Elevated levels of plasma lipofuscins in patients with chronic renal failure

The fluorescence excitation and emission spectra observed in plasma from patients with chronic renal failure were reproduced by the generation of soluble lipofuscins in normal plasma samples by incubation with mixtures of L-dopa, dopamine, L-norepinephrine, L-epinephrine, 3-hydroxy-DL-kynurenine and 3-hydroxy-anthranilic acid for 24 h at 37 degrees C. Relative fluorescence intensity measurements consistently showed elevated plasma levels of the soluble lipofuscins in chronic renal failure: the means (n = 27) were 73.9 +/- 33.4 (SD) and 71.1 +/- 14.8 at emissions 413 nm and 445 nm respectively, in contrast to those of normal plasma samples (n = 11), 18.2 +/- 5.3 and 23.1 +/- 5.6. The maximum or shoulder at approximately 413 nm represents soluble lipofuscin that can be generated from 3-hydroxyanthranilic acid and the maximum or shoulder at approximately 445 nm represents soluble lipofuscins derived from the precursors listed above and probably from other related precursors. Gravimetric measurements also showed elevated levels of melanins in the plasma samples of patients with chronic renal failure: 2.72 +/- 0.38 mg/ml (n = 16), as compared to normal values: 1.70 +/- 0.10 mg/ml (n = 6). In individual patients haemodialysis reduced the fluorescence intensities to a range of 65-99% and the melanin levels to a range of 86-99% of the pre-dialysis values.     

The genetics and expression of an esterase locus inAnopheles gambiae

The main polymorphic system of esterase isoenzymes in adults of the G3 laboratory strain ofAnopheles gambiae consists of two to five major bands of activity per individual. The bands are designated 5S, 5F, 13, 14, and 15. In genetic crosses, the genes which coded for the bands assorted as three codominant alleles, Est A, Est B, and Est C, at a single autosomal locus. Homozygotes for the Est C allele were significantly underrepresented among backcross progeny. The developmental pattern of esterase expression was examined. Esterase gene expression in embryos was first detectable between 2 and 12 hr after oviposition. The initiation or termination of expression of some of the bands corresponded to boundaries between developmental stages. Most of the esterase fractions were not specifically localized within the tissues tested, with the exception of a series of bands which were restricted largely to adult male testes.     

Heterogeneity of Lethals in a "Simple" Lethal Complementation Group

Of 24 ethyl methanesulphonate-induced, recessive-lethal mutations in the region 9E1-9F13 of the X chromosome of Drosophila melanogaster, eight fall into a typically homogeneous lethal complementation group associated with the raspberry (ras) locus. Mutations in this group have previously been shown to be pleiotropic, affecting not only ras but also two other genetic entities, gua 1 and pur 1, which yield auxotrophic mutations.--The eight new mutations have been characterized phenotypically in double heterozygotes with gua 1, pur 1 and ras mutations. Despite their homogeneity in lethal complementation tests, the mutations prove quite diverse. For example, two mutations have little or no effect on eye color in double heterozygotes with ras2. The differences between the lethals are allele-specific and cannot be explained as a trivial outcome of a hypomorphic series.--Taken alone, the lethal complementation studies mask the complexity of the locus and the diversity of its recessive lethal alleles. By extension, we argue that the general use of lethal saturation studies provides an unduly simplified image of genetic organization. We suggest that the reason why recessive lethal mutations rarely present complex complementation patterns is that complex loci tend to produce mutations that affect several subfunctions.     

Proceedings of the fifty-fourth Annual Meeting of the American Association of physical anthropologists to be held in Knoxville,Tennessee—Holiday Inn World's fair April 10–13, 1985

Empirical analyses and models of the lineal effects of fission indicate that considerable genetic differentiation may occur at the time of group formation, thus confusing the usual positive relationship between historical affiliation and genetic differentiation. We analyze the effects of fission pattern on variation in highly heritable morphological traits among eight social groups on Cayo Santiago. The analysis is performed using general network autocorrelation methods that quantitatively and directly measure the amount of variation in social group mean morphology that can be explained by fission. All of the fission autocorrelation coefficients are strongly negative, indicating that groups most recently formed by fission are most dissimilar. Also, most of the variation between groups can be explained by the fission pattern, indicating that lineal fission is the most important process generating between-group variation on Cayo Santiago.     

Spin probe clustering in human erythrocyte ghosts

Summary A model has been developed for 5-nitroxide stearate, I(12,3), distribution in human erythrocyte ghosts which accurately predicts ESR spectral alterations observed with increased probe/total lipid (P/L) at 37°C. This spin probe occupies a class of high-affinity, noninteracting sites at low loading. Saturation occurs with increasing probe concentration, and, at higher loading, the probe inserts itself at initially dilute sites to form membranebound clusters of variable size. No low probe remains at high P/L where all I(12,3) clusters in a concentrated phase. This model allows determination of the dilute/clustered probe ratio, and shows that I(12,3) segregates in erythrocytes at what might otherwise be considered low P/L (e.g., 1/359). These findings validate the earlier use of empirical parameters to estimate probe sequestration in biological membranes.     

Thigmomorphogenesis: The induction of callose formation and ethylene evolution by mechanical perturbation in bean stems

Mechanical perturbation by rubbing of the first internode of 11–12 day old plants of Phaseolus vulgaris L. cv. Cherokee wax induces the rapid deposition of callose in the cells of phloem and other tissues. Callose deposition begins immediately after mechanical perturbation, and shows a minor transient peak 1.5 h, and a major peak 6 h later. The callose gradually disappears and is gone after 3 days. If the stems are perturbed every day, the amount of callose decreases by day 2 but then gradually increases again through day 12. Both the top and bottom of the internode produce callose in response to mechanical perturbation. The evolution of ethylene in response to mechanical perturbation begins after 1 h, peaks at 2–3 h and is gone by 5–6 h. A spray of 10⁻² M 2-deoxy-D-glucose (DDG) completely blocks stem thickening, callose deposition and ethylene evolution due to mechanical perturbation. DDG at 10⁻⁵ to 10⁻⁴ M blocks callose production in mechanically perturbed stem segments and increases ethylene evolution from unperturbed stem segments to greater levels than those obtained by mechanically perturbed segments. It is concluded that mechanical perturbation of bean stems tissue induces deposition of callose more rapidly than it induces evolution of ethylene and that DDG can block both processes.     

Computer-Assisted Image Analysis of Plant Growth, Thigmomorphogenesis, and Gravitropism

A nonintrusive auxonometric system, based on the DARWIN image processor (Telewski et al. 1983 Plant Physiol 72: 177-181), is described and demonstrated in the analysis of gravitropism and thigmomorphogenesis in corn seedlings (Zea mays). Using this system, growth and bending of regularly shaped plants or organs can be quickly and accurately measured without, in any way, interfering with the plant. Furthermore, the growth and bending curves are automatically plotted. Thigmomorphogenesis in the aerial part of corn seedlings involves growth promotion at a low force load and growth retardation at higher force loads. The time courses of the two kinds of response are somewhat different, with retardation occurring immeditely after mechanical perturbation and growth promotion taking somewhat longer to begin. Gravitropic experiments show that when dark-grown corn seedlings are placed on their side in the light, the resulting curvature is due to two consecutive morphological mechanisms. In the first instance, lasting for about 15 minutes, the elongation of the bottom edge of the plant accelerates, while the elongation of the top edge remains constant. After that, for the next 1.75 hours, the elongation of the top edge decelerates and stops while that of the bottom edge remains constant at the increased rate for most of the period. The measurements taken from both experiments at relatively high resolution (0.08-0.1 millimeter) show that the growth curves are not smooth but show many small irregularities which may or may not involve micronutations.     

Green-backed herons (Butorides striatus) possibly using a lure and using apparent bait

Zusammenfassung In Burkina Faso ließ ein Mangrovereiher offensichtlich gezielt eine Asclepiadaceen-Blüte aus 20 cm Höhe auf die Wasseroberfläche fallen und verharrte danach einige Sekunden mit halb-gestrecktem Hals. Bei einer weiteren Beobachtung in Niger plazierte ein Mangrovereiher einen kleinen Gegenstand auf der Wasseroberfläche. Bevor der Gegenstand mit dem Wind außer Reichweite trieb, holte ihn der Reiher und legte ihn auf der Luvseite wieder auf der Wasseroberfläche ab. Der Vorgang wiederholte sich mehrere Male, dabei gelang es dem Reiher, einen Fisch zu erbeuten, der allerdings wieder entkam. Anderntags setzte an derselben Stelle ein Mangrovereiher in gleicher Weise offensichtlich einen Käfer ein. Ähnliche Beobachtungen werden kurz diskutiert.     

A selenomethionine-containing azurin from an auxotroph of Pseudomonas aeruginosa

The production and spectroscopic properties of an L-selenomethionine-containing homolog of Pseudomonas aeruginosa azurin are described. The amino acid substitution was carried out by developing an L-methionine-dependent bacterial strain from a fully functional ATCC culture. Uptake studies monitored using L-[75Se]methionine indicated that L-selenomethionine was incorporated into the protein synthetic pathway of Pseudomonas bacteria in a manner analogous to L-methionine. Several batches of bacteria were grown, and one sample of isolated and purified selenoazurin (azurin in which methionine was substituted by selenomethionine) was found (by neutron activation analysis) to contain 5.2 +/- 0.8 seleniums/copper. Correspondingly, a residual 0.35 methionines, relative to 6.0 in the native protein, were found by amino acid analysis in this azurin sample. The redox potential and extinction coefficient of this selenoazurin were found to be 333 +/- 1 mV (pH 7.0, I = 0.22) and 5855 +/- 160 M-1 cm-1 at 626 +/- 1 nm, respectively. Visible electronic, CD, and EPR spectra are reported and Gaussian curve fitting to the former spectrum allowed assignment of the selenomethionine Se----Cu(II) transition to a band found at 18034 cm-1, based upon an observed 450 cm-1 shift to the red from the analogous band position in the native protein. The data are consistent with a relatively more covalent copper site stabilizing the reduced, Cu(I), form in the selenoprotein. A role for the methionine as a modulator of the blue copper site redox potential by metal----ligand back bonding from Cu(I) is discussed in terms of a ligand sphere which limits the valence change at copper to much less than 1 during a redox cycle.