A tip-high, Ca2+-interdependent, reactive oxygen species gradient is associated with polarized growth in Fucus serratus zygotes

We report the existence of a tip-high reactive oxygen species (ROS) gradient in growing Fucus serratus zygotes, using both 5-(and 6-) chloromethyl-2',7'-dichlorodihydrofluorescein and nitroblue tetrazolium staining to report ROS generation. Suppression of the ROS gradient inhibits polarized zygotic growth; conversely, exogenous ROS generation can redirect zygotic polarization following inhibition of endogenous ROS. Confocal imaging of fluo-4 dextran distributions suggests that the ROS gradient is interdependent on the tip-high [Ca2+](cyt) gradient which is known to be associated with polarized growth. Our data support a model in which localized production of ROS at the rhizoid tip stimulates formation of a localized tip-high [Ca2+](cyt) gradient. Such modulation of intracellular [Ca2+](cyt) signals by ROS is a common motif in many plant and algal systems and this study extends this mechanism to embryogenesis.

Protein surface recognition using geometrically pure Ru(II) tris(bipyridine) derivatives

This manuscript illustrates that the geometric arrangement of protein-binding groups around a ruthenium(II) core leads to dramatic differences in cytochrome c (cyt c) binding highlighting that it is possible to define synthetic receptors with shape complementarity to protein surfaces.

Phase I and II biotransformation enzymes and polycyclic aromatic hydrocarbons in the Mediterranean mussel (Mytilus galloprovincialis, Lamarck, 1819) collected in front of an oil refinery

The aim of the present study was to investigate the responses of phase I and II biotransformation enzymes and levels of PAHs in the Mediterranean mussel (Mytilus galloprovincialis, Lamarck, 1819) collected from three sites at different distance from an oil refinery. Phase I enzyme activities as NAD(P)H-cyt c red, NADH ferry red, B(a)PMO and phase II as UDPGT. GST were measured in digestive gland while 16 PAHs (US-EPA) in whole soft tissue. An added value to the data obtained in the present study rely on the RDA analysis which showed close correlations between PAHs levels and phase I enzyme activities in mussels collected in front of the refinery. And again a significant spatial correlation between B(a)P levels and NADPH-cyt c red activities was observed using linear models. No differences among sites for B(a) PMO and phase II GST activities were observed, while the application of UDPGT as biomarkers requires further investigation. (C) 2012 Elsevier Ltd. All rights reserved.

Protein destabilisation by ruthenium(II) tris-bipyridine based protein-surface mimetics

Highly functionalised ruthenium(II) tris-bipyridine receptor 1 which acts as a selective sensor for equine cytochrome c (cyt c) is shown to destabilise the native protein conformation by around 25 degrees C. Receptors 2 and 3 do not exert this effect confirming the behaviour is a specific effect of molecular recognition between 1 and cyt c, whilst the absence of a destabilising effect on 60% acetylated cyt c demonstrates the behaviour of 1 to be protein specific. Molecular recognition also modifies the conformational properties of the target protein at room temperature as evidenced by ion-mobility spectrometry (IMS) and accelerated trypsin proteolysis.