First assessment of butyltins (BuTs) contamination of the Montenegrin coast (Southeast Adriatic): Tributyltin (TBT) poses a threat to the marine ecosystem.

This study presents the first assessment of butyltins (BuTs) pollution of the Montenegrin coast. The distribution of tributyltin (TBT), dibutyltin (DBT) and monobutyltin (MBT) was investigated in mussels, sediments and water overlying sediment after the sediment resuspension. The results showed that the investigated sites (marinas, ports, shipyards) are contaminated with BuTs (19-402 ng (Sn)/g in mussels; 43-20,641 ng (Sn)/g in sediments; 9-566 ng (Sn)/L in overlying waters). The measured TBT concentrations indicate that toxic effects on marine organisms are expected at most locations. The simultaneous analysis of BuTs and total Sn in sediment cores allowed the assessment of TBT historical input, while it was demonstrated that resuspension of contaminated sediments leads to the release of all BuTs into the water column. This study shows that, despite the ban of TBT-based antifouling paints more than a decade ago, pollution of the marine environment with TBT is still a problem and regular monitoring remains essential.

Levels and distribution of cobalt and nickel in the aquatic macrophytes found in Skadar Lake, Montenegro.

Macrophytes react to changes in the quality of the environment in which they live (water/sediment), and they are good bioindicators of surface water conditions. In the present study, the content of the metals cobalt (Co) and nickel (Ni) was determined in the sediment, the water, and different organs of macrophytes from six localities around Lake Skadar, across four different seasons of year. The aquatic macrophytes that have been used as bioindicator species in this study are Phragmites australis (an emerged species), Ceratophyllum demersum (a submerged species), and Lemna minor (a floating species). The aim of this study was to determine the distribution of metals in macrophyte tissues and also to discover the degree of bioaccumulation of the investigated metals, depending both on the location and on the season. The content of Co and Ni in the examined parts of the macrophytes was in the range of 0.04-8.78 and 0.30-28.5 ppm, respectively. The greatest content of the investigated metal in the organs of P. australis and C. demersum was recorded at the beginning of and during the growing season. Greater concentrations of metals in the tissue of L. minor were observed at the end of the growing season.

Environmental Status and geochemical assessment Sediments of Lake Skadar, Montenegro.

The environmental mobility and geochemical partitioning of ten metals were examined in sediments collected from the six locations around Lake Skadar in Montenegro. A three-step sequential extraction procedure was used to determine the distribution of the metals in various substrates of lacustrine sediments, and the concentrations were measured in the liquid extract by ICP-OES. The largest portion of the total amount of cadmium, strontium and manganese can be found in sediment bound to the hydrated iron and manganese oxides; cobalt, lead, copper and nickel in the oxidizable fraction and the highest portion of chromium, vanadium and zinc are in the residual fraction. The most mobilized and potentially mobile metals are strontium, cadmium and cobalt while the most immobilized metals are chromium, vanadium and zinc. Based on geochemical parameters, an assessment of sediment contamination by the investigated metals was performed and the results showed potential risks ranging from "no risk" to "low risk" to the environment.

Highly efficient Michael-type addition of acetaldehyde to ß-nitrostyrenes by whole resting cells of Escherichia coli expressing 4-oxalocrotonate tautomerase.

A novel whole cell system based on recombinantly expressed 4-oxalocrotonate tautomerase (4-OT) was developed and shown to be an effective biocatalyst for the asymmetric Michael addition of acetaldehyde to ß-nitrostyrenes. Optimal ratio of substrates (2mM ß-nitrostyrenes and 20mM acetaldehyde) and biocatalyst of 5 g of cell dry weight of biocatalyst per liter was determined. Through further bioprocess improvement by sequential addition of substrate 10mM nitrostyrene biotransformation was achieved within 150 min. Excellent enantioselectivity (>99% ee) and product yields of up to 60% were obtained with ß-nitrostyrene substrate. The biotransformation product, 4-nitro-3-phenyl-butanal, was isolated from aqueous media and further transformed into the corresponding amino alcohol. The biocatalyst exhibited lower reaction rates with p-Cl-, o-Cl- and p-F-ß-nitrostyrenes with product yields of 38%, 51%, 31% and ee values of 84%, 88% and 94% respectively. The importance of the terminal proline of 4-OT was confirmed by two proline enriched variants and homology modeling.

A useful synthetic equivalent of a hydroxyacetone enolate.

Indium promoted allylation of carbonyl compounds with 4-(bromomethyl)-1,3-dioxol-2-one diastereoselectively affords anti-α,ß-dihydroxyketones, protected as enol carbonates. These initial products can be deprotected to free dihydroxyketones or transformed under mild conditions into the corresponding cyclic carbonates, which constitutes a useful approach to hydroxyacetone aldols.