Using RNase-gold labelling a comparative estimation has been made of the RNA content of the nucleoli and nucleolus-like inclusions in anther cells of Lilium henryi Thunb. Pretreatment with glow electric discharge prior to application of the RNase-gold labelling remarkably lowered the level of nonspecific adsorption and allowed specific labelling of RNA-containing structures. In the tapetal cells, the nucleoli, the perichromatin material and the dense bodies labelled heavily, but both the interchromatin region and the condensed chromatin did not bind the label. The nucleolus-like inclusions, which were found in the nucleoplasm of meiotic cells at the tetrad stage, and were termed ‘nuclear nucleolus-like bodies (NLBs)’ in the present study, also showed a high response compared with both the loosened and the condensed chromatin; this labelling was some 60% of that observed over the nucleoli of somatic cells. Another type of nuclear NLB was differentiated from the predominant type of NLB by a conspicuous electron opacity, reduced size, and strong labelling with the RNasegold complex, suggesting that some nuclear NLBs may be highly condensed. The labelling over the cytoplasmic nucleoloids (nucleolus-like inclusions found in the cytoplasm) was only 50 % of that over the nuclear NLBs, although both are similar in ultrastructural texture.
Synthesis and pharmacokinetic characterisation of a fluorine-18 labelled brain shuttle peptide fusion dimeric affibody