Browsing by Subject "surfaceome"

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  • Savijoki, Kirsi; Miettinen, Ilkka; Nyman, Tuula; Kortesoja, Maarit; Hanski, Leena; Varmanen, Pekka; Fallarero, Adyary (2020)
    The present study investigated Staphylococcus aureus ATCC25923 surfaceomes (cell surface proteins) during prolonged growth by subjecting planktonic and biofilm cultures (initiated from exponential or stationary cells) to label-free quantitative surfaceomics and phenotypic confirmations. The abundance of adhesion, autolytic, hemolytic, and lipolytic proteins decreased over time in both growth modes, while an opposite trend was detected for many tricarboxylic acid (TCA) cycle, reactive oxygen species (ROS) scavenging, Fe-S repair, and peptidolytic moonlighters. In planktonic cells, these changes were accompanied by decreasing and increasing adherence to hydrophobic surface and fibronectin, respectively. Specific RNA/DNA binding (cold-shock protein CspD and ribosomal proteins) and the immune evasion (SpA, ClfA, and IsaB) proteins were notably more abundant on fully mature biofilms initiated with stationary-phase cells (SDBF) compared to biofilms derived from exponential cells (EDBF) or equivalent planktonic cells. The fully matured SDBF cells demonstrated higher viability in THP-1 monocyte/macrophage cells compared to the EDBF cells. Peptidoglycan strengthening, specific urea-cycle, and detoxification enzymes were more abundant on planktonic than biofilm cells, indicating the activation of growth-mode specific pathways during prolonged cultivation. Thus, we show that S. aureus shapes its surfaceome in a growth mode-dependent manner to reach high levofloxacin tolerance (>200-times the minimum biofilm inhibitory concentration). This study also demonstrates that the phenotypic state of the cells prior to biofilm formation affects the immune-evasion and persistence-related traits of S. aureus.
  • Sillanpää, Annika (Helsingin yliopisto, 2020)
    The scientific data has demonstrated that surface-associated proteins have a significant role affecting the adaptation to GIT environment, adherence to the intestinal mucus and other potential health benefits occurring through cross-talk of propionibacteria and the host. The reported achievements on the complementary proteomic approaches optimize the accuracy of surface protein identification and surface proteins related to anti-inflammatory activities and adhesion has been identified from Propionibacterium freudenreichii strains. Thus, the aim of this thesis was to compare the effect of atmospheric conditions on surfaceome expression of the P. freudenreichii type strain DSM 20271. Bacterial cultures cultivated in aerobic and anaerobic atmosphere were harvested at the mid-exponential phase of growth. Samples were subjected to gel-free proteomic analysis, based on direct analysis of peptides acquired by trypsin cell-surface shaving followed by identification of released surface-attached proteins and peptides using LC-MS/MS and label-free quantification. It was demonstrated in this work that different atmospheric conditions highly influenced the protein expression patterns. Overall, the expression of more than a hundred proteins were affected by the change of environmental condition, of which the majority were predicted not to include either classical nor non-classical secretion motifs. It is still unresolved question if these cytoplasmic proteins in the shaved-fraction could be transported to the bacterial surface area by uncharacterized mechanisms to serve a specific moonlighting function. Few of the identified proteins, most of which were up-regulated in aerobic growth condition, were already described in other bacterial species to be involved with general stress response (ClpP, ClpB, and Ctc) and reduction of reactive oxygen species (Tpx, AhpC, and AhpF).
  • Hiltunen, Anna; Savijoki, Kirsi; Nyman, Tuula; Miettinen, Ilkka; Ihalainen, Petri; Peltonen, Jouko; Fallarero, Adyary (2019)
    Medical device-associated staphylococcal infections are a common and challenging problem. However, detailed knowledge of staphylococcal biofilm dynamics on clinically relevant surfaces is still limited. In the present study, biofilm formation of the Staphylococcus aureus ATCC 25923 strain was studied on clinically relevant materials-borosilicate glass, plexiglass, hydroxyapatite, titanium and polystyrene-at 18, 42 and 66 h. Materials with the highest surface roughness and porosity (hydroxyapatite and plexiglass) did not promote biofilm formation as efficiently as some other selected materials. Matrix-associated poly-N-acetyl-beta-(1-6)-glucosamine (PNAG) was considered important in young (18 h) biofilms, whereas proteins appeared to play a more important role at later stages of biofilm development. A total of 460 proteins were identified from biofilm matrices formed on the indicated materials and time points-from which, 66 proteins were proposed to form the core surfaceome. At 18 h, the appearance of several r-proteins and glycolytic adhesive moonlighters, possibly via an autolysin (AtlA)-mediated release, was demonstrated in all materials, whereas classical surface adhesins, resistance- and virulence-associated proteins displayed greater variation in their abundances depending on the used material. Hydroxyapatite-associated biofilms were more susceptible to antibiotics than biofilms formed on titanium, but no clear correlation between the tolerance and biofilm age was observed. Thus, other factors, possibly the adhesive moonlighters, could have contributed to the observed chemotolerant phenotype. In addition, a protein-dependent matrix network was observed to be already well-established at the 18 h time point. To the best of our knowledge, this is among the first studies shedding light into matrix-associated surfaceomes of S. aureus biofilms grown on different clinically relevant materials and at different time points.
  • Reigada, Inés; San-Martin-Galindo, Paola; Gilbert-Girard, Shella; Chiaro, Jacopo; Cerullo, Vincenzo; Savijoki, Kirsi; Nyman, Tuula A.; Fallarero, Adyary; Miettinen, Ilkka (2021)
    Bacterial biofilms are an important underlying cause for chronic infections. By switching into the biofilm state, bacteria can evade host defenses and withstand antibiotic chemotherapy. Despite the fact that biofilms at clinical and environmental settings are mostly composed of multiple microbial species, biofilm research has largely been focused on single-species biofilms. In this study, we investigated the interaction between two clinically relevant bacterial pathogens (Staphylococcus aureus and Pseudomonas aeruginosa) by label-free quantitative proteomics focusing on proteins associated with the bacterial cell surfaces (surfaceome) and proteins exported/released to the extracellular space (exoproteome). The changes observed in the surfaceome and exoproteome of P. aeruginosa pointed toward higher motility and lower pigment production when co-cultured with S. aureus. In S. aureus, lower abundances of proteins related to cell wall biosynthesis and cell division, suggesting increased persistence, were observed in the dual-species biofilm. Complementary phenotypic analyses confirmed the higher motility and the lower pigment production in P. aeruginosa when co-cultured with S. aureus. Higher antimicrobial tolerance associated with the co-culture setting was additionally observed in both species. To the best of our knowledge, this study is among the first systematic explorations providing insights into the dynamics of both the surfaceome and exoproteome of S. aureus and P. aeruginosa dual-species biofilms.