Enhancing the flavour quality of Laiyang pear wine by screening sorbitol-utilizing yeasts and co-fermentation strategies

This study took a novel approach to address the dual challenges of enhancing the ethanol content and aroma complexity in Laiyang pear wine. It focused on sorbitol as a pivotal element in the strategic selection of yeasts with specific sorbitol-utilization capabilities and their application in co-fermentation strategies. We selected two Saccharomyces cerevisiae strains (coded as Sc1, Sc2), two Metschnikowia pulcherrima (coded as Mp1, Mp2), and one Pichia terricola (coded as Tp) due to their efficacy as starter cultures. Notably, the Sc2 strain, alone or with Mp2, significantly increased the ethanol content (30% and 16%). Mixed Saccharomyces cerevisiae and Pichia terricola fermentation improved the ester profiles and beta-damascenone levels (maximum of 150%), while Metschnikowia pulcherrima addition enriched the phenethyl alcohol content (maximum of 330%), diversifying the aroma. This study investigated the efficacy of strategic yeast selection based on sorbitol utilization and co-fermentation methods in enhancing Laiyang pear wine quality and aroma.

Development and characterization of camel gelatin films: Influence of camel bone age and glycerol or sorbitol on film properties

This study developed and evaluated camel bone gelatin films (CBGFs) with glycerol or sorbitol as plasticizers. Gelatin extracted from the bones of camels (Camelus dromedarius) at ages ranging from 2.5 to 7 years was used. A comprehensive analysis was conducted, evaluating a range of properties including thickness, moisture sorption capacity, water vapor permeability (WVP), infrared spectral characteristics, light absorption behavior, solubility, as well as mechanical and thermal attributes. This thorough examination allowed for a nuanced understanding of the diverse characteristics exhibited by the camel gelatin samples across different age groups. The results indicated that camel age, glycerol, and sorbitol had a significant impact on the properties of the film (P < 0.05). Tensile strength ranged from 0.32 MPa to 3.99 MPa, while the percentage of elongation at break varied from 89.42 % to 2.68 %. Film color (lightness, L) ranged from 21.39 to 41.33. Glycerol and sorbitol plasticized films were 100 % water soluble. Moisture sorption increased with temperature (25 °C, 35 °C, and 45 °C), with sorbitol films retaining less water. WVP was low in films from old camel bones and high in glycerol-plasticized CBGF-2.5Y and CBGF-4.5Y. Thermal analysis showed a melting temperature between 158.60 °C and 174.10 °C, depending on bone age and plasticizer. These films demonstrate promise for use in food packaging, coatings, and pharmaceutical applications.

Development of a thin layer chromatography-based method to detect sorbitol presence in milk and its applicability in formalin preserved milk samples

Sorbitol has been the new and emerging adulterant in dairy industry. The main aim of the study was to develop a method to detect sorbitol in milk, which is not affected by other sugars, polyols and formalin. Hence, a thin layer chromatographic (TLC) method was standardized to detect the sorbitol in milk. In the study 90 s duration for the impregnation of Silica gel 60F TLC plates with Cu- ions was found suitable to resolve sorbitol as a distinct spot. The standardized conditions were (1) developing solvent system consisting of n-propanol: ethyl acetate: water (7:1:2), (2) 0.5% of potassium permanganate in 0.1 M NaOH as color developing reagent. (3) Drying temperature (65°C/ 10 min.) after spraying the color developing reagent. The limit of detection was 0.2% of added sorbitol in milk. The standardized method could also detect the sorbitol in the presence of sucrose, glucose and polyols like mannitol and maltitol. In both cow and buffalo milk samples the standardized methodology performed well in detection of sorbitol. The method also performed well in sorbitol spiked formalin preserved milk samples. This method can be an alternative to the other methods involving costly equipment in detecting adulteration of milk with sorbitol.

Plasticizer concentration effect on films and coatings based on poly(vinyl alcohol) and cationic starch blends

Films based on poly(vinyl alcohol) (PVA) and cationic starch (CS) were combined with different percentages of sorbitol (S; 15.0, 22.5, and 30.0% w v-1) to assess the effect of plasticizer on the films. Spectroscopic analyses confirmed the interaction between them. However, micrographs indicated the formation of sorbitol crystals on the surface of the films, especially at higher sorbitol concentrations. The blends presented low water vapor transmission rate values, reaching (7.703 ± 0.000) g h-1 m-2 (PVA75CS25S15), and low solubility values for the films containing higher CS amounts. The lack of statistical differences in most parameters suggests that no significant gain comes from increasing the amount of sorbitol at percentages higher than 15%. As a coating, the blend PVA75CS25S15 successfully decreased the loss of moisture content in acerolas by 1.15 times (compared to the control), confirming the suitability of this matrix as a fruit coating.

Effects of polyol and surfactant plasticisers on lyophilised rice starch wafers for buccal drug delivery

Rice starch is a promising biopolymer for buccal formulations but typical oven drying may promote starch retrogradation that affects mechanical properties. Hence, lyophilisation was proposed here to improve starch product's stability. This study aims to investigate the effects of plasticisers (sorbitol and Tween® 80, T80) on the characteristics and drug release profiles of lyophilised rice starch wafers incorporated with propranolol hydrochloride. The wafers were prepared by lyophilising starch mixture (5%w/v) with plasticiser (0.2 and 0.3 g/g) and drug (10, 20, 30%w/w). Control wafers exhibited loose layers with rough wrinkled surface. Sorbitol resulted in a dense structure with higher puncture strength (PS) but lower water absorption capacity (WAC) while T80 loosened the flakes that reduced PS and increased WAC. Drug inclusion decreased PS and increased WAC of unplasticised wafers. T80-plasticised wafers with drug had a lower PS and higher WAC than sorbitol-plasticised wafers. Particularly, T80-plasticised wafers achieved outstandingly high PS and the lowest WAC at 30%w/w drug. Drug dissolution of wafers relied mainly on the drug crystallinity and WAC at 10 and 30%w/w drug. Plasticisers reduced and increased drug dissolution at 10 and 20%w/w drug, respectively. This study highlights the potential of lyophilisation in preparing rice starch wafers for buccal delivery.

Uncovering the role of sorbitol in Renilla luciferase kinetics: Insights from spectroscopic and molecular dynamics studies

Renilla luciferase catalyzes the oxidation of coelenterazine to coelenteramide, resulting in the emission of a photon of light. This study investigated the impact of sorbitol on the structural and kinetic properties of Renilla luciferase using circular dichroism, fluorescence spectroscopy, and molecular dynamics simulations. Our investigation, carried out using circular dichroism and fluorescence analyses, as well as a thermal stability assay, has revealed that sorbitol induces conformational changes in the enzyme but does not improve its thermal stability. Moreover, through kinetic studies, it has been demonstrated that at a concentration of 0.4 M, sorbitol enhances the catalytic efficiency of Renilla luciferase. However, at higher concentrations, sorbitol results in a decrease in catalytic efficiency. Additionally, molecular dynamics simulations have shown that sorbitol increases the presence of hydrophobic pockets on the enzyme's surface. These simulations have also provided evidence that at a concentration of 0.4 M, sorbitol facilitates substrate access to the active site of the enzyme. Nevertheless, at higher concentrations, sorbitol obstructs substrate trafficking, most likely due to its impact on the gateway to the active site. This study may provide insights into the kinetic changes observed in enzymes with buried active sites, such as those with α/β hydrolase fold.

Mitigation of lens opacification by a functional food in a diabetic rodent model

The current study was designed to test a functional food (FF) mixture containing aldose reductase inhibitors and antiglycation bioactive compounds for suppressing the onset and progression of cataracts in a diabetic rat model. Two-month-old Sprague Dawley rats were grouped as control (C), diabetes untreated (D), and diabetic rats treated with FF at two doses (FF1 = 1.35 g and FF2 = 6.25 g/100g of diet). Diabetes was induced by a single injection of streptozotocin. The FF is a mixture of amla, turmeric, black pepper, cinnamon, ginger, and fenugreek added to the rodent diet. The status of cataracts was monitored weekly by a slit lamp examination for 20 weeks, after which animals were sacrificed to collect eye lenses. Feeding FF1 and FF2 to diabetic rats yielded a significant anti-hyperglycaemic effect and marginally prevented body weight loss. FF delayed cataract progression, and FF2 showed better efficacy than FF1. FF prevented the loss of lens crystallins and their insolubilization in diabetic rats. The antioxidant potential of FF was evident with the lowered protein carbonyls, lipid peroxidation, and prevention of altered antioxidant enzyme activities induced by diabetes. These studies demonstrate the efficacy of plant-derived dietary supplements against the onset and progression of cataracts in a well-established rat model of diabetic eye disease.

Low molecular weight carbohydrate patterns of mangrove macroalgae from different climatic niches under ocean acidification, warming and salinity variation

Ocean acidification has increased due to the enhanced solubility of CO2 in seawater. Mangrove macroalgae in tropical and subtropical coastal regions can benefit from the higher availability of CO2 for photosynthesis and primary production. However, they can be negatively affected by the simultaneously occurring warming and increased salinity in estuaries. Thus, we analyzed the isolated effects of ocean acidification and the interactive effects of increased temperature and salinity on the low molecular weight carbohydrate (LMWC) contents of the mangrove red macroalgae Bostrychia montagnei and Bostrychia calliptera from Brazilian tropical and subtropical populations. Specimens from both climatic niches were tolerant to pH decreased by CO2 enrichment and enhanced their LMWC contents under increased availability of CO2. Specimens from both climatic niches also accumulated their dulcitol and sorbitol contents to cope with warming and salt stress. Nevertheless, temperature of 34 °C was lethal for tropical macroalgae, while 29 °C and 31 °C were lethal for subtropical B. calliptera under salinity of 35. Tropical and subtropical B. montagnei synthesized dulcitol (5-110 mmol kg-1 dry weight) and sorbitol (5-100 mmol kg-1 dry weight) as osmoregulatory, energy and thermal protection compounds, whereas tropical and subtropical B. calliptera synthesized mainly dulcitol (10-210 mmol kg-1 dry weight). Although digeneaside has an energy function in Bostrychia spp., it is not an osmolyte or thermal protection compound. Our data demonstrated that both tropical and subtropical Bostrychia spp. benefit from ocean acidification by CO2 enrichment, increasing their LMWC contents. However, warming and increased salinity in estuaries will be detrimental to them, even they producing protective metabolites. Multifactorial approaches are recommended to investigate whether negative effects of increased temperature and salinity nullify positive effects of ocean acidification on these Bostrychia species/populations.

Analysis of the browning reaction in a sorbitol/glycine model: Formation and degradation of precursors, glucose and α-dicarbonyl compounds during heating

Browning can occur in the matrices of alditol and amino acids due to heating or long-term storage, which poses challenges in achieving the desired appearance stability. To investigate the mechanism of browning in the sorbitol-glycine system, we evaluated the evolution of typical intermediates, including glucose and α-dicarbonyl compounds (α-DCs), during heating at 100 ˚C. The browning index and intermediate products of the sorbitol-glycine system increased more rapidly compared to those of the sorbitol system. After heating for 10 h, the browning index of the sorbitol-glycine system was eight times higher than that of sorbitol alone. In the presence of glycine, sorbitol underwent continuous conversion into glucose. After 10 h of heating, the concentration of glucose in the sorbitol-glycine system reanched 726.6 mg/L, which was approximately 63 times higher than that in the sorbitol system. Mass spectrometry analysis revealed the presence of α-DCs such as 3-deoxyglucosone (3-DG), glyoxal (GO), methylglyoxal (MGO), 2,3-butanedione (2,3-BD), in the sorbitol-glycine system. These compounds were precursors of melanoidins, indicating the occurrence of the Maillard reaction and resulting in the browning of the system. Therefore, the browning process in the sorbitol-glycine system involved two stages of reactions: the conversion of sorbitol to glucose and the Maillard reaction between glucose and glycine.

Gelatin and gelatin/starch-based films modified with sorbitol for wound healing

Gelatin-based films modified with sorbitol were produced from gelatin solution or gelatin/starch blends using a simple and low-cost solvent casting method, and subsequently, their physicochemical, mechanical, and biocompatibility properties were characterized. This work focused on developing and optimizing a biopolymeric blend to improve the pure biopolymers' properties for potential biomedical applications such as wound dressing. The films were characterized in terms of morphology and transparency, mechanical, moisture and swelling properties, thermal stability, and degradation potential. Moreover, hemocompatibility, as well as cytocompatibility of prepared films, were examined. The addition of sorbitol contributed to improving mechanical properties, swelling reduction, and increasing biostability over time. The cytocompatibility of obtained films was confirmed in vitro with two different human cell lines, fibroblastic and osteoblastic, and a more favorable cellular response was received for fibroblasts. Further, in hemocompatibility studies, it was found that all films may be classified as non-hemolytic as they did not have a negative effect on the human erythrocytes. The obtained results indicate the great potential of the gelatin/starch blends modified with sorbitol as regenerative biomaterials intended for wound healing applications.

Combined PMM2-CDG and hereditary fructose intolerance in a patient with mild clinical presentation

We report a patient with an extremely rare, combined diagnosis of PMM2-CDG and hereditary fructose intolerance (HFI). By comparing with other patients, under-galactosylation was identified as a feature of HFI. Fructose/sorbitol/sucrose restriction was initiated right afterwards. The patient is at the mild end of the PMM2-CDG spectrum, raising the question of sorbitol's role in the pathogenesis of PMM2-CDG and whether fructose/sorbitol/sucrose restriction could benefit other PMM2-CDG patients. Additionally, epalrestat, an emerging potential PMM2-CDG therapy, may benefit HFI patients.

Preclinical evaluation of 2-[18F]fluorodeoxysorbitol as a tracer for targeted imaging of Enterobacterales infection

Fluorine-18-fluorodeoxyglucose ([¹⁸F]FDG) positron emission tomography (¹⁸F-FDG-PET) is widely used for the detection of inflammatory and infectious diseases. Although this modality has proven to be a useful diagnostic tool, reliable distinction of bacterial infection from sterile inflammation or even from a malignancy remains challenging. Therefore, there is a need for bacteria-specific tracers for PET imaging that facilitate a reliable distinction of bacterial infection from other pathology. The present study was aimed at exploring the potential of 2-[¹⁸F]-fluorodeoxysorbitol ([¹⁸F]FDS) as a tracer for detection of Enterobacterales infections. Sorbitol is a sugar alcohol that is commonly metabolized by bacteria of the Enterobacterales order, but not by mammalian cells, which makes it an attractive candidate for targeted bacterial imaging. The latter is important in view of the serious clinical implications of infections caused by Enterobacterales. Here we demonstrate that sorbitol-based PET can be applied to detect a broad range of clinical bacterial isolates not only in vitro, but also in blood and ascites samples from patients suffering from Enterobacterales infections. Notably, the possible application of [¹⁸F]FDS is not limited to Enterobacterales since Pseudomonas aeruginosa and Corynebacterium jeikeium also showed substantial uptake of this tracer. We conclude that [¹⁸F]FDS is a promising tracer for PET-imaging of infections caused by a group of bacteria that can cause serious invasive disease.

Effect of sorbitol on the in vitro starch digestibility in semi-dried black highland barley noodles

Sorbitol is commonly used in semi-dried noodles for holding water, thus extending the shelf life. This research analyzed the effect of sorbitol on the in vitro starch digestibility in semi-dried black highland barley noodles (SBHBN). In vitro starch digestion revealed that the hydrolysis extent and digestive rate decreased with increasing sorbitol addition, although its inhibition abated when added >2 %. Compared with the control, adding 2 % of sorbitol lowered the equilibrium hydrolysis (C_∞) significantly (P < 0.05) from 75.18 to 66.57 % and decreased the kinetic coefficient (k) significantly (P < 0.05) by 20.29 %. Adding sorbitol increased the tightness of microstructure, relative crystallinity, V-type crystal, molecular structure order, and hydrogen bond strength of starch in cooked SBHBN. Meanwhile, gelatinization enthalpy change (ΔH) of starch in raw SBHBN was increased by adding sorbitol. In addition, the swelling power and amylose leaching in SBHBN added with sorbitol were reduced. Pearson correlations analysis observed significant (P < 0.05) correlations among short-range ordered structure, ΔH, and related in vitro starch digestion indexes of SBHBN after being added with sorbitol. These results revealed that sorbitol might form hydrogen bonds with starch, making it a potential additive to lower the eGI in starchy foods.

Effects of Magnesium on nitrate uptake and sorbitol synthesis and translocation in apple seedlings

Both magnesium (Mg) and nitrogen (N) play many important roles in plant physiological and biochemical processes. Plants usually exhibit low nitrogen utilization efficiency (NUE) under Mg deficiency conditions, but the mechanisms by which Mg regulates NUE are not well understood. Herein, we investigated biomass, nutrient uptake, sorbitol and sucrose transport, and relative gene expression in apple seedlings under various concentrations of Mg and N treatments in hydroponic cultures. We first observed that low Mg supply significantly limited plant growth and N, Mg concentrations. Increasing the supply of N, but not Mg, partially alleviated the inhibition of plant growth under low Mg stress, which indicated that Mg deficiency had a negative impact on plant growth because it inhibits N absorption. Moreover, we found that the expression of nitrate transporter genes MdNRT2.1 and MdNRT2.4 was significantly downregulated by low Mg stress, and sufficient Mg significantly promoted sucrose and sorbitol synthesis and transport from leaves to roots by regulating relevant enzyme activity and genes expression. Further experiments showed that exogenous sorbitol could rapidly restore MdNRT2.1/2.4 expression and nitrate uptake under low Mg availability without increasing internal Mg level, suggesting that Mg may regulate MdNRT2.1/2.4 expression by regulating more sorbitol transport to roots, the effect of Mg on N was indirect, sorbitol played a key role during this process. Taken together, Mg promoted sorbitol synthesis and transport into roots, thus upregulating the expression of MdNRT2.1/2.4 and increasing the absorption of nitrate.

Phosphorylation of aldose-6-phosphate reductase from Prunus persica leaves

Sugar-alcohols are major photosynthates in plants from the Rosaceae family. Expression of the gene encoding aldose-6-phosphate reductase (Ald6PRase), the critical enzyme for glucitol synthesis in rosaceous species, is regulated by physiological and environmental cues. Additionally, Ald6PRase is inhibited by small molecules (hexose-phosphates and inorganic orthophosphate) and oxidizing compounds. This work demonstrates that Ald6PRase from peach leaves is phosphorylated in planta at the N-terminus. We also show in vitro phosphorylation of recombinant Ald6PRase by a partially purified kinase extract from peach leaves containing Ca²⁺-dependent protein kinases (CDPKs). Moreover, phosphorylation of recombinant Ald6PRase was inhibited by hexose-phosphates, phosphoenolpyruvate and pyrophosphate. We further show that phosphorylation of recombinant Ald6PRase was maximal using recombinant CDPKs. Overall, our results suggest that phosphorylation could fine-tune the activity of Ald6PRase.

Effects of sorbitol-mediated curing on the physicochemical properties and bacterial community composition of loin ham during fermentation and ripening stages

In this study, the impacts of loin ham with sorbitol-mediated curing on its physicochemical properties and bacterial community composition during fermentation and ripening were investigated. The salt content, pH, and water activity (a_w) were lower in the sorbitol group than in the control group throughout the fermentation and ripening stages (P < 0.05). In addition, the L* values were higher in the sorbitol group (P < 0.05). Additionally, microbial diversity diminished in all groups as the fermentation and ripening process proceeded, with Lactobacillus turning into the dominant genus in the control group and Staphylococcus and Lactobacillus becoming dominant in the sorbitol group. Pearson's correlation analysis confirmed that the physicochemical properties have been significantly correlated with the bacterial community. In conclusion, sorbitol-mediated curing not only facilitates salt reduction while prolonging the storage period of loin ham, but also improves the distribution of bacterial community in loin ham and enhances its quality.

Optimized formulation buffer preserves adeno-associated virus-9 infectivity after 4 °C storage and freeze/thawing cycling

Adeno-associated virus (AAV) have long been one of the most common and versatile vectors for in vitro and in vivo gene transfer. AAV production protocols are complex and time consuming, one key concern is the recovery and infectivity of viral vector after purification. The buffer used in the storage of AAV at 4 °C and - 80 °C is a crucial factor and methods to improve it have been thoroughly investigated. Viral core facilities have developed formulas using either 0.001% Pluronic F68 or 5% sorbitol in their storage buffers based on the results of this research. Interestingly, few use formulations that include both a non-ionic surfactant and cryopreservative. In this study, AAV9 stored at 4 °C and at - 80 °C in the standard buffers is compared to a buffer that contains 5% glycerol and 0.001% Pluronic F68. By viral genome quantitation with qPCR, all three formulations show the same extent of viral titer loss at 4 °C, while after several cycles of freeze/thaws at - 80 °C, the viral recovery and infectivity in the preparation with both glycerol and Pluronic F68 was most stable compared to the other buffers.

Polyol and sugar osmolytes stabilize the molten globule state of α-lactalbumin and inhibit amyloid fibril formation

Protein misfolding and aggregation are associated with several human diseases such as Alzheimer's, Parkinson's, prion related disorders, type-II diabetes, etc. Different strategies using molecular chaperones, synthetic and naturally occurring small molecules, osmolytes, etc. have been used to prevent protein aggregation and amyloid fibril formation. In this study, we have used bovine α-lactalbumin at pH 1.6, 37 °C, and shaking conditions to promote amyloid fibril formation. Polyol and sugar osmolytes like glycerol, sorbitol, and trehalose have been used to inhibit the fibrillation of a number of proteins. In the present work, amyloid fibril formation of α-lactalbumin has been shown by ThT assay and AFM, while changes in the secondary structure during fibrillation has been followed by circular dichroism spectroscopy. Our results show that glycerol, sorbitol, and trehalose affect amyloid fibril formation of α-lactalbumin in a concentration-dependent manner. There is a delay in the lag phase of amyloid fibril formation in sorbitol and trehalose and complete inhibition in 6 M glycerol. Our results indicate that delay in the lag phase and inhibition of amyloid fibril formation are due to the stabilization of molten globule state by these osmolytes. At pH 1.6, the molten globule as well as the amyloid fibrils bind to ANS. However, when pH was shifted from 1.6 to 7, only the oligomeric and the fibrillar species bind to ANS due to refolding of molten globule state. The outcome of this study might be useful in designing small molecules which may stabilize the intermediate states, thus preventing amyloid fibril formation.

An engineered non-oxidative glycolytic bypass based on Calvin-cycle enzymes enables anaerobic co-fermentation of glucose and sorbitol by Saccharomyces cerevisiae

BACKGROUND

Saccharomyces cerevisiae is intensively used for industrial ethanol production. Its native fermentation pathway enables a maximum product yield of 2 mol of ethanol per mole of glucose. Based on conservation laws, supply of additional electrons could support even higher ethanol yields. However, this option is disallowed by the configuration of the native yeast metabolic network. To explore metabolic engineering strategies for eliminating this constraint, we studied alcoholic fermentation of sorbitol. Sorbitol cannot be fermented anaerobically by S. cerevisiae because its oxidation to pyruvate via glycolysis yields one more NADH than conversion of glucose. To enable re-oxidation of this additional NADH by alcoholic fermentation, sorbitol metabolism was studied in S. cerevisiae strains that functionally express heterologous genes for ribulose-1,5-bisphosphate carboxylase (RuBisCO) and phosphoribulokinase (PRK). Together with the yeast non-oxidative pentose-phosphate pathway, these Calvin-cycle enzymes enable a bypass of the oxidative reaction in yeast glycolysis.

RESULTS

Consistent with earlier reports, overproduction of the native sorbitol transporter Hxt15 and the NAD⁺-dependent sorbitol dehydrogenase Sor2 enabled aerobic, but not anaerobic growth of S. cerevisiae on sorbitol. In anaerobic, slow-growing chemostat cultures on glucose-sorbitol mixtures, functional expression of PRK-RuBisCO pathway genes enabled a 12-fold higher rate of sorbitol co-consumption than observed in a sorbitol-consuming reference strain. Consistent with the high K_m for CO₂ of the bacterial RuBisCO that was introduced in the engineered yeast strains, sorbitol consumption and increased ethanol formation depended on enrichment of the inlet gas with CO₂. Prolonged chemostat cultivation on glucose-sorbitol mixtures led to loss of sorbitol co-fermentation. Whole-genome resequencing after prolonged cultivation suggested a trade-off between glucose-utilization and efficient fermentation of sorbitol via the PRK-RuBisCO pathway.

CONCLUSIONS

Combination of the native sorbitol assimilation pathway of S. cerevisiae and an engineered PRK-RuBisCO pathway enabled RuBisCO-dependent, anaerobic co-fermentation of sorbitol and glucose. This study demonstrates the potential for increasing the flexibility of redox-cofactor metabolism in anaerobic S. cerevisiae cultures and, thereby, to extend substrate range and improve product yields in anaerobic yeast-based processes by enabling entry of additional electrons.

Effects of sugar-free polyol chewing gums on gingival inflammation: a systematic review

OBJECTIVES

A systematic review of published data was conducted with the aim of assessing the effects of sugar-free polyol chewing gums on gingival inflammation.

MATERIALS AND METHODS

Electronic and hand searches were performed to find clinical studies concerning the effects of sugar-free chewing gums on gingival scores. Prospective randomized controlled clinical trials published between 1971 and 2021 were included in the review.

RESULTS

The initial search identified 46 erythritol, 102 xylitol, 23 sorbitol, and nine maltitol chewing gum articles. After applying inclusion and exclusion criteria, seven xylitol chewing gum studies, one sorbitol, and one maltitol chewing gum study with either high or fair quality were reviewed. In five out of the seven xylitol studies, xylitol gum decreased gingival scores. In two studies, xylitol decreased gingival scores compared to a polyol gum, and in three studies compared to no gum/gum base. As for sorbitol and maltitol, only sorbitol gum chewing showed a small decrease in gingival scores compared to the controls.

CONCLUSIONS

Habitual xylitol gum chewing may reduce gingival inflammation. The low number of studies and their heterogeneity provide clear indications that the effects of sugar-free polyol chewing gums on gingival inflammation need further, well-controlled studies.

CLINICAL RELEVANCE

Sugar-free chewing gums, especially xylitol gum, may function as adjuncts to toothbrushing for reducing gingival inflammation, but the evidence so far is inconclusive.

Elevated cerebrospinal fluid glucose levels and diabetes mellitus are associated with activation of the neurotoxic polyol pathway

AIMS/HYPOTHESIS

During hyperglycaemia, some glucose bypasses glycolysis and is metabolised via the potentially neurotoxic polyol pathway, in which glucose is metabolised to sorbitol and fructose. Increased polyol concentrations have been demonstrated in the cerebrospinal fluid (CSF) of neurological patients with and without diabetes mellitus. However, polyol levels in patients without evident neurological abnormalities have not been investigated so far. The aim of this study was to determine CSF polyol concentrations in patients without major neurological disease with normal or elevated CSF glucose concentrations.

METHODS

This observational cohort study used CSF and plasma analyses, as well as clinical data, from 30 participants of the Anaesthetic Biobank of Cerebrospinal Fluid study. Biomaterial was collected from adult patients scheduled for elective surgery under spinal anaesthesia. CSF polyol concentrations were measured by GC/flame ionisation detector in ten patients with normal CSF glucose levels (group 1), ten patients with elevated CSF glucose levels (group 2) and ten patients with elevated CSF glucose levels and type 2 diabetes (group 3). We compared the concentrations of plasma glucose, CSF glucose, sorbitol and fructose, and CSF polyol/glucose ratios between the three groups, and determined the correlation between plasma glucose levels and CSF glucose, sorbitol and fructose levels.

RESULTS

Groups 2 and 3 had significantly higher CSF fructose levels compared with group 1 (p=0.036 and p<0.001, respectively). Group 3 showed significant differences compared with groups 1 and 2 for CSF sorbitol (p<0.001 and 0.036, respectively). Moreover, patients with diabetes had a significantly higher CSF sorbitol/glucose ratio compared with patients without diabetes. There was a strong positive correlation between plasma glucose and CSF glucose, sorbitol and fructose. Finally, age, sex, CSF/plasma albumin ratio and preoperative cognitive function scores were significantly correlated with plasma glucose and CSF glucose, sorbitol and fructose levels.

CONCLUSIONS/INTERPRETATION

Hyperglycaemia causes a proportional increase in polyol concentrations in CSF of patients without major neurological disease. Furthermore, this study provides the first indication of upregulation of the cerebral polyol pathway in patients with diabetes without evident neurological abnormalities.

Multi-stimuli-responsive photonics films based on chiral nematic cellulose nanocrystals

Multiple-stimuli-responsive bio-based materials have received considerable attention for intelligent packaging and anti-counterfeiting applications. Herein, we present a unique biobased photonics film with multi-stimuli responsive behavior based on cellulose nanocrystals (CNCs), sorbitol (S) and anthocyanin (Anth). The resulting photonics film exhibits multi-stimuli responsive behavior to humidity, solvent and pH stimuli. Notably, the photonics film showed dramatic invertible color from blue to fuchsia and high sensitivity at a relative humidity from 50% to 100%. Moreover, the photonics film exhibited fast response and good reversibility under different ethanol concentrations. Significant color changes of the photonics film were also observed in response to pH change in the range of 2 to 12. Particularly, the humidity, solvent and pH responsiveness of the photonics film did not interfere with each other.

Hydrotropism: Analysis of the Root Response to a Moisture Gradient

Plant adaptation to environmental stress generated by low water availability requires continuous search for moisture niches in the soil. Thus, roots have evolved a hydrotropic response to sense differences in water potential of the soil, and through asymmetric growth, roots can bend to avoid lower water potential sites. Different experimental systems have been devised for hydrotropism assays, which usually rely on air moisture or split agar assays. This latter system uses plates containing an osmolyte only in a region of the plate in order to generate a water potential gradient. Seedlings are placed on the agar plate containing normal medium (NM) so that their root tips are near the junction between NM and the region supplemented with the osmolyte. As a result, a hydrotropic response is elicited to avoid the low water potential medium, which is reflected in the root curvature angle.

Effects of xylitol chewing gum and candies on the accumulation of dental plaque: a systematic review

Objectives

A systematic review of published data was conducted with the aim of assessing the effects of xylitol consumption on the amount of dental plaque.

Materials and methods

Electronic and hand searches were performed to find clinical studies concerning the effects of xylitol chewing gum or candies on dental plaque. Prospective randomized controlled clinical trials published between 1971 and 2020 conducted in healthy subjects were included in the review.

Results

The initial search identified 424 xylitol articles. After applying inclusion and exclusion criteria, altogether 14 articles (16 studies) were reviewed. The review identified 12 of the total of 14 xylitol chewing gum studies as having fair or high quality. In 13 of the 14 chewing gum studies, xylitol gum decreased plaque accumulation. In six studies, xylitol gum chewing decreased plaque compared to sorbitol gum, and in three studies compared to gum base/no gum. In three fair-quality studies conducted with xylitol candies, plaque accumulation did not change.

Conclusions

Habitual xylitol gum chewing appears to show plaque-reducing effects that differ from those of sorbitol gum. This suggests specific effects for xylitol on plaque accumulation. Xylitol candies appear not to decrease plaque. The heterogeneity of the studies warrants further research.

Clinical relevance

Habitual xylitol gum chewing is likely to decrease plaque.

Synthesis and characterization of sorbitol laced hydrogel-forming microneedles for therapeutic drug monitoring

The dermal interstitial fluid (ISF) is rich in biomarkers that are of great heuristic value for disease diagnosis and therapeutic drug monitoring. Nevertheless, the current strategies for sampling dermal ISF are both technical and invasive, limiting the potential utility of ISF for clinical medicine and research purposes. In the current work, we present, for the first time, the development, characterization, and evaluation of a novel sorbitol-laced hydrogel-forming microneedles (Sor-Hyd-MN) for sampling dermal ISF. The hydrogel system is fabricated from sorbitol and PEG 10,000 crosslinked with Gantrez® S-97 via esterification in a solvent-free manner. The sorbitol-laced hydrogel rapidly absorbs fluid when placed in aqueous media, reaching a total rise in the mass of 685% relative to the control hydrogel that only reached 436% within 15 mins. When formulated into MNs, the Sor-Hyd-MN exhibited significantly superior (p < 0.001) mechanical properties as evidenced by the minimal MN height reduction (0.9%) relative to the control-MN (3.9%) and Man-Hyd-MN (28.5%) when subjected to a compressive force of 32 N, an analog of patients' thumb pressure. The skin insertion capability of the Sor-Hyd-MN and the control-MN formulation was demonstrated using the in vitro skin simulant, Parafilm® M, and ex vivo neonatal porcine skin. When inserted into ex vivo neonatal porcine skin, the Sor-Hyd-MN showed rapid imbibement of dermal ISF within 15 mins, evidenced via the formation of swollen microchannels, which was 1.2-folds wider than the control formulation. In addition, we also demonstrated for the first time that incorporating sorbitol into Gantrez® S-97 hydrogel-forming MN improved the utility of this formulation in sampling dermal ISF. This was shown from the capability of the Sor-Hyd-MN in extracting the model compounds, isoniazid and theophylline, present within the ISF of ex vivo porcine skin. The Sor-Hyd-MN exhibited an extraction efficiency of 52.4% for isoniazid and 54.4% for theophylline which was significantly higher (p < 0.05) relative to the control formulation in a simple and straightforward manner. This work illustrates that incorporating a hyperosmolyte, such as sorbitol, can further enhance the potential utility of hydrogel-forming MN as a minimally-invasive tool for ISF sampling while providing a potential strategy to extract analytes with ease for subsequent sample analysis.

The effect of relative humidity and formulation variables on chewable xylitol-sorbitol tablets

Changing relative humidity levels challenge the manufacturing of chewable xylitol-sorbitol based tablets. The aim of the study is to investigate how the formulation of chewable xylitol-sorbitol tablets affects the properties of the powder blends and the tablets in an environment of different relative humidity levels. In all, 30 batches containing different ratios of sorbitol, xylitol and magnesium stearate were prepared at three different relative humidity levels. Powder blends were made into tablets using an instrumented eccentric tableting machine. To demonstrate the effect of variables on powder blend and tablet properties, multiple linear regression analysis was performed. It was found that xylitol-sorbitol powder blends and tablets benefitted from the large amount of magnesium stearate, and the high lubricant level negatively affected the quality of the tablets only at high relative humidity. In the presence of high environmental humidity, the amount of sorbitol in the powder mixture must be limited in order to prevent sticking whereas at low relative humidity, higher content of sorbitol is needed to decrease the friability of tablets. Results indicate that alternating relative humidity levels truly challenge the production of xylitol-sorbitol based tablets and if the humidity is not controllable, there is a need for additional filler-binders.

Influence of the source of starch and plasticizers on the environmental burden of starch-Brazil nut fiber biocomposite production: A life cycle assessment approach

Amidst the global plastic pollution crisis, bio-based polymers have been proposed as a potential substitute to tackle this issue. Owed to their biodegradability, biopolymers are generally regarded as eco-friendly during the post-consumer (disposal) stage. However, the environmental burden of the many production processes biopolymers and their components undergo better reflect the sustainable nature of these materials. Previous studies evaluating the Life Cycle Assessment (LCA) of starch-based composites have focused on commercially available starches, although other non-conventional starches can also be used to produce biopolymers. To address this knowledge gap, in the present study we evaluated the LCA of starch-Brazil nut fiber biocomposites prepared with starch from three different sources, Andean potato, corn, and sweet potato, and applying two different plasticizers, glycerol and sorbitol. Results indicated that the starch-based biocomposites were less impacting than conventional PLA-Brazil nut fiber and PP-glass fiber composites. The type of starch and plasticizer significantly influenced the environmental load of the production of the composites. The main drivers of these differences were the multiple agricultural practices, such as irrigation and fertilization, and the crop efficiency for starch extraction. Sorbitol was found to be many times more impacting than glycerol in most categories, which is due to the complex processing of sorbitol and high content in biocomposites with similar mechanical properties than glycerol. Additionally, Brazil nut fibers are presented as an eco-friendly and low-burden natural filler due to their easy processing and agricultural waste origin. The limitations, applications, and significance of the results were discussed.

Effects of low-molecular-weight polyols on the hydration status of the light-harvesting complex 2 from Rhodobacter sphaeroides 2.4.1

Low-molecular-weight (MW) polyols are organic osmolytes influencing water activity. We have investigated the effects of polyol molecules (glycerol and sorbitol) on the optical and triplet excitation dynamics of light-harvesting complex 2 (LH2) from Rhodobacter (Rba.) sphaeroides in buffer-detergent solutions. The resonance Raman spectroscopy demonstrated that, on increasing glycerol and sorbitol volume fractions ranging from 0 to 80% (v/v) (accompanied by the decreasing water activities), the planar and all-trans conformation of carotenoids (Crts) remained unchanged, and the bacteriochlorophyll a (BChl) Q_y absorption intensity decreased. The B850 fluorescence amplitude elevated in the 20-80% v/v sorbitol and 20-40% v/v glycerol solution, but decreased in 80% v/v glycerol solution. The change of ³[Crt*-BChl] interaction bands caused by ³Crt*-BChl interaction had no obvious correlation with water activities against polyol volume fractions, which are rationalized by the water activity sensitive of C- and N-termini of protein which binding with BChls. The results suggest that Rba. sphaeroides LH2 is more sensitive to low-molecular-weight polyols compared with that of the thermophiles purple bacterium Thermochromatium (Tch.) tepidum we had investigated before.

Evaluation of cryotolerant yeasts for the elaboration of a fermented pear beverage in Patagonia: Physicochemical and sensory attributes

The production of pome fruits as pears and apples, as well as their derived industries, is of great economic importance in North Patagonia. The elaboration of fermented beverages as cider or perry has evidenced a substantial diversification during the last years, with the evaluation of different fruit varieties, yeast starters and technological changes. In this work, two cryotolerant yeasts belonging to the species Saccharomyces uvarum were evaluated at laboratory and pilot scale in sterile and no-sterile pear must. One of the strains was originally isolated from apple chicha (strain NPCC1314) and the other from apple cider (strain NPCC1420) in Patagonia. Both physicochemical and sensory features of the fermented products were evaluated. Both strains were able to successfully complete the fermentations, although strain NPCC1420 showed the better kinetic properties including a faster sugar consumption than the strain NPCC1314. Both strains showed excellent implantation capacity, but the fermented products showed different chemical profiles. The perry fermented with the strain NPCC1314 was characterized by better sensory attributes as assessed by trained panelists and a greater acceptance for untrained public than the same fermented with the strain NPCC1420. The two strains were able to consume sorbitol, both in pear must and in agar-plates supplemented with sorbitol as the sole carbon source. This ability is described for the first time in S. uvarum, at least for the two strains evaluated in this work.

Spatio-temporally expressed sorbitol transporters cooperatively regulate sorbitol accumulation in pear fruit

Sorbitol is the primary substrate translocated from source to sink in pear species. Among the many sorbitol transporters (SOTs), some are known to be involved in sorbitol accumulation in fruit; however, their particular roles are unclear. In this study, we examined the transcriptome and metabolome of a variety of pear samples from six time points to identify those SOTs. Similar to previous studies, sorbitol and sucrose differed significantly between the leaf and fruit, and sorbitol was consistently observed at higher concentrations at all time points. Interestingly, we found that sorbitol accumulation in pear fruit was cooperatively mediated by SOT3, SOT6/20, SOT19/21, and SOT22. In particular, the up-regulated SOT6/20 and SOT19/21 in fruit under 1 mg L^-1 abscisic acid and 10 mg L^-1 indole acetic acid treatments, respectively, resulted in an increased sorbitol concentration. In addition, sorbitol concentration showed positive correlations to fructose and glucose concentrations, indicating a role for sorbitol in the determination of fruit sweetness. Together with the deduced process of sugar biosynthesis, transport, conversion, and accumulation in pear, our study provides a foundation for further research into sugar accumulation processes in pear fruit, contributing to the improvement of fruit quality.

One-pot synthesis of sorbitol via hydrolysis-hydrogenation of cellulose in the presence of Ru-containing composites

The aim of this work was to study the one-pot synthesis of sorbitol via hydrolysis-hydrogenation of cellulose in the presence of Ru-containing composites based on H₃PW₁₂O₄₀ supported on ZrO₂ and Nb₂O₅ (Ru-PW/ZrO₂ and Ru-PW/Nb₂O₅). The main parameters impacted the reaction rate and yield of sorbitol, i.e. reaction conditions and type of catalyst were investigated. Ru-PW/ZrO₂ systems were more active than Ru-PW/Nb₂O₅. The yield of sorbitol was found to depend on the activation temperature of PW/ZrO₂ and PW/Nb₂O₅ which affected textural properties, the amount of acid sites and size of Ru nanoparticles. The highest 66% sorbitol yield was observed in the presence of 3%Ru-PW/ZrO₂ activated at 550 °C and 1/1 of weight ratio of cellulose/catalyst, 180 °C, 7 MPa hydrogen pressure. This catalyst was stable for three cycles of the reaction without lost of it's activity.

Inhibitory effects of sorbitol on the collapse and deterioration of gluten network in fresh noodles during storage

In this paper, the inhibitory effects of sorbitol on the collapse of gluten network and textural deterioration of fresh noodles during storage were investigated, based on the changes in macroscopic and microscopic characteristics of gluten protein. Appropriate addition (≤2%) of sorbitol increased dough viscoelasticity and extension energy. Sorbitol significantly inhibited the increase of cooking loss and adhesiveness of fresh noodles, and the decrease of hardness, springiness, LA-SRC value, and GMP weight during storage. SEM images showed that sorbitol retarded the deterioration of gluten network, with maintained continuous and ordered structure after 48 h. Sorbitol enhanced the hydrogen bond interactions in gluten system and promoted dynamic depolymerization and repolymerization of gluten protein molecules during processing and cooking, this may induce the texture stability. Sorbitol as a low-molecular polyol can inhibit the deterioration in gluten network and fresh noodle texture during storage, although showing no influence on the growth of microorganisms.

Safety of vaccines administration in hereditary fructose intolerance

Patients with hereditary fructose intolerance need to follow a life-long fructose dietary and drug restriction to prevent symptoms of intoxication. Concerns about vaccines administration have been manifested overtime, for the risk of a life-threatening acute intoxication. For this reason, at Ospedale Pediatrico Bambino Gesù we performed a deepen research from open sources, datasheets and Pharmaceutical Companies informations from the most common Italian and European vaccines, which are carried out in infancy and childhood. As a safe threshold of 2.4 mg/kg/dose was recently established for oral and parenteral (other than i.v.) route, the manuscript clarifies the safe administration of majority of vaccines in patients with hereditary fructose intolerance.

Sugar alcohols derived from lactose: lactitol, galactitol, and sorbitol

Lactose is a common natural disaccharide composed of galactose and glucose molecules. It is mainly found in the whey, the by-product of cheese and casein industries. As the supply of lactose far exceeds demand, a lot of lactose was discarded as the waste every year, which not only leads to resource waste, but also causes environmental pollution. Therefore, the deep processing of lactose as the feedstock has become a hot research topic. The lactose-derived sugar alcohols, including lactitol, sorbitol, and galactitol, have shown great potential applications not only in food manufacture, but also in pharmaceutical, cosmetic, and material fields. In this paper, we focus on the property, physiological effect, production, and application of the lactose-derived sugar alcohols. KEY POINTS: • The deep processing of lactose as the feedstock has become a hot research topic. • The lactose-derived sugar alcohols show great application values. • Recent advances in the lactose-derived sugar alcohols are reviewed.

Thermophysical and rheological properties of sorbitol + ([mmim](MeO)2PO2) ionic liquid solutions: Solubility, density and viscosity

In this study, the solubility, density and viscosity of sorbitol as a sugar alcohol in the ([mmim](MeO)₂PO₂) ionic liquid (IL) were measured. The results indicated that sorbitol is highly soluble in this IL. The Flory-Huggins model with an average value for the χ parameter was successfully applied to predict the solubility of sorbitol in IL. The thermodynamic properties such as enthalpy, entropy and Gibbs free energy of dissolution were obtained using experimental solubility data, which demonstrated that the dissolution process is endothermic and non-spontaneous and includes an entropy increase. In addition, the apparent molar volume, apparent molar expansion and thermal expansion coefficient were calculated. The study of the rheological behavior revealed that the sorbitol/IL solution is Newtonian and the Arrhenius, Litovitz, Orrick-Erbar-Type and Vogel-Fulcher-Tamman models were used to correlate the viscosity data.

Girled-induced anthocyanin accumulation in red-leafed Prunus cerasifera: Effect on photosynthesis, photoprotection and sugar metabolism

The feedback regulation of photosynthesis depends on the cooperation of multiple signals, including sugars. Herein, the effect of shoot girdling was monitored on a daily basis for three days in green- and red-leafed Prunus cerasifera plants (GLP and RLP, respectively). The effect of anthocyanin presence was investigated in terms of photosynthesis, sugar metabolism and photoprotection. Net photosynthesis (A₃₉₀) and stomatal conductance were reduced on the first day at 12:00 only in the girdled GLP (29 and 33 %, respectively). Moreover, the girdled GLP displayed at 12:00 higher sucrose, glucose and fructose concentrations than control leaves. Conversely, girdled RLP showed the first reduction of A₃₉₀ at 18:00, with no significant differences at 12:00 in sucrose and glucose concentrations. The increased biosynthesis of anthocyanins that was only detected in girdled RLP contributed to lowering the accumulation of hexoses. Overall, these results revealed a sugar-buffering role exerted by anthocyanins that positively influence the feedback regulation of photosynthesis. Moreover, non-photochemical quenching, namely pNPQ, revealed the ability of anthocyanins to photoprotect photosystem II from supernumerary photons reaching the chloroplast, whose function was compromised by girdling. The present study provides a starting point to understand the possible link between photosynthesis regulation through sugar signalling and anthocyanin upregulation.

Plasticizer types affect quality and shelf life of eggs coated with rice protein

The aim of study was evaluate the effect of using rice protein coating with different plasticizers types on the quality of eggs storaged at 20 °C for 6 weeks. Three hundred eggs were coated with rice protein at 8% solution combined with glycerol, propylene glycol or sorbitol. Uncoated eggs showed the highest weight loss (5.31%), while rice protein with glycerol (4.29%) propylene glycol (4.13%) and sorbitol (4.07%) solutions were effective in preventing weight lost. Uncoated eggs had the worst HU (58.40), albumen (9.52) and yolk (7.06) pH, and YI (0.33) after 6 weeks of storage. The eggs coated of rice protein with glycerol, propylene glycol and sorbitol presented results with similar intern quality between them during all the storage period. However, the use of sorbitol as a plasticizer in the coating is more efficient in maintaining control of the increase in albumen pH. Scanning electron microscopy demonstrated a lower surface porosity in coated eggshell, indicating that the use of the coating may provide a protective barrier against the transfer of gases and moisture. In conclusion, the best egg protection results in terms of egg quality are obtained in eggs coated with rice protein and sorbitol.

Fabrication, optimization, and in vitro/in vivo evaluation of diclofenac epolamine flash tablet

The objective of this work was to design a diclofenac epolamine (DE) flash tablets (FTs) intended to dissolve in the mouth saliva, thereby improving the DE bioavailability and reducing its first-pass liver metabolism. Design-Expert software was used to build a 3¹.2² full factorial design (12 runs). FTs were fabricated using lyophilization process. The dissolution response was selected to pick the optimized run. The results indicate that the optimized run (R1) showed the fastest drug dissolution (total dissolution in 12 min). The predicted run (Rp) showed a desirability of about 0.93. Differential scanning calorimetry(DSC) analysis results showed a decrease in the drug melting point of the R1 formulation. Fourier-transform infrared spectroscopy (FTIR) showed the compatibility of the drug with other components of formulation, X-ray powder diffraction (XRPD) analysis showed the evolution of the drug physical state from a crystalline to an amorphous form and scanning electron microscopy(SEM) divugled the disappearance of drug crystals in gelatin strands. The results of the pharmacokinetic study performed in 6 human volunteers evidenced an increase in the maximum DE concentration in plasma and, consequently, an increased bioavailability of the FT formulation as compared with a reference formulation(Fr). Concisely, the developed FTs (R1) showed promising results which could be able to enhance oral bioavailability, reduce the therapeutic dose of the drug, and abate of the complications accompanied with conventional dosage forms. Graphical abstract.

Use of sorbitol as pharmaceutical excipient in the present day formulations - issues and challenges for drug absorption and bioavailability

Sorbitol is a popular sugar alcohol which has been used as an excipient in formulations of various drugs. Although from a safety perspective the presence of sorbitol in drug formulations does not raise a concern, reports have emerged and these suggest that sorbitol in drug formulations may alter oral absorption and bioavailability of certain drugs. The focus of this article was to review the published literature of various drugs where pharmacokinetic data has been reported for the drug alone versus drug administered with sorbitol and provide perspectives on the pharmacokinetic findings. Interestingly, for BCS class I drugs such as theophylline, metoprolol, the oral absorption, and bioavailability were generally not affected by sorbitol. However, theophylline oral absorption and bioavailability were decreased when sustained release formulation was used in place of immediate release formulation. For drugs such as risperidone (BCS class II) and lamivudine and ranitidine (BCS class III), the solution formulations showed diminished oral bioavailability in presence of sorbitol, whereas cimetidine and acyclovir (BCS class III), did not show any changes in pharmacokinetic profiles due to sorbitol. Finally, the presence of activated charcoal with sorbitol showed different pharmacokinetic outcome for BCS class I and II drugs.

Effects of sorbitol and lactate on erythropoietin production in HepG2 cells

Promotion of erythropoietin (EPO) production is important for erythropoiesis as well as cell viability. The most effective inducing factor for EPO production is hypoxia. Hypoxia inducible factor (HIF), a regulator of EPO production, is increased under hypoxic conditions and is also affected by various regulators such as sirtuin1 (SIRT1). SIRT1 is regulated by the cytoplasmic redox state, which is thought to affect EPO production. Therefore, we investigated the effects of sorbitol and lactic acid, which serve as substrates for cellular respiration and bring cells into a reduced state, on EPO production in HepG2 cells. The addition of low-concentration sorbitol to HepG2 cells produced a mildly reduced state similar to that of hypoxia and increased NAD⁺, SIRT1, and HIF-α, and EPO mRNA expression. On the other hand, lactate suppressed EPO mRNA expression at all concentrations. Inhibition of lactate production from pyruvate abolished the effect of low sorbitol concentrations on EPO mRNA expression. When low-concentration sorbitol and a reducing agent were administered simultaneously, the effect of increasing EPO mRNA expression disappeared. It was suggested that SIRT1 and EPO production increased under conditions where lactate production was not suppressed, even under mildly reduced conditions similar to hypoxia.

Techno-economic analysis of chemically catalysed lignocellulose biorefineries at a typical sugar mill: Sorbitol or glucaric acid and electricity co-production

Global concerns about depletion of fossil reserves has driven countries towards bio-economies utilising mostly first generation feedstocks. The economic viability of energy self-sufficient biorefineries processing sugarcane lignocelluloses into sorbitol or glucaric acid and electricity was investigated. Aspen Plus® simulations represented glucose conversion processes via SO₂-steam explosion or dilute acid pre-treatment, followed by enzymatic hydrolysis. The most economically viable sorbitol scenario using dilute acid pretreatment with a capital investment cost per litre of US$ 3.96/L was marginally profitable having a selling price 5% below the US$ 655/t market price. To secure private investment, the sorbitol selling price should reach US$ 1283/t.

Response of sugar metabolism in apple leaves subjected to short-term drought stress

For a comprehensive understanding of gene expression, enzyme activity and sugar concentrations in response to short-term water deficit in apple (Greensleeves), sugar-modulated gene expression and enzyme activities were analyzed. Water stress resulted in the accumulation of sorbitol, glucose, fructose, galactose and starch, accompanied by a significant reduction in photosynthesis and sucrose concentration. In response to short-term water deficits, the activities of aldose-6-phosphate reductase (A6PR; EC 1.1.1.200), sorbitol dehydrogenase (SDH; EC 1.1.1.14), neutral invertase (NINV; EC 3.2.1.26), sucrose synthase (SUSY; EC 2.4.1.13), and fructokinase (FK; EC 2.7.1.4) were higher, whereas cell wall invertase (CWINV; EC 3.2.1.26) and hexokinase (HK; EC 2.7.1.1) activities were lower. In addition, sucrose phosphate synthase (SPS; EC 2.4.1.14) activity increased during the initial stages of dehydration and then decreased as the drought strengthened. Transcript levels of MdA6PR, MdSDH1/2, MdNINV1/2, MdSUSY3, MdFK1/2/4, MdSOT1/2, MdSUC1-3, MdTMT2/3, MdvGT1, MdpGlcT1-4 were upregulated, whereas transcript levels of MdCWINV1/2, MdHK1/2/3/5, and MdTMT1 were downregulated after 6 days of water stress. These findings suggest that the sorbitol metabolism pathway is induced and high levels of hexose derived from photosynthetic products are transported into vacuoles for adjustment to the water deficit. Our results provide insights into the relationships between sugar levels and sugar-modulated gene and enzyme activity in response to the imposition of short-term water stress.

Cryopreservation of Andalusian donkey (Equus asinus) spermatozoa: Use of alternative energy sources in the freezing extender affects post-thaw sperm motility patterns but not DNA stability

The aim of this study was to compare the effect of three sugars and Equex paste in a freezing extender for donkey sperm cryopreservation. Ejaculates (n = 18) were collected from six Andalusian donkeys of proven fertility were pooled (two ejaculates per pool) and cryopreserved using a freezing extender containing three different sugars (glucose, fructose and sorbitol), with or without the addition of Equex paste. Sperm quality was assessed before and after freezing-thawing for motility, morphology, plasma membrane integrity, acrosome integrity and DNA integrity. The use of sorbitol in the freezing extender improved total and progressive sperm motility (P < 0.05) and amplitude of lateral head displacement (P < 0.01), but it reduced the values for other sperm motility variables compared with glucose (P < 0.001). The use of fructose resulted in a reduction in values for most CASA variables (P < 0.05), whereas addition of Equex paste did not have any beneficial effect on values for these variables (P > 0.05). Glucose was more effective in maintaining sperm morphology (P < 0.05), while there was no beneficial effect with the addition of Equex paste (P > 0.05). Supplementation of fructose and Equex paste in the freezing extender decreased plasma membrane integrity (P < 0.05) as compared with glucose, but there were no differences between treatments for acrosome and DNA integrity (P > 0.05), even after 24 h of incubation. The use of different sugar sources in the extender could affect the in vitro post-thaw quality of cryopreserved donkey spermatozoa, with sorbitol being an interesting alternative for improving the sperm quality. Results of the present study indicate the use of Equex paste could negatively affect post-thaw outcomes for sperm viability in this species.

Efficient synchronization of Plasmodium knowlesi in vitro cultures using guanidine hydrochloride

BACKGROUND

Long-term in vitro culture of blood stage Plasmodium parasites invariably leads to asynchronous parasite development. The most often used technique to synchronize Plasmodium falciparum culture is sorbitol treatment, which differentially induces osmotic lysis of trophozoite- and schizont-infected red blood cells due to presence of the new permeation pathways in the membranes of these cells. However, sorbitol treatment does not work well when used to synchronize the culture-adapted Plasmodium knowlesi A1-H.1 line.

METHODS

A number of common solutes were tested in lieu of sorbitol for synchronization of P. knowlesi A1-H.1 ring stage.

RESULTS

Guanidine hydrochloride was found to selectively lyse trophozoite- and schizont-infected red blood cells, yielding highly synchronous and viable rings.

CONCLUSIONS

A method for synchronization of P. knowlesi in human red blood cells was developed. Requiring only common laboratory reagents, this method is simple and should be applicable to most laboratory settings.

Continuous co-production of biomass and bio-oxidized metabolite (sorbose) using Gluconobacter oxydans in a high-oxygen tension bioreactor

High-efficiency cell proliferation of Gluconobacter oxydans was carried out in a compressed oxygen supply and sealed bioreactor to co-produce biomass and corresponding metabolite (sorbose). Higher cell density of Gluconobacter oxydans was achieved by implementing high-oxygen tension supply strategy resulting into high sorbose production from bio-oxidation of sorbitol. The highest biomass of 8.8 g/L and highest sorbose production of 432.8 g/L were simultaneously obtained after 72 h of fed-batch operation. Moreover, continuous co-production of biomass and sorbose was successfully conducted with retaining 10% sorbitol fermentation broth as the seed of next stage culture. The key features of this bioprocess application would enable cost-competitive Gluconobacter oxydans industrial applications.

Direct conversion of cellulose into sorbitol catalyzed by a bifunctional catalyst

The conversion of cellulose into sorbitol has been recognized as one of most promising biomass valorization routes for the production of high added-value chemicals. In this work, Sulfonic acid-functionalized carbonized cassava dregs supported ruthenium bifunctional catalyst (Ru/CCD-SO₃H) was prepared. The Ru/CCD-SO₃H catalyst was employed for direct conversion of cellulose into sorbitol in a neutral aqueous solution. A sorbitol yield of 63.8% could be obtained at 180 °C for 10 h. The acidic sites and metal hydrogenation sites of the Ru/CCD-SO₃H catalyst played an important role in hydrolytic hydrogenation of cellulose. Particularly, there presented a strong synergistic effect between sulfonic groups and Ru nanoparticles in conversion of cellulose into sorbitol. This synergistic effect was favorable to enhancing the sorbitol yield. Besides, the stability of Ru/CCD-SO₃H catalyst was investigated under the optimal reaction conditions. The catalytic performance of catalyst was decreased after being used five times.

Improved sorbitol production and growth in cyanobacteria using promiscuous haloacid dehalogenase-like hydrolase

Sorbitol can be produced photosynthetically in the model cyanobacterium Synechocystis sp. PCC 6803 harboring sorbitol-6-phosphate (S6P) dehydrogenase (S6PDH) from apple, representing a promising metabolic engineering strategy for environmentally friendly carbon-based compound production. However, no gene for S6P phosphatase has been reported to date. We previously found that members of the Escherichia coli haloacid dehalogenase-like hydrolase (HAD) superfamily, a group of promiscuous hydrolases, exert phosphatase activity to S6P in vitro. Here, we examined the effects of HADs on sorbitol production in cyanobacterial cells. Overexpression of E. coli HAD1 improved sorbitol production induced by toxic S6PDH, whereas it suppressed growth even without induction. Moreover, overexpression of HAD1 in combination with engineering of other pathways successfully allowed for the constitutive expression of toxic S6PDH. Consequently, the sorbitol production was highly improved, which in turn suppressed the growth suppression effect of promiscuous HAD1. These results provide a good example of a novel metabolic engineering strategy using a combination of a promiscuous enzyme with an abundant supply of one of its substrates.

Sorbitol-penetration enhancer containing vesicles loaded with baicalin for the protection and regeneration of skin injured by oxidative stress and UV radiation

Aiming at improving the protective effects of baicalin on the skin, new highly-biocompatible penetration enhancer containing vesicles (PEVs) were developed by modifying the base formulation of transfersomes with sorbitol, thus obtaining sorbitol-PEVs. An extensive evaluation of the physico-chemical features of both transfersomes and sorbitol-PEVs was carried out. Transfersomes were mainly close-packed, multi-compartment vesicles, while sorbitol-PEVs appeared mostly as single, spherical, unilamellar vesicles. All the vesicles were small in size (∼128 nm) and negatively charged (∼-67 mV), without significant differences between the formulations. The in vitro delivery of baicalin to intact skin showed an improved ability of sorbitol-PEVs to favour the deposition of the flavonoid into the whole skin. In addition, the vesicular formulations protected keratinocytes and fibroblasts from oxidative stress and UV radiation, and promoted cell proliferation and migration, which favoured the closure of skin wound. Cell uptake was promoted as well, especially when sorbitol-PEVs were used.

Identification and Mutational Analysis of Escherichia coli Sorbitol-Enhanced Glucose-Repressed srlA Promoter Expressed in LB Medium by Using Homologous Recombination and One-Round PCR Products

Escherichia coli has been used for recombinant protein production for many years. However, no native E. coli promoters have been found for constitutive expression in LB medium. To obtain high-expression E. coli promoters active in LB medium, we inserted various promoter regions upstream of eEmRFP that encodes a red fluorescent protein. Among the selected promoters, only colonies of srlA promoter transformants turned red on LB plate. srlA is a gene that regulates sorbitol utilization. The addition of sorbitol enhanced eEmRFP expression but glucose and other sugars repressed, indicating that srlAp is a sorbitol-enhanced glucose-repressed promoter. To analyze the srlAp sequence, a novel site-directed mutagenesis method was developed. Since we demonstrated that homologous recombination in E. coli could occur between 12-bp sequences, 12-bp overlapping sequences were attached to the set of primers that were designed to produce a full-length plasmid, denoted "one-round PCR product." Using this method, we identified that the srlA promoter region was 100 bp. Further, the sequence adjacent to the start codon was found to be essential for high expression, suggesting that the traditionally used restriction enzyme sites for cloning in the promoter region have hindered expression. The srlA-driven expression system and DNA manipulation with one-round PCR products are useful tools in E. coli genetic engineering.

seeds

Traditional herbal medicines are attaining more popularity and are being widely practiced. Coriandrum sativum L. is one of the oldest herbal medicinal plants valued for its nutritional and medicinal properties. Present investigation was focussed on evaluation of attenuating potential of flavonoid rich extract of C. sativum (FCS) seeds against pathogenic markers of diabetic complications i.e. advanced glycation end products (AGEs), sorbitol and aldose reductase (ALR); by using in-vitro methods. Gas chromatography-mass spectrometry (GC-MS) and Infrared spectroscopy of FCS revealed the presence of different flavonoids. Results demonstrated that FCS has produced 79.80% inhibition of AGEs formation. Additionally, FCS was effective against sorbitol accumulation and ALR inhibition with IC₅₀ values of 221 μg/ml and 6.08 μg/ml respectively. Molecular docking was conducted against three binding site for ALR, RAGEs and sorbitol dehydrogenase to explore their binding interactions with identified flavonoids. The constituents F₂, F₄ and F₆ have shown good binding interactions with all the receptors. The visualisation of the docked complexes revealed the occurrence of hydrophobic forces and hydrogen bonding in receptor and docked constituents. The results were in support with experimental inhibitory activities of FCS against these biomarkers and provide a considerable basis for the identification and development of new inhibitors.