Low fermentable oligosaccharides, disaccharides,monosaccharides, and polyols diet in children

Irritable bowel syndrome (IBS) is a lifelong condition with a high prevalence among children and adults. As the diet is a frequent factor that triggers the symptoms, it has been assumed that by avoiding the consumption of fermentable oligosaccharides, disaccharides, monosaccharides and polyols (FODMAP), the symptoms might be improved. Therefore, in the past decade, low FODMAP diet has been intensively investigated in the management of IBS. The capacity of FODMAPs to trigger the symptoms in patients with IBS was related to the stimulation of mechanoreceptors in the small and large intestine. This stimulation appears as a response to a combination of increased luminal water (the osmotic effect) and the release of gases (carbon dioxide and hydrogen) due to the fermentation of oligosaccharides and malabsorption of fructose, lactose and polyols. Numerous studies have been published regarding the efficacy of a low FODMAP diet compared to a traditional diet in releasing the IBS symptoms in adults, but there are only a few studies in the juvenile population. The aim of this review is to analyze the current data on both low FODMAP diet in children with IBS and the effects on their nutritional status and physiological development, given the fact that it is a restrictive diet.

Self-assembly behavior of disaccharide-containing supra-amphiphiles

In this paper,supra-amphiphilic compounds containing disaccharides and azobenzene ends have been constructed via dynamic covalent bond.It was found that the slight structural difference of the disaccharides made significant difference in the self-assembled morphologies.Namely,three kinds of azodisaccharide supra-amphiphiles were found to assemble into different morphologies,with the only difference in chemical structure from the disaccharides.More importantly,the structural difference between the disaccharides,including lactoside,maltoside and cellobioside was trivial.Molecular simulation revealed the packing of molecules was due to the different contribution from hydrogen bonds.The above results clearly indicated the contribution of saccharide packing,especially the related hydrogen bonding,to the final morphology of the assembled structures.

Disaccharide phosphorylases: Structure, catalytic mechanisms and directed evolution

Disaccharide phosphorylases(DSPs)are carbohydrate-active enzymes with outstanding potential for the biocatalytic conversion of common table sugar into products with attractive properties.They are modular enzymes that form active homo-oligomers.From a mechanistic as well as a structural point of view,they are similar to glycoside hydrolases or glycosyltransferases.As the majority of DSPs show strict stereo-and regiospecificities,these enzymes were used to synthesize specific disaccharides.Currently,protein engineering of DSPs is pursued in different laboratories to broaden the donor and acceptor substrate specificities or improve the industrial particularity of naturally existing enzymes,to eventually generate a toolbox of new catalysts for glycoside synthesis.Herein we review the characteristics and classifications of reported DSPs and the glycoside products that they have been used to synthesize.

Diet and functional dyspepsia: Clinical correlates and therapeutic perspectives

Hypervigilance and symptoms anticipation,visceral hypersensitivity and gastroduodenal sensorimotor abnormalities account for the varied clinical presentation of functional dyspepsia(FD)patients.Many patients recognize meals as the main triggering factor;thus,dietary manipulations often represent the first-line management strategy in this cohort of patients.Nonetheless,scarce quality evidence has been produced regarding the relationship between specific foods and/or macronutrients and the onset of FD symptoms,resulting in nonstandardized nutritional approaches.Most dietary advises are indeed empirical and often lead to exclusion diets,reinforcing in patients the perception of“being intolerant”to food and self-perpetuating some of the very mechanisms underlying dyspepsia physiopathology(i.e.,hypervigilance and symptom anticipation).Clinicians are often uncertain regarding the contribution of specific foods to dyspepsia physiopathology and dedicated professionals(i.e.,dietitians)are only available in tertiary referral settings.This in turn,can result in nutritionally unbalanced diets and could even encourage restrictive eating behaviors in severe dyspepsia.In this review,we aim at evaluating the relationship between dietary habits,macronutrients and specific foods in determining FD symptoms.We will provide an overview of the evidence-based nutritional approach that should be pursued in these patients,providing clinicians with a valuable tool in standardizing nutritional advises and discouraging patients from engaging into indiscriminate food exclusions.

Current approach to treatment of minimal hepatic encephalopathy in patients with liver cirrhosis

Minimal hepatic encephalopathy(MHE)corresponds to the earliest stage of hepatic encephalopathy(HE).MHE does not present clinically detectable neurological-psychiatric abnormalities but is characterized by imperceptible neurocognitive alterations detected during routine clinical examination via neuropsychological or psychometrical tests.MHE may affect daily activities and reduce job performance and quality of life.MHE can increase the risk of accidents and may develop into overt encephalopathy,worsening the prognosis of patients with liver cirrhosis.Despite a lack of consensus on the therapeutic indication,interest in finding novel strategies for prevention or reversion has led to numerous clinical trials;their results are the main objective of this review.Many studies address the treatment of MHE,which is mainly based on the strategies and previous management of overt HE.Current alternatives for the management of MHE include measures to maintain nutritional status while avoiding sarcopenia,and manipulation of intestinal microbiota with non-absorbable disaccharides such as lactulose,antibiotics such as rifaximin,and administration of different probiotics.This review analyzes the results of clinical studies that evaluated the effects of different treatments for MHE.

Stereoselective Syntheses of Some β-D-1-Thioglycopyranosides and Bis(β-D-glycopyranosyl) Sulfides by Phase Transition Catalysis

The present paper covers the stereoselective syntheses of four 1 thiogalactopyranosides 1—4 and three thio disaccharides 5—7 through the PTC methods and their structures confirmed by means of elementary analysis, IR and NMR spectral data.

Nutritional Requirements for Mycelial Growth of <i>Ophiocordyceps sinensis</i>on Agar Media

Ophiocordyceps sinensis has been used as one of the most valuable traditional Chinese Medication. This fungus parasitizes larva of Hepialus armoricanus, and converts each larva into a sclerotium form, in which the fruit body grows. Due to the geographical limitation, where O. sinensis can only be found in Himalayas region, the natural resources are limited and very expensive. This research aims to compare the growth-rate of O. sinensis mycelia with different ingredients mix with agar media using one-factor-at-a-time method. This research demonstrated the mycelial growth-rate with different carbon sources, including monosaccharide (Fructose, Glucose), disaccharide (Maltose, Sucrose), and polysaccharide (Dextrin, Malt extract), complex organic nitrogen sources, including beef extract, yeast extract, whey protein, and soy protein, and eight different carbon to nitrogen ratios. The objective of this research is to find out the suitable carbon and organic complex nitrogen sources and ratio for the O. sinensis solid cultivation. As results, O. sinensis grew best with disaccharides comparing to the other types of carbon sources. Furthermore, O. sinensis preferred whey protein in contrast to other organic complex nitrogen sources. As for the carbon to nitrogen ratios, an optimal ratio of 18:1 was observed. Based on those experiments, carbon source shows a greater influence for the mycelial growth. Hence many different types of grains and cereals would be great candidates as the main ingredients for the O. sinensis solid cultivation.

Functional and structural characterization of Norovirus GII.6 in recognizing histo-blood group antigens

Noroviruses(NoVs)are the primary cause of acute gastroenteritis worldwide.Histo-blood group antigens(HBGAs)are receptors or attachment factors that affect the prevalence and host susceptibility of NoVs.GII.6 NoV is one of the predominant genotypes in humans,which recognizes the type ABO secretor of HBGAs.However,the structural basis of GII.6 NoV's interaction with HBGAs receptors remains elusive.In this study,we investigated the binding features of the GII.6 strain to HBGAs using saliva-and glycan-ELISA assays and characterized the molecular basis of the GII.6 virus that recognizes H disaccharide.We showed that the GII.6 P domain recognized some A and O secretor's saliva samples,most B secretor's saliva samples,and H disaccharide antigen,but did not bind non-secretors’saliva.Further,we determined the crystal structures of GII.6 and its complex with H disaccharides at 1.7Å,revealing that the P domain of GII.6 shares the conventional binding interface and mode of GII HBGAs.Single residue mutations at the GII.6-H binding sites could inhibit the binding of GII.6 to HBGAs,demonstrating that the interaction residues were crucial in maintaining NoV-glycan integrity.Finally,structural and sequence analyses showed that the major residues of the GII.6-H interaction were conserved among NoVs in the GII genogroup.Taken together,our study characterized the functional and structural features of GII.6 that allow it to interact with HBGAs,and shed light on NoV evolution,epidemiology,and anti-viral drug development.

A rapid method for extraction,purification and structure analysis of chondroitin sulfate from six marine tissues

This study was designed to establish a strategy for the extraction,purification,and structure analysis of chondroitin sulfate(cs)in milligram amounts.Crude acidic polysaccharides were extracted from six kinds of marine animals by enzymatic hydrolysis and hexadecylpyridinium chloride precipitation and purified by Q Sepharose Fast Flow strong anion exchange column.The purification of each crude polysaccharide was completed within 1 h.The structure of the polysaccharides,i.e.their chemical characterization,functional group,molecular weight and monosaccharide composition,were analyzed by colorimetry,nuclear magnetic resonace and high-performance liquid chromatogrpahy,respectively.All polysaccharides were identified as Cs.The oligosaccharide profile produced by enzyme hydrolysis of polysaccharides was determined by strong anion-exchange high-performance liquid chromatorgraphy.This method can be widely applied to the extraction and characterization of chondroitin sulfate from unknown raw materials,screening high-quality sources of functional polysaccharides,and laying a good foundation for thefollowing studyof the structure-function relationshipof polysaccharides.