scholarly journals Sensory Repertoire of Bacterial Chemoreceptors

2017 ◽  
Vol 81 (4) ◽  
Author(s):  
Álvaro Ortega ◽  
Igor B. Zhulin ◽  
Tino Krell
Keyword(s):  
Model Organisms ◽  
Signal Recognition ◽  
Signaling Mechanism ◽  
Content Type ◽  
Future Studies ◽  
Major Mode ◽  
Bacterial Chemoreceptors ◽  
Different Types ◽  
Chemosensory Pathways ◽  
Genome Analyses

SUMMARY Chemoreceptors in bacteria detect a variety of signals and feed this information into chemosensory pathways that represent a major mode of signal transduction. The five chemoreceptors from Escherichia coli have served as traditional models in the study of this protein family. Genome analyses revealed that many bacteria contain much larger numbers of chemoreceptors with broader sensory capabilities. Chemoreceptors differ in topology, sensing mode, cellular location, and, above all, the type of ligand binding domain (LBD). Here, we highlight LBD diversity using well-established and emerging model organisms as well as genomic surveys. Nearly a hundred different types of protein domains that are found in chemoreceptor sequences are known or predicted LBDs, but only a few of them are ubiquitous. LBDs of the same class recognize different ligands, and conversely, the same ligand can be recognized by structurally different LBDs; however, recent studies began to reveal common characteristics in signal-LBD relationships. Although signals can stimulate chemoreceptors in a variety of different ways, diverse LBDs appear to employ a universal transmembrane signaling mechanism. Current and future studies aim to establish relationships between LBD types, the nature of signals that they recognize, and the mechanisms of signal recognition and transduction.

Development and optimization of coffee gelato: a sensory perspective

2019 ◽  
Vol 121 (5) ◽  
pp. 1116-1124
Author(s):  
Maísa Mancini Matioli de Sousa ◽  
Fabio Antonialli ◽  
Rafaela Corrêa Pereira ◽  
Michele Nayara Ribeiro ◽  
Fabiana de Carvalho Pires ◽  
...  
Keyword(s):  
Design Methodology ◽  
Sensory Attributes ◽  
Purchase Intentions ◽  
Optimal Concentration ◽  
Consumer Acceptance ◽  
Specific Information ◽  
Content Type ◽  
Future Studies ◽  
Different Types ◽  
Soluble Coffee

PurposeThe purpose of this paper is to optimise and characterise the sensory aspects of gelatos flavoured with different types of coffee preparations (brewed, espresso and soluble), to select the most acceptable formulation and investigate the influence of hedonic claims on the consumer acceptance of this product.Design/methodology/approachFirst, the optimal concentration of each coffee type (brewed, soluble and espresso) to be added to the gelato was determined using the just-about-right scale. Second, the acceptance and purchase intentions towards gelatos flavoured with different concentrations of each type of coffee were determined. Finally, the most acceptable concentration for each flavour was selected based on purchase intentions and three other hedonic claims (i.e. texture, flavour and overall impression).FindingsThe estimated optimal concentrations of coffee (in relation to syrup) were found to be 111.09, 135.31 and 59.38 per cent for brewed, espresso and soluble coffee, respectively. Gelatos flavoured with soluble coffee were accepted more readily and associated with higher purchase intentions based on the evaluated sensory attributes (i.e. colour, taste, texture, softness and overall impression). The sensory perceptions towards these gelatos did not change significantly based on the evaluated hedonic claims (“coffee”, “soluble coffee” and “gourmet coffee”). This reveals that consumers may not be influenced by specific information and/or hedonic claims in the case of coffee gelatos.Originality/valueBesides encouraging the availability of a variety of coffee products on the market, this work also supports future studies aimed at the optimization of coffee products from a sensory perspective.

Interorganizational cooperation and eco-innovation: a literature review

2020 ◽  
Vol 12 (5) ◽  
pp. 477-493
Author(s):  
Rafael Morais Pereira ◽  
Maria Laura Ferranty MacLennan ◽  
Eliane Fernandes Tiago
Keyword(s):  
Literature Review ◽  
Web Of Science ◽  
Resource Constraints ◽  
Innovation Development ◽  
Content Type ◽  
Future Studies ◽  
Theoretical Contribution ◽  
Interorganizational Cooperation ◽  
Different Types ◽  
Cooperation Partners

Purpose The presentation of the specificities inherent in the adoption of the cooperation practices for the eco-innovation development is sometimes fragmented and superficial in the literature. So, the purpose of this paper is to analyze how the literature has studied the association between interorganizational cooperation and the development of eco-innovation, for the developing a framework with the different faces of this connection. Design/methodology/approach To achieve the proposed objective, the authors conducted a literature review through the Web of Science database. The selected manuscripts were analyzed from the following categories: Why to cooperate?, What is cooperation?, How to cooperate?, Who to cooperate with?, How much is it worth to cooperate?, Where does cooperation take place?, When to cooperate?, and So what?. Findings Given the proposed objective, as a general aspect highlighted, the analyzed articles revealed that interorganizational cooperation has been presented as relevant for the development of eco-innovations. Thus, cooperation on their different faces allows companies to overcome resource constraints, even partially, while facilitating the development of different types of ecological innovations as costs and risks are reduced. Originality/value The theoretical contribution is expected to be the proposition of a framework capable of systematizing several specificities, including the antecedents and motivations, definitions and cooperation types, cooperation partners, important conditions that highlight how much cooperation is worth, where and when cooperation occurs and, finally, the main insights of this association, to guide future studies.

scholarly journals Identification of a Chemoreceptor for C2and C3Carboxylic Acids

2015 ◽  
Vol 81 (16) ◽  
pp. 5449-5457 ◽  
Author(s):  
Vanina García ◽  
Jose-Antonio Reyes-Darias ◽  
David Martín-Mora ◽  
Bertrand Morel ◽  
Miguel A. Matilla ◽  
...  
Keyword(s):  
Krebs Cycle ◽  
Signaling Cascades ◽  
Model Organisms ◽  
Content Type ◽  
Binding Domains ◽  
Bacterial Chemoreceptors ◽  
Krebs Cycle Intermediates ◽  
And Function ◽  
Equilibrium Dissociation ◽  
Insight Into

ABSTRACTChemoreceptors are at the beginnings of chemosensory signaling cascades that mediate chemotaxis. Most bacterial chemoreceptors are functionally unannotated and are characterized by a diversity in the structure of their ligand binding domains (LBDs). The data available indicate that there are two major chemoreceptor families at the functional level, namely, those that respond to amino acids or to Krebs cycle intermediates. Since pseudomonads show chemotaxis to many different compounds and possess different types of chemoreceptors, they are model organisms to establish relationships between chemoreceptor structure and function. Here, we identify PP2861 (termed McpP) ofPseudomonas putidaKT2440 as a chemoreceptor with a novel ligand profile. We show that the recombinant McpP LBD recognizes acetate, pyruvate, propionate, andl-lactate, withKD(equilibrium dissociation constant) values ranging from 34 to 107 μM. Deletion of themcpPgene resulted in a dramatic reduction in chemotaxis toward these ligands, and complementation restored a native-like phenotype, indicating that McpP is the major chemoreceptor for these compounds. McpP has a CACHE-type LBD, and we present data indicating that CACHE-containing chemoreceptors of other species also mediate taxis to C2and C3carboxylic acids. In addition, the LBD of NbaY ofPseudomonas fluorescens, an McpP homologue mediating chemotaxis to 2-nitrobenzoate, bound neither nitrobenzoates nor the McpP ligands. This work provides further insight into receptor structure-function relationships and will be helpful to annotate chemoreceptors of other bacteria.

scholarly journals Chemoperception of Specific Amino Acids Controls Phytopathogenicity in Pseudomonas syringae pv. tomato

mBio ◽  
2019 ◽  
Vol 10 (5) ◽  
Author(s):  
Jean Paul Cerna-Vargas ◽  
Saray Santamaría-Hernando ◽  
Miguel A. Matilla ◽  
José Juan Rodríguez-Herva ◽  
Abdelali Daddaoua ◽  
...  
Keyword(s):  
Amino Acids ◽  
Pseudomonas Syringae ◽  
Plant Pathogens ◽  
Bacterial Virulence ◽  
Phytopathogenic Bacterium ◽  
Content Type ◽  
Plant Infection ◽  
Bacterial Chemoreceptors ◽  
Plant Signals ◽  
Chemosensory Pathways

ABSTRACT Chemotaxis has been associated with the pathogenicity of bacteria in plants and was found to facilitate bacterial entry through stomata and wounds. However, knowledge regarding the plant signals involved in this process is scarce. We have addressed this issue using Pseudomonas syringae pv. tomato, which is a foliar pathogen that causes bacterial speck in tomato. We show that the chemoreceptor P. syringae pv. tomato PscA (PsPto-PscA) recognizes specifically and with high affinity l-Asp, l-Glu, and d-Asp. The mutation of the chemoreceptor gene largely reduced chemotaxis to these ligands but also altered cyclic di-GMP (c-di-GMP) levels, biofilm formation, and motility, pointing to cross talk between different chemosensory pathways. Furthermore, the PsPto-PscA mutant strain showed reduced virulence in tomato. Asp and Glu are the most abundant amino acids in plants and in particular in tomato apoplasts, and we hypothesize that this receptor may have evolved to specifically recognize these compounds to facilitate bacterial entry into the plant. Infection assays with the wild-type strain showed that the presence of saturating concentrations of d-Asp also reduced bacterial virulence. IMPORTANCE There is substantive evidence that chemotaxis is a key requisite for efficient pathogenesis in plant pathogens. However, information regarding particular bacterial chemoreceptors and the specific plant signal that they sense is scarce. Our work shows that the phytopathogenic bacterium Pseudomonas syringae pv. tomato mediates not only chemotaxis but also the control of pathogenicity through the perception of the plant abundant amino acids Asp and Glu. We describe the specificity of the perception of l- and d-Asp and l-Glu by the PsPto-PscA chemoreceptor and the involvement of this perception in the regulation of pathogenicity-related traits. Moreover, a saturating concentration of d-Asp reduces bacterial virulence, and we therefore propose that ligand-mediated interference of key chemoreceptors may be an alternative strategy to control virulence.

scholarly journals Recent Advances and Future Prospects in Bacterial and Archaeal Locomotion and Signal Transduction

2017 ◽  
Vol 199 (18) ◽  
Author(s):  
Sonia L. Bardy ◽  
Ariane Briegel ◽  
Simon Rainville ◽  
Tino Krell
Keyword(s):  
Signal Transduction ◽  
Protein Complexes ◽  
Model Organism ◽  
Model Organisms ◽  
Content Type ◽  
Research Areas ◽  
Recent Advances ◽  
Wide Range ◽  
Two Component ◽  
Chemosensory Pathways

ABSTRACT The structure and function of two-component and chemotactic signaling and different aspects related to the motility of bacteria and archaea are key research areas in modern microbiology. Escherichia coli is the traditional model organism used to study chemotaxis signaling and motility. However, the recent study of a wide range of bacteria and even some archaea with different lifestyles has provided new insight into the ecophysiology of chemotaxis, which is essential for the establishment of different pathogens or beneficial bacteria in a host. The expanded range of model organisms has also permitted the study of chemosensory pathways unrelated to chemotaxis, multiple chemotaxis pathways within an organism, and new types of chemoreceptors. This research has greatly benefitted from technical advances in the field of cryomicroscopy, which continues to reveal with increasing resolution the complexity and diversity of large protein complexes like the flagellar motor or chemoreceptor arrays. In addition, sensitive instruments now allow an increasing number of experiments to be conducted at the single-cell level, thereby revealing information that is beginning to bridge the gap between individual cells and population behavior. Evidence has also accumulated showing that bacteria have evolved different mechanisms for surface sensing, which appears to be mediated by flagella and possibly type IV pili, and that the downstream signaling involves chemosensory pathways and two-component-system-based processes. Herein, we summarize the recent advances and research tendencies in this field as presented at the latest Bacterial Locomotion and Signal Transduction (BLAST XIV) conference.

scholarly journals Advantages and potential challenges of data management in e-maintenance

2019 ◽  
Vol 25 (3) ◽  
pp. 378-396 ◽  
Author(s):  
Arian Razmi-Farooji ◽  
Hanna Kropsu-Vehkaperä ◽  
Janne Härkönen ◽  
Harri Haapasalo
Keyword(s):  
Data Management ◽  
Design Methodology ◽  
Management Practices ◽  
Future Research ◽  
Conceptual Approach ◽  
Content Type ◽  
Different Types ◽  
Maintenance Systems ◽  
Industry Leader ◽  
Practical Implications

Purpose The purpose of this paper is twofold: first, to understand data management challenges in e-maintenance systems from a holistically viewpoint through summarizing the earlier scattered research in the field, and second, to present a conceptual approach for addressing these challenges in practice. Design/methodology/approach The study is realized as a combination of a literature review and by the means of analyzing the practices on an industry leader in manufacturing and maintenance services. Findings This research provides a general understanding over data management challenges in e-maintenance and summarizes their associated proposed solutions. In addition, this paper lists and exemplifies different types and sources of data which can be collected in e-maintenance, across different organizational levels. Analyzing the data management practices of an e-maintenance industry leader provides a conceptual approach to address identified challenges in practice. Research limitations/implications Since this paper is based on studying the practices of a single company, it might be limited to generalize the results. Future research topics can focus on each of mentioned data management challenges and also validate the applicability of presented model in other companies and industries. Practical implications Understanding the e-maintenance-related challenges helps maintenance managers and other involved stakeholders in e-maintenance systems to better solve the challenges. Originality/value The so-far literature on e-maintenance has been studied with narrow focus to data and data management in e-maintenance appears as one of the less studied topics in the literature. This research paper contributes to e-maintenance by highlighting the deficiencies of the discussion surrounding the perspectives of data management in e-maintenance by studying all common data management challenges and listing different types of data which need to be acquired in e-maintenance systems.

scholarly journals “Artificial Wood” Lignocellulosic Membranes: Influence of Kraft Lignin on the Properties and Gas Transport in Tunicate-Based Nanocellulose Composites

Membranes ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 204
Author(s):  
Ievgen Pylypchuk ◽  
Roman Selyanchyn ◽  
Tetyana Budnyak ◽  
Yadong Zhao ◽  
Mikael Lindström ◽  
...  
Keyword(s):  
Knudsen Diffusion ◽  
Cellulose Nanofibers ◽  
Kraft Lignin ◽  
Separation Processes ◽  
New Approach ◽  
Future Studies ◽  
Different Types ◽  
Molecular Sizes ◽  
Fast Transport ◽  
Cellulose Membranes

Nanocellulose membranes based on tunicate-derived cellulose nanofibers, starch, and ~5% wood-derived lignin were investigated using three different types of lignin. The addition of lignin into cellulose membranes increased the specific surface area (from 5 to ~50 m2/g), however the fine porous geometry of the nanocellulose with characteristic pores below 10 nm in diameter remained similar for all membranes. The permeation of H2, CO2, N2, and O2 through the membranes was investigated and a characteristic Knudsen diffusion through the membranes was observed at a rate proportional to the inverse of their molecular sizes. Permeability values, however, varied significantly between samples containing different lignins, ranging from several to thousands of barrers (10−10 cm3 (STP) cm cm−2 s−1 cmHg−1cm), and were related to the observed morphology and lignin distribution inside the membranes. Additionally, the addition of ~5% lignin resulted in a significant increase in tensile strength from 3 GPa to ~6–7 GPa, but did not change thermal properties (glass transition or thermal stability). Overall, the combination of plant-derived lignin as a filler or binder in cellulose–starch composites with a sea-animal derived nanocellulose presents an interesting new approach for the fabrication of membranes from abundant bio-derived materials. Future studies should focus on the optimization of these types of membranes for the selective and fast transport of gases needed for a variety of industrial separation processes.

Accessing resources for service innovation – the critical role of network relationships

2014 ◽  
Vol 25 (1) ◽  
pp. 2-29 ◽  
Author(s):  
Helena Rusanen ◽  
Aino Halinen ◽  
Elina Jaakkola
Keyword(s):  
Critical Role ◽  
Service Innovation ◽  
Innovation Process ◽  
Research Strategy ◽  
Future Research ◽  
Theoretical Understanding ◽  
Resource Access ◽  
Content Type ◽  
External Resources ◽  
Different Types

Purpose – This paper aims to explore how companies access resources through network relationships when developing service innovations. The paper identifies the types of resource that companies seek from other actors and examines the nature of relationships and resource access strategies that can be applied to access each type of resource. Design/methodology/approach – A longitudinal, multi-case study is conducted in the field of technical business-to-business (b-to-b) services. An abductive research strategy is applied to create a new theoretical understanding of resource access. Findings – Companies seek a range of resources through different types of network relationships for service innovation. Four types of resource access strategies were identified: absorption, acquisition, sharing, and co-creation. The findings show how easily transferable resources can be accessed through weak relationships and low-intensity collaboration. Access to resources that are difficult to transfer, instead, necessitates strong relationships and high-intensity collaboration. Research limitations/implications – The findings are valid for technical b-to-b services, but should also be tested for other kinds of innovations. Future research should also study how actors integrate the resources gained through networks in the innovation process. Practical implications – Managers should note that key resources for service innovation may be accessible through a variety of actors and relationships ranging from formal arrangements to miscellaneous social contacts. To make use of tacit resources such as knowledge, firms need to engage in intensive collaboration. Originality/value – Despite attention paid to network relationships, innovation collaboration, and external resources, previous research has neither linked these issues nor studied their mutual contingencies. This paper provides a theoretical model that characterizes the service innovation resources accessible through different types of relationships and access strategies.

scholarly journals Autophagy-Related Protein ATG8 Has a Noncanonical Function for Apicoplast Inheritance in Toxoplasma gondii

mBio ◽  
2015 ◽  
Vol 6 (6) ◽  
Author(s):  
Maude F. Lévêque ◽  
Laurence Berry ◽  
Michael J. Cipriano ◽  
Hoa-Mai Nguyen ◽  
Boris Striepen ◽  
...  
Keyword(s):  
Toxoplasma Gondii ◽  
Growth Conditions ◽  
Model Organisms ◽  
Secondary Endosymbiosis ◽  
Related Protein ◽  
Content Type ◽  
Superresolution Microscopy ◽  
Animal Pathogens ◽  
Cellular Components ◽  
Catabolic Process

ABSTRACT Autophagy is a catabolic process widely conserved among eukaryotes that permits the rapid degradation of unwanted proteins and organelles through the lysosomal pathway. This mechanism involves the formation of a double-membrane structure called the autophagosome that sequesters cellular components to be degraded. To orchestrate this process, yeasts and animals rely on a conserved set of autophagy-related proteins (ATGs). Key among these factors is ATG8, a cytoplasmic protein that is recruited to nascent autophagosomal membranes upon the induction of autophagy. Toxoplasma gondii is a potentially harmful human pathogen in which only a subset of ATGs appears to be present. Although this eukaryotic parasite seems able to generate autophagosomes upon stresses such as nutrient starvation, the full functionality and biological relevance of a canonical autophagy pathway are as yet unclear. Intriguingly, in T. gondii, ATG8 localizes to the apicoplast under normal intracellular growth conditions. The apicoplast is a nonphotosynthetic plastid enclosed by four membranes resulting from a secondary endosymbiosis. Using superresolution microscopy and biochemical techniques, we show that TgATG8 localizes to the outermost membrane of this organelle. We investigated the unusual function of TgATG8 at the apicoplast by generating a conditional knockdown mutant. Depletion of TgATG8 led to rapid loss of the organelle and subsequent intracellular replication defects, indicating that the protein is essential for maintaining apicoplast homeostasis and thus for survival of the tachyzoite stage. More precisely, loss of TgATG8 led to abnormal segregation of the apicoplast into the progeny because of a loss of physical interactions of the organelle with the centrosomes. IMPORTANCE By definition, autophagy is a catabolic process that leads to the digestion and recycling of eukaryotic cellular components. The molecular machinery of autophagy was identified mainly in model organisms such as yeasts but remains poorly characterized in phylogenetically distant apicomplexan parasites. We have uncovered an unusual function for autophagy-related protein ATG8 in Toxoplasma gondii: TgATG8 is crucial for normal replication of the parasite inside its host cell. Seemingly unrelated to the catabolic autophagy process, TgATG8 associates with the outer membrane of the nonphotosynthetic plastid harbored by the parasite called the apicoplast, and there it plays an important role in the centrosome-driven inheritance of the organelle during cell division. This not only reveals an unexpected function for an autophagy-related protein but also sheds new light on the division process of an organelle that is vital to a group of important human and animal pathogens.

Examination of customer-centric measures among different types of customers in the context of major Canadian ski resort

2018 ◽  
Vol 30 (2) ◽  
pp. 438-459
Author(s):  
Matti J. Haverila ◽  
Kai Christian Haverila
Keyword(s):  
Customer Satisfaction ◽  
Structural Equation ◽  
A Priori ◽  
Equation Modeling ◽  
Marketing Practice ◽  
Content Type ◽  
Ski Resort ◽  
Different Types ◽  
Managerial Implications ◽  
Satisfaction Model

Purpose Customer-centric measures such as customer satisfaction and repurchase intent are important indicators of performance. The purpose of this paper is to examine what is the strength and significance of the path coefficients in a customer satisfaction model consisting of various customer-centric measures for different types of ski resort customer (i.e. day, weekend and ski holiday visitors as well as season pass holders) in a ski resort in Canada. Design/methodology/approach The results were analyzed using the partial least squares structural equation modeling approach for the four different types ski resort visitors. Findings There appeared to differences in the strength and significance in the customer satisfaction model relationships for the four types of ski resort visitors indicating that the a priori managerial classification of the ski resort visitors is warranted. Originality/value The research pinpoints differences in the strength and significance in the relationships between customer-centric measures for four different types ski resort visitors, i.e. day, weekend and ski holiday visitors as well as season pass holders, which have significant managerial implications for the marketing practice of the ski resort.

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