The effect of UV-C radiation on thylakoid arrangement, chlorophyll-a and carotenoid content and nitrogenase activity of the cyanobacterium Microchaete sp. was studied. Chlorophyll-a and carotenoid content increased gradually up to 48 h of UV-C exposure but declined with longer exposures. Nitrogenase activity decreased moderately with 6 to 12 h exposure and decreased substantially afterwards. When cells exposed to UV-C for 12 to 24 h, grown under fluorescent light for 144 h, nitrogenase activity increased to levels greater than in the control cells. The exposure of UV-C treated cells to fluorescent light, however, did not result in recovery of pigment content. In Microchaete sp. cells treated with UV-C for 144 h, thylakoid membranes became dense, were aggregated into bundles, and were surrounded by spaces devoid of cytoplasm.

• MeSH
• biologické pigmenty metabolismus   MeSH
• nitrogenasa metabolismus   MeSH
• sinice enzymologie   metabolismus   účinky záření   MeSH
• transmisní elektronová mikroskopie MeSH
• tylakoidy metabolismus   MeSH
• ultrafialové záření * MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• biologické pigmenty MeSH
• nitrogenasa MeSH

Follicular development is characterized by intensive proliferation and differentiation of granulosa cells. It was reported that during follicular growth granulosa cells arise from the population of stem cells. One of the main evidences for stem characteristics of the cell is the ability to express telomerase--an enzyme complex responsible for integrity and stability of chromosome ends (telomeres). It was demonstrated that telomerase activity in granulosa cells is linked to their proliferation and differentiation status and is under the control of growth factors and steroid hormones. In this review current knowledge on the existence and regulation of telomerase activity in granulosa cells has been presented.

• MeSH
• buněčná diferenciace * MeSH
• estradiol metabolismus   MeSH
• folikulární buňky enzymologie   MeSH
• lidé MeSH
• ovariální folikul cytologie   enzymologie   MeSH
• proliferace buněk MeSH
• regulace genové exprese genetika   MeSH
• telomerasa * genetika   metabolismus   MeSH
• telomery * enzymologie   MeSH
• Check Tag
• lidé MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• přehledy MeSH
• Názvy látek
• estradiol MeSH
• telomerasa * MeSH
• TERT protein, human MeSH Prohlížeč

Hypothesis of coherent vibration states in biological systems based on nonlinear interaction between longitudinal elastic and electric polarization fields with metabolic energy supply was formulated by Frohlich. Conditions for excitation of coherent states and generation of electromagnetic fields are satisfied in microtubules which form electrical polar structures. Numerical models are used for analysis of Frohlich's vibration states in cells. Reduction of activity and of energy production in mitochondria, and disintegration of cytoskeleton structures by phosphorylation on the pathway of cancer trasformation can diminish excitation of the Frohlich's vibration states and of the generated electromagnetic field, which results in disturbances of the interaction forces between cells. Interaction forces between cancer cells may be smaller than interaction forces between healthy cells and cancer cells as follows from numerical models. Mechanism of malignity, i.e. local invasion, detachment of cancer cells, and metastasis, is assumed to depend on the electromagnetic field.

• MeSH
• biofyzika metody   MeSH
• biologické modely MeSH
• buňky 3T3 MeSH
• cytoskelet metabolismus   MeSH
• elektromagnetická pole MeSH
• elektromagnetické jevy * MeSH
• lidé MeSH
• mikroskopie atomárních sil MeSH
• mikrotubuly metabolismus   MeSH
• mitochondrie metabolismus   MeSH
• myši MeSH
• nádory metabolismus   MeSH
• pružnost MeSH
• Saccharomyces cerevisiae metabolismus   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH