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

Echium Amoenum Fisch. Et Mey: A Review on its Pharmacological and Medicinal Properties

ABSTRACT: Echium amaenum, famous as Borage, belongs to Boraginaceae family. It grows widely in most of Europe, Mediterranean region and also found in northern parts of Iran. It is one of the famous plants in Iranian traditional medicine for different kind of effects such as demulcent, anti-inflammatory, analgesic, anxiolytic and sedative properties. The main medicinal parts of the plant are flowers and the leaves. The plant consists of gamma-linolenic acid (GLA), alphalinolenicacid (ALA), delta6-fatty acryl desaturase, delta8-sphingolipid desaturase, pyrrolizidine alkaloids, and mucilage, resin, potassium nitrate, calcium and mineral acids. This review focuses on pharmacological properties of Echium amaenum as antibacterial, antioxidants, analgesic, anxiolytic, antidepressant, immunomodulatory, protective effects on pancreatitis and antiviral agents