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Disaccharide, wie beispielsweise Maltose, Glucose. Fruc-tose, Galaktose, Mannose; audi Zuckeralkohole, wie Sorbit und Mannit, zeigen diesen Effekt. Es bilden sich wasserlösliche gemischte Komplexe aus Dextran, Sac-charid und Cu". Nadi diesen Befunden ist anzunehmen, daß diejenigen in der Literatur angegebenen Dextran-werte zu niedrig sind, bei denen eine der genannten Sub-stanzen anwesend war, und außerdem, daß insbesondere die höhermolekularen Anteile des sehr polymolekularen Dextrans in erheblichem Ausmaß in der Leber gespei-chert werden.

Diese an Dextran entwickelte Indizierungsmethode mit 35S läßt sich auf andere makromolekulare Substanzen, insbesondere Polysaccharide nebst Derivaten und Pro-teine übertragen. Vor der üblichen Indizierung mit 14C hat sie den Vorteil der wesentlich niedrigeren Kosten, der einfachen und schnellen Durchführbarkeit und großen Empfindlichkeit infolge der sehr geringen Verdünnung durch inaktiven Schwefel.

Herrn Dr. W. H e r t l e i n , Pharmakol. Institut der Universität Freiburg i. Br., danken wir sehr herzlich für seine Mithilfe bei den Tierversuchen. Unser Dank gilt ferner der D e u t s c h e n F o r s c h u n g s g e m e i n s c h a f t , dem F o n d s d e r C h e m i e sowie der Firma K n o l l A.G., Ludwigshafen, für die Unter-stützung der Arbeit.

Maximum Mitosis and Water Content In Regenerating Rat Liver

By F. G. Z a k i *, Ph.D. Max-Planck-Institut für Biochemie, Abtlg. Virusforschung,

Tübingen * (Z. Naturforschg. 9 b. 239 241 T1954]; eingeg. am 19. Jan. 1954)

Previous reports on the regeneration of rat liver tissue after partial hepatectomy showed considerable fluctuation in the maximum of mitotic activity which was found to occur after 24, 30, 36, 48 and 72 hours from the opera-tion J—5 a. This difference in response of mitotic activity may be due to many factors, among which is age, sex, body weight, diet, or may also be due to different strains of the same species 5 h.

It was aimed at first to isolate mitotic nuclei from homogenates of regenerating liver. Because of the variations in results of different authors, it seemed of interest, therefore, to confirm the period of maximum mitosis. In relation to this work, the change in water content of the liver during regeneration was studied.

M e t h o d s : Partial hepatectomy adopted by B r u e s ,

* Present Address: Faculty of Science, University of Cairo, Giza, Egypt.

1 A. M. B r u e s and B. B. M a r b l e , J. exp. Medi-cine 65, 15 [1937].

2 R. E. S t o w e l 1, Arch. Path. 46, 164 [1948]. 3 J. M. P r i c e and A. K. L a i r d , Cancer Res. 10.

650 [1950], 4 R. D. H a r k n e s s , J. Physiol. 116, 373 [1952], 5'» H. O. Y o k o y a m a , M . E . W i l s o n , K . K . T s o u b i

and R. E. S to w e l l , Cancer Res. 13, 80 [1953]. sb H.O. Y o k o y a m a , M . E . W i l s o n , K . K . T s o u b i

and R. E. S t o w e l l , Ibid. 13, 86 [1953], e A. M. B r u e s , D. R. D r u r y and M. C. B r u e s ,

Arch. Path. 22, 652 [1936].

D r u r y and B r u e s 6 was applied to 2 and 6 months old rats of strain B. D. I (D r u c k r e y), and weighing 100—280 gms. The lobes excised were the left lateral and median whidi were found to make up 68.9 ± 2.3 (deviation is calculated as ± 2 oM per cent of the total liver weight). This value is in good agreement with that found by other workers 6> 7> 8. There was a loss of 2.6 ± 1 per cent in the body weight due to the removal of these lobes. Animals were kept at room temperature in individual cages and were fed ad libitum.

Observations were made on the regenerating liver by killing the animals at intervals of 24, 30, 36, 48, 72 and 96 hours after partial hepatectomy. For such interval, a group of 4—6 rats of the same litter was used. Homogenates of normal and operated livers were prepared according to the recent technique adopted by H o g e b o o m et al.9.

Changes in the water content of normal and operated liver were calculated by drying small slices to constant weight in an oven at 100° C. Samples of the liver tissue removed at partial hepatectomy were used as the control for those taken from the regenerating liver of the same animal.

For histological studies, random portions of the original and regenerating livers were fixed in Z e n c k e r , B o u i n - D o u b o s c q , and A l l e n B o u i n fluids, embedded in paraffin and sectioned at 5 u. These sections were stained with haematoxylin-eosin and with F e u I g e n nuclear stain. The method for counts of mitosis quoted by H a r k n e s s 4 and Y o k o y a m a et al.5 a was applied, and only the parenchymal cells were counted*. These counts included the late prophase, metaphase and telophase. F e u I g e n nuclear stain was found the best for nuclear counts from microscopic sections.

Observations

1. M a x i m u m M i t o s i s . Table 1 as well as figure 1 summarise the mitotic activity of the regenerating liver at different intervals. The periportal distribution of the dividing cells at the early stages (24 hours) goes parallel with those reported by H a r k n e s s 4 . However, this distribution is no more longer regular afterwards, i.e., mitosis has been found everywhere in the different lobes.

After 24 hours, the percentage of parenchymal cells in mitotic division was low and on average was

j per cent. Later on, mitosis increased and by

the second day, however, it reached its highest activity. In 2 months old rats, on average, mitosis counted

+ 2.0 5 4 18 P e r c e n t a ^ e r ^ hours. Age is an important

* The Variance was calculated according to the equation given by H. v. S e h e Hing 16.

l e H. von Sc h e l l i n g , Forschungsinst. Chemotherap. Arb. staatl. Inst. exp. Therap. Frankfurt a. M. 37, 28 [1939].

7 M. W. C r a n d a 11 and D. L. D r a b k i n . T. biol. Chemistry 166. 653 [1946].

s M. E . L o m b a r d o , L. R. C e r c e d o and D. V. N. R e d d y , J. biol. Chemistry 202. 97 [1953].

9 G. H. H o g e b o o m , W. C. S c h n e i d e r and M. Jo S t r e i b i c h , Cancer Res. 13, 617 [1953].

** This averege was taken from other determinations (4.0; 4.9; 4.7; 4.5; 4.4; 5.3; 3.4; 6.0; 4.0; 5.4; 5.4; 5.2; 5.3; 4.2 and 5.0). The variance is calculated for 2.5 T according to the ..student" (T) distribution equation.

*** This mean was determined from other data (6.4; 6.8; 5.2; 5.5; 5.5; 6.0; 4.8; 5.4; 5 4; 5.1; 4.5 and 4.3).

Table 1. Ratio of excised lobes to original body weight and to original liver weight, loss in body weight post opera-tion, changes in water content during regeneration, and mitosis in liver cells after certain periods of partial hep-atectomy. All data were taken from rats 2 months old, while those preceded by * were taken from rats 6 months old.

Sex Partial hepat.

[hours]

Original body

Liver removed to body weight

[%]

Excised liver Loss in

body weight

Water content Mitosis Sex

Partial hepat.

[hours]

weight

gms

Liver removed to body weight

[%] lobes [%]

Loss in body

weight normal liver

operated liver

increase of water

[°/o] average [%] average

cf cf cf 9 .

24 24 24 24

117 109 132 120

2.3 3.2 2.9 2.8

60.5 84.0 76.0 73.5

8.5 13.7 9.3

10.5

69.0 71.5 70.9 70.4

69.0 71.8 71.6 70.8

0.0 0.3 0.7 0.4

0.4 + 0.6 1.2 1.6 1.5 1.4

! 4 + 0.5 * 0,3

* 9 24 190 2.5 65.7 5.5 — — — 0.8

9 cf d O

36 36 36 36

142 105 139 129

2.6 2.4 2.5 2.5

68.6 63.1 65.7 65.8

9.1 2.8 7.2 6.4

70.0 71.2 71.4 70.9

73.4 77.2 75.4 75.3

3.4 6.0 4.0 4.4

**4.8 + 0.8 3.4 4.2 4.3 4.0

4 0 - 2 - 1 4.U ± l A

*cf 36 258 2.3 60.5 8.9 — — — 2.4

cf 9 Q

• CT

48 48 48 48

121 100 93

105

3.1 2.5 2.5 2.7

81.5 65.7 65.7 70.9

14.5 9.0 5.5 9.6

68.0 70.5 70.2 69.6

71.1 74.7 72.9 72.9

3.1 4.1 2.7 3.3

3.3 + 1.0

5.5 6.0 4.8 5.4

5 4 2<1 b A 1.8

* 9 48 234 2.5 65.7 6.5 — — 3.5

9 9 9 cf

60 60 60 60

143 142 101 129

2.7 2.8 2.2 2.6

70.9 73.5 57.5 67.4

9.8 9.9

12.0 10.5

70.4 69.0 69.8 69.7

72.9 72.0 73.5 72.8

2.5 3.0 3.7 3.1

3.1 ± 0.9 3.6 3.0 2.9 3.2

* * * 3.2 ±

* 9 60 220 2.8 73.5 10.0 — — — 2.0

cf cf d1

cf

72 72 72 72

118 107 115 113

2.3 2.8 2.7 2.6

60.5 73.5 70.9 67.8

9.3 9.3 8.4 9.6

70.0 70.7 70.0 70.2

72.1 73.5 71.2 72.3

2.1 2.8 1.2 2.1

2.1 + 1.5 3.0 2.2 2.8 2.7

2 7 4- L 8 ± 1.1

*d 72 172 2.7 73.6 10.3 — — — 2.0

cf 9 9 9

96 96 96 96

133 101 119 118

2.4 2.7 2.5 2.5

63.1 73.6 65.2 65.2

14.2 10.0 10.0 11.4

70.2 71.8 70.6 70.9

72.4 75.2 72.9 73.5

2.2 3.4 2.4 2.6

2.6 + 1.2 1.4 1.6 1.8 1.6

, R , 0.6 L 6 x 0.3

* 9 96 260 2.6 65.7 8.2 — — — 1.0

factor affecting the rate of mitosis. 6 months old rats showed lower rate of mitosis.

In such case, the liver showed a maximum mitotic activity not exceeding 3.5% on the second day (Table 1).

2. W a t e r C o n t e n t . Some workers noted that during the first 24 hours there was a considerable decrease in the water content of the regenerating liver10 '11 . On the other hand, others detected an increase in the

10 G. M. H i g g i n s and R. H. A n d e r s o n , Arch. Path. Lab. Med. 12, 186 [1931].

11 C. M. S z e g o and S. R o b e r t s , J. biol. Che-mistry 178, 827 [1949],

water content of such livers 12>13. Harkness found gradual increase from 71/100 gm of liver to 73.9/100 gm at 70 hours.

In the present experiments there was a significant rise in the water content up till 36 hours, where it reaches maximum, then there is a tendency to drop gradually. However, at 72 and 96 hours the water content was still higher than normal (Fig. 2).

This observation goes parallel with the mitotic 12 F . N . G u r d , H . M . V a r s and S . R a v d i n , Amer.].

Physiol. 152, 11 [1948]. 13 R. D. H a r k n e s s , J. Phvsiol. 117, 267 [1950].

US 60 hours

Fig. 1. Percentage of rat liver cells in mitosis at intervals during regeneration.

melt wurde, konnte ich die kleine, nur aus wenigen Kam-mern bestehende Foraminifere Rotaliella heterocaryotica n. g. n. sp. isolieren. Da sieb diese Art leicht in Boveri-schalen züchten läßt, war es möglich, den ganzen Ent-wicklungszyklus aufzuklären.

Bei der Gamogonie führt der Gamont (Abb. 1 a), wel-cher nur einen Kern besitzt, mehrere Kernteilungen durch, so daß etwa 12—24 Gametenkerne gebildet wer-den. Die Gameten sind amöboid und kopulieren inner-halb des gleichen Gamonten miteinander (Autogamie). Gelegentlieh legen sich aber auch zwei Gamonten an-einander (Gamontogamie), wobei wahrscheinlich ein wechselseitiger Austausch von Gameten stattfindet. In jedem Gamonten entstehen etwa 6—12 Zygoten, die sich zu den Agamonten entwickeln.

Abb. 1. Rotaliella heterocaryotica n.g.n.sp. b Agamont (halbschematiseh).

a Gamont.

Uß 60 hours

Fig. 2. Increase in water content of liver during regeneration.

activity with a lapse of 12 hours difference, viz., the cells contained the highest amount of water before being engaged in mitosis by 12 hours. The same observation has been reported by A s t w o o d 1 4 working on the uterus of young rats, and by B r i c k 1 5 working on the action of follicular hormone on the uterine wall of castrated mice. In the latter case the interval difference between the high content of water and the maximal mitotic activity of such cells was 15 hours.

The author would like to express his deep gratitude to Prof. F r i e d r i c h - F r e k s a for suggesting this work, as well as for his keen interest and valuable advice he was always ready to give during this research.

Kerndualismus bei einer Foraminifere Von K a r l G. G r e l l

Max-Planck-Institut für Biologie, Abt. Hartmann, Tübingen (Z. Naturforschg. 9 b, 241 [1954]; eingeg. am 1. März 1954)

Aus Algenmaterial, welches in der Nähe des meeres-biologischen Institutes in Rovinjo (Jugoslawien) gesam-

14 E. B. As t w o o d , Endocrinology 23 [1938], 15 K. B r i c k , Dissert., Tübingen, Germany, 1950.

Wie bei Patellina corrugata ( M y e r s , 1935) beginnt die Agamogonie bereits vor dem Ausschlüpfen der Aga-monten. Durch zwei metagame Teilungen werden in jedem Agamonten vier Kerne gebildet, die zunächst alle gleich aussehen. Von diesen Kernen schwillt dann aber einer an und bildet einen Nucleolus aus, während die drei anderen kondensiert bleiben. Beim Ausschlüpfen be-sitzt daher jeder Agamont drei kleine Kerne („Mikro-nuclei"), welche in der Anfangskammer liegen, und einen großen Kern („Makronucleus"), der im Verlauf des Zell-wachstums in eine der jüngeren Kammern hereinrückt und offenbar physiologisch aktiv ist (Abb. lb ) . An der Meiose, die wie bei Patellina corrugata (Le C a l v e z . 1950) intermediär verläuft und in zwei Teilungssehritten besteht, beteiligen sich nur die drei kleinen Kerne, wäh-rend der große pyknotisch wird und schließlich zugrunde geht. Die kleinen Kerne kann man daher als generativ, den großen als somatisch bezeidinen. Jeder Agamont liefert 12 Agameten, welche wieder zu den Gamonten heranwachsen. Gamonten und Agamonten sind äußerlich nicht voneinander zu unterscheiden. Ihre Anfangskammer ist gleichgroß.

Bei der Foraminifere Rotaliella heterocaryotica n.g.n.sp. ist somit zum erstenmal im Protistenreich eine Differen-zierung in Keimbahn und Sorna verwirklicht, die sich ausschließlich in einem Kerndimorphismus äußert und an die Verhältnisse der Ciliaten erinnert. Eine ausführ-liche Arbeit über die Entwicklung erscheint im „Archiv für Protistenkunde".