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.

Temperature Effects on Formation and Fine Structure of Brassica napus Leaf Waxes

1976 ◽  
Vol 24 (3) ◽  
pp. 309 ◽  
Author(s):  
DJ Armstrong ◽  
MI Whitecross
Keyword(s):  
Electron Microscopy ◽  
Endoplasmic Reticulum ◽  
Fine Structure ◽  
Brassica Napus ◽  
Growth Temperature ◽  
Temperature Effects ◽  
Structural Changes ◽  
Leaf Waxes ◽  
Surface Waxes ◽  
Biochemical Level

Incorporation of 1-14C-palmitic acid, a precursor of leaf waxes, into leaf strips of Brassica napus was examined by thin section autoradiography and electron microscopy. Label was found to be associated with mitochrondria, Golgi vesicles and endoplasmic reticulum of epidermal cells, and also with the outer epidermal wall across which cuticular lipids are expected to migrate. Variations in growth temperatures produced structural changes in surface waxes as previously reported but no specific correlation could be found between changes in surface fine structure and variations in subcellular morphology. It is concluded that variations in wax fine structure, as influenced by growth temperature, resulted from effects at the biochemical level.

scholarly journals Ultrastructure of rhesus monkey renomedullary interstitial cells

1979 ◽  
Vol 13 (2) ◽  
pp. 75-80 ◽  
Author(s):  
David J. Lewis ◽  
David E. Prentice
Keyword(s):  
Electron Microscopy ◽  
Endoplasmic Reticulum ◽  
Fine Structure ◽  
Rhesus Monkey ◽  
Rough Endoplasmic Reticulum ◽  
Lipid Droplets ◽  
Stellate Cells ◽  
Interstitial Cells ◽  
Prominent Feature

Summary The fine structure of rhesus monkey renomedullary interstitial cells was studied by electron microscopy. These stellate cells contained variable numbers of lipid droplets, moderate numbers of mitochondria, moderate amounts of rough endoplasmic reticulum, and prominent Golgi zones. In rare instances, apparent release of lipid droplets into the interstitium was observed. The most prominent feature of the interstitial cells was large nuclear pseudoinclusions which were observed in a high proportion of the animals examined.

scholarly journals Fine structure of the integument of Argas (Persicargas) persicus (Oken) (Ixodoidea: Argasidae)

2005 ◽  
Vol 16 (4) ◽  
Author(s):  
Ashraf Montasser ◽  
Amr Amin
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Endoplasmic Reticulum ◽  
Fine Structure ◽  
Rough Endoplasmic Reticulum ◽  
Epidermal Cells ◽  
Argas Persicus ◽  
Dermal Glands ◽  
Transmission Electron ◽  
Surface Pores

The integument of Argas persicus was investigated using light, scanning and transmission electron microscopy. The study revealed that two layers, viz. an outer epicuticle and an inner procuticle, form the cuticle. The epicuticle includes wax, cuticulin and protein epicuticular layers. The wax layer carries numerous crater-like deposits, oval or circular discs and numerous infoldings. The procuticle contains an exo-, endo- and a subcuticle.Underlining the cuticle, flattened epidermal cells are connected via desmosomes and contain rough endoplasmic reticulum, free ribosomes and mitochondria. Scattered dermal glands are located beneath the cuticle and are continuous with the outside through dermal ducts and surface pores.

Modification of Pineal Ultrastructure by Exogenous Hormones

1967 ◽  
Vol 25 ◽  
pp. 170-171
Author(s):  
R. A. Turner ◽  
A. E. Rodin ◽  
D. K. Roberts
Keyword(s):  
Electron Microscopy ◽  
Endoplasmic Reticulum ◽  
Rough Endoplasmic Reticulum ◽  
Estradiol Benzoate ◽  
Female Rats ◽  
List Type ◽  
Type Number ◽  
Pregnant Rats ◽  
Gonadal Atrophy ◽  
Pineal Ultrastructure

There have been many reports which establish a relationship between the pineal and sexual structures, including gonadal hypertrophy after pinealectomy, and gonadal atrophy after injection of pineal homogenates or of melatonin. In order to further delineate this relationship the pineals from 5 groups of female rats were studied by electron microscopy:ControlsPregnant ratsAfter 4 weekly injections of 0.1 mg. estradiol benzoate.After 8 daily injections of 150 mcgm. melatonin (pineal hormone).After 8 daily injections of 3 mg. serotonin (melatonin precursor).No ultrastructural differences were evident between the control, and the pregnancy and melatonin groups. However, the estradiol injected animals exhibited a marked increase in the amount and size of rough endoplasmic reticulum within the pineal cells.

Conversaziones 1974

1975 ◽  
Vol 29 (2) ◽  
pp. 163-171
Keyword(s):  
Electron Microscopy ◽  
Fine Structure ◽  
Cell Walls ◽  
Structural Changes ◽  
Vascular Tissue ◽  
Root Systems ◽  
Plant Roots ◽  
Tracer Studies ◽  
Water Move ◽  
Intact Root

CONVERSAZIONES were held this year on 9 May and 27 June. At the first conversazione twenty-seven exhibits and two films were shown. The fine structure of plant roots in relation to transport of nutrient ions and water was demonstrated by Dr D. T. Clarkson of the A.R.C. Letcombe Laboratory, Wantage and Dr A. W. Robards of the Department of Biology, University of York. Two major pathways by which nutrients and water move radially across the cortex towards the central vascular tissue have been distinguished by the use of tracer studies of adsorption by different zones of intact root systems, microautoradiography and electron microscopy. Movement can be apoplastic through cell walls, or symplastic between cells joined by plasmodesmata. As the root ages, structural changes in the endodermis reduce movement in the former pathway but the symplast is not interrupted by the elaboration of endodermal walls because plasmodesmatal connexions remain intact. These observations help explain the contrasting extent to which different ions and water reach the shoot from young and mature parts of root systems.

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.

Development of the lateral palatal brush in larvae of Aedes aegypti (L.) (Diptera: Culicidae)

1990 ◽  
Vol 68 (7) ◽  
pp. 1454-1467 ◽  
Author(s):  
K. M. Fry ◽  
S. B. McIver
Keyword(s):  
Electron Microscopy ◽  
Endoplasmic Reticulum ◽  
Plasma Membrane ◽  
Golgi Apparatus ◽  
Aedes Aegypti ◽  
Rough Endoplasmic Reticulum ◽  
Light And Electron Microscopy ◽  
Fourth Instar ◽  
Muscle Fibres ◽  
Final Length

Light and electron microscopy were used to observe development of the lateral palatal brush in Aedes aegypti (L.) larvae. Development was sampled at 4-h intervals from second- to third-instar ecdyses. Immediately after second-instar ecdysis, the epidermis apolyses from newly deposited cuticle in the lateral palatal pennicular area to form an extensive extracellular cavity into which the fourth-instar lateral palatal brush filaments grow as cytoplasmic extensions. On reaching their final length, the filaments deposit cuticulin, inner epicuticle, and procuticle sequentially on their outer surfaces. The lateral palatal crossbars, on which the lateral palatal brush filaments insert, form after filament development is complete. At the beginning of development, the organelles involved in plasma membrane and cuticle production are located at the base and middle of the cells. As the filament rudiments grow, most rough endoplasmic reticulum, mitochondria, and Golgi apparatus move to the apex of the epidermal cells and into the filament rudiments. After formation of the lateral palatal brush filaments and lateral palatal crossbars, extensive organelle breakdown occurs. Lateral palatal brush formation is unusual in that no digestion and resorption of old endocuticle occurs prior to deposition of new cuticle. No mucopolysaccharide secretion by the lateral palatal brush epidermis was observed, nor were muscle fibres observed to attach to the lateral palatal crossbars, as has been suggested by other workers.

The fine structure of the leucocytes of the holothurian, Cucumaria miniata

1977 ◽  
Vol 55 (9) ◽  
pp. 1530-1544 ◽  
Author(s):  
A. R. Fontaine ◽  
Philip Lambert
Keyword(s):  
Stem Cells ◽  
Endoplasmic Reticulum ◽  
Fine Structure ◽  
Rough Endoplasmic Reticulum ◽  
Acid Mucopolysaccharide ◽  
Rough Er

The fine structure of amoebocytes, lymphocytes, and morula cells is described and related to their functions. Three morphological phases (bladder, transitional, and filiform) of the amoebocyte are distinguished. Their surface protrusions and activities are based on microtubule and microfilament systems and the transitional-filiform phases are functionally involved in coelomocyte aggregation. The bladder phase is phagocytic; bladder formation and activities are also microfilament based. Morula cells contain spherules composed of acid mucopolysaccharide and protein. Dilated rough endoplasmic reticulum (ER) cisternae apparently synthesize spherule material which is added by accretion. Lymphocytes have little cytoplasm and relatively few organelles, except for abundant rough ER and free ribosomes. Lymphocytes are probably stem cells for amoebocytes and morulas. These cells are compared with the leucocytes of other echinoderms.

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