PRESENCE AND POSSIBLE IMPLICATIONS OF OPEN-RING CENTRIOLES, MULTIPLE BASAL CENTRIOLES AND BASAL CILIA IN NEONATAL HAMSTER BRONCHIOLES

In studying epithelio-stromal interactions in the neonatal hamster lun g, basal centrioles, basal cilia and open-ring centrioles attracted ou r attention. The same structures are also found in bronchiolar epithel ium of a 3-week-old fawn-hooded rat, indicating that they are not spec ific phenomena of hamster lung. Although cells with basal centrioles a re not common, they are more readily observed in a sample of bronchiol es at the second postnatal week as compared to the fourth neonatal day . The centrioles may often possess two Satellites and function as micr otubule organizing centers (MTOC). Open-ring centrioles are mature str uctures and also serve as MTOC. Apparently, triplets may de novo be ad ded to and/or degraded from an open-ring centriole. The basal cilia an d the cilia in the ciliated vacuoles/cysts, have a normal axonemal str ucture and may have a common origin from the basal centrioles. It is, however, unclear whether or not they are primary-like cilia. In additi on, presence of the multiple basal MTOC and some morphologic features point to a high microtubule-associated vesicular transport activity an d probably indicate an elevated interaction with the interstitium; thu s, the cells have a different polarization then normal ciliated cells.