Clusters of neuronal Neurofascin prefigure node of Ranvier position along single axons

The spacing of nodes of Ranvier crucially affects conduction properties along myelinated axons. It has been assumed that node position is primarily driven by the growth of myelin sheaths. Here, we reveal an additional mechanism of node positioning that is driven by the axon. We show through longitudinal live imaging of node formation dynamics that stable clusters of the cell adhesion molecule Neurofascin A accumulate at specific sites along axons prior to myelination. While some of these clusters change position upon encounter with growing myelin sheaths, others restrict sheath extension and are therefore predictive of future node position. Animals that lack full-length Neurofascin A showed increased internodal distances and less regular spacing of nodes along single axons. Together, our data reveal the existence of an axonal mechanism to position its nodes of Ranvier that does not depend on regulation of myelin sheath length.

Completion of neuronal remodeling prompts myelination along developing motor axon branches

Neuronal remodeling and myelination are two fundamental processes during neurodevelopment. How they influence each other remains largely unknown, even though their coordinated execution is critical for circuit function and often disrupted in neuropsychiatric disorders. It is unclear whether myelination stabilizes axon branches during remodeling or whether ongoing remodeling delays myelination. By modulating synaptic transmission, cytoskeletal dynamics, and axonal transport in mouse motor axons, we show that local axon remodeling delays myelination onset and node formation. Conversely, glial differentiation does not determine the outcome of axon remodeling. Delayed myelination is not due to a limited supply of structural components of the axon–glial unit but rather is triggered by increased transport of signaling factors that initiate myelination, such as neuregulin. Further, transport of promyelinating signals is regulated via local cytoskeletal maturation related to activity-dependent competition. Our study reveals an axon branch–specific fine-tuning mechanism that locally coordinates axon remodeling and myelination.

The Main Cluster Node Formation in Wireless Sensory Networks

In wireless sensor networks, the clustering method is often used to transmit information, which is one of the most energy efficient approaches. Since the master cluster node interacts with other nodes in the network, a node with a high residual energy is selected to perform its functions. The technology of selecting the main node based on fuzzy logic, which involves the use of a number of input parameters, the effect of which is demonstrated in the article, is proposed.

An alternative mechanism of early nodal clustering and myelination onset in GABAergic neurons of the central nervous system

SUMMARYIn vertebrates, fast saltatory conduction along myelinated axons relies on the node of Ranvier. How nodes assemble on CNS neurons is not yet fully understood. We recently highlighted that clusters similar to nodes can form prior to myelin deposition in hippocampal GABAergic neurons and are associated with increased conduction velocity. Here, we used a live imaging approach to characterize the intrinsic mechanisms underlying the assembly of these early clusters. We first demonstrated that their components can partially pre-assemble prior to membrane targeting and determined the molecular motors involved in their trafficking. We then demonstrated the key role of the protein β2Nav for clustering initiation. We further unraveled the fate of these early clusters, by showing that they participate in node formation, but also have an unexpected role in guiding oligodendrocyte processes prior to myelin deposition. Altogether our results shed light on an alternative mechanism of nodal clustering and myelination onset.

Aeroponic Cloning of Capsicum spp.

Aeroponic cloning is a great strategy to maintain desired genotypes by generating a whole new plant from cuttings. While this propagation technique has been demonstrated for tomatoes (Solanum lycopersicum) and potatoes (Solanum tuberosum), no protocol has been developed for peppers (Capsicum spp.). The ability to clonally propagate different Capsicum holds promise for domestic and industrial growing operations since elite cultivars with desirable traits (e.g., high capsaicin levels, nutrient content, and striped fruit) can be perpetuated without the need of planning a nursery. We tested six Capsicum species for their feasibility of aeroponic cloning by stem cuttings. All domestic species were successfully regenerated under aeroponic conditions but not for Capsicum eximium, a wild species. Of the species analyzed, Capsicum annuum peppers had the fastest node formation (11.6 +/− 0.89 days, P ≤ 0.01) and obtained a larger volume of roots (P ≤ 0.01) after node formation as compared to C. baccatum, C. frutescens, and C. pubescens. This study presents a cost-effective strategy to clonally propagate peppers for personal, industrial, and conservation purposes.