|
|
|
|
|
| Mello,Maria Luiza S.; Maria,Sílvya S.; Tavares,Maria Cristina H.. |
| The survival of Triatoma infestans and of somatic cells from this species is affected by heat shock. In this study, we examined the cell death responses of male germ line cells from 5th instar nymphs 7 and 30 days after heat shock exposure (40ºC, 1 h). The preparations were stained by the Feulgen reaction and the TUNEL immunocytochemical assay. Apoptosis was elicited by heat shock, with positive TUNEL responses in spermatogonial chromatin and chromosomes, spermatids and sperm cells. Spermatogonia were most affected seven days after the shock whereas some spermatids and sperm cells exhibited DNA fragmentation only thirty days after heat shock. The rate of cell death varied among the cells. In some cases, cellular differentiation was unaffected by heat... |
| Tipo: Info:eu-repo/semantics/article |
|
| Ano: 2000 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572000000200011 |
| |
|
|
| Britto,Carmen M.C.; Mello,Maria Luiza S.. |
| "Pé-duro" (hard foot) is a rare breed of beef cattle of European (Bos taurus taurus) origin, originated in northern and northeastern Brazil. Y chromosome morphology, outer genital elements and other phenotypic characteristics were examined in 75 "pé-duro" bulls from the Empresa Brasileira de Pesquisa Agropecuária (Embrapa) herd in the Brazilian State of Piauí. The purpose was to investigate possible racial contamination with Zebu animals (Bos taurus indicus) in a cattle that has been considered closest to its European origin (B. t. taurus). The presence of both submetacentric and acrocentric Y chromosomes, typical of B. t. taurus and B. t. indicus, respectively, and the larger preputial sheath in bulls with an acrocentric Y chromosome indicated racial... |
| Tipo: Info:eu-repo/semantics/article |
|
| Ano: 1999 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47571999000300014 |
| |
|
|
| Maria,Silvya Stuchi; Vidal,Benedicto de Campos; Mello,Maria Luiza S.. |
| Nuclear image analysis of Feulgen-stained V79 fibroblasts after three days in culture was used to discriminate apoptotic cells and cells suspected to be undergoing apoptosis from control cells based on parameters such as the Feulgen-DNA content, degree of chromatin condensation and nuclear areas, in association with visual morphology. The fibroblasts were initially plated at a density of 10(5) cells/ml and incubated under optimal culture conditions without subculturing. Following confluency, the cells underwent contact inhibition apoptosis. Image analysis revealed three nuclear phenotypes which were defined in terms of their morphological characteristics and levels of chromatin condensation. A decrease in the amount of Feulgen-DNA was detected in apoptotic... |
| Tipo: Info:eu-repo/semantics/article |
|
| Ano: 2000 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47572000000100020 |
| |
|
|
| Monteiro,Ana Lúcia P.; Mello,Maria Luiza S.. |
| The binding of toluidine blue molecules to nucleic acid phosphates under conditions of competition with Mg2+ ions was studied in Trichosia pubescens polytene chromosome regions differing in composition and organization (RNA-rich areas and puffs, DNA puffs, heterochromatin). The aim was to find variability in the Mg2+ concentration at which metachromasy was completely prevented (= critical electrolyte concentration; CEC) and that could reflect differences at the level of nucleoprotein complexes in particular chromosome regions and developmental phases. Although high CEC values have been found in tightly packed chromatin such as that of heterochromatin zones, the CEC values for the other regions have proven to be affected not only by availability and... |
| Tipo: Info:eu-repo/semantics/article |
|
| Ano: 1998 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1415-47571998000200003 |
| |
|
|
|
