NOTAS E RESENHAS

PRONUNCIAMENTO DE UM GEÓGRAFO - Getúlio Vargas BARBOSA RECURSOS HíDRICOS E METODOLOGIA DE PESQUISA - Myrian Cecília R. PROCHNOW ROTEIRO DE INTERPRETAÇÃO DE IMAGENS E TRABALHO DE CAMPO EM GEOMORFOLOGIA (ESCALAS INFERIORES A 1:100.000) - Luiz Carlos Soares GATTO IDEOLOGIA E ENSINO DA GEOGRAFIA - Silvio Carlos BRAY CONTRIBUlÇÕES À GEOGRAFIA HUMANA E ECONÔMICA - Antônio CHRISTOFOLETTI GEOGRAFIA DOS PAÍSES EM DESENVOLVIMENTO - Antônio CHRISTOFOLETTI GEOGRAFIA POLlTICA E DESENVOLVIMENTO DESIGUAL - Antônio CHRISTOFOLETTI REGIONALIZAÇÃO, PLANEJAMENTO E GEOGRAFIA REGIONAL - Antônio CHRISTOFOLETTI CRIME URBANO E GEOGRAFIA APLICADA - Odeibler Santo GUIDUGLI AGRICULTURA NO TERCEIRO MUNDO - Lúcia Helena O. GERARDI ASPECTOS GEOGRÁFICOS DA SAÚDE - Wilson JACOMINI DESENVOLVIMENTO DE CENTROS COMERCIAIS - Silvana Maria PINTAUDI ANÁLISE INTERDISCIPLINAR DO LAGO BIWA - Myrian Cecília Rolim PROCHNOW PLANEJAMENTO DO USO DA TERRA E SENSORIAMENTO REMOTO - Gilberto José GARCIA PROGRESS IN PHYSICAL AND IN HUMAN GEOGRAPHY 1984 - Antônio CHRISTOFOLETTI     &nbsp

Transmission electron microscopy for characterization of acrosomal damage after Percoll gradient centrifugation of cryopreserved bovine spermatozoa

The objective of this study was to characterize acrosomal ultrastructure following discontinuous Percoll gradient centrifugation of cryopreserved bovine sperm. Semen was collected from six bulls of different breeds and three ejaculates per bull were evaluated. Frozen semen samples were thawed and the acrosomal region of sperm cells was evaluated by transmission electron microscopy (TEM) before (n = 18) and after (n = 18) Percoll centrifugation. The evaluation of 20 sperm heads from each of the 36 samples analyzed ensured that a large number of cells were investigated. The data were subjected to analysis of variance at a level of significance of 5%. Percoll centrifugation reduced the percentage of sperm exhibiting normal acrosomes (from 61.77 to 30.24%), reduced the percentage of sperm presenting atypical acrosome reactions (from 28.38 to 4.84%) and increased the percentage of sperm exhibiting damage in the acrosome (from 6.14 to 64.26%). The percentage of sperm with typical acrosome reactions was not significantly different before (3.70%) and after (0.67%) centrifugation. TEM distinguished four different types of acrosomal status and enabled ultrastructural characterization of acrosomal injuries. The percentage of sperm exhibiting normal acrosomes decreased and damage in the acrosome was the most frequent acrosomal injury with the Percoll gradient centrifugation protocol utilized