Definition
Hygromycin B is a broad‑spectrum aminoglycoside antibiotic produced by the bacterium Streptomyces hygroscopicus. It is widely employed in molecular biology as a selective agent to isolate cells that have incorporated a hygromycin‑resistance gene.
Overview
Hygromycin B exhibits bacteriostatic activity against a range of Gram‑positive and Gram‑negative bacteria, as well as cytostatic effects on many eukaryotic cell types, including yeast, fungi, plant, and animal cells. Because eukaryotic cells are generally more sensitive to the compound than many bacterial species, hygromycin B is useful for selecting genetically engineered eukaryotic cells that express the hygromycin‑phosphotransferase (hph) resistance gene. The antibiotic is supplied as a white to off‑white crystalline powder, highly soluble in water and most aqueous buffers.
Etymology / Origin
The name “hygromycin” derives from the producing organism, Streptomyces hygroscopicus, combined with the suffix “‑mycin,” a conventional designation for antibiotics of microbial origin. The “B” distinguishes this particular compound from other related hygromycins (e.g., hygromycin A, C) that differ in their chemical structures and biological activities.
Characteristics
| Property | Description |
|---|---|
| Chemical class | Aminoglycoside antibiotic |
| Molecular formula | C₃₀H₅₆N₈O₁₃ |
| Molecular weight | ≈ 822.95 g·mol⁻¹ |
| Solubility | Highly soluble in water (≈ 100 mg mL⁻¹ at 25 °C) |
| Mechanism of action | Binds to the 30S ribosomal subunit, preventing translocation during protein synthesis; this halts elongation of nascent polypeptide chains. |
| Spectrum of activity | Inhibits growth of many bacteria (e.g., Escherichia coli, Staphylococcus aureus), yeast (Saccharomyces cerevisiae), fungi, and a variety of eukaryotic cells. |
| Resistance gene | The hph gene encodes hygromycin‑phosphotransferase, an enzyme that phosphorylates and inactivates hygromycin B, conferring resistance. |
| Typical usage concentrations | 100–400 µg mL⁻¹ for mammalian cell selection; 200–400 µg mL⁻¹ for yeast; 50–200 µg mL⁻¹ for bacterial strains lacking the hph marker. |
| Stability | Stable when stored as a dry powder at –20 °C; aqueous solutions remain active for several weeks at 4 °C, protected from light. |
Related Topics
- Aminoglycoside antibiotics – a class of antibiotics that target the bacterial ribosome, including streptomycin, kanamycin, and neomycin.
- Selectable markers – genes (e.g., hph, neo, bla) used to identify cells that have taken up foreign DNA in molecular cloning and transformation experiments.
- Antibiotic resistance – mechanisms by which microorganisms evade the effects of antibiotics; the hph gene is a classic example of enzymatic inactivation.
- Streptomyces hygroscopicus – the soil‑derived actinomycete that produces hygromycin B and other secondary metabolites.
- Protein synthesis inhibition – the biological process targeted by hygromycin B and other translation‑targeting drugs.
This entry reflects current, peer‑reviewed scientific knowledge as of 2026.