Immunocytochemical localization of tubulin with colloidal gold in cilia of rabbit tracheal epithelial cultures

Ciliated tracheal epithelia cell cultures were investigated immunocytochemically with anti-tubulin and colloidal gold. When rabbit tracheal cultures were fixed in paraformaldehyde, treated with acetone, anti-tubulin and a second antibody coupled to FITC, fluorescence was associated with cytoskeletal and axonemal microtubules. Cilia covering the apical surface of the ciliated tracheal cells fluoresced very brightly thus facilitating identification of this cell type. Electron microscopy of tracheal cultures fixed as above, treated with Triton-X 100 and incubated in anti-tubulin and protein A coupled to colloidal gold resulted in the highly specific localization of tubulin in ciliary axonemes and basal bodies. Omission of primary or secondary antibody resulted in extremely low levels of fluorescence while no colloidal gold particles could be detected in cultures at the electron microscopy level when rabbit anti-tubulin was omitted.     

Nucleotide sequence of the 5'-terminal region of rat 18S ribosomal DNA

The 5'-terminal 597 base-pairs (bp) of the Sprague-Dawley rat 18S ribosomal RNA gee and 10 bp of the adjoining transcribed spacer have been sequenced. Previously sequenced 10 large oligonucleotides of rat 18S RNA were located in this region. This mammalian sequence has been compared with the known sequences of yeast and frog 18S rDNA's. The analysis indicates that 534 bp of the 597 bp (89%) are conserved between rat and frog sequences but only 75% of the nucleotides are conserved between rat and yeast in this region. Two large and two small sections have been identified where insertions have been introduced during evolution. Of these 58 bp long inserted sections of the rat rDNA sequence, 50 bp (86%) were G-C base-pairs.     

Preparation and use of the poly-l-lysine-gold probe: a differential marker of glomerular anionic sites

Summary The conditions required for the production of a polylysine-coated gold (PL-G) complex, which shows optimal sensitivity for the demonstration of tissue anionic sites, expressed under different conditions of pH have been investigated. Problems encountered with this complex have been compared with those found with other methods of conjugation of polylysine to colloidal gold. The performance of a bovine serum albumin (BSA)-stabilized PL-G complex was examined against other PL-G conjugates, including complexes that are commercially available, for the detection of heterogeneous glomerular anionic site populations, expressed at pH 2.5 and pH 7.0.     

Halothane inhibits the neurotoxin stimulated [14C]guanidinium influx through 'silent' sodium channels in rat glioma C6 cells

We have investigated the effect of pharmacological agents on [14C]guanidinium ion influx through sodium channels in C6 rat glioma and N18 mouse neuroblastoma cells. The sodium channels of the N18 cells can be activated by aconitine alone, indicating that they are voltage-dependent channels. In contrast, sodium channels in the C6 cells require the synergistic action of aconitine and scorpion toxin for activation and are therefore characterized as so-called silent channels. The general anesthetic halothane used at clinical concentrations, specifically inhibited the ion flux through the silent sodium channel of C6 rat glioma cells. The voltage-dependent channels of the N18 cells were insensitive to halothane at the concentrations tested.