Exempel på aster

• The peripheral asters come into close apposition with the cortex.

• Indeed, the antibody stained the asters and (more strongly) the vesicular components attaching to the periphery of the mitotic apparatus.

• Although the paternal centrosome duplicated, the maternal centrosome in the centre of the egg aster did not divide.

• The microtubules of the male aster are arranged in a funnel-shaped array, all stretching to the fertilisation area in the cortex.

• Migration of the asters sets one in the centre of the egg and the other in the cortex.

• Microtubules of both asters reaching into the cortex cross each other cirumferentially.

• This indicates that neither aster is strongly attached to the cortex until the end of metaphase.

• The lower ('vegetal') spindle pole produces a much larger aster than the upper ('animal') spindle pole.

• Again, the microtubules of the central aster run along the pronuclear surface and reach the cell cortex.

• All microtubules associate with the meiotic spindle and asters.

• However, fully developed microtubule asters were not observed.

• These asters grow until the male pronucleus reaches its female counterpart and disintegrate afterwards.

• A small microtubule aster was observed in association with decondensed chromatin following nuclear transfer, suggesting the introduction of a somatic cell centrosome.

• In early metaphase, a bipolar spindle with broad poles and devoid of asters is formed.

• At metaphase the two equal-sized asters span the entire egg in a symmetrical arrangement.