Showing papers in "Developmental Biology in 1969"

TL;DR: Mammary gland rudiments of 12- to 14-day mouse embryos developed typically in organ culture, forming a nipple with a nipple sheath, a ramifying duct system, and adipose tissue, while rudiments taken from 16-day embryos failed to develop under the same culture conditions.

TL;DR: In this paper, the role of cyclic-AMP in normal development of an acrasin (cyclicAMP) and the sensitivity to acrasins in the cellular slime mold Dictyostelium discoideum was examined.

TL;DR: Small fragments of mesoderm and endoderm have been transplanted from stage 5 donor embryos labeled with thymidine- 3 H to corresponding sites in nonlabeled hosts, and these fragments heal in and participate in the normal development of the recipient embryo.

TL;DR: Serum chromatograms demonstrate that most of the variable labeling of the serum is the function of a single serum component, designated SLPP, which appears to transform into the two proteins of the crystalline yolk platelet, phosvitin and lipovitellin, and hence represents the precursor molecule for crystallineYolk.

TL;DR: It is suggested that maturation does not require concomitant DNA-dependent RNA synthesis, but that protein synthesis is obligatory for all stages of maturation.

TL;DR: In this paper, the X-ray-induced somatic crossing-over was used to demonstrate that cell lineage data can yield important information regarding various developmental problems in Drosophila melanogaster.

TL;DR: Developmental changes in the composition of isolated chromatins and their ability to support RNA synthesis have been studied in trout testes undergoing spermatogenesis artificially induced by gonadotropin injections.

TL;DR: Stats indicate that there is a significant increase in protein and copper concentrations of the hemolymph during oocyte maturation, and it is probable that lipovitellin is synthesized external to the ovary and transferred to the oocytes during vitellogenesis.

TL;DR: The ectomesoderm of the area vasculosa of the chick embryo of the definitive primitive streak stage was cultured with or without endoderm present on the opposite side of a Millipore filter to study the development of blood islands and the nature of tissue interactions.

TL;DR: The results support previous reports that thyroxine and low oxygen tension may play a physiological role in chondrogenesis in vivo.

TL;DR: BUdR is incorporated into DNA in place of thymine, its effect on differentiation can be competitively prevented by simultaneous inclusion in the medium of TdR or compounds readily convertible to TDR, and it has no detectable effect on postmitotic cells (muscle fibers).

TL;DR: During the time that eggs are developing, the fat body from female Leucophaea maderae synthesizes a protein with characteristics similar to a subunit of the major yolk protein during density gradient centrifugation.

TL;DR: The asymmetry in cell numbers may be the expression of a primary difference between the developmental potencies of right and left heart primordia through which the laterality of the heart loop formation is determined.

TL;DR: The hypothesis that subcellular events accompanying germination of the zoospore of Blastocladiella emersonii are the result of local membrane alterations requiring rearrangements of preexisting structures is proposed.

TL;DR: Protein synthesis, thus, is accelerated at fertilization by the translation of additional mRNA molecules, and translation level control of protein synthesis cannot be a general change in activity of some component in the cellular synthetic machinery such as ribosomes, but must specifically control the activity of a defined population of mRNA molecules.

TL;DR: The decrease in synthetic capacity of regenerating tissue can be reproduced in in vitro organ culture and it is suggested that the nerve may exert a direct control over the synthesis of DNA, RNA, and protein in regenerating tissues.

TL;DR: In the unfertilized egg of the sea urchin Paracentrotus lividus it is possible to detect a small number of polyribosomes active in protein synthesis, which starts to increase rapidly very soon after fertilization and the polyribsomes become progressively heavier during the first cell cycle.

TL;DR: A morphological study of the skin of developing stages of Fundulus places the present “plywood” theory of basement lamella structure and development in doubt and supports a new “scindulene (shingle)’ theory.

TL;DR: The working hypothesis presented is that normal embryonic induction depends upon an endogenous source of ions, and that there is an intracellular release of ions within the embryo during late gastrulation.

TL;DR: This article showed that BUdR at low levels (10−7 M) can completely but reversibly inhibit the expression of differentiation by chondrocytes grown as single cell derived clones in a modification of Ham's medium F10.

TL;DR: It is concluded that d-looping and asymmetry of the heart tube must result from mechanisms other than differential lateral mitotic activity, and based on evidence for an earlier onset of differentiation on the right side, a hypothesis of heart asymmetry is suggested.

TL;DR: Results indicate that the γ-crystallins, previously implicated in bovine and regenerating newt lens fiber differentiation, are also indicative of lens Fiber differentiation in the normal, developing lens of the anuran amphibian, R. pipiens .

TL;DR: The juvenile hormone was shown to maintain the threshold of epidermal cells to the bristle-forming substance, a threshold which falls during normal cellular metamorphosis, and the results supported the adoption of the Wigglesworth model for bristle development as a working hypothesis.

TL;DR: Heterogeneity in zoospore populations with respect to time of germination can be predictably varied by controlling the density of growth cultures from which the zoospores are derived.

TL;DR: A study has been made of the onset of RNA and protein synthesis in encysted gastrulae of the brine shrimp, Artemia salina, during their transition from an ametabolic (cryptobiotic) state to active life and renewed embryonic development.

TL;DR: It is suggested that extracellular matrix is the active agent in the suppression of myogenesis and an attempt was made to duplicate the suppressing activity of multilayer cultures by using ion exchange resins as substrates for myogenic cells.

TL;DR: The pulse-chase experiments show that the methylated part of 40 S RNA is converted to 28 S and 18 S RNA, the 18 SRNA appearing as such very early, and the 28 S RNA appearing after some intermediate processing steps involving 30–32 S species.

TL;DR: The pattern of RNA synthesis in hybrids is seen to be abnormal several hours before developmental arrest, and may be causally connected with it.

TL;DR: It has been found that the embryonic shoot apex completes its development at ca.