Metal nutrition and transport in the process of symbiotic nitrogen fixation.

Symbiotic nitrogen fixation (SNF) facilitated by the interaction between legumes and rhizobia is a well-documented and eco-friendly alternative to chemical nitrogen fertilizers. Host plants obtain fixed nitrogen from rhizobia by providing carbon and mineral nutrients. These mineral nutrients, which are mostly in the form of metal ions, are implicated in various stages of the SNF process. This review describes the functional roles played by metal ions in nodule formation and nitrogen fixation and specifically addresses their transport mechanisms and associated transporters within root nodules. Future research directions and potential strategies for enhancing SNF efficiency are also discussed.

Two central circadian oscillators OsPRR59 and OsPRR95 modulate magnesium homeostasis and carbon fixation in rice.

Photosynthesis, which provides oxygen and energy for all living organisms, is circadian regulated. Photosynthesis-associated metabolism must tightly coordinate with the circadian clock to maximize the efficiency of the light-energy capture and carbon fixation. However, the molecular basis for the interplay of photosynthesis and the circadian clock is not fully understood, particularly in crop plants. Here, we report two central oscillator genes of circadian clock, OsPRR95 and OsPRR59 in rice, which function as transcriptional repressors to negatively regulate the rhythmic expression of OsMGT3 encoding a chloroplast-localized Mg2+ transporter. OsMGT3-dependent rhythmic Mg fluctuations modulate carbon fixation and consequent sugar output in rice chloroplasts. Furthermore, sugar triggers the increase of superoxide, which may act as a feedback signal to positively regulate the expression of OsPRR95 and OsPRR59. Taken together, our results reveal a negative-feedback loop that strengthens the crosstalk between photosynthetic carbon fixation and the circadian clock, which may improve plan adaptation and performance in fluctuating environments.

[Clinical experience of successful management of a child with A/H5N1 infection in Shanxi province].

OBJECTIVE: To explore the clinical features and treatment strategy of human influenza A (H5N1) virus infection. METHODS: The clinical data from a 2-year-old girl with A/H5N1 infection were collected and analyzed. RESULTS: The patient had a history of exposure to a living poultry market. A/H5N1 nucleic acid was detected by real-time polymerase chain reaction and reverse-transcription polymerase chain reaction in a nasopharyngeal aspirate. The prominent clinical features included fever, cough and dyspnea. Extensive multiple lobular infiltrates developed quickly, followed by acute respiratory distress syndrome (ARDS) and multi-organ dysfunction. Corticosteroids, oxygen therapy and non-invasive mechanical ventilation were administrated on day 9 after onset of the disease. The patient's condition became stable after the management. After A/H5N1 infection was confirmed, antiviral treatment with oseltamivir and A/H5N1 vaccinated plasma were used on day 11. Oxygenation and serum enzyme levels returned to normal gradually, and most of the lung infiltrates disappeared. The patient was discharged on day 28. CONCLUSION: Human A/H5N1 infection is a severe and rapidly progressive disease mostly manifested as ARDS. Corticosteroids may have some effects on the pulmonary lesions, but oxygen therapy and ventilatory support are the mainstay of the management. A/H5N1 vaccinated plasma may be useful for improving the prognosis.