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921.
Mitcheell Maestre‐Martínez Katja Haupt Frank Edlich Piotr Neumann Christoph Parthier Milton T. Stubbs Gunter Fischer Christian Lücke 《Journal of molecular recognition : JMR》2011,24(1):23-34
The Bcl‐2 inhibitor FKBP38 is regulated by the Ca2+‐sensor calmodulin (CaM). Here we show a hitherto unknown low‐affinity cation‐binding site in the FKBP domain of FKBP38, which may afford an additional level of regulation based on electrostatic interactions. Fluorescence titration experiments indicate that in particular the physiologically relevant Ca2+ ion binds to this site. NMR‐based chemical shift perturbation data locate this cation‐interaction site within the β5–α1 loop (Leu90–Ile96) of the FKBP domain, which contains the acidic Asp92 and Asp94 side‐chains. Binding constants were subsequently determined for K+, Mg2+, Ca2+, and La3+, indicating that the net charge and the radius of the ion influences the binding interaction. X‐ray diffraction data furthermore show that the conformation of the β5–α1 loop is influenced by the presence of a positively charged guanidinium group belonging to a neighboring FKBP38 molecule in the crystal lattice. The position of the cation‐binding site has been further elucidated based on pseudocontact shift data obtained by NMR via titration with Tb3+. Elimination of the Ca2+‐binding capacity by substitution of the respective aspartate residues in a D92N/D94N double‐substituted variant reduces the Bcl‐2 affinity of the FKBP3835–153/CaM complex to the same degree as the presence of Ca2+ in the wild‐type protein. Hence, this charge‐sensitive site in the FKBP domain participates in the regulation of FKBP38 function by enabling electrostatic interactions with ligand proteins and/or salt ions such as Ca2+. Copyright © 2010 John Wiley & Sons, Ltd. 相似文献
922.
Reina M Ruiz-Mesia W Ruiz-Mesia L Martínez-Díaz R González-Coloma A 《Zeitschrift für Naturforschung. C, Journal of biosciences》2011,66(5-6):225-234
Five oxindole alkaloids, three plumerane-type alkaloids, subtype haplophitine, and one aspidospermatane-type alkaloid, subtype tubotaiwine, were isolated from the medicinal plants Aspidosperma rigidum and A. schultesii. One compound was identified as the transoid conformer of 18-oxo-O-methylaspidoalbine which was not previously described. The antiparasitic activity of all compounds against Trypanosoma cruzi and Leishmania infantum and their non-specific cytotoxicity against mammalian cells were also determined. 相似文献
923.
Pedro Ortega-Mart��nez Beatriz ��gueda Luz Marina Fern��ndez-Toir��n Fernando Mart��nez-Pe?a 《Mycorrhiza》2011,21(1):65-70
The study of factors influencing the production and development of wild edible mushroom sporocarps is extremely important
in the characterization of the fungi life cycle. The main objective of this work is to determine how tree age influences the
speed of sporocarp growth of edible ectomycorrhizal fungi Boletus edulis and Lactarius deliciosus in a Pinus sylvestris stand. This study is based on information recorded on a weekly basis every autumn between 1995 and 2008 in a set of permanent
plots in Spain. Sporocarps are collected weekly, and as a result, specimens may not have reached their maximum size. The study
area is a monospecific P. sylvestris stand. Three age classes were considered: under 30 years, between 31 and 70 years, and over 70 years. Sporocarps of B. edulis and L. deliciosus grow faster in the first age class stands than in the other two, and in the second age class stands, sporocarps are more
than 50% smaller. The average weight of the picked B. edulis sporocarps clearly varies in the three age classes considered, with its maximum in the first age class (127 g and 6.8 cm
cap diameter), minimum in the second age class (68 g and 4.7 cm cap diameter), and showing a relative maximum in the third
(79 g and 4.3 cm cap diameter). L. deliciosus sporocarps are on average larger in the first age class (48 g and 7.4 cm cap diameter), decreasing in the second (20 g and
5.8 cm cap diameter) and also in the third (21 g and 5.3 cm cap diameter). The results show the influence of tree age in speed
of sporocarp growth for the two ectomycorrhizal species. 相似文献
924.
Roy Mackenzie Javier A. Barros Miguel A. Martínez 《World journal of microbiology & biotechnology》2011,27(11):2499-2504
Aerobic heterotrophic bacteria present in the surface water of three cold and nutrient-poor lakes in the Chilean Patagonia
(Alto Reino, Las Dos Torres and Venus) were analysed for genetic similarity and metabolic diversity using 16S ribosomal DNA
and the Biolog EcoPlateTM system, respectively. Bacterial fingerprints of water samples in enriched and non-enriched nutrient broth demonstrated a
>50% fingerprinting similarity between the lakes. Metabolic activity was also similar. However, the Biolog EcoPlateTM system carbon substrates revealed functional diversity. Lake Las Dos Torres showed the most fingerprinting similarity between
enriched and non-enriched cold water samples. The amounts of living and viable bacteria were also higher in this lake’s water
sample, suggesting a predominance of facultative oligotrophic groups. DNA sequencing analysis demonstrated the presence of
phylum Bacteroidetes in Lake Alto Reino; phyla Bacteroidetes and Gammaproteobacteria in Lake Las Dos Torres; and phyla Bacteroidetes,
Alphaproteobacteria, and Gammaproteobacteria in Lake Venus. Although each lake had a unique bacterial community structure,
the different bacterial groups may be performing similar metabolic functions, given the similarity in extreme environmental
conditions. 相似文献
925.
Taboada-Puig Roberto Lú-Chau Thelmo Moreira María Teresa Feijoo Gumersindo Martínez María Jesús Lema Juan Manuel 《World journal of microbiology & biotechnology》2011,27(7):1735-1735
World Journal of Microbiology and Biotechnology - 相似文献
926.
Natalie Barnes Roger N. Bamber Graham Bennell Nils Cornelius David Glassom Sophie Conroy-Dalton Henderson Narriman Jiddawi Christine N. W. Lee Adriano Macia Daudi J. Msangameno Jos�� Paula Saleh Yahya Timothy J. Ferrero 《Biodiversity and Conservation》2011,20(10):2075-2109
The transboundary networks of Marine Protected Areas (MPAs) project, TRANSMAP, assessed local turnover and regional biodiversity across the East African Marine Ecoregion, where inter-governmental co-operation has been working to connect local MPAs. The benthic fauna in the three most dominant habitats on this coastline??beaches, mangroves and seagrasses??were studied in two Regions (Northern Region, 10?C13°S; Southern Region, 25?C28°S). Meiofaunal taxa were used as the model faunal group owing to their diversity and abundance across habitat types and environmental conditions. Meiofaunal abundance averaged 2,500 individuals 10 cm?2 and was generally higher in mangrove and seagrass sediments than on the beaches, and was significantly different between habitats × Regions. In total, 18 taxa were recorded with highest diversity in the beach samples. Diversity indices and assemblage structure were significantly different between habitats, but also Regions. Specific granulometric 1?? size classes, shore-height and number of rain days were the factors most significantly correlating with the observed assemblage patterns. Additionally, the size of a MPA and latitude (which correlated with MPA age, but not number of rain days), were the factors fitting best with meiofaunal assemblage patterns across the beaches, the habitat for which the most comprehensive data were generated. Sample diversity was higher in the Southern Region, and although within- and across-habitats diversity were similar across the Regions, the two Regions appeared to provide complementary habitats and supported different assemblages. Within the Regions, beaches (the only habitat for which more than one location was sampled) were significantly different between Locations, supporting the establishment of multiple protected locations of the same habitat within each transboundary MPA. 相似文献
927.
Marquès-Bueno MM Moreno-Romero J Abas L De Michele R Martínez MC 《The Plant journal : for cell and molecular biology》2011,67(1):169-180
Protein kinase CK2 is a pleiotropic Ser/Thr kinase, evolutionary conserved in eukaryotes. Studies performed in different organisms, from yeast to humans, have highlighted the importance of CK2 in cell growth and cell-cycle control. However, the signalling pathways in which CK2 is involved have not been fully identified. In plants, the phytohormone auxin is a major regulator of cell growth. Recent discoveries have demonstrated that differential distribution of within auxin plant tissues is essential for developmental processes, and that this distribution is dependent on polar auxin transport. We report here that a dominant-negative mutant of CK2 (CK2mut) in Arabidopsis thaliana shows phenotypic traits that are typically linked to alterations in auxin-dependent processes. However, CK2mut plants exhibit normal responses to exogenous indole-3-acetic acid (IAA) indicating that they are not affected in the perception of the hormone but upstream in the pathway. We demonstrate that mutant plants are not deficient in IAA but are impaired in its transport. Using genetic and pharmacological tools we show that CK2 activity depletion hinders correct formation of auxin gradients and leads to widespread changes in the expression of auxin-related genes. In particular, members of the auxin efflux carrier family (PINs), and the protein kinase PINOID, both key regulators of auxin fluxes, were misexpressed. PIN4 and PIN7 were also found mislocalized, with accumulation in endosomal bodies. We propose that CK2 functions in the regulation of auxin-signalling pathways, particularly in auxin transport. 相似文献
928.
929.
The aim of this work was to obtain biodiesel from animal fats, an inedible feedstock. Three different types of fats were used to produce biodiesel; their main characteristic was high free fatty acid content. Animal fats were transesterified with acid catalyst and basic catalyst with and without pre-esterification. Biodiesel of 89.0 wt.% ester content was obtained by acid-transesterification (9 wt.% H2SO4, 6:1 methanol:fats molar ratio, 60 °C, 48 h). Pre-esterification conditions were studied for different fats and acid catalysts: 0.5 wt.% H2SO4 or 1.0 wt.% p-TsOH, 6:1 methanol:fats molar ratio, 65 °C and 4 h made it possible to obtain fats with acid value less than 0.5% FFA. Pre-treatment was effective for fats with different FFA content. Alkali transesterification of esterified fats resulted in a product with 97.3 wt.% ester content. Biodiesel quality was evaluated and most of properties were well within EN 14214. 相似文献
930.
Anders Nielsen Ingolf Steffan-Dewenter Catrin Westphal Olivia Messinger Simon G. Potts Stuart P. M. Roberts Josef Settele Hajnalka Szentgy?rgyi Bernard E. Vaissi��re Michalis Vaitis Michal Woyciechowski Ioannis Bazos Jacobus C. Biesmeijer Riccardo Bommarco William E. Kunin Thomas Tscheulin Ellen Lamborn Theodora Petanidou 《Ecological Research》2011,26(5):969-983
The decline of bees has raised concerns regarding their conservation and the maintenance of ecosystem services they provide to bee-pollinated wild flowers and crops. Although the Mediterranean region is a hotspot for bee species richness, their status remains poorly studied. There is an urgent need for cost-effective, reliable, and unbiased sampling methods that give good bee species richness estimates. This study aims: (a) to assess bee species richness in two common Mediterranean habitat types: semi-natural scrub (phrygana) and managed olive groves; (b) to compare species richness in those systems to that of other biogeographic regions, and (c) to assess whether six different sampling methods (pan traps, variable and standardized transect walks, observation plots and trap nests), previously tested in other European biogeographic regions, are suitable in Mediterranean communities. Eight study sites, four per habitat type, were selected on the island of Lesvos, Greece. The species richness observed was high compared to other habitat types worldwide for which comparable data exist. Pan traps collected the highest proportion of the total bee species richness across all methods at the scale of a study site. Variable and standardized transect walks detected the highest total richness over all eight study sites. Trap nests and observation plots detected only a limited fraction of the bee species richness. To assess the total bee species richness in bee diversity hotspots, such as the studied habitats, we suggest a combination of transect walks conducted by trained bee collectors and pan trap sampling. 相似文献