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Abstract Neuronal transmission relies on the regulated secretion of neurotransmitters, which are packed in synaptic vesicles (SVs). Hundreds of SVs accumulate at synaptic boutons. Despite being held together, SVs are highly mobile, so that they can be recruited to the plasma membrane for their rapid release during neuronal activity. However, how such confinement of SVs corroborates with their motility remains unclear. To bridge this gap, we employ ultrafast single-molecule tracking (SMT) in the reconstituted system of native SVs and in living neurons. SVs and synapsin 1, the most highly abundant synaptic protein, form condensates with liquid-like properties. In these condensates, synapsin 1 movement is slowed in both at short (i.e., 60-nm) and long (i.e., several hundred-nm) ranges, suggesting that the SV-synapsin 1 interaction raises the overall packing of the condensate. Furthermore, two-color SMT and super-resolution imaging in living axons demonstrate that synapsin 1 drives the accumulation of SVs in boutons. Even the short intrinsically-disordered fragment of synapsin 1 was sufficient to restore the native SV motility pattern in synapsin triple knock-out animals. Thus, synapsin 1 condensation is sufficient to guarantee reliable confinement and motility of SVs, allowing for the formation of mesoscale domains of SVs at synapses in vivo.

Objective: To investigate the in vitro antibacterial potential, phytochemical constituents and thinlayer chromatography (TLC) bioautography of Mesua ferrea and Piper cubeba fruit extracts. The antibacterial activities of various solvent extracts prepared were assessed against five multi-drug resistant clinical isolates from both Gram-negative and positive bacteria isolated from human infection. Materials and Methods: The antibacterial activity of solvent extracts from Mesua ferrea and Piper cubeba was evaluated by agar well diffusion method. The antibacterial activity was evaluated using the TLC-bioautographic method. Preliminary phytochemical analysis was conducted. Results: All the evaluated extracts exibited moderate to significant antibacterial activity against all clinical isolates except Klebsiella sp. and Pseudomonas aeruginosa. The maximum zone of inhibition was found to be 22.5 ± 0.90 mm in M. ferrea and17.6 ± 0.80 mm in P. cubeba against Enterococcus sp. The qualitative phytochemical analysis showed the presence of most of the phytochemicals such as flavonoids, steroids, reducing sugars, cardiac glycosides and triterpenoids in all the solvent extract tested. TLC and bioautography agar overlay assay of hexane extracts of M. ferrea indicated flavonoids as the active compounds against multidrug-resistant Enterococcus sp. Conclusions: The solvent extracts of both the plants possessing antibacterial potential against clinical isolates can be utilized in the treatment of microbial infections. [ABSTRACT FROM AUTHOR]

Air pollution due to anthropogenic activities imparts superfluous stress to plants and compels it to respond in the same manner as other environmental stress conditions. In an attempt to investigate the effects of air pollution on the biochemical properties of plants, the proline and the reducing sugar content of Saraca asoca was analysed in this study which so far has not been determined in this species. Biochemical properties for two different samples from similar ecological statues but exposed to varying levels of atmospheric pollution were analysed in this study. Saraca asoca was chosen due to its high relative abundance in both the locations. The samples were collected from both the locations and labelled as control sample (unpolluted site) and polluted sample (near commercial and industrial area). The results indicated an increase in the proline content in the polluted sample, signifying its role in the defence mechanism when the plant is under environmental stress. On the other hand, the reducing sugar content in polluted sample declined which indicated photosynthetic inhibition. These variations in biochemical parameters occurring as a consequence of air pollution help the plant to make maximum use of its resources during stress. Thus, biomonitoring with plants assists in a low-cost and beneficial method to indicate the degree of air pollution in an area. [ABSTRACT FROM AUTHOR]

Neuronal communication relies on precisely maintained synaptic vesicle (SV) clusters, which assemble via liquid-liquid phase separation (LLPS). This process requires synapsins, the major synaptic phosphoproteins, which are known to bind actin. The reorganization of SVs, synapsins and actin is a hallmark of synaptic activity, but their interplay is still unclear. Here we combined the reconstitution approaches and super-resolution imaging to dissect the roles of synapsin-SV condensates in the organization of the presynaptic actin cytoskeleton. Our data indicate that LLPS of synapsin initiates actin polymerization, allowing for SV:synapsin:actin assemblies to facilitate the mesoscale organization of SV clusters along axons mimicking the native presynaptic organization in both lamprey and mammalian synapses. Understanding the relationship between the actin network and synapsin-SVs condensates is an essential building block on a roadmap to unravel how coordinated neurotransmission along the axon enables circuit function and behavior., Competing Interests: Competing Interests. The authors declare no competing interests.