ABSTRACT
BACKGROUND: Routine prenatal care fails to identify a large proportion of women at risk of fetal growth restriction (FGR). Metabolomics, the comprehensive analysis of low molecular weight molecules (metabolites) in biological samples, can provide new and earlier biomarkers of prenatal health. Recent research has suggested possible predictive first trimester urine metabolites correlating to fetal growth restriction in the third trimester. Our objective in this current study was to examine urinary metabolic profiles in the first and second trimester of pregnancy in relation to third trimester FGR in a US population from a large, multi-center cohort study of healthy pregnant women. METHODS: We conducted a nested case-control study within The Infant Development and the Environment Study (TIDES), a population-based multi-center pregnancy cohort study. We identified 53 cases of FGR based on the AUDIPOG [Neonatal growth - AUDIPOG [Internet]. [cited 29 Nov 2016]. Available from: http://www.audipog.net/courbes_morpho.php?langue=en ] formula for birthweight percentile considering maternal height, age, and prenatal weight, as well as infant sex, gestational age, and birth rank. Cases were matched to 106 controls based on study site, maternal age (± 2 years), parity, and infant sex. NMR spectroscopy was used to assess concentrations of four urinary metabolites that have been previously associated with FGR (tyrosine, acetate, formate, and trimethylamine) in first and second trimester urine samples. We fit multivariate conditional logistic regression models to estimate the odds of FGR in relation to urinary concentrations of these individual metabolites in the first and second trimesters. Exploratory analyses of custom binned spectroscopy results were run to consider other potentially related metabolites. RESULTS: We found no significant association between the relative concentrations of each of the four metabolites and odds of FGR. Exploratory analyses did not reveal any significant differences in urinary metabolic profiles. Compared with controls, cases delivered earlier (38.6 vs 39.8, p < 0.001), and had lower birthweights (2527 g vs 3471 g, p < 0.001). Maternal BMI was similar between cases and controls. CONCLUSIONS: First and second trimester concentrations of urinary metabolites (acetate, formate, trimethylamine and tyrosine) did not predict FGR. This inconsistency with previous studies highlights the need for more rigorous investigation and data collection in this area before metabolomics can be clinically applied to obstetrics.
Subject(s)
Fetal Growth Retardation/etiology , Pregnancy Trimester, First/urine , Pregnancy Trimester, Second/urine , Urine/chemistry , Acetates/urine , Adult , Case-Control Studies , Female , Formates/urine , Gestational Age , Humans , Infant, Low Birth Weight , Infant, Newborn , Logistic Models , Maternal Age , Metabolome , Methylamines/urine , Multivariate Analysis , Odds Ratio , Pregnancy , Risk Assessment , Risk Factors , Tyrosine/urine , United StatesABSTRACT
AIMS: To compare the efficacy and safety of two titration algorithms for insulin degludec/insulin aspart (IDegAsp) administered once daily with metformin in participants with insulin-naïve Type 2 diabetes mellitus. METHODS: This open-label, parallel-group, 26-week, multicentre, treat-to-target trial, randomly allocated participants (1:1) to two titration arms. The Simple algorithm titrated IDegAsp twice weekly based on a single pre-breakfast self-monitored plasma glucose (SMPG) measurement. The Stepwise algorithm titrated IDegAsp once weekly based on the lowest of three consecutive pre-breakfast SMPG measurements. In both groups, IDegAsp once daily was titrated to pre-breakfast plasma glucose values of 4.0-5.0 mmol/l. Primary endpoint was change from baseline in HbA1c (%) after 26 weeks. RESULTS: Change in HbA1c at Week 26 was IDegAspSimple -14.6 mmol/mol (-1.3%) (to 52.4 mmol/mol; 6.9%) and IDegAspStepwise -11.9 mmol/mol (-1.1%) (to 54.7 mmol/mol; 7.2%). The estimated between-group treatment difference was -1.97 mmol/mol [95% confidence interval (CI) -4.1, 0.2] (-0.2%, 95% CI -0.4, 0.02), confirming the non-inferiority of IDegAspSimple to IDegAspStepwise (non-inferiority limit of ≤ 0.4%). Mean reduction in fasting plasma glucose and 8-point SMPG profiles were similar between groups. Rates of confirmed hypoglycaemia were lower for IDegAspStepwise [2.1 per patient years of exposure (PYE)] vs. IDegAspSimple (3.3 PYE) (estimated rate ratio IDegAspSimple /IDegAspStepwise 1.8; 95% CI 1.1, 2.9). Nocturnal hypoglycaemia rates were similar between groups. No severe hypoglycaemic events were reported. CONCLUSIONS: In participants with insulin-naïve Type 2 diabetes mellitus, the IDegAspSimple titration algorithm improved HbA1c levels as effectively as a Stepwise titration algorithm. Hypoglycaemia rates were lower in the Stepwise arm.
Subject(s)
Diabetes Mellitus, Type 2/drug therapy , Hypoglycemic Agents/administration & dosage , Insulin, Long-Acting/administration & dosage , Aged , Blood Glucose/metabolism , Blood Glucose Self-Monitoring , Diabetes Mellitus, Type 2/metabolism , Drug Combinations , Drug Therapy, Combination , Female , Glycated Hemoglobin/metabolism , Humans , Hypoglycemia/chemically induced , Hypoglycemic Agents/therapeutic use , Insulin, Long-Acting/adverse effects , Male , Metformin/therapeutic use , Middle Aged , Treatment OutcomeABSTRACT
AIM: To evaluate the efficacy and safety of twice-daily insulin degludec/insulin aspart vs. twice-daily biphasic insulin aspart 30 in people with Type 2 diabetes mellitus who were naïve to insulin. METHODS: In this 26-week, multinational, open-label, controlled, two-arm, parallel-group, treat-to-target trial, participants [mean (± sd) age 58.9 (±8.9) years, duration of diabetes 9.5 (±5.9) years, HbA1c 68 (±8.7) mmol/mol or 8.4 (±0.8)% and BMI 31.2 (±4.2) kg/m(2) ) were randomized (1:1) to insulin degludec/insulin aspart (n = 197) or biphasic insulin aspart 30 (n = 197), administered with breakfast and the main evening meal, titrated to a self-monitored plasma glucose target > 3.9 and ≤ 5.0 mmol/l. RESULTS: The mean HbA1c was reduced to 49 mmol/mol (6.6%) with insulin degludec/insulin aspart and 48 mmol/mol (6.5%) with biphasic insulin aspart 30. Insulin degludec/insulin aspart achieved the prespecified non-inferiority margin (estimated treatment difference 0.02%; 95% CI -0.12, 0.17). Insulin degludec/insulin aspart was superior in lowering fasting plasma glucose (estimated treatment difference -1.00 mmol/l; 95% CI -1.4, -0.6; P < 0.001) and reducing overall and nocturnal confirmed hypoglycaemia at a similar overall insulin dose compared with biphasic insulin aspart 30. Similar proportions of participants in each arm experienced severe hypoglycaemia. Adverse events were equally distributed. CONCLUSIONS: Consistent with previous findings, insulin degludec/insulin aspart twice daily effectively improved long-term glycaemic control, with superior reductions in FPG, and significantly less overall and nocturnal confirmed hypoglycaemia compared with biphasic insulin aspart 30 in people with Type 2 diabetes who were insulin-naïve.
Subject(s)
Diabetes Mellitus, Type 2/drug therapy , Hyperglycemia/prevention & control , Hypoglycemia/prevention & control , Hypoglycemic Agents/therapeutic use , Insulin, Long-Acting/therapeutic use , Aged , Biphasic Insulins/administration & dosage , Biphasic Insulins/adverse effects , Biphasic Insulins/therapeutic use , Blood Glucose/analysis , Blood Glucose Self-Monitoring , Diabetes Mellitus, Type 2/blood , Drug Administration Schedule , Drug Combinations , Drug Monitoring , Female , Glycated Hemoglobin/analysis , Humans , Hypoglycemia/chemically induced , Hypoglycemia/epidemiology , Hypoglycemia/physiopathology , Hypoglycemic Agents/administration & dosage , Hypoglycemic Agents/adverse effects , Hypoglycemic Agents/chemistry , Insulin Aspart/administration & dosage , Insulin Aspart/adverse effects , Insulin Aspart/therapeutic use , Insulin, Isophane/administration & dosage , Insulin, Isophane/adverse effects , Insulin, Isophane/therapeutic use , Insulin, Long-Acting/administration & dosage , Insulin, Long-Acting/adverse effects , Insulin, Long-Acting/chemistry , Male , Meals , Middle Aged , Risk , Severity of Illness Index , SolubilityABSTRACT
Malignant mesothelioma (MM) remains a highly deadly malignancy with poor treatment option. The MM cells further promote a highly inflammatory microenvironment, which contributes to tumor initiation, development, severity and propagation. We reasoned that the anti-inflammatory actions of mesenchymal stromal cells (MSCs) and further antitumor effects of MSCs engineered to overexpress tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) protein (MSC-TRAIL) would effectively inhibit mesothelioma growth. Using a mouse xenograft model of intraperitoneal human mesothelioma, native mouse (mMSCs) or human (hMSC) MSCs were administered either systemically (intravenously or intraperitoneally) at various times following tumor inoculation. Both mMSCs and hMSCs localized at the sites of MM tumor growth in vivo and decreased local inflammation. Further, a trend towards decrease in tumor burden was observed. Parallel studies of in vitro exposure of nine primary human mesothelioma cell lines to mMSCs or hMSCs demonstrated reduced tumor cell migration. MSC-TRAIL exposure induced apoptosis of TRAIL-sensitive MM cells in vitro, and both mouse and human MSC-TRAIL significantly reduced the inflammatory tumor environment in vivo. Moreover, human MSC-TRAIL administration significantly reduced peritoneal tumor burden in vivo and increased tumor cell apoptosis. These proof-of-concept studies suggest that TRAIL-expressing MSCs may be useful against malignant mesothelioma.
Subject(s)
Gene Expression , Lung Neoplasms/genetics , Lung Neoplasms/therapy , Mesenchymal Stem Cell Transplantation , Mesenchymal Stem Cells/metabolism , Mesothelioma/genetics , Mesothelioma/therapy , TNF-Related Apoptosis-Inducing Ligand/genetics , Animals , Apoptosis/genetics , Cell Line, Tumor , Cell Movement/genetics , Cell Proliferation , Cell- and Tissue-Based Therapy , Cytokines/metabolism , Disease Models, Animal , Humans , Lung Neoplasms/metabolism , Lung Neoplasms/pathology , Male , Mesothelioma/metabolism , Mesothelioma/pathology , Mesothelioma, Malignant , Mice , Mice, SCID , Tumor Burden , Tumor Microenvironment , Xenograft Model Antitumor AssaysABSTRACT
Herpes Simplex virus Type-2 (HSV-2) increases the risk of HIV-1 acquisition, yet the mechanism for this viral pathogen to regulate the susceptibility of the cervicovaginal mucosa to HIV-1 is virtually unknown. Using ex vivo human ectocervical tissue models, we report greater levels of HIV-1 reverse transcription, DNA integration, RNA expression, and virions release in HIV-1/HSV-2 co-infected tissues compared with HIV-1 only infected tissues (P<0.05). Enhanced HIV-1 replication was associated with increased CD4, CCR5, and CD38 transcription (P<0.05) and increased number of CD4(+)/CCR5(+)/CD38(+) T cells in HIV-1/HSV-2 co-infected tissues compared with tissues infected with HIV-1 alone. Tenofovir (TFV) 1% gel, the leading microbicide candidate, demonstrated only partial protection against HIV-1, when applied vaginally before and after sexual intercourse. It is possible that mucosal inflammation, in particular that induced by HSV-2 infection, may have decreased TFV efficacy. HSV-2 upregulated the number of HIV-1-infected cells and elevated the concentration of TFV needed to decrease HIV-1 infection. Similarly, only high concentrations of TFV inhibited HSV-2 replication in HIV-1/HSV-2-infected tissues. Thus, HSV-2 co-infection and mucosal immune cell activation should be taken into consideration when designing preventative strategies for sexual transmission of HIV-1.
Subject(s)
Cervix Uteri/virology , HIV Infections/transmission , HIV Infections/virology , HIV-1/drug effects , HIV-1/physiology , Herpesvirus 2, Human/physiology , Tenofovir/pharmacology , Virus Replication , ADP-ribosyl Cyclase 1/genetics , ADP-ribosyl Cyclase 1/metabolism , Antiviral Agents/pharmacology , Female , Gene Expression Regulation , Humans , Polymerase Chain ReactionABSTRACT
Leucanthoside A, a new allose-containing triterpenoid saponin (1), was isolated from the aerial parts of Cephalaria leucantha L. Its structure was determined by electrospray ionization mass spectrometry and NMR spectroscopy. Complete assignments of the 1H and 13C NMR chemical shifts were achieved by two-dimensional NMR experiments: DQF-COSY, NOESY, TOCSY, HSQC, DINE-HSQC, HMBC, 13C-1H 2D-J-resolved spectroscopy, and 1,1-ADEQUATE.
Subject(s)
Dipsacaceae/chemistry , Saponins/isolation & purification , Triterpenes/isolation & purification , Magnetic Resonance Spectroscopy , Molecular Structure , Plant Components, Aerial/chemistryABSTRACT
Repeated examination of the aerial parts of Hypericum perforatum yielded a new degradation product of hyperforin (1) namely deoxyfurohyperforin A (2), together with the previously identified furohyperforin (3), furoadhyperforin (4), furohyperforin A (5a and 5b), pyrano[7,28-b]hyperforin (6) and 3-methyl-4,6-di(3-methyl-2-butenyl)-2-(2-methyl-1-oxopropyl)-3-(4-methyl-3-pentenyl)-cyclohexanone (7). The antimicrobial activity of the compounds 3, 5a and 5b, 6 and 7 was tested against Staphylococcus aureus, Candida albicans, Bacillus subtilis and Escherichia coli.
Subject(s)
Anti-Infective Agents/pharmacology , Bridged-Ring Compounds/pharmacology , Candida albicans/drug effects , Gram-Negative Bacteria/drug effects , Gram-Positive Bacteria/drug effects , Hypericum , Phytotherapy , Plant Extracts/pharmacology , Terpenes/pharmacology , Anti-Bacterial Agents , Anti-Infective Agents/therapeutic use , Bacillus subtilis/drug effects , Bridged Bicyclo Compounds , Bridged-Ring Compounds/therapeutic use , Escherichia coli/drug effects , Humans , Microbial Sensitivity Tests , Phloroglucinol/analogs & derivatives , Plant Extracts/therapeutic use , Staphylococcus aureus/drug effects , Terpenes/chemistry , Terpenes/therapeutic useABSTRACT
Pulchellin E (1) and gaillardin (2) were isolated from the aerial parts of Inula oculus-christi, along with the flavone hispidulin. The 13C-NMR chemical shifts of 1 and 2 are reported.
Subject(s)
Inula , Lactones/chemistry , Phytotherapy , Plant Extracts/chemistry , Sesquiterpenes/chemistry , Humans , Plant Components, AerialABSTRACT
Cell survival is critically dependent on the preservation of cellular bioenergetics. However, the metabolic mechanisms that confer resistance to injury are poorly understood. Phosphotransfer reactions integrate ATP-consuming with ATP-producing processes and could thereby contribute to the generation of a protective phenotype. Here, we used ischemic preconditioning to induce a stress-tolerant state and (18)O-assisted (31)P nuclear magnetic resonance spectroscopy to capture intracellular phosphotransfer dynamics. Preconditioning of isolated perfused hearts triggered a redistribution in phosphotransfer flux with significant increase in creatine kinase and glycolytic rates. High energy phosphoryl fluxes through creatine kinase, adenylate kinase, and glycolysis in preconditioned hearts correlated tightly with post-ischemic functional recovery. This was associated with enhanced metabolite exchange between subcellular compartments, manifested by augmented transfer of inorganic phosphate from cellular ATPases to mitochondrial ATP synthase. Preconditioning-induced energetic remodeling protected cellular ATP synthesis and ATP consumption, improving contractile performance following ischemia-reperfusion insult. Thus, the plasticity of phosphotransfer networks contributes to the effective functioning of the cellular energetic system, providing a mechanism for increased tolerance toward injury.
Subject(s)
Adenosine Triphosphate/metabolism , Oxygen/metabolism , Phosphates/chemistry , Adenylate Kinase/metabolism , Animals , Binding Sites , Creatine Kinase/metabolism , Glycolysis , Heart/physiology , Ischemia , Ischemic Preconditioning , Kinetics , Magnetic Resonance Spectroscopy , Male , Models, Chemical , Perfusion , Protein Binding , Rats , Rats, Sprague-Dawley , Stress, PhysiologicalABSTRACT
To determine the extent and microanatomical distribution of extramyocellular adipocytes associated with skeletal muscle, histological, biochemical, nuclear magnetic resonance proton spectroscopic and microcomputed tomography techniques were employed to analyze skeletal muscle samples from lean and obese Sprague-Dawley rats. Significant amounts of extramyocellular adipocytes were found on the exterior surface of rat gastrocnemius, soleus, and tibialis anterior muscles. The triglyceride content of these exterior adipocytes in these muscle groups was 2- to 3-fold greater than that of the respective intramyocellular triglyceride pool (P = 0.01). Thus, the exterior adipocytes associated with skeletal muscle samples are an abundant source of extramyocellular fat potentially contaminating the intramyocellular triglyceride pool if not carefully and completely removed. On the other hand, no adipocytes were found in the interfascicular space (between muscle bundles) or the intrafascicular space (between muscle fibers) in any of the three rat muscles. The feasibility of and procedures for removing extramyocellular fat by microdissection techniques to obtain pure muscle sample were also evaluated. Complete removal of the extramyocellular adipocytes from rat skeletal muscle, using microdissection with a stereo microscope, was found to be practical and effective. It is concluded that pure muscle samples free of contamination by extramyocellular fat can be obtained, but only if microdissection techniques are utilized.
Subject(s)
Adipocytes/chemistry , Muscle, Skeletal/chemistry , Muscle, Skeletal/cytology , Triglycerides/chemistry , Adipocytes/cytology , Animals , Magnetic Resonance Spectroscopy , Rats , Rats, Sprague-Dawley , Tomography, X-Ray ComputedABSTRACT
In the reaction of trans-[CoCl2(en)2]+ with L-tyrosine all six theoretically possible diastereomers of the (1,2-diaminoethane)bis(L-tyrosinato)cobalt(III) complex were formed. The following five were isolated: gamma-trans(O); and gamma- and delta-C2-cis(O) and gamma- and delta-C1-cis(O) diastereomers, while the delta-trans(O) diastereomer was only detected in the corresponding eluate. Separation of the obtained diastereomers was performed by chromatography on a Dowex 1 x 4 column. Characterization of the isolated diastereomers was carried out by means of elemental analysis, electronic absorption, circular dichroic, 1H and 13C NMR spectra, and by x-ray crystal structure analysis in the case of the delta-C1-cis(O) diastereomer. We established the general rule of preference of diasteromers formation in complexes of [Co(L-aa)2diamine]+ (L-aa = L-amino acid anion; diamine = 1,2-diaminoethane or 1,3-diaminopropane) type.
ABSTRACT
Rapid exchange of high energy carrying molecules between intracellular compartments is essential in sustaining cellular energetic homeostasis. Adenylate kinase (AK)-catalyzed transfer of adenine nucleotide beta- and gamma-phosphoryls has been implicated in intracellular energy communication and nucleotide metabolism. To demonstrate the significance of this reaction in cardiac energetics, phosphotransfer dynamics were determined by [(18)O]phosphoryl oxygen analysis using( 31)P NMR and mass spectrometry. In hearts with a null mutation of the AK1 gene, which encodes the major AK isoform, total AK activity and beta-phosphoryl transfer was reduced by 94% and 36%, respectively. This was associated with up-regulation of phosphoryl flux through remaining minor AK isoforms and the glycolytic phosphotransfer enzyme, 3-phosphoglycerate kinase. In the absence of metabolic stress, deletion of AK1 did not translate into gross abnormalities in nucleotide levels, gamma-ATP turnover rate or creatine kinase-catalyzed phosphotransfer. However, under hypoxia AK1-deficient hearts, compared with the wild type, had a blunted AK-catalyzed phosphotransfer response, lowered intracellular ATP levels, increased P(i)/ATP ratio, and suppressed generation of adenosine. Thus, although lack of AK1 phosphotransfer can be compensated in the absence of metabolic challenge, under hypoxia AK1-knockout hearts display compromised energetics and impaired cardioprotective signaling. This study, therefore, provides first direct evidence that AK1 is essential in maintaining myocardial energetic homeostasis, in particular under metabolic stress.
Subject(s)
Adenylate Kinase/physiology , Energy Metabolism , Myocardium/metabolism , Adenosine Triphosphate/analysis , Adenylate Kinase/genetics , Animals , Homeostasis , Mice , Mice, KnockoutABSTRACT
A new germacranolide, (E)-1alpha, 10beta-epoxy-3beta-acetoxy-6alpha-hydroxygermacra-4,11 (13)-dien-12,8alpha-olide, together with nine new highly oxygenated guaiadien-12,6alpha-olides of anthemolide, and cumambrin type were identified in the repeated examination of the aerial parts of the flowering Anthemis carpatica. In addition, six known guaianolides belonging to the same groups, also isolated previously from A. carpatica, along with two guaianolides, 2beta-hydroxyepiligustrin and cumambrin B, not found before in this species, were isolated this time.
Subject(s)
Asteraceae/chemistry , Lactones/chemistry , Plants, Medicinal/chemistry , Sesquiterpenes/chemistry , Lactones/isolation & purification , Magnetic Resonance Spectroscopy , Sesquiterpenes/isolation & purificationABSTRACT
A method for quantitative determination of magnetization exchange rate constants (cross-relaxation and chemical exchange) from a series of two-dimensional exchange spectra is presented. The method, the least error matrix analysis (LEMA), combines a series of full matrix calculations at different mixing times in a least-squares manner. LEMA embodies the principal advantages of full-relaxation matrix analysis (FMA) and initial rate buildup (BU) analysis. Like FMA, it takes into account all the relations among the spectral matrix elements and in analogy to BU makes use of their time evolution. By means of calculations, simulations, and experiments, we have shown that LEMA provides the dynamic matrix from a given set of experimental data with errors that are smaller than in either FMA or BU calculations.
ABSTRACT
A single water molecule (w135), buried within the structure of rat intestinal fatty acid binding protein (I-FABP), is investigated by NMR, molecular dynamics simulations, and analysis of known crystal structures. An ordered water molecule was found in structurally analogous position in 24 crystal structures of nine different members of the family of fatty acid binding proteins. There is a remarkable conservation of the local structure near the w135 binding site among different proteins from this family. NMR cross-relaxation measurements imply that w135 is present in the I-FABP:ANS (1-sulfonato-8-(1')anilinonaphthalene) complex in solution with the residence time of >300 ps. Mean-square positional fluctuations of w135 oxygen observed in MD simulations (0.18 and 0.13 A2) are comparable in magnitude to fluctuations exhibited by the backbone atoms and result from highly constrained binding pocket as revealed by Voronoi volumes (averages of 27.0 +/- 1.8 A3 and 24.7 +/- 2.2 A3 for the two simulations). Escape of w135 from its binding pocket was observed only in one MD simulation. The escape process was initiated by interactions with external water molecules and was accompanied by large deformations in beta-strands D and E. Immediately before the release, w135 assumed three distinct states that differ in hydrogen bonding topology and persisted for about 15 ps each. Computer simulations suggest that escape of w135 from the I-FABP matrix is primarily determined by conformational fluctuations of the protein backbone and interactions with external water molecules.
Subject(s)
Carrier Proteins/chemistry , Fatty Acids/chemistry , Myelin P2 Protein/chemistry , Neoplasm Proteins , Nerve Tissue Proteins , Water/chemistry , Animals , Binding Sites , Crystallography, X-Ray , Fatty Acid-Binding Protein 7 , Fatty Acid-Binding Proteins , Hydrogen Bonding , Magnetic Resonance Spectroscopy , Models, Molecular , RatsABSTRACT
We propose a method to improve the sensitivity in volume selective detection based on the CARVE excitation sequence (I. Sersa and S. Macura, J. Magn. Reson. 135, 466-477 (1998)) which consists of signal acquisition with constant tip angle excitation and a short phase-encoding gradient pulse. Volume selectivity is achieved using the weighted average of a number of scans whose weights and gradient steps are determined by the shape of the excitation profile. The method is particularly useful for broadband volume selective detection of insensitive spins where the volume selection can be merged with the standard signal averaging process, without compromising the excitation bandwidth or sensitivity.
Subject(s)
Magnetic Resonance Spectroscopy/methodsABSTRACT
Heterogeneous fluorescence intensity decays of tryptophan in proteins are often rationalized using a model which proposes that different rotameric states of the indole alanyl side-chain are responsible for the observed fluorescence lifetime heterogeneity. We present here the study of a mutant of carp parvalbumin bearing a single tryptophan residue at position 102 (F102W) whose fluorescence intensity decay is heterogeneous and assess the applicability of a rotamer model to describe the fluorescence decay data. We have determined the solution structure of F102W in the calcium ligated state using multi-dimensional nuclear magnetic resonance (NMR) and have used the minimum perturbation mapping technique to explore the possible existence of multiple conformations of the indole moiety of Trp102 of F102W and, for comparison, Trp48 of holo-azurin. The maps for parvalbumin suggest two potential conformations of the indole side-chain. The high energy barrier for rotational isomerization between these conformers implies that interwell rotation would occur on time-scales of milliseconds or greater and suggests a rotamer basis for the heterogeneous fluorescence. However, the absence of alternate Trp102 conformers in the NMR data (to within 3 % of the dominant species) suggests that the heterogeneous fluorescence of Trp102 may arise from mechanisms independent of rotameric states of the Trp side-chain. The map for holo-azurin has only one conformation, and suggests a rotamer model may not be required to explain its heterogeneous fluorescence intensity decay. The backbone and Trp102 side-chain dynamics at 30 degrees C of F102W has been characterized based on an analysis of (15)N NMR relaxation data which we have interpreted using the Lipari-Szabo formalism. High order parameter (S(2)) values were obtained for both the helical and loop regions. Additionally, the S(2) values imply that the calcium binding CD and EF loops are not strictly equivalent. The S(2) value for the indole side-chain of Trp102 obtained from the fluorescence, NMR relaxation and minimum perturbation data are consistent with a Trp moiety whose motion is restricted.
Subject(s)
Carps , Mutation/genetics , Parvalbumins/chemistry , Parvalbumins/metabolism , Tryptophan/genetics , Tryptophan/metabolism , Amino Acid Substitution/genetics , Animals , Azurin/chemistry , Azurin/metabolism , Binding Sites , Calcium/metabolism , EF Hand Motifs , Fluorescence , Fluorescence Polarization , Isomerism , Kinetics , Models, Molecular , Nuclear Magnetic Resonance, Biomolecular , Parvalbumins/genetics , Protein Structure, Secondary , Pseudomonas aeruginosa/chemistry , Rotation , Solutions , Thermodynamics , Tryptophan/chemistryABSTRACT
Glucosamine (GlcN) modulates fluoropyrimidine metabolism and enhances cytotoxicity of 5-fluorouridine (FUrd), but not of 5-fluorouracil (FUra), in human tumor models. To elucidate the underlying metabolic differences between FUra and FUrd, by the use of 19F and 31P NMR spectroscopy we studied these drugs in multicell tumor spheroids (MTS) formed by human colon carcinoma cells HT-29. This experimental system allowed detailed kinetic measurements of anabolic intracellular phosphates and fluorophosphates over periods of up to 2 days. Time-dependent NMR data were reduced and interpreted by the use of nonlinear compartmental models which yielded numerical values for the empirical rate constants characterizing mass transfer among the compartments. An analysis of these rate constants indicated qualitative and quantitative differences in the metabolism of FUra and FUrd and in the effects of GlcN on these drugs. The enhanced generation of FUDP-hexoses was a predicted effect of GlcN, but inhibited formation of fluorouridine diphosphates and fluorouridine triphosphates in FUra-treated MTS, and the magnitude of stimulation of fluoropyrimidine incorporation into macromolecules in FUrd-treated MTS were not predicted.
Subject(s)
Colonic Neoplasms/metabolism , Fluorouracil/metabolism , Glucosamine/metabolism , Uridine/analogs & derivatives , Body Fluid Compartments/physiology , Glucosamine/chemistry , Humans , Kinetics , Magnetic Resonance Spectroscopy , Models, Biological , Nonlinear Dynamics , Phosphates/metabolism , Spheroids, Cellular/metabolism , Uridine/metabolismABSTRACT
Four flavones (1-4) and nine sesquiterpene lactones (5-13), one of them (5) a new compound, were isolated from the aerial parts of Achillea atrata L. subsp. multifida. Although the crude extract demonstrated in vitro inhibitory activity against Candida albicans and Bacillus subtilis, all isolated flavones were active against B. subtilis. Flavones 1, 2, and 3 were also active against C. albicans, while 1 and 3 exhibited activity against E. coli, as well. None of the tested lactones (7, 9, 12, and 13) showed any antimicrobial activity.