scholarly journals Environmental Sensing in Actinobacteria: a Comprehensive Survey on the Signaling Capacity of This Phylum

2015 ◽  
Vol 197 (15) ◽  
pp. 2517-2535 ◽  
Author(s):  
Xiaoluo Huang ◽  
Daniela Pinto ◽  
Georg Fritz ◽  
Thorsten Mascher
Keyword(s):  
Signal Transduction ◽  
Experimental Studies ◽  
Sequence Information ◽  
Content Type ◽  
Making Sense ◽  
Component Systems ◽  
Comprehensive Survey ◽  
Signal Transduction Proteins ◽  
Treasure Chest ◽  
Signaling Strategies

ABSTRACTSignal transduction is an essential process that allows bacteria to sense their complex and ever-changing environment and adapt accordingly. Three distinct major types of signal-transducing proteins (STPs) can be distinguished: one-component systems (1CSs), two-component systems (2CSs), and extracytoplasmic-function σ factors (ECFs). SinceActinobacteriaare particularly rich in STPs, we comprehensively investigated the abundance and diversity of STPs encoded in 119 actinobacterial genomes, based on the data stored in the Microbial Signal Transduction (MiST) database. Overall, we observed an approximately linear correlation between the genome size and the total number of encoded STPs. About half of all membrane-anchored 1CSs are protein kinases. For both 1CSs and 2CSs, a detailed analysis of the domain architectures identified novel proteins that are found only in actinobacterial genomes. Many actinobacterial genomes are particularly enriched for ECFs. As a result of this study, almost 500 previously unclassified ECFs could be classified into 18 new ECF groups. This comprehensive survey demonstrates that actinobacterial genomes encode previously unknown STPs, which may represent new mechanisms of signal transduction and regulation. This information not only expands our knowledge of the diversity of bacterial signal transduction but also provides clear and testable hypotheses about their mechanisms, which can serve as starting points for experimental studies.IMPORTANCEIn the wake of the genomic era, with its enormous increase in the amount of available sequence information, the challenge has now shifted toward making sense and use of this treasure chest. Such analyses are a prerequisite to provide meaningful information that can help guide subsequent experimental efforts, such as mechanistic studies on novel signaling strategies. This work provides a comprehensive analysis of signal transduction proteins from 119 actinobacterial genomes. We identify, classify, and describe numerous novel and conserved signaling devices. Hence, our work serves as an important resource for any researcher interested in signal transduction of this important bacterial phylum, which contains organisms of ecological, biotechnological, and medical relevance.

scholarly journals The ChrSA and HrrSA Two-Component Systems Are Required for Transcriptional Regulation of thehemAPromoter in Corynebacterium diphtheriae

2016 ◽  
Vol 198 (18) ◽  
pp. 2419-2430 ◽  
Author(s):  
Jonathan M. Burgos ◽  
Michael P. Schmitt
Keyword(s):  
Signal Transduction ◽  
Kinase Activity ◽  
Content Type ◽  
Component Systems ◽  
Two Component ◽  
Two Component Signal Transduction ◽  
Two Component Systems ◽  
Signal Transduction Systems

ABSTRACTCorynebacterium diphtheriaeutilizes heme and hemoglobin (Hb) as iron sources for growth in low-iron environments. InC. diphtheriae, the two-component signal transduction systems (TCSs) ChrSA and HrrSA are responsive to Hb levels and regulate the transcription of promoters forhmuO,hrtAB, andhemA. ChrSA and HrrSA activate transcription at thehmuOpromoter and repress transcription athemAin an Hb-dependent manner. In this study, we show that HrrSA is the predominant repressor athemAand that its activity results in transcriptional repression in the presence and absence of Hb, whereas repression ofhemAby ChrSA is primarily responsive to Hb. DNA binding studies showed that both ChrA and HrrA bind to thehemApromoter region at virtually identical sequences. ChrA binding was enhanced by phosphorylation, while binding to DNA by HrrA was independent of its phosphorylation state. ChrA and HrrA are phosphorylatedin vitroby the sensor kinase ChrS, whereas no kinase activity was observed with HrrSin vitro. Phosphorylated ChrA was not observedin vivo, even in the presence of Hb, which is likely due to the instability of the phosphate moiety on ChrA. However, phosphorylation of HrrA was observedin vivoregardless of the presence of the Hb inducer, and genetic analysis indicates that ChrS is responsible for most of the phosphorylation of HrrAin vivo. Phosphorylation studies strongly suggest that HrrS functions primarily as a phosphatase and has only minimal kinase activity. These findings collectively show a complex mechanism of regulation at thehemApromoter, where both two-component systems act in concert to optimize expression of heme biosynthetic enzymes.IMPORTANCEUnderstanding the mechanism by which two-component signal transduction systems function to respond to environmental stimuli is critical to the study of bacterial pathogenesis. The current study expands on the previous analyses of the ChrSA and HrrSA TCSs in the human pathogenC. diphtheriae. The findings here underscore the complex interactions between the ChrSA and HrrSA systems in the regulation of thehemApromoter and demonstrate how the two systems complement one another to refine and control transcription in the presence and absence of Hb.

scholarly journals Transcriptional repressors

2006 ◽  
Vol 27 (3) ◽  
pp. 105
Author(s):  
Charlene Kahler
Keyword(s):  
Signal Transduction ◽  
Signal Transduction Pathways ◽  
Transcriptional Repressors ◽  
Response Regulators ◽  
Cellular Functions ◽  
Histidine Kinases ◽  
Component Systems ◽  
Prokaryotic Genomes ◽  
Two Component Systems ◽  
Signal Transduction Proteins

Prokaryotes regulate cellular functions in response to environmental cues via signal transduction pathways. In principal, there are two thematic organisations of signal transduction proteins: ? One-component proteins, in which the input and output domains are physically linked. These are commonly called activators (see article by Schubert & Shearwin) and repressors (reviewed in this article). ? Two-component systems consisting of histidine kinases and response regulators (see article by Cheung & Rood). A recent survey of 145 prokaryotic genomes has revealed the predominance of one-component systems in this domain of life and has provided the first indication of the diversity inherent in these signal transduction pathways.

scholarly journals Divergence in Coding Sequence and Expression of Different Functional Categories of Immune Genes between Two Wild Rodent Species

2021 ◽  
Vol 13 (3) ◽  
Author(s):  
Xiuqin Zhong ◽  
Max Lundberg ◽  
Lars Råberg
Keyword(s):  
Signal Transduction ◽  
Transcription Factors ◽  
Immune Function ◽  
Sequence Divergence ◽  
Expression Divergence ◽  
Functional Categories ◽  
Coding Sequence ◽  
Immune Genes ◽  
Genes Encoding ◽  
Signal Transduction Proteins

Abstract Differences in immune function between species could be a result of interspecific divergence in coding sequence and/or expression of immune genes. Here, we investigate how the degree of divergence in coding sequence and expression differs between functional categories of immune genes, and if differences between categories occur independently of other factors (expression level, pleiotropy). To this end, we compared spleen transcriptomes of wild-caught yellow-necked mice and bank voles. Immune genes expressed in the spleen were divided into four categories depending on the function of the encoded protein: pattern recognition receptors (PRR); signal transduction proteins; transcription factors; and cyto- and chemokines and their receptors. Genes encoding PRR and cyto-/chemokines had higher sequence divergence than genes encoding signal transduction proteins and transcription factors, even when controlling for potentially confounding factors. Genes encoding PRR also had higher expression divergence than genes encoding signal transduction proteins and transcription factors. There was a positive correlation between expression divergence and coding sequence divergence, in particular for PRR genes. We propose that this is a result of that divergence in PRR coding sequence leads to divergence in PRR expression through positive feedback of PRR ligand binding on PRR expression. When controlling for sequence divergence, expression divergence of PRR genes did not differ from other categories. Taken together, the results indicate that coding sequence divergence of PRR genes is a major cause of differences in immune function between species.

scholarly journals Opportunistic Large Array Propagation Models: A Comprehensive Survey

Sensors ◽  
2021 ◽  
Vol 21 (12) ◽  
pp. 4206
Author(s):  
Farhan Nawaz ◽  
Hemant Kumar ◽  
Syed Ali Hassan ◽  
Haejoon Jung
Keyword(s):  
Energy Efficient ◽  
Large Scale ◽  
Performance Metrics ◽  
Experimental Studies ◽  
Cooperative Transmission ◽  
Analytical Models ◽  
Future Research ◽  
Large Array ◽  
Propagation Models ◽  
Comprehensive Survey

Enabled by the fifth-generation (5G) and beyond 5G communications, large-scale deployments of Internet-of-Things (IoT) networks are expected in various application fields to handle massive machine-type communication (mMTC) services. Device-to-device (D2D) communications can be an effective solution in massive IoT networks to overcome the inherent hardware limitations of small devices. In such D2D scenarios, given that a receiver can benefit from the signal-to-noise-ratio (SNR) advantage through diversity and array gains, cooperative transmission (CT) can be employed, so that multiple IoT nodes can create a virtual antenna array. In particular, Opportunistic Large Array (OLA), which is one type of CT technique, is known to provide fast, energy-efficient, and reliable broadcasting and unicasting without prior coordination, which can be exploited in future mMTC applications. However, OLA-based protocol design and operation are subject to network models to characterize the propagation behavior and evaluate the performance. Further, it has been shown through some experimental studies that the most widely-used model in prior studies on OLA is not accurate for networks with networks with low node density. Therefore, stochastic models using quasi-stationary Markov chain are introduced, which are more complex but more exact to estimate the key performance metrics of the OLA transmissions in practice. Considering the fact that such propagation models should be selected carefully depending on system parameters such as network topology and channel environments, we provide a comprehensive survey on the analytical models and framework of the OLA propagation in the literature, which is not available in the existing survey papers on OLA protocols. In addition, we introduce energy-efficient OLA techniques, which are of paramount importance in energy-limited IoT networks. Furthermore, we discuss future research directions to combine OLA with emerging technologies.

Determinants of housing demand in the Erzurum province, Turkey

2014 ◽  
Vol 7 (4) ◽  
pp. 586-602 ◽  
Author(s):  
Erkan Oktay ◽  
Abdulkerim Karaaslan ◽  
Ömer Alkan ◽  
Ali Kemal Çelik
Keyword(s):  
Housing Prices ◽  
Binary Logistic Regression ◽  
Housing Demand ◽  
Outcome Variable ◽  
Binary Logistic Regression Analysis ◽  
Cross Sectional Survey ◽  
Cross Sectional ◽  
Content Type ◽  
Comprehensive Survey ◽  
Income Expectations

Purpose – The main aim of this study is to determine the factors that influence the housing demand of households in Erzurum, northeastern Turkey. Housing demand is generally affected by several factors including housing prices, individuals’ income, expectations and choices and so on, as a means of its demographic and socio-psychological contexts. Design/methodology/approach – A questionnaire-based cross-sectional survey was carried out, in which the outcome variable had binary responses such as whether to invest in housing or not. A binary logistic regression analysis was performed to estimate the underlying data. Findings – The questionnaire was conducted in 2,927 households living in Erzurum city center, and 47 per cent of the respondents claimed that they would consider investing in housing in the future. The estimation results reveal that demographic or socio-economic factors that may possibly influence housing demand of the respondents are as follows: household head’s and spouse’s occupation, monthly income, the number of individuals in the family and car ownership. Originality/value – This paper involves the most comprehensive survey addressing the housing demand in the East Anatolian Region, Turkey. Additionally, this paper aims to contribute to the existing housing literature through establishing the statistical analysis of housing demand in an unstudied territory of the world.

scholarly journals A Developmentally Regulated Gene, ASI2, Is Required for Endocycling in the Macronuclear Anlagen of Tetrahymena

2010 ◽  
Vol 9 (9) ◽  
pp. 1343-1353 ◽  
Author(s):  
Lihui Yin ◽  
Susan T. Gater ◽  
Kathleen M. Karrer
Keyword(s):  
Signal Transduction ◽  
Mitotic Cycle ◽  
Tetrahymena Thermophila ◽  
Germ Line ◽  
Ciliated Protozoa ◽  
Dna Rearrangement ◽  
Developmentally Regulated ◽  
Content Type ◽  
Molecular Events ◽  
Multicellular Organisms

ABSTRACT Ciliated protozoa contain two types of nuclei, germ line micronuclei (Mic) and transcriptionally active macronuclei (Mac). During sexual reproduction, the parental Mac degenerates and a new Mac develops from a mitotic product of the zygotic Mic. Macronuclear development involves extensive endoreplication of the genome. The present study shows that endoreplication of macronuclear DNA in Tetrahymena is an example of endocyling, a variant of the mitotic cycle with alternating S and G phases in the absence of cell division. Thus, endocycling is conserved from ciliates to multicellular organisms. The gene ASI2 in Tetrahymena thermophila encodes a putative signal transduction receptor. ASI2 is nonessential for vegetative growth, but it is upregulated during development of the new Mac. Cells that lack ASI2 in the developing Mac anlagen are arrested in endoreplication of the DNA and die. This study shows that ASI2 is also transcribed in the parental Mac early in conjugation and that transcription of ASI2 in the parental Mac supports endoreplication of the DNA during early stages of development of the Mac anlagen. Other molecular events in Mac anlage development, including developmentally regulated DNA rearrangement, occur normally in matings between ASI2 knockouts, suggesting that ASI2 specifically regulates endocycling in Tetrahymena.

scholarly journals Direct evidence for a key role of protein kinase C in the development of vasospasm after subarachnoid hemorrhage

1992 ◽  
Vol 76 (4) ◽  
pp. 635-639 ◽  
Author(s):  
Shigeru Nishizawa ◽  
Nobukazu Nezu ◽  
Kenichi Uemura
Keyword(s):  
Signal Transduction ◽  
Protein Kinase C ◽  
Protein Kinase ◽  
Direct Evidence ◽  
Control Group ◽  
Content Type ◽  
Kinase C ◽  
Protein Kinase C Activity ◽  
Fine Print

✓ Vascular contraction is induced by the activation of intracellular contractile proteins mediated through signal transduction from the outside to the inside of cells. Protein kinase C plays a crucial role in this signal transduction. It is hypothesized that protein kinase C plays a causative part in the development of vasospasm after subarachnoid hemorrhage (SAH). To verify this directly, the authors measured protein kinase C activity in canine basilar arteries in an SAH model with (γ-32P)adenosine triphosphate and the data were compared to those in a control group. Protein kinase C is translocated to the membrane from the cytosol when it is activated, and the translocation is an index of the activation; thus, protein kinase C activity was measured both in the cytosol and in the membrane fractions. Protein kinase C activity in the membrane in the SAH model was remarkably enhanced compared to that in the control group. The percentage of membrane activity to the total was also significantly greater in the SAH vessels than in the control group, and the percentage of cytosol activity in the SAH group was decreased compared to that in the control arteries. The results indicate that protein kinase C in the vascular smooth muscle was translocated to the membrane from the cytosol and was activated when SAH occurred. It is concluded that this is direct evidence for a key role of protein kinase C in the development of vasospasm.

Think about it – can portrayals of homosexuality in advertising prime consumer-perceived social connectedness and empathy?

2017 ◽  
Vol 51 (1) ◽  
pp. 82-98 ◽  
Author(s):  
Nina Åkestam ◽  
Sara Rosengren ◽  
Micael Dahlen
Keyword(s):  
Design Methodology ◽  
Social Connectedness ◽  
Experimental Studies ◽  
Social Effects ◽  
Attitudes Toward Homosexuality ◽  
Content Type ◽  
Advantages And Disadvantages ◽  
Thought Listing ◽  
Societal Level ◽  
Practical Implications

Purpose This paper aims to investigate whether portrayals of homosexuality in advertising can generate social effects in terms of consumer-perceived social connectedness and empathy. Design/methodology/approach In three experimental studies, the effects of advertising portrayals of homosexuality were compared to advertising portrayals of heterosexuality. Study 1 uses a thought-listing exercise to explore whether portrayals of homosexuality (vs heterosexuality) can evoke more other-related thoughts and whether such portrayals affect consumer-perceived social connectedness and empathy. Study 2 replicates the findings while introducing attitudes toward homosexuality as a boundary condition and measuring traditional advertising effects. Study 3 replicates the findings while controlling for gender, perceived similarity and targetedness. Findings The results show that portrayals of homosexuality in advertising can prime consumers to think about other people, thereby affecting them socially. In line with previous studies of portrayals of homosexuality in advertising, these effects are moderated by attitudes toward homosexuality. Research limitations/implications This paper adds to a growing body of literature on the potentially positive extended effects of advertising. They also challenge some of the previous findings regarding homosexuality in advertising. Practical implications The finding that portrayals of homosexuality in advertising can (at least, temporarily) affect consumers socially in terms of social connectedness and empathy should encourage marketers to explore the possibilities of creating advertising that benefits consumers and brands alike. Originality/value The paper challenges the idea that the extended effects of advertising have to be negative. By showing how portrayals of homosexuality can increase social connectedness and empathy, it adds to the discussion of the advantages and disadvantages of advertising on a societal level.

Cultural learning process: lesson from microhistory

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Tianyuan Yu ◽  
Albert J. Mills
Keyword(s):  
Learning Process ◽  
Critical Incident ◽  
Cultural Learning ◽  
Extensive Reading ◽  
Organization Studies ◽  
Content Type ◽  
Knowledge Accumulation ◽  
The Past ◽  
Making Sense ◽  
Historical Accounts

Purpose The purpose of this paper is to examine the cultural learning process (namely, the development, practice and enhancement of cultural intelligence (CQ)) of a successful entrepreneur – Harold Bixby, a Pan American Airways expatriate, as reflected in the memoir of his experiences in China during 1933–1938. Design/methodology/approach This study adopts a microhistory approach as a methodology for studying history and the past while ultimately requiring evaluations informed by the present. This paper first identifies the literature gap on CQ development and the need to study historical accounts of the past in assessing the CQ development process. This study then outlines the four key foci of microhistory as a heuristic for making sense of on-going and past accounts of selected phenomena. Findings This paper finds that specific personality traits (namely, openness to experience and self-efficacy), knowledge accumulation through deep cultural immersion (namely, extensive reading/study, visiting/observation and interacting/conversation), critical incident and metacognition all contributed to Bixby’s CQ development, which was a time-consuming process. Originality/value The study contributes to debates around cultural learning and historical organization studies by providing a rich, qualitative study of CQ assessment and CQ development through microhistory. This study highlights the importance of cognitive CQ and the function of extensive reading/studying in the process of knowledge accumulation. This paper draws attention to critical incidents as an underexplored way of learning tacit knowledge. Moreover, this study suggests metacognitive CQ can be enhanced through meditative and reflexive teaching and research practices. These findings have significant implications for cross-cultural training programs.

Concentration Dependence of the Surface Tension of Three and Four-Component Systems with Peculiarities in the Surface Tension Isotherms of Lateral Binary Melts

2021 ◽  
Vol 1022 ◽  
pp. 194-202
Author(s):  
R.Kh. Dadashev ◽  
R.A. Kutuev
Keyword(s):  
Experimental Data ◽  
Surface Tension ◽  
Concentration Dependence ◽  
Experimental Error ◽  
Binary Systems ◽  
Experimental Studies ◽  
Study Results ◽  
Component Systems ◽  
Minimum Depth ◽  
Surface Tension Isotherms

The experimental study results of the melts concentration dependence of the surface tension of the four-component indium-tin-lead-bismuth system and its constituent binary systems of indium-tin, indium-lead, indium-bismuth, tin-lead, tin-bismuth, lead-bismuth are presented in the paper. It is shown that the concentration dependence of the melts surface tension of the In-Sn-Pb-Bi four-component system can be predicted from the data on ST (surface tension) values of lateral binary systems. Features in the ST isotherms in the form of a minimum are observed only in the indium-tin lateral system from all lateral binaries. A distinctive feature of the detected minimum is that the minimum depth slightly exceeds the experimental error. Therefore, in addition to the fact that the area of average compositions was studied more thoroughly, we carried out the surface tension measurements by two independent methods. The experimental data obtained by both methods coincide within the experimental error and indicate the extremum availability on ST isotherms. Thus, ST experimental studies by two independent methods confirmed the presence of a flat minimum on ST isotherms of the indium-tin binary system increasing the reliability of the obtained data. The obtained outcomes and their comparison with experimental data have shown that the considered models for predicting surface properties based on data due to similar properties of lateral binary systems adequately reflect the experimental dependences. However, the prediction model based on Kohler's method of excess values describes the experimental curves more accurately.

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