[Concomitant, asynchronous and refractory trigeminal and glossopharyngeal neuralgia. Good response to surgical approach in one time]. / Neuralgia del trigémino y del glosofaríngeo concomitantes, asíncronas y refractarias. Buena respuesta al abordaje quirúrgico en un tiempo.

INTRODUCTION: Microvascular decompression (MVD) surgery is the first choice treatment for refractory cranial neuralgia secondary to vascular compression. Simultaneous neuralgia of two cranial nerves is extremely rare. We describe a case of concomitant refractory trigeminal (TN) and glossopharyngeal (GN) neuralgia secondary to neurovascular crossover, treated surgically at the same time. CASE REPORT: 65-year-old woman with right TN (initially V2-V3) since 2004 with regular control with carboxamides. Seventeen years later, paroxysms worsened in V2-V3, also appearing in V1 and in the territory of the right glossopharyngeal nerve (right ear and tonsillar fossa when speaking and swallowing). Cerebral MRI showed significant arterial contact between the superior cerebellar artery (SCA) with the origin of the right V cranial nerve and the antero-inferior cerebellar artery (AICA) with the origin of the right lower CCNN. MVD of both cranial nerves was performed at the same surgical time by means of retrosigmoid craniectomy, releasing the V cranial nerve, in intimate contact with the SCA, and the IX cranial nerve in contact with the right AICA, interposing teflon between them. The patient had an immediate resolution of the trigeminal paroxysms and a dramatic improvement in intensity and frequency of glossopharyngeal paroxysms. Two years after the intervention, de-escalation of neuromodulator treatment continues with good response. CONCLUSION: MVD in simultaneous TN and GN is feasible and can offer a good post-surgical outcome.

TITLE: Neuralgia del trigémino y del glosofaríngeo concomitantes, asíncronas y refractarias. Buena respuesta al abordaje quirúrgico en un tiempo.Introducción. La cirugía de descompresión microvascular (DMV) es el tratamiento de elección de una neuralgia craneal refractaria secundaria a compresión vascular. Las neuralgias simultáneas de dos pares craneales son extremadamente infrecuentes. Describimos un caso con neuralgia concomitante del trigémino (NT) y glosofaríngeo (NG) refractarias y secundarias a cruce neurovascular abordadas quirúrgicamente en un mismo tiempo. Caso clínico. Mujer de 65 años con NT derecho (inicialmente en V2-V3) desde 2004 con control regular con carboxamidas. Diecisiete años después empeoraron los paroxismos en V2-V3, aparecieron también en V1 y en el territorio del nervio glosofaríngeo derecho (oído derecho y fosa amigdalar al hablar y deglutir). La resonancia magnética cerebral mostró contacto arterial significativo entre arteria cerebelosa superior (ACS) con origen del V par craneal derecho y de la arteria cerebelosa antero-inferior (AICA) con el origen de pares craneales bajos derechos. Se realizó DMV de ambos pares craneales en un mismo tiempo quirúrgico mediante craniectomía retrosigmoidea, y se procedió a la liberación del V par craneal, en contacto íntimo con la ACS, y del IX par craneal en contacto con la AICA derecha, para lo que se puso teflón entre ellas. La paciente tuvo una resolución inmediata de los paroxismos trigeminales y una mejoría considerable en intensidad y frecuencia de los glosofaríngeos. A los 2 años de la intervención continúa la desescalada de tratamiento neuromodulador con buena respuesta. Conclusión. La DMV en la NT y NG simultáneas es factible y puede ofrecer un buen resultado posquirúrgico.

Occurrence of antibiotics in Lettuce (Lactuca sativa L.) and Radish (Raphanus sativus L.) following organic soil fertilisation under plot-scale conditions: Crop and human health implications.

Recent studies have demonstrated the crop uptake of antibiotics (ABs) from soils treated with AB-carrying fertilisers. However, there is a lack of plot-scale studies linking their effects at the agronomic and metabolomic/transcriptomic level to their impact on human health. This paper assesses the plant uptake of 23 ABs following two productive cycles of lettuce and radish cropped with sewage sludge, pig slurry, the organic fraction of municipal solid waste, or chemical fertilisation under plot-scale conditions (32 plots spanning 3-10 m2 each). AB uptake by plants depended on both the vegetable and the AB class and was higher in radish than in lettuce edible parts. Levels ranged from undetectable to up to 76 ng/g (fresh weight). Repetitive organic fertilisation resulted in an increase in the concentration of ABs in lettuce leaves, but not in radish roots. Significant metabolomic and transcriptomic changes were observed following soil fertilisation. Nevertheless, a human health risk assessment indicates that the occurrence of ABs in lettuce or radish edible parts does not pose any risk. To our knowledge, this is the first holistic plot-scale study demonstrating that the use of organic fertilisers containing ABs is safe for crop security and human health.

Evaluation of antibiotic mobility in soil associated with swine-slurry soil amendment under cropping conditions.

Interest in identifying pools of antibacterial-resistance genes has grown over the last decade, with veterinary antibiotics (VAs) receiving particular attention. In this paper, a mesoscale study aimed at evaluating the vertical transport of common VAs-namely, fluoroquinolones, tetracyclines, sulfonamides, and lincosamides in agricultural soil subjected to drip irrigation-was performed under greenhouse conditions. Accordingly, leachates of cropped and uncropped soil, amended with swine-slurry leading to 19-38 µg kg(-1) (dry mass) antibiotics in the soil, were analyzed over the course of the productive cycle of a lettuce (42 days) with three sampling campaigns (N = 24). High lincomycin (LCM) concentrations (30-39 µg L(-1)) were detected in the leachates collected from the swine-slurry-amended soil. The highest LCM mass recovered in the leachates (30.1 ± 1.63 %) was obtained from cropped experimental units. In addition, the LCM leaching constant and its leaching potential as obtained from the first-order model were higher in the leachates from the cropped experimental units. Lower concentrations of sulfadimethoxine were also detected in leachates and in soil. Enrofloxacin and oxytetracycline occurred only in soil, which is consistent with high soil interaction.

Development of quantitative RNA biomarkers for detecting dioxin-like and estrogenic pollutants in Costa Rican native fish species.

Monitoring the environmental impact on native species is crucial for the correct management of tropical ecosystems. The Costa Rican fish Parachromis dovii (Cichlidae) and Poecilia gillii (Poecillidae) were used as sentinel species for freshwater bodies under considerable pressure by intensive agriculture Cichlidae development. Suitable qRT-PCR probes for the quantification of hepatic mRNA levels of two stress-related genes--vitellogen in (estrogenic effects) and cytochrome P4501A(CYP1A, dioxin-like compounds)--for both species were designed and validated in experimental treatments with model effectors (17beta-estradiol and beta-naphtoflavone, respectively), demonstrating their usefulness as markers of exposure to these two kinds of pollutants. Analysis of fish transplanted across pesticide contaminated sites near Palo Verde National Park, Pacific Coast of Costa Rica did show significant changes on hepatic Cyp1A in both species. In P. dovii, Cyp1A levels were enhanced in Barbubal and in the impacted Cabuyo sites in the rainy season whereas in P. gillii fish Cyp1A transcripts were down-regulated differently across rainy and dry seasons. Vitellogen in mRNA levels in P. gillii varied between males and females with males showing always low values which indicated no estrogenic effects. Within females, vitellogenin levels varied over 100,000 fold depending on their maturation stage, further demonstrating the ability of the method to monitor changes (natural or induced) in the reproductive system of the fish.

Advanced UV/H2O2 oxidation of deca-bromo diphenyl ether in sediments.

Removal of BDE-209 from contaminated sediments by UV/H2O2 treatment was investigated under different reaction conditions (different UV irradiance and H2O2 concentrations). After 10h of UV/H2O2 treatment, 90% of BDE-209 was removed with a half-life time (t1/2) of 3.5h and a kinetic constant (k) of 0.22 h(-1). Possible formation of OH-PBDEs and debrominated polybromodiphenyl ethers was investigated by GC-MS and LC-MS/MS. None of the abovementioned BDE-209 by-products was found after 2.5, 5.5 and 10h of UV/H2O2 treatment. Toxicity experiments carried out with zebrafish embryos exposed to the sediment before and after the UV/H2O2 treatment did not show any morphological or behavioural alterations, suggesting that no putative debrominated or oxidation products were originated by the treatment in concentrations high enough to elicit significant toxic effects in zebrafish embryos.

Estrogenic effects of nonylphenol and octylphenol isomers in vitro by recombinant yeast assay (RYA) and in vivo with early life stages of zebrafish.

Commercial OP and NP are complex isomer mixtures that can be individually present in the environment, showing different estrogenic potencies. The aims of this study were to establish the estrogenic potency of some AP isomers in comparison to the commercial NP (cNP) mixture in vitro and to investigate in vivo their possible effects during the embryo and larval development of zebrafish. An in vitro estrogen receptor-based recombinant yeast assay was used to test the estrogenicity of specific AP isomers (22-OP, 33-OP, 22-NP, 33-NP and 363-NP) and cNP. The EC50 was in the range of 0.6-7.7 mg/L. Both OP isomers and 363-NP exhibited higher estrogenic activity than cNP. For in vivo experiments, one-day postfertilisation (dpf) embryos were exposed to cNP (50, 250 and 500 µg/L), 363-NP and 33-OP (50 µg/L), 17ß-estradiol (100 ng/L) and DMSO (0.01% v/v) for 4weeks. After exposure fish were maintained for 2 weeks in clean water in order to evaluate a possible recovery. Fish of groups exposed to cNP and 363-NP were the last to hatch. Histological alterations were not observed after 7, 28 or 42 dpf. Exposure to 33-OP increased transcriptional levels of erα, vtg and cyp19a1b genes. However, transcriptional response in E2 exposure was observed at later stages and with higher fold induction levels. Exposure to cNP decreased levels of erα whereas increased levels of rxrγ and cyp19a1b. Exposure to 363-NP did not cause changes in transcriptional levels of studied genes. The differences in response of the OP isomer compared to the NP isomer in zebrafish could be related to the rapid decay in concentration of the latter.

Supplemental leucine and isoleucine affect expression of cationic amino acid transporters and myosin, serum concentration of amino acids, and growth performance of pigs.

Leucine (Leu) participates in the activity of cationic amino acid (aa) transporters. Also, branched-chain aa [Leu, isoleucine (Ile), and valine (Val)] share intestinal transporters for absorption. We conducted an experiment with 16 young pigs (body weight of about 16 kg) to determine whether Leu and Ile affect expression of aa transporters b(0,+) and CAT-1 in the jejunum and expression of myosin in muscle, as well as serum concentration of essential aa, and growth performance in pigs. Dietary treatments were: wheat-based diets fortified with Lys, Thr, and Met; basal diet plus 0.50% Leu; basal diet plus 0.50% Ile, and basal diet plus 0.50% Leu and 0.50% Ile. After 28 days, the pigs were sacrificed to collect blood, jejunum, and semitendinosus and longissimus muscle samples. The effects of single and combined addition of Leu and Ile were analyzed. Leu alone or combined with Ile significantly decreased daily weight gain and reduced feed conversion. Leu and Ile, alone or in combination, significantly decreased expression of b(0,+) and significantly increased CAT-1. Ile alone or combined with Leu significantly decreased myosin expression in semitendinosus and significantly decreased it in longissimus muscle. Leu alone significantly decreased Lys, Ile and Thr serum concentrations; Ile significantly decreased Thr serum concentration; combined Leu and Ile significantly decreased Thr and significantly increased Val serum concentration. We conclude that dietary levels of Leu and Ile affect growth performance, expression of aa transporters and myosin, and aa serum concentrations in pigs.

Chemical characterization of organic microcontaminant sources and biological effects in riverine sediments impacted by urban sewage and pulp mill discharges.

The Biobío River basin is highly impacted by a variety of anthropogenic activities such as pulp mills and urban wastewaters subjected to different treatment processes. This work assesses for the first time, the contamination source and biological effects (estrogenic and dioxin-like activities) in the river basin by the determination of 45 organic microcontaminants in seven sediment samples. Pressurized solvent extraction combined with two-dimensional comprehensive gas chromatography coupled to time of flight mass spectrometry was employed for this purpose. The organic microcontaminants identified comprise monoterpenes, sesquiterpenes, diterpenes, ionones, lineal alkyl benzenes, polycyclic aromatic hydrocarbons, musk fragrances, sterols and phathalate esters. The presence of pine and eucalyptus pulp mill effluents increased the abundance of resin-derived neutral compounds and monoterpenes respectively. A principal component analysis showed that the Biobío River basin was impacted by domestic wastewater treatment plants (WWTPs), pine or eucalyptus Kraft pulp mills and pyrolytic and pyrogenic processes. Finally, the recombinant yeast assays showed that the presence of estrogenic and dioxin-like activity was mostly located in sediments impacted by domestic WWTP effluents.

Enhanced offspring production in Daphnia magna clones exposed to serotonin reuptake inhibitors and 4-nonylphenol. Stage- and food-dependent effects.

Risk assessment of emerging pollutants requires the development of bioassays able to detect and understand novel mechanisms of action. This study tested the hypothesis that the increase of offspring production in Daphnia magna induced by certain pollutants may be mediated through different mechanisms, depending on development stages, clones and food rations The study included two selective serotonin reuptake inhibitors (SSRIs), fluoxetine and fluvoxamine, and the detergent metabolite 4-nonylphenol. Organisms were exposed from birth to adulthood or only during adulthood at low and high food ration levels. Results indicated that low exposure levels of the three studied substances increased offspring production and/or juvenile developmental rates similarly for all studied clones, but the responses differed among life-stages and food rations. When individuals were exposed to the studied chemicals from birth, enhanced offspring production per female was observed only at low and intermediate food rations. On the contrary, when exposures started in gravid females most treatments increased offspring production. Results obtained with SSRIs support previous findings, where it was stated that these compounds may amplify serotoninergic signaling in D. magna. Nonylphenol effects may be related to the reported alteration of this compound in Daphnia ecdysteroid metabolism. Further investigations are necessary to resolve the biochemical mechanism of SSRI and nonylphenol enhancing offspring production.

Differential expression of thiamine biosynthetic genes in yeast strains with high and low production of hydrogen sulfide during wine fermentation.

AIMS: Release of hydrogen sulfide by fermenting yeast is a potential problem in wine production, because of its strong organoleptic impact. To identify the genetic determinants of sulfide production, we compared the transcriptomes of two wine yeast strains with similar oenological properties, but with very different levels of sulfide production, UDC522 (high sulfide producer) and P29 (low producer). METHODS AND RESULTS: Oenological microfermentations were sampled at the peak production of sulfide. Transcription profiles of the two strains were analysed by three methods, a cDNA-based array, an oligonucleotide-based array and qRT-PCR analysis of selected transcripts. Less than 10% of yeast genes showed significant differences between the two strains. High sulfide production correlated with a general overexpression of thiamine biosynthesis genes, whereas genes linked to the catabolism of sulfur-containing compounds (like amino acids) showed no significant expression differences between both strains. CONCLUSIONS: Our data suggest a relationship between the thiamine biosynthetic pathway and sulfide production during wine fermentation. SIGNIFICANCE AND IMPACT OF THE STUDY: This study provides a first hint which indicates that for some yeast strains, biosynthesis of thiamine (and perhaps of other sulfur-containing compounds) may be more relevant than the general nitrogen metabolism in explaining sulfide production by some yeast strains during vinification, defining new targets for genetic improvement of wine yeast strains.

Detection of estrogenic activity from kraft mill effluents by the yeast estrogen screen.

Estrogenic activity of kraft pulp mill effluents (P. radiata, E. globulus and mixed -50% E. globulus and 50% P. radiata) was evaluated by the yeast estrogen screen assay. The estrogenic activity values were relatively low, ranking between 1.475 and 0.383 ng/L of EE2 eq. (Estrogenic equivalent of 17 alpha-ethynylestradiol), where the highest value corresponds to the E. globulus effluent and the lowest value to the P. radiata effluent. Analysis by solid phase extraction (SPE) and gas chromatography-mass spectrometry (GC-MS) of chemical compounds present in all three effluents detected at least five major groups of organic compounds, corresponding to fatty acids, hydrocarbons, phenols, sterols and triterpenes. Comparison of analytical and biological data suggests that sterols could be the cause of the estrogenic activity in the evaluated effluent.

Blood biomarkers and contaminant levels in feathers and eggs to assess environmental hazards in heron nestlings from impacted sites in Ebro basin (NE Spain).

Blood biomarkers and levels of major pollutants in eggs and feathers were used to determine pollution effects in nestlings of the Purple Heron Ardea purpurea and the Little Egret Egretta garzetta, sampled on three Ebro River (NE Spain) areas: a reference site, a site affected by the effluents of a chlor-alkali industry and the river Delta. The two impacted heron populations showed mutually different pollutant and response patterns, suggesting different sources of contamination. In the population nesting near the chlor-alkali plant, elevated levels of hexachlorobenzene (HCB) and polychlorobiphenyls (PCBs) in eggs, and mercury in feathers in A. purpurea chicks were related with reduced blood antioxidant defenses and increased levels of micronuclei. In Ebro Delta, high levels of plasmatic lactate dehydrogenase in A. purpurea chicks and high frequency of micronuclei in blood of both species were tentatively associated with intensive agricultural activities taking place in the area. These results provide the first evidence of a biological response in heron chicks to the release of pollutants at a chlor-alkali plant.

Clinical response to ertapenem in severe community-acquired pneumonia: a retrospective series in an elderly population.

To evaluate in routine hospital practice the clinical response to ertapenem in comparison with other parenteral antibiotics in the treatment of community-acquired pneumonia (CAP), clinical records from patients with severe CAP treated with ertapenem from July 2002 to June 2006 in seven Spanish hospitals were retrospectively reviewed. Patients were classified according to the Pneumonia Severity Index (PSI). Each ertapenem-treated patient was matched with two patients in the same hospital treated with other antibiotics, according to age (difference 76 years). Comorbidities were present in 193 patients (95.5%). No differences were found in median hospital stay (7 days for ertapenem vs. 10 days for comparators, p 0.066). A slightly higher clinical response rate was obtained for ertapenem vs. comparators (88.7% vs. 77.1%; p 0.0465; OR 2.25; 95% CI 0.99-5.12), with significant differences in clinical response in patients coming from nursing homes (95.8% ertapenem vs. 63.8% comparators; p 0.0034) but not in non-institutionalized patients (85.4% ertapenem vs. 84.5% comparators; p 0.929). The higher clinical response to ertapenem vs. comparators in severe CAP was due to its significantly higher efficacy in healthcare-associated CAP in patients coming from nursing homes.

The different (sur)faces of Rap1p.

The DNA-binding protein Rap1p fulfills many different functions in the yeast cell. It targets 5% of the promoters, acting both as a transcriptional activator and as a repressor, depending on the DNA sequence context. In addition, Rap1p is an essential structural component of yeast telomeres, where it contributes to telomeric silencing. Here we review the evidence indicating that Rap1p function is modulated by the precise architecture of the its binding site and its surroundings: long tracts of telomeric repeats for telomeric functions, specific sequences and orientation for maximal transcriptional activation, and specific DNA recognition sequences for complementary factors in other cases. Many of these functions are probably related to chromatin organization around Rap1p DNA binding sites, resulting from the very tight binding of Rap1p to DNA. We propose that Rap1p alters its structure to bind to different versions of its DNA binding sequence. These structural changes may modulate the function of Rap1p domains, providing different interacting surfaces for binding to specific co-operating factors, and thus contributing to the diversity of Rap1p function.

Genetic analysis of the karyotype instability in natural wine yeast strains.

Yeast strains isolated from the wild may show high rates of changes in their karyotypes during vegetative growth. We analysed over 500 karyotypes from mitotic and meiotic derivatives of strain DC5, which has a chromosome rearrangement rate of 8.2 x 10(-3) changes/generation. About 70% of the meiotic derivatives of DC5 had low rearrangement rates, with an average of 5.8 x 10(-4) changes/generation, suggesting that karyotype instability behaved as a dominant phenotype. Diploid derivatives with low karyotype variability in mitosis also had low rates of chromosomal rearrangement during meiosis, suggesting that the two phenotypes may be linked. DC5 and some of its meiotic derivatives (both with high and low karyotype variability) had chromosome XII hypervariable bands. Their distribution among the meiotic products indicates that they are not indicators for genetic instability. To our knowledge, data in this paper are the first to indicate that karyotypically unstable yeast strains may give stable progeny at high rates. Understanding of the relevant mechanism(s) may allow the design of genetic strategies to stabilize karyotypes from natural and/or industrial wine yeasts with unacceptable karyotype rearrangement rates.

Enantioselective synthesis of fluorinated alpha-amino acids and derivatives in combination with ring-closing metathesis: intramolecular pi-stacking interactions as a source of stereocontrol.

[reaction: see text]. Hydride reduction of C=N bonds stereocontrolled by intramolecular pi-stacking interactions of 1-naphthylsulfinyl and N-aryl groups, nonoxidative Pummerer rearrangement, and ring-closing metathesis are efficiently combined in a highly stereoselective entry to enantiomerically pure cyclic and acyclic fluorinated beta-amino alcohols and alpha-amino acid derivatives, respectively.

Monitoring of endocrine disruptors in surface waters by the yeast recombinant assay.

Endocrine disruptors exert physiological effects at very low concentrations. Surface waters present often a mixture of high concentrations of low-potency disruptors and low amounts of very powerful ones, making their chemical analysis complicated and expensive. We developed a recombinant yeast assay (RYA) for estrogenic compounds using 96-well microtiter plates. This assay is based on three yeast strains, transformed with self-propagating plasmids. One strain contains an expression plasmid for the human estrogen hormone receptor and an appropriate reporter; it detects estrogenic and antiestrogenic activities. The two other yeast strains, one expressing the human progesterone receptor and a second based on the yeast activator Gal4p, served to analyze the nature of antiestrogenic activities. We applied this technique to water samples from two tributaries on the Llobregat river (NE Spain) as well as from four sewage treatment plants discharging on them. Our results indicate that the efficiency of sewage treatment plants for eliminating estrogenic compounds varied notably, being in at least one case completely inefficient. We also observed a prevalence of an inhibitory activity all through the two rivers; this inhibition was hormone specific. These results were consistent to previously obtained chemical analyses of the same samples, although chemical and in vivo analyses showed rather different levels of sensitivity for some compounds. Our findings demonstrate the utility of the yeast recombinant assay for analyzing complex natural samples; at the same time, they stress the necessity of a panel of different yeast systems to adequately describe endocrine-disruptor activities.

Alternative mechanisms of transcriptional activation by Rap1p.

Single Rap1p DNA-binding sites are poor activators of transcription of yeast minimal promoters, even when fully occupied in vivo. This low efficiency is due to two independent repression mechanisms as follows: one that requires the presence of histones, and one that requires Hrs1p, a component of the RNA polymerase II mediator complex. Both repression mechanisms were greatly reduced for constructs with tandemly arranged sites. In these constructs, UASrpg sequences (ACACCCATACATTT) activated better than telomere-like sequences (ACACCCACACACCC) in an orientation-dependent manner. Both mutations in the SWI/SNF complex and a deletion of amino acids 597--629 of Rap1p (Tox domain) decreased synergistic effects of contiguous telomeric sites. Conversely, deletion of amino acids 700--798 of Rap1p (Sil domain) made UASrpg and telomeric sites functionally indistinguishable. We propose that the Sil domain masks the main transactivation domain of Rap1p in Rap1p-telomere complexes, where the Tox domain behaves as a secondary activation domain, probably by interacting with chromatin-remodeling complexes. Rap1p DNA-binding sites in ribosomal protein gene promoters are mainly UASrpg-like; their replacement by telomeric sequences in one of these promoters (RPS17B) decreased transcription by two-thirds. The functional differences between UASrpgs and telomeric sequences may thus contribute to the differential expression of Rap1p-regulated promoters in vivo.

Benzyl derivatives of 2,1,3-benzo- and benzothieno[3,2-a]thiadiazine 2,2-dioxides: first phosphodiesterase 7 inhibitors.

The synthesis of a new family of benzyl derivatives of 2,1,3-benzo- and benzothieno[3,2-a]thiadiazine 2,2-dioxides was achieved. The biological data revealed the first heterocyclic family of compounds with PDE 7 inhibitory properties appearing to be a new objective for the treatment of T-cell-dependent disorders. The IC(50) values or percent inhibition values of the compounds against PDE 7 were calculated by testing them against human recombinant PDE 7 expressed in S. cerevisiae. In this expression system the only cyclic nucleotide hydrolyzing activity present in cell extracts corresponded to human PDE 7. Isoenzyme selectivity PDE 7 versus PDE 4 and PDE 3 was also measured. Considering simultaneously inhibition of the three different isoenzymes, monobenzyl derivatives 15 and 23 showed interesting PDE 7 potency (around 10 microM); although not statistically significant, a trend toward selectivity with respect to PDE 3 and PDE 4 was obtained. Benzothiadiazine 16, although less potent at PDE 7 (IC(50) = 25 microM), also showed a trend of selectivity toward PDE 3 and PDE 4. These compounds are considered the best leads for further optimization.

Functional divergence between the half-sites of the DNA-binding sequence for the yeast transcriptional regulator Rap1p.

The yeast transcriptional regulator Rap1p binds to the DNA consensus sequence ACACCCAYACAYYY. We have previously shown that DNA-binding sites in which all four Y (Y=T or C) positions were Ts (UASrpg sequences) synergized more efficiently to activate transcription than sequences in which all Ys were Cs (telomere sequences) [F.-Z. Idrissi, J. Fernández-Larrea and B. Piña (1998) J. Mol. Biol. 284, 925-935]. Here we provide evidence that the DNA consensus sequence for Rap1p behaves as a combination of two ACAYYY half-sites with different functionality, the presence of Ts in the second half-site being the determinant for the transcriptional behaviour of the UASrpg sequences. DNA structure in the different complexes with Rap1p varied from being relatively uniform to appear rather distorted, this also being dependent on the presence of Ts in the second half-site. These distortions did not cause sharp bends or kinks in the DNA molecule. Computer analysis suggests that high-affinity binding of Rap1p to UASrpg sequences requires a rearrangement of the C-terminal Myb domain of the protein. We propose that the structural alterations in Rap1p-DNA complexes, both in the DNA and in the protein, affect the transcription potential of the complex in an allosteric manner. We also propose that the dimeric nature of the Rap1 DNA-binding domain is a key structural feature that explains the disparate functions of its DNA-binding sites in vivo.