The effects of Mg 2+, Ca 2+, Mn 2+, Co 2+ and Ni 2+ on the thermal stability of Salmon Sperm DNA were investigated by employing differential scanning calorimetry method. For the divalent cations, the shielding effect ...The effects of Mg 2+, Ca 2+, Mn 2+, Co 2+ and Ni 2+ on the thermal stability of Salmon Sperm DNA were investigated by employing differential scanning calorimetry method. For the divalent cations, the shielding effect plays the dominant role in the interaction of nucleic acid chains when they are in low concentrations, as reflected in the moderate increasing of DNA melting temperature. Along with increasing concentration, both alkaline earth metal ions and transitional metal ions were found to lower the DNA melting temperature, indicating possible direct interaction between the divalent cations with the bases in the DNA molecules. The effectiveness increases with the order Mg 2+, Ca 2+, Mn 2+, Co 2+ and Ni 2+. It was found for the first time that the presence of Mn 2+ triggered the biphasic-melting behavior of the Salmon Sperm DNA when the concentration of the cation was increased to a value about 2 times of phosphorous in DNA.展开更多
Ultrastructual characteristics of Sertoli cells of Salmonidae from Ohrid Lake during the spermatogenetic cycle have been analysed. Sertoli cells being an integral part of the seminiferous lobules underwent considerabl...Ultrastructual characteristics of Sertoli cells of Salmonidae from Ohrid Lake during the spermatogenetic cycle have been analysed. Sertoli cells being an integral part of the seminiferous lobules underwent considerable changes, which influenced their cytomorphological features. The degenerative changes of Sertoli cells were manifested by an extreme vacuolisation, mitochondria in degeneration with widened crysts and thickened matrix, desorganised ER, autophagosomes, ＂myeline-like＂ structures and lysed cytoplasmic regions. The above mentioned changes were followed by karyopycnisis, comlete degeneration and delamination of cells from the wall of the seminiferous lobules, lysis and detritus formations （Sertoli necrotic material） in the lumen of the lobules. The aim of this paper is special research of the ultrastructural characteristics, i.e. the changes on a level with testes which happen in the postspawning period in the two species of Teleostei of Ohrid Lake, Ohrid trout （Salmo letnica Kar.） and Ohrid belvica （Acantholingua ochridana Steind.）. The postspawning period is emphasized in Teleostei in this relatively short period, when one reproductive cycle finishes and the following has to start, on a level of testicular parenhyma very important histological changes are going on which give special histological identification, i. e. in the postspawning period there is a complete reorganization of the testes.展开更多
文摘The effects of Mg 2+, Ca 2+, Mn 2+, Co 2+ and Ni 2+ on the thermal stability of Salmon Sperm DNA were investigated by employing differential scanning calorimetry method. For the divalent cations, the shielding effect plays the dominant role in the interaction of nucleic acid chains when they are in low concentrations, as reflected in the moderate increasing of DNA melting temperature. Along with increasing concentration, both alkaline earth metal ions and transitional metal ions were found to lower the DNA melting temperature, indicating possible direct interaction between the divalent cations with the bases in the DNA molecules. The effectiveness increases with the order Mg 2+, Ca 2+, Mn 2+, Co 2+ and Ni 2+. It was found for the first time that the presence of Mn 2+ triggered the biphasic-melting behavior of the Salmon Sperm DNA when the concentration of the cation was increased to a value about 2 times of phosphorous in DNA.
文摘Ultrastructual characteristics of Sertoli cells of Salmonidae from Ohrid Lake during the spermatogenetic cycle have been analysed. Sertoli cells being an integral part of the seminiferous lobules underwent considerable changes, which influenced their cytomorphological features. The degenerative changes of Sertoli cells were manifested by an extreme vacuolisation, mitochondria in degeneration with widened crysts and thickened matrix, desorganised ER, autophagosomes, ＂myeline-like＂ structures and lysed cytoplasmic regions. The above mentioned changes were followed by karyopycnisis, comlete degeneration and delamination of cells from the wall of the seminiferous lobules, lysis and detritus formations （Sertoli necrotic material） in the lumen of the lobules. The aim of this paper is special research of the ultrastructural characteristics, i.e. the changes on a level with testes which happen in the postspawning period in the two species of Teleostei of Ohrid Lake, Ohrid trout （Salmo letnica Kar.） and Ohrid belvica （Acantholingua ochridana Steind.）. The postspawning period is emphasized in Teleostei in this relatively short period, when one reproductive cycle finishes and the following has to start, on a level of testicular parenhyma very important histological changes are going on which give special histological identification, i. e. in the postspawning period there is a complete reorganization of the testes.
