Protofilament number in microtubules in cells of two parasitic nematodes

The parasitic nematodes, Ascaridia galli and Trichostrongylus colubriformis, were prepared for electron microscopy with fixatives containing tannic acid, which allowed their microtubule protofilament number to be examined. In contrast to many mammalian tissues, the nematodes did not contain microtubules with 13 protofilaments. Ascaridia galli contained microtubules with 11 protofilaments in all tissues examined, including nerve, intestinal, pharyngeal, and hypodermal cells. Trichostrongylus colubriformis contained nerve cells, known as microtubule cells, with bundles of larger microtubules (approximately 30 nm in diameter) with 14 protofilaments. The microtubules in these cells did not appear to be continuous for the entire length of the axon. Other cells examined in T. colubriformis, including nerve, intestinal and pharyngeal cells, contained two distinct types of microtubules, one with 11 protofilaments and an approximate diameter of 25 nm, and one with 12 protofilaments and an approximate diameter of 27 nm. All cell types examined contained both types of microtubules.     

Flagellar regeneration of the trypanosome Crithidia fasciculata involves post-translational modification of cytoplasmic alpha tubulin.

Deflagellation of Crithidia fasciculata stimulated formation of new flagella and maximized production of alpha 3 tubulin. Continuous labeling during reflagellation revealed that alpha 1, 2, and 3 tubulins were formed, whereas the polyadenylated RNA translation products lacked alpha 3 isoform. Pulse-chase labeling experiments demonstrated that alpha 3 was a post-translational modification of cytoplasmic alpha tubulin.     

Influence of the antimicrotubule agent,mebendazole, on the secretory activity of intestinal cells ofAscaridia galli

Summary The anthelmintic compound mebendazole caused the disappearance of microtubules in the intestinal cells ofAscaridia galli. Electron microscopy revealed that soon after the microtubules disappeared there was an accumulation of secretory vesicles near the golgi areas. subsequently many of these vesicles aggregated forming dense large vesicles near the terminal web of the intestinal cells. This provides further evidence for the involvement of microtubules in the secretion of products from eukaryotic cells. It seems likely that inhibition of microtubule directed secretory functions in various cell types is an important function in the anthelmintic activity of the benzimidazole carbamates.     

Purification and assembly in vitro of tubulin from Trypanosoma brucei brucei.

Trypanosome tubulin was purified to near homogeneity by chromatography on DEAE-Sephadex, Amicon filtration and assembly-disassembly in vitro. Polymerization of the tubulin in vitro yielded long, structurally normal, microtubules and some sheet structures on addition of GTP and incubation at 37 degrees C, in either the presence or the absence of Mg2+. Tubulin assembly was disrupted by glycerol and a selection of microtubule-reactive drugs. Immunological analysis of the purified tubulin revealed tyrosinated and acetylated alpha-tubulin, in addition to defining the migration characteristics of the alpha- and beta-tubulin on one-dimensional SDS/polyacrylamide gels. This is the first isolation of trypanosome tubulin with the ability to form structurally normal microtubules independent of the addition of taxol or nucleating microtubule fragments. The development of the purification procedure thus provides an important step for subsequent study of microtubule-associated protein-tubulin and plasma-membrane-microtubule cytoskeleton interactions of trypanosomes, and increases the potential for development of tubulin-based anti-trypanosome drugs.     

Detection of areas of wall differentiation in fungi using fluorescent staining

Fungal colonies were stained with a fluorescent brightner, Calcofluor White M2R New. When viewed using ultraviolet light certain hyphal regions showed intense fluorescence, whereas others showed a lower intensity fluorescence. The apical 10 μm of leadingBotrytis cinerea hyphae showed intense fluorescence. Developing septa and side branches also showed this intense localised fluorescence. Calcofluor staining of hyphae and their subsequent growth illustrated the phenomenon of tip extension.     

Familial translocation t(3q+;8q−) studied by banding with Giemsa staining

Summary We have studied in cultured blood lymphocytes a familial translocation by banding with Giemsa staining, and have unequivocally identified the translocated chromosomes as Nos. 3 and 8, and besides we have established without doubt that the translocation has occurred between the short arm of chromosome No. 3 and the long arm of chromosome No. 8.

---

Zusammenfassung Mit Hilfe von Bandenmustern, die mit Giemsafärbung zu erzielen sind, wurde eine familiäre Translokation in Lymphocytenkulturen untersucht. Die translozierten Chromosomen konnten eindeutig als Nr. 3 und Nr. 8 identifiziert werden; außerdem wurde zweifelsfrei festgestellt, daß die Translokation zwischen dem kurzen Arm von Nr. 3 und dem langen Arm von Nr. 8 erfolgt ist.

     

Differential and developmental expression of beta-tubulins in a higher plant

By using two-dimensional gel electrophoresis and immunoblotting, we have analyzed the expression of beta-tubulin isotypes in the higher plant, carrot. We report a complex expression of beta-tubulins that is dependent on the developmental stage of the tissues analyzed. Consequently, each tissue examined can be identified by its unique composition of beta-tubulins. In total, there are six electrophoretically separable beta-tubulins. In no tissue, however, is there less than two or more than five beta-tubulins. Within this framework we have detected a beta-tubulin specific to seedling tissue beta 6, and a beta-tubulin, beta 5, that is found only in the vegetative tissues of the mature plant. Traced from stem to midrib to leaf lamina, the beta 5 isotype becomes progressively dominant relative to beta 1. Another beta-tubulin isotype, beta 4, appears in marked abundance in immature and mature stamens. In isolated mature pollen the beta 4-tubulin overwhelmingly predominates the ubiquitously expressed beta 2-tubulin isotype. The remaining beta-tubulin isotypes also have specific expression programs with beta 1 present in all tissues except pollen and beta 3 absent only from pollen and leafy tissues.