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.

Membrane-bound vesicles associated with the microvilli in the midgut of the freshwater microcrustacean, Daphnia magna

1983 ◽  
Vol 41 ◽  
pp. 480-481
Author(s):  
Patricia L. Jansma
Keyword(s):  
Daphnia Magna ◽  
Intestinal Epithelial Cells ◽  
Uranyl Acetate ◽  
Intestinal Epithelial ◽  
Chlamydomonas Reinhardii ◽  
Thin Sections ◽  
Saturated Water ◽  
Cacodylate Buffer ◽  
Membrane Bound ◽  
Ethanol Series

The presence of the membrane bound vesicles or blebs on the intestinal epithelial cells has been demonstrated in a variety of vertebrates such as chicks, piglets, hamsters, and humans. The only invertebrates shown to have these microvillar blebs are two species of f1ies. While investigating the digestive processes of the freshwater microcrustacean, Daphnia magna, the presence of these microvillar blebs was noticed.Daphnia magna fed in a suspension of axenically grown green alga, Chlamydomonas reinhardii for one hour were narcotized with CO2 saturated water. The intestinal tracts were excised in 2% glutaraldehyde in 0.2 M cacodyl ate buffer and then placed in fresh 2% glutaraldehyde for one hour. After rinsing in 0.1 M cacodylate buffer, the sample was postfixed in 2% OsO4, dehydrated with a graded ethanol series, infiltrated and embedded with Epon-Araldite. Thin sections were stained with uranyl acetate and Reynolds lead citrate before viewing with the Philips EM 200.

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.

Gap junction associated filaments in testis interstitial cells of the rat

1978 ◽  
Vol 36 (2) ◽  
pp. 550-551
Author(s):  
J.F. David-Ferreira ◽  
K.L. David-Ferreira ◽  
M.H. Miranda ◽  
J.C. Lemos
Keyword(s):  
Gap Junction ◽  
Freeze Fracture ◽  
Interstitial Cells ◽  
Uranyl Acetate ◽  
Lead Citrate ◽  
Thin Sections ◽  
Cacodylate Buffer ◽  
Old Rats ◽  
The Relationship ◽  
Made In

The testis interstitial cells of the rat are closely associated forming small aggregates in the vicinity of the vessels. The finality of the present study is to analise the relationship between the interstitial cells and to describe some particularities of their junctions.The observations were made in thin sections from testis of 2 to 3 months old rats fixed by immersion or perfusion with 2 to 3% glutaral- dehyde in s-collidine or cacodylate buffer followed by 2% osmium tetro-xyde in the same buffers. Some specimens have been prepared following the technique of Shea. The thin sections obtained after embedding in Epon were double stained in uranyl acetate and lead citrate. For the cryofracture study the tissues were fixed in 3% glutaraldehyde in cacodylate buffer, impregnated in 28% glycerol, frozen in Freon 22 and stored in liquid nitrogen. Freeze fracture and platinum-carbon shadowing were done in a Balzers 300.

Ultrastructure of E. coli: An in vitro study of cells cultured in the presence of four gastrointestinal (GI) hormones

1990 ◽  
Vol 48 (3) ◽  
pp. 628-629
Author(s):  
Leo J. Henz ◽  
Frank E. Johnson
Keyword(s):  
Morphological Changes ◽  
In Vitro Study ◽  
Uranyl Acetate ◽  
Culture Collection ◽  
En Bloc ◽  
Thin Sections ◽  
E Coli ◽  
Cacodylate Buffer ◽  
Synthetic Hormones

Hormones are found in exocrine secretions entering the gut. They alter the morphology of many eukaryotic cells; whether they affect the morphology of enteric flora is unknown. In this study, we examined the ultrastructure of E. coli, a common bacterium in the mammalian gut, for morphological changes resulting from exposure to GI hormones.E. coli (#11775 from American Type Culture Collection) were grown in protease-free trypticase soy broth (TSB) at 37°C for 18 hr to a concentration of 2 x 107 cells/ml. Pure synthetic hormones were used: sulfated C-terminal cholecystokinin octapeptide (CCK), pentagastrin (PG), cyclic somatostatin tetradecapeptide (SS), or the porcine form of secretin (SEC). These were individually added to. bacterial cultures in TSB to make 1 x 107 organisms/ml and 0.0, 0.5, 2.5, or 5.0 μg of hormone/ml, then incubated for 30 min at 37°C. The cultures were rapidly chilled and added to equal volumes of cold 6% glutaraldehyde in 0.2 M cacodylate buffer. After 30 min, the bacteria were concentrated by centrifugation (15 min at 4000 RPM) and the pellets suspended in cold 3% glutaraldehyde for an additional 15 min, followed by centrifugation. The pellets were resuspended in cold cacodylate buffer and stored at 2°C for 1-7 d. The cells were again centrifuged and the pellets were blotted with a strip of filter paper to remove excess fluid, then mixed with a drop of warm 2% agar. The agar suspensions were pipetted into cold saline. The resulting solidified extrusions were cut by hand into 2 mm segments for further processing in 1% OsO4 (with or without en bloc staining in 2% uranyl acetate (UA) in ethanol). Following dehydration in ethanol, rinsing in propylene oxide, and encapsulation in Epon-Araldite, thin sections were examined and photographed with a JEOL-100C microscope.

Ultrastructural Characteristics of Vaginal Epithelium of Persistent Estrous Rats

1985 ◽  
Vol 43 ◽  
pp. 658-659
Author(s):  
Khosho Francis K. ◽  
Kaufmann Robert C. ◽  
Amankwah Kofi S.
Keyword(s):  
Osmium Tetroxide ◽  
Uranyl Acetate ◽  
Ruthenium Red ◽  
Female Rats ◽  
Constant Light ◽  
Ultrastructural Changes ◽  
Vaginal Smears ◽  
Thin Sections ◽  
Cacodylate Buffer ◽  
Ultrastructural Characteristics

Adult female rats exposed to constant light will develop anovulatory acyclicity characterized by persistent vaginal cornification (PE) and formation of multiple large cystic follicles on the ovaries. The purpose of the present communication is to describe the ultrastructural changes in vaginal epithelia in PE rats as compared to that in normal estrous rats.Persistent vaginal estrous with PCO was induced in a group of Sprague-Dawely rats by exposure to constant light for 50-150 days. Rats in normal estrous, as determined by vaginal smears, were used as controls. Nembutal- anethesized rats were perfused through the aorta with 2.5% gluteraldehyde in 1M sodium cacodylate buffer (pH 7.3). The mucosa of the vaginal folds just inferior to the cervix were dissected by microsurgery, postfixed, stained with 0.5% ruthenium red in 1% osmium tetroxide, dehydrated, and embedded in polybed. Thick sections (1μ) were stained with toludine blue for light microscopy studies. Thin sections were stained with uranyl acetate and lead citrate.

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.

Ultrastructural Study of Trophozoites and Cysts of Acanthamoeba-Hartmannella and Naegleria Species

1974 ◽  
Vol 32 ◽  
pp. 192-193
Author(s):  
A. Julio Martinez ◽  
Richard J. Duma ◽  
Doris G. Fultz ◽  
Ruth B. Finley
Keyword(s):  
Present Report ◽  
Uranyl Acetate ◽  
Osmic Acid ◽  
Acetate Solution ◽  
Lead Citrate ◽  
Thin Sections ◽  
Cacodylate Buffer ◽  
In Situ Fixation ◽  
Diamond Knife

Ultrastructural components of trophozoites and cysts of Acanthamoeba-Hartmannella (A-H) and Naegleria amebas have been investigated. The present report describes a technique to study the morphological features of such protozoa.The A-H strains selected were cultured for 7 days in axenic amebic media, and the Naegleria strains were cultured for 7 days in axenic media with blood. In situ fixation was accomplished by adding an equal volume of 4% Osmic Acid in Cacodylate buffer at 4¶C for one hour. Following frequent agitation, the tubes were then spun at 2500 RPM for 10 minutes to obtain a pellet. The pellets were dehydrated in graded series of alcohols (from 50% to absolute) and propylene oxide and then embedded in EPON. One micron sections were stained with Paragon (PS 1301) for thirty seconds. Thin sections were cut with a diamond knife, double stained with 5% alcoholic uranyl acetate solution and lead citrate and observed in an Hitachi-HS-8F2 electron microscope.

The Role of the Internal Coating in the Ultrastructural Architecture of Pinocytic Vesicles and its Significance in Vesicular Transport

1971 ◽  
Vol 29 ◽  
pp. 398-399
Author(s):  
T. Shirahama ◽  
A. S. Cohen ◽  
O. G. Rodgers
Keyword(s):  
Body Weight ◽  
Uranyl Acetate ◽  
Ruthenium Red ◽  
Lead Citrate ◽  
Healthy Young Adult ◽  
Thin Sections ◽  
Cacodylate Buffer ◽  
New Zealand White Rabbits ◽  
Pinocytic Vesicles

Forty-micron nonfrozen sections of myocardium from several healthy young adult New Zealand white rabbits, without pretreatment or 10-15 minutes after an intravenous ferritin injection (100 mg ferritin/100 gm. body weight), were double fixed with 2% formaldehyde - 2.5% glutaraldehyde in 0.1M cacodylate buffer and 2% OSO4 in 0.1M cacodylate buffer in the presence of 1000, 100, 50 or 20 ppm ruthenium red (RR), and embedded in Epon. Thin sections of small blood vessels including capillaries, unstained or stained with uranyl acetate and/or lead citrate, were photographed at initial magnifications of 40,000 or 80,000. The results were analysed to delineate the ultrastructural relation of mucopolysaccharides (MPS) in the architecture of pinocytic vesicles and the MPS role in pinocytosis.

Redistribution of Membranes during Conidiogeneses and Nuclear Development in Verticillium Dahliae

1977 ◽  
Vol 35 ◽  
pp. 344-345
Author(s):  
J. E. Mayfield ◽  
W. J. Tolmsoff ◽  
M. H. Wheeler
Keyword(s):  
Present Report ◽  
Nuclear Material ◽  
Uranyl Acetate ◽  
Thin Sections ◽  
Cacodylate Buffer ◽  
Primary Means ◽  
Nuclear Development ◽  
Single Nucleus ◽  
Conidial Formation ◽  
And Migration

Verticil1ium dahliae is an asexual fungus that produces unicellular, mononucleate conidia as its primary means of reproduction. For conidial formation, specialized hyphal cells convert into verticillate conidiophores, bearing tapered phialides. A conidium develops from the phialide as a protrusion through the terminal pore. Each phialide has a single nucleus that divides repeatedly during the sequential production of numerous conidia. Nuclear material has been found to migrate into developing conidia just before their separation from the phialide tip (1). The present report suggests a possible mechanism for nuclear division and migration.The ultrastructure of phialides and developing conidia of V. dahliae was examined from a narrow zone 5 mm behind the periphery of colonies grown on potato-carrot-dextrose agar. Cells were fixed with 3l glutaraldehyde in cacodylate buffer (pH 6.8) at room temperature, postfixed in cold 2% OsO4 in the same buffer, and thin sections were counter stained with 2% uranyl acetate and lead citrate.

Ultrastructural Observations on Microspore Development in Rice Anther Culture

1985 ◽  
Vol 43 ◽  
pp. 646-647
Author(s):  
S. S. Ren ◽  
J. C. Chen ◽  
Y. R. Chen
Keyword(s):  
Anther Culture ◽  
Oryza Sativa L ◽  
Uranyl Acetate ◽  
Lead Citrate ◽  
Microspore Development ◽  
Thin Sections ◽  
Cacodylate Buffer ◽  
Fine Structures ◽  
Development In Vitro

The plants produced from rice anther culture varied in ploidy level. Genetic analysis of anther-derived plants indicated genome multiplication occurred in microspore development in vitro. Cytological studies on early roicrospore division suggested endoreduplication and nuclear fusion may be related to the production of nonhaploid plants. In the present study, fine structures of callus ontogeny in anther culture were emphasized.Anthers of rice(Oryza sativa L. c. v. Hsinchu 4, 2n=24) containing mid-uninucleate microspores were excised and cultured in Ng liquid medium, supplimented with 60 g/l sucrose, 1 mg/l kinetin and 2 mg/l naphthalenacetic acid. Cultured anthers were collected at 2 days intervals for 20 days and fixed in 2.5% glutaraldehyde in 0.1M cacodylate buffer(pH=7.0), postfixed in osmium tetraoxide, and then embedded in Spurr's resin. Thin sections were stained with uranyl acetate and lead citrate, observed under Hitachi H-600 at 75 KV.

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