A comparison of isogenic RNase III+ and RNase III- strains of Escherichia coli shows that although both synthesize precursor and mature 16 S and 23 S ribosomal RNAs, the transient rRNA species of the RNase III- strain differ from those of the RNase III+ strain. The RNase III+ strain synthesizes p16 and p23 rRNA, whereas the RNase III- strain produces unstable 17 S, 18 S, "p23," 25 S and 30 S RN...

The flowering plant Solanum chacoense uses an S-RNase-based self-incompatibility system in order to reject pollen that shares the same genes at the S-locus (S-haplotype) with the style (an incompatible reaction). Two different models have been advanced to explain how compatible pollen tubes are protected from the cytotoxic effects of the S-RNase, sequestration of the S-RNase in a vacuolar compa...

Among the Rosaceae species, the gametophytic self-incompatibility (GSI) is controlled by a single multi-allelic S locus, which is composed of the pistil-S and pollen-S genes. The pistil-S gene encodes a polymorphic ribonuclease (S-RNase), which is essential for identifying self-pollen. However, the S-RNase system has not been fully characterized. In this study, the self-S-RNase inhibited the Ca...

The proteolysis of bovine pancreatic ribonuclease by subtilisin has been shown to involve the formation of an enzymically active intermediate which is further degraded to inactive products (1, 2). This paper describes the preparation of the modified active ribonuclease, RNase (S)l and its fractionation into two components, a peptide (S-peptide) and a protein (S-protein). Neither S-peptide nor S...

The proteolysis of bovine pancreatic ribonuclease by subtilisin has been shown to involve the formation of an enzymically active intermediate which is further degraded to inactive products (1, 2). This paper describes the preparation of the modified active ribonuclease, RNase (S)l and its fractionation into two components, a peptide (S-peptide) and a protein (S-protein). Neither S-peptide nor S...

Abstract Calcium ions are involved in plant self-incompatibility response as important signaling substances cells. In the sporophytic response, Ca 2+ enters stigma papilla cells and plays a key role inhibiting incompatible pollen tube growth. gametophytic reaction of Papaveraceae, female determinants style ( PrsS ) male PrpS recognize each other, promote extracellular influx into tube, destroy ...

Prunus fruit trees of the Rosaceae family exhibit S-RNase-based gametophytic self-incompatibility (GSI), which enables pistils to reject self-pollen by suppressing pollen tube elongation. In other plant species with GSI, it has been shown that this suppression consists two steps: first, slowing down elongation in middle part style and second, complete arrest involving programmed cell death. To ...

All preparations of ribonuclease-S so far reported have employed limited digestion of ribonuclease-A with subtilisin,' a bacterial proteinase from B. subtilis described by Giintelberg and Ottesen.' The original supply of this latter enzyme is now exhausted. Another sample of a crystalline proteinase from B. subtilis (NOVO Enzyme) has been shown to differ from the original in several respects,' ...

The Solanaceae, Rosaceae, and Scrophulariaceae families all possess an RNase-mediated self-incompatibility mechanism through which their pistils can recognize and reject self-pollen to prevent inbreeding. The highly polymorphic S-locus controls the self-incompatibility interaction, and the S-locus of the Solanaceae has been shown to be a multi-gene complex in excess of 1.3 Mb. To date, the func...