Microtubule polarity in the nutritive tubes of insect ovarioles.

The enormous numbers of microtubules within the nutritive tubes of hemipteran ovarioles are amenable to the hook-decoration technique for determining microtubule structural polarity, as they can be microdissected from ovarioles intact. This has allowed the correlation between the polarity of this continuously elongating complex of microtubules within a nutritive tube and the direction of transport along its length; and has shown that the plus or fast growing ends of the microtubules are all situated at the anterior end of a nutritive tube proximal to the trophic region from which synthesised materials are passed back towards the developing oocytes.