RESUMO
Motility is the most important property of mammalian sperm required for fertilization. Axoneme and axoneme surrounding tail components are the morphological substrate of sperm motility. Quantitative research methods of human spermatozoa motility allowed the definition of the normative parameters for fertile men. Exogenous factors, and, rarely, genetic defects may cause a significant reduction in sperm motility. Axonemal anomalies (absence of external and/or internal dynein arms, central pair of microtubules absence) may be the cause of primary ciliary dyskinesia (PCD). PCDa severe systemic disease of the reduction of sperm motilityis just one symptom. Dysplasia of the fibrous sheath (DFO) is also genetically determined sperm motility decrease. PCD and the DFO are multigene diseases that are inherited in an autosomal recessive manner. Modern molecular biological research methods are used to identify candidate genes. Assisted reproduction technologies (ART) allow men suffering from PCD and DFO to produce offspring. PCD and DFO symptoms appear in the homozygote. Children born after ART have the probability of being mutation carriers. We do not have complete information about etiological factor of genetically determined spermpathology. So we cannot assess the genetic risk degree. However, the possibility of mutations accumulation, which can be a risk factor for distant offspring, should be considered.
Assuntos
Microtúbulos , Motilidade dos Espermatozoides/genética , Cauda do Espermatozoide , Humanos , Masculino , Microtúbulos/genética , Microtúbulos/metabolismo , Microtúbulos/ultraestrutura , Cauda do Espermatozoide/metabolismo , Cauda do Espermatozoide/ultraestruturaRESUMO
Various complexes of phagocytes with adsorbed (I) and entrapped (J) particles are formed during phagocytosis. Method of stereological reconstruction is proposed that allows to demonstrate the actual distribution of these complexes on the basis of morphometric analysis of their ultrathin sections. The principle of the method lies on the probability simulation of section distribution for a given distribution of complexes and on the solution of the reverse problem by stepwise determination of the relative quantity of each complex type (from the most complicated to the most simple one, when I = 0 and J = 0). The stereological analysis of phagocytosing murine peritoneal macrophages revealed an absolutely different and more adequate kinetical picture of phagocytosis, as compared to the morphometric data.
Assuntos
Fagocitose , Absorção , Adsorção , Animais , Candida albicans , Cinética , Macrófagos/imunologia , Macrófagos/ultraestrutura , Matemática , Camundongos , Camundongos Endogâmicos CBA , Modelos Biológicos , Fatores de TempoRESUMO
An increase of contact interaction between macrophages and thymocytes in the presence of polysaccharide chitosan was suggested to be due to the change of surface charge of interacting cells. It was found that incubation of thymocytes in the presence of chitosan leads to the change of their charge in the positive direction. The measurement of electrophoretic mobility of the cells was carried out on " Parmoquant 2" (Carl Zeiss Jena, DDR). The change of electrophoretic mobility increases with decrease of pH, increase of chitosan concentration and decrease of the cell concentration in the medium. This phenomenon is probably due to absorption of positively charged molecules of chitosan on negatively charged cell surface.
Assuntos
Quitina/análogos & derivados , Timo/citologia , Animais , Movimento Celular/efeitos dos fármacos , Quitina/farmacologia , Quitosana , Relação Dose-Resposta a Droga , Eletroforese , Concentração de Íons de Hidrogênio , Técnicas In Vitro , Camundongos , Camundongos Endogâmicos CBARESUMO
Using flow cytofluorimetry, acidification in macrophages was studied during phagocytosis of yeast cells Candida albicans conjugated with FITC. Two phases of acidification were found: one corresponding presumably to yeast cell absorption on the macrophage surface, and the other one being due to cell incorporation into phagolysosomes. The phases are characterized by pH values of 6.3 +/- 0.5 and 4.5 +/- 0.5, respectively. Addition of 10 mM NH4Cl cancelled the observed acidification, whereas the presence of cytochalasin B (2 . 10(-5) M) prevented the very process of acidification.
Assuntos
Macrófagos/metabolismo , Organoides/metabolismo , Fagocitose , Animais , Líquido Ascítico/citologia , Candida albicans , Citometria de Fluxo , Concentração de Íons de Hidrogênio , Cinética , Camundongos , Camundongos Endogâmicos CBARESUMO
Optimal conditions are developed for two methods of simultaneous recording of 45Ca and 32P-radiation in the bone and other tissues. Both methods are compared from the standpoint of their efficiency. The calculation method for the 32P hard beta-radiation in the presence of 45Ca in one tissue specimen by the liquid scintillation counter is 5-10 times as efficient as that by the gas-discharge counter with the filter. The method for recording the low-energy 45Ca beta-radiation in the combination with 32P in one tissue specimen by the end-window gas-discharge counter and filter is more efficient to some extent that the calculation in the liquid scintillation counter.
Assuntos
Radioisótopos de Carbono , Radioisótopos de Fósforo , Radiometria/métodos , Contagem de Cintilação/métodosRESUMO
The effects of UV-light (253,7 nm) on the structure of DNP and its protein and nucleic components were studied. The formation of protein-DNA covalent bonds in DNP-200 A at low ionic strength was confirmed. Under certain irradiation conditions more than 80% of protein may be linked to the DNA; all histone fractions were linked to the same extent and at the same rates. The local denaturation of DNA in the region of photo-induced thymine-thymine dimers and other photoadducts dramatically changed the rate and specificity of the effects of staphylococcal nuclease, which directly affected the composition and size of the fragments formed. A possible application of UV-irradiated DNP for various structural investigations is discussed.
Assuntos
Desoxirribonucleoproteínas/efeitos da radiação , Nucleoproteínas/efeitos da radiação , Raios Ultravioleta , Animais , Bovinos , DNA/efeitos da radiação , Histonas/efeitos da radiação , Nuclease do Micrococo , Desnaturação de Ácido Nucleico , Ligação ProteicaAssuntos
Polietilenos , Contagem de Cintilação/instrumentação , Difusão , Luz , Permeabilidade , Fatores de TempoRESUMO
A comparative kinetic study has been made of tetranitromethane nitration of tyrosine residues in deoxyribonucleoprotein preparation (DNP) treated with EDTA and/or UV light at lambda=253.7 nm, as well as obtained by enzymatic digestion of nucleosomes. UV-light-induced protein-DNA linkages stabilize the structure of the preparation, whereas the action of chelate agents causes DNP-200 angstrom leads to DNP-100 angstrom transfer. Comparison of kinetic data and the results of the amino acid analysis of individual fractions of nitrated histones allowed to conclude that the differences observed between the degree and the rate of nitration are due to internucleosomic interactions which form the supernucleosomic structure of DNP.