Sperm aggregation by water extracts from two Bursera species.

Some plants have more than the common utility value, as is the case of some members of the Bursera species such as the Mexican copal, a plant used for worship. Water extracts of several plants have vaginal contraceptive properties. The authors evaluated the sperm agglutinating activity of two Bursera species on human and boar sperm. Extracts from stems and leaves were obtained. Capacitated sperm samples were used in all cases. There were different agglutinating capacities, which were not observed in the vehicle-only samples. The most frequent sperm agglutination response was that involving the heads. Agglutinating activity was higher from stem- than leaf-derived extracts. The results indicate that proteins present in the extracts are responsible for the aggregation of sperm heads.

Intranuclear network of 3-5 nm and 8-10 nm fibers in EL-4 lymphoma cells.

While much evidence indicates a high degree of spatial organization in the nucleus, the underlying molecular structures that support it remain poorly characterized. By extracting with high concentrations of RNase A in a modification of the sequential extraction protocol of Penman, we have identified a novel intranuclear network in the mouse lymphoma cell line, EL-4. Micrographs of embedment-free sections of extracted cells reveal anastomosing filaments of two different diameters: 3-5 nm and 8-10 nm. The 3-5-nm filaments are interconnected in many junctions and appear to blend smoothly into each other. The 8-10-nm fibers frequently split into two 3-5-nm filaments. Some 3-5-nm fibers appear to be connected at 90 degrees angles with the 8-10-nm fibers. All junctions are smooth with no apparent junction protein. Flow cytometric analysis of RNase A- (and DNase I-) extracted nuclear matrices indicates that they do not contain significant amounts of protein that react with anti-actin and anti-vimentin monoclonal antibodies. Extraction of EL-4 nuclear matrices with high salt does not reveal 8-10-nm core filaments described after similar treatment of tumor cell lines of cervical and mammary origin. The novel characteristics of the core filaments in EL-4 lymphoma cells may reflect cell-type specificity of the nuclear matrix.