ABSTRACT
The fungal strain INA 01108 producing antibiotic substances with broad spectrum of antibacterial activity was isolated from the natural environment. By the morphological characteristics and DNA analysis it was shown to belong to Ascomycetes of Sordariomycetes. In submerged culture the strain produced at least four antibiotics. The major component of them was identified as eremophilane-type sesquiterpene eremoxylarin A. Eremoxylarin A is effective in vitro against grampositive bacteria, including methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin group glycopeptide antibiotics resistant Leuconostoc mesenteroides VKPM B-4177. The efficacy and toxicity of eremoxylarin A was determined on a murine staphylococcal sepsis model. The dose of 6.25 mg/kg provided 100% recovery and survival of the animals, while the dose of 3.12 mg/kg was close to the ED50. The chemical structure of eremoxylarin A allows to modify the antibiotic and such studies may be relevant to design a less toxic derivative without loss of the valuable antimicrobial properties.
Subject(s)
Anti-Bacterial Agents/therapeutic use , Ascomycota/growth & development , Leuconostoc/drug effects , Methicillin-Resistant Staphylococcus aureus/drug effects , Sepsis/drug therapy , Sesquiterpenes/therapeutic use , Staphylococcal Infections/drug therapy , Animals , Anti-Bacterial Agents/isolation & purification , Anti-Bacterial Agents/toxicity , Ascomycota/metabolism , Ascomycota/ultrastructure , Disease Models, Animal , Dose-Response Relationship, Drug , Drug Resistance, Bacterial/drug effects , Mice , Microbial Sensitivity Tests , Polycyclic Sesquiterpenes , Sepsis/microbiology , Sesquiterpenes/isolation & purification , Sesquiterpenes/toxicity , Staphylococcal Infections/microbiologyABSTRACT
Long-term microbiological investigation of the pollen of silver birch (Betula pendula) in the Mos- cow, and Moscow region areas revealed that: almost one-third of the analyzed samples, contained the fungus identified by morphological, cultural, and molecular genetic techniques as Quambalaria cyanescens (de Hoog & G. A. de Vries) Z.W. de Beer, Begerow & R. Bauer. This species was previously known mostly as a syrmbiont of tropical plants of the generaEucalyptus and Cortyminbia and has not been isolated in Russia. We revealed a close association between Quambalaria cyanescens and silver birch. The micromycete was regulaly detected in pollen samples, as well as on the.inside and outside of the aments, on the surface of leaves and branches. It was never isolated from other plant species in the investigated area. The data on the morphological and cultural characteristics of the fungus, its cell ultrastructure, and occurrence are presented, as well as the phylogenetic analysis of the isolated strains.