Analysis of 26 amino acids in human plasma by HPLC using AQC as derivatizing agent and its application in metabolic laboratory

The present study reports the simultaneous analysis of 26 physiological amino acids in plasma along with total cysteine and homocysteine by high-performance liquid chromatography (HPLC) employing 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate (AQC) as precolumn derivatizing reagent. Separations were carried out using Lichrospher 100 RP-18e (5 μm) 250 × 4.0 mm column connected to 100 CN 4.0 × 4.0 mm guard column on a quaternary HPLC system and run time was 53 min. Linearity of the peak areas for different concentrations ranging from 2.5 to 100 pmol/μL of individual amino acids was determined. A good linearity (R ² > 0.998) was achieved in the standard mixture for each amino acid. Recovery of amino acids incorporated at the time of derivatization ranged from 95 to 106 %. Using this method we have established the normative data of amino acids in plasma, the profile being comparable to the range reported in literature and identified cases of classical homocystinuria, cobalamin defect/deficiency, non-ketotic hyperglycinemia, hyperprolinemia, ketotic hyperglycinemia, urea cycle defect and maple syrup urine disease.     

FcγRIIb Inhibits Allergic Lung Inflammation in a Murine Model of Allergic Asthma

Allergic asthma is characterized by airway eosinophilia, increased mucin production and allergen-specific IgE. Fc gamma receptor IIb (FcγRIIb), an inhibitory IgG receptor, has recently emerged as a negative regulator of allergic diseases like anaphylaxis and allergic rhinitis. However, no studies to date have evaluated its role in allergic asthma. Our main objective was to study the role of FcγRIIb in allergic lung inflammation. We used a murine model of allergic airway inflammation. Inflammation was quantified by BAL inflammatory cells and airway mucin production. FcγRIIb expression was measured by qPCR and flow cytometry and the cytokines were quantified by ELISA. Compared to wild type animals, FcγRIIb deficient mice mount a vigorous allergic lung inflammation characterized by increased bronchoalveolar lavage fluid cellularity, eosinophilia and mucin content upon ragweed extract (RWE) challenge. RWE challenge in sensitized mice upregulated FcγRIIb in the lungs. Disruption of IFN-γ gene abrogated this upregulation. Treatment of naïve mice with the Th1-inducing agent CpG DNA increased FcγRIIb expression in the lungs. Furthermore, treatment of sensitized mice with CpG DNA prior to RWE challenge induced greater upregulation of FcγRIIb than RWE challenge alone. These observations indicated that RWE challenge upregulated FcγRIIb in the lungs by IFN-γ- and Th1-dependent mechanisms. RWE challenge upregulated FcγRIIb on pulmonary CD14+/MHC II+ mononuclear cells and CD11c+ cells. FcγRIIb deficient mice also exhibited an exaggerated RWE-specific IgE response upon sensitization when compared to wild type mice. We propose that FcγRIIb physiologically regulates allergic airway inflammation by two mechanisms: 1) allergen challenge mediates upregulation of FcγRIIb on pulmonary CD14+/MHC II+ mononuclear cells and CD11c+ cells by an IFN-γ dependent mechanism; and 2) by attenuating the allergen specific IgE response during sensitization. Thus, stimulating FcγRIIb may be a therapeutic strategy in allergic airway disorders.     

Functional recovery after transplantation of bone marrow-derived human mesenchymal stromal cells in a rat model of spinal cord injury

Background aimsSpinal cord injury (SCI) is a medically untreatable condition for which stem cells have created hope. Pre-clinical and clinical studies have established that these cells are safe for transplantation. The dose dependency, survivability, route of administration, cell migration to injury site and effect on sensory and motor behavior in an SCI-induced paraplegic model were studied.MethodsA spinal cord contusion injury model was established in rats. Bone marrow (BM) mesenchymal stromal cells (MSC) were tagged to facilitate tracing in vivo. Two different doses (2 and 5 million cells/kg body weight) and two different routes of infusion (site of injury and lumbar puncture) were tested during and after the spinal shock period. The animals were tested post-transplantation for locomotor capacity, motor control, sensory reflex, posture and body position. Stem cell migration was observed 1 month post-transplantation in spinal cord sections.ResultsThe overall results demonstrated that transplantation of BM MSC significantly improved the locomotor and sensory behavior score in the experimental group compared with the sham control group, and these results were dose dependent. All the infused stem cells could be visualized at the site of injury and none was visualized at the injected site. This indicated that the cells had survived in vivo, were probably chemoattracted and had migrated to the lesion site.ConclusionsMSC transplanted with a lumbar puncture method migrate to the site of injury and are the most suitable for SCI healing. These cells demonstrate a dose-dependent effect and promote functional recovery when injected during or after the spinal shock period.     

Micromanipulation of culture niche permits long-term expansion of dental pulp stem cells—an economic and commercial angle

Stem cells isolated from dental pulp possess the capacity for self-renewal and the potential for multi-lineage differentiation. However, dental pulp stem cells have different characteristics in terms of their culture conditions. The success of stem cells culture is governed by its micro-environmental niche. Therefore, we studied the effects of culture niche on long-term expansion of dental pulp stem cells in terms of cell morphology, growth kinetics, senescence pattern, cell surface marker expression differentiation capacity, and seeding plating density of dental pulp stem cells in four different, widely used media composition Among the various basal media tested, α-minimum essential media and knock out-minimum essential media supplemented with 10% fetal bovine serum were found to be the most optimal media composition in preserving the phenotypic characteristics and differentiation potential for prolonged periods as compared with DMEM-F12 and DMEM-LG. Plating density has been shown to affect overall yield. As a conclusion, the adoption of an appropriate culture system significantly improved cell yield, thus enabling the attainment of sufficient yields for therapeutic applications economizing in terms of cost of production and minimizing seeding cell density for maximum yield.     

2-Amino-5-benzoyl-4-phenylthiazoles: Development of potent and selective adenosine A1 receptor antagonists

A series of 2-amino-5-benzoyl-4-phenylthiazole derivatives was investigated in radioligand binding studies at adenosine receptor (AdoR) subtypes with the goal to obtain potent and A₁-selective antagonists. Acylation of the 2-amino group was found to be crucial for high A₁ affinity. The best compound of the present series was 2-benzoylamino-5-p-methylbenzoyl-4-phenylthiazole (16m) showing a K_i value of 4.83 nM at rat and 57.4 nM at human A₁ receptors combined with high selectivity versus the other AdoR subtypes. The compound behaved as an antagonist in GTP shift assays at A₁ receptors. Compound 16m may serve as a new lead structure for the development of second-generation non-xanthine-derived A₁ antagonists which have potential as novel drugs.     

GFP tagging based method to analyze the genome editing efficiency of CRISPR/Cas9-gRNAs through transient expression in N. benthamiana

The CRISPR/Cas9 (Clustered regularly interspaced short palindromic repeats/CRISPR—associated proteins 9) is simple and highly efficient technology applied to functional studies of genes and genetic crop improvement. In this study, we have demonstrated the utility of green fluorescent protein (GFP) marker to detect the targeting efficiency of gRNAs. As a proof of concept, Glycine max De-Etiolated 1 (GmDET1) gene was chosen and tagged with GFP to rapidly analyze genome editing efficiency of gRNAs. Results showed weaker GFP fluorescence signal in the N. benthamiana leaves co-infiltrated with GmDET1-GFP overexpression (OE)?+?DET1 gRNA1 constructs as compared to the stronger GFP florescence signal in the leaves co-infiltrated with DET1 gRNA2 and gRNA3 constructs, thus indicating the highest of DET1 gRNA1. These results were further confirmed by the detection of the mutation frequencies through T7 endonuclease (T7E1) assay and sequencing; the highest mutation rate of 38.46% in GmDET1 targeted by DET1 gRNA1 to that of DET1 gRNA2 (7.69%) and gRNA3 (15.38%) was observed. Thus our studies showed “GFP tagging” as the most reliable and rapid method-one can apply to minimize the generation of non-edited transgenic plants resulting from inefficient gRNAs.

     

Engineering of Ralstonia eutropha H16 for Autotrophic and Heterotrophic Production of Methyl Ketones

Ralstonia eutropha is a facultatively chemolithoautotrophic bacterium able to grow with organic substrates or H₂ and CO₂ under aerobic conditions. Under conditions of nutrient imbalance, R. eutropha produces copious amounts of poly[(R)-3-hydroxybutyrate] (PHB). Its ability to utilize CO₂ as a sole carbon source renders it an interesting new candidate host for the production of renewable liquid transportation fuels. We engineered R. eutropha for the production of fatty acid-derived, diesel-range methyl ketones. Modifications engineered in R. eutropha included overexpression of a cytoplasmic version of the TesA thioesterase, which led to a substantial (>150-fold) increase in fatty acid titer under certain conditions. In addition, deletion of two putative β-oxidation operons and heterologous expression of three genes (the acyl coenzyme A oxidase gene from Micrococcus luteus and fadB and fadM from Escherichia coli) led to the production of 50 to 65 mg/liter of diesel-range methyl ketones under heterotrophic growth conditions and 50 to 180 mg/liter under chemolithoautotrophic growth conditions (with CO₂ and H₂ as the sole carbon source and electron donor, respectively). Induction of the methyl ketone pathway diverted substantial carbon flux away from PHB biosynthesis and appeared to enhance carbon flux through the pathway for biosynthesis of fatty acids, which are the precursors of methyl ketones.     

Fundamental increase in pressure-dependent constriction of brain parenchymal arterioles from subarachnoid hemorrhage model rats due to membrane depolarization

S-nitrosation of thiols in key proteins in cell signaling pathways is thought to be an important contributor to nitric oxide (NO)-dependent control of vascular (patho)physiology. Multiple metabolic enzymes are targets of both NO and S-nitrosation, including those involved in glycolysis and oxidative phosphorylation. Thus it is important to understand how these metabolic pathways are integrated by NO-dependent mechanisms. Here, we compared the effects of NO and S-nitrosation on both glycolysis and oxidative phosphorylation in bovine aortic endothelial cells using extracellular flux technology to determine common and unique points of regulation. The compound S-nitroso-L-cysteine (L-CysNO) was used to initiate intracellular S-nitrosation since it is transported into cells and results in stable S-nitrosation in vitro. Its effects were compared with the NO donor DetaNONOate (DetaNO). DetaNO treatment caused only a decrease in the reserve respiratory capacity; however, L-CysNO impaired both this parameter and basal respiration in a concentration-dependent manner. In addition, DetaNO stimulated extracellular acidification rate (ECAR), a surrogate marker of glycolysis, whereas L-CysNO stimulated ECAR at low concentrations and inhibited it at higher concentrations. Moreover, a temporal relationship between NO- and S-nitrosation-mediated effects on metabolism was identified, whereby NO caused a rapid impairment in mitochondrial function, which was eventually overwhelmed by S-nitrosation-dependent processes. Taken together, these results suggest that severe pharmacological nitrosative stress may differentially regulate metabolic pathways through both intracellular S-nitrosation and NO-dependent mechanisms. Moreover, these data provide insight into the role of NO and related compounds in vascular (patho)physiology.