Authors: <div class="autor_fcen" id="8534">Thomas, M.G.</div>; <div class="autor_fcen" id="5196">Luchelli, L.</div>; Pascual, M.; Gottifredi, V.; <div class="autor_fcen" id="982">Boccaccio, G.L.</div>
Publication Date: 2012.
The p53 tumor suppressor protein is an important regulator of cell proliferation and apoptosis. p53 can be found in the nucleus and in the cytosol, and the subcellular location is key to control p53 function. In this work, we found that a widely used monoclonal antibody against p53, termed Pab 1801 (Pan antibody 1801) yields a remarkable punctate signal in the cytoplasm of several cell lines of human origin. Surprisingly, these puncta were also observed in two independent p53-null cell lines. Moreover, the foci stained with the Pab 1801 were present in rat cells, although Pab 1801 recognizes an epitope that is not conserved in rodent p53. In contrast, the Pab 1801 nuclear staining corresponded to genuine p53, as it was upregulated by p53-stimulating drugs and absent in p53-null cells. We identified the Pab 1801 cytoplasmic puncta as P Bodies (PBs), which are involved in mRNA regulation. We found that, in several cell lines, including U2OS, WI38, SK-N-SH and HCT116, the Pab 1801 puncta strictly colocalize with PBs identified with specific antibodies against the PB components Hedls, Dcp1a, Xrn1 or Rck/p54. PBs are highly dynamic and accordingly, the Pab 1801 puncta vanished when PBs dissolved upon treatment with cycloheximide, a drug that causes polysome stabilization and PB disruption. In addition, the knockdown of specific PB components that affect PB integrity simultaneously caused PB dissolution and the disappearance of the Pab 1801 puncta. Our results reveal a strong cross-reactivity of the Pab 1801 with unknown PB component(s). This was observed upon distinct immunostaining protocols, thus meaning a major limitation on the use of this antibody for p53 imaging in the cytoplasm of most cell types of human or rodent origin. © 2012 Thomas et al.
Author affiliation: Thomas, M.G. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.
Author affiliation: Luchelli, L. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.
Author affiliation: Boccaccio, G.L. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.
Keywords: cell marker; cycloheximide; decapping enzyme 1a; decapping enzyme 1b; decapping enzyme 2; epitope; exoribonuclease; exoribonuclease 1; messenger RNA; monoclonal antibody; pantropic antibody 1801; protein 4ET; protein Hedls; protein p53; protein p54; small interfering RNA; unclassified drug; epitope; protein p53; TP53 protein, human; animal cell; animal tissue; article; cell component; cell disruption; cell line; cell stimulation; cell strain HCT116; cellular distribution; concentration (parameters); controlled study; cross reaction; dissolution; Drosophila; embryo; fetus; gene control; gene silencing; genetic transfection; human; human cell; image analysis; immunohistochemistry; intracellular signaling; nonhuman; polysome; processing body; protein analysis; protein localization; rat; upregulation; animal; antibody specificity; chemistry; cytoplasm; immunology; metabolism; Sprague Dawley rat; tumor cell line; Rattus; Rodentia; Animals; Antibodies, Monoclonal, Murine-Derived; Antibody Specificity; Cell Line, Tumor; Cytoplasm; Epitopes; Humans; Immunohistochemistry; Rats; Rats, Sprague-Dawley; Tumor Suppressor Protein p53.
Repository: Biblioteca Digital (UBA-FCEN). Universidad Nacional de Buenos Aires. Facultad de Ciencias Exactas y Naturales
Authors: <div class="autor_fcen" id="3432">Galli, S.</div>; Jahn, O.; Hitt, R.; Hesse, D.; Opitz, L.; Plessmann, U.; Urlaub, H.; Poderoso, J.J.; <div class="autor_fcen" id="4466">Jares-Erijman, E.A.</div>; Jovin, T.M.
Publication Date: 2009.
Extracellular signal-regulated protein kinase 1 and 2 (ERK1/2) are members of the MAPK family and participate in the transduction of stimuli in cellular responses. Their long-term actions are accomplished by promoting the expression of specific genes whereas faster responses are achieved by direct phosphorylation of downstream effectors located throughout the cell. In this study we determined that hERK1 translocates to the mitochondria of HeLa cells upon a proliferative stimulus. In the mitochondrial environment, hERK1 physically associates with (i) at least 5 mitochondrial proteins with functions related to transport (i.e. VDAC1), signalling, and metabolism; (ii) histones H2A and H4; and (iii) other cytosolic proteins. This work indicates for the first time the presence of diverse ERK-complexes in mitochondria and thus provides a new perspective for assessing the functions of ERK1 in the regulation of cellular signalling and trafficking in HeLa cells. © 2009 Galli et al.
Author affiliation: Galli, S. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.
Author affiliation: Jares-Erijman, E.A. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.
Keywords: histone H2A; histone H4; mitogen activated protein kinase 1; mitogen activated protein kinase 3; voltage dependent anion channel; glutathione transferase; article; complex formation; controlled study; enzyme activity; gene control; gene expression; gene location; HeLa cell; human; human cell; mitochondrion; nucleotide sequence; protein protein interaction; protein transport; signal transduction; amino acid sequence; cell proliferation; gene expression profiling; gene expression regulation; mass spectrometry; metabolism; methodology; molecular genetics; proteomics; sequence homology; Amino Acid Sequence; Cell Proliferation; Gene Expression Profiling; Gene Expression Regulation, Enzymologic; Gene Expression Regulation, Neoplastic; Glutathione Transferase; Hela Cells; Humans; MAP Kinase Signaling System; Mitochondria; Mitogen-Activated Protein Kinase 3; Molecular Sequence Data; Proteomics; Sequence Homology, Amino Acid; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization.
Repository: Biblioteca Digital (UBA-FCEN). Universidad Nacional de Buenos Aires. Facultad de Ciencias Exactas y Naturales
Publication Date: 2012.
Lipid-protein interactions play an essential role in the regulation of biological function of integral membrane proteins; however, the underlying molecular mechanisms are not fully understood. Here we explore the modulation by phospholipids of the enzymatic activity of the plasma membrane calcium pump reconstituted in detergent-phospholipid mixed micelles of variable composition. The presence of increasing quantities of phospholipids in the micelles produced a cooperative increase in the ATPase activity of the enzyme. This activation effect was reversible and depended on the phospholipid/detergent ratio and not on the total lipid concentration. Enzyme activation was accompanied by a small structural change at the transmembrane domain reported by 1-aniline-8-naphtalenesulfonate fluorescence. In addition, the composition of the amphipilic environment sensed by the protein was evaluated by measuring the relative affinity of the assayed phospholipid for the transmembrane surface of the protein. The obtained results allow us to postulate a two-stage mechanistic model explaining the modulation of protein activity based on the exchange among non-structural amphiphiles at the hydrophobic transmembrane surface, and a lipid-induced conformational change. The model allowed to obtain a cooperativity coefficient reporting on the efficiency of the transduction step between lipid adsorption and catalytic site activation. This model can be easily applied to other phospholipid/detergent mixtures as well to other membrane proteins. The systematic quantitative evaluation of these systems could contribute to gain insight into the structure-activity relationships between proteins and lipids in biological membranes. © 2012 Dodes Traian et al.
Author affiliation: Levi, V. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.
Keywords: 8 anilino 1 naphthalenesulfonic acid; adenosine triphosphatase (calcium); amphophile; membrane protein; phospholipid; adsorption kinetics; article; binding affinity; conformational transition; controlled study; enzyme activation; enzyme active site; enzyme activity; enzyme structure; fluorescence spectroscopy; human; human cell; hydrophobicity; micelle; molecular mechanics; molecular model; protein domain; protein lipid interaction; signal transduction; Algorithms; Enzyme Activation; Humans; Membrane Proteins; Micelles; Models, Molecular; Phospholipids; Plasma Membrane Calcium-Transporting ATPases.
Authors: Boccia, M.; <div class="autor_fcen" id="3324">Freudenthal, R.</div>; Blake, M.; <div class="autor_fcen" id="2338">De La Fuente, V.</div>; Acosta, G.; Baratti, C.; <div class="autor_fcen" id="7439">Romano, A.</div>
Publication Date: 2007.
Initially, memory is labile and requires consolidation to become stable. However, several studies support that consolidated memories can undergo a new period of lability after retrieval. The mechanistic differences of this process, termed reconsolidation, with the consolidation process are under debate, including the participation of hippocampus. Up to this point, few reports describe molecular changes and, in particular, transcription factor (TF) involvement in memory restabilization. Increasing evidence supports the participation of the TF nuclear factor-κB (NF-κB) in memory consolidation. Here, we demonstrate that the inhibition of NF-κB after memory reactivation impairs retention of a hippocampal-dependent inhibitory avoidance task in mice. We used two independent disruptive strategies to reach this conclusion. First, we administered intracerebroventricular or intrahippocampal sulfasalazine, an inhibitor of IKK (IκB kinase), the kinase that activates NF-κB. Second, we infused intracerebroventricular or intrahippocampal κB decoy, a direct inhibitor of NF-κB consisting of a double-stranded DNA oligonucleotide that contains the κB consensus sequence. When injected immediately after memory retrieval, sulfasalazine or κB decoy (Decoy) impaired long-term retention. In contrast, a one base mutated κB decoy (mDecoy) had no effect. Furthermore, we also found NF-κB activation in the hippocampus, with a peak 15 min after memory retrieval. This activation was earlier than that found during consolidation. Together, these results indicate that NF-κB is an important transcriptional regulator in memory consolidation and reconsolidation in hippocampus, although the temporal kinetics of activation differs between the two processes. Copyright © 2007 Society for Neuroscience.
Author affiliation: Freudenthal, R. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.
Author affiliation: De La Fuente, V. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.
Author affiliation: Romano, A. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.
Keywords: κB decoy; Hippocampus; Inhibitory avoidance; NF-κB; Reconsolidation; Sulfasalazine; double stranded DNA; immunoglobulin enhancer binding protein; salazosulfapyridine; animal experiment; article; avoidance behavior; brain function; controlled study; hippocampus; information processing; male; memory; memory consolidation; mouse; nonhuman; priority journal; task performance; Animals; Hippocampus; Injections, Intraventricular; Male; Memory; Mice; NF-kappa B; Sulfasalazine.
Authors: Perez Lloret, Santiago
Publication Date: 2013.
Phase IIa randomized double-blind, placebo-controlled study of inhaled apomorphine as acute challenge for rescuing 'off' periods in patients with established Parkinson's disease
Author affiliation: Perez Lloret, Santiago. Universite de Toulose - Le Mirail; Francia. Pontificia Universidad Católica Argentina "Santa María de los Buenos Aires"; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina
Repository: CONICET Digital (CONICET). Consejo Nacional de Investigaciones Científicas y Técnicas
Publication Date: 2009.
Background: Cognitive experiences during the early stages of life play an important role in shaping the future behavior in mammals but also in insects, in which precocious learning can directly modify behaviors later in life depending on both the timing and the rearing environment. However, whether olfactory associative learning acquired early in the adult stage of insects affect memorizing of new learning events has not been studied yet. Methodology: Groups of adult honeybee workers that experienced an odor paired with a sucrose solution 5 to 8 days or 9 to 12 days after emergence were previously exposed to (i) a rewarded experience through the offering of scented food, or (ii) a non-rewarded experience with a pure volatile compound in the rearing environment. Principal Findings: Early rewarded experiences (either at 1-4 or 5-8 days of adult age) enhanced retention performance in 9-12-day-conditioned bees when they were tested at 17 days of age. The highest retention levels at this age, which could not be improved with prior rewarded experiences, were found for memories established at 5-8 days of adult age. Associative memories acquired at 9-12 days of age showed a weak effect on retention for some pure pre-exposed volatile compounds; whereas the sole exposure of an odor at any younger age did not promote long-term effects on learning performance. Conclusions: The associative learning events that occurred a few days after adult emergence improved memorizing in middle-aged bees. In addition, both the timing and the nature of early sensory inputs interact to enhance retention of new learning events acquired later in life, an important matter in the social life of honeybees. © 2009 Arenas et al.
Author affiliation: Arenas, A. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.
Author affiliation: Fernández, V.M. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.
Author affiliation: Farina, W.M. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.
Keywords: sucrose; volatile agent; carbohydrate; animal behavior; article; behavioral science; controlled study; honeybee; memory consolidation; nonhuman; reward; sensory stimulation; social behavior; state dependent learning; task performance; aging; animal; bee; conditioning; drug effect; environment; feeding behavior; learning; long term memory; longevity; odor; physiology; smelling; solution and solubility; volatilization; Apis mellifera; Apoidea; Hexapoda; Mammalia; Aging; Animals; Association Learning; Bees; Behavior, Animal; Carbohydrates; Conditioning (Psychology); Environment; Feeding Behavior; Longevity; Odors; Olfactory Perception; Retention (Psychology); Solutions; Volatilization.
Authors: Escobar, M.J.; Rivera-Rei, A.; Decety, J.; Huepe, D.; Cardona, J.F.; Canales-Johnson, A.; <div class="autor_fcen" id="8097">Sigman, M.</div>; Mikulan, E.; Helgiu, E.; Baez, S.; Manes, F.; Lopez, V.; Ibañez, A.
Publication Date: 2013.
Background: Research suggests that individuals with different attachment patterns process social information differently, especially in terms of facial emotion recognition. However, few studies have explored social information processes in adolescents. This study examined the behavioral and ERP correlates of emotional processing in adolescents with different attachment orientations (insecure attachment group and secure attachment group; IAG and SAG, respectively). This study also explored the association of these correlates to individual neuropsychological profiles. Methodology/Principal Findings: We used a modified version of the dual valence task (DVT), in which participants classify stimuli (faces and words) according to emotional valence (positive or negative). Results showed that the IAG performed significantly worse than SAG on tests of executive function (EF attention, processing speed, visuospatial abilities and cognitive flexibility). In the behavioral DVT, the IAG presented lower performance and accuracy. The IAG also exhibited slower RTs for stimuli with negative valence. Compared to the SAG, the IAG showed a negative bias for faces; a larger P1 and attenuated N170 component over the right hemisphere was observed. A negative bias was also observed in the IAG for word stimuli, which was demonstrated by comparing the N170 amplitude of the IAG with the valence of the SAG. Finally, the amplitude of the N170 elicited by the facial stimuli correlated with EF in both groups (and negative valence with EF in the IAG). Conclusions/Significance: Our results suggest that individuals with different attachment patterns process key emotional information and corresponding EF differently. This is evidenced by an early modulation of ERP components' amplitudes, which are correlated with behavioral and neuropsychological effects. In brief, attachments patterns appear to impact multiple domains, such as emotional processing and EFs. © 2013 Escobar et al.
Author affiliation: Sigman, M. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.
Authors: <div class="autor_fcen" id="3162">Figuerola, E.L.M.</div>; <div class="autor_fcen" id="4086">Guerrero, L.D.</div>; <div class="autor_fcen" id="7476">Rosa, S.M.</div>; Simonetti, L.; Duval, M.E.; Galantini, J.A.; Bedano, J.C.; Wall, L.G.; <div class="autor_fcen" id="2804">Erijman, L.</div>
Publication Date: 2012.
The rise in the world demand for food poses a challenge to our ability to sustain soil fertility and sustainability. The increasing use of no-till agriculture, adopted in many areas of the world as an alternative to conventional farming, may contribute to reduce the erosion of soils and the increase in the soil carbon pool. However, the advantages of no-till agriculture are jeopardized when its use is linked to the expansion of crop monoculture. The aim of this study was to survey bacterial communities to find indicators of soil quality related to contrasting agriculture management in soils under no-till farming. Four sites in production agriculture, with different soil properties, situated across a west-east transect in the most productive region in the Argentinean pampas, were taken as the basis for replication. Working definitions of Good no-till Agricultural Practices (GAP) and Poor no-till Agricultural Practices (PAP) were adopted for two distinct scenarios in terms of crop rotation, fertilization, agrochemicals use and pest control. Non-cultivated soils nearby the agricultural sites were taken as additional control treatments. Tag-encoded pyrosequencing was used to deeply sample the 16S rRNA gene from bacteria residing in soils corresponding to the three treatments at the four locations. Although bacterial communities as a whole appeared to be structured chiefly by a marked biogeographic provincialism, the distribution of a few taxa was shaped as well by environmental conditions related to agricultural management practices. A statistically supported approach was used to define candidates for management-indicator organisms, subsequently validated using quantitative PCR. We suggest that the ratio between the normalized abundance of a selected group of bacteria within the GP1 group of the phylum Acidobacteria and the genus Rubellimicrobium of the Alphaproteobacteria may serve as a potential management-indicator to discriminate between sustainable vs. non-sustainable agricultural practices in the Pampa region. © 2012 Figuerola et al.
Author affiliation: Figuerola, E.L.M. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.
Author affiliation: Guerrero, L.D. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.
Author affiliation: Rosa, S.M. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.
Author affiliation: Erijman, L. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.
Keywords: carbon; nitrogen; Acidobacteria; agricultural procedures; article; bacterium; climate; community structure; controlled study; crop rotation; fertilization; geographic distribution; microbial community; no till crop production; nonhuman; pest control; pH; physical chemistry; pyrosequencing; quantitative analysis; real time polymerase chain reaction; Rubellimicrobium; seasonal variation; sequence analysis; soil analysis; soil microflora; soil moisture; soil quality; soil texture; validation process; Agriculture; Argentina; Bacteria; Crops, Agricultural; Geography; Phylogeny; Soil; Soil Microbiology; Acidobacteria; Alphaproteobacteria; Bacteria (microorganisms).
Authors: Giordano, D.; Boron, I.; Abbruzzetti, S.; van Leuven, W.; Nicoletti, F.P.; Forti, F.; Bruno, S.; Cheng, C.-H.C.; Moens, L.; di Prisco, G.; <div class="autor_fcen" id="6058">Nadra, A.D.</div>; <div class="autor_fcen" id="2857">Estrin, D.</div>; Smulevich, G.; Dewilde, S.; Viappiani, C.; Verde, C.
Publication Date: 2012.
The Antarctic icefish Chaenocephalus aceratus lacks the globins common to most vertebrates, hemoglobin and myoglobin, but has retained neuroglobin in the brain. This conserved globin has been cloned, over-expressed and purified. To highlight similarities and differences, the structural features of the neuroglobin of this colourless-blooded fish were compared with those of the well characterised human neuroglobin as well as with the neuroglobin from the retina of the red blooded, hemoglobin and myoglobin-containing, closely related Antarctic notothenioid Dissostichus mawsoni. A detailed structural and functional analysis of the two Antarctic fish neuroglobins was carried out by UV-visible and Resonance Raman spectroscopies, molecular dynamics simulations and laser-flash photolysis. Similar to the human protein, Antarctic fish neuroglobins can reversibly bind oxygen and CO in the Fe2+ form, and show six-coordination by distal His in the absence of exogenous ligands. A very large and structured internal cavity, with discrete docking sites, was identified in the modelled three-dimensional structures of the Antarctic neuroglobins. Estimate of the free-energy barriers from laser-flash photolysis and Implicit Ligand Sampling showed that the cavities are accessible from the solvent in both proteins. Comparison of structural and functional properties suggests that the two Antarctic fish neuroglobins most likely preserved and possibly improved the function recently proposed for human neuroglobin in ligand multichemistry. Despite subtle differences, the adaptation of Antarctic fish neuroglobins does not seem to parallel the dramatic adaptation of the oxygen carrying globins, hemoglobin and myoglobin, in the same organisms. © 2012 Giordano et al.
Author affiliation: Nadra, A.D. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.
Author affiliation: Estrin, D. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.
Keywords: hemoglobin; myoglobin; neuroglobin; article; autooxidation; biophysics; Chaenocephalus aceratus; controlled study; Dissostichus mawsoni; fish; human; human versus animal comparison; laser flash photolysis; molecular cloning; molecular dynamics; nonhuman; oxygen affinity; oxygen transport; photolysis; protein analysis; protein expression; protein function; protein purification; protein structure; Raman spectrometry; site directed mutagenesis; ultraviolet spectroscopy; Animals; Biophysics; Carbon Monoxide; Fishes; Gene Knockout Techniques; Globins; Hemoglobins; Humans; Kinetics; Ligands; Molecular Dynamics Simulation; Mutagenesis, Site-Directed; Nerve Tissue Proteins; Spectrophotometry, Ultraviolet; Spectrum Analysis, Raman; Chaenocephalus aceratus; Dissostichus mawsoni; Vertebrata.
Publication Date: 2011.
Experiments with insects and crabs have demonstrated their remarkable capacity to learn and memorize complex visual features (Giurfa et al., 2001; Pedreira and Maldonado, 2003; Chittka and Niven, 2009). Such abilities are thought to require modular brain processing similar to that occurring in vertebrates (Menzel and Giurfa, 2001). Yet, physiological evidence for this type of functioning in the small brains of arthropods is still scarce (Liu et al., 1999, 2006; Menzel and Giurfa, 2001). In the crab Chasmagnathus granulatus, the learning rate as well as the long-term memory of a visual stimulus has been found to be reflected in the performance of identified lobula giant neurons (LGs) (Tomsic et al., 2003). The memory can only be evoked in the training context, indicating that animals store two components of the learned experience, one related to the visual stimulus and one related to the visual context (Tomsic et al., 1998; Hermitte et al., 1999). By performing intracellular recordings in the intact animal, we show that the ability of crabs to generalize the learned stimulus into new space positions and to distinguish it from a similar but unlearned stimulus, two of the main attributes of stimulus memory, is reflected by the performance of the LGs. Conversely, we found that LGs do not support the visual context memory component. Our results provide physiological evidence that the memory traces regarding "what" and "where" are stored separately in the arthropod brain. © 2011 the authors.
Author affiliation: Sztarker, J. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.
Author affiliation: Tomsic, D. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.
Keywords: animal behavior; animal experiment; article; brain function; controlled study; crab; learning; long term memory; male; memory consolidation; nerve cell network; neuromodulation; neurotransmission; nonhuman; priority journal; stimulus response; task performance; visual stimulation; Action Potentials; Animals; Brachyura; Generalization, Stimulus; Learning; Male; Memory; Neurons; Photic Stimulation.