Search results for "Toxicity"

Modulation of immune parameters of roach, Rutilus rutilus, exposed to untreated ECF and TCF bleached pulp effluents

2000

Abstract The present study was designed to assess the effects of elemental chlorine free (ECF) and totally chlorine free (TCF) pulp and paper mill effluents on the immune defence of the roach ( Rutilus rutilus ). Fish were exposed for 5 weeks to concentrations of 0, 0.6, 2, 6 and 20% of untreated effluents from ECF or TCF bleaching processes. In order to study the capability to respond to foreign antigens the fish were immunised with bovine γ-globulin (BGG) 3 weeks before sampling. The numbers of anti-BGG antibody-secreting cells and immunoglobulin-secreting cells in the spleen and blood, as well as the levels of the anti-BGG antibodies and concentrations of immunoglobulin in plasma and the…

Acute toxicity of several pesticides to rotifer (Brachionus calyciflorus).

1992

Hydroquinone derivatives from the marine-derived fungus Gliomastix sp.

2017

Eight new hydroquinone derivatives, gliomastins A–D (1–4), 9-O-methylgliomastin C (5), acremonin A 1-O-β-D-glucopyranoside (6), gliomastin E 1-O-β-D-glucopyranoside (7), and 6′-O-acetyl-isohomoarbutin (8), together with seven known analogues were isolated from the marine-derived fungus Gliomastix sp. Their structures were elucidated by extensive spectroscopic analysis including 1D and 2D NMR measurements aided by DFT NMR calculations as well as MS data. TDDFT-ECD and OR calculations were performed to determine the absolute configurations of 1 and the aglycones of 6 and 7. Compound 1 features a novel skeleton, biogenetically derived from a Diels–Alder reaction between derivatives of 11 and 1…

Release of Inflammatory Mediators (PGE2, IL-6) by Fenofibric Acid-Photosensitized Human Keratinocytes and Fibroblasts

1998

Ultraviolet-A radiation has weak effects on the release of inflammatory mediators by skin cells due to the poor overlap between UVA wavelengths and the absorption spectra of the relevant chromophores of key biomole-cules. However, this situation could be very different in the presence of a photosensitizing drug. To investigate this issue, we have irradiated human skin cells (keratinocytes and fibroblasts) in the presence of fenofibric acid (the active phototoxic metabolite of fenofibrate). The results of this research show a dual effect on the production/release of inflammatory mediators: the synthesis of the proinflammatory cytokine interleukin-6 becomes strongly inhibited at photosensitiz…

Ophiobolin Sesterterpenoids and Pyrrolidine Alkaloids from the Sponge-Derived Fungus Aspergillus ustus

2011

Chemical examination of the fungus Aspergillus ustus isolated from the Mediterranean sponge Suberites domuncula yielded the five new ophiobolin-type sesterterpenoids 1–5 and the two new pyrrolidine alkaloids 6 and 7, together with the known compound aurantiamine and cerebroside D. The structures of the new compounds were unambiguously elucidated on the basis of extensive spectroscopic-data analysis (1D- and 2D-NMR, MS, and UV) and comparison with literature data. All compounds were evaluated for their cytotoxicity against murine lymphoma cell line L5178Y.

Cytotoxicity of fagaramide derivative and canthin-6-one from Zanthoxylum (Rutaceae) species against multidrug resistant leukemia cells

2019

In our continuous search for cytotoxic compounds from the genus Zanthoxylum, chromatographic separation of the MeOH/CH2Cl2 (1:1) extract of Z. chalybeum yielded one new alkamide; 4-(isoprenyloxy)-3-methoxy-3,4-deoxymethylenedioxyfagaramide (1) and a known one; fagaramide (2). Similarly, from the MeOH/CH2Cl2 (1:1) extract of the stem bark of Z. parachanthum four known compounds; canthin-6-one (3), dihydrochelerythrine (4), lupeol (5) and sesamin (6) were isolated. Characterization of the structures of these compounds was achieved using spectroscopic techniques (NMR and MS). Using resazurin reduction assay 1, 3 and 6 displayed moderate cytotoxicity with IC50 values below 50 μM against the dru…

Association of Marginal Leaf Scorch with Sodium Accumulation in Salt-stressed Peach

2000

The effect of specific ion toxicity during salt stress was tested in the present study. The experiment was repeated twice, in 1996 and 1998, with `Nemaguard' peach seedlings and rooted cuttings grown in hydroponics under two NaCl concentrations (50 and 30 mm). Foliage was separated in symptomatic and symptomless leaves and the amount of sodium (Na+) and chloride (C1–) was determined. Significantly higher Na+ content was found in symptomatic than in symptomless leaves in both experiments, whereas in only two of the six cases was Cl– content higher in symptomatic than in symptomless leaves. The Na+ threshold for leaf scorch was somewhere between 4 and 6 mg·g–1 dry weight. Results indicated th…

Ecotoxicological studies with the freshwater rotifer Brachionus calyciflorus II. An assessment of the chronic toxicity of lindane and 3,4-dichloroani…

1993

The effects of chronic exposure of the freshwater rotifer Brachionus calyciflorus to the toxicants lindane and 3,4-dichloroaniline (DCA), were evaluated. The parameters used to determine the toxicity on these compounds were the age-specific and fertility, and the demographic parameters: intrinsic rate of natural increase (r), generation time (T), net reproductive rate (Ro), reproductive value (Vx) and life expectancy (eo). All the demographic parameters studied decreased with increasing toxicant concentrations. The use of life tables techniques with B. calyciflorus as a test method for the determination of chronic toxicity of xenobiotics is discussed.

Squaraine Dyes for Photodynamic Therapy: Mechanism of Cytotoxicity and DNA Damage Induced by Halogenated Squaraine Dyes Plus Light (>600 nm)¶

2004

Halogenated squaraine dyes 1 and 2 possess favorable photophysical and in vitro photobiological properties that make these new class of molecules interesting for photodynamic therapeutic applications. For a better understanding of the mechanism of their photobiological activity, we have analyzed the DNA damage and the cytotoxicity induced by these photosensitizers in mammalian cells and cell-free systems in the presence and absence of various additives and scavengers. Both photoactivated squaraines were found to be similar efficient in inducing single-strand breaks (SSB) in cell-free DNA when compared with the cellular DNA. Superoxide dismutase and catalase did not show any influence. Howev…

Organometallic complexes with biological molecues, part 3.in vivo cytotoxicity of diorganotin (IV) chloro and triorganotin (IV) chloro derivatives of…

1994

In order to obtain a continuous source of mitotic metaphases, gill tissue of Aphaius fasciatus (Pisces, Cyprinodontiformes) has been successfully employed. Results gathered after exposure of fish to R2SnClpenG, R3SnClpenGNa, to the parents R2SnCl2, R3SnCl and to penGNa (penGNa = penicillinGNa; R = methyl, butyl and phenyl) suggest that both the parent organotin (IV) chloride and organotin (IV) chloropenG derivatives are toxic while penGNa exerts no significant toxic activity. Essentially, all of the chromosome abnormalities are classifiable as irregularly staining of chromosomes, breakages, side-arm bridges or pseudochiasmata.