Effects of difructose anhydride III (DFA III) administration on rat intestinal microbiota

Degradation mechanism of difructose dianhydride III in Blautia species

Di-fructofuranose 1,2':2,3' dianhydride (DFA-III) is a cyclic fructo-disaccharide, which is produced by the condensation of two fructose molecules via the caramelization or enzymatic reaction of inulin fructotransferase. A strain of Blautia producta was known to utilize DFA-III as a carbohydrate source; however, the mechanisms remain unclear. In this study, we characterized the glycoside hydrolase (GH) family 91 DFA-III hydrolase (DFA-IIIase) from B. parvula NBRC 113351. Recombinant BpDFA-IIIase catalyzed the reversible conversion of DFA-III to inulobiose, which is further degraded to fructose by the cooperative action of DFA-IIIase and GH32 β-D-fructofuranosidase. DFA-III was utilized in several Blautia species with a gene cluster for DFA-III degradation (e.g., B. parvula NBRC 113351, B. hydrogenotrophica JCM 14656, and B. wexlerae JCM 35486), but not by B. wexlerae JCM 31267, which does not possess the gene cluster. Furthermore, B. hansenii JCM 14655, which cannot metabolize fructose, could not utilize DFA-III; however, it could degrade DFA-III to fructose in the presence of DFA-III-degrading enzymes. Fecal fermentation tests showed that Blautia species are important gut microbe for degrading DFA-III. KEY POINTS: • BpDFA-IIIase is the first characterized DFA-IIIase in intestinal non-pathogenic bacteria. • DFA-IIIase is widely conserved in Blautia species. • DFA-III is degraded to d-fructose through inulobiose by the cooperative action of DFA-IIIase and β-d-fructofuranosidase.

Difructose anhydride III: a 50-year perspective on its production and physiological functions

Production and applications of difructose anhydride III (DFA-III) have attracted considerable attention because of its versatile physiological functions. Recently, large-scale production of DFA-III has been continuously explored, which opens a horizon for applications in the food and pharmaceutical industries. This review updates recent advances involving DFA-III, including: biosynthetic strategies, purification, and large-scale production of DFA-III; physiological functions of DFA-III and related mechanisms; DFA-III safety evaluations; present applications in food systems, existing problems, and further research prospects. Currently, enzymatic synthesis of DFA-III has been conducted both industrially and in academic research. Two biosynthetic strategies for DFA-III production are summarized: single- and double enzyme-mediated. DFA-III purification is achieved via yeast fermentation. Enzyme membrane bioreactors have been applied to meet the large-scale production demands for DFA-III. In addition, the primary physiological functions of DFA-III and their underlying mechanisms have been proposed. However, current applications of DFA-III are limited. Further research regarding DFA-III should focus on commercial production and purification, comprehensive study of physiological properties, extensive investigation of large-scale human experiments, and expansion of industrial applications. It is worthy to dig deep into potential application and commercial value of DFA-III.

Fructo-Oligosaccharide (DFA III) Feed Supplementation for Mitigation of Mycotoxin Exposure in Cattle-Clinical Evaluation by a Urinary Zearalenone Monitoring System

The potential effect of difructose anhydride III (DFA III) supplementation in cattle feed was evaluated using a previously developed urinary-zearalenone (ZEN) monitoring system. Japanese Black cattle from two beef herds aged 9⁻10 months were used. DFA III was supplemented for two weeks. ZEN concentrations in feed were similar in both herds (0.27 and 0.22 mg/kg in roughage and concentrates, respectively), and below the maximum allowance in Japan. ZEN, α-zearalenol (α-ZOL), and β-ZOL concentrations in urine were measured using LC/MS/MS the day before DFA III administration, 9 and 14 days thereafter, and 9 days after supplementation ceased. Significant differences in ZEN, α-ZOL, β-ZOL, and total ZEN were recorded on different sampling dates. The concentration of inorganic phosphate in DFA III-supplemented animals was significantly higher than in controls on day 23 (8.4 vs. 7.7 mg/dL), suggesting a possible role of DFA III in tight junction of intestinal epithelial cells. This is the first evidence that DFA III reduces mycotoxin levels reaching the systemic circulation and excreted in urine. This preventive effect may involve an improved tight-junction-dependent intestinal barrier function. Additionally, our practical approach confirmed that monitoring of urinary mycotoxin is useful for evaluating the effects of dietary supplements to prevent mycotoxin adsorption.

Difructose dianhydride improves intestinal calcium absorption, wound healing, and barrier function

The gastrointestinal tract (GIT) is critical for nutrient absorption and is an important barrier against harmful pathogens and antigens. Difructose anhydrides (DFA)-IVs are nondigestible disaccharides that enhance calcium and iron absorption by affecting the intestinal epithelial tissue. However, their effects on intestinal functions are not fully understood. In this study, we performed a feeding trial and found that dietary DFA-IVs improved growth performance, relative breast muscle and liver weight, and digestibility and blood calcium and iron concentrations in broilers. Additionally, dietary DFA-IVs increased expression of genes related to growth in the liver, muscle development, and absorption of calcium and iron in the intestine. In vitro experiments revealed that DFA-IV treatment improved intestinal wound-healing (migration, proliferation, and differentiation) after lipopolysaccharide (LPS) challenge in small intestinal epithelial cells. Furthermore, DFA-IV treatment enhanced the intestinal barrier function, which increased the transepithelial electrical resistance (TEER) and decreased the permeability of fluorescein isothiocyanate-dextran (FD-4) after LPS challenge in small intestinal epithelial cells. Collectively, these data indicate that DFA-IV could be used as a feed additive to enhance calcium and iron absorption by affecting the intestinal wound healing and permeability. This study may help improve our understanding of the molecular effects of DFA-IV on the intestine.

Effects of difructose anhydride III on serum immunoglobulin G concentration and health status of newborn Holstein calves during the preweaning period

This experiment was performed to investigate the effects of increases in passively acquired immunoglobulin G (IgG) by difructose anhydride (DFA) III supplementation on subsequent serum IgG concentration and health status in calves during the preweaning period. Thirty newborn female Holstein calves were paired by birth order, and 2 calves in each pair were fed 2 L of the same batch of colostrum within 2 h and at 10 h after birth, and followed by 2 L of the same batch of pooled colostrum at 20 h after birth. One calf from each pair was assigned to the control (n = 15) or treatment (n = 15) group. All calves in the treatment group received 18 g of DFA III at each feeding from birth to 7 d of age, whereas calves in the control group did not receive DFA III. Blood samples were collected before feeding at 0, 10, 20, and 36 h, and 4 and 7 d of age, and sampling was repeated at 7-d intervals thereafter until 49 d of age for serum IgG analysis. Calves were monitored daily for diarrhea and respiratory diseases. Serum IgG concentrations peaked at 36 h of age in both groups. Apparent efficiency of IgG absorption and peak serum IgG concentration were higher in the treatment group than in the control group. Using multiple regression analysis, we showed that peak serum IgG concentration in the newborn calves was positively correlated with colostral IgG concentration and DFA III supplementation. Moreover, peak serum IgG concentration (36 h of age) positively influenced subsequent serum IgG concentration until 35 d of age for all calves in both groups. The treatment group had higher serum IgG concentration from 20 h to 21 d of age than the control group. However, we detected no differences between the groups in number of calves with diarrhea or respiratory disease.

Influence of dairy by-product waste milk on the microbiomes of different gastrointestinal tract components in pre-weaned dairy calves

The community structure of colonised bacteria in the gastrointestinal tracts (GITs) of pre-weaned calves is affected by extrinsic factors, such as the genetics and diet of the calves; however, the dietary impact is not fully understood and warrants further research. Our study revealed that a total of 6, 5, 2 and 10 bacterial genera showed biologically significant differences in the GITs of pre-weaned calves fed four waste-milk diets: acidified waste milk, pasteurised waste milk, untreated bulk milk, and untreated waste milk, respectively. Specifically, generic biomarkers were observed in the rumen (e.g., Bifidobacterium, Parabacteroides, Fibrobacter, Clostridium, etc.), caecum (e.g., Faecalibacterium, Oxalobacter, Odoribacter, etc.) and colon (e.g., Megamonas, Comamonas, Stenotrophomonas, etc.) but not in the faeces. In addition, the predicted metabolic pathways showed that the expression of genes related to metabolic diseases was increased in the calves fed untreated waste milk, which indicated that untreated waste milk is not a suitable liquid diet for pre-weaned calves. This is the first study to demonstrate how different types of waste milk fed to pre-weaned calves affect the community structure of colonised bacteria, and the results may provide insights for the intentional adjustment of diets and gastrointestinal bacterial communities.

Facile enzymatic production of difructose dianhydride III from sucrose

A convenient, efficient, and cost-effective approach to the facile enzymatic production of difructose dianhydride (DFA) III from sucrose is described.

Identification of a Novel Di-D-Fructofuranose 1,2':2,3' Dianhydride (DFA III) Hydrolysis Enzyme from Arthrobacter aurescens SK8.001

Previously, a di-D-fructofuranose 1,2’:2,3’ dianhydride (DFA III)-producing strain, Arthrobacter aurescens SK8.001, was isolated from soil, and the gene cloning and characterization of the DFA III-forming enzyme was studied. In this study, a DFA III hydrolysis enzyme (DFA IIIase)-encoding gene was obtained from the same strain, and the DFA IIIase gene was cloned and expressed in Escherichia coli. The SDS-PAGE and gel filtration results indicated that the purified enzyme was a homotrimer holoenzyme of 145 kDa composed of subunits of 49 kDa. The enzyme displayed the highest catalytic activity for DFA III at pH 5.5 and 55°C, with specific activity of 232 U mg^-1. K_m and V_max for DFA III were 30.7 ± 4.3 mM and 1.2 ± 0.1 mM min^-1, respectively. Interestingly, DFA III-forming enzymes and DFA IIIases are highly homologous in amino acid sequence. The molecular modeling and docking of DFA IIIase were first studied, using DFA III-forming enzyme from Bacillus sp. snu-7 as a template. It was suggested that A. aurescens DFA IIIase shared a similar three-dimensional structure with the reported DFA III-forming enzyme from Bacillus sp. snu-7. Furthermore, their catalytic sites may occupy the same position on the proteins. Based on molecular docking analysis and site-directed mutagenesis, it was shown that D207 and E218 were two potential critical residues for the catalysis of A. aurescens DFA IIIase.

Gut Function-Enhancing Properties and Metabolic Effects of Dietary Indigestible Sugars in Rodents and Rabbits

Indigestible sugars (iS) have received particular interest in food and nutrition research due to their prebiotic properties and other health benefits in humans and animals. The main aim of this review article is to summarize the current knowledge regarding digestive and health-enhancing properties of iS such as sugar alcohols, oligosacharides, and polysaccharides, in rodents and rabbits. Besides ameliorating gut health, iS ingestion also elicits laxative effects and stimulate intestinal permeability and fluid secretions, thereby shortening digesta transit time and increasing stool mass and quality. In rodents and rabbits, as hindgut fermenters, consumption of iS leads to an improved nutrient digestibility, too. Cecal fermentation of iS reduces luminal pH and extends wall tissue facilitating absorption of key dietary minerals across hindgut. The microbial fermentation of iS also enhances excessive blood nitrogen (N) flowing into the cecum to be used as N source for bacterial growth, enhancing N retention in cecotrophic animals. This review also highlights the impact of iS on improving lipid metabolism, mainly by lowering cholesterol and triglycerides levels in the blood. The paper serves as an index of the current knowledge of iS effects in rodents and rabbits and also identifies gaps of knowledge that need to be addressed by future research.

Identification of a recombinant inulin fructotransferase (difructose dianhydride III forming) from Arthrobacter sp. 161MFSha2.1 with high specific activity and remarkable thermostability

Difructose dianhydride III (DFA III) is a functional carbohydrate produced from inulin by inulin fructotransferase (IFTase, EC 4.2.2.18). In this work, an IFTase gene from Arthrobacter sp. 161MFSha2.1 was cloned and expressed in Escherachia coli. The recombinant enzyme was purified by metal affinity chromatography. It showed significant inulin hydrolysis activity, and the produced main product from inulin was determined as DFA III by nuclear magnetic resonance analysis. The molecular mass of the purified protein was calculated to be 43 and 125 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and gel filtration, respectively, suggesting the native enzyme might be a homotrimer. The recombinant enzyme showed maximal activity as 2391 units/mg at pH 6.5 and 55 °C. It displayed the highest thermostability among previously reported IFTases (DFA III forming) and was stable up to 80 °C for 4 h of incubation. The smallest substrate was determined as nystose. The conversion ratio of inulin to DFA III reached 81% when 100 g/L inulin was catalyzed by 80 nM recombinant enzyme for 20 min at pH 6.5 and 55 °C. All of these data indicated that the IFTase (DFA III forming) from Arthrobacter sp. 161MFSha2.1 had great potential for industrial DFA III production.

From fructans to difructose dianhydrides

Fructans are the polymers of fructose molecules, normally having a sucrose unit at what would otherwise be the reducing terminus. Inulin and levan are two basic types of simple fructan, which contain β-(2, 1) and β-(2, 6) fructosyl-fructose linkage, respectively. Fructans not only can serve as soluble dietary fibers for food industry, but also may be biologically converted into high-value products, especially high-fructose syrup and fructo-oligosaccharides. In recent years, much attention has been focused on production of difructose dianhydrides (DFAs) from fructans. DFAs are cyclic disaccharides consisting of two fructose units with formation of two reciprocal glycosidic linkages. They are expected to have promising properties and beneficial effects on human health. DFAs can be produced from fructans by fructan fructotransferases. Inulin fructotransferase (IFTase) (DFA III-forming) and IFTase (DFA I-forming) catalyze the DFA III and DFA I production from inulin, respectively, and levan fructotransferase (LFTase) (DFA IV-forming) catalyzes the production of DFA IV from levan. In this article, the DFA-producing microorganisms are summarized, relevant studies on various DFAs-producing enzymes are reviewed, and especially, the comparisons of the enzymes are presented in detail.

Comparison of Yacon (Smallanthus sonchifolius) Tuber with Commercialized Fructo-oligosaccharides (FOS) in Terms of Physiology, Fermentation Products and Intestinal Microbial Communities in Rats

The yacon (Smallanthus sonchifolius) tuber was examined with regard to its prebiotic effects compared with commercialized fructo-oligosaccharides (FOS). A feed containing 10% yacon tuber, which is equivalent to 5% commercialized FOS in terms of the amount of fructo-oligosaccharides (GF2, GF3 and GF4), was administrated to rats for 28 days. The yacon diet changed the intestinal microbial communities beginning in the first week, resulting in a twofold greater concentration of cecal short-chain fatty acids (SCFAs). The SCFA composition differed, but the cecal pH in rats fed yacon tuber was equal to that in rats fed FOS. Serum triglycerides were lower in rats fed yacon compared with rats fed FOS and the control diet. Cecal size was greater with the yacon tuber diet compared with the control diet. The abundant fermentation in the intestines created a selective environment for the intestinal microbiota, which included Lactobacillus acidophilus, Bifidobacterium pseudolongum, Bifidobacterium animalis and Barnesiella spp. according to identification with culture-independent analysis, 16S rRNA gene PCR-DGGE combined with cloning and sequencing. Barnesiella spp. and B. pseudolongum were only found in the rats fed the yacon diet, while L. acidophilus and B. animalis were found in abundance in rats fed both the yacon and FOS diets. The genus Barnesiella has not previously been reported to be associated with yacon or FOS fermentation. We concluded that the physiological and microbiological effects of the yacon tuber were different from those of FOS. Differences in cecal size, blood triglycerides and microbial community profiles including their metabolites (SCFAs) between the yacon tuber and FOS were shown to be more greatly affected by the yacon tuber rather than FOS.

Jerusalem artichoke and chicory inulin in bakery products affect faecal microbiota of healthy volunteers

A study was conducted to test the effects of Jerusalem artichoke inulin (JA) or chicory inulin (CH) in snack bars on composition of faecal microbiota, concentration of faecal SCFA, bowel habit and gastrointestinal symptoms. Forty-five volunteers participated in a double-blind, randomized, placebo-controlled, parallel-group study. At the end of a 7 d run-in period, subjects were randomly assigned to three groups of fifteen subjects each, consuming either snack bars with CH or JA, or snack bars without fructans (placebo); for 7 d (adaptation period), they ingested one snack bar per day (7.7 g fructan/d) and continued for 14 d with two snack bars per day. The composition of the microbiota was monitored weekly. The consumption of CH or JA increased counts of bifidobacteria (+1.2 log10 in 21 d) and reduced Bacteroides/Prevotella in number and the Clostridium histolyticum/C. lituseburense group in frequency at the end of intervention (P < 0.05). No changes in concentration of faecal SCFA were observed. Consumption of snack bars resulted in a slight increase in stool frequency. Stool consistency was slightly affected in subjects consuming two snack bars containing CH or JA per day (P < 0.05). Consumption of CH or JA resulted in mild and sometimes moderate flatulence in a few subjects compared to placebo (P < 0.05). No structural differences were detected between CH and JA before and after processing. In conclusion, adaptation on increased doses of CH or JA in bakery products stimulates the growth of bifidobacteria and may contribute to the suppression of potential pathogenic bacteria.

Succession in the intestinal microbiota of preadolescent turkeys

In the present study, automated ribosomal intergenic spacer analysis (ARISA), library sequence analysis, real-time PCR detection of Bacteroides uniformis and Campylobacter coli and dot-blot hybridizations of Clostridiaceae were used to identify trends in microbial colonization of the ceca of male turkeys. Two separate trials were performed with six and five birds, respectively. ARISA community profiles identified a period of community transition at week 12 of age in both trials. A significant increase of Ca. coli was also detected at week 12 in one trial, suggesting a possible correlation between microbiota destabilization and pathogen prevalence. Libraries of ribosomal small subunit 16S genes representing weeks 9, 11, 12 and 14 of both trials were sequenced. Whereas fingerprint and sequence analyses indicated significant differences in the species composition between the two trials, in general sequence library and dot-blot analyses indicated that Clostridia-like species decreased in prevalence over time. While B. uniformis prevalence in the two trials rose from 7% and 0% of the library clones at week 9 to 84% and 79% at week 11, real-time PCR did not support these results, with only approximately twofold and sixfold increases in internal transcribed spacer copy numbers observed.

Production of equol from daidzein by gram-positive rod-shaped bacterium isolated from rat intestine

Isoflavones (mainly daidzein and genistin) belong to the flavonoid group of compounds and are classified as phytoestrogens. In the intestine, daidzin is converted to daidzein by beta-glucosidase, and then daidzein is converted to O-desmethylangolensin (O-DMA) or equol via dihydrodaidzein by enzymes of intestinal bacteria. We isolated, for the first time, an anaerobic gram-positive rod-shaped strain capable of producing equol from daidzein. Its 16S rDNA gene sequence (1428 bp) showed 99% similarity with that of the human intestinal bacterium SNU-Julong 732 (AY310748) and 93% similarity with that of Eggerthella lenta ATCC 25559(T) (AF292375). This strain converted daidzein to equol via dihydrodaidzein in an equol-assay medium anaerobically. The addition of butyric acid and arginine increased the conversion ratio of daidzein to equol 4.7- and 4.5-fold, respectively.

Different effects of difructose anhydride III and inulin-type fructans on caecal microbiota in rats

The effects of different kinds of inulin-type fructans on caecal microbiota were evaluated in rats. Four groups of male Wistar rats were fed either a control diet, or diets containing 5% inulin, 5% fructooligosaccharides (FOS), or 5% difructose anhydride III (DFAIII) for two weeks. In the DFAIII group, caecal propionate, butyrate, counts of bifidobacteria, and total anaerobes were lower than in the inulin group, while caecal propionate, succinate, counts of bifidobacteria, and total anaerobes were lower than in the FOS group. Compared to controls, in the DFAIII group the counts of clostridia in caecum were increased by 3 log units. However, this change was statistically not significant. There were no differences between inulin and FOS groups for the pool of short chain fatty acids in caecum and bacterial counts. Results indicate that DFAIII has different effects on caecal microbiota compared to inulin and FOS and that these differences are most likely due to the alpha(3-->2) bonds in DFAIII.

Effects of long-term ingestion of difructose anhydride III (DFA III) on intestinal bacteria and bile acid metabolism in humans

Changes in the intestinal microbiota of 10 human subjects with long-term ingestion of 3 g/d difructose anhydride III (DFA III; 4 persons, 2 months; 3 persons, 6 months; and 3 persons, 12 months) were examined by denaturing gradient gel electrophoresis (DGGE). According to the answers to questionnaires, the subjects were divided into two groups (constipated and normal). The DGGE profile was different for every individual and each subject had unique profiles of intestinal microbiota. In the DGGE profiles of constipated subjects, the intensities of bands related to Bacteroides spp. increased. Moreover, the DFA III-assimilating bacteria, Ruminococcus sp. were isolated from subjects who ingested DFA III for 12 months. These strains showed 95% similarity of their 16S rDNA sequences with that of Ruminococcus obeum ATCC 29174(T) (X85101) and produced large amounts of acetic acid. DFA III ingestion for 2 months tended to increase total organic acids in feces, and tended to decrease fecal pH and the secondary bile acid (SBA) ratio in total bile acids. The SBA ratio in total bile acids corresponded to fecal pH. The production of SBA was decreased by low pH in vitro. These results indicated that DFA III ingestion in humans tended to lower intestinal pH, inhibited bile acid 7alpha-dehydroxylation activities and also tended to decrease the SBA ratios in total bile acids. Moreover, as another cause for the decrease in the SBA ratio in total bile acids, it was suggested that the number of bile acid 7alpha-dehydroxylating bacteria were decreased by DFA III ingestion.

The o-xylylene protecting group as an element of conformational control of remote stereochemistry in the synthesis of spiroketals

Protection of trans-1,2-diol segments as cyclic o-xylylene ethers strongly favours diequatorial over diaxial dispositions; the possibility of using this grouping for remote control of the stereochemistry in the synthesis of spiroketals is here demonstrated by the stereoselective synthesis of tricyclic spirodisaccharides (di-D-fructose dianhydrides).

Effects of difructose anhydride III (DFA III) administration on bile acids and growth of DFA III-assimilating bacterium Ruminococcus productus on rat intestine

The growth of DFA III-assimilating bacteria in the intestines of rats fed 3% DFA III for 2 weeks was examined. Sixty-four percent of the DFA III intake had been assimilated on day 3 of ingestion, and almost all of the DFA III was assimilated at the end of the experiment. The DFA III-assimilating bacterium, Ruminococcus productus, in DFA III-fed rats was in the stationary state of 10(8)-10(9) cells/g dry feces within a week from 10(6) cells/g dry feces on day 1 of DFA III ingestion. The number of R. productus cells was associated with the amount of DFA III excreted in the feces. The acetic acid produced from DFA III by R. productus lowered the cecal pH to 5.8. In control-fed rats and DFA III-fed rats, 94% of secondary bile acids and 94% of primary bile acids, respectively, were accounted for in the total bile acids analyzed. DFA III ingestion increased the ratio of primary bile acids and changed the composition of fecal bile acids. In conclusion, R. productus assimilated DFA III, produced short chain fatty acids, and the cecal pH was lowered. The acidification of rat intestine perhaps inhibited secondary bile acid formation and decreased the ratio of secondary bile acids. Therefore, it is expected that DFA III may prevent colorectal cancer and be a new prebiotic candidate.