C-band differentiation between the chromosomes of two subspecies of the chironomid midge Chironomus thummi

The metaphase chromosomes of Chironomus th. thummi contain approximately 17% more pericentric C-band heterochromatin than the chromosomes of Chironomus th. piger with 11% heterochromatin. In Ch. 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.     

Simple chromosome banding technique for farm animal investigations]

For routine cytogenetic investigations, a simple banding technique on chromosomes is described. Used on different cell material, a visible banding appearance is produced which makes the typing of chromosomes precise and fast. On 2 examples of cattle and rabbit chromosomes, the identification of a centric fusion and a trisomic is shown.     

C-band differentiation between the chromosomes of two subspecies of the chironomid midgeChironomus thummi

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.     

Larvale und imaginale Mitteldarmchromosomen vonDrosophila repleta

Summary In certain tissues ofD. repleta-flies, it is possible to observe the interphase chromosomes that are either of larval origin or that occur in imaginal tissues. The imaginal interphase chromosomes from the midgut are similar to the small larval midgut chromosomes in the early phases of their development.     

Die Genomsonderung in den Mitosen der Rattenleber

Summary Model squashes with gelatine cubes containing 8 files like the chromosomes ofBellevalia romana (2n=8) showed the chromosomes only in groupings that correspond to the original position of metaphase chromosomes. The metaphase chromosomes in root tip cells ofBellevalia romana are arranged at random; there is neither somatic pairing nor genome segregation (= grouping of metaphase chromosomes into two complete chromosome sets). In contradiction to these results, the chromosomes in the regenerating liver cells (2n=42) show a certain precentage of grouping into complete genomes. It is concluded that in rat liver cells a mechanism exists which, starting with the genome segregation, may produce a change in chromosome number. Thus these same euploid or aneuploid chromosome numbers can be explained which are really observed in normal and treated rat liver. 4 possibilities of such mechanism are discussed.

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Nach einem Vortrag, gehalten anlässlich des IV. Symposium histologicum internationale Lausanne (Suisse), 5.–8. September 1961.     

Trends of karyological evolution in Pelobatoid frogs

Summary The Pelobatids have a basal karyotype of 26 chromosomes, with 6 pairs of large and 7 of small chromosomes (6+7). From this karyotype, shown byLeptobrachium, Pelobates andScaphiopus, those ofMegophrys andSpea (5+8) may be derived, as well as that ofL. pelodytoides, with only 24 chromosomes.Pelodytes has 24 chromosomes and a karyotype 7+5 differing from that of typical Pelobatids under several respects.Research supported by a contribution from the Italian C. N. R.     

The mitotic chromosomes of the lampreyMordacia mordax (agnatha: Petromyzonidae)

Résumé L'étude des chromosomes somatiques de la lamproie de l'hémisphère sud,Mordacia mordax (Richardson), montre que l'équipement chromosomique diploïde de cette espèce est composé de 76 chromosomes très petits. La plupart des chromosomes sont métacentrique ou bien submétacentrique. Ces chromosomes sont différents en nombre de ceux décrits pour les lamproies de l'hémisphère nord.     

Variation in chromosome number in the sheep headflyHydrotaea irritans (Fallen) (Diptera: Muscidae)

Summary Variation in the number of chromosomes was found in sheep headflies, ranging from 12 to 15 chromosomes. Of these, five pairs were common among all individuals. Among 9 larvae no males were identified.     

Age-G staining, a rapid technique for producing combined silver staining and Giemsa banding in mammalian chromosomes

A combination of the silver staining method with a Giemsa banding technique is described for mammalian chromosomes. This double staining simultaneously shows silver-stained NORs and a G-band pattern, and thus allows a rapid identification of the NOR-bearing chromosomes.     

Spontaneous robertsonian fusion leading to karyotype variation in the house mouse — First report from Asia

Summary The occurrence of spontaneous Robertsonian fusion leading to 2n=39 chromosomes (NF=40) in the house mouse (Mus musculus domesticus) has been reported for the first time from Asia. 3 phenotypically normal female mice collected from 2 distantly located populations of India (Tripura and Calcutta) show centric fusion in somatic chromosomes between pairs 2 and 16, and 8 and 14 respectively. C-banding analysis revealed that the (sub) metacentric has been originated by fusion between the broken/eroded centromeres of 2 telocentric chromosomes.     

Ag-G staining,a rapid technique for producing combined silver staining and Giemsa banding in mammalian chromosomes

Summary A combination of the silver staining method with a Giemsa banding technique is described for mammalian chromosomes. This double staining simultaneously shows silver-stained NORs and a G-band pattern, and thus allows a rapid identification of the NOR-bearing chromosomes.     

High levels of transition metals in dinoflagellate chromosomes

X-ray microanalysis of fixed, sectioned chromosomes of the dinoflagellates Glenodinium foliaceum, Prorocentrum micans and Amphidinium carterae has revealed high levels of iron, nickel, copper and zinc. We report high levels of these transition metals in association with chromosomes in intact eukaryote cells.     

Possible target of Abelson virus phosphokinase in cell transformation

By fusing interphase cells to cells undergoing mitosis, the interphase chromosomes can be visualized. When analyzed in this way, chromosomes of normal mouse cells show characteristic undercondensed centromeric regions. We have found that the centromeric regions of chromosomes from Abelson virus-transformed cells are fully condensed. Abelson virus transforms mouse cells by introducing into them a virally encoded phosphokinase that is expressed constitutively. Thus, we propose that the condensation of centromeric chromatin is a result of overphosphorylation by the Abelson virus phosphokinase, and that the centromeric region is the relevant target of overphosphorylation in transformed cell growth.     

A simple one-step procedure for staining the nucleolus organizer regions

Summary A simple silver staining technique for routine use is described by which the nucleolus organizer regions of mammalian chromosomes, including those of mouse chromosomes, are stained selectively.Acknowledgment. We would like to thank Prof. Dr K. Sperling for critical and helpful discussion.     

Differential giemsa staining of the holokinetic chromosomes of the two-spotted spider mite,Tetranychus urticae Koch (Acari,Tetranychidae)

Summary The chromosomes of the spider miteTetranychus urticae can be stained differentially with Giemsa-staining methods for G-bands. C-band patterns representing constitutive heterochromatin could not be detected. Their absence may be related to the holokinetic condition of the chromosomes.     

The mitotic chromosomes of the lamprey,Petromyzon marinus L.

Résumé L'étude des chromosomes somatiques de la lamproie,Petromyzon marinus L. a montré que l'équipment chromosomique diploïde de cette espèce est composé de 168 chromosomes très petits, dont queleues-uns des plus grands sont métacentriques. Le chiffre semble représenter le plus grand nombre de chromosomes trouvé dans une espèce de Vertébré. On a comparé les chromosomes de P.marinus avec ceux des autres espèces de lamproies.

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Holder of a Science Research Council Fellowship.     

Supernumerary chromosomes in Drosophila nasuta albomicana

Supernumerary chromosomes have been detected in the karyotype of D.n.albomicana. Their number varies from one to three. They are the smallest elements in the karyotype. Karyotypes of D.n.albomicana with and without supernumerary chromosomes have been presented.     

Heterozygote Zentrenfusion bei einer weissen Laborratte

Summary A centric fusion of 2 acrocentric chromosomes in a female laboratory rat is described. The phenotype was normal. The new chromosome is submetacentric. Other animals of the same group showed such new chromosomes only sporadically. No information is available of chromosome mosaic, fertility or genetics of this animal.     

Additional chromosome duplication in female meiotic prophase ofSipyloidea sipylus Westwood (Insecta,Phasmida), and its absence in male meiosis

Summary In the parthenogenetic stick insectSipyloidea sipylus, an additional chromosome duplication takes place in the primary oocytes immediately after pachytene. After duplication, the chromosomes again appear in a pachytene configuration, and oogenesis proceeds with twice the somatic number of chromosomes. Additional duplication does not occur during prophase of primary spermatocytes.     

Chromosome complement of tenrecs,Centetes ecaudatus (Order Insectivora,Class Mammalia)

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).

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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.