Microscopies,spectroscopies and spectrometries applied to marine corrosion of copper

Used in combination, surface analytical techniques can resolve spatial relationships between bacteria and localized corrosion, determine specific corrosion mechanisms and differentiate between abiotic and biotic processes. Confocal laser scanning microscopy and scanning vibrating electrode microscopy were used to demonstrate that marine bacteria and anodic sites are co‐located. Environmental scanning electron microscopy coupled with energy dispersive X‐ray spectros‐copy was used to demonstrate dealloying of nickel from copper: nickel alloys. X‐ray absorption spectroscopy, and transmission electron microscopy equipped with electron energy loss spectrometry were used to determine the speciation of copper associated with corrosion products.     

Isolation and Characterization of Arsenic-Resistant Bacteria from Contaminated Water-Bodies in West Bengal,India

Bengal Basin is known for severe arsenic contamination. In the present study, we have isolated six bacteria from the arsenic contaminated surface water of Bengal Basin. 16S rDNA sequence analysis identified them as Microbacterium oleivorans, Acinetobacter soli, Acinetobacter venetianus, Acinetobacter junii, Acinetobacter baumannii, Acinetobacter calcoaceticus. All the isolates possess arsenic accumulation potential and high molecular weight plasmid (>10 kb). PCR amplification indicated the presence of arsenic-resistance genes (arsB and aoxB) either in the genome or plasmid or in both in the isolated bacteria (except in Acinetobacter venetianus). Exposure to arsenic affected bacterial growth and induced alteration in cytoplasmic membrane integrity.     

Implications of climate change for potamodromous fishes

There is little understanding of how climate change will impact potamodromous freshwater fishes. Since the mid 1970s, a decline in annual rainfall in south‐western Australia (a globally recognized biodiversity hotspot) has resulted in the rivers of the region undergoing severe reductions in surface flows (ca. 50%). There is universal agreement amongst Global Climate Models that rainfall will continue to decline in this region. Limited data are available on the movement patterns of the endemic freshwater fishes of south‐western Australia or on the relationship between their life histories and hydrology. We used this region as a model to determine how dramatic hydrological change may impact potamodromous freshwater fishes. Migration patterns of fishes in the largest river in south‐western Australia were quantified over a 4 year period and were related to a number of key environmental variables including discharge, temperature, pH, conductivity and dissolved oxygen. Most of the endemic freshwater fishes were potamodromous, displaying lateral seasonal spawning migrations from the main channel into tributaries, and there were significant temporal differences in movement patterns between species. Using a model averaging approach, amount of discharge was clearly the best predictor of upstream and downstream movement for most species. Given past and projected reductions in surface flow and groundwater, the findings have major implications for future recruitment rates and population viabilities of potamodromous fishes. Freshwater ecosystems in drying climatic regions can only be managed effectively if such hydro‐ecological relationships are considered. Proactive management and addressing existing anthropogenic stressors on aquatic ecosystems associated with the development of surface and groundwater resources and land use is required to increase the resistance and resilience of potamodromous fishes to ongoing flow reductions.     

Optimization of lipase-catalyzed synthesis of acetylated EGCG by response surface methodology

(−)-Epigallocatechin-3-O-gallate (EGCG) acetylated derivatives, which can be widely used as a natural antioxidant in both lipid containing food and cosmetic applications, were prepared by lipase catalyzed acylation of EGCG with vinyl acetate. Response surface methodology (RSM) and 5-level-4-factor central composite rotatable design (CCRD) were employed to evaluate the effects of synthesis parameters, such as reaction time (6–10 h), temperature (30–50 °C), enzyme amount (1.5–2.5% (w/w) of substrate), and substrate molar ratio of EGCG to vinyl acetate (0.5–1.5) on conversion of EGCG. By using multiple regression analysis, the experimental data were fitted to a second order polynomial model. The most suitable combination of variables was 40 °C, 2.12%, 10 h and 1.13 for the reaction temperature, the enzyme amount, the reaction time, and EGCG/vinyl acetate mole ratio, respectively. At these optimal conditions, the conversion yield reached 87.37%. The presence of mono-, di- and tri-acetylated derivatives in acetylated EGCG was confirmed by LC–MS-MS and identified as 5″-O-acetyl-EGCG, 3″, 5″-2-O-acetyl-EGCG and 5′, 3″, 5″-3-O-acetyl-EGCG by NMR.     

Differentiation-associated changes in membrane proteins of mouse myeloid leukemia cells

The mouse myeloid leukemia cell line (M1) is known to differentiate in vitro into macrophages and granulocytes upon treatment with various inducer including mouse ascitic fluid. Changes of cell surface proteins during differentiation of M1 cells were analyzed by the lactoperoxidase-catalyzed radioiodination method and SDS-polycrylamide slab gel electrphoresis. Treatment of the cells with ascitic fluid changed the electrophoretic pattern of the iodinated proteins, the prominent change being the appearance of a new protein with a molecular weight of 180 000 (P180). Iodinated P180 was also detected in normal macrophages in granulocytes, which are similar to differentiated M1 cells. This protein was metabolically labeled with l-[¹⁴C]fucose, increasing with the period of the treatment. P180 was not expressed on ascitic fluid-treatment of a resistant clone of M1 cells that could not be induced to differentiate. These results indicate that P180 is a glycoprotein that is exposed on the outer surface of differentiated M1 cells, and that its expression is associated with differentiation of the cells.P180 was solubilized from ¹²⁵I-labeled macrophages with detergents bound to concanavalin A-Sepharose. This suggests that P180 is one of the receptors for concanavalin A. Therefore, P180 may contribute partly to the increases in agglutinability by concanavalin A and in the number of concanavalin A binding sites on the surface of M1 cells, which are known to be associated with differentiation of M1 cells.     

COLONIZATION AND SUCCESSION OF ALGAE AND SOIL-ALGAL INTERACTIONS ASSOCIATED WITH DISTURBED AREAS1

The number and abundance of algal species were not significantly different between non-topsoiled areas and top-soiled areas. Successional trends were evident at both sites, since the number of species and their abundance increased over time. Soil-algal interactions were determined by regression analysis. A conceptual model was developed that illustrated the influence of soil chemical properties on algal abundance. Important factors affecting the soil algae were sodium, calcium, potassium, magnesium and certain trace elements. The possible influence of these factors on algal growth is discussed.     

Molecular dynamics simulations of alpha2 --> 8-linked disialoside: conformational analysis and implications for binding to proteins.

Computational methods have played a key role in elucidating the various three-dimensional structures of oligosaccharides. Such structural information, together with other experimental data, leads to a better understanding of the role of oligosaccharide in various biological processes. The disialoside Neu5Ac-alpha2-->8-Neu5Ac appears as the terminal glycan in glycoproteins and glycolipids, and is known to play an important role in various events of cellular communication. Neurotoxins such as botulinum and tetanus require Neu5Ac-alpha2 --> 8-Neu5Ac for infecting the host. Glycoconjugates containing this disialoside and the enzymes catalyzing their biosynthesis are also regulated during cell growth, development, and differentiation. Unlike other biologically relevant disaccharides that have only two linkage bonds, the alpha2-->8-linked disialoside has four: C2-O, O-C8', C8'-C7', and C7'-C6'. The present report describes the results from nine 1 ns MD simulations of alpha2-->8-linked disialoside (Neu5Ac-alpha2-->8-Neu5Ac); simulations were run using GROMOS96 by explicitly considering the solvent molecules. Conformations around the O-C8' bond are restricted to the +sc/+ap regions due to stereochemical reasons. In contrast, conformations around the C2-O and C8'-C7' bonds were found to be largely unrestricted and all the three staggered regions are accessible. The conformations around the C7'-C6' bond were found to be in either the -sc or the anti region. These results are in excellent agreement with the available NMR and potential energy calculation studies. Overall, the disaccharide is flexible and adopts mainly two ensembles of conformations differing in the conformation around the C7'-C6' bond. The flexibility associated with this disaccharide allows for better optimization of intermolecular contacts while binding to proteins and this may partially compensate for the loss of conformational entropy that may be incurred due to disaccharide's flexibility.     

Whole-cell biochips for bio-sensing: integration of live cells and inanimate surfaces

Recent advances in the convergence of the biological, chemical, physical, and engineering sciences have opened new avenues of research into the interfacing of diverse biological moieties with inanimate platforms. A main aspect of this field, the integration of live cells with micro-machined platforms for high throughput and bio-sensing applications, is the subject of the present review. These unique hybrid systems are configured in a manner that ensures positioning of the cells in designated patterns, and enables cellular viability maintenance, and monitoring of cellular functionality. Here we review both animate and inanimate surface properties and how they affect cellular attachment, describe relevant modifications of both types of surfaces, list technologies for platform engineering and for cell deposition in the desired configurations, and discuss the influence of various deposition and immobilization methods on the viability and performance of the immobilized cells.