Antennal sensory organs in the millipede Eurypauropus ornatus: Fine structure of the flagella and globulus

On the antennal tip of Eurypauropus ornatus are 3 threadlike sensilla—the flagella, and a single spheroid sensillum—the globulus. Each of the 3 flagella is innervated by 2 groups of sensory cells. One group contains 4 cells, the other, 5. All cells of the “four group” and 3 of the “five group” are comprised of single cilia and unbranched dendrites which extend along the lumen of the flagellum. Two cells of the “five group” have double cilia and pairs of unbranched dendrites. One pair also enters the flagellum and the other pair terminates beneath the flagellar base to form a concentric array of lamellae. No pores are present in the cuticular wall. Eight sensory cells innervate the globulus. They are arranged in 3 groups, one triplet and 2 pairs, in addition to a single cell. The single cell contains a pair of cilia whose unbranched dendrites differentiate into tubular bodies that are inserted into the base of the globulus. Each of the other 7 sensory cells has a single cilium. Their unbranched dendrites penetrate into the globulus in 3 groups as described for the sensory cells. The dendrites in each group terminate in an individual pore channel at the globulus tip and completely fuse with the electron-dense material that plugs the pore channel. Based on structural similarities to sensilla having known functions, it is probable that the flagella and the globulus are chemoreceptors, the former responding to odors, the latter sensitive to substances in aqueous solution.     

Effect of trypsin on the cell surface proteins of hepatoma tissue culture cells. Characterization of a carbohydrate-rich glycopeptide released from a calcium binding membrane glycoprotein.

Concentrations of trypsin that bring about aggregation of hepatoma tissue culture (HTC) cells also release from the cell surface an Mr = 55,000 glycopeptide fragment. This glycopeptide fragment also accumulates in the medium, including serum-free medium, as a normal consequence of membrane protein turnover. The trypsin-released glycopeptide is labeled when cells are grown in the presence of fucose or leucine before treatment of the cells with the protease. Similarly, the glycopeptide fragment can be labeled by reacting cells in situ by lactoperoxidase-catalyzed radioiodination or by tritiated borohydride reduction of cells treated first with neuraminidase and galactose oxidase. The tryptic glycopeptide fragment was purified by concanavalin A-Sepharose chromatography, and hydroxyapatite chromatography in the presence of dodecyl sulfate. The amino acid and carbohydrate composition was determined, as was the sensitivity of the purified glycopeptide to a variety of endo- and exoglycosidases. The purified glycopeptide contains an average of 17 sialic acid residues and hence, shows charge heterogeneity after electrophoresis in isoelectric focusing gels. The charge heterogeneity can be eliminated completely by treatment with neuraminidase. The glycopeptide after this treatment is homogeneous. The trypsin-sensitive membrane glycoprotein which is the source of the Mr = 55,000 glycopeptide was identified by two-dimensional gel electrophoretic analysis of labeled cells, treated or not treated with trypsin. This glycoprotein, which has an apparent molecular weight of 85,000 and forms a homodimer in the presence of calcium ions, was purified and its identity as the parent of the Mr = 55,000 glycopeptide was confirmed by showing that the same Mr = 55,000 fragment was released by trypsin from the purified glycoprotein as was released from the intact cells.     

The application of linear irreversible thermodynamics to biological growth

We measured the rate of cell biomass growth, the consumption of organic substrate, and the heat developed during growth. The relationship between thermodynamic efficiency and the rate of microbial growth was considered.     

Sexual differentiation in Mucor: Trisporic acid response mutants and mutants blocked in zygospore development

Spores of a minus strain of Mucor mucedo (Bref.) were treated with 1-methyl-[3-nitro]-1-nitro-soguanidine and mutants were isolated either by testing for zygophore induction with externally supplied trisporic acids (TA) or by mating with wild type plus colonies. Mutants were found defective (Tar^?) or temperature-sensitive (Tar-Ts) in their reaction towards trisporic acids, blocked or temperature-sensitive in their mating with plus strain (Mat^? or Mat-Ts) or temperature-sensitive in zygospore development (Zyg-Ts). The inability to react against externally supplied trisporic acids was not necessarily coupled with an inability to mate with plus strain (phenotype Tar^? Mat⁺). This indicated that the diffusion and uptake of trisporic acids is not a necessary prerequisite to the sexual interaction of Mucor mating types.