The iturin and fengycin families of lipopeptides are key factors in antagonism of Bacillus subtilis toward Podosphaera fusca.

Podosphaera fusca is the main causal agent of cucurbit powdery mildew in Spain. Four Bacillus subtilis strains, UMAF6614, UMAF6619, UMAF6639, and UMAF8561, with proven ability to suppress the disease on melon in detached leaf and seedling assays, were subjected to further analyses to elucidate the mode of action involved in their biocontrol performance. Cell-free supernatants showed antifungal activities very close to those previously reported for vegetative cells.

Synthesis and properties of cationic oligomeric surfactants.

Three series of new oligomeric cationic surfactants were synthesized. These amphiphiles are trimeric and tetrameric oligomeric quaternary ammonium chlorides, with spacer groups of different lengths separating the individual surfactant fragments. The properties of the compounds, such as Krafft temperatures, surface activity, micellization, viscosifying effects, foaming and solubilizing capacity, are studied.

Photophysical Behavior of a New Gemini Surfactant in Neat Solvents and in Micellar Environments.

A novel fluorescent gemini surfactant, 1,4-bis-(2'-(N-dodecyl pyridinio-4"-yl)ethenyl)benzene dibromide, abbreviated BDPEBB, has been synthesized and its photophysical properties have been studied in different environments. BDPEBB has a limited solubility in alcohols where it is found in aggregate form at concentrations>/=1 mM. In other solvents, e.