scholarly journals Regulation of Glutamine Synthetase by Light and during Nitrogen Deficiency in Synchronous Chlorella sorokiniana

1980 ◽  
Vol 66 (5) ◽  
pp. 805-808 ◽  
Author(s):  
Rudolf Tischner ◽  
Aloys Hüttermann
2021 ◽  
Vol 22 (14) ◽  
pp. 7674
Author(s):  
Ting Liang ◽  
Zhengqing Yuan ◽  
Lu Fu ◽  
Menghan Zhu ◽  
Xiaoyun Luo ◽  
...  

Nitrogen (N) is an essential nutrient for plant growth and development. The root system architecture is a highly regulated morphological system, which is sensitive to the availability of nutrients, such as N. Phenotypic characterization of roots from LY9348 (a rice variety with high nitrogen use efficiency (NUE)) treated with 0.725 mM NH4NO3 (1/4N) was remarkable, especially primary root (PR) elongation, which was the highest. A comprehensive analysis was performed for transcriptome and proteome profiling of LY9348 roots between 1/4N and 2.9 mM NH4NO3 (1N) treatments. The results indicated 3908 differential expression genes (DEGs; 2569 upregulated and 1339 downregulated) and 411 differential abundance proteins (DAPs; 192 upregulated and 219 downregulated). Among all DAPs in the proteome, glutamine synthetase (GS2), a chloroplastic ammonium assimilation protein, was the most upregulated protein identified. The unexpected concentration of GS2 from the shoot to the root in the 1/4N treatment indicated that the presence of an alternative pathway of N assimilation regulated by GS2 in LY9348 corresponded to the low N signal, which was supported by GS enzyme activity and glutamine/glutamate (Gln/Glu) contents analysis. In addition, N transporters (NRT2.1, NRT2.2, NRT2.3, NRT2.4, NAR2.1, AMT1.3, AMT1.2, and putative AMT3.3) and N assimilators (NR2, GS1;1, GS1;2, GS1;3, NADH-GOGAT2, and AS2) were significantly induced during the long-term N-deficiency response at the transcription level (14 days). Moreover, the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis demonstrated that phenylpropanoid biosynthesis and glutathione metabolism were significantly modulated by N deficiency. Notably, many transcription factors and plant hormones were found to participate in root morphological adaptation. In conclusion, our study provides valuable information to further understand the response of rice roots to N-deficiency stress.


2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Ruijuan Ma ◽  
Zhen Zhang ◽  
Zhuzhen Tang ◽  
Shih-Hsin Ho ◽  
Xinguo Shi ◽  
...  

AbstractCo-production of multiple compounds is an efficient approach to enhance the economic feasibility of microalgae-based metabolites production. In this study, Chlorella sorokiniana FZU60 was cultivated under different bioprocess strategies to enhance the co-production of lutein and protein. Results showed that both lutein and protein content (7.72 and 538.06 mg/g, respectively) were highest at the onset of nitrogen deficiency under batch cultivation. Semi-batch III strategy, with 75% microalgal culture replacement by fresh medium, obtained similar content, productivity, and yield of lutein and protein as batch cultivation, demonstrating that it can be used for stable and continuous production. Fed-batch II strategy, feeding with 1/3 modified BG11 medium, achieved super-high lutein and protein yield (28.81 and 1592.77 mg/L, respectively), thus can be used for high-output production. Besides, two-stage strategy, combining light intensity shift and semi-batch cultivation, gained extremely high lutein and protein productivity (15.31 and 1080.41 mg/L/day, respectively), thereby is a good option for high-efficiency production. Moreover, the fed-batch II and two-stage strategy achieved high-quality lutein and protein, thus are promising for the co-production of lutein and protein in C. sorokiniana FZU60 for commercial application.


Author(s):  
W. Kunath ◽  
E. Zeitler ◽  
M. Kessel

The features of digital recording of a continuous series (movie) of singleelectron TV frames are reported. The technique is used to investigate structural changes in negatively stained glutamine synthetase molecules (GS) during electron irradiation and, as an ultimate goal, to look for the molecules' “undamaged” structure, say, after a 1 e/Å2 dose.The TV frame of fig. la shows an image of 5 glutamine synthetase molecules exposed to 1/150 e/Å2. Every single electron is recorded as a unit signal in a 256 ×256 field. The extremely low exposure of a single TV frame as dictated by the single-electron recording device including the electron microscope requires accumulation of 150 TV frames into one frame (fig. lb) thus achieving a reasonable compromise between the conflicting aspects of exposure time per frame of 3 sec. vs. object drift of less than 1 Å, and exposure per frame of 1 e/Å2 vs. rate of structural damage.


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