Probiotic Bifidobacterium longum supplied with methimazole improved the thyroid function of Graves' disease patients through the gut-thyroid axis.

Graves' disease (GD) is an autoimmune disorder that frequently results in hyperthyroidism and other symptoms. Here, we designed a 6-month study with patients divided into three treatment groups, namely, methimazole (MI, n = 8), MI + black bean (n = 9) and MI + probiotic Bifidobacterium longum (n = 9), to evaluate the curative effects of probiotics supplied with MI on thyroid function of patients with GD through clinical index determination and intestinal microbiota metagenomic sequencing. Unsurprisingly, MI intake significantly improved several thyroid indexes but not the most important thyrotropin receptor antibody (TRAb), which is an indicator of the GD recurrence rate. Furthermore, we observed a dramatic response of indigenous microbiota to MI intake, which was reflected in the ecological and evolutionary scale of the intestinal microbiota. In contrast, we did not observe any significant changes in the microbiome in the MI + black bean group. Similarly, the clinical thyroid indexes of patients with GD in the probiotic supplied with MI treatment group continued to improve. Dramatically, the concentration of TRAb recovered to the healthy level. Further mechanistic exploration implied that the consumed probiotic regulated the intestinal microbiota and metabolites. These metabolites impacted neurotransmitter and blood trace elements through the gut-brain axis and gut-thyroid axis, which finally improved the host's thyroid function.

Study on the regulatory effects and mechanisms of action of bifidobacterial exopolysaccharides on anaphylaxes in mice.

This study used bifidobacterial exopolysaccharides (EPSs) from the selected strains of Bifidobacterium bifidum WBBI01 and WBIN03, Bifidobacterium breve WBBR04, Bifidobacterium infantis WBAN07 and Bifidobacterium longum WBLO01 to explore the EPSs regulatory effect on anaphylaxis in mice. First of all, allergy mouse models were established via subcutaneous injection followed by OVA gavage, and then the EPSs from the five Bifidobacteria were fed into the mice via continuous gavage. Samples were taken from the mice periodically to determine the changes of cytokine levels in serum, including those of IgE, IgG, IL-4, IL-5, IL-13 and INF-γ. The test revealed that the EPSs from B. breve WBBR04 could considerably relieve food allergy in the mouse models, but the effect of B. infantis WBAN07 was unsatisfactory. Based on the above conclusions, the EPSs of B. bifidum WBBR04 and WBIN03, B. breve WBBR04, and B. longum WBLO01 were respectively incubated with the small intestine tissue sections of an allergic mouse model. The resulting culture supernatants were then tested. Based on the above, it can be concluded that EPS of B. breve WBBR04 can enhance the intestinal barrier integrity by attaching themselves onto the inner walls of the small intestine, hence effectively isolating the allergens and preventing food allergy.

Experimental study on synergistic effect of HIFU treatment of tumors using Bifidobacterium bound with cationic phase-change nanoparticles.

OBJECTIVE: Anaerobic bacteria can enter the solid tumor in the hypoxic region to colonize and proliferate. Aggregation of nanoparticles in the tumor area can enhance molecular imaging and therapy. It is hypothesized that the combination of the two could possibly achieve better imaging and tumor treatment. This study presents a biocompatible bacteria-based system that can deliver cationic phase-change nanoparticles (CPNs) into solid tumor to achieve enhanced imaging and treatment integration. MATERIALS AND METHODS: Cationic phase-change nanoparticles (CPNs) and Bifidobacterium longum (BF) were mixed to determine the best binding rate and were placed in an agar phantom for ultrasonography. BF-CPNs complex adhesion to breast cancer cells was observed by laser confocal microscopy. In vivo, BF-CPNs and control groups were injected into tumors in breast cancer nude mouse models. Nanoparticles distribution was observed by ultrasound and in vivo fluorescence imaging. HIFU ablation was performed after injection. Gross and histological changes were compared and synergy was evaluated. RESULTS: Bifidobacterium longum (BF) and CPNs were combined by electrostatic adsorption. The BF-CPNs particles could increase the deposition of energy after liquid-gas phase-change during High Intensity Focused Ultrasound (HIFU) irradiation of tumor. CONCLUSIONS: This study shows a valid method in diagnosis and therapy integration for providing stronger imaging, longer retention time, and more effective tumor treatment.

Preparation and characterization of selenium enriched-Bifidobacterium longum DD98, and its repairing effects on antibiotic-induced intestinal dysbacteriosis in mice.

The aim of this study was to investigate the characteristics of a novel selenium-enriched Bifidobacterium longum DD98 (Se-B. longum DD98) supplement food and its repairing effects on the intestinal ecology of mammals. We assessed the growth, Se accumulation, and Se biotransformation of B. longum DD98 and its effects on antibiotic-induced intestinal dysbacteriosis in mice. The viable bacterial count at the end of fermentation was not significantly affected by the presence of Se. Bifidobacterium longum DD98 took up inorganic Se from the medium and biotransformed it into Se-containing proteins and selenoamino acids. The dominant Se species was selenomethionine (SeMet), which comprised 87% of the total Se in Se-B. longum DD98. Furthermore, Se-B. longum DD98 showed better regulation of the disrupted intestinal microbiota back to normal levels and repaired damaged colon tissues compared to the natural recovery and B. longum DD98 treatments. These findings suggest that B. longum DD98 efficiently biotransformed inorganic Se into more bioactive organic Se forms and may have therapeutic potential for the restoration of antibiotic-induced intestinal dysbacteriosis.

Nanoparticles conjugated with bacteria targeting tumors for precision imaging and therapy.

The hypoxic region microenvironment reduces the susceptibility of the cancer cells to radiotherapy and anticancer drugs of the solid tumors. However, the reduced oxygen surroundings provide an appreciable habitat for anaerobic bacteria to colonize and proliferate. Herein, we present a biocompatible bacteriabased system that can deliver poly(lactic-co-glycolic acid)(PLGA) nanoparticles(PLGA NPs) specifically targeting into solid tumor to achieve precision imaging and treatment. In our strategy, anaerobic bacterium Bifidobacterium longum (B. longum) that colonizes selectively in hypoxic regions of animal body was successfully used as a vehicle to conjugate with PLGA NPs and transported into solid tumors. To improve the efficacy and specificity of tumor therapy, low-boiling point perfluorohexane (PFH) liquid was wrapped in the core of PLGA NPs (PFH/PLGA NPs), which could increase the deposition of energy by affecting the acoustic environment of the tumor and destroy cells after liquid-gas phase transition during High Intensity Focused Ultrasound (HIFU) irradiation. This strategy shows an effective diagnosis and treatment integration for giving stronger imaging, longer retention period and more effective tumor therapy.

Two Novel α-l-Arabinofuranosidases from Bifidobacterium longum subsp. longum Belonging to Glycoside Hydrolase Family 43 Cooperatively Degrade Arabinan.

Arabinose-containing poly- or oligosaccharides are suitable carbohydrate sources for Bifidobacterium longum subsp. longum However, their degradation pathways are poorly understood. In this study, we cloned and characterized the previously uncharacterized glycoside hydrolase family 43 (GH43) enzymes B. longum subsp. longum ArafC (BlArafC; encoded by BLLJ_1852) and B. longum subsp. longum ArafB (BlArafB; encoded by BLLJ_1853) from B. longum subsp. longum JCM 1217. Both enzymes exhibited α-l-arabinofuranosidase activity toward p-nitrophenyl-α-l-arabinofuranoside but no activity toward p-nitrophenyl-ß-d-xylopyranoside. The specificities of the two enzymes for l-arabinofuranosyl linkages were different. BlArafC catalyzed the hydrolysis of α1,2- and α1,3-l-arabinofuranosyl linkages found on the side chains of both arabinan and arabinoxylan. It released l-arabinose 100 times faster from arabinan than from arabinoxylan but did not act on arabinogalactan. On the other hand, BlArafB catalyzed the hydrolysis of the α1,5-l-arabinofuranosyl linkage found on the arabinan backbone. It released l-arabinose from arabinan but not from arabinoxylan or arabinogalactan. Coincubation of BlArafC and BlArafB revealed that these two enzymes are able to degrade arabinan in a synergistic manner. Both enzyme activities were suppressed with EDTA treatment, suggesting that they require divalent metal ions. The GH43 domains of BlArafC and BlArafB are classified into GH43 subfamilies 27 and 22, respectively, but show very low similarity (less than 15% identity) with other biochemically characterized members in the corresponding subfamilies. The B. longum subsp. longum strain lacking the GH43 gene cluster that includes BLLJ_1850 to BLLJ_1853 did not grow in arabinan medium, suggesting that BlArafC and BlArafB are important for assimilation of arabinan.IMPORTANCE We identified two novel α-l-arabinofuranosidases, BlArafC and BlArafB, from B. longum subsp. longum JCM 1217, both of which are predicted to be extracellular membrane-bound enzymes. The former specifically acts on α1,2/3-l-arabinofuranosyl linkages, while the latter acts on the α1,5-l-arabinofuranosyl linkage. These enzymes cooperatively degrade arabinan and are required for the efficient growth of bifidobacteria in arabinan-containing medium. The genes encoding these enzymes are located side by side in a gene cluster involved in metabolic pathways for plant-derived polysaccharides, which may confer adaptability in adult intestines.

Exopolysaccharide from Bifidobacterium longum subsp. longum 35624™ modulates murine allergic airway responses.

Interactions between the host and the microbiota are thought to significantly influence immunological tolerance mechanisms at mucosal sites. We recently described that the loss of an exopolysaccharide (EPS) from Bifidobacterium longum 35624™ eliminated its protective effects in colitis and respiratory allergy murine models. Our goal was to investigate the immune response to purified EPS from B. longum 35624, determine if it has protective effects within the lung and identify the protective mechanisms. Isolated EPS from B. longum 35624 cultures was used for in vitro, ex vivo and in vivo studies. Human monocyte-derived dendritic cells (MDDCs) were used to investigate in vitro immunological responses to EPS. Cytokine secretion, expression of surface markers and signalling pathways were examined. The ovalbumin (OVA) respiratory allergy murine model was used to evaluate the in vivo immunomodulatory potential of EPS. In addition, interleukin (IL)-10 knockout (KO) mice and anti-Toll-like receptor (TLR)-2 blocking antibody were used to examine the underlying protective mechanisms of intranasal EPS administration. Stimulation of human MDDCs with EPS resulted in IL-10 secretion, but not proinflammatory cytokines. IL-10 secretion was TLR-2-dependent. Eosinophil recruitment to the lungs was significantly decreased by EPS intranasal exposure, which was associated with decreased expression of the Th2-associated markers C-C motif chemokine 11 (CCL11), C-C chemokine receptor type 3 (CCR3), IL-4 and IL-13. TLR-2-mediated IL-10 secretion was shown to be required for the reduction in eosinophils and Th2 cytokines. EPS-treatment reduced eosinophil recruitment within the lung in a respiratory inflammation mouse model, which is both TLR-2 and IL-10 mediated. EPS can be considered as a novel molecule potentially reducing the severity of chronic eosinophil-related airway disorders.

Chemical and biological properties of the novel exopolysaccharide produced by a probiotic strain of Bifidobacterium longum.

Bifidobacterium longum W11 is a commercialized probiotic that has an exopolysaccharide (EPS) layer covering its surface which could play a role in the beneficial properties attributed to the strain; thus, we have carried out chemical and biological analyses of this polymer. The eps cluster putatively involved in the polymer synthesis presented a unique structural organization not previously reported in bifidobacteria. B. longum W11 produced a complex polysaccharide blend with the main component composed of glucose and galactose. An exhaustive structural analysis identified two different repeating units: one linear [→6)-ß-Galf-(1→3)-α-Galp-(1→] and one, more abundant, with the same backbone in which the ß-Galf is 5-substituted by a ß-Glcp unit. The antioxidant capability and the lack of toxicity of the whole EPS W11 mixture, as well as some functional characteristics of the producing strain, such as the in vitro resistance to gastrointestinal conditions and the adhesion of colonocytes, were also determined.

The Simple and Unique Allosteric Machinery of Thermus caldophilus Lactate Dehydrogenase : Structure-Function Relationship in Bacterial Allosteric LDHs.

Many bacterial L-lactate dehydrogenases (LDH) are allosteric enzymes, and usually activated by fructose 1,6-bisphosphate (FBP) and often also by substrate pyruvate. The active and inactive state structures demonstrate that Thermus caldophilus, Lactobacillus casei, and Bifidobacterium longum LDHs consistently undergo allosteric transition according to Monod-Wyman-Changeux model, where the active (R) and inactive (T) states of the enzymes coexist in an allosteric equilibrium (pre-existing equilibrium) independently of allosteric effectors. The three enzymes consistently take on open and closed conformations of the homotetramers for the T and R states, coupling the quaternary structural changes with the structural changes in binding sites for substrate and FBP though tertiary structural changes. Nevertheless, the three enzymes undergo markedly different structural changes from one another, indicating that there is a high variety in the allosteric machineries of bacterial LDHs. L. casei LDH undergoes the largest quaternary structural change in the three enzymes, and regulates its catalytic activity though a large linkage frame for allosteric motion. In contrast, T. caldophilus LDH exhibits the simplest allosteric motion in the three enzymes, involving a simple mobile structural core for the allosteric motion. TcLDH likely mediates its allosteric equilibrium mostly through electrostatic repulsion within the protein molecule, providing an insight for regulation machineries in bacterial allosteric LDHs.