ALBERT

Description: Evidence is accumulating that species’ responses to climate changes are best predicted by modelling the interaction of physiological limits, biotic processes and the effects of dispersal-limitation. Using commercially harvested blacklip ( Haliotis rubra ) and greenlip abalone ( H. laevigata ) as case studies, we determine the relative importance of accounting for interactions among physiology, metapopulation dynamics and exploitation in predictions of range (geographical occupancy) and abundance (spatially explicit density) under various climate change scenarios. Traditional correlative ecological niche models (ENM) predict that climate change will benefit the commercial exploitation of abalone by promoting increased abundances without any reduction in range size. However, models that account simultaneously for demographic processes and physiological responses to climate-related factors result in future (and present) estimates of area of occupancy and abundance that differ from those generated by ENMs alone. Range expansion and population growth are unlikely for blacklip abalone because of important interactions between climate-dependent mortality and metapopulation processes; in contrast, greenlip abalone should increase in abundance despite a contraction in area of occupancy. The strongly non-linear relationship between abalone population size and area of occupancy has important ramifications for the use of ENM predictions that rely on metrics describing change in habitat area as proxies for extinction risk. These results show that predicting species’ responses to climate change often require physiological information to understand climatic range determinants, and a metapopulation model that can make full use of this data to more realistically account for processes such as local extirpation, demographic rescue, source-sink dynamics and dispersal-limitation. This article is protected by copyright. All rights reserved.

Description: Second-order rate constants were determined for the oxidation of 27 alcohols (R 1 R 2 CHOH) by a carbocationic oxidizing agent, 9-phenylxanthylium ion, in acetontrile at 60 °C. Alcohols include open-chain alkyl, cycloalkyl, and unsaturated alcohols. Kinetic isotope effects for the reaction of 1-phenylethanol were determined at three H/D positions of the alcohol (KIE α-D  = 3.9, KIE β-D3  = 1.03, KIE OD  = 1.10). These KIE results are consistent with those we previously reported for the 2-propanol reaction, suggesting that these reactions follow a hydride-proton sequential transfer mechanism that involves a rate-limiting formation of the α-hydroxy carbocation intermediate. Structure–reactivity relationship for alcohol oxidations was deeply discussed on the basis of the observed structural effects on the formation of the carbocationic transition state (C δ+ OH). Efficiencies of alcohol oxidations are largely dependent upon the alcohol structures. Steric hindrance effect and ring strain relief effect win over the electronic effect in determining the rates of the oxidations of open-chain alkyl and cycloalkyl alcohols. Unhindered secondary alkyl alcohols would be selectively oxidized in the presence of primary and hindered secondary alkyl alcohols. Strained C 7 C 11 cycloalkyl alcohols react faster than cyclohexyl alcohol, whereas the strained C 5 and C 12 alcohols react slower. Aromatic alcohols would be efficiently and selectively oxidized in the presence of aliphatic alcohols of comparable steric requirements. This structure–reactivity relationship for alcohol oxidations via hydride-transfer mechanism is hoped to provide a useful guidance for the selective oxidation of certain alcohol functional groups in organic synthesis. Copyright © 2011 John Wiley & Sons, Ltd. Second-order rate constants were determined for the hydride-transfer oxidation of 27 alcohols by 9-phenylxanthylium ion in acetonitrile. Structure–reactivity relationship was discussed and is hoped to provide a useful guidance for the selective oxidation of certain alcohol functional groups in organic synthesis.

Description: The reaction of Ni II with a tetra-benzoate pyrene ligand produces a 3D porous framework based on infinite 1D Ni II chains. The Ni II –O connectivity and the formation of a hydroxo-bridge (μ 3 -OH) responsible for the connection of the central Ni II atoms within the 1D Ni II –(μ 3 -OH) 2 –Ni II chains can be straightforwardly compared with the Ti IV –O–Ti IV connectivity seen in TiO 2 . The arrangement of the TBAPy ligand around the 1D rutile-based chains leads in the generation of a porous framework with two distinct types of pores; based on the chemistries of these two types of pores, one can be labelled as hydrophobic and the other as hydrophilic. The use of different activation methods results in the generation of either a porous framework free of guest molecules or a completely solvent-free material, in which the terminal H 2 O molecules bound to Ni II were removed, leading thus to a framework with open Ni II sites. CO 2 isotherms collected on both frameworks at 195 K and one barshowed type I isotherms characteristic of microporous materials (BET surface areas for: guest-free framework: 257(3) m 2 · g –1 ; solvent-free framework: 362(2) m 2 · g –1 ). The affinity of both networks at zero coverage for both CO 2 and CH 4 was found to be greater when the unsaturated Ni II sites are available within the void space.

Description: 2-(4-amino-3-methylphenyl)-5-fluorobenzothiazole (5F203, NSC 703786) lysylamide belongs to a novel mechanistic class of antitumor agents. It elicits activity against ovarian, breast, kidney and colorectal cancer models. In sensitive breast cancer cells, 5F203 activates aryl hydrocarbon receptor (AhR) signaling. Herein, we evaluate the role of AhR in 5F203 activity in two ovarian cancer cell lines: IGROV-1 (sensitive to 5F203), SKOV-3 (resistant to this agent). In addition, cancer cells have been isolated from ascites fluid of ovarian cancer patients; sensitivity to 5F203 and concurrent AhR signal transduction has been examined in ascites-isolated ovarian cancer patients' cells. 5F203 induced enhanced CYP1A1 expression, AhR translocation and ROS formation in IGROV-1 cells and ascites-isolated ovarian cancer cells that were sensitive to 5F203. In IGROV-1 cells 5F203-induced ROS formation was accompanied by JNK, ERK and P38MAPK phosphorylation, DNA damage and cell cycle arrest prior to apoptosis. In contrast, 5F203 failed to induce CYP1A1 expression, AhR translocation or oxidative stress in 5F203-resistant SKOV-3 cells, or in ovarian cancer ascites cells inherently resistant to this agent. We propose that AhR may represent a new molecular target in the treatment of ovarian tumors and 5F203 may exemplify a potential novel treatment. Furthermore, putative biomarkers of sensitivity to this agent have been identified. J. Cell. Biochem. © 2013 Wiley Periodicals, Inc.

Description: When isolated mitochondria from the yeast Saccharomyces cerevisiae oxidize respiratory substrates in the absence of phosphate and ADP, the yeast mitochondrial unselective channel, also called the yeast permeability transition pore (yPTP), opens in the inner membrane dissipating the electrochemical gradient. ATP also induces yPTP opening. yPTP opening allows mannitol transport into isolated mitochondria of laboratory yeast strains, but mannitol is not readily permeable through the yPTP in an industrial yeast strain, Yeast Foam. The presence of oligomycin, an inhibitor of ATP synthase, allowed for respiration-induced mannitol permeability in mitochondria from this strain. Potassium (K + ) had varied effects on the respiration-induced yPTP depending on the concentration of the respiratory substrate added. At low respiratory substrate concentrations K + inhibited respiration-induced yPTP opening, while at high substrate concentrations this effect diminished. However, at the high respiratory substrate concentrations, the presence of K + partially prevented phosphate inhibition of yPTP opening. Phosphate was found to inhibit respiration-induced yPTP opening by binding a site on the matrix space side of the inner membrane in addition to its known inhibitory effect of donating protons to the matrix space to prevent the pH change necessary for yPTP opening. The respiration-induced yPTP was also inhibited by NAD, Mg 2+ , NH 4 + , or the oxyanion vanadate polymerized to decavanadate. The results demonstrate similar effectors of the respiration-induced yPTP as those previously described for the ATP-induced yPTP and reconcile previous strain-dependent differences in yPTP solute selectivity. This article is protected by copyright. All rights reserved.

Description: The Vulnerable (IUCN) whale shark spans warm and temperate waters around the globe. However, their present-day and possible future global distribution has never been predicted. Using 30 years (1980-2010) of whale shark observations recorded by tuna purse-seiners fishing in the Atlantic, Indian and Pacific Oceans, we applied generalized linear mixed-effects models to test the hypothesis that similar environmental covariates predict whale shark occurrence in all major ocean basins. We derived global predictors from satellite images for chlorophyll a and sea surface temperature, and bathymetric charts for depth, bottom slope and distance to shore. We randomly generated pseudo-absences within the area covered by the fisheries, and included fishing effort as an offset to account for potential sampling bias. We predicted sea surface temperatures for 2070 using an ensemble of five global circulation models under a no climate-policy reference scenario, and used these to predict changes in distribution. The full model (excluding standard deviation of sea surface temperature) had the highest relative statistical support ( w AIC c = 0.99) and explained ~ 60% of the deviance. Habitat suitability was mainly driven by spatial variation in bathymetry and sea surface temperature among oceans, although these effects differed slightly among oceans. Predicted changes in sea surface temperature resulted in a slight shift of suitable habitat towards the poles in both the Atlantic and Indian Oceans (~ 5 ºN and 3‒8 ºS, respectively) accompanied by an overall range contraction (2.5‒7.4% and 1.1‒6.3%, respectively). Predicted changes in the Pacific Ocean were small. Assuming that whale shark environmental requirements and human disturbances (i.e., no stabilization of greenhouse gas emissions) remain similar, we show that warming sea surface temperatures might promote a net retreat from current aggregation areas and an overall redistribution of the species. This article is protected by copyright. All rights reserved.

Description: Questions Can the model performance of the landscape reconstruction algorithm (LRA) for small forest hollows be validated through comparison to inventory-based vegetation reconstructions from the last 150 yrs? Does the application of LRA and the comparison to historical data enhance interpretation of the pollen record? Location Denmark. The Gribskov-Ostrup small forest hollow (56°N, 12°20′ E, 44 m a.s.l.) in the forest of Gribskov, eastern Denmark. Methods Pollen analysis was carried out on a small forest hollow, and LRA used to derive pollen-based quantitative estimates of past vegetation. Historical forest inventory data and maps were used to reconstruct the vegetation within three different circles around the hollow (20, 50 and 200 m ring widths) for five time periods during the last 150 yrs. The results of the two approaches were compared in order to evaluate model performance, and the LRA-based reconstruction used to describe how the model changes interpretation of vegetation development during the last ca. 6500 yrs compared to the use of pollen percentages alone. Results Distance-weighted inventory-based reconstructions within 200 m of the hollow's edge provide the best match with the LRA-modelled vegetation. Precise validation of the model is not possible due to insufficient historical data, but the comparison indicates that the LRA reconstruction for Gribskov tends to (1) underestimate tree cover and overestimate open areas, (2) give a too high representation of on-site pollen types, (3) give an underestimation of Fagus and (4) a small overestimation of Quercus and Corylus . Despite these uncertainties, application of the LRA model shows a higher degree of openness than would be apparent from the uncorrected pollen diagram, and makes it possible to attempt to distinguish changes at the local scale from regional vegetation changes, thus giving a clearer picture of the vegetation changes at the site. Conclusions We demonstrate that the estimates of the LRA model applied to pollen data from small forest hollows can be compared with small-scale historical data to evaluate model performance. Landscape Reconstruction Algorithm-modelled vegetation showed the best match with distance-weighted inventory-based vegetation within a 200 m circle around the small hollow. Applying the model further back in time allowed reconstruction of local vegetation dynamics which are not detectable at the regional scale, such as a very early local occurrence of Fagus sylvatica around the site.