A rapid procedure for screening and isolating oxygenated free fatty acid metabolites from plants and natural waters.

A rapid method of isolating a relatively pure fraction of oxygenated fatty acids from plants and natural waters is described. These metabolites were isolated from aqueous extracts using octadecylsilyl silica in a reverse-phase batch extraction method. The extraction method, together with reverse-phase analytical high pressure liquid chromatography (HPLC), was used to establish a routine screening method for the presence of these compounds in a variety of natural sources. A reverse-phase preparative HPLC purification method is also described.

Use of selected freshwater bivalves for monitoring organochlorine pesticide residues in major Mississippi stream systems, 1972-73.

Seven species of freshwater Pelecypoda, Amblema costata, Corbicula manilensis, Elliptio crassidens, lampsilis anadontoides, Lampsilis claibornensis, Megalonaias gigantea, and Plectomerus dombeyanus, were collected and monitored for pesticide content during 1972 and 1973. Thirteen collection sites, representing five major river basins in the state of Mississippi, were sampled and compared. During the 24-month study, 26 water samples and 58 claim samples from the five river basins were analyzed. Individual samples weighed from 8 g to 20 g and consisted of 1-30 clams, depending on size. Residues of toxaphene and methyl parathion were found only in 1973 water samples. The study shows that freshwater clams are effective monitors of pesticide content. The tendency of clams to concentrate pesticides and their corresponding ability to eliminate them varies with species. Significant reductions in DDT and a corresponding buildup of p,p'-TDE were noted in 1973, following the limitations on the use of DDT and large-scale flooding throughout the state.

A large scale quasi-crystalline lamellar lattice in chloroplasts of the green alga Zygnema.

A quasi-crystalline lamellar lattice was observed in chloroplasts of the filamentous green alga Zygnema. The lattice does not appear in the cells until cultures are at the end of the log phase of growth. Pseudograna are also present and become more numerous towards the middle of the log phase. The three-dimensional lattice superficially resembles the configuration of cubic prolamellar bodies but is about 10 times larger and is entirely different in internal structure. The lattice is composed of one or two appressed thylakoids in a stroma matrix which is bounded on each side by a single thylakoid membrane. This multilayered sandwich of membranes and matrix occupies a position equivalent to the single membrane of a cubic prolamellar body.