Rapid in vitro activation of corpora allata by extracted locust brain allatotropic factor

Brains of young (newly emerged) adult female locusts (Locusta migratoria migratorioides) and of mature (> 9 days old) locusts contain an extractable allatotropic factor, soluble in 100% methanol and in distilled water. This factor stimulates juvenile hormone III (JH III) synthesis and release from corpora allata (CA) that have been excised from donor locusts and then incubated with (radiolabeled methyl)-methionine in vitro in its presence. In addition to JH III, which is the major product synthesized by the CA, other hexanesoluble, radiolabeled compounds–-more polar than JH III–-are also released when CA are incubated in vitro. The activation of CA by the allatotropic factor is rapid and quickly declines when the factor is removed from the medium. Corpora allata excised from young females are marginally active and can be activated by brain allatotropic factor to less of an extent than CA of mature locusts. The content of allatotropic factor in brains of mature locusts is higher than that ascertained in brains of young females. Allatotropic factor is also present in the corpora cardiaca.     

Multiple labeling of cellular constituents by combining surface reflection interference and fluorescence microscopy

In this paper the technique for visualizing cytoskeleton in detergent-extracted cultured cells by surface reflection interference (SRI) microscopy after staining with the protein dye Coomassie Brilliant Blue (SRI-CooB technique) is used in conjunction with fluorescently-labeled antibodies or with other fluorescent probes to detect a number of constituents in the same cultured cell. Because SRI-CooB technique preferentially visualizes microfilament bundles along the ventral aspect of cells adhering to a glass substratum, we feel that this simple and rapid technique has great potential in studies of cell-substratum adhesiveness and of adhesion-related cytoskeletal organization.