Reactions of the haloalcohols HO(CH2)nCl (n = 2, 3) with platinum(II) - alkynyl and -alkyne complexes. X-ray crystal structure of trans-[Pt(Me) {C(OCH2CH2Cl) (CH2Ph)} (PPh3)2] [BF4]

The chloro complexes trans-[Pt(Me)(Cl)(PPh₃)₂], after treatment with AgBF₄, react with 1-alkynes HC---C---R in the presence of NEt₃ to afford the corresponding acetylide derivatives trans-[Pt(Me) (C---C---R) (PPh₃)₂] (R = p-tolyl (1), Ph (2), C(CH₃)₃ (3)). These complexes, with the exception of the t-butylacetylide complex, react with the chloroalcohols HO(CH₂)_nCl (n = 2, 3) in the presence of 1 equiv. of HBF₄ to afford the alkyl(chloroalkoxy)carbene complexes trans-[Pt(Me) {C[O(CH₂)_nCl](CH₂R) } (PPh₃)₂][BF₄] (R = p-tolyl, N = 2 (4), N = 3 (5); R=Ph, N = 2 (6)). A similar reaction of the bis(acetylide) complex trans-[Pt(C---C---Ph)₂(PMe₂Ph)₂] with 2 equiv. HBF₄ and 3-chloro-1-propanol affords trans-[Pt(C---CPh) {C(OCH₂CH₂CH₂Cl)(CH₂Ph) } (PMe₂Ph)₂][BF₄] (7). T alkyl(chloroalkoxy)-carbene complex trans-[Pt(Me) {C(OCH₂CH₂Cl)(CH₂Ph) } (PPh₃)₂][BF₄] (8) is formed by reaction of trans-[Pt(Me)(Cl)(PPh₃)₂], after treatment with AgBF₄ in HOCH₂CH₂Cl, with phenylacetylene in the presence of 1 equiv. of n-BuLi. The reaction of the dimer [Pt(Cl)(μ-Cl)(PMe₂Ph)]₂ with p-tolylacetylene and 3-chloro-1-propanol yields cis-[PtCl₂{C(OCH₂CH₂CH₂Cl)(CH₂C₆H₄-p-Me}(PMe₂Ph)] (9). The X-ray molecular structure of (8) has been determined. It crystallizes in the orthorhombic system, space group Pna2₁, with a = 11.785(2), B = 29.418(4), C = 15.409(3) Å, V = 4889(1) ų and Z = 4. The carbene ligand is perpendicular to the Pt(II) coordination plane; the PtC(carbene) bond distance is 2.01(1) Å and the short C(carbene)-O bond distance of 1.30(1) Å suggests extensive electronic delocalization within the Pt---C(carbene)---O moietry.     

Response of Benthic Protozoa and Thraustochytrid Protists to Fish Farm Impact in Seagrass (Posidonia oceanica) and Soft-Bottom Sediments

We investigated the impact of fish farm biodeposition on benthic bacteria, thraustochytrid protists, and heterotrophic protozoa (nanoflagellates and ciliates) in an oligotrophic area of the Mediterranean Sea. The fish farm impact was investigated both on a seagrass (Posidonia oceanica) bed and on soft bottom sediments. In both systems, sediment samples were collected with a multicontrol sampling strategy (i.e., beneath the fish farm and at three control sites per system). The uneaten food pellets supplied to the fish determined the accumulation of sediment organic matter and the enhancement of protein content in impacted sediments (both seagrass bed and soft sediments). In both systems, the abundance and biomass of heterotrophic protists increased significantly beneath the fish farm, but the structure of the protist assemblages responded differently in vegetated and unvegetated sediments. Thraustochytrid abundance increased significantly in impacted seagrass. These results provide evidence that the structure of protist assemblages respond significantly to fish farm biodeposition and indicate that the monitoring of these benthic components provides complementary information for the assessment of the fish farm impact on the benthic systems.     

Synthesis and cyclization reactions of platinum(II)-coordinated arsonium-substituted phenyl isocyanides, o-(IR3As-CH2)C6H4NC

The arsonium-substituted isocyanides, o-(I⁻⁺R₃AsCH₂)C₆H₄NC (AsR₃=AsPh₃, L₁; AsMePh₂, L₂; AsMe₂Ph, L₃), were prepared by reaction of o-(chloromethyl)phenyl isocyanide, o-(CH₂Cl)C₆H₄NC, with a slight molar stoichiometric amount of the arsine in the presence of a 3-fold excess of NaI in acetone at room temperature. The isocyanides L₁-L₃ coordinate to some Pt(II) complexes such as trans-[PtX{o-(I⁻⁺R₃AsCH₂)C₆H₄NC}(PPh₃)₂] [BF₄] (AsR₃=AsPh₃, 1; AsMePh₂, 2; AsMe₂Ph, 3; X=Cl, I) and [PtX{o-(I⁻⁺R₃AsCH₂)C₆H₄NC}(Ph₂PCHCHPPh₂)] [BF₄] (AsR₃=AsMePh₂, 4; X=Cl, I). Complexes 2-4 are converted in CH₂Cl₂ at room temperature in the presence of NEt₃ to the corresponding indolidin-2-ylidene derivatives trans-[PtX{(AsR₃)}(PPh₃)₂]BF₄] (AsR₃=AsPh₃, 5; AsMePh₂, 6; AsMe₂Ph, 7) and [PtX{(AsMePh₂)}(Ph₂PCHCHPPh₂)][BF₄] (8).     

Biochemical genetic differentiation between Pomatoschistus marmoratus and P. tortonesei

Several diagnostic genetic markers were identified in Pomatoschistus marmoratus and P. tortonesei using polyacrylamide gel electrophoresis (PAGE) of allozymes. Twenty-one loci were resolved, including the electrophoretic pattern of muscle proteins. The MDH*, PGM-,2*, EST-1,2*, FUM* and PGI-2* loci exhibited different alleles which were fixed for the two species being analysed. Genetic distance, as calculated by Nei's index, showed a value of 0·413. Environmental hypersalinity, could have influenced the geographical distribution of P. tortonesei .     

Effects of cadmium and uranium on some in vitro renal targets

Metals are major pollutants not only in occupational settings but also in the general environment. Chronic exposure of workers has been related to severe damage, especially at the renal level. While toxic compounds such as metals are well known to severely impair tubular functions, it is clear that nephrotoxicants can act on various other renal targets, i.e., vascular and glomerular ones.In vitro models are available to assess these toxicities and can be used to better understand the different cell targets. This paper summarizes data obtained in our laboratory after exposure of isolated renal structures such as glomeruli, and cell cultures such as glomerular mesangial and tubular epithelial cells, to cadmium and uranium. Morphometric studies by image analysis of isolated glomeruli and mesangial cultured cells showed that cadmium and uranium induced a dose- and time-dependent glomerular contraction accompanied by disorganization of the cytoskeleton. Classical viability tests demonstrated various factors influencing the metal toxicity. The important roles of pH, extracellular protein concentrations and the nature of the anion accompanying the metal were demonstrated. These data obtained inin vitro models provide better understanding of the cytotoxicity after metal uptake and accumulation in glomerular and tubular cells. Moreover, the glomerular and tubular cytotoxicity they induce may be correlated with severe renal hemodynamic changes in vivo. Finally, we briefly present eventual improvements forin vitro renal models by the use of new cell models such as immortalized human cell lines or by the introduction of porous supports and perifusion devices. This revised version was published online in August 2006 with corrections to the Cover Date.     

Meiofauna associated with vermetid reefs: the role of macroalgae in increasing habitat size and complexity

Coral Reefs - We present the first dataset of meiofauna associated with vermetid reefs (biogenic constructions of Mediterranean intertidal habitat) in two areas along the northern coast of Sicily,...     

The trophic niche of sculpins Cottus spp. in forage fish assemblages of boreal lakes

We compared the trophic niches of freshwater sculpins Cottus spp. with those of other co-habiting forage fishes in two groups of boreal lakes with distinct habitats and fish communities. Near North Lakes (45° 00′ to 47° 30′ N) were deeper, stratified and contained lake trout Salvelinus namaycush as the apex piscivore, whereas Far North Lakes (51° 10′ to 52° 20′ N) were shallower, did not stratify and contained pike Esox lucius and walleye Sander vitreus as the apex piscivores. Trophic niches of sculpins and other forage fishes were compared based on niche metrics calculated from muscle stable carbon (δ¹³C) and nitrogen (δ¹⁵N) isotope ratios. In Near North Lakes, sculpins were found almost exclusively in deep, offshore waters and their niche positions reflected a greater reliance on pelagic production (lower δ¹³C) and a higher trophic elevation (higher δ¹⁵N) compared with most other forage fishes. Furthermore, sculpins in Near North Lakes tended to have larger trophic niches (occupied greater area in δ¹³C– δ¹⁵N space), particularly in the food chain (δ¹⁵N) dimension, than other cohabiting forage fishes. In contrast, sculpins in Far North Lakes were commonly found in the nearshore and had trophic niche positions and sizes that were similar to those of the other cohabiting forage fishes. This study illustrates the flexibility in the realised trophic niches of sculpins in relation to habitat availability and fish community composition in boreal lakes.     

Reactivity of trans-[PtCl2(NCMe)2] with cycloaliphatic amines: An ESI and NMR study. X-ray structure of

The reactivity of the cyclic primary aliphatic amines cyclopropyl-, cyclopentyl- and cyclohexylamine with cis- and trans-[PtCl₂(NCMe)₂], under the same experimental conditions, is compared. Whereas cis-[PtCl₂(NCMe)₂] yields the neutral diamidine compounds, the reactions with trans-[PtCl₂(NCMe)₂] take place either with addition or substitution processes yielding the neutral diamidine complexes trans-[PtCl₂(Amidine)₂], the monocationic trans-[PtCl(Amine)(Amidine)₂]Cl and the dicationic trans-[Pt(Amine)₂(Amidine)₂]Cl₂ salts. An NMR and ESI study indicate that the main species formed is the monocationic trans-[PtCl(Amine)(Amidine)₂]Cl complex.The X-ray structure of is reported and its supramolecular arrangement is described.     

Liver Volume and Visceral Obesity in Women with Hepatic Steatosis Undergoing Gastric Banding

Objective: To investigate the relationships between visceral obesity and hepatic steatosis in obese patients undergoing adjustable silicone gastric banding with the LAP‐BAND. Research Methods and Procedures: Six premenopausal, morbidly obese women with an ultrasonographic diagnosis of liver steatosis were evaluated before surgery and 8 and 24 weeks after surgery. Liver volume and body fat distribution were simultaneously analyzed by total‐body multislices magnetic resonance imaging. Results: Before surgery, the only variable found to be correlated with liver volume was visceral adipose tissue volume (r = 0.91; p < 0.01). Weight loss was 9.9 ± 3.8 kg in the period from 0 to 8 weeks (p < 0.01) and 7.1 ± 4.9 kg in the the period from 8 to 24 weeks (p < 0.05). Total fat showed a statistically significant reduction of 6.2 ± 4.0 liters in the 0‐ to 8‐week period and a further significant reduction of 7.7 ± 3.9 liters in the 8‐ to 24‐week period. Visceral adipose tissue showed a statistically significant reduction of 1.0 ± 0.9 liters in the 0‐ to 8‐week period (p < 0.05) but only a further, not significant reduction of 0.6 ± 0.7 liters in the 8‐ to 24‐week period. The relative reduction of visceral fat in the 0‐to 8‐week period was higher than the relative reduction of total fat. Liver volume also showed a statistically significant reduction of 0.24 ± 0.26 liters in the first phase of weight loss (p < 0.05), corresponding to a relative reduction of 12.3 ± 10.6%. During the 8‐ to 24‐week period, liver volume was substantially stable. Discussion: Hepatomegaly was associated with visceral obesity in morbidly obese women with liver steatosis. In the phase of rapid weight loss after gastric surgery, a preferential mobilization of visceral fat, compared with total adipose tissue, occurred. This preferential visceral fat loss was associated with a significant reduction in liver volume.     

Predicting shifting sustainability trade‐offs in marine finfish aquaculture under climate change

Defining sustainability goals is a crucial but difficult task because it often involves the quantification of multiple interrelated and sometimes conflicting components. This complexity may be exacerbated by climate change, which will increase environmental vulnerability in aquaculture and potentially compromise the ability to meet the needs of a growing human population. Here, we developed an approach to inform sustainable aquaculture by quantifying spatio‐temporal shifts in critical trade‐offs between environmental costs and benefits using the time to reach the commercial size as a possible proxy of economic implications of aquaculture under climate change. Our results indicate that optimizing aquaculture practices by minimizing impact (this study considers as impact a benthic carbon deposition ≥ 1 g C m^?2 day^?1) will become increasingly difficult under climate change. Moreover, an increasing temperature will produce a poleward shift in sustainability trade‐offs. These findings suggest that future sustainable management strategies and plans will need to account for the effects of climate change across scales. Overall, our results highlight the importance of integrating environmental factors in order to sustainably manage critical natural resources under shifting climatic conditions.