Über die energetische Kopplung der Nitritassimilation von Grünalgen an Atmung und Photosynthese

Summary Inhibitors and uncouplers of phosphorylation, i.e., arsenate, 2.4-dinitrophenol (DNP), pentachlorophenol (PCP), and carbonyl cyanide m-chlorophenylhydrazone (CCCP), inhibit the assimilation of nitrite by the green alga Ankistrodesmus braunii in the dark and in the light. In a medium containing nitrate, these inhibitors interrupt nitrate reduction at the level of nitrite. In phosphatedeficient algae, the assimilation of nitrite can be decreased by a concomitant, energy-dependent uptake of chloride and phosphate ions. These results support the assumption that high-energy phosphate is required for the assimilation of nitrite.CO₂ and glucose (after pre-illumination) increase nitrite assimilation in the light. Photosynthetic nitrite reduction is inhibited by 3-(3,4-dichlorophenyl)-1,1-dimethyl urea (DCMU), an inhibitor of oxygen evolution, and by disalicylidene-propanediamine-(1,3) (DSPD), an inhibitor of the photosynthetic reduction of ferredoxin.

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Abkürzungen CCCP Carbonylcyanid-m-chlorphenylhydrazon - DCMU 3-(3,4-Dichlorphenyl)-1,1-dimethylharnstoff - DNP 2,4-Dinitrophenol - DSPD Disalicylidenpropandiamin-(1,3) - PCP Pentachlorphenol - JAA Jodacetamid     

Regulatory sequences of the Sgs-4 gene of Drosophila melanogaster analysed by P element-mediated transformation

The X chromosomally located allele Sgs-4 ^c for a larval secretion protein of Drosophila melanogaster is normally expressed in female larvae of the strain Oregon R and is hyperexpressed in male larvae exhibiting dosage compensation; the allele Sgs-4 ^d in the strain Samarkand is weakly expressed and is not hyperexpressed in male larvae showing a dosage effect. P element-mediated transformation of upstream DNA sequences from both alleles combined with Sgs-4 ^d coding and downstream sequences was performed to localize sequences which are responsible for the level of gene expression and for hyperexpression of Sgs-4 ^c in male larvae. Our results demonstrate that weak expression and dosage effect are inherited with the upstream region from –1 to –838. This Samarkand fragment differs from the homologous Oregon R region only by a C to T transiion at –344 which lies within an assumed binding sequence for the ecdysone receptor complex of dyad base symmetry. Replacing the Samarkand upstream region from –1 to –838 by the Oregon R region restores normal Sgs-4 expression and dosage compensation. Hyperexpression in male larvae displays high sensitivity to position effect and is nearly completely inhibited in one transformed line under heterozygous conditions. The integration of an Sgs-4 ^d transposon into a weak spot of polytene chromosome 2L results in a decrease in gene expression. The GTT- and GT-rich regions at –1.2 and –2.0 kb do not obviously influence Sgs-4 expression but possibly play a role in induction of stage-specific chromosome puffing.     

Association behaviour of human erythrocyte phosphofructokinase. Dependence of molecular weight on enzyme concentration as analyzed by frontal gel chromatography.

Self-association of human erythrocyte phosphofructokinase has been studied at pH 8.0 and at 4 degrees C in the presence of 2 mM fructose 6-phosphate by means of frontal gel chromatography. Under these conditions the basic associating catalytically active species is the tetramer of the enzyme with a molecular weight of about 330000, the monomers of which having a molecular weight of 83000 as determined by sodium dodecyl sulphate electrophoresis. The experimental data have been compared with various models describing the enzyme association. The mode of association can sufficiently be described by assuming a weakly negative cooperative process in which the association constant of the nucleation step (association of two tetramers to an octamer) is larger than that of the following propagation steps. The geometry of association appears to be approximately spherical.     

Binding of fructose-6-phosphate to phosphofructokinase from yeast.

Yeast phosphofructokinase binds one molecule of fructose-6-phosphate per subunit. The binding curve exhibits sigmoidality and yields a good fit to an equation derived from the kinetic model as developed previously for this enzyme. The results show that the allosteric kinetic response of the enzyme to fructose-6-phosphate is due to cooperativity of the binding process.     

Empirical Bayes small area prediction under a zero-inflated lognormal model with correlated random area effects

Many variables of interest in agricultural or economical surveys have skewed distributions and can equal zero. Our data are measures of sheet and rill erosion called Revised Universal Soil Loss Equation - 2 (RUSLE2). Small area estimates of mean RUSLE2 erosion are of interest. We use a zero-inflated lognormal mixed effects model for small area estimation. The model combines a unit-level lognormal model for the positive RUSLE2 responses with a unit-level logistic mixed effects model for the binary indicator that the response is nonzero. In the Conservation Effects Assessment Project (CEAP) data, counties with a higher probability of nonzero responses also tend to have a higher mean among the positive RUSLE2 values. We capture this property of the data through an assumption that the pair of random effects for a county are correlated. We develop empirical Bayes (EB) small area predictors and a bootstrap estimator of the mean squared error (MSE). In simulations, the proposed predictor is superior to simpler alternatives. We then apply the method to construct EB predictors of mean RUSLE2 erosion for South Dakota counties. To obtain auxiliary variables for the population of cropland in South Dakota, we integrate a satellite-derived land cover map with a geographic database of soil properties. We provide an R Shiny application called viscover (available at https://lyux.shinyapps.io/viscover/ ) to visualize the overlay operations required to construct the covariates. On the basis of bootstrap estimates of the mean square error, we conclude that the EB predictors of mean RUSLE2 erosion are superior to direct estimators.     

The death of dignity is greatly exaggerated: Reflections 15 years after the declaration of dignity as a useless concept

Fifteen years ago, Ruth Macklin shook the medical community with her claim in the BMJ that dignity is a useless concept. Her essay provoked a storm of reactions. What have we learned from the debate? In this article I analyse the responses to her essay and the following debate to investigate whether she was right that “[d]ignity is a useless concept in medical ethics and can be eliminated without any loss of content.” While some of the commentaries misconstrued her claim and argue against strawmen, others forcefully maintained that the concept of dignity has functions beyond “respect for persons and their autonomy.” One important point that came out of the debate is that dignity is a generic concept that covers more ground than “respect for persons or their autonomy.” In particular, dignity seems to have a wide range of protective functions as well as having reciprocal, relational, and social aspects. Dignity appears more attributional and norm-formative than respect for persons and autonomy. While the claim that dignity is unclear, vague, and can be used sloganistically seems highly relevant, it is argued that this vagueness fulfils important functions in ethics. Moreover, dismissing dignity because of its lack of clarity has implications for “respect for persons” and “autonomy,” which are also used vaguely and sloganistically. No doubt medical ethics should use as a clear concept as the context requires. Nonetheless, dignity still seems to be a widely used generic concept in ethical debates and doing as much ethical work as “respect for persons” or “respect for autonomy.” Therefore, the death of dignity seems to be greatly exaggerated.