Biochemical interactions between the pollen and the pistil allow plants fine control over fertilization. S-RNase-based pollen rejection is among the most widespread and best understood of these interactions. At least three plant families have S-RNase-based self-incompatibility (SI) systems, and S-RNases have also been implicated in interspecific pollen rejection. Although S-RNases determine the...

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...

Escherichia coli RNase E (Eco-RNase E), encoded by rne (Eco-rne), is considered the global RNA decay initiator. Although Eco-RNase E is an essential gene product in E. coli, some bacterial species, such as Bacillus subtilis, do not possess Eco-RNase E sequence homologues. B. subtilis instead possesses RNase J1/J2 (Bsu-RNase J1/J2) and RNase Y (Bsu-RNase Y) to execute RNA decay. Here we found th...

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 ...