Fine structure of the thermophilic blue-green alga Synechococcus lividus Copeland. A study of frozen–fractured–etched cells

1972 ◽  
Vol 18 (2) ◽  
pp. 175-181 ◽  
Author(s):  
S. C. Holt ◽  
M. R. Edwards
Keyword(s):  
Green Alga ◽  
Lipid Bodies ◽  
Blue Green Alga ◽  
Etching Technique ◽  
Thin Sections ◽  
Blue Green Algae ◽  
Osmiophilic Granules ◽  
Freeze Etching ◽  
The Many ◽  
Synechococcus Lividus

The thermophilic unicellular blue-green alga, Synechococcus lividus, was studied by electron microscopy in thin sections and by the freeze-etching technique. Thin sections revealed subcellular structures like those observed by other authors in mesophilic blue-green algae. In the freeze-etched fractures similar results were obtained but, in addition, surface views of plasma and thylakoidal membranes were examined in detail. The many inclusions present in the freeze-etched preparations confirmed those displayed in thin sections and are interpreted as polyhedral, polyphosphate, and lipid bodies. Some unidentified osmiophilic granules and also phycobilisomes were seen.

The Nature of Rapidly Extracted Phycocyanin from the Blue-Green Alga Plectonema Boryanum

1971 ◽  
Vol 29 ◽  
pp. 366-367
Author(s):  
M. Kessel ◽  
R. MacColl
Keyword(s):  
Self Assembly ◽  
Analytical Ultracentrifugation ◽  
Uranyl Acetate ◽  
The Self ◽  
Major Protein ◽  
Subunit Structure ◽  
Blue Green Alga ◽  
Thin Sections ◽  
Blue Green Algae ◽  
Cacodylate Buffer

The major protein of the blue-green algae is the biliprotein, C-phycocyanin (Amax = 620 nm), which is presumed to exist in the cell in the form of distinct aggregates called phycobilisomes. The self-assembly of C-phycocyanin from monomer to hexamer has been extensively studied, but the proposed next step in the assembly of a phycobilisome, the formation of 19s subunits, is completely unknown. We have used electron microscopy and analytical ultracentrifugation in combination with a method for rapid and gentle extraction of phycocyanin to study its subunit structure and assembly.To establish the existence of phycobilisomes, cells of P. boryanum in the log phase of growth, growing at a light intensity of 200 foot candles, were fixed in 2% glutaraldehyde in 0.1M cacodylate buffer, pH 7.0, for 3 hours at 4°C. The cells were post-fixed in 1% OsO4 in the same buffer overnight. Material was stained for 1 hour in uranyl acetate (1%), dehydrated and embedded in araldite and examined in thin sections.

Cellular Effects of Herbicide Simazine on Blue-Green Algae

1982 ◽  
Vol 40 ◽  
pp. 324-325
Author(s):  
R.S. Mehta ◽  
K.W. Hawxby
Keyword(s):  
Green Algae ◽  
Green Alga ◽  
Anacystis Nidulans ◽  
Blue Green Alga ◽  
Blue Green Algae ◽  
Cellular Effects

This study is sought to compare the effects of herbicide simazine (2-chloro 4,-6-bis (ethylamino)-S-triazine) on cellular corrponents of control and the treated cells of the blue-green alga (cyanobacterium) Anacystis nidulans, which are well defined and documented. The extent to which this initial interpretation of observations are realities, must be determined by biochemical and perhaps cytochemical techniques as well.

scholarly journals THE FINE STRUCTURE OF THE NUCLEAR MATERIAL OF A BLUE-GREEN ALGA, ANABAENA CYLINDRICA LEMM

1960 ◽  
Vol 8 (3) ◽  
pp. 813-823 ◽  
Author(s):  
David A. Hopwood ◽  
Audrey M. Glauert
Keyword(s):  
Fine Structure ◽  
Green Alga ◽  
Calcium Content ◽  
Nuclear Material ◽  
Blue Green Alga ◽  
Anabaena Cylindrica ◽  
Thin Sections ◽  
Central Regions ◽  
Nuclear Regions ◽  
Cellular Components

The chromatinic material of the blue-green alga Anabaena cylindrica has complex configurations in the central regions of the cells. The distribution of the chromatin within the cells varies in different filaments, probably in response to variations in the disposition of other cellular components. In electron micrographs of thin sections of organisms fixed by the method of Kellenberger, Ryter, and Séchaud (1958) the centroplasm contains fibrillar and possibly granular components which can be identified as the nuclear material by comparison with stained preparations viewed in the light microscope. The fibrils in the nuclear regions have diameters in the range of 5 to 7 mµ and are embedded in a matrix of lower density. The nuclear regions are not greatly different from the cytoplasm in their electron density. Reducing the calcium content of the fixative results in coagulation of the fibrils to form coarser structures. The significance of the observations is discussed in relation to observations on the fine structure of other classes of algae and of bacteria.

Preservation of the sheath of a blue-green alga, Anabaena flos-aquae A-37

1974 ◽  
Vol 20 (10) ◽  
pp. 1415-1416 ◽  
Author(s):  
Augustine W. Wang ◽  
R. G. Tischer
Keyword(s):  
Aqueous Solution ◽  
Elevated Temperature ◽  
Cell Surface ◽  
Green Alga ◽  
Organic Dyes ◽  
Uranyl Acetate ◽  
Blue Green Alga ◽  
Thin Sections ◽  
Low Concentration ◽  
Internal Organization

The preservation of the sheath of Anabaena flos-aquae A-37 was achieved when the growing culture was pretreated with a low concentration of glutaraldehyde and fixed using the standard Kellenberger method. The thin sections were stained with an aqueous solution of uranyl acetate at an elevated temperature. The sheath of A. flos-aquae A-37 consisted of fibrous structures and measured about 1.0–2.0 nm in diameter. The fibers were parallel with one another and to the cell surface. The method used eliminated the use of organic dyes and provided an excellent visualization of the sheath and the internal organization.

scholarly journals PHYCOBILISOMES OF THE THERMOPHILIC BLUE-GREEN ALGA SYNECHOCOCCUS LIVIDUS

1971 ◽  
Vol 50 (3) ◽  
pp. 896-900 ◽  
Author(s):  
Mercedes R. Edwards ◽  
Elisabeth Gantt
Keyword(s):  
Green Alga ◽  
Blue Green Alga ◽  
Synechococcus Lividus

Mesosome-like Structures in Cryptococcus neoformans Studied by Chemical Fixation and by the Freeze-etching Technique

1968 ◽  
Vol 26 ◽  
pp. 80-81
Author(s):  
M. R. Edwards ◽  
S. C. Holt
Keyword(s):  
Electron Microscope ◽  
Cryptococcus Neoformans ◽  
Room Temperature ◽  
Osmium Tetroxide ◽  
Chemical Fixation ◽  
Etching Technique ◽  
Pathogenic Yeast ◽  
Thin Sections ◽  
Lead Salts ◽  
Freeze Etching

The general features of Cryptococcus neoformans, a pathogenic yeast, have been studied with the electron microscope. In the course of such a study it was noted that the plasma membrane of C. neoformans, occasionally invaginated into the cytoplasm and formed membranous organelles which resembled bacterial mesosomes. The present investigation was undertaken in order to examine such structures in detail and to compare the results from chemical fixation with those of freeze-etching.Cells were grown in Sabouraud's agar at 25-27° C for 24-48 hr and fixed with 4% glutaraldehyde in 0.15 M phosphate (Sbrensen's) buffer, at room temperature, for 2 hr; after being thoroughly washed in the buffer and post-fixed in osmium tetroxide, in the same buffer, they were dehydrated in ethyl alcohol and embedded in Epon. Thin sections were cut in a LKB microtome, double stained with uranyl and lead salts and examined in the Siemens Elmiskop IA.

scholarly journals Pigmentation of an Ostracod, Heterocypris Incongruens

1959 ◽  
Vol 36 (3) ◽  
pp. 575-582
Author(s):  
J. GREEN
Keyword(s):  
Green Algae ◽  
Green Alga ◽  
The Body ◽  
Blue Green Alga ◽  
Anaerobic Conditions ◽  
Blue Green Algae ◽  
Intermediate Metabolism ◽  
Different Types ◽  
Β Carotene ◽  
Heterocypris Incongruens

1. Heterocypris incongruens contains at least three different types of pigment: carotenoids, a pteridine, and a bilin. Haemoglobin and other haem pigments appear to be lacking in this species. 2. Astaxanthin and β-carotene are the only carotenoids found, even when the ostracod is feeding on algae containing abundant xanthophylls of various types. 3. A yellow pteridine, which rapidily decolorizes after extraction, is widespread in the body of the ostracod, but not in its eggs. It is suggested that this substance may play a part in the intermediate metabolism of the ostracod when in anaerobic conditions. Heterocypris can live and reproduce in anaerobic conditions for at least 2 weeks. 4. Biladiene pigments accumulate in the gut wall when the ostracod feeds on blue-green algae. These pigments can be made to disappear from the gut wall by restricting the diet to green algae, then made to reappear when a blue-green alga is given as food.

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