Rational Design of Electrochemiluminescent Devices

ConspectusElectrochemiluminescence (ECL) is a light-emitting process which combines the intriguing merits of both electrochemical and chemiluminescent methods. It is an extensively used method especially in clinical analysis and biological research due to its high sensitivity, wide dynamic range, and good reliability. ECL devices are critical for the development and applications of ECL. Much effort has been expended to improve the sensitivity, portability, affordability, and throughput of new ECL devices, which allow ECL to adapt broad usage scenarios.In this Account, we summarize our efforts on the recent development of ECL devices including new electrodes, ECL devices based on a wireless power transfer (WPT) technique, and novel bipolar electrochemistry. As the essential components in the ECL devices, electrodes play an important role in ECL detection. We have significantly improved the sensitivity of luminol ECL detection of H2O2 by using a stainless steel electrode. By using semiconductor materials (e.g., silicon and BiVO4), we have exploited photoinduced ECL to generate intense emission at much lower potentials upon illumination. For convenience, portability, and disposability, ECL devices based on cheap WPT devices have been designed. A small diode has been employed to rectify alternating current into direct current to dramatically enhance ECL intensity, enabling sensitive ECL detection using a smart phone as a detector. Finally, we have developed several ECL devices based on bipolar electrochemistry in view of the convenience of multiplex ECL sensing using a bipolar electrode (BPE). On the basis of the wireless feature of BPE, we have employed movable BPEs (e.g., BPE swimmers and magnetic rotating BPE) for deep exploration of the motional and ECL properties of dynamic BPE systems. To make full use of the ECL solution, we have dispersed numerous micro-/nano-BPEs in solution to produce intense 3D ECL in the entire solution, instead of 2D ECL in conventional ECL devices. In addition, the interference of ECL noise from driving electrodes was minimized by introducing the stainless steel with a passivation layer as the driving electrode. To eliminate the need for the fabrication of electrode arrays and the interference from the driving electrode and to decrease the applied voltage, we develop a new-type BPE device consisting of a single-electrode electrochemical system (SEES) based on a resistance-induced potential difference. The SEES is fabricated easily by attaching a multiperforated plate to a single film electrode. It enables the simultaneous detection of many samples and analytes using only a single film electrode (e.g., screen-printed electrode) instead of electrode arrays. It is of great potential in clinical analysis especially for multiple-biomarker detection, drug screening, and biological studies. Looking forward, we believe that more ECL devices and related ECL materials and detection methods will be developed for a wide range of applications, such as in vitro diagnosis, point-of-care testing, high-throughput analysis, drug screening, biological study, and mechanism investigation.Conversion lumineuse par électrochimiluminescence photoinduit

Sensory analysis of concord wines after chemical removal of methyl anthranlate results in higher acceptability, and less "foxy" aroma

A major feature of wine made from Concord grape is the very intense grape flavor referred to as “Foxy” which is not desirable in high quality wine, and limits the utility of this cold-resistant native grape. After using a chemical deodorization process to remove Methyl Anthranilate which causes this flavor, we report results of descriptive and affective sensory studies on wine made with concord juice with and without deodorization, as well as comparing it to an inexpensive wine made from non-concord grapes, and a blended sample. The goal of the study was to assess whether chemical removal of Foxy aroma would result in a perceptible change in sensory properties, and further in acceptability of the wine. The results from both descriptive and consumer sensory testing showed that Foxy flavor was significantly decreased in the deodorized wine, and that liking for deodorized samples was significantly higher than non-deodorized, despite most other sensory aspects of the wine remaining unchanged. We conclude that the deodorization process may allow wine producers to make more acceptable wine using blending of wine from such inexpensive native grapes

Les protéines TET, Nouveaux Régulateurs des Récepteurs Nucléaires

Thyroid hormone (T3) controls both developmental and physiological processes. Its nuclear receptors, thyroid hormone receptors (TRs), are members of the nuclear hormone receptor family which act as ligand-dependent transcription factors. DNA methylation at the fifth position of cytosine is an important epigenetic modification that affects chromatin structure and gene expression. Recent studies have established a critical function of the Ten-eleven translocation (TET) family proteins in regulating DNA methylation dynamics by converting 5-methyl-cytosine (5mC) into 5-hydroxymethylcytosine (5hmC). Studies demonstrated that TETs proteins (including TET1, TET2 and TET3) possess catalytic activity dependent and independent transcriptional regulatory functions. Our study identified TET3 as a new TR interacting protein. The AF2 domain of TR and the catalytic domain and CXXC domain of TET3 are responsible for their interaction. This interaction allows the stabilization of chromatin bound TR, resulting in a potentiation of its transcriptional activity. The modulation effect of TET3 on TR presented here is independent of its hydroxylase activity. Thus this study evidences a new mode of action for TET3 as a non-classical regulator of TR, modulating its stability and access to chromatin rather that its intrinsic transcriptional activity. Mutations in TR cause the RTH symptom which severity varies with the particular mutation. The differential ability of different TRα mutants, relevant for the human RTHα disease, to interact with TET3 might explain their differential dominant negative activity. The regulatory function of TET3 might be more general towards the nuclear receptor transcriptional factors since different members of the superfamily present the same interaction with TET3, such as AR (androgen receptor), ERR (Estrogen-related receptor) and RAR (retinoic acid receptor). The interaction between TET3 and RAR involves the DNA binding domain of RAR. The functional relevance of TET3/RAR interaction was further studied in ES cells. Combined deficiency of all three TETs led to depletion of 5hmC and deregulation of genes involved in ES differentiation. Among the deregulated genes, a subset of RA response genes was identified, suggesting that RARs (retinoic acid receptors) and TETs might work together to regulate ES cell differentiation. Further dissection revealed that TET proteins may have a role in facilitating RAR recruitment to the promoter regions of these RAR target genes. Moreover, our results indicated a potential role of the hydroxylase activity of TET proteins in modulating RAR transcriptional activity. Altogether, our work identified TET proteins as new regulators of NR (Nuclear Receptors). The exact mechanisms involved need to be further studied.L'hormone thyroïdienne (T3) contrôle à la fois les processus développementaux et physiologiques. Elle agit via les récepteurs de l'hormone thyroïdienne (TR), membres de la famille des récepteurs hormonaux nucléaires. Ils agissent comme des facteurs de transcription dépendants du ligand. La méthylation de l'ADN en position 5 de la cytosine est une modification épigénétique importante qui affecte la structure de la chromatine et l'expression des gènes. Des études récentes ont établi un rôle important des protéines de la famille TET (Ten-eleven translocation) dans la régulation de la dynamique de la méthylation de l'ADN. Elles convertissent la 5-méthyl-cytosine (5mC) en 5-hydroxyméthylcytosine (5hmC). D’autres études ont démontré que les protéines TET (TET1, TET2 et TET3) possèdent des fonctions de régulation transcriptionnelle dépendantes et indépendantes de leur activité catalytique. Notre étude a identifié TET3 comme une nouvelle protéine interagissant avec TR. Le domaine AF2 de TR ainsi que le domaine catalytique et le domaine CXXC de TET3 sont responsables de cette interaction. Celle-ci permet la stabilisation de TR lié à la chromatine, entraînant une potentialisation de son activité transcriptionnelle. L'effet de modulation de TET3 sur TR présenté ici est indépendant de son activité hydroxylase de TET3. Ainsi, cette étude met en évidence un nouveau mode d'action de TET3 en tant que régulateur non classique de TR, modulant sa stabilité et son accès à la chromatine plutôt que son activité de transcription intrinsèque. Des mutations du gène codant pour TRα provoquent le symptôme RTHα dont la gravité varie en fonction de la mutation. Les différentes capacités d’interaction des mutants TRα, pertinents pour la maladie de RTHα humaine, avec TET3 pourraient expliquer les différences d’effet dominant négatif. La fonction de régulation de TET3 pourrait s’appliquer plus généralement aux facteurs de transcription des récepteurs nucléaires, car différents membres de la superfamille des récepteurs nucléaires présentent la même interaction avec TET3, tels que AR (récepteur des androgènes), ERR (récepteur des œstrogènes) et RAR (récepteur de l'acide rétinoïque). L'interaction entre TET3 et RAR implique le domaine de liaison ADN de RAR. La pertinence fonctionnelle de l'interaction TET3 / RAR a été étudiée plus en détail dans les cellules souches embryonnaire (cellules ES). L’absence combinée des trois TET a entraîné la diminution de 5hmC et la dérégulation des gènes impliqués dans la différenciation des cellules ES. Parmi les gènes dérégulés, nous avons identifié un sous-ensemble de gènes cibles de l’acide rétinoïque, suggérant que les RAR (récepteurs d'acide rétinoïque) et les TET pourraient travailler ensemble pour réguler la différenciation des cellules ES. Une étude supplémentaire a révélé que les protéines TET peuvent jouer un rôle dans la facilitation du recrutement de RAR aux régions promotrices de ses gènes cibles. En outre, nos résultats montrent un rôle potentiel de l'activité hydroxylase des protéines TET dans la modulation de l'activité transcriptionnelle des RAR. En conclusion, notre travail a identifié les protéines TET comme nouveaux régulateurs des récepteurs nucléaires. Les mécanismes exacts impliqués doivent être étudiés plus avant

Shaping the size of a neuronal lineage: the role of Imp and Syp RBPs in the precise elimination of neurons by apoptosis

SUMMARY Neuronal stem cells produce a finite and stereotyped number of neuronal progenies. This process must be finely regulated during development and adult stages to ensure proper brain function. In Drosophila, stem cells, called Neuroblasts, produce an invariant number of neurons. Two RNA binding proteins, Imp and Syp, play a central role in controlling the speed of division and the end of the proliferative phase of individual NBs, two parameters that influences the final number of neurons produced. Here, we have discovered a novel function for Imp and Syp, where both RBPs also shape the number of neurons produced by a stem cell by controlling program cell death (PCD) in immature neurons. By studying a neuroblast lineage, called Lin A/15, which produces motoneurons (MNs) and glia, we have demonstrated that Lin A/15 stem cell spends 40% of its time producing immature MNs which are eliminated by apoptosis. We have revealed that only the first born MNs (Imp +) survive while the last born MNs (Imp-Syp+) are eliminated by apoptosis. Both RBPs play a central role in neuronal survival, Imp promotes neuronal survival while Syp promotes cell death in immature motoneurons. Interestingly their opposite temporal gradient in Lin A/15 stem cell also determines the end of Lin A/15 stem cell neurogenesis by PCD. Both RNA binding proteins are conserved in vertebrates and seem to play a central role in the number of neurons produce during development. The Drosophila model and its genetic tools offer a unique chance to decipher their function in neural stem cell versus immature neurons

A simple smiFISH pipeline to quantify mRNA at the single-cell level in 3D

Summary: Techniques allowing the precise quantification of mRNA at the cellular level are essential for understanding biological processes. Here, we present a semi-automated smiFISH (single-molecule inexpensive FISH) pipeline enabling quantification of mRNA in a small number of cells (∼40) in fixed whole mount tissue. We describe steps for sample preparation, hybridization, image acquisition, cell segmentation, and mRNA quantification. Although the protocol was developed in Drosophila, it can be optimized for use in other organisms.For complete details on the use and execution of this protocol, please refer to Guan et al.1 : Publisher’s note: Undertaking any experimental protocol requires adherence to local institutional guidelines for laboratory safety and ethics

Study on Laser Parameter Measurement System Based on Cone-Arranged Fibers and CCD Camera

This paper proposes a new laser parameter measuring method based on cone-arranged fibers to further improve the measurable spot size, allowable incident angle range, and spatial sampling resolution. This method takes a conical array composed of flexible fibers to sample and shrink the cross-section spot of the laser beam, facilitating low-distortion shooting with a charge-coupled diode (CCD) camera, and adopts homogenized processing and algorithm analysis to correct the spot. This method is experimentally proven to achieve high-accuracy measurements with a decimeter-level spot-receiving surface, millimeter-level resolution, and high tolerance in order to incite skew angle. Comparing the measured spot under normal incidence with the real one, the root mean square error (RMSE) of their power in the bucket (PIB) curves is less than 1%. When the incident angle change is between −8° and 8°, the RMSE is less than 2% and the measurement error of total power is less than 5% based on the premise that the fiber’s numerical aperture (NA) is 0.22. The possibility of further optimizing the measurement method by changing the fiber parameters and array design is also reported

Methylcytosine dioxygenase TET3 interacts with thyroid hormone nuclear receptors and stabilizes their association to chromatin

International audienceThyroid hormone receptors (TRs) are members of the nuclear hormone receptor superfamily that act as ligand-dependent transcription factors. Here we identified the ten-eleven translocation protein 3 (TET3) as a TR interacting protein increasing cell sensitivity to T3. The interaction between TET3 and TRs is independent of TET3 catalytic activity and specifically allows the stabilization of TRs on chromatin. We provide evidence that TET3 is required for TR stability, efficient binding of target genes, and transcriptional activation. Interestingly, the differential ability of different TRα1 mutants to interact with TET3 might explain their differential dominant activity in patients carrying TR germline mutations. So this study evidences a mode of action for TET3 as a nonclassical coregulator of TRs, modulating its stability and access to chromatin, rather than its intrinsic transcriptional activity. This regulatory function might be more general toward nuclear receptors. Indeed, TET3 interacts with different members of the superfamily and also enhances their association to chromatin

The role of Imp and Syp RBPs in precise neuronal elimination by apoptosis through the regulation of TFs

Neuronal stem cells generate a limited and consistent number of neuronal progenies, each possessing distinct morphologies and functions. These two parameters, involving the precise production of neurons with distinct identities, must be meticulously regulated throughout development to ensure optimal brain function. In our study, we focused on a neuroblast lineage in Drosophila known as Lin A/15, which gives rise to motoneurons (MNs) and glia. Interestingly, Lin A/15 neuroblast dedicates 40% of its time to producing immature MNs that are subsequently eliminated through apoptosis. Two RNA-binding proteins, Imp and Syp, play crucial roles in this process of neuronal elimination. We found that Imp+ MNs survive, while Imp-, Syp+ MNs undergo apoptosis. Our results indicate that Imp promotes survival, whereas Syp promotes cell death in immature MNs. Furthermore, our investigations revealed that late-born motoneurons face elimination due to their failure to express a functional code of transcription factors (mTFs) that control their morphological fate Late-born MNs possess a unique and distinct set of TFs compared to early-born MNs. By manipulating the expression of Imp and Syp in late-born motoneurons, we observed a shift in the TF code of late MNs towards that of early-born MNs, resulting in their survival. Additionally, introducing the TF code of early MNs into late-born MNs also promoted their survival. These findings demonstrate that the differential expression of Imp and Syp in immature MNs establishes a connection between generating a precise number of MNs and producing MNs with distinct identities through the regulation of mTFs. Importantly, both Imp and Syp are conserved in vertebrates, suggesting that they play a central role in determining the number of neurons produced during development. The Drosophila model, along with its genetic tools, provides a unique opportunity to further explore and decipher the functions of these RNA-binding proteins in neural stem cells versus immature neurons. The insights gained from these studies could shed light on the broader mechanisms of neurogenesis and neuronal identity determination in more complex organisms

The role of Imp and Syp RBPs in precise neuronal elimination by apoptosis through the regulation of TFs

Neuronal stem cells generate a limited and consistent number of neuronal progenies, each possessing distinct morphologies and functions. These two parameters, involving the precise production of neurons with distinct identities, must be meticulously regulated throughout development to ensure optimal brain function. In our study, we focused on a neuroblast lineage in Drosophila known as Lin A/15, which gives rise to motoneurons (MNs) and glia. Interestingly, Lin A/15 neuroblast dedicates 40% of its time to producing immature MNs that are subsequently eliminated through apoptosis. Two RNA-binding proteins, Imp and Syp, play crucial roles in this process of neuronal elimination. We found that Imp+ MNs survive, while Imp-, Syp+ MNs undergo apoptosis. Our results indicate that Imp promotes survival, whereas Syp promotes cell death in immature MNs. Furthermore, our investigations revealed that late-born motoneurons face elimination due to their failure to express a functional code of transcription factors (mTFs) that control their morphological fate Late-born MNs possess a unique and distinct set of TFs compared to early-born MNs. By manipulating the expression of Imp and Syp in late-born motoneurons, we observed a shift in the TF code of late MNs towards that of early-born MNs, resulting in their survival. Additionally, introducing the TF code of early MNs into late-born MNs also promoted their survival. These findings demonstrate that the differential expression of Imp and Syp in immature MNs establishes a connection between generating a precise number of MNs and producing MNs with distinct identities through the regulation of mTFs. Importantly, both Imp and Syp are conserved in vertebrates, suggesting that they play a central role in determining the number of neurons produced during development. The Drosophila model, along with its genetic tools, provides a unique opportunity to further explore and decipher the functions of these RNA-binding proteins in neural stem cells versus immature neurons. The insights gained from these studies could shed light on the broader mechanisms of neurogenesis and neuronal identity determination in more complex organisms

The role of Imp and Syp RBPs in precise neuronal elimination by apoptosis through the regulation of TFs

Neuronal stem cells generate a limited and consistent number of neuronal progenies, each possessing distinct morphologies and functions. These two parameters, involving the precise production of neurons with distinct identities, must be meticulously regulated throughout development to ensure optimal brain function. In our study, we focused on a neuroblast lineage in Drosophila known as Lin A/15, which gives rise to motoneurons (MNs) and glia. Interestingly, Lin A/15 neuroblast dedicates 40% of its time to producing immature MNs that are subsequently eliminated through apoptosis. Two RNA-binding proteins, Imp and Syp, play crucial roles in this process of neuronal elimination. We found that Imp+ MNs survive, while Imp-, Syp+ MNs undergo apoptosis. Our results indicate that Imp promotes survival, whereas Syp promotes cell death in immature MNs. Furthermore, our investigations revealed that late-born motoneurons face elimination due to their failure to express a functional code of transcription factors (mTFs) that control their morphological fate Late-born MNs possess a unique and distinct set of TFs compared to early-born MNs. By manipulating the expression of Imp and Syp in late-born motoneurons, we observed a shift in the TF code of late MNs towards that of early-born MNs, resulting in their survival. Additionally, introducing the TF code of early MNs into late-born MNs also promoted their survival. These findings demonstrate that the differential expression of Imp and Syp in immature MNs establishes a connection between generating a precise number of MNs and producing MNs with distinct identities through the regulation of mTFs. Importantly, both Imp and Syp are conserved in vertebrates, suggesting that they play a central role in determining the number of neurons produced during development. The Drosophila model, along with its genetic tools, provides a unique opportunity to further explore and decipher the functions of these RNA-binding proteins in neural stem cells versus immature neurons. The insights gained from these studies could shed light on the broader mechanisms of neurogenesis and neuronal identity determination in more complex organisms