Uraninschwellen des Protoplasmas der BraunalgeStypocaulon scoparium

Ohne Zusammenfassung     

The enzymic estimation of glutamate and glutamine

A method of estimating glutamic acid is described, based on its dehydrogenation by glutamate dehydrogenase coupled, by means of N-methylphenazine methosulphate, to the reduction of tetrazolium salts. The method is suitable for the estimation of 0-0.3mumole of glutamic acid. The response is linear, but not stoicheiometric: possible reasons for this are discussed. If suitable precautions are taken, the use of a partially purified preparation of glutaminase makes it possible to estimate glutamine also.     

Die Wirkungsweise von Cercosporella herpotricboides Fron, dem Erreger der Halmbruchkrankheit des Getreides

In halt: 1. Einleitung und Aufgabenstellung.—2. Art und Ausmaß der Scnäden im Feld-versuch.—3. Wirkungen des Krankheitserregers auf Sommergetreide.—4. Bekämpfungsmöglichkeiten.—5. Besprechung der Ergebnisse.—Zusammenfassung.—Summary. —Literaturverzeichnis.     

The Metabolism of Serum Proteins in Neonatal Rabbits

1. Incorporation of S³⁵-labeled amino acids into serum proteins has been studied in neonatal and developing rabbits. It was found that, per unit weight, neonatal rabbits synthesized only about 1/36 of the gamma globulin, 1/7 of the beta globulin, ½ of the alpha globulin, and ⅛ of the albumin that an adult synthesized. The growing rabbit developed the ability to synthesize various serum proteins at different times. 2. Plasma volumes and serum protein concentrations were determined at different times during the growth period of the rabbit. Plasma volumes were found to be 1 and ½ times larger in newborn animals than in adults, with a gradual decline to the adult level. The total serum protein concentration at birth was about 60 to 65 per cent of the adult value and gradually increased with growth as the plasma volume decreased. 3. Half-lives of homologous albumin and gamma globulin were studied. The half-life of albumin in neonates was nearly twice as long as the half-life in adults, the latter value being reached at 1 month of age. The half-life of gamma globulin in neonates was more than twice as long as the half-life in adults and reached adult values at 2 to 3 months. 4. Attempts were made to alter serum protein metabolism. Gamma globulin synthesis early in life was augmented with antigen injections.     

Effect of Drying on Unexposed Autoradiographic Emulsion in Relation to Background

Unexposed blanks prepared from Kodak AR 10 stripping film were dried by 3 methods: (1) fast, open drying with a fan for 25 min, (2) slow drying in a desiccator for 6 hr, and (3) very slow drying in a desiccator for 24 hr. The number of background grains depended on the mode of drying. Fast drying (method 1) gave 0.7 grain per 100 μ², slow drying (method 2) gave 0.33 grain; very slow drying (method 3), only 0.17 grain. The increase of background after fast drying is assumed to be caused by the rapid shrinkage of wet emulsion. This causes an increase in the intraemulsion pressure which, in turn, sensitizes the silver bromide crystals to cause an increase in the number of developable grains.     

The pectinolytic enzyme of Selenomonas ruminantium

A cell-bound pectinolytic enzyme was isolated from cells of Selenomonas ruminantium and purified about 360-fold. The optimum pH and temperature for enzyme activity was 7.0 and 40°. The enzyme degraded polymeric substrates by hydrolysis of digalacturonic acid units from the non-reducing end; the best substrate was nona-galacturonic acid. Unsaturated trigalacturonate was also degraded, but 30% slower than the saturated analogue. The enzyme was classified as a poly (1,4-aP-D-galactosiduronate) digalacturono-hydrolase; EC 3.2.1.82. Another enzyme, hydrolysing digalacturonic acid to monomers, was also produced in a very small amount by this organism.     

Effects of Solar Radiation on Photoorientation,Motility and Pigmentation in a Freshwater Cryptomonas

The effects of solar radiation on motility, photoorientation and pigmentation have been studied in a freshwater Cryptomonas species. The diaphototactic orientation performed by the cells is impaired within about 90 min of solar radiation. Likewise, the percentage of motile cells within the population and the average velocity of the swimming cells decreases within about the same exposure time. This effect is not due to a thermal stress but rather seems to be caused by the solar UV-B component, since decreasing short wavelength UV radiation by means of an artificial ozone filter or UV cut-off filters increased the tolerated exposure time. Solar radiation also bleached the photosynthetic pigments of the cells as shown by absorption difference spectra.     

Detection of Petunia Asteroid Mosaic, Carnation Ringspot and Tobacco Necrosis Viruses in Ditches and Drainage Canals in a Grapevine-Growing Area in West Germany

A number of virus isolates were obtained from ditches and drainage canals in the Palatinate grapevine-growing area (‘Rheinpfalz’) in West Germany. By means of the immunoelectron microscopical decoration and the agar gel double diffusion tests these isolates were identified as petunia asteroid mosaic virus, carnation ringspot virus and tobacco necrosis virus strain D, respectively.