Die verband tussen genade en werke in 1QS se reddingsbegrip

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J.W. Semmelink

1995-09-01

Full Text Available The relationship between faith and works in the soteriology of 1QS. An analysis was made of 1QS to construct its view on grace and works in salvation. The author contends that Qumran makes much of works and that E P Sanders understated this element. Salvation according to 1QS can best be described by the modem term "synergism".

Bacterial tower of Babel --How cheating and lying diversify bacterial communication

Science.gov (United States)

Eldar, Avigdor

2012-02-01

In microbial ``quorum sensing'' (QS) communication systems, microbes produce and respond to a signaling molecule, enabling a cooperative response at high cell densities. Many species of bacteria show fast, intraspecific, evolutionary divergence of their QS pathway specificity---signaling molecules activate cognate receptors in the same strain but fail to activate, and sometimes inhibit, those of other strains. Despite many molecular studies, it has remained unclear how a signaling molecule and receptor can coevolve, what maintains diversity, and what drives the evolution of cross-inhibition. Here I use mathematical analysis to show that when QS controls the production of extracellular enzymes ---``public goods''---diversification can readily evolve. Coevolution is positively selected by cycles of alternating ``cheating'' receptor mutations and ``cheating immunity'' signaling mutations. The maintenance of diversity and the evolution of cross-inhibition between strains are facilitated by facultative cheating between the competing strains. My results suggest a role for complex social strategies in the long-term evolution of QS systems. More generally, my model of QS divergence suggests a form of kin recognition where different kin types coexist in unstructured populations.

The THE-QS World University Rankings, 2004 – 2009

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Richard Holmes

2010-06-01

Full Text Available This paper reviews the origin, development and demise of the Times Higher Education Supplement (now Times Higher Education – QS Quacquarelli Symonds (QS World University Rankings between 2004 and 2009. It describes the structure and methodology of the rankings, their public impact and various criticisms that have been made. It also analyses changes that were introduced between 2005 and 2009 and concludes by noting the development of two distinct ranking systems by the magazine Times Higher Education (THE and by its former partner, the consulting company Quacquarelli Symonds.

50 CFR 680.40 - Crab Quota Share (QS), Processor QS (PQS), Individual Fishing Quota (IFQ), and Individual...

Science.gov (United States)

2010-10-01

..., DEPARTMENT OF COMMERCE (CONTINUED) SHELLFISH FISHERIES OF THE EXCLUSIVE ECONOMIC ZONE OFF ALASKA Quota... the Internet or requested from the Regional Administrator. (ii) An application for crab QS or PQS may... be notified by an IAD, that the applicant did not meet the burden of proof to change the information...

Pseudomonas cremoricolorata Strain ND07 Produces N-acyl Homoserine Lactones as Quorum Sensing Molecules

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Nina Yusrina Muhamad Yunos

2014-06-01

Full Text Available Quorum sensing (QS is a bacterial cell-to-cell communication system controlling QS-mediated genes which is synchronized with the population density. The regulation of specific gene activity is dependent on the signaling molecules produced, namely N-acyl homoserine lactones (AHLs. We report here the identification and characterization of AHLs produced by bacterial strain ND07 isolated from a Malaysian fresh water sample. Molecular identification showed that strain ND07 is clustered closely to Pseudomonas cremoricolorata. Spent culture supernatant extract of P. cremoricolorata strain ND07 activated the AHL biosensor Chromobacterium violaceum CV026. Using high resolution triple quadrupole liquid chromatography-mass spectrometry, it was confirmed that P. cremoricolorata strain ND07 produced N-octanoyl-l-homoserine lactone (C8-HSL and N-decanoyl-l-homoserine lactone (C10-HSL. To the best of our knowledge, this is the first documentation on the production of C10-HSL in P. cremoricolorata strain ND07.

QS Spiral: Visualizing Periodic Quantified Self Data

DEFF Research Database (Denmark)

Larsen, Jakob Eg; Cuttone, Andrea; Jørgensen, Sune Lehmann

2013-01-01

In this paper we propose an interactive visualization technique QS Spiral that aims to capture the periodic properties of quantified self data and let the user explore those recurring patterns. The approach is based on time-series data visualized as a spiral structure. The interactivity includes ...

Ascorbic Acid-Induced Cardiac Differentiation of Murine Pluripotent Stem Cells: Transcriptional Profiling and Effect of a Small Molecule Synergist of Wnt/β-Catenin Signaling Pathway

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Dina Ivanyuk

2015-05-01

Full Text Available Background: Reproducible and efficient differentiation of pluripotent stem cells (PSCs to cardiomyocytes (CMs is essential for their use in regenerative medicine, drug testing and disease modeling. The aim of this study was to evaluate the effect of some previously reported cardiogenic substances on cardiac differentiation of mouse PSCs. Methods: Differentiation was performed by embryoid body (EB-based method using three different murine PSC lines. The differentiation efficiency was monitored by RT-qPCR, immunocytochemistry and flow cytometry, and the effect mechanistically evaluated by transcriptome analysis of treated EBs. Results: Among the five tested compounds (ascorbic acid, dorsomorphin, cyclic adenosine 3',5'-monophosphate, cardiogenol C, cyclosporin A only ascorbic acid (AA exerted a strong and reproducible cardiogenic effect in CGR8 cells which was less consistent in other two PSC lines. AA induced only minor changes in transcriptome of CGR8 cells after administration during the initial two days of differentiation. Cardiospecific genes and transcripts involved in angiogenesis, erythropoiesis and hematopoiesis were up-regulated on day 5 but not on days 2 or 3 of differentiation. The cardiac differentiation efficiency was improved when QS11, a small-molecule synergist of Wnt/β-catenin signaling pathway, was added to cultures after AA-treatment. Conclusion: This study demonstrates that only minor transcriptional changes are sufficient for enhancement of cardiogenesis of murine PSCs by AA and that AA and QS11 exhibit synergistic effects and enhance the efficiency of CM differentiation of murine PSCs.

TSH Receptor Signaling Abrogation by a Novel Small Molecule.

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Latif, Rauf; Realubit, Ronald B; Karan, Charles; Mezei, Mihaly; Davies, Terry F

2016-01-01

Pathological activation of the thyroid-stimulating hormone receptor (TSHR) is caused by thyroid-stimulating antibodies in patients with Graves' disease (GD) or by somatic and rare genomic mutations that enhance constitutive activation of the receptor influencing both G protein and non-G protein signaling. Potential selective small molecule antagonists represent novel therapeutic compounds for abrogation of such abnormal TSHR signaling. In this study, we describe the identification and in vitro characterization of a novel small molecule antagonist by high-throughput screening (HTS). The identification of the TSHR antagonist was performed using a transcription-based TSH-inhibition bioassay. TSHR-expressing CHO cells, which also expressed a luciferase-tagged CRE response element, were optimized using bovine TSH as the activator, in a 384 well plate format, which had a Z score of 0.3-0.6. Using this HTS assay, we screened a diverse library of ~80,000 compounds at a final concentration of 16.7 μM. The selection criteria for a positive hit were based on a mean signal threshold of ≥50% inhibition of control TSH stimulation. The screening resulted in 450 positive hits giving a hit ratio of 0.56%. A secondary confirmation screen against TSH and forskolin - a post receptor activator of adenylyl cyclase - confirmed one TSHR-specific candidate antagonist molecule (named VA-K-14). This lead molecule had an IC 50 of 12.3 μM and a unique chemical structure. A parallel analysis for cell viability indicated that the lead inhibitor was non-cytotoxic at its effective concentrations. In silico docking studies performed using a TSHR transmembrane model showed the hydrophobic contact locations and the possible mode of inhibition of TSHR signaling. Furthermore, this molecule was capable of inhibiting TSHR stimulation by GD patient sera and monoclonal-stimulating TSHR antibodies. In conclusion, we report the identification of a novel small molecule TSHR inhibitor, which has the

The crowded magnetosphere of the post common envelope binary QS Virginis

OpenAIRE

Parsons, S. G.; Hill, C. A.; Marsh, T. R.; Gansicke, B. T.; Watson, C. A.; Steeghs, D.; Dhillon, V. S.; Littlefair, S. P.; Copperwheat, C. M.; Schreiber, M. R.; Zorotovic, M.

2016-01-01

We present high-speed photometry and high-resolution spectroscopy of the eclipsing post-common-envelope binary QS Virginis (QS Vir). Our Ultraviolet and Visual Echelle Spectrograph (UVES) spectra span multiple orbits over more than a year and reveal the presence of several large prominences passing in front of both the M star and its white dwarf companion, allowing us to triangulate their positions. Despite showing small variations on a time-scale of days, they persist for more than a year an...

Skeletonized wave-equation Qs tomography using surface waves

KAUST Repository

Li, Jing; Dutta, Gaurav; Schuster, Gerard T.

2017-01-01

We present a skeletonized inversion method that inverts surface-wave data for the Qs quality factor. Similar to the inversion of dispersion curves for the S-wave velocity model, the complicated surface-wave arrivals are skeletonized as simpler data

Influences of excluded volume of molecules on signaling processes on the biomembrane.

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Masashi Fujii

Full Text Available We investigate the influences of the excluded volume of molecules on biochemical reaction processes on 2-dimensional surfaces using a model of signal transduction processes on biomembranes. We perform simulations of the 2-dimensional cell-based model, which describes the reactions and diffusion of the receptors, signaling proteins, target proteins, and crowders on the cell membrane. The signaling proteins are activated by receptors, and these activated signaling proteins activate target proteins that bind autonomously from the cytoplasm to the membrane, and unbind from the membrane if activated. If the target proteins bind frequently, the volume fraction of molecules on the membrane becomes so large that the excluded volume of the molecules for the reaction and diffusion dynamics cannot be negligible. We find that such excluded volume effects of the molecules induce non-trivial variations of the signal flow, defined as the activation frequency of target proteins, as follows. With an increase in the binding rate of target proteins, the signal flow varies by i monotonically increasing; ii increasing then decreasing in a bell-shaped curve; or iii increasing, decreasing, then increasing in an S-shaped curve. We further demonstrate that the excluded volume of molecules influences the hierarchical molecular distributions throughout the reaction processes. In particular, when the system exhibits a large signal flow, the signaling proteins tend to surround the receptors to form receptor-signaling protein clusters, and the target proteins tend to become distributed around such clusters. To explain these phenomena, we analyze the stochastic model of the local motions of molecules around the receptor.

Development of a minimal saponin vaccine adjuvant based on QS-21

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Fernández-Tejada, Alberto; Chea, Eric K.; George, Constantine; Pillarsetty, Nagavarakishore; Gardner, Jeffrey R.; Livingston, Philip O.; Ragupathi, Govind; Lewis, Jason S.; Tan, Derek S.; Gin, David Y.

2014-07-01

Adjuvants are materials added to vaccines to enhance the immunological response to an antigen. QS-21 is a natural product adjuvant under investigation in numerous vaccine clinical trials, but its use is constrained by scarcity, toxicity, instability and an enigmatic molecular mechanism of action. Herein we describe the development of a minimal QS-21 analogue that decouples adjuvant activity from toxicity and provides a powerful platform for mechanistic investigations. We found that the entire branched trisaccharide domain of QS-21 is dispensable for adjuvant activity and that the C4-aldehyde substituent, previously proposed to bind covalently to an unknown cellular target, is also not required. Biodistribution studies revealed that active adjuvants were retained preferentially at the injection site and the nearest draining lymph nodes compared with the attenuated variants. Overall, these studies have yielded critical insights into saponin structure-function relationships, provided practical synthetic access to non-toxic adjuvants, and established a platform for detailed mechanistic studies.

ASPMT(QS): Non-Monotonic Spatial Reasoning with Answer Set Programming Modulo Theories

OpenAIRE

Wałęga, Przemysław Andrzej; Bhatt, Mehul; Schultz, Carl

2015-01-01

The systematic modelling of \\emph{dynamic spatial systems} [9] is a key requirement in a wide range of application areas such as comonsense cognitive robotics, computer-aided architecture design, dynamic geographic information systems. We present ASPMT(QS), a novel approach and fully-implemented prototype for non-monotonic spatial reasoning ---a crucial requirement within dynamic spatial systems-- based on Answer Set Programming Modulo Theories (ASPMT). ASPMT(QS) consists of a (qualitative) s...

The Quantified Self (QS) Movement and Some Emerging Opportunities for the Educational Technology Field

Science.gov (United States)

Lee, Victor R.

2013-01-01

The Quantified Self (QS) movement is a growing global effort to use new mobile and wearable technologies to automatically obtain personal data about everyday activities. The social and material infrastructure associated with the Quantified Self (QS) movement provides a number of ideas that educational technologists should consider incorporating…

Role of chrysin on expression of insulin signaling molecules

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Kottireddy Satyanarayana

2015-01-01

Full Text Available Background: Currently available drugs are unsuccessful for the treatment of tye-2 diabetes due to their adverseside-effects. Hence, a search for novel drugs, especially ofplant origin, continues. Chrysin (5,7-dihydroxyflavone is a flavonoid, natural component of traditional medicinal herbs, present in honey, propolis and many plant extracts that hasbeen used in traditional medicine around the world to treat numerous ailments. Objective: The present study was aimed to identify the protective role of chrysin on the expression of insulin-signaling molecules in the skeletal muscle of high fat and sucrose-induced type-2 diabetic adult male rats. Materials and Methods: The oral effective dose of chrysin (100 mg/kg body weight was given once a day until the end of the study (30 days post-induction of diabetes to high fat diet-induced diabetic rats.At the end of the experimental period, fasting blood glucose, oral glucose tolerance, serum lipid profile, lipid peroxidation (LPO and free radical generation, as well as the levels of insulin signaling molecules and tissue glycogen in the gastrocnemius muscle were assessed. Results: Diabetic rats showed impaired glucose tolerance and impairment in insulin signaling molecules (IR, IRS-1, p-IRS-1Tyr 632 , p- Akt Thr308 , glucose transporter subtype 4 [GLUT4] proteins and glycogen concentration. Serum insulin, lipid profile, LPO and free radical generation were found to be increased in diabetic control rats.The treatment with chrysin normalized the altered levels of blood glucose, serum insulin, lipid profile, LPO and insulin signaling molecules as well as GLUT4 proteins. Conclusion: Our present findings indicate that chrysin improves glycemic control through activation of insulin signal transduction in the gastrocnemius muscle of high fat and sucrose-induced type-2 diabetic male rats.

The physical basis of bacterial quorum communication

CERN Document Server

2015-01-01

This book aims to educate physical scientists and quantitatively-oriented biologists on the application of physical experimentation and analysis, together with appropriate modeling, to understanding and interpreting microbial chemical communication and especially quorum sensing (QS). Quorum sensing describes a chemical communication behavior that is nearly universal among bacteria. Individual cells release a diffusible small molecule (an autoinducer) into their environment. A high concentration of this autoinducer serves as a signal of high population density, triggering new patterns of gene expression throughout the population. However QS is often much more complex than simple census-taking. Many QS bacteria produce and detect multiple autoinducers, which generate quorum signal cross talk with each other and with other bacterial species. QS gene regulatory networks operate in physically complex environments and respond to a range of inputs in addition to autoinducer signals. While many individual QS systems ...

Signal transduction by the major histocompatibility complex class I molecule

DEFF Research Database (Denmark)

Pedersen, A E; Skov, Svend; Bregenholt, S

1999-01-01

Ligation of cell surface major histocompatibility class I (MHC-I) proteins by antibodies, or by their native counter receptor, the CD8 molecule, mediates transduction of signals into the cells. MHC-I-mediated signaling can lead to both increased and decreased activity of the MHC-I-expressing cell...... and functioning, MHC-I molecules might be of importance for the maintenance of cellular homeostasis not only within the immune system, but also in the interplay between the immune system and other organ systems....

Quorum sensing Inhibitors as anti-pathogenic drugs

DEFF Research Database (Denmark)

Rasmussen, Thomas Bovbjerg; Givskov, Michael Christian

2006-01-01

as well as elevated tolerance to the activity of the innate immune system. Gram-negative bacteria commonly use N-acyl homoserine lactones (AHL) as QS signal molecules. The use of signal molecule based drugs to attenuate bacterial pathogenecity rather than bacterial growth is attractive for several reasons......, particularly considering the emergence of increasingly antibiotic-resistant bacteria. Compounds capable of this type of interference have been termed anti-pathogenic drugs. A large variety of synthetic AHL analogues and natural products libraries have been screened and a number of QS inhibitors (QSI) have been...

Quorum sensing in Acinetobacter: with special emphasis on antibiotic resistance, biofilm formation and quorum quenching

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Bindu Subhadra

2016-02-01

Full Text Available Acinetobacter is an important nosocomial, opportunistic human pathogen that is gradually gaining more attention as a major health threat worldwide. Quorum sensing (QS is a cell-cell communication system in which specific signaling molecules called autoinducers accumulate in the medium as the population density grows and control various physiological processes including production of virulence factors, biofilm and development of antibiotic resistance. The complex QS machinery in Acinetobacter is mediated by a two-component system which is homologous to the typical LuxI/LuxR system found in Gram-negative bacteria. This cell signaling system comprises of a sensor protein that functions as autoinducer synthase and a receptor protein which binds to the signal molecules, acyl homoserine lactones inducing a cascade of reactions. Lately, disruption of QS has emerged as an anti-virulence strategy with great therapeutic potential. Here, we depict the current understanding of the existing QS network in Acinetobacter and describe important anti-virulent strategies developed in order to effectively tackle this pathogen. In addition, the prospects of quorum quenching to control Acinetobacter infections is also been discussed.

Improved quorum sensing capacity by culturing Vibrio harveyi in microcapsules.

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Gao, Meng; Song, Huiyi; Liu, Xiudong; Yu, Weiting; Ma, Xiaojun

2016-04-01

Microcapsule entrapped low density cells with culture (ELDCwc), different from free cell culture, conferred stronger stress resistance and improved cell viability of microorganisms. In this paper, the quorum sensing (QS) system of Vibrio harveyi was used to investigate changes when cells were cultured in microcapsules. Cells in ELDCwc group grew into cell aggregates, which facilitated cell-cell communication and led to increased bioluminescence intensity. Moreover, the luxS-AI-2 system, a well-studied QS signal pathway, was detected as both luxS gene and the AI-2 signaling molecule, and the results were analyzed with respect to QS capacity of unit cell. The V. harveyi of ELDCwc also showed higher relative gene expression and stronger quorum sensing capacity when compared with free cells. In conclusion, the confined microcapsule space can promote the cell aggregates formation, reduce cell-cell communication distance and increase local concentration of signal molecule, which are beneficial to bacterial QS. Copyright © 2015 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Gram-Negative Bacterial Sensors for Eukaryotic Signal Molecules

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Olivier Lesouhaitier

2009-09-01

Full Text Available Ample evidence exists showing that eukaryotic signal molecules synthesized and released by the host can activate the virulence of opportunistic pathogens. The sensitivity of prokaryotes to host signal molecules requires the presence of bacterial sensors. These prokaryotic sensors, or receptors, have a double function: stereospecific recognition in a complex environment and transduction of the message in order to initiate bacterial physiological modifications. As messengers are generally unable to freely cross the bacterial membrane, they require either the presence of sensors anchored in the membrane or transporters allowing direct recognition inside the bacterial cytoplasm. Since the discovery of quorum sensing, it was established that the production of virulence factors by bacteria is tightly growth-phase regulated. It is now obvious that expression of bacterial virulence is also controlled by detection of the eukaryotic messengers released in the micro-environment as endocrine or neuro-endocrine modulators. In the presence of host physiological stress many eukaryotic factors are released and detected by Gram-negative bacteria which in return rapidly adapt their physiology. For instance, Pseudomonas aeruginosa can bind elements of the host immune system such as interferon-γ and dynorphin and then through quorum sensing circuitry enhance its virulence. Escherichia coli sensitivity to the neurohormones of the catecholamines family appears relayed by a recently identified bacterial adrenergic receptor. In the present review, we will describe the mechanisms by which various eukaryotic signal molecules produced by host may activate Gram-negative bacteria virulence. Particular attention will be paid to Pseudomonas, a genus whose representative species, P. aeruginosa, is a common opportunistic pathogen. The discussion will be particularly focused on the pivotal role played by these new types of pathogen sensors from the sensing to the transduction

Peptide pheromone signaling in Streptococcus and Enterococcus

Science.gov (United States)

Cook, Laura C.; Federle, Michael J.

2014-01-01

Intercellular chemical signaling in bacteria, commonly referred to as quorum sensing (QS), relies on the production and detection of compounds known as pheromones to elicit coordinated responses among members of a community. Pheromones produced by Gram-positive bacteria are comprised of small peptides. Based on both peptide structure and sensory system architectures, Gram-positive bacterial signaling pathways may be classified into one of four groups with a defining hallmark: cyclical peptides of the Agr type, peptides that contain Gly-Gly processing motifs, sensory systems of the RNPP family, or the recently characterized Rgg-like regulatory family. The recent discovery that Rgg family members respond to peptide pheromones increases substantially the number of species in which QS is likely a key regulatory component. These pathways control a variety of fundamental behaviors including conjugation, natural competence for transformation, biofilm development, and virulence factor regulation. Overlapping QS pathways found in multiple species and pathways that utilize conserved peptide pheromones provide opportunities for interspecies communication. Here we review pheromone signaling identified in the genera Enterococcus and Streptococcus, providing examples of all four types of pathways. PMID:24118108

QsMYB1 expression is modulated in response to heat and drought stresses and during plant recovery in Quercus suber.

Science.gov (United States)

Almeida, Tânia; Pinto, Glória; Correia, Barbara; Santos, Conceição; Gonçalves, Sónia

2013-12-01

Cork oak is an economically important forest species showing a great tolerance to high temperatures and shortage of water. However, the mechanisms underlying this plasticity are still poorly understood. Among the stress regulators, transcription factors (TFs) are especially important since they can control a wide range of stress-inducible genes, which make them powerful targets for genetic engineering of stress tolerance. Here we evaluated the influence of increasing temperatures (up to 55 °C) or drought (18% field capacity, FC) on the expression profile of an R2R3-MYB transcription factor of cork oak, the QsMYB1. QsMYB1 was previously identified as being preferentially expressed in cork tissues and as having an associated alternative splicing mechanism, which results in two different transcripts (QsMYB1.1 and QsMYB1.2). Expression analysis by reverse transcription quantitative PCR (RT-qPCR) revealed that increasing temperatures led to a gradual down-regulation of QsMYB1 transcripts with more effect on QsMYB1.1 abundance. On the other hand, under drought condition, expression of QsMYB1 variants, mainly the QsMYB1.2, was transiently up-regulated shortly after the stress imposition. Recovery from each stress has also resulted in a differential response by both QsMYB1 transcripts. Several physiological and biochemical parameters (plant water status, chlorophyll fluorescence, lipid peroxidation and proline content) were determined in order to monitor the plant performance under stress and recovery. In conclusion, this report provides the first evidence that QsMYB1 TF may have a putative function in the regulatory network of cork oak response to heat and drought stresses and during plant recovery. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

Attenuation of Vibrio fischeri quorum sensing using rationally designed polymers.

Science.gov (United States)

Piletska, Elena V; Stavroulakis, Georgios; Karim, Kal; Whitcombe, Michael J; Chianella, Iva; Sharma, Anant; Eboigbodin, Kevin E; Robinson, Gary K; Piletsky, Sergey A

2010-04-12

A first attempt to attenuate the quorum sensing (QS) of a marine heterotroph microorganism, Vibrio fischeri , using signal molecule-sequestering polymers (SSPs) is presented. A set of rationally designed polymers with affinity toward a signal molecule of V. fischeri , N-(beta-ketocaproyl)-l-homoserine lactone (3-oxo-C6-AHL) was produced. It is reported that computationally designed polymers could sequester a signal molecule of V. fischeri and prevent QS-controlled phenotypes (in this case, bioluminescence) from being up-regulated. It was proven that the attenuation of bioluminescence of V. fischeri was due to sequestration of the signal molecule by specific polymers and not due to the toxicity of polymer or nonspecific depletion of nutrients. The ability to disrupt the bacterial communication using easy to synthesize and chemically inert polymers could provide a new concept for the development of pharmaceuticals and susceptible device coatings such as catheters.

Functions and regulation of quorum-sensing in Agrobacterium tumefaciens

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Denis eFaure

2014-01-01

Full Text Available In Agrobacterium tumefaciens, horizontal transfer and vegetative replication of oncogenic Ti plasmids involve a cell-to-cell communication process called quorum-sensing (QS. The determinants of the QS-system belong to the LuxR/LuxI class. The LuxI-like protein TraI synthesizes N-acyl-homoserine lactone molecules which act as diffusible QS-signals. Beyond a threshold concentration, these molecules bind and activate the LuxR-like transcriptional regulator TraR, thereby initiating the QS-regulatory pathway. For the last twenty years, A. tumefaciens has stood as a prominent model in the understanding of the LuxR/LuxI type of QS systems. A number of studies also unveiled features which are unique to A. tumefaciens QS, some of them being directly related to the phytopathogenic lifestyle of the bacteria. In this review we will present the current knowledge of QS in A. tumefaciens at both the genetic and molecular levels. We will also describe how interactions with plant host modulate the QS pathway of A. tumefaciens, and discuss what could be the advantages for the agrobacteria to use such a tightly regulated QS-system to disseminate the Ti plasmids.

DMPD: Regulation of cytokine signaling by SOCS family molecules. [Dynamic Macrophage Pathway CSML Database

Lifescience Database Archive (English)

Full Text Available 14644140 Regulation of cytokine signaling by SOCS family molecules. Fujimoto M, Nak...a T. Trends Immunol. 2003 Dec;24(12):659-66. (.png) (.svg) (.html) (.csml) Show Regulation of cytokine signaling by SOCS family... molecules. PubmedID 14644140 Title Regulation of cytokine signaling by SOCS family molec

Calibrating accelerometer sensor on android phone with Accelerograph TDL 303 QS for earthquake online recorder

International Nuclear Information System (INIS)

Riantana, R.; Darsono, D.; Azimut, H.B.; Triyono, A.

2016-01-01

Calibration of the android censor was done by placing the device in a mounting at side of accelerograph TDL 303 QS that will be a means of comparison. Leveling of both devices was set same, so that the state of the device can be assumed same anyway. Then applied vibrations in order to have the maximum amplitude value of both censor, so it can be found equality of the coefficient of proportionality both of them. The results on both devices obtain the Peak Ground Acceleration (PGA) as follows, on the x axis (EW) android censor is obtained PGA -2.4478145 gal than at TDL 303 QS obtained PGA -2.5504 gal, the y-axis (NS) on the censor android obtained PGA 3.0066964 gal than at TDL 303 QS obtained PGA 3.2073 gal, the z-axis (UD) on the android censor obtained PGA -14.0702377 gal than at TDL 303 QS obtained PGA -13.2927 gal, A correction value for android accelerometer censor is ± 0.1 gal for the x-axis (EW), ± 0.2 gal for the y-axis (NS), and ± 0.7 gal for the z-axis (UD). (paper)

Stopping AI-2 chatter by means of an indigenous bacterium ( Acinetobacter sp. DKY-1): A new anti-biofouling strategy in an MBR for wastewater treatment.

Science.gov (United States)

Lee, Kibaek; Kim, Yea-Won; Lee, Seonki; Lee, Sang Hyun; Nahm, Chang Hyun; Kwon, Hyeokpil; Park, Pyung-Kyu; Choo, Kwang-Ho; Koyuncu, Ismail; Drews, Anja; Lee, Chung-Hak; Lee, Jung-Kee

2018-05-01

Bacterial quorum quenching (QQ) by means of degrading signaling molecules has been applied to anti-biofouling strategy in a membrane bioreactor (MBR) for wastewater treatment. However, the target signaling molecules have been limited to N-acyl homoserine lactones participating in intra-species quorum sensing. Here, an approach to disrupt autoinducer-2 (AI-2) signaling molecules participating in inter-species quorum sensing, was pursued as a next-generation anti-biofouling strategy in an MBR for wastewater treatment. We isolated an indigenous QQ bacterium ( Acinetobacter sp. DKY-1) that can attenuate the expression of quorum sensing (QS) response through inactivation of autoinducer-2 signaling molecule, 4,5-dihydroxy-2,3-pentanedione (DPD) among four kinds of autoinducer-2 QS bacteria. DKY-1 released AI-2 QQ compound(s), which was verified to be hydrophilic with a molecular weight biofouling. This new approach, combining molecular biology with wastewater engineering, could enlarge the range of QQ-MBR for anti-biofouling and energy savings in the field of wastewater treatment.

The role of quorum sensing signalling in EPS production and the assembly of a sludge community into aerobic granules.

Science.gov (United States)

Tan, Chuan Hao; Koh, Kai Shyang; Xie, Chao; Tay, Martin; Zhou, Yan; Williams, Rohan; Ng, Wun Jern; Rice, Scott A; Kjelleberg, Staffan

2014-06-01

Quorum sensing (QS) signalling has been extensively studied in single species populations. However, the ecological role of QS in complex, multi-species communities, particularly in the context of community assembly, has neither been experimentally explored nor theoretically addressed. Here, we performed a long-term bioreactor ecology study to address the links between QS, organization and composition of complex microbial communities. The conversion of floccular biomass to highly structured granules was found to be non-random, but strongly and positively correlated with N-acyl-homoserine-lactone (AHL)-mediated QS. Specific AHLs were elevated up to 100-fold and were strongly associated with the initiation of granulation. Similarly, the levels of particular AHLs decreased markedly during the granular disintegration phase. Metadata analysis indicated that granulation was accompanied by changes in extracellular polymeric substance (EPS) production and AHL add-back studies also resulted in increased EPS synthesis. In contrast to the commonly reported nanomolar to micromolar signal concentrations in pure culture laboratory systems, QS signalling in the granulation ecosystem occurred at picomolar to nanomolar concentrations of AHLs. Given that low concentrations of AHLs quantified in this study were sufficient to activate AHL bioreporters in situ in complex granular communities, AHL mediated QS may be a common feature in many natural and engineered ecosystems, where it coordinates community behaviour.

Meta-Analysis on Randomized Controlled Trials of Vaccines with QS-21 or ISCOMATRIX Adjuvant : Safety and Tolerability

NARCIS (Netherlands)

Bigaeva, Emilia; Doorn, Eva van; Liu, Heng; Hak, Eelko

2016-01-01

BACKGROUND AND OBJECTIVES: QS-21 shows in vitro hemolytic effect and causes side effects in vivo. New saponin adjuvant formulations with better toxicity profiles are needed. This study aims to evaluate the safety and tolerability of QS-21 and the improved saponin adjuvants (ISCOM, ISCOMATRIX and

Bacterial biofilms and quorum sensing: fidelity in bioremediation technology.

Science.gov (United States)

Mangwani, Neelam; Kumari, Supriya; Das, Surajit

Increased contamination of the environment with toxic pollutants has paved the way for efficient strategies which can be implemented for environmental restoration. The major problem with conventional methods used for cleaning of pollutants is inefficiency and high economic costs. Bioremediation is a growing technology having advanced potential of cleaning pollutants. Biofilm formed by various micro-organisms potentially provide a suitable microenvironment for efficient bioremediation processes. High cell density and stress resistance properties of the biofilm environment provide opportunities for efficient metabolism of number of hydrophobic and toxic compounds. Bacterial biofilm formation is often regulated by quorum sensing (QS) which is a population density-based cell-cell communication process via signaling molecules. Numerous signaling molecules such as acyl homoserine lactones, peptides, autoinducer-2, diffusion signaling factors, and α-hydroxyketones have been studied in bacteria. Genetic alteration of QS machinery can be useful to modulate vital characters valuable for environmental applications such as biofilm formation, biosurfactant production, exopolysaccharide synthesis, horizontal gene transfer, catabolic gene expression, motility, and chemotaxis. These qualities are imperative for bacteria during degradation or detoxification of any pollutant. QS signals can be used for the fabrication of engineered biofilms with enhanced degradation kinetics. This review discusses the connection between QS and biofilm formation by bacteria in relation to bioremediation technology.

Hypopigmentation Induced by Frequent Low-Fluence, Large-Spot-Size QS Nd:YAG Laser Treatments.

Science.gov (United States)

Wong, Yisheng; Lee, Siong See Joyce; Goh, Chee Leok

2015-12-01

The Q-switched 1064-nm neodymium-doped yttrium aluminum garnet (QS 1064-nm Nd:YAG) laser is increasingly used for nonablative skin rejuvenation or "laser toning" for melasma. Multiple and frequent low-fluence, large-spot-size treatments are used to achieve laser toning, and these treatments are associated with the development of macular hypopigmentation as a complication. We present a case series of three patients who developed guttate hypomelanotic macules on the face after receiving laser toning treatment with QS 1064-nm Nd:YAG.

Role of signaling lymphocytic activation molecule in T helper cell responses

Directory of Open Access Journals (Sweden)

Jan E. de Vries

1998-01-01

Full Text Available Signaling lymphocytic activation molecule (SLAM; CDw150 is a 70 kDa glycoprotein. Signaling lymphocytic activation molecule is constitutively expressed on memory T cells, CD56+ T cells, a subset of T cell receptor γδ+ cells, immature thymocytes and, at low levels, on a proportion of peripheral blood B cells. Signaling lymphocytic activation molecule is rapidly upregulated on all T and B cells after activation. Engagement of SLAM by F(ab’2 fragments of an anti-SLAM monoclonal antibody (mAb A12 enhances antigen-specific T cell proliferation. In addition, mAb A12 was directly mitogenic for T cell clones and activated T cells. T cell proliferation induced by mAb A12 is independent of interleukin (IL-2, IL-4, IL-12 and IL-15, but is cyclosporin A sensitive. Ligation of SLAM during antigen-specific T cell proliferation resulted in upregulation of interferon (IFN-γ production, even by allergen-specific T helper cell (Th 2 clones, whereas the levels of IL-4 and IL-5 production were only marginally affected. The mAb A12 was unable to induce IL-4 and IL-5 production by Th1 clones. Co-stimulation of skin-derived Der P1-specific Th2 cells from patients with atopic dermatitis via SLAM resulted in the generation of a population of IFN-γ-producing cells, thereby reverting their phenotype to a Th0 pattern. Signaling lymphocytic activation molecule is a high-affinity self ligand mediating homophilic cell interaction. In addition, soluble SLAM enhances both T and B cell proliferation. Collectively, these data indicate that SLAM molecules act both as receptors and ligands that are not only involved in T cell expansion but also drive the expanding T cells during immune responses into the Th0/Th1 pathway. This suggests that signaling through SLAM plays a role in directing Th0/Th1 development.

Global and Phylogenetic Distribution of Quorum Sensing Signals, Acyl Homoserine Lactones, in the Family of Vibrionaceae

DEFF Research Database (Denmark)

Rasmussen, Bastian Barker; Nielsen, Kristian Fog; Machado, Henrique

2014-01-01

Bacterial quorum sensing (QS) and the corresponding signals, acyl homoserine lactones (AHLs), were first described for a luminescent Vibrio species. Since then, detailed knowledge has been gained on the functional level of QS; however, the abundance of AHLs in the family of Vibrionaceae in the en......Bacterial quorum sensing (QS) and the corresponding signals, acyl homoserine lactones (AHLs), were first described for a luminescent Vibrio species. Since then, detailed knowledge has been gained on the functional level of QS; however, the abundance of AHLs in the family of Vibrionaceae...... violaceum reporter strains. Ethyl acetate extracts of the cultures were analysed by ultra-high performance liquid chromatography-high resolution mass spectrometry (MS) with automated tandem MS confirmation for AHLs. N-(3-hydroxy-hexanoyl) (OH-C6) and N-(3-hydroxy-decanoyl) (OH-C10) homoserine lactones were...

Identification and quantitation of signal molecule-dependent protein phosphorylation

KAUST Repository

Groen, Arnoud J.; Thomas, Ludivine; Lilley, Kathryn S.; Marondedze, Claudius

2013-01-01

in combination with phosphopeptide enrichment by titanium dioxide (TiO2) and their identification by MS is described. This workflow can be used to gain insights into the role of signalling molecules such as cyclic nucleotides on regulatory networks through

A density-dependent switch drives stochastic clustering and polarization of signaling molecules.

Directory of Open Access Journals (Sweden)

Alexandra Jilkine

2011-11-01

Full Text Available Positive feedback plays a key role in the ability of signaling molecules to form highly localized clusters in the membrane or cytosol of cells. Such clustering can occur in the absence of localizing mechanisms such as pre-existing spatial cues, diffusional barriers, or molecular cross-linking. What prevents positive feedback from amplifying inevitable biological noise when an un-clustered "off" state is desired? And, what limits the spread of clusters when an "on" state is desired? Here, we show that a minimal positive feedback circuit provides the general principle for both suppressing and amplifying noise: below a critical density of signaling molecules, clustering switches off; above this threshold, highly localized clusters are recurrently generated. Clustering occurs only in the stochastic regime, suggesting that finite sizes of molecular populations cannot be ignored in signal transduction networks. The emergence of a dominant cluster for finite numbers of molecules is partly a phenomenon of random sampling, analogous to the fixation or loss of neutral mutations in finite populations. We refer to our model as the "neutral drift polarity model." Regulating the density of signaling molecules provides a simple mechanism for a positive feedback circuit to robustly switch between clustered and un-clustered states. The intrinsic ability of positive feedback both to create and suppress clustering is a general mechanism that could operate within diverse biological networks to create dynamic spatial organization.

Detecting and characterizing N-acyl-homoserine lactone signal molecules by thin-layer chromatography

Science.gov (United States)

Shaw, Paul D.; Ping, Gao; Daly, Sean L.; Cha, Chung; Cronan, John E.; Rinehart, Kenneth L.; Farrand, Stephen K.

1997-01-01

Many Gram-negative bacteria regulate gene expression in response to their population size by sensing the level of acyl-homoserine lactone signal molecules which they produce and liberate to the environment. We have developed an assay for these signals that couples separation by thin-layer chromatography with detection using Agrobacterium tumefaciens harboring lacZ fused to a gene that is regulated by autoinduction. With the exception of N-butanoyl-l-homoserine lactone, the reporter detected acyl-homoserine lactones with 3-oxo-, 3-hydroxy-, and 3-unsubstituted side chains of all lengths tested. The intensity of the response was proportional to the amount of the signal molecule chromatographed. Each of the 3-oxo- and the 3-unsubstituted derivatives migrated with a unique mobility. Using the assay, we showed that some bacteria produce as many as five detectable signal molecules. Structures could be assigned tentatively on the basis of mobility and spot shape. The dominant species produced by Pseudomonas syringae pv. tabaci chromatographed with the properties of N-(3-oxohexanoyl)-l-homoserine lactone, a structure that was confirmed by mass spectrometry. An isolate of Pseudomonas fluorescens produced five detectable species, three of which had novel chromatographic properties. These were identified as the 3-hydroxy- forms of N-hexanoyl-, N-octanoyl-, and N-decanoyl-l-homoserine lactone. The assay can be used to screen cultures of bacteria for acyl-homoserine lactones, for quantifying the amounts of these molecules produced, and as an analytical and preparative aid in determining the structures of these signal molecules. PMID:9177164

Inhibition of Coenzyme Qs Accumulation in Engineered Escherichia coli by High Concentration of Farnesyl Diphosphate

OpenAIRE

Samoudi, Mojtaba; Omid Yeganeh, Negar; Shahbani Zahiri, Hossein; Shariati, Parvin; Hajhosseini, Reza

2015-01-01

Background: Coenzyme Q 10 (CoQ 10 ) is an isoprenoid component used widely in nutraceutical industries. Farnesyl diphosphate synthase (FPPS) is a responsible enzyme for biosynthesis of farnesyl diphosphate (FPP), a key precursor for CoQs production. This research involved investigating the effect of FPPS over-expression on CoQs production in engineered CoQ 10 -producing Escherichia coli (E. coli). Methods: Two CoQ 10 -producing strains, as referred to E. coli Ba and E. coli Br, were transform...

Boolean network model of the Pseudomonas aeruginosa quorum sensing circuits.

Science.gov (United States)

Dallidis, Stylianos E; Karafyllidis, Ioannis G

2014-09-01

To coordinate their behavior and virulence and to synchronize attacks against their hosts, bacteria communicate by continuously producing signaling molecules (called autoinducers) and continuously monitoring the concentration of these molecules. This communication is controlled by biological circuits called quorum sensing (QS) circuits. Recently QS circuits and have been recognized as an alternative target for controlling bacterial virulence and infections without the use of antibiotics. Pseudomonas aeruginosa is a Gram-negative bacterium that infects insects, plants, animals and humans and can cause acute infections. This bacterium has three interconnected QS circuits that form a very complex and versatile QS system, the operation of which is still under investigation. Here we use Boolean networks to model the complete QS system of Pseudomonas aeruginosa and we simulate and analyze its operation in both synchronous and asynchronous modes. The state space of the QS system is constructed and it turned out to be very large, hierarchical, modular and scale-free. Furthermore, we developed a simulation tool that can simulate gene knock-outs and study their effect on the regulons controlled by the three QS circuits. The model and tools we developed will give to life scientists a deeper insight to this complex QS system.

The effect of CD4 receptor downregulation and its downstream signaling molecules on HIV-1 latency

International Nuclear Information System (INIS)

Kim, Kyung-Chang; Kim, Hyeon Guk; Roh, Tae-Young; Park, Jihwan; Jung, Kyung-Min; Lee, Joo-Shil; Choi, Sang-Yun; Kim, Sung Soon; Choi, Byeong-Sun

2011-01-01

Research highlights: → CD4 receptors were downregulated on the surface of HIV-1 latently infected cells. → CD4 downstream signaling molecules were suppressed in HIV-1 latently infected cells. → HIV-1 progeny can be reactivated by induction of T-cell activation signal molecules. → H3K4me3 and H3K9ac were highly enriched in CD4 downstream signaling molecules. → HIV-1 latency can be maintained by the reduction of downstream signaling molecules. -- Abstract: HIV-1 can establish a latent infection in memory CD4 + T cells to evade the host immune response. CD4 molecules can act not only as the HIV-1 receptor for entry but also as the trigger in an intracellular signaling cascade for T-cell activation and proliferation via protein tyrosine kinases. Novel chronic HIV-1-infected A3.01-derived (NCHA) cells were used to examine the involvement of CD4 downstream signaling in HIV-1 latency. CD4 receptors in NCHA cells were dramatically downregulated on its surface but were slightly decreased in whole-cell lysates. The expression levels of CD4 downstream signaling molecules, including P56 Lck , ZAP-70, LAT, and c-Jun, were sharply decreased in NCHA cells. The lowered histone modifications of H3K4me3 and H3K9ac correlated with the downregulation of P56 Lck , ZAP-70, and LAT in NCHA cells. AP-1 binding activity was also reduced in NCHA cells. LAT and c-Jun suppressed in NCHA cells were highly induced after PMA treatment. In epigenetic analysis, other signal transduction molecules which are associated with active and/or latent HIV-1 infection showed normal states in HIV-1 latently infected cells compared to A3.01 cells. In conclusion, we demonstrated that the HIV-1 latent state is sustained by the reduction of downstream signaling molecules via the downregulation of CD4 and the attenuated activity of transcription factor as AP-1. The HIV-1 latency model via T-cell deactivation may provide some clues for the development of the new antireservoir therapy.

The effect of CD4 receptor downregulation and its downstream signaling molecules on HIV-1 latency

Energy Technology Data Exchange (ETDEWEB)

Kim, Kyung-Chang [National Institute of Health, Chungbuk (Korea, Republic of); School of Life Science and Biotechnology, Korea University, Seoul (Korea, Republic of); Kim, Hyeon Guk [National Institute of Health, Chungbuk (Korea, Republic of); Roh, Tae-Young [Division of Molecular and Life Science, Pohang University of Science and Technology, Pohang, Gyeongbuk (Korea, Republic of); Division of Integrative Biosciences and Biotechnology, Pohang University of Science and Technology, Pohang, Gyeongbuk (Korea, Republic of); Park, Jihwan [Division of Molecular and Life Science, Pohang University of Science and Technology, Pohang, Gyeongbuk (Korea, Republic of); Jung, Kyung-Min; Lee, Joo-Shil [National Institute of Health, Chungbuk (Korea, Republic of); Choi, Sang-Yun [School of Life Science and Biotechnology, Korea University, Seoul (Korea, Republic of); Kim, Sung Soon [National Institute of Health, Chungbuk (Korea, Republic of); Choi, Byeong-Sun, E-mail: byeongsun@korea.kr [National Institute of Health, Chungbuk (Korea, Republic of)

2011-01-14

Research highlights: {yields} CD4 receptors were downregulated on the surface of HIV-1 latently infected cells. {yields} CD4 downstream signaling molecules were suppressed in HIV-1 latently infected cells. {yields} HIV-1 progeny can be reactivated by induction of T-cell activation signal molecules. {yields} H3K4me3 and H3K9ac were highly enriched in CD4 downstream signaling molecules. {yields} HIV-1 latency can be maintained by the reduction of downstream signaling molecules. -- Abstract: HIV-1 can establish a latent infection in memory CD4 + T cells to evade the host immune response. CD4 molecules can act not only as the HIV-1 receptor for entry but also as the trigger in an intracellular signaling cascade for T-cell activation and proliferation via protein tyrosine kinases. Novel chronic HIV-1-infected A3.01-derived (NCHA) cells were used to examine the involvement of CD4 downstream signaling in HIV-1 latency. CD4 receptors in NCHA cells were dramatically downregulated on its surface but were slightly decreased in whole-cell lysates. The expression levels of CD4 downstream signaling molecules, including P56{sup Lck}, ZAP-70, LAT, and c-Jun, were sharply decreased in NCHA cells. The lowered histone modifications of H3K4me3 and H3K9ac correlated with the downregulation of P56{sup Lck}, ZAP-70, and LAT in NCHA cells. AP-1 binding activity was also reduced in NCHA cells. LAT and c-Jun suppressed in NCHA cells were highly induced after PMA treatment. In epigenetic analysis, other signal transduction molecules which are associated with active and/or latent HIV-1 infection showed normal states in HIV-1 latently infected cells compared to A3.01 cells. In conclusion, we demonstrated that the HIV-1 latent state is sustained by the reduction of downstream signaling molecules via the downregulation of CD4 and the attenuated activity of transcription factor as AP-1. The HIV-1 latency model via T-cell deactivation may provide some clues for the development of the new

Losing the Warning Signal: Drought Compromises the Cross-Talk of Signaling Molecules in Quercus ilex Exposed to Ozone

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Lorenzo Cotrozzi

2017-06-01

Full Text Available Understanding the interactions between drought and acute ozone (O3 stress in terms of signaling molecules and cell death would improve the predictions of plant responses to climate change. The aim was to investigate whether drought stress influences the responses of plants to acute episodes of O3 exposure. In this study, the behavior of 84 Mediterranean evergreen Quercus ilex plants was evaluated in terms of cross-talk responses among signaling molecules. Half of the sample was subjected to drought (20% of the effective daily evapotranspiration, for 15 days and was later exposed to an acute O3 exposure (200 nL L-1 for 5 h. First, our results indicate that in well-water conditions, O3 induced a signaling pathway specific to O3-sensitive behavior. Second, different trends and consequently different roles of phytohormones and signaling molecules (ethylene, ET; abscisic acid, ABA; salycilic acid, SA and jasmonic acid, JA were observed in relation to water stress and O3. A spatial and functional correlation between these signaling molecules was observed in modulating O3-induced responses in well-watered plants. In contrast, in drought-stressed plants, these compounds were not involved either in O3-induced signaling mechanisms or in leaf senescence (a response observed in water-stressed plants before the O3-exposure. Third, these differences were ascribable to the fact that in drought conditions, most defense processes induced by O3 were compromised and/or altered. Our results highlight how Q. ilex plants suffering from water deprivation respond differently to an acute O3 episode compared to well-watered plants, and suggest new effect to be considered in plant responses to environmental changes. This poses the serious question as to whether or not multiple high-magnitude O3 events (as predicted can change these cross-talk responses, thus opening it up possible further investigations.

Pseudoscalar-photon mixing and the large scale alignment of QsO ...

Indian Academy of Sciences (India)

physics pp. 679-682. Pseudoscalar-photon mixing and the large scale alignment of QsO optical polarizations. PANKAJ JAIN, sUKANTA PANDA and s sARALA. Physics Department, Indian Institute of Technology, Kanpur 208 016, India. Abstract. We review the observation of large scale alignment of QSO optical polariza-.

Systemic Synthesis Questions [SSynQs] as Tools to Help Students to Build Their Cognitive Structures in a Systemic Manner

Science.gov (United States)

Hrin, Tamara N.; Fahmy, Ameen F. M.; Segedinac, Mirjana D.; Milenković, Dušica D.

2016-08-01

Many studies dedicated to the teaching and learning of organic chemistry courses have emphasized that high school students have shown significant difficulties in mastering the concepts of this discipline. Therefore, the aim of our study was to help students to overcome these difficulties by applying systemic synthesis questions, [SSynQs], as the instructional method in our intervention. This work shows that students from the group exposed to the new teaching method achieved higher scores on final testing than students from the control group, who were taught by the traditional method, when students' achievements in conventional, linear questions [LQs] and in [SSynQs] were studied. These results were followed by observation of lower levels of mental effort by students from the intervention group, and higher levels of mental effort in the control group, invested during solving both types of questions. This correlation between achievement and mental effort resulted in high instructional efficiency for the applied method in the intervention group, [SSynQs], and low instructional efficiency for the traditional teaching and learning method applied in the control group. A systemic triangular relation between achievement, mental effort, and instructional efficiency, established by each group and gender, emphasized that the application of [SSynQs] was more suited to female students than for male students because of [SSynQs] characteristics as teaching and learning tools and because of learning style and ability differences between genders.

Recent progresses on AI-2 bacterial quorum sensing inhibitors.

Science.gov (United States)

Zhu, Peng; Li, Minyong

2012-01-01

Quorum sensing (QS) is a communication procedure that predominates gene expression in response to cell density and fluctuations in the neighboring environment as a result of discerning molecules termed autoinducers (AIs). It has been embroiled that QS can govern bacterial behaviors such as the secretion of virulence factors, biofilm formation, bioluminescence production, conjugation, sporulation and swarming motility. Autoinducer 2 (AI-2), a QS signaling molecule brought up to be involved in interspecies communication, exists in both gram-negative and -positive bacteria. Therefore, novel approaches to interrupt AI-2 quorum sensing are being recognized as next generation antimicrobials. In the present review article, we summarized recent progresses on AI-2 bacterial quorum sensing inhibitors and discussed their potential as the antibacterial agents.

Carbon Monoxide: An Essential Signalling Molecule

Science.gov (United States)

Mann, Brian E.

Carbon monoxide (CO), like nitric oxide (NO), is an essential signalling molecule in humans. It is active in the cardiovascular system as a vasodilator. In addition, CO possesses anti-inflammatory, anti-apoptotic and anti-proliferative properties and protects tissues from hypoxia and reperfusion injury. Some of its applications in animal models include suppression of organ graft rejection and safeguarding the heart during reperfusion after cardiopulmonary bypass surgery. CO also suppresses arteriosclerotic lesions following angioplasty, reverses established pulmonary hypertension and mitigates the development of post-operative ileus in the murine small intestine and the development of cerebral malaria in mice as well as graft-induced intimal hyperplasia in pigs. There have been several clinical trials using air-CO mixtures for the treatment of lung-, heart-, kidney- and abdominal-related diseases. This review examines the research involving the development of classes of compounds (with particular emphasis on metal carbonyls) that release CO, which could be used in clinically relevant conditions. The review is drawn not only from published papers in the chemical literature but also from the extensive biological literature and patents on CO-releasing molecules (CO-RMs).

Quorum Sensing Signaling and Quenching in the Multidrug-Resistant Pathogen Stenotrophomonas maltophilia

Directory of Open Access Journals (Sweden)

Pol Huedo

2018-04-01

Full Text Available Stenotrophomonas maltophilia is an opportunistic Gram-negative pathogen with increasing incidence in clinical settings. The most critical aspect of S. maltophilia is its frequent resistance to a majority of the antibiotics of clinical use. Quorum Sensing (QS systems coordinate bacterial populations and act as major regulatory mechanisms of pathogenesis in both pure cultures and poly-microbial communities. Disruption of QS systems, a phenomenon known as Quorum Quenching (QQ, represents a new promising paradigm for the design of novel antimicrobial strategies. In this context, we review the main advances in the field of QS in S. maltophilia by paying special attention to Diffusible Signal Factor (DSF signaling, Acyl Homoserine Lactone (AHL responses and the controversial Ax21 system. Advances in the DSF system include regulatory aspects of DSF synthesis and perception by both rpf-1 and rpf-2 variant systems, as well as their reciprocal communication. Interaction via DSF of S. maltophilia with unrelated organisms including bacteria, yeast and plants is also considered. Finally, an overview of the different QQ mechanisms involving S. maltophilia as quencher and as object of quenching is presented, revealing the potential of this species for use in QQ applications. This review provides a comprehensive snapshot of the interconnected QS network that S. maltophilia uses to sense and respond to its surrounding biotic or abiotic environment. Understanding such cooperative and competitive communication mechanisms is essential for the design of effective anti QS strategies.

Biosensors for the Detection and Quantification of AI-2 Class Quorum-Sensing Compounds.

Science.gov (United States)

Rajamani, Sathish; Sayre, Richard

2018-01-01

Intercellular small-molecular-weight signaling molecules modulate a variety of biological functions in bacteria. One of the more complex behaviors mediated by intercellular signaling molecules is the suite of activities regulated by quorum-sensing molecules. These molecules mediate a variety of population-dependent responses including the expression of genes that regulate bioluminescence, type III secretion, siderophore production, colony morphology, biofilm formation, and metalloprotease production. Given their central role in regulating these responses, the detection and quantification of QS molecules have important practical implications. Until recently, the detection of QS molecules from Gram-negative bacteria has relied primarily on bacterial reporter systems. These bioassays though immensely useful are subject to interference by compounds that affect bacterial growth and metabolism. In addition, the reporter response is highly dependent on culture age and cell population density. To overcome such limitations, we developed an in vitro protein-based assay system for the rapid detection and quantification of the furanosyl borate diester (BAI-2) subclass of autoinducer-2 (AI-2) QS molecules. The biosensor is based on the interaction of BAI-2 with the Vibrio harveyi QS receptor LuxP. Conformation changes associated with BAI-2 binding to the LuxP receptor change the orientation of cyan and yellow variants of GFP (CFP and YFP) fused to the N- and C-termini, respectively, of the LuxP receptor. LuxP-BAI2 binding induces changes in fluorescence resonance energy transfer (FRET) between CFP and YFP, whose magnitude of change is ligand concentration dependent. Ligand-insensitive LuxP mutant FRET protein sensors were also developed for use as control biosensors. The FRET-based BAI-2 biosensor responds selectively to both synthetic and biologically derived BAI-2 compounds. This report describes the use of the LuxP-FRET biosensor for the detection and quantification of BAI-2.

FRET-based biosensors for the detection and quantification of AI-2 class of quorum sensing compounds.

Science.gov (United States)

Rajamani, Sathish; Sayre, Richard

2011-01-01

Intercellular small molecular weight signaling molecules modulate a variety of biological functions in bacteria. One of the more complex behaviors mediated by intercellular signaling molecules is the suite of activities regulated by quorum sensing molecules. These molecules mediate a variety of population-dependent responses, including the expression of genes that regulate bioluminescence, type III secretion, siderophore production, colony morphology, biofilm formation, and metalloprotease production. Given their central role in regulating these responses, the detection and quantification of QS molecules has important practical implications. Until recently, the detection of QS molecules from Gram-negative bacteria has relied primarily on bacterial reporter systems. These bioassays though immensely useful are subject to interference by compounds that affect bacterial growth and metabolism. In addition, the reporter response is highly dependent on culture age and cell population density. To overcome such limitations, we developed an in vitro protein-based assay system for the rapid detection and quantification of the furanosyl borate diester (BAI-2) subclass of autoinducer-2 (AI-2) QS molecules. The biosensor is based on the interaction of BAI-2 with the Vibrio harveyi QS receptor LuxP. Conformation changes associated with BAI-2 binding to the LuxP receptor change the orientation of cyan and yellow variants of GFP (CFP and YFP) fused the N- and C-termini, respectively, of the LuxP receptor. LuxP-BAI2 binding induces changes in fluorescence resonance energy transfer (FRET) between CFP and YFP, whose magnitude of change is ligand concentration dependent. A set of ligand-insensitive LuxP-mutant FRET protein sensor was also developed for use as control biosensors. The FRET-based BAI-2 biosensor responds selectively to both synthetic and biologically derived BAI-2compounds. This report describes the use of the LuxP-FRET biosensor for the detection and quantification of

Intercellular communication in Helicobacter pylori: luxS is essential for the production of an extracellular signaling molecule.

Science.gov (United States)

Forsyth, M H; Cover, T L

2000-06-01

Individual bacteria of numerous species can communicate and coordinate their actions via the production, release, and detection of extracellular signaling molecules. In this study, we used the Vibrio harveyi luminescence bioassay to determine whether Helicobacter pylori produces such a factor. Cell-free conditioned media from H. pylori strains 60190 and 26695 each induced >100-fold-greater luminescence in V. harveyi than did sterile culture medium. The H. pylori signaling molecule had a molecular mass of 100-fold-greater luminescence in the V. harveyi bioassay than did conditioned medium from either mutant strain. Production of the signaling molecule was restored in an H. pylori luxS null mutant strain by complementation with a single intact copy of luxS placed in a heterologous site on the chromosome. In addition, Escherichia coli DH5alpha produced autoinducer activity following the introduction of an intact copy of luxS from H. pylori. Production of the signaling molecule by H. pylori was growth phase dependent, with maximal production occurring in the mid-exponential phase of growth. Transcription of H. pylori vacA also was growth phase dependent, but this phenomenon was not dependent on luxS activity. These data indicate that H. pylori produces an extracellular signaling molecule related to AI-2 from V. harveyi. We speculate that this signaling molecule may play a role in regulating H. pylori gene expression.

Raw cow’s milk relatively inhibits quorum sensing activity of Cromobacterium violaceum in comparison to raw she-camel’s milk

Directory of Open Access Journals (Sweden)

A.A. Moawad

2011-10-01

Full Text Available Milk from different animal species has variable levels of antimicrobial factors against some of spoilage bacteria. For example, they are significantly present in higher concentration in she-camel’s milk than in cattle or buffalo and they are more heat-resistant than their counterparts in cattle and buffalo. Spoilage bacteria are known to communicate with each other by release of signaling molecules, a phenomenon described as quorum sensing (QS. Some food matrices inhibit these signaling compounds. In this study we screened QS inhibitory activities in raw milk of cattle and camel. Ten samples each of fresh raw cow’s milk and she-camel’s milk from apparently healthy animals were screened using the bacterial model Cromobacterium violaceum. The tested cow’s raw milk samples were able to inhibit the production of QS signalling molecules acyl-homoserine lactones (AHLs produced by C. violaceum. However, she-camel’s milk samples were less effective in inhibiting such AHLs. Thus, one of the factors which influence the inhibitory activity could be derived from variation in milk chemical composition, especially in the percentage of fat which is significantly higher in tested cow’s milk samples (2.22±0.12 than in tested she-camel’s milk samples (1.44±0.35. Natural inhibition of QS signaling by cow’s milk may offer a unique means to control foodborne pathogens and reduce microbial spoilage.

Beneficial effects of bacteria-plant communication based on quorum sensing molecules of the N-acyl homoserine lactone group.

Science.gov (United States)

Schikora, Adam; Schenk, Sebastian T; Hartmann, Anton

2016-04-01

Bacterial quorum sensing (QS) mechanisms play a crucial role in the proper performance and ecological fitness of bacterial populations. Many key physiological processes are regulated in a QS-dependent manner by auto-inducers, like the N-acyl homoserine lactones (AHLs) in numerous Gram-negative bacteria. In addition, also the interaction between bacteria and eukaryotic hosts can be regulated by AHLs. Those mechanisms gained much attention, because of the positive effects of different AHL molecules on plants. This positive impact ranges from growth promotion to induced resistance and is quite contrasting to the rather negative effects observed in the interactions between bacterial AHL molecules and animals. Only very recently, we began to understand the molecular mechanisms underpinning plant responses to AHL molecules. In this review, we gathered the latest information in this research field. The first part gives an overview of the bacterial aspects of quorum sensing. Later we focus on the impact of AHLs on plant growth and AHL-priming, as one of the most understood phenomena in respect to the inter-kingdom interactions based on AHL-quorum sensing molecules. Finally, we discuss the potential benefits of the understanding of bacteria-plant interaction for the future agricultural applications.

Signaling mechanisms of neurite outgrowth induced by the cell adhesion molecules NCAM and N-cadherin

DEFF Research Database (Denmark)

Hansen, S M; Berezin, V; Bock, E

2008-01-01

Formation of appropriate neural circuits depends on a complex interplay between extracellular guiding cues and intracellular signaling events that result in alterations of cytoskeletal dynamics and a neurite growth response. Surface-expressed cell adhesion molecules (CAMs) interact with the surro......Formation of appropriate neural circuits depends on a complex interplay between extracellular guiding cues and intracellular signaling events that result in alterations of cytoskeletal dynamics and a neurite growth response. Surface-expressed cell adhesion molecules (CAMs) interact...... extracellular guidance cues to intracellular events and thereby regulating neurite outgrowth. In this review, we focus on two CAMs, the neural cell adhesion molecule (NCAM) and N-cadherin, and their ability to mediate signaling associated with a neurite outgrowth response. In particular, we will focus on direct...

A chemical biology approach to interrogate quorum-sensing regulated behaviors at the molecular and cellular level.

Science.gov (United States)

Lowery, Colin A; Matamouros, Susana; Niessen, Sherry; Zhu, Jie; Scolnick, Jonathan; Lively, Jenny M; Cravatt, Benjamin F; Miller, Samuel I; Kaufmann, Gunnar F; Janda, Kim D

2013-07-25

Small molecule probes have been used extensively to explore biologic systems and elucidate cellular signaling pathways. In this study, we use an inhibitor of bacterial communication to monitor changes in the proteome of Salmonella enterica serovar Typhimurium with the aim of discovering unrecognized processes regulated by AI-2-based quorum-sensing (QS), a mechanism of bacterial intercellular communication that allows for the coordination of gene expression in a cell density-dependent manner. In S. typhimurium, this system regulates the uptake and catabolism of intercellular signals and has been implicated in pathogenesis, including the invasion of host epithelial cells. We demonstrate that our QS antagonist is capable of selectively inhibiting the expression of known QS-regulated proteins in S. typhimurium, thus attesting that QS inhibitors may be used to confirm proposed and elucidate previously unidentified QS pathways without relying on genetic manipulation. Copyright © 2013 Elsevier Ltd. All rights reserved.

Pseudomonas aeruginosa forms Biofilms in Acute InfectionIndependent of Cell-to-Cell Signaling

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Schaber, J. Andy; Triffo, W.J.; Suh, Sang J.; Oliver, Jeffrey W.; Hastert, Mary C.; Griswold, John A.; Auer, Manfred; Hamood, Abdul N.; Rumbaugh, Kendra P.

2006-09-20

Biofilms are bacterial communities residing within a polysaccharide matrix that are associated with persistence and antibiotic resistance in chronic infections. We show that the opportunistic pathogen Pseudomonas aeruginosa forms biofilms within 8 hours of infection in thermally-injured mice, demonstrating that biofilms contribute to bacterial colonization in acute infections. P. aeruginosa biofilms were visualized within burned tissue surrounding blood vessels and adipose cells. Although quorum sensing (QS), a bacterial signaling mechanism, coordinates differentiation of biofilms in vitro, wild type and QS-deficient P. aeruginosa formed similar biofilms in vivo. Our findings demonstrate that P. aeruginosa forms biofilms on specific host tissues independent of QS.

[Enzymes for disrupting bacterial communication, an alternative to antibiotics?

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Rémy, B; Plener, L; Elias, M; Daudé, D; Chabrière, E

2016-11-01

Quorum sensing (QS) is used by bacteria to communicate and synchronize their actions according to the cell density. In this way, they produce and secrete in the surrounding environment small molecules dubbed autoinducers (AIs) that regulate the expression of certain genes. The phenotypic traits regulated by QS are diverse and include pathogenicity, biofilm formation or resistance to anti-microbial treatments. The strategy, aiming at disrupting QS, known as quorum quenching (QQ), has emerged to counteract bacterial virulence and involves QS-inhibitors (QSI) or QQ-enzymes degrading AIs. Differently from antibiotics, QQ aims at blocking cell signaling and does not alter bacterial survival. This considerably decreases the selection pressure as compared to bactericide treatments and may reduce the occurrence of resistance mechanisms. QQ-enzymes are particularly appealing as they may disrupt molecular QS-signal without entering the cell and in a catalytic way. This review covers several aspects of QQ-based medical applications and the potential subsequent emergence of resistance is discussed. Copyright © 2016 Académie Nationale de Pharmacie. All rights reserved.

Discovery of novel small molecule activators of β-catenin signaling.

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Folkert Verkaar

Full Text Available Wnt/β-catenin signaling plays a major role in embryonic development and adult stem cell maintenance. Reduced activation of the Wnt/β-catenin pathway underlies neurodegenerative disorders and aberrations in bone formation. Screening of a small molecule compound library with a β-galactosidase fragment complementation assay measuring β-catenin nuclear entry revealed bona fide activators of β-catenin signaling. The compounds stabilized cytoplasmic β-catenin and activated β-catenin-dependent reporter gene activity. Although the mechanism through which the compounds activate β-catenin signaling has yet to be determined, several key regulators of Wnt/β-catenin signaling, including glycogen synthase kinase 3 and Frizzled receptors, were excluded as the molecular target. The compounds displayed remarkable selectivity, as they only induced β-catenin signaling in a human osteosarcoma U2OS cell line and not in a variety of other cell lines examined. Our data indicate that differences in cellular Wnt/β-catenin signaling machinery can be exploited to identify cell type-specific activators of Wnt/β-catenin signaling.

Cross-kingdom signalling: exploitation of bacterial quorum sensing molecules by the green seaweed Ulva.

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Joint, Ian; Tait, Karen; Wheeler, Glen

2007-07-29

The green seaweed Ulva has been shown to detect signal molecules produced by bacteria. Biofilms that release N-acylhomoserine lactones (AHLs) attract zoospores--the motile reproductive stages of Ulva. The evidence for AHL involvement is based on several independent lines of evidence, including the observation that zoospores are attracted to wild-type bacteria that produce AHLs but are not attracted to mutants that do not produce signal molecules. Synthetic AHL also attracts zoospores and the attraction is lost in the presence of autoinducer inactivation (AiiA) protein. The mechanism of attraction is not chemotactic but involves chemokinesis. When zoospores detect AHLs, the swimming rate is reduced and this results in accumulation of cells at the source of the AHL. It has been demonstrated that the detection of AHLs results in calcium influx into the zoospore. This is the first example of a calcium signalling event in a eukaryote in response to bacterial quorum sensing molecules. The role of AHLs in the ecology of Ulva is discussed. It is probable that AHLs act as cues for the settlement of zoospores, rather than being directly involved as a signalling mechanism.

Crosstalk Regulates the Capacity for Robust Collective Decision Making in Heterogeneous Microbial Communities

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Yusufaly, Tahir; Boedicker, James

Microbial communities frequently communicate via quorum sensing (QS), where cells produce, secrete, and respond to a threshold level of an autoinducer (AI) molecule, thereby modulating density-dependent gene expression. However, the biology of QS remains incompletely understood in heterogeneous communities, where crosstalk between distinct QS systems leads to novel effects. Such knowledge is necessary both for understanding signaling in real microbial communities, and for the rational design of synthetic communities with designer properties. As a step towards this goal, we investigate the effects of crosstalk between Gram-negative bacteria communicating via LuxI/LuxR-type QS systems, with acyl-homoserine lactone (AHL) AI molecules. After mapping QS in a heterogeneous community onto an artificial neural network model, we systematically analyze how heterogeneity regulates the community's capability for stable yet flexible decision making. We find that there are preferred distributions of interactions which provide optimal tradeoffs between capacity, or the number of different decisions a population can make, and robustness, or the tolerance of the community to disturbances. We compare our results to inferences made from experimental data, and critically discuss implications for the biological significance of crosstalk.

Wnt/beta-Catenin Signaling and Small Molecule Inhibitors

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Voronkov, Andrey; Krauss, Stefan

2012-01-01

Wnt/β-catenin signaling is a branch of a functional network that dates back to the first metazoans and it is involved in a broad range of biological systems including stem cells, embryonic development and adult organs. Deregulation of components involved in Wnt/β-catenin signaling has been implicated in a wide spectrum of diseases including a number of cancers and degenerative diseases. The key mediator of Wnt signaling, β-catenin, serves several cellular functions. It functions in a dynamic mode at multiple cellular locations, including the plasma membrane, where β-catenin contributes to the stabilization of intercellular adhesive complexes, the cytoplasm where β-catenin levels are regulated and the nucleus where β-catenin is involved in transcriptional regulation and chromatin interactions. Central effectors of β-catenin levels are a family of cysteine-rich secreted glycoproteins, known as Wnt morphogens. Through the LRP5/6-Frizzled receptor complex, Wnts regulate the location and activity of the destruction complex and consequently intracellular β- catenin levels. However, β-catenin levels and their effects on transcriptional programs are also influenced by multiple other factors including hypoxia, inflammation, hepatocyte growth factor-mediated signaling, and the cell adhesion molecule E-cadherin. The broad implications of Wnt/β-catenin signaling in development, in the adult body and in disease render the pathway a prime target for pharmacological research and development. The intricate regulation of β-catenin at its various locations provides alternative points for therapeutic interventions. PMID:23016862

Chaos Q-S synchronization between Rossler system and the new unified chaotic system

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Yan Zhenya

2005-01-01

In this Letter, we investigate the Q-S synchronization between two different chaotic systems: the Rossler system and the new unified Lorenz-Chen-Lu system based on the backstepping design method and Lyapunov stability theory. Moreover numerical simulations are used to verify the effectiveness of the proposed controller

All-optical signal processing at 10 GHz using a photonic crystal molecule

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Combrié, Sylvain; Lehoucq, Gaëlle; Junay, Alexandra; De Rossi, Alfredo, E-mail: alfredo.derossi@thalesgroup.com [Thales Research and Technology, 1 Avenue A. Fresnel, 91767 Palaiseau (France); Malaguti, Stefania; Bellanca, Gaetano; Trillo, Stefano [Department of Engineering, Università di Ferrara, v. Saragat 1, 44122 Ferrara (Italy); Ménager, Loic [Thales Systèmes Aeroportés, 2 Av. Gay Lussac, 78851 Elancourt (France); Peter Reithmaier, Johann [Institute of Nanostructure Technologies and Analytics, CINSaT, University of Kassel, Heinrich-Plett-Str. 40, 34132 Kassel (Germany)

2013-11-04

We report on 10 GHz operation of an all-optical gate based on an Indium Phosphide Photonic Crystal Molecule. Wavelength conversion and all-optical mixing of microwave signals are demonstrated using the 2 mW output of a mode locked diode laser. The spectral separation of the optical pump and signal is crucial in suppressing optical cross-talk.

Small Molecules Affect Human Dental Pulp Stem Cell Properties Via Multiple Signaling Pathways

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Al-Habib, Mey; Yu, Zongdong

2013-01-01

One fundamental issue regarding stem cells for regenerative medicine is the maintenance of stem cell stemness. The purpose of the study was to test whether small molecules can enhance stem cell properties of mesenchymal stem cells (MSCs) derived from human dental pulp (hDPSCs), which have potential for multiple clinical applications. We identified the effects of small molecules (Pluripotin (SC1), 6-bromoindirubin-3-oxime and rapamycin) on the maintenance of hDPSC properties in vitro and the mechanisms involved in exerting the effects. Primary cultures of hDPSCs were exposed to optimal concentrations of these small molecules. Treated hDPSCs were analyzed for their proliferation, the expression levels of pluripotent and MSC markers, differentiation capacities, and intracellular signaling activations. We found that small molecule treatments decreased cell proliferation and increased the expression of STRO-1, NANOG, OCT4, and SOX2, while diminishing cell differentiation into odonto/osteogenic, adipogenic, and neurogenic lineages in vitro. These effects involved Ras-GAP-, ERK1/2-, and mTOR-signaling pathways, which may preserve the cell self-renewal capacity, while suppressing differentiation. We conclude that small molecules appear to enhance the immature state of hDPSCs in culture, which may be used as a strategy for adult stem cell maintenance and extend their capacity for regenerative applications. PMID:23573877

Small Molecules Inspired by the Natural Product Withanolides as Potent Inhibitors of Wnt Signaling.

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Sheremet, Michael; Kapoor, Shobhna; Schröder, Peter; Kumar, Kamal; Ziegler, Slava; Waldmann, Herbert

2017-09-19

Wnt signaling is a fundamental pathway that drives embryonic development and is essential for stem cell maintenance and tissue homeostasis. Dysregulation of Wnt signaling is linked to various diseases, and a constitutively active Wnt pathway drives tumorigenesis. Thus, disruption of the Wnt response is deemed a promising strategy for cancer drug discovery. However, only few clinical drug candidates that target Wnt signaling are available so far, and new small-molecule modulators of Wnt-related processes are in high demand. Here we describe the synthesis of small molecules inspired by withanolide natural products by using a pregnenolone-derived β-lactone as the key intermediate that was transformed into a δ-lactone appended to the D-ring of the steroidal scaffold. This natural-product-inspired compound library contained potent inhibitors of Wnt signaling that act upstream of the destruction complex to stabilize Axin in a tankyrase-independent manner. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Role and regulation of the orphan AphA protein of quorum sensing in pathogenic Vibrios.

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Lu, Renfei; Osei-Adjei, George; Huang, Xinxiang; Zhang, Yiquan

2018-03-01

Quorum sensing (QS), a cell-to-cell communication process, is widely distributed in the bacterial kingdom. Bacteria use QS to control gene expression in response to cell density by detecting the signal molecules called autoinducers. AphA protein is the master QS regulator of vibrios operating at low cell density. It regulates the expression of a variety of genes, especially those encoding virulence factors, flagella/motility and biofilm formation. The role and regulation of AphA in vibrios, especially in human pathogenic vibrios, are summarized in this review. Clarification of the roles of AphA will help us to understand the pathogenesis of vibrios.

The response of type 2 quorum sensing in Klebsiella pneumoniae to a fluctuating culture environment.

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Zhu, Hu; Liu, Hui-Jun; Ning, Shou-Jiao; Gao, Yu-Li

2012-04-01

Bacterial cells communicate with one another using chemical signaling molecules. This phenomenon is termed quorum sensing (QS). QS in Klebsiella pneumoniae is mediated by the synthesis of interspecies autoinducer 2 (AI-2), a furanosyl borate diester molecule. The response of Type 2 QS to environmental cues such as carbon sources, the initial pH of the medium, and boracic acid was investigated in the present study using a Vibrio harveyi BB170 reporter assay and quantitative reverse transcription-polymerase chain reaction (qRT-PCR) analysis. The results show that glucose can affect AI-2 synthesis to the greatest extent, and 3.0% glucose can stimulate K. pneumoniae to produce more AI-2, with a four times increase in activity compared with that of the control culture. According to our previous research, Type 2 QS in K. pneumoniae is luxS dependent. Therefore, the close relationship between glucose concentration and luxS transcription level was confirmed with qRT-PCR technology. The results show that the response of QS to a fluctuating glucose concentration was observed as a change in the amount of luxS RNA transcripts. A maximum of luxS transcription appeared during the exponential growth phase when the glucose concentration was 30.0 g/L. At the same time, AI-2 production was also slightly impacted by the low initial pH. It is noteworthy that the addition of boracic acid at microdosage (0.1 g/L) can also induce AI-2 synthesis. Presumably, in K. pneumoniae, the 4,5-dihydroxy-2,3-pentanedione cyclizes by the addition of borate and loss of water, is hydrated, and is converted to the final AI-2 signaling molecule.

Acupuncture Alters Expression of Insulin Signaling Related Molecules and Improves Insulin Resistance in OLETF Rats

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Xin-Yu Huang

2016-01-01

Full Text Available To determine effect of acupuncture on insulin resistance in Otsuka Long-Evans Tokushima Fatty (OLETF rats and to evaluate expression of insulin signaling components. Rats were divided into three groups: Sprague-Dawley (SD rats, OLETF rats, and acupuncture+OLETF rats. Acupuncture was subcutaneously applied to Neiguan (PC6, Zusanli (ST36, and Sanyinjiao (SP6; in contrast, acupuncture to Shenshu (BL23 was administered perpendicularly. For Neiguan (PC6 and Zusanli (ST36, needles were connected to an electroacupuncture (EA apparatus. Fasting blood glucose (FPG was measured by glucose oxidase method. Plasma fasting insulin (FINS and serum C peptide (C-P were determined by ELISA. Protein and mRNA expressions of insulin signaling molecules were determined by Western blot and real-time RT-PCR, respectively. OLETF rats exhibit increased levels of FPG, FINS, C-P, and homeostasis model assessment-estimated insulin resistance (HOMA-IR, which were effectively decreased by acupuncture treatment. mRNA expressions of several insulin signaling related molecules IRS1, IRS2, Akt2, aPKCζ, and GLUT4 were decreased in OLETF rats compared to SD controls. Expression of these molecules was restored back to normal levels upon acupuncture administration. PI3K-p85α was increased in OLETF rats; this increase was also reversed by acupuncture treatment. Acupuncture improves insulin resistance in OLETF rats, possibly via regulating expression of key insulin signaling related molecules.

Quorum sensing is a language of chemical signals and plays an ecological role in algal-bacterial interactions.

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Zhou, Jin; Lyu, Yihua; Richlen, Mindy; Anderson, Donald M; Cai, Zhonghua

2016-01-01

Algae are ubiquitous in the marine environment, and the ways in which they interact with bacteria are of particular interest in marine ecology field. The interactions between primary producers and bacteria impact the physiology of both partners, alter the chemistry of their environment, and shape microbial diversity. Although algal-bacterial interactions are well known and studied, information regarding the chemical-ecological role of this relationship remains limited, particularly with respect to quorum sensing (QS), which is a system of stimuli and response correlated to population density. In the microbial biosphere, QS is pivotal in driving community structure and regulating behavioral ecology, including biofilm formation, virulence, antibiotic resistance, swarming motility, and secondary metabolite production. Many marine habitats, such as the phycosphere, harbour diverse populations of microorganisms and various signal languages (such as QS-based autoinducers). QS-mediated interactions widely influence algal-bacterial symbiotic relationships, which in turn determine community organization, population structure, and ecosystem functioning. Understanding infochemicals-mediated ecological processes may shed light on the symbiotic interactions between algae host and associated microbes. In this review, we summarize current achievements about how QS modulates microbial behavior, affects symbiotic relationships, and regulates phytoplankton chemical ecological processes. Additionally, we present an overview of QS-modulated co-evolutionary relationships between algae and bacterioplankton, and consider the potential applications and future perspectives of QS.

Interference in Bacterial Quorum Sensing: A Biopharmaceutical Perspective

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Benjamin Rémy

2018-03-01

Full Text Available Numerous bacteria utilize molecular communication systems referred to as quorum sensing (QS to synchronize the expression of certain genes regulating, among other aspects, the expression of virulence factors and the synthesis of biofilm. To achieve this process, bacteria use signaling molecules, known as autoinducers (AIs, as chemical messengers to share information. Naturally occurring strategies that interfere with bacterial signaling have been extensively studied in recent years, examining their potential to control bacteria. To interfere with QS, bacteria use quorum sensing inhibitors (QSIs to block the action of AIs and quorum quenching (QQ enzymes to degrade signaling molecules. Recent studies have shown that these strategies are promising routes to decrease bacterial pathogenicity and decrease biofilms, potentially enhancing bacterial susceptibility to antimicrobial agents including antibiotics and bacteriophages. The efficacy of QSIs and QQ enzymes has been demonstrated in various animal models and are now considered in the development of new medical devices against bacterial infections, including dressings, and catheters for enlarging the therapeutic arsenal against bacteria.

Adjuvant ganglioside GM2-KLH/QS-21 vaccination versus observation after resection of primary tumor > 1.5 mm in patients with stage II melanoma

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Eggermont, Alexander M M; Suciu, Stefan; Rutkowski, Piotr

2013-01-01

The GM2 ganglioside is an antigen expressed in the majority of melanomas. The GM2-KLH/QS-21 vaccine induces high immunoglobulin M (IgM) and IgG antibody responses. The EORTC 18961 trial compared the efficacy of GM2-KLH/QS-21 vaccination versus observation....

Legume receptors perceive the rhizobial lipochitin oligosaccharide signal molecules by direct binding

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Broghammer, Angelique; Krusell, Lene; Blaise, Mickael

2012-01-01

Lipochitin oligosaccharides called Nod factors function as primary rhizobial signal molecules triggering legumes to develop new plant organs: root nodules that host the bacteria as nitrogen-fixing bacteroids. Here, we show that the Lotus japonicus Nod factor receptor 5 (NFR5) and Nod factor recep...

Study in Mice Links Key Signaling Molecule to Underlying Cause of Osteogenesis Imperfecta

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... Links Key Signaling Molecule to Underlying Cause of Osteogenesis Imperfecta By Kirstie Saltsman, Ph.D. | September 5, 2014 Vertebra from a mouse engineered to have osteogenesis imperfecta (upper panel). Following eight weeks of treatment with ...

Signaling lymphocytic activation molecules Slam and cancers: friends or foes?

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Fouquet, Gregory; Marcq, Ingrid; Debuysscher, Véronique; Bayry, Jagadeesh; Rabbind Singh, Amrathlal; Bengrine, Abderrahmane; Nguyen-Khac, Eric; Naassila, Mickael; Bouhlal, Hicham

2018-03-23

Signaling Lymphocytic Activation Molecules (SLAM) family receptors are initially described in immune cells. These receptors recruit both activating and inhibitory SH2 domain containing proteins through their Immunoreceptor Tyrosine based Switch Motifs (ITSMs). Accumulating evidence suggest that the members of this family are intimately involved in different physiological and pathophysiological events such as regulation of immune responses and entry pathways of certain viruses. Recently, other functions of SLAM, principally in the pathophysiology of neoplastic transformations have also been deciphered. These new findings may prompt SLAM to be considered as new tumor markers, diagnostic tools or potential therapeutic targets for controlling the tumor progression. In this review, we summarize the major observations describing the implications and features of SLAM in oncology and discuss the therapeutic potential attributed to these molecules.

Unfolding Role of a Danger Molecule Adenosine Signaling in Modulation of Microbial Infection and Host Cell Response

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Jaden S. Lee

2018-01-01

Full Text Available Ectonucleotidases CD39 and CD73, specific nucleotide metabolizing enzymes located on the surface of the host, can convert a pro-inflammatory environment driven by a danger molecule extracellular-ATP to an adenosine-mediated anti-inflammatory milieu. Accordingly, CD39/CD73 signaling has been strongly implicated in modulating the intensity, duration, and composition of purinergic danger signals delivered to host. Recent studies have eluted potential roles for CD39 and CD73 in selective triggering of a variety of host immune cells and molecules in the presence of pathogenic microorganisms or microbial virulence molecules. Growing evidence also suggests that CD39 and CD73 present complimentary, but likely differential, actions against pathogens to shape the course and severity of microbial infection as well as the associated immune response. Similarly, adenosine receptors A2A and A2B have been proposed to be major immunomodulators of adenosine signaling during chronic inflammatory conditions induced by opportunistic pathogens, such as oral colonizer Porphyromonas gingivalis. Therefore, we here review the recent studies that demonstrate how complex network of molecules in the extracellular adenosine signaling machinery and their interactions can reshape immune responses and may also be targeted by opportunistic pathogens to establish successful colonization in human mucosal tissues and modulate the host immune response.

Quorum sensing in gram-negative bacteria

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Wu, H.; Song, Z.J.; Høiby, N.

2004-01-01

Bacteria can communicate with each other by means of signal molecules to coordinate the behavior of the entire community, and the mechanism is referred to as quorum sensing (QS). Signal systems enable bacteria to sense the size of their densities by monitoring the concentration of the signal...... molecules. Among Gram-negative bacteria N-acyl-L-homoserine lactone (acyl-HSL)-dependent quorum sensing systems are particularly widespread. These systems are used to coordinate expression of phenotypes that are fundamental to the interaction of bacteria with each other and with their environment...

Autonomous control of metabolic state by a quorum sensing (QS)-mediated regulator for bisabolene production in engineered E. coli

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Kim, Eun-Mi; Min Woo, Han; Tian, Tian

2017-01-01

as it is self-regulated and does not require the addition of inducer compounds, which reduce operational costs for inducer. In this study, a QS system was developed for inducer-free production of the biofuel compound bisabolene from engineered E. coli. Seven variants of the Sensor plasmid, which carry the lux......I-luxR genes, and four variants of the Response plasmid, which carry bisabolene producing pathway genes under the control of the PluxI promoter, were designed for optimization of bisabolene production. Furthermore, a chromosome-integrated QS strain was engineered with the best combination of Sensor...

Quorum sensing signaling molecules produced by reference and emerging soft-rot bacteria (Dickeya and Pectobacterium spp..

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Alexandre Crépin

Full Text Available Several small diffusible molecules are involved in bacterial quorum sensing and virulence. The production of autoinducers-1 and -2, quinolone, indole and γ-amino butyrate signaling molecules was investigated in a set of soft-rot bacteria belonging to six Dickeya or Pectobacterium species including recent or emerging potato isolates.Using bacterial biosensors, immunoassay, and chromatographic analysis, we showed that soft-rot bacteria have the common ability to produce transiently during their exponential phase of growth the N-3-oxo-hexanoyl- or the N-3-oxo-octanoyl-l-homoserine lactones and a molecule of the autoinducer-2 family. Dickeya spp. produced in addition the indole-3-acetic acid in tryptophan-rich conditions. All these signaling molecules have been identified for the first time in the novel Dickeya solani species. In contrast, quinolone and γ-amino butyrate signals were not identified and the corresponding synthases are not present in the available genomes of soft-rot bacteria. To determine if the variations of signal production according to growth phase could result from expression modifications of the corresponding synthase gene, the respective mRNA levels were estimated by reverse transcriptase-PCR. While the N-acyl-homoserine lactone production is systematically correlated to the synthase expression, that of the autoinducer-2 follows the expression of an enzyme upstream in the activated methyl cycle and providing its precursor, rather than the expression of its own synthase.Despite sharing the S-adenosylmethionine precursor, no strong link was detected between the production kinetics or metabolic pathways of autoinducers-1 and -2. In contrast, the signaling pathway of autoinducer-2 seems to be switched off by the indole-3-acetic acid pathway under tryptophan control. It therefore appears that the two genera of soft-rot bacteria have similarities but also differences in the mechanisms of communication via the diffusible molecules

Quorum Sensing Signaling Molecules Produced by Reference and Emerging Soft-Rot Bacteria (Dickeya and Pectobacterium spp.)

Science.gov (United States)

Crépin, Alexandre; Barbey, Corinne; Beury-Cirou, Amélie; Hélias, Valérie; Taupin, Laure; Reverchon, Sylvie; Nasser, William; Faure, Denis; Dufour, Alain; Orange, Nicole; Feuilloley, Marc; Heurlier, Karin; Burini, Jean-François; Latour, Xavier

2012-01-01

Background Several small diffusible molecules are involved in bacterial quorum sensing and virulence. The production of autoinducers-1 and -2, quinolone, indole and γ-amino butyrate signaling molecules was investigated in a set of soft-rot bacteria belonging to six Dickeya or Pectobacterium species including recent or emerging potato isolates. Methodology/Principal Findings Using bacterial biosensors, immunoassay, and chromatographic analysis, we showed that soft-rot bacteria have the common ability to produce transiently during their exponential phase of growth the N-3-oxo-hexanoyl- or the N-3-oxo-octanoyl-l-homoserine lactones and a molecule of the autoinducer-2 family. Dickeya spp. produced in addition the indole-3-acetic acid in tryptophan-rich conditions. All these signaling molecules have been identified for the first time in the novel Dickeya solani species. In contrast, quinolone and γ-amino butyrate signals were not identified and the corresponding synthases are not present in the available genomes of soft-rot bacteria. To determine if the variations of signal production according to growth phase could result from expression modifications of the corresponding synthase gene, the respective mRNA levels were estimated by reverse transcriptase-PCR. While the N-acyl-homoserine lactone production is systematically correlated to the synthase expression, that of the autoinducer-2 follows the expression of an enzyme upstream in the activated methyl cycle and providing its precursor, rather than the expression of its own synthase. Conclusions/Significance Despite sharing the S-adenosylmethionine precursor, no strong link was detected between the production kinetics or metabolic pathways of autoinducers-1 and -2. In contrast, the signaling pathway of autoinducer-2 seems to be switched off by the indole-3-acetic acid pathway under tryptophan control. It therefore appears that the two genera of soft-rot bacteria have similarities but also differences in the

Applying Statistical and Complex Network Methods to Explore the Key Signaling Molecules of Acupuncture Regulating Neuroendocrine-Immune Network

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Kuo Zhang

2018-01-01

Full Text Available The mechanisms of acupuncture are still unclear. In order to reveal the regulatory effect of manual acupuncture (MA on the neuroendocrine-immune (NEI network and identify the key signaling molecules during MA modulating NEI network, we used a rat complete Freund’s adjuvant (CFA model to observe the analgesic and anti-inflammatory effect of MA, and, what is more, we used statistical and complex network methods to analyze the data about the expression of 55 common signaling molecules of NEI network in ST36 (Zusanli acupoint, and serum and hind foot pad tissue. The results indicate that MA had significant analgesic, anti-inflammatory effects on CFA rats; the key signaling molecules may play a key role during MA regulating NEI network, but further research is needed.

The generalized Q-S synchronization between the generalized Lorenz canonical form and the Roessler system

International Nuclear Information System (INIS)

Yang Yunqing; Chen Yong

2009-01-01

In this paper, we investigate the generalized Q-S synchronization between the generalized Lorenz canonical form and the Roessler system. Firstly, we transform an arbitrary generalized Lorenz system to the generalized Lorenz canonical form, and the relation between the parameter of the generalized Lorenz system and the parameter of the generalized Lorenz canonical form are shown. Secondly, we extend the scheme present by [Yan ZY. Chaos 2005;15:023902] to study the generalized Q-S synchronization between the generalized Lorenz canonical form and the Roessler system, the more general controller is obtained. By choosing different parameter in the generalized controller obtained here, without much extra effort, we can get the controller of synchronization between the Chen system and the Roessler system, the Lue system and the Roessler system, the classic Lorenz system and the Roessler system, the Hyperbolic Lorenz system and the Roessler system, respectively. Finally, numerical simulations are used to perform such synchronization and verify the effectiveness of the controller.

Interaction of plant cell signaling molecules, salicylic acid and jasmonic acid, with the mitochondria of Helicoverpa armigera.

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Akbar, S M D; Sharma, H C; Jayalakshmi, S K; Sreeramulu, K

2012-02-01

The cotton bollworm, Helicoverpa armigera is a polyphagous pest in Asia, Africa, and the Mediterranean Europe. Salicylic acid (SA) and jasmonic acid (JA) are the cell signaling molecules produced in response to insect attack in plants. The effect of these signaling molecules was investigated on the oxidative phosphorylation and oxidative stress of H. armigera. SA significantly inhibited the state III and state IV respiration, respiratory control index (RCI), respiratory complexes I and II, induced mitochondrial swelling, and cytochrome c release in vitro. Under in vivo conditions, SA induced state IV respiration as well as oxidative stress in time- and dose-dependent manner, and also inhibited the larval growth. In contrast, JA did not affect the mitochondrial respiration and oxidative stress. SA affected the growth and development of H. armigera, in addition to its function as signaling molecules involved in both local defense reactions at feeding sites and the induction of systemic acquired resistance in plants.

Q-S synchronization in 3D Henon-like map and generalized Henon map via a scalar controller

International Nuclear Information System (INIS)

Yan Zhenya

2005-01-01

In this Letter, a generalized, systematic and automatic backstepping scheme is developed to investigate the Q-S synchronization of two identical 3a discrete-time dynamical systems and two different 3D discrete-time dynamical systems. With the aid of symbolic-numeric computation, we use the proposed scheme to illustrate chaos synchronization between two identical 3D generalized Henon map and Q-S synchronization between two different 3D generalized Henon map and Henon-like map via a scalar controller, respectively. Moreover numerical simulations are used to verify the effectiveness of the proposed scheme. In addition, the scheme can be also applied to investigate the tracking problem in the discrete-time systems and to generate automatically the scalar controller in computer with the aid of symbolic-numeric computation

The acceptability, efficacy and safety of quinacrine non-surgical sterilization (QS), tubectomy and vasectomy in 5 provinces in the Red River Delta, Vietnam: a follow-up of 15,190 cases.

Science.gov (United States)

Hieu, D T; Luong, T T; Anh, P T; Ngoc, D H; Duong, L Q

2003-10-01

To compare the safety, efficacy and acceptability of quinacrine sterilization (QS), tubectomy and vasectomy in Vietnam. This study was initiated in January 1998 and completed in February 2000. A sample of 9 districts in 5 provinces, where the prevalence of QS was known to be high, was selected. Every person sterilized in these 9 districts between January 1, 1988 and March 31, 1998 was identified and systematically interviewed by family planning clinicians who had received special training for this project. A total of 15,982 sterilization users were identified and 15,190 were interviewed and examined, including a gynecologic exam, if needed: a follow-up rate of 95%. Of those interviewed, 9,753 used tubectomy, 3,734 used QS and 1,703 used vasectomy. All three methods were found to be safe, although morbidity associated with tubectomy was more serious than with QS or vasectomy. No deaths were reported. After more than 5 years of follow-up, tubectomy had the lowest failure rate: 1.0%, followed by 4.1% with vasectomy. A pregnancy rate of 13.2% was reported with quinacrine, although only a small fraction of these failures were confirmed. A strong preference for QS was found. QS has an important role to play in sterilization services in Vietnam.

Identification of AI-2 Quorum Sensing Inhibitors in Vibrio harveyi Through Structure-Based Virtual Screening.

Science.gov (United States)

Jiang, Tianyu; Zhu, Peng; Du, Lupei; Li, Minyong

2018-01-01

Quorum sensing (QS) is a cell-to-cell communication system that regulates gene expression as a result of the production and perception of signal molecules called autoinducers (AIs). AI-2 is a QS autoinducer produced by both Gram-negative and Gram-positive bacteria, in which it regulates intraspecies and interspecies communication. The identification of QS inhibitors is considered a promising strategy for the development of anti-virulence drugs with reduced selective pressure for resistance. Here we describe a high-throughput virtual screening approach to identify AI-2 quorum sensing inhibitors on the basis of Vibrio harveyi LuxPQ crystal structure. Seven potent inhibitors with IC 50 values in the micromolar range were selected with no effect or low effect on V. harveyi growth rate.

Hsp90α forms a stable complex at the cilium neck for the interaction of signalling molecules in IGF-1 receptor signalling.

Science.gov (United States)

Wang, Hongzhong; Zou, Xinle; Wei, Zhuang; Wu, Yuan; Li, Rongxia; Zeng, Rong; Chen, Zhengjun; Liao, Kan

2015-01-01

The primary cilium is composed of an axoneme that protrudes from the cell surface, a basal body beneath the membrane and a transition neck in between. It is a sensory organelle on the plasma membrane, involved in mediating extracellular signals. In the transition neck region of the cilium, the microtubules change from triplet to doublet microtubules. This region also contains the transition fibres that crosslink the axoneme with the membrane and the necklace proteins that regulate molecules being transported into and out of the cilium. In this protein-enriched, complex area it is important to maintain the correct assembly of all of these proteins. Here, through immunofluorescent staining and protein isolation, we identify the molecular chaperone Hsp90α clustered at the periciliary base. At the transition neck region, phosphorylated Hsp90α forms a stable ring around the axoneme. Heat shock treatment causes Hsp90α to dissipate and induces resorption of cilia. We further identify that Hsp90α at the transition neck region represents a signalling platform on which IRS-1 interacts with intracellular downstream signalling molecules involved in IGF-1 receptor signalling. © 2015. Published by The Company of Biologists Ltd.

Computational Exploration of Putative LuxR Solos in Archaea and Their Functional Implications in Quorum Sensing

Science.gov (United States)

Rajput, Akanksha; Kumar, Manoj

2017-01-01

LuxR solos are unexplored in Archaea, despite their vital role in the bacterial regulatory network. They assist bacteria in perceiving acyl homoserine lactones (AHLs) and/or non-AHLs signaling molecules for establishing intraspecies, interspecies, and interkingdom communication. In this study, we explored the potential LuxR solos of Archaea from InterPro v62.0 meta-database employing taxonomic, probable function, distribution, and evolutionary aspects to decipher their role in quorum sensing (QS). Our bioinformatics analyses showed that putative LuxR solos of Archaea shared few conserved domains with bacterial LuxR despite having less similarity within proteins. Functional characterization revealed their ability to bind various AHLs and/or non-AHLs signaling molecules that involve in QS cascades alike bacteria. Further, the phylogenetic study indicates that Archaeal LuxR solos (with less substitution per site) evolved divergently from bacteria and share distant homology along with instances of horizontal gene transfer. Moreover, Archaea possessing putative LuxR solos, exhibit the correlation between taxonomy and ecological niche despite being the inhabitant of diverse habitats like halophilic, thermophilic, barophilic, methanogenic, and chemolithotrophic. Therefore, this study would shed light in deciphering the role of the putative LuxR solos of Archaea to adapt varied habitats via multilevel communication with other organisms using QS. PMID:28515720

Computational Exploration of Putative LuxR Solos in Archaea and Their Functional Implications in Quorum Sensing

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Akanksha Rajput

2017-05-01

Full Text Available LuxR solos are unexplored in Archaea, despite their vital role in the bacterial regulatory network. They assist bacteria in perceiving acyl homoserine lactones (AHLs and/or non-AHLs signaling molecules for establishing intraspecies, interspecies, and interkingdom communication. In this study, we explored the potential LuxR solos of Archaea from InterPro v62.0 meta-database employing taxonomic, probable function, distribution, and evolutionary aspects to decipher their role in quorum sensing (QS. Our bioinformatics analyses showed that putative LuxR solos of Archaea shared few conserved domains with bacterial LuxR despite having less similarity within proteins. Functional characterization revealed their ability to bind various AHLs and/or non-AHLs signaling molecules that involve in QS cascades alike bacteria. Further, the phylogenetic study indicates that Archaeal LuxR solos (with less substitution per site evolved divergently from bacteria and share distant homology along with instances of horizontal gene transfer. Moreover, Archaea possessing putative LuxR solos, exhibit the correlation between taxonomy and ecological niche despite being the inhabitant of diverse habitats like halophilic, thermophilic, barophilic, methanogenic, and chemolithotrophic. Therefore, this study would shed light in deciphering the role of the putative LuxR solos of Archaea to adapt varied habitats via multilevel communication with other organisms using QS.

Simpson's Paradox and Confounding Factors in University Rankings: A Demonstration Using QS 2011-12 Data

Science.gov (United States)

Soh, Kay Cheng

2012-01-01

University ranking has become ritualistic in higher education. Ranking results are taken as bona fide by rank users. Ranking systems usually use large data sets from highly heterogeneous universities of varied backgrounds. This poses the problem of Simpson's Paradox and the lurking variables causing it. Using QS 2011-2012 Ranking data, the dual…

Inhibition of Coenzyme Qs Accumulation in Engineered Escherichia coli by High Concentration of Farnesyl Diphosphate

Science.gov (United States)

Samoudi, Mojtaba; Omid Yeganeh, Negar; Shahbani Zahiri, Hossein; Shariati, Parvin; Hajhosseini, Reza

2015-01-01

Background: Coenzyme Q 10 (CoQ 10 ) is an isoprenoid component used widely in nutraceutical industries. Farnesyl diphosphate synthase (FPPS) is a responsible enzyme for biosynthesis of farnesyl diphosphate (FPP), a key precursor for CoQs production. This research involved investigating the effect of FPPS over-expression on CoQs production in engineered CoQ 10 -producing Escherichia coli (E. coli). Methods: Two CoQ 10 -producing strains, as referred to E. coli Ba and E. coli Br, were transformed by the encoding gene for FPPS (ispA) under the control of either the trc or P BAD promoters. Results: Over-expression of ispA under the control of P BAD promoter led to a relative increase in CoQ 10 production only in recombinant E. coli Br although induction by arabinose resulted in partial reduction of CoQ 10 production in both recombinant E. coli Ba and E. coli Br strains. Over-expression of ispA under the control of stronger trc promoter, however, led to a severe decrease in CoQ 10 production in both recombinant E. coli Ba and E. coli Br strains, as reflected by reductions from 629±40 to 30±13 and 564±28 to 80±14 μg/g Dried Cell Weight (DCW), respectively. The results showed high level of FPP reduces endogenous CoQ 8 production as well and that CoQs are produced in a complimentary manner, as the increase in production of one decreases the production of the other. Conclusion: The reduction in CoQ 10 production can be a result of Dds inhibition by high FPP concentration. Therefore, more effort is needed to verify the role of intermediate metabolite concentration and to optimize production of CoQ 10 . PMID:26306151

Composition, anti-quorum sensing and antimicrobial activity of essential oils from Lippia alba

Directory of Open Access Journals (Sweden)

Jesus Olivero-Verbel

2014-09-01

Full Text Available Many Gram-negative pathogens have the ability to produce N-acylhomoserine lactones (AHLs as signal molecules for quorum sensing (QS. This cell-cell communication system allows them to coordinate gene expression and regulate virulence. Strategies to inhibit QS are promising for the control of infectious diseases or antibiotic resistant bacterial pathogens. The aim of the present study was to evaluate the anti-quorum sensing (anti-QS and antibacterial potential of five essential oils isolated from Lippia alba on the Tn-5 mutant of Chromobacterium violaceum CV026, and on the growth of the gram-positive bacteria S. aureus ATCC 25923. The anti-QS activity was detected through the inhibition of the QS-controlled violacein pigment production by the sensor bacteria. Results showed that two essential oils from L. alba, one containing the greatest geranial:neral and the other the highest limonene:carvone concentrations, were the most effective QS inhibitors. Both oils also had small effects on cell growth. Moreover, the geranial/neral chemotype oil also produced the maximum zone of growth inhibition against S. aureus ATCC 25923. These data suggest essential oils from L. alba have promising properties as QS modulators, and present antibacterial activity on S. aureus.

Mapping quorum sensing onto neural networks to understand collective decision making in heterogeneous microbial communities

Science.gov (United States)

Yusufaly, Tahir I.; Boedicker, James Q.

2017-08-01

Microbial communities frequently communicate via quorum sensing (QS), where cells produce, secrete, and respond to a threshold level of an autoinducer (AI) molecule, thereby modulating gene expression. However, the biology of QS remains incompletely understood in heterogeneous communities, where variant bacterial strains possess distinct QS systems that produce chemically unique AIs. AI molecules bind to ‘cognate’ receptors, but also to ‘non-cognate’ receptors found in other strains, resulting in inter-strain crosstalk. Understanding these interactions is a prerequisite for deciphering the consequences of crosstalk in real ecosystems, where multiple AIs are regularly present in the same environment. As a step towards this goal, we map crosstalk in a heterogeneous community of variant QS strains onto an artificial neural network model. This formulation allows us to systematically analyze how crosstalk regulates the community’s capacity for flexible decision making, as quantified by the Boltzmann entropy of all QS gene expression states of the system. In a mean-field limit of complete cross-inhibition between variant strains, the model is exactly solvable, allowing for an analytical formula for the number of variants that maximize capacity as a function of signal kinetics and activation parameters. An analysis of previous experimental results on the Staphylococcus aureus two-component Agr system indicates that the observed combination of variant numbers, gene expression rates and threshold concentrations lies near this critical regime of parameter space where capacity peaks. The results are suggestive of a potential evolutionary driving force for diversification in certain QS systems.

Signaling through intercellular adhesion molecule 1 (ICAM-1) in a B cell lymphoma line

DEFF Research Database (Denmark)

Holland, J; Owens, T

1997-01-01

Intercellular adhesion molecule 1 (ICAM-1) (CD54) is an adhesion molecule of the immunoglobulin superfamily. The interaction between ICAM-1 on B lymphocytes and leukocyte function-associated antigen 1 on T cells plays a major role in several aspects of the immune response, including T-dependent B...... cell activation. While it was originally believed that ICAM-1 played a purely adhesive role, recent evidence suggests that it can itself transduce biochemical signals. We demonstrate that cross-linking of ICAM-1 results in the up-regulation of class II major histocompatibility complex, and we...... investigate the biochemical mechanism for the signaling role of ICAM-1. We show that cross-linking of ICAM-1 on the B lymphoma line A20 induces an increase in tyrosine phosphorylation of several cellular proteins, including the Src family kinase p53/p56(lyn). In vitro kinase assays showed that Lyn kinase...

Quorum sensing circuit and reactive oxygen species resistance in Deinococcus sp.

Science.gov (United States)

Fernandez-Bunster, G; Gonzalez, C; Barros, J; Martinez, M

2012-12-01

Genus Deinococcus is characterized by an increased resistance toward reactive oxygen species (ROS). The chromosome of five strains belonging to this genus has been sequenced and the presence of a luxS-like gene was deduced from their genome sequences. The aim of this study was to assess if a complete QS circuit is present in Deinococcus sp. and if this QS is associated with ROS. Primers for searching luxS-like gene and the putative receptor gene, namely ai2R, were designed. AI-2 signal production was evaluated by luminescence analysis using Vibrio harveyi BB170 as reporter strain. AI-2 signal was also evaluated by competitive assays using cinnamaldehyde, ascorbic acid, and 3-mercaptopropionic acid as interfering molecules. Potassium tellurite and metronidazole were used as oxidative stressors. A luxS-like gene as well as an ai2R gene was detected in strain UDEC-P1 by PCR. Cell-free supernatant of strain UDEC-P1 culture induced luminescence in V. harveyi BB170, and this property was inhibited with the three interfering molecules. The oxidative stressors metronidazole and potassium tellurite decreased Deinococcus sp. viability, but increased luminescence of the reporter strain. The results demonstrate that both a functional luxS-like gene and a putative receptor for AI-2 signal are present in Deinococcus sp. strain UDEC-P1. This finding also suggests that a complete QS circuit is present in this genus, which could be related to oxidative stress.

Label-free molecular imaging of bacterial communities of the opportunistic pathogen Pseudomonas aeruginosa

Science.gov (United States)

Baig, Nameera; Polisetti, Sneha; Morales-Soto, Nydia; Dunham, Sage J. B.; Sweedler, Jonathan V.; Shrout, Joshua D.; Bohn, Paul W.

2016-09-01

Biofilms, such as those formed by the opportunistic human pathogen Pseudomonas aeruginosa are complex, matrix enclosed, and surface-associated communities of cells. Bacteria that are part of a biofilm community are much more resistant to antibiotics and the host immune response than their free-floating counterparts. P. aeruginosa biofilms are associated with persistent and chronic infections in diseases such as cystic fibrosis and HIV-AIDS. P. aeruginosa synthesizes and secretes signaling molecules such as the Pseudomonas quinolone signal (PQS) which are implicated in quorum sensing (QS), where bacteria regulate gene expression based on population density. Processes such as biofilms formation and virulence are regulated by QS. This manuscript describes the powerful molecular imaging capabilities of confocal Raman microscopy (CRM) and surface enhanced Raman spectroscopy (SERS) in conjunction with multivariate statistical tools such as principal component analysis (PCA) for studying the spatiotemporal distribution of signaling molecules, secondary metabolites and virulence factors in biofilm communities of P. aeruginosa. Our observations reveal that the laboratory strain PAO1C synthesizes and secretes 2-alkyl-4-hydroxyquinoline N-oxides and 2-alkyl-4-hydroxyquinolones in high abundance, while the isogenic acyl homoserine lactone QS-deficient mutant (ΔlasIΔrhlI) strain produces predominantly 2-alkyl-quinolones during biofilm formation. This study underscores the use of CRM, along with traditional biological tools such as genetics, for studying the behavior of microbial communities at the molecular level.

Pseudomonas aeruginosa quorum-sensing signal molecules interfere with dendritic cell-induced T-cell proliferation

DEFF Research Database (Denmark)

Skindersø, Mette Elena; Zeuthen, Louise; Pedersen, Susanne Brix

2009-01-01

Pseudomonas aeruginosa releases a wide array of toxins and tissue-degrading enzymes. Production of these malicious virulence factors is controlled by interbacterial communication in a process known as quorum sensing. An increasing body of evidence reveals that the bacterial signal molecule N-(3-o...

Revealing strategies of quorum sensing in Azospirillum brasilense strains Ab-V5 and Ab-V6.

Science.gov (United States)

Fukami, Josiane; Abrantes, Julia Laura Fernandes; Del Cerro, Pablo; Nogueira, Marco Antonio; Ollero, Francisco Javier; Megías, Manuel; Hungria, Mariangela

2018-01-01

Azospirillum brasilense is an important plant-growth promoting bacterium (PGPB) that requires several critical steps for root colonization, including biofilm and exopolysaccharide (EPS) synthesis and cell motility. In several bacteria these mechanisms are mediated by quorum sensing (QS) systems that regulate the expression of specific genes mediated by the autoinducers N-acyl-homoserine lactones (AHLs). We investigated QS mechanisms in strains Ab-V5 and Ab-V6 of A. brasilense, which are broadly used in commercial inoculants in Brazil. Neither of these strains carries a luxI gene, but there are several luxR solos that might perceive AHL molecules. By adding external AHLs we verified that biofilm and EPS production and cell motility (swimming and swarming) were regulated via QS in Ab-V5, but not in Ab-V6. Differences were observed not only between strains, but also in the specificity of LuxR-type receptors to AHL molecules. However, Ab-V6 was outstanding in indole acetic acid (IAA) synthesis and this molecule might mimic AHL signals. We also applied the quorum quenching (QQ) strategy, obtaining transconjugants of Ab-V5 and Ab-V6 carrying a plasmid with acyl-homoserine lactonase. When maize (Zea mays L.) was inoculated with the wild-type and transconjugant strains, plant growth was decreased with the transconjugant of Ab-V5-confirming the importance of an AHL-mediated QS system-but did not affect plant growth promotion by Ab-V6.

Two signaling molecules share a phosphotyrosine-containing binding site in the platelet-derived growth factor receptor.

OpenAIRE

Nishimura, R; Li, W; Kashishian, A; Mondino, A; Zhou, M; Cooper, J; Schlessinger, J

1993-01-01

Autophosphorylation sites of growth factor receptors with tyrosine kinase activity function as specific binding sites for Src homology 2 (SH2) domains of signaling molecules. This interaction appears to be a crucial step in a mechanism by which receptor tyrosine kinases relay signals to downstream signaling pathways. Nck is a widely expressed protein consisting exclusively of SH2 and SH3 domains, the overexpression of which causes cell transformation. It has been shown that various growth fac...

ZAP-70 and p72syk are signaling response elements through MHC class II molecules

DEFF Research Database (Denmark)

Kanner, S B; Grosmaire, L S; Blake, J

1995-01-01

Ligation of major histocompatibility complex (MHC) class II antigens expressed on antigen-activated human CD4+ T-lymphocytes induces early signal transduction events including the activation of tyrosine kinases, the tyrosine phosphorylation of phospholipase-C gamma 1 and the mobilization...... of intracellular calcium. Similar responses have been observed in B-cells following stimulation of MHC class II molecules, including the increased production of intracellular cAMP. In this report, we demonstrate that the ZAP-70 tyrosine kinase is a responsive signaling element following cross-linking of HLA...... by herbimycin A. MHC class II ligation on B-lymphocytes resulted in cell death, which was both qualitatively distinct from Fas-induced apoptosis and partially protected by herbimycin A pretreatment. Thus, ligation of MHC class II molecules expressed on human lymphocytes stimulates the ZAP-70/p72syk family...

Investigation of Pseudomonas aeruginosa quorum-sensing signaling system for identifying multiple inhibitors using molecular docking and structural analysis methodology.

Science.gov (United States)

Soheili, Vahid; Bazzaz, Bibi Sedigheh Fazly; Abdollahpour, Nooshin; Hadizadeh, Farzin

2015-12-01

Pseudomonas aeruginosa is an opportunistic human pathogen and a common Gram-negative bacterium in hospital-acquired infections. It causes death in many burn victims, cystic-fibrosis and neutropenic-cancer patients. It is known that P. aeruginosa biofilm maturation and production of cell-associated and extracellular virulence factors such as pyocyanin, elastase and rhamnolipids are under the control of a quorum-sensing (QS) system. Among several proteins involved in the Pseudomonas QS mechanism, LasR and PqsE play an important role in its cascade signaling system. They can cause increases in QS factors, biofilm maturation, and the production of virulence factors. Therefore, inhibition of these proteins can reduce the pathogenicity of P. aeruginosa. According to the structure of corresponding auto-inducers bound to these proteins, in silico calculations were performed with some non-steroidal anti-inflammatory drugs (NSAIDs) to estimate possible interactions and find the co-inhibitors of LasR and PqsE. The results showed that oxicams (Piroxicam and Meloxicam) can interact well with active sites of both proteins with the Ki of 119.43 nM and 4.0 μM for Meloxicam and 201.39 nM and 4.88 μM against LasR and PqsE, respectively. These findings suggested that Piroxicam and Meloxicam can be used as potential inhibitors for control of the P. aeruginosa QS signaling system and biofilm formation, and may be used in the design of multiple inhibitors. Copyright © 2015 Elsevier Ltd. All rights reserved.

Small Molecule Inhibitors of AI-2 Signaling in Bacteria: State-of-the-Art and Future Perspectives for Anti-Quorum Sensing Agents

Science.gov (United States)

Guo, Min; Gamby, Sonja; Zheng, Yue; Sintim, Herman O.

2013-01-01

Bacteria respond to different small molecules that are produced by other neighboring bacteria. These molecules, called autoinducers, are classified as intraspecies (i.e., molecules produced and perceived by the same bacterial species) or interspecies (molecules that are produced and sensed between different bacterial species). AI-2 has been proposed as an interspecies autoinducer and has been shown to regulate different bacterial physiology as well as affect virulence factor production and biofilm formation in some bacteria, including bacteria of clinical relevance. Several groups have embarked on the development of small molecules that could be used to perturb AI-2 signaling in bacteria, with the ultimate goal that these molecules could be used to inhibit bacterial virulence and biofilm formation. Additionally, these molecules have the potential to be used in synthetic biology applications whereby these small molecules are used as inputs to switch on and off AI-2 receptors. In this review, we highlight the state-of-the-art in the development of small molecules that perturb AI-2 signaling in bacteria and offer our perspective on the future development and applications of these classes of molecules. PMID:23994835

The adaptor molecule RIAM integrates signaling events critical for integrin-mediated control of immune function and cancer progression.

Science.gov (United States)

Patsoukis, Nikolaos; Bardhan, Kankana; Weaver, Jessica D; Sari, Duygu; Torres-Gomez, Alvaro; Li, Lequn; Strauss, Laura; Lafuente, Esther M; Boussiotis, Vassiliki A

2017-08-22

Lymphocyte activation requires adhesion to antigen-presenting cells. This is a critical event linking innate and adaptive immunity. Lymphocyte adhesion is accomplished through LFA-1, which must be activated by a process referred to as inside-out integrin signaling. Among the few signaling molecules that have been implicated in inside-out integrin activation in hematopoietic cells are the small guanosine triphosphatase (GTPase) Rap1 and its downstream effector Rap1-interacting molecule (RIAM), a multidomain protein that defined the Mig10-RIAM-lamellipodin (MRL) class of adaptor molecules. Through its various domains, RIAM is a critical node of signal integration for activation of T cells, recruits monomeric and polymerized actin to drive actin remodeling and cytoskeletal reorganization, and promotes inside-out integrin signaling in T cells. As a regulator of inside-out integrin activation, RIAM affects multiple functions of innate and adaptive immunity. The effects of RIAM on cytoskeletal reorganization and integrin activation have implications in cell migration and trafficking of cancer cells. We provide an overview of the structure and interactions of RIAM, and we discuss the implications of RIAM functions in innate and adaptive immunity and cancer. Copyright © 2017 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.

Identification and quantitation of signal molecule-dependent protein phosphorylation

KAUST Repository

Groen, Arnoud J.

2013-09-03

Phosphoproteomics is a fast-growing field that aims at characterizing phosphorylated proteins in a cell or a tissue at a given time. Phosphorylation of proteins is an important regulatory mechanism in many cellular processes. Gel-free phosphoproteome technique involving enrichment of phosphopeptide coupled with mass spectrometry has proven to be invaluable to detect and characterize phosphorylated proteins. In this chapter, a gel-free quantitative approach involving 15N metabolic labelling in combination with phosphopeptide enrichment by titanium dioxide (TiO2) and their identification by MS is described. This workflow can be used to gain insights into the role of signalling molecules such as cyclic nucleotides on regulatory networks through the identification and quantification of responsive phospho(proteins). © Springer Science+Business Media New York 2013.

Posttranslational protein S-palmitoylation and the compartmentalization of signaling molecules in neurons

Directory of Open Access Journals (Sweden)

SEAN I PATTERSON

2002-01-01

Full Text Available Protein domains play a fundamental role in the spatial and temporal organization of intracellular signaling systems. While protein phosphorylation has long been known to modify the interactions that underlie this organization, the dynamic cycling of lipids should now be included amongst the posttranslational processes determining specificity in signal transduction. The characteristics of this process are reminiscent of the properties of protein and lipid phosphorylation in determining compartmentalization through SH2 or PH domains. Recent studies have confirmed the functional importance of protein S-palmitoylation in the compartmentalization of signaling molecules that support normal physiological function in cell division and apoptosis, and synaptic transmission and neurite outgrowth. In neurons, S-palmitoylation and targeting of proteins to rafts are regulated differentially in development by a number of processes, including some related to synaptogenesis and synaptic plasticity. Alterations in the S-palmitoylation state of proteins substantially affect their cellular function, raising the possibility of new therapeutic targets in cancer and nervous system injury and disease.

KECERDASAN INTELEKTUAL, KECERDASAN EMOSIONAL DAN KECERDASAN SPIRITUAL (IESQ DALAM PERSPEKTIF AL QUR’AN (Telaah Analitis QS. Maryam Ayat 12 – 15

Directory of Open Access Journals (Sweden)

Luk Luk Nur Mufidah

2012-07-01

Full Text Available God creates human in the best kind of human creation as not only a passion, as Satan (Syetan has, not only has a sense as an angel has. Human lives with minds, feelings, wills and hearts (the Arabico is Aql, Nafs and Qalb so that he/she is able to change and cultivate the surrounding environment and to strive to meet the needs of life and achieve his/her goal. In the process of human effort is urgently needed to improve their quality of intelligence whether for intellect, emotional or spiritual. It explains In the QS. Maryam: 12-15 that Allah reveals how God gives good education to prophet of Yahya a.s to improve the intellect, emotional and spiritual. Based on the QS. Maryam: 12-15, there are several processes that must be passed by someone in order that he/she has a high IQ, EQ and SQ. To obtain the Intellect Intelligence (IQ, the Emotional Intelligence (EQ and the Spiritual Intelligence (SQ, human has to implement the seven concepts contained in Qs. Maryam: 12-15, namely: Concepts of Strong Educational, Concepts of Wisdom, Concept of Compassion, Concept of Tazkiyah, Concept of Taqwa, Concept of Birrul Walidain, Concept of Moderation or concepts of Arrogant Disobedience.

Plant Pathogenic Microbial Communication Affected by Elevated Temperature in Pectobacterium carotovorum subsp. carotovorum.

Science.gov (United States)

Saha, N D; Chaudhary, A; Singh, S D; Singh, D; Walia, S; Das, T K

2015-11-01

Gram-negative plant pathogenic bacteria regulate specific gene expression in a population density-dependent manner by sensing level of Acyl-Homoserine Lactone (HSL) molecules which they produce and liberate to the environment, called Quorum Sensing (QS). The production of virulence factors (extracellular enzyme viz. cellulase, pectinase, etc.) in Pectobacterium carotovorum subsp. carotovorum (Pcc) is under strong regulation of QS. The QS signal molecule, N-(3-oxohexanoyl)-L-Homoserine Lactone (OHHL) was found as the central regulatory system for the virulence factor production in Pcc and is also under strict regulation of external environmental temperature. Under seven different incubation temperatures (24, 26, 28, 30, 33, 35, and 37 °C) in laboratory condition, highest amount of OHHL (804 violacein unit) and highest (79 %) Disease Severity Index (DSI) were measured at 33 °C. The OHHL production kinetics showed accumulation of highest concentration of OHHL at late log phase of the growth but diminution in the concentration occurred during stationary phase onwards to death phase. At higher temperature (35 and 37 °C) exposure, OHHL was not at detectable range. The effect of temperature on virulence factor production is the concomitant effect of HSL production and degradation which justifies less disease severity index in cross-inoculated tomato fruits incubated at 35 and 37 °C. The nondetection of the OHHL in the elevated temperature may because of degradation as these signal molecules are quite sensitive and prone to get degraded under different physical factors. This result provides the rationale behind the highest disease severity up to certain elevated temperature and leaves opportunities for investigation on mutation, co-evolution of superior plant pathogen with more stable HSL signals-mediated pathogenesis under global warming context.

[Activation of the bioluminescence of the sensor Escherichia coli strains used for detecting N-acyl-homoserine lactones in the presence of nitrofurans and NO generators].

Science.gov (United States)

Zaĭtseva, Iu V; Granik, V G; Belik, A S; Koksharova, O A; Khmel', I A

2010-01-01

Nitrofurans (nitrofurazone, nitrofurantoin, furazidin, nifuroxazide), and nitric oxide generators (sodium nitroprusside and isosorbide mononitrate) in subinhibitory concentrations were shown to significantly increase the bioluminescence of the sensor Escherichia coli strains used for detecting N-acyl-homoserine lactones, signaling molecules of Quorum Sensing (QS) regulatory systems. The highest activation of bioluminescence (up to 250-400 fold) was observed in the presence of nitrofurazone on E. coli DH5alpha biosensors containing lux-reporter plasmids pSB401 or pSB536. However, this activation was not specifically associated with the functioning of QS systems. We suggest that the effect observed results from a direct action of nitrofurans and NO donors on the process of bioluminescence. The data indicate the necessity of using the biosensors that make it possible to detect specific effects of substances tested on QS regulation.

A proteomic analysis of Arabidopsis thaliana seedling responses to 3-oxo-octanoyl-homoserine lactone, a bacterial quorum-sensing signal

International Nuclear Information System (INIS)

Miao, Chunjuan; Liu, Fang; Zhao, Qian; Jia, Zhenhua; Song, Shuishan

2012-01-01

Highlights: ► 3OC8-HSL can change the expression of diverse proteins in Arabidopsis. ► 3OC8-HSL responsive proteins were identified using MALDI-TOF-MS. ► Plant could have an extensive range of functional responses to bacterial AHL. -- Abstract: N-acyl-homoserine lactones (AHLs) are a class of bacterial quorum-sensing (QS) signals that are commonly used by Gram-negative bacteria for cell-to-cell communication. Recently, it has become evident that AHLs can regulate plant root growth and trigger plant defense responses; however, little is known about the plant response mechanisms to bacterial QS signals. In this study, we used a proteomic approach to investigate the responses of Arabidopsis thaliana seedlings to N-3-oxo-octanoyl-homoserine lactone (3OC8-HSL), a bacterial QS signal. The results revealed that the abundance of 53 protein spots was significantly altered; two thirds of these proteins were found to be up-regulated after 3OC8-HSL treatment. Thirty-four proteins were identified using MALDI-TOF-MS. These 3OC8-HSL-responsive proteins, in addition to one protein of unknown function, are implicated in a variety of physiological processes, including metabolism of carbohydrate and energy, protein biosynthesis and quality control systems, defense response and signal transduction and cytoskeleton remodeling. Our bioinformatic analysis indicated that the chloroplasts are the intracellular organelles most influenced by the exposure to 3OC8-HSL. Our data indicate that plants have an extensive range of functional responses to bacterial AHLs that may play important roles in the interaction between plants and bacteria.

Non-thermal Plasma Exposure Rapidly Attenuates Bacterial AHL-Dependent Quorum Sensing and Virulence

Science.gov (United States)

Flynn, Padrig B.; Busetti, Alessandro; Wielogorska, Ewa; Chevallier, Olivier P.; Elliott, Christopher T.; Laverty, Garry; Gorman, Sean P.; Graham, William G.; Gilmore, Brendan F.

2016-01-01

The antimicrobial activity of atmospheric pressure non-thermal plasma has been exhaustively characterised, however elucidation of the interactions between biomolecules produced and utilised by bacteria and short plasma exposures are required for optimisation and clinical translation of cold plasma technology. This study characterizes the effects of non-thermal plasma exposure on acyl homoserine lactone (AHL)-dependent quorum sensing (QS). Plasma exposure of AHLs reduced the ability of such molecules to elicit a QS response in bacterial reporter strains in a dose-dependent manner. Short exposures (30–60 s) produce of a series of secondary compounds capable of eliciting a QS response, followed by the complete loss of AHL-dependent signalling following longer exposures. UPLC-MS analysis confirmed the time-dependent degradation of AHL molecules and their conversion into a series of by-products. FT-IR analysis of plasma-exposed AHLs highlighted the appearance of an OH group. In vivo assessment of the exposure of AHLs to plasma was examined using a standard in vivo model. Lettuce leaves injected with the rhlI/lasI mutant PAO-MW1 alongside plasma treated N-butyryl-homoserine lactone and n-(3-oxo-dodecanoyl)-homoserine lactone, exhibited marked attenuation of virulence. This study highlights the capacity of atmospheric pressure non-thermal plasma to modify and degrade AHL autoinducers thereby attenuating QS-dependent virulence in P. aeruginosa. PMID:27242335

Caffeine and REM sleep deprivation: Effect on basal levels of signaling molecules in area CA1.

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Alkadhi, Karim A; Alhaider, Ibrahim A

2016-03-01

We have investigated the neuroprotective effect of chronic caffeine treatment on basal levels of memory-related signaling molecules in area CA1 of sleep-deprived rats. Animals in the caffeine groups were treated with caffeine in drinking water (0.3g/l) for four weeks before they were REM sleep-deprived for 24h in the Modified Multiple Platforms paradigm. Western blot analysis of basal protein levels of plasticity- and memory-related signaling molecules in hippocampal area CA1 showed significant down regulation of the basal levels of phosphorylated- and total-CaMKII, phosphorylated- and total-CREB as well as those of BDNF and CaMKIV in sleep deprived rats. All these changes were completely prevented in rats that chronically consumed caffeine. The present findings suggest an important neuroprotective property of caffeine in sleep deprivation. Copyright © 2016 Elsevier Inc. All rights reserved.

T wave abnormalities, high body mass index, current smoking and high lipoprotein (a levels predict the development of major abnormal Q/QS patterns 20 years later. A population-based study

Directory of Open Access Journals (Sweden)

Sundstrom Johan

2006-03-01

Full Text Available Abstract Background Most studies on risk factors for development of coronary heart disease (CHD have been based on the clinical outcome of CHD. Our aim was to identify factors that could predict the development of ECG markers of CHD, such as abnormal Q/QS patterns, ST segment depression and T wave abnormalities, in 70-year-old men, irrespective of clinical outcome. Methods Predictors for development of different ECG abnormalities were identified in a population-based study using stepwise logistic regression. Anthropometrical and metabolic factors, ECG abnormalities and vital signs from a health survey of men at age 50 were related to ECG abnormalities identified in the same cohort 20 years later. Results At the age of 70, 9% had developed a major abnormal Q/QS pattern, but 63% of these subjects had not been previously hospitalized due to MI, while 57% with symptomatic MI between age 50 and 70 had no major Q/QS pattern at age 70. T wave abnormalities (Odds ratio 3.11, 95% CI 1.18–8.17, high lipoprotein (a levels, high body mass index (BMI and smoking were identified as significant independent predictors for the development of abnormal major Q/QS patterns. T wave abnormalities and high fasting glucose levels were significant independent predictors for the development of ST segment depression without abnormal Q/QS pattern. Conclusion T wave abnormalities on resting ECG should be given special attention and correlated with clinical information. Risk factors for major Q/QS patterns need not be the same as traditional risk factors for clinically recognized CHD. High lipoprotein (a levels may be a stronger risk factor for silent myocardial infarction (MI compared to clinically recognized MI.

S-aryl-L-cysteine sulphoxides and related organosulphur compounds alter oral biofilm development and AI-2-based cell-cell communication.

Science.gov (United States)

Kasper, S H; Samarian, D; Jadhav, A P; Rickard, A H; Musah, R A; Cady, N C

2014-11-01

To design and synthesize a library of structurally related, small molecules related to homologues of compounds produced by the plant Petiveria alliacea and determine their ability to interfere with AI-2 cell-cell communication and biofilm formation by oral bacteria. Many human diseases are associated with persistent bacterial biofilms. Oral biofilms (dental plaque) are problematic as they are often associated with tooth decay, periodontal disease and systemic disorders such as heart disease and diabetes. Using a microplate-based approach, a bio-inspired small molecule library was screened for anti-biofilm activity against the oral species Streptococcus mutans UA159, Streptococcus sanguis 10556 and Actinomyces oris MG1. To complement the static screen, a flow-based BioFlux microfluidic system screen was also performed under conditions representative of the human oral cavity. Several compounds were found to display biofilm inhibitory activity in all three of the oral bacteria tested. These compounds were also shown to inhibit bioluminescence by Vibrio harveyi and were thus inferred to be quorum sensing (QS) inhibitors. Due to the structural similarity of these compounds to each other, and to key molecules in AI-2 biosynthetic pathways, we propose that these molecules potentially reduce biofilm formation via antagonism of QS or QS-related pathways. This study highlights the potential for a non-antimicrobial-based strategy, focused on AI-2 cell-cell signalling, to control the development of dental plaque. Considering that many bacterial species use AI-2 cell-cell signalling, as well as the increased concern of the use of antimicrobials in healthcare products, such an anti-biofilm approach could also be used to control biofilms in environments beyond the human oral cavity. © 2014 The Society for Applied Microbiology.

Activation of stress signaling molecules in bat brain during arousal from hibernation.

Science.gov (United States)

Lee, Moonyong; Choi, Inho; Park, Kyoungsook

2002-08-01

Induction of glucose-regulated proteins (GRPs) is a ubiquitous intracellular response to stresses such as hypoxia, glucose starvation and acidosis. The induction of GRPs offers some protection against these stresses in vitro, but the specific role of GRPs in vivo remains unclear. Hibernating bats present a good in vivo model to address this question. The bats must overcome local high oxygen demand in tissue by severe metabolic stress during arousal thermogenesis. We used brain tissue of a temperate bat Rhinolopus ferrumequinum to investigate GRP induction by high metabolic oxygen demand and to identify associated signaling molecules. We found that during 30 min of arousal, oxygen consumption increased from nearly zero to 11.9/kg/h, which was about 8.7-fold higher than its active resting metabolic rate. During this time, body temperature rose from 7 degrees C to 35 degrees C, and levels of TNF-alpha and lactate in brain tissue increased 2-2.5-fold, indicating a high risk of oxygen shortage. Concomitantly, levels of GRP75, GRP78 and GRP94 increased 1.5-1.7-fold. At the same time, c-Jun N-terminal protein kinase (JNK) activity increased 6.4-fold, and extracellular signal-regulated protein kinase (ERK) activity decreased to a similar degree (6.1-fold). p38 MAPK activity was very low and remained unchanged during arousal. In addition, survival signaling molecules protein kinase B (Akt) and protein kinase C (PKC) were activated 3- and 5-fold, respectively, during arousal. Taken together, our results showed that bat brain undergoes high oxygen demand during arousal from hibernation. Up-regulation of GRP proteins and activation of JNK, PKCgamma and Akt may be critical for neuroprotection and the survival of bats during the repeated process.

Small Molecule Modulator of p53 Signaling Pathway: Application for Radiosensitizing or Radioprotection Agents

International Nuclear Information System (INIS)

Oh, Sang Taek; Cho, Mun Ju; Gwak, Jung Sug; Ryu, Min Jung; Song, Jie Young; Yun, Yeon Sook

2009-01-01

The tumor suppressor p53 is key molecule to protect the cell against genotoxic stress and..the most frequently mutated..protein..in cancer cells. Lack of functional p53..is accompanied by high rate of genomic instability, rapid tumor progression, resistance to anticancer therapy, and increased angiogenesis. In response to DNA damage, p53 protein rapidly accumulated through attenuated proteolysis and is also activated as transcription factor. Activated p53 up-regulates target genes involved in cell cycle arrest and/or apoptosis and then lead to suppression of malignant transformation and the maintenance of genomic integrity. Chemical genetics is a new technology to uncover the signaling networks that regulated biological phenotype using exogenous reagents such as small molecules. Analogous to classical forward genetic screens in model organism, this approach makes use of high throughput, phenotypic assay to identify small molecules that disrupt gene product function in a way that alters a phenotype of interest. Recently, interesting small molecules were identified from cell based high throughput screening and its target protein or mechanism of action were identified by various methods including affinity chromatography, protein array profiling, mRNA or phage display, transcription profiling, and RNA interference

Small Molecule Modulator of p53 Signaling Pathway: Application for Radiosensitizing or Radioprotection Agents

Energy Technology Data Exchange (ETDEWEB)

Oh, Sang Taek; Cho, Mun Ju; Gwak, Jung Sug; Ryu, Min Jung [PharmacoGenomics Research Center, Inje University, Busan (Korea, Republic of); Song, Jie Young; Yun, Yeon Sook [Korea Institute of Radiological and Medical Sciences, Seoul (Korea, Republic of)

2009-05-15

The tumor suppressor p53 is key molecule to protect the cell against genotoxic stress and..the most frequently mutated..protein..in cancer cells. Lack of functional p53..is accompanied by high rate of genomic instability, rapid tumor progression, resistance to anticancer therapy, and increased angiogenesis. In response to DNA damage, p53 protein rapidly accumulated through attenuated proteolysis and is also activated as transcription factor. Activated p53 up-regulates target genes involved in cell cycle arrest and/or apoptosis and then lead to suppression of malignant transformation and the maintenance of genomic integrity. Chemical genetics is a new technology to uncover the signaling networks that regulated biological phenotype using exogenous reagents such as small molecules. Analogous to classical forward genetic screens in model organism, this approach makes use of high throughput, phenotypic assay to identify small molecules that disrupt gene product function in a way that alters a phenotype of interest. Recently, interesting small molecules were identified from cell based high throughput screening and its target protein or mechanism of action were identified by various methods including affinity chromatography, protein array profiling, mRNA or phage display, transcription profiling, and RNA interference.

A proteomic analysis of Arabidopsis thaliana seedling responses to 3-oxo-octanoyl-homoserine lactone, a bacterial quorum-sensing signal

Energy Technology Data Exchange (ETDEWEB)

Miao, Chunjuan, E-mail: chunjuanjay@163.com [Biology Institute, Hebei Academy of Sciences, Shijiazhuang 050051 (China); Hebei Engineering and Technology Center of Microbiological Control on Main Crop Disease, Shijiazhuang 050051 (China); Liu, Fang, E-mail: liufang830818@126.com [Biology Institute, Hebei Academy of Sciences, Shijiazhuang 050051 (China); Hebei Engineering and Technology Center of Microbiological Control on Main Crop Disease, Shijiazhuang 050051 (China); Zhao, Qian, E-mail: zhqbluesea@163.com [Biology Institute, Hebei Academy of Sciences, Shijiazhuang 050051 (China); Hebei Engineering and Technology Center of Microbiological Control on Main Crop Disease, Shijiazhuang 050051 (China); Jia, Zhenhua, E-mail: zhenhuaj@hotmail.com [Biology Institute, Hebei Academy of Sciences, Shijiazhuang 050051 (China); Hebei Engineering and Technology Center of Microbiological Control on Main Crop Disease, Shijiazhuang 050051 (China); Song, Shuishan, E-mail: shuishans@hotmail.com [Biology Institute, Hebei Academy of Sciences, Shijiazhuang 050051 (China); Hebei Engineering and Technology Center of Microbiological Control on Main Crop Disease, Shijiazhuang 050051 (China)

2012-10-19

Highlights: Black-Right-Pointing-Pointer 3OC8-HSL can change the expression of diverse proteins in Arabidopsis. Black-Right-Pointing-Pointer 3OC8-HSL responsive proteins were identified using MALDI-TOF-MS. Black-Right-Pointing-Pointer Plant could have an extensive range of functional responses to bacterial AHL. -- Abstract: N-acyl-homoserine lactones (AHLs) are a class of bacterial quorum-sensing (QS) signals that are commonly used by Gram-negative bacteria for cell-to-cell communication. Recently, it has become evident that AHLs can regulate plant root growth and trigger plant defense responses; however, little is known about the plant response mechanisms to bacterial QS signals. In this study, we used a proteomic approach to investigate the responses of Arabidopsis thaliana seedlings to N-3-oxo-octanoyl-homoserine lactone (3OC8-HSL), a bacterial QS signal. The results revealed that the abundance of 53 protein spots was significantly altered; two thirds of these proteins were found to be up-regulated after 3OC8-HSL treatment. Thirty-four proteins were identified using MALDI-TOF-MS. These 3OC8-HSL-responsive proteins, in addition to one protein of unknown function, are implicated in a variety of physiological processes, including metabolism of carbohydrate and energy, protein biosynthesis and quality control systems, defense response and signal transduction and cytoskeleton remodeling. Our bioinformatic analysis indicated that the chloroplasts are the intracellular organelles most influenced by the exposure to 3OC8-HSL. Our data indicate that plants have an extensive range of functional responses to bacterial AHLs that may play important roles in the interaction between plants and bacteria.

Cross Talk between H2O2 and Interacting Signal Molecules under Plant Stress Response

Science.gov (United States)

Saxena, Ina; Srikanth, Sandhya; Chen, Zhong

2016-01-01

It is well established that oxidative stress is an important cause of cellular damage. During stress conditions, plants have evolved regulatory mechanisms to adapt to various environmental stresses. One of the consequences of stress is an increase in the cellular concentration of reactive oxygen species, which is subsequently converted to H2O2. H2O2 is continuously produced as the byproduct of oxidative plant aerobic metabolism. Organelles with a high oxidizing metabolic activity or with an intense rate of electron flow, such as chloroplasts, mitochondria, or peroxisomes are major sources of H2O2 production. H2O2 acts as a versatile molecule because of its dual role in cells. Under normal conditions, H2O2 immerges as an important factor during many biological processes. It has been established that it acts as a secondary messenger in signal transduction networks. In this review, we discuss potential roles of H2O2 and other signaling molecules during various stress responses. PMID:27200043

Protective effect of bioflavonoid myricetin enhances carbohydrate metabolic enzymes and insulin signaling molecules in streptozotocin-cadmium induced diabetic nephrotoxic rats.

Science.gov (United States)

Kandasamy, Neelamegam; Ashokkumar, Natarajan

2014-09-01

Diabetic nephropathy is the kidney disease that occurs as a result of diabetes. The present study was aimed to evaluate the therapeutic potential of myricetin by assaying the activities of key enzymes of carbohydrate metabolism, insulin signaling molecules and renal function markers in streptozotocin (STZ)-cadmium (Cd) induced diabetic nephrotoxic rats. After myricetin treatment schedule, blood and tissue samples were collected to determine plasma glucose, insulin, hemoglobin, glycosylated hemoglobin and renal function markers, carbohydrate metabolic enzymes in the liver and insulin signaling molecules in the pancreas and skeletal muscle. A significant increase of plasma glucose, glycosylated hemoglobin, urea, uric acid, creatinine, blood urea nitrogen (BUN), urinary albumin, glycogen phosphorylase, glucose-6-phosphatase, and fructose-1,6-bisphosphatase and a significant decrease of plasma insulin, hemoglobin, hexokinase, glucose-6-phosphate dehydrogenase, glycogen and glycogen synthase with insulin signaling molecule expression were found in the STZ-Cd induced diabetic nephrotoxic rats. The administration of myricetin significantly normalizes the carbohydrate metabolic products like glucose, glycated hemoglobin, glycogen phosphorylase and gluconeogenic enzymes and renal function markers with increase insulin, glycogen, glycogen synthase and insulin signaling molecule expression like glucose transporter-2 (GLUT-2), glucose transporter-4 (GLUT-4), insulin receptor-1 (IRS-1), insulin receptor-2 (IRS-2) and protein kinase B (PKB). Based on the data, the protective effect of myricetin was confirmed by its histological annotation of the pancreas, liver and kidney tissues. These findings suggest that myricetin improved carbohydrate metabolism which subsequently enhances glucose utilization and renal function in STZ-Cd induced diabetic nephrotoxic rats. Copyright © 2014 Elsevier Inc. All rights reserved.

Protective effect of bioflavonoid myricetin enhances carbohydrate metabolic enzymes and insulin signaling molecules in streptozotocin–cadmium induced diabetic nephrotoxic rats

Energy Technology Data Exchange (ETDEWEB)

Kandasamy, Neelamegam; Ashokkumar, Natarajan, E-mail: npashokkumar1@gmail.com

2014-09-01

Diabetic nephropathy is the kidney disease that occurs as a result of diabetes. The present study was aimed to evaluate the therapeutic potential of myricetin by assaying the activities of key enzymes of carbohydrate metabolism, insulin signaling molecules and renal function markers in streptozotocin (STZ)–cadmium (Cd) induced diabetic nephrotoxic rats. After myricetin treatment schedule, blood and tissue samples were collected to determine plasma glucose, insulin, hemoglobin, glycosylated hemoglobin and renal function markers, carbohydrate metabolic enzymes in the liver and insulin signaling molecules in the pancreas and skeletal muscle. A significant increase of plasma glucose, glycosylated hemoglobin, urea, uric acid, creatinine, blood urea nitrogen (BUN), urinary albumin, glycogen phosphorylase, glucose-6-phosphatase, and fructose-1,6-bisphosphatase and a significant decrease of plasma insulin, hemoglobin, hexokinase, glucose-6-phosphate dehydrogenase, glycogen and glycogen synthase with insulin signaling molecule expression were found in the STZ–Cd induced diabetic nephrotoxic rats. The administration of myricetin significantly normalizes the carbohydrate metabolic products like glucose, glycated hemoglobin, glycogen phosphorylase and gluconeogenic enzymes and renal function markers with increase insulin, glycogen, glycogen synthase and insulin signaling molecule expression like glucose transporter-2 (GLUT-2), glucose transporter-4 (GLUT-4), insulin receptor-1 (IRS-1), insulin receptor-2 (IRS-2) and protein kinase B (PKB). Based on the data, the protective effect of myricetin was confirmed by its histological annotation of the pancreas, liver and kidney tissues. These findings suggest that myricetin improved carbohydrate metabolism which subsequently enhances glucose utilization and renal function in STZ–Cd induced diabetic nephrotoxic rats. - Highlights: • Diabetic rats are more susceptible to cadmium nephrotoxicity. • Cadmium plays as a cumulative

Protective effect of bioflavonoid myricetin enhances carbohydrate metabolic enzymes and insulin signaling molecules in streptozotocin–cadmium induced diabetic nephrotoxic rats

International Nuclear Information System (INIS)

Kandasamy, Neelamegam; Ashokkumar, Natarajan

2014-01-01

Diabetic nephropathy is the kidney disease that occurs as a result of diabetes. The present study was aimed to evaluate the therapeutic potential of myricetin by assaying the activities of key enzymes of carbohydrate metabolism, insulin signaling molecules and renal function markers in streptozotocin (STZ)–cadmium (Cd) induced diabetic nephrotoxic rats. After myricetin treatment schedule, blood and tissue samples were collected to determine plasma glucose, insulin, hemoglobin, glycosylated hemoglobin and renal function markers, carbohydrate metabolic enzymes in the liver and insulin signaling molecules in the pancreas and skeletal muscle. A significant increase of plasma glucose, glycosylated hemoglobin, urea, uric acid, creatinine, blood urea nitrogen (BUN), urinary albumin, glycogen phosphorylase, glucose-6-phosphatase, and fructose-1,6-bisphosphatase and a significant decrease of plasma insulin, hemoglobin, hexokinase, glucose-6-phosphate dehydrogenase, glycogen and glycogen synthase with insulin signaling molecule expression were found in the STZ–Cd induced diabetic nephrotoxic rats. The administration of myricetin significantly normalizes the carbohydrate metabolic products like glucose, glycated hemoglobin, glycogen phosphorylase and gluconeogenic enzymes and renal function markers with increase insulin, glycogen, glycogen synthase and insulin signaling molecule expression like glucose transporter-2 (GLUT-2), glucose transporter-4 (GLUT-4), insulin receptor-1 (IRS-1), insulin receptor-2 (IRS-2) and protein kinase B (PKB). Based on the data, the protective effect of myricetin was confirmed by its histological annotation of the pancreas, liver and kidney tissues. These findings suggest that myricetin improved carbohydrate metabolism which subsequently enhances glucose utilization and renal function in STZ–Cd induced diabetic nephrotoxic rats. - Highlights: • Diabetic rats are more susceptible to cadmium nephrotoxicity. • Cadmium plays as a cumulative

Degradation of Bacterial Quorum Sensing Signaling Molecules by the Microscopic Yeast Trichosporon loubieri Isolated from Tropical Wetland Waters

Directory of Open Access Journals (Sweden)

Cheng-Siang Wong

2013-09-01

Full Text Available Proteobacteria produce N-acylhomoserine lactones as signaling molecules, which will bind to their cognate receptor and activate quorum sensing-mediated phenotypes in a population-dependent manner. Although quorum sensing signaling molecules can be degraded by bacteria or fungi, there is no reported work on the degradation of such molecules by basidiomycetous yeast. By using a minimal growth medium containing N-3-oxohexanoylhomoserine lactone as the sole source of carbon, a wetland water sample from Malaysia was enriched for microbial strains that can degrade N-acylhomoserine lactones, and consequently, a basidiomycetous yeast strain WW1C was isolated. Morphological phenotype and molecular analyses confirmed that WW1C was a strain of Trichosporon loubieri. We showed that WW1C degraded AHLs with N-acyl side chains ranging from 4 to 10 carbons in length, with or without oxo group substitutions at the C3 position. Re-lactonisation bioassays revealed that WW1C degraded AHLs via a lactonase activity. To the best of our knowledge, this is the first report of degradation of N-acyl-homoserine lactones and utilization of N-3-oxohexanoylhomoserine as carbon and nitrogen source for growth by basidiomycetous yeast from tropical wetland water; and the degradation of bacterial quorum sensing molecules by an eukaryotic yeast.

Two signaling molecules share a phosphotyrosine-containing binding site in the platelet-derived growth factor receptor.

Science.gov (United States)

Nishimura, R; Li, W; Kashishian, A; Mondino, A; Zhou, M; Cooper, J; Schlessinger, J

1993-11-01

Autophosphorylation sites of growth factor receptors with tyrosine kinase activity function as specific binding sites for Src homology 2 (SH2) domains of signaling molecules. This interaction appears to be a crucial step in a mechanism by which receptor tyrosine kinases relay signals to downstream signaling pathways. Nck is a widely expressed protein consisting exclusively of SH2 and SH3 domains, the overexpression of which causes cell transformation. It has been shown that various growth factors stimulate the phosphorylation of Nck and its association with autophosphorylated growth factor receptors. A panel of platelet-derived growth factor (PDGF) receptor mutations at tyrosine residues has been used to identify the Nck binding site. Here we show that mutation at Tyr-751 of the PDGF beta-receptor eliminates Nck binding both in vitro and in living cells. Moreover, the Y751F PDGF receptor mutant failed to mediate PDGF-stimulated phosphorylation of Nck in intact cells. A phosphorylated Tyr-751 is also required for binding of phosphatidylinositol-3 kinase to the PDGF receptor. Hence, the SH2 domains of p85 and Nck share a binding site in the PDGF receptor. Competition experiments with different phosphopeptides derived from the PDGF receptor suggest that binding of Nck and p85 is influenced by different residues around Tyr-751. Thus, a single tyrosine autophosphorylation site is able to link the PDGF receptor to two distinct SH2 domain-containing signaling molecules.

Inhibition of receptor tyrosine kinase signalling by small molecule agonist of T-cell protein tyrosine phosphatase

International Nuclear Information System (INIS)

Mattila, Elina; Marttila, Heidi; Sahlberg, Niko; Kohonen, Pekka; Tähtinen, Siri; Halonen, Pasi; Perälä, Merja; Ivaska, Johanna

2010-01-01

T-cell protein tyrosine phosphatase (TCPTP/TC45) is a ubiquitously expressed intra-cellular non-receptor protein tyrosine phosphatase involved in the negative regulation of several cancer relevant cellular signalling pathways. We have previously shown that interaction between the α-cytoplasmic tail of α1β1 integrin and TCPTP activates TCPTP by disrupting an inhibitory intra-molecular bond in TCPTP. Thus, inhibition of the regulatory interaction in TCPTP is a desirable strategy for TCPTP activation and attenuation of oncogenic RTK signalling. However, this is challenging with low molecular weight compounds. We developed a high-throughput compatible assay to analyse activity of recombinant TCPTP in vitro. Using this assay we have screened 64280 small molecules to identify novel agonists for TCPTP. Dose-dependent response to TCPTP agonist was performed using the in vitro assay. Inhibition effects and specificity of TCPTP agonists were evaluated using TCPTP expressing and null mouse embryonic fibroblasts. Western blot analysis was used to evaluate attenuation of PDGFRβ and EGFR phosphorylation. Inhibition of VEGF signalling was analysed with VEGF-induced endothelial cell sprouting assays. From the screen we identified six TCPTP agonists. Two compounds competed with α1-cytoplasmic domain for binding to TCPTP, suggesting that they activate TCPTP similar to α1-cyt by disrupting the intra-molecular bond in TCPTP. Importantly, one of the compounds (spermidine) displayed specificity towards TCPTP in cells, since TCPTP -/- cells were 43-fold more resistant to the compound than TCPTP expressing cells. This compound attenuates PDGFRβ and VEGFR2 signalling in cells in a TCPTP-dependent manner and functions as a negative regulator of EGFR phosphorylation in cancer cells. In this study we showed that small molecules mimicking TCPTP-α1 interaction can be used as TCPTP agonists. These data provide the first proof-of-concept description of the use of high-throughput screening

High-throughput screening identifies small molecules that bind to the RAS:SOS:RAS complex and perturb RAS signaling.

Science.gov (United States)

Burns, Michael C; Howes, Jennifer E; Sun, Qi; Little, Andrew J; Camper, DeMarco V; Abbott, Jason R; Phan, Jason; Lee, Taekyu; Waterson, Alex G; Rossanese, Olivia W; Fesik, Stephen W

2018-05-01

K-RAS is mutated in approximately 30% of human cancers, resulting in increased RAS signaling and tumor growth. Thus, RAS is a highly validated therapeutic target, especially in tumors of the pancreas, lung and colon. Although directly targeting RAS has proven to be challenging, it may be possible to target other proteins involved in RAS signaling, such as the guanine nucleotide exchange factor Son of Sevenless (SOS). We have previously reported on the discovery of small molecules that bind to SOS1, activate SOS-mediated nucleotide exchange on RAS, and paradoxically inhibit ERK phosphorylation (Burns et al., PNAS, 2014). Here, we describe the discovery of additional, structurally diverse small molecules that also bind to SOS1 in the same pocket and elicit similar biological effects. We tested >160,000 compounds in a fluorescence-based assay to assess their effects on SOS-mediated nucleotide exchange. X-Ray structures revealed that these small molecules bind to the CDC25 domain of SOS1. Compounds that elicited high levels of nucleotide exchange activity in vitro increased RAS-GTP levels in cells, and inhibited phospho ERK levels at higher treatment concentrations. The identification of structurally diverse SOS1 binding ligands may assist in the discovery of new molecules designed to target RAS-driven tumors. Copyright © 2018 Elsevier Inc. All rights reserved.

Discovering Small Molecule Inhibitors Targeted to Ligand-Stimulated RAGE-DIAPH1 Signaling Transduction

Science.gov (United States)

Pan, Jinhong

The receptor of advanced glycation end product (RAGE) is a multiligand receptor of the immunoglobulin superfamily of cell surface molecules, which plays an important role in immune responses. Full-length RAGE includes three extracellular immunoglobulin domains, a transmembrane domain and an intracellular domain. It is a pattern recognition receptor that can bind diverse ligands. NMR spectroscopy and x-ray crystallization studies of the extracellular domains of RAGE indicate that RAGE ligands bind by distinct charge- and hydrophobicity-dependent mechanisms. It is found that calgranulin binding to the C1C2 domain or AGEs binding to the V domain activates extracellular signaling, which triggers interactions of the RAGE cytoplasmic tail (ctRAGE) with intracellular effector, such as diaphanous 1 (DIAPH1), to initiate signal transduction cascades. ctRAGE is essential for RAGE-ligand-mediated signal transduction and consequent modulation of gene expression and cellular properties. RAGE is over-expressed in diseased tissues of most RAGE-associated pathogenic conditions, such as complications of Alzheimer's diseases, diabetes, vascular diseases, inflammation, cancers and neurodegeneration. They are the major diseases affecting a large population worldwide. RAGE can function as a biomarker or drug target for these diseases. The cytoplasmic tail of RAGE can be used as a drug target to inhibit RAGE-induced intracellular signaling by small molecule inhibitors to treat RAGE-associated diseases. We developed a high throughput screening assay with which we probed a small molecule library of 58,000 compounds to find that 777 small molecules displayed 50% inhibition and 97 compounds demonstrated dose-dependent inhibition of the binding of ctRAGE-DIAPH1. Eventually, there were 13 compounds which displayed dose-dependent inhibition of ctRAGE binding to DIAPH1 and direct binding to ctRAGE analyzed by 15N HSQC-NMR and native tryptophan fluorescence titration experiments; thus, they were

Real-time single-molecule co-immunoprecipitation analyses reveal cancer-specific Ras signalling dynamics

Science.gov (United States)

Lee, Hong-Won; Kyung, Taeyoon; Yoo, Janghyun; Kim, Tackhoon; Chung, Chaeuk; Ryu, Ji Young; Lee, Hanki; Park, Kihyun; Lee, Sangkyu; Jones, Walton D.; Lim, Dae-Sik; Hyeon, Changbong; Do Heo, Won; Yoon, Tae-Young

2013-01-01

Co-immunoprecipitation (co-IP) has become a standard technique, but its protein-band output provides only static, qualitative information about protein–protein interactions. Here we demonstrate a real-time single-molecule co-IP technique that generates real-time videos of individual protein–protein interactions as they occur in unpurified cell extracts. By analysing single Ras–Raf interactions with a 50-ms time resolution, we have observed transient intermediates of the protein–protein interaction and determined all the essential kinetic rates. Using this technique, we have quantified the active fraction of native Ras proteins in xenograft tumours, normal tissue and cancer cell lines. We demonstrate that the oncogenic Ras mutations selectively increase the active-Ras fraction by one order of magnitude, without affecting total Ras levels or single-molecule signalling kinetics. Our approach allows us to probe the previously hidden, dynamic aspects of weak protein–protein interactions. It also suggests a path forward towards precision molecular diagnostics at the protein–protein interaction level. PMID:23422673

Examining obligations to society for QS Stars best ranked universities in social responsibility

Directory of Open Access Journals (Sweden)

Păunescu Carmen

2017-12-01

Full Text Available Developing the local, regional, even national communities is often central to a university’s mission. This is a two-way process and both society and university itself should benefit from this collaboration. Universities around the world have been in the past decades required to leave their ivory tower and to become more involved in addressing the needs of the society and thus more relevant for the communities which they serve. They are expected to take a leadership role in implementation of the required change by contributing to community development through knowledge, innovations, skills and jobs. By taking a leading role in society and continuously innovating, universities will support communities with achieving a sustainable growth and therefore will contribute to increasing the well-being of society at large. The current paper aims to assess the university obligations to society by analyzing 27 universities around the world best ranked in social responsibility according to QS Stars University Rating 2016. In the paper, we discuss the extent to which different attributes of the university social responsibility are reflected among the initiatives and projects run by the universities included in the study. Also, an exploratory factor analysis was employed to identify underlying variables that explain the pattern of correlations between university social responsibility initiatives. Following the QS Stars methodology, the dimensions used to evaluate social responsibility of sampled universities included: community investment and development, social work and disaster relief, regional human capital development, and environmental impact. The results show that the level of involvement in social responsibility actions is high for all the universities included in the study. Also, the types of initiatives vary in terms of nature, intensity and impact for each one of the dimensions analyzed. Our research findings offer useful insights for both

Ocean acidification affects marine chemical communication by changing structure and function of peptide signalling molecules.

Science.gov (United States)

Roggatz, Christina C; Lorch, Mark; Hardege, Jörg D; Benoit, David M

2016-12-01

Ocean acidification is a global challenge that faces marine organisms in the near future with a predicted rapid drop in pH of up to 0.4 units by the end of this century. Effects of the change in ocean carbon chemistry and pH on the development, growth and fitness of marine animals are well documented. Recent evidence also suggests that a range of chemically mediated behaviours and interactions in marine fish and invertebrates will be affected. Marine animals use chemical cues, for example, to detect predators, for settlement, homing and reproduction. But, while effects of high CO 2 conditions on these behaviours are described across many species, little is known about the underlying mechanisms, particularly in invertebrates. Here, we investigate the direct influence of future oceanic pH conditions on the structure and function of three peptide signalling molecules with an interdisciplinary combination of methods. NMR spectroscopy and quantum chemical calculations were used to assess the direct molecular influence of pH on the peptide cues, and we tested the functionality of the cues in different pH conditions using behavioural bioassays with shore crabs (Carcinus maenas) as a model system. We found that peptide signalling cues are susceptible to protonation in future pH conditions, which will alter their overall charge. We also show that structure and electrostatic properties important for receptor binding differ significantly between the peptide forms present today and the protonated signalling peptides likely to be dominating in future oceans. The bioassays suggest an impaired functionality of the signalling peptides at low pH. Physiological changes due to high CO 2 conditions were found to play a less significant role in influencing the investigated behaviour. From our results, we conclude that the change of charge, structure and consequently function of signalling molecules presents one possible mechanism to explain altered behaviour under future oceanic p

Chronic Stress Decreases Basal Levels of Memory-Related Signaling Molecules in Area CA1 of At-Risk (Subclinical) Model of Alzheimer's Disease.

Science.gov (United States)

Alkadhi, Karim A; Tran, Trinh T

2015-08-01

An important factor that may affect the severity and time of onset of Alzheimer's disease (AD) is chronic stress. Epidemiological studies report that chronically stressed individuals are at an increased risk for developing AD. The purpose of this study was to reveal whether chronic psychosocial stress could hasten the appearance of AD symptoms including changes in basal levels of cognition-related signaling molecules in subjects who are at risk for the disease. We investigated the effect of chronic psychosocial stress on basal levels of memory-related signaling molecules in area CA1 of subclinical rat model of AD. The subclinical symptomless rat model of AD was induced by osmotic pump continuous intracerebroventricular (ICV) infusion of 160 pmol/day Aβ1-42 for 14 days. Rats were chronically stressed using the psychosocial stress intruder model. Western blot analysis of basal protein levels of important signaling molecules in hippocampal area CA1 showed no significant difference between the subclinical AD rat model and control rat. Following six weeks of psychosocial stress, molecular analysis showed that subclinical animals subjected to stress have significantly reduced basal levels of p-CaMKII and decreased p-CaMKII/t-CaMKII ratio as well as decreased basal levels of p-CREB, total CREB, and BDNF. The present results suggest that these changes in basal levels of signaling molecules may be responsible for impaired learning, memory, and LTP in this rat model, which support the proposition that chronic stress may accelerate the emergence of AD in susceptible individuals.

Endothelial juxtaposition of distinct adult stem cells activates angiogenesis signaling molecules in endothelial cells.

Science.gov (United States)

Mohammadi, Elham; Nassiri, Seyed Mahdi; Rahbarghazi, Reza; Siavashi, Vahid; Araghi, Atefeh

2015-12-01

Efficacy of therapeutic angiogenesis needs a comprehensive understanding of endothelial cell (EC) function and biological factors and cells that interplay with ECs. Stem cells are considered the key components of pro- and anti-angiogenic milieu in a wide variety of physiopathological states, and interactions of EC-stem cells have been the subject of controversy in recent years. In this study, the potential effects of three tissue-specific adult stem cells, namely rat marrow-derived mesenchymal stem cells (rBMSCs), rat adipose-derived stem cells (rADSCs) and rat muscle-derived satellite cells (rSCs), on the endothelial activation of key angiogenic signaling molecules, including VEGF, Ang-2, VEGFR-2, Tie-2, and Tie2-pho, were investigated. Human umbilical vein endothelial cells (HUVECs) and rat lung microvascular endothelial cells (RLMECs) were cocultured with the stem cells or incubated with the stem cell-derived conditioned media on Matrigel. Following HUVEC-stem cell coculture, CD31-positive ECs were flow sorted and subjected to western blotting to analyze potential changes in the expression of the pro-angiogenic signaling molecules. Elongation and co-alignment of the stem cells were seen along the EC tubes in the EC-stem cell cocultures on Matrigel, with cell-to-cell dye communication in the EC-rBMSC cocultures. Moreover, rBMSCs and rADSCs significantly improved endothelial tubulogenesis in both juxtacrine and paracrine manners. These two latter stem cells dynamically up-regulated VEGF, Ang-2, VREGR-2, and Tie-2 but down-regulated Tie2-pho and the Tie2-pho/Tie-2 ratio in HUVECs. Induction of pro-angiogenic signaling in ECs by marrow- and adipose-derived MSCs further indicates the significance of stem cell milieu in angiogenesis dynamics.

Pilot study of a heptavalent vaccine-keyhole limpet hemocyanin conjugate plus QS21 in patients with epithelial ovarian, fallopian tube, or peritoneal cancer

DEFF Research Database (Denmark)

Sabbatini, Paul J; Ragupathi, Govind; Hood, Chandra

2007-01-01

PURPOSE: To characterize the safety and immunogenicity of a heptavalent antigen-keyhole limpet hemocyanin (KLH) plus QS21 vaccine construct in patients with epithelial ovarian, fallopian tube, or peritoneal cancer in second or greater complete clinical remission. EXPERIMENTAL DESIGN: Eleven......). RESULTS: Eleven patients were included in the safety analysis; 9 of 11 patients remained on study for at least 2 weeks past fourth vaccination and were included in the immunologic analysis (two withdrew, disease progression). The vaccine was well tolerated. Self-limited and mild fatigue (maximum grade 2...... patients in this pilot trial received a heptavalent vaccine s.c. containing GM2 (10 microg), Globo-H (10 microg), Lewis Y (10 microg), Tn(c) (3 microg), STn(c) (3 microg), TF(c) (3 microg), and Tn-MUC1 (3 microg) individually conjugated to KLH and mixed with adjuvant QS21(100 microg). Vaccinations were...

The adhesion molecule NCAM promotes ovarian cancer progression via FGFR signalling

DEFF Research Database (Denmark)

Zecchini, Silvia; Bombardelli, Lorenzo; Decio, Alessandra

2011-01-01

glycoprotein involved in brain development and plasticity, in EOC. NCAM is absent from normal ovarian epithelium but becomes highly expressed in a subset of human EOC, in which NCAM expression is associated with high tumour grade, suggesting a causal role in cancer aggressiveness. We demonstrate that NCAM......Epithelial ovarian carcinoma (EOC) is an aggressive neoplasm, which mainly disseminates to organs of the peritoneal cavity, an event mediated by molecular mechanisms that remain elusive. Here, we investigated the expression and functional role of neural cell adhesion molecule (NCAM), a cell surface...... stimulates EOC cell migration and invasion in vitro and promotes metastatic dissemination in mice. This pro-malignant function of NCAM is mediated by its interaction with fibroblast growth factor receptor (FGFR). Indeed, not only FGFR signalling is required for NCAM-induced EOC cell motility, but targeting...

Synemin acts as a regulator of signalling molecules during skeletal muscle hypertrophy.

Science.gov (United States)

Li, Zhenlin; Parlakian, Ara; Coletti, Dario; Alonso-Martin, Sonia; Hourdé, Christophe; Joanne, Pierre; Gao-Li, Jacqueline; Blanc, Jocelyne; Ferry, Arnaud; Paulin, Denise; Xue, Zhigang; Agbulut, Onnik

2014-11-01

Synemin, a type IV intermediate filament (IF) protein, forms a bridge between IFs and cellular membranes. As an A-kinase-anchoring protein, it also provides temporal and spatial targeting of protein kinase A (PKA). However, little is known about its functional roles in either process. To better understand its functions in muscle tissue, we generated synemin-deficient (Synm(-) (/-)) mice. Synm(-) (/-) mice displayed normal development and fertility but showed a mild degeneration and regeneration phenotype in myofibres and defects in sarcolemma membranes. Following mechanical overload, Synm(-) (/-) mice muscles showed a higher hypertrophic capacity with increased maximal force and fatigue resistance compared with control mice. At the molecular level, increased remodelling capacity was accompanied by decreased myostatin (also known as GDF8) and atrogin (also known as FBXO32) expression, and increased follistatin expression. Furthermore, the activity of muscle-mass control molecules (the PKA RIIα subunit, p70S6K and CREB1) was increased in mutant mice. Finally, analysis of muscle satellite cell behaviour suggested that the absence of synemin could affect the balance between self-renewal and differentiation of these cells. Taken together, our results show that synemin is necessary to maintain membrane integrity and regulates signalling molecules during muscle hypertrophy. © 2014. Published by The Company of Biologists Ltd.

Ajoene, a Sulfur-Rich Molecule from Garlic, Inhibits Genes Controlled by Quorum Sensing

DEFF Research Database (Denmark)

Jakobsen, Tim Holm; van Gennip, Maria; Phipps, Richard Kerry

2012-01-01

the expression of specific genes involved in pathogenicity, is a possible drug target. Previous in vitro and in vivo studies revealed a significant inhibition of P. aeruginosa QS by crude garlic extract. By bioassay-guided fractionation of garlic extracts, we determined the primary QS inhibitor present in garlic...

Comparative gel-based phosphoproteomics in response to signaling molecules

KAUST Repository

Marondedze, Claudius; Lilley, Kathryn S.; Thomas, Ludivine

2013-01-01

The gel-based proteomics approach is a valuable technique for studying the characteristics of proteins. This technique has diverse applications ranging from analysis of a single protein to the study of the total cellular proteins. Further, protein quality and to some extent distribution can be first assessed by means of one-dimensional gel electrophoresis and then more informatively, for comparative analysis, using the two-dimensional gel electrophoresis technique. Here, we describe how to take advantage of the availability of fluorescent dyes to stain for a selective class of proteins on the same gel for the detection of both phospho- and total proteomes. This enables the co-detection of phosphoproteins as well as total proteins from the same gel and is accomplished by utilizing two different fluorescent stains, the ProQ-Diamond, which stains only phosphorylated proteins, and Sypro Ruby, which stains the entire subset of proteins. This workflow can be applied to gain insights into the regulatory mechanisms induced by signaling molecules such as cyclic nucleotides through the quantification and subsequent identification of responsive phospho- and total proteins. © Springer Science+Business Media New York 2013.

Comparative gel-based phosphoproteomics in response to signaling molecules

KAUST Repository

Marondedze, Claudius

2013-09-03

The gel-based proteomics approach is a valuable technique for studying the characteristics of proteins. This technique has diverse applications ranging from analysis of a single protein to the study of the total cellular proteins. Further, protein quality and to some extent distribution can be first assessed by means of one-dimensional gel electrophoresis and then more informatively, for comparative analysis, using the two-dimensional gel electrophoresis technique. Here, we describe how to take advantage of the availability of fluorescent dyes to stain for a selective class of proteins on the same gel for the detection of both phospho- and total proteomes. This enables the co-detection of phosphoproteins as well as total proteins from the same gel and is accomplished by utilizing two different fluorescent stains, the ProQ-Diamond, which stains only phosphorylated proteins, and Sypro Ruby, which stains the entire subset of proteins. This workflow can be applied to gain insights into the regulatory mechanisms induced by signaling molecules such as cyclic nucleotides through the quantification and subsequent identification of responsive phospho- and total proteins. © Springer Science+Business Media New York 2013.

Cloning, expression and characterization of two S-ribosylhomocysteine lyases from Lactobacillus plantarum YM-4-3: Implication of conserved and divergent roles in quorum sensing.

Science.gov (United States)

Song, Xiao-Dong; Liu, Chen-Jian; Huang, Shi-Hao; Li, Xiao-Ran; Yang, En; Luo, Yi-Yong

2018-05-01

Quorum sensing (QS) is a means of cell-to-cell communication that regulates, via small signalling molecules, expression of a series of genes and controls multicellular behaviour in many bacterial species. The enzyme S-ribosylhomocysteine lyase (LuxS) transforms S-ribosylhomocysteine (SRH) into 4, 5-dihydroxy-2, 3-pentanedione (DPD), the precursor of the interspecies QS signalling molecule autoinducer-2 (AI-2). In this study, two LuxS-coding genes, luxS1 and luxS2, with 70% sequence identity were isolated from Lactobacillus plantarum YM-4-3, and overexpressed in Escherichia coli BL21 (DE3), and the protein products were purified successfully. After incubation of LuxS1 or LuxS2 with SRH, the reaction products were able to induce Vibrio harveyi BB170 bioluminescence, clearly demonstrating that both LuxS1 and LuxS2 synthesize AI-2 from SRH in vitro. Ellman's assay results revealed optimal temperatures for LuxS1 and LuxS2 of 45 and 37 °C, respectively, and their activities were stimulated or inhibited by several metal ions and chemical reagents. In addition, enzyme kinetics data showed that K m , V max and K cat value of LuxS1 for the substrate (SRH) were higher than that of LuxS2. These results suggest that LuxS1 and LuxS2 mediate QS in a temperature-dependent manner and may play conserved roles in AI-2 synthesis but exhibit different activities in response to external environmental stress. To our knowledge, this paper is the first report of two luxS genes present in one bacterial genome and the subsequent comparative elucidation of their functions in AI-2 production. Collectively, our study provides a solid basis for future research concerning the AI-2/LuxS QS system in L. plantarum YM-4-3. Copyright © 2018 Elsevier Inc. All rights reserved.

Stenotrophomonas maltophilia responds to exogenous AHL signals through the LuxR solo SmoR (Smlt1839).

Science.gov (United States)

Martínez, Paula; Huedo, Pol; Martinez-Servat, Sònia; Planell, Raquel; Ferrer-Navarro, Mario; Daura, Xavier; Yero, Daniel; Gibert, Isidre

2015-01-01

Quorum Sensing (QS) mediated by Acyl Homoserine Lactone (AHL) molecules are probably the most widespread and studied among Gram-negative bacteria. Canonical AHL systems are composed by a synthase (LuxI family) and a regulator element (LuxR family), whose genes are usually adjacent in the genome. However, incomplete AHL-QS machinery lacking the synthase LuxI is frequently observed in Proteobacteria, and the regulator element is then referred as LuxR solo. It has been shown that certain LuxR solos participate in interspecific communication by detecting signals produced by different organisms. In the case of Stenotrophomonas maltophilia, a preliminary genome sequence analysis revealed numerous putative luxR genes, none of them associated to a luxI gene. From these, the hypothetical LuxR solo Smlt1839, here designated SmoR, presents a conserved AHL binding domain and a helix-turn-helix DNA binding motif. Its genomic organization-adjacent to hchA gene-indicate that SmoR belongs to the new family "LuxR regulator chaperone HchA-associated." AHL-binding assays revealed that SmoR binds to AHLs in-vitro, at least to oxo-C8-homoserine lactone, and it regulates operon transcription, likely by recognizing a conserved palindromic regulatory box in the hchA upstream region. Supplementation with concentrated supernatants from Pseudomonas aeruginosa, which contain significant amounts of AHLs, promoted swarming motility in S. maltophilia. Contrarily, no swarming stimulation was observed when the P. aeruginosa supernatant was treated with the lactonase AiiA from Bacillus subtilis, confirming that AHL contributes to enhance the swarming ability of S. maltophilia. Finally, mutation of smoR resulted in a swarming alteration and an apparent insensitivity to the exogenous AHLs provided by P. aeruginosa. In conclusion, our results demonstrate that S. maltophilia senses AHLs produced by neighboring bacteria through the LuxR solo SmoR, regulating population behaviors such as swarming

Interactions of electrons with biologically important molecules

International Nuclear Information System (INIS)

Pisklova, K.; Papp, P.; Stano, M.

2012-01-01

For the study of interactions of low-energy electrons with the molecules in the gas phase, the authors used electron-molecule cross-beam apparatus. The experiment is carried out in high vacuum, where molecules of the tested compound are inducted through a capillary. For purposes of this experiment the sample was electrically heated to 180 Deg C., giving a bundle of GlyGly molecules into the gas phase. The resulting signals can be evaluated in two different modes: mass spectrum - at continuous electron energy (e.g. 100 eV) they obtained the signal of intensity of the ions according to their mass to charge ratio; ionization and resonance spectra - for selected ion mass when the authors received the signal of intensity of the ions, depending on the energy of interacting electron.

Quorum Quenching Revisited—From Signal Decays to Signalling Confusion

Directory of Open Access Journals (Sweden)

Kok-Gan Chan

2012-04-01

Full Text Available In a polymicrobial community, while some bacteria are communicating with neighboring cells (quorum sensing, others are interrupting the communication (quorum quenching, thus creating a constant arms race between intercellular communication. In the past decade, numerous quorum quenching enzymes have been found and initially thought to inactivate the signalling molecules. Though this is widely accepted, the actual roles of these quorum quenching enzymes are now being uncovered. Recent evidence extends the role of quorum quenching to detoxification or metabolism of signalling molecules as food and energy source; this includes “signalling confusion”, a term coined in this paper to refer to the phenomenon of non-destructive modification of signalling molecules. While quorum quenching has been explored as a novel anti-infective therapy targeting, quorum sensing evidence begins to show the development of resistance against quorum quenching.

Small-molecule pheromones and hormones controlling nematode development.

Science.gov (United States)

Butcher, Rebecca A

2017-05-17

The existence of small-molecule signals that influence development in Caenorhabditis elegans has been known for several decades, but only in recent years have the chemical structures of several of these signals been established. The identification of these signals has enabled connections to be made between these small molecules and fundamental signaling pathways in C. elegans that influence not only development but also metabolism, fertility, and lifespan. Spurred by these important discoveries and aided by recent advances in comparative metabolomics and NMR spectroscopy, the field of nematode chemistry has the potential to expand dramatically in the coming years. This Perspective will focus on small-molecule pheromones and hormones that influence developmental events in the nematode life cycle (ascarosides, dafachronic acids, and nemamides), will cover more recent work regarding the biosynthesis of these signals, and will explore how the discovery of these signals is transforming our understanding of nematode development and physiology.

Detecting and identifying small molecules in a nanopore flux capacitor

International Nuclear Information System (INIS)

Bearden, Samuel; Zhang, Guigen; McClure, Ethan

2016-01-01

A new method of molecular detection in a metallic-semiconductor nanopore was developed and evaluated with experimental and computational methods. Measurements were made of the charging potential of the electrical double layer (EDL) capacitance as charge-carrying small molecules translocated the nanopore. Signals in the charging potential were found to be correlated to the physical properties of analyte molecules. From the measured signals, we were able to distinguish molecules with different valence charge or similar valence charge but different size. The relative magnitude of the signals from different analytes was consistent over a wide range of experimental conditions, suggesting that the detected signals are likely due to single molecules. Computational modeling of the nanopore system indicated that the double layer potential signal may be described in terms of disruption of the EDL structure due to the size and charge of the analyte molecule, in agreement with Huckel and Debye’s analysis of the electrical atmosphere of electrolyte solutions. (paper)

Impact of quorum sensing on the quality of fermented foods

DEFF Research Database (Denmark)

Johansen, Pernille; Jespersen, Lene

2017-01-01

The quality of fermented food highly dependents on the microorganisms involved, their metabolic activities and interactions. Recently, focus has been on quorum sensing (QS) being a cell density-dependent mechanism allowing adaptive responses. Specific QS molecules in prokaryotes and eukaryotes...

Adhesion molecules

CERN Document Server

Preedy, Victor R

2016-01-01

This book covers the structure and classification of adhesion molecules in relation to signaling pathways and gene expression. It discusses immunohistochemical localization, neutrophil migration, and junctional, functional, and inflammatory adhesion molecules in pathologies such as leukocyte decompression sickness and ischemia reperfusion injury. Highlighting the medical applications of current research, chapters cover diabetes, obesity, and metabolic syndrome; hypoxia; kidney disease; smoking, atrial fibrillation, and heart disease, the brain and dementia; and tumor proliferation. Finally, it looks at molecular imaging and bioinformatics, high-throughput technologies, and chemotherapy.

Differential Signaling and Sugar Exchanges in Response to Avirulent Pathogen- and Symbiont-Derived Molecules in Tobacco Cells

Directory of Open Access Journals (Sweden)

Carole Pfister

2017-11-01

Full Text Available Plants interact with microbes whose ultimate aim is to exploit plant carbohydrates for their reproduction. Plant–microbe interactions (PMIs are classified according to the nature of their trophic exchanges: while mutualistic microbes trade nutrients with plants, pathogens unilaterally divert carbohydrates. The early responses following microbe recognition and the subsequent control of plant sugar distribution are still poorly understood. To further decipher PMI functionality, we used tobacco cells treated with microbial molecules mimicking pathogenic or mutualistic PMIs, namely cryptogein, a defense elicitor, and chitotetrasaccharide (CO4, which is secreted by mycorrhizal fungi. CO4 was perceived by tobacco cells and triggered widespread transient signaling components such as a sharp cytosolic Ca2+ elevation, NtrbohD-dependent H2O2 production, and MAP kinase activation. These CO4-induced events differed from those induced by cryptogein, i.e., sustained events leading to cell death. Furthermore, cryptogein treatment inhibited glucose and sucrose uptake but not fructose uptake, and promoted the expression of NtSUT and NtSWEET sugar transporters, whereas CO4 had no effect on sugar uptake and only a slight effect on NtSWEET2B expression. Our results suggest that microbial molecules induce different signaling responses that reflect microbial lifestyle and the subsequent outcome of the interaction.

Novel approaches to mitigating bacterial biofilm formation and intercellular communication

Science.gov (United States)

Kasper, Stephen H.

Long thought of as solitary single-cell organisms, it is now widely accepted that bacteria can act and cooperate as social organisms. Phenomena such as biofilm formation and quorum sensing (QS) are two intimately intertwined cooperative behaviors that significantly contribute to the pathogenesis of many bacteria. Biofilms are surface associated communities of bacteria encased in a secreted extracellular matrix, which provides several advantages over an individualized lifestyle, such as increased protection from antimicrobial agents as well as enhanced opportunity for the exchange of genetic material. Bacterial QS is a system of population-based communication through the production, sensing, and response to chemical signals, often controlling the expression of diverse virulence factors (e.g. toxins, proteases). Biofilm formation and QS are cooperative processes that are often leveraged as bacteria coordinate infection processes, and can therefore be novel targets for anti-infective treatments that differ from conventional antibiotic treatment. Our lab has previously identified a novel class of small molecules that inhibit biofilm formation and disrupt QS by the pathogenic bacterium Pseudomonas aeruginosa. These organosulfur-based compounds are either natural products or related derivatives of the tropical plant Petiveria alliacea. Because oral biofilm (e.g. dental plaque) is a major conduit of oral and systemic disease, and is also a site for horizontal transfer for genes encoding antibiotic resistance, there exists a need for novel strategies for inhibiting oral biofilm development. Therefore, a small library (˜50 compounds) of structural derivatives was developed and screened for their ability to inhibit biofilm formation by multiple orally associated bacteria. The screening effort uncovered several related compounds that inhibited oral biofilm development. To determine how natural product-based organosulfur compounds could be inducing QS inhibitory effects, an

MHC class II molecules deliver costimulatory signals in human T cells through a functional linkage with IL-2-receptors

DEFF Research Database (Denmark)

Odum, Niels; Kanner, S B; Ledbetter, J A

1993-01-01

MHC class II-positive T cells are found in tissues involved in autoimmune and infectious disorders. Because stimulation of class II molecules by mAb or bacterial superantigens induces protein tyrosine phosphorylation through activation of PTK3 in T cells, we hypothesized that class II signals play...... tyrosine phosphorylation of specific substrates including PLC-gamma 1. Combined stimulation of IL-2R and class II molecules had an additive effect on tyrosine phosphorylation. Pretreatment of T cells with a protein tyrosine kinase inhibitor, herbimycin A, inhibited IL-2 and class II-induced proliferation...... a regulatory function in T cell activation. Here, we show that cross-linking HLA-DR and -DP but not -DQ molecules by immobilized mAb enhanced proliferative T cell responses to IL-2. In contrast, class II stimulation had no effect on IL-4-induced proliferation. The costimulatory effect was most pronounced...

Cardiac-Specific SOCS3 Deletion Prevents In Vivo Myocardial Ischemia Reperfusion Injury through Sustained Activation of Cardioprotective Signaling Molecules.

Directory of Open Access Journals (Sweden)

Takanobu Nagata

Full Text Available Myocardial ischemia reperfusion injury (IRI adversely affects cardiac performance and the prognosis of patients with acute myocardial infarction. Although myocardial signal transducer and activator of transcription (STAT 3 is potently cardioprotective during IRI, the inhibitory mechanism responsible for its activation is largely unknown. The present study aimed to investigate the role of the myocardial suppressor of cytokine signaling (SOCS-3, an intrinsic negative feedback regulator of the Janus kinase (JAK-STAT signaling pathway, in the development of myocardial IRI. Myocardial IRI was induced in mice by ligating the left anterior descending coronary artery for 1 h, followed by different reperfusion times. One hour after reperfusion, the rapid expression of JAK-STAT-activating cytokines was observed. We precisely evaluated the phosphorylation of cardioprotective signaling molecules and the expression of SOCS3 during IRI and then induced myocardial IRI in wild-type and cardiac-specific SOCS3 knockout mice (SOCS3-CKO. The activation of STAT3, AKT, and ERK1/2 rapidly peaked and promptly decreased during IRI. This decrease correlated with the induction of SOCS3 expression up to 24 h after IRI in wild-type mice. The infarct size 24 h after reperfusion was significantly reduced in SOCS3-CKO compared with wild-type mice. In SOCS3-CKO mice, STAT3, AKT, and ERK1/2 phosphorylation was sustained, myocardial apoptosis was prevented, and the expression of anti-apoptotic Bcl-2 family member myeloid cell leukemia-1 (Mcl-1 was augmented. Cardiac-specific SOCS3 deletion led to the sustained activation of cardioprotective signaling molecules including and prevented myocardial apoptosis and injury during IRI. Our findings suggest that SOCS3 may represent a key factor that exacerbates the development of myocardial IRI.

Identification of anti-virulence compounds that disrupt quorum-sensing regulated acute and persistent pathogenicity.

Directory of Open Access Journals (Sweden)

Melissa Starkey

2014-08-01

Full Text Available Etiological agents of acute, persistent, or relapsing clinical infections are often refractory to antibiotics due to multidrug resistance and/or antibiotic tolerance. Pseudomonas aeruginosa is an opportunistic Gram-negative bacterial pathogen that causes recalcitrant and severe acute chronic and persistent human infections. Here, we target the MvfR-regulated P. aeruginosa quorum sensing (QS virulence pathway to isolate robust molecules that specifically inhibit infection without affecting bacterial growth or viability to mitigate selective resistance. Using a whole-cell high-throughput screen (HTS and structure-activity relationship (SAR analysis, we identify compounds that block the synthesis of both pro-persistence and pro-acute MvfR-dependent signaling molecules. These compounds, which share a benzamide-benzimidazole backbone and are unrelated to previous MvfR-regulon inhibitors, bind the global virulence QS transcriptional regulator, MvfR (PqsR; inhibit the MvfR regulon in multi-drug resistant isolates; are active against P. aeruginosa acute and persistent murine infections; and do not perturb bacterial growth. In addition, they are the first compounds identified to reduce the formation of antibiotic-tolerant persister cells. As such, these molecules provide for the development of next-generation clinical therapeutics to more effectively treat refractory and deleterious bacterial-human infections.

Global and Phylogenetic Distribution of Quorum Sensing Signals, Acyl Homoserine Lactones, in the Family of Vibrionaceae

Directory of Open Access Journals (Sweden)

Bastian Barker Rasmussen

2014-11-01

Full Text Available Bacterial quorum sensing (QS and the corresponding signals, acyl homoserine lactones (AHLs, were first described for a luminescent Vibrio species. Since then, detailed knowledge has been gained on the functional level of QS; however, the abundance of AHLs in the family of Vibrionaceae in the environment has remained unclear. Three hundred and one Vibrionaceae strains were collected on a global research cruise and the prevalence and profile of AHL signals in this global collection were determined. AHLs were detected in 32 of the 301 strains using Agrobacterium tumefaciens and Chromobacterium violaceum reporter strains. Ethyl acetate extracts of the cultures were analysed by ultra-high performance liquid chromatography-high resolution mass spectrometry (MS with automated tandem MS confirmation for AHLs. N-(3-hydroxy-hexanoyl (OH-C6 and N-(3-hydroxy-decanoyl (OH-C10 homoserine lactones were the most common AHLs found in 17 and 12 strains, respectively. Several strains produced a diversity of different AHLs, including N-heptanoyl (C7 HL. AHL-producing Vibrionaceae were found in polar, temperate and tropical waters. The AHL profiles correlated with strain phylogeny based on gene sequence homology, however not with geographical location. In conclusion, a wide range of AHL signals are produced by a number of clades in the Vibrionaceae family and these results will allow future investigations of inter- and intra-species interactions within this cosmopolitan family of marine bacteria.

Interference of Pseudomonas aeruginosa signalling and biofilm formation for infection control

DEFF Research Database (Denmark)

Bjarnsholt, Thomas; Tolker-Nielsen, Tim; Høiby, Niels

2010-01-01

Pseudomonas aeruginosa is the best described bacterium with regards to quorum sensing (QS), in vitro biofilm formation and the development of antibiotic tolerance. Biofilms composed of P. aeruginosa are thought to be the underlying cause of many chronic infections, including those in wounds...... and in the lungs of patients with cystic fibrosis. In this review, we provide an overview of the molecular mechanisms involved in QS, QS-enabled virulence, biofilm formation and biofilm-enabled antibiotic tolerance. We now have substantial knowledge of the multicellular behaviour of P. aeruginosa in vitro. A major...

A novel screen-printed mast cell-based electrochemical sensor for detecting spoilage bacterial quorum signaling molecules (N-acyl-homoserine-lactones) in freshwater fish.

Science.gov (United States)

Jiang, Donglei; Liu, Yan; Jiang, Hui; Rao, Shengqi; Fang, Wu; Wu, Mangang; Yuan, Limin; Fang, Weiming

2018-04-15

A novel screen-printed cell-based electrochemical sensor was developed to assess bacterial quorum signaling molecules, N-acylhomoserine lactones (AHLs). Screen-printed carbon electrode (SPCE), which possesses excellent properties such as low-cost, disposable and energy-efficient, was modified with multi-walled carbon nanotubes (MWNTs) to improve electrochemical signals and enhance the sensitivity. Rat basophilic leukemia (RBL-2H3) mast cells encapsulated in alginate/graphene oxide (NaAgl/GO) hydrogel were immobilized on the MWNTs/SPCE to serve as recognition element. Electrochemical impedance spectroscopy (EIS) was employed to record the cell impedance signal as-influenced by Pseudomonas aeruginosa quorum-sensing molecule, N-3-oxododecanoyl homoserine lactone (3OC 12 -HSL). Experimental results show that 3OC 12 -HSL caused a significant decrease in cell viability in a dose dependent manner. The EIS value decreased with concentrations of 3OC 12 -HSL in the range of 0.1-1μM, and the detection limit for 3OC 12 -HSL was calculated to be 0.094μM. These results were confirmed via cell viability, SEM, TEM analysis. Next, the sensor was successfully applied to monitoring the production of AHLs by spoilage bacteria in three different freshwater fish juice samples which efficiently proved the practicability of this cell based method. Therefore, the proposed cell sensor may serve as an innovative and effective approach to the measurement of quorum signaling molecule and thus provides a new avenue for real-time monitoring the spoilage bacteria in freshwater fish production. Copyright © 2017 Elsevier B.V. All rights reserved.

Immunolocalization of notch signaling protein molecules in a maxillary chondrosarcoma and its recurrent tumor

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Siar CH

2010-10-01

Full Text Available Abstract Background Notch receptors are critical determinants of cell fate in a variety of organisms. Notch signaling is involved in the chondrogenic specification of neural crest cells. Aberrant Notch activity has been implicated in numerous human diseases including cancers; however its role in chondrogenic tumors has not been clarified. Method Tissue samples from a case of primary chondrosarcoma of the maxilla and its recurrent tumor were examined immunohistochemically for Notch1-4 and their ligands (Jagged1, Jagged2 and Delta1 expression. Results Both primary and recurrent tumors were histopathologically diagnosed as conventional hyaline chondrosarcoma (WHO Grade I. Hypercellular tumor areas strongly expressed Notch3 and Jagged1 in spindle and pleomorphic cells suggesting up-regulation of these protein molecules at sites of tumor proliferation. Expression patterns were distinct with some overlap. Differentiated malignant and atypical chondrocytes demonstrated variable expression levels of Jagged1, and weak to absent staining for Notch1, 4 and Delta1. Protein immunolocalization was largely membranous and cytoplasmic, sometimes outlining the lacunae of malignant chondrocytes. Hyaline cartilage demonstrated a diffuse or granular precipitation of Jagged1 suggesting presence of soluble Jagged1 activity at sites of abnormal chondrogenesis. No immunoreactivity for the other Notch members was observed. Calcified cartilage was consistently Notch-negative indicating down-regulation of Notch with cartilage maturation. Stromal components namely endothelial cells and fibroblasts variably expressed Notch1, 3 and Jagged1 but were mildly or non-reactive for the other members. Conclusions Results indicate that Notch signaling pathway may participate in cellular differentiation and proliferation in chondrosarcoma. Findings implicate Notch3 and Jagged1 as key molecules that influence the differentiation and maturation of cells of chondrogenic lineage.

Diverse profiles of N-acyl-homoserine lactone molecules found in cnidarians.

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Ransome, Emma; Munn, Colin B; Halliday, Nigel; Cámara, Miguel; Tait, Karen

2014-02-01

Many marine habitats, such as the surface and tissues of marine invertebrates, including corals, harbour diverse populations of microorganisms, which are thought to play a role in the health of their hosts and influence mutualistic and competitive interactions. Investigating the presence and stability of quorum sensing (QS) in these ecosystems may shed light on the roles and control of these bacterial communities. Samples of 13 cnidarian species were screened for the presence and diversity of N-acyl-homoserine lactones (AHLs; a prevalent type of QS molecule) using thin-layer chromatography and an Agrobacterium tumefaciens NTL4 biosensor. Ten of 13 were found to harbour species-specific, conserved AHL profiles. AHLs were confirmed in Anemonia viridis using liquid chromatography tandem mass spectrometry. To assess temporal role and stability, AHLs were investigated in A. viridis from intertidal pools over 16 h. Patterns of AHLs showed conserved profiles except for two mid-chain length AHLs, which increased significantly over the day, peaking at 20:00, but had no correlation with pool chemistry. Denaturing gel electrophoresis of RT-PCR-amplified bacterial 16S rRNA showed the presence of an active bacterial community that changed in composition alongside AHL profiles and contained a number of bands that affiliate with known AHL-producing bacteria. Investigations into the quorum sensing-controlled, species-specific roles of these bacterial communities and how these regulatory circuits are influenced by the coral host and members of the bacterial community are imperative to expand our knowledge of these interactions with respect to the maintenance of coral health. © 2013 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.

Information flow during gene activation by signaling molecules: ethylene transduction in Arabidopsis cells as a study system

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Díaz José

2009-05-01

Full Text Available Abstract Background We study root cells from the model plant Arabidopsis thaliana and the communication channel conformed by the ethylene signal transduction pathway. A basic equation taken from our previous work relates the probability of expression of the gene ERF1 to the concentration of ethylene. Results The above equation is used to compute the Shannon entropy (H or degree of uncertainty that the genetic machinery has during the decoding of the message encoded by the ethylene specific receptors embedded in the endoplasmic reticulum membrane and transmitted into the nucleus by the ethylene signaling pathway. We show that the amount of information associated with the expression of the master gene ERF1 (Ethylene Response Factor 1 can be computed. Then we examine the system response to sinusoidal input signals with varying frequencies to determine if the cell can distinguish between different regimes of information flow from the environment. Our results demonstrate that the amount of information managed by the root cell can be correlated with the frequency of the input signal. Conclusion The ethylene signaling pathway cuts off very low and very high frequencies, allowing a window of frequency response in which the nucleus reads the incoming message as a sinusoidal input. Out of this window the nucleus reads the input message as an approximately non-varying one. From this frequency response analysis we estimate: a the gain of the system during the synthesis of the protein ERF1 (~-5.6 dB; b the rate of information transfer (0.003 bits during the transport of each new ERF1 molecule into the nucleus and c the time of synthesis of each new ERF1 molecule (~21.3 s. Finally, we demonstrate that in the case of the system of a single master gene (ERF1 and a single slave gene (HLS1, the total Shannon entropy is completely determined by the uncertainty associated with the expression of the master gene. A second proposition shows that the Shannon entropy

The Pseudomonas aeruginosa N-acylhomoserine lactone quorum sensing molecules target IQGAP1 and modulate epithelial cell migration.

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Thommie Karlsson

Full Text Available Quorum sensing (QS signaling allows bacteria to control gene expression once a critical population density is achieved. The Gram-negative human pathogen Pseudomonas aeruginosa uses N-acylhomoserine lactones (AHL as QS signals, which coordinate the production of virulence factors and biofilms. These bacterial signals can also modulate human cell behavior. Little is known about the mechanisms of the action of AHL on their eukaryotic targets. Here, we found that N-3-oxo-dodecanoyl-L-homoserine lactone 3O-C(12-HSL modulates human intestinal epithelial Caco-2 cell migration in a dose- and time-dependent manner. Using new 3O-C(12-HSL biotin and fluorescently-tagged probes for LC-MS/MS and confocal imaging, respectively, we demonstrated for the first time that 3O-C(12-HSL interacts and co-localizes with the IQ-motif-containing GTPase-activating protein IQGAP1 in Caco-2 cells. The interaction between IQGAP1 and 3O-C(12-HSL was further confirmed by pull-down assay using a GST-tagged protein with subsequent Western blot of IQGAP1 and by identifying 3O-C(12-HSL with a sensor bioassay. Moreover, 3O-C(12-HSL induced changes in the phosphorylation status of Rac1 and Cdc42 and the localization of IQGAP1 as evidenced by confocal and STED microscopy and Western blots. Our findings suggest that the IQGAP1 is a novel partner for P. aeruginosa 3O-C(12-HSL and likely the integrator of Rac1 and Cdc42- dependent altered cell migration. We propose that the targeting of IQGAP1 by 3O-C(12-HSL can trigger essential changes in the cytoskeleton network and be an essential component in bacterial--human cell communication.

Activity, Abundance, and Localization of Quorum Sensing Receptors in Vibrio harveyi.

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Lorenz, Nicola; Shin, Jae Yen; Jung, Kirsten

2017-01-01

Quorum sensing (QS) is a process enabling a bacterial population to communicate via small molecules called autoinducers (AIs). This intercellular communication process allows single cells to synchronize their behavior within a population. The marine bacterium Vibrio harveyi ATCC BAA-1116 channels the information of three AI signals into one QS cascade. Three receptors perceive these AIs, the hybrid histidine kinases LuxN, Lux(P)Q and CqsS, to transduce the information to the histidine phosphotransfer (HPt) protein LuxU via phosphorelay, and finally to the response regulator LuxO. Hence, the level of phosphorylated LuxO depends on the AI concentrations. The phosphorylated LuxO (P-LuxO) controls the expression of small regulatory RNAs (sRNAs), which together with the RNA chaperon Hfq, destabilize the transcript of the master regulator luxR . LuxR is responsible for the induction and repression of several genes (e.g., for bioluminescence, exoprotease and siderophore production). In vivo studies with various mutants have demonstrated that the ratio between kinase and phosphatase activities of the individual QS receptors and therefore the P-LuxO/LuxO ratio is crucial not only for the output strength but also for the degree of noise. This study was undertaken to better understand the inherent design principles of this complex signaling cascade, which allows sensing and integration of different signals, but also the differentiated output in individual cells. Therefore, we quantitatively analyzed not only the enzymatic activities, but also the abundance and localization of the three QS receptors. We found that LuxN presents the highest capacity to phosphorylate LuxU, while the phosphatase activity was comparable to LuxQ and CqsS in vitro . In whole cells the copy number of LuxN was higher than that of LuxQ and CqsS, and further increased in the late exponential growth phase. Microscopy experiments indicate that LuxN and LuxQ form independent clusters. Altogether, these

Direct Targeting of β-Catenin by a Small Molecule Stimulates Proteasomal Degradation and Suppresses Oncogenic Wnt/β-Catenin Signaling

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So-Young Hwang

2016-06-01

Full Text Available The Wnt/β-catenin signaling pathway plays a major role in tissue homeostasis, and its dysregulation can lead to various human diseases. Aberrant activation of β-catenin is oncogenic and is a critical driver in the development and progression of human cancers. Despite the significant potential of targeting the oncogenic β-catenin pathway for cancer therapy, the development of specific inhibitors remains insufficient. Using a T cell factor (TCF-dependent luciferase-reporter system, we screened for small-molecule compounds that act against Wnt/β-catenin signaling and identified MSAB (methyl 3-{[(4-methylphenylsulfonyl]amino}benzoate as a selective inhibitor of Wnt/β-catenin signaling. MSAB shows potent anti-tumor effects selectively on Wnt-dependent cancer cells in vitro and in mouse cancer models. MSAB binds to β-catenin, promoting its degradation, and specifically downregulates Wnt/β-catenin target genes. Our findings might represent an effective therapeutic strategy for cancers addicted to the Wnt/β-catenin signaling pathway.

The Pseudomonas aeruginosa autoinducer dodecanoyl-homoserine lactone inhibits the putrescine synthesis in human cells

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Kristiansen, S.; Bjarnsholt, Thomas; Adeltoft, D.

2008-01-01

Pseudomonas aeruginosa uses acyl-homoserine lactones to coordinate gene transcription in a process called quorum sensing (QS). The QS molecules C-4-HSL and C-12-oxo-HSL are synthesized from the universal precursor S-adenosyl methionine, which is also a precursor of polyamines in human cells...

Basic roles of key molecules connected with NMDAR signaling pathway on regulating learning and memory and synaptic plasticity

Institute of Scientific and Technical Information of China (English)

Hui Wang; Rui-Yun Peng

2016-01-01

With key roles in essential brain functions ranging from the long-term potentiation (LTP) to synaptic plasticity,the N-methyl-D-aspartic acid receptor (NMDAR) can be considered as one of the fundamental glutamate receptors in the central nervous system.The role of NMDA R was first identified in synaptic plasticity and has been extensively studied.Some molecules,such as Ca2+,postsynaptic density 95 (PSD-95),calcium/calmodulin-dependent protein kinase Ⅱ (CaMK Ⅱ),protein kinase A (PKA),mitogen-activated protein kinase (MAPK) and cyclic adenosine monophosphate (cAMP) responsive element binding protein (CREB),are of special importance in learning and memory.This review mainly focused on the new research of key molecules connected with learning and memory,which played important roles in the NMDAR signaling pathway.

The Influence of Lead on Generation of Signalling Molecules and Accumulation of Flavonoids in Pea Seedlings in Response to Pea Aphid Infestation

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Agnieszka Woźniak

2017-08-01

Full Text Available The aim of this study was to investigate the effect of an abiotic factor, i.e., lead at various concentrations (low causing a hormesis effect and causing high toxicity effects, on the generation of signalling molecules in pea (Pisum sativum L. cv. Cysterski seedlings and then during infestation by the pea aphid (Acyrthosiphon pisum Harris. The second objective was to verify whether the presence of lead in pea seedling organs and induction of signalling pathways dependent on the concentration of this metal trigger defense responses to A. pisum. Therefore, the profile of flavonoids and expression levels of genes encoding enzymes of the flavonoid biosynthesis pathway (phenylalanine ammonialyase and chalcone synthase were determined. A significant accumulation of total salicylic acid (TSA and abscisic acid (ABA was recorded in the roots and leaves of pea seedlings growing on lead-supplemented medium and next during infestation by aphids. Increased generation of these phytohormones strongly enhanced the biosynthesis of flavonoids, including a phytoalexin, pisatin. This research provides insights into the cross-talk between the abiotic (lead and biotic factor (aphid infestation on the level of the generation of signalling molecules and their role in the induction of flavonoid biosynthesis.

Regulation Involved in Colonization of Intercellular Spaces of Host Plants in Ralstonia solanacearum

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Yasufumi Hikichi

2017-06-01

Full Text Available A soil-borne bacterium Ralstonia solanacearum invading plant roots first colonizes the intercellular spaces of the root, and eventually enters xylem vessels, where it replicates at high levels leading to wilting symptoms. After invasion into intercellular spaces, R. solanacearum strain OE1-1 attaches to host cells and expression of the hrp genes encoding components of the type III secretion system (T3SS. OE1-1 then constructs T3SS and secrets effectors into host cells, inducing expression of the host gene encoding phosphatidic acid phosphatase. This leads to suppressing plant innate immunity. Then, OE1-1 grows on host cells, inducing quorum sensing (QS. The QS contributes to regulation of OE1-1 colonization of intercellular spaces including mushroom-type biofilm formation on host cells, leading to its virulence. R. solanacearum strains AW1 and K60 produce methyl 3-hydroxypalmitate (3-OH PAME as a QS signal. The methyltransferase PhcB synthesizes 3-OH PAME. When 3-OH PAME reaches a threshold level, it increases the ability of the histidine kinase PhcS to phosphorylate the response regulator PhcR. This results in elevated levels of functional PhcA, the global virulence regulator. On the other hand, strains OE1-1 and GMI1000 produce methyl 3-hydroxymyristate (3-OH MAME as a QS signal. Among R. solanacearum strains, the deduced PhcB and PhcS amino acid sequences are related to the production of QS signals. R. solanacearum produces aryl-furanone secondary metabolites, ralfuranones, which are extracellularly secreted and required for its virulence, dependent on the QS. Interestingly, ralfuranones affect the QS feedback loop. Taken together, integrated signaling via ralfuranones influences the QS, contributing to pathogen virulence.

Single Molecule Raman Detection of Enkephalin on Silver Colloidal Particles

DEFF Research Database (Denmark)

Kneipp, Katrin; Kneipp, Holger; Abdali, Salim

2004-01-01

the Raman signal the enkephalin molecules have been attached to silver colloidal cluster structures. The experiments demonstrate that the SERS signal of the strongly enhanced ring breathing vibration of phenylalanine at 1000 cm-1 can be used as “intrinsic marker” for detecting a single enkephalin molecule...... and for monitoring its diffusion on the surface of the silver colloidal cluster without using a specific label molecule....

Disruption of Cell-to-Cell Signaling Does Not Abolish the Antagonism of Phaeobacter gallaeciensis toward the Fish Pathogen Vibrio anguillarum in Algal Systems

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Prol García, María Jesús; D'Alvise, Paul; Gram, Lone

2013-01-01

Quorum sensing (QS) regulates Phaeobacter gallaeciensis antagonism in broth systems; however, we demonstrate here that QS is not important for antagonism in algal cultures. QS mutants reduced Vibrio anguillarum to the same extent as the wild type. Consequently, a combination of probiotic Phaeobac...... Phaeobacter and QS inhibitors is a feasible strategy for aquaculture disease control....

Unilateral vestibular deafferentation-induced changes in calcium signaling-related molecules in the rat vestibular nuclear complex.

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Masumura, Chisako; Horii, Arata; Mitani, Kenji; Kitahara, Tadashi; Uno, Atsuhiko; Kubo, Takeshi

2007-03-23

Inquiries into the neurochemical mechanisms of vestibular compensation, a model of lesion-induced neuronal plasticity, reveal the involvement of both voltage-gated Ca(2+) channels (VGCC) and intracellular Ca(2+) signaling. Indeed, our previous microarray analysis showed an up-regulation of some calcium signaling-related genes such as the alpha2 subunit of L-type calcium channels, calcineurin, and plasma membrane Ca(2+) ATPase 1 (PMCA1) in the ipsilateral vestibular nuclear complex (VNC) following unilateral vestibular deafferentation (UVD). To further elucidate the role of calcium signaling-related molecules in vestibular compensation, we used a quantitative real-time polymerase chain reaction (PCR) method to confirm the microarray results and investigated changes in expression of these molecules at various stages of compensation (6 h to 2 weeks after UVD). We also investigated the changes in gene expression during Bechterew's phenomenon and the effects of a calcineurin inhibitor on vestibular compensation. Real-time PCR showed that genes for the alpha2 subunit of VGCC, PMCA2, and calcineurin were transiently up-regulated 6 h after UVD in ipsilateral VNC. A subsequent UVD, which induced Bechterew's phenomenon, reproduced a complete mirror image of the changes in gene expressions of PMCA2 and calcineurin seen in the initial UVD, while the alpha2 subunit of VGCC gene had a trend to increase in VNC ipsilateral to the second lesion. Pre-treatment by FK506, a calcineurin inhibitor, decelerated the vestibular compensation in a dose-dependent manner. Although it is still uncertain whether these changes in gene expression are causally related to the molecular mechanisms of vestibular compensation, this observation suggests that after increasing the Ca(2+) influx into the ipsilateral VNC neurons via up-regulated VGCC, calcineurin may be involved in their synaptic plasticity. Conversely, an up-regulation of PMCA2, a brain-specific Ca(2+) pump, would increase an efflux of Ca

Preface: Special Topic on Single-Molecule Biophysics.

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Makarov, Dmitrii E; Schuler, Benjamin

2018-03-28

Single-molecule measurements are now almost routinely used to study biological systems and processes. The scope of this special topic emphasizes the physics side of single-molecule observations, with the goal of highlighting new developments in physical techniques as well as conceptual insights that single-molecule measurements bring to biophysics. This issue also comprises recent advances in theoretical physical models of single-molecule phenomena, interpretation of single-molecule signals, and fundamental areas of statistical mechanics that are related to single-molecule observations. A particular goal is to illustrate the increasing synergy between theory, simulation, and experiment in single-molecule biophysics.

High throughput screening for small molecule enhancers of the interferon signaling pathway to drive next-generation antiviral drug discovery.

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Dhara A Patel

Full Text Available Most of current strategies for antiviral therapeutics target the virus specifically and directly, but an alternative approach to drug discovery might be to enhance the immune response to a broad range of viruses. Based on clinical observation in humans and successful genetic strategies in experimental models, we reasoned that an improved interferon (IFN signaling system might better protect against viral infection. Here we aimed to identify small molecular weight compounds that might mimic this beneficial effect and improve antiviral defense. Accordingly, we developed a cell-based high-throughput screening (HTS assay to identify small molecules that enhance the IFN signaling pathway components. The assay is based on a phenotypic screen for increased IFN-stimulated response element (ISRE activity in a fully automated and robust format (Z'>0.7. Application of this assay system to a library of 2240 compounds (including 2160 already approved or approvable drugs led to the identification of 64 compounds with significant ISRE activity. From these, we chose the anthracycline antibiotic, idarubicin, for further validation and mechanism based on activity in the sub-µM range. We found that idarubicin action to increase ISRE activity was manifest by other members of this drug class and was independent of cytotoxic or topoisomerase inhibitory effects as well as endogenous IFN signaling or production. We also observed that this compound conferred a consequent increase in IFN-stimulated gene (ISG expression and a significant antiviral effect using a similar dose-range in a cell-culture system inoculated with encephalomyocarditis virus (EMCV. The antiviral effect was also found at compound concentrations below the ones observed for cytotoxicity. Taken together, our results provide proof of concept for using activators of components of the IFN signaling pathway to improve IFN efficacy and antiviral immune defense as well as a validated HTS approach to identify

The Effects of Chinese Herbal Medicines on the Quorum Sensing-Regulated Virulence in Pseudomonas aeruginosa PAO1

OpenAIRE

Yee Meng Chong; Kah Yan How; Wai Fong Yin; Kok Gan Chan

2018-01-01

The quorum sensing (QS) system has been used by many opportunistic pathogenic bacteria to coordinate their virulence determinants in relation to cell-population density. As antibiotic-resistant bacteria are on the rise, interference with QS has been regarded as a novel way to control bacterial infections. As such, many plant-based natural products have been widely explored for their therapeutic roles. These natural products may contain anti-QS compounds that could block QS signals generation ...

Development and Psychometric Validation of the EDE-QS, a 12 Item Short Form of the Eating Disorder Examination Questionnaire (EDE-Q)

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Gideon, Nicole; Hawkes, Nick; Mond, Jonathan; Saunders, Rob; Tchanturia, Kate; Serpell, Lucy

2016-01-01

Objective The aim of this study was to develop and validate a short form of the Eating Disorder Examination Questionnaire (EDE-Q) for routine, including session by session, outcome assessment. Method The current, 28-item version (6.0) of the EDE-Q was completed by 489 individuals aged 18–72 with various eating disorders recruited from three UK specialist eating disorder services. Rasch analysis was carried out on factors identified by means of principal component analysis, which in combination with expert ratings informed the development of an EDE-Q short form. The shortened questionnaire’s reliability, validity and sensitivity was assessed based on online data collected from students of a UK university and volunteers with a history of eating disorders recruited from a national eating disorders charity aged 18–74 (N = 559). Results A 12-item short form, the Eating Disorder Examination Questionnaire Short (EDE-QS) was derived. The new measure showed high internal consistency (Cronbach’s α = .913) and temporal stability (ICC = .93; p eating disorder and comorbid psychopathology. It was sufficiently sensitive to distinguish between people with and without eating disorders. Discussion The EDE-QS is a brief, reliable and valid measure of eating disorder symptom severity that performs similarly to the EDE-Q and that lends itself for the use of sessional outcome monitoring in treatment and research. PMID:27138364

Role of Ethylene and Its Cross Talk with Other Signaling Molecules in Plant Responses to Heavy Metal Stress1

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Thao, Nguyen Phuong; Khan, M. Iqbal R.; Thu, Nguyen Binh Anh; Hoang, Xuan Lan Thi; Asgher, Mohd; Khan, Nafees A.; Tran, Lam-Son Phan

2015-01-01

Excessive heavy metals (HMs) in agricultural lands cause toxicities to plants, resulting in declines in crop productivity. Recent advances in ethylene biology research have established that ethylene is not only responsible for many important physiological activities in plants but also plays a pivotal role in HM stress tolerance. The manipulation of ethylene in plants to cope with HM stress through various approaches targeting either ethylene biosynthesis or the ethylene signaling pathway has brought promising outcomes. This review covers ethylene production and signal transduction in plant responses to HM stress, cross talk between ethylene and other signaling molecules under adverse HM stress conditions, and approaches to modify ethylene action to improve HM tolerance. From our current understanding about ethylene and its regulatory activities, it is believed that the optimization of endogenous ethylene levels in plants under HM stress would pave the way for developing transgenic crops with improved HM tolerance. PMID:26246451

Gamma-butyrolactone and furan signaling systems in Streptomyces.

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Sidda, John D; Corre, Christophe

2012-01-01

Streptomyces bacteria produce different classes of diffusible signaling molecules that trigger secondary metabolite production and/or morphological development within the cell population. The biosynthesis of gamma-butyrolactones (GBLs) and 2-alkyl-4-hydroxymethylfuran-3-carboxylic acids (AHFCAs) signaling molecules is related and involves an essential AfsA-like butenolide synthase. This chapter first describes the catalytic role of AfsA-like enzyme then provides details about methods for the discovery and characterization of potentially novel signaling molecules. In section 4, one approach for establishing the biological role of these signaling molecules is presented. Copyright © 2012 Elsevier Inc. All rights reserved.

Isolation and Molecular Characterization of Biofouling Bacteria and Profiling of Quorum Sensing Signal Molecules from Membrane Bioreactor Activated Sludge

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Harshad Lade

2014-02-01

Full Text Available The formation of biofilm in a membrane bioreactor depends on the production of various signaling molecules like N-acyl homoserine lactones (AHLs. In the present study, a total of 200 bacterial strains were isolated from membrane bioreactor activated sludge and screened for AHLs production using two biosensor systems, Chromobacterium violaceum CV026 and Agrobacterium tumefaciens A136. A correlation between AHLs production and biofilm formation has been made among screened AHLs producing strains. The 16S rRNA gene sequence analysis revealed the dominance of Aeromonas and Enterobacter sp. in AHLs production; however few a species of Serratia, Leclercia, Pseudomonas, Klebsiella, Raoultella and Citrobacter were also identified. The chromatographic characterization of sludge extract showed the presence of a broad range of quorum sensing signal molecules. Further identification of sludge AHLs by thin layer chromatography bioassay and high performance liquid chromatography confirms the presence of C4-HSL, C6-HSL, C8-HSL, 3-oxo-C8-HSL, C10-HSL, C12-HSL, 3-oxo-C12-HSL and C14-HSL. The occurrence of AHLs in sludge extract and dominance of Aeromonas and Enterobacter sp. in activated sludge suggests the key role of these bacterial strains in AHLs production and thereby membrane fouling.

Isolation and molecular characterization of biofouling bacteria and profiling of quorum sensing signal molecules from membrane bioreactor activated sludge.

Science.gov (United States)

Lade, Harshad; Paul, Diby; Kweon, Ji Hyang

2014-02-04

The formation of biofilm in a membrane bioreactor depends on the production of various signaling molecules like N-acyl homoserine lactones (AHLs). In the present study, a total of 200 bacterial strains were isolated from membrane bioreactor activated sludge and screened for AHLs production using two biosensor systems, Chromobacterium violaceum CV026 and Agrobacterium tumefaciens A136. A correlation between AHLs production and biofilm formation has been made among screened AHLs producing strains. The 16S rRNA gene sequence analysis revealed the dominance of Aeromonas and Enterobacter sp. in AHLs production; however few a species of Serratia, Leclercia, Pseudomonas, Klebsiella, Raoultella and Citrobacter were also identified. The chromatographic characterization of sludge extract showed the presence of a broad range of quorum sensing signal molecules. Further identification of sludge AHLs by thin layer chromatography bioassay and high performance liquid chromatography confirms the presence of C4-HSL, C6-HSL, C8-HSL, 3-oxo-C8-HSL, C10-HSL, C12-HSL, 3-oxo-C12-HSL and C14-HSL. The occurrence of AHLs in sludge extract and dominance of Aeromonas and Enterobacter sp. in activated sludge suggests the key role of these bacterial strains in AHLs production and thereby membrane fouling.

Effects of gelling agent and extracellular signaling molecules on the culturability of marine bacteria

DEFF Research Database (Denmark)

Rygaard, Anita Mac; Schmidt Thøgersen, Mariane; Nielsen, Kristian Fog

2017-01-01

Only 1 % of marine bacteria are currently culturable using standard laboratory procedures and this is a major obstacle for our understanding of the biology of marine microorganisms and for the discovery of novel microbial natural products. Therefore, the purpose of the present study was to invest......Only 1 % of marine bacteria are currently culturable using standard laboratory procedures and this is a major obstacle for our understanding of the biology of marine microorganisms and for the discovery of novel microbial natural products. Therefore, the purpose of the present study...... was to investigate if improved cultivation conditions, including the use of an alternative gelling agent, and supplementation with signaling molecules, could improve the culturability of bacteria from seawater. Substituting agar with gellan gum improved viable counts 3 – 40-fold, depending on medium composition...

Small molecule inhibitors of the Candida albicans budded-to-hyphal transition act through multiple signaling pathways.

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John Midkiff

Full Text Available The ability of the pathogenic yeast Candida albicans to interconvert between budded and hyphal growth states, herein termed the budded-to-hyphal transition (BHT, is important for C. albicans development and virulence. The BHT is under the control of multiple cell signaling pathways that respond to external stimuli, including nutrient availability, high temperature, and pH. Previous studies identified 21 small molecules that could inhibit the C. albicans BHT in response to carbon limitation in Spider media. However, the studies herein show that the BHT inhibitors had varying efficacies in other hyphal-inducing media, reflecting their varying abilities to block signaling pathways associated with the different media. Chemical epistasis analyses suggest that most, but not all, of the BHT inhibitors were acting through either the Efg1 or Cph1 signaling pathways. Notably, the BHT inhibitor clozapine, a FDA-approved drug used to treat atypical schizophrenia by inhibiting G-protein-coupled dopamine receptors in the brain, and several of its functional analogs were shown to act at the level of the Gpr1 G-protein-coupled receptor. These studies are the first step in determining the target and mechanism of action of these BHT inhibitors, which may have therapeutic anti-fungal utility in the future.

Co-ordinate regulation of distinct host cell signalling pathways by multifunctional enteropathogenic Escherichia coli effector molecules.

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Kenny, Brendan; Ellis, Sarah; Leard, Alan D; Warawa, Jonathan; Mellor, Harry; Jepson, Mark A

2002-05-01

Enteropathogenic Escherichia coli (EPEC) is a major cause of paediatric diarrhoea and a model for the family of attaching and effacing (A/E) pathogens. A/E pathogens encode a type III secretion system to transfer effector proteins into host cells. The EPEC Tir effector protein acts as a receptor for the bacterial surface protein intimin and is involved in the formation of Cdc42-independent, actin-rich pedestal structures beneath the adhered bacteria. In this paper, we demonstrate that EPEC binding to HeLa cells also induces Tir-independent, cytoskeletal rearrangement evidenced by the early, transient formation of filopodia-like structures at sites of infection. Filopodia formation is dependent on expression of the EPEC Map effector molecule - a protein that targets mitochondria and induces their dysfunction. We show that Map-induced filopodia formation is independent of mitochondrial targeting and is abolished by cellular expression of the Cdc42 inhibitory WASP-CRIB domain, demonstrating that Map has at least two distinct functions in host cells. The transient nature of the filopodia is related to an ability of EPEC to downregulate Map-induced cell signalling that, like pedestal formation, was dependent on both Tir and intimin proteins. The ability of Tir to downregulate filopodia was impaired by disrupting a putative GTPase-activating protein (GAP) motif, suggesting that Tir may possess such a function, with its interaction with intimin triggering this activity. Furthermore, we also found that Map-induced cell signalling inhibits pedestal formation, revealing that the cellular effects of Tir and Map must be co-ordinately regulated during infection. Possible implications of the multifunctional nature of EPEC effector molecules in pathogenesis are discussed.

Attenuation of quorum-sensing-dependent virulence factors and biofilm formation by medicinal plants against antibiotic resistant Pseudomonas aeruginosa

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P. Sankar Ganesh

2018-01-01

Full Text Available Pseudomonas aeruginosa use small signaling molecules such as acyl homoserine lactones (AHLs, which play an important role in release virulence factors and toxin for further establishment of host infection. Thus, involving with the QS system would provide alternative ways of preventing the pathogenicity. In the present study, totally six medicinal plants (Terminalia bellerica, Celastrus paniculatus, Kingiodendron pinnatum, Schleichera oleosa, Melastoma malabathricum, Garcinia gummi-gutta were screened for anti-QS activity using biomonitor strain of Chromobacterium violaceum CV12472. The primary screening of antimicrobial activity of all the plant extracts have inhibited the growth of tested bacterial species. Of these at the sub-minimum inhibitory concentration the methanol extract of T. bellerica (0.0625–0.5 mg/ml has significantly inhibited violacein production (20.07–66.22% in C. violaceum (CV12472. Consequently, the extract of T. bellerica has reduced the production of pyocyanin, exopolysaccharide and biofilm formation in P. aeruginosa strains. Fluorescence and scanning electron microscopy analysis confirmed the reduction of biofilm formation in P. aeruginosa strains when treated with T. bellerica. GC–MS analysis showed the active compounds inhibited the production of virulence factors of P. aeruginosa. The results suggest the possible use of this T. bellerica as an anti-QS and anti-biofilm agent to control Pseudomonas infection. Interference of QS provides an important means for the inhibition of bacterial virulence and thus aids in treatment strategies.

Microbial Regulation in Gorgonian Corals

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Laura D. Mydlarz

2012-06-01

Full Text Available Gorgonian corals possess many novel natural products that could potentially mediate coral-bacterial interactions. Since many bacteria use quorum sensing (QS signals to facilitate colonization of host organisms, regulation of prokaryotic cell-to-cell communication may represent an important bacterial control mechanism. In the present study, we examined extracts of twelve species of Caribbean gorgonian corals, for mechanisms that regulate microbial colonization, such as antibacterial activity and QS regulatory activity. Ethanol extracts of gorgonians collected from Puerto Rico and the Florida Keys showed a range of both antibacterial and QS activities using a specific Pseudomonas aeruginosa QS reporter, sensitive to long chain AHLs and a short chain N-acylhomoserine lactones (AHL biosensor, Chromobacterium violaceium. Overall, the gorgonian corals had higher antimicrobial activity against non-marine strains when compared to marine strains. Pseudopterogorgia americana, Pseusopterogorgia acerosa, and Pseudoplexuara flexuosa had the highest QS inhibitory effect. Interestingly, Pseudoplexuara porosa extracts stimulated QS activity with a striking 17-fold increase in signal. The stimulation of QS by P. porosa or other elements of the holobiont may encourage colonization or recruitment of specific microbial species. Overall, these results suggest the presence of novel stimulatory QS, inhibitory QS and bactericidal compounds in gorgonian corals. A better understanding of these compounds may reveal insight into coral-microbial ecology and whether a therapeutic potential exists.

Quorum sensing molecules production by nosocomial and soil isolates Acinetobacter baumannii.

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Erdönmez, Demet; Rad, Abbas Yousefi; Aksöz, Nilüfer

2017-12-01

Acinetobacter species remain alive in hospitals on various surfaces, both dry and moist, forming an important source of hospital infections. These bacteria are naturally resistant to many antibiotic classes. Although the role of the quorum sensing system in regulating the virulence factors of Acinetobacter species has not been fully elucidated, it has been reported that they play a role in bacterial biofilm formation. The biofilm formation helps them to survive under unfavorable growth conditions and antimicrobial treatments. It is based on the accumulation of bacterial communication signal molecules in the area. In this study, we compared the bacterial signal molecules of 50 nosocomial Acinetobacter baumannii strain and 20 A. baumannii strain isolated from soil. The signal molecules were detected by the biosensor bacteria (Chromobacterium violaceum 026, Agrobacterium tumefaciens A136, and Agrobacterium tumefaciens NTL1) and their separation was determined by thin-layer chromatography. As a result, it has been found that soil-borne isolates can produce 3-oxo-C8-AHL and C8-AHL, whereas nosocomial-derived isolates can produce long-chain signals such as C10-AHL, C12-AHL, C14-AHL and C16-AHL. According to these results, it is possible to understand that these signal molecules are found in the infection caused by A. baumannii. The inhibition of this signaling molecules in a communication could use to prevent multiple antibiotic resistance of these bacteria.

Reactive oxygen species, essential molecules, during plant-pathogen interactions.

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Camejo, Daymi; Guzmán-Cedeño, Ángel; Moreno, Alexander

2016-06-01

Reactive oxygen species (ROS) are continually generated as a consequence of the normal metabolism in aerobic organisms. Accumulation and release of ROS into cell take place in response to a wide variety of adverse environmental conditions including salt, temperature, cold stresses and pathogen attack, among others. In plants, peroxidases class III, NADPH oxidase (NOX) locates in cell wall and plasma membrane, respectively, may be mainly enzymatic systems involving ROS generation. It is well documented that ROS play a dual role into cells, acting as important signal transduction molecules and as toxic molecules with strong oxidant power, however some aspects related to its function during plant-pathogen interactions remain unclear. This review focuses on the principal enzymatic systems involving ROS generation addressing the role of ROS as signal molecules during plant-pathogen interactions. We described how the chloroplasts, mitochondria and peroxisomes perceive the external stimuli as pathogen invasion, and trigger resistance response using ROS as signal molecule. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

Nonadiabatic Dynamics May Be Probed through Electronic Coherence in Time-Resolved Photoelectron Spectroscopy.

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Bennett, Kochise; Kowalewski, Markus; Mukamel, Shaul

2016-02-09

We present a hierarchy of Fermi golden rules (FGRs) that incorporate strongly coupled electronic/nuclear dynamics in time-resolved photoelectron spectroscopy (TRPES) signals at different levels of theory. Expansion in the joint electronic and nuclear eigenbasis yields the numerically most challenging exact FGR (eFGR). The quasistatic Fermi Golden Rule (qsFGR) neglects nuclear motion during the photoionization process but takes into account electronic coherences as well as populations initially present in the pumped matter as well as those generated internally by coupling between electronic surfaces. The standard semiclassical Fermi Golden Rule (scFGR) neglects the electronic coherences and the nuclear kinetic energy during the ionizing pulse altogether, yielding the classical Condon approximation. The coherence contributions depend on the phase-profile of the ionizing field, allowing coherent control of TRPES signals. The photoelectron spectrum from model systems is simulated using these three levels of theory. The eFGR and the qsFGR show temporal oscillations originating from the electronic or vibrational coherences generated as the nuclear wave packet traverses a conical intersection. These oscillations, which are missed by the scFGR, directly reveal the time-evolving splitting between electronic states of the neutral molecule in the curve-crossing regime.

Analysis of two potential long-distance signaling molecules, LjCLE-RS1/2 and jasmonic acid, in a hypernodulating mutant too much love.

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Magori, Shimpei; Kawaguchi, Masayoshi

2010-04-01

Legume plants tightly control the number and development of root nodules. This is partly regulated by a long-distance signaling known as auto-regulation of nodulation (AON). AON signaling involves at least two potential long-distance signals: root-derived signal and shoot-derived signal. However, their molecular characteristics and the mode of action remain unclear. In our recent study, we isolated a novel Lotus japonicus hypernodulating mutant too much love (tml). Based on several grafting experiments, we concluded that its causative gene TML functions as a receptor of the shoot-derived signal. This finding prompted us to ask how the candidates of the long-distance signal molecules, LjCLE-RS1/2 and jasmonic acid (JA), are affected in tml mutants. Expression analysis revealed that rapid induction of LjCLE-RS1/2 upon rhizobial inoculation is still intact in tml, supporting that TML plays a role in reception of the shoot-derived signal but not in generation of the root-derived signal. Furthermore, physiological analysis showed that JA, a candidate of the shoot-derived signal, can suppress tml hypernodulation. Therefore, contrary to the previous report, JA might not be a component of AON signaling.

TGF-β signaling controls FSHR signaling-reduced ovarian granulosa cell apoptosis through the SMAD4/miR-143 axis.

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Du, Xing; Zhang, Lifan; Li, Xinyu; Pan, Zengxiang; Liu, Honglin; Li, Qifa

2016-11-24

Follicle-stimulating hormone receptor (FSHR) and its intracellular signaling control mammalian follicular development and female infertility. Our previous study showed that FSHR is downregulated during follicular atresia of porcine ovaries. However, its role and regulation in follicular atresia remain unclear. Here, we showed that FSHR knockdown induced porcine granulosa cell (pGC) apoptosis and follicular atresia, and attenuated the levels of intracellular signaling molecules such as PKA, AKT and p-AKT. FSHR was identified as a target of miR-143, a microRNA that was upregulated during porcine follicular atresia. miR-143 enhanced pGC apoptosis by targeting FSHR, and reduced the levels of intracellular signaling molecules. SMAD4, the final molecule in transforming growth factor (TGF)-β signaling, bound to the promoter and induced significant downregulation of miR-143 in vitro and in vivo. Activated TGF-β signaling rescued miR-143-reduced FSHR and intracellular signaling molecules, and miR-143-induced pGC apoptosis. Overall, our findings offer evidence to explain how TGF-β signaling influences and FSHR signaling for regulation of pGC apoptosis and follicular atresia by a specific microRNA, miR-143.

Pseudomonas aeruginosa tolerance to tobramycin, hydrogen peroxide and polymorphonuclear leukocytes is quorum-sensing dependent

DEFF Research Database (Denmark)

Bjarnsholt, Thomas; Jensen, P.O.; Burmolle, M.

2005-01-01

to otherwise lethal doses of antibiotics and are protected from bactericidal activity of polymorphonuclear leukocytes (PMNs). P. aeruginosa controls the expression of many of its virulence factors by means of a cell-cell communication system termed quorum sensing (QS). In the present report it is demonstrated...... that biofilm bacteria in which QS is blocked either by mutation or by administration of QS inhibitory drugs are sensitive to treatment with tobramycin and H2O2, and are readily phagocytosed by PMNs, in contrast to bacteria with functional QS systems. In contrast to the wild-type, QS-deficient biofilms led...... to an immediate respiratory-burst activation of the PMNs in vitro. In vivo QS-deficient mutants provoked a higher degree of inflammation. It is suggested that quorum signals and QS-inhibitory drugs play direct and opposite roles in this process. Consequently, the faster and highly efficient clearance of QS-deficient...

Development and Psychometric Validation of the EDE-QS, a 12 Item Short Form of the Eating Disorder Examination Questionnaire (EDE-Q.

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Nicole Gideon

Full Text Available The aim of this study was to develop and validate a short form of the Eating Disorder Examination Questionnaire (EDE-Q for routine, including session by session, outcome assessment.The current, 28-item version (6.0 of the EDE-Q was completed by 489 individuals aged 18-72 with various eating disorders recruited from three UK specialist eating disorder services. Rasch analysis was carried out on factors identified by means of principal component analysis, which in combination with expert ratings informed the development of an EDE-Q short form. The shortened questionnaire's reliability, validity and sensitivity was assessed based on online data collected from students of a UK university and volunteers with a history of eating disorders recruited from a national eating disorders charity aged 18-74 (N = 559.A 12-item short form, the Eating Disorder Examination Questionnaire Short (EDE-QS was derived. The new measure showed high internal consistency (Cronbach's α = .913 and temporal stability (ICC = .93; p < .001. It was highly correlated with the original EDE-Q (r = .91 for people without ED; r = .82 for people with ED and other measures of eating disorder and comorbid psychopathology. It was sufficiently sensitive to distinguish between people with and without eating disorders.The EDE-QS is a brief, reliable and valid measure of eating disorder symptom severity that performs similarly to the EDE-Q and that lends itself for the use of sessional outcome monitoring in treatment and research.

Adenosine as a signaling molecule in the retina: biochemical and developmental aspects

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ROBERTO PAES-DE-CARVALHO

2002-09-01

Full Text Available The nucleoside adenosine plays an important role as a neurotransmitter or neuromodulator in the central nervous system, including the retina. In the present paper we review compelling evidence showing that adenosine is a signaling molecule in the developing retina. In the chick retina, adenosine transporters are present since early stages of development before the appearance of adenosine A1 receptors modulating dopamine-dependent adenylate cyclase activity or A2 receptors that directly activate the enzyme. Experiments using retinal cell cultures revealed that adenosine is taken up by specific cell populations that when stimulated by depolarization or neurotransmitters such as dopamine or glutamate, release the nucleoside through calcium-dependent transporter-mediated mechanisms. The presence of adenosine in the extracellular medium and the long-term activation of adenosine receptors is able to regulate the survival of retinal neurons and blocks glutamate excitoxicity. Thus, adenosine besides working as a neurotransmitter or neuromodulator in the mature retina, is considered as an important signaling molecule during retinal development having important functions such as regulation of neuronal survival and differentiation.O nucleosídeo adenosina apresenta um importante papel como neurotransmissor ou neuromodulador no sistema nervoso central, inclusive na retina. Neste artigo apresentamos uma revisão das evidências que mostram que a adenosina é uma molécula sinalizadora na retina em desenvolvimento. Na retina de pinto, transportadores de adenosina estão presentes desde estágios precoces do desenvolvimento, antes do aparecimento dos receptores A1 que modulam a atividade adenilato ciclase dependente de dopamina ou dos receptores A2 que ativam diretamente a enzima. Experimentos usando culturas de células de retina revelaram que a adenosina é captada por populações celulares específicas que, quando estimuladas por despolarização ou por

Differential Equations Models to Study Quorum Sensing.

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Pérez-Velázquez, Judith; Hense, Burkhard A

2018-01-01

Mathematical models to study quorum sensing (QS) have become an important tool to explore all aspects of this type of bacterial communication. A wide spectrum of mathematical tools and methods such as dynamical systems, stochastics, and spatial models can be employed. In this chapter, we focus on giving an overview of models consisting of differential equations (DE), which can be used to describe changing quantities, for example, the dynamics of one or more signaling molecule in time and space, often in conjunction with bacterial growth dynamics. The chapter is divided into two sections: ordinary differential equations (ODE) and partial differential equations (PDE) models of QS. Rates of change are represented mathematically by derivatives, i.e., in terms of DE. ODE models allow describing changes in one independent variable, for example, time. PDE models can be used to follow changes in more than one independent variable, for example, time and space. Both types of models often consist of systems (i.e., more than one equation) of equations, such as equations for bacterial growth and autoinducer concentration dynamics. Almost from the onset, mathematical modeling of QS using differential equations has been an interdisciplinary endeavor and many of the works we revised here will be placed into their biological context.

Antioxidant role of glutathione S-transferases: 4-Hydroxynonenal, a key molecule in stress-mediated signaling.

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Singhal, Sharad S; Singh, Sharda P; Singhal, Preeti; Horne, David; Singhal, Jyotsana; Awasthi, Sanjay

2015-12-15

4-Hydroxy-2-trans-nonenal (4HNE), one of the major end products of lipid peroxidation (LPO), has been shown to induce apoptosis in a variety of cell lines. It appears to modulate signaling processes in more than one way because it has been suggested to have a role in signaling for differentiation and proliferation. It has been known that glutathione S-transferases (GSTs) can reduce lipid hydroperoxides through their Se-independent glutathione-peroxidase activity and that these enzymes can also detoxify LPO end-products such as 4HNE. Available evidence from earlier studies together with results of recent studies in our laboratories strongly suggests that LPO products, particularly hydroperoxides and 4HNE, are involved in the mechanisms of stress-mediated signaling and that it can be modulated by the alpha-class GSTs through the regulation of the intracellular concentrations of 4HNE. We demonstrate that 4HNE induced apoptosis in various cell lines is accompanied with c-Jun-N-terminal kinase (JNK) and caspase-3 activation. Cells exposed to mild, transient heat or oxidative stress acquire the capacity to exclude intracellular 4HNE at a faster rate by inducing GSTA4-4 which conjugates 4HNE to glutathione (GSH), and RLIP76 which mediates the ATP-dependent transport of the GSH-conjugate of 4HNE (GS-HNE). The balance between formation and exclusion promotes different cellular processes - higher concentrations of 4HNE promote apoptosis; whereas, lower concentrations promote proliferation. In this article, we provide a brief summary of the cellular effects of 4HNE, followed by a review of its GST-catalyzed detoxification, with an emphasis on the structural attributes that play an important role in the interactions with alpha-class GSTA4-4. Taken together, 4HNE is a key signaling molecule and that GSTs being determinants of its intracellular concentrations, can regulate stress-mediated signaling, are reviewed in this article. Copyright © 2015 Elsevier Inc. All rights

Fluorescent Biosensors Based on Single-Molecule Counting.

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Ma, Fei; Li, Ying; Tang, Bo; Zhang, Chun-Yang

2016-09-20

Biosensors for highly sensitive, selective, and rapid quantification of specific biomolecules make great contributions to biomedical research, especially molecular diagnostics. However, conventional methods for biomolecular assays often suffer from insufficient sensitivity and poor specificity. In some case (e.g., early disease diagnostics), the concentration of target biomolecules is too low to be detected by these routine approaches, and cumbersome procedures are needed to improve the detection sensitivity. Therefore, there is an urgent need for rapid and ultrasensitive analytical tools. In this respect, single-molecule fluorescence approaches may well satisfy the requirement and hold promising potential for the development of ultrasensitive biosensors. Encouragingly, owing to the advances in single-molecule microscopy and spectroscopy over past decades, the detection of single fluorescent molecule comes true, greatly boosting the development of highly sensitive biosensors. By in vitro/in vivo labeling of target biomolecules with proper fluorescent tags, the quantification of certain biomolecule at the single-molecule level is achieved. In comparison with conventional ensemble measurements, single-molecule detection-based analytical methods possess the advantages of ultrahigh sensitivity, good selectivity, rapid analysis time, and low sample consumption. Consequently, single-molecule detection may be potentially employed as an ideal analytical approach to quantify low-abundant biomolecules with rapidity and simplicity. In this Account, we will summarize our efforts for developing a series of ultrasensitive biosensors based on single-molecule counting. Single-molecule counting is a member of single-molecule detection technologies and may be used as a very simple and ultrasensitive method to quantify target molecules by simply counting the individual fluorescent bursts. In the fluorescent sensors, the signals of target biomolecules may be translated to the

Gaseous signalling molecule SO2 via Hippo‑MST pathway to improve myocardial fibrosis of diabetic rats.

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Liu, Maojun; Liu, Shengquan; Tan, Wenting; Tang, Fen; Long, Junrong; Li, Zining; Liang, Biao; Chu, Chun; Yang, Jun

2017-12-01

Recent studies have indicated the existence of an endogenous sulfur dioxide (SO2)‑generating system in the cardiovascular system. The present study aimed to discuss the function and regulatory mechanism of gaseous signal molecule SO2 in inhibiting apoptosis and endoplasmic reticulum stress (ERS) via the Hippo‑MST signaling pathway to improve myocardial fibrosis of diabetic rats. A total of 40 male Sprague‑Dawley rats were randomly divided into four groups (10 rats per group): Normal control group (control group), diabetic rats group [streptozotocin (STZ) group], SO2 intervention group (STZ+SO2 group) and diabetes mellitus rats treated with L‑Aspartic acid β‑hydroxamate (HDX) group (HDX group). Diabetic rats models were established by intra‑peritoneal injection of STZ (40 mg/kg) Following model establishment, intra‑peritoneal injection of Na2SO3/NaHSO3 solution (0.54 mmol/kg) was administered in the STZ+SO2 group, and HDX solution (25 mg/kg/week) was administered in the HDX group. A total of 4 weeks later, echocardiography was performed to evaluate rats' cardiac function; Masson staining, terminal deoxynucleotidyl transferase dUTP nick end labeling staining and transmission electron microscopy examinations were performed to observe myocardial morphological changes. ELISA was employed to determine the SO2 content. Western blot analysis was performed to detect the expression of proteins associated with apoptosis, ERS and the Hippo‑MST signalling pathway. Compared with the control group, the STZ group and HDX group had a disordered arrangement of myocardial cells with apparent myocardial fibrosis, and echocardiography indicated that the cardiac function was lowered, there was an obvious increase of apoptosis in myocardial tissue, the expression levels of apoptosis‑associated protein B‑cell lymphoma associated protein X, caspase‑3 and caspase‑9 were upregulated, and Bcl‑2 expression was downregulated. The expression of ERS and Hippo�

Identification of potential genetic components involved in the deviant quorum-sensing signaling pathways of Burkholderia glumae through a functional genomics approach

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Ruoxi eChen

2015-03-01

Full Text Available Burkholderia glumae is the chief causal agent for bacterial panicle blight of rice. The acyl-homoserine lactone (AHL-mediated quorum-sensing (QS system dependent on a pair of luxI and luxR homologs, tofI and tofR, is the primary cell-to-cell signaling mechanism determining the virulence of this bacterium. Production of toxoflavin, a major virulence factor of B. glumae, is known to be dependent on the tofI/tofR QS system. In our previous study, however, it was observed that B. glumae mutants defective in tofI or tofR produced toxoflavin if they grew on the surface of a solid medium, suggesting that alternative signaling pathways independent of tofI or tofR are activated in that growth condition for the production of toxoflavin. In this study, potential genetic components involved in the tofI- and tofR-independent signaling pathways for toxoflavin production were sought through screening random mini-Tn5 mutants of B. glumae to better understand the intercellular signaling pathways of this pathogen. Fifteen and three genes were initially identified as the potential genetic elements of the tofI- and tofR-independent pathways, respectively. Especially, the ORF (bglu_2g06320 divergently transcribed from toxJ, which encodes an orphan LuxR protein and controls toxoflavin biosynthesis, was newly identified in this study as a gene required for the tofR-independent toxoflavin production and named as toxK. Among those genes, flhD, dgcB, and wyzB were further studied to validate their functions in the tofI-independent toxoflavin production, and similar studies were also conducted with qsmR and toxK for their functions in the tofR-independent toxoflavin production. This work provides a foundation for future comprehensive studies of the intercellular signaling systems of B. glumae and other related pathogenic bacteria.

Constitutive MHC class I molecules negatively regulate TLR-triggered inflammatory responses via the Fps-SHP-2 pathway.

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Xu, Sheng; Liu, Xingguang; Bao, Yan; Zhu, Xuhui; Han, Chaofeng; Zhang, Peng; Zhang, Xuemin; Li, Weihua; Cao, Xuetao

2012-04-22

The molecular mechanisms that fine-tune Toll-like receptor (TLR)-triggered innate inflammatory responses remain to be fully elucidated. Major histocompatibility complex (MHC) molecules can mediate reverse signaling and have nonclassical functions. Here we found that constitutively expressed membrane MHC class I molecules attenuated TLR-triggered innate inflammatory responses via reverse signaling, which protected mice from sepsis. The intracellular domain of MHC class I molecules was phosphorylated by the kinase Src after TLR activation, then the tyrosine kinase Fps was recruited via its Src homology 2 domain to phosphorylated MHC class I molecules. This led to enhanced Fps activity and recruitment of the phosphatase SHP-2, which interfered with TLR signaling mediated by the signaling molecule TRAF6. Thus, constitutive MHC class I molecules engage in crosstalk with TLR signaling via the Fps-SHP-2 pathway and control TLR-triggered innate inflammatory responses.

Modulation of opiate-related signaling molecules in morphine-dependent conditioned behavior: conditioned place preference to morphine induces CREB phosphorylation.

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Morón, José A; Gullapalli, Srinivas; Taylor, Chirisse; Gupta, Achla; Gomes, Ivone; Devi, Lakshmi A

2010-03-01

Opiate addiction is a chronic, relapsing behavioral disorder where learned associations that develop between the abused opiate and the environment in which it is consumed are brought about through Pavlovian (classical) conditioning processes. However, the signaling mechanisms/pathways regulating the mechanisms that underlie the responses to opiate-associated cues or the development of sensitization as a consequence of repeated context-independent administration of opiates are unknown. In this study we examined the phosphorylation levels of various classic signaling molecules in brain regions implicated in addictive behaviors after acute and repeated morphine administration. An unbiased place conditioning protocol was used to examine changes in phosphorylation that are associated with (1) the expression of the rewarding effects of morphine and (2) the sensitization that develops to this effect. We also examined the effects of a delta-receptor antagonist on morphine-induced conditioned behavior and on the phosphorylation of classic signaling molecules in view of data showing that blockade of delta-opioid receptor (deltaOR) prevents the development of sensitization to the rewarding effects of morphine. We find that CREB phosphorylation is specifically induced upon the expression of a sensitized response to morphine-induced conditioned behavior in brain areas related to memory consolidation, such as the hippocampus and cortex. A similar effect is also observed, albeit to a lesser extent, in the case of the GluR1 subunit of AMPA glutamate receptor. These increases in the phosphorylation levels of CREB and pGluR1 are significantly blocked by pretreatment with a deltaOR antagonist. These results indicate a critical role for phospho-CREB, AMPA, and deltaOR activities in mediating the expression of a sensitized response to morphine-dependent conditioned behavior.

Deletion of the signalling molecule synthase ScbA has pleiotropic effects on secondary metabolite biosynthesis, morphological differentiation and primary metabolism in Streptomyces coelicolor A3(2)

NARCIS (Netherlands)

D'Alia, Davide; Eggle, D.; Nieselt, K.; Hu, W.-S.; Breitling, R.; Takano, E.

2011-01-01

Streptomycetes have high biotechnological relevance as producers of diverse metabolites widely used in medical and agricultural applications. The biosynthesis of these metabolites is controlled by signalling molecules, gamma-butyrolactones, that act as bacterial hormones. In Streptomyces coelicolor,

ω-Hydroxyemodin Limits Staphylococcus aureus Quorum Sensing-Mediated Pathogenesis and Inflammation

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Daly, Seth M.; Elmore, Bradley O.; Kavanaugh, Jeffrey S.; Triplett, Kathleen D.; Figueroa, Mario; Raja, Huzefa A.; El-Elimat, Tamam; Crosby, Heidi A.; Femling, Jon K.; Cech, Nadja B.; Horswill, Alexander R.; Oberlies, Nicholas H.

2015-01-01

Antibiotic-resistant pathogens are a global health threat. Small molecules that inhibit bacterial virulence have been suggested as alternatives or adjuncts to conventional antibiotics, as they may limit pathogenesis and increase bacterial susceptibility to host killing. Staphylococcus aureus is a major cause of invasive skin and soft tissue infections (SSTIs) in both the hospital and community settings, and it is also becoming increasingly antibiotic resistant. Quorum sensing (QS) mediated by the accessory gene regulator (agr) controls virulence factor production essential for causing SSTIs. We recently identified ω-hydroxyemodin (OHM), a polyhydroxyanthraquinone isolated from solid-phase cultures of Penicillium restrictum, as a suppressor of QS and a compound sought for the further characterization of the mechanism of action. At concentrations that are nontoxic to eukaryotic cells and subinhibitory to bacterial growth, OHM prevented agr signaling by all four S. aureus agr alleles. OHM inhibited QS by direct binding to AgrA, the response regulator encoded by the agr operon, preventing the interaction of AgrA with the agr P2 promoter. Importantly, OHM was efficacious in a mouse model of S. aureus SSTI. Decreased dermonecrosis with OHM treatment was associated with enhanced bacterial clearance and reductions in inflammatory cytokine transcription and expression at the site of infection. Furthermore, OHM treatment enhanced the immune cell killing of S. aureus in vitro in an agr-dependent manner. These data suggest that bacterial disarmament through the suppression of S. aureus QS may bolster the host innate immune response and limit inflammation. PMID:25645827

Effect of the synthetic cannabinoid HU-210 on quorum sensing and on the production of quorum sensing-mediated virulence factors by Vibrio harveyi.

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Soni, Divya; Smoum, Reem; Breuer, Aviva; Mechoulam, Raphael; Steinberg, Doron

2015-08-12

Bacterial populations communicate through the cell density-dependent mechanism of quorum sensing (QS). Vibrio harveyi, one of the best studied model organisms for QS, was used to explore effects of the synthetic cannabinoid HU-210 on QS and different QS-regulated physiological processes in bacteria. Analysis of QS-regulated bioluminescence in wild-type and mutant strains of V. harveyi revealed that HU-210 affects the autoinducer-2 (AI-2) pathway, one of three known QS cascades of V. harveyi. Furthermore, QS-mediated biofilm formation and swimming motility in the mutant strain BB152 (AI-1(-), AI-2(+)) were significantly reduced in the presence of HU-210. HU-210 inhibited QS-mediated virulence factor production without any inhibitory effect on bacterial growth. It also alters the expression of several genes, which are regulated by QS, specifically downregulating the genes of the AI-2 QS cascade. First evidence is being provided for interference of bacterial signal-transduction systems by a synthetic cannabinoid. The effect of HU-210 was specific to the AI-2 cascade in V. harveyi. AI-2 is known as a "universal autoinducer" and interference with its activity opens a broad spectrum of applications for synthetic cannabinoids in future research as a potential anti-QS agent.

Nitrogen modulation of legume root architecture signalling pathways involves phytohormones and small regulatory molecules

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Nadiatul Akmal Mohd-Radzman

2013-10-01

Full Text Available Nitrogen, particularly nitrate is an important yield determinant for crops. However, current agricultural practice with excessive fertilizer usage has detrimental effects on the environment. Therefore, legumes have been suggested as a sustainable alternative for replenishing soil nitrogen. Legumes can uniquely form nitrogen-fixing nodules through symbiotic interaction with specialized soil bacteria. Legumes possess a highly plastic root system which modulates its architecture according to the nitrogen availability in the soil. Understanding how legumes regulate root development in response to nitrogen availability is an important step to improving root architecture. The nitrogen-mediated root development pathway starts with sensing soil nitrogen level followed by subsequent signal transduction pathways involving phytohormones, microRNAs and regulatory peptides that collectively modulate the growth and shape of the root system. This review focuses on the current understanding of nitrogen-mediated legume root architecture including local and systemic regulations by different N-sources and the modulations by phytohormones and small regulatory molecules.

Nitrogen modulation of legume root architecture signaling pathways involves phytohormones and small regulatory molecules.

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Mohd-Radzman, Nadiatul A; Djordjevic, Michael A; Imin, Nijat

2013-10-01

Nitrogen, particularly nitrate is an important yield determinant for crops. However, current agricultural practice with excessive fertilizer usage has detrimental effects on the environment. Therefore, legumes have been suggested as a sustainable alternative for replenishing soil nitrogen. Legumes can uniquely form nitrogen-fixing nodules through symbiotic interaction with specialized soil bacteria. Legumes possess a highly plastic root system which modulates its architecture according to the nitrogen availability in the soil. Understanding how legumes regulate root development in response to nitrogen availability is an important step to improving root architecture. The nitrogen-mediated root development pathway starts with sensing soil nitrogen level followed by subsequent signal transduction pathways involving phytohormones, microRNAs and regulatory peptides that collectively modulate the growth and shape of the root system. This review focuses on the current understanding of nitrogen-mediated legume root architecture including local and systemic regulations by different N-sources and the modulations by phytohormones and small regulatory molecules.

Inhibition of TLR2 signaling by small molecule inhibitors targeting a pocket within the TLR2 TIR domain

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Mistry, Pragnesh; Laird, Michelle H. W.; Schwarz, Ryan S.; Greene, Shannon; Dyson, Tristan; Snyder, Greg A.; Xiao, Tsan Sam; Chauhan, Jay; Fletcher, Steven; Toshchakov, Vladimir Y.; MacKerell, Alexander D.; Vogel, Stefanie N.

2015-01-01

Toll-like receptor (TLR) signaling is initiated by dimerization of intracellular Toll/IL-1 receptor resistance (TIR) domains. For all TLRs except TLR3, recruitment of the adapter, myeloid differentiation primary response gene 88 (MyD88), to TLR TIR domains results in downstream signaling culminating in proinflammatory cytokine production. Therefore, blocking TLR TIR dimerization may ameliorate TLR2-mediated hyperinflammatory states. The BB loop within the TLR TIR domain is critical for mediating certain protein–protein interactions. Examination of the human TLR2 TIR domain crystal structure revealed a pocket adjacent to the highly conserved P681 and G682 BB loop residues. Using computer-aided drug design (CADD), we sought to identify a small molecule inhibitor(s) that would fit within this pocket and potentially disrupt TLR2 signaling. In silico screening identified 149 compounds and 20 US Food and Drug Administration-approved drugs based on their predicted ability to bind in the BB loop pocket. These compounds were screened in HEK293T-TLR2 transfectants for the ability to inhibit TLR2-mediated IL-8 mRNA. C16H15NO4 (C29) was identified as a potential TLR2 inhibitor. C29, and its derivative, ortho-vanillin (o-vanillin), inhibited TLR2/1 and TLR2/6 signaling induced by synthetic and bacterial TLR2 agonists in human HEK-TLR2 and THP-1 cells, but only TLR2/1 signaling in murine macrophages. C29 failed to inhibit signaling induced by other TLR agonists and TNF-α. Mutagenesis of BB loop pocket residues revealed an indispensable role for TLR2/1, but not TLR2/6, signaling, suggesting divergent roles. Mice treated with o-vanillin exhibited reduced TLR2-induced inflammation. Our data provide proof of principle that targeting the BB loop pocket is an effective approach for identification of TLR2 signaling inhibitors. PMID:25870276

Antioxidant role of glutathione S-transferases: 4-Hydroxynonenal, a key molecule in stress-mediated signaling

International Nuclear Information System (INIS)

Singhal, Sharad S.; Singh, Sharda P.; Singhal, Preeti; Horne, David; Singhal, Jyotsana; Awasthi, Sanjay

2015-01-01

4-Hydroxy-2-trans-nonenal (4HNE), one of the major end products of lipid peroxidation (LPO), has been shown to induce apoptosis in a variety of cell lines. It appears to modulate signaling processes in more than one way because it has been suggested to have a role in signaling for differentiation and proliferation. It has been known that glutathione S-transferases (GSTs) can reduce lipid hydroperoxides through their Se-independent glutathione-peroxidase activity and that these enzymes can also detoxify LPO end-products such as 4HNE. Available evidence from earlier studies together with results of recent studies in our laboratories strongly suggests that LPO products, particularly hydroperoxides and 4HNE, are involved in the mechanisms of stress-mediated signaling and that it can be modulated by the alpha-class GSTs through the regulation of the intracellular concentrations of 4HNE. We demonstrate that 4HNE induced apoptosis in various cell lines is accompanied with c-Jun-N-terminal kinase (JNK) and caspase-3 activation. Cells exposed to mild, transient heat or oxidative stress acquire the capacity to exclude intracellular 4HNE at a faster rate by inducing GSTA4-4 which conjugates 4HNE to glutathione (GSH), and RLIP76 which mediates the ATP-dependent transport of the GSH-conjugate of 4HNE (GS-HNE). The balance between formation and exclusion promotes different cellular processes — higher concentrations of 4HNE promote apoptosis; whereas, lower concentrations promote proliferation. In this article, we provide a brief summary of the cellular effects of 4HNE, followed by a review of its GST-catalyzed detoxification, with an emphasis on the structural attributes that play an important role in the interactions with alpha-class GSTA4-4. Taken together, 4HNE is a key signaling molecule and that GSTs being determinants of its intracellular concentrations, can regulate stress-mediated signaling, are reviewed in this article. - Highlights: • GSTs are the major

Expression of SMAD signal transduction molecules in the pancreas

DEFF Research Database (Denmark)

Brorson, Michael; Hougaard, D.; Nielsen, Jens Høiriis

2001-01-01

Members of the TGF-beta superfamily of cytokines have been implicated in pancreatic cancer, pancreatitis and in regulation and differentiation of pancreatic endocrine and exocrine cells. Different TGF-beta members signal through phosphorylation of different signal transduction proteins, which eve...

Cellular signalling properties in microcircuits

DEFF Research Database (Denmark)

Toledo-Rodriguez, Maria; El Manira, Abdeljabbar; Wallén, Peter

2005-01-01

Molecules and cells are the signalling elements in microcircuits. Recent studies have uncovered bewildering diversity in postsynaptic signalling properties in all areas of the vertebrate nervous system. Major effort is now being invested in establishing the specialized signalling properties...

Generalized extracellular molecule sensor platform for programming cellular behavior.

Science.gov (United States)

Scheller, Leo; Strittmatter, Tobias; Fuchs, David; Bojar, Daniel; Fussenegger, Martin

2018-04-23

Strategies for expanding the sensor space of designer receptors are urgently needed to tailor cell-based therapies to respond to any type of medically relevant molecules. Here, we describe a universal approach to designing receptor scaffolds that enables antibody-specific molecular input to activate JAK/STAT, MAPK, PLCG or PI3K/Akt signaling rewired to transgene expression driven by synthetic promoters. To demonstrate its scope, we equipped the GEMS (generalized extracellular molecule sensor) platform with antibody fragments targeting a synthetic azo dye, nicotine, a peptide tag and the PSA (prostate-specific antigen) biomarker, thereby covering inputs ranging from small molecules to proteins. These four GEMS devices provided robust signaling and transgene expression with high signal-to-noise ratios in response to their specific ligands. The sensitivity of the nicotine- and PSA-specific GEMS devices matched the clinically relevant concentration ranges, and PSA-specific GEMS were able to detect pathological PSA levels in the serum of patients diagnosed with prostate cancer.

Baicalin inhibits biofilm formation, attenuates the quorum sensing-controlled virulence and enhances Pseudomonas aeruginosa clearance in a mouse peritoneal implant infection model.

Directory of Open Access Journals (Sweden)

Jing Luo

Full Text Available The quorum sensing (QS circuit plays a role in the precise regulation of genes controlling virulence factors and biofilm formation in Pseudomonas aeruginosa. QS-controlled biofilm formation by Pseudomonas aeruginosa in clinical settings has remained controversial due to emerging drug resistance; therefore, screening diverse compounds for anti-biofilm or anti-QS activities is important. This study demonstrates the ability of sub-minimum inhibitory concentrations (sub-MICs of baicalin, an active natural compound extracted from the traditional Chinese medicinal Scutellaria baicalensis, to inhibit the formation of Pseudomonas aeruginosa biofilms and enhance the bactericidal effects of various conventional antibiotics in vitro. In addition, baicalin exerted dose-dependent inhibitory effects on virulence phenotypes (LasA protease, LasB elastase, pyocyanin, rhamnolipid, motilities and exotoxin A regulated by QS in Pseudomonas aeruginosa. Moreover, the expression levels of QS-regulatory genes, including lasI, lasR, rhlI, rhlR, pqsR and pqsA, were repressed after sub-MIC baicalin treatment, resulting in significant decreases in the QS signaling molecules 3-oxo-C12-HSL and C4-HSL, confirming the ability of baicalin-mediated QS inhibition to alter gene and protein expression. In vivo experiments indicated that baicalin treatment reduces Pseudomonas aeruginosa pathogenicity in Caenorhabditis elegans. Greater worm survival in the baicalin-treated group manifested as an increase in the LT50 from 24 to 96 h. In a mouse peritoneal implant infection model, baicalin treatment enhanced the clearance of Pseudomonas aeruginosa from the implants of mice infected with Pseudomonas aeruginosa compared with the control group. Moreover, the combination of baicalin and antibiotics significantly reduced the numbers of colony-forming units in the implants to a significantly greater degree than antibiotic treatment alone. Pathological and histological analyses revealed

Lipid rafts generate digital-like signal transduction in cell plasma membranes.

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Suzuki, Kenichi G N

2012-06-01

Lipid rafts are meso-scale (5-200 nm) cell membrane domains where signaling molecules assemble and function. However, due to their dynamic nature, it has been difficult to unravel the mechanism of signal transduction in lipid rafts. Recent advanced imaging techniques have revealed that signaling molecules are frequently, but transiently, recruited to rafts with the aid of protein-protein, protein-lipid, and/or lipid-lipid interactions. Individual signaling molecules within the raft are activated only for a short period of time. Immobilization of signaling molecules by cytoskeletal actin filaments and scaffold proteins may facilitate more efficient signal transmission from rafts. In this review, current opinions of how the transient nature of molecular interactions in rafts generates digital-like signal transduction in cell membranes, and the benefits this phenomenon provides, are discussed. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Adaptive Significance of Quorum Sensing-Dependent Regulation of Rhamnolipids by Integration of Growth Rate in Burkholderia glumae: A Trade-Off between Survival and Efficiency.

Science.gov (United States)

Nickzad, Arvin; Déziel, Eric

2016-01-01

Quorum sensing (QS) is a cell density-dependent mechanism which enables a population of bacteria to coordinate cooperative behaviors in response to the accumulation of self-produced autoinducer signals in their local environment. An emerging framework is that the adaptive significance of QS in the regulation of production of costly extracellular metabolites ("public goods") is to maintain the homeostasis of cooperation. We investigated this model using the phytopathogenic bacterium Burkholderia glumae, which we have previously demonstrated uses QS to regulate the production of rhamnolipids, extracellular surface-active glycolipids promoting the social behavior called "swarming motility." Using mass spectrometric quantification and chromosomal lux-based gene expression, we made the unexpected finding that when unrestricted nutrient resources are provided, production of rhamnolipids is carried out completely independently of QS regulation. This is a unique observation among known QS-controlled factors in bacteria. On the other hand, under nutrient-limited conditions, QS then becomes the main regulating mechanism, significantly enhancing the specific rhamnolipids yield. Accordingly, decreasing nutrient concentrations amplifies rhamnolipid biosynthesis gene expression, revealing a system where QS-dependent regulation is specifically triggered by the growth rate of the population, rather than by its cell density. Furthermore, a gradual increase in QS signal specific concentration upon decrease of specific growth rate suggests a reduction in quorum threshold, which reflects an increase in cellular demand for production of QS-dependent target gene product at low density populations. Integration of growth rate with QS as a decision-making mechanism for biosynthesis of costly metabolites, such as rhamnolipids, could serve to assess the demand and timing for expanding the carrying capacity of a population through spatial expansion mechanisms, such as swarming motility, thus

Molecule-binding dependent assembly of split aptamer and γ-cyclodextrin: A sensitive excimer signaling approach for aptamer biosensors

International Nuclear Information System (INIS)

Jin, Fen; Lian, Yan; Li, Jishan; Zheng, Jing; Hu, Yaping; Liu, Jinhua; Huang, Jin; Yang, Ronghua

2013-01-01

Graphical abstract: Adenosine-binding aptamer was splitted into two fragments P2 and P3 which labeled pyrene molecules, mainly produce monomer signal. γ-CD cavity brings P2 and P3 in close proximity, allowing for weak excimer emission. In the presence of target, P2 and P3 are expected to bind ATP and form an aptamer/target complex, leads to large increase of the pyrene excimer fluorescence. -- Highlights: •We assembled split aptamer and γ-cyclodextrin fluorescence biosensors for ATP detection. •The biosensor increased quantum yield and emission lifetime of the excimer. •Time-resolved fluorescence is effective for ATP assay in complicated environment. -- Abstract: A highly sensitive and selective fluorescence aptamer biosensors for the determination of adenosine triphosphate (ATP) was developed. Binding of a target with splitting aptamers labeled with pyrene molecules form stable pyrene dimer in the γ-cyclodextrin (γ-CD) cavity, yielding a strong excimer emission. We have found that inclusion of pyrene dimer in γ-cyclodextrin cavity not only exhibits additive increases in quantum yield and emission lifetime of the excimer, but also facilitates target-induced fusion of the splitting aptamers to form the aptamer/target complex. As proof-of-principle, the approach was applied to fluorescence detection of adenosine triphosphate. With an anti-ATP aptamer, the approach exhibits excimer fluorescence response toward ATP with a maximum signal-to-background ratio of 32.1 and remarkably low detection limit of 80 nM ATP in buffer solution. Moreover, due to the additive fluorescence lifetime of excimer induced by γ-cyclodextrin, time-resolved measurements could be conveniently used to detect as low as 0.5 μM ATP in blood serum quantitatively

Four-Wave Mixing Spectroscopy of Quantum Dot Molecules

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Sitek, A.; Machnikowski, P.

2007-08-01

We study theoretically the nonlinear four-wave mixing response of an ensemble of coupled pairs of quantum dots (quantum dot molecules). We discuss the shape of the echo signal depending on the parameters of the ensemble: the statistics of transition energies and the degree of size correlations between the dots forming the molecules.

Heme as a danger molecule in pathogen recognition.

Science.gov (United States)

Wegiel, Barbara; Hauser, Carl J; Otterbein, Leo E

2015-12-01

Appropriate control of redox mechanisms are critical for and effective innate immune response, which employs multiple cell types, receptors and molecules that recognize danger signals when they reach the host. Recognition of pathogen-associated pattern molecules (PAMPs) is a fundamental host survival mechanism for efficient elimination of invading pathogens and resolution of the infection and inflammation. In addition to PAMPs, eukaryotic cells contain a plethora of intracellular molecules that are normally secured within the confines of the plasma membrane, but if liberated and encountered in the extracellular milieu can provoke rapid cell activation. These are known as Alarmins or Danger-Associated Molecular Patterns (DAMPs) and can be released actively by cells or passively as a result of sterile cellular injury after trauma, ischemia, or toxin-induced cell rupture. Both PAMPs and DAMPs are recognized by a series of cognate receptors that increase the generation of free radicals and activate specific signaling pathways that result in regulation of a variety of stress response, redox sensitive genes. Multiple mediators released, as cells die include, but are not limited to ATP, hydrogen peroxide, heme, formyl peptides, DNA or mitochondria provide the second signal to amplify immune responses. In this review, we will focus on how sterile and infective stimuli activate the stress response gene heme oxygenase-1 (Hmox1, HO-1), a master gene critical to an appropriate host response that is now recognized as one with enormous therapeutic potential. HO-1 gene expression is regulated in large part by redox-sensitive proteins including but not limited to nrf2. Both PAMPs and DAMPs increase the activation of nrf2 and HO-1. Heme is a powerful pro-oxidant and as such should be qualified as a DAMP. With its degradation by HO-1a molecule of carbon monoxide (CO) is generated that in turn serves as a bioactive signaling molecule. PAMPs such as bacterial endotoxin activate HO-1

Single-molecule imaging and manipulation of biomolecular machines and systems.

Science.gov (United States)

Iino, Ryota; Iida, Tatsuya; Nakamura, Akihiko; Saita, Ei-Ichiro; You, Huijuan; Sako, Yasushi

2018-02-01

Biological molecular machines support various activities and behaviors of cells, such as energy production, signal transduction, growth, differentiation, and migration. We provide an overview of single-molecule imaging methods involving both small and large probes used to monitor the dynamic motions of molecular machines in vitro (purified proteins) and in living cells, and single-molecule manipulation methods used to measure the forces, mechanical properties and responses of biomolecules. We also introduce several examples of single-molecule analysis, focusing primarily on motor proteins and signal transduction systems. Single-molecule analysis is a powerful approach to unveil the operational mechanisms both of individual molecular machines and of systems consisting of many molecular machines. Quantitative, high-resolution single-molecule analyses of biomolecular systems at the various hierarchies of life will help to answer our fundamental question: "What is life?" This article is part of a Special Issue entitled "Biophysical Exploration of Dynamical Ordering of Biomolecular Systems" edited by Dr. Koichi Kato. Copyright © 2017 Elsevier B.V. All rights reserved.

The RNA chaperone, Hfq, controls two luxR-type regulators and plays a key role in pathogenesis and production of antibiotics in Serratia sp. ATCC 39006.

Science.gov (United States)

Wilf, Nabil M; Williamson, Neil R; Ramsay, Joshua P; Poulter, Simon; Bandyra, Kasia J; Salmond, George P C

2011-10-01

Serratia sp. ATCC 39006 (S39006) is a Gram-negative bacterium that is virulent in plant (potato) and animal (Caenorhabditis elegans) models. It produces two secondary metabolite antibiotics, a prodigiosin and a carbapenem, and the exoenzymes, pectate lyase and cellulase. A complex regulatory network that includes quorum sensing (QS) controls production of prodigiosin. While many aspects of the regulation of the metabolites and exoenzymes are well understood, the potential role in this network of the RNA chaperone Hfq and dependent small regulatory RNAs has not been characterized. Hfq is an RNA chaperone involved in post-transcriptional regulation that plays a key role in stress response and virulence in diverse bacterial species. To explore whether Hfq-dependent processes might contribute to the regulation of antibiotic production we constructed an S39006 Δhfq mutant. Production of prodigiosin and carbapenem was abolished in this mutant strain, while production of the QS signalling molecule, butanoyl homoserine lactone (BHL), was unaffected. Using transcriptional fusions, we found that Hfq regulates the QS response regulators, SmaR and CarR. Additionally, exoenzyme production and swimming motility were decreased in a Δhfq mutant, and virulence was attenuated in potato and C. elegans models. These results suggest that an Hfq-dependent pathway is involved in the regulation of virulence and secondary metabolite production in S39006. © 2011 Society for Applied Microbiology and Blackwell Publishing Ltd.

Investigation of N-acyl homoserine lactone (AHL) molecule production in Gram-negative bacteria isolated from cooling tower water and biofilm samples.

Science.gov (United States)

Haslan, Ezgi; Kimiran-Erdem, Ayten

2013-09-01

In this study, 99 Gram-negative rod bacteria were isolated from cooling tower water, and biofilm samples were examined for cell-to-cell signaling systems, N-acyl homoserine lactone (AHL) signal molecule types, and biofilm formation capacity. Four of 39 (10 %) strains isolated from water samples and 14 of 60 (23 %) strains isolated from biofilm samples were found to be producing a variety of AHL signal molecules. It was determined that the AHL signal molecule production ability and the biofilm formation capacity of sessile bacteria is higher than planktonic bacteria, and there was a statistically significant difference between the AHL signal molecule production of these two groups (p cooling tower water and biofilm samples produced different types of AHL signal molecules and that there were different types of AHL signal molecules in an AHL extract of bacteria. In the present study, it was observed that different isolates of the same strains did not produce the same AHLs or did not produce AHL molecules, and bacteria known as AHL producers did not produce AHL. These findings suggest that detection of signal molecules in bacteria isolated from cooling towers may contribute to prevention of biofilm formation, elimination of communication among bacteria in water systems, and blockage of quorum-sensing controlled virulence of these bacteria.

Role of the DIP Molecules in DCC Signaling

Science.gov (United States)

1999-09-01

to policies of applicable Federal Law 45 CFR 46. N/A In conducting research utilizing recombinant DNA technology , the investigator(s) adhered to...for 1 h, then with 0.1 mg/ml of proteinase K, 0.1% SDS at 50’C Ihle, 1995; Fraser and Evan, 1996). These molecules overnight. Samples were extracted ...incubated with 20 yg/ml of anti-DCC antibody diluted in PBS-0.1% saponin for 1 h, washed with PBS, blocked Western blotting with 5% normal donkey serum for 1

Expression of GABA signaling molecules KCC2, NKCC1, and GAD1 in cortical development and schizophrenia.

Science.gov (United States)

Hyde, Thomas M; Lipska, Barbara K; Ali, Towhid; Mathew, Shiny V; Law, Amanda J; Metitiri, Ochuko E; Straub, Richard E; Ye, Tianzhang; Colantuoni, Carlo; Herman, Mary M; Bigelow, Llewellyn B; Weinberger, Daniel R; Kleinman, Joel E

2011-07-27

GABA signaling molecules are critical for both human brain development and the pathophysiology of schizophrenia. We examined the expression of transcripts derived from three genes related to GABA signaling [GAD1 (GAD67 and GAD25), SLC12A2 (NKCC1), and SLC12A5 (KCC2)] in the prefrontal cortex (PFC) and hippocampal formation of a large cohort of nonpsychiatric control human brains (n = 240) across the lifespan (from fetal week 14 to 80 years) and in patients with schizophrenia (n = 30-31), using quantitative RT-PCR. We also examined whether a schizophrenia risk-associated promoter SNP in GAD1 (rs3749034) is related to expression of these transcripts. Our studies revealed that development and maturation of both the PFC and hippocampal formation are characterized by progressive switches in expression from GAD25 to GAD67 and from NKCC1 to KCC2. Previous studies have demonstrated that the former leads to GABA synthesis, and the latter leads to switching from excitatory to inhibitory neurotransmission. In the hippocampal formation, GAD25/GAD67 and NKCC1/KCC2 ratios are increased in patients with schizophrenia, reflecting a potentially immature GABA physiology. Remarkably, GAD25/GAD67 and NKCC1/KCC2 expression ratios are associated with rs3749034 genotype, with risk alleles again predicting a relatively less mature pattern. These findings suggest that abnormalities in GABA signaling critical to brain development contribute to genetic risk for schizophrenia.

Plant natriuretic peptides are apoplastic and paracrine stress response molecules

KAUST Repository

Wang, Yuhua; Gehring, Christoph A; Irving, Helen R.

2011-01-01

plant stress responses and that, much like in animals, peptide signaling molecules can create diverse and modular signals essential for growth, development and defense under rapidly changing environmental conditions. © 2011 The Author.

Hydrogen sulfide in plants: from dissipation of excess sulfur to signaling molecule.

Science.gov (United States)

Calderwood, Alexander; Kopriva, Stanislav

2014-09-15

Sulfur is essential in all organisms for the synthesis of amino acids cysteine and methionine and as an active component of numerous co-factors and prosthetic groups. However, only plants, algae, fungi, and some prokaryotes are capable of using the abundant inorganic source of sulfur, sulfate. Plants take sulfate up, reduce it, and assimilate into organic compounds with cysteine being the first product of the pathway and a donor of reduced sulfur for synthesis of other S-containing compounds. Cysteine is formed in a reaction between sulfide, derived from reduction of sulfite and an activated amino acid acceptor, O-acetylserine. Sulfide is thus an important intermediate in sulfur metabolism, but numerous other functions in plants has been revealed. Hydrogen sulfide can serve as an alternative source of sulfur for plants, which may be significant in anaerobic conditions of waterlogged soils. On the other hand, emissions of hydrogen sulfide have been detected from many plant species. Since the amount of H2S discharged correlated with sulfate supply to the plants, the emissions were considered a mechanism for dissipation of excess sulfur. Significant hydrogen sulfide emissions were also observed in plants infected with pathogens, particularly with fungi. H2S thus seems to be part of the widely discussed sulfur-induced-resistance/sulfur-enhanced-defense. Recently, however, more evidence has emerged for a role for H2S in regulation and signaling. Sulfide stabilizes the cysteine synthase complex, increasing so the synthesis of its acceptor O-acetylserine. H2S has been implicating in regulation of plant stress response, particularly draught stress. There are more and more examples of processes regulated by H2S in plants being discovered, and hydrogen sulfide is emerging as an important signaling molecule, similar to its role in the animal and human world. How similar the functions, and homeostasis of H2S are in these diverse organisms, however, remains to be elucidated

Identification of small molecule compounds that inhibit the HIF-1 signaling pathway

Directory of Open Access Journals (Sweden)

Sun Yi

2009-12-01

Full Text Available Abstract Background Hypoxia-inducible factor-1 (HIF-1 is the major hypoxia-regulated transcription factor that regulates cellular responses to low oxygen environments. HIF-1 is composed of two subunits: hypoxia-inducible HIF-1α and constitutively-expressed HIF-1β. During hypoxic conditions, HIF-1α heterodimerizes with HIF-1β and translocates to the nucleus where the HIF-1 complex binds to the hypoxia-response element (HRE and activates expression of target genes implicated in cell growth and survival. HIF-1α protein expression is elevated in many solid tumors, including those of the cervix and brain, where cells that are the greatest distance from blood vessels, and therefore the most hypoxic, express the highest levels of HIF-1α. Therapeutic blockade of the HIF-1 signaling pathway in cancer cells therefore provides an attractive strategy for development of anticancer drugs. To identify small molecule inhibitors of the HIF-1 pathway, we have developed a cell-based reporter gene assay and screened a large compound library by using a quantitative high-throughput screening (qHTS approach. Results The assay is based upon a β-lactamase reporter under the control of a HRE. We have screened approximate 73,000 compounds by qHTS, with each compound tested over a range of seven to fifteen concentrations. After qHTS we have rapidly identified three novel structural series of HIF-1 pathway Inhibitors. Selected compounds in these series were also confirmed as inhibitors in a HRE β-lactamase reporter gene assay induced by low oxygen and in a VEGF secretion assay. Three of the four selected compounds tested showed significant inhibition of hypoxia-induced HIF-1α accumulation by western blot analysis. Conclusion The use of β-lactamase reporter gene assays, in combination with qHTS, enabled the rapid identification and prioritization of inhibitors specific to the hypoxia induced signaling pathway.

Additive Effects of Quorum Sensing Anti-Activators on Pseudomonas aeruginosa Virulence Traits and Transcriptome

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Kyle L. Asfahl

2018-01-01

Full Text Available In the opportunistic pathogen Pseudomonas aeruginosa, quorum sensing (QS via acyl-homoserine lactone (AHL signals coordinates virulence gene expression. AHL signals must reach a critical threshold before enough is bound by cognate regulators LasR and RhlR to drive transcription of target genes. In addition, three anti-activator proteins, QteE, QscR, and QslA, sequester QS regulators to increase the threshold for induction and delay expression of QS target genes. It remains unclear how multiple anti-activators work together to achieve the quorum threshold. Here, we employed a combination of mutational, kinetic, phenotypic, and transcriptomic analysis to examine regulatory effects and interactions of the three distinct anti-activators. We observed combinatorial, additive effects on QS gene expression. As measured by reporter gene fusion, individual deletion of each anti-activator gene increased lasB expression and QS-controlled virulence factor production. Deletion of qslA in combination with the deletion of any other anti-activator gene resulted in the greatest increase and earliest activation of lasB gene expression. Western analysis revealed that relative increases in soluble LasR in anti-activator mutants correlate with increased lasB expression and QS-controlled virulence factor production. RNA-seq of the previously uncharacterized QslA and QteE regulons revealed overlapping, yet distinct groups of differentially expressed genes. Simultaneous inactivation of qteE and qslA had the largest effect on gene expression with 999 genes induced and 798 genes repressed in the double mutant vs. wild-type. We found that LasR and RhlR-activated QS genes formed a subset of the genes induced in the qteE, qslA, and double mutant. The activation of almost all of these QS genes was advanced from stationary phase to log phase in the qteE qslA double mutant. Taken together, our results identify additive effects of anti-activation on QS gene expression, likely

Single-molecule tracking of small GTPase Rac1 uncovers spatial regulation of membrane translocation and mechanism for polarized signaling

Science.gov (United States)

Das, Sulagna; Yin, Taofei; Yang, Qingfen; Zhang, Jingqiao; Wu, Yi I.; Yu, Ji

2015-01-01

Polarized Rac1 signaling is a hallmark of many cellular functions, including cell adhesion, motility, and cell division. The two steps of Rac1 activation are its translocation to the plasma membrane and the exchange of nucleotide from GDP to GTP. It is, however, unclear whether these two processes are regulated independent of each other and what their respective roles are in polarization of Rac1 signaling. We designed a single-particle tracking (SPT) method to quantitatively analyze the kinetics of Rac1 membrane translocation in living cells. We found that the rate of Rac1 translocation was significantly elevated in protrusions during cell spreading on collagen. Furthermore, combining FRET sensor imaging with SPT measurements in the same cell, the recruitment of Rac1 was found to be polarized to an extent similar to that of the nucleotide exchange process. Statistical analysis of single-molecule trajectories and optogenetic manipulation of membrane lipids revealed that Rac1 membrane translocation precedes nucleotide exchange, and is governed primarily by interactions with phospholipids, particularly PI(3,4,5)P3, instead of protein factors. Overall, the study highlights the significance of membrane translocation in spatial Rac1 signaling, which is in addition to the traditional view focusing primarily on GEF distribution and exchange reaction. PMID:25561548

Differential Expression of Osteo-Modulatory Molecules in Periodontal Ligament Stem Cells in Response to Modified Titanium Surfaces

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So Yeon Kim

2014-01-01

Full Text Available This study assessed differential gene expression of signaling molecules involved in osteogenic differentiation of periodontal ligament stem cells (PDLSCs subjected to different titanium (Ti surface types. PDLSCs were cultured on tissue culture polystyrene (TCPS, and four types of Ti discs (PT, SLA, hydrophilic PT (pmodPT, and hydrophilic SLA (modSLA with no osteoinductive factor and then osteogenic activity, including alkaline phosphatase (ALP activity, mRNA expression of runt-related gene 2, osterix, FOSB, FRA1, and protein levels of osteopontin and collagen type IA, were examined. The highest osteogenic activity appeared in PDLSCs cultured on SLA, compared with the TCPS and other Ti surfaces. The role of surface properties in affecting signaling molecules to modulate PDLSC behavior was determined by examining the regulation of Wnt pathways. mRNA expression of the canonical Wnt signaling molecules, Wnt3a and β-catenin, was higher on SLA and modSLA than on smooth surfaces, but gene expression of the calcium-dependent Wnt signaling molecules Wnt5a, calmodulin, and NFATc1 was increased significantly on PT and pmodPT. Moreover, integrin α2/β1, sonic hedgehog, and Notch signaling molecules were affected differently by each surface modification. In conclusion, surface roughness and hydrophilicity can affect differential Wnt pathways and signaling molecules, targeting the osteogenic differentiation of PDLSCs.

A general approach to break the concentration barrier in single-molecule imaging

KAUST Repository

Loveland, Anna B.; Habuchi, Satoshi; Walter, Johannes C.; van Oijen, Antoine M.

2012-01-01

Single-molecule fluorescence imaging is often incompatible with physiological protein concentrations, as fluorescence background overwhelms an individual molecule's signal. We solve this problem with a new imaging approach called PhADE (Photo

Deep learning for single-molecule science

Science.gov (United States)

Albrecht, Tim; Slabaugh, Gregory; Alonso, Eduardo; Al-Arif, SM Masudur R.

2017-10-01

Exploring and making predictions based on single-molecule data can be challenging, not only due to the sheer size of the datasets, but also because a priori knowledge about the signal characteristics is typically limited and poor signal-to-noise ratio. For example, hypothesis-driven data exploration, informed by an expectation of the signal characteristics, can lead to interpretation bias or loss of information. Equally, even when the different data categories are known, e.g., the four bases in DNA sequencing, it is often difficult to know how to make best use of the available information content. The latest developments in machine learning (ML), so-called deep learning (DL) offer interesting, new avenues to address such challenges. In some applications, such as speech and image recognition, DL has been able to outperform conventional ML strategies and even human performance. However, to date DL has not been applied much in single-molecule science, presumably in part because relatively little is known about the ‘internal workings’ of such DL tools within single-molecule science as a field. In this Tutorial, we make an attempt to illustrate in a step-by-step guide how one of those, a convolutional neural network (CNN), may be used for base calling in DNA sequencing applications. We compare it with a SVM as a more conventional ML method, and discuss some of the strengths and weaknesses of the approach. In particular, a ‘deep’ neural network has many features of a ‘black box’, which has important implications on how we look at and interpret data.

Multivalent adhesion molecule 7 clusters act as signaling platform for host cellular GTPase activation and facilitate epithelial barrier dysfunction.

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Jenson Lim

2014-09-01

Full Text Available Vibrio parahaemolyticus is an emerging bacterial pathogen which colonizes the gastrointestinal tract and can cause severe enteritis and bacteraemia. During infection, V. parahaemolyticus primarily attaches to the small intestine, where it causes extensive tissue damage and compromises epithelial barrier integrity. We have previously described that Multivalent Adhesion Molecule (MAM 7 contributes to initial attachment of V. parahaemolyticus to epithelial cells. Here we show that the bacterial adhesin, through multivalent interactions between surface-induced adhesin clusters and phosphatidic acid lipids in the host cell membrane, induces activation of the small GTPase RhoA and actin rearrangements in host cells. In infection studies with V. parahaemolyticus we further demonstrate that adhesin-triggered activation of the ROCK/LIMK signaling axis is sufficient to redistribute tight junction proteins, leading to a loss of epithelial barrier function. Taken together, these findings show an unprecedented mechanism by which an adhesin acts as assembly platform for a host cellular signaling pathway, which ultimately facilitates breaching of the epithelial barrier by a bacterial pathogen.

Molecular locks and keys: the role of small molecules in phytohormone research

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Sandra eFonseca

2014-12-01

Full Text Available Plant adaptation, growth and development rely on the integration of many environmental and endogenous signals that collectively determine the overall plant phenotypic plasticity. Plant signalling molecules, also known as phytohormones, are fundamental to this process. These molecules act at low concentrations and regulate multiple aspects of plant fitness and development via complex signalling networks. By its nature, phytohormone research lies at the interface between chemistry and biology. Classically, the scientific community has always used synthetic phytohormones and analogs to study hormone functions and responses. However, recent advances in synthetic and combinational chemistry, have allowed a new field, plant chemical biology, to emerge and this has provided a powerful tool with which to study phytohormone function.Plant chemical biology is helping to address some of the most enduring questions in phytohormone research such as: Are there still undiscovered plant hormones? How can we identify novel signalling molecules? How can plants activate specific hormone responses in a tissue-specific manner? How can we modulate hormone responses in one developmental context without inducing detrimental effects on other processes? The chemical genomics approaches rely on the identification of small molecules modulating different biological processes and have recently identified active forms of plant hormones and molecules regulating many aspects of hormone synthesis, transport and response. We envision that the field of chemical genomics will continue to provide novel molecules able to elucidate specific aspects of hormone-mediated responses. In addition, compounds blocking specific responses could uncover how complex biological responses are regulated. As we gain information about such compounds we can design small alterations to the chemical structure to further alter specificity, enhance affinity or modulate the activity of these compounds.

Gap junction modulation by extracellular signaling molecules: the thymus model

Directory of Open Access Journals (Sweden)

Alves L.A.

2000-01-01

Full Text Available Gap junctions are intercellular channels which connect adjacent cells and allow direct exchange of molecules of low molecular weight between them. Such a communication has been described as fundamental in many systems due to its importance in coordination, proliferation and differentiation. Recently, it has been shown that gap junctional intercellular communication (GJIC can be modulated by several extracellular soluble factors such as classical hormones, neurotransmitters, interleukins, growth factors and some paracrine substances. Herein, we discuss some aspects of the general modulation of GJIC by extracellular messenger molecules and more particularly the regulation of such communication in the thymus gland. Additionally, we discuss recent data concerning the study of different neuropeptides and hormones in the modulation of GJIC in thymic epithelial cells. We also suggest that the thymus may be viewed as a model to study the modulation of gap junction communication by different extracellular messengers involved in non-classical circuits, since this organ is under bidirectional neuroimmunoendocrine control.

Paracrine signaling in a bacterium.

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López, Daniel; Vlamakis, Hera; Losick, Richard; Kolter, Roberto

2009-07-15

Cellular differentiation is triggered by extracellular signals that cause target cells to adopt a particular fate. Differentiation in bacteria typically involves autocrine signaling in which all cells in the population produce and respond to the same signal. Here we present evidence for paracrine signaling in bacterial populations-some cells produce a signal to which only certain target cells respond. Biofilm formation in Bacillus involves two centrally important signaling molecules, ComX and surfactin. ComX triggers the production of surfactin. In turn, surfactin causes a subpopulation of cells to produce an extracellular matrix. Cells that produced surfactin were themselves unable to respond to it. Likewise, once surfactin-responsive cells commenced matrix production, they no longer responded to ComX and could not become surfactin producers. Insensitivity to ComX was the consequence of the extracellular matrix as mutant cells unable to make matrix responded to both ComX and surfactin. Our results demonstrate that extracellular signaling was unidirectional, with one subpopulation producing a signal and a different subpopulation responding to it. Paracrine signaling in a bacterial population ensures the maintenance, over generations, of particular cell types even in the presence of molecules that would otherwise cause those cells to differentiate into other cell types.

Biomedical application of MALDI mass spectrometry for small-molecule analysis.

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van Kampen, Jeroen J A; Burgers, Peter C; de Groot, Ronald; Gruters, Rob A; Luider, Theo M

2011-01-01

Matrix-assisted laser desorption/ionization (MALDI) mass spectrometry (MS) is an emerging analytical tool for the analysis of molecules with molar masses below 1,000 Da; that is, small molecules. This technique offers rapid analysis, high sensitivity, low sample consumption, a relative high tolerance towards salts and buffers, and the possibility to store sample on the target plate. The successful application of the technique is, however, hampered by low molecular weight (LMW) matrix-derived interference signals and by poor reproducibility of signal intensities during quantitative analyses. In this review, we focus on the biomedical application of MALDI-MS for the analysis of small molecules and discuss its favorable properties and its challenges as well as strategies to improve the performance of the technique. Furthermore, practical aspects and applications are presented. © 2010 Wiley Periodicals, Inc.

New insights into how trafficking regulates T cell receptor signaling

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Jieqiong Lou

2016-07-01

Full Text Available AbstractThere is emerging evidence that exocytosis plays an important role in regulating T cell receptor (TCR signaling. The trafficking molecules involved in lytic granule (LG secretion in cytotoxic T lymphocytes (CTL have been well studied due to the immune disorder known as familial hemophagocytic lymphohisiocytosis (FHLH. However, the knowledge of trafficking machineries regulating the exocytosis of receptors and signaling molecules remains quite limited. In this review, we summarize the reported trafficking molecules involved in the transport of the TCR and downstream signaling molecules to the cell surface. By combining this information with the known knowledge of LG exocytosis and general exocytic trafficking machinery, we attempt to draw a more complete picture of how the TCR signaling network and exocytic trafficking matrix are interconnected to facilitate T cell activation. This also highlights how membrane compartmentalization facilitates the spatiotemporal organization of cellular responses that are essential for immune functions.

Lysosomal cysteine peptidases - Molecules signaling tumor cell death and survival.

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Pišlar, Anja; Perišić Nanut, Milica; Kos, Janko

2015-12-01

Lysosomal cysteine peptidases - cysteine cathepsins - are general intracellular protein-degrading enzymes that control also a variety of specific physiological processes. They can trigger irreversible events leading to signal transduction and activation of signaling pathways, resulting in cell survival and proliferation or cell death. In cancer cells, lysosomal cysteine peptidases are involved in multiple processes during malignant progression. Their translocation from the endosomal/lysosomal pathway to nucleus, cytoplasm, plasma membrane and extracellular space enables the activation and remodeling of a variety of tumor promoting proteins. Thus, lysosomal cysteine peptidases interfere with cytokine/chemokine signaling, regulate cell adhesion and migration and endocytosis, are involved in the antitumor immune response and apoptosis, and promote cell invasion, angiogenesis and metastasis. Further, lysosomal cysteine peptidases modify growth factors and receptors involved in tyrosine kinase dependent pathways such as MAPK, Akt and JNK, thus representing key signaling tools for the activation of tumor cell growth and proliferation. Copyright © 2015 Elsevier Ltd. All rights reserved.

Bacterial quorum sensing and nitrogen cycling in rhizosphere soil

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DeAngelis, K.M.; Lindow, S.E.; Firestone, M.K.

2008-10-01

Plant photosynthate fuels carbon-limited microbial growth and activity, resulting in increased rhizosphere nitrogen (N)-mineralization. Most soil organic N is macromolecular (chitin, protein, nucleotides); enzymatic depolymerization is likely rate-limiting for plant N accumulation. Analyzing Avena (wild oat) planted in microcosms containing sieved field soil, we observed increased rhizosphere chitinase and protease specific activities, bacterial cell densities, and dissolved organic nitrogen (DON) compared to bulk soil. Low-molecular weight DON (<3000 Da) was undetectable in bulk soil but comprised 15% of rhizosphere DON. Extracellular enzyme production in many bacteria requires quorum sensing (QS), cell-density dependent group behavior. Because proteobacteria are considered major rhizosphere colonizers, we assayed the proteobacterial QS signals acyl-homoserine lactones (AHLs), which were significantly increased in the rhizosphere. To investigate the linkage between soil signaling and N cycling, we characterized 533 bacterial isolates from Avena rhizosphere: 24% had chitinase or protease activity and AHL production; disruption of QS in 7 of 8 eight isolates disrupted enzyme activity. Many {alpha}-Proteobacteria were newly found with QS-controlled extracellular enzyme activity. Enhanced specific activities of N-cycling enzymes accompanied by bacterial density-dependent behaviors in rhizosphere soil gives rise to the hypothesis that QS could be a control point in the complex process of rhizosphere N-mineralization.

Two-colour dip spectroscopy of jet-cooled molecules

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Ito, Mitsuo

In optical-optical double resonance spectroscopy, the resonance transition from an intermediate state to a final state can be detected by a dip of the signal (fluorescence or ion) associated with the intermediate state. This method probing the signal of the intermediate state may be called `two-colour dip spectroscopy'. Various kinds of two-colour dip spectroscopy such as two-colour fluorescence/ion dip spectroscopy, two-colour ionization dip spectroscopy employing stimulated emission, population labelling spectroscopy and mass-selected ion dip spectroscopy with dissociation were briefly described, paying special attention to their characteristics in excitation, detection and application. They were extensively and successfully applied to jet-cooled large molecules and provided us with new useful information on the energy and dynamics of excited molecules.

The yeast three-hybrid system as an experimental platform to identify proteins interacting with small signaling molecules in plant cells: Potential and limitations

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Stéphanie eCottier

2011-12-01

Full Text Available Chemical genetics is a powerful scientific strategy that utilizes small bioactive molecules as experimental tools to unravel biological processes. Bioactive compounds occurring in nature represent an enormous diversity of structures that can be used to dissect functions of biological systems. Once the bioactivity of a natural or synthetic compound has been critically evaluated the challenge remains to identify its molecular target and mode of action, which usually is a time consuming and labor-intensive process. To facilitate this task, we decided to implement the yeast three-hybrid (Y3H technology as a general experimental platform to scan the whole Arabidopsis proteome for targets of small signaling molecules. The Y3H technology is based on the yeast two-hybrid system and allows direct cloning of proteins that interact in vivo with a synthetic hybrid ligand, which comprises the biologically active molecule of interest covalently linked to methotrexate (Mtx. In yeast nucleus the hybrid ligand connects two fusion proteins: the Mtx part binding to dihydrofolate reductase fused to a DNA binding domain (encoded in the yeast strain, and the bioactive molecule part binding to its potential protein target fused to a DNA activating domain (encoded on a cDNA expression vector. During cDNA library screening, the formation of this ternary, transcriptional activator complex leads to reporter gene activation in yeast cells, and thereby allows selection of the putative targets of small bioactive molecules of interest. Here we present the strategy and experimental details for construction and application of a Y3H platform, including chemical synthesis of different hybrid ligands, construction of suitable cDNA libraries, the choice of yeast strains, and appropriate screening conditions. Based on the results obtained and the current literature we discussed the perspectives and limitations of the Y3H approach for identifying targets of small bioactive molecules.

Expression patterns of signaling lymphocytic activation molecule family members in peripheral blood mononuclear cell subsets in patients with systemic lupus erythematosus.

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Karampetsou, Maria P; Comte, Denis; Kis-Toth, Katalin; Kyttaris, Vasileios C; Tsokos, George C

2017-01-01

Genome-wide linkage analysis studies (GWAS) studies in systemic lupus erythematosus (SLE) identified the 1q23 region on human chromosome 1, containing the Signaling Lymphocytic Activation Molecule Family (SLAMF) cluster of genes, as a lupus susceptibility locus. The SLAMF molecules (SLAMF1-7) are immunoregulatory receptors expressed predominantly on hematopoietic cells. Activation of cells of the adaptive immune system is aberrant in SLE and dysregulated expression of certain SLAMF molecules has been reported. We examined the expression of SLAMF1-7 on peripheral blood T cells, B cells, monocytes, and their respective differentiated subsets, in patients with SLE and healthy controls in a systematic manner. SLAMF1 levels were increased on both T cell and B cells and their differentiated subpopulations in patients with SLE. SLAMF2 was increased on SLE CD4+ and CD8+ T cells. The frequency of SLAMF4+ and SLAMF7+ central memory and effector memory CD8+ T cells was reduced in SLE patients. Naïve CD4+ and CD8+ SLE T cells showed a slight increase in SLAMF3 levels. No differences were seen in the expression of SLAMF5 and SLAMF6 among SLE patients and healthy controls. Overall, the expression of various SLAMF receptors is dysregulated in SLE and may contribute to the immunopathogenesis of the disease.

Enzyme-mediated quenching of the Pseudomonas quinolone signal (PQS promotes biofilm formation of Pseudomonas aeruginosa by increasing iron availability

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Beatrix Tettmann

2016-12-01

Full Text Available The 2-alkyl-3-hydroxy-4(1H-quinolone 2,4-dioxygenase HodC was previously described to cleave the Pseudomonas quinolone signal, PQS, which is exclusively used in the complex quorum sensing (QS system of Pseudomonas aeruginosa, an opportunistic pathogen employing QS to regulate virulence and biofilm development. Degradation of PQS by exogenous addition of HodC to planktonic cells of P. aeruginosa attenuated production of virulence factors, and reduced virulence in planta. However, proteolytic cleavage reduced the efficacy of HodC. Here, we identified the secreted protease LasB of P. aeruginosa to be responsible for HodC degradation. In static biofilms of the P. aeruginosa PA14 lasB::Tn mutant, the catalytic activity of HodC led to an increase in viable biomass in newly formed but also in established biofilms, and reduced the expression of genes involved in iron metabolism and siderophore production, such as pvdS, pvdL, pvdA and pvdQ. This is likely due to an increase in the levels of bioavailable iron by degradation of PQS, which is able to sequester iron from the surrounding environment. Thus, HodC, despite its ability to quench the production of virulence factors, is contraindicated for combating P. aeruginosa biofilms.

Approach for targeting Ras with small molecules that activate SOS-mediated nucleotide exchange.

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Burns, Michael C; Sun, Qi; Daniels, R Nathan; Camper, DeMarco; Kennedy, J Phillip; Phan, Jason; Olejniczak, Edward T; Lee, Taekyu; Waterson, Alex G; Rossanese, Olivia W; Fesik, Stephen W

2014-03-04

Aberrant activation of the small GTPase Ras by oncogenic mutation or constitutively active upstream receptor tyrosine kinases results in the deregulation of cellular signals governing growth and survival in ∼30% of all human cancers. However, the discovery of potent inhibitors of Ras has been difficult to achieve. Here, we report the identification of small molecules that bind to a unique pocket on the Ras:Son of Sevenless (SOS):Ras complex, increase the rate of SOS-catalyzed nucleotide exchange in vitro, and modulate Ras signaling pathways in cells. X-ray crystallography of Ras:SOS:Ras in complex with these molecules reveals that the compounds bind in a hydrophobic pocket in the CDC25 domain of SOS adjacent to the Switch II region of Ras. The structure-activity relationships exhibited by these compounds can be rationalized on the basis of multiple X-ray cocrystal structures. Mutational analyses confirmed the functional relevance of this binding site and showed it to be essential for compound activity. These molecules increase Ras-GTP levels and disrupt MAPK and PI3K signaling in cells at low micromolar concentrations. These small molecules represent tools to study the acute activation of Ras and highlight a pocket on SOS that may be exploited to modulate Ras signaling.

Integrated Qs Al Mudatsir in the reality group counseling to grow the character of students academic responsibility

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Asroful Kadafi

2017-11-01

The emotional development of students in early teens showed a sensitive and recreative nature (critical, emotions are often negative and temperamental. This negative passion is evidenced by the findings in the field of Indonesian teenagers, such as Tawuran, promiscuity, students who dare to do nasty with school friends (Tirto, 2013. Many factors are the cause, one of which is still the weak character of academic responsibility that students have. This problem becomes a serious problem in the world of education Indonesia. Therefore, it is natural for educational practitioners to take solutive steps to overcome the problem. One education practitioner who has a strategic position to handle the case is Counselor. Counselors are deemed able to provide practical solutions through Reality Group Counseling services by integrating spiritual values (Islam to foster student academic responsibilities. Reality group counseling emphasizes the growth of personal responsibility. This advice is also in line with Islamic values that encourage individuals always to be responsible for every action as reflected in the QS. Al Muddassir: 38.

Internal Energies of Ion-Sputtered Neutral Tryptophan and Thymine Molecules Determined by Vacuum Ultraviolet Photoionization

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Zhou, Jia; Takahashi, Lynelle; Wilson, Kevin R.; Leone, Stephen R.; Ahmed, Musahid

2010-03-11

Vacuum ultraviolet photoionization coupled to secondary neutral mass spectrometry (VUV-SNMS) of deposited tryptophan and thymine films are performed at the Chemical Dynamics Beamline. The resulting mass spectra show that while the intensity of the VUV-SNMS signal is lower than the corresponding secondary ion mass spectroscopy (SIMS) signal, the mass spectra are significantly simplified in VUV-SNMS. A detailed examination of tryptophan and thymine neutral molecules sputtered by 25 keV Bi3 + indicates that the ion-sputtered parent molecules have ~;;2.5 eV of internal energy. While this internal energy shifts the appearance energy of the photofragment ions for both tryptophan and thymine, it does not change the characteristic photoionizaton efficiency (PIE) curves of thymine versus photon energy. Further analysis of the mass spectral signals indicate that approximately 80 neutral thymine molecules and 400 tryptophan molecules are sputtered per incident Bi3 + ion. The simplified mass spectra and significant characteristic ion contributions to the VUV-SNMS spectra indicate the potential power of the technique for organic molecule surface analysis.

Glycosylation Alters Dimerization Properties of a Cell-surface Signaling Protein, Carcinoembryonic Antigen-related Cell Adhesion Molecule 1 (CEACAM1)*

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Zhuo, You; Yang, Jeong-Yeh; Moremen, Kelley W.; Prestegard, James H.

2016-01-01

Human carcinoembryonic antigen-related cell adhesion molecule 1 (C?/Au: EACAM1) is a cell-surface signaling molecule involved in cell adhesion, proliferation, and immune response. It is also implicated in cancer angiogenesis, progression, and metastasis. This diverse set of effects likely arises as a result of the numerous homophilic and heterophilic interactions that CEACAM1 can have with itself and other molecules. Its N-terminal Ig variable (IgV) domain has been suggested to be a principal player in these interactions. Previous crystal structures of the β-sandwich-like IgV domain have been produced using Escherichia coli-expressed material, which lacks native glycosylation. These have led to distinctly different proposals for dimer interfaces, one involving interactions of ABED β-strands and the other involving GFCC′C″ β-strands, with the former burying one prominent glycosylation site. These structures raise questions as to which form may exist in solution and what the effect of glycosylation may have on this form. Here, we use NMR cross-correlation measurements to examine the effect of glycosylation on CEACAM1-IgV dimerization and use residual dipolar coupling (RDC) measurements to characterize the solution structure of the non-glycosylated form. Our findings demonstrate that even addition of a single N-linked GlcNAc at potential glycosylation sites inhibits dimer formation. Surprisingly, RDC data collected on E. coli expressed material in solution indicate that a dimer using the non-glycosylated GFCC′C″ interface is preferred even in the absence of glycosylation. The results open new questions about what other factors may facilitate dimerization of CEACAM1 in vivo, and what roles glycosylation may play in heterophylic interactions. PMID:27471271

Chromosomal Rainbows detect Oncogenic Rearrangements of Signaling Molecules in Thyroid Tumors

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O' Brien, Benjamin; Jossart, Gregg H.; Ito, Yuko; Greulich-Bode, Karin M.; Weier, Jingly F.; Munne, Santiago; Clark, Orlo H.; Weier, Heinz-Ulrich G.

2010-08-19

Altered signal transduction can be considered a hallmark of many solid tumors. In thyroid cancers the receptor tyrosine kinase (rtk) genes NTRK1 (Online Mendelian Inheritance in Man = OMIM *191315, also known as 'TRKA'), RET ('Rearranged during Transfection protooncogene', OMIM *164761) and MET (OMIM *164860) have been reported as activated, rearranged or overexpressed. In many cases, a combination of cytogenetic and molecular techniques allows elucidation of cellular changes that initiate tumor development and progression. While the mechanisms leading to overexpression of the rtk MET gene remain largely unknown, a variety of chromosomal rearrangements of the RET or NTKR1 gene could be demonstrated in thyroid cancer. Abnormal expressions in these tumors seem to follow a similar pattern: the rearrangement translocates the 3'-end of the rtk gene including the entire catalytic domain to an expressed gene leading to a chimeric RNA and protein with kinase activity. Our research was prompted by an increasing number of reports describing translocations involving ret and previously unknown translocation partners. We developed a high resolution technique based on fluorescence in situ hybridization (FISH) to allow rapid screening for cytogenetic rearrangements which complements conventional chromosome banding analysis. Our technique applies simultaneous hybridization of numerous probes labeled with different reporter molecules which are distributed along the target chromosome allowing the detection of cytogenetic changes at near megabase-pair (Mbp) resolution. Here, we report our results using a probe set specific for human chromosome 10, which is altered in a significant portion of human thyroid cancers (TC's). While rendering accurate information about the cytogenetic location of rearranged elements, our multi-locus, multi-color analysis was developed primarily to overcome limitations of whole chromosome painting (WCP) and chromosome banding

Induced disease resistance signaling in plants

NARCIS (Netherlands)

Verhagen, B.W.M.; Loon, L.C. van; Pieterse, C.M.J.

2006-01-01

To protect themselves from disease, plants have evolved sophisticated inducible defense mechanisms in which the signal molecules salicylic acid, jasmonic acid and ethylene often play crucial roles. Elucidation of signaling pathways controlling induced disease resistance is a major objective in

Liposomes containing monophosphoryl lipid A and QS-21 serve as an effective adjuvant for soluble circumsporozoite protein malaria vaccine FMP013.

Science.gov (United States)

Genito, Christopher J; Beck, Zoltan; Phares, Timothy W; Kalle, Fanta; Limbach, Keith J; Stefaniak, Maureen E; Patterson, Noelle B; Bergmann-Leitner, Elke S; Waters, Norman C; Matyas, Gary R; Alving, Carl R; Dutta, Sheetij

2017-07-05

Malaria caused by Plasmodium falciparum continues to threaten millions of people living in the tropical parts of the world. A vaccine that confers sterile and life-long protection remains elusive despite more than 30years of effort and resources invested in solving this problem. Antibodies to a malaria vaccine candidate circumsporozoite protein (CSP) can block invasion and can protect humans against malaria. We have manufactured the Falciparum Malaria Protein-013 (FMP013) vaccine based on the nearly full-length P. falciparum CSP 3D7 strain sequence. We report here immunogenicity and challenge data on FMP013 antigen in C57BL/6 mice formulated with two novel adjuvants of the Army Liposome Formulation (ALF) series and a commercially available adjuvant Montanide ISA 720 (Montanide) as a control. ALF is a liposomal adjuvant containing a synthetic monophosphoryl lipid A (3D-PHAD®). In our study, FMP013 was adjuvanted with ALF alone, ALF containing aluminum hydroxide (ALFA) or ALF containing QS-21 (ALFQ). Adjuvants ALF and ALFA induced similar antibody titers and protection against transgenic parasite challenge that were comparable to Montanide. ALFQ was superior to the other three adjuvants as it induced higher antibody titers with improved boosting after the third immunization, higher serum IgG2c titers, and enhanced protection. FMP013+ALFQ also augmented the numbers of splenic germinal center-derived activated B-cells and antibody secreting cells compared to Montanide. Further, FMP013+ALFQ induced antigen-specific IFN-γ ELISPOT activity, CD4 + T-cells and a T H 1-biased cytokine profile. These results demonstrate that soluble CSP can induce a potent and sterile protective immune response when formulated with the QS-21 containing adjuvant ALFQ. Comparative mouse immunogenicity data presented here were used as the progression criteria for an ongoing non-human primate study and a regulatory toxicology study in preparation for a controlled human malaria infection (CHMI

Recent advances in the discovery of small molecule c-Met Kinase inhibitors.

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Parikh, Palak K; Ghate, Manjunath D

2018-01-01

c-Met is a prototype member of a subfamily of heterodimeric receptor tyrosine kinases (RTKs) and is the receptor for hepatocyte growth factor (HGF). Binding of HGF to its receptor c-Met, initiates a wide range of cellular signalling, including those involved in proliferation, motility, migration and invasion. Importantly, dysregulated HGF/c-Met signalling is a driving factor for numerous malignancies and promotes tumour growth, invasion, dissemination and/or angiogenesis. Dysregulated HGF/c-Met signalling has also been associated with poor clinical outcomes and resistance acquisition to some approved targeted therapies. Thus, c-Met kinase has emerged as a promising target for cancer drug development. Different therapeutic approaches targeting the HGF/c-Met signalling pathway are under development for targeted cancer therapy, among which small molecule inhibitors of c-Met kinase constitute the largest effort within the pharmaceutical industry. The review is an effort to summarize recent advancements in medicinal chemistry development of small molecule c-Met kinase inhibitors as potential anti-cancer agents which would certainly help future researchers to bring further developments in the discovery of small molecule c-Met kinase inhibitors. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

The quality of health care and patient satisfaction: an exploratory investigation of the 5Qs model at some Egyptian and Jordanian medical clinics.

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Zineldin, Mosad

2006-01-01

To examine the major factors affecting patients' perception of cumulative satisfaction and to address the question whether patients in Egypt and Jordan evaluate quality of health care similarly or differently. A conceptual model including behavioural dimensions of patient-physician relationships and patient satisfaction has been developed. As the empirical research setting, this study concerns three hospitals in Egypt and Jordan. The survey instrument in a questionnaire form was designed to achieve the research objectives. A total of 48 items (attributes) of the newly developed five quality dimensions were identified to be the most relevant. A total of 224 complete and usable questionnaires were received from the in-patients. Hospital C has above-average total and dimensional qualities and patients are the most satisfied in accordance with all dimensions of services. Hospitals A and B have under-average total qualities as the majority of patients are not satisfied with services. Comparing hospitals A and B, in the majority of dimensions (with the exception of Q5), the quality in hospital B is higher than in hospital A. Patients' satisfaction with different service quality dimensions is correlated with their willingness to recommend the hospital to others. A cure to improve the quality for health-care services can be an application of total relationship management and the 5Qs model together with customer orientation strategy. The result can be used by the hospitals to reengineer and redesign creatively their quality management processes and the future direction of their more effective health-care quality strategies. In this research a study is described involving a new instrument and a new method which assure a reasonable level of relevance, validity and reliability, while being explicitly change-oriented. This study argues that a patient's satisfaction is a cumulative construct, summing satisfaction with five different qualities (5Qs) of the hospital: quality of

Dissecting Repulsive Guidance Molecule/Neogenin function and signaling during neural development

NARCIS (Netherlands)

van den Heuvel, D.M.A.

2013-01-01

During neural development a series of precisely ordered cellular processes acts to establish a functional brain comprising millions of neurons and many more neuronal connections. Neogenin and its repulsive guidance molecule (RGM) ligands contribute to neuronal network formation by inducing axon

A sensitive fluorescence reporter for monitoring quorum sensing regulated protease production in Vibrio harveyi.

Science.gov (United States)

Rajamani, Sathish; Sayre, Richard T

2011-02-01

Many bacteria produce and secrete proteases during host invasion and pathogenesis. Vibrio harveyi, an opportunistic pathogen of shrimp, is known to use a two-component quorum sensing (QS) mechanism for coordination of gene expression including protease secretion at high population densities. We examined the role of V. harveyi's QS signaling molecules, N-(3-hydroxybutanoyl)-L-homoserine lactone (AI-1) and the boron derivative of autoinducer-2 (BAI-2) in extracellular protease production. A fusion protein, M3CLPY (Rajamani et al., 2007), consisting of a large protease sensitive BAI-2 mutant receptor LuxP (~38kDa) flanked by two protease insensitive cyan and yellow variants of GFP (~28kDa each) was utilized as a substrate to detect secreted protease activity. The M3CLPY fusion, with the addition of wild-type V. harveyi (BB120) cell-free culture filtrate showed a time-dependent loss in fluorescence resonance energy transfer (FRET) associated with the cleavage of the LuxP linker protein and hence separation of the two fluorophores. This cleavage of LuxP linker protein leading to decreased FRET efficiency was further confirmed by immunoblotting using anti-GFP antibody. The addition of cell-free filtrates from strains defective in one or both of the two-component QS pathways: luxN(-) (defective in AI-1), luxS(-) (defective in BAI-2), and luxN(-)/luxS(-) (defective in both AI-1/BAI-2) showed differential levels of protease production. The observed protease activities were most pronounced in wild-type, followed by the AI-1 defective mutant (BB170) and the least for luxS(-) mutant (MM30) and luxN(-)/luxS(-) double mutant (MM32) strains. Incidentally, the lowest protease producing strains MM30 and MM32 were both defective in BAI-2 production. This observation was validated by addition of synthetic BAI-2 to MM30 and MM32 strains to restore protease production. Our results indicate that BAI-2 signaling in the two-component QS pathway plays the key role in regulating

Signal Transduction Pathways of TNAP: Molecular Network Analyses.

Science.gov (United States)

Négyessy, László; Györffy, Balázs; Hanics, János; Bányai, Mihály; Fonta, Caroline; Bazsó, Fülöp

2015-01-01

Despite the growing body of evidence pointing on the involvement of tissue non-specific alkaline phosphatase (TNAP) in brain function and diseases like epilepsy and Alzheimer's disease, our understanding about the role of TNAP in the regulation of neurotransmission is severely limited. The aim of our study was to integrate the fragmented knowledge into a comprehensive view regarding neuronal functions of TNAP using objective tools. As a model we used the signal transduction molecular network of a pyramidal neuron after complementing with TNAP related data and performed the analysis using graph theoretic tools. The analyses show that TNAP is in the crossroad of numerous pathways and therefore is one of the key players of the neuronal signal transduction network. Through many of its connections, most notably with molecules of the purinergic system, TNAP serves as a controller by funnelling signal flow towards a subset of molecules. TNAP also appears as the source of signal to be spread via interactions with molecules involved among others in neurodegeneration. Cluster analyses identified TNAP as part of the second messenger signalling cascade. However, TNAP also forms connections with other functional groups involved in neuronal signal transduction. The results indicate the distinct ways of involvement of TNAP in multiple neuronal functions and diseases.

Regulation of ITAM adaptor molecules and their receptors by inhibition of calcineurin-NFAT signalling during late stage osteoclast differentiation

Energy Technology Data Exchange (ETDEWEB)

Zawawi, M.S.F. [Universiti Sains Malaysia (USM) (Malaysia); Discipline of Anatomy and Pathology, School of Medical Sciences, University of Adelaide, Adelaide, SA 5005 (Australia); Dharmapatni, A.A.S.S.K.; Cantley, M.D. [Discipline of Anatomy and Pathology, School of Medical Sciences, University of Adelaide, Adelaide, SA 5005 (Australia); McHugh, K.P. [University of Florida, College of Dentistry, Fl (United States); Haynes, D.R. [Discipline of Anatomy and Pathology, School of Medical Sciences, University of Adelaide, Adelaide, SA 5005 (Australia); Crotti, T.N., E-mail: tania.crotti@adelaide.edu.au [Discipline of Anatomy and Pathology, School of Medical Sciences, University of Adelaide, Adelaide, SA 5005 (Australia)

2012-10-19

Highlights: Black-Right-Pointing-Pointer Calcineurin/NFAT inhibitors FK506 and VIVIT treated human PBMC derived osteoclasts in vitro. Black-Right-Pointing-Pointer Differential regulation of ITAM receptors and adaptor molecules by calcineurin/NFAT inhibitors. Black-Right-Pointing-Pointer FK506 and VIVIT suppress ITAM factors during late phase osteoclast differentiation. -- Abstract: Osteoclasts are specialised bone resorptive cells responsible for both physiological and pathological bone loss. Osteoclast differentiation and activity is dependent upon receptor activator NF-kappa-B ligand (RANKL) interacting with its receptor RANK to induce the transcription factor, nuclear factor of activated T-cells, cytoplasmic, calcineurin-dependent 1 (NFATc1). The immunoreceptor tyrosine-based activation motif (ITAM)-dependent pathway has been identified as a co-stimulatory pathway in osteoclasts. Osteoclast-associated receptor (OSCAR) and triggering receptor expressed in myeloid cells (TREM2) are essential receptors that pair with adaptor molecules Fc receptor common gamma chain (FcR{gamma}) and DNAX-activating protein 12 kDa (DAP12) respectively to induce calcium signalling. Treatment with calcineurin-NFAT inhibitors, Tacrolimus (FK506) and the 11R-VIVIT (VIVIT) peptide, reduces NFATc1 expression consistent with a reduction in osteoclast differentiation and activity. This study aimed to investigate the effects of inhibiting calcineurin-NFAT signalling on the expression of ITAM factors and late stage osteoclast genes including cathepsin K (CathK), Beta 3 integrin ({beta}3) and Annexin VIII (AnnVIII). Human peripheral blood mononuclear cells (PBMCs) were differentiated with RANKL and macrophage-colony stimulating factor (M-CSF) over 10 days in the presence or absence of FK506 or VIVIT. Osteoclast formation (as assessed by tartrate resistant acid phosphatase (TRAP)) and activity (assessed by dentine pit resorption) were significantly reduced with treatment. Quantitative real

Single Molecules as Optical Probes for Structure and Dynamics

Science.gov (United States)

Orrit, Michel

Single molecules and single nanoparticles are convenient links between the nanoscale world and the laboratory. We discuss the limits for their optical detection by three different methods: fluorescence, direct absorption, and photothermal detection. We briefly review some recent illustrations of qualitatively new information gathered from single-molecule signals: intermittency of the fluorescence intensity, acoustic vibrations of nanoparticles (1-100 GHz) or of extended defects in molecular crystals (0.1-1 MHz), and dynamical heterogeneity in glass-forming molecular liquids. We conclude with an outlook of future uses of single-molecule methods in physical chemistry, soft matter, and material science.

A generalizable platform for interrogating target- and signal-specific consequences of electrophilic modifications in redox-dependent cell signaling.

Science.gov (United States)

Lin, Hong-Yu; Haegele, Joseph A; Disare, Michael T; Lin, Qishan; Aye, Yimon

2015-05-20

Despite the known propensity of small-molecule electrophiles to react with numerous cysteine-active proteins, biological actions of individual signal inducers have emerged to be chemotype-specific. To pinpoint and quantify the impacts of modifying one target out of the whole proteome, we develop a target-protein-personalized "electrophile toolbox" with which specific intracellular targets can be selectively modified at a precise time by specific reactive signals. This general methodology, T-REX (targetable reactive electrophiles and oxidants), is established by (1) constructing a platform that can deliver a range of electronic and sterically different bioactive lipid-derived signaling electrophiles to specific proteins in cells; (2) probing the kinetics of targeted delivery concept, which revealed that targeting efficiency in cells is largely driven by initial on-rate of alkylation; and (3) evaluating the consequences of protein-target- and small-molecule-signal-specific modifications on the strength of downstream signaling. These data show that T-REX allows quantitative interrogations into the extent to which the Nrf2 transcription factor-dependent antioxidant response element (ARE) signaling is activated by selective electrophilic modifications on Keap1 protein, one of several redox-sensitive regulators of the Nrf2-ARE axis. The results document Keap1 as a promiscuous electrophile-responsive sensor able to respond with similar efficiencies to discrete electrophilic signals, promoting comparable strength of Nrf2-ARE induction. T-REX is also able to elicit cell activation in cases in which whole-cell electrophile flooding fails to stimulate ARE induction prior to causing cytotoxicity. The platform presents a previously unavailable opportunity to elucidate the functional consequences of small-molecule-signal- and protein-target-specific electrophilic modifications in an otherwise unaffected cellular background.

[The Effect of Introduction of the Heterologous Gene Encoding the N-acyl-homoserine Lactonase (aiiA) on the Properties of Burkholderia cenocepacia 370].

Science.gov (United States)

Plyuta, V A; Lipasova, V A; Koksharova, O A; Veselova, M A; Kuznetsov, A E; Khmel, I A

2015-08-01

To study the role of Quorum Sensing (QS) regulation in the control of the cellular processes of Burkholderia cenocepacia 370, plasmid pME6863 was transferred into its cells. The plasmid contains a heterologous gene encoding for AiiA N-acyl-homoserine lactonase, which degrades the signaling molecules of the QS system of N-acyl-homoserine lactones (AHL). An absence or reduction of AHL in the culture was revealed with the biosensors Chromobacterium violaceum CV026 and Agrobacterium tumifaciens NT1/pZLR4, respectively. The presence of the aiiA gene, which was cloned from Bacillus sp. A24 in the cells of B. cenocepacia 370, resulted in a lack of hemolytic activity, which reduced the extracellular proteolytic activity and decreased the cells' ability to migration in swarms on the surface of the agar medium. The introduction of the aiiA gene did not affect lipase activity, fatty acids synthesis, HCN synthesis, or biofilm formation. Hydrogen peroxide was shown to stimulate biofilm formation by B. cenocepacia 370 in concentrations that inhibited or weakly suppressed bacterial growth. The introduction of the aiiA gene into the cells did not eliminate this effect but it did reduce it.

Quorum sensing signals are produced by Aeromonas salmonicida and quorum sensing inhibitors can reduce production of a potential virulence factor

DEFF Research Database (Denmark)

Rasch, Maria; Kastbjerg, Vicky Gaedt; Bruhn, Jesper Bartholin

2007-01-01

Many pathogens control production of virulence factors by self-produced signals in a process called quorum sensing (QS). We demonstrate that acyl homoserine lactone (AHL) signals, which enable bacteria to express certain phenotypes in relation to cell density, are produced by a wide spectrum...... of Aeromonas salmonicida strains. All 31 typical strains were AHL producers as were 21 of 26 atypical strains, but on a strain population basis, production of virulence factors such as protease, lipase, A-layer or pigment did not correlate with the production and accumulation of AHLs in the growth medium...... of Aeromonas salmonicida. The most efficient compound N-(heptylsulfanylacetyl)-L-homoserine lactone (HepS-AHL), reduced protease production by a factor of 10. Five extracellular proteases were detected on gelatin-containing sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) gels and 3...

Force microscopy on insulators: imaging of organic molecules

International Nuclear Information System (INIS)

Pfeiffer, O; Gnecco, E; Zimmerli, L; Maier, S; Meyer, E; Nony, L; Bennewitz, R; Diederich, F; Fang, H; Bonifazi, D

2005-01-01

So far, most of the high resolution scanning probe microscopy studies of organic molecules were restricted to metallic substrates. Insulating substrates are mandatory when the molecules need to be electrically decoupled in a electronic circuit. In such a case, atomic force microscopy is required. In this paper we will discuss our recent studies on different organic molecules deposited on KBr surfaces in ultra-high vacuum, and then imaged by AFM at room temperature. The distance between tip and surface was controlled either by the frequency-shift of the cantilever resonance or by the excitation signal required to keep the oscillation amplitude constant. Advantages and drawbacks of both techniques are discussed. The high mobility of the molecules, due to their weak interaction with the substrate, hinders the formation of regular self assembled structures. To overcome this problem we created artificial structures on the surface by annealing and by electron irradiation, which made possible the growth of the molecules onto step edges and their confinement into rectangular pits

Analysis of global gene expression profile of rice in response to methylglyoxal indicates its possible role as a stress signal molecule

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Charanpreet eKaur

2015-09-01

Full Text Available Methylglyoxal (MG is a toxic metabolite produced primarily as a byproduct of glycolysis. Being a potent glycating agent, it can readily bind macromolecules like DNA, RNA or proteins, modulating their expression and activity. In plants, despite the known inhibitory effects of MG on growth and development, still limited information is available about the molecular mechanisms and response pathways elicited upon elevation in MG levels. To gain insight into the molecular basis of MG response, we have investigated changes in global gene expression profiles in rice upon exposure to exogenous MG using GeneChip microarrays. Initially, growth of rice seedlings was monitored in response to increasing MG concentrations which could retard plant growth in a dose-dependent manner. Upon exposure to 10 mM concentration of MG, a total of 1685 probe sets were up- or down-regulated by more than 1.5-fold in shoot tissues within 16 h. These were classified into ten functional categories. The genes involved in signal transduction such as, protein kinases and transcription factors, were significantly over-represented in the perturbed transcriptome, of which several are known to be involved in abiotic and biotic stress response indicating a cross-talk between MG-responsive and stress-responsive signal transduction pathways. Through in silico studies, we could predict 7-8 bp long conserved motif as a possible MG-responsive element (MGRE in the 1 kb upstream region of genes that were more than ten-fold up- or down-regulated in the analysis. Since several perturbations were found in signaling cascades in response to MG, we hereby suggest that it plays an important role in signal transduction probably acting as a stress signal molecule.

Differential effects of exposure to maternal obesity or maternal weight loss during the periconceptional period in the sheep on insulin signalling molecules in skeletal muscle of the offspring at 4 months of age.

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Lisa M Nicholas

Full Text Available Exposure to maternal obesity before and/or throughout pregnancy may increase the risk of obesity and insulin resistance in the offspring in childhood and adult life, therefore, resulting in its transmission into subsequent generations. We have previously shown that exposure to maternal obesity around the time of conception alone resulted in increased adiposity in female lambs. Changes in the abundance of insulin signalling molecules in skeletal muscle and adipose tissue precede the development of insulin resistance and type 2 diabetes. It is not clear, however, whether exposure to maternal obesity results in insulin resistance in her offspring as a consequence of the impact of increased adiposity on skeletal muscle or as a consequence of the programming of specific changes in the abundance of insulin signalling molecules in this tissue. We have used an embryo transfer model in the sheep to investigate the effects of exposure to either maternal obesity or to weight loss in normal and obese mothers preceding and for one week after conception on the expression and abundance of insulin signalling molecules in muscle in the offspring. We found that exposure to maternal obesity resulted in lower muscle GLUT-4 and Ser 9 phospho-GSK3α and higher muscle GSK3α abundance in lambs when compared to lambs conceived in normally nourished ewes. Exposure to maternal weight loss in normal or obese mothers, however, resulted in lower muscle IRS1, PI3K, p110β, aPKCζ, Thr 642 phospho-AS160 and GLUT-4 abundance in the offspring. In conclusion, maternal obesity or weight loss around conception have each programmed specific changes on subsets of molecules in the insulin signalling, glucose transport and glycogen synthesis pathways in offspring. There is a need for a stronger evidence base to ensure that weight loss regimes in obese women seeking to become pregnant minimize the metabolic costs for the next generation.

Small-molecule synthetic compound norcantharidin reverses multi-drug resistance by regulating Sonic hedgehog signaling in human breast cancer cells.

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Yu-Jen Chen

Full Text Available Multi-drug resistance (MDR, an unfavorable factor compromising treatment efficacy of anticancer drugs, involves upregulated ATP binding cassette (ABC transporters and activated Sonic hedgehog (Shh signaling. By preparing human breast cancer MCF-7 cells resistant to doxorubicin (DOX, we examined the effect and mechanism of norcantharidin (NCTD, a small-molecule synthetic compound, on reversing multidrug resistance. The DOX-prepared MCF-7R cells also possessed resistance to vinorelbine, characteristic of MDR. At suboptimal concentration, NCTD significantly inhibited the viability of DOX-sensitive (MCF-7S and DOX-resistant (MCF-7R cells and reversed the resistance to DOX and vinorelbine. NCTD increased the intracellular accumulation of DOX in MCF-7R cells and suppressed the upregulated the mdr-1 mRNA, P-gp and BCRP protein expression, but not the MRP-1. The role of P-gp was strengthened by partial reversal of the DOX and vinorelbine resistance by cyclosporine A. NCTD treatment suppressed the upregulation of Shh expression and nuclear translocation of Gli-1, a hallmark of Shh signaling activation in the resistant clone. Furthermore, the Shh ligand upregulated the expression of P-gp and attenuated the growth inhibitory effect of NCTD. The knockdown of mdr-1 mRNA had not altered the expression of Shh and Smoothened in both MCF-7S and MCF-7R cells. This indicates that the role of Shh signaling in MDR might be upstream to mdr-1/P-gp, and similar effect was shown in breast cancer MDA-MB-231 and BT-474 cells. This study demonstrated that NCTD may overcome multidrug resistance through inhibiting Shh signaling and expression of its downstream mdr-1/P-gp expression in human breast cancer cells.

Information Thermodynamics of the Cell Signal Transduction as a Szilard Engine

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Tatsuaki Tsuruyama

2018-03-01

Full Text Available A cell signaling system is in a non-equilibrium state, and it includes multistep biochemical signaling cascades (BSCs, which involve phosphorylation of signaling molecules, such as mitogen-activated protein kinase (MAPK pathways. In this study, the author considered signal transduction description using information thermodynamic theory. The ideal BSCs can be considered one type of the Szilard engine, and the presumed feedback controller, Maxwell’s demon, can extract the work during signal transduction. In this model, the mutual entropy and chemical potential of the signal molecules can be redefined by the extracted chemical work in a mechanicochemical model, Szilard engine, of BSC. In conclusion, signal transduction is computable using the information thermodynamic method.

Using a Spectrofluorometer for Resonance Raman Spectra of Organic Molecules

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Vadivel Masilamani

2017-01-01

Full Text Available Scattering (Rayleigh and Raman and fluorescence are two common light signals that frequently occur together, confusing the researchers and graduate students experimenting in molecular spectroscopy laboratories. This report is a brief study presenting a clear discrimination between the two signals mentioned, employing a common spectrofluorometer such as the PerkinElmer LS 55. Even better, the resonance Raman signal of a molecule (e.g., acetone can be obtained elegantly using the same instrument.

The Effects of Chinese Herbal Medicines on the Quorum Sensing-Regulated Virulence in Pseudomonas aeruginosa PAO1

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Yee Meng Chong

2018-04-01

Full Text Available The quorum sensing (QS system has been used by many opportunistic pathogenic bacteria to coordinate their virulence determinants in relation to cell-population density. As antibiotic-resistant bacteria are on the rise, interference with QS has been regarded as a novel way to control bacterial infections. As such, many plant-based natural products have been widely explored for their therapeutic roles. These natural products may contain anti-QS compounds that could block QS signals generation or transmission to combat QS pathogens. In this study, we report the anti-QS activities of four different Chinese herbal plant extracts: Poria cum Radix pini, Angelica dahurica, Rhizoma cibotii and Schizonepeta tenuifolia, on Pseudomonas aeruginosa PAO1. All the plants extracted using hexane, chloroform and methanol were tested and found to impair swarming motility and pyocyanin production in P. aeruginosa PAO1, particularly by Poria cum Radix pini. In addition, all the plant extracts also inhibited violacein production in C. violaceum CV026 up to 50% while bioluminescence activities were reduced in lux-based E. coli biosensors, pSB401 and pSB1075, up to about 57%. These anti-QS properties of the four medicinal plants are the first documentation that demonstrates a potential approach to attenuate pathogens’ virulence determinants.

Signaling Role of Fructose Mediated by FINS1/FBP in Arabidopsis thaliana

Science.gov (United States)

Cho, Young-Hee; Yoo, Sang-Dong

2011-01-01

Sugars are evolutionarily conserved signaling molecules that regulate the growth and development of both unicellular and multicellular organisms. As sugar-producing photosynthetic organisms, plants utilize glucose as one of their major signaling molecules. However, the details of other sugar signaling molecules and their regulatory factors have remained elusive, due to the complexity of the metabolite and hormone interactions that control physiological and developmental programs in plants. We combined information from a gain-of-function cell-based screen and a loss-of-function reverse-genetic analysis to demonstrate that fructose acts as a signaling molecule in Arabidopsis thaliana. Fructose signaling induced seedling developmental arrest and interacted with plant stress hormone signaling in a manner similar to that of glucose. For fructose signaling responses, the plant glucose sensor HEXOKINASE1 (HXK1) was dispensable, while FRUCTOSE INSENSITIVE1 (FINS1), a putative FRUCTOSE-1,6-BISPHOSPHATASE, played a crucial role. Interestingly, FINS1 function in fructose signaling appeared to be independent of its catalytic activity in sugar metabolism. Genetic analysis further indicated that FINS1–dependent fructose signaling may act downstream of the abscisic acid pathway, in spite of the fact that HXK1–dependent glucose signaling works upstream of hormone synthesis. Our findings revealed that multiple layers of controls by fructose, glucose, and abscisic acid finely tune the plant autotrophic transition and modulate early seedling establishment after seed germination. PMID:21253566

Fast recognition of single molecules based on single-event photon statistics

International Nuclear Information System (INIS)

Dong Shuangli; Huang Tao; Liu Yuan; Wang Jun; Zhang Guofeng; Xiao Liantuan; Jia Suotang

2007-01-01

Mandel's Q parameter, which is determined from single-event photon statistics, provides an alternative way to recognize single molecules with fluorescence detection, other than the second-order correlation function. It is shown that the Q parameter of an assumed ideal double-molecule fluorescence with the same average photon number as that of the sample fluorescence can act as the criterion for single-molecule recognition. The influence of signal-to-background ratio and the error estimates for photon statistics are also presented. We have applied this method to ascertain single Cy5 dye molecules within hundreds of milliseconds

The role of purinergic signalling in exocrine pancreas

DEFF Research Database (Denmark)

Haanes, Kristian Agmund

ATP is a fundamentally important molecule in intracellular processes, especially recognised as the molecular source of energy. ATP is however also released as a signal from most cell types, and extracellular signalling by ATP goes under the common name purinergic signalling and it includes releas...

AHL signaling molecules with a large acyl chain enhance biofilm formation on sulfur and metal sulfides by the bioleaching bacterium Acidithiobacillus ferrooxidans.

Science.gov (United States)

González, Alex; Bellenberg, Sören; Mamani, Sigde; Ruiz, Lina; Echeverría, Alex; Soulère, Laurent; Doutheau, Alain; Demergasso, Cecilia; Sand, Wolfgang; Queneau, Yves; Vera, Mario; Guiliani, Nicolas

2013-04-01

Biofilm formation plays a pivotal role in bioleaching activities of bacteria in both industrial and natural environments. Here, by visualizing attached bacterial cells on energetic substrates with different microscopy techniques, we obtained the first direct evidence that it is possible to positively modulate biofilm formation of the extremophilic bacterium Acidithiobacillus ferrooxidans on sulfur and pyrite surfaces by using Quorum Sensing molecules of the N-acylhomoserine lactone type (AHLs). Our results revealed that AHL-signaling molecules with a long acyl chain (12 or 14 carbons) increased the adhesion of A. ferrooxidans cells to these substrates. In addition, Card-Fish experiments demonstrated that C14-AHL improved the adhesion of indigenous A. ferrooxidans cells from a mixed bioleaching community to pyrite. Finally, we demonstrated that this improvement of cell adhesion is correlated with an increased production of extracellular polymeric substances. Our results open up a promising means to develop new strategies for the improvement of bioleaching efficiency and metal recovery, which could also be used to control environmental damage caused by acid mine/rock drainage.

Serine/threonine phosphatase tapp2cs might be served as an early signal molecule for water stress in wheat

International Nuclear Information System (INIS)

Song, K. H.; Tian, W. L.; Hou, B. Z.; Guo, J. X.; Mei, X. R.; Li, Y. Z.

2015-01-01

Much progress has been made towards understanding the role of serine/threonine phosphatases type 2C (PP2Cs) in abscisic acid (ABA) signaling transduction. However, how the negative regulator, PP2Cs, responds to plant water loss remains unclear. Here, we used a series of relative soil moisture (RSM: 85 percentage (well watered), 65 percentage (moderate stress), 45 percentage (severe stress) potted winter wheat (Triticum aestivum L.) and the detached leaves to detect ABA levels and transcripts of PP2Cs, including PP2C40, PP2C45, PP2C59 and PP2C6 as well as the core downstream signals of ABA, including ABF, SnRK2.4 and SnRK2.5. The results showed that the continual loss of water led to a consistent increase in ABA levels, and that the mRNA expression levels of PP2Cs were dependent on plant water condition. PP2Cs expression could be induced by a slight loss of water, and inhibited under severe loss of water. These results were further confirmed by the transcripts of ABF, SnRK2.4 and SnRK2.5. Furthermore, in slight loss of water, 100 μM exogenous ABA could promote PP2Cs expression; in severe loss of water, it inhibited PP2Cs expression. In conclusion, ABA accumulation is controlled by water condition and the PP2C expression is dependent on plant water condition, suggesting that PP2Cs might be served as an early signal molecule for water stress in wheat. (author)

Chemical Modulation of WNT Signaling in Cancer.

Science.gov (United States)

Zhang, Li-Shu; Lum, Lawrence

2018-01-01

Genetically based observations stemming from defects in development and in regeneration form the foundation of our understanding regarding how the secreted WNT proteins control coordinated cell fate decision-making in adult tissues. At the same time, our anticipation of potential benefits and unwanted toxicities associated with candidate anticancer agents targeting WNT signal transduction are also reliant upon this blueprint of WNT-associated physiology. Despite the long established role of WNT signaling in cancer, the emergence of WNT signaling as a suppressor of immunological attack in melanoma reveals an unanticipated anticancer potential in targeting WNT signaling. Here we review the literature associated with WNT signaling in cancer and discuss potential challenges that may be associated with the chemical attack of this important cellular process in achieving therapeutic goals. Although a number of small molecules targeting WNT signaling are introduced here, we center our discussion on antagonists of the WNT acyltransferase porcupine (PORCN) given the recent entry of two candidate molecules in clinical testing. Copyright © 2018 Elsevier Inc. All rights reserved.

Clinical development of galunisertib (LY2157299 monohydrate, a small molecule inhibitor of transforming growth factor-beta signaling pathway

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Herbertz S

2015-08-01

Full Text Available Stephan Herbertz,1 J Scott Sawyer,2 Anja J Stauber,2 Ivelina Gueorguieva,3 Kyla E Driscoll,4 Shawn T Estrem,2 Ann L Cleverly,3 Durisala Desaiah,2 Susan C Guba,2 Karim A Benhadji,2 Christopher A Slapak,2 Michael M Lahn21Lilly Deutschland GmbH, Bad Homburg, Germany; 2Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, IN, USA; 3Lilly Research Laboratories, Eli Lilly and Company, Windlesham, Surrey, UK; 4Lilly Research Laboratories, Eli Lilly and Company, New York, NY, USA Abstract: Transforming growth factor-beta (TGF-β signaling regulates a wide range of biological processes. TGF-β plays an important role in tumorigenesis and contributes to the hallmarks of cancer, including tumor proliferation, invasion and metastasis, inflammation, angiogenesis, and escape of immune surveillance. There are several pharmacological approaches to block TGF-β signaling, such as monoclonal antibodies, vaccines, antisense oligonucleotides, and small molecule inhibitors. Galunisertib (LY2157299 monohydrate is an oral small molecule inhibitor of the TGF-β receptor I kinase that specifically downregulates the phosphorylation of SMAD2, abrogating activation of the canonical pathway. Furthermore, galunisertib has antitumor activity in tumor-bearing animal models such as breast, colon, lung cancers, and hepatocellular carcinoma. Continuous long-term exposure to galunisertib caused cardiac toxicities in animals requiring adoption of a pharmacokinetic/pharmacodynamic-based dosing strategy to allow further development. The use of such a pharmacokinetic/pharmacodynamic model defined a therapeutic window with an appropriate safety profile that enabled the clinical investigation of galunisertib. These efforts resulted in an intermittent dosing regimen (14 days on/14 days off, on a 28-day cycle of galunisertib for all ongoing trials. Galunisertib is being investigated either as monotherapy or in combination with standard antitumor regimens (including nivolumab

Unusual Multiple Production of N-Acylhomoserine Lactones a by Burkholderia sp. Strain C10B Isolated from Dentine Caries

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Share Yuan Goh

2014-05-01

Full Text Available Bacteria realize the ability to communicate by production of quorum sensing (QS molecules called autoinducers, which regulate the physiological activities in their ecological niches. The oral cavity could be a potential area for the presence of QS bacteria. In this study, we report the isolation of a QS bacterial isolate C10B from dentine caries. Preliminary screening using Chromobacterium violaceum CV026 biosensor showed that isolate C10B was able to produce N-acylhomoserine lactones (AHLs. This bacterium was further identified as a member of Burkholderia, an opportunistic pathogen. The isolated Burkholderia sp. was confirmed to produce N-hexanoyl-L-homoserine lactone (C6-HSL, N-octanoyl-L-homoserine lactone (C8-HSL, N-decanoyl-L-homoserine lactone (C10-HSL and N-dodecanoyl-L-homoserine lactone (C12-HSL.

Expression analysis of taste signal transduction molecules in the fungiform and circumvallate papillae of the rhesus macaque, Macaca mulatta.

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Yoshiro Ishimaru

Full Text Available The molecular mechanisms of the mammalian gustatory system have been examined in many studies using rodents as model organisms. In this study, we examined the mRNA expression of molecules involved in taste signal transduction in the fungiform papillae (FuP and circumvallate papillae (CvP of the rhesus macaque, Macaca mulatta, using in situ hybridization. TAS1R1, TAS1R2, TAS2Rs, and PKD1L3 were exclusively expressed in different subsets of taste receptor cells (TRCs in the FuP and CvP. This finding suggests that TRCs sensing different basic taste modalities are mutually segregated in macaque taste buds. Individual TAS2Rs exhibited a variety of expression patterns in terms of the apparent level of expression and the number of TRCs expressing these genes, as in the case of human TAS2Rs. GNAT3, but not GNA14, was expressed in TRCs of FuP, whereas GNA14 was expressed in a small population of TRCs of CvP, which were distinct from GNAT3- or TAS1R2-positive TRCs. These results demonstrate similarities and differences between primates and rodents in the expression profiles of genes involved in taste signal transduction.

Anti-Quorum Sensing Potential of Potato Rhizospheric Bacteria

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Adeleh Sobhanipour

2017-01-01

Full Text Available The occurrence of antibiotic-resistant pathogenic bacteria is becoming a serious problem. The rise of multiresistance strains has forced the pharmaceutical industry to come up with new generation of more effective and potent antibiotics, therefore creating development of antivirulence compounds. Due to extensive usage of cell-to-cell bacterial communication (QS systems to monitor the production of virulence factors, disruption of QS system results in creation of a promising strategy for the control of bacterial infection. Numerous natural quorum quenching (QQ agents have been identified. In addition, many microorganisms are capable of producing smaller molecular QS inhibitors and/or macromolecular QQ enzymes. In present survey, anti QS activity of 1280 rhizosphere bacteria was assessed using the Pectobacterium carotovorum as AHL-donor and Chromobacterium violaceum CV026 as biosensor system. The results showed that 61 strains had highly AHL-degrading activity. Both Lux I and Lux R activity were affected by some isolates, suggesting that the rhizobacteria target both QS signal and receptor. These soil microorganisms with their anti-QS activity have the potential to be novel therapeutic agents for reducing virulence and pathogenicity of antibiotic resistant bacteria.

Cell Adhesion Molecules of the Immunoglobulin Superfamily in the Nervous System

DEFF Research Database (Denmark)

Walmod, Peter Schledermann; Pedersen, Martin Volmer; Berezin, Vladimir

2007-01-01

Cell adhesion molecules (CAMs) are proteins mediating cell-cell or cell-extracellular matrix (ECM) interactions. CAMs are traditionally divided into four groups, the cadherins, the selectins, the integrins and CAMs belonging to the immunoglobulin superfamily (IgSF). The present chapter describes...... CAMs belonging to IgSF, that exclusively or in part, are expressed in the nervous system. The chapter includes descriptions of myelin protein zero (P0), integrin-associated protein (CD47), neuroplastin, activated leukocyte-cell adhesion molecule (ALCAM), melanoma cell adhesion molecule (MCAM......), myelinassociated glycoprotein (MAG), the neural cell adhesion molecules 1 and 2 (NCAM, NCAM2), Down Syndrome cell adhesion molecule (DSCAM) and Down Syndrome cell adhesion molecule-like-1 (DSCAML1), sidekick 1 and 2 (SDK1, SDK2), signal-regulatory proteins (SIRPs), nectins, nectin-like proteins (necls...

Thyroid Hormone Supplementation Restores Spatial Memory, Hippocampal Markers of Neuroinflammation, Plasticity-Related Signaling Molecules, and β-Amyloid Peptide Load in Hypothyroid Rats.

Science.gov (United States)

Chaalal, Amina; Poirier, Roseline; Blum, David; Laroche, Serge; Enderlin, Valérie

2018-05-23

Hypothyroidism is a condition that becomes more prevalent with age. Patients with untreated hypothyroidism have consistently reported symptoms of severe cognitive impairments. In patients suffering hypothyroidism, thyroid hormone supplementation offers the prospect to alleviate the cognitive consequences of hypothyroidism; however, the therapeutic value of TH supplementation remains at present uncertain and the link between cellular modifications associated with hypothyroidism and neurodegeneration remains to be elucidated. In the present study, we therefore evaluated the molecular and behavioral consequences of T3 hormone replacement in an animal model of hypothyroidism. We have previously reported that the antithyroid molecule propylthiouracil (PTU) given in the drinking water favors cerebral atrophy, brain neuroinflammation, Aβ production, Tau hyperphosphorylation, and altered plasticity-related cell-signaling pathways in the hippocampus in association with hippocampal-dependent spatial memory deficits. In the present study, our aim was to explore, in this model, the effect of hippocampal T3 signaling normalization on various molecular mechanisms involved in learning and memory that goes awry under conditions of hypothyroidism and to evaluate its potential for recovery of hippocampal-dependent memory deficits. We report that T3 supplementation can alleviate hippocampal-dependent memory impairments displayed by hypothyroid rats and normalize key markers of thyroid status in the hippocampus, of neuroinflammation, Aβ production, and of cell-signaling pathways known to be involved in synaptic plasticity and memory function. Together, these findings suggest that normalization of hippocampal T3 signaling is sufficient to reverse molecular and cognitive dysfunctions associated with hypothyroidism.

Single-molecule dataset (SMD): a generalized storage format for raw and processed single-molecule data.

Science.gov (United States)

Greenfeld, Max; van de Meent, Jan-Willem; Pavlichin, Dmitri S; Mabuchi, Hideo; Wiggins, Chris H; Gonzalez, Ruben L; Herschlag, Daniel

2015-01-16

Single-molecule techniques have emerged as incisive approaches for addressing a wide range of questions arising in contemporary biological research [Trends Biochem Sci 38:30-37, 2013; Nat Rev Genet 14:9-22, 2013; Curr Opin Struct Biol 2014, 28C:112-121; Annu Rev Biophys 43:19-39, 2014]. The analysis and interpretation of raw single-molecule data benefits greatly from the ongoing development of sophisticated statistical analysis tools that enable accurate inference at the low signal-to-noise ratios frequently associated with these measurements. While a number of groups have released analysis toolkits as open source software [J Phys Chem B 114:5386-5403, 2010; Biophys J 79:1915-1927, 2000; Biophys J 91:1941-1951, 2006; Biophys J 79:1928-1944, 2000; Biophys J 86:4015-4029, 2004; Biophys J 97:3196-3205, 2009; PLoS One 7:e30024, 2012; BMC Bioinformatics 288 11(8):S2, 2010; Biophys J 106:1327-1337, 2014; Proc Int Conf Mach Learn 28:361-369, 2013], it remains difficult to compare analysis for experiments performed in different labs due to a lack of standardization. Here we propose a standardized single-molecule dataset (SMD) file format. SMD is designed to accommodate a wide variety of computer programming languages, single-molecule techniques, and analysis strategies. To facilitate adoption of this format we have made two existing data analysis packages that are used for single-molecule analysis compatible with this format. Adoption of a common, standard data file format for sharing raw single-molecule data and analysis outcomes is a critical step for the emerging and powerful single-molecule field, which will benefit both sophisticated users and non-specialists by allowing standardized, transparent, and reproducible analysis practices.

Divulgación on-line de los códigos de buen gobierno en las IES y su determinación para el posicionamiento en el ranking QS

OpenAIRE

Méndez Beltrán, Jairo Andrés

2015-01-01

Dado el interés que se presenta con los temas de gobierno corporativo, este trabajo busca describir si la divulgación on-line de los contenidos de los códigos de buen gobierno, es determinante en el posicionamiento que tienen las Instituciones de Educación Superior (IES) en el ranking QS. Partiendo de una muestra de 20 IES, se recolectaron un conjunto de datos dicotómicos para 30 variables independientes y se relacionaron con la variable dependiente denominada posicionamiento en el ranking. A...

[Formation of the Pseudomonas aeruginosa PAO1 biofilms in the presence of hydrogen peroxide; the effect of the AiiA gene].

Science.gov (United States)

Pliuta, V A; Andreenko, Iu V; Kuznetsov, A E; Khmel', I A

2013-01-01

In the natural ecosystems, most bacteria exist as specifically organized biofilms attached to various surfaces; the biofilms have a complex architecture and are surrounded by an exopolymeric matrix. The bacteria in the biofilms are extremely resistant to antibacterial agents. The ability of the pathogenic bacteria to produce biofilms causes serious problems in medicine. Therefore, the study of the action of different compounds with antibacterial activity is of great interest. In this work, we studied the effect of the hydrogen peroxide (H2O2) on the formation of biofilms by Pseudomonas aeruginosa PAO1. It was shown that H2O2 in concentrations that do not suppress bacterial growth (or suppress it only weakly) stimulates the formation of the biofilms. At higher concentrations, H2O2 inhibits the formation of the biofilms. In order to determine if the stimulation of the biofilm formation depends on Quorum Sensing (QS) regulation, the plasmid pME6863 containing the heterologous gene aiiA encoding the N-acyl-homoserine lactonase AiiA was introduced into P. aeruginosa PAO1. The synthesis by cells of this enzyme degrading N-acyl-homoserine lactones (AHL), signaling molecules of the QS systems, led to the absence of the stimulation of the biofilm formation by the action of H2O2. This fact indicates that the stimulation of the biofilm formation in the presence of H2O2 depends on the functioning of the QS systems of the gene expression regulation of P. aeruginosa PAO1.

A small diffusible signal molecule is responsible for the global control of virulence and exoenzyme production in the plant pathogen Erwinia carotovora.

Science.gov (United States)

Pirhonen, M; Flego, D; Heikinheimo, R; Palva, E T

1993-06-01

Virulence of the plant pathogen Erwinia carotovora subsp. carotovora is dependent on the production and secretion of a complex arsenal of plant cell wall-degrading enzymes. Production of these exoenzymes is controlled by a global regulatory mechanism. A virulent mutants in one of the regulatory loci, expI, show a pleiotropic defect in the growth phase-dependent transcriptional activation of exoenzyme gene expression. The expI gene encodes a 26 kDa polypeptide that is structurally and functionally related to the luxI gene product of Vibrio fischeri. Functional similarity of expI and luxI has been demonstrated by reciprocal genetic complementation experiments. LuxI controls bioluminescence in V.fischeri in a growth phase-dependent manner by directing the synthesis of the diffusible autoinducer, N-(3-oxohexanoyl) homoserine lactone. E.c. subsp. carotovora expI+ strains or Escherichia coli harboring the cloned expI gene excrete a small diffusible signal molecule that complements the expI mutation of Erwinia as well as a luxI mutation of V.fischeri. This extracellular complementation can also be achieved by E.coli harboring the luxI gene from V.fischeri or by adding the synthetic V.fischeri autoinducer. Both the production of the plant tissue-macerating exoenzymes and the ability of the bacteria to propagate in planta are restored in expI mutants by autoinducer addition. These data suggest that the same signal molecule is employed in control of such diverse processes as virulence in a plant pathogen and bioluminescence in a marine bacterium, and may represent a general mechanism by which bacteria modulate gene expression in response to changing environmental conditions.

Extracellular signaling and multicellularity in Bacillus subtilis.

Science.gov (United States)

Shank, Elizabeth Anne; Kolter, Roberto

2011-12-01

Bacillus subtilis regulates its ability to differentiate into distinct, co-existing cell types in response to extracellular signaling molecules produced either by itself, or present in its environment. The production of molecules by B. subtilis cells, as well as their response to these signals, is not uniform across the population. There is specificity and heterogeneity both within genetically identical populations as well as at the strain-level and species-level. This review will discuss how extracellular signaling compounds influence B. subtilis multicellularity with regard to matrix-producing cannibal differentiation, germination, and swarming behavior, as well as the specificity of the quorum-sensing peptides ComX and CSF. It will also highlight how imaging mass spectrometry can aid in identifying signaling compounds and contribute to our understanding of the functional relationship between such compounds and multicellular behavior. Copyright © 2011 Elsevier Ltd. All rights reserved.

[Controlling effect of bushen huatan compound on the insulin signal conducting molecule inside ovaries in polycystic ovary syndrome model rats].

Science.gov (United States)

Liang, Chen; Cong, Jing; Chang, Hui

2011-12-01

To study the effects of Bushen Huatan Compound (BHC) on the glycolipid metabolism and the expressions of the insulin signal conducting molecules inside ovaries in polycystic ovary syndrome (PCOS) model rats. Female Wistar rats were subcutaneously injected with 2.5 mg/kg testosterone propionate (Their female offspring were randomly divided into the medication group and the model group, 10 in each.) or neutral tea oil of the same dose (Ten female offspring was taken as the control group.) on the 16th day of pregnancy, once daily, for 3 successive days. BHC was given to rats in the medication group by gastrogavage, while equal volume of distilled water was given to rats in the model group and the control group by gastrogavage, both once daily for 20 successive days. The body weight and ovary weight were weighed to calculate the ratio of wet fat weight/body weight. The blood glucose levels were detected at 0, 0.5, 1, and 2 h using oral glucose tolerance test (OGTT). The serum concentrations of high-density lipoprotein cholesterol (HDL-C), triglyceride (TG), fasting blood glucose (FBG), and insulin were detected to calculate homeostasis model assessment of insulin resistance (HOMA-IR). The expressions of protein kinase B (AKT2), glycogen synthase kinase-3beta (GSK3beta), glucose transporter-4 (GLUT4), extracellular signal regulated kinase-1 (ERK1) protein, P-AKT2, P-GSK3beta, and P-ERK1 in ovaries were detected using Western blot. Compared with the control group, the ratio of wet fat weight/ body weight, the blood glucose levels at 0.5 and 2 h in OGTT, and HOMA-IR all obviously increased, and the HDL-C level obviously decreased in the model group (P < 0.05). Compared with the model group, the ratio of wet fat weight/body weight and the blood glucose levels at 2 h in OGTT obviously decreased, and the HDL-C level obviously increased in the medication group (P < 0.05). The expressions of AKT2, P-AKT2, GSK3beta, P-GSK3beta, GLUT4, and ERK1 in the ovary tissue were obviously

VanT, a central regulator of quorum sensing signalling in Vibrio anguillarum

OpenAIRE

Croxatto, Antony

2006-01-01

Many bacteria produce signal molecules that serve in a cell-to-cell communication system termed quorum sensing. This signalling system allows a bacterial population to co-ordinately regulate functions according to their cell number in a defined environment. As bacterial growth progresses towards the stationary phase, signalling molecules accumulate in the growth medium and, above a certain threshold level, regulate the expression of genes involved in diverse functions. Most of the functions m...

Comparative efficacy of benthic biotic indices in assessing the Ecological Quality Status (EcoQS) of the stressed Ulhas estuary, India.

Science.gov (United States)

Mulik, Jyoti; Sukumaran, Soniya; Srinivas, Tatiparthi; Vijapure, Tejal

2017-07-15

Ecostatus of Ulhas estuary, one of the most polluted estuaries along the industrialized and urbanized northwest coast of India, was evaluated by six widely accepted benthic indices viz. H'(log 2 ), AMBI, M-AMBI, BENTIX, BOPA and BO2A to test their efficiency in a tropical setting. The mesohaline zone, which presented eutrophic conditions, was classified as 'bad' by all indices due to the azoic status. Despite significant correlations obtained between indices, there were discrepancies in the accurate level of EcoQS assigned to each station. AMBI was observed to be most efficient in indicating a clear spatial variability from a 'poor' to 'bad' ecological quality status in the middle and upstream zones to an improved status in the downstream region. Limitations of all indices are discussed in light of their suitability for assessing the estuarine environmental condition. The present results could provide a fillip to environmental improvement initiatives currently being undertaken in the estuary. Copyright © 2017 Elsevier Ltd. All rights reserved.

Identification of small molecules that disrupt signaling between ABL and its positive regulator RIN1.

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Pamela Y Ting

Full Text Available Constitutively active BCR-ABL kinase fusions are causative mutations in the pathogenesis of hematopoietic neoplasias including chronic myelogenous leukemia (CML. Although these fusions have been successfully targeted with kinase inhibitors, drug-resistance and relapse continue to limit long-term survival, highlighting the need for continued innovative drug discovery. We developed a time-resolved Förster resonance energy transfer (TR-FRET -based assay to identify compounds that disrupt stimulation of the ABL kinase by blocking its ability to bind the positive regulator RIN1. This assay was used in a high throughput screen (HTS of two small molecule libraries totaling 444,743 compounds. 708 confirmed hits were counter-screened to eliminate off-target inhibitors and reanalyzed to prioritize compounds with IC50 values below 10 μM. The CML cell line K562 was then used to identify five compounds that decrease MAPK1/3 phosphorylation, which we determined to be an indicator of RIN1-dependent ABL signaling. One of these compounds is a thiadiazole, and the other four are structurally related acyl piperidine amides. Notably, these five compounds lower cellular BCR-ABL1 kinase activity by blocking a positive regulatory interaction rather than directly inhibiting ABL catalytic function.

RpoN Modulates Carbapenem Tolerance in Pseudomonas aeruginosa through Pseudomonas Quinolone Signal and PqsE

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Murakami, Keiji; Amoh, Takashi; Ono, Tsuneko; Miyake, Yoichiro

2016-01-01

The ability of Pseudomonas aeruginosa to rapidly modulate its response to antibiotic stress and persist in the presence of antibiotics is closely associated with the process of cell-to-cell signaling. The alternative sigma factor RpoN (σ54) is involved in the regulation of quorum sensing (QS) and plays an important role in the survival of stationary-phase cells in the presence of carbapenems. Here, we demonstrate that a ΔrpoN mutant grown in nutrient-rich medium has increased expression of pqsA, pqsH, and pqsR throughout growth, resulting in the increased production of the Pseudomonas quinolone signal (PQS). The link between pqsA and its role in carbapenem tolerance was studied using a ΔrpoN ΔpqsA mutant, in which the carbapenem-tolerant phenotype of the ΔrpoN mutant was abolished. In addition, we demonstrate that another mechanism leading to carbapenem tolerance in the ΔrpoN mutant is mediated through pqsE. Exogenously supplied PQS abolished the biapenem-sensitive phenotype of the ΔrpoN ΔpqsA mutant, and overexpression of pqsE failed to alter the susceptibility of the ΔrpoN ΔpqsA mutant to biapenem. The mutations in the ΔrpoN ΔrhlR mutant and the ΔrpoN ΔpqsH mutant led to susceptibility to biapenem. Comparison of the changes in the expression of the genes involved in QS in wild-type PAO1 with their expression in the ΔrpoN mutant and the ΔrpoN mutant-derived strains demonstrated the regulatory effect of RpoN on the transcript levels of rhlR, vqsR, and rpoS. The findings of this study demonstrate that RpoN negatively regulates the expression of PQS in nutrient-rich medium and provide evidence that RpoN interacts with pqsA, pqsE, pqsH, and rhlR in response to antibiotic stress. PMID:27431228

Inhibitor of PI3K/Akt Signaling Pathway Small Molecule Promotes Motor Neuron Differentiation of Human Endometrial Stem Cells Cultured on Electrospun Biocomposite Polycaprolactone/Collagen Scaffolds.

Science.gov (United States)

Ebrahimi-Barough, Somayeh; Hoveizi, Elham; Yazdankhah, Meysam; Ai, Jafar; Khakbiz, Mehrdad; Faghihi, Faezeh; Tajerian, Roksana; Bayat, Neda

2017-05-01

Small molecules as useful chemical tools can affect cell differentiation and even change cell fate. It is demonstrated that LY294002, a small molecule inhibitor of phosphatidylinositol 3-kinase (PI3K)/Akt signal pathway, can inhibit proliferation and promote neuronal differentiation of mesenchymal stem cells (MSCs). The purpose of this study was to investigate the differentiation effect of Ly294002 small molecule on the human endometrial stem cells (hEnSCs) into motor neuron-like cells on polycaprolactone (PCL)/collagen scaffolds. hEnSCs were cultured in a neurogenic inductive medium containing 1 μM LY294002 on the surface of PCL/collagen electrospun fibrous scaffolds. Cell attachment and viability of cells on scaffolds were characterized by scanning electron microscope (SEM) and 3-(4,5-dimethylthiazoyl-2-yl)2,5-diphenyltetrazolium bromide (MTT) assay. The expression of neuron-specific markers was assayed by real-time PCR and immunocytochemistry analysis after 15 days post induction. Results showed that attachment and differentiation of hEnSCs into motor neuron-like cells on the scaffolds with Ly294002 small molecule were higher than that of the cells on tissue culture plates as control group. In conclusion, PCL/collagen electrospun scaffolds with Ly294002 have potential for being used in neural tissue engineering because of its bioactive and three-dimensional structure which enhances viability and differentiation of hEnSCs into neurons through inhibition of the PI3K/Akt pathway. Thus, manipulation of this pathway by small molecules can enhance neural differentiation.

A novel role for small molecule glycomimetics in the protection against lipid-induced endothelial dysfunction: Involvement of Akt/eNOS and Nrf2/ARE signaling.

Science.gov (United States)

Mahmoud, Ayman M; Wilkinson, Fiona L; Jones, Alan M; Wilkinson, James A; Romero, Miguel; Duarte, Juan; Alexander, M Yvonne

2017-01-01

Glycomimetics are a diverse array of saccharide-inspired compounds, designed to mimic the bioactive functions of glycosaminoglycans. Therefore, glycomimetics represent a unique source of novel therapies to target aberrant signaling and protein interactions in a wide range of diseases. We investigated the protective effects of four newly synthesized small molecule glycomimetics against lipid-induced endothelial dysfunction, with an emphasis on nitric oxide (NO) and oxidative stress. Four aromatic sugar mimetics were synthesized by the stepwise transformation of 2,5-dihydroxybenzoic acid to derivatives (C1-C4) incorporating sulfate groups to mimic the structure of heparan sulfate. Glycomimetic-treated human umbilical vein endothelial cells (HUVECs) were exposed to palmitic acid to model lipid-induced oxidative stress. Palmitate-induced impairment of NO production was restored by the glycomimetics, through activation of Akt/eNOS signaling. Furthermore, C1-C4 significantly inhibited palmitate-induced reactive oxygen species (ROS) production, lipid peroxidation, and activity and expression of NADPH oxidase. These effects were attributed to activation of the Nrf2/ARE pathway and downstream activation of cellular antioxidant and cytoprotective proteins. In ex vivo vascular reactivity studies, the glycomimetics (C1-C4) also demonstrated a significant improvement in endothelium-dependent relaxation and decreased ROS production and NADPH oxidase activity in isolated mouse thoracic aortic rings exposed to palmitate. The small molecule glycomimetics, C1-C4, protect against lipid-induced endothelial dysfunction through up-regulation of Akt/eNOS and Nrf2/ARE signaling pathways. Thus, carbohydrate-derived therapeutics are a new class of glycomimetic drugs targeting endothelial dysfunction, regarded as the first line of defense against vascular complications in cardiovascular disease. Copyright © 2016 Elsevier B.V. All rights reserved.

New small molecule inhibitors of UPR activation demonstrate that PERK, but not IRE1α signaling is essential for promoting adaptation and survival to hypoxia

International Nuclear Information System (INIS)

Cojocari, Dan; Vellanki, Ravi N.; Sit, Brandon; Uehling, David; Koritzinsky, Marianne; Wouters, Bradly G.

2013-01-01

Background and purpose: The unfolded protein response (UPR) is activated in response to hypoxia-induced stress in the endoplasmic reticulum (ER) and consists of three distinct signaling arms. Here we explore the potential of targeting two of these arms with new potent small-molecule inhibitors designed against IRE1α and PERK. Methods: We utilized shRNAs and small-molecule inhibitors of IRE1α (4μ8c) and PERK (GSK-compound 39). XBP1 splicing and DNAJB9 mRNA was measured by qPCR and was used to monitor IRE1α activity. PERK activity was monitored by immunoblotting eIF2α phosphorylation and qPCR of DDIT3 mRNA. Hypoxia tolerance was measured using proliferation and clonogenic cell survival assays of cells exposed to mild or severe hypoxia in the presence of the inhibitors. Results: Using knockdown experiments we show that PERK is essential for survival of KP4 cells while knockdown of IRE1α dramatically decreases the proliferation and survival of HCT116 during hypoxia. Further, we show that in response to both hypoxia and other ER stress-inducing agents both 4μ8c and the PERK inhibitor are selective and potent inhibitors of IRE1α and PERK activation, respectively. However, despite potent inhibition of IRE1α activation, 4μ8c had no effect on cell proliferation or clonogenic survival of cells exposed to hypoxia. This was in contrast to the inactivation of PERK signaling with the PERK inhibitor, which reduced tolerance to hypoxia and other ER stress inducing agents. Conclusions: Our results demonstrate that IRE1α but not its splicing activity is important for hypoxic cell survival. The PERK signaling arm is uniquely important for promoting adaptation and survival during hypoxia-induced ER stress and should be the focus of future therapeutic efforts

Phosphoproteomics-based systems analysis of signal transduction networks

Directory of Open Access Journals (Sweden)

Hiroko eKozuka-Hata

2012-01-01

Full Text Available Signal transduction systems coordinate complex cellular information to regulate biological events such as cell proliferation and differentiation. Although the accumulating evidence on widespread association of signaling molecules has revealed essential contribution of phosphorylation-dependent interaction networks to cellular regulation, their dynamic behavior is mostly yet to be analyzed. Recent technological advances regarding mass spectrometry-based quantitative proteomics have enabled us to describe the comprehensive status of phosphorylated molecules in a time-resolved manner. Computational analyses based on the phosphoproteome dynamics accelerate generation of novel methodologies for mathematical analysis of cellular signaling. Phosphoproteomics-based numerical modeling can be used to evaluate regulatory network elements from a statistical point of view. Integration with transcriptome dynamics also uncovers regulatory hubs at the transcriptional level. These omics-based computational methodologies, which have firstly been applied to representative signaling systems such as the epidermal growth factor receptor pathway, have now opened up a gate for systems analysis of signaling networks involved in immune response and cancer.

Sensing single electrons with single molecules

International Nuclear Information System (INIS)

Plakhotnik, Taras

2007-01-01

We propose a new methodology for probing transport of just one electron, a process of great importance both in nature and in artificial devices. Our idea for locating a single electron is analogues to the conventional GPS where signals from several satellites are used to locate a macro object. Using fluorescent molecules as tiny sensors, it is possible to determine 3D displacement vector of an electron

Cell Adhesion Molecules and Ubiquitination—Functions and Significance

Science.gov (United States)

Homrich, Mirka; Gotthard, Ingo; Wobst, Hilke; Diestel, Simone

2015-01-01

Cell adhesion molecules of the immunoglobulin (Ig) superfamily represent the biggest group of cell adhesion molecules. They have been analyzed since approximately 40 years ago and most of them have been shown to play a role in tumor progression and in the nervous system. All members of the Ig superfamily are intensively posttranslationally modified. However, many aspects of their cellular functions are not yet known. Since a few years ago it is known that some of the Ig superfamily members are modified by ubiquitin. Ubiquitination has classically been described as a proteasomal degradation signal but during the last years it became obvious that it can regulate many other processes including internalization of cell surface molecules and lysosomal sorting. The purpose of this review is to summarize the current knowledge about the ubiquitination of cell adhesion molecules of the Ig superfamily and to discuss its potential physiological roles in tumorigenesis and in the nervous system. PMID:26703751

Communication: atomic force detection of single-molecule nonlinear optical vibrational spectroscopy.

Science.gov (United States)

Saurabh, Prasoon; Mukamel, Shaul

2014-04-28

Atomic Force Microscopy (AFM) allows for a highly sensitive detection of spectroscopic signals. This has been first demonstrated for NMR of a single molecule and recently extended to stimulated Raman in the optical regime. We theoretically investigate the use of optical forces to detect time and frequency domain nonlinear optical signals. We show that, with proper phase matching, the AFM-detected signals closely resemble coherent heterodyne-detected signals. Applications are made to AFM-detected and heterodyne-detected vibrational resonances in Coherent Anti-Stokes Raman Spectroscopy (χ((3))) and sum or difference frequency generation (χ((2))).

Lipid rafts and B cell signaling.

Science.gov (United States)

Gupta, Neetu; DeFranco, Anthony L

2007-10-01

B cells comprise an essential component of the humoral immune system. They are equipped with the unique ability to synthesize and secrete pathogen-neutralizing antibodies, and share with professional antigen presenting cells the ability to internalize foreign antigens, and process them for presentation to helper T cells. Recent evidence indicates that specialized cholesterol- and glycosphingolipid-rich microdomains in the plasma membrane commonly referred to as lipid rafts, serve to compartmentalize key signaling molecules during the different stages of B cell activation including B cell antigen receptor (BCR)-initiated signal transduction, endocytosis of BCR-antigen complexes, loading of antigenic peptides onto MHC class II molecules, MHC-II associated antigen presentation to helper T cells, and receipt of helper signals via the CD40 receptor. Here we review the recent literature arguing for a role of lipid rafts in the spatial organization of B cell function.

New developments in microbial interspecies signaling.

Science.gov (United States)

Shank, Elizabeth Anne; Kolter, Roberto

2009-04-01

There is a growing appreciation that in addition to well-documented intraspecies quorum sensing systems, small molecules act as signals between microbes of different species. This review will focus on how bacterial small molecules modulate these interspecies interactions. We will particularly emphasize complex relationships such as those between microbes and insects, interactions resulting in non-antagonistic outcomes (i.e. developmental and morphological processes), how co-culture can lead to the discovery of new small molecules, and the use of known compounds to evoke unexpected responses and mediate crosstalk between microbes.

Enhanced NMR signal detection of imino protons in RNA molecules containing 3' dangling nucleotides

International Nuclear Information System (INIS)

Amborski, Andrew N.; Johnson, Philip E.

2008-01-01

We present a method for improving the quality of nuclear magnetic resonance (NMR) spectra involving exchangeable protons near the base of the stem of RNA hairpin molecules. NMR spectra of five different RNA hairpins were compared. These hairpins consisted of a native RNA structure and four molecules each having different unpaired, or dangling, nucleotides at the 3' end. NMR experiments were acquired in water for each construct and the quality of the imino proton spectral regions were examined. The imino resonances near the base of the stem of the wild type RNA structure were not observed due to breathing motions. However, a significant increase in spectral quality for molecules with dangling 3' adenosine or guanosine nucleotides was observed, with imino protons detected in these constructs that were not observed in the wild type construct. A modest improvement in spectral quality was seen for the construct with a 3' unpaired uridine, whereas no significant improvement was observed for a 3' unpaired cytidine. This improvement in NMR spectral quality mirrors the increased thermodynamic stability observed for 3' unpaired nucleotides which is dependant on the stacking interactions of these nucleotides against the base of the stem. The use of a dangling 3' adenosine nucleotide represents an easy method to significantly improve the quality of NMR spectra of RNA molecules

Lactation Biology Symposium: Lactocrine signaling and developmental programming

Science.gov (United States)

Lactocrine signaling is defined as transmission of bioactive factors from mother to offspring as a consequence of nursing. Lactocrine transmission of signaling molecules may be an evolutionarily conserved process through which bioactive factors necessary for support of neonatal development are deliv...

NADPH oxidase and lipid raft-associated redox signaling are required for PCB153-induced upregulation of cell adhesion molecules in human brain endothelial cells

International Nuclear Information System (INIS)

Eum, Sung Yong; Andras, Ibolya; Hennig, Bernhard; Toborek, Michal

2009-01-01

Exposure to persistent organic pollutants, such as polychlorinated biphenyls (PCBs), can lead to chronic inflammation and the development of vascular diseases. Because cell adhesion molecules (CAMs) of the cerebrovascular endothelium regulate infiltration of inflammatory cells into the brain, we have explored the molecular mechanisms by which ortho-substituted polychlorinated biphenyls (PCBs), such as PCB153, can upregulate CAMs in brain endothelial cells. Exposure to PCB153 increased expression of intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1), as well as elevated adhesion of leukocytes to brain endothelial cells. These effects were impeded by inhibitors of EGFR, JAKs, or Src activity. In addition, pharmacological inhibition of NADPH oxidase or disruption of lipid rafts by cholesterol depleting agents blocked PCB153-induced phosphorylation of JAK and Src kinases and upregulation of CAMs. In contrast, silencing of caveolin-1 by siRNA interference did not affect upregulation of ICAM-1 and VCAM-1 in brain endothelial cells stimulated by PCB153. Results of the present study indicate that lipid raft-dependent NADPH oxidase/JAK/EGFR signaling mechanisms regulate the expression of CAMs in brain endothelial cells and adhesion of leukocytes to endothelial monolayers. Due to its role in leukocyte infiltration, induction of CAMs may contribute to PCB-induced cerebrovascular disorders and neurotoxic effects in the CNS.

Why do bacteria regulate public goods by quorum sensing? - How the shapes of cost and benefit functions determine the form of optimal regulation

Directory of Open Access Journals (Sweden)

Silja eHeilmann

2015-07-01

Full Text Available Many bacteria secrete compounds, which act as public goods. Such compounds are often under quorum sensing (QS regulation, yet it is not understood exactly when bacteria may gain from having a public good under QS regulation.Here, we show that the optimal public good production rate per cell as a function of population size (the optimal production curve, OPC depend crucially on the cost and benefit functions of the public good and that the OPC will fall into one of two categories: Either it is continuous or it jumps from zero discontinuously at a critical population size.If, e.g., the public good has accelerating returns and linear cost, then the OPC is discontinuous and the best strategy thus to ramp up production sharply at a precise population size.By using the example of public goods with accelerating and diminishing returns (and linear cost we are able to determine how the two different categories of OPSs, can best be matched by production regulated through a QS signal feeding back on its own production. We find that the optimal QS parameters are different for the two categories and specifically that public goods, which provide accelerating returns, call for stronger positive signal feedback.

Detection of Individual Molecules and Ions by Carbon Nanotube-Based Differential Resistive Pulse Sensor.

Science.gov (United States)

Peng, Ran; Tang, Xiaowu Shirley; Li, Dongqing

2018-04-01

This paper presents a new method of sensing single molecules and cations by a carbon nanotube (CNT)-based differential resistive pulse sensing (RPS) technique on a nanofluidic chip. A mathematical model for multichannel RPS systems is developed to evaluate the CNT-based RPS signals. Individual cations, rhodamine B dye molecules, and ssDNAs are detected successfully with high resolution and high signal-to-noise ratio. Differentiating ssDNAs with 15 and 30 nucleotides are achieved. The experimental results also show that translocation of negatively charged ssDNAs through a CNT decreases the electrical resistance of the CNT channel, while translocation of positively charged cations and rhodamine B molecules increases the electrical resistance of the CNT. The CNT-based nanofluidic device developed in this work provides a new avenue for single-molecule/ion detection and offers a potential strategy for DNA sequencing. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Salicylic acid signaling inhibits apoplastic reactive oxygen species signaling.

Science.gov (United States)

Xu, Enjun; Brosché, Mikael

2014-06-04

Reactive oxygen species (ROS) are used by plants as signaling molecules during stress and development. Given the amount of possible challenges a plant face from their environment, plants need to activate and prioritize between potentially conflicting defense signaling pathways. Until recently, most studies on signal interactions have focused on phytohormone interaction, such as the antagonistic relationship between salicylic acid (SA)-jasmonic acid and cytokinin-auxin. In this study, we report an antagonistic interaction between SA signaling and apoplastic ROS signaling. Treatment with ozone (O3) leads to a ROS burst in the apoplast and induces extensive changes in gene expression and elevation of defense hormones. However, Arabidopsis thaliana dnd1 (defense no death1) exhibited an attenuated response to O3. In addition, the dnd1 mutant displayed constitutive expression of defense genes and spontaneous cell death. To determine the exact process which blocks the apoplastic ROS signaling, double and triple mutants involved in various signaling pathway were generated in dnd1 background. Simultaneous elimination of SA-dependent and SA-independent signaling components from dnd1 restored its responsiveness to O3. Conversely, pre-treatment of plants with SA or using mutants that constitutively activate SA signaling led to an attenuation of changes in gene expression elicited by O3. Based upon these findings, we conclude that plants are able to prioritize the response between ROS and SA via an antagonistic action of SA and SA signaling on apoplastic ROS signaling.

Compact quantum dots for single-molecule imaging.

Science.gov (United States)

Smith, Andrew M; Nie, Shuming

2012-10-09

Single-molecule imaging is an important tool for understanding the mechanisms of biomolecular function and for visualizing the spatial and temporal heterogeneity of molecular behaviors that underlie cellular biology (1-4). To image an individual molecule of interest, it is typically conjugated to a fluorescent tag (dye, protein, bead, or quantum dot) and observed with epifluorescence or total internal reflection fluorescence (TIRF) microscopy. While dyes and fluorescent proteins have been the mainstay of fluorescence imaging for decades, their fluorescence is unstable under high photon fluxes necessary to observe individual molecules, yielding only a few seconds of observation before complete loss of signal. Latex beads and dye-labeled beads provide improved signal stability but at the expense of drastically larger hydrodynamic size, which can deleteriously alter the diffusion and behavior of the molecule under study. Quantum dots (QDs) offer a balance between these two problematic regimes. These nanoparticles are composed of semiconductor materials and can be engineered with a hydrodynamically compact size with exceptional resistance to photodegradation (5). Thus in recent years QDs have been instrumental in enabling long-term observation of complex macromolecular behavior on the single molecule level. However these particles have still been found to exhibit impaired diffusion in crowded molecular environments such as the cellular cytoplasm and the neuronal synaptic cleft, where their sizes are still too large (4,6,7). Recently we have engineered the cores and surface coatings of QDs for minimized hydrodynamic size, while balancing offsets to colloidal stability, photostability, brightness, and nonspecific binding that have hindered the utility of compact QDs in the past (8,9). The goal of this article is to demonstrate the synthesis, modification, and characterization of these optimized nanocrystals, composed of an alloyed HgxCd1-xSe core coated with an

Tyrosine kinase signalling in breast cancer

International Nuclear Information System (INIS)

Hynes, Nancy E

2000-01-01

Cells are continuously exposed to diverse stimuli ranging from soluble endocrine and paracrine factors to signalling molecules on neighbouring cells. Receptors of the tyrosine kinase family play an important role in the integration and interpretation of these external stimuli, allowing a cell to respond appropriately to its environment. The activation of receptor tyrosine kinases (RTKs) is tightly controlled, allowing a normal cell to correctly integrate its external environment with internal signal transduction pathways. In contrast, due to numerous molecular alterations arising during the course of malignancy, a tumour is characterized by an abnormal response to its environment, which allows cancer cells to evade the normal mechanisms controlling cellular proliferation. Alterations in the expression of various RTKs, in their activation, and in the signalling molecules lying downstream of the receptors play important roles in the development of cancer. This topic is the major focus of the thematic review section of this issue of Breast Cancer Research

Cell biology symposium: Membrane trafficking and signal transduction

Science.gov (United States)

In general, membrane trafficking is a broad group of processes where proteins and other large molecules are distributed throughout the cell as well as adjacent extracellular spaces. Whereas signal transduction is a process where signals are transmitted through a series of chemical or molecular event...

Proanthocyanidins-Will they effectively restrain conspicuous bacterial strains devolving on urinary tract infection?

Science.gov (United States)

Jagannathan, Venkataseshan; Viswanathan, Pragasam

2018-05-18

Struvite or infection stones are one of the major clinical burdens among urinary tract infection, which occur due to the interaction between microbes and urine mineral components. Numerous urinary tract infection (UTI) causing microbes regulate through biofilm formation for survival from host defense, it is often found difficult in its eradication with simple anti-microbial agents and also the chance of recurrence and resistance development is significantly high. Cranberry consumption and maintenance of urinary tract health have been supported by clinical, epidemiological, and mechanistic studies. It predominantly contains proanthocyanidins that belong to the class of polyphenols with repeating catechin and epicatechin monomeric units. Numerous studies have correlated proanthocyanidin consumption and prevention of bacterial adhesion to uroepithelial cells. Quorum sensing (QS) is the prime mechanism that drives bacteria to coordinate biofilm development and virulence expression. Reports have shown that proanthocyanidins are effective in disrupting cell-cell communication by quenching signal molecules. Overall, this review assesses the merits of proanthocyanidins and its effective oppression on adherence, motility, QS, and biofilm formation of major UTI strains such as Escherichia coli, Pseudomonas aeruginosa, and Proteus mirabilis by comparing and evaluating results from many significant findings. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

New compositions of cadmium selenium nanoparticles and dye molecules with cyclodextrin inclusion complexes

International Nuclear Information System (INIS)

Asimov, M.M.; Anufrik, S.S.; Tarkovsky, V.V.; Sazonko, H.H.

2013-01-01

Spectroscopic properties of new heterogeneous multicolor compositions based on cadmium selenium (CdSe/ZnS) nano crystal and inclusion complexes of dye molecule with cyclodextrin are presented. Spectral fluorescence of proposed compositions investigated in thin films. Signals from multicolor fluorescence of proposing compositions may be combined to definite spectral codes that could be used for tracking or verification of different objects. Calibration bar of signal within spectral codes guarantee high reliability in practical application of proposed multicolor compositions. Express analysis the size of nanoparticles during their synthesis and purification by spectroscopic methods is suggested. Application of Cyclodextrin molecules as target delivery systems is considered. (authors)

Wnt signaling in limb organogenesis

OpenAIRE

Geetha-Loganathan, Poongodi; Nimmagadda, Suresh; Scaal, Martin

2008-01-01

Secreted signaling molecules of the Wnt family have been found to play a central role in controlling embryonic development of a wide range of taxa from Hydra to humans. The most extensively studied Wnt signaling pathway is the canonical Wnt pathway, which controls gene expression by stabilizing β-catenin, and regulates a multitude of developmental processes. More recently, noncanonical Wnt pathways, which are β-catenin-independent, have been found to be important developmental regulators. Und...

Nanoimprinted distributed feedback dye laser sensor for real-time imaging of small molecule diffusion

DEFF Research Database (Denmark)

Vannahme, Christoph; Dufva, Martin; Kristensen, Anders

2014-01-01

Label-free imaging is a promising tool for the study of biological processes such as cell adhesion and small molecule signaling processes. In order to image in two dimensions of space current solutions require motorized stages which results in low imaging frame rates. Here, a highly sensitive...... distributed feedback (DFB) dye laser sensor for real-time label-free imaging without any moving parts enabling a frame rate of 12 Hz is presented. The presence of molecules on the laser surface results in a wavelength shift which is used as sensor signal. The unique DFB laser structure comprises several areas...

Voltage-Driven Conformational Switching with Distinct Raman Signature in a Single-Molecule Junction.

Science.gov (United States)

Bi, Hai; Palma, Carlos-Andres; Gong, Yuxiang; Hasch, Peter; Elbing, Mark; Mayor, Marcel; Reichert, Joachim; Barth, Johannes V

2018-04-11

Precisely controlling well-defined, stable single-molecule junctions represents a pillar of single-molecule electronics. Early attempts to establish computing with molecular switching arrays were partly challenged by limitations in the direct chemical characterization of metal-molecule-metal junctions. While cryogenic scanning probe studies have advanced the mechanistic understanding of current- and voltage-induced conformational switching, metal-molecule-metal conformations are still largely inferred from indirect evidence. Hence, the development of robust, chemically sensitive techniques is instrumental for advancement in the field. Here we probe the conformation of a two-state molecular switch with vibrational spectroscopy, while simultaneously operating it by means of the applied voltage. Our study emphasizes measurements of single-molecule Raman spectra in a room-temperature stable single-molecule switch presenting a signal modulation of nearly 2 orders of magnitude.

Specificity, cross-talk and adaptation in Interferon signaling

Science.gov (United States)

Zilman, Anton

Innate immune system is the first line of defense of higher organisms against pathogens. It coordinates the behavior of millions of cells of multiple types, achieved through numerous signaling molecules. This talk focuses on the signaling specificity of a major class of signaling molecules - Type I Interferons - which are also used therapeutically in the treatment of a number of diseases, such as Hepatitis C, multiple sclerosis and some cancers. Puzzlingly, different Interferons act through the same cell surface receptor but have different effects on the target cells. They also exhibit a strange pattern of temporal cross-talk resulting in a serious clinical problem - loss of response to Interferon therapy. We combined mathematical modeling with quantitative experiments to develop a quantitative model of specificity and adaptation in the Interferon signaling pathway. The model resolves several outstanding experimental puzzles and directly affects the clinical use of Type I Interferons in treatment of viral hepatitis and other diseases.

Molecule Matters van der Waals Molecules

Indian Academy of Sciences (India)

Home; Journals; Resonance – Journal of Science Education; Volume 14; Issue 12. Molecule Matters van der Waals Molecules - Noble Gas Clusters are London Molecules! E Arunan. Feature Article Volume 14 Issue 12 December 2009 pp 1210-1222 ...

Investigation of photobleaching and saturation of single molecules by fluorophore recrossing events

Energy Technology Data Exchange (ETDEWEB)

Burrows, Sean M.; Reif, Randall D. [Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX 79409-1061 (United States); Pappas, Dimitri [Department of Chemistry and Biochemistry, Texas Tech University, Lubbock, TX 79409-1061 (United States)], E-mail: d.pappas@ttu.edu

2007-08-15

A method for investigation of photobleaching and saturation of single molecules by fluorophore recrossing events in a laser beam is described. The diffraction-limited probe volumes encountered in single-molecule detection (SMD) produce high excitation irradiance, which can decrease available signal. The single molecules of several dyes were detected and the data was used to extract interpeak times above a defined threshold value. The interpeak times revealed the number of fluorophore recrossing events. The number of molecules detected that were within 2 ms of each other represented a molecular recrossing for this work. Calcein, fluorescein and R-phycoerythrin were analyzed and the saturation irradiance and photobleaching effects were determined as a function of irradiance. This approach is simple and it serves as a method of optimizing experimental conditions for single-molecule detection.

RsaM: a transcriptional regulator of Burkholderia spp. with novel fold

Energy Technology Data Exchange (ETDEWEB)

Michalska, Karolina [Midwest Center for Structural Genomics, Argonne National Laboratory, IL USA; Structural Biology Center, Biosciences Division, Argonne National Laboratory, IL USA; Chhor, Gekleng [Midwest Center for Structural Genomics, Argonne National Laboratory, IL USA; Clancy, Shonda [Midwest Center for Structural Genomics, Argonne National Laboratory, IL USA; Jedrzejczak, Robert [Midwest Center for Structural Genomics, Argonne National Laboratory, IL USA; Babnigg, Gyorgy [Midwest Center for Structural Genomics, Argonne National Laboratory, IL USA; Winans, Stephen C. [Department of Microbiology, Cornell University, Ithaca NY USA; Joachimiak, Andrzej [Midwest Center for Structural Genomics, Argonne National Laboratory, IL USA; Structural Biology Center, Biosciences Division, Argonne National Laboratory, IL USA; Department of Biochemistry and Molecular Biology, University of Chicago, IL USA

2014-07-04

Burkholderia cepacia complex (Bcc) is a set of closely related bacterial species that are notorious pathogens of cystic fibrosis patients, responsible for life-threatening lung infections. Expression of several virulence factors of Bcc is controlled by a mechanism known as quorum sensing (QS). QS is a means of bacterial communication used to coordinate gene expression in a cell-density-dependent manner. The system involves the production of diffusible signaling molecules (N-acyl-L-homoserine lactones, AHLs), that bind to cognate transcriptional regulators and influence their ability to regulate gene expression. One such system that is highly conserved in Bcc consists of CepI and CepR. CepI is AHL synthase, while CepR is an AHL-dependent transcription factor. In most members of the Bcc group, the cepI and cepR genes are divergently transcribed and separated by additional genes. One of them, bcam1869, encodes the BcRsaM protein, which was recently postulated to modulate the abundance or activity of CepI or CepR. Here we show the crystal structure of BcRsaM from B. cenocepacia J2315. It is a single-domain protein with unique topology and presents a novel fold. The protein is a dimer in the crystal and in solution. This regulator has no known DNA binding motifs and direct binding of BcRsaM to the cepI promoter could not be detected in in vitro assays. Therefore, we propose that the modulatory action of RsaM might result from interactions with other components of the QS machinery rather than from direct association with the DNA promoter.

Blu-ray based optomagnetic aptasensor for detection of small molecules

DEFF Research Database (Denmark)

Yang, Jaeyoung; Donolato, Marco; Pinto, Alessandro

2016-01-01

This paper describes an aptamer-based optomagnetic biosensor for detection of a small molecule based on target binding-induced inhibition of magnetic nanoparticle (MNP) clustering. For the detection of a target small molecule, two mutually exclusive binding reactions (aptamer-target binding...... the hydrodynamic size distribution of MNPs and their clusters. A commercial Blu-ray optical pickup unit is used for optical signal acquisition, which enables the establishment of a low-cost and miniaturized biosensing platform. Experimental results show that the degree of MNP clustering correlates well...

The Signaling Pathways Involved in Chondrocyte Differentiation and Hypertrophic Differentiation

Directory of Open Access Journals (Sweden)

Jianmei Li

2016-01-01

Full Text Available Chondrocytes communicate with each other mainly via diffusible signals rather than direct cell-to-cell contact. The chondrogenic differentiation of mesenchymal stem cells (MSCs is well regulated by the interactions of varieties of growth factors, cytokines, and signaling molecules. A number of critical signaling molecules have been identified to regulate the differentiation of chondrocyte from mesenchymal progenitor cells to their terminal maturation of hypertrophic chondrocytes, including bone morphogenetic proteins (BMPs, SRY-related high-mobility group-box gene 9 (Sox9, parathyroid hormone-related peptide (PTHrP, Indian hedgehog (Ihh, fibroblast growth factor receptor 3 (FGFR3, and β-catenin. Except for these molecules, other factors such as adenosine, O2 tension, and reactive oxygen species (ROS also have a vital role in cartilage formation and chondrocyte maturation. Here, we outlined the complex transcriptional network and the function of key factors in this network that determine and regulate the genetic program of chondrogenesis and chondrocyte differentiation.

Superradiance Effects in the Linear and Nonlinear Optical Response of Quantum Dot Molecules

Science.gov (United States)

Sitek, A.; Machnikowski, P.

2008-11-01

We calculate the linear optical response from a single quantum dot molecule and the nonlinear, four-wave-mixing response from an inhomogeneously broadened ensemble of such molecules. We show that both optical signals are affected by the coupling-dependent superradiance effect and by optical interference between the two polarizations. As a result, the linear and nonlinear responses are not identical.

Diethyl hexyl phthalate-induced changes in insulin signaling molecules and the protective role of antioxidant vitamins in gastrocnemius muscle of adult male rat

International Nuclear Information System (INIS)

Srinivasan, Chinnapaiyan; Khan, Adam Ismail; Balaji, Venkataraman; Selvaraj, Jayaraman; Balasubramanian, Karundevi

2011-01-01

Diethyl hexyl phthalate (DEHP) is an endocrine disruptor, it influences various organ systems in human beings and experimental animals. DEHP reduced the serum testosterone and increased the blood glucose, estradiol, T 3 and T 4 in rats. However, the effect of DEHP on insulin signaling and glucose oxidation in skeletal muscle is not known. Adult male albino rats were divided into four groups: Group I: Control; Groups II and III: DEHP treated (dissolved in olive oil at a dose of 10 and 100 mg/kg body weight, respectively, once daily through gastric intubation for 30 days); and Group IV: DEHP (100 mg/kg body weight) plus vitamins E (50 mg/kg body weight) and C (100 mg/kg body weight) dissolved in olive oil and distilled water, respectively, once daily through gastric intubation for 30 days. On completion of treatment, animals were euthanized and perfused (whole body); gastrocnemius muscle was dissected out and subjected to assessment of various parameters. DEHP treatment increased the H 2 O 2 , hydroxyl radical levels and lipid peroxidation which disrupt the membrane integrity and insulin receptor. DEHP impaired the insulin signal transduction, glucose uptake and oxidation through decreased expression of plasma membrane GLUT4, which may partly be responsible for the elevation of fasting blood glucose level. The present study suggests that DEHP exposure affects glucose oxidation in skeletal muscle and is mediated through enhanced lipid peroxidation, impaired insulin signaling and GLUT4 expression in plasma membrane. Antioxidant vitamins (C and E) have a protective role against the adverse effect of DEHP. -- Highlights: ► DEHP treatment significantly decreased serum insulin and testosterone levels. ► Increased ROS and decreased glucose uptake were observed in DEHP treated animals. ► Impaired insulin signaling in gastrocnemius muscle was observed in DEHP treatment. ► Vitamins C and E alter ROS, glucose uptake, oxidation and insulin signaling molecules.

Quorum Quenching in Culturable Phyllosphere Bacteria from Tobacco

Directory of Open Access Journals (Sweden)

Guoqiang Zhuang

2013-07-01

Full Text Available Many Gram-negative plant pathogenic bacteria employ a N-acylhomoserine lactone (AHL-based quorum sensing (QS system to regulate their virulence traits. A sustainable biocontrol strategy has been developed using quorum quenching (QQ bacteria to interfere with QS and protect plants from pathogens. Here, the prevalence and the diversity of QQ strains inhabiting tobacco leaf surfaces were explored. A total of 1177 leaf-associated isolates were screened for their ability to disrupt AHL-mediated QS, using the biosensor Chromobacterium violaceum CV026. One hundred and sixty-eight strains (14% are capable of interfering with AHL activity. Among these, 106 strains (63% of the culturable quenchers can enzymatically degrade AHL molecules, while the remaining strains might use other QS inhibitors to interrupt the chemical communication. Moreover, almost 79% of the QQ strains capable of inactivating AHLs enzymatically have lactonase activity. Further phylogenetic analysis based on 16S rDNA revealed that the leaf-associated QQ bacteria can be classified as Bacillus sp., Acinetobacter sp., Lysinibacillus sp., Serratia sp., Pseudomonas sp., and Myroides sp. The naturally occurring diversity of bacterial quenchers might provide opportunities to use them as effective biocontrol reagents for suppressing plant pathogen in situ.

Flavonoids from Piper delineatum modulate quorum-sensing-regulated phenotypes in Vibrio harveyi.

Science.gov (United States)

Martín-Rodríguez, Alberto J; Ticona, Juan C; Jiménez, Ignacio A; Flores, Ninoska; Fernández, José J; Bazzocchi, Isabel L

2015-09-01

Quorum sensing (QS), or bacterial cell-to-cell communication, is a key process for bacterial colonization of substrata through biofilm formation, infections, and production of virulence factors. In an ongoing investigation of bioactive secondary metabolites from Piper species, four new flavonoids (1-4), along with five known ones (5-9) were isolated from the leaves of Piper delineatum. Their stereostructures were established by spectroscopic and spectrometric methods, including 1D and 2D NMR experiments, and comparison with data reported in the literature. The compounds were screened for their ability to interfere with QS signaling in the bacterial model Vibrio harveyi. Four compounds from this series (2, 3, 6, and 7) exhibited remarkable activity in the micromolar range, being compounds 3 and 7 particularly attractive since they did not affect bacterial growth. The results suggest that these flavonoids disrupt QS-mediated bioluminescence by interaction with elements downstream LuxO in the QS circuit of V. harveyi, and also, they exhibited a strong dose-dependent inhibition of biofilm formation. The present findings shed light on the QS inhibition mechanisms of flavonoids, underlining their potential applications. Copyright © 2015 Elsevier Ltd. All rights reserved.

Enhancement of Chiroptical Signals by Circular Differential Mie Scattering of Nanoparticles

OpenAIRE

SeokJae Yoo; Q-Han Park

2015-01-01

We enhance the weak optical signals of small chiral molecules via circular differential Mie scattering (CDMS) of nanoparticles immersed in them. CDMS is the preferential Mie scattering of left- and right-handed circularly polarized light by nanoparticles whose sizes are about the same as the wavelength of light. Solving the Mie scattering theory for chiral media, we find that the CDMS signal of the particle is linearly proportional to the chirality parameter κ of the molecules. This linear am...

Seismic Attenuation Tomography of the Rupture Zone of the 2010 Maule, Chile, Earthquake

Science.gov (United States)

Torpey, M. E.; Russo, R. M.; Panning, M. P.

2014-12-01

We used measurements of differential S to P seismic attenuation in the rupture zone of the 2010 Mw 8.8 Maule, Chile earthquake (33°S-38°S) to characterize the seismic attenuation structure of the South American crust and upper mantle wedge. We used data obtained from the IRIS CHAMP rapid-response temporary seismic network, filtered between 0.7-20 Hz. For events with large signal to noise ratios, we visually identified the P and S arrivals on the seismograms and used an evolving time window to determine 400 individual Qs and t* values and their uncertainties using a spectral ratio method. Using a phase pair method allows us to neglect the source-time function and instrument response of each P-S phase pair. Assuming a constant Qp/Qs ratio for a given P-S phase pair, we evaluated the 400 spectral ratios and discarded portions of the evolving time window that incorporate multipathed phases. We recalculated the Qs and standard deviation of the retained window and excluded measurements with standard deviations larger than half of the Qs value. We also excluded measurements that span frequency windows longer than 10 Hz as they contain noise that contaminates Qs measurements. We examined ~200 local events yielding a total of 1,076 path-integrated Q­s measurements. Qs values are low (100-400) for the majority of ray paths evaluated, however we observe a spatial distribution of low path-integrated Qs values (100-300) in the northeastern portion of the rupture zone and higher values (300-600) in the southwest. We divided the rupture zone into cubes and implemented a bounded linear inequality least squares inversion (0<Qs<1200) to solve for Qs in individual model regions. We used a constant starting model of Qs=450 and solved for perturbations to the model using our observed δt* values and a radial-earth velocity model (IASPI91). Our ray coverage provides good resolution extending to depths of ~75 km in the mantle wedge.

Differential effects of Th1, monocyte/macrophage and Th2 cytokine mixtures on early gene expression for molecules associated with metabolism, signaling and regulation in central nervous system mixed glial cell cultures

Directory of Open Access Journals (Sweden)

Studzinski Diane

2009-01-01

Full Text Available Abstract Background Cytokines secreted by immune cells and activated glia play central roles in both the pathogenesis of and protection from damage to the central nervous system (CNS in multiple sclerosis (MS. Methods We have used gene array analysis to identify the initial direct effects of cytokines on CNS glia by comparing changes in early gene expression in CNS glial cultures treated for 6 hours with cytokines typical of those secreted by Th1 and Th2 lymphocytes and monocyte/macrophages (M/M. Results In two previous papers, we summarized effects of these cytokines on immune-related molecules, and on neural and glial related proteins, including neurotrophins, growth factors and structural proteins. In this paper, we present the effects of the cytokines on molecules involved in metabolism, signaling and regulatory mechanisms in CNS glia. Many of the changes in gene expression were similar to those seen in ischemic preconditioning and in early inflammatory lesions in experimental autoimmune encephalomyelitis (EAE, related to ion homeostasis, mitochondrial function, neurotransmission, vitamin D metabolism and a variety of transcription factors and signaling pathways. Among the most prominent changes, all three cytokine mixtures markedly downregulated the dopamine D3 receptor, while Th1 and Th2 cytokines downregulated neuropeptide Y receptor 5. An unexpected finding was the large number of changes related to lipid metabolism, including several suggesting a switch from diacylglycerol to phosphatidyl inositol mediated signaling pathways. Using QRT-PCR we validated the results for regulation of genes for iNOS, arginase and P glycoprotein/multi-drug resistance protein 1 (MDR1 seen at 6 hours with microarray. Conclusion Each of the three cytokine mixtures differentially regulated gene expression related to metabolism and signaling that may play roles in the pathogenesis of MS, most notably with regard to mitochondrial function and neurotransmitter

Lactate in the brain: from metabolic end-product to signalling molecule

KAUST Repository

Magistretti, Pierre J.

2018-03-08

Lactate in the brain has long been associated with ischaemia; however, more recent evidence shows that it can be found there under physiological conditions. In the brain, lactate is formed predominantly in astrocytes from glucose or glycogen in response to neuronal activity signals. Thus, neurons and astrocytes show tight metabolic coupling. Lactate is transferred from astrocytes to neurons to match the neuronal energetic needs, and to provide signals that modulate neuronal functions, including excitability, plasticity and memory consolidation. In addition, lactate affects several homeostatic functions. Overall, lactate ensures adequate energy supply, modulates neuronal excitability levels and regulates adaptive functions in order to set the \\'homeostatic tone\\' of the nervous system.

Detection of tmRNA molecules on microarrays at low temperatures using helper oligonucleotides

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Palta Priit

2010-04-01

Full Text Available Abstract Background The hybridization of synthetic Streptococcus pneumoniae tmRNA on a detection microarray is slow at 34°C resulting in low signal intensities. Results We demonstrate that adding specific DNA helper oligonucleotides (chaperones to the hybridization buffer increases the signal strength at a given temperature and thus makes the specific detection of Streptococcus pneumoniae tmRNA more sensitive. No loss of specificity was observed at low temperatures compared to hybridization at 46°C. The effect of the chaperones can be explained by disruption of the strong secondary and tertiary structure of the target RNA by the selective hybridization of helper molecules. The amplification of the hybridization signal strength by chaperones is not necessarily local; we observed increased signal intensities in both local and distant regions of the target molecule. Conclusions The sensitivity of the detection of tmRNA at low temperature can be increased by chaperone oligonucleotides. Due to the complexity of RNA secondary and tertiary structures the effect of any individual chaperone is currently not predictable.

Molecule Matters van der Waals Molecules

Indian Academy of Sciences (India)

Home; Journals; Resonance – Journal of Science Education; Volume 15; Issue 7. Molecule Matters van der Waals Molecules - Rg•••HF Complexes are Debye Molecules! E Arunan. Feature Article Volume 15 Issue 7 July 2010 pp 667-674. Fulltext. Click here to view fulltext PDF. Permanent link:

The neural cell adhesion molecule

DEFF Research Database (Denmark)

Berezin, V; Bock, E; Poulsen, F M

2000-01-01

During the past year, the understanding of the structure and function of neural cell adhesion has advanced considerably. The three-dimensional structures of several of the individual modules of the neural cell adhesion molecule (NCAM) have been determined, as well as the structure of the complex...... between two identical fragments of the NCAM. Also during the past year, a link between homophilic cell adhesion and several signal transduction pathways has been proposed, connecting the event of cell surface adhesion to cellular responses such as neurite outgrowth. Finally, the stimulation of neurite...

Probing Intranuclear Environments at the Single-Molecule Level

Science.gov (United States)

Grünwald, David; Martin, Robert M.; Buschmann, Volker; Bazett-Jones, David P.; Leonhardt, Heinrich; Kubitscheck, Ulrich; Cardoso, M. Cristina

2008-01-01

Genome activity and nuclear metabolism clearly depend on accessibility, but it is not known whether and to what extent nuclear structures limit the mobility and access of individual molecules. We used fluorescently labeled streptavidin with a nuclear localization signal as an average-sized, inert protein to probe the nuclear environment. The protein was injected into the cytoplasm of mouse cells, and single molecules were tracked in the nucleus with high-speed fluorescence microscopy. We analyzed and compared the mobility of single streptavidin molecules in structurally and functionally distinct nuclear compartments of living cells. Our results indicated that all nuclear subcompartments were easily and similarly accessible for such an average-sized protein, and even condensed heterochromatin neither excluded single molecules nor impeded their passage. The only significant difference was a higher frequency of transient trappings in heterochromatin, which lasted only tens of milliseconds. The streptavidin molecules, however, did not accumulate in heterochromatin, suggesting comparatively less free volume. Interestingly, the nucleolus seemed to exclude streptavidin, as it did many other nuclear proteins, when visualized by conventional fluorescence microscopy. The tracking of single molecules, nonetheless, showed no evidence for repulsion at the border but relatively unimpeded passage through the nucleolus. These results clearly show that single-molecule tracking can provide novel insights into mobility of proteins in the nucleus that cannot be obtained by conventional fluorescence microscopy. Our results suggest that nuclear processes may not be regulated at the level of physical accessibility but rather by local concentration of reactants and availability of binding sites. PMID:18065482

Carbon Nanotube Biosensors for Space Molecule Detection and Clinical Molecular Diagnostics

Science.gov (United States)

Han, Jie

2001-01-01

Both space molecule detection and clinical molecule diagnostics need to develop ultra sensitive biosensors for detection of less than attomole molecules such as amino acids for DNA. However all the electrode sensor systems including those fabricated from the existing carbon nanotubes, have a background level of nA (nanoAmp). This has limited DNA or other molecule detection to nA level or molecules whose concentration is, much higher than attomole level. A program has been created by NASA and NCI (National Cancer Institute) to exploit the possibility of carbon nanotube based biosensors to solve this problem for both's interest. In this talk, I will present our effort on the evaluation and novel design of carbon nanotubes as electrode biosensors with strategies to minimize background currents while maximizing signal intensity.The fabrication of nanotube electrode arrays, immobilization of molecular probes on nanotube electrodes and in vitro biosensor testing will also be discussed.

Calcium and Nuclear Signaling in Prostate Cancer

OpenAIRE

Ivan V. Maly; Wilma A. Hofmann

2018-01-01

Recently, there have been a number of developments in the fields of calcium and nuclear signaling that point to new avenues for a more effective diagnosis and treatment of prostate cancer. An example is the discovery of new classes of molecules involved in calcium-regulated nuclear import and nuclear calcium signaling, from the G protein-coupled receptor (GPCR) and myosin families. This review surveys the new state of the calcium and nuclear signaling fields with the aim of identifying the un...

Cholinergic signalling in gut immunity

NARCIS (Netherlands)

Dhawan, Shobhit; Cailotto, Cathy; Harthoorn, Lucien F.; de Jonge, Wouter J.

2012-01-01

The gut immune system shares many signalling molecules and receptors with the autonomic nervous system. A good example is the vagal neurotransmitter acetylcholine (ACh), for which many immune cell types express cholinergic receptors (AChR). In the last decade the vagal nerve has emerged as an

Single-Molecule Chemistry with Surface- and Tip-Enhanced Raman Spectroscopy.

Science.gov (United States)

Zrimsek, Alyssa B; Chiang, Naihao; Mattei, Michael; Zaleski, Stephanie; McAnally, Michael O; Chapman, Craig T; Henry, Anne-Isabelle; Schatz, George C; Van Duyne, Richard P

2017-06-14

Single-molecule (SM) surface-enhanced Raman spectroscopy (SERS) and tip-enhanced Raman spectroscopy (TERS) have emerged as analytical techniques for characterizing molecular systems in nanoscale environments. SERS and TERS use plasmonically enhanced Raman scattering to characterize the chemical information on single molecules. Additionally, TERS can image single molecules with subnanometer spatial resolution. In this review, we cover the development and history of SERS and TERS, including the concept of SERS hot spots and the plasmonic nanostructures necessary for SM detection, the past and current methodologies for verifying SMSERS, and investigations into understanding the signal heterogeneities observed with SMSERS. Moving on to TERS, we cover tip fabrication and the physical origins of the subnanometer spatial resolution. Then, we highlight recent advances of SMSERS and TERS in fields such as electrochemistry, catalysis, and SM electronics, which all benefit from the vibrational characterization of single molecules. SMSERS and TERS provide new insights on molecular behavior that would otherwise be obscured in an ensemble-averaged measurement.

Mitogen activated protein kinase signaling in the kidney: Target for intervention?

NARCIS (Netherlands)

de Borst, M.H.; Wassef, L.; Kelly, D.J.; van Goor, H.; Navis, Ger Jan

2006-01-01

Mitogen activated protein kinases (MAPKs) are intracellular signal transduction molecules, which connect cell-surface receptor signals to intracellular processes. MAPKs regulate a range of cellular activities including cell proliferation, gene expression, apoptosis, cell differentiation and cytokine

Selection of the N-acylhomoserine lactone-degrading bacterium Alteromonas stellipolaris PQQ-42 and of its potential for biocontrol in aquaculture

Directory of Open Access Journals (Sweden)

Marta eTorres

2016-05-01

Full Text Available The production of virulence factors by many pathogenic microorganisms depends on the intercellular communication system called quorum sensing (QS, which involves the production and release of signal molecules known as autoinducers. Based on this, new-therapeutic strategies have emerged for the treatment of a variety of infections, such as the enzymatic degradation of signalling molecules, known as quorum quenching (QQ. In this study, we present the screening of QQ activity amongst 450 strains isolated from a bivalve hatchery in Granada (Spain, and the selection of the strain PQQ-42, which degrades a wide range of N-acylhomoserine lactones (AHLs. The selected strain, identified as Alteromonas stellipolaris, degraded the accumulation of AHLs and reduced the production of protease and chitinase and swimming motility of a Vibrio species in co-cultivation experiments in vitro. In the bio-control experiment, strain PQQ-42 significantly reduced the pathogenicity of V. mediterranei VibC-Oc-097 upon the coral Oculina patagonica showing a lower degree of tissue damage (29.25±14.63 % in its presence, compared to when the coral was infected with V. mediterranei VibC-Oc-097 alone (77.53±13.22 %. Our results suggest that this AHL-degrading bacterium may have biotechnological applications in aquaculture.

Radiation-induced perturbation of cell-to-cell signalling and communication

International Nuclear Information System (INIS)

Mariotti, L.; Facoetti, A.; Bertolotti, A.; Ranza, E.; Alloni, D.; Ottolenghi, A.

2011-01-01

The investigation of the bystander phenomena (i.e. the induction of damage in cells not directly traversed by radiation) is strictly related to the study of the mechanisms of intercellular communication and of the perturbative effects of radiation. A new possible way to try to solve the bystander puzzle is through a 'systems radiation biology' approach with the total integration of experimental and theoretical activities. In particular, this contribution will focus on: (1) 'ad hoc' experiments designed to quantify key parameters involved in intercellular signalling (focusing, as a pilot study, on release, decay and internalization of interleukin-6 molecules, their modulation by radiation, and possible differences between in vivo/in vitro behaviour); (2) the implementation and the development of two different modelling approaches: a stochastic model (based on a Monte Carlo code) that takes account of the local mechanisms of release and internalization of signalling molecules (e.g. cytokines) and an analytical model where signal molecules are treated as a population and their temporal behaviour is described by differential equations. This approach provided instruments to investigate the complex phenomena of signal transmission and the role of cell communication to guarantee (maintain) the robustness of the in vitro experimental systems against the effects of perturbations. (authors)

A role for adhesion molecules in contact-dependent T help for B cells

DEFF Research Database (Denmark)

Owens, T

1991-01-01

The role of cell contact in T-dependent B cell activation was examined. Small resting B cells from C57BL/6 mice were cultured with CBA-derived, non-alloreactive cloned T helper cells in anti-T cell receptor V beta 8-coated microwells. This induced polyclonal B cell activation to enter cell cycle...... that continued cell contact involving adhesion/accessory molecules induces B cells to proliferate and to respond to T cell lymphokines. A signaling role for cell interaction molecules on B cells is proposed, similar to the role of these and analogous molecules on T cells....

TGFb signalling inhibits DLK1 expression during chondrogenesis in vitro

DEFF Research Database (Denmark)

Harkness, Linda; Taipaleenmaki, Hanna; Saamanen, Anna-Marja

2011-01-01

the effect of a number of signalling molecules on DLK1 expression during in vitro chondrogenic differentiation in mouse embryonic limb bud mesenchymal micromass cultures and mouse embryonic fibroblast (MEF) pellet cultures. Dlk1 was initially expressed during mesenchymal condensation and chondrocyte...... proliferation, in parallel with expression of Sox9 and Col2a1, and was down-regulated upon expression of Col10a1 by hypertrophic chondrocytes. Among a number of molecules that affected chondrogenesis, TGF-b signalling regulated Dlk1expression. TGF-b1-induced chondrogenesis was associated with decreased Dlk1...... expression and these effects were abolished by the TGF-b signalling inhibitor SB4311542 suggesting an involvement of DLK1/FA1 in mediating the function of TGF-b1 signalling in chondrogenesis. In support of this hypothesis, we found that TGF-b1 enhanced chondrocyte differentiation in dlk1-/- MEF compared...

Magnetic field modification of ultracold molecule-molecule collisions

International Nuclear Information System (INIS)

Tscherbul, T V; Suleimanov, Yu V; Aquilanti, V; Krems, R V

2009-01-01

We present an accurate quantum mechanical study of molecule-molecule collisions in the presence of a magnetic field. The work focuses on the analysis of elastic scattering and spin relaxation in collisions of O 2 ( 3 Σ g - ) molecules at cold (∼0.1 K) and ultracold (∼10 -6 K) temperatures. Our calculations show that magnetic spin relaxation in molecule-molecule collisions is extremely efficient except at magnetic fields below 1 mT. The rate constant for spin relaxation at T=0.1 K and a magnetic field of 0.1 T is found to be as large as 6.1x10 -11 cm -3 s -1 . The magnetic field dependence of elastic and inelastic scattering cross sections at ultracold temperatures is dominated by a manifold of Feshbach resonances with the density of ∼100 resonances per Tesla for collisions of molecules in the absolute ground state. This suggests that the scattering length of ultracold molecules in the absolute ground state can be effectively tuned in a very wide range of magnetic fields. Our calculations demonstrate that the number and properties of the magnetic Feshbach resonances are dramatically different for molecules in the absolute ground and excited spin states. The density of Feshbach resonances for molecule-molecule scattering in the low-field-seeking Zeeman state is reduced by a factor of 10.

Fluorescent labeling of NASBA amplified tmRNA molecules for microarray applications

Directory of Open Access Journals (Sweden)

Kaplinski Lauris

2009-05-01

Full Text Available Abstract Background Here we present a novel promising microbial diagnostic method that combines the sensitivity of Nucleic Acid Sequence Based Amplification (NASBA with the high information content of microarray technology for the detection of bacterial tmRNA molecules. The NASBA protocol was modified to include aminoallyl-UTP (aaUTP molecules that were incorporated into nascent RNA during the NASBA reaction. Post-amplification labeling with fluorescent dye was carried out subsequently and tmRNA hybridization signal intensities were measured using microarray technology. Significant optimization of the labeled NASBA protocol was required to maintain the required sensitivity of the reactions. Results Two different aaUTP salts were evaluated and optimum final concentrations were identified for both. The final 2 mM concentration of aaUTP Li-salt in NASBA reaction resulted in highest microarray signals overall, being twice as high as the strongest signals with 1 mM aaUTP Na-salt. Conclusion We have successfully demonstrated efficient combination of NASBA amplification technology with microarray based hybridization detection. The method is applicative for many different areas of microbial diagnostics including environmental monitoring, bio threat detection, industrial process monitoring and clinical microbiology.

Signaling flux redistribution at toll-like receptor pathway junctions.

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Kumar Selvarajoo

Full Text Available Various receptors on cell surface recognize specific extracellular molecules and trigger signal transduction altering gene expression in the nucleus. Gain or loss-of-function mutations of one molecule have shown to affect alternative signaling pathways with a poorly understood mechanism. In Toll-like receptor (TLR 4 signaling, which branches into MyD88- and TRAM-dependent pathways upon lipopolysaccharide (LPS stimulation, we investigated the gain or loss-of-function mutations of MyD88. We predict, using a computational model built on the perturbation-response approach and the law of mass conservation, that removal and addition of MyD88 in TLR4 activation, enhances and impairs, respectively, the alternative TRAM-dependent pathway through signaling flux redistribution (SFR at pathway branches. To verify SFR, we treated MyD88-deficient macrophages with LPS and observed enhancement of TRAM-dependent pathway based on increased IRF3 phosphorylation and induction of Cxcl10 and Ifit2. Furthermore, increasing the amount of MyD88 in cultured cells showed decreased TRAM binding to TLR4. Investigating another TLR4 pathway junction, from TRIF to TRAF6, RIP1 and TBK1, the removal of MyD88-dependent TRAF6 increased expression of TRAM-dependent Cxcl10 and Ifit2. Thus, we demonstrate that SFR is a novel mechanism for enhanced activation of alternative pathways when molecules at pathway junctions are removed. Our data suggest that SFR may enlighten hitherto unexplainable intracellular signaling alterations in genetic diseases where gain or loss-of-function mutations are observed.

Diethyl hexyl phthalate-induced changes in insulin signaling molecules and the protective role of antioxidant vitamins in gastrocnemius muscle of adult male rat

Energy Technology Data Exchange (ETDEWEB)

Srinivasan, Chinnapaiyan; Khan, Adam Ismail; Balaji, Venkataraman; Selvaraj, Jayaraman; Balasubramanian, Karundevi, E-mail: kbala82@rediffmail.com

2011-12-15

-Right-Pointing-Pointer Vitamins C and E alter ROS, glucose uptake, oxidation and insulin signaling molecules.

Analysis of activin/TGFB-signaling modulators within the normal and dysfunctional adult human testis reveals evidence of altered signaling capacity in a subset of seminomas

DEFF Research Database (Denmark)

Dias, Vinali L; Rajpert-De Meyts, Ewa; McLachlan, Robert

2009-01-01

Activin is a pleiotropic growth factor belonging to the transforming growth factor-beta (TGFB) superfamily of signaling molecules. Regulated activin signaling is known to influence several steps in rodent male gamete differentiation. TGFB ligand isoforms, TGFB1-B3, also influence germ cell surviv...

A general approach to break the concentration barrier in single-molecule imaging

KAUST Repository

Loveland, Anna B.

2012-09-09

Single-molecule fluorescence imaging is often incompatible with physiological protein concentrations, as fluorescence background overwhelms an individual molecule\\'s signal. We solve this problem with a new imaging approach called PhADE (PhotoActivation, Diffusion and Excitation). A protein of interest is fused to a photoactivatable protein (mKikGR) and introduced to its surface-immobilized substrate. After photoactivation of mKikGR near the surface, rapid diffusion of the unbound mKikGR fusion out of the detection volume eliminates background fluorescence, whereupon the bound molecules are imaged. We labeled the eukaryotic DNA replication protein flap endonuclease 1 with mKikGR and added it to replication-competent Xenopus laevis egg extracts. PhADE imaging of high concentrations of the fusion construct revealed its dynamics and micrometer-scale movements on individual, replicating DNA molecules. Because PhADE imaging is in principle compatible with any photoactivatable fluorophore, it should have broad applicability in revealing single-molecule dynamics and stoichiometry of macromolecular protein complexes at previously inaccessible fluorophore concentrations. © 2012 Nature America, Inc. All rights reserved.

Quorum-sensing regulation of the biofilm matrix genes (pel) of Pseudomonas aeruginosa.

Science.gov (United States)

Sakuragi, Yumiko; Kolter, Roberto

2007-07-01

Quorum sensing (QS) has been previously shown to play an important role in the development of Pseudomonas aeruginosa biofilms (D. G. Davies et al., Science 280:295-298, 1998). Although QS regulation of swarming and DNA release has been shown to play important roles in biofilm development, regulation of genes directly involved in biosynthesis of biofilm matrix has not been described. Here, transcription of the pel operon, essential for the production of a glucose-rich matrix exopolysaccharide, is shown to be greatly reduced in lasI and rhlI mutants. Chemical complementation of the lasI mutant with 3-oxo-dodecanoyl homoserine lactone restores pel transcription to the wild-type level and biofilm formation ability. These findings thus connect QS signaling and transcription of genes responsible for biofilm matrix biosynthesis.

Detecting high-density ultracold molecules using atom–molecule collision

International Nuclear Information System (INIS)

Chen, Jun-Ren; Kao, Cheng-Yang; Chen, Hung-Bin; Liu, Yi-Wei

2013-01-01

Utilizing single-photon photoassociation, we have achieved ultracold rubidium molecules with a high number density that provides a new efficient approach toward molecular quantum degeneracy. A new detection mechanism for ultracold molecules utilizing inelastic atom–molecule collision is demonstrated. The resonant coupling effect on the formation of the X 1 Σ + g ground state 85 Rb 2 allows for a sufficient number of more deeply bound ultracold molecules, which induced an additional trap loss and heating of the co-existing atoms owing to the inelastic atom–molecule collision. Therefore, after the photoassociation process, the ultracold molecules can be investigated using the absorption image of the ultracold rubidium atoms mixed with the molecules in a crossed optical dipole trap. The existence of the ultracold molecules was then verified, and the amount of accumulated molecules was measured. This method detects the final produced ultracold molecules, and hence is distinct from the conventional trap loss experiment, which is used to study the association resonance. It is composed of measurements of the time evolution of an atomic cloud and a decay model, by which the number density of the ultracold 85 Rb 2 molecules in the optical trap was estimated to be >5.2 × 10 11 cm −3 . (paper)

Scaffold of Selenium Nanovectors and Honey Phytochemicals for Inhibition of Pseudomonas aeruginosa Quorum Sensing and Biofilm Formation

Directory of Open Access Journals (Sweden)

Prateeksha

2017-03-01

Full Text Available Honey is an excellent source of polyphenolic compounds that are effective in attenuating quorum sensing (QS, a chemical process of cell-to-cell communication system used by the opportunistic pathogen Pseudomonas aeruginosa to regulate virulence and biofilm formation. However, lower water solubility and inadequate bioavailability remains major concerns of these therapeutic polyphenols. Its therapeutic index can be improved by using nano-carrier systems to target QS signaling potently. In the present study, we fabricated a unique drug delivery system comprising selenium nanoparticles (SeNPs; non-viral vectors and polyphenols of honey (HP for enhancement of anti-QS activity of HP against P. aeruginosa PAO1. The developed selenium nano-scaffold showed superior anti-QS activity, anti-biofilm efficacy, and anti-virulence potential in both in-vitro and in-vivo over its individual components, SeNPs and HP. LasR is inhibited by selenium nano-scaffold in-vitro. Using computational molecular docking studies, we have also demonstrated that the anti-virulence activity of selenium nano-scaffold is reliant on molecular binding that occurs between HP and the QS receptor LasR through hydrogen bonding and hydrophobic interactions. Our preliminary investigations with selenium-based nano-carriers hold significant promise to improve anti-virulence effectiveness of phytochemicals by enhancing effective intracellular delivery.

The role of neuroimmune signaling in alcoholism.

Science.gov (United States)

Crews, Fulton T; Lawrimore, Colleen J; Walter, T Jordan; Coleman, Leon G

2017-08-01

Alcohol consumption and stress increase brain levels of known innate immune signaling molecules. Microglia, the innate immune cells of the brain, and neurons respond to alcohol, signaling through Toll-like receptors (TLRs), high-mobility group box 1 (HMGB1), miRNAs, pro-inflammatory cytokines and their associated receptors involved in signaling between microglia, other glia and neurons. Repeated cycles of alcohol and stress cause a progressive, persistent induction of HMGB1, miRNA and TLR receptors in brain that appear to underlie the progressive and persistent loss of behavioral control, increased impulsivity and anxiety, as well as craving, coupled with increasing ventral striatal responses that promote reward seeking behavior and increase risk of developing alcohol use disorders. Studies employing anti-oxidant, anti-inflammatory, anti-depressant, and innate immune antagonists further link innate immune gene expression to addiction-like behaviors. Innate immune molecules are novel targets for addiction and affective disorders therapies. This article is part of the Special Issue entitled "Alcoholism". Copyright © 2017 Elsevier Ltd. All rights reserved.

The Organization of the Quorum Sensing luxI/R Family Genes in Burkholderia

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Sándor Pongor

2013-07-01

Full Text Available Members of the Burkholderia genus of Proteobacteria are capable of living freely in the environment and can also colonize human, animal and plant hosts. Certain members are considered to be clinically important from both medical and veterinary perspectives and furthermore may be important modulators of the rhizosphere. Quorum sensing via N-acyl homoserine lactone signals (AHL QS is present in almost all Burkholderia species and is thought to play important roles in lifestyle changes such as colonization and niche invasion. Here we present a census of AHL QS genes retrieved from public databases and indicate that the local arrangement (topology of QS genes, their location within chromosomes and their gene neighborhoods show characteristic patterns that differ between the known Burkholderia clades. In sequence phylogenies, AHL QS genes seem to cluster according to the local gene topology rather than according to the species, which suggests that the basic topology types were present prior to the appearance of current Burkholderia species. The data are available at http://net.icgeb.org/burkholderia/.

The Organization of the Quorum Sensing luxI/R Family Genes in Burkholderia

Science.gov (United States)

Choudhary, Kumari Sonal; Hudaiberdiev, Sanjarbek; Gelencsér, Zsolt; Coutinho, Bruna Gonçalves; Venturi, Vittorio; Pongor, Sándor

2013-01-01

Members of the Burkholderia genus of Proteobacteria are capable of living freely in the environment and can also colonize human, animal and plant hosts. Certain members are considered to be clinically important from both medical and veterinary perspectives and furthermore may be important modulators of the rhizosphere. Quorum sensing via N-acyl homoserine lactone signals (AHL QS) is present in almost all Burkholderia species and is thought to play important roles in lifestyle changes such as colonization and niche invasion. Here we present a census of AHL QS genes retrieved from public databases and indicate that the local arrangement (topology) of QS genes, their location within chromosomes and their gene neighborhoods show characteristic patterns that differ between the known Burkholderia clades. In sequence phylogenies, AHL QS genes seem to cluster according to the local gene topology rather than according to the species, which suggests that the basic topology types were present prior to the appearance of current Burkholderia species. The data are available at http://net.icgeb.org/burkholderia/. PMID:23820583

Surface-enhanced resonance Raman scattering spectroscopy of single R6G molecules

Institute of Scientific and Technical Information of China (English)

Zhou Zeng-Hui; Liu Li; Wang Gui-Ying; Xu Zhi-Zhan

2006-01-01

Surface-enhanced resonance Raman scattering (SERRS) of Rhodamine 6G (R6G) adsorbed on colloidal silver clusters has been studied. Based on the great enhancement of the Raman signal and the quench of the fluorescence, the SERRS spectra of R6G were recorded for the samples of dye colloidal solution with different concentrations. Spectral inhomogeneity behaviours from single molecules in the dried sample films were observed with complementary evidences, such as spectral polarization, spectral diffusion, intensity fluctuation of vibrational lines and even "breathing" of the molecules. Sequential spectra observed from a liquid sample with an average of 0.3 dye molecules in the probed volume exhibited the expected Poisson distribution for actually measuring 0, 1 or 2 molecules. Difference between the SERRS spectra of R6G excited by linearly and circularly polarized light were experimentally measured.

Enhancing Single Molecule Imaging in Optofluidics and Microfluidics

Directory of Open Access Journals (Sweden)

Andreas E. Vasdekis

2011-08-01

Full Text Available Microfluidics and optofluidics have revolutionized high-throughput analysis and chemical synthesis over the past decade. Single molecule imaging has witnessed similar growth, due to its capacity to reveal heterogeneities at high spatial and temporal resolutions. However, both resolution types are dependent on the signal to noise ratio (SNR of the image. In this paper, we review how the SNR can be enhanced in optofluidics and microfluidics. Starting with optofluidics, we outline integrated photonic structures that increase the signal emitted by single chromophores and minimize the excitation volume. Turning then to microfluidics, we review the compatible functionalization strategies that reduce noise stemming from non-specific interactions and architectures that minimize bleaching and blinking.

Signal Diversity of Receptor for Advanced Glycation End Products.

Science.gov (United States)

Sakaguchi, Masakiyo; Kinoshita, Rie; Putranto, Endy Widya; Ruma, I Made Winarsa; Sumardika, I Wayan; Youyi, Chen; Tomonobu, Naoko; Yamamoto, Ken-Ichi; Murata, Hitoshi

2017-12-01

The receptor for advanced glycation end products (RAGE) is involved in inflammatory pathogenesis. It functions as a receptor to multiple ligands such as AGEs, HMGB1 and S100 proteins, activating multiple intracellular signaling pathways with each ligand binding. The molecular events by which ligand-activated RAGE controls diverse signaling are not well understood, but some progress was made recently. Accumulating evidence revealed that RAGE has multiple binding partners within the cytoplasm and on the plasma membrane. It was first pointed out in 2008 that RAGE's cytoplasmic tail is able to recruit Diaphanous-1 (Dia-1), resulting in the acquisition of increased cellular motility through Rac1/Cdc42 activation. We also observed that within the cytosol, RAGE's cytoplasmic tail behaves similarly to a Toll-like receptor (TLR4)-TIR domain, interacting with TIRAP and MyD88 adaptor molecules that in turn activate multiple downstream signals. Subsequent studies demonstrated the presence of an alternative adaptor molecule, DAP10, on the plasma membrane. The coupling of RAGE with DAP10 is critical for enhancing the RAGE-mediated survival signal. Interestingly, RAGE interaction on the membrane was not restricted to DAP10 alone. The chemotactic G-protein-coupled receptors (GPCRs) formyl peptide receptors1 and 2 (FPR1 and FPR2) also interacted with RAGE on the plasma membrane. Binding interaction between leukotriene B4 receptor 1 (BLT1) and RAGE was also demonstrated. All of the interactions affected the RAGE signal polarity. These findings indicate that functional interactions between RAGE and various molecules within the cytoplasmic area or on the membrane area coordinately regulate multiple ligand-mediated RAGE responses, leading to typical cellular phenotypes in several pathological settings. Here we review RAGE's signaling diversity, to contribute to the understanding of the elaborate functions of RAGE in physiological and pathological contexts.

V773 Cas, QS Aql, AND BR Ind: ECLIPSING BINARIES AS PARTS OF MULTIPLE SYSTEMS

Energy Technology Data Exchange (ETDEWEB)

Zasche, P.; Juryšek, J.; Nemravová, J.; Wolf, M.; Korčáková, D. [Astronomical Institute, Charles University in Prague, Faculty of Mathematics and Physics, CZ-180 00, Praha 8, V Holešovičkách 2 (Czech Republic); Uhlař, R. [Private Observatory, Pohoří 71, CZ-254 01, Jílové u Prahy (Czech Republic); Svoboda, P. [Private Observatory, Výpustky 5, CZ-614 00, Brno (Czech Republic); Hoňková, K. [Variable Star and Exoplanet Section of Czech Astronomical Society, Vsetínská 941/78, CZ-757 01, Valašské Meziříčí (Czech Republic); Mašek, M.; Prouza, M. [Institute of Physics, The Czech Academy of Sciences, Na Slovance 1999/2, CZ-182 21, Praha (Czech Republic); Čechura, J.; Šlechta, M., E-mail: zasche@sirrah.troja.mff.cuni.cz [Astronomical Institute, The Czech Academy of Sciences, CZ-251 65, Ondřejov (Czech Republic)

2017-01-01

Eclipsing binaries remain crucial objects for our understanding of the universe. In particular, those that are components of multiple systems can help us solve the problem of the formation of these systems. Analysis of the radial velocities together with the light curve produced for the first time precise physical parameters of the components of the multiple systems V773 Cas, QS Aql, and BR Ind. Their visual orbits were also analyzed, which resulted in slightly improved orbital elements. What is typical for all these systems is that their most dominant source is the third distant component. The system V773 Cas consists of two similar G1-2V stars revolving in a circular orbit and a more distant component of the A3V type. Additionally, the improved value of parallax was calculated to be 17.6 mas. Analysis of QS Aql resulted in the following: the inner eclipsing pair is composed of B6V and F1V stars, and the third component is of about the B6 spectral type. The outer orbit has high eccentricity of about 0.95, and observations near its upcoming periastron passage between the years 2038 and 2040 are of high importance. Also, the parallax of the system was derived to be about 2.89 mas, moving the star much closer to the Sun than originally assumed. The system BR Ind was found to be a quadruple star consisting of two eclipsing K dwarfs orbiting each other with a period of 1.786 days; the distant component is a single-lined spectroscopic binary with an orbital period of about 6 days. Both pairs are moving around each other on their 148 year orbit.

Endophytic Actinomycetes: A Novel Source of Potential Acyl Homoserine Lactone Degrading Enzymes

Directory of Open Access Journals (Sweden)

Surang Chankhamhaengdecha

2013-01-01

Full Text Available Several Gram-negative pathogenic bacteria employ N-acyl-L-homoserine lactone (HSL quorum sensing (QS system to control their virulence traits. Degradation of acyl-HSL signal molecules by quorum quenching enzyme (QQE results in a loss of pathogenicity in QS-dependent organisms. The QQE activity of actinomycetes in rhizospheric soil and inside plant tissue was explored in order to obtain novel strains with high HSL-degrading activity. Among 344 rhizospheric and 132 endophytic isolates, 127 (36.9% and 68 (51.5% of them, respectively, possessed the QQE activity. The highest HSL-degrading activity was at 151.30±3.1 nmole/h/mL from an endophytic actinomycetes isolate, LPC029. The isolate was identified as Streptomyces based on 16S  rRNA gene sequence similarity. The QQE from LPC029 revealed HSL-acylase activity that was able to cleave an amide bond of acyl-side chain in HSL substrate as determined by HPLC. LPC029 HSL-acylase showed broad substrate specificity from C6- to C12-HSL in which C10HSL is the most favorable substrate for this enzyme. In an in vitro pathogenicity assay, the partially purified HSL-acylase efficiently suppressed soft rot of potato caused by Pectobacterium carotovorum ssp. carotovorum as demonstrated. To our knowledge, this is the first report of HSL-acylase activity derived from an endophytic Streptomyces.

Roles of STATs signaling in cardiovascular diseases.

Science.gov (United States)

Kishore, Raj; Verma, Suresh K

2012-04-01

In cardiac and many other systems, chronic stress activates avfamily of structurally and functionally conserved receptors and their downstream signaling molecules that entail tyrosine, serine or threonine phosphorylation to transfer the messages to the genetic machinery. However, the activation of the Janus kinases (JAKs) and their downstream signal transducer and activator of transcription (STATs) proteins is both characteristic of and unique to cytokine and growth factor signaling which plays a central role in heart physiology. Dysregulation of JAK-STAT signaling is associated with various cardiovascular diseases. The molecular signaling and specificity of the JAK-STAT pathway are modulated at many levels by distinct regulatory proteins. Here, we review recent studies on the regulation of the STAT signaling pathway that will enhance our ability to design rational therapeutic strategies for stress-induced heart failure.

Nitric oxide in denitrification - an elusive signal molecule emitted from soil

Science.gov (United States)

Bakken, L. R.; Frostegard, A.

2010-12-01

Soils emit variable amounts of NO and N2O, with environmental consequences (atmosphere chemistry and global warming). Nitrification was for some time considered the main source of NO emission, but several investigations have indicated that denitrification may be a potent source as well. However, strong emission of NO from denitrifying organisms is in some conflict with common understanding of the role of NO in the regulation of denitrification, as based on paradigm model strains. NO appears to be an important signal molecule for denitrifying organisms by exerting a positive feedback on the expression of the genes coding for denitrification. On the other hand, a careful control of the NO concentrations at nanomolar concentrations has long been considered an essential fitness character for denitrifying organisms, since micromolar concentrations of NO is toxic to many organisms. For the same reason, organisms lacking genes encoding NO reductase (NOR) have been considered unfit for denitrification. This view is challenged by isolation of organisms whose primary product of denitrification is NO, either because they lack the genes for NO reductase, or because their synthesis of the denitrification proteome is extremely unbalanced, resulting in transient NO accumulation to micromolar concentrations when grown in pure culture. Such paralyzing NO concentrations are probably never reached in natural environments, however, due to diffusion and NO-absorption by adjacent organisms, be it by NOR or other NO scavenging enzymes. Hypothetically, the production of NO by denitrifying organisms may be an advantage by fending off nearby competitors. We have embarked on a comparative study of denitrification phenotypes regarding their denitrification gene expression and control of NO and N2O concentrations in response to anoxic spells. This includes model strains (Paracoccus denitrificans and Agrobacterium tumefaciens) and recently isolated strains within several genera. Some are found

Control of density-dependent, cell state-specific signal transduction by the cell adhesion molecule CEACAM1, and its influence on cell cycle regulation

International Nuclear Information System (INIS)

Scheffrahn, Inka; Singer, Bernhard B.; Sigmundsson, Kristmundur; Lucka, Lothar; Oebrink, Bjoern

2005-01-01

Growth factor receptors, extracellular matrix receptors, and cell-cell adhesion molecules co-operate in regulating the activities of intracellular signaling pathways. Here, we demonstrate that the cell adhesion molecule CEACAM1 co-regulates growth-factor-induced DNA synthesis in NBT-II epithelial cells in a cell-density-dependent manner. CEACAM1 exerted its effects by regulating the activity of the Erk 1/2 MAP kinase pathway and the expression levels of the cyclin-dependent kinase inhibitor p27 Kip1 . Interestingly, both inhibitory and stimulatory effects were observed. Confluent cells continuously exposed to fetal calf serum showed little Erk activity and DNA synthesis compared with sparse cells. Under these conditions, anti-CEACAM1 antibodies strongly stimulated Erk activation, decreased p27 expression, and induced DNA synthesis. In serum-starved confluent cells, re-addition of 10% fetal calf serum activated the Erk pathway, decreased p27 expression, and stimulated DNA synthesis to the same levels as in sparse cells. Under these conditions anti-CEACAM1 antibodies de-activated Erk, restored the level of p27, and inhibited DNA synthesis. These data indicate that CEACAM1 mediates contact inhibition of proliferation in cells that are constantly exposed to growth factors, but co-activates growth-factor-induced proliferation in cells that have been starved for growth factors; exposure to extracellular CEACAM1 ligands reverts these responses

Production of acyl-homoserine lactone quorum-sensing signals is widespread in gram-negative Methylobacterium.

Science.gov (United States)

Poonguzhali, Selvaraj; Madhaiyan, Munusamy; Sa, Tongmin

2007-02-01

Members of Methylobacterium, referred as pink-pigmented facultative methylotrophic bacteria, are frequently associated with terrestrial and aquatic plants, tending to form aggregates on the phyllosphere. We report here that the production of autoinducer molecules involved in the cell-to-cell signaling process, which is known as quorum sensing, is common among Methylobacterium species. Several strains of Methylobacterium were tested for their ability to produce N-acyl-homoserine lactone (AHL) signal molecules using different indicators. Most strains of Methylobacterium tested could elicit a positive response in Agrobacterium tumefaciens harboring lacZ fused to a gene that is regulated by autoinduction. The synthesis of these compounds was cell-density dependent, and the maximal activity was reached during the late exponential to stationary phases. The bacterial extracts were separated by thin-layer chromatography and bioassayed with A. tumefaciens NT1 (traR, tra::lacZ749). They revealed the production of various patterns of the signal molecules, which are strain dependent. At least two signal molecules could be detected in most of the strains tested, and comparison of their relative mobilities suggested that they are homologs of N-octanoyl-DL-homoserine lactone (C8-HSL) and N-decanoyl-DL-homoserine lactone (C10-HSL).

Signaling events during initiation of arbuscular mycorrhizal symbiosis.

Science.gov (United States)

Schmitz, Alexa M; Harrison, Maria J

2014-03-01

Under nutrient-limiting conditions, plants will enter into symbiosis with arbuscular mycorrhizal (AM) fungi for the enhancement of mineral nutrient acquisition from the surrounding soil. AM fungi live in close, intracellular association with plant roots where they transfer phosphate and nitrogen to the plant in exchange for carbon. They are obligate fungi, relying on their host as their only carbon source. Much has been discovered in the last decade concerning the signaling events during initiation of the AM symbiosis, including the identification of signaling molecules generated by both partners. This signaling occurs through symbiosis-specific gene products in the host plant, which are indispensable for normal AM development. At the same time, plants have adapted complex mechanisms for avoiding infection by pathogenic fungi, including an innate immune response to general microbial molecules, such as chitin present in fungal cell walls. How it is that AM fungal colonization is maintained without eliciting a defensive response from the host is still uncertain. In this review, we present a summary of the molecular signals and their elicited responses during initiation of the AM symbiosis, including plant immune responses and their suppression. © 2014 Institute of Botany, Chinese Academy of Sciences.

A bioinformatic survey of distribution, conservation, and probable functions of LuxR solo regulators in bacteria

Science.gov (United States)

Subramoni, Sujatha; Florez Salcedo, Diana Vanessa; Suarez-Moreno, Zulma R.

2015-01-01

LuxR solo transcriptional regulators contain both an autoinducer binding domain (ABD; N-terminal) and a DNA binding Helix-Turn-Helix domain (HTH; C-terminal), but are not associated with a cognate N-acyl homoserine lactone (AHL) synthase coding gene in the same genome. Although a few LuxR solos have been characterized, their distributions as well as their role in bacterial signal perception and other processes are poorly understood. In this study we have carried out a systematic survey of distribution of all ABD containing LuxR transcriptional regulators (QS domain LuxRs) available in the InterPro database (IPR005143), and identified those lacking a cognate AHL synthase. These LuxR solos were then analyzed regarding their taxonomical distribution, predicted functions of neighboring genes and the presence of complete AHL-QS systems in the genomes that carry them. Our analyses reveal the presence of one or multiple predicted LuxR solos in many proteobacterial genomes carrying QS domain LuxRs, some of them harboring genes for one or more AHL-QS circuits. The presence of LuxR solos in bacteria occupying diverse environments suggests potential ecological functions for these proteins beyond AHL and interkingdom signaling. Based on gene context and the conservation levels of invariant amino acids of ABD, we have classified LuxR solos into functionally meaningful groups or putative orthologs. Surprisingly, putative LuxR solos were also found in a few non-proteobacterial genomes which are not known to carry AHL-QS systems. Multiple predicted LuxR solos in the same genome appeared to have different levels of conservation of invariant amino acid residues of ABD questioning their binding to AHLs. In summary, this study provides a detailed overview of distribution of LuxR solos and their probable roles in bacteria with genome sequence information. PMID:25759807

A bioinformatic survey of distribution, conservation, and probable functions of LuxR solo regulators in bacteria.

Science.gov (United States)

Subramoni, Sujatha; Florez Salcedo, Diana Vanessa; Suarez-Moreno, Zulma R

2015-01-01

LuxR solo transcriptional regulators contain both an autoinducer binding domain (ABD; N-terminal) and a DNA binding Helix-Turn-Helix domain (HTH; C-terminal), but are not associated with a cognate N-acyl homoserine lactone (AHL) synthase coding gene in the same genome. Although a few LuxR solos have been characterized, their distributions as well as their role in bacterial signal perception and other processes are poorly understood. In this study we have carried out a systematic survey of distribution of all ABD containing LuxR transcriptional regulators (QS domain LuxRs) available in the InterPro database (IPR005143), and identified those lacking a cognate AHL synthase. These LuxR solos were then analyzed regarding their taxonomical distribution, predicted functions of neighboring genes and the presence of complete AHL-QS systems in the genomes that carry them. Our analyses reveal the presence of one or multiple predicted LuxR solos in many proteobacterial genomes carrying QS domain LuxRs, some of them harboring genes for one or more AHL-QS circuits. The presence of LuxR solos in bacteria occupying diverse environments suggests potential ecological functions for these proteins beyond AHL and interkingdom signaling. Based on gene context and the conservation levels of invariant amino acids of ABD, we have classified LuxR solos into functionally meaningful groups or putative orthologs. Surprisingly, putative LuxR solos were also found in a few non-proteobacterial genomes which are not known to carry AHL-QS systems. Multiple predicted LuxR solos in the same genome appeared to have different levels of conservation of invariant amino acid residues of ABD questioning their binding to AHLs. In summary, this study provides a detailed overview of distribution of LuxR solos and their probable roles in bacteria with genome sequence information.

A bioinformatic survey of distribution, conservation and probable functions of LuxR solo regulators in bacteria

Directory of Open Access Journals (Sweden)

Sujatha eSubramoni

2015-02-01

Full Text Available LuxR solo transcriptional regulators contain both an autoinducer binding domain (ABD; N-terminal and a DNA binding Helix-Turn-Helix domain (HTH; C-terminal, but are not associated with a cognate N-acyl homoserine lactone (AHL synthase coding gene in the same genome. Although a few LuxR solos have been characterized, their distributions as well as their role in bacterial signal perception and other processes are poorly understood. In this study we have carried out a systematic survey of distribution of all ABD containing LuxR transcriptional regulators (QS domain LuxRs available in the InterPro database (IPR005143, and identified those lacking a cognate AHL synthase. These LuxR solos were then analyzed regarding their taxonomical distribution, predicted functions of neighboring genes and the presence of complete AHL-QS systems in the genomes that carry them. Our analyses reveal the presence of one or multiple predicted LuxR solos in many proteobacterial genomes carrying QS domain LuxRs, some of them harboring genes for one or more AHL-QS circuits. The presence of LuxR solos in bacteria occupying diverse environments suggests potential ecological functions for these proteins beyond AHL and interkingdom signaling. Based on gene context and the conservation levels of invariant amino acids of ABD, we have classified LuxR solos into functionally meaningful groups or putative orthologs. Surprisingly, putative LuxR solos were also found in a few non-proteobacterial genomes which are not known to carry AHL-QS systems. Multiple predicted LuxR solos in the same genome appeared to have different levels of conservation of invariant amino acid residues of ABD questioning their binding to AHLs. In summary, this study provides a detailed overview of distribution of LuxR solos and their probable roles in bacteria with genome sequence information.

Methods for the selective detection of alkyne-presenting molecules and related compositions and systems

Science.gov (United States)

Valdez, Carlos A.; Vu, Alexander K.

2017-10-17

Provided herein are methods for selectively detecting an alkyne-presenting molecule in a sample and related detection reagents, compositions, methods and systems. The methods include contacting a detection reagent with the sample for a time and under a condition to allow binding of the detection reagent to the one or more alkyne-presenting molecules possibly present in the matrix to the detection reagent. The detection reagent includes an organic label moiety presenting an azide group. The binding of the azide group to the alkyne-presenting molecules results in emission of a signal from the organic label moiety.

Deuterium-labelled N-acyl-l-homoserine lactones (AHLs) - inter-kingdom signalling molecules - synthesis, structural studies, and interactions with model lipid membranes

International Nuclear Information System (INIS)

Jakubczyk, Dorota; Barth, Christoph; Anastassacos, Frances; Koelsch, Patrick; Schepers, Ute; Kubas, Adam; Fink, Karin; Brenner-Weiss, Gerald; Braese, Stefan

2012-01-01

N-Acyl-l-homoserine lactones (AHLs) are synthesized by Gram-negative bacteria. These quorum-sensing molecules play an important role in the context of bacterial infection and biofilm formation. They also allow communication between microorganisms and eukaryotic cells (inter-kingdom signalling). However, very little is known about the entire mechanism of those interactions. Precise structural studies are required to analyse the different AHL isomers as only one form is biologically most active. Theoretical studies combined with experimental infrared and Raman spectroscopic data are therefore undertaken to characterise the obtained compounds. To mimic interactions between AHL and cell membranes, we studied the insertion of AHL in supported lipid bilayers, using vibrational sum-frequency-generation spectroscopy. Deuterium-labelled AHLs were thus synthesized. Starting from readily available deuterated fatty acids, a two-step procedure towards deuterated N-acyl-l-homoserine lactones with varying chain lengths is described. This included the acylation of Meldrum's acid followed by amidation. Additionally, the detailed analytical evaluation of the products is presented herein. (orig.)

madSTORM: a superresolution technique for large-scale multiplexing at single-molecule accuracy

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Yi, Jason; Manna, Asit; Barr, Valarie A.; Hong, Jennifer; Neuman, Keir C.; Samelson, Lawrence E.

2016-01-01

Investigation of heterogeneous cellular structures using single-molecule localization microscopy has been limited by poorly defined localization accuracy and inadequate multiplexing capacity. Using fluorescent nanodiamonds as fiducial markers, we define and achieve localization precision required for single-molecule accuracy in dSTORM images. Coupled with this advance, our new multiplexing strategy, madSTORM, allows accurate targeting of multiple molecules using sequential binding and elution of fluorescent antibodies. madSTORM is used on an activated T-cell to localize 25 epitopes, 14 of which are on components of the same multimolecular T-cell receptor complex. We obtain an average localization precision of 2.6 nm, alignment error of 2.0 nm, and molecules within structures. Probing the molecular topology of complex signaling cascades and other heterogeneous networks is feasible with madSTORM. PMID:27708141

Iron is a signal for Stenotrophomonas maltophilia biofilm formation, oxidative stress response, OMPs expression and virulence

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Carlos Adrian Garcia

2015-09-01

Full Text Available Stenotrophomonas maltophilia is an emerging nosocomial pathogen. In many bacteria iron availability regulates, trough the Fur system, not only iron homeostasis but also virulence. The aim of this work was to assess the role of iron on S. maltophilia biofilm formation, EPS production, oxidative stress response, OMPs regulation, quorum sensing (QS, and virulence. Studies were done on K279 and its isogenic fur mutant F60 cultured in the presence or absence of dipyridyl. This is the first report of spontaneous fur mutants obtained in S. maltophilia. F60 produced higher amounts of biofilms than K279a and CLSM analysis demonstrated improved adherence and biofilm organization. Under iron restricted conditions, K279a produced biofilms with more biomass and enhanced thickness. In addition, F60 produced higher amounts of EPS than K279a but with a similar composition, as revealed by ATR-FTIR spectroscopy. With respect to the oxidative stress response, MnSOD was the only SOD isoenzyme detected in K279a. F60 presented higher SOD activity than the wt strain in planktonic and biofilm cultures, and iron deprivation increased K279a SOD activity. Under iron starvation, SDS-PAGE profile from K279a presented two iron-repressed proteins. Mass spectrometry analysis revealed homology with FepA and another putative TonB-dependent siderophore receptor of K279a. In silico analysis allowed the detection of potential Fur boxes in the respective coding genes. K279a encodes the QS diffusible signal factor (DSF. Under iron restriction K279a produced higher amounts of DSF than under iron rich condition. Finally, F60 was more virulent than K279a in the Galleria mellonella killing assay. These results put in evidence that iron levels regulate, likely through the Fur system, S. maltophilia biofilm formation, oxidative stress response, OMPs expression, DSF production and virulence.

Pseudomonas aeruginosa Biofilms

DEFF Research Database (Denmark)

Alhede, Maria; Bjarnsholt, Thomas; Givskov, Michael

2014-01-01

biofilms, which protect the aggregated, biopolymer-embedded bacteria from the detrimental actions of antibiotic treatments and host immunity. A key component in the protection against innate immunity is rhamnolipid, which is a quorum sensing (QS)-regulated virulence factor. QS is a cell-to-cell signaling...... mechanism used to coordinate expression of virulence and protection of aggregated biofilm cells. Rhamnolipids are known for their ability to cause hemolysis and have been shown to cause lysis of several cellular components of the human immune system, for example, macrophages and polymorphonuclear leukocytes...

Carbon monoxide may be an important molecule in migraine and other headaches

DEFF Research Database (Denmark)

Arngrim, Nanna; Schytz, Henrik W; Hauge, Mette K

2014-01-01

INTRODUCTION: Carbon monoxide was previously considered to just be a toxic gas. A wealth of recent information has, however, shown that it is also an important endogenously produced signalling molecule involved in multiple biological processes. Endogenously produced carbon monoxide may thus play...

Effect of the signaling lymphocytic activation molecule (SLAM in the modulation of T cells in immune response to Leishmania braziliensis in vitro

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Zirlane Castelo Branco Coêlho

2017-02-01

Full Text Available Introduction: Signaling lymphocyte activation molecule (SLAM is a self-ligand receptor on the surface of activated T- and B-lymphocytes, macrophages, and DC. Studies have shown PBMC from healthy individuals exposed to Leishmania differ in IFN-γ production. Objective: We investigated the role of SLAM signaling pathway in PMBC from high (HP and low (LP IFN-γ producers exposed to L. braziliensis in vitro. Methods: PBMC from 43 healthy individuals were cultured with or without antigen, α-SLAM, rIL-12 and rIFN-γ. The cytokines production was evaluated by ELISA, and SLAM expression by flow cytometry. Results: L. braziliensis associated with rIFN-γ or rIL-12 reduced early SLAM but did not modify this response later in HP. α-SLAM did not alter CD3+SLAM+ expression, and not affected IFN-γ and IL-13 production, in both groups, but increased significantly IL-10 in HP. Leishmania associated with α-SLAM and rIL-12 increased IFN-γ in LP, as well as IL-13 in HP. LP group presented low IFN-γ and IL-13 production, and low SLAM expression. Conclusion: Collectively, these findings suggest that when PBMC from healthy individuals are sensitized with L. braziliensis in vitro, SLAM acts in modulating Th1 response in HP individuals and induces a condition of immunosuppression in LP individuals.

Proteomics of the bacterial cross-talk by quorum sensing.

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Di Cagno, Raffaella; De Angelis, Maria; Calasso, Maria; Gobbetti, Marco

2011-01-01

Words such as language and behavior are frequently used to depict "quorum sensing" (QS) in the literature. Simplifying the concept, language and cross-talk between bacteria, and between bacteria and animal or plants hosts determine the behavior (e.g., beneficial or pathogenic effects). Genomics and transcriptomics were the principal approaches used to study the multiple mechanisms of QS. Nevertheless, sequencing of genomes paved the way for another approach which consists on comparative and functional proteomics. This review aims at describing how the proteomic dictionary translates: (i) the languages (N-acyl-L-homoserine lactones, AHL; autoinducing peptide, AIP; autoinducer-2, AI-2) used by bacteria to communicate; (ii) signals of QS which induce various phenotypes (e.g., virulence, biofilm maturation); (iii) cross-talk between lactic acid bacteria within various food ecosystems (e.g. sourdough and fermented milk); (iv) probiotic messages at intra- and inter-species and interkingdom levels; and (v) words for quorum quenching (QQ). Proteomics is an indispensible discipline to elucidate the mechanisms of regulation of the multitude of language signals which diffuse through different microbial communities. Copyright © 2010 Elsevier B.V. All rights reserved.

Total internal reflection sum-frequency generation spectroscopy and dense gold nanoparticles monolayer: a route for probing adsorbed molecules

International Nuclear Information System (INIS)

Tourillon, Gerard; Dreesen, Laurent; Volcke, Cedric; Sartenaer, Yannick; Thiry, Paul A; Peremans, Andre

2007-01-01

We show that sum-frequency generation spectroscopy performed in the total internal reflection configuration (TIR-SFG) combined with a dense gold nanoparticles monolayer allows us to study, with an excellent signal to noise ratio and high signal to background ratio, the conformation of adsorbed molecules. Dodecanethiol (DDT) was used as probe molecules in order to assess the potentialities of the approach. An enhancement of more than one order of magnitude of the SFG signals arising from the adsorbed species is observed with the TIR geometry compared to the external reflection one while the SFG non-resonant contribution remains the same for both configurations. Although further work is required to fully understand the origin of the SFG process on nanoparticles, our work opens new possibilities for studying nanostructures

Nasal chemosensory cells use bitter taste signaling to detect irritants and bacterial signals.

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Tizzano, Marco; Gulbransen, Brian D; Vandenbeuch, Aurelie; Clapp, Tod R; Herman, Jake P; Sibhatu, Hiruy M; Churchill, Mair E A; Silver, Wayne L; Kinnamon, Sue C; Finger, Thomas E

2010-02-16

The upper respiratory tract is continually assaulted with harmful dusts and xenobiotics carried on the incoming airstream. Detection of such irritants by the trigeminal nerve evokes protective reflexes, including sneezing, apnea, and local neurogenic inflammation of the mucosa. Although free intra-epithelial nerve endings can detect certain lipophilic irritants (e.g., mints, ammonia), the epithelium also houses a population of trigeminally innervated solitary chemosensory cells (SCCs) that express T2R bitter taste receptors along with their downstream signaling components. These SCCs have been postulated to enhance the chemoresponsive capabilities of the trigeminal irritant-detection system. Here we show that transduction by the intranasal solitary chemosensory cells is necessary to evoke trigeminally mediated reflex reactions to some irritants including acyl-homoserine lactone bacterial quorum-sensing molecules, which activate the downstream signaling effectors associated with bitter taste transduction. Isolated nasal chemosensory cells respond to the classic bitter ligand denatonium as well as to the bacterial signals by increasing intracellular Ca(2+). Furthermore, these same substances evoke changes in respiration indicative of trigeminal activation. Genetic ablation of either G alpha-gustducin or TrpM5, essential elements of the T2R transduction cascade, eliminates the trigeminal response. Because acyl-homoserine lactones serve as quorum-sensing molecules for gram-negative pathogenic bacteria, detection of these substances by airway chemoreceptors offers a means by which the airway epithelium may trigger an epithelial inflammatory response before the bacteria reach population densities capable of forming destructive biofilms.

Metabolites in vertebrate Hedgehog signaling.

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Roberg-Larsen, Hanne; Strand, Martin Frank; Krauss, Stefan; Wilson, Steven Ray

2014-04-11

The Hedgehog (HH) signaling pathway is critical in embryonic development, stem cell biology, tissue homeostasis, chemoattraction and synapse formation. Irregular HH signaling is associated with a number of disease conditions including congenital disorders and cancer. In particular, deregulation of HH signaling has been linked to skin, brain, lung, colon and pancreatic cancers. Key mediators of the HH signaling pathway are the 12-pass membrane protein Patched (PTC), the 7-pass membrane protein Smoothened (SMO) and the GLI transcription factors. PTC shares homology with the RND family of small-molecule transporters and it has been proposed that it interferes with SMO through metabolites. Although a conclusive picture is lacking, substantial efforts are made to identify and understand natural metabolites/sterols, including cholesterol, vitamin D3, oxysterols and glucocorticoides, that may be affected by, or influence the HH signaling cascade at the level of PTC and SMO. In this review we will elaborate the role of metabolites in HH signaling with a focus on oxysterols, and discuss advancements in modern analytical approaches in the field. Copyright © 2014 Elsevier Inc. All rights reserved.

Unraveling the cellular context of cyclic nucleotide signaling proteins by chemical proteomics

NARCIS (Netherlands)

Corradini, E.

2015-01-01

Understanding the molecular mechanisms which regulate signal transduction is fundamental to the development of therapeutic molecules for the treatment of several diseases. In particular, signaling proteins, such as cyclic nucleotide dependent enzymes are the orchestrators of many tissue functions.

Probing the local environment of a single OPE3 molecule using inelastic tunneling electron spectroscopy.

Science.gov (United States)

Frisenda, Riccardo; Perrin, Mickael L; van der Zant, Herre S J

2015-01-01

We study single-molecule oligo(phenylene ethynylene)dithiol junctions by means of inelastic electron tunneling spectroscopy (IETS). The molecule is contacted with gold nano-electrodes formed with the mechanically controllable break junction technique. We record the IETS spectrum of the molecule from direct current measurements, both as a function of time and electrode separation. We find that for fixed electrode separation the molecule switches between various configurations, which are characterized by different IETS spectra. Similar variations in the IETS signal are observed during atomic rearrangements upon stretching of the molecular junction. Using quantum chemistry calculations, we identity some of the vibrational modes which constitute a chemical fingerprint of the molecule. In addition, changes can be attributed to rearrangements of the local molecular environment, in particular at the molecule-electrode interface. This study shows the importance of taking into account the interaction with the electrodes when describing inelastic contributions to transport through single-molecule junctions.

Growing interstellar molecules with ion-molecule reactions

International Nuclear Information System (INIS)

Bohme, D.K.

1989-01-01

Laboratory measurements of gas-phase ion-molecule reactions continue to provide important insights into the chemistry of molecular growth in interstellar environments. It is also true that the measurements are becoming more demanding as larger molecules capture our interest. While some of these measurements are motivated by current developments in chemical models of interstellar environments or by new molecular observations by astronomers, others explore novel chemistry which can lead to predictions of new interstellar molecules. Here the author views the results of some recent measurements, taken in the Ion Chemistry Laboratory at York University with the SIFT technique, which address some of the current needs of modellers and observers and which also provide some new fundamental insight into molecular growth, particularly when it occurs in the presence of large molecules such as PAH molecules which are now thought to have a major influence on the chemistry of interstellar environments in which they are present

Exploring in vivo cholesterol-mediated interactions between activated EGF receptors in plasma membrane with single-molecule optical tracking

International Nuclear Information System (INIS)

Lin, Chien Y.; Huang, Jung Y.; Lo, Leu-Wei

2016-01-01

The first step in many cellular signaling processes occurs at various types of receptors in the plasma membrane. Membrane cholesterol can alter these signaling pathways of living cells. However, the process in which the interaction of activated receptors is modulated by cholesterol remains unclear. In this study, we measured single-molecule optical trajectories of epidermal growth factor receptors moving in the plasma membranes of two cancerous cell lines and one normal endothelial cell line. A stochastic model was developed and applied to identify critical information from single-molecule trajectories. We discovered that unliganded epidermal growth factor receptors may reside nearby cholesterol-riched regions of the plasma membrane and can move into these lipid domains when subjected to ligand binding. The amount of membrane cholesterol considerably affects the stability of correlated motion of activated epidermal growth factor receptors. Our results provide single-molecule evidence of membrane cholesterol in regulating signaling receptors. Because the three cell lines used for this study are quite diverse, our results may be useful to shed light on the mechanism of cholesterol-mediated interaction between activated receptors in live cells

Role of the interplay between quorum sensing regulator VqsR and the Pseudomonas quinolone signal in mediating carbapenem tolerance in Pseudomonas aeruginosa.

Science.gov (United States)

Viducic, Darija; Murakami, Keiji; Amoh, Takashi; Ono, Tsuneko; Miyake, Yoichiro

2017-06-01

Pseudomonas aeruginosa coordinates its response to environmental conditions through activation of a quorum sensing (QS) system. In this study, we investigated the regulatory interaction between the QS transcriptional regulator VqsR and the Pseudomonas quinolone signal (PQS) through integration of sigma factor RpoS, and we addressed whether one of the pathways controlling carbapenem tolerance can be attributed to VqsR. We demonstrate that vqsR expression at the transcriptional level is regulated by pqsA, pqsR, and pqsE. Assessment of the transcriptional expression of vqsR, lasI, rhlI, and qscR in ΔpqsA and ΔpqsAΔrpoS mutants provided insight into pqsA- and rpoS-dependent regulation of vqsR and vqsR-controlled genes. Exogenously supplemented PQS reversed expression of vqsR and vqsR-controlled genes in the ΔpqsA mutant to wild-type levels, but failed to increase expression levels of lasI and qscR in the ΔpqsAΔrpoS mutant to levels observed in wild-type PAO1. The ΔvqsR mutant showed reduced survival when challenged with carbapenems compared to wild-type PAO1. Introduction of a pqsA mutation into the ΔvqsR mutant completely abolished its carbapenem-sensitive phenotype. We conclude that a regulatory link between PQS and vqsR exists, and that RpoS is important in their interaction. We also demonstrate that VqsR affects carbapenem tolerance. Copyright © 2017 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.

Food as a Source for Quorum Sensing Inhibitors: Iberin from Horseradish Revealed as a Quorum Sensing Inhibitor of Pseudomonas aeruginosa

DEFF Research Database (Denmark)

Jakobsen, Tim Holm; Bragason, Steinn Kristinn; Phipps, Richard Kerry

2012-01-01

of traditional antibiotics to treat infections caused by bacterial biofilms and multidrug-resistant bacteria. Several QSIs of natural origin have been identified, and in this study, several common food products and plants were extracted and screened for QSI activity in an attempt to isolate and characterize...... to transcend problems with selective pressures for antibiotic resistance, is to interrupt bacterial communication, also known as quorum sensing (QS), by means of signal antagonists, the so-called QS inhibitors (QSIs). Furthermore, QSI agents offer a potential solution to the deficiencies associated with use......-diode array detector-mass spectrometry (LC-DAD-MS) and nuclear magnetic resonance (NMR) spectroscopy as iberin—an isothiocyanate produced by many members of the Brassicaceae family. Real-time PCR (RT-PCR) and DNA microarray studies showed that iberin specifically blocks expression of QS-regulated genes in P...

Design principles of nuclear receptor signaling: how complex networking improves signal transduction

Science.gov (United States)

Kolodkin, Alexey N; Bruggeman, Frank J; Plant, Nick; Moné, Martijn J; Bakker, Barbara M; Campbell, Moray J; van Leeuwen, Johannes P T M; Carlberg, Carsten; Snoep, Jacky L; Westerhoff, Hans V

2010-01-01

The topology of nuclear receptor (NR) signaling is captured in a systems biological graphical notation. This enables us to identify a number of ‘design' aspects of the topology of these networks that might appear unnecessarily complex or even functionally paradoxical. In realistic kinetic models of increasing complexity, calculations show how these features correspond to potentially important design principles, e.g.: (i) cytosolic ‘nuclear' receptor may shuttle signal molecules to the nucleus, (ii) the active export of NRs may ensure that there is sufficient receptor protein to capture ligand at the cytoplasmic membrane, (iii) a three conveyor belts design dissipating GTP-free energy, greatly aids response, (iv) the active export of importins may prevent sequestration of NRs by importins in the nucleus and (v) the unspecific nature of the nuclear pore may ensure signal-flux robustness. In addition, the models developed are suitable for implementation in specific cases of NR-mediated signaling, to predict individual receptor functions and differential sensitivity toward physiological and pharmacological ligands. PMID:21179018

Fabrication of Low Noise Borosilicate Glass Nanopores for Single Molecule Sensing.

Directory of Open Access Journals (Sweden)

Jayesh A Bafna

Full Text Available We show low-cost fabrication and characterization of borosilicate glass nanopores for single molecule sensing. Nanopores with diameters of ~100 nm were fabricated in borosilicate glass capillaries using laser assisted glass puller. We further achieve controlled reduction and nanometer-size control in pore diameter by sculpting them under constant electron beam exposure. We successfully fabricate pore diameters down to 6 nm. We next show electrical characterization and low-noise behavior of these borosilicate nanopores and compare their taper geometries. We show, for the first time, a comprehensive characterization of glass nanopore conductance across six-orders of magnitude (1M-1μM of salt conditions, highlighting the role of buffer conditions. Finally, we demonstrate single molecule sensing capabilities of these devices with real-time translocation experiments of individual λ-DNA molecules. We observe distinct current blockage signatures of linear as well as folded DNA molecules as they undergo voltage-driven translocation through the glass nanopores. We find increased signal to noise for single molecule detection for higher trans-nanopore driving voltages. We propose these nanopores will expand the realm of applications for nanopore platform.

TSLP signaling pathway map: a platform for analysis of TSLP-mediated signaling.

Science.gov (United States)

Zhong, Jun; Sharma, Jyoti; Raju, Rajesh; Palapetta, Shyam Mohan; Prasad, T S Keshava; Huang, Tai-Chung; Yoda, Akinori; Tyner, Jeffrey W; van Bodegom, Diederik; Weinstock, David M; Ziegler, Steven F; Pandey, Akhilesh

2014-01-01

Thymic stromal lymphopoietin (TSLP) is a four-helix bundle cytokine that plays a critical role in the regulation of immune responses and in the differentiation of hematopoietic cells. TSLP signals through a heterodimeric receptor complex consisting of an interleukin-7 receptor α chain and a unique TSLP receptor (TSLPR) [also known as cytokine receptor-like factor 2 (CRLF2)]. Cellular targets of TSLP include dendritic cells, B cells, mast cells, regulatory T (Treg) cells and CD4+ and CD8+ T cells. The TSLP/TSLPR axis can activate multiple signaling transduction pathways including the JAK/STAT pathway and the PI-3 kinase pathway. Aberrant TSLP/TSLPR signaling has been associated with a variety of human diseases including asthma, atopic dermatitis, nasal polyposis, inflammatory bowel disease, eosinophilic eosophagitis and, most recently, acute lymphoblastic leukemia. A centralized resource of the TSLP signaling pathway cataloging signaling events is not yet available. In this study, we present a literature-annotated resource of reactions in the TSLP signaling pathway. This pathway map is publicly available through NetPath (http://www.netpath.org/), an open access signal transduction pathway resource developed previously by our group. This map includes 236 molecules and 252 reactions that are involved in TSLP/TSLPR signaling pathway. We expect that the TSLP signaling pathway map will provide a rich resource to study the biology of this important cytokine as well as to identify novel therapeutic targets for diseases associated with dysregulated TSLP/TSLPR signaling. Database URL: http://www.netpath.org/pathways?path_id=NetPath_24.

Reverse engineering GTPase programming languages with reconstituted signaling networks.

Science.gov (United States)

Coyle, Scott M

2016-07-02

The Ras superfamily GTPases represent one of the most prolific signaling currencies used in Eukaryotes. With these remarkable molecules, evolution has built GTPase networks that control diverse cellular processes such as growth, morphology, motility and trafficking. (1-4) Our knowledge of the individual players that underlie the function of these networks is deep; decades of biochemical and structural data has provided a mechanistic understanding of the molecules that turn GTPases ON and OFF, as well as how those GTPase states signal by controlling the assembly of downstream effectors. However, we know less about how these different activities work together as a system to specify complex dynamic signaling outcomes. Decoding this molecular "programming language" would help us understand how different species and cell types have used the same GTPase machinery in different ways to accomplish different tasks, and would also provide new insights as to how mutations to these networks can cause disease. We recently developed a bead-based microscopy assay to watch reconstituted H-Ras signaling systems at work under arbitrary configurations of regulators and effectors. (5) Here we highlight key observations and insights from this study and propose extensions to our method to further study this and other GTPase signaling systems.

Charge-signal multiplication mediated by urea wires inside Y-shaped carbon nanotubes

International Nuclear Information System (INIS)

Lv, Mei; Liu, Zengrong; He, Bing; Xiu, Peng; Tu, Yusong

2014-01-01

In previous studies, we reported molecular dynamics (MD) simulations showing that single-file water wires confined inside Y-shaped single-walled carbon nanotubes (Y-SWNTs) held strong and robust capability to convert and multiply charge signals [Y. S. Tu, P. Xiu, R. Z. Wan, J. Hu, R. H. Zhou, and H. P. Fang, Proc. Natl. Acad. Sci. U.S.A. 106, 18120 (2009); Y. Tu, H. Lu, Y. Zhang, T. Huynh, and R. Zhou, J. Chem. Phys. 138, 015104 (2013)]. It is fascinating to see whether the signal multiplication can be realized by other kinds of polar molecules with larger dipole moments (which make the experimental realization easier). In this article, we use MD simulations to study the urea-mediated signal conversion and multiplication with Y-SWNTs. We observe that when a Y-SWNT with an external charge of magnitude 1.0 e (the model of a signal at the single-electron level) is solvated in 1 M urea solutions, urea can induce drying of the Y-SWNT and fill its interiors in single-file, forming Y-shaped urea wires. The external charge can effectively control the dipole orientation of the urea wire inside the main channel (i.e., the signal can be readily converted), and this signal can further be multiplied into 2 (or more) output signals by modulating dipole orientations of urea wires in bifurcated branch channels of the Y-SWNT. This remarkable signal transduction capability arises from the strong dipole-induced ordering of urea wires under extreme confinement. We also discuss the advantage of urea as compared with water in the signal multiplication, as well as the robustness and biological implications of our findings. This study provides the possibility for multiplying signals by using urea molecules (or other polar organic molecules) with Y-shaped nanochannels and might also help understand the mechanism behind signal conduction in both physical and biological systems

Wnt Signaling in Skeletal Muscle Development and Regeneration.

Science.gov (United States)

Girardi, Francesco; Le Grand, Fabien

2018-01-01

Wnt is a family of signaling molecules involved in embryogenesis, adult tissue repair, and cancer. They activate canonical and noncanonical Wnt signaling cascades in target cells. Several studies, within the last decades, showed that several Wnt ligands are involved in myogenesis and both canonical and noncanonical Wnt pathways regulate muscle formation and the maintenance of adult tissue homeostasis. In this review, we provide a comprehensive overview of the roles of Wnt signaling during muscle development and an updated description of Wnt functions during muscle repair. Lastly, we discuss the crosstalk between Wnt and TGFβ signaling pathways in skeletal muscle. Copyright © 2018 Elsevier Inc. All rights reserved.

Molecule nanoweaver

Science.gov (United States)

Gerald, II; Rex, E [Brookfield, IL; Klingler, Robert J [Glenview, IL; Rathke, Jerome W [Homer Glen, IL; Diaz, Rocio [Chicago, IL; Vukovic, Lela [Westchester, IL

2009-03-10

A method, apparatus, and system for constructing uniform macroscopic films with tailored geometric assemblies of molecules on the nanometer scale. The method, apparatus, and system include providing starting molecules of selected character, applying one or more force fields to the molecules to cause them to order and condense with NMR spectra and images being used to monitor progress in creating the desired geometrical assembly and functionality of molecules that comprise the films.

DRAGON, a GPI-anchored membrane protein, inhibits BMP signaling in C2C12 myoblasts.

Science.gov (United States)

Kanomata, Kazuhiro; Kokabu, Shoichiro; Nojima, Junya; Fukuda, Toru; Katagiri, Takenobu

2009-06-01

Bone morphogenetic proteins (BMPs) induce osteoblastic differentiation of myoblasts via binding to cell surface receptors. Repulsive guidance molecules (RGMs) have been identified as BMP co-receptors. We report here that DRAGON/RGMb, a member of the RGM family, suppressed BMP signaling in C2C12 myoblasts via a novel mechanism. All RGMs were expressed in C2C12 cells that were differentiated into myocytes and osteoblastic cells, but RGMc was not detected in immature cells. In C2C12 cells, only DRAGON suppressed ALP and Id1 promoter activities induced by BMP-4 or by constitutively activated BMP type I receptors. This inhibition by DRAGON was dependent on the secretory form of the von Willbrand factor type D domain. DRAGON even suppressed BMP signaling induced by constitutively activated Smad1. Over-expression of neogenin did not alter the inhibitory capacity of DRAGON. Taken together, these findings indicate that DRAGON may be an inhibitor of BMP signaling in C2C12 myoblasts. We also suggest that a novel molecule(s) expressed on the cell membrane may mediate the signal transduction of DRAGON in order to suppress BMP signaling in C2C12 myoblasts.

Flavonoids – Small Molecules, High Hopes

Directory of Open Access Journals (Sweden)

Sandu Mariana

2017-07-01

Full Text Available This brief review takes a look at flavonoids, a wide class of polyphenols, which are regarded as plant secondary metabolites. Their roles in plants are diverse and little understood. They can act as growth hormone modulators, phytoalexins, they offer UV protection, contribute to pollen viability and can function as signaling molecules in establishing symbiotic relationships. Flavonoids were also found to have a range of beneficial effects for the human body. Their anticancer, antioxidant, anti-inflammatory and cardioprotective activity, as well as their antibacterial, antiviral and antihelmintic properties make them promising candidates for the design of new drugs.

Characterization of Cardiac Time Intervals in Healthy Bonnet Macaques (Macaca radiata) by Using an Electronic Stethoscope

Science.gov (United States)

Kamran, Haroon; Salciccioli, Louis; Pushilin, Sergei; Kumar, Paraag; Carter, John; Kuo, John; Novotney, Carol; Lazar, Jason M

2011-01-01

Nonhuman primates are used frequently in cardiovascular research. Cardiac time intervals derived by phonocardiography have long been used to assess left ventricular function. Electronic stethoscopes are simple low-cost systems that display heart sound signals. We assessed the use of an electronic stethoscope to measure cardiac time intervals in 48 healthy bonnet macaques (age, 8 ± 5 y) based on recorded heart sounds. Technically adequate recordings were obtained from all animals and required 1.5 ± 1.3 min. The following cardiac time intervals were determined by simultaneously recording acoustic and single-lead electrocardiographic data: electromechanical activation time (QS1), electromechanical systole (QS2), the time interval between the first and second heart sounds (S1S2), and the time interval between the second and first sounds (S2S1). QS2 was correlated with heart rate, mean arterial pressure, diastolic blood pressure, and left ventricular ejection time determined by using echocardiography. S1S2 correlated with heart rate, mean arterial pressure, diastolic blood pressure, left ventricular ejection time, and age. S2S1 correlated with heart rate, mean arterial pressure, diastolic blood pressure, systolic blood pressure, and left ventricular ejection time. QS1 did not correlate with any anthropometric or echocardiographic parameter. The relation S1S2/S2S1 correlated with systolic blood pressure. On multivariate analyses, heart rate was the only independent predictor of QS2, S1S2, and S2S1. In conclusion, determination of cardiac time intervals is feasible and reproducible by using an electrical stethoscope in nonhuman primates. Heart rate is a major determinant of QS2, S1S2, and S2S1 but not QS1; regression equations for reference values for cardiac time intervals in bonnet macaques are provided. PMID:21439218

Chemical Inhibition of Kynureninase Reduces Pseudomonas aeruginosa Quorum Sensing and Virulence Factor Expression.

Science.gov (United States)

Kasper, Stephen H; Bonocora, Richard P; Wade, Joseph T; Musah, Rabi Ann; Cady, Nathaniel C

2016-04-15

The opportunistic pathogen Pseudomonas aeruginosa utilizes multiple quorum sensing (QS) pathways to coordinate an arsenal of virulence factors. We previously identified several cysteine-based compounds inspired by natural products from the plant Petiveria alliacea which are capable of antagonizing multiple QS circuits as well as reducing P. aeruginosa biofilm formation. To understand the global effects of such compounds on virulence factor production and elucidate their mechanism of action, RNA-seq transcriptomic analysis was performed on P. aeruginosa PAO1 exposed to S-phenyl-l-cysteine sulfoxide, the most potent inhibitor from the prior study. Exposure to this inhibitor down-regulated expression of several QS-regulated virulence operons (e.g., phenazine biosynthesis, type VI secretion systems). Interestingly, many genes that were differentially regulated pertain to the related metabolic pathways that yield precursors of pyochelin, tricarboxylic acid cycle intermediates, phenazines, and Pseudomonas quinolone signal (PQS). Activation of the MexT-regulon was also indicated, including the multidrug efflux pump encoded by mexEF-oprN, which has previously been shown to inhibit QS and pathogenicity. Deeper investigation of the metabolites involved in these systems revealed that S-phenyl-l-cysteine sulfoxide has structural similarity to kynurenine, a precursor of anthranilate, which is critical for P. aeruginosa virulence. By supplementing exogenous anthranilate, the QS-inhibitory effect was reversed. Finally, it was shown that S-phenyl-l-cysteine sulfoxide competitively inhibits P. aeruginosa kynureninase (KynU) activity in vitro and reduces PQS production in vivo. The kynurenine pathway has been implicated in P. aeruginosa QS and virulence factor expression; however, this is the first study to show that targeted inhibition of KynU affects P. aeruginosa gene expression and QS, suggesting a potential antivirulence strategy.

Effects of Lignosulfonate Structure on the Surface Activity and Wettability to a Hydrophobic Powder

Directory of Open Access Journals (Sweden)

Yuanyuan Ge

2014-10-01

Full Text Available The wettability of a solid material is very important in many applications, such as food, agrochemical formulations, and cosmetics. Wettability can be improved by adding surface active agents, especially biocompatible surfactants derived from biomass. In this work, the surface activity (ability to lower the surface tension of an aqueous solution and wettability toward a hydrophobic powder by a series of sodium lignosulfonates (NaLS synthesized with different degree of sulfonation (QS and weight-average molecular weights (Mw were investigated by measuring the surface tension and contact angle. The results demonstrated NaLS with a larger Mw or lower QS had higher surface activity. Conversely, the wettability of the NaLS aqueous solution toward difenoconazole powder showed a reverse trend, i.e., NaLS with a smaller Mw or higher Qs improved the wettability to difenoconazole. The surface activity and wettability was controlled by the varying densities of the NaLS molecules at the water to air interface or the solid/liquid interface, which was dependent on the molecular structure of NaLS.

In silico and experimental methods revealed highly diverse bacteria with quorum sensing and aromatics biodegradation systems--a potential broad application on bioremediation.

Science.gov (United States)

Huang, Yili; Zeng, Yanhua; Yu, Zhiliang; Zhang, Jing; Feng, Hao; Lin, Xiuchun

2013-11-01

Phylogenetic overlaps between aromatics-degrading bacteria and acyl-homoserine-lactone (AHL) or autoinducer (AI) based quorum-sensing (QS) bacteria were evident in literatures; however, the diversity of bacteria with both activities had never been finely described. In-silico searching in NCBI genome database revealed that more than 11% of investigated population harbored both aromatic ring-hydroxylating-dioxygenase (RHD) gene and AHL/AI-synthetase gene. These bacteria were distributed in 10 orders, 15 families, 42 genus and 78 species. Horizontal transfers of both genes were common among them. Using enrichment and culture dependent method, 6 Sphingomonadales and 4 Rhizobiales with phenanthrene- or pyrene-degrading ability and AHL-production were isolated from marine, wetland and soil samples. Thin-layer-chromatography and gas-chromatography-mass-spectrum revealed that these Sphingomonads produced various AHL molecules. This is the first report of highly diverse bacteria that harbored both aromatics-degrading and QS systems. QS regulation may have broad impacts on aromatics biodegradation, and would be a new angle for developing bioremediation technology. Copyright © 2013 Elsevier Ltd. All rights reserved.

A highly sensitive nanoscale pH-sensor using Au nanoparticles linked by a multifunctional Raman-active reporter molecule.

Science.gov (United States)

Lawson, Latevi S; Chan, James W; Huser, Thomas

2014-07-21

Chemical sensing on the nanoscale has been breaking new ground since the discovery of surface enhanced Raman scattering (SERS). For nanoparticles, controlled particle aggregation is necessary to achieve the largest SERS enhancements. Therefore, aggregating agents such as salts or linker molecules are used in conjunction with chemically sensitive reporters in order to develop robust environmentally sensitive SERS probes. While salt-induced colloidal nanosphere aggregates have produced robust SERS signals, their variability in aggregate size contributes significantly to poor SERS signal reproducibility, which can complicate their use in in vitro cellular studies. Such systems often also lack reproducibility in spectral measurements between different nanoparticle clusters. Preaggregation of colloids via linkers followed by surface functionalization with reporter molecules results in the linker occupying valuable SERS hotspot volume which could otherwise be utilized by additional reporter molecules. Ideally, both functionalities should be obtained from a single molecule. Here, we report the use of 3,5-dimercaptobenzoic acid, a single multifunctional molecule that creates SERS hotspots via the controlled aggregation of nanoparticles, and also reports pH values. We show that 3,5-dimercaptobenzoic acid bound to Au nanospheres results in an excellent pH nanoprobe, producing very robust, and highly reproducible SERS signals that can report pH across the entire physiological range with excellent pH resolution. To demonstrate the efficacy of our novel pH reporters, these probes were also used to image both the particle and pH distribution in the cytoplasm of human induced pluripotent stem cells (hiPSCs).

Cell surface and gene expression regulation molecules in dystrophinopathy: mdx vs. Duchenne

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RICARDO FADIC

2005-01-01

Full Text Available Duchenne muscular dystrophy (DMD is secondary to loss-of-function mutations in the dystrophin gene. The causes underlying the progression of DMD, differential muscle involvement, and the discrepancies in phenotypes among species with the same genetic defect are not understood. The mdx mouse, an animal model with dystrophin mutation, has a milder phenotype. This article reviews the available information on expression of signaling-related molecules in DMD and mdx. Extracellular matrix proteoglycans, growth factors, integrins, caveolin-3, and neuronal nitric oxide synthase expression do not show significant differences. Calcineurin is inconsistently activated in mdx, which is associated with lack of cardiomyopathy, compared to the permanent calcineurin activation in mdx/utrophin null mice that have a DMD-like cardiomyopathy. Levels of focal adhesion kinase (FAK and extracellular regulated kinases (ERKs differ among mdx and DMD. Further work is needed to identify the point of discrepancy in these signaling molecules' pathways in dystrophynopathies.

Common RNA replication signals exist among group 2 coronaviruses: evidence for in vivo recombination between animal and human coronavius molecules

International Nuclear Information System (INIS)

Wu, H.-Y.; Guy, James S.; Yoo, Dongwan; Vlasak, Reinhard; Urbach, Ena; Brian, David A.

2003-01-01

5' and 3' UTR sequences on the coronavirus genome are known to carry cis-acting elements for DI RNA replication and presumably also virus genome replication. 5' UTR-adjacent coding sequences are also thought to harbor cis-acting elements. Here we have determined the 5' UTR and adjacent 289-nt sequences, and 3' UTR sequences, for six group 2 coronaviruses and have compared them to each other and to three previously reported group 2 members. Extensive regions of highly similar UTR sequences were found but small regions of divergence were also found indicating group 2 coronaviruses could be subdivided into those that are bovine coronavirus (BCoV)-like (BCoV, human respiratory coronavirus-OC43, human enteric coronavirus, porcine hemagglutinating encephalomyelitis virus, and equine coronavirus) and those that are murine hepatitis virus (MHV)-like (A59, 2, and JHM strains of MHV, puffinosis virus, and rat sialodacryoadenitis virus). The 3' UTRs of BCoV and MHV have been previously shown to be interchangeable. Here, a reporter-containing BCoV DI RNA was shown to be replicated by all five BCoV-like helper viruses and by MHV-H2 (a human cell-adapted MHV strain), a representative of the MHV-like subgroup, demonstrating group 2 common 5' and 3' replication signaling elements. BCoV DI RNA, furthermore, acquired the leader of HCoV-OC43 by leader switching, demonstrating for the first time in vivo recombination between animal and human coronavirus molecules. These results indicate that common replication signaling elements exist among group 2 coronaviruses despite a two-cluster pattern within the group and imply there could exist a high potential for recombination among group members

Wnt secretion and signaling in Caenorhabditis elegans

NARCIS (Netherlands)

Yang, P.T.

2008-01-01

Wnt proteins are a highly conserved family of signaling molecules that play a central role during development and in adult tissue homeostasis. Wnt proteins regulate a variety of biological processes, ranging from cell proliferation and cell fate determination to cell migration, axon guidance and

The function of endocytosis in Wnt signaling.

Science.gov (United States)

Brunt, Lucy; Scholpp, Steffen

2018-03-01

Wnt growth factors regulate one of the most important signaling networks during development, tissue homeostasis and disease. Despite the biological importance of Wnt signaling, the mechanism of endocytosis during this process is ill described. Wnt molecules can act as paracrine signals, which are secreted from the producing cells and transported through neighboring tissue to activate signaling in target cells. Endocytosis of the ligand is important at several stages of action: One central function of endocytic trafficking in the Wnt pathway occurs in the source cell. Furthermore, the β-catenin-dependent Wnt ligands require endocytosis for signal activation and to regulate gene transcription in the responding cells. Alternatively, Wnt/β-catenin-independent signaling regulates endocytosis of cell adherence plaques to control cell migration. In this comparative review, we elucidate these three fundamental interconnected functions, which together regulate cellular fate and cellular behavior. Based on established hypotheses and recent findings, we develop a revised picture for the complex function of endocytosis in the Wnt signaling network.

Oxidative stress parameters induced by exposure to either cadmium or 17β-estradiol on Mytilus galloprovincialis hemocytes. The role of signaling molecules

Energy Technology Data Exchange (ETDEWEB)

Koutsogiannaki, Sophia [Laboratory of Animal Physiology, Zoology Department, School of Biology, Faculty of Science, Aristotle University of Thessaloniki, 54124 Thessaloniki (Greece); Franzellitti, Silvia [University of Bologna, Interdepartment Centre for Environmental Science Research, via S. Alberto 163, 48123 Ravenna (Italy); Fabbri, Elena [University of Bologna, Interdepartment Centre for Environmental Science Research, via S. Alberto 163, 48123 Ravenna (Italy); University of Bologna, Department of Biological, Geological, and Environmental Sciences, via Selmi 3, 40100 Bologna (Italy); Kaloyianni, Martha, E-mail: kaloyian@bio.auth.gr [Laboratory of Animal Physiology, Zoology Department, School of Biology, Faculty of Science, Aristotle University of Thessaloniki, 54124 Thessaloniki (Greece)

2014-01-15

Highlights: •Oxidative parameters in Mytilus galloprovincialis hemocytes were measured. •Comparison between cadmium and 17β-estradiol cytotoxicity is discussed. •NHE, PKC, PI3-K, NADPH oxidase, NO synthase, JNK involvement was observed. •Protective role of cAMP is suggested. •Signaling molecules studied could constitute novel biomarkers. -- Abstract: The aim of the present study was to determine and compare the possible effects of exposure to an estrogen, 17β-estradiol and to a metal, cadmium on oxidative parameters of Mytilus galloprovincialis hemocytes and to elucidate the signaling pathways that probably mediate the studied effects exerted by these two chemicals. In addition, it was of interest to investigate if the studied parameters could constitute biomarkers for aquatic pollution monitoring. Our results suggest that micromolar concentrations of either cadmium or 17β-estradiol affected the redox status of mussels by modulating oxidative parameters and antioxidant enzymes gene expression in mussel M. galloprovincialis hemocytes. In particular, our results showed that treatment of hemocytes with either 5 μM of cadmium chloride or with 25 nM of 17β-estradiol for 30 min caused significant increased ROS production; this led to oxidative damage exemplified by significant increased DNA damage, protein carbonylation and lipid peroxidation, as well as increased mRNA levels of the antioxidant enzymes catalase (CAT), superoxide dismoutase (SOD) and glutathione S-transferase (GST). Furthermore, our results suggest that either cadmium or 17β-estradiol signal is mediated either through one of the already known pathways initiated by photatidyl-inositol 3-kinase (PI3 K) and reaching Na{sup +}/H{sup +} exchanger (NHE) probably through protein kinase C (PKC) or a kinase-mediated signaling pathway that involves in most of the cases NHE, PKC, Ca{sup 2+}-dependent PKC isoforms, PI3-K, NADPH oxidase, nitric oxide (NO) synthase, c-Jun N-terminal kinase (JNK) and

Oxidative stress parameters induced by exposure to either cadmium or 17β-estradiol on Mytilus galloprovincialis hemocytes. The role of signaling molecules

International Nuclear Information System (INIS)

Koutsogiannaki, Sophia; Franzellitti, Silvia; Fabbri, Elena; Kaloyianni, Martha

2014-01-01

Highlights: •Oxidative parameters in Mytilus galloprovincialis hemocytes were measured. •Comparison between cadmium and 17β-estradiol cytotoxicity is discussed. •NHE, PKC, PI3-K, NADPH oxidase, NO synthase, JNK involvement was observed. •Protective role of cAMP is suggested. •Signaling molecules studied could constitute novel biomarkers. -- Abstract: The aim of the present study was to determine and compare the possible effects of exposure to an estrogen, 17β-estradiol and to a metal, cadmium on oxidative parameters of Mytilus galloprovincialis hemocytes and to elucidate the signaling pathways that probably mediate the studied effects exerted by these two chemicals. In addition, it was of interest to investigate if the studied parameters could constitute biomarkers for aquatic pollution monitoring. Our results suggest that micromolar concentrations of either cadmium or 17β-estradiol affected the redox status of mussels by modulating oxidative parameters and antioxidant enzymes gene expression in mussel M. galloprovincialis hemocytes. In particular, our results showed that treatment of hemocytes with either 5 μM of cadmium chloride or with 25 nM of 17β-estradiol for 30 min caused significant increased ROS production; this led to oxidative damage exemplified by significant increased DNA damage, protein carbonylation and lipid peroxidation, as well as increased mRNA levels of the antioxidant enzymes catalase (CAT), superoxide dismoutase (SOD) and glutathione S-transferase (GST). Furthermore, our results suggest that either cadmium or 17β-estradiol signal is mediated either through one of the already known pathways initiated by photatidyl-inositol 3-kinase (PI3 K) and reaching Na + /H + exchanger (NHE) probably through protein kinase C (PKC) or a kinase-mediated signaling pathway that involves in most of the cases NHE, PKC, Ca 2+ -dependent PKC isoforms, PI3-K, NADPH oxidase, nitric oxide (NO) synthase, c-Jun N-terminal kinase (JNK) and cyclic adenosine

MHC class II molecules regulate growth in human T cells

DEFF Research Database (Denmark)

Nielsen, M; Odum, Niels; Bendtzen, K

1994-01-01

MHC-class-II-positive T cells are found in tissues involved in autoimmune disorders. Stimulation of class II molecules by monoclonal antibodies (mAbs) or bacterial superantigens induces protein tyrosine phosphorylation through activation of protein tyrosine kinases in T cells, and class II signals...... lines tested. Only one of three CD4+, CD45RAhigh, ROhigh T cells responded to class II costimulation. There was no correlation between T cell responsiveness to class II and the cytokine production profile of the T cell in question. Thus, T cell lines producing interferon (IFN)-gamma but not IL-4 (TH1...... modulate several T cell responses. Here, we studied further the role of class II molecules in the regulation of T cell growth. Costimulation of class II molecules by immobilized HLA-DR mAb significantly enhanced interleukin (IL)-2-supported T cell growth of the majority of CD4+, CD45RAlow, ROhigh T cell...

Differential expression of the costimulatory molecules CD86, CD28, CD152 and PD-1 correlates with the host-parasite outcome in leprosy

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Maria de Lourdes Palermo

2012-12-01

Full Text Available Leprosy is a spectral disease exhibiting two polar sides, namely, lepromatous leprosy (LL characterised by impaired T-cell responses and tuberculoid leprosy in which T-cell responses are strong. Proper T-cell activation requires signalling through costimulatory molecules expressed by antigen presenting cells and their ligands on T-cells. We studied the influence of costimulatory molecules on the immune responses of subjects along the leprosy spectrum. The expression of the costimulatory molecules was evaluated in in vitro-stimulated peripheral blood mononuclear cells of lepromatous and tuberculoid patients and healthy exposed individuals (contacts. We show that LL patients have defective monocyte CD86 expression, which likely contributes to the impairment of the antigen presentation process and to patients anergy. Accordingly, CD86 but not CD80 blockade inhibited the lymphoproliferative response to Mycobacterium leprae. Consistent with the LL anergy, there was reduced expression of the positive signalling costimulatory molecules CD28 and CD86 on the T-cells in these patients. In contrast, tuberculoid leprosy patients displayed increased expression of the negative signalling molecules CD152 and programmed death-1 (PD-1, which represents a probable means of modulating an exacerbated immune response and avoiding immunopathology. Notably, the contacts exhibited proper CD86 and CD28 expression but not exacerbated CD152 or PD-1 expression, suggesting that they tend to develop a balanced immunity without requiring immunosuppressive costimulatory signalling.

Fluorescence single-molecule counting assays for protein quantification using epi-fluorescence microscopy with quantum dots labeling

International Nuclear Information System (INIS)

Jiang Dafeng; Liu Chunxia; Wang Lei; Jiang Wei

2010-01-01

A single-molecule counting approach for quantifying the antibody affixed to a surface using quantum dots and epi-fluorescence microscopy is presented. Modifying the glass substrates with carboxyl groups provides a hydrophilic surface that reacts with amine groups of an antibody to allow covalent immobilization of the antibody. Nonspecific adsorption of single molecules on the modified surfaces was first investigated. Then, quantum dots were employed to form complexes with surface-immobilized antibody molecules and used as fluorescent probes for single-molecule imaging. Epi-fluorescence microscopy was chosen as the tool for single-molecule fluorescence detection here. The generated fluorescence signals were taken by an electron multiplying charge-coupled device and were found to be proportional to the sample concentrations. Under optimal conditions, a linear response range of 5.0 x 10 -14 -3.0 x 10 -12 mol L -1 was obtained between the number of single molecules and sample concentration via a single-molecule counting approach.

Low energy electron-initiated ion-molecule reactions of ribose analogues

International Nuclear Information System (INIS)

Mozejko, P.

2003-01-01

Recent experiments in which plasmid DNA samples were bombarded with low energy ( 2 O, DNA bases, and sugar-phosphate backbone analogues. To this end, the cyclic molecule tetrahydrofuran, and its derivatives, provide useful models for the sugar-like molecules contained in the backbone of DNA. In addition to LEE induced dissociation by processes such as dissociative electron attachment (DEA), molecules may be damaged by ions and neutral species of non-thermal energies created by LEE in the surrounding environment. In this contribution, we investigate with electron stimulated desorption techniques, LEE damage to films of desoxy-ribose analogues in the presence of various molecular coadsorbates, that simulate changes in local molecular environment. In one type of experiments tetrahydrofuran is deposited onto multilayer O2. A desorbed signal of OH - indicates ion-molecule reactions of the type O - + C 4 H 8 O -> OH - + C 4 H 7 O, where the O - was formed initially by DEA to O 2 . Further electron stimulated desorption measurements for tetrahydrofuran and derivatives adsorbed on H 2 O, Kr, N 2 O and CH 3 OH will be presented and discussed

Weights in the balance: jasmonic acid and salicylic acid signaling in root-biotroph interactions.

Science.gov (United States)

Gutjahr, Caroline; Paszkowski, Uta

2009-07-01

Work on the interaction of aerial plant parts with pathogens has identified the signaling molecules jasmonic acid (JA) and salicylic acid (SA) as important players in induced defense of the plant against invading organisms. Much less is known about the role of JA and SA signaling in root infection. Recent progress has been made in research on plant interactions with biotrophic mutualists and parasites that exclusively associate with roots, namely arbuscular mycorrhizal and rhizobial symbioses on one hand and nematode and parasitic plant interactions on the other hand. Here, we review these recent advances relating JA and SA signaling to specific stages of root colonization and discuss how both signaling molecules contribute to a balance between compatibility and defense in mutualistic as well as parasitic biotroph-root interactions.

Chondroitin sulfates and their binding molecules in the central nervous system.

Science.gov (United States)

Djerbal, L; Lortat-Jacob, H; Kwok, Jcf

2017-06-01

Chondroitin sulfate (CS) is the most abundant glycosaminoglycan (GAG) in the central nervous system (CNS) matrix. Its sulfation and epimerization patterns give rise to different forms of CS, which enables it to interact specifically and with a significant affinity with various signalling molecules in the matrix including growth factors, receptors and guidance molecules. These interactions control numerous biological and pathological processes, during development and in adulthood. In this review, we describe the specific interactions of different families of proteins involved in various physiological and cognitive mechanisms with CSs in CNS matrix. A better understanding of these interactions could promote a development of inhibitors to treat neurodegenerative diseases.

Nitro-fatty acids in plant signaling: New key mediators of nitric oxide metabolism

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Capilla Mata-Pérez

2017-04-01

Full Text Available Recent studies in animal systems have shown that NO can interact with fatty acids to generate nitro-fatty acids (NO2-FAs. They are the product of the reaction between reactive nitrogen species and unsaturated fatty acids, and are considered novel mediators of cell signaling based mainly on a proven anti-inflammatory response. Although these signaling mediators have been described widely in animal systems, NO2-FAs have scarcely been studied in plants. Preliminary data have revealed the endogenous presence of free and protein-adducted NO2-FAs in extra-virgin olive oil (EVOO, which appear to be contributing to the cardiovascular benefits associated with the Mediterranean diet. Importantly, new findings have displayed the endogenous occurrence of nitro-linolenic acid (NO2-Ln in the model plant Arabidopsis thaliana and the modulation of NO2-Ln levels throughout this plant's development. Furthermore, a transcriptomic analysis by RNA-seq technology established a clear signaling role for this molecule, demonstrating that NO2-Ln was involved in plant-defense response against different abiotic-stress conditions, mainly by inducing the chaperone network and supporting a conserved mechanism of action in both animal and plant defense processes. Thus, NO2-Ln levels significantly rose under several abiotic-stress conditions, highlighting the strong signaling role of these molecules in the plant-protection mechanism. Finally, the potential of NO2-Ln as a NO donor has recently been described both in vitro and in vivo. Jointly, this ability gives NO2-Ln the potential to act as a signaling molecule by the direct release of NO, due to its capacity to induce different changes mediated by NO or NO-related molecules such as nitration and S-nitrosylation, or by the electrophilic capacity of these molecules through a nitroalkylation mechanism. Here, we describe the current state of the art regarding the advances performed in the field of NO2-FAs in plants and their

Meat and Livestock Association Plenary Lecture 2005. Oocyte signalling molecules and their effects on reproduction in ruminants.

Science.gov (United States)

McNatty, Kenneth P; Lawrence, Stephen; Groome, Nigel P; Meerasahib, Mohammed F; Hudson, Norma L; Whiting, Lynda; Heath, Derek A; Juengel, Jennifer L

2006-01-01

Sheep (Ovis aries) are a highly diverse species, with more than 900 different breeds that vary significantly in their physiological characteristics, including ovulation rate and fecundity. From examination of inherited patterns of ovulation rate, several breeds have been identified with point mutations in two growth factor genes that are expressed in oocytes. Currently, five different point mutations have been identified in the BMP15 (GDF9b) gene and one in GDF9. Animals heterozygous for the GDF9 and/or the BMP15 mutations have higher ovulation rates than their wild-type counterparts. In contrast, those homozygous for any of the aforementioned BMP15 or GDF9 mutations are sterile owing to arrested follicular development. In bovine and ovine ovaries, GDF9 was expressed exclusively in oocytes throughout follicular growth from the primordial stage of development, whereas in sheep BMP15 was expressed exclusively in oocytes from the primary stage: no data for the ontogeny of BMP15 expression are currently available for cattle. In vitro, ovine growth differentiation factor 9 (oGDF9) has no effect on (3)H-thymidine incorporation by either bovine or ovine granulosa cells, whereas ovine bone morphogenetic protein 15 (oBMP15) has modest (1.2- to 1.6-fold; P reproduction in mammals, including rodents, humans and ruminants. Moreover, in vivo manipulation of these oocyte signalling molecules provides new opportunities for the management of the fertility of ruminants.

Ras signaling in aging and metabolic regulation.

Science.gov (United States)

Slack, Cathy

2017-12-07

Aberrant signal transduction downstream of the Ras GTPase has a well-established role in tumorigenesis. Mutations that result in hyperactivation of Ras are responsible for a third of all human cancers. Hence, small molecule inhibitors of the Ras signal transduction cascade have been under intense focus as potential cancer treatments. In both invertebrate and mammalian models, emerging evidence has also implicated components of the Ras signaling pathway in aging and metabolic regulation. Here, I review the current evidence for Ras signaling in these newly discovered roles highlighting the interactions between the Ras pathway and other longevity assurance mechanisms. Defining the role of Ras signaling in maintaining age-related health may have important implications for the development of interventions that could not only increase lifespan but also delay the onset and/or progression of age-related functional decline.

Deuterium-labelled N-acyl-l-homoserine lactones (AHLs) - inter-kingdom signalling molecules - synthesis, structural studies, and interactions with model lipid membranes

Energy Technology Data Exchange (ETDEWEB)

Jakubczyk, Dorota [Institute of Organic Chemistry, Karlsruhe Institute of Technology, Karlsruhe (Germany); Institute of Functional Interfaces, Karlsruhe Institute of Technology, Eggenstein-Leopoldshafen (Germany); Barth, Christoph; Anastassacos, Frances; Koelsch, Patrick; Schepers, Ute [Institute of Toxicology and Genetics, Karlsruhe Institute of Technology, Eggenstein-Leopoldshafen (Germany); Kubas, Adam; Fink, Karin [Institute of Nanotechnology, Karlsruhe Institute of Technology, Eggenstein-Leopoldshafen (Germany); Brenner-Weiss, Gerald [Institute of Functional Interfaces, Karlsruhe Institute of Technology, Eggenstein-Leopoldshafen (Germany); Braese, Stefan [Institute of Organic Chemistry, Karlsruhe Institute of Technology, Karlsruhe (Germany)

2012-04-15

N-Acyl-l-homoserine lactones (AHLs) are synthesized by Gram-negative bacteria. These quorum-sensing molecules play an important role in the context of bacterial infection and biofilm formation. They also allow communication between microorganisms and eukaryotic cells (inter-kingdom signalling). However, very little is known about the entire mechanism of those interactions. Precise structural studies are required to analyse the different AHL isomers as only one form is biologically most active. Theoretical studies combined with experimental infrared and Raman spectroscopic data are therefore undertaken to characterise the obtained compounds. To mimic interactions between AHL and cell membranes, we studied the insertion of AHL in supported lipid bilayers, using vibrational sum-frequency-generation spectroscopy. Deuterium-labelled AHLs were thus synthesized. Starting from readily available deuterated fatty acids, a two-step procedure towards deuterated N-acyl-l-homoserine lactones with varying chain lengths is described. This included the acylation of Meldrum's acid followed by amidation. Additionally, the detailed analytical evaluation of the products is presented herein. (orig.)

Strategy for signaling molecule detection by using an integrated microfluidic device coupled with mass spectrometry to study cell-to-cell communication.

Science.gov (United States)

Mao, Sifeng; Zhang, Jie; Li, Haifang; Lin, Jin-Ming

2013-01-15

Cell-to-cell communication is a very important physiological behavior in life entity, and most of human behaviors are related to it. Although cell-to-cell communications are attracting much attention and financial support, rare methods have been successfully developed for in vitro cell-to-cell communication study. In this work, we developed a novel method for cell-to-cell communication study on an integrated microdevice, and signaling molecule and metabolites were online-detected by an electrospray ionization-quadrupole-time-of-flight-mass spectrometer (ESI-Q-TOF-MS) after on-chip solid-phase extraction. Moreover, we presented a "Surface Tension Plug" on a microchip to control cell-to-cell communication. The microdevice consists of three functional sections: cell coculture channel, targets pretreatment, and targets detection sections. To verify the feasibility of cell-to-cell communications on the integrated microdevice, we studied the communication between the 293 and the L-02 cells. Epinephrine and glucose were successfully detected using an ESI-Q-TOF-MS with short analysis time (communication study.

Gastrin-releasing peptide induces monocyte adhesion to vascular endothelium by upregulating endothelial adhesion molecules

International Nuclear Information System (INIS)

Kim, Mi-Kyoung; Park, Hyun-Joo; Kim, Yeon; Kim, Hyung Joon; Bae, Soo-Kyung; Bae, Moon-Kyoung

2017-01-01

Gastrin-releasing peptide (GRP) is a neuropeptide that plays roles in various pathophysiological conditions including inflammatory diseases in peripheral tissues; however, little is known about whether GRP can directly regulate endothelial inflammatory processes. In this study, we showed that GRP promotes the adhesion of leukocytes to human umbilical vein endothelial cells (HUVECs) and the aortic endothelium. GRP increased the expression of intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) by activating nuclear factor-κB (NF-κB) in endothelial cells. In addition, GRP activated extracellular signal-regulated kinase 1/2 (ERK1/2), p38MAPK, and AKT, and the inhibition of these signaling pathways significantly reduced GRP-induced monocyte adhesion to the endothelium. Overall, our results suggested that GRP may cause endothelial dysfunction, which could be of particular relevance in the development of vascular inflammatory disorders. - Highlights: • GRP induces adhesion of monocytes to vascular endothelium. • GRP increases the expression of endothelial adhesion molecules through the activation of NF-κB. • ERK1/2, p38MAPK, and Akt pathways are involved in the GRP-induced leukocyte adhesiveness to endothelium.

Sweet Taste Receptor Signaling Network: Possible Implication for Cognitive Functioning

Directory of Open Access Journals (Sweden)

Menizibeya O. Welcome

2015-01-01

Full Text Available Sweet taste receptors are transmembrane protein network specialized in the transmission of information from special “sweet” molecules into the intracellular domain. These receptors can sense the taste of a range of molecules and transmit the information downstream to several acceptors, modulate cell specific functions and metabolism, and mediate cell-to-cell coupling through paracrine mechanism. Recent reports indicate that sweet taste receptors are widely distributed in the body and serves specific function relative to their localization. Due to their pleiotropic signaling properties and multisubstrate ligand affinity, sweet taste receptors are able to cooperatively bind multiple substances and mediate signaling by other receptors. Based on increasing evidence about the role of these receptors in the initiation and control of absorption and metabolism, and the pivotal role of metabolic (glucose regulation in the central nervous system functioning, we propose a possible implication of sweet taste receptor signaling in modulating cognitive functioning.

Impact of exogenous lipase supplementation on growth, intestinal function, mucosal immune and physical barrier, and related signaling molecules mRNA expression of young grass carp (Ctenopharyngodon idella).

Science.gov (United States)

Liu, Sen; Feng, Lin; Jiang, Wei-Dan; Liu, Yang; Jiang, Jun; Wu, Pei; Zeng, Yun-Yun; Xu, Shu-De; Kuang, Sheng-Yao; Tang, Ling; Tang, Wu-Neng; Zhang, Yong-An; Zhou, Xiao-Qiu

2016-08-01

This study investigated the effects of exogenous lipase supplementation on the growth performance, intestinal growth and function, immune response and physical barrier function, and related signaling molecules mRNA expression of young grass carp (Ctenopharyngodon idella). A total of 450 grass carp (255.02 ± 0.34 g) were fed five diets for 60 days. There were 5 dietary treatments that included a normal protein and lipid diet containing 30% crude protein (CP) with 5% ether extract (EE), and the low-protein and high-lipid diets (28% CP, 6% EE) supplemented with graded levels of exogenous lipase supplementation activity at 0, 1193, 2560 and 3730 U/kg diet. The results indicated that compared with a normal protein and lipid diet (30% CP, 5% EE), a low-protein and high-lipid diet (28% CP, 6% EE) (un-supplemented lipase) improved lysozyme activities and complement component 3 contents in the distal intestine (DI), interleukin 10 mRNA expression in the proximal intestine (PI), and glutathione S-transferases activity and glutathione content in the intestine of young grass carp. In addition, in low-protein and high-lipid diets, optimal exogenous lipase supplementation significantly increased acid phosphatase (ACP) activities and complement component 3 (C3) contents (P exogenous lipase supplementation significantly decreased reactive oxygen species (ROS), malondialdehyde (MDA) and protein carbonyl (PC) contents (P exogenous lipase supplementation significantly elevated the mRNA levels of tight junction proteins (Occludin, zonula occludens 1, Claudin b, Claudin c and Claudin 3) (P exogenous lipase supplementation improved growth, intestinal growth and function, intestinal immunity, physical barrier, and regulated the mRNA expression of related signal molecules of fish. The optimal level of exogenous lipase supplementation in young grass carp (255-771 g) was estimated to be 1193 U kg(-1) diet. Copyright © 2016. Published by Elsevier Ltd.

Chemical intervention in plant sugar signalling increases yield and resilience

Science.gov (United States)

Griffiths, Cara A.; Sagar, Ram; Geng, Yiqun; Primavesi, Lucia F.; Patel, Mitul K.; Passarelli, Melissa K.; Gilmore, Ian S.; Steven, Rory T.; Bunch, Josephine; Paul, Matthew J.; Davis, Benjamin G.

2016-12-01

The pressing global issue of food insecurity due to population growth, diminishing land and variable climate can only be addressed in agriculture by improving both maximum crop yield potential and resilience. Genetic modification is one potential solution, but has yet to achieve worldwide acceptance, particularly for crops such as wheat. Trehalose-6-phosphate (T6P), a central sugar signal in plants, regulates sucrose use and allocation, underpinning crop growth and development. Here we show that application of a chemical intervention strategy directly modulates T6P levels in planta. Plant-permeable analogues of T6P were designed and constructed based on a ‘signalling-precursor’ concept for permeability, ready uptake and sunlight-triggered release of T6P in planta. We show that chemical intervention in a potent sugar signal increases grain yield, whereas application to vegetative tissue improves recovery and resurrection from drought. This technology offers a means to combine increases in yield with crop stress resilience. Given the generality of the T6P pathway in plants and other small-molecule signals in biology, these studies suggest that suitable synthetic exogenous small-molecule signal precursors can be used to directly enhance plant performance and perhaps other organism function.

AI-2 does not function as a quorum sensing molecule in Campylobacter jejuni during exponential growth in vitro

NARCIS (Netherlands)

Holmes, K.; Tavender, T.J.; Winzer, K.; Wells, J.; Hardie, K.

2009-01-01

Background - Campylobacter jejuni contains a homologue of the luxS gene shown to be responsible for the production of the signalling molecule autoinducer-2 (AI-2) in Vibrio harveyi and Vibrio cholerae. The aim of this study was to determine whether AI-2 acted as a diffusible quorum sensing signal

Conformational analysis of g protein-coupled receptor signaling by hydrogen/deuterium exchange mass spectrometry.

Science.gov (United States)

Li, Sheng; Lee, Su Youn; Chung, Ka Young

2015-01-01

Conformational change and protein-protein interactions are two major mechanisms of membrane protein signal transduction, including G protein-coupled receptors (GPCRs). Upon agonist binding, GPCRs change conformation, resulting in interaction with downstream signaling molecules such as G proteins. To understand the precise signaling mechanism, studies have investigated the structural mechanism of GPCR signaling using X-ray crystallography, nuclear magnetic resonance (NMR), or electron paramagnetic resonance. In addition to these techniques, hydrogen/deuterium exchange mass spectrometry (HDX-MS) has recently been used in GPCR studies. HDX-MS measures the rate at which peptide amide hydrogens exchange with deuterium in the solvent. Exposed or flexible regions have higher exchange rates and excluded or ordered regions have lower exchange rates. Therefore, HDX-MS is a useful tool for studying protein-protein interfaces and conformational changes after protein activation or protein-protein interactions. Although HDX-MS does not give high-resolution structures, it analyzes protein conformations that are difficult to study with X-ray crystallography or NMR. Furthermore, conformational information from HDX-MS can help in the crystallization of X-ray crystallography by suggesting highly flexible regions. Interactions between GPCRs and downstream signaling molecules are not easily analyzed by X-ray crystallography or NMR because of the large size of the GPCR-signaling molecule complexes, hydrophobicity, and flexibility of GPCRs. HDX-MS could be useful for analyzing the conformational mechanism of GPCR signaling. In this chapter, we discuss details of HDX-MS for analyzing GPCRs using the β2AR-G protein complex as a model system. © 2015 Elsevier Inc. All rights reserved.

Acidic properties of SSZ-33 and SSZ-35 novel zeolites: a complex infrared and MAS NMR study

Czech Academy of Sciences Publication Activity Database

Gil, B.; Zones, S. I.; Hwang, S.-J.; Voláková, Martina; Čejka, Jiří

2008-01-01

Roč. 112, č. 8 (2008), s. 2997-3007 ISSN 1932-7447 R&D Projects: GA ČR GA104/07/0383; GA AV ČR 1QS400400560 Institutional research plan: CEZ:AV0Z40400503 Keywords : nuclear magnetic resonance * adsorbed probe molecules * angle- spinning NMR Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 3.396, year: 2008

Mixed Signals: Co-Stimulation in Invariant Natural Killer T Cell-Mediated Cancer Immunotherapy

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Susannah C. Shissler

2017-11-01

Full Text Available Invariant natural killer T (iNKT cells are an integral component of the immune system and play an important role in antitumor immunity. Upon activation, iNKT cells can directly kill malignant cells as well as rapidly produce cytokines that stimulate other immune cells, making them a front line defense against tumorigenesis. Unfortunately, iNKT cell number and activity are reduced in multiple cancer types. This anergy is often associated with upregulation of co-inhibitory markers such as programmed death-1. Similar to conventional T cells, iNKT cells are influenced by the conditions of their activation. Conventional T cells receive signals through the following three types of receptors: (1 T cell receptor (TCR, (2 co-stimulation molecules, and (3 cytokine receptors. Unlike conventional T cells, which recognize peptide antigen presented by MHC class I or II, the TCRs of iNKT cells recognize lipid antigen in the context of the antigen presentation molecule CD1d (Signal 1. Co-stimulatory molecules can positively and negatively influence iNKT cell activation and function and skew the immune response (Signal 2. This study will review the background of iNKT cells and their co-stimulatory requirements for general function and in antitumor immunity. We will explore the impact of monoclonal antibody administration for both blocking inhibitory pathways and engaging stimulatory pathways on iNKT cell-mediated antitumor immunity. This review will highlight the incorporation of co-stimulatory molecules in antitumor dendritic cell vaccine strategies. The use of co-stimulatory intracellular signaling domains in chimeric antigen receptor-iNKT therapy will be assessed. Finally, we will explore the influence of innate-like receptors and modification of immunosuppressive cytokines (Signal 3 on cancer immunotherapy.

Enhancement of Chiroptical Signals by Circular Differential Mie Scattering of Nanoparticles.

Science.gov (United States)

Yoo, SeokJae; Park, Q-Han

2015-09-25

We enhance the weak optical signals of small chiral molecules via circular differential Mie scattering (CDMS) of nanoparticles immersed in them. CDMS is the preferential Mie scattering of left- and right-handed circularly polarized light by nanoparticles whose sizes are about the same as the wavelength of light. Solving the Mie scattering theory for chiral media, we find that the CDMS signal of the particle is linearly proportional to the chirality parameter κ of the molecules. This linear amplitude enhancement by CDMS of the particle holds, even for large particles, which have a retardation effect. We also demonstrate that the CDMS of a nanoparticle is sensitive to changes of molecular concentration, and that the nanoparticle can be utilized as a chiroptical biosensor detecting the concentration of analyte. We expect that the enhancement of molecular chiroptical signals by CDMS will pave the way for novel chiroptical spectroscopy using nanostructures.

Quorum sensing signal profile of Acinetobacter strains from nosocomial and environmental sources Perfil de sensores de quórum en cepas nosocomiales y ambientales de Acinetobacter

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R. H. González

2009-06-01

Full Text Available A set of 43 strains corresponding to 20 classified and unclassified genomic Acinetobacter species was analyzed for the production of typical N-acyl homoserine lactone quorum sensing molecules in culture broths. A large percentage of the strains (74% displayed quorum sensing signals that could be separated into three statistically significantly different chromatographic groups (p Rf2 > Rf1. None of the three signals could be specifically assigned to a particular species in the genus; furthermore, no distinction could be made between the quorum sensing signals secreted by typical opportunistic strains of the A. calcoaceticus-A. baumannii complex, isolated from patients, with respect to the other species of the genus, except for the Rf1 signal which was present in all the QS positive strains belonging to this complex and DNA group 13 TU. In conclusion, quorum sensors in Acinetobacter are not homogenously distributed among species and one of them is present in most of the A. calcoaceticus-baumannii complex.Se analizó la producción de moléculas típicas de N-acil homoserina lactona con actividad de quorum sensing en cultivos líquidos de un grupo de 43 cepas correspondientes a 20 especies genómicas clasificadas y no clasificadas de Acinetobacter. Un porcentaje alto de las cepas (74% mostraron señales de quorum sensing que pudieron ser separadas en tres grupos cromatográficos significativamente diferentes entre sí (p Rf2 > Rf1. Ninguna de las tres señales pudo ser asignada a una especie en particular dentro del género; es más, no se encontró diferencia entre las señales producidas por las cepas típicamente oportunistas (complejo A. calcoaceticus-A. baumannii aisladas de pacientes respecto de las producidas por otras cepas del mismo género, excepto para el caso de Rf1, que se encontró presente en todos los aislamientos quorum sensing positivos del mencionado complejo y en las cepas del grupo de DNA 13TU. En conclusión, los sensores de

Antimicrobial and anti-Quorum Sensing activities of selected medicinal plants of Ethiopia: Implication for development of potent antimicrobial agents.

Science.gov (United States)

Bacha, Ketema; Tariku, Yinebeb; Gebreyesus, Fisseha; Zerihun, Shibru; Mohammed, Ali; Weiland-Bräuer, Nancy; Schmitz, Ruth A; Mulat, Mulugeta

2016-07-11

Traditional medicinal plants have been used as an alternative medicine in many parts of the world, including Ethiopia. There are many documented scientific reports on antimicrobial activities of the same. To our knowledge, however, there is no report on the anti-Quorum Sensing (Quorum Quenching, QQ) potential of traditional Ethiopian medicinal plants. As many of the opportunistic pathogenic bacteria depend on Quorum Sensing (QS) systems to coordinate their virulence expression, interference with QS could be a novel approach to control bacterial infections. Thus, the aim of this study was to evaluate selected medicinal plants from Ethiopia for their antimicrobial activities against bacterial and fungal pathogens; and to assess the interference of these plant extracts with QS of bacteria. Antimicrobial activities of plant extracts (oil, resins and crude extracts) were evaluated following standard agar diffusion technique. The minimum inhibitory concentrations (MIC) of potent extracts were determined using 96 well micro-titer plates and optical densities were measured using an ELISA Microplate reader. Interference with Quorum Sensing activities of extracts was determined using the recently established E. coli based reporter strain AI1-QQ.1 and signaling molecule N-(ß-ketocaproyl)-L-homoserine lactone (3-oxo-C6-HSL). Petroleum ether extract of seed of Nigella sativa exhibited the highest activity against both the laboratory isolated Bacillus cereus [inhibition zone (IZ), 44 ± 0.31 mm] and B. cereus ATCC 10987 (IZ, 40 ± 2.33 mm). Similarly, oil extract from mature ripe fruit husk of Aframomum corrorima and mature unripe fruit of A. corrorima revealed promising activities against Candida albicans ATCC 90028 (IZ, 35 ± 1.52 mm) and Staphylococcus aureus DSM 346 (IZ, 25 ± 1.32 mm), respectively. Antimicrobial activities of oil extract from husk of A. corrorima and petroleum ether extract of seed of N. sativa were significantly higher than that of

Inhibitory Effect of Curcumol on Jak2-STAT Signal Pathway Molecules of Fibroblast-Like Synoviocytes in Patients with Rheumatoid Arthritis

Directory of Open Access Journals (Sweden)

Heng Wang

2012-01-01

Full Text Available Hyperplasia of synovial membrane in rheumatoid arthritis (RA is a critical pathological foundation for inducing articular injury. The janus kinase and signal transducer and activator of transcription (Jak-STAT pathway plays a critical role in synovial membrane proliferation induced by platelet-derived growth factor (PDGF. To explore the anti-cell proliferation mechanism of curcumol, a pure monomer extracted from Chinese medical plant zedoary rhizome, the changes of Jak2-STAT1/3 signal pathway-related molecules in synoviocytes were observed in vitro. In this study, the fibroblast-like synoviocytes (FLS in patients with RA were collected and cultured. The following parameters were measured: cell proliferation (WST-1 assay, cell cycles (fluorescence-activated cell sorting, FACS, STAT1 and STAT3 activities (electrophoretic mobility shift assay, EMSA, and the protein expressions of phosphorylated Jak2, STAT1, and STAT3 (Western blot. It was shown that curcumol could inhibit the RA-FLS proliferation and DNA synthesis induced by PDGF-BB in a dose-dependent manner in vitro. The transcription factors activities of STAT1 and STAT3 were obviously elevated after PDGF-BB stimulation (P<0.05. Super-shift experiments identified the STAT1 or STAT3 proteins in the complex. Furthermore, the different concentration curcumol could downregulate the DNA binding activities of STAT1 and STAT3 (P<0.05 and inhibit the phosphorylation of Jak2 while it had no effect on the protein expressions of STAT1 and STAT3. Positive correlations were found between changes of cell proliferation and DNA-binding activities of STAT1 and STAT3, respectively (P<0.01. In conclusion, curcumol might suppress the FLS proliferation and DNA synthesis induced by PDGF-BB through attenuating Jak2 phosphorylation, downregulating STAT1 and STAT3 DNA-binding activities, which could provide theoretical foundation for clinical treatment of RA.

Tissue Architecture and Microenvironment Sustain Hormone Signaling | Center for Cancer Research

Science.gov (United States)

Cells interact with their environments in part through protein receptors embedded in the cell membrane. Activation of a receptor by external signaling molecules sets off a complex chain of events within the cell that can result in alterations in protein structure and function and/or changes in gene expression. Proper integration of these signals is crucial for normal cell

The imidazopyridine derivative JK184 reveals dual roles for microtubules in Hedgehog signaling.

Science.gov (United States)

Cupido, Tommaso; Rack, Paul G; Firestone, Ari J; Hyman, Joel M; Han, Kyuho; Sinha, Surajit; Ocasio, Cory A; Chen, James K

2009-01-01

Eradicating hedgehogs: The title molecule has been previously identified as a potent inhibitor of the Hedgehog signaling pathway, which gives embryonic cells information needed to develop properly. This molecule is shown to modulate Hedgehog target gene expression by depolymerizing microtubules, thus revealing dual roles of the cytoskeleton in pathway regulation (see figure).

Signalling in malaria parasites – The MALSIG consortium#

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Doerig C.

2009-09-01

Full Text Available Depending on their developmental stage in the life cycle, malaria parasites develop within or outside host cells, and in extremely diverse contexts such as the vertebrate liver and blood circulation, or the insect midgut and hemocoel. Cellular and molecular mechanisms enabling the parasite to sense and respond to the intra- and the extra-cellular environments are therefore key elements for the proliferation and transmission of Plasmodium, and therefore are, from a public health perspective, strategic targets in the fight against this deadly disease. The MALSIG consortium, which was initiated in February 2009, was designed with the primary objective to integrate research ongoing in Europe and India on i the properties of Plasmodium signalling molecules, and ii developmental processes occurring at various points of the parasite life cycle. On one hand, functional studies of individual genes and their products in Plasmodium falciparum (and in the technically more manageable rodent model Plasmodium berghei are providing information on parasite protein kinases and phosphatases, and of the molecules governing cyclic nucleotide metabolism and calcium signalling. On the other hand, cellular and molecular studies are elucidating key steps of parasite development such as merozoite invasion and egress in blood and liver parasite stages, control of DNA replication in asexual and sexual development, membrane dynamics and trafficking, production of gametocytes in the vertebrate host and further parasite development in the mosquito. This article, which synthetically reviews such signalling molecules and cellular processes, aims to provide a glimpse of the global frame in which the activities of the MALSIG consortium will develop over the next three years.

FASEB summer research conference on signal transduction in plants. Final report, June 16, 1996--June 21, 1996

Energy Technology Data Exchange (ETDEWEB)

Lomax, T.L.; Quatrano, R.S.

1996-12-31

This is the program from the second FASEB conference on Signal Transduction in Plants. Topic areas included the following: environmental signaling; perception and transduction of light signals; signaling in plant microbe interactions; signaling in plant pathogen interactions; cell, cell communication; cytoskeleton, plasma membrane, and cellwall continuum; signaling molecules in plant growth and development I and II. A list of participants is included.

Fructose and glucose signaling in Arabidopsis thaliana

NARCIS (Netherlands)

Wind, J.J.

2012-01-01

All life on earth depends on photosynthesis, a process by which energy from sunlight is used to convert water and carbon dioxide into sugars and oxygen. In plants, sugars are used as building blocks for growth, energy and transport. Sugars have an important role as signaling molecule as well, and

Temporal protein expression pattern in intracellular signalling ...

Indian Academy of Sciences (India)

2015-09-28

Sep 28, 2015 ... targets for the treatment of various T-cells, immune-related diseases. We hope ... signifies the alternative routes of signal propagation. The molecules kept in ...... growth factor, mitogens for vascular cells and fibroblasts: dif- ferential ..... tumor necrosis factor contributes to CD8(+) T cell survival in the transition ...

Expression of costimulatory molecules in the bovine corpus luteum

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Pate Joy L

2007-01-01

Full Text Available Abstract Background Bovine luteal parenchymal cells express class II major histocompatibility complex (MHC molecules and stimulate class II MHC-dependent activation of T cells in vitro. The ability of a class II MHC-expressing cell type to elicit a response from T cells in vivo is also dependent on expression of costimulatory molecules by the antigen presenting cell and delivery of a costimulatory signal to the T cell. Whether bovine luteal parenchymal cells express costimulatory molecules and can deliver the costimulatory signal is currently unknown. Methods Bovine luteal tissue was collected during the early (day 5; day of estrus = day 0, mid (day 11–12, or late (day 18 luteal phase of the estrous cycle, and at 0, 0.5, 1, 4, 12 or 24 hours following administration of PGF2alpha to cows on day 10 of the estrous cycle. Northern analysis was used to measure CD80 or CD86 mRNA concentrations in luteal tissue samples. Mixed luteal parenchymal cell cultures and purified luteal endothelial cell cultures were prepared, and real-time RT-PCR was used to examine the presence of CD80 and CD86 mRNA in each culture type. Monoclonal antibodies to CD80 and CD86 were added to a mixed luteal parenchymal cell-T cell co-culture in vitro T cell proliferation assay to assess the functional significance of costimulatory molecules on activation of T lymphocytes by luteal parenchymal cells. Results Northern analysis revealed CD80 and CD86 mRNAs in luteal tissue, with greatest steady-state concentrations at midcycle. CD80 and CD86 mRNAs were detected in mixed luteal parenchymal cell cultures, but only slight amounts of CD80 (and not CD86 mRNA were detected in cultures of luteal endothelial cells. Luteinizing hormone, PGF2alpha and TNF-alpha were without effect on concentrations of CD80 or CD86 mRNA in mixed luteal parenchymal cells cultures. Anti-CD80 or anti-CD86 monoclonal antibodies inhibited T cell proliferation in the in vitro T cell proliferation assay

Single-Molecule Light-Sheet Imaging of Suspended T Cells.

Science.gov (United States)

Ponjavic, Aleks; McColl, James; Carr, Alexander R; Santos, Ana Mafalda; Kulenkampff, Klara; Lippert, Anna; Davis, Simon J; Klenerman, David; Lee, Steven F

2018-05-08

Adaptive immune responses are initiated by triggering of the T cell receptor. Single-molecule imaging based on total internal reflection fluorescence microscopy at coverslip/basal cell interfaces is commonly used to study this process. These experiments have suggested, unexpectedly, that the diffusional behavior and organization of signaling proteins and receptors may be constrained before activation. However, it is unclear to what extent the molecular behavior and cell state is affected by the imaging conditions, i.e., by the presence of a supporting surface. In this study, we implemented single-molecule light-sheet microscopy, which enables single receptors to be directly visualized at any plane in a cell to study protein dynamics and organization in live, resting T cells. The light sheet enabled the acquisition of high-quality single-molecule fluorescence images that were comparable to those of total internal reflection fluorescence microscopy. By comparing the apical and basal surfaces of surface-contacting T cells using single-molecule light-sheet microscopy, we found that most coated-glass surfaces and supported lipid bilayers profoundly affected the diffusion of membrane proteins (T cell receptor and CD45) and that all the surfaces induced calcium influx to various degrees. Our results suggest that, when studying resting T cells, surfaces are best avoided, which we achieve here by suspending cells in agarose. Copyright © 2018. Published by Elsevier Inc.

Altered expression of signalling lymphocyte activation molecule receptors in T-cells from lupus nephritis patients-a potential biomarker of disease activity.

Science.gov (United States)

Stratigou, Victoria; Doyle, Anne F; Carlucci, Francesco; Stephens, Lauren; Foschi, Valentina; Castelli, Marco; McKenna, Nicola; Cook, H Terence; Lightstone, Liz; Cairns, Thomas D; Pickering, Matthew C; Botto, Marina

2017-07-01

The aim was to investigate whether the signalling lymphocyte activation molecule (SLAM) signalling pathways contribute to LN and whether SLAM receptors could be valuable biomarkers of disease activity. Peripheral blood mononuclear cells from 30National Research Ethics Service SLE patients with biopsy-proven LN were analysed by flow cytometry. Clinical measures of disease activity were assessed. The expression of the SLAM family receptors on T-cell subpopulations [CD4, CD8 and double negative (DN) T cells] was measured and compared between lupus patients with active renal disease and those in remission. The frequency of CD8 T cells expressing SLAMF3, SLAMF5 and SLAMF7 was significantly lower in LN patients who were in remission. In contrast, these subsets were similar in patients with active renal disease and in healthy individuals. Patients with active nephritis had an increased percentage of circulating monocytes, consistent with a potential role played by these cells in glomerular inflammation. Changes in the frequency of DN T cells positive for SLAMF2, SLAMF4 and SLAMF7 were observed in lupus patients irrespective of the disease activity. We detected alterations in the cellular expression of the SLAM family receptors, but these changes were less obvious and did not reveal any specific pattern. The percentage of DN T cells expressing SLAMF6 could predict the clinical response to B-cell depletion in patients with LN. Our study demonstrates altered expression of the SLAM family receptors in SLE T lymphocytes. This is consistent with the importance of the SLAM-associated pathways in lupus pathogenesis. © The Author 2017. Published by Oxford University Press on behalf of the British Society for Rheumatology.

CD54/intercellular adhesion molecule 1 and major histocompatibility complex II signaling induces B cells to express interleukin 2 receptors and complements help provided through CD40 ligation

DEFF Research Database (Denmark)

Poudrier, J; Owens, T

1994-01-01

We have examined signaling roles for CD54 intercellular adhesion molecule 1 and major histocompatibility complex (MHC) II as contact ligands during T help for B cell activation. We used a T helper 1 (Th1)-dependent helper system that was previously shown to be contact as well as interleukin 2 (IL-2......) dependent to demonstrate the relative roles of CD54, MHC II, and CD40 signaling in the events leading to the induction of B cell proliferation and responsiveness to IL-2. Paraformaldehyde-fixed activated Th1-induced expression of IL-2R alpha, IL-2R beta, and B7, and upregulated MHC II and CD54 on B cells...... resulted in the upregulated expression of MHC II and of CD54 and B7, respectively, analogous to the effect of fixed activated Th1 cells. B7 expression was further enhanced by co-cross-linking CD54 and MHC II. Cross-linking of CD40 achieved comparable effects. Strikingly, cross-linking ligation of CD54...

Single-molecule fluorescence microscopy review: shedding new light on old problems.

Science.gov (United States)

Shashkova, Sviatlana; Leake, Mark C

2017-08-31

Fluorescence microscopy is an invaluable tool in the biosciences, a genuine workhorse technique offering exceptional contrast in conjunction with high specificity of labelling with relatively minimal perturbation to biological samples compared with many competing biophysical techniques. Improvements in detector and dye technologies coupled to advances in image analysis methods have fuelled recent development towards single-molecule fluorescence microscopy, which can utilize light microscopy tools to enable the faithful detection and analysis of single fluorescent molecules used as reporter tags in biological samples. For example, the discovery of GFP, initiating the so-called 'green revolution', has pushed experimental tools in the biosciences to a completely new level of functional imaging of living samples, culminating in single fluorescent protein molecule detection. Today, fluorescence microscopy is an indispensable tool in single-molecule investigations, providing a high signal-to-noise ratio for visualization while still retaining the key features in the physiological context of native biological systems. In this review, we discuss some of the recent discoveries in the life sciences which have been enabled using single-molecule fluorescence microscopy, paying particular attention to the so-called 'super-resolution' fluorescence microscopy techniques in live cells, which are at the cutting-edge of these methods. In particular, how these tools can reveal new insights into long-standing puzzles in biology: old problems, which have been impossible to tackle using other more traditional tools until the emergence of new single-molecule fluorescence microscopy techniques. © 2017 The Author(s).

[Effect of Biejiajian Pills on Wnt signal pathway molecules β-catenin and GSK-3β and the target genes CD44v6 and VEGF in hepatocellular carcinoma cells].

Science.gov (United States)

Sun, Haitao; He, Songqi; Wen, Bin; Jia, Wenyan; Fan, Eryan; Zheng, Yan

2014-10-01

To investigate the effect of Biejiajian Pills on the expressions of the signal molecules and target genes of Wnt signal pathway in HepG2 cells and explore the mechanisms by which Biejiajian pills suppress the invasiveness of hepatocellular carcinoma. HepG2 cells were cultured for 48 h in the presence of serum collected from rats fed with Biejiajian Pills. The expressions of β-catenin, GSK-3β and P-GSK-3β in the cultured cells were assessed by Western blotting and the expressions of CD44v6 and VEGF were detected using immunohistochemistry. HepG2 cells cultured with the serum of rats fed with Biejiajian Pills showed lowered expressions of β-catenin protein both in the cytoplasm and the nuclei with also inhibition of phosphorylation of GSK-3β and reduced expression of CD44v6 and VEGF. Biejiajian Pills can significantly reduce the expression of β-catenin by decreasing the phosphorylation of GSK-3β and blocking the Wnt/β-catenin signaling pathway to cause down-regulation of the target genes CD44v6 and VEGF, which may be one of the molecular mechanisms by which Biejiajian Pills suppress the proliferation and invasiveness of hepatocellular carcinoma.

Post-transcriptional bursting in genes regulated by small RNA molecules

Science.gov (United States)

Rodrigo, Guillermo

2018-03-01

Gene expression programs in living cells are highly dynamic due to spatiotemporal molecular signaling and inherent biochemical stochasticity. Here we study a mechanism based on molecule-to-molecule variability at the RNA level for the generation of bursts of protein production, which can lead to heterogeneity in a cell population. We develop a mathematical framework to show numerically and analytically that genes regulated post transcriptionally by small RNA molecules can exhibit such bursts due to different states of translation activity (on or off), mostly revealed in a regime of few molecules. We exploit this framework to compare transcriptional and post-transcriptional bursting and also to illustrate how to tune the resulting protein distribution with additional post-transcriptional regulations. Moreover, because RNA-RNA interactions are predictable with an energy model, we define the kinetic constants of on-off switching as functions of the two characteristic free-energy differences of the system, activation and formation, with a nonequilibrium scheme. Overall, post-transcriptional bursting represents a distinctive principle linking gene regulation to gene expression noise, which highlights the importance of the RNA layer beyond the simple information transfer paradigm and significantly contributes to the understanding of the intracellular processes from a first-principles perspective.

Pattern-recognition receptors: signaling pathways and dysregulation in canine chronic enteropathies-brief review.

Science.gov (United States)

Heilmann, Romy M; Allenspach, Karin

2017-11-01

Pattern-recognition receptors (PRRs) are expressed by innate immune cells and recognize pathogen-associated molecular patterns (PAMPs) as well as endogenous damage-associated molecular pattern (DAMP) molecules. With a large potential for synergism or convergence between their signaling pathways, PRRs orchestrate a complex interplay of cellular mediators and transcription factors, and thus play a central role in homeostasis and host defense. Aberrant activation of PRR signaling, mutations of the receptors and/or their downstream signaling molecules, and/or DAMP/PAMP complex-mediated receptor signaling can potentially lead to chronic auto-inflammatory diseases or development of cancer. PRR signaling pathways appear to also present an interesting new avenue for the modulation of inflammatory responses and to serve as potential novel therapeutic targets. Evidence for a dysregulation of the PRR toll-like receptor (TLR)2, TLR4, TLR5, and TLR9, nucleotide-binding oligomerization domain-containing protein (NOD)2, and the receptor of advanced glycation end products (RAGE) exists in dogs with chronic enteropathies. We describe the TLR, NOD2, and RAGE signaling pathways and evaluate the current veterinary literature-in comparison to human medicine-to determine the role of TLRs, NOD2, and RAGE in canine chronic enteropathies.

Immunomodulation of classical and non-classical HLA molecules by ionizing radiation.

Science.gov (United States)

Gallegos, Cristina E; Michelin, Severino; Dubner, Diana; Carosella, Edgardo D

2016-05-01

Radiotherapy has been employed for the treatment of oncological patients for nearly a century, and together with surgery and chemotherapy, radiation oncology constitutes one of the three pillars of cancer therapy. Ionizing radiation has complex effects on neoplastic cells and on tumor microenvironment: beyond its action as a direct cytotoxic agent, tumor irradiation triggers a series of alterations in tumoral cells, which includes the de novo synthesis of particular proteins and the up/down-regulation of cell surface molecules. Additionally, ionizing radiation may induce the release of "danger signals" which may, in turn lead to cellular and molecular responses by the immune system. This immunomodulatory action of ionizing radiation highlights the importance of the combined use (radiotherapy plus immunotherapy) for cancer healing. Major histocompatibility complex antigens (also called Human Leukocyte Antigens, HLA in humans) are one of those molecules whose expression is modulated after irradiation. This review summarizes the modulatory properties of ionizing radiation on the expression of HLA class I (classical and non-classical) and class II molecules, with special emphasis in non-classical HLA-I molecules. Copyright © 2016 Elsevier Inc. All rights reserved.