scholarly journals PhoY2 of Mycobacteria Is Required for Metabolic Homeostasis and Stress Response

2012 ◽  
Vol 195 (2) ◽  
pp. 243-252 ◽  
Author(s):  
Chuan Wang ◽  
Yi Mao ◽  
Jia Yu ◽  
Lin Zhu ◽  
Ming Li ◽  
...  
Keyword(s):  
Inorganic Phosphate ◽  
Stress Conditions ◽  
Nutrient Deprivation ◽  
Pho Regulon ◽  
Metabolic Homeostasis ◽  
Content Type ◽  
Redox States ◽  
Nadh Ratio ◽  
Increased Sensitivity

ABSTRACTThe ability of pathogenic mycobacteria to adapt to diverse environments is essential for their success as pathogens. Here we describe a transposon-inactivatedphoY2mutant ofMycobacterium marinum. PhoY2 of mycobacteria is a functional homologue of PhoU inEscherichia coliand an important component of the Pho regulon. We found that PhoY2 is required for maintaining intracellular inorganic phosphate (Pi) homeostasis and balanced energy and redox states. Disruption ofphoY2resulted in elevated levels of intracellular poly-Piand ATP and an elevated NAD+/NADH ratio, and the mutant strain exhibited increased sensitivity to environmental stress conditions, including nutrient deprivation as well as SDS and antibiotic treatments. Taken together, our results suggest that PhoY2 is required for maintaining metabolic homeostasis and adaptation to stress conditions, which may provide an explanation for the suggested role of PhoY2 in drug tolerance.

scholarly journals Lon Protease Is Important for Growth under Stressful Conditions and Pathogenicity of the Phytopathogen, Bacterium Dickeya solani

2020 ◽  
Vol 21 (10) ◽  
pp. 3687
Author(s):  
Donata Figaj ◽  
Paulina Czaplewska ◽  
Tomasz Przepióra ◽  
Patrycja Ambroziak ◽  
Marta Potrykus ◽  
...  
Keyword(s):  
Pathogenic Bacteria ◽  
Plant Pathogens ◽  
Stress Conditions ◽  
Lon Protease ◽  
Theoretical Mass ◽  
Pectinolytic Enzymes ◽  
Response To Stress ◽  
Increased Sensitivity ◽  
Dickeya Solani

The Lon protein is a protease implicated in the virulence of many pathogenic bacteria, including some plant pathogens. However, little is known about the role of Lon in bacteria from genus Dickeya. This group of bacteria includes important potato pathogens, with the most aggressive species, D. solani. To determine the importance of Lon for pathogenicity and response to stress conditions of bacteria, we constructed a D. solani Δlon strain. The mutant bacteria showed increased sensitivity to certain stress conditions, in particular osmotic and high-temperature stresses. Furthermore, qPCR analysis showed an increased expression of the lon gene in D. solani under these conditions. The deletion of the lon gene resulted in decreased motility, lower activity of secreted pectinolytic enzymes and finally delayed onset of blackleg symptoms in the potato plants. In the Δlon cells, the altered levels of several proteins, including virulence factors and proteins associated with virulence, were detected by means of Sequential Window Acquisition of All Theoretical Mass Spectra (SWATH-MS) analysis. These included components of the type III secretion system and proteins involved in bacterial motility. Our results indicate that Lon protease is important for D. solani to withstand stressful conditions and effectively invade the potato plant.

scholarly journals Functional Analysis of the Exocyst Subunit Sec15 in Candida albicans

2015 ◽  
Vol 14 (12) ◽  
pp. 1228-1239 ◽  
Author(s):  
Alba A. Chavez-Dozal ◽  
Stella M. Bernardo ◽  
Hallie S. Rane ◽  
Samuel A. Lee
Keyword(s):  
Candida Albicans ◽  
Gene Repression ◽  
Content Type ◽  
Polarized Secretion ◽  
Conditional Mutant ◽  
Direct Contrast ◽  
Increased Sensitivity ◽  
Gfp Marking ◽  
Time Point

ABSTRACTIn prior studies of exocyst-mediated late secretion inCandida albicans, we have determined that Sec6 contributes to cell wall integrity, secretion, and filamentation. A conditional mutant lackingSEC6expression exhibits markedly reduced lateral hyphal branching. In addition, lack of the related t-SNAREs Sso2 and Sec9 also leads to defects in secretion and filamentation. To further understand the role of the exocyst in the fundamental processes of polarized secretion and filamentation inC. albicans, we studied the exocyst subunit Sec15. SinceSaccharomyces cerevisiae SEC15is essential for viability, we generated aC. albicansconditional mutant strain in whichSEC15was placed under the control of a tetracycline-regulated promoter. In the repressed state, cell death occurred after 5 h in the tetR-SEC15 strain. Prior to this time point, the tetR-SEC15 mutant was markedly defective in Sap and lipase secretion and demonstrated increased sensitivity to Zymolyase and chitinase. Notably, tetR-SEC15 mutant hyphae were characterized by a hyperbranching phenotype, in direct contrast to strain tetR-SEC6, which had minimal lateral branching. We further studied the localization of the Spitzenkörper, polarisomes, and exocysts in the tetR-SEC15 and tetR-SEC6 mutants during filamentation. Mlc1-GFP (marking the Spitzenkörper), Spa2-GFP (the polarisome), and Exo70-GFP (exocyst) localizations were normal in the tetR-SEC6 mutant, whereas these structures were mislocalized in the tetR-SEC15 mutant. Following alleviation of gene repression by removing doxycycline, first Spitzenkörper, then polarisome, and finally exocyst localizations were recovered sequentially. These results indicate that the exocyst subunits Sec15 and Sec6 have distinct roles in mediating polarized secretion and filamentation inC. albicans.

scholarly journals Phenotypic Characterization of acopAMutant of Neisseria gonorrhoeae Identifies a Link between Copper and Nitrosative Stress

2011 ◽  
Vol 80 (3) ◽  
pp. 1065-1071 ◽  
Author(s):  
Karrera Y. Djoko ◽  
Jessica A. Franiek ◽  
Jennifer L. Edwards ◽  
Megan L. Falsetta ◽  
Stephen P. Kidd ◽  
...  
Keyword(s):  
Neisseria Gonorrhoeae ◽  
Nitrosative Stress ◽  
Efflux Pump ◽  
Copper Ions ◽  
Copper Ion ◽  
Phenotypic Characterization ◽  
Wild Type ◽  
Content Type ◽  
Increased Sensitivity

NGO0579 is annotatedcopAin theNeisseria gonorrhoeaechromosome, suggesting that it encodes a cation-transporting ATPase specific for copper ions. Compared to wild-type cells, acopAmutant was more sensitive to killing by copper ions but not to other transition metals. The mutant also accumulated a greater amount of copper, consistent with the predicted role of CopA as a copper efflux pump. ThecopAmutant showed a reduced ability to invade and survive within human cervical epithelial cells, although its ability to form a biofilm on the surface of these cells was not significantly different from that of the wild type. In the presence of copper, thecopAmutant exhibited increased sensitivity to killing by nitrite or nitric oxide. Therefore, we concluded that copper ion efflux catalyzed by CopA is linked to the nitrosative stress defense system ofNeisseria gonorrhoeae. These observations suggest that copper may exert its effects as an antibacterial agent in the innate immune system via an interaction with reactive nitrogen species.

Long-term management of patients with multiple brain metastases after shaped beam radiosurgery

2004 ◽  
pp. 406-412
Author(s):  
Paul Okunieff ◽  
Michael C. Schell ◽  
Russell Ruo ◽  
E. Ronald Hale ◽  
Walter G. O'Dell ◽  
...  
Keyword(s):  
Brain Metastases ◽  
Tumor Control ◽  
Content Type ◽  
Negative Results ◽  
Multiple Metastases ◽  
Extracranial Disease ◽  
Successful Control ◽  
The Brain

✓ The role of radiosurgery in the treatment of patients with advanced-stage metastatic disease is currently under debate. Previous randomized studies have not consistently supported the use of radiosurgery to treat patients with numbers of brain metastases. In negative-results studies, however, intracranial tumor control was high but extracranial disease progressed; thus, patient survival was not greatly affected, although neurocognitive function was generally maintained until death. Because the future promises improved systemic (extracranial) therapy, the successful control of brain disease is that much more crucial. Thus, for selected patients with multiple metastases to the brain who remain in good neurological condition, aggressive lesion-targeting radiosurgery should be very useful. Although a major limitation to success of this therapy is the lack of control of extracranial disease in most patients, it is clear that well-designed, aggressive treatment substantially decreases the progression of brain metastases and also improves neurocognitive survival. The authors present the management and a methodology for rational treatment of a patient with breast cancer who has harbored 24 brain metastases during a 3-year period.

scholarly journals Vulnerable adults in police custody

2019 ◽  
Vol 22 (1) ◽  
pp. 5-8
Author(s):  
Ian Cummins
Keyword(s):  
Design Methodology ◽  
Research Literature ◽  
Police Custody ◽  
England And Wales ◽  
Content Type ◽  
Increased Risk ◽  
Vulnerable Adults

Purpose The purpose of this paper is to discuss the recent National Appropriate Adult Network (NAAN) report on the role of the appropriate adult. Design/methodology/approach This paper is based on the NAAN report and a review of relevant policy and research literature. Findings There to Help 2 highlights that there are still significant gaps in the provision of appropriate adult schemes across England and Wales. These gaps potentially place vulnerable adults at increased risk. Originality/value This paper is a review of recent research.

Financial access and economic development: the moderating role of financial consumer protection

2019 ◽  
Vol 15 (4) ◽  
pp. 406-424 ◽  
Author(s):  
Maryam Kriese ◽  
Joshua Yindenaba Abor ◽  
Elikplimi Agbloyor
Keyword(s):  
Economic Development ◽  
World Bank ◽  
Financial Literacy ◽  
Compliance Monitoring ◽  
Financial Access ◽  
Policy Makers ◽  
Content Type ◽  
The World Bank ◽  
Moderating Role

Purpose The purpose of this paper is to examine the moderating role of financial consumer protection (FCP) in the access–development nexus. Design/methodology/approach The study is based on cross-country data on 102 countries surveyed in the World Bank Global Survey on FCP and Financial Literacy (2013). The White heteroscedasticity adjusted regressions and Two-stage least squares regressions (2SLS) are used for the estimation. Findings Interactions between FCP regulations that foster fair treatment, disclosure, dispute resolution and recourse and financial access have positive net effects on economic development. However, there is no sufficient evidence to suggest that interactions between financial access and enforcement and compliance monitoring regulations have a significant effect on economic development. Practical implications First, policy makers should continue with efforts aimed at instituting FCP regimes as part of strategies aimed at broadening access to financial services for enhanced economic development. Second, instituting FCP regimes per se may not be enough. Policy makers need to consider possible intervening factors such as the provision of adequate resources and supervisory authority, for compliance monitoring and enforcement to achieve the expected positive effect on economic development. Originality/value This study extends evidence in the law–finance–growth literature by providing empirical evidence on the effect of legal institution specific to the protection of retail financial consumers on the access–development nexus using a nouvel data set, the World Bank Global survey on FCP and Financial Literacy (2013).

Categorization flexibility and unconventional choices: is life an adventure?

2020 ◽  
Vol 54 (8) ◽  
pp. 1963-1986
Author(s):  
Tilottama G. Chowdhury ◽  
Feisal Murshed
Keyword(s):  
Interactive Effect ◽  
Interactive Effects ◽  
Cognitive Capacity ◽  
Purchase Behavior ◽  
Consumer Decision Making ◽  
Cross Sectional ◽  
Content Type ◽  
Cross Domain ◽  
Multiple Domains

Purpose This paper proposes that categorization flexibility, operationalized as the cognitive capacity that cross-categorizes products in multiple situational categories across multiple domains, might favorably influence a consumer’s evaluation of unconventional options. Design/methodology/approach Experimental research design is used to test the theory. An exploratory study first establishes the effect of categorization flexibility in a non-food domain. Study 1 documents the moderating role of decision domain, showing that the effect works only under low- (vs high-) consequence domain. Studies 2A and 2B further refine the notion by showing that individuals can be primed in a relatively higher categorization flexibility frame of mind. Study 3 demonstrates the interactive effect of categorization flexibility and adventure priming in a high-consequence domain. Study 4 integrates the interactive effects of decisions with low- vs high-consequence, adventure priming and categorization flexibility within a single decision domain of high consequence. Findings Consumers with higher- (vs lower-) categorization flexibility tend to opt for unconventional choices when the decision domain entails low consequences, whereas such a result does not hold under decision domain of high consequences. The categorization flexibility effects in case of low-consequence decision domain holds true even when consumers are primed to be categorization flexible. Furthermore, with additional adventure priming, consumers show an increased preference for unconventional options even under a decision domain with high consequence. Research limitations/implications This study could not examine real purchase behavior as results are based on cross-sectional, behavioral intention data. In addition, it did not examine the underlying reason for presence of cross-domain categorization flexibility index. Practical implications The results suggest that stimuli may be tailored to consumers in ways that increase the salience and the perceived attractiveness of unconventional choices. Further, data reinforce the notion of cross-categorical interrelations among different domains, which could be leveraged by marketers. Originality/value This study represents the first documentation of the potential ways by which unconventional product choice might be a function of individuals’ categorization flexibility level across different types of decision domains. The findings yield implications that are novel to both categorization and consumer decision-making literature.

The path of support-to-sales: mediating role of seller collaborative information exchange in social commerce

2020 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Li Chen ◽  
Fengxia Zhu ◽  
Murali Mantrala
Keyword(s):  
Information Exchange ◽  
Instrumental Support ◽  
Trade Volume ◽  
Social Commerce ◽  
Content Type ◽  
Mediating Role ◽  
The Social ◽  
Source Data ◽  
Negative Effect

Purpose This paper aims to systematically investigate the direct and indirect effects of four types of support – peer instrumental support, peer emotional support, platform business support and platform communication support – on seller trade volume in social commerce. It also aims to uncover the path of support-to-sales of the seller from a platform perspective and provides a more complete picture of the social commerce phenomenon. Design/methodology/approach This paper uses multi-source data including primary survey data and secondary data on trade volume to test the hypotheses. PROCESS mediation model is used to analyze the multi-source data set. Findings This study finds that the positive effects of peer instrumental support, platform business support and platform communication support on seller trade volume are fully mediated by seller collaborative information exchange. Also, peer emotional support has a significant negative effect on seller trade volume and collaborative information exchange can serve as a buffer to mitigate the negative effect. Research limitations/implications The authors provide new insights into what types of support are or are not conducive to improving transaction volume of individual sellers and highlight the mediating role of seller information exchange in this value generation process in social commerce. These findings advance current knowledge of how seller interactions increase value in social commerce. The chosen research setting may limit the generalizability of the findings of this study. Practical implications This paper offers valuable implications for social commerce platforms on how to better serve their sellers to achieve high growth. Specifically, the findings suggest that platforms should encourage instrumental support and information exchange among peer sellers. In addition, platforms should expand seller support from a single-focus on sellers’ business to a dual-focus on both sellers’ business and socialization in social commerce. Originality/value This paper fulfills an identified need to study how sellers can better derive value from the social interactions and how social commerce platforms can effectively influence transactions, support sales and serve as a selling platform.

The effect of psychological empowerment on job burnout and competitive advantage

2020 ◽  
Vol 18 (1) ◽  
pp. 47-71 ◽  
Author(s):  
Ali Safari ◽  
Arash Adelpanah ◽  
Razieh Soleimani ◽  
Parisa Heidari Aqagoli ◽  
Rosa Eidizadeh ◽  
...  
Keyword(s):  
Data Analysis ◽  
Organizational Commitment ◽  
Competitive Advantage ◽  
Indirect Effect ◽  
Psychological Empowerment ◽  
Job Burnout ◽  
Equation Modeling ◽  
Content Type ◽  
Mediating Role

Purpose This study aims at investigating the effect of psychological empowerment on job burnout and competitive advantage with the mediating role of organizational commitment and creativity. Design/methodology/approach The statistical population included all the managers and staffs of Tooka Company in Iran, and for data analysis, 120 completed questionnaires were used. Data analysis was carried out by SPSS 18 and Amos 20 software and structural equation modeling method. To test the mediating relationships, bootstrap method was used. Findings The findings showed that psychological empowerment has a significant direct effect on job burnout and competitive advantage. Also, psychological empowerment has a significant indirect effect on job burnout through the mediating role of organizational commitment. In addition, psychological empowerment has a significant indirect effect on competitive advantage through the mediating role of organizational creativity. Originality/value This study is among the first to investigate the relationship between psychological empowerment, job burnout, competitive advantage, organizational commitment and creativity.

Role of burnout on job level, job satisfaction, and task performance

2017 ◽  
Vol 38 (5) ◽  
pp. 630-645 ◽  
Author(s):  
Won Ho Kim ◽  
Young-An Ra ◽  
Jong Gyu Park ◽  
Bora Kwon
Keyword(s):  
Job Satisfaction ◽  
Task Performance ◽  
Organizational Context ◽  
Content Type ◽  
Job Level ◽  
Mediating Role ◽  
Final Sample ◽  
The Relationship ◽  
And Task

Purpose The purpose of this paper is to examine the mediating role of burnout (i.e. exhaustion, cynicism, professional inefficacy) in the relationship between job level and job satisfaction as well as between job level and task performance. Design/methodology/approach The final sample included 342 Korean workers from selected companies. The authors employed the Hayes (2013) PROCESS tool for analyzing the data. Findings The results showed that all three subscales of burnout (i.e. exhaustion, cynicism, professional inefficacy) mediate the relationship between job level and job satisfaction. However, only two mediators (i.e. cynicism, professional inefficacy) indicated the mediating effects on the association between job level and task performance. Originality/value This research presented the role of burnout on the relationships between job level, job satisfaction, and task performance especially in South Korean organizational context. In addition to role of burnout, findings should prove helpful in improving job satisfaction and task performance. The authors provide implications and limitations of the findings.

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