Supplementing Monosodium Glutamate in Sow Diets Enhances Reproductive Performance in Lactating Sows and Improves the Growth of Suckling Piglets.

In most current farm operations, lactating sows need to overcome reproductive and environmental stresses that have resulted in poor sow production performance and piglet growth. Therefore, this study aimed to investigate the effects of in-feed supplementation of monosodium glutamate (MSG) in sows during late gestation lactation in regard to litter performance. The study subjects were 12 multi-parity sows (Landrace × Large White), farrowing sows with an average parity of four (three with three parities, seven with four parities, and two with five parities). They were randomly divided into the following two diet groups: the basal diet as a control (CON) group based on corn and soybean meal; and the basal diet + 2% MSG group. The experimental time ranged from 109 days before delivery to 21 days after delivery. There were six sows in each group, and each sow served as the experimental unit. There were no significant differences (p > 0.05) in body weight (BW), back fat (BF) thickness and estrus interval between sows supplemented with 2% MSG in their diets before and after farrowing and during weaning (p > 0.05). However, MSG-treated sows tended to increase BW loss at farrowing more than the CON group (p = 0.093) but lost less weight during lactation than the CON group (p = 0.019). There were no significant differences in the body condition scores (BCSs) and BF loss of the two groups of sows before and after farrowing and at weaning (p > 0.05). There was no significant difference in the weight of newborn piglets between the two groups of sows (p > 0.05). The weaning weight (p = 0.020) and average daily gain (ADG) (p = 0.045) of suckling piglets were higher in the MSG treated group compared to the CON group. The daily milk production of sows in the MSG treatment group was higher compared to the CON group (p = 0.045). The protein concentration of milk at week 3 (p = 0.060) and fat concentration of milk at week 5 (p = 0.095) of the MSG-supplemented sows tended to increase more than the CON group. In summary, the dietary inclusion of MSG supplementation had a beneficial effect on the late gestating sows and their piglet's growth and milk production. Our research has shown that the addition of 2% MSG in late gestation and lactation diet would be beneficial for both sow and piglet production.

The potential protective effect of Camellia Sinensis in mitigating monosodium glutamate-induced neurotoxicity: biochemical and histological study in male albino rats.

Monosodium glutamate (MSG) is the sodium compound derived from glutamic acid. Excessive daily ingestion of MSG leads to elevated amounts of glutamic acid in the bloodstream, which can be detrimental to brain structures. Camellia sinensis, often known as green tea (GT), is a rich source of essential hexogen antioxidants that are necessary for the body. Thirty-two adult male albino rats were divided into four groups (n = 8). Group 1 served as a control -ve group. Group 2 was given GT (1.5 ml/rat/day). Group 3 was given MSG (600 mg/kg/day). Group 4 was given MSG (600 mg/kg/day) and GT (1.5 ml/rat/day). All treatments were given orally for 28 days. MSG administration resulted in significant neurotoxicity in rats that was revealed by the significant reduction of serum concentration of glutathione peroxidase (GPx) and nitric oxide (NO), and the significant elevation of total antioxidant capacity (TAC) accompanied by the significant reduction of levels of serum monoamines (dopamine, serotonin, and norepinephrine) and histological changes in the hippocampus area CA1, dentate gyrus, and cerebellar cortex and positive immunohistochemical staining of glial fibrillary acidic proteins (GFAP) and calretinin. Administration of GT with MSG counteracted the MSG-mediated oxidative stress by significantly increasing serum concentrations of GPX and NO and significantly decreasing concentrations of TAC. Furthermore, GT significantly increased levels of serum monoamines (dopamine, serotonin, and norepinephrine). Moreover, it ameliorated the histological changes, GFAP, and calretinin immunostaining in brain tissues. It is envisaged that GT will serve as a viable protective choice for the inclusion of the neurotoxicity treatment procedure.

Multifaceted Impacts of Monosodium Glutamate on Testicular Health: Insights into Pyroptosis and Therapeutic Potential of Resveratrol.

BACKGROUND: Monosodium glutamate was considered one of the food additive and flavor enhancer in processed meat and soup that affects testicular tissues, the aim of this research to investigates the impact of monosodium glutamate (MSG) on testicular structure in rats and explores the potential protective effects of resveratrol. MATERIAL AND METHODS: Four experimental groups involved in our study 10 rats of each.: the first group as control group; the second group (Resveratrol group: control rats received 20 mg/kg of resveratrol, via oral gavage); the third group (MSG group: rats received monosodium glutamate (MSG) with a dose 60 mg/kg body weight daily, via gastric tube, and the fourth group (MSG+ Resveratrol group). Serum level of testosterone, FSH, LH, were measured. Testicular tissues were prepared for measurement of oxidative stress markers, and gene expression of NLRP3, Caspase 3, and GSK-3ß. Moreover, paraffin blocks contained testicular tissue used for histological and immunohistochemical examination. Additionally, seminal smear from epididymis were examined. RESULTS: MSG administration adversely affected testosterone production, hormonal levels, and sperm parameters, Histological examination revealed marked testicular degeneration, and oxidative stress assessments indicated elevated level of MDA a lipid peroxidation marker and decrease in SOD, CAT antioxidant enzymes. Moreover, MSG-induced apoptotic and pyroptotic markers and its gene expressions. Importantly. Administration of resveratrol reversed the detrimental effects of MSG, demonstrating its corrective influence on the hypothalamic-pituitary-gonadal axis disruption, improvement of sperm parameters, attenuation of oxidative stress, anti-apoptotic activity, and anti-pyroptotic effects. The expression of Ki-67 as a cell proliferation marker further supported the positive response to spermatogenesis dysfunction upon resveratrol treatment. CONCLUSIONS: This comprehensive exploration sheds light on the protective effect of resveratrol against MSG-induced testicular with exploration of its mechanistic role.

Synergistic effect of combining umami substances enhances perceived saltiness.

Umami substances have the potential to enhance the perception of saltiness and thus reduce sodium intake. Two sensory evaluation experiments were conducted, involving participants tasting salt solutions, and solutions with added umami substances at equal sodium concentrations. Umami substances included sodium glutamate (MSG), disodium inosinate (IMP), and the combination of them which has a synergistic effect and is a closer match to commonly-consumed foods. In Experiment 1, using the two-alternative forced-choice (2-AFC) method by 330 consumers, paired comparisons were conducted at three different sodium concentrations. The combination of MSG and IMP enhanced the perception of saltiness (p < .001 in the difference test), whereas presenting either umami substance in isolation failed to do so (p > .05 in the similarity test). Significant order effects occurred in paired comparisons. In Experiment 2, a two-sip time-intensity (TI) analysis with trained panellists verified these results and found that tasting MSG and IMP either simultaneously or successively enhanced saltiness perception at equal sodium concentrations. These findings indicate that the synergistic effect of umami substances may be the cause of saltiness enhancement, and represents a potential strategy for sodium reduction while satisfying the consumer demand for saltiness perception. Considering the application in food processing and in food pairing, umami substances can potentially be used to help to reduce salt intake in food consumption.

Effect of monosodium glutamate supplementation in diet on fatty acid profiles, genes expression related to lipid metabolism and egg yolk cholesterol in late phase of production in laying hens.

In an experiment with four treatments and five replicates, the effects of adding monosodium glutamate (MSG) to the diet in late phase of egg production was studied on performance, and lipid metabolism in laying hens. Dietary treatments included the control basal diet without MSG and the other treatments adding 0.4%, 0.8% and 1.2% MSG in the control diet respectively. The effect of supplementation of MSG on egg weight, egg production, feed conversion ratio and egg mass was insignificant (p < 0.05). Adding MSG to the diet significantly increased feed intake and blood polyunsaturated fatty acids concentration (p < 0.05). Intake of 0.8% and 1.2% MSG in the diet up regulated the mRNA expression of acetyl-coenzyme A carboxylase, fatty acid synthase and lipoprotein lipase in the abdominal and liver tissues in comparison to the control group. Blood very low-density lipoprotein-cholesterol, triglycerides and cholesterol concentration were increased in treatment fed with a diet containing 0.8% MSG compared to the control group (p < 0.05). The effect of MSG on total egg yolk cholesterol concentration was not significant. In conclusion, the results of the present experiment indicated that adding MSG increased feed intake and blood polyunsaturated fatty acid concentration.

Monosodium glutamate altered renal architecture and modulated expression of NMDA-R, eNOS, and nNOS in normotensive and hypertensive rats.

Monosodium glutamate (MSG) administration has been shown to pronounce hypertension and oxidative status with increased renal blood flow (RBF), however, the precise mechanisms of action have never been demonstrated. This study aimed to investigate the MSG action by studying the alteration in renal architecture and specific protein expression in 2-kidney-1-clip hypertensive comparing to sham operative normotensive rats. The administered doses of MSG were 80, 160, or 320 mg/kg BW daily for 8 weeks. Using routine chemical staining, the congestion of glomerular capillaries, a lesser renal corpuscles and glomeruli size, a widen Bowman capsule's space, an increase in mesangial cell proliferation and mesangial matrix, renal interstitial fibrosis, focal cloudy swelling of renal tubular epithelial cells were observed. Immunological study revealed an increase in the expression of N-methyl-D-aspartate receptor (NMDA-R) and endothelial nitric oxide synthase (eNOS) but a decrease in neuronal NOS (nNOS). It is suggested that MSG may upregulate the NMDA-R levels which responsible for the oxidative stress, glomerular injury, and renal interstitial fibrosis. The NMDA-R may also stimulate eNOS overexpression which resulted in renal microvascular dilatation, a raise in RBF and GFR, and natriuresis and diuresis promotion. Long-term exposure of MSG may trigger adaptation of tubuloglomerular feedback through nNOS downregulation.

Phycoremediation Potential of Salt-Tolerant Microalgal Species: Motion, Metabolic Characteristics, and Their Application for Saline-Alkali Soil Improvement in Eco-Farms.

Microalgae have great potential for remediating salt-affected soil. In this study, the microalgae species Coelastrella sp. SDEC-28, Dunaliella salina SDEC-36, and Spirulina subsalsa FACHB-351 were investigated for their potential to rehabilitate salt-affected soils. Nylon screens with optimal aperture sizes and layer numbers were identified to efficiently intercept and harvest biomass, suggesting a correlation between underflow capability and the tough cell walls, strong motility, and intertwining characteristics of the algae. Our investigations proved the feasibility of incorporating monosodium glutamate residue (MSGR) into soil extracts at dilution ratios of 1/200, 1/2000, and 1/500 to serve as the optimal medium for the three microalgae species, respectively. After one growth period of these three species, the electrical conductivities of the media decreased by 0.21, 1.18, and 1.78 mS/cm, respectively, and the pH remained stable at 7.7, 8.6, and 8.4. The hypotheses that microalgae can remediate soil and return profits have been verified through theoretical calculations, demonstrating the potential of employing specific microalgal strains to enhance soil conditions in eco-farms, thereby broadening the range of crops that can be cultivated, including those that are intolerant to saline-alkali environments.

Metabolic effects of a submaximal dose of pink salt and monosodium glutamate in experimental rats.

Background & objectives: Pink salt and monosodium glutamate (MSG) are two typical food additives used in cooking to enhance flavour. However, excessive use of them has been associated to a variety of metabolic problems, including weight gain and hyperglycemia. The current study aimed to assess the metabolic changes caused by submaximal dosages of MSG and pink salt in experimental rats. Methods: Twenty-four 120-150 g Wister rats of both sexes were divided into three groups: control, pink salt-treated (0.8 g/kg daily for three weeks), and MSG-treated (3.6 g/kg daily for three weeks). The body weight, amount of food and water consumed, and blood glucose levels of animals were measured and recorded as indicators of their metabolic changes. Furthermore, after salt treatments at intervals such as week 1, week 2, and week 3, the survival rate and general toxicity manifestations were determined. The results were statistically analysed using one-way ANOVA, with p < 0.05 being considered significant. Results: The study found that the group given a submaximal dose of MSG gained significantly more weight (p < 0.05), consumed more food and water, and had higher blood glucose levels than the control. Ninety percent of the MSG therapy group survived by the end of the third week, however, they suffered from negative effects like abdominal distention, respiratory problems, ptosis, and subcutaneous swelling. On the other hand, the consumption of food and drink was significantly (p < 0.05) increased upon the administration of pink salt. Only little changes were observed in the body weight, blood sugar levels, and general features (such as subcutaneous swelling, change in bowel colour, and loose stools). Additionally, it was shown that the survival rate remained unchanged, particularly after week 3. Conclusion: According to study findings, MSG may induce metabolic issues, increasing the chance of death. While there was no discernible metabolic aberration linked to pink salt. Further research is required to fully understand the mechanism and consequences of these taste enhancers on the host system before pink salt can be deemed safe.

Immuno-Kachiks formula immunomodulates and ameliorates hepatic damage induced by monosodium glutamate in rats.

The immune system plays a vital role in controlling liver fibrosis and enhancing the pathogenesis of liver inflammation. Monosodium glutamate is a common flavor-enhancement food additive. This study evaluated the immunomodulatory and hepato-curative effects of the Immuno-Kachiks polyherbal formulation against monosodium glutamate-induced immune suppression and hepatic damage in rats. Monosodium glutamate was given orally at a 2000 mg/kg dose to male Wistar rats for three months to induce liver damage and immune suppression. After three months of successful induction, three groups were separately administered orally with Immuno-Kachiks formula at 400, 800, and 1500 mg/kg/day for 28 days. At the end of the treatment period, liver and blood samples were collected for histological and biochemical analysis. The lymphocyte count remained significantly low while the neutrophil count and the neutrophil-to-lymphocyte ratio increased significantly, despite the cessation of monosodium glutamate ingestion for 28 days. The Immuno-Kachiks formula (IKF) significantly increased the lymphocyte count, reduced the neutrophil-to-lymphocyte ratio, and normalized the neutrophil count. Neither monosodium glutamate nor the IKF significantly caused alpha-fetoprotein levels to rise or fall below normal. High doses (800 and 1500 mg/kg) of the Immuno-Kachiks formula significantly raised serum levels of aspartate aminotransferase, alkaline phosphatase, and total bilirubin. 1500 mg/kg of the IKF caused mild liver inflammation. The IKF restored the liver morphologic alterations observed in monosodium glutamate-induced liver damage in rats. The results suggest that the Immuno-Kachiks herbal formulation is a potential curative agent for early-stage liver damage and could restore suppressed adaptive immunity.

A Case of Type I Food Allergy Induced by Monosodium Glutamate.

Monosodium glutamate (MSG), a salt form of a non-essential amino acid, is widely used as a food additive, particularly in Asian cuisines, due to its unique flavor-enhancing qualities. Type I allergic reactions to MSG have not previously been reported. Our patient, a 21-year-old woman, was 14 years old when she first noticed swelling of her tongue (but no oral itching, diarrhea, or abdominal pain) after eating various snack foods. Current skin prick testing elicited a weak positive reaction to MSG. We then performed an oral challenge test during which our patient ingested potato snacks. Subsequent histology showed telangiectasia of the buccal mucosa, interstitial edema in the subepithelial submucosa, and mast cell infiltration. Oral mucosal challenge tests using sodium glutamate confirmed oral swelling in this patient. This report is the first to confirm a case of type 1 allergy to MSG by combining pathology findings with the results of challenge testing.

Hematological changes, oxidative stress assessment, and dysregulation of aquaporin-3 channel, prolactin, and oxytocin receptors in kidneys of lactating Wistar rats treated with monosodium glutamate.

High consumption of locally produced delicacies could expose nursing mothers to high monosodium glutamate (MSG) levels, frequently used as a necessary condiment in low-income countries. Thus, this study evaluated some novel preliminary changes in renal hormonal receptors, the aquaporin-3 channel, oxidative stress markers, and hematological indices induced by monosodium glutamate in lactating rats. Post-parturition, twenty-four (24) lactating Wistar rats were divided into four (4) groups of six rats each (n = 6). Oral administration of distilled water and MSG started three (3) days postpartum as follows: group 1: distilled water (1 ml/kg BW), group 2: MSG (925 mg/kg BW), group 3: MSG (1850 mg/kg BW), and group 4: MSG (3700 mg/kg BW). At the end of the experiment, which lasted fourteen (14) days, animals were sacrificed and samples of blood and tissues were obtained for biochemical analysis. MSG administration significantly (p < 0.05) increased ROS and MDA, with a significant (p < 0.05) decrease in kidney antioxidants. Serum creatinine, total, conjugated, and unconjugated bilirubin significantly (p < 0.05) increased with MSG administration. The prolactin receptor was significantly reduced (p < 0.05), while the oxytocin receptor and aquaporin-3 channel were significantly (p < 0.05) increased in the MSG-administered groups. There were significant (p < 0.05) changes in the hematological indices of the MSG-administered animals. Thus, the findings of this study suggest that high MSG consumption causes hematological alterations and may alter renal function via increased ROS production and dysregulation of the AQP-3 channel, prolactin, and oxytocin receptors in the kidneys of lactating Wistar rats.

Exogenous monosodium glutamate exacerbates lipopolysaccharide-induced neurobehavioral deficits, oxidative damage, neuroinflammation, and cholinergic dysfunction in rat brain.

Extensive experimental evidence points to neuroinflammation and oxidative stress as major pathogenic events that initiate and drive the neurodegenerative process. Monosodium glutamate (MSG) is a widely used food additive in processed foods known for its umami taste-enhancing properties. However, concerns about its potential adverse effects on the brain have been raised. Thus, the present study investigated the impact of MSG on lipopolysaccharide (LPS)-induced neurotoxicity in rat brains. Wistar rats weighing between 180 g and 200 g were randomly allocated into four groups: control (received distilled water), MSG (received 1.5 g/kg/day), LPS (received 250 µg/kg/day), and LPS + MSG (received LPS, 250 µg/kg, and MSG, 1.5 g/kg). LPS was administered intraperitoneally for 7 days while MSG was administered orally for 14 days. Our results showed that MSG exacerbated LPS-induced impairment in locomotor and exploratory activities in rats. Similarly, MSG exacerbated LPS-induced oxidative stress as evidenced by increased levels of malondialdehyde (MDA) with a concomitant decrease in levels of superoxide dismutase (SOD), catalase (CAT), glutathione (GSH), and glutathione-s-transferase (GST) in the brain tissue. In addition, MSG potentiated LPS-induced neuroinflammation, as indicated by increased levels of pro-inflammatory cytokines such as interleukin-6 (IL-6), and tumor necrosis factor-α (TNF-α) as well as myeloperoxidase (MPO) and nitric oxide (NO) in the brain. Moreover, MSG aggravated LPS-induced cholinergic dysfunction, as demonstrated by increased activity of acetylcholinesterase (AChE) in the brain. Further, we found a large number of degenerative neurons widespread in hippocampal CA1, CA3 regions, cerebellum, and cortex according to H&E staining. Taken together, our findings suggest that MSG aggravates LPS-induced neurobehavioral deficits, oxidative stress, neuroinflammation, cholinergic dysfunction, and neurodegeneration in rat brains.

Protective effect of Danshensu against neurotoxicity induced by monosodium glutamate in adult mice and their offspring.

Excessive neuronal excitation by glutamate is a well-established cause of neurotoxicity, leading to severe impairment of brain function. Excitotoxicity is a key factor in numerous neurodegenerative conditions. In this study, we investigated the neuroprotective effects of Danshensu (DSS) against monosodium glutamate (MSG)-induced neurotoxicity in adult mice and their offspring. We randomly divided one hundred 8-week-old Kunming mice (equal number of males and females) into a control group and an experimental group. The experimental group was further subdivided into various treatment groups, including MSG gavage treatment, bwbw DSS treatment group 1 (bwbw DSS treatment group 2, a drug control group, and a normal control group (receiving an equal volume of physiological saline for ten consecutive days). Additionally, another one hundred healthy 8-week-old Kunming mice were similarly divided into groups and treated. These mice were paired randomly (one male and one female) and pregnant females were housed separately to obtain offspring. Subsequently, we conducted histological and behavioral analyses on adult mice and their offspring. MSG treatment induced significant cellular edema and hippocampal damage in both the treated mice and their offspring. However, varying doses of DSS effectively counteracted the neurotoxic effects of MSG, with no adverse impact on brain tissue structure or neural function in either adult mice or their offspring. Behavioral experiments further confirmed that DSS exerted a substantial protective effect against MSG-induced impairment of learning and memory in the treated adult mice and their offspring, in addition to mitigating central nervous system overexcitation and inhibiting exploratory behavior. In conclusion, DSS exerts significant protective effects against MSG-induced neurotoxicity in both adult mice and their offspring.

Quercetin counteracts monosodium glutamate to mitigate immunosuppression in the thymus and spleen via redox-guided cellular signaling.

BACKGROUND: Chronic inflammation brought on by oxidative stress can result in several immunopathologies. Natural compounds with antioxidant characteristics, like quercetin, have shown effectiveness in reducing oxidative damage and regulating the immune response. PURPOSE: The commonly used food additive monosodium glutamate (M) causes immunosuppression by disrupting redox equilibrium and inducing oxidative stress. The goal of this work is to examine the therapeutic potential of quercetin against immunotoxicity brought on by M, revealing the molecular route implicated in such immunopathology by targeting the thymus and spleen, to support the development of future anti-inflammatory and antioxidant therapies. STUDY DESIGN AND METHODS: M-fed rats were employed as an immunotoxicity model and were supplemented with quercetin for four weeks. Hematological and biochemical parameters were measured; H&E staining, immunohistochemistry, flow cytometry, real-time quantitative PCR, and western blotting were performed. RESULTS: Based on the findings, TLR4 was activated by M to cause oxidative stress-mediated inflammation, which was alleviated by the supplementation of quercetin by modulating redox homeostasis to neutralize free radicals and suppress the inflammatory response. To prevent M-induced inflammation, quercetin demonstrated anti-inflammatory functions by blocking NF-kB activation, lowering the production of pro-inflammatory cytokines, and increasing the release of anti-inflammatory cytokines. By normalizing lipid profiles and lowering the potential risk of immunological deficiency caused by M, quercetin also improves lipid metabolism. Additionally, it has shown potential for modifying insulin levels, suggesting a possible function in controlling M-induced alteration in glucose metabolism. The addition of quercetin to M enhanced the immune response by improving immunoglobulin levels and CD4/CD8 expression in the thymus and spleen. Additionally, quercetin inhibited apoptosis by controlling mitochondrial caspase-mediated cellular signaling, suggesting that it may be able to halt cell death in M-fed rats. CONCLUSION: The results of this study first indicate that quercetin, via modulating redox-guided cellular signaling, has a promising role in reducing immune disturbances. This study illuminates the potential of quercetin as a safe, natural remedy for immunopathology caused by M, including thymic hypoplasia and/or splenomegaly, and paves the way for future anti-inflammatory and antioxidant supplements.

Quercetin inhibits NF-kB and JAK/STAT signaling via modulating TLR in thymocytes and splenocytes during MSG-induced immunotoxicity: an in vitro approach.

BACKGROUND: The most widely used food additive monosodium glutamate (MSG) has been linked to immunopathology. Conversely, quercetin (Q), a naturally occurring flavonoid has been demonstrated to have immunomodulatory functions. Therefore, the purpose of the study is to determine if quercetin can mitigate the deleterious effects of MSG on immune cells, and the possible involvement of TLR, if any.  METHODS AND RESULTS: This study was conducted on Q, to determine how it affects the inflammatory response triggered by MSG in primary cultured thymocytes and splenocytes from rats (n = 5). Q shielded cells by augmenting cell survival and decreasing lactate dehydrogenase leakage during MSG treatment. It decreased IL-1ß, IL-6, IL-8, and TNF-α expression and release by hindering NF-kB activation and by inhibiting the JAK/STAT pathway. Moreover, Q prevented NLRP3 activation, lowered IL-1ß production, and promoted an anti-inflammatory response by increasing IL-10 production. Q reduced MSG-induced cellular stress and inflammation by acting as an agonist for PPAR-γ and LXRα, preventing NF-kB activation, and lowering MMP-9 production via increasing TIMP-1. Additionally, Q neutralized free radicals, elevated intracellular antioxidants, and impeded RIPK3, which is involved in inflammation induced by oxidative stress, TNF-α, and TLR agonists in MSG-treated cells. Furthermore, it also modulated TYK2 and the JAK/STAT pathway, which exhibited an anti-inflammatory effect. CONCLUSIONS: MSG exposure is associated with immune cell dysfunction, inflammation, and oxidative stress, and Q modulates TLR to inhibit NF-kB and JAK/STAT pathways, providing therapeutic potential. Further research is warranted to understand Q's downstream effects and explore its potential clinical applications in inflammation.

Unlocking Nature's Toolbox: glutamate-inducible recombinant protein production from the Komagatella phaffii PEPCK promoter.

BACKGROUND: Komagataella phaffii (a.k.a. Pichia pastoris) harbors a glutamate utilization pathway in which synthesis of glutamate dehydrogenase 2 and phosphoenolpyruvate carboxykinase (PEPCK) is induced by glutamate. Glutamate-inducible synthesis of these enzymes is regulated by Rtg1p, a cytosolic, basic helix-loop-helix protein. Here, we report food-grade monosodium glutamate (MSG)-inducible recombinant protein production from K. phaffii PEPCK promoter (PPEPCK) using green fluorescent protein (GFP) and receptor binding domain of SARS-CoV-2 virus (RBD) as model proteins. RESULTS: PPEPCK-RBD/GFP expression cassette was integrated at two different sites in the genome to improve recombinant protein yield from PPEPCK. The traditional, methanol-inducible alcohol oxidase 1 promoter (PAOX1) was used as the benchmark. Initial studies carried out with MSG as the inducer resulted in low recombinant protein yield. A new strategy employing MSG/ethanol mixed feeding improved biomass generation as well as recombinant protein yield. Cell density of 100-120 A600 units/ml was achieved after 72 h of induction in shake flask cultivations, resulting in recombinant protein yield from PPEPCK that is comparable or even higher than that from PAOX1. CONCLUSIONS: We have designed an induction medium for recombinant protein production from K. phaffii PPEPCK in shake flask cultivations. It consists of 1.0% yeast extract, 2.0% peptone, 0.17% yeast nitrogen base with ammonium sulfate, 100 mM potassium phosphate (pH 6.0), 0.4 mg/L biotin, 2.0% MSG, and 2% ethanol. Substitution of ammonium sulphate with 0.5% urea is optional. Carbon source was replenished every 24 h during 72 h induction period. Under these conditions, GFP and RBD yields from PPEPCK equaled and even surpassed those from PAOX1. Compared to the traditional methanol-inducible expression system, the inducers of glutamate-inducible expression system are non-toxic and their metabolism does not generate toxic metabolites such as formaldehyde and hydrogen peroxide. This study sets the stage for MSG-inducible, industrial scale recombinant protein production from K. phaffii PPEPCK in bioreactors.

Unraveling the effects of drying techniques on chaya leaves: Metabolomics analysis of nonvolatile and volatile metabolites, umami taste, and antioxidant capacity.

Chaya (Cnidoscolus chayamansa) leaves are known for their strong umami taste and widespread use as a dried seasoning. This study aimed to assess the impact of different drying methods [freeze drying (FD), vacuum drying, oven drying at 50 °C and 120 °C (OD120) and pan roasting (PR)] on the metabolome using mass spectrometry, umami intensity, and antioxidant properties of chaya leaves. The predominant volatile compound among all samples, 3-methylbutanal, exhibited the highest relative odor activity value (rOAV), imparting a malt-like odor, while hexanal (green grass-like odor) and 2-methylbutanal (coffee-like odor) are the second highest rOAV in the FD and PR samples, respectively. OD120 and PR samples possessed the highest levels of umami-tasting amino acids and 5'-ribonucleotides as well as the most intense umami taste, whereas FD samples exhibited the highest antioxidant capacity. These findings enhance our understanding of the aroma characteristics, umami taste, and antioxidant potential of processed chaya leaves.

Disruptive consequences of monosodium glutamate on male reproductive function: A review.

Monosodium glutamate (MSG) is one of the most extensively used flavour enhancers worldwide. Although it is widely regarded as a safe food additive with no recommended daily dosage, its over-consumption has been associated with notably pathophysiological events in various tissues and organs of the body. Previous studies have reported of the neuro- cardio- and hepato- toxic effects of its excessive exposure. Moreover, the food additive instigates metabolic dysfunction. It has been established that MSG damages male reproductive accessory organs like prostate glands and epididymis. In addition, it impairs serum enzymatic activities and serum levels of testosterone, gonadotropin-releasing hormone, luteinizing hormone and cholesterol. Reduced sperm count, sperm motility, sperm morphology, and sperm viability, imbalances in male reproductive hormones, alongside alteration in the histoarchitecture of the testes and other male reproductive tissues have also been connected with excessive exposure to MSG. Literature reports affirm the link between the over-consumption of MSG and reproductive organ weight and male sexual behaviour. This review article addresses the multi-systemic effects of exposure to MSG and the possible mechanism of action of the compound with a focus on the negative implications of the food additive on male reproductive functions and the possible role of natural antioxidants in male reproductive functions. carefully selected keywords were used during the literature search to gather credible and up-to-date information about the subject matter.

Investigating the effect of exposure to monosodium glutamate during pregnancy on development of autism in male rat offspring.

In present study, we investigated the relationship between the pregnancy exposure to monosodium glutamate (MSG) and autism development in male offspring of rats. Pregnant Wistar rats were allocated into five groups. The first group was control group that pregnant animals received normal saline orally from day 1-18 of pregnancy. Group 2, 3 and 4 pregnant rats received different doses (1.5, 5 and 10 g/kg) of MSG by the same way respectively. Group 5 received 500 mg/kg of Valproic acid (VPA) on the 12.5th day of pregnancy. Different behavioral tests including marble burying, self-grooming, and Barnes maze test were performed on offspring. The levels of glutamate and GSH markers were also measured. The results showed that MSG similar to VPA led to induction of autistic anxiety and repetitive behaviors. It could also deteriorate the spatial memory. Besides we found that behavioral symptoms potentiated with increasing the MSG dosage. Similarly, we had an increase in glutamate and a reduction in GSH levels in offspring. Findings indicated that MSG was able to induce autism in offspring of rats in a dose-dependent way. This effect could be through increasing of glutamate and reduction of GSH. Consequently, MSG should be avoided during pregnancy.

Monosodium Glutamate Even at Low Dose May Affect Oxidative Stress, Inflammation and Neurodegeneration in Rats.

Monosodium glutamate (MSG) is a widely used flavour enhancer. A daily intake of MSG at high dosage (2000-4000 mg/kg body weight) is reported to be toxic to humans and experimental animals. The present study aims to investigate the toxic effect of oral administration of MSG at low concentrations (30 and 100 mg/kg body weight) by evaluating biochemical parameters of oxidative stress and inflammation in blood; expression of neuroinflammatory gene and histopathological changes in brain on male Wistar rats. The administration of MSG significantly increases serum level of fasting glucose, insulin, triglycerides, total cholesterol, low-density lipoprotein and decrease level of high-density lipoprotein. Significant low level of FRAP, GSH, SOD, CAT and higher level of MDA, PCO, AOPP, PMRS, NO, CRP, IL-6, TNF-α confirms substantial oxidative stress followed by inflammation after 100 mg MSG treatment. RT-PCR figure shows significant expression of neuroinflammatory gene IL-6 and TNF-α and histopathological examination revealed severe neurodegeneration in hippocampus (CA1 and CA3) and cerebral cortex region of brain at 100 mg MSG treatment. Our result provides evidence that MSG administration at 30 mg does not impose toxicity, however at 100 mg/kg body weight, which is considered a low dose, there is significant toxic effects and may be detrimental to health.