Papers by Alejandro J Amoroso
Applied Biochemistry and Biotechnology, 2017
Low solubility of sterols in aqueous media limits efficient steroid production mediated by biocat... more Low solubility of sterols in aqueous media limits efficient steroid production mediated by biocatalytic microorganisms such as Mycobacterium. Sterol emulsion technologies have been developed with low success rates, largely due to the complexity of generating stable and bioavailable particles. In this study, several aqueous dispersions of sterols in-water of different particle sizes were bioconverted to 4-androstene-3,17-dione (AD) in a solvent-free environment, using a classic microorganism Mycobacterium sp. B3805 as a model system. According to our results, the high concentration (20 g/L) phytosterol dispersions with the smallest particle size tested (370 nm) achieved up to 54% (7.4 g/L) AD production yield in 11 days. Moreover, the use of 0.1 biomass/sterols ratio in a complex bioconversion media containing yeast extract, and a 1:1 glucose/ microdispersion ratio in the presence of the surfactant DK-Ester P-160 (HLB16), allowed homogenization and increased microdispersion stability, thus achieving the best results using emulsion technologies to date.
Research Square (Research Square), Apr 26, 2023
Mesenchymal stem cells (MSC) are recognized for their immunomodulatory effects and regenerative p... more Mesenchymal stem cells (MSC) are recognized for their immunomodulatory effects and regenerative properties, being promising therapeutic agents for a wide range of diseases. To ensure a localized effect of MSC in the organism, biobased hydrogels have been tested for their ability to acting as a matrixembedded to improves MSC targeted delivery. In this context, nanocellulose (NC) has been used for drug delivery, showing biocompatibility and, durability in time, but until now NC not been tested for MSC growth exploiting the size and aldehyde content of NC. In this study, cellulose nanocrystals (CNC), cellulose nano bers (CNF) and micro brillated cellulose (MFC) were studied after one-pot oxidation and further crosslinking with chitosan (mass ratio 1:5). Size and aldehyde content of oxidized NC samples were evaluated to analyze their in uence on the hydrogel's properties. The crosslinked hydrogels were analyzed by FESEM, swelling ability, FTIR, compression tests, thermal stability, and stability in culture cell conditions. Oxidized-MFC hydrogel improved the mechanical stability and swelling behavior, but it lacks stability at cell conditions possibly due to its low aldehyde content (0.54 mmol/g). Conversely, oxidized CNF and oxidized CNC formed suitable crosslinked hydrogels for cell adhesion, and for growing and proliferating of MSC 3D spheroids after 120 h. However, only hydrogel with PO-CNF/chitosan shows antibacterial activity as well as MSC proliferation.
Molecular Biology of the Cell, 2015
B-cell receptor (BCR) engagement with surface-tethered antigens leads to the formation of an immu... more B-cell receptor (BCR) engagement with surface-tethered antigens leads to the formation of an immune synapse, which facilitates antigen uptake for presentation to T-lymphocytes. Antigen internalization and processing rely on the early dynein-dependent transport of BCR–antigen microclusters to the synapse center, as well as on the later polarization of the microtubule-organizing center (MTOC). MTOC repositioning allows the release of proteases and the delivery of MHC class II molecules at the synapse. Whether and how these events are coordinated have not been addressed. Here we show that the ancestral polarity protein Par3 promotes BCR–antigen microcluster gathering, as well as MTOC polarization and lysosome exocytosis, at the synapse by facilitating local dynein recruitment. Par3 is also required for antigen presentation to T-lymphocytes. Par3 therefore emerges as a key molecule in the coupling of the early and late events needed for efficient extraction and processing of immobilized...
FEMS Microbiology Letters, 2009
The biodegradation of lignin is a highly oxidative process in which various oxidases and peroxida... more The biodegradation of lignin is a highly oxidative process in which various oxidases and peroxidases play a major role. During lignin decay, the generation of aromatic compounds and reactive oxygen species leads to oxidative stress. In this work, the effect of the oxidative compounds H 2 O 2 and hydroquinone in the ligninolytic fungus Ceriporiopsis subvermispora was studied, both at the ultrastructural and at the transcriptional level. Transmission electron microscopy revealed the presence of microvesicles and extensive cytoplasm degeneration after incubation with hydroquinone, but not with H 2 O 2 . Studies of the intracellular redox state of the fungus showed that hydroquinone causes a transient decrease in the reduced glutathione/oxidized glutathione (GSH/GSSG) ratio and an increase in the glutathione-S-transferase mRNA levels. These results suggest that hydroquinone produces oxidative stress in this microorganism. On the other hand, it was observed that hydroquinone, but not H 2 O 2 , affects Mn-dependent peroxide and laccase transcripts levels. We propose that the mechanism by which the fungus reacts against oxidative stress contributes to its selectivity toward lignin during wood decay.
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Papers by Alejandro J Amoroso