricted novel genes, including species-specific novels, and highly conserved genes were identified throughout the regenerative timecourse, showing that both may work in concert to achieve complete regeneration.

  • The rapid regenerative response of a model sea anemone species Exaiptasia pallida is characterised by tissue plasticity and highly coordinated Cell Communication
    2019
    Co-Authors: Chloé A. Van Der Burg, Ana Pavasovic, Edward K. Gilding, Elise S. Pelzer, Joachim M. Surm, Terence P. Walsh, Peter J. Prentis
    Abstract:

    Regeneration of a limb or tissue can be achieved through multiple different pathways and mechanisms. The sea anemone Exaiptasia pallida has been observed to have exCellent regenerative proficiency but this has not yet been described transcriptionally. In this study we examined the genetic expression changes during a regenerative timecourse and report key genes involved in regeneration and wound healing. We found that the major response was an early upregulation of genes involved in Cellular movement and Cell Communication, which likely contribute to a high level of tissue plasticity resulting in the rapid regeneration response observed in this species. We find the immune system is only transcriptionally active in the first eight hours post-amputation and conclude, in accordance with previous literature, that the immune system and regeneration have an inverse relationship. Fifty-nine genes (3.8% of total) differentially expressed during regeneration were identified as having no orthologues in other species, indicating that regeneration in E. pallida may rely on the activation of species-specific novel genes. Additionally, taxonomically-restricted novel genes, including species-specific novels, and highly conserved genes were identified throughout the regenerative timecourse, showing that both may work in concert to achieve complete regeneration. We conclude that E. pallida behaves similarly to other anemone species such as Nematostella vectensis and Calliactis polypus but with some notable novel differences.

Darren Gilmour - One of the best experts on this subject based on the ideXlab platform.

  • luminal signalling links Cell Communication to tissue architecture during organogenesis
    Nature, 2014
    Co-Authors: Sevi Durdu, Murat Iskar, Celine Revenu, Nicole L Schieber, Andreas Kunze, Peer Bork, Yannick Schwab, Darren Gilmour
    Abstract:

    Groups of Cells within a migrating collective assemble shared luminal cavities that trap and concentrate the signalling molecule fibroblast growth factor, providing a self-organising mechanism to focus and coordinate Cell Communication within tissues. The developing embryo assembles complex tissues and organs through the coordinated differentiation of Cell groups, a collective process that depends on highly efficient Cell Communication. How Cells in growing tissues exert control on morphogens that direct their fate and are secreted into extraCellular spaces has been unclear. Using live imaging Darren Gilmour and colleagues show that Cells in the developing lateral line system of zebrafish arrange themselves in shared microenvironments or microlumina so that signals — such as fibroblast growth factor (FGF) — are more concentrated in some areas than in others. This allows a coordinated response from nearby Cells according to their position, a feedback process that in turn influences the arrangement of the Cells and propels further development. Morphogenesis is the process whereby Cell collectives are shaped into differentiated tissues and organs1. The self-organizing nature of morphogenesis has been recently demonstrated by studies showing that stem Cells in three-dimensional culture can generate complex organoids, such as mini-guts2, optic-cups3 and even mini-brains4. To achieve this, Cell collectives must regulate the activity of secreted signalling molecules that control Cell differentiation, presumably through the self-assembly of microenvironments or niches. However, mechanisms that allow changes in tissue architecture to feedback directly on the activity of extraCellular signals have not been described. Here we investigate how the process of tissue assembly controls signalling activity during organogenesis in vivo, using the migrating zebrafish lateral line primordium5. We show that fibroblast growth factor (FGF) activity within the tissue controls the frequency at which it deposits rosette-like mechanosensory organs. Live imaging reveals that FGF becomes specifically concentrated in microluminal structures that assemble at the centre of these organs and spatially constrain its signalling activity. Genetic inhibition of microlumen assembly and laser micropuncture experiments demonstrate that microlumina increase signalling responses in participating Cells, thus allowing FGF to coordinate the migratory behaviour of Cell groups at the tissue rear. As the formation of a central lumen is a self-organizing property of many Cell types, such as epithelia6 and embryonic stem Cells7, luminal signalling provides a potentially general mechanism to locally restrict, coordinate and enhance Cell Communication within tissues.

  • luminal signalling links Cell Communication to tissue architecture during organogenesis
    Nature, 2014
    Co-Authors: Sevi Durdu, Murat Iskar, Celine Revenu, Nicole L Schieber, Andreas Kunze, Peer Bork, Yannick Schwab, Darren Gilmour
    Abstract:

    Morphogenesis is the process whereby Cell collectives are shaped into differentiated tissues and organs. The self-organizing nature of morphogenesis has been recently demonstrated by studies showing that stem Cells in three-dimensional culture can generate complex organoids, such as mini-guts, optic-cups and even mini-brains. To achieve this, Cell collectives must regulate the activity of secreted signalling molecules that control Cell differentiation, presumably through the self-assembly of microenvironments or niches. However, mechanisms that allow changes in tissue architecture to feedback directly on the activity of extraCellular signals have not been described. Here we investigate how the process of tissue assembly controls signalling activity during organogenesis in vivo, using the migrating zebrafish lateral line primordium. We show that fibroblast growth factor (FGF) activity within the tissue controls the frequency at which it deposits rosette-like mechanosensory organs. Live imaging reveals that FGF becomes specifically concentrated in microluminal structures that assemble at the centre of these organs and spatially constrain its signalling activity. Genetic inhibition of microlumen assembly and laser micropuncture experiments demonstrate that microlumina increase signalling responses in participating Cells, thus allowing FGF to coordinate the migratory behaviour of Cell groups at the tissue rear. As the formation of a central lumen is a self-organizing property of many Cell types, such as epithelia and embryonic stem Cells, luminal signalling provides a potentially general mechanism to locally restrict, coordinate and enhance Cell Communication within tissues.

Peggy Myung - One of the best experts on this subject based on the ideXlab platform.

  • hardwiring stem Cell Communication through tissue structure
    Cell, 2016
    Co-Authors: Tianchi Xin, Valentina Greco, Peggy Myung
    Abstract:

    Adult stem Cells across diverse organs self-renew and differentiate to maintain tissue homeostasis. How stem Cells receive input to preserve tissue structure and function largely relies on their Communication with surrounding Cellular and non-Cellular elements. As such, how tissues are organized and patterned not only reflects organ function, but also inherently hardwires networks of Communication between stem Cells and their environment to direct tissue homeostasis and injury repair. This review highlights how different methods of stem Cell Communication reflect the unique organization and function of diverse tissues.