Nitrate alleviates ammonium toxicity in Brassica napus by coordinating rhizosphere and cell pH and ammonium assimilation.

In natural and agricultural situations, ammonium ( NH 4 + ) is a preferred nitrogen (N) source for plants, but excessive amounts can be hazardous to them, known as NH 4 + toxicity. Nitrate ( NO 3 - ) has long been recognized to reduce NH 4 + toxicity. However, little is known about Brassica napus, a major oil crop that is sensitive to high NH 4 + . Here, we found that NO 3 - can mitigate NH 4 + toxicity by balancing rhizosphere and intracellular pH and accelerating ammonium assimilation in B. napus. NO 3 - increased the uptake of NO 3 - and NH 4 + under high NH 4 + circumstances by triggering the expression of NO 3 - and NH 4 + transporters, while NO 3 - and H+ efflux from the cytoplasm to the apoplast was enhanced by promoting the expression of NO 3 - efflux transporters and genes encoding plasma membrane H+ -ATPase. In addition, NO 3 - increased pH in the cytosol, vacuole, and rhizosphere, and down-regulated genes induced by acid stress. Root glutamine synthetase (GS) activity was elevated by NO 3 - under high NH 4 + conditions to enhance the assimilation of NH 4 + into amino acids, thereby reducing NH 4 + accumulation and translocation to shoot in rapeseed. In addition, root GS activity was highly dependent on the environmental pH. NO 3 - might induce metabolites involved in amino acid biosynthesis and malate metabolism in the tricarboxylic acid cycle, and inhibit phenylpropanoid metabolism to mitigate NH 4 + toxicity. Collectively, our results indicate that NO 3 - balances both rhizosphere and intracellular pH via effective NO 3 - transmembrane cycling, accelerates NH 4 + assimilation, and up-regulates malate metabolism to mitigate NH 4 + toxicity in oilseed rape.

Photodegradation of glyphosate in water and stimulation of by-products on algae growth.

Glyphosate is the most widely used herbicide in global agricultural cultivation. However, little is known about the environmental risks associated with its migration and transformation. We conducted light irradiation experiments to study the dynamics and mechanism of photodegradation of glyphosate in ditches, ponds and lakes, and evaluated the effect of glyphosate photodegradation on algae growth through algae culture experiments. Our results showed that glyphosate in ditches, ponds and lakes could undergo photochemical degradation under sunlight irradiation with the production of phosphate, and the photodegradation rate of glyphosate in ditches could reach 86% after 96 h under sunlight irradiation. Hydroxyl radicals (•OH) was the main reactive oxygen species (ROS) for glyphosate photodegradation, and its steady-state concentrations in ditches, ponds and lakes were 6.22 × 10-17, 4.73 × 10-17, and 4.90 × 10-17 M. The fluorescence emission-excitation matrix (EEM) and other technologies further indicated that the humus components in dissolved organic matter (DOM) and nitrite were the main photosensitive substances producing •OH. In addition, the phosphate generated by glyphosate photodegradation could greatly promote the growth of Microcystis aeruginosa, thereby increasing the risk of eutrophication. Thus, glyphosate should be scientifically and reasonably applied to avoid environmental risks.

Surgical treatment of children Graves' disease with huge goiter-a case report and literature review.

Graves' disease is the most common cause of hyperthyroidism in children. The surgery treatment for children Graves' disease with huge goiter is high risk and controversial. A 14-year-old girl suffered Graves' disease with huge goiter and failed to the antithyroid drug therapy for nearly 4 years was surgically treated with total thyroidectomy. The excised thyroid weighed 449.1 g and heavier than any excised children goiter reported so far. After operation, the patient's symptoms of Graves' disease were significantly improved without any complication, including normal basal metabolic rate, relieved exophthalmia and euthyroidism. So, a children Graves' disease with huge goiter was cured by total thyroidectomy, suggesting that a total/near-total thyroidectomy is a good option for children Graves' disease with huge goiter.

[HPLC fingerprint analysis of acetoacetate extraction of Polygonum orientale].

OBJECTIVE: To establish the HPLC fingerprint analysis method for the quality control of acetoacetate extraction of Polygonum orientale. METHODS: Agilent C18 (4.6 mm x 250 mm, 5 microm); DAD detector; Mobile phase: methyl alcohol-water gradient elution at a flow rate of 1.0 mL/min, and at a column temperature of 30 degrees C. RESULTS: 26 peaks were selected as the common fingerprint peaks. The relative standard deviations for relative retention values were less than 3% in the precision and repeated test. CONCLUSION: The repetition, stability and precision of the method is good and it can be used to control the quality of Polygonum orientale.

[HPLC fingerprint of flavonoids in fruits of Polygonum orientale].

OBJECTIVE: To compare HPLC fingerprint of flavonoids in fruits of Polygonnm orientale from different regions. METHODS: Diamonsil C18 (250 mm x 4.6 mm, 5 microm) had been used, the mobile phase consisted of methanol and 0.2% phosphoric acid as fradient eluent. The flow rate was 1 ml/min, and the detection wavelength was 310 nm. RESULTS: The finerprint of flaxonoids in fruits of Poligonum orientale with 11 common peaks was eatablished. The realative retention time and the range of relative area of the common peaks were determined. CONCLUSION: The established fingerprint can be used for the identification and quality control of flavonoids of Poligonum orientale from different regions.