Showing papers in "Journal of Ultrastructure Research in 1969"

TL;DR: A low-viscosity embedding medium based on ERL-4206 is recommended for use in electron microscopy and has a long pot life of several days and infiltrates readily because of its low viscosity.

TL;DR: A new staining method for ultrathin sections is proposed, which gives preferential contrast to certain cell structures known to contain RNA, whereas deoxyribonucleoproteins have lost most or all of the stain.

TL;DR: In the interphase nucleus, the distribution and fine structure of various components known to contain or should carry RNP have been investigated on ultrathin sections by means of a new preferential staining method and the use of various enzymatic and chemical extraction procedures.

TL;DR: Previous reports of the existence of two distinct cell types in the taste buds of rabbit foliate papillae must now be modified to include a third type, consisting of “typical” chemical synapses, with presynaptic densities against which the vesicles, particularly the synaptic vesicle, are crowded.

TL;DR: Barium permanganate is shown to be a useful fixative for preservation of the prespore cells and the significance of the three major functions of the Prespore vacuole in secretion, spore coat formation, and plasma membrane formation is discussed.

TL;DR: Rat megacaryocytes in the thrombocytogenic stage were studied in fetal liver and adult bone marrow to study the formation of cytoplasmic extensions protruding between neighbouring parenchymal cells or into sinusoids between sinusoidal lining cells.

TL;DR: Staining of nuclear proteins, presumably histones, in the meitoic chromosomes of the prophase nuclei of lily microsporocytes suggest that the lateral element of the synaptinemal complex may well contain a histone which may be synthesized in the early part of prophase.

TL;DR: The morphology of the testes and the development of sperm cells in the sea urchins Arbacia punctulata and Strongylocentrotus purpuratus have been investigated with techniques of light and electron microscopy.

TL;DR: It is likely hat the lead-positive material of the centers differs from that of the associated fibrillar nucleolonema because of slight differences in resistance of the material ofThe two nucleolar zones to pepsin and ribonuclease digestion.

TL;DR: A morphological study of the retina of worker honey bees as representatives of the closed-rhabdom type eye has been performed with the electron microscope as mentioned in this paper, where the effect of dark adaptation and the functional significance of these findings are discussed.

TL;DR: It is suggested that the blockage of mitosis usually associated with the initiation of cytodifferentiation can be correlated with the formation of cilia and maybe mediated by the transformation of the mitotic centrioles into ciliary basal bodies.

TL;DR: Planarian neoblasts were studied during the course of regeneration by electron microscopy and showed polysomal aggregations of ribosomes, prominent supernumerary nucleoli, endoplasmic reticulum forming at the nuclear membrane, and a curious kind of dense lump in close proximity to thenuclear membrane on the cytoplasmic side.

TL;DR: In this article, the authors studied the chick skin in order to obtain information about the differentiation products of epidermal cells and sequential events which lead to the formation of the horny layer.

TL;DR: In this article, the spermatozoon of Chloeon dipteron (Ephemeroptera) is examined and the three most important features are that the acrosome is very brief; the mitochondrial derivative is represented by a long mitochondrion with transverse cristae and by a crystalline mass enveloped in a separated membrane; and the axial filament of the tail lacks the two principal central units and the central sheath, and is therefore, of the 9 + 9 + 0 pattern.

TL;DR: It was concluded that the transverse bands consist of several, separate, parallel bands which, with their intervening spaces, trace a continuous helical path from the extracellular spaces at the nodes of Ranvier to the periaxonal spaces.

TL;DR: The origin of the melanosome in human melanoma in vitro was reinvestigated using an established cell line and it was found that most premelanosomes are contained in and develop within a tubular smooth endoplasmic reticulum, which is connected with the Golgi apparatus during melanogenesis.

TL;DR: During catagen, the cellular component of the connective tissue sheath consisting exclusively of macrophages, which form a tightly packed layer around the hair follicle, actively engulf and degrade the two layers of collagen fibers immediately surrounding the follicle.

TL;DR: By means of the ruthenium red method, acid mucopolysaccharides (AMP's) have been demonstrated in close association with synovial collagen using hyaluronidase and papain to indicate that these structures most probably consisted of chondroitin sulfate and hyaluronic acid-protein complexes.

TL;DR: During adaptation of rats to cold, the cellular morphology of their brown adipose tissue changes markedly, and mitochondrial cristae are remodeled first into a more irregular pattern composed of semicircles and loops, and subsequently, the cristAE become straight and also more numerous.

TL;DR: The formation of cellular cementum was studied by electron microscopy at the advancing edge of developing roots of molars of 25-day-old rats and it was found that the basement lamina about Hertwig's epithelial root sheath first becomes discontinuous on the dental sac side.

TL;DR: Measurements of crushing strength for spines of three species of sea urchin demonstrate that the strength to weight ratio of these spines is equivalent to or greater than that of mollusc skeletons and most calcareous rocks.

TL;DR: A “coated” vesicle type has been found in neurosecretory axon terminals of the crustacean sinus gland, in addition to the previously described dense-cored granules and “synaptic”vesicles, suggesting origin of one or both vesicles types from the plasma membrane by micropinocytosis.

TL;DR: Small oocytes in adult Rana pipiens contain a number of cytoplasmic bodies which resemble nucleoli in size, shape, and staining reactions, but these nucleolus-like bodies are, however, more finely granular than nucleoli.

TL;DR: The fine structure of spermatid differentiation in the sculpin Oligocottus maculosus is described and nuclear pores show a consistent and highly specific arrangement which may have functional significance.

TL;DR: The nonregularly oriented filamentous structures of different muscle cells were investigated in hearts of the rhesus monkey and rabbit, and some connective tissue-embedded muscle cells of some force-producing myocardial fibers showed some of the morphological characteristics usually associated with the myotendinous junction.

TL;DR: A relationship between “membrane-like” profiles, fibrous material, and inclusion bodies was shown which is believed to reveal a possible process by which protein subunits are assembled into a growing crystal.

TL;DR: The elementary cellulose fibril is a universal structural unit of natural cellulose, similar to that found in cotton, ramie, and jute, studied before.

TL;DR: Serial section studies strongly suggest that each pair of thick fibers corresponds to a pair of second-order fibers lying in the center of an optical cartridge in the lamina, which may provide anatomical support for a sequence detector of stimuli moving between space points projected on the medulla.

TL;DR: The fine structures of the gametocytes of various malarial parasites were investigated and compared and a possible origin of thegametocytes from asexual merozoites is also discussed.

TL;DR: In this article, a tricomplex fixation technique was used to visualize the surface-active component of a saturated phospholipid component of surfactant within lung tissue.