Sphingolipids are ubiquitous in eukaryotes and certain prokaryotes, where they serve as vital components of biological membranes and as bioactive molecules. Chloroplasts have complex membrane structures that play crucial roles in photosynthesis, but their specific sphingolipidome remains unreported. In this study, we used high-performance liquid chromatography-mass spectrometry (HPLC-MS/MS) to analyze the sphingolipidome of purified Arabidopsis thaliana chloroplasts. We detected 92 chloroplast sphingolipids. The chloroplast sphingolipidome differed from total leaf (TL) samples, having a higher content of free long-chain bases and hydroxyceramides, and a greater proportion of complex sphingolipids with 16C fatty acid (FA) forms. Notably, chloroplast glucosylceramides were predominantly the d18:1 h16:0 and t18:1 h16:0 forms, rather than the 24C FA form found in TL and other cellular structures. Comparing the sphingolipidomes of different cellular structures underscores the inhomogeneity of intracellular distribution of sphingolipids. This provides a robust reference for further elucidating the function of sphingolipids in plant cells.

This study investigated the mechanical properties and fatigue behavior of FH36 steel plate rolled in different directions. By adopting a sequential rolling process in the rolling direction (RD) and transverse direction (TD), the differences in properties between RD and TD were eliminated, resulting in nearly identical tensile properties. The steel plate exhibited a yield strength of approximately 420 MPa, a tensile strength of approximately 506 MPa, and an elongation of approximately 25%. Fatigue tests conducted at room temperature and -60℃ showed a fatigue limit of the maximum stress of 488 MPa at room temperature and 500 MPa at -60℃, indicating improved low-temperature fatigue performance. The fracture surfaces displayed distinct characteristics, such as oblique shearing fractures for high-cycle fatigue and cup-cone shape fractures for low-cycle fatigue. The fatigue source zone were both on the surface of the specimens. As the maximum stress increased, the area of the crack propagation zone for high-cycle fatigue decreased, while the area of the final fracture zone, the number of dimples and the proportion of the LAGBs increased.

Abstract: Transcription factors are crucial pre-transcriptional regulatory mechanisms that can modulate the expression of downstream genes by binding to their promoter regions. DOF (DNA binding with One Finger) proteins are a unique class of transcription factors with extensive roles in plant growth and development. Our previous research indicated a decrease in iron content in chlorotic bamboo leaves. However, to our knowledge, genes related to iron metabolism pathways in bamboo species have not yet been studied. Therefore, in the current study, we identified iron metabolism-related (IMR) genes in bamboo and determined the transcription factors that significantly influence them. Among these, DOFs were found to have widespread effects and potentially significant impacts on their expression. We identified specific DOF members in Dendrocalamus latiflorus with binding abilities through homology with Arabidopsis DOF proteins, and established connections between some of these members and IMR genes using RNA-seq data. Additionally, molecular docking confirmed the binding interactions between these DlDOFs and the DOF binding sites in the promoter regions of IMR genes. The co-expression relationship between the two gene sets was further validated using q-PCR experiments. This study paves the way for research into iron metabolism pathways in bamboo and lays the foundation for understanding the role of DOF transcription factors in D. latiflorus.