Search results: Found 5

Listing 1 - 5 of 5
Sort by
Carbohydrates: The yet to be tasted sweet spot of immunity

Authors: ---
Book Series: Frontiers Research Topics ISSN: 16648714 ISBN: 9782889196258 Year: Pages: 93 DOI: 10.3389/978-2-88919-625-8 Language: English
Publisher: Frontiers Media SA
Subject: Medicine (General) --- Allergy and Immunology
Added to DOAB on : 2016-08-16 10:34:25
License:

Loading...
Export citation

Choose an application

Abstract

Carbohydrates are extremely abundant bio-molecules; they are on all mammalian cell surfaces as well as on bacterial cell surfaces. In mammals most secreted proteins are glycosylated, with the glycan component comprising a significant amount by mass of the glycoprotein. Although, many years ago carbohydrate-protein recognition events were demonstrated as involved in invertebrate self-non self recognition, the contribution of carbohydrate-protein binding events to the mechanisms of the mammalian immune response was not embraced with the same enthusiasm. Adaptive immunity and the contribution of antibodies, T cells and T-lymphocyte sub-sets and protein antigen presentation dominated immunological theory. Unlike protein structures, carbohydrate structures are not template driven yet the numerous enzymes involved in carbohydrate biosynthesis and modification are encoded by a major component of the genome, and the expression of these enzymes is tightly regulated. As a consequence carbohydrate structures are also regulated, with different structures appearing according to the stage of cell differentiation and according to the age or health of the individual. The advent of technologies that have allowed carbohydrate structures and carbohydrate-protein binding events to be more easily interrogated has resulted in these types of interactions taking their place in modern immunology. We now know that glycans and their ligands (or lectins) are involved in numerous immunological pathways of both the innate and adaptive systems. However, it is clear that our understanding is still in its infancy, as more and more examples where carbohydrate structures contribute to aspects of the immune response are being recognised. The goal of this research topic is to explore the variety of roles undertaken by glycans and lectins in all aspects of the immune response. The particular focus is how the interactions of glycans with their ligands contribute to the mechanism of immune responses.

Nutrition and the Function of the Central Nervous System

Author:
ISBN: 9783038970514 9783038970521 Year: Pages: X, 123 Language: english
Publisher: MDPI - Multidisciplinary Digital Publishing Institute
Subject: Nutrition and Food Sciences --- Biology
Added to DOAB on : 2018-08-09 17:50:23
License:

Loading...
Export citation

Choose an application

Abstract

Neuroscience, as a field, has only recently expanded to consider how the nervous system might be influenced by interaction with other bodily systems. The psychology curriculum never, for instance, included courses on nutrition. Although we learn about the body as if it is segregated into systems (cardiovascular, immune, digestive, etc.), these systems are not truly separate. If the aphorism, you are what you eat, is literally true: then you—your personality, thoughts, feelings, etc.—are, at least partly, a product of your diet. Such recognitions have spawned the new subdiscipline, nutritional neuroscience: the study of the role of diet on neurochemistry, neurobiology, cognition and behavior. This collection explores this exciting new area.

Asymmetric and Selective Biocatalysis

Authors: ---
ISBN: 9783038978466 9783038978473 Year: Pages: 154 DOI: 10.3390/books978-3-03897-847-3 Language: English
Publisher: MDPI - Multidisciplinary Digital Publishing Institute
Subject: Science (General) --- Chemistry (General)
Added to DOAB on : 2019-06-26 09:16:44
License:

Loading...
Export citation

Choose an application

Abstract

This Issue contains one communication, six articles, and two reviews. The communication from Paola Vitale et al. represents a work where whole cells were used as biocatalysts for the reduction of optically active chloroalkyl arylketones followed by a chemical cyclization to give the desired heterocycles. Among the various whole cells screened (baker’s yeast, Kluyveromyces marxianus CBS 6556, Saccharomyces cerevisiae CBS 7336, Lactobacillus reuteri DSM 20016), baker’s yeast provided the best yields and the highest enantiomeric ratios (95:5) in the bioreduction of the above ketones. In this respect, valuable chiral non-racemic functionalized oxygen-containing heterocycles (e.g., (S)-styrene oxide, (S)-2-phenyloxetane, (S)-2-phenyltetrahydrofuran), amenable to be further elaborated on, can be smoothly and successfully generated from their prochiral precursors. Studies about pure biocatalysts with mechanistical studies, application in different reactions, and new immobilization methods for improving their stability were reported in five different articles. The article by Su-Yan Wang et al. describes the cloning, expression, purification, and characterization of an N-acetylglucosamine 2-epimerase from Pedobacter heparinus (PhGn2E). For this, several N-acylated glucosamine derivatives were chemically synthesized and used to test the substrate specificity of the enzyme. The mechanism of the enzyme was studied by hydrogen/deuterium NMR. The study at the anomeric hydroxyl group and C-2 position of the substrate in the reaction mixture confirmed the epimerization reaction via ring-opening/enolate formation. Site-directed mutagenesis was also used to confirm the proposed mechanism of this interesting enzyme. The article by Forest H. Andrews et al. studies two enzymes, benzoylformate decarboxylase (BFDC) and pyruvate decarboxylase (PDC), which catalyze the non-oxidative decarboxylation of 2-keto acids with different specificity. BFDC from Pseudomonas putida exhibited very limited activity with pyruvate, whereas the PDCs from S. cerevisiae or from Zymomonas mobilis showed virtually no activity with benzoylformate (phenylglyoxylate). After studies using saturation mutagenesis, the BFDC T377L/A460Y variant was obtained, with 10,000-fold increase in pyruvate/benzoylformate. The change was attributed to an improvement in the Km value for pyruvate and a decrease in the kcat value for benzoylformate. The characterization of the new catalyst was performed, providing context for the observed changes in the specificity. The article by Xin Wang et al. compares two types of biocatalysts to produce D-lysine L-lysine in a cascade process catalyzed by two enzymes: racemase from microorganisms that racemize L-lysine to give D,L-lysine and decarboxylase that can be in cells, permeabilized cells, and the isolated enzyme. The comparison between the different forms demonstrated that the isolated enzyme showed the higher decarboxylase activity. Under optimal conditions, 750.7 mmol/L D-lysine was finally obtained from 1710 mmol/L L-lysine after 1 h of racemization reaction and 0.5 h of decarboxylation reaction. D-lysine yield could reach 48.8% with enantiomeric excess (ee) of 99%. In the article by Rivero and Palomo, lipase from Candida rugosa (CRL) was highly stabilized at alkaline pH in the presence of PEG, which permitted its immobilization for the first time by multipoint covalent attachment on different aldehyde-activated matrices. Different covalent immobilized preparation of the enzyme was successfully obtained. The thermal and solvent stability was highly increased by this treatment, and the novel catalysts showed high regioselectivity in the deprotection of per-O-acetylated nucleosides. The article by Robson Carlos Alnoch et al. describes the protocol and use of a new generation of tailor-made bifunctional supports activated with alkyl groups that allow the immobilization of proteins through the most hydrophobic region of the protein surface and aldehyde groups that allows the covalent immobilization of the previously adsorbed proteins. These supports were especially used in the case of lipase immobilization. The immobilization of a new metagenomic lipase (LipC12) yielded a biocatalyst 3.5-fold more active and 5000-fold more stable than the soluble enzyme. The PEGylated immobilized lipase showed high regioselectivity, producing high yields of the C-3 monodeacetylated product at pH 5.0 and 4 °C. Hybrid catalysts composed of an enzyme and metallic complex are also treated in this Special Issue. The article by Christian Herrero et al. describes the development of the Mn(TpCPP)-Xln10A artificial metalloenzyme, obtained by non-covalent insertion of Mn(III)-meso-tetrakis(p-carboxyphenyl)porphyrin [Mn(TpCPP), 1-Mn] into xylanase 10A from Streptomyces lividans (Xln10A). The complex was found able to catalyze the selective photo-induced oxidation of organic substrates in the presence of [RuII(bpy)3]2+ as a photosensitizer and [CoIII(NH3)5Cl]2+ as a sacrificial electron acceptor, using water as oxygen atom source. The two published reviews describe different subjects with interest in the fields of biocatalysis and mix metallic-biocatalysis, respectively. The review by Anika Scholtissek et al. describes the state-of-the-art regarding ene-reductases from the old yellow enzyme family (OYEs) to catalyze the asymmetric hydrogenation of activated alkenes to produce chiral products with industrial interest. The dependence of OYEs on pyridine nucleotide coenzyme can be avoided by using nicotinamide coenzyme mimetics. In the review, three main classes of OYEs are described and characterized. The review by Yajie Wang and Huimin Zhao highlights some of the recent examples in the past three years that combine transition metal catalysis with enzymatic catalysis. With recent advances in protein engineering, catalyst synthesis, artificial metalloenzymes, and supramolecular assembly, there is great potential to develop more sophisticated tandem chemoenzymatic processes for the synthesis of structurally complex chemicals. In conclusion, these nine publications give an overview of the possibilities of different catalysts, both traditional biocatalysts and hybrids with metals or organometallic complexes to be used in different processes—particularly in synthetic reactions—under very mild reaction conditions.

Nutrition During Pregnancy and Lactation: Implications for Maternal and Infant Health

Author:
ISBN: 9783039280544 9783039280551 Year: Pages: 238 DOI: 10.3390/books978-3-03928-055-1 Language: English
Publisher: MDPI - Multidisciplinary Digital Publishing Institute
Subject: Nutrition and Food Sciences --- Biology --- Science (General)
Added to DOAB on : 2020-01-30 16:39:46
License:

Loading...
Export citation

Choose an application

Abstract

Pregnancy is a viewed as a window to future health. With the birth of the developmental origins of human adult disease hypothesis, research and clinical practice has turned its attention to the influence of maternal factors such as health and lifestyle surrounding pregnancy as a means to understand and prevent the inter-generational inheritance of chronic disease susceptibility. Outcomes during pregnancy have long-lasting impacts on both women on children. Moreover, nutrition early in life can influence growth and the establishment of lifelong eating habits and behaviors. This Special Issue on “Nutrition during Pregnancy and Lactation: Implications for Maternal and Infant Health” is intended to highlight new epidemiological, mechanistic and interventional studies that investigate maternal nutrition around the pregnancy period on maternal and infant outcomes. Submissions may include original research, narrative reviews, and systematic reviews and meta-analyses.

Keywords

milk oligosaccharides --- infant formula --- 6?-sialyllactose --- cognitive development --- sialic acid --- maternal nutrition --- breast milk --- premature delivery --- milk composition --- nutritional intervention --- pregnant women --- overweight --- obesity --- total sugars --- energy --- vitamin B12 --- micronutrients --- pregnancy --- adolescents --- folate --- growth chart --- breastfeeding --- physiological body-weight loss --- thermal control --- basal maintenance expenditure --- maternal diet quality --- pregnancy --- lactation --- infancy --- growth --- body composition --- early programming --- hepatic lipogenesis --- insulin-resistant pregnancy --- metabolic flexibility --- non-alcoholic fatty liver disease --- slow digesting carbohydrates --- pregnancy --- gestational weight gain intervention --- eating behavior --- restraint --- disinhibition --- uncontrolled and emotional eating --- fetal growth --- overweight and obesity --- generalized linear models --- passive immunization --- antibodies --- lactation --- prematurity --- proteolysis --- breast milk --- full breastfeeding --- postpartum --- weight retention --- obesity --- prenatal intervention --- meal replacements --- randomized clinical trial --- lifestyle intervention --- obesity --- RDA --- micronutrients --- hippocampus --- DNA methylation --- DNA sequencing --- iron --- neurobiology --- transcriptome --- micronutrient deficiency --- neuroplasticity --- maternal obesity --- gestational weight gain --- immunological properties --- human milk --- nutrition --- health --- Pregnancy --- obesity --- diet quality --- Healthy Eating Index --- food cravings --- mindful eating --- education --- race --- food photography --- pregnancy --- energy expenditure --- energy intake --- physical activity --- metabolic rate --- fetal development

Lipopolysaccharides (LPSs)

Author:
ISBN: 9783039282562 9783039282579 Year: Pages: 390 DOI: 10.3390/books978-3-03928-257-9 Language: English
Publisher: MDPI - Multidisciplinary Digital Publishing Institute
Subject: Medicine (General) --- Allergy and Immunology
Added to DOAB on : 2020-04-07 23:07:08
License:

Loading...
Export citation

Choose an application

Abstract

The cytoplasm of Gram-negative bacteria is bound by three layers: an inner membrane, a layer of peptidoglycan, and an outer membrane. The outer membrane is an asymmetric lipidic bilayer, with phospholipids on its inner surface and lipopolysaccharides (LPSs) on the outside, with the latter being the major component of the outer leaflet and covering nearly three-quarters of the total outer cell surface. All LPSs possess the same general chemical architecture independently of bacterial activity (pathogenic, symbiotic, commensal), ecological niche (human, animal, soil, plant, water), or growth conditions. Endotoxins are large amphiphilic molecules consisting of a hydrophilic polysaccharide component and a covalently bound hydrophobic and highly conserved lipid component, termed lipid A (the endotoxin subunit). The polysaccharide component can be divided into two subdomains: the internal and conserved core region as well as the more external and highly variable O-specific chain, also referred to as the O-antigen due to its immunogenic properties. LPSs are endotoxins, one of the most potent class of activators of the mammalian immune system; they can be released from cell surfaces of bacteria during multiplication, lysis, and death. LPS can act through its biological center (lipid A component) on various cell types, of which macrophages and monocytes are the most important.

Keywords

aspirin --- hepcidin --- P65 (nuclear factor-?B) --- IL-6/JAK2/STAT3 pathway --- lipopolysaccharide (LPS) --- nitric oxide (NO) --- iron regulatory protein 1 (IRP1) --- Megalobrama amblycephala --- lipopolysaccharide induced TNF? factor --- lipopolysaccharide stimulation --- innate immune --- Aeromonas --- genomics --- inner core oligosaccharide --- outer core oligosaccharide --- lipopolysaccharide --- lipopolysaccharide --- Erwinia amylovora --- NMR --- ESI FT-ICR --- structural determination --- Bordetellae --- Bordetella holmesii --- endotoxin --- lipid A --- structure --- mass spectrometry --- genomic --- Edwardsiella tarda --- core oligosaccharide --- MALDI-TOF MS --- ESI MSn --- NMR --- genomic --- LPS tolerance --- hypothalamic inflammation --- insulin resistance --- pJNK --- fibroblast --- keratocyte --- cornea --- lipopolysaccharide --- bacteria --- chemokine --- adhesion molecule --- collagen --- tear fluid --- serum resistance --- complement --- Salmonella --- lipopolysaccharide --- sialic acid --- reptile-associated salmonellosis --- sepsis --- time response --- inflammation --- oxidative stress --- endotoxaemia --- mouse --- rat --- lipopolysaccharide --- double-stranded RNA --- epithelial cell --- dendritic cell --- allergic respiratory disorder --- hygiene hypothesis --- rhinovirus --- respiratory syncytial virus --- toll-like receptor --- LPS --- lipopolysaccharide --- heptosyltransferase --- protein dynamics --- glycosyltransferase --- GT-B --- inhibitor design --- lipopolysaccharide --- Coxiella burnetii --- Q fever --- phagosome --- virenose --- Plesiomonas shigelloides --- O-antigen --- lipopolysaccharide --- O-acetylation --- d-galactan I --- HR-MAS --- NMR spectroscopy --- endotoxin --- lipopolysaccharide --- Low Endotoxin Recovery --- phase transitions --- polysorbate --- LPS aggregates --- Small Angle X-ray Scattering --- MAT --- LAL and LER --- anti-conjugate serum --- core oligosaccharide --- lipopolysaccharide --- NMR spectroscopy --- ESI MS --- Proteus penneri

Listing 1 - 5 of 5
Sort by
Narrow your search