Revealing copper contamination at the Penang industrial area by using Malaysian mussel watch approach.

Concentrations of Cd, Cu, Ni, Fe, Pb and Zn were determined in the four different parts of soft tissues and shells of Perna viridis collected from 6 geographical sites in the Straits of Malacca in 2005. All the 6 metal concentrations except for Cu were considered low and comparable to those reported in the literature. The Cu concentrations found in the Penang population was found to be extremely elevated and exceeding the ranges for most reported studies as well as safety guidelines, which may be derived from a variety of industrial activities at Penang industrial area. Therefore, the consumption of mussels collected from the intertidal water adjacent to Penang Industrial Area should be given a special caution since human consumption on the mussels could pose toxicological risk of Cu. The present study showed that the Penang coastal water was receiving industrial effluents as a point source of Cu pollution as indicated by the elevated concentration of Cu in the different soft tissues of P. viridis

Enumeration of Oligomerization States of Membrane Proteins in Living Cells by Homo-FRET Spectroscopy and Microscopy: Theory and Application

Protein-protein interactions play a pivotal role in biological signaling networks. It is highly desirable to perform experiments that can directly assess the oligomerization state and degree of oligomerization of biological macromolecules in their native environment. Homo-FRET depends on the inverse sixth power of separation between interacting like fluorophores on the nanometer scale and is therefore sensitive to protein oligomerization. Homo-FRET is normally detected by steady-state or time-resolved fluorescence anisotropy measurements. Here we show by theory and simulation that an examination of the extent of homotransfer as measured by steady-state fluorescence anisotropy as a function of fluorophore labeling (or photodepletion) gives valuable information on the oligomerization state of self-associating proteins. We examine random distributions of monomers, dilute solutions of oligomers, and concentrated solutions of oligomers. The theory is applied to literature data on band 3 protein dimers in membranes, GPI-linked protein trimers in “rafts,” and clustered GFP-tagged epidermal growth factor receptors in cell membranes to illustrate the general utility and applicability of our analytical approach

In vivo covalent cross-linking of photon-converted rare-earth nanostructures for tumour localization and theranostics

The development of precision nanomedicines to direct nanostructure-based reagents into tumour-targeted areas remains a critical challenge in clinics. Chemical reaction-mediated localization in response to tumour environmental perturbations offers promising opportunities for rational design of effective nano-theranostics. Here, we present a unique microenvironment-sensitive strategy for localization of peptide-premodified upconversion nanocrystals (UCNs) within tumour areas. Upon tumour-specific cathepsin protease reactions, the cleavage of peptides induces covalent cross-linking between the exposed cysteine and 2-cyanobenzothiazole on neighbouring particles, thus triggering the accumulation of UCNs into tumour site. Such enzyme-triggered cross-linking of UCNs leads to enhanced upconversion emission upon 808 nm laser irradiation, and in turn amplifies the singlet oxygen generation from the photosensitizers attached on UCNs. Importantly, this design enables remarkable tumour inhibition through either intratumoral UCNs injection or intravenous injection of nanoparticles modified with the targeting ligand. Our strategy may provide a multimodality solution for effective molecular sensing and site-specific tumour treatment.Published versio