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.

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.

Creativity Thinks on the Significances of Geobiology about the Coal Series

2014 ◽  
Vol 1065-1069 ◽  
pp. 114-118
Author(s):  
Shuo Fu Tian ◽  
Chao Jin Lu ◽  
Yuan Wang
Keyword(s):  
Green Algae ◽  
Higher Plants ◽  
The Other ◽  
Coal Bed ◽  
Geologic History ◽  
Blue Green Algae ◽  
Living Things ◽  
Coal Petrology ◽  
The Relationship ◽  
Lower Plants

It is the components, living things evolution processes, development environments, distribution layers and the earliest time for coal series formation that are investigated and studied in detail based on the author’s graduation thesis, the “Geobiology” , the “China coal petrology” and the other’s some references in this paper. And it is considered that mainly two types of the Coal Series might be distinguish in the geologic history in China, respectively consisted of the lower organisms (especially the lower plants, blue-green algae) and higher organisms (especially the higher plants, pteridophyta, gymnosperms, Anthophyta). Meanwhile, the conclusions can be drawn that the development of the organisms is not only controlled by the environments, on the other hand, the environments and their sediments are also affected by the ecologies of the organisms. So the coal bed or coal series can be used as the marks of the environment explanation, perhaps having some Significances of Geobiology. In additional, the relationship with an unconformity or disconformity is discussed here, too.

Chromocentres and The Synaptinemal Complex

1970 ◽  
Vol 6 (3) ◽  
pp. 655-667
Author(s):  
L. F. LA COUR ◽  
B. WELLS
Keyword(s):  
Fine Structure ◽  
Electron Microscope ◽  
The Other ◽  
Near Surface ◽  
Thin Sections ◽  
Restricted Movement ◽  
Homologous Chromosomes ◽  
Synaptinemal Complex ◽  
Mother Cells ◽  
Fibrillar Network

The 1-4 chromocentres seen in nuclei of Fritillaria lanceolata, which derive from fusion of heterochromatic segments situated proximal to the centromere in all but two of the 24 chromosomes, were studied with the electron microscope in thin sections of pollen mother cells at zygotene and pachytene, in respect of the synaptinemal complex. Prophase stages of meiosis in two plants were also surveyed briefly with the light microscope. The latter observations revealed that the timing of the separation of heterochromatic segments from chromocentres is genetically controlled. In one plant the segments were still contained in chromocentres at pachytene, whereas in the other they were free at zygotene. At this time they could be identified by a near-surface position in the nucleus and an even condensation concomitant with an absence of chromomeres. In thin section, the fine structure of the chromocentres in zygotene nuclei was distinctive in that the chromatin fibrils were less condensed and more widely dispersed than those in euchromatic regions. The fibrillar network was also interspersed with ‘clear areas’ or channels. After further chromosome condensation, the condensation of fibrils in the chromocentres became equivalent at pachytene to those in euchromatic regions. Synaptinemal complexes were seen at zygotene and pachytene both in euchromatic regions and chromocentres. Their presence in the chromocentres signifies that homologous chromosomes must have been closely paired in regions extending from the centromeres to the distal ends of the heterochromatic segments already at telophase of the last pre-meiotic mitosis. Configurations involving entangled pairs of axial cores, peculiar to zygotene and chromocentres and parts of euchromatic regions proximal to them, are interpreted as resulting from restricted movement.

Reconstruction tridimensionnelle du chondriome de Ginkgo en culture tissulaire; étude au moyen de coupes épaisses et de coupes fines sériées

1979 ◽  
Vol 57 (4) ◽  
pp. 332-340 ◽  
Author(s):  
René Rohr
Keyword(s):  
Electron Microscope ◽  
Cultured Cells ◽  
Three Dimensional ◽  
The Other ◽  
Important Place ◽  
Thin Sections ◽  
Dimensional Models ◽  
Complete Cell ◽  
Three Dimensional Models

The observation of thick sections and serial thin sections with the electron microscope demonstrates a reticular organization of mitochondria in cultured cells from Ginkgo. Thick sections show that most of the mitochondria fuse either in loose networks made up of elongated elements or in dense clusters composed of globular units. Serial thin sections enable us to prove the true reticular nature of the mitochondrial organization; most of the mitochondrial profiles are part of highly fused and branched networks. These mitochondrial reticula (about two to three per cell) occupy an important place within the cell. Some mitochondria remain isolated or they fuse slightly. Two three-dimensional models have been built: the first one constructed with cardboard sheets is used to display the organization of a reticulum; the other of Plexiglas clearly indicates the relative positions and the form of mitochondria in a complete cell. The mitochondria, plastids, and vacuoles of this cell are also measured and enumerated.

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

scholarly journals AN ELECTRON MICROSCOPE STUDY OF THE EARLY ASSOCIATION BETWEEN TWO MAMMALIAN VIRUSES AND THEIR HOSTS

1962 ◽  
Vol 13 (2) ◽  
pp. 303-322 ◽  
Author(s):  
Samuel Dales
Keyword(s):  
Electron Microscope ◽  
Hela Cells ◽  
Electron Microscope Study ◽  
The Other ◽  
Single Particles ◽  
Thin Sections ◽  
Infectious Process ◽  
Free Particles ◽  
Whole Mount ◽  
Early Interaction

Early interaction between two animal viruses, vaccinia and adenovirus 7, which multiply readily in L strain and HeLa cells, respectively, was examined in both whole mount preparations and in thin sections. To observe the association at the surface, cells carrying adsorbed virus were swelled under controlled conditions and then "stained" with neutral phosphotungstate. Each particle of both virus types becomes attached to the cell by several capsomeres and is then ingested by phagocytosis. Within the cell, near the surface, single particles or small clumps of adenovirus are lodged within vesicles. Deeper in the cytoplasm this virus is packed in large, numerous inclusions, whereas very close to the nuclear envelope only free particles are found. Vaccinia, on the other hand, either free or in vesicles, is always found in the cytoplasm, at some distance from the nucleus (11). Adsorption and intracellular disposition of these two viruses is discussed in relation to the infectious process.

Blue–green algae and freshwater carbonate deposits

1978 ◽  
Vol 200 (1138) ◽  
pp. 43-61 ◽  
Keyword(s):  
Green Algae ◽  
Dry Mass ◽  
Liquid Media ◽  
Deposition Rates ◽  
Thin Sections ◽  
Blue Green Algae ◽  
Microcoleus Vaginatus ◽  
Small Crystals ◽  
Carbonate Deposits ◽  
Freshwater Carbonate

Twenty-seven contemporary freshwater carbonate deposits were investigated (26 in the British Isles and 1 in S. Australia). The blue–green algae Schizothrix calcicola and Microcoleus vaginatus occurred at 23 of the sites. The remaining sites represented areas where deposition had ceased. About 1% of the dry mass of the deposits consisted of Cyanophyta. The assimilation rates of these algae, measured by 14 CO 2 uptake, were low. It was estimated that the equilibrium change caused by CO 2 uptake due to photosynthesis could account for only 1–2% of the precipitated carbonate. Cultures of S. calcicola failed to deposit carbonates in solid and liquid media. Deposition rates varied between 0.006 and 8 mm a -1 (mean 1.2 mm a -1 ). The laminations encountered at some sites could be correlated to seasonal differences in cyanophyte growth which enabled some deposits to be dated. Thin sections revealed small crystals adhering to the muci­laginous sheaths of the algae. The transmission of light in some deposits was investigated. The algal layer corresponded to the depth to which light was attenuated to about 1% of the surface intensity.

scholarly journals Effect of Furadan on the Growth and Nitrogen Fixation by Blue Green Algae

1970 ◽  
Vol 15 ◽  
pp. 23-34
Author(s):  
MZ Islam ◽  
S Begum ◽  
H Ara ◽  
TM Waliullah
Keyword(s):  
Nitrogen Fixation ◽  
Green Algae ◽  
Calcareous Soil ◽  
Saline Soil ◽  
The Other ◽  
Soil Types ◽  
Heterotrophic Growth ◽  
Blue Green Algae ◽  
Unialgal Culture ◽  
Different Soils

The study was carried out to determine the effects of pesticide on the growth and nitrogen fixation by blue green algae (BGA) that isolated from three different soils of Bangladesh viz., saline soil, calcareous soil and red soil. Furadan 5G, one of the most commonly used pesticides was selected for the study of eighteen taxa of blue green algae (BGA) which brought under the unialgal culture in the selected soil types. Variations observed in growth and nitrogen fixation among the isolates of a particular type of soil. The culture resulted as BGA grow slow under heterotrophically grown cultures than that of autotrophically grown cultures. On the other hand, nitrogen fixation in heterotrophically grown cultures was observed at higher rate. However satisfactory result was observed in both cases when field dose of Furadan was applied practically. In this case, heterotrophically grown cultures were more tolerant to pesticides with respect to growth and nitrogen fixation. Key words: Blue green algae, Furadan, nitrogen fixation, heterotrophic growth, autotrophic growth.   doi: 10.3329/jbs.v15i0.2199 J. bio-sci. 15: 23-34, 2007

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.

scholarly journals OBSERVATIONS WITH THE ELECTRON MICROSCOPE ON THE FINE STRUCTURE OF THE NUCLEI OF TWO SPHERICAL BACTERIA

1961 ◽  
Vol 9 (1) ◽  
pp. 171-181 ◽  
Author(s):  
Woutera Van Iterson ◽  
C. F. Robinow
Keyword(s):  
Fine Structure ◽  
Electron Microscope ◽  
Electron Micrographs ◽  
Growth Cycle ◽  
The Other ◽  
Low Density ◽  
Thin Sections ◽  
Dna Molecule

The nuclei of two spherical bacteria have been examined in electron micrographs of thin sections of specimens prepared by the method of Ryter and Kellenberger (1958). The nuclei appear to consist of the same fine fibers in a matrix of low density which have already been seen in many other bacteria prepared by the same procedure. They are worth a separate description because their constituent fibers are arranged in patterns of uncommon orderliness. In the nuclei of one of the two bacteria this is seen at all times, in the nuclei of the other one only at the beginning of the growth cycle. In some places the diameter of the nuclear fibers is close to that of the DNA molecule in the model of Watson and Crick (1953).

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