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Université de Fribourg

The effects of temperature and dispersal on species diversity in natural microbial metacommunities

Parain, Elodie C. ; Gray, Sarah M. ; Bersier, Louis-Félix

In: Scientific Reports, 2019, vol. 9, no. 1, p. 18286

Dispersal is key for maintaining biodiversity at local- and regional scales in metacommunities. However, little is known about the combined effects of dispersal and climate change on biodiversity. Theory predicts that alpha-diversity is maximized at intermediate dispersal rates, resulting in a hump-shaped diversity-dispersal relationship. This relationship is predicted to flatten when...

Université de Fribourg

Phenotypic, biochemical, and genetic analysis of kpc-41, a kpc-3 variant conferring resistance to ceftazidime-avibactam and exhibiting reduced carbapenemase activity

Mueller, Linda ; Masseron, Amandine ; Prod’Hom, Guy ; Galperine, Tatiana ; Greub, Gilbert ; Poirel, Laurent ; Nordmann, Patrice

In: Antimicrobial Agents and Chemotherapy, 2019, vol. 63, no. 12, p. -

A novel KPC variant, KPC-41, was identified in a Klebsiella pneumoniae clinical isolate from Switzerland. This β-lactamase possessed a 3-amino-acid insertion (Pro- Asn-Lys) located between amino acids 269 and 270 compared to the KPC-3 amino acid sequence. Cloning and expression of the blaKPC-41 gene in Escherichia coli, followed by determination of MIC values and kinetic parameters, showed...

Università della Svizzera italiana

Phenotype and specificity of T cells in primary human cytomegalovirus infection during pregnancy : IL-7Rpos long-term memory phenotype is associated with protection from vertical transmission

Mele, Federico ; Fornara, Chiara ; Jarrossay, David ; Furione, Milena ; Arossa, Alessia ; Spinillo, Arsenio ; Lanzavecchia, Antonio ; Gerna, Giuseppe ; Sallusto, Federica ; Lilleri, Daniele

In: Plos one, 2017, vol. 12, no. 11, p. e0187731

Congenital human cytomegalovirus (HCMV) infection is the major cause of birth defects and a precise definition of the HCMV-specific T-cell response in primary infection may help define reliable correlates of immune protection during pregnancy. In this study, a high throughput method was used to define the frequency of CD4+ and CD8+ T cells specific for four HCMV proteins in the naïve...

Università della Svizzera italiana

Molecular signatures of immunity and immunogenicity in infection and vaccination

Haks, Mariëlle C. ; Bottazzi, Barbara ; Cecchinato, Valentina ; De Gregorio, Corinne ; Del Giudice, Giuseppe ; Kaufmann, Stefan H. E. ; Lanzavecchia, Antonio ; Lewis, David J. M. ; Maertzdorf, Jeroen ; Mantovani, Alberto ; Sallusto, Federica ; Sironi, Marina ; Uguccioni, Mariagrazia ; Ottenhoff, Tom H. M.

In: Frontiers in immunology, 2017, vol. 8, p. 1563

Vaccinology aims to understand what factors drive vaccine-induced immunity and protection. For many vaccines, however, the mechanisms underlying immunity and protection remain incompletely characterized at best, and except for neutralizing antibodies induced by viral vaccines, few correlates of protection exist. Recent omics and systems biology big data platforms have yielded valuable...

Università della Svizzera italiana

Conformational occlusion of blockade antibody epitopes, a novel mechanism of GII.4 human norovirus immune evasion

Lindesmith, Lisa C. ; Mallory, Michael L. ; Debbink, Kari ; Donaldson, Eric F. ; Brewer-Jensen, Paul D. ; Swann, Excel W. ; Sheahan, Timothy P. ; Graham, Rachel L. ; Beltramello, Martina ; Corti, Davide ; Lanzavecchia, Antonio ; Baric, Ralph S.

In: mSphere, 2018, vol. 3, no. 1, p. e00518-17

Extensive antigenic diversity within the GII.4 genotype of human norovirus is a major driver of pandemic emergence and a significant obstacle to development of cross- protective immunity after natural infection and vaccination. However, human and mouse monoclonal antibody studies indicate that, although rare, antibodies to conserved GII.4 blockade epitopes are generated. The mechanisms by...

Université de Fribourg

Distribution and restoration of serotonin-immunoreactive paraneuronal cells during caudal fin regeneration in zebrafish

König, Désirée ; Dagenais, Paule ; Senk, Anita ; Djonov, Valentin ; Aegerter, Christof M. ; Jaźwińska, Anna

In: Frontiers in Molecular Neuroscience, 2019, vol. 12, p. -

Aquatic vertebrates possess diverse types of sensory cells in their skin to detect stimuli in the water. In the adult zebrafish, a common model organism, the presence of such cells in fins has only rarely been studied. Here, we identified scattered serotonin (5-HT)-positive cells in the epidermis of the caudal fin. These cells were distinct from keratinocytes as revealed by their low...

Université de Neuchâtel

Under-detection of endospore-forming Firmicutes in metagenomic data

Filippidou, Sevasti ; Junier, Thomas ; Wunderlin, Tina ; Lo, Chien-Chi ; Li, Po-E ; Chain, Patrick S ; Junier, Pilar

In: Computational and Structural Biotechnology Journal, 2015, vol. 13, p. 299-206

Microbial diversity studies based on metagenomic sequencing have greatly enhanced our knowledge of the microbial world. However, one caveat is the fact that not all microorganisms are equally well detected, questioning the universality of this approach. Firmicutes are known to be a dominant bacterial group. Several Firmicutes species are endospore formers and this property makes...

Università della Svizzera italiana

T follicular helper cells promote a beneficial gut ecosystem for host metabolic homeostasis by sensing microbiota-derived extracellular ATP

Perruzza, Lisa ; Gargari, Giorgio ; Proietti, Michele ; Fosso, Bruno ; D'Erchia, Anna Maria ; Faliti, Caterina Elisa ; Rezzonico-Jost, Tanja ; Scribano, Daniela ; Mauri, Laura ; Colombo, Diego ; Pellegrini, Giovanni ; Moregola, Annalisa ; Mooser, Catherine ; Pesole, Graziano ; Nicoletti, Mauro ; Norata, Giuseppe Danilo ; Geuking, Markus B. ; McCoy, Kathy D. ; Guglielmetti, Simone ; Grassi, Fabio

In: Cell reports, 2017, vol. 18, no. 11, p. 2566-2575

The ATP-gated ionotropic P2X7 receptor regulates T follicular helper (Tfh) cell abundance in the Peyer’s patches (PPs) of the small intestine; deletion of P2rx7, encoding for P2X7, in Tfh cells results in enhanced IgA secretion and binding to commensal bacteria. Here, we show that Tfh cell activity is important for generating a diverse bacterial community in the gut and that sensing of...

Université de Neuchâtel

New frontiers of ultrafast thin-disk laser oscillators for applications in metrology and the generation of THz and XUV radiation

Modsching, Norbert Paul ; Südmeyer, Thomas (Dir.)

Thèse de doctorat : Université de Neuchâtel, 2019.

Ultrafast laser systems find application as versatile tool in industry and science. Ultrafast laser systems based on Ti:sapphire – the workhorse in ultrafast science – operate typically at kHz repetition rates and benefit from the available broad gain bandwidth for the direct generation of sub 100-fs pulse durations. However, thermal effects in the gain medium due to a high quantum defect...

Università della Svizzera italiana

Main steps in DNA double-strand break repair : An introduction to homologous recombination and related processes

Ranjha, Lepakshi ; Howard, Sean Michael ; Cejka, Petr

In: Chromosoma, 2018, vol. 127, no. 2 (June), p. 187–214

DNA double-strand breaks arise accidentally upon exposure of DNA to radiation, chemicals or result from faulty DNA metabolic processes. DNA breaks can also be introduced in a programmed manner, such as during the maturation of the immune system, meiosis or cancer chemo- or radiotherapy. Cells have developed a variety of repair pathways, which are fine-tuned to the specific needs of a cell....