Identification of Tellurium Metabolite in Broccoli Using Complementary Analyses of Inorganic and Organic Mass Spectrometry.

Tellurium (Te) is a chalcogen element like sulfur and selenium. Although it is unclear whether Te is an essential nutrient in organisms, unique Te metabolic pathways have been uncovered. We have previously reported that an unknown Te metabolite (UKTe) was observed in plants exposed to tellurate, a highly toxic Te oxyanion, by liquid chromatography-inductively coupled plasma mass spectrometer (LC-ICP-MS). In the present study, we detected UKTe in tellurate-exposed broccoli (Brassica oleracea var. italica) by LC-ICP-MS and identified it as gluconic acid-3-tellurate (GA-3Te) using electrospray ionization mass spectrometer with quadrupole-Orbitrap detector and tandem MS analysis, the high-sensitivity and high-resolution mass spectrometry for organic compounds. We also found that GA-3Te was produced from one gluconic acid and one tellurate molecule by direct complexation in an aqueous solution. GA-3Te was significantly less toxic than tellurate on plant growth. This study is the first to identify the Te metabolite GA-3Te in plants and will contribute to the investigation of tellurate detoxification pathways. Moreover, gluconic acid, a natural and biodegradable organic compound, is expected to be applicable to eco-friendly remediation strategies for tellurate contamination.

Enhancing Lactobacillus plantarum delivery: Impact of gluconolactone concentration on high-internal-phase emulsion gels and gastrointestinal viability.

In this study, the impact of Gluconolactone (GDL) concentration on the formation of high-internal-phase emulsion gels (HIPEGs) and the gastrointestinal digestive viability of Lactobacillus plantarum encapsulated within these HIPEGs were demonstrated. Increasing GDL concentrations led to cross-linking of particles at the oil-water interface, thereby stabilizing smaller oil droplets. The addition of GDL to HIPEs results in a significant increase in the secondary structure of SPI, specifically in ß-sheet and ß-turn formations, accompanied by a reduction in α-helix percentage. This alteration enhanced the binding effect of protein on water, leading to changes in intermolecular force. Notably, HIPEGs containing 3.0% GDL demonstrated superior encapsulation efficiency and delivery efficiency, reaching 99.0% and 84.5%, respectively. After 14 d of continuous zebrafishs feeding, the intestinal viable cells count of Lactobacillus plantarum reached 1.18 × 107 CFU/mL. This finding supports the potential use of HIPEGs as a probiotic delivery carrier, effectively enhancing the intestinal colonization rate.

Zinc for prevention and treatment of the common cold.

BACKGROUND: The common cold is an acute, self-limiting viral respiratory illness. Symptoms include nasal congestion and mucus discharge, sneezing, sore throat, cough, and general malaise. Given the frequency of colds, they are a public health burden and a significant cause of lost work productivity and school absenteeism. There are no established interventions to prevent colds or shorten their duration. However, zinc supplements are commonly recommended and taken for this purpose. OBJECTIVES: To assess the effectiveness and safety of zinc for the prevention and treatment of the common cold. SEARCH METHODS: We searched CENTRAL, MEDLINE, Embase, CINAHL, and LILACS to 22 May 2023, and searched Web of Science Core Collection and two trials registries to 14 June 2023. We also used reference checking, citation searching, and contact with study authors to identify additional studies. SELECTION CRITERIA: We included randomised controlled trials (RCTs) in children or adults that tested any form of zinc against placebo to prevent or treat the common cold or upper respiratory infection (URTI). We excluded zinc interventions in which zinc was combined with other minerals, vitamins, or herbs (e.g. a multivitamin, or mineral supplement containing zinc). DATA COLLECTION AND ANALYSIS: We used the Cochrane risk of bias tool to assess risks of bias, and GRADE to assess the certainty of the evidence. We independently extracted data. When necessary, we contacted study authors for additional information. We assessed zinc (type and route) with placebo in the prevention and treatment of the common cold. Primary outcomes included the proportion of participants developing colds (for analyses of prevention trials only), duration of cold (measured in days from start to resolution of the cold), adverse events potentially due to zinc supplements (e.g. unpleasant taste, loss of smell, vomiting, stomach cramps, and diarrhoea), and adverse events considered to be potential complications of the common cold (e.g. respiratory bacterial infections). MAIN RESULTS: We included 34 studies (15 prevention, 19 treatment) involving 8526 participants. Twenty-two studies were conducted on adults and 12 studies were conducted on children. Most trials were conducted in the USA (n = 18), followed by India, Indonesia, Iran, and Turkey (two studies each), and Australia, Burkina Faso, Colombia, Denmark, Finland, Tanzania, Thailand, and the UK (one study each). The 15 prevention studies identified the condition as either common cold (n = 8) or URTI (n = 7). However, almost all therapeutic studies (17/19) focused on the common cold. Most studies (17/34) evaluated the effectiveness of zinc administered as lozenges (3 prevention; 14 treatment) in acetate, gluconate, and orotate forms; gluconate lozenges were the most common (9/17). Zinc gluconate was given at doses between 45 and 276 mg/day for between 4.5 and 21 days. Five (5/17) lozenge studies gave acetate lozenges and two (2/17) gave both acetate and gluconate lozenges. One (1/17) lozenge study administered intranasal (gluconate) and lozenge (orotate) zinc in tandem for cold treatment. Of the 17/34 studies that did not use lozenges, 1/17 gave capsules, 3/17 administered dissolved powders, 5/17 gave tablets, 4/17 used syrups, and 4/17 used intranasal administration. Most studies were at unclear or high risk of bias in at least one domain. There may be little or no reduction in the risk of developing a cold with zinc compared to placebo (risk ratio (RR) 0.93, 95% CI 0.85 to 1.01; I2 = 20%; 9 studies, 1449 participants; low-certainty evidence). There may be little or no reduction in the mean number of colds that occur over five to 18 months of follow-up (mean difference (MD) -0.90, 95% CI -1.93 to 0.12; I2 = 96%; 2 studies, 1284 participants; low-certainty evidence). When colds occur, there is probably little or no difference in the duration of colds in days (MD -0.63, 95% CI -1.29 to 0.04; I² = 77%; 3 studies, 740 participants; moderate-certainty evidence), and there may be little or no difference in global symptom severity (standardised mean difference (SMD) 0.04, 95% CI -0.35 to 0.43; I² = 0%; 2 studies, 101 participants; low-certainty evidence). When zinc is used for cold treatment, there may be a reduction in the mean duration of the cold in days (MD -2.37, 95% CI -4.21 to -0.53; I² = 97%; 8 studies, 972 participants; low-certainty evidence), although it is uncertain whether there is a reduction in the risk of having an ongoing cold at the end of follow-up (RR 0.52, 95% CI 0.21 to 1.27; I² = 65%; 5 studies, 357 participants; very low-certainty evidence), or global symptom severity (SMD -0.03, 95% CI -0.56 to 0.50; I² = 78%; 2 studies, 261 participants; very low-certainty evidence), and there may be little or no difference in the risk of a change in global symptom severity (RR 1.02, 95% CI 0.85 to 1.23; 1 study, 114 participants; low-certainty evidence). Thirty-one studies reported non-serious adverse events (2422 participants). It is uncertain whether there is a difference in the risk of adverse events with zinc used for cold prevention (RR 1.11, 95% CI 0.84 to 1.47; I2 = 0%; 7 studies, 1517 participants; very low-certainty evidence) or an increase in the risk of serious adverse events (RR 1.67, 95% CI 0.78 to 3.57; I2 = 0%; 3 studies, 1563 participants; low-certainty evidence). There is probably an increase in the risk of non-serious adverse events when zinc is used for cold treatment (RR 1.34, 95% CI 1.15 to 1.55; I2 = 44%; 2084 participants, 16 studies; moderate-certainty evidence); no treatment study provided information on serious adverse events. No study provided clear information about adverse events considered to be potential complications of the common cold. AUTHORS' CONCLUSIONS: The findings suggest that zinc supplementation may have little or no effect on the prevention of colds but may reduce the duration of ongoing colds, with an increase in non-serious adverse events. Overall, there was wide variation in interventions (including concomitant therapy) and outcomes across the studies, as well as incomplete reporting of several domains, which should be considered when making conclusions about the efficacy of zinc for the common cold.

Higher abundance of 2-dehydro-d-gluconate in the plasma of sub-fertile or infertile Bos taurus heifers.

Infertility or subfertility impacts approximately 5% and 15% of dairy and beef heifers (Bos taurus), respectively. Heifers that do not produce a calf within an optimum window of time have a significant negative impact on the profitability and sustainability of the cattle industry. Selection of heifers based on their fertility potential remains a challenge yet to be resolved. Here, we tested the hypothesis that heifers of different fertility potential have differing metabolome signatures in their plasma. We obtained blood from Bos taurus heifers at their first artificial insemination and processed the samples to separate the plasma. The heifers were classified based on their reproductive outcome as fertile (pregnant and delivered a calf after their first artificial insemination (AI)) or sub-fertile (Angus heifers: no pregnancy after two AI and exposure to a bull; Holstein heifers: no pregnancy by the third AI). We tested the relative abundance of 140 metabolites obtained from 22 heifers (Angus fertile n = 5, Angus sub-fertile n = 7, Holstein fertile N = 5, Holstein sub-fertile N = 5). The metabolite 2-Dehydro-D-gluconate (C6H10O7) was significantly more abundant in the plasma of sub-fertile heifers in both breeds (1.4-fold, false discovery rate < 0.1). In the context that a small proportion of circulating metabolites in the plasma were quantified in this study, the results show that the metabolomic profile in the blood stream may be associated with heifer fertility potential.

During the development of heifers for cow replacement, producers must invest substantial resources in each animal for over 15 mo. While the use of resources is equivalent across heifers being developed on a farm, a substantial proportion of the animals will not produce a calf (approximately 5% and approximately 15% of dairy and beef heifers, respectively). In this study, we identified one metabolite with higher abundance in the plasma of dairy and beef heifers with low chances of producing a calf by 25 mo of age.

Self-propelled enzyme-controlled IR-mesoporous silica Janus nanomotor for smart delivery.

Here, we report the preparation of a novel Janus nanoparticle with opposite Ir and mesoporous silica nanoparticles through a partial surface masking with toposelective modification method. This nanomaterial was employed to construct an enzyme-powered nanomachine with self-propulsion properties for on-command delivery. The cargo-loaded nanoparticle was provided with a pH-sensitive gate and unit control at the mesoporous face by first attaching boronic acid residues and further immobilization of glucose oxidase through reversible boronic acid esters with the carbohydrate residues of the glycoenzyme. Addition of glucose leads to the enzymatic production of H2O2 and gluconic acid, being the first compound catalytically decomposed at the Ir nanoparticle face producing O2 and causing the nanomachine propulsion. Gluconic acid leads to a pH reduction at the nanomachine microenvironment causing the disruption of the gating mechanism with the subsequent cargo release. This work demonstrates that enzyme-mediated self-propulsion improved release efficiency being this nanomotor successfully employed for the smart release of Doxorubicin in HeLa cancer cells.

Legume milk-based yogurt mimetics structured using glucono-δ-lactone.

The potential to produce protein-structured vegan yogurts with legumes was explored to offer an alternative to conventional polysaccharide-based varieties. Glucono-δ-lactone (GDL) was employed as a slow acidifying agent and was investigated for its ability to generate cold-set, yogurt-like gels using soy and lentil milks made using minimal processing steps. Soy (5.3 % protein) and lentil (6.1 % protein) milks were successfully gelled by GDL at concentrations of 0.5 % and 1 % w/w. Soy and lentil milks experienced similar acidification profiles and demonstrated good fits with double-exponential decay models. The physical properties of these legume gels were evaluated and compared to a commercial stirred dairy yogurt. Penetration tests were carried out on intact gels, then repeated after stirring. All intact soy samples demonstrated significantly stronger gel structures compared to the commercial yogurt, and most experienced greater amounts of brittleness. Results showed that the stirring of gels caused a notable decrease in firmness and brittleness in the soy gels, making them more similar to the control. Power-law modelling of viscosity curves demonstrated that all samples experienced non-Newtonian flow behavior (n < 0.29). Susceptibility to syneresis was measured by the degree of liquid loss following centrifugation. The optimization of protein type and GDL concentration to replicate the physical properties of dairy-based yogurts can enhance their consumer acceptance and provide a more customizable and controlled approach alternative to traditional fermentation methods.

Differential Protective Effect of Zinc and Magnesium for the Hepatic and Renal Toxicity Induced by Acetaminophen and Potentiated with Ciprofloxacin in Rats.

Background and Objectives: The purpose of this study was to investigate the influence induced by magnesium chloride (MgCl2) and zinc gluconate (ZnG) supplementation on liver and kidney injuries experimentally induced with acetaminophen (AAPh) and potentiated by a ciprofloxacin addition in rats. Material and Methods: The experiment was performed on five animal groups: group 1-control, treated for 6 weeks with normal saline, 1 mL/kg; group 2-AAPh, treated for 6 weeks with AAPh, 100 mg/kg/day; group 3-AAPh + C, treated for 6 weeks with AAPh 100 mg/kg/day and ciprofloxacin 50 mg/kg/day, only in the last 14 days of the experiment; group 4-AAPh + C + Mg, with the same treatment as group 3, but in the last 14 days, MgCl2 10 mg/ kg/day was added; and group 5-AAPh + C + Zn, with the same treatment as group 3, but in the last 14 days, zinc gluconate (ZnG), 10 mg/kg/day was added. All administrations were performed by oral gavage. At the end of the experiment, the animals were sacrificed and blood samples were collected for biochemistry examinations. Results: Treatment with AAPh for 6 weeks determined an alteration of the liver function (increases in alanine aminotransferase, aspartate aminotransferase, lactic dehydrogenase, and gamma-glutamyl transferase) and of renal function (increases in serum urea and creatinine) (p < 0.001 group 2 vs. group 1 for all mentioned parameters). Furthermore, the antioxidant defense capacity was impaired in group 2 vs. group 1 (superoxide dismutase and glutathione peroxidase activity decreased in group 2 vs. group 1, at 0.001 < p < 0.01 and 0.01 < p < 0.05, respectively). The addition of ciprofloxacin, 50 mg/kg/day during the last 14 days, resulted in further increases in alkaline phosphatase, alanine aminotransferase, aspartate aminotransferase, urea, and creatinine (0.01 < p < 0.05, group 3 vs. group 2). MgCl2 provided a slight protection against the increase in liver enzymes, and a more pronounced protection against the increase in serum urea and creatinine (0.001 < p < 0.01 group 4 vs. group 3). MgCl2 provided a slight protection against the decrease in superoxide dismutase (0.01 < p < 0.05 group 4 vs. group 3), but not against decrease of glutathione peroxidase. The improvement of mentioned parameters could also be seen in the case of ZnG, to a higher extent, especially in the case of alanine aminotransferase and lactic dehydrogenase (0.01 < p < 0.05 group 5 vs. group 4). Conclusions: This study presents further proof for the beneficial effect of magnesium and zinc salts against toxicity induced by different agents, including antibacterials added to the analgesic and antipyretic acetaminophen; the protection is proven on the liver and kidney's function, and the antioxidant profile improvement has a key role, especially in the case of zinc gluconate.

Is there a fast track ("Darmstrasse") for fluids in the small intestine? Evidence from magnetic resonance imaging.

BACKGROUND: The transit and distribution pattern of fluids in the small intestine is a key parameter for the dissolution and absorption of drugs. Although some information is known about the small intestinal water content after administration of fluid volumes and meals, the intestinal transit of orally ingested fluids and solutions has been barely investigated. The aim of this three-arm, cross-over, 9-subject human study was to investigate the transit of orally ingested water in the small intestine under fasting and postprandial conditions using MRI. To identify the ingested water, manganese gluconate, which can be identified with T1-weighted MRI sequences, was added as a marker. Using Horos (DICOM software), quantification of the distribution of Mn2+ ions in the gastrointestinal tract in fasted versus fed state (standard meal by FDA guidance and a light meal) was possible. The distribution and approximate wetted intestinal length was very similar in the fasting and postprandial states, suggesting rapid transport of water ingested after a meal through the chyme-filled small intestine in continuation of the "Magenstrasse" (stomach road). In some subjects, manganese gluconate reached deeper parts of the small intestine even more quickly in the postprandial state than in the fasting arm of the study. A deeper understanding of the behaviour of solutes in the gastrointestinal tract is fundamental to a mechanistic explanation for the kinetic interaction between food and drug intake (food effects).

Gelling properties of acid-induced tofu (soybean curd): Effects of acid type and nano-fish bone.

The effects of different types of acid coagulants and nano fish bone (NFB) additives on the characteristics of tofu were investigated using texture analyzers, SEM, FT-IR, and other techniques. The breaking force and penetration distance, in descending order, were found in the tofu induced by glucono-d-lactone (GDL) (180.27 g and 0.75 cm), citric acid (152.90 g and 0.74 cm), lactic acid (123.33 g and 0.73 cm), and acetic acid (69.84 g and 0.58 cm), respectively. The syneresis of these tofu samples was in the reverse order (35.00, 35.66, 39.66, and 44.50%). Lightness and whiteness were not significantly different among the different samples. Regardless of the acid type, the soluble calcium content in the soybean milk was significantly increased after adding NFB. As a result, the breaking force and penetration distance of all tofu samples increased significantly, but the syneresis decreased. Compared with tofu coagulated by other acids, GDL tofu formed a more uniform and dense gel network maintained by the highest intermolecular forces (especially hydrophobic interactions). Regarding the secondary structure, the lowest percentage of α-helix (22.72%) and, correspondingly, the highest ß-sheet (48.32%) and random coil (18.81%) were noticed in the GDL tofu. The effects of NFB on the tofu characteristics can be explained by the changes in the gel network, intermolecular forces, and secondary structure, which were in line with the acid type. The characteristics of acid-induced tofu can be most synergistically improved by coagulation with GDL and NFB.

Dilute gluconic acid pretreatment and fermentation of wheat straw to ethanol.

Gluconic acid's potential as a wheat straw pretreatment agent was studied at different concentrations (0.125-1 M) and temperatures (160-190 °C) for 30 min, followed by enzymatic hydrolysis. 0.125 M gluconic acid, 170 °C, yielded the highest xylose output, while 0.5 M gluconic acid at 190 °C yielded the best glucose yield. A fraction of gluconic acid decomposed during pretreatment. Detoxified hemicellulose hydrolysate from 0.125 M gluconate at 170 °C for 60 min showed promise for ethanol production. The gluconate contained in the detoxified hemicellulose hydrolysate can be fermented to ethanol along with other hemicellulose sugars present by Escherichia coli SL100. The ethanol yield from gluconate and sugars was about 90.4 ± 1.8%. The pretreated solids can be effectively converted to ethanol by Saccharomyces cerevisiae D5A via simultaneous saccharification and fermentation with the cellulase and ß-glucosidase addition. The ethanol yield achieved was 92.8 ± 2.0% of the theoretical maximum. The cellulose conversion was about 70.8 ± 0.8%.

Structural effects of oxidation on sugars: glucose as a precursor of gluconolactone and glucuronolactone.

Although structural information on sugars is wide, experimental studies on the oxidation products of sugars in the gas phase, free from solvent interactions, have been rarely reported. We present an experimental work on the changes in the structure and interactions of two products of glucose oxidation (D-glucono-1,5-lactone (GlcL) and D-glucurono-6,3-lactone (GlcurL)) with respect to their precursor. Features such as intramolecular interactions, ring puckering and tautomerism were observed.

Enabling High Activation of Glucose-6-Phosphate Dehydrogenase Activity Through Liquid Condensate Formation and Compression.

Droplet formation via liquid-liquid phase separation is thought to be involved in the regulation of various biological processes, including enzymatic reactions. We investigated a glycolytic enzymatic reaction, the conversion of glucose-6-phosphate to 6-phospho-D-glucono-1,5-lactone with concomitant reduction of NADP+ to NADPH both in the absence and presence of dynamically controlled liquid droplet formation. Here, the nucleotide serves as substrate as well as the scaffold required for the formation of liquid droplets. To further expand the process parameter space, temperature and pressure dependent measurements were performed. Incorporation of the reactants in the liquid droplet phase led to a boost in enzymatic activity, which was most pronounced at medium-high pressures. The crowded environment of the droplet phase induced a marked increase of the affinity of the enzyme and substrate. An increase in turnover number in the droplet phase at high pressure contributed to a further strong increase in catalytic efficiency. Enzyme systems that are dynamically coupled to liquid condensate formation may be the key to deciphering many biochemical reactions. Expanding the process parameter space by adjusting temperature and pressure conditions can be a means to further increase the efficiency of industrial enzyme utilization and help uncover regulatory mechanisms adopted by extremophiles.

Maximizing Polysaccharides and Phycoerythrin in Porphyridium purpureum via the Addition of Exogenous Compounds: A Response-Surface-Methodology Approach.

Phycoerythrin and polysaccharides have significant commercial value in medicine, cosmetics, and food industries due to their excellent bioactive functions. To maximize the production of biomass, phycoerythrin, and polysaccharides in Porphyridium purpureum, culture media were supplemented with calcium gluconate (CG), magnesium gluconate (MG) and polypeptides (BT), and their optimal amounts were determined using the response surface methodology (RSM) based on three single-factor experiments. The optimal concentrations of CG, MG, and BT were determined to be 4, 12, and 2 g L-1, respectively. The RSM-based models indicated that biomass and phycoerythrin production were significantly affected only by MG and BT, respectively. However, polysaccharide production was significantly affected by the interactions between CG and BT and those between MG and BT, with no significant effect from BT alone. Using the optimized culture conditions, the maximum biomass (5.97 g L-1), phycoerythrin (102.95 mg L-1), and polysaccharide (1.42 g L-1) concentrations met and even surpassed the model-predicted maximums. After optimization, biomass, phycoerythrin, and polysaccharides concentrations increased by 132.3%, 27.97%, and 136.67%, respectively, compared to the control. Overall, this study establishes a strong foundation for the highly efficient production of phycoerythrin and polysaccharides using P. purpureum.

Evaluation of the operational conditions of the glucose oxidase and catalase multienzymatic system through enzyme co-immobilization on amino hierarchical porous silica.

Hexaric acids have attracted attention lately because they are platform chemicals for synthesizing pharmaceuticals. In particular, gluconic acid is one of the most studied because it is readily available in nature. In this work, operational conditions like temperature and pH were evaluated for the enzymatic production of gluconic acid. For this purpose, glucose oxidase (GOx) and catalase (CAT) were individually immobilized and co-immobilized using amino-silica as support. The catalytic performance of the enzymes both as separate biocatalysts (GOx or CAT) and as an enzymatic complex (GOx-CAT) was assessed in terms of enzymatic activity and stability at temperatures 45 °C and 50 °C and pH 6 to 8. The results show that CAT is a key enzyme for gluconic acid production as it prevents GOx from being inhibited by H2O2. However, CAT was found to be less stable than GOx. Therefore, different GOx to CAT enzymatic ratios were studied, and a ratio of 1-3 was determined to be the best. The highest glucose conversion conditions were 45 °C and pH 7.0 for 24 h. Regarding the biocatalyst reuse, GOx-CAT retained more than 70% of its activity after 6 reaction cycles. These results contribute to further knowledge and application of oxidases for hexaric acid production and shed greater light on the role of the glucose oxidase/catalase pair in better catalytic performance. Both enzymes were immobilized in one pot, which is relevant for their potential use in industry; an enzyme system was obtained in a single step.

Exogenous Co-Reactant-Free Electrochemiluminescent Biosensor for Ratiometric Measurement of α-Glucosidase Based on a ZIF-67-Regulated Hydrogen-Bonded Organic Framework.

The development of highly sensitive and selective analytical approaches for monitoring enzymatic activity is critical for disease diagnosis and biomedical research. Herein, we develop an exogenous co-reactant-free electrochemiluminescence (ECL) biosensor for the ratiometric measurement of α-glucosidase (α-Glu) based on a zeolitic imidazolate framework (ZIF-67)-regulated pyrene-based hydrogen-bonded organic framework (HOF-101). Target α-Glu can hydrolyze maltose to α-d-glucose, which can subsequently react with GOx to produce gluconic acid. The resultant gluconic acid can dissolve ZIF-67, leading to the recovery of the HOF-101 cathodic ECL signal and the decrease of the luminol anodic ECL signal. The long-range ordered structure of HOF-101 can speed up charge transfer, resulting in a stable and strong cathodic ECL signal. Moreover, ZIF-67 can not only efficiently quench the ECL signal of HOF-101 due to ECL resonance energy transfer between HOF-101 and ZIF-67 as well as the steric hindrance effect of ZIF-67 but also enhance the anodic ECL emission of luminol in dissolved O2 system because of its ordered and porous crystalline structure and the atomically dispersed Co2+. Notably, HOF-101 possesses a higher ECL efficiency (32.22%) compared with the Ru(bpy)32+ standard. Importantly, this ratiometric ECL biosensor shows high sensitivity (a detection limit of 0.19 U L-1) and a broad linear range (0.2-50 U L-1). This biosensor can efficiently eliminate systematic errors and enhance detection reliability without the involvement of exogenous co-reactants, and it displays good assay performance in human serum samples, holding great promise in biomedical research studies.

Ketogluconate production by Gluconobacter strains: enzymes and biotechnological applications.

Gluconobacter strains perform incomplete oxidation of various sugars and alcohols, employing regio- and stereoselective membrane-bound dehydrogenases oriented toward the periplasmic space. This oxidative fermentation process is utilized industrially. The ketogluconate production pathway, characteristic of these strains, begins with the conversion of d-glucose to d-gluconate, which then diverges and splits into 2 pathways producing 5-keto-d-gluconate and 2-keto-d-gluconate and subsequently 2,5-diketo-d-gluconate. These transformations are facilitated by membrane-bound d-glucose dehydrogenase, glycerol dehydrogenase, d-gluconate dehydrogenase, and 2-keto-d-gluconate dehydrogenase. The variance in end products across Gluconobacter strains stems from the diversity of enzymes and their activities. This review synthesizes biochemical and genetic knowledge with biotechnological applications, highlighting recent advances in metabolic engineering and the development of an efficient production process focusing on enzymes relevant to the ketogluconate production pathway in Gluconobacter strains.

Determination of the median lethal dose of zinc gluconate in mice and safety evaluation.

BACKGROUND: Zinc Gluconate (ZG) is a safe and effective supplement for zinc. However, there is limited research on the optimal dosage for intravenous injection and the safety evaluation of animal models for ZG. This study aims to determine the safe dose range of ZG for intravenous injection in C57BL/6J mice. METHODS: A Dose titration experiment was conducted to determine the LD50 and 95% confidence interval (95%CI) of ZG in mice. Based on the LD50, four sub-lethal doses (SLD) of ZG were evaluated. Following three injections of each SLD and monitoring for seven days, serum zinc levels were measured, and pathological changes in the liver, kidney, and spleen tissues of mice were determined by histological staining. RESULTS: The dose titration experiment determined the LD50 of ZG in mice to be 39.6 mg/kg, with a 95%CI of 31.8-49.3 mg/kg. There was a statistically significant difference in the overall serum zinc levels (H = 36.912, P < 0.001) following SLD administration. Pairwise comparisons showed that the serum zinc levels of the 1/2 LD50 and 3/4 LD50 groups were significantly higher than those of the control group (P < 0.001); the serum zinc level of the 3/4 LD50 group was significantly higher than those of the 1/8 LD50 and 1/4 LD50 groups (P < 0.05). There was a positive correlation between the different SLDs of ZG and the serum zinc levels in mice (rs = 0.973, P < 0.001). H&E staining showed no significant histological abnormalities or lesions in the liver, kidney, and spleen tissues of mice in all experimental groups. CONCLUSION: The appropriate dose range of ZG for intravenous injection in C57BL/6J mice was clarified, providing a reference for future experimental research.

Consistent biosynthesis of D-glycerate from variable mixed substrates.

The use of waste streams and other renewable feedstocks in microbial biosynthesis has long been a goal for metabolic engineers. Microbes can utilize the substrate mixtures found in waste streams, though they are more technically challenging to convert to useful products compared to the single substrates of standard practice. It is difficult to achieve consistent biosynthesis in the face of the temporally changing nature of waste streams. Furthermore, the expression of all the enzymes necessary to convert mixed substrates into a product likely presents significant metabolic burden, which already plagues processes that utilize a single substrate. We developed an approach to utilize mixed feedstocks for production by activating expression of each biosynthetic pathway in the presence of its substrate. This expression control was used for two novel pathways that converted two substrates, galacturonate and gluconate, into a single product, D-glycerate. A production strain harboring both pathway plasmids produced 1.8 ± 0.3 and 1.64 ± 0.09 g L-1 of D-glycerate from galacturonate and gluconate alone, respectively. Fermentations that were fed a mixture of the two substrates, at different ratios, resulted in product titers between 1.48 ± 0.03 and 1.8 ± 0.1 g L-1. All fermentations were fed a total of 10 g L-1 substrate and there was no statistically significant difference in D-glycerate titer from the single or mixed substrate fermentations. We thus demonstrated consistent D-glycerate biosynthesis from single and mixed substrates as an example of robust conversion of complex feedstocks.

Continuous versus intermittent bolus infusion of calcium in preterm infants receiving total parenteral nutrition: a randomized blind clinical trial.

BACKGROUND: Premature neonates need adequate nutritional support to provide sufficient essential nutrients for optimal growth. Calcium (Ca) is one of the important nutrients in parental nutrition support of premature infants. This study aimed to compare the effect of continuous and intermittent bolus infusion of Ca on the incidence of metabolic bone disease (MBD) in preterm infants. METHODS: This randomized double-blind clinical trial was conducted on ninety preterm infants in the NICU of Al-Zahra Hospital in Tabriz, Iran. The preterm infants were randomly allocated to either a continuous infusion group (received 4-5 ml/kg/day of Ca gluconate 10% by PN solution in a 24-h period) or an intermittent bolus administration group (received 1-2 ml/kg/day Ca gluconate 10% three to four times per day). Serial serum levels of Ca, phosphorous, alkaline phosphatase (ALP), vitamin D and parathyroid hormone (PTH) were assessed on the 7th day, 30th day and 45th day of life. RESULTS: A total of 78 infants completed the study. The serum ALP level on the 45th day after birth was 753.28 ± 304.59 IU/L and 988.2 ± 341.3 IU/L in the continuous infusion and intermittent bolus administration groups, respectively (P < 0.05). MBD in preterm infants with ALP levels above 900 IU/L on the 45th day of life was significantly lower in the continuous infusion group than in the intermittent bolus administration group (p < 0.05). The mean serum levels of calcium, phosphorus, vitamin D and PTH in 45-day-old infants were not significantly different between the two groups. CONCLUSION: The MBD in preterm infants who received continuous infusion of Ca was lower than that in preterm infants who received intermittent bolus administration of Ca. TRIAL REGISTRATION: The Iranian Registry of Clinical Trials ( http://www.irct.ir ) with the identification No. IRCT20210913052466N1.

Sustainable cellobionic acid biosynthesis from starch via artificial in vitro synthetic enzymatic biosystem.

Cellobionic acid (CBA), a kind of aldobionic acid, offers potential applications in the fields of pharmaceutical, cosmetic, food, and chemical industry. To tackle the high cost of the substrate cellobiose in CBA production using quinoprotein glucose dehydrogenase, this study developed a coenzyme-free and phosphate-balanced in vitro synthetic enzymatic biosystem (ivSEBS) to enable the sustainable CBA synthesis from cost-effective starch in one-pot via the CBA-synthesis module and gluconic acid-supply module. The metabolic fluxes of this artificial biosystem were strengthened using design-build-test-analysis strategy, which involved exquisite pathway design, meticulous enzyme selection, module validation and integration, and optimization of the key enzyme dosage. Under the optimized conditions, a remarkable concentration of 6.2 g/L CBA was achieved from initial 10 g/L maltodextrin with a starch-to-CBA molar conversion rate of 60 %. Taking into account that the biosystem simultaneously accumulated 3.6 g/L of gluconic acid, the maltodextrin utilization rate was calculated to be 93.3 %. Furthermore, a straightforward scaling-up process was performed to evaluate the industrial potential of this enzymatic biosystem, resulting in a yield of 21.2 g/L CBA from 50 g/L maltodextrin. This study presents an artificial ivSEBS for sustainable production of CBA from inexpensive starch, demonstrating an alternative paradigm for biomanufacturing of other aldobionic acids.