Nourseothricin (Streptothricin) Sulfate

Nourseothricin (Streptothricin) Sulfate is a broad-spectrum Streptothricin antibiotic and peptidyl nucleoside derived from Streptomyces noursei.  Structurally, itis a streptolidine ring bound through carbon 1 of a 4-o-acetyl,N-poly-lysinylated glucosamine.  It is used as a selection agent for genetically modified bacteria, yeast, plants, fungi, and protozoa.  The polycationic antibiotic is a mixture of several streptothricins, mainly D and F.  

 Nourseothricin (Streptothricin) Sulfate is soluble in water.   

CAS Number:96736-11-7

Molecular Formula: C₅₀H₉₂N₂₀O₁₈ • H₂SO₄

Molecular Weight:1359.46

Mechanism of Action:Nourseothricin Sulfate inhibits protein synthesis by inducing miscoding of mRNA.  It interferes with the outer membrane of Gram-negative bacteria by passing through the outer membrane very slowly via the porin pores.  

Storage Conditions:2-8 °C

Spectrum: Nourseothricin is a broad-spectrum activity against Gram-positive and Gram-negative bacteria.  It is also active against viruses, yeast (including C. albicans), viruses, fungi, mycobacteria, mycoplasma, and parasites.

Microbiology Applications:

Nourseothricin Sulfate is often used to select for cells with a mutation in the nat1 gene which encodes the enzyme nourseothricin acetyltransferase which confers resistance to Nourseothricin. It can be used in yeasts, bacteria, protozoa, plant cells, and filamentous fungi.

Resistant strains with a streptothricin-inactivating acetyl transferase have an additional protection system by way of a reduced penetrability of the outer membrane.  Researchers showed thaat strains could be rendered sensitive by damaging the barrier function of the membrane.

References:

Kochupurakkal BS and Iglehart JD (2013). Nourseothricin N-acetyl transferase: A positive selection marker for mammalian cells. PLoS ONE 8(7):e68509

Krügel H, Fiedler G, Haupt I, Sarfert E and Simon H (1988) Analysis of the Nourseothricin-resistance gene (nat) of Streptomyces noursei. Gene  62(2):209–217

Seltmann G (1992)  Resistance of Escherichia coli to Nourseothricin (Streptothricin): Sensitization of resistant strains by abolition of its outer membrane resistance.  Zent. fur. Bakteriol. 276(2):143-151