Relative quantification of the proteomeic changes associated with the mycotoxin zearalenone in the H295R steroidogenesis model

Zearalenone (ZEN) is a mycotoxin with endocrine disrupting effects having vast economic implications in e.g. pig farming. Structurally, ZEN resembles 17b-estradiol, and thus is able to bind to estrogen receptors (ER) in target cells. Because of this, it is also classified as a non-steroidal estrogen, a phytoestrogen, a mycoestrogen, and a growth promoter. Quantitative proteomic analysis was undertaken using stable-isotope labeling by amino acids in cell culture (SILAC) upon exposure of the steroidogenesis cell model H295R with ZEN to elucidate its effect on protein regulation. ZEN significantly regulated 21 proteins, including proteins with known endocrine disrupting effects and several oncogenes. In addition, network analysis using Ingenuity Pathway Analysis showed that ZEN affected the oxidative phosphorylation pathway and the mitochondrial dysfunction pathway, both previously reported to be involved in endocrine dysfunction.

Prospects for ultracold carbon via charge exchange reactions and laser cooled carbides

Strategies to produce an ultracold sample of carbon atoms are explored and assessed with the help of quantum chemistry. After a brief discussion of the experimental difficulties using conventional methods, two strategies are investigated. The first attempts to exploit charge exchange reactions between ultracold metal atoms and sympathetically cooled C+ ions. Ab initio calculations including electron correlation have been conducted on the molecular ions [LiC]+ and [BeC]+ to determine whether alkali or alkaline earth metals are a suitable buffer gas for the formation of C atoms but strong spontaneous radiative charge exchange ensure they are not ideal. The second technique involves the stimulated production of ultracold C atoms from a gas of laser cooled carbides. Calculations on LiC suggest that the alkali carbides are not suitable but the CH radical is a possible laser cooling candidate thanks to very favourable Frank-Condon factors. A scheme based on a four pulse STIRAP excitation pathway to a Feshbach resonance is outlined for the production of atomic fragments with near zero centre of mass velocity.

TIME-RESOLVED ABSORPTION, INFRARED, AND RESONANCE RAMAN-SPECTRA OF THE COMPLEXES [RU(X)(R)(CO)(2)(ALPHA-DIIMINE)] (X=HALIDE R=ALKYL) - INFLUENCE OF X ON THE CHARGE-TRANSFER CHARACTER OF THE LOWEST EXCITED-STATE

Nanosecond time-resolved absorption (TA), resonance Raman (TR(3)), and infrared (TRIR) spectra are reported for several complexes [Ru(X)(R)(CO)(2)(alpha-diimine)] (X = Cl, Br, I; R = Me, Et; alpha-diimine = N,N'-diisopropyl-1,4-diaza-1,3-butadiene (iPr-DAB), pyridine-2-carbaldehyde-N-isopropylimine (iPr-PyCa), 2,2'-bipyridine (bpy)). This is the first instance in which the TA, TR(3), and TRIR techniques have been used to probe excited states in the same series of complexes. The TA spectra of the iodide complexes show a transient absorption between 550 and 700 nm, which does not depend on the solvent but shifts to lower energy in the order iPr-DAB > bpy > iPr-PyCa. This band is assigned to an intraligand transition. For the corresponding chloride and bromide complexes this band occurs at higher energy, most probably because of a change of character of the lowest excited state from XLCT to MLCT. The TRIR spectra show an increase in v(CO) (and k(CO)) on promotion to the excited state; however, the shifts Delta v(CO) show a decrease in the order Cl- > Br- > I-. The TR(3) spectra of the excited complexes [Ru(X)(R)(Co)(2)(iPr-DAB)] show v(s)(CN) of the iPr-DAB ligand 50-80 cm(-1) lower in frequency than for the complexes in their ground state. This frequency shift decreases in the order Cl- > Br- > I-, indicating a decrease of CT character of the lowest excited state in this order. However, going from X = Br to I, the effect on Delta v(CO) is much larger than the decrease of Delta v(s)(CN). This different effect on the CO- and CN-stretching frequencies is assigned to a gradual change in character of the lowest excited state from MLCT to XLCT when Cl- is replaced by Br- and I-. This result confirms a similar conclusion derived from previous resonance Raman and emission experiments on these complexes.

TRANSIENT RESONANCE RAMAN AND RAMAN SPECTROELECTROCHEMICAL STUDIES OF CUI COMPLEXES WITH POLYPYRIDYL LIGANDS

Studies by laser flash photolysis, transient Raman spectroscopy, and Raman and UV-vis spectroelectrochemistry are described in which the techniques have been used in parallel to compare the lowest energy charge-transfer excited states of Cu (1) complexes ([Cu(L)2]+ and [ (PPh3)2Cu(L)]+ [L = 2,2'-biquinoline (BIQ) or 6,7-dihydro-5,8-dimethyldibenzo[b,j] [1,10]-phenanthroline (DMCH)) with the species produced by electrochemical reduction in the same group of complexes. Transient resonance Raman spectra for the metal-to-ligand charge-transfer (MLCT) states of [Cu(DMCH)2]+ (1), [Cu(BIQ)2]+ (2), [Cu(DMCH)(PPh3)2]+ (3), and [Cu(BIQ)(PPh3)2]+ (4) are compared with the resonance Raman spectra of the same group of complexes following one-electron electrochemical reduction of the DMCH and BIQ ligands. The UV-vis and resonance Raman evidence suggests that the electrochemical reduction of the [Cu(I)L2]+ species proceeds according to the sequence [LCu(I)L]+ -->e- [LCu0L] -->e- [L.-Cu(I)L.-]-. Several features assignable to modes of the electrochemically generated DMCH.-and BIQ'- radical anions exhibit a close correspondence in both frequency and relative intensity with counterparts in the spectra of the MLCT states of 1 and 2. A notable exception is a band near 1590 cm-1 in the spectra of the electrochemically reduced species which occurs some 15 cm-1 lower in the corresponding spectra of the excited-state species. It is suggested that the shift may reflect the change in oxidation state of the metal center from Cu(I) to Cu(II) which occurs as a result of charge-transfer excitation.

Relative metabolomic flux: Predicting changes in the environmental metabolome from the metagenome

Background: The world's oceans are home to a diverse array of microbial life whose metabolic activity helps to drive the earth's biogeochemical cycles. Metagenomic analysis has revolutionized our access to these communities, providing a system-scale perspective of microbial community interactions. However, while metagenome sequencing can provide useful estimates of the relative change in abundance of specific genes and taxa between environments or over time, this does not investigate the relative changes in the production or consumption of different metabolites.
Results: We propose a methodology, Predicted Relative Metabolic Turnover (PRMT) that defines and enables exploration of metabolite-space inferred from the metagenome. Our analysis of metagenomic data from a time-series study in the Western English Channel demonstrated considerable correlations between predicted relative metabolic turnover and seasonal changes in abundance of measured environmental parameters as well as with observed seasonal changes in bacterial population structure.
Conclusions: The PRMT method was successfully applied to metagenomic data to explore the Western English Channel microbial metabalome to generate specific, biologically testable hypotheses. Generated hypotheses linked organic phosphate utilization to Gammaproteobactaria, Plantcomycetes, and Betaproteobacteria, chitin degradation to Actinomycetes, and potential small molecule biosynthesis pathways for Lentisphaerae, Chlamydiae, and Crenarchaeota. The PRMT method can be applied as a general tool for the analysis of additional metagenomic or transcriptomic datasets.

Interaction strength, food web topology and the relative importance of species in food webs

P>1. We established complex marine communities, consisting of over 100 species, in large subtidal experimental mesocosms. We measured the strength of direct interactions and the net strength of direct and indirect interactions between the species in those communities, using a combination of theoretical and empirical approaches.