aii
r
agi.
—.
dletitned
Bini, eves»
faite Eneatae 8
‘
Page 355
Radioresistance of Fish ”
etait
F
for fish, or to metamorphosis
(Snedelization tohatenigsions were calculated
tion. The
for amp
.
logarit hmic transforma
regression coefficients,
Cor 1956) eervat ions, the
rmined from the value of
dete
s
itie
abil
prob
the
Sod
e (Table 6).
summarizing tabl
“1 appear ina
ANALYSIS OF PUBLISHED RESULTS
eggs of rainbow
welander (1954) irradiated the stage
s from
us
vario
in
)
nerii
gaird
trout (Salmo
1
Table
his
From
.
stage
yed
ate-e
F one-cell tol
as
50
dosel
letha
e
relat
to
ble
E gnd 2 1t 18 possi
about two months
and
Ee geterzined both at hatching
ption to per~
ai the completion of yolk absor :
Rugh and Clugston (1955) described the effects
of x-radiation upon various stages in the embryonic
development of Fundulus heteroclitus. Although the
lethal dose-50 is not stated, their descriptions of
results permitted our estimating the lethal dose-50
(Table 3)
trends.
Table 3.
Letnal dose~50's were also estimated from
der's (1954, page 235) graphs, and both calare used in
welated and estimated !ethal dose-50's
Table 2 and Figure 3.
Table 2.
Lethal dose-50 of rainbow trout
at six stages of incubation,
L
Fo
incubation
when
At hatching
‘Birradiated
Stage irradiated
———
Name
Per cent
or
of incu-~
number
bation
.28
2.54
17.3
25,
67.
78
468
524
735
-
89.
calculatedlestimated
80
600
700
1,000
3,000
-
58
313
461
454
415
4,000
70
400
600
500
600
904
1,000
lvethal dose-50's calculated by Welander (1954, page
T
T
(roentgens)
2- to
8-cell
1.90 -Only slightly less sensitive
than l- to 2-cell; 500
roentgens permitted quite
normal development...........
5.30 -1,000 roentgens permitted
only a few to hatch..........
when controls at stage 22....
ll;,expanding
blastula
8-day
72.8
embryo
400
600
800
-Tolerated up to 3,000
roentgens without a marked
decrease in the number developing normally............ 3,000
4,000
T
AT HATCHING
1,000 |
Effect
1.14 -300 to 400 roentgens resulted in stunted, but otherwise normal development :600
roentgens ,25 per cent hatched,
stunted; reached stage 15
233) .
4,000
Estimated
lethal
dose-50
at hatching
1- to
2-cell
At end of yolk stage
calculatedlestimated
Responses of embryos of Fundulus heteroclitus
to X-irradiation, from Rugh and Clugston,
dose-50 based upon their descriptions.
lethal dose-50 in roentgens
me Per cent of
;
(1955), with subjective estimates of lethal
; se tage .of incubation reached at the time of irra-
diation.
at four stages which can be converted to
percentage of the total incubation period (11 days)
using the time-table of embryonic development contributed by Solberg (1938). Table 3 and Figure 4
give the trend of embryonic radioresistance of
Fundulus which closely resembles the preceding
a
wn
z
4 7
qt«
4
©1,000}
7
2
ui
Qo
x
mw”
&
o
z
100}
4
z=
nt
las
100+
7
Qo
Lad)
a
o
a
z
°
-/
1d
oa
i
i
1
7
7
F
=
x
Eud
a!
wm
1
us
o
© 1,000 |
AT END OF YOLK STAGE
_
>.
La
<=
x
=
9
“i
ot
oF
|
;
4
oe
.
10
100
PER CENT OF INCUBATION WHEN IRRADIATED
.
Figure 3.
Re lationshi p of let
hal dosete Per cent of
incubation of rai
nbow t
“8 when itrrag
ra
1954)
Leth 1
at
solid lin
o
e te stage (lower
).
CirCu
wore
cles
: ana
tine »
Based on Calculate
ae.
d lethal dosese@ and troken
lines
based
Mated lethal dos
e-50's
“eon
.
’
*
100
and broken line; and of lethal dose-50 to per
cent of time from fertilization to metamorphosis of amphibia (Rugh, 1954), circles
and solid lines.
I
‘
t
\
Id
PER CENT OF DEVELOPMENT WHEN IRRADIATED
Figure 4.
Relationships of lethal dose-50
to per cent of incubation of the eggs of
r
eo
x
o
Ot
Fundulus (Rugh and Clugston, 1955), crosses
stro
ee eae
too -
10
.
a
.
Belyaeva and Pokrouskaya (1957, 1958) reported
for the loach, (isgurnus fossilis, that anaphasetelophase was the most sensitve mitotic phase, 20
times as sensitive as interphase, and that radio-
resistance rose with advancing embryological development.
From their description of results, le-
thal dose 50's may be roughly estimated for four
stages (Table 4), but, because of the high resistance at last blastula, variability is tvo great for
statistically significant regression (Table 6).
Rugh (1954) described the results of irradiat-
ing amphibia at various stages from the uterine egg