Showing papers in "Differentiation in 1977"

TL;DR: Dfferentiation properties of a cell line, L84, which originated from a non-fusing clone isolated from the myogenic line L8, are described and show that L84 cells retain the programme for their differentiation into muscle fibres.

TL;DR: Investigation of the timing of histone synthesis and replacement by testis-specific basic nuclear protein (TSP) during spermatogenesis in the mouse suggested that repeated specific alterations in the protein complement of the nucleus are an integral part of sperMatogenic differentiation in the mice.

TL;DR: The results suggest that a decrease in [cAMP]i may be specific and obligatory for nuclear membrane dissolution during the first meiotic division and that a primary action of progesterone may be to increase free Ca2+ in the oocyte cytoplasm, which in turn may activate a phosphodiesterase and lower intracellular cyclic AMP levels.

TL;DR: Reciprocal intergeneric hybrid crosses were made between two species of centrarchids, the largemouth bass and the green sunfish, where the hybrid embryos derived from the reciprocal GSF ♀ × LMB ♂ cross were morphologically abnormal, and all died near the time of hatching.

TL;DR: The hypothesis is that a Ca surge in the early phase of fertilization is responsible for the inactivation of CSF in the oocytes, bringing about the resumption of meiosis, whereas Mg, which enhances CSF activity in vitro, serves to maintain the conditions necessary for metaphase arrest.

TL;DR: During gastrulation all the cells migrating through the primitive streak have the same appearance regardless of their eventual destination in the embryo, attributable to the type of movement made by cells during invagination.

TL;DR: Radioactive polypeptides co-migrating with LC3 were synthesized in significant amounts in a cell-free system directed by pre-fusion RNA and increased only moderately when RNA extracted after fusion was used.

TL;DR: Results favour the idea that membrane-bound calcium is released from the membrane as an initial step following hormone exposure, and seem to indicate a mode of action of the steroid at a membrane level with concomitant release of calcium normally bound to membrane phospholipids.

TL;DR: The results suggest that albumin does indeed play a role in the induction of the hamster sperm acrosome reaction rather than just in capacitation, and that the ligand content of albumin can influence its effectiveness in the induction of the acrosomes.

TL;DR: In the model discussed here the fatter postulate is favoured, suggesting that the differentiation process is guided by the continuous and sequential changes of the microenvironment of the cell.

TL;DR: Quantitative changes in the activities of twelve different enzymes have been investigated during early development in both the warmouth and the green sunfish, suggesting a minimal maternal contribution of enzyme activity to the developing zygote, combined with the initiation of synthesis of new enzyme molecules during the earliest embryonic stages.

TL;DR: It was found that although the proportion of the RNA polymerase enzyme forms changes from the 8-cell to the blastocyst stage of development, the types of newly synthesized nucleic acids at each of these stages were similar, and it was concluded that the synthesis of different classes of RNA by preimplantation mouse embryos is not simply controlled by changes in the levels of the multiple forms ofRNA polymerase.

TL;DR: No correlations can be found between the ganglioside pattern and the ability of cells to synthesize neurotransmitters and Morphological differentiation obtained by serum deprivation, dibutyryl cyclic AMP or bromodeoxyuridine does not restore a true neuronal pattern in this type of cell.

TL;DR: Evidence that chimeric drift may have an immunological basis is suggested after it was found that the parental composition of the peripheral white blood cells changed significantly during a two-month interval in 11/33 or 33% of the mice studied.

TL;DR: Cell numbers and amounts of DNA, RNA and protein in early chick blastoderms during the developmental period of 0–52 h of incubation are determined and the period when doubling time increases coincides with the folding and fusion of cell sheets, as well as with the establishment of defined organ primordia.

TL;DR: The observations suggest that the 'extra DNA body' observed in early oogenic stages of both species represents a dense aggregate of numerous short circular units of nucleolar chromatin, with morphological subcomponents identifiable in ultrathin sections.

TL;DR: These analyses indicate that there is stage-specific protein synthesis in the primary spermatocyte which is characterized by differential activation of the LDH-C locus and of the gene coding for cytochrome ct.

TL;DR: Keratohyalin granule-like aggregates and tangles of filaments similar to epidermal prekeratin fibrils have been observed in lactating cells of bovine mammary epithelium, demonstrating that keratinization can take place in functional secretory cells.

TL;DR: The results suggest that the differentiation of the choanocytes and the further morphogenesis of the aquiferous system depend on the repetitive divisions of the archaeocytes that normally occur around 90 h.

TL;DR: It appears likely that as the hormone appears, selection becomes involved in the proliferation of cells possessing receptors and this observation might not only be of phylogenetic interest, but could also be relevant in receptor maturation as manifested in ontogenetic membrane differentiation.

TL;DR: Sperm histones display great variability in contrast to the conservation of most classes of somatic histones, and Species within the class Amphibia therefore exhibit considerable diversification in their type of basic sperm proteins.

TL;DR: It is suggested that cytoplasmic inadequacies, rather than genome imbalance, are responsible for the reduced ability of the eggs stimulated with high doses of PMS to reach the blastocyst stage in vitro.

TL;DR: The decrease in the amount of bound HC in the nuclei of induced cells was accompanied by an increase in the level of HC receptors in the cytoplasm, which suggests that the reappearance of HC receptor in the cell cy toplasm may be due, at least in part, to de novo synthesis ofHC receptors.

TL;DR: It was found that the neural tissues induced by the same inducer of the notochord were not uniform but varied in type, and it was shown that the types of neural tissue differed according to different quantities of the surrounding mesenchyme.

TL;DR: It is suggested that cell differentiation is based on a continuous reprogramming of nuclear function, including the coding both for substances specific to the terminal differentiation and for the programming factors themselves.

TL;DR: It is suggested that the steroid enzyme activities present in the embryos are not solely derived from the oocytes but synthentized during early development.

TL;DR: It is shown that the interphase can be shortened for cell populations of low density by reducing the external cyclic AMP levels surrounding the amoebae, and it is suggested that low cell densities require a longer period of time to achieve the appropriate relationship between external cyclIC AMP and cell-bound phosphodiesterase and therefore have a longer interphase.

TL;DR: The results suggest that melanocytes of the Ww genotype, although capable of producting normally pigmented fur in Ww animals, fail to populate hair follicles when the competition with wwcc (albino) melanocytes that are wild type at the W locus.