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1.
Summary Genome sizes of the planariansD. lugubris (2n=8),D. polychroa (2n=8) andD. benazzii (2n=16) were evaluated on metaphase plates by measuring both the Feulgen-DNA contents and the karyotype lengths. In the three species, genome sizes are significantly different; this finding rules out the possibility of a karyotype evolution through simple chromosome rearrangements betweenD. lugubris andD. polychroa. A different Feulgen-DNA content per unit length of karyotype in the three species studied was also found, which suggests that DNA could be differently packed along metaphase chromosomes.  相似文献   

2.
Summary The metaphase chromosomes ofChironomus th. thummi contain approximately 17% more pericentric C-band heterochromatin than the chromosomes ofChironomus th. piger with 11% heterochromatin. InCh. th. thummi, the proportion of heterochromatin appeared to be much larger in metaphase chromosomes than in polytene chromosomes. This discrepancy is interpreted as being due to the specific chromosome organization and not as the result of an underreplication of heterochromatin during polytenization.  相似文献   

3.
Summary The author shows that the conception of an incomplete sex-linkage in mammals must be discarded on cytological grounds. There is either (general case) pre-reduction of theX andY chromosomes at the first metaphase, or post-reduction (Apodemus) but never facultative post-or pre-reduction.During the growth period, from the Zygoteny to the Diacinesis, the occurrence ofc -o is made highly improbable, owing to the heteropycnotic state of the sexchromosomes, and has never been observed with accuracy. The revision of the literature shows that such an hypothesis is not tenable.The obligatory post-reduction byApodemus can be interpreted in the concept of anticipation centromérique.In a very few cases, formations like chiasmas occur as linking theX andY chromosomes at the first metaphase. It is possible that these exceptional configurations might be explained by a translocation of the sex-chromosomes on a pair of autosomes.From a more general standpoint, it would be desirable that geneticians should have more confidence in the results of pure cytologists rather than in the work of cytogeneticians who wish to find an explanation for every genetical hypothesis.

Institut de Zoologie et d'Anatomie comparée.  相似文献   

4.
Summary After treatment ofHordeum vulgare, Secale cereale, Triticum aestivum andAvena sativa with Lindan-containing seed dressings, the somatic chromosomes in the root tip mitoses were analyzed. Most of the chromosome sets in the root tip cells have been polyploidized. Using pure Lindan (-hexachlorocyclohexane), it could be shown that this insecticide is responsible for the induction of polyploidy.

Für gewissenhafte Mithilfe bei den cytologischen Untersuchungen danken wir FrauG. Westermeier, Frl.E. Kunzmann und HerrnO. L. Koller.  相似文献   

5.
Summary Ultrastructural changes in spleen and liver in a case ofMorbus Gaucher andNiemann-Pick are discussed.The results are: (1) The Ultrastructure shows a distinct differentiation between the two diseases. (2) It seems that storage begins in mitochondria. (3) In the case ofMorbus Niemann-Pick, all Mitochondria of storage cells show an abnormal ultrastructure (diminuation in size, increased osmiophilia, disorder in the arrangement of cristae and membranes).

Die Arbeit erscheint ausführlich an anderer Stelle.  相似文献   

6.
The origin of the brown frogs with 2n=24 chromosomes   总被引:1,自引:0,他引:1  
Late replication and C-banding analyses of somatic metaphase chromosomes were attempted on three species of brown frogs with 2n=26 chromosomes (Rana japonica, R. tsushimensis andR. temporaria), and three with 2n=24 chromosomes (R. ornativentris, R. dybowskii andR. chensinensis), which are distributed in the Palearctic region. The late replication banding patterns were highly conserved in these species. Four chromosome inversions were demonstrated inR. ornativentris, two inR. dybowskii and two inR. tsushimensis. From a detailed comparison of late replication and C-banding patterns between the 2n=26 and the 2n=24 species, it was found that an end-to-end fusion of two small chromosomes (nos 11 and 13) in an ancestral 2n=26 species may have produced the medium-sized no. 6 chromosome of the 2n=24 species.  相似文献   

7.
Summary In meristematic cells ofAllium cepa, vinblastine induces accumulation of prophase and metaphase stages, chromosome contraction and C-metaphases, appearance of bridges at anaphase, multipolar divisions at anaphase and telophase, micronucleus formation at telophase, and faint staining reaction and degeneration of nuclei or chromosomes at all stages.The 2nd article of this series will be published in Mem. Fac. Integrated Arts and Sci., Hiroshima Univ., Ser. IV, vol.3.  相似文献   

8.
Summary Polytene chromosomes have been found in a cell complex associated with the humerus imaginal disc ofDrosophila melanogaster.

Wir danken unserem Lehrer, Herrn Prof. Dr. E.Hadorn, herzlich für die Anregung zu dieser Arbeit und die kritische Durchsicht des Manuskripts. Zu Dank verpflichtet sind wir auch Fräulein M.Staub, die uns bei der Herstellung der mikroskopischen Präparate geholfen hat.  相似文献   

9.
The karyotype of a lungless salamander,Onychodactylus fischeri, from Korea was analyzed and compared with that of the Japanese congeneric species,O. japonicus. In both species the diploid karyotype consists of78 chromosomes, including 6 pairs of large chromosomes, 6 pairs of medium-sized ones, and the remaining 27 pairs of microchromosomes. The chromosome number ofO. fischeri, 2n=78, is, like that ofO. japonicus, the largest so far reported in the order Urodela. C-banding showed that constitutive heterochromatin inO. fischeri was mainly in the centromeric regions and near the secondary constrictions of the large chromosomes. AgNO3-bands were located in the secondary constrictions associated with C-band heterochromatin.  相似文献   

10.
Summary Dry and presoaked seeds ofNigella damascena were treated with aqueous extracts of the mushroomPaxillus involutus. At the first mitosis after the onset of germination, metaphase chromosomes showed damage independent of the origin of the mushrooms. The damaging substance(s) is (are) thermostable. Except a few achromatic gaps, all the lesions observed are of the chromosome type, i.e. are induced at the pre-synthetic G1 stage.  相似文献   

11.
Summary Butazolidin in a concentration of 10 mg% does not inhibitin vitro the activity of rat liver monoamine- and cytochromoxydase.

Die Untersuchungen wurden im Pharmakologischen Institut der Universität des Saarlandes, Homburg, durchgeführt.  相似文献   

12.
Résumé Dans les leucoyctes en culture de 7 TenrecsCentetes ecaudatus (4 mâles et 3 femelles) provenant de la République Malgache, l'auteur a compté 38 chromosomes et constaté que les sexes ont un caryocyte distinct. C'est la première étude faite sur les chromosomes d'un représentant de la famille des Tenrecidae (Insectivores).

Skin fibroplast cells were cultured fromCentetes ecaudatus (Animal No. 2). These cells gave a count of 38 chromosomes. Using the same techniques as above, whole blood cultures of the related tenrec,Hemicentetes semispinosus G. Cuvier, were counted. Preliminary studies indicate 38 chromosomes for this speices.  相似文献   

13.
Conclusion Somatic heterochromatization of the opossum,D. virginiana, was studied from prophase and tritiated thymidine-labeled metaphase chromosome preparations. In both sexes of this mammal, a number of prophase autosomes and the sex chromosomes were observed displaying deeply stained condensed areas. These chromosomal areas were interpreted as evidence for heterochromatization. The extent of heterochromatization in the opossum was found much greater in certain autosomes than either theX orY chromosome alone. This assertion that some opossum autosomes possess more heterochromatin than the sex chromosomes was supported by data collected on the terminal labeling patterns of the chromosomes. Metaphase autoradiographs prepared from cultured leucocytes of the animals unequivocally suggested that certain opossum autosomes completed replication later than the sex chromosomes. If one assumes that there is heterochromatin in the autosomes, as the evidence suggests, then it merely becomes a question as to what block of heterochromatin replicates last — a phenomenon that is probably size dependent.
Résumé L'héterochromatisation somatique de l'opossum (Didelphys virginiana) a été étudiée sur des préparations de chromosomes aux stades de la prophase et de la métaphase, la thymidine ayant été utilisée comme marqueur. Dans les 2 sexes de ce mammifère de nombreux autosomes et les chromosomes sexuels montrent, à la prophase, des plages denses fortement colorées. Ces plages chromosomiales ont été interprétées comme un signe évident d'héterochromatisation. L'héterochromatisation est beaucoup plus accentuée dans certains autosomes que dans les chromosomesX ouY. Les autoradiographies de stades métaphasiques dans des préparations effectuées de leucocytes en cultures suggèrent d'une façon non équivoque que certains autosomes de l'opossum achèvent leur réplication plus tardivement que les chromosomes sexuels. Si l'on assume que l'héterochromatine est présente dans les autosomes, comme le démontrent nos observations, il semble évident que l'héterochromatine autosomale a un rôle significatif dans le développement.


Supported in part by Baylor University College of Medicine General Research Grant (No. P-13) and grants from the James Picker Foundation and the Texas Heart Association. The auther wishes to thank Dr.W. Hill for his help at the vivarium and MissMarion Gay and MissShirley Powell for technical assistance. The editorial assistance of MissMarilyn Morningstar is also appreciated.  相似文献   

14.
Summary From the mycelium ofFusarium orthoceras App. et Wr. var.enniatinum n. v. we have isolated in crystalline form a new antibiotic substance called Enniatin. The chemical and biological characteristics of this substance are described. Enniatin is especially activein vitro against several mycobacteria.

Ausgeführt mit einem Beitrag aus den Arbeitsbeschaffungskrediten des Eidg. Militärdepartements.  相似文献   

15.
Summary Tightly packed elementary fibrils with a diameter of 20 Å are demonstrated in human metaphase chromosomes in situ.
Demonstration von Elementarfibrillen in menschlichen Metaphasechromosomen in situ

Für die Mithilfe bei der Präparation danke ich FrauM. Brun del Re; für die Aufnahmen mit dem Philips EM 300 bin ich HerrnJ. di Lullo vom Veternärmedizinischen Institut der Universität Bern zu Dank verpflichtet.  相似文献   

16.
Summary Hellebrigenin was converted to Scilliglaucosidin-19-ol and 3-Epi-Scilliglaucosidin-19-ol. This proves the correctness of the assumption ofStoll et al. 3 that the aldehydic group of Scilliglaucosidin is in position C-10.Comparison of a reduction product of Nabogenin, a substance isolated earlier from the bulbs ofBowiea volubilis Harvey, with Scilliglaucosidin-19-ol and 3-Epi-Scilliglaucosidin-19-ol showed its identity with the first named compound. This proves that the so called Nabogenin was a mixture consisting mainly of Scilliglaucosidin.

8. Mitteilung über die Glykoside vonBowiea vocubilis Harvey und 162. Mitteilung über Glykoside und Aglykone.

7. Mitt.:A. Katz, Helv. chim. Acta38, 1565 (1955).

161. Mitt.:H. Kündig-Hegedüs undO. Schindler, Helv. chim. Acta39, 904 (1956).  相似文献   

17.
Summary 2% aqueous solution of urethan causes after 6–10 hours' action on root types ofVicia faba andAllium cepa a shortening of chromosomes, it stops also the metaphase and lowers the rate of mitosis. Probably there is a connection between the lipophile groups, the reduction in surface tension, and the diminution of chromosomes. Dioxan with similar physical properties has the same effect.  相似文献   

18.
Zusammenfassung Mit Hilfe vonNocardia restrictus wurde aus Tomatidin in 60% Ausbeute 1,4-Tomatadien-3-on erhalten.

Taken in part from the forthcoming doctorate dissertation ofH. Soi.  相似文献   

19.
Résumé Le rat KangourouDipodomys panamintinus a 4 sous-espèces. Le représentatif karyotype de 4 des sousespèces a 17 métacentriques et 14 chromosomes acrocentriques.Dipodomys panamintinus caudatus, géographiquement isolé des autres, a 16 métacentriques et 15 chromosomes acrocentriques. Le nombre fondamental est 96 pour les espèces.

We wish to acknowledge the kind assistance of the following people in preparation of this paper: Mr.Dave Dunaway, Resident Naturalist, U.S. Forest Service; Mrs.Tilly Chamness, Coordinator, Natural Resource Management, Naval Weapon Center, China Lake.  相似文献   

20.
Résumé En utilisant le chromosome T6 pour des expériences de transplantations dans la souris, nous avons trouvé des cellules contenant 41 chromosomes et le trisomique pour le chromosome T6.

This work was supported by The Spastics Society, A.A.M. was in receipt of a grant from the Instituto de Alta Cultura, Portugal. Mr.L. Kelberman processed the photograph.  相似文献   

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