Exploring the ecological meanings of temperature sensitivity of ecosystem respiration from different methods.

Temperature sensitivity (Q10) of ecosystem respiration (Re) is a critical parameter for predicting global terrestrial carbon dynamics and its response to climate warming. However, the determination of Q10 has been controversial. In this study, we scrutinized the underpinnings of three mainstream methods to reveal their relationships in estimating Q10 for Re in the Heihe River Basin, northwest China. Specifically, these methods are Q10 estimated from the long-term method (Q10_long), short-term method (Q10_short), and the low-frequency (Q10_lf) and high-frequency (Q10_hf) signals decomposed by the singular spectrum analysis (SSA) method. We found that: 1) Q10_lf and Q10_long are affected by the confounding effects caused by non-temperature factors, and are 1.8 ± 0.3 and 1.7 ± 0.3, respectively. 2) The high-frequency signals of the SSA method and short-term method have consistent roles in removing the confounding effects. Both Q10_short and Q10_hf reflect the actual response of respiration to temperature. 3) Overall, Q10_long has a larger variability (1.7 ± 0.3) across different biomes, whereas Q10_short and Q10_hf show convergence (1.4 ± 0.2 and 1.3 ± 0.1, respectively). These results highlight the fact that Q10 can be overestimated by the long-term method, whereas the short-term method and high-frequency signals decomposed by the SSA method can obtain closer and convergent values after removing the confounding effects driven by non-temperature factors. Therefore, it is recommended to use the Q10 value estimated by the short-term method or high-frequency signals decomposed by the SSA method to predict carbon dynamics and its response to global warming in Earth system models.

[Kiwi fruit essence reduces radiation-induced lung injury by down-regulating TNF-α and PDGF-B in rats].

Objective To observe the role of tumor necrosis factor-α (TNF-α) and platelet-derived growth factor-B (PDGF-B) in kiwi fruit essence-mediated protection of radiation-induced lung injury (RILI) in rats. Methods 96 male healthy Sprague-Dawley rats were divided into normal control group, model group, and kiwi fruit essence treatment group(60 and 240 mg/kg) by the random number table method, with 24 animals in each group. The whole lungs underwent 6 MV X-ray irradiation (18 Gy) to induce RILI animal models in rats of the latter three groups. On the next day after irradiation, rats in the latter two groups were intragastrically administrated with 60 or 240 mg/kg kiwi fruit essence, once a day. The rats in the normal control and model groups were treated with 9 g/L sodium chloride solution. Eight rats in the latter three groups were randomly sacrificed on days 14, 28, and 56, while normal control rats were sacrificed on day 56 as the overall control. Blood samples were collected and separated. Serum concentrations of TNF-α and PDGF-B were detected using ELISA. The lung tissues were isolated for HE and Masson staining to evaluate alveolitis and pulmonary fibrosis (PF). The hydroxyproline (HYP) content in lung tissues was detected. The mRNA and protein expression of pulmonary TNF-α and PDGF-B were determined by quantitative real-time PCR and immunohistochemistry. Results Compared with the model group, treatment with 60 and 240 mg/kg kiwi fruit essence group significantly reduced alveolitis on days 14 and 28 as well as PF lesions on days 28 and 56. Compared with the normal control group, HYP content in the lung tissue of the model group increased on day 28 and day 56, while TNF-α and PDGF-B levels in the serum and lung tissues increased at each time point. Compared with the model group during the same period, 60 and 240 mg/kg kiwi fruit essence element treatment group reported the diminished levels of serum and pulmonary TNF-α on day 14 and day 28. Consistently, the lung tissue HYP content and serum and pulmonary PDGF-B levels on day 28 and day 56 were reduced. In addition, the above indicators in the 240 mg/kg kiwi fruit essence treatment group were lower than those for the 60 mg/kg kiwi fruit essence treatment group. Conclusion Kiwi fruit essence can alleviate RILI in rats, which is related to the down-regulation of TNF-α expression at the early stage and decreased PDGF-B level at the middle and late stages.

[Unsaturated fatty acid of Actinidia chinesis planch seed oil protects against pulmonary fibrosis by inhibiting collagen synthesis via down-regulating connective tissue growth factor (CTGF) expression in rats].

Objective To observe the role of connective tissue growth factor (CTGF) and collagen synthesis in anti-pulmonary fibrosis (PF) by Kiwi fruit essence(unsaturated fatty acid of actinidia chinesis planch seed oil)in rats. Methods Sixty male SD rats were randomly divided into control group, model group, Kiwi fruit essence (60, 120, 240 mg/kg) treatment groups, and 5 mg/kg prednisone acetate group, with 10 animals in each group. Rats in control group were intratracheally administered with 9 g/L sodium chloride solution, and animals in other groups were intratracheally administered with bleomycin A5 to establish PF model. From the second day on, rats in the latter 4 groups were intragastrically treated with Kiwi fruit essence of 60, 120 and 240 mg/kg and prednisone acetate of 5 mg/kg, respectively. Rats in control and model groups were treated with 9 g/L sodium chloride solution once a day. All rats were sacrificed on day 28, and then pulmonary tissues were removed. The extent of PF lesions were evaluated using HE and Masson staining. The contents of hydroxyproline (HYP) were measured by a commercial kit. The mRNA expressions of CTGF and α-smooth muscle actin (α-SMA) in pulmonary tissues was detected by quantitative real-time PCR. The protein expressions of CTGF, α-SMA, collagen type 1 (Col1) and Col3 were measured by Western blotting. The protein levels of CTGF were analyzed using immunohistochemical staining. Results Compared with the model group, the alveolitis and PF extent in 60, 120, 240 mg/kg Kiwi fruit essence treatment groups as well as 5 mg/kg prednisone acetate group were significantly alleviated, and the content of HYP and the expression of CTGF, α-SMA, Col1 and Col3 decreased. The changes of above indicators were dose-dependent among the (60, 120, 240) mg/kg Kiwi fruit essence treatment groups. Moreover, the above indicators were found higher in (60, 120) mg/kg Kiwi fruit essence treatment groups than those in 5 mg/kg prednisone acetate group, which, however, showed no significantly difference between 240 mg/kg Kiwi fruit essence treatment group and 5 mg/kg prednisone acetate group. Conclusion Kiwi fruit essence down-regulates CTGF expression and decreases the levels of α-SMA, leading to inhibition of Col1 and Col3 synthesis and alleviation of PF.

Efficient recovery of a functional extracellular domain of bovine IgG2 Fc receptor (boFcgamma2R) from inclusion bodies by a rapid dilution refolding system.

The extracellular domain of the boFcgamma2R gene was constructed and cloned into the Escherichia coli expression vector pET-28a. The recombinant protein was expressed at high level in E. coli BL21(DE3) and existed mainly as inclusion bodies. The inclusion bodies were solubilized in 6 M guanidine hydrochloride and refolded by rapid dilution. After renaturation, the purity of the recovered recombinant protein was up to 95%. ELISA assay showed that the renatured recombinant protein could inhibit bovine IgG2 binding to expressed boFcgamma2R on the COS-7 cell surface with an IC50 value of 0.68 microM. The overall yield of the active rsbo2R was up to 20 mg/l of culture. Crystals of the rsbo2R were grown at 293 K by the hanging-drop vapour diffusion method showed weak diffraction.