Coordinated changes in enzyme activities of phenylpropanoid metabolism during the growth of soybean cell suspension cultures

Variations in teh activities of several enzymes of phenylpropanoid metabolism were studied in fermenter-grown cell suspension cultures of soyben (Glycine max).Concomitant large increases and subsequent decreases in the activities of phenylalanine ammonina-lyase (EC 4.3.1.5), cinnamic acid 4-hydroxylase, and two isoenzymes of p-coumarate:CoA ligase occurred prior to the stationary phase of the cell cultures. These findings represent a further example of an interdependent regulation of these enzymes of the general phenylpropanoid metabolism.The increases in all of these enzyme activities could be further enhanced by illunination of the cells.No comparable light effects and no significant changes were observed for the specific activity of an S-adenosylmethionine:o-dihydric phenol m-O-mehyltransferase and for the overall rate of the two-step reduction of feruloyl-CoA to coniferyl alcohol. These enzymatic reactions therefore appear to be regulated independently of the enzymes of the general phenylpropanoid metabolism.     

Der Turnover der Proteine in den Organen des Flußkrebses Orconectes limosus

Zusammenfassung Aus dem exponentiellen Abfall der spezifischen Aktivität nach einmaliger Injektion von L-Leucin-¹⁴C wurden die Halbwertszeiten der Gesamtproteine in den meisten Organen des Mußkrebses zu 8,5–19 Tagen bestimmt, in Leber und Niere der Maus zu 1,6–1,7 Tagen. Muskel- und Hämolymphproteine des Krebses zeigten weit längere Halbwertszeiten. Berücksichtigt man die Temperaturdifferenz von 25° unter Annahme eines Q ₁₀ von 2,0–2,5, so ergeben sich für Maus und Krebs etwa übereinstimmende Geschwindigkeiten des Proteinturnovers.

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Protein turnover in the tissues of the crayfish, Orconectes limosus

Summary The exponential decay of protein radioactivity after injection of L-Leucin-¹⁴C was measured in the different tissues of the crayfish, and in liver and kidney of the mouse. The half life time of tissue proteins was calculated to be 8.5 to 19 days in most crayfish tissues, 1.6 to 1.7 days in the mouse liver and kidney. Proteins of muscle and hemolymph of crayfish had much longer half life values. Taking into consideration the temperature difference of 25° C and assuming a Q ₁₀ of 2.0 to 2.5, the speed of protein turnover corresponds in the mouse and the crayfish.

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Mit Unterstützung der Deutschen Forschungsgemeinschaft.     

Partial tetra-allel crosses

Summary The construction of partical tetra-allel crosses (PTAC) is considered using BIB and PBIB designs with blocks of size four. It is shown how this can lead to certain types of balanced designs. An explicit procedure is given for constructing circulant PTAC's. The analysis of PTAC's — estimation of general effects of the lines involved and analysis of variance — is illustrated in terms of an example.

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Zusammenfassung In dieser Arbeit wird die Konstruktion von unvollständigen Tetra-Allelen (PTAC) mit Hilfe von unvollständigen Blockversuchsplänen (BIB- und PBIB-Plänen) betrachtet. Es wird gezeigt, wie dies zu gewissen ausgewogenen Plänen führen kann. Eine Methode zur Konstruktion von zirkularen PTAC's wird explizit angegeben. Die Analyse von PTAC's, d.h. das Schätzen von allgemeinen Effekten der betrachteten Linien und die Varianzanalyse, wird an einem Beispiel erläutert.

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Part of this work was supported by National Science Foundation Grant NSF-16491.

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Journal Paper No. J-5831 of the Iowa Agriculture and Home Economics Experiment Station, Ames, Iowa. Project No. 890.     

Eine Anlage zur monochromatischen Bestrahlung biologischer Objekte,ausgerüstet mit Interferenzfiltern und einer elektronisch geregelten 2,5 kW-Xenonlampe

Zusammenfassung Mit einer Lampe XBO 2500 W können monochromatische Quantenflüsse von der Größenordnung von 2 E s ^-1 bei =400 nm und 6 E s ^-1 bei =700 nm erzielt werden. Die Wellenlängenauswahl zwischen 300 und 900 nm erfolgt mit doppelten Interferenz-Bandfiltern (DAL), deren gesamter spektraler Untergrund unter 0,08% der durchgelassenen Strahlung bleibt. Die Strahlungsbelastung der Filter wird durch Vorschalten auswechselbarer selektiver Spiegel gemindert. Zusätzlich müssen die Filter an ihren Frontflächen mit Wasser gekühlt werden. Die Homogenität des Bestrahlungsfeldes wird durch einen Wabenkondensor erreicht. Eine Kaskadenregelung ermöglicht die zeitliche Konstanz der Bestrahlungsstärke. Technische Details, die Sicherheitsschaltungen einschließen, werden beschrieben.

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A monochromator system for the irradiation of biological material, utilizing interference filters and an electronically controlled 2.5 kW xenon arc

Summary A high pressure xenon arc lamp XBO 2500 W is used as a radiation source for the production of quantum fluxes of the order of 6 Einstein/sec at =700 nm and of 2 Einstein/sec at =400 nm. Wavelength selection between 300 and 900 nm is made by tandem interference filters of the band pass type (band width at half peak transmission approximately 16 nm), with a total transmission outside of passband<0.08%. The radiation load on the filters is reduced by the use of interchangeable selective mirrors. The front surface of the interference filters is cooled with de-ionized water (metal interference filters absorb more than 30% of the impinging visible radiation). Homogenity of irradiance is achieved by means of a honeycomb condensor. A simple cascaded feedback system sensitive to changes in lamp current and irradiance keeps radiation intensity constant with time. Technical details including safety devices are given.

     

The atokous-epitokous border is determined before the onset of heteronereid development in Platynereis dumerilii (Annelida,Polychaeta)

Summary In most nereids sexual maturation is accompanied by a dramatic reorganization of the body that enables swarming of the formerly benthic worms. However, a border exists between unchanged anterior (atokous) and metamorphosed posterior (epitokous) segments. The site of this atokous-epitokous border (a/e border) is different in sexually mature males and females of Platynereis dumerilii. There is no correlation between the total number of setigerous segments of a specimen and the location of the a/e border. The location of the a/e border and sexual development are affected neither by cutting off caudal segments of juveniles (including the prospective a/e border) nor by transecting the ventral nerve cord. When parapodia are transplanted from prospective epitokous regions to prospective atokous regions and vice versa, they maintain their original character during metamorphosis. The results presented here suggest that prospective atokous as well as epitokous characters are determined at or only very shortly after formation of the respective segments. Thus the a/e border is established well in advance of the onset of epitokous metamorphosis.     

Two substrate sites in the renal Na+-d-glucose cotransporter studied by model analysis of phlorizin binding and-d-glucose transport measurements

Summary Time courses of phlorizin binding to the outside of membrane vesicles from porcine renal outer cortex and outer medulla were measured and the obtained families of binding curves were fitted to different binding models. To fit the experimental data a model with two binding sites was required. Optimal fits were obtained if a ratio of low and high affinity phlorizin binding sites of 1:1 was assumed. Na⁺ increased the affinity of both binding sites. By an inside-negative membrane potential the affinity of the high affinity binding site (measured in the presence of 3 mM Na⁺) and of the low affinity binding site (measured in the presence of 3 or 90 mM Na⁺) was increased. Optimal fits were obtained when the rate constants of dissociation were not changed by the membrane potential. In the presence of 90 mM Na⁺ on both membrane sides and with a clamped membrane potential,K _D values of 0.4 and 7.9 M were calculated for the low and high affinity phlorizin binding sites which were observed in outer cortex and in outer medulla. Apparent low and high affinity transport sites were detected by measuring the substrate dependence ofd-glucose uptake in membrane vesicles from outer cortex and outer medulla which is stimulated by an initial gradient of 90 mM Na⁺(out>in). Low and high affinity transport could be fitted with identicalK _m values in outer cortex and outer medulla. An inside-negative membrane potential decreased the apparentK _m ofhigh affinity transport whereas the apparentK _m of low affinity transport was not changed. The data show that in outer cortex and outer medulla of pighigh and low affinity Na⁺-d-glucose cotransporters are present which containlow and high affinity phlorizin binding sites, respectively. It has to be elucidated from future experiments whether equal amounts of low and high affinity transporters are expressed in both kidney regions or whether the low and high affinity transporter are parts of the same glucose transport moleculc.     

AdaptivSearch: A Novel Iterative Algorithm for the Generation of n-dimensional Hypersurfaces Using an Adaptive Numerical Strategy

AdaptivSearch is the first adaptive strategy based algorithm for the rational and economical construction of n-dimensional hypersurfaces. AdaptivSearch works iteratively: At each step it parcels out the definition range into several triangles, evaluates the worst according to a built-in error criterion, and refines the approximation to the unknown function by choosing the barycenter of this partial area as the node to be calculated next. Based upon the error criterion, AdaptivSearch selectively approaches those parts of the hypersurface in which the curvature exhibits the strongest changes. Some examples of AdaptivSearch applications for both analytical functions and chemical model surfaces are given in order to demonstrate the behavior of the algorithm. These show its broad applicability and the usefulness, especially for chemical problems.     

On some formulas in a partnership model from the perspective of a semi-Markov process

Many deterministic models of sexually transmitted diseases, as well as population models in general, contain elements of stochastic or statistical reasoning. An example of such a model is that of Dietz and Hadeler (1988) concerning sexually transmitted diseases in which there is partnership formation and dissolution. Among the interesting formulas in this paper, which enter into the analysis of the model, are those for the expected number of partners a male or female has during a lifetime. To a probabilist such formulas suggest the possibility that some stochastic process may be constructed so as to yield these formulas as well as others that may be of interest. The principal purpose of this paper is to demonstrate that such a stochastic process does indeed exist in the form of a three state semi-Markov process in continuous time with stationary laws of evolution and with a one-step density matrix determined by four parameters which were interpreted as constant latent risk functions in the classical theory of competing risks. This construction of a semi-Markov process not only provides a framework for the systematic derivation of the formulas of Dietz and Hadeler but also suggests pathways,for extensions to the age-dependent case.This research was partially supported by NATO Grant D.890350