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991.
Tolivia J Navarro A del Valle E Perez C Ordoñez C Martínez E 《Analytical and quantitative cytology and histology / the International Academy of Cytology [and] American Society of Cytology》2006,28(1):43-53
OBJECTIVE: To describe a simple method to achieve the differential selection and subsequent quantification of the strength signal using only one section. STUDY DESIGN: Several methods for performing quantitative histochemistry, immunocytochemistry or hybridocytochemistry, without use of specific commercial image analysis systems, rely on pixel-counting algorithms, which do not provide information on the amount of chromogen present in the section. Other techniques use complex algorithms to calculate the cumulative signal strength using two consecutive sections. To separate the chromogen signal we used the "Color range" option of the Adobe Photoshop program, which provides a specific file for a particular chromogen selection that could be applied on similar sections. The measurement of the chromogen signal strength of the specific staining is achieved with the Scion Image software program. CONCLUSION: The method described in this paper can also be applied to simultaneous detection of different signals on the same section or different parameters (area of particles, number of particles, etc.) when the "Analyze particles" tool of the Scion program is used. 相似文献
992.
del Olmo E Barboza B Ybarra MI López-Pérez JL Carrón R Sevilla MA Boselli C San Feliciano A 《Bioorganic & medicinal chemistry letters》2006,16(10):2786-2790
Several series of dihydrostilbenamide, imidazo[2,1-a]isoindole, pyrimido[2,1-a]isoindole and phthalazinone derivatives were obtained and their vasorelaxant activity was measured on isolated rat aorta rings pre-contracted with phenylephrine (10(-5)M). Some phthalazinones attained, practically, the total relaxation of the organ at micromolar concentrations. For the most potent compound 9h (EC(50)=0.43microM) the affinities for alpha(1A), alpha(1B) and alpha(1D) adrenergic sub-receptors were determined. 相似文献
993.
Griera R Cantos-Llopart C Amat M Bosch J del Castillo JC Huguet J 《Bioorganic & medicinal chemistry letters》2006,16(3):529-531
A synthetic route to a new structural type of potential antibacterials, with a hybrid 3-aryltetrahydroisoquinoline-6,7-diol/N-aryloxazolidinone structure, is reported. The synthesis involves the successive construction of the 3-aryltetrahydroisoquinoline and 4-substituted oxazolidinone moieties, the latter taking advantage of the functionalization at the para position of the aryl group. 相似文献
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997.
Mario Figueroa María del Carmen González Rogelio Rodríguez-Sotres Alejandro Sosa-Peinado Martín González-Andrade Carlos M. Cerda-García-Rojas Rachel Mata 《Bioorganic & medicinal chemistry》2009,17(6):2167-2174
Two new xanthones identified as 15-chlorotajixanthone hydrate (1) and 14-methoxytajixanthone (2) were isolated from an Emericella sp. strain 25379 along with shamixanthone (3) and tajixanthone hydrate (4). The stereostructures of 1 and 2 were elucidated by spectroscopic and molecular modeling methods. The absolute configuration at the stereogenic centers of 1 was established according to CD measurements. In the case of 2, however, the absolute configuration at C-20 and C-25 was designated as S and R, respectively, by Mosher ester methodology. Thereafter, the configuration at C-14 and C-15 of 2 was established as S and S, respectively by comparing the optical rotation and 1H–1H coupling constant experimental values with those obtained through molecular modeling calculations at DFT B3LYP/DGDZVP level of theory for diasteroisomers 2a–2d. The activation of the calmodulin-sensitive cAMP phosphodiesterase (PDE1) was inhibited in the presence of 1–4 in a concentration-dependent manner. The effect of compounds 2 (IC50 = 5.54 μM) and 4 (IC50 = 5.62 μM) was comparable with that of chlorpromazine (CPZ; IC50 = 7.26 μM), a well known CaM inhibitor used as a positive control. The inhibition mechanism of both compounds was competitive with respect to CaM according to a kinetic study. A docking analysis with 2 and 4 using the AutoDock 4.0 program revealed that they interacted with CaM in the same pocket as trifluoropiperazine (TFP). 相似文献
998.
Plasmid replication initiator RepB forms a hexamer reminiscent of ring helicases and has mobile nuclease domains
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D Roeland Boer José A Ruíz‐Masó José R López‐Blanco Alexander G Blanco Mireia Vives‐Llàcer Pablo Chacón Isabel Usón F Xavier Gomis‐Rüth Manuel Espinosa Oscar Llorca Gloria del Solar Miquel Coll 《The EMBO journal》2009,28(11):1666-1678
RepB initiates plasmid rolling‐circle replication by binding to a triple 11‐bp direct repeat (bind locus) and cleaving the DNA at a specific distant site located in a hairpin loop within the nic locus of the origin. The structure of native full‐length RepB reveals a hexameric ring molecule, where each protomer has two domains. The origin‐binding and catalytic domains show a three‐layer α–β–α sandwich fold. The active site is positioned at one of the faces of the β‐sheet and coordinates a Mn2+ ion at short distance from the essential nucleophilic Y99. The oligomerization domains (ODs), each consisting of four α‐helices, together define a compact ring with a central channel, a feature found in ring helicases. The toroidal arrangement of RepB suggests that, similar to ring helicases, it encircles one of the DNA strands during replication to confer processivity to the replisome complex. The catalytic domains appear to be highly mobile with respect to ODs. This mobility may account for the adaptation of the protein to two distinct DNA recognition sites. 相似文献
999.
1. Several hypotheses have been proposed to explain the structure of multi-species assemblages. Among these, abiotic environmental factors and biotic processes are often favoured. Several recent studies examining anuran communities identified environmental factors to be only of minor importance in the composition of leaf-litter and canopy assemblages in pristine forests. Instead, spatial effects and spatially structured environments were considered more important. 2. In this study, we investigated whether these findings could also be confirmed for very heterogeneous stream habitats in the primary rainforest of the Ulu Temburong National Park, Brunei Darussalam. We thus investigated anuran assemblage compositions on 50 stream sites with regard to environmental and spatial influences. 3. Cross-product correlations indicated that both factors (spatial and environmental parameters) determined assemblage composition of anurans. Environment itself may be spatially structured, yet this interrelation did not contribute to the explainable variation of frog community compositions within the study area. 4. Detailed analyses of the environmental parameters with nonmetric multidimensional scaling revealed that community structure was mostly affected by three major environmental characters: stream turbidity, river size and the density of understorey vegetation. Based on these habitat characteristics, we assigned species to three distinct habitat guilds. 5. The results underline the importance of riparian habitat heterogeneity in pristine forests in structuring anuran assemblages. We conclude that different anuran assemblages, that is, leaf litter, canopy and stream communities, follow different assemblage rules and thus are not directly comparable. 相似文献