Effects of nonnutritive sugar inclusion in laboratory diets and attracticidal spheres on survivorship and mobility of 2 Dipteran species, Rhagoletis pomonella (Diptera: Tephritidae) and Drosophila suzukii (Diptera: Drosophilidae)

Native apple maggot fly, Rhagoletis pomonella, and invasive spotted-wing drosophila, Drosophila suzukii, are key pests of apple and small fruit, respectively, in the United States. Both species are typically managed with standard insecticide applications. However, interest in alternative strategies that result in insecticide reductions has led to evaluations of nonnutritive sugars as toxicants for Drosophila species and development of attracticidal spheres for both species. Here, we evaluated the survivorship of R. pomonella and D. suzukii when provided with standard diets that substituted saccharin, sucralose, aspartame, erythritol, dextrose, or mannitol for the sucrose component and compared them with standard diets and water-only controls for up to 15 days. Presence of erythritol and mannitol significantly decreased survivorship of R. pomonella and erythritol significantly decreased the survivorship of D. suzukii. However, mobility trials following a 2 h exposure to aqueous solutions of each sugar treatment resulted in no strong impact on either species. Survivorship after 30 min exposure to erythritol or mannitol alone, or in combination with varying concentrations of sucrose (serving as a phagostimulant) at 30 min and 24 h were evaluated for both species. Only D. suzukii survivorship was affected with decreased survivorship on erythritol:sucrose solutions of 20:0% and 15:5% for 24 h. Based on all results, erythritol appeared most promising, and was integrated into attracticidal spheres as a toxicant but even at the highest concentration, survivorship remained unaffected for either species, thus making this nonnutritive sugar impractical and ineffective as a toxicant substitute in attracticidal spheres.

Comparative Transcriptomic Analysis Revealing the Potential Mechanisms of Erythritol-Caused Mortality and Oviposition Inhibition in Drosophila melanogaster

Erythritol has shown excellent insecticidal performance against a wide range of insect species, but the molecular mechanism by which it causes insect mortality and sterility is not fully understood. The mortality and sterility of Drosophila melanogaster were assessed after feeding with 1M erythritol for 72 h and 96 h, and gene expression profiles were further compared through RNA sequencing. Enrichment analysis of GO and KEGG revealed that expressions of the adipokinetic hormone gene (Akh), amylase gene (Amyrel), α-glucosidase gene (Mal-B1/2, Mal-A1-4, Mal-A7/8), and triglyceride lipase gene (Bmm) were significantly up-regulated, while insulin-like peptide genes (Dilp2, Dilp3 and Dilp5) were dramatically down-regulated. Seventeen genes associated with eggshell assembly, including Dec-1 (down 315-fold), Vm26Ab (down 2014-fold) and Vm34Ca (down 6034-fold), were significantly down-regulated or even showed no expression. However, there were no significant differences in the expression of three diuretic hormone genes (DH44, DH31, CAPA) and eight aquaporin genes (Drip, Big brain, AQP, Eglp1, Eglp2, Eglp3, Eglp4 and Prip) involved in osmolality regulation (all p value > 0.05). We concluded that erythritol, a competitive inhibitor of α-glucosidase, severely reduced substrates and enzyme binding, inhibiting effective carbohydrate hydrolysis in the midgut and eventually causing death due to energy deprivation. It was clear that Drosophila melanogaster did not die from the osmolality of the hemolymph. Our findings elucidate the molecular mechanism underlying the mortality and sterility in Drosophila melanogaster induced by erythritol feeding. It also provides an important theoretical basis for the application of erythritol as an environmentally friendly pesticide.

Diuresis and α-glucosidase inhibition by erythritol in Aedes aegypti (Diptera: Culicidae) and viability for efficacy against mosquitoes

BACKGROUND

Sugar alcohols, such as erythritol, are low-impact candidates for attractive toxic sugar baits (ATSB) to kill mosquitoes. To determine whether erythritol has a viable future in ATSB formulations, a suite of assays was conducted to diagnose toxicity mechanisms and starvation effects on mortality in Aedes aegypti (L.) as a model system.

METHODS

We measured general carbohydrate load, glucosidase levels, and free glucose in intoxicated adult mosquitoes to observe whether sugar digestion was impaired. We assayed the effects of sugar combinations with erythritol on larvae and adults. To measure erythritol effects when mosquitoes were not resource-deprived, additional assays manipulated the prior starvation status.

RESULTS

Up to 50,000 ppm of erythritol in water had no effect on larvae within 72 h, but an ammonia spike indicated diuresis in larvae as early as 4 h (F8,44 = 22.50, P < 0.0001) after sucrose/erythritol combinations were added. Adult consumption of erythritol was diuretic regardless of the sugar pairing, while sucrose and erythritol together generated above 80% mortality (F2,273 = 33.30, P < 0.0001) alongside triple the normal excretion (F5,78 = 26.80, P < 0.0004). Glucose and fructose paired individually with erythritol had less mortality, but still double the fecal excretion. When ingesting erythritol-laced meals, less sugar was detected in mosquitoes as compared to after sucrose meals (χ2 = 12.54, df = 1, P = 0.0004).

CONCLUSIONS

Data showed that erythritol is a linear competitive inhibitor of α-glucosidase, marking it as a novel class of insecticide in the current research climate. However, the efficacy on larvae was null and not persistent in adult mosquitoes when compared across various starvation levels. Despite significant diuresis, the combined effects from erythritol are not acute enough for vector control programs considering ATSB against mosquitoes.

Erythritol Can Inhibit the Expression of Senescence Molecules in Mouse Gingival Tissues and Human Gingival Fibroblasts

Oral aging causes conditions including periodontal disease. We investigated how the sugar alcohol erythritol, which has anti-caries effects, impacts aging periodontal tissues and gingival fibroblasts in mice and humans in vivo and in vitro. Mice were classified into three groups: control groups of six-week-old (YC) and eighteen-month-old mice (AC) and a group receiving 5% w/w erythritol water for 6 months (AE). After rearing, RNA was extracted from the gingiva, and the levels of aging-related molecules were measured using PCR. Immunostaining was performed for the aging markers p21, γH2AX, and NF-κB p65. p16, p21, γH2AX, IL-1β, and TNFα mRNA expression levels were higher in the gingiva of the AC group than in the YC group, while this enhanced expression was significantly suppressed in AE gingiva. NF-κB p65 expression was high in the AC group but was strongly suppressed in the AE group. We induced senescence in cultured human gingival fibroblasts using H2O2 and lipopolysaccharide before erythritol treatment, which reduced elevated senescence-related marker (p16, p21, SA-β-gal, IL-1β, and TNFα) expression levels. Knockdown of PFK or PGAM promoted p16 and p21 mRNA expression, but erythritol subsequently rescued pyruvate production. Overall, intraoral erythritol administration may prevent age-related oral mucosal diseases.

Elevated Erythritol: A Marker of Metabolic Dysregulation or Contributor to the Pathogenesis of Cardiometabolic Disease?

Erythritol is a non-nutritive sugar replacement that can be endogenously produced by humans. Witkowski et al. reported that elevated circulating erythritol is associated with adverse cardiovascular events in three independent cohorts, demonstrated in vitro and ex vivo that erythritol promotes platelet activation, and showed faster clotting time in mice injected with erythritol. It was concluded that erythritol fosters enhanced thrombosis. This narrative review presents additional evidence that needs to be considered when evaluating these data and conclusions. We conducted a search of all studies related to erythritol exposure with focus on those that reported vascular health outcomes. Patients with chronically elevated erythritol levels due to inborn errors of metabolism do not exhibit higher platelet activation or thrombosis risk. Most long-term studies in which animals consumed high levels of erythritol do not support its role in platelet activation and thrombosis formation. Clinical data on the effects of chronic intake of erythritol are limited. Erythritol may be merely a marker of dysregulation in the Pentose Phosphate Pathway caused by impaired glycemia. However, this suggestion and the findings of Witkowski et al. need to be further examined. Clinical trials examining the long-term effects of erythritol consumption on cardiometabolic outcomes are required to test the causality between dietary erythritol and cardiometabolic risk. Until supportive data from these trials are available, it cannot be concluded that dietary erythritol promotes platelet activation, thrombosis, and cardiometabolic risk.

Erythritol alters gene transcriptome signatures, cell growth, and biofilm formation in Staphylococcus pseudintermedius

BACKGROUND

Erythritol was found to inhibit the growth of microorganisms. The present study aimed to demonstrate the growth inhibition of Staphylococcus pseudintermedius by erythritol and to define the changes in gene transcription signatures induced by erythritol. Changes in the gene transcription profiles were analysed by RNA sequencing and quantitative reverse transcription PCR. Gene ontology analysis was performed to assign functional descriptions to the genes.

RESULTS

Erythritol inhibited S. pseudintermedius growth in a dose-dependent manner. We then performed a transcriptome analysis of S. pseudintermedius with and without 5% (w/w) erythritol exposure to validate the mechanism of growth inhibition. We revealed that erythritol induced up-regulation of three genes (ptsG, ppdK, and ppdkR) that are related to the phosphoenolpyruvate-dependent sugar phosphotransferase system (PTS). Glucose supplementation restored the up-regulation of the PTS-related genes in response to erythritol. In addition, erythritol down-regulated eleven genes that are located in a single pur-operon and inhibited biofilm formation of S. pseudintermedius.

CONCLUSIONS

These findings indicated that erythritol antagonistically inhibits PTS-mediated glucose uptake, thereby exerting a growth inhibitory effect on S. pseudintermedius. Moreover, erythritol inhibits the 'de novo' IMP biosynthetic pathway that may contribute to biofilm synthesis in S. pseudintermedius.

Evaluation of Solutions Containing Fluoride, Sodium Trimetaphosphate, Xylitol, and Erythritol, Alone or in Different Associations, on Dual-Species Biofilms

Although the association of polyols/polyphosphates/fluoride has been demonstrated to promote remarkable effects on dental enamel, little is known on their combined effects on biofilms. This study assessed the effects of solutions containing fluoride/sodium trimetaphosphate (TMP)/xylitol/erythritol on dual-species biofilms of Streptococcus mutans and Candida albicans. Biofilms were grown in the continuous presence of these actives alone or in different associations. Quantification of viable plate counts, metabolic activity, biofilm biomass, and extracellular matrix components were evaluated. Overall, fluoride and TMP were the main actives that significantly influenced most of the variables analyzed, with a synergistic effect between them for S. mutans CFUs, biofilm biomass, and protein content of the extracellular matrix (p < 0.05). A similar trend was observed for biofilm metabolic activity and carbohydrate concentrations of the extracellular matrix, although without statistical significance. Regarding the polyols, despite their modest effects on most of the parameters analyzed when administered alone, their co-administration with fluoride and TMP led to a greater reduction in S. mutans CFUs and biofilm biomass compared with fluoride alone at the same concentration. It can be concluded that fluoride and TMP act synergistically on important biofilm parameters, and their co-administration with xylitol/erythritol significantly impacts S. mutans CFUs and biomass reduction.

The artificial sweetener erythritol and cardiovascular event risk

Artificial sweeteners are widely used sugar substitutes, but little is known about their long-term effects on cardiometabolic disease risks. Here we examined the commonly used sugar substitute erythritol and atherothrombotic disease risk. In initial untargeted metabolomics studies in patients undergoing cardiac risk assessment (n = 1,157; discovery cohort, NCT00590200 ), circulating levels of multiple polyol sweeteners, especially erythritol, were associated with incident (3 year) risk for major adverse cardiovascular events (MACE; includes death or nonfatal myocardial infarction or stroke). Subsequent targeted metabolomics analyses in independent US (n = 2,149, NCT00590200 ) and European (n = 833, DRKS00020915 ) validation cohorts of stable patients undergoing elective cardiac evaluation confirmed this association (fourth versus first quartile adjusted hazard ratio (95% confidence interval), 1.80 (1.18-2.77) and 2.21 (1.20-4.07), respectively). At physiological levels, erythritol enhanced platelet reactivity in vitro and thrombosis formation in vivo. Finally, in a prospective pilot intervention study ( NCT04731363 ), erythritol ingestion in healthy volunteers (n = 8) induced marked and sustained (>2 d) increases in plasma erythritol levels well above thresholds associated with heightened platelet reactivity and thrombosis potential in in vitro and in vivo studies. Our findings reveal that erythritol is both associated with incident MACE risk and fosters enhanced thrombosis. Studies assessing the long-term safety of erythritol are warranted.

Nonnutritive Sugars for Spotted-Wing Drosophila (Diptera: Drosophilidae) Control Have Minimal Nontarget Effects on Honey Bee Larvae, a Pupal Parasitoid, and Yellow Jackets

Drosophila suzukii Matsumura, spotted-wing drosophila, is a major pest of small fruits and cherries and often managed with conventional insecticides. Our previous work found that erythritol, a nonnutritive polyol, has insecticidal properties to D. suzukii. Two formulations of erythritol (1.5M), with 0.5M sucrose or 0.1M sucralose, are most effective at killing D. suzukii. In this study, we investigated the nontarget effects of these erythritol formulations on honey bee Apis mellifera Linnaeus larvae, a pupal parasitoid of D. suzukii, Pachycrepoideus vindemiae Rondani, and western yellow jacket, Vespula pensylvanica Saussure. We directly exposed honey bee larvae by adding a high dose (2 µl) to larval cells and found no significant mortality from either formulation compared to the water control. Pachycrepoideus vindemiae may encounter erythritol in field settings when host plants of D. suzukii are sprayed. The erythritol+sucralose formulation was more detrimental than erythritol+sucrose to P. vindemiae, however, this effect was greatly reduced within a 21-d period when a floral source was present. Since yellow jackets are a nuisance pest and were attracted to the erythritol formulations in recent field trials, we tested adult V. pensylvanica survival with continuous consumption of these formulations in the laboratory. We found no detectable detriment from either formulation, compared to the sucrose control. Overall, both erythritol formulations caused minimal nontarget effects on honey bee larvae, P. vindemiae parasitoids, and western yellow jackets.

Erythritol: An In-Depth Discussion of Its Potential to Be a Beneficial Dietary Component

The sugar alcohol erythritol is a relatively new food ingredient. It is naturally occurring in plants, however, produced commercially by fermentation. It is also produced endogenously via the pentose phosphate pathway (PPP). Consumers perceive erythritol as less healthy than sweeteners extracted from plants, including sucrose. This review evaluates that perspective by summarizing current literature regarding erythritol's safety, production, metabolism, and health effects. Dietary erythritol is 30% less sweet than sucrose, but contains negligible energy. Because it is almost fully absorbed and excreted in urine, it is better tolerated than other sugar alcohols. Evidence shows erythritol has potential as a beneficial replacement for sugar in healthy and diabetic subjects as it exerts no effects on glucose or insulin and induces gut hormone secretions that modulate satiety to promote weight loss. Long-term rodent studies show erythritol consumption lowers body weight or adiposity. However, observational studies indicate positive association between plasma erythritol and obesity and cardiometabolic disease. It is unlikely that dietary erythritol is mediating these associations, rather they reflect dysregulated PPP due to impaired glycemia or glucose-rich diet. However, long-term clinical trials investigating the effects of chronic erythritol consumption on body weight and risk for metabolic diseases are needed. Current evidence suggests these studies will document beneficial effects of dietary erythritol compared to caloric sugars and allay consumer misperceptions.

The effect of toothpaste with reduced concentration of fluoride-containing sodium trimetaphosphate and polyols on initial enamel erosion

OBJECTIVES

This in vitro study evaluated the efficacy of toothpaste containing fluoride (F), sodium trimetaphosphate (TMP), and xylitol and erythritol (XE) to inhibit or repair initial enamel erosion lesions.

MATERIALS AND METHODS

Bovine enamel blocks (n = 120) were selected according to surface hardness (SH) and randomly divided into 5 experimental groups (n = 24 blocks/group): Placebo (no F, TMP, XE); 1100 ppm F; 16% xylitol + 4% erythritol (XE); 200 ppm F + 0.2% TMP (200 ppm F/TMP); and 200 ppm F + 0.2% TMP + 16% xylitol + 4% erythritol (200 ppm F/TMP/XE). The sound and softened blocks were immersed in toothpaste slurry in human saliva for 2 min. The blocks were then submitted to 4 erosive challenges in citric acid (0.75%, pH 3.5), each challenge for 1 min, with stirring. The SH of the blocks was determined after treatment (t) and after the 4 erosive challenges. In addition, the precipitates were analyzed by scanning electron microscopy (SEM). Variables were submitted to a two-way repeated-measures analysis of variance followed by a Student-Newman-Keuls test (p < 0.05).

RESULTS

Toothpaste containing 200 ppm F/TMP/XE led to the highest protective and repair effect compared to the other groups (p < 0.001). The protective and repair effect was XE > 200 ppm F/TMP > 1100 ppm F > placebo (p < 0.001). All groups produced precipitates with a thicker layer for XE and TMP groups.

CONCLUSIONS

Toothpaste containing 200 ppm F, TMP, and polyols demonstrated a superior protective and repair effect in initial enamel erosive lesions in vitro.

CLINICAL RELEVANCE

Toothpaste containing F and polyols could be an advantage in patients affected by dental erosion, due to its higher preventive potential, mainly in individuals who frequently drink acidic beverages. However, future studies are needed to confirm these results.

Oral Erythritol Reduces Energy Intake during a Subsequent ad libitum Test Meal: A Randomized, Controlled, Crossover Trial in Healthy Humans

The impact of oral erythritol on subsequent energy intake is unknown. The aim was to assess the effect of oral erythritol compared to sucrose, sucralose, or tap water on energy intake during a subsequent ad libitum test meal and to examine the release of cholecystokinin (CCK) in response to these substances. In this randomized, crossover trial, 20 healthy volunteers received 50 g erythritol, 33.5 g sucrose, or 0.0558 g sucralose dissolved in tap water, or tap water as an oral preload in four different sessions. Fifteen minutes later, a test meal was served and energy intake was assessed. At set time points, blood samples were collected to quantify CCK concentrations. The energy intake (ad libitum test meal) was significantly lower after erythritol compared to sucrose, sucralose, or tap water (p < 0.05). Before the start of the ad libitum test meal, erythritol led to a significant increase in CCK compared to sucrose, sucralose, or tap water (p < 0.001). Oral erythritol given alone induced the release of CCK before the start of the ad libitum test meal and reduced subsequent energy intake compared to sucrose, sucralose, or tap water. These properties make erythritol a useful sugar alternative.

Sugar alcohols have the potential as bee-safe baits for the common wasp

BACKGROUND

Pest insects are often baited with poisoned feeding stimulants, the most common of which are sugars. However, sugars are attractive for most animal species, which makes it difficult to target only a specific pest insect species. Here, we assessed different sugar alcohols for their potential as more species-selective feeding stimulants for pest insects.

RESULTS

We tested the attractiveness of the sugar alcohols sorbitol, xylitol and erythritol with a capillary feeder assay in wasps (as potential pest insects, because introduced wasps are a pest in many regions) and bees (as non-target insects). For the common wasp (Vespula vulgaris), sorbitol and xylitol acted as nutritive feeding stimulants, and erythritol acted as a non-nutritive feeding stimulant. For the buff-tailed bumble bee (Bombus terrestris), sorbitol acted as a feeding stimulant, while for the honey bee (Apis mellifera), none of the sugar alcohols acted as feeding stimulant.

CONCLUSION

The species-specific preferences for sugar alcohols suggest their potential as species-selective insect baits. The wasp-specific preference for xylitol suggests its potential as a bee-safe alternative to sugar-containing bait for controlling the common wasp. © 2022 The Authors. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

The bacteriostatic effect of erythritol on canine periodontal disease-related bacteria

Erythritol helps both prevent and improve periodontal disease and is therefore widely used for dental care in humans. However, only a few studies have investigated the effects of erythritol on periodontal disease in animals. We hypothesized that erythritol could be used to prevent and improve periodontal disease also in canines and investigated the effects of erythritol on canine periodontal disease-related pathogenic bacteria using both in vitro and in vivo methods. The effect of erythritol on the proliferation of Porphyromonas gulae, which is reportedly associated with canine periodontal disease, was investigated in vitro. In addition, a 4-week intervention trial using an external gel preparation containing 5% erythritol was performed in canines with mild periodontal disease; changes in the microbiota around periodontal lesions were investigated using next-generation sequencing and bioinformatics analysis. The growth of P. gulae was significantly suppressed by erythritol in vitro. In the intervention study, the Shannon index, an indicator of the species distribution α-diversity, and the occupancy of several canine periodontal disease - related bacteria ( P. gulae, P. cangingivalis) were significantly decreased in periodontal lesions. Based on the results of in vitro and in vivo studies, we conclude that, as in humans, erythritol has bacteriostatic effects against periodontal disease - related bacteria in canines.

Effect of a Chronic Intake of the Natural Sweeteners Xylitol and Erythritol on Glucose Absorption in Humans with Obesity

In patients with obesity, accelerated nutrients absorption is observed. Xylitol and erythritol are of interest as alternative sweeteners, and it has been shown in rodent models that their acute ingestion reduces intestinal glucose absorption. This study aims to investigate whether a chronic intake of xylitol and erythritol impacts glucose absorption in humans with obesity. Forty-six participants were randomized to take either 8 g of xylitol or 12 g of erythritol three times a day for five to seven weeks, or to be part of the control group (no substance). Before and after the intervention, intestinal glucose absorption was assessed during an oral glucose tolerance test with 3-Ortho-methyl-glucose (3-OMG). The effect of xylitol or erythritol intake on the area under the curve for 3-OMG concentration was not significant. Neither the time (pre or post intervention), nor the group (control, xylitol, or erythritol), nor the time-by-group interaction effects were significant (p = 0.829, p = 0.821, and p = 0.572, respectively). Therefore, our results show that a chronic intake of the natural sweeteners xylitol and erythritol does not affect intestinal glucose absorption in humans with obesity.

Erythritol Ameliorates Small Intestinal Inflammation Induced by High-Fat Diets and Improves Glucose Tolerance

BACKGROUND

Erythritol, a sugar alcohol, is widely used as a substitute for sugar in diets for patients with diabetes or obesity.

METHODS

In this study, we aimed to investigate the effects of erythritol on metabolic disorders induced by a high-fat diet in C57BL/6J mice, while focusing on changes in innate immunity.

RESULTS

Mice that were fed a high-fat diet and administered water containing 5% erythritol (Ery group) had markedly lower body weight, improved glucose tolerance, and markedly higher energy expenditure than the control mice (Ctrl group) (n = 6). Furthermore, compared with the Ctrl group, the Ery group had lesser fat deposition in the liver, smaller adipocytes, and significantly better inflammatory findings in the small intestine. The concentrations of short-chain fatty acids (SCFAs), such as acetic acid, propanoic acid, and butanoic acid, in the serum, feces, and white adipose tissue of the Ery group were markedly higher than those in the Ctrl group. In flow cytometry experiments, group 3 innate lymphoid cell (ILC3) counts in the lamina propria of the small intestine and ILC2 counts in the white adipose tissue of the Ery group were markedly higher than those in the Ctrl group. Quantitative real-time reverse transcription polymerase chain reaction analyses showed that the Il-22 expression in the small intestine of the Ery group was markedly higher than that in the Ctrl group.

CONCLUSIONS

Erythritol markedly decreased metabolic disorders such as diet-induced obesity, glucose intolerance, dyslipidemia, and fat accumulation in the mouse liver by increasing SCFAs and modulating innate immunity.

Effects of chitosan and erythritol on labellar taste neuron activity, proboscis extension reflex, daily food intake, and mortality of male and female spotted-winged drosophila, Drosophila suzukii

In recent years, there has been interest in reduced-risk materials with insecticidal properties for the invasive pest spotted-wing drosophila, Drosophila suzukii. Here, we compared the peripheral sensitivity (via the tip-recording technique, used to monitor the neural activity of gustatory receptor neurons [GRNs]) and palatability (via the Proboscis Extension Reflex [PER]) of chitosan, a polysaccharide derived from chitin, with that of erythritol, a sugar alcohol, to male and female D. suzukii. Because in some insect species it has previously been shown that chitosan has some insecticidal properties, then treatment effects on mortality rates of male and female D. suzukii were quantified. Physiological recordings from the l-type labellar sensilla showed that erythritol evoked responses from one GRN, while chitosan elicited spiked activity from a second one. The first PER bioassay revealed that the level of response to erythritol increased significantly for males and females as the concentrations increased, and the effect of fly sex was non-significant. The second PER bioassay compared the male and female response to chitosan and erythritol each at 0.125, 0.25, 0.5, 1, and 2% concentrations. The overall female PER to erythritol was significantly greater than that exhibited by males, and no differences were noted between sexes when chitosan was evaluated. These results indicate that chitosan alone can elicit PER responses in adult D. suzukii. In the third experiment, chitosan was toxic to D. suzukii. When combined with sucrose (2%), chitosan elicited high levels (80-100%) of mortality of adult D. suzukii within 3 days, particularly in males. The presence of erythritol did not seem to increase the toxic effect of chitosan.

Impact of Steviol Glycosides and Erythritol on the Human and Cebus apella Gut Microbiome

Leaf extracts of Stevia rebaudiana, composed of more than 10 steviol glycosides (SGs), are used as non-nutritive, table sugar (sucrose) alternatives due to their high level of sweetness and low caloric impact. They are often combined with the sugar alcohol erythritol to increase volume and reduce aftertaste. Little is known of the impact of sugar alternatives on the human gut microbiota in terms of the diversity, composition, and metabolic products. Testing of SGs and erythritol using six representatives of the gut microbiota in vitro found no impact on bacterial growth, yet treatment with erythritol resulted in an enhancement of butyric and pentanoic acid production when tested using a human gut microbial community. Furthermore, administration of SGs and erythritol to a Cebus apella model resulted in changes to the gut microbial structure and diversity. Overall, the study did not find a negative impact of SGs and erythritol on the gut microbial community.

The plastidial metabolite 2-C-methyl-D-erythritol-2,4-cyclodiphosphate modulates defence responses against aphids

Feeding by insect herbivores such as caterpillars and aphids induces plant resistance mechanisms that are mediated by the phytohormones jasmonic acid (JA) and salicylic acid (SA). These phytohormonal pathways often crosstalk. Besides phytohormones, methyl-D-erythriol-2,4-cyclodiphosphate (MEcPP), the penultimate metabolite in the methyl-D-erythritol-4-phosphate pathway, has been speculated to regulate transcription of nuclear genes in response to biotic stressors such as aphids. Here, we show that MEcPP uniquely enhances the SA pathway without attenuating the JA pathway. Arabidopsis mutant plants that accumulate high levels of MEcPP (hds3) are highly resistant to the cabbage aphid (Brevicoryne brassicae), whereas resistance to the large cabbage white caterpillar (Pieris brassicae) remains unaltered. Thus, MEcPP is a distinct signalling molecule that acts beyond phytohormonal crosstalk to induce resistance against the cabbage aphid in Arabidopsis. We dissect the molecular mechanisms of MEcPP mediating plant resistance against the aphid B. brassicae. This shows that MEcPP induces the expression of genes encoding enzymes involved in the biosynthesis of several primary and secondary metabolic pathways contributing to enhanced resistance against this aphid species. A unique ability to regulate multifaceted molecular mechanisms makes MEcPP an attractive target for metabolic engineering in Brassica crop plants to increase resistance to cabbage aphids.

Larvicidal potential of the polyol sweeteners erythritol and xylitol in two filth fly species

The house fly, Musca domestica (L.) (Diptera: Muscidae), and the stable fly, Stomoxys calcitrans (L.) (Diptera: Muscidae), are two filth flies responsible for significant economic losses in animal production. Although some chemical control products target adults of both species, differences in mouthpart morphology and behavior necessitates distinct modalities for each. For these reasons, larvicides are an attractive means of chemical control. We assessed the potential of the polyol sweeteners erythritol and xylitol as larvicides to the house fly and stable fly. LC₅₀ values of erythritol against 2^nd instar larvae were 34.94 mg/g media (house fly) and 22.10 mg/g media (stable fly). For xylitol, LC₅₀ values were 74.91 mg/g media (house fly) and 41.58 mg/g media (stable fly). When given a choice, neither species showed a preference for ovipositing in media treated with either sweetener at various concentrations or in media without sweetener. Significantly lower development from egg to adult was observed when the 2^nd instar LC₅₀ equivalent of each sweetener was present in the media compared to controls. Erythritol and xylitol both have larvicidal qualities, however their effective concentrations would necessitate creative product formulation and deployment methods to control all stages of developing flies.

Effect of erythritol formulation on the mortality, fecundity and physiological excretion in Drosophila suzukii

Previously, we studied various combinations of non-nutritive sugars including erythritol and erythrose having a potentially insecticidal effect on Drosophila suzukii. The study suggested two potential physiological changes causing fly mortality: 1) starvation from the feeding of non-metabolizable erythritol and erythrose; 2) abnormal osmotic pressure increased in the hemolymph with erythritol transported from the midgut. In the present study, sucrose and erythritol were applied to blueberries and effects of these combinations on fly mortality and fecundity were monitored in the lab and greenhouse. In the lab, two sucrose/erythritol formulations (0.5M sucrose/2M erythritol, 1M sucrose/2M erythritol) resulted in the highest mortality and the lowest fecundity among D. suzukii adults. Two formulations, therefore, were selected for further evaluation with blueberry bushes and fruits in the greenhouse; fly survival with 0.5M sucrose/2M erythritol was significantly lower than 1M sucrose/2M erythritol for 7days. Unlike the smaller container, mortality occurred faster in the greenhouse probably because flies moved more in the bigger cage accelerating the exhaustion of energy reserves in the body. We examined presence of erythritol in the hemolymph and frass to determine the nutritional metabolism and absorption of erythritol in D. suzukii. Unlike sucrose, a large amount of erythritol was observed in the hemolymph of the fly that ingested 0.5M sucrose/0.5M erythritol. Erythritol was also found in the frass of the same fly. The results imply that erythritol might be directly transported from the midgut without being metabolized and stored, but is accumulated in the hemolymph which in turn elevates the osmotic pressure in the fly hemolymph. For practical application, the sucrose/erythritol combination would be more effective than erythritol alone because the combination tastes sweeter to elicit more feeding. This erythritol formulation can be a potential insecticide used alone or as a delivery agent combined with conventional or biological insecticides to enhance their efficacy.

Survival of the House Fly (Diptera: Muscidae) on Truvia and Other Sweeteners

The house fly, Musca domestica L. (Diptera: Muscidae), is a disease vector of mechanically transmitted pathogens including bacteria, viruses, and protozoans. Opportunities for pathogen transmission can increase as fly longevity increases. Dietary preferences play an important role in insect longevity; therefore, we investigated house fly preferences, sucrose availability, and caloric constraints on house fly longevity. Experimental goals were: 1) to test the effects of calorie restriction on survival of house flies by manipulating concentrations of erythritol (low caloric content) and sucrose (high caloric content), and comparing commercial sweeteners of differing calorie content, 2) to identify house fly preferences for either erythritol or sucrose, and 3) to evaluate the insecticidal activity or toxicity of erythritol on house flies. Our data show that house flies may prefer high calorie options when given a choice and that house fly longevity likely increases as calorie content increases. Additionally, no significant differences in longevity were observed between the water only control (zero calories) and erythritol treatments. This suggests that decreased survival rates and death could be the result of starvation rather than insecticidal activity. This research furthers our understanding of house fly survival and sugar-feeding behavior.

Identification and characterization of EYK1, a key gene for erythritol catabolism in Yarrowia lipolytica

Erythritol is a four-carbon sugar alcohol synthesized by osmophilic yeasts, such as Yarrowia lipolytica, in response to osmotic stress. This metabolite has application as food additive due to its sweetening properties. Although Y. lipolytica can produce erythritol at a high level from glycerol, it is also able to consume it as carbon source. This ability negatively affects erythritol productivity and represents a serious drawback for the development of an efficient erythritol production process. In this study, we have isolated by insertion mutagenesis a Y. lipolytica mutant unable to grow on erythritol. Genomic characterization of the latter highlighted that the mutant phenotype is directly related to the disruption of the YALI0F01606g gene. Several experimental evidences suggested that the identified gene, renamed EYK1, encodes an erythrulose kinase. The mutant strain showed an enhanced capacity to produce erythritol as compared to the wild-type strain. Moreover, in specific experimental conditions, it is also able to convert erythritol to erythrulose, another compound of biotechnological interest.

Effect of non-nutritive sugars to decrease the survivorship of spotted wing drosophila, Drosophila suzukii

In this study, we investigated the effects of non-nutritive sugars and sugar alcohols on the survivorship of spotted wing drosophila, Drosophila suzukii, and found erythritol and erythrose as potentially insecticidal to the fly. In a dose-dependent study, erythritol and erythrose significantly reduced fly longevity, with 100% mortality with 1, 0.5, 0.1 & 0.05M doses after feeding for 7days. When sucrose and erythritol solutions were provided separately to flies for 7days, there was no effect on survivorship regardless of erythritol concentrations. However, with a serial combination of sucrose and erythritol solutions, fly survivorship was significantly decreased for the same period. Also, the higher dose of erythritol regardless of the sucrose dose combined showed greater mortality. In a no-choice assay, D. suzukii ingested more erythritol than sucrose or water, indicating the fly continuously fed on erythritol for 72h. Also under no-choice conditions, erythritol and sucrose-fed flies gained more weight than water-fed flies. However, in two-choice assays, the amount of erythritol ingested was less than sucrose or water. Total sugar and glycogen levels among erythritol and erythrose-fed flies were significantly less than mannitol, sorbitol, xylitol, and sucrose-fed flies after 48h. This indicates that these two non-nutritive sugars can't be used a substrate for enzymes involved in sugar metabolism. Although the metabolism of erythritol and erythrose is unknown in insects, the mortality of D. suzukii flies ingesting these sugars might be caused by two potential physiological changes. The fly is starved by feeding of non-metabolizable erythritol and erythrose, or experiences abnormally high osmotic pressure in the hemolymph with erythritol molecules diffused from the midgut. Non-nutritive sugars might be used as an insecticide alone or combined with conventional or biological insecticides to enhance efficacy. If other sugar sources are present, a palatable sugar might be mixed with erythritol to elicit feeding.

Erythritol and Lufenuron Detrimentally Alter Age Structure of Wild Drosophila suzukii (Diptera: Drosophilidae) Populations in Blueberry and Blackberry

We report on the efficacy of 0.5 M (61,000 ppm) erythritol (E) in Truvia Baking Blend, 10 ppm lufenuron (L), and their combination (LE) to reduce egg and larval densities of wild populations of Drosophila suzukii (Matsumura) infesting fields of rabbiteye blueberries (Vaccinium virgatum) and blackberries (Rubus sp.). Formulations included the active ingredients (lufenuron, erythritol, or both), sugar (in control and erythritol treatments), and Dawn hand-soap applied to plants with pressurized 3-gallon garden spray tanks. The three chemical treatments (E, L, and LE) had no effect on D. suzukii ovipositing in blackberry and blueberry fruit, but they did reduce larval infestation by 75%, particularly densities of first and second instars. Erythritol and lufenuron were equally efficacious compounds as a D. suzukii ovicide and larvicide, but they did not display additive or synergistic activity. Extremely high larval mortality in control fruits show an age structure heavily skewed toward egg output.

Effect of Sweeteners on the Survival of Solenopsis invicta (Hymenoptera: Formicidae)

The red imported fire ant, Solenopsis invicta Buren, is a serious agricultural, ecological, and public health pest in its invaded range. Chemical insecticides have been widely used for the prevention and control of this notorious pest. To search for novel, cost-effective, and environmentally friendly materials for fire ant control, we tested various sweeteners for their toxicity to S. invicta. The S. invicta that were fed erythritol, aspartame, and saccharin exhibited significantly higher mortality rates than those fed other sweeteners. After 72 h, the mortality of the workers that were fed 0.1 or 0.2 g/ml erythritol was above 80%. For males, females, and larvae, mortality was close to 100% after 9 d at high concentrations. Dose-dependent effects of erythritol were observed for workers, males, females, and larvae at the concentrations tested. Rapid transfer of toxicity among the fire ant colony was also observed. Our results suggest that erythritol can be developed as an additive ingredient in baits.

[Effect of Lactobacillus acidophilus on metabolizing lactic acid in formula milk: a quantitative analysis of the effect of erythritol]

OBJECTIVE

To evaluate the lactic acid productivity of Lactobacillus acidophilus (La) exposed to formula milk containing different concentration of erythritol.

METHODS

La was cultured under anaerobic condition (80% N(2), 10% CO(2), 10% H(2)) at 37 °C in five experimental groups (formula milk mixed with different concentrations of erythritol). The five experimental groups contained 1%, 2%, 4%, 6%, and 8% erythritol, respectively (groups 1% E-M, 2% E-M, 4% E-M, 6% E-M, 8% E-M). Formula milk served as control group (group M). The lactic acid was analyzed by high performance liquid chromatography (HPLC) at 4 h intervals during 24 h. The peak-area of lactic acid was recorded and used to calculate the concentration of lactic acid through the equation of a standard curve (y = 590 244x + 67 507). ANOVA and Tukey HDS analysis were used to analyze the data.

RESULTS

The concentration of lactic acid at 24 h was group M [(4.693 ± 0.105) g/L], group 1% E-M[(4.114 ± 0.186) g/L], group 2% E-M[(3.720 ± 0.158) g/L], group 4% E-M[(3.045 ± 0.152) g/L], group 6% E-M[(2.971 ± 0.086) g/L], group 8% E-M[(2.789 ± 0.142) g/L]. Statistically significant differences in lactic acid concentrations were found between different time points (P < 0.05) and between different groups (F = 187.448, P < 0.05). Moreover, the concentrations of lactic acid in each experimental group was lower than that in control group (P < 0.05). The difference among groups 4% E-M, 6% E-M, and 8% E-M were not statistically significant (P > 0.05).

CONCLUSIONS

Erythritol showed the inhibition potential against La in metabolizing lactic acid in formula milk. The effect of erythritol was concentration depended. The higher concentration of erythritol contained in the milk, the better the inhibition potential against La in metabolizing lactic acid.

Multi-targeted mechanisms underlying the endothelial protective effects of the diabetic-safe sweetener erythritol

Diabetes is characterized by hyperglycemia and development of vascular pathology. Endothelial cell dysfunction is a starting point for pathogenesis of vascular complications in diabetes. We previously showed the polyol erythritol to be a hydroxyl radical scavenger preventing endothelial cell dysfunction onset in diabetic rats. To unravel mechanisms, other than scavenging of radicals, by which erythritol mediates this protective effect, we evaluated effects of erythritol in endothelial cells exposed to normal (7 mM) and high glucose (30 mM) or diabetic stressors (e.g. SIN-1) using targeted and transcriptomic approaches. This study demonstrates that erythritol (i.e. under non-diabetic conditions) has minimal effects on endothelial cells. However, under hyperglycemic conditions erythritol protected endothelial cells against cell death induced by diabetic stressors (i.e. high glucose and peroxynitrite). Also a number of harmful effects caused by high glucose, e.g. increased nitric oxide release, are reversed. Additionally, total transcriptome analysis indicated that biological processes which are differentially regulated due to high glucose are corrected by erythritol. We conclude that erythritol protects endothelial cells during high glucose conditions via effects on multiple targets. Overall, these data indicate a therapeutically important endothelial protective effect of erythritol under hyperglycemic conditions.

Biosurfactant mannosyl-erythritol lipid inhibits secretion of inflammatory mediators from RBL-2H3 cells

BACKGROUND

Biosurfactant mannosyl-erythritol lipids (MELs) are glycolipids produced by microbes that have various biological activities. It has been reported that MELs exhibit excellent surface-activity and also various bioactivities, such as induction of cell differentiation and apoptosis. However, little is known about their action related to drug discovery or drug seeds.

METHODS

We investigated the effects of MELs on the secretion of inflammatory mediators from mast cells that play a central role in allergic responses. Mast cells secrete three kinds of inflammatory mediators and we quantified these secreted mediators by photometer or ELISA. The action mechanisms of MELs were studied by Ca(2+)-sensitive fluorescence dye and Western blotting of phosphorylated proteins.

RESULTS

MELs inhibited exocytotic release by antigen stimulation in a dose-dependent manner. We also found that MELs inhibited antigen-induced secretion of leukotriene C(4) and cytokine TNF-α (tumor necrosis factor-α). The inhibitory action of MELs on mediator secretion was mediated by inhibition of Ca(2+) increase, phosphorylation of MAP kinases and SNARE (soluble N-ethylmaleimide-sensitive factor attachment protein receptor) that serve as a molecular machinery for exocytotic membrane fusion.

CONCLUSIONS

MELs have anti-inflammatory action inhibiting the secretion of inflammatory mediators from mast cells.

GENERAL SIGNIFICANCE

MELs affects two of major intracellular signaling pathways including Ca(2+) increase and MAP kinases. MELs also inhibited the phosphorylation of SNARE proteins that is crucial for not only exocytosis but also intracellular vesicular trafficking.

[Screening of potential antibiotics, inhibitors of the nonmevalonate pathway of isoprenoid biosynthesis--2-C-methyl-D-erythritol-2,4-cyclodiphosphate derivatives]

The recently discovered nonmevalonate pathway of isoprenoid biosynthesis is a prospective target in screening of new antibiotics. Because of the absence of the pathway in the animal cells, the specific inhibitors of the pathway will be a new class of antibiotics against many pathogens (which cause, e.g., malaria, tuberculosis, etc), combining high efficiency and low toxicity. Several derivatives of 2-C-methyl-D-erythritol-2,4-cyclodiphosphate (MEC) were synthesized. 4-Phospho-methyl-D-erythritol-1,2-cyclophosphate, benzyl ether and benzyliden derivative of MEC inhibited the 14C-MEC incorporation into isoprenoids of chromoplasts from red pepper with IC50 of 1.7-5 MM. Some inhibition (about 10%) was also observed with the use of dimethyl ether and isopropyliden derivative of MEC.

Not all mitochondrial carrier proteins support permeability transition pore formation: no involvement of uncoupling protein 1

The mPTP (mitochondrial permeability transition pore) is a non-specific channel that is formed in the mitochondrial inner membrane in response to several stimuli, including elevated levels of matrix calcium. The pore is proposed to be composed of the ANT (adenine nucleotide translocase), voltage-dependent anion channel and cyclophilin D. Knockout studies, however, have demonstrated that ANT is not essential for permeability transition, which has led to the proposal that other members of the mitochondrial carrier protein family may be able to play a similar function to ANT in pore formation. To investigate this possibility, we have studied the permeability transition properties of BAT (brown adipose tissue) mitochondria in which levels of the mitochondrial carrier protein, UCP1 (uncoupling protein 1), can exceed those of ANT. Using an improved spectroscopic assay, we have quantified mPTP formation in de-energized mitochondria from wild-type and Ucp1KO (Ucp1-knockout) mice and assessed the dependence of pore formation on UCP1. When correctly normalized for differences in mitochondrial morphology, we find that calcium-induced mPTP activity is the same in both types of mitochondria, with similar sensitivity to GDP (approximately 50% inhibited), although the portion sensitive to cyclosporin A is higher in mitochondria lacking UCP1 (approximately 80% inhibited, compared with approximately 60% in mitochondria containing UCP1). We conclude that UCP1 is not a component of the cyclosporin A-sensitive mPTP in BAT and that playing a role in mPTP formation is not a general characteristic of the mitochondrial carrier protein family but is, more likely, restricted to specific members including ANT.

[2-(14)C-Methylerythritol 2,4-cyclodiphosphate incorporation into bacterial and plant isoprenoids]

To work out a test system for studying the inhibition of isoprenoid biosynthesis through non-mevalonate pathway, the conversion of 2-(14)C-methylerythritol 2,4-cyclodiphosphate (14C-MEC) into isoprenoids of three bacteria species and into plastids of 11 higher plant species was studied. The highest efficiency (up to 63%) of the process was observed with chromoplasts from narcissus (Narcissus pseudonarcissus L.) and celandine (Chelidonium majus L.). Twenty five percent of added 14C-MEC was recovered in an isoprenoid fraction of red pepper (Capsicum annuum L.) chromoplasts. Thus, these three models can be used to test antibiotic inhibitors of isoprenoid biosynthesis.

Biofilm formation by a biotechnologically important tropical marine yeast isolate, Yarrowia lipolytica NCIM 3589

Biofilm formation by Yarrowia lipolytica, a biotechnologically important fungus in microtitre plates, on glass slide surfaces and in flow cell was investigated. In microtitre plates, there was a short lag phase of adhesion followed by a period of rapid biofilm growth. The fungus formed extensive biofilms on glass slides, whereas in flow-cells a multicellular, three-dimensional microcolony structure was observed. The isolate formed biofilms in seawater and in fresh water media at neutral pH when grown in microtitre plates. The carbon sources differentially affected formation of biofilms in microtitre plates. Lactic acid, erythritol, glycerol, glucose and edible oils supported the formation of biofilms, while alkanes resulted in sub-optimal biofilm development. A variation in the morphology of the fungus was observed with different carbon sources. The results point to the possible existence of highly structured biofilms in varied ecological niches from where the yeast is isolated.

Synthesis and analysis of a fluorinated product analogue as an inhibitor for 1-deoxy-D-xylulose 5-phosphate reductoisomerase

1-deoxy-D-xylulose 5-phosphate (DXP) reductoisomerase (DXR) is an NADPH-dependent enzyme catalyzing the rearrangement and reduction of DXP to methyl-D-erythritol 4-phosphate (MEP). Two mechanisms for this enzymatic reaction have been proposed, involving either an alpha-ketol rearrangement or a retroaldol/aldol rearrangement. In this study, a fluorinated product analogue, FCH(2)-MEP, was synthesized as a possible mechanism-based inactivator for DXR if the retroaldol/aldol mechanism is operative. FCH(2)-MEP was found to be a weak competitive inhibitor, and thus was unable to discriminate between the mechanisms. This result is due to the inability of the targeted enzyme, DXR, to oxidize FCH(2)-MEP to the aldehyde intermediate that is common to both mechanisms. While FCH(2)-MEP failed to act as a mechanism-based inactivator, the insight gained from this study will assist in the future design of inhibitors of DXR.

An HIV RNase H inhibitory 1,3,4,5-tetragalloylapiitol from the African plant Hylodendron gabunensis

A new compound, 1,3,4,5-tetragalloylapiitol ( 1), was isolated from the aqueous extract of the plant Hylodendron gabunensis and was found to be a potent inhibitor of RNase H enzymatic activity. The structure of 1 was elucidated by NMR analyses to be an apiitol ( 2) sugar moiety substituted with four gallic acid residues. Optical rotation measurements of the free sugar following basic hydrolysis indicated that the 3 S absolute configuration was the same as that of d-apiitol. Compound 1 inhibited HIV-1, HIV-2, and human RNase H with IC 50 values of 0.24, 0.13, and 1.5 microM, respectively, but it did not show inhibition of E. coli RNase H at 10 microM.

Sucrose, xylitol, and erythritol increase PMMA permeability for depot antibiotics

Release of antibiotics from antibiotic-loaded PMMA is dependent on its permeability. Loading PMMA with soluble particulate filler has been proposed to increase permeability and antibiotic release for beads and spacers. We therefore assessed particulate sucrose, xylitol, and erythritol as fillers to increase the permeability and elution kinetics of filler-loaded PMMA. Based on lower solubility, we hypothesized that erythritol would not enhance permeability and elution as much as xylitol and sucrose. We made filler-loaded PMMA beads with each of the three fillers combined with phenolphthalein, and soaked in 0.1% NaOH solution. Permeability was assessed qualitatively by relative depth of phenolphthalein color change caused by penetration of NaOH solution into subsequently split beads. Elution was quantitatively assessed by spectrophotometric light absorption measurements of the eluent. Fluid penetration reached the center of 7-mm beads by day 15, similar for all three materials. Elution of phenolphthalein was greater for xylitol than for the other two materials. Particulate sucrose, xylitol, and erythritol fillers increase PMMA permeability and elution kinetics but relative solubility did not determine the relative degree of enhancement of permeability and elution by these materials.

K+-independent initiation of motility in chum salmon sperm treated with an organic alcohol, glycerol

Sperm of salmonid fishes are quiescent in the presence of millimolar concentrations of extracellular K+, but motility initiation occurs when sperm are suspended in K+-free medium. In this study, glycerol (CH2OHCHOHCH2OH) treatment of intact sperm in the presence of K+ induced the initiation of motility even though a large amount of K+ was present. Another organic alcohol, erythritol (CH2OH(CHOH)2CH2OH), had a similar effect, but ethylene glycol (CH2OHCH2OH) did not initiate sperm motility. Furthermore, this glycerol-treated sperm showed motility without subsequent addition of ATP and cAMP. CCCP, an uncoupler of the mitochondrial electron-transport chain involved in ATP synthesis, suppressed motility of glycerol-treated sperm, suggesting that ATP synthesis is required for dynein to slide microtubules in glycerol-treated sperm. The amount of intracellular cAMP ([cAMP]i) in glycerol-treated sperm did not increase on motility activation, but a protein kinase A (PKA) inhibitor, H-89, inhibited glycerol-treated sperm motility. In addition, phosphorylation of protein associated with motility initiation also occurred in glycerol-treated sperm, suggesting that the glycerol treatment induces activation of PKA without an increase in [cAMP]i. Taken together, it can be concluded that organic alcohol, glycerol and erythritol induce phosphorylation for motility initiation, bypassing the increase in [cAMP]i as a result of a decrease in extracellular K+ concentration.

Sugar and alcohol molecules provide a therapeutic strategy for the serpinopathies that cause dementia and cirrhosis

Mutations in neuroserpin and alpha1-antitrypsin cause these proteins to form ordered polymers that are retained within the endoplasmic reticulum of neurones and hepatocytes, respectively. The resulting inclusions underlie the dementia familial encephalopathy with neuroserpin inclusion bodies (FENIB) and Z alpha1-antitrypsin-associated cirrhosis. Polymers form by a sequential linkage between the reactive centre loop of one molecule and beta-sheet A of another, and strategies that block polymer formation are likely to be successful in treating the associated disease. We show here that glycerol, the sugar alcohol erythritol, the disaccharide trehalose and its breakdown product glucose reduce the rate of polymerization of wild-type neuroserpin and the Ser49Pro mutant that causes dementia. They also attenuate the polymerization of the Z variant of alpha1-antitrypsin. The effect on polymerization was apparent even when these agents had been removed from the buffer. None of these agents had any detectable effect on the structure or inhibitory activity of neuroserpin or alpha1-antitrypsin. These data demonstrate that sugar and alcohol molecules can reduce the polymerization of serpin mutants that cause disease, possibly by binding to and stabilizing beta-sheet A.

Glyco- and peptidomimetics from three-component Joullié-Ugi coupling show selective antiviral activity

Chlorination-elimination chemistry coupled with three-component Joullié-Ugi reaction and facile deprotection allowed efficient access to an array of polyhydroxylated pyrrolidines through parallel synthesis that may be considered to be a library of imino (aza) sugars (glycomimetics) and/or dihydroxyprolyl peptides (peptidomimetics). The utility of generating such a library was illustrated by screening against 15 different targets that revealed potent and selective inhibition of the Gaucher's disease glycosyltransferase enzyme glucosylceramide synthase and of primary pathogen model for human hepatitis C virus (HCV) and bovine diarrhoeal virus (BVDV). An observed selectivity for this HCV model over hepatitis B virus and remarkably low toxicity suggest a novel mode of action.

[Properties of 2-C-methyl-D-erythritol 2,4-cyclopyrophosphate--an intermediate in the non-mevalonate isoprenoid biosynthesis]

Extraction and purification from the biomass of Corynebacterium ammoniagenes of 2-C-methyl-D-erhythritol 2,4-cyclopyrophosphate (MEC) was associated with its spontaneous transformation into a number of derivatives (which was due to pyrophosphate bond lability and the formation of complexes with metals). These derivatives included 1,2-cyclophospho-4-phosphate, 2,4-diphosphate, 2,3-cyclophosphate, 1,4-diphosphate, and 3,5-diphosphate (identified by 1H, 31P, and 13C NMR spectroscopy) and accounted for about 10% MEC. When added to a solution of DNA in the presence of the Fenton reagent, MEC prevented DNA decomposition. In addition, MEC slowed down the interaction of the reagent with tempol radicals, which indicates that complexation of ferrous ions by MEC attenuates their ability to catalyze the formation of hydroxyl radicals from hydrogen peroxide. In the presence of 0.23 mM MEC, the rate of respiration of rat liver mitochondria increased 1.8 times. At 0.1-1.0 mM, MEC activated in vitro proliferation of human Vgamma9 T-cells. It is suggested that MEC acts as an endogenous stabilizing agent for bacterial cells subjected to oxidative stress and as an immunomodulator for eukaryotic hosts.

Production of the siderophore 2,3-dihydroxybenzoic acid is required for wild-type growth of Brucella abortus in the presence of erythritol under low-iron conditions in vitro

Production of the siderophore 2,3-dihyroxybenzoic acid (2,3-DHBA) is required for the wild-type virulence of Brucella abortus in cattle. A possible explanation for this requirement was uncovered when it was determined that a B. abortus dhbC mutant (BHB1) defective in 2,3-DHBA production displays marked growth restriction in comparison to its parent strain, B. abortus 2308, when cultured in the presence of erythritol under low-iron conditions. This phenotype is not displayed when these strains are cultured under low-iron conditions in the presence of other readily utilizable carbon and energy sources. The addition of either exogenous 2,3-DHBA or FeCl(3) relieves this growth defect, suggesting that the inability of the B. abortus dhbC mutant to display wild-type growth in the presence of erythritol under iron-limiting conditions is due to a defect in iron acquisition. Restoring 2,3-DHBA production to the B. abortus dhbC mutant by genetic complementation abolished the erythritol-specific growth defect exhibited by this strain in low-iron medium, verifying the relationship between 2,3-DHBA production and efficient growth in the presence of erythritol under low-iron conditions. The positive correlation between 2,3-DHBA production and growth in the presence of erythritol was further substantiated by the observation that the addition of erythritol to low-iron cultures of B. abortus 2308 stimulated the production of 2,3-DHBA by increasing the transcription of the dhbCEBA operon. Correspondingly, the level of exogenous iron needed to repress dhbCEBA expression in B. abortus 2308 was also greater when this strain was cultured in the presence of erythritol than that required when it was cultured in the presence of any of the other readily utilizable carbon and energy sources tested. The tissues of the bovine reproductive tract are rich in erythritol during the latter stages of pregnancy, and the ability to metabolize erythritol is thought to be important to the virulence of B. abortus in pregnant ruminants. Consequently, the experimental findings presented here offer a plausible explanation for the attenuation of the B. abortus 2,3-DHBA-deficient mutant BHB1 in pregnant ruminants.

Liquid formulation of the biocontrol agent Candida sake by modifying water activity or adding protectants

AIMS

To evaluate the effect of modification of water activity (aw) and the addition of protective substances in the preservation medium of liquid formulations of the biocontrol agent Candida sake stored at 4 and 20 degrees C.

METHODS AND RESULTS

The aw of the preservation medium of C. sake was modified from 0.72 to 0.95 by adding glycerol or polyethylene glycol (PEG). Moreover, several protectant substances at different concentrations were evaluated. Modification of lower aw-levels (0.721-0.901) with glycerol did not maintain the viability of the yeast cells. Higher aw-levels (0.93-0.95) with either glycerol or PEG improved the viability but not at acceptable viability levels. C. sake cells maintained viabilities >60% when sugars, such as trehalose, and polyols, such as glycerol and PEG were used as protectants in liquid formulations. Moreover, liquid formulations of C. sake stored at 4 degrees C showed higher number of viable counts than at 20 degrees C. When different sugars were tested, all of them, except 10% fructose, resulted in a viability higher than 50% of the C. sake formulations. Biocontrol of liquid formulation treatments was similar to fresh cells in controlling Penicillium expansum on wounded apples.

CONCLUSIONS

Sugars such as lactose and trehalose could be considered as good protectants in order to obtain liquid formulations of C. sake cells as they maintain the viability >70% for 4 months at 4 degrees C.

SIGNIFICANCE AND IMPACT OF STUDY

This study shows that a suitable liquid formulation for commercial application can be produced with high viability and conservation of biocontrol efficacy. Moreover, if 10% lactose is the protectant used in the formulation, the economic costs would not be limiting for industrial production.

Functional expression and characterization of EryA, the erythritol kinase of Brucella abortus, and enzymatic synthesis of L-erythritol-4-phosphate

The eryA gene of the bacterial pathogen Brucella abortus has been functionally expressed in Escherichia coli. The resultant EryA was shown to catalyze the ATP-dependent conversion of erythritol to L-erythritol-4-phosphate (L-E4P). The steady state kinetic parameters of this reaction were determined and the enzyme was used to prepare L-E4P which was shown to be a weak inhibitor of 2-C-methyl-D-erythritol-4-phosphate cytidyltransferase (YgbP).

[Effect of erithriol on intestinal microflora and morphology of rat internal organs]

In experiences on rats is shown, that 22 daily upkeeping of animals on a diet including eritrit in a dose 1 g/weight of a body, do not cause any changes from the party intestinal microflora and morphological structure of internal bodies. However, the specified doze eritrit causes statistically authentic increase of levels conditionally-pathogenic anaerobius of the representatives microflora, first of all staphylococcus and citratessimilation enterobacteria.

Erythritol attenuates the diabetic oxidative stress through modulating glucose metabolism and lipid peroxidation in streptozotocin-induced diabetic rats

We investigated the effects of erythritol on rats with streptozotocin- (STZ-) induced diabetes mellitus. Oral administration of erythritol [100, 200, or 400 mg (kg body weight)(-1) day(-1) for 10 days] to rats with STZ-induced diabetes resulted in significant decreases in the glucose levels of serum, liver, and kidney. Erythritol also reduced the elevated serum 5-hydroxymethylfurfural level that is glycosylated with protein as an indicator of oxidative stress. In addition, thiobarbituric acid-reactive substance levels of serum and liver and kidney mitochondria were dose-dependently lower in the erythritol-treated groups than in the control diabetic group. Furthermore, the serum creatinine level was reduced by oral administration of erythritol in a dose-dependent manner. These results suggest that erythritol affects glucose metabolism and reduces lipid peroxidation, thereby improving the damage caused by oxidative stress involved in the pathogenesis of diabetes.

[Immunomodulatory properties of 2-C-methyl-D-erythritol-2,4-cyclopyrophosphate and search for its new derivatives]

A strong immunomodulatory effect of 2-C-methyl-D-erythritol-2,4-cyclopyrophosphate (MEC) responsible for the survival of bacteria was shown on isolated macrophages and in experimental infections in mice (typhoid and tularemia). Derivatives of MEC were found by 1H-NMR spectroscopy under stress conditions in colorless mutants of the bacteria and isolated to be subsequently purified and used for modulation of the immune system of animals.

Mannosylerythritol lipid induces characteristics of neuronal differentiation in PC12 cells through an ERK-related signal cascade

Rat pheochromocytoma PC12 cells undergo neuronal differentiation in response to nerve growth factor (NGF). The differentiation involves protein kinase cascades that include the kinases MEK and ERK, as well as activation of the transcription factors c-Jun and c-Fos. We show here, that exposure of PC12 cells to mannosylerythritol lipid (MEL), a yeast extracellular glycolipid, enhances the activity of acetylcholinesterase and interrupts the cell cycle at the G1 phase, with resulting outgrowth of neurites and partial cellular differentiation. Treatment with MEL stimulates the phosphorylation of ERK to a similar extent as treatment with NGF, although, the appearance of phosphorylated ERK is somewhat delayed. Both the MEL-induced outgrowth of neurites and the increase in the activity of acetylcholinesterase are prevented by PD98059, a specific inhibitor of MEK. Northern blotting analysis of c-jun transcripts and analysis of transcription in PC12 cells of a c-jun/CAT reporter construct demonstrated a significant increase in the rate of transcription of the c-jun gene upon treatment with MEL. The sequence elements required for the MEL-mediated activation of transcription of the c-jun gene are located between nucleotides -126 and -79 in the 5' flanking region. Our results suggest that MEL induces characteristics of neuronal differentiation in PC12 cells, with transactivation of the c-jun gene, via an ERK-related signal cascade that is partially overlapping the pathways activated in response to NGF. These results might provide the groundwork for the use of microbial extracellular glycolipids as novel reagents for the treatment of cancer cells.

Solvent effects on squid sodium channels are attributable to movements of a flexible protein structure in gating currents and to hydration in a pore

1. Solvent effects on the time course of gating and sodium currents were analysed in squid sodium channels using four non-electrolytes of different size, glycerol, erythritol, glucose and sucrose, to separate effects of viscosity from those of osmolarity and to obtain viscosity and osmolarity parameters that were independent of molecular size. 2. The gating and sodium currents were reversibly slowed in a voltage-independent manner as the non-electrolyte concentration increased. 3. Solvent effects were analysed using a model in which the percentage change in time constant was expressed by an equation involving the viscosity parameter alpha and the osmolarity parameter delta: t/t0 = alpha (eta/eta 0) - 1 + 100 alpha-1)exp(delta delta pi), where eta/eta 0 is solution viscosity and delta pi is increase in osmolarity. Since the solution viscosity was found experimentally to be a function of the solution osmolarity, solvent effects are described by an equation with one independent variable eta/eta 0 or delta pi. 4. Voltage sensor movement, reflected in gating currents, was primarily sensitive to viscosity, as its decay time constant was a function of eta/eta 0, with only a minor sensitivity to osmolarity (delta was 2-3 water molecules). 5. For sodium currents, alpha was equal to that of gating currents but delta was 2-3 times greater, suggesting that the final channel opening was primarily sensitive to osmolarity (delta delta was 5 water molecules). The relative ineffectiveness of the largest non-electrolyte, sucrose, suggested that this osmolarity-sensitive step in channel opening occurred in the narrow pore region. 6. Sodium channel inactivation was primarily sensitive to osmolarity (delta delta was 8-12 water molecules). 7. The observed viscosity dependence of the sodium current activation and inactivation processes was attributable to the viscosity-dependent process accompanying the gating current. 8. This model explains why non-electrolytes slow sodium currents while electrolytes do not. 9. Viscosity effects on gating currents can be explained by a process in which non-electrolytes interact with the flexible hydrophilic parts of sodium channel proteins, but osmolarity effects on the final step need to be explained by a local interaction of several water molecules with fluctuating protein segments in the pore.

The effects of polyols on the thermal stability of calf thymus DNA

The effects on thermal denaturation of calf thymus DNA (ct-DNA) and its conformational changes induced by the presence in solution of different polyols, namely glycerol, i-erytritol, L( -- ) and D( + ) arabitol, D-mannitol, D-sorbitol and myo-inositol, have been investigated by means of differential scanning calorimetry (DSC) and circular dichroism (CD). By increasing the concentration of these additives a decrease in both the denaturation enthalpy (deltadH) and temperature of the maximum of the denaturation peak (Tmax) of DNA is observed. The values of these thermodynamic parameters depend on both the nature and concentration of the solute. The overall destabilization of DNA molecule has been related to the different capability of polyhydric alcohols to interact with the polynucleotide solvation sites replacing water and to the modification of the electrostatic interactions between the polynucleotide and its surrounding atmosphere of counterions. The particular behaviour of L( -- ) arabitol, which showed a much greater destabilizing ability compared to the other polyols, was further investigated and attributed to a direct more effective interaction with the double helix of DNA. CD spectra showed only a slight alteration of DNA-B structure in the presence of all the molecules here studied, except for L( -- ) arabitol where the DNA molecule seems to undergo a meaningful conformational change. The salt concentration dependence of DNA thermal stability in the presence of L( -- ) arabitol indicates a conformational change of polynucleotide towards a more extended conformation.