Publications by authors named "Takane Katayama"

98 Publications

(+)-Sesamin, a sesame lignan, is a potent inhibitor of gut bacterial tryptophan indole-lyase that is a key enzyme in chronic kidney disease pathogenesis.

Biochem Biophys Res Commun 2022 Jan 26;590:158-162. Epub 2021 Dec 26.

Department of Biomolecular Engineering, Graduate School of Engineering, Tohoku University, Sendai, Japan. Electronic address:

The progression of chronic kidney disease (CKD) increases the risks of cardiovascular morbidity and end-stage kidney disease. Indoxyl sulfate (IS), which is derived from dietary l-tryptophan by the action of bacterial l-tryptophan indole-lyase (TIL) in the gut, serves as a uremic toxin that exacerbates CKD-related kidney disorder. A mouse model previously showed that inhibition of TIL by 2-aza-l-tyrosine effectively reduced the plasma IS level, causing the recovery of renal damage. In this study, we found that (+)-sesamin and related lignans, which occur abundantly in sesame seeds, inhibit intestinal bacteria TILs. Kinetic studies revealed that (+)-sesamin and sesamol competitively inhibited Escherichia coli TIL (EcTIL) with K values of 7 μM and 14 μM, respectively. These K values were smaller than that of 2-aza-l-tyrosine (143 μM). Molecular docking simulation of (+)-sesamin- (or sesamol-)binding to EcTIL predicted that these inhibitors potentially bind near the active site of EcTIL, where the cofactor pyridoxal 5'-phosphate is bound, consistent with the kinetic results. (+)-Sesamin is a phytochemical with a long history of consumption and is generally regarded as safe. Hence, dietary supplementation of (+)-sesamin encapsulated in enteric capsules could be a promising mechanism-based strategy to prevent CKD progression. Moreover, the present findings would provide a new structural basis for designing more potent TIL inhibitors for the development of mechanism-based therapeutic drugs to treat CKD.
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http://dx.doi.org/10.1016/j.bbrc.2021.12.088DOI Listing
January 2022

Thermococcus sp. KS-1 PPIase as a fusion partner improving soluble production of aromatic amino acid decarboxylase.

AMB Express 2021 Dec 27;11(1):178. Epub 2021 Dec 27.

Research Institute for Bioresources and Biotechnology, Ishikawa Prefectural University, Nonoichi, Ishikawa, 921-8836, Japan.

Peptidyl-prolyl cis-trans isomerase (PPIase, EC 5.2.1.8) catalyzes the racemization reaction of proline residues on a polypeptide chain. This enzyme is also known to function as a molecular chaperon to stabilize protein conformation during the folding process. In this study, we noted FK506 binding protein (FKBP)-type PPIase from a hyperthemophilic archaeon Thermococcus sp. strain KS-1 (PPIase ) to improve the solubility of Pseudomonas putida aromatic amino acid decarboxylase (AADC) that is an indispensable enzyme for fermentative production of plant isoquinoline alkaloids. AADC fused N-terminally with the PPIase (PPIase -AADC), which was synthesized utilizing Escherichia coli host, showed improved solubility and, consequently, the cell-free extract from the recombinant strain exhibited 2.6- to 3.4-fold elevated AADC activity than that from the control strain that expressed the AADC gene without PPIase . On the other hand, its thermostability was slightly decreased by fusing PPIase . The recombinant E. coli cells expressing the PPIase -AADC gene produced dopamine and phenylethylamine from L-dopa and phenylalanine by two- and threefold faster, respectively, as compared with the control strain. We further demonstrated that the efficacy of PPIase -AADC in solubility and activity enhancement was a little but obviously higher than that of AADC fused N-terminally with NusA protein, which has been assumed to be the most effective protein solubilizer. These results suggest that PPIase can be used as one of the best choices for producing heterologous proteins as active forms in E. coli.
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http://dx.doi.org/10.1186/s13568-021-01340-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8712285PMC
December 2021

SGLT-1-specific inhibition ameliorates renal failure and alters the gut microbial community in mice with adenine-induced renal failure.

Physiol Rep 2021 12;9(24):e15092

Department of Medical Science, Tohoku University Graduate School of Biomedical Engineering, Sendai, Japan.

Sodium-dependent glucose cotransporters (SGLTs) have attracted considerable attention as new targets for type 2 diabetes mellitus. In the kidney, SGLT2 is the major glucose uptake transporter in the proximal tubules, and inhibition of SGLT2 in the proximal tubules shows renoprotective effects. On the other hand, SGLT1 plays a role in glucose absorption from the gastrointestinal tract, and the relationship between SGLT1 inhibition in the gut and renal function remains unclear. Here, we examined the effect of SGL5213, a novel and potent intestinal SGLT1 inhibitor, in a renal failure (RF) model. SGL5213 improved renal function and reduced gut-derived uremic toxins (phenyl sulfate and trimethylamine-N-oxide) in an adenine-induced RF model. Histological analysis revealed that SGL5213 ameliorated renal fibrosis and inflammation. SGL5213 also reduced gut inflammation and fibrosis in the ileum, which is a primary target of SGL5213. Examination of the gut microbiota community revealed that the Firmicutes/Bacteroidetes ratio, which suggests gut dysbiosis, was increased in RF and SGL5213 rebalanced the ratio by increasing Bacteroidetes and reducing Firmicutes. At the genus level, Allobaculum (a major component of Erysipelotrichaceae) was significantly increased in the RF group, and this increase was canceled by SGL5213. We also measured the effect of SGL5213 on bacterial phenol-producing enzymes that catalyze tyrosine into phenol, following the reduction of phenyl sulfate, which is a novel marker and a therapeutic target for diabetic kidney disease DKD. We found that the enzyme inhibition was less potent, suggesting that the change in the microbial community and the reduction of uremic toxins may be related to the renoprotective effect of SGL5213. Because SGL5213 is a low-absorbable SGLT1 inhibitor, these data suggest that the gastrointestinal inhibition of SGLT1 is also a target for chronic kidney diseases.
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http://dx.doi.org/10.14814/phy2.15092DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8683788PMC
December 2021

Diversification of a fucosyllactose transporter within the genus .

Appl Environ Microbiol 2021 Nov 3:AEM0143721. Epub 2021 Nov 3.

Graduate School of Biostudies, Kyoto University, Kyoto 606-8502, Japan.

Human milk oligosaccharides (HMOs), which are natural bifidogenic prebiotics, were recently commercialized to fortify formula milk. However, HMO-assimilation phenotypes of bifidobacteria vary by species and strain, which has not been fully linked to strain genotype. We have recently shown that specialized uptake systems, particularly for the internalization of major HMOs (fucosyllactose (FL)), are associated with the formation of a bifidobacteria-rich gut microbial community. Phylogenetic analysis has revealed that FL transporters have diversified into two clades harboring four clusters within the genus, but the underpinning functional diversity associated with this divergence remains underexplored. In this study, we examined the HMO-consumption phenotypes of two bifidobacterial species, subspecies and , which both possess FL binding proteins that belong to phylogenetic clusters with unknown specificities. Growth assays, heterologous gene expression experiments, and HMO-consumption analysis showed that the FL transporter type from subspecies JCM 15439 conferred a novel HMO-uptake pattern that includes the complex fucosylated HMOs (lacto-fucopentaose II and lacto-difucohexaose I/II). Further genomic landscape analyses of FL transporter-positive bifidobacterial strains revealed that H-antigen or Lewis antigen-specific fucosidase gene(s) and FL transporter specificities were largely aligned. These results suggest that bifidobacteria have acquired FL transporters along with the corresponding gene sets necessary to utilize the imported HMOs. Our results provide insight into the species- and strain-dependent adaptation strategies of bifidobacteria to HMO-rich environments. The gut of breastfed infants is generally dominated by health-promoting bifidobacteria. Human milk oligosaccharides (HMOs) from breastmilk selectively promote the growth of specific taxa such as bifidobacteria, thus forming an HMO-mediated, host-microbe symbiosis. While the co-evolution of humans and bifidobacteria has been proposed, the underpinning adaptive strategies employed by bifidobacteria require further research. Here, we analyzed the divergence of the critical fucosyllactose (FL) HMO transporter within . We have shown that the diversification of the solute-binding proteins of the FL-transporter led to uptake specificities of fucosylated sugars ranging from simple trisaccharides to complex hexasaccharides. This transporter and the congruent acquisition of the necessary intracellular enzymes allows for bifidobacteria to import different types of HMOs in a predictable and strain-dependent manner. These findings explain the adaptation and proliferation of bifidobacteria in the competitive and HMO-rich infant gut environment and enable accurate specificity annotation of transporters from metagenomic data.
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http://dx.doi.org/10.1128/AEM.01437-21DOI Listing
November 2021

Bifidobacterium species associated with breastfeeding produce aromatic lactic acids in the infant gut.

Nat Microbiol 2021 11 21;6(11):1367-1382. Epub 2021 Oct 21.

National Food Institute, Technical University of Denmark, Kgs. Lyngby, Denmark.

Breastfeeding profoundly shapes the infant gut microbiota, which is critical for early life immune development, and the gut microbiota can impact host physiology in various ways, such as through the production of metabolites. However, few breastmilk-dependent microbial metabolites mediating host-microbiota interactions are currently known. Here, we demonstrate that breastmilk-promoted Bifidobacterium species convert aromatic amino acids (tryptophan, phenylalanine and tyrosine) into their respective aromatic lactic acids (indolelactic acid, phenyllactic acid and 4-hydroxyphenyllactic acid) via a previously unrecognized aromatic lactate dehydrogenase (ALDH). The ability of Bifidobacterium species to convert aromatic amino acids to their lactic acid derivatives was confirmed using monocolonized mice. Longitudinal profiling of the faecal microbiota composition and metabolome of Danish infants (n = 25), from birth until 6 months of age, showed that faecal concentrations of aromatic lactic acids are correlated positively with the abundance of human milk oligosaccharide-degrading Bifidobacterium species containing the ALDH, including Bifidobacterium longum, B. breve and B. bifidum. We further demonstrate that faecal concentrations of Bifidobacterium-derived indolelactic acid are associated with the capacity of these samples to activate in vitro the aryl hydrocarbon receptor (AhR), a receptor important for controlling intestinal homoeostasis and immune responses. Finally, we show that indolelactic acid modulates ex vivo immune responses of human CD4 T cells and monocytes in a dose-dependent manner by acting as an agonist of both the AhR and hydroxycarboxylic acid receptor 3 (HCA). Our findings reveal that breastmilk-promoted Bifidobacterium species produce aromatic lactic acids in the gut of infants and suggest that these microbial metabolites may impact immune function in early life.
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http://dx.doi.org/10.1038/s41564-021-00970-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8556157PMC
November 2021

An oral cancer vaccine using a vector suppresses tumor growth in a syngeneic mouse bladder cancer model.

Mol Ther Oncolytics 2021 Sep 25;22:592-603. Epub 2021 Aug 25.

Laboratory of Translational Research for Biologics, Department of Advanced Medical Science, Kobe University Graduate School of Science, Technology and Innovation, Kusunoki-cho, Chuo-ku, Kobe 650-0017, Japan.

Cancer immunotherapy using immune-checkpoint inhibitors (ICIs) such as PD-1/PD-L1 inhibitors has been well established for various types of cancer. Monotherapy with ICIs, however, can achieve a durable response in only a subset of patients. There is a great unmet need for the ICI-resistant-tumors. Since patients who respond to ICIs should have preexisting antitumor T cell response, combining ICIs with cancer vaccines that forcibly induce an antitumor T cell response is a reasonable strategy. However, the preferred administration sequence of the combination of ICIs and cancer vaccines is unknown. In this study, we demonstrated that combining an oral WT1 cancer vaccine using a vector and following anti-PD-1 antibody treatment eliminated tumor growth in a syngeneic mouse model of bladder cancer. This vaccine induced T cell responses specific to multiple WT1 epitopes through the gut immune system. Moreover, in a tumor model poorly responsive to an initial anti-PD-1 antibody, this vaccine alone significantly inhibited the tumor growth, whereas combination with continuous anti-PD-1 antibody could not inhibit the tumor growth. These results suggest that this oral cancer vaccine alone or as an adjunct to anti-PD-1 antibody could provide a novel treatment option for patients with advanced urothelial cancer including bladder cancer.
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http://dx.doi.org/10.1016/j.omto.2021.08.009DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8449024PMC
September 2021

Next-generation prebiotic promotes selective growth of bifidobacteria, suppressing .

Gut Microbes 2021 Jan-Dec;13(1):1973835

Research Institute for Bioresources and Biotechnology, Ishikawa Prefectural University, Nonoichi, Ishikawa, Japan.

Certain existing prebiotics meant to facilitate the growth of beneficial bacteria in the intestine also promote the growth of other prominent bacteria. Therefore, the growth-promoting effects of β-galactosides on intestinal bacteria were analyzed. Galactosyl-β1,4-l-rhamnose (Gal-β1,4-Rha) selectively promoted the growth of subsp. 105-A (JCM 31944) has multiple solute-binding proteins belonging to ATP-binding cassette transporters for sugars. Each strain in the library of 11 subsp. mutants, in which each gene of the solute-binding protein was disrupted, was cultured in a medium containing Gal-β1,4-Rha as the sole carbon source, and only the BL105A_0502 gene-disruption mutant showed delayed and reduced growth compared to the wild-type strain. BL105A_0502 homolog is highly conserved in bifidobacteria. In a Gal-β1,4-Rha-containing medium, subsp. JCM 1222, which possesses BLIJ_2090, a homologous protein to BL105A_0502, suppressed the growth of enteric pathogen , whereas the BLIJ_2090 gene-disrupted mutant did not. , administration of and Gal-β1,4-Rha alleviated infection-related weight loss in mice. We have successfully screened Gal-β1,4-Rha as a next-generation prebiotic candidate that specifically promotes the growth of beneficial bacteria without promoting the growth of prominent bacteria and pathogens.
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http://dx.doi.org/10.1080/19490976.2021.1973835DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8475593PMC
January 2022

Evolution of milk oligosaccharides: Origin and selectivity of the ratio of milk oligosaccharides to lactose among mammals.

Biochim Biophys Acta Gen Subj 2022 01 16;1866(1):130012. Epub 2021 Sep 16.

School of Molecular Bioscience, The University of Sydney, Sydney, NSW 2006, Australia.

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 β4galactosyltransferase 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 (β-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.
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http://dx.doi.org/10.1016/j.bbagen.2021.130012DOI Listing
January 2022

Ecological and molecular perspectives on responders and non-responders to probiotics and prebiotics.

Curr Opin Biotechnol 2021 Aug 7;73:108-120. Epub 2021 Aug 7.

Graduate School of Biostudies, Kyoto University, Kyoto, 606-8502, Japan. Electronic address:

Bifidobacteria are widely used as a probiotic for their health-promoting effects. To promote their growth, bifidogenic prebiotics, including human milk oligosaccharides (HMOs), have been added to supplements and infant formula. However, the efficacy of both probiotic and prebiotic interventions is often debated, as clinical responses vary significantly by case. Here, we review clinical studies that aimed to proliferate human-residential Bifidobacterium (HRB) strains in the gut, and we highlight the difference between responders and non-responders to such interventions through an ecological, niche-based perspective and an examination of the prevalence of genes responsible for prebiotic assimilation in HRB genomes. We discuss the criteria necessary to better evaluate the efficacy of probiotic and prebiotic interventions and the recent therapeutic potential shown by synbiotics.
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http://dx.doi.org/10.1016/j.copbio.2021.06.023DOI Listing
August 2021

Selection of the optimal tyrosine hydroxylation enzyme for (S)-reticuline production in Escherichia coli.

Appl Microbiol Biotechnol 2021 Jul 28;105(13):5433-5447. Epub 2021 Jun 28.

Research Institute for Bioresources and Biotechnology, Ishikawa Prefectural University, 1-308 Suematsu, Nonoichi-shi, Ishikawa, Japan.

We have constructed an Escherichia coli-based platform producing (S)-reticuline, an important intermediate of benzylisoquinoline alkaloids (BIAs), using up to 14 genes. (S)-reticuline was produced from a simple carbon source such as glucose and glycerol via L-DOPA, which is synthesized by hydroxylation of L-tyrosine, one of the rate-limiting steps of the reaction. There are three kinds of enzymes catalyzing tyrosine hydroxylation: tyrosinase (TYR), tyrosine hydroxylase (TH), and 4-hydroxyphenylacetate 3-monooxygenase (HpaBC). Here, to further improve (S)-reticuline production, we chose eight from these three kinds of tyrosine hydroxylation enzymes (two TYRs, four THs, and two HpaBCs) derived from various organisms, and examined which enzyme was optimal for (S)-reticuline production in E. coli. TH from Drosophila melanogaster was the most suitable for (S)-reticuline production under the experimental conditions tested. We improved the productivity by genome integration of a gene set for L-tyrosine overproduction, introducing the regeneration pathway of BH, a cofactor of TH, and methionine addition to enhance the S-adenosylmethionine supply. As a result, the yield of (S)-reticuline reached up to 384 μM from glucose in laboratory-scale shake flask. Furthermore, we found three inconsistent phenomena: an inhibitory effect due to additional gene expression, conflicts among the experimental conditions, and interference of an upstream enzyme from an additional downstream enzyme. Based on these results, we discuss future perspectives and challenges of integrating multiple enzyme genes for material production using microbes. Graphical abstract The optimal tyrosine hydroxylation enzyme for (S)-reticuline production in Escherichia coli KEY POINTS: • There are three types of enzymes catalyzing tyrosine hydroxylation reaction: tyrosinase, tyrosine hydroxylase, and 4-hydroxyphenylacetate 3-monooxygenase. • Tyrosine hydroxylase from Drosophila melanogaster exhibited the highest activity and was suitable for (S)-reticuline production in E. coli. • New insights were provided on constructing an alkaloid production system with multi-step reactions in E. coli.
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http://dx.doi.org/10.1007/s00253-021-11401-zDOI Listing
July 2021

Bifidobacterium response to lactulose ingestion in the gut relies on a solute-binding protein-dependent ABC transporter.

Commun Biol 2021 05 10;4(1):541. Epub 2021 May 10.

Next Generation Science Institute, RD Division, Morinaga Milk Industry Co., Ltd., Zama, Japan.

This study aims to understand the mechanistic basis underlying the response of Bifidobacterium to lactulose ingestion in guts of healthy Japanese subjects, with specific focus on a lactulose transporter. An in vitro assay using mutant strains of Bifidobacterium longum subsp. longum 105-A shows that a solute-binding protein with locus tag number BL105A_0502 (termed LT-SBP) is primarily involved in lactulose uptake. By quantifying faecal abundance of LT-SBP orthologues, which is defined by phylogenetic analysis, we find that subjects with 10 to 10 copies of the genes per gram of faeces before lactulose ingestion show a marked increase in Bifidobacterium after ingestion, suggesting the presence of thresholds between responders and non-responders to lactulose. These results help predict the prebiotics-responder and non-responder status and provide an insight into clinical interventions that test the efficacy of prebiotics.
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http://dx.doi.org/10.1038/s42003-021-02072-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8110962PMC
May 2021

Isolation and identification of milk oligosaccharide-degrading bacteria from the intestinal contents of suckling rats.

Biosci Microbiota Food Health 2021 8;40(1):27-32. Epub 2020 Aug 8.

Graduate School of Agricultural Science, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe, Hyogo 657-8501, Japan.

We report the isolation of bacteria capable of degrading milk oligosaccharides from suckling infant rats. The bacteria were successfully isolated via a selective enrichment method, in which the serially diluted intestinal contents of infant rats were individually incubated in an enrichment medium containing 3'-sialyllactose (3'-SL), followed by the isolation of candidate strains from streaked agar plates and selection of 3'-SL-degrading strains using thin-layer chromatography. Subsequent genomic and phenotypic analyses identified all strains as . The strains were capable of degrading both 3'-SL and 6'-SL, which was not observed with the type strain of used as a reference. Furthermore, a time-course study combining high-performance anion-exchange chromatography with pulsed amperometric detection revealed that the representative strain AH4 degraded 3'-SL completely to yield an equimolar amount of lactose and an approximately one-fourth equimolar amount of sialic acid after 24 hr of anaerobic incubation. These findings point to a possibility that the enterococci degrade rat milk oligosaccharides to "cross-feed" their degradants to other members of concomitant bacteria in the gut of the infant rat.
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http://dx.doi.org/10.12938/bmfh.2020-024DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7817515PMC
August 2020

Suppresses Gut Inflammation Caused by Repeated Antibiotic Disturbance Without Recovering Gut Microbiome Diversity in Mice.

Front Microbiol 2020 18;11:1349. Epub 2020 Jun 18.

Division of Integrated Life Science, Graduate School of Biostudies, Kyoto University, Kyoto, Japan.

The gut microbiome is a dynamic community that significantly affects host health; it is frequently disturbed by medications such as antibiotics. Recently, probiotics have been proposed as a remedy for antibiotic-induced dysbiosis, but the efficacy of such treatments remains uncertain. Thus, the effect of specific antibiotic-probiotic combinations on the gut microbiome and host health warrants further research. We tested the effect vancomycin, amoxicillin, and ciprofloxacin on mice. Antibiotic administration was followed by one of the following recovery treatments: JCM 1254 as a probiotic (PR); fecal transplant (FT); or natural recovery (NR). Each antibiotic administration and recovery treatment was repeated three times over 9 weeks. We used the Shannon Index and Chao1 Index to determine gut microbiome diversity and assessed recovery by quantifying the magnitude of microbial shift using the Bray-Curtis Index of Dissimilarity. We determined the community composition by sequencing the V3-V4 regions of the 16S ribosomal RNA gene. To assess host health, we measured body weight and cecum weight, as well as mRNA expression of inflammation-related genes by reverse-transcription quantitative PCR. Our results show that community response varied by the type of antibiotic used, with vancomycin having the most significant effects. As a result, the effect of probiotics and fecal transplants also varied by antibiotic type. For vancomycin, the first antibiotic disturbance substantially increased the relative abundance of inflammatory species in the phylum Proteobacteria, such as , but the effect of subsequent disturbances was less pronounced, suggesting that the gut microbiome is affected by past disturbance events. Furthermore, although gut microbiome diversity did not recover, probiotic supplementation was effective in limiting cecum size enlargement and colonic inflammation caused by vancomycin. However, for amoxicillin and ciprofloxacin, the relative abundances of proinflammatory species were not greatly affected, and consequently, the effect of probiotic supplementation on community structure, cecum weight, and expression of inflammation-related genes was comparatively negligible. These results indicate that probiotic supplementation is effective, but only when antibiotics cause proinflammatory species-induced gut inflammation, suggesting that the necessity of probiotic supplementation is strongly influenced by the type of disturbance introduced to the community.
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http://dx.doi.org/10.3389/fmicb.2020.01349DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7314955PMC
June 2020

Butyrate producing colonic Clostridiales metabolise human milk oligosaccharides and cross feed on mucin via conserved pathways.

Nat Commun 2020 07 3;11(1):3285. Epub 2020 Jul 3.

Department of Biotechnology and Biomedicine, Technical University of Denmark, 2800, Lyngby, Denmark.

The early life human gut microbiota exerts life-long health effects on the host, but the mechanisms underpinning its assembly remain elusive. Particularly, the early colonization of Clostridiales from the Roseburia-Eubacterium group, associated with protection from colorectal cancer, immune- and metabolic disorders is enigmatic. Here, we describe catabolic pathways that support the growth of Roseburia and Eubacterium members on distinct human milk oligosaccharides (HMOs). The HMO pathways, which include enzymes with a previously unknown structural fold and specificity, were upregulated together with additional glycan-utilization loci during growth on selected HMOs and in co-cultures with Akkermansia muciniphila on mucin, suggesting an additional role in enabling cross-feeding and access to mucin O-glycans. Analyses of 4599 Roseburia genomes underscored the preponderance and diversity of the HMO utilization loci within the genus. The catabolism of HMOs by butyrate-producing Clostridiales may contribute to the competitiveness of this group during the weaning-triggered maturation of the microbiota.
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http://dx.doi.org/10.1038/s41467-020-17075-xDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7335108PMC
July 2020

Sialylated -Glycans from Hen Egg White Ovomucin are Decomposed by Mucin-degrading Gut Microbes.

J Appl Glycosci (1999) 2020 20;67(2):31-39. Epub 2020 May 20.

1 Graduate School of Biostudies, Kyoto University.

Ovomucin, a hen egg white protein, is characterized by its hydrogel-forming properties, high molecular weight, and extensive -glycosylation with a high degree of sialylation. As a commonly used food ingredient, we explored whether ovomucin has an effect on the gut microbiota. Glycan analysis revealed that ovomucin contained core-1 and 2 structures with heavy modification by -acetylneuraminic acid and/or sulfate groups. Of the two mucin-degrading gut microbes we tested, grew in medium containing ovomucin as a sole carbon source during a 24 h culture period, whereas did not. Both gut microbes, however, degraded ovomucin -glycans and released monosaccharides into the culture supernatants in a species-dependent manner, as revealed by semi-quantified mass spectrometric analysis and anion exchange chromatography analysis. Our data suggest that ovomucin potentially affects the gut microbiota through -glycan decomposition by gut microbes and degradant sugar sharing within the community.
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http://dx.doi.org/10.5458/jag.jag.JAG-2019_0020DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8279891PMC
May 2020

Enzymatic Adaptation of to Host Glycans, Viewed from Glycoside Hydrolyases and Carbohydrate-Binding Modules.

Microorganisms 2020 Mar 28;8(4). Epub 2020 Mar 28.

Graduate School of Biostudies, Kyoto University, Sakyo-ku, Kyoto 606-8502, Japan.

Certain species of the genus represent human symbionts. Many studies have shown that the establishment of symbiosis with such bifidobacterial species confers various beneficial effects on human health. Among the more than ten (sub)species of human gut-associated that have significantly varied genetic characteristics at the species level, is unique in that it is found in the intestines of a wide age group, ranging from infants to adults. This species is likely to have adapted to efficiently degrade host-derived carbohydrate chains, such as human milk oligosaccharides (HMOs) and mucin -glycans, which enabled the longitudinal colonization of intestines. The ability of this species to assimilate various host glycans can be attributed to the possession of an adequate set of extracellular glycoside hydrolases (GHs). Importantly, the polypeptides of those glycosidases frequently contain carbohydrate-binding modules (CBMs) with deduced affinities to the target glycans, which is also a distinct characteristic of this species among members of human gut-associated bifidobacteria. This review firstly describes the prevalence and distribution of in the human gut and then explains the enzymatic machinery that has developed for host glycan degradation by referring to the functions of GHs and CBMs. Finally, we show the data of co-culture experiments using host-derived glycans as carbon sources, which underpin the interesting altruistic behavior of this species as a cross-feeder.
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http://dx.doi.org/10.3390/microorganisms8040481DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7232152PMC
March 2020

1,6-α-L-Fucosidases from subsp. ATCC 15697 Involved in the Degradation of Core-fucosylated -Glycan.

J Appl Glycosci (1999) 2020 20;67(1):23-29. Epub 2020 Feb 20.

3 Faculty of Agriculture, Kyushu University.

subsp. ATCC 15697 possesses five α-L-fucosidases, which have been previously characterized toward fucosylated human milk oligosaccharides containing α1,2/3/4-linked fucose [Sela : 78, 795-803 (2012)]. In this study, two glycoside hydrolase family 29 α-L-fucosidases out of five (Blon_0426 and Blon_0248) were found to be 1,6-α-L-fucosidases acting on core α1,6-fucose on the -glycan of glycoproteins. These enzymes readily hydrolyzed p-nitrophenyl-α-L-fucoside and Fucα1-6GlcNAc, but hardly hydrolyzed Fucα1-6(GlcNAcβ1-4)GlcNAc, suggesting that they de-fucosylate Fucα1-6GlcNAcβ1-Asn-peptides/proteins generated by the action of endo-β- -acetylglucosaminidase. We demonstrated that Blon_0426 can de-fucosylate Fucα1-6GlcNAc-IgG prepared from Rituximab using Endo-CoM from . To generate homogenous non-fucosylated -glycan-containing IgG with high antibody-dependent cellular cytotoxicity (ADCC) activity, the resulting GlcNAc-IgG has a potential to be a good acceptor substrate for the glycosynthase mutant of Endo-M from . Collectively, our results strongly suggest that Blon_0426 and Blon_0248 are useful for glycoprotein glycan remodeling.
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http://dx.doi.org/10.5458/jag.jag.JAG-2019_0016DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8367633PMC
February 2020

Varied Pathways of Infant Gut-Associated to Assimilate Human Milk Oligosaccharides: Prevalence of the Gene Set and Its Correlation with Bifidobacteria-Rich Microbiota Formation.

Nutrients 2019 Dec 26;12(1). Epub 2019 Dec 26.

Graduate School of Biostudies, Kyoto University, Kyoto 606-8502, Japan.

The infant's gut microbiome is generally rich in the genus. The mother's milk contains natural prebiotics, called human milk oligosaccharides (HMOs), as the third most abundant solid component after lactose and lipids, and of the different gut microbes, infant gut-associated bifidobacteria are the most efficient in assimilating HMOs. Indeed, the fecal concentration of HMOs was found to be negatively correlated with the fecal abundance of in infants. Given these results, two HMO molecules, 2'-fucosyllactose and lacto--tetraose, have recently been industrialized to fortify formula milk. As of now, however, our knowledge about the HMO consumption pathways in infant gut-associated bifidobacteria is still incomplete. The recent studies indicate that HMO assimilation abilities significantly vary among different species and strains. Therefore, to truly maximize the effects of prebiotic and probiotic supplementation in commercialized formula, we need to understand HMO consumption behaviors of bifidobacteria in more detail. In this review, we summarized how different species/strains are equipped with varied gene sets required for HMO assimilation. We then examined the correlation between the abundance of the HMO-related genes and bifidobacteria-rich microbiota formation in the infant gut through data mining analysis of a deposited fecal microbiome shotgun sequencing dataset. Finally, we shortly described future perspectives on HMO-related studies.
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http://dx.doi.org/10.3390/nu12010071DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7019425PMC
December 2019

Mitotic cyclin Clb4 is required for the intracellular adaptation to glucose starvation in Saccharomyces cerevisiae.

FEBS Lett 2020 04 29;594(8):1329-1338. Epub 2019 Dec 29.

Graduate School of Bioresources, Mie University, Tsu, Japan.

Cellular homeostasis in response to glucose availability is maintained through the tight coordination of various physiological processes, including cell proliferation, transcription, and metabolism. In this study, we use the budding yeast Saccharomyces cerevisiae to identify proteins implicated in carbon source-dependent modulation of physiological processes. We find that the mitotic cyclin Clb4 is required for optimal regulation of glucose-starvation-responsive pathways through the target of rapamycin complex 1. Cells lacking Clb4 are characterized by dysregulation of autophagy and impaired modulation of cell size. Notably, cell viability after prolonged glucose starvation is severely reduced by disruption of Clb4. We conclude that Clb4, in addition to its function in the cell cycle, plays a role in the intracellular adaptation to glucose starvation.
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http://dx.doi.org/10.1002/1873-3468.13722DOI Listing
April 2020

Evolutionary adaptation in fucosyllactose uptake systems supports bifidobacteria-infant symbiosis.

Sci Adv 2019 08 28;5(8):eaaw7696. Epub 2019 Aug 28.

Faculty of Bioresources and Environmental Sciences, Ishikawa Prefectural University, Nonoichi, Ishikawa 921-8836, Japan.

The human gut microbiota established during infancy has persistent effects on health. In vitro studies have suggested that human milk oligosaccharides (HMOs) in breast milk promote the formation of a bifidobacteria-rich microbiota in infant guts; however, the underlying molecular mechanism remains elusive. Here, we characterized two functionally distinct but overlapping fucosyllactose transporters (FL transporter-1 and -2) from subspecies . Fecal DNA and HMO consumption analyses, combined with deposited metagenome data mining, revealed that FL transporter-2 is primarily associated with the bifidobacteria-rich microbiota formation in breast-fed infant guts. Structural analyses of the solute-binding protein (SBP) of FL transporter-2 complexed with 2'-fucosyllactose and 3-fucosyllactose, together with phylogenetic analysis of SBP homologs of both FL transporters, highlight a unique adaptation strategy of to HMOs, in which the gain-of-function mutations enable FL transporter-2 to efficiently capture major fucosylated HMOs. Our results provide a molecular insight into HMO-mediated symbiosis and coevolution between bifidobacteria and humans.
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http://dx.doi.org/10.1126/sciadv.aaw7696DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6713505PMC
August 2019

Neonatal oral fluid as a transmission route for bifidobacteria to the infant gut immediately after birth.

Sci Rep 2019 06 18;9(1):8692. Epub 2019 Jun 18.

Next Generation Science Institute R&D Division, Morinaga Milk Industry Co., Ltd., Kanagawa, 252-8583, Japan.

Bifidobacteria are one of the most abundant bacterial groups in the infant gut microbiota and are closely associated with infant health and can potentially affect health in later life. However, the details regarding the source of bifidobacteria have yet to be completely elucidated. This study aimed to assess neonatal oral fluid (OF) as a transmission route for bifidobacteria to the infant gut during delivery. Neonatal OF and infant feces (IF) were collected immediately and one month after birth from 15 healthy vaginally delivered newborns. Bifidobacterium strains were isolated from OF and IF samples, and the similarity of strains between the OF-IF pairs was evaluated based on the average nucleotide identity (ANI) value. The 16S rRNA gene sequencing results revealed the presence of Bifidobacteriaceae at >1% relative abundance in all OF samples. Bifidobacterium strains were isolated from OF (9/15) and IF (11/15) samples, and those sharing high genomic homology (ANI values >99.5%) between the neonatal OF and IF samples were present in one-third of the OF-IF pairs. The results of this study indicate that viable bifidobacteria are present in neonatal OF and that OF at birth is a possible transmission route of bifidobacteria to the infant gut.
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http://dx.doi.org/10.1038/s41598-019-45198-9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6582144PMC
June 2019

Preclinical Development of a WT1 Oral Cancer Vaccine Using a Bacterial Vector to Treat Castration-Resistant Prostate Cancer.

Mol Cancer Ther 2019 05 1;18(5):980-990. Epub 2019 Mar 1.

Division of Advanced Medical Science, Kobe University Graduate School of Science, Technology and Innovation, Kobe, Japan.

Previously, we constructed a recombinant displaying a partial mouse Wilms' tumor 1 (WT1) protein ( 420) as an oral cancer vaccine using a bacterial vector and demonstrated that oral administration of 420 significantly inhibited tumor growth compared with the Db126 WT1 peptide vaccine in the TRAMP-C2, mouse castration-resistant prostate cancer (CRPC) syngeneic tumor model. The present study demonstrated that oral administration of 1.0×10 colony-forming units of 420 induced significantly higher cytotoxicity against TRAMP-C2 cells than intraperitoneal injection of 100 μg of Db126, and the antitumor activity of 420 in the TRAMP-C2 tumor model could be augmented by intraperitoneal injections of 250 μg of anti-PD-1 antibody. For the clinical development, we produced the B440 pharmaceutical formulation, which is lyophilized powder of inactivated 440 displaying the partially modified human WT1 protein. We confirmed that 440 could induce cellular immunity specific to multiple WT1 epitopes. In a preclinical dosage study, B440 significantly inhibited growth of the TRAMP-C2 tumors compared with that of the control groups (PBS and not expressing WT1) at all dosages (1, 5, and 10 mg/body of B440). These mouse doses were considered to correspond with practical oral administration doses of 0.2, 1, and 2 g/body for humans. Taken together, these results suggest that the B440 WT1 oral cancer vaccine can be developed as a novel oral immuno-oncology drug to treat CRPC as a monotherapy or as an adjunct to immune checkpoint inhibitors.
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http://dx.doi.org/10.1158/1535-7163.MCT-18-1105DOI Listing
May 2019

Minority species influences microbiota formation: the role of Bifidobacterium with extracellular glycosidases in bifidus flora formation in breastfed infant guts.

Microb Biotechnol 2019 03 13;12(2):259-264. Epub 2019 Jan 13.

Graduate School of Biostudies, Kyoto University, Sakyo-ku, Kyoto, 606-8502, Japan.

The human body houses a variety of microbial ecosystems, such as the microbiotas on the skin, in the oral cavity and in the digestive tract. The gut microbiota is one such ecosystem that contains trillions of bacteria, and it is well established that it can significantly influence host health and diseases. With the advancement in bioinformatics tools, numerous comparative studies based on 16S ribosomal RNA (rRNA) gene sequences, metabolomics, pathological and epidemical analyses have revealed the correlative relationship between the abundance of certain taxa and disease states or amount of certain causative bioactive compounds. However, the 16S rRNA-based taxonomic analyses using next-generation sequencing (NGS) technology essentially detect only the majority species. Although the entire gut microbiome consists of 10 microbial cells, NGS read counts are given in multiples of 10 , making it difficult to determine the diversity of the entire microbiota. Some recent studies have reported instances where certain minority species play a critical role in creating locally stable conditions for other species by stabilizing the fundamental microbiota, despite their low abundance. These minority species act as 'keystone species', which is a species whose effect on the community is disproportionately large compared to its relative abundance. One of the attributes of keystone species within the gut microbiota is its extensive enzymatic capacity for substrates that are rare or difficult to degrade for other species, such as dietary fibres or host-derived complex glycans, like human milk oligosaccharides (HMOs). In this paper, we propose that more emphasis should be placed on minority taxa and their possible role as keystone species in gut microbiota studies by referring to our recent studies on HMO-mediated microbiota formation in the infant gut.
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http://dx.doi.org/10.1111/1751-7915.13366DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6389856PMC
March 2019

Sharing of human milk oligosaccharides degradants within bifidobacterial communities in faecal cultures supplemented with Bifidobacterium bifidum.

Sci Rep 2018 09 18;8(1):13958. Epub 2018 Sep 18.

Graduate School of Biostudies, Kyoto University, Sakyo-ku, Kyoto, 606-8502, Japan.

Gut microbiota of breast-fed infants are generally rich in bifidobacteria. Recent studies show that infant gut-associated bifidobacteria can assimilate human milk oligosaccharides (HMOs) specifically among the gut microbes. Nonetheless, little is known about how bifidobacterial-rich communities are shaped in the gut. Interestingly, HMOs assimilation ability is not related to the dominance of each species. Bifidobacterium longum susbp. longum and Bifidobacterium breve are commonly found as the dominant species in infant stools; however, they show limited HMOs assimilation ability in vitro. In contrast, avid in vitro HMOs consumers, Bifidobacterium bifidum and Bifidobacterium longum subsp. infantis, are less abundant in infant stools. In this study, we observed altruistic behaviour by B. bifidum when incubated in HMOs-containing faecal cultures. Four B. bifidum strains, all of which contained complete sets of HMO-degrading genes, commonly left HMOs degradants unconsumed during in vitro growth. These strains stimulated the growth of other Bifidobacterium species when added to faecal cultures supplemented with HMOs, thereby increasing the prevalence of bifidobacteria in faecal communities. Enhanced HMOs consumption by B. bifidum-supplemented cultures was also observed. We also determined the complete genome sequences of B. bifidum strains JCM7004 and TMC3115. Our results suggest B. bifidum-mediated cross-feeding of HMOs degradants within bifidobacterial communities.
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http://dx.doi.org/10.1038/s41598-018-32080-3DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6143587PMC
September 2018

Bifunctional properties and characterization of a novel sialidase with esterase activity from Bifidobacterium bifidum.

Biosci Biotechnol Biochem 2018 Nov 20;82(11):2030-2039. Epub 2018 Jul 20.

a Department of Applied Molecular Biology, Division of Integrated Life Science , Graduate School of Biostudies, Kyoto University , Kyoto , Japan.

Sialidases catalyze the removal of terminal sialic acid from various complex carbohydrates. In the gastrointestinal tract, sialic acid is commonly found in the sugar chain of mucin, and many enteric commensals use mucin as a nutrient source. We previously identified two different sialidase genes in Bifidobacterium bifidum, and one was cloned and expressed as an extracellular protein designated as exo-α-sialidase SiaBb2. The other exo-α-sialidase gene (siabb1) from the same bifidobacterium encodes an extracellular protein (SiaBb1) consisting of 1795 amino acids with a molecular mass of 189 kDa. SiaBb1 possesses a catalytic domain that classifies this enzyme as a glycoside hydrolase family 33 member. SiaBb1 preferentially hydrolyzes α2,3-linked sialic acid over α2,6-linked sialic acid from sialoglycan, which is the same as SiaBb2. However, SiaBb1 has an SGNH hydrolase domain with sialate-O-acetylesterase activity and an N-terminal signal sequence and C-terminal transmembrane region. SiaBb1 is the first bifunctional sialidase identified with esterase activity. Abbreviations: GalNAc: N-acetyl-D-galactosamine; Fuc: L-fucose; Gal: D-galactose.
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http://dx.doi.org/10.1080/09168451.2018.1497944DOI Listing
November 2018

Microbial production of novel sulphated alkaloids for drug discovery.

Sci Rep 2018 05 22;8(1):7980. Epub 2018 May 22.

Research Institute for Bioresources and Biotechnology, Ishikawa Prefectural University, 1-308 Suematsu, Nonoichi, Ishikawa, 921-8836, Japan.

Natural products from plants are useful as lead compounds in drug discovery. Plant benzylisoquinoline alkaloids (BIAs) exhibit various pharmaceutical activities. Although unidentified BIAs are expected to be of medicinal value, sufficient quantities of such BIAs, for biological assays, are sometimes difficult to obtain due to their low content in natural sources. Here, we showed that high productivity of BIAs in engineered Escherichia coli could be exploited for drug discovery. First, we improved upon the previous microbial production system producing (S)-reticuline, an important BIA intermediate, to obtain yields of around 160 mg/L, which was 4-fold higher than those of the previously reported highest production system. Subsequently, we synthesised non-natural BIAs (O-sulphated (S)-reticulines) by introducing human sulphotransferases into the improved (S)-reticuline production system. Analysis of human primary cells treated with these BIAs demonstrated that they affected a biomarker expression in a manner different from that by the parent compound (S)-reticuline, suggesting that simple side-chain modification altered the characteristic traits of BIA. These results indicated that highly productive microbial systems might facilitate the production of scarce or novel BIAs and enable subsequent evaluation of their biological activities. The system developed here could be applied to other rare natural products and might contribute to the drug-discovery process as a next-generation strategy.
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http://dx.doi.org/10.1038/s41598-018-26306-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5964154PMC
May 2018

Discovery of α-l-arabinopyranosidases from human gut microbiome expands the diversity within glycoside hydrolase family 42.

J Biol Chem 2017 12 23;292(51):21092-21101. Epub 2017 Oct 23.

From the Department of Biotechnology, The University of Tokyo, Tokyo 113-8657, Japan,

Enzymes of the glycoside hydrolase family 42 (GH42) are widespread in bacteria of the human gut microbiome and play fundamental roles in the decomposition of both milk and plant oligosaccharides. All GH42 enzymes characterized so far have β-galactosidase activity. Here, we report the existence of a GH42 subfamily that is exclusively specific for α-l-arabinopyranoside and describe the first representative of this subfamily. We found that this enzyme (Arap42B) from a probiotic species cannot hydrolyze β-galactosides. However, Arap42B effectively hydrolyzed paeonolide and ginsenoside Rb2, plant glycosides containing an aromatic aglycone conjugated to α-l-arabinopyranosyl-(1,6)-β-d-glucopyranoside. Paeonolide, a natural glycoside from the roots of the plant genus is not hydrolyzed by classical GH42 β-galactosidases. X-ray crystallography revealed a unique Trp--Trp sequence motif at the Arap42B active site, as compared with a Phe--His motif in classical GH42 β-galactosidases. This analysis also indicated that the C6 position of galactose is blocked by the aromatic side chains, hence allowing accommodation only of Ara lacking this carbon. Automated docking of paeonolide revealed that it can fit into the Ara42B active site. The Glc moiety of paeonolide stacks onto the aromatic ring of the Trp at subsite +1 and C4-OH is hydrogen bonded with Asp Moreover, the aglycone stacks against Phe from the neighboring monomer in the Ara42B trimer, forming a proposed subsite +2. These results further support the notion that evolution of metabolic specialization can be tracked at the structural level in key enzymes facilitating degradation of specific glycans in an ecological niche.
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http://dx.doi.org/10.1074/jbc.M117.792598DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5743082PMC
December 2017

Recombinant expression, purification, and characterization of polyphenol oxidase 2 (VvPPO2) from "Shine Muscat" (Vitis labruscana Bailey × Vitis vinifera L.).

Biosci Biotechnol Biochem 2017 Dec 11;81(12):2330-2338. Epub 2017 Oct 11.

d Faculty of Life and Environmental Science , Shimane University , Matsue , Japan.

Polyphenol oxidases (PPOs) catalyze browning reactions in various plant organs, therefore controlling the reactions is important for the food industry. PPOs have been assumed to be involved in skin browning of white grape cultivars; however, the molecular mechanism underlying PPO-mediated browning process remains elusive. We have recently identified a new PPO gene named VvPPO2 from "Shine Muscat" (Vitis labruscana Bailey × V. vinifera L.), and have shown that the gene is transcribed at a higher level than the previously identified VvPPO1 in browning, physiologically disordered berry skins at the maturation stage. In this study, we expressed VvPPO2 in Escherichia coli and, using the purified preparation, revealed unique physicochemical characteristics of the enzyme. Our study opens up a way to not only understand the berry skin browning process but also to elucidate the enzymatic maturation process of grape PPOs.
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http://dx.doi.org/10.1080/09168451.2017.1381017DOI Listing
December 2017

Identification and characterization of a sulfoglycosidase from Bifidobacterium bifidum implicated in mucin glycan utilization.

Biosci Biotechnol Biochem 2017 Oct 17;81(10):2018-2027. Epub 2017 Aug 17.

a Graduate School of Biostudies , Kyoto University , Kyoto , Japan.

Human gut symbiont bifidobacteria possess carbohydrate-degrading enzymes that act on the O-linked glycans of intestinal mucins to utilize those carbohydrates as carbon sources. However, our knowledge about mucin type O-glycan degradation by bifidobacteria remains fragmentary, especially regarding how they decompose sulfated glycans, which are abundantly found in mucin sugar-chains. Here, we examined the abilities of several Bifidobacterium strains to degrade a sulfated glycan substrate and identified a 6-sulfo-β-d-N-acetylglucosaminidase, also termed sulfoglycosidase, encoded by bbhII from Bifidobacterium bifidum JCM 7004. A recombinant BbhII protein showed a substrate preference toward 6-sulfated and 3,4-disulfated N-acetylglucosamines over non-sulfated and 3-sulfated N-acetylglucosamines. The purified BbhII directly released 6-sulfated N-acetylglucosamine from porcine gastric mucin and the expression of bbhII was moderately induced in the presence of mucin. This de-capping activity may promote utilization of sulfated glycans of mucin by other bacteria including bifidobacteria, thereby establishing the symbiotic relationship between human and gut microbes.
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http://dx.doi.org/10.1080/09168451.2017.1361810DOI Listing
October 2017

Use of Gifu Anaerobic Medium for culturing 32 dominant species of human gut microbes and its evaluation based on short-chain fatty acids fermentation profiles.

Biosci Biotechnol Biochem 2017 Oct 7;81(10):2009-2017. Epub 2017 Aug 7.

a Research Institute for Bioresources and Biotechnology , Ishikawa Prefectural University , Nonoichi , Japan.

Recently, a "human gut microbial gene catalogue," which ranks the dominance of microbe genus/species in human fecal samples, was published. Most of the bacteria ranked in the catalog are currently publicly available; however, the growth media recommended by the distributors vary among species, hampering physiological comparisons among the bacteria. To address this problem, we evaluated Gifu anaerobic medium (GAM) as a standard medium. Forty-four publicly available species of the top 56 species listed in the "human gut microbial gene catalogue" were cultured in GAM, and out of these, 32 (72%) were successfully cultured. Short-chain fatty acids from the bacterial culture supernatants were then quantified, and bacterial metabolic pathways were predicted based on in silico genomic sequence analysis. Our system provides a useful platform for assessing growth properties and analyzing metabolites of dominant human gut bacteria grown in GAM and supplemented with compounds of interest.
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http://dx.doi.org/10.1080/09168451.2017.1359486DOI Listing
October 2017
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