Reserve Pool Research Articles

Chaotic laser time series prediction based on an improved logistic mapping algorithm echo state network

Chaos synchronization plays vital functions in the fields of optical chaos secure communication. The synchronization performance can be significantly degraded by parameter mismatches between the chaotic transmitter and receiver. In this paper, the Deep-Logistical Mapping Echo State Network (D-LMESN) is proposed to enhance the performance of chaos synchronization. The network is upgraded by using an improved logical mapping algorithm and a deep reserve pool structure with phase space reconstruction. Results show that D-LMESN exhibits better performance in the prediction of chaotic time series, thanks to the adaptive parameter adjustment, which increases the ability to capture the dynamic characteristics of complex systems. Compared with ESN, the mean square error of this model is reduced by 55% and 72%, respectively, in chaotic laser simulation and actual data experiments. This provides a new possibility, to our knowledge, for the development of chaotic secure communication.

Dissecting dormancy and quiescence in hematopoietic stem cells

Quiescence is a fundamental state of adult hematopoietic stem cells (HSCs) characterized by their residence in the G0 phase of the cell cycle. Despite being quiescent, HSCs retain their capacities for self-renewal and multipotency, enabling them to produce all blood lineages. Recent discoveries have shown that HSCs can dive into an even deeper state of quiescence with a very low division rate in steady-state conditions, known as dormancy. Dormant HSCs (dHSCs) have the most superior stem cell properties among HSCs, placing them at the top of the hematopoietic hierarchy. In this review, we argue that quiescence and dormancy are not synonyms in the context of HSCs. Specifically, dHSCs constitute a unique reserve pool of HSCs, mobilized only under stress conditions to protect the HSC compartment throughout life. While HSC quiescence is well-studied, the molecular features of HSC dormancy remain less well-defined. We will discuss the available methods for dHSC isolation and summarize the latest findings on the roles of niche factors, transcription factors, chromatin regulators, and cell cycle-related proteins in maintaining HSC dormancy. Additionally, we will explore whether insights from the quiescent HSC research can be applied to dHSCs. Lastly, we will assess the therapeutic potential of utilizing or targeting dHSCs to improve stem cell transplantation outcomes and treat hematological diseases, opening new avenues for research and clinical applications in regenerative medicine and oncology.

DMXL2 Is Required for Endocytosis and Recycling of Synaptic Vesicles in Auditory Hair Cells.

Ribbon synapses of inner hair cells (IHCs) are uniquely designed for ultrafast and indefatigable neurotransmission of the sound. The molecular machinery ensuring the efficient, compensatory recycling of the synaptic vesicles (SVs), however, remains elusive. This study showed that hair cell knock-out of murine Dmxl2, whose human homolog is responsible for nonsyndromic sensorineural hearing loss DFNA71, resulted in auditory synaptopathy by impairing synaptic endocytosis and recycling. The mutant mice in the C57BL/6J background of either sex had mild hearing loss with severely diminished wave I amplitude of the auditory brainstem response. Membrane capacitance measurements of the IHCs revealed deficiency in sustained synaptic exocytosis and endocytic membrane retrieval. Consistent with the electrophysiological findings, 3D electron microscopy reconstruction showed reduced reserve pool of SVs and endocytic compartments, while the membrane-proximal and ribbon-associated vesicles remain intact. Our results propose an important role of DMXL2 in hair cell endocytosis and recycling of the SVs.

Algorithms of Cross-Domain Redundancy Management for Resilient of Dual-Priority Critical Communication Systems

The paper presents models for managing cross-domain redundancy to enhance the reliability of two priority communication channels within critical infrastructure systems. Employing Markov chain models, the paper analyzes the impact of two distinct redundancy management strategies: a unified reserve pool and a separate pool approach with cross-domain resource sharing. The study introduces reliability improvement factors to quantify system performance, exploring their dependency on the number of additional redundant elements, their inherent reliability, and the chosen strategy for managing cross-domain redundancy. An air traffic control system serves as a case study of the application of the proposed management algorithms. Results indicate that the integration of resources from different priority domains significantly improves communication reliability. The findings may be useful for the design and operation of secure communication networks.

A role for synapsin tetramerization in synaptic vesicle clustering.

Although synapsins have long been proposed to be key regulators of synaptic vesicle (SV) clustering, their mechanism of action has remained mysterious and somewhat controversial. Here, we review synapsins and their associations with each other and with SVs. We highlight the recent hypothesis that synapsin tetramerization is a mechanism for SV clustering. This hypothesis, which aligns with numerous experimental results, suggests that the larger size of synapsin tetramers, in comparison to dimers, allows tetramers to form optimal bridges between SVs that overcome the repulsive force associated with the negatively charged membrane of SVs and allow synapsins to form a reserve pool of SVs within presynaptic terminals.

Optical-Electrical Coordinately Modulated Memristor Based on 2D Ferroelectric RP Perovskite for Artificial Vision Applications.

Traditional artificial vision systems built using separate sensing, computing, and storage units have problems with high power consumption and latency caused by frequent data transmission between functional units. An effective approach is to transfer some memory and computing tasks to the sensor, enabling the simultaneous perception-storage-processing of light signals. Here, an optical-electrical coordinately modulated memristor is proposed, which controls the conductivity by means of polarization of the 2D ferroelectric Ruddlesden-Popper perovskite film at room temperature. The residual polarization shows no significant decay after 109-cycle polarization reversals, indicating that the device has high durability. By adjusting the pulse parameters, the device can simulate the bio-synaptic long/short-term plasticity, which enables the control of conductivity with a high linearity of ≈0.997. Based on the device, a two-layer feedforward neural network is built to recognize handwritten digits, and the recognition accuracy is as high as 97.150%. Meanwhile, building optical-electrical reserve pool system can improve 14.550% for face recognition accuracy, further demonstrating its potential for the field of neural morphological visual systems, with high density and low energy loss.

Organization of the Reserve Pool of Synaptic Vesicles in Nerve Terminals Lacking Protein Liquid Phase Components

Organization of the Reserve Pool of Synaptic Vesicles in Nerve Terminals Lacking Protein Liquid Phase Components

Presynaptic structural and functional plasticity are coupled by convergent Rap1 signaling.

Dynamic presynaptic actin remodeling drives structural and functional plasticity at synapses, but the underlying mechanisms remain largely unknown. Previous work has shown that actin regulation via Rac1 guanine exchange factor (GEF) Vav signaling restrains synaptic growth via bone morphogenetic protein (BMP)-induced receptor macropinocytosis and mediates synaptic potentiation via mobilization of reserve pool vesicles in presynaptic boutons. Here, we find that Gef26/PDZ-GEF and small GTPase Rap1 signaling couples the BMP-induced activation of Abelson kinase to this Vav-mediated macropinocytosis. Moreover, we find that adenylate cyclase Rutabaga (Rut) signaling via exchange protein activated by cAMP (Epac) drives the mobilization of reserve pool vesicles during post-tetanic potentiation (PTP). We discover that Rap1 couples activation of Rut-cAMP-Epac signaling to Vav-mediated synaptic potentiation. These findings indicate that Rap1 acts as an essential, convergent node for Abelson kinase and cAMP signaling to mediate BMP-induced structural plasticity and activity-induced functional plasticity via Vav-dependent regulation of the presynaptic actin cytoskeleton.

Parallel processing of quickly and slowly mobilized reserve vesicles in hippocampal synapses.

Vesicles within presynaptic terminals are thought to be segregated into a variety of readily releasable and reserve pools. The nature of the pools and trafficking between them is not well understood, but pools that are slow to mobilize when synapses are active are often assumed to feed pools that are mobilized more quickly, in a series. However, electrophysiological studies of synaptic transmission have suggested instead a parallel organization where vesicles within slowly and quickly mobilized reserve pools would separately feed independent reluctant- and fast-releasing subdivisions of the readily releasable pool. Here, we use FM-dyes to confirm the existence of multiple reserve pools at hippocampal synapses and a parallel organization that prevents intermixing between the pools, even when stimulation is intense enough to drive exocytosis at the maximum rate. The experiments additionally demonstrate extensive heterogeneity among synapses in the relative sizes of the slowly and quickly mobilized reserve pools, which suggests equivalent heterogeneity in the numbers of reluctant and fast-releasing readily releasable vesicles that may be relevant for understanding information processing and storage.

Parallel processing of quickly and slowly mobilized reserve vesicles in hippocampal synapses

Vesicles within presynaptic terminals are thought to be segregated into a variety of readily releasable and reserve pools. The nature of the pools and trafficking between them is not well understood, but pools that are slow to mobilize when synapses are active are often assumed to feed pools that are mobilized more quickly, in a series. However, electrophysiological studies of synaptic transmission have suggested instead a parallel organization where vesicles within slowly and quickly mobilized reserve pools would separately feed independent reluctant- and fast-releasing subdivisions of the readily releasable pool. Here, we use FM-dyes to confirm the existence of multiple reserve pools at hippocampal synapses and a parallel organization that prevents intermixing between the pools, even when stimulation is intense enough to drive exocytosis at the maximum rate. The experiments additionally demonstrate extensive heterogeneity among synapses in the relative sizes of the slowly and quickly mobilized reserve pools, which suggests equivalent heterogeneity in the numbers of reluctant and fast-releasing readily releasable vesicles that may be relevant for understanding information processing and storage.

Short-distance vesicle transport via phase separation

In addition to long-distance molecular motor-mediated transport, cellular vesicles also need to be moved at short distances with defined directions to meet functional needs in subcellular compartments but with unknown mechanisms. Such short-distance vesicle transport does not involve molecular motors. Here, we demonstrate, using synaptic vesicle (SV) transport as a paradigm, that phase separation of synaptic proteins with vesicles can facilitate regulated, directional vesicle transport between different presynaptic bouton sub-compartments. Specifically, a large coiled-coil scaffold protein Piccolo, in response to Ca2+ and via its C2A domain-mediated Ca2+ sensing, can extract SVs from the synapsin-clustered reserve pool condensate and deposit the extracted SVs onto the surface of the active zone protein condensate. We further show that the Trk-fused gene, TFG, also participates in COPII vesicle trafficking from ER to the ER-Golgi intermediate compartment via phase separation. Thus, phase separation may play a general role in short-distance, directional vesicle transport in cells.

Tegument ultrastructure in mother sporocysts of Bunocotyle progenetica (Markowski, 1936) Chabaud et Buttner, 1959 (Digenea: Hemiuridae)

This paper focuses on the fine structure of mother sporocysts, the least studied stage of the digenean life cycle. The ultrastructure of the tegument of mature mother sporocysts of Bunocotyle progenetica was examined by transmission electron microscopy and described in detail. The tegument of these parthenitae is represented by an outer anucleate syncytium connected with the deeper-lying tegumental cells by cytoplasmic bridges. Its outer plasma membrane forms minute leaf-like outgrowths and numerous deep invaginations in the shape of interconnected channels. These channels, which pass in various directions and permeate almost the entire outer syncytium, considerably amplify its surface area. The cytoplasm of the outer layer of the tegument contains large mitochondria, microtubules and rare dense secretory granules, whose contents are discharged into the lumen of the channels. Numerous pinocytotic vesicles originate from the plasma membrane of the channels. Small endocytic vesicles are transported along the cytoplasmic bridges to the tegumental cells, where endocytosed food material is sorted and broken down. These cells are characterized by a well-developed Golgi apparatus, which is represented by multiple stacks of cisternae, and the presence of numerous endosomes at different maturation stages and residual bodies. Some steps of endosomal maturation in the tegumental cells were traced. In addition to their digestive activity, tegumental cells produce secretory granules, which are transported to the outer syncytium after their maturation. It was shown for the first time that in mature parthenitae, the population of tegumental cells could be renewed at the expense of a reserve pool of undifferentiated cells. The ultrastructural features of the tegument of mother sporocysts of B. progenetica are discussed in light of the concept of the enhanced trophic function of the tegument in sporocysts lacking the alimentary canal.

Synapsin 2a tetramerisation selectively controls the presynaptic nanoscale organisation of reserve synaptic vesicles

Neurotransmitter release relies on the regulated fusion of synaptic vesicles (SVs) that are tightly packed within the presynaptic bouton of neurons. The mechanism by which SVs are clustered at the presynapse, while preserving their ability to dynamically recycle to support neuronal communication, remains unknown. Synapsin 2a (Syn2a) tetramerization has been suggested as a potential clustering mechanism. Here, we used Dual-pulse sub-diffractional Tracking of Internalised Molecules (DsdTIM) to simultaneously track single SVs from the recycling and the reserve pools, in live hippocampal neurons. The reserve pool displays a lower presynaptic mobility compared to the recycling pool and is also present in the axons. Triple knockout of Synapsin 1-3 genes (SynTKO) increased the mobility of reserve pool SVs. Re-expression of wild-type Syn2a (Syn2aWT), but not the tetramerization-deficient mutant K337Q (Syn2aK337Q), fully rescued these effects. Single-particle tracking revealed that Syn2aK337QmEos3.1 exhibited altered activity-dependent presynaptic translocation and nanoclustering. Therefore, Syn2a tetramerization controls its own presynaptic nanoclustering and thereby contributes to the dynamic immobilisation of the SV reserve pool.

PTPN11/Corkscrew Activates Local Presynaptic Mapk Signaling to Regulate Synapsin, Synaptic Vesicle Pools, and Neurotransmission Strength, with a Dual Requirement in Neurons and Glia.

Cytoplasmic protein tyrosine phosphatase nonreceptor type 11 (PTPN11) and Drosophila homolog Corkscrew (Csw) regulate the mitogen-activated protein kinase (MAPK) pathway via a conserved autoinhibitory mechanism. Disease-causing loss-of-function (LoF) and gain-of-function (GoF) mutations both disrupt this autoinhibition to potentiate MAPK signaling. At the Drosophila neuromuscular junction glutamatergic synapse, LoF/GoF mutations elevate transmission strength and reduce activity-dependent synaptic depression. In both sexes of LoF/GoF mutations, the synaptic vesicles (SV)-colocalized synapsin phosphoprotein tether is highly elevated at rest, but quickly reduced with stimulation, suggesting a larger SV reserve pool with greatly heightened activity-dependent recruitment. Transmission electron microscopy of mutants reveals an elevated number of SVs clustered at the presynaptic active zones, suggesting that the increased vesicle availability is causative for the elevated neurotransmission. Direct neuron-targeted extracellular signal-regulated kinase (ERK) GoF phenocopies both increased local presynaptic MAPK/ERK signaling and synaptic transmission strength in mutants, confirming the presynaptic regulatory mechanism. Synapsin loss blocks this elevation in both presynaptic PTPN11 and ERK mutants. However, csw null mutants cannot be rescued by wild-type Csw in neurons: neurotransmission is only rescued by expressing Csw in both neurons and glia simultaneously. Nevertheless, targeted LoF/GoF mutations in either neurons or glia alone recapitulate the elevated neurotransmission. Thus, PTPN11/Csw mutations in either cell type are sufficient to upregulate presynaptic function, but a dual requirement in neurons and glia is necessary for neurotransmission. Taken together, we conclude that PTPN11/Csw acts in both neurons and glia, with LoF and GoF similarly upregulating MAPK/ERK signaling to enhance presynaptic Synapsin-mediated SV trafficking.

Organization of the Reserve Pool of Synaptic Vesicles in Nerve Terminals Lacking Protein Liquid Phase Components

Organization of the Reserve Pool of Synaptic Vesicles in Nerve Terminals Lacking Protein Liquid Phase Components

CD38 promotes hematopoietic stem cell dormancy.

A subpopulation of deeply quiescent, so-called dormant hematopoietic stem cells (dHSCs) resides at the top of the hematopoietic hierarchy and serves as a reserve pool for HSCs. The state of dormancy protects the HSC pool from exhaustion throughout life; however, excessive dormancy may prevent an efficient response to hematological stresses. Despite the significance of dHSCs, the mechanisms maintaining their dormancy remain elusive. Here, we identify CD38 as a novel and broadly applicable surface marker for the enrichment of murine dHSCs. We demonstrate that cyclic adenosine diphosphate ribose (cADPR), the product of CD38 cyclase activity, regulates the expression of the transcription factor c-Fos by increasing the release of Ca2+ from the endoplasmic reticulum (ER). Subsequently, we uncover that c-Fos induces the expression of the cell cycle inhibitor p57Kip2 to drive HSC dormancy. Moreover, we found that CD38 ecto-enzymatic activity at the neighboring CD38-positive cells can promote human HSC quiescence. Together, CD38/cADPR/Ca2+/c-Fos/p57Kip2 axis maintains HSC dormancy. Pharmacological manipulations of this pathway can provide new strategies to improve the success of stem cell transplantation and blood regeneration after injury or disease.

Anti-Müllerian hormone induces autophagy to preserve the primordial follicle pool in mice.

The reserve pool of primordial follicles (PMFs) is finely regulated by molecules implicated in follicular growth or PMF survival. Anti-Müllerian hormone (AMH), produced by granulosa cells of growing follicles, is known for its inhibitory role in the initiation of PMF growth. We observed in a recent invivo study that injection of AMH into mice seemed to induce an activation of autophagy. Furthermore, injection of AMH into mice activates the transcription factor FOXO3A which is also known for its implication in autophagy regulation. Many studies highlighted the key role of autophagy in the ovary at different stages of folliculogenesis, particularly in PMF survival. Through an invitro approach with organotypic cultures of prepubertal mouse ovaries, treated or not with AMH, we aimed to understand the link among AMH, autophagy, and FOXO3A transcription factor. Autophagy and FOXO3A phosphorylation were analyzed by western blot. The expression of genes involved in autophagy was quantified by RT-qPCR. In our invitro model, we confirmed the decrease in FOXO3A phosphorylation and the induction of autophagy in ovaries incubated with AMH. AMH also induces the expression of genes involved in autophagy. Interestingly, most of these genes are known to be FOXO3A target genes. In conclusion, we have identified a new role for AMH, namely the induction of autophagy, probably through FOXO3A activation. Thus, AMH protects the ovarian reserve not only by inhibiting the growth of PMFs but also by enabling their survival through activation of autophagy.

Deeper: A shared liquidity decentralized exchange design for low trading volume tokens to enhance average liquidity

AbstractThis paper presents Deeper, a design for a decentralized exchange that enhances liquidity via reserve sharing. By doing this, it addresses the problem of shallow liquidity in low trading volume token pairs. Shallow liquidity impairs the functioning of on‐chain markets by creating room for unwanted phenomena such as high slippage and sandwich attacks. Deeper solves this by allowing liquidity providers of multiple trading pairs against a common token to share liquidity. This is achieved by creating a common reserve pool for the shared token that is accessible by each trading pair. Independent from the shared liquidity, providers are free to add liquidity to individual token pairs without any restriction. The trading between one token pair does not affect the price of other token pairs even though the reserve of the shared token changes. The proposed design is an extension of concentrated liquidity automated market maker DEXs that is simple enough to be implemented on smart contracts. This is demonstrated by providing a template for a hook‐based smart contract that adds our custom functionality to Uniswap V4. Experiments on historical prices show that for a batch consisting of eight trading pairs, Deeper enhances liquidity by over 2.6– . The enhancement in liquidity can be increased further by increasing the participating tokens in the shared pool. While providing shared liquidity, liquidity providers should be cautious of certain risks and pitfalls, which are described. Overall, Deeper enables the creation of fair markets for low trading volume token pairs.

УСОВЕРШЕНСТВОВАНИЕ ТРАЛОВОГО ПРОМЫСЛА ТЮЛЬКИ В АЗОВСКОМ МОРЕ В СОВРЕМЕННЫХ УСЛОВИЯХ ВОССТАНОВЛЕНИЯ ПОПУЛЯЦИЙ ОСЕТРОВЫХ РЫБ

Background. At present, the Black and Caspian Sea sprat (tyulka) is the least exploited species of the aquatic biological resources in the Azov and Black Sea Fishery Basin, although it has always been a valuable fishing target and a possible reserve pool for the increase of fish catches in the Basin. In the recent years, with the increasing number of midwater trawls allowed for using in the Black and Caspian Sea sprat (tyulka) fishery, all vessels transitioned to its trawl fishing; however, its total catch is decreasing, and the fishing results of these vessels are on the decline. Relevance. Taking into consideration the stock restoration occurring to the sturgeon fish species in the Azov Sea Basin in the recent years, it is necessary to take measures for maintaining this trend, as the Black and Caspian Sea sprat trawl fishing can result in increased mortality or injury of sturgeon fish and considerably damage their population. With a substantial decrease in the Black and Caspian Sea sprat fishing stock, the matter of stock restoration of the sturgeon fish species in the Azov Sea can induce the prohibition of the trawl operations in this water body, including the complete ban of the insufficiently profitable trawl fishing of the Black and Caspian Sea sprat in its current form. The aim of this article is to examine the design of the midwater trawls used in the Black and Caspian Sea sprat fishing in the Azov Sea, to investigate the global best practices in the trawl selectivity improvement, and to substantiate the main design characteristics for the specialized tyulka midwater trawls and means of their selectivity improvement. Methods. The standard methods of sample collection and data processing that could characterize fishing methods, gears and techniques for harvesting aquatic bioresources have been used. Results. The designs for the specialized trawls for the Black and Caspian Sea sprat fishing (exploitation) and methods for their selectivity improvement have been developed. Conclusion. These specialized trawls with the sorting units and a new principle of using otter boards (trawl doors) can increase fishing selectivity and mitigate possible damage inflicted by trawling to the populations of sturgeon fish species in the Azov Sea.

Dissection of alpha‐synuclein specific synaptic functions by gene editing

AbstractBackgroundDespite almost two decades of research, the physiologic role of α‐synuclein remains unclear. Mice lacking α‐syn only show mild phenotypes, and most mechanistic studies have been done either in α‐syn over‐expressing systems, or in mice lacking all three synuclein genes (α/β/γ). However, over‐expression of proteins can induce unwanted phenotypes, and ‘triple‐knockout’ synuclein mice have structural and physiologic changes that are not specific to α‐syn – complicating interpretations.MethodsWe used CRISPR technology to systematically inactivate or activate each synuclein gene in cultured mouse hippocampal neurons, ensuring that our manipulations did not lead to compensatory changes in the non‐targeted synucleins. Gene‐editing was followed by unbiased evaluation of physiology and ultrastructure using optical synaptic vesicle (SV) recycling assays, electrophysiologic recordings, single‐molecule trafficking assays, super‐resolution imaging, and electron microscopy.ResultsNeurotransmission is maintained at a range of different activity patterns, motivating us to evaluate the role of α‐syn under basal states as well as conditions involving trains of action potentials. Elimination of α‐syn led to substantial increases in basal exocytosis. Single‐molecule trafficking of SVs in these neurons indicated an increase in mobility of reserve pool vesicles when α‐syn was absent. Increasing endogenous α‐syn levels by CRISPRa had largely reciprocal effects. Recent studies in our lab found that phosphorylation of α‐syn at the Ser129‐site is a trigger for α‐syn function at the synapse. Augmenting α‐syn functionality by constitutive phosphorylation of the α‐syn Ser129‐site also triggered clustering of distal SV‐pools, consistent with a role for α‐syn in physiologic clustering of reserve pool vesicles. However, when neuronal activity was augmented by trains of action potentials, loss of α‐syn selectively attenuated endocytosis, with no effect on exocytosis. Super‐resolution imaging revealed that α‐syn was translocated to peri‐active zones upon stimulation, suggesting that the altered localization of α‐syn under these conditions resulted in facilitation of endocytosis. Finally, mass‐spectrometry data also indicate that α‐syn binds to an endocytosis‐enriched proteome under conditions that favor neuronal activity.ConclusionOur data provide clarity of the repertoire of a‐syn specific functions under different physiologic conditions.