Direct detection of humoral marker corelates of COVID-19, glycated HSA and hyperglycosylated IgG3, by MALDI-ToF mass spectrometry.

The prefusion Spike protein of SARS-CoV2 binds advanced glycation end product (AGE) glycated human serum albumin (HSA) and a higher mass, hyperglycosylated/glycated, IgG3, as determined by matrix assisted laser desorption mass spectrometry (MALDI-ToF MS). We set out to investigate if the total blood plasma of patients who had recovered from acute respiratory distress as a result of COVID-19, contained more glycated HSA and higher mass (glycosylated/glycated) IgG3 than those with only clinically mild or asymptomatic infections. A direct dilution and disulphide bond reduction method was development and applied to plasma samples from SARS-CoV2 seronegative (N = 30) and seropositive (N = 31) healthcare workers and 38 convalescent plasma samples from patients who had been admitted with acute respiratory distress syndrome (ARDS) associated with COVID-19. Patients recovering from COVID-19 ARDS had significantly higher mass, AGE-glycated HSA and higher mass IgG3 levels. This would indicate that increased levels and/or ratios of hyper-glycosylation (probably terminal sialic acid) IgG3 and AGE glycated HSA may be predisposition markers for development of ARDS as a result of COVID-19 infection. Furthermore, rapid direct analysis of plasma samples by MALDI-ToF MS for such humoral immune correlates of COVID-19 presents a feasible screening technology for the most at risk; regardless of age or known health conditions.

Proteomic profiling of the rat hippocampus from the kindling and pilocarpine models of epilepsy: potential targets in calcium regulatory network

Herein proteomic profiling of the rat hippocampus from the kindling and pilocarpine models of epilepsy was performed to achieve new potential targets for treating epileptic seizures. A total of 144 differently expressed proteins in both left and right hippocampi by two-dimensional electrophoresis coupled to matrix-assisted laser desorption-mass spectrometry were identified across the rat models of epilepsy. Based on network analysis, the majority of differentially expressed proteins were associated with Ca2+ homeostasis. Changes in ADP-ribosyl cyclase (ADPRC), lysophosphatidic acid receptor 3 (LPAR3), calreticulin, ubiquitin carboxyl-terminal hydrolase L1 (UCH-L1), synaptosomal nerve-associated protein 25 (SNAP 25) and transgelin 3 proteins were probed by Western blot analysis and validated using immunohistochemistry. Inhibition of calcium influx by 8-Bromo-cADP-Ribose (8-Br-cADPR) and 2-Aminoethyl diphenylborinate (2-APB) which act via the ADPRC and LPAR3, respectively, attenuated epileptic seizures. Considering a wide range of molecular events and effective role of calcium homeostasis in epilepsy, polypharmacy with multiple realistic targets should be further explored to reach the most effective treatments.

Oral berberine improves brain dopa/dopamine levels to ameliorate Parkinson’s disease by regulating gut microbiota

The phenylalanine–tyrosine–dopa–dopamine pathway provides dopamine to the brain. In this process, tyrosine hydroxylase (TH) is the rate-limiting enzyme that hydroxylates tyrosine and generates levodopa (l-dopa) with tetrahydrobiopterin (BH4) as a coenzyme. Here, we show that oral berberine (BBR) might supply H• through dihydroberberine (reduced BBR produced by bacterial nitroreductase) and promote the production of BH4 from dihydrobiopterin; the increased BH4 enhances TH activity, which accelerates the production of l-dopa by the gut bacteria. Oral BBR acts in a way similar to vitamins. The l-dopa produced by the intestinal bacteria enters the brain through the circulation and is transformed to dopamine. To verify the gut–brain dialog activated by BBR’s effect, Enterococcus faecalis or Enterococcus faecium was transplanted into Parkinson’s disease (PD) mice. The bacteria significantly increased brain dopamine and ameliorated PD manifestation in mice; additionally, combination of BBR with bacteria showed better therapeutic effect than that with bacteria alone. Moreover, 2,4,6-trimethyl-pyranylium tetrafluoroborate (TMP-TFB)-derivatized matrix-assisted laser desorption mass spectrometry (MALDI-MS) imaging of dopamine identified elevated striatal dopamine levels in mouse brains with oral Enterococcus, and BBR strengthened the imaging intensity of brain dopamine. These results demonstrated that BBR was an agonist of TH in Enterococcus and could lead to the production of l-dopa in the gut. Furthermore, a study of 28 patients with hyperlipidemia confirmed that oral BBR increased blood/fecal l-dopa by the intestinal bacteria. Hence, BBR might improve the brain function by upregulating the biosynthesis of l-dopa in the gut microbiota through a vitamin-like effect.

Probing the Formation of Isolated Cyclo-FF Peptide Clusters by Far-Infrared Action Spectroscopy

Small cyclic peptides containing phenylalanine residues are prone to aggregate in the gas phase into highly hydrophobic chains. A combination of laser desorption, mass spectrometry and conformational selective IR-UV action...

Low-temperature condensation of carbonaceous dust grains from PAHs

Interstellar carbon has been detected in both gas-phase molecules and solid particles. The goal of this study is to identify the link between these two phases of cosmic carbon. Here we report preliminary results on the low temperature formation of carbonaceous dust grains from gas-phase aromatic hydrocarbon precursors. This is done using the supersonic expansion of an argon jet seeded with aromatic molecules and exposed to an electrical discharge. We report experimental evidence of efficient carbon dust condensation from aromatic molecules including benzene and naphthalene. The molecular content of the solid grains is probed with laser desorption mass spectrometry. The mass spectra reveal a rich molecular composition including fragments of the parent molecule but also growth into larger molecular species.