Carbon-nitrogen trading in symbiotic nodules depends on magnesium import.

Symbiotic nitrogen fixation provides large amounts of nitrogen for global agricultural systems with little environmental or economic costs. The basis of symbiosis is the nutrient exchange occurring between legumes and rhizobia, but key regulators controlling nutrient exchange are largely unknown. Here, we reveal that magnesium (Mg), an important nutrient factor that preferentially accumulates in inner cortical cells of soybean nodules, shows the most positive correlation with nodule carbon (C) import and nitrogen (N) export. We further identified a pair of Mg transporter genes, GmMGT4 and GmMGT5, that are specifically expressed in the nodule cortex, modulating both nodule Mg import and C-N transport processes. The GmMGT4&5-dependent Mg import activates the activity of a plasmodesmata-located ß-1,3-glucanase GmBG2 and consequently keeps plasmodesmata permeable for C-N transport in nodule inner cortical cells. Our studies discovered an important regulating pathway for host plants fine-tuning nodule C-N trading to achieve optimal growth, which may be helpful for optimizing nutrient management for soybean production.

Cooling Kinetic Characteristics of Temperature Difference between Cadaver Temperature and Ambient Temperature.

OBJECTIVES: To study the cooling reaction kinetic characteristics of the temperature difference between cadaver temperature and ambient temperature (hereinafter referred to as "cadaver temperature difference") according to the reaction kinetics method. METHODS: Thirty rabbits were randomly divided into 5 groups with 6 rabbits in each group. The rabbits were injected with 10% potassium chloride solution intravenously. After death, the rabbits were placed at 5 ℃, 10 ℃, 15 ℃, 20 ℃ and 25 ℃ environment condition, respectively, and the rectal temperature was measured every minute for 20 hours. The measured cadaver temperature was subtracted from ambient temperature, and the cadaver temperature difference data was calculated using the reaction kinetics formula. The linear regression equation was fitted for analysis, and the experimental results were applied to the temperature difference data of human body after death for verification. RESULTS: Under different environmental conditions, the linear coefficient determination of temperature difference -ln(C/C0) in rabbits was 0.99, showing a good linear relationship with time t. The application of human body temperature data after death was consistent with the results of animal experiments. CONCLUSIONS: Under stable conditions, the temperature difference cooling process after death in rabbits is a first-order kinetic response. The method can also be used to study the temperature difference in human body after death.

Selection for Anti-transferrin Receptor Bispecific T-cell Engager in Different Molecular Formats.

Selecting an ideal molecular format from diverse structures is a major challenge in developing a bispecific antibody (BsAb). To choose an ideal format of anti-CD3 × anti-transferrin receptor (TfR) bispecific antibodies for clinical application, we constructed TfR bispecific T-cell engager (BiTE) in two extensively applied formats, including single-chain tandem single-chain variable fragments (scFvs) and double-chain diabodies, and evaluated their functional characterizations in vitro. Results demonstrated that TfR-BiTE in both formats directed potent killing of TfR+ HepG2 cells. However, compared to two-chain diabodies, scFvs were more efficient in antigen binding and TfR+ target killing. Furthermore, different domain orders in scFvs would also be evaluated because single-TfR-CD3-His was preferable to single-CD3-TfR-His in immunotherapeutic strategies. Thus, the single-chain tandem TfR-CD3 format was favored for further investigation in cancer therapy.