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1.
J Biotechnol ; 264: 29-37, 2017 Dec 20.
Article in English | MEDLINE | ID: mdl-29056529

ABSTRACT

Microbial polymers and nanomaterials production is a promising alternative for sustainable bioeconomics. To this end, we used Pseudomonas putida KT2440 as a cell factory in batch cultures to coproduce two important nanotechnology materials- medium-chain-length (MCL)-polyhydroxyalkanoates (PHAs) and CdS fluorescent nanoparticles (i.e. quantum dots [QDots]). Due to high cadmium resistance, biomass and PHA yields were almost unaffected by coproduction conditions. Fluorescent nanocrystal biosynthesis was possible only in presence of cysteine. Furthermore, this process took place exclusively in the cell, displaying the classical emission spectra of CdS QDots under UV-light exposure. Cell fluorescence, zeta potential values, and particles size of QDots depended on cadmium concentration and exposure time. Using standard PHA-extraction procedures, the biosynthesized QDots remained associated with the biomass, and the resulting PHAs presented no traces of CdS QDots. Transmission electron microscopy located the synthesized PHAs in the cell cytoplasm, whereas CdS nanocrystals were most likely located within the periplasmic space, exhibiting no apparent interaction. This is the first report presenting the microbial coproduction of MCL-PHAs and CdS QDots in P. putida KT2440, thus constituting a foundation for further bioprocess developments and strain engineering towards the efficient synthesis of these highly relevant bioproducts for nanotechnology.


Subject(s)
Cadmium Compounds/metabolism , Polyhydroxyalkanoates/metabolism , Pseudomonas putida/metabolism , Quantum Dots/metabolism , Sulfides/metabolism , Cadmium Compounds/chemistry , Particle Size , Polyhydroxyalkanoates/analysis , Polyhydroxyalkanoates/chemistry , Polyhydroxyalkanoates/isolation & purification , Quantum Dots/chemistry , Sulfides/chemistry
2.
Biotechnol Prog ; 32(3): 554-67, 2016 05.
Article in English | MEDLINE | ID: mdl-27006260

ABSTRACT

Stem cell-based approaches offer great application potential in tissue engineering and regenerative medicine owing to their ability of sensing the microenvironment and respond accordingly (dynamic behavior). Recently, the combination of nanobiomaterials with stem cells has paved a great way for further exploration. Nanobiomaterials with engineered surfaces could mimic the native microenvironment to which the seeded stem cells could adhere and migrate. Surface functionalized nanobiomaterial-based scaffolds could then be used to regulate or control the cellular functions to culture stem cells and regenerate damaged tissues or organs. Therefore, controlling the interactions between nanobiomaterials and stem cells is a critical factor. However, surface functionalization or modification techniques has provided an alternative approach for tailoring the nanobiomaterials surface in accordance to the physiological surrounding of a living cells; thereby, enhancing the structural and functional properties of the engineered tissues and organs. Currently, there are a variety of methods and technologies available to modify the surface of biomaterials according to the specific cell or tissue properties to be regenerated. This review highlights the trends in surface modification techniques for nanobiomaterials and the biological relevance in stem cell-based tissue engineering and regenerative medicine. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:554-567, 2016.


Subject(s)
Nanostructures/chemistry , Regenerative Medicine , Stem Cells/cytology , Tissue Culture Techniques , Tissue Engineering , Humans , Surface Properties
3.
Pain ; 155(10): 2108-15, 2014 Oct.
Article in English | MEDLINE | ID: mdl-25102401

ABSTRACT

Pannexin 1 (panx1) is a large-pore membrane channel expressed in many tissues of mammals, including neurons and glial cells. Panx1 channels are highly permeable to calcium and adenosine triphosphatase (ATP); on the other hand, they can be opened by ATP and glutamate, two crucial molecules for acute and chronic pain signaling in the spinal cord dorsal horn, thus suggesting that panx1 could be a key component for the generation of central sensitization during persistent pain. In this study, we examined the effect of three panx1 blockers, namely, 10panx peptide, carbenoxolone, and probenecid, on C-reflex wind-up activity and mechanical nociceptive behavior in a spared nerve injury neuropathic rat model involving sural nerve transection. In addition, the expression of panx1 protein in the dorsal horn of the ipsilateral lumbar spinal cord was measured in sural nerve-transected and sham-operated control rats. Sural nerve transection resulted in a lower threshold for C-reflex activation by electric stimulation of the injured hindpaw, together with persistent mechanical hypersensitivity to pressure stimuli applied to the paw. Intrathecal administration of the panx1 blockers significantly depressed the spinal C-reflex wind-up activity in both neuropathic and sham control rats, and decreased mechanical hyperalgesia in neuropathic rats without affecting the nociceptive threshold in sham animals. Western blotting showed that panx1 was similarly expressed in the dorsal horn of lumbar spinal cord from neuropathic and sham rats. The present results constitute the first evidence that panx1 channels play a significant role in the mechanisms underlying central sensitization in neuropathic pain.


Subject(s)
Carbenoxolone/therapeutic use , Connexins/antagonists & inhibitors , Hyperalgesia/drug therapy , Nerve Tissue Proteins/antagonists & inhibitors , Neuralgia/drug therapy , Probenecid/therapeutic use , Reflex/drug effects , Spinal Cord/drug effects , Animals , Carbenoxolone/pharmacology , Connexins/metabolism , Hyperalgesia/etiology , Hyperalgesia/metabolism , Male , Nerve Tissue Proteins/metabolism , Neuralgia/etiology , Neuralgia/metabolism , Pain Threshold/drug effects , Peripheral Nerve Injuries/complications , Posterior Horn Cells/drug effects , Posterior Horn Cells/metabolism , Probenecid/pharmacology , Rats , Rats, Sprague-Dawley , Spinal Cord/metabolism
4.
Thyroid ; 22(9): 951-63, 2012 Sep.
Article in English | MEDLINE | ID: mdl-22870949

ABSTRACT

BACKGROUND: Adult hypothyroidism is a highly prevalent condition that impairs processes, such as learning and memory. Even though tetra-iodothyronine (T(4)) treatment can overcome the hypothyroidism in the majority of cases, it cannot fully recover the patient's learning capacity and memory. In this work, we analyzed the cellular and molecular changes in the adult brain occurring with the development of experimental hypothyroidism. METHODS: Adult male Sprague-Dawley rats were treated with 6-propyl-2-thiouracil (PTU) for 20 days to induce hypothyroidism. Neuronal and astrocyte apoptosis were analyzed in the hippocampus of control and hypothyroid adult rats by confocal microscopy. The content of brain-derived neurotrophic factor (BDNF) was analyzed using enzyme-linked immunosorbent assay (ELISA) and in situ hybridization. The glutamatergic synapse and the postsynaptic density (PSD) were analyzed by electron microscopy. The content of PSD proteins like tyrosine receptor kinase B (TrkB), p75, and N-methyl-D-aspartate receptor (NMDAr) were analyzed by immunoblot. RESULTS: We observed that the hippocampus of hypothyroid adult rats displayed increased apoptosis levels in neurons and astrocyte and reactive gliosis compared with controls. Moreover, we found that the amount of BDNF mRNA was higher in the hippocampus of hypothyroid rats and the content of TrkB, the receptor for BDNF, was reduced at the PSD of the CA3 region of hypothyroid rats, compared with controls. We also observed that the glutamatergic synapses from the stratum radiatum of CA3 from hypothyroid rats, contained thinner PSDs than control rats. This observation was in agreement with a reduced content of NMDAr subunits at the PSD in hypothyroid animals. CONCLUSIONS: Our data suggest that adult hypothyroidism affects the hippocampus by a mechanism that alters the composition of PSD, reduces neuronal and astrocyte survival, and alters the content of the signaling neurotrophic factors, such as BDNF.


Subject(s)
Astrocytes/pathology , Brain-Derived Neurotrophic Factor/metabolism , Gliosis/pathology , Hypothyroidism/complications , Neurons/pathology , Post-Synaptic Density/pathology , Animals , Antithyroid Agents/adverse effects , Apoptosis/drug effects , Astrocytes/drug effects , Brain-Derived Neurotrophic Factor/analysis , Gliosis/chemically induced , Hippocampus/chemistry , Hippocampus/drug effects , Hippocampus/pathology , Hippocampus/ultrastructure , Hypothyroidism/chemically induced , Male , Neurons/drug effects , Post-Synaptic Density/chemistry , Post-Synaptic Density/drug effects , Propylthiouracil/adverse effects , Rats , Rats, Sprague-Dawley , Receptor, trkB/analysis , Receptors, N-Methyl-D-Aspartate/analysis
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