Size Fractionation and Characterisation of Fresh Water Colloids and Particles:  Split-Flow Thin-Cell and Electron Microscopy Analyses

2006 ◽  
Vol 40 (21) ◽  
pp. 6738-6743 ◽  
Author(s):  
Anna De Momi ◽  
Jamie. R. Lead
Keyword(s):  
Electron Microscopy ◽  
Fresh Water ◽  
Size Fractionation ◽  
Split Flow

Electron Microscope Observations on DNA and Chromatin Fibres of Hydra Vulgaris and Ephydatia Meyeni

1972 ◽  
Vol 30 ◽  
pp. 198-199
Author(s):  
Anjali Mookerjee
Keyword(s):  
Electron Microscopy ◽  
Electron Microscope ◽  
Fresh Water ◽  
Cell Lysis ◽  
Laboratory Culture ◽  
Hydra Vulgaris ◽  
Chromatin Material ◽  
Protein Monolayer

The present paper reports the observations made on DNA and chromatin material obtained from Hydra vulgaris (raised in laboratory culture) and a fresh water sponge Ephydatia meyeni. Both samples were prepared following Marmur's method, with slight modifications. For the chromatin fibres, samples were used just after the cell lysis stage without any shaking or further purification procedures. The specimens for electron microscopy were prepared by the protein monolayer technique.The diameter of rotary shadowed purified DNA samples from H. vulgaris and E. meyeni was 60-80 A and the length of the Fibres varied between 5-18 /u (Fig. 1), and 5-10/u respectively.

The ultrastructure and taxonomy of Diacronema vlkianum (Prymnesiophyceae) with special reference to the haptonema and flagellar apparatus

1977 ◽  
Vol 57 (4) ◽  
pp. 1125-1136 ◽  
Author(s):  
J. C. Green ◽  
D. J. Hibberd
Keyword(s):  
Electron Microscopy ◽  
Light Microscopy ◽  
Special Reference ◽  
Optical Microscopy ◽  
Fresh Water ◽  
Flagellar Apparatus ◽  
Taxonomic Position ◽  
New Family ◽  
Shadow Cast ◽  
Living Material

The taxonomic position of the golden-brown flagellate Diacronema vlkianum Prauser has hitherto been uncertain. It was first reported by Vlk (1938) from fresh water and a brief description given, particular interest being ascribed to the flagella which staining and light microscopy indicated to be without appendages. Because of this Vlk concluded that the organism, which he did not name, occupied a taxonomic niche somewhat apart from typical chrysophytes. In 1958, Prauser isolated, also from fresh water, a flagellate which he identified as Vlk's organism and he described it using both electron microscopy of shadow-cast cells and optical microscopy of living material. He confirmed the lack of flagellar hairs and discussed the taxonomy of Diacronema in relation to both the Ochromonadales with heterokont flagella and the genus Chrysochromulina Lackey with equal smooth flagella. He suggested that the genus could be thought of as representing a new family, the Diacronemataceae, arising from an ochromonad stock and possibly representing a unique line within the chrysomonads.

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