Babes-Ernst Granules

BABES-ERNST GRANULES (Babes, Ernst), or metachromatic granules (synonyms: volutin, metachromatic granules, or polar bodies), are intracellular formations described by many authors, visible in unstained preparations due to their stronger light refraction, and in stained preparations due to their particularly strong affinity for basic aniline dyes. B.-E. granules form only on media containing phosphoric or nucleic acids. Their significance and nature are unclear. They have been described in typhoid bacilli, cholera vibrio, saprophytic bacilli, Spirillum volutans, etc. B.-E. granules are particularly important for distinguishing diphtheria bacilli from pseudo-diphtheria bacilli. For their study, the double staining method is recommended, where they appear either blue on a light brown background (with double staining: methylene blue with acetic acid + vesuvine) or red on a blue background (carbol fuchsin + methylene blue). Some researchers consider them homologous to centrosomes, or directing bodies, since they apparently participate in bacterial division.