Academy of science of the GDR

Leipzig, Germany

Academy of science of the GDR

Leipzig, Germany
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Junghans P.,Academy of science of the GDR | Schrader G.,Medical Academy Erfurt | Faust H.,Academy of science of the GDR | Wagner B.,Academy of science of the GDR | And 2 more authors.
Isotopes in Environmental and Health Studies | Year: 2012

During the 29th Soviet Antarctic Expedition in Novolazarevskaya from March 1984 to March 1985, the protein and energy metabolisms were studied in six expeditioners from the German Democratic Republic. The investigations were carried out at the beginning of the expedition (May), during the polar night (July) and during the polar day (December). The effect of a special stress situation (sledge trek in April 1984) was investigated in one subject. The stable nitrogen isotope 15N was used to study the protein metabolism. The assessment of the energy metabolism was based on the oxygen consumption, which was determined by means of a spirograph. In addition, the vital capacity, the breath minute volume, the blood pressure, etc. were measured. The following results were obtained: During the polar night, the utilisation of the dietary proteins and the whole body protein synthesis calculated by means of the 15N excretion of the total nitrogen in urine were greater (73.6 ± 0.9 % and 3.48 ± 0.17 g protein d-1 kg-1, n = 3) than the respective values during the polar day (69.7 ± 1.2, p < 0.05, n = 3 and 3.05 ± 0.07, p < 0.05, n = 3) and at the beginning of the expedition (69.6 ± 1.4, p < 0.02, n = 5 and 2.81 ± 0.09, p < 0.01, n = 5). The lowest values (58.0 % and 2.43 g protein d-1 kg-1) were obtained in the subject after the trek. The resting metabolic rate in kJ d-1 m-2) was decreased during the polar night (45.6 ± 5.0, n = 4) in comparison with the polar day (61.5 ± 11.3, n = 3) and the beginning of the expedition (52.3 ± 9.6, n = 4) with p < 0.01 in both cases. © 2012 Taylor & Francis.


Krumbiegel P.,Academy of science of the GDR
Isotopes in Environmental and Health Studies | Year: 2012

In order to achieve better mutual understanding, a uniform and unambiguous language concerning certain terms, symbols, units, and nomenclature in stable isotope - especially in 15N tracer technique has been recommended. In particular, some definitions of fundamental terms, some nomenclature rules for stable isotopically labelled compounds and some symbols and units in the formula language of isotope stoichiometry are given. Recent fundamental recommendations of the IUPAC have been accepted as a basis, to which, if necessary, specialities of stable isotope chemistry, especially 15N application are added or adapted. © 2012 Copyright Taylor and Francis Group, LLC.


Jonas C.,Academy of science of the GDR
Isotopes in Environmental and Health Studies | Year: 2012

Almost 30 years ago, the stable isotope 15N had covered a wide field of application in science and technology. With the preparation of the first smaller amounts of 15N in 1958, an intensive work of research and development started for the production, analysis, and application of 15N in the GDR. In this publication, activities of research and development for 15N production using the principle of chemical exchange in the system NOx/HNO3 from a laboratory scale to the introduction into chemical industry are described and new projects reported. © 2012 Copyright Taylor and Francis Group, LLC.


Junghans P.,Academy of science of the GDR | Wagner B.,Academy of science of the GDR | Nickel A.,Academy of science of the GDR | Faust H.,Academy of science of the GDR
Isotopes in Environmental and Health Studies | Year: 2012

In the present paper, a survey of methods applied to the interpretation and evaluation of tracer kinetic data is given. For their mathematical description, both compartmental and non-compartmental models, such as the modified model of Sprinson and Rittenberg, the San Pietro-Rittenberg model, two models of the albumin metabolism and a 10-pool model of the N and protein metabolism were used. By means of single or multiple pulse, infusion and priming techniques, the N and protein metabolism in various metabolic states (e.g. healthy man, pathological and stress conditions, therapeutic treatments) were studied. © 2012 Copyright Taylor and Francis Group, LLC.


PubMed | Academy of science of the GDR
Type: Journal Article | Journal: Planta | Year: 2013

The biotransformation of abscisic acid (ABA) was studied in cell suspension cultures of Lycopersicon esculentum. The ABA was converted by the cells to phaseic acid, nigellic acid, dihydrophaseic acid, abscisic acid--D-glucopyranosyl ester (ABA-Glc) and other ABA and phaseic acid conjugates. Investigation of their cellular distribution showed that the conjugated forms were located only in the vacuoles whereas ABA and its acidic metabolites were found mainly in the extravacuolar fractions. Our results, together with a number of studies on the increase of ABA-Glc as a response to stress, allow us to propose that ABA-Glc is irreversibly compartmented in the vacuoles of plant cells.


Endoproteolytic activities (EC 3.4.22. and 23.) of cell-free extracts of Euglena gracilis, measured by autolysis and azocaseinolysis, vary considerably during the culture growth cycle. They are high in the lag phase, drop sharply up to the mid-logarithmic phase, and then rise again reaching the initial high levels in the stationary phase. This pattern has been observed for both the soluble and the particulate proteolytic activities of four cell types differing with regard to the developmental state of the chloroplast: dark-grown, light-induced, and light-grown wild-type cells, as well as light-grown apoplastic W3BUL mutant cells, all on a glucose-based medium. Therefore, the activity of the main intracellular proteinases is neither directly nor indirectly light-regulated, but seems to be controlled by the availability of nutrients. Endogenous inhibitors of proteinases could not be detected. Cysteine proteinase activity has been found in the soluble and the particulate fractions, but aspartic proteinase activity in the latter ones only. Different cysteine proteinases may be present in the two fractions, during the different growth phases, and in the four cell types studied.


PubMed | Academy of science of the GDR
Type: Journal Article | Journal: Isotopes in environmental and health studies | Year: 2012

During the 29th Soviet Antarctic Expedition in Novolazarevskaya from March 1984 to March 1985, the protein and energy metabolisms were studied in six expeditioners from the German Democratic Republic. The investigations were carried out at the beginning of the expedition (May), during the polar night (July) and during the polar day (December). The effect of a special stress situation (sledge trek in April 1984) was investigated in one subject. The stable nitrogen isotope (15)N was used to study the protein metabolism. The assessment of the energy metabolism was based on the oxygen consumption, which was determined by means of a spirograph. In addition, the vital capacity, the breath minute volume, the blood pressure, etc. were measured. The following results were obtained: During the polar night, the utilisation of the dietary proteins and the whole body protein synthesis calculated by means of the (15)N excretion of the total nitrogen in urine were greater (73.60.9 % and 3.480.17g protein d(-1)kg(-1), n=3) than the respective values during the polar day (69.71.2, p<0.05, n=3 and 3.050.07, p<0.05, n=3) and at the beginning of the expedition (69.61.4, p<0.02, n=5 and 2.810.09, p<0.01, n=5). The lowest values (58.0 % and 2.43g protein d(-1)kg(-1)) were obtained in the subject after the trek. The resting metabolic rate (in kJd(-1)m(-2)) was decreased during the polar night (45.65.0, n=4) in comparison with the polar day (61.511.3, n=3) and the beginning of the expedition (52.39.6, n=4) with p<0.01 in both cases.


PubMed | Academy of science of the GDR
Type: Journal Article | Journal: Isotopes in environmental and health studies | Year: 2012

In the present paper, a survey of methods applied to the interpretation and evaluation of tracer kinetic data is given. For their mathematical description, both compartmental and non-compartmental models, such as the modified model of Sprinson and Rittenberg, the San Pietro-Rittenberg model, two models of the albumin metabolism and a 10-pool model of the N and protein metabolism were used. By means of single or multiple pulse, infusion and priming techniques, the N and protein metabolism in various metabolic states (e.g. healthy man, pathological and stress conditions, therapeutic treatments) were studied.

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