Minerals formed by organisms may either be simply a side-product of the metabolism or they carry a function, for which their properties and morphologies are controlled by the organism. The rst case, bioinduced mineralisation, was encountered in this work in the case of the precipitation of the mineral schwertmannite (Fe8O8(OH)6SO4) by the bacterial strain Leptospirillum ferrooxidans. In the lit...

weeks from the time the pellet was removed. At two-week intervals animals from the control group and from the test groups were sacrificed and the tumors removed. Only those tumors classed as adenocarcinomas on initial bi opsy have been included in this study. Fibroadenomas (which do not regress on removal of the estrone pellet) and the few carcinomas which contained large amounts of connective ...

Virus transformants (like cancer cells, cells transformed by X-ray or carcinogens, or those which have transformed spontaneously) exhibit a number of phenotypic changes which are usually associated, and which may be lost concurrently. That association is, however, not invariable. More particularly, the altered characteristics here studied (escape from contact inhibition of growth and susceptibi...

A new estuarine filamentous heterocystous cyanobacterium was isolated from intertidal sediment of the Lagoa dos Patos estuary (Brazil). The isolate may represent a new genus related to Cylindrospermopsis. While the latter is planktonic, contains gas vesicles, and is toxic, the newly isolated strain is benthic and does not contain gas vesicles. It is not known whether the new strain is toxic. It...

A simple procedure is described for the isolation of porcine growth hormone from the filtrate remaining after the adsorption of adrenocorticotropic hormone (ACTH) onto oxidized cellulose during the commercial manufacture of ACTH. Growth hormone is purified by ion exchange chromatography on diethylaminoethylcellulose. The purified hormone has a specific biological activity nearly twice that of t...