In the past years, numerous genomes of pro-and eukaryotic microbial organisms have been sequenced, paving the way for high-throughput genome and post-genome analysis. In the current "post-genomic" era, these data are examined to allow detection of relevant biological functions. The so-called "-omics" term has been created, involving genomics, transcriptomics, proteomics, metabolomics, and others. All these techniques deal with large-scale data sets and analyze or compare genes, transcripts, proteins and metabolites either from different organisms or within an organism in different sub-cellular compartments and under different conditions. These approaches can provide new insights into (i) the evolution of individual genes or gene clusters that are involved in specifi c cellular pathways, (ii) transcript profi les under different conditions, to which the cells have been exposed, (iii) the protein composition of cells modulated by various factors or of specifi c sub-cellular compartments, (iv) changes in the metabolome status e.g. under different growth conditions. The involved methods in this growing fi eld include bioinformatic tools, micro-and macro-arrays, separation methods such as 2-dimensional gel electrophoresis for proteins, as well as mass spectrometry in combination with liquid or gas chromatography.
The "-omics" fi eld is rapidly progressing, along with new instruments such as mass spectrometers that can identify proteins down to the attomolar range. The large-scale data-sets produced usually require effi cient bioinformatic evaluation and modeling, leading to a more holistic understanding of biological processes such as computed in systems biology. In the future, these new insights into biological processes will be prerequisite to allow their modulation in applied sciences including biotechnology.
The current special issue of the Journal of Basic Microbiology focuses on the different up-to-date "omics" approaches, especially with regard to comparative genomics, transcriptomics based on array studies, and comparison of proteomes and metabolomes in various microbial organisms, focusing on a variety of relevant biological processes.