Anti-C4 polyclonal antibody

Lankacidins are a class of polyketide natural products isolated from Streptomyces spp. that show promising antimicrobial activity. Owing to their complex molecular architectures and chemical instability, structural assignment and derivatization of lankacidins are challenging tasks. Herein we describe three fully synthetic approaches to lankacidins that enable access to new structural variability within the class. We use these routes to systematically generate stereochemical derivatives of both cyclic and acyclic lankacidins. Additionally, we access a new series of lankacidins bearing a methyl group at the C4 position, a modification intended to increase chemical stability. In the course of this work, we discovered that the reported structures for two natural products of the lankacidin class were incorrect, and we determine the correct structures of 2,18-seco-lankacidinol B and iso-lankacidinol. We also evaluate the ability of several iso- and seco-lankacidins to inhibit the growth of bacteria and to inhibit translation in vitro. This work grants insight into the rich chemical complexity of this class of antibiotics and provides an avenue for further structural derivatization.

BACKGROUND The red imported fire ant, Solenopsis invicta Buren, is one of the most successful invasive ants in the world. Previous studies indicated that benzyl acetate and prenyl acetate elicited significant electroantennography (EAG) response in S. invicta and exhibited as attractants at certain concentrations. In addition, the easy commercial availability, low cost, and low mammalian toxicity make acetate esters ideal candidates to screen for potential use in S. invicta control. RESULTS We examined the EAG and behavioral responses to 26 acetate esters in all castes of S. invicta. Our results demonstrated a large diversity of EAG tuning and behavioral responses to acetate esters in S. invicta. For linear alkyl acetate esters, EAG response was clearly affected by the carbon chain length of the alkyl group. Linear alkyl acetates with five to seven carbon chain length of the alkyl group elicited significant EAG response in S. invicta, whereas those with shorter (C1 to C4) or longer (C8 to C12) carbon chain lengths did not. Different substitutions also exhibited large variety of EAG and behavioral responses in S. invicta. CONCLUSION Our works explored the olfactory and behavioral response of S. invicta to structurally different acetate esters, and identified two potential fire ant attractants, pentyl acetate and tran-2-hexenyl acetate, and two potential repellents, hexyl acetate and cis-3-hexenyl acetate. These compounds may be useful in developing new products for fire ant management.