ABSTRACT

The presence of the pili, or the male specificity of bacteria, appeared as one of the basic physiological features of the single-stranded RNA phages and stimulated active studies of the bacterial pili that led to the broadening of the lists of existing pili, their classification and clear understanding of their structure and function. This chapter concentrates on microbiology and describes the RNA phages from the point of view of the bacterial hosts and their pili. It is intended to unveil the interaction of the RNA phages with different pili, describing the genetics and variability of the latter. Moreover, it is intended to explain how pili work, what are incompatibility groups and why only four bacterial families, Enterobacteriaceae, Pseudomonadaceae, Caulobacteraceae, and Moraxellaceae, are known as hosts for the RNA phages. The interplay of the RNA phage infection and bacterial conjugation is lighted up. Current progress in the elucidation of the fine structure of the pili is demonstrated.