Ultrastructure of Butyrivibrio fibrisolvens: a gram-positive bacterium

Abstract

The cells of bacteria of the genus Butyrivibrio are universally described as being gram negative, and they produce an unequivocal gram-negative reaction in the standard staining procedure. However, their cell walls contain derivatives of teichoic acid, which are characteristic of gram-positive cells. In this study, the cell walls of two representative strains of Butyrivibrio were of the gram-positive morphological type, as seen by electron microscopy, but they were very thin (12 to 18 nm). The thinness of these cell walls may account for the tendency of these cells to stain gram negatively in the standard staining procedure. Ruthenium red staining revealed an extracellular structure surrounding cells of Butyrivibio sp. (strain C3). This structure was composed of individual "knobs" that sometimes mediated cell-to-cell adhesion in the culture.

Maceration of Clover and Grass Leaves by Lachnospira multiparus

“…3b) and bacteria associated with the cell walls of clover tissue (Fig. 3a) showed that the cell wall of these cells was of the grampositive morphological type (9). However, overnight cultures of Lachnospira D25e constantly stained gram variable.…”

Architecture and assembly of the Gram‐positive cell wall

“…Fragmenting sacculi resulted in circumferential tears and patches, but not 50 nm cables. It is also known that Gram‐positive peptidoglycan thickness can be modulated, becoming both thicker (Hanaki et al ., ), and thinner (Cheng and Costerton, ), at odds with discrete coiled cables that would always have substantial diameters due to the stiffness of glycan strands. It is further unclear how peptidoglycan cables could be assembled prior to incorporation into the sacculus in the absence of a consistent and large periplasmic space, and no 50 nm gaps were seen in cell walls or sacculi corresponding to the insertion points of new cables.…”

Subcellular fractionation of the Gram negative rumen bacterium, Butyrivibrio S2, by protoplast formation, and localisation of lipolytic enzymes in the plasma membrane

“…With certain exceptions it has been found necessary with Gram negative organisms to perturb the structure of the outer membrane of the cell envelope by the application of EDTA in order to facilitate penetration by lysozyme and digestion of the underlying peptidoglycan (Birdsell & Cota-Robles 1967;Kaback 1971;Salton 1976). An ultrastructural study of 2 strains of Butyriuibrio (Cheng & Costerton 1977) Similarly. electron microscopy of sectioned ihrio S2 cells has revealed the absence of a trilaminar outer membrane and an envelope morphology characteristic of a Gram positive rather than a Gram negative cell type.…”

“…The limited susceptibility to lysozyme action may be related in some way to the Gram negative character of the bacterium but this feature is most probably due to a physical property of the cell wall. Cheng and Costerton (1977) drew attention to the Gram positive morphology of two strains of Butyrioibrio fibrisolr c m and speculated that the thinness of the cell wall contributed to the anomalous Gram reaction. It had been shown earlier that B. fibro-so1t~en.s contains lipoteichoic acid and glycerol teichoic acid (Sharpe et a/.…”