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1.
J Agric Food Chem ; 68(3): 838-844, 2020 Jan 22.
Artigo em Inglês | MEDLINE | ID: mdl-31896254

RESUMO

Maltooligosaccharide-forming amylases (MFAses) are promising tools for a variety of food industry applications because they convert starch into functional maltooligosaccharides. The MFAse from Bacillus stearothermophilus STB04 (BstMFAse) is a thermostable enzyme that preferentially produces maltopentaose and maltohexaose. An X-ray crystal structure of the BstMFAse-acarbose complex suggested that mutation of glycine 109 would increase its maltohexaose specificity. Using site-directed mutagenesis, glycine 109 was replaced with several different amino acids. Mutant-containing asparagine (G109N), aspartic acid (G109D), and phenylalanine (G109F) produced 36.1, 42.4, and 39.0% maltohexaose from starch, respectively, which was greater than that produced by the wild-type (32.9%). These mutants also exhibited substantially altered oligosaccharide hydrolysis patterns in favor of maltohexaose production. Homology models suggested that the mutants form extra interactions with the substrate at subsite -6, which were responsible for the enhanced maltohexaose specificity of BstMFAse. The results of this study support the proposition that binding of the substrate's nonreducing end in the nonreducing end-subsite of the MFAse active center plays a crucial role in its product specificity.


Assuntos
Amilases/genética , Amilases/metabolismo , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Geobacillus stearothermophilus/enzimologia , Oligossacarídeos/metabolismo , Amilases/química , Proteínas de Bactérias/química , Sítios de Ligação , Geobacillus stearothermophilus/genética , Mutagênese Sítio-Dirigida , Oligossacarídeos/química , Engenharia de Proteínas , Amido/química , Amido/metabolismo , Especificidade por Substrato
2.
Arch Oral Biol ; 109: 104593, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31710967

RESUMO

OBJECTIVE: The aim of this study is to evaluate the short term effects of environmental temperature on saliva flow rate and composition. METHODS: In a cross-over study design 20 subjects (18-25 years old, 14 women, 6 men) were exposed in randomized order at different days to three temperatures (4 °C, 21 °C and 37 °C). Five minutes after a subject was exposed to the test temperature, collection of resting saliva was started for 5 min at the same temperature. Saliva flow rate, pH, viscosity, protein concentration, mucin 5B concentration and amylase activity were measured. RESULTS: Exposure to 4 °C resulted in an increase of the saliva flow rate (p < 0.01), protein output and amylase output (p < 0.001) compared to exposure to 21 °C or 37 °C. Although the figures for mucin 5B output at 4 °C were higher than at higher temperatures, this was not significant. There were no significant differences in the salivary mucin 5B concentration and viscosity between saliva samples collected at the indicated temperatures. CONCLUSIONS: Lowering of the temperature induces an increase in saliva flow rate, as well as protein and amylase output.


Assuntos
Amilases/metabolismo , Mucina-5B/metabolismo , Saliva/fisiologia , Proteínas e Peptídeos Salivares/metabolismo , Temperatura Ambiente , Adolescente , Adulto , Estudos Cross-Over , Feminino , Humanos , Masculino , Adulto Jovem
3.
Food Chem ; 305: 125269, 2020 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-31514049

RESUMO

Solid-state fermentation (SSF) is the preferred method of enhancing the phenolic content of oats, while scientific optimization for improving specific phenolic compounds is limited. In this study, sequential targeting of phenolic conversion in simultaneous hydrolysis and fermentation (SHF) of oats was investigated. The results revealed that SHF with adding cellulase at 0, 6 and 12 days could increase the total phenolic content by 4.4%, 67.8% and 59.1%, respectively, over that of SSF. The α-amylase and CMCase activity were highly correlated with the soluble and insoluble phenolic contents in SHF (-6 and -12) systems (r > 0.8, p < 0.05). Interestingly, the content of phenolic fraction, such as ferulic acid, was up-regulated, whereas sinapic acid was down-regulated. These results indicated that the phenolic conversion occurred in SHF, resulting in variation in DPPH and ABTS+ radical scavenging abilities. This research provided metabolic understanding of the optimization of phenolic compounds to increase the functional ingredient of oats.


Assuntos
Grão Comestível/metabolismo , Fermentação , Fenóis/análise , Amilases/análise , Amilases/metabolismo , Antioxidantes/análise , Avena/química , Avena/enzimologia , Avena/metabolismo , Celulase/análise , Celulase/metabolismo , Ácidos Cumáricos/análise , Grão Comestível/enzimologia , Hidrólise
4.
Food Chem ; 309: 125733, 2020 Mar 30.
Artigo em Inglês | MEDLINE | ID: mdl-31706677

RESUMO

Thermal treatment is an effective technique to modify the physiochemical properties of starch. However, investigation on the effect of repeated dry-heat treatment (RDHT) on the starch properties is limited. In this work, RDHT and continuous dry-heat treatment (CDHT) were conducted on normal maize starch. Both treatments increased pore no on the granule surface and facilitated the granule aggregation. The solubility and swelling power of normal maize starch were improved. The levels of slowly digestible starch (SDS) and resistant starch (RS) + SDS were increased. The structural characteristics, including crystallinity and short-range order, were impaired. The peak viscosity and thermal properties (To, Tp, Tc and ΔH) of starch paste were decreased. When comparing of CDHT samples with the same treating time, RDHT samples showed a lower crystallinity, a weaker thermal stability, a higher paste viscosity and a lower resistance to amylase. These results were useful for industrial application of thermal treatment on starch.


Assuntos
Amido/metabolismo , Zea mays/metabolismo , Amilases/metabolismo , Cristalização , Temperatura Alta , Solubilidade , Amido/química , Viscosidade
5.
Int J Mol Sci ; 20(19)2019 Oct 03.
Artigo em Inglês | MEDLINE | ID: mdl-31623309

RESUMO

Amylases are probably the best studied glycoside hydrolases and have a huge biotechnological value for industrial processes on starch. Multiple amylases from fungi and microbes are currently in use. Whereas bacterial amylases are well suited for many industrial processes due to their high stability, fungal amylases are recognized as safe and are preferred in the food industry, although they lack the pH tolerance and stability of their bacterial counterparts. Here, we describe three amylases, two of which have a broad pH spectrum extending to pH 8 and higher stability well suited for a broad set of industrial applications. These enzymes have the characteristic GH13 α-amylase fold with a central (ß/α)8-domain, an insertion domain with the canonical calcium binding site and a C-terminal ß-sandwich domain. The active site was identified based on the binding of the inhibitor acarbose in form of a transglycosylation product, in the amylases from Thamnidium elegans and Cordyceps farinosa. The three amylases have shortened loops flanking the nonreducing end of the substrate binding cleft, creating a more open crevice. Moreover, a potential novel binding site in the C-terminal domain of the Cordyceps enzyme was identified, which might be part of a starch interaction site. In addition, Cordyceps farinosa amylase presented a successful example of using the microseed matrix screening technique to significantly speed-up crystallization.


Assuntos
Amilases/química , Amilases/metabolismo , Fungos/enzimologia , Sítios de Ligação , Domínio Catalítico , Ativação Enzimática , Estabilidade Enzimática , Glucose/química , Glucose/metabolismo , Glicosilação , Concentração de Íons de Hidrogênio , Modelos Moleculares , Conformação Molecular , Ligação Proteica , Relação Estrutura-Atividade , alfa-Amilases/química , alfa-Amilases/metabolismo
6.
Chemosphere ; 237: 124561, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31549663

RESUMO

With the development of nanotechnology and increased nanomaterial application, TiO2 nanoparticles have been released into the aquatic environment, causing potential ecotoxicological effects on aquatic organisms. Ocean acidification caused by anthropogenic CO2 is one of the most common environmental stressors, occurring simultaneously with marine contaminants, e.g., nanoparticles. Marine bivalves can accumulate nanoparticles and their digestive functions may be affected. In this study, we investigated the potential influences of TiO2 nanoparticles on the digestive enzyme activities of marine mussels Mytilus coruscus under ocean acidification. Mussels were exposed to combined treatments with three concentrations of nano-TiO2 (0, 2.5, 10 mg/L) and two pH values (8.1, 7.3) for 14 days, and then recovered under ambient condition (pH 8.1 and no nanoparticle) for 7 days. Samples were taken on the 1st, 3rd, 7th, 14th, and 21st day, the digestive enzymes, including amylase, pepsin, trypsin, lipase, and lysozyme, were investigated. Our results showed that nano-TiO2 and low pH had negative effects on amylase, pepsin, trypsin, and lipase, while both of them led an increase in lysozyme activity. Nano-TiO2 showed greater effects on the digestive capacity of M. coruscus rather than low pH. Moreover, a recovery period of 7 days was not sufficient for these enzymes to fully recover.


Assuntos
Enzimas/metabolismo , Nanopartículas Metálicas/toxicidade , Mytilus/efeitos dos fármacos , Água do Mar/química , Titânio/toxicidade , Poluentes Químicos da Água/toxicidade , Amilases/metabolismo , Animais , Ecotoxicologia , Concentração de Íons de Hidrogênio , Lipase/metabolismo , Muramidase/metabolismo , Mytilus/fisiologia , Pepsina A/metabolismo , Tripsina/metabolismo , Poluentes Químicos da Água/química
7.
BMC Oral Health ; 19(1): 175, 2019 08 06.
Artigo em Inglês | MEDLINE | ID: mdl-31387562

RESUMO

BACKGROUND: Oral health is related to general health and one of the most prevalent chronic diseases is diabetes mellitus. Diabetes can have adverse effects on oral health and vice versa. Saliva analysis can be used as a non-invasive method to obtain information about diseases status like diabetes. The aim of present study was to evaluate the salivary immunoglobulin-A (s-IgA) and salivary amylase levels and their associations with oral-dental manifestations in patients with controlled and non-controlled type 2 diabetes. METHODS: This case-control study was carried out on 90 subjects who referred to the Diabetes Center of Shahid Bahonar Hospital, Kerman University of Medical Sciences, Kerman, Iran. Participants were divided into three groups: 1) uncontrolled diabetic patients (n = 30); 2) controlled diabetic patients (n = 30); and 3) healthy individuals (n = 30). Unstimulated salivary levels of I-A and amylase were measured. All participants underwent a dental and periodontal examination to explore the oral and dental manifestations. T-test, chi-square and ANOVA tests were used for data analysis in SPSS 18. RESULTS: Significant higher level of s-IgA was found in uncontrolled diabetic patients compared to controlled diabetic (P ≤ 0.0001) and the control group (P = 0.004). Moreover, the mean levels of s-amylase in uncontrolled patients was significantly higher compared to controlled diabetic (P = 0.01) and the control group (P ≤ 0.0001). Uncontrolled diabetic patients with oral candidiasis, erythematous candidiasis, abscesses, or xerostomia had higher s-IgA levels compared to the controlled diabetic participants. Moreover, uncontrolled diabetic patients with oral candidiasis or erythematous candidiasis showed a significant higher levels of s-amylase compared to controlled diabetic patients. Also, significant positive correlations were found between s-IgA and DMFT and s-IgA and PDI (r = 0.444, P = 0.014 and r = 0.386, P = 0.035, respectively). CONCLUSION: In conclusion, higher s-amylase and s-IgA concentrations may reflect oral-dental manifestations in T2DM. Moreover, the current findings suggest that s-amylase and s-IgA may serve as a complementary and alternative fluid in screening for diabetes mellitus.


Assuntos
Amilases/análise , Diabetes Mellitus Tipo 2/imunologia , Imunoglobulina A/análise , Saliva/enzimologia , Saliva/imunologia , Amilases/metabolismo , Estudos de Casos e Controles , Diabetes Mellitus Tipo 2/sangue , Diabetes Mellitus Tipo 2/metabolismo , Humanos , Irã (Geográfico)
8.
Diabetes Metab Syndr ; 13(4): 2601-2605, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31405682

RESUMO

AIMS: Diabetes Mellitus (DM) continues to burden millions of people worldwide. Early detection and effective diagnosis of DM are essential key strategies to reduce the impeding incidence of the disease and its complications. Thus, this study determined the potential utility of salivary glucose, amylase, calcium, and phosphorus as non-invasive diagnostic markers of DM. MATERIALS AND METHODS: A total of 80 participants were recruited and divided into two groups (non-diabetics and diabetics). Fasting blood samples and unstimulated saliva samples were collected and tested for glucose, amylase, calcium, and phosphorus. RESULTS: Mann-Whitney U test shows that salivary glucose and salivary amylase were significantly higher among diabetics than non-diabetics. In addition to this, the receiver operations characteristics (ROC) curve showed that salivary glucose (AUC = 0.811, p < 0.001) and amylase (AUC = 0.649, p = 0.03) has significant association with DM. CONCLUSION: Overall, only salivary glucose and amylase showed good potential in discriminating patients with diabetes from those without.


Assuntos
Amilases/metabolismo , Biomarcadores/metabolismo , Cálcio/metabolismo , Diabetes Mellitus Tipo 2/diagnóstico , Glucose/metabolismo , Fósforo/metabolismo , Saliva/metabolismo , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Estudos de Casos e Controles , Estudos Transversais , Diabetes Mellitus Tipo 2/metabolismo , Feminino , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Prognóstico , Curva ROC , Adulto Jovem
9.
Curr Microbiol ; 76(10): 1095-1104, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31270565

RESUMO

Fermented cereals are part of the main traditional diets of many people in Africa, usually obtained from artisanal production. The intensification of their manufacturing, responding to the consumers demand, requires a better control to ensure their sanitary, nutritional, and taste qualities, hence, the need of selecting accurate and safe starter cultures. In the present study, 48 lactic acid bacteria (LAB) strains, previously isolated from Algerian fermented wheat lemzeiet, were analyzed for different technological properties. 14 LAB strains, belonging to Pediococcus pentosaceus, Enterococcus faecium, Lactobacillus curvatus, Lactobacillus brevis, and Leuconostoc mesenteroides species, decreased rapidly the pH of the flour extract broth close to 4 or below. 91% of strains showed extracellular protease activity, but only 12% were amylolytics. 18 LAB strains inhibited or postponed the growth of three fungal targets Rhodotorula mucilaginosa UBOCC-A-216004, Penicillium verrucosum UBOCC-A-109221, and Aspergillus flavus UBOCC-A-106028. The strains belonging to Lactobacillus spp., Leuconostoc fallax, L. mesenteroides, and Weissella paramesenteroides were the most antifungal ones. Multiplex PCR for biogenic amines' production did not reveal any of the genes involved in the production of putrescine, histamine, and tyramine for 17 of the 48 strains. The obtained results provided several candidates for use as starter culture in the future production of lemzeiet.


Assuntos
/microbiologia , Microbiologia de Alimentos , Lactobacillales/isolamento & purificação , Lactobacillales/metabolismo , Triticum/microbiologia , Amilases/metabolismo , Antifúngicos/farmacologia , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Aminas Biogênicas/biossíntese , DNA Bacteriano/genética , Fermentação , Concentração de Íons de Hidrogênio , Lactobacillales/enzimologia , Lactobacillales/genética , Peptídeo Hidrolases/metabolismo
10.
Int J Biol Macromol ; 138: 394-402, 2019 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-31325505

RESUMO

To better understand structure-function relationships, an X-ray crystal structure of the maltooligosaccharide-forming amylase from Bacillus stearothermophilus STB04 (Bst-MFA) with bound acarbose has been determined at 2.2 Å. The structure revealed a classical three-domain fold stabilized by four calcium ions, in which CaI-CaIII form an unprecedented linear metal triad in the interior of domain B. Catalytic residues are deduced to be two aspartic acids and one glutamic acid (Asp234, Glu264, Asp331), and the acarbose is bound to surrounding amino acid residues, mainly through extensive hydrogen bonds. Furthermore, analysis of the structure indicates the existence of at least 8 subsites in Bst-MFA, six glycone sites (-6, -5, -4, -3, -2, -1) and two aglycone sites (+1, +2). Subsite +3 remains to be further explored. Sugar-binding subsites contribute to further presentation of the oligosaccharide-binding mode, which explains the product specificity of Bst-MFA to some extent. In addition, we propose a mechanism by which maltooligosaccharide-forming amylases produce particular maltooligosaccharide products, a result different from that seen with typical α-amylases. Finally, the three-dimensional structure of Bst-MFA complexed with acarbose provides the basis for further studies, designed to increase product specificity.


Assuntos
Amilases/química , Proteínas de Bactérias/química , Geobacillus stearothermophilus/enzimologia , Modelos Moleculares , Conformação Proteica , Sequência de Aminoácidos , Amilases/metabolismo , Proteínas de Bactérias/metabolismo , Sítios de Ligação , Domínio Catalítico , Ligações de Hidrogênio , Hidrólise , Simulação de Acoplamento Molecular , Simulação de Dinâmica Molecular , Oligossacarídeos/biossíntese , Oligossacarídeos/química , Ligação Proteica , Relação Estrutura-Atividade , Especificidade por Substrato
11.
Clin Lab ; 65(7)2019 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-31307179

RESUMO

BACKGROUND: Clinical Chemistry is the backbone of medical treatment, diagnostics, and prevention. The laborato-ries are trying to improve the quality and to reduce diagnostic errors and processing time and safeguard trace-ability of all laboratory procedures to ensure patient safety. Six sigma belongs to statistical quality control and provides a new methodology for measuring and improving process performance in laboratory. METHODS: Activities of AST, ALT, CK, LDH, Amy, and γ-GT were determined by standard kinetic methods on a Vitros 5600 biochemistry analyzer. Two daily quality controls (Verifier I and Verifier II) were run over 60 days. Total percent CV was calculated from routine daily QC. Between-instrument bias was also calculated from daily QC. RESULTS: The calculated sigma metrics for AST were 6.9 and 3.8; for ALT 9.3 and 5.6; for CK 6.6 and 5.3; LDH 5.2 and 5.2; for γ-GT 4.9 and 2.7; and for amylase 8.7 and 7.1. Analytical performance for AST, ALT, CK, LDH, and Amylase is world class. On the other hand, γ-GT analytical performance is poor. CONCLUSIONS: Six Sigma benefits from earlier quality management approaches that creates new challenges for medical laboratories.


Assuntos
Química Clínica/normas , Enzimas/sangue , Laboratórios/normas , Controle de Qualidade , Alanina Transaminase/sangue , Alanina Transaminase/metabolismo , Amilases/sangue , Amilases/metabolismo , Aspartato Aminotransferases/sangue , Aspartato Aminotransferases/metabolismo , Química Clínica/métodos , Creatinina , Erros de Diagnóstico/prevenção & controle , Enzimas/metabolismo , Humanos , Cinética , L-Lactato Desidrogenase/sangue , L-Lactato Desidrogenase/metabolismo , Monoéster Fosfórico Hidrolases/sangue , Monoéster Fosfórico Hidrolases/metabolismo , gama-Glutamiltransferase/sangue , gama-Glutamiltransferase/metabolismo
12.
Pancreatology ; 19(5): 646-652, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31301995

RESUMO

BACKGROUND & AIM: Ascites in patients with acute pancreatitis (AP) is understudied although recent literature hints at its evident role in the final outcome. This study was planned to study the characteristics of ascites in patients of AP and its effect on the disease course and outcome. METHODS: Consecutive patients of AP were studied and patients with or without ascites were evaluated for the baseline parameters and severity assessment. Ascites was quantified and fluid analyzed for its characteristics. Intraabdominal pressure (IAP) was monitored. The various outcome parameters were compared between the two groups of patients with and without ascites. RESULTS: Of the cohort of 213 patients, 82 (38.5%) developed ascites. Ascites group had significantly higher rates of organ failure (p = 0.001), necrosis (p=<0.001) and higher severity assessment scores. The ascites group had significantly longer hospital and ICU stay and higher ventilator days compared to the non-ascites group. Mortality was also higher in the ascites group (34.1% vs 8.45; p = 0.001). Majority of patients with ascites had moderate to gross ascites (75.6%), low serum ascites albumin gradient (87.8%) with low amylase levels (71.9%). Sub-group analysis in ascites group showed that patients with fatal outcome had higher rates of moderate to gross ascites, higher baseline IAP and lower reduction in IAP after 48 h. Moderate to gross ascites and grades of intra-abdominal hypertension (IAH) were significant predictors of mortality (AUC - 0.76). CONCLUSION: AP patients with ascites have a more severe disease with poorer outcome. Higher degrees of ascites and IAH grades are significant predictors of mortality.


Assuntos
Ascite/patologia , Pancreatite/patologia , Doença Aguda , Adulto , Amilases/metabolismo , Líquido Ascítico/química , Líquido Ascítico/patologia , Estudos de Coortes , Feminino , Humanos , Hipertensão Intra-Abdominal/etiologia , Hipertensão Intra-Abdominal/fisiopatologia , Tempo de Internação , Masculino , Pessoa de Meia-Idade , Pancreatite/mortalidade , Pancreatite/terapia , Paracentese , Valor Preditivo dos Testes , Resultado do Tratamento
13.
Arab J Gastroenterol ; 20(2): 86-90, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-31182342

RESUMO

BACKGROUND AND STUDY AIMS: pancreatic cysts are commonly found lesions and proper diagnosis is very important for planning further management. The study aims to evaluate the role of cyst fluid amylase and tumour markers as cancer antigen (CA 19-9) and carcinoembryonic antigen (CEA) in addition to mucin stain in diagnosing pancreatic cysts and differentiating malignant from benign lesions. PATIENTS AND METHODS: This prospective study was conducted on 184 patients diagnosed to have pancreatic cystic lesions from January 2013 to January 2018. Fluid analysis for CA 19-9, CEA, amylase, mucin stain and cytopathology were done. We compared these data with the final diagnosis based on histopathology after surgical resection, positive cytopathology and long period of follow up of the patients for at least 18 months. RESULTS: The highest AUC was that of cystic CEA with cut-off value of 160 ng/ml; it had a sensitivity of 60.4% and a specificity of 85%. The best cut-off value for cystic CA 19-9 was 1318 U/ml with a sensitivity of 64.1% and a specificity of 68.1%. The cut-off value of cyst amylase level was 5500 U/L, with 84.2% sensitivity and 37.1% specificity. The sensitivity of mucin stain in detecting mucinous cystic neoplasm was 85.45%, specificity was 86.05% with accuracy 85.87%. CONCLUSION: Cyst fluid analysis by investigating amylase, mucin, CA 19-9, CEA and EUS examination improves the diagnosis of different pancreatic cysts.


Assuntos
Cisto Pancreático/diagnóstico , Cisto Pancreático/metabolismo , Neoplasias Pancreáticas/diagnóstico , Neoplasias Pancreáticas/metabolismo , Adolescente , Adulto , Idoso , Amilases/metabolismo , Antígeno CA-19-9/metabolismo , Antígeno Carcinoembrionário/metabolismo , Criança , Diagnóstico Diferencial , Aspiração por Agulha Fina Guiada por Ultrassom Endoscópico , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Mucinas/metabolismo , Cisto Pancreático/patologia , Neoplasias Pancreáticas/patologia , Estudos Prospectivos , Curva ROC , Adulto Jovem
14.
Food Chem ; 297: 124885, 2019 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-31253299

RESUMO

Certain food properties (ex.: pH, polyphenolic composition) can inhibitdigestive amylases and thereby slow down starch digestion. Our aim was twofold. (1) To determine the impact of21 beverages and condiments (coffees, teas, wines, vinegars and lemon juice)on salivary and pancreatic amylolysis: inhibition ranged from 10% to 100%in our experimental conditions. (2) To investigate the effect of one black tea and lemon juice (selected for their strong inhibitory capacity) on starch hydrolysis during dynamicoro-gastro-intestinal digestion of bread. Compared to water (control), the effect of black tea was limited to a ≈20% reduction of released oligosaccharides during the intestinal phase. Lemon juice had a remarkable effect, completely interrupting gastric amylolysis by salivary amylase via a preliminary acidification of gastric contents. These results provide a strong biochemical rationale for the development of dietary strategies to improve the glycaemic impact of starch-rich meals which could be tested in vivo.


Assuntos
Amilases/metabolismo , Camellia sinensis/química , Sucos de Frutas e Vegetais/análise , Amido/metabolismo , Chá/química , Amilases/antagonistas & inibidores , Pão/análise , Camellia sinensis/metabolismo , Humanos , Hidrólise , Pâncreas/enzimologia , Saliva/enzimologia , Chá/metabolismo
15.
J Microbiol Biotechnol ; 29(6): 877-886, 2019 Jun 28.
Artigo em Inglês | MEDLINE | ID: mdl-31154743

RESUMO

Brewing with buckwheat as an ingredient has been proven to be successful in several previous studies. However, few studies have focused on the effects of buckwheat on the rutin content and antioxidant activity of beer. In order to develop a lager beer with high rutin content and desirable sensory characteristics, tartary buckwheat malt was used as a brewing adjunct. The results showed that the rutin-degrading enzyme was the key factor affecting the rutin content in the wort and beer. Compared to beer made using the common mashing method, the rutin content in the buckwheat beers produced using an improved mashing method was approximately 60 times higher. The total flavonoid contents in buckwheat beers also depended strongly on the mashing methods, ranging from 530.75 to 1,704.68 mg QE/l. The rutin-rich beers also showed better oxidative stability during forced-aging. Meanwhile, the buckwheat beers were found to be acceptable in terms of the main quality attributes, flavor, and taste.


Assuntos
Cerveja/análise , Fagopyrum/química , Rutina/química , Amilases/metabolismo , Antioxidantes/metabolismo , Fagopyrum/metabolismo , Fermentação , Flavonoides/química , Manipulação de Alimentos , Hordeum/química , Hordeum/metabolismo , Quercetina/química , Rutina/metabolismo , Plântula/química , Plântula/metabolismo , Sensação , Paladar
16.
Food Chem ; 295: 110-119, 2019 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-31174739

RESUMO

Amylose (AM) and amylopectin (AP) functionality during bread making was unravelled with a temperature-controlled time domain proton nuclear magnetic resonance (TD 1H NMR) toolbox. Fermented doughs from wheat flour containing starches with atypical AP chain length distribution and/or AM to AP ratio, or supplemented with Bacillus stearothermophilus α-amylase (BStA) were analyzed in situ during baking and cooling. The gelatinization temperature of starch logically depended on AP crystal stability. It was lower when starch contained a higher portion of short AP branches and higher when starch had higher AP content. During cooling, the onset temperature and extent of AM crystallization were positively related to starch AM content. BStA use resulted in slightly weakened starch networks and increased the starch polymers' mobility at the end of baking. That proton distributions evolved in a way corresponding to starch characteristics supports the suggested interpretation of NMR profiles during baking and cooling.


Assuntos
Amilopectina/química , Amilose/química , Farinha/análise , Triticum/metabolismo , Amilases/metabolismo , Pão/análise , Culinária/métodos , Geobacillus stearothermophilus/enzimologia , Espectroscopia de Prótons por Ressonância Magnética , Amido/química , Temperatura Ambiente
17.
J Biotechnol ; 302: 42-47, 2019 Aug 20.
Artigo em Inglês | MEDLINE | ID: mdl-31247237

RESUMO

Vitreoscilla hemoglobin (VHb), encoded by the Vitreoscilla hemoglobin gene (vgb), is highly effective at binding oxygen and delivering it to both prokaryotes and eukaryotes under hypoxic conditions. In this study, we introduced the vgb gene into shiitake mushrooms, and the mycelia of the transformatants grew faster. In particular, they spread into the solid substrate located in the lower part of the test tubes and bags where the oxygen was hypoxic and produced more ß-glucan and plant biomass degrading enzymes compared to the original strain. The maximum growth rate of the transformants was 8.5%-15.9% higher than that of the original strain on sawdust-based cultures in plastic bags. The laccase and amylase activities were 17.7%-40.3% and 16.7%-37.9% higher than that of the original strain, respectively. In addition, the ß-glucan contents of the transformant mycelia from the submerged fermentation were 12.9%-24.0% higher than that of the original strain. These results reveal that the expression of VHb in mushroom fungi promots the mycelial growth in solid-state cultures under the hypoxic condition as well as enhances ß-glucan and plant biomass degrading enzymes production.


Assuntos
Biomassa , Cogumelos Shiitake/metabolismo , Vitreoscilla/metabolismo , Amilases/metabolismo , Fermentação/fisiologia , Lacase/metabolismo
18.
Arch Microbiol ; 201(8): 1061-1073, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31123792

RESUMO

Plants are colonized by diverse microorganisms that can substantially impact their health and growth. Understanding bacterial diversity and the relationships between bacteria and phytopathogens may be key to finding effective biocontrol agents. We evaluated the bacterial community associated with anthracnose symptomatic and asymptomatic leaves of guarana, a typical tropical crop. Bacterial communities were assessed through culture-independent techniques based on extensive 16S rRNA sequencing, and cultured bacterial strains were evaluated for their ability to inhibit the growth of Colletotrichum sp. as well as for enzyme and siderophore production. The culture-independent method revealed that Proteobacteria was the most abundant phylum, but many sequences were unclassified. The emergence of anthracnose disease did not significantly affect the bacterial community, but the abundance of the genera Acinetobacter, Pseudomonas and Klebsiella were significantly higher in the symptomatic leaves. In vitro growth of Colletotrichum sp. was inhibited by 11.38% of the cultured bacterial strains, and bacteria with the highest inhibition rates were isolated from symptomatic leaves, while asymptomatic leaves hosted significantly more bacteria that produced amylase and polygalacturonase. The bacterial isolate Bacillus sp. EpD2-5 demonstrated the highest inhibition rate against Colletotrichum sp., whereas the isolates EpD2-12 and FD5-12 from the same genus also had high inhibition rates. These isolates were also able to produce several hydrolytic enzymes and siderophores, indicating that they may be good candidates for the biocontrol of anthracnose. Our work demonstrated the importance of using a polyphasic approach to study microbial communities from plant diseases, and future work should focus on elucidating the roles of culture-independent bacterial communities in guarana anthracnose disease.


Assuntos
Antibiose/fisiologia , Agentes de Controle Biológico/isolamento & purificação , Colletotrichum/crescimento & desenvolvimento , Paullinia/microbiologia , Proteobactérias/isolamento & purificação , Acinetobacter/classificação , Acinetobacter/genética , Acinetobacter/isolamento & purificação , Amilases/metabolismo , Antracose/microbiologia , Bacillus/classificação , Bacillus/genética , Bacillus/isolamento & purificação , Klebsiella/classificação , Klebsiella/genética , Klebsiella/isolamento & purificação , Microbiota , Doenças das Plantas/microbiologia , Folhas de Planta/microbiologia , Poligalacturonase/metabolismo , Proteobactérias/classificação , Proteobactérias/genética , Pseudomonas/classificação , Pseudomonas/genética , Pseudomonas/isolamento & purificação , RNA Ribossômico 16S/genética , Floresta Úmida , Sideróforos/metabolismo
19.
Fish Physiol Biochem ; 45(4): 1309-1320, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-31089992

RESUMO

An experiment was carried out to assess the effect of replacing fishmeal with mopane worm meal in the diet of Clarias gariepinus. Juvenile C. gariepinus weighing 67.04 ± 3 g were stocked in 15 rectangular concrete tanks connected to a recirculating system. Five diets denoted D1, D2, D3, D4 and D5 were formulated to replace fishmeal with mopane worm meal at 0, 10, 20, 40 and 60%. Triplicate groups of C. gariepinus were randomly assigned to each diet at a stocking density of 100 fish per tank. The fish were fed to apparent satiation twice daily for 51 days. All growth performance indices declined with higher mopane worm inclusion levels. Specific growth rate (SGR) declined from 1.85%/day in the control diet to 1.43%/day in diet 5. Protein efficiency ratio (PER) also declined from 25.27% in the control diet to 19.30% in diet 5. Apparent digestibility coefficient (ADC) followed a similar pattern declining from 92.2% in the control diet to 87.1% in diet 5. Both amylase and protease activity in the stomach increased with higher mopane worm inclusion levels. Despite the increased enzyme activity in the stomach, SGR declined. The decline in SGR was attributed to high acid detergent fibre (ADF 58.4 g/kg) and chitin in the mopane worm diets. Lipase and chitinase did not show any discernible pattern with high mopane worm inclusion levels in the stomach. In the intestines, protease, lipase and chitinase did not show any discernible pattern with high mopane worm inclusion levels. Consequently, the relationship between SGR and all these enzymes was weak. However, amylase activity declined with higher mopane worm inclusion levels in the intestines, and this resulted in decreased SGR (r2 = 0.6722). The negative effects of mopane worm meal were further confirmed by the increase in liver degradation scores at high mopane worm inclusion levels. The liver degradation score increased from 1.12 in the control to 2.46 in diet 5.


Assuntos
Ração Animal , Peixes-Gato , Dieta/veterinária , Larva , Mariposas , Amilases/metabolismo , Animais , Peixes-Gato/anatomia & histologia , Peixes-Gato/crescimento & desenvolvimento , Peixes-Gato/metabolismo , Quitinases/metabolismo , Hepatócitos/patologia , Mucosa Intestinal/enzimologia , Lipase/metabolismo , Peptídeo Hidrolases/metabolismo , Estômago/enzimologia
20.
Molecules ; 24(9)2019 Apr 30.
Artigo em Inglês | MEDLINE | ID: mdl-31052207

RESUMO

Intracellular polysulfide could regulate the redox balance via its anti-oxidant activity. However, the existence of polysulfide in biological fluids still remains unknown. Recently, we developed a quantitative analytical method for polysulfide and discovered that polysulfide exists in plasma and responds to oxidative stress. In this study, we confirmed the presence of polysulfide in other biological fluids, such as semen and nasal discharge. The levels of polysulfide in these biological fluids from healthy volunteers (n = 9) with identical characteristics were compared. Additionally, the circadian rhythm of plasma polysulfide was also investigated. The polysulfide levels detected from nasal discharge and seminal fluid were approximately 400 and 600 µM, respectively. No correlation could be found between plasma polysulfide and the polysulfide levels of tear, saliva, and nasal discharge. On the other hand, seminal polysulfide was positively correlated with plasma polysulfide, and almost all polysulfide contained in semen was found in seminal fluid. Intriguingly, saliva and seminal polysulfide strongly correlated with salivary amylase and sperm activities, respectively. These results provide a foundation for scientific breakthroughs in various research areas like infertility and the digestive system process.


Assuntos
Amilases/metabolismo , Espermatozoides/fisiologia , Sulfetos/metabolismo , Adulto , Fatores Etários , Biomarcadores , Líquidos Corporais , Índice de Massa Corporal , Ritmo Circadiano , Feminino , Humanos , Masculino , Proteínas/metabolismo , Fatores Sexuais , Contagem de Espermatozoides , Motilidade Espermática , Adulto Jovem
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