Glycosphingolipids Recognized by Acinetobacter baumannii

Acinetobacter baumannii is an opportunistic bacterial pathogen associated with hospital-acquired infections, including pneumonia, meningitis, bacteremia, urinary tract infection, and wound infections. Recognition of host cell surface carbohydrates plays a crucial role in adhesion and enables microbes to colonize different host niches. Here the potential glycosphingolipid receptors of A. baumannii were examined by binding of S-35-labeled bacteria to glycosphingolipids on thin-layer chromatograms. Thereby a selective interaction with two non-acid glycosphingolipids of human and rabbit small intestine was found. The binding-active glycosphingolipids were isolated and, on the basis of mass spectrometry, identified as neolactotetraosylceramide (Gal beta 4GlcNAc beta 3Gal beta 4Glc beta 1Cer) and lactotetraosylceramide (Gal beta 3GlcNAc beta 3Gal beta 4Glc beta 1Cer). Further binding assays using reference glycosphingolipids showed that A. baumannii also bound to lactotriaosylceramide (GlcNAc beta 3Gal beta 4Glc beta 1Cer) demonstrating that GlcNAc was the basic element recognized. In addition, the bacteria occasionally bound to galactosylceramide, lactosylceramide with phytosphingosine and/or hydroxy fatty acids, isoglobotriaosylceramide, gangliotriaosylceramide, and gangliotetraosylceramide, in analogy with binding patterns that previously have been described for other bacteria classified as "lactosylceramide-binding". Finally, by isolation and characterization of glycosphingolipids from human skin, the presence of neolactotetraosylceramide was demonstrated in this A. baumannii target tissue

Structural basis for Acinetobacter baumannii biofilm formation

Acinetobacter baumannii-a leading cause of nosocomial infections-has a remarkable capacity to persist in hospital environments and medical devices due to its ability to form biofilms. Biofilm formation is mediated by Csu pili, assembled via the "archaic" chaperone-usher pathway. The X-ray structure of the CsuC-CsuE chaperone-adhesin preassembly complex reveals the basis for bacterial attachment to abiotic surfaces. CsuE exposes three hydrophobic finger-like loops at the tip of the pilus. Decreasing the hydrophobicity of these abolishes bacterial attachment, suggesting that archaic pili use tip-fingers to detect and bind to hydrophobic cavities in substrates. Antitip antibody completely blocks biofilm formation, presenting a means to prevent the spread of the pathogen. The use of hydrophilic materials instead of hydrophobic plastics in medical devices may represent another simple and cheap solution to reduce pathogen spread. Phylogenetic analysis suggests that the tip-fingers binding mechanism is shared by all archaic pili carrying two-domain adhesins. The use of flexible fingers instead of classical receptor-binding cavities is presumably more advantageous for attachment to structurally variable substrates, such as abiotic surfaces

The impact of society on management control systems

© 2017 Elsevier Ltd The aim of this study is to investigate whether certain configurations of management controls dominate in certain societies (socio-cultural contexts) and whether the effectiveness of a given archetype of management control systems (MCSs) varies depending on the socio-cultural setting—the society—in which it operates. The study focuses on three socio-cultural groups and the corresponding institutional contexts (an Anglo-Saxon group, a Central European group, and a Northern European group) and three MCS archetypes (delegated bureaucratic control, delegated output control, and programmable output control). We use unique data from a cross-national, interview-based survey encompassing 610 strategic business units from nine countries (seven European countries plus Canada and Australia). The idea that firms tend to adapt MCSs to the socio-cultural context does not gain empirical support in this study. No significant differences in the distribution of MCSs between the three socio-cultural groups are noted. However, we do find that programmable output control has a more positive impact on effectiveness in Anglo-Saxon cultures, while delegated output control has a more positive impact on effectiveness in Northern Europe. Taken together these findings indicate that distinct differences between societies make a particular MCS design more appropriate in a given society, but where such differences are not dramatic (as in the present case), multiple MCS designs can be found in the same society

How combinations of control elements create tensions and how these can be managed:An embedded case study

This paper explores how combinations of management control (MC) elements can create tensions, and what supervisors can do to manage these tensions. We extend the literature on the interplay of MC elements by examining the underlying micro-processes that give rise to tensions between MC elements. Specifically, drawing on both the MC and the organization literature, we investigate how interactions between MC elements can simultaneously enhance and diminish control effectiveness, for which we coin the term tension complexity, and how these tensions can change over time, which we label tension dynamics. We empirically inform our study with an embedded case study in a public sector organization in the Netherlands. Using interviews, desk research, and observations, this study specifically investigates how an organization-level MC element (the value 'self-management') relates to departmental MC elements, creating tensions. The findings highlight that tensions, because of their dynamic and complex nature, require continuous attention from managers. Furthermore, the case findings demonstrate how department managers can influence the tensions by affecting the balance, balance tendency, and intensity of the MC elements within them. We conclude by providing suggestions for further research into the interactions of MC elements

The multiplicity of performance management systems:Heterogeneity in multinational corporations and management sense-making

This field study examines the workings of multiple performance measurement systems (PMSs) used within and between a division and Headquarters (HQ) of a large European corporation. We explore how multiple PMSs arose within the multinational corporation. We first provide a first‐order analysis which explains how managers make sense of the multiplicity and show how an organization's PMSs may be subject to competing processes for control that result in varied systems, all seemingly functioning, but with different rationales and effects. We then provide a second‐order analysis based on a sense‐making perspective that highlights the importance of retrospective understandings of the organization's history and the importance of various legitimacy expectations to different parts of the multinational. Finally, we emphasize the role of social skill in sense‐making that enables the persistence of multiple systems and the absence of overt tensions and conflict within organizations

Glycosphingolipids Recognized by Acinetobacter baumannii

Acinetobacter baumannii is an opportunistic bacterial pathogen associated with hospital-acquired infections, including pneumonia, meningitis, bacteremia, urinary tract infection, and wound infections. Recognition of host cell surface carbohydrates plays a crucial role in adhesion and enables microbes to colonize different host niches. Here the potential glycosphingolipid receptors of A. baumannii were examined by binding of 35S-labeled bacteria to glycosphingolipids on thin-layer chromatograms. Thereby a selective interaction with two non-acid glycosphingolipids of human and rabbit small intestine was found. The binding-active glycosphingolipids were isolated and, on the basis of mass spectrometry, identified as neolactotetraosylceramide (Galβ4GlcNAcβ3Galβ4Glcβ1Cer) and lactotetraosylceramide (Galβ3GlcNAcβ3Galβ4Glcβ1Cer). Further binding assays using reference glycosphingolipids showed that A. baumannii also bound to lactotriaosylceramide (GlcNAcβ3Galβ4Glcβ1Cer) demonstrating that GlcNAc was the basic element recognized. In addition, the bacteria occasionally bound to galactosylceramide, lactosylceramide with phytosphingosine and/or hydroxy fatty acids, isoglobotriaosylceramide, gangliotriaosylceramide, and gangliotetraosylceramide, in analogy with binding patterns that previously have been described for other bacteria classified as “lactosylceramide-binding”. Finally, by isolation and characterization of glycosphingolipids from human skin, the presence of neolactotetraosylceramide was demonstrated in this A. baumannii target tissue

Structural basis for Acinetobacter baumannii biofilm formation

Acinetobacter baumannii-a leading cause of nosocomial infections-has a remarkable capacity to persist in hospital environments and medical devices due to its ability to form biofilms. Biofilm formation is mediated by Csu pili, assembled via the "archaic" chaperone-usher pathway. The X-ray structure of the CsuC-CsuE chaperone-adhesin preassembly complex reveals the basis for bacterial attachment to abiotic surfaces. CsuE exposes three hydrophobic finger-like loops at the tip of the pilus. Decreasing the hydrophobicity of these abolishes bacterial attachment, suggesting that archaic pili use tip-fingers to detect and bind to hydrophobic cavities in substrates. Antitip antibody completely blocks biofilm formation, presenting a means to prevent the spread of the pathogen. The use of hydrophilic materials instead of hydrophobic plastics in medical devices may represent another simple and cheap solution to reduce pathogen spread. Phylogenetic analysis suggests that the tip-fingers binding mechanism is shared by all archaic pili carrying two-domain adhesins. The use of flexible fingers instead of classical receptor-binding cavities is presumably more advantageous for attachment to structurally variable substrates, such as abiotic surfaces