Isolation and characterization of an alpha-amylase gene in cassava (Manihot esculenta)

Model-assisted CRISPRi/a library screening reveals central carbon metabolic targets for enhanced recombinant protein production in yeast

Production of recombinant proteins is regarded as an important breakthrough in the field of biomedicine and industrial biotechnology. Due to the complexity of the protein secretory pathway and its tight interaction with cellular metabolism, the application of traditional metabolic engineering tools to improve recombinant protein production faces major challenges. A systematic approach is required to generate novel design principles for superior protein secretion cell factories. Here, we applied a proteome-constrained genome-scale protein secretory model of the yeast Saccharomyces cerevisiae (pcSecYeast) to simulate α-amylase production under limited secretory capacity and predict gene targets for downregulation and upregulation to improve α-amylase production. The predicted targets were evaluated using high-throughput screening of specifically designed CRISPR interference/activation (CRISPRi/a) libraries and droplet microfluidics screening. From each library, 200 and 190 sorted clones, respectively, were manually verified. Out of them, 50% of predicted downregulation targets and 34.6% predicted upregulation targets were confirmed to improve α-amylase production. By simultaneously fine-tuning the expression of three genes in central carbon metabolism, i.e. LPD1, MDH1, and ACS1, we were able to increase the carbon flux in the fermentative pathway and α-amylase production. This study exemplifies how model-based predictions can be rapidly validated via a high-throughput screening approach. Our findings highlight novel engineering targets for cell factories and furthermore shed light on the connectivity between recombinant protein production and central carbon metabolism.

Construction and investigation of multi-enzyme immobilized matrix for the production of HFCS

Enzymes are biological molecules that act as catalysts and speed up the biochemical reactions. The world's biotechnological ventures are development of enzyme productiveness, and advancement of novel techniques for thriving their shelf existence. Nowadays, the most burning questions in enzyme technology are how to improve the enzyme productivity and reuse them. The immobilization of enzymes provides an excellent scope to reuse the enzymes several times to increase productivity. The main aim of the present study is the establishment of an immobilized multi-enzyme bio-system engineering process for the production of High-fructose corn syrup (HFCS) with an industrial focus. In this study, multi-enzyme such as α-amylase, glucoamylase and glucose isomerase were immobilized in various support matrices like sodium alginate, sawdust, sugarcane bagasse, rice bran and combination of alginate with cellulosic materials. The activities of the immobilized multi-enzyme system for the production of HFCS from the starch solution were determined. The multi-enzyme immobilized in sodium alginate shows better fructose conversion than free enzyme. Among the support matrices, multi-enzyme immobilized in sawdust produced total 80.74 mg/mL of fructose from starch solution and it was able to be used in several production cycles. On the other hand, multi-enzyme immobilized in combination of sodium alginate and sawdust produced the maximum amount of fructose (total 84.82 mg/mL). The free enzyme produced 17.25 mg/mL of fructose from the starch solution in only a single cycle. In this study a new fixed bed immobilized multi-enzyme bioreactor system was developed for the production of HFCS directly from starch. This finding will create a new opportunity for the application of immobilized multi-enzyme systems in many sectors of industrial biotechnology.

Multicomponent diastereoselective synthesis of tetrahydropyridines as α-amylase and α-glucosidase enzymes inhibitors

Background: Researchers seeking new drug candidates to treat diabetes mellitus have been exploring bioactive molecules found in nature, particularly tetrahydropyridines (THPs). Methods: A library of THPs (1-31) were synthesized via a one-pot multicomponent reaction and investigated for their inhibition potential against α-glucosidase and α-amylase enzymes. Results: A nitrophenyl-substituted compound 5 with IC50 values of 0.15 ± 0.01 and 1.10 ± 0.04 μM, and a Km value of 1.30 mg/ml was identified as the most significant α-glucosidase and α-amylase inhibitor, respectively. Kinetic studies revealed the competitive mode of inhibition, and docking studies revealed that compound 5 binds to the enzyme by establishing hydrophobic and hydrophilic interactions and a salt bridge interaction with His279. Conclusion: These molecules may be a potential drug candidate for diabetes in the future.

SAR and lead optimization of (Z)-5-(4-hydroxy-3-methoxybenzylidene)-3-(2-morpholinoacetyl)thiazolidine-2,4-dione as a potential multi-target antidiabetic agent

In case of metabolic disorder like Diabetes mellitus (DM), a number of key enzymes are abnormally expressed and hence they might be excellent targets for antidiabetic drug design. Multi-target design strategy has recently attracted great attention to treat challenging diseases. We have previously reported a vanillin-thiazolidine-2,4-dione hybrid 3 as multitarget inhibitor of α-glucosidase, α-amylase, PTP-1B and DPP-4. The reported compound predominantly exhibited good in-vitro DPP-4 inhibition only. Current research describes the goal to optimize an early lead compound. The efforts were focused on enhancing the capability of manipulating multiple pathways at the same time for the treatment of diabetes. The central 5-benzylidinethiazolidine-2,4-dione for Lead compound (Z)-5-(4-hydroxy-3-methoxybenzylidene)-3-(2-morpholinoacetyl)thiazolidine-2,4-dione (Z-HMMTD) was left unchanged. While East and West moieties were altered by the introduction of different building blocks conceived by using a number of rounds of predictive docking studies performed on X-ray crystal structures of four target enzymes. This systematic SAR led to the syntheses of new potent multi-target antidiabetic compounds 47-49 and 55-57 with many fold increase in the in-vitro potency compared to Z-HMMTD. The potent compounds showed good in-vitro and in-vivo safety profile. Compound 56 emerged excellent as glucose-uptake promotor via hemi diaphragm of the rat. Moreover, the compounds demonstrated antidiabetic activity in STZ-induced diabetic animal model.

Hydrazinyl thiazole linked indenoquinoxaline hybrids: Potential leads to treat hyperglycemia and oxidative stress; Multistep synthesis, α-amylase, α-glucosidase inhibitory and antioxidant activities

A library of hydrazinyl thiazole-linked indenoquinoxaline hybrids 1-36 were synthesized via a multistep reaction scheme. All synthesized compounds were characterized by various spectroscopic techniques including EI-MS (electron ionization mass spectrometry) and ¹H NMR (nuclear magnetic resonance spectroscopy). Compounds 1-36 were evaluated for their inhibitory potential against α-amylase, and α-glucosidase enzymes. Among thirty-six, compounds 2, 9, 10, 13, 15, 17, 21, 22, 31, and 36 showed excellent inhibition against α-amylase (IC₅₀ = 0.3-76.6 μM) and α-glucosidase (IC₅₀ = 1.1-92.2 μM). Results were compared to the standard acarbose (IC₅₀ = 13.5 ± 0.2 μM). All compounds were also evaluated for their DPPH (1,1-diphenyl-2-picrylhydrazyl) radical scavenging activity and compounds 2, 9, 10, 17, 21, 31, and 36 showed (SC₅₀ = 7.58-125.86 μM) as compared to the standard ascorbic acid (SC₅₀ = 21.50 ± 0.18 μM). Among this library, compounds 9 and 10 with a hydroxy group on the phenyl rings and thiosemicarbazide bearing intermediate 21 were identified as the most potent inhibitors against α-amylase, and α-glucosidase enzymes. The remaining compounds were found to be moderately active. The molecular docking studies were conducted to understand the binding mode of active inhibitors and kinetic studies of the active compounds followed competitive modes of inhibition.

Common bean (Phaseolus vulgaris L.) α-amylase inhibitors as safe nutraceutical strategy against diabetes and obesity: An update review

Overweight and obesity are constantly increasing, not only in Western countries but also in low‐middle‐income ones. The decrease of both the intake of carbohydrates and their assimilation are among the main dietary strategies to counter these conditions. α‐Amylase, a key enzyme involved in the digestion of carbohydrates, is the target enzyme to reduce the absorption rate of carbohydrates. α‐Amylase inhibitors (α‐AIs) can be found in plants. The common bean, Phaseolus vulgaris is of particular interest due to the presence of protein‐based α‐AIs which, through a protein–protein interaction, reduce the activity of this enzyme. Here we describe the nature of the various types of common bean seed extracts, the type of protein inhibitors they contain, reviewing the recent Literature about their molecular structure and mechanism of action. We also explore the existing evidence (clinical trials conducted on both animals and humans) supporting the potential benefits of this protein inhibitors from P. vulgaris, also highlighting the urgent need of further studies to confirm the clinical efficacy of the commercial products. This work could contribute to summarize the knowledge and application of P. vulgaris extract as a nutraceutical strategy for controlling unwanted weight gains, also highlighting the current limitations.

Thiazolidinedione Derivatives: In Silico, In Vitro, In Vivo, Antioxidant and Anti-Diabetic Evaluation

This work aimed to synthesize a new antihyperglycemic thiazolidinedione based on the spectral data. The DFT\B3LYP\6-311G** level of theory was used to investigate the frontier molecular orbitals (FMOs), chemical reactivity and map the molecular electrostatic potentials (MEPs) to explain how the synthesized compounds interacted with the receptor. The molecular docking simulations into the active sites of PPAR-γ and α-amylase were performed. The in vitro potency of these compounds via α-amylase and radical scavenging were evaluated. The data revealed that compounds (4–6) have higher potency than the reference drugs. The anti-diabetic and anti-hyperlipidemic activities for thiazolidine-2,4-dione have been investigated in vivo using the alloxan-induced diabetic rat model along with the 30 days of treatment protocol. The investigated compounds didn’t show obvious reduction of blood glucose during pre-treatments compared to diabetic control, while after 30 days of treatments, the blood glucose level was lower than that of the diabetic control. Compounds (4–7) were able to regulate hyperlipidemia levels (cholesterol, triglyceride, high-density lipoproteins and low- and very-low-density lipoproteins) to nearly normal value at the 30th day.

Discovery Potent of Thiazolidinedione Derivatives as Antioxidant, α-Amylase Inhibitor, and Antidiabetic Agent

This work aimed to synthesize safe antihyperglycemic derivatives bearing thiazolidinedione fragment based on spectral data. The DFT theory discussed the frontier molecular orbitals (FMOs), chemical reactivity of compounds, and molecular electrostatic potential (MEP) to explain interaction between thiazolidinediones and the biological receptor. α-amylase is known as the initiator-hydrolysis of the of polysaccharides; therefore, developing α-amylase inhibitors can open the way for a potential diabetes mellitus drug. The molecular docking simulation was performed into the active site of PPAR-γ and α-amylase. We evaluated in vitro α-amylase's potency and radical scavenging ability. The compound 6 has the highest potency against α-amylase and radical scavenging compared to the reference drug and other members. They have been applied against anti-diabetic and anti-hyperlipidemic activity (in vivo) based on an alloxan-induced diabetic rat model during a 30-day treatment protocol. The most potent anti hyperglycemic members are 6 and 11 with reduction percentage of blood glucose level by 69.55% and 66.95%, respectively; compared with the normal control. Other members exhibited moderate to low anti-diabetic potency. All compounds showed a normal value against the tested biochemical parameters (CH, LDL, and HDL). The ADMET profile showed good oral bioavailability without any observed carcinogenesis effect.

Synthesis, α-Amylase Inhibitory Activity and Molecular Docking Studies of 2,4-Thiazolidinedione Derivatives

Introduction:

2,4-Thiazolidinedione and its derivatives exhibit a variety of pharmacological activities including antidiabetic, antiviral, antifungal, anti-inflammatory, anti-cancer and aldose reductase inhibitory activities. Keeping in mind the pharmacological potential of 2,4-Thiazolidinedione derivatives as antidiabetic agents, seven arylidene derivatives of 2,4-thiazolidinedione1(a-g)and four corresponding acetic acid derivatives 2(a-d)have been synthesized by a three-step procedure.

Methods:

All the synthesized compounds were characterized by elemental analysis, FTIR,1HNMR, and13CNMR and further screened for their α-amylase inhibitory potential.

Results:

All the compounds1(a-g)and2(a-d)showed varying degree of α-amylase inhibition, especially compound1c(IC50= 6.59μg/ml),1d(IC50=2.03μg/ml) and1g(IC50= 3.14μg/ml) displayed significantly potent α-amylase inhibition as compared to the standard acarbose (IC50= 8.26μg/ml). None of the acetic acid derivatives of 5-arylidene-2,4-thiazolidinedione showed prominent inhibitory activity. Docking results indicated that the best binding conformation was found inside the active site cleft of enzyme responsible for hydrolysis of carbohydrates.

Conclusion:

Therefore, it can be concluded that 2,4-thiazolidinedione derivatives can be used as effective lead molecules for the development of α-amylase inhibitors for the management of diabetes.

Inhibitory effects against α-glucosidase and α-amylase of the flavonoids-rich extract from Scutellaria baicalensis shoots and interpretation of structure-activity relationship of its eight flavonoids by a refined assign-score method

A flavonoids-rich extract of Scutellaria baicalensis shoots and its eight high content flavonoids were investigated for their inhibitory effects against α-glucosidase and α-amylase. Results show that abilities of the extract in inhibiting the two enzymes were obviously higher than those of acarbose. Moreover, inhibitory abilities of all the eight individual flavonoids against the two enzymes show exactly a same order (i.e., apigenin > baicalein > scutellarin > chrysin > apigenin-7-O-glucuronide > baicalin > chrysin-7-O-glucuronide > isocarthamidin-7-O-glucuronide), and their structure-activity relationship could be well-interpretated by the refined assign-score method. Furthermore, based on the inhibitory abilities and their contents in the extract, it was found that the eight flavonoids made predominant contributions, among which baicalein and scutellarin played roles as preliminary contributors, to overall inhibitory effects of the extract against the two enzymes. Beyond these, contributions of the eight flavonoids to the overall enzyme inhibitory activity were compared with those to the overall antioxidant activity characterized in our recent study, and it could be inferred that within the basic flavonoid structure the hydroxyl on C-4' of ring B was more effective than that on C-6 of ring A in enzyme inhibitory activities while they behaved inversely in antioxidant activities; scutellarin and apigenin contributed more to the overall enzyme inhibitory activity, and baicalin and scutellarin, to the overall antioxidant activity of the extract; and flavonoids of the extract, apart from directly inhibiting enzymes, might also be conducive to curing type 2 diabetes via scavenging various free radicals caused by increased oxidative stresses.

Characterization and Application of BiLA, a Psychrophilic α-Amylase from Bifidobacterium longum

In this study, a novel α-amylase was cloned from Bifidobacterium longum and named BiLA. The enzyme exhibited optimal activity at 20 °C and a pH value of 5.0. Kinetic analysis using various carbohydrate substrates revealed that BiLA had the highest k(cat/)K(m) value for amylose. Interestingly, analysis of the enzymatic reaction products demonstrated that BiLA specifically catalyzed the hydrolysis of oligosaccharides and starches up to G5 from the nonreducing ends. To determine whether BiLA can be used to generate slowly digestible starch (SDS), starch was treated with BiLA, and the kinetic parameters were analyzed using porcine pancreatic α-amylase (PPA) and amyloglucosidase (AMG). Compared to normal starch, BiLA-treated starch showed lower k(cat)/K(m) values with PPA and AMG, suggesting that BiLA is a potential candidate for the production of SDS.

The α-amylase and α-glucosidase inhibitory effects of Irish seaweed extracts

To date, numerous studies have reported on the antidiabetic properties of various plant extracts through inhibition of carbohydrate-hydrolysing enzymes. The objective of this research was to evaluate extracts of seaweeds for α-amylase and α-glucosidase inhibitory effects. Cold water and ethanol extracts of 15 seaweeds were initially screened and from this, five brown seaweed species were chosen. The cold water and ethanol extracts of Ascophyllum nodosum had the strongest α-amylase inhibitory effect with IC50 values of 53.6 and 44.7 μg/ml, respectively. Moreover, the extracts of Fucus vesiculosus Linnaeus were found to be potent inhibitors of α-glucosidase with IC50 values of 0.32 and 0.49 μg/ml. The observed effects were associated with the phenolic content and antioxidant activity of the extracts, and the concentrations used were below cytotoxic levels. Overall, our findings suggest that brown seaweed extracts may limit the release of simple sugars from the gut and thereby alleviate postprandial hyperglycaemia.

Novel allergens from ancient foods: Man e 5 from manioc (Manihot esculenta Crantz) cross reacts with Hev b 5 from latex

SCOPE

Manioc (Manihot esculenta) is a tuber mainly consumed in the Southern Hemisphere and used worldwide by food and chemistry industry. We aimed to recombinantly produce and characterize the first manioc allergen and evaluate its IgE reactivity in sera of Brazilian and Italian patients.

METHODS AND RESULTS

The molecule, termed Man e5, was expressed in E. coli, characterized by amino acid analysis, mass spectrometry, circular dichroism, HPLC, and dynamic light scattering. A tertiary structural model of the protein was produced using bioinformatics and susceptibility to pepsin digestion was analyzed in vitro. Based on its high content of charged residues, heat stability, flexibility and lack of secondary structure elements, the allergen was determined a member of the intrinsically disordered protein family. Brazilian patients were selected based on manioc allergy and Italians based on latex allergy and sensitization to Hev b 5.71% of Brazilians and 40% of Italians were in vitro IgE positive to Man e5. Cross-inhibition assays suggest a possible involvement of this allergen in the latex-fruit syndrome.

CONCLUSION

Man e5, the first purified allergen from manioc demonstrates IgE cross-reactivity with Hev b 5. Data suggest Hev b 5 might act as primary sensitizer and could therefore lead to allergic manifestations upon manioc consumption without prior exposition.

Application of microbial α-amylase in industry - A review

Amylases are one of the main enzymes used in industry. Such enzymes hydrolyze the starch molecules into polymers composed of glucose units. Amylases have potential application in a wide number of industrial processes such as food, fermentation and pharmaceutical industries. α-Amylases can be obtained from plants, animals and microorganisms. However, enzymes from fungal and bacterial sources have dominated applications in industrial sectors. The production of α-amylase is essential for conversion of starches into oligosaccharides. Starch is an important constituent of the human diet and is a major storage product of many economically important crops such as wheat, rice, maize, tapioca, and potato. Starch-converting enzymes are used in the production of maltodextrin, modified starches, or glucose and fructose syrups. A large number of microbial α-amylases has applications in different industrial sectors such as food, textile, paper and detergent industries. The production of α-amylases has generally been carried out using submerged fermentation, but solid state fermentation systems appear as a promising technology. The properties of each α-amylase such as thermostability, pH profile, pH stability, and Ca-independency are important in the development of fermentation process. This review focuses on the production of bacterial and fungal α-amylases, their distribution, structural-functional aspects, physical and chemical parameters, and the use of these enzymes in industrial applications.