Multifunctional role for fetuin (fetal protein) in lipid transport.

Recent studies from this laboratory have shown that fetuin 1) is nearly 50-fold more efficient than albumin in incorporating exogenous fatty acids into cultured cells, (JBC, 265: 5883, 1990), and 2) is associated with a lipoprotein-like particle (FASEB J. 3: 2075-2080, 1989). In the present study, this lipid-containing fraction (FLP) was isolated by ultracentrifugation, and its effect on cholesterol efflux from cultured human skin fibroblasts and Hep-G2 cells prelabeled with [14C]cholesterol was investigated. FLP fraction caused a significant efflux of [14C]cholesterol from cells, the same in magnitude as HDL. This effect of fetuin supranatant fraction increased proportionately with concentration and time. Similar results were observed with Hep-G2 cells. This ability to induce efflux of cholesterol was confirmed by a decrease in cholesterol mass of cells after 24 h incubation with FLP. The ultracentrifugal bottom (infranatant) fraction of fetuin (FI) was ineffective in this regard. However, FI was more effective in the incorporation of exogenous fatty acids into cellular triglycerides. These studies suggest that the fetuin molecule is a multifunctional protein (delivery of fatty acids to cells and cholesterol efflux from cells) which may play a role in lipid transport during fetal life.     

9-beta-D-Arabinofuranosyl-8-n-butylaminoadenine, a C-8 substituted nucleoside in the anti conformation. Crystallographic and NMR studies

The protein NMR spectrum of 9-beta-D-arabinofuranosyl-8-n-butylaminoadenine shows an unusually low-field 5'-hydroxyl proton resonance, which has been interpreted in terms of an anti glycosidic conformation together with an 05' ... N8 intramolecular hydrogen bond. Confirmatory evidence for this was obtained by an X-ray crystallographic study; in the crystal, the glycosidic angle chi is 52.7 degrees and the sugar pucker is C3' endo-C4' exo.     

Human Ubiquitin C Promoter Based Expression of Erythropoietin in CHO K1 Cell Lines: A Simple Transfectants Screening Approach

Erythropoietin (EPO), a glycoprotein hormone that regulates the production of erythrocytes in the human body, is of clinical importance in the treatment of anemia. Low expression levels of this recombinant hormone and time-consuming screening methods have made its commercial production expensive. Cloning of human EPO gene in a shuttle vector pUB6/V5-HisB driven by human ubiquitin C promoter and its transfection in CHO K1 cell lines by electroporation resulted in a moderate level of EPO expression. The limiting-dilution screening method required several months to obtain high expression stable transfectants but needed only short duration for selection in contrast to the present screening strategy. The supernatants of stably transfected cells were found to be biologically active by in vitro erythroid cluster forming activity.     

Loss Mechanisms in Thick‐Film Low‐Bandgap Polymer Solar Cells

Polymer bulk heterojunction solar cells based on low bandgap polymer:fullerene blends are promising for next generation low‐cost photovoltaics. While these solution‐processed solar cells are compatible with large‐scale roll‐to‐roll processing, active layers used for typical laboratory‐scale devices are too thin to ensure high manufacturing yields. Furthermore, due to the limited light absorption and optical interference within the thin active layer, the external quantum efficiencies (EQEs) of bulk heterojunction polymer solar cells are severely limited. In order to produce polymer solar cells with high yields, efficient solar cells with a thick active layer must be demonstrated. In this work, the performance of thick‐film solar cells employing the low‐bandgap polymer poly(dithienogermole‐thienopyrrolodione) (PDTG‐TPD) was demonstrated. Power conversion efficiencies over 8.0% were obtained for devices with an active layer thickness of 200 nm, illustrating the potential of this polymer for large‐scale manufacturing. Although an average EQE > 65% was obtained for devices with active layer thicknesses > 200 nm, the cell performance could not be maintained due to a reduction in fill factor. By comparing our results for PDTG‐TPD solar cells with similar P3HT‐based devices, we investigated the loss mechanisms associated with the limited device performance observed for thick‐film low‐bandgap polymer solar cells.     

Dimerization of a flocculent protein from Moringa oleifera: experimental evidence and in silico interpretation

Many proteins exist in dimeric and other oligomeric forms to gain stability and functional advantages. In this study, the dimerization property of a coagulant protein (MO_2.1) from Moringa oleifera seeds was addressed through laboratory experiments, protein–protein docking studies and binding free energy calculations. The structure of MO_2.1 was predicted by homology modelling, while binding free energy and residues-distance profile analyses provided insight into the energetics and structural factors for dimer formation. Since the coagulation activities of the monomeric and dimeric forms of MO_2.1 were comparable, it was concluded that oligomerization does not affect the biological activity of the protein.     

Non hemolytic short peptidomimetics as a new class of potent and broad-spectrum antimicrobial agents

Since the bacterial resistance to antibiotics is increasing rapidly, numerous studies have contributed to the design and synthesis of potent synthetic mimics of antimicrobial peptides (AMPs). In an attempt to find the pharmacophore of short antimicrobial peptidomimetics through systematic tuning of hydrophobic and hydrophilic patterns, we have identified a set of short histidine-derived antimicrobial peptides (SAMPs) with potent and broad-spectrum activity. A combination of high antimicrobial activity against methicillin-resistant Staphylococcus aureus (MRSA), without hemolytic activity and proteolytic stability makes these molecules promising candidates for novel antimicrobial therapeutics.     

Reduced Recombination in High Efficiency Molecular Nematic Liquid Crystalline: Fullerene Solar Cells

Bimolecular recombination in bulk heterojunction organic solar cells is the process by which nongeminate photogenerated free carriers encounter each other, and combine to form a charge transfer (CT) state which subsequently relaxes to the ground state. It is governed by the diffusion of the slower and faster carriers toward the electron donor–acceptor interface. In an increasing number of systems, the recombination rate constant is measured to be lower than that predicted by Langevin's model for relative Brownian motion and the capture of opposite charges. This study investigates the dynamics of charge generation, transport, and recombination in a nematic liquid crystalline donor:fullerene acceptor system that gives solar cells with initial power conversion efficiencies of >9.5%. Unusually, and advantageously from a manufacturing perspective, these efficiencies are maintained in junctions thicker than 300 nm. Despite finding imbalanced and moderate carrier mobilities in this blend, strongly suppressed bimolecular recombination is observed, which is ≈150 times less than predicted by Langevin theory, or indeed, more recent and advanced models that take into account the domain size and the spatial separation of electrons and holes. The suppressed bimolecular recombination arises from the fact that ground‐state decay of the CT state is significantly slower than dissociation.     

Isolation and characterization of biosurfactant producing <Emphasis Type="Italic">Bacillus</Emphasis> sp. from diesel fuel-contaminated site

Among hydrocarbon pollutants, diesel oil is a complex mixture of alkanes and aromatic compounds which are often encountered as soil contaminants leaking from storage tanks and pipelines or as result of accidental spillage. One of the best ecofriendly approaches is to restore contaminated soil by using microorganisms able to degrade those toxic compounds in a bioremediation process. In the present study, nineteen bacteria were isolated by enrichment culture technique from diesel spilled soil collected from electric generator shed of NBAIM, Mau. All the isolates were subjected to screening for lipase production and twelve isolates were found to be positive for lipase. When the isolates were screened for biosurfactant production using CTAB-methylene blue agar plates, only one isolate viz. 2NBDSH3 was found positive which was found to be phylogenetically closely related with Bacillus flexus. Despite having low emulsification index, the bacterium could degrade 88.6% of diesel oil in soil. Biosurfactant from the isolate was extracted and characterized through infra-red spectroscopy which indicated its possible lipopeptide nature which was further supported by strong absorption in UV range in the UV-Vis spectrum. The results of the present study indicated that the isolate either does not produce any bioemulsifier or produces very low amount of emulsifier rather it produces a lipopeptide biosurfactant which helps in degradation of diesel oil by lowering the surface tension. The bacterium thus isolated and characterized can serve as a promising solution for ecofriendly remediation of bacterium diesel contaminated soils.     

Targetted localisation and imaging of a murine lymphoma using 131I-labelled monoclonal antibody

In vivo tumor targetting with radiolabelled monoclonal antibodies is a promising approach for the diagnosis and therapy of tumors. A specific monoclonal antibody (mAb), DLAB was generated to the Dalton's lymphoma associated antigen (DLAA) from Haemophilus paragallinarum-induced spontaneous fusion. In order to study the tumor localisation and biodistribution properties of the monoclonal antibody, scintigraphic studies were performed using the radiolabelled DLAB. 131-labelled DLAB was administered intravenously into Swiss mice bearing Dalton's lymphoma and external scintiscanning was performed at different time intervals. Clear tumor images were obtained which revealed selective and specific uptake of radiolabel and the results were compared with biodistribution data. The radioiodinated monoclonal antibody showed fast tumor uptake which increased significantly to 14.6% injected dose (ID)/g at 12 hr post-injection. Enhanced blood clearance of radioactivity resulted in higher tumor/blood ratio of 5.96 at 48 hr. 131I-labelled DLAB resulted in selective and enhanced uptake of the radioactivity by the tumor compared to the non-specific antibody and the results suggest the potential use of spontaneous fusion for producing specific monoclonal antibodies for tumor detection and therapy.