Identification of a General O-linked Protein Glycosylation System in Acinetobacter baumannii and Its Role in Virulence and Biofilm Formation

Acinetobacter baumannii is an emerging cause of nosocomial infections. The isolation of strains resistant to multiple antibiotics is increasing at alarming rates. Although A. baumannii is considered as one of the more threatening “superbugs” for our healthcare system, little is known about the factors contributing to its pathogenesis. In this work we show that A. baumannii ATCC 17978 possesses an O-glycosylation system responsible for the glycosylation of multiple proteins. 2D-DIGE and mass spectrometry methods identified seven A. baumannii glycoproteins, of yet unknown function. The glycan structure was determined using a combination of MS and NMR techniques and consists of a branched pentasaccharide containing N-acetylgalactosamine, glucose, galactose, N-acetylglucosamine, and a derivative of glucuronic acid. A glycosylation deficient strain was generated by homologous recombination. This strain did not show any growth defects, but exhibited a severely diminished capacity to generate biofilms. Disruption of the glycosylation machinery also resulted in reduced virulence in two infection models, the amoebae Dictyostelium discoideum and the larvae of the insect Galleria mellonella, and reduced in vivo fitness in a mouse model of peritoneal sepsis. Despite A. baumannii genome plasticity, the O-glycosylation machinery appears to be present in all clinical isolates tested as well as in all of the genomes sequenced. This suggests the existence of a strong evolutionary pressure to retain this system. These results together indicate that O-glycosylation in A. baumannii is required for full virulence and therefore represents a novel target for the development of new antibiotics

Genetic and molecular analyses reveal an evolutionary trajectory for glycan synthesis in a bacterial protein glycosylation system

This article contains supporting information online at www.pnas.org/lookup/suppl/doi:10. 1073/pnas.1103321108/-/DCSupplemental.Although protein glycosylation systems are becoming widely recognized in bacteria, little is known about the mechanisms and evolutionary forces shaping glycan composition. Species within the genus Neisseria display remarkable glycoform variability associated with their O-linked protein glycosylation (pgl) systems and provide a well developed model system to study these phenomena. By examining the potential influence of two ORFs linked to the core pgl gene locus, we discovered that one of these, previously designated as pglH, encodes a glucosyltransferase that generates unique disaccharide products by using polyprenyl diphosphate-linked monosaccharide substrates. By defining the function of PglH in the glycosylation pathway, we identified a metabolic conflict related to competition for a shared substrate between the opposing glycosyltransferases PglA and PglH. Accordingly, we propose that the presence of a stereotypic, conserved deletion mutation inactivating pglH in strains of Neisseria gonorrhoeae, Neisseria meningitidis, and related commensals, reflects a resolution of this conflict with the consequence of reduced glycan diversity. This model of genetic détente is supported by the characterization of pglH "missense" alleles encoding proteins devoid of activity or reduced in activity such that they cannot exert their effect in the presence of PglA. Thus, glucose-containing glycans appear to be a trait undergoing regression at the genus level. Together, these findings document a role for intrinsic genetic interactions in shaping glycan evolution in protein glycosylation systems.Research Council of Norway (Grant 166931)Research Council of Norway (Grant 183613)Research Council of Norway (Grant 183814)University of Oslo. Department of Molecular BiosciencesUniversity of Oslo. Center for Molecular Biology and NeurosciencesUnited States. National Institutes of Health (Grant GM039334

The Desire for Body Contouring Surgery after Bariatric Surgery

Background: Obesity has become far more prevalent over the last few decades. In parallel, bariatric surgery has been increasingly utilized as a method of treatment. This appears to be having an impact on the rate of body contouring surgery for hanging redundant skin after the massive weight loss that usually results from bariatric surgery. Little literature is available addressing how frequently patients who have undergone bariatric surgery receive or desire body contouring surgery or regarding how satisfied these patients are with the hanging skin in certain body areas. Methods: Seventy individuals (out of 250 who were mailed the questionnaire) who had undergone Roux-en-Y gastric bypass surgery 6–10 years previously completed a questionnaire, which obtained information regarding their experiences with as well as their desire for body contouring surgery and more general body area satisfaction. Results: Thirty three of the seventy patients reported having undergone a total of 38 body contouring procedures. The most common were abdominoplasties (24.3%), breast lifts (8.6%), and thigh lifts (7.1%). However, subjects were not uniformly satisfied with body areas that had undergone body contouring surgery; some found the areas unattractive. The majority of patients, at least to some extent, desired body contouring surgery, often in several areas, most notably the waist/abdomen, rear/buttock, upper arms, and chest/breast. Conclusion: Paralleling the increasing use of bariatric surgery is an increasing desire for body contouring surgery. Most patients desire body contouring surgery after bariatric surgery. However, third party payors usually do not reimburse for such procedures

“Inverted-Y”: A Modified Vest-Over-Pants Abdominoplasty Pattern Following Bariatric Surgery

The post-bariatric surgery patient presents several challenges to the surgeon. Correction of skin and subcutaneous redundancy can be difficult, particularly in massive-weight-loss patients with horizontal laxity, upper abdominal or flank laxity, and "double-roll" deformities. The aim of our study was to propose our modification of the "vest-over-pants" abdominoplasty technique to exploit all the advantages of the Planas technique in bariatric surgery patients and to solve the problem of extreme epigastric skin redundancy in difficult abdominal contour cases