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991.
G. Martins I. Henriques D. C. Ribeiro A. Correia P. L. E. Bodelier J. V. Cruz 《Geomicrobiology journal》2013,30(8):704-715
In the Azores, the advanced trophic state of the lakes requires a fast intervention to achieve the good ecological status prescribed by the Water Framework Directive. Despite the considerable effort made to describe the phytoplankton growing on the water column, the lack of information regarding the microbial processes in sediments is still high. Thus, for the successful implementation of internal management actions, the present work explored the relationships between geochemical profiles and dominant members of the bacterial community in sediments from eutrophic Azorean lakes. Lake Azul geochemical profiles were quite homogeneous for all parameters, while in lake Furnas the total iron profile presented a peak below the aerobic layer. For lake Verde, the concentrations of all studied parameters (20 ± 2% loss-on-ignition; 2.10 ± 0.08 mg g?1 total phosphorus; 1.31 ± 0.50 mg g?1 total nitrogen; 8.06 ± 0.13 mg g?1 total iron) in the uppermost sediment layer were approximately two times higher than the ones in sediments from other lakes, decreasing with sediment depth. The higher amounts of phosphorus and organic matter in lake Verde suggested a higher internal contribution of phosphorus to eutrophication. The dominant members of the sediment bacterial community, investigated by denaturing gradient gel electrophoresis, were mostly affiliated to Proteobacteria phylum (Alpha-, Delta-, and Gamma-subclasses), group Bacteroidetes/Chlorobi and phylum Chloroflexi. The Cyanobacteria phylum was solely detected in sediments from lake Verde and lake Furnas that presented the highest amounts of nitrogen and phosphorus both in the water column and sediments, while the other phyla were detected in sediments from the three studied lakes. In conclusion, management measurers to achieve the good ecological status until 2015 should be distinct for the different lakes taking into account the relative magnitude of the nutrient sources and the bacterial diversity in sediments. 相似文献
992.
Luis A. Flores-López Margarita Díaz-Flores Rebeca García-Macedo Alejandro Ávalos-Rodríguez Marcela Vergara-Onofre Miguel Cruz Alejandra Contreras-Ramos Mina Konigsberg Clara Ortega-Camarillo 《Molecular biology reports》2013,40(8):4947-4958
Pancreatic β-cell death in type 2 diabetes has been related to p53 subcellular localisation and phosphorylation. However, the mechanisms by which p53 is phosphorylated and its activation in response to oxidative stress remain poorly understood. Therefore, the aim of this study was to investigate mitochondrial p53 phosphorylation, its subcellular localisation and its relationship with apoptotic induction in RINm5F cells cultured under high glucose conditions. Our results show that p53 phosphorylation in the mitochondrial fraction was greater at ser392 than at ser15. This increased phosphorylation correlated with an increase in reactive oxygen species, a decrease in the Bcl-2/Bax ratio, a release of cytochrome c and an increase in the rate of apoptosis. We also observed a decline in ERK 1/2 phosphorylation over time, which is an indicator of cell proliferation. To identify the kinase responsible for phosphorylating p53, p38 mitogen-activated protein kinase (MAPK) activation was analysed. We found that high glucose induced an increase in p38 MAPK phosphorylation in the mitochondria after 24–72 h. Moreover, the phosphorylation of p53 (ser392) by p38 MAPK in mitochondria was confirmed by colocalisation studies with confocal microscopy. The addition of a specific p38 MAPK inhibitor (SB203580) to the culture medium during high glucose treatment blocked p53 mobilisation to the mitochondria and phosphorylation; thus, the release of cytochrome c and the apoptosis rate in RINm5F cells decreased. These results suggest that mitochondrial p53 phosphorylation by p38 MAPK plays an important role in RINm5F cell death under high glucose conditions. 相似文献
993.
Michael Gamalinda Jelena Jakovljevic Reyes Babiano Jason Talkish Jesús de la Cruz John L. Woolford Jr 《Nucleic acids research》2013,41(3):1965-1983
Ribosome synthesis involves the coordinated folding and processing of pre-rRNAs with assembly of ribosomal proteins. In eukaryotes, these events are facilitated by trans-acting factors that propel ribosome maturation from the nucleolus to the cytoplasm. However, there is a gap in understanding how ribosomal proteins configure pre-ribosomes in vivo to enable processing to occur. Here, we have examined the role of adjacent yeast r-proteins L17, L35 and L37 in folding and processing of pre-rRNAs, and binding of other proteins within assembling ribosomes. These three essential ribosomal proteins, which surround the polypeptide exit tunnel, are required for 60S subunit formation as a consequence of their role in removal of the ITS2 spacer from 27SB pre-rRNA. L17-, L35- and L37-depleted cells exhibit turnover of aberrant pre-60S assembly intermediates. Although the structure of ITS2 does not appear to be grossly affected in their absence, these three ribosomal proteins are necessary for efficient recruitment of factors required for 27SB pre-rRNA processing, namely, Nsa2 and Nog2, which associate with pre-60S ribosomal particles containing 27SB pre-rRNAs. Altogether, these data support that L17, L35 and L37 are specifically required for a recruiting step immediately preceding removal of ITS2. 相似文献
994.
Maria Aurineide Rodrigues Alejandra Matiz Aline Bertinatto Cruz Aline Tiemi Matsumura Cassia Ayumi Takahashi Leonardo Hamachi Lucas Macedo Félix Paula Natália Pereira Sabrina Ribeiro Latansio-Aidar Marcos Pereira Marinho Aidar Diego Demarco Luciano Freschi Helenice Mercier Gilberto Barbante Kerbauy 《Annals of botany》2013,112(1):17-29
Background and Aims
A positive correlation between tissue thickness and crassulacean acid metabolism (CAM) expression has been frequently suggested. Therefore, this study addressed the question of whether water availability modulates photosynthetic plasticity in different organs of two epiphytic orchids with distinct leaf thickness.Methods
Tissue morphology and photosynthetic mode (C3 and/or CAM) were examined in leaves, pseudobulbs and roots of a thick-leaved (Cattleya walkeriana) and a thin-leaved (Oncidium ‘Aloha’) epiphytic orchid. Morphological features were studied comparing the drought-induced physiological responses observed in each organ after 30 d of either drought or well-watered treatments.Key Results
Cattleya walkeriana, which is considered a constitutive CAM orchid, displayed a clear drought-induced up-regulation of CAM in its thick leaves but not in its non-leaf organs (pseudobulbs and roots). The set of morphological traits of Cattleya leaves suggested the drought-inducible CAM up-regulation as a possible mechanism of increasing water-use efficiency and carbon economy. Conversely, although belonging to an orchid genus classically considered as performing C3 photosynthesis, Oncidium ‘Aloha’ under drought seemed to express facultative CAM in its roots and pseudobulbs but not in its leaves, indicating that such photosynthetic responses might compensate for the lack of capacity to perform CAM in its thin leaves. Morphological features of Oncidium leaves also indicated lower efficiency in preventing water and CO2 losses, while aerenchyma ducts connecting pseudobulbs and leaves suggested a compartmentalized mechanism of nighttime carboxylation via phosphoenolpyruvate carboxylase (PEPC) (pseudobulbs) and daytime carboxylation via Rubisco (leaves) in drought-exposed Oncidium plants.Conclusions
Water availability modulated CAM expression in an organ-compartmented manner in both orchids studied. As distinct regions of the same orchid could perform different photosynthetic pathways and variable degrees of CAM expression depending on the water availability, more attention should be addressed to this in future studies concerning the abundance of CAM plants. 相似文献995.
996.
Wilton P. Cruz Renato A. Sarmento Adenir V. Teodoro Marçal P. Neto Maíra Ignacio 《Experimental & applied acarology》2013,60(4):509-519
Seasonal changes in climate and plant diversity are known to affect the population dynamics of both pests and natural enemies within agroecosystems. In Brazil, spontaneous plants are usually tolerated in small-scale physic nut plantations over the year, which in turn may mediate interactions between pests and natural enemies within this agroecosystem. Here, we aimed to access the influence of seasonal variation of abiotic (temperature, relative humidity and rainfall) and biotic (diversity of spontaneous plants, overall richness and density of mites) factors on the communities of phytophagous and predatory mites found in a physic nut plantation and its associated spontaneous plants. Mite sampling was monthly conducted in dicotyledonous and monocotyledonous leaves of spontaneous plants as well as in physic nut shrubs over an entire year. In the dry season there was a higher abundance of phytophagous mites (Tenuipalpidae, Tarsonemidae and Tetranychidae) on spontaneous plants than on physic nut shrubs, while predatory mites (Phytoseiidae) showed the opposite pattern. The overall density of mites on spontaneous plants increased with relative humidity and diversity of spontaneous plants. Rainfall was the variable that most influenced the density of mites inhabiting physic nut shrubs. Agroecosystems comprising spontaneous plants associated with crops harbour a rich mite community including species of different trophic levels which potentially benefit natural pest control due to increased diversity and abundance of natural enemies. 相似文献
997.
David Cruz‐Garcia Maria Ortega‐Bellido Margherita Scarpa Julien Villeneuve Marko Jovic Marc Porzner Tamas Balla Thomas Seufferlein Vivek Malhotra 《The EMBO journal》2013,32(12):1717-1729
The BAR (Bin/Amphiphysin/Rvs) domain proteins arfaptin1 and arfaptin2 are localized to the trans‐Golgi network (TGN) and, by virtue of their ability to sense and/or generate membrane curvature, could play an important role in the biogenesis of transport carriers. We report that arfaptins contain an amphipathic helix (AH) preceding the BAR domain, which is essential for their binding to phosphatidylinositol 4‐phosphate (PI(4)P)‐containing liposomes and the TGN of mammalian cells. The binding of arfaptin1, but not arfaptin2, to PI(4)P is regulated by protein kinase D (PKD) mediated phosphorylation at Ser100 within the AH. We also found that only arfaptin1 is required for the PKD‐dependent trafficking of chromogranin A by the regulated secretory pathway. Altogether, these findings reveal the importance of PI(4)P and PKD in the recruitment of arfaptins at the TGN and their requirement in the events leading to the biogenesis of secretory storage granules. 相似文献
998.
Chikwendu Ibebunjo Joel M. Chick Tracee Kendall John K. Eash Christine Li Yunyu Zhang Chad Vickers Zhidan Wu Brian A. Clarke Jun Shi Joseph Cruz Brigitte Fournier Sophie Brachat Sabine Gutzwiller QiCheng Ma Judit Markovits Michelle Broome Michelle Steinkrauss Elizabeth Skuba Jean-Rene Galarneau Steven P. Gygi David J. Glass 《Molecular and cellular biology》2013,33(2):194-212
Molecular mechanisms underlying sarcopenia, the age-related loss of skeletal muscle mass and function, remain unclear. To identify molecular changes that correlated best with sarcopenia and might contribute to its pathogenesis, we determined global gene expression profiles in muscles of rats aged 6, 12, 18, 21, 24, and 27 months. These rats exhibit sarcopenia beginning at 21 months. Correlation of the gene expression versus muscle mass or age changes, and functional annotation analysis identified gene signatures of sarcopenia distinct from gene signatures of aging. Specifically, mitochondrial energy metabolism (e.g., tricarboxylic acid cycle and oxidative phosphorylation) pathway genes were the most downregulated and most significantly correlated with sarcopenia. Also, perturbed were genes/pathways associated with neuromuscular junction patency (providing molecular evidence of sarcopenia-related functional denervation and neuromuscular junction remodeling), protein degradation, and inflammation. Proteomic analysis of samples at 6, 18, and 27 months confirmed the depletion of mitochondrial energy metabolism proteins and neuromuscular junction proteins. Together, these findings suggest that therapeutic approaches that simultaneously stimulate mitochondrogenesis and reduce muscle proteolysis and inflammation have potential for treating sarcopenia. 相似文献
999.
Alessandra Ciprandi Wanderson Marques da Silva Agenor Valadares Santos Adriano Monteiro de Castro Pimenta Marta Sofia Peixe Carepo Maria Paula Cruz Schneider Vasco Azevedo Artur Silva 《Current microbiology》2013,67(1):100-106
Chromobacterium violaceum is a beta-proteobacterium with high biotechnological potential, found in tropical environments. This bacterium causes opportunistic infections in both humans and animals, that can spread throughout several tissues, quickly leading to the death of the host. Genomic studies identified potential mechanisms of pathogenicity but no further studies were done to confirm the expression of these systems. In this study 36 unique protein entries were identified in databank from a two-dimensional profile of C. violaceum secreted proteins. Chromobacterium violaceum exoproteomic preliminary studies confirmed the production of proteins identified as virulence factors (such as a collagenase, flagellum proteins, metallopeptidases, and toxins), allowing us to better understand its pathogenicity mechanisms. Biotechnologically interesting proteins (such as chitinase and chitosanase) were also identified among the secreted proteins, as well as proteins involved in the transport and capture of amino acids, carbohydrates, and oxidative stress protection. Overall, the secreted proteins identified provide us important insights on pathogenicity mechanisms, biotechnological potential, and environment adaptation of C. violaceum. 相似文献
1000.
Osvaldo D. Castelán-Martínez Carlos Hoyo-Vadillo Emmanuel Sandoval-García Lucila Sandoval-Ramírez Miriam González-Ibarra Gloria Solano-Solano Rita A. Gómez-Díaz Esteban J. Parra Miguel Cruz Adán Valladares-Salgado 《Gene》2013
Allele frequency differences of functional CYP2C9 polymorphisms are responsible for some of the variation in drug response observed in human populations. The most relevant CYP2C9 functional variants are CYP2C9*2 (rs1799853) and CYP2C9*3 (rs1057910). These polymorphisms show variation in allele frequencies among different population groups. The present study aimed to analyze these polymorphisms in 947 Mexican-Mestizo from Mexico City and 483 individuals from five indigenous Mexican populations: Nahua, Teenek, Tarahumara, Purepecha and Huichol. The CYP2C9*2 allele frequencies in the Mestizo, Nahua and Teenek populations were 0.051, 0.007 and 0.005, respectively. As for CYP2C9*3, the allelic frequencies in the Mestizo, Nahua and Teenek populations were 0.04, 0.005 and 0.005, respectively. The CYP2C9*2 and CYP2C9*3 alleles were not observed in the Tarahumara, Purepecha and Huichol populations. These findings are in agreement with previous studies reporting very low allele frequencies for these polymorphisms in American Indigenous populations. 相似文献