Location: Renewable Product Technology ResearchTitle: Polyols, not sugars, determine the structural diversity of anti-streptococcal liamocins produced by Aureobasidium pullulans strain NRRL 50380
|MANITCHOTPISIT, PENNEPA - Illinois State University|
Submitted to: Journal of Antibiotics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/10/2016
Publication Date: 7/20/2016
Publication URL: https://handle.nal.usda.gov/10113/5832875
Citation: Price, N.P.J., Bischoff, K.M., Leathers, T.D., Cosse, A.A., Manitchotpisit, P. 2016. Polyols, not sugars, determine the structural diversity of anti-streptococcal liamocins produced by Aureobasidium pullulans strain NRRL 50380. Journal of Antibiotics. 70(2):136-141. doi: 10.1038/ja.2016.92.
Interpretive Summary: Liamocins are a new type of polyol-lipids made by the soil-fungus Aureobasidium pullulans. The known liamocins have a mannitol head-group linked to 3,5-dihydroxy-decanoate fatty acid chains, 3 or 4 of which are joined by polyester bonds. Some also contain acetate groups. We have now found that other liamocins are made by Aureobasidium dependent upon the choice of strain and growth conditions. We found that growth on different polyols, but not sugars, resulted in considerable structural variation including liamocins with galactitol, sorbitol, D-arabitol, D-xylitol, and D- or L-threitol headgroups. Several of these new liamocins were purified, and tested for their anti-bacterial activity. Like the known liamocins the new compounds are highly selective against Streptococcus bacteria and much less so against Staphylococcus, Enterococcus, or Bacillus species. We conclude that the liamocin variants are a new type of antibiotic that could be used to selectively control Streptococcus bacteria.
Technical Abstract: Liamocins are polyol-lipids produced by the fungus Aureobasidium pullulans, and have selective antibacterial activity against Streptococcus species. Liamocins produced by A. pullulans strain NRRL 50380 on sucrose medium have a D-mannitol head-group ester linked to 3,5-dihydroxydecanoate acyl chains, three or four of which are joined together by1,5-polyester bonds (liamocins Man-A1 and Man-B1), and similar 3'-O-acetylated analogs (Man-A2 and Man-B2). However, other types of liamocins are produced depending on the choice of strain and growth conditions. In the current study, growth on different polyols, but not sugars, resulted in considerable structural variation, including liamocins with D-galactitol (dulcitol), D-sorbitol (glucitol), D- and L-ribitol, D-xylitol, L-threitol, and glycerol headgroups. The headgroups of liamocins produced on arabitol were shown to be entirely composed of D-arabitol. These liamocin variants were structurally characterized by NMR and mass spectrometry, and tested for antibacterial activity. The new liamocin variants also had selective activity against Streptococcus. Liamocin structural variants are novel antibacterials against Streptococcus sp. that merit further investigation.