Parkinson's disease (PD) is a neurodegenerative disorder characterized by the progressive loss of dopaminergic neurons in the substantia nigra (SN) pars compacta region of the brain. The main pathological hallmark involves cytoplasmic inclusions of αsynuclein and mitochondrial dysfunction, which is observed in other part of the central nervous system other than SN suggesting the spread of pathogenesis to bystander neurons. The inter-neuronal communication through exosomes may play an important role in the spread of the disease; however, the mechanisms are not well elucidated.Mitochondria and its role in inter-organellar crosstalk with multivesicular body (MVB) and lysosome and its role in modulation of exosome release in PD is not well understood. In the current study, we investigated the mitochondria-lysosome crosstalk modulating the exosome release in neuronal and glial cells. We observed that PD stress showed enhanced release of exosomes in dopaminergic neurons and glial cells. The PD stress condition in these cells showed fragmented network and mitochondrial dysfunction which further leads to functional deficit of lysosomes and hence inhibition of autophagy flux. Neuronal and glial cells treated with rapamycin showed enhanced autophagy and inhibited the exosomal release. The results here suggest that maintenance of mitochondrial function is important for the lysosomal function and hence exosomal release which is important for the pathogenesis of PD.

Exosomes are emerging intercellular communicators essential for cellular homeostasis during development and differentiation. The dysregulation in exosome-mediated communication alters cellular networking leads to developmental defects and chronic diseases. Exosomes are heterogeneous in nature depending on differences in size, membrane protein abundance, and differential cargo load. In this review, we have highlighted the latest developments in exosome biogenesis pathways, heterogeneity, and selective enrichment of various exosomal cargoes including proteins, nucleic acids, and mitochondrial DNA. Furthermore, the recent developments in the isolation techniques of exosome subpopulations have also been discussed. The comprehensive knowledge of extracellular vesicle (EV) heterogeneity and selective cargo enrichment during specific pathology may provide a clue for disease severity and early prognosis possibilities. The release of specific exosome subtypes is associated with the progression of specific disease type and hence a probable tool for therapeutics and biomarker development.

Hexavalent chromium Cr(VI) has emerged as a contaminant of prime concern for the environmentalists because of its improper disposal by tannery, dye, and electroplating industries. Adsorption is the most exploited method for its removal from industrial wastewater because of its high removal efficiency even at low Cr(VI) concentration, minimal sludge, and ease of regeneration. In recent years, several adsorbents of biological origin such as plants, algae, fungi, and bacteria have been explored for Cr(VI) remediation. This review comprehends the recent studies involving usage of biopolymer‐based nano‐composites with respect to its adsorption mechanisms, adsorption capacities, isotherms, and kinetics. The conventional abiotic and biotic techniques for removal of Cr(VI) are also discussed with a comparative insight of their adsorption capacity and removal efficiency. Nano‐biocomposites integrate the functional properties of both nanoparticles and biopolymers, which make them efficient biosorbents. Nano‐biocomposites offer a large surface area, reduced particle loss, minimal particle agglomeration on the surface, and high stability. Common kinetic models among the nano‐biocomposites,  and various equilibrium models are also analyzed to understand the mode of adsorption and associated factors. These materials are mostly found to follow monolayer adsorption with ion exchange, electrostatic interaction, and surface complexation as major players in the process.

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