Download Diagram B Protoperithecial parent

Diagram
B
Protoperithecial
I
CI,
parent
X
the
reasserted
h&-2+
2
o,
ad-6
pan-2+
Furthermore,
it
addition
heterocoryon
hove
assortment
in
Curtis,
C.
sability’
This
noted
conidial
been
prototroph
that
the
pan-2
gives
rise
to
prototrophs
X
106
parent,
9.4
The
recovered.
Studies
on
the
parent
results
---Biology
recessive
pal-2+
is stable
in
viable
of
type
of
Yale
heterokaryon
detected
by
on
the
complete
1953)
Using
the
on
via
only
lethals
Six
origin-1
be
medium.
Its
and
I8 total
interfere
with
the
Research
Unit,
Johnson,
Jane
growth
genetic
Acad.
for
and
mitotic
Sci.
detecting
no
re-
They
tested
for
39,
lO27-
mui;;ts
which
used
marker.
then
cross
for
medium.
W.
and
in
the
lethols
of
M.
Neurospom
-
#I,
on
o
Lethals
were
supplementability
Srb
Isolation
of
isolates
after
heterokaryotic,
the
exceptional
crosses
ore
in
spores
N.
provides
crosso
or
greatlyxcilitated
-shows
the
buckcrosses
frequency
of
pk
-
of
to
N.
if=e
parent
osci
containing
wild-type
N.
-
at
one
of
supplementation
the
of
of
the
nitrous
one
total
strand
lethal5
nucleus
in
WCS
the
locus.
which
were
of
affect
components
nutrients
Leupold
case
o complementary
interaction
cases
of
are
the
complete
known
found.
to
---
Mutagenesis
Scotland.
normally
a population
sitophila.
been
to
and
in
unmarked
mutagenic
i.e.,
if
-than
spon-
presumably
only
the
its
induced
Horowitz
which
6 single
the
colonial
ascorpaes
spores
of
rare.
has
Neurospora,
likely
these
have
is crossed
bisexual
acid
argument
supplementable,
relatively
acid
in
nitrous
of
When
tetrasperma.
nitrous
is similar
Since
be
ore
of
each
Edinburgh,
homo-
that
1962),
due
to
particularly
among
be
smaller,
large,
the
seem
must
No
Genetics,
small,
effect
its
arginine.
might
tested
proved
lethals
proportion
and
for
mutation
auxotrophs.
Animal
If
would
tested
be
medium
were
certain
showed
Newsletter
to
none
1960)
from
This
induced
complete
Adrian
base.
were
found
and
spontaneous
o higher
1951).
the
of
production
spores
generation
Not.
complete
were
tested
supplementable,
lethal5
on
of
Institute
be
was
was&
B of
RNA
Neurospora
requirement
Accordingly
tetraspermo
(Proc.
this
the
Connecticut.
morphological
They
London,
65-74,
Gyes,
heterokoryon
the
from
Haven,
and
utilizing
evidence
o method
o recessive
were
material,
to
16,
Non-supplementability
from
New
on
supplementable
o single
expected
lethals
mosaics
lethals
that
of genetic
Symp.,
mosaic
DNA.
karyotic
carrying
no
mutation,
time,
plated
give
Mukai
reverse
present
been
thus
devised
homokoryons.
Microbial.
of
orea
might
supplementable.
Gen.
deomination
Harbor
induced
The
nuclei
marked
finding
Sot.
o%oII
Spring
acid
its
I9 spontaneous
Mukoi’s
Symp.
TMV
covers
(Cold
of
of
system,
and
(10th
taneous
of
some
Atwood
Gierer
it
one
hove
grow
of
the
medium.
confirming
effect
with
At
test
and
35,
non-appearance
incapable
University,
Atwood
‘dispen-
lethals.
and
selfings.
oscospores
this
Department,
not
adenine.
cannot
balanced
would
require
parent
Neurosporo.
F.
of
be
neither
os the
prototrophs
would
adenine.
should
that
2
hist-2+
ylo+,
prototroph
require
in
I or
ad-6+
ylo+,
This
parents
mutant
into
N.
are
Greed
N.
genetically
in o cross
includes
small,
homokoryotic
tetrosperma.
high
spores
when
Consequently,
of
c&parable
easily
peak
spores
These
distinguishable
reproduces
to
kinds
cross~l
homokaryotic
frequency.
ore
tetrasperma
certain
the
Neurosporo
small,
with
homokaryotic
formed
pk-2
-
tetrasperma,
of
random
sexually.
oscospore
genetic
work
with
-
N.
gene.
in o series
of
12th
and
13th
Table
% ofasci
with
more than 4 spores
No. of asci
observed
Parents
I
Small spores 05
% of total spores
I.
+,Ax+,a
I, 165
0.86
0.43
2.
+,Ax&a
I, 013
21.72
14.62
3.
+,a~&,,
918
32. 90
22.81
4.
f,
49.55
41.00
5.
+, +, A x +, 4,
0.46
0.23
+, A x J&,
&,
1,011
o
o
214
In the crosses designated
4 and 5, one
ting in --N. crow
and the mating
type
first transferred
to N. sitophila
by on
into - N. tetrospermc
---Department
of the parents
includes
o purple-denine
requiring
gene originoallele
a from N. sitophila.
The marker genes from N. crosso were
interspecific
crossfollowed
by back-crossing,
and Grethencrossed
of Plant Breeding,
Cornell
University,
Ithaca,
New York.
Kihora,
May.
Nuclear
number in
germinating
conidia
of Neurospora.
A study of the nuclear
division
time in Neurospora
crow
conidia
is reported
here.
The problem
was first
approached
by o cytological
method;
namely
doing o
nuclear
stain and counting
the number of nuclei
per conidium.
The culture,
wild-type
3. la, was grown
on either
complete
or minimal
slants for at least 5 days, then conidia
were transferred
to o liquid
minimal
medium
in which
they were grown at 25’C for the desired
length of time with samples taken at one-half
hour intervals.
The cells were then centrifuged,
washed
and stained
using o Giemsa
nuclear
stain.
No.
Cells from
Minimal
slants
Cells from
Complete
slants
of nuclei
per conidium
(percent
of total
cells)
I
2
3
4
0 time
l/2 hour
I hour
I l/2 hours
2 hours
33.6
36.6
34.5
30.0
26.3
49.0
47.0
47.0
44.5
48.0
13.5
12.0
14.3
15.4
17.0
3.6
3.4
3.0
5.6
5.4
0 time
l/2 hour
I hour
I l/2 hours
2 hours
32.3
39.0
34.6
32. 3
34.0
49,o
44.6
48.0
47.5
44.3
15.0
II.7
13.0
15.0
16.6
2.8
3.5
3.0
3.7
3.8
It was found that there is no appreciable
difference
in the number of nuclei
per conidium
between
cultures
grown on minimal
and complete
medium
in contrast
to the report by Huebschmon
(Mycologia,
Sept. -Oct.
1952) that cultures
grown on complete
medium showed about twice (IS many nuclei
per conidium
os those grown on minimal
medium.
There was an indication
that those grown on complete
medium develop
germ tubes at an earlier
time than those grown on minimal
medium.
During
the period
of observation,
however,
these conidia
formed germ tubes with no detectable
nuclear
divisions.
By the technic
used here it was not possible
to get o precise
meawe
of the nuclear
division
time.
The
nuclei
underwent
o cycle of change
in appearance.
The stained
nuclei
from resting cells were discrete
and compact.
After one hour in culture
they became very granular
and diffuse.
After two hours in culture
they regained
the discrete
appearance
of resting
nuclei.
It appears as if the nuclei
were preparing
to
divide
after I hour in the growth
medium,
however
no corresponding
increase
in the number of nuclei
per