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Your search keyword '"Xu Nianjun"' showing total 264 results
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264 results on '"Xu Nianjun"'

30. Physiological, Transcriptome, and Metabolome Analyses Reveal the Tolerance to Cu Toxicity in Red Macroalgae Gracilariopsis lemaneiformis.

Author

Chen, Xiaojiao, Tang, Yueyao, Zhang, Hao, Zhang, Xiaoqian, Sun, Xue, Zang, Xiaonan, and Xu, Nianjun

Subjects
COPPER, MARINE algae, EICOSAPENTAENOIC acid, ATP-binding cassette transporters, TRANSCRIPTOMES, HEAVY metals, SUPEROXIDES
Abstract

Heavy metal copper (Cu) will inevitably impact the marine macroalgae Gracilariopsis lemaneiformis (G. lemaneiformis), which is a culture of economic importance along China's coastline. In this study, the detoxification mechanism of Cu stress on G. lemaneiformis was revealed by assessing physiological indicators in conjunction with transcriptome and metabolome analyses at 1 d after Cu stress. Our findings revealed that 25 μM Cu stimulated ROS synthesis and led to the enzymatic oxidation of arachidonic acid residues. This process subsequently impeded G. lemaneiformis growth by suppressing photosynthesis, nitrogen metabolism, protein synthesis, etc. The entry of Cu ions into the algae was facilitated by ZIPs and IRT transporters, presenting as Cu2+. Furthermore, there was an up-regulation of Cu efflux transporters HMA5 and ABC family transporters to achieve compartmentation to mitigate the toxicity. The results revealed that G. lemaneiformis elevated the antioxidant enzyme superoxide dismutase and ascorbate-glutathione cycle to maintain ROS homeostasis. Additionally, metabolites such as flavonoids, 3-O-methylgallic acid, 3-hydroxy-4-keto-gama-carotene, and eicosapentaenoic acid were up-regulated compared with the control, indicating that they might play roles in response to Cu stress. In summary, this study offers a comprehensive insight into the detoxification mechanisms driving the responses of G. lemaneiformis to Cu exposure. [ABSTRACT FROM AUTHOR]

Published
2024
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46. Characterization of monogalactosyldiacylglycerol synthases in Gracilariopsis lemaneiformis and their potential roles in the fading of the thallus.

Author

Zhang, Li, Yuan, Quan, Hu, Chaoyang, Sun, Xue, Gong, Yifu, and Xu, Nianjun

Subjects
UNSATURATED fatty acids, SYNTHASES, PHOTOSYNTHETIC pigments, PRINCIPAL components analysis, FATTY acids, MEMBRANE lipids, CHLOROPHYLL spectra
Abstract

Membrane lipids play essential roles in regulating physiological properties in higher plants and algae. Monogalactosyldiacylglycerol (MGDG) is a major thylakoid membrane lipid, and it is an important source of polyunsaturated fatty acids for cells, plays a key role in the biogenesis of plastids, and maintains the function of the photosynthetic machinery. Several studies have indicated that the knockdown of MGDG synthase results in membrane lipid remodeling, albino seedlings, and changes in photosynthetic performance. However, the effects of MGDG synthase (MGD) inhibitors on lipids in macroalgae have not yet been clarified. Here, we characterized the effects of MGD inhibitors (ortho‐phenanthroline and N‐ethylmaleimide) on the composition of the fatty acids observed in MGDG and digalactosyldiacylglycerol (DGDG) in Gracilariopsis lemaneiformis using electrospray ionization–mass spectrometry. The most abundant MGDG species contained 16:0/18:1 (sn‐1/sn‐2) fatty acids, and the most dominant DGDG species contained 20:5/16:0 (sn‐1/sn‐2) fatty acids. Measurements of photosynthetic pigments and photosynthetic parameters revealed that photosynthesis of G. lemaneiformis was impaired. Principal component analysis and Spearman's correlation analysis revealed interactions between specific MGDG structural composition patterns and key metabolites involved in photosynthesis, indicating that 20:4/16:0 (sn‐1/sn‐2) MGDG and 16:0/18:1 (sn‐1/sn‐2) MGDG affect the structure and function of phycobilisomes and thus the color of G. lemaneiformis. Three genes (GlMGD1, GlMGD2, and GlMGD3) were cloned and identified. The addition of N‐ethylmaleimide to G. lemaneiformis did not affect the abundance of GlMGD mRNA, and the abundance of transcripts was significantly decreased by ortho‐phenanthroline. [ABSTRACT FROM AUTHOR]

Published
2023
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50. Additional file 1 of A survey of the full-length transcriptome of Gracilariopsis lemaneiformis using single-molecule long-read sequencing

Author

Chen, Xiaojiao, Tang, Yue Yao, Yin, Haodong, Sun, Xue, Zhang, Xiaoqian, and Xu, Nianjun

Abstract

Additional file 1: Figure S1. The alignment rate between unique transcripts from SMRT-Seq and sequences from RNA-Seq. Figure S2. Alternative splicing (AS) (A-E) and alternative polyadenylation (APA) (F) event types. (A) Exon skipping (ES); (B) retention of introns (IR); (C) alternative exon ends (AE); (D) alternative transcription start site (TSS); and (E) alternative transcription termination site (TTS). AS features are in red. (F) APA event types. Figure S3. Sequences of the AS transcripts and their corresponding genes. Figure S4. The enriched GO categories and KEGG pathways of the transcripts with DAS events under Cu and Cu + ACC conditions. Figure S5. Uncropped images PCR of validation of AS events used to prepare Fig. 3. Figure S6. Uncropped images PCR of validation of APA events used to prepare Fig. 4C. Figure S7. Uncropped images PCR of validation of miRNAs used to prepare Fig. 5.

Published
2023
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