801 research outputs found
Development of a D-xylose fermenting and inhibitor tolerant industrial Saccharomyces cerevisiae strain with high performance in lignocellulose hydrolysates using metabolic and evolutionary engineering
Background: The production of bioethanol from lignocellulose hydrolysates requires a robust, D-xylose-fermenting and inhibitor-tolerant microorganism as catalyst. The purpose of the present work was to develop such a strain from a prime industrial yeast strain, Ethanol Red, used for bioethanol production.
Results: An expression cassette containing 13 genes including Clostridium phytofermentans XylA, encoding D-xylose isomerase (XI), and enzymes of the pentose phosphate pathway was inserted in two copies in the genome of Ethanol Red. Subsequent EMS mutagenesis, genome shuffling and selection in D-xylose-enriched lignocellulose hydrolysate, followed by multiple rounds of evolutionary engineering in complex medium with D-xylose, gradually established efficient D-xylose fermentation. The best-performing strain, GS1.11-26, showed a maximum specific D-xylose consumption rate of 1.1 g/g DW/h in synthetic medium, with complete attenuation of 35 g/L D-xylose in about 17 h. In separate hydrolysis and fermentation of lignocellulose hydrolysates of Arundo donax (giant reed), spruce and a wheat straw/hay mixture, the maximum specific D-xylose consumption rate was 0.36, 0.23 and 1.1 g/g DW inoculum/h, and the final ethanol titer was 4.2, 3.9 and 5.8% (v/v), respectively. In simultaneous saccharification and fermentation of Arundo hydrolysate, GS1.11-26 produced 32% more ethanol than the parent strain Ethanol Red, due to efficient D-xylose utilization. The high D-xylose fermentation capacity was stable after extended growth in glucose. Cell extracts of strain GS1.11-26 displayed 17-fold higher XI activity compared to the parent strain, but overexpression of XI alone was not enough to establish D-xylose fermentation. The high D-xylose consumption rate was due to synergistic interaction between the high XI activity and one or more mutations in the genome. The GS1.11-26 had a partial respiratory defect causing a reduced aerobic growth rate.
Conclusions: An industrial yeast strain for bioethanol production with lignocellulose hydrolysates has been developed in the genetic background of a strain widely used for commercial bioethanol production. The strain uses glucose and D-xylose with high consumption rates and partial cofermentation in various lignocellulose hydrolysates with very high ethanol yield. The GS1.11-26 strain shows highly promising potential for further development of an all-round robust yeast strain for efficient fermentation of various lignocellulose hydrolysates
A revised generic classification of the tribe Sileneae (Caryophyllaceae)
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73198/1/j.1756-1051.2000.tb00760.x.pd
The circumstances of migrant families raising children with disabilities in five European countries: Updating knowledge and pursuing new research
In 2017, specialists in several fields (health, education, and social work) from five European countries (France, Georgia, Italy, Norway, and Switzerland) established a network to jointly pursue studies on migration and disability. An initial workshop provided an opportunity to discuss their previous individual work and to develop a comparative research project. This article presents the key aspects of the discussion and the resulting plans for collaborative study. First, migrant children with disabilities remain statistically invisible in some countries. Separate policies and systems address their needs as migrants and their needs as persons with disabilities. Second, in all countries covered by the research network, there is an important gap between legal norms and the circumstances of migrant families raising children with disabilities. The same holds true for collaboration between public agencies, or between those agencies and NGOs (serving persons with disabilities, migrants, and/or national minorities). Further comparative and cross-disciplinary study must focus on increasing the social participation of children with disabilities and their families through social, educational, and health interventions within an intercultural context
Willing and able: action-state orientation and the relation between procedural justice and employee cooperation
Existing justice theory explains why fair procedures motivate employees to adopt cooperative goals, but it fails to explain how employees strive towards these goals. We study self-regulatory abilities that underlie goal striving; abilities that should thus affect employees’ display of cooperative behavior in response to procedural justice. Building on action control theory, we argue that employees who display effective self-regulatory strategies (action oriented employees) display relatively strong cooperative behavioral responses to fair procedures. A multisource field study and a laboratory experiment support this prediction. A subsequent experiment addresses the process underlying this effect by explicitly showing that action orientation facilitates attainment of the cooperative goals that people adopt in response to fair procedures, thus facilitating the display of actual cooperative behavior. This goal striving approach better integrates research on the relationship between procedural justice and employee cooperation in the self-regulation and the work motivation literature. It also offers organizations a new perspective on making procedural justice effective in stimulating employee cooperation by suggesting factors that help employees reach their adopted goals
Abusive supervision and employee deviance : a multifoci justice perspective
In order to address the influence of unethical leader behaviors in the form of abusive supervision on subordinates’ retaliatory responses, we meta-analytically examined the impact of abusive supervision on subordinate deviance, inclusive of the role of justice and power distance. Specifically, we investigated the mediating role of supervisory- and organizationally focused justice and the moderating role of power distance as one model explaining why and when abusive supervision is related to subordinate deviance toward supervisors and organizations. With 79 independent sample studies (N = 22,021), we found that abusive supervision was more strongly related to supervisory-focused justice, compared to organizationally focused justice perceptions, and both types of justice perceptions were related to target-similar deviance (deviance toward the supervisor and organization, respectively). Finally, our results showed that the negative implications of abusive supervision were stronger in lower power distance cultures compared to higher power distance cultures.http://link.springer.com/journal/105512020-09-20hj2020Human Resource Managemen
The Importance of Being Psychologically Empowered: Buffering the Negative Effects of Employee Perceptions of Leader-Member Exchange Differentiation
Although differentiated relationships among leaders and their followers are fundamental to Leader-Member Exchange (LMX) theory, research provides limited knowledge about whether employees’ responses to individual perceptions of LMX differentiation are uniform. In a field study, we examined whether individual-level psychological empowerment buffers the negative relationship between perceived LMX differentiation and job satisfaction, and found that the negative relationship is strongest under low employee psychological empowerment conditions, as compared to high psychological empowerment. Furthermore, in a multi-wave field study and an experiment, we extended these initial findings by investigating employees’ perceptions of supervisory fairness as a mediator of this moderated relationship. We found that the indirect effect between perceived LMX differentiation and job satisfaction, through supervisory fairness perceptions, is strongest under low employee psychological empowerment, as compared to high psychological empowerment. Collectively, our findings showcase the importance of psychological empowerment as a tool for employees to use to counteract the negative effect of perceived differentiated contexts
Understanding Face and Shame: A Servant-Leadership and Face Management Model
Clergy can have a negative impact on churches and other individuals when they knowingly or unknowingly attempt to save face, that is, try to protect their standing or reputation. The desire to gain face and the fear of losing face and feeling ashamed will likely permeate clergy’s decision-making processes without even being noticed. This study explores the essence of face and face management and the relationship between face management and two characteristics of servant-leadership—awareness and healing—in both Chinese and American churches through the methodology of hermeneutic phenomenology. Prior to this study, to my knowledge, no hermeneutic phenomenological research of face management has been conducted in a church setting. Through a review of the literature, four areas are explored: face and shame, face management, servant-leadership, and face, shame, and face management within the church. This study obtained approval from the Institutional Review Board and informed consent from the participants. Three Chinese and three American Christian ministers were chosen to complete a question sheet and participate in two semi-structured interview sessions. A first cycle of open coding and second cycle of pattern coding were used during data analysis. Face experiences are discussed in light of eight major themes: body, triggers, becoming, face concepts, strategies, emotions, servant-leadership, and the church. Findings from the study help build a servant-leadership and face management model, which can offer an anchored approach for clergy and pastoral counselors to address face and shame and to develop therapeutic interventions
THE ROLE OF INTERDEPENDENCE IN THE MICRO-FOUNDATIONS OF ORGANIZATION DESIGN: TASK, GOAL, AND KNOWLEDGE INTERDEPENDENCE
Interdependence is a core concept in organization design, yet one that has remained consistently understudied. Current notions of interdependence remain rooted in seminal works, produced at a time when managers’ near-perfect understanding of the task at hand drove the organization design process. In this context, task interdependence was rightly assumed to be exogenously determined by characteristics of the work and the technology. We no longer live in that world, yet our view of interdependence has remained exceedingly task-centric and our treatment of interdependence overly deterministic. As organizations face increasingly unpredictable workstreams and workers co-design the organization alongside managers, our field requires a more comprehensive toolbox that incorporates aspects of agent-based interdependence. In this paper, we synthesize research in organization design, organizational behavior, and other related literatures to examine three types of interdependence that characterize organizations’ workflows: task, goal, and knowledge interdependence. We offer clear definitions for each construct, analyze how each arises endogenously in the design process, explore their interrelations, and pose questions to guide future research
Predicting Global Fund grant disbursements for procurement of artemisinin-based combination therapies
Does culture matter? The effects of acculturation on workplace relationships
In spite of immigrants’ growing role in the workforce of the United States and other developed countries, organizational communication research about the experience of immigrant employees in the host culture is still very limited. Drawing on the bidimensional acculturation theory, the purpose of this study was to investigate the association of acculturation of immigrant employees with three types of workplace relationships: leader–member exchange (LMX), coworker, and mentoring relationship. Based on a survey of immigrant employees in a U.S. Midwestern city, the study reveals that the two dimensions of acculturation, adjustment to one’s host culture and retention of one’s original culture, are differentially related to the three types of workplace relationships. Both theoretical and practical implications of these findings are discussed in the study
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