Staphylococcus Research Today is a free monthly online journal that collates and summarizes the latest research about Staphylococcus, including details on mrsa, hospitals, infection, antibiotic resistance, superbugs. | ||||||||
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Localized tufts of fibrils on Staphylococcus epidermidis NCTC 11047 are comprised of the accumulation-associated protein.Banner MA, Cunniffe JG, Macintosh RL, Foster TJ, Rohde H, Mack D, Hoyes E, Derrick J, Upton M, Handley PS Faculty of Life Sciences, 1.800 Stopford Building, The University of Manchester, Oxford Road, Manchester M13 9PT, United Kingdom. Staphylococcus epidermidis is both a human skin commensal and an opportunistic pathogen, causing infections linked to implanted medical devices. This paper describes localized tufts of fibrillar appendages on a subpopulation (25%) of wild-type (WT) S. epidermidis NCTC 11047 cells. The fibrils (122.2 +/- 10.8 nm long) are usually in a lateral position on the cells. Fibrillar (Fib(+)) and nonfibrillar (Fib(-)) subpopulations were separated (enriched) by 34 sequential partitions of WT cells between a buffer phase and a hexadecane phase. Following enrichment, hydrophobic cells from the hexadecane phase comprised 70% Fib(+) cells and the less hydrophobic cells from the buffer phase entirely comprised Fib(-) cells. The Fib(+) and Fib(-) subpopulations did not revert on subculture (34 times) on solid medium. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of cell surface proteins from WT, Fib(+), and Fib(-) cells revealed two high-molecular-mass proteins (280 kDa and 230 kDa) on the WT and Fib(+) cells that were absent from the Fib(-) cells. Amino acid sequencing revealed that fragments of both the 280- and 230-kDa proteins had 100% identity to the accumulation-associated protein (Aap). Aap is known to cause biofilm formation if it is truncated by loss of the terminal A domain. Immunogold staining with anti-Aap antibodies labeled tuft fibrils of the WT and Fib(+) cells but not the cell surface of Fib(-) cells. The tufts were labeled with N-terminally directed antibodies (anti-A domain), showing that the fibrillar Aap was not truncated on the cell surface. Thus, the presence of full-length Aap correlated with the low biofilm-forming abilities of both WT and Fib(+) S. epidermidis NCTC 11047 populations. Reverse transcription-PCR showed that aap was transcribed in both Fib(+) and Fib(-) cells. We therefore propose that full-length Aap is expressed on cells of S. epidermidis NCTC 11047 as tufts of short fibrils and that fibril expression is regulated at a posttranscriptional level. Published 19 March 2007 in J Bacteriol, 189(7): 2793-804.
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