摘要:

Light and electron microscopy of the white body ofTodarodes sagittatusand of the bone marrow ofRattus rattushave revealed certain similarities between the cells of the leucocyte series in a Cephalopod and those of the granulocyte series in a Mammal. These similatrities are also due to active protein synthesis in their cytoplasm. The series studied can be assigned to “the cells of activesynthesis having an irreversible course”.

ISSN:0373-4137    

DOI:10.1080/11250008009438678

出版商:Taylor & Francis Group    

年代:1980

数据来源: Taylor

摘要:

The administration of partially purified homologous follicular stimulating hormone to adult females ofRana esculentahypophysectomized during the growth phase of the ovaries is followed by an increase of estrogens and progesterone in the blood. The luteinizing hormone seems to act by increasing only the progesterone level. These effects are eliminated by ovariectomy. In autumn and winter, hypophysectomy seems to affect only slightly the low levels of circulating hormones, probably because in that period the gonads are less sensitive to hormones from the pituitary.

ISSN:0373-4137    

DOI:10.1080/11250008009438679

出版商:Taylor & Francis Group    

年代:1980

数据来源: Taylor

摘要:

The presence of actin and myosin revealed by indirect immunofluorescence, in the synaptonemal complex of various vertebrates seems to be related to chromosome pairing during meiosis, to contraction of the protein scaffolding of the paired chromosomes, and to packing of the DNA-histone loops during meiotic prophase.

ISSN:0373-4137    

DOI:10.1080/11250008009438680

出版商:Taylor & Francis Group    

年代:1980

数据来源: Taylor

摘要:

Progress in embryology and developmental biology over the last two centuries is sketched. Today's research is discussed as an introduction to the Symposium.

ISSN:0373-4137    

DOI:10.1080/11250008009438681

出版商:Taylor & Francis Group    

年代:1980

数据来源: Taylor

摘要:

The presumptive somite mesoderm of the primitive streak stage does not form somites if it is totally isolated from other tissues. Hence it has been proposed that the somites form by embryonic induction, but since no single tissue has been found to be essential, this concept has become less credible. Instead, the segmentation process appears to take place in two major steps: (1) as the node regresses, an early programming establishes the number and bilaterality of the somites, occurring as a wave of change passing from the anterior to the posterior end of the body; (2) after an interval of about 20 h, a second wave passes down the body and converts the programmed cells into somites. This theory is supported by morphological and experimental evidence.

ISSN:0373-4137    

DOI:10.1080/11250008009438682

出版商:Taylor & Francis Group    

年代:1980

数据来源: Taylor

摘要:

An electron microscopic analysis of replication intermediates in chromosomal DNA from several systems has been made. In all of them, besides entirely double stranded molecules, only molecules with clustered small “eyes” and partially or entirely single stranded molecules were observed. Early cleavage embryos of D.melanogasteralone showed the presence also of molecules with long replication “eyes”. These patterns strongly support a unifying interpretation we recently proposed for chromosomal DNA replication in eukaryotes.

ISSN:0373-4137    

DOI:10.1080/11250008009438683

出版商:Taylor & Francis Group    

年代:1980

数据来源: Taylor

摘要:

Results from the treatment of amphibian(Xenopus laevis)and fish(Salmo gairdneri)embryos with several polluting substances (LAS, ammonia, urea and melamine mixtures, melamine and cadmium) are reported.

ISSN:0373-4137    

DOI:10.1080/11250008009438684

出版商:Taylor & Francis Group    

年代:1980

数据来源: Taylor

摘要:

Recent data on the structure and stability of mRNA in various cell lines are examined for the presence in the mRNA molecule of the polyadenylate segment and its possible role in maintaining high translational efficiency. Data on the synthesis and storage of maternal mRNAs in amphibian oocytes and their utilization during early embryonic development are also examined.

ISSN:0373-4137    

DOI:10.1080/11250008009438685

出版商:Taylor & Francis Group    

年代:1980

数据来源: Taylor

摘要:

Present knowledge of the regenerative capacity of the anuran eye has been synthesized.

ISSN:0373-4137    

DOI:10.1080/11250008009438686

出版商:Taylor & Francis Group    

年代:1980

数据来源: Taylor

摘要:

Numerous experimental observations have stressed the significant effects of pressure and flow patterns in cardiovascular morphogenesis. The role of bilaminar streams in septation of the heart and the importance of hemodynamic factors in the evolution of the aortic arch system have been shown experimentally in the chick embryo. Changes in the hemodynamics of the circulatory system result in cardiovascular malformations.

ISSN:0373-4137    

DOI:10.1080/11250008009438687

出版商:Taylor & Francis Group    

年代:1980

数据来源: Taylor