Climate extremes drive the phenology of a dominant species in meadow steppe under gradual warming.

Plant phenology in terrestrial ecosystems, especially in the Northern Hemisphere, is expected to change owing to the projected increasing frequency and intensity of climate extremes in the context of global warming. Although such changes under mean climate change have been extensively reported in the literature, little is known about the impacts of climate extremes. In this study, climatic changes and their effects on plant phenology were characterized using long-term climatic and phenological data from the start and end of the growing season (SOS and EOS, respectively) from 2005 to 2020 for Stipa baicalensis, a dominant species in a temperate meadow steppe. The results showed that the temperature, including the mean and minimum temperatures, and extreme warm indices significantly increased; however, annual precipitation, and the frequency of extreme cold and precipitation events decreased. The SOS of S. baicalensis was initially earlier and later, whereas the EOS trended to be delayed. However, the growing season (LOS) was slightly prolonged. Compared with the indices under mean temperature, the pre-season (before SOS or EOS) minimum temperature dominantly affected SOS and EOS, whereas the mean and extreme precipitation slightly affected them. Furthermore, the findings showed that plant phenology responded to extreme temperatures quicker and stronger than mean temperatures. This study provides insight into how key extreme climatic factors could affect plant phenophases and improve and refine the phenological model. This could also be useful in enhancing grassland ecosystem management and sustainable development.

Therapeutic effect of chemokine SLC combined with immune adjuvant CpG-ODN in treatment of implanted mouse melanoma / 中国肿瘤生物治疗杂志

Objective: To study the therapeutic effect of secondary lymphoid tissue chemokine (SLC) combined with CpG oligodeoxynucleotide (CpG-ODN) in treatment of implanted mouse melanoma and the possible mechanism. Methods: SLC-Fc fusion protein was prepared and its chemotaxis of lymphocytes was detected by chemotaxis assay. Implanted melanoma mouse models were established and randomly divided into 4 groups: control group, SLC-Fc group, CpG-ODN group, and SLC-Fc+CpG-ODN group. The growth of implanted tumors in each group was observed after treatment. Subtype and infiltration of lymphocytes in implanted tumor tissues were examined by flow cytometry. Results: SLC-Fc protein was successfully prepared, and it dose-dependently attracted lymphocytes (0.03, 0.3, and 3 μg/L). Intra-tumor injection SLC-Fc and CpG-ODN alone or in combination significantly inhibited growth of B16-implanted tumors. Tumor size in SLC-Fc+CpG-ODN group was significantly smaller than that in control group (P<0.01), and animals in SLC-Fc+CpG-ODN group survived longer. Tumor-infiltrated CD4~+ T, CD~8+ T, and dendritic cells (DCs) in SLC-Fc+CpG-ODN group were markedly increased as compared with those in control group (P<0.05), and tumor draining lymph nodes were dramatically enlarged. Conclusion: SLC combined with CpG-ODN can inhibit the growth of implanted melanoma by attracting CD4~+ T and CD8~+ T and promoting proliferation of DCs.