Genome Stability of Lyme Disease Spirochetes: Comparative Genomics of Borrelia burgdorferi Plasmids

Lyme disease is the most common tick-borne human illness in North America. In order to understand the molecular pathogenesis, natural diversity, population structure and epizootic spread of the North American Lyme agent, Borrelia burgdorferi sensu stricto, a much better understanding of the natural diversity of its genome will be required. Towards this end we present a comparative analysis of the nucleotide sequences of the numerous plasmids of B. burgdorferi isolates B31, N40, JD1 and 297. These strains were chosen because they include the three most commonly studied laboratory strains, and because they represent different major genetic lineages and so are informative regarding the genetic diversity and evolution of this organism. A unique feature of Borrelia genomes is that they carry a large number of linear and circular plasmids, and this work shows that strains N40, JD1, 297 and B31 carry related but non-identical sets of 16, 20, 19 and 21 plasmids, respectively, that comprise 33–40% of their genomes. We deduce that there are at least 28 plasmid compatibility types among the four strains. The B. burgdorferi ∼900 Kbp linear chromosomes are evolutionarily exceptionally stable, except for a short ≤20 Kbp plasmid-like section at the right end. A few of the plasmids, including the linear lp54 and circular cp26, are also very stable. We show here that the other plasmids, especially the linear ones, are considerably more variable. Nearly all of the linear plasmids have undergone one or more substantial inter-plasmid rearrangements since their last common ancestor. In spite of these rearrangements and differences in plasmid contents, the overall gene complement of the different isolates has remained relatively constant

When Leaders and Followers Match: The Impact of Objective Value Congruence, Value Extremity, and Empowerment on Employee Commitment and Job Satisfaction

Although the topic of value congruence has attracted considerable attention from researchers and practitioners, evidence for the link between person–supervisor value congruence and followers’ reactions is less robust than often assumed. This study addresses three central issues in our understanding of person–supervisor value congruence (a) by assessing the impact of objective person–supervisor value congruence rather than subjective value congruence, (b) by examining the differential effects of value congruence in strongly versus moderately held values, and (c) by exploring perceived empowerment as a central mediating mechanism. Results of a multi-source study comprising 116 person–supervisor dyads reveal that objective value congruence relates to followers’ job satisfaction and affective commitment and that this link can be explained by followers’ perceived empowerment. Moreover, polynomial regression and response surface analyses reveal that congruence effects vary with the importance that leaders and followers ascribe to a certain value: Congruency in strongly held values have more robust relations with followers’ outcomes than congruence in moderately held values

The relationship between employees' objective internal and external pay standing and their job performance: A within-person analysis

Purpose: Researchers have paid little attention to the relationship between employees’ objective internal and external pay standing and their job performance. Moreover, few studies have considered that employees’ objective pay standing is dynamic; that is, it changes over time. In this study, we analyze the relationship between changes in employees’ objective internal and external pay standing and their job performance. Design/Methodology/Approach: We test the hypotheses using data for players in the National Basketball Association over a period of 12 seasons (n = 4830). Findings. Decreases in employees’ objective internal and external pay standing are negatively related to their task performance. Furthermore, decreases in employees’ objective internal pay standing, but not in their external pay standing, are negatively related to their contextual performance. Implications. Analyzing the relationship between changes in employees’ objective internal and external pay standing and their job performance adds to our understanding of the individual-level consequences of pay dispersion. Originality/Value. This is one of the first studies to analyze the relationship between employees’ objective internal and external pay standing and their job performance. Moreover, this is one of the first studies that considers that employees’ objective internal and external pay standing changes, for example, because the external and internal labor markets change. The study contributes to research on employee compensation and salary, and to research on pay disparities