@article{DuehringGermerodtSkerkaetal.2015, author = {D{\"u}hring, Sybille and Germerodt, Sebastian and Skerka, Christine and Zipfel, Peter F. and Dandekar, Thomas and Schuster, Stefan}, title = {Host-pathogen interactions between the human innate immune system and Candida albicans - understanding and modeling defense and evasion strategies}, series = {Frontiers in Microbiology}, volume = {6}, journal = {Frontiers in Microbiology}, number = {625}, doi = {10.3389/fmicb.2015.00625}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-151621}, year = {2015}, abstract = {The diploid, polymorphic yeast Candida albicans is one of the most important human pathogenic fungi. C. albicans can grow, proliferate and coexist as a commensal on or within the human host for a long time. However, alterations in the host environment can render C. albicans virulent. In this review, we describe the immunological cross-talk between C. albicans and the human innate immune system. We give an overview in form of pairs of human defense strategies including immunological mechanisms as well as general stressors such as nutrient limitation, pH, fever etc. and the corresponding fungal response and evasion mechanisms. Furthermore, Computational Systems Biology approaches to model and investigate these complex interactions are highlighted with a special focus on game-theoretical methods and agent-based models. An outlook on interesting questions to be tackled by Systems Biology regarding entangled defense and evasion mechanisms is given.}, language = {en} } @article{BeckerOelschlaegerWullaertetal.2013, author = {Becker, Svetlana and Oelschlaeger, Tobias A. and Wullaert, Andy and Pasparakis, Manolis and Wehkamp, Jan and Stange, Eduard F. and Gersemann, Michael}, title = {Bacteria Regulate Intestinal Epithelial Cell Differentiation Factors Both In Vitro and In Vivo}, series = {PLoS ONE}, volume = {8}, journal = {PLoS ONE}, number = {2}, doi = {10.1371/journal.pone.0055620}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-131168}, pages = {e55620}, year = {2013}, abstract = {Background: The human colon harbours a plethora of bacteria known to broadly impact on mucosal metabolism and function and thought to be involved in inflammatory bowel disease pathogenesis and colon cancer development. In this report, we investigated the effect of colonic bacteria on epithelial cell differentiation factors in vitro and in vivo. As key transcription factors we focused on Hes1, known to direct towards an absorptive cell fate, Hath1 and KLF4, which govern goblet cell. Methods: Expression of the transcription factors Hes1, Hath1 and KLF4, the mucins Muc1 and Muc2 and the defensin HBD2 were measured by real-time PCR in LS174T cells following incubation with several heat-inactivated E. coli strains, including the probiotic E. coli Nissle 1917+/- flagellin, Lactobacilli and Bifidobacteria. For protein detection Western blot experiments and chamber-slide immunostaining were performed. Finally, mRNA and protein expression of these factors was evaluated in the colon of germfree vs. specific pathogen free vs. conventionalized mice and colonic goblet cells were counted. Results: Expression of Hes1 and Hath1, and to a minor degree also of KLF4, was reduced by E. coli K-12 and E. coli Nissle 1917. In contrast, Muc1 and HBD2 expression were significantly enhanced, independent of the Notch signalling pathway. Probiotic E. coli Nissle 1917 regulated Hes1, Hath1, Muc1 and HBD2 through flagellin. In vivo experiments confirmed the observed in vitro effects of bacteria by a diminished colonic expression of Hath1 and KLF4 in specific pathogen free and conventionalized mice as compared to germ free mice whereas the number of goblet cells was unchanged in these mice. Conclusions: Intestinal bacteria influence the intestinal epithelial differentiation factors Hes1, Hath1 and KLF4, as well as Muc1 and HBD2, in vitro and in vivo. The induction of Muc1 and HBD2 seems to be triggered directly by bacteria and not by Notch.}, language = {en} } @article{RoedelBredeHirschfeldetal.2013, author = {R{\"o}del, Mark-Oliver and Brede, Christian and Hirschfeld, Mareike and Schmitt, Thomas and Favreau, Philippe and St{\"o}cklin, Reto and Wunder, Cora and Mebs, Dietrich}, title = {Chemical Camouflage - A Frog's Strategy to Co-Exist with Aggressive Ants}, series = {PLOS ONE}, volume = {8}, journal = {PLOS ONE}, number = {12}, issn = {1932-6203}, doi = {10.1371/journal.pone.0081950}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-128181}, pages = {e81950}, year = {2013}, abstract = {Whereas interspecific associations receive considerable attention in evolutionary, behavioural and ecological literature, the proximate bases for these associations are usually unknown. This in particular applies to associations between vertebrates with invertebrates. The West-African savanna frog Phrynomantis microps lives in the underground nest of ponerine ants (Paltothyreus tarsatus). The ants usually react highly aggressively when disturbed by fiercely stinging, but the frog is not attacked and lives unharmed among the ants. Herein we examined the proximate mechanisms for this unusual association. Experiments with termites and mealworms covered with the skin secretion of the frog revealed that specific chemical compounds seem to prevent the ants from stinging. By HPLC-fractionation of an aqueous solution of the frogs' skin secretion, two peptides of 1,029 and 1,143 Da were isolated and found to inhibit the aggressive behaviour of the ants. By de novo sequencing using tandem mass spectrometry, the amino acid sequence of both peptides consisting of a chain of 9 and 11 residues, respectively, was elucidated. Both peptides were synthesized and tested, and exhibited the same inhibitory properties as the original frog secretions. These novel peptides most likely act as an appeasement allomone and may serve as models for taming insect aggression.}, language = {en} }