Arg Concentrations Research Articles

An Evaluation of the Arginine Requirements of Broiler Chickens and the Potential Arginine and Energy-Saving Effects of Guanidinoacetic Acid.

Two 35-day trials were conducted to determine the arginine (Arg) requirement of broiler chickens and the Arg and energy-sparing effects of guanidinoacetic acid (GAA). In experiment 1, a low-Arg diet (basal diet) was supplemented with increasing levels (0.06-0.61%) of L-Arg or GAA. In experiment 2, a diet meeting the energy and amino acid requirements of broiler chickens served as the positive control (PC). Two negative control (NC) groups were assigned by reducing either 50 (NC1) or 100 (NC2) kcal nitrogen-corrected metabolizable energy. Test groups were supplemented with 0.06% GAA for NC1 and 0.12% GAA for NC2 to compensate for the lower energy in the feed. The low dietary Arg concentration (starter: 1.02%, grower: 0.88%, finisher: 0.75%) significantly reduced overall performance (p < 0.05). Supplementation of either L-Arg or GAA with a low-Arg diet both alleviated the lower performance (p < 0.05). However, more GAA was needed to provide the same level of growth attained with L-Arg at an equivalency rate of 1 GAA to 0.57 Arg. Reduction of dietary energy by 50 and 100 kcal did not significantly influence the performance of birds at all stages of growth. Moreover, no effect of GAA supplementation at 0.06% or 0.12% was observed.

Arginine combination with fluoride and calcium glycerophosphate: effects of concentration and on biofilm fluid.

Aim: To study the influence of varying concentrations of arginine (Arg) combined with fluoride (F) and/or calcium glycerophosphate (CaGP) on biofilms.Materials & methods: Biofilms were analyzed for acidogenicity, microbial viability and Ca, F and inorganic phosphorus (P) concentrations.Results: For total bacteria, the lowest viability was found in F-containing groups, regardless of the arginine concentrations and presence of CaGP. For aciduric bacteria, no significant differences were found among arginine concentrations in the presence of F. For MS, arginine concentrations did not influence MS viability in the presence of fluoride and CaGP only decreased viability at 3.2% Arg concentration. The arginine-treated groups showed the lowest acidogenicity. For ion concentrations in biofilms, CaGP showed the highest values for P; Arg+F for F; and CaGP/Arg+CaGP for Ca.Conclusion: Different concentrations of arginine did not affect the microbial viability or acidogenicity of biofilms. Moreover, 0.8% Arg did not increase ion concentration in biofilm fluid.

Evaluation of the Dietary Arginine Supplementation on Yellow Catfish: From a Low-Temperature Farming Perspective.

The yellow catfish is an economically significant freshwater fish with increasing importance in aquaculture. However, the low temperature environments prevalent in certain regions pose challenges to its growth, development, and overall health. This study aimed to explore the impact of dietary arginine (Arg) addition on the growth, digestive capacity, and intestinal antioxidant response in fish under low temperature acclimation (18 °C). Total 720 fish were randomly distributed into six groups, each containing 120 fish. Over the course of eight weeks, each group was fed with diets about varying Arg concentrations (1.79-3.26 g/kg). The results indicated that Arg supplementation resulted in an increase in specific growth rate (SGR), feed intake (FI), feed efficiency (FE), as well as pancreatic enzyme activities in both pancreas and intestine. Conversely, malondialdehyde (MDA) and protein carbonyl (PC) contents initially decreased but increased with higher Arg concentrations. Glutathione peroxidase 1a (GPX1a) showed a positive correlation with nuclear factor-erythroid 2-related factor-2 (Nrf2), showing its role in antioxidative capacity. Furthermore, this study revealed that Arg significantly enhanced the activities of anti-superoxide anion, anti-hydroxyl radical, and anti-oxidative enzymes, along with the relative mRNA abundance of Copper-Zinc superoxide dismutase (CuZnSOD), catalase, GPX1a, glutamate-cysteine ligase catalytic subunit (GCLC), and Nrf2 in the intestine. It was determined that yellow catfish weighing between 61.0 g and 89.0 g require an intake of 26.8 g of Arg per kilogram of diet based on polynomial regression analysis of specific growth rate (SGR), which is equivalent to 37.0 g of dietary protein, under sub-low temperature conditions of 18 °C.

Profiling the L-arginine/arginase 1 metabolism in early and advanced atherosclerosis

Abstract Background Atherosclerosis is a chronic inflammatory disease and the primary underlying cause of cardiovascular disease (CVD). Recently, intracellular metabolic pathways have been identified as master switches of immune cell function and thus seem promising targets for therapeutic interventions aimed at lowering inflammation and thereby atherogenesis. Decades of research have demonstrated the importance of the amino acid (AA) L-arginine (Arg) in CVD. Although most research has focused on endothelium-dependent effects of Arg by the nitric oxide synthase (NOS), Arg metabolism - mainly through its metabolizing enzyme arginase 1 (Arg1) - has also been shown to regulate immune cell responses independent of its endothelial functions. Despite these findings, the cell-specific contribution of Arg/Arg1 metabolism on atherogenesis is still largely unknown. Purpose Profiling the Arg metabolism in endothelial and immune cells to identify cell-specific changes during athero-progression. Methods To investigate Arg metabolism in atherogenesis, we fed apolipoprotein E deficient (Apoe-­/­-) mice a Western diet (WD) for 6 and 12 weeks. Chow diet-fed aged-matched Apoe-­/-­ mice were used as littermate controls and C57BL/6 mice as steady-state controls. Systemic and local Arg concentrations were measured by mass-spectrometry. Arg metabolism in organs was studied by qPCR. Arg1 expression in atherosclerotic lesions was examined by immunohistochemistry (IHC). To assess cell-specific expression of Arg-related enzymes, aortic leukocytes from WD-fed Apoe-­/-­ mice were subjected to CITE-seq analysis. The role of T cell Arg1 was determined by nor-NOHA inhibition in Jurkat cells. Results AA measurements showed that systemic Arg was reduced in early and advanced atherogenesis (p&amp;lt;0.02), and splenic Arg was reduced in advanced atherogenesis (p=0.006) compared with steady state. In advanced atherosclerosis, Arg1 was decreased in the liver but increased in the spleen and aorta, whereas Nos2 was increased in the liver and aorta compared with steady state. To identify the cell types driving these local changes, we performed IHC on atherosclerotic lesions. Arg1+ lesional macrophages accumulated in advanced compared to early lesions (p=0.03), whereas Arg1+ endothelial cells tended to decrease (p=0.2). Surprisingly, we also found an accumulation of Arg1+ CD4+ T cells in lesions and a further upward trend with athero-progression. CITE-seq confirmed a constitutive expression of Arg1 in lymphoid clusters. In vitro experiments with Jurkat cells showed that arginase inhibition suppressed T cell proliferation and promoted apoptosis and migration (all p&amp;lt;0.0001). Conclusion Our data indicate that Arg metabolism is strongly regulated during athero-progression and suggest a so far unknown role of T cell-intrinsic Arg/Arg1 metabolism in the disease. Murine atherosclerosis studies are now being performed to decipher the cell-specific contribution of Arg/Arg1 metabolism in atherosclerosis.

The regulatory effects of arginine on ovary development in the Chinese mitten crab Eriocheir sinensis

This study aimed to investigate the effects of arginine (Arg) on the vitellogenesis and ovarian maturation of Chinese mitten crab. Six isonitrogenous and isolipidic diets (1.83, 2.52, 3.26, 3.96, 4.81 and 5.52 % Arg) were fed to adult female Chinese mitten crab (60.05 ± 4.33 g). The feeding period lasted for eleven weeks. The results showed that gonadosomatic index of crabs increased with increasing dietary Arg concentrations from 1.83 % to 2.52 % and significantly decreased from 2.52 % to 5.52 %. The quadratic regression analysis based on gonadosomatic index estimated that the optimal Arg requirement for adult female crabs was 2.60 %. Dietary supplementation with 2.52 % Arg significantly increased the crude protein concentration in the ovary. A dose of 2.52 % Arg significantly decreased the vitellogenesis-inhibiting hormone (VIH) content in the hemolymph. Arg (2.52 %) significantly upregulated the Vg and protein kinase A (PKA) gene expressions and increased the cyclic adenosine monophosphate (cAMP) concentration in the hepatopancreas. Moreover, dietary supplementation with 2.52 % Arg significantly decreased the cyclic guanosine monophosphate (cGMP) concentration and downregulated protein kinase G (PKG) and p38 mitogen-activated protein kinase (p38 MAPK) gene expression. Arg at 2.52 % significantly increased hemolymph Vg content and the gene expression of the vitellogenin receptor (VgR). In conclusion, Arg at 2.52 % improved vitellogenesis and ovarian maturation by reducing the VIH content and regulating Vg expression via the cGMP/cAMP pathway.

Improving Water-Based Drilling Mud Performance Using Biopolymer Gum: Integrating Experimental and Machine Learning Techniques.

Drilling through shale formations can be expensive and time-consuming due to the instability of the wellbore. Further, there is a need to develop inhibitors that are environmentally friendly. Our study discovered a cost-effective solution to this problem using Gum Arabic (ArG). We evaluated the inhibition potential of an ArG clay swelling inhibitor and fluid loss controller in water-based mud (WBM) by conducting a linear swelling test, capillary suction timer test, and zeta potential, fluid loss, and rheology tests. Our results displayed a significant reduction in linear swelling of bentonite clay (Na-Ben) by up to 36.1% at a concentration of 1.0 wt. % ArG. The capillary suction timer (CST) showed that capillary suction time also increased with the increase in the concentration of ArG, which indicates the fluid-loss-controlling potential of ArG. Adding ArG to the drilling mud prominently decreased fluid loss by up to 50%. Further, ArG reduced the shear stresses of the base mud, showing its inhibition and friction-reducing effect. These findings suggest that ArG is a strong candidate for an alternate green swelling inhibitor and fluid loss controller in WBM. Introducing this new green additive could significantly reduce non-productive time and costs associated with wellbore instability while drilling. Further, a dynamic linear swelling model, based on machine learning (ML), was created to forecast the linear swelling capacity of clay samples treated with ArG. The ML model proposed demonstrates exceptional accuracy (R2 score = 0.998 on testing) in predicting the swelling properties of ArG in drilling mud.

3D printed emulsion based on arginine-myofibrillar protein

The feasibility of preparing high internal phase Pickering emulsions (HIPPEs) from arginine (Arg) and tilapia myofibrillar protein (MP) complex particles for 3D printing was investigated. The characterization of Arg-MP solutions showed that the Arg-MP complexes had excellent emulsification potential. HIPPE stabilized by Arg-MP had a strong self-supporting and stable gel structure. Therefore, HIPPE stabilized by Arg-MP showed excellent stability. Furthermore, the viscoelasticity and thixotropic recovery of the Arg-MP-stabilized HIPPEs increased with increasing Arg concentrations. This made them suitable for 3D printing. Notably, the Arg-MP stabilized HIPPEs exhibited the best printing precision shape, resolution, and clear contours in 3D printing at an Arg concentration of 0.5 wt%. Our results provide a valuable source of food-grade materials for 3D printing inks and demonstrate a promising strategy for deep processing of tilapia myofibrillar protein.

Removal efficiency of antibiotic residues, antibiotic resistant bacteria, and genes across parallel secondary settling tank and membrane bioreactor treatment trains in a water reclamation plant

Antimicrobial resistance is recognized as a potent threat to human health. Wastewater treatment facilities are viewed as hotspots for the spread of antimicrobial resistance. This study provides comprehensive data on the occurrences of 3 different antibiotic resistant opportunistic pathogens (with resistance to up to 5 antibiotics), 13 antibiotic resistant genes and intI1, and 22 different antimicrobial residues in a large water reclamation plant (176 million gallons per day) that runs a conventional Modified Ludzack-Ettinger (MLE) reactor followed by a secondary settling tank (SST) and membrane bioreactor (MBR) in parallel.All the antibiotic resistant bacteria and most of the antibiotic resistance genes were present in the raw influent, ranging from 2.5 × 102–3.7 × 106 CFU/mL and 1.2× 10−1–6.5 × 1010 GCN/mL, respectively. MBR outperformed the SST system in terms of ARB removal as the ARB targets were largely undetected in MBR effluent, with log removals ranging from 2.7 to 6.8, while SST only had log removals ranging from 0.27 to 4.6. Most of the ARG concentrations were found to have significantly higher in SST effluent than MBR permeate, and MBR had significantly higher removal efficiency for most targets (p < 0.05) except for sul1, sul2, blaOXA48, intI1 and 16S rRNA genes (p > 0.05). As for the antibiotic residues (AR), there was no significant removal from the start to the end of the treatment process, although MBR had higher removal efficiencies for azithromycin, chloramphenicol, erythromycin, erythromycin-H2O, lincomycin, sulfamethoxazole and triclosan, compared to the SST system. In conclusion, MBR outperformed SST in terms of ARB and ARGs removal. However low removal efficiencies of most AR targets were apparent.

Synthesis of novel fluorescence probes and their application in the enantioselective recognition of arginine.

Arginine (Arg) plays a crucial and multifaceted role in various biological processes, encompassing cell division, wound healing, immune system modulation, and plant signaling. This study introduced a pair of novel chiral fluorescent probes, (R)-5 and (S)-5, constructed upon the BINOL framework, which exhibited enantiomeric selectivity and sensitivity to d-Arg/l-Arg in fluorescence experiments. These probes offered a simple, rapid, low-cost, and highly selective method for detecting Arg enantiomers, thereby providing a highly sensitive approach for their qualitative and quantitative analysis. The enantioselective fluorescence enhancement ratios {ef = [(I1 - I0)/(I2 - I0) = ΔI1/ΔI2]} of (R)-5 and (S)-5 to Arg were 1694 and 5163, respectively. Moreover, the probes demonstrated the capability to detect the concentration of d-Arg and l-Arg with a limit of detection of 4.84 × 10-7 M and 3.35 × 10-7 M, respectively, as well as determine the enantiomeric excess. These probes exhibited high chemical selectivity and enantioselectivity, enabling the identification of different configurations of Arg, quantification of Arg concentrations, and determination of the enantiomeric composition of Arg. This study provides valuable insights for the development of sensitive and selective chiral molecular detection methods, significantly advancing our comprehension of the relationship between Arg concentration and probe fluorescence response.

Effects of increasing dietary arginine supply during the three first weeks after weaning on pig growth performance, plasma amino acid concentrations, and health status.

A total of 425 weaned pigs (Exp. 1: 225 pigs [5.8 ± 0.9 kg]; Exp. 2: 200 pigs [6.1 ± 1.2 kg]) were used to determine the optimal dietary standardized ileal digestible (SID) arginine (Arg) level in early nursery diets based on growth and health responses. The basal diet in Exp.1 was formulated to meet SID Arg recommendation (0.66%; NRC, 2012) and in Exp. 2, SID Arg was set to simulate current industry practices for feeding nursery pigs (1.15 %). Basal diets were supplemented with 0.3%, 0.6%, 0.9%, and 1.2% of l-arginine to provide five levels of dietary SID Arg. Experimental diets were fed during phases I (days 0 to 7) and II (days 8 to 21) with common diets until market. Feed disappearance and body weight (BW) were measured on days 7, 14, 21, and 43. Final BW was recorded at first removal of pigs for market. Pen fecal score was assigned daily from days 0 to 21. Plasma immunoglobulin A (IgA) was determined on days 0, 7, and 14 and amino acids (AAs) concentration and plasma urea nitrogen (PUN) on days 0 and 14. Orthogonal polynomial contrasts were used to determine the linear and quadratic effects of dietary Arg. Optimal SID Arg was determined by fitting the data with piecewise regression, using growth performance as the primary response variable. In Exp. 1, dietary Arg linearly increased (P < 0.1) BW, average daily gain (ADG), and gain to feed ratio (G:F) ratio on day 21, as well as reduced (χ2 = 0.004) the percentage of pigs that lost weight (PLW) in week 1 by 29%. Dietary Arg resulted in linear improvement (P = 0.082) of ADG for the overall nursery period and quadratic improvement (P < 0.1) of final BW at marketing. In Exp. 2, dietary Arg linearly increased (P < 0.05) ADG and average daily feed intake (ADFI) in week 1, BW and ADFI (P < 0.1) on day 14, as well as reduced (χ2 ≤ 0.001) PLW in week 1. From days 0 to 21, G:F was improved quadratically (P < 0.1). Dietary Arg linearly increased (P < 0.1) ADG and BW on day 43. Dietary Arg supplementation decreased the incidence (χ2 < 0.05) of soft and watery feces during the first weeks after weaning and lower concentration of plasma IgA on days 7 and 14. Dietary Arg linearly and/or quadratically influenced plasma AA concentrations (P < 0.05), including an increase in Arg, Leu, Phe, Val, citrulline, ornithine, and PUN concentrations. Overall, weaned pigs exhibit optimal nursery growth performance and health when provided with dietary SID Arg ranging from 1.5% to 1.9%. This dietary range contributes to a reduction in the occurrence of fall-back pigs and improvements in final BW at marketing.

PSI-29 Effects of Dietary Intake on Amino Acid Composition of Histotroph (Uterine Luminal fluid) in Nonpregnant Cows: Implications for Pregnancy

Abstract When the developing embryo enters the uterus, before the placenta develops, the embryo receives nourishment from endometrially derived histotroph produced by the uterine glands that remain functional throughout gestation. Throughout pregnancy, this histotroph remains necessary for proper embryonic development. Maternal nutrition may affect histotroph composition resulting in altered embryo development. The objectives were to determine the effects of dietary intake on histotroph amino acid (AA) concentrations. Eighteen multiparous nonpregnant cows (initial BW = 597 kg) were housed at the North Dakota State University Animal Nutrition and Physiology Center (n = 6 cows/pen). Cows were individually fed a TMR once daily via a Calan feeding system and had ad libitum access to fresh water. Cows were randomly assigned to 1 of 2 treatments (n = 9/treatment): dietary intake designed to maintain body weight (CON) or dietary intake designed to lose body weight at a moderate rate (-0.7 kg/d; NEG), for 63 days. Slaughter group 1 contained 4 CON and 5 NEG cows, and group 2 contained 5 CON and 4 NEG cows. Cows were estrus-synchronized with the Co-Synch + CIDR protocol to ensure a common day of the estrous cycle at the time of slaughter (3 d after completion of the Co-Synch + CIDR protocol). When total uterine histotroph AA was calculated (luteal + non-luteal horns) and analyzed by treatment with group in the model, the differences were: CON &amp;gt; NEG for 1) Trp as % of essential AA, and 2) Ser as % of total AA (P = 0.04 and 0.05, respectively). Tendencies for total tract histotroph were observed for Phe and Trp as a % of total AA (P = 0.07 and 0.06, respectively) for CON &amp;gt; NEG. Luteal histotroph Ser as a % of total AA was greater (P = 0.05) for CON vs. NEG. When evaluating non-luteal histotroph, CON had greater (P &amp;lt; 0.05) Cys as a % of total AA compared with NEG cows. Non-luteal histotroph Arg concentration tended (P = 0.10) to be greater for NEG vs. CON. These results demonstrate that feed intake affects cow AA supply in the uterine histotroph, and these AA (Trp, Ser, Phe, Cys and Arg) may function in critical nutrient pathways, reproductive tract vascularization, and antioxidant production, which are necessary for optimal fetal development.

Mechanism(s)-of-Action for Arginine Therapy in Children with Sickle Cell Disease and Vaso-Occlusive Pain: Results of a Pharmacokinetics/Pharmacodynamics Study

Introduction: Low L-Arginine (Arg) bioavailability is associated with sickle cell disease (SCD) mortality and morbidity, including acute pain severity. Multiple phase 2 trials support the safety and efficacy of Arg therapy in children with SCD experiencing vaso-occlusive pain. Nitric oxide (NO) is a potent vasodilator depleted in SCD due to hemolysis. As the obligate substrate for NO production, Arg's mechanism-of-action is unknown but thought to be related in part to NO production. Kyotorphin (KTP) is an endogenous opioid analgesic composed of the amino acids tyrosine and Arg. Its nociceptive effects are through induction of Met-enkephalins release in the brain. Oral administration of Arg in wild-type mice increases the levels of KTP centrally. We have previously shown that Arg supplementation increases NO metabolites (NOx), improves mitochondrial function, decreases oxidative stress, and has opioid sparing effects in children with SCD. The association between IV Arg supplementation as a precursor to KTP in SCD is unknown and may represent a novel mechanism by which Arg decreases pain in patients with SCD. Objective: To analyze the results of a pharmacokinetics/pharmacodynamics study, evaluating the association between Arg supplementation and plasma levels of KTP and other potential mechanisms-of-action related to Arg in children with SCD and vaso-occlusive pain episodes (VOE). Methods: We conducted a pharmacokinetics/pharmacodynamics study of children aged 7-21 years with SCD hospitalized for VOE and randomized to treatment utilizing one of 3 dosing arms of Arg: 1) 100mg/kg IV three times/day, standard dose (n=4); 2) loading dose (200mg/kg) followed by standard dose (n=5); or 3) loading dose (200mg/kg) followed by continuous infusion (300mg/kg/day) until discharge (n=4). Plasma amino acids (arginine, ornithine, citrulline), global arginine bioavailability ratio (GABR; Arginine/[Citrulline+Ornithine]), KTP, NOx, exhaled NO, plasma arginase activity, and arginase-1 and -2 were measured. Mean±SD, paired t-tests, and Pearson correlation analyses between groups were performed where appropriate. Results: A total of 13 patients (age 13±3 years, 56% male, 88% Hb-SS, 85% on hydroxyurea) were enrolled. Statistically significant increases in plasma arginine levels (Fig1A), plasma KTP levels (Fig1B), and GABR from pre-dose (0 hour) to 1, 1.5, and 2 hours after arginine infusion were observed, with a return to baseline 8 hours after Arg administration. Arg and KTP levels peaked between 60-90 minutes after arginine infusion in all study arms (p&amp;lt;0.001, p=0.004 respectively). There were no significant differences in peak concentration across all study arm doses. Rise in KTP levels strongly correlated with changes in plasma Arg concentration ( r=0.72, p&amp;lt;0.0001). Plasma NOx levels significantly increased from pre-dose to Tmax (Tmax= 1-2 hours; mean percent change 156±313%, p=0.02), as did exhaled NO (mean percent change 31±27%, p=0.02). Arginase activity also increased significantly after IV Arg infusion peaking at approximately 90 minutes (mean percent change 137±183%, p= 0.03) with return to baseline at 8 hours, while there was no significant change in arginase-1 or -2 concentrations over time. Conclusion: IV Arg therapy increased plasma arginine concentration 2-5 times above baseline at presentation for VOE, and GABR also increased as expected in this pharmacokinetics study with both reaching a maximum concentration within 1 hour of infusion initiation in all dosing schemes. IV Arg supplementation increases plasma NOx levels suggesting a role for vasodilation as a potential mechanism-of-action during SCD-VOE. Exhaled NO also increased significantly, consistent with previous reports. Interestingly, IV Arg supplementation acutely increased arginase activity without a significant change in arginase concentration. Most notably, we report for the first time the impact of IV Arg therapy on plasma levels of KTP in SCD. As KTP is an endogenous opioid analgesic, this may represent a novel mechanism-of-action of Arg therapy that warrants further investigation. This observation may also have implications for the potential use of arginine supplementation in pain syndromes beyond sickle cell disease.

Carbomer/arginine intelligent viscoelastic fluid with adjustable CO2-responsive viscosity

Environmentally responsive intelligent viscoelastic fluids have been used in many fields in recent years. The rheological behavior of different intelligent viscoelastic fluids can be changed by different stimulation methods. Among them, CO2, as a non-toxic green and abundant stimulus method, has attracted much attention. Therefore, CO2-responsive intelligent viscoelastic fluids have been continuously reported, in which viscoelastic fluids with CO2-responsive viscosity increase have been more reported, while those with CO2-responsive viscosity decrease have been less reported. Herein, carbomer (CBM), as a pH-responsive polymer with potential CO2-responsiveness, is applied to CO2-responsive viscosity decreasing viscoelastic fluids. CBM and arginine (Arg) formed a new CO2-responsive viscoelastic fluid, which achieved a significant decrease in viscosity after CO2-response. Firstly, by comparing the effects of NaOH and Arg on the rheological behavior of CBM solution, it is demonstrated that Arg can extend the viscosity variation range of CBM solution before and after CO2-response, and Arg can switch between “physical crosslinking agent” and “viscosity reducing agent”, and it is verified from the microscopic perspective. Then, the effects of Arg concentration and CBM concentration on the CO2-responsiveness and rheological behavior of CBM/Arg viscoelastic fluid were investigated. The multiple reversible CO2-responsive viscosity of CBM/Arg viscoelastic fluid was verified. Finally, the viscoelastic variations of CBM/Arg viscoelastic fluid before and after the response were investigated by dynamic rheology.

Thermal stability and interfacial rheology of whey protein-corn oil emulsions: The effect of l-arginine fortification.

The effect of l-arginine (Arg) on the thermal stability of whey protein-corn oil emulsions was investigated to determine its role in improving emulsion stability. The results indicated that with an increase in Arg concentration, the emulsion stability index, emulsification activity index, and absolute ζ-potential increased initially and decreased after high-temperature sterilization. However, the mean particle size, apparent viscosity, creaming indices, and dynamic interfacial pressure of the emulsions first decreased and then increased, and the performance of samples that only showed an increase in pH could also improve the emulsification stability. These results clarify the mechanism by which Arg increases the thermal stability of emulsions.

Effects of rumen-protected lysine and methionine supplementation in low-crude protein diets on lactation performance, nitrogen metabolism, rumen fermentation, and blood metabolites in Holstein cows

The objective of the study was to investigate the effects of supplementing a low-protein diet with rumen-protected lysine (RP-Lys) and RP-methionine (RP-Met) on milk production, nitrogen metabolism, and rumen fermentation in dairy cows. Forty-eight Holstein dairy cows were blocked by parity (2.1 ± 0.17), milk production (32.1 ± 3.41 kg/d), and days in milk (124 ± 28 d), and randomly assigned to 1 of 4 dietary treatments: control diet (CON, 16 % CP), low-protein diet (LP, 14 % CP, negative control), a moderate diet supplemented with RP-Met (31 g/d) and RP-Lys (MPML, 15 % CP, 110 g/d), and LP diet with RP-Met (50 g/d) and RP-Lys (LPML, 14 % CP, 150 g/d). Dry matter intake (DMI), feed efficiency, and the apparent total tract digestibility of nutrients was not affected by treatments. Compared with the CON, the milk yield was increased in the MPML treatment (P = 0.03) while decreased in the LP treatment (P = 0.02). Milk protein yield in the MPML treatment was higher than that in the other treatments (P < 0.05). The LP, LPML, and MPML treatments had lower concentrations of milk urea-N and plasma urea-N than CON treatments (P < 0.01). The LP, LPML, and MPML treatments decreased the plasma histidine (His) concentration (P < 0.01), while the LP and LPML treatments decreased plasma arginine (Arg) concentration (P < 0.05) compared to the CON treatment. Plasma Met concentration in the MPML treatment was increased (P < 0.01), whereas was decreased in the LP treatment, compared with the CON (P < 0.05). The N intake (g/d) in the LP, LPML, and MPML treatments was lower than that in the CON treatment (P < 0.01), while fecal N (g/d) was not affected by treatments. However, CON treatment increased the urine N (g/d), total excreta N (g/d), N secretion and excretion (g/d), and the proportions of urine N to N intake, whereas decreased the proportion of milk N to N intake and milk N efficiency, compared to the other three treatments (P < 0.01). The rumen concentration of ammonia nitrogen in the LP, LPML, and MPML treatments was lower than that in the CON treatment (P < 0.05). Collectively, the low-protein diets supplemented with RP-Met and RP-Lys could increase milk N efficiency and dramatically decrease urinary N losses. From the perspective of N emission reduction, a 2% reduction in dietary CP was rational.

PMMA/paper hybrid microfluidic chip for simultaneous determination of arginine and valine in human plasma.

Thesimultaneous determination is reported of arginine (Arg) and valine (Val) amino acids in plasma using flower-shaped μPADs and PMMA/paper hybrid microfluidic chip based on AuNPs capped with R-thiazolidine-4-carboxylic acid (THP). In this article, the evaluation procedure is based on the smartphone colorimetric detection mechanism that results from the aggregation of the THP-AuNPs with the addition of amino acids and visual color change from red to blue. Arg and Val were selectively determined with good reproducibility and an acceptable linearity range. The flower-shaped (μPADs) provides many advantages, including low cost, reasonable sensitivity, simple and fast performance, simultaneous detection, disposable use, and high sample throughput compared with conventional colorimetric method using cuvette cells. The ratios between the absorbance wavelength at (A650/A525) and (A685/A525) are linearly proportional to the concentration of Arg and Val. Under the optimum conditions, the calibration range in aqueous solutions is 0.0068-100.0 and 0.0056-75.0µM with a limit of detection of 2.25 and 1.86nM for Arg and Val at pH 7.0, respectively. In the case of μPADs, the calibration curves for Arg and Val showed good linearity in the concentration range 0.01-75.0µM. The detection limits for the analytes were 3.51nM and 3.44nM for Arg and Val, respectively. In addition, a PMMA/paper hybrid microfluidic chip was successfully employed to determine Arg and Val in plasma samples with a relative error below 5%.

Preparation of electrochemical sensor based on glassy carbon electrode and its specificity and sensitivity for directional detection of antibiotic resistance genes spreading in the water environment.

Antibiotic-resistant bacteria/resistance genes (ARB/ARGs) have been paid much attention due to the environmental risks they might bring. They were demonstrated to be widespread in surface water and wastewater. Determining the concentrations of ARGs is the first step to evaluate the degree of pollution. In this study, electrochemical detection technology was studied due to its advantages of low cost, fast response, and satisfactory selectivity. Additionally, the electrochemical sensor technology was used to determine the concentration of a ubiquitous ARG (ampicillin gene blaTEM) in the water environment. A kind of electrochemical sensor was prepared on a glassy carbon electrode (GCE). The results of X-ray photoelectron spectroscopy (XPS) and cyclic voltammetry (CV) curves indicated that the single-stranded DNA (ssDNA) probe can be successfully immobilized on the surface of the GCE. In addition, the performance of hybridization between the ssDNA probe and the target DNA at diverse temperatures was compared, of which 35°C was the optimum. Moreover, the change of charge transfer resistance (ΔRct) for the GCE sensor hybridizing with complementary DNA was much higher than that of DNA with the mismatched base, which indicated that the electrochemical sensor prepared in this study was specific. The sensitivity of the sensor was also proved by the strong correlation between the concentrations of ARGs and ΔRct (with the correlation coefficient (R2) of 0.9905). All in all, this study is meaningful for the comprehend on the detection of ARGs through the electrochemical method.

L-Arginine increases AMPK phosphorylation and the oxidation of energy substrates in hepatocytes, skeletal muscle cells, and adipocytes.

Previous work has shown that dietary L-arginine (Arg) supplementation reduced white fat mass in obese rats. The present study was conducted with cell models to define direct effects of Arg on energy-substrate oxidation in hepatocytes, skeletal muscle cells, and adipocytes. BNL CL.2 mouse hepatocytes, C2C12 mouse myotubes, and 3T3-L1 mouse adipocytes were treated with different extracellular concentrations of Arg (0, 15, 50, 100 and 400µM) or 400µM Arg + 0.5mM NG-nitro-L-arginine methyl ester (L-NAME; an NOS inhibitor) for 48h. Increasing Arg concentrations in culture medium dose-dependently enhanced (P < 0.05) the oxidation of glucose and oleic acid to CO2 in all three cell types, lactate release from C2C12 cells, and the incorporation of oleic acid into esterified lipids in BNL CL.2 and 3T3-L1 cells. Arg at 400µM also stimulated (P < 0.05) the phosphorylation of AMP-activated protein kinase (AMPK) in all three cell types and increased (P < 0.05) NO production in C2C12 and BNL CL.2 cells. The inhibition of NOS by L-NAME moderately reduced (P < 0.05) glucose and oleic acid oxidation, lactate release, and the phosphorylation of AMPK and acetyl-CoA carboxylase (ACC) in BNL CL.2 cells, but had no effect (P > 0.05) on these variables inC2C12 or 3T3-L1 cells. Collectively, these results indicate that Arg increased AMPK activity and energy-substrate oxidation in BNL CL.2, C2C12, and 3T3-L1 cells through both NO-dependent and NO-independent mechanisms.

Removal of Diverse and Abundant ARGs by MF-NF Process from Pig Manure and Digestate.

Antimicrobial resistances are emerging as one main threat to worldwide human health and are expected to kill 10 million people by 2050. Intensive livestock husbandry, along with biogas digestate, are considered as one of the biggest ARG reservoirs. Despite major concerns, little information is available on the diversity and abundance of various ARGs in small to large scale pig farms and biogas digestate slurry in Germany, followed by their consequent removal using microfiltration (MF)–nanofiltration (NF) process. Here, we report the identification and quantification of 189 ARGs in raw manure and digestate samples, out of which 66 ARGs were shared among manures and 53 ARGs were shared among both manure and digestate samples. The highest reported total ARG copy numbers in a single manure sampling site was 1.15 × 108 copies/100 µL. In addition, we found the absolute concentrations of 37 ARGs were above 105 copies/100 μL. Filtration results showed that the highly concentrated ARGs (except aminoglycoside resistance ARGs) in feed presented high log retention value (LRV) from 3 to as high as 5 after the MF-NF process. Additionally, LRV below 2 was noticed where the initial absolute ARG concentrations were ≤103 copies/100 μL. Therefore, ARG removal was found to be directly proportional to its initial concentration in the raw manure and in digestate samples. Consequently, some ARGs (tetH, strB) can still be found within the permeate of NF with up to 104 copies/100 μL.

P870: DEFINING A NOVEL FUNCTION FOR THE POST-TRANSLATIONAL MODIFICATION UFMYLATION IN THE ADAPTIVE RESPONSE TO ARGININE DEPRIVATION IN MULTIPLE MYELOMA

Background: Our previous work showed that arginine deprivation is associated to multiple myeloma (MM) bortezomib refractoriness, but the molecular basis of this adaptive response is still largely unknown. Aims: We designed an integrative transcriptional and metabolic study to explore the contemporary transcriptional and metabolic changes occurring upon arginine deprivation in four human myeloma cell lines (HMCLs, U266, NCI-H929, OPM2 and MM1.s). Methods: HMCLs were individually cultured with customized complete with different Arg concentrations, correspondent respectively to 100%, 25% and 10% of the arginine concentration in MM bone marrow. After 24-48 hours of culture, the cells were collected for global metabolomic analysis (Metabolon Inc) and transcriptome profiling by Illumina platform. Apoptosis and mitochondrial depolarization were measured by FACS. Protein expression was evaluated by western blot analysis. Results: In all tested HMCLs the progressive arginine deprivation (range 1124-0 µM) induced delay in cell cycle until proliferation arrest (in total lack of arginine in culture media), with increase of G0-G1 length, at specific timepoints for each cell line tested. However global protein synthesis was not affected and surprisingly, in all tested cell lines, the monoclonal component secretion in extracellular medium was preserved after 96 hours of arginine starvation. At 48 hours of arginine deprivation (range 1124-100 µM) GCN2 pathway was induced in HMCLs with consequent increase of basal levels of ATF4, p62, GABARAP and autophagy flux. After 48 hours of arginine starvation, coupled metabolomics and RNA-seq, disclosed an impairment in the pool of nucleotides and activation of salvage purine pathway, that could explain changes in cell cycle and proliferation. Arginine-deprived MM cells had higher levels of choline and phospho-ethanolamine with lower levels of glycerophosphorylcholine (GPC) compared to controls suggesting an effect of arginine-deprivation on membrane dynamics, associated to increased production of fatty acids, palmitate (16:0) and stearate (18:0), required for the generation of new membranes. Culture in arginine deficient media resulted in complete depletion of reduced glutathione (GSH) and oxidized glutathione (GSSG), with depletion of gamma-glutamylcysteine, indicating increased levels of oxidative stress. Gene set enrichment analysis (GSEA) showed deep transcriptome rearrangements, involving upregulation of genes required for the unfolded protein response, NF-kB response to TNF, p53 pathway and networks and proteosome degradation, with a minimal effect on metabolism features, except the upregulation of genes involved in lactate generation and degradation. In all cell lines, transcripts involved in the UFMylation pathway were affected, with reduction of UFSP2 and increase of UFMYlation targets RPL26, PKM2, ENO-1, PGK-1 and SQSTM1/p62. In a large series of primary samples (9N - 20MGUS - 33SMM - 170MM - 24PPCL - 12SPCL) and 18 MM cell lines, through bioinformatic analysis of previously published datasets (GENE1.0_BAv20_Neri-Gutierrez), we found that myeloma progression was associated to increased expression of UFMYlation targets ENO-1, PGK1 and DLD. Summary/Conclusion: Taken together, our data clearly indicate how arginine starvation can induce an heterogeneous adaptation processes occur in individual tumour clones. The ER stress adaptive response triggered by arginine deprivation promotes UFMylation activation, due to downregulation of UFSP2 and accumulation of RPN1/RPL26 targets.