摘要:

Karyotypes of ten species of Brazilian rodents, collected in the State of Sao Paulo are presented:Akodon (Thaptomys) nigrita nigrita(2n= 52);Zygodontomys lasiurus(2n= 34);Thomasomys (Delomys) dorsalis collinus(2n= 82);Oxymycterus sp1.andOxymycterus sp2.(2n= 54);Calomys sp.(2n= 66);Clyomys laticeps laticeps(2n= 34);Euryzygomatomys guiara(2n= 46);Proechimys iheringi iheringi(2n= 62, 64) andEchimys sp.(2n= 90).

ISSN:0008-7114    

DOI:10.1080/00087114.1975.10796617

出版商:Taylor & Francis    

年代:1975

数据来源: Taylor

摘要:

Pachytene chromosomes ofSolanum nodiflorumJacq. (n= 12) a diploid form ofSolanum nigrumcomplex was studied. An idiogram was constructed showing chromosome lengths, lengths of chromatic and achromatic segments and arm ratio. The twelve chromosomes were readily distinguished on these criteria and described. Chromosome twelve has the nucleolus organizer in the short arm. The idiogram was compared with that of the Indian diploidS. nigrumL.

ISSN:0008-7114    

DOI:10.1080/00087114.1975.10796618

出版商:Taylor & Francis    

年代:1975

数据来源: Taylor

摘要:

Electron microscopy of glutaraldehyde and osmium tetroxide fixed ovaries reveals the nucellus cells as differentiated ones featuring large vacuoles, weakly developed RER, a relatively low hyaloplasm density, a relatively smaller size of the nucleolus and predominance of the fibrillar complex in them. Lipid bodies have been observed in the dilated sections of the space between the two membranes of the nuclear envelope or in close association with it. An explanation of this peculiarity is being sought by proceeding from analogous observations conducted by other authors.

ISSN:0008-7114    

DOI:10.1080/00087114.1975.10796619

出版商:Taylor & Francis    

年代:1975

数据来源: Taylor

摘要:

In primary cultures ofPleurodeleslung cells, the dependency of mitotic development on RNA synthesis was studied by means of several drugs, which have in common the inhibition of RNA synthesis (Actinomycin D, 3'Deoxyadenosine, Ethidium bromide, Acridine orange and Proflavine hemi-sulfate).

ISSN:0008-7114    

DOI:10.1080/00087114.1975.10796620

出版商:Taylor & Francis    

年代:1975

数据来源: Taylor

摘要:

The nuclear Feulgen-DNA content of presynthetic (G1) and post-synthetic (G2) selfed plasmodial nuclei of the Panamanian 2–4 (A7) isolate ofDidymium iridiswas measured by quantitative microspectrophotmetry. These values were then compared with values obtained from DNA studies of swarm cells bearing the mating alleles A2and A7, and Plasmodia produced from a cross between those isolates. The mean G1and G2values for the selfed Plasmodia were 0.148 and 0.277 respectively. Swarm cell of Honduran and Panamanian isolates which bear the mating alleles A2and A7were found to have mean DNA values of 0.292 and 0.283. The nuclear DNA content of a Plasmodium resulting from a cross between these isolates was 0.606. This value is equivalent to class 4C (replicated diploid). The G1selfed Plasmodia are, therefore, in class C. Based on these observations we conclude that selfed Plasmodia are produced without prior nuclear fusion, and are therefore haploid.

ISSN:0008-7114    

DOI:10.1080/00087114.1975.10796621

出版商:Taylor & Francis    

年代:1975

数据来源: Taylor

摘要:

The salivary gland cells ofTelmatoscopus albipunctatushave six polytene chromosomes variously connected and without any common chromocentre.

ISSN:0008-7114    

DOI:10.1080/00087114.1975.10796622

出版商:Taylor & Francis    

年代:1975

数据来源: Taylor

摘要:

Chromosomally the African Pigmy-Mice (Mus minutoides/musculoides)constitute a polymorphic system of Robertsonian type: 2n= 18–34, F.N. 36. The Leggadas of four populations originating from the Ivory Coast and the Central African Republic were studied: we report here the particular geographic distribution of the different karyotypes observed (the 2nvalues diminish in the West-East direction) and their frequencies. From this study we emphasize the hypothesis that speciation proceeds through successive steps which we can summarize in the following way: the first one is represented by the «initial polymorphism» of WALLACE (1959), the second one corresponds to a stage of chromosomal polymorphism and the last one is characterized by the establishment of a new species with a single diploid formula.

ISSN:0008-7114    

DOI:10.1080/00087114.1975.10796623

出版商:Taylor & Francis    

年代:1975

数据来源: Taylor

摘要:

Both numerical and structural chromosome abnormalities were found in carcinomatous effusions. Large dispersion of the chromosome numbers around the mode, small percentage of modal cells, and karyotype instability, were characteristics of the malignant cells. In every tumor, however, the variations were made around a basic pattern (stemline karyotype), consistent with a clonal origin for all cells of the tumor. Both ordinary polyploidy and endoreduplication represented mechanisms responsible for the cell gigantism found in tumors. The absence of chromosomal abnormalities in benign effusions makes the cytogenetic analysis of sediments a valuable tool for the differential diagnosis of malignancy in cavitary effusions.

ISSN:0008-7114    

DOI:10.1080/00087114.1975.10796624

出版商:Taylor & Francis    

年代:1975

数据来源: Taylor

摘要:

A spontaneously occurring hexaploid plant (2n= 6x=48) was found among white-flowered tetraploid plants ofMedicago sativa.

ISSN:0008-7114    

DOI:10.1080/00087114.1975.10796625

出版商:Taylor & Francis    

年代:1975

数据来源: Taylor

摘要:

Karyology ofNotoplana igiliensisGalleni was studied: karyogram and idiogram of the species are here reported.

ISSN:0008-7114    

DOI:10.1080/00087114.1975.10796626

出版商:Taylor & Francis    

年代:1975

数据来源: Taylor