scholarly journals Further Observations on the Fine Structure of Chrysochromulina chiton with Special Reference to the Pyrenoid

1966 ◽  
Vol 1 (2) ◽  
pp. 187-192 ◽  
Author(s):  
IRENE MANTON
Keyword(s):  
Endoplasmic Reticulum ◽  
Fine Structure ◽  
Special Reference ◽  
Glutaraldehyde Fixation ◽  
Transparent Material ◽  
Chloroplast Membranes ◽  
Outer Pair ◽  
Translucent Material ◽  
Push Out ◽  
Local Accumulation

Developments associated with the surface of the projecting pyrenoids of Chrysochromulina chiton have been traced in outline after glutaraldehyde fixation. In the simplest condition the pyrenoidal core is separated from the cytoplasm by two superposed pairs of membranes, the outer pair being continuous with a layer of endoplasmic reticulum spread over the surface of the subtending chloroplast. Various stages in the formation and removal of an additional membrane-bounded cap of translucent material are illustrated and interpreted in terms of local accumulation of a temporary storage metabolite in the path of translocation of materials from the chloroplast into the cell. A cap is thought to begin as a blister involving the innermost pair of membranes which become pushed apart as the transparent material accumulates between them. A bulge, involving the outer of the two separated membranes plus contents of the blister, could then push out between meshes in the overlying endoplasmic reticulum before spreading laterally. This process is not light-dependent. It is suggested that enzymes localized between the chloroplast membranes in this region are acting on a soluble translocation metabolite. At mitosis, and shortly after, the capping material may be absent.

Quick-freeze, deep-etch rotary replication of Trypanosoma cruzi and Herpetomonas megaseliae

1984 ◽  
Vol 69 (1) ◽  
pp. 167-178
Author(s):  
T. Souto-Padron ◽  
W. de Souza ◽  
J.E. Heuser
Keyword(s):  
Endoplasmic Reticulum ◽  
Plasma Membrane ◽  
Fine Structure ◽  
Trypanosoma Cruzi ◽  
Basal Body ◽  
Glutaraldehyde Fixation ◽  
Triton X

The fine structure of epimastigotes of Trypanosoma cruzi and promastigotes of Herpetomonas megaseliae was analysed in replicas of quick-frozen, freeze-fractured, deeply etched and rotary-replicated cells. Using control cells and cells treated with Triton X-100 before glutaraldehyde fixation, images were obtained that showed connections of the sub-pellicular microtubules with each other, with the plasma membrane, and with the endoplasmic reticulum. Images were also obtained that showed the DNA network in the kinetoplast. Filamentous structures were found to connect the kinetoplast to the basal body, and to connect the main basal body to the accessory one. In addition, deep-etch images of detergent-extracted flagella display dynein arm substructure and the filamentous architecture of the paraxial structures.

scholarly journals STUDIES ON FINE STRUCTURE AND CYTOCHEMICAL PROPERTIES OF ERYTHROPHORES IN SWORDTAIL, XIPHOPHORUS HELLERI, WITH SPECIAL REFERENCE TO THEIR PIGMENT GRANULES (PTERINOSOMES)

1965 ◽  
Vol 27 (3) ◽  
pp. 493-504 ◽  
Author(s):  
Jiro Matsumoto
Keyword(s):  
Electron Microscopy ◽  
Endoplasmic Reticulum ◽  
Fine Structure ◽  
Special Reference ◽  
Water Soluble ◽  
Xiphophorus Helleri ◽  
Swordtail Fish ◽  
Pigment Granules ◽  
Pteridine Derivatives ◽  
Tubular Endoplasmic Reticulum

The fine structure and the composition of pteridine pigments of erythrophores in adults of the swordtail fish, Xiphophorus helleri, were studied by means of cytochemistry, paper chromatography, ionophoresis, centrifugal fractionation, and electron microscopy. It was found that water-soluble pigments of erythrophores consisted exclusively of pteridine derivatives including large amounts of drosopterin, isodrosopterin, neodrosopterin, and moderate amounts of sepiapterin. While these substances were responsible for red pigmentation, moderate quantities of colorless pteridines, biopterin, Rana-chrome 3, xanthopterin, isoxanthopterin, and others, were also detectable. The ultrastructure of the erythrophore is characterized by numerous pigment granules and a well developed tubular endoplasmic reticulum. The former consist of a three-layered limiting membrane and inner lamellae which appear to be whorl-like due to a concentric arrangement of parallel membranes. All of the mentioned pteridines are primarily contained in this organelle which is designated, accordingly, "pterinosome." The possible functions of erythrophores and pterinosomes are discussed in the light of their structure and pigmentary constitution.

Changes in the Fine Structure of the Desiccation-Tolerant Sedge Coleochloa setifera (Ridley) Gilly Under Water Stress

1979 ◽  
Vol 27 (5) ◽  
pp. 531 ◽  
Author(s):  
M Bartley ◽  
ND Hallam
Keyword(s):  
Electron Microscopy ◽  
Endoplasmic Reticulum ◽  
Protein Synthesis ◽  
Fine Structure ◽  
Water Stress ◽  
Rough Endoplasmic Reticulum ◽  
Structural Changes ◽  
Chloroplast Membranes ◽  
Fixation Techniques ◽  
Moderate Stress

Electron microscopy demonstrated gross changes to organelles during dehydration, particularly in chloroplasts which lose thylakoids. Plastoglobuli increase in size as internal chloroplast membranes develop into vesicles. An increase in polysomes and in rough endoplasmic reticulum after moderate stress suggested the possibility of increased protein synthesis at this time. The loss of chlorophyll while grana were still evident suggested an ordered destructuring of the chlorophyll. In dry tissue the nucleus remained intact, mitochondria contained few indistinct cristae and chloroplasts appeared as organelles containing vesicles and plastoglobuli. Both aqueous and anhydrous fixation techniques were used to follow h e structural changes on drying.

scholarly journals Fine structure of lipotubuloids (elaioplasts) in Ornithogalum umbellatum L. I.

2015 ◽  
Vol 40 (3) ◽  
pp. 451-465 ◽  
Author(s):  
M. Kwiatkowska
Keyword(s):  
Endoplasmic Reticulum ◽  
Fine Structure ◽  
Rotary Motion ◽  
Osmiophilic Granules

The bodies occurring in the ovary epidermis cells of <i>Ornithogalum umbellatum</i>, rich in lipids have been earlier described as elaioplasts. They consist of agglomerations of osmiophilic granules within the cytoplasm, caught in a network of, and interconnected by, a system of interesecting microtubules. These structures have been named lipotubuloids. They translocate in the cell by way of a progressive-rotary motion. Endoplasmic reticulum membranes, ribosomes and very scarse mitochondria and Golgi structures occur within the lipotubuloids.

Fine structure of prolactin pituitary adenoma with special reference to annulate lamellae

1979 ◽  
Vol 46 (1-2) ◽  
pp. 163-166 ◽  
Author(s):  
M. Scanarini ◽  
R. Giordano ◽  
S. Mingrino ◽  
N. Pennelli
Keyword(s):  
Fine Structure ◽  
Pituitary Adenoma ◽  
Special Reference ◽  
Annulate Lamellae

The fine structure of reproducing Toxoplasma gondii

Parasitology ◽  
1963 ◽  
Vol 53 (3-4) ◽  
pp. 643-649 ◽  
Author(s):  
Emeka G. Olisa
Keyword(s):  
Endoplasmic Reticulum ◽  
United Kingdom ◽  
Fine Structure ◽  
Toxoplasma Gondii ◽  
Binary Fission ◽  
The United Kingdom ◽  
Research Scholarship ◽  
Fixation Techniques ◽  
Different Shapes ◽  
Nigerian Government

1. Different shapes and forms found in Toxoplasma gondii are associated with reproduction and growth. The functions of the toxoneme and the conoid are discussed.2. A new structure, ‘lamella spiralis', is described in relation to the nucleus and the endoplasmic reticulum.3. T. gondii reproduces either by dividing into two (binary fission) or by multiple division (schizogony), and by a type of endogenous budding. In the latter case small portions pinched off from the nucleus are rounded up to form several small organisms named ‘morulae'.The author gratefully acknowledges the interest and valuable suggestions of Dr G. A. Gresham, M.D., who supervised this work; Dr J. M. Davis and Mr F. Allen, who were kind enough to read the manuscript critically, and Mr W. A. Mowlam for his technical help and advice on fixation techniques.This work was carried out during the tenure of a research scholarship awarded by the United Kingdom Department of Technical Co-operation and the Eastern Nigerian Government.

Observations on the Fine Structure of the Eyespot and Associated Organelles in the Dinoflagellate Glenodinium Foliaceum

1969 ◽  
Vol 5 (2) ◽  
pp. 479-493 ◽  
Author(s):  
J. D. DODGE ◽  
R. M. CRAWFORD
Keyword(s):  
Endoplasmic Reticulum ◽  
Fine Structure ◽  
Lamellar Body ◽  
Ventral Side ◽  
Close Packing ◽  
Hexagonal Close Packing ◽  
Osmiophilic Granules ◽  
Algal Groups ◽  
Posterior Direction ◽  
Microtubular System

The eyespot of the marine dinoflagellate Glenodinium foliaceum is a flattened orange structure, more or less trapezoid in shape with an anterior hook-like projection. It is situated on the ventral side of the organism in the vicinity of the flagellar bases at the anterior end of the sulcus. In the electron microscope the eyespot is seen to contain two layers of osmiophilic granules 80-200 nm in diameter which usually show hexagonal close-packing. The eyespot is surrounded by a triple-membraned envelope and is not connected to any other organelle. Adjacent to the eyespot is a distinctive organelle termed the ‘lamellar body’. This consists of a stack of up to 50 flattened vesicles or disks, each 16 nm thick and about 750 nm wide, the whole being orientated in an antero-posterior direction. The lamellae are continuous, at the ends of the stack, with rough endoplasmic reticulum and are joined together by occasional bridges at their edges. The bases of the two flagella lie just ventral to the lamellar body and from them roots arise which pass by the eyespot and join the subthecal microtubular system. The eyespot of Glenodinium is unique both in structure and the presence of the associated lamellar body. It differs from eyespots which have been described from other algal groups and also from the more complex ocellus found in certain dinoflagellates belonging to the order Warnowiaceae. The method by which the eyespot functions is discussed and it is suggested that unidirectional stimuli could be perceived by shading of the lamellar body.

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