scholarly journals tRNA Modification Profiles and Codon-Decoding Strategies in Methanocaldococcus jannaschii

2019 ◽  
Vol 201 (9) ◽  
Author(s):  
Ningxi Yu ◽  
Manasses Jora ◽  
Beulah Solivio ◽  
Priti Thakur ◽  
Carlos G. Acevedo-Rocha ◽  
...  
Keyword(s):  
Critical Role ◽  
Rna Modification ◽  
Trna Modification ◽  
High Quality ◽  
Methanocaldococcus Jannaschii ◽  
Content Type ◽  
Trna Modifications ◽  
Posttranscriptional Modifications ◽  
Eukaryotic Organisms ◽  
Decoding Efficiency

ABSTRACT tRNAs play a critical role in mRNA decoding, and posttranscriptional modifications within tRNAs drive decoding efficiency and accuracy. The types and positions of tRNA modifications in model bacteria have been extensively studied, and tRNA modifications in a few eukaryotic organisms have also been characterized and localized to particular tRNA sequences. However, far less is known regarding tRNA modifications in archaea. While the identities of modifications have been determined for multiple archaeal organisms, Haloferax volcanii is the only organism for which modifications have been extensively localized to specific tRNA sequences. To improve our understanding of archaeal tRNA modification patterns and codon-decoding strategies, we have used liquid chromatography and tandem mass spectrometry to characterize and then map posttranscriptional modifications on 34 of the 35 unique tRNA sequences of Methanocaldococcus jannaschii. A new posttranscriptionally modified nucleoside, 5-cyanomethyl-2-thiouridine (cnm5s2U), was discovered and localized to position 34. Moreover, data consistent with wyosine pathway modifications were obtained beyond the canonical tRNAPhe as is typical for eukaryotes. The high-quality mapping of tRNA anticodon loops enriches our understanding of archaeal tRNA modification profiles and decoding strategies. IMPORTANCE While many posttranscriptional modifications in M. jannaschii tRNAs are also found in bacteria and eukaryotes, several that are unique to archaea were identified. By RNA modification mapping, the modification profiles of M. jannaschii tRNA anticodon loops were characterized, allowing a comparative analysis with H. volcanii modification profiles as well as a general comparison with bacterial and eukaryotic decoding strategies. This general comparison reveals that M. jannaschii, like H. volcanii, follows codon-decoding strategies similar to those used by bacteria, although position 37 appears to be modified to a greater extent than seen in H. volcanii.

Untangling the antecedents of code of ethics quality: does corporate governance matter?

2015 ◽  
Vol 15 (5) ◽  
pp. 607-622 ◽  
Author(s):  
Giovanni Maria Garegnani ◽  
Emilia Piera Merlotti ◽  
Angeloantonio Russo
Keyword(s):  
Corporate Governance ◽  
Code Of Ethics ◽  
Critical Role ◽  
Codes Of Ethics ◽  
Strategic Decision ◽  
Independent Directors ◽  
High Quality ◽  
Board Size ◽  
Content Type ◽  
Ceo Age

Purpose – This study aims to investigate the antecedents of code of ethics’ quality with specific regard to the peculiarities of corporate governance, which include the role of the primary shareholders within the firm, the role and influence of independent directors on the board, the effect of board size on the strategic decision-making process and the influence of the chief executive officer’s (CEO) age and gender diversity. Design/methodology/approach – A sample of 248 Italian public companies publishing a code of ethics as of 2011 is used to test the hypotheses through Tobit regression models. Findings – A positive or negative impact is derived from the implementation of a high-quality code of ethics. Codes of ethics are strongly influenced by the ownership structure of the company given the critical role played by primary shareholders with larger stakes in influencing the quality of a code. Moreover, the lower the number of independent directors, the higher the firm’s propensity to invest in code of ethics’ quality. Similar results were found in relation to board size and CEO age, where smaller boards and younger CEOs are more inclined to implement higher-quality codes of ethics. Originality/value – Results support the argument that when linked to a sustainability strategic orientation focused on a high-quality code of ethics, corporate governance characteristics reveal influences that differ from those found in prior literature.

scholarly journals Optimising quantity of manufacturing and remanufacturing in an electric vehicle battery closed-loop supply chain

2018 ◽  
Vol 118 (1) ◽  
pp. 283-302 ◽  
Author(s):  
Xiaoyu Gu ◽  
Petros Ieromonachou ◽  
Li Zhou ◽  
Ming-Lang Tseng
Keyword(s):  
Supply Chain ◽  
Closed Loop ◽  
Raw Materials ◽  
Critical Role ◽  
Purchase Price ◽  
High Quality ◽  
Closed Loop Supply Chain ◽  
Content Type ◽  
Period 2 ◽  
The Individual

Purpose Batteries installed on electric vehicles (EVs) should normally be removed when their capacity falls to 70-80 per cent, but they are still usable for other purposes, such as energy storage. This paper studies an EV battery closed-loop supply chain (CLSC) consisting of a battery manufacturer and a remanufacturer. The manufacturer produces new batteries by using natural resources, while the remanufacturer collects returned batteries and makes decisions based on the return quality, that is, to reuse or recycle. The purpose of this paper is to maximise the individual profits through optimising the amount of manufacturing and remanufacturing, respectively, and optimising the purchase price of returned batteries. Design/methodology/approach Based on the Nash equilibrium, this paper develops a three-period model in the CLSC. In period 1, batteries are made from raw materials; in period 2, returned batteries from period 1 are sorted into low quality and high quality. Some high-quality returns can be reused for other purposes while those non-reusable returns are recycled into materials. In period 3, all the returns are recycled into materials. The analytical results are derived. Findings The result of the analyses suggest that first, among the variables that affect the (re-)manufacturing decision, the purchase price for returned batteries plays a critical role. In particular, the price of low-quality returns has more influence than the price of high quality returns. Second, the higher purchase price for re-usable returns does not necessarily lead to a higher return rate of reusable returns. Third, the manufacturer’s profit is normally higher than the remanufacturer’s. This suggests the need to design incentives to promote the remanufacturing sector. And finaly, although it is appreciated that maximising the utilisation of batteries over the life-cycle would benefit the environment, the economic benefit needs further investigation. Originality/value Although the CLSC has been widely studied, studies on the EV battery CLSC are scarce. The EV battery CLSC is particularly challenging in terms of the reusability of returns because used EV batteries cannot be reused for the original purpose, which complicates CLSC operations. This paper explores the interrelationship between manufacturer and remanufacturer, explaining the reasons why recycling is still underdeveloped, and suggests the possibility of enhancing remanufacturing profitability.

scholarly journals A Critical Role for the Putative NCS2 Nucleobase Permease YjcD in the Sensitivity of Escherichia coli to Cytotoxic and Mutagenic Purine Analogs

mBio ◽  
2013 ◽  
Vol 4 (6) ◽  
Author(s):  
Stanislav G. Kozmin ◽  
Elena I. Stepchenkova ◽  
Stephen C. Chow ◽  
Roel M. Schaaper
Keyword(s):  
Escherichia Coli ◽  
Critical Role ◽  
Nucleotide Metabolism ◽  
Mutagenic Action ◽  
Gene Encoding ◽  
Content Type ◽  
Purine Bases ◽  
High Affinity ◽  
Purine Analogs ◽  
Eukaryotic Organisms

ABSTRACTThe base analogs 6-N-hydroxylaminopurine (HAP) and 2-amino-HAP (AHAP) are potent mutagens in bacteria and eukaryotic organisms. Previously, we demonstrated that a defect in theEscherichia coli ycbXgene, encoding a molybdenum cofactor-dependent oxidoreductase, dramatically enhances sensitivity to the toxic and mutagenic action of these agents. In the present study, we describe the discovery and properties of a novel suppressor locus,yjcD, that strongly reduces the HAP sensitivity of theycbXstrain. Suppressor effects are also observed for other purine analogs, like AHAP, 6-mercaptopurine, 6-thioguanine, and 2-aminopurine. In contrast, theyjcDdefect did not affect the sensitivity to the pyrimidine analog 5-fluorouracil. Homology searches have predicted thatyjcDencodes a putative permease of the NCS2 family of nucleobase transporters. We further investigated the effects of inactivation of all other members of the NCS2 family, XanQ, XanP, PurP, UacT, UraA, RutG, YgfQ, YicO, and YbbY, and of the NCS1 family nucleobase permeases CodB and YbbW. None of these other defects significantly affected sensitivity to either HAP or AHAP. The combined data strongly suggest that YjcD is the primary importer for modified purine bases. We also present data showing that this protein may, in fact, also be a principal permease involved in transport of the normal purines guanine, hypoxanthine, and/or xanthine.IMPORTANCENucleotide metabolism is a critical aspect of the overall metabolism of the cell, as it is central to the core processes of RNA and DNA synthesis. At the same time, nucleotide metabolism can be subverted by analogs of the normal DNA or RNA bases, leading to highly toxic and mutagenic effects. Thus, understanding how cells process both normal and modified bases is of fundamental importance. This work describes a novel suppressor of the toxicity of certain modified purine bases in the bacteriumEscherichia coli. This suppressor encodes a putative high-affinity nucleobase transporter that mediates the import of the modified purine bases. It is also a likely candidate for the long-sought high-affinity importer for the normal purines, like guanine and hypoxanthine.

The cultural similarities of work as dignity: bringing sense of community in business organizations

2015 ◽  
Vol 29 (4) ◽  
pp. 6-9 ◽  
Author(s):  
Ralph Palliam ◽  
Robert Ankli
Keyword(s):  
Cultural Values ◽  
High Performance ◽  
Theoretical Foundation ◽  
Critical Role ◽  
Well Being ◽  
Management Theory ◽  
High Quality ◽  
Content Type ◽  
Self Worth ◽  
Conceptual Paper

Purpose – The pursuit of the culture of work as dignity is rarely a focus of scholarly writings. One dominant, widely shared and accepted cultural value of work ethic is the belief that it is work that accords dignity to a human being. While seemingly neglected in traditional management research, the concepts of dignity and well-being have experienced renewed attention from the humanities and social sciences. The ability to utilize this sense of dignity becomes a critical role of human resources in advancing self-worth and self-respect. The relationships between worker and management are considered within the culture of work as dignity. Design/methodology/approach – This is a conceptual paper. A theoretical foundation of work as dignity is developed. It is uses Hofstede’s analysis of work-related cultural values in different countries. Work is identified as dignity that is equated to a universal property like the doctrine of modern democracy that is enjoyed by other societies. Findings – If work accords dignity to humans, the ability to establish a sense of employee self-worth and self-respect and to enjoy the respect of others becomes critical objectives of management. This notion results in moving high-performance workplaces to high quality workplaces resulting in managerial conduct that is fair, equitable, reasonable and just. This paper is a call to rethink management theory from a humanistic perspective and highlights the role and protection of human dignity as a cornerstone in management theory. The concept of dignity elevates human responsibilities to the degree that they support the promotion of well-being. Research limitations/implications – This is a conceptual paper. A rigorous empirical study needs to be conducted to substantiate the theoretical foundation. Practical implications – Guidance is offered to managerial responsibility in promoting work as dignity, support for work as dignity, maintaining the dominant culture of work as dignity and identifying high-performance versus high-quality workplace. Social implications – Dignity is a virtue. Cultural differences play a less meaningful role and individuals become more alike than unalike. Together with the dictates of modernizing technology, there is a measure of uniformity to how everyone approaches the world. Originality/value – This study adds value in a somewhat different vein by presenting dignity as a central purpose of human life. This paper is a call to rethink management theory from a humanistic perspective and highlights the role and protection of human. The ability to establish a sense of employee self-worth and self-respect and to enjoy the respect of others becomes critical objectives of management. Moving high-performance workplaces to high-quality workplaces results in management conduct that is fair, equitable, reasonable and just. Human responsibilities need to be elevated to a degree that they support the promotion of well-being.

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 Squalene-Hopene Cyclases

2011 ◽  
Vol 77 (12) ◽  
pp. 3905-3915 ◽  
Author(s):  
Gabriele Siedenburg ◽  
Dieter Jendrossek
Keyword(s):  
Common Ancestor ◽  
Amino Acid Sequences ◽  
Enzymatic Reactions ◽  
Covalent Bonds ◽  
Content Type ◽  
Oxidosqualene Cyclase ◽  
Ring Structures ◽  
One Step ◽  
Alicyclobacillus Acidocaldarius ◽  
Eukaryotic Organisms

ABSTRACTHopanoids and sterols are members of a large group of cyclic triterpenoic compounds that have important functions in many prokaryotic and eukaryotic organisms. They are biochemically synthesized from linear precursors (squalene, 2,3-oxidosqualene) in only one enzymatic step that is catalyzed by squalene-hopene cyclase (SHC) or oxidosqualene cyclase (OSC). SHCs and OSCs are related in amino acid sequences and probably are derived from a common ancestor. The SHC reaction requires the formation of five ring structures, 13 covalent bonds, and nine stereo centers and therefore is one of the most complex one-step enzymatic reactions. We summarize the knowledge of the properties of triterpene cyclases and details of the reaction mechanism ofAlicyclobacillus acidocaldariusSHC. Properties of other SHCs are included.

Healthcare supply chain management: literature review and some issues

2018 ◽  
Vol 15 (3) ◽  
pp. 265-287 ◽  
Author(s):  
Bhavana Mathur ◽  
Sumit Gupta ◽  
Makhan Lal Meena ◽  
G.S. Dangayach
Keyword(s):  
Supply Chain ◽  
Supply Chain Management ◽  
Literature Review ◽  
Organizational Performance ◽  
Critical Role ◽  
Sample Survey ◽  
Future Research ◽  
Chain Management ◽  
Content Type ◽  
Potential Benefits

PurposeThe purpose of this paper is to examine the causal linkages among supply chain practices, effectiveness of supply chain performance (SCP) and organizational performance (OP) in Indian healthcare industries.Design/methodology/approachThis paper is helpful in developing a framework for linking a healthcare supply chain practice to its OP, and thus identifies how such a linkage can be connected to the effectiveness of SCP. Such effort also enables the authors to derive a set of recommended supply chain practices for SC performance.FindingsFrom the literature review, this paper finds that, in the context of Indian healthcare industries, efficient SC performance may play a critical role for overall OP improvement, as there is a close interrelationship between supply chain management (SCM) practices and SCP that may have a more significant effect on OP improvement.Research limitations/implicationsThe principle limitation of the paper is that it is performed only in a particular industry and with a questionnaire survey which could be extended in future for other industries also. Another limitation of the paper is that it is focused only on the SCP of medical device and equipment supply chain which is a small portion of the whole healthcare supply chain, and therefore requires further research covering various other domains of healthcare supply chain. Another limitation of the study is that the sample survey has been taken from only one respondent per company at one point of time which may create biasness in the results. Thus, future research should collect data through multiple members from the organization.Practical implicationsThis study contributes to know the effect of SCM practices on healthcare SCP and provides a practical and useful tool to evaluate the extent of effectiveness of SCP and finally their impact on the healthcare OP. Finally, this study provides conceptual and descriptive literature regarding SCM practices that leads to improvement in healthcare performance.Social implicationsThis study adds to the knowledge on healthcare SCM performance by exploring the relationship between supply chain practices, healthcare SCP and healthcare OP and by developing and testing a research framework thus help in improving patient satisfaction.Originality/valueThis study attempts to show how the potential benefits of supply chain practices can no longer be ignored in healthcare supply chain.

scholarly journals Titan Cells Confer Protection from Phagocytosis in Cryptococcus neoformans Infections

2012 ◽  
Vol 11 (6) ◽  
pp. 820-826 ◽  
Author(s):  
Laura H. Okagaki ◽  
Kirsten Nielsen
Keyword(s):  
Cryptococcus Neoformans ◽  
Critical Role ◽  
Cell Formation ◽  
Pulmonary Cryptococcosis ◽  
Content Type ◽  
Cell Production ◽  
Human Fungal Pathogen ◽  
Large Size ◽  
Large Particles ◽  
The Relationship

ABSTRACTThe human fungal pathogenCryptococcus neoformansproduces an enlarged “titan” cell morphology when exposed to the host pulmonary environment. Titan cells exhibit traits that promote survival in the host. Previous studies showed that titan cells are not phagocytosed and that increased titan cell production in the lungs results in reduced phagocytosis of cryptococcal cells by host immune cells. Here, the effect of titan cell production on host-pathogen interactions during early stages of pulmonary cryptococcosis was explored. The relationship between titan cell production and phagocytosis was found to be nonlinear; moderate increases in titan cell production resulted in profound decreases in phagocytosis, with significant differences occurring within the first 24 h of the infection. Not only were titan cells themselves protected from phagocytosis, but titan cell formation also conferred protection from phagocytosis to normal-size cryptococcal cells. Large particles introduced into the lungs were not phagocytosed, suggesting the large size of titan cells protects against phagocytosis. The presence of large particles was unable to protect smaller particles from phagocytosis, revealing that titan cell size alone is not sufficient to provide the observed cross-protection of normal-size cryptococcal cells. These data suggest that titan cells play a critical role in establishment of the pulmonary infection by promoting the survival of the entire population of cryptococcal cells.

scholarly journals A Novel Gene Involved in the Survival of Streptococcus mutans under Stress Conditions

2013 ◽  
Vol 80 (1) ◽  
pp. 97-103 ◽  
Author(s):  
Dan Li ◽  
Yukie Shibata ◽  
Toru Takeshita ◽  
Yoshihisa Yamashita
Keyword(s):  
Streptococcus Mutans ◽  
Streptococcus Pyogenes ◽  
Biofilm Formation ◽  
Acid Tolerance ◽  
Stress Conditions ◽  
Insertion Mutagenesis ◽  
Trna Modification ◽  
Content Type ◽  
Virulence Proteins ◽  
Random Insertion

ABSTRACTAStreptococcus mutansmutant defective in aciduricity was constructed by random-insertion mutagenesis. Sequence analysis of the mutant revealed a mutation ingidA, which is known to be involved in tRNA modification inStreptococcus pyogenes. Complementation ofgidAbyS. pyogenesgidArecovered the acid tolerance ofS. mutans. Although thegidA-inactivatedS. pyogenesmutant exhibited significantly reduced expression of multiple extracellular virulence proteins, theS. mutansmutant did not. On the other hand, thegidAmutant ofS. mutansshowed reduced ability to withstand exposure to other stress conditions (high osmotic pressure, high temperature, and bacitracin stress) besides an acidic environment. In addition, loss of GidA decreased the capacity for glucose-dependent biofilm formation by over 50%. This study revealed thatgidAplays critical roles in the survival ofS. mutansunder stress conditions, including lower pH.

Juggling on the line

2015 ◽  
Vol 37 (4) ◽  
pp. 459-474 ◽  
Author(s):  
Samantha Evans
Keyword(s):  
Critical Role ◽  
Case Study Research ◽  
Critical Factor ◽  
Employee Relations ◽  
Front Line ◽  
Structured Interviews ◽  
Line Managers ◽  
Content Type ◽  
Nuanced Understanding ◽  
High Level

Purpose – The purpose of this paper is to examine the interplay between the role of front line managers (FLMs) and their contribution to the reported gap between intended and actual human resource management (HRM). Design/methodology/approach – The findings draw on case study research using 51 semi-structured interviews with managers across two UK retail organisations between 2012 and 2013. Findings – This paper argues that FLMs are key agents in people management and play a critical role in the gap between intended and actual employee relations (ER) and HRM. The research found that these managers held a high level of responsibility for people management, but experienced a lack of institutional support, monitoring or incentives to implement according to central policy. This provided an opportunity for them to modify or resist intended policy and the tensions inherent in their role were a critical factor in this manipulation of their people management responsibilities. Research limitations/implications – The data were collected from only one industry and two organisations so the conclusions need to be considered within these limitations. Practical implications – Efforts to address the gap between intended and actual ER/HRM within organisations will need to consider the role tensions of both front line and middle managers. Originality/value – This research provides a more nuanced understanding of the interplay between FLMs and the gap between intended and actual HRM within organisations. It addresses the issue of FLMs receiving less attention in the HRM-line management literature and the call to research their role in the translation of policy into practice.

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