The combination of nanodroplet sample preparation, ultra-low-flow nanoLC, high-field asymmetric ion mobility spectrometry (FAIMS) and latest-generation mass spectrometry instrumentation provides dramatically improved single-cell proteome profiling.

Azoreductases are diverse flavoenzymes widely present among microorganisms and higher eukaryotes. They are mainly involved in the biotransformation and detoxification of azo dyes, nitro-aromatic, and azoic drugs. Reduction of azo bond and reductive activation of pro-drugs at initial level is a crucial stage in degradation and detoxification mechanisms. Using azoreductase-based microbial enzyme systems that are biologically accepted and ecofriendly demonstrated complete degradation of azo dyes. Azoreductases are flavin-containing or flavin-free group of enzymes, utilizing the nicotinamide adenine dinucleotide or nicotinamide adenine dinucleotide phosphate as a reducing equivalent. Azoreductases from anaerobic microorganisms are highly oxygen sensitive, while azoreductases from aerobic microorganisms are usually oxygen insensitive. They have variable pH, temperature stability, and wide substrate specificity. Azo dyes, nitro-aromatic compounds, and quinones are the known substrates of azoreductase. The present review gives an overview of recent developments in the known azoreductase enzymes from different microorganisms, its novel classification scheme, significant characteristics, and their plausible degradation mechanisms.

A limitation of conventional bulk-tissue proteome studies in amyotrophic lateral sclerosis (ALS) is the confounding of motor neuron (MN) signals by admixed non-MN proteins. Here, we leverage laser capture microdissection and nanoPOTS single-cell mass spectrometry-based proteomics to query changes in protein expression in single MNs from postmortem ALS and control tissues. In a follow-up analysis, we examine the impact of stratification of MNs based on cytoplasmic transactive response DNA-binding protein 43 (TDP-43)+ inclusion pathology on the profiles of 2,238 proteins. We report extensive overlap in differentially abundant proteins identified in ALS MNs with or without overt TDP-43 pathology, suggesting early and sustained dysregulation of cellular respiration, mRNA splicing, translation, and vesicular transport in ALS. Together, these data provide insights into proteome-level changes associated with TDP-43 proteinopathy and begin to demonstrate the utility of pathology-stratified trace sample proteomics for understanding single-cell protein dynamics in human neurologic diseases.