Bacteria

Abstract

The number of microorganisms classed under bacteria in the broad sense is of the order of 10³ and it would be presumptuous to make attempts at generalizing their membrane transport mechanisms. In fact, only about a dozen bacteria have been examined in greater detail in this connection and the transport properties of literally no single one of them are understood in their entirety. The selection of bacterial objects for study has been largely fortuitous and there is no certainty that the existing transport data are typical or representative for the whole group of bacteria. Thus, for instance, of the relatively sizable group of strict anaerobes none has been examined for its transport parameters although some novel mechanisms might be operative there. Still, the few better known species display some characteristics in common, in particular (1) the distinctly active character of all the transports studied, including those of monosaccharides, disaccharides, amino acids, organic acids, and inorganic ions, and (2) the definite association of the transport proteins with a genetic locus on the bacterial chromosome.