SUSCEPTIBILITY AND PROTECTIVE MECHANISMS OF MOTILE AND NON MOTILE CELLS OF HAEMATOCOCCUS PLUVIALIS (CHLOROPHYCEAE) TO PHOTOOXIDATIVE STRESS1

2012 ◽  
Vol 48 (3) ◽  
pp. 693-705 ◽  
Author(s):  
Danxiang Han ◽  
Junfeng Wang ◽  
Milton Sommerfeld ◽  
Qiang Hu
Keyword(s):  
Haematococcus Pluvialis ◽  
Protective Mechanisms ◽  
Motile Cells

scholarly journals NaCl Promotes the Efficient Formation of Haematococcus pluvialis Nonmotile Cells under Phosphorus Deficiency

Marine Drugs ◽  
2021 ◽  
Vol 19 (6) ◽  
pp. 337
Author(s):  
Feng Li ◽  
Ning Zhang ◽  
Yulei Zhang ◽  
Qingsheng Lian ◽  
Caiying Qin ◽  
...  
Keyword(s):  
Haematococcus Pluvialis ◽  
Phosphorus Deficiency ◽  
Cell Formation ◽  
Animal Nutrition ◽  
Cell Factory ◽  
Cell Type ◽  
Negative Effects ◽  
Related Factors ◽  
Motile Cells ◽  
Application Prospects

Natural astaxanthin helps reduce the negative effects caused by oxidative stress and other related factors, thereby minimizing oxidative damage. Therefore, it has considerable potential and broad application prospects in human health and animal nutrition. Haematococcus pluvialis is considered to be the most promising cell factory for the production of natural astaxanthin. Previous studies have confirmed that nonmotile cells of H. pluvialis are more tolerant to high intensity of light than motile cells. Cultivating nonmotile cells as the dominant cell type in the red stage can significantly increase the overall astaxanthin productivity. However, we know very little about how to induce nonmotile cell formation. In this work, we first investigated the effect of phosphorus deficiency on the formation of nonmotile cells of H. pluvialis, and then investigated the effect of NaCl on the formation of nonmotile cells under the conditions of phosphorus deficiency. The results showed that, after three days of treatment with 0.1% NaCl under phosphorus deficiency, more than 80% of motile cells had been transformed into nonmotile cells. The work provides the most efficient method for the cultivation of H. pluvialis nonmotile cells so far, and it significantly improves the production of H. pluvialis astaxanthin.

scholarly journals Comparative transcriptome analysis of astaxanthin accumulation difference between non-motile cells and akinetes of Haematococcus pluvialis

2020 ◽  
Author(s):  
Lei Fang ◽  
Jingkui Zhang ◽  
Zhongnan Fei ◽  
Minxi Wan
Keyword(s):  
Transcriptome Analysis ◽  
Haematococcus Pluvialis ◽  
Synthesis Mechanism ◽  
Motile Cells ◽  
Genes Expression ◽  
Malonyl Coa ◽  
Astaxanthin Production ◽  
Culture Process ◽  
Photosynthesis Genes ◽  
Accumulation Ability

Abstract Background: Nature astaxanthin is mainly derived from Haematococcus pluvialis. H. pluvialis has four kinds of cell morphology. Based on sequential heterotrophy-dilution-photoinduction (SHDP) technology, photoinduction using non-motile cells as seeds could result in a higher astaxanthin production than that of using brown akinetes as photoinduction seeds. To have a comprehensive understanding of this phenomenon, transcriptome analysis was conducted in this study.Results: Though most of photosynthesis genes expression were down-regulated during the SHDP culture process. Comparing with the group using brown akinetes as photoinduction seeds, the genes expression involved in astaxanthin biosynthesis, lipid biosynthesis and photosynthesis were up-regulated in the non-motile cells group. Especially, chyb gene improving the conversion of β-carotene into astaxanthin was up-regulated by 2.6-fold. The acaca gene enhancing the carboxylation of acetyl-CoA to malonyl-CoA was up-regulated by 1.4-fold.Conclusions: Astaxanthin synthesis mechanism of non-motile cells with higher astaxanthin accumulation ability than brown akinetes was attributed to the up-regulation of astaxanthin metabolism, lipid metabolism and photosynthesis-related genes expression. The results are expected to guide the optimization of astaxanthin production in H. pluvialis by improving lipid content or photosynthesis.

scholarly journals Accumulation of Astaxanthin Was Improved by the Nonmotile Cells of Haematococcus pluvialis

2019 ◽  
Vol 2019 ◽  
pp. 1-7 ◽  
Author(s):  
Feng Li ◽  
Minggang Cai ◽  
Mingwei Lin ◽  
Xianghu Huang ◽  
Jun Wang ◽  
...  
Keyword(s):  
Mortality Rate ◽  
Cell Cultures ◽  
Haematococcus Pluvialis ◽  
Morphological Changes ◽  
Continuous Light ◽  
Motile Cell ◽  
Cell Diameter ◽  
Batch Mode ◽  
Vegetative Cells ◽  
Motile Cells

The current commercial production of natural astaxanthin is mainly carried out using Haematococcus pluvialis vegetative cells in the “two-stage” batch mode. The motile vegetative cells are more sensitive to stress than nonmotile vegetative cells, thereby affecting the overall astaxanthin productivity in H. pluvialis cultures. In this study, we compared the differences between motile cells and nonmotile cells in astaxanthin productivity, morphological changes, the mortality rate, and the diameter of the formed cysts. The experimental design was achieved by two different types H. pluvialis cell under continuous light of 80 μmol photons m−2 s−1 for a 9-day induction period. The highest astaxanthin concentration of 48.42 ± 3.13 mg L−1 was obtained in the nonmotile cell cultures with the highest the productivity of 5.04 ± 0.15 mg L−1 day−1, which was significantly higher than that in the motile cell cultures. The microscopic examination of cell morphological showed a large number of photooxidative damaged cells occurring in the motile cell cultures, resulting in higher cell mortality rate (22.2 ± 3.97%) than nonmotile cell cultures (9.6 ± 0.63%). In addition, the analysis results of cell diameter statistics indicated that nonmotile cells were more conducive to the formation of large astaxanthin-rich cysts than motile cells. In conclusion, the works presented here suggest that the accumulation of astaxanthin was significantly improved by nonmotile cells of H. pluvialis, which provided a possibility of optimizing the existing H. pluvialis cultivation strategy for the industrial production.

scholarly journals Differences between Motile and Nonmotile Cells of Haematococcus pluvialis in the Production of Astaxanthin at Different Light Intensities

Marine Drugs ◽  
2019 ◽  
Vol 17 (1) ◽  
pp. 39 ◽  
Author(s):  
Feng Li ◽  
Minggang Cai ◽  
Mingwei Lin ◽  
Xianghu Huang ◽  
Jun Wang ◽  
...  
Keyword(s):  
Light Intensity ◽  
Induction Period ◽  
Cell Cultures ◽  
Haematococcus Pluvialis ◽  
Light Intensities ◽  
Motile Cells ◽  
Cell Mortality ◽  
Astaxanthin Production ◽  
Major Cell Type ◽  
The Stability

Haematococcus pluvialis, as the best natural resource of astaxanthin, is widely used in nutraceuticals, aquaculture, and cosmetic industries. The purpose of this work was to compare the differences in astaxanthin accumulation between motile and nonmotile cells of H. pluvialis and to determine the relationship between the two cells and astaxanthin production. The experiment design was achieved by two different types of H. pluvialis cell and three different light intensities for an eight day induction period. The astaxanthin concentrations in nonmotile cell cultures were significantly increased compared to motile cell cultures. The increase of astaxanthin was closely associated with the enlargement of cell size, and the nonmotile cells were more conducive to the formation of large astaxanthin-rich cysts than motile cells. The cyst enlargement and astaxanthin accumulation of H. pluvialis were both affected by light intensity, and a general trend was that the higher the light intensity, the larger the cysts formed, and the larger the quantity of astaxanthin accumulated. In addition, the relatively low cell mortality rate in the nonmotile cell cultures indicated that the nonmotile cells have a stronger tolerance to photooxidative stress. We suggest that applying nonmotile cells as the major cell type of H. pluvialis to the induction period may help to enhance the content of astaxanthin and the stability of astaxanthin production.

Modulated polarization microscopy displays the dynamics of cytoskeletal structures in living, motile cells

1995 ◽  
Vol 53 ◽  
pp. 902-903
Author(s):  
J. R. Kuhn ◽  
M. Poenie
Keyword(s):  
Mitotic Spindle ◽  
Actin Filaments ◽  
Cell Shape ◽  
Dynamic Structure ◽  
Living Cells ◽  
Cytoskeletal Proteins ◽  
Polarization Microscopy ◽  
Video Enhancement ◽  
Ultrastructural Studies ◽  
Motile Cells

Cell shape and movement are controlled by elements of the cytoskeleton including actin filaments an microtubules. Unfortunately, it is difficult to visualize the cytoskeleton in living cells and hence follow it dynamics. Immunofluorescence and ultrastructural studies of fixed cells while providing clear images of the cytoskeleton, give only a static picture of this dynamic structure. Microinjection of fluorescently Is beled cytoskeletal proteins has proved useful as a way to follow some cytoskeletal events, but long terry studies are generally limited by the bleaching of fluorophores and presence of unassembled monomers.Polarization microscopy has the potential for visualizing the cytoskeleton. Although at present, it ha mainly been used for visualizing the mitotic spindle. Polarization microscopy is attractive in that it pro vides a way to selectively image structures such as cytoskeletal filaments that are birefringent. By combing ing standard polarization microscopy with video enhancement techniques it has been possible to image single filaments. In this case, however, filament intensity depends on the orientation of the polarizer and analyzer with respect to the specimen.

A New Concept of the Pathogenesis of Retinopathy of Prematurity

2020 ◽  
pp. 5-12
Author(s):  
E.I. Sidorenko ◽  
Keyword(s):  
Growth Factors ◽  
Retinopathy Of Prematurity ◽  
Vascular Endothelium ◽  
Retinal Vessels ◽  
Protective Mechanisms ◽  
Preclinical Stage ◽  
Circulatory Hypoxia ◽  
Preclinical Phase ◽  
Vasculogenesis And Angiogenesis ◽  
Vascular Autoregulation

The lecture provides a detailed description of the development of retinal vessels, vasculogenesis and angiogenesis. The cascade of protective mechanisms of the organism of the system of combating hyperoxia, the system of combating circulatory hypoxia and the key growth factors of the vascular endothelium during angiogenesis are shown. The pathogenesis of retinopathy of prematurity is described and the first phase of ROP development is analyzed in detail, the reasons for the delay in the maturation of vascular autoregulation are explained. The author proposed to distinguish the first preclinical phase in the ROP classification. In contrast to the modern concentration of attention of ophthalmologists on the active and cicatricial stages, the author proposes to pay special attention to the study of the preclinical stage of ROP, where its pathogenesis is formed.

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