Proper Expression

Please never make these mistakes!

Latin words: medium/media, bacterium/bacteria

If you prepare a litre of LB, you are actually preparing a litre of Lysogeny Broth. So don't ever claim that you prepare "LB broth". But this is not what I actually want to say, after all, broth is not a latin word. It's about something else. A mistake that you find again and again, in the nicest publications: peole don't know how to handle latin words, because they never learned the language. So they don't know that words ending with -um are nouns with the gender neuter. And they are singular. The plural of such a noun ends with -a. All those nutritious and less nutritious liquids we grow bacteria in are media. Because there are several of them. Media is the plural of medium. It's "one bottle of growth medium" and not "one bottle of growth media". The same holds true for bacterium and bacteria. Never ever talk about this "phage that adsorbs to a bacteria". Never.

Greek words

And then there is the difference between adsorption and absorption.

Absorption generally refers to two phenomena which are largely unrelated. In one case, it refers to when atoms, molecules, or ions enter some bulk phase - gas, liquid or solid material. For instance, a sponge absorbs water when it is dry. And it refers to the the process by which the energy of a photon is taken up by another entity, for example, by an atom whose valence electrons make transition between two electronic energy levels. The photon is destroyed in the process. The absorbed energy may be re-emitted as radiant energy or transformed into heat energy. The absorption of light during wave propagation is often called attenuation. The tools of spectroscopy in chemistry are based on the absorption of photons by atoms and molecules. So whenever you measure the turbidity of a bacterial culture in the spectrophotometer, you actually measure how much light this culture absorbs. If its optical density (OD) is high, it absorbs a lot of light.

Adsorption is similar, but refers to a surface rather than a volume: adsorption is a process that occurs when a gas or liquid solute accumulates on the surface of a solid or, more rarely, a liquid (adsorbent), forming a molecular or atomic film (the adsorbate). When working with phage, it means that phage particles attach to the cell surface. They can't be found anymore in the medium. Phage adsorb to cells. It looks as if cells have absorbed phage, but this is wrong. Cells are not sponges that soak up phage (you can't squeeze the particles out of the cell later on, the particles cling to the surface and eject their DNA content into the cell).

Phage & Phages

For some reason, people think (me included), that the plural of phage is phage. There is no clear justification for this (see here). So it's actually simple: phage is singular, phages is plural. "The genome of phage HK022 is mosaic-like" and "a concentration of 10⁶ pfu/mL may correspond to many more viable phages."