Diversity of Sperm Cell Architecture in Ferns

Among land plants, lower vascular plants produce the most elaborate of all male gametes. in order to characterize the degree of variability in sperm cell architecture among ferns, this scanning electron microscope study was undertaken on three highly disparate genera: Ceratopteris(a derived leptosporangiate fern) Angiopteris(a derived eusporangiate fern) and Psilotum(a putatively basal eusporangiate fern).Mature gametophytes were placed in 0.01M phosphate buffer (pH ca. 7.2) or distilled water until spermatozoids were released. Gametophyte portions were removed and the spermatozoid suspension fixed with 2% glutaraldehyde in 0.05M phosphate buffer. Post-fixation utilized 1% aqueous osmium tetroxide for lhr, followed by rinsing and dehydration in ethanol (10 min @ 25, 50, 75 and 100%). The dehydrated pellet was suspended in 100% hexamethyldisilazane, immediately centrifuged and the pellet deposited onto clean glass coverslips. Specimens were dried at 60°C, sputtered with ca. 350 A of palladium/gold and imaged in a Hitachi S570 SEM.

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Spontaneous Cataract in Nude Athymic Mice

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100079991 ◽

1977 ◽

Vol 35 ◽

pp. 512-513

Author(s):

Ronald H. Bradley ◽

R. S. Berk ◽

L. D. Hazlett

Keyword(s):

Electron Microscopy ◽

Scanning Electron Microscopy ◽

Nude Mouse ◽

Cellular Immunity ◽

Phosphate Buffer ◽

Osmium Tetroxide ◽

Athymic Mice ◽

Transmission Microscopy ◽

Mouse Lens ◽

Scanning Electron

The nude mouse is a hairless mutant (homozygous for the mutation nude, nu/nu), which is born lacking a thymus and possesses a severe defect in cellular immunity. Spontaneous unilateral cataractous lesions were noted (during ocular examination using a stereomicroscope at 40X) in 14 of a series of 60 animals (20%). This transmission and scanning microscopic study characterizes the morphology of this cataract and contrasts these data with normal nude mouse lens.All animals were sacrificed by an ether overdose. Eyes were enucleated and immersed in a mixed fixative (1% osmium tetroxide and 6% glutaraldehyde in Sorenson's phosphate buffer pH 7.4 at 0-4°C) for 3 hours, dehydrated in graded ethanols and embedded in Epon-Araldite for transmission microscopy. Specimens for scanning electron microscopy were fixed similarly, dehydrated in graded ethanols, then to graded changes of Freon 113 and ethanol to 100% Freon 113 and critically point dried in a Bomar critical point dryer using Freon 13 as the transition fluid.

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A Scanning Electron Microscope Study of Isolated Guard Cells

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010007271x ◽

1973 ◽

Vol 31 ◽

pp. 454-455 ◽

Cited By ~ 1

Author(s):

P. Dayanandan ◽

P. B. Kaufman

Keyword(s):

Electron Microscope ◽

Electron Microscope Study ◽

Three Dimensional ◽

Guard Cells ◽

Scanning Electron Microscope Study ◽

Psilotum Nudum ◽

Subsidiary Cells ◽

Welwitschia Mirabilis ◽

Cycas Revoluta ◽

Scanning Electron

A three dimensional appreciation of the guard cell morphology coupled with ultrastjuctural studies should lead to a better understanding of their still obscure dynamics of movement. We have found the SEM of great value not only in studies of the surface details of stomata but also in resolving the structures and relationships that exist between the guard and subsidiary cells. We now report the isolation and SEM studies of guard cells from nine genera of plants.Guard cells were isolated from the following plants: Psilotum nudum, four species of Equisetum, Cycas revoluta, Ceratozamia sp., Pinus sylvestris, Ephedra cochuma, Welwitschia mirabilis, Euphorbia tirucalli and Allium cepa.

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Resolution of Channels in the Exine by Translocation of Colloidal Iron

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100065808 ◽

1971 ◽

Vol 29 ◽

pp. 352-353

Author(s):

John R. Rowley

Keyword(s):

Phosphate Buffer ◽

Pollen Development ◽

Osmium Tetroxide ◽

Pollen Grains ◽

Deionized Water ◽

Colloidal Iron ◽

Fixed Material ◽

Epilobium Angustifolium ◽

Untreated Material ◽

Microspore Mitosis

The morphology of the exine of many pollen grains, at the time of flowering, is such that one can suppose that transport of substances through the exine occurred during pollen development. Holes or channels, microscopic to submicroscopic, are described for a large number of grains. An inner part of the exine of Epilobium angustifolium L. and E. montanum L., which may be referred to as the endexine, has irregularly shaped channels early in pollen development although by microspore mitosis there is no indication of such channeling in chemically fixed material. The nucleus in microspores used in the experiment reported here was in prophase of microspore mitosis and the endexine, while lamellated in untreated grains, did not contain irregularly shaped channels. Untreated material from the same part of the inflorescence as iron treated stamens was examined following fixation with 0.1M glutaraldehyde in cacodylate-HCl buffer at pH 6.9 (315 milliosmoles) for 24 hrs, 4% formaldehyde in phosphate buffer at pH 7.2 (1,300 milliosmoles) for 12 hrs, 1% glutaraldehyde mixed with 0.1% osmium tetroxide for 20 min, osmium tetroxide in deionized water for 2 hrs and 1% glutaraldehyde mixed with 4% formaldehyde in 0.1M cacodylate-HCl buffer at pH 6.9 for two hrs.

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Ultrastructural comparison of prolactin adenomas of pituitary in men and women

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100103796 ◽

1988 ◽

Vol 46 ◽

pp. 346-347

Author(s):

R.C. Caughey ◽

U.P. Kalyan-Raman

Keyword(s):

Endoplasmic Reticulum ◽

Electron Microscope ◽

Phosphate Buffer ◽

Pituitary Adenomas ◽

Osmium Tetroxide ◽

Secretory Granules ◽

Uranyl Acetate ◽

En Bloc ◽

Men And Women ◽

Transmission Electron

Prolactin producing pituitary adenomas are ultrastructurally characterized by secretory granules varying in size (150-300nm), abundance of endoplasmic reticulum, and misplaced exocytosis. They are also subclassified as sparsely or densely granulated according to the amount of granules present. The hormone levels in men and women vary, being higher in men; so also the symptoms vary between both sexes. In order to understand this variation, we studied 21 prolactin producing pituitary adenomas by transmission electron microscope. This was out of a total of 80 pituitary adenomas. There were 6 men and 15 women in this group of 21 prolactinomas.All of the pituitary adenomas were fixed in 2.5% glutaraldehyde, rinsed in Millonig's phosphate buffer, and post fixed with 1% osmium tetroxide. They were then en bloc stained with 0.5% uranyl acetate, rinsed with Walpole's non-phosphate buffer, dehydrated with graded series of ethanols and embedded with Epon 812 epoxy resin.

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Scanning Electron Microscope Study of Bacteria on Mineral Surfaces

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100090634 ◽

1976 ◽

Vol 34 ◽

pp. 130-131

Author(s):

V.K. Berry

Keyword(s):

Oxidation Reaction ◽

Electron Microscope Study ◽

Elemental Sulfur ◽

Thiobacillus Ferrooxidans ◽

Physical Contact ◽

Metal Sulfides ◽

Low Grade ◽

Mineral Surfaces ◽

Mineral Surface ◽

Scanning Electron Microscope Study

There are two strains of bacteria viz. Thiobacillus thiooxidansand Thiobacillus ferrooxidanswidely mentioned to play an important role in the leaching process of low-grade ores. Another strain used in this study is a thermophile and is designated Caldariella .These microorganisms are acidophilic chemosynthetic aerobic autotrophs and are capable of oxidizing many metal sulfides and elemental sulfur to sulfates and Fe2+ to Fe3+. The necessity of physical contact or attachment by bacteria to mineral surfaces during oxidation reaction has not been fairly established so far. Temple and Koehler reported that during oxidation of marcasite T. thiooxidanswere found concentrated on mineral surface. Schaeffer, et al. demonstrated that physical contact or attachment is essential for oxidation of sulfur.

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