Effective elimination of biofilm formed with waterborne pathogens using copper nanoparticles.

In this paper, the self assembling properties of taurolipids were used to prepare stable copper nanoparticles (CuNPs), and demonstrated the ability of CuNPs to eradicate the biofilms formed by waterborne pathogens. The synthesized CuNPs display wine red color and exhibited surface plasmon resonance with a maximum at 590 nm. Transmission electron microscopy showed that the CuNPs are well-dispersed with spherical morphology and the size range between 5 and 12 nm. The powder X-ray diffraction study revealed that the CuNPs was free from copper oxide impurities and crystalline with the face centered cubic structure. The CuNPs exhibited excellent anti-biofilm activity against water borne pathogens such as Escherichia coli, Pseudomonas aeruginosa, Salmonella typhi, and Shigella flexneri. Light microscopy and scanning electron microscopy (SEM) study revealed that CuNPs eliminates the mature biofilm at the minimum biofilm eradication concentration of 12.5 µM. The antimicrobial activity of the CuNPs was observed at the minimum inhibitory concentration of 25 µM, indicating the reported CuNPs exhibit true anti-biofilm effect. Fluorescence microscopy and SEM study proved that CuNPs kills the bacteria through membrane damage. The possibility to use CuNPs in cleaning biofilm formed on storage containers was demonstrated through removing the mature biofilm formed on a glass pipe.

Sphingolipid transfer proteins defined by the GLTP-fold.

Glycolipid transfer proteins (GLTPs) originally were identified as small (~24 kDa), soluble, amphitropic proteins that specifically accelerate the intermembrane transfer of glycolipids. GLTPs and related homologs now are known to adopt a unique, helically dominated, two-layer 'sandwich' architecture defined as the GLTP-fold that provides the structural underpinning for the eukaryotic GLTP superfamily. Recent advances now provide exquisite insights into structural features responsible for lipid headgroup selectivity as well as the adaptability of the hydrophobic compartment for accommodating hydrocarbon chains of differing length and unsaturation. A new understanding of the structural versatility and evolutionary premium placed on the GLTP motif has emerged. Human GLTP-motifs have evolved to function not only as glucosylceramide binding/transferring domains for phosphoinositol 4-phosphate adaptor protein-2 during glycosphingolipid biosynthesis but also as selective binding/transfer proteins for ceramide-1-phosphate. The latter, known as ceramide-1-phosphate transfer protein, recently has been shown to form GLTP-fold while critically regulating Group-IV cytoplasmic phospholipase A2 activity and pro-inflammatory eicosanoid production.

Synthesis and characterization of zinc sulfide quantum dots and their interaction with snake gourd (Trichosanthes anguina) seed lectin.

Owing to the use of quantum dots in biological labeling, and the specific interaction of lectins with tumor cells, studies on lectin-QDs interaction are of potential interest. Herein, we report a facile method to prepare zinc sulfide quantum dots (ZnS QDs) using pectin as a capping agent and studied their interaction with snake gourd seed lectin (SGSL) by fluorescence spectroscopy. The QDs were characterized by X-ray diffraction, high-resolution transmission electron microscopy, UV-Vis absorption and fluorescence spectroscopy. The thermodynamic forces governing the interaction between ZnS-QDs and SGSL have been delineated from the temperature dependent association constant. These results suggest that the binding between ZnS QDs and SGSL is governed by enthalpic forces with negative entropic contribution. The red shift of synchronous fluorescence spectra showed that the microenvironment around the tryptophan residues of SGSL was perturbed by ZnS-QDs. The obtained results suggest that the development of optical bioimaging agents by using the conjugated lectin-QDs would be possible to diagnose cancerous tissues.