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Nuclei of Arbacia and Chaetopterus eggs as photographed by infrared light
398 NUCLEI
OF ARBACIA AND CHAET0PTERUS EGGS AS PHOTOGRAPHED BY INFRARED LIGHT E. B. HARVEY
Marine
Biological
and
G. K LAVIN
Laboratory, Woods Hole, Mass., Biological Laboratory, Princeton University, and Rockefeller Institute for Medical Research, New York City
N. J.,
Received December 1, 1950
has been found previously by these writers that the red pigment granules in the Arbacia egg and pluteus do .not show in photographs taken with infrared light. It was therefore thought that cleavage figures photographed with infrared light might be of interest. Such proved to be the case. With visible light (Figs. 1, 3, 5, 7), the red pigment obscures the nuclei and division figures, but when photographed with infrared light, these stand out with remarkable clearness as white areas against the dark background of the cytoplasm. The streak stage of the early prophase (Fig. 2), the dumbbell shaped mitotic figure of the metaphase, the separated spheres of the telophase, and the two nuclei and division plane following first cleavage are clearly shown (Fig. 4). Likewise one may clearly see the mitotic figures and division planes of subsequent cleavages (Fig. 6). In the early and late blastulae, the nuclei stand out with great clearness; in fact one can actually count the numbers of nuclei present in an optical section at various stages and calculate the numbers present in the whole egg (Fig. 8). This method might prove of value in relating chemical changes in the developing egg with progressive cleavages. The nuclei in the red half egg which are present after fertilization of the non-nucleate half (1, 2, 4) can be seen much more clearly than with visible light, both as a single nucleus soon after fertilization and as two or more nuclei after its division (Figs. 9, 10, 11). It will be of interest to study photographs of the parthenogenetic merogones (developing non-nucleate parthenogenetic half-eggs) with infrared (2, 4).
IT
Plate Fig. Fig. Fig. Fig.
1. 2. 3. 4.
I (Magnif.
280 x ).
Ar6acia pu,thdata, streak stage, 30 minutes after fertilization, Same, infrhred light. Spindle stPge and just after cleavage, 45-60 minutes after Same, infrared light.
visible
light.
fertilization,
visible
light.
Nut -1ei photographed by infrared light Visible
ARBACIA
399 Infrared
E. B. Harvey and G. I. Lavin
400 Visible
Fig. Fig. Fig. Fig.
5. 6. 7. 8.
ARBACIA
infrared
Plate.‘11 (Magnif. 280 x ). puncfulata, 4-ceil s&age, 1 l/z hrs. after fertilization, visible light, Same, infrared light. Blastulae, 3-4 hrs. after fertilization, visible light. Early and late blastulae, 3-8 hrs. after fertilization, infrared light.
Arbocin
Nuclei photographed by infrared light Visible
Infrared ARBACIA,
red
half-egg
CHAETOPTERUS,
Plate Figs. 9-11, magnif. 250 X; Figs. 12, Fig. 9. Arbacia punctulata, red half, Fig. 10. Same 2 hrs. after fertilization. Fig. 11. Arbacia pmcfulata, red half, Fig, 12. Chaefopferus pergamenfaceus, Fig. 13. Same, infrared light.
fertilized
unfertilized
III.
13, magnif. 300 x. 20 minutes after fertilization, 20 minutes-2 unfertilized,
visible
hrs. after fertilization, visible light.
light. infrared
light.
402
E. 13. Harvey and G. I. Lavin
The Chaetopterus egg, when viewed or photographed with ordinary light (Fig. 12) is quite opaque, and not much structure can be seen (3). In the infrared photographs the granular structure of the cytoplasm is seen, and the nuclear material of the unfertilized egg appears as a brilliant white area (Fig. 13). The general configuration of mitotic figures and nuclei is brought out by infrared because of its great penetrating power, especially through the red pigment granules. The detailed structure of the spindle and asters is not brought out by infrared because of its relatively poor resolving power. It is also owing to this that we do not see the fine granules in the cytoplasm, but only the coarser granules, as is evident in most of the photographs. TECHNIQUE
The eggs were photographed by the use of Kodak Infrared Sensitive plates. The developer was D 19. A tungsten microscope lamp was the light source. An image was arranged and focussed with a deep red light filter (Wratten 24 A) after which an infrared transmitting light filter (Wratten 88 A) was substituted for the photography. SUMMARY
Photographs, taken with infrared light, of all stages of dividing Arbacia punctulata eggs show the configuration of mitotic figures and nuclei as brilliant white areas against the dark granular cytoplasmic background. The photographs are very different from those taken with visible light. The nucleus and cytoplasm of the unfertilized Chaetopterus pergamentaceus egg which are quite opaque with visible light are quite striking with infrared light. REFERENCES 1. 2. 3. 4.
HARVEY, E. B., Biol. Bull., 62, 155 (1932). Biol. Bull., 71, 101 (1936). --Biol. Bull., 76, 384 (1939). Biol. Bull., 79, 166 (1940).
OF ARBACIA AND CHAET0PTERUS EGGS AS PHOTOGRAPHED BY INFRARED LIGHT E. B. HARVEY
Marine
Biological
and
G. K LAVIN
Laboratory, Woods Hole, Mass., Biological Laboratory, Princeton University, and Rockefeller Institute for Medical Research, New York City
N. J.,
Received December 1, 1950
has been found previously by these writers that the red pigment granules in the Arbacia egg and pluteus do .not show in photographs taken with infrared light. It was therefore thought that cleavage figures photographed with infrared light might be of interest. Such proved to be the case. With visible light (Figs. 1, 3, 5, 7), the red pigment obscures the nuclei and division figures, but when photographed with infrared light, these stand out with remarkable clearness as white areas against the dark background of the cytoplasm. The streak stage of the early prophase (Fig. 2), the dumbbell shaped mitotic figure of the metaphase, the separated spheres of the telophase, and the two nuclei and division plane following first cleavage are clearly shown (Fig. 4). Likewise one may clearly see the mitotic figures and division planes of subsequent cleavages (Fig. 6). In the early and late blastulae, the nuclei stand out with great clearness; in fact one can actually count the numbers of nuclei present in an optical section at various stages and calculate the numbers present in the whole egg (Fig. 8). This method might prove of value in relating chemical changes in the developing egg with progressive cleavages. The nuclei in the red half egg which are present after fertilization of the non-nucleate half (1, 2, 4) can be seen much more clearly than with visible light, both as a single nucleus soon after fertilization and as two or more nuclei after its division (Figs. 9, 10, 11). It will be of interest to study photographs of the parthenogenetic merogones (developing non-nucleate parthenogenetic half-eggs) with infrared (2, 4).
IT
Plate Fig. Fig. Fig. Fig.
1. 2. 3. 4.
I (Magnif.
280 x ).
Ar6acia pu,thdata, streak stage, 30 minutes after fertilization, Same, infrhred light. Spindle stPge and just after cleavage, 45-60 minutes after Same, infrared light.
visible
light.
fertilization,
visible
light.
Nut -1ei photographed by infrared light Visible
ARBACIA
399 Infrared
E. B. Harvey and G. I. Lavin
400 Visible
Fig. Fig. Fig. Fig.
5. 6. 7. 8.
ARBACIA
infrared
Plate.‘11 (Magnif. 280 x ). puncfulata, 4-ceil s&age, 1 l/z hrs. after fertilization, visible light, Same, infrared light. Blastulae, 3-4 hrs. after fertilization, visible light. Early and late blastulae, 3-8 hrs. after fertilization, infrared light.
Arbocin
Nuclei photographed by infrared light Visible
Infrared ARBACIA,
red
half-egg
CHAETOPTERUS,
Plate Figs. 9-11, magnif. 250 X; Figs. 12, Fig. 9. Arbacia punctulata, red half, Fig. 10. Same 2 hrs. after fertilization. Fig. 11. Arbacia pmcfulata, red half, Fig, 12. Chaefopferus pergamenfaceus, Fig. 13. Same, infrared light.
fertilized
unfertilized
III.
13, magnif. 300 x. 20 minutes after fertilization, 20 minutes-2 unfertilized,
visible
hrs. after fertilization, visible light.
light. infrared
light.
402
E. 13. Harvey and G. I. Lavin
The Chaetopterus egg, when viewed or photographed with ordinary light (Fig. 12) is quite opaque, and not much structure can be seen (3). In the infrared photographs the granular structure of the cytoplasm is seen, and the nuclear material of the unfertilized egg appears as a brilliant white area (Fig. 13). The general configuration of mitotic figures and nuclei is brought out by infrared because of its great penetrating power, especially through the red pigment granules. The detailed structure of the spindle and asters is not brought out by infrared because of its relatively poor resolving power. It is also owing to this that we do not see the fine granules in the cytoplasm, but only the coarser granules, as is evident in most of the photographs. TECHNIQUE
The eggs were photographed by the use of Kodak Infrared Sensitive plates. The developer was D 19. A tungsten microscope lamp was the light source. An image was arranged and focussed with a deep red light filter (Wratten 24 A) after which an infrared transmitting light filter (Wratten 88 A) was substituted for the photography. SUMMARY
Photographs, taken with infrared light, of all stages of dividing Arbacia punctulata eggs show the configuration of mitotic figures and nuclei as brilliant white areas against the dark granular cytoplasmic background. The photographs are very different from those taken with visible light. The nucleus and cytoplasm of the unfertilized Chaetopterus pergamentaceus egg which are quite opaque with visible light are quite striking with infrared light. REFERENCES 1. 2. 3. 4.
HARVEY, E. B., Biol. Bull., 62, 155 (1932). Biol. Bull., 71, 101 (1936). --Biol. Bull., 76, 384 (1939). Biol. Bull., 79, 166 (1940).