Computational insight into complex structures of thorium coordination with N,N’- bis(3-allyl salicylidene)-o-phenylenediamine

Theoretical calculations on the structure of Th(IV) complex containing N, N’- bis(3-allyl salicylidene)-o-phenylenediamine (BASPDA) were performed using density functional theory (DFT) at the B3LYP/6-311G** level. The geometrical structural parameters and infrared spectra results of the Th(BASPDA)₂ from the calculation were compared with the parallel dislocated structure (PDS) obtained in laboratory. The calculated structural parameters were in good agreement with the experimental results. In addition, based on the calculations, a stereoisomer SFS (staggered finger “?+?” structure) of the Th(BASPDA)₂ complex was forecasted by the analysis of a comprehensive method. The charge distribution, structural parameters, bond order indices, spectral properties and thermodynamic properties as well as the molecular orbitals of the two possible crystal structures of Th(BASPDA)₂ were also systematically studied. It was expected that this work could provide insightful information for understanding the properties of Th (BASPDA)₂ complex at the molecular level.     

Rational design of substrate binding pockets in polyphosphate kinase for use in cost-effective ATP-dependent cascade reactions

Applied Microbiology and Biotechnology - Adenosine-5′-triphosphate (ATP) is the energy equivalent of the living system. Polyphosphate (polyP) is the ancient energy storage equivalent of...     

Isolation and characterization of mesophilic cellulose-degrading bacteria from flower stalks-vegetable waste co-composting system

Fifteen mesophilic bacteria with high C(x) cellulase activities were isolated and purified from a mixed-culture enriched from a flower stalks-vegetable waste co-composting system. A CMCase test showed that the enzyme activity of these isolates ranged from 7.9 to 28.0 U ml(-1). Although filter paper degrading capability was low in single culture, significant synergetic cellulose degradation were detected in four groups of mixed cultures, their degradation rates were 23.5%, 26.3%, 19.4% and 24.5%, respectively. Study of morphological and physiological characters of five predominant isolates which possess high CMCase and had positive effect on synergetic cellulose degradation in mixed culture system showed that two of them were closely related to Bacillus pasteurii and Bacillus cereus, whereas the rest belong to the genus Halobacillus, Aeromicrobium and Brevibacterium, respectively.     

A novel function of the human CLS1 in phosphatidylglycerol synthesis and remodeling

Phosphatidylglycerol (PG) is a precursor for the biosynthesis of cardiolipin and a signaling molecule required for various cellular functions. PG is subjected to remodeling subsequent to its de novo biosynthesis in mitochondria to incorporate appropriate acyl content for its biological functions and to prevent the harmful effect of lysophosphatidylglycerol (LPG) accumulation. Yet, a gene encoding a mitochondrial LPG acyltransferase has not been identified. In this report, we identified a novel function of the human cardiolipin synthase (hCLS1) in regulating PG remodeling. In addition to the reported cardiolipin synthase activity, the recombinant hCLS1 protein expressed in COS-7 cells and Sf-9 insect cells exhibited a strong acyl-CoA-dependent LPG acyltransferase activity, which was further confirmed by purified hCLS1 protein overexpressed in Sf-9 cells. The recombinant hCLS1 displayed an acyl selectivity profile in the order of in the order of C18:1 > C18:2 > C18:0 > C16:0, which is similar to that of hCLS1 toward PGs in cardiolipin synthesis, suggesting that the PG remodeling by hCLS1 is an intrinsic property of the enzyme. In contrast, no significant acyltransferase activity was detected from the recombinant hCLS1 enzyme toward lysocardiolipin which shares a similar structure with LPG. In support of a key function of hCLS1 in PG remodeling, overexpression of hCLS1 in COS-7 cells significantly increased PG biosynthesis concurrent with elevated levels of cardiolipin without any significant effects on the biosynthesis of other phospholipids. These results demonstrate for the first time that hCLS1 catalyzes two consecutive steps in cardiolipin biosynthesis by acylating LPG to PG and then converting PG to cardiolipin.     

Peptide-linked molecular beacons for efficient delivery and rapid mRNA detection in living cells

Real-time visualization of specific endogenous mRNA expression in vivo has the potential to revolutionize medical diagnosis, drug discovery, developmental and molecular biology. However, conventional liposome- or dendrimer-based cellular delivery of molecular probes is inefficient, slow, and often detrimental to the probes. Here we demonstrate the rapid and sensitive detection of RNA in living cells using peptide-linked molecular beacons that possess self-delivery, targeting and reporting functions. We conjugated the TAT peptide to molecular beacons using three different linkages and demonstrated that, at relatively low concentrations, these molecular beacon constructs were internalized into living cells within 30 min with nearly 100% efficiency. Further, peptide-based delivery did not interfere with either specific targeting by or hybridization-induced fluorescence of the probes. We could therefore detect human GAPDH and survivin mRNAs in living cells fluorescently, revealing intriguing intracellular localization patterns of mRNA. We clearly demonstrated that cellular delivery of molecular beacons using the peptide-based approach has far better performance compared with conventional transfection methods. The peptide-linked molecular beacons approach promises to open new and exciting opportunities in sensitive gene detection and quantification in vivo.