We studied the early stages of pellicle formation by Mycobacterium smegmatis on the surface of a liquid medium [air-liquid interface (A-L)]. Using optical and scanning electron microscopy, we showed the formation of a compact biofilm pellicle from micro-colonies over a period of 8-30 h. The cells in the pellicle changed size and cell division pattern during this period. Based on our findings, we created a model of M. smegmatis A-L early pellicle formation showing the coordinate growth of cells in the micro-colonies and in the homogeneous film between them, where the accessibility to oxygen and nutrients is different. A proteomic approach utilizing high-resolution two-dimensional gel electrophoresis, in combination with mass spectrometry-based protein identification, was used to analyse the protein expression profiles of the different morphological stages of the pellicle. The proteins identified formed four expression groups; the most interesting of these groups contained the proteins with highest expression in the biofilm development phase, when the floating micro-colonies containing long and more robust cells associate into flocs and start to form a compact pellicle. The majority of these proteins, including GroEL1, are involved in cell wall synthesis or modification, mostly through the involvement of mycolic acid biosynthesis, and their expression maxima correlated with the changes in cell size and the rigidity of the bacterial cell wall observed by scanning electron microscopy.
- MeSH
- 2D gelová elektroforéza MeSH
- bakteriální proteiny genetika metabolismus MeSH
- biofilmy růst a vývoj MeSH
- biologické modely MeSH
- buněčná stěna metabolismus MeSH
- kultivační média MeSH
- mikroskopie elektronová rastrovací MeSH
- Mycobacterium smegmatis genetika růst a vývoj fyziologie ultrastruktura MeSH
- proteomika * MeSH
- regulace genové exprese u bakterií * MeSH
- spektrometrie hmotnostní - ionizace laserem za účasti matrice MeSH
- vzduch MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
We studied the impact of a sublethal concentration of erythromycin on the fitness and proteome of a continuously cultivated population of Escherichia coli. The development of resistance to erythromycin in the population was followed over time by the gradient plate method and minimum inhibitory concentration (MIC) measurements. We measured the growth rate, standardized efficiency of synthesis of radiolabeled proteins, and translation accuracy of the system. The proteome changes were followed over time in two parallel experiments that differed in the presence or absence of erythromycin. A comparison of the proteomes at each time point (43, 68, and 103 h) revealed a group of unique proteins differing in expression. From all 35 proteins differing throughout the cultivation, only three were common to more than one time point. In the final population, a significant proportion of upregulated proteins was localized to the outer or inner cytoplasmic membranes or to the periplasmic space. In a population growing for more than 100 generations in the presence of antibiotic, erythromycin-resistant bacterial clones with improved fitness in comparison to early resistant culture predominated. This phenomenon was accompanied by distinct changes in protein expression during a stepwise, population-based development of erythromycin resistance.
- MeSH
- antibakteriální látky farmakologie MeSH
- bakteriální léková rezistence genetika MeSH
- časové faktory MeSH
- erythromycin farmakologie MeSH
- Escherichia coli účinky léků genetika metabolismus MeSH
- genetická zdatnost účinky léků MeSH
- kultivační média MeSH
- mikrobiální testy citlivosti MeSH
- proteiny z Escherichia coli genetika metabolismus MeSH
- proteom genetika metabolismus MeSH
- regulace genové exprese u bakterií * MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Using intracerebral EEG recordings in a large cohort of human subjects, we investigate the time course of neural cross-talk during a simple cognitive task. Our results show that human brain dynamics undergo a characteristic sequence of synchronization patterns across different frequency bands following a visual oddball stimulus. In particular, an initial global reorganization in the delta and theta bands (2-8 Hz) is followed by gamma (20-95 Hz) and then beta band (12-20 Hz) synchrony.
- MeSH
- dospělí MeSH
- elektroencefalografie MeSH
- kognice fyziologie MeSH
- korová synchronizace fyziologie MeSH
- lidé MeSH
- mladiství MeSH
- mladý dospělý MeSH
- mozek fyziologie MeSH
- Check Tag
- dospělí MeSH
- lidé MeSH
- mladiství MeSH
- mladý dospělý MeSH
- mužské pohlaví MeSH
- ženské pohlaví MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
Streptomycetes, soil-dwelling mycelial bacteria, can colonise surface of organic soil debris and soil particles. We analysed the effects of two different inert surfaces, glass and zirconia/silica, on the growth and antibiotic production in Streptomyces granaticolor. The surfaces used were in the form of microbeads and were surrounded by liquid growth media. Following the production of the antibiotic granaticin, more biomass was formed as well as a greater amount of antibiotic per milligram of protein on the glass beads than on the zirconia/silica beads. Comparison of young mycelium (6 h) proteomes, obtained from the cultures attached to the glass and zirconia/silica beads, revealed three proteins with altered expression levels (dihydrolipoamide dehydrogenase, amidophosphoribosyltransferase and cystathionine beta-synthase) and one unique protein (glyceraldehyde-3-phosphate dehydrogenase) that was present only in cells grown on glass beads. All of the identified proteins function primarily as cytoplasmic enzymes involved in different parts of metabolism; however, in several microorganisms, they are exposed on the cell surface and have been shown to be involved in adhesion or biofilm formation.
- MeSH
- antibakteriální látky metabolismus MeSH
- bakteriální adheze * MeSH
- bakteriální proteiny biosyntéza MeSH
- biomasa MeSH
- exprese genu MeSH
- hydrofobní a hydrofilní interakce * MeSH
- imobilizované buňky chemie metabolismus fyziologie MeSH
- naftochinony metabolismus MeSH
- povrchové vlastnosti * MeSH
- Streptomyces chemie růst a vývoj fyziologie MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- MeSH
- mikrobiologie * MeSH
- odměny a ceny * MeSH
- Publikační typ
- biografie MeSH
253 s. : tab., grafy ; 24 cm
- Konspekt
- Mikrobiologie
- NLK Obory
- mikrobiologie, lékařská mikrobiologie
- MeSH
- adenosinmonofosfát fyziologie MeSH
- Bacteria metabolismus MeSH
- lidé MeSH
- Check Tag
- lidé MeSH
