Health Impact and Therapeutic Manipulation of the Gut Microbiome.

Recent advances in microbiome studies have revealed much information about how the gut virome, mycobiome, and gut bacteria influence health and disease. Over the years, many studies have reported associations between the gut microflora under different pathological conditions. However, information about the role of gut metabolites and the mechanisms by which the gut microbiota affect health and disease does not provide enough evidence.

Overexpression and characterization of an extremely thermostable maltogenic amylase, with an optimal temperature of 100 degrees C, from the hyperthermophilic archaeon Staphylothermus marinus.

A gene encoding a hyperthermostable maltogenic amylase of Staphylothermus marinus (SMMA) was cloned and overexpressed in Escherichia coli. SMMA consisted of 696 amino acids with a predicted molecular mass of 82.5 kDa.

Identification of a naturally-occurring 8-[alpha-D-glucopyranosyl-(1-->6)-beta-D-glucopyranosyl]daidzein from cultivated kudzu root.

Introduction: Kudzu root (Radix puerariae) is a rich source of isoflavones that are effective in preventing osteoporosis, heart disease and symptoms associated with menopause. The major isoflavonoids in kudzu root extracts were reported as puerarin, daidzin and daidzein. Recently, an unknown isoflavonoid (compound 1) was detected from one-year-old kudzu root cultivated in Vietnam.

Characterization of a novel debranching enzyme from Nostoc punctiforme possessing a high specificity for long branched chains.

A novel debranching enzyme from Nostoc punctiforme PCC73102 (NPDE) exhibits hydrolysis activity toward both alpha-(1,6)- and alpha-(1,4)-glucosidic linkages. The action patterns of NPDE revealed that branched chains are released first, and the resulting maltooligosaccharides are then hydrolyzed. Analysis of the reaction with maltooligosaccharide substrates labeled with (14)C-glucose at the reducing end shows that NPDE specifically liberates glucose from the reducing end.

Changes in the catalytic properties of Pyrococcus furiosus thermostable amylase by mutagenesis of the substrate binding sites.

Pyrococcus furiosus thermostable amylase (TA) is a cyclodextrin (CD)-degrading enzyme with a high preference for CDs over maltooligosaccharides. In this study, we investigated the roles of four residues (His414, Gly415, Met439, and Asp440) in the function of P. furiosus TA by using site-directed mutagenesis and kinetic analysis.

Modulation of substrate preference of thermus maltogenic amylase by mutation of the residues at the interface of a dimer.

To elucidate the relationship between the substrate size and geometric shape of the catalytic site of Thermus maltogenic amylase, Gly50, Asp109, and Val431, located at the interface of the dimer, were replaced with bulky amino acids. The k(cat)/K(m) value of the mutant for amylose increased significantly, whereas that for amylopectin decreased as compared to that of the wild-type enzyme. Thus, the substituted bulky amino acid residues modified the shape of the catalytic site, such that the ability of the enzyme to distinguish between small and large molecules like amylose and amylopectin was enhanced.

Enzymatic preparation of maltohexaose, maltoheptaose, and maltooctaose by the preferential cyclomaltooligosaccharide (cyclodextrin) ring-opening reaction of Pyrococcus furiosus thermostable amylase.

Specific-length maltooligosaccharides, particularly maltohexaose, maltoheptaose, and maltooctaose, were prepared from cyclomaltooligosaccharides (cyclodextrins, CDs) by the preferential cyclodextrin ring-opening reaction of an amylolytic enzyme from Pyrococcus furiosus. The enzyme primarily produces maltohexaose, maltoheptaose, and maltooctaose by hydrolyzing alpha-, beta-, and gamma-CD, respectively. This study aims to develop a high-efficiency synthesis of specific maltooligosaccharides at high-purity.