Maltotriose

Screening of alpha-amylase/trypsin inhibitor activity in wheat, spelt and einkorn by high-performance thin-layer chromatography.[Pubmed:38687148]

Anal Methods. 2024 Apr 30.

alpha-Amylase/trypsin inhibitor proteins (ATI) are discussed as possible triggers for non-celiac gluten sensitivity. The potential of high-performance thin-layer chromatography (HPTLC) was studied for the first time to analyse the inhibitory properties of ATIs from flour of wheat, spelt, and einkorn. Inhibition by each flour of the digestive enzymes trypsin or alpha-amylase was determined by the reduction of released metabolisation products in comparison to non-digested flour, and positive (acarbose) and negative (water) controls. Firstly, amylolysis was carried out in miniaturized form on the HPTLC surface (HPTLC-nanoGIT) after in-vial pre-incubation of the amylase with the inhibitors from flour. alpha-Amylase inhibition was evident via the reduction of released saccharides, as analysed by normal phase HPTLC. A strong influence of the flour matrix on the assay results (individual saccharides) was evident, caused by an increased amylolysis of further polysaccharides present, making HPTLC analysis more reliable than currently used spectrophotometric sum value assays. The detection and visualization of such matrix influence helps to understand the problems associated with spectrophotometric assays. Only Maltotriose was identified as a reliable marker of the amylolysis. The highest alpha-amylase inhibition and thus the lowest saccharide response was detected for Maltotriose in refined spelt, whereas the lowest alpha-amylase inhibition and thus the highest saccharide response was detected for Maltotriose in refined wheat. A comparison of refined and whole grain flours showed no clear trend in the responses. Secondly, trypsin inhibition and proteolysis were performed in-vial, and any inhibition was evident via the reduction of released peptides, analysed by reversed-phase HPTLC. Based on the product pattern of the proteolysis, einkorn and whole wheat showed the highest trypsin inhibition, whereas refined wheat and refined spelt showed the lowest inhibition. Advantageously, HPTLC analysis provided important information on changes in individual saccharides or peptides, which was more reliable and sustainable than spectrophotometric in-vial assays (only sum value) or liquid column chromatography analysis (targeting only the ATI proteins).

Hepatic lipid accumulation is associated with multiple metabolic pathway alterations but not dyslipidemia and insulin resistance in central bearded dragons (Pogona vitticeps).[Pubmed:38593838]

Am J Vet Res. 2024 Apr 13:1-10.

OBJECTIVE: To investigate associations between hepatic fat accumulation, fibrosis, and plasma values of primary metabolites, biochemical measurands, insulin, and lipoproteins in bearded dragons. ANIMALS: 48 adult central bearded dragons (Pogona vitticeps). METHODS: Dragons were sedated with alfaxalone, and a blood sample was collected. Plasma was submitted for untargeted primary metabolomics using gas chromatography time-of-flight mass spectrometry, a biochemistry panel, and a lipoprotein panel determined by PAGE. Hepatic lipid content was quantified by liver attenuation measurements from CT images and digital image analysis of standardized histologic sections of the liver. Fibrosis was quantified by digital image analysis on Masson's trichrome-stained histologic sections. Severity was determined from pathologic review of liver sections according to a standardized grading system. Statistical associations were investigated using serial linear models adjusted for false discovery rate and multivariate statistics. RESULTS: Both hepatic fat and fibrosis had a significant effect on CT liver attenuation values. Several oligosaccharides (Maltotriose, maltose, ribose, trehalose) and alkaline phosphatase were significantly and linearly increased with hepatic lipid content (all q < .05). On partial least square-discriminant analysis, beta-hydroxybutyric acid was the most important discriminatory variable between fatty liver severity grades on histology. No significant associations were found with insulin, lipoproteins, and succinic acid. CLINICAL RELEVANCE: Bearded dragons with hepatic lipid accumulation experienced multiple metabolic pathway disruptions, some being compatible with mitochondrial dysfunction. No evidence of insulin resistance or dyslipidemia was found. Hepatic biopsy and histopathology remain recommended for reliably diagnosing and staging fatty liver disease in bearded dragons.

Nanochannel Stability of Chemically Converted Graphene Oxide Membranes.[Pubmed:38593376]

Small. 2024 Apr 9:e2311237.

Chemically converted graphene oxide laminate membranes, which exhibit stable interlayered nanochannels in aqueous environments, are receiving increasing attention owing to their potential for selective water and ion permeation. However, how the molecular properties of conversion agents influence the stabilization of nanochannels and how effectively nanochannels are stabilized have rarely been studied. In this study, mono-, di-, and tri-saccharide molecules of glucose (Glu), maltose (Glu2), and Maltotriose (Glu3) are utilized, respectively, to chemically modify graphene oxide (GO). The aim is to create nanochannels with different levels of stability and investigate how these functional conversion agents affect the separation performance. The effects of the property differences between different conversion agents on nanochannel stabilization are demonstrated. An agent with efficient chemical reduction of GO and limited intercalation in the resulting nanochannel ensures satisfactory nanochannel stability during desalination. The stabilized membrane nanochannel exhibits a permeance of 0.69 L m(-2) h(-1) bar(-1) and excellent Na(2)SO(4) rejection of 96.42%. Furthermore, this optimized membrane nanochannel demonstrates enhanced stability under varying external conditions compared to the original GO. This study provides useful information for the design of chemical conversion agents for GO nanochannel stabilization and the development of nanochannel membranes for precise separation.

Simultaneous improvement of thermostability and maltotriose-forming ability of a fungal alpha-amylase for bread making by directed evolution.[Pubmed:38431017]

Int J Biol Macromol. 2024 Apr;264(Pt 1):130481.

For applications in food industries, a fungal alpha-amylase from Malbranchea cinnamomea was engineered by directed evolution. Through two rounds of screening, a mutant alpha-amylase (mMcAmyA) was obtained with higher optimal temperature (70 degrees C, 5 degrees C increase) and better hydrolysis properties (18.6 % Maltotriose yield, 2.5-fold increase) compared to the wild-type alpha-amylase (McAmyA). Site-directed mutations revealed that Threonine (Thr) 226 Serine (Ser) substitution was the main reason for the property evolution of mMcAmyA. Through high cell density fermentation, the highest expression level of Thr226Ser was 3951 U/mL. Thr226Ser was further used for bread baking with a dosage of 1000 U/kg flour, resulting in a 17.8 % increase in specific volume and a 35.6 % decrease in hardness compared to the control. The results were a significant improvement on those of McAmyA. Moreover, the mutant showed better anti-staling properties compared to McAmyA, as indicated by the improved sensory evaluation after 4 days of storage at 4 and 25 degrees C. These findings provide insights into the structure-function relationship of fungal alpha-amylase and introduce a potential candidate for bread-making industry.

Metal-conjugated Maltotriose Chlorins as Novel Photosensitizers for Photodynamic Therapy.[Pubmed:38423643]

Anticancer Res. 2024 Mar;44(3):1011-1021.

BACKGROUND/AIM: Photodynamic therapy (PDT) is a relatively non-invasive anti-cancer therapy that employs a photosensitizer with a specific wavelength of light, causing a photochemical reaction that releases free radicals, thereby inducing tumor cell necrosis via oxidative stress. The oxygen molecule reaches the singlet excited state through efficient energy transfer from an excited triplet state of the photosensitizer. Heavy atoms are frequently introduced in photosensitizers for efficiently generating reactive oxygen species (ROS) in PDT, known as the heavy atom effect. However, metal-complexed photosensitizers often show low water-solubility. To overcome this limitation and produce ROS effectively, we focused on the better solubility of photosensitizers with heavy metals bound within the chlorin skeleton and conjugated with glucose in this study. MATERIALS AND METHODS: We established Maltotriose (Mal(3))-conjugation with heavy metallochlorins [M (Mal(3)-chlorin), M=Pt or Pd)] and evaluated its anti-tumor effect. RESULTS: M (Mal(3)-chlorin) showed effective ROS production and singlet oxygen induction. Consequently, these cytotoxic factors caused effective anti-tumor effects and induced morphological changes, followed by cell death in vitro. In a xenograft tumor mouse model, PDT with M (Mal(3)-chlorin) showed tumor growth suppression. CONCLUSION: M (Mal(3)-Chlorin) might be an excellent glucose-conjugated chlorin because of its strong anti-tumor PDT effect.

Leuconostoc mesenteroides and Liquorilactobacillus mali strains, isolated from Algerian food products, are producers of the postbiotic compounds dextran, oligosaccharides and mannitol.[Pubmed:38418710]

World J Microbiol Biotechnol. 2024 Feb 29;40(4):114.

Six lactic acid bacteria (LAB) isolated from Algerian sheep's milk, traditional butter, date palm sap and barley, which produce dextran, mannitol, oligosaccharides and vitamin B(2) have been characterized. They were identified as Leuconostoc mesenteroides (A4X, Z36P, B12 and O9) and Liquorilactobacillus mali (BR201 and FR123). Their exopolysaccharides synthesized from sucrose by dextransucrase (Dsr) were characterized as dextrans with (1,6)-D-glucopyranose units in the main backbone and branched at positions O-4, O-2 and/or O-3, with D-glucopyranose units in the side chain. A4X was the best dextran producer (4.5 g/L), while the other strains synthesized 2.1-2.7 g/L. Zymograms revealed that L. mali strains have a single Dsr with a molecular weight (Mw) of ~ 145 kDa, while the Lc. mesenteroides possess one or two enzymes with 170-211 kDa Mw. As far as we know, this is the first detection of L. mali Dsr. Analysis of metabolic fluxes from sucrose revealed that the six LAB produced mannitol (~ 12 g/L). The co-addition of maltose-sucrose resulted in the production of panose (up to 37.53 mM), an oligosaccharide known for its prebiotic effect. A4X, Z36P and B12 showed dextranase hydrolytic enzymatic activity and were able to produce another trisaccharide, Maltotriose, which is the first instance of a dextranase activity encoded by Lc. mesenteroides strains. Furthermore, B12 and O9 grew in the absence of riboflavin (vitamin B(2)) and synthesized this vitamin, in a defined medium at the level of ~ 220 mug/L. Therefore, these LAB, especially Lc. mesenteroides B12, are good candidates for the development of new fermented food biofortified with functional compounds.

Integration of non-targeted/targeted metabolomics and electronic sensor technology reveals the chemical and sensor variation in 12 representative yellow teas.[Pubmed:38268841]

Food Chem X. 2023 Dec 26;21:101093.

Yellow tea is a lightly fermented tea with unique sensory qualities and health benefits. However, chemical composition and sensory quality of yellow tea products have rarely been studied. 12 representative yellow teas, which were basically covered the main products of yellow tea, were chosen in this study. Combined analysis of non-targeted/targeted metabolomics and electronic sensor technologies (E-eye, E-nose, E-tongue) revealed the chemical and sensor variation. The results showed that yellow big tea differed greatly from yellow bud teas and yellow little teas, but yellow bud teas could not be effectively distinguished from yellow little teas based on chemical constituents and electronic sensory characteristics. Sensor variation of yellow teas might be attributed to some compounds related to bitterness and aftertaste-bitterness (4'-dehydroxylated gallocatechin-3-O-gallate, dehydrotheasinensin C, myricitin 3-O-galactoside, phloroglucinol), aftertaste-astringency (methyl gallate, 1,5-digalloylglucose, 2,6-digalloylglucose), and sweetness (Maltotriose). This study provided a comprehensive understanding of yellow tea on chemical composition and sensory quality.

alpha-L-Fucosidases from an Alpaca Faeces Metagenome: Characterisation of Hydrolytic and Transfucosylation Potential.[Pubmed:38255883]

Int J Mol Sci. 2024 Jan 9;25(2):809.

In various life forms, fucose-containing glycans play vital roles in immune recognition, developmental processes, plant immunity, and host-microbe interactions. Together with glucose, galactose, N-acetylglucosamine, and sialic acid, fucose is a significant component of human milk oligosaccharides (HMOs). Fucosylated HMOs benefit infants by acting as prebiotics, preventing pathogen attachment, and potentially protecting against infections, including HIV. Although the need for fucosylated derivatives is clear, their availability is limited. Therefore, synthesis methods for various fucosylated oligosaccharides are explored, employing enzymatic approaches and alpha-L-fucosidases. This work aimed to characterise alpha-L-fucosidases identified in an alpaca faeces metagenome. Based on bioinformatic analyses, they were confirmed as members of the GH29A subfamily. The recombinant alpha-L-fucosidases were expressed in Escherichia coli and showed hydrolytic activity towards p-nitrophenyl-alpha-L-fucopyranoside and 2'-fucosyllactose. Furthermore, the enzymes' biochemical properties and kinetic characteristics were also determined. All four alpha-L-fucosidases could catalyse transfucosylation using a broad diversity of fucosyl acceptor substrates, including lactose, Maltotriose, L-serine, and L-threonine. The results contribute insights into the potential use of alpha-L-fucosidases for synthesising fucosylated amino acids.

Raw starch degrading alkaline alpha-amylase from Geobacillus kaustophilus TSCCA02: Production, characterization, and its potential for application as a detergent additive.[Pubmed:38212247]

J Basic Microbiol. 2024 Apr;64(4):e2300653.

Geobacillus kaustophilus TSCCA02, a newly isolated strain from cassava (Manihot esculenta L.) rhizosphere soil in Thailand, showed maximum raw starch degrading enzyme (RSDE) activity at 252.3 +/- 9.32 U/mL with cassava starch and peptone at 5.0 and 3.0 g/L, respectively. 16 S ribosomal RNA (rRNA) sequencing and phylogenetic tree analyses indicated that the TSCCA02 strain was closely related to G. kaustophilus. The crude RSDE had optimal activity at 60 degrees C and pH 9.0. This enzyme degraded various kinds of starch including potato starch, cassava starch, rice flour, corn starch, glutinous rice flour, and wheat flour to produce sugar syrup at 60 degrees C, as confirmed by scanning electron microscopy (SEM), thin-layer chromatography (TLC), and Fourier-transform infrared spectroscopy (FTIR). The major end products of starch hydrolysis were maltose and Maltotriose with a small amount of glucose, confirming this enzyme as an alpha-amylase. The enzyme improved the washing efficiency of cotton fabric with commercial detergent. Results indicated the potential of alkaline alpha-amylase produced from a new isolate of G. kaustophilus TSCCA02 for application as a detergent additive on an industrial scale.

Isothermal titration calorimetry analysis of the binding between the maltodextrin binding protein malE of Staphylococcus aureus with maltodextrins of various lengths.[Pubmed:38211531]

Biochem Biophys Res Commun. 2024 Feb 5;695:149467.

Staphylococcus aureus (S. aureus), a Gram-positive bacterium, causes a wide range of infections, and diagnosis at an early stage is challenging. Targeting the maltodextrin transporter has emerged as a promising strategy for imaging bacteria and has been able to image a wide range of bacteria including S. aureus. However, little is known about the maltodextrin transporter in S. aureus, and this prevents new S. aureus specific ligands for the maltodextrin transporter from being developed. In Gram-positive bacteria, including S. aureus, the first step of maltodextrin transport is the binding of the maltodextrin-binding protein malE to maltodextrins. Thus, understanding the binding affinity and characteristics of malE from S. aureus is important to developing efficient maltodextrin-based imaging probes. We evaluated the affinity of malE of S. aureus to maltodextrins of various lengths. MalE of S. aureus (SAmalE) was expressed in E. coli BL21(DE3) and purified by Ni-NTA resin. The affinities of SAmalE to maltodextrins were evaluated with isothermal titration calorimetry. SAmalE has low affinity to maltose but binds to Maltotriose and longer maltodextrins up to maltoheptaose with affinities up to Ka = 9.02 +/- 0.49 x 10(5) M(-1). SAmalE binding to Maltotriose-maltoheptaose was exothermic and fit a single-binding site model. The van't Hoff enthalpy in the binding reaction of SAmalE with Maltotriose was 9.9 +/- 1.3 kcal/mol, and the highest affinity of SAmalE was observed with maltotetraose with Ka = 9.02 +/- 0.49 x 10(5) M(-1). In the plot of DeltaH-T*DeltaS, the of Enthalpy-Entropy Compensation effect was observed in binding reaction of SAmalE to maltodextrins. Acarbose and maltotetraiol bind with SAmalE indicating that SAmalE is tolerant of modifications on both the reducing and non-reducing ends of maltodextrins. Our results show that unlike ECmalE and similar to the maltodextrin binding protein of Streptococci, SAmalE primarily binds to maltodextrins via hydrogen bonds. This is distinct from the maltodextrin binding protein of Streptococci, SAmalE that binds to maltotetraiol with high affinity. Understanding the binding characteristics and tolerance to maltodextrins modifications by maltodextrin binding proteins will hopefully provide the basis for developing bacterial species-specific maltodextrin-based imaging probes.

Biodiversity and brewing attitude of non-Saccharomyces strains isolated from Uruguayan vineyards and other ecosystems.[Pubmed:38181520]

Int J Food Microbiol. 2024 Feb 16;412:110529.

In recent years, interest in non-Saccharomyces yeasts for the innovation and development of different and alternative beer styles has been increasing, especially for the microbrewing industry. This work studied the biodiversity of non-Saccharomyces yeasts based on isolates from grapes of different Uruguayan vineyards, craft breweries and raw materials, with the aim of selecting autochthonous non-Saccharomyces yeasts with a brewing attitude. Brewing tests were performed on synthetic wort developed for this purpose, and the evolution of alcoholic fermentation was monitored by measuring glucose, maltose, Maltotriose consumption, ethanol and glycerol production and final sensory analysis. A total of two hundred seventy-one yeast strains belonging to different genera were evaluated according to these parameters. After evaluating alcoholic fermentation performance, a native yeast strain belonging to the species Starmerella meliponinorum was selected due to its high Maltotriose consumption and glycerol production, making it a very promising brewing yeast, especially for production of low carbohydrate beers.

Retention behavior of carbohydrates on metal loaded chelating stationary phase under conditions of hydrophilic interaction liquid chromatography.[Pubmed:38065026]

J Chromatogr A. 2024 Jan 11;1714:464551.

The chromatographic retention of carbohydrates on chelating stationary phase loaded with different metal ions was studied under conditions of hydrophilic interaction chromatography (HILIC). The chelating stationary phases represented silica microparticles with immobilized 2-hydroxyethyliminodiacetic acid (HEIDA) groups in loose form and saturated with Ca(2+), Pb(2+), and La(3+)form. The role of loaded metal ion, the acetonitrile and methanol content in the mobile phase, buffer pH and column temperature on the retention of l-(+)-arabinose, d-(+)-maltose, l-(+)-rhamnose, d-(+)-lactose, d-(+)-xylose, glucose, fructose, sucrose, mannose, Maltotriose and d-(+) raffinose was studied. The investigation was mainly focused on possible contribution of the complexation in the stationary phase on retention of carbohydrates as well as on effect of the presence metal ion in HEIDA-silica on resulting HILIC behavior of. It is shown that adsorbents with immobilized metal complexes have a good potential for the separation of organic ligands under HILIC mode.

Selective utilization of gluco-oligosaccharides by lactobacilli: A mechanism study revealing the impact of glycosidic linkages and degree of polymerization on their utilization.[Pubmed:38010727]

J Food Sci. 2024 Jan;89(1):523-539.

Gluco-oligosaccharides (GlcOS) are potential prebiotics that positively modulate beneficial gut commensals like lactobacilli. For the rational design of GlcOS as prebiotics or combined with lactobacilli as synbiotics, it is important to establish the structure requirements of GlcOS and specificity toward lactobacilli. Herein, the utilization of 10 GlcOS with varied degrees of polymerization (DP) and glycosidic linkages by 7 lactobacilli strains (Levilactobacillus brevis ATCC 8287, Limosilactobacillus reuteri ATCC PTA 6475, Lacticaseibacillus rhamnosus ATCC 53103, Lentilactobacillus buchneri ATCC 4005, Limosilactobacillus fermentum FUA 3589, Lactiplantibacillus plantarum WCFS1, and Lactobacillus gasseri ATCC 33323) was studied. L. brevis ATCC 8287 was the only strain that grew on alpha/beta-(1-->4/6) linked disaccharides, whereas other strains showed diverse patterns, dependent on the availability of genes encoding sugar transporters and catabolic enzymes. The effect of DP on GlcOS utilization was strain dependent. beta-(1-->4) Linked cello-oligosaccharides (COS) supported the growth of L. brevis ATCC 8287 and L. plantarum WCFS1, and shorter COS (DP 2-3) were preferentially utilized over longer COS (DP 4-7) (consumption >/=90% vs. 40%-60%). alpha-(1-->4) Linked Maltotriose and maltodextrin (DP 2-11) were effectively utilized by L. brevis ATCC 8287, L. reuteri ATCC 6475, and L. plantarum WCFS1, but not L. fermentum FUA 3589. Growth of L. brevis ATCC 8287 on branched isomalto-oligosaccharides (DP 2-6) suggested preferential consumption of DP 2-3, but no preference between alpha-(1-->6) and alpha-(1-->4) linkages. The knowledge of the structure-specific GlcOS utilization by different lactobacilli from this study helps the structural rationale of GlcOS for prebiotic development.

Investigation of the allergenicity alterations of shrimp tropomyosin as glycated by glucose and maltotriose containing advanced glycation end products.[Pubmed:38009324]

Food Funct. 2023 Dec 11;14(24):10941-10954.

Tropomyosin (TM) is the major allergen in shrimp that is known to be the primary trigger for shrimp-induced food allergy. Our previous reports suggest that glycation could reduce the allergenicity of TM and the reduction of allergenicity is largely dependent on the sources of saccharides. This investigation aimed to investigate the glycation of TM by glucose and Maltotriose as well as the effects of glycation on the allergenicity of TM. Compared to TM, the IgG-binding capacity and IgE-binding capacity of tropomyosin glycated by glucose (TM-G) was greatly reduced with a longer glycation time, the release of allergic mediators from RBL-2H3 mast cells was reduced in a time-dependent manner, and weaker allergic reactions were induced in BALB/c mice. Conversely, tropomyosin glycated by Maltotriose (TM-MTS) exhibited a stronger allergenicity after 48 hours of glycation due to the generation of neoallergens that were derived from the advanced glycation end products (AGEs). In conclusion, glucose could be used to desensitize the shrimp TM-induced food allergy via glycation, which could significantly reduce the allergenicity and alleviate allergic symptoms. This work could provide a novel approach to reduce the allergenicity of shrimp tropomyosin and prevent the shrimp tropomyosin-induced food allergy.