Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 4.630
Filtrar
1.
Acta Crystallogr D Struct Biol ; 78(Pt 5): 613-622, 2022 May 01.
Artigo em Inglês | MEDLINE | ID: mdl-35503209

RESUMO

MalE is a maltose/maltodextrin-binding protein (MBP) that plays a critical role in most bacterial maltose/maltodextrin-transport systems. Previously reported wild-type MBPs are monomers comprising an N-terminal domain (NTD) and a C-terminal domain (CTD), and maltose-like molecules are recognized between the NTD and CTD and transported to the cell system. Because MBP does not undergo artificial dimerization, it is widely used as a tag for protein expression and purification. Here, the crystal structure of a domain-swapped dimeric MalE from Salmonella enterica (named SeMalE) in complex with maltopentaose is reported for the first time, and its structure is distinct from typical monomeric MalE family members. In the domain-swapped dimer, SeMalE comprises two subdomains: the NTD and CTD. The NTD and CTD of one molecule of SeMalE interact with the CTD and NTD of the partner molecule, respectively. The domain-swapped dimeric conformation was stabilized by interactions between the NTDs, CTDs and linkers from two SeMalE molecules. Additionally, a maltopentaose molecule was found to be located at the interface between the NTD and CTD of different SeMalE molecules. These results provide new insights that will improve the understanding of maltodextrin-binding MalE proteins.


Assuntos
Proteínas de Transporte , Salmonella enterica , Maltose , Proteínas Ligantes de Maltose , Polissacarídeos
2.
Anal Chim Acta ; 1206: 339770, 2022 May 08.
Artigo em Inglês | MEDLINE | ID: mdl-35473854

RESUMO

In this work, we report on the mercury thermometer-inspired test strip for potentiometric detection of salivary α-amylase (sAA). The test strip contains a reaction chamber and two split channels, which are connected by a curved hydrophobic channel. The detection of sAA is based on sequential two-step reactions with preloaded reagents on the test strip. In the first step, maltose is produced by catalyzing the hydrolysis of starch using sAA in the reaction chamber. In the second step, the test strip is shaken to introduce the reaction mixture to the split channels under the inertia force, similar to the operation of a mercury thermometer. In one split channel, maltose reduces [Fe(CN)6]3- to [Fe(CN)6]4- under the alkaline condition, while the reaction hardly occurs in the other split channel with the neutral condition. This leads to a difference in the ratio of [Fe(CN)6]3-/[Fe(CN)6]4- between the two channels and therefore a potential difference that can be measured and correlated to sAA concentration. Using this test strip, sAA in the human saliva sample was quantitatively analyzed within 2 min. The application of this technique in the psychological evaluation was also demonstrated.


Assuntos
Mercúrio , alfa-Amilases Salivares , Humanos , Maltose , Mercúrio/análise , Saliva/química , alfa-Amilases Salivares/análise , Termômetros
3.
Nanoscale ; 14(12): 4654-4670, 2022 Mar 24.
Artigo em Inglês | MEDLINE | ID: mdl-35262128

RESUMO

Anti-(ds)-DNA antibodies are the serological hallmark of Systemic Lupus Erythematosus (SLE). They assemble in the bloodstream with (ds)-DNA, forming immunocomplexes, which spread all over the body causing, among the other symptoms, lupic glomerulonephritis. Pathological manifestations of the disease may be reduced by destabilizing or inhibiting the formation of the immunocomplexes. In this respect, glycodendrimers showed peculiar interacting abilities towards this kind of biomolecule. Various generations of open-shell maltose-decorated poly(amidoamine) (PAMAM) and poly(propyleneimine) (PPI) dendrimers and two oligopeptides with different polyethylene glycol units were synthesized and characterized, and then tested for their anti-SLE activity. The activity of glycodendrimers and oligopeptides was evaluated in human plasma from patients with SLE, compared to healthy plasma, by means of an enzyme-linked immunosorbent assay (ELISA), and electron paramagnetic resonance (EPR) characterization using spin-label and spin-probe techniques. Different strategies for the immunocomplex formation were tested. The results show that both kinds of glycodendrimers and oligopeptides inhibited the formation of immunocomplexes. Also, a partial breakdown of preformed immunocomplexes was observed. Both ELISA and EPR analyses indicated a better activity of glycodendrimers compared to oligopeptides, the 3rd generation PPI dendrimer being the most promising against SLE. This study highlights the possibility to develop a new class of dendritic therapeutics for the treatment of Lupus in pre-clinical studies.


Assuntos
Dendrímeros , Lúpus Eritematoso Sistêmico , DNA , Dendrímeros/química , Dendrímeros/farmacologia , Ensaio de Imunoadsorção Enzimática , Humanos , Lúpus Eritematoso Sistêmico/tratamento farmacológico , Maltose/química , Maltose/farmacologia , Oligopeptídeos/farmacologia
4.
mSphere ; 7(2): e0003522, 2022 Apr 27.
Artigo em Inglês | MEDLINE | ID: mdl-35354279

RESUMO

Yeast species in the Wickerhamiella and Starmerella genera (W/S clade) thrive in the sugar-rich floral niche. We have previously shown that species belonging to this clade harbor an unparalleled number of genes of bacterial origin, among which is the SUC2 gene, encoding a sucrose-hydrolyzing enzyme. In this study, we used complementary in silico and experimental approaches to examine sucrose utilization in a broader cohort of species representing extant diversity in the W/S clade. Distinct strategies and modes of sucrose assimilation were unveiled, involving either extracellular sucrose hydrolysis through secreted bacterial Suc2 or intracellular assimilation using broad-substrate-range α-glucoside/H+ symporters and α-glucosidases. The intracellular pathway is encoded in two types of gene clusters reminiscent of the MAL clusters in Saccharomyces cerevisiae, where they are involved in maltose utilization. The genes composing each of the two types of MAL clusters found in the W/S clade have disparate evolutionary histories, suggesting that they formed de novo. Both transporters and glucosidases were shown to be functional and additionally involved in the metabolization of other disaccharides, such as maltose and melezitose. In one Wickerhamiella species lacking the α-glucoside transporter, maltose assimilation is accomplished extracellularly, an attribute which has been rarely observed in fungi. Sucrose assimilation in Wickerhamiella generally escaped both glucose repression and the need for an activator and is thus essentially constitutive, which is consistent with the abundance of both glucose and sucrose in the floral niche. The notable plasticity associated with disaccharide utilization in the W/S clade is discussed in the context of ecological implications and energy metabolism. IMPORTANCE Microbes usually have flexible metabolic capabilities and are able to use different compounds to meet their needs. The yeasts belonging to the Wickerhamiella and Starmerella genera (forming the so-called W/S clade) are usually found in flowers or insects that visit flowers and are known for having acquired many genes from bacteria by a process called horizontal gene transfer. One such gene, dubbed SUC2, is used to assimilate sucrose, which is one of the most abundant sugars in floral nectar. Here, we show that different lineages within the W/S clade used different solutions for sucrose utilization that dispensed SUC2 and differed in their energy requirements, in their capacity to scavenge small amounts of sucrose from the environment, and in the potential for sharing this resource with other microbial species. We posit that this plasticity is possibly dictated by adaptation to the specific requirements of each species.


Assuntos
Saccharomyces cerevisiae , Saccharomycetales , Glucose/metabolismo , Glucosídeos/metabolismo , Humanos , Maltose/metabolismo , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Saccharomycetales/genética , Sacarose/metabolismo
5.
Biosens Bioelectron ; 207: 114184, 2022 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-35339073

RESUMO

This study reports an economical and portable point-of-care (POC) monitoring device based on artificial multi-enzyme cascade systems for multiple detection purposes. The device was made up of a disposable three dimensional microfluidic paper-based analytical device (3D µPAD) with multiple detection zones and a smartphone readout. On-paper synthesis of a multifunctional mimetic composite, based on the CeO2 nanoparticles embedded in the amino-functionalized Fe metal-organic frameworks (CeO2@NH2-MIL-88B(Fe)), for cascade reactions was the main achievement of this work. The 3D µPAD was applied for simultaneous quantification of glucose, fructose, sucrose and maltose, and the detection process consisted of the enzymatic reaction of each sugar by anchored enzymes on the metal-organic frameworks (MOF) and successive oxidation of 3,3',5,5'-tetramethylbenzidine (TMB). Utilizing the new artificial mimicking system improved the color development uniformity and resulted in a reliable detection tool, with excellent detection limits in the range of 20-280 µM. It was directly applied to analyze the sugars levels of human total blood, urine, semen, honey and juice samples with the relative errors of less than 7.7% compared with the HPLC method. The cost-effective and easy-to-use µPAD has a great potential to be used in either medical diagnostics or the food industry. Also, it can be considered as a competitive POC method for patients in disadvantaged communities or emergencies.


Assuntos
Técnicas Biossensoriais , Estruturas Metalorgânicas , Nanopartículas , Técnicas Biossensoriais/métodos , Colorimetria , Frutose , Glucose , Humanos , Maltose , Papel , Sacarose
6.
PLoS One ; 17(3): e0264734, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35231077

RESUMO

The kinetics of growth and α-amylase production of a novel Candida wangnamkhiaoensis yeast strain were studied in single-stage steady-state continuous cultures. This was performed in a split-cylinder internal-loop airlift bioreactor, using a variety of carbon sources as fermentation substrates. Results showed that the steady-state yields of cell mass from carbohydrates were practically constant for the range of dilution rates assayed, equaling 0.535 ± 0.030, 0.456 ± 0.033, and 0.491 ± 0.035 g biomass/g carbohydrate, when glucose, maltose, and starch, respectively were used as carbon sources. No α-amylase activity was detected when glucose was used as the carbon source in the influent medium, indicating that α-amylase synthesis of C. wangnamkhiaoensis is catabolically repressed by glucose. Contrastingly, maltose and starch induce synthesis of α-amylase in C. wangnamkhiaoensis, with starch being the best α-amylase inducer. The highest α-amylase volumetric and specific activities (58400 ± 800 U/L and 16900 ± 200 U/g biomass, respectively), and productivities (14000 ± 200 U/L·h and 4050 ± 60 U/g biomass·h, respectively) were achieved at a dilution rate of 0.24 h-1 using starch as the carbon source. In conclusion, single-stage steady-state continuous culture in an airlift bioreactor represents a powerful tool, both for studying the regulatory mechanisms of α-amylase synthesis by C. wangnamkhiaoensis and for α-amylase production. Furthermore, results showed that C. wangnamkhiaoensis represents a potential yeast species for the biotechnological production of α-amylase, which can be used for the saccharification of starch. This offers an attractive renewable resource for the production of biofuels (particularly bioethanol), representing an alternative to fossil fuels with reduced cost of substrates.


Assuntos
Maltose , alfa-Amilases , Amilases , Reatores Biológicos , Carboidratos , Carbono , Glucose , Saccharomycetales , Amido
7.
Bioprocess Biosyst Eng ; 45(5): 969-979, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-35312865

RESUMO

Curdlan is an edible microbial polysaccharide and can be used in food, biomedical and biomaterial fields. To reduce the cost of curdlan production, this study investigated the suitability of cassava starch hydrolysates as carbon source for curdlan production. Cassava starch was hydrolyzed into maltose syrup using ß-amylase and pullulanase at various enzyme dosages, temperature, time and addition order of two enzymes. The maltose yield of 53.17% was achieved at starch loading 30% by simultaneous addition ß-amylase 210 U/g starch and pullulanase 3 U/g starch at 60 °C for 9 h. Cassava starch hydrolysates were used as carbon source for curdlan production by Agrobacterium sp. DH-2. The curdlan production reached 28.4 g/L with the yield of 0.79 g/g consumed sugar and molecular weight of 1.26 × 106 Da at 96 h with cassava starch hydrolysate at 90 g/L initial sugar concentration. Curdlan produced from cassava starch hydrolysates was characterized using FT-IR spectra and thermo gravimetric analysis. This work indicated that cassava starch was a potential renewable feedstock for curdlan production.


Assuntos
Manihot , beta-Amilase , Agrobacterium , Carbono , Maltose , Espectroscopia de Infravermelho com Transformada de Fourier , Amido , beta-Glucanas
8.
Proc Natl Acad Sci U S A ; 119(11): e2119980119, 2022 03 15.
Artigo em Inglês | MEDLINE | ID: mdl-35263224

RESUMO

SignificanceA gene regulatory system is an important tool for the engineering of biosynthetic pathways of organisms. Here, we report the development of an inducible-ON/OFF regulatory system using a malO operator as a key element. We identified and modulated sequence, position, numbers, and spacing distance of malO operators, generating a series of activating or repressive promoters with tunable strength. The stringency and robustness are both guaranteed in this system, a maximal induction factor of 790-fold was achieved, and nine proteins from different organisms were expressed with high yields. This system can be utilized as a gene switch, promoter enhancer, or metabolic valve in synthetic biology applications. This operator-based engineering strategy can be employed for developing similar regulatory systems in different microorganisms.


Assuntos
Bacillus subtilis , Vias Biossintéticas , Regulação Bacteriana da Expressão Gênica , Maltose , Engenharia Metabólica , Bacillus subtilis/efeitos dos fármacos , Bacillus subtilis/genética , Bacillus subtilis/metabolismo , Vias Biossintéticas/genética , Elementos Facilitadores Genéticos , Expressão Gênica , Regulação Bacteriana da Expressão Gênica/efeitos dos fármacos , Maltose/metabolismo , Maltose/farmacologia , Engenharia Metabólica/métodos , Regiões Operadoras Genéticas , Regiões Promotoras Genéticas/genética , Biologia Sintética
9.
Eur J Pharm Biopharm ; 174: 56-76, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-35337966

RESUMO

Intravenously administered iron-carbohydrate preparations are a structurally heterogenous class of nanomedicines. Iron biodistribution to target tissues is greatly affected by the physicochemical characteristics of these nanoparticles. Some regulatory agencies have recommended performing studies in animal models for biodistribution characterization and bioequivalence evaluation. In the present work, a systematic comparison of iron exposure, tissue biodistribution and pharmacodynamics of four intravenous iron-carbohydrates in anemic CD rats was conducted. A pilot study was performed to establish the anemic rat model, followed by a control study to evaluate the pharmacokinetics (serum iron, biodistribution) and pharmacodynamics (hematological parameters) in healthy and anemic controls and anemic rats receiving ferric carboxymaltose (FCM). The same parameters were then evaluated in a comparative study in anemic rats receiving FCM, iron sucrose (IS), iron isomaltoside 1000 (IIM), and iron dextran (ID). Despite similar serum iron profiles observed across the investigated nanomedicines, tissue iron biodistribution varied markedly between the individual intravenous iron-carbohydrate complexes. Tissue iron repletion differences were also confirmed by histopathology. These results suggest that employing serum iron profiles as a surrogate for tissue biodistribution may be erroneous. The variability observed in tissue biodistribution may indicate different pharmacodynamic profiles and warrants further study.


Assuntos
Ferro , Nanomedicina , Animais , Carboidratos , Compostos Férricos/química , Maltose , Projetos Piloto , Ratos , Distribuição Tecidual
10.
Anal Bioanal Chem ; 414(13): 3917-3925, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-35352163

RESUMO

In this study, carbonyldiimidazole was used to bond maltose-modified oligopeptides (Ala-Glu-Ala-Glu-Ala-Lys-Ala-Lys) to the surface of silica spheres for hydrophilic interaction liquid chromatography (HILIC). Attenuated total reflectance-Fourier transform infrared spectroscopy, elemental analysis, X-ray photoelectron spectroscopy, thermogravimetric analysis, BET technique, and water contact angle measurement results confirmed the successful immobilization of the obtained material. Compared with the conventional method for preparing carbohydrate stationary phases, this method involves simpler steps and less time-consuming processes. The experimental results proved that the retention mechanism of the maltose-based HILIC column matched the typical HILIC retention mechanism. The column showed high separation efficiency and stability toward the separation of polar compounds such as amino acids, bases, nucleosides, water-soluble vitamins, and salicylic acid and its analogs. The column achieved high selectivity toward oligosaccharide separation. In addition, this efficient analysis demonstrates the applicability of the as-prepared material in the field of food inspection.


Assuntos
Maltose , Nucleosídeos , Cromatografia Líquida/métodos , Interações Hidrofóbicas e Hidrofílicas , Oligopeptídeos , Sílica Gel , Dióxido de Silício/química , Água
11.
J Am Heart Assoc ; 11(7): e022214, 2022 Apr 05.
Artigo em Inglês | MEDLINE | ID: mdl-35301854

RESUMO

Background The mechanisms explaining the clinical benefits of ferric carboximaltose (FCM) in patients with heart failure, reduced or intermediate left ventricular ejection fraction, and iron deficiency remain not fully clarified. The Myocardial-IRON trial showed short-term cardiac magnetic resonance (CMR) changes suggesting myocardial iron repletion following administration of FCM but failed to find a significant increase in left ventricular ejection fraction in the whole sample. Conversely, the strain assessment could evaluate more specifically subtle changes in contractility. In this subanalysis, we aimed to evaluate the effect of FCM on the short-term left and right ventricular CMR feature tracking derived strain. Methods and Results This is a post hoc subanalysis of the double-blind, placebo-controlled, randomized clinical trial that enrolled 53 ambulatory patients with heart failure and left ventricular ejection fraction <50%, and iron deficiency [Myocardial-IRON trial (NCT03398681)]. Three-dimensional left and 2-dimensional right ventricular CMR tracking strain (longitudinal, circumferential, and radial) changes were evaluated before, 7 and 30 days after randomization using linear mixed-effect analysis. The median (interquartile range) age of the sample was 73 years (65-78), and 40 (75.5%) were men. At baseline, there were no significant differences in CMR feature tracking strain parameters across both treatment arms. At 7 days, the only global 3-dimensional left ventricular circumferential strain was significantly higher in the FCM treatment-arm (difference: -1.6%, P=0.001). At 30 days, and compared with placebo, global 3-dimensional left ventricular strain parameters significantly improved in those allocated to FCM treatment-arm [longitudinal (difference: -2.3%, P<0.001), circumferential (difference: -2.5%, P<0.001), and radial (difference: 4.2%, P=0.002)]. Likewise, significant improvements in global right ventricular strain parameters were found in the active arm at 30 days (longitudinal [difference: -3.3%, P=0.010], circumferential [difference: -4.5%, P<0.001], and radial [difference: 4.5%, P=0.027]). Conclusions In patients with stable heart failure, left ventricular ejection fraction <50%, and iron deficiency, treatment with FCM was associated with short-term improvements in left and right ventricular function assessed by CMR feature tracking derived strain parameters. Registration URL: https://www.clinicaltrials.gov; Unique identifier: NCT03398681.


Assuntos
Insuficiência Cardíaca , Função Ventricular Esquerda , Idoso , Compostos Férricos , Insuficiência Cardíaca/diagnóstico por imagem , Insuficiência Cardíaca/tratamento farmacológico , Humanos , Imagem Cinética por Ressonância Magnética/métodos , Espectroscopia de Ressonância Magnética , Masculino , Maltose/análogos & derivados , Volume Sistólico
12.
Bioprocess Biosyst Eng ; 45(5): 901-909, 2022 May.
Artigo em Inglês | MEDLINE | ID: mdl-35201399

RESUMO

Maltobionic acid (MBA) can be applied to various fields such as food, cosmetics, and pharmaceutical industries. In this study, whole-cell biocatalysis for MBA production was performed using recombinant Pseudomonas taetrolens homologously expressing quinoprotein glucose dehydrogenase (GDH). Various reaction parameters such as temperature, cell density, and cell harvest time, were optimized for improving MBA production. Under the optimized reaction conditions using pure maltose as a substrate, the MBA production titer, yield, and productivity of whole-cell biocatalyst (WCB) were 200 g/L, 95.6%, and 18.18 g/L/h, respectively, which were the highest compared to those reported previously. Productivity, a key factor for industrial MBA production, obtained from whole-cell biocatalysis in this study, was enhanced by approximately 1.9-fold compared to that obtained in our previous work (9.52 g/L/h) using the fermentation method. Additionally, the WCB could be reused up to six times without a significant reduction in MBA productivity, indicating that the WCB is very robust. Although MBA productivity (8.33 g/L/h) obtained from high-maltose corn syrup (HMCS) as a substrate was 45.8% of that using pure maltose, HMCS can be a better substrate for commercial MBA production because its price is only 1.1% of that of pure maltose. The results of this study using a WCB to convert maltose into MBA may support the development of a potential industrial process for more economically effective MBA production in the future.


Assuntos
Maltose , Zea mays , Biocatálise , Dissacarídeos , Pseudomonas
13.
Int J Food Microbiol ; 370: 109517, 2022 Jun 02.
Artigo em Inglês | MEDLINE | ID: mdl-35216827

RESUMO

Cronobacter is a common food-borne opportunistic pathogen, which is easily to form biofilm and difficult to remove. The regulation mechanism on the biofilm formation of Cronobacter has drawn more and more attention. In here, transcriptomic sequencing of free and biofilm states of Cronobacter was performed, and analyzed to identify the differential gene expression through Gene Ontology (GO) function, and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment. Based on sequencing analysis of the results, the malX gene encoding maltose transporter subunit IICB in the phosphotransferase system (PTS) might be involved in the formation of Cronobacter biofilm and thus selected for gene knockout. Hereafter, the changes in biofilm formation ability, extracellular polymer and biofilm-related gene expression of malX gene knockout strains were detected to explore the potential mechanism of malX gene on biofilm formation of Cronobacter. From the result, weaken biofilm formation ability of Cronobacter, decreased extracellular polysaccharide content and down-regulated expression of cellulose-related genes were obtained after knockout of malX gene, which verified our deduction. This study is the first to elucidates the regulation mechanism of the PTS on the biofilm formation of Cronobacter, which lays a foundation for the further prevention and control of food contamination caused by Cronobacter.


Assuntos
Cronobacter sakazakii , Cronobacter , Biofilmes , Cronobacter/genética , Cronobacter sakazakii/genética , Maltose/metabolismo , Fosfotransferases/metabolismo
14.
Eur J Gastroenterol Hepatol ; 34(6): 607-612, 2022 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-35102111

RESUMO

BACKGROUND: We evaluated an on-demand ferric carboxymaltose (FCM) infusion strategy in inflammatory bowel disease (IBD) patients with iron deficiency anemia (IDA). AIMS: The primary outcome was the response rate to single or multiple FCM infusions after 12 months. Secondary outcomes were the response rate to a single FCM infusion after 3 months and the FCM safety profile. METHODS: We retrospectively included 185 IBD patients who received at least one FCM infusion of 500 mg, between 2015 and 2018. FCM was administered to patients with Hb ≤10 g/dL and hypoferritinemia and repeated according to the physician's assessment. Complete response (CR) was defined as Hb ≥12 g/dL (≥13 g/dL for men) or Hb increase ≥2 g/dL. Partial response (PR) was defined as an Hb increase between 1 and 2 g/dL. A univariate analysis was performed at 3 and 12 months. RESULTS: After 12 months, the response rate was 75.1% (CR, 48.6%; PR, 26.4%; mean number of FCM infusions, 1.7 ± 1.1). In total 169/185 patients received a single FCM infusion during the first 3 months and 79.2% achieved response (CR, 56.8%; PR, 22.4%). At univariate analysis, no variable was associated with response. No adverse events were reported. CONCLUSIONS: An on-demand strategy was effective and well-tolerated in treating IDA in IBD patients.


Assuntos
Anemia Ferropriva , Doenças Inflamatórias Intestinais , Anemia Ferropriva/diagnóstico , Anemia Ferropriva/tratamento farmacológico , Anemia Ferropriva/etiologia , Doença Crônica , Compostos Férricos/efeitos adversos , Humanos , Doenças Inflamatórias Intestinais/tratamento farmacológico , Masculino , Maltose/efeitos adversos , Maltose/análogos & derivados , Estudos Retrospectivos , Resultado do Tratamento
15.
J Phys Chem A ; 126(9): 1486-1495, 2022 Mar 10.
Artigo em Inglês | MEDLINE | ID: mdl-35212541

RESUMO

Structure determination is a longstanding bottleneck of carbohydrate research. Tandem mass spectrometry (MS/MS) is one of the most widely used methods for carbohydrate structure determination. However, the effectiveness of MS/MS depends on how the precursor structures are derived from the observed fragments. Understanding the dissociation mechanisms is crucial for MS/MS-based structure determination. Herein, we investigate the collision-induced dissociation mechanism of ß-cellobiose and ß-maltose sodium adducts using quantum chemical calculations and experimental measurements. Four dissociation channels are studied. Dehydration mainly occurs through the transfer of an H atom to O1 of the sugar at the reducing end, followed by a C1-O1 bond cleavage; cross-ring dissociation starts with a ring-opening reaction, which occurs through the transfer of an H atom from O1 to O5 of the sugar at the reducing end. These two dissociation channels are analogous to that of glucose monosaccharide. The third channel, generation of B1 and Y1 ions, occurs through the transfer of an H atom from O3 (cellobiose) or O2 (maltose) to O1 of the sugar at the nonreducing end, followed by a glycosidic bond cleavage. The fourth channel, C1-Z1 fragmentation, has two mechanisms: (1) the transfer of an H atom from O3 or O2 to O4 of the sugar at the reducing end to generate C ions in the ring form and (2) the transfer of an H atom from O3 of the sugar at the reducing end to O5 of the sugar at the nonreducing end to produce C ions in the linear form. The results of calculations are supported by experimental collision-induced dissociation spectral measurements.


Assuntos
Maltose , Espectrometria de Massas em Tandem , Celobiose , Glucose , Íons/química , Espectrometria de Massas em Tandem/métodos
16.
BMC Pregnancy Childbirth ; 22(1): 157, 2022 Feb 25.
Artigo em Inglês | MEDLINE | ID: mdl-35216553

RESUMO

BACKGROUND: The objective of the FeminFER project was to assess the value of ferric carboxymaltose following a multicriteria decision analysis in obstetrics and gynaecology in Spain. METHODS: Ferric carboxymaltose (FCM) and ferrous sulphate were evaluated using the EVIDEM framework. Ten stakeholders participated to collect different perspectives. The framework was adapted considering evidence retrieved with a PICO-S search strategy and grey literature. Criteria/subcriteria were weighted by level of relevance and an evidence-based decision-making exercise was developed in each criterion; weights and scores were combined to obtain the value of intervention relative to each criterion/subcriterion, that were further combined into the Modulated Relative Benefit-Risk Balance (MRBRB). RESULTS: The most important criterion favouring FCM was Compared Efficacy/Effectiveness (0.183 ± 0.07), followed by Patient Preferences (0.059 ± 0.10). Only Direct medical costs criterion favoured FS (-0.003 ± 0.03). MRBRB favoured FCM; 0.45 ± 0.19; in a scale from -1 to + 1. CONCLUSIONS: In conclusion, considering the several criteria involved in the decision-making process, participants agreed with the use of FCM according to its MRBRB.


Assuntos
Anemia Ferropriva/tratamento farmacológico , Técnicas de Apoio para a Decisão , Compostos Férricos/uso terapêutico , Compostos Ferrosos/uso terapêutico , Maltose/análogos & derivados , Complicações Hematológicas na Gravidez/tratamento farmacológico , Feminino , Humanos , Maltose/uso terapêutico , Gravidez , Medição de Risco , Espanha/epidemiologia , Participação dos Interessados
18.
Biomolecules ; 12(2)2022 01 20.
Artigo em Inglês | MEDLINE | ID: mdl-35204667

RESUMO

This study aimed to synthesize maltitol using recombinant CGTase from Bacillus circulans A11 with ß-cyclodextrin (ß-CD) and sorbitol as a glucosyl donor and acceptor, respectively, and assess its antibacterial activity. Optimal conditions for producing the highest yield, 25.0% (w/w), were incubation of 1% (w/v) ß-CD and sorbitol with 400 U/mL of CGTase in 20 mM phosphate buffer at pH 6.0 and 50 °C for 72 h. Subsequently, maltitol underwent large-scale production and was purified by HPLC. By mass spectrometry, the molecular weight of the synthesized maltitol was 379.08 daltons, corresponding exactly to that of standard maltitol. The relative sweetness of synthesized and standard maltitol was ~90% of that of sucrose. Spot assay on the agar plate showed that maltitol inhibited the growth of Streptococcus mutans DMST 18777 cells. In addition, the MIC and MBC values of synthesized and standard maltitol against S. mutans were also determined as 20 and 40 mg/mL, respectively. These results show that the synthesized maltitol can be produced at high yields and has the potential to be used as an anticariogenic agent in products such as toothpaste.


Assuntos
Streptococcus mutans , Álcoois Açúcares , Maltose/análogos & derivados , Maltose/farmacologia , Sacarose/farmacologia , Álcoois Açúcares/farmacologia
19.
Carbohydr Polym ; 279: 118986, 2022 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-34980347

RESUMO

Isomaltodextrin (IMD) is a novel dietary fiber enzymatically produced by reconstructing the molecular chain structure of starch using glycosyltransferases. In this study, the specific prebiotic effects of α-1,6 linear and α-1,2 or α-1,3 branched IMDs with different molecular weights (Mw) on human intestinal bacteria were investigated by pure culture of single strains and mixed fermentation of human fecal microflora in vitro. The results showed that α-1,6 linear IMDs markedly promoted beneficial Bifidobacterium and Lactobacillus in both pure culture and mixed fermentation. α-1,3 branching exhibited similar selectivity with α-1,6 linkage but yielded more butyrate in pure cultures. In contrast, IMDs containing α-1,2 branches were utilized efficiently only during mixed fermentation, which was speculated to result from metabolic cross-feeding. Regarding Mw, IMDs with lower Mw showed better prebiotic effects in pure cultures but no differences in mixed culture. These findings provide a theoretical basis for their application as functional foods.


Assuntos
Dextrinas/farmacologia , Microbioma Gastrointestinal/efeitos dos fármacos , Glicosídeos/farmacologia , Maltose/análogos & derivados , Prebióticos , Acetatos/metabolismo , Bactérias/efeitos dos fármacos , Bactérias/genética , Bactérias/crescimento & desenvolvimento , Bactérias/metabolismo , Dextrinas/química , Fezes/microbiologia , Fermentação , Microbioma Gastrointestinal/genética , Glicosídeos/química , Humanos , Concentração de Íons de Hidrogênio , Ácido Láctico/metabolismo , Maltose/química , Maltose/farmacologia , Peso Molecular
20.
Paediatr Drugs ; 24(2): 137-146, 2022 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-35083718

RESUMO

BACKGROUND: Parenteral iron is generally considered safe in adults, and severe adverse events are extremely rare. Ferric carboxymaltose (FCM), a third-generation parenteral iron product, is not licensed for pediatric use. OBJECTIVE: The aim of this study was to present our data on the safety of FCM in children with iron deficiency (ID) and/or iron deficiency anemia (IDA) and to investigate through a systematic literature review articles reporting on the safety of FCM use in children with ID/IDA. PATIENTS AND METHODS: Safety data regarding children treated with FCM for ID/IDA from four pediatric departments in Greece over a 26-month period are presented. Additionally, a literature search was performed in PubMed, Scopus, and Google Scholar on December 4, 2021 for articles reporting on the use of FCM in children with ID/IDA. Review articles, guidelines, case reports/case series, and reports on the use of FCM for conditions other than ID/IDA were excluded. Identified articles were screened for all reported adverse events (AE) that were graded according to the Common Terminology Criteria for Adverse Events, version 5.0. RESULTS: In our cohort, 37 children with ID/IDA received 41 FCM infusions. All infusions were tolerated well. In addition, 11 articles reporting 1231 infusions of FCM in 866 children were identified in the literature. Among them, 52 (6%) children developed AE that were graded as mild or moderate (grades I-III). CONCLUSIONS: Our patient cohort and this literature review provide further evidence for the good safety profile of FCM in children, although well-designed prospective clinical trials with appropriate safety endpoints are still required.


Assuntos
Compostos Férricos , Maltose , Adulto , Criança , Compostos Férricos/efeitos adversos , Grécia , Humanos , Maltose/efeitos adversos , Maltose/análogos & derivados , Estudos Prospectivos
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...