Attached
Several Myrothecium isolates have been investigated
with respect to their ability to produce macrocyclic trichothecene esters. Myrothecium verrucaria CL-72 in liquid
culture produces roridin Hand isororidin E as the major
metabolites. M. ~oridum isolate 4582 produces no macrocyclic or trichoverroid trichothecenes, in solid or liquid
media but instead produces only simple trichothecenes, the
principal one of which is 7a-hydroxytrichodermol. On rice
substrate, M. roridum CL-514 (ATCC 20605) was found to
produce a new class of macrocyclic trichothecenes known
as roritoxins. The roritoxins (A-D) contain a tetrahydropyranyl ring fused to a y-lactone or lactol ring in the
macrolide sidechain and are analogous in structure to
vertisporin except that the roritoxins contain the
Z,E-diene system common to most of the macrocyclic trichothecenes. Roritoxin C is unique in that it possesses
a 9B,10~epoxide group which heretofore has never been
found naturally in trichothecenes isolated from fungal
sources. In liquid medium, M. roridum CL-5l4 (ATCC 20605)
produces yet another new antibiotic which was found to be
an isomer of epiepoformin and named as isoepiepoformin
«+)-(lR,5S,6R)-5-hydroxy-4-methyl-7-oxabicyclo[4.l.0)hept3-3n-2-one.)
Fermentation on rice substrate of a S. atra isolate
(Dl132) le~ to the isolation of trichoverrols A and B in
addition to the expected trichothecenes roridin E and
satratoxins F, G and H, strengthening the idea that trichoverrols A and Bare biosynthetic precursors to the
macrocyclic trichothecenes. The yields of satratoxins
also were greatly improved in this fermentation.
Verrucarin B, verrucarin J, satratoxin Hand trichoverrins A and B were isolated from a field sample obtained
from a house in suburban Chicago, Illinois, where the
occupants of the house were complaining of maladies
similar to those observed in trichothecene toxicosis. The
fact that trichothecenes were isolated from the field
sample itself and not from the laboratory growth of the
problem-causing fungus makes this isolation important.
Also this is the first time that stachybotryotoxicosis
has been reported in North America.
