Influence de la température et de la durée d'un traitement cryoprotecteur sur la résistance au froid de plantules de blé. Étude ultrastructurale des ébauches foliaires

1983 ◽  
Vol 61 (4) ◽  
pp. 1025-1039 ◽  
Author(s):  
C. M. Gazeau
Keyword(s):  
Endoplasmic Reticulum ◽  
Treatment Period ◽  
Day Treatment ◽  
Leaf Primordia ◽  
Ultrastructural Changes ◽  
Distilled Water ◽  
Wheat Seedlings ◽  
Starch Grains ◽  
Different Temperatures ◽  
Protective Treatment

Wheat seedlings were treated at different temperatures and for various periods of time with a cold-protective substance, composed of a mixture of glycerol, dimethylsulfoxide, and saccharose. When the treatment was done at 20 °C, slight ultrastructural changes appeared in leaf primordia as soon as day 1. Thus numbers of lipid globules increased significantly. When the treatment period was increased to 4 days, numbers of starch grains increased, and there was a marked enlargement of mitochondria and plasts. When the treatment was done at 2 °C, cytoplasmic alterations occurred later than at 20 °C. After a 4-day treatment, they were similar to changes induced at 20 °C. When the treatment period was increased to 12 days, dictyosomes were markedly altered. They clustered close to the nucleus in two or three groups and gave rise to numerous pale vesicles with various shapes and sizes. Around each cluster of such vesicles, there gathered many endoplasmic reticulum vesicles and other organelles (mitochondria, plasts, microbodies, vacuoles). A further cooling of 1 °C/min, down to −15 or −30 °C, enhanced these phenomena. After the seedlings were warmed up to 20 °C in distilled water, the changes induced by the frost-protective treatment and then by freezing were shown to be reversible. [Journal translation]

Ultrastructural changes in shoot apex cells of winter wheat seedlings during ice encasement

1978 ◽  
Vol 56 (7) ◽  
pp. 786-794 ◽  
Author(s):  
M. Keith Pomeroy ◽  
Chris J. Andrews
Keyword(s):  
Endoplasmic Reticulum ◽  
Winter Wheat ◽  
Structural Integrity ◽  
Triticum Aestivum L ◽  
Ultrastructural Changes ◽  
Wheat Seedlings ◽  
Contrast Exposure ◽  
Ice Encasement ◽  
Cold Hardy ◽  
Cellular Organelles

The decline in viability of cold-hardy Kharkov winter wheat (Triticum aestivum L.) seedlings during ice encasement at −1 °C was accompanied by characteristic ultrastructural changes. A dramatic increase in endoplasmic reticulum was observed within a few days. This proliferation of endoplasmic reticulum often resulted in the formation of an elaborate series of parallel membranes, either dispersed randomly throughout the cytoplasm or in the form of concentric whorls. However, the structural integrity of many cellular organelles was largely unaffected even by prolonged ice encasement resulting in death of the plants. In contrast, exposure of cold-hardy seedlings to near lethal, subfreezing temperature resulted in severe disorganization of cellular organelles. Ice encasement of nonhardened seedlings resulted in complete kill within 4 h. After 16 h ice encasement, occasional concentric whorls of endoplasmic reticulum and copious amounts of osmiophilic material were observed in the cytoplasm. Upon removal of the ice encasement stress, the accumulated endoplasmic reticulum disappeared rapidly during recovery at either2 or20 °C.

Influence de la température et de la durée d'un traitement cryoprotecteur sur la résistance au froid de plantules de blé. Étude ultrastructurale des nucléoles des ébauches foliaires

1985 ◽  
Vol 63 (4) ◽  
pp. 663-671 ◽  
Author(s):  
Claude-Madeleine Gazeau
Keyword(s):  
Dimethyl Sulfoxide ◽  
Low Temperatures ◽  
Leaf Primordia ◽  
Distilled Water ◽  
Wheat Seedlings ◽  
Cryoprotective Agent

The nucleolus is sensitive to cold-protective media and to low temperatures. Nucleolar changes observed in the leaf primordia of wheat seedlings were related to the impregnation medium (distilled water or a mixture of glycerol, dimethyl sulfoxide, and sucrose), to the temperature (20 or 2 °C), and to the duration of the pretreatment (1 to 12 days). The cryoprotective agent generated the formation of nucleoli "with a diffuse granular zone." If the impregnation was done at 2 °C, characteristic nucleoli "with an indented aspect" occurred. The longer the duration of the impregnation and the more intense the subsequent freezing, the more important were the nucleolar changes. On rewarming the seedlings the various transformations were shown to be reversible.

Accroissement de la résistance au froid (jusqu'à −30 °C) de plantules de Blé avec un milieu cryoprotecteur. Effets de ce traitement sur les ultrastructures de cellules parenchymateuses d'ébauches foliaires

1980 ◽  
Vol 58 (23) ◽  
pp. 2520-2532 ◽  
Author(s):  
C. M. Gazeau
Keyword(s):  
Leaf Primordia ◽  
Cold Temperature ◽  
Ultrastructural Changes ◽  
Wheat Seedlings ◽  
Parenchyma Cells ◽  
Mitotic Figures ◽  
Peripheral Cytoplasm ◽  
Peripheral Regions

Wheat seedlings treated with a frost-protecting medium containing a mixture of glycerol, dimethyl sulfoxyde, and saccharose, were subjected to cooling at the rate of 1 °C/min during a few hours. Seedlings treated in this way were resistant to temperatures of −30 °C. However on rewarming, the growth of leaves and coleoptiles was slightly slowed down compared with that of control seedlings.Seedling impregnation with the frost-protecting medium provoked few ultrastructural changes in the parenchyma cells of leaf primordia. Only lipidic, osmiophilic globules were relatively abundant, and these were scattered in the peripheral cytoplasm, along the plasmalemma. Cooling to −30 °C tended to make certain organelles migrate preferentially towards peripheral regions; the plasmalemma, osmiophilic globules, microtubules, and mitochondria came into contact with each other. In spite of the very cold temperature, some mitotic figures persisted with no evident signs of changes.On rewarming the seedlings, the various changes observed during cold treatments gradually diminished and disappeared. [Journal translation]

Ultrastructural Changes Associated with Alcoholic Hyalin in Hepatocytes and Biliary Epithelial Cells

1971 ◽  
Vol 29 ◽  
pp. 572-573
Author(s):  
Odell T. Minick ◽  
Hidejiro Yokoo ◽  
Fawzia Batti
Keyword(s):  
Endoplasmic Reticulum ◽  
Epithelial Cells ◽  
Liver Biopsy ◽  
Alcoholic Hepatitis ◽  
Ultrastructural Changes ◽  
Main Mass ◽  
Biliary Epithelial Cells ◽  
Biopsy Specimens ◽  
Alcoholic Hyalin

To learn more of the nature and origin of alcoholic hyalin (AH), 15 liver biopsy specimens from patients with alcoholic hepatitis were studied in detail.AH was found not only in hepatocytes but also in ductular cells (Figs. 1 and 2), although in the latter location only rarely. The bulk of AH consisted of a randomly oriented network of closely packed filaments measuring about 150 Å in width. Bundles of filaments smaller in diameter (40-90 Å) were observed along the periphery of the main mass (Fig. 1), often surrounding it in a rim-like fashion. Fine filaments were also found close to the nucleus in both hepatocytes and biliary epithelial cells, the latter even though characteristic AH was not present (Figs. 3 and 4). Dispersed among the larger filaments were glycogen, RNA particles and profiles of endoplasmic reticulum. Dilated cisternae of endoplasmic reticulum were often conspicuous around the periphery of the AH mass. A limiting membrane was not observed.

Ultrastructural Changes of Smoooth Endoplasmic Reticulum in the Retinal Pigment Epithelium by Choline Chloride

1972 ◽  
Vol 30 ◽  
pp. 58-59
Author(s):  
Kazushige Hirosawa ◽  
Eichi Yamada
Keyword(s):  
Endoplasmic Reticulum ◽  
Epithelial Cell ◽  
Smooth Endoplasmic Reticulum ◽  
Pigment Epithelium ◽  
Choline Chloride ◽  
Retinal Pigment ◽  
Ultrastructural Changes ◽  
Lower Vertebrate ◽  
Visual Cells ◽  
Pigment Epithelial

The pigment epithelium is located between the choriocapillary and the visual cells. The pigment epithelial cell is characterized by a large amount of the smooth endoplasmic reticulum (SER) in its cytoplasm. In addition, the pigment epithelial cell of some lower vertebrate has myeloid body as a specialized form of the SER. Generally, SER is supposed to work in the lipid metabolism. However, the functions of abundant SER and myeloid body in the pigment epithelial cell are still in question. This paper reports an attempt, to depict the functions of these organelles in the frog retina by administering one of phospholipid precursors.

TEMPERATURE IN RELATION TO THE TRANSMISSION AND PATHOGENICITY OF WHEAT STRIATE MOSAIC VIRUS

1964 ◽  
Vol 42 (9) ◽  
pp. 1123-1133 ◽  
Author(s):  
J. T. Slykhuis ◽  
P. L. Sherwood
Keyword(s):  
Mosaic Virus ◽  
Incubation Period ◽  
Spring Wheat ◽  
Early Summer ◽  
Wheat Seedlings ◽  
Acquisition Access Period ◽  
The North ◽  
Different Temperatures ◽  
North American Type ◽  
Test Plants

Endria inimica Say acquired the North American type of wheat striate mosaic virus during periods of 15 minutes or longer on diseased plants held at five constant temperatures ranging from 10 to 33 °C. When infective insects were given inoculation access periods varying from 1 to 4 days at different temperatures, the percentage of test plants infected increased with temperature from 12.5% at 10° to 81.4% at 33 °C. After an acquisition access period of 2 days at 24 °C, insects kept at 8 or 10 °C did not transmit virus, but the percentage of others that transmitted at successively higher temperatures increased from 3.3% at 16 °C to 73.3% at 33 °C. The preinfective period was more than 29 days for insects kept at 16 °C and only 5 days for some kept at 27, 30, and 33 °C. The average preinfective period was 11 days at 20 °C, but decreased to 6.4 days as temperature increased to 33 °C. The percentage of test plants that became infected increased from 0.1% at 16 °C to 44.3%, at 33 °C. Stewart and Ramsey wheat seedlings exposed to infective E. inimica for 2 days did not develop symptoms during a subsequent 60 day period at 10 °C. After the same plants were placed in a greenhouse at 20–25 °C, 26% and 27%, respectively, developed symptoms. The incubation period for symptoms in plants ranged from 17 to more than 62 days at 16 °C. It decreased as temperature increased but varied from 6 to 25 days at 30 °C. Forty-two and 48% of Stewart and Ramsey wheat plants respectively, developed symptoms at 16 °C, and increased to almost 100% for both varieties at 30 and 33 °C. The above results indicate that high temperatures during early summer are prerequisite for severe epidemics of wheat striate mosaic in spring wheat.

scholarly journals Ultrastructural Changes in the Pancreata of Selenium-Vitamin E-Deficient Chicks

1977 ◽  
Vol 14 (6) ◽  
pp. 629-642 ◽  
Author(s):  
A. H. Rebar ◽  
J. F. Van Vleet
Keyword(s):  
Endoplasmic Reticulum ◽  
Vitamin E ◽  
Acinar Cell ◽  
Interstitial Fibrosis ◽  
Ultrastructural Changes ◽  
Zymogen Granules ◽  
Cell Cytoplasm ◽  
Torula Yeast ◽  
Cell Changes ◽  
Ductular Proliferation

Three hundred and seventy 1-day-old male, white Leghorn chicks were divided into seven groups and fed a series of semipurified torula yeast diets either deficient in or supplemented with selenium and vitamin E. Chicks in each group were necropsied sequentially and the pancreata examined by light microscopy. Selected pancreata of selenium deficient chicks in various stages of the deficiency disease were examined by electron microscopy. Supplements of either selenium (0.2 mg/kg) or vitamin E (100 IU/kg diet) resulted in protection against pancreatic lesions. Changes in pancreata of selenium deficient chicks progressed from cytoplasmic vacuolation of acinar cell cytoplasm to focal disseminated acinar necrosis. There was ductular proliferation and interstitial fibrosis in advanced lesions. Acini around islets were less frequently affected than acini further away. Ultrastructurally, the mildest lesions were focal dilation of the endoplasmic reticulum and autophagic vacuoles in acinar cell cytoplasm. Necrotic areas contained both membranous and granular debris and fragments of intact endoplasmic reticulum. In fibrotic pancreata the main acinar cell changes were uniform dilation of endoplasmic reticulum and reduction in number of zymogen granules.

scholarly journals Pollen, Tapetum, and Orbicule Development inColletia paradoxaandDiscaria americana(Rhamnaceae)

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
M. Gotelli ◽  
B. Galati ◽  
D. Medan
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Endoplasmic Reticulum ◽  
Pollen Grains ◽  
Pollen Grain ◽  
Ultrastructural Changes ◽  
Transmission Electron ◽  
The Family ◽  
Tapetal Cells ◽  
Grain Formation

Tapetum, orbicule, and pollen grain ontogeny inColletia paradoxaandDiscaria americanawere studied with transmission electron microscopy (TEM). The ultrastructural changes observed during the different stages of development in the tapetal cells and related to orbicule and pollen grain formation are described. The proorbicules have the appearance of lipid globule, and their formation is related to the endoplasmic reticulum of rough type (ERr). This is the first report on the presence of orbicules in the family Rhamnaceae. Pollen grains are shed at the bicellular stage.

Enhancement of FSH bioactivity in vivo using site-specific antisera

1997 ◽  
Vol 152 (3) ◽  
pp. 355-363 ◽  
Author(s):  
L Ferasin ◽  
G Gabai ◽  
J Beattie ◽  
G Bono ◽  
A T Holder
Keyword(s):  
Biological Activity ◽  
Treatment Period ◽  
Ovarian Function ◽  
Day Treatment ◽  
Site Specific ◽  
Dose Dependent Fashion ◽  
Snell Dwarf ◽  
Fsh Bioactivity ◽  
Dose Dependent

The ability of site-specific antipeptide antisera to enhance the biological activity of ovine FSH (oFSH) in vivo was investigated using hypopituitary Snell dwarf mice. These animals were shown to respond to increasing doses of oFSH (3·3–90 μg/day), administered in two daily injections over a 5-day treatment period, in a highly significant dose-dependent fashion. The responses measured were increases in uterine weight, ovarian weight and the index of keratinisation in vaginal smears. The dose-dependent response to oFSH confirmed the suitability of this animal model for these investigations and suggested the suboptimal dose of oFSH (20 μg/day) for use in enhancement studies. Five peptides derived from the β subunit of bovine FSH (bFSH) (A, residues 33–47; B, 40–51; C, 69–80; D, 83–94; E, 27–39) were used to generate polyclonal antipeptide antisera. Of these peptides, only A and B produced an antiserum (raised in sheep) capable of recognising 125I-bFSH in a liquid phase RIA. Antisera prepared against peptide A or peptide B were found to significantly enhance the biological activity of 20 μg oFSH/day over a 5-day treatment period. The response to antipeptide antisera alone did not differ significantly from that observed in PBS-injected control animals, neither did the response to FSH alone differ from that observed in animals treated with FSH plus preimmune serum. Thus the enhanced responses are dependent upon the presence of FSH plus antipeptide antiserum. Peptides A and B are located in a region thought to be involved in receptor recognition, this may have implications for the mechanism underlying this phenomenon and/or the structure/function relationships of FSH. That FSH-enhancing antisera can be generated by immunisation of animals with peptides A and B suggests that it may be possible to develop these peptides as vaccines capable of increasing reproductive performance, such as ovulation rate. The high degree of sequence homology between ovine, bovine and porcine (and to a lesser extent human and equine) FSH in the region covered by peptides A and B suggests that these peptides could also be used to promote and regulate ovarian function in all of these species. Journal of Endocrinology (1997) 152, 355–363

scholarly journals Clonal Tests of Conventional Kinesin Function during Cell Proliferation and Differentiation

2000 ◽  
Vol 11 (4) ◽  
pp. 1329-1343 ◽  
Author(s):  
Robert P. Brendza ◽  
Kathy B. Sheehan ◽  
F.R. Turner ◽  
William M. Saxton
Keyword(s):  
Cell Proliferation ◽  
Endoplasmic Reticulum ◽  
Heavy Chain ◽  
Larval Instar ◽  
Vesicle Transport ◽  
Ultrastructural Changes ◽  
Chain Gene ◽  
Cell Periphery ◽  
Kinesin Heavy Chain ◽  
Conventional Kinesin

Null mutations in the Drosophila Kinesin heavy chain gene (Khc), which are lethal during the second larval instar, have shown that conventional kinesin is critical for fast axonal transport in neurons, but its functions elsewhere are uncertain. To test other tissues, single imaginal cells in young larvae were rendered null for Khc by mitotic recombination. Surprisingly, the null cells produced large clones of adult tissue. The rates of cell proliferation were not reduced, indicating that conventional kinesin is not essential for cell growth or division. This suggests that in undifferentiated cells vesicle transport from the Golgi to either the endoplasmic reticulum or the plasma membrane can proceed at normal rates without conventional kinesin. In adult eye clones produced by null founder cells, there were some defects in differentiation that caused mild ultrastructural changes, but they were not consistent with serious problems in the positioning or transport of endoplasmic reticulum, mitochondria, or vesicles. In contrast, defective cuticle deposition by highly elongated Khc null bristle shafts suggests that conventional kinesin is critical for proper secretory vesicle transport in some cell types, particularly ones that must build and maintain long cytoplasmic extensions. The ubiquity and evolutionary conservation of kinesin heavy chain argue for functions in all cells. We suggest interphase organelle movements away from the cell center are driven by multilayered transport mechanisms; that is, individual organelles can use kinesin-related proteins and myosins, as well as conventional kinesin, to move toward the cell periphery. In this case, other motors can compensate for the loss of conventional kinesin except in cells that have extremely long transport tracks.

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