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1.
Food Microbiol ; 102: 103903, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-34809935

RESUMO

Two outbreaks of Shiga toxin-producing Escherichia coli O121:H19 associated with wheat flour, in the United States of America and Canada, involved strains with an unusual phenotype, delayed lactose utilization (DLU). These strains do not ferment lactose when initially cultured on MacConkey agar (MAC), but lactose fermentation occurs following subculture to a second plate of MAC. The prevalence of DLU was determined by examining the ß-galactosidase activity of 49 strains of E. coli O121, and of 37 other strains of E. coli. Twenty four of forty three O121:H19 and one O121:NM displayed DLU. Two strains (O121:NM and O145:H34) did not have detectable ß-galactosidase activity. ß-glucuronidase activity of O121 strains was also determined. All but six DLU strains had normal ß-glucuronidase activity. ß-glucuronidase activity was suppressed on MAC for 17 of 23 O121 non-DLU strains. Genomic analysis found that DLU strains possessed an insertion sequence, IS600 (1267 bp), between lacZ (ß-galactosidase) and lacY (ß-galactoside permease), that was not present in strains exhibiting normal lactose utilization. The insert might reduce the expression of ß-galactoside permease, delaying import of lactose, resulting in the DLU phenotype. The high probability of DLU should be considered when using lactose-containing media for the isolation of STEC O121.


Assuntos
Proteínas de Escherichia coli , Farinha/microbiologia , Lactose/metabolismo , Escherichia coli Shiga Toxigênica , Canadá , Proteínas de Escherichia coli/genética , Glucuronidase/genética , Proteínas de Membrana Transportadoras , Proteínas de Transporte de Monossacarídeos , Sorogrupo , Escherichia coli Shiga Toxigênica/genética , Escherichia coli Shiga Toxigênica/metabolismo , Simportadores , Triticum/microbiologia , Estados Unidos , beta-Galactosidase/genética
2.
J Sci Food Agric ; 102(1): 85-94, 2022 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-34031874

RESUMO

BACKGROUND: Epilactose, a potential prebiotics, was derived from lactose through enzymatic catalysis. However, production and purification of epilactose are currently difficult due to powerless enzymes and inefficient downstream processing steps. RESULTS: The encoding gene of cellobiose 2-epimerase (CE) from Caldicellulosiruptor sp. Rt8.B8 was cloned and expressed in Escherichia coli BL21(DE3). The enzyme was purified and it was suitable for industrial production of epilactose from lactose without by-products, because of high kcat (197.6 s-1 ) and preferable thermostability. The Rt8-CE gene was further expressed in the Bacillus subtilis strain. We successfully produced epilactose from 700 g L-1 lactose in 30.4% yield by using the recombinant Bacillus subtilis whole cells. By screening of a ß-galactosidase from Bacillus stearothermophilus (BsGal), a process for separating epilactose and lactose was established, which showed a purity of over 95% in a total yield of 69.2%. In addition, a mixed rare sugar syrup composed of epilactose and d-tagatose was successfully produced from lactose through the co-expression of l-arabinose isomerase and ß-galactosidase. CONCLUSION: Our study shed light on the efficient production of epilactose using a food-grade host expressing a novel CE enzyme. Moreover, an efficient and low-cost process was attempted to obtain high purity epilactose. In order to improve the utilization of raw materials, the production process of mixed syrup containing epilactose and d-tagatose with prebiotic properties produced from lactose was also established for the first time. © 2021 Society of Chemical Industry.


Assuntos
Bacillus subtilis/metabolismo , Proteínas de Bactérias/química , Caldicellulosiruptor/enzimologia , Celobiose/metabolismo , Dissacarídeos/biossíntese , Racemases e Epimerases/química , Bacillus subtilis/genética , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Caldicellulosiruptor/genética , Estabilidade Enzimática , Expressão Gênica , Temperatura Alta , Lactose/metabolismo , Racemases e Epimerases/genética , Racemases e Epimerases/metabolismo , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo
3.
Biochim Biophys Acta Gen Subj ; 1866(1): 130012, 2022 01.
Artigo em Inglês | MEDLINE | ID: mdl-34536507

RESUMO

BACKGROUND: The carbohydrate fraction of mammalian milk is constituted of lactose and oligosaccharides, most of which contain a lactose unit at their reducing ends. Although lactose is the predominant saccharide in the milk of most eutherians, oligosaccharides significantly predominate over lactose in the milk of monotremes and marsupials. SCOPE OF REVIEW: This review describes the most likely process by which lactose and milk oligosaccharides were acquired during the evolution of mammals and the mechanisms by which these saccharides are digested and absorbed by the suckling neonates. MAJOR CONCLUSIONS: During the evolution of mammals, c-type lysozyme evolved to α-lactalbumin. This permitted the biosynthesis of lactose by modulating the substrate specificity of ß4galactosyltransferase 1, thus enabling the concomitant biosynthesis of milk oligosaccharides through the activities of several glycosyltransferases using lactose as an acceptor. In most eutherian mammals the digestion of lactose to glucose and galactose is achieved through the action of intestinal lactase (ß-galactosidase), which is located within the small intestinal brush border. This enzyme, however, is absent in neonatal monotremes and macropod marsupials. It has therefore been proposed that in these species the absorption of milk oligosaccharides is achieved by pinocytosis or endocytosis, after which digestion occurs through the actions of several lysosomal acid glycosidases. This process would enable the milk oligosaccharides of monotremes and marsupials to be utilized as a significant energy source for the suckling neonates. GENERAL SIGNIFICANCE: The evolution and significance of milk oligosaccharides is discussed in relation to the evolution of mammals.


Assuntos
Lactose/metabolismo , Leite/metabolismo , Oligossacarídeos/metabolismo , Animais , Animais Lactentes/metabolismo , Evolução Biológica , Evolução Molecular , Galactose/metabolismo , Galactosiltransferases/metabolismo , Glucose/metabolismo , Lactalbumina/metabolismo , Lactose/genética , Mamíferos/metabolismo , Leite/química , Oligossacarídeos/genética
4.
Appl Environ Microbiol ; 87(20): e0105521, 2021 09 28.
Artigo em Inglês | MEDLINE | ID: mdl-34347516

RESUMO

Nutritional dependencies, especially those regarding nitrogen sources, govern numerous microbial positive interactions. As for lactic acid bacteria (LAB), responsible for the sanitary, organoleptic, and health properties of most fermented products, such positive interactions have previously been studied between yogurt bacteria. However, they have never been exploited to create artificial cocultures of LAB that would not necessarily coexist naturally, i.e., from different origins. The objective of this study was to promote LAB positive interactions, based on nitrogen dependencies in cocultures, and to investigate how these interactions affect some functional outputs, e.g., acidification rates, carbohydrate consumption, and volatile-compound production. The strategy was to exploit both proteolytic activities and amino acid auxotrophies of LAB. A chemically defined medium was thus developed to specifically allow the growth of six strains used, three proteolytic and three nonproteolytic. Each of the proteolytic strains, Enterococcus faecalis CIRM-BIA2412, Lactococcus lactis NCDO2125, and CIRM-BIA244, was cocultured with each one of the nonproteolytic LAB strains, L. lactis NCDO2111 and Lactiplantibacillus plantarum CIRM-BIA465 and CIRM-BIA1524. Bacterial growth was monitored using compartmented chambers to compare growth in mono- and cocultures. Acidification, carbohydrate consumption, and volatile-compound production were evaluated in direct cocultures. Each proteolytic strain induced different types of interactions: strongly positive interactions, weakly positive interactions, and no interactions were seen with E. faecalis CIRM-BIA2412, L. lactis NCDO2125, and L. lactis CIRM-BIA244, respectively. Strong interactions were associated with higher concentrations of tryptophan, valine, phenylalanine, leucine, isoleucine, and peptides. They led to higher acidification rates, lower pH, higher raffinose utilization, and higher concentrations of five volatile compounds. IMPORTANCE Interactions of lactic acid bacteria (LAB) are often studied in association with yeasts or propionibacteria in various fermented food products, and the mechanisms underlying their interactions are being quite well characterized. Concerning interactions between LAB, they have mainly been investigated to test antagonistic interactions. Understanding how they can positively interact could be useful in multiple food-related fields: production of fermented food products with enhanced functional properties or fermentation of new food matrices. This study investigated the exploitation of the proteolytic activity of LAB strains to promote positive interactions between proteolytic and nonproteolytic strains. The results suggest that proteolytic LAB do not equally stimulate nonproteolytic LAB and that the stronger the interactions between LAB are, the more functional outputs we can expect. Thus, this study gives insight into how to create new associations of LAB strains and to guarantee their positive interactions.


Assuntos
Lactobacillales/metabolismo , Interações Microbianas , Nitrogênio/metabolismo , Aminoácidos/metabolismo , Animais , Técnicas de Cocultura , Microbiologia de Alimentos , Lactobacillales/crescimento & desenvolvimento , Lactose/metabolismo , Lupinus , Leite , Peptídeos , Proteólise , Rafinose/metabolismo , Sacarose/metabolismo , Compostos Orgânicos Voláteis/metabolismo
5.
J Dairy Sci ; 104(10): 10566-10575, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34334201

RESUMO

Most ß-galactosidases reported are sensitive to the end product (galactose), making it the rate-limiting component for the efficient degradation of lactose through the enzymatic route. Therefore, there is ongoing interest in searching for galactose-tolerant ß-galactosidases. In the present study, the predicted galactose-binding residues of ß-galactosidase from Bacillus coagulans, which were determined by molecular docking, were selected for alanine substitution. The asparagine residue at position 148 (N148) is correlated with the reduction of galactose inhibition. Saturation mutations revealed that the N148C, N148D, N148S, and N148G mutants exhibited weaker galactose inhibition effects. The N148D mutant was used for lactose hydrolysis and exhibited a higher hydrolytic rate. Molecular dynamics revealed that the root mean square deviation and gyration radius of the N148D-galactose complex were higher than those of wild-type enzyme-galactose complex. In addition, the N148D mutant had a higher absolute binding free-energy value. All these factors may lead to a lower affinity between galactose and the mutant enzyme. The use of mutant enzyme may have potential value in lactose hydrolysis.


Assuntos
Bacillus coagulans , Lactose/metabolismo , beta-Galactosidase , Animais , Bacillus coagulans/enzimologia , Hidrólise , Simulação de Acoplamento Molecular , beta-Galactosidase/genética
6.
J Dairy Res ; 88(3): 357-365, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-34425920

RESUMO

The aim of this review was to present various topics related to lactose intolerance with special attention given to the role of fermented foods and probiotics in alleviating gastrointestinal symptoms. Lactose intolerance is a common digestive problem in which the human body is unable to digest lactose, known as milk sugar. Lactose intolerance can either be hereditary or a consequence of intestinal diseases. Recent work has demonstrated that fermented dairy products and probiotics can modify the metabolic activities of colonic microbiota and may alleviate the symptoms of lactose intolerance. We suggest that, lactose free dairy products could be recommended as alternatives for the alleviation of lactose intolerance and for the promotion of human health and wellness.


Assuntos
Intolerância à Lactose/terapia , Probióticos , Animais , Colo/microbiologia , Laticínios/análise , Microbioma Gastrointestinal/fisiologia , Humanos , Lactase/deficiência , Lactase/metabolismo , Lactose/análise , Lactose/metabolismo , Probióticos/uso terapêutico
7.
J Dairy Sci ; 104(10): 10744-10752, 2021 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-34218911

RESUMO

In our previous studies, we revealed the effect of lactose inclusion in calf starters on the growth performance and gut development of calves. We conducted the present study as a follow-up study to identify the shift in rumen microbiota and its relation to rumen fermentation when calves are fed a lactose-containing starter. Thirty Holstein bull calves were divided into 2 calf starter treatment groups: texturized calf starter (i.e., control; n = 15) or calf starter in which starch was replaced with lactose at 10% (i.e., LAC10; n = 15) on a dry matter basis. All calves were fed their respective treatment calf starter ad libitum from d 7, and kleingrass hay from d 35. Rumen digesta were collected on d 80 (i.e., 3 wk after weaning) and used to analyze rumen microbiota and fermentation products. There was no apparent effect of lactose feeding on the α-diversity and overall composition of rumen microbiota. Amplicon sequencing and real-time PCR quantification of the 16S rRNA gene confirmed that the abundance of butyrate-producing bacteria (i.e., Butyrivibrio group and Megasphaera elsdenii) did not differ between the control and LAC10 groups. Conversely, the relative abundance of Mitsuokella spp., which produce lactate, succinate, and acetate, was significantly higher in the rumen of calves that were fed lactose, whereas the lactate concentration did not differ between the control and LAC10 groups. These findings suggest that the lactate production can be elevated by an increase of Mitsuokella spp. and then converted into butyrate, not propionate, since the proportion of propionate was lower in lactose-fed calves. In addition, we observed a higher abundance of Coriobacteriaceae and Pseudoramibacter-Eubacterium in the LAC10 group. Both these bacterial taxa include acetate-producing bacteria, and a positive correlation between the acetate-to-propionate ratio and the abundance of Pseudoramibacter-Eubacterium was observed. Therefore, the higher abundance of Coriobacteriaceae, Mitsuokella spp., and Pseudoramibacter-Eubacterium in the rumen of lactose-fed calves partially explains the increase in the proportion of rumen acetate that was observed in our previous study.


Assuntos
Microbiota , Rúmen , Ração Animal/análise , Animais , Peso Corporal , Bovinos , Dieta/veterinária , Fermentação , Seguimentos , Lactose/metabolismo , Masculino , RNA Ribossômico 16S/genética , RNA Ribossômico 16S/metabolismo , Rúmen/metabolismo , Desmame
8.
Molecules ; 26(12)2021 Jun 16.
Artigo em Inglês | MEDLINE | ID: mdl-34208735

RESUMO

Saccharides are the most common carbon source for Streptococcus thermophilus, which is a widely used bacterium in the production of fermented dairy products. The performance of the strain is influenced by the consumption of different saccharides during fermentation. Therefore, a precise measurement of the concentrations of saccharides in the fermentation media is essential. An 18-min long method with limits of quantitation in the range of 0.159-0.704 mg/L and with 13C labelled internal standards employing hydrophilic interaction chromatography coupled to mass spectrometric detection-(HILIC-LC-MS) allowed for simultaneous quantification of five saccharides: fructose, glucose, galactose, sucrose, and lactose in the fermentation samples. The method included a four-step sample preparation protocol, which could be easily applied to high-throughput analysis. The developed method was validated and applied to the fermentation samples produced by Streptococcus thermophilus.


Assuntos
Cromatografia Líquida/métodos , Fermentação/fisiologia , Espectrometria de Massas em Tandem/métodos , Dissacarídeos/química , Dissacarídeos/metabolismo , Frutose/metabolismo , Galactose/metabolismo , Glucose/metabolismo , Lactose/metabolismo , Monossacarídeos/química , Monossacarídeos/metabolismo , Streptococcus thermophilus/metabolismo , Sacarose/metabolismo
9.
Food Chem ; 362: 130195, 2021 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-34082294

RESUMO

The aim of this study was to optimize and compare the production of galactooligosaccharides (GOSs) by free and cotton cloth-immobilized Aspergillus oryzae ß-galactosidase, and perform economical evaluation of production of GOSs (100%) between them. Using the response surface method, the optimal reaction time (3.9 h), initial lactose concentration (57.13%), and enzyme to lactose ratio (44.81 U/g) were obtained for the free enzyme, which provided a GOSs yield of 32.62%. For the immobilized enzyme, the optimal yield of GOSs (32.48%) was obtained under reaction time (3.09 h), initial lactose concentration (52.74%), and temperature (50.0 ℃). And it showed desirable reusability during five successive enzymatic reactions. The recovery rate of GOSs (100%) is 65% using silica gel filtration chromatography. The economical evaluation showed almost no difference in the manufacturing cost for the GOSs (100%) between these two systems, and that the recovery rate had a great impact on the cost.


Assuntos
Aspergillus oryzae/enzimologia , Enzimas Imobilizadas/química , Oligossacarídeos/biossíntese , beta-Galactosidase/química , Cromatografia em Gel , Custos e Análise de Custo , Enzimas Imobilizadas/metabolismo , Lactose/química , Lactose/metabolismo , Oligossacarídeos/química , Oligossacarídeos/economia , Oligossacarídeos/isolamento & purificação , Sílica Gel , Espectroscopia de Infravermelho com Transformada de Fourier , Temperatura , beta-Galactosidase/metabolismo
10.
Food Chem ; 361: 130136, 2021 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-34051599

RESUMO

Alterations in surface chemical composition relating to rehydration properties of spray-dried camel milk powders during accelerated storage (11-33% RH, 37 °C) over 18 weeks were investigated. The results showed that the surface of the fresh spray-dried camel milk powder (t = 0) was dominated by lipids (78%), followed by proteins (16%) and lactose (6%). During storage, the surface protein and lactose content decreased while the surface lipid content increased, resulting in an increase in surface hydrophobicity and slight agglomeration of the powder, especially for powder kept at 33% RH. Although fresh camel milk powder had very poor wettability, it displayed very high dispersibility and solubility (99%). During storage, dispersibility and solubility declined with increasing storage time and increasing RH levels, which correlated with an increase in surface lipid content. However, at the end of the storage period, camel milk powder still retained very high solubility (>93%).


Assuntos
Camelus , Leite/química , Animais , Interações Hidrofóbicas e Hidrofílicas , Lactose/química , Lactose/metabolismo , Pós/química , Solubilidade , Propriedades de Superfície , Molhabilidade
11.
Food Chem ; 359: 129890, 2021 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-33934029

RESUMO

A new support for the immobilization of ß-d-galactosidase from Kluyveromyces lactis was developed, consisting of mesoporous silica/titania with a chitosan coating. This support presents a high available surface area and adequate pore size for optimizing the immobilization efficiency of the enzyme and, furthermore, maintaining its activity. The obtained supported biocatalyst was applied in enzyme hydrolytic activity tests with o-NPG, showing high activity 1223 Ug-1, excellent efficiency (74%), and activity recovery (54%). Tests of lactose hydrolysis in a continuous flow reactor showed that during 14 days operation, the biocatalyst maintained full enzymatic activity. In a batch system, after 15 cycles, it retained approximately 90% of its initial catalytic activity and attained full conversion of the lactose 100% (±12%). Additionally, with the use of the mesoporous silica/titania support, the biocatalyst presented no deformation and fragmentation, in both systems, demonstrating high operational stability and appropriate properties for applications in food manufacturing.


Assuntos
Quitosana , Enzimas Imobilizadas/metabolismo , Kluyveromyces/enzimologia , Dióxido de Silício , Titânio , beta-Galactosidase/metabolismo , Proteínas de Bactérias/metabolismo , Estabilidade Enzimática , Hidrólise , Lactose/metabolismo
12.
Nutrients ; 13(5)2021 Apr 29.
Artigo em Inglês | MEDLINE | ID: mdl-33946892

RESUMO

Recent discoveries in the "omics" field and the growing focus on preventive health have opened new avenues for personalized nutrition (PN), which is becoming an important theme in the strategic plans of organizations that are active in healthcare, food, and nutrition research. PN holds great potential for individual health optimization, disease management, public health interventions, and product innovation. However, there are still multiple challenges to overcome before PN can be truly embraced by the public and healthcare stakeholders. The diagnosis and management of lactose intolerance (LI), a common condition with a strong inter-individual component, is explored as an interesting example for the potential role of these technologies and the challenges of PN. From the development of genetic and metabolomic LI diagnostic tests that can be carried out in the home, to advances in the understanding of LI pathology and individualized treatment optimization, PN in LI care has shown substantial progress. However, there are still many research gaps to address, including the understanding of epigenetic regulation of lactase expression and how lactose is metabolized by the gut microbiota, in order to achieve better LI detection and effective therapeutic interventions to reverse the potential health consequences of LI.


Assuntos
Intolerância à Lactose/dietoterapia , Ciências da Nutrição , Medicina de Precisão , Epigênese Genética , Humanos , Lactase/genética , Lactase/metabolismo , Lactose/metabolismo , Intolerância à Lactose/fisiopatologia
13.
Sci Rep ; 11(1): 10224, 2021 05 13.
Artigo em Inglês | MEDLINE | ID: mdl-33986316

RESUMO

Human milk (HM) composition is known to be highly variable, both between individuals and across the duration of lactation. It is less clear, however, to what extent fat, lactose and protein concentrations in HM change daily over shorter time periods in mature HM, and no studies have evaluated this to date. The aim of this study was to systematically assess and compare HM macronutrient concentrations in samples collected at different times of day, from left and right breasts and daily across a 3-week period in the same woman. Fifteen lactating women (1.6-4.9 months postpartum) collected daily pre-feed HM samples from both breasts each morning for 21 consecutive days and completed intensive sampling once a week (morning, afternoon and evening samples) during this period. Concentrations of fat, protein and lactose in HM did not differ according to time of day, day of week or breast used for collection. The results of this study suggest that pre-feed samples collected at any point across a 3-week period and from either the left or right breast provide comparable measures of fat, protein and lactose concentrations in mature HM, in pragmatic studies where women are collecting their own HM samples.Clinical trial registration: Australian New Zealand Clinical Trials Registry (ACTRN12619000606189).


Assuntos
Leite Humano/química , Leite Humano/metabolismo , Nutrientes/análise , Adulto , Austrália , Aleitamento Materno/métodos , Feminino , Humanos , Lactação/fisiologia , Lactose/metabolismo , Proteínas do Leite/metabolismo , Fatores de Tempo
14.
Int J Food Microbiol ; 349: 109230, 2021 Jul 02.
Artigo em Inglês | MEDLINE | ID: mdl-34023621

RESUMO

A mechanistic, spatio-temporal model to predict early stage semi-solid food ripening, exemplary for semi-solid casein matrices, was created using software based on the finite element method (FEM). The model was refined and validated by experimental data obtained during 8 wk of ripening of a casein matrix that was inoculated by one single central injection of starter culture. The resulting spatio-temporal distributions of lactococci strains, lactose, lactic acid/lactate and pH allowed us to optimize a number of parameters of the predictive model. Using the optimized model, the agreement between simulation and experiment was found to be satisfactory, with the pH matching best. The predictive model unveiled that effective diffusion of substrate and metabolites were crucial for an eventual homogeneous distribution of the measured substances. Hence, while using the optimized parameters from the single injection model, an injection technology for starter culture to inoculate and ferment casein matrices homogeneously was developed by means of solving another optimization problem with respect to injection positions. The casein matrix inoculated by the proposed injection pattern (21 injections, distance = 19 mm) showed sufficient homogeneity (bacterial activity and pH distribution) after the early stages of ripening, demonstrating the potential of application of the injection technology for fermentation of casein-based foods e.g. cheese.


Assuntos
Caseínas/análise , Manipulação de Alimentos/métodos , Modelos Teóricos , Caseínas/metabolismo , Queijo/análise , Queijo/microbiologia , Fermentação , Microbiologia de Alimentos , Concentração de Íons de Hidrogênio , Ácido Láctico/metabolismo , Lactococcus/metabolismo , Lactose/metabolismo
15.
Int J Mol Sci ; 22(7)2021 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-33808202

RESUMO

Active transport of sugars into bacteria occurs through symporters driven by ion gradients. LacY is the most well-studied proton sugar symporter, whereas vSGLT is the most characterized sodium sugar symporter. These are members of the major facilitator (MFS) and the amino acid-Polyamine organocation (APS) transporter superfamilies. While there is no structural homology between these transporters, they operate by a similar mechanism. They are nano-machines driven by their respective ion electrochemical potential gradients across the membrane. LacY has 12 transmembrane helices (TMs) organized in two 6-TM bundles, each containing two 3-helix TM repeats. vSGLT has a core structure of 10 TM helices organized in two inverted repeats (TM 1-5 and TM 6-10). In each case, a single sugar is bound in a central cavity and sugar selectivity is determined by hydrogen- and hydrophobic- bonding with side chains in the binding site. In vSGLT, the sodium-binding site is formed through coordination with carbonyl- and hydroxyl-oxygens from neighboring side chains, whereas in LacY the proton (H3O+) site is thought to be a single glutamate residue (Glu325). The remaining challenge for both transporters is to determine how ion electrochemical potential gradients drive uphill sugar transport.


Assuntos
Proteínas de Membrana Transportadoras/química , Proteínas de Membrana Transportadoras/metabolismo , Proteínas de Transporte de Sódio-Glucose/química , Proteínas de Transporte de Sódio-Glucose/metabolismo , Sítios de Ligação , Transporte Biológico Ativo , Proteínas de Escherichia coli/química , Proteínas de Escherichia coli/metabolismo , Glucose/metabolismo , Lactose/metabolismo , Modelos Moleculares , Proteínas de Transporte de Monossacarídeos/química , Proteínas de Transporte de Monossacarídeos/metabolismo , Conformação Proteica , Açúcares/metabolismo , Simportadores/química , Simportadores/metabolismo
16.
Nutr Res ; 89: 23-34, 2021 05.
Artigo em Inglês | MEDLINE | ID: mdl-33887513

RESUMO

Lactose intolerance has a high prevalence worldwide, ranging between 57% and 65%. It is caused by a reduction or loss of the activity of the intestinal enzyme lactase-phlorizin hydrolase, responsible for the digestion of lactose. This alteration determines an increased osmotic load in the small intestine and the fermentation of lactose by the bacterial flora, which leads to a high production of short-chain fatty acids and gas. This is followed by the onset of abdominal pain, diarrhea, and flatulence. In addition to these problems, it was found that subjects with lactose intolerance have an increased risk of developing various extra-intestinal diseases, including cancers. The diagnosis is essential to undertake an adequate treatment and, for this purpose, different methods have been tested. These include genetic test, hydrogen breath test (HBT), quick lactase test, and lactose tolerance test. HBT is the most used method because it is non-invasive, inexpensive, and highly sensitive and specific, as well as easy to perform. In clinical practice, the other methods are mainly used as HBT integration tests. There are also many therapeutic options. An appropriate intervention concerns the dietetic style, such as the consumption of lactose-free foods, but with nutritional characteristics comparable to dairy products. Other valid choices are represented by the use of exogenous enzymes, probiotics, prebiotics, the selection of milk containing specific types of beta-caseins. This review is intended to illustrate the diagnostic methods currently available and the possible therapeutic options for lactose intolerance.


Assuntos
Dieta , Intolerância à Lactose/diagnóstico , Intolerância à Lactose/terapia , Humanos , Lactase/administração & dosagem , Lactose/metabolismo , Intolerância à Lactose/dietoterapia , Intolerância à Lactose/fisiopatologia , Prebióticos , Probióticos
17.
Nutrients ; 13(4)2021 Apr 14.
Artigo em Inglês | MEDLINE | ID: mdl-33919766

RESUMO

Many patients with inflammatory bowel disease (IBD) restrict dairy products to control their symptoms. The aim of the study was to investigate the prevalence of lactose intolerance assessed with hydrogen breath test (H-BT) in IBD patients in clinical remission compared to a sex, age and BMI matched control population. We further detected the prevalence of three single nucleotide polymorphisms of the lactase (LCT) gene: the lactase non persistence LCT-13910 CC (wildtype) and the intermediate phenotype LCT-22018 CT and LCT-13910 AG; finally, we assess the correlation between genotype and H-BT. A total of 54 IBD patients and 69 control who underwent clinical evaluation, H-BT and genetic test were enrolled. H-BT was positive in 64.8% IBD patients and 62.3% control (p = 0.3). The wild-type genotype was found in 85.2% IBD patients while CT-22018, AG-13910 and CT-22018/AG-13910 polymorphisms were found in 9.3%, 1.8% and 3.7%. In the control group, the wild-type genotype, CT-22018, AG-13910 and CT-22018/AG-13910 polymorphisms were found in 87%, 5.8%, 5.8% and 1.4% of cases, respectively. Therefore, the wild-type and polymorphisms' prevalence did not differ between IBD population and control group (85.2% vs. 87%, p = 0.1) (14.8% vs. 13%, p = 0.7). The correlation between positive H-BT and genetic analysis showed that the wild-type genotype was associated with higher rate of lactose intolerance in the total population (OR 5.31, 95%CI 1.73-16.29, p = 0.003) and in the IBD (OR 7.61, 95%CI 1.36-42.7, p = 0.02). The prevalence of lactose intolerance in IBD patients did not differ from that of control. Despite suggestive symptoms, about 1/3 of IBD patients are not lactose intolerant, thus not needing "a priori" elimination diet. This may encourage a rationale and balanced dietary management in IBD.


Assuntos
Doenças Inflamatórias Intestinais/dietoterapia , Lactase/genética , Intolerância à Lactose/epidemiologia , Lactose/efeitos adversos , Adulto , Testes Respiratórios/métodos , Testes Genéticos/estatística & dados numéricos , Humanos , Hidrogênio/análise , Doenças Inflamatórias Intestinais/complicações , Lactase/metabolismo , Lactose/metabolismo , Intolerância à Lactose/complicações , Intolerância à Lactose/diagnóstico , Intolerância à Lactose/genética , Masculino , Pessoa de Meia-Idade , Polimorfismo de Nucleotídeo Único , Prevalência , Estudos Prospectivos , Adulto Jovem
18.
Food Chem ; 353: 129486, 2021 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-33735774

RESUMO

Motivated by the search for healthy alimentation and sustainable technological processes, this study aimed to produce a synbiotic composed of the prebiotic galacto-oligosaccharides (GOS) and the probiotic yeast Saccharomyces boulardii, simultaneously, using cheese whey permeate as substrate by enzymatic-fermentative method. A central composite rotatable design with center point was used to evaluate the influence of temperature and enzyme concentration in the GOS and S. boulardii production. The best condition to obtain the prebiotic was at 32 °C and enzyme concentration of 0.175% (w/w), providing 56.84 g L-1 of GOS concentration and Ln(3.59) 107 viable cells mL-1 of S. boulardii production. However, the condition that would favor the simultaneous production of GOS and S. boulardii studied through desirability function is 29.5 °C and 0.14% (w/w) of enzyme concentration. The simultaneous enzymatic-fermentative method showed promising results considering industrial application and can be easily incorporated into dairy production lines as functional food.


Assuntos
Galactose/metabolismo , Oligossacarídeos/metabolismo , Saccharomyces boulardii/crescimento & desenvolvimento , Simbióticos , Galactose/química , Lactose/metabolismo , Oligossacarídeos/química , Saccharomyces boulardii/metabolismo , Temperatura
19.
Am J Clin Nutr ; 113(4): 1009-1022, 2021 04 06.
Artigo em Inglês | MEDLINE | ID: mdl-33675341

RESUMO

BACKGROUND: Lack of robust estimates of human-milk nutrient composition and influential maternal factors, such as body composition, are barriers to informing nutrition policies and programs. OBJECTIVE: The objective was to understand the relation between maternal BMI and human-milk energy, fat, and/or total protein. METHODS: Four electronic databases (MEDLINE, Embase, CINAHL, and Web of Science) were searched. Outcomes assessed were human-milk energy (kcal/L), fat (g/L), and total protein (g/L) from mothers 1 to 6 mo postpartum. Studies with data on maternal BMI or weight and height that quantified human-milk energy, fat, or protein between 1 and 6 mo postpartum were eligible. Random-effects meta-regression weighted by the inverse of the study-level SE was completed for each of the 3 outcomes. The certainty of evidence for each outcome was assessed using the GRADE (Grading of Recommendations Assessment, Development, and Evaluation) approach. RESULTS: A total of 11,373 titles and abstracts were identified, and after full-text screening, 69 articles of 66 studies were included. Meta-regression results showed a positive association between maternal BMI and human-milk fat (ß: 0.56 g/L; 95% CI: 0.034, 1.1; P = 0.04; I2 = 93.7%, n = 63 datapoints). There was no significant association between maternal BMI and human-milk energy (ß: 3.9 kcal/L; 95% CI: -1.6, 9.5; P = 0.16, I2 = 93.3%, n = 40 datapoints) or total protein (ß: 0.13 g/L; 95% CI: -0.16, 0.41; P = 0.37, I2 = 99.1%, n = 40 datapoints). The certainty of evidence for human-milk energy was low and the certainty of evidence for fat and total protein was very low. CONCLUSIONS: Meta-regression analysis of available literature suggested an association between maternal BMI and human-milk fat between 1 and 6 mo postpartum. Future studies are needed to confirm the relation between maternal BMI; variation in human-milk energy, fat, and protein content; and the implications for child growth and development. This review is registered with International Prospective Register of Systematic Reviews (PROSPERO 2018 CRD42018098808) at https://www.crd.york.ac.uk/prospero/.


Assuntos
Índice de Massa Corporal , Gorduras/química , Leite Humano/química , Gorduras/metabolismo , Feminino , Humanos , Lactose/química , Lactose/metabolismo , Proteínas do Leite/química , Proteínas do Leite/metabolismo , Leite Humano/metabolismo
20.
Molecules ; 26(5)2021 Feb 25.
Artigo em Inglês | MEDLINE | ID: mdl-33668968

RESUMO

The unique chemical, optical, and electrical characteristics of nanoparticles make their utilization highly successful in every field of biological sciences as compared to their bulk counterpart. These properties arise as a result of their miniature size, which provides them an excellent surface area-to-volume ratio, inner structure, and shape, and hence increases their surface characteristics. Therefore, this study was undertaken to engineer gold nanoparticles (AuNPs) for improving their catalytic activity and stability in biotechnological processes. The characterization of AuNPs was performed by XRD, UV spectra, and TEM. The synthesized AuNPs were surface-modified by polyvinyl alcohol (PVA) for binding the enzyme in excellent yield. The developed immobilized enzyme system (PVA-AuNPs-ß-galactosidase) displayed pH optima at pH 7.0 and temperature optima at 40 °C. Moreover, the stability of PVA-AuNPs-ß-galactosidase was significantly enhanced at wider pH and temperature ranges and at higher galactose concentrations, in contrast to the free enzyme. ß-galactosidase bound to PVA-modified AuNPs exhibited greater operational activity, even after its sixth reuse. The developed nanosystem may prove useful in producing lactose-free dairy products for lactose-intolerant patients.


Assuntos
Laticínios , Ouro/química , Lactose/química , Nanopartículas Metálicas/química , beta-Galactosidase/química , Laticínios/análise , Estabilidade Enzimática , Enzimas Imobilizadas/química , Enzimas Imobilizadas/metabolismo , Ouro/metabolismo , Humanos , Concentração de Íons de Hidrogênio , Kluyveromyces/enzimologia , Lactose/metabolismo , Intolerância à Lactose/metabolismo , Teste de Tolerância a Lactose , Tamanho da Partícula , Propriedades de Superfície , Temperatura , beta-Galactosidase/metabolismo
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