Hydrolysis of diepptide 2-naphthylamides by human muscle enzymes.

Human muscle enzymes that hydrolyse dipeptide 2-naphthylamides were separated by chromatography on DEAE-Sephadex. Evidence was obtained that these substrates are hydrolysed by arylamidase as well as by dipeptidyl aminopeptidases.     

High-molecular-weight glycoproteins are the major carriers of the carbohydrate differentiation antigens I, i and SSEA-1 of mouse teratocarcinoma cells.

The carriers of the carbohydrate differentiation antigens I, i and SSEA-1 were investigated in embryonal carcinoma cell lines of mouse and differentiated cell lines derived from them. Glycoproteins were studied by immunostaining ('Western blotting') of total cell lysates and immunoprecipitation from lysates of galactose oxidase/NaB3H4-labelled cells; glycolipids were investigated by immunostaining of thin layer chromatograms. The antigenic activities detected by immunofluorescence of cell smears were reflected in the antigenicities of high-molecular-weight glycoproteins. These were polydisperse and markedly susceptible to digestion with endo-beta-galactosidase. Only the I antigen was detected on minor glycolipids. These observations indicate that glycoproteins rather than glycolipids are the major carriers of carbohydrate differentiation antigens I, i and SSEA-1 in the teratocarcinoma cell lines.     

Graded footshock stress elevates pituitary cyclic AMP and plasma beta-endorphin, beta-LPH corticosterone and prolactin

Male rats were subjected to 15 min of various intensities of footshock current (0.0, 0.2, 0.4, 0.8, 1.6, 2.4, 3.2m A) on a variable interval schedule with an average intershock interval of 30 sec (30 shocks/15 min session). Each shock lasted 5 sec. Animals were sacrificed immediately after being removed from the shock box. Two similar studies were conducted. In the first experiment, rats were sacrificed by microwave irradiation and pituitary cyclic AMP levels were determined. In the second study, rats were decapitated and plasma hormones (prolactin, corticosterone, beta-endorphin, beta-LPH) were measured by radioimmunoassay. Although all biochemical indices of stress measured increased as shock intensity increased, some differences among the substrates measured were observed with respect to threshold intensity, range of proportional response and maximal response.     

Palaeolimnology in the English Lakes — some questions and answers over fifty years

In a review of work on 10 of the very numerous lakes of the English Lake District — work which involved co-operation between palaeolimnologists from different disciplines and between palaeo- and neolimnologists — the questions asked by the researchers are listed and it is shown which kind of lake has provided constructive answers. Complete and conformable sediment profiles covering the last ca 14 000 years are found in these lakes, but no single profile is optimal for study of the whole period. Knowledge of the pattern of sediment accumulation is necessary before the record in microfossils and changing sediment composition can be interpreted with confidence. The demonstration that the sediment-source material of these open lakes must have been largely allochthonous established the importance of the sediment column as a record of changes through time in the composition and stability of the soils of each catchment. These changes illustrate the influence of: