Sensing,Threading, Orienting,and Cutting Polymers with Rigid-Rod Pores

This short review describes synthetic pores that are made from rigid-rod molecules and can bind oligo-and polymers such as polyacetylenes, p-oligophenyls, terpenoids, polypeptides, polysaccharides, and oligonucleotides. The spotlight is on recent breakthroughs to image the longtime elusive pore-polymer host-guest complexes as single giant pseudorotaxanes.     

Function of Lysosomes and Lysosomal Enzymes in the Senescing Corolla of the Morning Glory (Ipomoea purpurea)

The rapid senescence of the Ipomoea corolla is characterizedby the breakdown of protein and nucleic acids. At the onsetof wilting the activities of deoxyribonuclease (DNase), ribonuclease(RNase), and ß-glucosidase are increased dramatically,while other hydrolytic activities such as the actions of protease,aminopeptidase, -glucosidase, phosphatase, esterase, and -amylaseare only slightly changed. Isolated corolla discs show a course of senescence similar tothat of the intact organ. When floating on solutions of cycloheximidethe activities of DNase, RNase, and ß-glucosidasedo not increase. Actinomycin D inhibits the increase in RNaseactivity. It is concluded that protein synthesis is a prerequisitefor the changes in these enzyme activities in the senescingcorolla. The function of the lysosomal compartment in the process ofsenescence is illustrated by electron micrographs showing theautophagic activity of vacuoles. The last phase of senescenceis characterized by the breakdown of the tonoplast and completedigestion of the cytoplasmic constituents in the autolysingcells.