Four new Geosmithia species from bark beetles infesting indigenous South African trees.

Over the past two decades, numerous Geosmithia fungi have been isolated from the bodies and galleries of wood-boring beetles. However, this genus of asexual Sordariomycetes remains taxonomically and ecologically understudied, especially in the Southern Hemisphere. In South Africa, two prior surveys reported Geosmithia species from bark beetles, but neither thoroughly investigated species identities.

Influence of ligand valency on ligand-influenced monomer-dimer equilibrium systems and biological control mechanisms.

Two specific ligand-influenced monomer-dimer equilibrium systems are discussed. Each has a ligand-to-dimer subunit ratio of 0.5.

Protocols for use of ultrafiltration in determination of free ligand concentration and of complexity of ligand/protein interactions.

Analysis of a simple ligand/binding-protein association model predicts a decrease in the percentage of free hormone during ultrafiltration. Re-analysis of the original data validating ultrafiltration in free-ligand determinations (Sophianopoulos et al., Arch Biochem Biophys 1978;187:132-7) confirms this prediction.