scholarly journals Relationship between β-Carotene Accumulation and Geranylgeranyl Pyrophosphate Synthase in Different Species of Dunaliella

Plants ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 27
Author(s):  
Lu Xu ◽  
Fan Gao ◽  
Jia Feng ◽  
Junping Lv ◽  
Qi Liu ◽  
...  

To study the relationship between β-carotene synthesis and geranylgeranyl pyrophosphate synthase (GGPS) activity, 15 species of Dunaliella were used to determine the changes in photosynthetic pigment contents, chlorophyll fluorescence parameters, β-carotene content, and GGPS activity. By observing the morphology and size of 15 species of Dunaliella, D8 has the largest individual algal cell and D9 has the smallest individual. Growth was relatively slow during days one through seven. After about eight days, the cells entered the logarithmic growth period and grew rapidly to a high density. After about 45 days, they entered a mature period, and growth slowed down. The contents of chlorophyll, carotenoids, and β-carotene increased during growth. D1 has the highest accumulation of β-carotene, and GGPS enzyme activity has a positive linear relationship with the β-carotene synthesis content. Phylogenetic analysis showed that the GGPS proteins of the 15 species were highly homologous, and the GGPS protein was not part of the membrane.

2020 ◽  
Author(s):  
Fan Yang ◽  
Liang Liu ◽  
Shan Qiang ◽  
Ching Yuan Hu ◽  
Ying Li ◽  
...  

Abstract Background: β-carotene is a precursor of vitamin A and has great commercial value as an additive in foods and feeds. Many pathways not directly related to the β-carotene synthesis affect β-carotene production since the interactions among metabolic fluxes of cells confer a complex regulatory network. Engineered Y. lipolytica strain has excellent potential for β-carotene production as oleaginous yeast. Optimizing indirectly metabolic pathways in Y. lipolytica may offer a new strategy for making the β-carotene production achieve a commercially viable yield.Results: In this study, we found that the proper promotion of the multivesicular body (MVB) sorting pathway elevated the production of β-carotene by 1.58 fold when overexpressing one copy of the Did2 gene in Y. lipolytica. Through the measurement of ATP, NADPH, the mRNA, and protein level of key genes in the β-carotene synthesis pathway, the reason for β-carotene elevated was deuced that the protein level of the key enzymes (tHMG and CarA) was increased. When overexpressing two copies of the Did2 gene, the transcription level of the key genes was all elevated. However, the protein level of key enzymes in the β-carotene synthesis pathway was reduced compared with the overexpressing one copy of the Did2 gene, which resulted in reduced β-carotene content.Conclusion: This study suggests that the MVB sorting pathway is not responsible for sorting protein but has a crucial regulating effect on protein abundance in cells. Engineering the MVB sorting pathway could potentially increase the production of other high-value products. Moreover, manipulation of indirectly related metabolic pathways also is a critical strategy in synthetic biology research.


Genetics ◽  
2001 ◽  
Vol 158 (2) ◽  
pp. 635-641
Author(s):  
Bina J Mehta ◽  
Enrique Cerdá-Olmedo

Abstract Sexual interaction between strains of opposite sex in many fungi of the order Mucorales modifies hyphal morphology and increases the carotene content. The progeny of crosses of Phycomyces blakesleeanus usually include a small proportion of anomalous segregants that show these signs of sexual stimulation without a partner. We have analyzed the genetic constitution of such segregants from crosses that involved a carF mutation for overaccumulation of β-carotene and other markers. The new strains were diploids or partial diploids heterozygous for the sex markers. Diploidy was unknown in this fungus and in the Zygomycetes. Random chromosome losses during the vegetative growth of the diploid led to heterokaryosis in the coenocytic mycelia and eventually to sectors of various tints and mating behavior. The changes in the nuclear composition of the mycelia could be followed by selecting for individual nuclei. The results impose a reinterpretation of the sexual cycle of Phycomyces. Some of the intersexual strains that carried the carF mutation contained 25 mg β-carotene per gram of dry mass and were sufficiently stable for practical use in carotene production.


2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Yerong Zhu ◽  
Xiaoxue Li ◽  
Xuan Gao ◽  
Jiqi Sun ◽  
Xiaoyuan Ji ◽  
...  

Abstract Background Duckweed is considered a promising feedstock for bioethanol production due to its high biomass and starch production. The starch content can be promoted by plant growth regulators after the vegetative reproduction being inhibited. Maleic hydrazide (MH) has been reported to inhibit plant growth, meantime to increase biomass and starch content in some plants. However, the molecular explanation on the mechanism of MH action is still unclear. Results To know the effect and action mode of MH on the growth and starch accumulation in Spirodela polyrrhiza 7498, the plants were treated with different concentrations of MH. Our results showed a substantial inhibition of the growth in both fronds and roots, and increase in starch contents of plants after MH treatment. And with 75 µg/mL MH treatment and on the 8th day of the experiment, starch content was the highest, about 40 mg/g fresh weight, which is about 20-fold higher than the control. The I2-KI staining and TEM results confirmed that 75 µg/mL MH-treated fronds possessed more starch and big starch granules than that of the control. No significant difference for both in the photosynthetic pigment content and the chlorophyll fluorescence parameters of PII was found. Differentially expressed transcripts were analyzed in S. polyrrhiza 7498 after 75 µg/mL MH treatment. The results showed that the expression of some genes related to auxin response reaction was down-regulated; while, expression of some genes involved in carbon fixation, C4 pathway of photosynthesis, starch biosynthesis and ABA signal transduction pathway was up-regulated. Conclusion The results provide novel insights into the underlying mechanisms of growth inhibition and starch accumulation by MH treatment, and provide a selective way for the improvement of starch production in duckweed.


1946 ◽  
Vol 36 (2) ◽  
pp. 95-99 ◽  
Author(s):  
B. C. Ray Sarkar ◽  
K. C. Sen

1. With the object of determining the vitamin A value of carotene in different green fodders, an investigation has been undertaken to study (i) the relation between the chemically determined carotene and its biological activity as compared with that of standard carotene, (ii) the purity of apparent carotene from different sources, (iii) absorption of carotene in rats, and (iv) the relative efficiency of the standard carotene and preformed vitamin A.2. Biological tests have shown that the chemical method of assay is a fair index of the true carotene content in green fodders, and carotene in the form of an extract is quite as effective in the system as that present in the plant tissues. β-Carotene appears to be predominant in these materials.


LWT ◽  
2013 ◽  
Vol 53 (1) ◽  
pp. 378-381 ◽  
Author(s):  
Constance Reif ◽  
Eva Arrigoni ◽  
Florence Berger ◽  
Daniel Baumgartner ◽  
Laura Nyström

Plants ◽  
2020 ◽  
Vol 9 (4) ◽  
pp. 541 ◽  
Author(s):  
Beloved Mensah Dzomeku ◽  
Julian P. Wald ◽  
Jens Norbert Wünsche ◽  
Donatus Nohr ◽  
Hans K. Biesalski

Diet diversification and the exploitation of traditional, micronutrient-rich germplasm of staple crops are generally regarded as sustainable and low-cost approaches to increase the micronutrient intake of resource-poor people. Sun’s UV index was collected daily throughout the year. The study assessed the seasonality of provitamin A carotenoids in three plantain cultivars in response to climatic condition. Fruits were harvested at three maturities and freeze-dried before analysis. The results showed that there were high levels of the sun’s UV-B radiations throughout the year with the highest occurring from November to May when the area experienced clear skies with minimal cloud cover. These high levels of the sun’s UV-B index occurred between 9.00 h GMT and 17.00 h GMT. The study also showed that α-carotene content increased with maturity in “Apantu” during the rainy seasons ranging from 95 to 172 μg/100 g of dry pulp. Similar trends were observed during the dry season with a range of 28 to 489 μg/100 g. The α-carotene contents were very high in the periods of high sun’s UV-B radiations compared to the periods of low sun’s UV-B radiations. The α-carotene levels in the giant French plantains showed similar trends. Intermediate French “Oniaba” and False Horn “Apantu” plantain cultivar showed the highest content of β-carotene during the dry season. The high provitamin A carotenoid levels in the cultivars coincided with the high levels of the sun’s UV index.


2020 ◽  
Vol 4 ◽  
Author(s):  
Senthil Natesan ◽  
Thangjam Surchandra Singh ◽  
Thirusenduraselvi Duraisamy ◽  
Neelima Chandrasekharan ◽  
Sarankumar Chandran ◽  
...  

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