Agricultural intensification and the collapse of Europe's farmland bird populations.

The populations of farmland birds in Europe declined markedly during the last quarter of the 20th century, representing a severe threat to biodiversity. Here, we assess whether declines in the populations and ranges of farmland birds across Europe reflect differences in agricultural intensity, which arise largely through differences in political history. Population and range changes were modelled in terms of a number of indices of agricultural intensity. Population declines and range contractions were significantly greater in countries with more intensive agriculture, and significantly higher in the European Union (EU) than in former communist countries. Cereal yield alone explained over 30% of the variation in population trends. The results suggest that recent trends in agriculture have had deleterious and measurable effects on bird populations on a continental scale. We predict that the introduction of EU agricultural policies into former communist countries hoping to accede to the EU in the near future will result in significant declines in the important bird populations there.

Effect of S(-) perillic acid on protein prenylation and arterial smooth muscle cell proliferation.

A number of proteins post-translationally modified by the covalent attachment of mevalonate-derived isoprene groups farnesol (FOH) or geranylgeraniol (GGOH), play a role in cell proliferation. For this reason, protein farnesyltransferase (PFTase) and protein geranylgeranyltransferases (PGGTases) I and II have gained attention as novel targets for the development of antiproliferative agents. Monoterpenes [limonene, perillic acid (PA) and its derivatives] have been shown to inhibit cell growth and protein prenylation in cancer cells. In the present study, we evaluated the effect of S(-) PA on diploid rat aorta smooth muscle cell (SMC) proliferation as related to protein prenylation. S(-) PA (1-3.5 mM) decreased, in a concentration-dependent manner, rat SMC proliferation as evaluated by cell counting and DNA synthesis. Morphological criteria and flow cytometry analysis excluded the induction of apoptosis as a potential antiproliferative mechanism of S(-) PA on SMC and confirmed a block of the cell cycle progression in G(0)/G(1) phase. The antiproliferative effect of S(-) PA could not be prevented by the addition of mevalonate, FOH, and GGOH to the culture medium and was independent of cholesterol biosynthesis. Densitometric analysis of fluorographed gels, after sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the cell lysates, further supported that S(-) PA (1-3.5 mM), under the same experimental conditions, concentration-dependently inhibited FOH (up to 70%) and GGOH (up to 70%) incorporation into cellular proteins. We provide evidence that S(-) PA affects protein prenylation, an effect that may contribute to its inhibition of SMC proliferation.

Separation of glyceride positional isomers by silver ion chromatography.

Separation of triglyceride and diglyceride positional isomers by silver ion high-performance liquid chromatography coupled with an evaporative light-scattering detector is described. The triglyceride isomers had a fatty acid composition of CLC and CCL, where C and L were caprylic acid and linoleic acid, respectively. Diglyceride isomers, 1,2(2,3)-diglyceride and 1,3-diglyceride, which contained caprylic acid were separated too. A solvent system based on n-hexane, 2-propanol, ethyl acetate, and acetonitrile with a flow-rate of 0.8 ml/min was developed. Calibration curves of CLC and CCL were achieved with triolein as internal standard. Using this method, the incorporation of linoleic acid onto specific a position of glycerol backbone can be monitored.

Mitochondrial targeting by use of lipid nanocapsules loaded with SV30, an analogue of the small-molecule Bcl-2 inhibitor HA14-1.

Taking advantage from the development of SV30, a new analogue of the pro-apoptotic molecule HA14-1, the aim of this study was to functionally evaluate SV30 and to develop safe nanocarriers for its administration. By using an inversion phase process, 57nm organic solvent-free lipid nanocapsules loaded with SV30 (SV30-LNCs) were formulated. Biological performance of SV30 and SV30-LNCs were evaluated on F98 cells that express Bax and Bcl-2, through survival assays, HPLC, flow cytometry, confocal microscopy and spectral imaging. We observed that SV30 alone or in combination with paclitaxel, etoposide or beam radiation could trigger cell death in a similar fashion to HA14-1. Although partially blocked by Z-VAD-fmk, this effect was coincident to caspase-3 activation. Hence, we established that SV30-LNCs improved SV30 biological activity together with a potentiation of the mitochondrial membrane potential decrease. Interestingly, flow cytometry and confocal analysis indicated that SV30 itself conferred to LNCs improved mitochondrial targeting skills that may present a great interest toward the development of mitochondria targeted nanomedicines.

Synthesis of new optically active propargylic fluorides and application to the enantioselective synthesis of monofluorinated analogues of fatty acid metabolites.

A new approach to obtain optically active unsaturated or polyunsaturated systems with a single fluorine atom in an allylic or propargylic position is reported. Central to this strategy is the high regio- and stereocontrol observed during the fluorination of propargylic alcohols allowing a short and efficient synthesis of 1. Further, simple functional group transformations gave the enals 2 and 3. These three key intermediates were used for the preparation of optically active monofluorinated analogues of fatty acid metabolites.

Synthesis and cytotoxic activity of acetogenin analogues.

A set of 16 new simplified analogues of acetogenins has been designed based on: (i) the replacement of the bis THF moiety of these natural products by an ethylene glycol bis ether unit; (ii) the introduction of different lipophilic side chains (alkyl, aryl, dialkylamino, O-cholesteryl); (iii) the presence of the same terminal isolactone. In vitro cytotoxic activity against L1210 leukemia is reported.

New cytotoxic analogues of annonaceous acetogenins.

A series of new acetogenin analogues incorporating a central catechol moiety instead of the tetrahydrofuran ring(s) have been prepared and tested against L1210 leukemia cells. Although less potent than bullatacinone, which has the same terminal lactone, these compounds display interesting cell cycle effects.

Distribution of tritium labeled 12(S) hydroxy-eicosatetraenoic acid (12-HETE) in the rat.

The in vivo metabolism of 12-(S)-Hydroxy-eicosatetraenoic acid (12-HETE), the end-lipoxygenase product of arachidonic acid in platelets, has been investigated in the rat. Fifty microcuries of 5,6-[3H]-12-HETE (50 Ci/mmol) were injected to anesthetized rats and the radioactivity was followed in plasma. At the end of the experiment, various organs of the animal were removed and the radioactivity attached to them was determined. The label of the plasma plateaued to approximately one third of the initial radioactivity ten minutes after the injection. Among the various organs tested (brain, heart, intestine, kidney, liver, lungs, spleen, testis/uterus) the kidney was far the most active to accumulate 12-HETE and/or its labeled metabolites, and no radioactivity could be detected in urine during the course of the experiment. The analysis of lipid extracts from the various tissues revealed that 12-HETE was not accumulating in its unesterified form but was likely bound to phospholipids. We conclude that, although the label providing from the initial 12-HETE did not completely disappear from plasma, circulating 12-HETE cannot be considered as a circulating marker of cell activation.

Conformations of allylic fluorides and stereoselectivities of their diels-alder cycloadditions.

The preparations of new allylic fluorides from the corresponding alcohols are reported. Conformational analysis is achieved by comparison of experimental NMR measurements with theoretical (B3LYP) calculations of relative energies of conformers and J(H,H) and J(H,F) coupling constants. The Diels-Alder reactions of allylic fluorides are investigated experimentally and theoretically. The stereoselectivities of the reactions were determined by NMR analysis and, in one case, by X-ray crystallography. Theoretical predictions of stereoselectivity based upon transition state modeling provided good agreement with experiment. Theoretical models for allylic fluorides and transition state conformations are reported.

Microwave Spectrum of 1-Cyano-3-fluoro-but-1-ene.

The rotational spectrum of the 1-cyano-3-fluoro-but-1-ene has been recorded with a pulsed-nozzle microwave Fourier transform spectrometer over the range 6-20 GHz. The frequencies were fitted to the Hamiltonian of Watson (A-reduction, I(r) representation). The resulting rotational constants are A = 7493.404(1) MHz, B = 1211.9831(2) MHz, and C = 1096.0908(1) MHz. By comparing the experimental rotational constants with those obtained by ab initio calculations, we found without ambiguity that the stable conformation for the molecule is the one with the fluorine atom lying in the C&bond;CCN plane (CF-eclipsed conformer). Copyright 2000 Academic Press.