In conclusion, 15/57 strains of O157:non-H7 serotypes isolated from different sources and geographical regions were found
to carry various eae alleles, suggesting that these strains may be fairly prevalent. Many of the O157:H16 strains found, including strains that were isolated from water in the United States and from meat in France, carried the ɛ-eae allele, shared similar PFGE profiles and had ST-171, a common type in the EcMLST database that, until now, had not included any strains from the O157 serogroup. Clonal analysis also showed that none of these eae-positive O157:non-H7 strains were closely related to the pathogenic O157:H7 serotype and that there is a large genetic diversity within the O157 serogroup. The authors would like to dedicate this work to the memory selleck of Dr Thomas S. Whittam. “
“The potential for microbial fuel cells to act as an alternative, pollution-neutral energy source has generated a major PARP inhibitor cancer increase in the number of publications on this subject. Fundamental to the functioning of a microbial fuel cell, and the efficient transfer of electrons to an associated electrical network, is the formation of specialized biofilms on an electrode surface. Microarray studies
of these biofilms have important considerations that are also fundamental for biofilm gene expression studies in general. Cells in a biofilm exist in a range of different physiological states, but global analysis generalizes transcription across the entire biofilm population. This leads to the common pitfall of a complex system being overly simplified. Bacteria stiripentol are commonly found in the environment as part of surface-associated communities known as biofilms. Through the formation of a biofilm, bacteria gain many advantages, such as an increased resistance to desiccation, resistance to antibiotics, defence against grazing, and increased metabolic function, among others. Biofilms are studied extensively due to their importance in environmental, industrial, and medical processes. They are highly hydrated structures containing cells encased in an extracellular matrix of proteins, DNA, enzymes, and
extracellular polymeric substances. Many bacterial biofilms consist of structured clumps of cells surrounded by channels void of cellular material, in which nutrients and waste can be exchanged, resulting in a diverse range of microenvironments. For example, electrical-producing biofilms in a microbial fuel cell can be >50 μm thick, have been shown to contain proton gradients, and are suspected to contain electrical potential and nutrient gradients. Transcriptional profiling has become the tool of choice for microbiologists to examine changes in gene expression. Microarrays are powerful tools that allow for the examination of genome-wide changes in gene expression in either isogenic mutant strains or different environmental conditions.