Sleep and protein synthesis-dependent synaptic plasticity: impacts of sleep loss and stress

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Grønli, Janne; Soulé, Jonathan; Bramham, Clive R.

2014-01-01

Sleep has been ascribed a critical role in cognitive functioning. Several lines of evidence implicate sleep in the consolidation of synaptic plasticity and long-term memory. Stress disrupts sleep while impairing synaptic plasticity and cognitive performance. Here, we discuss evidence linking sleep to mechanisms of protein synthesis-dependent synaptic plasticity and synaptic scaling. We then consider how disruption of sleep by acute and chronic stress may impair these mechanisms and degrade sleep function. PMID:24478645

New learning while consolidating memory during sleep is actively blocked by a protein synthesis dependent process

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Levy, Roi; Levitan, David; Susswein, Abraham J

2016-01-01

Brief experiences while a memory is consolidated may capture the consolidation, perhaps producing a maladaptive memory, or may interrupt the consolidation. Since consolidation occurs during sleep, even fleeting experiences when animals are awakened may produce maladaptive long-term memory, or may interrupt consolidation. In a learning paradigm affecting Aplysia feeding, when animals were trained after being awakened from sleep, interactions between new experiences and consolidation were prevented by blocking long-term memory arising from the new experiences. Inhibiting protein synthesis eliminated the block and allowed even a brief, generally ineffective training to produce long-term memory. Memory formation depended on consolidative proteins already expressed before training. After effective training, long term memory required subsequent transcription and translation. Memory formation during the sleep phase was correlated with increased CREB1 transcription, but not CREB2 transcription. Increased C/EBP transcription was a correlate of both effective and ineffective training and of treatments not producing memory. DOI: http://dx.doi.org/10.7554/eLife.17769.001 PMID:27919318

New learning while consolidating memory during sleep is actively blocked by a protein synthesis dependent process.

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Levy, Roi; Levitan, David; Susswein, Abraham J

2016-12-06

Brief experiences while a memory is consolidated may capture the consolidation, perhaps producing a maladaptive memory, or may interrupt the consolidation. Since consolidation occurs during sleep, even fleeting experiences when animals are awakened may produce maladaptive long-term memory, or may interrupt consolidation. In a learning paradigm affecting Aplysia feeding, when animals were trained after being awakened from sleep, interactions between new experiences and consolidation were prevented by blocking long-term memory arising from the new experiences. Inhibiting protein synthesis eliminated the block and allowed even a brief, generally ineffective training to produce long-term memory. Memory formation depended on consolidative proteins already expressed before training. After effective training, long term memory required subsequent transcription and translation. Memory formation during the sleep phase was correlated with increased CREB1 transcription, but not CREB2 transcription. Increased C/EBP transcription was a correlate of both effective and ineffective training and of treatments not producing memory.

Nucleolar integrity is required for the maintenance of long-term synaptic plasticity.

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Kim D Allen

Full Text Available Long-term memory (LTM formation requires new protein synthesis and new gene expression. Based on our work in Aplysia, we hypothesized that the rRNA genes, stimulation-dependent targets of the enzyme Poly(ADP-ribose polymerase-1 (PARP-1, are primary effectors of the activity-dependent changes in synaptic function that maintain synaptic plasticity and memory. Using electrophysiology, immunohistochemistry, pharmacology and molecular biology techniques, we show here, for the first time, that the maintenance of forskolin-induced late-phase long-term potentiation (L-LTP in mouse hippocampal slices requires nucleolar integrity and the expression of new rRNAs. The activity-dependent upregulation of rRNA, as well as L-LTP expression, are poly(ADP-ribosylation (PAR dependent and accompanied by an increase in nuclear PARP-1 and Poly(ADP ribose molecules (pADPr after forskolin stimulation. The upregulation of PARP-1 and pADPr is regulated by Protein kinase A (PKA and extracellular signal-regulated kinase (ERK--two kinases strongly associated with long-term plasticity and learning and memory. Selective inhibition of RNA Polymerase I (Pol I, responsible for the synthesis of precursor rRNA, results in the segmentation of nucleoli, the exclusion of PARP-1 from functional nucleolar compartments and disrupted L-LTP maintenance. Taken as a whole, these results suggest that new rRNAs (28S, 18S, and 5.8S ribosomal components--hence, new ribosomes and nucleoli integrity--are required for the maintenance of long-term synaptic plasticity. This provides a mechanistic link between stimulation-dependent gene expression and the new protein synthesis known to be required for memory consolidation.

Protein Phosphatase 1-Dependent Transcriptional Programs for Long-Term Memory and Plasticity

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Graff, Johannes; Koshibu, Kyoko; Jouvenceau, Anne; Dutar, Patrick; Mansuy, Isabelle M.

2010-01-01

Gene transcription is essential for the establishment and the maintenance of long-term memory (LTM) and for long-lasting forms of synaptic plasticity. The molecular mechanisms that control gene transcription in neuronal cells are complex and recruit multiple signaling pathways in the cytoplasm and the nucleus. Protein kinases (PKs) and…

HDAC inhibition modulates hippocampus-dependent long-term memory for object location in a CBP-dependent manner

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Haettig, Jakob; Stefanko, Daniel P.; Multani, Monica L.; Figueroa, Dario X.; McQuown, Susan C.; Wood, Marcelo A.

2011-01-01

Transcription of genes required for long-term memory not only involves transcription factors, but also enzymatic protein complexes that modify chromatin structure. Chromatin-modifying enzymes, such as the histone acetyltransferase (HAT) CREB (cyclic-AMP response element binding) binding protein (CBP), are pivotal for the transcriptional regulation required for long-term memory. Several studies have shown that CBP and histone acetylation are necessary for hippocampus-dependent long-term memory and hippocampal long-term potentiation (LTP). Importantly, every genetically modified Cbp mutant mouse exhibits long-term memory impairments in object recognition. However, the role of the hippocampus in object recognition is controversial. To better understand how chromatin-modifying enzymes modulate long-term memory for object recognition, we first examined the role of the hippocampus in retrieval of long-term memory for object recognition or object location. Muscimol inactivation of the dorsal hippocampus prior to retrieval had no effect on long-term memory for object recognition, but completely blocked long-term memory for object location. This was consistent with experiments showing that muscimol inactivation of the hippocampus had no effect on long-term memory for the object itself, supporting the idea that the hippocampus encodes spatial information about an object (such as location or context), whereas cortical areas (such as the perirhinal or insular cortex) encode information about the object itself. Using location-dependent object recognition tasks that engage the hippocampus, we demonstrate that CBP is essential for the modulation of long-term memory via HDAC inhibition. Together, these results indicate that HDAC inhibition modulates memory in the hippocampus via CBP and that different brain regions utilize different chromatin-modifying enzymes to regulate learning and memory. PMID:21224411

The induction of the oxidative burst in Elodea densa by sulfhydryl reagent does not depend on de novo protein synthesis

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Amicucci, Enrica [Milan, Univ. (Italy). Dipt. di Fisiologia e Biochimica delle Piante

1997-12-31

In Elodea densa Planchon leaves, N-ethylmaleimide (NEM) and other sulfhydryl-binding reagents induce a marked and temporary increase of respiration that is insensitive to cyanide, hydroxamate and propylgallate and completely inhibited by diphenylene iodonium (DPI) and by quinacrine. In this paper the author investigates whether the mechanism that causes the oxidative burst depends on the activation of preexisting oxidative systems or on the activation of de novo protein synthesis. The inhibitors used were cycloheximide (CHI) which inhibits protein synthesis in plant cells by depressing the incorporation of aminoacids into proteins and cordycepin, an effective inhibitor of mRNA synthesis. The data support the idea that the mechanism investigated depends on the activation of a long lived protein(s) and not on de novo protein synthesis.

Interaction of Inhibitory and Facilitatory Effects of Conditioning Trials on Long-Term Memory Formation

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Hosono, Shouhei; Matsumoto, Yukihisa; Mizunami, Makoto

2016-01-01

Animals learn through experience and consolidate the memories into long-time storage. Conditioning parameters to induce protein synthesis-dependent long-term memory (LTM) have been the subject of extensive studies in many animals. Here we found a case in which a conditioning trial inhibits or facilitates LTM formation depending on the intervals…

Long-term rates of mitochondrial protein synthesis are increased in mouse skeletal muscle with high-fat feeding regardless of insulin-sensitizing treatment.

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Newsom, Sean A; Miller, Benjamin F; Hamilton, Karyn L; Ehrlicher, Sarah E; Stierwalt, Harrison D; Robinson, Matthew M

2017-11-01

Skeletal muscle mitochondrial protein synthesis is regulated in part by insulin. The development of insulin resistance with diet-induced obesity may therefore contribute to impairments to protein synthesis and decreased mitochondrial respiration. Yet the impact of diet-induced obesity and insulin resistance on mitochondrial energetics is controversial, with reports varying from decreases to increases in mitochondrial respiration. We investigated the impact of changes in insulin sensitivity on long-term rates of mitochondrial protein synthesis as a mechanism for changes to mitochondrial respiration in skeletal muscle. Insulin resistance was induced in C57BL/6J mice using 4 wk of a high-fat compared with a low-fat diet. For 8 additional weeks, diets were enriched with pioglitazone to restore insulin sensitivity compared with nonenriched control low-fat or high-fat diets. Skeletal muscle mitochondrial protein synthesis was measured using deuterium oxide labeling during weeks 10-12 High-resolution respirometry was performed using palmitoyl-l-carnitine, glutamate+malate, and glutamate+malate+succinate as substrates for mitochondria isolated from quadriceps. Mitochondrial protein synthesis and palmitoyl- l-carnitine oxidation were increased in mice consuming a high-fat diet, regardless of differences in insulin sensitivity with pioglitazone treatment. There was no effect of diet or pioglitazone treatment on ADP-stimulated respiration or H 2 O 2 emission using glutamate+malate or glutamate+malate+succinate. The results demonstrate no impairments to mitochondrial protein synthesis or respiration following induction of insulin resistance. Instead, mitochondrial protein synthesis was increased with a high-fat diet and may contribute to remodeling of the mitochondria to increase lipid oxidation capacity. Mitochondrial adaptations with a high-fat diet appear driven by nutrient availability, not intrinsic defects that contribute to insulin resistance. Copyright © 2017 the

Calcium/Calmodulin-dependent Protein Kinase II is a Ubiquitous Molecule in Human Long-term Memory Synaptic Plasticity: A Systematic Review

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Ataei, Negar; Sabzghabaee, Ali Mohammad; Movahedian, Ahmad

2015-01-01

Background: Long-term memory is based on synaptic plasticity, a series of biochemical mechanisms include changes in structure and proteins of brain's neurons. In this article, we systematically reviewed the studies that indicate calcium/calmodulin kinase II (CaMKII) is a ubiquitous molecule among different enzymes involved in human long-term memory and the main downstream signaling pathway of long-term memory. Methods: All of the observational, case–control and review studies were considered and evaluated by the search engines PubMed, Cochrane Central Register of Controlled Trials and ScienceDirect Scopus between 1990 and February 2015. We did not carry out meta-analysis. Results: At the first search, it was fined 1015 articles which included “synaptic plasticity” OR “neuronal plasticity” OR “synaptic density” AND memory AND “molecular mechanism” AND “calcium/calmodulin-dependent protein kinase II” OR CaMKII as the keywords. A total of 335 articles were duplicates in the databases and eliminated. A total of 680 title articles were evaluated. Finally, 40 articles were selected as reference. Conclusions: The studies have shown the most important intracellular signal of long-term memory is calcium-dependent signals. Calcium linked calmodulin can activate CaMKII. After receiving information for learning and memory, CaMKII is activated by Glutamate, the most important neurotransmitter for memory-related plasticity. Glutamate activates CaMKII and it plays some important roles in synaptic plasticity modification and long-term memory. PMID:26445635

Role of Proteasome-Dependent Protein Degradation in Long-Term Operant Memory in "Aplysia"

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Lyons, Lisa C.; Gardner, Jacob S.; Gandour, Catherine E.; Krishnan, Harini C.

2017-01-01

We investigated the in vivo role of protein degradation during intermediate (ITM) and long-term memory (LTM) in "Aplysia" using an operant learning paradigm. The proteasome inhibitor MG-132 inhibited the induction and molecular consolidation of LTM with no effect on ITM. Remarkably, maintenance of steady-state protein levels through…

ROLE OF NEUROTRANSMITTERS AND PROTEIN SYNTHESIS IN SHORT- AND LONG-TERM MEMORY

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Bennett, E.L.; Rosenzweig, M.R.; Flood, J.F.

1978-10-01

Anisomycin is an effective inhibitor of cerebral protein synthesis in mice and is also an effective amnestic agent for both passive and active behavioral tasks. From use of anisomycin in combination with a variety of stimulant and depressant drugs, we conclude that the level of arousal following acquisition plays an important role in determining the duration and the rate of the biosynthetic phase of memory formation. While we have interpreted the experiments with anisomycin as evidence for an essential role of protein in memory storage, others have suggested that side effects of inhibitors of protein synthesis on catecholamine metabolism are the main cause of amnesia. Several experiments were therefore done to compare the effects of anisemycin and catecholamine inhibitors on memory. We conclude that anisomycin's principal amnestic mechanism does not involve inhibition of the catecholamine system. The results strengthen our conclusion that protein synthesis is an essential component for longterm memory trace formation. Also, it is suggested that proteins synthesized in the neuronal cell body are used, in conjunction with other molecules, to produce permanent and semi-permanent anatomical changes.

Long-term dependence in exchange rates

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A. Karytinos

2000-01-01

Full Text Available The extent to which exchange rates of four major currencies against the Greek Drachma exhibit long-term dependence is investigated using a R/S analysis testing framework. We show that both classic R/S analysis and the modified R/S statistic if enhanced by bootstrapping techniques can be proven very reliable tools to this end. Our findings support persistence and long-term dependence with non-periodic cycles for the Deutsche Mark and the French Franc series. In addition a noisy chaos explanation is favored over fractional Brownian motion. On the contrary, the US Dollar and British Pound were found to exhibit a much more random behavior and lack of any long-term structure.

Suppression of matrix protein synthesis in endothelial cells by herpes simplex virus is not dependent on viral protein synthesis

International Nuclear Information System (INIS)

Kefalides, N.A.

1986-01-01

The synthesis of matrix proteins by human endothelial cells (EC) in vitro was studied before and at various times after infection with Herpes Simplex virus Type 1 (HSV-1) or 2 (HSV-2). Monolayers of EC were either mock-infected or infected with virus for 1 hr at a multiplicity infection (MOI) of 5 to 20 at 37 0 C. Control and infected cultures were pulse-labeled for 1 or 2 hrs with either [ 14 C]proline or [ 35 S]methionine. Synthesis of labeled matrix proteins was determined by SDS-gel electrophoresis. Suppression of synthesis of fibronectin, Type IV collagen and thrombospondin began as early as 2 hrs and became almost complete by 10 hrs post-infection. The degree of suppression varied with the protein and the virus dose. Suppression of Type IV collagen occurred first followed by that of fibronectin and then thrombospondin. Infection of EC with UV irradiated HSV-1 or HSV-2 resulted in suppression of host-cell protein synthesis as well as viral protein synthesis. Infection with intact virus in the presence of actinomycin-D resulted in suppression of both host-cell and viral protein synthesis. The data indicate that infection of EC with HSV leads to suppression of matrix protein synthesis which does not depend on viral protein synthesis

Anisomycin Injection in Area CA3 of the Hippocampus Impairs Both Short-Term and Long-Term Memories of Contextual Fear

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Remaud, Jessica; Ceccom, Johnatan; Carponcy, Julien; Dugué, Laura; Menchon, Gregory; Pech, Stéphane; Halley, Helene; Francés, Bernard; Dahan, Lionel

2014-01-01

Protein synthesis is involved in the consolidation of short-term memory into long-term memory. Previous electrophysiological data concerning LTP in CA3 suggest that protein synthesis in that region might also be necessary for short-term memory. We tested this hypothesis by locally injecting the protein synthesis inhibitor anisomycin in hippocampal…

[Participation as Target of Social Medicine and Nursing Care: - Legal Definition of Long-Term Care Dependency - Strategies to Prevent Long-Term Care Dependency].

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Nüchtern, Elisabeth; Gansweid, Barbara; Gerber, Hans; von Mittelstaedt, Gert

2017-01-01

Objective: By the "Second Bill to Strengthen Long-Term Care", a new concept of long-term care dependency will be introduced, valid from 2017. Long-term care dependency according to Social Code XI will be defined covering more aspects than today. Therefore, the working group "Nursing Care" of the division "Social Medicine in Practice and Rehabilitation" in the German Society for Social Medicine and Prevention presents their results after working on the social medicine perspective of the definition and prevention of long-term care dependency. Methods: Both the definition and strategies to prevent long-term care dependency are systematically taken into consideration from the point of view of social medicine on the basis of the International Classification of Functioning, Disability and Health (ICF), as long-term care dependency means a defined condition of disability. Results: Both the current and the new concept of long-term care dependency focus activity limitations. The perspective of social medicine considers the interactions of health condition, its effects on daily activities and personal as well as environmental factors. From this point of view approaches for social benefits concerning prevention and rehabilitation can be identified systematically so as to work against the development and progression of long-term care dependency. The reference to the ICF can facilitate the communication between different professions. The new "graduation" of long-term care dependency would allow an international "translation" referring to the ICF. Conclusion: Experts from the field of social medicine as well as those of nursing care, care-givers and nursing researchers have in common the objective that persons in need of nursing care can participate in as many aspects of life of importance to them in an autonomous and self-determined way. The point of view of social medicine on long-term care dependency is fundamental for all occupational groups that are involved and for their

A Critical Role for the Nucleus Reuniens in Long-Term, But Not Short-Term Associative Recognition Memory Formation.

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Barker, Gareth R I; Warburton, Elizabeth Clea

2018-03-28

Recognition memory for single items requires the perirhinal cortex (PRH), whereas recognition of an item and its associated location requires a functional interaction among the PRH, hippocampus (HPC), and medial prefrontal cortex (mPFC). Although the precise mechanisms through which these interactions are effected are unknown, the nucleus reuniens (NRe) has bidirectional connections with each regions and thus may play a role in recognition memory. Here we investigated, in male rats, whether specific manipulations of NRe function affected performance of recognition memory for single items, object location, or object-in-place associations. Permanent lesions in the NRe significantly impaired long-term, but not short-term, object-in-place associative recognition memory, whereas single item recognition memory and object location memory were unaffected. Temporary inactivation of the NRe during distinct phases of the object-in-place task revealed its importance in both the encoding and retrieval stages of long-term associative recognition memory. Infusions of specific receptor antagonists showed that encoding was dependent on muscarinic and nicotinic cholinergic neurotransmission, whereas NMDA receptor neurotransmission was not required. Finally, we found that long-term object-in-place memory required protein synthesis within the NRe. These data reveal a specific role for the NRe in long-term associative recognition memory through its interactions with the HPC and mPFC, but not the PRH. The delay-dependent involvement of the NRe suggests that it is not a simple relay station between brain regions, but, rather, during high mnemonic demand, facilitates interactions between the mPFC and HPC, a process that requires both cholinergic neurotransmission and protein synthesis. SIGNIFICANCE STATEMENT Recognizing an object and its associated location, which is fundamental to our everyday memory, requires specific hippocampal-cortical interactions, potentially facilitated by the

The relationship between protein synthesis and protein degradation in object recognition memory.

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Furini, Cristiane R G; Myskiw, Jociane de C; Schmidt, Bianca E; Zinn, Carolina G; Peixoto, Patricia B; Pereira, Luiza D; Izquierdo, Ivan

2015-11-01

For decades there has been a consensus that de novo protein synthesis is necessary for long-term memory. A second round of protein synthesis has been described for both extinction and reconsolidation following an unreinforced test session. Recently, it was shown that consolidation and reconsolidation depend not only on protein synthesis but also on protein degradation by the ubiquitin-proteasome system (UPS), a major mechanism responsible for protein turnover. However, the involvement of UPS on consolidation and reconsolidation of object recognition memory remains unknown. Here we investigate in the CA1 region of the dorsal hippocampus the involvement of UPS-mediated protein degradation in consolidation and reconsolidation of object recognition memory. Animals with infusion cannulae stereotaxically implanted in the CA1 region of the dorsal hippocampus, were exposed to an object recognition task. The UPS inhibitor β-Lactacystin did not affect the consolidation and the reconsolidation of object recognition memory at doses known to affect other forms of memory (inhibitory avoidance, spatial learning in a water maze) while the protein synthesis inhibitor anisomycin impaired the consolidation and the reconsolidation of the object recognition memory. However, β-Lactacystin was able to reverse the impairment caused by anisomycin on the reconsolidation process in the CA1 region of the hippocampus. Therefore, it is possible to postulate a direct link between protein degradation and protein synthesis during the reconsolidation of the object recognition memory. Copyright © 2015 Elsevier B.V. All rights reserved.

The differential role of cortical protein synthesis in taste memory formation and persistence

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Levitan, David; Gal-Ben-Ari, Shunit; Heise, Christopher; Rosenberg, Tali; Elkobi, Alina; Inberg, Sharon; Sala, Carlo; Rosenblum, Kobi

2016-05-01

The current dogma suggests that the formation of long-term memory (LTM) is dependent on protein synthesis but persistence of the memory trace is not. However, many of the studies examining the effect of protein synthesis inhibitors (PSIs) on LTM persistence were performed in the hippocampus, which is known to have a time-dependent role in memory storage, rather than the cortex, which is considered to be the main structure to store long-term memories. Here we studied the effect of PSIs on LTM formation and persistence in male Wistar Hola (n⩾5) rats by infusing the protein synthesis inhibitor, anisomycin (100 μg, 1 μl), into the gustatory cortex (GC) during LTM formation and persistence in conditioned taste aversion (CTA). We found that local anisomycin infusion to the GC before memory acquisition impaired LTM formation (P=8.9E-5), but had no effect on LTM persistence when infused 3 days post acquisition (P=0.94). However, when we extended the time interval between treatment with anisomycin and testing from 3 days to 14 days, LTM persistence was enhanced (P=0.01). The enhancement was on the background of stable and non-declining memory, and was not recapitulated by another amnesic agent, APV (10 μg, 1 μl), an N-methyl-D-aspartate receptor antagonist (P=0.54). In conclusion, CTA LTM remains sensitive to the action of PSIs in the GC even 3 days following memory acquisition. This sensitivity is differentially expressed between the formation and persistence of LTM, suggesting that increased cortical protein synthesis promotes LTM formation, whereas decreased protein synthesis promotes LTM persistence.

Safe taste memory consolidation is disrupted by a protein synthesis inhibitor in the nucleus accumbens shell.

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Pedroza-Llinás, R; Ramírez-Lugo, L; Guzmán-Ramos, K; Zavala-Vega, S; Bermúdez-Rattoni, F

2009-07-01

Consolidation is the process by which a new memory is stabilized over time, and is dependent on de novo protein synthesis. A useful model for studying memory formation is gustatory memory, a type of memory in which a novel taste may become either safe by not being followed by negative consequences (attenuation of neophobia, AN), or aversive by being followed by post-digestive malaise (conditioned taste aversion, CTA). Here we evaluated the effects of the administration of a protein synthesis inhibitor in the nucleus accumbens (NAc) shell for either safe or aversive taste memory trace consolidation. To test the effects on CTA and AN of protein synthesis inhibition, anisomycin (100microg/microl) was bilaterally infused into the NAc shell of Wistar rats' brains. We found that post-trial protein synthesis blockade impaired the long-term safe taste memory. However, protein synthesis inhibition failed to disrupt the long-term memory of CTA. In addition, we infused anisomycin in the NAc shell after the pre-exposure to saccharin in a latent inhibition of aversive taste. We found that the protein synthesis inhibition impaired the consolidation of safe taste memory, allowing the aversive taste memory to form and consolidate. Our results suggest that protein synthesis is required in the NAc shell for consolidation of safe but not aversive taste memories, supporting the notion that consolidation of taste memory is processed in several brain regions in parallel, and implying that inhibitory interactions between both taste memory traces do occur.

Transcriptional regulation of long-term memory in the marine snail Aplysia

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Lee Yong-Seok

2008-06-01

Full Text Available Abstract Whereas the induction of short-term memory involves only covalent modifications of constitutively expressed preexisting proteins, the formation of long-term memory requires gene expression, new RNA, and new protein synthesis. On the cellular level, transcriptional regulation is thought to be the starting point for a series of molecular steps necessary for both the initiation and maintenance of long-term synaptic facilitation (LTF. The core molecular features of transcriptional regulation involved in the long-term process are evolutionally conserved in Aplysia, Drosophila, and mouse, and indicate that gene regulation by the cyclic AMP response element binding protein (CREB acting in conjunction with different combinations of transcriptional factors is critical for the expression of many forms of long-term memory. In the marine snail Aplysia, the molecular mechanisms that underlie the storage of long-term memory have been extensively studied in the monosynaptic connections between identified sensory neuron and motor neurons of the gill-withdrawal reflex. One tail shock or one pulse of serotonin (5-HT, a modulatory transmitter released by tail shocks, produces a transient facilitation mediated by the cAMP-dependent protein kinase leading to covalent modifications in the sensory neurons that results in an enhancement of transmitter release and a strengthening of synaptic connections lasting minutes. By contrast, repeated pulses of 5-hydroxytryptamine (5-HT induce a transcription- and translation-dependent long-term facilitation (LTF lasting more than 24 h and trigger the activation of a family of transcription factors in the presynaptic sensory neurons including ApCREB1, ApCREB2 and ApC/EBP. In addition, we have recently identified novel transcription factors that modulate the expression of ApC/EBP and also are critically involved in LTF. In this review, we examine the roles of these transcription factors during consolidation of LTF induced

Transcriptional regulation of long-term memory in the marine snail Aplysia.

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Lee, Yong-Seok; Bailey, Craig H; Kandel, Eric R; Kaang, Bong-Kiun

2008-06-17

Whereas the induction of short-term memory involves only covalent modifications of constitutively expressed preexisting proteins, the formation of long-term memory requires gene expression, new RNA, and new protein synthesis. On the cellular level, transcriptional regulation is thought to be the starting point for a series of molecular steps necessary for both the initiation and maintenance of long-term synaptic facilitation (LTF). The core molecular features of transcriptional regulation involved in the long-term process are evolutionally conserved in Aplysia, Drosophila, and mouse, and indicate that gene regulation by the cyclic AMP response element binding protein (CREB) acting in conjunction with different combinations of transcriptional factors is critical for the expression of many forms of long-term memory. In the marine snail Aplysia, the molecular mechanisms that underlie the storage of long-term memory have been extensively studied in the monosynaptic connections between identified sensory neuron and motor neurons of the gill-withdrawal reflex. One tail shock or one pulse of serotonin (5-HT), a modulatory transmitter released by tail shocks, produces a transient facilitation mediated by the cAMP-dependent protein kinase leading to covalent modifications in the sensory neurons that results in an enhancement of transmitter release and a strengthening of synaptic connections lasting minutes. By contrast, repeated pulses of 5-hydroxytryptamine (5-HT) induce a transcription- and translation-dependent long-term facilitation (LTF) lasting more than 24 h and trigger the activation of a family of transcription factors in the presynaptic sensory neurons including ApCREB1, ApCREB2 and ApC/EBP. In addition, we have recently identified novel transcription factors that modulate the expression of ApC/EBP and also are critically involved in LTF. In this review, we examine the roles of these transcription factors during consolidation of LTF induced by different

A role for autophagy in long-term spatial memory formation in male rodents.

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Hylin, Michael J; Zhao, Jing; Tangavelou, Karthikeyan; Rozas, Natalia S; Hood, Kimberly N; MacGowan, Jacalyn S; Moore, Anthony N; Dash, Pramod K

2018-03-01

A hallmark of long-term memory formation is the requirement for protein synthesis. Administration of protein synthesis inhibitors impairs long-term memory formation without influencing short-term memory. Rapamycin is a specific inhibitor of target of rapamycin complex 1 (TORC1) that has been shown to block protein synthesis and impair long-term memory. In addition to regulating protein synthesis, TORC1 also phosphorylates Unc-51-like autophagy activating kinase-1 (Ulk-1) to suppress autophagy. As autophagy can be activated by rapamycin (and rapamycin inhibits long-term memory), our aim was to test the hypothesis that autophagy inhibitors would enhance long-term memory. To examine if learning alters autophagosome number, we used male reporter mice carrying the GFP-LC3 transgene. Using these mice, we observed that training in the Morris water maze task increases the number of autophagosomes, a finding contrary to our expectations. For learning and memory studies, male Long Evans rats were used due to their relatively larger size (compared to mice), making it easier to perform intrahippocampal infusions in awake, moving animals. When the autophagy inhibitors 3-methyladenine (3-MA) or Spautin-1 were administered bilaterally into the hippocampii prior to training in the Morris water maze task, the drugs did not alter learning. In contrast, when memory was tested 24 hours later by a probe trial, significant impairments were observed. In addition, intrahippocampal infusion of an autophagy activator peptide (TAT-Beclin-1) improved long-term memory. These results indicate that autophagy is not necessary for learning, but is required for long-term memory formation. © 2017 Wiley Periodicals, Inc.

Reconsolidation of long-term memory in Aplysia.

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Cai, Diancai; Pearce, Kaycey; Chen, Shanping; Glanzman, David L

2012-10-09

When an animal is reminded of a prior experience and shortly afterward treated with a protein synthesis inhibitor, the consolidated memory for the experience can be disrupted; by contrast, protein synthesis inhibition without prior reminding commonly does not disrupt long-term memory [1-3]. Such results imply that the reminding triggers reconsolidation of the memory. Here, we asked whether the behavioral and synaptic changes associated with the memory for long-term sensitization (LTS) of the siphon-withdrawal reflex in the marine snail Aplysia californica [4, 5] could undergo reconsolidation. In support of this idea, we found that when sensitized animals were given abbreviated reminder sensitization training 48-96 hr after the original sensitization training, followed by treatment with the protein synthesis inhibitor anisomycin, LTS was disrupted. We also found that long-term (≥ 24 hr) facilitation (LTF) [6], which can be induced in the monosynaptic connection between Aplysia sensory and motor neurons in dissociated cell culture by multiple spaced pulses of the endogenous facilitatory transmitter serotonin (5-HT) [7, 8], could be eliminated by treating the synapses with one reminder pulse of 5-HT, followed by anisomycin, at 48 hr after the original training. Our results provide a simple model system for understanding the synaptic basis of reconsolidation. Copyright © 2012 Elsevier Ltd. All rights reserved.

Insulin signaling is acutely required for long-term memory in Drosophila.

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Chambers, Daniel B; Androschuk, Alaura; Rosenfelt, Cory; Langer, Steven; Harding, Mark; Bolduc, Francois V

2015-01-01

Memory formation has been shown recently to be dependent on energy status in Drosophila. A well-established energy sensor is the insulin signaling (InS) pathway. Previous studies in various animal models including human have revealed the role of insulin levels in short-term memory but its role in long-term memory remains less clear. We therefore investigated genetically the spatial and temporal role of InS using the olfactory learning and long-term memory model in Drosophila. We found that InS is involved in both learning and memory. InS in the mushroom body is required for learning and long-term memory whereas long-term memory specifically is impaired after InS signaling disruption in the ellipsoid body, where it regulates the level of p70s6k, a downstream target of InS and a marker of protein synthesis. Finally, we show also that InS is acutely required for long-term memory formation in adult flies.

A cost of long-term memory in Drosophila

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Mery, Frederic; Kawecki, Tadeusz J.

2005-01-01

Two distinct forms of consolidated associative memory are known in Drosophila: long-term memory and so-called anesthesia-resistant memory. Long-term memory is more stable, but unlike anesthesia-resistant memory, its formation requires protein synthesis. We show that flies induced to form long-term memory become more susceptible to extreme stress (such as desiccation). In contrast, induction of anesthesia-resistant memory had no detectable effect on desiccation resistance. This finding may hel...

Intrahippocampal Glutamine Administration Inhibits mTORC1 Signaling and Impairs Long-Term Memory

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Rozas, Natalia S.; Redell, John B.; Pita-Almenar, Juan D.; McKenna, James, III.; Moore, Anthony N.; Gambello, Michael J.; Dash, Pramod K.

2015-01-01

The mechanistic Target of Rapamycin Complex 1 (mTORC1), a key regulator of protein synthesis and cellular growth, is also required for long-term memory formation. Stimulation of mTORC1 signaling is known to be dependent on the availability of energy and growth factors, as well as the presence of amino acids. In vitro studies using serum- and amino…

Predictors of muscle protein synthesis after severe pediatric burns.

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Diaz, Eva C; Herndon, David N; Lee, Jinhyung; Porter, Craig; Cotter, Matthew; Suman, Oscar E; Sidossis, Labros S; Børsheim, Elisabet

2015-04-01

Following a major burn, skeletal muscle protein synthesis rate increases but is often insufficient to compensate for massively elevated muscle protein breakdown rates. Given the long-term nature of the pathophysiologic response to burn injury, we hypothesized that muscle protein synthesis rate would be chronically elevated in severely burned children. The objectives of this study were to characterize muscle protein synthesis rate of burned children over a period of 24 months after injury and to identify predictors that influence this response. A total of 87 children with 40% or greater total body surface area (TBSA) burned were included. Patients participated in stable isotope infusion studies at 1, 2, and approximately 4 weeks after burn and at 6, 12, and 24 months after injury to determine skeletal muscle protein fractional synthesis rate. Generalized estimating equations with log link normal distribution were applied to account for clustering of patients and control for patient characteristics. Patients (8 ± 6 years) had large (62, 51-72% TBSA) and deep (47% ± 21% TBSA third degree) burns. Muscle protein fractional synthesis rate was elevated throughout the first 12 months after burn compared with established values from healthy young adults. Muscle protein fractional synthesis rate was lower in boys, in children older than 3 years, and when burns were greater than 80% TBSA. Muscle protein synthesis is elevated for at least 1 year after injury, suggesting that greater muscle protein turnover is a component of the long-term pathophysiologic response to burn trauma. Muscle protein synthesis is highly affected by sex, age, and burn size in severely burned children. These findings may explain the divergence in net protein balance and lean body mass in different populations of burn patients. Prognostic study, level III.

Transforming Growth Factor ß Recruits Persistent MAPK Signaling to Regulate Long-Term Memory Consolidation in "Aplysia Californica"

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Shobe, Justin; Philips, Gary T.; Carew, Thomas J.

2016-01-01

In this study, we explore the mechanistic relationship between growth factor signaling and kinase activity that supports the protein synthesis-dependent phase of long-term memory (LTM) consolidation for sensitization of "Aplysia." Specifically, we examine LTM for tail shock-induced sensitization of the tail-elicited siphon withdrawal…

Neo-synthesis of estrogenic or androgenic neurosteroids determine whether long-term potentiation or depression is induced in hippocampus of male rat.

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Di Mauro, Michela; Tozzi, Alessandro; Calabresi, Paolo; Pettorossi, Vito Enrico; Grassi, Silvarosa

2015-01-01

Estrogenic and androgenic steroids synthesized in the brain may rapidly modulate synaptic plasticity interacting with specific membrane receptors. We explored by electrophysiological recordings in hippocampal slices of male rat the influence of 17β-estradiol (E2) and 5α-dihydrotestosterone (DHT) neo-synthesis on the synaptic changes induced in the CA1 region. Induction of long-term depression (LTD) and depotentiation (DP) by low frequency stimulation (LFS, 15 min-1 Hz) and of long-term potentiation (LTP) by high frequency stimulation (HFS, 1 s-100 Hz), medium (MFS, 1 s-50 Hz), or weak (WFS, 1 s-25 Hz) frequency stimulation was assayed under inhibitors of enzymes converting testosterone (T) into DHT (5α-reductase) and T into E2 (P450-aromatase). We found that LFS-LTD depends on DHT synthesis, since it was fully prevented under finasteride, an inhibitor of DHT synthesis, and rescued by exogenous DHT, while the E2 synthesis was not involved. Conversely, the full development of HFS-LTP requires the synthesis of E2, as demonstrated by the LTP reduction observed under letrozole, an inhibitor of E2 synthesis, and its full rescue by exogenous E2. For intermediate stimulation protocols DHT, but not E2 synthesis, was involved in the production of a small LTP induced by WFS, while the E2 synthesis was required for the MFS-dependent LTP. Under the combined block of DHT and E2 synthesis all stimulation frequencies induced partial LTP. Overall, these results indicate that DHT is required for converting the partial LTP into LTD whereas E2 is needed for the full expression of LTP, evidencing a key role of the neo-synthesis of sex neurosteroids in determining the direction of synaptic long-term effects.

Neo-synthesis of estrogenic or androgenic neurosteroids determine whether long-term potentiation or depression is induced in hippocampus of male rat

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Michela eDi Mauro

2015-10-01

Full Text Available Estrogenic and androgenic steroids synthesized in the brain may rapidly modulate synaptic plasticity interacting with specific membrane receptors. We explored by electrophysiological recordings in hippocampal slices of male rat the influence of 17b-estradiol (E2 and 5a-dihydrotestosterone (DHT neo-synthesis on the synaptic changes induced in the CA1 region. Induction of long-term depression (LTD and depotentiation (DP by low frequency stimulation (LFS, 15 min-1 Hz and of long-term potentiation (LTP by high (HFS, 1 s-100 Hz, medium (MFS, 1 s-50 Hz, or weak (WFS, 1 s-25 Hz frequency stimulation was assayed under inhibitors of enzymes converting testosterone (T into DHT (5a-reductase and T into E2 (P450-aromatase. We found that LFS-LTD depends on DHT synthesis, since it was fully prevented under finasteride, an inhibitor of DHT synthesis, and rescued by exogenous DHT, while the E2 synthesis was not involved. Conversely, the full development of HFS-LTP requires the synthesis of E2, as demonstrated by the LTP reduction observed under letrozole, an inhibitor of E2 synthesis, and its full rescue by exogenous E2. For intermediate stimulation protocols DHT, but not E2 synthesis, was involved in the production of a small LTP induced by WFS, while the E2 synthesis was required for the MFS-dependent LTP. Under the combined block of DHT and E2 synthesis all stimulation frequencies induced partial LTP. Overall, these results indicate that DHT is required for converting the partial LTP into LTD whereas E2 is needed for the full expression of LTP, evidencing a key role of the neo-synthesis of sex neurosteroids in determining the direction of synaptic long-term effects.

CREB binding protein is required for both short-term and long-term memory formation.

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Chen, Guiquan; Zou, Xiaoyan; Watanabe, Hirotaka; van Deursen, Jan M; Shen, Jie

2010-09-29

CREB binding protein (CBP) is a transcriptional coactivator with histone acetyltransferase activity. Our prior study suggested that CBP might be a key target of presenilins in the regulation of memory formation and neuronal survival. To elucidate the role of CBP in the adult brain, we generated conditional knock-out (cKO) mice in which CBP is completely inactivated in excitatory neurons of the postnatal forebrain. Histological analysis revealed normal neuronal morphology and absence of age-dependent neuronal degeneration in the CBP cKO cerebral cortex. CBP cKO mice exhibited robust impairment in the formation of spatial, associative, and object-recognition memory. In addition to impaired long-term memory, CBP cKO mice also displayed deficits in short-term associative and object-recognition memory. Administration of a histone deacetylase inhibitor, trichostatin A, rescued the reduction of acetylated histones in the CBP cKO cortex but failed to rescue either short- or long-term memory deficits, suggesting that the memory impairment may not be caused by general reduction of histone acetyltransferase activity in CBP cKO mice. Further microarray and Western analysis showed decreased expression of calcium-calmodulin-dependent kinase isoforms and NMDA and AMPA receptor subunits in the cerebral cortex of CBP cKO mice. Collectively, these findings suggest a crucial role for CBP in the formation of both short- and long-term memory.

Molecular constraints on synaptic tagging and maintenance of long-term potentiation: a predictive model.

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Smolen, Paul; Baxter, Douglas A; Byrne, John H

2012-01-01

Protein synthesis-dependent, late long-term potentiation (LTP) and depression (LTD) at glutamatergic hippocampal synapses are well characterized examples of long-term synaptic plasticity. Persistent increased activity of protein kinase M ζ (PKMζ) is thought essential for maintaining LTP. Additional spatial and temporal features that govern LTP and LTD induction are embodied in the synaptic tagging and capture (STC) and cross capture hypotheses. Only synapses that have been "tagged" by a stimulus sufficient for LTP and learning can "capture" PKMζ. A model was developed to simulate the dynamics of key molecules required for LTP and LTD. The model concisely represents relationships between tagging, capture, LTD, and LTP maintenance. The model successfully simulated LTP maintained by persistent synaptic PKMζ, STC, LTD, and cross capture, and makes testable predictions concerning the dynamics of PKMζ. The maintenance of LTP, and consequently of at least some forms of long-term memory, is predicted to require continual positive feedback in which PKMζ enhances its own synthesis only at potentiated synapses. This feedback underlies bistability in the activity of PKMζ. Second, cross capture requires the induction of LTD to induce dendritic PKMζ synthesis, although this may require tagging of a nearby synapse for LTP. The model also simulates the effects of PKMζ inhibition, and makes additional predictions for the dynamics of CaM kinases. Experiments testing the above predictions would significantly advance the understanding of memory maintenance.

Long-term aversive taste memory requires insular and amygdala protein degradation.

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Rodriguez-Ortiz, Carlos J; Balderas, Israela; Saucedo-Alquicira, Fernando; Cruz-Castañeda, Paulina; Bermudez-Rattoni, Federico

2011-03-01

Some reports have shown that the ubiquitin-proteasome system (UPS) is necessary to degrade repressor factors to produce new proteins essential to memory consolidation. Furthermore, recent evidence suggests that memory updating also relies on protein degradation through the UPS. To evaluate whether degradation of proteins is part of the cellular events needed for long-term storage of taste aversion, we injected lactacystin--an UPS inhibitor--into the amygdala and/or insular cortex 30 min before the first or second training trials. The results revealed that degradation of proteins in either the amygdala or insular cortex suffices for long-term stabilization of first-time encounter taste aversion. On the other hand, lactacystin applied in the insula, but not in the amygdala, before the second training prevented long-term storage of updated information. Our results support that degradation of proteins by means of the UPS is required every time taste aversion is to be stored in long-term memory. Copyright © 2010 Elsevier Inc. All rights reserved.

Social Recognition Memory Requires Two Stages of Protein Synthesis in Mice

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Wolf, Gerald; Engelmann, Mario; Richter, Karin

2005-01-01

Olfactory recognition memory was tested in adult male mice using a social discrimination task. The testing was conducted to begin to characterize the role of protein synthesis and the specific brain regions associated with activity in this task. Long-term olfactory recognition memory was blocked when the protein synthesis inhibitor anisomycin was…

Parametric and genetic analysis of Drosophila appetitive long-term memory and sugar motivation.

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Colomb, J; Kaiser, L; Chabaud, M-A; Preat, T

2009-06-01

Distinct forms of memory can be highlighted using different training protocols. In Drosophila olfactory aversive learning, one conditioning session triggers memory formation independently of protein synthesis, while five spaced conditioning sessions lead to the formation of long-term memory (LTM), a long-lasting memory dependent on de novo protein synthesis. In contrast, one session of odour-sugar association appeared sufficient for the fly to form LTM. We designed and tuned an apparatus that facilitates repeated discriminative conditioning by alternate presentations of two odours, one being associated with sugar, as well as a new paradigm to test sugar responsiveness (SR). Our results show that both SR and short-term memory (STM) scores increase with starvation length before conditioning. The protein dependency of appetitive LTM is independent of the repetition and the spacing of training sessions, on the starvation duration and on the strength of the unconditioned stimulus. In contrast to a recent report, our test measures an abnormal SR of radish mutant flies, which might initiate their STM and LTM phenotypes. In addition, our work shows that crammer and tequila mutants, which are deficient for aversive LTM, present both an SR and an appetitive STM defect. Using the MB247-P[switch] system, we further show that tequila is required in the adult mushroom bodies for normal sugar motivation.

Underlying Mechanisms of Cooperativity, Input Specificity, and Associativity of Long-Term Potentiation Through a Positive Feedback of Local Protein Synthesis

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Lijie Hao

2018-05-01

Full Text Available Long-term potentiation (LTP is a specific form of activity-dependent synaptic plasticity that is a leading mechanism of learning and memory in mammals. The properties of cooperativity, input specificity, and associativity are essential for LTP; however, the underlying mechanisms are unclear. Here, based on experimentally observed phenomena, we introduce a computational model of synaptic plasticity in a pyramidal cell to explore the mechanisms responsible for the cooperativity, input specificity, and associativity of LTP. The model is based on molecular processes involved in synaptic plasticity and integrates gene expression involved in the regulation of neuronal activity. In the model, we introduce a local positive feedback loop of protein synthesis at each synapse, which is essential for bimodal response and synapse specificity. Bifurcation analysis of the local positive feedback loop of brain-derived neurotrophic factor (BDNF signaling illustrates the existence of bistability, which is the basis of LTP induction. The local bifurcation diagram provides guidance for the realization of LTP, and the projection of whole system trajectories onto the two-parameter bifurcation diagram confirms the predictions obtained from bifurcation analysis. Moreover, model analysis shows that pre- and postsynaptic components are required to achieve the three properties of LTP. This study provides insights into the mechanisms underlying the cooperativity, input specificity, and associativity of LTP, and the further construction of neural networks for learning and memory.

Sleep deprivation impairs memory by attenuating mTORC1-dependent protein synthesis.

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Tudor, Jennifer C; Davis, Emily J; Peixoto, Lucia; Wimmer, Mathieu E; van Tilborg, Erik; Park, Alan J; Poplawski, Shane G; Chung, Caroline W; Havekes, Robbert; Huang, Jiayan; Gatti, Evelina; Pierre, Philippe; Abel, Ted

2016-04-26

Sleep deprivation is a public health epidemic that causes wide-ranging deleterious consequences, including impaired memory and cognition. Protein synthesis in hippocampal neurons promotes memory and cognition. The kinase complex mammalian target of rapamycin complex 1 (mTORC1) stimulates protein synthesis by phosphorylating and inhibiting the eukaryotic translation initiation factor 4E-binding protein 2 (4EBP2). We investigated the involvement of the mTORC1-4EBP2 axis in the molecular mechanisms mediating the cognitive deficits caused by sleep deprivation in mice. Using an in vivo protein translation assay, we found that loss of sleep impaired protein synthesis in the hippocampus. Five hours of sleep loss attenuated both mTORC1-mediated phosphorylation of 4EBP2 and the interaction between eukaryotic initiation factor 4E (eIF4E) and eIF4G in the hippocampi of sleep-deprived mice. Increasing the abundance of 4EBP2 in hippocampal excitatory neurons before sleep deprivation increased the abundance of phosphorylated 4EBP2, restored the amount of eIF4E-eIF4G interaction and hippocampal protein synthesis to that seen in mice that were not sleep-deprived, and prevented the hippocampus-dependent memory deficits associated with sleep loss. These findings collectively demonstrate that 4EBP2-regulated protein synthesis is a critical mediator of the memory deficits caused by sleep deprivation. Copyright © 2016, American Association for the Advancement of Science.

A Protein Synthesis and Nitric Oxide-Dependent Presynaptic Enhancement in Persistent Forms of Long-Term Potentiation

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Johnstone, Victoria P. A.; Raymond, Clarke R.

2011-01-01

Long-term potentiation (LTP) is an important process underlying learning and memory in the brain. At CA3-CA1 synapses in the hippocampus, three discrete forms of LTP (LTP1, 2, and 3) can be differentiated on the basis of maintenance and induction mechanisms. However, the relative roles of pre- and post-synaptic expression mechanisms in LTP1, 2,…

Predictors of muscle protein synthesis after severe pediatric burns

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Objectives: Following a major burn, muscle protein synthesis rate increases but in most patients, this response is not sufficient to compensate the also elevated protein breakdown. Given the long-term nature of the pathophysiologic response to burn injury, we hypothesized that skeletal muscle prot...

Long-term outcome in pyridoxine-dependent epilepsy

NARCIS (Netherlands)

Bok, L.A.; Halbertsma, F.J.; Houterman, S.; Wevers, R.A.; Vreeswijk, C.M.J.M.; Jakobs, C.; Struys, E.; van der Hoeven, J.H.; Sival, D.A.; Willemsen, M.A.

2012-01-01

Aim  The long-term outcome of the Dutch pyridoxine-dependent epilepsy cohort and correlations between patient characteristics and follow-up data were retrospectively studied. Method  Fourteen patients recruited from a national reference laboratory were included (four males, 10 females, from 11

Limitations and possibilities of green synthesis and long-term stability of colloidal Ag nanoparticles

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Velgosová, Oksana; Mražíková, Anna

2017-12-01

In this paper the influence of algae life cycle and the solutions pH on the green synthesis of colloidal Ag nanoparticles (AgNPs) as well as effect of different storage conditions on AgNPs long-term stability was investigated. Silver nanoparticles were biologically synthesized using extracts of Parachlorella kessleri algae cultivated 1, 2, 3 and 4 weeks. The formation of AgNPs was monitored using a UV-vis spectrophotometer and verified by TEM observation. The results confirmed formation of polyhedron and/or near polyhedron AgNPs, ranging between 5 and 60 nm in diameter. The age of algae influenced the synthesis rate and an amount of AgNPs in solution. The best results were obtained using tree weeks old algae. UV-vis analysis and TEM observation also revealed that the size and the stability of AgNPs depend on the pH of solution. AgNPs formed in solutions of higher pH (8 and 10) are polyhedron, fine, with narrow size interval and stabile. Nanoparticles formed in solutions of low pH (2, 4 and 6) started to lose their stability on 10th day of experiment, and the particle size interval was wide. The long-term stability of AgNPs can be influenced by light and temperature conditions. The most significant stability loss was observed at day light and room temperature (21°C). After 200-days significant amount of agglomerated particles settled on the bottom of the Erlenmeyer flask. AgNPs stored at dark and room temperature showed better long-term stability, weak particles agglomeration was observed. AgNPs stored at dark and at temperature 5°C showed the best long-term stability. Such AgNPs remained spherical, fine (5-20 nm), with narrow size interval and stable (no agglomeration) even after more than six months.

Fasting launches CRTC to facilitate long-term memory formation in Drosophila.

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Hirano, Yukinori; Masuda, Tomoko; Naganos, Shintaro; Matsuno, Motomi; Ueno, Kohei; Miyashita, Tomoyuki; Horiuchi, Junjiro; Saitoe, Minoru

2013-01-25

Canonical aversive long-term memory (LTM) formation in Drosophila requires multiple spaced trainings, whereas appetitive LTM can be formed after a single training. Appetitive LTM requires fasting prior to training, which increases motivation for food intake. However, we found that fasting facilitated LTM formation in general; aversive LTM formation also occurred after single-cycle training when mild fasting was applied before training. Both fasting-dependent LTM (fLTM) and spaced training-dependent LTM (spLTM) required protein synthesis and cyclic adenosine monophosphate response element-binding protein (CREB) activity. However, spLTM required CREB activity in two neural populations--mushroom body and DAL neurons--whereas fLTM required CREB activity only in mushroom body neurons. fLTM uses the CREB coactivator CRTC, whereas spLTM uses the coactivator CBP. Thus, flies use distinct LTM machinery depending on their hunger state.

Molecular constraints on synaptic tagging and maintenance of long-term potentiation: a predictive model.

Directory of Open Access Journals (Sweden)

Paul Smolen

Full Text Available Protein synthesis-dependent, late long-term potentiation (LTP and depression (LTD at glutamatergic hippocampal synapses are well characterized examples of long-term synaptic plasticity. Persistent increased activity of protein kinase M ζ (PKMζ is thought essential for maintaining LTP. Additional spatial and temporal features that govern LTP and LTD induction are embodied in the synaptic tagging and capture (STC and cross capture hypotheses. Only synapses that have been "tagged" by a stimulus sufficient for LTP and learning can "capture" PKMζ. A model was developed to simulate the dynamics of key molecules required for LTP and LTD. The model concisely represents relationships between tagging, capture, LTD, and LTP maintenance. The model successfully simulated LTP maintained by persistent synaptic PKMζ, STC, LTD, and cross capture, and makes testable predictions concerning the dynamics of PKMζ. The maintenance of LTP, and consequently of at least some forms of long-term memory, is predicted to require continual positive feedback in which PKMζ enhances its own synthesis only at potentiated synapses. This feedback underlies bistability in the activity of PKMζ. Second, cross capture requires the induction of LTD to induce dendritic PKMζ synthesis, although this may require tagging of a nearby synapse for LTP. The model also simulates the effects of PKMζ inhibition, and makes additional predictions for the dynamics of CaM kinases. Experiments testing the above predictions would significantly advance the understanding of memory maintenance.

A quantitative analysis of 2-D gels identifies proteins in which labeling is increased following long-term sensitization in Aplysia

International Nuclear Information System (INIS)

Castellucci, V.F.; Kennedy, T.E.; Kandel, E.R.; Goelet, P.

1988-01-01

Long-term memory for sensitization of the gill- and siphon-withdrawal reflex in Aplysia, produced by 4 days of training, is associated with increased synaptic efficacy of the connection between the sensory and motor neurons. This training is also accompanied by neuronal growth; there is an increase in the number of synaptic varicosities per sensory neuron and in the number of active zones. Such structural changes may be due to changes in the rates of synthesis of certain proteins. We have searched for proteins in which the rates of [ 35 S]methionine labeling are altered during the maintenance phase of long-term memory for sensitization by using computer-assisted quantitative 2-D gel analysis. This method has allowed us to detect 4 proteins in which labeling is altered after 4 days of sensitization training

Inhibition of protein kinase A activity interferes with long-term, but not short-term, memory of conditioned taste aversions.

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Koh, Ming Teng; Thiele, Todd E; Bernstein, Ilene L

2002-12-01

The present experiments examined whether inhibition of cyclic adenosine monophosphate (cAMP)-dependent protein kinase A (PKA) activity interferes with conditioned taste aversion (CTA) memories. Rats were centrally infused with the selective PKA inhibitor Rp-adenosine 3',5'-cyclic monophosphothioate triethylamine (Rp-cAMPS) before conditioning. Direct infusions of Rp-cAMPS into the amygdala showed no interference with short-term memory but did show significant attenuation of long-term memory and more rapid extinction. Results suggest that PKA activity is involved in the consolidation of long-term memory of CTAs, and that the amygdala may be 1 site that is important for this activity.

Long-Term Outcome in Pyridoxine-Dependent Epilepsy

Science.gov (United States)

Bok, Levinus A.; Halbertsma, Feico J..; Houterman, Saskia; Wevers, Ron A.; Vreeswijk, Charlotte; Jakobs, Cornelis; Struys, Eduard; van der Hoeven, Johan H.; Sival, Deborah A.; Willemsen, Michel A.

2012-01-01

Aim: The long-term outcome of the Dutch pyridoxine-dependent epilepsy cohort and correlations between patient characteristics and follow-up data were retrospectively studied. Method: Fourteen patients recruited from a national reference laboratory were included (four males, 10 females, from 11 families; median age at assessment 6y; range 2y…

Protein synthesis underlies post-retrieval memory consolidation to a restricted degree only when updated information is obtained

OpenAIRE

Rodriguez-Ortiz, Carlos J.; De la Cruz, Vanesa; Gutiérrez, Ranier; Bermudez-Rattoni, Federico

2005-01-01

Consolidation theory proposes that through the synthesis of new proteins recently acquired memories are strengthened over time into a stable long-term memory trace. However, evidence has accumulated suggesting that retrieved memory is susceptible to disruption, seeming to consolidate again (reconsolidate) to be retained in long-term storage. Here we show that intracortical blockade of protein synthesis in the gustatory cortex after retrieval of taste-recognition memory disrupts previously con...

Protein Synthesis Inhibition in the Peri-Infarct Cortex Slows Motor Recovery in Rats.

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Schubring-Giese, Maximilian; Leemburg, Susan; Luft, Andreas Rüdiger; Hosp, Jonas Aurel

2016-01-01

Neuroplasticity and reorganization of brain motor networks are thought to enable recovery of motor function after ischemic stroke. Especially in the cortex surrounding the ischemic scar (i.e., peri-infarct cortex), evidence for lasting reorganization has been found at the level of neurons and networks. This reorganization depends on expression of specific genes and subsequent protein synthesis. To test the functional relevance of the peri-infarct cortex for recovery we assessed the effect of protein synthesis inhibition within this region after experimental stroke. Long-Evans rats were trained to perform a skilled-reaching task (SRT) until they reached plateau performance. A photothrombotic stroke was induced in the forelimb representation of the primary motor cortex (M1) contralateral to the trained paw. The SRT was re-trained after stroke while the protein synthesis inhibitor anisomycin (ANI) or saline were injected into the peri-infarct cortex through implanted cannulas. ANI injections reduced protein synthesis within the peri-infarct cortex by 69% and significantly impaired recovery of reaching performance through re-training. Improvement of motor performance within a single training session remained intact, while improvement between training sessions was impaired. ANI injections did not affect infarct size. Thus, protein synthesis inhibition within the peri-infarct cortex impairs recovery of motor deficits after ischemic stroke by interfering with consolidation of motor memory between training sessions but not short-term improvements within one session.

Transforming growth factor β recruits persistent MAPK signaling to regulate long-term memory consolidation in Aplysia californica.

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Shobe, Justin; Philips, Gary T; Carew, Thomas J

2016-05-01

In this study, we explore the mechanistic relationship between growth factor signaling and kinase activity that supports the protein synthesis-dependent phase of long-term memory (LTM) consolidation for sensitization ofAplysia Specifically, we examine LTM for tail shock-induced sensitization of the tail-elicited siphon withdrawal (T-SW) reflex, a form of memory that requires both (i) extracellular signal-regulated kinase (ERK1/2; MAPK) activity within identified sensory neurons (SNs) that mediate the T-SW and (ii) the activation of transforming growth factor β (TGFβ) signaling. We now report that repeated tail shocks that induce intermediate-term (ITM) and LTM for sensitization, also induce a sustained post-training phase of MAPK activity in SNs (lasting at least 1 h). We identified two mechanistically distinct phases of post-training MAPK: (i) an immediate phase that does not require ongoing protein synthesis or TGFβ signaling, and (ii) a sustained phase that requires both protein synthesis and extracellular TGFβ signaling. We find that LTM consolidation requires sustained MAPK, and is disrupted by inhibitors of protein synthesis and TGFβ signaling during the consolidation window. These results provide strong evidence that TGFβ signaling sustains MAPK activity as an essential mechanistic step for LTM consolidation. © 2016 Shobe et al.; Published by Cold Spring Harbor Laboratory Press.

Protein kinase M ζ and the maintenance of long-term memory.

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Zhang, Yang; Zong, Wei; Zhang, Lei; Ma, Yuanye; Wang, Jianhong

2016-10-01

Although various molecules have been found to mediate the processes of memory acquisition and consolidation, the molecular mechanism to maintain memory still remains elusive. In recent years, a molecular pathway focusing on protein kinase Mζ (PKMζ) has become of interest to researchers because of its potential role in long-term memory maintenance. PKMζ is an isoform of protein kinase C (PKC) and has a related structure that influences its function in maintaining memory. Considerable evidence has been gathered on PKMζ activity, including loss of function studies using PKMζ inhibitors, such as PKMζ inhibitory peptide (ZIP), suggesting PKMζ plays an important role in long-term memory maintenance. This review provides an overview of the role of PKMζ in long-term memory and outlines the molecular structure of PKMζ, the molecular mechanism of PKMζ in long-term memory maintenance and future directions of PKMζ research. Copyright © 2016 Elsevier Ltd. All rights reserved.

Exchange Protein Activated by cAMP Enhances Long-Term Memory Formation Independent of Protein Kinase A

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Ma, Nan; Abel, Ted; Hernandez, Pepe J.

2009-01-01

It is well established that cAMP signaling within neurons plays a major role in the formation of long-term memories--signaling thought to proceed through protein kinase A (PKA). However, here we show that exchange protein activated by cAMP (Epac) is able to enhance the formation of long-term memory in the hippocampus and appears to do so…

Reconsolidation of a Context Long-Term Memory in the Terrestrial Snail Requires Protein Synthesis

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Gainutdinova, Tatiana H.; Tagirova, Rosa R.; Ismailova, Asja I.; Muranova, Lyudmila N.; Samarova, Elena I.; Gainutdinov, Khalil L.; Balaban, Pavel M.

2005-01-01

We investigated the influence of the protein synthesis blocker anisomycin on contextual memory in the terrestrial snail "Helix." Prior to the training session, the behavioral responses in two contexts were similar. Two days after a session of electric shocks (5 d) in one context only, the context conditioning was observed as the significant…

Overexpression of Protein Kinase Mζ in the Hippocampus Enhances Long-Term Potentiation and Long-Term Contextual But Not Cued Fear Memory in Rats.

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Schuette, Sven R M; Fernández-Fernández, Diego; Lamla, Thorsten; Rosenbrock, Holger; Hobson, Scott

2016-04-13

The persistently active protein kinase Mζ (PKMζ) has been found to be involved in the formation and maintenance of long-term memory. Most of the studies investigating PKMζ, however, have used either putatively unselective inhibitors or conventional knock-out animal models in which compensatory mechanisms may occur. Here, we overexpressed an active form of PKMζ in rat hippocampus, a structure highly involved in memory formation, and embedded in several neural networks. We investigated PKMζ's influence on synaptic plasticity using electrophysiological recordings of basal transmission, paired pulse facilitation, and LTP and combined this with behavioral cognitive experiments addressing formation and retention of both contextual memory during aversive conditioning and spatial memory during spontaneous exploration. We demonstrate that hippocampal slices overexpressing PKMζ show enhanced basal transmission, suggesting a potential role of PKMζ in postsynaptic AMPAR trafficking. Moreover, the PKMζ-overexpressing slices augmented LTP and this effect was not abolished by protein-synthesis blockers, indicating that PKMζ induces enhanced LTP formation in a protein-synthesis-independent manner. In addition, we found selectively enhanced long-term memory for contextual but not cued fear memory, underlining the theory of the hippocampus' involvement in the contextual aspect of aversive reinforced tasks. Memory for spatial orientation during spontaneous exploration remained unaltered, suggesting that PKMζ may not affect the neural circuits underlying spontaneous tasks that are different from aversive tasks. In this study, using an overexpression strategy as opposed to an inhibitor-based approach, we demonstrate an important modulatory role of PKMζ in synaptic plasticity and selective memory processing. Most of the literature investigating protein kinase Mζ (PKMζ) used inhibitors with selectivity that has been called into question or conventional knock-out animal

Persistent long-term facilitation at an identified synapse becomes labile with activation of short-term heterosynaptic plasticity.

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Hu, Jiang-Yuan; Schacher, Samuel

2014-04-02

Short-term and long-term synaptic plasticity are cellular correlates of learning and memory of different durations. Little is known, however, how these two forms of plasticity interact at the same synaptic connection. We examined the reciprocal impact of short-term heterosynaptic or homosynaptic plasticity at sensorimotor synapses of Aplysia in cell culture when expressing persistent long-term facilitation (P-LTF) evoked by serotonin [5-hydroxytryptamine (5-HT)]. Short-term heterosynaptic plasticity induced by 5-HT (facilitation) or the neuropeptide FMRFa (depression) and short-term homosynaptic plasticity induced by tetanus [post-tetanic potentiation (PTP)] or low-frequency stimulation [homosynaptic depression (HSD)] of the sensory neuron were expressed in both control synapses and synapses expressing P-LTF in the absence or presence of protein synthesis inhibitors. All forms of short-term plasticity failed to significantly affect ongoing P-LTF in the absence of protein synthesis inhibitors. However, P-LTF reversed to control levels when either 5-HT or FMRFa was applied in the presence of rapamycin. In contrast, P-LTF was unaffected when either PTP or HSD was evoked in the presence of either rapamycin or anisomycin. These results indicate that synapses expressing persistent plasticity acquire a "new" baseline and functionally express short-term changes as naive synapses, but the new baseline becomes labile following selective activations-heterosynaptic stimuli that evoke opposite forms of plasticity-such that when presented in the presence of protein synthesis inhibitors produce a rapid reversal of the persistent plasticity. Activity-selective induction of a labile state at synapses expressing persistent plasticity may facilitate the development of therapies for reversing inappropriate memories.

Testing for long-range dependence in the Brazilian term structure of interest rates

International Nuclear Information System (INIS)

Cajueiro, Daniel O.; Tabak, Benjamin M.

2009-01-01

This paper presents empirical evidence of fractional dynamics in interest rates for different maturities for Brazil. A variation of a newly developed test for long-range dependence, the V/S statistic, with a post-blackening bootstrap is employed. Results suggest that Brazilian interest rates possess strong long-range dependence in volatility, even when considering the structural break in 1999. These findings imply that the development of policy models that give rise to long-range dependence in interest rates' volatility could be very useful. The long-short-term interest rates spread has strong long-range dependence, which suggests that traditional tests of expectation hypothesis of the term structure of interest rates may be misspecified.

Time course of protein synthesis-dependent phase of olfactory memory in the cricket Gryllus bimaculatus.

Science.gov (United States)

Matsumoto, Yukihisa; Noji, Sumihare; Mizunami, Makoto

2003-04-01

The cricket Gryllus bimaculatus forms a stable olfactory memory that lasts for practically a lifetime. As a first step to elucidate the cellular mechanisms of olfactory learning and memory retention in crickets, we studied the dependency of memory retention on the de novo brain protein synthesis by injecting the protein synthesis inhibitor cycloheximide (CHX) into the head capsule. Injection of CHX inhibited (3)H-leucine incorporation into brain proteins by > 90% for 3 hr. Crickets were trained to associate peppermint odor with water (reward) and vanilla odor with saline solution (non-reward) and were injected with CHX before or at different times after training. Their odor preferences were tested at 2 hr, 1 day and 4 days after training. Memory retention at 2 hr after training was unaffected by CHX injection. However, the level of retention at 1 day and 4 days after training was lowered when CHX was injected 1 hour before training or at 1 hr or 6 hr after training. To study the time course of the development of CHX-sensitive memory phase, crickets that had been injected with CHX at 1 hr after training were tested at different times from 2 to 12 hr after training. The level of retention was unaffected up to 4 hr after training but significantly lowered at 5 hr after training, and the CHX-sensitive memory phase developed gradually during the next several hours. CHX dissociates two phases of olfactory memory in crickets: earlier protein synthesis-independent phase ( 5 hr) protein synthesis-dependent phase.

Methylphenidate during early consolidation affects long-term associative memory retrieval depending on baseline catecholamines.

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Wagner, Isabella C; van Buuren, Mariët; Bovy, Leonore; Morris, Richard G; Fernández, Guillén

2017-02-01

Synaptic memory consolidation is thought to rely on catecholaminergic signaling. Eventually, it is followed by systems consolidation, which embeds memories in a neocortical network. Although this sequence was demonstrated in rodents, it is unclear how catecholamines affect memory consolidation in humans. Here, we tested the effects of catecholaminergic modulation on synaptic and subsequent systems consolidation. We expected enhanced memory performance and increased neocortical engagement during delayed retrieval. Additionally, we tested if this effect was modulated by individual differences in a cognitive proxy measure of baseline catecholamine synthesis capacity. Fifty-three healthy males underwent a between-subjects, double-blind, placebo-controlled procedure across 2 days. On day 1, subjects studied and retrieved object-location associations and received 20 mg of methylphenidate or placebo. Drug intake was timed so that methylphenidate was expected to affect early consolidation but not encoding or retrieval. Memory was tested again while subjects were scanned three days later. Methylphenidate did not facilitate memory performance, and there was no significant group difference in activation during delayed retrieval. However, memory representations differed between groups depending on baseline catecholamines. The placebo group showed increased activation in occipito-temporal regions but decreased connectivity with the hippocampus, associated with lower baseline catecholamine synthesis capacity. The methylphenidate group showed stronger activation in the postcentral gyrus, associated with higher baseline catecholamine synthesis capacity. Altogether, methylphenidate during early consolidation did not foster long-term memory performance, but it affected retrieval-related neural processes depending on individual levels of baseline catecholamines.

Observation of long term potentiation in papain-based memory devices

KAUST Repository

Bag, A.; Hota, Mrinal Kanti; Mallik, Sandipan B.; Maì ti, Chinmay Kumar

2014-01-01

Biological synaptic behavior in terms of long term potentiation has been observed in papain-based (plant protein) memory devices (memristors) for the first time. Improvement in long term potentiation depends on pulse amplitude and width (duration). Continuous/repetitive dc voltage sweep leads to an increase in memristor conductivity leading to a long term memory in the 'learning' processes.

Observation of long term potentiation in papain-based memory devices

KAUST Repository

Bag, A.

2014-06-01

Biological synaptic behavior in terms of long term potentiation has been observed in papain-based (plant protein) memory devices (memristors) for the first time. Improvement in long term potentiation depends on pulse amplitude and width (duration). Continuous/repetitive dc voltage sweep leads to an increase in memristor conductivity leading to a long term memory in the \\'learning\\' processes.

Behavioral tagging is a general mechanism of long-term memory formation.

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Ballarini, Fabricio; Moncada, Diego; Martinez, Maria Cecilia; Alen, Nadia; Viola, Haydée

2009-08-25

In daily life, memories are intertwined events. Little is known about the mechanisms involved in their interactions. Using two hippocampus-dependent (spatial object recognition and contextual fear conditioning) and one hippocampus-independent (conditioned taste aversion) learning tasks, we show that in rats subjected to weak training protocols that induce solely short term memory (STM), long term memory (LTM) is promoted and formed only if training sessions took place in contingence with a novel, but not familiar, experience occurring during a critical time window around training. This process requires newly synthesized proteins induced by novelty and reveals a general mechanism of LTM formation that begins with the setting of a "learning tag" established by a weak training. These findings represent the first comprehensive set of evidences indicating the existence of a behavioral tagging process that in analogy to the synaptic tagging and capture process, need the creation of a transient, protein synthesis-independent, and input specific tag.

Amino acids augment muscle protein synthesis in neonatal pigs during acute endotoxemia by stimulating mTOR-dependent translation initiation.

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Orellana, Renán A; Jeyapalan, Asumthia; Escobar, Jeffery; Frank, Jason W; Nguyen, Hanh V; Suryawan, Agus; Davis, Teresa A

2007-11-01

In skeletal muscle of adults, sepsis reduces protein synthesis by depressing translation initiation and induces resistance to branched-chain amino acid stimulation. Normal neonates maintain a high basal muscle protein synthesis rate that is sensitive to amino acid stimulation. In the present study, we determined the effect of amino acids on protein synthesis in skeletal muscle and other tissues in septic neonates. Overnight-fasted neonatal pigs were infused with endotoxin (LPS, 0 and 10 microg.kg(-1).h(-1)), whereas glucose and insulin were maintained at fasting levels; amino acids were clamped at fasting or fed levels. In the presence of fasting insulin and amino acids, LPS reduced protein synthesis in longissimus dorsi (LD) and gastrocnemius muscles and increased protein synthesis in the diaphragm, but had no effect in masseter and heart muscles. Increasing amino acids to fed levels accelerated muscle protein synthesis in LD, gastrocnemius, masseter, and diaphragm. LPS stimulated protein synthesis in liver, lung, spleen, pancreas, and kidney in fasted animals. Raising amino acids to fed levels increased protein synthesis in liver of controls, but not LPS-treated animals. The increase in muscle protein synthesis in response to amino acids was associated with increased mTOR, 4E-BP1, and S6K1 phosphorylation and eIF4G-eIF4E association in control and LPS-infused animals. These findings suggest that amino acids stimulate skeletal muscle protein synthesis during acute endotoxemia via mTOR-dependent ribosomal assembly despite reduced basal protein synthesis rates in neonatal pigs. However, provision of amino acids does not further enhance the LPS-induced increase in liver protein synthesis.

Flavonoid fisetin promotes ERK-dependent long-term potentiation and enhances memory

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Maher, Pamela; Akaishi, Tatsuhiro; Abe, Kazuho

2006-01-01

Small molecules that activate signaling pathways used by neurotrophic factors could be useful for treating CNS disorders. Here we show that the flavonoid fisetin activates ERK and induces cAMP response element-binding protein (CREB) phosphorylation in rat hippocampal slices, facilitates long-term potentiation in rat hippocampal slices, and enhances object recognition in mice. Together, these data demonstrate that the natural product fisetin can facilitate long-term memory, and therefore it may be useful for treating patients with memory disorders. PMID:17050681

HDAC Inhibition Modulates Hippocampus-Dependent Long-Term Memory for Object Location in a CBP-Dependent Manner

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Haettig, Jakob; Stefanko, Daniel P.; Multani, Monica L.; Figueroa, Dario X.; McQuown, Susan C.; Wood, Marcelo A.

2011-01-01

Transcription of genes required for long-term memory not only involves transcription factors, but also enzymatic protein complexes that modify chromatin structure. Chromatin-modifying enzymes, such as the histone acetyltransferase (HAT) CREB (cyclic-AMP response element binding) binding protein (CBP), are pivotal for the transcriptional regulation…

Hippocampal long term memory: effect of the cholinergic system on local protein synthesis.

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Lana, Daniele; Cerbai, Francesca; Di Russo, Jacopo; Boscaro, Francesca; Giannetti, Ambra; Petkova-Kirova, Polina; Pugliese, Anna Maria; Giovannini, Maria Grazia

2013-11-01

The present study was aimed at establishing a link between the cholinergic system and the pathway of mTOR and its downstream effector p70S6K, likely actors in long term memory encoding. We performed in vivo behavioral experiments using the step down inhibitory avoidance test (IA) in adult Wistar rats to evaluate memory formation under different conditions, and immunohistochemistry on hippocampal slices to evaluate the level and the time-course of mTOR and p70S6K activation. We also examined the effect of RAPA, inhibitor of mTORC1 formation, and of the acetylcholine (ACh) muscarinic receptor antagonist scopolamine (SCOP) or ACh nicotinic receptor antagonist mecamylamine (MECA) on short and long term memory formation and on the functionality of the mTOR pathway. Acquisition test was performed 30 min after i.c.v. injection of RAPA, a time sufficient for the drug to diffuse to CA1 pyramidal neurons, as demonstrated by MALDI-TOF-TOF imaging. Recall test was performed 1 h, 4 h or 24 h after acquisition. To confirm our results we performed in vitro experiments on live hippocampal slices: we evaluated whether stimulation of the cholinergic system with the cholinergic receptor agonist carbachol (CCh) activated the mTOR pathway and whether the administration of the above-mentioned antagonists together with CCh could revert this activation. We found that (1) mTOR and p70S6K activation in the hippocampus were involved in long term memory formation; (2) RAPA administration caused inhibition of mTOR activation at 1 h and 4 h and of p70S6K activation at 4 h, and long term memory impairment at 24 h after acquisition; (3) scopolamine treatment caused short but not long term memory impairment with an early increase of mTOR/p70S6K activation at 1 h followed by stabilization at longer times; (4) mecamylamine plus scopolamine treatment caused short term memory impairment at 1 h and 4 h and reduced the scopolamine-induced increase of mTOR/p70S6K activation at 1 h and 4 h; (5

Roles of calcium/calmodulin-dependent kinase II in long-term memory formation in crickets.

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Makoto Mizunami

Full Text Available Ca(2+/calmodulin (CaM-dependent protein kinase II (CaMKII is a key molecule in many systems of learning and memory in vertebrates, but roles of CaMKII in invertebrates have not been characterized in detail. We have suggested that serial activation of NO/cGMP signaling, cyclic nucleotide-gated channel, Ca(2+/CaM and cAMP signaling participates in long-term memory (LTM formation in olfactory conditioning in crickets, and here we show participation of CaMKII in LTM formation and propose its site of action in the biochemical cascades. Crickets subjected to 3-trial conditioning to associate an odor with reward exhibited memory that lasts for a few days, which is characterized as protein synthesis-dependent LTM. In contrast, animals subjected to 1-trial conditioning exhibited memory that lasts for only several hours (mid-term memory, MTM. Injection of a CaMKII inhibitor prior to 3-trial conditioning impaired 1-day memory retention but not 1-hour memory retention, suggesting that CaMKII participates in LTM formation but not in MTM formation. Animals injected with a cGMP analogue, calcium ionophore or cAMP analogue prior to 1-trial conditioning exhibited 1-day retention, and co-injection of a CaMKII inhibitor impaired induction of LTM by the cGMP analogue or that by the calcium ionophore but not that by the cAMP analogue, suggesting that CaMKII is downstream of cGMP production and Ca(2+ influx and upstream of cAMP production in biochemical cascades for LTM formation. Animals injected with an adenylyl cyclase (AC activator prior to 1-trial conditioning exhibited 1-day retention. Interestingly, a CaMKII inhibitor impaired LTM induction by the AC activator, although AC is expected to be a downstream target of CaMKII. The results suggest that CaMKII interacts with AC to facilitate cAMP production for LTM formation. We propose that CaMKII serves as a key molecule for interplay between Ca(2+ signaling and cAMP signaling for LTM formation, a new role of Ca

Ribosome-dependent ATPase interacts with conserved membrane protein in Escherichia coli to modulate protein synthesis and oxidative phosphorylation.

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Mohan Babu

Full Text Available Elongation factor RbbA is required for ATP-dependent deacyl-tRNA release presumably after each peptide bond formation; however, there is no information about the cellular role. Proteomic analysis in Escherichia coli revealed that RbbA reciprocally co-purified with a conserved inner membrane protein of unknown function, YhjD. Both proteins are also physically associated with the 30S ribosome and with members of the lipopolysaccharide transport machinery. Genome-wide genetic screens of rbbA and yhjD deletion mutants revealed aggravating genetic interactions with mutants deficient in the electron transport chain. Cells lacking both rbbA and yhjD exhibited reduced cell division, respiration and global protein synthesis as well as increased sensitivity to antibiotics targeting the ETC and the accuracy of protein synthesis. Our results suggest that RbbA appears to function together with YhjD as part of a regulatory network that impacts bacterial oxidative phosphorylation and translation efficiency.

Regulation of very-long acyl chain ceramide synthesis by acyl-CoA-binding protein

DEFF Research Database (Denmark)

Ferreira, Natalia Santos; Engelsby, Hanne; Neess, Ditte

2017-01-01

and cardiovascular diseases, as well as neurological disorders. Here we show that acyl-coenzyme A-binding protein (ACBP) potently facilitates very-long acyl chain ceramide synthesis. ACBP increases the activity of ceramide synthase 2 (CerS2) by more than 2-fold and CerS3 activity by 7-fold. ACBP binds very......-long-chain acyl-CoA esters, which is required for its ability to stimulate CerS activity. We also show that high-speed liver cytosol from wild-type mice activates CerS3 activity, whereas cytosol from ACBP knock-out mice does not. Consistently, CerS2 and CerS3 activities are significantly reduced in the testes...... of ACBP(-/-) mice, concomitant with a significant reduction in long- and very-long-chain ceramide levels. Importantly, we show that ACBP interacts with CerS2 and CerS3. Our data uncover a novel mode of regulation of very-long acyl chain ceramide synthesis by ACBP, which we anticipate is of crucial...

Acute high-caffeine exposure increases autophagic flux and reduces protein synthesis in C2C12 skeletal myotubes.

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Hughes, M A; Downs, R M; Webb, G W; Crocker, C L; Kinsey, S T; Baumgarner, Bradley L

2017-04-01

Caffeine is a highly catabolic dietary stimulant. High caffeine concentrations (1-10 mM) have previously been shown to inhibit protein synthesis and increase protein degradation in various mammalian cell lines. The purpose of this study was to examine the effect of short-term caffeine exposure on cell signaling pathways that regulate protein metabolism in mammalian skeletal muscle cells. Fully differentiated C2C12 skeletal myotubes either received vehicle (DMSO) or 5 mM caffeine for 6 h. Our analysis revealed that caffeine promoted a 40% increase in autolysosome formation and a 25% increase in autophagic flux. In contrast, caffeine treatment did not significantly increase the expression of the skeletal muscle specific ubiquitin ligases MAFbx and MuRF1 or 20S proteasome activity. Caffeine treatment significantly reduced mTORC1 signaling, total protein synthesis and myotube diameter in a CaMKKβ/AMPK-dependent manner. Further, caffeine promoted a CaMKII-dependent increase in myostatin mRNA expression that did not significantly contribute to the caffeine-dependent reduction in protein synthesis. Our results indicate that short-term caffeine exposure significantly reduced skeletal myotube diameter by increasing autophagic flux and promoting a CaMKKβ/AMPK-dependent reduction in protein synthesis.

Spinal 5-HT7 Receptors and Protein Kinase A Constrain Intermittent Hypoxia-Induced Phrenic Long-term Facilitation

Science.gov (United States)

Hoffman, M.S.; Mitchell, G.S.

2013-01-01

Phrenic long-term facilitation (pLTF) is a form of serotonin-dependent respiratory plasticity induced by acute intermittent hypoxia (AIH). pLTF requires spinal Gq protein-coupled serotonin-2 receptor (5-HT2) activation, new synthesis of brain-derived neurotrophic factor (BDNF) and activation of its high-affinity receptor, TrkB. Intrathecal injections of selective agonists for Gs protein-coupled receptors (adenosine 2A and serotonin-7; 5-HT7) also induce long-lasting phrenic motor facilitation via TrkB “trans-activation.” Since serotonin release near phrenic motor neurons may activate multiple serotonin receptor subtypes, we tested the hypothesis that 5-HT7 receptor activation contributes to AIH-induced pLTF. A selective 5-HT7 receptor antagonist (SB-269970, 5mM, 12μl) was administered intrathecally at C4 to anesthetized, vagotomized and ventilated rats prior to AIH (3, 5-min episodes, 11% O2). Contrary to predictions, pLTF was greater in SB-269970 treated versus control rats (80±11% vs 45±6% 60 min post-AIH; p<0.05). Hypoglossal LTF was unaffected by spinal 5-HT7 receptor inhibition, suggesting that drug effects were localized to the spinal cord. Since 5-HT7 receptors are coupled to protein kinase A (PKA), we tested the hypothesis that PKA inhibits AIH-induced pLTF. Similar to 5-HT7 receptor inhibition, spinal PKA inhibition (KT-5720, 100μM, 15μl) enhanced pLTF (99±15% 60 min post-AIH; p<0.05). Conversely, PKA activation (8-br-cAMP, 100μM, 15μl) blunted pLTF versus control rats (16±5% vs 45±6% 60 min post-AIH; p<0.05). These findings suggest a novel mechanism whereby spinal Gs protein-coupled 5-HT7 receptors constrain AIH-induced pLTF via PKA activity. PMID:23850591

Mammalian target of rapamycin is required for phrenic long-term facilitation following severe but not moderate acute intermittent hypoxia.

Science.gov (United States)

Dougherty, Brendan J; Fields, Daryl P; Mitchell, Gordon S

2015-09-01

Phrenic long-term facilitation (pLTF) is a persistent increase in phrenic nerve activity after acute intermittent hypoxia (AIH). Distinct cell-signaling cascades give rise to pLTF depending on the severity of hypoxemia within hypoxic episodes. Moderate AIH (mAIH; three 5-min episodes, PaO2 ∼35-55 mmHG) elicits pLTF by a serotonin (5-HT)-dependent mechanism that requires new synthesis of brain-derived neurotrophic factor (BDNF), activation of its high-affinity receptor (TrkB), and ERK MAPK signaling. In contrast, severe AIH (sAIH; three 5-min episodes, PaO2 ∼25-30 mmHG) elicits pLTF by an adenosine-dependent mechanism that requires new TrkB synthesis and Akt signaling. Although both mechanisms require spinal protein synthesis, the newly synthesized proteins are distinct, as are the neurochemicals inducing plasticity (serotonin vs. adenosine). In many forms of neuroplasticity, new protein synthesis requires translational regulation via mammalian target of rapamycin (mTOR) signaling. Since Akt regulates mTOR activity, we hypothesized that mTOR activity is necessary for sAIH- but not mAIH-induced pLTF. Phrenic nerve activity in anesthetized, paralyzed, and ventilated rats was recorded before, during, and 60 min after mAIH or sAIH. Rats were pretreated with intrathecal injections of 20% DMSO (vehicle controls) or rapamycin (0.1 mM, 12 μl), a selective mTOR complex 1 inhibitor. Consistent with our hypothesis, rapamycin blocked sAIH- but not mAIH-induced pLTF. Thus spinal mTOR activity is required for adenosine-dependent (sAIH) but not serotonin-dependent (mAIH) pLTF, suggesting that distinct mechanisms regulate new protein synthesis in these forms of spinal neuroplasticity. Copyright © 2015 the American Physiological Society.

mTORC1-independent reduction of retinal protein synthesis in type 1 diabetes.

Science.gov (United States)

Fort, Patrice E; Losiewicz, Mandy K; Pennathur, Subramaniam; Jefferson, Leonard S; Kimball, Scot R; Abcouwer, Steven F; Gardner, Thomas W

2014-09-01

Poorly controlled diabetes has long been known as a catabolic disorder with profound loss of muscle and fat body mass resulting from a simultaneous reduction in protein synthesis and enhanced protein degradation. By contrast, retinal structure is largely maintained during diabetes despite reduced Akt activity and increased rate of cell death. Therefore, we hypothesized that retinal protein turnover is regulated differently than in other insulin-sensitive tissues, such as skeletal muscle. Ins2(Akita) diabetic mice and streptozotocin-induced diabetic rats exhibited marked reductions in retinal protein synthesis matched by a concomitant reduction in retinal protein degradation associated with preserved retinal mass and protein content. The reduction in protein synthesis depended on both hyperglycemia and insulin deficiency, but protein degradation was only reversed by normalization of hyperglycemia. The reduction in protein synthesis was associated with diminished protein translation efficiency but, surprisingly, not with reduced activity of the mTORC1/S6K1/4E-BP1 pathway. Instead, diabetes induced a specific reduction of mTORC2 complex activity. These findings reveal distinctive responses of diabetes-induced retinal protein turnover compared with muscle and liver that may provide a new means to ameliorate diabetic retinopathy. © 2014 by the American Diabetes Association. Readers may use this article as long as the work is properly cited, the use is educational and not for profit, and the work is not altered.

The requirement for enhanced CREB1 expression in consolidation of long-term synaptic facilitation and long-term excitability in sensory neurons of Aplysia

Science.gov (United States)

Liu, Rong-Yu; Cleary, Leonard J.; Byrne, John H.

2011-01-01

Accumulating evidence suggests that the transcriptional activator CREB1 is important for serotonin (5-HT)-induced long-term facilitation (LTF) of the sensorimotor synapse in Aplysia. Moreover, creb1 is among the genes activated by CREB1, suggesting a role for this protein beyond the induction phase of LTF. The time course of the requirement for CREB1 synthesis in the consolidation of long-term facilitation was examined using RNA interference (RNAi) techniques in sensorimotor co-cultures. Injection of CREB1 small-interfering RNA (siRNA) immediately or 10 h after 5-HT treatment blocked LTF when measured at 24 h and 48 h after treatment. In contrast, CREB1 siRNA did not block LTF when injected 16 h after 5-HT treatment. These results demonstrate that creb1 expression must be sustained for a relatively long time in order to support the consolidation of LTF. In addition, LTF is also accompanied by a long-term increase in the excitability (LTE) of sensory neurons (SNs). Because LTE was observed in the isolated SN after 5-HT treatment, this long-term change was intrinsic to that element of the circuit. LTE was blocked when CREB1 siRNA was injected into isolated SNs immediately after 5-HT treatment. These data suggest that 5-HT-induced CREB1 synthesis is required for consolidation of both LTF and LTE. PMID:21543617

A Presynaptic Role for FMRP during Protein Synthesis-Dependent Long-Term Plasticity in "Aplysia"

Science.gov (United States)

Till, Sally M.; Li, Hsiu-Ling; Miniaci, Maria Concetta; Kandel, Eric R.; Choi, Yun-Beom

2011-01-01

Loss of the Fragile X mental retardation protein (FMRP) is associated with presumed postsynaptic deficits in mouse models of Fragile X syndrome. However, the possible presynaptic roles of FMRP in learning-related plasticity have received little attention. As a result, the mechanisms whereby FMRP influences synaptic function remain poorly…

Stargazin regulates AMPA receptor trafficking through adaptor protein complexes during long-term depression

Science.gov (United States)

Matsuda, Shinji; Kakegawa, Wataru; Budisantoso, Timotheus; Nomura, Toshihiro; Kohda, Kazuhisa; Yuzaki, Michisuke

2013-11-01

Long-term depression (LTD) underlies learning and memory in various brain regions. Although postsynaptic AMPA receptor trafficking mediates LTD, its underlying molecular mechanisms remain largely unclear. Here we show that stargazin, a transmembrane AMPA receptor regulatory protein, forms a ternary complex with adaptor proteins AP-2 and AP-3A in hippocampal neurons, depending on its phosphorylation state. Inhibiting the stargazin-AP-2 interaction disrupts NMDA-induced AMPA receptor endocytosis, and inhibiting that of stargazin-AP-3A abrogates the late endosomal/lysosomal trafficking of AMPA receptors, thereby upregulating receptor recycling to the cell surface. Similarly, stargazin’s interaction with AP-2 or AP-3A is necessary for low-frequency stimulus-evoked LTD in CA1 hippocampal neurons. Thus, stargazin has a crucial role in NMDA-dependent LTD by regulating two trafficking pathways of AMPA receptors—transport from the cell surface to early endosomes and from early endosomes to late endosomes/lysosomes—through its sequential binding to AP-2 and AP-3A.

Oil use and oil dependency: Long-term issues

International Nuclear Information System (INIS)

Serot, D.E.; Belzer, D.B.; Guthrie, S.A.; Roop, J.M.

1989-06-01

The continued dependence of the United States on imported oil is a matter of increasing concern. Under the direction of the Department of Energy's Office of Policy Integration, Pacific Northwest Laboratory conducted a study which was to examine long-term issues related to oil dependence. Major issues addressed are (1) energy efficiency and the role of new technologies, (2) fuel switching, and (3) regional factors affecting fuel use. The study examines all major end-use sectors in the economy, covering the industrial, commercial, residential, transportation, and electric utility sectors. The potential impacts of efficiency improvements in oil- using equipment are assessed through the year 2000. 107 refs., 8 figs., 9 tabs

Protein Synthesis Underlies Post-Retrieval Memory Consolidation to a Restricted Degree Only when Updated Information Is Obtained

Science.gov (United States)

Rodriguez-Ortiz, Carlos J.; De la Cruz, Vanesa; Gutierrez, Ranier; Bermudez-Rattoni, Federico

2005-01-01

Consolidation theory proposes that through the synthesis of new proteins recently acquired memories are strengthened over time into a stable long-term memory trace. However, evidence has accumulated suggesting that retrieved memory is susceptible to disruption, seeming to consolidate again (reconsolidate) to be retained in long-term storage. Here…

Time-Dependent Global Sensitivity Analysis for Long-Term Degeneracy Model Using Polynomial Chaos

Directory of Open Access Journals (Sweden)

Jianbin Guo

2014-07-01

Full Text Available Global sensitivity is used to quantify the influence of uncertain model inputs on the output variability of static models in general. However, very few approaches can be applied for the sensitivity analysis of long-term degeneracy models, as far as time-dependent reliability is concerned. The reason is that the static sensitivity may not reflect the completed sensitivity during the entire life circle. This paper presents time-dependent global sensitivity analysis for long-term degeneracy models based on polynomial chaos expansion (PCE. Sobol’ indices are employed as the time-dependent global sensitivity since they provide accurate information on the selected uncertain inputs. In order to compute Sobol’ indices more efficiently, this paper proposes a moving least squares (MLS method to obtain the time-dependent PCE coefficients with acceptable simulation effort. Then Sobol’ indices can be calculated analytically as a postprocessing of the time-dependent PCE coefficients with almost no additional cost. A test case is used to show how to conduct the proposed method, then this approach is applied to an engineering case, and the time-dependent global sensitivity is obtained for the long-term degeneracy mechanism model.

Selective memory generalization by spatial patterning of protein synthesis.

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O'Donnell, Cian; Sejnowski, Terrence J

2014-04-16

Protein synthesis is crucial for both persistent synaptic plasticity and long-term memory. De novo protein expression can be restricted to specific neurons within a population, and to specific dendrites within a single neuron. Despite its ubiquity, the functional benefits of spatial protein regulation for learning are unknown. We used computational modeling to study this problem. We found that spatially patterned protein synthesis can enable selective consolidation of some memories but forgetting of others, even for simultaneous events that are represented by the same neural population. Key factors regulating selectivity include the functional clustering of synapses on dendrites, and the sparsity and overlap of neural activity patterns at the circuit level. Based on these findings, we proposed a two-step model for selective memory generalization during REM and slow-wave sleep. The pattern-matching framework we propose may be broadly applicable to spatial protein signaling throughout cortex and hippocampus. Copyright © 2014 Elsevier Inc. All rights reserved.

Roles of NO signaling in long-term memory formation in visual learning in an insect.

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Yukihisa Matsumoto

Full Text Available Many insects exhibit excellent capability of visual learning, but the molecular and neural mechanisms are poorly understood. This is in contrast to accumulation of information on molecular and neural mechanisms of olfactory learning in insects. In olfactory learning in insects, it has been shown that cyclic AMP (cAMP signaling critically participates in the formation of protein synthesis-dependent long-term memory (LTM and, in some insects, nitric oxide (NO-cyclic GMP (cGMP signaling also plays roles in LTM formation. In this study, we examined the possible contribution of NO-cGMP signaling and cAMP signaling to LTM formation in visual pattern learning in crickets. Crickets that had been subjected to 8-trial conditioning to associate a visual pattern with water reward exhibited memory retention 1 day after conditioning, whereas those subjected to 4-trial conditioning exhibited 30-min memory retention but not 1-day retention. Injection of cycloheximide, a protein synthesis inhibitor, into the hemolymph prior to 8-trial conditioning blocked formation of 1-day memory, whereas it had no effect on 30-min memory formation, indicating that 1-day memory can be characterized as protein synthesis-dependent long-term memory (LTM. Injection of an inhibitor of the enzyme producing an NO or cAMP prior to 8-trial visual conditioning blocked LTM formation, whereas it had no effect on 30-min memory formation. Moreover, injection of an NO donor, cGMP analogue or cAMP analogue prior to 4-trial conditioning induced LTM. Induction of LTM by an NO donor was blocked by DDA, an inhibitor of adenylyl cyclase, an enzyme producing cAMP, but LTM induction by a cAMP analogue was not impaired by L-NAME, an inhibitor of NO synthase. The results indicate that cAMP signaling is downstream of NO signaling for visual LTM formation. We conclude that visual learning and olfactory learning share common biochemical cascades for LTM formation.

Long-Term Condition Self-Management Support in Online Communities: A Meta-Synthesis of Qualitative Papers

Science.gov (United States)

Vassilev, Ivaylo; Kennedy, Anne; Rogers, Anne

2016-01-01

Background Recent years have seen an exponential increase in people with long-term conditions using the Internet for information and support. Prior research has examined support for long-term condition self-management through the provision of illness, everyday, and emotional work in the context of traditional offline communities. However, less is known about how communities hosted in digital spaces contribute through the creation of social ties and the mobilization of an online illness “workforce.” Objective The aim was to understand the negotiation of long-term condition illness work in patient online communities and how such work may assist the self-management of long-term conditions in daily life. Methods A systematic search of qualitative papers was undertaken using various online databases for articles published since 2004. A total of 21 papers met the inclusion criteria of using qualitative methods and examined the use of peer-led online communities for those with a long-term condition. A qualitative meta-synthesis was undertaken and the review followed a line of argument synthesis. Results The main themes identified in relation to the negotiation of self-management support were (1) redressing offline experiential information and knowledge deficits, (2) the influence of modeling and learning behaviors from others on self-management, (3) engagement that validates illness and negates offline frustrations, (4) tie formation and community building, (5) narrative expression and cathartic release, and (6) dissociative anonymity and invisibility. These translated into a line of argument synthesis in which four network mechanisms for self-management support in patient online communities were identified. These were (1) collective knowledge and identification through lived experience; (2) support, information, and engagement through readily accessible gifting relationships; (3) sociability that extends beyond illness; and (4) online disinhibition as a facilitator

Metabotropic glutamate receptor I (mGluR1) antagonism impairs cocaine-induced conditioned place preference via inhibition of protein synthesis.

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Yu, Fei; Zhong, Peng; Liu, Xiaojie; Sun, Dalong; Gao, Hai-Qing; Liu, Qing-Song

2013-06-01

Antagonism of group I metabotropic glutamate receptors (mGluR1 and mGluR5) reduces behavioral effects of drugs of abuse, including cocaine. However, the underlying mechanisms remain poorly understood. Activation of mGluR5 increases protein synthesis at synapses. Although mGluR5-induced excessive protein synthesis has been implicated in the pathology of fragile X syndrome, it remains unknown whether group I mGluR-mediated protein synthesis is involved in any behavioral effects of drugs of abuse. We report that group I mGluR agonist DHPG induced more pronounced initial depression of inhibitory postsynaptic currents (IPSCs) followed by modest long-term depression (I-LTD) in dopamine neurons of rat ventral tegmental area (VTA) through the activation of mGluR1. The early component of DHPG-induced depression of IPSCs was mediated by the cannabinoid CB1 receptors, while DHPG-induced I-LTD was dependent on protein synthesis. Western blotting analysis indicates that mGluR1 was coupled to extracellular signal-regulated kinase (ERK) and mammalian target of rapamycin (mTOR) signaling pathways to increase translation. We also show that cocaine conditioning activated translation machinery in the VTA via an mGluR1-dependent mechanism. Furthermore, intra-VTA microinjections of mGluR1 antagonist JNJ16259685 and protein synthesis inhibitor cycloheximide significantly attenuated or blocked the acquisition of cocaine-induced conditioned place preference (CPP) and activation of translation elongation factors. Taken together, these results suggest that mGluR1 antagonism inhibits de novo protein synthesis; this effect may block the formation of cocaine-cue associations and thus provide a mechanism for the reduction in CPP to cocaine.

Nuclear protein phosphatase-1: an epigenetic regulator of fear memory and amygdala long-term potentiation.

Science.gov (United States)

Koshibu, K; Gräff, J; Mansuy, I M

2011-01-26

Complex brain diseases and neurological disorders in human generally result from the disturbance of multiple genes and signaling pathways. These disturbances may derive from mutations, deletions, translocations or rearrangements of specific gene(s). However, over the past years, it has become clear that such disturbances may also derive from alterations in the epigenome affecting several genes simultaneously. Our work recently demonstrated that epigenetic mechanisms in the adult brain are in part regulated by protein phosphatase 1 (PP1), a protein Ser/Thr phosphatase that negatively regulates hippocampus-dependent long-term memory (LTM) and synaptic plasticity. PP1 is abundant in brain structures involved in emotional processing like the amygdala, it may therefore be involved in the regulation of fear memory, a form of memory related to post-traumatic stress disorder (PTSD) in human. Here, we demonstrate that PP1 is a molecular suppressor of fear memory and synaptic plasticity in the amygdala that can control chromatin remodeling in neurons. We show that the selective inhibition of the nuclear pool of PP1 in amygdala neurons significantly alters posttranslational modifications (PTMs) of histones and the expression of several memory-associated genes. These alterations correlate with enhanced fear memory, and with an increase in long-term potentiation (LTP) that is transcription-dependent. Our results underscore the importance of nuclear PP1 in the amygdala as an epigenetic regulator of emotional memory, and the relevance of protein phosphatases as potential targets for therapeutic treatment of brain disorders like PTSD. © 2011 IBRO. Published by Elsevier Ltd. All rights reserved.

Inhibition of protein synthesis but not β-adrenergic receptors blocks reconsolidation of a cocaine-associated cue memory.

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Dunbar, Amber B; Taylor, Jane R

2016-08-01

Previously consolidated memories have the potential to enter a state of lability upon memory recall, during which time the memory can be altered before undergoing an additional consolidation-like process and being stored again as a long-term memory. Blocking reconsolidation of aberrant memories has been proposed as a potential treatment for psychiatric disorders including addiction. Here we investigated of the effect of systemically administering the protein synthesis inhibitor cycloheximide or the β-adrenergic antagonist propranolol on reconsolidation. Rats were trained to self-administer cocaine, during which each lever press resulted in the presentation of a cue paired with an intravenous infusion of cocaine. After undergoing lever press extinction to reduce operant responding, the cue memory was reactivated and rats were administered systemic injections of propranolol, cycloheximide, or vehicle. Post-reactivation cycloheximide, but not propranolol, resulted in a reactivation-dependent decrease in cue-induced reinstatement, indicative of reconsolidation blockade by protein synthesis inhibition. The present data indicate that systemically targeting protein synthesis as opposed to the β-adrenergic system may more effectively attenuate the reconsolidation of a drug-related memory and decrease drug-seeking behavior. © 2016 Dunbar and Taylor; Published by Cold Spring Harbor Laboratory Press.

MicroRNA-22 Gates Long-Term Heterosynaptic Plasticity in Aplysia through Presynaptic Regulation of CPEB and Downstream Targets

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Ferdinando Fiumara

2015-06-01

Full Text Available The maintenance phase of memory-related long-term facilitation (LTF of synapses between sensory and motor neurons of the gill-withdrawal reflex of Aplysia depends on a serotonin (5-HT-triggered presynaptic upregulation of CPEB, a functional prion that regulates local protein synthesis at the synapse. The mechanisms whereby serotonin regulates CPEB levels in presynaptic sensory neurons are not known. Here, we describe a sensory neuron-specific microRNA 22 (miR-22 that has multiple binding sites on the mRNA of CPEB and inhibits it in the basal state. Serotonin triggers MAPK/Erk-dependent downregulation of miR-22, thereby upregulating the expression of CPEB, which in turn regulates, through functional CPE elements, the presynaptic expression of atypical PKC (aPKC, another candidate regulator of memory maintenance. Our findings support a model in which the neurotransmitter-triggered downregulation of miR-22 coordinates the regulation of genes contributing synergistically to the long-term maintenance of memory-related synaptic plasticity.

Verbal Short-Term Memory Span in Children: Long-Term Modality Dependent Effects of Intrauterine Growth Restriction

Science.gov (United States)

Geva, R.; Eshel, R.; Leitner, Y.; Fattal-Valevski, A.; Harel, S.

2008-01-01

Background: Recent reports showed that children born with intrauterine growth restriction (IUGR) are at greater risk of experiencing verbal short-term memory span (STM) deficits that may impede their learning capacities at school. It is still unknown whether these deficits are modality dependent. Methods: This long-term, prospective design study…

Activation of the CREB/c-Fos Pathway during Long-Term Synaptic Plasticity in the Cerebellum Granular Layer

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Daniela Gandolfi

2017-06-01

Full Text Available The induction of long-term potentiation and depression (LTP and LTD is thought to trigger gene expression and protein synthesis, leading to consolidation of synaptic and neuronal changes. However, while LTP and LTD have been proposed to play important roles for sensori-motor learning in the cerebellum granular layer, their association with these mechanisms remained unclear. Here, we have investigated phosphorylation of the cAMP-responsive element binding protein (CREB and activation of the immediate early gene c-Fos pathway following the induction of synaptic plasticity by theta-burst stimulation (TBS in acute cerebellar slices. LTP and LTD were localized using voltage-sensitive dye imaging (VSDi. At two time points following TBS (15 min and 120 min, corresponding to the early and late phases of plasticity, slices were fixed and processed to evaluate CREB phosphorylation (P-CREB and c-FOS protein levels, as well as Creb and c-Fos mRNA expression. High levels of P-CREB and Creb/c-Fos were detected before those of c-FOS, as expected if CREB phosphorylation triggered gene expression followed by protein synthesis. No differences between control slices and slices stimulated with TBS were observed in the presence of an N-methyl-D-aspartate receptor (NMDAR antagonist. Interestingly, activation of the CREB/c-Fos system showed a relevant degree of colocalization with long-term synaptic plasticity. These results show that NMDAR-dependent plasticity at the cerebellum input stage bears about transcriptional and post-transcriptional processes potentially contributing to cerebellar learning and memory consolidation.

Protein synthesis controls phosphate homeostasis.

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Pontes, Mauricio H; Groisman, Eduardo A

2018-01-01

Phosphorus is an essential element assimilated largely as orthophosphate (Pi). Cells respond to Pi starvation by importing Pi from their surroundings. We now report that impaired protein synthesis alone triggers a Pi starvation response even when Pi is plentiful in the extracellular milieu. In the bacterium Salmonella enterica serovar Typhimurium , this response entails phosphorylation of the regulatory protein PhoB and transcription of PhoB-dependent Pi transporter genes and is eliminated upon stimulation of adenosine triphosphate (ATP) hydrolysis. When protein synthesis is impaired due to low cytoplasmic magnesium (Mg 2+ ), Salmonella triggers the Pi starvation response because ribosomes are destabilized, which reduces ATP consumption and thus free cytoplasmic Pi. This response is transient because low cytoplasmic Mg 2+ promotes an uptake in Mg 2+ and a decrease in ATP levels, which stabilizes ribosomes, resulting in ATP consumption and Pi increase, thus ending the response. Notably, pharmacological inhibition of protein synthesis also elicited a Pi starvation response in the bacterium Escherichia coli and the yeast Saccharomyces cerevisiae Our findings identify a regulatory connection between protein synthesis and Pi homeostasis that is widespread in nature. © 2018 Pontes and Groisman; Published by Cold Spring Harbor Laboratory Press.

Autoradiographic study of protein synthesis recovery in root cells of Zea mays embryos during early stages of germination

International Nuclear Information System (INIS)

Deltour, Roger

1977-01-01

Recovery of protein synthesis was studied in primary root of germinating Zea mays embryos. [H 3 ] leucine or [H 3 ] lysine was provided for two hours at 16 0 C to embryos excised from kernels at various times after the beginning of germination. Protein synthesis (probably dependent on long-lived mRNA stocked in dormant embryo root cells) resumed during the first two hours of seed imbibition [fr

Autoradiographic study of protein synthesis recovery in root cells of Zea mays embryos during early stages of germination

Energy Technology Data Exchange (ETDEWEB)

Deltour, R [Liege Univ. (Belgium)

1977-05-02

Recovery of protein synthesis was studied in primary root of germinating Zea mays embryos. (H/sup 3/) leucine or (H/sup 3/) lysine was provided for two hours at 16/sup 0/C to embryos excised from kernels at various times after the beginning of germination. Protein synthesis (probably dependent on long-lived mRNA stocked in dormant embryo root cells) resumed during the first two hours of seed imbibition.

Fragile X Mental Retardation Protein Is Required to Maintain Visual Conditioning-Induced Behavioral Plasticity by Limiting Local Protein Synthesis.

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Liu, Han-Hsuan; Cline, Hollis T

2016-07-06

Fragile X mental retardation protein (FMRP) is thought to regulate neuronal plasticity by limiting dendritic protein synthesis, but direct demonstration of a requirement for FMRP control of local protein synthesis during behavioral plasticity is lacking. Here we tested whether FMRP knockdown in Xenopus optic tectum affects local protein synthesis in vivo and whether FMRP knockdown affects protein synthesis-dependent visual avoidance behavioral plasticity. We tagged newly synthesized proteins by incorporation of the noncanonical amino acid azidohomoalanine and visualized them with fluorescent noncanonical amino acid tagging (FUNCAT). Visual conditioning and FMRP knockdown produce similar increases in FUNCAT in tectal neuropil. Induction of visual conditioning-dependent behavioral plasticity occurs normally in FMRP knockdown animals, but plasticity degrades over 24 h. These results indicate that FMRP affects visual conditioning-induced local protein synthesis and is required to maintain the visual conditioning-induced behavioral plasticity. Fragile X syndrome (FXS) is the most common form of inherited intellectual disability. Exaggerated dendritic protein synthesis resulting from loss of fragile X mental retardation protein (FMRP) is thought to underlie cognitive deficits in FXS, but no direct evidence has demonstrated that FMRP-regulated dendritic protein synthesis affects behavioral plasticity in intact animals. Xenopus tadpoles exhibit a visual avoidance behavior that improves with visual conditioning in a protein synthesis-dependent manner. We showed that FMRP knockdown and visual conditioning dramatically increase protein synthesis in neuronal processes. Furthermore, induction of visual conditioning-dependent behavioral plasticity occurs normally after FMRP knockdown, but performance rapidly deteriorated in the absence of FMRP. These studies show that FMRP negatively regulates local protein synthesis and is required to maintain visual conditioning

Verbal short-term memory span in children: long-term modality dependent effects of intrauterine growth restriction.

Science.gov (United States)

Geva, R; Eshel, R; Leitner, Y; Fattal-Valevski, A; Harel, S

2008-12-01

Recent reports showed that children born with intrauterine growth restriction (IUGR) are at greater risk of experiencing verbal short-term memory span (STM) deficits that may impede their learning capacities at school. It is still unknown whether these deficits are modality dependent. This long-term, prospective design study examined modality-dependent verbal STM functions in children who were diagnosed at birth with IUGR (n = 138) and a control group (n = 64). Their STM skills were evaluated individually at 9 years of age with four conditions of the Visual-Aural Digit Span Test (VADS; Koppitz, 1981): auditory-oral, auditory-written, visuospatial-oral and visuospatial-written. Cognitive competence was evaluated with the short form of the Wechsler Intelligence Scales for Children--revised (WISC-R95; Wechsler, 1998). We found IUGR-related specific auditory-oral STM deficits (p long-term relationship between prenatal aberrant head growth and auditory verbal STM deficits by the end of the first decade of life. Empirical, clinical and educational implications are presented.

Sex- and histamine-dependent long-term cognitive effects of methamphetamine exposure

NARCIS (Netherlands)

Acevedo, S.F.; de Esch, I.J.P.; Raber, J.

2007-01-01

As prenatal methamphetamine (MA) exposure results in long-term hippocampus-dependent cognitive deficits, the increased MA use in women of childbearing age is of great concern. As mice are most commonly used in genetic models, we started to study the potential effects of neonatal MA exposure in

Long-Term Effects of High-Protein Diets on Renal Function

DEFF Research Database (Denmark)

Kamper, Anne-Lise; Strandgaard, Svend

2017-01-01

progression and even cause CKD in healthy people. The protein source may be important. Daily red meat consumption over years may increase CKD risk, whereas white meat and dairy proteins appear to have no such effect, and fruit and vegetable proteins may be renal protective. Few randomized trials exist......Chronic kidney disease (CKD) has a prevalence of approximately 13% and is most frequently caused by diabetes and hypertension. In population studies, CKD etiology is often uncertain. Some experimental and observational human studies have suggested that high-protein intake may increase CKD...... with an observation time greater than 6 months, and most of these were conducted in patients with preexisting diseases that dispose to CKD. Results conflict and do not allow any conclusion about kidney-damaging effects of long-term, high-protein intake. Until additional data become available, present knowledge seems...

Optimizing the measurement of mitochondrial protein synthesis in human skeletal muscle.

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Burd, Nicholas A; Tardif, Nicolas; Rooyackers, Olav; van Loon, Luc J C

2015-01-01

The measurement of mitochondrial protein synthesis after food ingestion, contractile activity, and/or disease is often used to provide insight into skeletal muscle adaptations that occur in the longer term. Studies have shown that protein ingestion stimulates mitochondrial protein synthesis in human skeletal muscle. Minor differences in the stimulation of mitochondrial protein synthesis occur after a single bout of resistance or endurance exercise. There appear to be no measurable differences in mitochondrial protein synthesis between critically ill patients and aged-matched controls. However, the mitochondrial protein synthetic response is reduced at a more advanced age. In this paper, we discuss the challenges involved in the measurement of human skeletal muscle mitochondrial protein synthesis rates based on stable isotope amino acid tracer methods. Practical guidelines are discussed to improve the reliability of the measurement of mitochondrial protein synthesis rates. The value of the measurement of mitochondrial protein synthesis after a single meal or exercise bout on the prediction of the longer term skeletal muscle mass and performance outcomes in both the healthy and disease populations requires more work, but we emphasize that the measurements need to be reliable to be of any value to the field.

A kinase-dependent feedforward loop affects CREBB stability and long term memory formation.

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Lee, Pei-Tseng; Lin, Guang; Lin, Wen-Wen; Diao, Fengqiu; White, Benjamin H; Bellen, Hugo J

2018-02-23

In Drosophila , long-term memory (LTM) requires the cAMP-dependent transcription factor CREBB, expressed in the mushroom bodies (MB) and phosphorylated by PKA. To identify other kinases required for memory formation, we integrated Trojan exons encoding T2A-GAL4 into genes encoding putative kinases and selected for genes expressed in MB. These lines were screened for learning/memory deficits using UAS-RNAi knockdown based on an olfactory aversive conditioning assay. We identified a novel, conserved kinase, Meng-Po ( MP , CG11221 , SBK1 in human), the loss of which severely affects 3 hr memory and 24 hr LTM, but not learning. Remarkably, memory is lost upon removal of the MP protein in adult MB but restored upon its reintroduction. Overexpression of MP in MB significantly increases LTM in wild-type flies showing that MP is a limiting factor for LTM. We show that PKA phosphorylates MP and that both proteins synergize in a feedforward loop to control CREBB levels and LTM. key words: Drosophila, Mushroom bodies, SBK1, deGradFP, T2A-GAL4, MiMIC.

Protein mediated synthesis of fluorescent Au-nanoclusters for metal sensory coatings

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Vogel, Manja; Raff, Johannes [Helmholtz-Zentrum Dresden-Rossendorf e.V., Dresden (Germany). Biogeochemistry

2017-06-01

Fluorescent Au-nanocluster were successfully synthesized and used for the selective detection of Cu{sup 2} {sup +}. The synthesized Au-BSA-nanoclusters remain functional also after immobilization and show high thermal stability. Additionally, the transfer of the protein mediated Au-nanocluster synthesis route to S-layer proteins was achieved. (The presented work is part of the project BIONEWS dealing with long-term stable cells for the set-up and regeneration of sensor and actor materials for strategic relevant metals, in particular rare earth elements).

Cell growth and protein synthesis of unicellular green alga Chlamydomonas in heavy water

International Nuclear Information System (INIS)

Ishida, M.R.

1983-01-01

The effects of heavy water on the cell growth and protein synthesis of the photoautotrophically growing Chlamydomonas cells were studied. The growth rate of the cells is inversely proportional to the concentrations of heavy water. The cells can barely live in 90% heavy water, but they die in 99.85% heavy water within a few days. Incorporation of 14 Cleucine into cells is markedly stimulated by heavy water of various concentrations between 30 and 99.85% in the case of the short time incubation. Contrary to this, in the long time incubation as several days, heavy water inhibits the protein synthesis. Such two modes of the protein synthetic activities are dependent upon the incubation time of the cells grown photoautotrophically in the heavy water media. (author)

Learning-dependent neurogenesis in the olfactory bulb determines long-term olfactory memory.

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Sultan, S; Mandairon, N; Kermen, F; Garcia, S; Sacquet, J; Didier, A

2010-07-01

Inhibitory interneurons of the olfactory bulb are subjected to permanent adult neurogenesis. Their number is modulated by learning, suggesting that they could play a role in plastic changes of the bulbar network associated with olfactory memory. Adult male C57BL/6 mice were trained in an associative olfactory task, and we analyzed long-term retention of the task 5, 30, and 90 d post-training. In parallel, we assessed the fate of these newborn cells, mapped their distribution in the olfactory bulb and measured their functional implication using the immediate early gene Zif268. In a second set of experiments, we pharmacologically modulated glutamatergic transmission and using the same behavioral task assessed the consequences on memory retention and neurogenesis. Finally, by local infusion of an antimitotic drug, we selectively blocked neurogenesis during acquisition of the task and looked at the effects on memory retention. First we demonstrated that retrieval of an associative olfactory task recruits the newborn neurons in odor-specific areas of the olfactory bulb selected to survive during acquisition of the task and that it does this in a manner that depends on the strength of learning. We then demonstrated that acquisition is not dependent on neurogenesis if long-term retention of the task is abolished by blocking neurogenesis. Adult-born neurons are thus involved in changes in the neural representation of an odor; this underlies long-term olfactory memory as the strength of learning is linked to the duration of this memory. Neurogenesis thus plays a crucial role in long-term olfactory memory.

Cognitive effects of pregabalin in the treatment of long-term benzodiazepine-use and dependence.

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Oulis, Panagiotis; Kalogerakou, Stamatina; Anyfandi, Eleni; Konstantakopoulos, George; Papakosta, Vassiliki-Maria; Masdrakis, Vasilios; Tsaltas, Eleftheria

2014-05-01

Long-term benzodiazepine (BDZ) use and dependence affect cognitive functioning adversely and partly irreversibly. Emerging evidence suggests that pregabalin (PGB) might be a safe and efficacious treatment of long-term BDZ use. The aim of the present study was to investigate the changes in several core cognitive functions after successful treatment of long-term BDZ use and dependence with PGB. Fourteen patients with long-term BDZ use (mean duration >15 years) underwent neuropsychological assessment with the mini-mental state examination and four tests from the Cambridge Neuropsychological Test Automated Battery (CANTAB) battery before the initiation of PGB treatment and at a two months follow-up after the cessation of BDZs. Patients' CANTAB percentile score distributions were compared with normative CANTAB data. Patients improved on cognitive measures of global cognitive functioning, time orientation, psychomotor speed, and visuospatial memory and learning with strong effect sizes. By contrast, they failed to improve on measures of attentional flexibility. Despite their significant improvement, patients' scores on most tests remained still at the lower percentiles of CANTAB normative scores. Although preliminary, our findings suggest that successful treatment of long-term BDZ use with PGB is associated with a substantial, though only partial, recovery of BDZ-compromised neuropsychological functioning, at least at a 2-month follow-up. Copyright © 2014 John Wiley & Sons, Ltd.

Long-term habituation of the gill-withdrawal reflex in Aplysia requires gene transcription, calcineurin and L-type voltage-gated calcium channels

Directory of Open Access Journals (Sweden)

Joseph eEsdin

2010-11-01

Full Text Available Although habituation is possibly the simplest form of learning, we still do not fully understand the neurobiological basis of habituation in any organism. To advance the goal of a comprehensive understanding of habituation, we have studied long-term habituation (LTH of the gill-withdrawal reflex (GWR in the marine snail Aplysia californica. Previously, we showed that habituation of the GWR in a reduced preparation lasts for up to 12 hr, and depends on protein synthesis, as well as activation of protein phosphatases 1 and 2A and postsynaptic glutamate receptors. Here, we have used the reduced preparation to further analyze the mechanisms of LTH in Aplysia. We found that LTH of the GWR depends on RNA synthesis because it was blocked by both the irreversible transcriptional inhibitor actinomycin-D and the reversible transcriptional inhibitor, 5,6-dichlorobenzimidazole riboside (DRB. In addition, LTH requires activation of protein phosphatase 2B (calcineurin, because it was disrupted by ascomycin. Finally, LTH was blocked by nitrendipine, which indicates that activation of L-type voltage-gated Ca2+ channels is required for this form of learning. Together with our previous results, the present results indicate that exclusively presynaptic mechanisms, although possibly sufficient for short-term habituation, are insufficient for LTH. Rather, LTH must involve postsynaptic, as well as presynaptic, mechanisms.

Long-term memory consolidation: The role of RNA-binding proteins with prion-like domains.

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Sudhakaran, Indulekha P; Ramaswami, Mani

2017-05-04

Long-term and short-term memories differ primarily in the duration of their retention. At a molecular level, long-term memory (LTM) is distinguished from short-term memory (STM) by its requirement for new gene expression. In addition to transcription (nuclear gene expression) the translation of stored mRNAs is necessary for LTM formation. The mechanisms and functions for temporal and spatial regulation of mRNAs required for LTM is a major contemporary problem, of interest from molecular, cell biological, neurobiological and clinical perspectives. This review discusses primary evidence in support for translational regulatory events involved in LTM and a model in which different phases of translation underlie distinct phases of consolidation of memories. However, it focuses largely on mechanisms of memory persistence and the role of prion-like domains in this defining aspect of long-term memory. We consider primary evidence for the concept that Cytoplasmic Polyadenylation Element Binding (CPEB) protein enables the persistence of formed memories by transforming in prion-like manner from a soluble monomeric state to a self-perpetuating and persistent polymeric translationally active state required for maintaining persistent synaptic plasticity. We further discuss prion-like domains prevalent on several other RNA-binding proteins involved in neuronal translational control underlying LTM. Growing evidence indicates that such RNA regulatory proteins are components of mRNP (RiboNucleoProtein) granules. In these proteins, prion-like domains, being intrinsically disordered, could mediate weak transient interactions that allow the assembly of RNP granules, a source of silenced mRNAs whose translation is necessary for LTM. We consider the structural bases for RNA granules formation as well as functions of disordered domains and discuss how these complicate the interpretation of existing experimental data relevant to general mechanisms by which prion-domain containing RBPs

Protein remote homology detection based on bidirectional long short-term memory.

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Li, Shumin; Chen, Junjie; Liu, Bin

2017-10-10

Protein remote homology detection plays a vital role in studies of protein structures and functions. Almost all of the traditional machine leaning methods require fixed length features to represent the protein sequences. However, it is never an easy task to extract the discriminative features with limited knowledge of proteins. On the other hand, deep learning technique has demonstrated its advantage in automatically learning representations. It is worthwhile to explore the applications of deep learning techniques to the protein remote homology detection. In this study, we employ the Bidirectional Long Short-Term Memory (BLSTM) to learn effective features from pseudo proteins, also propose a predictor called ProDec-BLSTM: it includes input layer, bidirectional LSTM, time distributed dense layer and output layer. This neural network can automatically extract the discriminative features by using bidirectional LSTM and the time distributed dense layer. Experimental results on a widely-used benchmark dataset show that ProDec-BLSTM outperforms other related methods in terms of both the mean ROC and mean ROC50 scores. This promising result shows that ProDec-BLSTM is a useful tool for protein remote homology detection. Furthermore, the hidden patterns learnt by ProDec-BLSTM can be interpreted and visualized, and therefore, additional useful information can be obtained.

MicroRNA-22 Gates Long-Term Heterosynaptic Plasticity in Aplysia through Presynaptic Regulation of CPEB and Downstream Targets.

Science.gov (United States)

Fiumara, Ferdinando; Rajasethupathy, Priyamvada; Antonov, Igor; Kosmidis, Stylianos; Sossin, Wayne S; Kandel, Eric R

2015-06-30

The maintenance phase of memory-related long-term facilitation (LTF) of synapses between sensory and motor neurons of the gill-withdrawal reflex of Aplysia depends on a serotonin (5-HT)-triggered presynaptic upregulation of CPEB, a functional prion that regulates local protein synthesis at the synapse. The mechanisms whereby serotonin regulates CPEB levels in presynaptic sensory neurons are not known. Here, we describe a sensory neuron-specific microRNA 22 (miR-22) that has multiple binding sites on the mRNA of CPEB and inhibits it in the basal state. Serotonin triggers MAPK/Erk-dependent downregulation of miR-22, thereby upregulating the expression of CPEB, which in turn regulates, through functional CPE elements, the presynaptic expression of atypical PKC (aPKC), another candidate regulator of memory maintenance. Our findings support a model in which the neurotransmitter-triggered downregulation of miR-22 coordinates the regulation of genes contributing synergistically to the long-term maintenance of memory-related synaptic plasticity. Copyright © 2015 The Authors. Published by Elsevier Inc. All rights reserved.

Phrenic motor neuron TrkB expression is necessary for acute intermittent hypoxia-induced phrenic long-term facilitation.

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Dale, Erica A; Fields, Daryl P; Devinney, Michael J; Mitchell, Gordon S

2017-01-01

Phrenic long-term facilitation (pLTF) is a form of hypoxia-induced spinal respiratory motor plasticity that requires new synthesis of brain derived neurotrophic factor (BDNF) and activation of its high-affinity receptor, tropomyosin receptor kinase B (TrkB). Since the cellular location of relevant TrkB receptors is not known, we utilized intrapleural siRNA injections to selectively knock down TrkB receptor protein within phrenic motor neurons. TrkB receptors within phrenic motor neurons are necessary for BDNF-dependent acute intermittent hypoxia-induced pLTF, demonstrating that phrenic motor neurons are a critical site of respiratory motor plasticity. Copyright © 2016 Elsevier Inc. All rights reserved.

Endogenous 17β-estradiol is required for activity-dependent long-term potentiation in the striatum: interaction with the dopaminergic system

Science.gov (United States)

Tozzi, Alessandro; de Iure, Antonio; Tantucci, Michela; Durante, Valentina; Quiroga-Varela, Ana; Giampà, Carmela; Di Mauro, Michela; Mazzocchetti, Petra; Costa, Cinzia; Di Filippo, Massimiliano; Grassi, Silvarosa; Pettorossi, Vito Enrico; Calabresi, Paolo

2015-01-01

17β-estradiol (E2), a neurosteroid synthesized by P450-aromatase (ARO), modulates various brain functions. We characterized the role of the locally synthesized E2 on striatal long-term synaptic plasticity and explored possible interactions between E2 receptors (ERs) and dopamine (DA) receptors in the dorsal striatum of adult male rats. Inhibition of E2 synthesis or antagonism of ERs prevented the induction of long-term potentiation (LTP) in both medium spiny neurons (MSNs) and cholinergic interneurons (ChIs). Activation of a D1-like DA receptor/cAMP/PKA-dependent pathway restored LTP. In MSNs exogenous E2 reversed the effect of ARO inhibition. Also antagonism of M1 muscarinic receptors prevented the D1-like receptor-mediated restoration of LTP confirming a role for ChIs in controlling the E2-mediated LTP of MSNs. A novel striatal interaction, occurring between ERs and D1-like receptors in both MSNs and ChIs, might be critical to regulate basal ganglia physiology and to compensate synaptic alterations in Parkinson’s disease. PMID:26074768

Endogenous 17β-estradiol is required for activity-dependent long-term potentiation in the striatum: interaction with the dopaminergic system.

Science.gov (United States)

Tozzi, Alessandro; de Iure, Antonio; Tantucci, Michela; Durante, Valentina; Quiroga-Varela, Ana; Giampà, Carmela; Di Mauro, Michela; Mazzocchetti, Petra; Costa, Cinzia; Di Filippo, Massimiliano; Grassi, Silvarosa; Pettorossi, Vito Enrico; Calabresi, Paolo

2015-01-01

17β-estradiol (E2), a neurosteroid synthesized by P450-aromatase (ARO), modulates various brain functions. We characterized the role of the locally synthesized E2 on striatal long-term synaptic plasticity and explored possible interactions between E2 receptors (ERs) and dopamine (DA) receptors in the dorsal striatum of adult male rats. Inhibition of E2 synthesis or antagonism of ERs prevented the induction of long-term potentiation (LTP) in both medium spiny neurons (MSNs) and cholinergic interneurons (ChIs). Activation of a D1-like DA receptor/cAMP/PKA-dependent pathway restored LTP. In MSNs exogenous E2 reversed the effect of ARO inhibition. Also antagonism of M1 muscarinic receptors prevented the D1-like receptor-mediated restoration of LTP confirming a role for ChIs in controlling the E2-mediated LTP of MSNs. A novel striatal interaction, occurring between ERs and D1-like receptors in both MSNs and ChIs, might be critical to regulate basal ganglia physiology and to compensate synaptic alterations in Parkinson's disease.

Endogenous 17ß-estradiol is required for activity-dependent long-term potentiation in the striatum: interaction with the dopaminergic system

Directory of Open Access Journals (Sweden)

Alessandro eTozzi

2015-05-01

Full Text Available 17β-estradiol (E2, a neurosteroid synthesized by P450-aromatase (ARO, modulates various brain functions. We characterized the role of the locally synthesized E2 on striatal long-term synaptic plasticity and explored possible interactions between E2 receptors (ERs and dopamine (DA receptors in the dorsal striatum of adult male rats. Inhibition of E2 synthesis or antagonism of ERs prevented the induction of long-term potentiation (LTP in both medium spiny neurons (MSNs and cholinergic interneurons (ChIs. Activation of a D1-like DA receptor/cAMP/PKA-dependent pathway restored LTP. In MSNs exogenous E2 reversed the effect of ARO inhibition. Also antagonism of M1 muscarinic receptors prevented the D1-like receptor-mediated restoration of LTP confirming a role for ChIs in controlling the E2-mediated LTP of MSNs. A novel striatal interaction, occurring between ERs and D1-like receptors in both MSNs and ChIs, might be critical to regulate basal ganglia physiology and to compensate synaptic alterations in Parkinson's disease.

L-Arginine Enhances Protein Synthesis by Phosphorylating mTOR (Thr 2446 in a Nitric Oxide-Dependent Manner in C2C12 Cells

Directory of Open Access Journals (Sweden)

Ruxia Wang

2018-01-01

Full Text Available Muscle atrophy may arise from many factors such as inactivity, malnutrition, and inflammation. In the present study, we investigated the stimulatory effect of nitric oxide (NO on muscle protein synthesis. Primarily, C2C12 cells were supplied with extra L-arginine (L-Arg in the culture media. L-Arg supplementation increased the activity of inducible nitric oxide synthase (iNOS, the rate of protein synthesis, and the phosphorylation of mTOR (Thr 2446 and p70S6K (Thr 389. L-NAME, an NOS inhibitor, decreased NO concentrations within cells and abolished the stimulatory effect of L-Arg on protein synthesis and the phosphorylation of mTOR and p70S6K. In contrast, SNP (sodium nitroprusside, an NO donor, increased NO concentrations, enhanced protein synthesis, and upregulated mTOR and p70S6K phosphorylation, regardless of L-NAME treatment. Blocking mTOR with rapamycin abolished the stimulatory effect of both L-Arg and SNP on protein synthesis and p70S6K phosphorylation. These results indicate that L-Arg stimulates protein synthesis via the activation of the mTOR (Thr 2446/p70S6K signaling pathway in an NO-dependent manner.

Inducible cAMP early repressor acts as a negative regulator for kindling epileptogenesis and long-term fear memory.

Science.gov (United States)

Kojima, Nobuhiko; Borlikova, Gilyana; Sakamoto, Toshiro; Yamada, Kazuyuki; Ikeda, Toshio; Itohara, Shigeyoshi; Niki, Hiroaki; Endo, Shogo

2008-06-18

Long-lasting neuronal plasticity as well as long-term memory (LTM) requires de novo synthesis of proteins through dynamic regulation of gene expression. cAMP-responsive element (CRE)-mediated gene transcription occurs in an activity-dependent manner and plays a pivotal role in neuronal plasticity and LTM in a variety of species. To study the physiological role of inducible cAMP early repressor (ICER), a CRE-mediated gene transcription repressor, in neuronal plasticity and LTM, we generated two types of ICER mutant mice: ICER-overexpressing (OE) mice and ICER-specific knock-out (KO) mice. Both ICER-OE and ICER-KO mice show no apparent abnormalities in their development and reproduction. A comprehensive battery of behavioral tests revealed no robust changes in locomotor activity, sensory and motor functions, and emotional responses in the mutant mice. However, long-term conditioned fear memory was attenuated in ICER-OE mice and enhanced in ICER-KO mice without concurrent changes in short-term fear memory. Furthermore, ICER-OE mice exhibited retardation of kindling development, whereas ICER-KO mice exhibited acceleration of kindling. These results strongly suggest that ICER negatively regulates the neuronal processes required for long-term fear memory and neuronal plasticity underlying kindling epileptogenesis, possibly through suppression of CRE-mediated gene transcription.

Severe acute intermittent hypoxia elicits phrenic long-term facilitation by a novel adenosine-dependent mechanism

Science.gov (United States)

Nichols, Nicole L.; Dale, Erica A.

2012-01-01

Acute intermittent hypoxia [AIH; 3, 5-min episodes; 35–45 mmHg arterial Po2 (PaO2)] elicits serotonin-dependent phrenic long-term facilitation (pLTF), a form of phrenic motor facilitation (pMF) initiated by Gq protein-coupled metabotropic 5-HT2 receptors. An alternate pathway to pMF is induced by Gs protein-coupled metabotropic receptors, including adenosine A2A receptors. AIH-induced pLTF is dominated by the serotonin-dependent pathway and is actually restrained via inhibition from the adenosine-dependent pathway. Here, we hypothesized that severe AIH shifts pLTF from a serotonin-dependent to an adenosine-dependent form of pMF. pLTF induced by severe (25–30 mmHg PaO2) and moderate (45–55 mmHg PaO2) AIH were compared in anesthetized rats, with and without intrathecal (C4) spinal A2A (MSX-3, 130 ng/kg, 12 μl) or 5-HT receptor antagonist (methysergide, 300 μg/kg, 15 μl) injections. During severe, but not moderate AIH, progressive augmentation of the phrenic response during hypoxic episodes was observed. Severe AIH (78% ± 8% 90 min post-AIH, n = 6) elicited greater pLTF vs. moderate AIH (41% ± 12%, n = 8; P MSX-3 (28% ± 6%; n = 6; P 0.05). Thus severe AIH shifts pLTF from a serotonin-dependent to an adenosine-dependent mechanism; the adenosinergic pathway inhibits the serotonergic pathway following moderate AIH. Here we demonstrate a novel adenosine-dependent pathway to pLTF following severe AIH. Shifts in the mechanisms of respiratory plasticity provide the ventilatory control system greater flexibility as challenges that differ in severity are confronted. PMID:22403346

Lead (Pb+2) impairs long-term memory and blocks learning-induced increases in hippocampal protein kinase C activity

International Nuclear Information System (INIS)

Vazquez, Adrinel; Pena de Ortiz, Sandra

2004-01-01

The long-term storage of information in the brain known as long-term memory (LTM) depends on a variety of intracellular signaling cascades utilizing calcium (Ca 2+ ) and cyclic adenosine monophosphate as second messengers. In particular, Ca +2 /phospholipid-dependent protein kinase C (PKC) activity has been proposed to be necessary for the transition from short-term memory to LTM. Because the neurobehavioral toxicity of lead (Pb +2 ) has been associated to its interference with normal Ca +2 signaling in neurons, we studied its effects on spatial learning and memory using a hippocampal-dependent discrimination task. Adult rats received microinfusions of either Na + or Pb +2 acetate in the CA1 hippocampal subregion before each one of four training sessions. A retention test was given 7 days later to examine LTM. Results suggest that intrahippocampal Pb +2 did not affect learning of the task, but significantly impaired retention. The effects of Pb +2 selectively impaired reference memory measured in the retention test, but had no effect on the general performance because it did not affect the latency to complete the task during the test. Finally, we examined the effects of Pb +2 on the induction of hippocampal Ca +2 /phospholipid-dependent PKC activity during acquisition training. The results showed that Pb +2 interfered with the learning-induced activation of Ca +2 /phospholipid-dependent PKC on day 3 of acquisition. Overall, our results indicate that Pb +2 causes cognitive impairments in adult rats and that such effects might be subserved by interference with Ca +2 -related signaling mechanisms required for normal LTM

Identifying long-term memory B-cells in vaccinated children despite waning antibody levels specific for Bordetella pertussis proteins.

Science.gov (United States)

Hendrikx, Lotte H; Oztürk, Kemal; de Rond, Lia G H; Veenhoven, Reinier H; Sanders, Elisabeth A M; Berbers, Guy A M; Buisman, Anne-Marie

2011-02-04

Whooping cough is a respiratory disease caused by Bordetella pertussis. Since the 1950s in developed countries pertussis vaccinations are included in the national immunization program. However, antibody levels rapidly wane after both whole cell and acellular pertussis vaccination. Therefore protection against pertussis may depend largely on long-term B- and T-cell immunities. We investigated long-term pertussis-specific memory B-cell responses in children who were primed at infant age with the Dutch wP-vaccine (ISRCTN65428640). Purified B-cells were characterized by FACS-analysis and after polyclonal stimulation memory B-cells were detected by ELISPOT-assays specific for pertussis toxin, filamentous haemagglutinin, pertactin and tetanus. In addition, plasma IgG levels directed to the same antigens were measured by a fluorescent bead-based multiplex immunoassay. Two and 3 years after wP priming as well as 2 and 5 years after the aP booster at the age of 4, low plasma IgG levels to the pertussis proteins were found. At the same time, however pertussis protein-specific memory B-cells could be detected and their number increased with age. The number of tetanus-specific memory B-cells was similar in all age groups, whereas IgG-tetanus levels were high 2 years after tetanus booster compared to pre- and 5 years post-booster levels. This study shows the presence of long-term pertussis protein-specific memory B-cells in children despite waning antibody levels after vaccination, which suggests that memory B-cells in addition to antibodies may contribute to protection against pertussis. Copyright © 2010 Elsevier Ltd. All rights reserved.

Long-term intake of a high protein diet increases liver triacylglycerol deposition pathways and hepatic signs of injury in rats

KAUST Repository

Diaz Rua, Ruben

2017-04-19

Intake of high-protein (HP) diets has increased over the last years, mainly due to their popularity for body weight control. Liver is the main organ handling ingested macronutrients and it is associated with the beginning of different pathologies. We aimed to deepen our knowledge on molecular pathways affected by long-term intake of an HP diet. We performed a transcriptome analysis on liver of rats chronically fed with a casein-rich HP diet and analyzed molecular parameters related to liver injury. Chronic increase in the dietary protein/carbohydrate ratio up-regulated processes related with amino acid uptake/metabolism and lipid synthesis, promoting a molecular environment indicative of hepatic triacylglycerol (TG) deposition. Moreover, changes in expression of genes involved in acid–base maintenance and oxidative stress indicate alterations in the pH balance due to the high acid load of the diet, which has been linked to liver/health damage. Up-regulation of immune-related genes was also observed. In concordance with changes at gene expression level, we observed increased liver TG content and increased serum markers of hepatic injury/inflammation (aspartate transaminase, C-reactive protein and TNF-alpha). Moreover, the HP diet strongly increased hepatic mRNA and protein levels of HSP90, a marker of liver injury. Thus, we show for the first time that long-term consumption of an HP diet, resulting in a high acid load, results in a hepatic transcriptome signature reflecting increased TG deposition and increased signs of health risk (increased inflammation, alterations in the acid–base equilibrium and oxidative stress). Persistence of this altered metabolic status could have unhealthy consequences.

Long-term intake of a high protein diet increases liver triacylglycerol deposition pathways and hepatic signs of injury in rats

KAUST Repository

Diaz Rua, Ruben; Keijer, Jaap; Palou, Andreu; van Schothorst, Evert M.; Oliver, Paula

2017-01-01

Intake of high-protein (HP) diets has increased over the last years, mainly due to their popularity for body weight control. Liver is the main organ handling ingested macronutrients and it is associated with the beginning of different pathologies. We aimed to deepen our knowledge on molecular pathways affected by long-term intake of an HP diet. We performed a transcriptome analysis on liver of rats chronically fed with a casein-rich HP diet and analyzed molecular parameters related to liver injury. Chronic increase in the dietary protein/carbohydrate ratio up-regulated processes related with amino acid uptake/metabolism and lipid synthesis, promoting a molecular environment indicative of hepatic triacylglycerol (TG) deposition. Moreover, changes in expression of genes involved in acid–base maintenance and oxidative stress indicate alterations in the pH balance due to the high acid load of the diet, which has been linked to liver/health damage. Up-regulation of immune-related genes was also observed. In concordance with changes at gene expression level, we observed increased liver TG content and increased serum markers of hepatic injury/inflammation (aspartate transaminase, C-reactive protein and TNF-alpha). Moreover, the HP diet strongly increased hepatic mRNA and protein levels of HSP90, a marker of liver injury. Thus, we show for the first time that long-term consumption of an HP diet, resulting in a high acid load, results in a hepatic transcriptome signature reflecting increased TG deposition and increased signs of health risk (increased inflammation, alterations in the acid–base equilibrium and oxidative stress). Persistence of this altered metabolic status could have unhealthy consequences.

Long-term intake of a high-protein diet increases liver triacylglycerol deposition pathways and hepatic signs of injury in rats.

Science.gov (United States)

Díaz-Rúa, Rubén; Keijer, Jaap; Palou, Andreu; van Schothorst, Evert M; Oliver, Paula

2017-08-01

Intake of high-protein (HP) diets has increased over the last years, mainly due to their popularity for body weight control. Liver is the main organ handling ingested macronutrients and it is associated with the beginning of different pathologies. We aimed to deepen our knowledge on molecular pathways affected by long-term intake of an HP diet. We performed a transcriptome analysis on liver of rats chronically fed with a casein-rich HP diet and analyzed molecular parameters related to liver injury. Chronic increase in the dietary protein/carbohydrate ratio up-regulated processes related with amino acid uptake/metabolism and lipid synthesis, promoting a molecular environment indicative of hepatic triacylglycerol (TG) deposition. Moreover, changes in expression of genes involved in acid-base maintenance and oxidative stress indicate alterations in the pH balance due to the high acid load of the diet, which has been linked to liver/health damage. Up-regulation of immune-related genes was also observed. In concordance with changes at gene expression level, we observed increased liver TG content and increased serum markers of hepatic injury/inflammation (aspartate transaminase, C-reactive protein and TNF-alpha). Moreover, the HP diet strongly increased hepatic mRNA and protein levels of HSP90, a marker of liver injury. Thus, we show for the first time that long-term consumption of an HP diet, resulting in a high acid load, results in a hepatic transcriptome signature reflecting increased TG deposition and increased signs of health risk (increased inflammation, alterations in the acid-base equilibrium and oxidative stress). Persistence of this altered metabolic status could have unhealthy consequences. Copyright © 2017 Elsevier Inc. All rights reserved.

Successful treatment of dwarfism secondary to long-term steroid therapy in steroid-dependent nephrotic syndrome.

Science.gov (United States)

Sun, Linlin; Chen, Dongping; Zhao, Xuezhi; Xu, Chenggang; Mei, Changlin

2010-01-01

Prolonged steroid therapy is generally used for steroid-dependent nephrotic syndrome in pediatric patients. However, dwarfism secondary to a long-term regimen and its successful reverse is rarely reported. The underlying mechanism of dwarfism is still poorly understood, as both long-term steroid use and nephrotic syndrome may interact or independently interfere with the process of growth. Here, we present a 17-year-old patient with dwarfism and steroid-dependent nephrotic syndrome and the successful treatment by recombinant human growth factor and cyclosporine A with withdrawal of steroid. We also briefly review the current understanding and the management of dwarfism in pediatric patients with nephrotic syndrome.

Roles of Fe-S proteins: from cofactor synthesis to iron homeostasis to protein synthesis.

Science.gov (United States)

Pain, Debkumar; Dancis, Andrew

2016-06-01

Fe-S cluster assembly is an essential process for all cells. Impairment of Fe-S cluster assembly creates diseases in diverse and surprising ways. In one scenario, the loss of function of lipoic acid synthase, an enzyme with Fe-S cluster cofactor in mitochondria, impairs activity of various lipoamide-dependent enzymes with drastic consequences for metabolism. In a second scenario, the heme biosynthetic pathway in red cell precursors is specifically targeted, and iron homeostasis is perturbed, but lipoic acid synthesis is unaffected. In a third scenario, tRNA modifications arising from action of the cysteine desulfurase and/or Fe-S cluster proteins are lost, which may lead to impaired protein synthesis. These defects can then result in cancer, neurologic dysfunction or type 2 diabetes. Copyright © 2016 Elsevier Ltd. All rights reserved.

Effect of long-term refeeding on protein metabolism in patients with cirrhosis of the liver

DEFF Research Database (Denmark)

Kondrup, J; Nielsen, K; Juul, A

1997-01-01

, protein requirement and protein utilization were investigated further by measuring protein synthesis and degradation. In two separate studies, five or six patients with cirrhosis of the liver were refed on a balanced diet for an average of 2 or 4 weeks. Protein and energy intakes were doubled in both...... studies. Initial and final whole-body protein metabolism was measured in the fed state by primed continuous [15N]glycine infusion. Refeeding caused a statistically significant increase of about 30% in protein synthesis in both studies while protein degradation was only slightly affected. The increase...... in protein synthesis was associated with significant increases in plasma concentrations of total amino acids (25%), leucine (58%), isoleucine (82%), valine (72%), proline (48%) and triiodothyronine (27%) while insulin, growth hormone, insulin-like growth factor (IGF)-I and IGF-binding protein-3 were...

Repeated pulses of serotonin required for long-term facilitation activate mitogen-activated protein kinase in sensory neurons of Aplysia

Science.gov (United States)

Michael, Dan; Martin, Kelsey C.; Seger, Rony; Ning, Ming-Ming; Baston, Rene; Kandel, Eric R.

1998-01-01

Long-term facilitation of the connections between the sensory and motor neurons of the gill-withdrawal reflex in Aplysia requires five repeated pulses of serotonin (5-HT). The repeated pulses of 5-HT initiate a cascade of gene activation that leads ultimately to the growth of new synaptic connections. Several genes in this process have been identified, including the transcriptional regulators apCREB-1, apCREB-2, apC/EBP, and the cell adhesion molecule apCAM, which is thought to be involved in the formation of new synaptic connections. Here we report that the transcriptional regulators apCREB-2 and apC/EBP, as well as a peptide derived from the cytoplasmic domain of apCAM, are phosphorylated in vitro by Aplysia mitogen-activated protein kinase (apMAPK). We have cloned the cDNA encoding apMAPK and show that apMAPK activity is increased in sensory neurons treated with repeated pulses of 5-HT and by the cAMP pathway. These results suggest that apMAPK may participate with cAMP-dependent protein kinase during long-term facilitation in sensory cells by modifying some of the key elements involved in the consolidation of short- to long-lasting changes in synaptic strength. PMID:9465108

Response of rat brain protein synthesis to ethanol and sodium barbital

International Nuclear Information System (INIS)

Tewari, S.; Greenberg, S.A.; Do, K.; Grey, P.A.

1987-01-01

Central nervous system (CNS) depressants such as ethanol and barbiturates under acute or chronic conditions can induce changes in rat brain protein synthesis. While these data demonstrate the individual effects of drugs on protein synthesis, the response of brain protein synthesis to alcohol-drug interactions is not known. The goal of the present study was to determine the individual and combined effects of ethanol and sodium barbital on brain protein synthesis and gain an understanding of the mechanisms by which these alterations in protein synthesis are produced. Specifically, the in vivo and in vitro effects of sodium barbital (one class of barbiturates which is not metabolized by the hepatic tissue) were examined on brain protein synthesis in rats made physically dependent upon ethanol. Using cell free brain polysomal systems isolated from Control, Ethanol and 24 h Ethanol Withdrawn rats, data show that sodium barbital, when intubated intragastrically, inhibited the time dependent incorporation of 14 C) leucine into protein by all three groups of ribosomes. Under these conditions, the Ethanol Withdrawn group displayed the largest inhibition of the 14 C) leucine incorporation into protein when compared to the Control and Ethanol groups. In addition, sodium barbital when added at various concentrations in vitro to the incubation medium inhibited the incorporation of 14 C) leucine into protein by Control and Ethanol polysomes. The inhibitory effects were also obtained following preincubation of ribosomes in the presence of barbital but not cycloheximide. Data suggest that brain protein synthesis, specifically brain polysomes, through interaction with ethanol or barbital are involved in the functional development of tolerance. These interactions may occur through proteins or polypeptide chains or alterations in messenger RNA components associated with the ribosomal units

Covered interest parity arbitrage and temporal long-term dependence between the US dollar and the Yen

Science.gov (United States)

Batten, Jonathan A.; Szilagyi, Peter G.

2007-03-01

Using a daily time series from 1983 to 2005 of currency prices in spot and forward USD/Yen markets and matching equivalent maturity short-term US and Japanese interest rates, we investigate the sensitivity of the difference between actual prices in forward markets to those calculated from differentials in short-term interest rates. According to a fundamental theorem in financial economics termed covered interest parity (CIP), the actual and estimated prices should be identical once transaction and other costs are accommodated. The paper presents three important findings: first, we find evidence of considerable variation in CIP deviations from equilibrium; second, these deviations have diminished significantly and by 2000 have been almost eliminated; third, an analysis of the CIP deviations using the local Hurst exponent finds episodes of time-varying dependence over the various sample periods, which appear to be linked to episodes of dollar decline/Yen appreciation, or vice versa. The finding of temporal long-term dependence in CIP deviations is consistent with recent evidence of temporal long-term dependence in the returns of currency, stock and commodity markets.

Long-term persistence, density dependence and effects of climate change on rosyside dace (Cyprinidae)

Science.gov (United States)

Gary D. Grossman; Gary Sundin; Robert E. Ratajczak

2016-01-01

SummaryWe used long-term population data for rosyside dace (Clinostomus funduloides), a numerically dominant member of a stochastically organised fish assemblage, to evaluate the relative importance of density-dependent and density-independent processes to population...

Layer 2/3 synapses in monocular and binocular regions of tree shrew visual cortex express mAChR-dependent long-term depression and long-term potentiation.

Science.gov (United States)

McCoy, Portia; Norton, Thomas T; McMahon, Lori L

2008-07-01

Acetylcholine is an important modulator of synaptic efficacy and is required for learning and memory tasks involving the visual cortex. In rodent visual cortex, activation of muscarinic acetylcholine receptors (mAChRs) induces a persistent long-term depression (LTD) of transmission at synapses recorded in layer 2/3 of acute slices. Although the rodent studies expand our knowledge of how the cholinergic system modulates synaptic function underlying learning and memory, they are not easily extrapolated to more complex visual systems. Here we used tree shrews for their similarities to primates, including a visual cortex with separate, defined regions of monocular and binocular innervation, to determine whether mAChR activation induces long-term plasticity. We find that the cholinergic agonist carbachol (CCh) not only induces long-term plasticity, but the direction of the plasticity depends on the subregion. In the monocular region, CCh application induces LTD of the postsynaptic potential recorded in layer 2/3 that requires activation of m3 mAChRs and a signaling cascade that includes activation of extracellular signal-regulated kinase (ERK) 1/2. In contrast, layer 2/3 postsynaptic potentials recorded in the binocular region express long-term potentiation (LTP) following CCh application that requires activation of m1 mAChRs and phospholipase C. Our results show that activation of mAChRs induces long-term plasticity at excitatory synapses in tree shrew visual cortex. However, depending on the ocular inputs to that region, variation exists as to the direction of plasticity, as well as to the specific mAChR and signaling mechanisms that are required.

Ammonia inhibits long-term potentiation via neurosteroid synthesis in hippocampal pyramidal neurons.

Science.gov (United States)

Izumi, Y; Svrakic, N; O'Dell, K; Zorumski, C F

2013-03-13

Neurosteroids are a class of endogenous steroids synthesized in the brain that are believed to be involved in the pathogenesis of neuropsychiatric disorders and memory impairment. Ammonia impairs long-term potentiation (LTP), a synaptic model of learning, in the hippocampus, a brain region involved in memory acquisition. Although mechanisms underlying ammonia-mediated LTP inhibition are not fully understood, we previously found that the activation of N-methyl-d-aspartate receptors (NMDARs) is important. Based on this, we hypothesize that metabolic stressors, including hyperammonemia, promote untimely NMDAR activation and result in neural adaptations that include the synthesis of allopregnanolone (alloP) and other GABA-potentiating neurosteroids that dampen neuronal activity and impair LTP and memory formation. Using an antibody against 5α-reduced neurosteroids, we found that 100 μM ammonia acutely enhanced neurosteroid immunostaining in pyramidal neurons in the CA1 region of rat hippocampal slices. The enhanced staining was blocked by finasteride, a selective inhibitor of 5α-reductase, a key enzyme required for alloP synthesis. Finasteride also overcame LTP inhibition by 100 μM ammonia, as did picrotoxin, an inhibitor of GABA-A receptors. These results indicate that GABA-enhancing neurosteroids, synthesized locally within pyramidal neurons, contribute significantly to ammonia-mediated synaptic dysfunction. These results suggest that the manipulation of neurosteroid synthesis could provide a strategy to improve cognitive function in individuals with hyperammonemia. Copyright © 2012 IBRO. Published by Elsevier Ltd. All rights reserved.

Rapid-rate transcranial magnetic stimulation of animal auditory cortex impairs short-term but not long-term memory formation.

Science.gov (United States)

Wang, Hong; Wang, Xu; Wetzel, Wolfram; Scheich, Henning

2006-04-01

Bilateral rapid-rate transcranial magnetic stimulation (rTMS) of gerbil auditory cortex with a miniature coil device was used to study short-term and long-term effects on discrimination learning of frequency-modulated tones. We found previously that directional discrimination of frequency modulation (rising vs. falling) relies on auditory cortex processing and that formation of its memory depends on local protein synthesis. Here we show that, during training over 5 days, certain rTMS regimes contingent on training had differential effects on the time course of learning. When rTMS was applied several times per day, i.e. four blocks of 5 min rTMS each followed 5 min later by a 3-min training block and 15-min intervals between these blocks (experiment A), animals reached a high discrimination performance more slowly over 5 days than did controls. When rTMS preceded only the first two of four training blocks (experiment B), or when prolonged rTMS (20 min) preceded only the first block, or when blocks of experiment A had longer intervals (experiments C and D), no significant day-to-day effects were found. However, in experiment A, and to some extent in experiment B, rTMS reduced the within-session discrimination performance. Nevertheless the animals learned, as demonstrated by a higher performance the next day. Thus, our results indicate that rTMS treatments accumulate over a day but not strongly over successive days. We suggest that rTMS of sensory cortex, as used in our study, affects short-term memory but not long-term memory formation.

Design, synthesis, and evaluation of an alpha-helix mimetic library targeting protein-protein interactions.

Science.gov (United States)

Shaginian, Alex; Whitby, Landon R; Hong, Sukwon; Hwang, Inkyu; Farooqi, Bilal; Searcey, Mark; Chen, Jiandong; Vogt, Peter K; Boger, Dale L

2009-04-22

The design and solution-phase synthesis of an alpha-helix mimetic library as an integral component of a small-molecule library targeting protein-protein interactions are described. The iterative design, synthesis, and evaluation of the candidate alpha-helix mimetic was initiated from a precedented triaryl template and refined by screening the designs for inhibition of MDM2/p53 binding. Upon identifying a chemically and biologically satisfactory design and consistent with the screening capabilities of academic collaborators, the corresponding complete library was assembled as 400 mixtures of 20 compounds (20 x 20 x 20-mix), where the added subunits are designed to mimic all possible permutations of the naturally occurring i, i + 4, i + 7 amino acid side chains of an alpha-helix. The library (8000 compounds) was prepared using a solution-phase synthetic protocol enlisting acid/base liquid-liquid extractions for purification on a scale that insures its long-term availability for screening campaigns. Screening of the library for inhibition of MDM2/p53 binding not only identified the lead alpha-helix mimetic upon which the library was based, but also suggests that a digestion of the initial screening results that accompany the use of such a comprehensive library can provide insights into the nature of the interaction (e.g., an alpha-helix mediated protein-protein interaction) and define the key residues and their characteristics responsible for recognition.

Selective inhibition of influenza virus protein synthesis by inhibitors of DNA function

International Nuclear Information System (INIS)

Minor, P.D.; Dimmock, N.J.

1977-01-01

Various known inhibitors of cellular DNA function were shown to inhibit cellular RNA synthesis and influenza (fowl plague) virus multiplication. The drugs were investigated for their effect upon the synthesis of influenza virus proteins. According to this effect they could be classified with previously studied compounds as follows: Group I (ethidium bromide, proflavine, and N-nitroquinoline-N-oxide) inhibited both viral and cellular protein synthesis; Group II (nogalomycin, daunomycin and α-amanitin) inhibited viral but not cellular protein synthesis, and all viral proteins were inhibited coordinately; Group III (mithramycin, echinomycin, and actinomycin D) inhibited all viral but not cellular protein synthesis at high concentrations, but at a lower critical concentration inhibited the synthesis of viral haemagglutinin, neuraminidase, and M protein preferentially; Group IV(uv irradiation and camptothecin) inhibited the synthesis of viral haemagglutinin, neuraminidase, and M protein, but not other viral proteins, even at high doses. The mode of action of these inhibitors is discussed in relation to the mechanism of the nuclear events upon which influenza virus multiplication is dependent

Metabolic shifts in the myocardium in the long-term effect of atmospheric pollution on the body

Energy Technology Data Exchange (ETDEWEB)

Tsapok, P I; Turdakin, P G; Barkov, L V; Ovcharuk, I N; Protod' iakonova, T N

1981-04-01

Metabolic shifts in the myocardium under conditions of long-term exposure of the body to air pollution were studied in experiments on albino rats. Study of the content of protein, RNA, DNA, glycogen, ATP, lactic and pyruvic acids and the activity of lactate dehydrogenase and creatine kinase in the heart muscle allowed the conclusion that the glycolytic processes are intensified, the bioenergic processes are inhibited and the synthesis of protein and RNA are increased in the myocardium of the experimental animals.

Target-Dependent Structural Changes Accompanying Long-Term Synaptic Facilitation in Aplysia Neurons

Science.gov (United States)

Glanzman, David L.; Kandel, Eric R.; Schacher, Samuel

1990-08-01

The mechanisms underlying structural changes that accompany learning and memory have been difficult to investigate in the intact nervous system. In order to make these changes more accessible for experimental analysis, dissociated cell culture and low-light-level video microscopy were used to examine Aplysia sensory neurons in the presence or absence of their target cells. Repeated applications of serotonin, a facilitating transmitter important in behavioral dishabituation and sensitization, produced growth of the sensory neurons that paralleled the long-term enhancement of synaptic strength. This growth required the presence of the postsynaptic motor neuron. Thus, both the structural changes and the synaptic facilitation of Aplysia sensorimotor synapses accompanying long-term behavioral sensitization can be produced in vitro by applying a single facilitating transmitter repeatedly. These structural changes depend on an interaction of the presynaptic neuron with an appropriate postsynaptic target.

The ERM protein Moesin is essential for neuronal morphogenesis and long-term memory in Drosophila.

Science.gov (United States)

Freymuth, Patrick S; Fitzsimons, Helen L

2017-08-29

Moesin is a cytoskeletal adaptor protein that plays an important role in modification of the actin cytoskeleton. Rearrangement of the actin cytoskeleton drives both neuronal morphogenesis and the structural changes in neurons that are required for long-term memory formation. Moesin has been identified as a candidate memory gene in Drosophila, however, whether it is required for memory formation has not been evaluated. Here, we investigate the role of Moesin in neuronal morphogenesis and in short- and long-term memory formation in the courtship suppression assay, a model of associative memory. We found that both knockdown and overexpression of Moesin led to defects in axon growth and guidance as well as dendritic arborization. Moreover, reduction of Moesin expression or expression of a constitutively active phosphomimetic in the adult Drosophila brain had no effect on short term memory, but prevented long-term memory formation, an effect that was independent of its role in development. These results indicate a critical role for Moesin in both neuronal morphogenesis and long-term memory formation.

Injury-induced inhibition of small intestinal protein and nucleic acid synthesis

International Nuclear Information System (INIS)

Carter, E.A.; Hatz, R.A.; Yarmush, M.L.; Tompkins, R.G.

1990-01-01

Small intestinal mucosal weight and nutrient absorption are significantly diminished early after cutaneous thermal injuries. Because these intestinal properties are highly dependent on rates of nucleic acid and protein synthesis, in vivo incorporation of thymidine, uridine, and leucine into small intestinal deoxyribonucleic acid, ribonucleic acid, and proteins were measured. Deoxyribonucleic acid synthesis was markedly decreased with the lowest thymidine incorporation in the jejunum (p less than 0.01); these findings were confirmed by autoradiographic identification of radiolabeled nuclei in the intestinal crypts. Protein synthesis was decreased by 6 h postinjury (p less than 0.01) but had returned to normal by 48 h. Consistent with a decreased rate of protein synthesis, ribonucleic acid synthesis was also decreased 18 h postinjury (p less than 0.01). These decreased deoxyribonucleic acid, ribonucleic acid, and protein synthesis rates are not likely a result of ischemia because in other studies of this injury model, intestinal blood flow was not significantly changed by the burn injury. Potentially, factors initiating the acute inflammatory reaction may directly inhibit nucleic acid and protein synthesis and lead to alterations in nutrient absorption and intestinal barrier function after injury

Whey protein supplementation preserves postprandial myofibrillar protein synthesis during short-term energy restriction in overweight and obese adults.

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Hector, Amy J; Marcotte, George R; Churchward-Venne, Tyler A; Murphy, Caoileann H; Breen, Leigh; von Allmen, Mark; Baker, Steven K; Phillips, Stuart M

2015-02-01

Higher dietary energy as protein during weight loss results in a greater loss of fat mass and retention of muscle mass; however, the impact of protein quality on the rates of myofibrillar protein synthesis (MPS) and lipolysis, processes that are important in the maintenance of muscle and loss of fat, respectively, are unknown. We aimed to determine how the consumption of different sources of proteins (soy or whey) during a controlled short-term (14-d) hypoenergetic diet affected MPS and lipolysis. Men (n = 19) and women (n = 21) (age 35-65 y; body mass index 28-50 kg/m(2)) completed a 14-d controlled hypoenergetic diet (-750 kcal/d). Participants were randomly assigned, double blind, to receive twice-daily supplements of isolated whey (27 g/supplement) or soy (26 g/supplement), providing a total protein intake of 1.3 ± 0.1 g/(kg · d), or isoenergetic carbohydrate (25 g maltodextrin/supplement) resulting in a total protein intake of 0.7 ± 0.1 g/(kg · d). Before and after the dietary intervention, primed continuous infusions of L-[ring-(13)C6] phenylalanine and [(2)H5]-glycerol were used to measure postabsorptive and postprandial rates of MPS and lipolysis. Preintervention, MPS was stimulated more (P whey than with soy or carbohydrate. Postintervention, postabsorptive MPS decreased similarly in all groups (all P whey group, which was less (P whey. We conclude that whey protein supplementation attenuated the decline in postprandial rates of MPS after weight loss, which may be of importance in the preservation of lean mass during longer-term weight loss interventions. This trial was registered at clinicaltrials.gov as NCT01530646. © 2015 American Society for Nutrition.

Density-dependent microbial turnover improves soil carbon model predictions of long-term litter manipulations

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Georgiou, Katerina; Abramoff, Rose; Harte, John; Riley, William; Torn, Margaret

2017-04-01

Climatic, atmospheric, and land-use changes all have the potential to alter soil microbial activity via abiotic effects on soil or mediated by changes in plant inputs. Recently, many promising microbial models of soil organic carbon (SOC) decomposition have been proposed to advance understanding and prediction of climate and carbon (C) feedbacks. Most of these models, however, exhibit unrealistic oscillatory behavior and SOC insensitivity to long-term changes in C inputs. Here we diagnose the sources of instability in four models that span the range of complexity of these recent microbial models, by sequentially adding complexity to a simple model to include microbial physiology, a mineral sorption isotherm, and enzyme dynamics. We propose a formulation that introduces density-dependence of microbial turnover, which acts to limit population sizes and reduce oscillations. We compare these models to results from 24 long-term C-input field manipulations, including the Detritus Input and Removal Treatment (DIRT) experiments, to show that there are clear metrics that can be used to distinguish and validate the inherent dynamics of each model structure. We find that widely used first-order models and microbial models without density-dependence cannot readily capture the range of long-term responses observed across the DIRT experiments as a direct consequence of their model structures. The proposed formulation improves predictions of long-term C-input changes, and implies greater SOC storage associated with CO2-fertilization-driven increases in C inputs over the coming century compared to common microbial models. Finally, we discuss our findings in the context of improving microbial model behavior for inclusion in Earth System Models.

Long term weight maintenance after advice to consume low carbohydrate, higher protein diets--a systematic review and meta analysis.

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Clifton, P M; Condo, D; Keogh, J B

2014-03-01

Meta analysis of short term trials indicates that a higher protein, lower carbohydrate weight loss diet enhances fat mass loss and limits lean mass loss compared with a normal protein weight loss diet. Whether this benefit persists long term is not clear. We selected weight loss studies in adults with at least a 12 month follow up in which a higher percentage protein/lower carbohydrate diet was either planned or would be expected for either weight loss or weight maintenance. Studies were selected regardless of the success of the advice but difference in absolute and percentage protein intake at 12 months was used as a moderator in the analysis. Data was analysed using Comprehensive Meta analysis V2 using a random effects analysis. As many as 32 studies with 3492 individuals were analysed with data on fat and lean mass, glucose and insulin from 18 to 22 studies and lipids from 28 studies. A recommendation to consume a lower carbohydrate, higher protein diet in mostly short term intensive interventions with long term follow up was associated with better weight and fat loss but the effect size was small-standardised means of 0.14 and 0.22, p = 0.008 and p fat mass (0.9 vs. 0.3 kg). Fasting triglyceride and insulin were also lower with high protein diets with effect sizes of 0.17 and 0.22, p = 0.003 and p = 0.042 respectively. Other lipids and glucose were not different. The short term benefit of higher protein diets appears to persist to a small degree long term. Benefits are greater with better compliance to the diet. Copyright © 2013 Elsevier B.V. All rights reserved.

GABAergic activities control spike timing- and frequency-dependent long-term depression at hippocampal excitatory synapses

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Makoto Nishiyama

2010-06-01

Full Text Available GABAergic interneuronal network activities in the hippocampus control a variety of neural functions, including learning and memory, by regulating θ and γ oscillations. How these GABAergic activities at pre- and post-synaptic sites of hippocampal CA1 pyramidal cells differentially contribute to synaptic function and plasticity during their repetitive pre- and post-synaptic spiking at θ and γ oscillations is largely unknown. We show here that activities mediated by postsynaptic GABAARs and presynaptic GABABRs determine, respectively, the spike timing- and frequency-dependence of activity-induced synaptic modifications at Schaffer collateral-CA1 excitatory synapses. We demonstrate that both feedforward and feedback GABAAR-mediated inhibition in the postsynaptic cell controls the spike timing-dependent long-term depression of excitatory inputs (“e-LTD” at the θ frequency. We also show that feedback postsynaptic inhibition specifically causes e-LTD of inputs that induce small postsynaptic currents (<70 pA with LTP timing, thus enforcing the requirement of cooperativity for induction of long-term potentiation at excitatory inputs (“e-LTP”. Furthermore, under spike-timing protocols that induce e-LTP and e-LTD at excitatory synapses, we observed parallel induction of LTP and LTD at inhibitory inputs (“i-LTP” and “i-LTD” to the same postsynaptic cells. Finally, we show that presynaptic GABABR-mediated inhibition plays a major role in the induction of frequency-dependent e-LTD at α and β frequencies. These observations demonstrate the critical influence of GABAergic interneuronal network activities in regulating the spike timing and frequency dependences of long-term synaptic modifications in the hippocampus.

BDNF-induced local protein synthesis and synaptic plasticity.

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Leal, Graciano; Comprido, Diogo; Duarte, Carlos B

2014-01-01

Brain-derived neurotrophic factor (BDNF) is an important regulator of synaptic transmission and long-term potentiation (LTP) in the hippocampus and in other brain regions, playing a role in the formation of certain forms of memory. The effects of BDNF in LTP are mediated by TrkB (tropomyosin-related kinase B) receptors, which are known to be coupled to the activation of the Ras/ERK, phosphatidylinositol 3-kinase/Akt and phospholipase C-γ (PLC-γ) pathways. The role of BDNF in LTP is best studied in the hippocampus, where the neurotrophin acts at pre- and post-synaptic levels. Recent studies have shown that BDNF regulates the transport of mRNAs along dendrites and their translation at the synapse, by modulating the initiation and elongation phases of protein synthesis, and by acting on specific miRNAs. Furthermore, the effect of BDNF on transcription regulation may further contribute to long-term changes in the synaptic proteome. In this review we discuss the recent progress in understanding the mechanisms contributing to the short- and long-term regulation of the synaptic proteome by BDNF, and the role in synaptic plasticity, which is likely to influence learning and memory formation. This article is part of the Special Issue entitled 'BDNF Regulation of Synaptic Structure, Function, and Plasticity'. Copyright © 2013 Elsevier Ltd. All rights reserved.

Mechanisms of isoform-specific Na/K pump regulation by short- and long-term adrenergic activation in rat ventricular myocytes.

Science.gov (United States)

Yin, Jian; Guo, Hui-Cai; Yu, Ding; Wang, Hui-Ci; Li, Jun-Xia; Wang, Yong-Li

2014-01-01

Many stressful conditions, including cardiovascular diseases, induce long-term elevations in circulating catecholamines, thereby leading to changes of the Na/K pump and thus affecting myocardial functions. However, only short-term adrenergic regulation of the Na/K pump has been reported. The present study is the first investigation of long-term adrenergic regulation of the Na/K pump and the potential mechanism. After acutely isolated Sprague-Dawley rat myocytes were incubated with noradrenaline or isoprenaline for 24 h, Na/K pump high- (IPH) and low-affinity current (IPL), α-isoform mRNA, and α-isoform protein were examined using patch-clamp, RT-PCR, and Western blotting techniques, respectively. After the short-term incubation, isoprenaline reduced the IPL through a PKA-dependent pathway that involves α1-isoform translocation from the membrane to early endosomes, and noradrenaline increased the IPH through a PKC-dependent pathway that involves α2-isoform translocation from late endosomes to the membrane. After long-term incubation, isoprenaline increased the IPL, α1-isoform mRNA, and α1-isoform protein, and noradrenaline reduced the IPH, α2-isoform mRNA, and α1-isoform protein through a PKA-or PKC-dependent pathway, respectively. These results suggest that long-term adrenergic Na/K pump regulation is isoform-specific and negatively feeds back on the short-term response. Furthermore, long-term regulation involves transcription and translation of the respective α-isoform, whereas short-term regulation involves the translocation of the available α-isoform to the plasma membrane. © 2014 S. Karger AG, Basel.

Mechanisms of Isoform-Specific Na/K Pump Regulation by Short- and Long-Term Adrenergic Activation in Rat Ventricular Myocytes

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Jian Yin

2014-05-01

Full Text Available Background: Many stressful conditions, including cardiovascular diseases, induce long-term elevations in circulating catecholamines, thereby leading to changes of the Na/K pump and thus affecting myocardial functions. However, only short-term adrenergic regulation of the Na/K pump has been reported. The present study is the first investigation of long-term adrenergic regulation of the Na/K pump and the potential mechanism. Methods: After acutely isolated Sprague-Dawley rat myocytes were incubated with noradrenaline or isoprenaline for 24 h, Na/K pump high- (IPH and low-affinity current (IPL, α-isoform mRNA, and α-isoform protein were examined using patch-clamp, RT-PCR, and Western blotting techniques, respectively. Results: After the short-term incubation, isoprenaline reduced the IPL through a PKA-dependent pathway that involves α1-isoform translocation from the membrane to early endosomes, and noradrenaline increased the IPH through a PKC-dependent pathway that involves α2-isoform translocation from late endosomes to the membrane. After long-term incubation, isoprenaline increased the IPL, α1-isoform mRNA, and α1-isoform protein, and noradrenaline reduced the IPH, α2-isoform mRNA, and α1-isoform protein through a PKA-or PKC-dependent pathway, respectively. Conclusions: These results suggest that long-term adrenergic Na/K pump regulation is isoform-specific and negatively feeds back on the short-term response. Furthermore, long-term regulation involves transcription and translation of the respective α-isoform, whereas short-term regulation involves the translocation of the available α-isoform to the plasma membrane.

ATM Protein Physically and Functionally Interacts with Proliferating Cell Nuclear Antigen to Regulate DNA Synthesis*

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Gamper, Armin M.; Choi, Serah; Matsumoto, Yoshihiro; Banerjee, Dibyendu; Tomkinson, Alan E.; Bakkenist, Christopher J.

2012-01-01

Ataxia telangiectasia (A-T) is a pleiotropic disease, with a characteristic hypersensitivity to ionizing radiation that is caused by biallelic mutations in A-T mutated (ATM), a gene encoding a protein kinase critical for the induction of cellular responses to DNA damage, particularly to DNA double strand breaks. A long known characteristic of A-T cells is their ability to synthesize DNA even in the presence of ionizing radiation-induced DNA damage, a phenomenon termed radioresistant DNA synthesis. We previously reported that ATM kinase inhibition, but not ATM protein disruption, blocks sister chromatid exchange following DNA damage. We now show that ATM kinase inhibition, but not ATM protein disruption, also inhibits DNA synthesis. Investigating a potential physical interaction of ATM with the DNA replication machinery, we found that ATM co-precipitates with proliferating cell nuclear antigen (PCNA) from cellular extracts. Using bacterially purified ATM truncation mutants and in vitro translated PCNA, we showed that the interaction is direct and mediated by the C terminus of ATM. Indeed, a 20-amino acid region close to the kinase domain is sufficient for strong binding to PCNA. This binding is specific to ATM, because the homologous regions of other PIKK members, including the closely related kinase A-T and Rad3-related (ATR), did not bind PCNA. ATM was found to bind two regions in PCNA. To examine the functional significance of the interaction between ATM and PCNA, we tested the ability of ATM to stimulate DNA synthesis by DNA polymerase δ, which is implicated in both DNA replication and DNA repair processes. ATM was observed to stimulate DNA polymerase activity in a PCNA-dependent manner. PMID:22362778

Hampered long-term depression and thin spine loss in the nucleus accumbens of ethanol-dependent rats.

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Spiga, Saturnino; Talani, Giuseppe; Mulas, Giovanna; Licheri, Valentina; Fois, Giulia R; Muggironi, Giulia; Masala, Nicola; Cannizzaro, Carla; Biggio, Giovanni; Sanna, Enrico; Diana, Marco

2014-09-02

Alcoholism involves long-term cognitive deficits, including memory impairment, resulting in substantial cost to society. Neuronal refinement and stabilization are hypothesized to confer resilience to poor decision making and addictive-like behaviors, such as excessive ethanol drinking and dependence. Accordingly, structural abnormalities are likely to contribute to synaptic dysfunctions that occur from suddenly ceasing the use of alcohol after chronic ingestion. Here we show that ethanol-dependent rats display a loss of dendritic spines in medium spiny neurons of the nucleus accumbens (Nacc) shell, accompanied by a reduction of tyrosine hydroxylase immunostaining and postsynaptic density 95-positive elements. Further analysis indicates that "long thin" but not "mushroom" spines are selectively affected. In addition, patch-clamp experiments from Nacc slices reveal that long-term depression (LTD) formation is hampered, with parallel changes in field potential recordings and reductions in NMDA-mediated synaptic currents. These changes are restricted to the withdrawal phase of ethanol dependence, suggesting their relevance in the genesis of signs and/or symptoms affecting ethanol withdrawal and thus the whole addictive cycle. Overall, these results highlight the key role of dynamic alterations in dendritic spines and their presynaptic afferents in the evolution of alcohol dependence. Furthermore, they suggest that the selective loss of long thin spines together with a reduced NMDA receptor function may affect learning. Disruption of this LTD could contribute to the rigid emotional and motivational state observed in alcohol dependence.

Impaired fear memory specificity associated with deficient endocannabinoid-dependent long-term plasticity.

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Lovelace, Jonathan W; Vieira, Philip A; Corches, Alex; Mackie, Ken; Korzus, Edward

2014-06-01

In addition to its central role in learning and memory, N-methyl D-aspartate receptor (NMDAR)-dependent signaling regulates central glutamatergic synapse maturation and has been implicated in schizophrenia. We have transiently induced NMDAR hypofunction in infant mice during postnatal days 7-11, followed by testing fear memory specificity and presynaptic plasticity in the prefrontal cortex (PFC) in adult mice. We show that transient NMDAR hypofunction during early brain development, coinciding with the maturation of cortical plasticity results in a loss of an endocannabinoid (eCB)-mediated form of long-term depression (eCB-LTD) at adult central glutamatergic synapses, while another form of presynaptic long-term depression mediated by the metabotropic glutamate receptor 2/3 (mGluR2/3-LTD) remains intact. Mice with this selective impairment of presynaptic plasticity also showed deficits in fear memory specificity. The observed deficit in cortical presynaptic plasticity may represent a neural maladaptation contributing to network instability and abnormal cognitive functioning.

Intermittent apnea elicits inactivity-induced phrenic motor facilitation via a retinoic acid- and protein synthesis-dependent pathway.

Science.gov (United States)

Baertsch, Nathan A; Baker, Tracy L

2017-11-01

Respiratory motoneuron pools must provide rhythmic inspiratory drive that is robust and reliable, yet dynamic enough to respond to respiratory challenges. One form of plasticity that is hypothesized to contribute to motor output stability by sensing and responding to inadequate respiratory neural activity is inactivity-induced phrenic motor facilitation (iPMF), an increase in inspiratory output triggered by a reduction in phrenic synaptic inputs. Evidence suggests that mechanisms giving rise to iPMF differ depending on the pattern of reduced respiratory neural activity (i.e., neural apnea). A prolonged neural apnea elicits iPMF via a spinal TNF-α-induced increase in atypical PKC activity, but little is known regarding mechanisms that elicit iPMF following intermittent neural apnea. We tested the hypothesis that iPMF triggered by intermittent neural apnea requires retinoic acid and protein synthesis. Phrenic nerve activity was recorded in urethane-anesthetized and -ventilated rats treated intrathecally with an inhibitor of retinoic acid synthesis (4-diethlyaminobenzaldehyde, DEAB), a protein synthesis inhibitor (emetine), or vehicle (artificial cerebrospinal fluid) before intermittent (5 episodes, ~1.25 min each) or prolonged (30 min) neural apnea. Both DEAB and emetine abolished iPMF elicited by intermittent neural apnea but had no effect on iPMF elicited by a prolonged neural apnea. Thus different patterns of reduced respiratory neural activity elicit phenotypically similar iPMF via distinct spinal mechanisms. Understanding mechanisms that allow respiratory motoneurons to dynamically tune their output may have important implications in the context of respiratory control disorders that involve varied patterns of reduced respiratory neural activity, such as central sleep apnea and spinal cord injury. NEW & NOTEWORTHY We identify spinal retinoic acid and protein synthesis as critical components in the cellular cascade whereby repetitive reductions in respiratory

Strong Selection Significantly Increases Epistatic Interactions in the Long-Term Evolution of a Protein.

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Aditi Gupta

2016-03-01

Full Text Available Epistatic interactions between residues determine a protein's adaptability and shape its evolutionary trajectory. When a protein experiences a changed environment, it is under strong selection to find a peak in the new fitness landscape. It has been shown that strong selection increases epistatic interactions as well as the ruggedness of the fitness landscape, but little is known about how the epistatic interactions change under selection in the long-term evolution of a protein. Here we analyze the evolution of epistasis in the protease of the human immunodeficiency virus type 1 (HIV-1 using protease sequences collected for almost a decade from both treated and untreated patients, to understand how epistasis changes and how those changes impact the long-term evolvability of a protein. We use an information-theoretic proxy for epistasis that quantifies the co-variation between sites, and show that positive information is a necessary (but not sufficient condition that detects epistasis in most cases. We analyze the "fossils" of the evolutionary trajectories of the protein contained in the sequence data, and show that epistasis continues to enrich under strong selection, but not for proteins whose environment is unchanged. The increase in epistasis compensates for the information loss due to sequence variability brought about by treatment, and facilitates adaptation in the increasingly rugged fitness landscape of treatment. While epistasis is thought to enhance evolvability via valley-crossing early-on in adaptation, it can hinder adaptation later when the landscape has turned rugged. However, we find no evidence that the HIV-1 protease has reached its potential for evolution after 9 years of adapting to a drug environment that itself is constantly changing. We suggest that the mechanism of encoding new information into pairwise interactions is central to protein evolution not just in HIV-1 protease, but for any protein adapting to a changing

Acquisition, consolidation, reconsolidation, and extinction of eyelid conditioning responses require de novo protein synthesis.

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Inda, Mari Carmen; Delgado-García, José María; Carrión, Angel Manuel

2005-02-23

Memory, as measured by changes in an animal's behavior some time after learning, is a reflection of many processes. Here, using a trace paradigm, in mice we show that de novo protein synthesis is required for acquisition, consolidation, reconsolidation, and extinction of classically conditioned eyelid responses. Two critical periods of protein synthesis have been found: the first, during training, the blocking of which impaired acquisition; and the second, lasting the first 4 h after training, the blocking of which impaired consolidation. The process of reconsolidation was sensitive to protein synthesis inhibition if anisomycin was injected before or just after the reactivation session. Furthermore, extinction was also dependent on protein synthesis, following the same temporal course as that followed during acquisition and consolidation. This last fact reinforces the idea that extinction is an active learning process rather than a passive event of forgetting. Together, these findings demonstrate that all of the different stages of memory formation involved in the classical conditioning of eyelid responses are dependent on protein synthesis.

Leucine supplementation of a chronically restricted protein and energy diet enhances mTOR pathway activation but not muscle protein synthesis in neonatal pigs.

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Manjarín, Rodrigo; Columbus, Daniel A; Suryawan, Agus; Nguyen, Hanh V; Hernandez-García, Adriana D; Hoang, Nguyet-Minh; Fiorotto, Marta L; Davis, Teresa

2016-01-01

Suboptimal nutrient intake represents a limiting factor for growth and long-term survival of low-birth weight infants. The objective of this study was to determine if in neonates who can consume only 70 % of their protein and energy requirements for 8 days, enteral leucine supplementation will upregulate the mammalian target of rapamycin (mTOR) pathway in skeletal muscle, leading to an increase in protein synthesis and muscle anabolism. Nineteen 4-day-old piglets were fed by gastric tube 1 of 3 diets, containing (kg body weight(-1) · day(-1)) 16 g protein and 190 kcal (CON), 10.9 g protein and 132 kcal (R), or 10.8 g protein + 0.2 % leucine and 136 kcal (RL) at 4-h intervals for 8 days. On day 8, plasma AA and insulin levels were measured during 6 post-feeding intervals, and muscle protein synthesis rate and mTOR signaling proteins were determined at 120 min post-feeding. At 120 min, leucine was highest in RL (P protein synthesis, phosphorylation of S6 kinase (p-S6K1) and 4E-binding protein (p-4EBP1), and activation of eukaryotic initiation factor 4 complex (eIF4E · eIF4G). RL increased (P ≤ 0.01) p-S6K1, p-4EBP1 and eIF4E · eIF4G compared to R. In conclusion, when protein and energy intakes are restricted for 8 days, leucine supplementation increases muscle mTOR activation, but does not improve body weight gain or enhance skeletal muscle protein synthesis in neonatal pigs.

GluA2-dependent AMPA receptor endocytosis and the decay of early and late long-term potentiation: possible mechanisms for forgetting of short- and long-term memories.

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Hardt, Oliver; Nader, Karim; Wang, Yu-Tian

2014-01-05

The molecular processes involved in establishing long-term potentiation (LTP) have been characterized well, but the decay of early and late LTP (E-LTP and L-LTP) is poorly understood. We review recent advances in describing the mechanisms involved in maintaining LTP and homeostatic plasticity. We discuss how these phenomena could relate to processes that might underpin the loss of synaptic potentiation over time, and how they might contribute to the forgetting of short-term and long-term memories. We propose that homeostatic downscaling mediates the loss of E-LTP, and that metaplastic parameters determine the decay rate of L-LTP, while both processes require the activity-dependent removal of postsynaptic GluA2-containing AMPA receptors.

Dependency on de novo protein synthesis and proteomic changes during metamorphosis of the marine bryozoan Bugula neritina

KAUST Repository

Wong, Yue Him

2010-05-24

Background: Metamorphosis in the bryozoan Bugula neritina (Linne) includes an initial phase of rapid morphological rearrangement followed by a gradual phase of morphogenesis. We hypothesized that the first phase may be independent of de novo synthesis of proteins and, instead, involves post-translational modifications of existing proteins, providing a simple mechanism to quickly initiate metamorphosis. To test our hypothesis, we challenged B. neritina larvae with transcription and translation inhibitors. Furthermore, we employed 2D gel electrophoresis to characterize changes in the phosphoproteome and proteome during early metamorphosis. Differentially expressed proteins were identified by liquid chromatography tandem mass spectrometry and their gene expression patterns were profiled using semi-quantitative real time PCR.Results: When larvae were incubated with transcription and translation inhibitors, metamorphosis initiated through the first phase but did not complete. We found a significant down-regulation of 60 protein spots and the percentage of phosphoprotein spots decreased from 15% in the larval stage to12% during early metamorphosis. Two proteins--the mitochondrial processing peptidase beta subunit and severin--were abundantly expressed and phosphorylated in the larval stage, but down-regulated during metamorphosis. MPPbeta and severin were also down-regulated on the gene expression level.Conclusions: The initial morphogenetic changes that led to attachment of B. neritina did not depend on de novo protein synthesis, but the subsequent gradual morphogenesis did. This is the first time that the mitochondrial processing peptidase beta subunit or severin have been shown to be down-regulated on both gene and protein expression levels during the metamorphosis of B. neritina. Future studies employing immunohistochemistry to reveal the expression locality of these two proteins during metamorphosis should provide further evidence of the involvement of these two

Natural course of care dependency in residents of long-term care facilities: prospective follow-up study.

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Caljouw, Monique A A; Cools, Herman J M; Gussekloo, Jacobijn

2014-05-22

Insight in the natural course of care dependency of vulnerable older persons in long-term care facilities (LTCF) is essential to organize and optimize individual tailored care. We examined changes in care dependency in LTCF residents over two 6-month periods, explored the possible predictive factors of change and the effect of care dependency on mortality. A prospective follow-up study in 21 Dutch long-term care facilities. 890 LTCF residents, median age 84 (Interquartile range 79-88) years participated. At baseline, 6 and 12 months, care dependency was assessed by the nursing staff with the Care Dependency Scale (CDS), range 15-75 points. Since the median CDS score differed between men and women (47.5 vs. 43.0, P = 0.013), CDS groups (low, middle and high) were based on gender-specific 33% of CDS scores at baseline and 6 months. At baseline, the CDS groups differed in median length of stay on the ward, urine incontinence and dementia (all P dependency status, predicted an increase in care dependency over time. The majority of residents were stable in their care dependency status over two subsequent 6-month periods. Highly care dependent residents showed an increased mortality risk. Awareness of the natural course of care dependency is essential to residents and their formal and informal caregivers when considering therapeutic and end-of-life care options.

Improving protein disorder prediction by deep bidirectional long short-term memory recurrent neural networks.

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Hanson, Jack; Yang, Yuedong; Paliwal, Kuldip; Zhou, Yaoqi

2017-03-01

Capturing long-range interactions between structural but not sequence neighbors of proteins is a long-standing challenging problem in bioinformatics. Recently, long short-term memory (LSTM) networks have significantly improved the accuracy of speech and image classification problems by remembering useful past information in long sequential events. Here, we have implemented deep bidirectional LSTM recurrent neural networks in the problem of protein intrinsic disorder prediction. The new method, named SPOT-Disorder, has steadily improved over a similar method using a traditional, window-based neural network (SPINE-D) in all datasets tested without separate training on short and long disordered regions. Independent tests on four other datasets including the datasets from critical assessment of structure prediction (CASP) techniques and >10 000 annotated proteins from MobiDB, confirmed SPOT-Disorder as one of the best methods in disorder prediction. Moreover, initial studies indicate that the method is more accurate in predicting functional sites in disordered regions. These results highlight the usefulness combining LSTM with deep bidirectional recurrent neural networks in capturing non-local, long-range interactions for bioinformatics applications. SPOT-disorder is available as a web server and as a standalone program at: http://sparks-lab.org/server/SPOT-disorder/index.php . j.hanson@griffith.edu.au or yuedong.yang@griffith.edu.au or yaoqi.zhou@griffith.edu.au. Supplementary data is available at Bioinformatics online. © The Author 2016. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com

Jatropha curcas Protein Concentrate Stimulates Insulin Signaling, Lipogenesis, Protein Synthesis and the PKCα Pathway in Rat Liver.

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León-López, Liliana; Márquez-Mota, Claudia C; Velázquez-Villegas, Laura A; Gálvez-Mariscal, Amanda; Arrieta-Báez, Daniel; Dávila-Ortiz, Gloria; Tovar, Armando R; Torres, Nimbe

2015-09-01

Jatropha curcas is an oil seed plant that belongs to the Euphorbiaceae family. Nontoxic genotypes have been reported in Mexico. The purpose of the present work was to evaluate the effect of a Mexican variety of J. curcas protein concentrate (JCP) on weight gain, biochemical parameters, and the expression of genes and proteins involved in insulin signaling, lipogenesis, cholesterol and protein synthesis in rats. The results demonstrated that short-term consumption of JCP increased serum glucose, insulin, triglycerides and cholesterol levels as well as the expression of transcription factors involved in lipogenesis and cholesterol synthesis (SREBP-1 and LXRα). Moreover, there was an increase in insulin signaling mediated by Akt phosphorylation and mTOR. JCP also increased PKCα protein abundance and the activation of downstream signaling pathway targets such as the AP1 and NF-κB transcription factors typically activated by phorbol esters. These results suggested that phorbol esters are present in JCP, and that they could be involved in the activation of PKC which may be responsible for the high insulin secretion and consequently the activation of insulin-dependent pathways. Our data suggest that this Mexican Jatropha variety contains toxic compounds that produce negative metabolic effects which require caution when using in the applications of Jatropha-based products in medicine and nutrition.

Intrathecal injection of naked plasmid DNA provides long-term expression of secreted proteins.

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Hughes, Travis S; Langer, Stephen J; Johnson, Kirk W; Chavez, Raymond A; Watkins, Linda R; Milligan, Erin D; Leinwand, Leslie A

2009-01-01

Therapeutic benefit has been reported to result from intrathecal (i.t.) injection of transgene vectors, including naked DNA. However, most studies using naked DNA have measured only the transgene expression of intracellular proteins. Here we demonstrate that i.t. injection of naked DNA can result in long-term expression of secreted proteins. Plasmids expressing either secreted alkaline phosphatase (SEAP) or human interleukin-10 (hIL-10) were injected into the i.t. space in rats, and transgene products were repeatedly measured in the cerebrospinal fluid (CSF). Both SEAP and hIL-10 were maximal at 1 and 2 days after the injection and still detectable at 4 months. The utilization of a plasmid having two features that are hypothesized to increase gene expression (matrix attachment regions (MARs) and lack of CpG dinucleotides) resulted in a significant increase in gene expression. Reinjection of SEAP or hIL-10 plasmids after 4 months significantly increased protein levels at 1 and 14 days after the reinjection. SEAP was uniformly distributed between the DNA delivery site (approximately vertebral level T13) and the lumbar puncture site (L5/L6 inter-vertebral space), was reduced at the cisterna magna, and was detectable, though at much lower levels, in serum. These data suggest that naked DNA has the potential to be used as a therapeutic tool for applications that require long-term release of transgenes into the CSF.

Effect of heat stress on the pattern of protein synthesis in wheat endosperm

International Nuclear Information System (INIS)

Inwood, W.; Bernardin, J.

1990-01-01

The exposure of detached wheat heads (T. aestivum L. cv Cheyenne) to elevated temperatures resulted not only in the induction of a typical set of high and low molecular weight heat shock proteins (hsps), but also in a differential effect on the synthesis of wheat storage proteins in endosperm tissue when monitored by SDS PAGE of 35 S-labeled polypeptides. The synthesis of hsps in the endosperm had a rapid onset, reached a maximum rate within the first 2 hours at 40 degree C, and then steadily decreased during the next four hours. When heads were returned to 25 degree C after 3 hours at 40 degree C, hsp synthesis did not cease abruptly, but gradually declined over the next several hours. High molecular weight glutenin protein synthesis was drastically reduced with the same time course as heat shock protein synthesis was induced at 40 degree C. Conversely, the synthesis of gliadin proteins remained at a high level at 40 degree C. The synthesis rates for glutenin and gliadin proteins remained at low and high levels, respectively, for as long as the elevated temperature was maintained up to 7 hours

Activity dependent protein degradation is critical for the formation and stability of fear memory in the amygdala.

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Timothy J Jarome

Full Text Available Protein degradation through the ubiquitin-proteasome system [UPS] plays a critical role in some forms of synaptic plasticity. However, its role in memory formation in the amygdala, a site critical for the formation of fear memories, currently remains unknown. Here we provide the first evidence that protein degradation through the UPS is critically engaged at amygdala synapses during memory formation and retrieval. Fear conditioning results in NMDA-dependent increases in degradation-specific polyubiquitination in the amygdala, targeting proteins involved in translational control and synaptic structure and blocking the degradation of these proteins significantly impairs long-term memory. Furthermore, retrieval of fear memory results in a second wave of NMDA-dependent polyubiquitination that targets proteins involved in translational silencing and synaptic structure and is critical for memory updating following recall. These results indicate that UPS-mediated protein degradation is a major regulator of synaptic plasticity necessary for the formation and stability of long-term memories at amygdala synapses.

Increased mitochondrial energy efficiency in skeletal muscle after long-term fasting: its relevance to animal performance.

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Bourguignon, Aurore; Rameau, Anaïs; Toullec, Gaëlle; Romestaing, Caroline; Roussel, Damien

2017-07-01

In the final stage of fasting, skeletal muscle mass and protein content drastically decrease when the maintenance of efficient locomotor activity becomes crucial for animals to reactivate feeding behaviour and survive a very long period of starvation. As mitochondrial metabolism represents the main physiological link between the endogenous energy store and animal performance, the aim of this study was to determine how a very long, natural period of fasting affected skeletal muscle mitochondrial bioenergetics in king penguin ( Aptenodytes patagonicus ) chicks. Rates of mitochondrial oxidative phosphorylation were measured in pectoralis permeabilized fibres and isolated mitochondria. Mitochondrial ATP synthesis efficiency and the activities of respiratory chain complexes were measured in mitochondria isolated from pectoralis muscle. Results from long-term (4-5 months) naturally fasted chicks were compared with those from short-term (10 day) fasted birds. The respiratory activities of muscle fibres and isolated mitochondria were reduced by 60% and 45%, respectively, on average in long-term fasted chicks compared with short-term fasted birds. Oxidative capacity and mitochondrial content of pectoralis muscle were lowered by long-term fasting. Bioenergetic analysis of pectoralis muscle also revealed that mitochondria were, on average, 25% more energy efficient in the final stage of fasting (4-5 months) than after 10 days of fasting (short-term fasted birds). These results suggest that the strong reduction in respiratory capacity of pectoralis muscle was partly alleviated by increased mitochondrial ATP synthesis efficiency. Such oxidative phosphorylation optimization can impact animal performance, e.g. the metabolic cost of locomotion or the foraging efficiency. © 2017. Published by The Company of Biologists Ltd.

Acute myotube protein synthesis regulation by IL-6-related cytokines.

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Gao, Song; Durstine, J Larry; Koh, Ho-Jin; Carver, Wayne E; Frizzell, Norma; Carson, James A

2017-11-01

IL-6 and leukemia inhibitory factor (LIF), members of the IL-6 family of cytokines, play recognized paradoxical roles in skeletal muscle mass regulation, being associated with both growth and atrophy. Overload or muscle contractions can induce a transient increase in muscle IL-6 and LIF expression, which has a regulatory role in muscle hypertrophy. However, the cellular mechanisms involved in this regulation have not been completely identified. The induction of mammalian target of rapamycin complex 1 (mTORC1)-dependent myofiber protein synthesis is an established regulator of muscle hypertrophy, but the involvement of the IL-6 family of cytokines in this process is poorly understood. Therefore, we investigated the acute effects of IL-6 and LIF administration on mTORC1 signaling and protein synthesis in C2C12 myotubes. The role of glycoprotein 130 (gp130) receptor and downstream signaling pathways, including phosphoinositide 3-kinase (PI3K)-Akt-mTORC1 and signal transducer and activator of transcription 3 (STAT3)-suppressor of cytokine signaling 3 (SOCS3), was investigated by administration of specific siRNA or pharmaceutical inhibitors. Acute administration of IL-6 and LIF induced protein synthesis, which was accompanied by STAT3 activation, Akt-mTORC1 activation, and increased SOCS3 expression. This induction of protein synthesis was blocked by both gp130 siRNA knockdown and Akt inhibition. Interestingly, STAT3 inhibition or Akt downstream mTORC1 signaling inhibition did not fully block the IL-6 or LIF induction of protein synthesis. SOCS3 siRNA knockdown increased basal protein synthesis and extended the duration of the protein synthesis induction by IL-6 and LIF. These results demonstrate that either IL-6 or LIF can activate gp130-Akt signaling axis, which induces protein synthesis via mTORC1-independent mechanisms in cultured myotubes. However, IL-6- or LIF-induced SOCS3 negatively regulates the activation of myotube protein synthesis. Copyright © 2017 the

Synthesis of milligram quantities of proteins using a reconstituted in vitro protein synthesis system.

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Kazuta, Yasuaki; Matsuura, Tomoaki; Ichihashi, Norikazu; Yomo, Tetsuya

2014-11-01

In this study, the amount of protein synthesized using an in vitro protein synthesis system composed of only highly purified components (the PURE system) was optimized. By varying the concentrations of each system component, we determined the component concentrations that result in the synthesis of 0.38 mg/mL green fluorescent protein (GFP) in batch mode and 3.8 mg/mL GFP in dialysis mode. In dialysis mode, protein concentrations of 4.3 and 4.4 mg/mL were synthesized for dihydrofolate reductase and β-galactosidase, respectively. Using the optimized system, the synthesized protein represented 30% (w/w) of the total protein, which is comparable to the level of overexpressed protein in Escherichia coli cells. This optimized reconstituted in vitro protein synthesis system may potentially be useful for various applications, including in vitro directed evolution of proteins, artificial cell assembly, and protein structural studies. Copyright © 2014 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Effect of whey protein supplementation on long and short term appetite: A meta-analysis of randomized controlled trials.

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Mollahosseini, Mehdi; Shab-Bidar, Sakineh; Rahimi, Mohammad Hossein; Djafarian, Kurosh

2017-08-01

Specific components of dairy, such as whey proteins may have beneficial effects on body composition by suppressing appetite, although the findings of existing studies have been inconsistent. Therefore, a meta-analysis of randomized controlled trials was performed to investigate effect of whey protein supplementation on long and short term appetite. A systematic search was conducted to identify eligible publications. Means and SDs for hunger, fullness, satiety, desire to eat and prospective consumption of food, before and after intervention, were extracted and then composite appetite score (CAS) calculated. To pool data, either a fixed-effects model or a random-effects model and for assessing heterogeneity, Cochran's Q and I 2 tests were used. Eight publications met inclusion criteria that 5 records were on short term and 3 records on long term appetite. The meta-analysis showed a significant reduction in long term appetite by 4.13 mm in combined appetite score (CAS) (95% Confidence interval (CI): -6.57, -1.96; p = 0.001). No significant reduction in short term appetite was also seen (Mean difference (MD) = -0.39 95% CI = -2.07, 1.30; p = 0.653). Subgroup analyses by time showed that compared with carbohydrate, the reduction in appetite following consumption of whey consumption was not significant (MD = -0.39, 95% CI = -2.07, 1.3, p = 0.65, I 2  = 0.0%.)A significant reduction in prospective food consumption was seen (MD = -2.17, 95% CI = -3.86, -0.48). The results of our meta-analysis showed that whey protein may reduce the long and short term appetite, but our finding did not show any significant difference in appetite reduction between whey protein and carbohydrate in short duration. Copyright © 2017 European Society for Clinical Nutrition and Metabolism. Published by Elsevier Ltd. All rights reserved.

Stress within a Restricted Time Window Selectively Affects the Persistence of Long-Term Memory

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Fang, Qin; Chai, Ning; Zhao, Li-Yan; Xue, Yan-Xue; Luo, Yi-Xiao; Jian, Min; Han, Ying; Shi, Hai-Shui; Lu, Lin; Wu, Ping; Wang, Ji-Shi

2013-01-01

The effects of stress on emotional memory are distinct and depend on the stages of memory. Memory undergoes consolidation and reconsolidation after acquisition and retrieval, respectively. Stress facilitates the consolidation but disrupts the reconsolidation of emotional memory. Previous research on the effects of stress on memory have focused on long-term memory (LTM) formation (tested 24 h later), but the effects of stress on the persistence of LTM (tested at least 1 week later) are unclear. Recent findings indicated that the persistence of LTM requires late-phase protein synthesis in the dorsal hippocampus. The present study investigated the effect of stress (i.e., cold water stress) during the late phase after the acquisition and retrieval of contextual fear memory in rats. We found that stress and corticosterone administration during the late phase (12 h) after acquisition, referred to as late consolidation, selectively enhanced the persistence of LTM, whereas stress during the late phase (12 h) after retrieval, referred to as late reconsolidation, selectively disrupted the restabilized persistence of LTM. Moreover, the effects of stress on the persistence of LTM were blocked by the corticosterone synthesis inhibitor metyrapone, which was administered before stress, suggesting that the glucocorticoid system is involved in the effects of stress on the persistence of LTM. We conclude that stress within a restricted time window after acquisition or retrieval selectively affects the persistence of LTM and depends on the glucocorticoid system. PMID:23544051

An improved non-Markovian degradation model with long-term dependency and item-to-item uncertainty

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Xi, Xiaopeng; Chen, Maoyin; Zhang, Hanwen; Zhou, Donghua

2018-05-01

It is widely noted in the literature that the degradation should be simplified into a memoryless Markovian process for the purpose of predicting the remaining useful life (RUL). However, there actually exists the long-term dependency in the degradation processes of some industrial systems, including electromechanical equipments, oil tankers, and large blast furnaces. This implies the new degradation state depends not only on the current state, but also on the historical states. Such dynamic systems cannot be accurately described by traditional Markovian models. Here we present an improved non-Markovian degradation model with both the long-term dependency and the item-to-item uncertainty. As a typical non-stationary process with dependent increments, fractional Brownian motion (FBM) is utilized to simulate the fractal diffusion of practical degradations. The uncertainty among multiple items can be represented by a random variable of the drift. Based on this model, the unknown parameters are estimated through the maximum likelihood (ML) algorithm, while a closed-form solution to the RUL distribution is further derived using a weak convergence theorem. The practicability of the proposed model is fully verified by two real-world examples. The results demonstrate that the proposed method can effectively reduce the prediction error.

Signaling through cGMP-dependent protein kinase I in the amygdala is critical for auditory-cued fear memory and long-term potentiation.

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Paul, Cindy; Schöberl, Florian; Weinmeister, Pascal; Micale, Vincenzo; Wotjak, Carsten T; Hofmann, Franz; Kleppisch, Thomas

2008-12-24

Long-term potentiation (LTP) of inputs relaying sensory information from cortical and thalamic neurons to principal neurons in the lateral amygdala (LA) is thought to serve as a cellular mechanism for associative fear learning. Nitric oxide (NO), a messenger molecule widely implicated in synaptic plasticity and behavior, has been shown to enhance LTP in the LA as well as consolidation of associative fear memory. Additional evidence suggests that NO-induced enhancement of LTP and amygdala-dependent learning requires signaling through soluble guanylyl cyclase (sGC) and cGMP-dependent protein kinase (cGK). Mammals possess two genes for cGK: the prkg1 gene gives rise to the cGK type I isoforms, cGKIalpha and cGKIbeta, and the prkg2 gene encodes the cGK type II. Reportedly, both cGKI and cGKII are expressed in the amygdala, and cGKII is involved in controlling anxiety-like behavior. Because selective pharmacological tools for individual cGK isoforms are lacking, we used different knock-out mouse models to examine the function of cGKI and cGKII for LTP in the LA and pavlovian fear conditioning. We found robust expression of the cGKI specifically in the LA with cGKIbeta as the prevailing isoform. We further show a marked reduction of LTP at both thalamic and cortical inputs to the LA and a selective impairment of auditory-cued fear memory in cGKI-deficient mutants. In contrast, cGKII null mutants lack these phenotypes. Our data suggest a function of cGKI, likely the beta isoform, in the LA, supporting synaptic plasticity and consolidation of fear memory.

Bluetongue virus non-structural protein 1 is a positive regulator of viral protein synthesis

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Boyce Mark

2012-08-01

Full Text Available Abstract Background Bluetongue virus (BTV is a double-stranded RNA (dsRNA virus of the Reoviridae family, which encodes its genes in ten linear dsRNA segments. BTV mRNAs are synthesised by the viral RNA-dependent RNA polymerase (RdRp as exact plus sense copies of the genome segments. Infection of mammalian cells with BTV rapidly replaces cellular protein synthesis with viral protein synthesis, but the regulation of viral gene expression in the Orbivirus genus has not been investigated. Results Using an mRNA reporter system based on genome segment 10 of BTV fused with GFP we identify the protein characteristic of this genus, non-structural protein 1 (NS1 as sufficient to upregulate translation. The wider applicability of this phenomenon among the viral genes is demonstrated using the untranslated regions (UTRs of BTV genome segments flanking the quantifiable Renilla luciferase ORF in chimeric mRNAs. The UTRs of viral mRNAs are shown to be determinants of the amount of protein synthesised, with the pre-expression of NS1 increasing the quantity in each case. The increased expression induced by pre-expression of NS1 is confirmed in virus infected cells by generating a replicating virus which expresses the reporter fused with genome segment 10, using reverse genetics. Moreover, NS1-mediated upregulation of expression is restricted to mRNAs which lack the cellular 3′ poly(A sequence identifying the 3′ end as a necessary determinant in specifically increasing the translation of viral mRNA in the presence of cellular mRNA. Conclusions NS1 is identified as a positive regulator of viral protein synthesis. We propose a model of translational regulation where NS1 upregulates the synthesis of viral proteins, including itself, and creates a positive feedback loop of NS1 expression, which rapidly increases the expression of all the viral proteins. The efficient translation of viral reporter mRNAs among cellular mRNAs can account for the observed

Bluetongue virus non-structural protein 1 is a positive regulator of viral protein synthesis.

Science.gov (United States)

Boyce, Mark; Celma, Cristina C P; Roy, Polly

2012-08-29

Bluetongue virus (BTV) is a double-stranded RNA (dsRNA) virus of the Reoviridae family, which encodes its genes in ten linear dsRNA segments. BTV mRNAs are synthesised by the viral RNA-dependent RNA polymerase (RdRp) as exact plus sense copies of the genome segments. Infection of mammalian cells with BTV rapidly replaces cellular protein synthesis with viral protein synthesis, but the regulation of viral gene expression in the Orbivirus genus has not been investigated. Using an mRNA reporter system based on genome segment 10 of BTV fused with GFP we identify the protein characteristic of this genus, non-structural protein 1 (NS1) as sufficient to upregulate translation. The wider applicability of this phenomenon among the viral genes is demonstrated using the untranslated regions (UTRs) of BTV genome segments flanking the quantifiable Renilla luciferase ORF in chimeric mRNAs. The UTRs of viral mRNAs are shown to be determinants of the amount of protein synthesised, with the pre-expression of NS1 increasing the quantity in each case. The increased expression induced by pre-expression of NS1 is confirmed in virus infected cells by generating a replicating virus which expresses the reporter fused with genome segment 10, using reverse genetics. Moreover, NS1-mediated upregulation of expression is restricted to mRNAs which lack the cellular 3' poly(A) sequence identifying the 3' end as a necessary determinant in specifically increasing the translation of viral mRNA in the presence of cellular mRNA. NS1 is identified as a positive regulator of viral protein synthesis. We propose a model of translational regulation where NS1 upregulates the synthesis of viral proteins, including itself, and creates a positive feedback loop of NS1 expression, which rapidly increases the expression of all the viral proteins. The efficient translation of viral reporter mRNAs among cellular mRNAs can account for the observed replacement of cellular protein synthesis with viral protein

Involvement of translation and transcription processes into neurophysiological mechanisms of long-term memory reconsolidation.

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Kozyrev, S A; Nikitin, V P

2013-03-01

We studied the involvement of translation and transcription processes into behavioral and neuronal mechanisms of reconsolidation of the long-term memory of the conditioned taste aversion in edible snails. Injection of cycloheximide (an inhibitor of protein synthesis) to the snails in 48 h after training combined with subsequent reminder and presentation of the conditional stimulus resulted in the development of persistent amnesia and depression of the responses of the defensive behavior command neurons LPl1 and RPl1 to the conditional stimulus. Injection of mRNA synthesis inhibitors actinomycin D or DRB (5,6-dichloro-1-β-D-ribofuranosylbenzimidasole) in 48 h after conditioning with subsequent reminding procedure produced no effects on memory retention and on the responses of the command neurons to the conditional stimulus. The study suggests that the proteins translated from previously synthesized and stored mRNA were involved in the mechanisms of reconsolidation of the memory responsible for conditioned taste aversion.

Enhanced green fluorescent protein is a nearly ideal long-term expression tracer for hematopoietic stem cells, whereas DsRed-express fluorescent protein is not.

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Tao, Wen; Evans, Barbara-Graham; Yao, Jing; Cooper, Scott; Cornetta, Kenneth; Ballas, Christopher B; Hangoc, Giao; Broxmeyer, Hal E

2007-03-01

Validated gene transfer and expression tracers are essential for elucidating functions of mammalian genes. Here, we have determined the suitability and unintended side effects of enhanced green fluorescent protein (EGFP) and DsRed-Express fluorescent protein as expression tracers in long-term hematopoietic stem cells (HSCs). Retrovirally transduced mouse bone marrow cells expressing either EGFP or DsRed-Express in single or mixed dual-color cell populations were clearly discerned by flow cytometry and fluorescence microscopy. The results from in vivo competitive repopulation assays demonstrated that EGFP-expressing HSCs were maintained nearly throughout the lifespan of the transplanted mice and retained long-term multilineage repopulating potential. All mice assessed at 15 months post-transplantation were EGFP positive, and, on average, 24% total peripheral white blood cells expressed EGFP. Most EGFP-expressing recipient mice lived at least 22 months. In contrast, Discosoma sp. red fluorescent protein (DsRed)-expressing donor cells dramatically declined in transplant-recipient mice over time, particularly in the competitive setting, in which mixed EGFP- and DsRed-expressing cells were cotransplanted. Moreover, under in vitro culture condition favoring preservation of HSCs, purified EGFP-expressing cells grew robustly, whereas DsRed-expressing cells did not. Therefore, EGFP has no detectable deteriorative effects on HSCs, and is nearly an ideal long-term expression tracer for hematopoietic cells; however, DsRed-Express fluorescent protein is not suitable for these cells.

Modulation of protein synthesis by polyamines.

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Igarashi, Kazuei; Kashiwagi, Keiko

2015-03-01

Polyamines are ubiquitous small basic molecules that play important roles in cell growth and viability. Since polyamines mainly exist as a polyamine-RNA complex, we looked for proteins whose synthesis is preferentially stimulated by polyamines at the level of translation, and thus far identified 17 proteins in Escherichia coli and 6 proteins in eukaryotes. The mechanisms of polyamine stimulation of synthesis of these proteins were investigated. In addition, the role of eIF5A, containing hypusine formed from spermidine, on protein synthesis is described. These results clearly indicate that polyamines and eIF5A contribute to cell growth and viability through modulation of protein synthesis. © 2015 International Union of Biochemistry and Molecular Biology.

Effect of a long-term high-protein diet on survival, obesity development, and gut microbiota in mice

NARCIS (Netherlands)

Kiilerich, Pia; Myrmel, Lene Secher; Fjære, Even; Hao, Qin; Hugenholtz, Floor; Sonne, Si Brask; Derrien, Muriel; Pedersen, Lone Møller; Petersen, Rasmus Koefoed; Mortensen, Alicja; Licht, Tine Rask; Rømer, Maria Unni; Vogel, Ulla Birgitte; Waagbø, Linn Jeanette; Giallourou, Natasa; Feng, Qiang; Xiao, Liang; Liu, Chuan; Liaset, Bjørn; Kleerebezem, Michiel; Wang, Jun; Madsen, Lise; Kristiansen, Karsten

2016-01-01

Female C57BL/6J mice were fed a regular low-fat diet or high-fat diets combined with either high or low protein-to-sucrose ratios during their entire lifespan to examine the long-term effects on obesity development, gut microbiota, and survival. Intake of a high-fat diet with a low protein/sucrose

Effect of a long-term high-protein diet on survival, obesity development, and gut microbiota in mice.

Science.gov (United States)

Kiilerich, Pia; Myrmel, Lene Secher; Fjære, Even; Hao, Qin; Hugenholtz, Floor; Sonne, Si Brask; Derrien, Muriel; Pedersen, Lone Møller; Petersen, Rasmus Koefoed; Mortensen, Alicja; Licht, Tine Rask; Rømer, Maria Unni; Vogel, Ulla Birgitte; Waagbø, Linn Jeanette; Giallourou, Natasa; Feng, Qiang; Xiao, Liang; Liu, Chuan; Liaset, Bjørn; Kleerebezem, Michiel; Wang, Jun; Madsen, Lise; Kristiansen, Karsten

2016-06-01

Female C57BL/6J mice were fed a regular low-fat diet or high-fat diets combined with either high or low protein-to-sucrose ratios during their entire lifespan to examine the long-term effects on obesity development, gut microbiota, and survival. Intake of a high-fat diet with a low protein/sucrose ratio precipitated obesity and reduced survival relative to mice fed a low-fat diet. By contrast, intake of a high-fat diet with a high protein/sucrose ratio attenuated lifelong weight gain and adipose tissue expansion, and survival was not significantly altered relative to low-fat-fed mice. Our findings support the notion that reduced survival in response to high-fat/high-sucrose feeding is linked to obesity development. Digital gene expression analyses, further validated by qPCR, demonstrated that the protein/sucrose ratio modulated global gene expression over time in liver and adipose tissue, affecting pathways related to metabolism and inflammation. Analysis of fecal bacterial DNA using the Mouse Intestinal Tract Chip revealed significant changes in the composition of the gut microbiota in relation to host age and dietary fat content, but not the protein/sucrose ratio. Accordingly, dietary fat rather than the protein/sucrose ratio or adiposity is a major driver shaping the gut microbiota, whereas the effect of a high-fat diet on survival is dependent on the protein/sucrose ratio. Copyright © 2016 the American Physiological Society.

Leucine-Enriched Essential Amino Acids Augment Mixed Protein Synthesis, But Not Collagen Protein Synthesis, in Rat Skeletal Muscle after Downhill Running

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Kato, Hiroyuki; Suzuki, Hiromi; Inoue, Yoshiko; Suzuki, Katsuya; Kobayashi, Hisamine

2016-01-01

Mixed and collagen protein synthesis is elevated for as many as 3 days following exercise. Immediately after exercise, enhanced amino acid availability increases synthesis of mixed muscle protein, but not muscle collagen protein. However, the potential for synergic effects of amino acid ingestion with exercise on both mixed and collagen protein synthesis remains unclear. We investigated muscle collagen protein synthesis in rats following post-exercise ingestion of leucine-enriched essential amino acids. We determined fractional protein synthesis rates (FSR) at different time points following exercise. Mixed protein and collagen protein FSRs in skeletal muscle were determined by measuring protein-bound enrichments of hydroxyproline and proline, and by measuring the intracellular enrichment of proline, using injections of flooding d3-proline doses. A leucine-enriched mixture of essential amino acids (or distilled water as a control) was administrated 30 min or 1 day post-exercise. The collagen protein synthesis in the vastus lateralis was elevated for 2 days after exercise. Although amino acid administration did not increase muscle collagen protein synthesis, it did lead to augmented mixed muscle protein synthesis 1 day following exercise. Thus, contrary to the regulation of mixed muscle protein synthesis, muscle collagen protein synthesis is not affected by amino acid availability after damage-inducing exercise. PMID:27367725

Leucine-Enriched Essential Amino Acids Augment Mixed Protein Synthesis, But Not Collagen Protein Synthesis, in Rat Skeletal Muscle after Downhill Running

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Hiroyuki Kato

2016-06-01

Full Text Available Mixed and collagen protein synthesis is elevated for as many as 3 days following exercise. Immediately after exercise, enhanced amino acid availability increases synthesis of mixed muscle protein, but not muscle collagen protein. However, the potential for synergic effects of amino acid ingestion with exercise on both mixed and collagen protein synthesis remains unclear. We investigated muscle collagen protein synthesis in rats following post-exercise ingestion of leucine-enriched essential amino acids. We determined fractional protein synthesis rates (FSR at different time points following exercise. Mixed protein and collagen protein FSRs in skeletal muscle were determined by measuring protein-bound enrichments of hydroxyproline and proline, and by measuring the intracellular enrichment of proline, using injections of flooding d3-proline doses. A leucine-enriched mixture of essential amino acids (or distilled water as a control was administrated 30 min or 1 day post-exercise. The collagen protein synthesis in the vastus lateralis was elevated for 2 days after exercise. Although amino acid administration did not increase muscle collagen protein synthesis, it did lead to augmented mixed muscle protein synthesis 1 day following exercise. Thus, contrary to the regulation of mixed muscle protein synthesis, muscle collagen protein synthesis is not affected by amino acid availability after damage-inducing exercise.

Long-Term Memory Search across the Visual Brain

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Milan Fedurco

2012-01-01

Full Text Available Signal transmission from the human retina to visual cortex and connectivity of visual brain areas are relatively well understood. How specific visual perceptions transform into corresponding long-term memories remains unknown. Here, I will review recent Blood Oxygenation Level-Dependent functional Magnetic Resonance Imaging (BOLD fMRI in humans together with molecular biology studies (animal models aiming to understand how the retinal image gets transformed into so-called visual (retinotropic maps. The broken object paradigm has been chosen in order to illustrate the complexity of multisensory perception of simple objects subject to visual —rather than semantic— type of memory encoding. The author explores how amygdala projections to the visual cortex affect the memory formation and proposes the choice of experimental techniques needed to explain our massive visual memory capacity. Maintenance of the visual long-term memories is suggested to require recycling of GluR2-containing α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors (AMPAR and β2-adrenoreceptors at the postsynaptic membrane, which critically depends on the catalytic activity of the N-ethylmaleimide-sensitive factor (NSF and protein kinase PKMζ.

Hyaline cartilage regeneration by combined therapy of microfracture and long-term bone morphogenetic protein-2 delivery.

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Yang, Hee Seok; La, Wan-Geun; Bhang, Suk Ho; Kim, Hak-Jun; Im, Gun-Il; Lee, Haeshin; Park, Jung-Ho; Kim, Byung-Soo

2011-07-01

Microfracture of cartilage induces migration of bone-marrow-derived mesenchymal stem cells. However, this treatment often results in fibrocartilage regeneration. Growth factors such as bone morphogenetic protein (BMP)-2 induce the differentiation of bone-marrow-derived mesenchymal stem cells into chondrocytes, which can be used for hyaline cartilage regeneration. Here, we tested the hypothesis that long-term delivery of BMP-2 to cartilage defects subjected to microfracture results in regeneration of high-quality hyaline-like cartilage, as opposed to short-term delivery of BMP-2 or no BMP-2 delivery. Heparin-conjugated fibrin (HCF) and normal fibrin were used as carriers for the long- and short-term delivery of BMP-2, respectively. Rabbit articular cartilage defects were treated with microfracture combined with one of the following: no treatment, fibrin, short-term delivery of BMP-2, HCF, or long-term delivery of BMP-2. Eight weeks after treatment, histological analysis revealed that the long-term delivery of BMP-2 group (microfracture + HCF + BMP-2) showed the most staining with alcian blue. A biochemical assay, real-time polymerase chain reaction assay and Western blot analysis all revealed that the long-term delivery of BMP-2 group had the highest glucosaminoglycan content as well as the highest expression level of collagen type II. Taken together, the long-term delivery of BMP-2 to cartilage defects subjected to microfracture resulted in regeneration of hyaline-like cartilage, as opposed to short-term delivery or no BMP-2 delivery. Therefore, this method could be more convenient for hyaline cartilage regeneration than autologous chondrocyte implantation due to its less invasive nature and lack of cell implantation.

N-acetylcysteine stimulates protein synthesis in enterocytes independently of glutathione synthesis.

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Yi, Dan; Hou, Yongqing; Wang, Lei; Long, Minhui; Hu, Shengdi; Mei, Huimin; Yan, Liqiong; Hu, Chien-An Andy; Wu, Guoyao

2016-02-01

Dietary supplementation with N-acetylcysteine (NAC) has been reported to improve intestinal health and treat gastrointestinal diseases. However, the underlying mechanisms are not fully understood. According to previous reports, NAC was thought to exert its effect through glutathione synthesis. This study tested the hypothesis that NAC enhances enterocyte growth and protein synthesis independently of cellular glutathione synthesis. Intestinal porcine epithelial cells were cultured for 3 days in Dulbecco's modified Eagle medium containing 0 or 100 μM NAC. To determine a possible role for GSH (the reduced form of glutathione) in mediating the effect of NAC on cell growth and protein synthesis, additional experiments were conducted using culture medium containing 100 μM GSH, 100 μM GSH ethyl ester (GSHee), diethylmaleate (a GSH-depletion agent; 10 μM), or a GSH-synthesis inhibitor (buthionine sulfoximine, BSO; 20 μM). NAC increased cell proliferation, GSH concentration, and protein synthesis, while inhibiting proteolysis. GSHee enhanced cell proliferation and GSH concentration without affecting protein synthesis but inhibited proteolysis. Conversely, BSO or diethylmaleate reduced cell proliferation and GSH concentration without affecting protein synthesis, while promoting protein degradation. At the signaling level, NAC augmented the protein abundance of total mTOR, phosphorylated mTOR, and phosphorylated 70S6 kinase as well as mRNA levels for mTOR and p70S6 kinase in IPEC-1 cells. Collectively, these results indicate that NAC upregulates expression of mTOR signaling proteins to stimulate protein synthesis in enterocytes independently of GSH generation. Our findings provide a hitherto unrecognized biochemical mechanism for beneficial effects of NAC in intestinal cells.

Activation of protein kinase C inhibits synthesis and release of decidual prolactin

International Nuclear Information System (INIS)

Harman, I.; Costello, A.; Ganong, B.; Bell, R.M.; Handwerger, S.

1986-01-01

Activation of calcium-activated, phospholipid-dependent protein kinase C by diacylglycerol and phorbol esters has been shown to mediate release of hormones in many systems. To determine whether protein kinase C activation is also involved in the regulation of prolactin release from human decidual, the authors have examined the effects of various acylglycerols and phorbol esters on the synthesis and release of prolactin from cultured human decidual cells. sn-1,2-Dioctanolyglycerol (diC 8 ), which is known to stimulate protein kinase C in other systems, inhibited prolactin release in a dose-dependent manner with maximal inhibition of 53.1% at 100 μM. Diolein (100 μM), which also stimulates protein kinase C activity in some systems, inhibited prolactin release by 21.3%. Phorbol 12-myristate 13-acetate (PMA), phorbol 12,13-didecanoate, and 4β-phorbol 12,13-dibutyrate, which activate protein kinase C in other systems, also inhibited the release of prolactin, which the protein kinase C inactivate 4α-phorbol-12,13-didecanoate was without effect. The inhibition of prolactin release was secondary to a decrease in prolactin synthesis. Although diC 8 and PMA inhibited the synthesis and release of prolactin, these agents had no effect on the synthesis or release of trichloroacetic acid-precipitable [ 35 S]methionine-labeled decidual proteins and did not cause the release of the cytosolic enzymes lactic dehydrogenase and alkaline phosphatase. DiC 8 and PMA stimulates the specific activity of protein kinase C in decidual tissue by 14.6 and 14.0-fold, respectively. The inhibition of the synthesis and release of prolactin by diC 8 and phorbol esters strongly implicates protein kinase C in the regulation of the production and release of prolactin from the decidua

Inhibition of protein synthesis but not β-adrenergic receptors blocks reconsolidation of a cocaine-associated cue memory

OpenAIRE

Dunbar, Amber B.; Taylor, Jane R.

2016-01-01

Previously consolidated memories have the potential to enter a state of lability upon memory recall, during which time the memory can be altered before undergoing an additional consolidation-like process and being stored again as a long-term memory. Blocking reconsolidation of aberrant memories has been proposed as a potential treatment for psychiatric disorders including addiction. Here we investigated of the effect of systemically administering the protein synthesis inhibitor cycloheximide ...

Protein intake does not increase vastus lateralis muscle protein synthesis during cycling

DEFF Research Database (Denmark)

Hulston, CJ; Wolsk, Emil; Grøndahl, Thomas Sahl

2011-01-01

PURPOSE: This study aimed to investigate the effect of protein ingestion on leg protein turnover and vastus lateralis muscle protein synthesis during bicycle exercise and recovery. METHODS: Eight healthy males participated in two experiments in which they ingested either a carbohydrate solution...... sampling, and blood flow measurements. Muscle protein synthesis was calculated from the incorporation of l-[ring-C6]phenylalanine into protein. RESULTS: Consuming protein during exercise increased leg protein synthesis and decreased net leg protein breakdown; however, protein ingestion did not increase...... protein synthesis within the highly active vastus lateralis muscle (0.029%·h(-1), ± 0.004%·h(-1), and 0.030%·h(-1), ± 0.003%·h(-1), in CHO and CHO + P, respectively; P = 0.88). In contrast, consuming protein, during exercise and recovery, increased postexercise vastus lateralis muscle protein synthesis...

Noncovalent synthesis of protein dendrimers

NARCIS (Netherlands)

Lempens, E.H.M.; Baal, van I.; Dongen, van J.L.J.; Hackeng, T.M.; Merkx, M.; Meijer, E.W.

2009-01-01

The covalent synthesis of complex biomolecular systems such as multivalent protein dendrimers often proceeds with low efficiency, thereby making alternative strategies based on noncovalent chemistry of high interest. Here, the synthesis of protein dendrimers using a strong but noncovalent

Involvement of protein kinase Mζ in the maintenance of long-term memory for taste aversion learning in young chicks.

Science.gov (United States)

Tiunova, A A; Bezryadnov, D V; Anokhin, K V

2015-03-01

The effects of an inhibitor of protein kinase Mζ on long-term memory were studied using the model of taste aversion in newborn chicks. Memory was impaired by intracerebral injection of 10 or 20 nmol of ζ-inhibiting peptide 24 h after training. Memory impairment was found 2 h after peptide administration, and repeated examination 24 h after treatment showed no recovery. Memory impairment was not observed 24 h after inhibitor administration if the testing 2 h after treatment was not performed. The results indicate the contribution of protein kinase Mζ in the maintenance of long-term memory in the avian brain. These data confirm the hypothesis of several authors that inhibition of protein kinase Mζ does not abolish memory, but rather interacts with processes of memory retrieval and/or reconsolidation.

Protein targeting to glycogen is a master regulator of glycogen synthesis in astrocytes

KAUST Repository

Ruchti, E.

2016-10-08

The storage and use of glycogen, the main energy reserve in the brain, is a metabolic feature of astrocytes. Glycogen synthesis is regulated by Protein Targeting to Glycogen (PTG), a member of specific glycogen-binding subunits of protein phosphatase-1 (PPP1). It positively regulates glycogen synthesis through de-phosphorylation of both glycogen synthase (activation) and glycogen phosphorylase (inactivation). In cultured astrocytes, PTG mRNA levels were previously shown to be enhanced by the neurotransmitter noradrenaline. To achieve further insight into the role of PTG in the regulation of astrocytic glycogen, its levels of expression were manipulated in primary cultures of mouse cortical astrocytes using adenovirus-mediated overexpression of tagged-PTG or siRNA to downregulate its expression. Infection of astrocytes with adenovirus led to a strong increase in PTG expression and was associated with massive glycogen accumulation (>100 fold), demonstrating that increased PTG expression is sufficient to induce glycogen synthesis and accumulation. In contrast, siRNA-mediated downregulation of PTG resulted in a 2-fold decrease in glycogen levels. Interestingly, PTG downregulation strongly impaired long-term astrocytic glycogen synthesis induced by insulin or noradrenaline. Finally, these effects of PTG downregulation on glycogen metabolism could also be observed in cultured astrocytes isolated from PTG-KO mice. Collectively, these observations point to a major role of PTG in the regulation of glycogen synthesis in astrocytes and indicate that conditions leading to changes in PTG expression will directly impact glycogen levels in this cell type.

Stress and glucocorticoid receptor-dependent mechanisms in long-term memory: from adaptive responses to psychopathologies.

Science.gov (United States)

Finsterwald, Charles; Alberini, Cristina M

2014-07-01

strong long-term memories because the activation of hippocampal GRs after learning is coupled to the recruitment of the growth and pro-survival BDNF/cAMP response element-binding protein (CREB) pathway, which is well-know to be a general mechanism required for long-term memory formation. We will then speculate about how these results may explain the negative effects of traumatic or chronic stress on memory and cognitive functions. Copyright © 2013 Elsevier Inc. All rights reserved.

Stress and glucocorticoid receptor-dependent mechanisms in long-term memory: from adaptive responses to psychopathologies

Science.gov (United States)

Finsterwald, Charles; Alberini, Cristina M.

2013-01-01

formation of strong long-term memories because the activation of hippocampal GRs after learning is coupled to the recruitment of the growth and pro-survival BDNF/cAMP response element-binding protein (CREB) pathway, which is well-know to be a general mechanism required for long-term memory formation. We will then speculate about how these results may explain the negative effects of traumatic or chronic stress on memory and cognitive functions. PMID:24113652

The Womanly World of Long Term Care: The Plight of the Long Term Care Worker. Gray Paper.

Science.gov (United States)

Older Women's League, Washington, DC.

Long-term care workers (those who are paid to provide custodial care for long-term patients in nursing homes or at home) must care for a growing number of increasingly disabled or dependent persons. They are working for agencies and institutions under growing pressure to increase productivity. They face new training and competency requirements,…

The Gcn4 transcription factor reduces protein synthesis capacity and extends yeast lifespan.

Science.gov (United States)

Mittal, Nitish; Guimaraes, Joao C; Gross, Thomas; Schmidt, Alexander; Vina-Vilaseca, Arnau; Nedialkova, Danny D; Aeschimann, Florian; Leidel, Sebastian A; Spang, Anne; Zavolan, Mihaela

2017-09-06

In Saccharomyces cerevisiae, deletion of large ribosomal subunit protein-encoding genes increases the replicative lifespan in a Gcn4-dependent manner. However, how Gcn4, a key transcriptional activator of amino acid biosynthesis genes, increases lifespan, is unknown. Here we show that Gcn4 acts as a repressor of protein synthesis. By analyzing the messenger RNA and protein abundance, ribosome occupancy and protein synthesis rate in various yeast strains, we demonstrate that Gcn4 is sufficient to reduce protein synthesis and increase yeast lifespan. Chromatin immunoprecipitation reveals Gcn4 binding not only at genes that are activated, but also at genes, some encoding ribosomal proteins, that are repressed upon Gcn4 overexpression. The promoters of repressed genes contain Rap1 binding motifs. Our data suggest that Gcn4 is a central regulator of protein synthesis under multiple perturbations, including ribosomal protein gene deletions, calorie restriction, and rapamycin treatment, and provide an explanation for its role in longevity and stress response.The transcription factor Gcn4 is known to regulate yeast amino acid synthesis. Here, the authors show that Gcn4 also acts as a repressor of protein biosynthesis in a range of conditions that enhance yeast lifespan, such as ribosomal protein knockout, calorie restriction or mTOR inhibition.

Labeling of hepatic glycogen after short- and long-term stimulation of glycogen synthesis in rats injected with 3H-galactose

International Nuclear Information System (INIS)

Michaels, J.E.; Garfield, S.A.; Hung, J.T.; Cardell, R.R. Jr.

1990-01-01

The effects of short- and long-term stimulation of glycogen synthesis elicited by dexamethasone were studied by light (LM) and electron (EM) microscopic radioautography (RAG) and biochemical analysis. Adrenalectomized rats were fasted overnight and pretreated for short- (3 hr) or long-term (14 hr) periods with dexamethasone prior to intravenous injection of tracer doses of 3H-galactose. Analysis of LM-RAGs from short-term rats revealed that about equal percentages (44%) of hepatocytes became heavily or lightly labeled 1 hr after labeling. The percentage of heavily labeled cells increased slightly 6 hr after labeling, and unlabeled glycogen became apparent in some hepatocytes. The percentage of heavily labeled cells had decreased somewhat 12 hr after labeling, and more unlabeled glycogen was evident. In the long-term rats 1 hr after labeling, a higher percentage of heavily labeled cells (76%) was observed compared to short-term rats, and most glycogen was labeled. In spite of the high amount of labeling seen initially, the percentage of heavily labeled hepatocytes had decreased considerably to 55% by 12 hr after injection; and sparsely labeled and unlabeled glycogen was prevalent. The EM-RAGs of both short- and long-term rats were similar. Silver grains were associated with glycogen patches 1 hr after labeling; 12 hr after labeling, the glycogen patches had enlarged; and label, where present, was dispersed over the enlarged glycogen clumps. Analysis of DPM/mg tissue corroborated the observed decrease in label 12 hr after administration in the long-term animals. The loss of label observed 12 hr after injection in the long-term pretreated rats suggests that turnover of glycogen occurred during this interval despite the net accumulation of glycogen that was visible morphologically and evident from biochemical measurement

Phrenic motor neuron TrkB expression is necessary for acute intermittent hypoxia-induced phrenic long-term facilitation

OpenAIRE

Dale, Erica A.; Fields, Daryl P.; Devinney, Michael J.; Mitchell, Gordon S.

2016-01-01

Phrenic long-term facilitation (pLTF) is a form of hypoxia-induced spinal respiratory motor plasticity that requires new synthesis of brain derived neurotrophic factor (BDNF) and activation of its high-affinity receptor, tropomyosin receptor kinase B (TrkB). Since the cellular location of relevant TrkB receptors is not known, we utilized intrapleural siRNA injections to selectively knock down TrkB receptor protein within phrenic motor neurons. TrkB receptors within phrenic motor neurons are n...

Sleep facilitates long-term face adaptation

OpenAIRE

Ditye, Thomas; Javadi, Amir Homayoun; Carbon, Claus-Christian; Walsh, Vincent

2013-01-01

Adaptation is an automatic neural mechanism supporting the optimization of visual processing on the basis of previous experiences. While the short-term effects of adaptation on behaviour and physiology have been studied extensively, perceptual long-term changes associated with adaptation are still poorly understood. Here, we show that the integration of adaptation-dependent long-term shifts in neural function is facilitated by sleep. Perceptual shifts induced by adaptation to a distorted imag...

Myostatin inhibits eEF2K-eEF2 by regulating AMPK to suppress protein synthesis.

Science.gov (United States)

Deng, Zhao; Luo, Pei; Lai, Wen; Song, Tongxing; Peng, Jian; Wei, Hong-Kui

2017-12-09

Growth of skeletal muscle is dependent on the protein synthesis, and the rate of protein synthesis is mainly regulated in the stage of translation initiation and elongation. Myostatin, a member of the transforming growth factor-β (TGF-β) superfamily, is a negative regulator of protein synthesis. C2C12 myotubes was incubated with 0, 0.01, 0.1, 1, 2, 3 μg/mL myostatin recombinant protein, and then we detected the rates of protein synthesis by the method of SUnSET. We found that high concentrations of myostatin (2 and 3 μg/mL) inhibited protein synthesis by blocking mTOR and eEF2K-eEF2 pathway, while low concentration of myostatin (0.01, 0.1 and 1 μg/mL) regulated eEF2K-eEF2 pathway activity to block protein synthesis without affected mTOR pathway, and myostatin inhibited eEF2K-eEF2 pathway through regulating AMPK pathway to suppress protein synthesis. It provided a new mechanism for myostatin regulating protein synthesis and treating muscle atrophy. Copyright © 2017. Published by Elsevier Inc.

Effects of Long-Term Protein Restriction on Meat Quality, Muscle Amino Acids, and Amino Acid Transporters in Pigs.

Science.gov (United States)

Yin, Jie; Li, Yuying; Zhu, Xiaotong; Han, Hui; Ren, Wenkai; Chen, Shuai; Bin, Peng; Liu, Gang; Huang, Xingguo; Fang, Rejun; Wang, Bin; Wang, Kai; Sun, Liping; Li, Tiejun; Yin, Yulong

2017-10-25

This study aimed to investigate the long-term effects of protein restriction from piglets to finishing pigs for 16 weeks on meat quality, muscle amino acids, and amino acid transporters. Thirty-nine piglets were randomly divided into three groups: a control (20-18-16% crude protein, CP) and two protein restricted groups (17-15-13% CP and 14-12-10% CP). The results showed that severe protein restriction (14-12-10% CP) inhibited feed intake and body weight, while moderate protein restriction (17-15-13% CP) had little effect on growth performance in pigs. Meat quality (i.e., pH, color traits, marbling, water-holding capacity, and shearing force) were tested, and the results exhibited that 14-12-10% CP treatment markedly improved muscle marbling score and increased yellowness (b*). pH value (45 min) was significantly higher in 17-15-13% CP group than that in other groups. In addition, protein restriction reduced muscle histone, arginine, valine, and isoleucine abundances and enhanced glycine and lysine concentrations compared with the control group, while the RT-PCR results showed that protein restriction downregulated amino acids transporters. Mechanistic target of rapamycin (mTOR) signaling pathway was inactivated in the moderate protein restricted group (17-15-13% CP), while severe protein restriction with dietary 14-12-10% CP markedly enhanced mTOR phosphorylation. In conclusion, long-term protein restriction affected meat quality and muscle amino acid metabolism in pigs, which might be associated with mTOR signaling pathway.

Leucine stimulation of skeletal muscle protein synthesis

International Nuclear Information System (INIS)

Layman, D.K.; Grogan, C.K.

1986-01-01

Previous work in this laboratory has demonstrated a stimulatory effect of leucine on skeletal muscle protein synthesis measured in vitro during catabolic conditions. Studies in other laboratories have consistently found this effect in diaphragm muscle, however, studies examining effects on nitrogen balance or with in vivo protein synthesis in skeletal muscle are equivocal. This experiment was designed to determine the potential of leucine to stimulate skeletal muscle protein synthesis in vivo. Male Sprague-Dawley rats weighing 200 g were fasted for 12 hrs, anesthetized, a jugular cannula inserted, and protein synthesis measured using a primed continuous infusion of 14 C-tyrosine. A plateau in specific activity was reached after 30 to 60 min and maintained for 3 hrs. The leucine dose consisted of a 240 umole priming dose followed by a continuous infusion of 160 umoles/hr. Leucine infusion stimulated protein synthesis in the soleus muscle (28%) and in the red (28%) and white portions (12%) of the gastrocnemius muscle compared with controls infused with only tyrosine. The increased rates of protein synthesis were due to increased incorporation of tyrosine into protein and to decreased specific activity of the free tyrosine pool. These data indicate that infusion of leucine has the potential to stimulate in vivo protein synthesis in skeletal muscles

Problem-Solving Test: The Mechanism of Protein Synthesis

Science.gov (United States)

Szeberenyi, Jozsef

2009-01-01

Terms to be familiar with before you start to solve the test: protein synthesis, ribosomes, amino acids, peptides, peptide bond, polypeptide chain, N- and C-terminus, hemoglobin, [alpha]- and [beta]-globin chains, radioactive labeling, [[to the third power]H] and [[to the fourteenth power]C]leucine, cytosol, differential centrifugation, density…

Cell-specific monitoring of protein synthesis in vivo.

Directory of Open Access Journals (Sweden)

Nikos Kourtis

Full Text Available Analysis of general and specific protein synthesis provides important information, relevant to cellular physiology and function. However, existing methodologies, involving metabolic labelling by incorporation of radioactive amino acids into nascent polypeptides, cannot be applied to monitor protein synthesis in specific cells or tissues, in live specimens. We have developed a novel approach for monitoring protein synthesis in specific cells or tissues, in vivo. Fluorescent reporter proteins such as GFP are expressed in specific cells and tissues of interest or throughout animals using appropriate promoters. Protein synthesis rates are assessed by following fluorescence recovery after partial photobleaching of the fluorophore at targeted sites. We evaluate the method by examining protein synthesis rates in diverse cell types of live, wild type or mRNA translation-defective Caenorhabditis elegans animals. Because it is non-invasive, our approach allows monitoring of protein synthesis in single cells or tissues with intrinsically different protein synthesis rates. Furthermore, it can be readily implemented in other organisms or cell culture systems.

Protein synthesis in the growing rat lung

International Nuclear Information System (INIS)

Kelley, J.; Chrin, L.

1986-01-01

Developmental control of protein synthesis in the postnatal growth of the lung has not been systematically studied. In male Fischer 344 rats, lung growth continues linearly as a function of body weight (from 75 to 450 g body weight). To study total protein synthesis in lungs of growing rats, we used the technique of constant intravenous infusion of tritiated leucine, an essential amino acid. Lungs of sacrificed animals were used to determine the leucine incorporation rate into newly synthesized protein. The specific radioactivity of the leucine associated with tRNA extracted from the same lungs served as an absolute index of the precursor leucine pool used for lung protein synthesis. On the basis of these measurements, we were able to calculate the fractional synthesis rate (the proportion of total protein destroyed and replaced each day) of pulmonary proteins for each rat. Under the conditions of isotope infusion, leucyl-tRNA very rapidly equilibrates with free leucine of the plasma and of the extracellular space of the lung. Infusions lasting 30 minutes or less yielded linear rates of protein synthesis without evidence of contamination of lung proteins by newly labeled intravascular albumin. The fractional synthesis rate is considerably higher in juvenile animals (55% per day) than in adult rats (20% per day). After approximately 12 weeks of age, the fractional synthesis rate remains extremely constant in spite of continued slow growth of the lung. It is apparent from these data that in both young and adult rats the bulk of total protein synthesis is devoted to rapidly turning over proteins and that less than 4 percent of newly made protein is committed to tissue growth

SINEUPs are modular antisense long-non coding RNAs that increase synthesis of target proteins in cells

Directory of Open Access Journals (Sweden)

Silvia eZucchelli

2015-05-01

Full Text Available Despite recent efforts in discovering novel long non-coding RNAs (lncRNAs and unveiling their functions in a wide range of biological processes their applications as biotechnological or therapeutic tools are still at their infancy. We have recently shown that AS Uchl1, a natural lncRNA antisense to the Parkinson’s disease-associated gene Ubiquitin carboxyl-terminal esterase L1 (Uchl1, is able to increase UchL1 protein synthesis at post-transcriptional level. Its activity requires two RNA elements: an embedded inverted SINEB2 sequence to increase translation and the overlapping region to target its sense mRNA. This functional organization is shared with several mouse lncRNAs antisense to protein coding genes. The potential use of AS Uchl1-derived lncRNAs as enhancers of target mRNA translation remains unexplored. Here we define AS Uchl1 as the representative member of a new functional class of natural and synthetic antisense lncRNAs that activate translation. We named this class of RNAs SINEUPs for their requirement of the inverted SINEB2 sequence to UP-regulate translation in a gene-specific manner. The overlapping region is indicated as the Binding Doman (BD while the embedded inverted SINEB2 element is the Effector Domain (ED. By swapping BD, synthetic SINEUPs are designed targeting mRNAs of interest. SINEUPs function in an array of cell lines and can be efficiently directed towards N-terminally tagged proteins. Their biological activity is retained in a miniaturized version within the range of small RNAs length. Its modular structure was exploited to successfully design synthetic SINEUPs targeting endogenous Parkinson’s disease-associated DJ-1 and proved to be active in different neuronal cell lines.In summary, SINEUPs represent the first scalable tool to increase synthesis of proteins of interest. We propose SINEUPs as reagents for molecular biology experiments, in protein manufacturing as well as in therapy of haploinsufficiencies.

Does stress remove the HDAC brakes for the formation and persistence of long-term memory?

Science.gov (United States)

White, André O.; Wood, Marcelo A.

2013-01-01

It has been known for numerous decades that gene expression is required for long-lasting forms of memory. In the past decade, the study of epigenetic mechanisms in memory processes has revealed yet another layer of complexity in the regulation of gene expression. Epigenetic mechanisms do not only provide complexity in the protein regulatory complexes that control coordinate transcription for specific cell function, but the epigenome encodes critical information that integrates experience and cellular history for specific cell functions as well. Thus, epigenetic mechanisms provide a unique mechanism of gene expression regulation for memory processes. This may be why critical negative regulators of gene expression, such as histone deacetylases (HDACs), have powerful effects on the formation and persistence of memory. For example, HDAC inhibition has been shown to transform a subthreshold learning event into robust long-term memory and also generate a form of long-term memory that persists beyond the point at which normal long-term memory fails. A key question that is explored in this review, from a learning and memory perspective, is whether stress-dependent signaling drives the formation and persistence of long-term memory via HDAC-dependent mechanisms. PMID:24149059

Changes in microbial populations of WPC34 and WPC80 whey protein during long term storage

Science.gov (United States)

The use of whey protein (WPC34 and WPC80) as a food ingredient and as a base for making biodegradable products is increasing. The need to alleviate world hunger in arid and semi-arid regions demands that we investigate the behavior of native bacteria in these products, especially during long term st...

[Long-term psychiatric hospitalizations].

Science.gov (United States)

Plancke, L; Amariei, A

2017-02-01

Long-term hospitalizations in psychiatry raise the question of desocialisation of the patients and the inherent costs. Individual indicators were extracted from a medical administrative database containing full-time psychiatric hospitalizations for the period 2011-2013 of people over 16 years old living in the French region of Nord-Pas-de-Calais. We calculated the proportion of people who had experienced a hospitalization with a duration of 292 days or more during the study period. A bivariate analysis was conducted, then ecological data (level of health-care offer, the deprivation index and the size of the municipalities of residence) were included into a multilevel regression model in order to identify the factors significantly related to variability of long-term hospitalization rates. Among hospitalized individuals in psychiatry, 2.6% had had at least one hospitalization of 292 days or more during the observation period; the number of days in long-term hospitalization represented 22.5% of the total of days of full-time hospitalization in psychiatry. The bivariate analysis revealed that seniority in the psychiatric system was strongly correlated with long hospitalization rates. In the multivariate analysis, the individual indicators the most related to an increased risk of long-term hospitalization were: total lack of autonomy (OR=9.0; 95% CI: 6.7-12.2; P<001); diagnoses of psychological development disorders (OR=9.7; CI95%: 4.5-20.6; P<.001); mental retardation (OR=4.5; CI95%: 2.5-8.2; P<.001): schizophrenia (OR=3.0; CI95%: 1.7-5.2; P<.001); compulsory hospitalization (OR=1.7; CI95%: 1.4-2.1; P<.001); having experienced therapeutic isolation (OR=1.8; CI95%: 1.5-2.1; P<.001). Variations of long-term hospitalization rates depending on the type of establishment were very high, but the density of hospital beds or intensity of ambulatory activity services were not significantly linked to long-term hospitalization. The inhabitants of small urban units had

Leucine-Enriched Essential Amino Acids Augment Mixed Protein Synthesis, But Not Collagen Protein Synthesis, in Rat Skeletal Muscle after Downhill Running

OpenAIRE

Kato, Hiroyuki; Suzuki, Hiromi; Inoue, Yoshiko; Suzuki, Katsuya; Kobayashi, Hisamine

2016-01-01

Mixed and collagen protein synthesis is elevated for as many as 3 days following exercise. Immediately after exercise, enhanced amino acid availability increases synthesis of mixed muscle protein, but not muscle collagen protein. However, the potential for synergic effects of amino acid ingestion with exercise on both mixed and collagen protein synthesis remains unclear. We investigated muscle collagen protein synthesis in rats following post-exercise ingestion of leucine-enriched essential a...

Deoxynivalenol affects in vitro intestinal epithelial cell barrier integrity through inhibition of protein synthesis

International Nuclear Information System (INIS)

Van De Walle, Jacqueline; Sergent, Therese; Piront, Neil; Toussaint, Olivier; Schneider, Yves-Jacques; Larondelle, Yvan

2010-01-01

Deoxynivalenol (DON), one of the most common mycotoxin contaminants of raw and processed cereal food, adversely affects the gastrointestinal tract. Since DON acts as a protein synthesis inhibitor, the constantly renewing intestinal epithelium could be particularly sensitive to DON. We analyzed the toxicological effects of DON on intestinal epithelial protein synthesis and barrier integrity. Differentiated Caco-2 cells, as a widely used model of the human intestinal barrier, were exposed to realistic intestinal concentrations of DON (50, 500 and 5000 ng/ml) during 24 h. DON caused a concentration-dependent decrease in total protein content associated with a reduction in the incorporation of [ 3 H]-leucine, demonstrating its inhibitory effect on protein synthesis. DON simultaneously increased the paracellular permeability of the monolayer as reflected through a decreased transepithelial electrical resistance associated with an increased paracellular flux of the tracer [ 3 H]-mannitol. A concentration-dependent reduction in the expression level of the tight junction constituent claudin-4 was demonstrated by Western blot, which was not due to diminished transcription, increased degradation, or NF-κB, ERK or JNK activation, and was also observed for a tight junction independent protein, i.e. intestinal alkaline phosphatase. These results demonstrate a dual toxicological effect of DON on differentiated Caco-2 cells consisting in an inhibition of protein synthesis as well as an increase in monolayer permeability, and moreover suggest a possible link between them through diminished synthesis of the tight junction constituent claudin-4.

mTORC1 Coordinates Protein Synthesis and Immunoproteasome Formation via PRAS40 to Prevent Accumulation of Protein Stress.

Science.gov (United States)

Yun, Young Sung; Kim, Kwan Hyun; Tschida, Barbara; Sachs, Zohar; Noble-Orcutt, Klara E; Moriarity, Branden S; Ai, Teng; Ding, Rui; Williams, Jessica; Chen, Liqiang; Largaespada, David; Kim, Do-Hyung

2016-02-18

Reduction of translational fidelity often occurs in cells with high rates of protein synthesis, generating defective ribosomal products. If not removed, such aberrant proteins can be a major source of cellular stress causing human diseases. Here, we demonstrate that mTORC1 promotes the formation of immunoproteasomes for efficient turnover of defective proteins and cell survival. mTORC1 sequesters precursors of immunoproteasome β subunits via PRAS40. When activated, mTORC1 phosphorylates PRAS40 to enhance protein synthesis and simultaneously to facilitate the assembly of the β subunits for forming immunoproteasomes. Consequently, the PRAS40 phosphorylations play crucial roles in clearing aberrant proteins that accumulate due to mTORC1 activation. Mutations of RAS, PTEN, and TSC1, which cause mTORC1 hyperactivation, enhance immunoproteasome formation in cells and tissues. Those mutations increase cellular dependence on immunoproteasomes for stress response and survival. These results define a mechanism by which mTORC1 couples elevated protein synthesis with immunoproteasome biogenesis to protect cells against protein stress. Copyright © 2016 Elsevier Inc. All rights reserved.

Cdk7 Is Required for Activity-Dependent Neuronal Gene Expression, Long-Lasting Synaptic Plasticity and Long-Term Memory

Directory of Open Access Journals (Sweden)

Guiqin He

2017-11-01

Full Text Available In the brain, de novo gene expression driven by learning-associated neuronal activities is critical for the formation of long-term memories. However, the signaling machinery mediating neuronal activity-induced gene expression, especially the rapid transcription of immediate-early genes (IEGs remains unclear. Cyclin-dependent kinases (Cdks are a family of serine/threonine kinases that have been firmly established as key regulators of transcription processes underling coordinated cell cycle entry and sequential progression in nearly all types of proliferative cells. Cdk7 is a subunit of transcriptional initiation factor II-H (TFIIH and the only known Cdk-activating kinase (CAK in metazoans. Recent studies using a novel Cdk7 specific covalent inhibitor, THZ1, revealed important roles of Cdk7 in transcription regulation in cancer cells. However, whether Cdk7 plays a role in the regulation of transcription in neurons remains unknown. In this study, we present evidence demonstrating that, in post-mitotic neurons, Cdk7 activity is positively correlated with neuronal activities in cultured primary neurons, acute hippocampal slices and in the brain. Cdk7 inhibition by THZ1 significantly suppressed mRNA levels of IEGs, selectively impaired long-lasting synaptic plasticity induced by 4 trains of high frequency stimulation (HFS and prevented the formation of long-term memories.

Protein synthesis in geostimulated root caps

Science.gov (United States)

Feldman, L. J.

1982-01-01

A study is presented of the processes occurring in the root cap of corn which are requisite for the formation of root cap inhibitor and which can be triggered or modulated by both light and gravity. The results of this study indicate the importance of protein synthesis for light-induced gravitropic bending in roots. Root caps in which protein synthesis is prevented are unable to induce downward bending. This suggests that light acts by stimulating proteins which are necessary for the translation of the gravitropic stimulus into a growth response (downward bending). The turnover of protein with time was also examined in order to determine whether light acts by stimulating the synthesis of unique proteins required for downward growth. It is found that auxin in combination with light allows for the translation of the gravitropic stimulus into a growth response at least in part through the modification of protein synthesis. It is concluded that unique proteins are stimulated by light and are involved in promoting the downward growth in roots which are responding to gravity.

Protein targeting to glycogen is a master regulator of glycogen synthesis in astrocytes

KAUST Repository

Ruchti, E.; Roach, P.J.; DePaoli-Roach, A.A.; Magistretti, Pierre J.; Allaman, I.

2016-01-01

to induce glycogen synthesis and accumulation. In contrast, siRNA-mediated downregulation of PTG resulted in a 2-fold decrease in glycogen levels. Interestingly, PTG downregulation strongly impaired long-term astrocytic glycogen synthesis induced by insulin

Relief memory consolidation requires protein synthesis within the nucleus accumbens.

Science.gov (United States)

Bruning, Johann E A; Breitfeld, Tino; Kahl, Evelyn; Bergado-Acosta, Jorge R; Fendt, Markus

2016-06-01

Relief learning refers to the association of a stimulus with the relief from an aversive event. The thus-learned relief stimulus then can induce, e.g., an attenuation of the startle response or approach behavior, indicating positive valence. Previous studies revealed that the nucleus accumbens is essential for the acquisition and retrieval of relief memory. Here, we ask whether the nucleus accumbens is also the brain site for consolidation of relief memory into a long-term form. In rats, we blocked local protein synthesis within the nucleus accumbens by local infusions of anisomycin at different time points during a relief conditioning experiment. Accumbal anisomycin injections immediately after the relief conditioning session, but not 4 h later, prevented the consolidation into long-term relief memory. The retention of already consolidated relief memory was not affected by anisomycin injections. This identifies a time window and site for relief memory consolidation. These findings should complement our understanding of the full range of effects of adverse experiences, including cases of their distortion in humans such as post-traumatic stress disorder and/or phobias. Copyright © 2016 Elsevier Ltd. All rights reserved.

The experience of facilitators and participants of long term condition self-management group programmes: A qualitative synthesis.

Science.gov (United States)

Hughes, Stephen; Lewis, Sophie; Willis, Karen; Rogers, Anne; Wyke, Sally; Smith, Lorraine

2017-12-01

Our aim was to systematically review the qualitative literature about the experiences of both facilitators and participants in a range of group-based programmes to support the self-management of long-term conditions. We searched 7 databases using the terms 'self-management', 'group' and 'qualitative'. Full text articles meeting the inclusion criteria were retrieved for review. A thematic synthesis approach was used to analyse the studies. 2126 articles were identified and 24 were included for review. Group participants valued being with similar others and perceived peer support benefits. Facilitators (HCP and lay) had limited group specific training, were uncertain of purpose and prioritised education and medical conformity over supportive group processes and the promotion of self-management agency and engagement. Overall, studies prioritised positive descriptions. Group programmes' medical self-management focus may reduce their ability to contribute to patient-valued outcomes. Further research is needed to explore this disconnect. This review supports broadening the scope of group-based programmes to foreground shared learning, social support and development of agency. It is of relevance to developers and facilitators of group self-management programmes and their ability to address the burden of long-term conditions. Copyright © 2017 Elsevier B.V. All rights reserved.

Long-Term Follow-up of a Successfully Treated Case of Congenital Pyridoxine-Dependent Epilepsy

OpenAIRE

Proudfoot, Malcolm; Jardine, Philip; Straukiene, Agne; Noad, Rupert; Parrish, Andrew; Ellard, Sian; Weatherby, Stuart

2013-01-01

Autosomal recessive disorders affecting pyridoxine (vitamin B6) metabolism are a rare but well-recognized cause of neonatal seizures. Antiquitin deficiency, caused by mutations in ALDH7A1, is a disorder of the lysine degradation pathway causing accumulation of an intermediate that complexes with pyridoxal phosphate. Reports of long-term follow-up of neonatal pyridoxine-dependent seizures (PDS) remain scarce and prognostic information is varied. We report a case of PDS in a 47-year-old lady wh...

Neurotrophins play differential roles in short and long-term recognition memory.

Science.gov (United States)

Callaghan, Charlotte K; Kelly, Aine M

2013-09-01

The neurotrophin family of proteins are believed to mediate various forms of synaptic plasticity in the adult brain. Here we have assessed the roles of these proteins in object recognition memory in the rat, using icv infusions of function-blocking antibodies or the tyrosine kinase antagonist, tyrphostin AG879, to block Trk receptors. We report that tyrphostin AG879 impairs both short-term and long-term recognition memory, indicating a requirement for Trk receptor activation in both processes. The effect of inhibition of each of the neurotrophins with activity-blocking neutralising antibodies was also tested. Treatment with anti-BDNF, anti-NGF or anti-NT4 had no effect on short-term memory, but blocked long-term recognition memory. Treatment with anti-NT3 had no effect on either process. We also assessed changes in expression of neurotrophins and their respective receptors in the hippocampus, dentate gyrus and perirhinal cortex over a 24 h period following training in the object recognition task. We observed time-dependent changes in expression of the Trk receptors and their ligands in the dentate gyrus and perirhinal cortex. The data are consistent with a pivotal role for neurotrophic factors in the expression of recognition memory. Copyright © 2013 Elsevier Inc. All rights reserved.

Content of intrinsic disorder influences the outcome of cell-free protein synthesis.

Science.gov (United States)

Tokmakov, Alexander A; Kurotani, Atsushi; Ikeda, Mariko; Terazawa, Yumiko; Shirouzu, Mikako; Stefanov, Vasily; Sakurai, Tetsuya; Yokoyama, Shigeyuki

2015-09-11

Cell-free protein synthesis is used to produce proteins with various structural traits. Recent bioinformatics analyses indicate that more than half of eukaryotic proteins possess long intrinsically disordered regions. However, no systematic study concerning the connection between intrinsic disorder and expression success of cell-free protein synthesis has been presented until now. To address this issue, we examined correlations of the experimentally observed cell-free protein expression yields with the contents of intrinsic disorder bioinformatically predicted in the expressed sequences. This analysis revealed strong relationships between intrinsic disorder and protein amenability to heterologous cell-free expression. On the one hand, elevated disorder content was associated with the increased ratio of soluble expression. On the other hand, overall propensity for detectable protein expression decreased with disorder content. We further demonstrated that these tendencies are rooted in some distinct features of intrinsically disordered regions, such as low hydrophobicity, elevated surface accessibility and high abundance of sequence motifs for proteolytic degradation, including sites of ubiquitination and PEST sequences. Our findings suggest that identification of intrinsically disordered regions in the expressed amino acid sequences can be of practical use for predicting expression success and optimizing cell-free protein synthesis.

Anodal tDCS over the Primary Motor Cortex Facilitates Long-Term Memory Formation Reflecting Use-Dependent Plasticity.

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Orjon Rroji

Full Text Available Previous research suggests that anodal transcranial direct current stimulation (tDCS over the primary motor cortex (M1 modulates NMDA receptor dependent processes that mediate synaptic plasticity. Here we test this proposal by applying anodal versus sham tDCS while subjects practiced to flex the thumb as fast as possible (ballistic movements. Repetitive practice of this task has been shown to result in performance improvements that reflect use-dependent plasticity resulting from NMDA receptor mediated, long-term potentiation (LTP-like processes. Using a double-blind within-subject cross-over design, subjects (n=14 participated either in an anodal or a sham tDCS session which were at least 3 months apart. Sham or anodal tDCS (1 mA was applied for 20 min during motor practice and retention was tested 30 min, 24 hours and one week later. All subjects improved performance during each of the two sessions (p < 0.001 and learning gains were similar. Our main result is that long term retention performance (i.e. 1 week after practice was significantly better when practice was performed with anodal tDCS than with sham tDCS (p < 0.001. This effect was large (Cohen's d=1.01 and all but one subject followed the group trend. Our data strongly suggest that anodal tDCS facilitates long-term memory formation reflecting use-dependent plasticity. Our results support the notion that anodal tDCS facilitates synaptic plasticity mediated by an LTP-like mechanism, which is in accordance with previous research.

Evidence for the involvement of a labile protein in stimulation of adrenal steroidogenesis under conditions not inhibitory to protein synthesis

International Nuclear Information System (INIS)

Krueger, R.J.; Orme-Johnson, N.R.

1988-01-01

Evidence is presented to support the hypothesis that synthesis of a labile protein is required for stimulation of steroidogenesis in rat adrenocortical cells. Amino acids L-canavanine and L-S-aminoethylcysteine, at concentrations as high as 5 mM, each inhibited steroidogenesis to a much greater extent than they inhibited protein synthesis. S-Aminoethylcysteine caused a 50% decrease in the stimulated rate of corticosterone production under conditions where incorporation of [35S]methionine into protein was unchanged. Both amino acids block stimulation of steroid synthesis at a step subsequent to the formation of cAMP and before the synthesis of progesterone. The onset of this effect, after the addition of the amino acids, on corticosterone production is quite rapid. These results provide support, that is not dependent on inhibition of protein synthesis, for the hypothesis that a labile protein mediates stimulation of steroidogenesis. Reversal of canavanine and S-aminoethylcysteine inhibition of steroidogenesis by arginine and lysine, respectively, suggests that the inhibitors are functioning as amino acid analogs. S-Aminoethylcysteine inhibits the incorporation of [3H]lysine into protein as well as inhibits steroidogenesis; further, [3H]S-aminoethylcysteine is incorporated into protein that is nonstimulatory. These results suggest that lysine residues play an essential role in the function of the labile protein or that the labile protein contains a large number of lysine residues

Chronological protein synthesis in regenerating rat liver.

Science.gov (United States)

He, Jinjun; Hao, Shuai; Zhang, Hao; Guo, Fuzheng; Huang, Lingyun; Xiao, Xueyuan; He, Dacheng

2015-07-01

Liver regeneration has been studied for decades; however, its regulation remains unclear. In this study, we report a dynamic tracing of protein synthesis in rat regenerating liver with a new proteomic technique, (35) S in vivo labeling analysis for dynamic proteomics (SiLAD). Conventional proteomic techniques typically measure protein alteration in accumulated amounts. The SiLAD technique specifically detects protein synthesis velocity instead of accumulated amounts of protein through (35) S pulse labeling of newly synthesized proteins, providing a direct way for analyzing protein synthesis variations. Consequently, protein synthesis within short as 30 min was visualized and protein regulations in the first 8 h of regenerating liver were dynamically traced. Further, the 3.5-5 h post partial hepatectomy (PHx) was shown to be an important regulatory turning point by acute regulation of many proteins in the initiation of liver regeneration. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Home or foster home care versus institutional long-term care for functionally dependent older people.

Science.gov (United States)

Young, Camilla; Hall, Amanda M; Gonçalves-Bradley, Daniela C; Quinn, Terry J; Hooft, Lotty; van Munster, Barbara C; Stott, David J

2017-04-03

Changing population demographics have led to an increasing number of functionally dependent older people who require care and medical treatment. In many countries, government policy aims to shift resources into the community from institutional care settings with the expectation that this will reduce costs and improve the quality of care compared. To assess the effects of long-term home or foster home care versus institutional care for functionally dependent older people. We searched the Cochrane Central Register of Controlled Trials (CENTRAL) via the Cochrane Library, MEDLINE, Embase, CINAHL, and two trials registers to November 2015. We included randomised and non-randomised trials, controlled before-after studies and interrupted time series studies complying with the EPOC study design criteria and comparing the effects of long-term home care versus institutional care for functionally dependent older people. Two reviewers independently extracted data and assessed the risk of bias of each included study. We reported the results narratively, as the substantial heterogeneity across studies meant that meta-analysis was not appropriate. We included 10 studies involving 16,377 participants, all of which were conducted in high income countries. Included studies compared community-based care with institutional care (care homes). The sample size ranged from 98 to 11,803 (median N = 204). There was substantial heterogeneity in the healthcare context, interventions studied, and outcomes assessed. One study was a randomised trial (N = 112); other included studies used designs that had potential for bias, particularly due lack of randomisation, baseline imbalances, and non-blinded outcome assessment. Most studies did not select (or exclude) participants for any specific disease state, with the exception of one study that only included patients if they had a stroke. All studies had methodological limitations, so readers should interpret results with caution.It is uncertain

Growth hormone therapy for children born small for gestational age: height gain is less dose dependent over the long term than over the short term.

Science.gov (United States)

de Zegher, Francis; Hokken-Koelega, Anita

2005-04-01

Approximately 3% of children are born small for gestational age (SGA), and approximately 10% of SGA children maintain a small body size throughout childhood and often into adult life. Among short SGA children, growth hormone (GH) therapy increases short-term growth in a dose-dependent manner; experience with long-term therapy is limited. To delineate the dose dependency of long-term height gain among short SGA children receiving GH therapy. We performed an epianalysis of the first adult height data for SGA children (n = 28) enrolled in 3 randomized trials comparing the growth-promoting efficacy of 2 continuous GH regimens (33 or 67 microg/kg per day for approximately 10 years, starting at approximately 5 years of age); in addition, we performed a meta-analysis of the adult height results published previously and those presented here. Epianalysis outcomes (n = 28) suggested that adult height increased more with a higher-dose regimen than with a lower-dose regimen. In the meta-analysis (n = 82), the higher-dose regimen was found to elicit a long-term height gain superior to that achieved with the lower-dose regimen by a mean of 0.4 SD (approximately 1 inch). Children who were shorter at the start of therapy experienced more long-term height gain. These findings confirm GH therapy as an effective and safe approach to reduce the adult height deficit that short SGA children otherwise face. In addition, the first meta-analysis indicated that height gain is less dose dependent over the long term than over the short term, at least within the dose range explored to date. For SGA children whose stature is not extremely short, current data support the use of a GH dose of approximately 33 microg/kg per day from start to adult height, particularly if treatment starts at a young age; shorter children (for example, height below -3 SD) might benefit from an approach in which short-term catch-up growth is achieved with a higher dose (> or =50 microg/kg per day) and long-term growth

Control of protein synthesis in the female pupa of Bombyx mori

International Nuclear Information System (INIS)

Yamao, Masami; Koga, Katsumi

1975-01-01

For the purpose of understanding the mechanisms of insect metamorphosis, protein synthesis by silkmoth pupae has been studied. Synthetic rate and contents of total RNA and protein changed markedly in the female pupae of Bombyx mori. Attempt was made to find what the limiting step for the synthesis of the bulk of proteins during the adult development of female pupae is. Several female pupae of hydridstrain were homogenized at each of stated periods in buffer. The ribosomal fraction prepared from the homogenates was incubated in the buffer containing 3 H-leucine or 3 H-phenylalanine. The incorporation of leucine depending on endogenous mRNA and that of phenylalanine directed by added poly U were the largest in 9--10 days and 7th day, respectively. From the results, the synthesis of protein during the late adult development of female silkworms is controlled at the level of mRNA. The increase of ribosomes, which were active to bind mRNA, preceded the appearance of available endogenous mRNA, and it may be attributed to neogenesis and ''run-off'' of previous ribosomes. It is conceivable that such neogenesis or run-off serves as less direct control for the protein synthesis during the metamorphosis of Bombix mori. (Kobatake, H.)

Medical and Psychiatric Effects of Long-Term Dependence on High Dose of tramadol.

Science.gov (United States)

El-Hadidy, Mohmed Adel; Helaly, Ahmed Mohamed Nabil

2015-04-01

Tramadol dependence has been studied recently after large-scale exposure. Although tramadol dependence has increased rapidly in Egypt since 2004, no studies have evaluated the effect of high dose long-term tramadol dependence. To address the chronic sequel of tramadol dependence over at least 5 years duration with a large dose (more than 675 mg/day, three tablets or more, each tablet of 225 mg). The study was aimed to check the physical and psychiatric status during tramadol dependence and 3 months after complete treatment. The present study was applied on 79 patients with single tramadol-dependence dose of 675 mg or more for 5 years or more. We examined the physical and psychological impact of tramadol abuse before and after 3 months of stoppage of the drug. The blood chemistry was nearly within normal parameters, although slight nonsignificant rise in liver enzymes was reported in some cases. Patients during tramadol dependence period were angry, hostile, and aggressive. On the other hand, after treatment the main problem observed was the significant increase in comorbid anxiety, depressive, and obsessive-compulsive symptoms, but no increase was found in psychotic symptoms. Tramadol-dependence dose was more important than duration of use in psychiatric illness. Tramadol dependence on high dose could be physically safe to some limit, but psychiatrically it has many side effects.

Protein synthesis and antioxidant capacity in aging mice : Effects of long-term voluntary exercise

NARCIS (Netherlands)

Vaanholt, Lobke M.; Speakman, John R.; Garland, Theodore; Lobley, Gerald E.; Visser, G. Henk

2008-01-01

Exercise increases metabolic rate and the production of reactive oxygen species (ROS) but also elevates protein turnover. ROS cause damage to macromolecules (e. g., proteins) and thereby contribute to aging. Protein turnover removes and replaces damaged proteins. The balance between these two

Albumin synthesis in protein energy malnutrition

Energy Technology Data Exchange (ETDEWEB)

Duggan, C; Hardy, S; Kleinman, R E [Harvard Medical School, Boston, MA (United States); Lembcke, J [Instituto de Investigacion Nutricional, La Molina, Lima (Peru); Young, V E [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States). Lab. of Human Nutrition

1994-12-31

The dietary treatment of protein-energy malnutrition (PEM) has been designed on an empirical basis, with outcomes for successful management including body weight gain and resolution of apathy. We propose using the measurements of protein synthesis as a more objective measure of renourishment. We will therefore randomize a group of malnourished children (weigh-for-height Z score <-2.0) to receive either a standard (10% of calories as protein) or increased (15%) amount of dietary protein early in their recovery phase. We will calculate albumin synthesis rates via the flooding dose technique, using {sup 13}C-leucine and serial measurements of {sup 13}C-enrichment of albumin. Isotope infusions will be performed on days one and three, following a standard three hour fast. Since albumin synthesis is reduced under the influence of cytokines which mediate the inflammatory response, results will be stratified according to the presence or absence of clinically apparent infections. We hypothesize that the provision of added dietary protein will optimize albumin synthesis rates in PEM as well as attenuate the reduction in albumin synthesis seen in the presence of infections. (author). 20 refs.

SPIN90 Modulates Long-Term Depression and Behavioral Flexibility in the Hippocampus

Directory of Open Access Journals (Sweden)

Dae Hwan Kim

2017-09-01

Full Text Available The importance of actin-binding proteins (ABPs in the regulation of synapse morphology and plasticity has been well established. SH3 protein interacting with Nck, 90 kDa (SPIN90, an Nck-interacting protein highly expressed in synapses, is essential for actin remodeling and dendritic spine morphology. Synaptic targeting of SPIN90 to spine heads or dendritic shafts depends on its phosphorylation state, leading to blockage of cofilin-mediated actin depolymerization and spine shrinkage. However, the physiological role of SPIN90 in long-term plasticity, learning and memory are largely unknown. In this study, we demonstrate that Spin90-knockout (KO mice exhibit substantial deficits in synaptic plasticity and behavioral flexibility. We found that loss of SPIN90 disrupted dendritic spine density in CA1 neurons of the hippocampus and significantly impaired long-term depression (LTD, leaving basal synaptic transmission and long-term potentiation (LTP intact. These impairments were due in part to deficits in AMPA receptor endocytosis and its pre-requisites, GluA1 dephosphorylation and postsynaptic density (PSD 95 phosphorylation, but also by an intrinsic activation of Akt-GSK3β signaling as a result of Spin90-KO. In accordance with these defects, mice lacking SPIN90 were found to carry significant deficits in object-recognition and behavioral flexibility, while learning ability was largely unaffected. Collectively, these findings demonstrate a novel modulatory role for SPIN90 in hippocampal LTD and behavioral flexibility.

Synaptic long-term potentiation and depression in the rat medial vestibular nuclei depend on neural activation of estrogenic and androgenic signals.

Directory of Open Access Journals (Sweden)

Mariangela Scarduzio

Full Text Available Estrogenic and androgenic steroids can be synthesised in the brain and rapidly modulate synaptic transmission and plasticity through direct interaction with membrane receptors for estrogens (ERs and androgens (ARs. We used whole cell patch clamp recordings in brainstem slices of male rats to explore the influence of ER and AR activation and local synthesis of 17β-estradiol (E2 and 5α-dihydrotestosterone (DHT on the long-term synaptic changes induced in the neurons of the medial vestibular nucleus (MVN. Long-term depression (LTD and long-term potentiation (LTP caused by different patterns of high frequency stimulation (HFS of the primary vestibular afferents were assayed under the blockade of ARs and ERs or in the presence of inhibitors for enzymes synthesizing DHT (5α-reductase and E2 (P450-aromatase from testosterone (T. We found that LTD is mediated by interaction of locally produced androgens with ARs and LTP by interaction of locally synthesized E2 with ERs. In fact, the AR block with flutamide prevented LTD while did not affect LTP, and the blockade of ERs with ICI 182,780 abolished LTP without influencing LTD. Moreover, the block of P450-aromatase with letrozole not only prevented the LTP induction, but inverted LTP into LTD. This LTD is likely due to the local activation of androgens, since it was abolished under blockade of ARs. Conversely, LTD was still induced in the presence of finasteride the inhibitor of 5α-reductase demonstrating that T is able to activate ARs and induce LTD even when DHT is not synthesized. This study demonstrates a key and opposite role of sex neurosteroids in the long-term synaptic changes of the MVN with a specific role of T-DHT for LTD and of E2 for LTP. Moreover, it suggests that different stimulation patterns can lead to LTD or LTP by specifically activating the enzymes involved in the synthesis of androgenic or estrogenic neurosteroids.

Synaptic long-term potentiation and depression in the rat medial vestibular nuclei depend on neural activation of estrogenic and androgenic signals.

Science.gov (United States)

Scarduzio, Mariangela; Panichi, Roberto; Pettorossi, Vito Enrico; Grassi, Silvarosa

2013-01-01

Estrogenic and androgenic steroids can be synthesised in the brain and rapidly modulate synaptic transmission and plasticity through direct interaction with membrane receptors for estrogens (ERs) and androgens (ARs). We used whole cell patch clamp recordings in brainstem slices of male rats to explore the influence of ER and AR activation and local synthesis of 17β-estradiol (E2) and 5α-dihydrotestosterone (DHT) on the long-term synaptic changes induced in the neurons of the medial vestibular nucleus (MVN). Long-term depression (LTD) and long-term potentiation (LTP) caused by different patterns of high frequency stimulation (HFS) of the primary vestibular afferents were assayed under the blockade of ARs and ERs or in the presence of inhibitors for enzymes synthesizing DHT (5α-reductase) and E2 (P450-aromatase) from testosterone (T). We found that LTD is mediated by interaction of locally produced androgens with ARs and LTP by interaction of locally synthesized E2 with ERs. In fact, the AR block with flutamide prevented LTD while did not affect LTP, and the blockade of ERs with ICI 182,780 abolished LTP without influencing LTD. Moreover, the block of P450-aromatase with letrozole not only prevented the LTP induction, but inverted LTP into LTD. This LTD is likely due to the local activation of androgens, since it was abolished under blockade of ARs. Conversely, LTD was still induced in the presence of finasteride the inhibitor of 5α-reductase demonstrating that T is able to activate ARs and induce LTD even when DHT is not synthesized. This study demonstrates a key and opposite role of sex neurosteroids in the long-term synaptic changes of the MVN with a specific role of T-DHT for LTD and of E2 for LTP. Moreover, it suggests that different stimulation patterns can lead to LTD or LTP by specifically activating the enzymes involved in the synthesis of androgenic or estrogenic neurosteroids.

Mitochondrial nucleoid interacting proteins support mitochondrial protein synthesis.

Science.gov (United States)

He, J; Cooper, H M; Reyes, A; Di Re, M; Sembongi, H; Litwin, T R; Gao, J; Neuman, K C; Fearnley, I M; Spinazzola, A; Walker, J E; Holt, I J

2012-07-01

Mitochondrial ribosomes and translation factors co-purify with mitochondrial nucleoids of human cells, based on affinity protein purification of tagged mitochondrial DNA binding proteins. Among the most frequently identified proteins were ATAD3 and prohibitin, which have been identified previously as nucleoid components, using a variety of methods. Both proteins are demonstrated to be required for mitochondrial protein synthesis in human cultured cells, and the major binding partner of ATAD3 is the mitochondrial ribosome. Altered ATAD3 expression also perturbs mtDNA maintenance and replication. These findings suggest an intimate association between nucleoids and the machinery of protein synthesis in mitochondria. ATAD3 and prohibitin are tightly associated with the mitochondrial membranes and so we propose that they support nucleic acid complexes at the inner membrane of the mitochondrion.

Analysing the origin of long-range interactions in proteins using lattice models

Directory of Open Access Journals (Sweden)

Unger Ron

2009-01-01

Full Text Available Abstract Background Long-range communication is very common in proteins but the physical basis of this phenomenon remains unclear. In order to gain insight into this problem, we decided to explore whether long-range interactions exist in lattice models of proteins. Lattice models of proteins have proven to capture some of the basic properties of real proteins and, thus, can be used for elucidating general principles of protein stability and folding. Results Using a computational version of double-mutant cycle analysis, we show that long-range interactions emerge in lattice models even though they are not an input feature of them. The coupling energy of both short- and long-range pairwise interactions is found to become more positive (destabilizing in a linear fashion with increasing 'contact-frequency', an entropic term that corresponds to the fraction of states in the conformational ensemble of the sequence in which the pair of residues is in contact. A mathematical derivation of the linear dependence of the coupling energy on 'contact-frequency' is provided. Conclusion Our work shows how 'contact-frequency' should be taken into account in attempts to stabilize proteins by introducing (or stabilizing contacts in the native state and/or through 'negative design' of non-native contacts.

Synthesis of Lipidated Proteins.

Science.gov (United States)

Mejuch, Tom; Waldmann, Herbert

2016-08-17

Protein lipidation is one of the major post-translational modifications (PTM) of proteins. The attachment of the lipid moiety frequently determines the localization and the function of the lipoproteins. Lipidated proteins participate in many essential biological processes in eukaryotic cells, including vesicular trafficking, signal transduction, and regulation of the immune response. Malfunction of these cellular processes usually leads to various diseases such as cancer. Understanding the mechanism of cellular signaling and identifying the protein-protein and protein-lipid interactions in which the lipoproteins are involved is a crucial task. To achieve these goals, fully functional lipidated proteins are required. However, access to lipoproteins by means of standard expression is often rather limited. Therefore, semisynthetic methods, involving the synthesis of lipidated peptides and their subsequent chemoselective ligation to yield full-length lipoproteins, were developed. In this Review we summarize the commonly used methods for lipoprotein synthesis and the development of the corresponding chemoselective ligation techniques. Several key studies involving full-length semisynthetic lipidated Ras, Rheb, and LC3 proteins are presented.

The role of GABA in NMDA-dependent long term depression (LTD) of rat medial vestibular nuclei.

Science.gov (United States)

Grassi, S; Della Torre, G; Capocchi, G; Zampolini, M; Pettorossi, V E

1995-11-20

The role of GABA in NMDA-dependent long term depression (LTD) in the medial vestibular nuclei (MVN) was studied on rat brainstem slices. High frequency stimulation (HFS) of the primary vestibular afferents induces a long lasting reduction of the polysynaptic (N2) component of the field potentials recorded in the dorsal portion of the MVN. The induction but not the maintenance of this depression was abolished by AP5, a specific blocking agent for glutamate NMDA receptors. The involvement of GABA in mediating the depression was checked by applying the GABAA and GABAB receptor antagonists, bicuculline and saclofen, before and after HFS. Under bicuculline and saclofen perfusion, HFS provoked a slight potentiation of the N2 wave, while the N2 depression clearly emerged after drug wash-out. This indicates that GABA is not involved in inducing the long term effect, but it is necessary for its expression. Similarly, the LTD reversed and a slight potentiation appeared when both drugs were administered after its induction. Most of these effects were due to the bicuculline, suggesting that GABAA receptors contribute to LTD more than GABAB do. According to our results, it is unlikely that the long lasting vestibular depression is the result of a homosynaptic LTD. On the contrary, our findings suggest that the depression is due to an enhancement of the GABA inhibitory effect, caused by an HFS dependent increase in gabaergic interneuron activity, which resets vestibular neuron excitability at a lower level.

Respiratory alkalosis and associated electrolytes in long-term ventilator dependent persons with tetraplegia.

Science.gov (United States)

Watt, J W; Silva, P

2001-11-01

A pilot case control study of the acid-base and electrolyte status in 30 long-term ventilator-dependent (LTVD) and 30 self ventilating persons with tetraplegia. To assess the extent of respiratory alkalosis and screen for associated hypokalaemia, hypomagnesaemia and/or hypophosphataemia. Medically stable persons with tetraplegia under the long-term care of the Southport Spinal Injuries Centre, England. Blood gases and electrolytes were sampled from 30 control patients with tetraplegia and from 30 patients having been LTVD for more than 12 months. All the blood gas measurements in the LTVD group lay outside both the reference range and the 95% confidence intervals (CI) of the control group: pH 7.46 (0.06); PCO(2) 3.46 (1.1) kPa; bicarbonate 18.3 (3.8) and base excess -3.2 (2.8) mmol/l; PO(2) 13.8 (2.8) kPa (means and standard deviations). The serum potassium, magnesium, phosphate, and sodium means lay within the reference ranges but the potassium, phosphate and calcium were at or below the 95% CI of the control values. One patient on part-time ventilatory support having less bicarbonate compensation had low serum electrolytes during ventilation. There was no evidence of biochemical jeopardy from long-term mechanical hyperventilation although acutely administered hyperventilation has the potential to cause falls in serum potassium, magnesium and phosphate and so caution should be exercised in part-time ventilated persons. The full range of electrolytes should be assayed during stabilisation in LTVD and periodically thereafter. Hyperventilation helps to maintain good oxygenation in LTVD persons with paralysis and normal lungs. None.

Long-term follow-up after liver transplantation for erythropoietic protoporphyria

NARCIS (Netherlands)

Meerman, L; Haagsma, EB; Gouw, ASH; Slooff, MJH; Jansen, PLM

Objective Erythropoietic protoporphyria (EPP) is an inherited disorder of haem synthesis, causing excess of protoporphyrin in blood, skin, liver and other organs, Protoporphyrin causes rapidly progressive liver failure in a minority of EPP patients. Long-term follow-up after liver transplantation

Dependency on de novo protein synthesis and proteomic changes during metamorphosis of the marine bryozoan Bugula neritina

KAUST Repository

Wong, Yue Him; Arellano, Shawn M; Zhang, Huoming; Ravasi, Timothy; Qian, Pei-Yuan

2010-01-01

synthesis of proteins and, instead, involves post-translational modifications of existing proteins, providing a simple mechanism to quickly initiate metamorphosis. To test our hypothesis, we challenged B. neritina larvae with transcription and translation

Exogenous glutamate induces short and long-term potentiation in the rat medial vestibular nuclei.

Science.gov (United States)

Grassi, S; Frondaroli, A; Pessia, M; Pettorossi, V E

2001-08-08

In rat brain stem slices, high concentrations of exogenous glutamate induce long-term potentiation (LTP) of the field potentials evoked in the medial vestibular nuclei (MVN) by vestibular afferent stimulation. At low concentrations, glutamate can also induce short-term potentiation (STP), indicating that LTP and STP are separate events depending on the level of glutamatergic synapse activation. LTP and STP are prevented by blocking NMDA receptors and nitric oxide (NO) synthesis. Conversely, blocking platelet-activating factor (PAF) and group I metabotropic glutamate receptors only prevents the full development of LTP. Moreover, in the presence of blocking agents, glutamate causes transient inhibition, suggesting that when potentiation is impeded, exogenous glutamate can activate presynaptic mechanisms that reduce glutamate release.

Effect of long-term refeeding on protein metabolism in patients with cirrhosis of the liver

DEFF Research Database (Denmark)

Kondrup, J; Nielsen, K; Juul, A

1997-01-01

in protein synthesis was associated with significant increases in plasma concentrations of total amino acids (25%), leucine (58%), isoleucine (82%), valine (72%), proline (48%) and triiodothyronine (27%) while insulin, growth hormone, insulin-like growth factor (IGF)-I and IGF-binding protein-3 were...... a normal protein requirement with the patients who had an increased protein requirement suggests that the increased protein requirement is due to a primary increase in protein degradation. It is speculated that this is due to low levels of IGF-I secondary to impaired liver function, since initial plasma...

Using the fluorescence red edge effect to assess the long-term stability of lyophilized protein formulations.

Science.gov (United States)

Qian, Ken K; Grobelny, Pawel J; Tyagi, Madhusudan; Cicerone, Marcus T

2015-04-06

Nanosecond relaxation processes in sugar matrices are causally linked through diffusional processes to protein stability in lyophilized formulations. Long-term protein degradation rates track mean-squared displacement (⟨u(2)⟩) of hydrogen atoms in sugar glasses, a parameter describing dynamics on a time scale of picoseconds to nanoseconds. However, measurements of ⟨u(2)⟩ are usually performed by neutron scattering, which is not conducive to rapid formulation screening in early development. Here, we present a benchtop technique to derive a ⟨u(2)⟩ surrogate based on the fluorescence red edge effect. Glycerol, lyophilized trehalose, and lyophilized sucrose were used as model systems. Samples containing 10(-6) mole fraction of rhodamine 6G, a fluorophore, were excited at either 532 nm (main peak) or 566 nm (red edge), and the ⟨u(2)⟩ surrogate was determined based the corresponding Stokes shifts. Results showed reasonable agreement between ⟨u(2)⟩ from neutron scattering and the surrogate from fluorescence, although deviations were observed at very low temperatures. We discuss the sources of the deviations and suggest technique improvements to ameliorate these. We expect that this method will be a valuable tool to evaluate lyophilized sugar matrices with respect to their ability to protect proteins from diffusion-limited degradation processes during long-term storage. Additionally, the method may have broader applications in amorphous pharmaceutical solids.

Does stress remove the HDAC brakes for the formation and persistence of long-term memory?

Science.gov (United States)

White, André O; Wood, Marcelo A

2014-07-01

It has been known for numerous decades that gene expression is required for long-lasting forms of memory. In the past decade, the study of epigenetic mechanisms in memory processes has revealed yet another layer of complexity in the regulation of gene expression. Epigenetic mechanisms do not only provide complexity in the protein regulatory complexes that control coordinate transcription for specific cell function, but the epigenome encodes critical information that integrates experience and cellular history for specific cell functions as well. Thus, epigenetic mechanisms provide a unique mechanism of gene expression regulation for memory processes. This may be why critical negative regulators of gene expression, such as histone deacetylases (HDACs), have powerful effects on the formation and persistence of memory. For example, HDAC inhibition has been shown to transform a subthreshold learning event into robust long-term memory and also generate a form of long-term memory that persists beyond the point at which normal long-term memory fails. A key question that is explored in this review, from a learning and memory perspective, is whether stress-dependent signaling drives the formation and persistence of long-term memory via HDAC-dependent mechanisms. Copyright © 2013 Elsevier Inc. All rights reserved.

Generalization of fear inhibition by disrupting hippocampal protein synthesis-dependent reconsolidation process.

Science.gov (United States)

Yang, Chih-Hao; Huang, Chiung-Chun; Hsu, Kuei-Sen

2011-09-01

Repetitive replay of fear memories may precipitate the occurrence of post-traumatic stress disorder and other anxiety disorders. Hence, the suppression of fear memory retrieval may help prevent and treat these disorders. The formation of fear memories is often linked to multiple environmental cues and these interconnected cues may act as reminders for the recall of traumatic experiences. However, as a convenience, a simple paradigm of one cue pairing with the aversive stimulus is usually used in studies of fear conditioning in animals. Here, we built a more complex fear conditioning model by presenting several environmental stimuli during fear conditioning and characterize the effectiveness of extinction training and the disruption of reconsolidation process on the expression of learned fear responses. We demonstrate that extinction training with a single-paired cue resulted in cue-specific attenuation of fear responses but responses to other cures were unchanged. The cue-specific nature of the extinction persisted despite training sessions combined with D-cycloserine treatment reveals a significant weakness in extinction-based treatment. In contrast, the inhibition of the dorsal hippocampus (DH) but not the basolateral amygdala (BLA)-dependent memory reconsolidation process using either protein synthesis inhibitors or genetic disruption of cAMP-response-element-binding protein-mediated transcription comprehensively disrupted the learned connections between fear responses and all paired environmental cues. These findings emphasize the distinct role of the DH and the BLA in the reconsolidation process of fear memories and further indicate that the disruption of memory reconsolidation process in the DH may result in generalization of fear inhibition.

Synthesis on the spent fuel long term evolution

Energy Technology Data Exchange (ETDEWEB)

Ferry, C.; Poinssot, Ch.; Lovera, P.; Poulesquen, A. [CEA Saclay, Dept. de Physico-Chimie (DEN/DPC), 91 - Gif sur Yvette (France); Broudic, V. [CEA Cadarache, Direction des Reacteurs Nucleaires (DRN), 13 - Saint Paul lez Durance (France); Cappelaere, Ch. [CEA Saclay, Dept. des Materiaux pour le Nucleaire(DMN), 91 - Gif-sur-Yvette (France); Desgranges, L. [CEA Cadarache, Direction des Reacteurs Nucleaires (DRN), 13 - Saint-Paul-lez-Durance (France); Garcia, Ph. [CEA Cadarache, Dept. d' Etudes des Combustibles (DEC), 13 - Saint Paul lez Durance (France); Jegou, Ch.; Roudil, D. [CEA Valrho, Dir. de l' Energie Nucleaire (DEN), 30 - Marcoule (France); Lovera, P.; Poulesquen, A. [CEA Saclay, Dept. de Physico-Chimie (DPC), 91 - Gif sur Yvette (France); Marimbeau, P. [CEA Cadarache, Dir. de l' Energie Nucleaire (DEN), 13 - Saint-Paul-lez-Durance (France); Gras, J.M.; Bouffioux, P. [Electricite de France (EDF), 75 - Paris (France)

2005-07-01

The French research on spent fuel long term evolution has been performed by CEA (Commissariat a l'Energie Atomique) since 1999 in the PRECCI project with the support of EDF (Electricite de France). These studies focused on the spent fuel behaviour under various conditions encountered in dry storage or in deep geological disposal. Three main types of conditions were discerned: - The evolution in a closed system which corresponds to the normal scenario in storage and to the first confinement phase in disposal; - The evolution in air which corresponds to an incidental loss of confinement during storage or to a rupture of the canister before the site re-saturation in geological disposal; - The evolution in water which corresponds to the normal scenario after the breaching of the canister in repository conditions. This document produced in the frame of the PRECCI project is an overview of the state of knowledge in 2004 concerning the long-term behavior of spent fuel under these various conditions. The state of the art was derived from the results obtained under the PRECCI project as well as from a review of the literature and of data acquired under the European project on Spent Fuel Stability under Repository Conditions. The main results issued from the French research are underlined. (authors)

Synthesis on the spent fuel long term evolution

International Nuclear Information System (INIS)

Ferry, C.; Poinssot, Ch.; Lovera, P.; Poulesquen, A.; Broudic, V.; Cappelaere, Ch.; Desgranges, L.; Garcia, Ph.; Jegou, Ch.; Roudil, D.; Lovera, P.; Poulesquen, A.; Marimbeau, P.; Gras, J.M.; Bouffioux, P.

2005-01-01

The French research on spent fuel long term evolution has been performed by CEA (Commissariat a l'Energie Atomique) since 1999 in the PRECCI project with the support of EDF (Electricite de France). These studies focused on the spent fuel behaviour under various conditions encountered in dry storage or in deep geological disposal. Three main types of conditions were discerned: - The evolution in a closed system which corresponds to the normal scenario in storage and to the first confinement phase in disposal; - The evolution in air which corresponds to an incidental loss of confinement during storage or to a rupture of the canister before the site re-saturation in geological disposal; - The evolution in water which corresponds to the normal scenario after the breaching of the canister in repository conditions. This document produced in the frame of the PRECCI project is an overview of the state of knowledge in 2004 concerning the long-term behavior of spent fuel under these various conditions. The state of the art was derived from the results obtained under the PRECCI project as well as from a review of the literature and of data acquired under the European project on Spent Fuel Stability under Repository Conditions. The main results issued from the French research are underlined. (authors)

Measurement of local cerebral protein synthesis in vivo: influence of recycling of amino acids derived from protein degradation

International Nuclear Information System (INIS)

Smith, C.B.; Deibler, G.E.; Eng, N.; Schmidt, K.; Sokoloff, L.

1988-01-01

A quantitative autoradiographic method for the determination of local rates of protein synthesis in brain in vivo is being developed. The method employs L-[1- 14 C]leucine as the radiolabeled tracer. A comprehensive model has been designed that takes into account intracellular and extracellular spaces, intracellular compartmentation of leucine, and the possibility of recycling of unlabeled leucine derived from steady-state degradation of protein into the precursor pool for protein synthesis. We have evaluated the degree of recycling by measuring the ratio of the steady-state precursor pool distribution space for labeled leucine to that of unlabeled leucine. The values obtained were 0.58 in whole brain and 0.47 in liver. These results indicate that there is significant recycling of unlabeled amino acids derived from steady-state protein degradation in both tissues. Any method for the determination of rates of cerebral protein synthesis in vivo with labeled tracers that depends on estimation of precursor pool specific activity in tissue from measurements in plasma must take this recycling into account

Does therapeutic writing help people with long-term conditions? Systematic review, realist synthesis and economic considerations.

Science.gov (United States)

Nyssen, Olga P; Taylor, Stephanie J C; Wong, Geoff; Steed, Elizabeth; Bourke, Liam; Lord, Joanne; Ross, Carol A; Hayman, Sheila; Field, Victoria; Higgins, Ailish; Greenhalgh, Trisha; Meads, Catherine

2016-04-01

Writing therapy to improve physical or mental health can take many forms. The most researched model of therapeutic writing (TW) is unfacilitated, individual expressive writing (written emotional disclosure). Facilitated writing activities are less widely researched. Databases, including MEDLINE, EMBASE, PsycINFO, Linguistics and Language Behaviour Abstracts, Allied and Complementary Medicine Database and Cumulative Index to Nursing and Allied Health Literature, were searched from inception to March 2013 (updated January 2015). Four TW practitioners provided expert advice. Study procedures were conducted by one reviewer and checked by a second. Randomised controlled trials (RCTs) and non-randomised comparative studies were included. Quality was appraised using the Cochrane risk-of-bias tool. Unfacilitated and facilitated TW studies were analysed separately under International Classification of Diseases, Tenth Revision chapter headings. Meta-analyses were performed where possible using RevMan version 5.2.6 (RevMan 2012, The Cochrane Collaboration, The Nordic Cochrane Centre, Copenhagen, Denmark). Costs were estimated from a UK NHS perspective and three cost-consequence case studies were prepared. Realist synthesis followed Realist and Meta-narrative Evidence Synthesis: Evolving Standards guidelines. To review the clinical effectiveness and cost-effectiveness of TW for people with long-term conditions (LTCs) compared with no writing, or other controls, reporting any relevant clinical outcomes. To conduct a realist synthesis to understand how TW might work, and for whom. From 14,658 unique citations, 284 full-text papers were reviewed and 64 studies (59 RCTs) were included in the final effectiveness reviews. Five studies examined facilitated TW; these were extremely heterogeneous with unclear or high risk of bias but suggested that facilitated TW interventions may be beneficial in individual LTCs. Unfacilitated expressive writing was examined in 59 studies of variable

Long-term potentiation in the rat medial vestibular nuclei depends on locally synthesized 17beta-estradiol.

Science.gov (United States)

Grassi, Silvarosa; Frondaroli, Adele; Dieni, Cristina; Scarduzio, Mariangela; Pettorossi, Vito E

2009-08-26

In male rat brainstem slices, we investigated the involvement of locally synthesized 17beta-estradiol (E(2)) in the induction in the medial vestibular nucleus (MVN) of long-term potentiation (LTP) by high-frequency stimulation (HFS) of the primary vestibular afferents. We demonstrated that the blockade of aromatase by letrozole or of E(2) receptors (ERalpha and ERbeta) by ICI 182,780 prevented the HFS-induced LTP of the N1 wave of the evoked field potential (FP) without affecting baseline responses. Only prolonged afferent activation could induce low LTP. In contrast, HFS applied under a combined blockade of GABA(A) receptors and aromatase or ERs was still able to induce LTP, but it was significantly lower and slower. These findings demonstrate that E(2) does not have a tonic influence on the activity of the MVN neurons and provide the first evidence of the crucial role played by local synthesis of E(2) in inducing LTP. We suggest that the synthesis of E(2) occurs after aromatase activation during HFS and facilitates the development of vestibular synaptic plasticity by influencing glutamate and GABA transmission.

Long-term follow-up after liver transplantation for erythropoietic protoporphyria

NARCIS (Netherlands)

Meerman, L.; Haagsma, E. B.; Gouw, A. S.; Slooff, M. J.; Jansen, P. L.

1999-01-01

Erythropoietic protoporphyria (EPP) is an inherited disorder of haem synthesis, causing excess of protoporphyrin in blood, skin, liver and other organs. Protoporphyrin causes rapidly progressive liver failure in a minority of EPP patients. Long-term follow-up after liver transplantation for EPP is

Long-term nitrogen regulation of forest carbon sequestration

Science.gov (United States)

Yang, Y.; Luo, Y.

2009-12-01

It is well established that nitrogen (N) limits plant production but unclear how N regulates long-term terrestrial carbon (C) sequestration in response to rising atmospheric C dioxide (CO2)(Luo et al., 2004). Most experimental evidence on C-N interactions is primarily derived from short-term CO2 manipulative studies (e.g. Oren et al., 2001; Reich et al., 2006a), which abruptly increase C inputs into ecosystems and N demand from soil while atmospheric CO2 concentration in the real world is gradually increasing over time (Luo & Reynolds, 1999). It is essential to examine long-term N regulations of C sequestration in natural ecosystems. Here we present results of a synthesis of more than 100 studies on long-term C-N interactions during secondary succession. C significantly accumulates in plant, litter and forest floor in most studies, and in mineral soil in one-third studies during stand development. Substantial increases in C stock are tightly coupled with N accretion. The C: N ratio in plant increases with stand age in most cases, but remains relatively constant in litter, forest floor and mineral soil. Our results suggest that natural ecosystems could have the intrinsic capacity to maintain long-term C sequestration through external N accrual, high N use efficiency, and efficient internal N cycling.

Sex-Dependent and Independent Effects of Long-Term Voluntary Wheel Running on Bdnf mRNA and Protein Expression

OpenAIRE

Venezia, Andrew C.; Guth, Lisa M.; Sapp, Ryan M.; Spangenburg, Espen E.; Roth, Stephen M.

2016-01-01

The beneficial effects of physical activity on brain health (synaptogenesis, neurogenesis, enhanced synaptic plasticity, improved learning and memory) appear to be mediated through changes in region-specific expression of neurotrophins, transcription factors, and postsynaptic receptors, though investigations of sex differences in response to long-term voluntary wheel running are limited.

Long-term exercise in mice has sex-dependent benefits on body composition and metabolism during aging.

Science.gov (United States)

McMullan, Rachel C; Kelly, Scott A; Hua, Kunjie; Buckley, Brian K; Faber, James E; Pardo-Manuel de Villena, Fernando; Pomp, Daniel

2016-11-01

Aging is associated with declining exercise and unhealthy changes in body composition. Exercise ameliorates certain adverse age-related physiological changes and protects against many chronic diseases. Despite these benefits, willingness to exercise and physiological responses to exercise vary widely, and long-term exercise and its benefits are difficult and costly to measure in humans. Furthermore, physiological effects of aging in humans are confounded with changes in lifestyle and environment. We used C57BL/6J mice to examine long-term patterns of exercise during aging and its physiological effects in a well-controlled environment. One-year-old male (n = 30) and female (n = 30) mice were divided into equal size cohorts and aged for an additional year. One cohort was given access to voluntary running wheels while another was denied exercise other than home cage movement. Body mass, composition, and metabolic traits were measured before, throughout, and after 1 year of treatment. Long-term exercise significantly prevented gains in body mass and body fat, while preventing loss of lean mass. We observed sex-dependent differences in body mass and composition trajectories during aging. Wheel running (distance, speed, duration) was greater in females than males and declined with age. We conclude that long-term exercise may serve as a preventive measure against age-related weight gain and body composition changes, and that mouse inbred strains can be used to characterize effects of long-term exercise and factors (e.g. sex, age) modulating these effects. These findings will facilitate studies on relationships between exercise and health in aging populations, including genetic predisposition and genotype-by-environment interactions. © 2016 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of The Physiological Society and the American Physiological Society.

Effect of a long-term high-protein diet on survival, obesity development, and gut microbiota in mice

NARCIS (Netherlands)

Kiilerich, Pia; Myrmel, Lene Secher; Fjære, Even; Hao, Qin; Hugenholtz, Floor; Sonne, Si Brask; Derrien, Muriel; Pedersen, Lone Møller; Petersen, Rasmus Koefoed; Mortensen, Alicja; Licht, Tine Rask; Rømer, Maria Unni; Vogel, Ulla Birgitte; Waagbø, Linn Jeanette; Giallourou, Natasa; Feng, Qiang; Xiao, Liang; Liu, Chuan; Liaset, Bjørn; Kleerebezem, Michiel; Wang, Jun; Madsen, Lise; Kristiansen, Karsten

2016-01-01

Female C57BL/6J mice were fed a regular low-fat diet or high-fat diets combined with either high or low protein-to-sucrose ratios during their entire lifespan to examine the long-term effects on obesity development, gut microbiota, and survival. Intake of a high-fat diet with a low

Regulation of insulin-like growth factor-binding protein-1 synthesis and secretion by progestin and relaxin in long term cultures of human endometrial stromal cells

Energy Technology Data Exchange (ETDEWEB)

Bell, S.C.; Jackson, J.A.; Ashmore, J.; Zhu, H.H.; Tseng, L. (Univ. of Leicester, (United Kingdom))

1991-05-01

The decidualized endometrium during the first trimester of pregnancy synthesizes and secretes a 32-kDa insulin-like growth factor-binding protein (termed hIGFBP-1) at high levels. IGFBP-1 is the major soluble protein product of this tissue and is principally localized to the differentiated endometrial stromal cell, the decidual cell. In the present study long term culture of stromal cells from the nonpregnant endometrium have been employed to elucidate the hormonal requirements for IGFBP-1 production. Immunoreactive IGFBP-1 was undetectable in control cultures. However, inclusion of medroxyprogesterone acetate (MPA) induced rates of 0.35 +/- 0.09 microgram/0.1 mg cell DNA.day after 20-30 days. In these cultures cells exhibited morphological changes consistent with decidual cell differentiation. In all cultures removal of MPA after exposure for 10-16 days, with or without subsequent inclusion of relaxin (RLX), increased production of IGFBP-1 450- to 4600-fold to rates of 150-710 micrograms/0.1 mg cell DNA.day or 26-131 micrograms/10(6) cells.day on days 24-26. The rates tended to be higher with the inclusion of RLX and were sustained in contrast to cultures without RLX, where rates fell by day 30. Individual cultures responded differently to RLX when added from the initiation of culture, with either a response similar to MPA alone or a cyclical change in production, achieving maximal rates of 190-290 micrograms/0.1 mg cell DNA.day. Cultures in which RLX alone induced high IGFBP-1 high production were obtained from endometrium during the progesterone-dominated luteal phase. In cultures exhibiting high rates of immunoreactive IGFBP-1 production, the protein represented their major secretory protein product. This was confirmed by ({sup 35}S)methionine incorporation and the presence of IGFBP-1 as the predominant protein in serum-free culture medium.

The antimetabolite ara-CTP blocks long-term memory of conditioned taste aversion.

Science.gov (United States)

Wang, Jianpeng; Ren, Keqin; Pérez, Javier; Silva, Alcino J; Peña de Ortiz, Sandra

2003-01-01

We examined the hypothesis that processes related to DNA recombination and repair are involved in learning and memory. Rats received intracerebroventricular (i.c.v.) infusions of the antimetabolite 1-beta-D-arabinofuranosylcytosine triphosphate (ara-CTP) or its precursor cytosine arabinoside (ara-C) 30 min prior to conditioned taste aversion (CTA) training. Both ara-CTP and ara-C caused significant impairments in long-term memory (LTM) of CTA. Control experiments indicate that the effect of ara-CTP on CTA memory is related to interference with learning. Furthermore, as it was previously demonstrated for the protein synthesis inhibitor anisomycin, ara-CTP had no effect on CTA memory when it was injected 1 h after training. Importantly, although both ara-CTP and anisomycin significantly blocked LTM in the task, short-term memory (STM) measured 1 h after training was not affected by either of the drugs. Finally, ara-CTP had no effect on in vitro transcription, but it did effectively block nonhomologous DNA end joining (NHEJ) activity of brain protein extracts. We suggest that DNA ligase-mediated DNA recombination and repair processes are necessary for the expression of LTM in the brain.

Whereas Short-Term Facilitation Is Presynaptic, Intermediate-Term Facilitation Involves Both Presynaptic and Postsynaptic Protein Kinases and Protein Synthesis

Science.gov (United States)

Jin, Iksung; Kandel, Eric R.; Hawkins, Robert D.

2011-01-01

Whereas short-term plasticity involves covalent modifications that are generally restricted to either presynaptic or postsynaptic structures, long-term plasticity involves the growth of new synapses, which by its nature involves both pre- and postsynaptic alterations. In addition, an intermediate-term stage of plasticity has been identified that…

Glutamic Acid as Enhancer of Protein Synthesis Kinetics in Hepatocytes from Old Rats.

Science.gov (United States)

Brodsky, V Y; Malchenko, L A; Butorina, N N; Lazarev Konchenko, D S; Zvezdina, N D; Dubovaya, T K

2017-08-01

Dense cultures of hepatocytes from old rats (~2 years old, body weight 530-610 g) are different from similar cultures of hepatocytes from young rats by the low amplitude of protein synthesis rhythm. Addition of glutamic acid (0.2, 0.4, or 0.6 mg/ml) into the culture medium with hepatocytes of old rats resulted in increase in the oscillation amplitudes of the protein synthesis rhythm to the level of young rats. A similar action of glutamic acid on the protein synthesis kinetics was observed in vivo after feeding old rats with glutamic acid. Inhibition of metabotropic receptors of glutamic acid with α-methyl-4-carboxyphenylglycine (0.01 mg/ml) abolished the effect of glutamic acid. The amplitude of oscillation of the protein synthesis rhythm in a cell population characterizes synchronization of individual oscillations caused by direct cell-cell communications. Hence, glutamic acid, acting as a receptor-dependent transmitter, enhanced direct cell-cell communications of hepatocytes that were decreased with aging. As differentiated from other known membrane signaling factors (gangliosides, norepinephrine, serotonin, dopamine), glutamic acid can penetrate into the brain and thus influence the communications and protein synthesis kinetics that are disturbed with aging not only in hepatocytes, but also in neurons.

Characterization of the rapid transcriptional response to long-term sensitization training in Aplysia californica.

Science.gov (United States)

Herdegen, Samantha; Holmes, Geraldine; Cyriac, Ashly; Calin-Jageman, Irina E; Calin-Jageman, Robert J

2014-12-01

We used a custom-designed microarray and quantitative PCR to characterize the rapid transcriptional response to long-term sensitization training in the marine mollusk Aplysia californica. Aplysia were exposed to repeated noxious shocks to one side of the body, a procedure known to induce a long-lasting, transcription-dependent increase in reflex responsiveness that is restricted to the side of training. One hour after training, pleural ganglia from the trained and untrained sides of the body were harvested; these ganglia contain the sensory nociceptors which help mediate the expression of long-term sensitization memory. Microarray analysis from 8 biological replicates suggests that long-term sensitization training rapidly regulates at least 81 transcripts. We used qPCR to test a subset of these transcripts and found that 83% were confirmed in the same samples, and 86% of these were again confirmed in an independent sample. Thus, our new microarray design shows strong convergent and predictive validity for analyzing the transcriptional correlates of memory in Aplysia. Fully validated transcripts include some previously identified as regulated in this paradigm (ApC/EBP and ApEgr) but also include novel findings. Specifically, we show that long-term sensitization training rapidly up-regulates the expression of transcripts which may encode Aplysia homologs of a C/EBPγ transcription factor, a glycine transporter (GlyT2), and a vacuolar-protein-sorting-associated protein (VPS36). Copyright © 2014 Elsevier Inc. All rights reserved.

Effect of microinjections of subunits of cAMP-dependent protein kinase on development, proliferation, and RNA synthesis in early embryos of the loach Misgurnus fossilis L

International Nuclear Information System (INIS)

Glukhov, A.I.; Benyumov, A.O.; Nesterova, M.V.; Severin, E.S.; Gazaryan, K.G.

1986-01-01

The effect of the catalytic and regulatory subunits of cAMP-dependent protein kinase type II on development, proliferation, and RNA synthesis was studied in loach embryos. It was found that injection of the catalytic subunit in a physiological concentration leads to a disturbance in the course of development and inhibits proliferation and RNA synthesis in the embryos. An increase in the concentration of this protein above the physiological level leads to death of the embryos in the first hours of development. Injection of the regulatory subunit stimulated the incorporation of labeled uridine into the acid-insoluble fraction of the embryos, beginning with the gastrula stage. The cell nuclei of loach embryos injected with subunits of protein kinase type II were transplanted into activated loach egg cells: subunits of protein kinase type I had no effect on the ability of nuclei of undetermined loach embryo cells to provide de novo development and their effect was reversible

Hippocampal Focal Knockout of CBP Affects Specific Histone Modifications, Long-Term Potentiation, and Long-Term Memory

Science.gov (United States)

Barrett, Ruth M; Malvaez, Melissa; Kramar, Eniko; Matheos, Dina P; Arrizon, Abraham; Cabrera, Sara M; Lynch, Gary; Greene, Robert W; Wood, Marcelo A

2011-01-01

To identify the role of the histone acetyltransferase (HAT) CREB-binding protein (CBP) in neurons of the CA1 region of the hippocampus during memory formation, we examine the effects of a focal homozygous knockout of CBP on histone modifications, gene expression, synaptic plasticity, and long-term memory. We show that CBP is critical for the in vivo acetylation of lysines on histones H2B, H3, and H4. CBP's homolog p300 was unable to compensate for the loss of CBP. Neurons lacking CBP maintained phosphorylation of the transcription factor CREB, yet failed to activate CREB:CBP-mediated gene expression. Loss of CBP in dorsal CA1 of the hippocampus resulted in selective impairments to long-term potentiation and long-term memory for contextual fear and object recognition. Together, these results suggest a necessary role for specific chromatin modifications, selectively mediated by CBP in the consolidation of memories. PMID:21508930

Phosphatase control of 4E-BP1 phosphorylation state is central for glycolytic regulation of retinal protein synthesis.

Science.gov (United States)

Gardner, Thomas W; Abcouwer, Steven F; Losiewicz, Mandy K; Fort, Patrice E

2015-09-15

Control of protein synthesis in insulin-responsive tissues has been well characterized, but relatively little is known about how this process is regulated in nervous tissues. The retina exhibits a relatively high protein synthesis rate, coinciding with high basal Akt and metabolic activities, with the majority of retinal ATP being derived from aerobic glycolysis. We examined the dependency of retinal protein synthesis on the Akt-mTOR signaling and glycolysis using ex vivo rat retinas. Akt inhibitors significantly reduced retinal protein synthesis but did not affect glycolytic lactate production. Surprisingly, the glycolytic inhibitor 2-deoxyglucose (2-DG) markedly inhibited Akt1 and Akt3 activities, as well as protein synthesis. The effects of 2-DG, and 2-fluorodeoxyglucose (2-FDG) on retinal protein synthesis correlated with inhibition of lactate production and diminished ATP content, with all these effects reversed by provision of d-mannose. 2-DG treatment was not associated with increased AMPK, eEF2, or eIF2α phosphorylation; instead, it caused rapid dephosphorylation of 4E-BP1. 2-DG reduced total mTOR activity by 25%, but surprisingly, it did not reduce mTORC1 activity, as indicated by unaltered raptor-associated mTOR autophosphorylation and ribosomal protein S6 phosphorylation. Dephosphorylation of 4E-BP1 was largely prevented by inhibition of PP1/PP2A phosphatases with okadaic acid and calyculin A, and inhibition of PPM1 phosphatases with cadmium. Thus, inhibition of retinal glycolysis diminished Akt and protein synthesis coinciding with accelerated dephosphorylation of 4E-BP1 independently of mTORC1. These results demonstrate a novel mechanism regulating protein synthesis in the retina involving an mTORC1-independent and phosphatase-dependent regulation of 4E-BP1. Copyright © 2015 the American Physiological Society.

Directed Evolution of Proteins through In Vitro Protein Synthesis in Liposomes

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Takehiro Nishikawa

2012-01-01

Full Text Available Directed evolution of proteins is a technique used to modify protein functions through “Darwinian selection.” In vitro compartmentalization (IVC is an in vitro gene screening system for directed evolution of proteins. IVC establishes the link between genetic information (genotype and the protein translated from the information (phenotype, which is essential for all directed evolution methods, by encapsulating both in a nonliving microcompartment. Herein, we introduce a new liposome-based IVC system consisting of a liposome, the protein synthesis using recombinant elements (PURE system and a fluorescence-activated cell sorter (FACS used as a microcompartment, in vitro protein synthesis system, and high-throughput screen, respectively. Liposome-based IVC is characterized by in vitro protein synthesis from a single copy of a gene in a cell-sized unilamellar liposome and quantitative functional evaluation of the synthesized proteins. Examples of liposome-based IVC for screening proteins such as GFP and β-glucuronidase are described. We discuss the future directions for this method and its applications.

Effect of a very low-protein diet on outcomes: long-term follow-up of the Modification of Diet in Renal Disease (MDRD) Study.

Science.gov (United States)

Menon, Vandana; Kopple, Joel D; Wang, Xuelei; Beck, Gerald J; Collins, Allan J; Kusek, John W; Greene, Tom; Levey, Andrew S; Sarnak, Mark J

2009-02-01

The long-term effect of a very low-protein diet on the progression of kidney disease is unknown. We examined the effect of a very low-protein diet on the development of kidney failure and death during long-term follow-up of the Modification of Diet in Renal Disease (MDRD) Study. Long-term follow-up of study B of the MDRD Study (1989-1993). The MDRD Study examined the effects of dietary protein restriction and blood pressure control on progression of kidney disease. This analysis includes 255 trial participants with predominantly stage 4 nondiabetic chronic kidney disease. A low-protein diet (0.58 g/kg/d) versus a very low-protein diet (0.28 g/kg/d) supplemented with a mixture of essential keto acids and amino acids (0.28 g/kg/d). Kidney failure (initiation of dialysis therapy or transplantation) and all-cause mortality until December 31, 2000. Kidney failure developed in 227 (89%) participants, 79 (30.9%) died, and 244 (95.7%) reached the composite outcome of either kidney failure or death. Median duration of follow-up until kidney failure, death, or administrative censoring was 3.2 years, and median time to death was 10.6 years. In the low-protein group, 117 (90.7%) participants developed kidney failure, 30 (23.3%) died, and 124 (96.1%) reached the composite outcome. In the very low-protein group, 110 (87.3%) participants developed kidney failure, 49 (38.9%) died, and 120 (95.2%) reached the composite outcome. After adjustment for a priori-specified covariates, hazard ratios were 0.83 (95% confidence interval, 0.62 to 1.12) for kidney failure, 1.92 (95% confidence interval, 1.15 to 3.20) for death, and 0.89 (95% confidence interval, 0.67 to 1.18) for the composite outcome in the very low-protein diet group compared with the low-protein diet group. Lack of dietary protein measurements during follow-up. In long-term follow-up of the MDRD Study, assignment to a very low-protein diet did not delay progression to kidney failure, but appeared to increase the risk of

Arraying proteins by cell-free synthesis.

Science.gov (United States)

He, Mingyue; Wang, Ming-Wei

2007-10-01

Recent advances in life science have led to great motivation for the development of protein arrays to study functions of genome-encoded proteins. While traditional cell-based methods have been commonly used for generating protein arrays, they are usually a time-consuming process with a number of technical challenges. Cell-free protein synthesis offers an attractive system for making protein arrays, not only does it rapidly converts the genetic information into functional proteins without the need for DNA cloning, but also presents a flexible environment amenable to production of folded proteins or proteins with defined modifications. Recent advancements have made it possible to rapidly generate protein arrays from PCR DNA templates through parallel on-chip protein synthesis. This article reviews current cell-free protein array technologies and their proteomic applications.

Protein synthesis in vivo during the development of various muscles in the lamb

International Nuclear Information System (INIS)

Arnal, M.; Ferrara, M.; Fauconneau, G.

1976-01-01

Protein synthesis is measured in vivo after the injection of 14 C(U) L lysine. The radioactivity incorporated in the proteins is studied as a function of the specific radioactivity of the precursor. Catabolism is estimated from the difference between real and apparent anabolism. The amount of proteins synthesized per unit weight in the tensor facialatae (TFL, the anconeus externus (AE), and the diaphragm (D) decreases rapidly until the age of 10 weeks (approximately puberty). It then levels out or increases after that age, depending on the muscle in question. The real anabolism of the white muscle (TFL) is higher than that of the red (AE and D) in one-week-old lambs. At 16 weeks, protein synthesis is higher in red muscle (D) than in white. The apparent anabolism of the muscles studied is constant during the period considered. The decrease in real anabolism per unit weight is compensated by the increased volume of the muscles, and they synthesize similar quantities of protein as long as the animal is preruminant (1-5 weeks). The protein fixation efficiency (R=ratio between apparent and real anabolism) is constant and in the neighbourhood of 20% during this period. When the animal is older, the quantity of proteins synthesized by the muscles decreases. R is variable in the ruminant animal, and increases at the age of 10 weeks, especially in white muscle, after which it decreases at the age of 16 weeks. The effect of sex hormones around puberty and the particular energy foods of the ruminant (volatile fatty acids) may explain this better efficiency. The renewal time of muscular proteins increases with age. These results facilitate understanding of the differences found in the literature in the energy cost of protein production during growth. (author)

Constitutive Activation of the G-Protein Subunit G[alpha]s within Forebrain Neurons Causes PKA-Dependent Alterations in Fear Conditioning and Cortical "Arc" mRNA Expression

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Kelly, Michele P.; Cheung, York-Fong; Favilla, Christopher; Siegel, Steven J.; Kanes, Stephen J.; Houslay, Miles D.; Abel, Ted

2008-01-01

Memory formation requires cAMP signaling; thus, this cascade has been of great interest in the search for cognitive enhancers. Given that medications are administered long-term, we determined the effects of chronically increasing cAMP synthesis in the brain by expressing a constitutively active isoform of the G-protein subunit G[alpha]s…

Preparation of ubiquitin-conjugated proteins using an insect cell-free protein synthesis system.

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Suzuki, Takashi; Ezure, Toru; Ando, Eiji; Nishimura, Osamu; Utsumi, Toshihiko; Tsunasawa, Susumu

2010-01-01

Ubiquitination is one of the most significant posttranslational modifications (PTMs). To evaluate the ability of an insect cell-free protein synthesis system to carry out ubiquitin (Ub) conjugation to in vitro translated proteins, poly-Ub chain formation was studied in an insect cell-free protein synthesis system. Poly-Ub was generated in the presence of Ub aldehyde (UA), a de-ubiquitinating enzyme inhibitor. In vitro ubiquitination of the p53 tumor suppressor protein was also analyzed, and p53 was poly-ubiquitinated when Ub, UA, and Mdm2, an E3 Ub ligase (E3) for p53, were added to the in vitro reaction mixture. These results suggest that the insect cell-free protein synthesis system contains enzymatic activities capable of carrying out ubiquitination. CBB-detectable ubiquitinated p53 was easily purified from the insect cell-free protein synthesis system, allowing analysis of the Ub-conjugated proteins by mass spectrometry (MS). Lys 305 of p53 was identified as one of the Ub acceptor sites using this strategy. Thus, we conclude that the insect cell-free protein synthesis system is a powerful tool for studying various PTMs of eukaryotic proteins including ubiqutination presented here.

Protein synthesis in x-irradiated rabbit lens

International Nuclear Information System (INIS)

Garadi, R.; Foltyn, A.R.; Giblin, F.J.; Reddy, V.N.

1984-01-01

The present study deals with the incorporation of 35 S methionine into lens crystallins as a function of time after x-irradiation. Crystallin synthesis is first affected approximately 4 weeks following x-irradiation. This coincides with the time period at which the ratio of the two cations in the lens is affected, as shown in earlier studies. A greater decrease in 35 S-methionine incorporation into crystallins is observed between 5-7 weeks following x-irradiation in good agreement with a cation imbalance at these time intervals. These studies also revealed for the first time that the change in cation distribution can affect not only crystallin synthesis, but also the synthesis of certain polypeptides of lens membranes. No alteration in protein synthesis could be detected in lens epithelium even after 7 weeks following irradiation. In addition to the effect of Na+ and K+ levels on protein synthesis, an impaired transport of amino acids into the x-rayed lens was also found to be a factor in the observed reduction in synthesis of the crystallin, cytoskeletal and membrane proteins of the fiber cells. It is concluded that Na+/K+ ratio as well as the availability of amino acids in the lens are important factors in protein synthesis of x-ray cataracts

Two waves of proteasome-dependent protein degradation in the hippocampus are required for recognition memory consolidation.

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Figueiredo, Luciana S; Dornelles, Arethuza S; Petry, Fernanda S; Falavigna, Lucio; Dargél, Vinicius A; Köbe, Luiza M; Aguzzoli, Cristiano; Roesler, Rafael; Schröder, Nadja

2015-04-01

Healthy neuronal function and synaptic modification require a concert of synthesis and degradation of proteins. Increasing evidence indicates that protein turnover mediated by proteasome activity is involved in long-term synaptic plasticity and memory. However, its role in different phases of memory remains debated, and previous studies have not examined the possible requirement of protein degradation in recognition memory. Here, we show that the proteasome inhibitor, lactacystin (LAC), infused into the CA1 area of the hippocampus at two specific time points during consolidation, impairs 24-retention of memory for object recognition in rats. Administration of LAC after retrieval did not affect retention. These findings provide the first evidence for a requirement of proteasome activity in recognition memory, indicate that protein degradation in the hippocampus is necessary during selective time windows of memory consolidation, and further our understanding of the role of protein turnover in memory formation. Copyright © 2015 Elsevier Inc. All rights reserved.

Acute inhibition of estradiol synthesis impacts vestibulo-ocular reflex adaptation and cerebellar long-term potentiation in male rats.

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Dieni, Cristina V; Ferraresi, Aldo; Sullivan, Jacqueline A; Grassi, Sivarosa; Pettorossi, Vito E; Panichi, Roberto

2018-03-01

The vestibulo-ocular reflex (VOR) adaptation is an ideal model for investigating how the neurosteroid 17 beta-estradiol (E2) contributes to the modification of behavior by regulating synaptic activities. We hypothesized that E2 impacts VOR adaptation by affecting cerebellar synaptic plasticity at the parallel fiber-Purkinje cell (PF) synapse. To verify this hypothesis, we investigated the acute effect of blocking E2 synthesis on gain increases and decreases in adaptation of the VOR in male rats using an oral dose (2.5 mg/kg) of the aromatase inhibitor letrozole. We also assessed the effect of letrozole on synaptic plasticity at the PF synapse in vitro, using cerebellar slices from male rats. We found that letrozole acutely impaired both gain increases and decreases adaptation of the VOR without altering basal ocular-motor performance. Moreover, letrozole prevented long-term potentiation at the PF synapse (PF-LTP) without affecting long-term depression (PF-LTD). Thus, in male rats neurosteroid E2 has a relevant impact on VOR adaptation and affects exclusively PF-LTP. These findings suggest that E2 might regulate changes in VOR adaptation by acting locally on cerebellar and extra-cerebellar synaptic plasticity sites.

Albumin synthesis in protein energy malnutrition

International Nuclear Information System (INIS)

Duggan, C.; Hardy, S.; Kleinman, R.E.; Lembcke, J.; Young, V.E.

1994-01-01

The dietary treatment of protein-energy malnutrition (PEM) has been designed on an empirical basis, with outcomes for successful management including body weight gain and resolution of apathy. We propose using the measurements of protein synthesis as a more objective measure of renourishment. We will therefore randomize a group of malnourished children (weigh-for-height Z score 13 C-leucine and serial measurements of 13 C-enrichment of albumin. Isotope infusions will be performed on days one and three, following a standard three hour fast. Since albumin synthesis is reduced under the influence of cytokines which mediate the inflammatory response, results will be stratified according to the presence or absence of clinically apparent infections. We hypothesize that the provision of added dietary protein will optimize albumin synthesis rates in PEM as well as attenuate the reduction in albumin synthesis seen in the presence of infections. (author). 20 refs

Mitochondrial protein acetylation mediates nutrient sensing of mitochondrial protein synthesis and mitonuclear protein balance.

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Di Domenico, Antonella; Hofer, Annette; Tundo, Federica; Wenz, Tina

2014-11-01

Changes in nutrient supply require global metabolic reprogramming to optimize the utilization of the nutrients. Mitochondria as a central component of the cellular metabolism play a key role in this adaptive process. Since mitochondria harbor their own genome, which encodes essential enzymes, mitochondrial protein synthesis is a determinant of metabolic adaptation. While regulation of cytoplasmic protein synthesis in response to metabolic challenges has been studied in great detail, mechanisms which adapt mitochondrial translation in response to metabolic challenges remain elusive. Our results suggest that the mitochondrial acetylation status controlled by Sirt3 and its proposed opponent GCN5L1 is an important regulator of the metabolic adaptation of mitochondrial translation. Moreover, both proteins modulate regulators of cytoplasmic protein synthesis as well as the mitonuclear protein balance making Sirt3 and GCN5L1 key players in synchronizing mitochondrial and cytoplasmic translation. Our results thereby highlight regulation of mitochondrial translation as a novel component in the cellular nutrient sensing scheme and identify mitochondrial acetylation as a new regulatory principle for the metabolic competence of mitochondrial protein synthesis. © 2014 International Union of Biochemistry and Molecular Biology.

Simultaneous Hypoxia and Low Extracellular pH Suppress Overall Metabolic Rate and Protein Synthesis In Vitro.

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Sørensen, Brita Singers; Busk, Morten; Overgaard, Jens; Horsman, Michael R; Alsner, Jan

2015-01-01

The tumor microenvironment is characterized by regions of hypoxia and acidosis which are linked to poor prognosis. This occurs due to an aberrant vasculature as well as high rates of glycolysis and lactate production in tumor cells even in the presence of oxygen (the Warburg effect), which weakens the spatial linkage between hypoxia and acidosis. Five different human squamous cell carcinoma cell lines (SiHa, FaDuDD, UTSCC5, UTSCC14 and UTSCC15) were treated with hypoxia, acidosis (pH 6.3), or a combination, and gene expression analyzed using microarray. SiHa and FaDuDD were chosen for further characterization of cell energetics and protein synthesis. Total cellular ATP turnover and relative glycolytic dependency was determined by simultaneous measurements of oxygen consumption and lactate synthesis rates and total protein synthesis was determined by autoradiographic quantification of the incorporation of 35S-labelled methionine and cysteine into protein. Microarray analysis allowed differentiation between genes induced at low oxygen only at normal extracellular pH (pHe), genes induced at low oxygen at both normal and low pHe, and genes induced at low pHe independent of oxygen concentration. Several genes were found to be upregulated by acidosis independent of oxygenation. Acidosis resulted in a more wide-scale change in gene expression profiles than hypoxia including upregulation of genes involved in the translation process, for example Eukaryotic translation initiation factor 4A, isoform 2 (EIF4A2), and Ribosomal protein L37 (RPL37). Acidosis suppressed overall ATP turnover and protein synthesis by 50%. Protein synthesis, but not total ATP production, was also suppressed under hypoxic conditions. A dramatic decrease in ATP turnover (SiHa) and protein synthesis (both cell lines) was observed when hypoxia and low pHe were combined. We demonstrate here that the influence of hypoxia and acidosis causes different responses, both in gene expression and in de novo

Key Markers of mTORC1-Dependent and mTORC1-Independent Signaling Pathways Regulating Protein Synthesis in Rat Soleus Muscle During Early Stages of Hindlimb Unloading.

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Mirzoev, Timur; Tyganov, Sergey; Vilchinskaya, Natalia; Lomonosova, Yulia; Shenkman, Boris

2016-01-01

The purpose of the study was to assess the amount of rRNA and phosphorylation status of the key markers of mTORC1-dependent (70s6k, 4E-BP1) and mTORC1-independent (GSK-3β, AMPK) signaling pathways controlling protein synthesis in rat soleus during early stages of mechanical unloading (hindlimb suspension (HS) for 1-, 3- and 7 days). The content of the key signaling molecules of various anabolic signaling pathways was determined by Western-blotting. The amount of 28S rRNA was evaluated by RT-PCR. The rate of protein synthesis was assessed using in-vivo SUnSET technique. HS for 3 and 7 days induced a significant (pprotein synthesis in soleus muscle in comparison with control. HS within 24 hours resulted in a significant (pprotein synthesis in rat soleus during early stages of simulated microgravity is associated with impaired ribosome biogenesis as well as reduced activity of mTORC1-independent signaling pathways. © 2016 The Author(s) Published by S. Karger AG, Basel.

Perinatal long chain polyunsaturated fatty acid supply Are there long term consequences?

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Demmelmair Hans

2007-05-01

Full Text Available Long-chain polyunsaturated fatty acids (LC-PUFA, especially docosahexaenoic acid (DHA, are essential components of biological membranes or act as precursors for eicosanoid formation, in case of the 20 carbon atom fatty acids, arachidonic acid (AA, dihomo-c-linolenic acid and eicosapentaenoic acid. During pregnancy LC-PUFA are enriched in the fetal circulation relative to maternal plasma. The corresponding placental processes have not been fully elucidated so far, but there are good indications that the LC-PUFA enrichment during the materno-fetal transfer is mediated by differences in the incorporation into lipid classes within the placenta between fatty acids and that specific fatty acid binding and transfer proteins are of major importance. In vitro a plasma membrane fatty acid binding protein could be identified, which preferentially binds DHA and AA compared to linoleic and oleic acids; in addition the m-RNA expression of fatty acid transfer protein 4 (FATP-4 in placental tissue was found to correlate significantly with the DHA percentage in cord blood phospholipids. After birth the percentage of LC-PUFA in infantile blood rapidly declines to levels depending on the dietary LC-PUFA supply, although preterm and full-term babies can convert linoleic and _-linolenic acids into AA and DHA, respectively. Breast milk provides preformed LC-PUFA, and breastfed infants have higher LC-PUFA levels in plasma and tissue than infants fed formulas without LC-PUFA. The high percentage of DHA in brain and other nervous tissue and the fact that the perinatal period is a period of fast brain growth suggests the importance of placental DHA transfer and dietary DHA content for optimal infantile development. Most but not all randomized, double blind, controlled clinical trials in preterm and in healthy full term infants demonstrated benefits of formulas supplemented with DHA and AA for the neurological development compared to formulas without LC-PUFA. Furthermore

Differences in the verbal fluency, working memory and executive functions in alcoholics: Short-term vs. long-term abstainers.

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Nowakowska-Domagała, Katarzyna; Jabłkowska-Górecka, Karolina; Mokros, Łukasz; Koprowicz, Jacek; Pietras, Tadeusz

2017-03-01

The aim of the study was to assess differences in verbal fluency, working memory and executive functions in two subgroups of alcohol-dependent patients, those undergoing short-term abstinence (STA) and those undergoing long-term abstinence (LTA), and to compare the level of cognitive functions in patients after long-term abstinence with healthy subjects. The study group consisted of 106 alcohol-dependent patients (53 immediately after drinking at least 3 days and 53 after at least one-year abstinence). The control group comprised 53 subjects, whose age, sex and education levels matched those of the patients in the experimental group. The dependence intensity was assessed using SADD and MAST scales. The neuropsychological assessment was based on the FAS Test, Stroop Test and TMT A&B Test. The results obtained for alcohol-dependent patients revealed significant disturbances of cognitive functions. Such results indicate the presence of severe frontal cerebral cortex dysfunctions. Frontal cortex dysfunctions affecting the verbal fluency and working memory subsystems and the executive functions also persisted during long-term abstinence periods. No significant correlations between the duration of dependence, quantity of alcohol consumed and efficiency of the working memory and executive functions were observed in alcohol-dependent subjects after short-term or long-term abstinence. Copyright © 2017 Elsevier Ireland Ltd. All rights reserved.

Consolidation of an olfactory memory trace in the olfactory bulb is required for learning-induced survival of adult-born neurons and long-term memory.

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Florence Kermen

Full Text Available BACKGROUND: It has recently been proposed that adult-born neurons in the olfactory bulb, whose survival is modulated by learning, support long-term olfactory memory. However, the mechanism used to select which adult-born neurons following learning will participate in the long-term retention of olfactory information is unknown. We addressed this question by investigating the effect of bulbar consolidation of olfactory learning on memory and neurogenesis. METHODOLOGY/PRINCIPAL FINDINGS: Initially, we used a behavioral ecological approach using adult mice to assess the impact of consolidation on neurogenesis. Using learning paradigms in which consolidation time was varied, we showed that a spaced (across days, but not a massed (within day, learning paradigm increased survival of adult-born neurons and allowed long-term retention of the task. Subsequently, we used a pharmacological approach to block consolidation in the olfactory bulb, consisting in intrabulbar infusion of the protein synthesis inhibitor anisomycin, and found impaired learning and no increase in neurogenesis, while basic olfactory processing and the basal rate of adult-born neuron survival remained unaffected. Taken together these data indicate that survival of adult-born neurons during learning depends on consolidation processes taking place in the olfactory bulb. CONCLUSION/SIGNIFICANCE: We can thus propose a model in which consolidation processes in the olfactory bulb determine both survival of adult-born neurons and long-term olfactory memory. The finding that adult-born neuron survival during olfactory learning is governed by consolidation in the olfactory bulb strongly argues in favor of a role for bulbar adult-born neurons in supporting olfactory memory.

Consolidation of an olfactory memory trace in the olfactory bulb is required for learning-induced survival of adult-born neurons and long-term memory.

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Kermen, Florence; Sultan, Sébastien; Sacquet, Joëlle; Mandairon, Nathalie; Didier, Anne

2010-08-13

It has recently been proposed that adult-born neurons in the olfactory bulb, whose survival is modulated by learning, support long-term olfactory memory. However, the mechanism used to select which adult-born neurons following learning will participate in the long-term retention of olfactory information is unknown. We addressed this question by investigating the effect of bulbar consolidation of olfactory learning on memory and neurogenesis. Initially, we used a behavioral ecological approach using adult mice to assess the impact of consolidation on neurogenesis. Using learning paradigms in which consolidation time was varied, we showed that a spaced (across days), but not a massed (within day), learning paradigm increased survival of adult-born neurons and allowed long-term retention of the task. Subsequently, we used a pharmacological approach to block consolidation in the olfactory bulb, consisting in intrabulbar infusion of the protein synthesis inhibitor anisomycin, and found impaired learning and no increase in neurogenesis, while basic olfactory processing and the basal rate of adult-born neuron survival remained unaffected. Taken together these data indicate that survival of adult-born neurons during learning depends on consolidation processes taking place in the olfactory bulb. We can thus propose a model in which consolidation processes in the olfactory bulb determine both survival of adult-born neurons and long-term olfactory memory. The finding that adult-born neuron survival during olfactory learning is governed by consolidation in the olfactory bulb strongly argues in favor of a role for bulbar adult-born neurons in supporting olfactory memory.

Changes in the protein patterns in pea (Pisum sativum L.) roots under the influence of long- and short-term chilling stress and post-stress recovery.

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Badowiec, Anna; Swigonska, Sylwia; Weidner, Stanisław

2013-10-01

Amongst many factors restricting geographical distribution of plants and crop productivity, low temperature is one of the most important. To gain better understanding of the molecular response of germinating pea (Pisum sativum L.) to low temperature, we investigated the influence of long and short chilling stress as well as post-stress recovery on the alterations in the root proteomes. The impact of long stress was examined on the pea seeds germinating in the continuous chilling conditions of 10 °C for 8 days (LS). To examine the impact of short stress, pea seeds germinating for 72 h in the optimal temperature of 20 °C were subjected to 24-h chilling (SS). Additionally, both stress treatments were followed by 24 h of recovery in the optimal conditions (accordingly LSR and SR). Using the 2D gel electrophoresis and MALDI-TOF MS protein identification, it was revealed, that most of the proteins undergoing regulation under the applied conditions were implicated in metabolism, protection against stress, cell cycle regulation, cell structure maintenance and hormone synthesis, which altogether may influence root growth and development in the early stages of plant life. The obtained results have shown that most of detected alterations in the proteome patterns of pea roots are dependent on stress duration. However, there are some analogical response pathways which are triggered regardless of stress length. The functions of proteins which accumulation has been changed by chilling stress and post-stress recovery are discussed here in relation to their impact on pea roots development. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

Protein chemical synthesis by α-ketoacid-hydroxylamine ligation.

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Harmand, Thibault J; Murar, Claudia E; Bode, Jeffrey W

2016-06-01

Total chemical synthesis of proteins allows researchers to custom design proteins without the complex molecular biology that is required to insert non-natural amino acids or the biocontamination that arises from methods relying on overexpression in cells. We describe a detailed procedure for the chemical synthesis of proteins with the α-ketoacid-hydroxylamine (KAHA ligation), using (S)-5-oxaproline (Opr) as a key building block. This protocol comprises two main parts: (i) the synthesis of peptide fragments by standard fluorenylmethoxycarbonyl (Fmoc) chemistry and (ii) the KAHA ligation between fragments containing Opr and a C-terminal peptide α-ketoacid. This procedure provides an alternative to native chemical ligation (NCL) that could be valuable for the synthesis of proteins, particularly targets that do not contain cysteine residues. The ligation conditions-acidic DMSO/H2O or N-methyl-2-pyrrolidinone (NMP)/H2O-are ideally suited for solubilizing peptide segments, including many hydrophobic examples. The utility and efficiency of the protocol is demonstrated by the total chemical synthesis of the mature betatrophin (also called ANGPTL8), a 177-residue protein that contains no cysteine residues. With this protocol, the total synthesis of the betatrophin protein has been achieved in around 35 working days on a multimilligram scale.

Glucose Synthesis in a Protein-Based Artificial Photosynthesis System.

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Lu, Hao; Yuan, Wenqiao; Zhou, Jack; Chong, Parkson Lee-Gau

2015-09-01

The objective of this study was to understand glucose synthesis of a protein-based artificial photosynthesis system affected by operating conditions, including the concentrations of reactants, reaction temperature, and illumination. Results from non-vesicle-based glyceraldehyde-3-phosphate (GAP) and glucose synthesis showed that the initial concentrations of ribulose-1,5-bisphosphate (RuBP) and adenosine triphosphate (ATP), lighting source, and temperature significantly affected glucose synthesis. Higher initial concentrations of RuBP and ATP significantly enhanced GAP synthesis, which was linearly correlated to glucose synthesis, confirming the proper functions of all catalyzing enzymes in the system. White fluorescent light inhibited artificial photosynthesis and reduced glucose synthesis by 79.2 % compared to in the dark. The reaction temperature of 40 °C was optimum, whereas lower or higher temperature reduced glucose synthesis. Glucose synthesis in the vesicle-based artificial photosynthesis system reconstituted with bacteriorhodopsin, F 0 F 1 ATP synthase, and polydimethylsiloxane-methyloxazoline-polydimethylsiloxane triblock copolymer was successfully demonstrated. This system efficiently utilized light-induced ATP to drive glucose synthesis, and 5.2 μg ml(-1) glucose was synthesized in 0.78-ml reaction buffer in 7 h. Light-dependent reactions were found to be the bottleneck of the studied artificial photosynthesis system.

Do serotonin(1-7) receptors modulate short and long-term memory?

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Meneses, A

2007-05-01

Evidence from invertebrates to human studies indicates that serotonin (5-hydroxytryptamine; 5-HT) system modulates short- (STM) and long-term memory (LTM). This work is primarily focused on analyzing the contribution of 5-HT, cholinergic and glutamatergic receptors as well as protein synthesis to STM and LTM of an autoshaping learning task. It was observed that the inhibition of hippocampal protein synthesis or new mRNA did not produce a significant effect on autoshaping STM performance but it did impair LTM. Both non-contingent protein inhibition and 5-HT depletion showed no effects. It was basically the non-selective 5-HT receptor antagonist cyproheptadine, which facilitated STM. However, the blockade of glutamatergic and cholinergic transmission impaired STM. In contrast, the selective 5-HT(1B) receptor antagonist SB-224289 facilitated both STM and LTM. Selective receptor antagonists for the 5-HT(1A) (WAY100635), 5-HT(1D) (GR127935), 5-HT(2A) (MDL100907), 5-HT(2C/2B) (SB-200646), 5-HT(3) (ondansetron) or 5-HT(4) (GR125487), 5-HT(6) (Ro 04-6790, SB-399885 and SB-35713) or 5-HT(7) (SB-269970) did not impact STM. Nevertheless, WAY100635, MDL100907, SB-200646, GR125487, Ro 04-6790, SB-399885 or SB-357134 facilitated LTM. Notably, some of these changes shown to be independent of food-intake. Concomitantly, these data indicate that '5-HT tone via 5-HT(1B) receptors' might function in a serial manner from STM to LTM, whereas working in parallel using 5-HT(1A), 5-HT(2A), 5-HT(2B/2C), 5-HT(4), or 5-HT(6) receptors.

The flavoprotein Tah18-dependent NO synthesis confers high-temperature stress tolerance on yeast cells

International Nuclear Information System (INIS)

Nishimura, Akira; Kawahara, Nobuhiro; Takagi, Hiroshi

2013-01-01

Highlights: ► NO is produced from L-arginine in response to elevated temperature in yeast. ► Tah18 was first identified as the yeast protein involved in NO synthesis. ► Tah18-dependent NO synthesis confers tolerance to high-temperature on yeast cells. -- Abstract: Nitric oxide (NO) is a ubiquitous signaling molecule involved in the regulation of a large number of cellular functions. In the unicellular eukaryote yeast, NO may be involved in stress response pathways, but its role is poorly understood due to the lack of mammalian NO synthase (NOS) orthologues. Previously, we have proposed the oxidative stress-induced L-arginine synthesis and its physiological role under stress conditions in yeast Saccharomyces cerevisiae. Here, our experimental results indicated that increased conversion of L-proline into L-arginine led to NO production in response to elevated temperature. We also showed that the flavoprotein Tah18, which was previously reported to transfer electrons to the Fe–S cluster protein Dre2, was involved in NO synthesis in yeast. Gene knockdown analysis demonstrated that Tah18-dependent NO synthesis confers high-temperature stress tolerance on yeast cells. As it appears that such a unique cell protection mechanism is specific to yeasts and fungi, it represents a promising target for antifungal activity.

Converting a Natural Protein Compartment into a Nanofactory for the Size-Constrained Synthesis of Antimicrobial Silver Nanoparticles.

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Giessen, Tobias W; Silver, Pamela A

2016-12-16

Engineered biological systems are used extensively for the production of high value and commodity organics. On the other hand, most inorganic nanomaterials are still synthesized via chemical routes. By engineering cellular compartments, functional nanoarchitectures can be produced under environmentally sustainable conditions. Encapsulins are a new class of microbial nanocompartments with promising applications in nanobiotechnology. Here, we engineer the Thermotoga maritima encapsulin EncTm to yield a designed compartment for the size-constrained synthesis of silver nanoparticles (Ag NPs). These Ag NPs exhibit uniform shape and size distributions as well as long-term stability. Ambient aqueous conditions can be used for Ag NP synthesis, while no reducing agents or solvents need to be added. The antimicrobial activity of the synthesized protein-coated or shell-free Ag NPs is superior to that of silver nitrate and citrate-capped Ag NPs. This study establishes encapsulins as an engineerable platform for the synthesis of biogenic functional nanomaterials.

Antihypertensive Properties of a Pea Protein Hydrolysate during Short- and Long-Term Oral Administration to Spontaneously Hypertensive Rats.

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Girgih, Abraham T; Nwachukwu, Ifeanyi D; Onuh, John O; Malomo, Sunday A; Aluko, Rotimi E

2016-05-01

This study investigated short-term (24 h) and long-term (5 wk) systolic blood pressure (SBP)-lowering effects in spontaneously hypertensive rats (SHR) of a 5 kDa membrane pea protein hydrolysate permeate (PPH-5) produced through thermoase hydrolysis of pea protein isolate (PPI). Amino acid analysis showed that the PPH-5 had lower contents of sulfur-containing amino acids than the PPI. Size-exclusion chromatography indicated mainly low molecular weight (pea products decreased in the 4th and 5th wk, though SBP values of the treated rats were still lower than the untreated control. We conclude that the antihypertensive potency of PPH-5 may have been due to the presence of easily absorbed hydrophilic peptides. © 2016 Institute of Food Technologists®

Short and long-lasting behavioral consequences of agonistic encounters between male Drosophila melanogaster.

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Trannoy, Séverine; Penn, Jill; Lucey, Kenia; Popovic, David; Kravitz, Edward A

2016-04-26

In many animal species, learning and memory have been found to play important roles in regulating intra- and interspecific behavioral interactions in varying environments. In such contexts, aggression is commonly used to obtain desired resources. Previous defeats or victories during aggressive interactions have been shown to influence the outcome of later contests, revealing loser and winner effects. In this study, we asked whether short- and/or long-term behavioral consequences accompany victories and defeats in dyadic pairings between male Drosophila melanogaster and how long those effects remain. The results demonstrated that single fights induced important behavioral changes in both combatants and resulted in the formation of short-term loser and winner effects. These decayed over several hours, with the duration depending on the level of familiarity of the opponents. Repeated defeats induced a long-lasting loser effect that was dependent on de novo protein synthesis, whereas repeated victories had no long-term behavioral consequences. This suggests that separate mechanisms govern the formation of loser and winner effects. These studies aim to lay a foundation for future investigations exploring the molecular mechanisms and circuitry underlying the nervous system changes induced by winning and losing bouts during agonistic encounters.

Loss of long-term depression in the insular cortex after tail amputation in adult mice.

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Liu, Ming-Gang; Zhuo, Min

2014-01-08

The insular cortex (IC) is an important forebrain structure involved in pain perception and taste memory formation. Using a 64-channel multi-electrode array system, we recently identified and characterized two major forms of synaptic plasticity in the adult mouse IC: long-term potentiation (LTP) and long-term depression (LTD). In this study, we investigate injury-related metaplastic changes in insular synaptic plasticity after distal tail amputation. We found that tail amputation in adult mice produced a selective loss of low frequency stimulation-induced LTD in the IC, without affecting (RS)-3,5-dihydroxyphenylglycine (DHPG)-evoked LTD. The impaired insular LTD could be pharmacologically rescued by priming the IC slices with a lower dose of DHPG application, a form of metaplasticity which involves activation of protein kinase C but not protein kinase A or calcium/calmodulin-dependent protein kinase II. These findings provide important insights into the synaptic mechanisms of cortical changes after peripheral amputation and suggest that restoration of insular LTD may represent a novel therapeutic strategy against the synaptic dysfunctions underlying the pathophysiology of phantom pain.

Effects of Whey, Caseinate, or Milk Protein Ingestion on Muscle Protein Synthesis after Exercise.

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Kanda, Atsushi; Nakayama, Kyosuke; Sanbongi, Chiaki; Nagata, Masashi; Ikegami, Shuji; Itoh, Hiroyuki

2016-06-03

Whey protein (WP) is characterized as a "fast" protein and caseinate (CA) as a "slow" protein according to their digestion and absorption rates. We hypothesized that co-ingestion of milk proteins (WP and CA) may be effective for prolonging the muscle protein synthesis response compared to either protein alone. We therefore compared the effect of ingesting milk protein (MP) to either WP or CA alone on muscle protein synthesis after exercise in rats. We also compared the effects of these milk-derived proteins to a control, soy protein (SP). Male Sprague-Dawley rats swam for two hours. Immediately after exercise, one of the following four solutions was administered: WP, CA, MP, or SP. Individual rats were euthanized at designated postprandial time points and triceps muscle samples collected for measurement of the protein fractional synthesis rate (FSR). FSR tended to increase in all groups post-ingestion, although the initial peaks of FSR occurred at different times (WP, peak time = 60 min, FSR = 7.76%/day; MP, peak time = 90 min, FSR = 8.34%/day; CA, peak time = 120 min, FSR = 7.85%/day). Milk-derived proteins caused significantly greater increases (p protein synthesis to occur at different times (WP, fast; MP, intermediate; CA, slow) and the dairy proteins have a superior effect on muscle protein synthesis after exercise compared with SP.

Conditioned taste aversion memory and c-Fos induction are disrupted in RIIbeta-protein kinase A mutant mice.

Science.gov (United States)

Koh, Ming Teng; Clarke, Sharon N D A; Spray, Kristina J; Thiele, Todd E; Bernstein, Ilene L

2003-07-14

The cAMP-dependent protein kinase (PKA) signaling pathway has been implicated in many forms of learning. The present studies examined conditioned taste aversion (CTA) learning, an amygdala-dependent task, in mice with a targeted disruption of a gene for a specific regulatory subunit of PKA (RIIbeta), which is selectively expressed in amygdala. Null mutant (RIIbeta(-/-)) mice and littermate controls (RIIbeta(+/+)) were tested for protein synthesis-independent short-term memory (STM) and protein synthesis-dependent long-term memory (LTM) for CTAs. The ability of the unconditioned stimulus (US) drug, LiCl, to induce c-Fos in regions thought to be important in this learning was also determined. RIIbeta(-/-) mice showed significant impairment in CTA memory when tested 24h after training (LTM). In contrast, STM was normal. With regard to the c-Fos response to LiCl, the US drug, significant elevations were evident in brainstem (nucleus of the solitary tract) and pontine (parabrachial nucleus) regions, in mutants as well as wild-type controls. However, in amygdala, elevations were seen in controls but were absent in the mutants. These findings suggest that disruption of PKA signaling interferes with LTM consolidation of CTA and that a possible mediator of this effect is interference with c-Fos expression in amygdala which may be necessary for CTA memory.

A protein-dependent side-chain rotamer library.

KAUST Repository

Bhuyan, M.S.; Gao, Xin

2011-01-01

Protein side-chain packing problem has remained one of the key open problems in bioinformatics. The three main components of protein side-chain prediction methods are a rotamer library, an energy function and a search algorithm. Rotamer libraries summarize the existing knowledge of the experimentally determined structures quantitatively. Depending on how much contextual information is encoded, there are backbone-independent rotamer libraries and backbone-dependent rotamer libraries. Backbone-independent libraries only encode sequential information, whereas backbone-dependent libraries encode both sequential and locally structural information. However, side-chain conformations are determined by spatially local information, rather than sequentially local information. Since in the side-chain prediction problem, the backbone structure is given, spatially local information should ideally be encoded into the rotamer libraries. In this paper, we propose a new type of backbone-dependent rotamer library, which encodes structural information of all the spatially neighboring residues. We call it protein-dependent rotamer libraries. Given any rotamer library and a protein backbone structure, we first model the protein structure as a Markov random field. Then the marginal distributions are estimated by the inference algorithms, without doing global optimization or search. The rotamers from the given library are then re-ranked and associated with the updated probabilities. Experimental results demonstrate that the proposed protein-dependent libraries significantly outperform the widely used backbone-dependent libraries in terms of the side-chain prediction accuracy and the rotamer ranking ability. Furthermore, without global optimization/search, the side-chain prediction power of the protein-dependent library is still comparable to the global-search-based side-chain prediction methods.

A protein-dependent side-chain rotamer library.

KAUST Repository

Bhuyan, M.S.

2011-12-14

Protein side-chain packing problem has remained one of the key open problems in bioinformatics. The three main components of protein side-chain prediction methods are a rotamer library, an energy function and a search algorithm. Rotamer libraries summarize the existing knowledge of the experimentally determined structures quantitatively. Depending on how much contextual information is encoded, there are backbone-independent rotamer libraries and backbone-dependent rotamer libraries. Backbone-independent libraries only encode sequential information, whereas backbone-dependent libraries encode both sequential and locally structural information. However, side-chain conformations are determined by spatially local information, rather than sequentially local information. Since in the side-chain prediction problem, the backbone structure is given, spatially local information should ideally be encoded into the rotamer libraries. In this paper, we propose a new type of backbone-dependent rotamer library, which encodes structural information of all the spatially neighboring residues. We call it protein-dependent rotamer libraries. Given any rotamer library and a protein backbone structure, we first model the protein structure as a Markov random field. Then the marginal distributions are estimated by the inference algorithms, without doing global optimization or search. The rotamers from the given library are then re-ranked and associated with the updated probabilities. Experimental results demonstrate that the proposed protein-dependent libraries significantly outperform the widely used backbone-dependent libraries in terms of the side-chain prediction accuracy and the rotamer ranking ability. Furthermore, without global optimization/search, the side-chain prediction power of the protein-dependent library is still comparable to the global-search-based side-chain prediction methods.

Hippocampal Protein Kinase C Signaling Mediates the Short-Term Memory Impairment Induced by Delta9-Tetrahydrocannabinol.

Science.gov (United States)

Busquets-Garcia, Arnau; Gomis-González, Maria; Salgado-Mendialdúa, Victòria; Galera-López, Lorena; Puighermanal, Emma; Martín-García, Elena; Maldonado, Rafael; Ozaita, Andrés

2018-04-01

Cannabis affects cognitive performance through the activation of the endocannabinoid system, and the molecular mechanisms involved in this process are poorly understood. Using the novel object-recognition memory test in mice, we found that the main psychoactive component of cannabis, delta9-tetrahydrocannabinol (THC), alters short-term object-recognition memory specifically involving protein kinase C (PKC)-dependent signaling. Indeed, the systemic or intra-hippocampal pre-treatment with the PKC inhibitors prevented the short-term, but not the long-term, memory impairment induced by THC. In contrast, systemic pre-treatment with mammalian target of rapamycin complex 1 inhibitors, known to block the amnesic-like effects of THC on long-term memory, did not modify such a short-term cognitive deficit. Immunoblot analysis revealed a transient increase in PKC signaling activity in the hippocampus after THC treatment. Thus, THC administration induced the phosphorylation of a specific Ser residue in the hydrophobic-motif at the C-terminal tail of several PKC isoforms. This significant immunoreactive band that paralleled cognitive performance did not match in size with the major PKC isoforms expressed in the hippocampus except for PKCθ. Moreover, THC transiently enhanced the phosphorylation of the postsynaptic calmodulin-binding protein neurogranin in a PKC dependent manner. These data demonstrate that THC alters short-term object-recognition memory through hippocampal PKC/neurogranin signaling.

Protein synthesis and the recovery of both survival and cytoplasmic "petite" mutation in ultraviolet-treated yeast cells. I. Nuclear-directed protein synthesis.

Science.gov (United States)

Heude, M; Chanet, R; Moustacchi, E

1975-04-01

The contribution of nuclear-directed protein synthesis in the repair of lethal and mitochondrial genetic damage after UV-irradiation of exponential and stationary phage haploid yeast cells was examined. This was carried out using cycloheximide (CH), a specific inhibitor of nuclear protein synthesis. It appears that nuclear protein synthesis is required for the increase in survival seen after the liquid holding of cells at both stages, as well as for the "petite" recovery seen after the liquid holding of exponential phase cells. The characteristic negative liquid holding effect observed for the UV induction of "petites" in stationary phase cells (increase of the frequency of "petites" during storage) remained following all the treatments which inhibited nuclear protein synthesis. However, the application of photoreactivating light following dark holding with cycloheximide indicates that some steps of the repair of both nuclear and mitochondrial damage are performed in the absence of a synthesis of proteins.

Synthesis and phosphorylation of histones and nonhistone proteins in the cycloheximide-synchronized hepatocytes after the effect of radiation and serotonin

International Nuclear Information System (INIS)

Aslamova, L.I.; Blyum, Ya.B.; Tsudzevich, B.A.; Kucherenko, N.E.

1984-01-01

Phosphorylation and synthesis of histones and nonhistone proteins were studied after the inhibition of translation by sublethal cycloheximide doses. Activation of the chromatin protein phosphorylation was noted: (1) at the stage of recovery and stimulation of the protein synthesis (18-24 h), and (2) at the stage of activation of the replicative DNA synthesis (30-60 h). Phosphorylation and synthesis of the chromatin poteins depended upon the individual or combined effect of X-radiation and serotonin. The possible role of the chromatin protein phosphorylation in the response of the nuclear apparatus to the effect of radiation and serotonin the latter being used as a radioprotective agent is discussed

Protein Synthesis Inhibition Blocks Consolidation of an Acrobatic Motor Skill

Science.gov (United States)

Kaelin-Lang, Alain; Dichgans, Johannes; Schulz, Jorg B.; Luft, Andreas R.; Buitrago, Manuel M.

2004-01-01

To investigate whether motor skill learning depends on de novo protein synthesis, adult rats were trained in an acrobatic locomotor task (accelerating rotarod) for 7 d. Animals were systemically injected with cycloheximide (CHX, 0.5 mg/kg, i.p.) 1 h before sessions 1 and 2 or sessions 2 and 3. Control rats received vehicle injections before…

Temporal phases of activity-dependent plasticity and memory are mediated by compartmentalized routing of MAPK signaling in aplysia sensory neurons.

Science.gov (United States)

Shobe, Justin L; Zhao, Yali; Stough, Shara; Ye, Xiaojing; Hsuan, Vickie; Martin, Kelsey C; Carew, Thomas J

2009-01-15

An activity-dependent form of intermediate memory (AD-ITM) for sensitization is induced in Aplysia by a single tail shock that gives rise to plastic changes (AD-ITF) in tail sensory neurons (SNs) via the interaction of action potential firing in the SN coupled with the release of serotonin in the CNS. Activity-dependent long-term facilitation (AD-LTF, lasting >24hr) requires protein synthesis dependent persistent mitogen-activated protein kinase (MAPK) activation and translocation to the SN nucleus. We now show that the induction of the earlier temporal phase (AD-ITM and AD-ITF), which is translation and transcription independent, requires the activation of a compartmentally distinct novel signaling cascade that links second messengers, MAPK and PKC into a unified pathway within tail SNs. Since both AD-ITM and AD-LTM require MAPK activity, these collective findings suggest that presynaptic SNs route the flow of molecular information to distinct subcellular compartments during the induction of activity-dependent long-lasting memories.

Conformational co-dependence between Plasmodium berghei LCCL proteins promotes complex formation and stability.

Science.gov (United States)

Saeed, Sadia; Tremp, Annie Z; Dessens, Johannes T

2012-10-01

Malaria parasites express a conserved family of LCCL-lectin adhesive-like domain proteins (LAPs) that have essential functions in sporozoite transmission. In Plasmodium falciparum all six family members are expressed in gametocytes and form a multi-protein complex. Intriguingly, knockout of P. falciparum LCCL proteins adversely affects expression of other family members at protein, but not at mRNA level, a phenomenon termed co-dependent expression. Here, we investigate this in Plasmodium berghei by crossing a PbLAP1 null mutant parasite with a parasite line expressing GFP-tagged PbLAP3 that displays strong fluorescence in gametocytes. Selected and validated double mutants show normal synthesis and subcellular localization of PbLAP3::GFP. However, GFP-based fluorescence is dramatically reduced without PbLAP1 present, indicating that PbLAP1 and PbLAP3 interact. Moreover, absence of PbLAP1 markedly reduces the half-life of PbLAP3, consistent with a scenario of misfolding. These findings unveil a potential mechanism of conformational interdependence that facilitates assembly and stability of the functional LCCL protein complex. Copyright © 2012 Elsevier B.V. All rights reserved.

Evaluation of short-term and long-term stability of emulsions by centrifugation and NMR

International Nuclear Information System (INIS)

Tcholakova, S.; Denkov, N.; Ivanov, I.; Marinov, R.

2004-01-01

The effect of storage time on the coalescence stability and drop size distribution of egg yolk and whey protein concentrate stabilized emulsions is studied. The emulsion stability is evaluated by centrifugation, whereas the drop size distribution is measured by means of NMR and optical microscopy. The experimental results show that there is no general relation between the emulsion stability and the changes in the mean drop diameter upon shelf-storage of protein emulsions. On the other hand, it is shown that the higher short-term stability, measured by centrifugation immediately after emulsion preparation, corresponds to higher long-term stability (after their self-storage up to 60 days) for emulsions stabilized by the same type of emulsifier. In this way, we are able to obtain information for the long-term stability of emulsions in a relatively short period of time.(authors)

Estrogen Regulates Protein Synthesis and Actin Polymerization in Hippocampal Neurons through Different Molecular Mechanisms

Science.gov (United States)

Briz, Victor; Baudry, Michel

2014-01-01

Estrogen rapidly modulates hippocampal synaptic plasticity by activating selective membrane-associated receptors. Reorganization of the actin cytoskeleton and stimulation of mammalian target of rapamycin (mTOR)-mediated protein synthesis are two major events required for the consolidation of hippocampal long-term potentiation and memory. Estradiol regulates synaptic plasticity by interacting with both processes, but the underlying molecular mechanisms are not yet fully understood. Here, we used acute rat hippocampal slices to analyze the mechanisms underlying rapid changes in mTOR activity and actin polymerization elicited by estradiol. Estradiol-induced mTOR phosphorylation was preceded by rapid and transient activation of both extracellular signal-regulated kinase (ERK) and protein kinase B (Akt) and by phosphatase and tensin homolog (PTEN) degradation. These effects were prevented by calpain and ERK inhibitors. Estradiol-induced mTOR stimulation did not require activation of classical estrogen receptors (ER), as specific ERα and ERβ agonists (PPT and DPN, respectively) failed to mimic this effect, and ER antagonists could not block it. Estradiol rapidly activated both RhoA and p21-activated kinase (PAK). Furthermore, a specific inhibitor of RhoA kinase (ROCK), H1152, and a potent and specific PAK inhibitor, PF-3758309, blocked estradiol-induced cofilin phosphorylation and actin polymerization. ER antagonists also blocked these effects of estrogen. Consistently, both PPT and DPN stimulated PAK and cofilin phosphorylation as well as actin polymerization. Finally, the effects of estradiol on actin polymerization were insensitive to protein synthesis inhibitors, but its stimulation of mTOR activity was impaired by latrunculin A, a drug that disrupts actin filaments. Taken together, our results indicate that estradiol regulates local protein synthesis and cytoskeletal reorganization via different molecular mechanisms and signaling pathways. PMID:24611062

Optimal Long-Term Financial Contracting

OpenAIRE

Peter M. DeMarzo; Michael J. Fishman

2007-01-01

We develop an agency model of financial contracting. We derive long-term debt, a line of credit, and equity as optimal securities, capturing the debt coupon and maturity; the interest rate and limits on the credit line; inside versus outside equity; dividend policy; and capital structure dynamics. The optimal debt-equity ratio is history dependent, but debt and credit line terms are independent of the amount financed and, in some cases, the severity of the agency problem. In our model, the ag...

Protein quality control in protection against systolic overload cardiomyopathy: the long term role of small heat shock proteins.

Science.gov (United States)

Kumarapeli, Asangi R K; Horak, Kathleen; Wang, Xuejun

2010-07-21

Molecular chaperones represent the first line of defense of intracellular protein quality control. As a major constituent of molecular chaperones, heat shock proteins (HSP) are known to confer cardiomyocyte short-term protection against various insults and injuries. Previously, we reported that the small HSP alphaB-crystallin (CryAB) attenuates cardiac hypertrophic response in mice subjected to 2 weeks of severe pressure overload. However, the long-term role of small HSPs in cardiac hypertrophy and failure has rarely been studied. The present study investigates the cardiac responses to chronic severe pressure overload in CryAB/HSPB2 germ line ablated (KO) and cardiac-specific CryAB overexpressingtransgenic (TG) mice. Pressure overload was induced by transverse aortic constriction in KO, TG, and non-transgenic wild type (NTG) control mice and 10 weeks later molecular, cellular, and whole organ level hypertrophic responses were analyzed. As we previously described, CryAB/HSPB2 KO mice showed abnormal baseline cardiac physiology that worsened into a restrictive cardiomyopathic phenotype with aging. Severe pressure overload in these mice led to rapid deterioration of heart function and development of congestive cardiac failure. Contrary to their short term protective phenotype, CryAB TG mice showed no significant effects on cardiac hypertrophic responses and very modest improvement of hemodynamics during chronic systolic overload. These findings indicate that small HSPs CryAB and/or HSPB2 are essential to maintain cardiac structure and function but overex-pression of CryAB is not sufficient to confer a sustained protection against chronic systolic overload.

5-Bromo-2'-deoxyuridine impairs long-term food aversion memory in edible snail.

Science.gov (United States)

Efimova, O I; Anokhin, K V

2012-09-01

We studied the involvement of DNA synthesis into molecular mechanisms of long-term memory. Nucleoside analogue 5-bromo-2'-deoxyuridine (BrdU) is known to incorporate into synthesizing DNA and prevent subsequent DNA replication from this region. To investigate the effect of BrdU administration on long-term memory, terrestrial gastropods edible snails Helix lucorum were trained in the food aversion paradigm. Single-session training (carrot presentation combined with application of 10% quinine solution, three carrot presentations with 10-min intervals) resulted in the formation of long-term memory that persisted for at least 45° days. BrdU administration (250 mg/kg) 30 min before training impaired long-term memory tested 24 h later. Immunohistochemical study revealed BrdU incorporation in the nuclei of identified neurons of defensive behavior.

Insulin receptors mediate growth effects in cultured fetal neurons. I. Rapid stimulation of protein synthesis

International Nuclear Information System (INIS)

Heidenreich, K.A.; Toledo, S.P.

1989-01-01

In this study we have examined the effects of insulin on protein synthesis in cultured fetal chick neurons. Protein synthesis was monitored by measuring the incorporation of [3H]leucine (3H-leu) into trichloroacetic acid (TCA)-precipitable protein. Upon addition of 3H-leu, there was a 5-min lag before radioactivity occurred in protein. During this period cell-associated radioactivity reached equilibrium and was totally recovered in the TCA-soluble fraction. After 5 min, the incorporation of 3H-leu into protein was linear for 2 h and was inhibited (98%) by the inclusion of 10 micrograms/ml cycloheximide. After 24 h of serum deprivation, insulin increased 3H-leu incorporation into protein by approximately 2-fold. The stimulation of protein synthesis by insulin was dose dependent (ED50 = 70 pM) and seen within 30 min. Proinsulin was approximately 10-fold less potent than insulin on a molar basis in stimulating neuronal protein synthesis. Insulin had no effect on the TCA-soluble fraction of 3H-leu at any time and did not influence the uptake of [3H]aminoisobutyric acid into neurons. The isotope ratio of 3H-leu/14C-leu in the leucyl tRNA pool was the same in control and insulin-treated neurons. Analysis of newly synthesized proteins by sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed that insulin uniformly increased the incorporation of 14C-leu into all of the resolved neuronal proteins. We conclude from these data that (1) insulin rapidly stimulates overall protein synthesis in fetal neurons independent of amino acid uptake and aminoacyl tRNA precursor pools; (2) stimulation of protein synthesis is mediated by the brain subtype of insulin receptor; and (3) insulin is potentially an important in vivo growth factor for fetal central nervous system neurons

Fatty-acid binding proteins modulate sleep and enhance long-term memory consolidation in Drosophila.

Directory of Open Access Journals (Sweden)

Jason R Gerstner

2011-01-01

Full Text Available Sleep is thought to be important for memory consolidation, since sleep deprivation has been shown to interfere with memory processing. However, the effects of augmenting sleep on memory formation are not well known, and testing the role of sleep in memory enhancement has been limited to pharmacological and behavioral approaches. Here we test the effect of overexpressing the brain-type fatty acid binding protein (Fabp7 on sleep and long-term memory (LTM formation in Drosophila melanogaster. Transgenic flies carrying the murine Fabp7 or the Drosophila homologue dFabp had reduced baseline sleep but normal LTM, while Fabp induction produced increases in both net sleep and LTM. We also define a post-training consolidation "window" that is sufficient for the observed Fabp-mediated memory enhancement. Since Fabp overexpression increases consolidated daytime sleep bouts, these data support a role for longer naps in improving memory and provide a novel role for lipid-binding proteins in regulating memory consolidation concurrently with changes in behavioral state.

Loss of FMRP Impaired Hippocampal Long-Term Plasticity and Spatial Learning in Rats

Directory of Open Access Journals (Sweden)

Yonglu Tian

2017-08-01

Full Text Available Fragile X syndrome (FXS is a neurodevelopmental disorder caused by mutations in the FMR1 gene that inactivate expression of the gene product, the fragile X mental retardation 1 protein (FMRP. In this study, we used clustered regularly interspaced short palindromic repeats (CRISPR/CRISPR-associated protein 9 (Cas9 technology to generate Fmr1 knockout (KO rats by disruption of the fourth exon of the Fmr1 gene. Western blotting analysis confirmed that the FMRP was absent from the brains of the Fmr1 KO rats (Fmr1exon4-KO. Electrophysiological analysis revealed that the theta-burst stimulation (TBS–induced long-term potentiation (LTP and the low-frequency stimulus (LFS–induced long-term depression (LTD were decreased in the hippocampal Schaffer collateral pathway of the Fmr1exon4-KO rats. Short-term plasticity, measured as the paired-pulse ratio, remained normal in the KO rats. The synaptic strength mediated by the α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPAR was also impaired. Consistent with previous reports, the Fmr1exon4-KO rats demonstrated an enhanced 3,5-dihydroxyphenylglycine (DHPG–induced LTD in the present study, and this enhancement is insensitive to protein translation. In addition, the Fmr1exon4-KO rats showed deficits in the probe trial in the Morris water maze test. These results demonstrate that deletion of the Fmr1 gene in rats specifically impairs long-term synaptic plasticity and hippocampus-dependent learning in a manner resembling the key symptoms of FXS. Furthermore, the Fmr1exon4-KO rats displayed impaired social interaction and macroorchidism, the results consistent with those observed in patients with FXS. Thus, Fmr1exon4-KO rats constitute a novel rat model of FXS that complements existing mouse models.

Synthesis on the long term behavior of spent nuclear fuel. Vol.1,2

International Nuclear Information System (INIS)

Poinssot, Ch.; Toulhoat, P.; Grouiller, J.P.; Pavageau, J.; Piron, J.P.; Pelletier, M.; Dehaudt, Ph.; Cappelaere, Ch.; Limon, R.; Desgranges, L.; Jegou, Ch.; Corbel, C.; Maillard, S.; Faure, M.H.; Cicariello, J.C.; Masson, M.

2001-01-01

The aim of this report is to present the major objectives, the key scientific issues, and the preliminary results of the research conducted in France in the framework of the third line of the 1991 Law, on the topic of the long term behavior of spent nuclear fuel in view of long term storage or geological disposal. Indeed, CEA launched in 1998 the Research Program on the Long Term Behavior of Spent Nuclear Fuel (abbreviated and referred to as PRECCI in French; Poinssot, 1998) the aim of which is to study and assess the ability of spent nuclear fuel packages to keep their initially allocated functions in interim storage and geological disposal: total containment and recovery functions for duration up to hundreds of years (long term or short-term interim storage and/or first reversible stages of geological disposal) and partial confinement function (controlled fluxes of RN) for thousands of years in geological disposal. This program has to allow to obtain relevant and reliable data concerning the long term behavior of the spent fuel packages so that feasibility of interim storage and/or geological disposal can be assessed and demonstrated as well as optimized. Within this framework, this report presents for every possible scenario of evolution (closed system, in Presence of water in presence of gases) what are estimated to be the most relevant evolution mechanism. For the most relevant scientific issues hence defined, a complete scientific review of the best state of knowledge is subsequently here given thus allowing to draw a clear guideline of the major R and D issues for the next years. (authors)

Effect of short-term heart rate variability biofeedback on long-term abstinence in alcohol dependent patients - a one-year follow-up.

Science.gov (United States)

Penzlin, Ana Isabel; Barlinn, Kristian; Illigens, Ben Min-Woo; Weidner, Kerstin; Siepmann, Martin; Siepmann, Timo

2017-09-06

A randomized controlled study (RCT) recently showed that short-term heart rate variability (HRV) biofeedback in addition to standard rehabilitation care for alcohol dependence can reduce craving, anxiety and improve cardiovascular autonomic function. In this one-year follow-up study we aimed to explore whether completion of 2-week HRV-Biofeedback training is associated with long-term abstinence. Furthermore, we sought to identify potential predictors of post-treatment abstinence. We conducted a survey on abstinence in patients with alcohol dependence 1 year after completion of an RCT comparing HRV-biofeedback in addition to inpatient rehabilitation treatment alone (controls). Abstinence rates were compared and analysed for association with demographic data as well as psychometric and autonomic cardiac assessment before and after completion of the biofeedback training using bivariate and multivariate regression analyses. Out of 48 patients who participated in the RCT, 27 patients (9 females, ages 42.9 ± 8.6, mean ± SD) completed our one-year follow-up. When including in the analysis only patients who completed follow-up, the rate of abstinence tended to be higher in patients who underwent HRV-biofeedback 1 year earlier compared to those who received rehabilitative treatment alone (66.7% vs 50%, p = ns). This non-significant trend was also observed in the intention-to-treat analysis where patients who did not participate in the follow-up were assumed to have relapsed (46,7% biofeedback vs. 33.3% controls, p = ns). Neither cardiac autonomic function nor psychometric variables were associated with abstinence 1 year after HRV-biofeedback. Our follow-up study provide a first indication of possible increase in long-term abstinence after HRV-biofeedback for alcohol dependence in addition to rehabilitation. The original randomized controlled trial was registered in the German Clinical Trials Register ( DRKS00004618 ). This one-year follow-up survey has not been

Simultaneous Hypoxia and Low Extracellular pH Suppress Overall Metabolic Rate and Protein Synthesis In Vitro.

Directory of Open Access Journals (Sweden)

Brita Singers Sørensen

Full Text Available The tumor microenvironment is characterized by regions of hypoxia and acidosis which are linked to poor prognosis. This occurs due to an aberrant vasculature as well as high rates of glycolysis and lactate production in tumor cells even in the presence of oxygen (the Warburg effect, which weakens the spatial linkage between hypoxia and acidosis.Five different human squamous cell carcinoma cell lines (SiHa, FaDuDD, UTSCC5, UTSCC14 and UTSCC15 were treated with hypoxia, acidosis (pH 6.3, or a combination, and gene expression analyzed using microarray. SiHa and FaDuDD were chosen for further characterization of cell energetics and protein synthesis. Total cellular ATP turnover and relative glycolytic dependency was determined by simultaneous measurements of oxygen consumption and lactate synthesis rates and total protein synthesis was determined by autoradiographic quantification of the incorporation of 35S-labelled methionine and cysteine into protein.Microarray analysis allowed differentiation between genes induced at low oxygen only at normal extracellular pH (pHe, genes induced at low oxygen at both normal and low pHe, and genes induced at low pHe independent of oxygen concentration. Several genes were found to be upregulated by acidosis independent of oxygenation. Acidosis resulted in a more wide-scale change in gene expression profiles than hypoxia including upregulation of genes involved in the translation process, for example Eukaryotic translation initiation factor 4A, isoform 2 (EIF4A2, and Ribosomal protein L37 (RPL37. Acidosis suppressed overall ATP turnover and protein synthesis by 50%. Protein synthesis, but not total ATP production, was also suppressed under hypoxic conditions. A dramatic decrease in ATP turnover (SiHa and protein synthesis (both cell lines was observed when hypoxia and low pHe were combined.We demonstrate here that the influence of hypoxia and acidosis causes different responses, both in gene expression and in de

Long-term delivery of protein therapeutics.

Science.gov (United States)

Vaishya, Ravi; Khurana, Varun; Patel, Sulabh; Mitra, Ashim K

2015-03-01

Proteins are effective biotherapeutics with applications in diverse ailments. Despite being specific and potent, their full clinical potential has not yet been realized. This can be attributed to short half-lives, complex structures, poor in vivo stability, low permeability, frequent parenteral administrations and poor adherence to treatment in chronic diseases. A sustained release system, providing controlled release of proteins, may overcome many of these limitations. This review focuses on recent development in approaches, especially polymer-based formulations, which can provide therapeutic levels of proteins over extended periods. Advances in particulate, gel-based formulations and novel approaches for extended protein delivery are discussed. Emphasis is placed on dosage form, method of preparation, mechanism of release and stability of biotherapeutics. Substantial advancements have been made in the field of extended protein delivery via various polymer-based formulations over last decade despite the unique delivery-related challenges posed by protein biologics. A number of injectable sustained-release formulations have reached market. However, therapeutic application of proteins is still hampered by delivery-related issues. A large number of protein molecules are under clinical trials, and hence, there is an urgent need to develop new methods to deliver these highly potent biologics.

Effect of a long-term high-protein diet on survival, obesity development, and gut microbiota in mice

DEFF Research Database (Denmark)

Kiilerich, Pia; Myrmel, Lene Secher; Fjære, Even

2016-01-01

Female C57BL/6J mice were fed a regular low-fat diet or high-fat diets combined with either high or low protein-to-sucrose ratios during their entire lifespan to examine the long-term effects on obesity development, gut microbiota, and survival. Intake of a high-fat diet with a low protein....../sucrose ratio precipitated obesity and reduced survival relative to mice fed a low-fat diet. By contrast, intake of a high-fat diet with a high protein/sucrose ratio attenuated lifelong weight gain and adipose tissue expansion, and survival was not significantly altered relative to low-fat-fed mice. Our...... findings support the notion that reduced survival in response to high-fat/high-sucrose feeding is linked to obesity development. Digital gene expression analyses, further validated by qPCR, demonstrated that the protein/sucrose ratio modulated global gene expression over time in liver and adipose tissue...

The flavoprotein Tah18-dependent NO synthesis confers high-temperature stress tolerance on yeast cells

Energy Technology Data Exchange (ETDEWEB)

Nishimura, Akira; Kawahara, Nobuhiro [Graduate School of Biological Sciences, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma, Nara 630-0192 (Japan); Takagi, Hiroshi, E-mail: hiro@bs.naist.jp [Graduate School of Biological Sciences, Nara Institute of Science and Technology, 8916-5 Takayama, Ikoma, Nara 630-0192 (Japan)

2013-01-04

Highlights: Black-Right-Pointing-Pointer NO is produced from L-arginine in response to elevated temperature in yeast. Black-Right-Pointing-Pointer Tah18 was first identified as the yeast protein involved in NO synthesis. Black-Right-Pointing-Pointer Tah18-dependent NO synthesis confers tolerance to high-temperature on yeast cells. -- Abstract: Nitric oxide (NO) is a ubiquitous signaling molecule involved in the regulation of a large number of cellular functions. In the unicellular eukaryote yeast, NO may be involved in stress response pathways, but its role is poorly understood due to the lack of mammalian NO synthase (NOS) orthologues. Previously, we have proposed the oxidative stress-induced L-arginine synthesis and its physiological role under stress conditions in yeast Saccharomyces cerevisiae. Here, our experimental results indicated that increased conversion of L-proline into L-arginine led to NO production in response to elevated temperature. We also showed that the flavoprotein Tah18, which was previously reported to transfer electrons to the Fe-S cluster protein Dre2, was involved in NO synthesis in yeast. Gene knockdown analysis demonstrated that Tah18-dependent NO synthesis confers high-temperature stress tolerance on yeast cells. As it appears that such a unique cell protection mechanism is specific to yeasts and fungi, it represents a promising target for antifungal activity.

Effects of harvesting forest biomass on water and climate regulation services: A synthesis of long-term ecosystem experiments in eastern North America

Science.gov (United States)

Caputo, Jesse; Beier, Colin D; Groffman, Peter M; Burns, Douglas A.; Beall, Frederick D; Hazlett, Paul W.; Yorks, Thad E

2016-01-01

Demand for woody biomass fuels is increasing amidst concerns about global energy security and climate change, but there may be negative implications of increased harvesting for forest ecosystem functions and their benefits to society (ecosystem services). Using new methods for assessing ecosystem services based on long-term experimental research, post-harvest changes in ten potential benefits were assessed for ten first-order northern hardwood forest watersheds at three long-term experimental research sites in northeastern North America. As expected, we observed near-term tradeoffs between biomass provision and greenhouse gas regulation, as well as tradeoffs between intensive harvest and the capacity of the forest to remediate nutrient pollution. In both cases, service provision began to recover along with the regeneration of forest vegetation; in the case of pollution remediation, the service recovered to pre-harvest levels within 10 years. By contrast to these two services, biomass harvesting had relatively nominal and transient impacts on other ecosystem services. Our results are sensitive to empirical definitions of societal demand, including methods for scaling societal demand to ecosystem units, which are often poorly resolved. Reducing uncertainty around these parameters can improve confidence in our results and increase their relevance for decision-making. Our synthesis of long-term experimental studies provides insights on the social-ecological resilience of managed forest ecosystems to multiple drivers of change.

Impaired autoregulation of cerebral blood flow in long-term type I (insulin-dependent) diabetic patients with nephropathy and retinopathy

DEFF Research Database (Denmark)

Kastrup, J; Rørsgaard, S; Parving, H H

1986-01-01

Autoregulation of cerebral blood flow, i.e., the maintenance of cerebral blood flow within narrow limits during changes in arterial perfusion pressure, was studied in nine healthy control subjects and in 12 long-term Type I (insulin-dependent) diabetic patients with clinical microangiopathy...... the previous findings suggesting that autoregulation of cerebral blood flow is impaired in some long-term Type I diabetic patients with clinical microangiopathy (arteriolar hyalinosis)........ Cerebral blood flow was measured by the intravenous 133Xenon method. Mean arterial blood pressure was elevated approximately 30 mmHg by intravenous infusion of angiotensin amide II and lowered about 10 mmHg by intravenous infusion of trimethaphan camsylate. In the control subjects the flow/pressure curve...

Hormone-dependent nuclear export of estradiol receptor and DNA synthesis in breast cancer cells

Science.gov (United States)

Lombardi, Maria; Castoria, Gabriella; Migliaccio, Antimo; Barone, Maria Vittoria; Di Stasio, Rosina; Ciociola, Alessandra; Bottero, Daniela; Yamaguchi, Hiroshi; Appella, Ettore; Auricchio, Ferdinando

2008-01-01

In breast cancer cells, cytoplasmic localization of the estradiol receptor α (ERα) regulates estradiol-dependent S phase entry. We identified a nuclear export sequence (NES) in ERα and show that its export is dependent on both estradiol-mediated phosphatidylinositol-3-kinase (PI3K)/AKT activation and chromosome region maintenance 1 (CRM1). A Tat peptide containing the ERα NES disrupts ERα–CRM1 interaction and prevents nuclear export of ERα- and estradiol-induced DNA synthesis. NES-ERα mutants do not exit the nucleus and inhibit estradiol-induced S phase entry; ERα-dependent transcription is normal. ERα is associated with Forkhead proteins in the nucleus, and estradiol stimulates nuclear exit of both proteins. ERα knockdown or ERα NES mutations prevent ERα and Forkhead nuclear export. A mutant of forkhead in rhabdomyosarcoma (FKHR), which cannot be phosphorylated by estradiol-activated AKT, does not associate with ERα and is trapped in the nucleus, blocking S phase entry. In conclusion, estradiol-induced AKT-dependent phosphorylation of FKHR drives its association with ERα, thereby triggering complex export from the nucleus necessary for initiation of DNA synthesis and S phase entry. PMID:18644889

Gamma-ray-induced changes in the synthesis of tomato pericarp protein

International Nuclear Information System (INIS)

Ferullo, J.M.; Nespoulous, L.; Triantaphylides, C.

1994-01-01

The application of massive doses of gamma rays (1–8 kGy) to mature green cherry-tomato fruits led to a transient fall in pericarp tissue protein metabolism within 6h. A separate 3 kGy treatment resulted in the appearance of certain transcripts and proteins, and a reduction in the abundance of others. At the same dose, protein synthesis regained the control level within 24 h, and in addition a new set of proteins was induced. Gamma-induced proteins (referred to as GIPs) were divided into three groups, depending on the time-course of their induction. Group 1 GIPs were synthesized only during the first few hours following treatment, whereas group 2 GIPs were synthesized for at least 48 h. Group 3 GIPs were progressively induced when the control level of synthesis was restored. These results demonstrated that, despite its deleterious effects on DNA and cell structures, irradiation induced an active response in plant tissue. Comparative experiments suggest that the majority of group 1 GIPs might belong to the heat shock protein family. GIPs might play a role in the protection and repair of cellular structures, or may be implicated in physiological disorders triggered by irradiation. (author)

Insulin dependence and pancreatic enzyme replacement therapy are independent prognostic factors for long-term survival after operation for chronic pancreatitis.

Science.gov (United States)

Winny, Markus; Paroglou, Vagia; Bektas, Hüseyin; Kaltenborn, Alexander; Reichert, Benedikt; Zachau, Lea; Kleine, Moritz; Klempnauer, Jürgen; Schrem, Harald

2014-02-01

This retrospective, single-center, observational study on postoperative long-term results aims to define yet unknown factors for long-term outcome after operation for chronic pancreatitis. We analyzed 147 consecutive patients operated for chronic pancreatitis from 2000 to 2011. Mean follow-up was 5.3 years (range, 1 month to 12.7 years). Complete long-term survival data were provided by the German citizen registration authorities for all patients. A quality-of-life questionnaire was sent to surviving patients after a mean follow-up of 5.7 years. Surgical principles were resection (n = 86; 59%), decompression (n = 29; 20%), and hybrid procedures (n = 32; 21%). No significant influences of different surgical principles and operative procedures on survival, long-term quality of life and pain control could be detected. Overall 30-day mortality was 2.7%, 1-year survival 95.9%, and 3-year survival 90.8%. Multivariate Cox regression analysis revealed that only postoperative insulin dependence at the time of hospital discharge (P = .027; Exp(B) = 2.111; 95% confidence interval [CI], 1.089-4.090) and the absence of pancreas enzyme replacement therapy at the time of hospital discharge (P = .039; Exp(B) = 2.102; 95% CI, 1.037-4.262) were significant, independent risk factors for survival with significant hazard ratios for long-term survival. Long-term improvement in quality of life was reported by 55 of 76 long-term survivors (73%). Pancreatic enzyme replacement should be standard treatment after surgery for chronic pancreatitis at the time of hospital discharge, even when no clinical signs of exocrine pancreatic failure exist. This study underlines the potential importance of early operative intervention in chronic pancreatitis before irreversible endocrine dysfunction is present. Copyright © 2014 Mosby, Inc. All rights reserved.

Protective effects of long-term lithium administration in a slowly progressive SMA mouse model.

Science.gov (United States)

Biagioni, Francesca; Ferrucci, Michela; Ryskalin, Larisa; Fulceri, Federica; Lazzeri, Gloria; Calierno, Maria Teresa; Busceti, Carla L; Ruffoli, Riccardo; Fornai, Francesco

2017-12-01

In the present study we evaluated the long-term effects of lithium administration to a knock-out double transgenic mouse model (Smn-/-; SMN1A2G+/-; SMN2+/+) of Spinal Muscle Atrophy type III (SMA-III). This model is characterized by very low levels of the survival motor neuron protein, slow disease progression and motor neuron loss, which enables to detect disease-modifying effects at delayed time intervals. Lithium administration attenuates the decrease in motor activity and provides full protection from motor neuron loss occurring in SMA-III mice, throughout the disease course. In addition, lithium prevents motor neuron enlargement and motor neuron heterotopy and suppresses the occurrence of radial-like glial fibrillary acidic protein immunostaining in the ventral white matter of SMA-III mice. In SMA-III mice long-term lithium administration determines a dramatic increase of survival motor neuron protein levels in the spinal cord. These data demonstrate that long-term lithium administration during a long-lasting motor neuron disorder attenuates behavioural deficit and neuropathology. Since low level of survival motor neuron protein is bound to disease severity in SMA, the robust increase in protein level produced by lithium provides solid evidence which calls for further investigations considering lithium in the long-term treatment of spinal muscle atrophy.

The evolution of the protein synthesis system. I - A model of a primitive protein synthesis system

Science.gov (United States)

Mizutani, H.; Ponnamperuma, C.

1977-01-01

A model is developed to describe the evolution of the protein synthesis system. The model is comprised of two independent autocatalytic systems, one including one gene (A-gene) and two activated amino acid polymerases (O and A-polymerases), and the other including the addition of another gene (N-gene) and a nucleotide polymerase. Simulation results have suggested that even a small enzymic activity and polymerase specificity could lead the system to the most accurate protein synthesis, as far as permitted by transitions to systems with higher accuracy.

Liver protein synthesis stays elevated after chemotherapy in tumour-bearing mice.

Science.gov (United States)

Samuels, Sue E; McLaren, Teresa A; Knowles, Andrew L; Stewart, Sarah A; Madelmont, Jean-Claude; Attaix, Didier

2006-07-28

We studied the effect of chemotherapy on liver protein synthesis in mice bearing colon 26 adenocarcinoma (C26). Liver protein mass decreased (-32%; Psynthesis increased (20-35%; Psynthesis. Increased protein synthesis in tumour-bearing mice was primarily mediated by increasing ( approximately 15%; Psynthesis (Cs; mg RNA/g protein). Cystemustine, a nitrosourea chemotherapy that cures C26 with 100% efficacy, rapidly restored liver protein mass; protein synthesis however stayed higher than in healthy mice ( approximately 15%) throughout the initial and later stages of recovery. Chemotherapy had no significant effect on liver protein mass and synthesis in healthy mice. Reduced food intake was not a factor in this model. These data suggest a high priority for liver protein synthesis during cancer cachexia and recovery.

Long-term continuous N-carbamylglutamate treatment in frequently decompensated propionic acidemia: a case report.

Science.gov (United States)

Tummolo, Albina; Melpignano, Livio; Carella, Antonella; Di Mauro, Anna Maria; Piccinno, Elvira; Vendemiale, Marcella; Ortolani, Federica; Fedele, Stefania; Masciopinto, Maristella; Papadia, Francesco

2018-04-22

Propionic acidemia is a rare autosomal recessive inherited metabolic disorder that can inhibit the synthesis of N-acetylglutamate, the obligatory activator in urea synthesis, leading to hyperammonemia. N-carbamylglutamate ameliorates hyperammonemia in decompensated propionic acidemia. The effects of long-term continuous N-acetylglutamate administration in such patients are unknown. We report our clinical experience with continuous administration of N-acetylglutamate for 6 years in a patient with propionic acidemia frequently presenting with hyperammonemia. A male Caucasian patient with frequently decompensated propionic acidemia and hyperammonemia was admitted 78 times for acute attacks during the first 9 years of his life. Continuous daily treatment with oral N-carbamylglutamate 100 mg/kg (50 mg/kg after 6 months) was initiated. During 6 years of treatment, he had a significant decrease in his mean plasma ammonia levels (75.7 μmol/L vs. 140.3 μmol/L before N-carbamylglutamate therapy, p N-acetylglutamate administration outside the emergency setting. If this observation is confirmed, future studies should aim to optimize the dosage and explore effects of the dosage requirements on other drugs and on protein tolerance.

Age-related changes in the synthesis and phosphorylation of proteins

International Nuclear Information System (INIS)

Butler, J.A.; Heydari, A.; Richardson, A.

1986-01-01

It is well documented that the protein synthetic activity of liver tissue decreases significantly with age. However, very little information is available on the effect of age on the synthesis or phosphorylation of individual proteins. Hepatocytes were isolated from 5- to 30-month-old male Fischer F344 rats, and proteins were labeled with either [ 3 H]-valine or [ 32 P]-phosphate. Two-dimensional polyacrylamide gel electrophoresis was used to monitor the synthesis and phosphorylation of a wide variety of proteins. A dramatic increase or decrease in the synthesis of approximately 2 to 3% of the proteins was observed. Most of the proteins whose synthesis increased with age were found to be plasma proteins, e.g., acute phase proteins, synthesized by the liver. In general, the synthesis of most proteins decreased 20 to 40% with age. The phosphorylation of most proteins (over 200) did not appear to change with age. However the phosphorylation of two acidic proteins (molecular weights of 148 Kd and 130 Kd and pIs of 5.4 and 5.36, respectively) decreased with age while the phosphorylation of a basic protein (molecular weight of 57 Kd and pI of 8.09) increased with age

Post-irradiation replication and repair in UV-irradiated cells of Proteus mirabilis depends on protein synthesis and a functioning rec+ gene

International Nuclear Information System (INIS)

Hofemeister, J.

1977-01-01

The amount of and the molecular weight of newly synthesized DNA (piDNA) as well as its repair after UV irradiation in excision-proficient strains of P.mirabilis and E.coli K12 have been compared. A fraction of post-replication repair (PRR) in P.mirabilis is found to be dependent on de novo protein synthesis after UV irradiation. Pre-irradiation by UV and pre-treatment with nalidixic acid increase the efficiency of post-irradiation replication and PRR even in the presence of chloramphenicol. An inducible repair function in P.mirabilis is supposed to stimulate post-irradiation replication and repair. (author)

Compartmentalized PDE4A5 Signaling Impairs Hippocampal Synaptic Plasticity and Long-Term Memory.

Science.gov (United States)

Havekes, Robbert; Park, Alan J; Tolentino, Rosa E; Bruinenberg, Vibeke M; Tudor, Jennifer C; Lee, Yool; Hansen, Rolf T; Guercio, Leonardo A; Linton, Edward; Neves-Zaph, Susana R; Meerlo, Peter; Baillie, George S; Houslay, Miles D; Abel, Ted

2016-08-24

Alterations in cAMP signaling are thought to contribute to neurocognitive and neuropsychiatric disorders. Members of the cAMP-specific phosphodiesterase 4 (PDE4) family, which contains >25 different isoforms, play a key role in determining spatial cAMP degradation so as to orchestrate compartmentalized cAMP signaling in cells. Each isoform binds to a different set of protein complexes through its unique N-terminal domain, thereby leading to targeted degradation of cAMP in specific intracellular compartments. However, the functional role of specific compartmentalized PDE4 isoforms has not been examined in vivo Here, we show that increasing protein levels of the PDE4A5 isoform in mouse hippocampal excitatory neurons impairs a long-lasting form of hippocampal synaptic plasticity and attenuates hippocampus-dependent long-term memories without affecting anxiety. In contrast, viral expression of a truncated version of PDE4A5, which lacks the unique N-terminal targeting domain, does not affect long-term memory. Further, overexpression of the PDE4A1 isoform, which targets a different subset of signalosomes, leaves memory undisturbed. Fluorescence resonance energy transfer sensor-based cAMP measurements reveal that the full-length PDE4A5, in contrast to the truncated form, hampers forskolin-mediated increases in neuronal cAMP levels. Our study indicates that the unique N-terminal localization domain of PDE4A5 is essential for the targeting of specific cAMP-dependent signaling underlying synaptic plasticity and memory. The development of compounds to disrupt the compartmentalization of individual PDE4 isoforms by targeting their unique N-terminal domains may provide a fruitful approach to prevent cognitive deficits in neuropsychiatric and neurocognitive disorders that are associated with alterations in cAMP signaling. Neurons exhibit localized signaling processes that enable biochemical cascades to be activated selectively in specific subcellular compartments. The

The MreB-like protein Mbl of Streptomyces coelicolor A3(2) depends on MreB for proper localization and contributes to spore wall synthesis.

Science.gov (United States)

Heichlinger, Andrea; Ammelburg, Moritz; Kleinschnitz, Eva-Maria; Latus, Annette; Maldener, Iris; Flärdh, Klas; Wohlleben, Wolfgang; Muth, Günther

2011-04-01

Most bacteria with a rod-shaped morphology contain an actin-like cytoskeleton consisting of MreB polymers, which form helical spirals underneath the cytoplasmic membrane to direct peptidoglycan synthesis for the elongation of the cell wall. In contrast, MreB of Streptomyces coelicolor is not required for vegetative growth but has a role in sporulation. Besides MreB, S. coelicolor encodes two further MreB-like proteins, Mbl and SCO6166, whose function is unknown. Whereas MreB and Mbl are highly similar, SCO6166 is shorter, lacking the subdomains IB and IIB of actin-like proteins. Here, we showed that MreB and Mbl are not functionally redundant but cooperate in spore wall synthesis. Expression analysis by semiquantitative reverse transcription-PCR revealed distinct expression patterns. mreB and mbl are induced predominantly during morphological differentiation. In contrast, sco6166 is strongly expressed during vegetative growth but switched off during sporulation. All genes could be deleted without affecting viability. Even a ΔmreB Δmbl double mutant was viable. Δsco6166 had a wild-type phenotype. ΔmreB, Δmbl, and ΔmreB Δmbl produced swollen, prematurely germinating spores that were sensitive to various kinds of stress, suggesting a defect in spore wall integrity. During aerial mycelium formation, an Mbl-mCherry fusion protein colocalized with an MreB-enhanced green fluorescent protein (MreB-eGFP) fusion protein at the sporulation septa. Whereas MreB-eGFP localized properly in the Δmbl mutant, Mbl-mCherry localization depended on the presence of a functional MreB protein. Our results revealed that MreB and Mbl cooperate in the synthesis of the thickened spore wall, while SCO6166 has a nonessential function during vegetative growth.

Retinal protein synthesis in relationship to environmental lighting

International Nuclear Information System (INIS)

Hollyfield, J.G.; Anderson, R.E.

1982-01-01

A series of in vivo and in vitro experiments using Xenopus laevis juvenile toads was conducted to probe the relationship between environmental lighting and protein synthesis in the retina. Autoradiographic and biochemical analyses indicated that measurable changes in protein synthesis did not occur during a normal diurnal cycle when animals were conditioned to 12 hr light followed by 12 hr darkness each day (LD). However, when retinas from animals maintained in continuous darkness (DD) for 3 days were incubated with 3 H-leucine, there was a 40% reduction in the specific radioactivity of total retinal proteins compared with retinas from animals maintained in continuous light (LL) for 3 days or on the LD cycle. Retinas from DD animals injected with 3 H-leucine showed a 48% reduction in protein synthesis compared with retinas of LL animals. In autoradiographs of retinas from in vivo or in vitro experiments, grain counts were 40% lower in the total retinas of the DD animals compared with retinas of LL animals. This reduction occurred throughout the entire retina and was not restricted to any specific cell type. There was also a 35% reduction in the rate of radioactive band displacement in the rod outer segments of DD animals, although the percent of 3 H-leucine incorporated into opsin relative to total retinal protein was the same for both groups. We conclude from these studies that fluctuations in the rate of protein synthesis during the normal light-dark cycle are not detectable. However, major differences in protein synthesis are evident when animals are stressed with continuous darkness for several days. This effect is not restricted to any particular retinal layer but occurs throughout the entire retina. Moreover, prolonged darkness affects protein synthesis in extraocular tissues as well

Synthesis of protein in host-free reticulate bodies of Chlamydia psittaci and Chlamydia trachomatis

International Nuclear Information System (INIS)

Hatch, T.P.; Miceli, M.; Silverman, J.A.

1985-01-01

Synthesis of protein by the obligate intracellular parasitic bacteria Chlamydia psittaci (6BC) and Chlamydia trachomatis (serovar L2) isolated from host cells (host-free chlamydiae) was demonstrated for the first time. Incorporation of [ 35 S]methionine and [ 35 S]cysteine into trichloroacetic acid-precipitable material by reticulate bodies of chlamydiae persisted for 2 h and was dependent upon a exogenous source of ATP, an ATP-regenerating system, and potassium or sodium ions. Magnesium ions and amino acids stimulated synthesis; chloramphenicol, rifampin, oligomycin, and carbonyl cyanide p-trifluoromethoxyphenylhydrazone (a proton ionophore) inhibited incorporation. Ribonucleoside triphosphates (other than ATP) had little stimulatory effect. The optimum pH for host-free synthesis was between 7.0 and 7.5. The molecular weights of proteins synthesized by host-free reticulate bodies closely resembled the molecular weights of proteins synthesized by reticulate bodies in an intracellular environment, and included outer membrane proteins. Elementary bodies of chlamydiae were unable to synthesize protein even when incubated in the presence of 10 mM dithiothreitol, a reducing agent which converted the highly disulfide bond cross-linked major outer membrane protein to monomeric form

Modulation of protein synthesis and secretion by substratum in primary cultures of rat hepatocytes

International Nuclear Information System (INIS)

Sudhakaran, P.R.; Stamatoglou, S.C.; Hughes, R.C.

1986-01-01

Hepatocytes isolated by perfusion of adult rat liver and cultured on substrata consisting of one or more of the major components of the liver biomatrix (fibronectin, laminin, type IV collagen) have been examined for the synthesis of defined proteins. Under these conditions, tyrosine amino transferase, a marker of hepatocyte function, is maintained at similar levels in response to dexamethasone over 5 days in culture on each substratum, and total cellular protein synthesis remains constant. By contrast, there is a rapid decrease in synthesis and secretion of albumin and a 3-7-fold increase in synthesis and section of α-fetoprotein which are most marked on a laminin substratum, but least evident on type IV collagen, and an increased synthesis of fibronectin and type IV collagen. The newly synthesized matrix proteins are present in the cell layer as well as in cell secretions. The enhanced synthesis of fibronectin is less in cells seeded onto a fibronectin substratum than on laminin or type IV collagen substrata. These results indicate that hepatocytes cultured in serum-free medium on substrata composed of components of the liver biomatrix maintain certain functions of the differentiated state (tyrosine amino transferase), lose others (albumin secretion) and switch to increased synthesis of matrix components as well as fetal markers such as α-fetoprotein. The magnitude of these effects depends on the substratum on which the hepatocytes are cultured

A low-protein diet restricts albumin synthesis in nephrotic rats.

OpenAIRE

Kaysen, G A; Jones, H; Martin, V; Hutchison, F N

1989-01-01

High-protein diets increase albumin synthesis in rats with Heymann nephritis but albuminuria increases also, causing serum albumin concentration to be suppressed further than in nephrotic animals eating a low-protein diet. Experiments were designed to determine whether dietary protein augmentation directly stimulates albumin synthesis, or whether instead increased albumin synthesis is triggered by the decrease in serum albumin concentration. Evidence is presented that dietary protein augmenta...

Inhibition of chloroplast protein synthesis following light chilling of tomato

International Nuclear Information System (INIS)

Kent, J.; Ort, D.

1989-01-01

In the present study we looked at the effects of a high light chill on the pulsed incorporation of 35 S methionine into total, stromal, and thylakoid proteins of lightly abraded leaflets of 18-21 day old tomato (Lycopersicon esculentum Mill ca. Floramerica) seedlings. Based on gel fluorographic patterns of marker proteins that are indicative of the net rates of chloroplast and cytoplasmic protein synthesis, there appears to be a nearly complete cessation of chloroplastic protein synthesis. No labeling is observed for either the stromal large subunit of Rubisco or the thylakoid-bound alpha and beta subunits of the coupling factor. One notable exception, however, appears to be the 32 kd, D1 protein. Its net synthetic rate remains high despite the inhibition of other chloroplastically synthesized proteins. The small subunit of Rubicso, LHCP-II, as well as several other proteins of known cytoplasmic origin, were still synthesized, albeit, at lower than control rates. Light chilling of chill-insensitive spinach produced a similar, but less dramatic differential behavior between chloroplastic and cytoplasmic protein synthesis. It appears, in chilling-sensitive plants, that chloroplast protein synthesis exhibits a greater sensitivity to low temperature inhibition than does cytoplasmic protein synthesis and that recovery of chloroplast protein synthesis may play an important role in recovery of photosynthetic activity following chilling

The role of mTOR signaling in the regulation of protein synthesis and muscle mass during immobilization in mice

Science.gov (United States)

You, Jae-Sung; Anderson, Garrett B.; Dooley, Matthew S.; Hornberger, Troy A.

2015-01-01

ABSTRACT The maintenance of skeletal muscle mass contributes substantially to health and to issues associated with the quality of life. It has been well recognized that skeletal muscle mass is regulated by mechanically induced changes in protein synthesis, and that signaling by mTOR is necessary for an increase in protein synthesis and the hypertrophy that occurs in response to increased mechanical loading. However, the role of mTOR signaling in the regulation of protein synthesis and muscle mass during decreased mechanical loading remains largely undefined. In order to define the role of mTOR signaling, we employed a mouse model of hindlimb immobilization along with pharmacological, mechanical and genetic means to modulate mTOR signaling. The results first showed that immobilization induced a decrease in the global rates of protein synthesis and muscle mass. Interestingly, immobilization also induced an increase in mTOR signaling, eIF4F complex formation and cap-dependent translation. Blocking mTOR signaling during immobilization with rapamycin not only impaired the increase in eIF4F complex formation, but also augmented the decreases in global protein synthesis and muscle mass. On the other hand, stimulating immobilized muscles with isometric contractions enhanced mTOR signaling and rescued the immobilization-induced decrease in global protein synthesis through a rapamycin-sensitive mechanism that was independent of ribosome biogenesis. Unexpectedly, the effects of isometric contractions were also independent of eIF4F complex formation. Similar to isometric contractions, overexpression of Rheb in immobilized muscles enhanced mTOR signaling, cap-dependent translation and global protein synthesis, and prevented the reduction in fiber size. Therefore, we conclude that the activation of mTOR signaling is both necessary and sufficient to alleviate the decreases in protein synthesis and muscle mass that occur during immobilization. Furthermore, these results indicate

The antituberculosis antibiotic capreomycin inhibits protein synthesis by disrupting interaction between ribosomal proteins L12 and L10.

Science.gov (United States)

Lin, Yuan; Li, Yan; Zhu, Ningyu; Han, Yanxing; Jiang, Wei; Wang, Yanchang; Si, Shuyi; Jiang, Jiandong

2014-01-01

Capreomycin is a second-line drug for multiple-drug-resistant tuberculosis (TB). However, with increased use in clinics, the therapeutic efficiency of capreomycin is decreasing. To better understand TB resistance to capreomycin, we have done research to identify the molecular target of capreomycin. Mycobacterium tuberculosis ribosomal proteins L12 and L10 interact with each other and constitute the stalk of the 50S ribosomal subunit, which recruits initiation and elongation factors during translation. Hence, the L12-L10 interaction is considered to be essential for ribosomal function and protein synthesis. Here we provide evidence showing that capreomycin inhibits the L12-L10 interaction by using an established L12-L10 interaction assay. Overexpression of L12 and/or L10 in M. smegmatis, a species close to M. tuberculosis, increases the MIC of capreomycin. Moreover, both elongation factor G-dependent GTPase activity and ribosome-mediated protein synthesis are inhibited by capreomycin. When protein synthesis was blocked with thiostrepton, however, the bactericidal activity of capreomycin was restrained. All of these results suggest that capreomycin seems to inhibit TB by interrupting the L12-L10 interaction. This finding might provide novel clues for anti-TB drug discovery.

Roles of Fragile X Mental Retardation Protein in Dopaminergic Stimulation-induced Synapse-associated Protein Synthesis and Subsequent α-Amino-3-hydroxyl-5-methyl-4-isoxazole-4-propionate (AMPA) Receptor Internalization*

OpenAIRE

Wang, Hansen; Kim, Susan S.; Zhuo, Min

2010-01-01

Fragile X syndrome, the most common form of inherited mental retardation, is caused by the absence of the RNA-binding protein fragile X mental retardation protein (FMRP). FMRP regulates local protein synthesis in dendritic spines. Dopamine (DA) is involved in the modulation of synaptic plasticity. Activation of DA receptors can regulate higher brain functions in a protein synthesis-dependent manner. Our recent study has shown that FMRP acts as a key messenger for DA modulation in forebrain ne...

Protein synthesis in the presence of carbamoyl-amino acids

International Nuclear Information System (INIS)

Kraus, L.M.; Stephens, M.C.

1987-01-01

The role of exogenous carbamoyl-amino acids in protein biosynthesis has been examined in vitro using a mixture of 14 C amino acids to label newly synthesized protein in human reticulocyte rich (8-18%) peripheral blood. Aliquots of the radiolabeled newly synthesized protein were acid precipitated, washed and the radioactivity measured. Control samples which measured the synthetic capacity of the blood were aliquots of the same blood- 14 C amino acid mixture without added carbamoyl-amino acids or cyanate. N-carbamoyl leucine alone or a 3 N-carbamoyl amino acid mixture of leucine, aspartic acid and tyrosine were used to test inhibition of protein synthesis. Also carbamoyl-amino acids were synthesized using cyanate and Pierce hydrolyzate amino acid calibration standards or the mixture of 14 C amino acids. In this system the carbamoylation of endogenous amino acids by cyanate up to 8 μmol/100μl showed a linear decrease in protein synthesis with time which is inversely related to the cyanate concentration. At greater cyanate levels the inhibition of protein synthesis reaches a plateau. When N-carbamoyl-amino acids only are present there is about a 50% decrease in the 14 C protein at 30 minutes as compared to the synthesis of 14 C protein without N-carbamoyl-amino acids. These results indicate that the presence of carbamoyl-amino acids interferes with protein synthesis

CLIMATE CHANGE: LONG-TERM TRENDS AND SHORT-TERM OSCILLATIONS

Institute of Scientific and Technical Information of China (English)

GAO Xin-quan; ZHANG Xin; QIAN Wei-hong

2006-01-01

Identifying the Northern Hemisphere (NH) temperature reconstruction and instrumental data for the past 1000 years shows that climate change in the last millennium includes long-term trends and various oscillations. Two long-term trends and the quasi-70-year oscillation were detected in the global temperature series for the last 140 years and the NH millennium series. One important feature was emphasized that temperature decreases slowly but it increases rapidly based on the analysis of different series. Benefits can be obtained of climate change from understanding various long-term trends and oscillations. Millennial temperature proxies from the natural climate system and time series of nonlinear model system are used in understanding the natural climate change and recognizing potential benefits by using the method of wavelet transform analysis. The results from numerical modeling show that major oscillations contained in numerical solutions on the interdecadal timescale are consistent with that of natural proxies. It seems that these oscillations in the climate change are not directly linked with the solar radiation as an external forcing. This investigation may conclude that the climate variability at the interdecadal timescale strongly depends on the internal nonlinear effects in the climate system.

The roles of the cyclo-oxygenases types one and two in prostaglandin synthesis in human fetal membranes at term.

Science.gov (United States)

Sawdy, R J; Slater, D M; Dennes, W J; Sullivan, M H; Bennett, P R

2000-01-01

The aim of this study was to determine the relative contributions of cyclo-oxygenase (COX) types 1 and 2 to prostaglandin synthesis at term. Fetal membranes were collected from 6 pregnancies after elective caesarean section at term, prior to labour. The presence of COX-1 and COX-2 protein was determined using Western analysis. The relative contributions of the two isoforms of COX to prostaglandin synthesis were determined by incubation of fetal membrane discs with either a COX-2 selective inhibitor, SC236, or a COX-1 selective inhibitor, SC560, and measurement of prostaglandin release during 24 h using enzyme-linked immuno-sorbent assay (ELISA). Both COX-1 and COX-2 protein were demonstrated in amnion and chorion-decidua. The COX-2 selective inhibitor, SC-236, significantly reduced prostaglandin synthesis, both in its COX-2 specific and higher, non-specific concentration ranges. The COX-1 selective inhibitor, SC-560, had no effect upon prostaglandin synthesis in its COX-1 specific concentration range, but did significantly reduce prostaglandin synthesis at higher, non-selective concentrations. Fetal membranes contain both COX-1 and COX-2 at term, but only COX-2 contributes towards prostaglandin synthesis. COX-2 selective NSAI drugs will be as effective as non-selective agents in inhibition of fetal membrane prostaglandin synthesis and may represent a new strategy for tocolysis. Copyright 2000 Harcourt Publishers Ltd.

Transpeptidase activity of penicillin-binding protein SpoVD in peptidoglycan synthesis conditionally depends on the disulfide reductase StoA.

Science.gov (United States)

Bukowska-Faniband, Ewa; Hederstedt, Lars

2017-07-01

Endospore cortex peptidoglycan synthesis is not required for bacterial growth but essential for endospore heat resistance. It therefore constitutes an amenable system for research on peptidoglycan biogenesis. The Bacillus subtilis sporulation-specific class B penicillin-binding protein (PBP) SpoVD and many homologous PBPs contain two conserved cysteine residues of unknown function in the transpeptidase domain - one as residue x in the SxN catalytic site motif and the other in a flexible loop near the catalytic site. A disulfide bond between these residues blocks the function of SpoVD in cortex synthesis. With a combination of experiments with purified proteins and B. subtilis mutant cells, it was shown that in active SpoVD the two cysteine residues most probably interact by hydrogen bonding and that this is important for peptidoglycan synthesis in vivo. It was furthermore demonstrated that the sporulation-specific thiol-disulfide oxidoreductase StoA reduces SpoVD and that requirement of StoA for cortex synthesis can be suppressed by two completely different types of structural alterations in SpoVD. It is concluded that StoA plays a critical role mainly during maturation of SpoVD in the forespore outer membrane. The findings advance our understanding of essential PBPs and redox control of extra-cytoplasmic protein disulfides in bacterial cells. © 2017 The Authors. Molecular Microbiology Published by John Wiley & Sons Ltd.

Aberrant regulation of synthesis and degradation of viral proteins in coliphage lambda-infected UV-irradiated cells and in minicells

International Nuclear Information System (INIS)

Shaw, J.E.; Epp, C.; Pearson, M.L.; Reeve, J.N.

1987-01-01

The patterns of bacteriophage lambda proteins synthesized in UV-irradiated Escherichia coli cells and in anucleate minicells are significantly different; both systems exhibit aberrations of regulation in lambda gene expression. In unirradiated cells or cells irradiated with low UV doses (less than 600 J/m2), regulation of lambda protein synthesis is controlled by the regulatory proteins CI, N, CII, CIII, Cro, and Q. As the UV dose increases, activation of transcription of the cI, rexA, and int genes by CII and CIII proteins fails to occur and early protein synthesis, normally inhibited by the action of Cro, continues. After high UV doses (greater than 2000 J/m2), late lambda protein synthesis does not occur. Progression through the sequence of regulatory steps in lambda gene expression is slower in infected minicells. In minicells, there is no detectable cII- and cIII-dependent synthesis of CI, RexA, or Int proteins and inhibition of early protein synthesis by Cro activity is always incomplete. The synthesis of early b region proteins is not subject to control by CI, N, or Cro proteins, and evidence is presented suggesting that, in minicells, transcription of the early b region is initiated at a promoter(s) within the b region. Proteolytic cleavage of the regulatory proteins O and N and of the capsid proteins C, B, and Nu3 is much reduced in infected minicells. Exposure of minicells to very high UV doses before infection does not completely inhibit late lambda protein synthesis

Intestinal mucosa in diabetes: synthesis of total proteins and sucrase-isomaltase

International Nuclear Information System (INIS)

Olsen, W.A.; Perchellet, E.; Malinowski, R.L.

1986-01-01

The effects of insulin deficiency on nitrogen metabolism in muscle and liver have been extensively studied with recent in vivo demonstration of impaired protein synthesis in rats with streptozotocin-induced diabetes. Despite the significant contribution of small intestinal mucosa to overall protein metabolism, the effect of insulin deficiency on intestinal protein synthesis have not been completely defined. The authors studied the effects of streptozotocin-induced diabetes on total protein synthesis by small intestinal mucosa and on synthesis of a single enzyme protein of the enterocyte brush-border membrane sucrase-isomaltase. They used the flood-dose technique to minimize the difficulties of measuring specific radioactivity of precursor phenylalanine and determined incorporation into mucosal proteins and sucrase-isomaltase 20 min after injection of the labeled amino acid. Diabetes did not alter mucosal mass as determined by weight and content of protein and DNA during the 5 days after injection of streptozotocin. Increased rates of sucrase-isomaltase synthesis developed beginning on day 3, and those of total protein developed on day 5. Thus intestinal mucosal protein synthesis is not an insulin-sensitive process

Phosphodiesterase 10A inhibition attenuates sleep deprivation-induced deficits in long-term fear memory.

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Guo, Lengqiu; Guo, Zhuangli; Luo, Xiaoqing; Liang, Rui; Yang, Shui; Ren, Haigang; Wang, Guanghui; Zhen, Xuechu

2016-12-02

Sleep, particularly rapid eye movement (REM) sleep, is implicated in the consolidation of emotional memories. In the present study, we investigated the protective effects of a phosphodiesterase 10A (PDE10A) inhibitor MP-10 on deficits in long-term fear memory induced by REM sleep deprivation (REM-SD). REM-SD caused deficits in long-term fear memory, however, MP-10 administration ameliorated the deleterious effects of REM-SD on long term fear memory. Brain-derived neurotropic factor (BDNF) and phosphorylated cAMP response element-binding protein (pCREB) were altered in specific brain regions associated with learning and memory in REM-SD rats. Accordingly, REM-SD caused a significant decrease of pCREB in hippocampus and striatum and a significant decrease of BDNF in the hippocampus, striatum and amygdala, however, MP-10 reversed the effects of REM-SD in a dose-dependent manner. Our findings suggest that REM-SD disrupts the consolidation of long-term fear memory and that administration of MP-10 protects the REM-SD-induced deficits in fear memory, which may be due to the MP-10-induced expression of BDNF in the hippocampus, striatum and amygdala, and phosphorylation of CREB in the hippocampus and striatum. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

Regulation of protein synthesis during sea urchin early development

International Nuclear Information System (INIS)

Kelso, L.C.

1989-01-01

Fertilization of the sea urchin egg results in a 20-40 fold increase in the rate of protein synthesis. The masked message hypothesis proposes that mRNAs are masked or unavailable for translation in the egg. We devised an in vivo assay to test this hypothesis. Our results show that masked mRNAs limit protein synthesis in the unfertilized egg. In addition, we show that protein synthesis is also regulated at the level of translational machinery. Following fertilization is a period of rapid cell divisions. This period, known as the rapid cleavage stage, is characterized by the transient synthesis of a novel set of proteins. The synthesis of these proteins is programmed by maternal mRNAs stored in the unfertilized egg. To study the behavior of these mRNAs, we prepared a cDNA library from polysomal poly (A+) RNA from 2-hour embryos. [ 32 P] labeled probes, prepared from the cDNA library, were used to monitor the levels of individual mRNAs in polysomes at fertilization and during early development

Measurement of protein synthesis: in vitro comparison of (68)Ga-DOTA-puromycin, [ (3)H]tyrosine, and 2-fluoro-[ (3)H]tyrosine.

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Eigner, Sebastian; Beckford Vera, Denis R; Fellner, Marco; Loktionova, Natalia S; Piel, Markus; Melichar, Frantisek; Rösch, Frank; Roß, Tobias L; Lebeda, Ondrej; Henke, Katerina Eigner

2013-01-01

Puromycin has played an important role in our understanding of the eukaryotic ribosome and protein synthesis. It has been known for more than 40 years that this antibiotic is a universal protein synthesis inhibitor that acts as a structural analog of an aminoacyl-transfer RNA (aa-tRNA) in eukaryotic ribosomes. Due to the role of enzymes and their synthesis in situations of need (DNA damage, e.g., after chemo- or radiation therapy), determination of protein synthesis is important for control of antitumor therapy, to enhance long-term survival of tumor patients, and to minimize side-effects of therapy. Multiple attempts to reach this goal have been made through the last decades, mostly using radiolabeled amino acids, with limited or unsatisfactory success. The aim of this study is to estimate the possibility of determining protein synthesis ratios by using (68)Ga-DOTA-puromycin ((68)Ga-DOTA-Pur), [(3)H]tyrosine, and 2-fluoro-[(3)H]tyrosine and to estimate the possibility of different pathways due to the fluorination of tyrosine. DOTA-puromycin was synthesized using a puromycin-tethered controlled-pore glass (CPG) support by the usual protocol for automated DNA and RNA synthesis following our design. (68)Ga was obtained from a (68)Ge/(68)Ga generator as described previously by Zhernosekov et al. (J Nucl Med 48:1741-1748, 2007). The purified eluate was used for labeling of DOTA-puromycin at 95°C for 20 min. [(3)H]Tyrosine and 2-fluoro-[(3)H]tyrosine of the highest purity available were purchased from Moravek (Bera, USA) or Amersham Biosciences (Hammersmith, UK). In vitro uptake and protein incorporation as well as in vitro inhibition experiments using cycloheximide to inhibit protein synthesis were carried out for all three substances in DU145 prostate carcinoma cells (ATCC, USA). (68)Ga-DOTA-Pur was additionally used for μPET imaging of Walker carcinomas and AT1 tumors in rats. Dynamic scans were performed for 45 min after IV application (tail vein) of 20-25 MBq (68

Opening remarks for a panel discussion on short-term vs long-term procurement

International Nuclear Information System (INIS)

Courtenay, R.H.

1990-01-01

Long-term contracting in the late 1970's and early 1980's is blamed for some of the inequities that plague the uranium industry today. Utilities are obliged to pay prices far above prevailing levels and relatively low cost producers are forced to shut down while watching less efficient suppliers stay in business thanks to their long term supply agreements. Furthermore, it is argued that long-term contracts have contributed to supply instability by forcing the buildup of surplus inventories and by supporting excess incremental production by suppliers who have a baseload of long-term contracts. The depressed prices resulting from this oversupply are in turn jeopardizing future resource development and damaging supply reliability. In summary, the author's argument is that supply reliability will be greatly enhanced by the assurance of adequate primary supply from traditional sources such as Canada. This will not happen without long-term contracts. This conclusion may not be expected coming from a representative of Canada's largest uranium producer. But the final comment is less self serving. Many of the critics of long term contracts apparently expect a continuing and plentiful supply of East Bloc uranium to the spot market. A further question is to what extent East Bloc suppliers will eventually require long-term contracts in order to maintain production facilitates in economies that are no longer centrally planned, and where there is open competition for capital. Ultimately, reliability of supply from the non-traditional suppliers may also depend on long-term contracts

Adeno-associated virus rep protein synthesis during productive infection

International Nuclear Information System (INIS)

Redemann, B.E.; Mendelson, E.; Carter, B.J.

1989-01-01

Adeno-associated virus (AAV) Rep proteins mediate viral DNA replication and can regulate expression from AAV genes. The authors studied the kinetics of synthesis of the four Rep proteins, Rep78, Rep68, Rep52, and Rep40, during infection of human 293 or KB cells with AAV and helper adenovirus by in vivo labeling with [ 35 S]methionine, immunoprecipitation, and immunoblotting analyses. Rep78 and Rep52 were readily detected concomitantly with detection of viral monomer duplex DNA replicating about 10 to 12 h after infection, and Rep68 and Rep40 were detected 2 h later. Rep78 and Rep52 were more abundant than Rep68 and Rep40 owing to a higher synthesis rate throughout the infectious cycle. In some experiments, very low levels of Rep78 could be detected as early as 4 h after infection. The synthesis rates of Rep proteins were maximal between 14 and 24 h and then decreased later after infection. Isotopic pulse-chase experiments showed that each of the Rep proteins was synthesized independently and was stable for at least 15 h. A slower-migrating, modified form of Rep78 was identified late after infection. AAV capsid protein synthesis was detected at 10 to 12 h after infection and also exhibited synthesis kinetics similar to those of the Rep proteins. AAV DNA replication showed at least two clearly defined stages. Bulk duplex replicating DNA accumulation began around 10 to 12 h and reached a maximum level at about 20 h when Rep and capsid protein synthesis was maximal. Progeny single-stranded DNA accumulation began about 12 to 13 h, but most of this DNA accumulated after 24 h when Rep and capsid protein synthesis had decreased

Dendritic protein synthesis in the normal and diseased brain

Science.gov (United States)

Swanger, Sharon A.; Bassell, Gary J.

2015-01-01

Synaptic activity is a spatially-limited process that requires a precise, yet dynamic, complement of proteins within the synaptic micro-domain. The maintenance and regulation of these synaptic proteins is regulated, in part, by local mRNA translation in dendrites. Protein synthesis within the postsynaptic compartment allows neurons tight spatial and temporal control of synaptic protein expression, which is critical for proper functioning of synapses and neural circuits. In this review, we discuss the identity of proteins synthesized within dendrites, the receptor-mediated mechanisms regulating their synthesis, and the possible roles for these locally synthesized proteins. We also explore how our current understanding of dendritic protein synthesis in the hippocampus can be applied to new brain regions and to understanding the pathological mechanisms underlying varied neurological diseases. PMID:23262237

Predicting long-term temperature increase for time-dependent SAR levels with a single short-term temperature response.

Science.gov (United States)

Carluccio, Giuseppe; Bruno, Mary; Collins, Christopher M

2016-05-01

Present a novel method for rapid prediction of temperature in vivo for a series of pulse sequences with differing levels and distributions of specific energy absorption rate (SAR). After the temperature response to a brief period of heating is characterized, a rapid estimate of temperature during a series of periods at different heating levels is made using a linear heat equation and impulse-response (IR) concepts. Here the initial characterization and long-term prediction for a complete spine exam are made with the Pennes' bioheat equation where, at first, core body temperature is allowed to increase and local perfusion is not. Then corrections through time allowing variation in local perfusion are introduced. The fast IR-based method predicted maximum temperature increase within 1% of that with a full finite difference simulation, but required less than 3.5% of the computation time. Even higher accelerations are possible depending on the time step size chosen, with loss in temporal resolution. Correction for temperature-dependent perfusion requires negligible additional time and can be adjusted to be more or less conservative than the corresponding finite difference simulation. With appropriate methods, it is possible to rapidly predict temperature increase throughout the body for actual MR examinations. © 2015 Wiley Periodicals, Inc.

Post-Training Intrahippocampal Inhibition of Class I Histone Deacetylases Enhances Long-Term Object-Location Memory

Science.gov (United States)

Hawk, Joshua D.; Florian, Cedrick; Abel, Ted

2011-01-01

Long-term memory formation involves covalent modification of the histone proteins that package DNA. Reducing histone acetylation by mutating histone acetyltransferases impairs long-term memory, and enhancing histone acetylation by inhibiting histone deacetylases (HDACs) improves long-term memory. Previous studies using HDAC inhibitors to enhance…

Chlorophyll biosynthesis and assembly into chlorophyll-protein complexes in isolated developing chloroplasts

International Nuclear Information System (INIS)

Bhaya, D.; Castelfranco, P.A.

1985-01-01

Isolated developing plastids from greening cucumber cotyledons or from photoperiodically grown pea seedlings incorporated 14 C-labeled 5-aminolevulinic acid (ALA) into chlorophyll (Chl). Incorporation was light dependent, enhanced by S-adenosylmethionine, and linear for 1 hr. The in vitro rate of Chl synthesis from ALA was comparable to the in vivo rate of Chl accumulation. Levulinic acid and dioxoheptanoic acid strongly inhibited Chl synthesis but not plastid protein synthesis. Neither chloramphenicol nor spectinomycin affected Chl synthesis, although protein synthesis was strongly inhibited. Components of thylakoid membranes from plastids incubated with [ 14 C]ALA were resolved by electrophoresis and then subjected to autoradiography. This work showed that (i) newly synthesized Chl was assembled into Chl-protein complexes and (ii) the inhibition of protein synthesis during the incubation did not alter the labeling pattern. Thus, there was no observable short-term coregulation between Chl synthesis (from ALA) and the synthesis of membrane proteins in isolated plastids

Long-term manure amendments reduced soil aggregate stability via redistribution of the glomalin-related soil protein in macroaggregates

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Xie, Hongtu; Li, Jianwei; Zhang, Bin; Wang, Lianfeng; Wang, Jingkuan; He, Hongbo; Zhang, Xudong

2015-01-01

Glomalin-related soil protein (GRSP) contributes to the formation and maintenance of soil aggregates, it is however remains unclear whether long-term intensive manure amendments alter soil aggregates stability and whether GRSP regulates these changes. Based on a three-decade long fertilization experiment in northeast China, this study examined the impact of long-term manure input on soil organic carbon (SOC), total and easily extractable GRSP (GRSPt and GRSPe) and their respective allocations in four soil aggregates (>2000 μm; 2000–250 μm; 250–53 μm; and soil and SOC in each aggregate generally increased with increasing manure input, GRSPt and GRSPe in each aggregate showed varying changes with manure input. Both GRSP in macroaggregates (2000–250 μm) were significantly higher under low manure input, a pattern consistent with changes in soil aggregate stability. Constituting 38~49% of soil mass, macroaggregates likely contributed to the nonlinear changes of aggregate stability under manure amendments. The regulatory process of GRSP allocations in soil aggregates has important implications for manure management under intensive agriculture. PMID:26423355

STAT6-Dependent Collagen Synthesis in Human Fibroblasts Is Induced by Bovine Milk.

Directory of Open Access Journals (Sweden)

Stefan Kippenberger

Full Text Available Since the domestication of the urus, 10.000 years ago, mankind utilizes bovine milk for different purposes. Besides usage as a nutrient also the external application of milk on skin has a long tradition going back to at least the ancient Aegypt with Cleopatra VII as a great exponent. In order to test whether milk has impact on skin physiology, cultures of human skin fibroblasts were exposed to commercial bovine milk. Our data show significant induction of proliferation by milk (max. 2,3-fold, EC50: 2,5% milk without toxic effects. Surprisingly, bovine milk was identified as strong inducer of collagen 1A1 synthesis at both, the protein (4-fold, EC50: 0,09% milk and promoter level. Regarding the underlying molecular pathways, we show functional activation of STAT6 in a p44/42 and p38-dependent manner. More upstream, we identified IGF-1 and insulin as key factors responsible for milk-induced collagen synthesis. These findings show that bovine milk contains bioactive molecules that act on human skin cells. Therefore, it is tempting to test the herein introduced concept in treatment of atrophic skin conditions induced e.g. by UV light or corticosteroids.

Post-irradiation replication and repair in uv-irradiated cells of Proteus mirabilis depends on protein synthesis and a functioning rec/sup +/ gene

Energy Technology Data Exchange (ETDEWEB)

Hofemeister, J [Akademie der Wissenschaften der DDR, Gatersleben. Zentralinstitut fuer Genetik und Kulturpflanzenforschung

1977-02-28

The amount of and the molecular weight of newly synthesized DNA (piDNA) as well as its repair after uv irradiation in excision-proficient strains of P.mirabilis and E.coli K12 have been compared. A fraction of post-replication repair (PRR) in P.mirabilis is found to be dependent on de novo protein synthesis after uv irradiation. Pre-irradiation by uv and pre-treatment with nalidixic acid increase the efficiency of post-irradiation replication and PRR even in the presence of chloramphenicol. An inducible repair function in P.mirabilis is supposed to stimulate post-irradiation replication and repair.

Proteomic and functional analyses reveal MAPK1 regulates milk protein synthesis.

Science.gov (United States)

Lu, Li-Min; Li, Qing-Zhang; Huang, Jian-Guo; Gao, Xue-Jun

2012-12-27

L-Lysine (L-Lys) is an essential amino acid that plays fundamental roles in protein synthesis. Many nuclear phosphorylated proteins such as Stat5 and mTOR regulate milk protein synthesis. However, the details of milk protein synthesis control at the transcript and translational levels are not well known. In this current study, a two-dimensional gel electrophoresis (2-DE)/MS-based proteomic technology was used to identify phosphoproteins responsible for milk protein synthesis in dairy cow mammary epithelial cells (DCMECs). The effect of L-Lys on DCMECs was analyzed by CASY technology and reversed phase high performance liquid chromatography (RP-HPLC). The results showed that cell proliferation ability and β-casein expression were enhanced in DCMECs treated with L-Lys. By phosphoproteomics analysis, six proteins, including MAPK1, were identified up-expressed in DCMECs treated with 1.2 mM L-Lys for 24 h, and were verified by quantitative real-time PCR (qRT-PCR) and western blot. Overexpression and siRNA inhibition of MAPK1 experiments showed that MAPK1 upregulated milk protein synthesis through Stat5 and mTOR pathway. These findings that MAPK1 involves in regulation of milk synthesis shed new insights for understanding the mechanisms of milk protein synthesis.

Understanding Protein Synthesis: An Interactive Card Game Discussion

Science.gov (United States)

Lewis, Alison; Peat, Mary; Franklin, Sue

2005-01-01

Protein synthesis is a complex process and students find it difficult to understand. This article describes an interactive discussion "game" used by first year biology students at the University of Sydney. The students, in small groups, use the game in which the processes of protein synthesis are actioned by the students during a…