s - Mycological Society of America

P. L. SKATRUD, J. HOSKINS, J. D. WOOD, M. B. TOBIN
and S. W. QUEEKER. Lilly Research Laboratories,
Lilly Corporate Center, Indianapolis, IN 46285
Genetic manipulation of the $-lactam antibiotic
biosynthetic pathway.
The p-lactam antibiotics, which include the
penicillins and cephalosporins, all share certain
structural features, a similar mode of action and
a lov toxicity profile. Recently, several genes in
the biosynthetic pathways leading to b-lactam
production have been cloned and characterized. As
a result of these studies, specific rational
alterations of the biosynthetic pathway in
industrially-important . . producing - organisms -
.JCephalosporium acremonium and Penicillium
Phrysogenum) are now possible. Three specific
applications of genetic alteration of the
biosynthetic pathway will be discussed: 1. Gene
dosage studies leading to increased overall
productivity. 2. Gene disruption studies leading
to inactivation of specific genes. 3. Expression
of a foreign gene in the $-lactam producing fungus
- P. chrysogenum leading to production of an altered
$-lactam structure in fermentation.
-- K.T. - SMITH. USDA Forest Service, P.O. Box 640, Durham, NH
03824. The moisture content of wood is altered by Postia
placenta and Trametes versicolor early in the decay process.
The wood
-
decay process requires appropriate levels of moisture
and aeration. The decay fungi are capable of altering
these levels. Various combinations of decay fungi and wood
species were tested to determine their effect on wood moisture
content (MC). Decay cnambers were french-square bottles,
each containing an agar culture of either the brownrot
fungus placenta (Fr.) M. Larsen & Lombard, the
whiterot fungus Trametes versicolor (L:Fr.) F'ilat (syn. Coriolus
versicolor (L.:Fr.) Quel.!, or uninoculated agar. Oven-dried
wood samples (5 x 10 x 50 mm, radial: tangential: longitudinal)
were prepared from hardwood and softwood trees differing
in decay resistance and were placed in the cham- .
bers. Within one or two weeks of incubation, the brownrot
fungus caused greater increases in wood MC than did the
whiterot fungus. Both fungi increased wood MC above that
of the uninoculated controls. This pattern was maintained at
12 weeks of incubation and was correlated with the severity
of decay measured as percent weight loss. Across the tree
species tested, as wood increased in decay resistance, the
ability of the fungi to wet the wood decreased. In some fungus
and wood combinations, wood MC may have become
sufficiently high to limit the aerobic respiration of the wood
by the fungi. This possibility draws attention to the need for
the careful choice of appropriate experimental conditions to
test comparative decay resistance.
M.L. SMITH and J.B. ANDERSON. Dept. of Botany.
University of Toronto, Erindale College. Mississauga.
Ontario, Canada L5L 1C6
Mitochondria1 genetics in a natural population of
Wc have examined the transmission and propagation of
mitochondrial genotypes in natural clones of asmill aria
at a nonh Michigan hardwood forest study site. Through
an analysis of mating-type alleles we have determined
that therc are two A. bulbosa clones. each exceeding 500
m diameter, at the sitc. In addition. there are several
smaller A. DsIoYae clones within a 9,000 m2 red pine
plantation, locatcd within the hardwood stand. Based on
rcstriclion fragment length polymorphisms (RFLPs)
each vegetative clone at the site has one. unique
mitochondrial DNA type. In contrast, a diploid mycelium
arising from a compatible laboratory mating of haploid
monokaryons , contains mitochondria from both parents
since nuclei, but not mitochondria, migrate
bidirectionally. Experiments now underway are
designed to dctermine the nature and origin of
intraspecific variation of the mitochondria1 genome in
Arm i l l ari a species. Through RFLP and nucleotide
sequence analysis we are attempting to detect intraclonal
polymorphisms between distant regions of the very old
(ca 400 to 900 yrs) A. bulbosa clones at the Michigan site.
By comparing RFLP maps from several A. Dstovag clones,
we will determine where mutations are likely to occur in
thc mtDNA molecule.
Fred S~iesel, Department of Botany and
Bacteriology, University of Arkansas,
Fayetteville, AR 72701.
Evening Discussion I. Federal Funding for
Mycological Research. James Rodman,
Systematic Biology, National Science
Foundation, Washington, DC. Fundinu Throush
the NSF. David Malloch, Department of
Botany, University of Toronto, Toronto,
Ontario, Canada. Fundins Throuuh NSERC. A
Canadian Point of View. Harold Keller,
University of Texas, Arlington, TX. what to
EXDeCt of Your S D O ~ S Prourams O ~ ~ ~ Office. A
representative, NIAID, Division of
Microbiology and Infectious Diseases,
Beltsville, MD. Fundinu Throuqh the NIH.
F.W. SPIEGEL. Department of Botany and
Microbiology, University of Arkansas,
Fayetteville, AR 72701.
Revision of the genus Protostelium.
The mycetozoan genus Protostelium contains
six described species: P. mycopha~a, 2.
nocturnum, P. irre~ularis, 2. expulsum, z.
pvriformis, and 2. arachis~orum. All these
organisms meet the present morphological
criteria for inclusion in the genus. That
is, they all have a trophic state that
consists of uninucleate, nonflagellate
amoebre, and they all have sporocarps which