The Effects of Calcium on the Ultrastructure of Cox's Orange Apples With Reference to Bitter Pit Disorder

1975 ◽  
Vol 23 (1) ◽  
pp. 55 ◽  
Author(s):  
HK Mahanty ◽  
BA Fineran
Keyword(s):  
Endoplasmic Reticulum ◽  
Electron Microscope ◽  
Microscope Study ◽  
Electron Microscope Study ◽  
Thin Sections ◽  
Golgi Bodies ◽  
Cool Storage ◽  
Bitter Pit ◽  
Intermediate Results

An electron microscope study on thin sections of epidermal, hypodermal and cortical tissues has been made of calcium-sprayed and unsprayed apples in relation to bitter pit disorder. Golgi bodies, endoplasmic reticulum, mitochondria, chromoplasts, vacuoles and groundplasm were better preserved in sprayed apples during cool storage for up to 2 months than in unsprayed samples. In unsprayed apples these organelles were often drastically changed. The nucleus remained reasonably well preserved in all samples. Apples from trees sprayed only once gave somewhat intermediate results.

An Electron-Microscope Study of the Cytoplasmic Inclusions in the Neurones of Locusta Migratoria

1962 ◽  
Vol s3-103 (62) ◽  
pp. 147-153
Author(s):  
DOREEN E. ASHHURST ◽  
J. A. CHAPMAN
Keyword(s):  
Endoplasmic Reticulum ◽  
Electron Microscope ◽  
Microscope Study ◽  
Electron Microscope Study ◽  
Locusta Migratoria ◽  
Cytoplasmic Inclusions ◽  
Double Membrane

The cytoplasmic inclusions of the neurones of adult Locusta migratoria have been examined in the electron microscope. The mitochondria are easily recognized by their cristae and outer double membranes. Electron-dense inclusions, also with an outer double membrane but possessing numerous closely spaced internal lamellae in various orientations, are probably small lipochondria. Larger and more diffuse inclusions comprising crescent-shaped aggregates of loosely packed parallel lamellae and vesicles are present; the possible significance of these larger inclusions is discussed. A system of numerous small vesicles distributed throughout the cytoplasm makes up the endoplasmic reticulum.

Desiccation causes the proliferation of multicellular hairs, but not mucilage papillae, in Cryptothallus mirabilis (Hepatophyta): a correlated light and electron microscope study

1990 ◽  
Vol 68 (3) ◽  
pp. 697-706 ◽  
Author(s):  
Jeffrey G. Duckett ◽  
Karen S. Renzaglia ◽  
Keith Pell
Keyword(s):  
Endoplasmic Reticulum ◽  
Electron Microscope ◽  
Acid Phosphatase ◽  
Endophytic Fungus ◽  
Electron Microscope Study ◽  
Secretory Phase ◽  
Golgi Bodies ◽  
Dense Cytoplasm ◽  
Thin Walled ◽  
Multicellular Hair

When Cryptothallus dries out over periods of 4–20 days, the dorsal surfaces of the thalli become covered with multicellular hairs. The distribution of mucilage papillae and the endophytic fungus are not affected by desiccation. The hairs are thin walled and highly vacuolated whereas the mucilage papillae, like their secretory counterparts in Marchantia and mosses, are thick walled with dense cytoplasm containing stacks of endoplasmic reticulum and numerous Golgi bodies. Cytochemistry shows that the secretion is rich in carbohydrates and is derived from Golgi vesicles. After an active secretory phase, senescence of the mucilage papillae is associated with acid phosphatase activity. Key words: Aneura, Cryptothallus, desiccation, liverwort, mucilage papilla, multicellular hair, ultrastructure.

scholarly journals An Electron Microscope Study of the Contractile Vacuole in Tokophrya infusionum

1958 ◽  
Vol 4 (2) ◽  
pp. 195-202 ◽  
Author(s):  
Maria A. Rudzinska
Keyword(s):  
Electron Microscope ◽  
Blood Cells ◽  
Microscope Study ◽  
Electron Microscope Study ◽  
Vacuolar Membrane ◽  
Contractile Vacuole ◽  
Thin Sections ◽  
Mode Of Operation ◽  
Contractile Vacuoles ◽  
Elaborate Structure

Contractile vacuoles are organelles that collect fluid from the cytoplasm and expel it to the outside. After each discharge (systole), they appear again and expand (diastole). They are widely distributed among Protozoa, and have been found also in some fresh water algae, sponges, and recently in some blood cells of the frog, guinea pig, and man. In spite of the extensive work on the contractile vacuole, very little is known concerning its mode of operation. An electron microscope study of a suctorian Tokophrya infusionum provided an opportunity to study thin sections of contractile vacuoles, and in these some structures were found which could be part of a mechanism for the systolic and diastolic motions the organelle displays. In Tokophrya, as in Suctoria and Ciliata in general, the contractile vacuole has a permanent canal connecting it with the outside. The canal appears to have a very elaborate structure and is composed of three parts: (1) a pore; (2) a channel; and (3) a narrow tubule located in a papilla protruding into the cavity of the contractile vacuole. Whereas the pore and channel have fixed dimensions and are permanently widely open, the tubule has a changeable diameter. At diastole it is so narrow (about 25 to 30 mµ in diameter) that it could be regarded as closed, while at systole it is widely open. It is assumed that the change in diameter is due to the contraction of numerous fine fibrils (about 180 A thick) which are radially disposed around the canal in form of a truncated cone, with its tip at the channel, and its base at the vacuolar membrane. It seems most probable that the broadening of the tubule results in discharge of the content of the contractile vacuole. In the vicinity of the very thin limiting vacuolar membrane, small vesicles and canaliculi of the endoplasmic reticulum, very small dense particles, and mitochondria may be found. In addition, rows of closely packed vesicles are present in this region, and in other parts of the cytoplasm. It is suggested that they might represent dictyosome-like bodies, responsible for withdrawing fluids from the cytoplasm and then conveying them to the contractile vacuole, contributing to its expansion at diastole.

scholarly journals AN ELECTRON MICROSCOPE STUDY OF YOLK FORMATION DURING OOGENESIS IN LEBISTES RETICULATUS GUPPYI

1966 ◽  
Vol 28 (2) ◽  
pp. 209-232 ◽  
Author(s):  
Michael J. Droller ◽  
Thomas F. Roth
Keyword(s):  
Endoplasmic Reticulum ◽  
Electron Microscope ◽  
Microscope Study ◽  
Electron Microscope Study ◽  
Structural Changes ◽  
Extracellular Material ◽  
Yolk Formation ◽  
Selective Uptake ◽  
Lebistes Reticulatus

The present investigation describes the fine structural changes that occur during proteid yolk formation in the developing oocytes of the guppy (Lebistes reticulatus), an ovoviviparous teleost. These changes suggest the operation of a number of different intra- and extraoocyte processes that may account for the synthesis and deposition of the proteid yolk. Early in oogenesis, the egg's Golgi systems proliferate and begin to disclose an electron-opaque content. Numerous 70-mµ diameter vesicles apparently pinch off from the Golgi systems, transport this material through the egg, and probably then fuse to form a crenate, membrane-limited yolk droplet. At the same time, the rough-surfaced endoplasmic reticulum accumulates a flocculent substance that differs in appearance from the Golgi content. Smooth vesicles, presumably derived from the ER, then coalesce to form a second type of intraoocyte yolk droplet. These dissimilar, separately derived droplets subsequently fuse, thus combining the materials that constitute the intraoocyte contribution to the proteid yolk. Somewhat later in development, the egg appears to ingest extracellular material via 75-mµ diameter bristle-coated micropinocytotic pits and vesicles. These structures apparently fuse to form tubules which then coalesce into large yolk droplets. At a later stage, bristle-coated micropinocytotic vesicles of 100 mµ diameter presumably take up a material that is then probably immediately deposited into a second type of proteid yolk droplet. It is postulated that these two different micropinocytotic structures are specifically involved with the selective uptake of dissimilar extracellular proteid materials.

An electron microscope study of the internal structure of casein micelles

1964 ◽  
Vol 31 (1) ◽  
pp. 121-123 ◽  
Author(s):  
P. D. Shimmin ◽  
R. D. Hill
Keyword(s):  
Molecular Weight ◽  
Electron Microscope ◽  
Internal Structure ◽  
Microscope Study ◽  
Electron Microscope Study ◽  
Casein Micelles ◽  
Thin Sections

SummaryA study of casein micelles was made with the electron microscope, using very thin sections cut from micelles embedded in Araldite. The micelles appear to be built up of units that are approximately spherical, about 100 Å in diameter and of about 300000 molecular weight.

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