Freeze-Fracture Replication in the Ultrastructure of Blue-Green Algae

1967 ◽  
Vol 25 ◽  
pp. 74-75
Author(s):  
L. V. Leak
Keyword(s):  
Cell Wall ◽  
Electron Microscope ◽  
Green Algae ◽  
Three Dimensional ◽  
Freeze Fracture ◽  
Electron Microscopic ◽  
Photosynthetic Membranes ◽  
Blue Green Algae ◽  
Cell Biol ◽  
Cellular Components

Electron microscopic observations of freeze-fracture replicas of Anabaena cells obtained by the procedures described by Bullivant and Ames (J. Cell Biol., 1966) indicate that the frozen cells are fractured in many different planes. This fracturing or cleaving along various planes allows one to gain a three dimensional relation of the cellular components as a result of such a manipulation. When replicas that are obtained by the freeze-fracture method are observed in the electron microscope, cross fractures of the cell wall and membranes that comprise the photosynthetic lamellae are apparent as demonstrated in Figures 1 & 2.A large portion of the Anabaena cell is composed of undulating layers of cytoplasm that are bounded by unit membranes that comprise the photosynthetic membranes. The adjoining layers of cytoplasm are closely apposed to each other to form the photosynthetic lamellae. Occassionally the adjacent layers of cytoplasm are separated by an interspace that may vary in widths of up to several 100 mu to form intralamellar vesicles.

scholarly journals ELECTRON MICROSCOPE STUDIES ON BLUE-GREEN ALGAE

1961 ◽  
Vol 9 (1) ◽  
pp. 63-80 ◽  
Author(s):  
Hans Ris ◽  
R. N. Singh
Keyword(s):  
Electron Microscope ◽  
Green Algae ◽  
Animal Cell ◽  
General Pattern ◽  
The Other ◽  
Thin Sections ◽  
Double Membrane ◽  
Photosynthetic Membranes ◽  
Blue Green Algae ◽  
Developmental States

Several species of blue-green algae were studied in thin sections with the electron microscope. Our electron micrographs confirm the view that the cell of blue-green algae is different and simpler in organization than the typical plant or animal cell. On the other hand, the general pattern of ultrastructure is the same as that found in bacteria and Streptomyces. The cell boundary is formed by a double membrane which consists of two typical unit membranes. Situated in between these membranes is the dense inner investment or wall which continues uninterrupted into the cross-walls. The cells always contain photosynthetic lamellae, nucleoplasm with DNA, small granules resembling ribosomes, and often also a number of larger granules of various sorts. The photosynthetic membranes either form the boundary of vesicles or flattened sacs, or, when the lumen of the vesicles disappears and the vesicular surfaces of the membranes zip together, they appear as lamellae made of two closely applied unit membranes. These vesicles or lamellae are disposed irregularly through the cell or arranged in parallel stacks of two or more. A thin layer of cytoplasm always separates the lamellae. The nucleoplasm is composed of masses of fine fibrils about 25 A thick and is either dispersed through the cell or concentrated in polymorphous reticular structures near the center of the cell. The improved resolution of the electron microscope makes it obvious that the terms "chromatoplasm" and "centroplasm" commonly used in the description of blue-green algae are really misleading. There are not different kinds of cytoplasm, but the cell consists of various structural (and functional) units like the ones mentioned above, which are arranged in the cell in a number of ways characteristic for each species or for different physiological or developmental states.

The heterocysts of blue-green algae I. Ultrastructural integrity after isolation

1971 ◽  
Vol 178 (1051) ◽  
pp. 185-192 ◽  
Keyword(s):  
Cell Wall ◽  
Electron Microscope ◽  
Internal Structure ◽  
Green Algae ◽  
Osmotic Shock ◽  
Anabaena Cylindrica ◽  
Vegetative Cells ◽  
Blue Green Algae ◽  
Mechanical Disruption ◽  
Physiological Properties

The heterocysts of Anabaena cylindrica were freed from filaments by differential disruption of vegetative cells using four techniques: mechanical disruption by French press, sonication, osmotic shock and lysozyme. The ultrastructure of isolated heterocysts was compared with that of heterocysts in intact filaments. The first three methods produced heterocysts whose internal structure showed different degrees of damage, involving in particular disruption of the heterocyst cell wall and plasmalemma. Isolation by the lysozyme method yielded heterocysts which appeared in the electron microscope to be intact and comparable with those of the untreated controls. These results suggest that earlier reports on the physiological properties of heterocysts isolated by means of the French press or sonication may require re-examination.

A study of several blue-green algae in the electron microscope

1962 ◽  
Vol 44 (3) ◽  
pp. 311-322 ◽  
Author(s):  
J. A. Chapman ◽  
M. R. J. Salton
Keyword(s):  
Electron Microscope ◽  
Green Algae ◽  
Blue Green Algae

Improved staining of extracellular polymer surrounding Eucapsis sp. and Anabena cylindrica: a comparative study

1974 ◽  
Vol 20 (5) ◽  
pp. 735-738
Author(s):  
Gerald D. Cagle
Keyword(s):  
Electron Microscope ◽  
Comparative Study ◽  
Green Algae ◽  
Freeze Drying ◽  
Ruthenium Red ◽  
Blue Green Algae ◽  
Modified Method ◽  
Ruthenium Red Staining ◽  
Extracellular Polymer

Extracellular polymer surrounding two blue-green algae, Eucapsis sp. (No. 1519) and Anabena cylindrica Lemm. (No. 629), was examined with the electron microscope. Conventional glutaraldehyde–OsO4 fixation, freeze-drying before fixation, and two ruthenium red staining procedures (Luft's method and the modified method of Cagle et al.) were used. The data obtained indicate that observation of extracellular polymer is successively enhanced over conventional fixation when (i) freeze-drying, (ii) Luft's ruthenium red method, and (iii) the modified method of Cagle et al. are used. Each of the methods was also observed to improve cytological detail, particularly in A. cylindrica.

Three-Dimensional Computational Hydrodynamics Modeling for Algae Transport and Growth

2017 ◽  
Author(s):  
Haidong Liu ◽  
Zhongquan Charlie Zheng ◽  
Bryan Young
Keyword(s):  
Green Algae ◽  
Hydrodynamic Model ◽  
Algal Blooms ◽  
Stokes Equations ◽  
Transport Model ◽  
Three Dimensional ◽  
Dimensional Model ◽  
Three Dimensional Model ◽  
Fractional Step Method ◽  
Blue Green Algae

In this study, a three-dimensional model coupling hydrodynamics with algae transport dynamics is investigated. The hydrodynamic model solves the three-dimensional Navier-Stokes equations by a semi-implicit, fractional step method, where the hydrostatic components are determined first and the non-hydrostatic pressure and other components are determined in a subsequent step. Wind velocity on the water surface is accounted for the effect of wind stress on the flow velocities in the hydrodynamic model. Then, the model is coupled with an algae transport model, which enables simulation of algae transport and algal blooms. As an example, the model is implemented to analyze the transition of blue-green algae in Milford Lake, which is the largest man-made lake in Kansas suffering from blue-green algae blooms. The three-dimensional model provides a robust and efficient way for hydrodynamic and algae modeling and can be implemented to studies on different types of rivers and reservoirs easily. The simulated results can be very useful for algae control and prediction in both short and long terms.

Structural Variations of Polyphosphate Bodies in Blue-Green Algae

1972 ◽  
Vol 30 ◽  
pp. 218-219
Author(s):  
Linda M. Sicko
Keyword(s):  
Green Algae ◽  
Culture Media ◽  
Electron Microscopic Examination ◽  
Culture Conditions ◽  
Structural Variations ◽  
Electron Microscopic ◽  
Blue Green Algae ◽  
Stage Of Development ◽  
Wide Range ◽  
Polyphosphate Bodies

Polyphosphate appears to be a ubiquitous component of all microorganisms. Electron microscopic examination of blue-green algae reveals bodies which are usually spherical, and have a wide range of electron densities. From work conducted in our laboratory, it appears that the image of the polyphosphate bodies varies with the culture conditions as well as the stage of development under constant culture conditions. The following report describes the various images one can observe.For most experiments, the blue-green algae were fixed by the method of Pankratz and Bowen. The algae were pelleted, the culture media poured off, and the pellet was resuspended in 1% OsO4 buffered at pH 6.2 for 3 hours at room temperature.

scholarly journals Electron Microscopic Observations on the Three-Dimensional Morphology of Apatite Crystallites of Human Dentine and Bone'

1960 ◽  
Vol 7 (4) ◽  
pp. 743-746 ◽  
Author(s):  
Erling Johansen ◽  
Harold F. Parks
Keyword(s):  
Electron Microscope ◽  
Three Dimensional ◽  
Cylindrical Shape ◽  
Electron Microscopic ◽  
3 Dimensional ◽  
Specimen Holder ◽  
Thin Profile ◽  
Human Dentine

In sections of human dentine (carious and sound) and bone examined with the electron microscope, apatite crystallites were seen to present long thin profiles somewhat suggestive of a cylindrical shape, broad profiles indicative of a plate-like shape, and profiles intermediate between these two extremes. With a special stereoscopic specimen holder allowing the specimen to be tilted through an angle of 30° it was possible to record images of two profiles of the same crystallite from different angles and thus gain information concerning the 3-dimensional morphology of crystallites showing a thin profile. In all fields so examined, the thin-profile crystallites that were properly oriented with respect to the axis of tilt exhibited a different width dimension in each of the two micrographs. From this it is concluded that the thin profiles actually represented edge views of plate-like crystallites.

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