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The distribution and cycling of lead (Pb) was examined in an urban forest of Aleppo pine stand in Athens. Concentrations of the soluble fraction of Pb in bulk and throughfall deposition were low, reflectingthe change in petrol form in recent years. However, Pb concentrations in forest floor remain high due to Pb accumulation in previous years. The soil A horizon showed unexpectedly high levels of Pb concentration resulted probably from Pb migration from organic horizons. Pb concentrations in pine needles, litterfall and wood were low, whereas tree bark acted as a sink for Pb and stored high amounts of the metal. © Springer 2005.

The antitumor antibiotic Altromycin H was studied using electronic absorption (UV-Vis.) and circular dichroism (CD) spectroscopy. The dissociation constants of the phenolic groups on C(5) and C(11) were estimated as pK 1 = 6.7 and pK 2 = 11.8 at 25°C, respectively, and a complete assignment of the CD and UV-Vis. bands is proposed. The interaction of Cu(II) ions with the Altromycin H has been also investigated by UV-Vis., CD and electron paramagnetic resonance (EPR) spectroscopy. A pH depended stepwise complex formation was observed. At pH < 4 no copper-Altromycin H interactions were detected. At the 4 < pH < 8 the Cu(II) ions coordinate to Altromycin H via the C(4)O and C(5)OH groups atoms of the chromophore ring and the [Cu(AltroH) 2] complex (formation constant, K f, 4.00 ± 0.9 × 10 11 M -2 at 25°C) is the predominant species. In alkaline solution the hydroxo-bridged complex, [Cu(OH)(AltroH)] 2, is proposed to be as the unique present species. © 2004 Elsevier Inc. All rights reserved.

The interaction of the anticancer antibiotic altromycin B and its isostructrural Pt(II) and Pd(II) metal complexes with native calf thymus (CT) DNA was studied using UV-thermal denaturation experiments, circular dichroism spectroscopy and temperature controlled spectrophotometric titrations. Altromycin B stabilizes the double helix by raising the Tm, mainly by intercalation of its chromophore between the base pairs and interacting electrostatically via its sugar moieties with the edges of the DNA helix. Moreover, altromycin B induces a B→A structural transition of CT DNA. The effect on DNA stability and conformation depends on the metal ion. Pt(II) and Pd(II) complexes induce the B→A structural transition and stabilize the double helix similarly but they present lower final hyperchromicity due to premelting effects which were caused by intra- and interstrand crosslinking. Thus, a synergic effect of the metal ions to altromycin B-CT DNA interaction is observed in both cases. Altromycin B interacts with 5′-GMP, 5′-AMP and 5′-CMP by electrophilic attack of the opened epoxide ring to the N(7)G, N(1)/N(7)A and N(3)C. Thus, covalent binding between these nucleotides and altromycin B takes place and explain the multiple binding mode suggested by the studies of the interaction of altromycin B and its complexes with DNA. The [Pd(II)-altroB] complex dissociates in the presence of the nucleotides, and various species of Pd(II)-nucleotide complexes, especially with 5′-GMP, are formed. The [Pt(II)-altroB] complex dissociates too, but only one or two species of Pt(II)-nucleotide complexes are formed, and in the case of 5′-AMP interaction the formation of a tertiary altroB-Pt(II)-5′AMP complex is proposed. 5′-TMP reacts very weakly in comparison with the other three nucleotides. These interactions were followed by 1H-NMR. © 2003 Elsevier Science Inc. All rights reserved.

Interaction of the anticancer antibiotic altromycin B with Cu(II), Pd(II) and Pt(II) ions was studied using 1H-NMR, EPR, electronic absorption and circular dichroism spectroscopy. The results derived from NMR studies where that the Pt(II) and Pd(II) ions interact with the nitrogen atom of the dimethylamino group of the C(10)-disaccharide, while the C(2)-epoxide group does not participate and remains intact. Cu(II) ions interact in a different way with altromycin B as was concluded by EPR and circular dichroism spectra. Altromycin B coordinates to the Cu(II) ions via the oxygen atoms of the C(11) phenolic and the C(12) carbonyl group while the nitrogen atom does not participate in the complexation. The presence of these metal ions improves the stability of altromycin B in solution. These complexes were studied in vitro against K562 leukemia sensitive and doxorubicin-resistant cells and GLC4 lung tumor cells, sensitive and doxorubicin-resistant. The activity of the complexes compared to the free drug is improved against resistant cells and is affected moderately against sensitive cells. Finally, 20% of platinum added as altromycin B metal complex entered GLC4 cells. Copyright © 2001 Elsevier Science Inc.