More information: Çağatay Işıl et al, Virtual Gram staining of label-free bacteria using dark-field microscopy and deep learning, Science Advances (2025). DOI: 10.1126/sciadv.ads2757.

In this simplified diagram of gram staining, bacterial cells are first treated with a purple dye called crystal violet. The dye gets into the cells’ peptidoglycan layer (gray), tinting it purple.

Gram-positive bacteria are bacteria with thick cell walls. In a Gram stain test, these organisms yield a positive result. Here’s why knowing whether the result is positive or negative is important.

Gram staining is one way scientists can identify bacteria. Gram-positive bacteria, such as Staphylococcus, appear blue or purple under a microscope when scientists apply a stain. Conversely, Gram ...

The main benefit of a gram stain is that it helps your doctor learn if you have a bacterial infection, and it determines what type of bacteria are causing it. This can help your doctor determine ...

Gram negative bacteria. Gram negative bacteria appear a pale reddish color when observed under a light microscope following Gram staining. This is because the structure of their cell wall is unable to ...

The Gram staining was first developed by a Danish scientist, Christian Gram, in 1884 and it has been used so far as the golden standard to classify bacteria. However, it has several obstructions.

Gram staining is a type of differential staining used to distinguish between Gram positive and Gram negative bacterial groups, based on inherent differences in their cell wall constituents. Credit ...

But what are the differences between gram-positive and gram-negative bacteria? The names themselves date back to 1884, when Danish bacteriologist Hans Christian Gram developed a staining procedure ...

Being able to differentiate bacterial species is important for a host of reasons. While molecular techniques can determine the specific species, even without getting into the molecular nitty gritty, ...