Morphological and proteomic analysis of early stage air-liquid interface biofilm formation in Mycobacterium smegmatis.
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.
Institute of Microbiology, Academy of Sciences of the Czech Republic, Prague, Czech Republic.
Zuzana
Z
Sochorová
Institute of Microbiology, Academy of Sciences of the Czech Republic, Prague, Czech Republic.
Denisa
D
Petráčková
Institute of Microbiology, Academy of Sciences of the Czech Republic, Prague, Czech Republic.
Barbora
B
Sitařová
Institute of Microbiology, Academy of Sciences of the Czech Republic, Prague, Czech Republic.
Karolína
K
Buriánková
Institute of Microbiology, Academy of Sciences of the Czech Republic, Prague, Czech Republic.
Silvia
S
Bezoušková
Department of Biology, Faculty of Science, J. E. Purkinje University in Ustí nad Labem, Ústí nad Labem, Czech Republic.|Institute of Microbiology, Academy of Sciences of the Czech Republic, Prague, Czech Republic.
Oldřich
O
Benada
Institute of Microbiology, Academy of Sciences of the Czech Republic, Prague, Czech Republic.
Olga
O
Kofroňová
Institute of Microbiology, Academy of Sciences of the Czech Republic, Prague, Czech Republic.
Jiří
J
Janeček
Institute of Microbiology, Academy of Sciences of the Czech Republic, Prague, Czech Republic.
Petr
P
Halada
Institute of Microbiology, Academy of Sciences of the Czech Republic, Prague, Czech Republic.
Jaroslav
J
Weiser
D000388:Air; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D018441:Biofilms / Q000254:growth & development*; D002473:Cell Wall / Q000378:metabolism; D003470:Culture Media; D015180:Electrophoresis, Gel, Two-Dimensional; D015964:Gene Expression Regulation, Bacterial; D008855:Microscopy, Electron, Scanning; D008954:Models, Biological; D020102:Mycobacterium smegmatis / Q000235:genetics / Q000254:growth & development / Q000502:physiology* / Q000648:ultrastructure; D040901:Proteomics; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
D001426:Bacterial Proteins; D003470:Culture Media