scholarly journals THE ULTRASTRUCTURE OF THE VITELLINE BODY IN THE OOCYTE OF THE SPIDER TEGENARIA PARIETINA

1957 ◽  
Vol 3 (6) ◽  
pp. 977-984 ◽  
Author(s):  
Jean André ◽  
Charles Rouiller
Keyword(s):  
Fine Structure ◽  
Metabolic Activity ◽  
Central Zone ◽  
Mature Oocyte ◽  
Gradual Transition ◽  
Retinal Rods ◽  
Regular Arrangement

The vitelline body in the mature oocyte of the spider Tegenaria parietina is composed of 4 different zones. 1. The central zone contains granular areas, vesicles, and a few lamellae. 2. The lamellar zone consists of numerous concentric lamellae. These sheets, 45 A in thickness, are stacked in groups. The fine structure and the regular arrangement recall those of myelin sheets, retinal rods, and chloroplasts. Between the stacks of lamellae, finely granular masses and various vesicles are to be found. 3. The "zone of transition" consists of a finely granular substance accumulated in abundant masses. This substance is composed of very closely packed granules about 50 to 60 A in diameter. Very often, near the lamellae, the granules show alignment giving a gradual transition from grains to lamellae. 4. The vesicular zone contains ergastoplasm, dense particles, mitochondria, and Golgi material. It is suggested that the peculiar ultrastructure of these cytoplasmic components may be related to an intense metabolic activity.

Fibroblasts During Hypertrophic Scar Formation and Resolution

1973 ◽  
Vol 31 ◽  
pp. 428-429
Author(s):  
C. W. Kischer
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Cell Proliferation ◽  
Fine Structure ◽  
Metabolic Activity ◽  
Hypertrophic Scar ◽  
Normal Skin ◽  
Ground Substance ◽  
Hypertrophic Scars ◽  
Scanning Electron

The morphology of the fibroblasts changes markedly as the healing period from burn wounds progresses, through development of the hypertrophic scar, to resolution of the scar by a self-limiting process of maturation or therapeutic resolution. In addition, hypertrophic scars contain an increased cell proliferation largely made up of fibroblasts. This tremendous population of fibroblasts seems congruous with the abundance of collagen and ground substance. The fine structure of these cells should reflect some aspects of the metabolic activity necessary for production of the scar, and might presage the stage of maturation.A comparison of the fine structure of the fibroblasts from normal skin, different scar types, and granulation tissue has been made by transmission (TEM) and scanning electron microscopy (SEM).

Electron Irradiation and Electron Tomography Studies of Glasses and Glass Nanocomposites

2008 ◽  
Vol 1107 ◽  
Author(s):  
G. Möbus ◽  
G. Yang ◽  
Z. Saghi ◽  
X. Xu ◽  
R.J. Hand ◽  
...  
Keyword(s):  
Fine Structure ◽  
Electron Tomography ◽  
Dark Field ◽  
Gradual Transition ◽  
Borosilicate Glasses ◽  
Redox Partner ◽  
Transmission Electron ◽  
Annular Dark Field ◽  
Microscopy Techniques ◽  
Electron Energy Loss

AbstractCharacterization of glasses and glass nanocomposites using modern transmission electron microscopy techniques is demonstrated. Techniques used include: (i) high-angle-annular dark field STEM for imaging of nanocomposites, (ii) electron tomography for 3D reconstruction and quantification of nanoparticle volume fractions, and (iii) fine structure electron energy loss spectroscopy for evaluation of boron coordination. Precipitation of CeO2nanoparticles in borosilicate glasses is examined as a function of glass composition and redox partner elements. A large increase in the solubility of Ce is found for compositions where Ce retains +IV valence in the glass. Irradiation experiments with electrons and λ-rays are summarized and the degree of damage is compared by using changes in the boron K-edge fine structure, which allows the gradual transition from BO4to BO3coordination to be followed.

scholarly journals Fine structure ot the protonema in the moss Ceratodon purpureus and its response to a cytokinin

2015 ◽  
Vol 47 (1–2) ◽  
pp. 143-152
Author(s):  
Krystyna Idzikowska ◽  
Alicja Szweykowska
Keyword(s):  
Fine Structure ◽  
Metabolic Activity ◽  
Structural Changes ◽  
Ceratodon Purpureus ◽  
Apical Cells ◽  
Cytokinin Treatment

Fine structure of the protonema is described, with a special attention to its differentiation depending on the position of cells in the protanemal filament, as well as in response to a cytokinin treatment. Complexes of micro-filaments with osmiophilic globules represented structures of particular interest. They appeared temporarily, almost exclusively in apical cells. The cytokinin treatment resulted in the apical cells in an increased number of cytokinetic figures and in structural changes indicating increased metabolic activity. In the intercalary cells, changes in response to the cytokinin were much smaller and mostly concerned an augmented development of the thylakoid system in chloroplasts. After a prolonged (5 days) treatment, degeneration symptoms developed in all cells, particularly in nuclei and chloroplasts, whereas the structure of mitochondria was relatively stable. The results are compared with the observations concerning the cytokinin-induced gametophore buds and with the data of biochemical and physiological investigations of the protonema.

The Life-Cycle of the Polychaete Nereis Virens

1972 ◽  
Vol 52 (3) ◽  
pp. 701-726 ◽  
Author(s):  
N. R. Bass ◽  
A. E. Brafield
Keyword(s):  
Fine Structure ◽  
Body Wall ◽  
Seminal Fluid ◽  
Mature Oocyte ◽  
The Body ◽  
Adult Males ◽  
Larval Life ◽  
Rate Of Development ◽  
Nereis Virens ◽  
Planktonic Phase

Adult males of Nereis virens (Sars) spawn while swarming in mid-water and show epitokous changes which include enlarged parapodia, natatory chaetae and histolysis of the body wall. Females spawn while in their burrows and do not show such changes. An artificial rise in temperature can induce premature spawning. Seminal fluid is ejected through pygidial pores, but no such pores occur in the female. Both lunar period and temperature rise seem to be involved in initiating spawning, which generally occurs in early May in the Thames populations. Gravid worms show a peculiar method of swimming in which the anterior region is held rigid. A pair of flagellar vanes and other features characterize the fine structure of the spermatozoon. The mature oocytes bear microvilli, and some express a jelly-like layer after fertilization which traps excess spermatozoa. Many unit-membraned vesicles, of uncertain function, occur in the periphery of the nucleus of the mature oocyte. At fertilization the acrosomal contents are discharged on to the surface of the oocyte. The structure and behaviour of the monotrochophore, trochophore and nectochaete larvae, and the details of the nature and rate of development of such structures as the parapodia, cirri, palps and jaws, differ in some ways from the known larval development of certain other nereids. A very brief planktonic phase occurs in larval life, and young worms migrate from the sublittoral to the littoral regions.

scholarly journals The Fine Structure of the Retina Studied with the Electron Microscope

1959 ◽  
Vol 6 (2) ◽  
pp. 225-230 ◽  
Author(s):  
Kiyoteru Tokuyasu ◽  
Eichi Yamada
Keyword(s):  
Plasma Membrane ◽  
Fine Structure ◽  
Electron Microscope ◽  
Outer Segment ◽  
Distal Region ◽  
Serial Sections ◽  
Tubular Structures ◽  
Detailed Structure ◽  
Subsequent Time ◽  
Retinal Rods

The morphogenesis of the outer segments of retinal rods was studied mainly in the kitten before the opening of the eye, and the probable sequence of the morphogenetic stages is deduced. Since the development of retinal rods is not synchronous, the deductions were based on observations of many single and serial sections. One centriole extends ciliary tubules of about 0.5 µ long, in the growing primitive cilium. Beyond this length, each ciliary tubule becomes a row of small vesicles (called "ciliary vesicles" in this paper), which penetrate into the distal region of the cilium. Where the ciliary vesicles establish contact with the plasma membrane of the distal region of the cilium, more or less deep infoldings of the plasma membrane are observed. In the distal region can be seen rows of tubular or vesicular structures. A few of these membranous structures are continuous with the bottoms of the infoldings. At the following stage, the infoldings disappear and the ciliary vesicles lose contact with the distal plasma membrane. Nonetheless, the formation of the tubular structures continues in the distal region of the primitive outer segment. The tubular structures appear to be transformed into the primitive rod sacs by sidewise enlargement. At a subsequent time, presumably, these primitive rod sacs flatten and are rearranged into a position perpendicular to the long axis of the outer segment. The detailed structure of the basal body of the connecting cilium was also studied by means of serial sections.

scholarly journals The Fine Structure of the Retina. V. Abnormal Retinal Rods and their Morphogenesis

1960 ◽  
Vol 7 (1) ◽  
pp. 187-190 ◽  
Author(s):  
Kiyoteru Tokuyasu ◽  
Eichi Yamada
Keyword(s):  
Fine Structure ◽  
Retinal Rods

scholarly journals Fine structure of kinetin-treated protonema and kinetin-induced gametophore buds in Funaria hygrometrica

2015 ◽  
Vol 40 (4) ◽  
pp. 549-555 ◽  
Author(s):  
F. Młodzianowski ◽  
A. Szweykowska
Keyword(s):  
Fine Structure ◽  
Metabolic Activity ◽  
The Other ◽  
Funaria Hygrometrica ◽  
Other Hand ◽  
Bud Induction ◽  
Development And Differentiation ◽  
High Metabolic Activity

Besides occasional hypertrophy of grana and disintegration of stroma thylakoids occurring in some chloroplasts, no significant changes were found in ultrastructure of typical protonema cells treated for six days with kinetin. On the other hand, the fine structure of cells in kinetin--induced gametophore buds differed much from that of the protonema cells and showed characteristics of cells of with high metabolic activity and high division rates. The results indicate that cytokinins enhance development and differentiation in the protonema by activating only some of its cells, whereas the others remain unchanged or show symptoms of destruction and ageing. This is supported by the fact that in the presence of chloramphenicol, which prevents bud induction, kinetin acts synergistically with the inhibitor in producing degeneration and destruction of chloroplasts.

Fine Structure of Platelet Interaction with a New Microcrystalline Collagen Preparation

1974 ◽  
Vol 32 ◽  
pp. 58-59
Author(s):  
W. H. Zucker ◽  
R. G. Mason
Keyword(s):  
Fine Structure ◽  
Platelet Aggregation ◽  
Hydrochloric Acid ◽  
Whole Blood ◽  
Platelet Adhesion ◽  
Hemostatic Agent ◽  
Native Collagen ◽  
Fibrillar Morphology ◽  
Clinical Interest ◽  
New Form

Platelet adhesion initiates platelet aggregation and is an important component of the hemostatic process. Since the development of a new form of collagen as a topical hemostatic agent is of both basic and clinical interest, an ultrastructural and hematologic study of the interaction of platelets with the microcrystalline collagen preparation was undertaken.In this study, whole blood anticoagulated with EDTA was used in order to inhibit aggregation and permit study of platelet adhesion to collagen as an isolated event. The microcrystalline collagen was prepared from bovine dermal corium; milling was with sharp blades. The preparation consists of partial hydrochloric acid amine collagen salts and retains much of the fibrillar morphology of native collagen.

Pituitary Follicular Cells: Their Origin, Possible Function and Fate

1974 ◽  
Vol 32 ◽  
pp. 34-35
Author(s):  
E. Horvath ◽  
K. Kovacs ◽  
G. Penz ◽  
C. Ezrin
Keyword(s):  
Fine Structure ◽  
Secretory Granules ◽  
Follicular Cells ◽  
Human Pituitary ◽  
Rat Pituitary ◽  
Pituitary Glands ◽  
Junctional Complexes

Follicular structures, in the rat pituitary, composed of cells joined by junctional complexes and possessing few organelles and few, if any, secretory granules, were first described by Farquhar in 1957. Cells of the same description have since been observed in several species including man. The importance of these cells, however, remains obscure. While studying human pituitary glands, we have observed wide variations in the fine structure of follicular cells which may lead to a better understanding of their morphogenesis and significance.

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