Search results for "glutamine"
showing 10 items of 122 documents
Alzheimer's disease: amino acid levels and brain metabolic status.
2013
Abstract To study brain free amino acids and their relation with dementia we measured, by high-performance liquid chromatography (HPLC), the concentration of eight free amino acids, amines and related compounds. We used temporal cortex (TC) samples obtained from 13 Alzheimer’s disease (AD) patients and an equal number of agematched controls (AC). The patterns of free amino acids, amines and related compounds showed significant quantitative changes in AD conditions with respect to healthy ones. In Alzheimer patients, lower levels of GABA were found in the TC (-57 %). Amino acids glutamate (Glu), and aspartate (Asp) concentrations, also appeared significantly reduced in the TC of AD patients …
Low Prevalence of Celiac Disease among Patients with Functional Gastrointestinal Disorders in Latvia.
2020
Background and Aims: Studies suggest that the prevalence of celiac disease (CD) is increased in individuals with functional gastrointestinal disorders (FGIDs), in particular, irritable bowel syndrome (IBS); however, the evidence is conflicting. We aimed to analyze the prevalence of CD in patients with FGIDs in Latvia.
 Methods: This retrospective study included patients with FGIDs, referred for a gastroenterologist consultation in a secondary gastroenterology practice unit. Patients were divided into three groups – patients only with IBS (IBS group), patients only with functional dyspepsia (FD) (FD group), patients with mixed symptoms IBS and FD (Mixed group). Patient levels of tissue …
Significance of gamma-glutamyltranspeptidase in exocrine pancreatic amino acid transport.
1991
The exocrine pancreas is rich in gamma-glutamyltranspeptidase (GGT, EC 2.3.2.2) and exhibits high rates of amino acid transport and protein synthesis. The role of the gamma-glutamyl cycle in mediating neutral amino acid transport in the isolated perfused rat pancreas was investigated using acivicin, an inhibitor of GGT, and a rapid dual isotope dilution technique. When treatment in vivo with acivicin (50 mg/kg) was followed 1 h later by continuous perfusion of the isolated pancreas with 10 microM acivicin, GGT levels decreased from 53 +/- 3 IU/g to 4.9 +/- 1.5 IU/g. This marked inhibition of GGT activity was not associated with decreased uptake for either L-alanine or L-glutamine, suggestin…
Gender-dependent behavioural impairment and brain metabolites in young adult rats after short term exposure to lead acetate
2012
We investigated the behavioural effects of short-term lead (Pb) exposure in adult rats producing blood Pb concentration (<10. μg/dL) below those associated with neurological impairment in occupationally exposed individuals. In order to assess gender differences, we performed parallel behavioural experiments in male and female rats. Exposure to Pb acetate (50. mg/L in drinking water) for 30-45 days induced behavioural alterations consisting in hyperactivity in a novel environment and impairment of spatial memory. These effects were observed only in male rats. Object recognition, motor coordination were unaffected by Pb exposure. Magnetic resonance spectroscopy allows . in vivo assessment of …
Targeting cells of the immune system: mannosylated HPMA–LMA block-copolymer micelles for targeting of dendritic cells
2016
Background: Successful tumor immunotherapy depends on the induction of strong and sustained tumor antigen-specific immune responses by activated antigen-presenting cells (APCs) such as dendritic cells (DCs). Since nanoparticles have the potential to codeliver tumor-specific antigen and DC-stimulating adjuvant in a DC-targeting manner, we wanted to assess the suitability of mannosylated HPMA-LMA block polymers for immunotherapy. Materials & methods: Fluorescence-labeled block copolymer micelles derived from P(HPMA)-block-P(LMA) copolymers and according statistical copolymers were synthesized via RAFT polymerization, and loaded with the APC activator L18-MDP. Both types of copolymers wer…
2019
The Gram-positive soil bacterium Bacillus subtilis relies on the glutamine synthetase and the glutamate synthase for glutamate biosynthesis from ammonium and 2-oxoglutarate. During growth with the carbon source glucose, the LysR-type transcriptional regulator GltC activates the expression of the gltAB glutamate synthase genes. With excess of intracellular glutamate, the gltAB genes are not transcribed because the glutamate-degrading glutamate dehydrogenases (GDHs) inhibit GltC. Previous in vitro studies revealed that 2-oxoglutarate and glutamate stimulate the activator and repressor function, respectively, of GltC. Here, we have isolated GltC variants with enhanced activator or repressor fu…
Evidence for an involvement of NMDA and non-NMDA receptors in synaptic excitation of phrenic motoneurons in the rabbit
1991
Abstract The action of endogenous excitatory amino acids on phrenic motoneurons was studied in anesthetized, vagotomized, paralyzed and artificially ventilated rabbits. The NMDA receptor antagonists APV and ketamine, as well as the non-NMDA receptor antagonists GAMS and DNQX were administered by microinjection into the ventral horn of the spinal segments C3-C5. Injection of each antagonist resulted in a reversible reduction of the phrenic nerve activity. Results suggest an important function of endogenous excitatory amino acids in the excitation of phrenic motneurons. NMDA as well as non-NMDA receptors are involved. The functional role of both receptor types in bulbospinal neurotransmission…
Conformational Changes in the Nucleosome Followed by the Selective Accessibility of Histone Glutamines in the Transglutaminase Reaction: Effects of …
2001
Transglutaminases, the enzymes that catalyze the acyl-transfer reaction between glutamine and primary amines, have been used to introduce probes into proteins in order to perform structural studies using physical techniques. Here we use an original approach in which the increasing accessibility of the glutamines of core histones to TGase is used to monitor the salt-induced conformational changes of the nucleosome. The rationale of this strategy is that the accessibility of a glutamine to transglutaminase depends on the blockage due to the presence of either other histones or DNA. At low ionic strength, only glutamines on the N-terminal tails of H2B and H3 are labeled with monodansylcadaveri…
The Protein Structure Context of PolyQ Regions.
2016
Proteins containing glutamine repeats (polyQ) are known to be structurally unstable. Abnormal expansion of polyQ in some proteins exceeding a certain threshold leads to neurodegenerative disease, a symptom of which are protein aggregates. This has led to extensive research of the structure of polyQ stretches. However, the accumulation of contradictory results suggests that protein context might be of importance. Here we aimed to evaluate the structural context of polyQ regions in proteins by analysing the secondary structure of polyQ proteins and their homologs. The results revealed that the secondary structure in polyQ vicinity is predominantly random coil or helix. Importantly, the region…
Molecular Architecture of Strictosidine Glucosidase: The Gateway to the Biosynthesis of the Monoterpenoid Indole Alkaloid Family[W]
2007
Abstract Strictosidine β-d-glucosidase (SG) follows strictosidine synthase (STR1) in the production of the reactive intermediate required for the formation of the large family of monoterpenoid indole alkaloids in plants. This family is composed of ∼2000 structurally diverse compounds. SG plays an important role in the plant cell by activating the glucoside strictosidine and allowing it to enter the multiple indole alkaloid pathways. Here, we report detailed three-dimensional information describing both native SG and the complex of its inactive mutant Glu207Gln with the substrate strictosidine, thus providing a structural characterization of substrate binding and identifying the amino acids …