scholarly journals Cyanophytes on limestone rocks in the Szopczański Gorge (Pieniny Mountains) – their ecomorphology and ultrastructure

2011 ◽  
Vol 80 (3) ◽  
pp. 205-209 ◽  
Author(s):  
Joanna Czerwik-Marcinkowska ◽  
Bohuslav Uher

This study is devoted to the ecomorphology and ultrastructure of cyanophytes on limestone rocks collected in the Szopczański Gorge (Pieniny Mountains) during the years 2006-2008. There were selected cyanophyte species for examination such as following: <em>Nostoc microscopicum</em>, <em>Phormidium favosum</em>, <em>Leptolyngbya foveolarum</em>, <em>Tolypothrix distorta </em>var. <em>penicillatum</em>, <em>Pseudanabaena catenata</em>. The ultrastructural analysis (TEM) confirmed that the structure and placement of the thylakoids is genus/species specific.

Author(s):  
Beata Messyasz ◽  
Joanna Czerwik-Marcinkowska ◽  
Bohuslav Uher ◽  
Andrzej Rybak ◽  
Lidia Szendzina ◽  
...  

AbstractUlva flexuosa subsp. pilifera previously known from northern Poland, from the channel near Szczecin and ponds near Łódź, has recently been found in the Malta Reservoir in the Wielkopolska (West Poland) region. Specimens collected in the Wielkopolska region were examined in detail, also under a transmission electron microscope (TEM). The morphometric analysis of Ulva thalli (both young and mature specimens) was performed in order to study the differences in the ultrastructure of vegetative cells. Rectangular cells in young thalli measured from 32.21–55.81 μm to 20.24–35.12 μm, and they formed clear longitudinal rows, while cells in the mature specimens ranged from 25.09–47.66 μm to 18.90–31.56 μm. This study indicates that vegetative cells of the mature thalli show tendency towards distortions of both the longitudinal and transverse cells arrangement. This distortion is determined by the development of possible carbonate calcium crystals on the thalli surface. The ultrastructural analysis (TEM) confirmed that the structure and placement of thylakoids is genus/species specific.


Author(s):  
I. Brent Heath

Detailed ultrastructural analysis of fungal mitotic systems and cytoplasmic microtubules might be expected to contribute to a number of areas of general interest in addition to the direct application to the organisms of study. These areas include possibly fundamental general mechanisms of mitosis; evolution of mitosis; phylogeny of organisms; mechanisms of organelle motility and positioning; characterization of cellular aspects of microtubule properties and polymerization control features. This communication is intended to outline our current research results relating to selected parts of the above questions.Mitosis in the oomycetes Saprolegnia and Thraustotheca has been described previously. These papers described simple kinetochores and showed that the kineto- chores could probably be used as markers for the poorly defined chromosomes. Kineto- chore counts from serially sectioned prophase mitotic nuclei show that kinetochore replication precedes centriole replication to yield a single hemispherical array containing approximately the 4 n number of kinetochore microtubules diverging from the centriole associated "pocket" region of the nuclear envelope (Fig. 1).


Author(s):  
Linda Sicko-Goad

Although the use of electron microscopy and its varied methodologies is not usually associated with ecological studies, the types of species specific information that can be generated by these techniques are often quite useful in predicting long-term ecosystem effects. The utility of these techniques is especially apparent when one considers both the size range of particles found in the aquatic environment and the complexity of the phytoplankton assemblages.The size range and character of organisms found in the aquatic environment are dependent upon a variety of physical parameters that include sampling depth, location, and time of year. In the winter months, all the Laurentian Great Lakes are uniformly mixed and homothermous in the range of 1.1 to 1.7°C. During this time phytoplankton productivity is quite low.


Author(s):  
Gerald Rupp

The marine protozoan Allogromia sp, strain NF Lee extends an elaborate reticulopodial network (RN) which contains an elongate microtubule-(MT)-based cytoskeleton. The MTs are located primarily within cytoplasmic fibrils which are visible by light microscopy (LM) in highly flattened or “two dimensionalized” reticulopodia. It was shown previously that allogromiid RNs withdraw in response to hypertonic Mg2+-seawater. An ultrastructural analysis of this phenomenon indicated that large patches of paracrystalline (PC) material, composed of helical filament aggregates, form concomitant with a decrease in MT number. Similar large patches of PC aggregates are also found in juvenile Allogromia before they extend a RN, which disappear during RN formation. Finally, PC aggregates are occasionally seen near microtubules in normal untreated RNs. Thus there is circumstantial evidence to propose that PC aggregates in Allogromia represent an intermediate form of tubulin; however, more definitive biochemical or immunocytochemical data is not available.


2005 ◽  
Vol 173 (4S) ◽  
pp. 18-18
Author(s):  
Joseph C. Liao ◽  
Mitra Mastali ◽  
David A. Haake ◽  
Bernard M. Churchill

1960 ◽  
Vol 15 (10) ◽  
pp. 665-665
Author(s):  
George S. Grosser
Keyword(s):  

1996 ◽  
Vol 76 (06) ◽  
pp. 1090-1095 ◽  
Author(s):  
C Ravanat ◽  
M Freund ◽  
S Schuhler ◽  
P Grunert ◽  
L Meyer ◽  
...  

SummaryThe purpose of this study was to develop specific and sensitive immunoassays to detect early indices of hypercoagulability in the rat. Rat platelet factor 4 (rPF4) and rat fibrinopeptide A (rFPA) assays, tools for the detection of activation of platelets and coagulation respectively, were designed using antibodies raised against purified rPF4 and against synthetic rFPA. The relevance of these new assays and of the commercially available ELISA kit for thrombin-antithrombin III (TAT) complexes was demonstrated in a rat model of a prethrombotic state induced by intravenous infusion of varying doses of thromboplastin (90 to 2400 μl/kg/h). In this model, the immunoassays allowed simultaneous detection of low levels of rFPA and rPF4 which were correlated with fibrinogen and platelet consumption and TAT generation and further proved to be of higher sensitivity than the classical methods of platelet count or measurement of fibrinogen levels. Plasma concentrations of rFPA, rPF4 and TAT were dependent on infusion time and thromboplastin dose, while hirudin (1 mg/kg) prevented their appearance. Thus the new specific immunoassays for rPF4 and rFPA and the commercial human TAT assay represent useful tools for pathophysiological studies or the screening of antithrombotic drugs in rats.


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