Classic Spotlight: How the Gram Stain Works

Classic Spotlight: Gram-Negative Bacteria Have Two Membranes.

The Danish microbiologist Hans Christian Gram developed a staining technique (1884) that classifies most bacteria into two large groups that are referred to eponymously, as Gram-positive and Gram-negative bacteria (1). His stain is still used in medical microbiology labs today, and because of its explanatory power, this classification is the most commonly used descriptor of a particular bacteri...

The Gram stain.

Ribonucleates and the Gram stain.

Salton (J. Gen. Microbiol. 30:223, 1963) summarized the evidence which demonstrates that the gram-positive cell is able to retain the crystal violet after iodine treatment because of the characteristic nature of its cell wall. This evidence is highly convincing, yet it does not explain the experiments of Henry and Stacy (Proc. Roy. Soc. London Ser. B 133:391, 1946) or of Bartholomew and Umbreit...

Classic Spotlight: Discovery of ftsZ.

Cytokinesis (cell division, fission, and septation) in bacteria is driven by a ring-shaped organelle containing dozens of distinct proteins. Among these, FtsZ plays preeminent roles in assembly and function of the organelle. FtsZ is also the first recognized cytoskeletal protein in prokaryotes and the likely progenitor of the tubulins. The discovery of ftsZ was inherently important. It also nic...

Comparison of bacterial antigen test and gram stain for detecting classic meningitis bacteria in cerebrospinal fluid.

The bacterial antigen test (BAT) screens cerebrospinal fluid (CSF) or other body fluids for antigens of classic bacterial meningitis pathogens (i.e., Streptococcus pneumoniae, Haemophilus influenzae type b [Hib], group B Streptococcus species, Neisseria meningitidis, and Escherichia coli K1) (7). The utility of the BAT has been questioned in several published reports (2, 5, 6, 8, 12, 15). Furth...