Articles de revues : « Effetto SNARC »

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Schroeder, Philipp Alexander, Hans-Christoph Nuerk et Christian Plewnia. « Space in numerical and ordinal information : A common construct ? » Journal of Numerical Cognition 3, n^o 2 (22 décembre 2017) : 164–81. http://dx.doi.org/10.5964/jnc.v3i2.40.

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Space is markedly involved in numerical processing, both explicitly in instrumental learning and implicitly in mental operations on numbers. Besides action decisions, action generations, and attention, the response-related effect of numerical magnitude or ordinality on space is well documented in the Spatial-Numerical Associations of Response Codes (SNARC) effect. Here, right- over left-hand responses become relatively faster with increasing magnitude positions. However, SNARC-like behavioral signatures in non-numerical tasks with ordinal information were also observed and inspired new models integrating seemingly spatial effects of ordinal and numerical metrics. To examine this issue further, we report a comparison between numerical SNARC and ordinal SNARC-like effects to investigate group-level characteristics and individual-level deductions from generalized views, i.e., convergent validity. Participants solved order-relevant (before/after classification) and order-irrelevant tasks (font color classification) with numerical stimuli 1-5, comprising both magnitude and order information, and with weekday stimuli, comprising only ordinal information. A small correlation between magnitude- and order-related SNARCs was observed, but effects are not pronounced in order-irrelevant color judgments. On the group level, order-relevant spatial-numerical associations were best accounted for by a linear magnitude predictor, whereas the SNARC effect for weekdays was categorical. Limited by the representativeness of these tasks and analyses, results are inconsistent with a single amodal cognitive mechanism that activates space in mental processing of cardinal and ordinal information alike. A possible resolution to maintain a generalized view is proposed by discriminating different spatial activations, possibly mediated by visuospatial and verbal working memory, and by relating results to findings from embodied numerical cognition.

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Schwarz, Wolf, et Dana Müller. « Spatial Associations in Number-Related Tasks ». Experimental Psychology 53, n^o 1 (janvier 2006) : 4–15. http://dx.doi.org/10.1027/1618-3169.53.1.4.

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Bimanual parity judgments of numerically small (large) digits are faster with the left (right) hand (the SNARC effect; Dehaene, Bossini, & Giraux, 1993 ). According to one explanation, this effect is culturally derived and reflects ontogenetic influences such as the direction of written language; it might therefore be limited to, or at least be larger with, pairs of lateralized effectors which are instrumental to the production and comprehension of written language. We report two experiments which test for SNARC effects with pedal responses, and compare these effects to manual results. Pedal responses yielded highly systematic SNARC effects; furthermore, these effects did not differ from manual SNARC effects. These results argue against accounts in which the SNARC effect is specific for effectors that are habitually associated with the production or comprehension of written language.

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Priftis, Konstantinos, Marco Zorzi, Francesca Meneghello, Roberto Marenzi et Carlo Umiltà. « Explicit versus Implicit Processing of Representational Space in Neglect : Dissociations in Accessing the Mental Number Line ». Journal of Cognitive Neuroscience 18, n^o 4 (1 avril 2006) : 680–88. http://dx.doi.org/10.1162/jocn.2006.18.4.680.

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The present study investigated the effects of left hemispatial neglect on two tasks activating the mental number line (MNL). Six patients with left neglect performed a mental number bisection task and a modified version of the Spatial Numerical Association of Response Codes (SNARC) task. Effects of left neglect were observed in the number bisection task, but not in the SNARC task. We argue that the dissociation between number bisection and SNARC resembles, in the representational space of the MNL, previously reported dissociations on neglect between explicit knowledge (assessed by direct tasks) and implicit knowledge (assessed by indirect tasks).

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Zhao, Liang, Yang Bai, Jie Ma et Yonghui Wang. « Local Control Mechanisms of Implicit and Explicit Conflicts ». Experimental Psychology 62, n^o 3 (7 mai 2015) : 153–60. http://dx.doi.org/10.1027/1618-3169/a000281.

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Congruency sequence effects are observed when the congruency effects following incongruent trials are smaller than those following congruent trials. It is typically assumed that such flexible adjustments are evidence of cognitively controlled dynamic modulations. The present study investigated whether cognitive control acts locally or globally when implicit and explicit conflicts exist simultaneously within a system. The implicit SNARC task and explicit Simon task were combined in a single task. The results showed that congruency effects of one type (e.g., SNARC effect) were only smaller following an incongruent trial of the same type (e.g., SNARC effect), but not when following an incongruent trial of the other type (e.g., Simon effect). These results indicate the operation of local control mechanisms triggered by implicit and explicit conflicts.

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Cleland, Alexandra A., Kathryn Corsico, Kirstin White et Rebecca Bull. « Non-symbolic numerosities do not automatically activate spatial–numerical associations : Evidence from the SNARC effect ». Quarterly Journal of Experimental Psychology 73, n^o 2 (9 septembre 2019) : 295–308. http://dx.doi.org/10.1177/1747021819875021.

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The SNARC (spatial–numerical association of response codes) effect is the finding that people are generally faster to respond to smaller numbers with left-sided responses and larger numbers with right-sided responses. The SNARC effect has been widely reported for responses to symbolic representations of number such as digits. However, there is mixed evidence as to whether it occurs for non-symbolic representations of number, particularly when magnitude is irrelevant to the task. Mitchell et al. reported a SNARC effect when participants were asked to make orientation decisions to arrays of one-to-nine triangles (pointing upwards vs. pointing downwards) and concluded that SNARC effects occur for non-symbolic, non-canonical representations of number. They additionally reported that this effect was stronger in the subitising range. However, here we report four experiments that do not replicate either of these findings. Participants made upwards/inverted decisions to one-to-nine triangles where total surface area was either controlled across numerosities (Experiments 1, 2, and 4) or increased congruently with numerosity (Experiment 3). There was no evidence of a SNARC effect either across the full range or within the subset of the subitising range. The results of Experiment 4 (in which we presented the original stimuli of Mitchell et al.) suggested that visual properties of non-symbolic displays can prompt SNARC-like effects driven by visual cues rather than numerosity. Taken in the context of other recent findings, we argue that non-symbolic representations of number do not offer a direct and automatic route to numerical–spatial associations.

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Lopiccolo, Dominique, et Charles B. Chang. « Cultural factors weaken but do not reverse left-to-right spatial biases in numerosity processing : Data from Arabic and English monoliterates and Arabic-English biliterates ». PLOS ONE 16, n^o 12 (16 décembre 2021) : e0261146. http://dx.doi.org/10.1371/journal.pone.0261146.

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Directional response biases due to a conceptual link between space and number, such as a left-to-right hand bias for increasing numerical magnitude, are known as the SNARC (Spatial-Numerical Association of Response Codes) effect. We investigated how the SNARC effect for numerosities would be influenced by reading-writing direction, task instructions, and ambient visual environment in four literate populations exemplifying opposite reading-writing cultures—namely, Arabic (right-to-left script) and English (left-to-right script). Monoliterates and biliterates in Jordan and the U.S. completed a speeded numerosity comparison task to assess the directionality and magnitude of a SNARC effect in their numerosity processing. Monoliterates’ results replicated previously documented effects of reading-writing direction and task instructions: the SNARC effect found in left-to-right readers was weakened in right-to-left readers, and the left-to-right group exhibited a task-dependency effect (SNARC effect in the smaller condition, reverse SNARC effect in the larger condition). Biliterates’ results did not show a clear effect of environment; instead, both biliterate groups resembled English monoliterates in showing a left-to-right, task-dependent SNARC effect, albeit weaker than English monoliterates’. The absence of significant biases in all Arabic-reading groups (biliterates and Arabic monoliterates) points to a potential conflict between distinct spatial-numerical mapping codes. This view is explained in terms of the proposed Multiple Competing Codes Theory (MCCT), which posits three distinct spatial-numerical mapping codes (innate, cardinal, ordinal) during numerical processing—each involved at varying levels depending on individual and task factors.

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Simmons, Fiona, Thomas Gallagher-Mitchell et Ruth S. Ogden. « Response-irrelevant number, duration, and extent information triggers the SQARC effect : Evidence from an implicit paradigm ». Quarterly Journal of Experimental Psychology 72, n^o 9 (3 avril 2019) : 2261–71. http://dx.doi.org/10.1177/1747021819839413.

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Spatial–Numerical Association of Response Codes (SNARC) and Spatial–Quantity Association of Response Codes (SQARC) effects are evident when people produce faster left-sided responses to smaller numbers, sizes, and durations and faster right-sided responses to larger numbers, sizes, and durations. SQARC effects have typically been demonstrated in paradigms where the explicit processing of quantity information is required for successful task completion. The current study tested whether the implicit presentation of task-irrelevant magnitude information could trigger a SQARC effect as has been demonstrated previously when task-irrelevant information triggers a SNARC effect. In Experiment 1, participants ( n = 20) made orientation judgements for triangles varying in numerosity and physical extent. In Experiment 2, participants ( n = 20) made orientation judgements for triangles varying in numerosity and for a triangle preceded by a delay of varying duration. SNARC effects were observed for the numerosity conditions of Experiments 1 and 2 replicating Mitchell et al. SQARC effects were also demonstrated for physical extent and for duration. These findings demonstrate that SQARC effects can be implicitly triggered by the presentation of the task-irrelevant magnitude.

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Fischer, Martin H., Samuel Shaki et Alexander Cruise. « It Takes Just One Word to Quash a SNARC ». Experimental Psychology 56, n^o 5 (janvier 2009) : 361–66. http://dx.doi.org/10.1027/1618-3169.56.5.361.

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Our directional reading habit seems to contribute to the widely reported association of small numbers with left space and larger numbers with right space (the spatial-numerical association of response codes, SNARC, effect). But how can this association be so flexible when reading habits are not? To address this question, we asked bilingual Russian-Hebrew readers to classify numbers by parity and alternated the number format from trial to trial between written words and Arabic digits. The number words were randomly printed in either Cyrillic or Hebrew script, thus inducing left-to-right or right-to-left reading, respectively. Classification performance indicated that the digits were spatially mapped when they followed a Russian word but not when they followed a Hebrew word. An auditory control experiment revealed left-to-right SNARC effects with different strengths in both languages. These results suggest that the SNARC effect reflects recent spatial experiences, cross-modal associations, and long-standing directional habits but not an attribute of the number concepts themselves.

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Prpić, Valter, et Dražen Domijan. « Linear representation of pitch height in the SMARC effect ». Psihologijske teme 27, n^o 3 (2018) : 437–52. http://dx.doi.org/10.31820/pt.27.3.5.

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The Spatial-Musical Association of Response Codes (SMARC) effect consists in faster and more accurate responses to low (vs. high) pitched tones when they are executed in the bottom/left (vs. top/right) space. This phenomenon has many similarities with the Spatial-Numerical Association of Response Codes (SNARC) effect which, however, has been more extensively investigated and theoretically debated. The first theoretical account of the SNARC effect suggests the existence of a direct mapping between the position of a number on a mental number line and the external space of response execution. Conversely, following accounts claim that numbers are automatically categorized in two opposing categories (e.g., small vs. large) and then associated to response alternatives (left vs. right). A modified task, consisting in unimanual close/far responses relative to a reference key, has been employed to disentangle between the opposite theoretical accounts of the SNARC effect. However, this modified task has never been applied to pitch height and currently there are no specific theoretical accounts for the SMARC effect. The aim of this study is to fill this gap of knowledge. Contrary to what has been found for numbers, our data are more in line with the "direct mapping" account and suggests a linear representation of pitch height. Our data suggest that SNARC and SMARC effects might have different origins and might require different theoretical accounts.

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Schweiter, Martin, Monika Weinhold Zulauf et Michael von Aster. « Die Entwicklung räumlicher Zahlenrepräsentationen und Rechenfertigkeiten bei Kindern ». Zeitschrift für Neuropsychologie 16, n^o 2 (janvier 2005) : 105–13. http://dx.doi.org/10.1024/1016-264x.16.2.105.

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Zusammenfassung: Hintergrund: Die Repräsentation der Größe von Zahlen in einem von links nach rechts orientierten mentalen Zahlenstrahl wurde bei Erwachsenen mit dem SNARC-Effektes dargestellt (Spatial Numerical Association of Response Codes: schnellere Reaktion linke Hand bei kleinen Zahlen und rechte Hand bei großen Zahlen; Dehaene, Bossini & Giraux; 1993 ). Fragestellung: Die Studie untersucht die Frage, ob SNARC-Effekte (SE) schon bei Kindern der 2. Klasse nachweisbar sind und welche Zusammenhänge zu Rechenleistungen bestehen. Methode: Untersucht wurden N = 113 Kinder aus einer repräsentativen Stichprobe aus dem Kanton Zürich. Die Überprüfung von Fertigkeiten der Zahlenverarbeitung erfolgte longitudinal im Kindergarten und in der 2. Klasse. Ebenfalls zum zweiten Testzeitpunkt erfolgte die Durchführung des computergestützten SNARC-Paradigmas. Ergebnisse/Diskussion: Etwa ein Drittel der Kinder zeigten einen SE. Über die gesamte Stichprobe ließ sich kein signifikanter Einfluss des SE auf die Testleistung nachweisen, es besteht jedoch eine signifikante Wechselwirkung mit dem Geschlecht. Bei Knaben korreliert der SE positiv, bei Mädchen negativ mit der Testleistung. Die Ergebnisse werden in Hinblick auf geschlechtsspezifische Aspekte der Entwicklung kognitiver Denkstile diskutiert.

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Shi, Xia, Xunbing Shen et Xiuying Qian. « Grasping and Pointing — Visual Conflict and Interference ». Multisensory Research 31, n^o 5 (2018) : 439–54. http://dx.doi.org/10.1163/22134808-00002576.

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There have been many debates of the two-visual-systems (whatvs. how or perceptionvs. action) hypothesis that was proposed by Goodale and his colleagues. Many researchers have provided a variety of evidence for or against the hypothesis. For instance, a study performed by Agliotiet al. offered good evidence for the two-visual-systems theory using the Ebbinghaus illusion, but some researchers who used other visual illusions failed to find consistent results. Therefore, we used a perceptual task of conflict or interference to test this hypothesis. If the conflict or interference in perception had an influence on the processing of perception alone and did not affect the processing of action, we could infer that the two visual systems are separated, and vice versa. In the current study, we carried out two experiments which employed the Stroop, Garner and SNARC paradigms and used graspable 3-D Arabic numerals. We aimed to find if the effects resulting from perceptual conflicts or interferences would affect participants’ grasping and pointing. The results showed that the interaction between Stroop and numeral order (ascending or descending, or SNARC) was significant, and the SNARC effect significantly affected action, but the main effects of Stroop and Garner interference were not significant. The results indicated that, to some degree, perceptual conflict affects action processing. The results did not provide evidence for two separate visual systems.

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Torng, Thomas, Hongki Song et William Wickner. « Asymmetric Rab activation of vacuolar HOPS to catalyze SNARE complex assembly ». Molecular Biology of the Cell 31, n^o 10 (1 mai 2020) : 1060–68. http://dx.doi.org/10.1091/mbc.e20-01-0019.

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Rab proteins are known to recruit effector complexes for membrane fusion. Using pure yeast vacuole fusion proteins, we now show that the Rab Ypt7 and vacuolar lipids allosterically activate the effector HOPS to catalyze SNARE complex assembly when the R-SNARE is bound to the same membrane as Ypt7.

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Yang, Yoosoo, Jung-Mi Oh, Paul Heo, Jae Yoon Shin, Byoungjae Kong, Jonghyeok Shin, Ji-Chun Lee et al. « Polyphenols differentially inhibit degranulation of distinct subsets of vesicles in mast cells by specific interaction with granule-type-dependent SNARE complexes ». Biochemical Journal 450, n^o 3 (28 février 2013) : 537–46. http://dx.doi.org/10.1042/bj20121256.

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Anti-allergic effects of dietary polyphenols were extensively studied in numerous allergic disease models, but the molecular mechanisms of anti-allergic effects by polyphenols remain poorly understood. In the present study, we show that the release of granular cargo molecules, contained in distinct subsets of granules of mast cells, is specifically mediated by two sets of SNARE (soluble N-ethylmaleimide-sensitive factor attachment protein receptor) proteins, and that various polyphenols differentially inhibit the formation of those SNARE complexes. Expression analysis of RBL-2H3 cells for 11 SNARE genes and a lipid mixing assay of 24 possible combinations of reconstituted SNAREs indicated that the only two active SNARE complexes involved in mast cell degranulation are Syn (syntaxin) 4/SNAP (23 kDa synaptosome-associated protein)-23/VAMP (vesicle-associated membrane protein) 2 and Syn4/SNAP-23/VAMP8. Various polyphenols selectively or commonly interfered with ternary complex formation of these two SNARE complexes, thereby stopping membrane fusion between granules and plasma membrane. This led to the differential effect of polyphenols on degranulation of three distinct subsets of granules. These results suggest the possibility that formation of a variety of SNARE complexes in numerous cell types is controlled by polyphenols which, in turn, might regulate corresponding membrane trafficking.

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Chen, Long-En, Anthony V. Seaber, Rima M. Nasser, Jonathan S. Stamler et James R. Urbaniak. « Effects ofS-nitroso-N-acetylcysteine on contractile function of reperfused skeletal muscle ». American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 274, n^o 3 (1 mars 1998) : R822—R829. http://dx.doi.org/10.1152/ajpregu.1998.274.3.r822.

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The ultimate goal of replantation and microsurgical reconstructive operations is to regain or improve impaired function of the tissue. However, the data related to the influence of NO on tissue function are limited. This study evaluated the effects of the NO donor S-nitroso- N-acetylcysteine (SNAC) on contractile function of skeletal muscle during reperfusion. Forty-nine rats were divided into six groups. The extensor digitorum longus (EDL) muscles in groups I and II were not subjected to ischemia-reperfusion but were treated with a low (100 nmol/min) or high (1 μmol/min) dose of SNAC. In groups III- V, the EDL underwent 3 h of ischemia and 3 h of reperfusion and was also treated with low (100 nmol/min) or high doses (1 or 5 μmol/min) of SNAC. Group VI was a phosphate-buffered saline (PBS)-treated control group. Twenty additional animals were used to document systemic effects of SNAC and PBS only. SNAC or PBS was infused for 6.5 h, beginning 30 min before ischemia and continuing throughout the duration of reperfusion. Contractile testing compared the maximal twitch force, isometric tetanic contractile forces, fatigue, and fatigue half time of the experimental EDL and the contralateral nontreated EDL. The findings indicate that 1) SNAC does not influence contractile function of EDL muscle not subjected to ischemia-reperfusion, 2) SNAC significantly protects the contractile function of ischemic skeletal muscle against reperfusion injury in the early reperfusion period, and 3) the protective role of SNAC is critically dosage dependent; protection is lost at higher doses. The conclusion from this study is that supplementation with exogenous NO exerts a protective effect on the tissue against reperfusion injury.

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Gevers, Wim, Bernie Caessens et Wim Fias. « Towards a common processing architecture underlying Simon and SNARC effects ». European Journal of Cognitive Psychology 17, n^o 5 (septembre 2005) : 659–73. http://dx.doi.org/10.1080/09541440540000112.

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Achuthan, Adrian, Paul Masendycz, Jamie A. Lopez, Thao Nguyen, David E. James, Matthew J. Sweet, John A. Hamilton et Glen M. Scholz. « Regulation of the Endosomal SNARE Protein Syntaxin 7 by Colony-Stimulating Factor 1 in Macrophages ». Molecular and Cellular Biology 28, n^o 20 (18 août 2008) : 6149–59. http://dx.doi.org/10.1128/mcb.00220-08.

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ABSTRACT Colony-stimulating factor 1 (CSF-1) is the main growth factor controlling the development of macrophages from myeloid progenitor cells. However, CSF-1 also regulates some of the key effector functions of macrophages (e.g., phagocytosis and cytokine secretion). The endosomal SNARE protein syntaxin 7 (Stx7) regulates vesicle trafficking events involved in phagocytosis and cytokine secretion. Therefore, we investigated the ability of CSF-1 to regulate Stx7. CSF-1 upregulated Stx7 expression in primary mouse macrophages; it also upregulated expression of its SNARE partners Vti1b and VAMP8 but not Stx8. Additionally, CSF-1 induced the rapid serine phosphorylation of Stx7 and enhanced its binding to Vti1b, Stx8, and VAMP8. Bioinformatics analysis and results from experiments with kinase inhibitors suggested the CSF-1-induced phosphorylation of Stx7 was mediated by protein kinase C and Akt in response to phosphatidylinositol 3-kinase activation. Based on mutagenesis studies, CSF-1 appeared to increase the binding of Stx7 to its SNARE partners by inducing the phosphorylation of serine residues in the Habc domain and/or “linker” region of Stx7. Thus, CSF-1 is a key regulator of Stx7 expression and function in macrophages. Furthermore, the effects of CSF-1 on Stx7 may provide a mechanism for the regulation of macrophage effector functions by CSF-1.

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Zhang, Zhen, Enfu Hui, Edwin R. Chapman et Meyer B. Jackson. « Regulation of Exocytosis and Fusion Pores by Synaptotagmin-Effector Interactions ». Molecular Biology of the Cell 21, n^o 16 (15 août 2010) : 2821–31. http://dx.doi.org/10.1091/mbc.e10-04-0285.

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Synaptotagmin (syt) serves as a Ca2+ sensor in the release of neurotransmitters and hormones. This function depends on the ability of syt to interact with other molecules. Syt binds to phosphatidylserine (PS)-containing lipid bilayers as well as to soluble N-ethylmaleimide sensitive factor receptors (SNAREs) and promotes SNARE assembly. All these interactions are regulated by Ca2+, but their specific roles in distinct kinetic steps of exocytosis are not well understood. To explore these questions we used amperometry recording from PC12 cells to investigate the kinetics of exocytosis. Syt isoforms and syt I mutants were overexpressed to perturb syt-PS and syt-SNARE interactions to varying degrees and evaluate the effects on fusion event frequency and the rates of fusion pore transitions. Syt I produced more rapid dilation of fusion pores than syt VII or syt IX, consistent with its role in synchronous synaptic release. Stronger syt-PS interactions were accompanied by a higher frequency of fusion events and more stable fusion pores. By contrast, syt-SNARE interactions and syt-induced SNARE assembly were uncorrelated with rates of exocytosis. This associates the syt-PS interaction with two distinct kinetic steps in Ca2+ triggered exocytosis and supports a role for the syt-PS interaction in stabilizing open fusion pores.

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Rusconi, Elena, Martynas Dervinis, Frederick Verbruggen et Christopher D. Chambers. « Critical Time Course of Right Frontoparietal Involvement in Mental Number Space ». Journal of Cognitive Neuroscience 25, n^o 3 (mars 2013) : 465–83. http://dx.doi.org/10.1162/jocn_a_00330.

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Neuropsychological, neurophysiological, and neuroimaging studies suggest that right frontoparietal circuits may be necessary for the processing of mental number space, also known as the mental number line (MNL). Here we sought to specify the critical time course of three nodes that have previously been related to MNL processing: right posterior parietal cortex (rPPC), right FEF (rFEF), and right inferior frontal gyrus (rIFG). The effects of single-pulse TMS delivered at 120% distance-adjusted individual motor threshold were investigated in 21 participants, within a window of 0–400 msec (sampling interval = 33 msec) from the onset of a central digit (1–9, 5 excluded). Pulses were delivered in a random order and with equal probability at each time point, intermixed with noTMS trials. To analyze whether and when TMS interfered with MNL processing, we fitted bimodal Gaussian functions to the observed data and measured effects on changes in the Spatial–Numerical Association of Response Codes (SNARC) effect (i.e., an advantage for left- over right-key responses to small numbers and right- over left-key responses to large numbers) and in overall performance efficiency. We found that, during magnitude judgment with unimanual key-press responses, TMS reduced the SNARC effect in the earlier period of the fitted functions (∼25–60 msec) when delivered over rFEF (small and large numbers) and rIFG (small numbers); TMS further reduced the SNARC effect for small numbers in a later period when delivered to rFEF (∼200 msec). In contrast, TMS of rPPC did not interfere with the SNARC effect but generally reduced performance for small numbers and enhanced it for large numbers, thus producing a pattern reminiscent of “neglect” in mental number space. Our results confirm the causal role of an intact right frontoparietal network in the processing of mental number space. They also indicate that rPPC is specifically tied to explicit number magnitude processing and that rFEF and rIFG contribute to interfacing mental visuospatial codes with lateralized response codes. Overall, our findings suggest that both ventral and dorsal frontoparietal circuits are causally involved and functionally connected in the mapping of numbers to space.

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Minchenko, Dmytro O., D. O. Tsymbal, O. P. Yavorovsky, N. V. Solokha et O. H. Minchenko. « Expression of genes encoding IGFBPs, SNARK, CD36, and PECAM1 in the liver of mice treated with chromium disilicide and titanium nitride nanoparticles ». Endocrine Regulations 51, n^o 2 (25 avril 2017) : 84–95. http://dx.doi.org/10.1515/enr-2017-0008.

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AbstractObjective. The aim of the present study was to examine the effect of chromium disilicide and titanium nitride nanoparticles on the expression level of genes encoding important regulatory factors (IGFBP1, IGFBP2, IGFBP3, IGFBP4, IGFBP5, SNARK/NUAK2, CD36, and PECAM1/CD31) in mouse liver for evaluation of possible toxic effects of these nanoparticles.Methods. Male mice received 20 mg chromium disilicide nanoparticles (45 nm) and titanium nitride nanoparticles (20 nm) with food every working day for 2 months. The expression of IGFBP1, IGFBP2, IGFBP3, IGFBP4, IGFBP5, SNARK, CD36, and PECAM1 genes in mouse liver was studied by quantitative polymerase chain reaction.Results. Treatment of mice with chromium disilicide nanoparticles led to down-regulation of the expression of IGFBP2, IGFBP5, PECAM1, and SNARK genes in the liver in comparison with control mice, with more prominent changes for SNARK gene. At the same time, the expression of IGFBP3 and CD36 genes was increased in mouse liver upon treatment with chromium disilicide nanoparticles. We have also shown that treatment with titanium nitride nanoparticles resulted in down-regulation of the expression of IGFBP2 and SNARK genes in the liver with more prominent changes for SNARK gene. At the same time, the expression of IGFBP3, IGFBP4, and CD36 genes was increased in the liver of mice treated with titanium nitride nanoparticles. Furthermore, the effect of chromium disilicide nanoparticles on IGFBP2 and CD36 genes expression was significantly stronger as compared to titanium nitride nanoparticles.Conclusions. The results of this study demonstrate that chromium disilicide and titanium nitride nanoparticles have variable effects on the expression of IGFBP2, IGFBP3, IGFBP4, IGFBP5, SNARK, CD36, and PECAM1 genes in mouse liver, which may reflect the genotoxic activities of the studied nanoparticles.

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Starai, Vincent J., Christopher M. Hickey et William Wickner. « HOPS Proofreads the trans-SNARE Complex for Yeast Vacuole Fusion ». Molecular Biology of the Cell 19, n^o 6 (juin 2008) : 2500–2508. http://dx.doi.org/10.1091/mbc.e08-01-0077.

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The fusion of yeast vacuoles, like other organelles, requires a Rab-family guanosine triphosphatase (Ypt7p), a Rab effector and Sec1/Munc18 (SM) complex termed HOPS (homotypic fusion and vacuole protein sorting), and soluble N-ethylmaleimide-sensitive factor attachment protein receptors (SNAREs). The central 0-layer of the four bundled vacuolar SNAREs requires the wild-type three glutaminyl (Q) and one arginyl (R) residues for optimal fusion. Alterations of this layer dramatically increase the Km value for SNAREs to assemble trans-SNARE complexes and to fuse. We now find that added purified HOPS complex strongly suppresses the fusion of vacuoles bearing 0-layer alterations, but it has little effect on the fusion of vacuoles with wild-type SNAREs. HOPS proofreads at two levels, inhibiting the formation of trans-SNARE complexes with altered 0-layers and suppressing the ability of these mismatched 0-layer trans-SNARE complexes to support membrane fusion. HOPS proofreading also extends to other parts of the SNARE complex, because it suppresses the fusion of trans-SNARE complexes formed without the N-terminal Phox homology domain of Vam7p (Qc). Unlike some other SM proteins, HOPS proofreading does not require the Vam3p (Qa) N-terminal domain. HOPS thus proofreads SNARE domain and N-terminal domain structures and regulates the fusion capacity of trans-SNARE complexes, only allowing full function for wild-type SNARE configurations. This is the most direct evidence to date that HOPS is directly involved in the fusion event.

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Fischer, Ursula, Martin H. Fischer, Stefan Huber, Sarah Strauß et Korbinian Moeller. « The influence of number magnitude on continuous swiping movements ». Journal of Numerical Cognition 4, n^o 2 (7 septembre 2018) : 297–316. http://dx.doi.org/10.5964/jnc.v4i2.135.

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There is accumulating evidence that numerical information influences the way in which we perform bodily movements. Specifically, the idea that our cognitive representations of numbers and space interact is supported by systematic associations of space with both number magnitude (SNARC effect) and number parity (MARC effect). However, whether this influence is bound to the left or right side of space or to the hand with which we perform the movement remains debated. One novel and interesting way to disentangle these factors is to use movement responses in which hand and movement direction can be dissociated. In the present study, participants moved a central object to the left or right side on a touchscreen with their index fingers as response to a parity judgment and magnitude classification task. We observed significant SNARC effects in both tasks. Number magnitude and response direction interacted, but magnitude and response hand did not. This indicated that the SNARC effect can be independent of the responding hand. Importantly, however, a MARC effect was observed not only in an interaction between response direction and parity, but also in an interaction between response hand and parity, suggesting that response hand plays a role in the interaction between physical space and parity. Additionally, number magnitude influenced the amplitude of participants’ response movements, with larger numbers eliciting longer movements. These results indicate that space, magnitude and parity interact on different levels that can be unraveled in a paradigm utilizing continuous movements such as swiping.

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Zhou, Xinlin, Chaoran Shen, Leinian Li, Dawei Li et Jiaxin Cui. « Mental Numerosity Line in the Human’s Approximate Number System ». Experimental Psychology 63, n^o 3 (juin 2016) : 169–79. http://dx.doi.org/10.1027/1618-3169/a000324.

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Abstract. Previous studies have demonstrated existence of a mental line for symbolic numbers (e.g., Arabic digits). For nonsymbolic number systems, however, it remains unresolved whether a spontaneous spatial layout of numerosity exists. The current experiment investigated whether SNARC-like (Spatial-Numerical Association of Response Codes) effects exist in approximate processing of numerosity, as well as of size and density. Participants were asked to judge whether two serially presented stimuli (i.e., dot arrays, pentagons) were the same regarding numbers of dots, sizes of the pentagon, or densities of dots. Importantly, two confounds that were overlooked by most previous studies were controlled in this study: no ordered numerosity was presented, and only numerosity in the approximate number system (beyond the subitizing range) was used. The results demonstrated that there was a SNARC-like effect only in the numerosity-matching task. The results suggest that numerosity could be spontaneously aligned to a left-to-right oriented mental line according to magnitude information in human’s approximate number system.

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Kweon, Youngseok, Anca Rothe, Elizabeth Conibear et Tom H. Stevens. « Ykt6p Is a Multifunctional Yeast R-SNARE That Is Required for Multiple Membrane Transport Pathways to the Vacuole ». Molecular Biology of the Cell 14, n^o 5 (mai 2003) : 1868–81. http://dx.doi.org/10.1091/mbc.e02-10-0687.

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Intracellular membrane fusion requires that membrane-bound soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) proteins on both vesicle and target membranes form a highly specific complex necessary to bring the membranes close in space. Ykt6p is a yeast R-SNARE protein that has been implicated in retrograde transport to the cis-Golgi compartment. Ykt6p has been also been found to fractionate with vacuole membranes and participate in a vacuolar SNARE complex in homotypic vacuole fusion. To investigate the role of Ykt6p in membrane traffic to the vacuole we generated temperature-sensitive mutations in YKT6. One mutation produces an early Golgi block to secretion, and overexpression of the SNARE protein Sft1p suppresses the growth and secretion defects of this mutation. These results are consistent with Ykt6p and Sft1p participating in a SNARE complex associated with retrograde transport to the cis-Golgi. A second set of mutations in YKT6 specifically affects post-Golgi membrane traffic to the vacuole, and the effects of these mutations are not suppressed by Sft1p overexpression. Defects are seen in carboxypeptidase Y sorting, alkaline phosphatase transport, and aminopeptidase I delivery, and in one mutant, overexpression of the SNARE protein Nyv1p suppresses the alkaline phosphatase transport defect. By mutationally separating early and late requirements for Ykt6p, our findings have revealed that Ykt6p is a R-SNARE protein that functions directly in the three biosynthetic pathways to the vacuole.

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Aikawa, Yoshikatsu, Kara L. Lynch, Kristin L. Boswell et Thomas F. J. Martin. « A Second SNARE Role for Exocytic SNAP25 in Endosome Fusion ». Molecular Biology of the Cell 17, n^o 5 (mai 2006) : 2113–24. http://dx.doi.org/10.1091/mbc.e06-01-0074.

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Soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) proteins play key roles in membrane fusion, but their sorting to specific membranes is poorly understood. Moreover, individual SNARE proteins can function in multiple membrane fusion events dependent upon their trafficking itinerary. Synaptosome-associated protein of 25 kDa (SNAP25) is a plasma membrane Q (containing glutamate)-SNARE essential for Ca2+-dependent secretory vesicle–plasma membrane fusion in neuroendocrine cells. However, a substantial intracellular pool of SNAP25 is maintained by endocytosis. To assess the role of endosomal SNAP25, we expressed botulinum neurotoxin E (BoNT E) light chain in PC12 cells, which specifically cleaves SNAP25. BoNT E expression altered the intracellular distribution of SNAP25, shifting it from a perinuclear recycling endosome to sorting endosomes, which indicates that SNAP25 is required for its own endocytic trafficking. The trafficking of syntaxin 13 and endocytosed cargo was similarly disrupted by BoNT E expression as was an endosomal SNARE complex comprised of SNAP25/syntaxin 13/vesicle-associated membrane protein 2. The small-interfering RNA-mediated down-regulation of SNAP25 exerted effects similar to those of BoNT E expression. Our results indicate that SNAP25 has a second function as an endosomal Q-SNARE in trafficking from the sorting endosome to the recycling endosome and that BoNT E has effects linked to disruption of the endosome recycling pathway.

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Lin, Haijun, Qi Chen, Caijuan Li, Aifen Zheng, Lei Yang, Jiemin Hong, Hanqing Chen, Xuni He et Wuna Feng. « Deep Learning-Based Automatic Detection of Rectal Polyps Using Abdominal CT Images Guided by Cold Snare Polypectomy ». Scientific Programming 2021 (5 juillet 2021) : 1–7. http://dx.doi.org/10.1155/2021/1179016.

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The study drew attention to the therapeutic effects of cold snare polypectomy guided by a deep convolutional neural network- (CNN-) based abdominal CT and hot snare polypectomy (HSP) on colonic and rectal polyps. Specifically, 90 patients were enrolled into a blank group, a control (Ctrl) group, and an experimental group. The blank group accepted HSP, the Ctrl accepted cold snare polypectomy, and the experimental group accepted cold snare polypectomy guided by deep CNN-based CT images. It was found that the experimental group had the lowest false-positive rate (9.2%) in polyp detection in contrast with the Ctrl (21.4%) and the blank group (52.3%) P < 0.05 . The complete resection rate of large polyps in the experimental group was the highest P < 0.05 , and its operation time (2.91 ± 0.75 min) was obviously shorter versus the blank group (6.18 ± 1.19 min) P < 0.05 . In conclusion, the cold snare polypectomy under the guidance of deep CNN-based CT has a relatively high complete resection rate and detection accuracy of polyps with a low complication rate, which can be adopted clinically.

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Shi, Xingqi, Partho Halder, Halenur Yavuz, Reinhard Jahn et Howard A. Shuman. « Direct targeting of membrane fusion by SNARE mimicry : Convergent evolution of Legionella effectors ». Proceedings of the National Academy of Sciences 113, n^o 31 (19 juillet 2016) : 8807–12. http://dx.doi.org/10.1073/pnas.1608755113.

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Legionella pneumophila, the Gram-negative pathogen causing Legionnaires’ disease, infects host cells by hijacking endocytic pathways and forming a Legionella-containing vacuole (LCV) in which the bacteria replicate. To promote LCV expansion and prevent lysosomal targeting, effector proteins are translocated into the host cell where they alter membrane traffic. Here we show that three of these effectors [LegC2 (Legionella eukaryotic-like gene C2)/YlfB (yeast lethal factor B), LegC3, and LegC7/YlfA] functionally mimic glutamine (Q)-SNARE proteins. In infected cells, the three proteins selectively form complexes with the endosomal arginine (R)-SNARE vesicle-associated membrane protein 4 (VAMP4). When reconstituted in proteoliposomes, these proteins avidly fuse with liposomes containing VAMP4, resulting in a stable complex with properties resembling canonical SNARE complexes. Intriguingly, however, the LegC/SNARE hybrid complex cannot be disassembled by N-ethylmaleimide-sensitive factor. We conclude that LegCs use SNARE mimicry to divert VAMP4-containing vesicles for fusion with the LCV, thus promoting its expansion. In addition, the LegC/VAMP4 complex avoids the host’s disassembly machinery, thus effectively trapping VAMP4 in an inactive state.

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Gkikas, Ilias, Ioanna Daskalaki, Konstantinos Kounakis, Nektarios Tavernarakis et Eirini Lionaki. « MitoSNARE Assembly and Disassembly Factors Regulate Basal Autophagy and Aging in C. elegans ». International Journal of Molecular Sciences 24, n^o 4 (20 février 2023) : 4230. http://dx.doi.org/10.3390/ijms24044230.

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SNARE proteins reside between opposing membranes and facilitate vesicle fusion, a physiological process ubiquitously required for secretion, endocytosis and autophagy. With age, neurosecretory SNARE activity drops and is pertinent to age-associated neurological disorders. Despite the importance of SNARE complex assembly and disassembly in membrane fusion, their diverse localization hinders the complete understanding of their function. Here, we revealed a subset of SNARE proteins, the syntaxin SYX-17, the synaptobrevins VAMP-7, SNB-6 and the tethering factor USO-1, to be either localized or in close proximity to mitochondria, in vivo. We term them mitoSNAREs and show that animals deficient in mitoSNAREs exhibit increased mitochondria mass and accumulation of autophagosomes. The SNARE disassembly factor NSF-1 seems to be required for the effects of mitoSNARE depletion. Moreover, we find mitoSNAREs to be indispensable for normal aging in both neuronal and non-neuronal tissues. Overall, we uncover a previously unrecognized subset of SNAREs that localize to mitochondria and propose a role of mitoSNARE assembly and disassembly factors in basal autophagy regulation and aging.

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Geumann, Ulf, Sina Victoria Barysch, Peer Hoopmann, Reinhard Jahn et Silvio O. Rizzoli. « SNARE Function Is Not Involved in Early Endosome Docking ». Molecular Biology of the Cell 19, n^o 12 (décembre 2008) : 5327–37. http://dx.doi.org/10.1091/mbc.e08-05-0457.

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Docking and fusion of transport vesicles constitute elementary steps in intracellular membrane traffic. While docking is thought to be initiated by Rab-effector complexes, fusion is mediated by SNARE (N-ethylmaleimide-sensitive factor [NSF] attachment receptor) proteins. However, it has been recently debated whether SNAREs also play a role in the establishment or maintenance of a stably docked state. To address this question, we have investigated the SNARE dependence of docking and fusion of early endosomes, one of the central sorting compartments in the endocytic pathway. A new, fluorescence-based in vitro assay was developed, which allowed us to investigate fusion and docking in parallel. Similar to homotypic fusion, docking of early endosomes is dependent on the presence of ATP and requires physiological temperatures. Unlike fusion, docking is insensitive to the perturbation of SNARE function by means of soluble SNARE motifs, SNARE-specific Fab fragments, or by a block of NSF activity. In contrast, as expected, docking is strongly reduced by interfering with the synthesis of phosphatidyl inositol (PI)-3 phosphate, with the function of Rab-GTPases, as well as with early endosomal autoantigen 1 (EEA1), an essential tethering factor. We conclude that docking of early endosomes is independent of SNARE function.

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MacDonald, Amy F., Charles J. Billington et Allen S. Levine. « Effects of the opioid antagonist naltrexone on feeding induced by DAMGO in the ventral tegmental area and in the nucleus accumbens shell region in the rat ». American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 285, n^o 5 (novembre 2003) : R999—R1004. http://dx.doi.org/10.1152/ajpregu.00271.2003.

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The nucleus accumbens shell region (sNAcc) and the ventral tegmental area (VTA) are two major nodes in the mesolimbic dopamine pathway, which mediates reward for various survival behaviors, including feeding. Opioids increase and maintain food intake when injected peripherally and centrally. Opioids in the VTA cause increased release of dopamine in the sNAcc, and when injected into either site, cause an increase in food intake. Animals in this study were double cannulated in the VTA and in the sNAcc and injected with various combinations of naltrexone (NTX) (2.5, 5, and 25 μg/side) and Tyr-d-Ala-Gly-(Me)Phe-Gly-ol (DAMGO) (0.1, 0.3, 1, 3, and 5 nmol/side) in both sites. DAMGO was found to dose dependently increase intake to an equal extent when injected into either site. DAMGO-induced increases in food intake when injected into the VTA were blocked to control levels with the highest dose of NTX injected bilaterally into the sNAcc; however, increases in intake when injected into the sNAcc were blocked only partially by the highest dose of NTX injected bilaterally into the VTA. These results indicate opioid-opioid communication between the two sites; however, the communication may be quite indirect, requiring other sites and transmitters to elicit a change in behavior.

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Kawahara, Masaaki, Kiyoyuki Furuse, Nagahisa Kodama, Mitsumasa Ogawara, Shinji Atagi, Takao Kamimori, Mitsunobu Nakao et Nobuyuki Naka. « Endobronchial Electrocautery Using Snare ». Diagnostic and Therapeutic Endoscopy 2, n^o 4 (1 janvier 1996) : 207–10. http://dx.doi.org/10.1155/dte.2.207.

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Between May 1987 and March 1994, upper airway and tracheobronchial electrosurgery with snare was performed in 13 patients (10 men and 3 women), ranging in age from 18 to 87 years. Four patients had benign lesions, and nine had malignant tumors. Total eradication has been achieved in the two patients with benign lesions. Electroexcision of the endobronchial portion of the tumor helped to clear the respiratory airways in all cases with malignant tumors. There has been no major side effects such as bleeding due to this method. Electrocautery is an available economical tool, which helps to diagnose and treat obstructing airway mass lesions.

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Earles, Cynthia A., Jihong Bai, Ping Wang et Edwin R. Chapman. « The tandem C2 domains of synaptotagmin contain redundant Ca2+ binding sites that cooperate to engage t-SNAREs and trigger exocytosis ». Journal of Cell Biology 154, n^o 6 (10 septembre 2001) : 1117–24. http://dx.doi.org/10.1083/jcb.200105020.

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Real-time voltammetry measurements from cracked PC12 cells were used to analyze the role of synaptotagmin–SNARE interactions during Ca2+-triggered exocytosis. The isolated C2A domain of synaptotagmin I neither binds SNAREs nor inhibits norepinephrine secretion. In contrast, two C2 domains in tandem (either C2A-C2B or C2A-C2A) bind strongly to SNAREs, displace native synaptotagmin from SNARE complexes, and rapidly inhibit exocytosis. The tandem C2 domains of synaptotagmin cooperate via a novel mechanism in which the disruptive effects of Ca2+ ligand mutations in one C2 domain can be partially alleviated by the presence of an adjacent C2 domain. Complete disruption of Ca2+-triggered membrane and target membrane SNARE interactions required simultaneous neutralization of Ca2+ ligands in both C2 domains of the protein. We conclude that synaptotagmin–SNARE interactions regulate membrane fusion and that cooperation between synaptotagmin's C2 domains is crucial to its function.

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Frank, Amy E., Charles S. Wingo, Peter M. Andrews, Shana Ageloff, Mark A. Knepper et I. David Weiner. « Mechanisms through which ammonia regulates cortical collecting duct net proton secretion ». American Journal of Physiology-Renal Physiology 282, n^o 6 (1 juin 2002) : F1120—F1128. http://dx.doi.org/10.1152/ajprenal.00266.2001.

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Ammonia stimulates cortical collecting duct (CCD) net bicarbonate reabsorption by activating an apical H+-K+-ATPase through mechanisms that are independent of ammonia's known effects on intracellular pH and active sodium transport. The present studies examined whether this stimulation occurs through soluble N-ethylmaleimide-sensitive fusion attachment receptor (SNARE) protein-mediated vesicle fusion. Rabbit CCD segments were studied using in vitro microperfusion, and transepithelial bicarbonate transport was measured using microcalorimetry. Ammonia's stimulation of bicarbonate reabsorption was blocked by either chelating intracellular calcium with 1,2-bis(2-aminophenoxy)ethane- N,N,N',N'-tetraacetic acid acetoxymethyl ester or by inhibiting microtubule polymerization with colchicine compared with parallel studies performed in the absence of these inhibitors. An inactive structural analog of colchicine, lumicolchicine, did not alter ammonia's stimulation of bicarbonate reabsorption. Tetanus toxin, a zinc endopeptidase specific for vesicle-associated SNARE (v-SNARE) proteins, prevented ammonia from stimulating net bicarbonate reabsorption. Consistent with the functional evidence for v-SNARE involvement, antibodies directed against a conserved region of isoforms 1–3 of the tetanus toxin-sensitive, vesicle-associated membrane protein (VAMP) members of v-SNARE proteins labeled the apical and subapical region of collecting duct intercalated cells. Similarly, antibodies to NSF protein, a protein involved in activation of SNARE proteins for subsequent vesicle fusion, localized to the apical and subapical region of collecting duct intercalated cells. These results indicate that ammonia stimulates CCD bicarbonate reabsorption through an intracellular calcium-dependent, microtubule-dependent, and v-SNARE-dependent mechanism that appears to involve insertion of cytoplasmic vesicles into the apical plasma membrane of CCD intercalated cells.

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Alford, Simon, Heidi Hamm, Shelagh Rodriguez et Zack Zurawski. « Gβγ SNARE Interactions and Their Behavioral Effects ». Neurochemical Research 44, n^o 3 (11 mai 2018) : 636–49. http://dx.doi.org/10.1007/s11064-018-2531-x.

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Chang, Steven Y., Anke Di, Anjaparavanda P. Naren, H. Clive Palfrey, Kevin L. Kirk et Deborah J. Nelson. « Mechanisms of CFTR regulation by syntaxin 1A and PKA ». Journal of Cell Science 115, n^o 4 (15 février 2002) : 783–91. http://dx.doi.org/10.1242/jcs.115.4.783.

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Activation of the chloride selective anion channel CFTR is stimulated by cAMP-dependent phosphorylation and is regulated by the target membrane t-SNARE syntaxin 1A. The mechanism by which SNARE proteins modulate CFTR in secretory epithelia is controversial. In addition, controversy exists as to whether PKA activates CFTR-mediated Cl- currents (ICFTR) by increasing the number of channels in the plasma membrane and/or by stimulating membrane-resident channels. SNARE proteins play a well known role in exocytosis and have recently been implicated in the regulation of ion channels; therefore this investigation sought to resolve two related issues:(a) is PKA activation or SNARE protein modulation of CFTR linked to changes in membrane turnover and (b) does syntaxin 1A modulate CFTR via direct effects on the gating of channels residing in the plasma membrane versus alterations in membrane traffic. Our data demonstrate that syntaxin 1A inhibits CFTR as a result of direct protein-protein interactions that decrease channel open probability (Po) and serves as a model for other SNARE protein-ion channel interactions. We also show that PKA activation can enhance membrane trafficking in some epithelial cell types, and this is independent from CFTR activation or syntaxin 1A association.

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Colling, Lincoln J., Dénes Szűcs, Damiano De Marco, Krzysztof Cipora, Rolf Ulrich, Hans-Christoph Nuerk, Mojtaba Soltanlou et al. « Registered Replication Report on Fischer, Castel, Dodd, and Pratt (2003) ». Advances in Methods and Practices in Psychological Science 3, n^o 2 (juin 2020) : 143–62. http://dx.doi.org/10.1177/2515245920903079.

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The attentional spatial-numerical association of response codes (Att-SNARC) effect (Fischer, Castel, Dodd, & Pratt, 2003)—the finding that participants are quicker to detect left-side targets when the targets are preceded by small numbers and quicker to detect right-side targets when they are preceded by large numbers—has been used as evidence for embodied number representations and to support strong claims about the link between number and space (e.g., a mental number line). We attempted to replicate Experiment 2 of Fischer et al. by collecting data from 1,105 participants at 17 labs. Across all 1,105 participants and four interstimulus-interval conditions, the proportion of times the effect we observed was positive (i.e., directionally consistent with the original effect) was .50. Further, the effects we observed both within and across labs were minuscule and incompatible with those observed by Fischer et al. Given this, we conclude that we failed to replicate the effect reported by Fischer et al. In addition, our analysis of several participant-level moderators (finger-counting habits, reading and writing direction, handedness, and mathematics fluency and mathematics anxiety) revealed no substantial moderating effects. Our results indicate that the Att-SNARC effect cannot be used as evidence to support strong claims about the link between number and space.

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Singh, Pawan Kishor, Anjali Kapoor, Richa Madan Lomash, Kamal Kumar, Sukrut C. Kamerkar, Thomas J. Pucadyil et Amitabha Mukhopadhyay. « Salmonella SipA mimics a cognate SNARE for host Syntaxin8 to promote fusion with early endosomes ». Journal of Cell Biology 217, n^o 12 (11 octobre 2018) : 4199–214. http://dx.doi.org/10.1083/jcb.201802155.

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SipA is a major effector of Salmonella, which causes gastroenteritis and enteric fever. Caspase-3 cleaves SipA into two domains: the C-terminal domain regulates actin polymerization, whereas the function of the N terminus is unknown. We show that the cleaved SipA N terminus binds and recruits host Syntaxin8 (Syn8) to Salmonella-containing vacuoles (SCVs). The SipA N terminus contains a SNARE motif with a conserved arginine residue like mammalian R-SNAREs. SipAR204Q and SipA1–435R204Q do not bind Syn8, demonstrating that SipA mimics a cognate R-SNARE for Syn8. Consequently, Salmonella lacking SipA or that express the SipA1–435R204Q SNARE mutant are unable to recruit Syn8 to SCVs. Finally, we show that SipA mimicking an R-SNARE recruits Syn8, Syn13, and Syn7 to the SCV and promotes its fusion with early endosomes to potentially arrest its maturation. Our results reveal that SipA functionally substitutes endogenous SNAREs in order to hijack the host trafficking pathway and promote Salmonella survival.

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Hickey, Christopher M., et William Wickner. « HOPS Initiates Vacuole Docking by Tethering Membranes before trans-SNARE Complex Assembly ». Molecular Biology of the Cell 21, n^o 13 (juillet 2010) : 2297–305. http://dx.doi.org/10.1091/mbc.e10-01-0044.

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Vacuole homotypic fusion has been reconstituted with all purified components: vacuolar lipids, four soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) proteins, Sec17p, Sec18p, the Rab Ypt7p, and the hexameric homotypic fusion and vacuole protein sorting complex (HOPS). HOPS is a Rab-effector with direct affinity for SNAREs (presumably via its Sec1-Munc18 homologous subunit Vps33p) and for certain vacuolar lipids. Each of these pure vacuolar proteins was required for optimal proteoliposome clustering, raising the question of which was most directly involved. We now present model subreactions of clustering and fusion that reveal that HOPS is the direct agent of tethering. The Rab and vacuole lipids contribute to tethering by supporting the membrane association of HOPS. HOPS indirectly facilitates trans-SNARE complex formation by tethering membranes, because the synthetic liposome tethering factor polyethylene glycol can also stimulate trans-SNARE complex formation and fusion. SNAREs further stabilize the associations of HOPS-tethered membranes. HOPS then protects newly formed trans-SNARE complexes from disassembly by Sec17p/Sec18p.

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Wiederkehr, Andreas, Johan-Owen De Craene, Susan Ferro-Novick et Peter Novick. « Functional specialization within a vesicle tethering complex ». Journal of Cell Biology 167, n^o 5 (6 décembre 2004) : 875–87. http://dx.doi.org/10.1083/jcb.200408001.

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The exocyst is an octameric protein complex required to tether secretory vesicles to exocytic sites and to retain ER tubules at the apical tip of budded cells. Unlike the other five exocyst genes, SEC3, SEC5, and EXO70 are not essential for growth or secretion when either the upstream activator rab, Sec4p, or the downstream SNARE-binding component, Sec1p, are overproduced. Analysis of the suppressed sec3Δ, sec5Δ, and exo70Δ strains demonstrates that the corresponding proteins confer differential effects on vesicle targeting and ER inheritance. Sec3p and Sec5p are more critical than Exo70p for ER inheritance. Although nonessential under these conditions, Sec3p, Sec5p, and Exo70p are still important for tethering, as in their absence the exocyst is only partially assembled. Sec1p overproduction results in increased SNARE complex levels, indicating a role in assembly or stabilization of SNARE complexes. Furthermore, a fraction of Sec1p can be coprecipitated with the exoycst. Our results suggest that Sec1p couples exocyst-mediated vesicle tethering with SNARE-mediated docking and fusion.

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Lynch, Kara L., Roy R. L. Gerona, Dana M. Kielar, Sascha Martens, Harvey T. McMahon et Thomas F. J. Martin. « Synaptotagmin-1 Utilizes Membrane Bending and SNARE Binding to Drive Fusion Pore Expansion ». Molecular Biology of the Cell 19, n^o 12 (décembre 2008) : 5093–103. http://dx.doi.org/10.1091/mbc.e08-03-0235.

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In regulated vesicle exocytosis, SNARE protein complexes drive membrane fusion to connect the vesicle lumen with the extracellular space. The triggering of fusion pore formation by Ca2+ is mediated by specific isoforms of synaptotagmin (Syt), which employ both SNARE complex and membrane binding. Ca2+ also promotes fusion pore expansion and Syts have been implicated in this process but the mechanisms involved are unclear. We determined the role of Ca2+-dependent Syt-effector interactions in fusion pore expansion by expressing Syt-1 mutants selectively altered in Ca2+-dependent SNARE binding or in Ca2+-dependent membrane insertion in PC12 cells that lack vesicle Syts. The release of different-sized fluorescent peptide-EGFP vesicle cargo or the vesicle capture of different-sized external fluorescent probes was used to assess the extent of fusion pore dilation. We found that PC12 cells expressing partial loss-of-function Syt-1 mutants impaired in Ca2+-dependent SNARE binding exhibited reduced fusion pore opening probabilities and reduced fusion pore expansion. Cells with gain-of-function Syt-1 mutants for Ca2+-dependent membrane insertion exhibited normal fusion pore opening probabilities but the fusion pores dilated extensively. The results indicate that Syt-1 uses both Ca2+-dependent membrane insertion and SNARE binding to drive fusion pore expansion.

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Themelin, D., P. Duchatelet, W. Boudaka et V. Lamy. « Endoscopic resection of an endobronchial hypernephroma metastasis using a polypectomy snare ». European Respiratory Journal 3, n^o 6 (1 juin 1990) : 732–33. http://dx.doi.org/10.1183/09031936.93.03060732.

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A 69 yr old male patient developed an acute respiratory distress. The emergency bronchoscopic examination showed a polypoid tumour obstructing the left main bronchus. A snare used for colorectal polypectomy was introduced through the bronchofibrescope to remove the tumour. The patient then dramatically improved. No side effects were observed. Histopathological examination showed metastasis from a hypernephroma. This simple technique is useful for bronchial deobstruction, when the tumour is accessible with a snare.

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Guida, Alessandro, et Guillermo Campitelli. « Explaining the SPoARC and SNARC effects with knowledge structures : An expertise account ». Psychonomic Bulletin & ; Review 26, n^o 2 (18 mars 2019) : 434–51. http://dx.doi.org/10.3758/s13423-019-01582-0.

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Câmara, Guilherme Schmidt, Kristian Nymoen, Olivier Lartillot et Anne Danielsen. « Timing Is Everything…Or Is It ? Effects of Instructed Timing Style, Reference, and Pattern on Drum Kit Sound in Groove-Based Performance ». Music Perception 38, n^o 1 (septembre 2020) : 1–26. http://dx.doi.org/10.1525/mp.2020.38.1.1.

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This study reports on an experiment that tested whether drummers systematically manipulated not only onset but also duration and/or intensity of strokes in order to achieve different timing styles. Twenty-two professional drummers performed two patterns (a simple “back-beat” and a complex variation) on a drum kit (hi-hat, snare, kick) in three different timing styles (laid-back, pushed, on-beat), in tandem with two timing references (metronome and instrumental backing track). As expected, onset location corresponded to the instructed timing styles for all instruments. The instrumental reference led to more pronounced timing profiles than the metronome (pushed strokes earlier, laid-back strokes later). Also, overall the metronome reference led to earlier mean onsets than the instrumental reference, possibly related to the “negative mean asynchrony” phenomenon. Regarding sound, results revealed systematic differences across participants in the duration (snare) and intensity (snare and hi-hat) of strokes played using the different timing styles. Pattern also had an impact: drummers generally played the rhythmically more complex pattern 2 louder than the simpler pattern 1 (snare and kick). Overall, our results lend further evidence to the hypothesis that both temporal and sound-related features contribute to the indication of the timing of a rhythmic event in groove-based performance.

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Kama, Rachel, Vydehi Kanneganti, Christian Ungermann et Jeffrey E. Gerst. « The yeast Batten disease orthologue Btn1 controls endosome–Golgi retrograde transport via SNARE assembly ». Journal of Cell Biology 195, n^o 2 (10 octobre 2011) : 203–15. http://dx.doi.org/10.1083/jcb.201102115.

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The human Batten disease gene CLN3 and yeast orthologue BTN1 encode proteins of unclear function. We show that the loss of BTN1 phenocopies that of BTN2, which encodes a retromer accessory protein involved in the retrieval of specific cargo from late endosomes (LEs) to the Golgi. However, Btn1 localizes to Golgi and regulates soluble N-ethyl-maleimide sensitive fusion protein attachment protein receptor (SNARE) function to control retrograde transport. Specifically, BTN1 overexpression and deletion have opposing effects on phosphorylation of the Sed5 target membrane SNARE, on Golgi SNARE assembly, and on Golgi integrity. Although Btn1 does not interact physically with SNAREs, it regulates Sed5 phosphorylation by modulating Yck3, a palmitoylated endosomal kinase. This may involve modification of the Yck3 lipid anchor, as substitution with a transmembrane domain suppresses the deletion of BTN1 and restores trafficking. Correspondingly, deletion of YCK3 mimics that of BTN1 or BTN2 with respect to LE–Golgi retrieval. Thus, Btn1 controls retrograde sorting by regulating SNARE phosphorylation and assembly, a process that may be adversely affected in Batten Disease patients.

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Weber-Boyvat, Marion, Nina Aro, Konstantin G. Chernov, Tuula Nyman et Jussi Jäntti. « Sec1p and Mso1p C-terminal tails cooperate with the SNAREs and Sec4p in polarized exocytosis ». Molecular Biology of the Cell 22, n^o 2 (15 janvier 2011) : 230–44. http://dx.doi.org/10.1091/mbc.e10-07-0592.

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The Sec1/Munc18 protein family members perform an essential, albeit poorly understood, function in association with soluble n-ethylmaleimide sensitive factor adaptor protein receptor (SNARE) complexes in membrane fusion. The Saccharomyces cerevisiae Sec1p has a C-terminal tail that is missing in its mammalian homologues. Here we show that deletion of the Sec1p tail (amino acids 658–724) renders cells temperature sensitive for growth, reduces sporulation efficiency, causes a secretion defect, and abolishes Sec1p-SNARE component coimmunoprecipitation. The results show that the Sec1p tail binds preferentially ternary Sso1p-Sec9p-Snc2p complexes and it enhances ternary SNARE complex formation in vitro. The bimolecular fluorescence complementation (BiFC) assay results suggest that, in the SNARE-deficient sso2–1 Δsso1 cells, Mso1p, a Sec1p binding protein, helps to target Sec1p(1–657) lacking the C-terminal tail to the sites of secretion. The results suggest that the Mso1p C terminus is important for Sec1p(1–657) targeting. We show that, in addition to Sec1p, Mso1p can bind the Rab-GTPase Sec4p in vitro. The BiFC results suggest that Mso1p acts in close association with Sec4p on intracellular membranes in the bud. This association depends on the Sec4p guanine nucleotide exchange factor Sec2p. Our results reveal a novel binding mode between the Sec1p C-terminal tail and the SNARE complex, and suggest a role for Mso1p as an effector of Sec4p.

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Cipora, Krzysztof, Mojtaba Soltanlou, Ulf-Dietrich Reips et Hans-Christoph Nuerk. « The SNARC and MARC effects measured online : Large-scale assessment methods in flexible cognitive effects ». Behavior Research Methods 51, n^o 4 (25 février 2019) : 1676–92. http://dx.doi.org/10.3758/s13428-019-01213-5.

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Ha, Si Young, Ji Young Jung, Dong Hwan Lee et Jae-Kyung Yang. « Anti-allergic and anti-inflammatory effects of hydrosol extracted from Zanthoxylum schinifolium branch ». BioResources 16, n^o 3 (1 juillet 2021) : 5721–32. http://dx.doi.org/10.15376/biores.16.3.5721-5732.

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Zanthoxylum schinifolium Sieb. et Zucc. (syn. Fagara schinifolia Engler) was studied for its potential anti-inflammatory properties. The hydrosol extract prepared from the Z. schinifolium branch was analyzed by gas chromatography/mass spectrometry. Here, five main chemical components were identified in the hydrosol of the branches of this shrub. The main chemical compounds in the branch inhibited both an Immunoglobulin E (IgE)-antigen complex and a dinitrophenyl-bovine serum albumin (DNP-BSA)-induced β-hexosaminidase release in a dose-dependent manner in RBL-2H3 mast cells, and at the tested concentrations did not show cytotoxicity to RBL-2H3 cells. Moreover, hydrosol obtained from the branch substantially inhibited a lipopolysaccharide (LPS) induced overproduction of intracellular active oxygen (ROS) and nitric oxide (NO). Consistently, the soluble N-ethylmaleimide-sensitive factor-attachment protein receptor (SNARE) proteins of SNAP23, syntaxin4, VAMP7, and VAMP8 were remarkably decreased through hydrosol treatment. Hydrosol suppressed the activation of SNARE proteins in DNP-BSA-stimulated RBL-2H3 cells and inhibited ROS and NO in LPS-stimulated RAW264.7 cells. Camphor and estragole are the main chemical components of hydrosol and downregulate the LPS-induced phosphorylation of the SNARE proteins. The hydrosol obtained from the branch of Z. schinifolium has therapeutic benefits for allergic inflammatory diseases.

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Pérez-Legaspi, IA, R. Rico-Martínez et JL Quintanar. « Reduced expression of exocytotic proteins caused by anti-cholinesterase pesticides in Brachionus calyciflorus (Rotifera : Monogononta) ». Brazilian Journal of Biology 75, n^o 3 (25 août 2015) : 759–65. http://dx.doi.org/10.1590/1519-6984.01614.

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AbstractThe organophosphate and carbamate pesticides methyl-parathion and carbaryl have a common action mechanism: they inhibit acetylcholinesterase enzyme by blocking the transmission of nerve impulses. However, they can alter the expression of exocytotic membrane proteins (SNARE), by modifying release of neurotransmitters and other substances. This study evaluated the adverse effects of the pesticides methyl-parathion and carbaryl on expression of SNARE proteins: Syntaxin-1, Syntaxin-4 and SNAP-23 in freshwater rotifer Brachionus calyciflorus. Protein expression of these three proteins was analyzed before and after exposure to these two pesticides by Western Blot. The expression of Syntaxin-1, Syntaxin-4 and SNAP-23 proteins in B. calyciflorussignificantly decreases with increasing concentration of either pesticides. This suggests that organophosphates and carbamates have adverse effects on expression of membrane proteins of exocytosis by altering the recognition, docking and fusion of presynaptic and vesicular membranes involved in exocytosis of neurotransmitters. Our results demonstrate that the neurotoxic effect of anticholinesterase pesticides influences the interaction of syntaxins and SNAP-25 and the proper assembly of the SNARE complex.

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Yang, Yoosoo, Paul Heo, Byoungjae Kong, Jun-Bum Park, Young-Hun Jung, Jonghyeok Shin, Cherlhyun Jeong et Dae-Hyuk Kweon. « Dynamic light scattering analysis of SNARE-driven membrane fusion and the effects of SNARE-binding flavonoids ». Biochemical and Biophysical Research Communications 465, n^o 4 (octobre 2015) : 864–70. http://dx.doi.org/10.1016/j.bbrc.2015.08.111.

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Hayes, Rebecca A., et Caleb T. Carr. « Snark Happens : Effects of Schadenfreude on Brand Attitudes ». Journal of Current Issues & ; Research in Advertising 41, n^o 2 (1 mai 2020) : 243–56. http://dx.doi.org/10.1080/10641734.2020.1738290.

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Cheshire, Matthew, Jake Drysdale, Sean Enderby, Maciej Tomczak et Jason Hockman. « Deep Audio Effects for Snare Drum Recording Transformations ». Journal of the Audio Engineering Society 70, n^o 9 (2 novembre 2022) : 742–52. http://dx.doi.org/10.17743/jaes.2022.0041.

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