http://hdl.handle.net/10033/6815 Abt. Medizinische Mikrobiologie (MMIK) Tue, 21 May 2013 18:49:22 GMT 2013-05-21T18:49:22Z http://hdl.handle.net/10033/291139 Title: Sphingomonas starnbergensis sp. nov., isolated from a prealpine freshwater lake. Authors: Chen, Hong; Jogler, Mareike; Tindall, Brian J; Klenk, Hans-Peter; Rohde, Manfred; Busse, Hans-Jürgen; Overmann, Jörg Abstract: A novel type of freshwater bacterium was isolated from the prealpine mesotrophic Starnberger See (Bavaria, southern Germany). Cells of strain 382(T) were Gram-negative and rod-shaped, motile and creamy-white. The isolate was strictly aerobic, catalase- and oxidase-positive, and grew at pH values of 6-9 (optimum, pH 7) and temperatures of 10-37 °C (optimum, 28 °C). The genomic G+C content of strain 382(T) was 64.1 mol%. Based on 16S rRNA gene sequence analyses, strain 382(T) belongs to the family Sphingomonadaceae and clusters within the genus Sphingomonas. Sphingomonas histidinilytica UM 2(T) and Sphingomonas wittichii DSM 6014(T) were the closest relatives, as indicated by the highest 16S rRNA gene sequence similarities (97.1 % and 96.8 %, respectively). Sphingomonas paucimobilis DSM 1098(T) (the type species of the genus Sphingomonas) exhibited 95.3 % sequence similarity. This affiliation of strain 382(T) to the genus Sphingomonas is confirmed by the presence of Q-10 as the major respiratory quinone, two sphingoglycolipids, C14 : 0 2-OH as the major 2-hydroxy fatty acid and sym-homospermidine as the major polyamine. The main cellular fatty acids of strain 382(T) were C18 : 1ω7c (39 %), C16 : 1ω7c (21 %), C16 : 0 (10 %) and C14 : 0 2-OH (10 %). Based on the phylogenetic distance from other species of the genus Sphingomonas and its unusually high C16 : 1ω7c content, strain 382(T) represents a novel species of the genus Sphingomonas, for which the name Sphingomonas starnbergensis is proposed. The type strain is 382(T) ( = DSM 25077(T)  = LMG 26763(T)). Fri, 01 Mar 2013 00:00:00 GMT http://hdl.handle.net/10033/291139 2013-03-01T00:00:00Z http://hdl.handle.net/10033/281353 Title: Cellular immune reactions in the lung. Authors: Hasenberg, Mike; Stegemann-Koniszewski, Sabine; Gunzer, Matthias Abstract: The lung constantly interacts with the environment through thousands of liters of air that are inhaled daily. This continually transports toxic chemicals and particles or pathogenic microorganisms deep into the respiratory system, posing a challenge to physicochemical barriers and the local immune system. Thus, complex structures and mechanisms have evolved to recognize and fend off environmental dangers while at the same time allowing efficient gas exchange. Here we review our current knowledge regarding cellular mechanisms of the immune system in context with the highly specialized anatomical features of the airways and especially the alveolar compartment. The focus is on fungal and viral infections, merging anatomical aspects well known to pulmonologists with fundamental immunological concepts. We discuss the specialized morphological constraints of immune cells compressed under a continuous layer of the surfactant lining within alveoli as well as the importance of functional polarization of respiratory tract epithelia. Furthermore, we summarize the different types of innate and adaptive immune cells and their relative contribution to lung homeostasis with respect to localization. Finally, we provide a list of currently unresolved questions with high relevance for the field that might serve as food for thought regarding future research directions. Tue, 01 Jan 2013 00:00:00 GMT http://hdl.handle.net/10033/281353 2013-01-01T00:00:00Z http://hdl.handle.net/10033/275713 Title: From the test tube to the environment - and back. Authors: de Lorenzo, Victor; Pieper, Dietmar; Ramos, Juan L Tue, 01 Jan 2013 00:00:00 GMT http://hdl.handle.net/10033/275713 2013-01-01T00:00:00Z http://hdl.handle.net/10033/274372 Title: Cooperative Plasminogen Recruitment to the Surface of Streptococcus canis via M Protein and Enolase Enhances Bacterial Survival. Authors: Fulde, Marcus; Rohde, Manfred; Polok, Andy; Preissner, Klaus T; Chhatwal, Gursharan Singh; Bergmann, Simone Abstract: ABSTRACT Streptococcus canis is a zoonotic pathogen capable of causing serious invasive diseases in domestic animals and humans. Surface-exposed M proteins and metabolic enzymes have been characterized as major virulence determinants in various streptococcal species. Recently, we have identified SCM, the M-like protein of S. canis, as the major receptor for miniplasminogen localized on the bacterial surface. The present study now characterizes the glycolytic enzyme enolase as an additional surface-exposed plasminogen-binding protein. According to its zoonotic properties, purified S. canis enolase binds to both human and canine plasminogen and facilitates degradation of aggregated fibrin matrices after activation with host-derived urokinase-type plasminogen activator (uPA). Unlike SCM, which binds to the C terminus of human plasminogen, the S. canis enolase interacts N terminally with the first four kringle domains of plasminogen, representing angiostatin. Radioactive binding analyses confirmed cooperative plasminogen recruitment to both surface-exposed enolase and SCM. Furthermore, despite the lack of surface protease activity via SpeB in S. canis, SCM is released and reassociated homophilically to surface-anchored SCM and heterophilically to surface-bound plasminogen. In addition to plasminogen-mediated antiphagocytic activity, reassociation of SCM to the bacterial surface significantly enhanced bacterial survival in phagocytosis analyses using human neutrophils. IMPORTANCE Streptococcal infections are a major issue in medical microbiology due to the increasing spread of antibiotic resistances and the limited availability of efficient vaccines. Surface-exposed glycolytic enzymes and M proteins have been characterized as major virulence factors mediating pathogen-host interaction. Since streptococcal infection mechanisms exert a subset of multicombinatorial processes, the investigation of synergistic activities mediated via different virulence factors has become a high priority. Our data clearly demonstrate that plasminogen recruitment to the Streptococcus canis surface via SCM and enolase in combination with SCM reassociation enhances bacterial survival by protecting against phagocytic killing. These data propose a new cooperative mechanism for prevention of phagocytic killing based on the synergistic activity of homophilic and heterophilic SCM binding in the presence of human plasminogen. Tue, 01 Jan 2013 00:00:00 GMT http://hdl.handle.net/10033/274372 2013-01-01T00:00:00Z