Use of a fluorescence-based approach to assess short-term responses of the alga Pseudokirchneriella subcapitata to metal stress

This work explores the use of fluorescent probes to evaluate the responses of the green alga Pseudokirchneriella subcapitata to the action of three nominal concentrations of Cd(II), Cr(VI), Cu(II) and Zn(II) for a short time (6 h). The toxic effect of the metals on algal cells was monitored using the fluorochromes SYTOX Green (SG, membrane integrity), fluorescein diacetate (FDA, esterase activity) and rhodamine 123 (Rh123, mitochondrial membrane potential). The impact of metals on chlorophyll a (Chl a) autofluorescence was also evaluated. Esterase activity was the most sensitive parameter. At the concentrations studied, all metals induced the loss of esterase activity. SG could be used to effectively detect the loss of membrane integrity in algal cells exposed to 0.32 or 1.3 mol L1 Cu(II). Rh123 revealed a decrease in the mitochondrial membrane potential of algal cells exposed to 0.32 and 1.3 mol L1 Cu(II), indicating that mitochondrial activity was compromised. Chl a autofluorescence was also affected by the presence of Cr(VI) and Cu(II), suggesting perturbation of photosynthesis. In conclusion, the fluorescence-based approach was useful for detecting the disturbance of specific cellular characteristics. Fluorescent probes are a useful diagnostic tool for the assessment of the impact of toxicants on specific targets of P. subcapitata algal cells.The authors thank the FCT Strategic Project PEst-OE/EQB/LA0023/2013. Manuela D. Machado gratefully acknowledges the post-doctoral grant from FCT (SFRH/BPD/72816/2010)

The first examples of isonitrile insertion into a phosphido bridge and the crystal and molecular structures of [Pt2(mu-P(t)Bu2){mu,eta2-P(t)Bu-2)C(=NAr)}(CNAr)2] and [Pt{mu,eta2-P(t)Bu-2)C (NHAr)}(CNAr)]2(CF3SO3)2 (Ar = p-tolyl)

The platinum(I) dinuclear carbonyl [Pt-2(mu -PBu2t)(2)((PBu2H)-H-t)(CO)] (1) reacts with organic isonitriles RNC (R = p-tolyl, Bu-t, PhCH2), yielding the mono- and disubstituted derivatives [Pt-2(mu -PBu2t)(2)((PBu2H)-H-t)(CNR)] (2, R = p-tolyl; 3, R = Bu-t; 4, R = PhCH2) and [Pt(mu -PBu2t)(CNR)](2) (5, R = p-tolyl; 6, R = Bu-t; 7, R = PhCH2). Only with the aromatic isonitrile does the reaction proceed through two further well-separated steps, giving [Pt-2(mu -PBu2t){mu,eta (2)-P(Bu-2(t))C(=NAr)}(CNAr)(2)] (8) and [Pt{mu,eta (2)-P(Bu-2(t))C(=NAr)}(CNAr)](2) (9). These arise from the unprecedented reversible isonitrile insertion into the M-P bonds of the phosphido-bridges. When 8 or 9 are reacted with CF3SO3H, the cyclic carbenes [Pt-2(mu -PBu2t){mu,eta (2)-P(Bu-2(t))C(NHAr)}(CNAr)(2)]CF3SO3 (10) and [Pt{mu,eta (2)-P(Bu-2(t))C(NHAr)}(CNAr)](2) (CF3SO3)(2) (11) are respectively formed. The crystal and molecular structures of complexes 8 and 11 were solved by X-ray diffraction

The first examples of isonitrile insertion into a phosphido bridge and the crystal and molecular structures of [Pt-2(mu-PBu2t){mu,eta(2)-P(Bu-2(t))C(=NAr)}(CNAr)(2)] and [Pt{mu,eta(2)-P(Bu-2(t))C (NHAr)}(CNAr)](2)(CF3SO3)(2) (Ar = p-tolyl)

The platinum(I) dinuclear carbonyl [Pt-2(mu -PBu2t)(2)((PBu2H)-H-t)(CO)] (1) reacts with organic isonitriles RNC (R = p-tolyl, Bu-t, PhCH2), yielding the mono- and disubstituted derivatives [Pt-2(mu -PBu2t)(2)((PBu2H)-H-t)(CNR)] (2, R = p-tolyl; 3, R = Bu-t; 4, R = PhCH2) and [Pt(mu -PBu2t)(CNR)](2) (5, R = p-tolyl; 6, R = Bu-t; 7, R = PhCH2). Only with the aromatic isonitrile does the reaction proceed through two further well-separated steps, giving [Pt-2(mu -PBu2t){mu,eta (2)-P(Bu-2(t))C(=NAr)}(CNAr)(2)] (8) and [Pt{mu,eta (2)-P(Bu-2(t))C(=NAr)}(CNAr)](2) (9). These arise from the unprecedented reversible isonitrile insertion into the M-P bonds of the phosphido-bridges. When 8 or 9 are reacted with CF3SO3H, the cyclic carbenes [Pt-2(mu -PBu2t){mu,eta (2)-P(Bu-2(t))C(NHAr)}(CNAr)(2)]CF3SO3 (10) and [Pt{mu,eta (2)-P(Bu-2(t))C(NHAr)}(CNAr)](2) (CF3SO3)(2) (11) are respectively formed. The crystal and molecular structures of complexes 8 and 11 were solved by X-ray diffraction

An Experimental and Theoretical Study of the Electronic and Molecular Structure of [Zn4(\u3bc4-S){\u3bc-S2P(OC2H5)(2)}(6)]: the First Molecular Model of ZnS

The electronic and molecular structure of hexakis[\u3bc-(O,O\u2032-diethyl dithiophosphate-S:S\u2032)]-\u3bc4-thiotetrazinc, [Zn4(\u3bc4-S){\u3bc-S2P(OC2H5)2}6] (1), has been investigated by combining X-ray diffraction measurements, UV\u2013vis absorption spectroscopy and density functional calculations. The title compound is characterized by a Zn4(\u3bc4-S)(\u3bc-S12) core consisting of a S atom at the center of a distorted tetrahedron of Zn ions, each of them placed at the center of an irregular tetrahedron of S atoms. Theoretical results point out that 1, at variance to the isostructural [Zn4(\u3bc4-S){\u3bc-S2As(CH3)2}6] recently investigated by Albinati et al. [Inorg. Chem. 38 (1999) 1145], can be considered a well tailored molecular model of ZnS. Theoretical outcomes also indicate that the low energy region of the UV absorption spectrum of 1 includes transitions having a ligand-to-metal-charge transfer nature involving the excitation of an electron from the occupied \u3bc4-S 3p based atomic orbitals to the empty Zn 4s based levels

Funkenerosive Senkbearbeitung mit hohen Entladeenergien - Entwicklung eines hygienisch-toxikologischen Bewertungs- und Ueberwachungskonzepts, Entwicklung einer Emissionsminderungstechnologie Abschlussbericht

Available from TIB Hannover: F03B1421 / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDeutsche Bundesstiftung Umwelt, Osnabrueck (Germany)DEGerman