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Frontiers in Pediatrics 2023The deuterium dose-to-mother (DTM) method measures the human milk intake of breastfed children. Recently, the use of this method has been expanded to classify babies...
BACKGROUND
The deuterium dose-to-mother (DTM) method measures the human milk intake of breastfed children. Recently, the use of this method has been expanded to classify babies objectively as exclusively breast fed (EBF) or not (non-EBF) based on quantification of non-milk oral water intake (NMOI). However, the calculation of NMOI estimates involves atmospheric temperature and humidity.
OBJECTIVE
To evaluate the effects of atmospheric temperature and humidity on NMOI calculation and the classification of exclusive breastfeeding.
METHODS
The effect of indoor temperature and relative humidity on NMOI and the estimated prevalence of non-EBF were examined in two existing data sets of DTM in children by varying temperature in the range of 15 to 35°C and relative humidity in the range of 20 to 80% representing the maximum span of indoor conditions expected. Population-level estimates of NMOI distributions were derived using the rstan package for R v2.21.2.
RESULTS
The NMOI decreased at a rate of -1.15 g/day per °C increase and at a rate of -1.01 g/day per percent increase in relative humidity; this was due to variations in non-oral water intake from the atmosphere, a component of the calculation of NMOI, which is dependent on temperature and humidity. For the various locations considered, the mean calculated NMOI varied between 24.6 and 53.3 g/day using the same input data. In the mixed-fed sample of babies, the prevalence of non-EBF based on the earlier defined NMOI cut-off of 86.6 g/day was reduced by 19% when relative humidity was increased by 60%.
CONCLUSIONS
Atmospheric conditions are essential factors in the computation of NMOI, used in the objective classification of babies as exclusively breast fed or not, and should be considered when the DTM method is used to classify exclusive breastfeeding.
PubMed: 38034831
DOI: 10.3389/fped.2023.1188811 -
The Journal of Biological Chemistry Jan 2024Neuronal nitric oxide synthase (nNOS) is a homodimeric cytochrome P450-like enzyme that catalyzes the conversion of L-arginine to nitric oxide in the presence of NADPH...
Neuronal nitric oxide synthase (nNOS) is a homodimeric cytochrome P450-like enzyme that catalyzes the conversion of L-arginine to nitric oxide in the presence of NADPH and molecular oxygen. The binding of calmodulin (CaM) to a linker region between the FAD/FMN-containing reductase domain, and the heme-containing oxygenase domain is needed for electron transfer reactions, reduction of the heme, and NO synthesis. Due to the dynamic nature of the reductase domain and low resolution of available full-length structures, the exact conformation of the CaM-bound active complex during heme reduction is still unresolved. Interestingly, hydrogen-deuterium exchange and mass spectrometry studies revealed interactions of the FMN domain and CaM with the oxygenase domain for iNOS, but not nNOS. This finding prompted us to utilize covalent crosslinking and mass spectrometry to clarify interactions of CaM with nNOS. Specifically, MS-cleavable bifunctional crosslinker disuccinimidyl dibutyric urea was used to identify thirteen unique crosslinks between CaM and nNOS as well as 61 crosslinks within the nNOS. The crosslinks provided evidence for CaM interaction with the oxygenase and reductase domain residues as well as interactions of the FMN domain with the oxygenase dimer. Cryo-EM studies, which gave a high-resolution model of the oxygenase domain, along with crosslink-guided docking provided a model of nNOS that brings the FMN within 15 Å of the heme in support for a more compact conformation than previously observed. These studies also point to the utility of covalent crosslinking and mass spectrometry in capturing transient dynamic conformations that may not be captured by hydrogen-deuterium exchange and mass spectrometry experiments.
Topics: Calmodulin; Heme; Mass Spectrometry; Nitric Oxide Synthase Type I; Oxygenases; Cross-Linking Reagents; Calcium; Models, Molecular; Protein Structure, Quaternary; Protein Binding; Cryoelectron Microscopy
PubMed: 37979917
DOI: 10.1016/j.jbc.2023.105464 -
BioRxiv : the Preprint Server For... Nov 2023Production of soluble proteins is essential for structure/function studies, however, this usually requires milligram amounts of protein, which can be difficult to obtain...
Production of soluble proteins is essential for structure/function studies, however, this usually requires milligram amounts of protein, which can be difficult to obtain with traditional expression systems. Recently, the Gram-negative bacterium appeared as a novel and alternative host platform for production of proteins in high yields. Here, we used a commercial strain derived from (Vmax X2) to produce soluble bacterial and fungal proteins in milligram scale, which we struggled to achieve in . These proteins include the cholera toxin (CT) and -acetyl glucosamine binding protein A (GbpA) from , the heat-labile enterotoxin (LT) from and the fungal nematotoxin CCTX2 from . CT, GbpA and LT are secreted by the Type II secretion system in their natural hosts. When these three proteins were produced in Vmax, they were also secreted, and could be recovered from the growth media. This simplified the downstream purification procedure and resulted in considerably higher protein yields compared to production in (6- to 26-fold increase). We also tested Vmax for protein deuteration using deuterated minimal media with deuterium oxide as solvent, and achieved a 3-fold increase in yield compared to the equivalent protocol in . This is good news since isotopic labeling is expensive and often ineffective, but represents a necessary prerequisite for some structural techniques. Thus, Vmax represents a promising host for production of challenging expression targets and for protein deuteration in amounts suitable for structural biology studies.
PubMed: 37961550
DOI: 10.1101/2023.11.03.565449 -
Analytical Chemistry Nov 2023In drug research and development, knowledge of the precise structure of an active ingredient is crucial. However, it is equally important to know the water content of...
In drug research and development, knowledge of the precise structure of an active ingredient is crucial. However, it is equally important to know the water content of the drug molecule, particularly the number of crystal waters present in its structure. Such knowledge ensures the avoidance of drug dosage and formulation errors since the number of water molecules affects the physicochemical and pharmaceutical properties of the molecule. Several methods have been used for crystal water measurements of organic compounds, of which thermogravimetry and crystallography may be the most common ones. To the best of our knowledge, solution-state NMR spectroscopy has not been used for crystal water determination in deuterium oxide. Quantitative NMR (qNMR) method will be presented in the paper with a comparison of single-crystal X-ray diffraction and thermogravimetric analysis results. The qNMR method for water content measurement is straightforward, reproducible, and accurate, including measurement of H NMR spectrum before and after the addition of the analyte compound, and the result can be calculated after integration of the reference compound, analyte, and HDO signals using the given equation. In practical terms, there is no need for weighing the samples under study, which makes it simple and is a clear advantage to the current determination methods. In addition, the crystal structures of two model bisphosphonates used herein are reported: that of monopotassium etidronate dihydrate and monosodium zoledronate trihydrate.
PubMed: 37923567
DOI: 10.1021/acs.analchem.3c03689 -
Frontiers in Nutrition 2023Neurologically impaired (NI) children are at risk of malnutrition, which consequently impacts their health and quality of life. Accurate nutrition assessment is an...
Measurement of body composition by deuterium oxide dilution technique and development of a predictive equation for body fat mass among severe neurologically impaired children.
INTRODUCTION
Neurologically impaired (NI) children are at risk of malnutrition, which consequently impacts their health and quality of life. Accurate nutrition assessment is an important step in guiding appropriate nutrition support. Conventional anthropometric measurements among NI children have some limitations. Determining body composition requires more complex equipment, which is not routinely performed. This study was conducted to evaluate the association between anthropometric parameters and body composition assessed using the deuterium dilution technique (DDT) in NI children.
METHODS
A cross-sectional study enrolled severe NI children aged 1-20 years who received home enteral nutrition for at least 3 months. Weight, length, and 4-site skinfold thickness were measured. Body composition was determined using DDT following the International Atomic Energy Agency (IAEA) protocol.
RESULTS
A total of 37 NI children (56.76% male, median age 7.2 years) were enrolled. The prevalence of underweight, stunting, and overweight were 22, 38, and 35%, respectively. Body composition analysis showed the mean (SD) of total body water (TBW) and fat mass (FM) were 10.52 (4.51) kg and 9.51 (6.04) kg, respectively. Multivariate GLM analysis showed that the factors associated with FM were age (β = 0.07 [0.05,0.08]; < 0.001), body mass index (BMI) (β = 0.82 [0.52, 1.12]; < 0.001), biceps skinfold thickness (BSF) (β = 0.49 [0.23,0.75]; = 0.001), and subscapular skinfold thickness (SSF) (β = -0.24 [-0.46,0.03]; = 0.030). A predictive equation for FM was constructed.
CONCLUSION
A high prevalence of malnutrition was found among severe NI children despite enteral nutrition support. Our findings showed that age, BMI, BSF, and SSF were associated with FM. The predictive equation of FM was proposed and needed to be further validated and applied to clinical practice.
PubMed: 37920288
DOI: 10.3389/fnut.2023.1162956 -
International Journal of Molecular... Oct 2023Mass spectrometry has been an essential technique for the investigation of the metabolic pathways of living organisms since its appearance at the beginning of the 20th...
Mass spectrometry has been an essential technique for the investigation of the metabolic pathways of living organisms since its appearance at the beginning of the 20th century. Due to its capability to resolve isotopically labeled species, it can be applied together with stable isotope tracers to reveal the transformation of particular biologically relevant molecules. However, low-resolution techniques, which were used for decades, had limited capabilities for untargeted metabolomics, especially when a large number of compounds are labelled simultaneously. Such untargeted studies may provide new information about metabolism and can be performed with high-resolution mass spectrometry. Here, we demonstrate the capabilities of high-resolution mass spectrometry to obtain insights on the metabolism of a model plant, , germinated in DO and HO-enriched media. In particular, we demonstrated that in vivo labeling with heavy water helps to identify if a compound is being synthesized at a particular stage of germination or if it originates from seed content, and tandem mass spectrometry allows us to highlight the substructures with incorporated isotope labels. Additionally, we found in vivo labeling useful to distinguish between isomeric compounds with identical fragmentation patterns due to the differences in their formation rates that can be compared by the extent of heavy atom incorporation.
Topics: Deuterium Oxide; Isotope Labeling; Metabolomics; Tandem Mass Spectrometry; Plants; Isotopes
PubMed: 37895078
DOI: 10.3390/ijms242015396 -
GeroScience Apr 2024Age-associated declines in aerobic capacity promote the development of various metabolic diseases. In rats selectively bred for high/low intrinsic aerobic capacity,...
Age-associated declines in aerobic capacity promote the development of various metabolic diseases. In rats selectively bred for high/low intrinsic aerobic capacity, greater aerobic capacity reduces susceptibility to metabolic disease while increasing longevity. However, little remains known how intrinsic aerobic capacity protects against metabolic disease, particularly with aging. Here, we tested the effects of aging and intrinsic aerobic capacity on systemic energy expenditure, metabolic flexibility and mitochondrial protein synthesis rates using 24-month-old low-capacity (LCR) or high-capacity runner (HCR) rats. Rats were fed low-fat diet (LFD) or high-fat diet (HFD) for eight weeks, with energy expenditure (EE) and metabolic flexibility assessed utilizing indirect calorimetry during a 48 h fast/re-feeding metabolic challenge. Deuterium oxide (D2O) labeling was used to assess mitochondrial protein fraction synthesis rates (FSR) over a 7-day period. HCR rats possessed greater EE during the metabolic challenge. Interestingly, HFD induced changes in respiratory exchange ratio (RER) in male and female rats, while HCR female rat RER was largely unaffected by diet. In addition, analysis of protein FSR in skeletal muscle, brain, and liver mitochondria showed tissue-specific adaptations between HCR and LCR rats. While brain and liver protein FSR were altered by aerobic capacity and diet, these effects were less apparent in skeletal muscle. Overall, we provide evidence that greater aerobic capacity promotes elevated EE in an aged state, while also regulating metabolic flexibility in a sex-dependent manner. Modulation of mitochondrial protein FSR by aerobic capacity is tissue-specific with aging, likely due to differential energetic requirements by each tissue.
Topics: Rats; Male; Female; Animals; Energy Metabolism; Liver; Diet, High-Fat; Metabolic Diseases; Mitochondrial Proteins
PubMed: 37880490
DOI: 10.1007/s11357-023-00985-1 -
International Journal of Molecular... Sep 2023In the heavy petroleum industry, the development of efficient demulsifiers for the effective breaking of interfacially active asphaltenes (IAA)-stabilized water-in-heavy...
In the heavy petroleum industry, the development of efficient demulsifiers for the effective breaking of interfacially active asphaltenes (IAA)-stabilized water-in-heavy oil (W/HO) emulsions is a highly attractive but challenging goal. Herein, a novel nitrogen and oxygen containing demulsifier (JXGZ) with strong hydrogen bonding has been successfully synthesized through combining esterification, polymerization and amidation. Bottle tests indicated that JXGZ is effectual in quickly demulsifying the IAA-stabilized W/HO emulsions; complete dehydration (100%) to the emulsions could be achieved in 4 min at 55 °C using 400 ppm of JXGZ. In addition, the effects of demulsifier concentration, temperature and time on the demulsification performance of JXGZ are systematically analyzed. Demulsification mechanisms reveal that the excellent demulsification performance of JXGZ is attributed to the strong hydrogen bonding between JXGZ and water molecules (dual swords synergistic effect under hydrogen bond reconstruction). The interaction of the "dual swords synergistic effect" generated by two types of hydrogen bonds can quickly break the non-covalent interaction force (π-π stacking, Van der Waals force, hydrogen bonds) of IAA at the heavy oil-water interface, quickly promote the aggregation and coalescence of water molecules and finally achieve the demulsification of W/HO emulsions. These findings indicate that the JXGZ demulsifier shows engineering application prospects in the demulsification of heavy oil-water emulsions, and this work provides the key information for developing more efficient chemical demulsifiers suitable for large-scale industrial applications.
Topics: Emulsions; Hydrogen Bonding; Water; Petroleum; Deuterium Oxide
PubMed: 37834251
DOI: 10.3390/ijms241914805 -
Nano Letters Oct 2023Proteins are versatile, self-assembling nanoelectronic components, but their hopping conductivity is expected to be influenced by solvent fluctuations. The role of the...
Proteins are versatile, self-assembling nanoelectronic components, but their hopping conductivity is expected to be influenced by solvent fluctuations. The role of the solvent was investigated by measuring the single molecule conductance of several proteins in both HO and DO. The conductance of a homologous series of protein wires decreases more rapidly with length in DO, indicating a 6-fold decrease in carrier diffusion constant relative to the same protein in HO. The effect was found to depend on the specific aromatic amino acid composition. A tryptophan zipper protein showed a decrease in conductance similar to that of the protein wires, whereas a phenylalanine zipper protein was insensitive to solvent changes. Tryptophan contains an indole amine, whereas the phenylalanine aromatic ring has no exchangeable protons, so the effect of heavy water on conductance is a consequence of specific D- or H-interactions with the aromatic residues.
Topics: Deuterium Oxide; Deuterium; Tryptophan; Proteins; Phenylalanine; Protons; Solvents
PubMed: 37772726
DOI: 10.1021/acs.nanolett.3c02263 -
Gut Microbes Dec 2023Maternal secretor status has been shown to be associated with the presence of specific fucosylated human milk oligosaccharides (HMOs), and the impact of maternal...
Maternal secretor status has been shown to be associated with the presence of specific fucosylated human milk oligosaccharides (HMOs), and the impact of maternal secretor status on infant gut microbiota measured through 16s sequencing has previously been reported. None of those studies have confirmed exclusive breastfeeding nor investigated the impact of maternal secretor status on gut microbial fermentation products. The present study focused on exclusively breastfed (EBF) Indonesian infants, with exclusive breastfeeding validated through the stable isotope deuterium oxide dose-to-mother (DTM) technique, and the impact of maternal secretor status on the infant fecal microbiome and metabolome. Maternal secretor status did not alter the within-community (alpha) diversity, between-community (beta) diversity, or the relative abundance of bacterial taxa at the genus level. However, infants fed milk from secretor (Se+) mothers exhibited a lower level of fecal succinate, amino acids and their derivatives, and a higher level of 1,2-propanediol when compared to infants fed milk from non-secretor (Se-) mothers. Interestingly, for infants consuming milk from Se+ mothers, there was a correlation between the relative abundance of and , and between each of these genera and fecal metabolites that was not observed in infants receiving milk from Se- mothers. Our findings indicate that the secretor status of the mother impacts the gut microbiome of the exclusively breastfed infant.
Topics: Infant; Female; Humans; Breast Feeding; Gastrointestinal Microbiome; Milk, Human; Microbiota; Oligosaccharides; Metabolome
PubMed: 37741856
DOI: 10.1080/19490976.2023.2257273