RESUMO
BACKGROUND: Malnutrition and accessible high-quality protein food sources are two of the world's alimentary challenges. Edible insects are nowadays recognized as a possible functional food solution with lower environmental impacts and beneficial health effects. OBJECTIVE: In this context, the aim of the present study is to evaluate Madagascar cockroach (Gromphadorhina portentosa) flour supplementation effects on a malnourished mice model, considering its effects on metabolism, adiposity, and inflammatory liver profiles. METHOD: Male Swiss mice are divided into five groups and fed with experimental diets for eight weeks, including a standard diet (ST) ad libitum, AIN93 ad libitum (AIN), insect flour-enriched AIN93 (AIN+IM), AIN-40% feed restriction (AIN-FR), and insect flour-enriched AIN-40% of feed restriction (AIN-FR+IM). The metabolic profiles, adipose tissue, biochemical parameters, and liver IL-6 and IL-10 expression are evaluated. RESULTS: The main findings show a body weight and metabolism improvement followed by an increased recovery of the adipocyte area in the AIN-FR+IM group when compared to the AIN-FR malnourished group. Reduced hepatic IL-6 and increased IL-10 expression are also detected in the AIN-FR+IM group. CONCLUSION: The results show that insect flour supplementation enhances both body weight and adiposity gain/recovery. The results also show hepatic improvement of inflammatory markers.
Assuntos
Baratas , Desnutrição , Animais , Dieta , Suplementos Nutricionais , Farinha , Fígado , Madagáscar , Masculino , Camundongos , Patentes como AssuntoRESUMO
It is urgent the transition from a fossil fuel-based economy to a sustainable bioeconomy based on bioconversion technologies using renewable plant biomass feedstocks to produce high chemicals, bioplastics, and biofuels. ß-Glucosidases are key enzymes responsible for degrading the plant cell wall polymers, as they cleave glucan-based oligo- and polysaccharides to generate glucose. Monosaccharide-tolerant or -stimulated ß-glucosidases have been reported in the past decade. Here, we describe a novel mechanism of ß-glucosidase stimulation by glucose and xylose. The glycoside hydrolase 1 family ß-glucosidase from Thermotoga petrophila (TpBgl1) displays a typical glucose stimulation mechanism based on an increased Vmax and decreased Km in response to glucose. Through molecular docking and dynamics analyses, we mapped putative monosaccharide binding regions (BRs) on the surface of TpBgl1. Our results indicate that after interaction with glucose or xylose at BR1 site, an adjacent loop region assumes an extended conformation, which increases the entrance to the TpBgl1 active site, improving product formation. Biochemical assays with TpBgl1 BR1 mutants, TpBgl1D49A/Y410A and TpBgl1D49K/Y410H, resulted in decreasing and abolishing monosaccharide stimulation, respectively. These mutations also impaired the BR1 looping extension responsible for monosaccharide stimulation. This study provides a molecular basis for the rational design of ß-glucosidases for biotechnological applications.
Assuntos
Monossacarídeos/metabolismo , Thermotoga/enzimologia , beta-Glucosidase/química , beta-Glucosidase/metabolismo , Biocatálise , Domínio Catalítico , Glucose/metabolismo , Cinética , Simulação de Dinâmica Molecular , Proteínas Mutantes/química , Proteínas Mutantes/metabolismo , Ligação Proteica , Conformação Proteica , Xilose/metabolismoRESUMO
A bioreactor was built by means of immobilizing alpha-amylase from Aspergillus oryzae by encapsulation, through cryopolymerization of acrylamide monomers for the continuous starch hydrolysis. The starch hydrolysis was evaluated regarding pH, the concentration of immobilized amylase on cryogel, the concentration of starch solution and temperature. The maximum value for starch hydrolysis was achieved at pH 5.0, concentration of immobilized enzyme 111.44 mg amylase /gcryogel , concentration of starch solution 45 g/L and temperature of 35°C. The immobilized enzyme showed a conversion ratio ranging from 68.2 to 97.37%, depending on the pH and temperature employed. Thus, our results suggest that the alpha-amylase from A. oryzae immobilized on cryogel monoliths represents a potential process for industrial production of maltose from starch hydrolysis.
Assuntos
Reatores Biológicos , Criogéis/química , Enzimas Imobilizadas/metabolismo , Amido/metabolismo , alfa-Amilases/metabolismo , Aspergillus oryzae , Enzimas Imobilizadas/química , Proteínas Fúngicas/química , Proteínas Fúngicas/metabolismo , Concentração de Íons de Hidrogênio , Hidrólise , Maltose/metabolismo , Porosidade , Amido/análise , Amido/química , Temperatura , alfa-Amilases/químicaRESUMO
BACKGROUND: The renin-angiotensin system (RAS) is an important enzymatic system responsible for the regulation of biological functions, such as the arterial pressure, hydroelectrolytic control, vascular vasodilatation/vasoconstriction and more recently metabolic functions. OBJECTIVES: The aim of the present review is to discuss the associations between the gut microbiome and the renin-angiotensin system and the influence of their intimate relationship on the cardiovascular health. METHODS: A literature review of the main studies published regarding the relationship among the renin-angiotensin system, gut microbiota and cardiovascular health was performed. RESULTS: The association between the ACE2 and gut microbiota has been discussed. It is shown that the ACE2/Ang 1-7 axis modulates the immune response, influencing the microbiota composition, and thus being one of the causes for some diseases physiophatologies, such as diarrhea and intestinal inflammatory disease. CONCLUSION: The association between RAS and gut microbiota seems to have a strong influence on the genesis of cardiovascular diseases, through direct mechanisms, such as nerve stimulation, or indirectly on metabolic parameters, such as weight, adiposity and lipid profile.
Assuntos
Angiotensina I/metabolismo , Doenças Cardiovasculares/metabolismo , Doenças Cardiovasculares/microbiologia , Microbioma Gastrointestinal/imunologia , Fragmentos de Peptídeos/metabolismo , Peptidil Dipeptidase A/metabolismo , Sistema Renina-Angiotensina/imunologia , Enzima de Conversão de Angiotensina 2 , Animais , Doenças Cardiovasculares/tratamento farmacológico , Doenças Cardiovasculares/imunologia , HumanosRESUMO
BACKGROUND: During the past few years, the first industrial-scale cellulosic ethanol plants have been inaugurated. Although the performance of the commercial cellulase enzymes used in this process has greatly improved over the past decade, cellulases still represent a very significant operational cost. Depending on the region, transport of cellulases from a central production facility to a biorefinery may significantly add to enzyme cost. The aim of the present study was to develop a simple, cost-efficient cellulase production process that could be employed locally at a Brazilian sugarcane biorefinery. RESULTS: Our work focused on two main topics: growth medium formulation and strain improvement. We evaluated several Brazilian low-cost industrial residues for their potential in cellulase production. Among the solid residues evaluated, soybean hulls were found to display clearly the most desirable characteristics. We engineered a Trichoderma reesei strain to secrete cellulase in the presence of repressing sugars, enabling the use of sugarcane molasses as an additional carbon source. In addition, we added a heterologous ß-glucosidase to improve the performance of the produced enzymes in hydrolysis. Finally, the addition of an invertase gene from Aspegillus niger into our strain allowed it to consume sucrose from sugarcane molasses directly. Preliminary cost analysis showed that the overall process can provide for very low-cost enzyme with good hydrolysis performance on industrially pre-treated sugarcane straw. CONCLUSIONS: In this study, we showed that with relatively few genetic modifications and the right growth medium it is possible to produce considerable amounts of well-performing cellulase at very low cost in Brazil using T. reesei. With further enhancements and optimization, such a system could provide a viable alternative to delivered commercial cellulases.
RESUMO
Lipogenesis is the process by which fatty acids are synthesized. In metabolic syndrome, an insulin resistant state along with high plasma levels of free fatty acids (FFA) and hyperglycemia may contribute to the lipogenic process. The aim of the present study was to investigate the effects of oral administration of metformin on the expression of lipogenic genes and glycemic profile in mice fed with low-carbohydrate high-fat diet by evaluating their metabolic profile. SWISS male mice were divided into 4 groups (N = 7) that were fed with standard (ST), standard plus metformin (ST + MET), low-carbohydrate high-fat diet (LCHFD) and low-carbohydrate high-fat diet plus metformin (LCHFD + MET) (100 mg kg-1 diet) diets respectively. Food intake, body weight and blood parameters, such as glucose tolerance, insulin sensitivity, glucose, HDL-c, total cholesterol, triglycerides, ASL and ALT levels were assessed. Histological analyses were performed on hematoxylin and eosin-stained epididymal adipose tissue histological specimens. The expression levels of peroxisome proliferator-activated receptor (PPARγ), sterol regulatory element-binding protein 1 (SREBP1), fatty acid synthase (FAS) and acetyl-CoA carboxylase (ACC), were assessed by RT-PCR. This study showed that metformin decreased adipocyte area, body weight and food consumption in obese animals when compared to the standard group. Furthermore, the expression of lipogenic markers in adipose tissue were diminished in obese animals treated with metformin. This data showed that oral administration of metformin improved glucose and lipid metabolic parameters in white adipose tissue by reducing the expression of lipogenesis markers, suggesting an important clinical application of MET in treating obesity-related diseases in metabolic syndrome.
Assuntos
Biomarcadores/sangue , Hipoglicemiantes/administração & dosagem , Lipogênese/efeitos dos fármacos , Metformina/administração & dosagem , Obesidade/metabolismo , Acetil-CoA Carboxilase/genética , Tecido Adiposo/efeitos dos fármacos , Tecido Adiposo/metabolismo , Administração Oral , Animais , Peso Corporal/efeitos dos fármacos , Dieta com Restrição de Carboidratos , Dieta Hiperlipídica , Ingestão de Alimentos/efeitos dos fármacos , Ácido Graxo Sintases/genética , Regulação da Expressão Gênica/efeitos dos fármacos , Hipoglicemiantes/farmacologia , Masculino , Metformina/farmacologia , Camundongos , Camundongos Obesos , Obesidade/genética , PPAR gama/genética , Proteína de Ligação a Elemento Regulador de Esterol 1/genéticaRESUMO
Xylanases catalyze the hydrolysis of ß-1,4-linked xylosyl moieties from xylan chains, one of the most abundant hemicellulosic polysaccharides found in plant cell walls. These enzymes can exist either as single catalytic domains or as modular proteins composed of one or more carbohydrate-binding modules (CBMs) appended to the catalytic core. However, the molecular mechanisms governing the synergistic effects between catalytic domains and their CBMs are not fully understood. Thus, the goal of this study was to evaluate the functional effects of the fusion of a CBM belonging to family 6, which exhibits high affinity to xylan, with the GH11 xylanase from Bacillus subtilis, which does not have a CBM in its wild-type form. The wild-type enzyme (BsXyl11) and the chimeric protein (BsXyl11-CBM6) were heterologously produced in Escherichia coli and purified to homogeneity for biochemical characterization. The molecular fusion did not alter the pH and temperature dependence, but kinetic data revealed an increase of 65% in the catalytic efficiency of the chimeric enzyme. Furthermore, the BsXyl11-CBM6 chimera was used to supplement the commercial cocktail Accellerase® 1500 and improved the reducing sugar release by 17% from pretreated sugarcane bagasse. These results indicate that CBM6 can be used as a molecular tool to enhance the catalytic performance of endo-xylanases (GH11) and provide a new strategy for the development of optimized biocatalysts for biotechnological applications.
Assuntos
Endo-1,4-beta-Xilanases/química , Endo-1,4-beta-Xilanases/metabolismo , Xilanos/metabolismo , Bacillus subtilis/enzimologia , Bacillus subtilis/genética , Biotecnologia , Catálise , Domínio Catalítico , Celulose , Endo-1,4-beta-Xilanases/genética , Hidrólise , Cinética , Domínios Proteicos , Proteínas Recombinantes de Fusão/química , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/metabolismo , Saccharum , Especificidade por Substrato , Xilanos/químicaRESUMO
Xylan is an abundant plant cell wall polysaccharide and its reduction to xylose units for subsequent biotechnological applications requires a combination of distinct hemicellulases and auxiliary enzymes, mainly endo-xylanases and ß-xylosidases. In the present work, a bifunctional enzyme consisting of a GH11 endo-1,4-ß-xylanase fused to a GH43 ß-xylosidase, both from Bacillus subtilis, was designed taking into account the quaternary arrangement and accessibility to the substrate. The parental enzymes and the resulting chimera were successfully expressed in Escherichia coli, purified and characterized. Interestingly, the substrate cleavage rate was altered by the molecular fusion improving at least 3-fold the xylose production using specific substrates as beechwood xylan and hemicelluloses from pretreated biomass. Moreover, the chimeric enzyme showed higher thermotolerance with a positive shift of the optimum temperature from 35 to 50 °C for xylosidase activity. This improvement in the thermal stability was also observed by circular dichroism unfolding studies, which seems to be related to a gain of stability of the ß-xylosidase domain. These results demonstrate the superior functional and stability properties of the chimeric enzyme in comparison to individual parental domains, suggesting the molecular fusion as a promising strategy for enhancing enzyme cocktails aiming at lignocellulose hydrolysis.
Assuntos
Glicosídeo Hidrolases/metabolismo , Xilose/biossíntese , Bacillus subtilis/enzimologia , Bacillus subtilis/genética , Proteínas de Bactérias/química , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Biomassa , Biotecnologia , Dicroísmo Circular , Endo-1,4-beta-Xilanases/química , Endo-1,4-beta-Xilanases/genética , Endo-1,4-beta-Xilanases/metabolismo , Glicosídeo Hidrolases/química , Glicosídeo Hidrolases/genética , Hidrólise , Lignina/metabolismo , Modelos Moleculares , Polissacarídeos/metabolismo , Estrutura Quaternária de Proteína , Proteínas Recombinantes de Fusão/química , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/metabolismo , Especificidade por Substrato , Temperatura , Xilanos/metabolismo , Xilosidases/química , Xilosidases/genética , Xilosidases/metabolismoRESUMO
The ß-glucosidases are enzymes essential for several industrial applications, especially in the field of plant structural polysaccharides conversion into bioenergy and bioproducts. In a recent study, we have provided a biochemical characterization of two hyperthermostable ß-glucosidases from Thermotoga petrophila belonging to the families GH1 (TpBGL1) and GH3 (TpBGL3). Here, as part of a continuing investigation, the oligomeric state, the net charge, and the structural stability, at acidic pH, of the TpBGL1 and TpBGL3 were characterized and compared. Enzymatic activity is directly related to the balance between protonation and conformational changes. Interestingly, our results indicated that there were no significant changes in the secondary, tertiary and quaternary structures of the ß-glucosidases at temperatures below 80 °C. Furthermore, the results indicated that both the enzymes are stable homodimers in solution. Therefore, the observed changes in the enzymatic activities are due to variations in pH that modify protonation of the enzymes residues and the net charge, directly affecting the interactions with ligands. Finally, the results showed that the two ß-glucosidases displayed different pH dependence of thermostability at temperatures above 80 °C. TpBGL1 showed higher stability at pH 6 than at pH 4, while TpBGL3 showed similar stability at both pH values. This study provides a useful comparison of the structural stability, at acidic pH, of two different hyperthermostable ß-glucosidases and how it correlates with the activity of the enzymes. The information described here can be useful for biotechnological applications in the biofuel and food industries.