Glycosides of marine invertebrates. XVI. Cucumariogenin from glycosides of the holothurianCucumaria fraudatrix
A new genin of the holostane series has been isolated by the acid hydrolysis of the glycosidic fraction of the holothurianCucumaria fraudatrix. It has been shown that this genin is the native alycone of glycoside G1 from the same holothurian. The structure of the genin has been established as 16β-acetoxyholosta-7,24-dien-3β-ol.
Chemical studies of marine invertebrates—II : Terpenoids—LVIII Griseogenin, a new triterpenoid sapogenin of the sea cucumber halodeima grisea l.
Abstract Chemical degradation coupled with extensive physical measurements has lead to structure V for griseogenin. The correctness of this structure has been confirmed by correlation with the known sapogenin, 22,25-oxidoholothurinogenin (I).
THE IRON-ACETOCARMINE METHOD OF FIXING AND STAINING CHROMOSOMES
A short description of this procedure was given in Vol. 55 of the American Naturalist, pp. 573â€”574. The method has now been used almost daily for five years, and certain improvements have suggested themselves. The solution can be prepared by mixing about equal volumes of glacial acetic acid and water. To this is added powdered carmine in excess. The liquid is then â€ ? just brought to boil, cooled, and decanted. To the red solution there are then added a few drops of a solution of ferric hydrate in 50 per cent. acetic acid, to act as a mordant. The amount of iron varies with different objects. Too much produces a precipitate in a short time. The more