Borate and phosphite treatments of potato plants (Solanum tuberosum L.) as a proof of concept to reinforce the cell wall structure and reduce starch digestibility.

Potatoes are one of the main sources of carbohydrates in human diet, however they have a high glycaemic index (GI). Hence, developing new agricultural and industrial strategies to produce low GI potatoes represents a health priority to prevent obesity and related diseases. In this work, we investigated whether treatments of potato plants with elicitors of plant defence responses can lead to a reduction of tuber starch availability and digestibility, through the induction of cell wall remodelling and stiffening. Treatments with phosphites (KPhi) and borate were performed, as they are known to activate plant defence responses that cause modifications in the architecture and composition of the plant cell wall. Data of suberin autofluorescence demonstrated that potato plants grown in a nutrition medium supplemented with KPhi and borate produced tubers with a thicker periderm, while pectin staining demonstrated that KPhi treatment induced a reinforcement of the wall of storage parenchyma cells. Both compounds elicited the production of H2O2, which is usually involved in cell-wall remodelling and stiffening reactions while only KPhi caused an increase of the total content of phenolic compounds. A two-phase digestion in vitro assay showed that treatment with KPhi determined a significant decrease of the starch hydrolysis rate in potato tubers. This work highlights the ability of cell wall architecture in modulating starch accessibility to digestive enzymes, paving the way for new agronomic practices to produce low GI index potatoes.

Effects of high potassium iodate intake on iodine metabolism and antioxidant capacity in rats.

BACKGROUND: KIO3 and KI are the most common salt iodization agents. Coincidentally, iodine exists naturally in high-iodine drinking water in the form of iodide (I-) or iodate (IO3-). As an oxidizing substance, IO3- should be reduced to I- before it can be effectively used by the thyroid. However, there is a lack of systematic studies on the metabolic process of high dose KIO3in vivo. METHODS: The iodine metabolism processes in the thyroid and serum of rats after high KIO3 intake were determined using high-performance liquid chromatography-inductively coupled plasma-mass spectrometry (HPLC/ICP-MS) and arsenic cerium catalytic spectrophotometry. The changes of redox activity in the serum, thyroid, liver, and kidneys were observed by detecting total antioxidative activity (TAA). RESULTS: High doses of IO3- were completely reduced to I-in vivo within 0.5 h. The level of organic bound iodine in the serum was stable, while the organic bound iodine in the thyroid increased to a plateau after intake of high-dose KIO3. The levels of total iodine and I- in serum and thyroid increased quickly, then all decreased after reaching the maximum absorption peak, and I- had two absorption peaks in serum. The thyroid blocking dose of I- was 0.5 mg/kg in rat. Additionally, high KIO3 intake did not influence the TAA in serum and other tissues. CONCLUSION: The body is able to reduce and utilize high doses of KIO3 ingested through the digestive tract. The metabolism of high KIO3in vivo is characterized by two absorption process of I- in serum and the thyroid blocking effect. Moreover, a single intake of high-dose KIO3 does not affect TAA in vivo. The results suggest that such excess IO3- may have be reduced in the digestive tract before I- enters the blood.

Optimization of heterotrophic cultivation of Chlorella sp. HS2 using screening, statistical assessment, and validation.

The heterotrophic cultivation of microalgae has a number of notable advantages, which include allowing high culture density levels as well as enabling the production of biomass in consistent and predictable quantities. In this study, the full potential of Chlorella sp. HS2 is explored through optimization of the parameters for its heterotrophic cultivation. First, carbon and nitrogen sources were screened in PhotobioBox. Initial screening using the Plackett-Burman design (PBD) was then adopted and the concentrations of the major nutrients (glucose, sodium nitrate, and dipotassium phosphate) were optimized via response surface methodology (RSM) with a central composite design (CCD). Upon validation of the model via flask-scale cultivation, the optimized BG11 medium was found to result in a three-fold improvement in biomass amounts, from 5.85 to 18.13 g/L, in comparison to a non-optimized BG11 medium containing 72 g/L glucose. Scaling up the cultivation to a 5-L fermenter resulted in a greatly improved biomass concentration of 35.3 g/L owing to more efficient oxygenation of the culture. In addition, phosphorus feeding fermentation was employed in an effort to address early depletion of phosphate, and a maximum biomass concentration of 42.95 g/L was achieved, with biomass productivity of 5.37 g/L/D.

Acute interaction between oral glucose (75 g as Lucozade) and inorganic nitrate: Decreased insulin clearance, but lack of blood pressure-lowering.

AIMS: Dietary inorganic nitrate (NO3- ) lowers peripheral blood pressure (BP) in healthy volunteers, but lacks such effect in individuals with, or at risk of, type 2 diabetes mellitus (T2DM). Whilst this is commonly assumed to be a consequence of chronic hyperglycaemia/hyperinsulinaemia, we hypothesized that acute physiological elevations in plasma [glucose]/[insulin] blunt the haemodynamic responses to NO3- , a pertinent question for carbohydrate-rich Western diets. METHODS: We conducted an acute, randomized, placebo-controlled, double-blind, crossover study on the haemodynamic and metabolic effects of potassium nitrate (8 or 24 mmol KNO3 ) vs. potassium chloride (KCl; placebo) administered 1 hour prior to an oral glucose tolerance test in 33 healthy volunteers. RESULTS: Compared to placebo, there were no significant differences in systolic or diastolic BP (P = 0.27 and P = 0.30 on ANOVA, respectively) with KNO3 , nor in pulse wave velocity or central systolic BP (P = 0.99 and P = 0.54 on ANOVA, respectively). Whilst there were significant elevations from baseline for plasma [glucose] and [C-peptide], no differences between interventions were observed. A significant increase in plasma [insulin] was observed with KNO3 vs. KCl (n = 33; P = 0.014 on ANOVA) with the effect driven by the high-dose cohort (24 mmol, n = 13; P < 0.001 on ANOVA; at T = 0.75 h mean difference 210.4 pmol/L (95% CI 28.5 to 392.3), P = 0.012). CONCLUSIONS: In healthy adults, acute physiological elevations of plasma [glucose] and [insulin] result in a lack of BP-lowering with dietary nitrate. The increase in plasma [insulin] without a corresponding change in [C-peptide] or [glucose] suggests that high-dose NO3- decreases insulin clearance. A likely mechanism is via NO-dependent inhibition of insulin-degrading enzyme.

The negative effect of unloading exceeds the bone-sparing effect of alkaline supplementation: a bed rest study.

Potassium bicarbonate was administrated to an already alkaline diet in seven male subjects during a 21-day bed rest study and was able to decrease bed rest induced increased calcium excretion but failed to prevent bed rest-induced bone resorption. INTRODUCTION: Supplementation with alkali salts appears to positively influence calcium and bone metabolism and, thus, could be a countermeasure for population groups with an increased risk for bone loss. However, the extent to which alkalization counteracts acid-induced bone resorption or whether it merely has a calcium and bone maintenance effect is still not completely understood. In the present study, we hypothesized that additional alkalization to an already alkaline diet can further counteract bed rest-induced bone loss. METHODS: Seven healthy male subjects completed two parts of a crossover designed 21-day bed rest study: bed rest only (control) and bed rest supplemented with 90 mmol potassium bicarbonate (KHCO3) daily. RESULTS: KHCO3supplementation during bed rest resulted in a more alkaline status compared to the control intervention, demonstrated by the increase in pH and buffer capacity level (pH p = 0.023, HCO3p = 0.02, ABE p = 0.03). Urinary calcium excretion was decreased during KHCO3 supplementation (control 6.05 ± 2.74 mmol/24 h; KHCO3 4.87 ± 2.21 mmol/24 h, p = 0.03); whereas, bone formation was not affected by additional alkalization (bAP p = 0.58; PINP p = 0.60). Bone resorption marker UCTX tended to be lower during alkaline supplementation (UCTX p = 0.16). CONCLUSIONS: The more alkaline acid-base status, achieved by KHCO3 supplementation, reduced renal calcium excretion during bed rest, but was not able to prevent immobilization-induced bone resorption. However, advantages of alkaline salts on bone metabolism may occur under acidic metabolic conditions or with respect to the positive effect of reduced calcium excretion within a longer time frame. TRIAL REGISTRATION: Trial number: NCT01509456.

Alkalinization with potassium bicarbonate improves glutathione status and protein kinetics in young volunteers during 21-day bed rest.

BACKGROUND & AIMS: Physical inactivity is associated with lean body mass wasting, oxidative stress and pro-inflammatory changes of cell membrane lipids. Alkalinization may potentially counteract these alterations. We evaluated the effects of potassium bicarbonate supplementation on protein kinetics, glutathione status and pro- and anti-inflammatory polyunsaturated fatty acids (PUFA) in erythrocyte membranes in humans, during experimental bed rest. METHODS: Healthy, young, male volunteers were investigated at the end of two 21-day bed rest periods, one with, and the other without, daily potassium bicarbonate supplementation (90 mmol × d-1), according to a cross-over design. Oxidative stress in erythrocytes was evaluated by determining the ratio between reduced (GSH) and oxidized glutathione (GSSG). Glutathione turnover and phenylalanine kinetics, a marker of whole body protein metabolism, were determined by stable isotope infusions. Erythrocyte membranes PUFA composition was analyzed by gas-chromatography. RESULTS: At the end of the two study periods, urinary pH was 10 ± 3% greater in subjects receiving potassium bicarbonate supplementation (7.23 ± 0.15 vs. 6.68 ± 0.11, p < 0.001). Alkalinization increased total glutathione concentrations by 5 ± 2% (p < 0.05) and decreased its rate of clearance by 38 ± 13% (p < 0.05), without significantly changing GSH-to-GSSG ratio. After alkalinization, net protein balance in the postabsorptive state improved significantly by 17 ± 5% (p < 0.05) as well as the sum of n-3 PUFA and the n-3-to-n-6 PUFA ratio in erythrocyte membranes (p < 0.05). CONCLUSIONS: Alkalinization during long-term inactivity is associated with improved glutathione status, anti-inflammatory lipid pattern in cell membranes and reduction in protein catabolism at whole body level. This study suggests that, in clinical conditions characterized by inactivity, oxidative stress and inflammation, alkalinization could be a useful adjuvant therapeutic strategy.

Phosphite alters the behavioral response of potato tuber moth (Phthorimaea operculella) to field-grown potato.

BACKGROUND: The potato tuber moth (PTM) (Phthorimaea operculella) is a pest of solanaceous species that causes serious damage to potato tubers and tomato fruits. Control is mainly dependent on the use of synthetic chemicals, which pose a risk to the environment and health of farmers, especially in developing countries where application safety rules are often neglected. In this study we aimed at investigating the effects of a plant resistance inducer (PRI) potassium phosphite on PTM larval population density and PTM parasitoid levels, which can be used as biocontrol agents. We also tested whether intercropping with tomato, which is less attractive to PTM, provided a spatial border to further reduce PTM numbers. RESULTS: In two different locations over two seasons, we showed that foliar application of phosphite more than halved the PTM larval populations on potato, and that PTM parasitoid numbers were unaffected. No consistent reduction in PTM was achieved by intercropping potato with tomato. CONCLUSIONS: Phosphite reduced PTM numbers in the field without interfering with autochthonous parasitoids, indicating its suitability as part of an Integrated Pest Management strategy. Ex situ choice tests showed that phosphite-treated potato deterred PTM, which could be a reason for the control of PTM in the field. © 2018 Society of Chemical Industry.

Phosphorus application reduces aluminum toxicity in two Eucalyptus clones by increasing its accumulation in roots and decreasing its content in leaves.

Under acidic conditions, aluminum (Al) toxicity is an important factor limiting plant productivity; however, the application of phosphorus (P) might alleviate the toxic effects of Al. In this study, seedlings of two vegetatively propagated Eucalyptus clones, E. grandis × E. urophylla 'G9' and E. grandis × E. urophylla 'DH32-29'were subjected to six treatments (two levels of Al stress and three levels of P). Under excessive Al stress, root Al content was higher, whereas shoot and leaf Al contents were lower with P application than those without P application. Further, Al accumulation was higher in the roots, but lower in the shoots and leaves of G9 than in those of DH32-29. The secretion of organic acids was higher under Al stress than under no Al stress. Further, under Al stress, the roots of G9 secreted more organic acids than those of DH32-29. With an increase in P supply, Al-induced secretion of organic acids from roots decreased. Under Al stress, some enzymes, including PEPC, CS, and IDH, played important roles in organic acid biosynthesis and degradation. Thus, our results indicate that P can reduce Al toxicity via the fixation of elemental Al in roots and restriction of its transport to stems and leaves, although P application cannot promote the secretion of organic acid anions. Further, the higher Al-resistance of G9 might be attributed to the higher Al accumulation in and organic acid anion secretion from roots and the lower levels of Al in leaves.

Association of Urinary Citrate With Acid-Base Status, Bone Resorption, and Calcium Excretion in Older Men and Women.

Context: Elevated urine net acid excretion (NAE), indicative of subclinical metabolic acidosis, has been associated with higher bone turnover. Urine citrate, which is a common clinical measure, changes in response to acid-base status but its association with bone turnover is uncertain. Objective: We evaluated the association between change in urine citrate and change in bone turnover and calcium excretion. Design, Intervention, and Participants: A total of 233 healthy men and women ≥60 years old were randomly assigned to 1.0 mmol/kg/d potassium bicarbonate (KHCO3), 1.5 mmol/kg/d KHCO3, or placebo for 84 days. Outcome Measures: Urine citrate, NAE, N-telopeptide of collagen type-I (NTX), calcium excretion, and serum amino-terminal propeptide of type 1 procollagen (P1NP) were measured before and after intervention. Results: Urine citrate increased dose dependently after KHCO3 supplementation (P trend < 0.001). The urine citrate change was significantly inversely associated with P1NP change (P = 0.021) but not with change in NTX (P = 0.051) or calcium excretion (P = 0.652). The NAE change was positively associated with change in NTX and calcium excretion (P ≤ 0.003) but not with change in P1NP (P = 0.051). When the urine citrate change and NAE change were included in the same model, the urine citrate change was not associated with change in NTX, calcium excretion, or serum P1NP (P ≥ 0.086), whereas change in NAE remained associated with change in NTX and calcium excretion (P ≤ 0.003). Conclusion: Urine citrate may not be a suitable alternative to NAE when assessing acid-base status in relation to bone turnover in older adults.

NaK alloy-induced in vivo tumor ablation therapy.

PURPOSE: Alkali metal ablation is newly emerging as an effective, economic and minimally invasive ablation therapy. This study is dedicated to demonstrate the high efficiency of NaK alloy ablation on in vivo tumors with different stages in mice. MATERIAL AND METHODS: Panc02 tumor cells were injected into 21 female C57B/L mice, which were divided into three groups. Two experimental groups of mice received the same percutaneous NaK alloy injection for a week apart. The inner temperature response and surface temperature distribution were measured using a thermal couple and an infrared camera. After each ablation experiment, two mice in each group were chosen randomly to make pathological sections. The tumor volumes were measured once every two days. At the end, all tumors were cut off to calculate the tumor inhibition rates. RESULTS: The NaK alloy-induced ablation therapy produced an obvious temperature increase (85 °C) in the ablation region and the high temperature distribution was relatively concentrated. The histopathology sections showed that developing stage tumors received incomplete destruction of the malignant cells compared with early stage tumors. The tumor inhibition rate in the early and developing tumor treatment groups were 88.5% and 67.6%, respectively. CONCLUSIONS: This technology provides a nearly thorough ablation treatment for early stage tumors and also a palliative treatment for developing tumors.

Iodine-Rich Herbs and Potassium Iodate Have Different Effects on the Oxidative Stress and Differentiation of TH17 Cells in Iodine-Deficient NOD.H-2h4 Mice.

Iodine-rich herbs such as seaweed, kelp, and sea tangle were widely used to treat various types of goiter with good effect and without any adverse side effects in China. When compared with potassium iodate (PI), iodine-rich herbs had a positive effect on the recovery of goiter resulting from iodine deficiency without any obvious harmful effects. In NOD.H-2h4 mice, an autoimmune thyroiditis-prone model, iodine excess can increase infiltration of lymphocytes and structural damage of the thyroid follicles, hence resulting in thyroiditis. Until now, there has been little research on the comparative effects of PI and iodine-rich herbs on thyroid in an autoimmune thyroiditis-prone model. This study was designed to compare the different effects of iodine-rich herbs and PI on the thyroid gland in iodine-deficient NOD.H-2h4 mice. Excessive intake of PI cause oxidative injury in the thyroid gland and increase the risk of autoimmune thyroiditis, while iodine-rich herbs cause less oxidative injury, significantly enhancing antioxidant capacity, and inhibit the high differentiation of Th17 cells in the thyroid glands of NOD.H-2h4 mice.

T2-relaxation time increases in lumbar intervertebral discs after 21d head-down tilt bed-rest.

OBJECTIVES: Spaceflight back pain and intervertebral disc (IVD) herniations cause problems in astronauts. Purpose of this study was to assess changes in T2-relaxation-time through MRI measurements before and after head-down tilt bed-rest, a spaceflight analog. METHODS: 8 men participated in the bed-rest study. Subjects remained in 6° head down tilt bed-rest in two campaigns of 21 days, and received a nutritional intervention (potassium bicarbonate 90 mmol/d) in a cross-over design. MRI measurements were performed 2 days before bed-rest, as well as one and five days after getting up. Image segmentation and data analysis were conducted for the IVDs Th12/L1 to L5/S1. RESULTS: 7 subjects, average age of 27.6 (SD 3.3) years, completed the study. Results showed a significant increase in T2-time in all IVDs (p⟨0.001), more pronounced in the nucleus pulposus than in the annulus fibrosus (p⟨0.001). Oral potassium bicarbonate did not show an effect (p=0.443). Pfirrmann-grade correlated with the T2-time (p⟨0.001). CONCLUSIONS: 6° head-down tilt bed-rest leads to a T2-time increase in lumbar IVDs. Oral potassium bicarbonate supplementation does not have an effect on IVD T2-time.

Bromide supplementation exacerbated the renal dysfunction, injury and fibrosis in a mouse model of Alport syndrome.

A seminal study recently demonstrated that bromide (Br-) has a critical function in the assembly of type IV collagen in basement membrane (BM), and suggested that Br- supplementation has therapeutic potential for BM diseases. Because salts of bromide (KBr and NaBr) have been used as antiepileptic drugs for several decades, repositioning of Br- for BM diseases is probable. However, the effects of Br- on glomerular basement membrane (GBM) disease such as Alport syndrome (AS) and its impact on the kidney are still unknown. In this study, we administered daily for 16 weeks 75 mg/kg or 250 mg/kg (within clinical dosage) NaBr or NaCl (control) via drinking water to 6-week-old AS mice (mouse model of X-linked AS). Treatment with 75 mg/kg NaBr had no effect on AS progression. Surprisingly, compared with 250 mg/kg NaCl, 250 mg/kg NaBr exacerbated the progressive proteinuria and increased the serum creatinine and blood urea nitrogen in AS mice. Histological analysis revealed that glomerular injury, renal inflammation and fibrosis were exacerbated in mice treated with 250 mg/kg NaBr compared with NaCl. The expressions of renal injury markers (Lcn2, Lysozyme), matrix metalloproteinase (Mmp-12), pro-inflammatory cytokines (Il-6, Il-8, Tnf-α, Il-1ß) and pro-fibrotic genes (Tgf-ß, Col1a1, α-Sma) were also exacerbated by 250 mg/kg NaBr treatment. Notably, the exacerbating effects of Br- were not observed in wild-type mice. These findings suggest that Br- supplementation needs to be carefully evaluated for real positive health benefits and for the absence of adverse side effects especially in GBM diseases such as AS.

Comparison between the effects of potassium phosphite and chitosan on changes in the concentration of Cucurbitacin E and on antibacterial property of Cucumis sativus.

BACKGROUND: Cucurbitacins are mostly found in the members of the family Cucurbitaceae and are responsible for the bitter taste of cucumber. Pharmacological activities such as anti-bacterial and anti-tumor effects have been attributed to these structurally divers triterpens. The aim of this study was to investigate the effect of potassium phosphite (KPhi) and chitosan on Cucurbitacin E (CuE) concentration in different tissues of Cucumis sativus. The antibacterial effect of plant ethanolic extracts was also examined against E.coli PTCC 1399 and Pseudomonas aeruginosa PTCC 1430 bacterial strains. METHODS: After emergence of secondary leaves, cucumber plants were divided into 4 groups (each group consisted of 6 pots and each pot contained one plant) and different treatments performed as follows: group1. Leaves were sprayed with distilled water (Control), group 2. The leaves were solely treated with potassium phosphite (KPhi), group 3. Leaves were solely sprayed with chitosan (Chitosan), group 4. Leaves were treated with KPhi and chitosan (KPhi + chitosan). The KPhi (2 g L-1) and chitosan (0.2 g L-1) were applied twice every 12 h for one day. Fruits, roots and leaves were harvested 24 h later. The ethanolic extract of plant organs was used for determination of CuE concentration using HPLC approach. The antimicrobial activity was evaluated by the agar well diffusion method. The experiments were arranged in a completely randomized design (CRD) and performed in six biological replications for each treatment. Analysis of variance was performed by one-way ANOVA and Dunnette multiple comparison using SPSS. RESULTS: The highest level of CuE was recorded in fruit (2.2 g L-1) of plants under concomitant applications of KPhi and chitosan. Result of antibacterial activity evaluation showed that under concomitant treatments of KPhi and chitosan, fruit extract exhibited the highest potential for activity against E. coli PTCC 1399 (with mean zone of inhibition equal to 36 mm) and Pseudomonas aeruginosa PTCC 1430 (with mean zone of inhibition equal to 33 mm). CONCLUSIONS: KPhi and chitosan can induce production of CuE compound and increase antibacterial potential of cucumber plant extract. The application of KPhi and chitosan may be considered as promising prospect in the biotechnological production of CuE.

The response of growth and patulin production of postharvest pathogen Penicillium expansum to exogenous potassium phosphite treatment.

In this study, the effects of exogenous potassium phosphite (Phi) on growth and patulin production of postharvest pathogen Penicillium expansum were assessed. The results indicated that P. expansum under 5mmol/L Phi stress presented obvious development retardation, yield reduction of patulin and lower infectivity to apple fruit. Meanwhile, expression analysis of 15 genes related to patulin biosynthesis suggested that Phi mainly affected the early steps of patulin synthetic route at transcriptional level. Furthermore, a global view of proteome and transcriptome alteration of P. expansum spores during 6h of Phi stress was evaluated by iTRAQ (isobaric tags for relative and absolute quantitation) and RNA-seq (RNA sequencing) approaches. A total of 582 differentially expressed proteins (DEPs) and 177 differentially expressed genes (DEGs) were acquired, most of which participated in carbohydrate metabolism, amino acid metabolism, lipid metabolism, genetic information processing and biosynthesis of secondary metabolites. Finally, 39 overlapped candidates were screened out through correlational analysis between iTRAQ and RNA-seq datasets. These findings will afford more precise and directional clues to explore the inhibitory mechanism of Phi on growth and patulin biosynthesis of P. expansum, and be beneficial to develop effective controlling approaches based on Phi.

The effect of six days of dietary nitrate supplementation on performance in trained CrossFit athletes.

BACKGROUND: While it is well established that dietary nitrate reduces the metabolic cost of exercise, recent evidence suggests this effect is maintained 24 h following the final nitrate dose when plasma nitrite levels have returned to baseline. In addition, acute dietary nitrate was recently reported to enhance peak power production. Our purpose was to examine whether chronic dietary nitrate supplementation enhanced peak power 24 h following the final dose and if this impacted performance in a heavily power-dependent sport. METHODS: In a double-blind, randomized, crossover design, maximal aerobic capacity, body composition, strength, maximal power (30 s Wingate), endurance (2 km rowing time trial), and CrossFit performance (Grace protocol) were assessed before and after six days of supplementation with nitrate (NO) (8 mmol·potassium nitrate·d-1) or a non-caloric placebo (PL). A 10-day washout period divided treatment conditions. Paired t-tests were utilized to assess changes over time and to compare changes between treatments. RESULTS: Peak Wingate power increased significantly over time with NO (889.17 ± 179.69 W to 948.08 ± 186.80 W; p = 0.01) but not PL (898.08 ± 183.24 W to 905.00 ± 157.23 W; p = 0.75). However, CrossFit performance was unchanged, and there were no changes in any other performance parameters. CONCLUSION: Consuming dietary nitrate in the potassium nitrate salt form improved peak power during a Wingate test, but did not improve elements of strength or endurance in male CrossFit athletes.

Inorganic Nitrate Supplementation in Young and Old Obese Adults Does Not Affect Acute Glucose and Insulin Responses but Lowers Oxidative Stress.

BACKGROUND: Aging and obesity are associated with raised oxidative stress and a reduction of nitric oxide (NO) bioavailability, with subsequent decline in insulin sensitivity and endothelial function. Inorganic nitrate is converted into NO via a 2-step reduction process and may be an effective nutritional intervention to modify vascular and metabolic functions. OBJECTIVES: This study tested whether inorganic nitrate supplementation improved glucose disposal and attenuated the acute effects of hyperglycemia on oxidative stress, inflammation, and vascular function in young and old obese participants. METHODS: Ten young (aged 18-44 y) and 10 old (aged 55-70 y) obese participants consumed 75 g glucose followed by either potassium nitrate (7 mg/kg body weight) or potassium chloride (placebo) in a randomized, double-blind crossover design. Resting blood pressure (BP), endothelial function, and blood biomarkers were measured for 3 h postintervention. Biomarkers included plasma nitrate/nitrite (NOx), glucose, insulin, cyclic GMP, interleukin 6, 3-nitrotyrosine, E- and P-selectins, intercellular adhesion molecule 3 (ICAM-3), and thrombomodulin, as well as superoxide in freshly isolated peripheral blood mononuclear cells (PBMCs). RESULTS: Inorganic nitrate supplementation did not affect plasma glucose (P = 0.18) or insulin (P = 0.26) responses. The increase in plasma NOx concentrations 3 h after the administration of inorganic nitrate was significantly higher in young than in old participants (234% increase compared with 149% increase, respectively, P < 0.001). Plasma 3-nitrotyrosine concentrations declined significantly after inorganic nitrate supplementation compared with placebo (3 h postdose, 46% decrease compared with 27% increase, respectively, P = 0.04), and a similar nonsignificant trend was observed for superoxide concentrations (3 h postdose, 16% decrease compared with 23% increase, respectively, P = 0.06). Plasma cyclic GMP, ICAM-3, and thrombomodulin concentrations differed between young and old participants (P < 0.01). Inorganic nitrate supplementation did not improve BP or endothelial function. CONCLUSIONS: Oral supplementation with inorganic nitrate did not improve glucose and insulin responses but reduced oxidative stress in old individuals during acute hyperglycemia. This trial was registered at www.controlled-trials.com as ISRCTN42776917.

On the use of 31P NMR for the quantification of hydrosoluble phosphorus-containing compounds in coral host tissues and cultured zooxanthellae.

(31)P Nuclear Magnetic Resonance (NMR) was assessed to investigate the phosphorus-containing compounds present in the tissues of the scleractinian coral Stylophora pistillata as well as of cultured zooxanthellae (CZ). Results showed that phosphorus-containing compounds observed in CZ were mainly phosphate and phosphate esters. Phosphate accounted for 19 ± 2% of the total phosphorus compounds observed in CZ maintained under low P-levels (0.02 µM). Adding 5 mM of dissolved inorganic phosphorus (KH2PO4) to the CZ culture medium led to a 3.1-fold increase in intracellular phosphate, while adding 5 mM of dissolved organic phosphorus led to a reduction in the concentration of phosphorus compounds, including a 2.5-fold intracellular phosphate decrease. In sharp contrast to zooxanthellae, the host mainly contained phosphonates, and to a lesser extent, phosphate esters and phosphate. Two-months of host starvation decreased the phosphate content by 2.4 fold, while bleaching of fed corals did not modify this content. Based on (31)P NMR analyses, this study highlights the importance of phosphonates in the composition of coral host tissues, and illustrates the impact of phosphorus availability on the phosphorus composition of host tissues and CZ, both through feeding of the host and inorganic phosphorus enrichment of the CZ.

Effects of Halide Ions on the Carbamidocyclophane Biosynthesis in Nostoc sp. CAVN2.

In this study, the influence of halide ions on [7.7]paracyclophane biosynthesis in the cyanobacterium Nostoc sp. CAVN2 was investigated. In contrast to KI and KF, supplementation of the culture medium with KCl or KBr resulted not only in an increase of growth but also in an up-regulation of carbamidocyclophane production. LC-MS analysis indicated the presence of chlorinated, brominated, but also non-halogenated derivatives. In addition to 22 known cylindrocyclophanes and carbamidocyclophanes, 27 putative congeners have been detected. Nine compounds, carbamidocyclophanes M-U, were isolated, and their structural elucidation by 1D and 2D NMR experiments in combination with HRMS and ECD analysis revealed that they are brominated analogues of chlorinated carbamidocyclophanes. Quantification of the carbamidocyclophanes showed that chloride is the preferably utilized halide, but incorporation is reduced in the presence of bromide. Evaluation of the antibacterial activity of 30 [7.7]paracyclophanes and related derivatives against selected pathogenic Gram-positive and Gram-negative bacteria exhibited remarkable effects especially against methicillin- and vancomycin-resistant staphylococci and Mycobacterium tuberculosis. For deeper insights into the mechanisms of biosynthesis, the carbamidocyclophane biosynthetic gene cluster in Nostoc sp. CAVN2 was studied. The gene putatively coding for the carbamoyltransferase has been identified. Based on bioinformatic analyses, a possible biosynthetic assembly is discussed.

Glucocorticoid activity and metabolism with NaCl-induced low-grade metabolic acidosis and oral alkalization: results of two randomized controlled trials.

Low-grade metabolic acidosis (LGMA), as induced by high dietary acid load or sodium chloride (NaCl) intake, has been shown to increase bone and protein catabolism. Underlying mechanisms are not fully understood, but from clinical metabolic acidosis interactions of acid-base balance with glucocorticoid (GC) metabolism are known. We aimed to investigate GC activity/metabolism under alkaline supplementation and NaCl-induced LGMA. Eight young, healthy, normal-weight men participated in two crossover designed interventional studies. In Study A, two 10-day high NaCl diet (32 g/d) periods were conducted, one supplemented with 90 mmol KHCO3/day. In Study B, participants received a high and a low NaCl diet (31 vs. 3 g/day), each for 14 days. During low NaCl, the diet was moderately acidified by replacement of a bicarbonate-rich mineral water (consumed during high NaCl) with a non-alkalizing drinking water. In repeatedly collected 24-h urine samples, potentially bioactive-free GCs (urinary-free cortisol + free cortisone) were analyzed, as well as tetrahydrocortisol (THF), 5α-THF, and tetrahydrocortisone (THE). With supplementation of 90 mmol KHCO3, the marker of total adrenal GC secretion (THF + 5α-THF + THE) dropped (p = 0.047) and potentially bioactive-free GCs were reduced (p = 0.003). In Study B, however, GC secretion and potentially bioactive-free GCs did not exhibit the expected fall with NaCl-reduction as net acid excretion was raised by 30 mEq/d. Diet-induced acidification/alkalization affects GC activity and metabolism, which in case of long-term ingestion of habitually acidifying western diets may constitute an independent risk factor for bone degradation and cardiometabolic diseases.