Zinc and L-Ascorbic Acid Dietary Supplementation Affected Antioxidant Status, Heat Shock Protein 70, and Some Immunoglobulins in Japanese Quail Under Heat Stress Conditions

This study assessed the impact of the dietary inclusion of L-ascorbic acid and organic zinc (Availa-Zn) on heat-stressed Japanese quails. Growth performance, antioxidant status, immune status, heat shock protein 70 (HSP70), and some blood biochemical parameters were assessed. One-day-old, unsexed Japanese quail chicks (n = 240) were randomly allocated into 4 dietary treatments (6 replicates per treatment; 10 birds per replicate). Birds were fed a basal corn-soybean meal diet (control treatment) with different supplemental levels of L-ascorbic acid and/or Availa-Zn (200 mg L-ascorbic acid/kg diet, 62 mg Availa-Zn/kg diet, and 200 mg L-ascorbic acid + 62 mg Availa-Zn/kg diet) from July to August 2020 for 35 days. The average minimum and maximum ambient temperatures varied from 85.4 to 98.8 °F, and the relative humidity was between 69 and 74%. Supplemented L-ascorbic acid and Availa-Zn, either as separate supplements or as combined supplements, increased bird growth performance, blood hemoglobin, thyroid hormones, total protein, globulin, total antioxidant capacity, HSP70, catalase, superoxide dismutase enzyme activity, and immunoglobulin A and G (P < 0.05), while heterophil/lymphocytes decreased (P < 0.01) during the entire rearing period (1-35 days). Most of the assessed parameters showed stronger responses when L-ascorbic acid and Availa-Zn were added together, which may suggest a synergistic effect. In conclusion, the combined supplementation of L-ascorbic acid and Availa-Zn at 200 and 62 mg/kg, respectively, could be considered an efficient dietary supplement to enhance Japanese quail growth performance, antioxidant capacity, immune status, and general health under heat stress conditions.

Enhanced 2-keto-L-gulonic acid production by a mixed culture of Ketogulonicigenium vulgare and Bacillus megaterium using three-stage temperature control strategy

As a key precursor of vitamin C, 2-keto-L-gulonic acid (2-KLG) was mainly produced from L-sorbose by mixed fermentation of Ketogulonicigenium vulgare and a helper strain (Bacillus spp.) with a low conversion rate for decades. The aim of this study was to enhance the 2-KLG production by co-culturing K. vulgare and Bacillus megaterium using three-stage temperature control (TSTC) strategy. By investigating the temperature effect on the 2-KLG fermentation, the optimum temperatures for the growths of K. vulgare and B. megaterium were 32 °C and 29 °C, respectively, while the optimum temperature for 2-KLG production was 35 °C. We developed a TSTC process: the temperature was kept at 32 °C during the first 16 h of fermentation, then decreased to 29 °C for the following 14 h, and maintained at 35 °C to the end of fermentation. By using this new process, the productivity and yield of 2-KLG from L-sorbose were obtained at 2.19 ± 0.19 g/L/h and 92.91 ± 1.02 g/L in 20-L fermentors for 5 batches, respectively, which were 22.35% and 6.02% higher than that of the control treatment (the single temperature of 29 °C). The increased cell density of K. vulgare during the exponential phase and the enhanced SDH activity (increased by 25.18% at 36 h, 17.14% at 44 h) in the production stage might be the reasons for enhanced 2-KLG conversion rate and yield. Our results demonstrated the feasibility of the TSTC strategy for 2-KLG production.

An amperometric biosensor based on poly(L-aspartic acid), nanodiamond particles, carbon nanofiber, and ascorbate oxidase-modified glassy carbon electrode for the determination of L-ascorbic acid

An amperometric L-ascorbic acid biosensor utilizing ascorbate oxidase (AOx) immobilized onto poly(L-aspartic acid) (P(L-Asp)) film was fabricated on carbon nanofiber (CNF) and nanodiamond particle (ND)-modified glassy carbon electrode (GCE). Effects of AOx, ND, and CNF amounts were investigated by monitoring the response currents of the biosensor at different amounts of AOx, ND, and CNF. The electropolymerization step of L-aspartic acid on CNF-ND/GCE surface was also optimized. Scanning electron microscopy (SEM), cyclic voltammetry (CV), and electrochemical impedance spectroscopy (EIS) techniques were used to enlighten the modification steps of the biosensor. The effects of pH and applied potential were studied in detail to achieve the best analytical performance. Under optimized experimental conditions, the AOx/P(L-Asp)/ND-CNF/GCE biosensor showed a linear response to L-ascorbic acid in the range of 2.0 × 10^-7-1.8 × 10^-3 M with a detection limit of 1.0 × 10^-7 M and sensitivity of 105.0 μAmM^-1 cm^-2. The novel biosensing platform showed good reproducibility and selectivity. The strong interaction between AOx and the P(L-Asp)/ND-CNF matrix was revealed by the high repeatability (3.4%) and good operational stability. The AOx/P(L-Asp)/ND-CNF/GCE biosensor was successfully applied to the determination of L-ascorbic acid in vitamin C effervescent tablet and pharmaceutical powder containing ascorbic acid with good results, which makes it a promising approach for quantification of L-ascorbic acid. Graphical abstract.

A novel mıcrobıal bıosensor system based on C. tropicalis yeast cells for selectıve determınatıon of L-Ascorbıc acid

In this study, a novel microbial biosensor was developed for the selective determination of L-Ascorbic acid. In the construction of the microbial biosensor, lyophilized Candida tropicalis yeast cells were immobilized with o-aminophenol by forming a film layer on a platinum electrode surface using electropolymerization. L-Ascorbic acid was quantified on the basis of both amperometric and differential pulse voltammetry (DPV) methods using the biosensor. The measurements were made at +0.24 V (vs Ag/AgCl) for amperometric studies and between 0.0 V and +0.7 V for DPV studies based on the oxidation of L-Ascorbic acid to dehydro-L-Ascorbic acid by ascorbate oxidase which takes place within the catabolic metabolic pathway of C. tropicalis yeast cells. According to the results obtained from the two methods, the response of the biosensor depends linearly on L-Ascorbic acid concentration between 100 and 1500 μM. The detection limit was 62 μM and 59 μM for amperometric and DPV measurements, respectively. The response time of the microbial biosensor was 14 s and 5 s for DPV and amperometric measurements, respectively. In the optimization studies of the biosensor, some parameters such as the optimum amount of the microorganism, o-aminophenol concentration, pH and temperature were determined. For the characterization of the biosensor, reproducibility, storage stability and the effect of interferences were determined.

Electrochemical sensing of L-ascorbic acid by using a glassy carbon electrode modified with a molybdophosphate film

Electrochemical sensing of L-ascorbic acid (AA) is reported based on the use of a redox-active molybdophosphate film on a glassy carbon electrode (GCE). Molybdophosphate is formed by reacting hydroxyapatite nanoparticles with sodium molybdate. The modified GCE can be utilized for detection of AA, typically at a working potential of 0.4 V (vs. Ag/AgCl). The GCE has a decreased overpotential and enhanced sensitivity (219 μA·mM^-1·cm^-2). Response is linear in the 1 μM to 1.5 mM AA concentration range, and the limit of detection is 4 nM. The selectivity of this sensor makes it a useful tool for accurate determination of AA in practical samples as shown for a vitamin C tablet and for spiked beverages. Graphical abstract An electrochemical sensing platform is reported that is based on the use of a redox-active molybdophosphate film that was formed via reacting hydroxyapatite nanoparticles (HAP-NPs) with sodium molybdate. Graphical abstract contains poor quality of text inside the artwork. Please do not re-use the file that we have rejected or attempt to increase its resolution and re-save. It is originally poor, therefore, increasing the resolution will not solve the quality problem. We suggest that you provide us the original format. We prefer replacement figures containing vector/editable objects rather than embedded images. Preferred file formats are eps, ai, tiff and pdf.We have uploaded the graphical abstract as PDF format.

L-Ascorbic Acid Protected Against Extrinsic and Intrinsic Apoptosis Induced by Cobalt Nanoparticles Through ROS Attenuation

Currently, tissue damage induced by cobalt nanoparticles (CoNPs) and cobalt ions (Co²⁺) are the most serious syndrome in the patients with metal-on-metal hip prostheses. Therefore, an urgent need exists for the identification of the mechanisms and the development of therapeutic strategies to limit it. The purpose of this study was to explore the mechanism of this damage and to demonstrate if L-ascorbic acid (L-AA) could protect against the cell toxicities induced by CoNPs and Co²⁺ in vitro. With CoNPs and Co²⁺ treatment, cell viability was significantly decreased; the ROS (reactive oxygen species) level in mitochondria was dramatically increased in CoNPs treated cells, but cobalt ions could barely induce the ROS. Consistently, the level of cell apoptosis was increased with the upregulation of pro-apoptotic factors (caspases 8, 9, and 3, and Bax) and the downregulation of anti-apoptotic factor Bcl-2. Besides that, the levels of cytochrome c and AIF were increased and released from mitochondria into the cytoplasm. After the cells were pretreated with L-AA, the cell viability decreased by CoNPs was reversed and the ROS induced by CoNPs was suppressed. The level of cell apoptosis induced by CoNPs was decreased as well. But it could not reverse the effects induced by Co²⁺. These studies demonstrated that CoNPs induce extrinsic and intrinsic apoptotic pathways via generation of ROS, and L-AA could prevent the cytotoxicity by reducing the level of ROS. While Co²⁺ may induce cytotoxicity through other signals, it could not be protected by L-AA treatment.