The plant genus Lycium (Solanaceae) originated in the Americas and includes approximately 85 species that are distributed worldwide. The vast majority of Old World species occur in southern Africa and eastern Asia. In this study, we examine biogeographic relationships among Old World species using a phylogenetic approach coupled with molecular evolutionary analyses of the S-RNase self-incompati...

The Bacillus subtilis RNase M5 complex, responsible for the terminal maturation of 5 S rRNA, includes two proteins. One of these proteins is ribosomal protein BL16 (equivalent to Escherichia coli EL18); the other, the alpha component, is required for catalysis. The RNase M5 alpha component has been purified in bulk extensively, and the active polypeptide (Mr approximately 24,000) identified fol...

Self-incompatibility (SI) is found in approximately 40% of flowering plant species and at least 100 families. Although orchids belong to the largest angiosperm family, only 10% of orchid species present SI and have gametophytic SI (GSI). Furthermore, a majority (72%) of Dendrobium species, which constitute one of the largest Orchidaceae genera, show SI and have GSI. However, nothing is known ab...

Tetraploid sour cherry (Prunus cerasus L.) exhibits gametophytic self-incompatibility (GSI) whereby the specificity of self-pollen rejection is controlled by alleles of the stylar and pollen specificity genes, S-RNase and SFB (S haplotype-specific F-box protein gene), respectively. As sour cherry selections can be either self-compatible (SC) or self-incompatible (SI), polyploidy per se does not...

In cultures of certain streptococcal strains, RNA added as a carrier for streptolysin S (SLS) was hardly degraded, owing to deficiency of extracellular RNase activity. Production of RNA-SLS into culture supernatant was markedly reduced in the RNase-deficient streptococci. Even in these RNase-less strains, guanylic-acid rich oligonucleotides, polyG or trypan blue effectively induced SLS producti...

Because of their sessile lifestyle, plants have developed extensive mechanisms to safeguard their genetic information from one generation to the next. The WEE1 kinase is one of the guardians of genome integrity, being important during S-phase progression under replication stress. Knock-out plants for WEE1 (WEE1(KO)) show a hypersensitive response when grown on replication-inhibiting drugs. Rece...

Substrate recognition and cleavage by the bacterial RNase P RNA requires two domains, a specificity domain, or S-domain, and a catalytic domain, or C-domain. The S-domain binds the T stem-loop region in a pre-tRNA substrate to confer specificity for tRNA substrates. In this work, the entire S-domain of the Bacillus subtilis RNase P RNA is replaced with an artificial substrate binding module. Ne...

Bovine pancreatic ribonuclease A (RNase A) catalyzes the cleavage of the P-O(5') bond in RNA. Although this enzyme has been the object of much landmark work in bioorganic chemistry, the nature of its rate-limiting transition state and its catalytic rate enhancement had been unknown. Here, the value of k(cat)/K(m) for the cleavage of UpA by wild-type RNase A was found to be inversely related to ...

A variant of bovine pancreatic ribonuclease A has been prepared with seven amino acid substitutions (Q55K, N62K, A64T, Y76K, S80R, E111G, N113K). These substitutions recreate in RNase A the basic surface found in bovine seminal RNase, a homologue of pancreatic RNase that diverged some 35 million years ago. Substitution of a portion of this basic surface (positions 55, 62, 64, 111 and 113) enhan...

Using insertional mutagenesis, we have disrupted the RNase III gene, rnc, of the actinomycin-producing streptomycete, Streptomyces antibioticus. Disruption was verified by Southern blotting. The resulting strain grows more vigorously than its parent on actinomycin production medium but produces significantly lower levels of actinomycin. Complementation of the rnc disruption with the wild-type r...