Purpose To develop and evaluate an automated segmentation method for accurate quantification of abdominal adipose tissue (AAT) depots (superficial subcutaneous adipose tissue [SSAT], deep subcutaneous adipose tissue [DSAT], and visceral adipose tissue [VAT]) in neonates and young children. Materials and Methods This was a secondary analysis of prospectively collected data, which used abdominal MRI data from Growing Up in Singapore Towards healthy Outcomes, or GUSTO, a longitudinal mother-offspring cohort, to train and evaluate a convolutional neural network for volumetric AAT segmentation. The data comprised imaging volumes of 333 neonates obtained at early infancy (age ≤2 weeks, 180 male neonates) and 755 children aged either 4.5 years (n = 316, 150 male children) or 6 years (n = 439, 219 male children). The network was trained on images of 761 randomly selected volumes (neonates and children combined) and evaluated on 100 neonatal volumes and 227 child volumes by using 10-fold validation. Automated segmentations were compared with expert-generated manual segmentation. Segmentation performance was assessed using Dice scores. Results When the model was tested on the test datasets across the 10 folds, the model had strong agreement with the ground truth for all testing sets, with mean Dice similarity scores for SSAT, DSAT, and VAT, respectively, of 0.960, 0.909, and 0.872 in neonates and 0.944, 0.851, and 0.960 in children. The model generalized well to different body sizes and ages and to all abdominal levels. Conclusion The proposed segmentation approach provided accurate automated volumetric assessment of AAT compartments on MR images of neonates and children.Keywords Pediatrics, Deep Learning, Convolutional Neural Networks, Water-Fat MRI, Image Segmentation, Deep and Superficial Subcutaneous Adipose Tissue, Visceral Adipose TissueClinical trial registration no. NCT01174875 Supplemental material is available for this article. © RSNA, 2021.
Recently there has been a significant increase in the amount and frequency of seaweed blooms of the holopelagic brown macroalgae Sargassum fluitans and natans (hereafter Sargassum) in the Atlantic Ocean. These blooms impose a major burden on residents (e.g. rotting beached Sargassum, unpleasant odor, toxic gases), the local economy of countries with affected coast lines (e.g. impacting tourism and aquaculture, costs for remediation), and have a significant impact on the environment (e.g. beaches and coastal areas) and local marine wildlife. Here we present a Techno-Economic Analysis to demonstrate how this burden can be turned into an economic, social and environmental asset. The suggested process involves sustainable ship-based harvesting of excess biomass (up to 6.3 MT.year(-1)) and using hydrothermal liquefaction (HTL) and established fuel refining processes to deliver renewable liquid fuels. Sea-based harvesting of Sargassum addresses the primary cost impediment for algae-based renewable fuel production, reducing capital and operating costs by 78% and 66% respectively compared with currently modelled land-based microalgae renewable fuel production processes. The modelled approach charts a path to cost competitive renewable fuels that reduce CO2 emissions while mitigating the economic, social and environmental problems caused by these large Sargassum algae blooms. The financial analysis of the process yielded an Internal Rate of Return (IRR) between 2.4% and 28.1% based on the scenarios analyzed. The process could generate up to 8500 bbl of crude oil per day profitably at US$43 bbl(-1) (10% IRR), equivalent to 470 ML of diesel or jet fuel per year as well as biofertilizers and recycled nutrients, employ around 200 direct personnel and create up to 1000 indirect jobs.
Background: Lympho-epithelial Kazal-type-related inhibitor (LEKTI) is a 15-domain serine proteinase inhibitor, parts of which have first been isolated from human blood filtrate. It is encoded by the gene SPINK5. In the past, different groups reported antiviral activities of certain serine proteinase inhibitors, such as mucus proteinase inhibitor and alpha1-proteinase inhibitor. The purpose of this study was to test two representative domains of the proteinase inhibitor LEKTI for anti-HIV activities.Methods: LEKTI domains 6 and 15 were recombinantly produced in E.coli. To test their inhibitory activity against HIV infection, the reporter cell line P4-R5 MAGI carrying an HIV-inducible reporter gene was infected by a CCR5-tropic HIV strain in the presence of different inhibitor concentrations. After three days, infection rates were determined by quantifying beta-galactosidase activities using the Galacto-Light Plus (TM) beta-Galactosidase Reporter Gene Assay.Results: In contrast to LEKTI domain 6, LEKTI domain 15 suppressed HIV-induced reporter gene activities with an IC50 value of approximately 29 mu M.Conclusion: LEKTI domain 15 represents an inhibitor of HIV infection.
REASONS FOR PERFORMING STUDY:NMR-metabonomics is an unbiased evaluation method, which allows to comprehensively study changes of the equine metabolic profile in early time point laminitis. This might give insight into the early stages of disease development.OBJECTIVES:To detect hitherto unknown changes in blood metabolites during the development of oligofructose-induced laminitis by comparing pre- and post induction blood samples.METHODS:Prior to laminitis induction blood was sampled to establish control values. Post oligofructose administration (POA) blood was collected every 3 h for 24 h. One-dimensional (1) H-NMR spectra of the blood plasma were statistically analysed.RESULTS:NMR resonances of >20 metabolites were identified using this technique. Already known changes (e.g. lactate concentrations) were confirmed using this method. Interestingly, oligofructose, a carbohydrate usually considered indigestible in the small intestine, or derivatives of oligofructose, was detected in plasma. Horses also showed increased phosphatidylcholine and/or low density lipoprotein levels POA, indicating a change in blood lipid composition. An increase in phosphatidylcholine is consistent with the breakdown of the mucosal layer of the large intestine and increased permeability of the gut.CONCLUSION:Due to the nontargeted approach of metabonomics, new unexpected changes can be identified, in this case the hitherto unknown oligofructose uptake through the mucosal wall and the phospholipid changes.POTENTIAL RELEVANCE:Metabolic changes in disease can be observed using NMR metabonomics. Oligofructose is used in feedstuffs and transport mechanisms through the mucosa should be studied. Phospholipids could point to a compromise of the intestinal wall during laminitis development.
Retrocyclins are circular mini-defensins with significant potential as agents against human immunodeficiency virus, influenza A, and herpes simplex virus. Retrocyclins bind carbohydrate-containing surface molecules such as gp120 and CD4 with high affinity (Kd, 10-100 nM), promoting their localization on cell membranes. The structural features important for activity have yet to be fully elucidated, but here, we have determined the first three-dimensional structure of a retrocyclin, namely, one of the most potent forms, retrocyclin-2. In the presence of SDS micelles, a well-defined beta-hairpin braced by three disulfide bonds that defines the cystine ladder motif is present. By contrast, a well-defined structure could not be determined in aqueous solution, suggesting that the presence of SDS micelles stabilizes the extended conformation of retrocyclin-2. Translational diffusion measurements indicate that retrocyclin-2 interacts with the SDS micelles, and such a membrane-like interaction may be an important feature in the mechanism of action of these antimicrobial peptides. Analytical ultracentrifugation and the NMR data indicated that retrocyclin-2 self-associates to form a trimer in a concentration-dependent manner. The ability to self-associate may contribute to the high-affinity binding of retrocyclins for glycoproteins by increasing the valency and enhancing the ability of retrocyclins to cross-link cell surface glycoproteins.
The intestinal guanylyl cyclase-C (GC-C) was originally identified as an Escherichia coli heat-stable enterotoxin (STa) receptor. STa stimulates GC-C to much higher activity than the endogenous ligands guanylin and uroguanylin, causing severe diarrhea. To investigate the interactions of the endogenous and bacterial ligands with GC-C, we designed and characterized a soluble and properly folded fragment of the extracellular ligand-binding domain of GC-C. The membrane-bound guanylyl cyclases exhibit a single transmembrane spanning helix and a globularly folded extracellular ligand-binding domain that comprises about 410 of 1050 residues. Based on the crystal structure of the dimerized-binding domain of the guanylyl cyclase-coupled atrial natriuretic peptide receptor and a secondary structure-guided sequence alignment, we generated a model of the extracellular domain of GC-C comprised of two subdomains. Mapping of mutational and cross-link data onto this structural model restricts the ligand-binding region to the membrane proximal subdomain. We thus designed miniGC-C, a 197 amino acid fragment that mimics the ligand-binding membrane proximal subdomain. Cloning, expression and spectroscopic studies reveal miniGC-C to be a soluble and properly folded protein with a distinct secondary and tertiary structure. MiniGC-C binds STa with nanomolar affinity.
A 16 y.o. fully ambulant boy born to consanguineous Indian parents, presented for assessment of a fragility femoral neck fracture sustained against a background of autism and moderately severe intellectual disability. He had a past history of infantile eczema, and epilepsy treated with anticonvulsants from 2 to 10 years of age, with no further seizures following cessation of anticonvulsants. He had a thin body habitus (see Table 1) with long fingers and a high arched palate. He had no speech and negligible social interaction, but physical examination was otherwise unremarkable. Positive investigations revealed an undetectable serum creatinine and a urinary metabolic screen which showed an elevated GUA:Phe of 160 (< 36) and a decreased creatinine of 0.3 mmol/l (1.2–29.5) consistent with the diagnosis of guanidinoacetate methyltransferase(GAMT) deficiency. He was commenced on oral creatine 5 g three times daily. Despite improvement in physical activity, height and bone density, there was no discernable improvement in his intellectual functioning. Proton and phosphorous brain and leg magnetic resonance spectroscopy(MRS) was performed at baseline and showed an increased inorganic phosphorus peak and decreased phosphocreatine synthesis in brain and decreased creatine concentration in muscle. Following creatine treatment total brain creatine(1H-MRS) and phosphocreatine/ATP ratio (31P-MRS) content increased to 30% and 60% of control values, respectively. Brain GUA returned to normal levels.
With SGF Profiling™ we introduce an NMR-based screening method for the quality control of fruit juices. This method has been developed in a joint effort by Bruker BioSpin GmbH and SGF International e.V. The system is fully automated with respect to sample transfer, measurement, data analysis and reporting and is set up on an Avance 400 MHz flow-injection NMR spectrometer. For each fruit juice a multitude of parameters related to quality and authenticity are evaluated simultaneously from a single data set acquired within a few minutes. This multimarker/multi-aspect NMR screening approach features low cost-per-sample and is highly competitive with conventional and targeted fruit juice quality control methods.
A select set of microalgae are reported to be able to catalyse photobiological H2 production from water. Based on the model organism Chlamydomonas reinhardtii, a method was developed for the screening of naturally occurring H2-producing microalgae. By purging algal cultures with N2 in the dark and subsequent illumination, it is possible to rapidly induce photobiological H2 evolution. Using NMR spectroscopy for metabolic profiling in C. reinhardtii, acetate, formate, and ethanol were found to be key compounds contributing to metabolic variance during the assay. This procedure can be used to test algal species existing as axenic or mixed cultures for their ability to produce H2. Using this system, five algal isolates capable of H2 production were identified in various aquatic systems. A phylogenetic tree was constructed using ribosomal sequence data of green unicellular algae to determine if there were taxonomic patterns of H2 production. H2-producing algal species were seen to be dispersed amongst most clades, indicating an H2-producing capacity preceded evolution of the phylum Chlorophyta.
The metabolome of the model species Chlamydomonas reinhardtii has been analyzed during 120 h of sulfur depletion to induce anaerobic hydrogen (H2) production, using NMR spectroscopy, gas chromatography coupled to mass spectrometry, and TLC. The results indicate that these unicellular green algae consume freshly supplied acetate in the medium to accumulate energy reserves during the first 24 h of sulfur depletion. In addition to the previously reported accumulation of starch, large amounts of triacylglycerides were deposited in the cells. During the early 24- to 72-h time period fermentative energy metabolism lowered the pH, H2 was produced, and amino acid levels generally increased. In the final phase from 72 to 120 h, metabolism slowed down leading to a stabilization of pH, even though some starch and most triacylglycerides remained. We conclude that H2 production does not slow down due to depletion of energy reserves but rather due to loss of essential functions resulting from sulfur depletion or due to a build-up of the toxic fermentative products formate and ethanol.
The use of fossil fuels is now widely accepted as unsustainable due to depleting resources and the accumulation of greenhouse gases in the environment that have already exceeded the “dangerously high” threshold of 450 ppm CO2-e. To achieve environmental and economic sustainability, fuel production processes are required that are not only renewable, but also capable of sequestering atmospheric CO2. Currently, nearly all renewable energy sources (e.g. hydroelectric, solar, wind, tidal, geothermal) target the electricity market, while fuels make up a much larger share of the global energy demand (∼66%). Biofuels are therefore rapidly being developed. Second generation microalgal systems have the advantage that they can produce a wide range of feedstocks for the production of biodiesel, bioethanol, biomethane and biohydrogen. Biodiesel is currently produced from oil synthesized by conventional fuel crops that harvest the sun’s energy and store it as chemical energy. This presents a route for renewable and carbon-neutral fuel production. However, current supplies from oil crops and animal fats account for only approximately 0.3% of the current demand for transport fuels. Increasing biofuel production on arable land could have severe consequences for global food supply. In contrast, producing biodiesel from algae is widely regarded as one of the most efficient ways of generating biofuels and also appears to represent the only current renewable source of oil that could meet the global demand for transport fuels. The main advantages of second generation microalgal systems are that they: (1) Have a higher photon conversion efficiency (as evidenced by increased biomass yields per hectare): (2) Can be harvested batch-wise nearly all-year-round, providing a reliable and continuous supply of oil: (3) Can utilize salt and waste water streams, thereby greatly reducing freshwater use: (4) Can couple CO2-neutral fuel production with CO2 sequestration: (5) Produce non-toxic and highly biodegradable biofuels. Current limitations exist mainly in the harvesting process and in the supply of CO2 for high efficiency production. This review provides a brief overview of second generation biodiesel production systems using microalgae.
The multidomain proteinase inhibitor LEKTI (lympho-epithelial Kazal-type related inhibitor) consists of 15 potential serine proteinase inhibitory domains. In various diseases such as the severe skin disorder Netherton syndrome as well as atopy, defects in the gene encoding LEKTI have been identified that generate premature termination codons of translation, suggesting a specific role of the COOH-terminal part of LEKTI in healthy individuals. We overexpressed and purified a sequence comprising the 15th domain of LEKTI for further characterisation. Here, we present a high yield expression system for recombinant production and efficient purification of LEKTI domain 15 as a highly soluble protein with a uniform disulfide pattern that is identical to that of other known Kazal-type inhibitors. Also, the expected P1P1′ site was confirmed. LEKTI domain 15 is a well-structured protein as verified by circular dichroism (CD) spectroscopy and a tight-binding and stable inhibitor of the serine proteinase trypsin. These findings confirm the designation of domain 15 as a proteinase inhibitor of the Kazal family.
Conotoxins are small conformationally constrained peptides found in the venom of marine snails of the genus Conus. They are usually cysteine rich and frequently contain a high degree of post-translational modifications such as C-terminal amidation, hydroxylation, carboxylation, bromination, epimerisation and glycosylation. Here we review the role of NMR in determining the three-dimensional structures of conotoxins and also provide a compilation and analysis of H-1 and C-13 chemical shifts of post-translationally modified amino acids and compare them with data from common amino acids. This analysis provides a reference source for chemical shifts of post-translationally modified amino acids. Copyright (C) 2006 John Wiley & Sons, Ltd.
In contrast to their prohormones the mature peptide hormones guanylin and uroguanylin are not able to fold to their native disulfide connectivities upon oxidative folding. Structural properties of both peptide hormones and their precursor proteins as well as the role of their prosequences in proper disulfide coupled folding are reviewed. In addition, the structural behavior of a proguanylin mutant that closely resembles prouroguanylin has been investigated to gain further insight into structural properties of this homologous precursor protein.