Manfred Niecke

ElaC Encodes a Novel Binuclear Zinc Phosphodiesterase

ElaC is a widespread gene found in eubacteria, archaebacteria, and mammals with a highly conserved sequence. Two human ElaC variants were recently associated with cancer (Tavtigian, S. V., Simard, J., Teng, D. H., Abtin, V., Baumgard, M., Beck, A., Camp, N. J., Carillo, A. R., Chen, Y., Dayananth, P., Desrochers, M., Dumont, M., Farnham, J. M., Frank, D., Frye, C., Ghaffari, S., Gupte, J. S., Hu, R., Iliev, D., Janecki, T., Kort, E. N., Laity, K. E., Leavitt, A., Leblanc, G., McArthur-Morrison, J., Pederson, A., Penn, B., Peterson, K. T., Reid, J. E., Richards, S., Schroeder, M., Smith, R., Snyder, S. C., Swedlund, B., Swensen, J., Thomas, A., Tranchant, M., Woodland, A. M., Labrie, F., Skolnick, M. H., Neuhausen, S., Rommens, J., and Cannon-Albright, L. A. (2001) Nat. Genet. 27, 172–180; Yanaihara, N., Kohno, T., Takakura, S., Takei, K., Otsuka, A., Sunaga, N., Takahashi, M., Yamazaki, M., Tashiro, H., Fukuzumi, Y., Fujimori, Y., Hagiwara, K., Tanaka, T., and Yokota, J. (2001)Genomics 72, 169–179). Analysis of the primary sequence indicates homology to an arylsulfatase and predicts a metallo-β-lactamase fold. At present, no ElaC gene product has been investigated. We cloned the Escherichia coli ElaC gene and purified the recombinant gene product. An enzymatic analysis showed that ElaC does not encode an arylsulfatase but rather encodes a phosphodiesterase that hydrolyzes bis(p-nitrophenyl)phosphate with ak cat of 59 s−1 and K′ of 4 mm. Kinetic analysis of the dimeric enzyme revealed positive cooperativity for the substrate bis(p-nitrophenyl)phosphate with a Hill coefficient of 1.6, whereas hydrolysis of the substrate thymidine-5′-p-nitrophenyl phosphate followed Michaelis-Menten kinetics. Furthermore, the enzyme is capable of binding two zinc or two iron ions. However, it displays phosphodiesterase activity only in the zinc form. The metal environment characterized by zinc K-edge x-ray absorption spectroscopy was modeled with two histidine residues, one carboxylate group, and 1.5 oxygen atoms. This corresponds to the coordination found in other metallo-β-lactamase domain proteins. Phosphodiesterase activity is strongly dependent on the presence of zinc. These results identify the currently unassigned gene product ElaC to be a novel binuclear zinc phosphodiesterase.

Effects of strontium ranelate administration on bisphosphonate-altered hydroxyapatite: Matrix incorporation of strontium is accompanied by changes in mineralization and microstructure

Strontium ranelate (SR) is one therapeutic option for reducing risk of fracture in osteoporosis. The effects of SR treatment on hydroxyapatite (HA) previously altered by bisphosphonate (BP) administration remain to be established. Patients who have received long-term BP treatment and present with persistent high fracture risk are of particular interest. Paired iliac crest biopsies from 15 patients post-BP therapy were subjected to a baseline biopsy and a follow-up biopsy after treatment with 2g SR day⁻¹ after either 6 months (n=5) or 12 months (n=10). Dual energy X-ray absorptiometry scans, serum parameters and biochemical markers were obtained. Quantitative backscattered electron imaging and energy-dispersive X-ray analyses combined with micro-X-ray fluorescence determinations were performed to observe any mineralization changes. Static 2-D histomorphometry was carried out to evaluate cellular and structural indices. After 6 months of SR treatment, increases in osteoid surface and strontium content were observed, but no other indices showed significant change. After 12 months of SR treatment, there was a significant increase in bone volume and trabecular thickness, and further increases in strontium content and backscattered signal intensity. These structural changes were accompanied by increased numbers of osteoblasts and increased osteoid surface and volume. Additionally, low bone resorption, as measured by beta-cross-laps, and a low number of osteoclasts were observed. SR treatment led to increased strontium content within the BP-HA nanocomposites and to increased osteoid indices and bone volume, which is indicative of newly formed bone, while osteoclasts were still suppressed. These data points suggest that SR might be considered as a therapeutic option for patients following long-term BP treatment.

Why do melanin ornaments signal individual quality? Insights from metal element analysis of barn owl feathers

Melanin-based variation in colour patterns is under strong genetic control and not, or weakly, sensitive to the environment and body condition. Current signalling theory predicts that such traits may not signal honestly phenotypic quality because their production does not entail a significant fitness cost. However, recent studies revealed that in several bird species melanin-based traits covary with phenotypic attributes. In a first move to understand whether such covariations have a physiological basis, we quantified concentrations of five chemical elements in two pigmented plumage traits in the barn owl (Tyto alba). This bird shows continuous variation from immaculate to heavily marked with black spots (plumage spottiness) and from dark reddish-brown to white (plumage coloration), two traits that signal various aspects of individual quality. These two traits are sexually dimorphic with females being spottier and darker coloured than males. We found an enhancement in calcium and zinc concentration within black spots compared with the unspotted feather parts. The degree to which birds were spotted was positively correlated with calcium concentration within spots, whereas the unspotted feather parts of darker reddish-brown birds were more concentrated in zinc. This suggests that two different pigments are responsible for plumage spottiness and plumage coloration. We discuss the implications of our results in light of recent experimental field studies showing that female spottiness signals offspring humoral response towards an artificially administrated antigen, parasite resistance and fluctuating asymmetry of wing feathers.

Correlations between melanin pigmentation and element concentration in feathers of White-tailed Eagles (Haliaeetus albicilla)

The element concentration of moult feathers of White-tailed Eagles was investigated. Using the 2- MeV Hamburg proton microprobe we tried to differentiate between elements incorporated into the feather via the food chain and those which are deposited externally onto the feather vane. Regarding incorporated elements, special attention has been given to a possible correlation between element concentration and feather pigmentation. Concerning the elements detected in this work (S, K, Ca, Ti, Mn, Fe, Cu, Zn, Hg, Pb), calcium, manganese and zinc show a considerable enhancement within the pigmented feather as compared with pigment-free feather sections. On the other hand, no differences were found in concentrations for sulfur, titanium, iron, copper, mercury and lead. Our findings therefore imply a special enrichment of Ca, Mn and Zn within melanin, the source of the feathers pigmentation. The possible role of these elements with regard to melanin formation is discussed. Es wurden die Elementkonzentrationen in Mauserfedern von Seeadlern untersucht. Mit Hilfe der Hamburger 2-MeV-Protonenmikrosonde, die die Analyse von Probendetails im Mikrometerbereich ermöglicht, versuchen wir zwischen Elementen zu unterscheiden, die vom Adler mit der Nahrung inkorporiert, verstoffwechselt und während der Mauser in die Feder eingelagert wurden und solchen, die während der etwa einjährigen Verweilzeit der Feder im Gefieder extern aus der Atmosphäre aufgelagert wurden. Im Hinblick auf die eingelagerten Elemente untersuchen wir mögliche Zusammenhänge zwischen der Elementkonzentration und der Federpigmentierung. Von den nachgewiesenen Elementen (Schwefel, Kalium, Calcium, Titan, Mangan, Eisen, Kupfer, Zink, Quecksilber und Blei) zeigen Calcium, Mangan und Zink eine erhebliche Anreicherung in der pigmentierten Feder im Vergleich zu pigmentfreien Federausschnitten. Dagegen wurden keine signifikanten Unterschiede der Elementkonzentrationen von Schwefel, Titan, Eisen, Kupfer, Quecksilber und Blei festgestellt. Die gefundenen Ergebnisse bedeuten eine erhebliche Anreicherung von Calcium, Mangan und Zink im Melanin, das für die Federpigmentierung verantwortlich ist. Die mögliche Funktion dieser Elemente im Hinblick auf die Melaninbildung wird diskutiert.

Micro-PIXE studies of elemental distribution in Cd-accumulating Brassica juncea L.

Abstract Brassica juncea L. is a high biomass producing crop plant, being able to accumulate Cd and other heavy metals in their roots and shoots. It is a good candidate for efficient phytoextraction of heavy metals – such as Cd – from polluted soils. PIXE and STIM analyses were applied to investigate Cd-uptake in roots and the resulting effects on the elemental distribution of Cd stressed plants. The axial distribution of trace elements as a function of distance from the root tip as well as the radial distribution within cross-sections were analysed. The results are compared with the elemental distribution in control plants.

Allocation of nonbirefringent wear debris: Darkfield illumination associated with PIXE microanalysis reveals cobalt deposition in mineralized bone matrix adjacent to CoCr implants

Abrasive joint replacement material that accumulates in the tissue induces reciprocal effects between prosthesis material and organism. Since the limitations of brightfield and polarized light microscopy for foreign body analysis are well known, a method was applied that ensures the detailed histological assessment of nonbirefringent particles in periprosthetic soft and hard tissue. Cemented and cementless interface regions of five selected autopsy hip implant cases (2 x Endo-Modell Mark III, LINK, 1 x St. Georg Mark II, LINK, Germany; 2 x Spongiosa Metal II, ESKA, Germany) were viewed under darkfield illumination and subsequently analyzed with proton-induced X-ray emission (PIXE). Eight autopsy cases without implants served as controls. Using darkfield illumination technique, metallic particles became visible as luminous points under the microscope. The majority of particles in the samples from the cemented cases were degradation products of radiopaque bone cement. There was minimal evidence of metallic alloy particles in the soft tissues. However, a considerable quantity of heavy metal cobalt (Co) was found in the periprosthetic mineralized bone tissue, which was not observed in the controls. The periprosthetic concentration of cobalt ranged from 38 to 413 ppm. The findings demonstrate a correlation between cobalt concentration, time since implantation, and distance from the implant. Darkfield microscopy associated with PIXE enables a detailed histological assessment of metal particles in the tissue. In an effort to optimize biomechanics, implant design and implantation techniques, the contamination of soft and hard tissue with heavy metal degradation products deserves similar attention in terms of alloy assortment.

The hamburg proton microprobe: Application in environmental analysis

Abstract The Hamburg proton microprobe was used to investigate the distribution of trace elements in solidified mud from the Hamburg harbour. Therefore highly contaminated mud. separated from dredged sludge, was dewatered and solidified by addition of chemical agents. A chemical extraction procedure applied before and after stabilization showed an increase of the bonding strengths of the heavy metals; however, it was unexplained whether the increase depended partly on the active incorporation of the trace elements into new and recrystalized minerals. PIXE measurements proved that an incorporation of heavy metals into mineral phases formed during the solidification process has taken place.

Vogelfedern als Biomonitoren für die atmosphärische Schwermetallbelastung — Untersuchungen mit der Protonenmikrosonde

ZusammenfassungDie Schwermetallbelastung von Elsternfedern (Pica pica L.) aus der Umgebung von Hamburg wird untersucht. Ziel dieser Arbeit ist es, zu entscheiden, in welchem Ausmaß die gemessenen Verunreinigungen auf der Federoberfläche abgelagert wurden. Ein weiterer Anteil der Schwermetalle wird möglicherweise vom Organismus aufgenommen und nach Verstoffwechselung in die Feder integriert.Mit der Protoneninduzierten Röntgenemission (PIXE) analysieren wir Teile von Federn, die lange (ca.1 Jahr), kurz (einige Tage) oder überhaupt nicht atmosphärischen Stäuben ausgesetzt waren.Außerdem untersuchen wir, in welchem Ausmaß der Schwermetallgehalt der Federn durch verschiedene Waschprozeduren verringert werden kann. Die Ergebnisse zeigen, daß der größte Anteil der Verunreinigungen der Federoberfläche fest anhaftet.Wir ziehen daraus den Schluß, daß es bei der Benutzung von Elsternfedern als Biomonitoren mit der Methode der PIXE-Analytik sinnvoller ist, die Schwermetallmasse auf die Federfläche zu beziehen und nicht—wie es bisher üblich war—auf die Federmasse.

Angular distributions of neutron polarization from the 14C(p, n)14N and 11B(α, n)14N reactions and R-matrix analysis oF 15N in the excitation-energy range between 11.5 and 12.5 MeV

Abstract Angular distributions of neutron polarization from the 14 C(p, n) 14 N and 11 B(α, n) 14 N reactions have been studied for the particle energies E p = 1.788, 2.025, 2.272 and 2.450 MeV, and E α = 2.049 MeV. The polarization was derived from the left-right asymmetry induced by elastic scattering from 4 He. Together with existing measurements of angular distributions and total cross sections for several reaction channels leading to 15 N with an excitation energy between 11.5 and 12.5 MeV, these data were used to deduce from R -matrix analysis a set of resonance parameters for the 15 N levels in this energy range.

Analyse von Quecksilber in Seeadlerfedern aus Mecklenburg-Vorpommern mit Hilfe der Hamburger Protonenmikrosonde

ZusammenfassungMit der Hamburger Protonenmikrosonde untersuchen wir den Quecksilbergehalt in Seeadlerfedern, die in Mecklenburg-Vorpommern über Jahrzehnte gesammelt wurden. Anhand der Fundorte und Funddaten ist es möglich, ein zeitliches und regional differenziertes Bild der Quecksilberbelastung, die vorwiegend durch Hg-halrige Saargutbeizen in der Landwirtschaft verursacht wurden, zu erstellen. Wir vergleichen die gefundenen Konzentrationen mit der ‘geogenen’ Grundbelastung, die an Federproben des vorigen Jahrhunderts von Museumstieren ermittelt wurde.AbstractWith the aid of the Hamburg proton micro-probe, we examined the concentration of mercury in sea eagle feathers collected over the course of several decades in the Mecklenburg-Vorpommern area. Based on the sites where these feathers were collected and the data of these findings, it is possible to get a differential picture of mercury contamination related both temporally and regionally to the mercurial pollution of seed mordants used agriculturally. We compared the concentrations found with a basic “geogenic” contamination which was also to be seen in the feather samples from the last century as detected in museum animal specimens.