Finally, we have shown that the C59 wnt price planting area necessary for the cell population to maintain the “”feeling”" of belonging to a single body, roughly corresponds to the outer diameter of a mature interstitial circle (Figure 7c). Exceeding this critical diameter leads to the loss of structure and breakdown to a macula; however, even in such a case the body is self-inhibited as to lateral spreading. This may perhaps be understood as the last remnants of its “”feeling of integrity”"; the results of our computer simulations suggests that even this seemingly complex effect may be produced by the interplay of mere two signals. Conclusions

Some isolates of see more Serratia sp. produce

colonies exhibiting finite growth and clone-specific appearance, which is easily evaluated thanks to their conspicuous coloration. The shape and patterning of developing colonies and other multicellular bodies is easily malleable by experimental conditions. The appearance of a developing colony results from (i) its internal morphogenetic potential   (ii) the character of neighbor bodies and their overall distribution on the dish.   A simple formal model is proposed, based on two morphogenetic signals generated by the bodies, one of them spreading through the substrate and the other through the gas phase. The model can simulate some of our experimental results, namely: 1. 1. The MEK162 mw development of colonies exhibiting finite growth and both rimmed and rimless patterns, the difference between the former and the latter being in the intensity of signal production and/or sensitivity towards the signal(s).   2. 2. Dependence of colony size upon the number of colonies sharing common morphospace, and development of confluent colonies from closely

planted inocula of a rimmed strain.   3. 3. The phenomenon of “”critical planting area”" which must not be exceeded should a colony develop a typical rimmed pattern.   Our observations are thus consistent with bacterial colonies behaving, in some aspects, as true multicellular bodies whose patterning is controlled by positional information; the nature of the relevant signals remains to be established. Methods Strains, media and culture ioxilan conditions The strain Serratia rubidaea here labeled R (rimless “”wild type”" phenotype for the purpose of this study), as well as E. coli strain 281, were obtained from the collection of the Department of Genetics and Microbiology, Faculty of Sciences, Charles University. The R strain, originally described as S. marcescens, has been determined as S. rubidaea on the basis of metabolical markers and gyrB gene sequencing (A. Nemec, National Health Institute, Prague, personal communication). The remaining three Serratia sp.