ABSTRACT
Microtubules [MT] are important components of cell cytoskeleton and play key roles in cell motility mitosis and meiosis. They are also the targets of several anticancer agents which indicating their importance in maintaining cell viability. Microtubular reorganization contributing to apoptotic morphology occurs in normal and neoplastic cells undergoing apoptosis induced by cytotoxic drugs. The aim of this study was to correlate the changes in the MT with behavior of the gamma-tubulin in apoptotic cell, and to see if apoptitic MT showed biochemical characteristics of stable MT. Apoptosis was induced in the human leukemia cells [HL-60] by treatment with 1 microM of all-trans retinoic acid over a 5-day period. The time course of changes was assessed using flow cytometry, DNA fragmentation and immunocytochemistry in cells labeled for alpha-tubulins, acetylated alpha-tubulin and gamma-tubulin. The results indicated that gamma-tubulin content is increased after cells have gone through the apoptosis with a diffuse cytoplasmic pattern. alpha-tubulin did not reveal any specific pattern of polymerization in apoptotic cells and acetylated alpha-tubulin content was also decreased in comparison with non-apoptotic cells. Our results support the idea that microtubule reorganization is an important factor of the mammalian cells response to apoptosis, and the altered properties of the MT did not reflect changes in function as apoptosis progresses
ABSTRACT
The efficacious effects of pulsed electromagnetic field [PEMF] under the certain field parameters like frequency and the field intensity have been reported for various tissue and molecules. Since collagen is found abundantly in most tissue structures, this research was designed to further investigate the effects of extremely low frequency [ELF] PEMF on the synthesis of the epidermal collagen. To do the task, six groups of animals each consisting of eight mature male rats were selected randomly as one group for the control and five for the test. The field was generated by using a parallel set of Helmholtz coil. The first set of experiments was carried out at the peak intensity of 2 mT [milli Tesla] for different frequencies of 25, 50 and 100 Hz. Since the most effective frequency turned out to be 25 Hz, another set of experiment was conducted using this frequency and two different field intensities of 1 and 4 mT. The field was applied for 2.5 h/day lasting for 8 days, keeping the same procedure for the control group except for the field turned off. On the ninth day, the rats were sacrificed and the skin samples from the dorsal region were taken for biochemical assessment of collagen by measuring hydroxyproline content using Stegeman-Stalder method and histological assessment. The data indicated that pulsed electromagnetic field of 2 mT at 25 Hz increased the collagen synthesis [P<0.05]. The other intensities and frequency setting did not have much distinguishable effect, however, at the frequency of 25 Hz and 4 mT, the field effect on the collagen increase was also noticeable. It was concluded that applying the field parameters of 25 Hz and 2 mT peak intensity for 2.5 h/day during eight days rendered a significant increase in collagen synthesis in rat skin. Histological observations were consistent with the biochemical findings
Subject(s)
Animals, Laboratory , Collagen/biosynthesis , Skin , RatsABSTRACT
Rotavirus, a triple-layered non-enveloped member of the Reoviridae family, obtained a transient membrane envelope when newly synthesized subviral particles bud into the endoplasmic reticulum [ER]. As rotavirus particles mature, they lose their transient membrane and obtain outer layer. It is mostly believed that only double layered particles bud into the ER. The present study describes that the single layered particles can also bud into the ER and become the immediate precursors of the mature virions. Virus replication was studied within a line of African green monkey kidney [BSC-1] cells infected with simian rotavirus SA11. The virus intermediate capsid protein [VP6] was localized within the infected cells using protein A-gold. Monospecific antibody to VP6 was the primary antibody. The electron micrographs of budding sites of ER showed two different sizes of subviral particles. The gold particles were seen on the double layered particles and very little in the cytoplasm and some on ER or very close to it. These results indicate that the single layered particles are also capable of being the precursor of the triple layered and obtain the VP6 while budding into the ER