Immunotoxicological response of the earthworm Lumbricus terrestris following exposure to cement kiln dusts

Cement kiln dusts are made of a complex mixture of elements. We have evaluated the potential negative impact of those dusts on the immune system of the earthworm Lumbricus terrestris. We specifically studied cell viability and phagocytic activity of coelomocytes extruded during electrical stimulation. We used two modes of exposures: in vitro, and soil incubation using OECD artificial soil media. Extruded coelomocytes were exposed 18 h in vitro to 10, 100, and 500 mg L-1 of cement kiln dust particles. The phagocytosis and the cell viability were determined using a double-laser-flow acquisition cytometry system. Using the double laser allows us to use a dichlorofluorescein diacetate (DCFDA) marker to discriminate the biological cells from the cement kiln dusts. Dead cells are marked using propidium iodide (PI). All three exposure levels showed highly significant impacts on cell viability and phagocytic activity. The in vivo soil incubation was performed using 10, 100, and 1000 mg kg-1 of cement kiln dusts incorporated into the OECD media. Here, to discriminate the biological cells from the mineral dusts we only needed to use PI. The day-to-day variability of the in vivo assay was high and although we can observe an overall reduction in cell viability at the highest concentration tested, no statistically significant effects could be observed on either cell viability or phagocytosis. Copyright 2004 Elsevier Inc. All rights reserved.NRC publication: Ye

Biodegradation of multiple microcystins and cylindrospermopsin in clarifier sludge and a drinking water source: effects of particulate attached bacteria and phycocyanin

The effects of particulate attached bacteria (PAB) and phycocyanin on the simultaneous biodegradation of a mixture of microcystin-LR, YR, LY, LW, LF and cylindrospermopsin (CYN) was assessed in clarifier sludge of a drinking water treatment plant (DWTP) and in a drinking water source. The biomass from lake water and clarifier sludge was able to degrade all microcystins (MCs) at initial concentrations of 10\u3bcgL-1 with pseudo-first order reaction half-lives ranging from 2.3 to 8.8 days. CYN was degraded only in the sludge with a biodegradation rate of 1.0 710-1d-1 and a half-life of 6.0 days. This is the first study reporting multiple MCs and CYN biodegradation in the coagulation-flocculation sludge of a DWTP. The removal of PAB from the lake water and the sludge prolonged the lag time substantially, such that no biodegradation of MCLY, LW and LF was observed within 24 days. Biodegradation rates were shown to increase in the presence of C-phycocyanin as a supplementary carbon source for indigenous bacteria, a cyanobacterial product that accompanies cyanotoxins during cyanobacteria blooms. MCs in mixtures degraded more slowly (or not at all) than if they were degraded individually, an important outcome as MCs in the environment are often present in mixtures. The results from this study showed that the majority of the bacterial biomass responsible for the biodegradation of cyanotoxins is associated with particles or biological flocs and there is a potential for extreme accumulation of cyanotoxins within the DWTP during a transient bloom. \ua9 2015 Elsevier Inc.Peer reviewed: YesNRC publication: Ye

A single N-acetylgalactosamine residue at threonine 106 modifies the dynamics and structure of interferon \u3b12a around the glycosylation site

Enzymatic addition of GalNAc to isotopically labeled IFN\u3b12a produced in Escherichia coli yielded the O-linked glycoprotein GalNAc\u3b1-[ 13C,15N]IFN\u3b12a. The three-dimensional structure of GalNAc\u3b1-IFN\u3b12a has been determined in solution by NMR spectroscopy at high resolution. Proton-nitrogen heteronuclear Overhauser enhancement measurements revealed that the addition of a single monosaccharide unit at Thr-106 significantly slowed motions of the glycosylation loop on the nanosecond time scale. Subsequent addition of a Gal unit produced Gal(\u3b21,3) GalNAc\u3b1[13C,15N]IFN\u3b12a. This extension resulted in a further decrease in the dynamics of this loop. The methodology used here allowed the first such description of the structure and dynamics of an O-glycoprotein and opens the way to the study of this class of proteins. \ua9 2013 by The American Society for Biochemistry and Molecular Biology, Inc.Peer reviewed: YesNRC publication: Ye