Hao LI

Oct 20, 2024 | nature.com | Minjia Zheng |Xinlan Chen |Hao LI |Wei Zheng |Feng Guo |Laiting Si | +3 more

The low cultivability of environmental bacteria has been widely acknowledged, but most previous estimates focused on the proportion of cultivable cells rather than cultivable taxa. Here, we estimate the proportions of cultivable cells and cultivable taxa for two sample types (soil and activated sludge) using cell counting, 16S rRNA gene amplicon sequencing, metagenomics, and cultivation on agar plates under various conditions. We find that the proportion of cultivable taxa exceeds that of cultivable cells at the sample level. A large proportion of cultivable taxa are taxonomically novel but tend to be present at very low abundance on agar plates, forming microcolonies, and some of them cease to grow during subculture. Compared with uncultivable taxa (under the conditions used in our study), cultivatable taxa tend to display higher metabolic activity as inferred by measuring rRNA copies per cell. Finally, we use the generated taxonomic and genomic information as a guide to isolate a strain representing a yet-uncultured class within the Bacteroidota and to enhance the cultivable diversity of Burkholderiales from activated sludge. The low cultivability of most environmental bacteria is well known, but previous estimates focused on the proportion of cultivable cells. Here, the authors use various techniques to show, for soil and activated sludge samples, that the proportion of cultivable taxa exceeds that of cultivable cells, and identify genetic and physiological traits associated with cultivability.

Oct 10, 2024 | nature.com | Hao LI |Mi Xu |Wei-Yew Chang |Linhan Feng

Exploring farmers’ willingness to pay (WTP) for cultivated land protection and its influencing factors is key to promoting their enthusiasm for participating in cultivated land pollution governance. However, existing studies often overlook the differences in farmers’ preference for different levels of cultivated land attributes and the issue of intertemporal choice in farmers’ WTP, thus lowering the effectiveness of cultivated land protection policies. Using survey data from 646 small farmers in Shandong, Jiangsu, and Zhejiang provinces of China, this study empirically analyzes the impact of time preference on farmers’ WTP for cultivated land attribute levels by utilizing the choice experiment method, measures the relative importance of different cultivated land attributes and attribute levels to farmers, and calculates farmers’ WTP for different cultivated land attribute levels. The results revealed that farmers are generally reluctant to pay for cultivated land protection. Time preference affects farmers’ WTP for different levels of cultivated land attributes, with future-biased preference increasing farmers’ WTP and present-biased preference inhibiting it. Furthermore, for farmers, the relative importance of cultivated land attributes is in the order of cultivated land quality, cultivated land surrounding landscape and ecological environment, cultivated land social security function, and cultivated land area. The most crucial cultivated land attribute level is the improved cultivated land quality, with an average WTP of 3290.625 CNY per hectare (approximately 459.117 USD). In contrast, the least important cultivated land attribute level is the unchanged cultivated land area, with an average WTP of 1001.250 CNY per hectare (approximately 139.697 USD). The economic benefits of cultivated land protection in the sampled provinces can reach 353.892 million CNY per year (approximately 49.376 million USD) annually, which is calculated based on vegetable planting area. Our results suggest that the government should diversify farmers’ sources of income while increasing the amount of income, thereby reducing barriers to farmers’ payment. Simultaneously, farmers’ time preferences should be considered to guide them toward expecting long-term benefits and encouraging their active participation in cultivated land pollution governance. Moreover, cultivated land protection policies should match the preference of farmers for cultivated land attributes and attribute levels, and a limited fiscal fund should be allocated to the cultivated land attributes (i.e., cultivated land quality) and attribute levels (i.e., improved cultivated land quality) preferred by farmers to improve policy efficiency. This study highlights the importance of encouraging farmers to actively participate in cultivated land pollution governance and improving the allocation efficiency of the government’s cultivated land protection fund.

Jul 15, 2024 | nature.com | Gang Zhang |Hao LI |Bin Wang |Lu Zhou |Lun Fang |Zhongzhe Li | +2 more

Steroid-induced osteonecrosis of the femoral head (SONFH) is the predominant cause of non-traumatic osteonecrosis of the femoral head (ONFH). Impaired blood supply and reduced osteogenic activity of the femoral head are the key pathogenic mechanisms of SONFH. Fibroblast growth factor 23 (FGF23) levels are not only a biomarker for early vascular lesions caused by abnormal mineral metabolism, but can also act directly on the peripheral vascular system, leading to vascular pathology. The aim of this study was to observe the role of FGF23 on bone microarchitecture and vascular endothelium, and to investigate activation of pyroptosis in SONFH. Lipopolysaccharide (LPS) combined with methylprednisolone (MPS) was applied for SONFH mouse models, and adenovirus was used to increase or decrease the level of FGF23. Micro-CT and histopathological staining were used to observe the structure of the femoral head, and immunohistochemical staining was used to observe the vascular density. The cells were further cultured in vitro and placed in a hypoxic environment for 12 h to simulate the microenvironment of vascular injury during SONFH. The effect of FGF23 on osteogenic differentiation was evaluated using alkaline phosphatase staining, alizarin red S staining and expression of bone formation-related proteins. Matrigel tube formation assay in vitro and immunofluorescence were used to detect the ability of FGF23 to affect endothelial cell angiogenesis. Steroids activated the pyroptosis signaling pathway, promoted the secretion of inflammatory factors in SONFH models, led to vascular endothelial dysfunction and damaged the femoral head structure. In addition, FGF23 inhibited the HUVECs angiogenesis and BMSCs osteogenic differentiation. FGF23 silencing attenuated steroid-induced osteonecrosis of the femoral head by inhibiting the pyroptosis signaling pathway, and promoting osteogenic differentiation of BMSCs and angiogenesis of HUVECs in vitro.

Dec 28, 2023 | pubs.rsc.org | Hao LI |Ke Fan |Pei Xiong |Zezhou Lin |Hanmo Zhou

Selective Grafting of Phosphorus onto Ti3C2Tx MXene Enables Two-Proton Process and Enhanced Charge Storage Ti3C2Tx MXene shows great promise as a supercapacitor electrode material owing to its high conductivity and pseudocapacitive nature. Phosphorus doping is an efficient strategy to boost its capacitance due to synergistic effect of the P-O and P-C species formed.