Active Hexose-Correlated Compound Shows Direct and Indirect Effects against Chronic Lymphocytic Leukemia.

Chronic lymphocytic leukemia (CLL) is a disease characterized by the accumulation of mature CD19+CD5+CD23+ B cells in the bloodstream and in lymphoid organs. It usually affects people over 70 years of age, which limits the options for treatments. The disease is typically well-managed, but to date is still incurable. Hence, the need for novel therapeutic strategies remains. Nurse-like cells (NLCs) are major components of the microenvironment for CLL, supporting tumor cell survival, proliferation, and even drug resistance. They are of myeloid lineage, guided toward differentiating into their tumor-supportive role by the CLL cells themselves. As such, they are analogous to tumor-associated macrophages and represent a major therapeutic target. Previously, it was found that a mushroom extract, Active Hexose-Correlated Compound (AHCC), promoted the death of acute myeloid leukemia cells while preserving normal monocytes. Given these findings, it was asked whether AHCC might have a similar effect on the abnormally differentiated myeloid-lineage NLCs in CLL. CLL-patient PBMCs were treated with AHCC, and it was found that AHCC treatment showed a direct toxic effect against isolated CLL cells. In addition, it significantly reduced the number of tumor-supportive NLCs and altered their phenotype. The effects of AHCC were then tested in the Eµ-TCL1 mouse model of CLL and the MllPTD/WT Flt3ITD/WT model of AML. Results showed that AHCC not only reduced tumor load and increased survival in the CLL and AML models, but it also enhanced antitumor antibody treatment in the CLL model. These results suggest that AHCC has direct and indirect effects against CLL and that it may be of benefit when combined with existing treatments.

Genotoxicity assessment of 1,4-anhydro-4-seleno-D-talitol (SeTal) in human liver HepG2 and HepaRG cells.

1,4-Anhydro-4-seleno-D-talitol (SeTal) is a highly water-soluble selenosugar with interesting antioxidant and skin-tissue-repair properties; it is highly stable in simulated gastric and gastrointestinal fluids and is a potential pharmaceutical ingredient that may be administered orally. Hepatic toxicity is often a major problem with novel drugs and can result in drug withdrawal from the market. Predicting hepatotoxicity is therefore essential to minimize late failure in the drug-discovery process. Herein, we report in vitro studies to evaluate the cytotoxic and genotoxic potential of SeTal in HepG2 and hepatocyte-like differentiated HepaRG cells. Except for extremely high concentrations (10 mM, 68 h-treatment in HepG2), SeTal did not affect the viability of each cell type. While the highest examined concentrations (0.75 and 1 mM in HepG2; 1 mM in HepaRG) were observed to induce primary DNA damage, SeTal did not exhibit clastogenic or aneugenic activity toward either HepG2 or HepaRG cells. Moreover, no significant cytostasis variations were observed in any experiment. The clearly negative results observed in the CBMN test suggest that SeTal might be used as a potential active pharmaceutical ingredient. The present study will be useful for the selection of non-toxic concentrations of SeTal in future investigations.

Effects of Chemical Structures Interacting with Amine Oxidases on Glucose, Lipid and Hydrogen Peroxide Handling by Human Adipocytes.

Benzylamine is a natural molecule present in food and edible plants, capable of activating hexose uptake and inhibiting lipolysis in human fat cells. These effects are dependent on its oxidation by amine oxidases present in adipocytes, and on the subsequent hydrogen peroxide production, known to exhibit insulin-like actions. Virtually, other substrates interacting with such hydrogen peroxide-releasing enzymes potentially can modulate lipid accumulation in adipose tissue. Inhibition of such enzymes has also been reported to influence lipid deposition. We have therefore studied in human adipocytes the lipolytic and lipogenic activities of pharmacological entities designed to interact with amine oxidases highly expressed in this cell type: the semicarbazide-sensitive amine oxidase (SSAO also known as PrAO or VAP-1) and the monoamine oxidases (MAO). The results showed that SZV-2016 and SZV-2017 behaved as better substrates than benzylamine, releasing hydrogen peroxide once oxidized, and reproduced or even exceeded its insulin-like metabolic effects in fat cells. Additionally, several novel SSAO inhibitors, such as SZV-2007 and SZV-1398, have been evidenced and shown to inhibit benzylamine metabolic actions. Taken as a whole, our findings reinforce the list of molecules that influence the regulation of triacylglycerol assembly/breakdown, at least in vitro in human adipocytes. The novel compounds deserve deeper investigation of their mechanisms of interaction with SSAO or MAO, and constitute potential candidates for therapeutic use in obesity and diabetes.

Surface-functionalized curcumin-loaded polymeric nanocapsules could block apomorphine-induced behavioral changes in rats.

BACKGROUND: Surface functionalization enhances the properties and characteristics of polymeric nanocapsules (NCs) mainly due to the surface charge, surfactants, and polymer coating type. Curcumin (CUR) is a bioactive compound with several proven pharmacological properties and low bioavailability. This study aimed to develop anionic (poly-ɛ-caprolactone; PCL) and cationic (Eudragit® RS100 (EUD)) NCs prepared with sorbitan monostearate (Span 60®) or sorbitan monooleate (Span 80®), coated with d-α-tocopherol polyethylene glycol 1000 succinate (TPGS) and optimized using 23 factorial analysis. Subsequently, the biological activity was evaluated. METHODS: A two-level, three-factor design (polymer, Span type, and TPGS concentration) was used. The biological effects of CUR-loaded TPGS-coated cationic and anionic NCs were assessed in apomorphine-induced stereotyped behavior in rats. RESULTS: The type of polymer (anionic or cationic) and Span® had a factorial influence on the physical and chemical characteristics of NCs according to the changes in TPGS concentrations. Both cationic and anionic CUR-NCs could block apomorphine-induced behavioral changes. CONCLUSIONS: The CUR-loaded TPGS-coated NCs proved to be a promising brain delivery system.

Análisis comparativo de respuesta glicémica y de péptido C, tras la ingesta de estevia y D-tagatosa, según habitualidad de consumo de edulcorantes no nutritivos y preferencias alimentarias reportadas por mujeres con resistencia a la insulina / Comparative analysis of glicemic response and c peptide, after comsumption of stevia and d tagatosa, according to regular compsumtion of not nutritive sweeteners andnourish preferences reported by woman with insuline resistance

INTRODUCCIÓN: El consumo de edulcorantes no nutritivos (ENN) ha ido en aumento. A pesar de ello, se desconoce el efecto entre el consumo habitual de ENN y las preferencias alimentarias con parámetros bioquímicos en pacientes con resistencia a la insulina. OBJETIVO: Comparar la respuesta glicémica y de péptido C, según habitualidad de consumo de edulcorantes y preferencias alimentarias reportados por mujeres con resistencia a la insulina tras la ingesta de estevia y D-tagatosa. MÉTODOS: Treinta y tres mujeres con RI se sometieron a una encuesta de opción múltiple sobre preferencias alimentarias y ETCC modificada de edulcorantes. Aleatoriamente recibieron una precarga de control o experimental (estevia y D-tagatosa) donde se midió glicemia y péptido C en los tiempos -10, 30, 60, 90, 120, 180. RESULTADOS: Se encontró un ABC de péptido C más alto después de la ingesta de D-tagatosa (p = 0,02) en pacientes que prefieren alimentos ricos en proteínas en comparación con aquellos que prefieren alimentos ricos en grasas o en carbohidratos simples. Se observó un mayor ABC de péptido C (p = 0,04) para la prueba control en quienes prefieren el sabor salado y consumen menor cantidad de ENN, sin diferencias significativas entre quienes prefirieron sabor dulce. CONCLUSIONES: Al comparar las respuestas glicémicas e insulinémicas entre habitualidad de consumo de edulcorantes y preferencias alimentarias reportados por las pacientes tras la ingesta de agua, estevia y D-Tagatosa, no se obtuvieron diferencias significativas. Salvo en quienes preferían alimentos ricos en proteínas tras la ingesta de D- tagatosa y quienes preferían sabor salado con menor consumo habitual de ENN tras ingesta control.

INTRODUCTION: The consumption of non-nutritive sweeteners (NNS) has been increasing. Despite this, the effect between the habitual consumption of ENN and food preferences with biochemical parameters in patients with insulin resistance is unknown. OBJECTIVE: To compare the glycemic and C-peptide response, according to the habitual consumption of sweeteners and food preferences reported by women with insulin resistance after ingesting stevia and D-tagatose. METHODS: Thirty-three women with IR underwent a multiple choice survey on food preferences and modified ETCC for sweeteners. They randomly received a control or experimental preload (stevia and D-tagatose) where glycemia and peptide C were measured at times -10, 30, 60, 90, 120, 180. RESULTS: A higher C-peptide AUC was found after ingestion of D-tagatose (p = 0.02) in patients who prefer foods rich in protein compared to those who prefer foods rich in fat or simple carbohydrates. A higher AUC of peptide C (p = 0.04) is performed for the control test in those who prefer a salty taste and consume a lower amount of ENN, without significant differences between those who prefer a sweet taste. CONCLUSION: When comparing the glycerol and insulin responses between the habitual consumption of sweeteners and the food preferences reported by the patients after the ingestion of water, stevia and D-Tagatose, no significant differences were obtained. Except in those who prefer foods rich in protein after ingesting D-tagatose and those who prefer salty taste with less habitual consumption of NNS after control intake.

A gulose moiety contributes to the belomycin (BLM) disaccharide selective targeting to lung cancer cells.

Eight mono- or disaccharide analogues derived from BLM disaccharide, along with the corresponding carbohydate-dye conjugates have been designed and synthesized in this study, aiming at exploring the effect of a gulose residue on the cellular binding/uptake of BLM disaccharide and it possible uptake mechanism. Our evidence is presented indicating that, for the cellular binding/uptake of BLM disaccharide, a gulose residue is an essential subunit but unrelated to its chemical nature. Interestingly, d-gulose-dye conjugate is able to selectively target A549 cancer cells, but l-gulose-dye conjugate fails. Further uptake mechanism studies demonstrate d-gulose-dye derivatives similar to BLM disaccharide-dye ones behave in a temperature- and ATP-dependent manner, and are partly directed by the GLUT1 receptor. Moreover, d-gulose modifying gemcitabine 53a exhibits more potent antitumor activity compared to derivatives 53b-c in which gemcitabine is decorated with other monosaccharides. Taken together, the monosacharide d-gulose conjugate offers a new strategy for solving cytotoxic drugs via the increased tumor targeting in the therapy of lung cancer.

Interactions of tagatose with the sugar metabolism are responsible for Phytophthora infestans growth inhibition.

Tagatose is a rare sugar metabolised by a limited number of microorganisms that inhibits a large spectrum of phytopathogens. In particular, tagatose inhibited Phytophthora infestans growth and negatively affected mitochondrial processes. However, the possible effects of tagatose on P. infestans metabolism have not yet been investigated. The aim of this study was to analyse the impact of this rare sugar on the sugar metabolism in P. infestans, in order to better understand its mode of action. Tagatose inhibited the growth of P. infestans with a precise reprogramming of the carbohydrate metabolism that involved a decrease of glucose, glucose-1-phosphate and mannose content and ß-glucosidase activity. The combination of tagatose with common sugars led to three different responses and highlighted antagonistic interactions. In particular, glucose partially attenuated the inhibitory effects of tagatose, while fructose fully impaired tagatose-mediated growth inhibition and metabolite changes. Moreover, sucrose did not attenuate tagatose effects, suggesting that the inhibition of sucrose catabolism and the alteration of glucose-related pathways contributed to the growth inhibition caused by tagatose to P. infestans. The interactions of tagatose with the common sugar metabolism were found to be a key mode of action against P. infestans growth, which may represent the basis for the further development of tagatose as an eco-friendly fungicide.

Active Hexose-Correlated Compound Restores Gene Expression and Protein Secretion of Protective Cytokines of Immune Cells in a Murine Stress Model during Chlamydia muridarum Genital Infection.

Chlamydia trachomatis genital infection is the most common bacterial sexually transmitted disease worldwide. Previously, we reported that cold-induced stress results in immune suppression of mice that subsequently leads to increased intensity of Chlamydia muridarum genital infection. Furthermore, we demonstrated that stressed mice orally fed with active hexose-correlated compound (AHCC) have reduced shedding of C. muridarum from the genital tract. However, the mechanism of AHCC in reducing the organ load and changing the immune response in the stress model is not well known. This study evaluated infection and changes in immunological parameters of stressed AHCC-fed mice with or without C. muridarum genital infection. We hypothesized that AHCC feeding to stressed mice restores protective immune function and reduces susceptibility to C. muridarum genital infection. The results show that oral feeding of stressed mice with AHCC resulted in decreased shedding of C. muridarum from the genital tract, reduced production of plasma catecholamines, increased expression of T-bet and reduced GATA-3 in CD4+ T cells, increased production of interleukin-12 (IL-12) and interferon gamma (IFN-γ) and reduced production of IL-4 in CD4+ T cells, and enhanced expression of surface markers and costimulatory molecules of CD4+ T cells, bone marrow-derived dendritic cells (BMDCs), and natural killer cells. Coculturing of mature BMDCs with splenic CD4+ T cells led to the increased and decreased production of T helper 1 and T helper 2 cytokines, respectively. Overall, our results show that AHCC fosters the restoration of Th1 cytokine production while reducing Th2 cytokine production, which would promote C. muridarum clearance in the murine stress model.

Evaluation of Antimicrobial Effect of Air-Polishing Treatments and Their Influence on Human Dental Pulp Stem Cells Seeded on Titanium Disks.

Dental implants are one of the most frequently used treatment options for tooth replacement, and titanium is the metal of choice due to its demonstrated superiority in resisting corrosion, lack of allergic reactions and mechanical strength. Surface roughness of titanium implants favors the osseointegration process; nevertheless, its topography may provide a suitable substrate for bacterial biofilm deposition, causing peri-implantitis and leading to implant failure. Subgingival prophylaxis treatments with cleansing powders aimed to remove the bacterial accumulation are under investigation. Two different air-polishing powders-glycine and tagatose-were assayed for their cleaning and antimicrobial potential against a Pseudomonas biofilm and for their effects on human dental pulp stem cells (hDPSCs), seeded on sandblasted titanium disks. Immunofluorescence analyses were carried out to evaluate cell adhesion, proliferation, stemness and osteogenic differentiation. The results demonstrate that both the powders have a great in vitro cleaning potential in the early period and do not show any negative effects during hDPSCs osteogenic differentiation process, suggesting their suitability for enhancing the biocompatibility of titanium implants. Our data suggest that the evaluated cleansing systems reduce microbial contamination and allow us to propose tagatose as an adequate alternative to the gold standard glycine for the air-polishing prophylaxis treatment.

The rare sugar D-tagatose protects plants from downy mildews and is a safe fungicidal agrochemical.

The rare sugar D-tagatose is a safe natural product used as a commercial food ingredient. Here, we show that D-tagatose controls a wide range of plant diseases and focus on downy mildews to analyze its mode of action. It likely acts directly on the pathogen, rather than as a plant defense activator. Synthesis of mannan and related products of D-mannose metabolism are essential for development of fungi and oomycetes; D-tagatose inhibits the first step of mannose metabolism, the phosphorylation of D-fructose to D-fructose 6-phosphate by fructokinase, and also produces D-tagatose 6-phosphate. D-Tagatose 6-phosphate sequentially inhibits phosphomannose isomerase, causing a reduction in D-glucose 6-phosphate and D-fructose 6-phosphate, common substrates for glycolysis, and in D-mannose 6-phosphate, needed to synthesize mannan and related products. These chain-inhibitory effects on metabolic steps are significant enough to block initial infection and structural development needed for reproduction such as conidiophore and conidiospore formation of downy mildew.

Molecular process of glucose uptake and glycogen storage due to hamamelitannin via insulin signalling cascade in glucose metabolism.

Understanding the mechanism by which the exogenous biomolecule modulates the GLUT-4 signalling cascade along with the information on glucose metabolism is essential for finding solutions to increasing cases of diabetes and metabolic disease. This study aimed at investigating the effect of hamamelitannin on glycogen synthesis in an insulin resistance model using L6 myotubes. Glucose uptake was determined using 2-deoxy-D-[1-3H] glucose and glycogen synthesis were also estimated in L6 myotubes. The expression levels of key genes and proteins involved in the insulin-signaling pathway were determined using real-time PCR and western blot techniques. The cells treated with various concentrations of hamamelitannin (20 µM to 100 µM) for 24 h showed that, the exposure of hamamelitannin was not cytotoxic to L6 myotubes. Further the 2-deoxy-D-[1-3H] glucose uptake assay was carried out in the presence of wortmannin and Genistein inhibitor for studying the GLUT-4 dependent cell surface recruitment. Hamamelitannin exhibited anti-diabetic activity by displaying a significant increase in glucose uptake (125.1%) and glycogen storage (8.7 mM) in a dose-dependent manner. The optimum concentration evincing maximum activity was found to be 100 µm. In addition, the expression of key genes and proteins involved in the insulin signaling pathway was studied to be upregulated by hamamelitannin treatment. Western blot analysis confirmed the translocation of GLUT-4 protein from an intracellular pool to the plasma membrane. Therefore, it can be conceived that hamamelitannin exhibited an insulinomimetic effect by enhancing the glucose uptake and its further conversion into glycogen by regulating glucose metabolism.

Engineering and biological assessment of double core nanoplatform for co-delivery of hybrid fluorophores to human melanoma.

We investigated new development in photodynamic therapy (PDT), aiming at enhanced tumor selectivity and biocompatibility, which included application of a third-generation photosensitizing agent, i.e. xanthene-origin Rose Bengal (RB) co-encapsulated with up-converting NaYF4 nanoparticles (NPs) co-doped with lanthanide ions: Er3+ (2%) and Yb3+ (20%). The hybrid fluorophores were applied as components of double core nanocarriers (NCs) obtained by double (multiple) emulsion solvent evaporation process. Next, to improve the biocompatibility and photodynamic activity, biodegradable polymer: poly(lactide-co-glycolide) - PLGA and non-ionic surfactants with different hydrophobicity: Span 80 and Cremophor A25, were used. After the engineering process, controlled by dynamic light scattering (DLS) measurements, ζ-potential evaluation, transmission electron and atomic force microscopy (TEM and AFM) imaging, as well as optical analysis provided by measurements of the up-conversion emission spectra and luminescence kinetics for encapsulated only NaYF4:Er3+,Yb3+ NPs and co-encapsulated RB + NaYF4:Er3+,Yb3+ molecules, spherical polyester NCs with average size <200 nm, were tested on human melanoma (Me-45 and MeWo) cells and a control human keratinocyte (HaCaT) cell line. The photodynamic action of the investigated NCs was assessed by oxidoreductive potential measurements with 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, that corresponds to percentage of the viable cells. Immunofluorescence and the NCs internalization studies were visualized by confocal laser scanning microscopy (CLSM studies). Our results indicated effective photosensitizer delivery into the cancer cells and significant photodynamic efficiency enhanced by the near infrared (NIR)-activation of the encapsulated hybrid cargo in the skin melanoma cells.

Self-nanoemulsifying drug delivery system to improve transcorneal permeability of voriconazole: in-vivo studies.

OBJECTIVE: This study investigates the effectiveness of self-nanoemulsifying drug delivery system (SNEDDS) in improving voriconazole transcorneal permeability. METHODS: Voriconazole-SNEDDS was prepared with isopropyl myristate, PEG 400, Tween 80® and Span 80® and was subjected for physicochemical characterization after reconstitution with NaCl 0.9% (1/9; v/v). In-vitro antifungal activity was assessed and compared with the marketed formulation. In-vivo studies, namely ocular irritation test via modified Draize test and pharmacokinetic study, were investigated using rabbit as animal model. KEY FINDINGS: Voriconazole-SNEDDS presented a droplet size of 21.353 ± 0.065 nm, a polydispersity index of 0.123 ± 0.003, a pH of 7.205 ± 0.006 and an osmolarity of 342.667 ± 2.517 mOsmol/l after reconstitution with NaCl 0.9%. Voriconazole-SNEDDS minimum inhibitory concentration (MIC90 ) was similar to the one of marketed formulation for Candida species while it was significantly lower (P < 0.001) for Aspergillus fumigatus. Draize test revealed that Voriconazole-SNEDDS was safe for ocular administration. Voriconazole maximum concentration (5.577 ± 0.852 µg/ml) from SNEDDS was higher than marketed formulation (Cmax  = 4.307 ± 0.623 µg/ml), and the Tmax was delayed to 2 h. The area under the concentration-time curve value of Voriconazole-SNEDDS was improved by 2.419-fold. CONCLUSION: Our results suggest that SNEDDS is a promising carrier for voriconazole ocular delivery and this encourages further clinical studies.

Docetaxel-loaded solid lipid nanoparticles prevent tumor growth and lung metastasis of 4T1 murine mammary carcinoma cells.

BACKGROUND: Metastasis causes the most breast cancer-related deaths in women. Here, we investigated the antitumor effect of solid lipid nanoparticles (SLN-DTX) when used in the treatment of metastatic breast tumors using 4T1-bearing BALB/c mice. RESULTS: Solid lipid nanoparticles (SLNs) were produced using the high-energy method. Compritol 888 ATO was selected as the lipid matrix, and Pluronic F127 and Span 80 as the surfactants to stabilize nanoparticle dispersion. The particles had high stability for at least 120 days. The SLNs' dispersion size was 128 nm, their polydispersity index (PDI) was 0.2, and they showed a negative zeta potential. SLNs had high docetaxel (DTX) entrapment efficiency (86%), 2% of drug loading and showed a controlled drug-release profile. The half-maximal inhibitory concentration (IC50) of SLN-DTX against 4T1 cells was more than 100 times lower than that of free DTX after 24 h treatment. In the cellular uptake test, SLN-DTX was taken into the cells significantly more than free DTX. The accumulation in the G2-M phase was significantly higher in cells treated with SLN-DTX (73.7%) than in cells treated with free DTX (23.0%), which induced subsequent apoptosis. TEM analysis revealed that SLN-DTX internalization is mediated by endocytosis, and fluorescence microscopy showed DTX induced microtubule damage. In vivo studies showed that SLN-DTX compared to free docetaxel exhibited higher antitumor efficacy by reducing tumor volume (p < 0.0001) and also prevented spontaneous lung metastasis in 4T1 tumor-bearing mice. Histological studies of lungs confirmed that treatment with SLN-DTX was able to prevent tumor. IL-6 serum levels, ki-67 and BCL-2 expression were analyzed and showed a remarkably strong reduction when used in a combined treatment. CONCLUSIONS: These results indicate that DTX-loaded SLNs may be a promising carrier to treat breast cancer and in metastasis prevention.

Effects of a novel selenium substituted-sugar (1,4-anhydro-4-seleno-d-talitol, SeTal) on human coronary artery cell lines and mouse aortic rings.

Chronic low-grade inflammation and oxidative damage are strongly associated with pathologies including cardiovascular disease. As a consequence, there is considerable interest in agents that mitigate damage. Selenium compounds can act as potent protective agents against oxidation due to the high reactivity and nucleophilicity of the selenium atom. 1,4-Anhydro-4-seleno-d-talitol (SeTal, a novel water-soluble selenium-based sugar) is a potent oxidant scavenger in vitro and in human plasma. Here we show that SeTal is highly stable in solutions that mimic biological fluids and the gastrointestinal tract, and is not rapidly degraded or metabolized unlike some other selenium-containing compounds. SeTal remains intact during extended storage, and it rapidly penetrates into, and effluxes from, primary human coronary artery endothelial and smooth muscle cells, but does not induce loss of metabolic activity, or modulate cell survival and growth rates at concentrations ≤2 mM. Steady-state intracellular concentrations can reach 2-10 µM. SeTal affords protection against H2O2- and HOCl-mediated oxidative damage, with this being independent of the concentration or activities of the selenium-dependent protective enzymes TrxR and GPx. Protection was observed with both concurrent drug and oxidant administration and also (to a lesser extent) with cellular pre-loading. SeTal also affords protection to isolated arterial segments, with the compound decreasing HOCl (50 µΜ) mediated effects on aortic ring relaxation, consistent with the preservation of NO bioavailability. The stability, bioavailability and protective actions of this compound, suggest that it is worthy of further investigation as a protective agent, particularly in the area of cardiovascular disease.

Ecological impact of a rare sugar on grapevine phyllosphere microbial communities.

Plants host a complex microbiota inside or outside their tissues, and phyllosphere microorganisms can be influenced by environmental, nutritional and agronomic factors. Rare sugars are defined as monosaccharides with limited availability in nature and they are metabolised by only few certain microbial taxa. Among rare sugars, tagatose (TAG) is a low-calories sweetener that stimulates and inhibits beneficial and pathogenic bacteria in the human gut microbiota, respectively. Based on this differential effect on human-associated microorganisms, we investigated the effect of TAG treatments on the grapevine phyllosphere microorganisms to evaluate whether it can engineer the microbiota and modify the ratio between beneficial and pathogenic plant-associated microorganisms. TAG treatments changed the structure of the leaf microbiota and they successfully reduced leaf infections of downy mildew (caused by Plasmopara viticola) and powdery mildew (caused by Erysiphe necator) under field conditions. TAG increased the relative abundance of indigenous beneficial microorganisms, such as some potential biocontrol agents, which could partially contribute to disease control. The taxonomic composition of fungal and bacterial leaf populations differed according to grapevine locations, therefore TAG effects on the microbial structure were influenced by the composition of the originally residing microbiota. TAG is a promising biopesticide that could shift the balance of pathogenic and beneficial plant-associated microorganisms, suggesting selective nutritional/anti-nutritional properties for some specific taxa. More specifically, TAG displayed possible plant prebiotic effects on the phyllosphere microbiota and this mechanism of action could represent a novel strategy that can be further developed for sustainable plant protection.

The Constipation-Relieving Property of d-Tagatose by Modulating the Composition of Gut Microbiota.

d-tagatose, a monosaccharide as well as a dietary supplement, has been reported as having a wide range of applicability in the food industry, however, the prebiotic activity, anticonstipation effects, and related mechanisms are still unclear. In this study, using the loperamide-induced constipation Kunming mice as the animal model, the effects of d-tagatose for the prevention of constipation were evaluated by gastrointestinal transit experiment and defecation experiment. Furthermore, the underlying mechanism was clarified by evaluating the change of the biochemical indicators and analyzing 16S rRNA amplicon of gut microbiota among the different mice groups. The results showed that the gastrointestinal transit rate, fecal number, and weight in six hours were significantly enhanced after the administration of d-tagatose. In addition, d-tagatose significantly increased the serum levels of acetylcholine (Ach) and substance P (SP), whereas the serum levels of nitric oxide (NO) were significantly decreased. Moreover, the 16S rRNA sequencing analysis revealed that the changes in the gut microbiota caused by constipation were restored by d-tagatose treatment. In conclusion, this study indicated that the administration of d-tagatose as a dietary supplement can effectively prevent and relieve constipation in Kunming mice, and it is a promising prebiotic candidate with constipation-relieving properties.

Comparative Study of Aryl O-, C-, and S-Mannopyranosides as Potential Adhesion Inhibitors toward Uropathogenic E. coli FimH.

A set of three mannopyranoside possessing identical 1,1'-biphenyl glycosidic pharmacophore but different aglyconic atoms were synthesized using either a palladium-catalyzed Heck cross coupling reaction or a metathesis reaction between their corresponding allylic glycoside derivatives. Their X-ray structures, together with their calculated 3D structures, showed strong indicators to explain the observed relative binding abilities against E. coli FimH as measured by a improved surface plasmon resonance (SPR) method. Amongst the O-, C-, and S-linked analogs, the C-linked analog showed the best ability to become a lead candidate as antagonist against uropathogenic E. coli with a Kd of 11.45 nM.

Efectos de la ingesta de los edulcorantes estevia y D-tagatosa sobre el metabolismo de la glucosa, ácido úrico y apetito-saciedad / Effects of stevia and D-tagatose sweeteners intake om glucose, uric acid metabolism and appetite-satiety

INTRODUCCIÓN: Si bien, los edulcorantes no nutritivos (ENN) estevia y D-tagatosa han sido reportados como seguros, han demostrado tener algunos efectos metabólicos tras su ingesta. OBJETIVO: Describir los efectos de la ingesta de estevia y D-tagatosa sobre el metabolismo de la glucosa y ácido úrico, y del apetito-saciedad, a partir de la evidencia disponible. MÉTODOS: Revisión descriptiva. Se realizó búsqueda en PubMed utilizando los siguientes términos y palabras clave: "stevia rebaudiana", "tagatose", "D-tagatose", "blood glucose", "insulin", "metabolic processes", "uric acid", "hyperuricemia", "appetite" o "satiety". El análisis de los estudios seleccionados fue discrecional. RESULTADOS: Existen estudios que demuestran efectos beneficiosos tras el consumo de estevia o D-tagatosa sobre el control glicémico, apetito y saciedad tanto en sujetos sanos como con alteraciones en el metabolismo de la glucosa. Por otra parte, un número importante de estudios que evalúan la ingesta de estevia reportan efectos nulos sobre dichos parámetros. En relación al ácido úrico, solo un estudio en sujetos con enfermedad renal crónica reporta aumento en la concentración de ácido úrico plasmático tras la ingesta de 500 mg/día de estevia. Pocos estudios han evaluado el efecto de la ingesta de D-tagatosa sobre uricemia, en sujetos sanos y diabéticos, reportando un aumento transitorio y significativo en los niveles de ácido úrico sérico, sin embargo, no se ha logrado demostrar un efecto hiperuricémico asociado. Es importante destacar que la metodología de los estudios revisados es heterogénea, especialmente en relación al tamaño muestral, tiempo, dosis y vía de adminitración del edulcorante. CONCLUSIÓN: La ingesta de estevia y D-tagatosa ha demostrado efectos beneficiosos sobre el metabolismo de la glucosa, el apetito y la saciedad. El efecto del consumo de D-tagatosa sobre ácido úrico sérico requiere mayor evidencia para demostrar su significancia clínica.

INTRODUCTION: No-nutritive sweeteners stevia and D-tagatose have been reported as safe according to their acceptable daily intake, however, they have been shown to have metabolic effects after their ingestion. OBJECTIVE: To describe the effects of stevia and D-tagatose intake on parameters associated to glucose, uric acid metabolism and on appetite-satiety, considering the available evidence. METHODS: Descriptive review. PubMed search was carried out to identify the totality of the published articles. The following terms and key words were used: "stevia rebaudiana", "tagatose", "D-tagatose", "blood glucose", "insulin", "metabolic processes", "uric acid", "hyperuricemia", "appetite" o "satiety". The analysis of the selected studies was discretionary. RESULTS: studies have shown beneficial effects of stevia and D-tagatose consumption on glycemic control, appetite and satiety in healthy subjects as well as subjects with impairment glucose metabolism. On the other hand, a significant number of studies evaluating estevia intake report null effects on these parameters. In relation to uric acid, only one study in subjects with chronic kidney disease reported an increase in plasmatic uric acid concentration after the intake of 500 mg/day of stevia. Several studies have evaluated the effect of D-tagatose intake on plasmatic uric acid, in healthy and diabetic subjects, reporting a transient and significant increase in serum uric acid levels, however, has not been able to demonstrate an associated hyperuricemic effect. It is important to highlight that the methodology of the studies reviewed is heterogeneous, especially in relation to sample size, dose administered, time and route of exposure to the sweetener. CONCLUSION: Stevia and D-tagatose intake has shown beneficial effects on glucose metabolism, appetite and satiety. The effects of the consumption of both sweeteners on uric acid require further study to demonstrate their clinic significance.

Calorie Restriction Mimetics: Upstream-Type Compounds for Modulating Glucose Metabolism.

Calorie restriction (CR) can prolong the human lifespan, but enforcing long-term CR is difficult. Therefore, a compound that reproduces the effect of CR without CR is needed. In this review, we summarize the current knowledge on compounds with CR mimetic (CRM) effects. More than 10 compounds have been listed as CRMs, some of which are conventionally categorized as upstream-type CRMs showing glycolytic inhibition, while the others are categorized as downstream-type CRMs that regulate or genetically modulate intracellular signaling proteins. Among these, we focus on upstream-type CRMs and propose their classification as compounds with energy metabolism inhibition effects, particularly glucose metabolism modulation effects. The upstream-type CRMs reviewed include chitosan, acarbose, sodium-glucose cotransporter 2 inhibitors, and hexose analogs such as 2-deoxy-d-glucose, d-glucosamine, and d-allulose, which show antiaging and longevity effects. Finally, we discuss the molecular definition of upstream-type CRMs.